Prevalence of Factor V Leiden in Patients with Myocardial Infarction and Normal Coronary Angiography

Factor V Leiden is associated with an increased risk of venous thrombosis and myocardial infarction in young women, but not in men in this latter case. The aim of this study was to evaluate the prevalence of this mutation in patients with myocardial infarction but normal coronary angiography.

We compared 3 groups of patients: one group consisted of 107 patients with premature myocardial infarction but no significant coronary artery stenosis; another group of 244 patients with myocardial infarction and significant coronary artery stenosis; a third group of 400 healthy controls.

Factor V Leiden was found in 13 patients (12.1%) who had a myocardial infarction without significant coronary artery stenosis, 11 patients (4.5%) who had a myocardial infarction with significant coronary artery stenosis (p = 0.01) and in 20 controls (5%) (p = 0.01). Odds ratio associated with factor V Leiden were respectively 2.93 (CI95 : 1.18-7.31) and 2.63 (CI95 : 1.19-5.78) when we compared myocardial infarction patients without significant coronary artery stenosis to controls or to patients with significant coronary artery stenosis.

In myocardial infarction patients without significant coronary artery stenosis, prevalence of factor V Leiden is significantly higher than in controls. This new finding supports the hypothesis that thrombosis plays a key role in this selected situation.

Prevalence of 20210 A Allele of the Prothrombin Gene in Venous Thromboembolism Patients

Background. The 20210 A allele variation in the 3’ -untranslated region of the prothrombin gene was recently identified as a risk factor as regards deep venous thrombosis. Aim. To assess the frequency of the variation in unselected patients with a proven venous thromboembolism (VTE). Methods. The presence of the prothrombin variation was determined in all consecutive patients referred from July 1994 to August 1997 for a clinical suspicion of VTE, and in whom the diagnosis was confirmed. A control group consisted of bone marrow volunteer donors. Results. Of the 366 patients included, 17 (4.6%) were carriers of the 20210 A allele (95% CI, 2.4% to 6.7%). The mutation was present in 1.0% of the 400 controls. Odds ratio for having VTE in the presence of the 20210 A allele was 4.8 (95% CI, 1.5 to 19.8). Forty-six (12.5%) patients had the mutation of the factor V gene and five (1.4%) patients shared both mutations. After excluding the carriers of the factor V mutation, odds ratio for having VTE in the presence of the 20210 A allele was 3.7 (95% CI, 1.1 to 13.6). Mean age at admission as well as mean age of the first VTE episode were both significantly higher in patients free from the two mutations studied, as compared to carriers of the 20210 A allele (p = 0.04 and 0.01, respectively). Conclusion. Our findings in a large series of patients (1) confirm the 20210 A allele prothrombin gene as a risk factor for VTE. (2) suggest that its association with the factor V Leiden is not uncommon.

Incidence of venous thromboembolism in first-degree relatives of patients with venous thromboembolism who have factor V Leiden

The factor V Leiden (FVL) mutation, a genetic abnormality with an autosomal mode of inheritance, is associated with an increased risk of venous thromboembolism (VTE). We aimed to determine the annual incidence of VTE in first-degree relatives of patients with VTE and FVL and to identify factors in patients and the relatives that influence this incidence. In this retrospective and prospective cohort study, the incidence of objectively diagnosed first episodes of VTE was assessed in 553 first-degree relatives of 161 patients with acute VTE and FVL. The annual incidence of VTE was 0.43% (95% CI, 0.3 to 0.56) with FVL and 0.17 % (95% CI, 0.07 to 0.27) without FVL (relative risk of 2.5, 95% CI, 1.3 to 4.7). A majority (70%) of episodes of VTE were provoked, and this proportion was similar with and without FVL. A larger proportion of VTE was provoked in women (83%) that in men (33%), with the difference accounted for by pregnancy and use of oral contraceptives. The proportion of pregnancies complicated by VTE was 3.9% (95% CI, 2.0–5.8) with FVL and 1.4% (95% CI, 0.04–2.7) without FVL. FVL is associated with a two-to threefold increase in VTE in first-degree relatives of patients with VTE. No subgroup of relatives was identified who require more than routine prophylaxis because of a particularly high risk of VTE.

Association of common genetic variations and idiopathic venous thromboembolism

Venous thromboembolism (VTE) is a multifactorial disease, caused by interacting environmental and genetic risk factors. Gene-centric geno-typing strategy is one of the approaches to explore unexplained associations between risk factors and VTE. It was the objective of this study to evaluate, using a gene-centric genotyping strategy, polymorphisms in genes involved in the following pathways: coagulation cascade process, renin-angiotensin or adrenergic systems, lipid metabolism, platelet aggregation. Allele frequency was compared between 677 cases with idiopathic VTE and their matched controls. After Bonferroni adjustment, four single nucleotide polymorphisms (SNPs) were significantly associated with VTE: Factor XI rs925451 polymorphism, factor XI rs2289252 polymorphism, factor II rs1799963 (G20210A) polymorphism and factor V Leiden rs6025. An additive mode of inheritance fitted best both factor XI polymorphisms. In this hospital-based case-control study, two polymorphisms located on the factor XI gene were significantly associated with VTE. Other newly investigated polymorphisms with potentially false negatives may warrant further analyses.

