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Biomedical subjects

R Studer

Publications and source records attributed to R Studer.

54 records · Page 3Linked to original sources
PubMed1978

Effects of calcium ionophores on the transport and distribution of calcium in isolated cells and in liver and kidney slices.

The effects of calcium ionophores on cellular calcium metabolism were studied in cultured kidney cells, in cells freshly isolated from rat kidney, and in liver and kidney slices. In isolated cells, these ionophores decreased the total cellular Ca content and the mitochondrial Ca. 45Ca efflux from prelabelled cells was also stimulated even in the absence of extracellular Ca. In slices, the ionphore A23187 increased the total slice Ca and the uptake of 45Ca. However, the mitochondria isolated from these slices treated with the ionophore had a lower total Ca and a depressed relative radioactivity. These results suggest that the increased cytosolic Ca produced by Ca ionophores may be due to mobilization of intracellular Ca stores rather than to a net shift of Ca from the extracellular fluids to the cell.

Animals↗
PubMedDate not supplied

Oligonucleotide fingerprinting with (CAC)5: nonradioactive in-gel hybridization and isolation of individual hypervariable loci.

The first topic to be treated in this paper is the nonradioactive DNA fingerprinting by means of in-gel hybridization with digoxigenated (CAC)5. Besides the fact that time-consuming Southern blotting can be avoided, the dried agarose is an excellent matrix to produce background-free nonradioactive DNA fingerprints. There is no tendency of either the oligonucleotide probe or the antibody towards unspecific binding to the dried agarose. Prehybridization and blocking steps are therefore superfluous. Furthermore, we will discuss what effect the degree of crosslinking of the antibody-enzyme conjugates has. The second topic concerns the isolation and characterization of locus-specific probes from a human (CAC)5 fingerprint. The isolation and characterization of one variable probe, by screening complete genomic libraries, is described and discussed. This probe is compared to a hypervariable single-copy probe, isolated from a size-enriched genomic library. The sequence of the repeat flanking locus-specific probe is presented and a semi-specific, adaptor-mediated polymerase chain reaction was designed to amplify (CAC)n/(GTG)n flanking sequences.

Base Sequence↗
PubMedDate not supplied

Highly instable (GATA)n-containing sequences of the mouse during the cloning process.

Mouse DNA fingerprints were obtained by HaeIII digestion of genomic DNA and in-gel hybridization with the (GATA)4 oligonucleotide probe. In order to obtain locus-specific probes that hybridize with only one fragment of the (GATA)4 DNA fingerprint, a genomic library of size-selected inserts was constructed using a system of direct subcloning from the phage clones. During the cloning procedure, the phage as well as the plasmid insert DNAs changed primarily within their repetitive DNA but also within adjacent nonrepetitive sequences, as was demonstrated for several clones by in-gel hybridization with the (GATA)4 probe as well as by sequence analysis. Isolated subclones varied within their (GATA)n repeats, resulting in different insert lengths. Several "metastable" as well as stable (GATA)4-positive subclones could be isolated. Also, vector sequences were affected by alterations during the cloning process. These phenomena are discussed within the context of possible mechanisms for cloning artifacts.

Animals↗
PubMedDate not supplied

Blood pressure overshoot under pentobarbitone anaesthesia following a single dose of clonidine in rats.

1. Withdrawal of chronic antihypertensive therapy with clonidine is known to produce a blood pressure overshoot. It has been reported that the same may occur after a single dose of clonidine. 2. A single, intramuscular dose of clonidine (0.05 mg/kg) produced an overshoot in blood pressure, on the day following administration, in normotensive rats anaesthetized with sodium pentobarbitone. 3. No rebound elevation of mean arterial pressure or of heart rate occurred in conscious, normotensive, spontaneously hypertensive or renal hypertensive rats following this dose of clonidine, nor did it occur in rats anaesthetized with ether. 4. It is suggested that the overshoot phenomenon in rats under barbiturate anaesthesia may involve an interaction between an effect of clonidine and the barbiturate.

Anesthesia, General↗