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Heterotaxy syndromes, right or left atrial isomerism, result from disruption of left-right axis determination and their manifestations include complicated heart defects. Recent studies in model organisms have revealed complex genetic pathways and several genes involved in this process. In affected humans, however, molecular studies have identified mutations in a small number of individuals, while in most the cause remains unknown. Furthermore, although family data suggest, autosomal recessive inheritance, such genes have not yet been identified. We have studied six members of a family, four children affected with right atrial isomerism (RAI) and their healthy parents, for disturbances of left-right axis development. The children, one female and three males who all had complicated heart defects, succumbed and had an autopsy. Their nonconsanguineous parents were examined by cardiac and abdominal ultrasound or MRI. In all four children the heart defects included single ventricle with dysplastic atrioventricular (AV) valve, total anomalous pulmonary venous drainage (TAPVD), and malposition of great arteries (MGA) with pulmonary stenosis (PS). All had asplenia; two also had dextrocardia and abdominal situs inversus. The diagnosis of RAI was made postnatally in the first child and prenatally in others. Two siblings had no surgery and died as a newborn, one with obstructed supracardiac TAPVD and the other with regurgitating AV valve. Two children underwent heart surgery. One had repair of obstructive infracardiac TAPVD but died in infancy. The other underwent both hemi-Fontan operation and heart transplantation but died at the age of 2 years. This is the first report describing four children with RAI in the same family. The occurrence of RAI in male and female siblings without any indication of left-right axis abnormalities in their parents suggests autosomal recessive inheritance of human isomerism.

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We investigated the usefulness of peripheral blood pressure (BP) measurement in the assessment of strain in occupational physiology. Our hypothesis was that the brachial and peripheral BP reflect physiologically different events under various occupation-related demands in normotensive (NT) and hypertensive (HT) people. A group of 20 female and 20 male subjects with unmedicated mild hypertension that had been diagnosed by ambulatory blood pressure monitoring [awake time systolic/diastolic BP (BPs/BPd) 142.9 (SD 11.3)/86.4 (SD 6.2) mmHg] and 40 NT matched by age and sex [BPs/BPd 120.0 (SD 9.8)/75.6 (SD 5.9) mmHg] attended a laboratory session to undertake mental arithmetic tasks, a fingergrip test and submaximal cycle ergometry. Brachial and peripheral BP as well as heart rate were measured using a sphygmomanometer and an continuously automatic blood pressure measuring device on the finger, respectively. The peripheral BPs was higher than brachial BPs, BPd was similar for peripheral and brachial BP except during cycle ergometry. Associations between the levels of brachial and peripheral BP depended on demands and did not explain more than 42% of the common variance. The highest correlations between the two BP methods were observed during habituation, recovery and mental demands, and weak correlations during cycle ergometry. For peripheral BPs and BPd we found significant correlations in all phases of the test (r = 0.58 to 0.86, P < 0.001), also in ergometry (NT r = 0.62, P < 0.001, HT r = 0.53, P < 0.001), in contrast to the brachial BP. Peripheral BP differentiated the two BP groups (57.5%-72.5% correctly classified) which had been grouped by daily measurement of brachial BP, but brachial BP was superior in this respect with 65.0%-87.5% being correctly classified. These results supported the suggestion that the combined measurement of peripheral and brachial BP provides complementary information regarding physiological changes in NT and HT in different situations.

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Adrenomedullin is a peptide that induces pulmonary vasodilation in experimental animals. Adrenomedullin was measured in blood samples from cord artery and vein from 41 term newborns. In 23 of the newborns delivered vaginally, levels of adrenomedullin in the cord artery, 71.8+/-45.8 pg ml(-1) (mean +/- SD), and vein, 75.6+/-45.2 pg ml(-1), were significantly higher than in 18 newborns delivered by elective Caesarean section (40.7+/-14.6 pg ml(-1) and 32.4+/-10.3 pg ml(-1), respectively; both p < 0.01). A significant correlation existed between the concentration of adrenomedullin and pH in the cord artery (r = -0.545, p = 0.002). The fetus responds to birth stress by secreting high concentrations of adrenomedullin. As a potent vasodilator, the peptide may play a role in postnatal cardiovascular adaptation.

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