A prospective, randomized, cross-over comparison of two methods of artificial insemination by donor on the incidence of conception: intracervical insemination by straw versus cervical cap

In a prospective, randomized study of insemination with donor semen, intracervical insemination by straw was compared with insemination using a cervical cap with an intracervical reservoir. A total of 91 patients completed 486 treatment cycles. There were no significant differences in age, parity, indication for insemination by donor, or method of cycle monitoring between women who became pregnant and those who did not conceive with either insemination method. In 236 standard intracervical insemination cycles, 14 patients became pregnant (5.9% per cycle), whereas 38 patients conceived in 250 cervical cap cycles (15.2% per cycle). Both the crude pregnancy rates and the cumulative pregnancy rates calculated by the Kaplan-Meier life-table method were significantly different (chi(2)-test, P < 0.001, and log-rank test, P < 0.005 respectively). Pregnancy rates in artificial insemination with cryopreserved donor semen may be improved by the use of a cervical cap when compared to cervical insemination by straw. The use of the cervical cap may prolong the exposure of the spermatozoa to the cervical mucus and prevent the backflow of semen into the vagina.      

Left ventricular diastolic filling and cardiovascular functional capacity in older men

We investigated anaerobic threshold (< theta(L)) gas exchange kinetics and maximal oxygen uptake (VO2,max) among older men with reduced left ventricular end-diastolic filling (LVDF). Ten men (mean age, 73 years) with LVDF impairment and low fitness, but without other cardiovascular dysfunction were studied. Treatments compared to control included: 5 days, high intensity exercise training protocol; 5 days, calcium channel blockade (240 mg verapamil); 21 days, detraining/washout; and 5 days, combined treatments. Results indicated no changes in resting left ventricular systolic function with any treatment. Significant resting diastolic function changes included increased early:late flow velocity (control, 0.87; training, 1.28; verapamil, 1.32), and a decreased isovolumic relaxation time (control, 0.10 s; training, 0.08 s; verapamil, 0.08 s). The combined treatments were not additive. Sub-threshold oxygen uptake kinetics (tauVO2, s) were significantly faster following either training or verapamil (tauVO2,control, 62+/-12; tauVO2,training, 44+/-9; tauVO2,verapamil, 48+/-10) and combined treatments (tauVO2, 41+/- 8). V O2,max (ml kg(-1) min(-1)) was significantly increased (control, 21.8+/-2.2; training, 27.3+/-2.2; verapamil, 25.2+/-3.4; combined treatments, 26.9+/-2.3). Increasing ventricular preload with either exercise training or calcium channel blockade was coincident with faster tauVO2 and increased VO2,max.     

Hepatitis B surface antigen and hepatocellular carcinoma in Southern Africa

Summary Most series in Africa show a high percentage of hepatitis B surface Hepatitis antigen in hepatocellular carcinoma. Two groups of cases were investigated in this study. The one was derived from the autopsy material at Baragwanath hospital from subjects who had lived in Soweto, a large Black urban town. The second group consisted of male Black mineworkers generally originating from rural areas. A combination of the aldehydefuchsin stain and immunoperoxidase technique was used. The two groups showed totally different results. The Baragwanath series consisted of 24 hepatocellular carcinomas of which only 4 (17%) were HBsAg positive. Of the 24 cases, 14 had cirrhosis of which 9 were macronodular and 5 micronodular. Ten of these cases showed heavy iron overload. The series of male Black mineworkers comprised 22 cases of which 16 (72%) were HBsAg positive. Twelve of the 22 cases showed a macronodular cirrhosis and there were no micronodular cirrhoses. Only one case showed severe iron overload. These findings delineate two different populations of hepatocellular carcinoma in Southern Africa.     

Body position and cardiac dynamic and chronotropic responses to steady-state isocapnic hypoxaemia in humans

Neural mediation of the human cardiac response to isocapnic (IC) steady-state hypoxaemia was investigated using coarse-graining spectral analysis of heart rate variability (HRV). Six young adults were exposed in random order to a hypoxia or control protocol, in supine and sitting postures, while end-tidal PCO2 (PET,CO2) was clamped at resting eucapnic levels. An initial 11 min period of euoxia (PET,O2 100 mmHg; 13.3 kPa) was followed by a 22 min exposure to hypoxia (PET,O2 55 mmHg; 7.3 kPa), or continued euoxia (control). Harmonic and fractal powers of HRV were determined for the terminal 400 heart beats in each time period. Ventilation was stimulated (P < 0.05) and cardiac dynamics altered only by exposure to hypoxia. The cardiac interpulse interval was shortened (P < 0.001) similarly during hypoxia in both body positions. Vagally mediated high-frequency harmonic power (Ph) of HRV was decreased by hypoxia only in the supine position, while the fractal dimension, also linked to cardiac vagal control, was decreased in the sitting position (P < 0.05). However, low-frequency harmonic power (Pl) and the HRV indicator of sympathetic activity (Pl/Ph) were not altered by hypoxia in either position. These results suggest that, in humans, tachycardia induced by moderate IC hypoxaemia (arterial O2 saturation Sa,O2 85 %) was mediated by vagal withdrawal, irrespective of body position and resting autonomic balance, while associated changes in HRV were positionally dependent.     

The effect of tolbutamide on cerebral blood flow during hypoxia and hypercapnia in the anaesthetized rat

The increase in blood flow in the cerebral cortex of the anaesthetized rat during hypoxia and hypercapnia was investigated. Cerebral blood flow (CBF) was measured using the hydrogen clearance method with acutely implanted platinum electrodes. Hypoxia (PaO₂ 35.3±2.4 Torr) and hypercapnia (PaCO₂ 68.1±5.1 Torr) increased basal CBF from 76.3±9.0 ml/100g/min to 168.1±20.1 ml/100g/min and 162.4±31.9 ml/100g/min respectively. The sulphonylurea tolbutamide (1mM in 1%DMSO) had no significant effect on CBF in hyperoxia or in hypercapnia. However, it attenuated the increase of CBF during hypoxia by 66 ±11% (P<0.01). This suggests that opening of tolbutamide-sensitive potassium channels may be involved in the process of hypoxic vasodilation in the rat cerebral cortex.     

Lung surfactant-associated glycoproteins and proteolipids in human amniotic fluids evaluated by dot immunobinding assays

Dot immunobinding assays for the quantitation of two classes of proteins associated with lung surfactant phospholipids in human amniotic fluid are described. With the use of these assays it was determined that the two classes of surfactant proteins accumulate in the amniotic fluid at the same rate. The concentrations of disaturated phosphatidylcholine and the surfactant-associated proteins are less closely correlated. Centrifugation of amniotic fluids either before or after freezing resulted in a loss ranging from 10 to 35 percent of both surfactant disaturated phosphatidylcholine and proteins depending on the relative centrifugal force used. Preterm amniotic fluids contained significantly less of both surfactant-associated proteins, as well as disaturated phosphatidylcholine, than did term amniotic fluids which suggests that the use of these specific protein markers may enhance the assessment of fetal lung maturity.