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At least 1,189 records · Page 66Linked to original sources
PubMed1993

Vascular morphometry of KHT and RIF-1 murine sarcomas.

Although tumor oxygenation and vascular structure have been studied extensively, previous work has most often been qualitative in nature. To clarify underlying physiological mechanisms, a more quantitative approach is needed. The current work considers two murine tumor lines of differing radiobiological hypoxic fraction (HF), the RIF-1 and the KHT fibrosarcomas. Following intravascular injection of India ink, histological sections were prepared and quantitated in terms of anatomical blood vessel-tumor cell distance distributions and vessel diameters. Vessel diameters increased with increasing tumor volume for RIF-1 tumors, while not changing significantly for the KHT. The fraction of the tumor within a given distance of the nearest blood vessel, varied as a function of: (i) tumor line, (ii) distance from tumor surface, and (iii) tumor volume. For small-volume tumors, intertumor differences in vessel-tumor cell distances correlated with differences in radiobiological HF, while for large-volume tumors, vessel-tumor cell differences were not significantly different between tumor lines. Combining current findings with previously determined intravascular oxyhemoglobin distributions in the same two tumor lines, it was apparent that not only is a substantial portion of the tumor volume beyond the expected oxygen diffusion limits of blood vessels, but, in addition, a relatively low percentage of these vessels is capable of supplying oxygen.

Animals↗
PubMed1983

Morphometry of nuclei, nuclear envelopes and nucleoli in aging hamster cerebrum.

The neuronal nucleus and nucleolus undergo extensive dimensional and configurational changes during maturation and aging, as shown in this study of pyramidal cells of the hamster motor cortex. With maturation, the increase in nuclear perimeter length per unit nuclear area was associated with an increased amount of nuclear invaginations. With maturation and aging, there was a change in nuclear caliper shape, from spherical to very nonspherical. The number of nucleoli containing microbodies peaked first at 15 days and again at 600 days. It is concluded that area, perimeter and form factor relate to nuclear caliper shape and the presence of nucleolar microbodies. The correlated changes in these parameters appear to differentially reflect stage-specific metabolic conditions related to two critical phases: (1) an early phase (10-15 days) at the inception of configurational changes leading to maturity, and (2) a late phase (600-700 days) at the inception of configurational changes leading to old age.

Aging↗
PubMedDate not supplied

Morphometry of the human cortex cerebri and corpus striatum during aging.

The commentary is based on our results of biological aging research with the following findings: a loss of neurons cannot be found, the size of neurons and the number of synapses decrease with age, the various regions of brain react quite differently. Altogether, these results speak for "use it or lose it." However, the genetically determined decreased brain function during aging can only be inhibited, not permanently preserved.

Aged↗
PubMed1984

Effects of phosphate on calcium release, lysosomal enzyme activity in the medium, and osteoclast morphometry in cultured fetal rat bones.

The relationship between changes in medium phosphate concentration and three indices of cell-mediated resorption in fetal rat bone cultures--calcium release, the activity of the lysosomal enzyme beta-glucuronidase in the medium, and the morphology of osteoclasts--has been investigated. Bones treated with either 1 mM or 4 mM phosphate, with or without parathyroid hormone, were examined. After 2 h of culture we found the predominant effect of changes in medium phosphate to be on non-cell-mediated resorption. However, after 24 h changes in medium phosphate affected both cell-mediated and non-cell-mediated resorptive mechanisms. The 24 h effects of phosphate were not associated with either a change in the activity of beta-glucuronidase in the medium or in the area of the ruffled border of osteoclasts, but 4 mM phosphate did prevent parathyroid hormone from increasing the area of the clear zone of osteoclasts. These results imply that changes in medium phosphate alter cell-mediated resorption by affecting mechanisms that are independent of increases in beta-glucuronidase activity or changes in the ruffled border of osteoclasts but that may involve effects on the clear zone of osteoclasts.

Animals↗
PubMed1995

Facial morphometry of television actresses compared with normal women.

PURPOSE: The object of this investigation was to determine whether young women considered as beautiful differ in their three-dimensional facial characteristics from normal women of the same age and race. METHODS: The three-dimensional coordinates of 22 standardized soft-tissue facial landmarks were automatically collected in two groups of women using a noninvasive instrument. The first group consisted of 10 white television actresses selected only on the basis of their soft-tissue facial appearance ("beautiful" group); the second group included 40 healthy, white women selected according to criteria of dentofacial normality ("normal" group). The x, y, and z coordinates of the points collected on each woman were used to calculate several three-dimensional angles, linear distances, linear distance ratios, and facial volumes. RESULTS: The facial morphometric characteristics within the beautiful group were more uniform than within the normal group. On average, the beautiful women had a larger forehead, a larger middle facial third relative to the total face, a wider (left-right dimension) and less deep (anteroposterior dimension) face, a smaller nose, and a less convex face (in both the sagittal and transversal planes) than the normal women. CONCLUSION: The three-dimensional cutaneous facial characteristics of the beautiful women were significantly different from the characteristics of the normal women.

