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SKINNER, J. S., S. E. GASKILL, T. RANKINEN, A. S. LEON, D. C. RAO, J. H. WILMORE, and C. BOUCHARD. Heart Rate versus %V̇O2max: Age, Sex, Race, Initial Fitness, and Training Response—HERITAGE. Med. Sci. Sports Exerc., Vol. 35, No. 11, pp. 1908–1913, 2003. Purpose In the HERITAGE Family Study, heart rate (HR) associated with various percentages of maximal oxygen intake (V̇O2max) was used to prescribe exercise intensity. When fitness improved, HR at the same power output (PO) decreased, and PO was increased to produce the prescribed HR. Although we assumed that subjects were again working at the same %V̇O2max, there were no studies with a large heterogeneous population to determine whether this was correct. Methods Therefore, 653 subjects with complete data were classified by age, sex, race, initial V̇O2max, and V̇O2max response after 20 wk of training. Results All groups had a significant increase in V̇O2max and a significant decrease in HR at the same absolute PO after training but no difference in HR at the same relative intensity. Conclusions Training does not affect HR at a given %V̇O2max in a heterogeneous population of men and women, blacks and whites aged 17–65 yr with different initial V̇O2max values and different responses to training.

No abstract is provided for this article.

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PURPOSE: Recently published work by our group identified mitochondrial DNA (mtDNA) variants and heteroplasmy that differ between individuals categorized by high and low aerobic capacity (VO2max) trainability, part of the HERITAGE Family Study Cohort. Our purpose in this investigation was to assess insertions and deletions (indels) in mitochondrial genomes in high (HR) and low responders (LR). METHODS: DNA was isolated from whole blood in HERITAGE Family Study healthy subjects (subjects classified by change in VO2max: HR: n = 15; LR: n = 15). mtDNA was amplified by long-range polymerase chain reaction, then tagged with Nextera libraries, and sequenced on a Miseq instrument. An indel was defined as an insertion or deletion with a frequency of at least 1% at a specific location. For this study, we compared indel sites and the frequency they occurred between HR and LRs. RESULTS: Among subjects, we identified 11 total sites where an indel occurred in at least one individual: mtHVR2 (C285CA: LR = 1 individual; HR = 0 individuals), mtHVR2 (A302AC: LR = 1 individual; HR = 0 individuals), mtHVR3 (G513GCA: LR = 1 individual; HR = 1 individual), mtHVR3 (GCA513G: LR = 3 individuals; HR = 1 individual), mtHVR3 (A567AC: LR = 0 individuals; HR = 1 individual), mtND4 (GA11031G: LR = 0 individuals; HR = 1 individual), mtND5 (CA12417C: LR = 11 individuals; HR = 8 individuals), mtHVR1(CA16179C: LR = 0 individuals; HR = 2 individuals), mtHVR1 (A16182AC: LR = 0 individuals; HR = 2 individuals), mtHVR1 (CT16188C: LR = 0 individuals; HR = 3 individuals), mtHVR1(C16192CT: LR = 0 individual; HR = 1 individual). The average total frequency across the indels in LR was 41.32 % (± 43.55 %) and 31.59 % (± 33.29 %) in HRs. We identified three sites with indels that were present in HR but not LR: mtHVR1 (CA16179C; 21.5% ± 0.71% mean indel frequency), mtHVR1 (A16182AC; 13.4% ± 0.57% mean indel frequency), and mtHVR1 (CT16188C; 17.4% ± 21.45% mean indel frequency). CONCLUSIONS: We found three sites with indels in the HVR1 region of the mitochondrial genome in HR but not LR. While our sample size is small, our findings highlight an area of the mitochondrial genome that is responsible for mtDNA replication that presents indels in individuals classified by low trainability. Our on-going work is to increase the sample size and assess indel implications on VO2max trainability.

En el actual contexto penitenciario de lucha contra la desocializacion, las asociaciones ofrecen apoyo psicologico y social a las familias de los presos. La investigacion-accion «Regards d’enfants sur l’incarceration» («Miradas de ninos sobre el encarcelamiento») de la que se informa en este articulo, realizada en colaboracion con dos de esas asociaciones, consiste en la creacion de grupos de apoyo para los ninos que tienen a uno de sus padres o un ser querido en prision. El objetivo de esta investigacion-accion es evaluar las condiciones, los medios y las herramientas que permitirian ofrecer una oportunidad de intercambio a los ninos para compartir sus experiencias y expresar lo que no se puede decir a los padres, a los seres queridos y a su entorno social (amigos, escuela, vecinos, etc.). Los resultados confirman la evidente necesidad de reforzar las practicas profesionales en torno a las familias, en particular a los ninos, que son los grandes ausentes en nuestros dispositivos de asistencia en Francia.

