Micro and macro population effects in disease transmission: the case of varicella.

Profiles of varicella-zoster virus (VZV) seroprevalence have shown large variability in European countries in which vaccination has not been implemented. Differences in micro and macro population structures (e.g. household and municipality, respectively) may explain such variability, which is the focus of a population-based study of varicella in 12,000 children from 7800 French households in Corsica. The cumulative incidence was 89% at age 11 years, as the median age at infection was 5 years in first-born children, but decreased to 3.9 years in younger siblings. Hazard of infection in households increased as the first-born child initially enrolled in primary school. Age at infection was higher in less populated areas. Household attack rates increased with age (55% in <6 months, >90% in >3 years) and household secondary attack rate was approximately 70%. Several levels of population structure independently affect age at varicella infection.

Dual infections by influenza A/H3N2 and B viruses and by influenza A/H3N2 and A/H1N1 viruses during winter 2007, Corsica Island, France.

BACKGROUND: The investigation of dual influenza infection human cases is of major interest specifically for the control of new emerging influenza strains. OBJECTIVES: Using RT-PCR assays, we retrospectively assessed the prevalence of dual influenza virus infections that occurred in patients during the 2006-2007 winter season in Corsica Island (France). STUDY DESIGN: One hundred and thirty-four nasal swabbing samples taken from patients suffering from influenza-like illness between February and March 2007 were analysed using a rapid influenza antigen detection test, cell culture and RT-PCR assays. RESULTS AND CONCLUSION: Influenza viruses were detected in 93 (69.4%) of 134 patients with influenza-like illness using the combination of classical and molecular assays. Dual respiratory infections by influenza viruses were detected in 3 (3.2%) of the 93 influenza positive patients, including two cases of infection by influenza A/H3N2 and B viruses and one case of dual infection by influenza A/H3N2 and A/H1N1 viruses. In the present report, human co-infection cases by two influenza viruses appeared as a rare event in symptomatic patients. However, the virological and epidemiological mechanisms that determine the occurrence of dual influenza infections remain to be fully investigated in further prospective multicentric studies.

Cholesteryl ester transfer protein gene polymorphisms are associated with coronary artery disease in Corsican population (France).

The aim of the present study was to investigate the association between coronary artery disease (CAD) and Cholesterol Ester Transfer Protein (CETP) (gaaa)n polymorphisms of the CETP gene in Central Corsica island (France). The study group was composed by 300 unrelated Corsican patients with angiographically documented CAD and 300 unrelated healthy blood donors. Significant differences were observed in the distribution of CETP (gaaa)n alleles between the groups under study (p=0.03; chi(2): 16.8, df: 8). The occurrence of a long allele (408 bp) was higher in cases (12%) than in control group (2%), showing a 6.75-fold increased risk for CAD in Corsica patients (p=0.0055; OR=6.750; 95% CIs=1.47-31.00). The correlation of this polymorphism with the lipid profile (cholesterol, low density lipoprotein-cholesterol, high density lipoprotein-cholesterol and triglycerides) in the patients group was determined. There was a significant association of the long alleles of CETP (gaaa)n with HDL-C levels. In the patient and in the control groups the LL genotypes had lower HDL-C compared with the SS and SL genotypes (p<0.0001). In summary our results suggest that the genetic variation at the CETP gene may play an important role in determining CAD in Corsican population.

Molecular variation of HLA class I genes in the Corsican population: approach to its origin.

Three human leucocyte antigen (HLA) class I loci (HLA-A, -B and -Cw) were typed for the first time at the DNA level in the Corsican population. This analysis was performed on 100 individuals of Corsican origin living in central Corsica (46 individuals) and in south-western Corsica (54 individuals). The genetic structure of these two subpopulations was analysed on the basis of the molecular polymorphisms of the HLA-A, -B and -Cw genes. A phylogenetic and a haplotypic analysis were performed. The genotypic analysis did not detect genetic differentiation. Examination of the allelic and haplotypic frequencies did, however, reveal some significant differences between the two zones. Similarities with the Sardinian population were found, and were particularly evident in the south-western sample. However, Corsica has probably been subject to greater West European influence, which can be seen in the Corte sample (Haute Corse).

West Mediterranean islands (Corsica, Balearic islands, Sardinia) and the Basque population: contribution of HLA class I molecular markers to their evolutionary history.

The genetic structure of Balearic islands (Corsica and Sardinia), situated on the same trans-Mediterranean maritime routes and having very similar histories, were compared and their position among the neighbouring Caucasian populations was inferred. For this purpose, three HLA loci (HLA-A, -B and -Cw) were typed at the DNA level in these populations and the allelic and haplotypic frequencies were estimated. Because previous studies have shown common genetic features in the Sardinians and Basques, HLA-Cw molecular typing was also performed in a sample of French Basques in order to establish the haplotypic structure of this population for a more accurate comparison with the three others. By its allelic composition, the Corsican population has an intermediate position between the two other islander populations. Its close relationship with the Sardinian population, however, was clearly revealed by the phylogenetic analysis which also suggests a proximity with eastern Mediterranean peoples, whereas the Balearic islands are more narrowly related to Spain and western Europe. Peculiarities were observed in the distributions of some common haplotypes in the populations of the islands that confirm the results of the phylogenetic analysis and could be related to their history. Noteworthy is the presence of the HLA-A30-Cw*0501-B18 haplotype at frequencies approximately 2% in Corsica and the Balearic islands, yet the estimated frequencies of this haplotype are much lower than in the Sardinian and Basque populations.

