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Biomedical subjects

D Vetter

Publications and source records attributed to D Vetter.

At least 73 records · Page 4Linked to original sources
PubMed1985

In vitro recombination of bacteriophage T7 DNA: further characterization of the reaction using plasmid DNA.

We have used a plasmid which contains a cloned fragment of T7 DNA to study the properties of general recombination of phage T7 in vitro. It was shown that T7-infected cell extracts promote recombination by the exchange of double strands of DNA. While both products of these double-strand exchanges were detected, we were unable to show that they were formed during a single recombination event.

Cloning, Molecular↗
PubMed1985

[Hepatitis B virus, serological markers of viral infections and humoral immunity in alcoholic cirrhosis].

In order to define the role of hepatitis B virus (HBV) in alcoholic liver disease and to study the relationship between HBV and other common viruses, the serological markers of viral disease (HBV, Rubella, Polio, Herpes, and Cytomegalovirus-CMV) were compared in 163 patients with alcoholic cirrhosis (group C), 100 patients with alcoholic steatosis (group S) and in 168 non-alcoholic control subjects (group NA). A significantly increased prevalence of HBV markers in group C was related to the presence of anti-HBc antibodies, in 10.5 p. 100 of cirrhotic patients, vs. 1.2 p. 100 in group S and 1 p. 100 in group NA (p less than 0.01). In cirrhotic patients with HBV markers (HBV +) incidence of alcoholic hepatitis was 4 times lower and the total duration of alcohol overconsumption was significantly lower than in cirrhotic patients without these markers (HBV-). Hepatic function tests were not different in HBV + and HBV- cirrhotic patients, excepted for the ASAT/ALAT ratio (1.55 +/- 0.10 vs. 1.92 +/- 0.12; p less than 0.05). Prevalence of anti-CMV antibodies, and anti-herpes greater than 1/100 antibodies, was significantly increased in S and C groups (p less than 0.01). Anti-Rubella, Polio, and CMV antibody titers were higher (p less than 0.05) in HBV + than in HBV- cirrhotic patients. In cirrhotic subjects, titers of these 3 anti-virus antibodies were not related to alcoholic hepatitis or to IgG and IgM concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Viral↗
PubMed1985

[Prevalence of HLA-A and -B antigens, anti-HBc and -HBs antibodies in alcoholic hepatopathies].

The frequency of 26 HLA-A and B antigens and of antibodies to the hepatitis B core antigen (anti-HBc) and surface antigen (anti-HBs) has been studied in 150 alcoholic patients divided into 3 groups: I) n = 50, isolated hepatic steatosis; II) n = 50, acute alcoholic hepatitis +/- cirrhosis; III) n = 50, cirrhosis without acute alcoholic hepatitis. For the control group 184 blood donors were selected. In all these subjects, as in all the alcoholic patients, the Alsatian origin of four grand parents was proved. An increased frequency of HLA-B15 was observed in group III (34 p. 100) compared to the control group (9.8 p. 100) (corrected p less than 0.001). There was no significant difference between the four groups for all the other HLA antigens. In group III, the prevalence of anti-HBc and/or anti-HBs was higher in patients with HLA-B15 (64.7 p. 100) than in patients without this antigen (15.1 p. 100) (p less than 0.001). In groups I and II, there was no significant difference. These results suggest that there is a genetic predisposition to cirrhosis without acute alcoholic hepatitis, dependent on HLA-B15 antigen. This predisposition could involve the hepatitis B virus.

Acute Disease↗
PubMed1984

[Disturbances in glycoregulation and plasma amino acids in alcoholic hepatopathies. Study using the arginine test].

In order to investigate disturbances in glycoregulation and plasma amino acids and their possible relationship in alcoholic liver diseases, plasma concentrations of insulin, C-peptide, glucagon and branched-chain (valine, leucine, isoleucine) as well as aromatic (phenylalanine, tyrosine) amino acids were measured during an arginine test (i.v infusion of arginine chloride 0.5 g/kg over 30 min) in 21 alcoholic patients: 11 with cirrhosis (group C) and 10 with steatosis (group S). Insulin responses to arginine was reduced in both groups, whereas glucagon response was increased in group C and reduced in group S. Plasma concentrations of branched-chain amino acids were reduced in both groups, irrespective of the degree of hyperinsulinism. Plasma concentrations of aromatic amino acids were increased only in cirrhotic patients; the increase was independent of the degree of hyperglucagonism and of the plasma insulin/glucagon molar ratio. These results suggest that disturbances of glycoregulation in plasma amino acids imbalance do not play a major role in alcoholic cirrhosis and steatosis.

Adult↗
PubMed1983

Site-specific recombination of yeast 2-micron DNA in vitro.

Most strains of the yeast Saccharomyces cerevisiae harbor several copies of a 2-micron plasmid circle DNA termed "2 micron." This circular plasmid contains two 599-base-pair precise inverted repeats across which a site-specific inversion event occurs in vivo. This inversion is promoted by a plasmid-encoded function called "FLP." We have cloned the FLP gene of 2-micron DNA under control of a strong yeast promoter and transformed yeast cells with a plasmid containing the cloned FLP gene. Cell-free extracts from such a transformant promote highly efficient inversion of 2-micron DNA in vitro. The reaction requires a cation and works efficiently on supercoiled, relaxed circular, or linear DNA. The FLP activity bears certain similarities to the cre protein, a site-specific recombinase encoded by bacteriophage P1.

