Stereological Methods I
... For sampling purposes, vertical sections from each of two blocks per sample were picked up onto 100 mesh hexagonal grids bearing a pyroxylin-carbon film. Each strip of cells within a section was sampled in a systematic random manner (Weibel, 1979) to ensure that unlabelled and labelled cell profiles were detected with equal probability. Micrographs were taken along each strip of cells at regular intervals of 16 µm, using the stage controls to move sections by increments determined from the microscope's x,y coordinate system. ...
... Counts of gold particles per unit length or area were performed on enlarged negatives, using a transparent square lattice overlay with a side (d) equal to 0.92 µm or 1.8 µm to count the intersections with profiles of the plasma membrane. The number of gold particles (N)/µm were then calculated from: N = ∑Gi/(π/4 ·d·∑Ii) where ∑Gi is the summation of the number of gold particles, ∑Ii is that of intersection counts and π/4 is a correction factor for section thickness (see Weibel, 1979;Griffiths, 1993). For counts/µm 2 the section thickness was determined by the fold procedure (Small, 1968). ...
Desmosomes are unique intercellular junctions in that they invariably contain two types of transmembrane cadherin molecule, desmocollins and desmogleins. In addition they possess a distinct cytoplasmic plaque structure containing a few major proteins including desmoplakins and the armadillo family member plakoglobin. Desmosomal cadherins are putative cell-cell adhesion molecules and we have tested their adhesive capacity using a transfection approach in mouse L cells. We find that L cells expressing either one or both of the desmosomal cadherins desmocollin 2a or desmoglein 1 display weak cell-cell adhesion activity that is Ca2+-dependent. Both homophilic and heterophilic adhesion could be detected. However, co-expression of plakoglobin with both desmosomal cadherins, but not with desmoglein 1 alone, resulted in a dramatic potentiation of cell-cell aggregation and the accumulation of detergent-insoluble desmosomal proteins at points of cell-cell contact. The effect of plakoglobin seems to be due directly to its interaction with the desmosomal cadherins rather than to its signalling function. The data suggest that the desmosome may obligatorily contain two cadherins and is consistent with a model in which desmocollins and desmogleins may form side by side heterodimers in contrast to the classical cadherins that are homodimeric. Plakoglobin may function by potentiating dimer formation, accretion of dimers to cell-cell contact sites or desmosomal cadherin stability.
... We made unbiased measurements of mitochondrial volume density and cristae surface density across the oxidative core, using stereological methods that have been previously described (Weibel, 1979;Egginton, 1990;Scott et al. 2009a). Mitochondria were classified as subsarcolemmal if they were located between the cell membrane and the outer edges of peripheral myofibrils, and intermyofibrillar if they were instead surrounded by myofibrils on all sides. ...
... We first re-analysed light microscopy images of the oxidative core that were collected as part of a previous study (using the same treatment groups) that reported data for the entire gastrocnemius (Lui et al. 2015) -where full methodologies are describedwhich allowed us to determine the fibre-type composition within the oxidative core for each population in each treatment group. Numerical densities of oxidative and fast glycolytic fibres were determined from stains of succinate dehydrogenase activity (which identifies oxidative fibres), and numerical densities of slow oxidative fibres were determined by staining for slow myosin immunoreactivity, each using stereological methods that have been well described (Weibel, 1979;Egginton, 1990). The numerical density of fast oxidative fibres was calculated as the difference between the densities of oxidative fibres and slow oxidative fibres. ...
Key points
Mitochondrial function changes over time at high altitudes, but the potential benefits of these changes for hypoxia resistance remains unclear.
We used high‐altitude‐adapted populations of deer mice, which exhibit enhanced aerobic performance in hypoxia, to examine whether changes in mitochondrial physiology or intracellular distribution in the muscle contribute to hypoxia resistance.
Permeabilized muscle fibres from the gastrocnemius muscle had higher respiratory capacities in high‐altitude mice than in low‐altitude mice.
Highlanders also had higher mitochondrial volume densities, due entirely to an enriched abundance of subsarcolemmal mitochondria, such that more mitochondria were situated near the cell membrane and adjacent to capillaries.
There were several effects of hypoxia acclimation on mitochondrial function, some of which were population specific, but they differed from the evolved changes in high‐altitude natives, which probably provide a better indication of adaptive traits that improve performance and hypoxia resistance at high altitudes.
Abstract
High‐altitude natives that have evolved to live in hypoxic environments provide a compelling system to understand how animals can overcome impairments in oxygen availability. We examined whether these include changes in mitochondrial physiology or intracellular distribution that contribute to hypoxia resistance in high‐altitude deer mice ( Peromyscus maniculatus ). Mice from populations native to high and low altitudes were born and raised in captivity, and as adults were acclimated to normoxia or hypobaric hypoxia (equivalent to 4300 m elevation). We found that highlanders had higher respiratory capacities in the gastrocnemius (but not soleus) muscle than lowlanders (assessed using permeabilized fibres with single or multiple inputs to the electron transport system), due in large part to higher mitochondrial volume densities in the gastrocnemius. The latter was attributed to an increased abundance of subsarcolemmal (but not intermyofibrillar) mitochondria, such that more mitochondria were situated near the cell membrane and adjacent to capillaries. Hypoxia acclimation had no significant effect on these population differences, but it did increase mitochondrial cristae surface densities of mitochondria in both populations. Hypoxia acclimation also altered the physiology of isolated mitochondria by affecting respiratory capacities and cytochrome c oxidase activities in population‐specific manners. Chronic hypoxia decreased the release of reactive oxygen species by isolated mitochondria in both populations. There were subtle differences in O 2 kinetics between populations, with highlanders exhibiting increased mitochondrial O 2 affinity or catalytic efficiency in some conditions. Our results suggest that evolved changes in mitochondrial physiology in high‐altitude natives are distinct from the effects of hypoxia acclimation, and probably provide a better indication of adaptive traits that improve performance and hypoxia resistance at high altitudes.
... Ultrathin sections, stained with uranyl acetate and lead citrate, were examined with a Tecnai 12 Spirit G2 BioTwin transmission electron microscope (FEI, USA). For quantitative studies, 30 electronograms at a magnification of 8000x were taken from each explant using a modified systematic random sampling (Weibel 1979). A point count analysis (Weibel 1979) was employed, as characterized in detail in our previous work (Lewczuk and Przybylska-Gornowicz 1997), to estimate the relative volume (expressed as the percent of cytoplasm of pinealocyte perikaryon) and the numerical density of mitochondria (expressed as the number of mitochondria per 60 μm 2 ). ...
... For quantitative studies, 30 electronograms at a magnification of 8000x were taken from each explant using a modified systematic random sampling (Weibel 1979). A point count analysis (Weibel 1979) was employed, as characterized in detail in our previous work (Lewczuk and Przybylska-Gornowicz 1997), to estimate the relative volume (expressed as the percent of cytoplasm of pinealocyte perikaryon) and the numerical density of mitochondria (expressed as the number of mitochondria per 60 μm 2 ). The percentages of mitochondria occurring in the form of small isolated particles or complexes (networks and extended filaments) were also determined. ...
