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Biomedical subjects

J G Allen

Publications and source records attributed to J G Allen.

At least 109 records · Page 6Linked to original sources
PubMed1984

The effect of bromazepam (Lexotan) administration on antipyrine pharmacokinetics in humans.

Six healthy volunteers were given a standard regimen of bromazepam (Lexotan) (6 mg t.d.s.) for five days. Compliance with the study protocol was demonstrated by measuring drug concentrations at steady state. Steady-state levels of 3-hydroxybromazepam were also determined. These were found to be much lower than the concentrations of bromazepam. Since the metabolite is known to be less active than the parent drug, it is likely that the metabolic will contribute little to the pharmacological effects of the drug in humans. Antipyrine pharmacokinetics were studied immediately before bromazepam administration was started, after the dosing schedule had been completed and one week after dosing had been discontinued. There were no significant changes in the disposition of antipyrine on any occasion. Therefore, although previous studies have demonstrated enzyme induction in laboratory animals given high doses of bromazepam, similar effects are unlikely to occur in humans being treated with therapeutic doses of the compound.

Adolescent↗
PubMed1984

A research design to predict required length of psychiatric hospital stay.

It is often an important clinical task to predict how long a given patient will need to be hospitalized, but past research efforts to provide an empirical basis for such predictions have not been highly successful. The authors propose a conceptual model for predicting length of stay that goes beyond previous research; they not only include a range of traditionally employed patient characteristics but also take into account the nature of the treatment goals and the availability of post-hospital treatment resources. The model forms the basis for an objective prediction procedure which will be tested in a large-scale research project on long-term hospital treatment outcome.

Aftercare↗
PubMed1983

Zinc toxicity in ruminants.

Four natural occurrences of zinc toxicity in sheep and one in calves were studied. To assist in the confirmation of a diagnosis of zinc toxicity, 2 experiments were conducted in which sheep were given toxic amounts of zinc. The clinical findings, clinical pathology, and gross and microscopic pathology are given. Clinical manifestations included inappetance, loss of condition, diarrhoea with dehydration or subcutaneous oedema, profound weakness and jaundice. Significant rises in the concentration of zinc were usually found in the liver, kidney and pancreas, but occasionally in only 1 or 2 of these organs. Many affected sheep were anaemic. Pathological changes were found in the pancreas, kidney, liver, rumen, abomasum, small intestine and adrenal gland. Lesions in the kidney and abomasum apparently made the most significant contribution to the deterioration in health of affected animals, but the pancreas was the only organ consistently affected. The degenerative changes in the pancreas were mainly restricted to the exocrine portion of the organ, and regeneration of the damaged tissue was observed although exposure to toxic amounts of zinc continued. Attention is drawn to the importance of the pancreas in the diagnosis of zinc toxicity and in estimating the period of exposure.

Animals↗
PubMed1982

The radiosensitizer Ro 03-8799 and the concentrations which may be achieved in human tumours: a preliminary study.

A new hypoxic cell radiosensitizer, Ro 03-8799, has been administered i.v. to 2 normal and 6 patient volunteers. Generally in non-necrotic tumours the concentrations obtained were 3 times greater than in plasma sampled at the same time. These observations added to the reports concerning toxicology in monkeys and rats and radiosensitizing efficiency in the laboratory, suggest that Ro 03-8799 may prove to be much more effective sensitizer than misonidazole in man.

Adult↗
PubMed1981

An evaluation of lupinosis in cattle in Western Australia.

A retrospective study of cases of bovine lupinosis submitted to this laboratory, and a trial in which 3 cows, 3 steers and 3 heifers were grazed together on toxic lupin stubbles, were carried out to determine further knowledge of this disease. It was found that what is presently recognised as bovine lupinosis can be divided into 2 distinct entities on the basis of liver pathology. Firstly, a fatty liver syndrome, which accounted for most outbreaks of the disease and most deaths, affected late-pregnant or recently calved cows, and is suggested to be a nutritional ketosis secondary to mild inappotence caused by lupinosis toxin. Secondly, a cirrhotic liver syndrome, which affected all classes of cattle, usually become apparent in winter and is considered to be the principal result of the direct action of lupinosis toxin. Cattle were less susceptible to lupinosis than sheep. Recommendations are made on grazing lupins by cattle.

