Requirement for a phospholipase C in odor response: overlap between olfaction and vision in Drosophila.

A central problem in sensory system biology is the identification of the signal transduction pathways used in different sensory modalities. Genetic analysis of transduction mutants provides a means of studying in vivo the contributions of different pathways. This report shows that odorant response in one olfactory organ of Drosophila melanogaster depends on the norpA phospholipase C (EC 3.1.4.3) gene, providing evidence for use of the inositol 1,4,5-trisphosphate (IP3) signal transduction pathway. Since the norpA gene is also essential to phototransduction, this work demonstrates overlap in the genetic and molecular underpinnings of vision and olfaction. Genetic and molecular data also indicate that some olfactory information flows through a pathway which does not depend on norpA.     

Adenosine diphosphate strongly potentiates the ability of the chemokines MDC, TARC, and SDF-1 to stimulate platelet function

Platelet activation is normally induced by primary agonists such as adenosine diphosphate (ADP), thrombin, and collagen, whereas other agonists, such as epinephrine, can play important accessory roles. It is now reported that the macrophage-derived chemokine (MDC), thymus activation-regulated chemokine (TARC), and stromal cell-derived factor one (SDF-1) are highly effective activators of platelet function under a variety of conditions, stimulating platelet shape change, aggregation, and adhesion to collagen or fibrinogen. Chemokine-mediated platelet activation was rapid and maximal (less than 5 seconds) under arterial flow conditions and depended strongly on the presence of low levels of primary agonists such as ADP or thrombin. Concentrations of ADP (0.05-0.25 microM) or thrombin (0.005-0.02 U/mL) that induced minimal aggregation caused major aggregation acting in combination with the chemokines. The ability of apyrase to block chemokine-dependent aggregation or adhesion was consistent with an important role for ADP. Chemokine-stimulated aggregation was also insensitive to indomethacin, suggesting that the activation of cyclo-oxygenase is not involved. TARC, MDC, and SDF-1 increased intracellular calcium concentrations [Ca(2+)](i) when combined with low levels of ADP. The MDC and TARC receptor CCR4 was expressed on platelets, and an anti-CCR4 antibody blocked aggregation induced by TARC or MDC. Treatment of platelets with SDF-1 and MDC rapidly exposed P-selectin (CD62P) on the cell surface but did not induce the secretion of serotonin. These findings suggest that the chemokines MDC, TARC, and SDF-1, which may be produced during inflammatory responses, coupled with low levels of ADP or thrombin, can serve as strong stimuli for activating platelet function.     

The role of quantum mechanics in structure-based drug design

Herein we will focus on the use of quantum mechanics (QM) in drug design (DD) to solve disparate problems from scoring protein-ligand poses to building QM QSAR models. Through the variational principle of QM we know that we can obtain a more accurate representation of molecular systems than classical models, and while this is not a matter of debate, it still has not been shown that the expense of QM approaches is offset by improved accuracy in DD applications. Objectively validating the improved applicability and performance of QM over classical-based models in DD will be the focus of research in the coming years along with research on the conformational sampling problem as it relates to protein-ligand complexes.     

Disposition kinetics in dogs of diethyldithiocarbamate,a metabolite of disulfiram

Following the intravenous infusion of sodium diethyldithiocarbamate to dogs, the disposition kinetics of diethyldithiocarbamate (DDC), a metabolite of disulfiram, were assessed. Approximately 27% of the administered dose was S-methylated, this process exhibiting a mean first-order rate constant of 0. 0569 min^–1 (t_1/2=12.2 min), while the remainder was eliminated by other routes having a rate constant of 0.148 min^–1 (t_1/2=4.68 min). The methyl diethyldithiocarbamate (MeDDC) formed from DDC showed an elimination rate constant of 0.0141 min^–1 (t_1/2=49.2 min). These observations are discussed in the light of previous investigations where the presence of MeDDC has rarely been sought or reported. A few comparisons with prior studies, in which DDC or disulfiram was administered, are made by retrospective kinetic evaluation of published data. The results are discussed in relation to the duration of action of disulfiram in man.Glossary A plasma concentration intercept at the cessation of infusion (mass/volume) - A _T simplifying constant (mass/volume/time) - AUC _M area under the plasma concentration-time curve for MeDDC (mass × time/volume) - b time variable; equalst during infusion, equalsT after the cessation of infusion - B plasma concentration intercept at the cessation of infusion (mass/volume) - B _T simplifying constant (mass/volume/time) - C _D plasma concentration of DDC at any timet (mass/volume) - C _M plasma concentration of MeDDC, expressed as DDC, at any timet (mass/volume) - C _T plasma concentration of total DDC, expressed as DDC, at any timet;C _T=C_D+C_M (mass/volume) - C _t plasma concentration of total DDC, expressed as DDC, at any timet (mass/volume) - Cl _D total body clearance of DDC (volume/time) - Cl _M total body clearance of MeDDC (volume/time) - DDC diethyldithiocarbamate - f fraction of DDC that is methylated;f=K _DM/K _D - K _A apparent first-order rate constant (reciprocal time) - K _B apparent first-order rate constant (reciprocal time) - K _D apparent first-order rate constant for the elimination of DDC by all routes (reciprocal time) - K _M apparent first-order rate constant for the elimination of MeDDC by all routes (reciprocal time) - K _DE apparent first-order rate constant for the elimination of DDC by all routes except methylation (reciprocal time) - K _DM apparent first-order rate constant for theS-methylation of DDC (reciprocal time) - MeDDC methyl diethyldithiocarbamate - NaDDC sodium diethyldithiocarbamate (trihydrate) - Q zero-order infusion rate constant (mass/time) - Q ₁ zero-order infusion rate constant for the faster of two consecutive infusions (mass/time) - Q ₂ zero-order infusion rate constant for the slower of two consecutive infusions (mass/time) - t elapsed time since dosing (e.g., infusion) commenced - t elapsed time since the cessation of infusion - T duration of infusion (time) - T ₁ duration of the faster of two consecutive infusions (time) - T ₂ total duration of infusion when two consecutive infusions are administered (time) - V _D apparent volume of distribution of DDC - V _M apparent volume of distribution of MeDDC This work was supported by the Atkinson Charitable Foundation (Toronto, Ontario, Canada) and the Non-Medical Use of Drugs Directorate, Health and Welfare Canada (Grant No. 1212-5-206).     

