Looking forward to a general theory on population aging

The main theories on population aging based on recent data on human longevity, life expectancy, morbidity changes, disability trends, and mortality decrease are presented and discussed within their own geographic, cultural, socioeconomic, and medical contexts. The complex interactions between all these components do not facilitate trend forecasting of aging population (healthy aging versus disability pandemic). In the context of population aging, four elements were introduced with their implications: 1) an increase in the survival rates of sick persons, which would explain the expansion of morbidity, 2) a control of the progression of chronic diseases, which would explain a subtle equilibrium between the decrease in mortality and the increase in disability, 3) an improvement of the health status and health behaviors of new cohorts of elderly people, which would explain the compression of morbidity, and eventually 4) an emergence of very old and frail populations, which would explain a new expansion of morbidity. Obviously, all these elements coexist today, and future trend scenarios-expansion or compression of disability-depend on their respective weights leading to the need of elaborating "a general theory on population aging." This theory has to be based on a world harmonization of functional decline measurements and a periodic "International Aging Survey" to monitor global aging through a sample of carefully selected countries.     

Calculation of crystalline lens power using a modification of the Bennett method

We present a method for measuring lens power from extended depth OCT biometry, corneal topography, and refraction using an improvement on the Bennett method. A reduced eye model was used to derive a formula for lens power in terms of ocular distances, corneal power, and objective spherical equivalent refraction. An error analysis shows that the formula predicts relaxed lens power with a theoretical accuracy of ± 0.5 D for refractive error ranging from −10 D to + 10 D. The formula was used to calculate lens power in 16 eyes of 8 human subjects. Mean lens power was 24.3 D ± 1.7 D.OCIS codes: (170.4500) Optical coherence tomography, (170.4580) Optical diagnostics for medicine, (330.7325) Visual optics, metrology, (330.7326) Visual optics, modeling     

Herpes simplex virus and HIV-1: deciphering viral synergy

Recent proof-of-concept randomised controlled trials have shown a causal relation between herpes simplex virus (HSV) type 2 infection and HIV-1 replication in co-infected individuals. We explore the mechanisms that may operate to enhance reciprocal viral replication. Direct interactions could involve HIV-1-related immune deficiency, disruption of mucosal barrier by HSV infection/reactivation, HSV-induced mucosal cell recruitment, transactivation of HIV-1 replication by HSV proteins, and immune modulation by HSV decoys. Indirect interactions might coexist through disturbances of the vaginal flora during HSV shedding and systemic immune activation. In co-infected individuals, suppressive HSV treatment reduces HIV-1 genital and systemic excretion. This finding is a likely result of efficacious prevention of HSV2 reactivations, and perhaps of other herpesviruses. Strategies to control HSV2 and other herpesviruses deserve urgent attention and should become part of the HIV-1 prevention and care package.     

Rituximab decreases the risk of lymphoma in patients with HIV-associated multicentric Castleman disease

HIV-associated multicentric Castleman disease (MCD) is associated with a high risk of developing non-Hodgkin lymphoma (NHL). Rituximab is effective in HIV-MCD, but its impact on NHL incidence remains unknown. From a single-center prospective cohort, 113 patients were identified with a diagnosis of HIV-MCD for the present study. To compare the incidence of NHL between patients who had received a rituximab-based treatment (R+ group) and those who had not (R- group), data were analyzed before and after matching on propensity scores and after multiple imputation. The mean follow-up was 4.2 years. In the R- group (n = 65), 17 patients developed NHL (incidence, 69.6 of 1000 person years). In the R+ group (n = 48), only 1 patient developed NHL (incidence, 4.2 of 1000 person years). Based on the propensity score-matching method, a significant decrease in the incidence of NHL was observed in patients who had been treated with rituximab (hazard ratio, 0.09; 95% confidence interval, 0.01-0.70). Ten Kaposi sarcoma (KS) exacerbations and 1 newly diagnosed KS were observed in 9 patients after rituximab therapy. Rituximab was associated with an 11-fold lower risk of developing lymphoma. KS exacerbation was the most challenging adverse event after rituximab therapy.