Animals↗
PubMed1980

Prevention of ovine lupinosis by the oral administration of zinc sulphate and the effect of such therapy on liver and pancreas zinc and liver copper.

Three experiments were carried out using Merino wethers to investigate if oral administration of zinc sulphate would provide protection against the liver damage that occurs in lupinosis. At the same time, the effect of this zinc therapy on liver and pancreas zinc, and liver copper concentrations, was studied. The zinc therapy caused increases in liver and pancreas zinc concentrations, and a drop in the liver copper concentration. Administration of the toxins of Phomopsis leptostromiformis with the zinc increased the magnitude of these changes. Administration of 0.5 g zinc or greater per day, as zinc sulphate, reduced the liver damage caused by the toxins of P. leptostromiformis. The degree of liver protection provided by the zinc therapy varied both between animals within treatments and between treatments in different experiments. Zinc toxicity was encountered.

Administration, Oral↗
PubMed1980

Pharmacokinetics of alafosfalin, alone and in combination with cephalexin, in humans.

Alafosfalin is a phosphonodipeptide with significant activity as an antibacterial agent and as a potentiator of beta-lactam antibiotics. Studies in humans showed that oral doses of 50 to 2,500 mg were well absorbed, but some metabolic hydrolysis occurred before the drug reached the general circulation. Oral bioavailability was approximately 50% and was largely independent of dose. Alafosfalin has an elimination half-life of about 60 min and does not accumulate during chronic administration. Healthy volunteers excreted intact phosphonodipeptide in the urine. The recovery was dose dependent and increase from 6 +/- 1% after 50-mg doses to 17 +/- 1% after 2,500-mg doses. This change with dose occurred because the human kidney has a small, saturable capacity for reabsorbing the phosphonopeptide. Less alafosfalin was excreted in the urine of subjects with impaired glomerular function. When alafosfalin was coadministered with cephalexin, both compounds wer absorbed, distributed, and eliminated at virtually identical rates. Oral administration of 500 mg of the phosphonodipeptide plus 250 mg of the beta-lactam antibiotic gave approximately equal concentrations of the drugs in plasma, with a fourfold excess of cephalexin in the urine. This 2:1 combination is being tested in the clinic.

Alanine↗
PubMed1980

Adaptive functions of affect and their implications for therapy.

The adaptive functions of affects are formulated in relation to hierarchical conception of ego organization based on object-relations theory. Ego states are defined as relationship paradigms, consisting of particular self- and object representations and associated affective qualities of relatedness. Affect that is integrated in a conscious ego state as part of an experience of relatedness is distinguished from affect that occurs as an isolated mental content at the structurally subordinate level of cognition. In the latter form, affect may function as a signal of disequilibrium to the ego, potentially resulting in consolidation of the ego state in consciousness and awareness of the associated relationship. The potential signal properties of the wide range of affects are best understood on the basis of the associated object-relations paradigms. Affect provides especially useful interpretive material for both therapist and patient because of its intrinsic association to ego states and object relations. However, the fashion in many current therapies of encouraging affect expression for its own sake is often misdirected; it is better to orient the work more directly toward understanding and altering object relations.

Adaptation, Psychological↗
PubMed1979

The effect of lupinosis on liver copper, selenium and zinc concentrations in merino sheep.

Merino wether weaners were exposed to toxic lupin stubbles for periods of one, two and six to nine weeks, and the effect on their liver copper, selenium and zinc concentrations studied. After the one week period there was a slight decrease in liver copper and selenium concentrations in sheep severely affected with lupinosis. This was attributed to loss of these elements from necrotic cells, and greatly increased quantities of fat in the liver. In the same period liver zinc concentrations declined and were negatively correlated with the degree of liver injury. After two weeks or more of exposure to toxic lupins a positive correlation existed between both the liver copper and selenium concentrations, and the degree of liver injury. Furthermore, total liver copper and selenium levels were also positively correlated with the degree of liver injury. Liver zinc concentrations were negatively correlated with the degree of liver injury. It is suggested that when the liver is under the influence of the toxins causing lupinosis for more than two weeks, it stores copper and selenium, and loses zinc.

Animals↗