To increase the range resolution in ISAR imaging radar, time adaptations of the MUSIC algorithm and of Capon MLM are applied on each azimuth bin. The covariance matrix of each azimuth bin is estimated from the corresponding azimuth bin of ISAR images made with different carrier frequencies to avoid cross-correlation between scatterers. Simulation results are shown as well as some preliminary measurement processings.
The objective of the current study was to examine the potential impact of a cryptic trinucleotide repeat polymorphism in exon 3 of proopiomelanocortin (POMC) on serum leptin levels and salivary cortisol, as well as obesity and estimates of insulin, glucose, and lipid metabolism in 284 unrelated Swedish men born in 1944. Moreover, we examined if a single nucleotide polymorphism (SNP) (C[rarr ]T) in exon 3 was associated with these characteristics. The amplification of the microsatellite locus yielded a 155-bp fragment and a fragment with one additional copy of the 9-bp repeat unit GGCAGCAGC (164 bp). The allelic frequencies were 0.96 and 0.04, respectively. Tests for differences in phenotype showed that subjects with the longer polymerase chain reaction (PCR) repeat product (n = 21) had significantly higher serum leptin concentrations (P = .024) compared with subjects with the shorter PCR product (n = 230). Salivary cortisol levels, as well as obesity and its related metabolic perturbations, were the same across the POMC genotypes. In conclusion, a microsatellite polymorphism in exon 3 of POMC is associated with elevated serum leptin levels. This association might reflect variations in melanocortin expression and/or activity, because exon 3 contains, among others, the coding sequences for melanocortins.
GASKILL, S. E., T. RICE, C. BOUCHARD, J. GAGNON, D. C. RAO, J. S. SKINNER, J. H. WILMORE, and A. S. LEON. Familial resemblance in ventilatory threshold: the HERITAGE Family Study. Med. Sci. Sports Exerc., Vol. 33, No. 11, 2001, pp. 1832–1840. Purpose: This study investigates the familial resemblance of V̇O2 at the ventilatory threshold (V̇O2vt) from 199 nuclear families (100 White and 99 Black) participating in the HERITAGE Family Study. Methods: V̇O2vt (mL·min−1) was determined in the sedentary state and again after 20 wk of aerobic cycle ergometer exercise training in 339 individuals (131 parents and 228 of their offspring), aged between 17 and 65 yr. V̇O2vt was adjusted for weight, age, fat mass, and fat-free mass by using regression methods. Results: There was evidence for significant familial resemblance in the sedentary state for V̇O2vt (maximal heritability = 58% in White and 54% in Black families) and V̇O2vt/V̇O2max (maximal heritability = 38% in White and 39% in Black families). Spouse, sibling, and parent-offspring relationships for V̇O2vt were significant at baseline, suggesting that both genetic and shared environmental factors may contribute to the familial resemblance in the sedentary state. There was a moderate familial component in the response of V̇O2vt to aerobic exercise training in Whites (22%) and a larger component in Blacks (51%). In Blacks, the familial effect for V̇O2vt/V̇O2max appeared to be accounted for by fat and fat-free mass. Conclusion: These results show a strong familial contribution to V̇O2vt in the sedentary state and to the response of V̇O2vt to aerobic exercise training.
The aims of the present study were to confirm the modulation by 5‐HT 3 receptors of the electrically evoked release of tritium from slices preloaded with [ 3 H]‐5‐HT of guinea‐pig frontal cortex, hippocampus and hypothalamus, and to assess their functional role in 5‐HT release. The selective 5‐HT 3 agonist, 2‐methyl‐5‐HT, introduced 8 min before the electrical stimulation, enhanced in a concentration‐dependent manner the evoked release of [ 3 H]‐5‐HT in the three brain regions studied. The 5‐HT 3 agonists, phenylbiguanide and m ‐chlorophenyl‐biguanide, did not enhance the release of tritium in frontal cortex and hypothalamus slices. In hypothalamus slices, this response was lost when 2‐methyl‐5‐HT was introduced 20 min before the stimulation, thus indicating that these 5‐HT 3 receptors desensitize rapidly. When 2‐methyl‐5‐HT was added 20‐min before the first stimulation period to desensitize the 5‐HT 3 receptors, removed for 24 min, and then re‐introduced 8 min before the second stimulation period, the enhancing effect of 2‐methyl‐5‐HT was restored, thus indicating that these 5‐HT 3 receptors can rapidly regain normal sensitivity. The enhancing effect of 2‐methyl‐5‐HT was attenuated by the 5‐HT 3 receptor antagonists m ‐chloro‐phenylpiperazine = quipazine = ondansetron ≥ ICS 205–930 = BRL 24924 > MDL 72222 = zacopride. The 5‐HT reuptake blocker, paroxetine, enhanced the electrically evoked release of tritium when introduced 8 min before stimulation; this effect of paroxetine was blocked by ICS 205–930, thus indicating that these 5‐HT 3 receptors can be activated by endogenous 5‐HT. In the absence of electrical stimulation, 2‐methyl‐5‐HT (10 μ m ) produced a marked enhancement of the basal release of [ 3 H]‐5‐HT which was calcium‐dependent and blocked by S‐zacopride but not by paroxetine. The enhancing effect of 2‐methyl‐5‐HT was dependent both on the frequency of stimulation, as indicated by the attenuated effect of 120 stimulations delivered at 1 Hz instead of 5 Hz, and on the duration of the stimulation, as indicated by the more pronounced effect of pulses delivered at 5 Hz for 24 s instead of 72 s or 120 s.
The concept of individual differences in the response to exercise training or trainability was defined three decades ago. In a series of experimental studies with pairs of monozygotic twins, evidence was found in support of a strong genotype dependency of the ability to respond to regular exercise. In the HERITAGE Family Study, it was observed that the heritability of the maximal oxygen uptake response to 20 weeks of standardized exercise training reached 47% after adjustment for age, sex, baseline maximal oxygen uptake and baseline body mass and composition. Candidate gene studies have not yielded as many validated gene targets and variants as originally anticipated. Genome‐wide explorations have generated more convincing predictors of maximal oxygen uptake trainability. A genomic predictor score based on the number of favourable alleles carried at 21 single nucleotide polymorphisms appears to be able to identify low and high training response classes that differ by at least threefold. Combining transcriptomic and genomic technologies has also yielded highly promising results concerning the ability to predict trainability among sedentary people.
