Glycopeptide N-acetylgalactosaminyltransferase specificities for O-glycosylated sites on MUC5AC mucin motif peptides

The recombinant proteins of the two novel UDP-N-acetylgalactosamine (GalNAc) glycopeptide:N-acetylgalactosaminyltransferases (designated gpGaNTase-T7 and gpGaNTase-T9) were assayed with O-glycosylated products obtained from the prior action of the ubiquitous transferases (GaNTase-T1 and GaNTase-T2) towards MUC5AC mucin motif peptides (GTTPSPVPTTSTTSAP and peptides with single amino acid substitutions, GTTPSAVPTTSTTSVP and GTTPSPVPTTSITSVP, that are a reflection of mucin molecule polymorphism). gpGaNTase-T9 is known to be expressed differentially and more abundantly than gpGaNTase-T7 in some tissues; the results of in vitro glycosylation also indicates a difference in acceptor substrate specificities between the gpGaNTase isoforms. With the use of capillary electrophoresis, MS and Edman degradation, our study suggests that, in the O-glycosylation of mucin-type proteins, approach and recognition signalling by gpGaNTase-T7 and gpGaNTase-T9 depend largely on the peptide's primary structure (for example the presence of multiple clusters of hydroxy amino acids and the number of GalNAc residues attached to the peptide backbone). O-glycosylation in terms of sites of attachment seems to be less random than previously described and, if sequential reactions are ordered throughout the Golgi stack, the complete O-glycosylation of the mucin molecules seems to be finely tuned to respond to specific damage to, or attack on, epithelia.

Age, body mass index, race and other determinants of steroid hormone variability: the HERITAGE Family Study

OBJECTIVE AND METHODS

To investigate from the HERITAGE Family Study database, 13 steroid hormones (androstane-3alpha, 17beta-diol glucuronide, androsterone glucuronide, cortisol, dehydroepiandrosterone (DHEA), DHEA ester (DHEAE), DHEA sulfate (DHEAS), dihydrotestosterone (DHT), estradiol, 17-hydroxyprogesterone, progesterone, pregnenolone ester, sex hormone binding globulin (SHBG) and testosterone in each sex for their relationships with age, body mass index (BMI), race and key lifestyle variables. Sample sizes varied from 676 to 750 per hormone. Incremental regression methods were used to examine the contributions of the variables to steroid hormone variability.

RESULTS

Age was a major predictor for most steroid hormones. The greatest contribution of age was a negative relationship with DHEAS (R(2)=0.39). BMI was also associated with the variability of several steroid hormones, being the most important predictor of SHBG (R(2)=0.20) and of testosterone (R(2)=0.12) concentrations. When age and BMI were included, race still contributed significantly to the variations in cortisol (R(2)=0.02 for men and 0.04 for women), DHT (R(2)=0.02 for men and 0.03 for women), and progesterone (R(2)=0.03 for women). Nevertheless, race appeared to be less important than age and BMI. In addition, lifestyle indicators (food and nutrient intakes, smoking and physical activity) influenced steroid hormone variability. Their contributions, however, were minor in most cases once age, BMI and race had been taken into account.

CONCLUSIONS

We conclude that age was the most important factor, followed by BMI, race and lifestyle factors in explaining steroid hormone variability.

Genomic scan for exercise blood pressure in the Health, Risk Factors, Exercise Training and Genetics (HERITAGE) Family Study

Agenome-wide linkage scan was performed for genes affecting submaximal exercise systolic blood pressure (SBP) and diastolic blood pressure (DBP) in the sedentary state and their responses to a standardized endurance training program. A total of 344 polymorphic markers were used, and 344 pairs of siblings from 99 white nuclear families and 102 sibling pairs from 105 black family units were available for the study. All subjects were healthy but sedentary at baseline. SBP and DBP were measured during exercise tests at 2 different intensities: 50 W (SBP50 and DBP50) and 80% of maximal oxygen consumption (SBP80 and DBP80). Baseline blood pressure phenotypes were adjusted for age, gender, and body mass index, and the training responses (after training minus baseline [Delta]) were adjusted for age, gender, baseline body mass index, and baseline blood pressure. Two analytical strategies were used: a multipoint variance-components linkage analysis using all the family data and a single-point linkage analysis using pairs of siblings. In whites, promising linkages (lod score >1.75) were detected for baseline SBP80 on 10q23-q24 and for DeltaSBP50 on 8q21. In addition, several chromosomal regions with suggestive evidence of linkage (lod score 1.0 to 1.75) were observed for SBP50 (22q11.2-q13), DBP50 (6q23-q27), SBP80 (2p24, 2q21, 14q11.1-q12, and 16q21), DBP80 (6q13-q21), DeltaSBP50 (7p12-p13), and DeltaDBP50 (5q31-q32). In blacks, DBP50, DBP80, and DeltaDBP80 showed promising quantitative trait loci on 18p11.2, 11q13-q21, and 10q21-q23, respectively. Suggestive linkages were evident for DBP50 on 2p22-p25, 11p15.5, and 18q21.1; for SBP80 on 6q21-q21, 6q31-q36, 12q12-q13, 15q12-q13, and 17q11-q12; and for DBP80 on 8q24, 10q21-q24, and 12p13. All the detected chromosomal regions include several potential candidate genes and therefore warrant further studies in the Health, Risk Factors, Exercise Training and Genetics (HERITAGE) cohort and other studies.

