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Biomedical subjects

M Reinacher

Publications and source records attributed to M Reinacher.

At least 55 records · Page 3Linked to original sources
PubMed1987

Immunohistochemical demonstration of decreased L-pyruvate kinase in enzyme altered rat liver lesions produced by different carcinogens.

Preneoplastic liver lesions were produced in female Wistar rats by application of 25 mg/kg N-nitrosomorpholine (NNM), 14 mg/kg diethylnitrosamine (DENA), 0.075 mg/kg aflatoxin B1 (AFB1) or 160 mg/kg safrole. These carcinogens were administered in two equal doses 12 and 24 h after partial hepatectomy. The animals then received sodium phenobarbital (0.1% in tap water) for up to 410 days. Numerous altered hepatic foci (AHF) and hyperplastic nodules (HN) were detected enzyme histochemically by their negative ATPase reaction after application of AFB1, DENA and NNM; some AHF and HN were also caused by the weak carcinogen safrole. Immunohistochemically these lesions were also L-pyruvate kinase (L-PK)-negative with a high coincidence with regard to their number and area. These results confirm the role of L-PK, an enzyme affecting the pentose phosphate pathway, as a negative marker of preneoplastic liver lesions.

Animals↗
PubMed1987

Synergistic role of staphylococcal proteases in the induction of influenza virus pathogenicity.

Several strains of Staphylococcus aureus have been found to secrete proteases that activate infectivity of influenza virus by proteolytic cleavage of the hemagglutinin. The enzymes of the bacterial strains Wood 46 and M 86/86 have been characterized in some detail and were found to be serine proteases. In their substrate specificities and inhibitor sensitivities they proved to be similar to, but not identical with trypsin and plasmin. The hemagglutinin of an individual virus strain could be cleaved by the proteases of some but not all staphylococcal strains, and a given enzyme could cleave only some but not all hemagglutinins analyzed. When mice were coinfected intranasally with the appropriate strains of influenza virus and S. aureus, the hemagglutinin was readily activated allowing multiple cycles of virus replication in the lung. Under these conditions, the animals came down with a fatal disease exhibiting extended lesions in the lung tissue. In contrast, after infection with virus or bacteria alone, there were no significant pathological changes. When the staphylococcal strain did not contain a protease that was able to activate the hemagglutinin of the coinfecting virus strain, the animals did not exhibit disease. These observations demonstrate that coinfecting bacteria can play an essential role in the development of influenza pneumonia by providing a protease suitable for cleavage activation of the hemagglutinin.

Animals↗
PubMed1987

Feline leukemia virus-associated enteritis--a condition with features of feline panleukopenia.

Infection with feline leukemia virus (FeLV) was demonstrated immunohistologically in 218 necropsied cats suffering from enteritis. The animals were divided into three groups according to histopathological criteria. The first group exhibited the signs of feline panleukopenia in intestine, lymphoid tissues, and bone marrow. Only 1.6% of these animals were FeLV-infected. The animals of the second group had histopathological alterations as seen in cats suffering from feline panleukopenia, but these were found only in the intestine and not in lymphoid tissues or bone marrow. Of these 71.9% were infected with FeLV. The third group consisted of all other cats suffering from enteritis of which 6.3% were FeLV-positive. The association between FeLV infection and the lesions seen in the animals of group 1 (feline panleukopenia) and group 3 (other types of enteritis) is statistically not significant whereas the alterations exhibited by the cats of group 2 are significantly FeLV-associated. Cats with FeLV-associated enteritis (group 2) are of a mean age of about 2.5 years and are significantly older than animals with feline panleukopenia which are of a mean age of about half a year. Thus a FeLV-associated enteritis exists as a histopathologically recognizable condition which sometimes might be mistaken for feline panleukopenia in routine post-mortem investigations.

Animals↗
PubMed1987

Frequency and significance of feline leukemia virus infection in necropsied cats.

