Aspirin and heparin prevent hepatic blood stasis and thrombosis induced by the toxic glycoprotein Bolesatine in mice.

Bolesatine is a toxic glycoprotein isolated from Boletus satanas Lenz, which inhibits protein synthesis in vivo and in vitro. The LD50 (24 h) is 1 mg /kg bw (i.p.), in mice and rats. When given i.p. to mice (0.1 - 1.0 mg/kg bw) bolesatine induced thrombi and blood stasis in the liver, 5 - 21 h after injection, and modifications of the number of blood corpuscles in peripheral blood. These effects were efficiently reversed by aspirin, ticlopidin and heparin (as attested by histology and electron microscopy) which however failed to prevent death in animals given lethal doses. Together, these results showed that the death of bolesatine poisoned animals given high doses, was rather due to a combination of thrombosis and other toxic effects. In addition, they suggest that these antithrombotic drugs may overcome cases of human poisoning, with low exposures of this boletus, showing a hypertension probably due to mechanical obstruction which resists normal therapy.

Ultrastructure of human Kupffer cells maintained in culture.

Sinusoidal cells were isolated by collagenase perfusion and metrizamide gradient centrifugation, from liver resected for partial hepatectomy performed under warm ischemic conditions. Kupffer cells were then separated from this population by centrifugal elutriation. Isolated Kupffer cells showed good viability, with the typical features of Kupffer cells and were engaged in the endocytosis of foreign particles. They showed numerous morphological criteria of activation. However, cultured Kupffer cells were no longer in an activated state. Kupffer cells were preserved in maintenance cultures for 2 weeks. Purity of these cultures was to 93-97%. During culture, Kupffer cells retained their ultrastructural characteristics and were active in the endocytosis of latex beads and opsonized zymosan particles. It is thus possible that partial hepatectomy performed under warm ischemia could provide valuable material for the study of Kupffer cells in vitro.

Modifications of the sinusoidal barrier in a model of postsinusoidal hypertension in the rat. An ultrastructural study of endothelial cells.

Sinusoids and sinusoidal cells were examined by light and electron microscopy, using a rat model of postsinusoidal hypertension. One month after partial ligation of the vena cava (PLVC) above the hepatic veins, subcapsular hemorrhagic areas were visible with proliferation of hepatic veins; in non hemorrhagic areas, sinusoidal congestion was found. Postsinusoidal hypertension led to a significant increase in sinusoidal volume and to major abnormalities of the endothelium such as endothelial processes and pouches with numerous diaphragmed fenestrae; some red blood cells could be seen in these pouches. Endothelial cells sent out processes in between hepatocytes. Complete and incomplete pseudo-neolumens were found near sinusoids. Numerous Kupffer cells were located either in the sinusoidal barrier or infiltrating the Disse space close to extravasated red blood cells and perisinusoidal cell processes. 18 months after PLVC, lesions were much the same except for the presence of red blood cells in the Disse space.

Lynxacarus radovskyi infestation in a cat.

An adult domestic short-hair cat from south Texas was examined because of excessive dandruff on the back, neck, thorax, and hind limbs. Removal of a few hairs for microscopic evaluation revealed Lynxacarus radovskyi, the cat fur mite. The small (< 0.5 mm) mite could be readily identified by its laterally compressed body and its characteristic grasping of the hair shaft between the gnathosoma and palpi. Thus far, this mite has been identified as a parasite of cats in warm, humid environments. The number of parasites and apparent discomfort in cats varies considerably, from massive infestation with little discomfort to few mites and marked pruritus. Acaricides that are effective against other ectoparasites of cats apparently are effective in controlling L. radovskyi.

Inflammation of bronchial smooth muscle in allergic asthma.

BACKGROUND: Recent observations in asthma suggest that bronchial smooth muscle is infiltrated by inflammatory cells including mast cells. Such an infiltration may contribute to airway remodelling that is partly due to an increase in smooth muscle mass. Whether muscle increase is the result of smooth muscle cell hypertrophy remains controversial and has not been studied by ultrastructural analysis. A morphometric analysis of airway smooth muscle (ASM) was undertaken in asthmatic patients using electron microscopy to examine the interactions between ASM cells and inflammatory cells. METHODS: ASM specimens were obtained from 14 asthmatic subjects and nine non-asthmatic controls undergoing fibreoptic endoscopy. Inflammatory cell counts were assessed by immunohistochemistry, and ultrastructural parameters were measured using electron microscopy in a blinded fashion on smooth muscle cells and inflammatory cells. RESULTS: ASM from asthmatic patients was infiltrated by an increased number of mast cells and lymphocytes. Smooth muscle cells and their basal lamina were thicker in asthmatic patients (9.5 (0.8) and 1.4 (0.2) microm) than in controls (6.7 (0.4) and 0.7 (0.1) microm). In asthmatics the extracellular matrix was frequently organised in large amounts between ASM cells. Myofibroblasts within smooth muscle bundles were only observed in asthmatics, some of them displaying a close contact with ASM cells. CONCLUSION: In asthma, airway myositis is characterised by a direct interaction between ASM cells and mast cells and lymphocytes. Smooth muscle remodelling was present, including cell hypertrophy and abnormal extracellular matrix deposition moulding ASM cells.

