Speed of color naming and degree of familial sinistrality: correlation in girls, no correlation in boys

Twenty-nine male and 35 female right-handed children, aged 5 to 7, were assessed for the effect of familial sinistrality on a rapid color-naming task. Controlling for age and family size, a significant effect for degree of familial sinistrality was found in the girls but not in the boys. Among the girls, those with two or more left-handed or ambidextral relatives were the fastest on the color-naming task, those with no such relatives were the slowest, and those with only one left-handed or ambidextral relative scored between the other two groups in color-naming speed. It is suggested that a gene associated with left-handedness, when present in a right-hander, interacts with sex to produce the superior color-naming performance that we observed in girls but not in boys.     

Intussusception as a late morbidity after gastroschisis repair

A 4-month-old boy presented with intussusception following primary closure of a gastroschisis as a neonate. Hydrostatic reduction of the intussusception was successful. After the reduction an ileus persisted for several days, but was successfully managed conservatively. As far as we know, this is the first report of a gastroschisis patient developing an intussusception. The diagnosis of intussusception per se was not difficult, but itwas difficult to rule out a midgut volvulus, which would have required an urgent laparotomy.Presented at the New Zealand Annual Scientific Meeting of Royal Australasian College of Surgeons, Palmerston North, August 10, 1994     

The relationship between endogenous testosterone and gonadotrophin secretion

OBJECTIVE The secretion of luteinizing hormone (LH), follicle stimulating hormone (FSH) and testosterone in the adult male was studied by means of 48-hour profiles. The aim of the study was to examine the effects of the endogenous circadian variation in serum testosterone concentration on LH pulsatility, and to determine the temporal relationships between FSH and LH, and between LH and testosterone by cross-correlation, and the pulse frequency of these hormones by spectral analysis, as revealed by extended sampling periods. DESIGN Hormone profiles were obtained by 20-minute sampling over 48 hours. SUBJECTS Six healthy adult males, aged between 21 and 23 years. MEASUREMENTS LH and FSH were measured using an immunoradiometric assay and testosterone with a solid-phase radioimmunoassay. RESULTS The profiles showed pulsatile secretion of all three hormones, and a circadian rhythm with levels highest between 0200 and 0600 h. Cross-correlation analysis There was a significant relationship between LH and FSH (r= 0.5; P=0.001) at 0 minutes (i.e. no time lag). A pulse of testosterone followed on average 60 minutes after a pulse of LH (r= 0.28; P= 0.001). Fourier transformation Spectral analysis showed the dominant period for LH and FSH pulsatility to be 200 minutes. The dominant period for testosterone pulsatility was 400 minutes. The effect of endogenous variations in serum testosterone concentrations The LH profiles were divided into periods when the serum testosterone concentration was high or low, and Fourier transformation carried out on these shorter periods. These transforms showed that the dominant period during high serum testosterone concentration was 180 minutes, and during low serum testosterone was 120 minutes (P ± 0.025). CONCLUSIONS FSH and LH are co-secreted, and a pulse of testosterone follows a pulse of LH by 60 minutes. The physiological changes in serum testosterone concentration that occur during the day result in changes in the pulse frequency of LH. Testosterone concentrations thus have rapidly acting feedback activity at hypothalamic level.