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Biomedical subjects

B Fleischer

Publications and source records attributed to B Fleischer.

At least 235 records · Page 13Linked to original sources
PubMed1983

Subcellular distribution of cholic acid:coenzyme a ligase and deoxycholic acid:Coenzyme a ligase activities in rat liver.

Cholic acid:CoA ligase (EC 6.2.1.7, choloyl-CoA synthetase) and deoxycholic acid:CoA ligase catalyze the synthesis of choloyl-CoA and deoxycholoyl-CoA from their respective bile acids in rat liver. A modification of the phase partition assay was introduced which yields significantly (3-fold) higher specific activities for cholic acid:CoA ligase than previously reported. An independent method of separating choloyl-CoA from the substrates by high-pressure liquid chromatography was also developed and validates the modification. Both enzymic activities were found to be localized predominantly in the endoplasmic reticulum of rat liver. The level of either ligase in other purified, active subcellular fractions is consistent with the level of contamination by endoplasmic reticulum, estimated by using marker enzymes. Hence, the ligase assay can be used as a sensitive enzymic marker for endoplasmic reticulum in rat liver. The kinetic parameters of both enzymic activities were determined by using purified rough endoplasmic reticulum from rat liver. While the apparent maximal velocities for the two substrates are similar, the Michaelis constant for deoxycholate is significantly lower than that for cholate. Taurocholate and deoxycholate are shown to be competitive inhibitors of cholic acid:CoA ligase. The inhibition constant of deoxycholate is similar to its Michaelis constant for the deoxycholoyl-CoA-synthesizing reaction, suggesting that the same enzyme is responsible for both ligase activities.

Animals↗
PubMed1983

Activation of human T lymphocytes I. Requirements for mitogen-induced proliferation of antigen-specific T lymphocyte clones.

In a model system for accessory cell (AC)-dependent mitogen-induced T cell proliferation the response of several human antigen-specific HLA-restricted helper T lymphocyte clones (HTLC) to mitogens was studied. It was found that the HTLC themselves did not or only weakly respond to various mitogens or to oxidation by galactose oxidase, but that the response could be strongly increased if certain tumor cell lines were added to the assay as AC. Pretreatment with lectins or oxidation of either HTLC or AC was effective in stimulating the proliferation of the T cells in this system. Reduction of the aldehydes formed during oxidation completely abolished the stimulatory activity of oxidized B lymphoblastoid cell line. This shows that cross-linking of T cell and AC is required to induce proliferation. When several established cell lines were tested for their capacity to function as AC in this system, profound differences in AC activity were detected. The inability of cells with poor AC activity to stimulate the HTLC was not due to trivial reasons, such as requirements for different mitogen concentrations, a decreased binding of mitogens or suppressive effects. Furthermore, AC activity was not dependent on the presence of Ia antigens on the AC. These findings are discussed with regard to the mechanism of mitogen-induced T cell activation.

B-Lymphocytes↗
PubMed1983

Clonal expansion and functional analysis of virus-specific T lymphocytes from cerebrospinal fluid in measles encephalitis.

T cells were directly cloned from the cerebrospinal fluid (CSF) of a patient with acute measles encephalitis by limiting dilution in the presence of irradiated feeder cells and T cell growth factor (TCGF). A total of 42 colonies was established. Functional analysis revealed 27 of them to be derived from a cytotoxic T lymphocyte as demonstrated by the ability to exert phytohaemagglutinin (PHA)-dependent cytotoxicity against uninfected allogeneic PHA blasts. Twenty-three of the cytotoxic colonies were specific for measles virus and restricted to self HLA-A or -B antigens. Three clones were also found to give measles virus-specific proliferative responses. The results show that the CSF in measles encephalitis contains a highly enriched population of in vivo sensitized antigen-specific T cells. We propose that the clinical symptoms in measles encephalitis are caused by a T cell-mediated reaction against virus-infected brain cells.