Predicting pathogen-specific CD8 T cell immune responses from a modeling approach

The primary CD8 T cell immune response constitutes a major mechanism to fight an infection by intra-cellular pathogens. We aim at assessing whether pathogen-specific dynamical parameters of the CD8 T cell response can be identified, based on measurements of CD8 T cell counts, using a modeling approach. We generated experimental data consisting in CD8 T cell counts kinetics during the response to three different live intra-cellular pathogens: two viruses (influenza, vaccinia) injected intranasally, and one bacteria (Listeria monocytogenes) injected intravenously. All pathogens harbor the same antigen (NP68), but differ in their interaction with the host. In parallel, we developed a mathematical model describing the evolution of CD8 T cell counts and pathogen amount during an immune response. This model is characterized by 9 parameters and includes relevant feedback controls. The model outputs were compared with the three data series and an exhaustive estimation of the parameter values was performed. By focusing on the ability of the model to fit experimental data and to produce a CD8 T cell population mainly composed of memory cells at the end of the response, critical parameters were identified. We show that a small number of parameters (2-4) define the main features of the CD8 T cell immune response and are characteristic of a given pathogen. Among these parameters, two are related to the effector CD8 T cell mediated control of cell and pathogen death. The parameter associated with memory cell death is shown to play no relevant role during the main phases of the CD8 T cell response, yet it becomes essential when looking at the predictions of the model several months after the infection.

Curative vs. preventive management of nitrogen transfers in rural areas: lessons from the case of the Orgeval watershed (Seine River basin, France)

The Orgeval watershed (104 km(2)) is a long-term experimental observatory and research site, representative of rural areas with intensive cereal farming of the temperate world. Since the past few years, we have been carrying out several studies on nitrate source, transformation and transfer of both surface and groundwaters in relation with land use and agriculture practices in order to assess nitrate (NO3(-)) leaching, contamination of aquifers, denitrification processes and associated nitrous oxide (N2O) emissions. A synthesis of these studies is presented to establish a quantitative diagnosis of nitrate contamination and N2O emissions at the watershed scale. Taking this watershed as a practical example, we compare curative management measures, such as pond introduction, and preventive measures, namely conversion to organic farming practices, using model simulations. It is concluded that only preventive measures are able to reduce the NO3(-) contamination level without further increasing N2O emissions, a result providing new insights for future management bringing together water-agro-ecosystems.

Psychological effect of exercise in women with breast cancer receiving adjuvant therapy: what is the optimal dose needed?

BACKGROUND

Several meta-analyses have examined the role of exercise interventions in improving psychological outcomes in cancer survivors but most did not focus on adjuvant therapy period and did not investigate the optimal dose of exercise needed. The present meta-analysis examines the impact of exercise interventions delivered at this particular period on fatigue, anxiety, depression, and quality of life (QoL) as well as dose-response relationships between volume of prescribed exercise and these psychological outcomes.

MATERIALS AND METHODS

Randomized, controlled trials that proposed an exercise intervention to patients with breast cancer undergoing chemotherapy and/or radiotherapy were systematically identified and coded. Psychological outcomes effect sizes were calculated and analyzed for trends using linear and quadratic regressions.

RESULTS

Pooled effects of the 17 included studies revealed improvement for all outcomes, significant for fatigue, depression, and QoL with pooled estimates ranging from 0.2 to 0.5 favoring intervention. Significant inverse associations of the volume of prescribed exercise with fatigue and QoL were observed.

CONCLUSIONS

Exercise intervention improved fatigue, depression, and QoL in patients with breast cancer receiving adjuvant therapy. Prescription of relatively low doses of exercise (<12 MET h/week) consisting in ∼90-120 min of weekly moderate physical exercise seems more efficacious in improving fatigue and QoL than higher doses.

Bubble production mechanism in a microfluidic foam generator

We present the design and characterization of a microfluidic bubble generator that has the potential of producing monodisperse bubbles in 256 production channels that can operate in parallel. For a single production channel we demonstrate a production rate of up to 4 kHz with a coefficient of variation of less than 1%. We observe a two-stage bubble production mechanism: initially the gas spreads onto a shallow terrace, and then overflows into a larger foam collection channel; pinning of the liquid-gas meniscus is observed at the terrace edge, the result being an asymmetric pinch-off. A semiempirical physical model predicts the scaling of bubble size with fluid viscosity and gas pressure from measurements of the pinned meniscus width.

Inherited thrombophilias and unexplained pregnancy loss: an incident case-control study

BACKGROUND

Despite an initial impressive impact, a critical appraisal of the link between pregnancy loss and inherited thrombophilias is currently growing. Furthermore, little is known about the paternal thrombophilic phenotype and pregnancy loss.

