Search PubMed⌕ Search

Biomedical subjects

W Zimmermann

Publications and source records attributed to W Zimmermann.

At least 199 records · Page 11Linked to original sources
PubMed1983

Studies on the SV40-like papovavirus SV40-GBM. II. Molecular cloning in Escherichia coli of variant DNA molecules from glioblastoma-derived virus.

The complete DNA genomes of the SV40-like GBM virus (GBM1), isolated from a human glioblastoma multiforme, and of two discrete classes of GBM DNA molecules that appear following three passages in CV-1 monkey cells at low multiplicities (GBM3-H and GBM3-L), were cloned in Escherichia coli using plasmid vector pBR322. The cloned viral DNAs were characterized (i) by digestion of the chimeric plasmid DNAs with various restriction enzymes followed by comparison of their electrophoretic mobilities in agarose with that of similarly digested uncloned DNA, (ii) by hybridization of digested chimeric plasmid DNAs to 32P-labeled uncloned GBM DNA, and (iii) by electron microscopy. In restriction enzyme analysis the cloned GBM DNAs showed the same cleavage pattern as the uncloned DNAs, indicating that no major insertions or deletions were present. The electrophoretic data were confirmed by electron microscopic heteroduplex analysis.

Cloning, Molecular↗
PubMed1983

Studies on the SV40-like papovavirus SV40-GBM. I. Genomic analysis by restriction endonucleases and electron microscopy after propagation in CV-1 monkey cells.

Infection of CV-1 monkey cells with SV40-GBM, a papovavirus isolated from a human glioblastoma multiforme, resulted in the appearance of defective viral DNA molecules. In contrast to SV40 wild-type, two main types of variant DNA molecules could be found after three viral passages at multiplicities of infection of about 10. The molecules of one variant DNA (GBM3-L) were about 19% shorter than the GBM3-H DNA molecules and the DNA of the original GBM isolate, as demonstrated by electron microscopy. Restriction enzyme analysis revealed that GBM3-L DNA had lost both the EcoRI and the HpaII cleavage sites which are located in the late viral genome region. Furthermore, SV40 GBM3-L did not possess the two PvuII sites which are located in the late genome region, and a portion of the GBM3-H and GBM3-L DNA molecules had lost the unique KpnI site. Heteroduplex analysis verified that the rearrangements in the GBM3-L DNA are located only in the late region of this DNA. The possible differences between SV40 wild-type and SV40-GBM are discussed on the basis of these results.

Animals↗
PubMed1983

Characterization of messenger RNA specific for carcinoembryonic antigen.

Total poly(A)-containing RNA extracted from a rectal carcinoma was translated in a rabbit reticulocyte lysate. By addition of either a monoclonal or a polyclonal antibody, both monospecific for carcinoembryonic antigen, one protein with an apparent molecular weight of 85,000 was specifically precipitated, as shown by electrophoresis of the immunoprecipitate on sodium dodecylsulfate polyacrylamide gels. This protein behaves similarly to CEA isolated from liver metastases of a colon tumor in its property of being resistant to cleavage by cyanogen bromide. These findings suggest that this protein represents the CEA precursor protein. When we consider the high carbohydrate content of 60% of CEA, the observed molecular weight of the CEA precursor protein is in agreement with the reported molecular weight of 180,000 for CEA. By sedimentation of poly(A)-containing tumor RNA through a sucrose gradient, and by in vitro translation of each fraction of the gradient, the sedimentation coefficient of CEA-specific mRNA was found to be about 22 S.

Animals↗
PubMed1983

Enzyme immunoassay for swine trichinellosis using antigens purified by immunoaffinity chromatography.

