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Biomedical subjects

G Klein

Publications and source records attributed to G Klein.

At least 1,009 records · Page 56Linked to original sources
PubMed1978

[Treatment of acute myocardial infarction with metoprolol (author's transl)].

Metoprolol, a cardioselective beta-receptor blocker, was administered to 12 patients three to ten hours after sustaining a transmural myocardial infarction, and the effect of the drug (10 mg i.v., followed by 50 mg orally every eight hours) was followed for 48 hours. Heart rate decreased by 16% and cardiac output by 27%, while blood pressure and stroke volume decreased little and pulmonary "wedge" pressure was not significantly changed. Even in patients with initially definitely elevated left-ventricular filling pressure (greater than 20 mm Hg) the drug was well tolerated without any further rise in pressure. Since left-ventricular work was significantly decreased (stroke work--15%, cardiac output--31%) and the duration of diastole, decisive for coronary perfusion, was prolonged, it is concluded that early administration of beta-receptor blockers has a favourable effect on myocardial oxygenation and possibly reduce ultimate infarct size.

Acute Disease↗
PubMed1978

Production of rabbit antibodies against the viral capsid antigen (VCA) of the Epstein-Barr virus (EBV).

Rabbits were immunized with nuclear or cytoplasmic extracts of the Epstein-Barr virus (EBV)-producing marmoset cell line B95-8. Following extensive absorption with human EBV-negative cells (HeP-2, Ramos and BJAB), sera were obtained that no longer reacted with cellular or serum proteins of human origin, but gave a single precipitin band with extracts of the human EBV-producing line, P3HR-1. Immunofluorescence tests performed with appropriate parallel human serum controls showed that the rabbit serum contained no activity against EBNA + EA - VCA - Raji cells, or against P3HR-1 virus superinfected, cytosine arabinoside-treated Raji cells that contained EBNA and EA, but not VCA. The sera gave a brilliant indirect immunofluorescence reaction with the virus-producing (EBNA+ EA+ VCA+) P3HR-1 lines. Two-color fluorescence tests, performed with a direct TRITC-labelled VCA conjugate and indirect FITC-staining with the rabbit serum, showed that the same cells reacted in both red and green fluorescence, confirming that the rabbit serum was directed specifically against some antigen formed in the virus-producer cells. Since the synthesis of the relevant antigen was prevented by cytosine arabinoside it cannot be EA and must be a late antigen. The morphology and localization of the antigen support the conclusion that the antigen is VCA or some part of the VCA complex.

Animals↗
PubMed1978

[Mode of action of cardiovascular drugs. Echocardiographic studies (author's transl)].

Echocardiography--combined with additional non-invasive methods--has proved a sensitive tool for measuring hemodynamic and left ventricular function parameters. This study was undertaken to measure by these methods the effect of digoxin, isoproterenol, of the beta-receptorblocker sotalol, sodium nitroprusside and isosorbide dinitrate on the hemodynamics and left ventricular contractility in various patients and normal volunteers. Besides the good reproducibility of results of recent invasive investigations, partly in animal experiments, new aspects about the mode of action of the individual substances were obtained.

Cardiovascular System↗
PubMed1978

Increased immunogenicity of low-antigenic rat tumors after superinfection with endogenous murine C-type virus in nude mice.

Four chemical carcinogen-induced and two polyoma-virus-induced rat tumors were repeatedly passaged through nude mice. A methylcholanthrene-induced tumor in BDIX rats (MBDB) and a polyomavirus-induced tumor in Wistar/Fu rats (PW41) became infected with endogenous mouse virus (EMV), as judged by the expression of murine C-type virus-associated gp71, p30 and p12 antigens on their cell surface. Two ethylnitrosourea-induced tumors in BDIX rats (290T and GE3A) were exposed in vitro to the supernatant of EMV-infected PW41. Subsequently, 290T but not GE3A converted to murine gp71, p30 and p12 positivity. All these successfully infected rat tumors (EMV-MBDB, EMV-PW41 and EMV-290T) became less transplantable to and more rejectable in otherwise susceptible syngeneic rats. To compare the immunogenicity of the virus-infected and non-infected tumors, syngeneic rats were immunized three times with irradiated cells, and challenged with the non-infected tumor. Wistar/Fu rats immunized with irradiated EMV-PW41 showed no improvement in PW41 rejection, compared to rats immunized with irradiated, non-infected cells. On the other hand, BDIX rats immunized with EMV-MBDB or EMV-290T rejected MBDB or 290T, respectively, with no cross-immunity, while the rats immunized with irradiated but non-infected tumors showed no significant rejection. These results indicate that EMV infection augmented the immunogenicity of non-immunogenic or only low-immunogenic rat tumors.

Animals↗
PubMed1978

Shedding of anti-IgM from antibody-coated human lymphoma lines: differences between Epstein-Barr virus-negative lines and their virus-converted sublines.

