Myt1: a membrane-associated inhibitory kinase that phosphorylates Cdc2 on both threonine-14 and tyrosine-15

Cdc2 is the cyclin-dependent kinase that controls entry of cells into mitosis. Phosphorylation of Cdc2 on threonine-14 and tyrosine-15 inhibits the activity of the enzyme and prevents premature initiation of mitosis. Although Wee1 has been identified as the kinase that phosphorylates tyrosine-15 in various organisms, the threonine-14-specific kinase has not been isolated. A complementary DNA was cloned from Xenopus that encodes Myt1, a member of the Wee1 family that was discovered to phosphorylate Cdc2 efficiently on both threonine-14 and tyrosine-15. Myt1 is a membrane-associated protein that contains a putative transmembrane segment. Immunodepletion studies suggested that Myt1 is the predominant threonine-14-specific kinase in Xenopus egg extracts. Myt1 activity is highly regulated during the cell cycle, suggesting that this relative of Wee1 plays a role in mitotic control.     

Enthalpy relaxation of reactive graphitic nanofibers reinforced epoxy

The enthalpy relaxation of an epoxy resin modified by three different concentrations of reactive-Graphitic Nanofibers (r-GNFs) has been investigated by standard and modulated differential scanning calorimetry (DSC). From DSC scan at 10 °C/min following cooling at various rates through the transition region, the apparent activation energy, Δh*, was evaluated. The non-linearity parameter, χ, was analyzed by the peak shift method for samples annealed at temperature T _g −20 °C for different period of time (up to 167 h). The non-exponentiality parameter, β, was determined based on the inflectional slope of the complex heat capacity. The experimental results showed that the incorporation of r-GNFs into epoxy network causes greater non-linearity, higher apparent activation energy, and broader relaxation time distribution than the neat epoxy resin. These values were optimum for epoxy resin with 0.3 wt% of r-GNFs.     

Driving anger, sensation seeking, impulsiveness, and boredom proneness in the prediction of unsafe driving

The present study investigated the potential contribution of sensation seeking, impulsiveness, and boredom proneness to driving anger in the prediction of aggressive and risky driving. Two hundred and twenty-four college student participants completed measures of trait driving anger, aggressive and risky driving, driving anger expression, sensation seeking, impulsiveness, and boredom proneness. Findings provided additional support for the utility of the Driving Anger Scale (DAS; Deffenbacher, J.L., Oetting, E.R., Lynch, R.S., Development of a driving anger scale, Psychological Reports, 74, 1994, 83-91.) in predicting unsafe driving. In addition, hierarchical multiple regression analyses demonstrated that sensation seeking, impulsiveness, and boredom proneness provided incremental improvements beyond the DAS in the prediction of crash-related conditions, aggressive driving, risky driving, and driving anger expression. Results support the use of multiple predictors in understanding unsafe driving behavior.     

Separation of sperm and epithelial cells in a microfabricated device: potential application to forensic analysis of sexual assault evidence

Forensic DNA analysis of sexual assault evidence requires separation of DNA from epithelial (victim) and sperm (perpetrator) cells. The conventional method used by crime laboratories, which is termed "differential extraction", is a time-consuming process. To supplant the conventional process, separation of sperm from a biological mixture containing epithelial cells has been demonstrated on a microfluidic device. This separation utilizes the differential physical properties of the cells that result in settling of the epithelial cells to the bottom of the inlet reservoir and subsequent adherence to the glass substrate. As a result, low flow rates can be used to separate the sperm cells from the epithelial cell-containing biological mixture. Following cell separation on the microdevice, DNA extraction, amplification, and separation were performed using conventional laboratory methods, showing that the cell separation product in the outlet reservoir was of male origin. The reported cell separation has the potential to impact the forensic DNA analysis backlog of sexual assault cases by circumventing the time-consuming conventional differential extraction procedure.     

Leukemic phase of mantle cell lymphoma presenting as anemia: diagnosis by combining flow cytometry and cytomorphology

We report a case of mantle cell lymphoma in leukemic phase, which was diagnosed by a bone marrow biopsy performed as part of a workup for chronic anemia in a patient without lymphadenopathy. The patient, a 79-year-old man with diabetes mellitus, hypertension, chronic renal failure, congestive heart failure, and atherosclerosis, presented with claudication. On admission, he also had an 8-month history of anemia, during which time he experienced a 18-kg weight loss. On presentation, the patient had normal vital signs, anemia, leukocytosis (as well as an absolute lymphocytosis), and splenomegaly; as mentioned, lymphadenopathy was absent. A bone marrow biopsy showed an increase in small to intermediate-sized, slightly irregular lymphocytes in interstitial nodules. Flow cytometric immunophenotyping of the bone marrow identified a monoclonal population of cells, representing 25% of cells within the bone marrow, with expression of CD19, CD20, immunoglobulin M/D, lambda light chain, HLA-DR, and CD5; reactions for CD10 and CD23 were absent. Based on morphologic and immunophenotypic analysis of the bone marrow, as well as morphologic review of the peripheral blood smear, a diagnosis of mantle cell lymphoma involving the bone marrow and in leukemic phase was made. Subsequent polymerase chain reaction analysis of DNA from peripheral blood identified a population of cells with the bcl-1 rearrangement. This case is unique in that the diagnosis of mantle cell lymphoma was made without lymph node or spleen analysis and the patient, although exhibiting bone marrow and peripheral blood involvement by mantle cell lymphoma at presentation, did not have lymphadenopathy.