Norepinephrine released from sympathetic innervation plays the main role in the regulation of melatonin secretion in mammalian pinealocytes. The present study was conducted for the following reasons: 1) to establish whether the pinealocyte chondriome is controlled by norepinephrine, 2) to determine the effect of adrenergic stimulation on mitochondria, and 3) to characterize adrenoceptors involved in the regulation of the chondriome.
The static organ culture of the pineal gland was used. The explants were incubated for 5 consecutive days in control medium and between 20:00 and 08:00 in medium with the presence of 10 μM norepinephrine – adrenergic agonist; isoproterenol – beta-adrenoceptor agonist; cirazoline, methoxamine, M-6364 – alfa
The incubation of explants in the presence of norepinephrine or isoproterenol caused a decrease in the relative volume and the numerical density of mitochondria and induced an increase in the percentage of free mitochondria in pinealocytes. Significant changes in these parameters were not observed after treatment with methoxamine, cirazoline, M-6463 and PMA.
The results obtained show that the chondriome of pig pinealocytes is controlled by norepinephrine acting via beta-adrenoceptors. Adrenergic stimulation, repeated for five consecutive days of organ culture, causes a decrease in the number of mitochondria and a shift in the distribution of mitochondria from the form of networks and filaments into the form of single particles. This indicates the intensive remodeling of the mitochondria network, which is closely linked to the metabolic status of the cell.
... Stereology is a morphometric tool that combines strict sampling rules and simple mathematics which allow unbiased and efficient estimation of three dimensional quantities from two dimensional histological sections (Weibel et al., 1966; Weibel, 1979; Dunnill, 1982 and Mayhew, 1983). The use of stereological methods in studies of placental structure and interpretation of placental functional morphology from the whole organ to the molecular level has been described by Baur (1973), Quantitativemorphometric data have been obtained for various organs including the placenta (Laga et al., 1973 and Laga et al., 1974). ...
... A high degree of accuracy can be attained by adjusting the sample size. This is achieved by a procedure of systematic random sampling (Weibel, 1979). This method of sampling was adopted in this study because it is more precise and efficient in the estimation of morphometric parameters (Mayhew, 1983). ...
This book provides quantitative morphometric data on the normally delivered placenta of Sudanese women, using standard stereological methods. The volume densities of the components of the placenta and the surface area of the fetal-maternal interface (trophoblast) form the basis of comparing these parameters with those prevailing under pregnancy complications such as preeclampsia and diabetes. The parameters are also essential for comparisons with placentas from other ethnic groups.
... Planimetric mitochondrial measurements of PCT cells were performed on pictures containing whole cells (see Figs S1 and S2) and using ImageJ software. From the same pictures, we obtained the mitochondrial stereological parameters Volume density (Vv) and Numerical density (Nv) using the semi-automatic application 'WimStereology' (Wimasis SL, C ordoba, Spain), based on a simple square lattice test system (Weibel, 1979). The relative number of autophagosomes and autophagic-related figures per cell surface area was also scored for each dietary group. ...
... Numerical density was calculated using the formula where " Na " represents the number of mitochondria per μm 2 of cell and " k " and " β " the mitochondrial size distribution and shape coefficient, respectively. These coefficients were calculated using the results of planimetric measurements (Weibel, 1979). Planimetric measurements on mitochondria were performed using the same automatic software. ...
Calorie restriction (CR) has been repeatedly shown to prevent cancer, diabetes, hypertension, and other age-related diseases in a wide range of animals, including non-human primates and humans. In rodents, CR also increases lifespan and is a powerful tool for studying the aging process. Recently, it has been reported in mice that dietary fat plays an important role in determining lifespan extension with 40% CR. In these conditions, animals fed lard as dietary fat showed an increased longevity compared with mice fed soybean or fish oils. In this paper, we study the effect of these dietary fats on structural and physiological parameters of kidney from mice maintained on 40% CR for 6 and 18 months. Analyses were performed using quantitative electron microcopy techniques and protein expression in Western blots. CR mitigated most of the analyzed age-related parameters in kidney, such as glomerular basement membrane thickness, mitochondrial mass in convoluted proximal tubules and autophagic markers in renal homogenates. The lard group showed improved preservation of several renal structures with aging when compared to the other CR diet groups. These results indicate that dietary fat modulates renal structure and function in CR mice and plays an essential role in the determination of health span in rodents.
... The VvBAS of mussels was determined microscopically with a Weibel graticule eye piece (M-168; Weibel, 1979). Counts were made in 10 fields of view for each mussel (400× magnification). ...
An integrated biological effects study using field transplanted mussels was applied to determine the potential biological effects of an effluent discharge from an aluminium smelter into a Norwegian fjord. Chemical body burden and biological effects were measured in mussels positioned downstream (1, 2, 5, 10 and 20 km) from the aluminium smelters discharge for a period of 6 weeks. A suite of biomarkers, from whole organism to subcellular responses were measured. Chemical concentrations in mussel tissues were low; however, a change in the PAC (polyaromatic compound) profile from high to low pyrogenic influence provided evidence of exposure to the smelter's effluent. Overall, the biological responses observed where greater in the mussels positioned closest to the smelter (1-5 km). Lowest chemical accumulation and biomarker responses were observed in mussels positioned 10 km from the smelter and were considered as the reference field population. Mussels located furthest from the smelter (20 km) exhibited significant biomarker responses and suggested a different contaminant source within the fjord. The integrated biological response index (IBR) was applied and reflected the expected level of exposure to the smelters discharge, with highest IBR calculated in mussels positioned closest to the discharge (1-5 km). Principal component analysis (PCA) also differentiated among mussel groups, with the most impacted located closest to the smelter. Not one chemical factor could explain the biological responses observed in mussels, but the presence of PAH16, PAH41 and metals Mn, Ni and Cr were the main contributors measured to the higher stress seen in the mussels from the 1 and 5 km groups.
... Grid sizes of 60 and 270 nm were used to estimate mitochondria volume and cristae surface area, respectively. The general principle of estimating S v and V V by stereological methods can be found elsewhere (Weibel, 1980). The images were analysed by two blinded investigators, who contributed equally to all the different groups of subjects. ...
Key points:
In human skeletal muscles, the current view is that the capacity for mitochondrial energy production, and thus endurance capacity, is set by the mitochondria volume. However, increasing the mitochondrial inner membrane surface comprises an alternative mechanism for increasing the energy production capacity. In the present study, we show that mitochondrial inner membranes in leg muscles of endurance-trained athletes have an increased ratio of surface per mitochondrial volume. We show a positive correlation between this ratio and whole body oxygen uptake and muscle fibre mitochondrial content. The results obtained in the present study help us to understand modulation of mitochondrial function, as well as how mitochondria can increase their oxidative capacity with increased demand.
