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Background: Hepatic ischemia-reperfusion (I/R) leads to activation of Kupffer cells (KCs). The activated KCs cause platelet and leukocyte adhesion to the sinusoidal endothelium. Previously, we reported that platelet-endothelium interactions occur earlier than leukocyte responses. The aim of this study was to evaluate the interaction between platelets and KCs in the hepatic microcirculation after I/R., Materials and Methods: Sprague-Dawley rats were divided into three groups: the no-ischemia group (control group; n = 6); the 20-min ischemia group (I/R group; n = 6); and the 20-min ischemia + anti-rat platelet serum group (APS group; n = 6). KCs were labeled using the liposome entrapment method. The number of adherent platelets was observed for up to 120 min after reperfusion by intravital microscopy. To investigate the effects of platelets on I/R injury, rats were injected intravenously with rabbit APS for platelet depletion., Results: In the I/R group, the number of adherent platelets increased significantly after I/R. More than 50% of the adherent platelets adhered to KCs. Electron microscopy indicated that the platelets attached to the KCs after hepatic ischemia. The histologic findings indicated liver damage and apoptosis of hepatocytes in zone 1. In the I/R group, but not in the control and APS groups, serum ALT increased immediately after reperfusion., Conclusions: We succeeded in visualizing the dynamics of both KCs and platelets in the hepatic sinusoids. Liver ischemia induced the adhesion of platelets to KCs in the early period, which could play a key role in reperfusion injury of the liver., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Structural changes in the liver and spleen of albino mice with Astrakhan scrub typhus were studied by electron microscopy. Rickettsia invasion and formation of granulomas induced structural (destructive) and metabolic changes in hepatocytes. Rickettsia were degraded in cytophagosomes and cytolysophagosomes of hepatic macrophages (Kupffer cells) and blood capillary endotheliocytes. In the spleen rickettsia were seen in the extracellular spaces and in various cell populations.

Thalassemia Intermedia (TI) is a clinical definition in use for a spectrum of clinical conditions ranging in severity from the asymptomatic carrier status to the transfusion-dependent status. The histological lesions of the liver in patients affected by TI has not seen well characterized yet. The aim of this study was to define the histological picture of liver disease in TI. To this end we studied our pool of 22 Thalassemia Intermedia patients who underwent liver biopsy; none of them had blood transfusion. We took into consideration fibrosis according to Ishak's staging and iron overload according to Sciot's grading. Moreover, we determined the hepatic iron content by atomic absorption spectroscopy. Our results have shown that, in all patients studied, the histological picture was characterized by the increase in liver iron stores. By Perls's stain haemosiderin appeared to be stored mainly in hepatocytes in the majority of cases. Inspite of the large amounts of liver iron in these patients, fibrosis was absent or mild. We also noted the presence of iron-free-foci, in part of the patients. Our data show that the histological and histochemical picture of liver disease in Thalassemia Intermedia is very similar to that found in Thalassemia Major. The finding of iron-free-foci could induce to consider a follow up of these patients, even if asymptomatic.

