Head injury, α-synuclein Rep1, and Parkinson's disease.

Objective: To test the hypothesis that variability in SNCA Rep1, a polymorphic dinucleotide microsatellite in the promoter region of the gene encoding α-synuclein, modifies the association between head injury and Parkinson's disease (PD) risk.

Methods: Participants in the Farming and Movement Evaluation (FAME) and the Study of Environmental Association and Risk of Parkinsonism using Case-Control Historical Interviews (SEARCH), 2 independent case-control studies, were genotyped for Rep1 and interviewed regarding head injuries with loss of consciousness or concussion prior to Parkinson's disease (PD) diagnosis. Logistic regression modeling adjusted for potential confounding variables and tested interaction between Rep1 genotype and head injury.

Occupation and risk of parkinsonism: a multicenter case-control study.

Background: We examined risk of parkinsonism in occupations (agriculture, education, health care, welding, and mining) and toxicant exposures (solvents and pesticides) putatively associated with parkinsonism.

Objective: To investigate occupations, specific job tasks, or exposures and risk of parkinsonism and clinical subtypes.

Design: Case-control.

A prospective study of sexual transmission of human T lymphotropic virus (HTLV)-I and HTLV-II.

Background: Cross-sectional studies support sexual transmission of human T lymphotropic virus (HTLV)-I/II; however, prospective incidence data, particularly for HTLV-II, are limited.

Methods: A cohort of 85 HTLV-positive (30 with HTLV-I and 55 with HTLV-II) blood donors and their stable (>or=6 months) heterosexual sex partners were followed biannually over the course of a 10-year period.

Results: Four of 85 initially seronegative sex partners of HTLV-I and -II carriers seroconverted, for an incidence rate (IR) of 0.

The epidemiology and disease outcomes of human T-lymphotropic virus type II.

Human T-lymphotropic virus type II (HTLV-II) is a human retrovirus which is endemic in Amerindian and pygmy tribes. Molecular subtypes show geographic segregation consistent with an ancient origin of this virus within humans in Africa or South America. More recently, injection drug users in the United States and Europe have become infected with HTLV-II, and secondary sexual transmission has introduced the virus at low levels into the general population and blood donors.