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Biomedical subjects

J Walters

Publications and source records attributed to J Walters.

At least 91 records · Page 5Linked to original sources
PubMed1983

Graft pretreatment with cyclosporin A. Long-term study including four trials in one and a half years.

Four trials were conducted to establish whether Cyclosporin A (Cy A) could be used as a graft pretreatment to prolong the graft function and animal survival of kidneys transplanted into bilaterally nephrectomized mongrel dogs. The first nonrandomized trial analyzed various parameters such as concentration, flush temperatures, effect of reflushing, and the need for subsequent minimal immunosuppression. By analyzing data from the ten groups in this trial, we established that 50 mg/l Cy A could be flushed successfully at either 4 C or 25 C without nephrotoxic effects. This concentration was found to prolong graft function and animal survival in some animals greater than 100 days. Reflushing the kidney after primary graft pretreatment with Cy A did not entirely remove the immunosuppressive effect of the drug as significant prolongation of survival also was observed in this group. In addition, minimal immunosuppression with azathioprine was necessary to observe a delay in the onset of rejection and prolongation of animal survival when Cy A was used for graft pretreatment. Trials 2 and 4 compared the efficacy of the original batch that was obtained later. The effects observed in Trial 1 and reproduced in Trial 3, which were randomized and double blinded using the original batch, were not seen in either Trials 2 or 4. This may have been related to the amount of time that the Cy A was dissolved in ethanol prior to its use or the batch of Cy A utilized. These preliminary results indicate that Cy A, when used for graft pretreatment under certain conditions, can delay the onset of rejection and prolong animal survival of transplanted renal allograft recipients.

Animals↗
PubMed1982

Folate metabolism in man: the effect of malignant disease.

The metabolism of [2-14C]+[3', 5', 7, 9-3H] folic acid and [214C]+[3', 5', 7, 9-3H] 10-formylfolate was studied in hospital inpatients. Metabolites detected in the urine after folic acid feeding included the unchanged compound, other folates and a number of breakdown products, such as p-acetamidobenzoyl-L-glutamate and p-acetamidobenzoate. This confirms the existence of a folate catabolic pathway in man. Patients with malignant disease excreted less of the dose in urine, incorporated more into the reduced folate pool, and showed decreased catabolism of folate, when compared to controls. 10-Formylfolate was excreted largely unchanged, and appears not to be reduced by man. Also 10-formylfolate interfered with the reduction of folic acid given simultaneously.

4-Aminobenzoic Acid↗
PubMed1980

Interventions and the development of dominance relationships in female baboons.

Dominance relationships between adult and adolescent female yellow baboons, Papio cynocephalus, were studied in Amboseli Park, Kenya. Adolescents attempted to become dominant to some females (called 'targeted females') while remaining subordinate to others. Agonistic relationship with targeted females passed through a sequence of stages before the younger female achieved dominance. An examination of nondyadic agonistic interactions revealed that adolescents frequently intervened against targeted females, but never against nontargeted females, and that others sometimes aided adolescents against targeted females, but aided nontargeted females against adolescents. Interveners were unrelated adult females and other adolescents as well as kin. Targeting was determined by birth rank (the rank of the adolescent's mother at the time of the adolescent's birth) and did not depend on interventions by the mother.

Age Factors↗
PubMed1978

Delinquent and non-delinquent males' perception of their fathers.

The purpose of this study was to investigate the differences in delinquents' and non-delinquents' perceptions of their fathers, and the relation between their perceptions and selected background and familial variables. Utilizing a sample of 330 Ss, delinquency was found to be associated with: (a) lack of a warm, loving, supportive relationship with the father; (b) minimal paternal involvement with children; (c) high maternal involvement in the lives of youth; (d) broken homes; and (e) feelings of anomie.

Adolescent↗
PubMed1977

Amphetamines, growth hormone and narcolepsy.

1 Plasma amphetamine and growth hormone levels have been measured in eight normal and twenty-six narcoleptic subjects following a single dose of (+)-amphetamine (20 mg) or (-)-amphetamine (20 mg) by mouth. 2 Peak plasma levels and the shape of the plasma amphetamine-time curve were similar with both isomers in normal and narcoleptic subjects. 3 In most normal subjects both (+)-and (-)-amphetamine (20 mg) caused an increase in the plasma concentration of growth hormone. The two isomers were approximately equipotent in this respect. Neither (+)- nor (-)-amphetamine (20 mg) caused an increase in plasma growth hormone concentration in narcoleptics. 4 Following amphetamine (30 mg), two of six narcoleptic subjects had an increase in plasma growth hormone concentration. 5 Levodopa (250 mg) with (-)-alpha-methyldopa hydrazine 25 mg (Sinemet) by mouth, caused a rise in plasma growth hormone concentration in most normal subjects. The magnitude of the Sinemet-induced rise in plasma growth hormone concentration in narcoleptics was less than in normal subjects.

Adult↗
PubMed1977

Plasma DOPA levels and growth hormone response to levodopa in parkinsomism.

It has been suggested that the therapeutic response to levodopa in patients with Parkinson's disease may be related to changes in plasma growth hormone concentration. In order to examine this problem, we have determined plasma DOPA and growth hormone levels after a standard oral levodopa load in 32 patients with Parkinson's disease. Levodopa caused an increase in plasma growth hormone concentration in 30 subjects. The magnitude and timing of this growth hormone response was not related to the clinical response, the presence or absence of response swings, or the occurrence of dyskinesias. The growth hormone response to levodopa is normal in patients with Parkinson's disease and not altered by long-term levodopa treatment.

Adult↗
PubMed1976

Bromocriptine treatment in Parkinson's disease.

Thirty-one patients with Parkinson's disease were treated with the ergot alkaloid bromocriptine, a drug which stimulates dopamine receptors. Bromocriptine had a slight therapeutic effect in patients on no other treatment and an additional effect in patients on levodopa. The mean optimum dosage of bromocriptine, established over a 12 week period, was 26 mg daily. In 20 patients bromocriptine was compared with placebo in a double-blind controlled trial. Active treatment caused a significant (P less than 0.02) reduction in total disability and akinesia scores. The least disabled patients showed the greatest response. Side-effects of bromocriptine--nausea, vomiting, hallucinations, and abnormal involuntary movements--were similar to nature to those of levodopa. In most normal subjects, bromocriptine causes an increase in plasma growth hormone concentration. This was determined in 20 patients with Parkinson's disease after 1-15 mg bromocriptine. Only a single patient showed an obvious increase up to 120 minutes after dosage. Bromocriptine was not effective treatment in two patients who had not previously responded to levodopa and replacement of this drug by bromocriptine in patients with end-of-dose akinesia after chronic levodopa treatment did not totally abolish response swings.

Aged↗