Antiviral properties of 3-quinolinecarboxamides: a series of novel non-nucleoside antiherpetic agents

Despite the long history in medicine, the pathophysiological mechanism(s) of seasonal affective disorder (SAD) remain largely unknown. By employing a meta-analytic methodology, the authors of this study attempted to verify the validity of different pathophysiological mechanism(s) proposed for SAD. The findings showed that for phototherapy of medium light intensity, a combination of morning-evening therapy regime yielded the best therapeutic effect, and the antidepressant effect of the morning-evening light regime was superior to a single pulse of light administered at other times of day. Furthermore, the data showed that the antidepressant effect of a single pulse of light was similar for morning, midday, and evening light. These findings supported the photon-count hypothesis and refuted the proposed photoperiod, melatonin, and phase-shifting models of SAD.     

Gene for arrhythmogenic right ventricular cardiomyopathy with diffuse nonepidermolytic palmoplantar keratoderma and woolly hair (Naxos disease) maps to 17q21

BACKGROUND: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a heart muscle disease of unknown etiology that causes arrhythmias, heart failure, and sudden death. Diagnosis can be difficult, and this hampers investigation of its molecular basis. Forms of ARVC in which gene penetrance and disease expression are greater should facilitate genetic study. We undertook a clinical and genetic investigation of Naxos disease, originally described by Protonotarios in 1986. This disease constitutes the triad of ARVC, diffuse nonepidermolytic palmoplantar keratoderma, and woolly hair. METHODS AND RESULTS: We evaluated the population of Naxos, Greece, to identify probands, which was followed by family screening. Twenty-one affected persons from 9 families of 150 persons were identified. Linkage analysis was performed with microsatellite markers. The disease locus mapped to 17q21. A peak 2-point LOD score of 3.62 at theta=0.0 was found with a marker within intron 4 of the keratin 9 gene, a member of the type I (acidic) keratin family. A preserved homozygous disease haplotype was identified. Haplotype analysis delimited the disease interval. CONCLUSIONS: Hair and skin abnormalities were found to be reliable markers of subsequent heart disease. This suggests the presence of a single mutant gene with novel cardiac, skin, and hair function or two or more tightly linked disease genes. Recessive inheritance of Naxos disease and a founder effect were demonstrated. Identification of a fully informative genetic marker linked to the disease and uncommon in the background population may be of use as a test to identify disease gene carriers.     

Efficient retroviral-mediated gene transfer to human cord blood stem cells with in vivo repopulating potential

Recent studies have shown efficient gene transfer to primitive progenitors in human cord blood (CB) when the cells are incubated in retrovirus-containing supernatants on fibronectin-coated dishes. We have now used this approach to achieve efficient gene transfer to human CB cells with the capacity to regenerate lymphoid and myeloid progeny in nonobese diabetic (NOD)/severe combined immunodeficiency (SCID) mice. CD34(+) cell-enriched populations were first cultured for 3 days in serum-free medium containing interleukin-3 (IL-3), IL-6, granulocyte colony-stimulating factor, Flt3-ligand, and Steel factor followed by two 24-hour incubations with a MSCV-NEO virus-containing medium obtained under either serum-free or serum-replete conditions. The presence of serum during the latter 2 days made no consistent difference to the total number of cells, colony-forming cells (CFC), or long-term culture-initiating cells (LTC-IC) recovered at the end of the 5-day culture period, and the cells infected under either condition regenerated similar numbers of human CD34(+) (myeloid) CFC and human CD19(+) (B lymphoid) cells for up to 20 weeks in NOD/SCID recipients. However, the presence of serum increased the viral titer in the producer cell-conditioned medium and this was correlated with a twofold to threefold higher efficiency of gene transfer to all progenitor types. With the higher titer viral supernatant, 17% +/- 3% and 17% +/- 8%, G418-resistant in vivo repopulating cells and LTC-IC were obtained. As expected, the proportion of NEO + repopulating cells determined by polymerase chain reaction analysis of in vivo generated CFC was even higher (32% +/- 10%). There was no correlation between the frequency of gene transfer to LTC-IC and colony-forming unit-granulocyte-macrophage (CFU-GM), or to NOD/SCID repopulating cells and CFU-GM (r2 = 0.16 and 0.17, respectively), whereas values for LTC-IC and NOD/SCID repopulating cells were highly and significantly correlated (r2 = 0.85). These findings provide further evidence of a close relationship between human LTC-IC and NOD/SCID repopulating cells (assessed using a >/= 6-week CFC output endpoint) and indicate the predictive value of gene transfer measurements to such LTC-IC for the design of clinical gene therapy protocols.     

Antibiotics: Has the magic gone?

