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.     

Cylindrical spirals of myofilamentous origin associated with exertional cramps and rhabdomyolysis

We describe the presence of cylindrical spirals on muscle biopsy from a 31-year-old man who developed rhabodomyolysis following a long run. He had a prior history of exertional cramps and myoglobinuria. His maternal grandfather had similar symptoms. Transmission electron micrographs demonstrated continuity between the lamellae of the cylindrical spirals and native myofilaments. Whether these unusual structures confer a derangement in myofilament function is uncertain.     

A path-analytical approach to differentiate between direct and indirect drug effects on negative symptoms in schizophrenic patients

The hypothesis that differences in drug effects of risperidone and haloperidol on negative symptoms in schizophrenia are secondary to effects on positive, extrapyramidal, and depressive symptoms was investigated by means of an analysis of the data from the USA-Canada risperidone double-blind randomized clinical trial of 523 chronic schizophrenic patients. Regression analyses in the total sample and within treatment groups confirmed a strong relationship between changes in negative symptoms and the other variables studied (R²=0.50–0.51,p<0.001). Only depressive symptoms did not contribute significantly to these results (p>0.10). Path analysis showed that the greater mean change (p<0.05) of negative symptoms with risperidone compared to haloperidol could not be fully explained by correlations with favourable effects on positive and extrapyramidal symptoms. The relationship between shift in extrapyramidal symptoms and shift in negative symptoms failed to reach statistical significance; however, there was a clear tendency in the expected direction in both treatment groups.     

Radiotherapy in the treatment of low-grade astrocytomas

Between 1954 and 1986 inclusive, 160 children in the North West Region of England were registered with histologically proven lowgrade astrocytomas (grade 1 or 2). Ten died before receiving any treatment, and a further seven died within 28 days of surgery, leaving 143 children whose survival in relation to treatment modality is the subject of this paper. Low-grade astrocytomas are responsive to radiation therapy. This treatment has no clear benefit to offer children with superficial tumours that can be resected completely or nearly so, but significantly improves survival rates when tumours are deep-seated and not amenable to excision.