Apolipoprotein E—associated risk for Alzheimer's disease in the African-American population is genotype dependent

As a part of our ongoing study on Alzheimer's disease (AD) in elderly African Americans, we obtained clinical assessment and apolipoprotein E (ApoE) genotype data on 288 individuals (including 60 with AD). The ApoE σ4 allele frequency was significantly increased in AD patients compared with controls. The age-adjusted odds ratio (OR) for AD in σ4 homozygotes was 4.83 (95% confidence interval [CI], 1.71–13.64) compared with the σ3/σ3 genotype, but the OR for AD with the σ3/σ4 genotype did not reach significance (1.20; 95% CI, 0.58–2.45). These findings suggest that the association between ApoE σ4 and AD is weaker in African Americans than in whites.     

Biosocial factors affecting menarche in a mixed Nigerian population.

A prospective study of school girls in a mixed Nigerian population revealed that the mean menarcheal age was 13.98 +/- 1.30 years. The mean menarcheal age was influenced by the social class of the parents, being higher in the lower social class, there were considerable variations in the biologic measurements (height, weight and body mass index) among girls who attained menarche.     

Mutation of luxS of Streptococcus pneumoniae affects virulence in a mouse model

The LuxS protein is required for the biosynthesis of the type 2 autoinducer (AI-2), which is involved in quorum sensing in a wide range of bacterial species. We have determined the effects of a defined luxS mutation on the virulence of Streptococcus pneumoniae. Although the luxS mutant displayed reduced virulence relative to its wild-type parent, the type 2 strain D39, it was by no means avirulent in a mouse model. After intranasal administration, the luxS mutant was able to colonize the nasopharynx of the mouse as efficiently as the wild type. However, it was less able to spread from the nasopharynx to the lungs or the blood. Intraperitoneal coadministration studies indicated that the luxS mutant was less fit and was readily outcompeted by wild-type D39. However, when administered on its own by this route, the mutant was able to proliferate and cause fatal systemic disease, albeit at a lower rate than the wild type. Western blot analysis of whole-cell lysates of the mutant and its parent did not reveal any differences in the levels of several well-characterized virulence proteins. However, analysis of Coomassie blue-stained protein profiles after separation by sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that mutation of luxS had pleiotropic effects on protein expression in all cellular compartments. This is consistent with the product of luxS having a regulatory role in S. pneumoniae. This is the first report of a direct role for luxS (and by inference, AI-2) in the virulence of a gram-positive pathogen. However, the fact that mutagenesis of luxS does not completely attenuate S. pneumoniae has implications for the possible use of AI-2 antagonists for treatment of pneumococcal infections.     

Sociodemographic factors in mental disorders associated with infertility in Nigeria

The mental status of 37 female patients with infertility and that of 37 healthy controls was evaluated using General Health Questionnaire, Present State Examination, and clinical assessment. An interview schedule, designed to elicit information on sociodemographic, psychiatric predisposing, and obstetric factors, was also administered. A significantly higher proportion (29.7%) of the patients was found to have diagnosable psychopathology, mainly depressive episode and generalized anxiety disorder. Compared with the control group, the infertile women experienced poorer marital relationships, had a significant family history of infertility, were more negatively predisposed to child adoption. and had a greater history of surgery and induced abortion. Polygamy was found to have a close association with psychopathology in the sample of infertile women. The implications of these findings and ways of improving the mental status of the infertile woman are discussed.     

Tissue Injury-Inducing Potential of Unmodified ECT: Serial Measurement of Acute Phase Reactants

Eight subjects with acute functional psychoses receiving unmodified electroconvulsive therapy (ECT) at Ibadan were investigated for occult or subclinical internal tissue damage by serial measurements of eight acute phase reactants. Samples of venous blood were collected from each patient at pretreatment, two within treatment, and one at posttreatment. The acute phase proteins assayed were C-reactive protein (CRP), alpha-2-macroglobulin, ceruloplasmin, factor B, C-4 protein, C-3 protein, transferin, and alpha-1-antitrypsin. Except for CRP, the values of the proteins did not change during treatment. CRP values decreased posttreatment and were not detectable in the last sample in five subjects in whom values had been present pretreatment. Our data do not support fears of occult internal tissue damage during unmodified ECT. The consistent decrease in CRP levels posttreatment when patients no longer exhibited psychotic symptoms could not be explained by type of psychosis, intramuscular injections, or changes in drugs and diet; its significance is not known.