In vitro converted, Epstein-Barr (EBV) genome-carrying cell lines showed a reduced ability to shed surface-bound antibodies, compared to their EBV-free parental B lymphoma lines. On the other hand, antibody degradation was higher with EBV-positive cells. Analysis of antibody-coated single cells revealed that cells which failed to redistribute or cap their ligand-bound surface components at 37 degrees C, were also capable of shedding bound antibody. This suggests that capping and shedding are essentially independent phenomena, although both may be influenced by the same virally induced change in the lateral mobility of membrane constituents.

Antibodies, Anti-Idiotypic↗
PubMed1978

Activation of the alternative complement pathway by human B cell lymphoma lines is associated with Epstein-Barr virus transformation of the cells.

Activation of the alternative complement pathway by human B cell lymphoma lines is correlated with the presence of Epstein Barr virus (EBV) in the cell genome. EBV-negative B cell lymphoma lines produce little activation of the alternative pathway as measured either by C3 deposition on the cell surface or C3 conversion and consumption of alternative pathway activity in the supernatant serum. By contrast, EBV-positive sublines derived by in vitro EBV conversion of EBV-negative parental lines produce considerable activation of the alternative pathway. This membrane-associated complement-activating mechanism reflects an EBV-induced membrane change in these cells and may provide a mechanism whereby EBV-transformed cells are controlled in vivo.

B-Lymphocytes↗
PubMed1978

Somatic cell hybrids between human lymphoma cell lines. V. IdUrd inducibility and P3HR-1 superinfectability of Daudi/HeLa (DAD) and Daudi/P3HR-1 (DIP-1) cell lines.

We have studied two types of somatic cell hybrid with regard to expression of the Epstein-Barr virus (EBV) cycle and its regulation. The first, DIP-1, a hybrid formed between two human lymphoma EBV producers (Daudi and P3HR-1), contained EBV DNA, expressed the virus-determined nuclear antigen (EBNA), andwas a producer of the EBV-associated antigens EA (early antigen) and VCA (viral capsid antigen). The second, DAD, a hybrid series of clones formed between Daudi and a HeLa cell derivative (D98), differed with regard to the expression of EBNA, EA, VCA and the content of EBV DNA. EA was regularly induced in the EBV DNA-containing hybrids following treatment with iododeoxyuridine (IdUrd). This induction was greater in lines spontaneously expressing EA. In two hybrids, DIP-1 and DAD10, VCA and virus DNA synthesis were also induced in the presence of IdUrd, the latter being detected by in situ hybridization with P3HR-1 EBV complementary RNA. Finally, while DIP-1 was superinfectable by the P3HR-1 EBV strain, the DAD series of hybrids were refractory to P3HR-1 superinfection and lacked EBV receptors.

Antigens, Viral↗
PubMed1978

Epstein-Barr virus in somatic cell hybrids between mouse cells and human nasopharyngeal carcinoma cells.

Somatic cell hybrids between mouse cells and cells derived directly from NPC biopsies were produced in order to study the association of the Epstein-Barr virus (EBV) genome and the expression of Epstein-Barr nuclear antigen (EBNA) with the human chromosome(s). All attempts to correlate the presence of EBV-DNA and the expression of EBNA with the presence of a particular human chromosome(s) showed that the segregation of EBV-DNA or of EBNA and human chromosomes was dysconcordant. The data, therefore, suggest that in the hybrids studied the presence of EBA-DNA is not determined by the presence of a specific human chromosome.

Animals↗
PubMed1978

The HLA-dependent expression of testis- organizing H-Y antigen by human male cells.

The proposal that the stable expression of organogenesis-directing plasma membrane antigens, such as testis-organizing H-Y antigen, requires beta2-microglobulin-MHC antigen dimers as anchorage sites was tested on Daudi human Burkitt lymphoma cells [46, XY, 15q-, 14q+, beta2-m(-), HLA(-)]. The H-Y antigen level of Daudi was only 20% of that of Raji and Ramos, two human male pseudodiploid Burkitt lymphoma lines that were beta2-m(+), HLA(+). When Daudi is hybridized with beta2-m(+), HLA(+) cell lines, beta2-microglobulin, supplied by the latter, is known to restore the expression of Daudi HLA antigens A10 and BW17. Such restoration of HLA antigen expression markedly elevated H-Y antigen levels in those somatic hybrids. Thus the H-Y antigen level of the Daudi x Raji 8A (male X male) hybrid became equal to that of TetraRaji--the colcemide-induced Raji tetraploid line. Two independently derived Daudi x Hela D98 (male x female) hybrids, DAD 1 and DAD 10, demonstrated even higher H-Y antigen levels comparable to that of normal male peripheral blood lymphocytes.

Antigens↗