Child↗
PubMed1983

Human influenza virus-specific T helper cell clones can be restricted by MHC products different from serologically defined HLA-DR antigens.

Clones of human influenza A virus-specific T lymphocytes were generated by limiting dilution after several in vitro stimulations with autologous influenza A/USSR virus-infected cells. The clones were expanded in T cell growth factor and then grown only in the presence of antigen and irradiated stimulator cells. The clones showed antigen specificity in that they were stimulated only by cells infected with influenza A virus, but not with influenza B virus; some clones even showed distinct reactivity patterns with several influenza A virus subtypes. All clones had the OKT3+4+8-phenotype. Analysis of the restriction elements for the recognition of viral antigens, demonstrated that most clones recognized antigens associated with but not identical to serologically defined HLA-DR specificities. From the recognition pattern with HLA-DR typed donors, three different restricting antigens could be demonstrated.

Antigens, Viral↗
PubMed1983

Mechanism of glycosylation in the Golgi apparatus.

A major role of the Golgi apparatus in liver is the terminal glycosylation of secreted serum proteins and of plasma membrane glycoproteins. Galactosyltransferase is a membrane-bound Golgi enzyme that transfers galactose directly from uridine diphosphogalactose (UDP-Gal) to terminal N-acetylglucosamine groups of N-asparagine-linked glycoproteins during secretion. Sialytransferase then transfers sialic acid from cytidine monophosphosialic acid (CMP-NAN) to the newly added terminal galactose of the glycoprotein. In the cell, the transfer reaction must occur on the lumen side of the Golgi membrane. UDP-Gal is synthesized mainly in the cytoplasm and CMP-NAN is synthesized in the nucleus in liver. An important question for understanding the mechanism is, how do these nucleotide sugars gain access to the transferases? A second question involves uridine diphosphate (UDP), a highly inhibitory product of galactosyltransferase. How is UDP removed from the lumen of the Golgi fast enough to prevent product inhibition of the galactosyltransferase? We have shown that isolated Golgi, although vesiculated, retains its original orientation. The vesicles are oriented with greater than 90% of both galactosyltransferase and sialyl-transferase on the luminal side of the vesicles. Using intact vesicles, we can show that UDP-Gal is taken up via a saturable carrier system present in the Golgi membrane. During galactosylation in vitro, UDP formed in the lumen of Golgi vesicles is rapidly converted to UMP by a nucleoside diphosphatase in the lumen. Uridine monophosphate, which is much less inhibitory to the galactosyltransferase than UDP, is then transported out of the lumen by a second carrier and is broken down further to uridine by 5'-nucleotidase on the cytoplasmic side of the Golgi vesicles. The transport of nucleotides appears unique to the Golgi membranes, since neither rough endoplasmic reticulum nor plasma membrane vesicles from rat liver accumulate these nucleotides.

Animals↗
PubMed1983

Effector mechanisms against Rous sarcomas in quail.

The inhibitory effect on tumor growth of thymus-derived cells in the avian virus system has been demonstrated by several investigators. Here we report two kinds of experiments performed to test the role of various potential effector cells in the immune response against Rous sarcomas. In vivo experiments in Japanese quail using the antimacrophage agent silica implicate the macrophage as a further mechanism in the defense against Rous sarcoma virus-induced tumors. Induction of a nonspecific inflammation at the site of tumor development led to reduced tumor growth.

Animals↗
PubMed1983

Clonal analysis of HLA-restricted virus-specific cytotoxic T lymphocytes from cerebrospinal fluid in mumps meningitis.

T lymphocytes were cloned directly from the cerebrospinal fluid of a patient with mumps meningitis by limiting dilution in the presence of irradiated feeder cells and T cell growth factor. Of 84 colonies analyzed, 41 were cytotoxic, as shown by their ability to exert phytohemagglutinin-dependent killing. Of these, 39 showed specificity for the autologous mumps-virus infected target cells. The cytotoxic T cell colonies showed the same pattern of HLA restriction as bulk cultures of CSF lymphocytes. This study shows that it is possible to perform functional assays on inflammatory exudate cells at the clonal level. The data also suggest that recruitment of effector cells from the peripheral compartment into the meningeal spaces in mumps meningitis is highly antigen-specific.

