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Biomedical subjects

J Naughton

Publications and source records attributed to J Naughton.

At least 19 recordsLinked to original sources
PubMed2001

Prognostic value of peak exercise systolic blood pressure on long-term survival after myocardial infarction.

This study examined the association between peak exercise systolic blood pressure and other exercise test parameters and the long-term (19-year) survival of 625 patients with myocardial infarction who were original participants of the National Exercise and Heart Disease Project, a 3-year (1976 to 1979) multicenter randomized exercise clinical trial. Results show that low peak exercise systolic blood pressure (< or =140 mm Hg) was associated with increased mortality throughout the 19 years of follow-up, and men with this finding obtained no survival benefit from participating in an exercise program.

Adult↗
PubMed2001

Correlates of compliance in a randomized exercise trial in myocardial infarction patients.

PURPOSE: Exercise-based rehabilitation programs have been associated with decreased morbidity and mortality after myocardial infarction. Unfortunately, attendance is often poor, and information is limited regarding predictors of long-term compliance to such programs. This study examined factors associated with exercise session compliance over 3 yr in male myocardial infarction (MI) survivors. METHODS: Subjects were participants in the National Exercise and Heart Disease Project, a 3-yr (1976-1979) multicenter, randomized clinical trial (N = 651); 308 men, 30-64 yr of age, were randomized to the exercise treatment group, that met three times/week throughout the study. Compliance was defined as the number of sessions attended/number of sessions conducted. Patient characteristics at enrollment were considered as possible predictors of compliance. RESULTS: Compliance decreased as time since enrollment increased with the largest decrease observed after the first 8 wk. Compliance correlated positively with exercise test measures [last completed stage (r = 0.17, P < 0.01), peak heart rate (r = 0.11, P = 0.06)], high density lipoprotein (HDL) cholesterol (r = 0.15, P = 0.10), age (r = 0.11, P = 0.07), and inversely with body mass index (r = -0.19, P = 0.001), sum of three skinfolds (r = -0.15, P < 0.01), total cholesterol (r = -0.18, P < 0.01), triglycerides (r = -0.16, P < 0.01), and depression (r = -0.09, P < 0.11). Current smokers were less compliant than former and nonsmokers (r = -0.21, P < 0.001). The correlations with last completed stage, BMI, skinfolds, total cholesterol, and smoking status were statistically significant. The model explained 22.2% of the variance in compliance (r2 = 0.222). Baseline work capacity was among the most consistent predictors of early and late compliance. CONCLUSION: Compliance decreased over time. Men already at high risk for repeat events due to elevated risk factors were less compliant. These findings have important clinical implications regarding screening, intervention, and participation in potential cardiac rehabilitation program dropouts.

Adult↗
PubMed2000

Maximal exercise systolic pressure, exercise training, and mortality in myocardial infarction patients.

The relation of maximal exercise systolic pressure to physical conditioning and to mortality was determined in 641 men with > or =1 myocardial infarctions. Each performed a standardized multistage exercise test before randomized assignment either to an exercise group or a control group and at scheduled periodic intervals over 3 years. This study compares 123 men with maximal exercise systolic pressures (MESP) of < or =140 mm Hg with 518 men whose maximal exercise systolic pressure was > or =140 mm Hg. At baseline, the 2 groups were comparable for age, entry time since the occurrence of the qualifying cardiac event, and reported use of antihypertensive medications. Men with low MESP used more beta blockers, had lower systolic pressure measurements at rest and by definition at maximal exercise, and lower work capacity than men with higher levels of MESP. Men with low MESP experienced: (1) no reduction in mortality with exercise conditioning (p<0.86), and (2) a significantly higher mortality rate over 3 years (p<0.003) compared with men with higher levels of MESP. The relation of a low MESP to mortality persisted: (1) whether MESP or work capacity increased from the baseline exercise test to the last performed exercise test, and (2) whether it was measured at low (<6 METs) or high (> or =6 METs) levels of work capacity. We conclude that low maximal exercise systolic blood pressure is a predictor of mortality and is associated with an ineffective training response in men with myocardial infarction.

Blood Pressure↗
PubMed2000

TVB receptors for cytopathic and noncytopathic subgroups of avian leukosis viruses are functional death receptors.

