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Biomedical subjects

J Weigelt

Publications and source records attributed to J Weigelt.

15 recordsLinked to original sources
PubMed2005

Periodontal status and preterm low birth weight: a case control study.

BACKGROUND: Previous studies have suggested that periodontal disease may be an important risk factor for preterm low birth weight. However, the link between periodontal health status of pregnant women and preterm low birth weight is contentious, as recent studies found no association between periodontitis and pregnancy outcome. OBJECTIVE: The aim of this study was to investigate this potential link in a German Caucasian population. METHODS: Fifty-nine pregnant women with a high risk for a preterm low birth weight infant (suffering from preterm contractions, cases, group 1) as well as 42 control women with no preterm contractions during pregnancy and having an infant appropriate for date and weight (>or= 37 weeks gestation, >or= 2500 g, group 2) were examined. Clinical periodontal status was recorded on a full mouth basis. Subgingival plaque samples were taken and periodontal pathogens were identified by polymerase chain reaction. Additionally, interleukin-1 beta level in gingival crevicular fluid was analysed. RESULTS: The mean percentage of sites showing moderate to advanced attachment loss (>or=3 mm) was low in all study groups (group 1: 9.9 +/- 11.2%; group 2:10.6 +/- 14.1%, respectively). No significant differences between the groups in any aspects of the studied periodontitis parameters could be detected. Using a logistic regression model controlling for known preterm low birth weight risk factors, no periodontitis-associated factors increased risk for preterm contractions or preterm low birth weight. The odds ratio (OR) was 1.19 for preterm contractions, the 95% confidence interval (CI) 0.46; 3.11 and 0.73 for preterm low birth weight; 95% CI: 0.13; 4.19, respectively. CONCLUSION: In this population, periodontitis was not a detectable risk factor for preterm low birth weight in pregnant women.

Adolescent↗
PubMed2001

NMR structure of the LCCL domain and implications for DFNA9 deafness disorder.

The LCCL domain is a recently discovered, conserved protein module named after its presence in Limulus factor C, cochlear protein Coch-5b2 and late gestation lung protein Lgl1. The LCCL domain plays a key role in the autosomal dominant human deafness disorder DFNA9. Here we report the nuclear magnetic resonance (NMR) structure of the LCCL domain from human Coch-5b2, where dominant mutations leading to DFNA9 deafness disorder have been identified. The fold is novel. Four of the five known DFNA9 mutations are shown to involve at least partially solvent-exposed residues. Except for the Trp91Arg mutant, expression of these four LCCL mutants resulted in misfolded proteins. These results suggest that Trp91 participates in the interaction with a binding partner. The unexpected sensitivity of the fold with respect to mutations of solvent-accessible residues might be attributed to interference with the folding pathway of this disulfide-containing domain.

Amino Acid Sequence↗
PubMed2001

Solution structure of the DNA binding domain of the human forkhead transcription factor AFX (FOXO4).

AFX is a human forkhead transcription factor. Based on results from studies of the orthologous transcription factor DAF-16 in Caenorhabditis elegans, it was suggested that some of the metabolic defects in both type I and type II diabetes may be due to unregulated activity of AFX. In the present study, we report the high-resolution NMR solution structure of the DNA binding domain of AFX. It is the first structure of the DNA binding domain from a small subfamily of forkhead transcription factors (i.e., AFX, FKHR, FKHRL1, FKHRL1P1, and FKHRP1). Despite rather low sequence identity for a protein within the forkhead family, the structure is remarkably similar to those of the DNA binding domains of HNF3-gamma and FREAC-11, and to a lesser extent the DNA binding domain of Genesis which displays a slightly altered orientation of the DNA recognition helix. The high degree of structural similarity between the DNA binding domains of different forkhead transcription factors implies that the repositioning of helix 3, observed for Genesis, cannot be a general feature for modulation of the DNA binding specificity. Other mechanisms that could influence the DNA binding specificity are discussed.

Amino Acid Motifs↗
PubMed1999

NMR structure of the N-terminal domain of E. coli DnaB helicase: implications for structure rearrangements in the helicase hexamer.

BACKGROUND: DnaB is the primary replicative helicase in Escherichia coli. Native DnaB is a hexamer of identical subunits, each consisting of a larger C-terminal domain and a smaller N-terminal domain. Electron-microscopy data show hexamers with C6 or C3 symmetry, indicating large domain movements and reversible pairwise association. RESULTS: The three-dimensional structure of the N-terminal domain of E. coli DnaB was determined by nuclear magnetic resonance (NMR) spectroscopy. Structural similarity was found with the primary dimerisation domain of a topoisomerase, the gyrase A subunit from E. coli. A monomer-dimer equilibrium was observed for the isolated N-terminal domain of DnaB. A dimer model with C2 symmetry was derived from intermolecular nuclear Overhauser effects, which is consistent with all available NMR data. CONCLUSIONS: The monomer-dimer equilibrium observed for the N-terminal domain of DnaB is likely to be of functional significance for helicase activity, by participating in the switch between C6 and C3 symmetry of the helicase hexamer.

Amino Acid Sequence↗
PubMed1998

DAFS experiments with non-centrosymmetric single crystals.

Diffraction anomalous fine structure (DAFS) experiments were applied to an epitaxially grown (Ga,In)P layer on a [001] GaAs substrate as a single-crystalline model substance. The requirements for the reliable measurement of reflection intensities as a function of photon energy, as well as the quantitative DAFS analysis resulting in the complex-valued fine-structure function of the scattering factor, are described. In the case of single crystals, effort had to be put into performing the DAFS measurements in order to hold the position of the Bragg reflection exactly during the energy scan. Using the zinc-blende-type structure as an example, it is shown for the first time that, similar to single-crystal structure analysis, the lack of inversion symmetry has a significant impact on the DAFS signal, so that DAFS may contribute to structure analysis as well.

