Two new variants of G6PD deficiencies in Singapore

Identification of mutations in G6PD gene is performed as an epidemiologic investigation of G6PD deficiency in many countries. In order to understand the hereditary background of G6PD deficiency in a population, screening of mutations is required not only in exonic regions but also for intron and promoter regions. One hundred male neonatal samples diagnosed as with G6PD deficiency by newborn screening in Singapore were used in this study. The multiplex PCR using the multiple tandem forward primers and common reverse primer (MPTP) method was carried out to detect the common 11 mutations in south-east Asia such as Gaohe 95A>G, Orissa 131C>G, Vanua-Lava 383T>C, Mahidol 487G>A, Mediterranean 563C>T, Coimbra 592C>T, Viangchan 871G>A, Chatham 1003G>A, Union 1360C>T, Canton 1376G>T and Kaiping 1388G>A. Samples whose mutations were unidentified by MPTP method were scanned at cording region, intron and promoter region by direct sequencing.Out of 100 samples, 90 samples (90.0%) were identified with one of the above mentioned common mutations. Eight out of 10 samples whose mutations were unidentified by MPTP method carried exonic mutations which had been previously reported such as Murcia 209A>G, Quing Yuan 392G>T, Nankang 517T>C, Chinese5 1024C>T. Two novel mutations were identified in these samples: one had a novel mutation (25C>T); the remaining sample carried a 49 bp deletion in intron 12.

Operation of a 500 MHz high temperature superconducting NMR: towards an NMR spectrometer operating beyond 1 GHz

We have begun a project to develop an NMR spectrometer that operates at frequencies beyond 1 GHz (magnetic field strength in excess of 23.5 T) using a high temperature superconductor (HTS) innermost coil. As the first step, we developed a 500 MHz NMR with a Bi-2223 HTS innermost coil, which was operated in external current mode. The temporal magnetic field change of the NMR magnet after the coil charge was dominated by (i) the field fluctuation due to a DC power supply and (ii) relaxation in the screening current in the HTS tape conductor; effect (i) was stabilized by the 2H field-frequency lock system, while effect (ii) decreased with time due to relaxation of the screening current induced in the HTS coil and reached 10(-8)(0.01 ppm)/h on the 20th day after the coil charge, which was as small as the persistent current mode of the NMR magnet. The 1D (1)H NMR spectra obtained by the 500 MHz LTS/HTS magnet were nearly equivalent to those obtained by the LTS NMR magnet. The 2D-NOESY, 3D-HNCO and 3D-HNCACB spectra were achieved for ubiquitin by the 500 MHz LTS/HTS magnet; their quality was closely equivalent to that achieved by a conventional LTS NMR. Based on the results of numerical simulation, the effects of screening current-induced magnetic field changes are predicted to be harmless for the 1.03 GHz NMR magnet system.

Identification of Piccolo as a regulator of behavioral plasticity and dopamine transporter internalization

Dopamine transporter (DAT) internalization is a mechanism underlying the decreased dopamine reuptake caused by addictive drugs like methamphetamine (METH). We found that Piccolo, a presynaptic scaffolding protein, was overexpressed in the nucleus accumbens (NAc) of the mice repeatedly administrated with METH. Piccolo downexpression by antisense technique augmented METH-induced behavioral sensitization, conditioned reward and synaptic dopamine accumulation in NAc. Expression of Piccolo C2A domain attenuated METH-induced inhibition of dopamine uptake in PC12 cells expressing human DAT. Consistent with this, it slowed down the accelerated DAT internalization induced by METH, thus maintaining the presentation of plasmalemmal DAT. In immunostaining and structural modeling Piccolo C2A domain displays an unusual feature of sequestering membrane phosphatidylinositol 4,5-bisphosphate, which may underlie its role in modulating DAT internalization. Together, our results indicate that Piccolo upregulation induced by METH represents a homeostatic response in the NAc to excessive dopaminergic transmission. Piccolo C2A domain may act as a cytoskeletal regulator for plasmalemmal DAT internalization, which may underlie its contributions in behavioral plasticity.

