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Biomedical subjects

E Wisse

Publications and source records attributed to E Wisse.

At least 91 records · Page 5Linked to original sources
PubMed1986

Local proliferation and extrahepatic recruitment of liver macrophages (Kupffer cells) in partial-body irradiated rats.

The relative significance of local proliferation and extrahepatic recruitment of Kupffer cells was investigated by partial-body irradiation before the induction of macrophage hyperplasia by zymosan. There was no difference in growth of the Kupffer cells population between nonirradiated rats and rats irradiated with the liver shielded, whereas irradiation of the liver with the rest of the body (bone marrow) shielded resulted in strong inhibition of growth (-61%). Splenectomy combined with bone marrow irradiation inhibited growth to a lesser extent as compared to liver irradiation (-38%). Monocyte and other leukocyte numbers were strongly reduced in peripheral blood and their accumulation in the liver was completely prevented by bone marrow irradiation. Our results demonstrate that local proliferation of resident Kupffer cells represents the predominant source for their increased number during hyperplasia.

Animals↗
PubMed1986

An ultrastructural study of dentinogenesis and amelogenesis in rat molar tooth germs cultured in vitro.

Molar tooth germs from three-day-old rats were cultured successfully for fourteen days, permitting the study of the development in vitro of both extracellular matrix and cellular elements such as odontoblasts and ameloblasts. The ultrastructure of the cultured tooth germs was compared with the ultrastructure of tooth germs in vivo at a comparable developmental stage. Progenitor cells of odontoblasts and ameloblasts were found to differentiate in vitro. Odontoblasts seemed to contain more lysosome-like bodies and fewer secretory granules than in vivo. They formed normally mineralizing dentine or a thick layer of dense, unmineralized predentine with incidentally some amorphous, extracellular material. Enamel was exclusively present opposite well developed dentine. It was often hyper- or hypomineralized and enamel rods were not as regularly shaped as in vivo. In places where no enamel formation had taken place, large amounts of amorphous extracellular material were sometimes seen. From these observations it can be concluded that cellular development in cultured tooth germs appeared more or less normal, but extracellular matrix formation and mineralization were sometimes disturbed.

Ameloblasts↗
PubMed1986

Immunogold localization of procollagen III, fibronectin and heparan sulfate proteoglycan on ultrathin frozen sections of the normal rat liver.

In the present study, we have localized by immunocytochemistry at the LM and EM level, procollagen type III (PIIIP), fibronectin (FN) and heparan sulfate proteoglycan (HSPG). Intracellularly, PIIIP was observed in both parenchymal and endothelial cells. In parenchymal cells, PIIIP was found in Golgi derived vesicles. This observation suggests that PIIIP synthesis is a normal function of liver parenchymal cells. In endothelial cells, vesicles, which could not be identified, were seen to contain PIIIP. This result does not allow to conclude, whether sinusoidal endothelial cells secrete or take up PIIIP. Extracellularly, PIIIP was present around portal and central veins, in the space of Disse and between adjacent parenchymal cells. In the space of Disse, almost all interstitial collagen fibrils reacted with the anti PIIIP antibodies. This observation leads to the conclusion that most fibrils of the space of Disse contain type III in addition to type I collagen molecules. By immunofluorescence, FN was seen mainly along the sinusoids in discrete dots. By EM, FN was found to be present in diffuse material closely associated with the sinusoidal membrane of the parenchymal cells and in strands connecting adjacent parenchymal cells, parenchymal and endothelial cells or parenchymal cells and collagen fibrils. FN was also present in vascular and ductular basal laminae. Strong HSPG reaction was observed around bile ducts. Moderate reaction was seen around blood vessels and in the space of Disse. In the latter location, the ultrastructural distribution of HSPG resembles that of FN, i.e. HSPG is present in diffuse material and in strands.

Animals↗
PubMed1986

Characterization and immunocytochemical localization of dentine phosphoprotein in rat and bovine teeth.

