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PubMed1980

Morphometry of astrocyte and oligodendrocyte ultrastructure after portocaval anastomosis in the rat.

The ultrastructure of astrocytes and oligodendrocytes was investigated in rats 10 days, 30 days, and 10 weeks after portocaval anastomosis (PCA). Cell and nuclear sizes were measured by planimetry on randomly sampled cells magnified X 24,000. The volume fractions of mitochondria, glia fibrils, and lipofuscin granules were measured in astrocytes by electronic image analysis. The mitochondrial profile area distribution and oligodendrocyte mitochondrial content were likewise estimated. All PCA animals had an increased astrocyte cell and cytoplasmic area, and after correction for cytoplasmic edema all groups had an enhanced mitochondrial fraction and mitochondrial number. The mitochondrial sizes were increased in all PCA groups. The mitochondrial profile area distribution curves did not suggest more than one group of mitochondria. All PCA groups had increased fractions of lipofuscin granules and glia fibrils. The oligodendrocytes had a slight fall in cell, nuclear, and cytoplasmic area after 30 days of shunting, and the mitochondrial fraction was diminished. After 10 weeks of PCA, all changes were reversed to normal values. It is concluded that the astrocytes are the active cells in the brain metabolism of ammonium. The oligodendrocytes seem to be dependent on neuronal integrity and do not contribute to the brain ammonium metabolism. The increase in astrocyte lipofuscin granules content may be explained by a beginning neuronal loss.

Animals↗
PubMed1977

Glial and nerve cell changes in rats with porto-caval anastomosis.

Nuclear size and density were determined in brain regions with different glial--neurone composition in rats up to 35 weeks after porto-caval anastomosis. In the white matter, i.e. corpus callosum, both the total cell count and the percentage of astrocytes and oligodendrocytes were unchanged. In the corpus striatum, where the glial/neurone ratio is about 1, the number of nuclei registered as astrocytes increased, and after 35 weeks astrocytes comprised 29% of glial cells (compared with 15% in controls). However, the number of oligodendrogial nuclei decreased simultaneously, leaving the total glial number unchanged. In the animals with longest experimental period there was a 15% loss of neurones. In a region with higher glial/neurone ratio, i.e. the Purkinje cell layer, the neurones showed a similar reduction, whereas the number of Bergmann astrocyte nuclei increased less than striatal astrocytes. A small group of animals with pronounced signs of encephalopathy had a higher loss of neurones and, furthermore, the glial number in corpus striatum and callosum was reduced, due to loss of oligodendrocytes. Despite the use of perfusion fixation, the size of astrocyte nuclei increased, this was reversible, as only slight changes were seen after 35 weeks. A possible explanation of the increase in astrocyte nuclear count and decrease in oligodendroglial count could be that nuclei normally considered to be oligodendroglial are transformed into nuclei with morphological characteristics of astrocytes.

Animals↗
PubMed1982

Automated image analysis of glioblastomas and other gliomas.

Tumours of the neuroglia, 172 in all (50 glioblastomas, 65 fibrillar and gemistocytic astrocytomas, 26 pilocytic astrocytomas and 31 oligodendrogliomas), were studied by automated microscopic picture analysis. Thirteen morphometric and densitometric parameters of the tumour cell nuclei as well as two mitotic parameters were determined on 4 micrometers thick Feulgen slide preparations. The correlation of the results with subjectively established grade of malignancy was examined. A close correlation was found between almost all morphometric-densitometric nuclear parameters and the morphologically established behaviour of the tumours under study. Based on these results both the method of automated microscopic picture analysis and the selected parameters have been assessed as efficient for the evaluation of the behaviour of glial tumours. The results are readily reproducible and can be obtained without requiring much time. An other advantage of this method is the use of histological preparations, which allows a comparison of the overall structure of the tumour as well as a pinpointed examination of those regions that are representative of the tumour. Subjective grading of glial tumours has been greatly objective by automation.

Adolescent↗
PubMed1988

Morphometric analysis of hepatocellular carcinoma.

In order to characterize the cytological features of highly differentiated hepatocellular carcinoma (HCC), a comparative morphometric study was made by observing 30 cases of HCCs and controls (normal, cirrhotic, and atrophic livers). Among trabecular HCCs, normotrabecular subtype (1-2 cell thick cell plate) usually showed minimal cytological atypism and was categorized as well or highly differentiated HCC. Using an image analyzer, the following 4 parameters were applied to quantitate the hepatocyte changes: mean cell size (C), mean nuclear size (N), nucleocytoplasmic (N/C) ratio and a coefficient of variance (CV = index of anisokaryosis). In normotrabecular HCCs, C was slightly but significantly reduced when compared with normal and cirrhotic livers (t-test: p less than 0.005). The value was further reduced in mid- and macrotrabecular HCCs. Normotrabecular HCCs showed almost the same N value as normal and cirrhotic livers but displayed significantly a higher N/C value than those of controls (t-test: p less than 0.001). The N/C ratio became even greater in other types of HCCs. While CV was relatively constant in other HCC groups and controls, it was extremely high in the pleomorphic type of HCC and liver cell dysplasia. The results indicated that a reduction in C and increase in N/C ratio, which appear as "nuclear crowding" in histological specimens, actually occurs in well differentiated HCC. For the histologic diagnosis of well differentiated HCC, it would be very important to examine liver specimens with these observations in mind.