OBJECTIVE

We sought an association between unexplained pregnancy loss and parental factor V Leiden (FVL) and Prothrombin G20210A (PTG) mutations.

METHODS

Design - Incident case-control study. Setting- University Hospital of Brest (France). Patients - Women and their partners from the West Brittany area, consecutively referred for unexplained pregnancy losses (two or more consecutive losses at or before 21 weeks of gestation, or at least one later loss). Controls - Women and their partners with no history of pregnancy loss and at least one normal pregnancy, from the same geographic area, recruited using electoral lists. Statistical analysis - Comparison of FVL and PTG allele frequency between cases and controls using the chi-square test. Separate analyses were performed according to the type of pregnancy loss (early recurrent or later loss).

RESULTS

311 women (mean age: 32.8) and 284 of their partners were enrolled as cases while 599 women (mean age: 34.3) and 297 of their partners were recruited as controls. The prevalence of female, male or couple thrombophilic mutations was not statistically different between cases and controls whatever the definition of pregnancy loss retained.

CONCLUSIONS

Presently, there is no clinical indication to routinely test for FVL and likely PTG mutations in women with early recurrent pregnancy loss. Moreover, our results did not reveal that paternal thrombophilic polymorphism should be further explored.

CFTR mutations in the Algerian population

The nature and frequency of the major CFTR mutations in the North African population remain unclear, although a small number of CFTR mutation detection studies have been done in Algeria and Tunisia, showing largely European mutations such as F508del, G542X and N1303K, albeit at different frequencies, which presumably emerged via population admixture with Caucasians. Some unique mutations were identified in these populations. This is the first study that includes a genetic and clinical evaluation of CF patients living in Algeria. In order to offer an effective diagnostic service and to make accurate risk estimates, we decided to identify the CFTR mutations in 81 Algerian patients. We carried out D-HPLC, chemical-clamp denaturing gradient gel electrophoresis, multiplex amplification analysis of the CFTR gene and automated direct DNA sequencing. We identified 15 different mutations which account for 58.5% of the CF chromosomes. We used a quantitative PCR technique (quantitative multiplex PCR short fragment fluorescence analysis) to screen for deletion/duplication in the 27 exons of the gene. Taking advantage of the homogeneity of the sample, we report clinical features of homozygous CF patients. As CFTR mutations have been detected in males with infertility, 46 unrelated Algerian individuals with obstructive azoospermia were also investigated.

Multicenter trials need to use the same assay for hepatitis C virus viral load determination

This study, involving 20 laboratories and using currently available assays for hepatitis C virus RNA quantification, demonstrated that differences in viral load values are due not to interlaboratory variations but rather to the nature of the assay itself. This underlines the importance of using the same assay in multicenter studies or when monitoring antiviral therapy.

Vitamin K epoxide reductase genetic polymorphism is associated with venous thromboembolism: results from the EDITH Study

BACKGROUND

The vitamin K epoxide reductase complex subunit 1 (VKORC1) recycles endogenous vitamin K, a cofactor for vitamin K-dependent coagulation factor synthesis. Common polymorphisms in VKORC1, the gene coding for VKORC1, have been found to affect the dose response to vitamin K antagonists, and to confer an increased risk of vascular diseases in a Chinese population. The aim of this study was to evaluate the association between the VKORC1 1173C > T polymorphism and venous thromboembolism (VTE).

METHODS

We report the results of a case-control study designed to evaluate interactions between acquired and inherited risk factors of VTE. We studied 439 cases hospitalized with a first venous thromboembolic event that was not related to a major acquired risk factor for VTE, and 439 matched controls. The VKORC1 1173C > T polymorphism was selected for genotyping as the tagging single-nucleotide polymorphism for previously identified VKORC1 haplotypes.

RESULTS

The relationship between VTE and the VKORCI 1173C > T polymorphism was consistent with a recessive model. The frequency of the VKORCI TT genotype was lower in cases than in controls. The odds ratio (OR) (95% CI) was 0.62 (0.41-0.94) for the TT genotype as compared to CT/CC genotypes. Adjustment on cardiovascular diseases, body mass index, factor V (FV) and prothrombin gene mutations did not alter the results.

CONCLUSIONS

In this case-control study, the frequency of the VKORCI TT genotype was lower in patients with VTE than in matched controls. The clinical consequence of these results remains to be determined, but gives new perspectives for exploration of the role of VKORCI polymorphism in the pathogenesis of VTE.

Up-regulation of hippocampal serotonin metabolism in mild cognitive impairment

OBJECTIVE

Recent studies have suggested modifications of serotonin cerebral metabolism and of 5-HT(1A) receptors density in Alzheimer disease (AD). This study aims at exploring hippocampus 5-HT(1A) receptor density in patients at the amnesic mild cognitive impairment (aMCI) and mild AD dementia stages.

