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Biomedical subjects

J Perry

Publications and source records attributed to J Perry.

At least 163 records · Page 9Linked to original sources

Oxidation of 5-methyltetrahydrofolate in cobalamin-inactivated rats.

Rats were exposed to nitrous oxide, which inactivates cob(I)alamin (Cbl). As in air-breathing rats methionine administration led to the conversion of hepatic 5-methyltetrahydrofolate (MeH4 folate) into formyltetrahydrofolate. The recovery of MeH4 folate levels in liver after its oxidation initiated by methionine was noted and the rate compared with that for air-breathing rats. Oxidation of MeH4 folate was less complete and occurred more slowly in Cbl-inactivated rats as compared with controls. However, recovery of MeH4 folate levels was more rapid in Cbl inactivation. S-Adenosylmethionine did not produce a significant change in MeH4 folate levels in Cbl-inactivated rats, whereas it did so in air-breathing animals.

Animals↗

Regulation of 5-methyltetrahydrofolate synthesis.

After an intraperitoneal injection of 100 mumol of methionine to rats, there is rapid oxidation of the methyl group of hepatic 5-methyltetrahydrofolate to formate and CO2. Recovery of the methylfolate level starts 2.5 h after the methionine injection, when the hepatic methionine level and the S-adenosylmethionine/S-adenosylhomocysteine ratio have returned to baseline values. S-Adenosylmethionine concentration is still elevated at this time.

Animals↗

Cobalamin-folate interrelations.

Cobalamin deficiency leads to impaired folate function as demonstrated by markedly impaired single-carbon unit transfer into purine, thymidine and methionine. This occurs in the total absence of 'methylH4folate trapping'. In cobalamin deficiency there is impaired synthesis of formylH4folate and raised levels of endogenous formate in blood and liver. FormylH4folate and methionine reverse the effects of cobalamin deficiency. Methionine provides formate via its metabolism to methylthioribose. Recently it has been suggested that the neuropathy of cobalamin deficiency is due to impaired methylation but this was not confirmed. It is likely that defects demonstrated in marrow and liver are also the explanation for the effects of cobalamin deficiency in the CNS.

Anemia, Megaloblastic↗

Pelvic exercise and gait in hemiplegia.

The purpose of this study was to describe and compare the gait of 20 patients with hemiplegia secondary to cerebrovascular accident (CVA) before and after a treatment regimen of resisted pelvic motions. Ten women and 10 men were studied, with a mean age of 48 years and a mean duration post-CVA of two months. Nine subjects (45%) were right hemiplegic, and 11 subjects (55%) were left hemiplegic. Treatment consisted of four sets of five repetitions each of manually resisted pelvic anterior-elevation and posterior-depression movements on the involved side. An insole footswitch system, knee electrogoniometer, and force walking aid were used in gait analysis performed before treatment, immediately after treatment (posttest 1), and 30 minutes after treatment (posttest 2). Results showed significant overall improvement in gait in posttest 1 (p less than .005) compared with the pretest. This improvement, however, was not maintained in posttest 2. Ten patients improved overall in posttest 1; only 4 patients also showed improvement in posttest 2. The major improvements seen immediately after treatment were observed in stance stability and limb advancement in the involved limb. More research is needed to identify an optimum treatment with carry-over using this technique.

Adult↗

Dynamic EMG analysis of torque transfer in professional baseball pitchers.

Fifteen professional baseball pitchers underwent active pitching motion analysis of the abdominal oblique, rectus abdominis, lumbar paraspinous and gluteus maximus muscles bilaterally via surface electrode evaluation. Baseline resting and isometric maximum values were obtained and active data referenced against these for comparison. The muscle activity then was measured during the pitching sequence and analyzed in each of the five pitching phases. The abdominal oblique, lumbar paraspinous and rectus abdominis contralateral to the pitching arm and the ipsilateral gluteus maximus all had increases in activity level of 75 to 100% during the active pitching motion. Using these data indicating specific muscle group patterns with clinical and performance data, we hope to minimize injuries and maximize pitching performance.

