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Biomedical subjects

G R Lesmes

Publications and source records attributed to G R Lesmes.

9 recordsLinked to original sources
PubMed1992

Passive smoking: the medical and economic issues.

Since the late 1970s, the dangers associated with passive (involuntary) smoking have been widely debated. While research throughout the world has produced findings showing sidestream smoke to be harmful and possibly deadly to nonsmokers, an equal number of studies have indicated that the harms have been overstated or misclassified or that they are nonexistent. Those debates have culminated in a report sponsored by the Environmental Protection Agency and other federal agencies. The report concludes that second-hand cigarette smoke kills 53,000 nonsmokers a year and is a major cause of indoor air pollution. This article identifies the major medical and economic issues in the debate on side-stream smoke. It affirms the federal government's position on the need to create more smoke-free environments and impose stronger smoking restrictions nationwide.

Age Factors↗
PubMed1992

Corporate healthcare costs and smoke-free environments.

Results from two studies were combined to assess potential market impact for programs to reduce health risks, as well as to define how small businesses can better control their healthcare operating expenses, widen their profit margins, and increase their productivity. The most effective solutions resulted from partnerships among the medical, business, and patient communities for the joint implementation of intensive smoking-cessation programs. In the first study, the chief executive officers of 1,100 small businesses in the Chicago area were polled regarding their opinions on healthcare costs. During the 4-year study period, 1986-1990, we observed a significant increase in their recognition of the impact of employee smoking on rising healthcare costs. From this study we identified three profile attributes of small-business leaders. First, these leaders possess a weak knowledge base regarding healthcare cost-containment methods; second, they understand the magnitude of the impact-rising healthcare costs have on corporate profitability; and third, they have a strong level of confidence (85%) that lifestyle modification programs for their employees, such as smoking cessation, can help control healthcare costs. In the second study we found that smoking-cessation programs with physician involvement, addiction assessment and treatment, and behavioral training and follow-up are preferred by those who want to stop smoking. Such programs have also enjoyed the highest level of sustained success.

Efficiency↗
PubMed1988

Serum creatine kinase and lactate dehydrogenase changes following an eighty kilometer race. Relationship to lipid peroxidation.

Pre and post race serum malondialdehyde (MDA), creatine kinase (CK) and lactate dehydrogenase (LDH) levels were studied in runners following an 80 km (50 mile) race. MDA is an indicator of lipid peroxidation. Subjects averaged 47.4 years (range 35-60), had a mean maximal oxygen uptake (VO2max) of 48.2 ml/kg, and averaged 121 km (75 miles) per week in training. Throughout the race, runners maintained a pace approximating 72% of VO2max. Previous data from our laboratory indicated a high correlation between resting MDA and total CK and CK-MB. Present resting data confirms prior results (r = 0.84 and 0.69 respectively). In addition, the relationship established at rest persisted following exercise (r = 0.62 and 0.85 respectively). Post race CK, CK-MB, LDH and MDA values for all subjects were significantly greater than resting values (p less than 0.01). Mean post CK and CK-MB levels were nearly 10 and 4 times lower, respectively, than prior values from our laboratory in subjects following a 100 km (62 mile) race. It was concluded that post exercise serum enzyme elevations, universally accepted as a marker of tissue damage, correlate well and may be related to an exercise induced lipid peroxidation.

Creatine Kinase↗
PubMed1979

Adaptations in skeletal muscle following strength training.

Five men were studied before and after 7 wk of isokinetic strength training to determine its effects on muscle enzyme activities and fiber composition. One of the subject's legs was trained using 10 repeated 6-s maximal work bouts, while the other leg performed repeated 30-s maximal knee extension exercise. The total work accomplished by each leg was constant. Training 4 times/wk achieved similar gains in peak torque for both legs at the training velocity (3.14 rad/s) and at slower speeds. Fatigability of the knee extensor muscles, as measured by a 60-s exercise test, was similar in both legs after training. Biopsy specimens showed significant changes in the % of the muscle area composed of type I and IIa fibers as a result of both strength training programs. In terms of muscle enzymes, only the 30 s exercise program resulted in elevated glycolytic, ATP-CP and mitochondrial activities. Despite these changes, none of the parameters measured were found to be related to the gains in either muscle strength or fatigability during maximal isokinetic contractions.

Adaptation, Physiological↗
PubMed1979

Leg extension power and muscle fiber composition.