METHODS

With use of PET with a selective 5-HT(1A) antagonist, 2'-methoxyphenyl-(N-2'-pyridinyl)-p-[(18)F]fluoro-benzamidoethylpiperazine ([(18)F]MPPF), the hippocampus 5-HT(1A) binding potential (BP) was quantified in 10 patients with mild AD, in 11 patients with aMCI, and in 21 aged paired control subjects. To take into account hippocampal atrophy, a partial volume correction was applied to the [(18)F]MPPF data, leading to the calculation of a corrected BP (BP(c)). Comparison of hippocampus BP over populations was performed using Kruskal-Wallis rank analysis.

RESULTS

Hippocampus serotonergic receptor binding distinguishes patients from controls and patients with aMCI from patients with AD. In aMCI patients, the mean hippocampus BP(c) was 59% higher than the controls' (p < 0.005), and it was conversely 35% lower in patients with mild AD (p < 0.01). The difference in BP(c) values between patients with aMCI and mild AD was large, resulting in a p value of <0.0005. These differences were not related to hippocampus atrophy.

CONCLUSION

A compensatory mechanism illustrated by an up-regulation of serotonergic metabolism has been shown at the stage of amnesic mild cognitive impairment (aMCI) in contrast with a dramatic decrease at later stages of Alzheimer disease (AD). This difference of hippocampus serotonergic receptor labeling allows distinguishing of patients with aMCI from those with mild AD. Exploring 5-HT(1A) receptors with 2'-methoxyphenyl-(N-2'-pyridinyl)-p-(18)F-fluoro-benzamidoethylpiperazine PET seems to be of interest for better understanding pathophysiologic changes at early stages of AD.

Quantum confinement effect on Gd2O3 clusters

The evolution of the gap of a nanoscaled insulator material, namely, Gd(2)O(3), has been observed by means of vacuum ultraviolet excitation spectra of a dopant (Eu(3+)). The nanoparticles have been synthesized by the low energy cluster beam deposition technique and grown afterward by different annealing steps. A gap shift towards the blue is observed, similar to what is observed in semiconductor nanoparticles. Despite the strong ionic character of the material, the evolution exhibits a behavior similar to covalent materials. The evolution of the gap for Gd(2)O(3) follows the same empiric rule that has been derived for semiconductors (ZnO, CuBr, Si, and CdS). It shows that, in spite of the strong ionic character of the material (0.9 on the scale of Phillips), the amount of covalency is important enough for creating a significant delocalization of the electron with regard to its hole.

Estrogen receptor alpha polymorphism and venous thromboembolism in male and female: Data from the EDITH study

BACKGROUND

Association between estrogen receptor (ER) alpha polymorphism c.454-397 T>C and venous thromboembolism (VTE) has been reported in postmenopausal women. Comprehensive data are lacking. We herein evaluated the risk for VTE related to c.454-397 T>C ER alpha gene polymorphism in both men and women.

PATIENTS/METHODS

The EDITH Study enrolled consecutive patients, aged over 18 years, hospitalized between May 2000 and December 2004 in Brest University Hospital with an objectively proven symptomatic VTE. For each case, one control who matched the case for age within a five-year age band, gender and major acquired risk factors, was selected. The present analysis was restricted to 677 cases with a VTE event not related to major acquired risk factors and their matched controls.

RESULTS AND CONCLUSIONS

The relationship between VTE and c.454-397 T>C ER alpha polymorphism was consistent with a dominant model in women and a recessive model in men. Adjusted conditional odds ratios (95% CI) were 1.37 (1.05-1.78) and 1.29 (0.85-1.94) for CT/CC genotypes in women and CC genotype in men respectively compared to TT genotype. Among women hormone use did not substantially modify effect-measure estimate. Our results further extend results from previous studies. Other investigations are required to precise underlying mechanisms.

Incidence of venous thromboembolism in first-degree relatives of patients with venous thromboembolism who have factor V Leiden

The factor V Leiden (FVL) mutation, a genetic abnormality with an autosomal mode of inheritance, is associated with an increased risk of venous thromboembolism (VTE). We aimed to determine the annual incidence of VTE in first-degree relatives of patients with VTE and FVL and to identify factors in patients and the relatives that influence this incidence. In this retrospective and prospective cohort study, the incidence of objectively diagnosed first episodes of VTE was assessed in 553 first-degree relatives of 161 patients with acute VTE and FVL. The annual incidence of VTE was 0.43% (95% CI, 0.3 to 0.56) with FVL and 0.17% (95% CI, 0.07 to 0.27) without FVL (relative risk of 2.5,95% CI, 1.3 to 4.7). A majority (70%) of episodes of VTE were provoked, and this proportion was similar with and without FVL. A larger proportion of VTE was provoked in women (83%) that in men (33%), with the difference accounted for by pregnancy and use of oral contraceptives. The proportion of pregnancies complicated by VTE was 3.9% (95% CI, 2.0-5.8) with FVL and 1.4% (95% CI, 0.04-2.7) without FVL. FVL is associated with a two- to threefold increase in VTE in first-degree relatives of patients with VTE. No subgroup of relatives was identified who require more than routine prophylaxis because of a particularly high risk of VTE.