Feline leukemia virus (FeLV) infection was diagnosed immunohistologically on paraffin-embedded tissues obtained from 1,095 necropsied cats. Significant association of FeLV infection was demonstrated by chi 2 and Fisher's tests with various conditions and diseases (ie, anemia, tumors of the leukemia/lymphoma complex, feline infectious peritonitis, bacterial infections, emaciation, FeLV-associated enteritis, lymphatic hyperplasia, and hemorrhage). Unexpected findings associated with FeLV infection were icterus, several types of hepatitis, and liver degeneration. A negative association with FeLV infection was found for most parasitic and viral infections, including feline panleukopenia. Neither positive nor negative associations were established for FeLV infection and most forms of nephritis, including severe glomerulonephritis. Feline leukemia virus-infected cats were significantly (Kruskal-Wallis test) older than were FeLV-negative cats with the same nonneoplastic FeLV-associated diseases.

Animals↗
PubMed1987

Human erythrocyte pyruvate kinase (L'/R-PK): production and characterization of a monoclonal antibody.

Two preparations of L'/R-type pyruvate kinase from human erythrocytes characterized by SDS-PAGE were used for immunization of BALB/c mice. Their spleen cells were fused with mouse myeloma cells by polyethylene glycol according to standard techniques. Supernatants of hybridomas resulting from two separate experiments were assayed by ELISA and further characterized by immunoblotting. Using those monoclonal antibodies reacting with L'/R-PK in immunoblotting, a major band of 62 KDa MW was recognized in both preparations employed for immunization. Additionally, four smaller bands were detected. Furthermore, the monoclonal antibodies also detected a single band of 62 KDa MW in a highly purified L-PK prepared from human liver. In contrast, they showed no reaction with muscle and brain tissues containing M1-type PK. However, they reacted strongly with a single band of approximately 62 KDa in liver and kidney homogenates which is in line with immunocytochemical studies showing immunoreactive material in hepatocytes and proximal tubules of the kidney.

Antibodies, Monoclonal↗
PubMed1986

Localization and role of pyruvate kinase isoenzymes in the regulation of carbohydrate metabolism and pyruvate recycling in rat kidney cortex.

This work was performed to gain more information on the role of pyruvate kinase isoenzymes in the regulation of renal carbohydrate metabolism. Immunohistochemically, pyruvate kinase type L is shown to be localized in the proximal tubule of the nephron and pyruvate kinase type M2 in the distal tubule and the collecting duct. a tight relationship between gluconeogenesis and pyruvate recycling was found. The rate of gluconeogenesis (8 mumol/g wet wt. per 30 min) was of the same order of magnitude as the rate of pyruvate recycling (10.92 mumol/g wet wt. per 30 min). Stimulation of gluconeogenesis from 20 mM lactate in kidney cortex slices of 24-h-starved rats by dibutyryl-cAMP, alanine and parathyroid hormone was connected with a decrease in pyruvate recycling; inhibition of gluconeogenesis due to a lack of Ca2+ in the incubation medium was linked with an increase in pyruvate recycling. The degradation of [6-14C]glucose to lactate, pyruvate, ketone bodies and CO2 and of [2-14C]lactate was unaffected by dibutyryl-cAMP, alanine, epinephrine, vasopressin or the omission of Ca2+ from the incubation medium. 1 mM dibutyryl-cAMP or 5 mM alanine did not alter the activities of oxaloacetate decarboxylase, 'malic' enzyme and malate dehydrogenase from rat kidney cortex. Since aerobic glycolysis in the distal tubules and the collecting ducts is not influenced by hormones, dibutyryl-cAMP and Ca2+, pyruvate kinase type M2 residing in this tissue is unlikely to be a control point of glycolysis. Since this tissue degrades only one-seventh of the glucose formed via gluconeogenesis, it does not contribute significantly to pyruvate recycling. Therefore, the decrease of pyruvate recycling in the presence of dibutyryl-cAMP and alanine in rat kidney cortex slices, leading to increased renal gluconeogenesis, has to be ascribed to the regulation of pyruvate kinase type L.

Alanine↗
PubMed1986

Monoclonal antibodies directed towards the two major cell populations in the bursa of Fabricius of the chicken.