Abdominal Muscles↗

Cost-related variables: a pilot study.

The advent of prospective payment systems prompts nurses to examine cost-related factors in demonstrating savings resulting from quality care. The clinical nurse specialist plays an active role in the examination of variables influencing costs for patients within the specialty. This pilot study utilized a retrospective chart audit of 142 women falling within Diagnostic-related Group 355 (non-radical hysterectomy, age less than 70 years, without comorbid condition or complication) during 1985 to identify demographic, illness/treatment-related, and discharge variables related to charge variance. Independent (length of stay, p less than 0.001 and previous admission, p = 0.066) predictors of charge variance were found among the 14 variables studied. The value of the research as a model for other practitioners is discussed.

Costs and Cost Analysis↗

The effect of the CAT-CAM above-knee prosthesis on functional rehabilitation.

Five, rehabilitated, unilateral above-knee amputees (average age, 34.4 years) using quadrilateral sockets were converted to Contoured Adducted Trochanteric-Controlled Alignment Method (CAT-CAM) sockets to determine the effect on ambulatory function. Patients were evaluated before and after conversion for subjective acceptance, gait deviations, relative femoral shaft inclination, coronal-plane hip abduction torque, and ambulatory metabolic demands. The CAT-CAM socket was subjectively rated superior by four patients. Most gait deviations improved or disappeared. Femoral shaft inclination angles improved an average of 6.5 degrees toward adduction by roentgenographic measurements in four patients. Film records suggest that the compensatory lateral trunk lean, seen in patients with quadrilateral sockets, diminished after conversion. These four patients increased their customary gait velocities, and all showed a reduction in the quantity of oxygen consumed per meter traveled by up to 50%.

Amputation, Surgical↗

Functional recovery. A major risk factor for the development of postpoliomyelitis muscular atrophy.

A retrospective study was undertaken to identify potential risk factors for the development of progressive postpoliomyelitis muscular atrophy (PPMA). Patients with PPMA (n = 57) were compared with patients with a history of poliomyelitis but without a history of progressive weakness (n = 49). Patients who later developed PPMA had histories of more widespread acute paralysis, but relatively greater functional recovery. They were less disabled, and reported higher recent activity levels. Seventy-nine percent of the total variance between the PPMA and control groups could be accounted for by recovery alone (ie, severity minus disability). Functional recovery is generally attributed to reinnervation of sarcomeres by collateral sprouting from surviving lower motor neurons. Since degree of recovery predicts the risk of developing PPMA, our findings suggest that enlarged motor units may carry an increased susceptibility for dysfunction and/or degeneration.

Adult↗

Energy-speed relationship of walking: standard tables.

The energy expenditure of level walking was measured in 260 normal male and female subjects walking around a 60.5m-circular outdoor track. Subjects were divided into four age groups (children, 6-12 years; teens; young adults, 20-59 years; and senior adults, 60-80 years). Oxygen consumption was measured with a modified Douglas Bag technique during the fourth and fifth minutes of each trial. Standard tables according to age and sex were derived for the average energy expenditure (rate of oxygen uptake, energy cost per meter, and heart rate) and for the gait characteristics (speed, cadence, stride length) at the subjects' customary slow, normal, and fast walking speeds. Statistical analysis was performed to determine the energy-speed relationship for the different age groups to derive normative tables for the rate of oxygen uptake throughout the range of customary walking velocities.

Adolescent↗

A comparison of foot-switch and EMG analysis of varus deformities of the feet of children with cerebral palsy.