The emergence of antibiotic resistant bacteria has diminished the efficacy of several antibiotics that were used to treat infectious diseases in humans and animals. In recent years, the problem of antibiotic resistance has become more apparent as increasing numbers of bacteria have acquired resistance to multiple antibiotics. Antibiotics inhibit bacterial growth through a variety of mechanisms including inhibition of cell wall or protein synthesis, interference with DNA (or RNA) replication, and disruption of metabolic pathways or cell membrane. Bacteria develop resistance through genetic mutations or by acquiring resistant genes involved in the production of antibiotic degrading enzymes, overproduction of target molecules, efflux pumps to drain out antibiotics, and/or altered cell wall permeability to survive adverse physiological conditions. Published literature suggests that sub‐therapeutic feeding of food animals for growth promotion along with casual use of antibiotics in household products such as soaps and creams is contributing to increased antimicrobial resistance in the environment. If steps are not taken to minimize selective pressure on bacteria, the effectiveness of antibiotics (hailed as ‘magic bullets’) may be marginalized. Important steps in the judicious use of antibiotics on the farm are: (1) education of farmers on the pitfalls of using antibiotics sub‐therapeutically in the production of food animals; (2) development of animal production practices that reduce dependence on antibiotics; and (3) development of manure disposal practices that minimize the spread of residual antibiotics and antibiotic resistant bacteria into the environment. In addition, educating the general public on the use and misuse of antibiotics in daily life is also important if there is to be any significant impact on reducing the environmental spread of antibiotic resistance. Copyright © 2006 Society of Chemical Industry     

Differences in the magnesium dependences of the class I and class II aminoacyl-tRNA synthetases from Escherichia coli

The magnesium dependences of the ATP/PPi exchange and tRNA aminoacylation of reactions were measured for six aminoacyl-tRNA synthetases (isoleucyl-, tyrosyl- and arginyl-tRNA synthetases from class I, and histidyl-, lysyl- and phenylalanyl-tRNA synthetases from class II). The measured values were subjected to best-fit analyses using sum square error calculations between the data and the calculated curves in order to find the mode of participation of the Mg2+ and to optimize the sets of the kinetic constants. The following four dependences were observed: the class II synthetases require three Mg2+ for the activation reaction (including the one in MgATP), but the class I synthetases require only one Mg2+ (in MgATP); in class II synthetases both MgPPi and Mg2PPi participate in the pyrophosphorolysis of the aminoacyl adenylate. Arginyl-tRNA synthetase from class I also shows a better fit if also Mg2PPi reacts, but in the isoleucyl- and tyrosyl-tRNA synthetases only MgPPi but not Mg2PPi is used in the pyrophosphorolysis. Different synthetases have different requirements for the tRNA-bound Mg2+ and spermidine, independent of the enzyme class. 1-4 Mg2+ or spermidines are required in the best fit models. At the end of the reaction in all the synthetases analysed the dissociation of Mg2+ from the product aminoacyl-tRNA essentially enhances the subsequent dissociation of the aminoacyl-tRNA from the enzyme. The binding of ATP to the E. aminoacyl-tRNA complex also speeds up the dissociation of the aminoacyl-tRNA from most of these enzymes.     

Interleukin-10 promotes activation-induced cell death of SLE lymphocytes mediated by Fas ligand

Immune function in SLE is paradoxically characterized by active T cell help for autoantibody production, along with impaired T cell proliferative and cytokine responses in vitro. To reconcile these observations, we investigated the possibility that the accelerated spontaneous cell death of SLE lymphocytes in vitro is caused by an activation-induced cell death process initiated in vivo. 27 SLE patients, three patients with systemic vasculitis, seven patients with arthritis, and 14 healthy subjects were studied. Patients with clinically active SLE or systemic vasculitis had accelerated spontaneous death of PBMC with features of apoptosis at day 5 of culture. A prominent role for IL-10 in the induction of apoptosis was observed, as neutralizing anti-IL-10 mAb markedly reduced cell death in the active SLE patients by 50%, from 22.3 +/- 5.2% to 11.2 +/- 2.8%, and the addition of IL-10 decreased viability in the active SLE group, but not in the control group, by 38%. In addition, apoptosis was shown to be actively induced through the Fas pathway. The potential clinical relevance of T cell apoptosis in active SLE is supported by the correlation of increased apoptosis and IL-10 levels in vitro with low lymphocyte counts in vivo. We conclude that the spontaneous cell death observed in vitro in lymphocytes from patients with SLE and other systemic autoimmune disorders results from in vivo T cell activation, is actively induced by IL-10 and Fas ligand, and reflects pathophysiologically important events in vivo. Activation-induced cell death in vivo provides a pathogenic link between the aberrant T helper cell activation and impaired T cell function that are characteristic features of the immune system of patients with SLE.     