Evaluation of cholesterol content and impact on antigen exposure in the outer lipid bilayer of adult schistosomes

Developing and adultSchistosoma mansoniandS. haematobiumintact worms do not bind specific antibodies, likely because of structural and biochemical modifications of the outer lipid bilayer. We have estimated the amount of cholesterol in the apical membrane of adult schistosomes via extraction with the membrane-impermeable, cholesterol-binding drug, methyl-β-cyclodextrin (MBCD), followed by filipin staining of the worms, and evaluation of the amount of cholesterol released in the medium by a commercially available, enzymatic colorimetric assay. Positive correlations between amount of released cholesterol, MBCD concentration, and worm number and age provided evidence for the sensitivity and validity of the newly developed method. Treatment with 40 mmMBCD for 2 h at 37°C led to total loss of cholesterol from the worm outer membrane, as assessed by filipin staining, and the released cholesterol values were used to estimate the amount of cholesterol per worm and per an approximate surface area unit. Additionally, total depletion of outer membrane cholesterol was associated with exposure of surface membrane antigens to specific antibody binding in 50% and 70% ofS. haematobiumandS. mansoniworms, respectively. These findings together suggest that cholesterol is an essential, but not the sole, factor in sequestration of surface membrane antigens in schistosomes.

Induction of endonuclease G-mediated apopotosis in human oral squamous cell carcinoma cells by protein kinase C inhibitor safingol

PKC inhibitor safingol suppressed the growth of human oral squamous cell carcinoma (SCC) cells significantly at concentrations that inhibit PKC isoforms. Safingol inhibited the translocation of PKC following treatment with 12-o-tetradecanoylphorbol 13-acetate (TPA) in PKC alpha-EGFP-transfected cells, but not in PKC beta-EGFP- transfected cells, indicating selective inhibition for PKC alpha in oral SCC cells. Flow cytometric analysis and DNA analysis by agarose gel electrophoresis revealed an increase in the proportion of sub-G(1) cells and DNA fragmentation in safingol-treated cells. Mitochondrial membrane potential was decreased, and cytochrome c was released from mitochondria. However, the safingol-induced cell death was not accompanied by activation of caspase 3 and cleavage of poly (ADP-ribose) polymerase (PARP). The broad-spectrum caspase inhibitor BD-fmk failed to prevent safingol-induced cell death. Another apoptogenic factor endonuclease G, but not apoptosis-inducing factor (AIF), was also released from mitochondria and translocated to the nucleus. These results suggest that PKC alpha inhibitor safingol induces an endonuclease G- mediated apoptosis in a caspase-independent manner.

Different real-time PCR assays could lead to a different result of detection of varicella-zoster virus in facial palsy

Real-time PCR is a useful tool for rapid detection of viral genomic DNA. However, there are many types of real-time PCR, and this variation may induce different results. The sensitivity of two different real-time PCR assays was evaluated for the detection of the varicella-zoster virus (VZV) genome: LightCycler PCR and TaqMan PCR. Auricular skin cells and saliva were sampled from 201 patients with facial nerve paralysis. A hundred and seventy-one of these patients were diagnosed clinically with Bell's palsy, and the remaining 30 with Ramsay Hunt syndrome. In 30 specimens obtained from Ramsay Hunt syndrome patients, VZV DNA was detected in 26 skin and 3 saliva specimens using the LightCycler PCR, while 28 skin and 9 saliva specimens were positive using the TaqMan PCR. None of the patients with Bell's palsy were positive for VZV by the LightCycler PCR, whereas five of these patients were positive by the TaqMan PCR. The TaqMan PCR assay has a better sensitivity compared to the LightCycler PCR for the detection of VZV genome from patients with facial palsy. Further study is required to develop a more sensitive real-time PCR.