Dentine phosphoprotein (DPP) was isolated from unerupted bovine molars and from rat incisors. The proteins were characterized biochemically and used to immunize rabbits and guinea pigs. Antibody activity was investigated by enzyme-linked immunosorbent assay (ELISA). Guinea-pig anti-rat DPP did not cross-react with bovine DPP, but rabbit anti-bovine DPP did cross-react with rat DPP. Anti-rat DPP antiserum was applied to cryotome sections of rat molar tooth germs and DPP immunoreactivity was seen in dentine, odontoblasts, odontoblast processes and pre-ameloblasts. Anti-bovine DPP antiserum reacted positively in bovine dentine and dentinal tubules. When this antiserum was applied to rat tissue, predentine was positive but dentine was negative. Adsorption experiments with DPP, purified by methods including and excluding precipitation with calcium, suggested that non-calcium precipitable DPP is present in rat predentine. Rat and bovine DPP are thus species-specific and DPP is synthesized by the odontoblasts, transported through their processes and secreted into the dentine.

Amino Acids↗
PubMed1986

Kupffer cells from CCl4-induced fibrotic livers stimulate proliferation of fat-storing cells.

The interaction between fat-storing cells (FSCs) and Kupffer cells (KCs) in vitro has been studied in an attempt to clarify certain aspects of the pathogenesis of fibrotic process in the liver. FSCs and KCs were isolated from the livers of rats either treated with CCl4 for 6 weeks, or with vitamin A for 6 weeks or from untreated rats by the pronase-collagenase digestion method. FSCs were further purified by centrifugation over a double layered metrizamide gradient, and KCs were separated from other sinusoidal cells by the dish adherence technique. FSCs from CCl4-treated rats divided rapidly, while those from vitamin A-treated rats divided slowly, as compared with untreated rats. Furthermore, the proliferation of FSCs was enhanced in the presence of KCs from CCl4-treated rats, but was slightly suppressed by KCs from normal and vitamin A-treated rats. This enhancement was mediated by a non-dialyzable, soluble factor present in the conditioned medium of KCs from CCl4-treated rats, but was not detected in the conditioned medium of KCs from normal or vitamin A-treated rats. From the present study, a growth factor secreted by KCs from CCl4-treated rats may play an important role in controlling the proliferation of FSCs during the pathogenesis of liver fibrosis.

Animals↗
PubMed1986

Cytokinetic analysis of the expanding Kupffer-cell population in rat liver.

Zymosan stimulation in rats provides a useful model for studying the expansion of the Kupffer-cell population in liver, which represents the major population of tissue macrophages. This study, using tritiated-thymidine-labelling experiments, demonstrates that during population expansion at least 90% of the resident macrophages (Kupffer cells) develop proliferative activity. The mean duration of the cell cycle is estimated to be 52 hr, with an S phase of 7 hr. We have calculated that about 75% of population expansion results from local Kupffer-cell replication, whereas the remaining growth results from extrahepatic recruitment of macrophage precursors. These findings conflict with a concept of the mononuclear phagocyte system, which states that resident macrophages are (monocyte-derived) non-dividing end-cells.

Animals↗
PubMed1986

Effect of acetaldehyde on collagen synthesis by fat-storing cells isolated from rats treated with carbon tetrachloride.

In an attempt to elucidate the role of fat-storing cells (FSCs) in alcoholic liver fibrosis, we examined the effects of ethanol and acetaldehyde on collagen synthesis by FSCs isolated from CCl4-treated or normal rats. Isolated FSCs from normal rats showed characteristic lipid droplets in the cytoplasm. FSCs from CCl4-treated rats showed an abundant rough endoplasmic reticulum and a small number of lipid droplets. Collagen synthesis by the cells from CCl4-treated rats was 4-5-fold enhanced as compared with untreated rats. Though ethanol had an inhibitory effect on collagen synthesis by FSCs, acetaldehyde stimulated collagen production by the cells from CCl4-induced hepatic fibrosis, whereas collagen synthesis by the cells from normal rats was not influenced by acetaldehyde. From these results, FSCs are morphologically and functionally changed in liver fibrosis, and the transitional state of FSCs might be important in the pathogenesis of alcoholic liver fibrosis.