Interrelation of hyperhomocysteinemia and inherited risk factors for venous thromboembolism. Results from the E.D.I.TH. study: a hospital-based case-control study

BACKGROUND

Moderate hyperhomocysteinemia and factor V Leiden mutation are among the most prevalent risk factors for venous thromboembolism (VTE). The hypothesis of an interaction between those risks has been raised and conflicting results were reported.

METHODS

We designed a hospital-based case-control study to test the interaction between Factor V Leiden and fasting serum total homocysteine (tHcy). We have also analysed the G20210A prothrombin gene variant. This study enrolled 904 hospitalised patients who had an objectively proven deep vein thrombosis and/or pulmonary embolism as well as 904 hospitalised control patients matched for gender, age and major acquired risk factor for VTE.

RESULTS

Our data did not detect any multiplicative interaction between hyperhomocysteinemia (>15 mumol/L) and factor V Leiden mutation or G20210A prothrombin gene variant. Odds ratios (95% CI) were 4.0 (1.5-11) and 6.0 (1.3-27) for the combined effect of hyperhomocysteinemia with either factor V Leiden mutation or G20210A prothrombin gene variant, respectively.

CONCLUSIONS

Current data provide further knowledge in relationship between hyperhomocysteinemia and inherited risk factors, such as factor V Leiden mutation and G20210A prothrombin gene variant. As those risk factors are not so rare among Caucasians, a better estimate of the risk related to double exposure might help to optimise venous thromboembolism prevention.

Expertise of laboratories in viral load quantification, genotyping, and precore mutant determination for hepatitis B virus in a multicenter study

A national evaluation study was performed in 14 specialized laboratories with the objective of assessing their capacities to provide (i) hepatitis B virus (HBV) viral loads (VL), (ii) HBV genotypes, and(iii) identification of precore/core mutants. The panel consisted of 12 HBV DNA-positive samples with VLs from 2.8 to 9.1 log(10) copies/ml, different HBV genotypes (A to F), and 3 mutant and 9 wild-type samples at nucleotide 1896. The coefficients of variation of the mean VLs ranged from 2.4% to 10.4% with the Cobas HBV Monitor assay, from 1.8% to 5.5% with the Cobas TaqMan 48, from 1.5 to 26.2% with RealArt HBV PCR, and from 0 to 7% with branched DNA (bDNA). The Cobas Monitor assay underestimated the VLs of genotype F samples, with differences ranging from 1.4 to 2.4 log(10) copies/ml. The accuracies of genotype determinations ranged from 33% to 100%, and those of precore mutant determinations ranged from 25 to 100%. This study showed some drawbacks of two widely used assays: (i) Cobas Monitor has a narrow dynamic range and underestimates genotype F sample VLs and (ii) bDNA shows poor sensitivity and may fail to identify patients with low VLs. With higher performance in terms of analytical sensitivity combined with a larger dynamic range and an ability to quantify the main genotypes equally, real-time PCR methods appear more appropriate for accurate monitoring of HBV DNA quantification. Furthermore, the clinical implications of HBV genotyping and the determination of precore/core mutants need to be clearly stated to justify the standardization of these methods.

Salivary IgA Response of Triathletes Participating in the French Iron Tour

Athletes are susceptible to upper respiratory tract infections (URTI) during intense training and after major competitions. Secretory IgA, which is the predominant antibody of the mucosal immune system, is the major effector of host-resistance to many microorganisms causing URTI. Previous studies have shown that salivary IgA-mediated immunity decreases after a single short distance triathlon, but the effect of repeated triathlon competitions on secretory IgA levels remains unknown. The purpose of this study was to examine the salivary IgA response of elite triathletes in repeated triathlon races during the 2001 French Iron Tour (FIT). Eight triathletes participated in this study. Saliva samples were collected daily after waking up (fasting basal state), before (pre-race) and after (post-race) each day's competition. Salivary IgA, total protein, and flow rate were measured. Salivary IgA concentrations were measured by an enzyme-linked immunosorbent assay. The salivary flow rate was significantly decreased after each race compared with the fasting basal state (p < 0.01). The salivary IgA concentration of the fasting basal state decreased over the FIT and was even lower than that of the post-race values (p < 0.05). The salivary IgA secretion rate of the fasting basal state decreased by 51.9% over the FIT (p < 0.05). Our data suggest that intense exercise repeated daily has a cumulative negative effect on basal levels of salivary IgA.

High-resolution gamma-ray radiography produced by a laser-plasma driven electron source

An electron beam from a laser-plasma accelerator is converted into a gamma-ray source using bremsstrahlung radiation in a dense material. The gamma-ray beam has a pointlike source size because it is generated by a high quality electron beam with a small source size and a low divergence. Using this gamma-ray source, the radiography of complex and dense objects with submillimeter resolution is performed. It is the first evidence of a gamma-ray source size of a few hundreds micrometers produced with laser-driven accelerators. This size is consistent with results from Monte Carlo simulations.

