NMDA receptors in nucleus tractus solitarii are linked to soluble guanylate cyclase

We sought to test the hypothesis that cardiovascular responses to activation of ionotropic, but not metabotropic, glutamate receptors in the nucleus tractus solitarii (NTS) depend on soluble guanylate cyclase (sGC) and that inhibition of sGC would attenuate baroreflex responses to changes in arterial pressure. In adult male Sprague-Dawley rats anesthetized with chloralose, the ionotropic receptor agonists N-methyl-d-aspartate (NMDA) and dl-alpha-amino-3-hydroxy-5-methylisoxazole-propionic acid (AMPA) and the metabotropic receptor agonist trans-dl-amino-1,3-cyclopentane-dicarboxylic acid (ACPD) were microinjected into the NTS before and after microinjection of sGC inhibitors at the same site. Inhibition of sGC produced significant dose-dependent attenuation of cardiovascular responses to NMDA but did not alter responses produced by injection of AMPA or ACPD. Bilateral inhibition of sGC did not alter arterial pressure, nor did it attenuate baroreflex responses to pharmacologically induced changes in arterial pressure. This study links sGC with NMDA, but not AMPA or metabotropic, receptors in cardiovascular signal transduction through NTS.     

Time Trends in Incidence and Mortality of Acute Myocardial Infarction,and All-Cause Mortality following a Cardiovascular Prevention Program in Sweden

Background

In 1988, a cardiovascular prevention program which combined an individual and a population-based strategy was launched within primary health-care in Sollentuna, a municipality in Stockholm County. The aim of this study was to investigate time trends in the incidence of and mortality from acute myocardial infarction and all-cause mortality in Sollentuna compared with the rest of Stockholm County during a period of two decades following the implementation of a cardiovascular prevention program.

Materials and Methods

The average population in Sollentuna was 56,589 (49% men) and in Stockholm County (Sollentuna included) 1,795,504 (49% men) during the study period of 1987–2010. Cases of hospitalized acute myocardial infarction and death were obtained for the population of Sollentuna and the rest of Stockholm County using national registries of hospital discharges and deaths. Acute myocardial infarction incidence and mortality were estimated using the average population of Sollentuna and Stockholm in 1987–2010.

Results

During the observation period, the incidence of acute myocardial infarction decreased more in Sollentuna compared with the rest of Stockholm County in women (-22% vs. -7%; for difference in slope <0.05). There was a trend towards a greater decline in Sollentuna compared to the rest of Stockholm County in the incidence of acute myocardial infarction (in men), acute myocardial mortality, and all-cause mortality but the differences were not significant.

Conclusion

During a period of steep decline in acute myocardial infarction incidence and mortality in Stockholm County the municipality of Sollentuna showed a stronger trend in women possibly compatible with favorable influence of a cardiovascular prevention program.

Trial Registration

ClinicalTrials.gov NCT02212145     

Proteomic analysis of Plasmodium in the mosquito: progress and pitfalls

Here we discuss proteomic analyses of whole cell preparations of the mosquito stages of malaria parasite development (i.e. gametocytes, microgamete, ookinete, oocyst and sporozoite) of Plasmodium berghei. We also include critiques of the proteomes of two cell fractions from the purified ookinete, namely the micronemes and cell surface. Whereas we summarise key biological interpretations of the data, we also try to identify key methodological constraints we have met, only some of which we were able to resolve. Recognising the need to translate the potential of current genome sequencing into functional understanding, we report our efforts to develop more powerful combinations of methods for the in silico prediction of protein function and location. We have applied this analysis to the proteome of the male gamete, a cell whose very simple structural organisation facilitated interpretation of data. Some of the in silico predictions made have now been supported by ongoing protein tagging and genetic knockout studies. We hope this discussion may assist future studies.     

Impact of social support intensity on walking in the severely obese: a randomized clinical trial

Objective: There are few established methods for promoting physical activity (PA) in the severely obese. Because social support is a potential method for promoting PA, we compared mean steps/day during 18 weeks in severely obese outpatients receiving either standard support (SS) or added support (AS). Methods and Procedures: Eighty severely obese outpatients from an obesity clinic were invited; 66 provided written consent, 55 were randomized, and 42 were included in final analyses (9 men, 33 women; age 44.4 ± 13.1 years; BMI 41.9 ± 5.5 kg/m²). All participants received a pedometer and a walking promotion booklet. In addition to SS, the AS group received ten 2‐h group counseling sessions aimed at increasing weekly accumulated steps, every second week during the study. Each participant was asked to complete a 7‐day walking diary every second week (10 observations). Results: Baseline steps/day was 6,912 for the AS group and 5,311 for the SS group (P = 0.023). Data at 18 weeks showed that the AS group recorded 10,136 steps/day and the SS group 6,118 steps/day (P = 0.024). There was no allocation × time interaction (P = 0.46). During the follow‐up period as a whole, the AS group recorded 1,794 more steps/day than the SS group (P = 0.0074). Discussion: The AS group recorded more steps/day than the SS group, reaching a mean level of ～10,000 steps/day. However, the nonsignificant interaction between allocation × time suggests that this difference was present already at baseline and did not increase during follow‐up.     

