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Biomedical subjects

L Biempica

Publications and source records attributed to L Biempica.

At least 37 records · Page 2Linked to original sources
PubMed1983

Rat liver canalicular membrane vesicles. Isolation and topological characterization.

Canalicular plasma membranes were isolated from rat liver homogenates using nitrogen cavitation and calcium precipitation methods. Compared with homogenates, the membranes were enriched 55- to 56-fold in gamma-glutamyltransferase, aminopeptidase M, and alkaline phosphatase activities and showed very low enrichment in markers of other membranes. By electron microscopy, the membrane preparation contained neither junctional complexes nor contaminating organelles and consisted exclusively of vesicles. The presence of vesicles was also evident from the osmotic sensitivity of D-[6-3H]glucose uptake into the membrane preparation. Antisera obtained from rabbits immunized with highly purified rat kidney gamma-glutamyltransferase inhibited the transferase activity of intact or Triton X-100-solubilized membranes by 45-55%. Treatment of vesicles with anti-gamma-glutamyltransferase antisera and anti-rabbit IgG antisera increased the apparent density of the membranes during sucrose density gradient centrifugation. gamma-Glutamyltransferase and aminopeptidase M activities were selectively removed from the vesicles by limited proteolysis with papain without changing the intravesicular space or alkaline phosphatase activity of the membranes. Specific binding of anti-gamma-glutamyltransferase antibody to the outer surface of isolated hepatocytes was observed as measured by the antisera and 125I-labeled protein A; binding followed saturation kinetics with respect to antibody concentration. These data indicate that the isolated canalicular membrane vesicles are exclusively oriented right-side-out and that gamma-glutamyltransferase and aminopeptidase M are located on the luminal side of rat liver canalicular plasma membranes.

Animals↗
PubMed1983

Regulation of growth and differentiation of a rat hepatoma cell line by the synergistic interactions of hormones and collagenous substrata.

Serum-free, hormonally defined media have been developed for optimal growth of a rat hepatoma cell line. The cells' hormonal requirements for growth are dramatically altered both qualitatively and quantitatively by whether they were plated onto tissue culture plastic or collagenous substrata. On collagenous substrata, the cells required insulin, glucagon, growth hormone, prolactin, and linoleic acid (bound to BSA), and zinc, copper, and selenium. For growth on tissue culture plastic, the cells required the above factors at higher concentrations plus several additional factors: transferrin, hydrocortisone, and triiodothyronine. To ascertain the relative influence of hormones versus substratum on the growth and differentiation of rat hepatoma cells, various parameters of growth and of liver-specific and housekeeping functions were compared in cells grown in serum-free, hormonally supplemented, or serum-supplemented medium and on either tissue culture plastic or type I collagen gels. The substratum was found to be the primary determinant of attachment and survival of the cells. Even in serum-free media, the cells showed attachment and survival efficiencies of 40-50% at low seeding densities and even higher efficiencies at high seeding densities when the cells were plated onto collagenous substrata. However, optimal attachment and survival efficiencies of the cells on collagenous substrata still required either serum or hormonal supplements. On tissue culture plastic, there was no survival of the cells at any seeding density without either serum or hormonal supplements added to the medium. A defined medium designed for cells plated on tissue culture plastic, containing increased levels of hormones plus additional factors over those in the defined medium designed for cells on collagenous substrata, was found to permit attachment and survival of the cells plated into serum-free medium and onto tissue culture plastic. Growth of the cells was influenced by both substrata and hormones. When plated onto collagen gel substrata as compared with tissue culture plastic, the cells required fewer hormones and growth factors in the serum-free, hormone-supplemented media to achieve optimal growth rates. Growth rates of the cells at low and high seeding densities were equivalent in the hormonally and serum-supplemented media as long as comparisons were made on the same substratum and the hormonally supplemented medium used was the one designed for that substratum. For a given medium, either serum or hormonally supplemented, the saturation densities were highest for tissue culture plastic as compared with collagen gels.(ABSTRACT TRUNCATED AT 400 WORDS)

Actins↗
PubMed1983

Immunohistochemical localization of collagenase in hepatic murine schistosomiasis.

