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Biomedical subjects

H Lew

Publications and source records attributed to H Lew.

51 records · Page 3Linked to original sources
PubMed1989

Cost-benefit analysis of early return to work after uncomplicated acute myocardial infarction.

The economic consequences of an Occupational Work Evaluation designed to identify low risk patients recovering from uncomplicated acute myocardial infarction (AMI) and hasten their return to work was evaluated in a randomized trial. Two hundred one employed, clinically low risk men recovering from AMI were randomized to undergo an intervention (intervention group, 99 patients) consisting of an Occupational Work Evaluation or to receive usual care (usual care group, 102 patients). The time to return to work was reduced from 75 days in usual care patients to 51 days in intervention patients (p less than 0.002). Significant differences were found between groups for medical costs and occupational income during follow-up. Total medical costs per patient were lower in the intervention patients than in the usual care patients in the 6 months after AMI ($2,970 vs $3,472). Occupational income per patient was higher in intervention patients than in the usual care group in the 6 months after AMI ($9,655 vs $7,553). The per capita benefit accounting for medical costs and occupational income was $6,685 for intervention patients and $4,081 for usual care patients. Projected to the greater than 300,000 low risk, employed survivors of AMI annually in this country, the savings generated by the Occupational Work Evaluation could yield an annual economic benefit greater than 800 million dollars.

Algorithms↗
PubMed1986

Severe depletion in liver glutathione during physical exercise.

Physical exercise at submaximal levels in rats results in a progressive depletion of liver glutathione to about 20% of the levels found in sedentary controls which persists for several hours following the cessation of exercise. Skeletal muscle appears to be spared this severe depletion phenomenon. The levels of plasma glutathione show a transient increase at the beginning of the exercise bout followed by a linear decrease with increased running time of the animals. These results may be particularly relevant when attempting to understand the effects of physical exercise on a large number of cellular and organismal functions that are known or suspected to depend critically on the glutathione status of the liver.

Animals↗
PubMed1985

Changes in the glutathione status of plasma, liver and muscle following exhaustive exercise in rats.

Our results show that following physical exercise to exhaustion, the levels of reduced glutathione are increased in the plasma, but decreased in both the liver and skeletal muscle of rats. Levels of glutathione disulfide are increased in all 3 tissues. Our results are consistent with a mechanism in which the liver may be dumping reduced glutathione into the plasma in an attempt to deliver it to those tissues that need it the most: in this case, skeletal muscle.

Animals↗
PubMed1985

Medically directed at-home rehabilitation soon after clinically uncomplicated acute myocardial infarction: a new model for patient care.

Medically directed at-home rehabilitation was compared with group rehabilitation which began 3 weeks after clinically uncomplicated acute myocardial infarction (AMI) in 127 men, mean age 53 +/- 7 years. Between 3 and 26 weeks after AMI, adherence to individually prescribed exercise was equally high (at least 71%), the increase in functional capacity equally large (1.8 +/- 1.0 METs) and nonfatal reinfarction and dropout rates equally low (both 3% or less) in the 66 men randomized to home training and the 61 men randomized to group training. No training-related complications occurred in either group. The low rate of reinfarction and death (5% and 1%, respectively) in the study as a whole, which included 34 patients with no training and 37 control patients, reflected a stepwise process of clinical evaluation, exercise testing at 3 weeks and frequent telephone surveillance of patients who underwent exercise training. Medically directed at-home rehabilitation has the potential to increase the availability and to decrease the cost of rehabilitating low-risk survivors of AMI.

Adult↗
PubMed1984

Comparative value of maximal treadmill testing, exercise thallium myocardial perfusion scintigraphy and exercise radionuclide ventriculography for distinguishing high- and low-risk patients soon after acute myocardial infarction.

