Search

People in community corrections have rates of HIV and sexual risk behaviors that are much higher than the general population. Prior literature suggests that criminal justice involvement is associated with increased sexual risk behaviors, yet these studies focus on incarceration and use one-sided study designs that only collect data from one partner. To address gaps in the literature, this study used the Actor Partner-Interdependence Model with Structural Equation Modeling (SEM), to perform a dyadic analysis estimating individual (actor-only) partner-only, and dyadic patterns (actor-partner) of criminal justice involvement and greater sexual risks in a sample of 227 men on probation and their intimate partners in New York City, United States. Standard errors were bootstrapped with 10,000 replications to reduce bias in the significance tests. Goodness of fit indices suggested adequate or better model fit for all the models. Significant actor-only relationships included associations between exposures to arrest, misdemeanor convictions, time spent in jail or prison, felony convictions, lifetime number of incarceration events, prior conviction for disorderly conduct and increased sexual risk behaviors. Partner only effects included significant associations between male partners conviction for a violent crime and their female partners’ sexual risk behaviors. Men’s encounters with police and number of prior misdemeanors were associated with their own and intimate partners’ sexual risk behaviors. Women’s prior arrest was associated with their own and intimate partners’ sexual risk behaviors. The results from the present study suggest that men on probation and their intimate partners’ criminal justice involvement are associated with increased engagement in sexual risk behaviors. It is necessary to conduct greater research into developing dyadic sexual risk reduction and HIV/STI prevention interventions for people who are involved in the criminal justice system.

Cell-cycle transitions in higher eukaryotes are regulated by different cyclin-dependent kinases (CDKs) and their activating cyclin subunits. Based on pioneering findings that a dominant-negative mutation of CDK1 blocks the cell cycle at G2-M phase, whereas dominant-negative CDK2 inhibits the transition into S phase, a model of cell-cycle control has emerged in which each transition is regulated by a specific subset of CDKs and cyclins. Recent work with gene-targeted mice has led to a revision of this model. We discuss cell-cycle control in light of overlapping and essential functions of the different CDKs and cyclins.

ALTHOUGH mitotic cyclins are well-known substrates for ubiquitin-mediated proteolysis at the metaphase–anaphase transition1–4, their degradation is not essential for separation of sister chromatids5–8; several lines of evidence suggest that proteolysis of other protein(s) is required, however4,6,9–11. Here we report the anaphase-specific proteolysis of the Schizosaccharomyces pombe Cut2 protein, which is essential for sister-chromatid separation12,13. Cut2 is located in the nucleus, where it is concentrated along the short metaphase spindle. The rapid degradation of Cut2 at anaphase requires its amino-terminal region and the activity of Cut9 (ref. 14), a component of the 20S cyclosome/ anaphase-promoting complex (APC), which is necessary for cyclin destruction3,4,11. Expression of non-degradable Cut2 blocks sister-chromatid separation but not cell-cycle progression. This defect can be overcome by grafting the N terminus of cyclin B onto the truncated Cut2, demonstrating that the regulated proteolysis of Cut2 is essential for sister-chromatid separation.

To the Editor, Cyclin-dependent kinases (CDKs) are protein kinases involved in critical cellular processes, such as cell cycle or transcription, whose activity requires association with specific cyclin subunits. Based on sequence similarity, the human genome contains 21 genes encoding CDKs and five additional genes encoding a more distant group of proteins known as CDK-like (CDKL) kinases. The current nomenclature for CDK proteins includes 11 classical CDKs (CDK1–11), two newly proposed family members (CDK12 and 13) and additional proteins whose names are based on the presence of a cyclin-binding element (PFTAIRE and PCTAIRE proteins) or simply based on a sequence relationship with the original CDKs, such as CDC2-like kinases (CDC2L) or cell cycle-related kinases (CCRK)

In vertebrates, mature eggs are arrested at the second meiotic metaphase by the cytostatic factor (CSF), now known to be the c-mos proto-oncogene product (Mos). Fertilization or egg activation triggers a transient increase in the cytoplasmic free calcium and releases the meiotic arrest by inactivating maturation/mitosis-promoting factor (MPF). CSF or Mos, which is also inactivated by the calcium transient, seems to stabilize MPF in mature eggs and CSF-injected embryos. Thus, it was assumed that CSF inactivation is the primary cause of MPF inactivation on meiotic release. We have directly compared the degradation kinetics of CSF (Mos) and MPF during meiotic release, using the same batch of Xenopus eggs. We report here that, at the molecular level, cyclin subunits of MPF are degraded before Mos is degraded and, at the physiological level, that MPF activity is inactivated before CSF activity during activation of Xenopus eggs. These results, in conjunction with circumstantial evidence, support the novel view that a calcium transient on fertilization induces a CSF-independent pathway for MPF inactivation, whereas CSF inactivation during meiotic release serves only to allow the fertilized egg to enter mitosis.

INFECTION of HeLa cells with poliovirus causes an inhibition of host cell protein synthesis with a concomitant conversion of polysomes to single ribosomes1, 2. This process is thought to be mediated by a product of the viral genome, for infection of cells with virus particles which have been inactivated by ultraviolet irradiation does not affect the rate of protein synthesis1. The inhibition acts directly on translation rather than on the production of mRNA1, 3, yet neither chain elongation nor the release of polypeptide chains from ribosomes seems to be affected2. Chain initiation, therefore, is the only possible target. Willems and Penman have suggested that cellular mRNA is inactivated after infection, preventing its reassociation with ribosomes3. To test these hypotheses, we assayed for the presence of inhibitors of initiation in poliovirus-infected HeLa cell cytoplasm, using a lysate of rabbit reticulocytes that initiates the synthesis of new polypeptide chains at a rate comparable with that in intact cells.

PROTEIN synthesis in intact reticulocytes is severely restricted when iron is lacking in the incubation medium and can be restored by the addition of haemin1,2. In the lysate derived from such cells, protein is synthesized at a rate similar to that in intact cells3, but finishes abruptly after a few minutes unless haemin is added4,5. Haemin seems to act by stabilizing the capacity of the lysate to initiate protein synthesis, because in the absence of added haemin, polysomes disappear and their associated nascent chains are released4. It is not clear which step in initiation fails under these conditions. There is good evidence that native subunits and methionyl t-RNAF are directly involved in the process of initiation6–9. We examined the formation of complexes between the native subunits present in the lysate and met-tRNAF when lysates were synthesizing protein in the presence and absence of added haemin.

Oogenesis. Developmental Biology: A Comprehensive Synthesis, Vol. 1. Edited by Leon W. Browder. Plenum: 1985. Pp.632. $75, £71.25.