A Plasmodium falciparum Strain Expressing GFP throughout the Parasite's Life-Cycle

The human malaria parasite Plasmodium falciparum is responsible for the majority of malaria-related deaths. Tools allowing the study of the basic biology of P. falciparum throughout the life cycle are critical to the development of new strategies to target the parasite within both human and mosquito hosts. We here present 3D7HT-GFP, a strain of P. falciparum constitutively expressing the Green Fluorescent Protein (GFP) throughout the life cycle, which has retained its capacity to complete sporogonic development. The GFP expressing cassette was inserted in the Pf47 locus. Using this transgenic strain, parasite tracking and population dynamics studies in mosquito stages and exo-erythrocytic schizogony is greatly facilitated. The development of 3D7HT-GFP will permit a deeper understanding of the biology of parasite-host vector interactions, and facilitate the development of high-throughput malaria transmission assays and thus aid development of new intervention strategies against both parasite and mosquito.     

Content and In Vitro Release of Endogenous Amino Acids in the Area of the Nucleus of the Solitary Tract of the Rat

We sought to identify amino acid neurotransmitter candidates within the nucleus of the solitary tract in rats. Twenty endogenous amino acids were quantified by reverse-phase HPLC with fluorescence detection (30-fmol limit). Micropunches (1 mm) of the intermediate area of the solitary nucleus were prepared, and the amino acid content determined. Of all the components measured, the putative transmitters Glu, Gly, gamma-aminobutyric acid, taurine, Asp, and Ala appeared in greatest concentrations. Bilateral micropunches superfused in vitro with buffered medium containing 56 mM potassium released Glu, gamma-aminobutyric acid, and Gly in a significant manner (p less than 0.05) compared with basal levels. With Glu, 78% was calcium-dependent and, therefore, presumably from nerve endings; 99% of gamma-aminobutyric acid and 42% of Gly were dependent on calcium. After removal of the nodose ganglion, a bilateral decrease in the calcium-dependent release of Glu and gamma-aminobutyric acid, but not Gly, was observed; decreases were significant ipsilateral to the site of ablation. We conclude that (a) Glu is a transmitter of primary afferents in the nucleus of the solitary tract; (b) glutamatergic afferents may interact with gamma-aminobutyric acid system(s) in this region; (c) Gly also may participate in the mediation and/or modulation of cardiovascular or other visceral reflexes; and (d) amino acid neurotransmission may play an integral role in the neurogenic control of arterial pressure.     

Cationic Lipid-Formulated DNA Vaccine against Hepatitis B Virus: Immunogenicity of MIDGE-Th1 Vectors Encoding Small and Large Surface Antigen in Comparison to a Licensed Protein Vaccine

Currently marketed vaccines against hepatitis B virus (HBV) based on the small (S) hepatitis B surface antigen (HBsAg) fail to induce a protective immune response in about 10% of vaccinees. DNA vaccination and the inclusion of PreS1 and PreS2 domains of HBsAg have been reported to represent feasible strategies to improve the efficacy of HBV vaccines. Here, we evaluated the immunogenicity of SAINT-18-formulated MIDGE-Th1 vectors encoding the S or the large (L) protein of HBsAg in mice and pigs. In both animal models, vectors encoding the secretion-competent S protein induced stronger humoral responses than vectors encoding the L protein, which was shown to be retained mainly intracellularly despite the presence of a heterologous secretion signal. In pigs, SAINT-18-formulated MIDGE-Th1 vectors encoding the S protein elicited an immune response of the same magnitude as the licensed protein vaccine Engerix-B, with S protein-specific antibody levels significantly higher than those considered protective in humans, and lasting for at least six months after the third immunization. Thus, our results provide not only the proof of concept for the SAINT-18-formulated MIDGE-Th1 vector approach but also confirm that with a cationic-lipid formulation, a DNA vaccine at a relatively low dose can elicit an immune response similar to a human dose of an aluminum hydroxide-adjuvanted protein vaccine in large animals.     

Vital functions of the malarial ookinete protein, CTRP, reside in the A domains

The transformation of malaria ookinetes into oocysts occurs in the mosquito midgut and is a major bottleneck for parasite transmission. The secreted ookinete surface protein, circumsporozoite- and thrombospondin-related adhesive protein (TRAP)-related protein (CTRP), is essential for this transition and hence constitutes a potential target for malaria transmission blockade. CTRP is a modular multidomain protein containing six tandem von Willebrand factor A-like (A) domains and seven tandem thrombospondin type I repeat-like (TS) domains. Here we present, to our knowledge, the first structure-function analysis of CTRP using genetically modified Plasmodium berghei parasites expressing mutant versions of the ctrp gene. Our data show that the A domains of CTRP are critical for ookinete gliding motility and oocyst formation whilst, unexpectedly, its TS domains are fully redundant. These results may have important implications for the design of CTRP-based transmission blocking strategies.