Activation of Metabotropic Glutamate Receptors Inhibits Synapsin I Phosphorylation in Visceral Sensory Neurons

Activation of glutamate metabotropic receptors (mGluRs) in nodose ganglia neurons has previously been shown to inhibit voltage-gated Ca⁺⁺ currents and synaptic vesicle exocytosis. The present study describes the effects of mGluRs on depolarization-induced phosphorylation of the synaptic-vesicle-associated protein synapsin I. Depolarization of cultured nodose ganglia neurons with 60 mm KCl resulted in an increase in synapsin I phosphorylation. Application of mGluR agonists 1-aminocyclopentane-1s-3r-dicarboxylic acid (t-ACPD) and L(+)-2-Amino-4-phosphonobutyric acid (L-AP4) either in combination or independently inhibited the depolarization induced phosphorylation of synapsin I. Application of the mGluR antagonist (RS)-α-Methyl-4-carboxyphenylglycine (MCPG) blocked t-ACPD-induced inhibition of synapsin phosphorylation but not the effects of L-AP4. In addition, application of either t-ACPD or L-AP4 in the absence of KCl induced depolarization had no effect on resting synapsin I phosphorylation. RT-PCR analysis of mGluR subtypes in these nodose ganglia neurons revealed that these cells only express group III mGluR subtypes 7 and 8. These results suggest that activation of mGluRs modulates depolarization-induced synapsin I phosphorylation via activation of mGluR7 and/or mGluR8 and that this process may be involved in mGluR inhibition of synaptic vesicle exocytosis in visceral sensory neurons of the nodose ganglia. Received 28 June 2000/Revised: 11 September 2000     

Detection and Characterization of Clade 1 Reassortant H5N1 Viruses Isolated from Human Cases in Vietnam during 2013

Highly pathogenic avian influenza (HPAI) H5N1 is endemic in Vietnamese poultry and has caused sporadic human infection in Vietnam since 2003. Human infections with HPAI H5N1 are of concern due to a high mortality rate and the potential for the emergence of pandemic viruses with sustained human-to-human transmission. Viruses isolated from humans in southern Vietnam have been classified as clade 1 with a single genome constellation (VN3) since their earliest detection in 2003. This is consistent with detection of this clade/genotype in poultry viruses endemic to the Mekong River Delta and surrounding regions. Comparison of H5N1 viruses detected in humans from southern Vietnamese provinces during 2012 and 2013 revealed the emergence of a 2013 reassortant virus with clade 1.1.2 hemagglutinin (HA) and neuraminidase (NA) surface protein genes but internal genes derived from clade 2.3.2.1a viruses (A/Hubei/1/2010-like; VN12). Closer analysis revealed mutations in multiple genes of this novel genotype (referred to as VN49) previously associated with increased virulence in animal models and other markers of adaptation to mammalian hosts. Despite the changes identified between the 2012 and 2013 genotypes analyzed, their virulence in a ferret model was similar. Antigenically, the 2013 viruses were less cross-reactive with ferret antiserum produced to the clade 1 progenitor virus, A/Vietnam/1203/2004, but reacted with antiserum produced against a new clade 1.1.2 WHO candidate vaccine virus (A/Cambodia/W0526301/2012) with comparable hemagglutination inhibition titers as the homologous antigen. Together, these results indicate changes to both surface and internal protein genes of H5N1 viruses circulating in southern Vietnam compared to 2012 and earlier viruses.     

SPEAR Trial: Smartphone Pediatric ElectrocARdiogram Trial

Objectives

Smartphone-enabled ECG devices have the potential to improve patient care by enabling remote ECG assessment of patients with potential and diagnosed arrhythmias. This prospective study aimed to assess the usefulness of pediatric ECG tracings generated by the AliveCor device (Oklahoma City, OK) and to assess user satisfaction.

Study Design

Enrolled pediatric patients with documented paroxysmal arrhythmia used the AliveCor device over a yearlong study period. Pediatric electrophysiologists reviewed all transmitted ECG tracings. Patient completed surveys were analyzed to assess user satisfaction.

Results

35 patients were enrolled with the following diagnoses: supraventricular tachycardia (SVT, 57%), atrial fibrillation (AF, 11%), ectopic atrial tachycardia (EAT, 6%), atrial tachycardia (AT, 3%), and ventricular tachycardia (VT, 23%). A total of 238 tracings were received from 20 patients, 96% of which were of diagnostic quality for sinus rhythm, sinus tachycardia, SVT, and AF. 126 patient satisfaction surveys (64% from parents) were completed. 98% of the survey responses indicated that it was easy to obtain tracings, 93% found it easy to transmit the tracings, 98% showed added comfort in managing arrhythmia by having the device, and 93% showed interest in continued use of the device after the study period ended.