Changes in blood lipids consequent to aerobic exercise training related to changes in body fatness and aerobic fitness

The contribution of changes in body fatness and aerobic fitness to changes in blood lipids after aerobic exercise training was investigated. The sample included 295 men (77 black, 218 white) and 355 women (131 black, 224 white), aged 17 to 65 years, from the HERITAGE Family Study. Participants underwent measurements at baseline and after 20 weeks of supervised exercise training on a cycle ergometer. Body fat mass (FM, in kilograms) was determined by underwater weighing, and aerobic fitness (maximal oxygen uptake, VO(2max), in milliliters per minute) was assessed by cycle ergometry. Blood lipid measurements included fasting plasma levels of high-density lipoprotein cholesterol (HDL-C), HDL(2)-C, HDL(3)-C, low-density lipoprotein cholesterol (LDL-C), total cholesterol (CHOL), CHOL/HDL, and triglycerides (TG). A composite lipid change index (LCI) was derived by subjecting the Delta scores for the individual blood lipids to principal components analysis. The exercise training was accompanied by a mean increase of 17.5% in VO(2max) and a mean decrease of 3.3% in FM. Partial correlations, controlled for age, between absolute changes in VO(2max) and changes in the blood lipids were consistently low and nonsignificant. On the other hand, absolute changes in FM were significantly (P <.05) associated with changes in HDL-C (r = -.23), HDL(2)-C (r = -.17), and CHOL/HDL (r =.24) and the LCI (r = -.27) in men and with changes in LDL-C (r =.22), CHOL (r =.19), and CHOL/HDL (r =.15) and the LCI (r = -.19) in women. Forward stepwise regression confirmed that the change in FM was a better predictor of changes in blood lipids than the change in VO(2max), entering as a predictor in 4 of 8 regressions in both men and women. Change in VO(2max) did not enter as a significant predictor in any regression. Further, there were no differences in LCI between the upper and lower quartiles of VO(2max) change. On the other hand, there were significant differences between the low and high quartiles of FM change. No race effects were observed in any of the relationships, except that race was a significant predictor of changes in TG in both men and women. In conclusion, changes in blood lipids associated with aerobic exercise training do not appear to be related to changes in aerobic fitness per se; rather, they are weakly to moderately associated with changes in body fatness.

The Trp64Arg polymorphism of the beta3-adrenergic receptor gene is not associated with training-induced changes in body composition: The HERITAGE Family Study

OBJECTIVE

To investigate the association between the Trp64Arg polymorphism of the beta3-adrenergic receptor gene and changes in body composition in response to endurance training.

RESEARCH METHODS AND PROCEDURES

Adult sedentary white and black subjects participating in the HERITAGE Family Study were measured before and after 20 weeks on endurance training for the body mass index, fat mass, percentage of body fat, fat-free mass, sum of eight skinfolds, and subcutaneous, visceral, and total abdominal fat areas. The association between the Trp64Arg polymorphism and the response phenotypes, computed as the difference between pre- and post-training values, was tested by analysis of covariance separately in men and women. The gene by race interaction term was also tested.

RESULTS

No race differences were observed for allelic and genotype frequencies. Training resulted in significant reduction of body fat in both men and women. No association of the Trp64Arg polymorphism was observed with training-induced changes for any of the body composition phenotypes in both men and women.

DISCUSSION

These results suggest that the Trp64Arg polymorphism of the beta3-adrenergic receptor gene is not related to changes in body composition in response to exercise training.