Antibodies, Monoclonal↗
PubMed1983

Growth of antigen specific, HLA restricted T lymphocyte clones from cerebrospinal fluid.

Analysis of the local cell-mediated immunity within the central nervous system is limited by the small amount of material available. In the present report we describe that T lymphocyte clones can be expanded directly from the cerebrospinal fluid (CSF) using T cell growth factor and irradiated feeder cells. Without in vitro restimulation such clones can reproducibly be generated from fresh or cryopreserved CSF lymphocytes. From a patient with tuberculous meningitis, T lymphocyte clones were obtained that showed tuberculin (PPD) specific proliferative responses restricted by a single HLA-DR antigen. One of these clones was restricted by an antigen different from the serologically defined HLA-DR since this clone recognized PPD only on autologous but not on HLA-DR matched monocytes. These experiments show that T lymphocytes involved in the in situ immune response can be cloned directly from the site of inflammation.

Cells, Cultured↗
PubMed1982

Orientation and role of nucleosidediphosphatase and 5'-nucleotidase in Golgi vesicles from rat liver.

The fate of UDP formed during the galactosylation of added N-acetylglucosamine in Golgi vesicles isolated from rat liver using D2O-sucrose gradients has been determined. UDP-Gal labeled with [14C]uracil was used, and the products of the reaction were separated and quantitated by using high-pressure liquid chromatography. [14C]Uridine rather than [14C]UDP or [14C]UMP was found to accumulate, indicating the presence of both UDPase and UMPase activities in the Golgi. Golgi vesicles were shown to contain a nucleosidediphosphatase activity that is membrane bound. It appears to be located on the luminal face of the Golgi since it is activated 3-5-fold by detergents and 4-fold by treatment of the vesicles with Filipin. We have shown previously that Filipin disrupts the Golgi but does not solubilize membrane-bound enzymes. The nucleosidediphosphatase of the Golgi differs from that present in rough endoplasmic reticulum in its absolute requirement for Ca2+ for activity and in its substrate specificity that is higher for UDP than for IDP. Golgi vesicles also contain UMPase activity that is stimulated only 2-fold by detergents or Filipin. Concanavalin A inhibits this activity about 80% in both intact and detergent-treated vesicles. The Golgi UMPase is thus probably identical with 5'-nucleotidase. These results are consistent with histochemical evidence from other laboratories that indicate that 5'-nucleotidase is present on both sides of liver Golgi membranes. In the presence of concanavalin A and N-acetylglucosamine, intact Golgi vesicles were found to convert UDP-Gal to UMP. These findings indicate that UDP formed by galactosyltransferase in the lumen of the vesicles is rapidly converted to UMP by UDPase in the lumen but that UMP moves rapidly out of the lumen of the Golgi and is broken down to uridine by 5'-nucleotidase on the cytoplasmic side of the vesicles.

5'-Nucleotidase↗
PubMed1982

Mumps virus replication in human lymphoid cell lines and in peripheral blood lymphocytes: preference for T cells.

The replication of mumps virus was studied in human continuous lymphoblastoid cell lines (LCLs) with T or B characteristics and in lymphocyte subpopulations derived from peripheral blood. T-LCLs supported effective virus replication as shown by high titers of free and cell-associated virus over 1 to 4 days after infection. By immunofluorescence analysis, the majority of cells were positive for mumps virus antigens. In contrast, the B-cell lines produced low titers of infectious virus, and only a small percentage expressed viral antigens. This resistance of the B-LCLs was found with several mumps virus strains. Cultures of peripheral blood mononuclear cells also supported mumps virus replication. Very high titers of infectious virus (10(8) PFU/ml) were observed in cultures prestimulated with phytohaemagglutinin. Studies with enriched T and B cells point to the activated T lymphocyte as the major virus-producing cell.

