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Biomedical subjects

D Roberts

Publications and source records attributed to D Roberts.

At least 415 records · Page 23Linked to original sources
PubMed1976

The natriuretic effect of p-aminohippurate in man.

The effects of p-aminohippurate (PAH) on electrolyte clearances were measured in 8 human volunteers. At plasma PAH levels used to measure renal plasm flow, the only significant increase was in sodium clearance, while with PAH levels used to measure maximum tubular secretion, the clearances of sodium, potassium and phosphorus were all significantly increased. The antriuresis combined with a depression of free water clearance and the absence of a chloruresis led to the conclusion that PAH- changed the anion composition of the filtrate delivered to the ascending limb, thus interfering with coupled Na+ reabsorption. This finding must be taken into account when electrolyte excretion is being measured during PAH infusion. A similar mechanism may operate in patients with chronic uremia whose endogenous hippurate level is increased.

Aminohippuric Acids↗
PubMed1975

The isolation of salmonellas from British pork sausages and sausage meat.

Between 1969 and 1974, 1467 packets (3309 samples) of pork sausages and sausage meat produced by two large and two medium sized manufacturers and several local butchers were examined for the presence of salmonellas. Of these, 435 packets (786 samples) were found to contain salmonellas, but there was a wide variation in the isolation rates according to the producer. The salmonella incidence in samples from several small and two medium sized producers was low (0-11%) while the results from the two large producers investigated showed a striking difference, the rate of salmonella contamination in the product of one was low (about 2%) and in that of the other consistently high (40-60%). A comparison of liquid enrichment media, incubation temperatures and selective agar media was also carried out to determine the most efficient combination for the isolation of salmonellas from minced meat products. The results showed that (a) incubation of enrichment cultures at 43 degrees C. yielded a consistently greater number of salmonella isolations that at 37 degrees C., regardless of plating medium, (b) tetrathionate broth A (Rolfe) was superior to selenite broth as en enrichment medium at both 37 and 43 degrees C. and (c) brilliant green agar gave better results than deoxycholate citrate sucrose agar and bismuth sulphite agar as a selective medium.

Animals↗
PubMed1975

Radioimmunoassay of plasma vasopressin in physiological and pathological states in man.

A radioimmunoassay method for the measurement of arginine-vasopressin (AVP) in human plasma has been developed which requires 5 ml of plasma and has a lower limit of detection of 1-8 pg/ml plasma. Arginine-vasopressin was found to be stable in whole blood for up to 1 h at room temperature and for at least 4 h at 4 degrees C, while in plasma stored at -20 degrees C no loss was seen over 10 days. Dehydration and rehydration in normal subjects produced appropriate changes in AVP concentration but there was considerable variability in the levels attained by individual subjects and no obvious correlation with plasma osmolality. No consistent increase in plasma AVP concentration was seen on change of posture from the recumbent to the upright position. Vigorous exercise produced a marked rise in plasma AVP concentrations in most subjects which could not be attributed simply to an increase in plasma osmolality. In fusion studies with Pitressin in normal subjects showed a mean half-life of 6-4 min with an overall plasma clearance rate of 8-5 ml/min/kg body weight and a mean volume of distribution of 5-33 l. In patients with a biochemical picture suggestive of inappropriate antidiuretic hormone secretion, markedly raised plasma AVP concentrations were found only in patients with bronchial carcinoma.

Arginine Vasopressin↗
PubMed1972

Observations on procedures for thawing and spit-roasting frozen dressed chickens, and post-cooking care and storage: with particular reference to food-poisoning bacteria.

A comparison was made of four methods of thawing frozen chickens and an average thaw time for each method was determined.Fully and partially thawed chickens, inoculated with salmonellas, Clostridium welchii and Staphylococcus aureus were cooked in a spit-roasting oven at different temperatures for different lengths of time. The chickens were examined freshly cooked and after storage under various conditions.Spit roasting fully thawed chickens until the outer skin was golden brown was sufficient heat-treatment to kill salmonellas and Staph. aureus but Cl. welchii could survive. Salmonellas could also survive if the chickens were not fully thawed before cooking.Incorrect storage after cooking was shown to encourage the growth of pathogens.The incidence of intestinal pathogens in frozen dressed chickens and environmental hazards in spit-roasting establishments were also studied. Of raw chickens examined 35% contained salmonellas (9 serotypes), 63% contained Cl. welchii and 63% Staph. aureus.

Animals↗