Macrophage oxidative modification of low density lipoprotein occurs independently of its binding to the low density lipoprotein receptor

The oxidative modification of low density lipoproteins (LDL) by arterial wall cells is thought to contribute to atherogenesis. Monocyte/macrophages, among other arterial wall cells, oxidatively modify LDL to a form that is recognized by scavenger/oxidized LDL receptors. It has recently been suggested that LDL binding to the LDL receptor (B/E receptor) is essential for macrophage-mediated oxidation of LDL. In the present study, we compared the ability of resident peritoneal macrophages from LDL-R-deficient (LDLR-/-) mice to oxidize LDL with that of resident peritoneal macrophages from C57B6 mice. The LDLR-/- macrophages oxidized LDL at least as rapidly as did the C57B6 macrophages both in F-10 medium and in Dulbecco's modified Eagle's medium supplemented with 1 microM copper (DMEM-Cu2+). Studies were also conducted to examine the effect of preincubation of LDLR-/- and C57B6 macrophages with 10% lipoprotein-deficient serum (LPDS), which up-regulates LDL receptors, or with acetylated LDL (Ac-LDL), which increases cellular cholesterol and down-regulates LDL receptors. Preincubation with 10% LPDS had no significant effect on subsequent LDL oxidation by either type of cells in F10 medium, but the C57B6 cells did show a small (18%) but significant increase in LDL oxidation in DMEM-Cu2+. Preincubation with 50 micrograms/ml Ac-LDL in F10 medium had no effect on LDL oxidation by either LDLR-/- or C57B6 macrophages. Preincubation with 100 micrograms/ml Ac-LDL had no effect on subsequent LDL oxidation by C57B6 cells but, unexpectedly, caused a modest (26%) fall in LDL oxidation by the receptor-negative cells. Using DMEM-Cu2+ medium, preincubation with Ac-LDL reduced LDL oxidation substantially (50-66%) but the effect was just as great in LDL-R negative cells (59-66%) as in C57B6 cells (50-58%), suggesting that the effect is not due to changes in LDL receptor density. It may be related somehow to the Ac-LDL-induced increase in cell cholesterol content. The data demonstrate that the absence of LDL receptors does not reduce the ability of macrophages to oxidize LDL and that LDL binding to LDL receptors is not an essential requirement for macrophage oxidation of LDL.     

Modeling of correlated failures and community error recovery inmultiversion software

Three aspects of the modeling of multiversion software are considered. First, the beta-binomial distribution is proposed for modeling correlated failures in multiversion software. Second, a combinatorial model for predicting the reliability of a multiversion software configuration is presented. This model can take as inputs failure distributions either from measurements or from a selected distribution (e.g. beta-binomial). Various recovery methods can be incorporated in this model. Third, the effectiveness of the community error recovery method based on checkpointing is investigated. This method appears to be effective only when the failure behaviors of program versions are lightly correlated. Two different types of checkpoint failure are also considered: an omission failure where the correct output is recognized at a checkpoint but the checkpoint fails to correct the wrong outputs and a destructive failure where the good versions get corrupted at a checkpoint     

Distinct developmental patterns of short-term and long-term functioning lymphoid and myeloid precursors defined by competitive limiting dilution analysis in vivo

Functional abilities of individual marrow precursor cells were defined by competitive limiting dilution without enrichment, tissue culture, or induced marking, manipulations that might affect cell functions. We directly measured long-term repopulating abilities in limiting doses (0.25-1.0 x 10(5)) of genetically marked congenic marrow cells. These were mixed with a standard dose of 4 or 5 x 10(5) competitor marrow cells, which contained a predictable distribution of precursor cells and allowed quantitative assays. Percentages of donor type T and B lymphocytes, granulocytes, platelets, and erythrocytes were measured in recipient blood. Applying the maximum likelihood statistic, concentrations (per 10(5)) of precursors repopulating at least one lineage were: 4.7 and 6.0 after 6 wk, 1.6 and 2.7 after 14 to 15 wk, and 1.2 and 1.9 after 30 to 32 wk; concentrations repopulating at least three lineages were 2.3 and 3.4 after 6 wk, 0.9 and 1.7 after 14 to 15 wk, and 0.9 and 1.3 after 32 wk. Almost all precursors functioning after 14 wk repopulated all lineages. At 6 wk, similar levels of donor cells were produced in recipients of both short- and long-term precursors. However, after 14 to 32 wk, contributions by short-term precursors (about two-thirds of the precursors) dropped to zero, while contributions by long-term precursors (about one-quarter of the precursors) expanded severalfold. The latter permanently repopulated all lineages after 30 to 32 wk, functioning as the most primitive stem cells (PSC) in the immune and myeloid systems. Nearly all the variance in long-term repopulated recipients was explained using the Poisson distribution to calculate donor percentages in a model where each donor and competitor PSC contributed equally.