Conclusions

Smartphone-enabled ECG devices can generate tracings of diagnostic quality in children. User satisfaction was extremely positive. Use of the device to manage certain patients with AF and SVT showcases the future role of remote ECGs in the successful outpatient management of arrhythmias in children by potentially reducing Emergency Department visits and healthcare costs.     

Long Withdrawal of Methylphenidate Induces a Differential Response of the Dopaminergic System and Increases Sensitivity to Cocaine in the Prefrontal Cortex of Spontaneously Hypertensive Rats

Methylphenidate (MPD) is one of the most prescribed drugs for alleviating the symptoms of Attention Deficit/Hyperactivity Disorder (ADHD). However, changes in the molecular mechanisms related to MPD withdrawal and susceptibility to consumption of other psychostimulants in normal individuals or individuals with ADHD phenotype are not completely understood. The aims of the present study were: (i) to characterize the molecular differences in the prefrontal dopaminergic system of SHR and Wistar strains, (ii) to establish the neurochemical consequences of short- (24 hours) and long-term (10 days) MPD withdrawal after a subchronic treatment (30 days) with Ritalin® (Methylphenidate Hydrochloride; 2.5 mg/kg orally), (iii) to investigate the dopaminergic synaptic functionality after a cocaine challenge in adult MPD-withdrawn SHR and Wistar rats. Our results indicate that SHR rats present reduced [³H]-Dopamine uptake and cAMP accumulation in the prefrontal cortex (PFC) and are not responsive to dopaminergic stimuli in when compared to Wistar rats. After a 24-hour withdrawal of MPD, SHR did not present any alterations in [³H]-Dopamine Uptake, [³H]-SCH 23390 binding and cAMP production; nonetheless, after a 10-day MPD withdrawal, the results showed a significant increase of [³H]-Dopamine uptake, of the quantity of [³H]-SCH 23390 binding sites and of cAMP levels in these animals. Finally, SHR that underwent a 10-day MPD withdrawal and were challenged with cocaine (10 mg/kg i.p.) presented reduced [³H]-Dopamine uptake and increased cAMP production. Wistar rats were affected by the 10-day withdrawal of MPD in [³H]-dopamine uptake but not in cAMP accumulation; in addition, cocaine was unable to induce significant modifications in [³H]-dopamine uptake and in cAMP levels after the 10-day withdrawal of MPD. These results indicate a mechanism that could explain the high comorbidity between ADHD adolescent patients under methylphenidate treatment and substance abuse in adult life.     

Physical Activity in Vietnam: Estimates and Measurement Issues

IntroductionOur aims were to provide the first national estimates of physical activity (PA) for Vietnam, and to investigate issues affecting their accuracy.MethodsMeasurements were made using the Global Physical Activity Questionnaire (GPAQ) on a nationally-representative sample of 14706 participants (46.5% males, response 64.1%) aged 25−64 years selected by multi-stage stratified cluster sampling.ResultsApproximately 20% of Vietnamese people had no measureable PA during a typical week, but 72.9% (men) and 69.1% (women) met WHO recommendations for PA by adults for their age. On average, 52.0 (men) and 28.0 (women) Metabolic Equivalent Task (MET)-hours/week (largely from work activities) were reported. Work and total PA were higher in rural areas and varied by season. Less than 2% of respondents provided incomplete information, but an additional one-in-six provided unrealistically high values of PA. Those responsible for reporting errors included persons from rural areas and all those with unstable work patterns. Box-Cox transformation (with an appropriate constant added) was the most successful method of reducing the influence of large values, but energy-scaled values were most strongly associated with pathophysiological outcomes.ConclusionsAround seven-in-ten Vietnamese people aged 25–64 years met WHO recommendations for total PA, which was mainly from work activities and higher in rural areas. Nearly all respondents were able to report their activity using the GPAQ, but with some exaggerated values and seasonal variation in reporting. Data transformation provided plausible summary values, but energy-scaling fared best in association analyses.     