Atrophy↗
PubMed1977

Glomerular size and structure in diabetes mellitus. II. Late abnormalities.

A study of autopsy kidney material from six long-term diabetics and four controls was performed in order to elucidate the mechanism of the glomerular enlargement in long-term diabetics. The volume and the severity of the glomerular lesions were measured in each of a number of randomly selected, open glomeruli. The relative amount of solid material was taken as an expression of the severity of the glomerular lesion. In the long-term diabetics the volume of open glomeruli was almost doubled compared to that of controls and in the individual subject the enlargement was found to be inversely related to the relative amount of solid material in the glomeruli. This indicates that the enlargement of open glomeruli in long-term diabetics is due to a compensatory hypertrophy rather than to the excessive deposition of basement membrane material. The number of nuclei per open glomerulus was increased in long-term diabetics, but nuclear size was unchanged. Most of the long-term diabetics had a large number of occluded glomeruli and the individual, relative number of such glomeruli correlated closely both with the duration of diabetes above 15 years and the concentration of creatinine in serum. It is concluded that the destruction of glomeruli due to diabetic microangiopathy is compensated for some years by hypertrophy of the least affected glomeruli. This compensatory hypertrophy of glomeruli might well account for the preservation of renal funtion in long-term diabetics for a number of years despite the progressive basement membrane lesions of diabetic microangiopathy.

Adult↗
PubMed1992

Prognostic factors in WHO grade 2 transitional-cell bladder cancer (TCC); a novel two-grade classification system for TCC based on mitotic index.

A retrospective histological analysis has been carried out on 537 cases of transitional-cell bladder carcinoma, followed-up over a period of 9 years. In the first part of the study WHO grade 2 tumours were analysed and a number of independent factors predictive for survival identified. In a multivariate analysis the T category and M/V index (number of mitotic figures/mm2 neoplastic epithelium) were the most important prognostic factors. In a subsequent analysis of the whole series of 537 cases, overall the M/V index was not as important in predicting survival as the stage of the tumour. However, in superficial tumours (Ta-T1) subsequent analysis showed that the M/V index alone could be used to predict survival.

Aged↗
PubMed1982

Structural dissimilarities in different regions of the pineal gland of Pirbright white guinea-pigs.

In the present study, the proximal, intermediate and distal parts of dumbbell-shaped pineal glands of Pirbright White guinea-pigs were investigated with respect to structural dissimilarities. The most conspicuous difference was that while in the proximal part the pinealocytes were arranged in a random fashion, the intermediate and distal regions, except a small ventral area in the latter, exhibited a prominent follicular arrangement of the pinealocytes. Concretions were restricted to the subcapsular region of the intermediate part, whereas cells with hyperchromatic nuclei increased in number in an anterior-posterior direction. In males, pinealocyte nuclear size did not differ significantly in the regions investigated, whereas in females the karyometric results were much more heterogeneous. Exposure of male guinea-pigs to continuous illumination for 45 days resulted in (i) a 25% decrease of pineal volume, the intermediate area being relatively little affected, (ii) an increase in the number of follicles and (iii) a decrease in pinealocyte nuclear size, especially in a ventral zone of the proximal part of the pineal gland.

Animals↗
PubMed1984

Day/night changes of pineal gland volume and pinealocyte nuclear size assessed over 10 consecutive days.

Previous studies aimed at elucidating day/night changes of pineal gland size and pinealocyte nuclear volume have yielded contradictory results. The aim of the present investigation was to examine the above parameters over a period of 10 successive days, at 6-hour intervals under a lighting regimen of LD 12:12 (7 a.m. to 7 p.m.). It was found that changes in pineal gland volume could not be correlated with the light/dark phases; instead, a rhythm with a two-day period was encountered. Pinealocyte nuclear volume, by contrast, showed clear circadian changes, exhibiting troughs during photophase and peaks during scotophase. In this experimental series, the karyometric results conformed to the melatonin forming rhythm in the rat pineal gland as reported in the literature.

Animals↗
PubMed1989

Intracerebral subependymomas. Clinical and neuropathological analyses with special reference to the possible existence of a less benign variant.

The frequency of asymptomatic subependymomas was 0.4% in 1,000 serial routine necropsies and 0.7% in symptomatic subependymomas from 1,000 serial surgical specimens of intracranial neoplasms. Among patients with subependymoma (7 symptomatic and 4 asymptomatic), we found 3 cases of marked nuclear polymorphism (NP) in biopsy specimens. The subjective NP was objectively quantified by computer-assisted morphometry, by which a significant difference in nuclear size between these three cases and other cases (p less than 0.005) was revealed. This morphological characteristic correlated with the results of DNA-analysis by flow fluorescence cytometry (FFCM): subependymomas with NP demonstrated higher S and G2/M phases in a diploid pattern than other benign gliomas of our series. From the clinical data including prognosis, however, no remarkable difference was found between the NP group and other groups. The possible existence of less benign variant should be considered in the diagnosis and treatment of subependymoma.

Adult↗