Helicobacter pylori infection is identified as a cardiovascular risk factor in Central Africans

Benjamin Longo-Mbenza,1 Jacqueline Nkondi Nsenga,2 Etienne Mokondjimobe,3 Thierry Gombet,3 Itoua Ngaporo Assori,3 Jean Rosaire Ibara,3 Bertrand Ellenga-Mbolla,3 Dieudonné Ngoma Vangu,4 Simon Mbungu Fuele41Faculty of Health Sciences, Walter Sisulu University, Mthatha, South Africa; 2Division of Gastroenterology, University of Kinshasa, Kinshasa, Democratic Republic of the Congo; 3Faculty of Health Sciences, University of Marien Ngouabi, Brazzaville, Democratic Republic of the Congo; 4Biostatistics Unit, Lomo Medical Center, Limete, Kinshasa, Democratic Republic of the CongoBackground: Helicobacter pylori is now incriminated in the pathogenesis of atherosclerosis.Objective: To examine the importance of H. pylori infection as a cardiovascular disease (CVD) risk factor.Methods: Two hundred five patients (128 with H. pylori infection [HP-seropositive] and 77 without) had a baseline assessment for other potential CVD risk factors and were followed prospectively for 10 years (1999–2008). They were assessed on a monthly basis for the outcomes of carotid plaque, angina pectoris, myocardial infarction, and stroke. In the HP-seropositive group, male sex and quartile 4 for IgG anti-H. pylori antibodies (anti-HP Ab) were correlated with traditional CVD risk factors, stroke, myocardial infarction, and angina pectoris.Results: At the baseline assessment, the levels of carotid intima-media thickness, blood fibrinogen, total cholesterol, fasting plasma glucose, and uric acid were higher in H. pylori-infected patients than in the uninfected group. Serum HDL-cholesterol was significantly lower in the HP-seropositive group. Men had higher levels of IgG anti-HP Ab, waist circumference, blood pressure, uric acid, and total cholesterol than women. Within the HP-seropositive group, individuals in quartile 4 for IgG anti-HP Ab had higher rates of elevated fibrinogen, diabetes mellitus, low high-density lipoprotein cholesterol, arterial hypertension, and high total cholesterol than those in quartile 1. After adjusting for traditional CVD risk factors, H. pylori infection was the only independent predictor of incident carotid plaque (multivariate odds ratio [OR] = 2.3, 95% confidence interval [CI]: 1.2–7.2; P < 0.0001) and incident acute stroke (multivariate OR = 3.6, 95% CI: 1.4–8.2; P < 0.0001). Within the HP-seropositive group and after adjusting for traditional CVD risk factors, male sex was the only independent predictor of incident angina pectoris (multivariate OR = 3.5, 95% CI: 1.6–16; P < 0.0001), incident acute stroke (multivariate OR = 3.2, 95% CI: 1.4–28; P < 0.0001), and acute myocardial infarction (multivariate OR = 7.2, 95% CI: 3.1–18; P < 0.0001).Conclusion: Our study provides evidence for an association among known CVD risk factors, carotid plaque, stroke, and H. pylori infection. Among infected individuals, there is a significant association among severity of HP-seropositivity, male sex, and CVD. The eradication of H. pylori infection may therefore reduce the emerging burden of CVD in Africa.Keywords: Helicobacter pylori, stroke, myocardial infarction, cardiovascular disease, carotid plaque, African

The relevance of temporal cues in a fish sound: a first experimental investigation using modified signals in cichlids

International audiencePlayback experiments have been a useful tool for studying the function of sounds and the relevance of different sound characteristics in signal recognition in many different species of vertebrates. However, successful playback experiments in sound-producing fish remain rare, and few studies have investigated the role of particular sound features in the encoding of information. In this study, we set-up an apparatus in order to test the relevance of acoustic signals in males of the cichlid Metriaclima zebra. We found that territorial males responded more to playbacks by increasing their territorial activity and approaching the loudspeaker during and after playbacks. If sounds are used to indicate the presence of a competitor, we modified two sound characteristics, that is, the pulse period and the number of pulses, in order to investigate whether the observed behavioural response was modulated by the temporal structure of sounds recorded during aggressive interactions. Modified sounds yielded little or no effect on the behavioural response they elicited in territorial males, suggesting a high tolerance for variations in pulse period and number of pulses. The biological function of sounds in M. zebra and the lack of responsiveness to our temporal modifications are discussed

Sounds of shallow water fishes pitch within the quiet window of the habitat ambient noise

The habitat ambient noise may exert an important selective pressure on frequencies used in acoustic communication by animals. A previous study demonstrated the presence of a match between the low-frequency quiet region of the stream ambient noise (termed 'quiet window') and the main frequencies used for sound production and hearing by two stream gobies (Padogobius bonelli, Gobius nigricans). The present study examines the spectral features of ambient noise in very shallow freshwater, brackish and marine habitats and correlates them to the range of dominant frequencies of sounds used by nine species of Mediterranean gobies reproducing in these environments. Ambient noise spectra of these habitats featured a low-frequency quiet window centered at 100 Hz (stream, sandy/rocky sea shore), or at 200 Hz (spring, brackish lagoon). The analysis of the ambient noise/sound spectrum relationships showed the sound frequencies matched the frequency band of the quiet window in the ambient noise typical of their own habitat. Analogous ambient noise/sound frequency relationships were observed in other shallow-water teleosts living in similar underwater environments. Conclusions may be relevant to the understanding of evolution of fish acoustic communication and hearing