Abstract:
Mitochondrial energy production involves the movement of protons down a large electrochemical gradient via ATP synthase located on the folded inner membrane, known as cristae. In mammalian skeletal muscle, the density of cristae in mitochondria is assumed to be constant. However, recent experimental studies have shown that respiration per mitochondria varies. Modelling studies have hypothesized that this variation in respiration per mitochondria depends on plasticity in cristae density, although current evidence for such a mechanism is lacking. In the present study, we confirm this hypothesis by showing that, in human skeletal muscle, and in contrast to the current view, the mitochondrial cristae density is not constant but, instead, exhibits plasticity with long-term endurance training. Furthermore, we show that frequently recruited mitochondria-enriched fibres have significantly increased cristae density and that, at the whole-body level, muscle mitochondrial cristae density is a better predictor of maximal oxygen uptake rate than muscle mitochondrial volume. Our findings establish an elevating mitochondrial cristae density as a regulatory mechanism for increasing metabolic power in human skeletal muscle. We propose that this mechanism allows evasion of the trade-off between cell occupancy by mitochondria and other cellular constituents, as well as improved metabolic capacity and fuel catabolism during prolonged elevated energy requirements.
... glycogen area fraction, t is the section thickness (60 nm), B A is the glycogen boundary length 263 density, N A is the number of particles per area, and H is the average glycogen particle diameter 264(Weibel 1980). Glycogen particles were assumed to be spherical (Melendez-Hevia et al. 1993). ...
Key points:
Glycogen is stored in local spatially distinct compartments within skeletal muscle fibres and is the main energy source during supramaximal exercise. Using quantitative electron microscopy, we show that supramaximal exercise induces a differential depletion of glycogen from these compartments and also demonstrate how this varies with fibre types. Repeated exercise alters this compartmentalized glycogen depletion. The results obtained in the present study help us understand the muscle metabolic dynamics of whole body repeated supramaximal exercise, and suggest that the muscle has a compartmentalized local adaptation to repeated exercise, which affects glycogen depletion.
Abstract:
Skeletal muscle glycogen is heterogeneously distributed in three separated compartments (intramyofibrillar, intermyofibrillar and subsarcolemmal). Although only constituting 3-13% of the total glycogen volume, the availability of intramyofibrillar glycogen is of particular importance to muscle function. The present study aimed to investigate the depletion of these three subcellular glycogen compartments during repeated supramaximal exercise in elite athletes. Ten elite cross-country skiers (aged 25 ± 4 years, V̇O2 max : 65 ± 4 ml kg-1 min-1 ; mean ± SD) performed four ∼4 min supramaximal sprint time trials (STT 1-4) with 45 min of recovery. The subcellular glycogen volumes in musculus triceps brachii were quantified from electron microscopy images before and after both STT 1 and 4. During STT 1, the depletion of intramyofibrillar glycogen was higher in type 1 fibres [-52%; (-89:-15%)] than type 2 fibres [-15% (-52:22%)] (P = 0.02), whereas the depletion of intermyofibrillar glycogen [main effect: -19% (-33:0%), P = 0.006] and subsarcolemmal glycogen [main effect: -35% (-66:0%), P = 0.03] was similar between fibre types. By contrast, only intermyofibrillar glycogen volume was significantly reduced during STT 4, in both fibre types [main effect: -31% (-50:-11%), P = 0.002]. Furthermore, for each of the subcellular compartments, the depletion of glycogen during STT 1 was associated with the volumes of glycogen before STT 1. In conclusion, the depletion of spatially distinct glycogen compartments differs during supramaximal exercise. Furthermore, the depletion changes with repeated exercise and is fibre type-dependent.
... Moreover, together with George Palade, he described a new organelle in pulmonary arterial endothelial cells which was later termed " Weibel-Palade body " (Weibel and Palade 1964). A most significant contribution to microscopy by Ewald Weibel was to the development of stereological methods (Weibel and Gomez 1962; Weibel 1963 Weibel , 1979a Weibel , 1980 Weibel , 2013 ). Derived from the sound mathematical principles of stochastic geometry, stereology provides methods for quantitative assessment of objects in microscopy. ...
In the nineteenth century, there was a dispute about the existence of a lung alveolar epithelium which remained unsolved until the invention of electron microscopy (EM) and its application to the lung. From the early 1960s, Ewald Weibel became the master of lung EM. He showed that the alveolar epithelium is covered with a lining layer containing surfactant. Weibel also explained the phenomenon of “non-nucleated plates” observed already in 1881 by Albert Kölliker. Weibel’s most significant contribution was to the development of stereological methods. Therefore, quantitative characterization of lung structure revealing structure–function relationships became possible. Today, the spectrum of EM methods to study the fine structure of the lung has been extended significantly. Cryo-preparation techniques are available which are necessary for immunogold labeling of molecules. Energy-filtering techniques can be used for the detection of elements. There have also been major improvements in stereology, thus providing a very versatile toolbox for quantitative lung phenotype analyses. A new dimension was added by 3D EM techniques. Depending on the desired sample size and resolution, the spectrum ranges from array tomography via serial block face scanning EM and focused ion beam scanning EM to electron tomography. These 3D datasets provide new insights into lung ultrastructure. Biomedical EM is an ever-developing field. Its high resolution remains unparalleled. Moreover, EM has the unique advantage of providing an “open view” into cells and tissues within their full architectural context. Therefore, EM will remain an indispensable tool for a better understanding of the lung’s functional design.
... Mineral perimeter densities were then computed by dividing by the area fraction of each mineral , where the area fractions were calculated by dividing the pixels of each mineral by the total number of image pixels . Based on principles originating in stereology, 3D surface area densities (surface area over volume) can be computed from 2D perimeter densities (perimeter over area) using a bias correction factor (Weibel, 1979 ). Applying the bias correction factor for spheres of 4/p mineral specific surface area densities were computed in units of mm 2 /mm 3 . ...
Our limited understanding of mineral reactive surface area contributes to significant uncertainties in quantitative simulations of reactive chemical transport in subsurface processes. Continuum formulations for reactive transport typically use a number of different approximations for reactive surface area, including geometric, specific, and effective surface area. In this study, reactive surface area estimates are developed and evaluated for their ability to predict dissolution rates in a well-stirred flow-through reactor experiment using disaggregated samples from the Nagaoka pilot CO2 injection site (Japan). The disaggregated samples are reacted with CO2 acidified synthetic brine under conditions approximating the field conditions and the evolution of solute concentrations in the reactor effluent is tracked over time. The experiments, carried out in fluid-dominated conditions at a pH of 3.2 for 650 hours, resulted in substantial dissolution of the sample and release of a disproportionately large fraction of the divalent cations. Traditional reactive surface area estimation methods, including an adjusted geometric surface area and a BET-based surface area, are compared to a newly developed image-based method. Continuum reactive transport modeling is used to determine which of the reactive surface area models provides the best match with the effluent chemistry from the well-stirred reactor. The modeling incorporates laboratory derived mineral dissolution rates reported in the literature and the initial modal mineralogy of the Nagaoka sediment was determined from scanning electron microscopy (SEM) characterization. The closest match with the observed steady-state effluent concentrations was obtained using specific surface area estimates from the image-based approach supplemented by literature-derived BET measurements. To capture the evolving effluent chemistry, particularly over the first 300 hours of the experiment, it was also necessary to account for the grain size distribution in the sediment and the presence of a highly reactive volcanic glass phase that shows preferential cation leaching.