We have evaluated the link between haemostatic abnormalities and immune dysfunction in liver disease by evaluating parameters of cellular and humoral immunity in conjunction with coagulation profiles in rats following portacaval anastomosis, induction of portal hypertension by portal vein stenosis or by sham surgical procedures. Twelve weeks following surgery, portacaval shunted rats were markedly anaemic (8.9 +/- 0.6 g/dl; controls 12.3 +/- 1.4 g/dl, p < 0.05), had low plasma fibrinogen levels (0.6 +/- 0.3 g/l, controls 2.5 +/- 0.2 g/l p < 0.05) and markedly elevated fibrin(ogen) degradation products (FDP) titres (1/40-1/80; controls < 1/10. p < 0.05). Portal vein stenosed rats were less anaemic (11.5 +/- 0.8 g/dl), had near normal fibrinogen levels (2.1 +/- 0.3 g/l) but elevated FDP levels (1/40-1/80). Both portacaval shunted and portal vein stenosed rats had elevated serum IgG levels (35.1 +/- 14.1 g/l; 29.2 +/- 13.9 g/l respectively; control values 20 +/- 5.9 g/l p < 0.05 for comparison with both experimental groups). Intrinsic lymphocyte proliferation to T and B cell mitogens was markedly depressed in the portacaval anastamosed rats when compared to controls. Serum factors inhibitory to control lymphocyte proliferation were noted in the shunted rats. Phagocytosis of complement and immunoglobulin sensitised sheep RBC by Kupffer cells purified from rats that had undergone portacaval shunting was markedly reduced (p < 0.05). The increased degree of phagocytosis following exposure to LPS-endotoxin (50 micrograms/ml) was proportionate in degree to the control group. Spontaneous release of bioactive lymphocyte activating factors (IL-1 and IL-6) by purified rat sinusoidal cell populations was decreased in the portacaval shunted group, and decreased still further following stimulation with LPS (50 micrograms/ml) in vitro. The observation that many of the haemostatic and immunological abnormalities associated with chronic liver disease are present in rats with surgically created portacaval shunts or with induced portal hypertension, lends credence to the hypothesis that shunting of portal blood is, at least in part, responsible for many of the systemic manifestations associated with chronic liver disease.

Results obtained during experiments on rats intoxicated with Gramoxone herbicide containing 25 per cent paraquat are reported using light- and electron microscopic examinations. The development of the liver's lesion may be divided into three phases: in the first phase predominates the destruction of the cytoplasmic organella in the hepatocytes, in the second one the proliferation of the Kupffer cells and in the third one the lesion of the biliary region. The regeneration is slower than in case of a healthy liver: the hepatic parenchyma is recovering at first and only later the epithelium of the bile ducts. The mechanism of action of the paraquat intoxication is discussed.

The cytoplasm of hepatocytes in a liver biopsy from a patient with acquired immunodeficiency syndrome (AIDS) treated with sulfamethazole-trimethoprim contained concentric membranous bodies (CMB) and giant mitochondria. By light microscopy the general architecture of the liver was unaltered. By electron microscopy one to three CMB were present in random distribution within several cells in equal periportal and centrilobular localization. CMB were irregularly rounded or ovoid, loosely ribosome-studded lamellar whorls. Some were agranular or in parallel arrangement. Giant mitochondria often with paracrystalline inclusions were frequently in close association with CMB. Tubuloreticular inclusions were noted in Kupffer cell cytoplasm. Since CMB have been infrequently observed in human hepatocytes, are rare in nonneoplastic human liver, and have not been previously reported in association with AIDS, their appearance may relate to regenerative changes and/or sulfamethazole-trimethoprim therapy.

Recent studies have demonstrated that aged rats are more susceptible to the lethal effects of endotoxin (ET) than young rats. The early (15 min to 7 h) hepatic ultrastructural and biochemical changes induced by ET in young (6 months) and aged (24 months) rats were evaluated to elucidate cell populations and/or the mechanisms that may be responsible for the previously observed differential effects. Aged rats given ET had significantly increased numbers of neutrophils in hepatic sinusoids at 30 min and thereafter as compared with ET-treated young rats. Morphologic evidence of coagulation within hepatic sinusoids, including aggregates of fibrin enmeshed among polymorphonuclear leukocytes and platelet aggregates, was frequently observed in ET-treated aged rats but not in ET-treated young rats. In contrast, Kupffer cells of ET-treated young rats frequently contained phagocytized neutrophils and platelets, whereas this phenomenon was rarely observed in Kupffer cells of ET-treated aged rats. Hepatocellular morphologic injury was more pronounced and occurred at earlier time periods in ET-treated aged rats, and was accompanied by significant increase in hepatic transaminases. ET-treated aged rats had an earlier onset and greater severity of endothelial cell injury than did ET-treated young rats. The results of this study indicate a greater aggregation of blood elements in the hepatic sinusoids of aged rats following the intravenous administration of ET, which suggests that a greater diminution in microcirculation was induced in aged rats by ET. Additionally, the increased phagocytosis of inflammatory cells by Kupffer cells of young rats may be a mechanism which affords protection against endotoxin-induced lethality.