The identification of TVB(S3), a cellular receptor for the cytopathic subgroups B and D of avian leukosis virus (ALV-B and ALV-D), as a tumor necrosis factor receptor-related death receptor with a cytoplasmic death domain, provides a compelling argument that viral Env-receptor interactions are linked to cell death (4). However, other TVB proteins have been described that appear to have similar death domains but are cellular receptors for the noncytopathic subgroup E of ALV (ALV-E): TVB(T), a turkey subgroup E-specific ALV receptor, and TVB(S1), a chicken receptor for subgroups B, D, and E ALV. To begin to understand the role of TVB receptors in the cytopathic effects associated with infection by specific ALV subgroups, we asked whether binding of a soluble ALV-E surface envelope protein (SU) to its receptor can lead to cell death. Here we report that ALV-E SU-receptor interactions can induce apoptosis in quail or turkey cells. We also show directly that TVB(S1) and TVB(T) are functional death receptors that can trigger cell death by apoptosis via a mechanism involving their cytoplasmic death domains and activation of the caspase pathway. These data demonstrate that ALV-B and ALV-E use functional death receptors to enter cells, and it remains to be determined why only subgroups B and D viral infections lead specifically to cell death.

Animals↗
PubMed1999

Results of a multicenter randomized clinical trial of exercise and long-term survival in myocardial infarction patients: the National Exercise and Heart Disease Project (NEHDP).

BACKGROUND: This study examined whether a supervised exercise program improved 19-year survival in 30- to 64-year-old male myocardial infarction patients. METHODS AND RESULTS: The men (n=651) were participants in the National Exercise and Heart Disease Project, a 3-year multicenter randomized clinical trial conducted in the United States (1976-1979). The treatment group (n=315) exercised for 8 weeks in a laboratory. Thereafter, they jogged, cycled, or swam in a gymnasium/pool setting guided by an individualized target heart rate. Participants in the control group (n=319) were to maintain normal routines but not participate in any regular exercise program. Participants were followed up until their death or December 31, 1995. Cox proportional hazards analysis revealed the all-cause mortality risk estimates (95% CIs) in the exercise group compared with controls to be 0.69 (0.39 to 1.25) after an average follow-up of 3 years, 0.84 (0.55 to 1.28) after 5 years, 0.95 (0.71 to 1.29) after 10 years, 1.02 (0.79 to 1.32) after 15 years, and 1.09 (0.87 to 1. 36) after 19 years. Cardiovascular disease (CVD) mortality risk estimates (95% CI) for the same follow-up periods were 0.73 (0.37 to 1.43), 0.98 (0.60 to 1.61), 1.21 (0.79 to 1.60), 1.14 (0.84 to 1.54), and 1.16 (0.88 to 1.52). However, each 1-MET increase in work capacity from baseline to the end of the original trial resulted in consistent reductions in all-cause and CVD mortality risk at each follow-up period, regardless of initial work-capacity level. CONCLUSIONS: These findings indicate exercise-program participation resulted in nonsignificantly reduced mortality risks early in the follow-up period. Benefits diminished as time since participation increased, which suggests that the protective mechanisms associated with the program may be short term. Contamination between groups over time could also explain the diminished effects, because increased work capacity provided survival benefits up to 19 years.

Adult↗
PubMed1999

Work and leisure time physical activity and mortality in men and women from a general population sample.

PURPOSE: The purpose of this study was to examine the long-term relationships between total physical activity and mortality from all causes and coronary heart disease (CHD) in the general population. METHODS: A prospective design was used, following participants for 29 years, beginning in 1960. The study population consisted of a randomly selected sample of white male (n = 698) and female (n = 763) residents of Buffalo, New York with a 79.0% participation rate and follow-up rates of 96.0% and 90.2% in males and females, respectively. At baseline, comprehensive information was obtained regarding participants' usual physical activity at work and during leisure time. RESULTS: As of December 31, 1989, three hundred and two (43.3%) men and 276 (41.0%) women died, 109 (15.6%) and 81 (10.6%) from CHD, respectively. In men, a significant interaction was found between activity and body mass index (BMI) for both outcomes. In women, a significant activity by age interaction was observed. In non-obese men (BMI<27.02), activity was inversely associated with all-cause [relative risk (RR) = 0.59; 95% confidence interval (CI), 0.39-0.89] and CHD mortality (RR = 0.39; 95% CI, 0.18-0.83), independent from the effects of age and education. No such associations were found in obese men and increased risks could not be ruled out. Among women, younger participants (age <60 years) had a significantly reduced risk of CHD death with increased activity (RR = 0.26; 95% CI, 0.07-0.99). No other significant associations were observed. CONCLUSIONS: Physical activity favorably influences mortality risks in non-obese men and younger women. Gender-specific factors should be considered for potential effect modification.

Adolescent↗
PubMed1998

The CAR1 gene encoding a cellular receptor specific for subgroup B and D avian leukosis viruses maps to the chicken tvb locus.