Adult↗
PubMed1993

Morphometry of intraluminal side-to-side differences in human basal cerebral arteries.

Intraindividual variability of Doppler frequencies in the basal cerebral arteries is higher than the variability in perfusion measurements. Since Doppler frequency is dependent on vessel diameter, we measured intraluminal vessel diameters post mortem. In 73 human cadavers, we measured fresh pairs of rings of the terminal internal carotid artery, the anterior and the middle cerebral artery. Mean intraluminal diameters (+/- standard deviation) for the respective vessel segments were 2.8 +/- 0.49 mm (2.72 +/- 0.49 mm), 1.61 +/- 0.37 mm (1.63 +/- 0.39 mm) and 2.10 +/- 0.38 mm (2.10 +/- 0.41 mm). The left/right ratio was 1.04 +/- 0.13, 1.05 +/- 0.35 and 1.02 +/- 0.17. Intraindividual asymmetries in intraluminal vessel diameters might be an additional factor in the interpretation of intracranial Doppler frequency measurements.

Adult↗
PubMed1981

Morphometry of nuclear pore complexes in thyroid cells during hyperplasia and involution.

Nuclear pore complexes were analyzed in freeze-fractured replicas of thyroid follicular cells of C3H mice in different physiological states. Thyroid stimulation induced a rapid and simultaneous increase of the nuclear surface and volume and of the total number of pore complexes. The numerical density (Na) of pore complexes increased at the 6th day of stimulation, but after that time the proportion of cells with an increased Na was always higher than the proportion of 3H-labelled nuclei. During thyroid involution, all the nuclear parameters, including the Na, returned to normal values. These results indicate that the total number of pore complexes and their Na are correlated with the cellular activity rather than with the cell cycle. They also suggest that 2 different mechanisms are involved in the generation of pore complexes: first, an addition of new membranes with a low density of pore complexes; later, a formation of new pore complexes in preexisting membranes. However, during involution, parts of the nuclear membranes and pore complexes in the remaining parts disappear synchronously. In freeze-fractured thyroid nuclear membranes, 2 neighbouring pore complexes were always separated by a distance of 105 nm. Clusters of pore complexes were not observed. A comparison of the distances between pore complexes and between randomly generated points never showed any significant differences indicating that pore complexes were randomly distributed.

Animals↗
PubMed1994

Mapping and computer assisted morphometry and microdensitometry of glucocorticoid receptor immunoreactive neurons and glial cells in the rat central nervous system.

By means of a monoclonal mouse immunoglobulin G2a antibody against the rat liver glucocorticoid receptor and the indirect immunoperoxidase technique, the distribution of glucocorticoid receptors in neuronal and glial cell populations was mapped in the central nervous system of the male rat. The mapping was complemented by computer-assisted morphometric and microdensitometric evaluation of glucocorticoid receptor immunoreactivity in many brain regions. The quantitative analysis allowed us to achieve for the first time an objective characterization of glucocorticoid receptor distribution in the CNS, thus avoiding the ambiguities of previous mapping studies based on subjective evaluations. In addition, a taxonomic analysis of central nervous system regions containing glucocorticoid receptor immunoreactivity was carried out utilizing the quantitative parameters obtained in the morphometric evaluation. Nuclei of neuronal and glial cells containing glucocorticoid receptor immunoreactivity were detected in a widespread, but still highly heterogeneous, fashion in the central nervous system, underlining the view that glucocorticoids can control a large number of central nervous system target cells via effects on gene expression. Many nerve cell populations have been shown to contain substantial amounts of nuclear glucocorticoid receptor immunoreactivity, whereas only a low density of glial cells, in both gray and white matter, show nuclear glucocorticoid receptor immunoreactivity. Thus, in most brain areas, the major target for glucocorticoids appears to be the nerve cells. Interestingly, an inverse correlation was found in the regional density of glucocorticoid receptor-immunoreactive nerve and glial cells, suggesting that glucocorticoids may influence a brain area either via glial cells or, more frequently, via nerve cells. The results on mapping highlight the impact of glucocorticoids in areas both traditionally and not traditionally involved in stress responses. The distribution of glucocorticoid receptor immunoreactivity also emphasizes a role of glucocorticoids in the regulation of the afferent regions of the basal ganglia and the cerebellar cortex, and of both afferent and efferent layers of the cerebral cortex. Glucocorticoid receptor immunoreactivity is widely distributed over the thalamus, probably leading to modulation of activity in the various thalamocortical pathways transmitting inter alia specific sensory information to the cerebral cortex. Many unspecific afferents to the cerebral cortex are potentially regulated by glucocorticoid receptors such as the noradrenaline and 5-hydroxytryptamine afferents, since their nerve cells of origin contain strong glucocorticoid receptor immunoreactivity. Eight brain regions involving sensory, motor and limbic areas were shown to have a similarity with regard to glucocorticoid receptor-immunoreactive parameters at the level of 95%. The density of glucocorticoid receptor-immunoreactive nerve cells appeared to be the main factor in determining such a very high level of similarity. Overall, our results emphasize that glucocorticoids may appropriately tune networks of different areas to obtain optimal integration and in this way improve survival of the animal under challenging conditions.