Base Sequence↗
PubMed1981

RNA splicing mutation in an aberrantly rearranged immunoglobulin lambda I gene.

The mouse cell line MOPC 315 is an IgA (lambda II)-producing myeloma. We have studied a derivative of MOPC 315 that secretes normal lambda II chains but no heavy chain. This derivative, MOPC 315-26, was found to contain a rearranged lambda I gene in addition to a rearranged lambda II gene. The rearranged lambda I gene was cloned into bacteriophage lambda DNA and its structure was studied. The lambda I gene was found to have arisen by an aberrant recombination event that resulted in a single base insertion at the site of V-J region joining. In addition, the gene contained numerous point mutations in the vicinity of the junction of the V and J regions. Two point mutations occurred in the donor splice sequence normally used for the removal of the intron between the J and C regions, suggesting that the RNA synthesized from the aberrantly rearranged lambda I gene would be unable to undergo proper RNA splicing.

Amino Acid Sequence↗
PubMed1977

Location of the ss--mutation of bacteriophage T7 in genes 10, the structural gene for the major capsid protein.

T7+ phage are unable to plate on a strain of Shigella sonnei D2 371-48. Spontaneous phage mutants arise (ss--mutants) that are able to plate on this strain of Shigella. We have shown by complementation studies and genetic crosses that the ss--mutation maps in gene 10, the structural gene for the major protein of the capsid. This finding implies that the gene 10 protein may interact with a host protein during phage development and that the abortive infection of T7 observed in S. sonnei D2 371-48 with T7+ phage may be a defect in head morphogenesis. Our studies also reveal that various T7 strains commonly contain deletions in nonessential regions. T7 ss--mutants selected after growth of T7+ on Shigella D2 371-48 often acquire a deletion in the 0.7 gene that is not necessary for the ss--phenotype. Finally, we have found a new nonessential region of the T7 chromosome that is located between 33 and 35.5% of the T7 genome length.

Capsid↗
PubMed1976

[Organization of mobile intensive care in Zurich].

A mobile intensive care unit (Kardiomobil) has been in operation in the Zurich area (600 000 inhabitants) since March 27, 1972. This unit is staffed by a doctor and a nurse experienced in coronary and intensive care and two ambulance drivers. Although primarily designed for pre-hospital coronary care, it is equipped and operated as a "mobile intensive care unit".

Arrhythmias, Cardiac↗
PubMed1976

Genetic recombination of bacteriophage T7 DNA in vitro.

We have demonstrated recombination of bacteriophage T7 DNA in vitro. An extract of Escherichia coli B cells infected with wild-type T7(T7+) is incubated with mature DNA extracted from T7 phage. Packaging of the exogenous DNA within the phage head appears to be preceded by recombination of exogenously added DNA with DNA present in the extracts. In order to detect the recombination, we used an exogenous DNA bearing a marker (ss-) such that progeny phage which have packaged this marker are able to plate on Shigella sonnei D2 571-48, whereas T7+ phage present in the extracts do not. The recombinational process bears many of the characteristics of in vivo recombination. The exogenous DNA is not packaged intact but undergoes fragmentation to a length of about 3000 base pairs before being incorporated into a mature DNA molecule. If ss- DNA bearing an amber mutation is used in the assay, the frequency of amber+ progeny produced varies with the distance of the amber marker from the ss- marker. When DNA bearing three mutations is used in the reaction, phage heterozygous for the unselected marker are readily detected. Finally the products of phage genes 4 (DNA replication protein), 5(DNA polymerase), and 6(exonuclease), genes previously implicated in recombination in vivo, are required for the in vitro reaction.

Coliphages↗
PubMed1976

Gastrointestinal involvement in systemic mastocytosis.

Four consecutive patients with systemic mastocytosis were studied. One patient had a malabsorption syndrome with only minor histological changes of the intestinal mucosa. Another patient with ulcer diathesis had a gastric secretory pattern resembling Zollinger-Ellison syndrome. Serum gastrin and histamine levels were consistently normal in all patients. Endoscopy of stomach and colon disclosed urticaria-like papulae either spontaneously or after topical provocation in all patients. No increase of mast cells was found in multiple mucosal biopsies. A markedly increased gastric tissue content of histamine was found, however, in the three patients studied. The findings suggest that urticaria-like lesions associated with a high tissue content of histamine may be more important that hyperhistaminaemia in causing the various gastrointestinal symptoms.

Adult↗
PubMed1974

Point mutants in the D2a region of bacteriophage T4 fail to induce T4 endonuclease IV.

We have studied the properties of presumptive point mutants in the D2a region of bacteriophage T4. Dominance tests showed that the D2a mutation was recessive to the wild-type allele. The mutations were shown to map in the D2a region by complementation against rII deletions. The D2a mutations were also located between gene 52 and rIIB by two- and three-factor crosses. The mutants are located at at least two distinct loci in the D2a region. The point mutants grow normally on all hosts tested and none of the mutants makes T4 endonuclease IV. We propose the name "denB" for the D2a locus.

Coliphages↗