Age, sex, race, initial fitness, and response to training: the HERITAGE Family Study

Effects of age, sex, race, and initial fitness on training responses of maximal O(2) uptake (VO(2 max)) are unclear. Data were available on 435 whites and 198 blacks (287 men and 346 women), aged 17-65 yr, before and after standardized cycle ergometer training. Individual responses varied widely, but VO(2 max) increased significantly for all groups. Responses by men and women and by blacks and whites of all ages varied widely. There was no sex difference for change (Delta) in VO(2 max) (ml. kg(-1). min(-1)); women had lower initial values and greater relative (%) increases. Blacks began with lower values but had similar responses. Older subjects had a lower Delta but a similar percent change. Baseline VO(2 max) correlated nonsignificantly with DeltaVO(2 max) but significantly with percent change. There were high, medium, and low responders in all age groups, both sexes, both races, and all levels of initial fitness. Age, sex, race, and initial fitness have little influence on VO(2 max) response to standardized training in a large heterogeneous sample of sedentary black and white men and women.

Genomic scan for genes affecting body composition before and after training in Caucasians from HERITAGE

An autosomal genomewide search for genes related to body composition and its changes after a 20-wk endurance-exercise training program has been completed in the HERITAGE Family Study. Phenotypes included body mass index (BMI), sum of eight skinfold thicknesses, fat mass (FM), fat-free mass, percent body fat (%Fat), and plasma leptin levels. A maximum of 364 sib-pairs from 99 Caucasian families was studied with the use of 344 markers with single-point and multipoint linkage analyses. Evidence of significant linkage was observed for changes in fat-free mass with the S100A and the insulin-like growth factor I genes (P = 0.0001). Suggestive evidence (2.0 < or = Lod < 3.0; 0.0001 < P < or = 0.001) was also observed for the changes in FM and %Fat at 1q31 and 18q21-q23, in %Fat with the uncoupling protein 2 and 3 genes, and in BMI at 5q14-q21. At baseline, suggestive evidence was observed for BMI at 8q23-q24, 10p15, and 14q11; for FM at 14q11; and for plasma leptin levels with the low-density lipoprotein receptor gene. This is the first genomic scan on genes involved in exercise-training-induced changes in body composition that could provide information on the determinants of weight loss.

Fitness, fatness, and estimated coronary heart disease risk: the HERITAGE Family Study

PURPOSE

To determine the contributions of fatness and fitness to the estimated risk of future coronary heart disease (CHD).

METHODS

The sample consisted of 212 black and 411 white adult sedentary participants. Percent body fat (%BF) was measured using densitometry, whereas maximal oxygen uptake (VO(2max)) was measured on a cycle ergometer. Risk of future CHD was estimated using the revised Framingham Heart Study algorithm.

RESULTS

For fatness, the odds ratios for risk of future CHD were 1.83 and 1.70 for the moderate and high tertiles, respectively, compared with the low tertile. Similarly, the odds ratios for VO(2max) were 1.29 (NS) and 1.62, for the moderate and low tertiles, respectively. Removing VO(2max) from the full model had no effect; however, removing %BF resulted in a significantly weaker model (chi(2) = 10.38, P < 0.01).

CONCLUSION

Both fatness and fitness are important predictors of risk of future CHD, based on the Framingham index.

Familial aggregation of submaximal aerobic performance in the HERITAGE Family study

PURPOSE

This study examines the contribution of genetic factors to submaximal aerobic performance phenotypes measured before and after 20 wk of endurance training.

METHODS

Submaximal oxygen consumption (VO(2)) at three power outputs, 50 W (VO(2)50W), 60% (VO(2)60%) and 80% (VO(2)80%) of VO(2max) and power outputs at 60% (PO60%) and 80% (PO80%) of VO(2max) were measured during cycle ergometer exercise tests in 483 subjects from 99 white families participating in the HERITAGE Family study. The baseline phenotypes were adjusted for the effects of age, sex, and body mass using stepwise multiple regression procedures. The response phenotypes, computed as the difference (Delta) between the posttraining and baseline measures, were adjusted for age, sex, and the baseline value.

RESULTS

All submaximal exercise phenotypes measured at baseline and in response to training were characterized by a significant familial resemblance. Maximal heritabilities of the baseline phenotypes range from 48% to 74% with significant spouse, sibling, and parent-offspring correlations. The hypothesis of maternal inheritance where mother-offspring and sibling correlations were forced to be equal was found to fit the data for VO(2)60%, VO(2)80% and PO80%. For the response phenotypes, the maximal heritabilities tended to be lower (23--57%) with a significant maternal inheritance for Delta VO(2)60%, Delta PO60%, and Delta PO80%.

CONCLUSION

These results suggest that the submaximal working capacities of sedentary subjects and their responses to endurance training are influenced by familial/genetic factors with a significant contribution of maternal inheritance.