Central (intracerebral ventral) and peripheral (subcutaneous and intraperitoneal) administration of ghrelin causes obesity in rodents by increasing food intake and decreasing fat oxidation. Recent studies in humans have shown that plasma ghrelin concentration was inversely related to body fat and was lower in Pima Indians, a population susceptible to obesity. Whether ghrelin plays a role in the etiology of obesity in humans is unknown. We, therefore, measured plasma ghrelin concentration before and after two interventions in monozygotic twins previously studied at Laval University, Quebec City. Twelve pairs of monozygotic twins were overfed by 84,000 kcal over a 100-day period, whereas another seven pairs of monozygotic twins were submitted to a 53,000 kcal negative energy balance induced by exercise over a 93-day period. At baseline, for all the subjects, plasma ghrelin concentration was negatively correlated with body mass and body fatness (r varying from 0.36 to 0.45). The intraclass coefficient for the twin resemblance (r(I) = 0.75; p = 0.006) indicated that plasma ghrelin concentration is a familial trait. In response to the 100-day intervention, plasma ghrelin exhibited a non-significant decrease of 61 +/- 30 fmol/l (p = 0.18) with overfeeding and a non-significant increase of 58 +/- 34 fmol/l (p = 0.17) with negative energy balance. However, there was no relationship between baseline plasma ghrelin concentration and the magnitude of body weight change in both interventions. These first experimental data under "clamped energy balance conditions" do not provide evidence that plasma ghrelin is involved in the etiology of human obesity. However, studies in free-living individuals are needed to clarify this question.

No abstract is provided for this article.

—Complex segregation analyses of apolipoproteins (apo) A-1 and B-100 were performed in a sample of 520 individuals from 99 white families who participated in the HERITAGE Family Study. In these sedentary families, plasma apo A-1 and B-100 concentrations were measured before and after a 20-week endurance exercise training program. Baseline apo A-1 and B-100 were adjusted for the effects of age (age-adjusted baseline apo A-1 and B-100) and for the effects of age and BMI (age-BMI–adjusted baseline apo A-1 and B-100). The change in response to training was computed as a simple Δ (posttraining minus baseline) and was adjusted for age and the baseline (age-baseline–adjusted apo A-1 and B-100 responses to training). In the present study, a major gene could not be inferred for baseline apo A-1. Rather, we found a major effect along with a multifactorial effect accounting for 8% to 9% and 51% to 56% of the variance, respectively. In addition, no clear evidence supported a major-gene effect for its response to training, whereas the transmission of a major effect from parents to offspring was ambiguous, ie, genetic in nature or familial environmental in origin. The major effect accounted for 15% of the variance, with an additional 21% and 58% of the variance being accounted for by a multifactorial effect in parents and offspring, respectively. It is interesting to have obtained evidence of a putative recessive major locus for baseline apo B-100, which accounted for 50% to 56% of the variance, with an additional 25% to 29% of the variance due to a multifactorial effect. In contrast, no major effect for its response to training was identified, although a multifactorial effect was found that accounted for 27% of the variance. The novel findings arising from the present study are summarized as follows. Baseline apo A-1 and its response to training were influenced by a major effect and a multifactorial effect. Baseline apo B-100 was influenced by a putative major recessive gene with a multifactorial component, but its response to training was influenced solely by a multifactorial component in these sedentary families.

Aims To test for associations between type 2 diabetes mellitus (T2DM)-related traits and polymorphisms (SNPs) in the hepatocyte nuclear factor 4-α gene (HNF4A) in the Quebec Family Study cohort, and determine whether these associations are modulated by physical activity (PA). Methods Two HNF4A SNPs (rs1885088 G>A; rs745975 C>T), previously reported to be associated with T2DM, were studied in 528 non-diabetic subjects who underwent a 75g oral glucose tolerance test (OGTT). Glucose, insulin and C-peptide plasma levels, measured in the fasting state and during the OGTT, were used in the analysis. The amount (hours per week) of PA was assessed by questionnaire. Results The HNF4A rs1885088 SNP was not independently associated with T2DM-related traits, whereas the rs745975 was associated with fasting insulin, HOMA-IR and 2-h glucose levels (p <0.05 for all). Genotype by PA interactions were found for glucose homeostasis (p <0.0001) and insulin secretion (p ≤0.03). When subjects were stratified by PA level (according to the median value), we found that high level of PA (>2h/week) was associated with smaller glucose area under the curve (AUC) and 2-h glucose levels in rs1885088 A/A homozygotes and with lower fasting C-peptide and insulin AUC in rs745975 T/T homozygotes. Conclusion These results indicate that the associations of HNF4A rs1885088 with glucose tolerance and rs745975 with insulin secretion are modulated by PA. Our finding therefore suggests that the effect of HNF4A polymorphisms on the risk of T2DM is influenced by PA.