School of Public Health

Permanent URI for this communityhttp://hdl.handle.net/1903/1633

The collections in this community comprise faculty research works, as well as graduate theses and dissertations.

Note: Prior to July 1, 2007, the School of Public Health was named the College of Health & Human Performance.

Browse

Subject: search.filters.subject.Biology, Animal Physiology

Search Results

Now showing 1 - 4 of 4
  • Thumbnail Image
    Item
    NFKB1 Gene Promoter Polymorphism and Unidirectional Laminar Shear Stress: Implications for NF-kB Activation, eNOS Protein Expression and Endothelial Function
    (2006-06-04) Park, Joon Young; Brown, Michael D.; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Exercise stimulus can be defined as endothelial wall shear stress. In the endothelial cells, the nuclear factor-kappa B (NF-κB) is an important intracellular signaling molecule by which changes in wall shear stress, sensed by mechanosensors, are transduced into the nucleus to initiate downstream eNOS gene expression. Recently, a polymorphism in the promoter region of the gene encoding a p50/p105 NF-κB subunit, NFKB1, has been identified. The NFKB1 ATTG insertion (I) / deletion (D) (NFKB1 I/D) promoter polymorphism transcriptionally regulates NFKB1 gene expression. However, the functional significance of this polymorphism has not been elucidated in endothelial cells under LSS and in endothelial function in humans. Therefore, the purpose of this study was to investigate whether the NFKB1 I/D promoter polymorphism had functional genetic properties in human umbilical vein endothelial cells (HUVECs) under physiological levels of unidirectional laminar shear stress (LSS), and further, whether the polymorphism was associated with changes in endothelial function after endurance exercise training in pre- and stage I hypertensive individuals. The major findings of the present study were that 1) a protein present in HUVECs preferentially and specifically binds to the I allele promoter compare to the D allele; 2) the I allele had significantly higher promoter activity than the D allele; and accordingly, the II homozygote cells had higher p50/p105 NFKB1 protein levels than the DD homozygote cells; 3) the II homozygote cells showed a greater increase in eNOS protein levels than the DD homozygote cells under unidirectional LSS; and 4) the I-allele carrier group had a greater reactive hyperemic forearm blood flow response, a measure of endothelial function, before exercise training; however, the NFKB1 I/D polymorphism was not significantly associated with the differential changes in endothelial function following exercise training. These results have potential clinical implications for endothelial dysfunction that are related to the development and progression of atherosclerosis and cardiovascular disease. In addition, our findings provide insight into the molecular mechanisms involved in the intracellular signaling transduction process of eNOS gene expression and function of the NFKB1 gene promoter region.
  • Thumbnail Image
    Item
    EFFECTS OF ACUTE POSTURAL CHANGE ON MID-THIGH CROSS-SECTIONAL AREA AS MEASURED BY COMPUTED TOMOGRAPHY
    (2005-12-07) cerniglia, linda michelle; Rogers, Marc; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Fluid shifts resulting from postural change present a potential source of error when assessing the CSA of limb tissue using CT. In the present study mid-thigh axial scans of 13 older women were obtained at 5, 10, and 15 minutes of supine rest. Scans were analyzed for changes in CSA of subcutaneous fat(SF), low density muscle(LDM) and normal density muscle(NDM) tissue. A significant decrease was found in NDM CSA at 15 minutes (2.3 ± 0.8, 1.6%, P<0.05) with no change in LDM or SF CSA between any time interval The current study suggests that the potential measurement error associated with fluid shifting out of the tissues can be minimized when baseline and follow-up CT-derived images of mid-thigh CSA are obtained within the first 10 minutes the subject assumes the supine position and that the CSA of NDM and LDM may be affected differently by loss of hydrostatic pressure.
  • Thumbnail Image
    Item
    EFFECT OF ENDURANCE EXERCISE TRAINING ON FASTING AND POSTPRANDIAL PLASMA ADIPONECTIN LEVELS
    (2005-07-12) Brandauer, Josef; Hagberg, James M; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    The purpose of this study was to investigate the postprandial response of plasma adiponectin (AN) levels to a high-calorie, high-fat meal, in relatively healthy (free of diabetes, overt heart disease) sedentary 50- to 75-year-old men and women before and after a six-month endurance exercise training program (approximately 70% of VO2 max, three times per week). AN is an adipocyte-released polypeptide ("adipokine") whose physiological significance in insulin sensitivity and other health risk factors is well documented. VO2 max was significantly increased with training in both men and women (men, 27.0 ± 0.9 vs. 32.2 ± 1.2 mL/kg/min, p < 0.0001; women, 23.3 ± 1.0 vs. 27.1 ± 1.4 mL/kg/min, p = 0.0002), while % body fat was decreased (men, 29.9 ± 1.2 vs. 26.0 ± 1.3 %, p = 0.0010 ; women, 42.3 ± 1.5 vs. 39.5 ± 1.8 %, p < 0.0001). Fasting AN levels were higher in women than in men (gender main effect, p = 0.0138), and fasting as well as postprandial adiponectin levels decreased significantly with training in men (p = 0.014) but not in women. No postprandial changes in plasma AN levels were observed in either gender. Stepwise regression analysis showed insulin sensitivity to be the strongest predictor of fasting AN levels. Postprandial AN levels were mainly dependent on fasting AN concentrations. In conclusion, fasting plasma adiponectin levels decreased with exercise training in men in the present study, whereas they remained unchanged in women. Postprandial adiponectin levels did not change following consumption of a high-fat meal either before or after exercise training.
  • Thumbnail Image
    Item
    Insulin-like Growth Factor 1 Genotype Influences Muscle Strength Response to Sterngth Training in Older Adults
    (2004-11-03) kostek, matt; Hurley, Ben F; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Strength training (ST) is considered an intervention of choice for the prevention and treatment of sarcopenia. The insulin-like growth factor 1 protein (IGF-I) plays a major role in ST-induced skeletal muscle hypertrophy and strength improvements. A microsatellite repeat in the promoter region of the IGF1 gene has been associated with IGF-I blood levels and phenotypes related to IGF-I in adult men and women. To examine the influence of this polymorphism on muscle hypertrophic and strength responses to strength training (ST), we studied 67 Caucasian men and women before and after a 10-week single leg knee extension ST program. One repetition maximum (1RM) strength, muscle volume (MV) via computed tomography (CT), and muscle quality (MQ) were assessed at baseline and after 10 weeks of training. The IGF1 repeat promoter polymorphism and three single nucleotide polymorphisms (SNP) were genotyped. For the promoter polymorphism, subjects were grouped as homozygous for the 192 allele, heterozygous, or non-carriers of the 192 allele. After 10 weeks of training, 1RM, MV, and MQ increased significantly for all groups combined (P < 0.001). However, carriers of the 192 allele gained significantly more strength with ST than non-carriers of the 192 allele (P = 0.02). There was also a non-significant trend for a greater increase in MV in 192 carriers than non-carriers (P = 0.08). No significant associations were observed for the other polymorphisms studied. Thus, these data suggest that the IGF1 promoter polymorphism may influence the strength response to ST. Larger sample sizes should be used in future studies to verify these results