... Micro-computed tomography (μCT) is the gold standard for quantifying trabecular and cortical bone microarchitecture in small animal models (Bouxsein et al., 2010). MicroCT is able to directly measure trabecular bone architecture without having to rely on stereological models that were previously utilized for histological assessment of bone structure (Hildebrand et al., 1999;Weibel, 1980). However, there are numerous variables associated with the data acquisition, processing, and evaluation of μCT scans that can affect morphologic results obtained from bone samples. ...
Micro-computed tomography (μCT) is currently the gold standard for determining trabecular bone microstructure in small animal models. Numerous parameters associated with scanning and evaluation of μCT scans can strongly affect morphologic results obtained from bone samples. However, the effect of these parameters on specific trabecular bone outcomes is not well understood. This study investigated the effect of μCT scanning with nominal voxel sizes between 6-30 μm on trabecular bone outcomes quantified in mouse vertebral body trabecular bone. Additionally, two methods for determining a global segmentation threshold were compared: based on qualitative assessment of 2D images, or based on quantitative assessment of image histograms. It was found that nominal voxel size had a strong effect on several commonly reported trabecular bone parameters, in particular connectivity density, trabecular thickness, and bone tissue mineral density. Additionally, the two segmentation methods provided similar trabecular bone outcomes for scans with small nominal voxel sizes, but considerably different outcomes for scans with larger voxel sizes. The Qualitatively Selected segmentation method more consistently estimated trabecular bone volume fraction (BV/TV) and trabecular thickness across different voxel sizes, but that the Histogram segmentation method more consistently estimated trabecular number, trabecular separation, and structure model index. Altogether, these results suggest that high-resolution scans be used whenever possible to provide the most accurate estimation of trabecular bone microstructure, and that the limitations of accurately determining trabecular bone outcomes should be considered when selecting scan parameters and making conclusions about inter-group variance or between-group differences in studies of trabecular bone microstructure in small animals.
... The volume density (VD) is similar to the frequently used dye coverage. It is defined as the stained volume divided by the reference space and originated from the methods of stereology, which relates a three-dimensional parameter to two-dimensional measurements (Weibel, 1979). Surface density (SD) is defined as surface area of an object divided by the volume of the reference space. ...
Climate change is expected to impact the water cycle and severely affect
precipitation patterns across central Europe and in other parts of the
world, leading to more frequent and severe droughts. Usually when projecting
drought impacts on hydrological systems, it is assumed that system
properties, like soil properties, remain stable and will not be affected by
drought events. To study if this assumption is appropriate, we address the
effects of drought on the infiltration behavior of forest soils using dye
tracer experiments on six sites in three regions across Germany, which were
forced into drought conditions. The sites cover clayey-, loamy- and sandy-textured soils. In each region, we compared a deciduous and a coniferous
forest stand to address differences between the main tree species. The
results of the dye tracer experiments show clear evidence for changes in
infiltration behavior at the sites. The infiltration changed at the clayey
plots from regular and homogeneous flow to fast preferential flow. Similar
behavior was observed at the loamy plots, where large areas in the upper
layers remained dry, displaying signs of strong water repellency. This was
confirmed by water drop penetration time (WDPT) tests, which revealed, in
all except one plot, moderate to severe water repellency. Water repellency
was also accountable for the change of regular infiltration to fingered flow
in the sandy soils. The results of this study suggest that the
drought history or, more generally, the climatic conditions of a soil in the past are more important than the actual antecedent soil moisture status
regarding hydrophobicity and infiltration behavior; furthermore, drought
effects on infiltration need to be considered in hydrological models to
obtain realistic predictions concerning water quality and quantity in runoff
and groundwater recharge.
To provide concise and brief important stereological application methods and techniques for estimating biological tissues. Stereology studies the quantity of biological tissue using little practice and the low price of counting and preparing tissue slices to obtain direct and accurate results. Since their establishment, the stereological techniques underwent much improvement, thus allowing more precise analysis of target structures using various approaches. Using stereological tools, advances in stereological techniques made the target tissues or organs represented by 2D instead of 3D dimensions. Process tools estimate volume, area and length. According to the exciting tissue and aims, the stereological tools perform differently. This review summarizes various stereological tools and techniques, providing brief information about the orientation method, slicer probe method, Delesse's principle, Cavalieri principle, disector, fractionator, nucleator, virtual cycloids and saucer, which are described in detail.
Carbonates exhibits diverse flow characteristics at pore scale. Petrographic study reveals micro-level heterogeneities. Thin sections are key to assess reservoir quality although these are images and interpretations in text format. Thin section microscopic analysis is descriptive and subjective. To an extent, optical point counting is routinely used quantitatively to estimate porosity, cement, and granular features. Overall, thin section descriptions require specialist human skill and an extensive effort, as it is repetitive and time consuming. Thus, a manual process limits the overall progress of rock quality assessment. There is no recognized method to handle thin sections for direct input with conventional core data due to its image and descriptive nature of data. An automated image processing is one of the emerging concepts designed in this paper to batch process thin sections for digital reservoir descriptions and cross correlating the results with conventional core analysis data.
Thin section images are photomicrographs under plane polarized light. Initially, denoise and image enhancement techniques were implemented to preserve elemental boundaries. Computational algorithms mainly, multilevel thresholding and pixel intensity clustering algorithms were programmed to segment images for extracting elements from segmented regions. The extracted elements were compared with original image for labeling. The labeled elements are interpreted for geological elements such as matrix, pores, cement, and other granular content. The interpreted geological elements are then measured for their physical properties like area, equivalent diameter, perimeter, solidity, eccentricity, and entropy. 2D-Porosity, polymodal pore size distribution, mean pore size, cement and granular contents were then derived for each thin section image. The estimated properties were compared with conventional core after calibrating with laboratory NMR data. The whole process is automated in a batch process for a specific reservoir type and computational cost is analyzed for optimization.
2D-porosity is in excellent agreement with core porosity, thus reducing uncertainty that arises from visual estimations. Scale related issues were highlighted between 2D porosity and core porosity for some samples. Polymodal pore size distributions are in good correlation with NMR T2 distribution compared to MICP distributions. The correlation coefficient was understood to be equivalent to surface relaxivity. A digital dataset consisting of 2D porosity, eccentricity, entropy, mean pore size, cement and grain contents is automatically extracted in csv format. The digital dataset, which was previously in text format in conventional analysis, is now a rich quantitative dataset.
This paper demonstrated a unique and customized solution to extract digital reservoir descriptions for geoscience applications. This significantly reduced the subjectivity in visual descriptions. The solution presented is scalable to large number of samples with significant reduction in turnaround and effort compared to conventional techniques. Additional merit is that the result from this method has direct correlation to conventional core data for improving rock typing workflows. This paper presents a novel means to use thin section images directly in digital format in geoscience applications.
Aim:
To evaluate the effect of pancreatic ductal cells on experimental human islet transplantation.