B-Lymphocytes↗
PubMed1982

Cloned lines of human cytotoxic T lymphocytes with specificity for influenza virus.

The generation of human cytotoxic T cell clones with specificity for influenza virus and some of their characteristics are described. The clones were generated by limiting dilution of peripheral blood lymphocytes after two in vitro stimulations with autologous influenza A/USSR virus-infected cells and were grown in T cell growth factor. The majority of the virus-specific clones showed cross-reactivity for different influenza A virus subtypes but did not recognize influenza B virus-infected cells. The HLA specificity of two clones was further analyzed. One clone, LL33, was specific for HLA-Bw60, the other, clone WH5, for HLA-A1. Clone WH5 also seemed to recognize the serologically related HLA-A26 as restriction element for the recognition of the viral antigen. Whereas the virus-specific CTL clones had the OKT3+,4-,8+ phenotype, another clone, WH 49, exhibiting natural killer-like activity, was found to have the OKT3+,4+,8- phenotype.

Antigens, Viral↗
PubMed1982

[Surgical therapy of bronchial carcinoma in old age].

Between 1972 and 1981 436 patients with lung cancer underwent thoracotomy. 84 (19.2%) patients were aged 70 or more. 58.3% of this age group were in the tumor stage pT1-T2N0M0. In 82.1% a lobectomy was favored. The postoperative lethality among these 84 elderly patients was 19% caused by cardial insufficiency (68.8%) or postoperative pneumonia (25%). As a result of the high postoperative lethality in the elderly patient limited lung resection may be applied more often.

Adult↗
PubMed1981

[When must pulmonary tuberculosis be treated surgically even today?].

Out of 571 patients with a chest complaint 58 were operated on for TB of the lungs. The average age was 43. With the exception of 9 patients, who were suspected of having a primary carcinoma of the lung, the operation was basically carried out after unsuccessful antituberculostatic therapy. The need to operate has to take into account adequately not only the morphological and functional changes in the lungs but also the social circumstances of the patient. In 78,7% of operations resections of lung tissue were used. 66,7% lobectomies, 18,8% wedge dissections, 8,3% pneumectomies and 6,2% bilobectomies were carried out. There were no deaths after operations. Surgical therapy of TB of the lungs still plays an important part in the treatment of TB and its success is mainly dependent on the timing in accordance with the indication.

Antitubercular Agents↗
PubMed1981

Evidence for a Gp85-related glycoprotein in cells transformed by the Bryan high titer strain of Rous sarcoma virus.

The Bryan High Titer strain of Rous Sarcoma Virus (BH-RSV) is a deletion mutant in the env-gene coding for the viral envelope glycoproteins gp35 and gp85. In this report experimental evidence is described that cells, transformed by BH-RSV, express a glycoprotein immunologically related to gp85. Animals bearing BH-RSV induced tumors produce antibodies reacting with gp85 of nondefective RSV. Lysates of a BH-RSV transformed quail cell line, R(-):Q, inhibit the immunoprecipitation of gp85 by antibodies against the group-specific determinant of gp85. In R(-):Q cell lysates and in the culture supernatant a glycoprotein of an apparent molecular weight 40,000 (gp40) is found that reacts with monospecific antisera against gp85 of nondefective RSV. In newly synthesized BH-RSV a gp40 associated with the virion is detectable but is easily lost during purification of the virus. Further, a 95k glycoprotein and a 95k phosphoprotein are specifically precipitated from R(-):Q cells by an antiserum against gp85. From these results we conclude that the deletion of the env-gene is incomplete such that part of gp85, bearing group-specific antigenic determinants, is expressed in BH-RSV transformed cells. Analysis of BH-RSV particles freshly harvested from R(-):Q cells reveals that they contain almost exclusively the gag-precursor pr76 and little or no processed gag-proteins. Therefore the R(-):Q cell line seems to be suitable for the study of virus maturation occurring after the budding process.

Animals↗