The in vitro fertilisation programme at Tygerberg Hospital and the University of Stellenbosch. Five years' experience, April 1983-January 1988

The results of the in vitro fertilisation programme at Tygerberg Hospital for the period April 1983 to January 1988 are presented. Of the 1117 laparoscopies performed, 825 patients reached the transfer stage. A live-birth rate of 9.3% was achieved. The pregnancy rate after transfer of 4 embryos was 25.9% compared with 15.4% after 2 embryos and 10.8% after 3 embryos (P = less than 0.0001). The multiple pregnancy rate was 2.8% in the group receiving 2 embryos and 11.7% and 10.4% in those receiving 3 and 4 embryos, respectively. Of the 77 successful pregnancies (90 babies), 1 baby died at 34 weeks' gestation as the result of abruptio placentae due to preeclampsia and 1 cot death occurred. The only congenital abnormality encountered was a cleft palate.     

The effect of prostaglandin E1 on acute pulmonary artery hypertension during oleic acid-induced respiratory dysfunction

This study examined the general effect of intravenous PGE1 on RV Ees and effective PA elastance (EA) during acute pulmonary hypertension associated with oleic acid infusion. In eight pigs, RV end-systolic elastance was quantified with the Ees and Ea was defined with reference to the Windkessel model. Oleic acid infusion increased mean PAP and Ea. Prostaglandin E1 reduced PAP and decreased Ea. Ees did not change throughout the study. Mean arterial pressure was reduced and the pulmonary shunt was increased after PGE1 infusion. The PaO2 was reduced. Data from this study suggest that although PGE1 is effective in reducing PAP, it is not as effective in reducing RV afterload. Furthermore, PGE1 does have significant side effects such as reduction of systemic arterial pressure and an increase in pulmonary shunt.     

The effect of inhibition of mitochondrial energy metabolism on the transient inward current of isolated guinea-pig ventricular myocytes

Delayed afterdepolarizations (DADs) might underlie ischemic or reperfusion arrhythmias (Ferrier et al., 1985; Coetzee and Opie, 1987). These DADs are the result of a transient inward current iti, which is caused by instability of the intracellular level of free Ca2+ (Cai) due to an oscillatory release of Ca from the sarcoplasmic reticulum (Kass et al., 1978). DADs are known to be abolished by hypoxia and by metabolic inhibition (Di Gennaro et al., 1987; Coetzee and Opie, 1987), which could be caused by a number of different mechanisms: (1) The large increase of potassium conductance associated with metabolic inhibition (Vleugels et al., 1980; Isenberg et al., 1983) could prevent iti from causing a marked depolarization, and would thus "mask" the DADS. (2) Although metabolic inhibition will eventually result in an increase of Cai, a temporary decrease could initially take place, thereby minimizing the Ca instability. Two mechanisms are known which might produce such an effect: Firstly, the shortening of the action potential which occurs during metabolic inhibition will markedly reduce the time during which Ca channels remain open, thereby causing a diminished total Ca influx during the action potential (Isenberg et al., 1983; Noma and Shibasaki, 1985; Kakei et al., 1985). Secondly, a direct reduction of iCa by a decrease in ATP concentration, described by Irisawa and Kokubun (1983), could also contribute to a decreased Ca load. (3) Metabolic inhibitors could possibly interfere with the cycling of Ca between different compartments within the cell, thereby altering the temporal variation in Cai, and thus influencing iti.(ABSTRACT TRUNCATED AT 250 WORDS)     

Differences in extent of genetic introgression between sympatric Culex pipiens and Culex quinquefasciatus (Diptera: Culicidae) in California and South Africa

Comparisons of five morphological characters, 12 enzyme electrophoresis profiles, and Wolbachia pipientis infection rates were used to characterize populations of members of the Culex pipiens L. complex in California and South Africa. In South Africa, male phallosome DV/D ratio, male maxillary palp index, branching of siphonal seta 1a, the enzyme locus Mdhp-1, and W. pipientis infection rates proved highly diagnostic for separating Culex quinquefasciatus from Cx. pipiens phenotypes. In Johannesburg, where sympatric members of the Cx. pipiens complex were analyzed as one population, a significant Wahlund Effect was observed in the enzyme loci such as Ao, 6-Pgdh, Mdh-2, and Pgm. In California, all populations of the Cx. pipiens complex were in Hardy Weinberg equilibrium at all polymorphic enzyme loci examined. Additionally, in California, all populations had similar W. pipientis infection rates and appeared morphologically identical (except for DV/D ratio, in extreme north and south). These findings indicate that in South Africa, Cx. pipiens and Cx. quinquefasciatus remain as genetically distinct populations and behave as separate species. Conversely, in California, there is considerable genetic introgression between Cx. pipiens and Cx. quinquefasciatus, and they behave as a single species.     