Expertise of French laboratories in detection, genotyping, and quantification of hepatitis C virus RNA in serum

Before initiating new large-scale therapeutic trials for hepatitis C virus (HCV)-infected patients, the French Health Authorities for HCV research decided to organize an evaluation of the expertise of laboratories that could be engaged to undertake molecular biology assays in such trials; 21 experienced laboratories participated in this national evaluation of laboratory expertise, which was performed in two successive rounds. The first round evaluated the laboratories for their abilities to detect HCV RNA in serum, determine genotypes, and quantify HCV RNA loads. The results observed by qualitative assays for HCV RNA detection were 100% sensitivity and 100% specificity for all laboratories. The genotyping results were 100% concordant for 9 laboratories and greater than 90% for 10 laboratories. By contrast, large coefficients of variation were observed for quantitative determination of HCV RNA loads, leading to a second round with standardized quantitative assays only. The dispersion of the results was larger by the AMPLICOR HCV Monitor assay than by the branched-DNA assay (mean coefficients of variation, 57.4 and 16.9%, respectively). In the majority of cases, discrepancies between the results of the two tests were found for samples with high viral loads. These results indicate the usefulness of validating, by controlling for expertise, both the reliabilities of laboratories involved in multicenter work and the standardized assays chosen for use in the evaluation of the biological impacts of new therapies.

Synthesis and properties of europium-based phosphors on the nanometer scale: Eu2O3, Gd2O3:Eu, and Y2O3:Eu

Nanocrystals of oxides containing europium as the main constituent or as a doping element in RE2O3 ( RE=Y, Gd) have been prepared by direct oxide precipitation in high-boiling polyalcohol solutions and characterized by high-resolution TEM, absorption spectroscopy, and luminescence spectroscopy. The samples obtained consisted of concentrated and colloidally stable suspensions of luminescent oxide nanoparticles with an average grain diameter in the range 2-5 nm. The nanoparticles were found to be highly crystalline despite their ultrasmall size and the low temperature of 180 degrees C applied during the synthesis. Upon UV excitation, the red luminescence relative to the 5D0-->7Fn transition within the cubic form of RE2O3 exhibits some important differences from that usually found in bulk materials.

A combined analysis of the cystic fibrosis transmembrane conductance regulator: implications for structure and disease models

Over the past decade, nearly 1,000 variants have been identified in the cystic fibrosis transmembrane conductance regulator (CFTR) gene in classic and atypical cystic fibrosis (CF) patients worldwide, and an enormous wealth of information concerning the structure and function of the protein has also been accumulated. These data, if evaluated together in a sequence comparison of all currently available CFTR homologs, are likely to refine the global structure-function relationship of the protein, which will, in turn, facilitate interpretation of the identified mutations in the gene. Based on such a combined analysis, we had recently defined a "functional R domain" of the CFTR protein. First, presenting two full-length cDNA sequences (termed sCFTR-I and sCFTR-II) from the Atlantic salmon (Salmo salar) and an additional partial coding sequence from the eastern gray kangaroo (Macropus giganteus), this study went further to refine the boundaries of the two nucleotide-binding domains (NBDs) and the COOH-terminal tail (C-tail), wherein NBD1 was defined as going from P439 to G646, NBD2 as going from A1225 to E1417, and the C-tail as going from E1418 to L1480. This approach also provided further insights into the differential roles of the two halves of CFTR and highlighted several well-conserved motifs that may be involved in inter- or intramolecular interactions. Moreover, a serious concern that a certain fraction of missense mutations identified in the CFTR gene may not have functional consequences was raised. Finally, phylogenetic analysis of all the full-length CFTR amino acid sequences and an extended set of exon 13--coding nucleotide sequences reinforced the idea that the rabbit may represent a better CF model than the mouse and strengthened the assertion that a long-branch attraction artifact separates the murine rodents from the rabbit and the guinea pig, the other Glires.

Seroprevalence of human herpes virus 8 antibody in populations at high or low risk of transfusion, graft, or sexual transmission of viruses

BACKGROUND

The routes of transmission of human herpes virus 8 (HHV-8) remain unclear. In particular, HHV-8 transmission by blood components and organ transplantation is still debated and raises public health issues. The objective of this study was to determine the prevalence of anti-HHV-8 in selected populations of persons or patients with or without risk factors for the transmission of viral infections, in order to determine the routes of HHV-8 transmission.

STUDY DESIGN AND METHODS

A total of 1431 persons or patients at low or high risk of sexually, blood-, or graft-transmitted viral infections were tested by means of a standardized immunofluorescence serologic assay detecting anti-HHV-8.

RESULTS

The persons or patients could be classified into three distinct groups according to anti-HHV-8 prevalence: a low prevalence group (0.0% to 5.0%), including healthy blood donors, healthy pregnant women, multiply transfused patients with thalassemia major, and IV drug users; an intermediate prevalence group (5.0% to 20.0%), including organ donors, kidney transplant recipients, and multiply transfused patients with sickle cell disease; a high prevalence group (>20.0%), including HIV-negative persons at high risk of sexually-transmitted viral infections, and HIV-infected homosexual men and heterosexuals.

