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Biomedical subjects

L B Synovitz

Publications and source records attributed to L B Synovitz.

6 recordsLinked to original sources
PubMed2002

Glucoregulatory endocrine responses to intermittent exercise of different intensities: plasma changes in a pancreatic beta-cell peptide, amylin.

Amylin, a peptide hormone released from the beta cells of the pancreas and cosecreted with insulin, is reported to inhibit the release of postprandial glucagon and insulin and to modulate gastric emptying. Changes in insulin and glucagon are important for controlling blood glucose levels under conditions in which metabolic rate is elevated, such as during and following exercise. Amylin may participate in the regulation of blood glucose levels in response to exercise, although the role of amylin has not been investigated. The purpose of the study was to determine the effects of a progressive, intermittent exercise protocol on amylin concentrations and to compare its response to circulating levels of insulin, glucagon, cortisol, and glucose. Seven well-trained males completed an intermittent exercise trial on a treadmill at four progressive exercise intensities: 60%, 75%, 90%, and 100% of maximum oxygen consumption (.VO(2)max). Blood samples were collected before exercise, after each exercise intensity, and for 1 hour following the exercise protocol. Subjects also completed a control trial with no exercise. Amylin and insulin rose from baseline (5.79 +/-.78 pmol/L and 4.76 +/-.88 microIU/mL) to peak after 100% .VO(2)max (9.16 +/- 1.35 pmol/L and 14.37 +/- microIU/ml), respectively and remained elevated during much of recovery. Thus, a progressive intermittent exercise protocol of moderate to maximum exercise intensities stimulates increases in amylin levels in well-trained individuals in a similar fashion to that of insulin, whereas glucagon concentrations only increase after the greatest exercise intensity, then quickly decline. Future studies should examine the effects of higher amylin concentrations in exercise recovery on glucoregulation.

Adult↗
PubMed2001

Leptin and steroid hormone responses to exercise in adolescent female runners over a 7-week season.

The purpose of the study was to investigate the responses of leptin and steroid hormones to maximal exercise in adolescent female runners over a competitive season. Seven adolescent female distance runners completed three testing trials during weeks 1.4 and 7 of their high-school track season. Blood samples were collected before and after a discontinuous graded exercise test to exhaustion (GXT) for each trial. Tests were administered during the subjects' normal training time (3:30 p.m.-5:00 p.m.). Compared to week 1, peak O2 uptake rose significantly during the season and was 10% and 7% higher at weeks 4 and 7, respectively. Levels of dehydroepiandrosterone (DHEA), dehydroepiandrosterone sulfate (DHEAS), cortisol, testosterone, and leptin increased significantly in response to the graded exercise tests. Testosterone levels were also changed over the course of the study. Resting testosterone levels and testosterone responses to exercise in weeks 4 and 7 were both higher than in week 1. Resting concentrations and acute increases of the other hormones were not changed over the season. It appears, therefore, that DHEA, DHEAS, cortisol, testosterone and leptin concentrations increase in response to running in adolescent female runners. Data also suggest that training and/or maturation increases resting testosterone concentrations and testosterone responses to running in adolescent female runners during a training season.

Adolescent↗
PubMed2001

Effect of estrogen on serum DHEA in younger and older women and the relationship of DHEA to adiposity and gender.

This case-controlled study consisted of 2 parts. The objective of part 1 was to determine the relationship between DHEA, body mass index (BMI), and age in young males, young females, and postmenopausal (PM) females. Part 2 examined the effects of estrogen on DHEA by analyzing the relationship between DHEA and age in young females on and off oral contraceptives (OCs) and PM females on and off estrogen or hormone replacement therapy (ERT/HRT). The study was performed at the Obstetrics and Gynecology Clinic, Texas Tech Health Sciences Center-Amarillo, Exercise Physiology Laboratory at Southeastern Louisiana University, and Woman's Health Research Institute, Woman's Hospital, Baton Rouge, LA. Part 1 groups consisted of: (1) young males between the ages of 18 to 40 years; (2) normally cycling females off OCs, ages 18 to 40 years; and (3) PM females older than 40 years not receiving ERT/HRT. Part 2 groups consisted of: (1) normally cycling females on OCs, ages 18 to 40 years;, (2) normally cycling females off OCs, ages 18 to 40 years; (3) PM females 50 years or older not receiving ERT/HRT; and (4) PM females 50 years or older receiving ERT/HRT. The main outcome measure was serum DHEA concentrations. For part 1, there were significant (P <.05) inverse relationships between DHEA and age for young males; young females, off OCs; PM females, no ERT/HRT r = -.44, -.26, and -.25, respectively. There were no significant relationships between DHEA and BMI for any of the groups. DHEA concentrations were significantly higher in young males than young females even after accounting for age. For part 2, DHEA concentrations were significantly higher in young females off OCs compared with young females on OCs, and significantly higher in PM women off ERT/HRT than those on ERT\HRT. There were significant inverse relationships between DHEA and age for young females and PM females on and off ERT/HRT. From these findings, we conclude that there is an inverse relationship between DHEA and age for young males, young females off OCs, and PM females, no ERT/HRT. No relationship between BMI and DHEA was observed in these same 3 groups. These results agree with previous findings in young men, but differ from previous findings in obese young females. The data also suggest that estrogen treatment (OCs and ERT/HRT) suppresses DHEA concentrations in premenopausal and PM females, and that DHEA declines with age in PM females regardless of estrogen treatment.

Adipose Tissue↗
PubMed1999

Using puppetry in a coordinated school health program.

Educators and clinicians are continually searching for innovative methodologies that promote positive health behaviors, that are age and developmentally appropriate, and that are fun. Puppetry meets these criteria. Puppetry is a creative learning methodology that stimulates learning through play. Various types of puppets are identified and a summary of the ways in which puppets may be used in a coordinated school health program to enhance positive health behaviors is presented. While many individuals attest to the value of using puppets, research should be conducted to assess effectiveness of puppetry on health knowledge, attitudes, skills, and behaviors.

Adolescent↗
PubMed1998

Antecedents of sexual victimization: factors discriminating victims from nonvictims.

A sexual victimization survey was used to assess the factors that would discriminate between victims and nonvictims of sexual assault. The sample consisted of 241 female college students at a large midwestern university. Victimization status was ascertained from the 13-question Sexual Experiences Survey developed by Koss and Gidycz and Koss and Oros. Data eliciting information about possible associated factors (demographics, dating history, sexual history, personality characteristics and traits) and victimization status were obtained by adapting several scales and instruments into a single Dating and Relationship Survey. Of the 241 women, 102 reported they had been victimized. Discriminant function analysis was used to develop a set of variables that significantly identified victimization status. The variables found to be related to women's being sexually victimized were (a) number of different lifetime sexual partners, (b) provocative dress, and (c) alcohol use.

Adolescent↗