Sharon Moalem

Aluminum and Alzheimer's disease, a personal perspective after 25 years

It is now 25 years since the publication of our original paper investigating the association aluminum with Alzheimers disease. This publication reported on the results of scanning electron microscopy coupled x-ray spectrometry microprobe elemental studies of both neurofibrillary tangle-bearing and tangle-free neurons in the hippocampus of cases of Alzheimers disease and controls. Peaks related to the presence of aluminum were consistently detected within the tangle-bearing neurons. This paper supported the association of aluminum and Alzheimers disease on the cellular level of resolution and caused considerable interest and discussion. Subsequent work demonstrated prominent evidence of aluminum accumulation in the tangle-bearing neurons of cases of amyotrophic lateral sclerosis/parkinsonism-dementia complex of Guam. This latter observation has now been replicated using five different forms of microanalysis. Finally, using laser microprobe mass analysis, we demonstrated that the abnormally high aluminum-related signal which we originally detected was actually located within the neurofibrillary tangle, itself, and was accompanied by excess concentrations of iron. Although it is unlikely that aluminum represents an etiologic cause of Alzheimers disease, we believe that this highly reactive element, known to cross-link hyperphosphorylated proteins, may play an active role in the pathogenesis of critical neuropathologic lesion in Alzheimers disease and other related disorders.

Does female ejaculation serve an antimicrobial purpose

Women have glandular tissue below the bladder and surrounding the urethra that appears to be homologous to the male prostate. This tissue (also called female prostate or Skenes glands) appears to the source of a viscous, white secretion, which exits from the urethra upon sexual stimulation in some women. Analysis of this secretion (also known as female ejaculate), and comparison with pre-coital urine from the same women, revealed that its composition was unlike urine and often contained components also found in male seminal fluid (minus the sperm). The female ejaculate had lower levels of creatinine, but had elevated levels of prostate specific antigen, prostatic acidic phosphatase, prostate specific acid phosphatase, and glucose. The functional importance of female ejaculate has yet to be fully elucidated. It is possible that retention of a prostatic tissue homolog and its glandular secretion in women is merely a vestige of development and differentiation from an embryonic, gender-neutral body plan. We hypothesize that female ejaculation has a unique function in producing a secretion into the urethra that provides protection from urinary tract infections (UTIs). We further predict that female ejaculate contains antimicrobial compounds including elements such as zinc. We also hypothesize that retention of prostatic tissue and an ability to ejaculate its glandular secretion were maintained in women because these traits provided an evolutionary advantage. Specifically: (1) women who could ejaculate antimicrobial secretions into the urethra were less likely to suffer UTIs (particularly coitus-induced UTIs), (2) women without UTIs were more likely to be receptive to coitus at a greater frequency, (3) women engaging in frequent coitus were more likely to become pregnant, and (4) women who became pregnant often were more likely to successfully reproduce the species.