Drug use, sexual activity, and suicidal behavior in U.S. high school students.

Data from the 1990 Youth Risk Behavior Survey were used to examine the interrelationship of drug use, sexual activity, and suicidal behavior in U.S. high school students. Findings indicated adolescents who engaged in substance use and/or sexual activity were more likely to experience suicide ideation and behavior than those who abstained from such activities. Data analysis revealed a significant and positive relationship between cocaine use and severity of outcomes of suicide attempts. Marijuana use and alcohol use were related to suicide behavior, but these relationships were not as strong as those noted for cocaine use. The study also revealed a positive relationship between frequency of sexual activity and attempted suicide, but could not determine whether such sexual activity was coerced, forced, or voluntary in nature.

Transient membrane association of the precursors of cathepsin C during their transfer into lysosomes.

Transport of the lysosomal enzyme cathepsin C was studied in Morris hepatoma 7777 cells. Subcellular fractions obtained after isopyenic centrifugation in sucrose gradients of labelled cell homogenates were sequentially extracted by hypo-osmotic shock, Na2CO3 and Triton X-100. Polypeptides related to cathepsin C were immunoprecipitated and analysed by SDS/PAGE and fluorography. At early times after synthesis and for up to 60 min, precursor polypeptides of cathepsin C are distributed in endoplasmic reticulum and Golgi fractions, in membrane-associated form, as Triton X-100 is necessary for their extraction. At 2 h and later after synthesis, intermediate and mature forms of the enzyme can be totally extracted by hypo-osmotic shock from gradient fractions corresponding to the lysosomes of Morris hepatoma 7777 cells.