Rapid dissection of a complex phenotype through genomic-scale mapping of fitness altering genes

The understanding and engineering of complex phenotypes is a critical issue in biotechnology. Conventional approaches for engineering such phenotypes are often resource intensive, marginally effective, and unable to generate the level of biological understanding desired. Here, we report a new approach for rapidly dissecting a complex phenotype that is based upon the combination of genome-scale growth phenotype data, precisely targeted growth selections, and informatic strategies for abstracting and summarizing data onto coherent biological processes. We measured at high resolution (125 NT) and for the entire genome the effect of increased gene copy number on overall biological fitness corresponding to the expression of a complex phenotype (tolerance to 3-hydroxypropionic acid (3-HP) in Escherichia coli). Genetic level fitness data were then mapped according to various definitions of gene–gene interaction in order to generate network-level fitness data. When metabolic pathways were used to define interactions, we observed that genes within the chorismate and threonine super-pathways were disproportionately enriched throughout selections for 3-HP tolerance. Biochemical and genetic studies demonstrated that alleviation of inhibition of either of these super-pathways was sufficient to mitigate 3-HP toxicity. These data enabled the design of combinatorial modifications that almost completely offset 3-HP toxicity in minimal medium resulting in a 20 g/L and 25-fold increase in tolerance and specific growth, respectively.     

Genetic introgression between an introduced babbler, the Chinese hwamei Leucodioptron c. canorum, and the endemic Taiwan hwamei L. taewanus: a multiple marker systems analysis

Identification of interspecific hybrids is often a subject of primary concern in the development of conservation strategies. Here we performed a genetic analysis combining mitochondrial DNA (mtDNA), microsatellites and single nucleotide polymorphic sites (SNPs) to assay the level of hybridization and introgression between an introduced babbler, Chinese hwamei Leucodioptron canorus, and its close relative, the endemic Taiwan hwamei L. taewanus in Taiwan. Fifty‐five Chinese hwameis from the Asian mainland and 69 Taiwan hwameis, including nine morphological hybrids, were sampled and analyzed. Evidences of mitochondrial introgression were found in three hybrids and one Taiwan hwamei. Five unlinked interspecific SNPs were identified at nine anonymous nuclear loci with interspecific differentiation (total Fst=0.77) that was much higher than that at seven highly polymorphic microsatellite loci combined (total Fst=0.1). Bayesian cluster analysis based on five interspecific SNP loci and two highly differentiated microsatellite loci (Fst>0.08) suggested that twelve individuals sampled in Taiwan were likely F2 or backcross hybrids, among which eight were morphological intermediates. A total of 20.3% (14/69) individuals sampled in Taiwan were suggested to be hybrids, suggesting that fitness reduction in hybrids might be negligible. These results imply that without an effective management strategy, the entire Taiwan hwamei population could easily become an admixed with Chinese hwamei and loose its evolutionary integrity. To reduce introgressive hybridization, illegal trade of Chinese hwamei should be strictly regulated and only the expensive male Chinese hwameis should be legally imported to minimize the chance for Chinese hwameis being released into the field. In our study we also found interspecific SNP markers to outperform microsatellite loci in detecting hybridization and introgression between two closely related species, which may be ascribed to the lower level of homoplasy of SNP loci.     

The neutral lipid composition present in the digestive vacuole of Plasmodium falciparum concentrates heme and mediates β-hematin formation with an unusually low activation energy

In eukaryotic cells, neutral lipids serve as major energy storage molecules; however, in Plasmodium falciparum, a parasite responsible for causing malaria in humans, neutral lipids may have other functions during the intraerythrocytic stage of the parasite life cycle. Specifically, experimental data suggest that neutral lipid structures behave as a catalyst for the crystallization of hemozoin, a detoxification byproduct of several blood-feeding organisms, including malaria parasites. Synthetic neutral lipid droplets (SNLDs) were produced by depositing a lipid blend solution comprised of mono- and diglycerides onto an aqueous surface. These lipid droplets are able to mediate the production of brown pigments that are morphologically and chemically identical to hemozoin. The partitioning of heme into these SNLDs was examined by employing Nile Red, a lipid specific dye. Soluble ferriprotoporphyrin IX was observed to spontaneously localize to the lipid droplets, partitioning in a pH-dependent manner with an estimated log P of 2.6. Interestingly, the pH profile of heme partitioning closely resembles that of β-hematin formation. Differential scanning calorimetry and kinetic studies demonstrated that the SNLDs provide a unique environment that promotes hemozoin formation. SNLD-mediated formation of the malaria pigment displayed an activation energy barrier lower than those of individual lipid components. In particular, lipid droplets composed of diglycerides displayed activation barriers lower than those composed of monoglycerides. This difference was attributed to the greater fluidity of these lipids. In conjunction with the known pattern of lipid body proliferation, it is suggested that neutral lipid structures within the digestive vacuole not only are the location of in vivo hemozoin formation but are also essential for the survival of the parasite by functioning as a kinetically competent and site specific mediator for heme detoxification.