Hippocampal capillaries in different age groups of chronically ethanol-intoxicated rats. Morphometrical studies.

The influence of chronic ethanol intoxication on the terminal vascularization of particular hippocampal fields and layers was investigated in different age groups of rats. Thirty-six male Wistar rats aged 6 weeks were used in the study. For twelve months 24 of them drank only 25% ethanol--12 starting at 6-week-age and 12 at 3-month-age. The control group of 12 rats drank only water. As an effect of long-term ethanol exposure on hippocampal capillaries we observed the increase in the terminal vessel diameter and the decrease in microvascular length, surface, and volume densities. These changes varied between different age groups and between particular hippocampal regions. The observed age and regional differentiation of ethanol-related microvascular changes did not correlate well with the damaging effects of alcohol on corresponding neuronal elements, which emphasizes the very complicated pathogenesis of ethanol-induced injuries.

Interstitial tissue fraction. The prognostic marker in membranoproliferative glomerulonephritis in children.

OBJECTIVE: To explain the differences in the clinical course of membranoproliferative glomerulonephritis (MPGN) in children and to find some prognostic markers at the disease onset that correlate with the disease outcome. STUDY DESIGN: We reviewed clinical histories and laboratory findings, reexamined kidney biopsies performed at the disease onset and evaluated volume relations between kidney components in children with the diagnosis of MPGN. RESULTS: Children were divided into three groups based on their final clinical status: I. children without features of active nephropathy, II. children with persistent nephropathy, and III. children who died of kidney disease and those who had chronic renal insufficiency. Reevaluation of kidney biopsies led to a change in the histopathologic diagnosis in several cases in all three groups. Morphometric analysis showed increasing interstitial tissue volume from group I through group III in MPGN and other forms of glomerulonephritis diagnosed after reevaluation. All the morphologic, clinical and laboratory features estimated by means of multivariate analysis of variance showed statistically significant individual characteristics of each group defined by clinical outcome. CONCLUSION: Increased interstitial tissue volume in the kidney biopsy at the disease onset is a negative prognostic factor in MPGN.

Pericapillary and distant axon terminals in the nuclei of the cat amygdala: a morphometric study.

According to some ultrastructural studies, the pericapillary axon terminals in the central nervous system (CNS) are functionally connected with the capillary vessel wall. Thus, it may be expected that the population of pericapillary axon terminals will be morphologically distinct from the terminals at a further distance from the capillary walls. To test this hypothesis, morphometrical analysis of 3,048 axon terminals was performed, comparing terminals situated in the close vicinity of the capillary vessel with those at a distance from the vessels in the lateral, basal, medial, central and cortical nuclei of the amygdaloid body of eight cats. The cross-sectional area and circumference of each identified axon terminal profile were measured, and the shape of synaptic vesicles and the presence of synaptic contacts and granular vesicles were recorded. The statistical evaluation of results was performed by means of the Newman-Keuls' test, Wilcoxon's test, Fisher's contingency-table test and the test for two coefficients of structure. The morphometric examination revealed two ultrastructurally distinct groups of axon terminals, pericapillary and distant terminals, in all the nuclei of the amygdaloid body. The differentiating features were the shape of the synaptic vesicles, the number of synaptic contacts, and the size of the axon terminals. These results further support the hypothesis of a functional connection between axon terminals and the capillary vessel wall in the CNS.

Morphometrical study of rat hippocampus. Light-microscopic features.

The purpose of our study was to evaluate morphometrical parameters of the particular hippocampal fields and layers in rats. Studies were performed on 72 semi-thin Epon specimens, representing the CA1, CA3, CA4 sectors, and dentate gyrus. The material was obtained from 12 adult male Wistar rats fixed by perfusion. The following parameters were examined: size of the terminal vessels; length, surface, and volume densities of the terminal vascularization; profiles and numerical densities of the neurons; size of the neuronal nuclei and distribution of nuclei size classes. The results were verified statistically. The analysis of terminal vessels system showed various differentiation between the layers in all the examined hippocampal fields. The vessels were smaller and their length density was higher in the pyramidal or granular layers than in the polymorphic or molecular ones. The comparison of terminal vascularization among the fields showed some differences only within the pyramidal and granular layers. The smallest terminal vessels were found in dentate gyrus, the biggest - in the CA4 sector, which was also separated by the lowest length density of terminal vascularization. Neuronal density and nuclear size significantly separated each of the analyzed hippocampal fields.

Effects of vitamin D on aortic smooth muscle cells in culture.

Earlier investigations on vitamin-induced experimental atherosclerosis in rats suggested that smooth muscle cells (SMCs) play a pivotal role in development of these vascular abnormalities. This study demonstrates the effects of vitamin D (ergocalciferol) on SMCs of rat aorta in tissue culture. SMCs were obtained from aortas of newborn rats by enzymatic digestion and maintained for 6 wk in primary culture with vitamin D (1.2 nm) in the culture medium. The effects of vitamin D on SMCs, as compared with control SMCs cultures, were evaluated by light and electron microscopy. Growth of SMCs was characterized by cell counting, measurement of DNA and protein content, and by analysis of the nucleolar organizing regions. Vitamin D had no effect on proliferation of SMCs but stimulated synthesis and intercellular deposition of elastic fibres and had a stabilizing effect on the musculo-elastic multilayer formed by the cultured cells. In addition, it prevented degeneration of SMCs, with long-term preservation of the typical phenotype in primary culture.

