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W Renner

Publications and source records attributed to W Renner.

48 records · Page 3Linked to original sources
PubMed1987

Tubulin oligomers and microtubule assembly studied by time-resolved X-ray scattering: separation of prenucleation and nucleation events.

This paper describes a time-resolved X-ray scattering study of microtubule assembly by synchrotron radiation. The method is complementary to light scattering but allows a better distinction between oligomeric and polymeric assembly states. With an improved rapid temperature jump device, it is shown that temperature-induced microtubule assembly is preceded by prenucleation and nucleation events involving oligomers of tubulin, in analogy with earlier results from near-equilibrium temperature scans. In general, the two phases closely overlap, but in certain conditions they can be observed separately. The prenucleation events seen by X-rays can be described as a rapid temperature-dependent equilibrium, with ring oligomers dissociating into smaller oligomers and subunits at elevated temperature. Different solution conditions affect mainly the time lag between the prenucleation and nucleation phases; this in turn determines the apparent magnitude of the prenucleation steps. By contrast, the temperature dependence of the equilibrium between the prenucleation oligomers shows little influence on solution conditions. The results suggest that the ring-forming and tubule-forming assembly modes of tubulin are governed by different interactions between subunits, although they may be based on a pool of similar intermediates.

Hydrogen-Ion Concentration↗
PubMed1983

Fetal sex determination by ultrasound scan in the second and third trimesters.

Sector real-time ultrasound examinations of the fetal perineal area were done on fetuses ranging in age from 14 weeks to term. An attempt was made to determine fetal sex in 404 consecutive cases. Seventeen cases were lost to follow-up and 20 fetuses under 16 weeks of age were omitted, as only two predictions were made in this group. The fetal sex was predicted in 266 of the remaining 367 fetuses with 93% accuracy. In this series, 194 fetuses were less than 24 weeks of age; within this group, 118 predictions were made with an accuracy rate of 86%.

Female↗
PubMed1980

Corticosteroids in acute myocardial infarction.

Forty-two patients admitted to the Coronary Care Unit with a diagnosis of acute myocardial infarction were studied within 24 hours of the onset of symptoms. In addition to therapy determined by the attending physician, there was a double-blinded administration of either a placebo or methylprednisolone, 30 mg/kg intravenously every 6 hours for four doses. This drug had no beneficial effect on infarct size, dysrhythmias, complications, or left ventricular function 2 weeks after infarction.

Creatine Kinase↗
PubMedDate not supplied

Simultaneous in vivo quantitation of vascular endothelial growth factor mRNA splice variants.

Vascular endothelial growth factor (VEGF) is an important regulator of angiogenesis. In vivo expression of four different VEGF isoforms, consisting of 121, 165, 189 or 206 amino acids, has been found in the human organism, with all isoforms arising from a single gene by alternative mRNA splicing. We developed an assay for simultaneous quantitation of VEGF isoform expression using competitive polymerase chain reaction (PCR). RNA was isolated from cells, reverse transcribed to cDNA and coamplified with a synthetical competitor DNA using VEGF specific primers. Amplification products were analyzed electrophoretically and concentration of VEGF transcripts calculated. Concentration of housekeeping gene glyceraldehyde-3-phosphate dehydrogenase (GAPDH) transcripts was quantitated as above, VEGF gene activity is presented as ratio VEGF mRNA to GAPDH mRNA. Using this assay, we were able to detect and quantitate in vivo expression of VEGF121, VEGF165 and VEGF189 by human peripheral blood mononuclear cells (PBMC). These are the first quantitative data of in vivo VEGF expression by PBMC, suggesting a role for them in the maintenance of the vasculature.

Adult↗
PubMedDate not supplied

A common 936 C/T mutation in the gene for vascular endothelial growth factor is associated with vascular endothelial growth factor plasma levels.

BACKGROUND: Vascular endothelial growth factor (VEGF) is an important regulator of angiogenesis. Strong interindividual variations of VEGF plasma levels have been reported previously. Aim of the present study was to search for mutations in the 3' untranslated region (3'-UTR) of the VEGF gene and to analyze their relation to VEGF plasma levels. METHODS: The complete 3'-UTR (nucleotide 700-2622) of the VEGF gene was screened for sequence variations by single-strand conformation polymorphism (SSCP) analysis. Frequencies of mutated alleles were determined in 119 healthy subjects; VEGF plasma levels were analyzed in a subgroup of 23 healthy men aged 18-36 years. RESULTS: Three novel mutations (702 C/T, 936 C/T, 1612 G/A) were found, allele frequencies of 702T, 936T and 1612A were of 0.017, 0.160 and 0.471, respectively. VEGF plasma levels were significantly lower in carriers of the 936T allele (9.1 +/- 2.7 pg/ml, mean +/- SEM) than in noncarriers (28.0 +/- 5.5 pg/ml, p = 0.033), whereas the 702 C/T and the 1612 G/A mutations showed no association with VEGF plasma levels. The 936 C/T exchange led to the loss of a potential binding site for transcription factor AP-4, although the functionality of this binding site remains unclear. CONCLUSION: We have found three common mutations in the VEGF gene; one of them, a 936 C/T exchange, may be an important determinant of VEGF plasma levels.

3' Untranslated Regions↗