Risk and protective factors among youth offenders.

This exploratory study examined the risk and protective factors of youth offenders and their relation to recidivism. The sample consisted of 76 male and female juvenile probationers within a large metropolitan area. Archival records on probationers provided data on prior offenses, personal characteristics, familial conditions, drug use, peer selection, school performance, role models, and activities and hobbies. It was found that protective factors, specifically personal characteristics, familial conditions, and peer selection, differentiated nonrepeat offenders and repeat offenders. The present body of findings supports the adaptive model of resiliency and reinforces the importance of enhancing protective factors in youth offenders as a means of deterring delinquent behavior.

The crystal structure of urease from Klebsiella aerogenes.

The crystal structure of urease from Klebsiella aerogenes has been determined at 2.2 A resolution and refined to an R factor of 18.2 percent. The enzyme contains four structural domains: three with novel folds playing structural roles, and an (alpha beta)8 barrel domain, which contains the bi-nickel center. The two active site nickels are 3.5 A apart. One nickel ion is coordinated by three ligands (with low occupancy of a fourth ligand) and the second is coordinated by five ligands. A carbamylated lysine provides an oxygen ligand to each nickel, explaining why carbon dioxide is required for the activation of urease apoenzyme. The structure is compatible with a catalytic mechanism whereby urea ligates Ni-1 to complete its tetrahedral coordination and a hydroxide ligand of Ni-2 attacks the carbonyl carbon. A surprisingly high structural similarity between the urease catalytic domain and that of the zinc-dependent adenosine deaminase reveals a remarkable example of active site divergence.

In vitro activation of urease apoprotein and role of UreD as a chaperone required for nickel metallocenter assembly.

The formation of active urease in Klebsiella aerogenes requires the presence of three structural genes for the apoprotein (ureA, ureB, and ureC), as well as four accessory genes (ureD, ureE, ureF, and ureG) that are involved in functional assembly of the metallocenter in this nickel-containing enzyme. Slow and partial activation of urease apoprotein was observed after addition of nickel ion to extracts of Escherichia coli cells bearing a plasmid containing the K. aerogenes urease gene cluster or derivatives of this plasmid with deletions in ureE, ureF, or ureG. In contrast, extracts of cells containing a ureD deletion derivative failed to generate active urease, thus highlighting a key role for UreD in the metallocenter assembly process. Site-directed mutagenesis methods were used to overexpress ureD in the presence of the other urease genes, and the UreD protein was found to copurify with urease. A molecule of native urease apoprotein is capable of binding 0, 1, 2, or 3 molecules of UreD, consistent with a trimeric structure of urease catalytic units. The UreD-urease apoprotein complexes are competent for activation by nickel, with the level of activity obtained being directly related to the number of UreD molecules bound per urease molecule. Activation of the UreD-urease complexes is rapid and accompanied by UreD dissociation. We propose that UreD is a chaperone protein which stabilizes a urease apoprotein conformation that is competent for nickel incorporation.

Coming together for change: workshops for women in the nursing home.

A series of therapeutic and educational workshops were conducted with women nursing home residents with the twin goals of improving self-esteem and self-reliance, and facilitating community building and networking. Alongside these workshops were nursing home staff trainings whereby staff were encouraged to articulate their needs and those of resident women in productive ways.

Advanced ovarian carcinoma diagnosed during pregnancy in a patient with human immunodeficiency virus infection.

Many malignancies appear to occur with increased frequency and aggressive patterns of spread in patients seropositive for human immunodeficiency virus (HIV). The relationship between HIV infection and cervical neoplasia suggests that these patients present with more advanced disease and demonstrate poor response to therapy. To date, there have been no reported cases of ovarian cancer with concomitant HIV infection. We describe a young, gravid woman with an advanced ovarian carcinoma diagnosed at the time of delivery. Following poor response to cytoreductive surgery and initial chemotherapy, she was found to be HIV-seropositive. She received multiple chemotherapeutic regimens and experienced significant complications associated with her treatment and HIV infection. She progressively deteriorated and died within 13 months of diagnosis. Based on these findings and experience with other HIV-associated malignancies, it is apparent that the conventional approach to therapy is inadequate to treat the advanced and more aggressive form of disease seen in women infected with HIV.

In vivo processing of an intron-containing archael tRNA.

In vitro studies on the processing of halobacterial tRNA introns have led to the proposal that archaeal and eukaryotic tRNA intron endonucleases have distinctly different requirements for the recognition of pre-tRNAs. Using a Haloferax volcanii in vivo expression vector we have examined the in vivo processing of modified forms of the halobacterial intron-containing tRNA(Trp) gene. As observed in vitro, changes in the exon-intron boundary structure of this pre-tRNA block processing. Intron sequences, other than those at the exon-intron boundaries, are not essential for processing in vivo. We also show that conversion of the tryptophan anticodon to an opal suppressor anticodon is tolerated when the exon-intron boundary structure is maintained.

Diffuse pneumonia and acute respiratory failure due to infectious mononucleosis in a middle-aged adult.

This report describes a 48-yr-old patient who developed bilateral hilar adenopathy, diffuse pulmonary infiltrates, and respiratory failure in association with infectious mononucleosis. Lung and paratracheal lymph node biopsies suggested the diagnosis, and an acute Epstein-Barr virus infection was confirmed serologically. Pulmonary involvement in infectious mononucleosis is reviewed, and atypical features, which may lead to diagnostic difficulty, particularly in the older adult, are discussed.