Various preparations of crude and a purified preparation of Trichinella spiralis antigens were compared in a rapid, micro-enzyme immunoassay (EIA) for detecting trichinellosis in swine. The crude antigen preparations (XM-300 or S3 fraction) were lipid-free, cell-free fractions of muscle larvae, and the purified antigen was prepared by immunoaffinity chromatography of the soluble fraction of stichocyte secretory granules from rat muscle larvae. The antigens were tested against normal and immune swine sera for sensitivity and specificity, and for their ability to detect seroconversions early in the immune response. At optimum concentrations, absorbance values from immune and nonimmune sera produced sample to noise (S/N) ratios three-fold higher for the column antigen than for XM-300. Tests of sequential sera from experimentally-infected pigs showed that the column antigen produced lower absorbances with pre-infection sera and, from 18 days post-infection, higher absorbances with positive sera. From 21-28 days post-infection, absorbances and S/N ratios with column antigen were nearly twice those with XM-300. Column antigen detected antibodies more often than XM-300 antigen in sera collected prior to the appearance of larvae. Crude antigen did not distinguish all true negatives from weakly positives in a study involving 100 sera from muscle digestion-negative pigs and 75 sera from experimentally infected pigs, whereas the column antigen distinguished all negatives from positives. In a larger scale test of the column antigen, 1,130 pigs from Puerto Rico were tested in the micro-EIA test. Puerto Rico has no endogenous trichinellosis, and all 1,130 pigs were shown to be muscle digestion negative. These same pigs were all negative using the column antigen. These results show that the column antigen out-performs the crude antigens in sensitivity, specificity, and early detection. The column antigen is therefore a major improvement in the EIA for swine trichinellosis.

Animals↗
PubMed1983

Immortalization of human Lesch-Nyhan-fibroblasts following infection with Simian virus 40.

Skin fibroblasts of three Lesch-Nyhan patients were successfully transformed to unrestricted growth by Simian virus 40. The transformed character of isolated clones was confirmed by their epitheloid growth in medium containing low concentration of serum, by hyperdiploid karyotype patterns, by detection of SV40 T-antigen, by their growth in soft agar and by the proliferation of cells in vitro up to 200 passages hitherto.

Animals↗
PubMed1983

Evolutionary relationships between papovaviruses and their hosts.

The papovaviridae family consists of two genera, the papillomaviruses (PV) and the polyomaviruses (Py-V). Both genera are distinguished by morphological (larger sizes of the PV) and several biological characteristics. The genomes of either of the two genera share highly conserved DNA regions and a common antigenic determinant, located in their major capsid polypeptides. On the basis of these data an evolutionary relationship among the members of PV and Py-V, respectively, has been suggested. No homology has been found for either DNA- or protein sequences between PV and Py-V and the question of a common ancestor for both viral genera remains open. We have started to characterize the genome of a papilloma producing papovavirus of the Syrian hamster (HaPV). Most of the known biological characteristics of the HaPV suggest it should be classified as a papilloma-like virus. However, the molecular weight of about 3.5 X 10(6) daltons found for the circular duplex DNA lies within the range given for SV 40 and polyoma virus (Py). Analysis of the HaPV genome by cleavage with 21 different restriction endonucleases, location of specific binding sites of phage T 4 gene 32 protein and E. coli RNA polymerase on the viral DNA demonstrated that the HaPV differed distinctly from all other currently known papovaviruses. The HaPV genome was also analyzed by filter hybridization and electron microscopy under conditions of varied stringency for nucleotide sequence homology with the genomes of different papovaviruses of both genera. Whereas no homologous DNA regions could be found between the genomes of HaPV and the human PV types 1 and 4, only under nonstringent conditions (Tm-43 degrees C) stable hybrids were formed between HaPV-, SV 40- and the DNA of a PV isolated from Mastomys natalensis (MnPV). On the other hand extensive homology was detected between the genomes of HaPV and Py even under stringent hybridization conditions (Tm-28 degrees C). The homologous DNA segments mapped on the Py and partially on the SV 40 genome were found to be the most strongly conserved DNA regions among the Py-V genus. These results are discussed with respect to a classification of the HaPV within the papovaviridae family.

Animals↗
PubMed1983

Quantitative determination of papovavirus IgG antibodies in sera from cancer patients, labworkers and several groups of control persons by enzyme-linked immunosorbent assay (ELISA).

