Cyclin A and B functions in the early Drosophila embryo.

In eukaryotes, mitotic cyclins localize differently in the cell and regulate different aspects of the cell cycle. We investigated the relationship between subcellular localization of cyclins A and B and their functions in syncytial preblastoderm Drosophila embryos. During early embryonic cycles, cyclin A was always concentrated in the nucleus and present at a low level in the cytoplasm. Cyclin B was predominantly cytoplasmic, and localized within nuclei only during late prophase. Also, cyclin B colocalized with metaphase but not anaphase spindle microtubules. We changed maternal gene doses of cyclins A and B to test their functions in preblastoderm embryos. We observed that increasing doses of cyclin B increased cyclin B-Cdk1 activity, which correlated with shorter microtubules and slower microtubule-dependent nuclear movements. This provides in vivo evidence that cyclin B-Cdk1 regulates microtubule dynamics. In addition, the overall duration of the early nuclear cycles was affected by cyclin A but not cyclin B levels. Taken together, our observations support the hypothesis that cyclin B regulates cytoskeletal changes while cyclin A regulates the nuclear cycles. Varying the relative levels of cyclins A and B uncoupled the cytoskeletal and nuclear events, so we speculate that a balance of cyclins is necessary for proper coordination during these embryonic cycles.

Biomedical and psychosocial predictors of early rehospitalization among children with insulin-dependent diabetes mellitus: a longitudinal study.

The purpose of the present study was to determine the cumulative probability of the first diabetes-related rehospitalization within the initial 2.5 years after the onset of insulin-dependent diabetes mellitus (IDDM) among newly diagnosed children, and to identify risk factors that can be determined shortly after IDDM-onset. The sample consisted of 88 children, 8 to 13 years old at the onset of IDDM, who had been participating in a longitudinal study. In this sample, there was a 0.25 cumulative probability of an early readmission. Poor control was the most frequent reason for readmissions. Four variables significantly increased the risk of early rehospitalization: severity of child's externalizing symptoms at IDDM-onset, lower socio-economic status, younger age at onset of IDDM, and higher levels of glycosylated haemoglobin, reflecting poorer metabolic control. Because externalizing symptoms and poor control are amenable to change, some early rehospitalizations can potentially be prevented. Furthermore, information about the risk of early rehospitalization should be part of initial diabetes education in order to better prepare families for the possibility of such an event.

Suicidal ideation and suicide attempts among youth with insulin-dependent diabetes mellitus.

OBJECTIVE: To investigate the prevalence and correlates of suicidal behaviors among youth with insulin-dependent diabetes mellitus (IDDM) for up to 12 years after disease onset. METHOD: The occurrence of suicidal ideation and suicide attempts was assessed shortly after disease onset and repeatedly thereafter as part of a longitudinal study of diabetic children. Initial psychiatric status and symptomatology, characteristics of the medical illness, and sociodemographic variables were considered as potential correlates of suicidal behaviors. RESULTS: Young patients evidenced higher than expected rates of suicidal ideation, but relatively few attempted suicide over the follow-up. Among those who did attempt suicide, diabetes-related methods commonly were used. Suicidal ideation shortly after IDDM onset was related only to concurrent severity of depressive symptoms. Suicidal ideation over the follow-up was associated with later noncompliance with the medical regimen. CONCLUSIONS: Clinicians should be alert to the possibility of suicidal ideation among youth with IDDM because of the prevalence of those cognitions, the potential lethality of attempts due to insulin misuse, and the relationship of suicidal thoughts to later noncompliance with the medical regimen.