Angiogenin gene-race interaction for resting and exercise BP phenotypes: the HERITAGE Family Study

We examined the association between an angiogenin gene polymorphism and blood pressure (BP) at rest and in response to acute exercise before and after a 20-wk endurance-training program. Subjects were 737 normotensive and borderline hypertensive subjects (257 black and 480 white). The polymorphism was detected by PCR and digestion with AvaII, yielding an allele of 253 bp or a rare allele of 194 + 59 bp. Resting and exercise [50 W; 60, 80, and 100% of maximal O2 consumption (VO2 max)] systolic (SBP) and diastolic BP were determined before and after training. Among blacks, adjusted SBP in the sedentary state was significantly lower in carriers of the rare allele at rest and exercise intensities of 60, 80, and 100% of VO2 max. In the trained state, carriers of the rare allele had a significantly (P < 0.05) lower SBP than did noncarriers at rest and at 80 and 100% of VO2 max. The genotypic effect observed among blacks was not evident among whites. Furthermore, change in BP (after--before) was not significantly associated with the genotype. In conclusion, the angiogenin gene AvaII polymorphism is associated with a lower SBP at rest and in response to acute high-intensity exercise in blacks but not in whites.

Familial resemblance for coronary heart disease risk: the HERITAGE Family Study

The objective of this study was to quantify familial resemblance for coronary heart disease risk in 260 Black and 427 White participants in the HERITAGE Family Study. Coronary heart disease risk was estimated using a coronary heart disease risk index (CHDRI) computed from the revised Framingham Heart Study algorithm, based on age, LDL-cholesterol, HDL-cholesterol, blood pressure, diabetes, and smoking status. Using a familial correlation model to test hypotheses regarding familial aggregation, significant familial resemblance was detected in both Blacks and Whites. There were significant sibling correlations in both Blacks and Whites, while spouse correlations were significant only in the White sample. The maximal heritabilities, which have to be interpreted cautiously in light of negligible parent-offspring correlations, were 34% and 53% in Whites and Blacks, respectively. Thus, the maximal heritability, which includes both genetic and non-genetic sources of variation, is higher in Blacks than Whites, and explains a significant proportion of the total phenotypic variance. The results indicate that risk of coronary heart disease runs along family lines, and common environmental effects are important in explaining the observed familial resemblance.

Comparison of the PR mutant with the wild-type strain of proteus mirabilis brings insight into peroxide resistance factors and regulation of catalase expression

The peroxide resistant mutant (PR) of Proteus mirabilis was characterized by an increased constitutive catalase activity concomitant with a large production of specific mRNA. Survival toward hydrogen peroxide during exponential phase was increased by H2O2 pretreatment in the wild type but not in the mutant, although the catalase of both strains was not inducible under these conditions. In the mutant, besides catalase, over-produced proteins comprised two different alkyl hydroperoxide reductase subunit C (AhpC) proteins and a protein homologous to the stationary phase transcription factor SspA of Escherichia coli. Conversely, the flagellin A (FlaA) of P. mirabilis was repressed in the PR mutant. Genomic DNA fragments of 2.9 kb carrying the catalase gene (katA) together with the 5' and 3' flanking regions were isolated from both strains and found to be identical. Upstream of katA, a Fur box-like sequence was found, but surprisingly, restricting iron in the culture medium caused a decrease in catalase production. The PR mutant presents similarities with other peroxide resistant mutants, but the regulation of catalase biosynthesis in P. mirabilis seems somewhat different from other close species such as E. coli.

Heart rate and blood pressure changes with endurance training: the HERITAGE Family Study

PURPOSE

The purpose of this study was to determine the magnitude of change in resting and exercise heart rate (HR) and blood pressure (BP), by race, sex, and age, after a 20-wk endurance training program in 507 healthy and previously sedentary subjects from the HERITAGE Family Study.

METHODS

After baseline measurements, subjects exercised on cycle ergometers 3 d x wk(-1) for a total of 60 exercise sessions starting at 55% of VO2max for 30 min x session(-1) and building to 75% of VO2max for 50 min x session(-1) for the last 6 wk. HR and BP at rest and during exercise (50 W, 60% of VO2max maximal exercise) were each determined in duplicate on two different days both before and after training (resting values at 24-h and 72-h posttraining).

RESULTS

After the period of training, there was a small decrease in resting HR (-2.7 to -4.6 beats x min(-1) across groups at 72-h posttraining), and small changes (i.e., < 3 mm Hg) in resting systolic (SBP), diastolic (DBP), and calculated mean BP (MBP), which varied by race, sex, and age. During exercise at the same absolute work rate (50 W), HR, SBP, DBP, and MBP were all significantly reduced, with greater reductions in HR in women compared with men, and greater reductions in BP in blacks and older subjects compared with whites and younger subjects, respectively. At the same relative work rate (60% VO2max), HR, DBP, and MBP were reduced, but SBP remained unchanged. Blacks had a greater reduction in DBP, but whites had a greater reduction in HR. Finally, at maximal exercise, there was a small decrease in HR, with men and whites decreasing more than women and blacks; an 8 mm Hg increase in SBP, with men increasing more than women; a 4 mm Hg decrease in DBP, with blacks decreasing more than whites; and no change in MBP.