Nicotine regulates DARPP-32 (dopamine- and cAMP-regulated phosphoprotein of 32 kDa) phosphorylation at multiple sites in neostriatal neurons

Nicotinic acetylcholine receptors (nAChRs) regulate dopaminergic signaling in the striatum by modulating the release of neurotransmitters. We have recently reported that nicotine stimulates the release of dopamine via alpha4beta2(*) nAChRs and/or alpha7 nAChRs, leading to the regulation of DARPP-32 at Thr34, the site involved in regulation of protein phosphatase-1 (PP-1). In this study, we investigated the regulation of DARPP-32 phosphorylation at its other sites, Thr75 [cyclin-dependent kinase-5 (Cdk5) site], Ser97 (CK2 site), and Ser130 (CK1 site), that serve to modulate Thr34 phosphorylation and dephosphorylation. In neostriatal slices, nicotine (100 microM) increased phosphorylation of DARPP-32 at Ser97 and Ser130 at an early time point (30 s) and decreased phosphorylation of DARPP-32 at Thr75 at a late time point (3 min). The increase in Ser97 and Ser130 phosphorylation was mediated through the release of dopamine via activation of alpha4beta2(*) nAChRs and alpha7 nAChRs and the subsequent activation of dopamine D1 and D2 receptors. The decrease in Thr75 phosphorylation was mediated through the release of dopamine via activation of alpha4beta2(*) nAChRs and the subsequent activation of dopamine D1 receptors. These various actions of nicotine on modulatory sites of phosphorylation would be predicted to result in a synergistic increase in the state of phosphorylation of DARPP-32 at Thr34 and thus would contribute to increased dopamine D1 receptor/DARPP-32 Thr34/PP-1 signaling.

Protective actions of various local anesthetics against the membrane dysfunction produced by in vitro ischemia in rat hippocampal CA1 neurons

Local anesthetics block not only the Na(+) but also the K(+) and Ca(2+) channels in the mammalian neurons. It is well known that lidocaine has neuroprotective actions against the ischemic insult of neurons in the central nervous system. In order to elucidate how other local anesthetics as well as lidocaine show the neuroprotective effects against in vitro ischemic insult, intracellular recordings were made from CA1 pyramidal neurons in rat hippocampal slices. Superfusion with the medium deprived of oxygen and glucose (in vitro ischemia) produced a rapid depolarization after 5 min of exposure. When the normal medium was immediately reintroduced after the rapid depolarization, the membrane depolarized further (persistent depolarization), the neurons showed no functional recovery. Pretreatment with tetracaine, bupivacaine, procaine, lidocaine, mepivacaine, or dibucaine (10 or 300 microM) prolonged the latency of the rapid depolarization, and most of the drugs partially restored the membrane potential toward the pre-exposure level after the reintroduction. Judging from the neuroprotective actions such as the prolongation and the potential recovery by these drugs, lidocaine, bupivacaine, and dibucaine are candidates for the therapeutic use against the ischemic insult. Suppression of the regenerative Na(+) conductance is somehow involved in the neuroprotective actions of local anesthetics.

Differential regulation of dopamine D1 and D2 signaling by nicotine in neostriatal neurons

Nicotine, acting on nicotinic acetylcholine receptors (nAChRs) expressed at pre-synaptic dopaminergic terminals, has been shown to stimulate the release of dopamine in the neostriatum. However, the molecular consequences of pre-synaptic nAChR activation in post-synaptic neostriatal neurons are not clearly understood. Here, we investigated the effect of nAChR activation on dopaminergic signaling in medium spiny neurons by measuring phosphorylated DARPP-32 (dopamine- and cAMP-regulated phosphoprotein of Mr 32 kDa) at Thr34 (the PKA-site) in mouse neostriatal slices. Nicotine produced dose-dependent responses, with a low concentration (1 microm) causing a sustained decrease in DARPP-32 Thr34 phosphorylation and a high concentration (100 microm) causing a transient increase in DARPP-32 Thr34 phosphorylation. Depending on the concentration of nicotine, either dopamine D2 or D1 receptor signaling was predominantly activated. Nicotine at a low concentration (1 microm) activated dopamine D2 receptor signaling in striatopallidal/indirect pathway neurons, likely by activating alpha4beta2* nAChRs at dopaminergic terminals. Nicotine at a high concentration (100 microm) activated dopamine D1 receptor signaling in striatonigral/direct pathway neurons, likely by activating (i) alpha4beta2* nAChRs at dopaminergic terminals and (ii) alpha7 nAChRs at glutamatergic terminals, which, by stimulating the release of glutamate, activated NMDA/AMPA receptors at dopaminergic terminals. The differential effects of low and high nicotine concentrations on D2- and D1-dependent signaling pathways in striatal neurons may contribute to dose-dependent actions of this drug of abuse.

