Ultrastructural characteristics of hyperplastic alterations in the liver of congenital portacaval-shunt rats.

A congenital portacaval shunt was discovered in five rats. In these animals the hepatic artery was the only blood vessel perfusing the liver; the portal vein was absent. The livers were small and mainly hypoplastic, but light microscopy revealed the occurrence of focal hyperplastic alterations and occasional hyperplastic nodules. TEM and SEM showed these areas to be composed of clustered hepatocytes, separated by widened intercellular spaces. The cell membranes carried numerous pleomorphic microvilli, and the cytoplasma contained densely packed mitochondria, some of which were giant sized. Liver cells in the centrilobular region were hypoplastic. Comparison with findings of experimental portacaval anastomosis suggest that in congenital-shunt animals, the overall hypoplasia of the liver with the formation of hyperplastic areas is a consequence of the lack of portal blood.     

Ultrastructural alterations in cardiac muscle of diabetic BB Wistar rats

Summary The cardiac muscle of BB Wistar rats suffering from diabetes for 8 and 16 weeks (8-Wk and 16-Wk of DM) were examined by light and electron microscopy. The diabetic rats were kept alive by injections of small doses of insulin and exhibited severe hyperglycaemia, glycosuria and weight loss. The heart/body weight ratio of all diabetic groups was greater than that of age matched controls. Over the experimental period, the left ventricular myocardium of the diabetic BB rats sustained damage that was progressively more serious with the duration of the diabetic state. In BB rats after 8-wk of diabetes the myocardium contained large numbers of lipid droplets and glycogen granules around mitochondria which showed patchy swelling, and slight loss of myofilaments. Disruption of mitochondrial membranes and extensive loss of myofilaments were seen in rats diabetic for 16 wk. In addition, dilatation of the sarcoplasmic reticulum-transverse tubular system, formation of a contraction band and myelin bodies and widening of the intercellular space at the fasciae adherens of the intercalated disc were characteristically observed in BB rats after 16-wk of diabetes. However, there were no evident alterations in the capillaries of any diabetic BB rats. Morphometric analyses showed the volume percentage of myofibrils in diabetic rats to be significantly decreased when compared with controls. The loss of myofibrillar elements may be a primary damage induced by insulin deficiency. The formation of contraction bands suggests Ca²⁺ overload caused by diabetic metabolic disturbances.     

Ultrastructural cytochemistry of eosinophilic inclusions in the cells of hyperplastic nodules and hepatomas in mouse liver.

Intracisternal inclusions in the cells of 48 hyperplastic nodules and hepatomas in mouse liver were examined by electron microscopy to determine the precise compositions of the inclusions in relation to their ultrastructure, and some preliminary attempts at isolation and chemical analysis of the inclusions were performed. We classified the inclusions into two types. One was mainly of larger size, consisting of a single electron-lucent core and a granular cortical zone of high electron density. The other type was smaller, with a number of tiny, electron-lucent areas crowded into the central area instead of a single core. The cortical material of the inclusions was digested by pepsin treatment of thin sections, whereas the core and the electron-lucent areas within the cortical zone were not extracted. On the other hand, in materials treated with ethanol before post-osmication, only the core and electron-lucent areas within the cortical zone were partially extracted. The ultrastructure of the isolated inclusions was very similar to that of inclusions in situ. The chemical composition of the isolated fractions was estimated to be 60% protein and 35% lipid. Electrophoretically, the protein of this fraction showed a single band. We conclude that the cortical substance is proteinaceous in nature, probably consisting of a single protein or a group of proteins with identical electrophoretic mobility, whereas the core is composed of lipid. The possibility that the inclusions are due to an impairment in the mechanism of intracellular lipoprotein transport is discussed.     

Ultrastructural detection of cholesterol in the liver of alcoholic rats

Central Research Institute of Gastroenterology, Moscow. Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 109, No. 5, pp. 510–512, May, 1990.     

抑郁模型大鼠胃窦部变态反应及超微结构改变

目的：观察抑郁模型大鼠胃窦部变态反应及超微结构改变。方法:将慢性、不可预见性、非同质性应激原作为抑郁模型,通过免疫荧光组织化学及超微结构形态学观察抑郁模型组(n=10)和正常对照组 (n=10)大鼠胃窦部的免疫变态反应及形态学的变化。结果:抑郁模型组大鼠胃窦黏膜组织肥大细胞胰蛋白酶1（MCP-1）平均免疫荧光强度值(37.4±7.7), 显著高于对照组（24.8±5.6）,P＜0.05。抑郁模型大鼠胃窦黏膜组织肥大细胞激活、增殖及颗粒增生。超微电镜观察发现,抑郁模型组大鼠胃窦黏膜组织肥大细胞表现为：肥大细胞向血管、神经和单核细胞周围渗透,肥大细胞膜折皱,细胞内含有非同质的、非均匀、低电子密度颗粒,部分颗粒到达膜表面、成为丝状物、空颗粒及脂质体,细胞核呈梭形;肥大细胞周围白细胞、单核细胞、巨噬细胞渗出;肥大细胞激活脱颗粒,脱落的颗粒趋化到巨噬细胞表面;白细胞颗粒与肥大细胞膜黏附形成桥接;巨噬细胞吞噬肥大细胞激活脱落的颗粒。结论:抑郁模型大鼠胃窦部发生免疫变态反应,肥大细胞对微环境的变化一方面表现肥大细胞细胞数显著增加,另一方面表现为其表型的变化。     

Ultrastructural hepatic alterations in hamsters and jirds after experimental infection with the liver flukeOpisthorchis viverrini

