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Biomedical subjects

J Perry

Publications and source records attributed to J Perry.

At least 271 records · Page 15Linked to original sources
PubMed1980

Marrow cells from patients with untreated pernicious anaemia cannot use tetrahydrofolate normally.

Folate analogues were added to human bone marrow cells to determine their effect on deoxyuridine utilization in the deoxyuridine suppression test. Formyltetrahydrofolates fully corrected the impairment of dU utilization in pernicious anaemia marrows but tetrahydrofolate was relatively ineffective. All these analogues were effective in megaloblastic marrows from folate deficient patients. Formyltetrahydrofolates also enhanced dU utilization by normal human marrows whereas methyltetrahydrofolate reduced its use. In terms of the methylfolate trap hypothesis, the expectation that cobalamin-deficient marrows would be able to use tetrahydrofolate normally was not realized.

Anemia, Megaloblastic↗
PubMed1980

Inactivation of methionine synthase by nitrous oxide.

Exposure of rats to a 50% N2O/oxygen mixture led to a rapid loss of methionine synthase activity in both liver and brain. This enzyme has vitamin B12 as a cofactor. There was impaired conversion of deoxyuridine to deoxythymidine by bone marrow cells and this defect followed loss of methionine synthase activity. There was no homocystinuria. Withdrawal of N2O was followed by a relatively slow recovery of methionine synthase activity over four days. The inactivation of vitamin B12 by N2O promises to be a valuable tool in the study of vitamin B12 metabolism.

5-Methyltetrahydrofolate-Homocysteine S-Methyltran↗
PubMed1980

Dynamic gait electromyography study in Duchenne muscular dystrophy (DMD) patients.

Preoperative and postoperative dynamic gait electromyography (EMG) weas performed on 15 patients 8 to 13 year of age with Duchenne's muscular dystrophy who underwent Achilles tendon lengthening and posterior tibial tendon transfer anteriorly through the interosseous ligament for correction of equinus and equinovarus foot deformities. The muscles tested preoperatively (anterior tibial, soleus, gastrocnemius, posterior tibial, peroneal longus, and peroneal brevis) showed phase changes. It is believed that patients with weakened leg muscles fire multiple muscle groups out of phase in an attempt to overcome the action of the stronger muscles, thus stabilizing the limb for ambulation. Postoperative EMGs, performed with the patients walking in long leg braces after the deformity had been corrected, showed little activity in the muscles tested. As the patients became dependent on the brace, the need for the muscles to be active out of phase was eliminated. The transferred posterior tibial muscle appeared to be active both clinically and electromyographically.

Achilles Tendon↗
PubMed1980

Functional evaluation of the pes anserinus transfer by electromyography and gait analysis.

The effectiveness of the pes anserinus transfer, proposed by Slocum and Larson to control anteromedial rotatory instability of the knee, depends on the pes anserinus muscles contracting at times when the instability threatens the patient's function. To examine the activity of the transferred pes anserinus muscles, quantitated dynamic electromyography, isometric testing of muscle strength, and gait-analysis techniques were employed. Seven normal subjects and nine patients who had undergone pes anserinus transfer for anteromedial rotatory instability were tested. In contrast to the normal subjects, who demonstrated pes anserinus muscle activity primarily during swing phase, the patients displayed conspicuous activity of the semitendinosus, gracilis, and sartorius tendons during stance phase. Quantitated electromyography indicated that the pes anserinus muscles worked harder in the patients than in the normal subjects, and more effort was required from the muscles of patients with poor results than from those of patients with good results. All of the patients also demonstrated reduction of single-limb support time, as well as a shorter stride length and reduced gait velocity. We concluded that the pes anserinus transfer is kinetically sound. Since instability of the knee is a functional defect that is present during stance, the finding of marked activity of the pes anserinus muscles during stance phase in the patients but not in the normal subjects suggests that these muscles were being used to control the instability.

Adolescent↗
PubMed1979

Characterization of endogenous folate and incorporation of labelled folates into the brain of the South African fruit bat.