The prognostic value of symptom-limited treadmill exercise electrocardiography, exercise thallium myocardial perfusion scintigraphy and rest and exercise radionuclide ventriculography was compared in 117 men, aged 54 +/- 9 years, tested 3 weeks after a clinically uncomplicated acute myocardial infarction (MI). During a mean follow-up period of 11.6 months, 8 men experienced "hard" medical events (cardiac death, nonfatal ventricular fibrillation or recurrent MI) and 14 were hospitalized for unstable angina pectoris, congestive heart failure or coronary bypass surgery (total of 22 combined events). By multivariate analysis (Cox proportional hazards model), peak treadmill work load and the change in left ventricular ejection fraction (EF) during exercise were significant (p less than 0.01) predictors of hard medical events; these 2 risk factors and recurrent ischemic chest pain in the coronary care unit were also significantly predictive (p less than 0.001) for combined events. A peak treadmill work load of 4 METs or less or a decrease in EF of 5% or more below the value at rest during submaximal effort distinguished 22 high-risk patients (20% of the study population) from 89 low-risk patients. The rate of hard medical events within 12 months was 23% (5 of 22 patients), vs 2% (2 of 89 patients) in the high- and low-risk patient subsets, respectively (p less than 0.001). Thus, in patients who underwent evaluation 3 weeks after a clinically uncomplicated MI, exercise radionuclide ventriculography contributed independent prognostic information to that provided by symptom-limited treadmill testing and was superior to exercise thallium scintigraphy for this purpose.

Aged↗
PubMed1983

Stepwise risk stratification soon after acute myocardial infarction.

A stepwise rise stratification procedure sequentially combining historical and clinical characteristics and treadmill exercise test results was applied to 702 consecutive men aged less than or equal to 70 years who were alive 21 days after acute myocardial infarction (MI). Historical characteristics alone (prior MI and prior angina or recurrence of pain in the coronary care unit) identified 10% of patients with the highest rate of reinfarction and death within 6 months (18%). Clinical contraindications to exercise testing identified another 40% of patients with an intermediate rate of cardiac events (6.4%). In the 50% of patients who underwent treadmill testing 3 weeks after MI, the rate of cardiac events within 6 months was 4.4%: 3.9% in patients with a negative test and 9.7% in patients with a positive test (ischemic ST-segment depression greater than or equal to 0.2 mV and a peak heart rate less than or equal to 135 beats/min). Patients with negative treadmill tests, who comprised 46% of patients less than or equal to 70 years and 53% of patients less than or equal to 60 years, had a cardiac death rate of less than 2% in the 6 months after MI. The stepwise classification procedure correctly classified 72% of patients with hard medical events within 6 months. Thus, most patients who experience subsequent cardiac events are correctly classified on the basis of historical and clinical risk characteristics. In patients without these risk characteristics, early treadmill testing is useful for further discriminating high-risk from very low risk patients.

Aged↗
PubMed1978

Mummification of the infarcted myocardium by high dose corticosteroids.

There is evidence that glucocorticoids reduce infarct size but their use in myocardial infarction remains controversial because of their potential adverse effects on healing of the infarct. To investigate the healing process, rats received either four parenteral doses of 50 mg/kg of methylprednisolone (MP) or saline 5 min, 3,6 and 24 hr after coronary occlusion and their hearts were examined by light and electron microscopy 48 hr and seven days after occlusion. At 48 hr, in five untreated rats, only 12 +/- 7% of injured myocytes showed the persistence of striations and a relatively intact sarcolemma despite loss of nuclei and hence appeared "mummified" whereas in six MP-treated rats 72 +/- 8% of myocytes exhibited this appearance (P less than 0.001). In treated rats there were fewer phagocytes than in controls. At seven days, in seven MP-rats, mummified cells were still more prominent than in five untreated rats and there were fewer phagocytes and less collagen. In conclusion, high dose of MP delays the inflammatory process and retards the disintegration of necrotic myocytes, resulting in impaired healing.