[Ultrastructure of rat vaginal epithelium submitted to various hormone sequences]. / Ultrastructure de l'épithélium vaginal du rat soumis à différentes séquences hormonales.

Electron microscopical study of estradiol-progesterone interrelationships on vaginal epithelium has been performed on 20 days old rats. Mucification or cornification depends on quantitative sequences of two hormones. Cornification is obtained when estradiol is the latest hormone injected, mucification, when sufficient progesterone.

[Ultrastructure of impuberal vaginas cultivated under various hormonal conditions]. / Ultrastructure de vagins impubères mis en culture dans différentesfèrentes conditions hormonales

Differentiation of rat vaginal epithelium has been studied in organotypic culture in vitro under different hormonal conditions [evolution in association with ovary or testis, and after injection to rats of progesterone 5 mg. and estradiol 0.1 lambda). Whatever the hormonal preconditioning before the vaginal culture the same, complet cornification occurs.

[Ultrastructural study of dysgeneic ovaries of rats, resulting from Misulban administration during fetal life]. / Etude ultrastructurale d'ovaires dysgénésiques de rattes, obtenus par administration de misulban pendant la vie foetale

She-rats have been treated at the 15th day of gestation with Misulban. The she-rats born from the former ones present an ovarian dysgenesis due to a precocious destruction of the germinal cells by the radiomimetic. These dysgeneses are characterized by the presence of cordal epithelial structures and of stroma. Cells whose cytoplasmic infrastructure is characteristic of a steroidogenesis have been searched on ovaries taken of between 15 days and 6 months. In the absence of follicular organization, they appear only from puberty and are localized particularly, between the epithelial structures, in the conjonctive stroma.

[Ultrastructure of testicular Sertoli cells in normal and dysgenesic rats, during the fetal and postnatal periods]. / Ultrastructure de la cellule de Sertoli de testicules de rats normaux et dysgénésiques, en période foetale et postnatale.

Electron microscopic study of Sertoli cells from normal and Misulban-treated rats has been realized during foetal and postnatal life. From 15th day of foetal life, morphological aspects of Sertoli cells plead for a steroidogen activity and protein synthesis. Ultrastructural organels of Sertoli cells are the same in sterile and normal seminiferous tubule, except the Sertoli junctions which are less numerous in sterile tubules and appear later.

Neoplastic surface changes in urothelium of rats after portacaval anastomosis. A combined light and scanning electron microscopic study.

The development of preneoplastic and neoplastic alterations in the urinary tract was investigated by light and scanning electron microscopy in rats after portacaval anastomosis. The changes consisted of slight hyperplasia to papillary hyperplasia after 24 weeks. Carcinomas were present in all animals after 52 weeks. Surface characteristics can be correlated with the sequence of changes in urothelial cells. Short uniform microvilli appear in moderate hyperplasia and a cobblestone formation of the cells is typical of papillary hyperplasia. In transitional cell carcinomas the cells varied in shape and size and they were densely covered with pleomorphic microvilli. Although the cause of tumour induction after portacaval anastomosis is not clearly understood, possible mechanisms are discussed.

Hepatocyte ultrastructure in the rat after long term portacaval anastomosis: a morphometric study.

Hepatocyte ultrastructure was studied in rats after long term portacaval anastomosis (PCS). Compared to controls rats of the same age, in one year PCS rats, the liver atrophy was 24% of the mass. Hepatocytes area was decreased (-16%) but their architecture was grossly normal. The rough endoplasmic reticulum appeared well developed. The morphometric study revealed that: the rough endoplasmic surface density was significantly increased in the two zones of the liver acinus, the smooth endoplasmic reticulum surface density was significantly decreased in zone 1 only and the peroxisomes volume density was increased 2.5 times. These findings differ from data obtained shortly after surgery and probably indicate an adaptation to important functions such as protein synthesis, drug metabolism etc. Increased number of peroxisomes could be possibly linked to the abnormal uric acid metabolism observed in rats with portacaval shunts.