Materials and methods:
Isolated islets were additionally purified by handpicking. Ductal cells were purified by magnetic cell sorting and then clustered into ductal pancreatospheres (DPS). Islets, DPS, and islets + DPS (100 islets + 75 DPS, or 100 islets + 200 DPS) were cultured and glucose-stimulated insulin secretion, β-cell apoptosis, and gene expression was determined. Islets and islets + DPS preparations (800 islets + 600 DPS) were transplanted to streptozotocin-treated immunodeficient mice and glycemia, graft morphometry, and gene expression were determined.
Results:
Insulin stimulation index was higher in islets than in islets co-cultured with DPS (5.59 ± 0.93 vs 4.02 ± 0.46; p<0.05). IL1B and CXCL11 expression was higher in 100 islets + 200 DPS than in islets (p<0.01), and IL-1β was detected in supernatants collected from DPS and islets + DPS preparations, but not in islets. Hyperglycemia developed in 33% and 67% of mice transplanted with islets or with islets + DPS respectively. β-cell mass was 26% lower in islets + DPS than in islets grafts (p>0.05), and the ratio β-/endocrine non-β-cell mass was lower in islets + DPS grafts (islets: 2.05 ± 0.18, islets + DPS: 1.35 ± 0.15; p<0.01). IL1B and IL1RN expression was significantly higher in islets + DPS grafts.
Conclusions:
Islet preparations enriched with ductal cells have a lower insulin stimulation index in vitro and achieved a worse metabolic outcome after transplantation. Inflammation may mediate the deleterious effects of ductal cells on islet cells.
Neurobiological models have provided consistent evidence of the involvement of cortical–subcortical circuitry in obsessive–compulsive disorder (OCD). The orbitofrontal cortex (OFC), involved in motivation and emotional responses, is an important regulatory node within this circuitry. However, OFC abnormalities at the cellular level have so far not been studied. To address this question, we have recruited a total of seven senior individuals from the Sao Paulo Autopsy Services who were diagnosed with OCD after an extensive post-mortem clinical evaluation with their next of kin. Patients with cognitive impairment were excluded. The OCD cases were age- and sex-matched with 7 control cases and a total of 14 formalin-fixed, serially cut, and gallocyanin-stained hemispheres (7 subjects with OCD and 7 controls) were analyzed stereologically. We estimated laminar neuronal density, volume of the anteromedial (AM), medial orbitofrontal (MO), and anterolateral (AL) areas of the OFC. We found statistically significant layer- and region-specific lower neuron densities in our OCD cases that added to a deficit of 25% in AM and AL and to a deficit of 21% in MO, respectively. The volumes of the OFC areas were similar between the OCD and control groups. These results provide evidence of complex layer and region-specific neuronal deficits/loss in old OCD cases which could have a considerable impact on information processing within orbitofrontal regions and with afferent and efferent targets.
Stereological principles were used to study epidermal cell redifferentiation during the post-genital tissue union in the developing flowers of Catharanthus roseus. Volume densities of ultrastructural components at three separate stages of cell differentiation were analyzed and compared. Nuclear volume density decreased and vacuolar volume density increased throughout the period studied. The only other components whose volume densities changed significantly were plastids, mitochondria, and dictyosomes. For each of these organelles, the mean relative volume was greatest at the time of fusion. By 12 hr after fusion, however, the mean relative volume of each fell to a level significantly lower than its volume in the prefusion cells.
The mechanisms by which Venus's Flytrap (Dionaea muscipula Ellis) close are not clearly understood, and several conflicting models have been proposed. We have measured the dynamics of five trap tissues from three trap regions during full closure of young, fully developed, previously unclosed traps. Closure was divided into three distinct stages: 1) Capture–occurred immediately after stimulation of the trigger hairs and involved the rapid inward flexure of the trap margin and tynes. This motion interlocked the tynes, effectively capturing the prey. This was the only rapid movement of the trap; 2) Appression–completed by 30 min poststimulation, was characterized by contact of the margins; and 3) Sealing–completed by 1 hr poststimulation, was characterized by a sealed “digestive” sac formed around the potential prey, also by tight appression and recurved bending of the trap–margins. Major tissue dynamics that facilitated changes in trap morphology (hence, closure) occurred in different regions of the trap during different periods of time. The first regions where activity occurred were the A and C regions (Fig. 1), after approximately 15 min poststimulation; tissues in the C regions were most active followed by those in the B region of the trap (30 min to 1 hr poststimulation). Thus, shape changes during each stage of closure were the result of temporally separated changes in trap tissue volume. The complete sequence of events was elicited by a single 5–sec period of trigger hair stimulation. Our study showed that changes in the curvature of the trap during closure involved the expansion of opposing tissue groups (i.e., on opposite sides of trap medullary tissues). The pressure from contact of opposing trap lobes during the Appression stage may play an important role in regulating further trap closure and morphology.
Two genomic variants of a chickpea (Cicer arietinum L.) parental line have been developed which exhibit gigas characters. The two genotypes were the result of a single-gene mutation (gigas) and induced tetraploidy of a single parental line. The two genotypes plus parental strain were investigated to determine the similarity-of-effect of polyploidy and this single-gene mutation on leaf anatomy and morphology. Leaves consisted of two rows of alternatively arranged leaflets. Both the tetraploid and parental lines had the same mean number of leaflets per leaf while the gigas plants had fewer, but mean total leaf surface area was greater in the gigas plants. Quantitative comparison of mesophyll and vascular tissue and air space volume density (Vv) showed that leaves of the tetraploid plants had the greatest mesophyll cell density (Vvm) and least air space density. Mesophyll cell density was equal in the parental and single-gene mutant while parental leaves had the greatest vascular tissue density. The greater mesophyll cell density values of the polyploid were due to larger mean mesophyll cell size, not to greater cell numbers per unit area. Leaf models based on tissue density and leaflet size showed tetraploid plants had the greatest productivity potential per unit of leaflet surface area. However, if models were based on a whole leaf, gigas plants had the greatest productivity potential since they had larger total leaf area. The effectiveness of using structural models to predict physiological potential in plant tissues will be tested in future studies.
A quantitative light and electron microscope study of developing and degenerating mycorrhizal arbuscules of Glomus fasciculatum in Zea mays was carried out in order to estimate three parameters during the colonization cycle. These were: 1) Vv(f,c), the fraction of the host cell volume occupied by a volume of fungus; 2) Vv(cy,c), the fraction of the host cell volume occupied by host cytoplasm; 3) Sv(pr,c), the surface-area-to-volume ratio of the host protoplast to the whole host cell. Uninfected cortical cells had an Sv(pr,c) of 0.13 μm²/μm³. As the fungus penetrates the cell wall, the protoplast invaginates, causing a decrease in protoplast volume and an increase in protoplast Sv. The Sv(pr,c) of a cell containing a mature arbuscule is 1.275 μm²/μm³. Because of the shrinkage of the protoplast, the Sv of the protoplast to its own volume rather than the original cell volume is 2.55 μm²/μm³, or almost a 20-fold increase. Total cell size is unaffected. When the arbuscule is mature, the fungus occupies 42% of the cell, with 24% as 1-μm-diam branches, and 18% as trunk. Arbuscular branch formation progresses at a linear rate and is the most important factor in causing the increased host Sv. The correlation coefficient for Vv(br,c) the volume fraction for arbuscular branches, vs. Sv(pr,c) is r = 0.932 (P < 0.001). Degeneration of the arbuscule is marked by a rapid decrease in branches, host Sv, and host cytoplasm. The trunk develops and degenerates at a slower rate than the branches.