Folate in the brain of the South African fruit bat consists of 10-formyltetrahydropteroyglutamic acid and the tri-, tetra- and penta- forms of 5-methyltetrahydropteroylglutamic acid. Following parenteral injection, only 5-[3H]-methyltetrahydropteroylglutamic acid was taken up by the brain, but none of a dose of 14C-labelled tetrahydropteroylglutamic acid was detectable. Only trace smounts of the 5-methyltetrahydropteroylglutamic acid were converted into the formyl compounds and a small amount of methyltetrahydropteroyltriglutamic acid appeared after 96 h. There was no significant difference in vitamin B-12-deficient animals.

Animals↗
PubMed1979

Dynamic electromyography and decision-making for surgery in the upper extremity of patients with cerebral palsy.

Seventeen children with cerebral palsy were selected for improvement in upper extremity function. Each had normal or nearly normal intelligence; each hand had good or mildly impaired sensibility; each arm had relatively good placement. Electromyograms with wire electrodes were utilized to study the patterns of activity of the planned tendon transfers. Only muscles with isolated activity in grasp were utilized to transfer in hands with weak grasp. Only muscles with isolated activity in release were utilized to transfer in hands with poor release.

Adolescent↗
PubMed1979

Stiff-legged gait in hemiplegia: surgical correction.

Selective tenotomy of one or two heads of the quadriceps based on electromyographic criteria improved knee flexion in hemiplegic patients who walked with a unilateral stiff-legged gait. The improvement was greatest in eight patients in whom the rectus femoris was released, either with or without release of the vastus intermedius, with activity in pre-swing stance and initial swing confined to those heads of the quadriceps; in these patients knee flexion improved an average of 20 degrees. Knee flexion improved an average of only 8 degrees in five patients in who activity was present in one head of the quadriceps that was not surgically released. No improvement in knee flexion occurred in seven of eight patients in whom activity was present in two or more of the quadriceps heads that were not surgically released.

Electromyography↗
PubMed1978

Selective inactivation of vitamin B12 in rats by nitrous oxide.

Exposure of rats to nitrous oxide rapidly inactivated the cytosol enzyme, methionine synthetase, but the mitochondrial enzyme, methylmalonyl CoA mutase, seemed to be unaffected, although both enzymes require vitamin B12.

5-Methyltetrahydrofolate-Homocysteine S-Methyltran↗
PubMed1978

Topical effects of 16,16 dimethyl prostaglandin E2 on gastric acid secretion and mucosal permeability to hydrogen ions in dogs.

The effects of luminal instillation of 16,16 dimethyl PGE2 (dmPGE2) on gastric acid secretion and back diffusion of H+ were studied in anaesthetised dogs which were prepared with a segment of the greater curvature of the stomach mounted in a double lumen chamber. This model permitted simultaneous evaluation of two segments of mucosa, one control and the other test, supplied by the same vascular pedicle. Imfusion of histamine (1.0 microgram/kg/min, intravenously) stimulated brisk acid secretion in both chambers. Topical application of 25 microgram dmPGE2 in 20 ml 0.3 M HC1 to the test chamber for 30 minutes prevented acid secretion from the test mucosa during a second histamine infusion. Since the control chamber showed no evidence of inhibition this indicates that dmPGE2 acted directly on the secretory cells, rather than after absorption from the bloodstream. This observation, however, does not exclude a possible local effect on mucosal blood flow. Direct exposure of the gastric mucosa to dmPGE2 increased the rate of back diffusion of H+ because of disruption of the permeability barrier, indicated by increased H+ back diffusion, Na+ efflux, and a reduction in potential difference. However, H+ loss was small compared to the reduction in acid output.

Animals↗
PubMed1977

Use of medicines in general practice.

The prescriptions issued by general practitioners to a population of about 40 000 people were studied. During one year 53-8% of all males and 65-7% of all females had at least one drug dispensed. The proportion receiving medicines increased with age and was higher among females at all ages. Psychotropic drugs were prescribed more often than any other group and accounted for almost one-fifth of all prescriptions. Altogether 9-7% of the males in the population and 21-0% of the females received at least one psychotropic drug during the year. Among women aged 45-59 33-0% received a psychotropic drug, and 11-2% were given an antidepressant. Althoug antimicrobial drugs were prescribed less often than psychotropic drugs, they were given to more people.

Adolescent↗