To investigate the possibility of HIV1 infection of liver cells, liver samples from 17 infected patients were studied. A monoclonal antibody directed against the p24 gag HIV1 protein was used in an immunoperoxidase assay and yielded positive results in 7/17 samples. Staining by anti-p24 antibody was of three types: diffuse in Kupffer cells of most samples, inside granuloma and in some sinusoidal cells the origin of which was difficult to ascertain. In 5 further liver specimens, HIV1 RNA were identified by in situ hybridization in inflammatory mononuclear cells and/or in scattered sinusoidal cells. Attempts to locate the CD4 membrane antigen showed that it was mainly present on endothelial sinusoidal cells. These results indicate that liver cells, including Kupffer cells, might be infected by HIV1.

A light and electron microscopic investigation of liver tissue from three homozygous (Pi-type ZZ) and three heterozygous (Pi-type MZ) alpha 1-antitrypsin deficiency patients is presented. All had slightly elevated levels of serum amino transferases as the only signs of liver damage. Light microscopical investigation showed minor periportal fibrosis and periodic acid-Schiff-positive globules in the homozygous patients, but no specific findings besides fatty changes were seen in the heterozygous patients. Electron microscopical investigation was performed on periportal and centrilobular areas separately. In the three homozygous patients, dilatation of endoplasmic reticulum was found in many periportal liver parenchymal cells. In these cells, a marked increase in peroxisomes was also noted and in some instances they showed signs of cell necrosis. Evidence of Kupffer cell heterophagy of such cells was also found, thus indicating that they had died. Only in one liver parenchymal cell from one of the three heterozygous patients was evidence of a dilated endoplasmic reticulum found. No increase in peroxisomes was found and no apparent signs of liver cell necrosis were noted. An increased amount of lipofuscin-like material in the lysosomes was encountered in liver cells both from patients with homozygous and heterozygous alpha 1-antitrypsin deficiency. Based on these findings, it is suggested that cell death occurs in cells with a dilatation of the endoplasmic reticulum. If these findings are important for the pathogenesis in liver disease in alpha 1-antitrypsin deficiency, the present study suggests that the risk to develop liver disease is less in heterozygous patients since, with one exception, alterations of the same nature were not found in their hepatocytes.

The hepatic granulomas in experimental cryptococcosis were analyzed by peroxidase (PO) cytochemistry. Cryptococcus neoformans was inoculated intravenously into rats (group A), and some rats were administrated with dextran sulphate to suppress Kupffer cell functions before inoculation (group B). All rats were sacrificed 7 days after inoculation. The livers were examined PO cytochemically. In addition, the liver, spleen, lungs, kidneys and brain were also examined histopathologically. The hepatic granulomas consisted of the following four type cells; exudate macrophages (type I), PO-negative macrophages (type II), Kupffer cells (type III), and other inflammatory cells (type IV) such as neutrophils and lymphocytes. The percentages of the granuloma-composing cells in group A were 10.3% (type I), 27.3% (type II), 52.9% (type III) and 9.5% (type IV), respectively. In contrast in group B, type II cells outnumbered type III cells by a ratio of 5:3. In group B, necrosis and hemorrhage were observed in the granuloma. The lesions in the lungs changed from granulomatous to cystic ones after suppression of the Kupffer cell functions. These results suggest that resident macrophages such as Kupffer cells may play an important role in the formation of cryptococcal lesions.

