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Biomedical subjects

R J Fischer

Publications and source records attributed to R J Fischer.

9 recordsLinked to original sources
PubMed1998

[Length of overseas research sojourn in the career path of academic surgeons].

Since there are no data concerning the results/efficiency of research stipends in foreign countries, the aim of this study was to analyze the experience of German surgeons doing research work abroad. Seventy-four fellows (residents) in surgical training who conducted research outside Germany between 1986 and 1995 have been interviewed using a detailed questionnaire. Back in Germany, the results and the experience gained from research abroad led in the majority of cases to a post doctoral degree, a high number of publications, as well as to intensified research efforts in the same field, using the methods learned abroad. Back home, the possibilities of pursuing research were often compromised by clinical workload. In general, better support for researchers in terms of better clinical and scientific perspectives is urgently needed, a demand that is voiced in numerous comments.

Career Choice↗
PubMed1996

Loupe microsurgical tubal sterilization reversal. Experience at a community-level naval hospital.

OBJECTIVE: To evaluate the success rates of loupe microsurgical tubal sterilization reversal procedures performed by a generalist obstetrician-gynecologist at a community-level naval hospital. STUDY DESIGN: Consecutive patients who underwent microsurgical tubal anastomosis under loupe magnification by the author during a 16-month period were subjected to a review for outcome in this case series report. RESULTS: Twenty-three patients who underwent reversal of tubal ligation by the author were examined for outcome. By 29 months after the last case studied, the overall conception rate was 78.3% and intrauterine pregnancy rate 68.6%. The miscarriage and ectopic rates were 13.0% and 8.7%, respectively. CONCLUSION: Loupe microsurgical tubal reversal by a properly trained generalist obstetrician-gynecologist at a community hospital rendered success rates comparable to those published in the literature.

Abortion, Spontaneous↗
PubMed1995

Solventogenic enzymes of Clostridium acetobutylicum: catalytic properties, genetic organization, and transcriptional regulation.

The enzymes acetoacetate decarboxylase and coenzyme A transferase catalyse acetone production from acetoacetyl-CoA in Clostridium acetobutylicum. The adc gene encoding the former enzyme is organized in a monocistronic operon, while the ctf genes form a common transcription unit with the gene (adhE) encoding a probable polyfunctional aldehyde/alcohol dehydrogenase. This genetic arrangement could reflect physiological requirements at the onset of solventogenesis. In addition to AdhE, two butanol dehydrogenase isozymes and a thiolase are involved in butanol synthesis. RNA analyses showed a sequential order of induction for the different butanol dehydrogenase genes, indicating an in vivo function of BdhI in low level butanol formation. The physiological roles of AdhE and BdhII most likely involve high level butanol formation, with AdhE being responsible for the onset of solventogenesis and BdhII ensuring continued butanol production. Addition of methyl viologen results in artificially induced butanol synthesis which seems to be mediated by a still unknown set of enzymes. Although the signal that triggers the shift to solventogenesis has not yet been elucidated, recent investigations suggest a possible function of DNA supercoiling as a transcriptional sensor of the respective environmental stimuli.

Base Sequence↗
PubMed1993

Cloning, sequencing, and molecular analysis of the sol operon of Clostridium acetobutylicum, a chromosomal locus involved in solventogenesis.

A DNA region of Clostridium acetobutylicum contiguous with the adc operon has been cloned and sequenced. Structural genes encoding the acetoacetyl coenzyme A:acetate/butyrate:coenzyme A transferase (ctfB and ctfA) and an alcohol/aldehyde dehydrogenase (adhE) could be identified. These three genes together with a small open reading frame (ORF) of unknown function (upstream of adhE) formed an operon (sol operon), as shown by mRNA analyses. The complete sol operon was transcriptionally induced or derepressed before the onset of solventogenesis, thus confirming earlier results of Northern hybridizations with a ctfB gene probe (U. Gerischer and P. Dürre, J. Bacteriol. 174:426-433, 1992). Upstream of the sol operon, we identified two putative promoters that were located in regions with possible stem-loop structures formed by several inverted repeats. The distal promoter P1 showed only minor transcription initiation in solventogenic C. acetobutylicum cells but was recognized in Escherichia coli, presumably because of its high similarity to the sigma 70 consensus sequence. The adhE-proximal promoter P2 directed the major transcription start point in solventogenic C. acetobutylicum but was not recognized in E. coli. The clostridial AdhE showed high similarity to a novel family (type III) of alcohol dehydrogenases. Two other ORFs (ORF 5 and ORF 6) were found on the cloned DNA region that showed no significant similarity to sequences in various available data bases. mRNA studies revealed that ORF 5 formed a monocistronic operon and showed increased expression before onset of solventogenesis.

Alcohol Dehydrogenase↗
PubMed1965

Rabbit 19S antibodies with allotypic specificities of the a-locus group.

Activity of bacteriophage T4 neutralizing antiserums obtained 8 days after a primary immunization of rabbits with purified phage T4 is due to antibodies of the 19S (IgM) type. This neutralizing activity could be partially inhibited by treatment with excess antiserum directed against the a-locus group allotypic specificity carried by the whole rabbit serum.

Animals↗