It has been previously demonstrated that collagenase activity and collagen synthesis in hepatic granulomas of mice infected with S. mansoni cercariae are maximal 8 weeks after infection; however, total liver collagen content continues to increase. Now the anatomic relationships among collagenase and collagen, granulomas, and hepatic parenchyma in normal mice and in mice infected with S. mansoni are studied. Trypsin-activated collagenase was purified from the media of cultured granuloma explants and anti-collagenase immunoglobulin G was purified from immunized rabbits. The IgG cross-reacted with liver granulomas and active and inactive forms of collagenase, but did not react by immunodiffusion in agar with other neutral proteases or homogenates of schistosome eggs or normal liver. Cryostat sections of liver from normal and infected mice were studied by indirect immunohistochemical methods using fluorescein, rhodamine, and peroxidase labels. Collagenase localization was restricted to areas of collagen deposits in granulomas and hepatic parenchyma. Ultrastructural studies revealed collagenase on the surface of collagen fibers. Hepatocytes of normal mice showed delicate staining at the sinusoidal surface. At all times, immunoreactive collagenase was intimately associated with its substrate, where it presumably initiated collagen degradation. This localization provides a rationale for possible therapeutic approaches to control fibrogenesis through collagenase induction or activation.

Animals↗
PubMed1983

Liver collagen-type characterization in human schistosomiasis. A histological, ultrastructural, and immunocytochemical correlation.

Liver biopsies of four patients with hepatosplenic schistosomiasis, two patients with schistosomiasis and chronic active hepatitis, two patients with chronic active hepatitis and four control patients with no clinical evidence of either disease, were examined by standard light microscopic techniques, electron microscopy and immunocytochemical staining for collagen type I, III and B. Pure schistosomiasis showed the classical "clay-pipe stem fibrosis" and granulomata composed of eosinophils, macrophages and lymphocytes. In that group, the hepatocellular damage was less conspicuous than in the groups with chronic hepatitis and was usually confined to the granulomatous or fibrotic areas. Destruction of the normal architecture and infiltration by macrophages and lymphocytes with severe damage of hepatocytes was found only in the cases of chronic active hepatitis, with or without associated schistosomiasis. Increased collagen deposits were demonstrated in all three groups. Types I, III and B were found in the enlarged portal triads and fibrotic septa. The intranodular or intralobular collagen stained negatively for type I and strongly positive for types III and B.

Collagen↗
PubMed1982

Enflurane hepatitis.

Enflurane (ethrane; 2-chloro-1,2,2-trifluoroethyl difluoromethyl ether) has been widely used as an alternative general anesthetic agent to halothane over the past decade because halothane has been directly linked to hepatocellular damage. Several case reports have subsequently described a hepatitis after exposure to enflurane. We describe another case of enflurane hepatitis which supports earlier reports of this entity, discuss possible mechanisms of such hepatocellular damage, and review the pertinent literature.

Anesthesia, General↗
PubMed1981

Small-intestine involvement in Waldenstrom's macroglobulinemia. Case report and review of the literature.

A patient presented with a three-year history of diarrhea and was found to have a monoclonal gammopathy (IgM lambda) and a malabsorption syndrome with dilatation of the small bowel. Small-intestinal biopsy revealed a homogeneous eosinophilic granular material between the epithelial cells. On electron microscopy this material was shown to consist of an electron-opaque background mixed wit radiolucent lipid sheres. Immunofluorescent studies showed the accellular material to consist entirely of IgM-reactive material. The patient's course and a review of the literature is presented.

Biopsy↗
PubMed1980

Immunocytochemical localization of type B collagen: a component of basement membrane in human liver.

An indirect immunofluorescent method for localizing specific types of collagen was applied to unfixed cryostat sections of autopsy and biopsy specimens of normal and fibrotic human livers. Monospecific antibodies to Types I, III, and B collagens were raised in goats by injecting collagens extracted from normal and fibrotic human livers. The antibody against B collagen stained the delicate sinusoidal meshwork within the lobule that closely paralleled in distribution the staining of reticulin fibers as seen in classical silver preparations. Antibody to Type III collagen stained at the sinusoidal aspect of the hepatocytes in a pattern similar to anti-B antibody. All three antibodies tested strongly stained the portal tracts and the fibrotic bands in specimens with cirrhosis. These observations indicate that reticulin fibers within the liver lobule contain both Type III and Type B collagen.

Antibodies↗
PubMed1980

Cronkhite-Canada syndrome: report of a case with bacteriologic, immunologic, and electron microscopic studies.

A case of Cronkhite-Canada syndrome is presented. The patient developed protein-losing enteropathy, generalized gastrointestional polyposis, skin pigmentation, onychodystrophy, and alopecia. This patient also exhibited certain unusual features such as: fluctuating dermal manifestations, sclerodermalike skin changes, elevated levels of carcinoembryonic antigen, retinal detachment, cataracts, and cerebellar atrophy. Bacteriologic studies of small intestinal fluid, chromosomal analysis, immunologic investigations, and morphologic studies failed to provide any etiologic clues.

Adult↗
PubMed1979

Liver collagen synthesis in schistosomiasis mansoni.