CONCLUSION

The sexual route appears to be the main route of HHV-8 transmission; bloodborne transmission of HHV-8, if it exists, is rare. In contrast, organ transplantation recipients might be exposed to HHV-8 transmission by the transplanted organ, which raises the issue of systematic screening of organ donors.

Venous blood lactate increase after vertical jumping in volleyball athletes

The aim of this study was to test the hypothesis that venous blood lactate concentrations ([La-]) would vary from the beginning of brief exercise. Maximal vertical jumping was used as a model of brief intense exercise. Eleven healthy male volleyball players, aged [mean (SE)] 18.5 (0.7) years, performed three exercise tests with different protocols, each separated by quiet seated recovery periods of 45 min. After the first test, consisting of a single maximal jump [lasting approximately equals 0.6 s for the pushing phase, and in which the subjects jumped 64 (2.2) cm], forearm venous [La-] increased significantly with respect to rest at 1 min (t1), 3 min (t3), and 5 min (t5) of recovery. The second test, comprising six maximal jumps, each separated by 20-s recovery periods, resulted in an unchanged [La-] with respect to the baseline value. After the third test [i.e., six consecutive maximal jumps that lasted a total of 7.36 (0.33) s], [La-] increased significantly at t3 and t5 with respect to the pre-test value (F= 10.3, P < 0.001). We conclude that a significant venous [La-] increase occurs after vertical jumping. This result may be explained by the activation of lactic anaerobic metabolism at the very onset of exercise, which participates in energy production and/or in the resynthesis of the phosphocreatine that was used during such brief exercise.

Methylenetetrahydrofolate reductase C677T genotype and venous thromboembolic disease

BACKGROUND

Many studies have suggested an increased risk of venous thromboembolism (VTE) in patients with mild hyperhomocysteinemia. The C677T mutation in the MTHFR gene has recently been described as a cause of mild hyperhomocysteinemia.

OBJECTIVES

To investigate the potential of the C677T mutation in the MTHFR gene in its homozygous state as a risk factor for VTE.

METHODS

Case-control study design. The presence of the mutation was determined in all consecutive patients referred from July 1994 to September 1997 and in whom the diagnosis was duly confirmed. Analysis was carried out in a subgroup of VTE patients free from both acquired and genetic risk factors (factor-V mutation and/or prothrombin gene mutation). A control group consisted of 105 volunteer blood donors.

RESULTS

In the 366 patients with a confirmed VTE, 253 presented acquired risk factors and 58 were carriers of the factor-V Leiden mutation and/or G20210A mutation of the prothrombin gene. In the remaining 55 patients, VTE was considered as 'unexplained', and the frequency of the C677T mutation MTHFR was 21.8% in its homozygous state and 34.5% in its heterozygous state. In the control group, 9.5% were found homozygous and 34.3% heterozygous. The odds ratio for having VTE in the presence of the mutation in its homozygous state was 2.9 (95% CI 1. 0-8.6).

CONCLUSION

This study suggests that the homozygous C677T mutation in the MTHFR gene might be a risk factor of VTE in patients with spontaneous events and without other common genetic risk factors.

Inheritance of a stable mutation in a family with early-onset disease

Autosomal/dominant polycystic kidney disease (ADPKD) exhibits a high inter- and intrafamilial heterogeneity partly explained by the involvement of at least 3 different genes in the disorder transmission. PKD1, the major locus, is located on chromosome 16p. The occurrence of very early-onset cases of ADPKD (sometimes in utero) in a few PKD1 families or the increased severity of the disease in successive generations raise the question of anticipation. This is a subject of controversial discussion. This report deals with the molecular analysis in families with very early-onset ADPKD. The finding of the same stable mutation with such different phenotypes rules out a dynamic mutation. The molecular basis of severe childhood PKD in typical ADPKD families remains unclear; it may include segregation of modifying genes or unidentified factors and the two-hit mechanism.

Prevalence of CFTR mutations in hypertrypsinaemia detected through neonatal screening for cystic fibrosis

Nowadays, most of the neonatal screening programs for cystic fibrosis (CF) combine the assay of immunoreactive trypsinogen (IRT) with the analysis of the most common mutations of the CFTR gene. The efficiency of this strategy is now well established, but the identification of heterozygotes among neonates with increased IRT is perceived as a drawback. We proposed to assess the heterozygosity frequency among the children with hypertrypsinaemia detected through the CF screening program implemented in Brittany (France) 10 years ago, to describe the CFTR mutations detected in them and to determine the frequency of the IVS8-5T variant. The molecular analysis relies, in our protocol, on the systematic analysis of three exons of the gene (7-10-11). A total of 160,019 babies were screened for CF in western Brittany between 1992 and 1998. Of the 1964 newborns with increased IRT (1.2%), 60 were CF and 213 were carriers. Heterozygosity frequency was 12.8%), i.e. 3 times greater than in the general population (3.9%; p < 10(-6)), Variability of mutations detected in carriers was greater than in CF children (21 mutations versus 10) and a high proportion of mild mutations or variants (A349V, R297Q, R347H, V317A, G544S, R553G, etc) was observed in carriers. The allelic frequency of the 5T (5.6%) was not significantly increased in this cohort. This study is consistent with previous ones in finding a significantly higher rate of heterozygotes than expected among neonates with hypertrypsinaemia. The strategy of screening used here allows to highlight the variability of mutations detected in heterozygotes and to show that severe mutations, as well as mild mutations, have been observed in neonates with hypertrypsinaemia. If there is no doubt that neonatal hypertrypsinaemia is associated with an elevated frequency of carriers, the underlying mechanisms remain obscure.