The purpose of this investigation was to relate muscle fiber composition to the isokinetic measure of peak torque production through a range of leg extension velocities. Twenty-one males were biopsied from the vastus lateralis muscle to determine their percent distribution of slow twitch (%ST) and fast twitch (%FT) muscle fibers as identified through myofibrillar adenosine triphosphatase activity. All subjects showed a decline in peak torque with increasing velocities. Subjects with predominantly FT fibers were able to generate 11, 16, 23 and 47 percent greater relative peak torque than could predominantly ST subjects at lever arm velocities of 115, 200, 287 and 400 degrees/second respectively. Likewise the correlation between relative torque production and % FT were significant (p less than .05) and increased from r = 0.44 to r = 0.75 as velocity increased from 115 to 400 degrees/second respectively. These data suggest that muscle fiber composition becomes increasingly more related to power performance as the velocity of movement increases.

Adenosine Triphosphatases↗
PubMed1978

Metabolic responses of females to high intensity interval training of different frequencies.

The purpose of this investigation was to examine the effects of frequency and distance of high intensity, interval training on females. Thirty-two females participated in an eight-week program of interval run training. Subjects were assigned to either a 2 day/week or a 4 day/week group, as well as a high intensity, short distance (50,101,201 meters), or high intensity longer distance (604, 805, 1208 meters) group. Estimates of training intensity were 170% and 130% Vo2max for the short and longer distance groups, respectively. Maximal and submaximal measures of oxygen consumption (Vo2), heart rate (HR), and venous blood lactic acid were determined prior to and following the training program. After training, there was a significant increase (P less than 0.01) in Vo2max (13%) (deltax = 0.32 1/min or 5.2 ml/kg.min). Maximal VE increased approximately 12% after training (P less than 0.01). Max HR, max lactic acid, and submax Vo2 were not altered by the training. However, HR submax decreased significantly (P less than .05) after training by approximately 6%. Analysis of coveriance indicated that these changes were independent of training frequency, distance, and intensity. It was concluded that the changes in aerobic power and submaximal HR of females are independent of frequency, distance, and intensity of high-intensity interval training programs.

Adult↗
PubMed1978

Muscle strength and power changes during maximal isokinetic training.

This study investigated the effects of short duration, high intensity training on skeletal muscle. The extensors and flexors of the knee were tested and exercised by means of an isokinetic dynamometer. Measurements of peak torque were obtained at velocities ranging from 0 degrees/sec (isometric) to 300 degrees/sec through a distance of 90 degrees. Total work output was measured during repeated knee extensions and flexions for work tasks of 6 sec and 30 sec duration. A 1-min test of repeated maximal contractions was administered to examine muscular fatiguability before and after training. The subjects trained one leg with repeated 6 sec exercise bouts, while the other leg was trained using repeated 30 sec bouts. All training and testing was executed at near maximal force and at a constant velocity (180 degrees/sec). The subjects trained four times per week for a period of seven weeks. The daily work output was equal for the 6 and 30 sec training legs. Results indicate that: (1) isokinetic training programs of 6 and 30 seconds duration can significantly (P less than .05) increase peak muscular torque; (2) training velocity may be an important consideration in improving peak torque; (3) total work output was increased an average of 30% with either training at relatively slow (60 degrees/sec) or fast (180 degrees/sec) velocities; (4) both training programs significantly reduced the fatiguability of the knee extensor muscles.

Adult↗
PubMed1976

Metabolic and cardiovascular adjustment to work in air and water at 18, 25, and 33 degrees C.

By use of successive increments of discontinuous work with an arm-leg cycle ergometer the VO2, Q, SV, and HR were studied in six male subjects at rest and during exercise in air and in water at 18, 25, and 33 degrees C. The Q values obtained by CO2 rebreathing were reproducible. VO2 was linearly related to work with the plots for air and 33 degrees C water being similar. However, during work in 25 and 18 degrees C water, the VO2 averaged 9.0% (150 ml) and 25.3% (400 ml) higher, respectively, than values observed in 33 degrees C water, with the largest differences observed in leaner subjects. The plot of HR-VO2 was linear and almost identical during work in air and 33 degrees C water, but shifted significantly to the right in cooler water. VO2 averaged 250-700 ml higher in cold water compared to air and 33 degrees C water at a given mean heart rate. The Q vs. VO2 line was similar during work in air and in water with no effect of water or temperature. At similar levels of VO2, SV was significantly larger (P less than 0.05) in 25 and 18 degrees C water than in air or 33 degrees C water. Consequently, the reduction in heart rate during work in cold water was entirely compensated for by a proportionate increase in the SV of the heart. Q was therefore maintained at similar levels of energy expenditure in air and in 18, 25, and 30 degrees C water.

Acclimatization↗