Host susceptibility to subgroup B, D, and E avian leukosis viruses (ALV) is determined by specific alleles of the chicken tvb locus. Recently, a chicken gene that encodes a cellular receptor, designated CAR1, specific for subgroups B and D ALV was cloned, and it was proposed that this gene was the s3 allele of tvb (J. Brojatsch, J. Naughton, M. M. Rolls, K. Zingler, and J. A. T. Young, Cell 87:845-855, 1996). We now report that in a backcross derived from an F1 (Jungle Fowl x White Leghorn [WL]) male mated with inbred WL females, the cloned ALV receptor gene cosegregated with two markers linked to tvb. The two markers used were a tvb(s1)-specific antigen recognized by the chicken R2 alloantiserum and restriction fragment length polymorphisms associated with the expressed sequence tag com152e. With all three markers, no crossovers were observed among 52 backcross progeny tested and LOD linkage scores of 15.7 were obtained. These data demonstrate that CAR1 is the subgroup B and D ALV susceptibility gene located at tvb(s3).

Animals↗
PubMed1997

Identification of a cellular receptor for subgroup E avian leukosis virus.

Genetic studies in chickens and receptor interference experiments have indicated that avian leukosis virus (ALV)-E may utilize a cellular receptor related to the receptor for ALV-B and ALV-D. Recently, we cloned CAR1, a tumor necrosis factor receptor (TNFR)-related protein, that serves as a cellular receptor for ALV-B and ALV-D. To determine whether the cellular receptor for ALV-E is a CAR1-like protein, a cDNA library was made from turkey embryo fibroblasts (TEFs), which are susceptible to ALV-E infection, but not to infection by ALV-B and ALV-D. The cDNA library was screened with a radioactively labeled CAR1 cDNA probe, and clones that hybridized with the probe were isolated. A 2.3-kb cDNA clone was identified that conferred susceptibility to ALV-E infection, but not to ALV-B infection, when expressed in transfected human 293 cells. The functional cDNA clone is predicted to encode a 368 amino acid protein with significant amino acid similarity to CAR1. Like CAR1, the TEF protein is predicted to have two extracellular TNFR-like cysteine-rich domains and a putative death domain similar to those of TNFR I and Fas. Flow cytometric analysis and immunoprecipitation experiments demonstrated specific binding between the TEF CAR1-related protein and an immunoadhesin composed of the surface (SU) envelope protein of subgroup E (RAV-0) virus fused to the constant region of a rabbit immunoglobulin. These two activities of the TEF CAR1-related protein, specific binding to ALV-E SU and permitting entry only of ALV-E, have unambiguously identified this protein as a cellular receptor specific for subgroup E ALV.

Alkaline Phosphatase↗
PubMed1996

CAR1, a TNFR-related protein, is a cellular receptor for cytopathic avian leukosis-sarcoma viruses and mediates apoptosis.

Viral envelope (Env)-receptor interactions have been implicated in the cell death associated with infection by subgroups B and D avian leukosis-sarcoma viruses (ALVs). A chicken protein, CAR1, was identified that permitted infection of mammalian cells by these viral subgroups. CAR1 bound to a viral Env fusion protein, comprising an ALV-B surface Env protein and the Fc region of an immunoglobulin, indicating that it is a specific viral receptor. CAR1 contains two extracellular cysteine-rich domains characteristic of the TNFR family and a cytoplasmic region strikingly similar to the death domain of TNFR1 and Fas, implicating this receptor in cell killing. Chicken embryo fibroblasts susceptible to ALV-B infection and transfected quail QT6 cells expressing CAR1 underwent apoptosis in response to the Env-Ig fusion protein, demonstrating that this cytopathic ALV receptor can mediate cell death.

3T3 Cells↗
PubMed1994

The academic health center and the healthy community.

US medical care reflects the priorities and influence of academic health centers. This paper describes the leadership role assumed by one academic health center, the State University at Buffalo's School of Medicine and Biomedical Sciences and its eight affiliated hospitals, to serve its region by promoting shared governance in educating graduate physicians and in influencing the cost and quality of patient care. Cooperation among hospitals, health insurance payers, the business community, state government, and physicians helped establish priorities to meet community needs and reduce duplication of resources and services; to train more primary care physicians; to introduce shared governance into rural health care delivery; to develop a regional management information system; and to implement health policy. This approach, spearheaded by an academic health center without walls, may serve as a model for other academic health centers as they adapt to health care reform.

Academic Medical Centers↗
PubMed1992

Exercise training for patients with coronary artery disease. Cardiac rehabilitation revisited.

