Concurrent outbreaks of dengue, chikungunya and Zika virus infections - an unprecedented epidemic wave of mosquito-borne viruses in the Pacific 2012-2014

Since January 2012, the Pacific Region has experienced 28 new documented outbreaks and circulation of dengue, chikungunya and Zika virus. These mosquito-borne disease epidemics seem to become more frequent and diverse, and it is likely that this is only the early stages of a wave that will continue for several years. Improved surveillance and response measures are needed to mitigate the already heavy burden on island health systems and limit further spread to other parts of the world.

Unmasked Brugada pattern by ajmaline challenge in patients with myotonic dystrophy type 1

BACKGROUND

Myotonic dystrophy type 1 (DM1) generates missplicing of the SCN5A gene, encoding the cardiac sodium channel (Nav 1.5). Brugada syndrome, which partly results from Nav 1.5 dysfunction and causes increased VF occurrence, can be unmasked by ajmaline. We aimed to investigate the response to ajmaline challenge in DM1 patients and its potential impact on their sudden cardiac death risk stratification.

METHODS

Among 36 adult DM1 patients referred to our institution, electrophysiological study and ajmaline challenge were performed in 12 patients fulfilling the following criteria: (1) PR interval >200 ms or QRS duration >100 ms; (2) absence of complete left bundle branch block; (3) absence of permanent ventricular pacing; (4) absence of implantable cardioverter-defibrillator (ICD); (5) preserved left-ventricular ejection fraction >50%; and (6) absence of severe muscular impairment. Of note, DM1 patients with ajmaline-induced Brugada pattern (BrP) were screened for SCN5A.

RESULTS

In all the 12 patients studied, the HV interval was <70 ms. A BrP was unmasked in three patients but none carried an SCN5A mutation. Ajmaline-induced sustained ventricular tachycardia occurred in one patient with BrP, who finally received an ICD. The other patients did not present any cardiac event during the entire follow-up (15 ± 4 months).

CONCLUSION

Our study is the first to describe a high prevalence of ajmaline-induced BrP in DM1 patients. The indications, the safety, and the implications of ajmaline challenge in this particular setting need to be determined by larger prospective studies.

Can we identify response markers to antihypertensive drugs? First results from the IDEAL Trial

Current antihypertensive strategies do not take into account that individual characteristics may influence the magnitude of blood pressure (BP) reduction. Guidelines promote trial-and-error approaches with many different drugs. We conducted the Identification of the Determinants of the Efficacy of Arterial blood pressure Lowering drugs (IDEAL) Trial to identify factors associated with BP responses to perindopril and indapamide. IDEAL was a cross-over, double-blind, placebo-controlled trial, involving four 4-week periods: indapamide, perindopril and two placebo. Eligible patients were untreated, hypertensive and aged 25-70 years. The main outcome was systolic BP (SBP) response to drugs. The 112 participants with good compliance had a mean age of 52. One in every three participants was a woman. In middle-aged women, the SBP reduction from drugs was -11.5 mm Hg (indapamide) and -8.3 mm Hg (perindopril). In men, the response was significantly smaller: -4.8 mm Hg (indapamide) and -4.3 (perindopril) (P for sex differences 0.001 and 0.015, respectively). SBP response to perindopril decreased by 2 mm Hg every 10 years of age in both sexes (P=0.01). The response to indapamide increased by 3 mm Hg every 10 years of age gradient in women (P=0.02). Age and sex were important determinants of BP response for antihypertensive drugs in the IDEAL population. This should be taken into account when choosing drugs a priori.

The β1-subunit of Na(v)1.5 cardiac sodium channel is required for a dominant negative effect through α-α interaction