[Medical and Human Biological Sciences department of the University of Corsica as a tool for public health development]. / Le Département de Sciences médicales et de biologie humaine de l'Université de Corse comme un outil de développement en Santé publique.

To overcome the difficulties of access to training in health and the absence of biomedical research, the territorial community of Corsica recommended the implementation of a Department of Medical Sciences and Human Biology within the University of Corsica. It is within the framework of this department that different training courses targeting the full range of actors in the health system were organised, the large majority in agreement with medical faculty from the continent. It is also within this framework that a set of research themes was developed, permitting at full term, a better health management of the population. After four years in existence, we propose an assessment of training actions, and the results of the research work that associated hospital practitioners and university research professors and which allows one to imagine, notably, the development of a research axis in geography and health on the theme, "Genetics-Public Health-Environment in the Islands of the Mediterranean".

HLA-DMA alleles are possible new markers of rheumatoid arthritis: study of a Corsican group.

The HLA-DMA gene, along with the HLA-DMB gene, encodes the not classical class II molecule. This molecule catalyzes the class-II-associated invariant-chain peptide (CLIP)-antigen peptide exchange in classical class II molecule peptide-binding groove. As such, the DM heterodimer is an antigen presentation regulator and may be linked to immune system deficiencies such as those observed in autoimmune diseases. The study of DMA gene polymorphism seems be a reasonable approach to provide an answer to this question. Thanks to PCR-derived methods, the relationship between DMA gene polymorphism and rheumatoid arthritis (RA) was demonstrated in the present study. The DMA*0101 allele was observed to confer a significant predisposition to RA while the DMA*0102 allele significantly protected from this disease. Polymorphism experiments with the HLA-DRB1 gene revealed that this relationship between DMA polymorphism and RA is not a consequence of a linkage disequilibrium with the HLA-DRB1 alleles implicated in this pathology. The study of the DMA gene could therefore prove to be very useful in the early diagnosis of RA.

Implication of HLA-DMA alleles in corsican IDDM.

The HLA-DM molecule catalyses the CLIP/antigen peptide exchange in the classical class II peptide-binding groove. As such, DM is an antigen presentation regulator and may be linked to autoimmune diseases. Using PCR derived methods, a relationship was revealed between DM gene polymorphism and IDDM, in a Corsican population. The DMA*0101 allele was observed to confer a significant predisposition to this autoimmune disease while the DMA*0102 allele protected significantly. Experiments examining polymorphism of the HLA-DRB1 gene established that these relationships are not a consequence of linkage disequilibrium with HLA-DRB1 alleles implicated in this pathology. The study of the DMA gene could therefore be an additional tool for early IDDM diagnosis in the Corsican population.

Population history of Corsica: a linguistic and genetic analysis.

Genetic and linguistic differentiations within Corsica were analysed and compared; the genetic relationships of Corsica to other Mediterranean populations were also studied. Lexical distances between 49 Corsican localities were computed from a standard word list; trees built from these distances were compared with average linkage and neighbour-joining trees of genetic distances. Our lexical distance results confirmed the north/south dialectal subdivision of Corsican speeches described by linguists. No clear results were achieved with genetic distances because of the low number of loci for which data were available. Nevertheless, a tight northern cluster clearly emerged. When compared to other Mediterranean populations, Corsica showed a certain degree of differentiation, although not so marked as that of Sardinia. Corsica presented genetic affinities with Campania, Sicily, Liguria, Provence and Latium, while distances with Tuscany and Sardinia were larger. These results can be interpreted as a reflection of the prehistoric isolation of Corsica and the relative contribution to the island gene pool of prehistoric and historic invaders and immigrants from several populations.

[Polymerase chain reaction, cold probes and clinical diagnosis]. / Réaction de polymérisation en chaîne, sondes froides et diagnostic clinique.

