NADH-ubiquinone oxidoreductase activity in the kinetoplasts of the plant trypanosomatid<Emphasis Type="Italic"> Phytomonas serpens</Emphasis>

NADH-ubiquinone oxidoreductase activity is present in mitochondrial lysates of Phytomonas serpens. Rotenone at 2–10 M inhibited the activity 50–75%, indicating that it belongs to respiratory complex I. The activity was also inhibited 50–60% in the presence of 10–30 nM atovaquone suggesting that inhibition of complex I represents a likely mechanism of the known antileishmanial activity of this drug. The complex was partially purified by chromatography on DEAE-Sepharose CL-6B and gel-filtration on Sepharose CL-2B. The NADH:ubiquinone oxidoreductase activity in this preparation was completely inactivated by 20 nM atovaquone. The partially purified complex was present in a low amount and its subunits could not be discerned by staining with Coomassie. However, one of its components, a homologue of the 39 kDa subunit of the bovine complex I, was identified immunochemically in the original lysate and in the partially purified material.     

Quantitative analysis of synaptic distribution along thalamocortical axons in adult mouse barrels

Quantitative data on thalamocortical synapses in adult mouse barrels have been obtained largely by using lesion-nduced degeneration to label thalamic afferents. By the time degenerating axons can be identified with the electron microscope, they have broken up into many separate pieces, making it impossible to assess the distribution of synapses along unbroken lengths of afferent. Here, this deficiency is rectified by examining intact lengths of axon labeled by the injection of biotinylated dextran amine into ipsilateral thalamus. Serial thin section reconstructions were analyzed to determine the numbers of synapses per axon length made with dendritic spines vs. shafts and the locations of synapses with respect to axonal varicosities. Results for seven axonal segments from six mice showed an average of 0.2 synapses/microm; 80% were made with spines and 20% with dendritic shafts. Just over two-thirds of axonal varicosities formed one synapse; most of the remainder formed two and rarely three, whereas 8% formed none. Although most synapses occurred at varicosities (88%), more than 12% were made at cylindrically shaped regions of the reconstructed axonal segments. These results serve as a caveat for the use of light microscopy to quantify synapses, wherein the usual approach is to equate one varicosity with one synapse. For thalamocortical afferents to mouse barrels, equating one varicosity with one synapse would prove to be incorrect more than 30% of the time and would exclude the roughly 12% of synaptic connections made at cylindrical regions of thalamocortical afferents.     

Bounds and normalization of the composite linkage disequilibrium coefficient

The composite linkage disequilibrium (LD) measure is often calculated for two-locus genotypic data, especially when coupling and repulsion double heterozygotes cannot be distinguished. This measure was reported to have good statistical properties and was suggested for routine testing of LD, regardless of Hardy-Weinberg equilibrium at either of two loci. However, the bounds for this measure have not been yet reported. These bounds are derived here as functions of one-locus genotype or allele frequencies. They provide standardized measures of composite linkage disequilibrium, defined as the proportion of its maximum attainable value, given observed allele or genotype frequencies.     

Debulking surgery for patients with diffuse large B-cell non-Hodgkin's lymphoma

Chemotherapy and radiotherapy have been the principal modalities of treatment for diffuse large B-cell non-Hodgkin's lymphoma (B-NHL) for over 30 years. Various treatment regimens have been designed over the years to try to increase response and cure rates. The role of surgery has been generally restricted to defined and limited situations including diagnostic tissue biopsies and treating abdominal emergencies such as organ rupture or perforation. We present two cases of refractory B-NHL, where surgery was used as a part of stepwise and multi-modal treatment with curative intent. In both cases, the treatment approach included standard dose chemotherapy, eradication of residual mass by surgery, high dose chemotherapy (HDC) with stem cell support and posttransplantant immunotherapy. Currently, 2 years after completing the therapy, both patients are well with no evidence of active disease. Based on our experience with 2 patients we believe that in specific cases of residual chemo-resistant lymphomatous mass, surgery should be considered as a part of a multimodal approach.     