Acetaldehyde↗
PubMed1986

Serum and synovial fluid antibodies to collagen in rheumatic diseases: a review.

The literature on the occurrence and significance of antibodies to native or denatured collagen in rheumatic diseases is reviewed. Mainly type I and type II collagen have been investigated, both in serum and synovial fluid, with special reference to their possible role in rheumatoid arthritis. Brief results of the analysis of 40 synovial fluid samples, using an ELISA technique are included.

Arthritis, Rheumatoid↗
PubMed1985

Proliferation, kinetics, and fate of monocytes in rat liver during a zymosan-induced inflammation.

The fate and kinetics of monocytes, recruited to the liver by a single zymosan injection, were investigated by light (LM) and electron (EM) microscopy combined with peroxidase cytochemistry and latex phagocytosis. Ultrastructural and cytochemical differences between these cells and resident Kupffer cells persisted during a 7-day period, demonstrating the existence of two types of hepatic mononuclear phagocytes. Both cell types exhibited a pronounced mitotic activity during their numerical increase. Next to peroxidase-positive (POP) Kupffer cells and monocytes, peroxidase-negative (PON) mononuclear phagocytes were observed. These may represent a monocyte subset and/or possibly Kupffer cell precursors.

Animals↗
PubMed1985

Light and electron microscopic studies of the rat hyalocyte after perfusion fixation.

The characteristic morphology of a not intentionally stimulated hyalocyte is described, using TEM and perfusion fixation. The best results were obtained by retrograde perfusion via the abdominal aorta with a glutaraldehyde- and formaldehyde-containing fixative. The cells, situated in the cortical area of the vitreous body, show mostly an indented nucleus, primary and secondary lysosomes, mitochondria, cisterna, clusters of free ribosomes and a Golgi apparatus. Bristle-coated micropinocytotic vesicles can also be distinguished and in some cells a centriole is visible. Sometimes the cells show many cytoplasmic protuberances. Morphologically the majority of those cells can be considered as resting macrophages.

Animals↗
PubMed1983

Scanning electron microscope observations on the structure of portal veins, sinusoids and central veins in rat liver.

Portal veins can be recognized in SEM by the presence of an accompanying element such as the bile ductule. Endothelial cells within these vessels possess small marginal microvilli. Portal veins show few sinusoidal inlets (direct connections to sinusoids) and no attached "wandering" cells. Sinusoids in periportal areas are narrower and more tortuous than the wider and straighter central ones. Periportal endothelial fenestrae have a larger diameter (111 nm) than central ones (105 nm), but their number per square micron, and therefore the porosity (% open area), is higher in centrolobular sinusoids (7.94 vs 5.96%). Central veins have smoother endothelial cells and show numerous sinusoidal outlets (direct sinusoidal connections). Cells are seen attached to the wall and are probably migrating out of the liver. In the orifices of some sinusoidal outlets, traversing bars can be observed, which obstruct the flow of blood from the sinusoids into the central vein. From our observations and measurements the following conclusions can be drawn: a. In the narrower periportal sinusoids, moving blood cells will be forced against the wall, causing a massage of the space of Disse. This will influence the exchange of fluids and particles through the endothelial fenestrae, and it will cause stirring of the fluid in the space of Disse. b. Centrolobular sinusoids have a larger perimeter and an endothelial lining with a higher degree of porosity. These structural factors will favour transport and uptake processes in the centrolobular parenchyma. c. Sinusoidal blood flow might be expected to be slower in central areas, since the number of sinusoids appear to equal that of the portal region, but their lumen is wider.

Animals↗
PubMed1983

Endotoxin effect on the isolated perfused rat liver: functional and ultrastructural observations.