Pathogenesis of heart myofibril lesion in experimental vitamin D-induced cardionecrosis.

Multifocal cardionecrosis has been produced in rats by treatment with 3 x 100,000 iu vitamin D3 (calciol). The effects of hypervitaminosis D on rat heart myofibril structure and total protease activity was investigated. Proteolytic enzyme activity of heart muscle homogenate was determined in two independent ways, and was approximately two times higher in the necrotic heart homogenate than in the control rat heart. Electron microscopic examinations showed structural derangements. Myofibrils isolated from necrotic heart exhibited significant changes of ultrastructure in the region of Z-line and I-band. Myofibril enzyme activity (Mg(2+)-ATPase) measurements demonstrated functional deficits as well. Under different conditions of myofibril isolation, it was shown that both ultrastructural and enzymatic lesions appear to be mediated by calcium-activated proteolytic enzymes operating in situ. Our results indicate that the increased proteolytic activity caused by vitamin D treatment leads to the in situ damage of proteins of the heart contractile system.

Comparative morphometric analysis of terminal vascularization of hippocampal CA1 and CA3 sectors in Mongolian gerbils.

Comparative morphometric analysis of terminal vascularization (vessels with a diameter lower than 12.5 microns) in the ischemia-sensitive sector CA1 and the ischemia-resistant sector CA3 of Ammon's horn in Mongolian gerbils was performed. Basing on numerous computer-counted parameters characterizing the terminal vascular network in both hippocampal sectors and its relationship to the surrounding tissue, it was shown that a number of capillary vessels, their average diameter, and exchange and flow surfaces were to a statistically significant degree lower in the pyramidal layer of the CA1 sector as compared with those in CA3 sector. The number of pyramidal neurons in the pyramidal layer, counted per surface unit was in sector CA1 higher than in sector CA3. The obtained data indicate clearly an angioarchitectonically dependent lower microvascular capacity of sector CA1. However, these differences do not indicate per se a leading role of the vascular factor in the pathomechanism of selective vulnerability to ischemia. They may be a factor facilitating neuronal damage evoked by the excitotoxic action of glutamate, observed in CA1 sector as a result of forebrain ischemia.

Terminal vessels of dentate gyrus in chronically alcohol-intoxicated rats.

Quantitative changes in the microvasculature of the central nervous system of the rat following chronic ethanol intoxication were studied. For 6 months, 12 rats drank only 25% ethanol and eight control rats only water. After fixation by perfusion, semithin sections of dentate gyrus were obtained. In each one, semiautomatic measurements were made of the length, surface, and volume densities, and the mean area of a terminal vessel cross-section and the results were evaluated statistically. Chronic ethanol intoxication caused an increase in the length and surface density, a decrease in the mean cross-sectional area, whereas the volume density of terminal vessels was unchanged. These results show that the reduction of the mean surface area of terminal vessels after prolonged ethanol intoxication is compensated by the increase of other morphometrically measurable parameters, i.e., length and surface density. As a consequence of these alterations, the volume density remains unchanged. The results indicate great reactivity of the microvascular system of the dentate gyrus in chronically ethanol-intoxicated rats.

Hepatitis B virus-associated glomerulonephritis: electron microscopic studies in 98 children.

Ninety-eight children with glomerulonephritis concomitant with hepatitis B surface HBs antigenemia were studied, the antigenemia being first documented at the clinical onset of glomerulopathy. Initial diagnoses, based on examination of the paraffin sections, varied, membrano-proliferative, mesangial, and membranous glomerulonephritis being most frequently considered. However, electron microscopic examination showed that 77 children had a uniform type of glomerulopathy, irrespective of the light microscopic appearance. This type was diagnosed as secondary membranous glomerulonephritis. The clinical course of this nephropathy was relatively indolent and short. Moreover, in many children, elimination of some hepatitis B virus (HBV) antigens from the circulation was also associated with clinical remission of glomerulopathy. The remaining 21 children with HBs antigenemia had various morphological forms of glomerulonephritis, these being similar to their idiopathic counterparts in both morphology and clinical course. The distinct clinical and morphological picture of secondary membranous glomerulonephritis with HBs antigenemia occurring in 77 of 98 children supports the hypothesis that HBsV-associated glomerulonephritis is of the secondary membranous type. Thus, we conclude that in children HBV antigenemia associated with glomerulonephritis other than secondary membranous is coincidental.

Calcium content of serum and myocardium in vitamin D-induced cardionecrosis.