Brugada syndrome (BrS) is an inherited autosomal dominant cardiac channelopathy. Several mutations on the cardiac sodium channel Na_v1.5 which are responsible for BrS lead to misfolded proteins that do not traffic properly to the plasma membrane. In order to mimic patient heterozygosity, a trafficking defective mutant, R1432G was co-expressed with Wild Type (WT) Na_v1.5 channels in HEK293T cells. This mutant significantly decreased the membrane Na current density when it was co-transfected with the WT channel. This dominant negative effect did not result in altered biophysical properties of Na_v1.5 channels. Luminometric experiments revealed that the expression of mutant proteins induced a significant reduction in membrane expression of WT channels. Interestingly, we have found that the auxiliary Na channel β₁-subunit was essential for this dominant negative effect. Indeed, the absence of the β₁-subunit prevented the decrease in WT sodium current density and surface proteins associated with the dominant negative effect. Co-immunoprecipitation experiments demonstrated a physical interaction between Na channel α-subunits. This interaction occurred only when the β₁-subunit was present. Our findings reveal a new role for β₁-subunits in cardiac voltage-gated sodium channels by promoting α-α subunit interaction which can lead to a dominant negative effect when one of the α-subunits shows a trafficking defective mutation.

Molecular identification of Fasciola spp. (Digenea: Fasciolidae) in Egypt

A total of 134 Egyptian liver flukes were collected from different definitive hosts (cattle, sheep, and buffaloes) to identify them via the use of PCR-RFLP and sequence analysis of the first nuclear ribosomal internal transcribed spacer (ITS1). Specimens of F. hepatica from France, as well as F. gigantica from Cameroon were included in the study for comparison. PCR products of ITS1 were subjected for digestion by RsaI restriction enzyme and visualized on agarose gel. According to RFLP pattern, Egyptian flukes were allocated into two categories. The first was identical to that of French hepatica flukes to have a pattern of 360, 100, and 60 (bp) band size, whereas the second resembled to that of Cameroonian gigantica worms to have a profile of 360, 170, and 60 bp in size. Results of RFLP analysis were confirmed by sequence analysis of representative ITS1 amplicons. No hybrid forms were detected in the present study. Taken together, this study concluded that both species of Fasciola are present in Egypt, whereas the hybrid form may be not very common.

A distinct de novo expression of Nav1.5 sodium channels in human atrial fibroblasts differentiated into myofibroblasts

Fibroblasts play a major role in heart physiology. They are at the origin of the extracellular matrix renewal and production of various paracrine and autocrine factors. In pathological conditions, fibroblasts proliferate, migrate and differentiate into myofibroblasts leading to cardiac fibrosis. This differentiated status is associated with changes in expression profile leading to neo-expression of proteins such as ionic channels. The present study investigates further electrophysiological changes associated with fibroblast differentiation focusing on the activity of voltage-gated sodium channels in human atrial fibroblasts and myofibroblasts. Using the patch clamp technique we show that human atrial myofibroblasts display a fast inward voltage gated sodium current with a density of 13.28 ± 2.88 pA pF(-1) whereas no current was detectable in non-differentiated fibroblasts. Quantitative RT-PCR reveals a large amount of transcripts encoding the Na(v)1.5 α-subunit with a fourfold increased expression level in myofibroblasts when compared to fibroblasts. Accordingly, half of the current was blocked by 1 μm of tetrodotoxin and immunocytochemistry experiments reveal the presence of Na(v)1.5 proteins. Overall, this current exhibits similar biophysical characteristics to sodium currents found in cardiac myocytes except for the window current that is enlarged for potentials between -100 and -20 mV. Since fibrosis is one of the fundamental mechanisms implicated in atrial fibrillation, it is of great interest to investigate how this current could influence myofibroblast properties. Moreover, since several Na(v)1.5 mutations are related to cardiac pathologies, this study offers a new avenue on the fibroblasts involvement of these mutations.

Binder phenotype in mothers affected with autoimmune disorders

OBJECTIVE

To report four foetal cases of the Binder phenotype associated with maternal autoimmune disorders.

PATIENTS AND METHODS

In three mothers with autoimmune diseases, 2D and 3D ultrasonographic measurements were made on four foetuses with the Binder profile, and were compared with postnatal phenotypes.

RESULTS

The Binder phenotype can be detected in early pregnancy (14.5 WG). All foetuses had verticalized nasal bones and midfacial hypoplasia. Punctuate calcifications were found in almost all the cases. No specific maternal auto-antibody has been associated with foetal Binder phenotype.

CONCLUSION

Since the Binder phenotype can be diagnosed at ultrasound examination during pregnancy, it is important to establish the underlying cause so as to assess the foetal prognosis. This study stresses the importance of systematic checks for maternal autoimmune disease in cases of prenatally diagnosed Binder phenotypes.

