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Biomedical subjects

A Lund

Publications and source records attributed to A Lund.

At least 109 records · Page 6Linked to original sources
PubMed1980

Free radical formation in gamma-irradiated 5-nitro-6-hydroxythymine at 77K: an electron spin resonance single crystal investigation.

An electron spin resonance single crystal investigation of gamma-irradiated 5-nitro-6-hydroxythymine has been carried out at 77K. The primary reduced species was identified and was shown to have the unpaired electron localized on the nitro group. NO2 radicals were identified and suggested to be formed in the decay of the primary oxidation product. A third radical which shows isotropic coupling to the methyl group was identified and is suggested to be formed by the homolytic cleavage of the C-NO2 bond. A mechanism for the radical formation is proposed.

Cold Temperature↗
PubMed1980

Yeasts in the rumen contents of musk oxen.

The yeast flora of 16 samples of rumen contents of musk oxen (ovibos moschatus) from East Greenland was examined. Variable numbers of yeast colonies developed on agar plates incubated at 25 degrees C, the counts being up to 136000 per g (wet wt). Of the 41 strains isolated, the majority belonged to Candida and Cryptococcus; others were species of Trichosporon, Rhodotorula, Torulopsis and Pichia. Very few colonies appeared on plates incubated at 37 degrees C, and only one species of Candida was isolated. Samples of rumen contents kept at about 5 degrees C for about 3 years contained a much greater number of yeasts, up to several million per g (wet wt) being counted on agar plates incubated at 25, 15 and 5 degrees C. The 30 strains isolated were of only three species of Candida, and none were obligate psychrophils.

Animals↗
PubMed1980

The distribution of chlorpromazine between plasma and erythrocytes.

Chlorpromazine is found to be taken up by the erythrocytes in a dissociable binding similar to that of the plasma protein binding so that an equilibrium is attained between these binding sites. The plasma/cell ratio is on an average 2 but is subject to large interindividual variations. This ratio is only moderately influenced by the presence of other drugs and anticoagulants in the blood. The consequences of the cell binding of drugs for the analytical result when using plasma or whole blood and the evaluation of blood concentrations of their relation to the therapeutic effect are discussed.

Anticoagulants↗
PubMed1979

Development and validation of a specific radioimmunoassay for somatostatin in human plasma.

Little is known about the factors controlling somatostatin secretion in man, and data are not available on the changes in circulating levels in various human physiological or pathophysiological states. This is mainly a consequence of the technical difficulties involved in measuring somatostatin in plasma. In the presence of plasma, binding of somatostatin tracer to antibody was consistently decreased by about 20%, and this could not be abolished by the addition of EDTA and aprotinin or by the use of specially prepared somatostatin-free plasma. Furthermore, in the presence of plasma, endogenous somatostatin does not dilute in parallel with synthetic cyclic somatostatin standard. We have, therefore, developed and validated a radioimmunoassay for somatostatin using prior extraction of the peptide onto leached silica glass. Tyrosine-II somatostatin was iodinated using lactoperoxidase and purified on ODS silica. This method is superior to iodination using chloramine-T with CMC cellulose purification, and gives a highly purified preparation with a shelf-life of at least eight weeks. Using this tracer and a specific antiserum, the limit of sensitivity of the assay was 10 pg/ml, with an intra-assay coefficient of variation of 12% (n = 16) and inter-assay coefficient of variation of 15% (n - 10). Parallelism has been demonstrated between standard synthetic cyclic somatostatin and all extracted plasma samples. The mean recovery of exogenous somatostatin from plasma was 78%. The fasting level of immunoreactive somatostatin at 0,900 hours in 40 normal subjects ranged from 17 to 81 pg/ml. Care is needed, however, when comparing these values with those obtained from other laboratories since standard preparations of somatostatin vary considerably in their immunopotency.

Antibody Specificity↗
PubMed1977

The effect of somatostatin on epinephrine-induced free fatty acid release in normal man.

Epinephrine and saline or cyclic somatostatin were infused into normal persons to study the effect of somatostatin on free fatty acid (FFA) release. Somatostatin had no effect on epinephrine-induced hyperglycaemia. It enhanced basal and epinephrine-induced FFA release, while the release of both immunoreactive insulin (IRI) and immunoreactive glucagon (IRG) was inhibited. We suggest that the rise in FFA levels may be due to either inhibition of IRI or another effect of somatostatin on fatty acid metabolism.

Adult↗
PubMed1974

Isolation and anaylsis of (Gp)nXp sequences of rat liver 5S RNA by means of restricted ribonucleas T2 hydrolysis.

Essentual difficulties arise when base number in oligoguanylic blocks and location of these blocks along the polynucleotide chain need to be determined in the course of determination of the nucleotide sequences in ribonucleic acids. To overcome this difficulty it is suggested to take advantage of a recently discovered resistance of phosphodiester bond between kethoxalated G and its 3'-neighbour against T(2) RNase hydrolysis 1,2. The approach is illustrated by analysis of 5S RNA from rat liver. Sequences of general formula (Gp)(n)Xp were isolated from T(2) RNase hydrolysate of 5 S RNA rapidly and quantitatively. The information obtained greatly facilitates the whole procedure of sequencing. It is expected that the method proposed would be effective for analysis of 5 S and 4 S RNA and for highmolecular weight fragments of ribosomal and viral RNAs.

Animals↗
PubMedDate not supplied

False positive reaction for carboxyhemoglobin in blood from liver tissue.

On spectrophotometric determination of carboxyhemoglobin in blood collected from the liver of three bodies at three days post-mortem, false positive results were found (5--15 per cent saturation), since samples of heart blood collected a few hours after death did not contain carboxyhemoglobin.

Accidents, Aviation↗
PubMedDate not supplied

The diagnostic value of postmortem blood glucose determinations in cases of diabetes mellitus.

In 24 cases of death in diabetic coma the peripheral venous blood showed glucose levels exceeding 3.5 mg/ml (mean value 7.76 mg/ml). In a control material of deaths of other causes the blood glucose was usually low and often zero, and all values were well below the lower limit of the diabetic concentrations. The acetone contents of the diabetic blood varied widely and were of limited diagnostic value. We conclude that glucose concentrations above 3.5 mg/ml in the peripheral blood indicate that death occurred in diabetic coma.

Blood Glucose↗