Journal Article↗
PubMed1998

Opinions of practicing general surgeons on surgical education.

BACKGROUND: Collective opinions of practicing general surgeons on the current state of general surgical resident education are unknown. METHODS: A 26-item survey was mailed to practicing general surgeons in Minnesota and Texas. Average scores on 17 Likert-formatted questions and opinions on multiple-choice questions were compared by geographic area and academic affiliation. RESULTS: Overall response was 954 of 1,745 (55%). All surgeons felt changes were needed in surgical education. There was agreement by geographic area and academic affiliation that the current system of resident education allows chief residents to graduate with significant gaps in their education, and that the responsibility for correcting these gaps lies with the residency program. CONCLUSIONS: Opinions of general surgeons in two geographic areas and of differing academic affiliation regarding surgical education showed marked similarity. These data suggest change in the process of surgical education is the responsibility of the residency program and should be a priority for the profession.

General Surgery↗
PubMed1998

Spin-state selection filters for the measurement of heteronuclear one-bond coupling constants.

Novel alpha/beta-half-filter elements are proposed for the separation of the high-field and low-field component of 1JHC and 1JHN splittings into different subspectra. The alpha/beta-half-filter elements are of the same duration as the S3CT pulse sequence element and, like this, are less sensitive to cross talk between different subspectra than the original shorter alpha/beta-half-filters. The filter elements are demonstrated with the measurement of 1JHC coupling constants of C alpha H groups in 2D and 3D experiments and the subspectral editing of the four different multiplet components observed in two-dimensional alpha/beta-HSQC-alpha/beta spectra recorded without heteronuclear decoupling in either dimension.

Carbon Isotopes↗
PubMed1997

Precise limits of the N-terminal domain of DnaB helicase determined by NMR spectroscopy.

Two separate N-terminal fragments of the 470-amino-acid Escherichia coli DnaB helicase, comprising residues 1-142 and 1-161, were expressed in E. coli. The proteins were extracted in a soluble fraction, purified, and characterised physically. In contrast to the full-length protein, which is hexameric, both fragments exist as monomers in solution, as demonstrated by sedimentation equilibrium measurements. CD spectroscopy was used to confirm that the 161-residue fragment is highly structured (mostly alpha-helical) and undergoes reversible thermal denaturation. The structurally well-defined core of the N-terminal domain of the DnaB helicase is composed of residues 24 to 136, as determined by assignment of resonances from flexible residues in NMR spectra. The 1H NMR signals of the flexible residues are located at random coil chemical shifts, and their linewidths are significantly narrower than those of the structured core, indicating complete disorder and increased mobility on the nanosecond time scale. The results support the idea of a flexible hinge region between the N- and C-terminal domains of the native hexameric DnaB protein.

Bacterial Proteins↗
PubMed1992

Results of a multi-institutional outcome assessment: results of a structured peer review of TRISS-designated unexpected outcomes.

The utility of TRISS as a component of trauma center quality assurance (QA) was evaluated. TRISS survival probabilities were estimated for a total of 2,023 consecutive trauma patients admitted to three level-I trauma centers during a 6-month period. A structured peer review was performed of the 50 patients (2.1%) having statistically unexpected outcomes. For 23 (18 survivors, five deaths) TRISS-designated outcomes were sustained in peer review. In 27 cases (one survivor, 26 deaths) TRISS-designated outcomes were not sustained by peer review and TRISS. Limitations were identified in each case. Peer review of unexpected outcomes identified by TRISS provided a consistent and objective QA methodology. An understanding of TRISS as an objective component of the trauma center QA process is essential in blending it with what is, at present, a largely subjective process in many hospitals. Use of TRISS standardizes the peer review process, resulting in a more reliable base for development and improvement of trauma center QA programs.

Adolescent↗
PubMed1989

Early versus delayed stabilization of femoral fractures. A prospective randomized study.

A prospective randomized study comparing the results of early with delayed reduction and stabilization of acute femoral fractures in adults was performed over a two-year period in 178 patients. Only patients who were more than sixty-five years old and had a fracture of the hip were excluded. Arterial blood gases, injury-severity score at the time of admission, pulmonary function, days in the hospital, days in the intensive-care unit, and hospital costs were recorded for all patients. The patients were divided into two groups: those who had an isolated fracture of the femur and those who had multiple injuries. When stabilization of the fracture was delayed in the patients who had multiple injuries, the incidence of pulmonary complications (adult respiratory-distress syndrome, fat embolism, and pneumonia) was higher, the hospital stay was longer, and the number of days in the intensive-care unit was increased. The cost of hospital care showed a statistically significant increase for all patients who had delayed treatment of the fracture compared with those who had early stabilization.

Adolescent↗
PubMed1978

Evaluation of ultrasound in the diagnosis of acute and chronic biliary tract disease.

Oral cholecystography and intravenous cholangiography are the two studies most frequently used to confirm the diagnosis of biliary tract disease. Since it is not always practical to obtain these in acutely ill patients, gray scale sonography was evaluated to determine its accuracy. One hundred eight patients had sonography performed prior to operation. The sonogram was correct in 96 of the 108 patients (89%). There were four false-negatives (3.7%), one false-positive (0.9%), and seven patients (6.4%) in whom the study was nondiagnostic. Stones were seen in 88 patients and confirmed in 87 patients for an accuracy of 98.9% Sonography is a simple, noninvasive procedure by which cholelithiasis can be accurately detected. Because of the high correlation between sonography and operative findings, we suggest that cholecystosonography be used as the initial screening study in patients suspected of having biliary tract disease.

Acute Disease↗