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Biomedical subjects

R Binder

Publications and source records attributed to R Binder.

At least 73 records · Page 4Linked to original sources
PubMed1989

Predicted structures of apolipoprotein II mRNA constrained by nuclease and dimethyl sulfate reactivity: stable secondary structures occur predominantly in local domains via intraexonic base pairing.

Analyses of apolipoprotein II mRNA with chemical and enzymatic probes showed that double- and single-stranded regions were distributed uniformly along the mRNA except for a large (72 nucleotides) single-stranded region containing the translation stop codon. Secondary structure models constrained by the experimental data were made by varying the distance (along the mRNA) over which base pairing was allowed. Four prominent secondary structures were seen with restrictions of 165, 330, or 659 nucleotides suggesting that such structures from via local interactions over distances of 50-120 nucleotides. Predicted long range interactions involve only 2-3 base pairs while local interactions involve helices of 4-10 base pairs. Predicted helices of greater than or equal to 4 base pairs occur primarily within exons, raising the possibility that prominent secondary structures in mRNAs may be largely due to intraexonic base pairing. Tests of single- and double-stranded domains by oligonucleotide-directed RNase H cleavage and primer extension were in accord with the structure model and with nuclease and chemical modification data. The model predicting base pairing between the coding and the 3' noncoding regions was tested by RNase H cleavage followed by oligo(dT)-cellulose chromatography to separate 5' and 3' mRNA fragments. Most (82%) of the 5' fragment remained associated with the 3' noncoding region in a structure with a tm = 50 degrees C in 0.2 M Na+ suggesting that this stem could be stable in vivo. This stem may be stable in the isolated mRNA, but would likely occur transiently in polyribosomal apolipoprotein II mRNA due to ribosome transit through the 5' side of the stem. Alternate structures may occur in this region during ribosome transit and play a role in translation termination or in determining the susceptibility of the mRNA to degradation.

Animals↗
PubMed1987

Neuroleptic dose: a statistical model for analyzing historical trends.

Neuroleptic dosing practices during inpatient treatment of schizophrenia were examined for 1490 admission episodes during 1973 through to 1982 in two wards of a university hospital. Chlorpromazine-equivalent dose levels (CPZE) declined 50% between 1974 and 1980. As expected, length of treatment and choice of drug were both strongly related to CPZE. The general drop in CPZE is not explained by shorter treatment and changing choice of drug, however. Oral fluphenazine, haloperidol, and depot fluphenazine are used to higher maximum levels than chlorpromazine and other neuroleptics, when maximum dose is reached after one week or longer. The results illustrate that by seeking an appropriate statistical model, aggregate trends in dosing practices can be described while avoiding several of the shortcomings of earlier surveys of hospital practice.

Antipsychotic Agents↗
PubMed1986

[Determination of trimethoquinol in plasma by electrochemical detection after HPLC separation].

A high pressure liquid chromatographic method with internal analogue standardization for the determination of trimethoquinol (1-1-(3,4,5-trimethoxybenzyl)-6,7-dihydroxy-1,2,3,4-tetrahydroisoq uinoline hydrochloride) in plasma is described. The method comprises extraction from plasma at pH 9 with ethyl acetate, back-extraction into phosphoric acid and quantification after HPLC separation using a reverse phase by means of electrochemical (reductive) detection after electrochemical preoxidation. When using 5 ml plasma the lower limit of detection is 40 pg/ml. Under routine conditions the limit of determination is determined to be 0.1 ng/ml. The variation coefficients drop from about 7% in the low range to about 4% at 5 ng/ml. The determination of trimethoquinol is not impaired by its monomethylated metabolites.

Acetates↗
PubMed1985

Serum antielastase and neutrophil elastase levels in PiM phenotype cigarette smokers with airflow obstruction.

In order to assess blood factors which might explain why some cigarette smokers develop airflow obstruction while others do not, we compared two groups of PiM phenotype volunteers matched for age, sex and total pack-years of cigarette smoking; one group had airflow obstruction and the other did not. Functional levels of alpha-2-macroglobulin (alpha-2-M) and alpha-1-protease inhibitor (alpha-1-PI) were separately assessed by a protease binding procedure. Neutrophils were isolated from blood by counterflow centrifugation, and their elastase content was assayed with 3H-elastin-SDS (sodium dodecyl sulfate). The obstructed and nonobstructed groups were not different with respect to functional or immunoreactive levels of alpha-1-PI and alpha-2-M or elastase levels in their neutrophils. We do not find imbalances of circulating elastase or antielastase levels in PiM phenotype smokers with airflow obstruction.