Adrenalectomy↗
PubMed1990

Fetal hypothalamic transplants into brain irradiated rats: graft morphometry and host behavioral responses.

This study was designed to test the hypothesis that neural implants can ameliorate or prevent some of the long-term changes associated with CNS irradiation. Using a rat model, the initial study focused on establishing motor, regulatory, and morphological changes associated with brain radiation treatments. Secondly, fetal hypothalamic tissue grafts were placed into the third ventricle of rats which had been previously irradiated. Adult male Long Evans rats received one of three radiation doses (15, 22.5, & 30 Gy) or no radiation. Three days after irradiation, 7 animals in each dose group received an embryonic day 17 hypothalamic graft into the third ventricle while the remaining 8-9 animals in each group received injections of vehicle solution (sham). Few changes were observed in the 15 and 22.5 Gy animals, however rats in the 30 Gy treatment group showed stereotypic and ambulatory behavioral hyperactivity 32 weeks after irradiation. Regulatory changes in the high dose group included decreased growth rate and decreased urine osmolalities, but these measures were extremely variable among animals. Morphological results demonstrated that 30 Gy irradiated animals showed extensive necrosis primarily in the fimbria, which extended into the internal capsule, optic nerve, hippocampus, and thalamus. Hemorrhages were found in the hippocampus, thalamus, and fimbria. Defects in the blood brain barrier also were evident by entry of intravascularly injected horseradish peroxidase into the parenchyma of the brain. Animals in the 30 Gy grafted group showed fewer behavioral changes and less brain damage than their sham grafted counterparts. Specifically, activity measures were comparable to normal levels, and a dilute urine was not found in the 30 Gy implanted rats. Morphological changes support these behavioral results since only two 30 Gy implanted rats showed necrosis in the fimbria, internal capsule, and other areas of the brain. These results suggest that grafts of fetal neural tissue exert a beneficial influence on the host brain, although the mechanism by which the implant exerts its effect is still unknown. Evidence supporting the role of trophic factors is reviewed. These preliminary results suggest a potential for tissue grafts in the treatment of CNS irradiated patients.

Animals↗
PubMed1995

Blood-spinal cord barrier function and morphometry after single doses of x-rays in rat spinal cord.

PURPOSE: The effects of irradiation on blood-spinal cord barrier (BSCB) function and ultrastructure were evaluated using a rat spinal cord model. METHODS AND MATERIALS: Rats received a single dose of 25 Gy to the cervical spinal cord (C2-T2). At various times following irradiation and before the onset of paralysis, BSCB function was assessed using horseradish peroxidase (HRP) as a vascular tracer, and barrier-related structural changes in the capillaries were evaluated using morphometric techniques. RESULTS: Focal extravasation of HRP was seen at 93 days after irradiation, and extensive extravasation was apparent by 114 days in white matter, but not in gray matter. At 93 days, pathologic changes apparent by light microscopy were very minor in the white matter of the irradiated segment. By 107 days, myelin beading, Wallerian degeneration, edema, and histiocytes were apparent in white matter, and these features became increasingly prominent over the following weeks. No noteworthy changes were seen in gray matter at these times. Electron microscopic examination showed that, during the first 93 days following irradiation, more than half of the endothelial cells in white matter had disappeared (p < 0.05). In terms of the putative vascular pores, no abnormalities in endothelial junctions (the presumed small pore) were found, but there was an increase in the density of endothelial vesicles (a putative form of the large pore) in irradiated white matter (p < 0.001), but not in gray matter. Pericytes, thought to act as a second line of defence in the blood-brain barrier, increased in size but not in number in the irradiated white matter of the spinal cord. CONCLUSION: We suggest that radiation damage to endothelial cells, which form the BSCB prior to the onset of neurological deficit, may play an important role in the pathogenesis of white matter necrosis.

Animals↗
PubMed1994

Morphometry and distribution of displaced dopaminergic cells in rat retina.