A very rare anatomic variation of the right ventricular branch: right ventricular descending branch from the anterior interventricular branch

The anterior interventricular branch of the left coronary artery has the most constant distribution in the human heart and rarely gives off right ventricular branches. Here we report a case with a right ventricular branch which diverged from the anterior interventricular branch and descended on the anterior right ventricular wall parallel to the anterior interventricular sulcus; we termed it the "right ventricular descending branch." This artery gave a collateral artery to the occluded anterior interventricular branch at the apex, and had prevented anterior myocardial infarction. The right ventricular descending branch should be precisely identified in order to perform successful myocardial revascularization procedures such as coronary artery bypass grafting and percutaneous coronary intervention, especially in a patient with anterior interventricular branch occlusion.

[Emergency coronary artery bypass grafting for acute coronary syndrome with preoperative intraaortic balloon pumping; comparative surgical outcome and long-term results]

With recent technical improvements in catheter interventional therapy, percutaneous coronary intervention (PCI) has now become the treatment of first choice for acute coronary syndrome (ACS). The objective of the present study was to evaluate critically the timing of coronary artery bypass grafting (CABG) for severe ACS with preoperative intraaortic balloon pumping (IABP). Since 1994, a total of 70 patients have gone emergency or urgent CABG for ACS. Of 70 patients, 50 patients required preoperative IABP. There were 22 patients (17 men, 5 women) with acute myocardial infarction (AMI), with a mean age of 67.7 years, and 28 patients (19 men, 9 women) with unstable angina pectoris (UAP), with a mean age of 69.2 years. There was a significant difference, between AMI and UAP, in the prevalence of emergency operation (95.5% vs 25.0%), in preoperative cardiogenic shock (81.8% vs 17.9%), in the level of preoperative CPK-MB (196.7 IU/l vs 2.0 IU/l) and in preoperative ejection fraction (41.8% vs 47.3%). Two patients in AMI required percutaneous cardiopulmonary support (PCPS). Thirteen patients in AMI and 22 patients in UAP presented left main trunk (LMT) disease. Of the 13 LMT patients in AMI, 4 patients were AMI due to acute occlusion in the LMT. The AMI patients received 2.45 distal anastomoses on average, while the UAP patients 3.14 distal anastomoses (p = 0.019). Excluding the mean number of distal anastomoses, there was no difference in the intraoperative technical factors, such as aortic cross clamping duration, cardiopulmonary bypass duration, rate of complete revascularization, between AMI and UAP. There were postoperative significant differences in low cardiac output syndrome (LOS) [45.6% in AMI vs 3.6% in UAP] and in prolongation of mechanical ventilation (59.1% in AMI vs 14.3% in UAP). The hospital mortality was 9.1% (2/22) in AMI, and 3.6% (1/28) in UAP, with no significant difference. Of these 3 patients, 1 patient died from perioperative cerebrovascular accident (CVA), another from LOS, and the other from postoperative mesenteric ischemia, with an overall mortality of 6.0% (3/50). The overall patency rate of the grafts was 100% in AMI and 96.6% in UAP. The 5-year-survival rate excluding in-hospital death was 72.5% in AMI, and 89.6% in UAP. The 5-year-cardiac event-free rate was 77% in AMI and 89.4% in UAP. The overall survival rate, and cardiac event-free rate, at 5 years was 80.8%, and 83.8%, respectively. In conclusion, for ACS cases, especially UAP cases of LMT, in which symptoms, findings of ischemia and hemodynamics are stabilized by medical intervention including IABP; emergency surgery could be avoided immediately after coronary angiography. Recovery in the ischemic myocardium is intended by IABP, and urgent surgery should be performed after sufficient and precise preoperative examinations. An improvement not only in the perioperative but also long-term results can be expected by performing complete revascularizations.