Adult↗
PubMed1984

[Blood lead content in the Viennese population (1982)].

The lead content of blood was determined in 213 cases of sudden death (accident victims) in the population of Vienna. The determinations were carried out by atomic absorption spectrometry (graphite furnace), similarly as in the case of the previous investigation in 1972. The mean value was now 242 micrograms/l, as compared with 261 micrograms/l in 1972. The difference was not statistically significant.

Austria↗
PubMed1984

Identification and characterization of neutrophil chemotactic activity in aspirin-induced asthma.

In order to determine if mast cell mediators are released during aspirin challenge in aspirin-sensitive asthmatics, we measured neutrophil chemotactic activity, which has been shown to be an indicator of mast cell degranulation. Four aspirin-sensitive asthmatic subjects were given doses of aspirin (60 to 325 mg) previously determined to cause a 20 to 30% fall in forced expiratory volume in one second (FEV1); pulmonary function was followed by serial spirograms and body plethysmography. Serum was obtained before and at 30, 60, 90, 120, 180, and 240 min after challenge, corresponding to the times of pulmonary function measurements. Neutrophil chemotactic activity was measured using a modified Boyden chamber assay. Maximal bronchoconstriction occurred 60 to 120 min after aspirin ingestion. An increase in neutrophil chemotactic activity of 300 to 600% over baseline was detected in all subjects. In 3 subjects, neutrophil chemotactic activity release paralleled bronchoconstriction, and in 1 subject, it followed onset of bronchoconstriction. Physicochemical analysis showed that the neutrophil chemotactic activity eluted in the void volume of a Sephadex G-200 column (greater than or equal to 250,000 daltons) and from Sephadex QAE anion exchange chromatography in a region corresponding to 0.2 to 0.3 M NaCl. Its isoelectric point was in the pH range 6.5 to 7.5. These characteristics are compatible with neutrophil chemotactic factor of mast cell origin. Pretreatment with sodium cromolyn (40 mg) completely eliminated neutrophil chemotactic factor release, but only partially suppressed the fall in FEV1 in 2 subjects and had no effect on FEV1 fall in a third.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1982

Purification and properties of the pyruvate dehydrogenase complex from Salmonella typhimurium and formation of hybrids with the enzyme complex from Escherichia coli.

The pyruvate dehydrogenase (Pyruvate:lipoamide oxidoreductase (decarboxylating and acceptor acetylating), EC 1.2.4.1) complex from Salmonella typhimurium was purified, characterized and compared to the enzyme complex from Escherichia coli. No difference could be found in the molecular weights of the native enzyme complexes or in the single polypeptide chains of the enzymes of the two organisms. Values of 100 000, 87 000 and 56 000 were obtained for the polypeptide chains of the pyruvate dehydrogenase, the dihydrolipoamide transacetylase (acetyl-CoA:dihydrolipoamide S-acetyltransferase, EC 2.3.1.12) and the dihydrolipoamide dehydrogenase (NADH:lipoamide oxidoreductase, EC 1.6.4.3) components, respectively. Complete cross-reactivity was found with antibodies directed against the pyruvate dehydrogenase complex from E. coli and electron micrographs of both enzyme complexes reveal identical structures. A high Michaelis constant for pyruvate with a Km = 6 . 10(-4) M and a somewhat weaker cooperativity as compared to the enzyme from E. coli reflect some minor differences, while the binding of the cofactor thiamine diphosphate (Km = 1 . 10(-6) M) is identical for both enzyme complexes. Reassociation to a fully active complex molecule works with equal facility between the pyruvate dehydrogenase component and a dihydrolipoamide transacetylase: dihydrolipoamide dehydrogenase subcomplex from either organism in all possible combinations.

Acetyltransferases↗
PubMed1981

Pyruvate dehydrogenase component of the pyruvate dehydrogenase complex from Escherichia coli K12. Purification and characterization.