Mature sunflower leaves were exposed to partial shading (35 or 14% of normal sun) or darkness (0% of normal sun) for approximately 8 hr. During this period one-half of each test leaf was shaded; the other half was used as a normal sun control. Palisade cell structure from both halves of each leaf was compared. Shading of leaves had little effect on organelle percent volume values (Vv) with exception of the starch compartment which decreased as shading increased. The surface to volume ratio (Sv) of the chloroplast thylakoids increased while the Sv of the mitochondrial membranes decreased as shading increased. Palisade cell volume did not change in shaded portions of the leaf, except in the fully shaded (dark) tissues where cell volume decreased. Changes in the actual volume of organelle compartments were strongly correlated with changes in cell volume. Thus a general osmotic response may account for some of the volume changes associated with differences in light intensity. Shading increased thylakoid surface areas 10–30% over the full sun controls. The ratio of stromal to granal thylakoid surface area remained constant in both the control and partially shaded samples. However, in darkened samples this ratio decreased as stromal membranes increased more than granal membranes. Changes observed in thylakoid surface areas associated with shading did not support thylakoid models which propose the interconversion of granal membranes to stromal membranes and vice versa.
Aim:
We examined the effects of chronic hypoxia on diaphragm function in high- and low-altitude populations of Peromyscus mice.
Methods:
Deer mice (P. maniculatus) native to high altitude and congeneric mice native to low altitude (P. leucopus) were born and raised in captivity to adulthood, and were acclimated to normoxia or hypobaric hypoxia (12 or 9 kPa, simulating hypoxia at 4300 m and 7000 m) for 6-8 weeks. We then measured indices of mitochondrial respiration capacity, force production, and fatigue resistance in the diaphragm.
Results:
Mitochondrial respiratory capacities (assessed using permeabilized fibres with single or multiple inputs to the electron transport system), citrate synthase activity (a marker of mitochondrial volume), twitch force production, and muscle fatigue resistance increased after exposure to chronic hypoxia in both populations. These changes were not well explained by variation in the fibre-type composition of the muscle. However, there were several differences in diaphragm function in high-altitude mice compared to low-altitude mice. Exposure to a deeper level of hypoxia (9 kPa vs 12 kPa) was needed to elicit increases in mitochondrial respiration rates in highlanders. Chronic hypoxia did not increase the emission of reactive oxygen species from permeabilized fibres in highlanders, in contrast to the pronounced increases that occurred in lowlanders. In general, the diaphragm of high-altitude mice had greater capillary length densities, produced less force in response to stimulation, and had shorter relaxation times. The latter was associated with higher activity of sarcoplasmic reticulum Ca2+ -ATPase (SERCA) activity in the diaphragm of high-altitude mice.
Conclusion:
Overall, our work suggests that exposure to chronic hypoxia increases the capacities for mitochondrial respiration, force production, and fatigue resistance of the diaphragm. However, many of these effects are opposed by evolved changes in diaphragm function in high-altitude natives, such that highlanders in chronic hypoxia maintain similar diaphragm function to lowlanders in sea level conditions. This article is protected by copyright. All rights reserved.
Objective:To estimate the in vivo dimensions of the fetal villous tree of the normal term placenta.
In global climate change scenarios, seawater warming acts in concert with multiple stress sources, which may enhance the susceptibility of marine biota to thermal stress. Here, the responsiveness to seasonal gradual warming was investigated in temperate mussels from a chronically stressed population in comparison with a healthy one. Stressed and healthy mussels were subjected to gradual temperature elevation for 8 days (1°C per day; fall: 16–24°C, winter: 12–20°C, summer: 20–28°C) and kept at elevated temperature for 3 weeks. Healthy mussels experienced thermal stress and entered the time-limited survival period in the fall, became acclimated in winter and exhibited sublethal damage in summer. In stressed mussels, thermal stress and subsequent health deterioration were elicited in the fall but no transition into the critical period of time-limited survival was observed. Stressed mussels did not become acclimated to 20°C in winter, when they experienced low-to-moderate thermal stress, and did not experience sublethal damage at 28°C in summer, showing instead signs of metabolic rate depression. Overall, although the thermal threshold was lowered in chronically stressed mussels, they exhibited enhanced tolerance to seasonal gradual warming, especially in summer. These results challenge current assumptions on the susceptibility of marine biota to the interactive effects of seawater warming and pollution.
The study of the structural basis of gas exchange function in the lung depends on the availability of quantitative information that concerns the structures establishing contact between the air in the alveoli and the blood in the alveolar capillaries, which can be entered into physiological equations for predicting oxygen uptake. This information is provided by morphometric studies involving stereological methods and allows estimates of the pulmonary diffusing capacity of the human lung that agree, in experimental studies, with the maximal oxygen consumption. The basis for this “machine lung” structure lies in the complex design of the cells building an extensive air-blood barrier with minimal cell mass.
Laryngeal papillomas from 20 patients (162 papillomas) were subjected to histomorphometric analysis: Based on clinical parameters, the papillomas were divided into juvenile multiple papillomas, adult multiple papillomas and adult solitary papillomas. The volume fractions of basal cells, koilocytes and nuclei as well as the mean nuclear volume were determined for each group. Significant differences between the 3 groups were not found and it is therefore concluded that they all represent the same basic lesion.
An accurate quantitative analysis of the microstructure including immiscible polymer phases (if any) and dispersion/distribution of nanoparticles in the matrix is essential to understand the relation between processing and ultimate properties of nanocomposites. Here, we have reviewed the problems associated with proper microstructural characterization of nanocomposites and their influence on precisely concluding the effect on different properties.
Die Herzhypertrophie wird seit mehr als 100 Jahren in zwei Formen, die idiopathische primäre und die sekundäre Form eingeteilt (Friedreich 1861). Im heutigen ärztlichen Sprachgebrauch hat sich der Begriff „Kardiomyopathie“ gegen den Begriff „idiopathische Herzhypertrophie“ durchgesetzt (Brigden 1957), da mit primären (idiopathischen) Kardiomyopathien meist eine Herzhypertrophie assoziiert ist (Goodwin u. Oakley 1972). Den primären Kardiomyopathien, deren Ursache nicht bekannt ist, werden die sekundären Kardiomyopathien gegenübergestellt (Kühler et al. 1973), bei denen ein Zusammenhang mit Infektionen (Myokarditis), genetisch bedingten Enzymdefekten (Thesaurismosen), physikalischen Läsionen (mechanische Schäden, energiereiche Strahlung) oder mit toxischen und nutritiven Störungen (Alkohol, Thiaminmangel) besteht.
