Biomedical subjects

Richard Seip

Publications and source records attributed to Richard Seip.

5 recordsLinked to original sources

PubMed2006

Resting and exercise energy use in Antarctica: effect of 50% restriction in temperate climate energy requirements.

OBJECTIVE: To determine the impact of energy restriction (ER) upon the previously reported increased resting and exercise-related oxygen utilization, reduced body temperature, increased serum TSH, and reduced serum free T3 concentrations found during Antarctic residence (AR). DESIGN: Prospective, intervention with both paired controls and a similar reference control group (RG). PATIENTS AND MEASUREMENTS: Seven subjects were assessed before and after a 50% ER period of 60 h. This ER was carried out within 30 days of arriving in Antarctica in October (OCT) and again after 10 months AR in August (AUG). During the periods of ER, mean energy consumption was 5662 +/- 1344 kJ/day in OCT and 5529 +/- 967 kJ/day in AUG. Resting metabolic rate (RMR), a calculated resting metabolic rate (RMR(reg)) using a submaximal work regression, serum TSH, FT3 and tympanic temperature (Tty) were measured. These values were compared with a similar RG of 12 subjects reported previously who were studied in California, USA before and then again during AR. RESULTS: Weight declined by 1.1 +/- 0.1 kg/day (OCT) and 0.92 +/- 0.2 kg/day (AUG) with ER, resulting in a reduction of body weight by 3.1 +/- 0.4% in OCT (P = 0.0001) and 2.5 +/- 0.4% in AUG (P = 0.0015) during AR. The RMR before ER did not change with AR and it was not significantly different from the RG studied in California. With ER the RMR tended to decline in both OCT (132 +/- 5 to 122 +/- 4 mlO2/min/m2) and AUG (134 +/- 5 to 126 +/- 5 mlO2/min/m2), but these were not significant. By contrast, RMR(reg) obtained before ER was increased with AR by 22.5 +/- 7.8% (P = 0.01) in OCT and by 28.1 +/- 7.0% (P = 0.0008) in AUG over the RG values obtained in California. RMR(reg) did not decrease with ER in either OCT or AUG. The total energy expenditure derived from these measures of weight loss suggests that 24-h energy requirements are 74.4%[95% confidence interval (CI) 2.6-146.3; P < 0.05] more than those expected in temperate climates. Tty declined by 0.6 +/- 0.2 degrees C (P < 0.01) with AR compared with the RG measured in California, but was not affected by either period of ER. ER had no effect on FT3 but tended to decrease serum TSH in AUG (P = 0.06). CONCLUSIONS: Exercise-related energy requirements are increased with AR. Moderate ER may reduce resting but not exercise-related energy expenditure and it is associated with a weight loss exceeding expectations for 50% restriction of temperate climate energy predictions.

Acclimatization↗

PubMed2005

Physiogenomic analysis links serum creatine kinase activities during statin therapy to vascular smooth muscle homeostasis.

Statins are highly effective at reducing coronary disease risk. The main side effects of these medications are a variety of skeletal muscle complaints ranging from mild myalgia to frank rhabdomyolysis. To search for physiologic factors possibly influencing statin muscle toxicity, we screened for genetic associations with serum creatine kinase (CK) levels in 102 patients receiving statin therapy for hypercholesteremia. A total of 19 single nucleotide polymorphism (SNPs) were selected from ten candidate genes involved in vascular homeostasis. Multiple linear regression was used to rank the SNPs according to probability of association, and the most significant associations were analyzed in greater detail. SNPs in the angiotensin II Type 1 receptor (AGTR1) and nitric oxide synthase 3 (NOS3) genes were significantly associated with CK activity. These results demonstrate a strong association between CK activity during statin treatment and variability in genes related to vascular function, and suggest that vascular smooth muscle function may contribute to the muscle side effects of statins.

Adult↗

PubMed2004

Effectiveness of ezetimibe in clinical practice.

We retrospectively evaluated the effect of ezetimibe in a population of patients with hypercholesterolemia referred to a lipid clinic. Ezetimibe decreased low-density lipoprotein cholesterol by 22% in all patients treated with this medication (n = 87). Ezetimibe was also effective in patients treated with this agent alone (-23%, n = 21), with a statin (-23%, n = 28), with a nonstatin (-21%, n = 18), and with both a statin and a nonstatin (-22%, n = 20).

Aged↗

PubMed2004

Functional polymorphisms associated with human muscle size and strength.

INTRODUCTION: Skeletal muscle is critically important to human performance and health, but little is known of the genetic factors influencing muscle size, strength, and its response to exercise training. The Functional single nucleotide polymorphisms (SNP) Associated with Muscle Size and Strength, or FAMuSS, Study is a multicenter, NIH-funded program to examine the influence of gene polymorphisms on skeletal muscle size and strength before and after resistance exercise training. METHODS: One thousand men and women, age 18 - 40 yr, will train their nondominant arm for 12 wk. Skeletal muscle size (magnetic resonance imaging) and isometric and dynamic strength will be measured before and after training. Individuals whose baseline values or response to training deviate > or = 1.5 SD will be defined as outliers and examined for genetic variants. Initially candidate genes previously associated with muscle performance will be examined, but the study will ultimately attempt to identify genes associated with muscle performance. CONCLUSION: FAMuSS should help identify genetic factors associated with muscle performance and the response to exercise training. Such insight should contribute to our ability to predict the individual response to exercise training but may also contribute to understanding better muscle physiology, to identifying individuals who are susceptible to muscle loss with environmental challenge, and to developing pharmacologic agents capable of preserving muscle size and function.

Adolescent↗

PubMed2003

Circulating resistin levels are not associated with obesity or insulin resistance in humans and are not regulated by fasting or leptin administration: cross-sectional and interventional studies in normal, insulin-resistant, and diabetic subjects.

Resistin is a novel adipocyte-secreted hormone proposed to link obesity with diabetes. Studies in mice have revealed conflicting data however, and the physiological role of circulating resistin in humans remains unknown. We conducted cross-sectional studies in 123 middle-aged women and 120 healthy young subjects and found that serum resistin levels did not correlate with markers of adiposity, including body mass index, waist-to-hip ratio, or fat mass, or insulin resistance assessed by homeostasis model, lipid profile, or serum leptin levels; but females had higher resistin levels than males (P < 0.02). We also found no difference in serum resistin levels between lean healthy and obese insulin-resistant nondiabetic and type 2 diabetic adolescents. Finally, to evaluate the effect of food deprivation and/or leptin administration on resistin levels, we performed interventional studies that revealed no significant difference in resistin levels after 48 h of fasting and/or leptin administration at either physiological or pharmacological doses. We conclude that circulating resistin is unlikely to play a major role in insulin resistance or energy homeostasis in humans.

Adolescent↗