The dynamics of calcium content alterations in serum and heart muscle in relation to vitamin D-induced cardionecrosis was the aim of the experiment performed on female Wistar rats killed at different times after one or two intraoral doses of 100,000 IU of vitamin D. Calcium concentration in the serum showed great individual variability, although the mean value was significantly elevated after 22 h following one dose and after 2 h following two doses of vitamin D. In the heart muscle the mean calcium content increased 72 h after one dose and 24 h after two doses of 100,000 IU of calciol, but in individual rats the increase of Ca concentration was observed as early as 30 h after one dose, in some it was normal even after 144 h of two doses and varied between individual rats 20-30-fold. The degree of cardionecrosis showed great variability among rats treated with the same dose of calciol and at the same phase of the experiment. Cardionecrosis was always preceded by great accumulation of calcium in the heart muscle and its extent was in direct correlation to the amount of calcium in the tissue, regardless of the dose of calciol and phase of the experiment.

Effects of ethanol on the development of experimental atherosclerosis and cardionecrosis in rats.

The influence of chronic ethanol intoxication upon vitamin D-induced damage of cardiovascular system in rats was examined. Eighty rats, divided into 16 groups according to sex and age, were intoxicated with ethanol as the only source of liquid. Control rats drank water only. After 6 months of ethanol intoxication, part of ethanol and part of water-drinking rats received 3 x 100,000 IU vitamin D/rat, in order to induce atherosclerosis and heart muscle necrosis. The results of the described experiment revealed that the degree of circulatory system damage after chronic ethanol intoxication and vitamin D treatment was dependent on the age of the animals at the beginning of the experiment. Ethanol intoxication intensified vitamin D-dependent heart muscle necrosis in young individuals. In old rats chronic alcohol intoxication diminished atherosclerosis induced by vitamin D.

Pathology and ultrastructural characteristics of a hypomelanotic variant of transplantable hamster melanoma with elevated tyrosinase activity.

A spontaneous, hypomelanotic variant (MI) of the highly melanotic transplantable hamster melanoma of Bomirski (Ma) is the subject of this report. Tyrosinase activity is 2-3 times higher, but melanin content significantly lower than in the parental Ma melanotic melanoma. Acid phosphatase activity is similar in both, but beta-glucuronidase and aryl-sulfatase A are 2-3 times higher in the hypomelanotic variant. Transplanted MI melanomas grow more slowly than the parental tumor, but metastasize with similar incidence and localization. Hypomelanotic variant melanoma cells, even those in grossly nonnecrotic parts of the transplants, show signs of low viability like swelling of the cytoplasm or cellular condensation, and disintegration. Autophagic vacuoles are numerous. They appear to be formed by enclosure of a portion of cytoplasm by cisternae of smooth endoplasmic reticulum or trans-Golgi network. These limiting cisternae contain tyrosinase as evidenced by deposition of electron dense reaction product on incubation with tyrosine or DOPA. Other sites of ultrastructural tyrosinase reaction are melanosomes and the smooth-surfaced cisternae and vesicles of the trans-Golgi network. We postulate the low cell viability, associated with autophagosome formation, is the cause for the growth retardation of the MI variant, and that the lower melanin content of these tyrosinase-rich cells is due to sequestration of a substantial portion of newly synthesized enzyme into autophagic vacuoles before it has the chance of being incorporated into melanosomes.

Henoch-Schönlein nephritis in children--a clinicopathological study.

36 children with Henoch-Schönlein nephritis had their renal biopsy specimens studied by light and electron microscopic and immunofluorescence antibody techniques. Though no pathognomic changes were found the histological picture was characteristic. The severity of histological changes correlated well with the clinical manifestation and disease persistence. IMF studies showed characteristic mesangial IgA staining. The most prominent ultrastructural feature was segmental mesangial and subendothelial deposits with basement membrane changes. The amount of deposits was a good exponent of disease activity-children with few deposits recovering shortly. In spite of long duration, the outcome after an average 4 year follow-up was good, the majority of children having improved and renal insufficiency developing rarely. Renal biopsy is essential for an estimation of severity of renal disease and enables prognosis of disease persistence and long term outlook.

The respiration and calcium content of heart mitochondria from rats with vitamin D-induced cardionecrosis.

Mitochondria were isolated from the heart and skeletal muscle of rats treated with three consecutive daily doses of 100 000 i.u. of calciol (cholecalciferol; 'vitamin D3'). On the fourth day after the last dose, cardiac necrosis developed. At that time mitochondria isolated from heart displayed a 10-fold higher Ca2+ content and a 6-fold lower respiratory rate with pyruvate-plus-malate as substrate as well as with other NAD-dependent substrates. No decrease in respiratory rate with succinate as substrate was observed. EDTA (5 mM) added to the medium during the isolation procedure restored both the high respiratory rate with pyruvate + malate and the low Ca2+ content of the heart mitochondria. The addition of 1 mM-CaCl2 to the medium in which a healthy (control) rat heart had been homogenized caused the same impairment of the mitochondria as did calciol treatment of the animals. No changes of mitochondria isolated from skeletal muscle were observed in rats treated with calciol. It is concluded that the heart mitochondria in vivo fail to accumulate Ca2+ from the cardiac cell overloaded with Ca2+ as the consequence of calciol treatment. Mitochondrial Ca2+ accumulation occurs during the isolation procedure unless an appropriate amount of chelating agent is added to the homogenization medium. The implication of these findings for the biochemical sequence of events in the calciol-induced cardiac necrosis is discussed.