Human impact on genetic diversity of Toxoplasma gondii: example of the anthropized environment from French Guiana

In French Guiana, severe cases of toxoplasmosis in immunocompetent patients are associated with atypical strains of Toxoplasma gondii linked to a wild neotropical rainforest cycle and a higher genetic diversity than usually observed for T. gondii isolates from anthropized environment. This raises the question of the impact of anthropization of the natural environment, on genetic diversity and on the population structure of T. gondii. However, few data are available on strains circulating in the anthropized areas from French Guiana. Seropositive animals originating mainly from anthropized sub-urban areas and punctually from wild environment in French Guiana were analyzed for T. gondii isolation and genotyping. Thirty-three strains were obtained by bioassay in mice and compared with 18 previously reported isolates chiefly originating from the Amazon rainforest. The genotyping analysis performed with 15 microsatellite markers located on 12 different chromosomes revealed a lower genetic diversity in the anthropized environment. Results were analyzed in terms of population structure by clustering methods, Neighbor-joining trees reconstruction based on genetic distances, F(ST,) Mantel's tests and linkage disequilibrium. They clearly showed a genetic differentiation between strains associated to the anthropized environment and those associated to the wild, but with some inbreeding between them. The majority of strains from the anthropized environment were clustered into additional lineages of T. gondii that are common in the Caribbean. In conclusion the two environmental populations "wild" and "anthropized" were genetically well differentiated. The anthropization of the environment seems to be accompanied with a decreased diversity of T. gondii associated with a greater structure of the populations. We detected potential interpenetration and genetic exchanges between these two environmental populations. As a higher pathogenicity in human of "wild" genotypes has been described, the interpenetration of both environments leads to hybridization between strains that may be at risk for human health.

[Obstacles to effective treatment of depression. A general practitioners' postal survey in the north-west region of France]

CONTEXT AND AIM

Depression is a quite common condition, and its treatment is mainly provided by General Practitioner (GP). It is already known that detection and treatment requires significant improvement. The well known and high consumption of antidepressant drugs in France, the highest of all other European countries, requires specific studies. The causes of this situation are not clear and seem to be numerous: Patient's demands, social claims; lack of initial and continuous medical education, bad GP demographic trends, and lack of them in rural areas; pharmaceutical company pressure; and organisation of the health care system. GP are the main medical actors of the primary care system in France. The aim of this study was to survey GP perceptions on secondary care services, seek the views and barriers to the provision of good services, and ask them about perceptions and solutions they could suggest.

METHODS

A structured postal questionnaire was sent to all GP of the north-west region of France, asking physicians about obstacles perceived when taking care of depressive patients; factors influencing the use of services, specialised advice, treatments, access to psychiatrists and psychological care. Their psychiatric knowledge and demographic data were also assessed. Quantitative data were analysed using Epi-Info software, and qualitative data were transcribed and coded manually.

RESULTS

A total of 25% of the GP returned the questionnaire (n=2097 in 8709). The sample profile was the same as the studied population. Less than a third of the GP (28%) were aware of the clinical guidelines on depression, and less than a fifth (18%) had clinical experience of psychiatry during their studies. Lack of time was not the main obstacle assessed by the GP. Their complaints were about lack of mental health services, difficulty in accessing services, and about general liaison between primary and secondary health care services: they reported difficulties obtaining quick and good response from the specialist either for emergency or non emergency cases. Regarding secondary care, they mainly referred to the psychiatrist, rather than to the psychologist, probably because this second option is not reimbursed by the social security system. Not surprisingly, medication was cited as the most frequently used treatment, followed by psychotherapy and cognitive behavioral therapy (CBT), and almost never self help literature and self help groups. Trained GP considered they were much more comfortable coping with depressed patients, less frequently using secondary care providers, and easily alternative solutions rather than antidepressant drugs. This situation suggests the usefulness of medical education, and is attested by many qualitative answers.

