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Biomedical subjects

Paul D Thompson

Publications and source records attributed to Paul D Thompson.

At least 19 recordsLinked to original sources
PubMed2007

Dietary calcium intake and renin angiotensin system polymorphisms alter the blood pressure response to aerobic exercise: a randomized control design.

BACKGROUND: Dietary calcium intake and the renin angiotensin system (RAS) regulate blood pressure (BP) by modulating calcium homeostasis. Despite similar BP regulatory effects, the influence of dietary calcium intake alone and combined with RAS polymorphisms on the BP response following acute aerobic exercise (i.e., postexercise hypotension) has not been studied. Thus, we examined the effect of dietary calcium intake and selected RAS polymorphisms on postexercise hypotension. METHODS: Subjects were men (n = 50, 43.8 +/- 1.3 yr) with high BP (145.3 +/- 1.5/85.9 +/- 1.1 mm Hg). They completed three experiments: non-exercise control and two cycle bouts at 40% and 60% of maximal oxygen consumption (VO2max). Subjects provided 3 d food records on five protocol-specific occasions. Dietary calcium intake was averaged and categorized as low (<880 mg/d = LowCa) or high (> or = 880 mg/d = HighCa). RAS polymorphisms (angiotensin converting enzyme insertion/deletion, ACE I/D; angiotensin II type 1 receptor, AT1R A/C) were analyzed with molecular methods. Genotypes were reduced from three to two: ACE II/ID and ACE DD; or AT1R AA and AT1R CC/AC. Repeated measure ANCOVA tested if BP differed among experiments, dietary calcium intake level and RAS polymorphisms. RESULTS: Systolic BP (SBP) decreased 6 mm Hg after 40% and 60% VO2max compared to non-exercise control for 10 h with LowCa (p < 0.01), but not with HighCa (p > or = 0.05). Under these conditions, diastolic BP (DBP) did not differ between dietary calcium intake levels (p > or = 0.05). With LowCa, SBP decreased after 60% VO2max versus non-exercise control for 10 h among ACE II/ID (6 mm Hg) and AT1R AA (8 mm Hg); and by 8 mm Hg after 40% VO2max among ACE DD and AT1R CC/CA (p < 0.01). With HighCa, SBP (8 mm Hg) and DBP (4 mm Hg) decreased after 60% VO2max compared to non-exercise control for 10 h (p < 0.05), but not after 40% VO2max (p > or = 0.05). CONCLUSION: SBP decreased after exercise compared to non-exercise control among men with low but not high dietary calcium intake. Dietary calcium intake interacted with the ACE I/D and AT1R A/C polymorphisms to further modulate postexercise hypotension. Interactions among dietary calcium intake, exercise intensity and RAS polymorphisms account for some of the variability in the BP response to exercise.

Journal Article↗
PubMed2007

Phytosterols and vascular disease.

PURPOSE OF REVIEW: Phytosterols and stanols are plant derivatives that compete with cholesterol for intestinal absorption and thereby lower serum cholesterol concentrations. They have been developed as food additives to help lower serum cholesterol but there is concern that these additives could inadvertently increase cardiovascular risk. This concern arises from the observation that patients with the rare genetic condition phytosterolemia overabsorb phytosterols and develop premature atherosclerosis. This review evaluates the relationship between phytosterol and stanol supplementation and cardiovascular risk. RECENT FINDINGS: Plant sterol supplementation produces minimal increases in blood phytosterol concentrations in humans. Recent animal studies suggest that phytosterols reduce atherosclerosis in the Apo-E deficient mouse model. The evidence from human studies is mixed and does not prove or disprove an increase in atherosclerotic risk from serum phytosterol levels. An increase in risk seems unlikely, but additional studies should address this possibility. SUMMARY: Phytosterols are effective in lowering low-density lipoprotein-cholesterol levels, and do not appear to increase atherosclerotic risk, but additional research on this topic is necessary.