Two mouse monoclonal IgM antibodies, B.1 and B.2, have been produced using the mouse myeloma cell line Sp2/0-Ag 14 and spleen cells from mice immunized with chicken bursa cells. The binding of the monoclonal antibodies to cells in suspension or tissue sections was demonstrated by means of the unlabeled peroxidase-antiperoxidase method. B.1 recognizes 61% of the bursa cells, 10-14% of the cells of spleen and of the peripheral mononuclear blood leukocytes and 1% of the thymus cells. The B.1+ cells are regarded as B cells. Their location in tissue sections corresponds with the known B-dependent areas of lymphoid organs. Competitive binding and double marker experiments proved that the B.1 antigen is distinct from surface immunoglobulin (Ig). In the bursa all B.1+ cells are also Ig+, whereas in the thymus, spleen and blood only about 90% of the B.1+ cells show this conformity. B.2 mainly recognizes so called reticular epithelial and reticular cells of the bursa (36%), thymus (20%) and spleen (13%). The B.2+ cells represent the second major cell population of the bursa.

Animals↗
PubMed1986

Pyruvate kinase isoenzymes in altered foci and carcinoma of rat liver.

Pyruvate kinase (PK) isoenzymes, rate limiting for the last steps of glycolysis, were studied in normal rat liver, putative preneoplastic foci, neoplastic nodules and hepatocellular carcinoma. These lesions were produced by an initiation-promotion protocol: treatment with a single dose of N-nitrosomorpholine (NNM) was followed by feeding diets containing phenobarbital (PB) or alpha-hexachlorocyclohexane (alpha-HCH), or basal diet. PK was demonstrated (i) by immunocytochemistry on histological sections with antibodies specifically directed against the L and M2 isoenzymes, (ii) by electrophoretic separation of isoenzymes in homogenates from liver and larger tumors, and (iii) by electrophoretic separation of isoenzymes in parenchymal and stromal cells isolated from liver and tumors. Immunocytochemistry showed decreases of L-PK (L-PK-) in hepatocytes of most of the foci, nodules and carcinomas. Most L-PK- foci showed increases in gamma-glutamyltransferase (gamma-GT) and epoxide hydrolase (EH). PB or alpha-HCH treatment further decreased expression of L-PK in foci, but not in normal liver. Cells and foci with enhanced L-PK (L-PK+) were also found after carcinogen treatment. These did not show increases of gamma-GT or EH or any distinct morphological alterations with the exception of some which were basophilic ('tigroid') in H and E stained sections. No L-PK+ tumors were found. We could not demonstrate the M2-type PK in parenchymal cells of liver or any of the lesions described above. This isoenzyme was restricted to stromal cells in normal rat liver and in all stages of carcinogenesis as shown by immunohistology and by electrophoresis of preparations from isolated cell populations. However, stromal cells from hepatocellular carcinomas exhibited a 3-fold increase of M2-PK compared with stromal cells from normal liver. These results do not support an isoenzyme shift from L to M2-PK in the course of malignant transformation of hepatocytes as suggested previously.

Animals↗
PubMed1986

Carbohydrate metabolism in neoplastic tissue.

The kinetic and immunological properties of purified, homogeneous pyruvate kinase type M2 from chicken lung and tumors, including that of Rous sarcoma virus transformed chicken fibroblasts, have been compared. The type M2 enzymes from both lung and tumors have immunologically distinct structures. The enzyme isolated from tumors is characterized by a low affinity for phosphoenol pyruvate, pronounced L-serine activation and a strong inhibition by L-alanine, L-proline and several other amino acids. The chicken lung enzyme is only slightly affected by serine. The cellular amino acid concentration is in such a range that the tumor enzyme is strongly inhibited whereas the lung enzyme is only partially inhibited. The characteristics of the tumor enzyme allow the optimal adaptation to lactic acid and production of energy from glucose or amino acids dependent on substrate and oxygen supply.

Amino Acids↗
PubMed1984

Immunomorphologic characterization of chicken thrombocytes.

