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Biomedical subjects

R J Fischer

Publications and source records attributed to R J Fischer.

13 recordsLinked to original sources
PubMed2005

[Is the Canadian CT head rule for minor head injury applicable for patients in Germany?].

PURPOSE: To evaluate the applicability of the Canadian CT Head Rule (CCHR) on head trauma patients in a German university hospital. METHODS: 122 patients (m = 74; f = 48; 40 +/- 19 years) were examined with cranial CT due to minor head trauma. The need for cranial CT according to the CCHR was evaluated retrospectively. RESULTS: With a sensitivity of 98.9 % and a specificity of 46.6 % all patients with the need for neurosurgical intervention were detected by applying the major criteria of the CCHR. Also, every patient with severe brain injury was detected by the extended criteria with a sensitivity of 99.6 % and a specificity of 34.1 %. This would have led to a reduction in the rate of cranial CT examinations by 45.1 % for the major and 22.1 % for the extended criteria. No patient with severe brain injury would have been missed by application of the criteria. CONCLUSION: The Canadian CT Head Rule for patients with minor head trauma is applicable with a very high sensitivity and the potential of significantly reducing the rate of cranial CT examinations in these patients.

Accidental Falls↗
PubMed2000

Identification of two genes encoding putative new members of the ECF subfamily of eubacterial RNA polymerase sigma factors in Clostridium acetobutylicum.

Two genes from Clostridium acetobutylicum DSM 792 were identified which are predicted to encode new members of the ECF subfamily of eubacterial RNA polymerase sigma factors. The sigX gene has the potential to encode a 184-amino acid protein with a molecular mass of 21,870 Da and with the highest overall similarity to Fecl of Escherichia coli (27 % identical residues). The second gene, which is predicted to encode an alternative sigma factor of the ECF subfamily, is the previously described orf2 gene (Gerischer and Dürre, 1990) located in the adc gene region of C. acetobutylicum. The deduced protein of orf2 has significant similarity to SigX of C. acetobutylicum (22 % identical residues) and shares structural features with other alternative sigma factors. Therefore, it is proposed to rename orf2 as sigY. Analysis of the phylogenetic relationship revealed that SigX from C. acetobutylicum, together with sigmaE from Streptomyces coelicolor and SigX from Bacillus subtilis, form a gram-positive cluster within the ECF subfamily and that SigY from C. acetobutylicum together with UviA from Clostridium perfringens, form a separate cluster located between the gram-positive cluster and the sporulation sigma factor sigmaH from B. subtilis.

Amino Acid Sequence↗
PubMed1999

[Foreign research position in the career development 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 were interviewed using a detailed questionnaire. Back in Germany, the results and experience gained from research abroad led in the majority of cases to a PhD degree ("habilitation"), a high number of publications, and intensified research efforts in the same field using the methods learned abroad. In Germany, better support for researchers in terms of better clinical and scientific perspectives is urgently needed according to numerous comments.

Adult↗
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↗
PubMed1994

A comparison of the CPAP performance characteristics of the Puritan-Bennett 7200a and a prototype continuous pressure-regulating ventilator.

BACKGROUND: A prototype demand-flow medical ventilator for intensive care unit (ICU) applications has been developed with the ability to maintain continuous pressure regulation of proximal airway pressure during both inspiratory and expiratory respiratory phases. The performance of this system was investigated in laboratory tests of continuous positive airway pressure (CPAP) mode, a ventilatory mode in which airway pressure regulation is strongly challenged. MATERIALS & METHODS: Comparative tests of the pressure-regulating ventilator (PRV) prototype and a Puritan-Bennett 7200a (PB7200a) ventilator were made in three performance categories: pressure-volume product error, peak pressure error during inspiration, and peak pressure error during expiration. Testing was performed on a Bio-Tek VT-2 test lung modified to simulate spontaneous breathing, at CPAP levels of 0, 10, and 20 cm H2O. Results were obtained at a lung compliance of 50 mL/cm H2O and at three parabolic airway resistance levels (Rp10, Rp20, and Rp50 cm H2O.L-2.s2 per ANSI Z79.7-1976). RESULTS: The PRV prototype achieved reductions in pressure-volume product error of more than 0.111 joules (43%) for all test conditions, relative to the PB7200a. Peak pressure errors were reduced by at least 4.0 cm H2O (55%) during inspiration and 4.9 cm H2O (38%) during expiration. CONCLUSIONS: An ICU ventilator utilizing continuous regulation of proximal airway pressure has been shown to provide statistically significant improvements in CPAP performance relative to the PB7200a in laboratory tests. Further testing will be required to quantify the clinical significance of these results.

Data Collection↗
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↗