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Biomedical subjects

R Thomas

Publications and source records attributed to R Thomas.

At least 649 records · Page 36Linked to original sources
PubMed1980

Salmonellae on posts, hand-rails and hands in a beef abattoir.

Counts of salmonellae were done by the most probable number technique on samples collected from the hands of abattoir workers as well as on samples from hand-rails and posts regularly touched by the workers. Salmonellae were isolated from the hands of 52% of the workers who handled the hide. They had the highest average counts with counts ranging from 0 to greater than 3663 salmonellae. The remaining workers on the slaughter floor and those in the boning room had generally lower counts with contamination rates of 28% and 45% respectively. Only 3 of the 100 samples collected from the hand-rails and posts contained salmonellae. The average count was 0.11 per 100 cm2.

Abattoirs↗
PubMed1980

Microbiological quality of Queensland stockfeeds with special reference to salmonella.

One hundred Queensland stockfeeds were examined for their counts of total aerobic bacteria, coliforms, fungi and salmonellas. The total aerobic bacteria, coliform and fungal counts were significantly higher (P < 0.005) for mashes than for crumbles and pellets and salmonellas were isolated from significantly more (P < 0.005) mashes (64%) than pellets and crumbles (8%). Counts of less than 1 salmonella per 100 g were found in 36.4% of the 44 positive feeds. The remainder of the counts ranged from 1.2 per 100 g to greater than 147 salmonellas per 100 g feed.

Aerobiosis↗
PubMed1980

Two-dimensional analysis of proteins sedimenting with simian virus 40 chromosomes.

The nonhistone proteins sedimenting in low-salt glycerol gradients with simian virus 40 chromosomes were analyzed by two-dimensional gel electrophoresis, utilizing nonequilibrium pH gradients as the first dimension and sodium dodecyl sulfate-gel electrophoresis as the second dimension. By densitometric quantitation of the radiolabeled proteins present in each fraction of the gradients, it was possible to identify sedimenting with all or a fraction of the simian virus 40 chromosomes. VP-1 sedimented with simian virus 40 chromosomes; additional evidence for its binding to chromosomes was obtained by immunochemical techniques. Four proteins (Mr 25,000, pI 6.0; Mr 32,000, pI 7.2; Mr 35,000, pI 8.5; and Mr 80,000, pI 7.2) sedimented with specific subsets of chromosomes.

Centrifugation, Density Gradient↗
PubMed1979

Cardenolide analogs. An explanation for the usual properties of AY 22241.

AY 22241 (AY) was compared with digitoxigenin with respect to effects on myocardial contractility and inhibition of Na+, K+-ATPase. Ay was less potent than digitoxigenin but otherwise showed the same type of rapid onset and rapid reversal of activity usually associated with genins. Since AY is a glycoside, its behaviour was regarded as anomalous since glycosides usually show both slow onset and slow reversal of activity. Attempts were made to account for the genin-like properties of AY in terms of the model for the digitalis receptor proposed by Thomas et al. (1974a,b). It is suggested that the low potency and genin-like properties of AY may be due to the fact that the steroid is attached to the lactone through the carbon atom that is alpha to the carbonyl group. This feature could result in non-alignment of the sugar residue with the sugar binding site and might also reduce the effectiveness of the interaction of the steroid moiety with its binding site. A notable feature of AY toxicity was its extremely rapid progression to irreversible fibrillation.

Animals↗
PubMed1979

Cardenolide analogues: 10--characterization of cardiac glycosides by chemical ionization mass spectrometry.

The potential of chemical ionization mass spectrometry for the characterization of naturally occurring and semi-synthetic cardiac glycosides has been investigated. Methane, isobutane and ammonia were used as reactant gases. With the exception of ouabain, the ammonia chemical ionization mass spectra of the cardiac glycosides examined in this work contained abundant [M + NH4]+ions and abundant fragment ions formed by cleavage of glycoside bonds. Ammonia chemical ionization mass spectrometry was found to provide a rapid and sensitive method for the characterization of the products of glycosidation reactions. In contrast, the methane and isobutane chemical ionization mass spectra of the cardiac glycosides, with the exception of ouabain, did not contain protonated molecular ions and did not contain abundant fragment ions above m/z 400.

Ammonia↗
PubMed1979

Bacteriological aspects of the disposal of manure from beef cattle.

Manure, collected from cattle housed in yards, was spread on experimental plots at the rate of 120 tonnes per hectare per annum. The manure was applied to 2 plots at 6-monthly intervals while a further 2 plots received monthly applications. Samples of manure soil, run-off and ground waters were examined for their counts of total aerobic bacteria, coliforms, faecal coliforms and for the presence of salmonellae. Comparison of the bacterial counts from samples from the test plots to those of the control plots showed that no change occurred in the levels of coliforms or faecal coliforms over the 3 years of manure application. One hundred and fifty-seven isolations of salmonella were made from the soil and water samples, but only 51 could be attributed to the manure. No difference was observed in the effects of different application frequencies.

Animals↗
PubMed1979

An enzyme-linked immunosorbent assay for the detection of canine antibodies to canine adenoviruses.

An enzyme-linked immunosorbent assay was used to detect canine immunoglobulin G antibodies specific for infectious canine hepatitis virus and the serologically related canine adenovirus Type 2. The sequential development of homologous and heterologous antibodies was measured by the enzyme-linked immunosorbent assay and serum neutralization tests in two groups of dogs which were experimentally infected with either infectious canine hepatitis virus or canine adenovirus Type 2. Both tests were comparable in their abilities to detect the development of homologous and heterologous antibodies. Homologous antibodies were detected earlier and to a higher titer in both tests. There was a 98% agreement between the serum neutralization test and the enzyme-linked immunosorbent assay when sera from 224 random-source dogs were examined for infectious canine hepatitis virus antibodies. The enzyme-linked immunosorbent assay was found to be a highly efficient and rapid test to determine the immune status of dogs to infectious canine hepatitis virus and canine adenovirus Type 2.

Adenoviridae↗
PubMed1979

Insulin resistance in peripheral tissues after a burn injury.

The glucose uptake of a perfused, skin-covered preparation of muscle taken from the rat was altered by prior burn injury to the animal. Animals receiving an 8% deep burn to the back 24 hours prior to testing had a glucose uptake (5.9 +/- 0.85 microM/100 gm/min) which was depressed compared with control nonburned preparations (8.4 +/- 0.34 microM/100 gm/min) (P less than 0.025) at low insulin concentration (35 microU/ml). Higher insulin concentrations (160 microU/ml and 16 microU/ml) produced significant increases in the glucose uptake of both the burned and control animals. At the highest insulin level (16 microU/ml), there was no significant difference between burned and control animals. Preparations from animals burned five days prior to study showed a glucose uptake which was not decreased as compared with control animals at the low level of insulin (35 microU/ml) (7.4 +/- 0.62 microM/100 gm/min), but higher levels of insulin (160 microU/ml and 16 microU/ml) failed to produce a significant increase in glucose uptake (8.4 +/- 0.64 microM/100 gm/min and 8.6 +/- 0.92 microM/100 gm/min, respectively). The values differed significantly (P less than 0.05) from control preparation (11.5 +/- 0.54 microM/100 gm/min) at the insulin level of 16 microU/ml. Two different patterns of altered sensitivity to increased insulin concentrations were noted, depending on the stage of injury. The altered metabolic status of peripheral tissues does contribute to the insulin resistance pheonomenon observed after a burn injury.

Animals↗