Changes in the hepatocytes of male hamsters (Mesocricetus auratus) and jirds (Meriones unguiculatus) at 220 days after experimental infection with the liver flukeOpisthorchis viverrini were studied by light and electron microscopy. The hepatocytes of the control group were characterized by an intracellular compartmentation. A globular nucleus was located centrally. The main features of the perinuclear zone were the cisternae of the rough endoplasmic reticulum (RER) and interjacent mitochondria, lysosomes, and peroxisomes. The peripheral cell region was dominated by glycogen fields and scattered lipid droplets, which were surrounded by anastomosing tubules of the smooth endoplasmic reticulum (SER). An immense proliferation of the SER was striking in the hepatocytes of animals infected withO. viverrini. Coincidentally, the intracellular compartmentation disappeared. Glycogen rosettes, RER, lysosomes, and lipid droplets were distributed irregularly all over the cell, the latter being observed more frequently than in control animals. The nuclei showed lobe-like protrusions and were enlarged. The mitochondria were often dumbbell-shaped and showed pathologic degenerations up to lysis. Our results resemble those of numerous investigations concerning hepatocellular alterations caused byN-nitroso compounds. Therefore, these observations suggest a synergistic effect for trematode infection andN-nitroso compounds in the pathogenesis of opisthorchiasis. The cellular alterations observed in the hepatocytes ofOpisthorchis-infected animals together with the accumulation of intermediate filaments seen in the adjacent bile-duct epithelia and in the epithelium of the gallbladder seem to indicate a disturbance of the cell metabolism and might be related to a neoplastic transformation.Abbreviations used in the figures bd bile duct - be bile-duct epithelium - c bile canaliculus - fl fluke - gd Golgi apparatus - gl glycogen - gr granulocyte - H hepatocyte - if intermediate filaments - li lipid droplet - lys lysosome - m mitochondrion - mv microvilli - mvb multivesicular body - n nucleus - nu nucleolus - pc periductual connective tissue - RER rough endoplasmic reticulum - SER smooth endoplasmic reticulum - sg secretory granules - si sinusoid - v vacuole     

大鼠脑脊髓不同部位室管膜上皮的超微结构特征

目的：研究大鼠脑和脊髓不同部位室管膜上皮超微结构的区域性差异,并探讨其相应的功能。方法：应用透射电子显微镜法。结果：室管膜上皮衬于脑室、中脑水管和脊髓中央管的内表面,不同部位可见单层扁平、立方或假复层柱状各型上皮。细胞游离缘均具有纤毛、微绒毛及分泌泡,但其形态数量因部位而不同。结论：室管膜是脑脊髓腔面具有复杂功能的一层衬里,在脑脊液的跨越质膜转运及参与驱动脑脊液循环过程中具有重要作用。     

Ultrastructural alterations in hexafluoroacetone-induced testicular atrophy in the rat

Testicular atrophy was induced in rats by dermal application of hexafluoroacetone (HFA) at 39 or 130 mg/kg/day for 14 days, but not at a dosage of 13 mg/kg/day. Affected germ cells were mostly spermatids and to a much lesser extent spermatocytes; spermatogonia were unaffected. Late spermatids were retained in Sertoli cells and showed degenerative changes. Sertoli cells exhibited cytoplasmic vacuolation, distended endoplasmic reticulum, and a marked increase in lipid droplets. Leydig cells exhibited a slight increase in lipid droplets, fewer mitochondria, and diminution and segregation of the agranular endoplasmic reticulum from mitochondria. A correlation between ultrastructural and biochemical changes in HFA-induced testicular atrophy is presented.     

Ultrastructural changes in hepatocytes during the development of experimental cirrhosis of the liver in rats

During the development of toxic cirrhosis of the liver, necrosis and fibrosis are accompanied by intracellular reparative regeneration of the damaged cells and compensatory hypertrophy of the intact cells, aimed at maintaining the specific function of the liver. It is postulated that the outcome of cirrhosis is determined by whichever is the predominant processdeath, regeneration, or hypertorphy of the cells, and its progression is connected with overstrain and increasing exhaustion of the intracellular compensatory-adaptive mechanisms.     

Ultrastructural alterations in livers with metastasis.

The electron microscopic examination of 13 biopsy specimens of livers that contained metastatic carcinoma revealed degenerative alterations of the mitochondria, cystic dilatation of the endoplasmic reticulum, increased amounts of osmiophilic material, some in various stages of autophagocytosis, and lipid vacuoles within the hepatocytes. In ten of 13 cases, the hepatocytes demonstrated mitochondrial paracrystalline inclusions. The observation of the latter structures in edematous hepatocytes containing phospholipid-rich osmiophilic deposits tends to confirm the experimental hypothesis that paracrystalline inclusions are caused by the precipitation of unmasked phospholipids. The spectrum of ultrastructural findings suggests hypoxia and impaired lipid metabolism of the hepatic tissue as a result of congestion and bile stasis caused by the tumor nodules.     

Ultrastructural appearances of preneoplastic liver nodules induced through sequential treatment in rats

The ultrastructural appearances of preneoplastic liver nodules induced in male Wistar rats through sequential treatment with diethylnitrosamine (DENA) and 2-acetylaminofluorene (2-AAF) followed by partial hepatectomy were investigated. Although separately non-specific, the lesions reported represented altogether a fairly characteristic pattern consistent with previous observations in tumors and in preneoplastic nodules induced by long-term treatment with single carcinogens. Such data support the view that sequential treatment followed by partial hepatectomy is a reliable method to study early phenotypic changes in hepatocarcinogenesis. Such treatment is also advisable because it requires only a short period of latency in comparison to other in vivo screening tests of potential carcinogens.