Animals↗
PubMed2006

Urban ethnic minority women's attendance at health clinic vs. church based exercise programs.

Older, sedentary, urban-living, ethnic minority women are at high risk for preventable disease, but it is difficult to engage this population in health promotion efforts. This study tested two methods of engaging Hispanic and African American women, who were at high risk for cardiovascular disease, in a 10-week aerobic fitness program. The program was offered to 76 participants, in either a women's health clinic or a church. Attendance was the primary dependent variable and was recorded at each exercise session. Other variables, including the Baecke Questionnaire of Habitual Physical Activity, Fat Frequency Questionnaire, Self-Efficacy for Exercise Behaviors Scale, Social Support and Exercise Survey, and Psychological General Well-Being Schedule, were measured prior to the intervention, at the end of the 10-week program, and at 3-month follow-up. Age predicted attendance, independently of site. Women in the highest age quartile (50 - 70 years) attended more than twice as many exercise sessions compared to women in the lowest age quartile (17 - 27 years). The relationship between older age and attendance was particularly strong for Hispanic women. Church parishioners were primarily women over the age of 40, making it impossible to disentangle the relative effect of locale. These findings are relevant for clinicians who design exercise programs targeting older, ethnic, minority women. Administrators who design exercise programs for urban-living women should consider age of the target population when selecting the most conducive setting.

Adolescent↗
PubMed2006

Marathoner's heart?

Explore the source record for details and available documents.

Athletic Injuries↗
PubMed2006

Corneal arcus as coronary artery disease risk factor.

Corneal arcus is a lipid-rich and predominantly extracellular deposit that forms at the corneoscleral limbus. It represents the most common peripheral corneal opacity and is not associated with tissue breakdown but rather with the deposition of lipids. The deposition of cholesterol in the peripheral cornea and arterial wall are similar in that both are accelerated by elevated serum levels of atherogenic lipoproteins, such as low-density lipoproteins (LDL). Corneal arcus is more prevalent in men than in women and in Blacks than in Whites. Its prevalence increases with advancing age. It has been associated with hypercholesterolemia, xanthelasmas, alcohol, blood pressure, cigarette smoking, diabetes, age, and coronary heart disease. Nevertheless, it is not clear whether or not corneal arcus is an independent risk factor for coronary heart disease (CHD). The present systematic review examines the relationship of corneal arcus and CHD to determine if corneal arcus is an independent CHD risk factor. We conclude that there is no consensus that corneal arcus is an independent risk factor. The presence of corneal arcus in a young person should prompt a search for lipid abnormalities. Also, because corneal arcus represents physical evidence of early lipid deposition, its presence suggests the need for aggressive lipid therapy.

Adolescent↗
PubMed2006

Peak systolic blood pressure on a graded maximal exercise test and the blood pressure response to an acute bout of submaximal exercise.

Blood pressure (BP) is immediately reduced after aerobic exercise (postexercise hypotension [PEH]). Whether peak systolic BP on a maximal graded exercise stress test (GEST) relates to PEH is not known. This study examined associations between peak systolic BP on a GEST and PEH. Subjects were 50 men (mean +/- SEM age 43.8 +/- 1.3 years) with elevated BP (145.3 +/- 1.5/85.9 +/-1.1 mm Hg). Men completed a GEST and 3 experiments: nonexercise control and 2 cycle bouts at 40% (LIGHT) and 60% (MODERATE) of maximal oxygen consumption. After the experiments, subjects left the laboratory wearing ambulatory BP monitors. Peak systolic BP on a GEST was categorized into tertiles: low (n = 17, 197.4 +/- 2.0 mm Hg), medium (n = 16, 218.4 +/- 1.4 mm Hg), and high (n = 17, 248.9 +/- 2.8 mm Hg). Repeated-measures analysis of variance tested if BP differed over time and among experimental conditions and peak systolic BP groups. In men with high peak systolic BP, systolic BP was reduced by 7.3 +/- 2.6 mm Hg after LIGHT and by 5.0 +/- 2.2 mm Hg after MODERATE compared with nonexercise control over 10 hours, with the more apparent effects seen after LIGHT (p <0.05). In men with low peak systolic BP, systolic BP was reduced by 6.3 +/- 2.3 mm Hg after MODERATE compared with nonexercise control over 10 hours (p <0.05). In men with medium peak systolic BP, systolic BP was not different after exercise compared with nonexercise control over 10 hours (p >or=0.05). Men with high peak systolic BP had decreased systolic BP to the greatest extent after LIGHT, whereas men with low peak systolic BP reduced systolic BP after MODERATE. In conclusion, the findings of this study suggest that peak systolic BP on a GEST may be used to characterize which men with hypertension will have decreased systolic BP after acute submaximal aerobic exercise.