Predictive value of normal sperm morphology: a structured literature review

The aim of the study was to conduct a structured review of theliterature published on the use of normal sperm morphology,as an indicator of male fertility potential in the in-vitrofertilization (IVF) situation, and to establish the universalpredictive value of this semen parameter. Published literaturein which normal sperm morphology was used to predict fertilizationand pregnancy, during the period 1978-1996, was reviewed. Atotal of 216 articles were identified by the sourcing methodology,but only 49 provided data that could be tabulated and analysed.Of these, only 18 provided sufficient data for statistical analysis.Fifteen studies used the strict criteria to evaluate sperm morphology,two used World Health Organization (WHO) guidelines and oneused both the strict criteria and the WHO guidelines. All thestudies (n=10) using the 5 and 14% normal sperm morphology thresholds(strict criteria) produced positive predictive values for IVFsuccess. In the prediction of pregnancy, 82% (9/11) and 75%(6/8) of the studies produced positive predictive values whenusing the 5% and 14% thresholds respectively. Aggregating thedata produced around the 5% normal sperm morphology threshold(strict criteria), the overall fertilization rates were 59.3%(1979/3337; per oocyte) for the 4% group and 77.6% (10345/13327;per oocyte) for the >4% group, and the overall pregnancyrates were 15.2% (60/395; per cycle) and 26.0% (355/1368; percycle) respectively. The no-transfer rates across the 5% thresholdwere 24.0% (86/359; per cycle) in the 4% group compared to 7.4%(80/1088; per cycle) in the >4% group. The inclusion of anaccurately evaluated normal sperm morphology count as an integralpart of the standard semen analysis makes this analysis stillthe most cost-effective means of evaluating the male factor.     

Sequence variation and size ranges of CAG repeats in the Machado-Joseph disease, spinocerebellar ataxia type 1 and androgen receptor genes

A subgroup of trinucleotide repeat diseases result from abnormalexpansions of CAG repeats which are translated into polyglutaminestretches. As yet there is little understanding of how the polyglutaminesfunction either normally, or when expanded. We have investigatedthese sequences in the Machado-Joseph disease, androgen receptorand spinocerebellar ataxia type 1 genes in humans and otherprimates. None of the 748 normal chromosomes that were examinedhad more than 34 uninterrupted gluta-mine codons in the Machado-Josephdisease gene. Similarly, no normal alleles with more than 39uninterrupted glutamine codons have been reported for the otherdisease genes associated with polyglutamine expansions. Sequenceanalyses of the repeats in primates revealed shorter polyglutaminestretches in some of the non-human primates at all three lociand marked diversions from the expected polyglutamines in theorang-utan Machado-Joseph gene and in the marmoset spinocerebellarataxia type 1 gene. These data suggest that conservation ofthese polyglutamine stretches may not always be necessary fornormal gene function.     

Anemia in surgical intensive care patients

BACKGROUND: The cause of the anemia of patients in surgical intensive care units (SICU) is not completely clear but is likely to be multifactorial. This study investigated a possible role for immune activation in the anemia of SICU patients. METHODS: Neopterin plasma levels, as a measure of T-cell-macrophage-axis activation, RBC-counts, Hb, Hct, MCV, MCH, MCHC, RDW, HDW, red cell morphology and iron status were determined in a group of 47 SICU patients. RESULTS: The study confirms the presence of a moderate anemia (Hb = 10.38 +/- 13 g/dL) in SICU patients. Abnormal red blood cell morphology was observed in 82% of all patients over at least part of their ICU-stay. Markedly enhanced T-cell-macrophage-axis activity was evidenced by a significant increase in the plasma neopterin levels of the patient group (44 +/- 79.6 nmol/L) compared to that of the control group (3.38 +/- 4.9 nmol/L). Iron metabolism was found to be disturbed. CONCLUSIONS: The red cell distribution width, the morphological results, the enhanced macrophage activation state, as well as the results of the iron status, point towards a contribution of an immune-associated functional iron deficiency to the anemia of SICU patients.