CONCLUSION

In conclusion, the reductions in resting HR and BP with training were generally small, but the reductions during exercise were substantial and clinically important, with the older and the black populations experiencing greater reductions.

Cardiac output and stroke volume changes with endurance training: the HERITAGE Family Study

PURPOSE

The purpose of this study was to determine the magnitude of changes in cardiac output (Qc), stroke volume (SV), and arterial-mixed venous oxygen difference (a-vO2 diff) during submaximal exercise following a 20-wk endurance training program, with the primary focus on identifying differences in response by race, sex, and age.

METHODS

The participants in this study (N = 631) were healthy and previously sedentary men (N = 277) and women (N = 354) of varying age (17-65 yr) and race (blacks, N = 217; whites, N = 414) who had completed the HERITAGE Family Study protocol. After baseline measurements, participants trained on cycle ergometers 3 d x wk(-1) for a total of 60 exercise sessions starting at the HR associated with 55% of maximal oxygen uptake (VO2max) for 30 min/session and building to the HR associated with 75% of VO2max for 50 min/session, which was maintained during the last 6 wk. HR, Qc (CO2 rebreathing), and SV (Qc/HR) were determined in duplicate at 50 W and at 60% of VO2max on two different days both before and after training.

RESULTS

After training, there were significant decreases in HR and Qc, and significant increases in SV and a-vO2 diff at 50 W (except for no change in a-vO2 diff in black men). The changes in HR differed by sex and age, and the changes in SV, Qc, and a-vO2 diff differed by race. Qc decreased by 0.6 L x min(-1) at 50 W for the total sample, consistent with the decrease in VO2 at this power output. At 60% of VO2max HR decreased, and SV, Q, and a-VO2 diff increased. There were small differences in response by sex (HR and SV), race (HR), and age (HR and Qc).

CONCLUSION

It is concluded that the cardiovascular systems of men and women, blacks and whites, and younger and older subjects are not limited in their ability to adapt to endurance training.

NOS3 Glu298Asp genotype and blood pressure response to endurance training: the HERITAGE family study

Endothelium-dependent vasodilation is a mechanism that may affect blood pressure response to endurance training. Because NO plays a central role in this process, the endothelial NO synthase gene is a good candidate for the regulation of exercise blood pressure. We investigated the associations between an endothelial NO synthase gene polymorphism (Glu298Asp) and endurance training-induced changes in resting and submaximal exercise blood pressure in 471 white subjects of the HERITAGE Family Study. Two submaximal exercise tests at 50 W were conducted both before and after a 20-week endurance training program. Steady-state exercise blood pressure was measured twice in each test with an automated unit. The Glu298Asp polymorphism was typed with a PCR-based method and digestion with BAN:II. Both systolic and diastolic blood pressure at 50 W decreased in response to the training program, whereas resting blood pressure remained unchanged. The decrease in diastolic blood pressure at 50 W was greater (P=0.0005, adjusted for age, gender, baseline body mass index, and baseline diastolic blood pressure at 50 W) in the Glu/Glu homozygotes (4.4 [SEM 0.4] mm Hg, n=187) than in the heterozygotes (3.1 [0.4] mm Hg, n=213) and the Asp/Asp homozygotes (1.3 [0.7] mm Hg, n=71). The genotype accounted for 2.3% of the variance in diastolic blood pressure at 50 W training response. Both the Glu298 homozygotes and the heterozygotes had a greater (P=0.013) training-induced reduction in rate-pressure product at 50 W than the Asp298 homozygotes. These data suggest that DNA sequence variation in the endothelial NO synthase gene locus is associated with the endurance training-induced decreases in submaximal exercise diastolic blood pressure and rate-pressure product in sedentary normotensive white subjects.

[External contour acquisition system for radiotherapy: an original solution]

A contour acquisition system has been designed in radiotherapy at the Sagamie Hospital complex (Chicoutimi, Québec) to measure the external contours of the patients who do not need a CT exam. This measuring system can produce transversal, sagittal or coronal patient contours in the treatment position. The absolute accuracy of the system is +/- 1 mm. The contours produced by this equipment can be transferred electronically or on paper to the planning system.