The functional morphologist asks, “Just how structurally well suited are gills and lungs for extracting oxygen from the environment and delivering it to the blood?” The physiologist wants to know, “What is the oxygen conductance of the gas exchanger?” Both the morphologist and the physiologist are addressing the oxygen diffusing capacity of the gas exchange organ, and each can answer the question in his own way.
Die Aktivität von Makrophagen unterliegt einer Vielzahl von Veränderungen, die durch körperliche Belastung hervorgerufen werden können (Brodde, 1984; Michna, 1984; Michna et al., 1986; Hartmann et al., 1986; Michna und Hartmann, 1986). Führt nun ein Ausdauertraining zu einer entsprechenden Änderung der humoralen und zellgebundenen Immunlage (Liesen et al., 1976; Liesen et al., 1977; Soman et al., 1978; Bieger et al., 1980; Fehr, 1982; Lötzerich, 1982; Bieger et al., 1983; Brodde, 1984; Lehmann und Keul, 1986), so könnten in der Folge auch ultrastrukturelle Veränderungen an Makrophagen auftreten mit möglichen Heterogenitäten in ihrer Population. Der Einsatz eines Interaktiven-Bild-Analyse-Systems ermöglicht es, über eine qualitative Beschreibung morphologischer Korrelate hinaus, diese funktionellen Änderungen quantitativ zu erfassen (Twilfer und Michna, 1986). Somit könnten eine Reihe von Fragen über den Einfluß eines Ausdauertrainings auf das Makrophagen-System beantwortet werden. Diese Arbeit beschreibt die Methode der Datengewinnung.
Particles are ubiquitous in pharmaceutical drug substance and drug product. Our final crystallization steps are designed to produce particles of uniform dimensions and, failing that, we mill or micronize the powder to reduce the particle size and ensure uniformity. We routinely measure particle size and control it. It is common to set specifications for particle size distribution parameters such as the 10th, 50th, and 90th percentiles. It is a rare New Drug Application that does not have extensive presentations of particle size and its impact on drug product performance. For products designed to be inhaled (for the treatment of asthma, for instance), the limits on particle size distribution are tightly controlled. For these products, particle shape can also be an important performance attribute. It is difficult to over-emphasize the importance of particle size measurement and control to the pharmaceutical industry and to drug development. Image analysis (IA), by both optical and scanning electron microscopy, is a useful technique for determining the particle size and shape.
It is almost certain that a complete understanding of the nervous system requires a thorough knowledge of all its qualitative ‘dimensionless’ aspects (which are its components, how are they connected, what is the transmitter involved etc.) and a good deal of quantitative, 3-dimensional information about number, length, sizes, connectedness etc. of all these cells, nuclei, and major or minor bundles of connections, which are the constituents or structural components of the nervous system. It is algo rather obvious that the discovery-phase is the primary one — but discoveries of new cells, transmitters and nuclei are only first steps towards understanding functions — quantitation of all these components at the cellular or at the ultrastructural level is almost inevitable for understanding fully the complex function of their aggregate.
The structural complexity of the circulatory system exceeds the available genetic information. In the developmental process, therefore, self-organization on epigenetic levels can be postulated, which exploits information that is being generated during embryogenesis. We used mathematical tools to analyze patterns and complexity, and designed a computer model to predict geometrical and biophysical properties of bifurcating vessel systems. In particular, some boundary conditions during development, and the problem of optimality are addressed. We propose that the complexity of blood vessel formation in vivo and in sapio may be adequately described with a combination of various classical geometrical and physical concepts, supplemented by concepts of fractal geometry.
It is almost certain that a complete understanding of the nervous system requires a thorough knowledge of all its qualitative, ‘dimensionless’ aspects (which are its components, how are they connected, what is the transmitter involved etc.) and a good deal of quantitative, 3-dimensional information about number, length, sizes, connectedness etc. of all these cells, nuclei, and major or minor bundles of connections, which are the constituents or structural components of the nervous system. It is also rather obvious that the discovery-phase is the primary one — but discoveries of new cells, transmitters and nuclei are only first steps towards understanding functions — quantitation of all these components at the cellular or at the ultrastructural level is almost inevitable for understanding fully the complex function of their aggregate.
Animal bioassays by themselves can yield ambiguous results, especially in relation to human risk assessment. Three major alternates are proposed for integration in toxicology evaluations. The first is mathematical modeling and expression, viz. , statistical and quantitative structure/activity relationship (QSAR). Mathematical modeling can run indefinitely after animal experiments have terminated, and can serve as a powerful adjunct to animal experiments. Quantum mechanical analysis (QMA) can help researchers to study, on the molecular level, the interactions of chemicals and the body and to understand and predict side effects. QSAR assumes that a functional dependence exists between the observed biological response and certain physiological properties of molecules. With QMA implementation in QSAR, one can obtain reactivity characteristics in order to relate molecular structure to the observed biological activity. Stereology (morphometry) can be used to attach quantitative values to complex biological structures identified in light and electron micrographs. By integrating structural/functional data one expects to pinpoint the specific cellular responses to one or several chemicals, and even to predict genetic events from cytoplasmic changes. The second alternate is a battery of in vitro toxicity tests. For example, plasticity of synapse formation with cultured nerve cells should yield rich dividends when coupled with monoclonal antibody and recombinant DNA technology. Monoclonal antibody technology, when applied to studying nerve cell biochemistry, should be extremely useful in identifying the structure of various surface components on nerve cells. Recombinant DNA technology is likely to yield important information with regard to specific gene expression. An application of in vitro systems to teratogenecity testing has been actively pursued. The third alternate is the use of plants. Plant systems show promise for immediate use in laboratory short-term bioassays for toxicity evaluation of specific chemicals or chemical mixtures. For testing under field conditions, few test organisms offer the advantages provided by plants.
MT is primarily an intracellular protein; however, the finding that under conditions of cadmium poisoning, MT occurs in blood plasma and in urine indicates that there must be a pathway out of cells. Of course, some of the extracellular MT could originate from cell destruction. However, addition of MT-3 affects nerve cell growth indicating an extracellular role for MT. Perfusion of MT through the coronary artery quenches free radical signals and protects myocardium from postischemic reperfusion injury [1, 2] suggesting its entry in cells. MT lacks in hydrophobic amino acid residues. It seems resonable to ask: How does MT get across cell membrane and enter cells?
The microvascular bed of tissues and organs as the region of exchange of respiratory gases and nutrients is of interest both in respect to its qualitative as well as its quantitative composition.
Software anthropomorphic breast phantoms have been used in virtual clinical trials for preclinical validation of breast imaging systems. Virtual trial quality depends largely on the realism of the simulated breast anatomy. Our phantom design has been focused on the simulation of large-scale and meso-scale anatomical structures, including the breast outline, skin, and matrix of Cooper’s ligaments and tissue compartments. Realism of such a design has been confirmed in comparative studies of phantom and clinical power spectra and parenchymal texture. We present a novel method for simulating the hierarchical organization of breast tissue subcompartments, seen in detailed histological images. The subcompartmentalization introduces microstructure in breast phantoms, resulting in improved realism of phantom images. The qualitative validation of phantoms with simulated microstructure is discussed in this paper; the quantitative validation in ongoing.