DISCUSSION

It is not sure that the low rate of knowledge of the guidelines should be judged only as a lack of professionalism. According to the "French Society of Primary Care", clinical guidelines need updating, and it is known that those available could be useful only for half of the situations encountered in primary care. Operational propositions urgently need to be proposed. Recent questioning of the real interest of pharmaceutical options in the treatment of depression is another argument. Nor can we wait for a hypothetic rise in the demographic situation. The GP have several propositions to improve these problems, e.g. continuous medical education (CME) focusing on "patient centred therapy", dedicated hotline or circuit for depressed people, and an adapted sociomedical directory. They also feel that political awareness about lack of physicians is required, but say that improving quality of care does not rely only on improving demographics. They ask for funds for psychological care. When thinking about the circuit of care, the role of all care providers, and their communication, a global vision appears unavoidable, which would get rid of the divisions between out-patients and the hospital.

CONCLUSION

Despite an unavoidable questioning on the dysfunctions of the health care system, quality of care and probably pharmaceutical consumption for the depressed patient might be improved by simple tools, such as adapted CME for primary care physicians, and communication improvement between secondary and primary care systems.

Genetic characterization of Toxoplasma gondii from wild boar (Sus scrofa) in France

Toxoplasma gondii strains isolated from domestic animals and humans have been classified into three clonal lineages types I-III, with differences in terms of pathogenicity to mice. Much less is known on T. gondii genotypes in wild animals. In this report, genotypes of T. gondii isolated from wild boar (Sus scrofa) in France are described. During the hunting seasons 2002-2008, sera and tissues of individuals from two French regions, one continental and one insular, were tested for Toxoplasma infection. Antibodies to T. gondii were found in 26 (17.6%) of 148 wild boars using the modified agglutination test (MAT, positivity threshold: 1:24). Seroprevalence was 45.9% when considering a threshold of 1:6. Hearts of individuals with a positive agglutination (starting dilution 1:6) (n=60) were bioassayed in mice for isolation of viable T. gondii. In total, 21 isolates of T. gondii were obtained. Genotyping of the isolates using 3 PCR-restriction fragment length polymorphism markers (SAG1, SAG2 and GRA7) and 6 microsatellite loci analysis (TUB2, TgM-A, W35, B17, B18 and M33) revealed that all belonged to type II lineage. These results underline that wild boar may serve as an important reservoir for transmission of T. gondii, and that strains present in wildlife may not be different from strains from the domestic environment.

Microsatellite markers in Triatoma pseudomaculata (Hemiptera, Reduviidae, Triatominae), Chagas' disease vector in Brazil

Six polymorphic microsatellite loci were isolated and characterized using a microsatellite-enriched genomic library from the Chagas' disease vector Triatoma pseudomaculata. This species is found in Brasil in Caatinga areas and predominantly in peridomestic habitats. All the microsatellites tested on a population of T. pseudomaculata sampled in the Bahia State, Brazil, were polymorphic (2-15 alleles). Markers amplification was also tested on six Triatoma species and some loci successfully amplified in the most phylogenetically related species, in particular Triatoma brasiliensis.

Anomalous roughening of viscous fluid fronts in spontaneous imbibition

We report experiments on spontaneous imbibition of a viscous fluid by a model porous medium in the absence of gravity. The average position of the interface satisfies Washburn's law. Scaling of the interface fluctuations suggests a dynamic exponent z approximately 3, indicative of global dynamics driven by capillary forces. The complete set of exponents clearly shows that interfaces are not self-affine, exhibiting distinct local and global scaling, both for time (beta = 0.64 +/- 0.02, beta(*) = 0.33 +/- 0.03) and space (alpha = 1.94 +/- 0.20, alpha(loc) = 0.94 +/- 0.10). These values are compatible with an intrinsic anomalous scaling scenario.

Consensus national sur la prise en charge des enfants dépistés avec une hyperphénylalaninémie

Phenylketonuria (PKU) is an inherited metabolic disease affecting about one birth out of 15 000. From 1978, a national systematic neonatal screening was set up in France with a regional organisation. French rational and guidelines have been established by the national PKU group with the collaboration of all the physicians responsible for the regional centres. These guidelines specify the minimal diagnosis procedures leading to an optimal treatment of all patients. A low-phenylalanine diet must be started as soon as possible in the neonatal period for all newborns whose phenylalanine levels are above 10 mg/dl. The dietary control must keep the phenylalanine plasma levels between 2 and 5 mg/dl until 10 years of age. After this age, several data argue for a progressive and controlled relaxation of the diet, keeping the phenylalanine level below 15 mg/dl until the end of the adolescence and below 20 to 25 mg/dl in adulthood. All PKU patients must be followed up for life, in order to screen those who may not bear the diet relaxation and in order to strictly prevent maternal PKU deleterious consequences.