Until 1985 the only way to study a gene was to clone it. Henceforth, the polymerase chain reaction (PCR) is an alternative method for synthesizing millions of copies of a specific DNA sequence. Without the development of non radioactive probes, these technologies would have been reserved for research applications. PCR with non radioactive probes is a powerful tool of molecular diagnosis in routine laboratories (identification of viruses and bacteria, diagnosis of human genetic diseases). PCR is based on Taq DNA polymerase. This enzyme is able to polymerize deoxynucleotide precursors (dNTP) in a temperature range of 75-80 degrees C. A typical PCR reaction is a repetitive series of thermic cycles involving template DNA denaturation, oligonucleotide primer annealing, and extension of the annealed primers by DNA polymerase. This three-step process results in the exponential accumulation of a specific fragment whose termini are defined by the 5' end of the primers. Amplification can be estimated to be 2n, where n is the number of cycles. The first step involves denaturation of double-stranded target DNA by heating the sample to 90-95 degrees C. In the second step, the temperature is lowered to about 5 degrees C below the melting temperature of the primer, assuring the specificity of the primer annealing and thus the specificity of the product. The third step is carried out by raising the temperature of the sample to 70-73 degrees C, the optimal temperature for primer extension, involving very little denaturation of the enzyme during the 25-30 cycles of a PCR reaction. The primers used are designed on the basis of the known DNA sequence and they must flank the sequence targeted. For microorganism typing, a product of 300 to 900pb can be amplified, though a 2 kb product can be synthesized. The choice of the primer sequence is a function of the target and technical requirements, such as a GC content of 50-60%, which gives the optimal annealing temperature of 50-55 degrees C. The molecular composition of the primer must be chosen to prevent the formation of intra-molecular secondary structures and primer dimers. The complementarity between the template and the 3' OH end must be perfect, because Taq DNA polymerase activity is markedly lowered by mismatches and secondary structures. The 5' end can thus modified by extension or base modification without altering the quality of the amplification. The yield of the reaction can be modified by the composition of the PCR medium.(ABSTRACT TRUNCATED AT 400 WORDS)

[Direct clamping of the right lateral pedicle of Glisson's capsule. Anatomicosurgical study in a case of hepatocaval injury]. / Clampage direct du pédicule glissonien latéral droit. Etude anatomo-chirurgicale à propos d'un cas de traumatisme hépato-cave.

A patient with hepatocaval injuries was treated successfully by direct suprahepatocaval hemostasis, and right lateral sectoriectomy after elective extrafascial clamping of Glisson's capsule. Anatomical conditions favorable for clamping were assessed from data in the published literature, and a personal series in which this technique was employed. A Gans' incision of at least 20 mm in length conditions the possibility of direct control of the right lateral pedicle, and was performed in 65 to 80 p. cent of cases. The proximal part of the incision reveals only the anterior border of the lateral pedicle where as the distal portion uncovers the first important right anterior pedicle of the segment VI, this being observed most frequently. At this level, extrafascial isolation of the lateral pedicle is usually rapid and precise (approximately 70 p. cent of cases). Adaptation of treatment of lesions of the homonymous sector is then possible under controlled surgical conditions of comfort and safety.

[Primary odditis. Clinical features, therapy, and possible pathogenesis (author's transl)]. / Les oddites primitives. Etude clinique et thérapeutique. Essai d'interprétation pathogénique.

Primary odditis, a rare affection, was observed in 28 patients (15 women and 13 men) with a mean age of 56.4 years. Epigastric or right hypochondrial pain was the presenting symptom in 13 cases, while in 13 others the onset was heralded by jaundice, either of a chronic nature (2 cases) or of the pseudo-lithiasic type (11 cases). The pancreatic form is much less frequent (2 cases). Radiological and histological findings are compared with those described in the published literature. All patients demonstrated a specific psychosomatic profile. Primary odditis can be reproduced experimentally in dogs by chronic irritation of the right splanchnic nerve, this acting on a nerve circuit which includes the right splanchnic and left vagus nerves. It is suggested that such lesions are secondary to a "nervous irritation" (Reilly's phenomenon). Treatment of primary odditis is by surgery only, sphincterectomy giving the best results, though choledochoduodenal anastomosis is also effective in elderly patients.

In vivo effect of 13 Leu motilin on the electric activity of the rabbit sphincter of Oddi.

Myoelectrical activity of the sphincter of Oddi was studied in 15 anaesthetized and laparotomized male rabbits, before and after injection of various doses of 13 Leucine Motilin (13 L Motilin), a biological and structural analogue of natural motilin. It can be concluded that 13 L Motilin provoked an increase of the sphincter of Oddi spike activity with doses ranging from 0.1 to 1.6 x 10(-6) g/kg. This effect had begun one minute after the injection, reached its maximum at the second minute and lasted for fifteen minutes. The action of 13 L Motilin is dose-related between 0.2 and 0.6 x 10(-6).

Action of gastrointestinal hormones on the myoelectric activity of the sphincter of Oddi in living rabbit.

The aim of this work was to compare the action of gastrointestinal (GI) hormones on the myoelectrical activity of the sphincter of Oddi. Using an experimental design previously described, we studied the electrical activity of the sphincter of Oddi and compared the percentage variation in the number of spikes before and after injection of hormones. Increasing doses of the following hormones were injected i.v. at random: CCK, OP-CCK, caerulein, bombesin, gastrin, secretin and glucagon. CCK and caerulein (as previously found), and also bombesin, OP-CCK and gastrin increased the spikes activity of the sphincter of Oddi. Secretin had no effect and glucagon decreased this activity. There was no tachyphylaxis, but a good dose-effect relationship for each hormone. Compared on a molar basis caerulein is 8 times more effective than CCK and OP-CCK which in turn are more potent than bombesin. Gastrin acts only at pharmacological doses.