Stapling of the growth plate is considered to be a simple method of correcting angular deformities of adolescents. Despite broad clinical application our knowledge of many morpholocial and biochemical details in the response of the growth plate to stapling is still deficient. This experimental investigation was performed to present a systematic documentation of short und long term mechanical effects of stapling on the structure and function of the growth zone. A study of the underlying morphological and biochemical events would contribute to a better understanding of the control mechanisms of the growth plate.
Merkfähigkeits- und Lernstörungen als wesentliche psychopathologische Symptome dementieller Syndrome lassen sich tierexperimentell an NZB-Mäusen demonstrieren (Spencer et al. im Druck; Nandy et al. 1983). Autoantikörperbildung gegen Hirngewebe scheint in der Pathogenese dieser zerebralen Funktionsstörung eine Rolle zu spielen (Lal et al. 1985; Nandy et al. 1983). Als ein mögliches morphologisches Substrat konnte von Zilles (1985) eine verminderte Nervenzellzahl in verschiedenen Hirngebieten, so auch im Hippokampus, nachgewiesen werden. Unsere neu-ropathologische Studie galt nun der Frage, ob nicht schon in einer Läsion dem Hippokampus vorgeschalteter Strukturen die primäre zerebrale Beeinträchtigung zu sehen ist. Denkbar wäre eine solche Schädigung in der parahippokampalen Regio entorhinalis, die verschiedene sensorische Afferenzen erhält und von der Efferenzen zum Hippocampus ausgehen (Van Hoesen et al. 1972, Hjorth-Simonsen u. Jeune 1972).
The purpose of this chapter is to review the capabilities and applications of more than 35 stereology programs. We will consider how computers are being used to solve several problems of data management and to identify software packages that currently offer new and improved strategies for biological stereology. The chapter is not meant to be a comprehensive review of the literature, instead references were selected to illustrate the range of software available. Section 1 gives an overview of stereology, Sections 2 (Point Counting Programs) and 3 (Digitizing Programs) describe software currently being used for collecting raw data and estimating simple stereological parameters, and Section 4 includes a discussion of several special-purpose programs that offer access to some of the more advanced methods of data analysis.
The entorhinal region is located in the rostral third of the parahippocampal gyrus. In the clearest cases, especially in young individuals, the extent of the entorhinal region can be distinguished with the naked eye due to its rough, wartlike surface, which contrasts with the smooth pial surface of the rostrally located temporal pole, medial prepiriform cortex, periamygdaloid region, and the laterally and caudally ensuing fields of the temporal isocortex. In the human brain the entorhinal region with its rough surface has a size somewhat more than a thumb nail, that is, maximally 30 mm in rostrocaudal and 15 mm in mediolateral width. Rostrally the entorhinal region terminates in a conical manner; laterally it seems to disappear in the collateral sulcus.
It is generally accepted that enteroviruses, especially coxsackieviruses of group B (types 1–5), play an important role in acute myocarditis of humans [1]. These RNA viruses, which contain a single-stranded RNA genome of positive polarity can induce dilated cardiomyopathy of acute onset or lead to life-threatening arrhythmias and sudden death.
Die bisher vorliegenden Untersuchungen zur Druckhypertrophie behandelten mäßige oder schwere Grade der Hypertrophie. Im Gegensatz dazu führt ein körperliches Training häufig nur zu einer geringen Herzhypertrophie. In der vorliegenden Untersuchung werden quantitative stereologische Untersuchungen an beiden Modellen bei vergleichbarem Grad der Herzhypertrophie vorgestellt.
Mathematical Morphology is introduced as a method Image Analysis based on set theory. Two examples are treated in detail, in order to exhibit sequences of operations. Emphasis is put on the progressive loss of information. The concept of a morphological filter is then presented. -Author
In many cases a subjective microscopic observation, completed eventually with a description and photomicrograph, is insufficient to bring out all the relevant information contained in the object. To detect changes in the course of an experiment or to be able to compare one’s findings with data from other investigators, it will be useful or even necessary to know the dimensions, the shape, the spectral properties or other characteristics of certain elements of a microscopic object. Quantificaton of such data moreover contributes to an objective description of the object.
In den anorganischen (“exakten“) Wissenschaften hat die zahlenmäßige Beschreibung von Beobachtungen eine lange und erfolgreiche Geschichte. In den Arbeiten der Schule des Pythagoras sehen wir bereits einen Höhepunkt dieses Ansatzes. In den Biowissenschaften herrschte dagegen lange Zeit eine qualifizierende Beschreibung vor, ganz besonders auf dem Gebiet der morphologischen Disziplinen. Diese Zurückhaltung wird verständlich, wenn man bedenkt, daß die zunächst zugänglichen makroskopischen Parameter breiten Schwankungen unterliegen, die vor allem durch die Abhängigkeit genetischer Informationsexpression von äußeren Faktoren bedingt sind. Erst die neuere biologische Forschung, insbesondere auf dem zellulären und subzellulären Niveau, gab einen neuen Anstoß, Beobachtungen quantitativ zu korrelieren.
The physiological importance of tissue capillary supply is generally accepted in broad terms, such as providing adequate oxygen delivery and waste removal in working muscle, delivery of substrates and removal of products in endocrine tissue, and facilitating pathologically rapid growth in tumours. However, when one looks in greater detail at the regulation and interrelationship of tissue phenotype and the microvasculature, it quickly becomes evident that our understanding is still far from complete. There is, therefore, a need for quantitative (morphometric) analyses which adequately describe the anatomical capillary bed, from which estimates of the functional capillary supply may be derived. Although new insights arise constantly, this is in fact a very old area of study. In the 17th century, Malpighi and van Leuwenhoek studied the microcirculation by direct observation, while a qualitative picture of microvascular anatomy has been available for over a century (Ranvier 1874; Spälteholz 1888; Krogh 1919). Recent reviews cover much of the important literature regarding architecture (Wiedeman 1984), adaptation (Hudlická 1984) and angiogenesis (Hudlická and Tyler 1986) in various tissues, and offer an overview of the varied techniques employed. This chapter considers the utility of various quantitative estimators of capillary supply, from which an integrated analysis at differing levels of resolution may be performed. Analytical methods for particular networks, even of larger vessels, may also be applicable in varying degrees for other tissue.
Despite their heterogeneity, bimrocks (block-in-matrix rocks) such as melanges can be systematically characterized. The strength of a bimrock is simply and directly related to the volumetric proportion of the blocks in the rock mass, which requires that volumetric block proportions and other block properties be determined. Because melanges contain blocks at all scales, a characteristic engineering dimension (Lc), such as a landslide thickness or a tunnel diameter, is necessary to describe a bimrocks mass at a particular scale of engineering interest. Block sizes range between the largest at 0.75 Lc and the block/matrix threshold at 0.05 Lc. Volumetric block proportions can be estimated from mapping and drill core and adjusted for uncertainty. Even where low block proportions do not increase the strength of a bimrock, systematic characterization will reduce expensive geotechnical design and surprises during construction.
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