Familial aggregation of stroke volume and cardiac output during submaximal exercise: the HERITAGE Family Study

Familial aggregation of stroke volume (SV) and cardiac output (Qc by CO2 rebreathing) at 50 Watts (W) and 60 % of maximal oxygen uptake (VO2max) as well as their changes in response to a 20-week endurance exercise training program was assessed in 99 Caucasian families who participated in the HERITAGE Family Study. In order to interpret familial influences independent of effects of age, sex, and body size (indexed by body surface area here), SV and Qc levels were adjusted for these primary parameters prior to genetic analysis within four sex-by-generation groups (the responses to training were additionally adjusted for their baseline values). Maximal heritabilities for baseline SV, Qc, and their changes in response to training during the two stages of submaximal exercise were estimated using a familial correlation model. At 50W, maximal heritabilities reached 41% and 42% for baseline SV and Qc, respectively, and were 29% and 38% for the respective responses to training. At 60% of VO2max, maximal heritabilities reached 46 % for baseline SV and Qc, and were 24% and 30% for the respective responses to training. Generally there were no meaningful differences between the maximal heritabilities at 50 W and 60% of VO2max. However, the maximal heritabilities for the baseline were slightly higher than the estimates for the changes in response to training. Based upon results arising from these non-obese, non-hypertensive, and sedentary families, we found that SV and Qc at 50 W and 60% of VO2max as well as their changes in response to the 20-week endurance exercise training were moderately heritable. Not only genetic determinants but also familial non-genetic factors might attribute to the observed patterns of familial aggregation of SV and Qc during submaximal exercise in the present study.

The SepOvotropin: a new ovarian peptide regulating oocyte transport in Sepia officinalis

In the cuttlefish Sepia officinalis, the successive steps of egg laying are controlled by multiple neuropeptides. Recent experiments led us to suppose that there was possible involvement of a second regulation pathway by the release of ovarian regulatory peptides in the genital tract. Using HPLC fractionation and an in vitro biological test, a C-terminal amidated peptide modulating the motility of the Sepia officinalis oviduct was isolated from an extract of vitellogenic ovarian follicles. The mass of this peptide as determined by MALDI-TOF (1501.8 Da) and analysis by Edman degradation led to the following sequence: Pro-Lys-Asp-Ser-Met-Leu-Leu-Leu-Gln-Val-Pro-Val-Tyr-amide. The peptide mapping performed by LC/MS revealed a distribution restricted to the follicles, the full grown oocytes and the eggs. This new peptide, called SepOvotropin, modulated contractions of the whole genital tract in physiological conditions from a threshold concentration between 10(-20) and 10(-19) M, demonstrating for the first time the occurrence of a specific peptidergic control of egg-laying in cephalopods.

A polymorphism in the alpha2a-adrenoceptor gene and endurance athlete status

PURPOSE

In a case control study, we examined the allelic frequencies and genotype distributions of two restricted fragment length polymorphisms (RFLP) in the alpha-2A-adrenoceptor gene (ADRA2A) and beta-2-adrenoceptor gene (ADRB2) among elite endurance athletes (EEA) and sedentary controls (SC).

METHODS

The EEA group included 148 Caucasian male subjects recruited on the basis that they had a VO2max > 74 mL O2 x kg(-1) x min(-1). The SC group comprised 149 unrelated sedentary male subjects, all Caucasians, from the Quebec Family Study. After digestion with the restriction enzymes Dra I (ADRA2A) and Ban I (ADRB2), Southern blotting and hybridization techniques were used to detect the mutations in the two ADR genes, which are encoded on chromosomes 10 (q24-26) and 5 (q31-32), respectively.

RESULTS

For the Dra I ADRA2A RFLP, we observed a significant difference in genotype distributions between the two groups (P = 0.037). A higher frequency of the 6.7-kb allele was observed in the EEA group compared with the SC group (P = 0.013). No statistically significant difference was found between groups for the Ban I ADRB2 polymorphic site. Genotype frequencies for both genes in both groups were in Hardy-Weinberg equilibrium.

CONCLUSIONS

In summary, we found evidence that ADRA2A gene variability detected with Dra I is weakly associated with elite endurance athlete status, and we conclude that genetic variation in the ADRA2A gene or a locus in close proximity may play a role in being able to sustain the endurance training regimen necessary to attain a high level of maximal aerobic power.