Fetal bladder rupture due to anteriorurethral valves

A rupture of the fetal bladder that resulted in urinary ascites has rarely been reported in published studies. We present the first case of a spontaneous rupture of the fetal bladder, due to an anterior urethral valve, in which the diagnosis was suspected prenatally by means of Doppler ultrasonography and was confirmed postnatally.     

Molecular characterization of Vibrio cholerae O1 outbreak strains in Miri,Sarawak (Malaysia)

Bacterial resistance to various antimicrobial agents is common in area with high usage of antibiotics. In this study, the data on antimicrobial susceptibility patterns of Vibrio cholerae O1 from patients during an outbreak period was found to be high but variable rates of multidrug resistance. Thirty-two of 33 V. cholerae isolates harboured the tcp, ctx, zot and ace genes, suggesting their possible roles in the outbreak cases. We analyzed the molecular diversity of a total of 33 strains of V. cholerae O1 isolated from 33 patients between November 1997 and April 1998 using random amplified polymorphic DNA (RAPD) analysis. The 30 typable isolates could be separated into four major clusters containing 5, 17, 2 and 6 isolates, respectively. However, no particular RAPD pattern was predictive of a particular pattern of antibiotic susceptibility. The findings of this study showed that multiple clones seemed to be responsible for cases in the outbreaks in the study area.     

Hypertensive encephalopathy as a complication of hyperdynamic therapy for vasospasm: report of two cases

OBJECTIVE AND IMPORTANCE: After developing subarachnoid hemorrhage, patients may deteriorate from a variety of well-known causes, including rebleeding, hydrocephalus, and vasospasm. Many patients now undergo empirical hyperdynamic vasospasm therapy with hypervolemia, induced hypertension, and nimodipine. CLINICAL PRESENTATION: We report two cases of iatrogenic hypertensive encephalopathy occurring during hyperdynamic therapy for cerebral vasospasm after subarachnoid hemorrhage. Hypertensive encephalopathy is a syndrome of rapidly evolving generalized or focal cerebral symptoms occurring in the setting of severe hypertension, which is reversible with antihypertensive therapy. INTERVENTION: The syndrome can be diagnosed in the appropriate clinical setting with computed tomographic or magnetic resonance imaging that demonstrates characteristic findings. In both cases, decreasing the blood pressure resulted in neurological improvement. CONCLUSION: In the setting of induced hypertensive/hypervolemic therapy for vasospasm, hypertensive encephalopathy should be considered as a potentially reversible cause of delayed neurological decline.     

French trainees in obstetrics and gynaecology theoretical training and practice of vaginal breech delivery: a national survey

OBJECTIVE: To survey French trainees in Obstetrics and Gynaecology and evaluate their theoretical training and practice of vaginal breech delivery (VBD). STUDY DESIGN: We conducted a national survey between January and April 2004 among the 817 French trainees undergoing a 5-year training program in obstetrics and gynaecology. Trainees in years 1-3 were considered as juniors, and those in years 4 and 5 as seniors. Respondents were invited to specify whether they had received theoretical teaching in the management of VBD, and to indicate the number of VBDs they had performed during their training. RESULTS: The questionnaire was returned by 156 (19%) trainees and of these 140 questionnaires were suitable for analysis. Overall, 35% of the respondents had never been taught the management of a VBD. Among the senior trainees, 33% had performed less than four VBDs, and 23% had not received any teaching on how to manage a VBD. CONCLUSION: The level of theoretical training and practice in the management of VBD seems to have diminished and does not bring the French trainees in obstetrics and gynaecology to the required standard of competence.