Melatonin, the Hormone of Darkness: From Sleep Promotion to Ebola Treatment

Melatonin is a hormone secreted by the enigmatic pineal gland in response to darkness, hence the name hormone of darkness. It has generated a great deal of interest as a therapeutic modality for various diseases particularly sleep disorders. This pleiotropic molecule has anti-inflammatory, antioxidant and anticoagulopathic properties in addition to its endothelial protective effects. In this article we discuss melatonin secretion and mechanisms of action as well as therapeutic rationale. We also highlight the potential utility of melatonin in the deadly modern-day Ebola epidemic.

Relationship between Visual Impairment, Insomnia, Anxiety/Depressive Symptoms among Russian Immigrants

BACKGROUND

Little is known about the association between visual impairment and insomnia symptoms in elderly populations. The purpose of this study was to ascertain associations between self-reported visual impairments and insomnia symptoms in a community-based sample of Russian immigrants.

METHOD

Sample consisted of 307 community-residing Russians (ages: 25-95 years, mean=72.64 ± 9.62; women=54% and men=46%). Semi-structured interviews assessed health-care needs and physical health characteristics. Collected demographic and health-related data were analyzed using SPSS 19.0.

RESULTS

Overall, 93% reported at least one of several major health problems: visual impairment (48.4%), hypertension (53%), diabetes (25.7%), arthritis (52.8%), cancer (10.5%), weight problems (34.1%), and anxiety/depressive symptoms (43%), 62% had an insomnia diagnosis. Unadjusted logistic regression analysis showed that individuals with visual impairment were nearly three times as likely as those without to report insomnia symptoms [OR = 2.73, p < 0.01; 95% CI = 1.68-4.48]. Adjusting for the presence of socio demographic variables reduced the odds to 2.68; further adjustment for social isolation and anxiety and depressed symptoms reduced the odds to 2.20.Anxiety/depression mediated the relationship between visual impairment and insomnia.

CONCLUSION

Individuals with visual impairment have twice the odds of reporting insomnia independent of anxiety/depression and social isolation, two common problems affecting quality of life in that population.

A Boophilus microplus vitellin-degrading cysteine endopeptidase

Here we describe the purification and characterization of a vitellin (VT) degrading cysteine endopeptidase (VTDCE) from eggs of the hard tick Boophilus microplus. A homogeneous enzyme preparation was obtained by chromatographic fractionation on ion-exchange and gel filtration columns and an autolysis step. This step consisted of incubation of a semipurified enzyme (after the first ion-exchange chromatography) at pH 4.0 that dissociated the enzyme from VT, to which VTDCE is naturally tightly associated. The enzyme purity was confirmed by capillary and native gel electrophoresis, and SDS-PAGE suggested the enzyme is a dimer of 17 and 22 kDa. VTDCE was active upon several synthetic substrates, with a preference for a hydrophobic or a basic residue in P1, and a hydrophobic residue in P2. VTDCE also hydrolysed haemoglobin, albumin, gelatin and vitellin. VTDCE is inactive in the absence of DTT and was totally inhibited by E-64, indicating it is a cysteine endopeptidase. Our results suggest that VTDCE is a major enzyme involved in yolk processing during B. microplus embryogenesis.

Murine Schistosoma bovis infection: analysis of parasitic and immune parameters

Humoral and cellular responses to Schistosoma bovis antigens have been evaluated over a period of 11 weeks in mice exposed to S. bovis cercariae and data analysed in the context of the parasitic parameters (worm and egg loads) recorded at days 30, 60 and 80 of the ongoing infection. Results revealed a decrease of worm burden, particularly marked for female worms, between day 60 and day 80 of infection suggesting a higher susceptibility of female schistosomes to attrition mechanisms. The B-cell response, studied by measuring the production of different isotypes, was directed against different stage specific antigens, with a predominance of IgG1 antibodies associated with a significant increase of IgA and IgE antibodies after egg deposition. The T-cell response, assessed after in vitro stimulation of splenocytes, showed a predominant production of Th-2 cytokines (IL-4, IL-5 and IL-10) occurring after egg laying. Interestingly in contrast to S. mansoni infection the Th-2 polarization did not seem to be exclusively triggered by egg-associated antigens since significant amounts of IL-10 were produced after stimulation with adult worm antigen preparation (SWAP) before the beginning of egg deposition.