ILME: a waterborne pheromonal peptide released by the eggs of Sepia officinalis

A novel tetrapeptide modulating the oviduct contractions was characterized from egg mass of Sepia officinalis. After two purification steps by rpHPLC, an apparent pure fraction containing the biological activity was submitted to MALDI-TOF analysis. The mass spectrum revealed 6 peaks of m/z 293, 505, 596, 613, 728, and 745. The tissue peptide mapping performed in LC-MS demonstrated the occurrence of the m/z 505 peptide in the follicles, the full-grown oocytes, and in the eggs. This peptide was also recovered in the seawater after the incubation of full grown oocytes or eggs, demonstrating a release in the genital tract and in the environment. Edman degradation gave the following sequence: Ileu-Leu-Met-Glu. The synthetic peptide applied to the whole genital tract triggered a cyclisation of the contractions at 10(-14) M. ILME appeared to be a chemical messenger released by the oocytes and the eggs, and was able to exert both paracrine and pheromonal activity.

A genetic study of sex hormone--binding globulin measured before and after a 20-week endurance exercise training program: the HERITAGE Family Study

Familial aggregation and a major gene effect were assessed for baseline serum sex hormone-binding globulin (SHBG) levels and the response (post-training minus baseline) to a 20-week endurance training program in a selected sample of 428 non-obese nonhypertensive individuals from 99 white families who were sedentary at baseline in the HERITAGE Family Study. Baseline SHBG levels were not normally distributed, and were therefore logarithmically transformed prior to genetic analyses. In a sample without postmenopausal mothers, maximal (genetic and familial environmental) heritabilities were 50% averaged across sexes, 73% in men, 50% in women, and 31% in men versus women for the age-body mass index (BMI)-adjusted baseline. The estimate reached 64% when the baseline was further adjusted for the effects of estradiol, fasting insulin, and testosterone levels. For the response to training, no sex difference was found and the heritability reached about 25% to 32%. Segregation analysis was separately performed in the whole sample and in the sample without postmenopausal mothers. In addition to a multifactorial effect for both the baseline and the response to training, a major effect for the baseline appeared to be familial environmental in origin, whereas a major effect for the response to training was Mendelian in nature. The major gene effect for the response to training in the whole sample was undetectable in the sample without postmenopausal mothers, and it is therefore possible that the postmenopausal mothers, characterized by decreased sex hormones with or without estrogen replacement therapy for menopause, produced some confounding effects. In addition, the reduced sample size might also be a plausible candidate explanation. The novel finding in this study is that baseline SHBG levels and the response to training were influenced by a multifactorial effect with sex difference for the baseline. The response to training appeared to be additionally influenced by a single recessive locus that is independent of baseline SHBG levels.

Race, visceral adipose tissue, plasma lipids, and lipoprotein lipase activity in men and women: the Health, Risk Factors, Exercise Training, and Genetics (HERITAGE) family study

Abdominal obesity is associated with numerous metabolic alterations, such as hypertriglyceridemia and low levels of high density lipoprotein (HDL) cholesterol. However, compared with abdominally obese white individuals, abdominally obese black individuals have been characterized by higher plasma HDL cholesterol levels, suggesting that the impact of abdominal fat accumulation on the lipoprotein-lipid profile may differ among ethnic groups. Therefore, we have compared the associations between body fatness, visceral adipose tissue (AT) accumulation, and metabolic risk variables in a sample of 247 white men and 240 white women versus a sample of 93 black men and 143 black women. Although no difference in mean total body fatness was found between the 2 race groups, white men had higher levels of visceral AT than did black men (P<0.001). Despite the fact that black women had a greater body fat content than did white women, black women had levels of visceral AT that were similar to those of white women, suggesting a lower susceptibility to visceral obesity in black women. This lower accumulation of visceral AT in blacks was accompanied by significantly reduced apolipoprotein B concentrations and ratios of total cholesterol to HDL cholesterol as well as higher plasma HDL cholesterol levels (P<0.05) compared with those values in whites. Irrespective of sex, higher postheparin plasma hepatic lipase (HL) and lower lipoprotein lipase (LPL) activities were found in whites, resulting in an HL/LPL ratio that was twice as high in whites as in blacks (P<0.005). Although differences in lipoprotein-lipid levels were noted between whites and blacks, results from multiple regression analyses revealed that after control for morphometric and metabolic variables of the study (body fat mass, visceral AT, LPL, HL, and age), ethnicity had, per se, only a minor contribution to the variance in plasma lipoprotein levels. Thus, our results suggest that the higher plasma HDL cholesterol levels and the generally more cardioprotective plasma lipoprotein profile found in abdominally obese black versus white individuals are explained, at least to a certain extent, by a lower visceral AT deposition and a higher plasma LPL activity in black individuals.