Kupffer cells were observed in liver biopsy tissues of 9 cases of liver diseases by scanning electron microscopy to prove Kupffer cell proliferation numerically. Kupffer cell count per 0.01 mm2 of cracked surface of liver lobule was 1.2 +/- 0.3 in the convalescent stage of a mild acute hepatitis case and 1.2 +/- 0.1 in a chronic persistent hepatitis case with slight inflammation. Whereas it was increased to 2.4-5.5 (P less than 0.01) in the convalescent stage of moderate to severe acute hepatitis cases, 1.8 +/- 0.1 (p less than 0.05) in a chronic active hepatitis case, 2.5 +/- 0.3 (p less than 0.001) in an alcoholic portal fibrosis case and 2.2 +/- 0.4 (p less than 0.001) in a liver cirrhosis case. Kupffer cell count per mm3 of liver lobule was estimated roughly 3,500 in the convalescent stage of a mild acute hepatitis case and in a mild chronic persistent hepatitis case and 7,000 to 16,000 in the convalescent stage of moderate to severe acute hepatitis cases.

Two sisters had erythropoietic protoporphyria and a spectrum of liver disease. One (F.B.) died in hepatic failure within 3 months after the development of jaundice. Only 10 months before she died, she had exhibited only bromsulfalein retention and a borderline increase in serum transaminase. Surgical exploration because of the jaundice revealed patency of the bile ducts which was confirmed at autopsy. Wedge biopsy and autopsy specimens of liver showed an active cirrhosis with massive amounts of protoporphyrin in Kupffer cells, portal histiocytes, bile canaliculi and parenchymal cytoplasm. The other sister (L.R.) had never had symptomatic liver disease and only a slight increase in serum transaminase and bromsulfalein retention. On needle biopsy, the liver specimen showed portal inflammation with erosion of limiting plates, occasional bridging between triads and central areas of cell dropout. Protoporphyrin pigment was present in portal histiocytes, areas of central collapse and, more rarely, in parenchymal cytoplasm. These studies demonstrate that significant, progressive hepatic disease may occur insidiously in erythropoietic protoporphyria, and that once jaundice appears it may be followed rapidly by fatal hepatic failure.

The fate of Kupffer cells in mice for 3 days following injection with polystyrene latex particles (0.2 and 2.0 micron in diameter) was studied by electron microscopy. Kupffer cells took up the latex particles by pinocytosis as well as by phagocytosis. The particles ingested were in contact or fused with lysosomes in the cell. Two days after the final injection, most Kupffer cells were already stuffed with the particles. Within one month, cell clumps or cell aggregates, which could be called granuloma, were formed in the liver connective tissue space, i.e., Disse spaces, interlobular connective tissue spaces and subperitoneal connective tissue spaces. They were mostly composed of cells laden with numerous latex particles. The large granulomas were 80-120 micron in diameter. In each granuloma, endogenous peroxidase was localized in the cisternae of the nuclear envelope and of the rough endoplasmic reticulum of most cells, and in the cytoplasmic granules of some other cells. The former is known to be a Kupffer cell, and the latter, a monocyte. The granuloma further contained a few intermediate cells, showing peroxidase activity in the cisternae of the nuclear envelope and of the rough endoplasmic reticulum, and also in the cytoplasmic granules, phagocytic cells without peroxidase activity, granulocytes, and plasma cells. Hepatic sinusoidal endothelial cells, attenuated in shape, also took up latex particles of a 0.2 micron diameter and rarely with a 2.0 micron diameter in their cytoplasm. Some Kupffer cells in the granuloma filled with numerous latex particles were labeled with 3H-thymidine (2.5 mCi in total dose) after subcutaneous injection ten times for 80 hr. In the animals 8 months after the injection of the latex particles, numerous large granulomas were distributed throughout the liver in the interlobular or subperitoneal connective tissue space. The formation of the granuloma of Kupffer cells is considered to play a great role in the disposing of foreign materials from the functional liver parenchymatous tissue.

A simple, intuitive procedure for the stepwise classification of objects in n-dimensional feature spaces is presented. Each classification step is based on a single feature decision and provides an optimal separation of the objects of only one class from the objects of all other classes. The algorithm of this procedure is implemented on a minicomputer of an image-analysis system. Testing of the classifiers on biomedical data (213 slides of diseased and normal liver tissue) yielded good results requiring few decisions and threshold parameters: 152 correct classifications, 16 incorrect classifications and 45 rejections.