[Ultrastructure of Sertoli cells in male rats treated with "misulban" and stilbestrol]. / Ultrastructure de la cellule de Sertoli chez le rat mâle soumis á l'action du "misulban" et du stilbestrol

The seminiferous tubulars of rats testis, subject to the action of Misulban during their foetal life, contain only Sertoli cells and constitute a good model for their study. From the ultrastructural point of view, these cells present several important mitochondria of tubular crest from, an abundant smooth endoplasmic reticulum, a Golgi apparatus well developed, a cytoplasm rich in ribosomes, Lipids droplets and intercellular junctions whose number increases with age. The administration of diethylstilbestrol, which inhibits gonadotropic and androgenic secretions reduces the signs of activity in the Sertoli cells.

[Ultrastructural study of the different zones of the rat liver acinus after portacaval anastomosis]. / Etude ultrastructurale des différentes zones de l'acinus hépatique de rat après anastomose porto-cave.

Liver atrophy is a main feature in rats with a porto caval shunt. Histological studies revealed small size hepatocytes. Ultrastructural differences between periportal and centrolobular zones were noticed, in particular, the dilatation of the nuclear envelope and of the rough endoplasmic reticulum which appeared dilated, desorganized and sometimes without ribosomes, was more pronounced in the periportal zone. Hepatocytes of this zone might be more sensitive to the decrease of O2 and/or hepatotrophic factors.

Hepatocyte ultrastructure in rats with portacaval shunt. A morphometric study of acinar zones.

The principal reported morphological consequence of portacaval shunt in the rat is liver atrophy. The present study was designed to investigate ultrastructural changes in hepatocytes using electron microscopy morphometry. Two weeks following portacaval shunt, rat livers were fixed by perfusion and hepatocyte organelles from the two opposite zones of the acinus (zones 1 and 3) were quantified. Liver weight/body weight decreased by 50%, hepatocyte-specific volume decreased by 30% (28% in zone 1 nd 35% in zone 3). Estimated sinusoidal space increased, and estimated number of hepatocytes decreased by 50%. Hepatocytes had a normal ultrastructure except for mitochondria. Smooth endoplasmic reticulum-specific surface area was reduced by 65% (zone 3), and rough endoplasmic reticulum surface density was increased in zone 1 only. Mitochondria-specific volume was unchanged but decreased inner and outer membrane-specific surface area in zone 3 suggests in this zone a change in their conformation and possibly their number. Golgi-rich area surface density increased but not significantly. Hepatocyte loss and atrophy and rearrangement of organelles represent a new ultrastructural steady state following portacaval shunt that may help explain the new functional steady state.

Sinusoidal cells in rats with portacaval shunt: a morphometric study.

Sinusoidal cells were studied in rats 2 weeks after portacaval shunt. Livers were perfused with glutaraldehyde via the aorta. Morphometric analysis was performed in periportal and centrolobular zones of the liver acinus. Liver atrophy was the main consequence of portal blood derivation. Per unit of hepatic parenchyma the number of hepatocytes and Kuppfer cells counted on 1 micron section was comparable in portacaval shunt and sham operated rats. 2 weeks after the shunt, sinusoidal cell ultrastructure was nearly normal. Morphometric analysis showed sinusoids slightly enlarged and Kupffer cell volume density increased in both zones. Kupffer cell lysosomal-like structures such as electron-lucent vacuoles and phagolysosomes had larger volume density. Ito cells number and volume density slightly increased after portacaval shunt. These findings suggest that endotoxemia which could occur after portal blood shunting might be better related to shunting than to depression of the reticuloendothelial system.

Failure to induce selective cholestasis in the rat after long-term extrahepatic selective biliary obstruction.

Forty-eight hours after extra-hepatic selective biliary obstruction (SBO), there is evidence of cholestasis in the obstructed lobes (OL). However, some major ultrastructural features of cholestasis are missing. The aim of this work was to investigate the long-term effect of SBO. One month after surgery, and in comparison with sham-operated rats, bile flow, liver weight, and liver weight ratio of obstructed/nonobstructed lobes were normal. Furthermore, there was no evidence of cholestasis in OL by light and electron microscopy. Bile duct communications between obstructed and non-obstructed lobes were evidenced by Indian ink injection. In sham-operated rats, bile duct communications between ducts of the different lobes were involved in bile drainage. It appears, therefore, that the main reason for the lack of cholestasis 1 month after SBO is the drainage of bile from OL through accessory bile ducts.

Hypertrophy of the rat Golgi complex during enhancement of cholesterol and bile acids synthesis.

There are some evidences that the Golgi apparatus could be involved in bile salts transport. In this study we investigate the morphology of the Golgi apparatus in rats with a chronic bile fistula or treated with 4% cholestyramine, a bile salts chelating agent. In both models liver histology was normal by light microscopy. With electron microscopy--compared to sham groups--the only obvious change was the enlargement of the Golgi complex. Morphometric data confirmed that the Golgi rich area volume density was almost doubled after chronic bile fistula or cholestyramine treatment. These data give another support for the participation of the Golgi complex in bile salts transport.