Effect of enteral supplementation with glutamine on mesenteric blood flow in premature neonates

BACKGROUND AND AIMS

This study investigated the effects of enterally supplied glutamine on mesenteric blood flow in premature neonate.

METHODS

Twenty-five neonates, aged at least 14 days and free of acute illness participated in a prospective, randomised, double-blind study. All were fed with total enteral nutrition enriched with glutamine (0.7 g kg(-1)day(-1), group 1) or isonitrogenous control (group 2). Blood flow velocities in the superior mesenteric artery were analysed by pulsed Doppler US before and after 21 days of supplemented feeding. Peak systolic velocity (PSV), end-diastolic velocity (EDV) and time-averaged mean velocity (TAV) were measured and resistance index (RI) and flow (Q) were calculated.

RESULTS

Both groups were well matched clinically at inclusion. At inclusion, the velocimetry parameters were (mean +/- SD) : PSV:114.9 +/- -38 cms(-1), EDV:17.5 +/- 7.5 cm x s(-1), TAV:44.8 +/- 18.2 cms(-1), RI : 0.8 +/- 0.1, Q : 2.4 +/- 1.2 mls(-1). Mesenteric blood flow parameters remained stable between day 0 and day 21 with same values in both groups.

CONCLUSIONS

Superior mesenteric blood flow remained stable in neonates after 14 days of life and did not appear to be influenced by enteral glutamine at that stage.

Neonatal screening and long-term follow-up of phenylketonuria: the French database

BACKGROUND

In France, neonatal screening of phenylketonuria (PKU) started in 1966. A national association was created in 1978 in order to organise the neonatal screening program and to control the efficacy of the screening and patients' follow-up.

AIMS

To evaluate the results of the French PKU screening program in terms of hyperphenylalaninaemia epidemiology, efficacy of the screening procedure, management and outcome of the patients.

STUDY DESIGN

The national database has been filled-up first with the answers to questionnaires that were sent each year by the PKU patients' physicians, and second with the results of an additional inquiry, which was set up in 1994 in order to investigate diagnosis, treatment, and school outcome of all French PKU patients.

RESULTS

PKU was diagnosed in 81.6% of patients with hyperphenylalaninaemia (HPA), non-PKU HPA in 17.2% and cofactor deficiency in 1.1%. From 1980, incidence of PKU has been stable: 1 per 17,124 live births. Sensitivity of the screening procedure was 99.3%. Age at diet initiation regularly decreased to reach 14 days as a median in 1996. Until 1990, median age at diet discontinuation was 6 years of age. Later, strict diet was continued longer (at least, up to 8-10 years). PKU patients who entered to secondary school at normal age were characterised by an earlier age at diagnosis and at diet initiation and a later age at diet discontinuation, compared to those who entered 1 year or more behind normal age.

CONCLUSION

These data confirm the benefit of a nationwide organised screening program. They emphasise the importance of an early neonatal diagnosis and diet initiation in PKU patients and are consistent with the benefit of a longer period of strict diet in childhood.

Fetal and neonatal cerebral infarcts

Focal arterial infarction in the full-term newborn is an important cause of acquired cerebral lesions in the perinatal period. Clinical motor seizures, most often unifocal, are the nearly constant disclosing symptom confirmed by focal EEG abnormalities. A multifactorial physiopathology is usual, including genetic and perinatal environmental factors. In the past decade, various acquired or genetic thrombophilias have been discussed as risk factors. For several of the involved mechanisms, the excitotoxic cascade could represent a common final pathway leading to neuronal cell death. Early magnetic resonance imaging studies and EEG help to identify the newborns with strokes who are likely to develop hemiplegia and disabilities at school. Protection of the human fetal brain remains difficult, since the triggering factor initiating the excitotoxic cascade is rarely observed. Treatment of seizures is nevertheless necessary, because it seems that they accelerate anoxia-induced neuronal death in animal models of focal hypoxic ischemia.