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Biomedical subjects

U Seitz

Publications and source records attributed to U Seitz.

60 records · Page 4Linked to original sources

Capillary electrophoretic analysis of flavonoids.

Combining the effects of electrophoresis and electroendosmosis, flavonoids were separated in less than ten minutes in a fused silica capillary tube with a borate buffer adjusted to pH 10. An increase in the concentration of borate from 0.1 to 0.2 M resulted in longer migration times due to a decrease in electroosmotic flow, but also in improved selectivity and higher resolution of flavonoids. The calibration curve of rutin showed a detection limit of 0.02 mg/mL and linearity over its pharmaceutical concentration range. Using an internal standard of known concentration, the content of rutin in a methanolic extract of Sambuci flos could be determined with a coefficient of variation as small as 3.8% by the molar ratio-peak area ratio method.

Boric Acids↗

Biventricular pacing for successful weaning from extracorporal circulation in an infant with complex tetralogy of fallot.

Biventricular pacing therapy is an innovative therapy for improving cardiac output in adult patients with severe heart failure. However, this technique is not yet used in infants with congenital heart disease. We present a six month old infant with tetralogy of fallot and atresia of the left pulmonary artery in which biventricular stimulation led to improved left ventricular function and successful weaning from extracorporeal circulation.

Cardiac Output, Low↗

Cerebral gnathostomiasis as a cause of an extended intracranial bleeding.

This is a report of a fourteen year old Thai-girl who presented with acute hemiparesis because of intracranial haemorrhage six weeks after immigrating to Germany. Marked blood eosinophilia and raised IgE in serum in comparison with her origin led to the suspected diagnosis of parasitosis. Angiography showed mycotic aneurysm typical for cerebral gnathostomiasis one of the major causes of intracranial haemorrhage in children in Thailand. This diagnosis was confirmed by detecting specific antibodies against Gnathostoma spinigerum in serum and CSF by Western blot. Therapy was started with albendazole and dexamethasone and the girl made a complete recovery. In case of intracranial haemorrhage cerebral gnathostomiasis should be considered if the patient originates from an endemic area.

Acute Disease↗

Transport and processing of ribosomal RNA in plant cells after treatment with cycloheximide.

In freely suspended cells of parsley (Petroselinum crispum) protein synthesis is inhibited nearly totally by 5 mug/ml cycloheximide within 10 min. This very low dose has a slight effect on the rRNA synthesis too. During an incubation period of 60 min with [32P] orthophosphate in the presence of the inhibitor (5 mug/ml) at least 65-70% mature rRNA are synthesized compared with the control. After 120 min the synthesis is progressively reduced to 60-65%, and after 240 min to 30-40%. Cycloheximide causes a delay of the prn addition to the 2.3 X 10(6) daltons RNA, normally detectable in pulse experiments, two further precursor molecules do emerge which undernormal circumstances apparently are shortlived. Their molecular weights are 2.0 X 10(6) and 0.9 X 10(6) daltons. The pulse-chase technique and cell fractionation into nuclear and ribosomal parts enables us to demonstrate a rapid transfer of labelled 18S and 25S RNA during a 15 min chase treatment to the mature cytoplasmic ribosomes. Under these conditions no differential transport of the two components takes place. The cells possess a pool of proteins. Therefore the formation of RNP-particles or ribosomes respectively and the transport from the nucleus to the cytoplasm are indipendent from protein synthesis for some time.

Biological Transport, Active↗

The molecular weight of rRNA precursor molecules and their processing in higher plant cells.

Actively dividing callus cells of higher plants (Petroselinum crispum, Daucus carota, Acer pseudoplatanus) were used to detect the primary gene product of rDNA in vivo. Parsley and carrot cells were labelled with [32P]orthophosphate. Under non-denaturing conditions, in both cases only one high molecular weight rRNA precursor was present on polyacrylamide gels. Its molecular weight did not exceed 2.5 x 10(6) dalton. Under denaturing conditions, 2.0--2.1 x 10(6) dalton were determined on formamide gels. This rRNA precursor was already present after a labelling period of 5--10 min. In parsley cells labelled mature rRNA (25S and 18S) arrived in the cytoplasm 45 min after onset of incubation. In Acer pseudoplatanus incubated with [3H]uridine two rapidly labelled components did emerge from polyacrylamide gels without formamide; their molecular weights were 2.3 and 3.2--3.4 x 10(6) dalton. After electrophoresis in formamide, the larger component disappeared, thus indicating that it would be an intermolecular aggregate of different RNAs. From these results we have no evidence for the existence of rRNA precursors exceeding the molecular weight of 2.5 x 10(6) dalton.

Cells, Cultured↗