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Biomedical subjects

G T Davies

Publications and source records attributed to G T Davies.

At least 19 recordsLinked to original sources
PubMed1994

Simulation of the economic impact of transmissible gastroenteritis on commercial pig production in Australia.

A simulation model (AUSPIG) was used to predict the effect of an increase in piglet deaths, and a reduction in growth rate and an increase in feed conversion ratio of grower pigs on the profitability of two herds representative of the Australian pig industry caused by the introduction of transmissible gastroenteritis virus (TGE) into those herds. For each herd, mortality rates for piglets under 1 week of age of 50% and 95% were assumed to represent a 'moderate' and a 'severe' outbreak, respectively. A reduction in net revenue of 70% was predicted to occur in the 6 months after a 'moderate' outbreak of TGE (100% for a 'severe' outbreak). This represents a total loss of between $260 and $330 per breeding sow in the 12 months after infection with the TGE virus. The likely financial impact of an outbreak of TGE on an Australian piggery is substantial and should be considered when addressing quarantine issues.

Animals↗
PubMed1981

The predictive value of the serum digoxin concentration in the management of hospitalized patients.

Serum digoxin concentration (SDC) was compared with clinical and ancillary predictors as a guide to adjustment of digoxin dose and as a test for digitalis toxicity in a total of 76 hospitalized patients during a period of 9 months. The mean SDC (3.6 +/- 2.5 nmoles/liter) associated with unexpected discontinuation of therapy was significantly higher (p less than 0.001) than that (1.1 +/- 0.6 nmoles/liter) associated with unaltered digoxin dose, while the mean SDC (0.6 +/- 0.4 nmole/liter) associated with unexpected dose increase was significantly lower (p less than 0.05). There was no significant association between other pharmacokinetic or pharmacodynamic predictors and therapeutic intention. There was a 13% incidence of confirmed digitalis intoxication. The mean SDC (3.6 +/- 1.9 nmoles/liter) of patients presenting and confirmed as digitalis toxic was significantly higher (p less than 0.001) than that (1.4 +/- 0.6 nmoles/liter) involving a situation in which digitalis toxicity could not initially be excluded by other means. The predictive value of an SDC greater than or equal to 2.6 nmoles/liter for toxicity was 80%, and its efficiency for diagnosing both toxicity and nontoxicity was 95%. The SDC was thus shown to be a valid test of digitalis toxicity and to provide extraordinary information enabling the clinician to modulate digoxin therapy precisely.

Cardiovascular Diseases↗
PubMed1980

Thyroid, renal, and hepatic function tests following cholecystography with high-dose contrast agents.

Serum biochemical tests were observed for about three weeks following oral cholecystography with fractionated high doses (6 g) of iopanoic acid (Telepaque) or sodium ipodate (Biloptin) in 24 and 29 patients, respectively. Both agents produced similar effects. No significant changes were seen in renal or hepatic function except for a mild increase in bilirubin on day 22. Serum urate decreased 10% on day 4, but the change was not significant. On days 4 and 11, there were significant increases in thyroid-stimulating hormone, thyroxine and free thyroxine index, and a moderate fall in triiodothyronine. Reverse triiodothyronine increased sharply on day 4. The pattern of changes observed suggests that these contrasts interfere with the extrathyroidal deiodination of iodothyronines. The temporary rise in thyroxine and free thyroxine index exceeded reference ranges in about half of all subjects, but they remained clinically euthyroid. Thyroid function tests should be interpreted with caution within three weeks of cholecystography.

Adult↗
PubMed1980

Fractionated dose cholecystography: a comparison between iopanoic acid and sodium ipodate.

Two randomised groups of 100 subjects each, undergoing oral cholecystography, were given either a 6 g fractionated dose of iopanoic acid (Telepaque) or sodium ipodate (Biloptin) to determine the relative merits of this dose schedule. Exclusions to the study were pregnancy and iodine sensitivity. Calculi or abnormal gallbladder opacification were present in 45% of subjects. Both agents were equally effective in demonstrating abnormalities, although bile duct visualisation was better using iopanoic acid (P less than 0.05). Of 46 subjects with abnormal cholecystograms subsequently undergoing surgery, all had the diagnosis confirmed. Side effects occurred in 63% of all subjects, being twice as common in those taking iopanoic acid (P less than 0.01). Sodium ipodate in a large fractionated dose is favoured because of the lower occurrence of side effects without loss of diagnostic accuracy.

Cholecystography↗
PubMed1979

Monofixational intermittent exotropia.

The surgical correction of intermittent exotropia occasionally results in a monofixational sensory pattern. Stereopsis as a measure of bifixation was studied preoperatively and postoperatively in 39 cases of intermittent exotropia. Of 26 patients with bifixation, 25 remained so after surgery. Of 13 patients with monofixation, 11 remained unchanged by surgery, one improved, and one lost all binocularity. The presence of preoperative monofixational intermittent exotropia, to explain a monofixation result from intermittent exotropia surgery, is proposed.

Adolescent↗
PubMed1978

Pediatric intraocular knife.

An intraocular knife was developed that is of fine sharpness and small size to permit easy use in the eyes of young children.

Adult↗
PubMed1976

Gallbladder disease. Prevalence in a South Wales industrial town.

In a weighted random sample of the specially enumerated population of a South Wales industrial town, examined by cholecystography for gallstones, the overall prevalence rates were 6.2 per cent for men 45 to 69 years of age and 12.1 per cent for women of the same ages. Contrary to our expectation there was no marked increase in prevalence with age in either sex. Symptoms of dyspepsia said to be suggestive of gallstones were found with approximately equal frequency in those with and without gallbladder disease.

Age Factors↗
PubMed1972

Natural history of patients with x-ray-negative dyspepsia in general practice.

When 102 patients with dyspepsia who had normal findings on barium-meal examination in 1964 were interviewed in 1970, 85 of them (76%) were symptomatically improved, and only three were later shown to have a peptic ulcer. This suggests that "x-ray-negative dyspepsia" has a good prognosis in a general practice setting.

Age Factors↗