We determined collagen synthetic rates and utilization of key amino acid precursors of collagen in slices of wedge liver biopsy specimens obtained at required surgery from 9 patients with hepatosplenic schistosomiasis and from 4 control patients. The liver specimens from the patients with schistosomiasis showed advanced fibrosis, with histologic evidence of schistosomiasis alone in four, and both schistosomiasis and chronic active hepatitis in five cases. Liver slices were incubated with radioactive proline, arginine and glutamine, using quantitative assay conditions validated earlier for murine schistosomiasis. Collagen peptide synthesis in slices from all nine fibrotic liver specimens was 4- to 25-fold greater than normal and correlated positively with liver collagen content, which was 2- to 5-fold greater than normal. Free proline, an amino acid that may contribute to regulation of collagen peptide synthesis, was increased in six of the nine fibrotic liver specimens, and proline was actively formed from arginine in liver slices from all specimens. These measurements of the initial steps of collagen biosynthesis in fibrotic human liver are quantitatively similar to those previously made of the same processes in experimental animals.

Adolescent↗
PubMed1978

Coronary intimal sclerosis in Morquio's syndrome.

Mitral valve, coronary arteries, cartilage, and liver were studied by light and electron microscopy in a 15 year old boy with Morquio's syndrome, a genetic mucopolysaccharidosis, in which a deficiency of lysosomal hexosamine sulfatase is associated with accumulations of keratan sulfate in various organs. Coronary artery intimal sclerosis was a prominent feature of this disorder. Ultrastructural examination revealed numerous intimal smooth muscle cells containing storage vacuoles consistent with lysosomes. This was associated with marked interstitial deposition of collagen, elastin, and basement membrane material. Recent studies of human and experimental atherosclerosis have demonstrated the accumulation of cholesterol within vascular smooth muscle cell lysosomes. Intralysosomal accumulation of substrates other than cholesterol is also associated with vascular intimal sclerosis in genetic lysosomal disorders such as Fabry's disease and Hurler's syndrome. Lysosomal storage of undegraded substrate may be an important pathogenetic mechanism in the development of sclerotic vascular lesions.

Adolescent↗
PubMed1978

The histiocytic origin of the multinucleated giant cells in myeloma kidney.

A recent case of myeloma kidney disease was studied to determine the cellular origin of the syncytial multinucleated giant cell. Light, immunofluorescence, and electron microscopy of the giant cells revealed features characteristic of histiocytes. This finding contradicts the generally accepted conclusion that the giant cell represents a syncytial mass of degenerating or reactive tubular epithelial cells. We conclude that the giant cells arise in the interstitial tissues, migrate through breaks in the tubular basement membrane, and engulf and surround intratubular protein casts.

Aged↗
PubMed1977

Carcinoma of the breast with multinucleated reactive stromal giant cells. A light and electron microscopic study of two cases.

Two unusual carcinomas of the breast are described, containing nests of infiltrating neoplasm situated within stromal lacunar spaces, and surrounded by numerous benign appearing multinucleated giant cells. Within the stroma, there was extensive hemorrhage, hemosiderin pigment deposition, and large numbers of mononucleated inflammatory cells. The morphology of both tumors resembled the giant cell tumor of bone. Although a similar giant cell reaction has recently been described in association with a uterine leiomyosarcoma, we are aware of only two other examples of this entity in the breast, both reported over 40 years ago in the French literature. This is the first report in which electron microscopy confirmed the benign histiocytic nature of the giant cells. These cells had many of the ultrastructural features of multinucleated giant cells described in tissue culture, skeletal osteoclastomas, and foreign body granulomas. We propose that the giant cells arise from fusion of mononucleated stromal cells, and most likely are reactive histiocytic elements which are in some way related to the tumor cell nests. Further studies of these unusual neoplasms are needed to determine if the giant cell reaction in any way affects the prognosis of the patient.

Adult↗
PubMed1977

Ligandinuria in nephrotoxic acute tubular necrosis.

Ligandin (GSH-S-transferase B), an abundant intracellular soluble protein in rat proximal tubules, hepatocytes, and small intestinal mucosal cells, is believed to be a component of an organic anion transport system. Its presence in urine was determined immunologically and catalytically in adult, female, Sprague-Dawley rats that were given mercuric chloride or potassium dichromate. These nephrotoxic agents produce severe renal failure, with epithelial necrosis in the proximal tubule. Mercuric chloride perferentially injures the terminal part of the proximal tubule, while potassium dichromate damages more proximal segments. Ligandinuria was consistently detected immunologically and catalytically from 6 to 24 hr following injection of mercuric chloride. Potassium dichromate administration did not result in immunologically detectable liganduria; however, GSH-S-transferase activity, which provides a more sensitive assay, was frequently detected. The findings are consistent with immunofluorescent localization of ligandin in the proximal tubule. Immunologic or enzymatic measurement of ligandin in urine may provide a sensitive index of acute injury to the proximal tubule.

Acute Kidney Injury↗