Biomedical subjects

K Alef

Publications and source records attributed to K Alef.

6 recordsLinked to original sources

PubMed1996

[Influence of physiological and pharmacological amounts of iodine on the 131I uptake of the thyroid gland--a model calculation].

AIM: The aim of this paper was to use a iodine metabolism model in order to analyze theoretically the different aspects of the iodine metabolism. METHOD: To perform this a three compartment model was developed. RESULTS: With this model we examined the influence of physiological and pharmacological iodine amounts on the iodine-131 uptake in the thyroid gland and additionally the excretion of Iodine-131 after radiotherapy. It can be said, that an in-patient admission for a duration of at least three days to perform a radiotherapy is sensible (wise) and a iodine-poor diet prior to the radiotherapy is of advantage. Regarding the iodine blockade of the thyroid gland after a reactor accident the effects (outcome) of the German recommendations were compared with the WHO-guidelines. CONCLUSION: The model of iodine metabolism is suited for analyses even if because of ethic or other limitations measurements at human beings are not possible.

Germany↗

PubMed1983

Uptake of methionine sulfoximine by some N2 fixing bacteria, and its effect on ammonium transport.

The N2 fixing bacteria Klebsiella pneumoniae, Azospirillum brasilense, Rhodopseudomonas sphaeroides and Rhodospirillum rubrum, but not Azotobacter vinelandii accumulate the glutamine analogue methionine sulfoximine in the cell. In the accumulating cells methionine sulfoximine inhibits ammonium transport. Accumulation and inhibition are prevented by glutamine.

Ammonia↗

PubMedDate not supplied

Clostridium difficile-associated disease. Implications for midwifery practice.

Clostridium difficile-associated disease (CDAD), a gastrointestinal infection with a wide range of manifestations whose primary symptom is diarrhea, occurs when antibiotic medications, or rarely other drugs or conditions, disrupt the normal colonic microflora, making it susceptible to the growth of toxigenic C difficile. It is a significant nosocomial infection and an increased incidence has been noted in recent years. Although infrequently seen in midwifery practices, it does occur and may increase with the growing usage of intrapartal antibiotics. Midwives may evaluate and treat a client with an initial episode of mild to moderate CDAD; they also may manage collaboratively or refer for medical management those clients with recurrent or severe disease. This article reviews the epidemiology, pathogenesis, clinical presentation, prevention, and midwifery management of initial and recurrent CDAD. The limitation in the use of oral vancomycin due to the emergence of vancomycin-resistant enterococcus, resulting in metronidazole becoming the primary agent for treatment of CDAD, and the implications of this in the treatment of CDAD during pregnancy and lactation are addressed.

Adult↗

PubMedDate not supplied

Characterization of a soluble NADH-independent nitrate reductase from the photosynthetic bacterium Rhodopseudomonas capsulata.

The assimilatory nitrate reductase was purified 60-fold from a newly isolated, nitrate assmilating strain of the photosynthetic bacterium Rhodopseudomonas capsulata. The enzyme had a molecular weight of about 180 000 dalton and was typically prokaryotic in that it was not active with reduced pyridine nucleotides but rather with reduced flavins.

Flavin Mononucleotide↗

PubMedDate not supplied

Assimilatory nitrate reductase of Rhodopseudomonas capsulata AD2: a molybdo-hemeprotein.

The assimilatory nitrate reductase of the phototrophic bacterium Rhodopseudomonas capsulata strain AD2 was purified to homogeneity by a combination of ammonium sulfate fractionation, chromatography on DEAE-cellulose and isoelectric focusing (isoelectric point of 4.8). The purified enzyme was active only with reduced viologen dyes or reduced flavin as electron donors. Contrary to other bacterial assimilatory nitrate reductases, the enzyme was not inhibited by chlorate, but rather accepted this substance as an alternate substrate. The molecular weight of the enzyme was 185,000 dalton as determined by gelfiltration. Subunit analysis by sodium dodecyl sulfate (SDS) gel electrophoresis yielded a single protein band with a molecular weight of 85,000 dalton,, suggesting that the enzyme was composed of two identical subunits. The nitrate reductase contained 0.8 g-atoms molybdenum per 1.85 x 10(5) g protein and exhibited absorption maxima at 418, 523 and 552 nm in the reduced state (dithionite as reductant). The nitrate reductase of Rps. capsulata AD2 is the first prokaryotic enzyme of the assimilatory type that has been shown to contain heme.

Hemeproteins↗

PubMedDate not supplied

Molecular characterization of glutamine synthetase from the nitrogen-fixing phototrophic bacterium Rhodopseudomonas palustris.

The phototrophic bacterium Rhodopseudomonas palustris assimilated ammonium via glutamine synthetase and glutamate synthase. Diazotrophic and ammonium-grown cells had high levels of both enzymes, whereas enzymes of alternative assimilatory pathways were absent or had only low activities. Glutamine synthetase was purified to electrophoretic homogeneity within three steps by dye-ligand and ion exchange chromatography. Electron microscopy revealed a dodecameric molecular entity which was in accordance with parameters derived from electrophoretic techniques. The molecular weight of the enzyme monomer was 558000; that of the dodecamer 670000. The amino acid composition of R. palustris glutamine synthetase was determined and compared by a statistical method with other known enzyme compositions from prokaryotic and eukaryotic origins.

Amino Acids↗