An enzyme-linked immunosorbent assay (ELISA) for detection of specific IgG antibodies against the capsid antigen of SV40 and SV40-GBM is described. We have determined the presence of SV40 and SV40-GBM IgG antibodies, respectively, in sera of labworkers who are in intensive or rare contact to SV40, in sera of tumor patients as well as in sera of different control persons. In 13% of the sera of the control group antibodies against SV40 were found, when the persons were born 1962 or later. They received SV40-free poliomyelitis vaccine. On the other hand 24% of the sera were positive when the people were born between 1959-61 and probably received SV40-contaminated poliomyelitis vaccine. A similar percentage of positive sera (21-32%) were found in cancer patients suffering on different tumors. Also 29% of the sera of labworkers, born before 1955 and with rare contact to SV40 reacted positive. However, 55% of the sera of labworkers had positive sera when they were in intensive contact to SV40. The results presented and discussed in the light of SV40 as a possible risk factor for the human population.

Adult↗
PubMed1983

[Diagnosis of asocial, aggressive behavior--experiences with Petermann and Petermann's "EAS"].

This article describes the testing and first application under standardized conditions of Petermann and Petermann's psychometric test for assessing aggressive social behaviour in specific situations among children aged 9 to 11 years in the GDR. Experience gained in using the test is reported, and orientational scores are given as a first step towards restandardization for this age span. The possibility of standardizing the test for application in the GDR is discussed, and proposals are made to broaden the test (especially by the development of an appropriate scoring scale). The connections between the scores and a few other important test variables are discussed, and the author shows clearly that the results of the test and the answers given depend on the "tendency to social desirability".

Aggression↗
PubMed1982

Deoxyribonucleic acid synthesis in isolated chloroplasts and chloroplast extracts of maize.

Isolated chloroplasts are capable of synthesizing chloroplast DNA in the presence of Mg2+ and deoxynucleoside triphosphates. The in vitro reaction proceeds for at least 60 min and is inhibited by KC1 and N-ethylmaleimide. Stretches of several hundred nucleotides in length are synthesized within an hour. Little or no inhibition is shown by aphidicolin (an inhibitor of eukaryotic DNA polymerase alpha), dideoxythymidine triphosphate (an inhibitor of eukaryotic DNA polymerases beta and gamma), nalidixic acid, or rifampicin. Ethidium bromide is a moderate inhibitor of DNA synthesis in the isolated chloroplast. Soluble extracts of chloroplasts will copy exogenously added recombinant plasmid circular DNA containing fragments of chloroplast DNA, and this reaction is strongly inhibited by ethidium bromide. Copying of the plasmid DNA takes place on the relaxed circular or linear forms of the DNA, but no specific initiation sites on the chloroplasts' DNA fragments of the recombinant plasmids have been detected. Our data are consistent with a repair mechanism operating in vitro but may also represent incomplete replicative DNA synthesis.

Aphidicolin↗
PubMed1982

The effects of hyperbaric oxygen on experimental noise damage to the ears.

The effect of hyperbaric oxygen on cochlear microphonics, action potential of the auditory nerve, and brain stem response damaged by short exposure to noise is varied. Of 26 guinea pigs 14 showed a positive influence as measured by amplitudes. In 12 animals oxygen had little or no effect. The reason for this could lie in the individual reaction to the anesthetic of the section of the auditory nerve tested. The reaction of postmortem cochlear microphonics after hyperbaric oxygen treatment indicates oxygen diffusion through the round window.

Animals↗
PubMed1982

[Diagnostic value of sigmoidoscopic examination in diseases of the colon (author's transl)].

215 Cases out of 400 colosopic and 300 sigmoidoscopic examinations showed polypi and carcinomas. The polypi of 170 patients were located at a rate of 63,5% in the rectum and sigma area and of 36,5% in the proximal colon sections. Out of 45 carcinomas 80% could be localized in the rectum and sigma area and 20% in the further parts of the colon. Patients, if only sigmoidoscopically examined, showed polypi at a rate of 4,7% and carcinomas of 1,3%. For patients coloscopically examined polypi were found at a rate of 23,5% and carcinomas of 8% in the rectum and sigma area. 66% of all polypous changes and 82% of carcinomas were found with patients beyond 60 years of age. In 17 cases colitis ulcerosa, in 3 cases Morbus Crohn and in 3 cases of lipom could be established. The relatively high rate of pathological abnormities found in the upper colon section proves the diagnostic value of a total coloscopic examination. The recto-sigmoidoscopic examination therefore should be restricted to provisionary tests only.

Adult↗