Fifty-one children with cerebral palsy who were candidates for surgery for equinovarus deformities of the foot had their gait evaluated by means of foot-switches and electromyography to determine the contribution of the anterior tibialis and posterior tibialis muscles to the deformity. Seven EMG patterns and five foot-switch patterns were identified, but there was no correlation between the EMG and foot-switch patterns. Foot-switch data alone could not identify the deforming muscles or their patterns, so are not adequate for planning surgical correction of varus feet of children with cerebral palsy.

Cerebral Palsy↗

In vivo oxidation of the methyl group of hepatic 5-methyltetrahydrofolate.

Methionine given parenterally to rats caused rapid disappearance of methyltetrahydrofolate from the liver and a corresponding rise in tetrahydrofolate and formyl-tetrahydrofolate concentrations. When [14C]H3--H4folate was given, methionine caused an increased [14C]0(2) excretion, indicating that oxidation of the methyl group had occurred. Methionine was more effective than S-adenosylmethionine at causing oxidation, but serine was ineffective. The lowest dose of methionine to produce an effect was 0.5 mumol, which is less than the daily dietary intake in a rat. The data suggest that the concentration of methylfolate in rat livers is controlled by the concentrations of methionine.

Adenosine↗

ACR-NEMA digital imaging and communications standards: minimum requirements.

The purposes, implications, and history of development of the American College of Radiology-National Electrical Manufacturers Association (ACR-NEMA) Digital Imaging and Communication Standard and its contents are briefly described, and the minimum requirements of the ACR-NEMA Digital Imaging and Communication Standard are described with a concise introduction of each layer. The usefulness, validity, current status, and future development of the standard are also discussed.

Computer Systems↗

Demyelination and decreased S-adenosylmethionine in 5,10-methylenetetrahydrofolate reductase deficiency.

We previously described demyelination in the brain and subacute combined degeneration of the spinal cord in a patient with 5,10-methylenetetrahydrofolate reductase deficiency. To assess the role of methionine, S-adenosylmethionine, folate, and neurotransmitter amine metabolism in the demyelination process, we measured these metabolites in CSF from this patient; the findings are compared with those obtained from three patients in whom neurologic deterioration had been halted by the administration of betaine. Folate concentrations were low, and amine and biopterin metabolism were abnormal in all patients. Methionine and S-adenosylmethionine concentrations were undetectable in the first patient. In those receiving betaine, methionine concentrations were proportional to the dose administered and S-adenosylmethionine concentrations were near normal. The results provide the first evidence for an association between defective S-adenosylmethionine metabolism and demyelination in humans.

5,10-Methylenetetrahydrofolate Reductase (FADH2)↗

Functional comparison of posterior cruciate-retained versus cruciate-sacrificed total knee arthroplasty.

Gait of 11 patients with bilateral paired posterior cruciate-retaining and cruciate-sacrificing total knee arthroplasties (TKA) was studied preoperatively and two years postoperatively on walking and stair climbing. Five-year clinical and roentgenographic examinations were included in the study. Differences between the two prostheses were noted both in level walking and in stair climbing. On level walking, cruciate-sacrificed TKA had more flexion in loading response and increased flexion and varus moments with increased muscle activity of quadriceps and biceps femoris. Abnormal gaits common to both types of knee were decreased flexion in stance and decreased single-limb stance. Both knees had a stiff-legged gait during stance. On stairs, the cruciate-sacrificed TKA substituted soleus muscle activity for knee stability. The single-limb stance and range of motion were similar for both knees. In clinical terms, the cruciate-sacrificed TKA is less efficient and has greater medial loading and higher joint reaction forces that may affect durability of the prosthesis. The five-year knee scores, patient satisfaction, and roentgenographic examinations were equal for both sets of knees.

Adult↗

Informal communication networks and change in physicians' practice behavior.

This study used influential physicians to disseminate information concerning the advantages of developing and using computer-stored personal order sets with a hospital information system. The results indicate that continuing medical education delivered through influential physicians is an effective way of changing physicians' practice behavior.

Communication↗

Tomorrow's nurses.

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Career Choice↗