Adolescent↗
PubMed2006

Rhabdomyolysis associated with pomegranate juice consumption.

This 48-year-old man with possible underlying myopathy was successfully treated with ezetimibe 10 mg/day and rosuvastatin 5 mg every other day for 17 months. Three weeks before presentation, he began drinking pomegranate juice (200 ml twice weekly). He presented urgently with thigh pain and an elevated serum creatine kinase level (138,030 U/L, normal < 200 U/L). In conclusion, because both grapefruit and pomegranate juice are known to inhibit intestinal cytochrome P450 3A4, this report suggests that pomegranate juice may increase the risk of rhabdomyolysis during rosuvastatin treatment, despite the fact that rosuvastatin is not known to be metabolized by hepatic P450 3A4.

Beverages↗
PubMed2006

The effect of apolipoprotein E genotype on serum lipoprotein particle response to exercise.

Exercise affects lipoprotein metabolism and apolipoprotein E (Apo E) genotype may alter changes in lipoprotein subclasses that occur with exercise. The present study examined the effects of Apo E genotype (APOE) on the response of lipoprotein subclass concentrations to long-term exercise. A prospective longitudinal study, conducted at seven centers, genetically screened 566 individuals to create three cohorts of healthy adults, equal for gender and the most common APOE variants: E2/3 (n = 35), E3/3 (n = 40), and E3/4 (n = 31). Subjects with body mass index (BMI) > or = 31 or evidence of dyslipidemia or metabolic disease were excluded. All subjects exercised aerobically at 75% of maximal heart rate for 40 min, four times weekly for 6 months. Fasting lipoprotein subpopulations were measured before and after exercise training using proton nuclear magnetic resonance spectroscopy. Serum lipids for the entire cohort did not change with exercise training, but the LDL subpopulation response varied by APOE. Small-sized LDL particles decreased only in the APOE3 homozygotes whereas medium-sized LDL particles increased only in this group. These changes were directionally different from the responses in the E2/3 and E3/4 subjects (p < 0.05). Neither exercise nor APOE variant affected overall LDL or HDL size or cholesterol concentration, but exercise decreased VLDL diameter by 3.5 nm (p < 0.001) attributable to decreases in large VLDL in each APOE group. In conclusion, APOE variants influence the serum LDL subpopulation response to exercise training in normolipidemic subjects. Subjects homozygous for APOE3 experienced the most beneficial lipid effects from exercise training.

Adolescent↗
PubMed2006

Analysis of human skeletal muscle after 48 h immobilization reveals alterations in mRNA and protein for extracellular matrix components.