The majority of dopaminergic (DA) cells, labeled by tyrosine hydroxylase (TH) immunohistochemistry, are located in the amacrine cell layer (i.e., the innermost sublayer of the inner nuclear layer) in the rat retina. We describe a small population of DA cells, observed in retinal wholemounts, that are displaced to either the inner plexiform layer (DAIcs) or the ganglion cell layer (DAGcs). Contrary to some other species, such cells are few in number in the rat retina. Their systematic study was made in young and adult retinas by retinal mapping, camera lucida drawing, and computer-aided three-dimensional reconstruction. Located predominantly in the superior temporal quadrant, they are observed as soon as the second postnatal day. Most of the morphometric parameters studied were not significantly different between the two types of displaced DA cells, despite the characteristic appearance of interstitial cells. Two hypotheses are proposed for the origin of their displacement: either it is accidental or programmed. Our results favor the former possibility.

Aging↗
PubMed1993

Morphometry of the human heart in the second and third trimesters of gestation.

The growth of the heart was studied in 56 human fetuses ranging from 14 to 38 weeks (23 female and 33 male) using the following measurements: cardiac length and width, aortic and pulmonary artery internal diameters, right and left anterior ventricular wall thickness. Relationships between the fetal cardiac data and crown-rump length were explored by allometry and linear regression analysis. The present study confirmed that the heart increases with high growth rates and positive allometry during prenatal life. Statistically different growth rates were found comparing female with male fetuses (sexual dimorphism): (a) in the third trimester (P < 0.001, except for the cardiac length and the left ventricular wall thickness), (b) considering fetuses of the second and third trimesters together (only for cardiac width, P = 0.0015). In these circumstances the female fetuses had the greatest growth rates. The length and the width of the heart are diameters easily obtained in the ultrasonographic four-chamber view of the heart in the last two trimesters of gestation. Therefore, these data can be analyzed by non-invasive methods and are useful for prenatal detection of congenital heart disease.

Biometry↗
PubMed1986

Organ of Corti surface preparations for computer-assisted morphometry.

This paper describes a relatively rapid method (67 h) for producing surface preparations of the organ of Corti that are suitable for a computer-assisted morphometric analysis of cochlear hair cells. On day 1, a cochlea was fixed in OsO4, dehydrated in ethanol and infiltrated with an Epon-like plastic (Medcast). On day 2, the Medcast within the cochlea was polymerized at 60 degrees C in an oven. On day 3, the complete organ of Corti was dissected into approximately 20 segments which were trimmed and mounted on a slide in Medcast. Two 400 mesh transmission electron microscope grids are mounted at the apical and basal ends of the organ of Corti. These grids served as reference points for the establishment of an independent X, Y coordinate system on the slide by a computer-assisted light microscope. The segments were permanently attached to the slide by polymerization of the Medcast at 60 degrees C for approximately 15 h. At the beginning of day 4, the organ of Corti surface preparation was ready for examination by light microscopy or could be further sectioned and examined by transmission electron microscopy.

Animals↗
PubMed1995

Recent developments in DXA. Quality of new DXA/MXA-devices for densitometry and morphometry.

The introduction of new devices demands the assessment of their capabilities in established terms. The accuracy, reproducibility and spatial resolution of in vitro (phantom) osteodensitometric and morphometric measurements of QDR 2000 Plus and EXPERT are presented. Design details of these DXA/MXA-devices are listed and discussed in combination with the data acquired in the test measurements and calculations. The image quality will improve with further software developments. The long-term reproducibility and in vivo reliability remains to be evaluated.

Absorptiometry, Photon↗
PubMed1995

Morphometry in temporal lobe epilepsy.

We demonstrate a method for quantitating changes in volume and morphology of the temporal lobe in epilepsy. The temporal lobes of 10 neurologically normal subjects and six subjects with well defined left-sided mesial temporal epilepsy were studied. From high resolution T1-weighted magnetic resonance images, the grey and white matter were manually segmented over a predetermined extent. The volumes of the grey and white matter were determined. Using the segmented images, the grey matter/CSF surface and the white matter/grey matter surface were reconstructed, allowing estimates of the surface area and calculation of indices of curvature for the two surfaces. The index of curvature was calculated for each vertex of a polygonal mesh that was fitted to the surfaces. An index of grey matter thickness (grey matter volume/white matter surface area) was also calculated. There was a significant bilateral decrease in the total volume (p < .01), grey matter volume (p < .001) and grey matter thickness index (p < .05) in epileptic subjects. In addition, there was a bilateral decrease in white matter surface area (p < .05) and a small left-sided decrease in white matter volume (p < .05) in epileptic subjects. The average distributions of indices of curvature for both surfaces differed significantly (p < .05) between normal and epileptic subjects. In the grey matter/CSF surface of normal subjects, a large peak corresponding to surface concavity was present. The amplitude of this peak was significantly lower in epileptic subjects (p < .05 for the right hemisphere; p < .001) for the left hemisphere).

Adult↗