Neonatal screening for cystic fibrosis in Brittany, France: assessment of 10 years' experience and impact on prenatal diagnosis

BACKGROUND

Neonatal screening for cystic fibrosis has been a subject of debate over the past few years. This study assesses 10 years of neonatal screening in Brittany, France, and examines its impact on prenatal screening of subsequent pregnancies in couples with an affected child.

METHODS

The study included all the neonates screened for cystic fibrosis in Brittany from Jan 1, 1989, to Dec 31, 1998. The screening consisted of an immunoreactive trypsinogen assay from dried blood spots, plus, from 1993, mutation analysis. Data were collected on incidence of cystic fibrosis, and genotypic and biochemical characteristics. The use of prenatal screening of subsequent pregnancies in affected families was also investigated.

FINDINGS

Of the 343,756 neonates screened, 118 children with cystic fibrosis were identified, giving an incidence of one in 2913. All mutated alleles were characterised: 34 different mutations resulting in 36 genotypes were detected. The introduction of DNA analysis into the protocol greatly reduced the recall rate and increased the sensitivity of the test. The mean cost of the screening programme was US$2.32 per screened child. 39 (34%) of the families identified by neonatal screening opted for subsequent prenatal diagnosis at least once. 12 couples would have benefited from this procedure while their first child was still symptom-free. 42 healthy children were born, and 18 pregnancies were terminated (therapeutic abortion rate of 100%).

INTERPRETATION

We have shown the feasibility of neonatal screening for cystic fibrosis in Brittany. Through the detection of a large range of mutations, neonatal screening provides the opportunity for more reliable prenatal diagnosis and cascade screening. The neonatal screening programme described here could provide a good model for other countries intending to initiate such a scheme.

Catecholamine, blood lactate and ventilatory responses to multi-cycle-run blocks

PURPOSE AND METHODS

This study was designed to determine whether the physiological responses elicited during the run part of repeated bouts of cycle-run exercise are similar to those required during the run segment of a cycle-run succession. Thirteen male triathletes underwent four successive laboratory trials: 1) an incremental treadmill test, 2) an incremental cycle test, 3) 30 min of cycling followed by 20 min of running (C-R), and 4) five repeated bouts of 6 min of cycling and 4 min of running (X-CR). During the C-R and X-CR trials, venous blood samples were obtained to measure lactate, epinephrine and norepinephrine concentrations. During all trials, ventilatory data were collected every min using an automated breath-by-breath system.

RESULTS

The results showed that 1) the cardiorespiratory responses observed during running were similar in the X-CR and C-R trials, 2) the lactate concentration was similar in both trials, 3) the epinephrine concentration was greater (277.9 +/- 11.9 vs 169.8 +/- 86.7 pg x mL(-1), P < 0.025) in X-CR than in C-R, and 4) the norepinephrine concentration was similar in both trials, except at the first cycle-run succession (T1) of X-CR.

CONCLUSION

We concluded that 1) multi-block training is a good method to stimulate the specific adaptations required for the cycle-run succession, and particularly for the cycle-run transition, and 2) multi-block training seems to induce a greater catecholaminergic response, which may be due to a combination of an inherent effect of this type of training and the triathletes' relative lack of experience with it. In any case, the efficacy of the multi-block model needs to be more thoroughly evaluated over the course of a longer-term training program.

Prevalence of GBV C/HGV RNA and GBV C/HGV antibodies in French volunteer blood donors: results of a collaborative study

BACKGROUND AND OBJECTIVES

Posttransfusion hepatitis still occurs at an incidence of about 1 in 118,000 for HBV and 1 in 220,000 for HCV. This collaborative study aimed to determine the prevalence of a novel flavivirus, GBV-C/HGV, even though its role in transfusion-associated hepatitis is uncertain.

MATERIALS AND METHODS

GBV-C/HGV RNA was detected by PCR using either the Boehringer detection kit or by primers previously described. HGV antibodies were detected by a serological assay from Boehringer.

RESULTS

The observed GBV-C/HGV RNA frequency was 3.4%. HGV antibodies occurred in 9.5% of donors.

CONCLUSION

In our study, 12. 9% of the donors had been in contact with the GBV-C/HGV virus.