Medically prescribed and supervised physical activity forms the keystone for cardiac rehabilitation. A patient's potential and limitations for successful participation in an active restoration programme are determined by the degree of symptomatic recovery and physiological adaptations to a standardised, multistage exercise test. Confirmation of the effects of physical activity intervention is measured by the performance of the same exercise test under near identical conditions at periodic intervals. The prescribed physical activity regimen is usually performed minimally 3 times per week in sessions which last from 30 to 60 minutes. The object is to utilise from 100 to 200 kcal per exercise session. The demonstrated benefits of regular physical activity include reduction of the systolic blood pressure and heart rate at supine rest and while performing submaximal work, an increased level of physical work capacity, reduction in the myocardial oxygen cost at rest and during performance of submaximal exercise, reduction in percentage body fat with a concomitant increase in muscle mass, and reduction in plasma triglycerides. Regular physical activity, in and of itself, does not effect a reduction in plasma cholesterol or an increase in high density lipoprotein cholesterol, nor does it affect such lifestyle habits as cigarette smoking and alcohol consumption. While contraindications to performing medically prescribed and supervised physical activity are usually restricted to the physically incapacitated patient, failure to achieve an exercise threshold for systolic blood pressure of 140mm Hg or higher is probably a contraindication. This conclusion is based on findings which indicate that treated and control patients with this physiological limitation experience the same mortality rates over 3 years. Regularly performed physical activity by coronary artery diseased patients is associated with reductions in mortality from all cardiovascular causes except sudden death. This intervention does not effect morbidity. Although the scientific evidence warrants the prudent use of physical activity for coronary artery disease patients, the case for its long term benefits remains to be proved.

Coronary Disease↗
PubMed1988

Butter-enriched diets reduce arterial prostacyclin production in rats.

Rats were fed diets containing 10%, 30% or 50% energy as fat derived predominantly from butter or lard. The protein content of the diets was maintained at 20%. After three weeks on the diets, the rats were killed and the following parameters measured: prostacyclin production in vitro from abdominal aorta and mesenteric artery; platelet aggregation to ADP and thrombin; fatty acid composition of the phospholipids in plasma, thoracic aorta and liver; smooth muscle reactivity and release of endothelial derived relaxing factor (EDRF) from aortic endothelium stimulated by acetylcholine. There was no significant effect of increasing fat content of the diets (neither lard nor butter) on platelet aggregation. In contrast, prostacyclin production in both the mesenteric artery and the abdominal aorta fell in a concentration-dependent manner in the butter-supplemented rats. However, no effect on prostacyclin production was detected in arteries from the lard-supplemented animals. The effects of the diets on prostacyclin (PGI2) production correlated very well with the changes in plasma, aortic and liver phospholipid arachidonic acid (AA) and eicosapentaenoic acid (EPA) contents. AA decreased in a concentration-dependent manner in the rats fed the butter-enriched diets but did not change in those fed the lard-enriched diets, whereas EPA rose in a concentration-dependent manner in the butter-fed rats and was unchanged in the lard-fed animals. The clear-cut effects of the butter-enriched diets on aortic phospholipid fatty acid composition and aortic PGI2 production were accompanied by a significant reduction in smooth muscle relaxation to EDRF.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Role of physical activity as a secondary intervention for healed myocardial infarction.

Five exercise clinical trials were conducted to determine the effectiveness of physical activity on selected outcomes, especially mortality and morbidity rates, in patients recovered from myocardial infarction. Although the design of every trial differed, each evaluated the effects of medically prescribed and supervised regular physical activity. In 3 studies there were substantially lower mortality rates in the exercise patients compared with control patients, but statistically significant differences occurred in only 1 of the 3 trials. No differences between treated and control patients were observed in another trial. In the fifth trial, a slight excess mortality rate was reported for the treatment group. However, both groups in this trial were assigned to an exercise regimen in which only the frequency of attendance and intensity of regimen differed. Although regular physical activity tended to reduce mortality rates in the first 3 trials, it is apparent that it did not affect recurrence rates of nonfatal myocardial infarction. In fact, this condition generally occurred more frequently in treated than in control patients. It is clear that more clinical investigations are required before a definitive statement confirming the effectiveness of regular physical activity as a secondary intervention for myocardial infarction can be made.

Clinical Trials as Topic↗
PubMed1984

Effect of left ventricular aneurysmectomy on exercise performance.

We performed pre- and post-operative exercise testing on 12 patients with coronary artery bypass surgery and ventricular aneurysmectomy and 2 patients with ventricular aneurysmectomy alone. Most patients showed better exercise performance, higher double product, better work capacity and were able to exercise longer. Two patients who had ventricular aneurysmectomy alone showed similar changes. Most patients showed improved New York Heart Association functional classification and exercise performance after surgery.

Adult↗
PubMed1984

Contributions of exercise clinical trials to cardiac rehabilitation.

Even though the case for the use of physical activity has not been fully established, it is apparent from the clinical trials conducted so far that there are sufficient reasons to recommend it to selected, motivated patients. Further well-designed scientific studies of physical activity in patients with coronary heart disease are needed to clarify the unanswered questions regarding its use in cardiac rehabilitation.

Adult↗