Chicken thrombocytes were enriched for immunization by utilizing their strong capacity to adhere to plastic surfaces. The produced rabbit anti-thrombocyte serum ATS 3 reacted by means of the unlabeled antibody enzyme method (PAP) specifically with thrombocytes of fixed chicken-blood smears, but not with lymphocytes or other blood cells. When ATS 3 (substrate diaminobencidinetetra-hydrochloride = DAB) and a 1.1 mixture of an anti-bursa serum and anti-thymus serum (ABS/ATS; substrate 4-chloro-1-naphthol = 4-Cl-1-N) were used simultaneously, thrombocytes revealed the brown color typical for DAB, whereas lymphocytes showed the blue stain of 4-Cl-1-N. The finding of a thrombocyte surface antigen not shared by lymphocytes is regarded as a further proof of the diversity of both cell systems, i.e., for the existence of a genuine thrombocyte system in chickens.

Animals↗
PubMed1983

Pyruvate kinase type M2 is phosphorylated in the intact chicken liver cell.

Isolated hepatocytes from 24 h starved chicks were depleted of phosphate and incubated in the presence of 32P-orthophosphate. Pyruvate kinase type M2 from crude cell extracts was partially purified by chromatography on DEAE-Sephacel and hydroxylapatite. SDS slab gel electrophoresis of the fractions containing the enzyme and immunoprecipitation with antisera showed the phosphorylation of pyruvate kinase type M2. Phosphoamino acid analysis identified serine as phosphate acceptor.

Amino Acids↗
PubMed1983

Pathogenesis of neurovirulent influenza A virus infection in mice. Route of entry of virus into brain determines infection of different populations of cells.

Coinfection of a cell culture with a human and avian influenza A virus had yielded a recombinant virus with high neurovirulence for mice. This study reports on the comparative pathogenesis of central nervous system infection in mice between the parental human and the recombinant virus using the immunohistologic peroxidase-antiperoxidase method and virus assay of tissue suspensions. The human virus replicated poorly in mice and did not replicate in the brain even after intracerebral inoculation. In contrast, the recombinant virus replicated to high titer in the lung and brain with resulting viremia after inoculation of young mice by the intracerebral, intraperitoneal, or intranasal routes. Different populations of cells in the brain became infected after inoculation by each of the three routes: choroid plexus, and ependymal and subependymal cells after intracerebral inoculation; cells in perivenous areas, neurons in the olfactory bulbs and trigeminal ganglia and nuclear groups in the brainstem and midbrain after intranasal inoculation. Intraperitoneal inoculation resulted almost exclusively in the perivenous spread of the virus. The intranasal inoculation suggested that virus entry into the brain both by spread along nerve cell processes from the nasal mucosa to the brain and trigeminal ganglia and subsequent perivenous spread after viremia developed following virus replication in the lung. To dissect these two mechanisms we inoculated neonatal mice that had acquired high levels of serum antibody by nursing from actively immunized mothers. Intraperitoneal inoculation of these mice failed to cause infection, whereas intranasal inoculation resulted in the same pattern of cellular spread through the olfactory and trigeminal pathways as noted previously. This proved that this recombinant influenza virus could invade the central nervous system after infection via a natural route of infection. This highly neuroinvasive agent provides one example of the extent of virulence which can be acquired by recombination of apathogenic influenza viruses and raises a note of caution for adequate control of those agents generated in the laboratory.

Animals↗
PubMed1982

Japanese quail embryo cell line persistently infected with erythroblastosis virus.

A Japanese quail embryo cell line transformed by avian retrovirus, designated QERC-31F, was further characterized in virological and cytological aspects. Infectious virus produced by this cell line was found to belong to subgroup A. The virus failed to transform quail embryo cells, whereas it induced erythroblastosis by injection into neonatal quails. Injection of QERC-31F cells into neonatal quails resulted in the induction of solid tumors which morphologically diagnosed as undifferentiated sarcoma. Mitosis of pro-erythrocytic cells with also detected in the peripheral blood of the tumor bearing animals. Antiserum to chicken erythrocyte histone V fraction which was also shown to react specifically with the nucleus of quail erythrocytes stained the nucleus of QERC-31F cells. These results suggested that this cell line maintains characteristics of the erythroblast and possibly produces avian erythroblastosis virus as well as helper virus of subgroup A.

Alpharetrovirus↗