Pronuclear morphology evaluation with subsequent evaluation of embryo morphology significantly increases implantation rates

OBJECTIVE: To elucidate the relative predictive value of implantation markers at different stages of preimplantation development. DESIGN: Correlation of pronuclear morphology with embryo morphology and implantation rates in retrospective and prospective analysis of in vitro fertilization/intracytoplasmic sperm injection (IVF-ICSI) treatment cycles. SETTING: Private infertility center. PATIENT(S): A total of 441 couples undergoing infertility treatment. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Size of pronuclei and distance between them, the number and polarization of nucleolus precursor bodies (NPB) at the one-cell stage, embryo cleavage and fragmentation rates on days 2 and 3, and pregnancy and implantation rates. RESULT(S): Polarization of the NPB in both pronuclei had a statistically significant correlation with normal membrane breakage during ICSI (40%, compared with 33% easy, and 31% difficult membrane breakage) and also with faster cleavage and lower fragmentation rates of embryos. Sixty-one percent of implanting embryos had polarization of the NPB in both pronuclei compared with 37% for all embryos. Larger distance between pronuclei and their unequal size had a statistically significant correlation with slower cleavage and inferior embryo quality. Embryo selection based on only pronuclear morphology or on only day-3 embryo morphology yielded implantation rates of 15.1% and 12.1%, respectively. Embryo selection based on sequential evaluation of both pronuclear morphology and embryo morphology on day 3 resulted in a 21.1% implantation rate. CONCLUSION(S): Polarization of NPB in both pronuclei is as reliable marker of implantation as embryo morphology on day 3. However, pronuclear morphology assessment improves embryo selection only when it is combined with embryo morphology evaluation on day 3.     

Constitutive EGFR signaling confers a motile phenotype to neural stem cells

The epidermal growth factor receptor (EGFR) has been shown to play an important role in brain development, including stem and precursor cell survival, proliferation, differentiation, and migration. To further examine the temporal and spatial requirements of erbB signals in uncommitted neural stem cells (NSCs), we expressed the ligand-independent EGF receptor, EGFRvIII, in C17.2 NSCs. These NSCs are known to migrate and to evince a tropic response to neurodegenerative environments in vivo but for which an underlying mechanism remains unclear. We show that enhanced erbB signaling via constitutive kinase activity of EGFRvIII in NSCs sustains an immature phenotype and enhances NSC migration.     

Synthesis and structure-activity relationship of 4-substituted 2-(2-acetyloxyethyl)-8-(morpholine-4-sulfonyl)pyrrolo[3,4-c]quinoline-1,3-diones as potent caspase-3 inhibitors

Synthesis, biological evaluation, and SAR dependencies for a series of novel 1,3-dioxo-2,3-dihydro-1H-pyrrolo[3,4-c]quinoline inhibitors of caspase-3 are described. The inhibitory activity of the synthesized compounds is highly dependent on the nature of 4-substituents on the core scaffold. 4-methyl-and 4-phenyl-substituted derivatives, which were the most active compounds within this series, inhibited caspase-3 with IC50 of 23 and 27 nM, respectively.     

Alcohol use and HIV risk behaviors among HIV-infected hospitalized patients in St. Petersburg, Russia

PURPOSE: Russia has high per capita alcohol consumption and an injection-drug-use-driven HIV epidemic. However, the role of alcohol in the spread of HIV infection in Russia is largely unexplored. Thus, we assessed recent alcohol use and associated HIV risk behaviors among HIV-infected persons in St. Petersburg, Russia. METHODS: We recruited HIV-infected hospitalized patients from the Botkin Infectious Disease Hospital between June 2001 and March 2002. Interviewers assessed alcohol and drug use with the addiction severity index (ASI) and sex- and drug-risk behaviors with the risk assessment battery (RAB). Lifetime abuse or dependence diagnoses for alcohol and drugs were established by a physician with addiction medicine training. RESULTS: Among 201 subjects, diagnoses of abuse or dependence (AB/DEP) were common: 9% (19/201) had only alcohol AB/DEP; 39% (78/201) had alcohol and drug AB/DEP; 47% (95/201) had only drug AB/DEP; and 4% (9/201) had no diagnosis of alcohol or drug AB/DEP. Sex- and drug-risk behaviors varied significantly by substance use diagnosis. Subjects with any alcohol AB/DEP had higher sex-risk RAB scores than those with drug only AB/DEP (6.1 versus 3.9, p<.0001). Among subjects with any diagnosis of drug AB/DEP, having in addition an alcohol diagnosis was associated with unclean needle use in the last six months (33% (26/78) versus 21% (20/95), p=0.08). CONCLUSIONS: Lifetime alcohol diagnoses of abuse or dependence were present in nearly one-half of hospitalized HIV-infected patients in St. Petersburg, Russia and were associated with significantly higher sex-risk behaviors and borderline significantly higher drug-risk behaviors. As HIV infection spreads rapidly in Russia and Eastern Europe, these data support the need for HIV risk-reduction interventions in alcohol abusing populations and raise the potential of benefit by addressing alcohol use in HIV-infected populations.