Animals↗
PubMedDate not supplied

Effects of endurance training and exercise on tissue antioxidative capacity and acetaminophen detoxification.

Both acute acetaminophen toxicity and physical exercise are accompanied by structural and functional damage to tissues. For acute acetaminophen toxicity, this damage occurs mainly in the liver. This damage, which is believed to be initially caused by oxidation and/or arylation, occurs only after depletion of liver glutathione (GSH). GSH normally protects against oxidation and/or arylation. Prolonged physical exercise also depletes GSH in the body. We hypothesized that with endurance training (repeated oxidant stress) tissues will develop mechanisms to prevent GSH depletion. Our results show that, for the same amount of submaximal exercise, trained rats are able to maintain their levels of GSH or their GSH redox status (in the liver, heart, skeletal muscle and plasma) in contrast to their untrained counterparts. Also, upon administration of acetaminophen, trained rats show a less pronounced depletion in liver GSH than untrained rats. We also hypothesized that training may lead to improved maintenance of tissue GSH homeostasis because of induction in the enzyme pathways of protection. We observe that training significantly increases (50-70%) glutathione peroxidase and reductase, glucose-6-phosphate dehydrogenase, and catalase activity in heart and skeletal muscle. Since GSH, in addition to providing cellular protection, also functions in other physiological processes including transport and metabolism, the training-induced benefits seen here may have more far-reaching consequences than ever before realized.

Acetaminophen↗
PubMedDate not supplied

A morphological study of drill holes applied with mitomycin-C in hydroxyapatite orbital implants.

For maximum motility of the prosthesis, the hydroxyapatite orbital implant should be drilled and coupled to the prosthesis via a motility peg. However, problems of peg extrusion have been reported to occur in 25-30% of cases. In this animal study, serial histopathological changes within the drill hole after hydroxyapatite implantation were observed and the effect of mitomycin-C (MMC) was evaluated as a new method of hole maintenance. A hole was drilled into each hydroxyapatite implant 20 weeks after enucleation and different concentrations of MMC solution were applied. The morphological changes of the holes were evaluated with proliferating cell nuclear antigen. In the control group (non-MMC-treated), all the motility pegs were extruded showing occluded holes. In the groups treated with 0.5 and 1.0 mg/ ml MMC, all the motility pegs were maintained in position with the holes at ample depth and width. However, toxicity, such as conjunctival ulcer and implant exposure around the hole, was observed in the 1.0 mg/ml MMC group. A 0.5 mg/ml MMC application for 5 min to the drill hole effectively reduced the risk of peg extrusion in this albino rabbit model.

Animals↗
PubMedDate not supplied

Effect of botulinum toxin A chemodenervation in sensory strabismus.

PURPOSE: To study the effect of botulinum toxin type A chemodenervation in sensory strabismus. METHODS: Twelve patients with sensory strabismus were treated with an injection of botulinum toxin type A (Botox; Allergan, Irvine, Calif). Botulinum toxin type A was diluted with 0.9% sodium chloride without preservative at a dose that ranged from 1.25-5 U. A Teflon-coated needle electrode was inserted into the medial rectus muscle in cases of esotropia and into the lateral rectus muscle in cases of exotropia. Four patients were treated with > or =2 injections of botulinum toxin type A. Changes in the angle of strabismus and related complications were followed for >6 months postinjection. RESULTS: The mean deviation before injection was 33.8 prism diopters (delta) and the mean corrective effect on the deviation was 72.8% after injection in patients with sensory strabismus. The final deviation in 9 patients was <10 delta. Complications were hypertropia in 3 (25%) patients and conjunctival hemorrhage in 1 (8.3%) patient. CONCLUSION: Botulinum toxin type A is likely to prevent muscle contracture and affect muscle and neuronal tissues. This study on the effects of sensory strabismus with botulinum toxin type A injection suggests it has the potential to replace surgery or be used as an adjuvant therapy.

Adult↗