Free pyruvate dehydrogenase component of the Escherichia coli K12 pyruvate dehydrogenase complex was isolated from a mutant lacking the dihydrolipoamide transacetylase component. The procedure, employing three chromatographic steps, yields a product that is electrophoretically pure. The purified enzyme reassociates with the residual complex lacking this component to a fully active enzyme complex. The kinetic characteristics of the free component were compared to that of the enzyme integrated into the native complex molecule. No essential differences could be detected regarding the behaviour of the catalytic reaction with variations in temperature, pH and substrate concentration. An inhibition, competitive to pyruvate, of the pyruvate dehydrogenase component (Ki = 18 microM) by fluoropyruvate was observed with both enzyme forms. Pyruvate exerts a cooperative effect both upon the partial enzyme reaction of the pyruvate dehydrogenase component as well as upon the overall reaction of the native enzyme complex. However, there is a clear difference in the shape of the saturation curves of both types of reaction. Experiments with the free enzyme, with the component integrated into the native complex molecule and with enzyme complexes which are partially deficient in the pyruvate dehydrogenase component demonstrate that the type of saturation curves obtained were characteristic for the reaction observed rather than for the interaction of a high number of subunits of the pyruvate dehydrogenase complex.

Escherichia coli↗
PubMed1979

Malpractice--in dermatology.

Among twenty-three types of physicians, dermatologists rate sixth lowest in malpractice risk. With dermatology, the risk of a suit is general; no one doctor or type of dermatologic practice has been shown to bear unusual risk--everyone is susceptible. However, dermatologist who give x-ray therapy or limit their work to cosmetic procedures rate higher. Patients sue because of facial burns or scars, negligent diagnosis, drug reaction, falls in the office, wart removal, and treatment that exceeds the patient's desire at the moment. Care must be exercised in the use of problem drugs such as antineoplastic agents, corticosteroids, oral contraceptives, sulfones, vitamin A acid, liquid nitrogen, cantharidin, podophyllin, and fluorescent dyes. Dermatologists are urged to obtain consultation for the benefit of patient and doctor, to maintain good relations with fellow physicians, and to avoid inappropriate criticism of other physicians. Lengthy lists of "do's" and "don'ts" in patient care are included, and some possible changes in the malpractice situation are listed.

California↗
PubMed1978

[The implication of trace metals in household products in the causation of contact dermatitis (author's transl)].

The 6 most common fluid and powder detergent brands in use in Austria were analyzed as to their nickel and chromium content. The analysis was carried out by means of atomic absorption spectroscopy. 1. The above-mentioned metals were found to be present in each of the products analysed. On average, the fluid detergents contained ten times less nickel and chromium than the powders. 2. Repeated investigations revealed a considerable variation in metal ion content in different batches of the same detergent. Thus, presumably the raw products already contain nickel and chromium and it is unlikely that these ions get into the products during the manufacturing process. 3. In the appropriately diluted detergent powder solutions, as recommended by the producer, the content of nickel was found to lie between 0.4 ppm and 0.717 ppm and the chromium content ranged from 0.733 to 0.917 ppm. Since powder detergents also contain complex-producing agents, it can be assumed that these concentrations of metal ions do not suffice for sensitization. In the fluid detergents the nickel and chromium contents were found to be below the safety limit for the elicitation of an excematous reaction.

Allergens↗
PubMed1976

[The umbilical cord blood lead concentration: a comparison between an urban and rural population (author's transl)].

The cord blood lead level was determined to 40 newborn infants. The values were significantly higher in the infants born to mothers resident in Vienna than in the infants born to the group of mothers from the rural surroundings of Eisenstadt. The overall mean blood level was 17.7+/-7.4 mug/100 g. Increasing pollution requires investigations concerning possible effects on the growing fetus and would serve as foundation for future trend assessment studies.

Air Pollution↗
PubMed1976

[Rat jejunal xylose and galactose absorption dependent on the intestinal bacterial flora and after cytostatics administration].

The influence of the bacterial flora of the intestine and of cytostatic drugs on the intestinal xylose and glucose absorption in the rat is studied by a perfusion technique in vivo. Conventional, germfree and decontaminated animals show no different xylose absorption rates while the galactose absorption is decreased in germfree and decontaminated animals compared to conventional rats. Three days after a single injection of cytostatic drugs the xylose absorption is diminished in conventional and decontaminated animals compared to untreated rats. In germfree rats no effect of cytostatics on the xylose absorption can be proved. The galactose absorption is unchanged after cytostatics in conventional and decontaminated animals, but increased in germfree rats.

Animals↗