Familiality of triglyceride and LPL response to exercise training: the HERITAGE study

PURPOSE

The main purpose of the present investigation was to test whether and to what extent familial/genetic factors are involved in the changes of postheparin lipoprotein lipase (deltaPH-LPL) activity and triglyceride (deltaTG) levels in response to exercise training. Additional hypotheses were also tested as to whether there were familial/genetic factors shared by baseline and the corresponding response to exercise training (i.e., by baseline triglyceride (TG(B)) and deltaTG and by baseline postheparin lipoprotein lipase (PH-LPL(B)) and deltaPH-LPL activity).

METHODS

Serum TG and PH-LPL were measured in 459 subjects from 99 sedentary Caucasian families of the HERITAGE Family study before (baseline) and after completing a 20 wk (3 times per week) exercise training protocol. The training protocol had a target intensity of 75% of the heart rate associated with baseline VO2max during the last 6 wk. PH-LPL activity was measured in the study subjects. Both univariate and bivariate familial correlation analyses were applied to the baseline and response data.

RESULTS

The maximal heritabilities for deltaTG and deltaPH-LPL activity were 22% and 15%, respectively. There were no common familial factors for TG(B) and deltaTG, nor were there any for PH-LPL(B) and deltaPH-LPL. However, we found that there were common familial factors underlying deltaTG and deltaPH-LPL; these familial factors seemed to differ across sex and generation groups.

CONCLUSION

Although there were no common familial factors underlying the covariation between the baseline triglyceride and PH-LPL activity and the corresponding responses to exercise training (i.e., TG(B) with deltaTG or PH-LPL(B) with deltaPH-LPL), the deltaTG and deltaPH-LPL covariation apparently share some common familial determinants.

AGT M235T and ACE ID polymorphisms and exercise blood pressure in the HERITAGE Family Study

We investigated the association between angiotensinogen (AGT) and angiotensin-converting enzyme (ACE) gene polymorphisms and exercise training responses of resting and exercise blood pressure (BP). BP at rest and during submaximal (50 watts) and maximal exercise tests was measured before and after 20 wk of endurance training in 476 sedentary normotensive Caucasian subjects from 99 families. AGT M235T and ACE insertion/deletion polymorphisms were typed with PCR-based methods. Men carrying the AGT MM and MT genotypes showed 3. 7 +/- 0.6 and 3.2 +/- 0.5 (SE) mmHg reductions, respectively, in diastolic BP at 50 watts (DBP(50)), whereas, in the TT homozygotes, the decrease was 0.4 +/- 1.0 mmHg (P = 0.016 for trend, adjusted for age, body mass index, and baseline DBP(50)). Men with the ACE DD genotype showed a slightly greater decrease in DBP(50) (4.4 +/- 0.6 mmHg) than the II and ID genotypes (2.8 +/- 0.7 and 2.4 +/- 0.5 mmHg, respectively, P = 0.050). Furthermore, a significant (P = 0.022) interaction effect between the AGT and ACE genes was noted for DBP(50); the AGT TT homozygotes carrying the ACE D allele showed no response to training. Men with the AGT TT genotype had greater (P = 0.007) diastolic BP (DBP) response to acute maximal exercise at baseline. However, the difference disappeared after the training period. No associations were found in women. These data suggest that, in men, the genetic variation in the AGT locus modifies the responsiveness of submaximal exercise DBP to endurance training, and interactions between the AGT and ACE loci can alter this response.

Reproducibility of resting blood pressure and heart rate measurements. The HERITAGE Family Study

PURPOSE

This study determined the reproducibility of resting systolic and diastolic blood pressure, mean arterial pressure, and heart rate (the average of three measures/day).

METHODS

The data were obtained on two separate days prior to an exercise training intervention in a sample of 822 subjects participating in the HERITAGE Family Study. The same protocol was conducted across three days in an intracenter quality control substudy, which included an additional 60 subjects.

RESULTS

Reproducibility estimates included technical error, coefficient of variation within subjects, and intraclass correlation with results expressed by sex, race, age, cuff size, BMI, and %fat. Since the data were collected across four Clinical Centers, the reproducibility estimates were also computed separately for each Center. The systolic, diastolic, and mean arterial blood pressures were highly reproducible with technical errors less than 5.1 mmHg, coefficients of variation of less than 7. 0% and intraclass correlations > 0.75. The heart rates were slightly less reproducible. These results were fairly consistent across subject populations and across all four Clinical Centers.

CONCLUSION

It is concluded that within subject day-to-day variations are small compared to between subject variance for resting systolic, diastolic, and mean arterial blood pressure and heart rate at each of the Clinical Centers for all of the HERITAGE Family Study data. This makes it appropriate to pool the data and analyze it for changes subsequent to endurance exercise training and to determine the possible genetic basis for these changes.