The combined method to determine VT is valid and reliable across a wide fitness range in healthy individuals and improves the determination rate and accuracy of VT determination over the use of single methods.

Background:Spinal muscular atrophy (SMA) is the most common inherited lethal disease of children. Various genetic deletions involving the bi-allelic loss of SMN1 exon 7 are reported to account for 94% of affected individuals. Published literature places the carrier frequency for SMN1 mutations between 1 in 25 and 1 in 50 in the general population. Although SMA is considered to be a pan-ethnic disease, carrier frequencies for many ethnicities, including most ethnic groups in North America, are unknown.Objectives and methods:To provide an accurate assessment of SMN1 mutation carrier frequencies in African American, Ashkenazi Jewish, Asian, Caucasian, and Hispanic populations, more than 1000 specimens in each ethnic group were tested using a clinically validated, quantitative real-time polymerase chain reaction (PCR) assay that measures exon 7 copy number.Results:The observed one-copy genotype frequency was 1 in 37 (2.7%) in Caucasian, 1 in 46 (2.2%) in Ashkenazi Jew, 1 in 56 (1.8%) in Asian, 1 in 91 (1.1%) in African American, and 1 in 125 (0.8%) in Hispanic specimens. Additionally, an unusually high frequency of alleles with multiple copies of SMN1 was identified in the African American group (27% compared to 3.3–8.1%). This latter finding has clinical implications for providing accurate adjusted genetic risk assessments to the African American population.Conclusions:Differences in the frequency of SMA carriers were significant among several ethnic groups. This study provides an accurate assessment of allele frequencies and estimates of adjusted genetic risk that were previously unavailable to clinicians and patients considering testing.

1) Training intensity (relative to VT) accounting for about 26% of the improvement in VO2vt (R2 = 0.26, p < 0.0001). 2) The absolute intensity of training in watts (W) accounted for approximately 56% of the training effect at VT (R2 = 0.56, p < 0.0001) with post-training watts at VT (VT(watts)) being not significantly different than W during training (p > 0.70). 3) Training intensity (relative to VT) had no effect on DeltaVO2max. These data clearly show that as a result of aerobic training both the VO2 and W associated with VT respond and become similar to the absolute intensity of sustained (3 x /week for 50 min) aerobic exercise training. Higher intensities of exercise, relative to VT, result in larger gains in VO2vt but not in VO2max.

Recently published evidence from two large-scale clinical trials conducted in England and in Denmark suggests that faecal occult blood screening for colorectal cancer significantly reduces mortality. However, before screening can be advocated as part of national health policy, its cost-effectiveness must be demonstrated. The English screening trial has been the subject of a detailed economic evaluation over the past 10 years In this paper, cost-effectiveness estimates of screening are presented, based on cost and outcome data combined in a mathematical model developed from the trial's clinical findings The estimates of cost per quality-adjusted life-year gained from colorectal cancer screening show the procedure to be of similar cost-effectiveness to breast cancer screening in the short term. Over the longer term, however, the estimates for colorectal cancer screening appear superior.

The purpose of the present study was to assess possible racial differences in cardiovascular and plasma catecholamine responses to dynamic exercise. A biracial group of normotensive college-age men (15 blacks, 15 whites) were tested for maximal oxygen uptake, resting blood pressure, and heart rate. Subjects then rode a cycle ergometer at 25%, 50%, and 75% of peak oxygen uptake (6 minutes at each stage). Blood pressure and heart rate were measured during supine rest, seated rest, and at each stage of exercise with an automated blood pressure monitor. At each stage, venous blood was sampled to allow determination of plasma norepinephrine and epinephrine, and cardiac output was measured with the carbon dioxide rebreathing technique. The results indicated that resting blood pressure was similar for blacks and whites (114/68 versus 115/68 mm Hg, respectively). Blacks exhibited greater systolic and diastolic blood pressures during submaximal dynamic exercise. However, blacks also showed a trend toward a positive parental history of hypertension, which has been associated with an increased pressor response. Racial differences did not exist for heart rate or cardiac output, but blacks had higher values for total peripheral resistance both at rest and during exercise. Although no overall racial differences were seen for plasma catecholamine concentrations at rest, blacks had significantly lower levels of norepinephrine (1,275 versus 1,556 pg/ml) and higher levels of epinephrine (306 versus 216 pg/ml) than whites at the highest work rate. The current study confirms the increased pressor response to exercise in normotensive blacks. Blacks had an elevation in total peripheral resistance that was not accompanied by an increase in plasma norepinephrine levels.

This study was performed to determine whether alterations in vascular structure exist in a biracial population of young (age 22.3 +/- 0.6 yrs [mean + SE]) normotensive men. We examined maximal vasodilatory capacity in 21 blacks and 20 whites (average blood pressure = 122/75 and 118/72 mm Hg, respectively). Forearm blood flow was determined at rest and after 10 min of ischemic handgrip exercise using venous occlusion plethysmography. Forearm vascular resistance was computed from blood flow and mean arterial blood pressure determined by auscultation. Minimum forearm vascular resistance was 23% higher in blacks (2.60 +/- 0.60) than in whites (2.11 +/- 0.41) (P = .005), and was unrelated to parental history of hypertension. The regression equation for minimum forearm vascular resistance (Y) and casual blood pressure (X) for blacks was Y = -1.782 + 0.0487X (r = 0.522); for whites it was Y = -1.165 + 0.0367X (r = 0.418). When the data were covaried on resting mean arterial blood pressure, blacks still had a higher minimum forearm vascular resistance (P = .014). The results suggest a racial difference in the vascular structure of the forearm resistance vessels.

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