We examined the effects of 48 h of knee immobilization on alterations in mRNA and protein in human skeletal muscle. We hypothesized that 48 h of immobilization would increase gene expression and respective protein products for ubiquitin-proteasome pathway (UPP) components. Also, we used microarray analysis to identify novel pathways. Biopsies were taken from the vastus muscle of five men (20.4 +/- 0.5 yr) before and after 48-h immobilization. Global changes in gene expression were analyzed by use of Affymetrix GeneChips. Candidate genes were confirmed via quantitative RT-PCR. Western blotting (WB) was used to quantify protein products of candidate genes and to assess Akt pathway activation. Immunohistochemistry was used to localize proteins found to be altered when assessed via WB. The greatest percentage of genes showing altered expression with the GeneChip included genes involved in the UPP, metallothionein function, and extracellular matrix (ECM) integrity. Quantitative RT-PCR analysis confirmed increases in mRNA for UPP components [USP-6, small ubiquitin-related modifier (SUMO-1)] and the metallothioneins (MT2A, MT1F, MT1H, MT1X) and decreases in mRNA content for matrix metalloproteinases (MMP-28, TIMP-1) and ECM structural components [collagen III (COLIII) and IV (COLIV)]. Only phosphorylated Akt (Ser473, Thr308), COLIII and COLIV protein levels were significantly different postimmobilization (25, 10, 88, and 28% decrease, respectively). Immunohistochemistry confirmed WB showing decreased staining for collagens postimmobilization. Our results suggest that 48 h of immobilization increases mRNA content for components of the UPP and metallothionein function while decreasing mRNA and protein for ECM components as well as decreased phosphorylation of Akt.

Adult↗
PubMed2006

A systematic review of LDL apheresis in the treatment of cardiovascular disease.

LDL apheresis is an effective method of lowering low-density lipoprotein (LDL) concentration in patients with familial hypercholesterolemia (FH) who are either refractory to treatment or intolerant of medical therapy. We searched the medical literature through July 2004 using PubMed and Medline and the search terms "LDL apheresis", "cardiovascular", and "disease" to identify apheresis techniques and to evaluate their effects on cardiovascular pathophysiology and clinical outcomes. We conclude that LDL apheresis reduces cardiovascular events in hypercholesterolemic patients and may be an effective treatment for other vascular diseases including cholesterol embolic disease, focal segmental glomerular sclerosis, sudden hearing loss, and age-related macular degeneration.

Blood Component Removal↗
PubMed2006

RAAS polymorphisms alter the acute blood pressure response to aerobic exercise among men with hypertension.

Limited evidence suggests renin-angiotensin-aldosterone system (RAAS) polymorphisms alter the blood pressure (BP) response to aerobic exercise training. We examined if RAAS polymorphisms influenced postexercise hypotension in men with high normal to Stage 1 hypertension. Forty-seven men (44.2+/-1.4 years, 145.1+/-1.6/85.5+/-1.1 mmHg) randomly completed three experiments: seated rest (control) and two cycle exercise bouts at 40% (LITE) and 60% (MOD) of maximal oxygen consumption. Ambulating BP was measured for 14 h after each experiment. RAAS polymorphisms associated with hypertension (i.e. angiotensin converting I enzyme, ACE I/D; angiotensin II type 1 receptor, AT1R A/C; and intron 2 of aldosterone synthase, Int2 W/C) were analyzed using polymerase chain reaction and restriction enzyme digestion. Repeated measure ANOVA tested if BP differed between experimental conditions by RAAS genotypes. Compared to men with 0-2 variant alleles, men with > or =3 combined RAAS variant alleles had lower average systolic BP (SBP) (P=0.030) and lower average diastolic BP (DBP) (P=0.009) for 14 h only after LITE. In contrast, average BP was not different for MOD and control between RAAS variant allele groups over this time period (P> or =0.05). LITE reduced BP in men with > or =3 variant RAAS alleles for 14 h, whereas MOD had no influence on BP in these men. In order to optimally prescribe exercise for its BP lowering benefits in those with hypertension, additional knowledge of how genetic variation affects the BP response to exercise is needed.

Adult↗
PubMed2006

An assessment of statin safety by muscle experts.

The National Lipid Association's (NLA) Muscle Safety Expert Panel was charged with the duty of examining the definitions, causative factors, and management of statin myopathy. The Panel was asked to use its evidence-based findings to form recommendations in response to a series of specific questions posed by the Task Force. The panel was composed of a clinical cardiologist, an exercise physiologist and skeletal muscle expert, and an expert in preventive cardiology who also examined skeletal muscle complications of statin use.