The effect of E. coli endotoxin on bile flow and hepatic ultrastructure was studied in the isolated perfused rat liver. Within 30 min after its addition to the perfusate, endotoxin caused bile flow reduction. Despite this cholestatic effect, parenchymal cell structure did not show impressive changes on electron microscope examination. This feature contrasts with the in vivo findings by others, and suggests that the activation of extrahepatic mechanisms may contribute to the endotoxin toxicity for parenchymal cells in vivo.

Animals↗
PubMed1981

On the dynamics of HLA-A2 antigen-antibody complexes on the cell membrane of human peripheral blood lymphocytes. A biochemical and electron microscopical autoradiographic study.

This report deals with some dynamic aspects of membrane bound immune complexes of HLA antigens and antibodies. Radiolabelled HLA antibodies were used to sensitize peripheral blood lymphocytes. Upon in vitro incubation of these cells, two different events were detected: 1) Immune complexes and a limited amount of free antibody were shed into the culture supernate; from the immune complexes specific antibodies could be regenerated. 2) Immune complexes were also internalized by means of endocytosis as visualized by electron microscopical autoradiography. Antibodies were found above dense bodies (lysosomes) and above multivesicular bodies. The results are discussed in relation to the biology of membrane bound HLA molecules.

Antigen-Antibody Complex↗
PubMed1978

Filtration effect of endothelial fenestrations on chylomicron transport in neonatal rat liver sinusoids.

The function of endothelial fenestrations in the control of the passage of chylomicrons from the blood to the liver parenchymal cells was studied ultrastructurally in neonatal rats. Measurement of circulating chylomicrons and endothelial fenestrations as well as chylomicrons in the space of Disse at 2--20 h after the onset of suckling revealed a substantial filtration effect of endothelial fenestrations on chylomicrons larger than 250 nm in diameter. Direct uptake of chylomicrons by parenchymal cells was observed to occur by pinocytosis; Kupffer cells endocytosed only very few chylomicrons, and endothelial cells were inactive in this respect.

Animals↗
PubMed1978

Induction of lysosomal storage by suramin.

Isolated livers of rats injected with saline or with suramin (250 mg per kg body weight) 24h previously were perfused with a medium containing radioactively labeled formaldehyde-treated albumin. Suramin-loaded livers released breakdown products at a much lower rate than controls and contained about the double amount of undigested radioactive protein up to about 3 h after the start of the perfusion. These results show that inhibition of proteolysis by suramin as reported previously (Davies et al., 1971; Buys et al., 1973) is not caused by binding of the drug to the substrate in the bloodstream. Electron micrographs of liver sections of suramin-treated rats showed that lysosomes of sinusoidal cells resembled those seen in certain lysosomal storage diseases. The effect of suramin on lysosomal enzymes was studied in vitro. When used at a concentration corresponding to the putative concentration in lysosomes in vivo, the drug inhibited the lysosomal endopeptidases cathepsin Bl and D as well as acid phosphatase. Inhibition of acid phosphatase by suramin in vivo could also be demonstrated by histochemical methods. These results suggest that the observed storage phenomena may be mainly caused by inhibition of lysosomal enzymes.

Albumins↗
PubMed1978

Accumulation and localization of gallium-67 in various types of primary lung carcinoma.

The uptake and location of Ga-67 were investigated in 15 primary pulmonary carcinomas. The accumulation in the tumor was determined by scintigraphy of the patient, grain counts over fields of tumor cells in autoradiographs of tumor-tissue samples, and gamma counts in specimens of the tumor. Good correlation was found between the results obtained with these three methods. The relationship between accumulation of Ga-67 in the tumor and the histologic type of tumor was also studied. Undifferentiated carcinomas, and tumor cells in squamous-cell carcinomas showed significantly more Ga-67 than tumor cells in adenocarcinomas. No correlation was found between the presence of inflammatory infiltrates in or around the tumor and the grade of the scintigraphic images. In the autoradiograms, lymphocytes, plasma cells, granulocytes, and macrophages showed less radioactivity than the tumor cells--or none at all. Collagen fibers appeared to have bound some Ga-67, but necrotic areas showed no uptake.

Aged↗