The LAR-family protein tyrosine phosphatase sigma (PTPsigma, encoded by the gene Ptprs) consists of a cell adhesion-like extracellular domain composed of immunoglobulin and fibronectin type-III repeats, a single transmembrane domain and two intracellular catalytic domains. It was previously shown to be expressed in neuronal and lung epithelial tissues in a developmentally regulated manner. To study the role of PTPsigma in mouse development, we inactivated Ptprs by gene targeting. All Ptprs+/- mice developed normally, whereas 60% of Ptprs-/- mice died within 48 hours after birth. The surviving Ptprs-/- mice demonstrated stunted growth, developmental delays and severe neurological defects including spastic movements, tremor, ataxic gait, abnormal limb flexion and defective proprioception. Histopathology of brain sections revealed reduction and hypocellularity of the posterior pituitary of Ptprs-/- mice, as well as a reduction of approximately 50-75% in the number of choline acetyl transferase-positive cells in the forebrain. Moreover, peripheral nerve electrophysiological analysis revealed slower conduction velocity in Ptprs-/- mice relative to wild-type or heterozygous animals, associated with an increased proportion of slowly conducting, small-diameter myelinated fibres and relative hypomyelination. By approximately three weeks of age, most remaining Ptprs-/- mice died from a wasting syndrome with atrophic intestinal villi. These results suggest that PTPsigma has a role in neuronal and epithelial development in mice.

Although male condoms are the best form of protection against HIV/STDs, they are not the most effective method for preventing unintended pregnancy. Consequently, use of condoms and a highly effective contraceptive-referred to as dual use-is recommended as the optimal protection against both disease and pregnancy. However, little is known about the factors that promote dual use. This study examined associations of dual method use with women's background characteristics, intrapersonal factors, and relationship characteristics. Data are from a random sample of women selected from a large managed care organization in the Pacific Northwest. The analytic sample contained 371 women who completed a telephone survey and reported use of contraceptives in the past 3 months. Three mutually exclusive method use groups were constructed: effective contraceptive only (hormonal methods, intrauterine device, surgical sterilization) (59%), condom only (24%), and dual use (18%). Variables hypothesized to influence dual use were compared across the three groups in bivariate and multivariate analyses. Findings indicate that women who were younger, reported more than one sexual partner in the past year, and were highly motivated to avoid HIV/STDs--were more likely to use dual methods rather than condoms only or an effective contraceptive method. Women confident about using condoms without feeling embarrassed or breaking the sexual mood were more likely to use dual methods rather than a single effective method. Finally, women with confidence in their ability to use condoms correctly are more likely to rely solely on condoms. Policy and practice implications are discussed.

Unintended pregnancy disproportionately affects Latina women. One factor contributing to unintended pregnancy among Latinas is the low rate of contraceptive use. This study examined correlates of effective contraceptive use among a sample of Latina women (n=202) at increased risk for HIV. In addition to traditional intrapersonal variables (i.e., perceived risk of pregnancy, motivation to avoid pregnancy), the present study examined the role of the male partner and relationship factors (i.e., relationship commitment, duration, pregnancy prevention decision-making) on contraceptive use. Participants were recruited from clinics and community locations in East Los Angeles and administered a 60-minute in-person interview. Multivariate logistic regression was used to compare women who consistently used effective contraceptives (36%) to women using no method or an ineffective method. Women in relationships of 1 to 2 years were nearly 3 times more likely to use an effective contraceptive compared to women in relationships of less than 1 year (odds ratio (OR)=2.7, 95% CI 1.1, 6.7). Women were more than twice as likely to use an effective method if they reported a high level of involvement in decision-making about whether to use contraception (OR=2.3, 95% CI 1.1, 4.7) or had discussed contraception with their partner (OR=2.4, 95% CI 1.03, 5.6). This study provides additional information about the importance of male partners and relationship factors in contraceptive use among Latina women. Efforts to prevent unintended pregnancy need to address the role of relationship factors in the sexual risk and protective behaviors of Latinas.