Biopsy↗
PubMed2006

Randomized trial of hormone therapy in women after coronary bypass surgery. Evidence of differential effect of hormone therapy on angiographic progression of disease in saphenous vein grafts and native coronary arteries.

Clinical trials indicate that hormone therapy (HT) does not decrease cardiovascular disease events or angiographic coronary disease progression. The effects of HT on SVG vessels are unknown. To determine whether postmenopausal hormone therapy started after coronary bypass surgery (CABG) decreases saphenous vein graft (SVG) disease, we conducted a multicenter randomized placebo-controlled angiographic study of estradiol+/-medroxyprogesterone started within 6 months of CABG in 83 postmenopausal women. Angiographic and intravascular ultrasound (IVUS) assessment at 6 and 42 months was planned to assess SVG disease progression. The study was stopped early following publication of the Women's Health Initiative Estrogen/Progestin study. Eighty-three subjects underwent a 6-month angiogram with 63 undergoing IVUS. Forty-five subjects completed the 42-month angiogram (20 underwent 42-month IVUS). In analysis of paired 6- and 42-month angiogram and IVUS studies, HT slowed angiographic progression of SVG disease assessed by mean percent stenosis (p<0.001), minimal lumen diameter (p=0.029), and total plaque volume (p=0.006). In contrast, HT accelerated disease progression in non-bypassed native coronary arteries (minimum lumen diameter, p=0.01). SVG disease and closure occurred in 38% subjects within 1-year post-CABG. The groups had similar frequency of cardiovascular events expect for angioplasty that occurred in eight HT compared to one placebo subject (p<0.05). In HT subjects angioplasty was indicated for native coronary arterial stenoses while in the placebo subject angioplasty was indicated for SVG stenosis. This study suggests that hormone treatment may slow SVG disease progression while accelerating atherosclerosis in non-bypassed native coronary arteries.

Coronary Angiography↗
PubMed2006

The influence of short and long duration on the blood pressure response to an acute bout of dynamic exercise.

BACKGROUND: The minimum duration of exercise needed to acutely lower blood pressure (BP) has not been established. The purpose of this study is to compare the effects of short and long duration on the BP response to a session of aerobic exercise. METHODS: Subjects were 45 men (mean +/- SEM, 43.4 +/- 1.5 years) with elevated BP (144.6 +/- 1.6/85.2 +/- 1.1 mm Hg). Using a parallel design, men were randomly assigned to 40% (LITE, n = 23) or 60% (MOD, n = 22) of maximal oxygen consumption. Following assignment, they completed 3 experiments: a no-exercise control, and a 15-minute SHORT and 30-minute LONG cycle bout. Subjects left the laboratory wearing an ambulatory BP monitor. Repeated measure analysis of variance tested if BP differed among experimental conditions (no-exercise control, LONG, and SHORT) and over time within groups (LITE and MOD). RESULTS: For 9 hours, systolic BP increased from baseline after all conditions (P < .001); however, systolic BP was reduced by 5.6 +/- 2.0 and 4.3 +/- 1.6 mm Hg after SHORT and LONG with LITE, and 4.1 +/- 1.6 and 4.9 +/- 1.9 mm Hg with MOD, respectively, compared with no-exercise control (P < .05). For 9 hours, diastolic BP (DBP) decreased from baseline after all conditions (P < .001). DBP was reduced by 2.1 +/- 1.0 and 3.6 +/- 1.4 mm Hg after SHORT and LONG with MOD for 3 hours (P < .05), and average DBP was lower by 2.4 +/- 1.0 mm Hg after LONG with LITE for 9 hours versus no-exercise control (P < .05). CONCLUSIONS: The immediate BP-lowering effects of short-duration, lower intensity exercise are comparable to those of higher amounts of exercise. Additional investigation is needed to better quantify the dose of exercise needed to lower BP.

Adolescent↗