Factors Influencing Adherence to the Risk Management Program for Women With a Genetic Predisposition to Breast Cancer: Real-World Data from a French Multicenter Program

BACKGROUND

Risk management programs targeting women with genetic predispositions to breast cancer (BC), eg, BRCA1 and BRCA2, are effective assuming full adherence with the program protocol. However, high risk to BC in women and equal access to care may not result in high and uniform adherence with the program.

OBJECTIVE

To elucidate factors influencing adherence with screening program in women with genetic predispositions to BC.

MATERIAL AND METHODS

We retrieved data from a multicenter pathogenic-related BC surveillance program across 4 French regions. We used multilevel logistic modeling to analyze factors of adherence with the program, with "on-time" or postponed screening as the dependent variable.

RESULTS

Seven hundred and seventy-eight participants were followed for a 4.7-year median. We observed 2796 annual screening rounds and 5.4% postponed rounds with a 6-month margin. Women with prevalent BC and carriers of BRCA1 and BRCA2 mutations did not have on-time annual screenings any more than women low cancer risk. Better adherence was observed with screenings after the 2nd round, with higher total number of rounds. Having one or more recalls was significantly associated with worse adherence. No contextual factors affected adherence. Furthermore, postponed rounds increased between 2018 and 2020 compared to 2015 and 2017.

CONCLUSION

Having a higher BC risk status does not result in better adherence to the risk management program. However, factors directly related to screening rounds reduced postponements. Future research should address the benefits of screening-related organizational factors that contribute to adherence improvement.

Low risk of embryonic and other cancers in PIK3CA-related overgrowth spectrum: Impact on screening recommendations

The PIK3CA-related overgrowth spectrum (PROS) encompasses various conditions caused by mosaic activating PIK3CA variants. PIK3CA somatic variants are also involved in various cancer types. Some generalized overgrowth syndromes are associated with an increased risk of Wilms tumor (WT). In PROS, abdominal ultrasound surveillance has been advocated to detect WT. We aimed to determine the risk of embryonic and other types of tumors in patients with PROS in order to evaluate surveillance relevance. We searched the clinical charts from 267 PROS patients for the diagnosis of cancer, and reviewed the medical literature for the risk of cancer. In our cohort, six patients developed a cancer (2.2%), and Kaplan Meier analyses estimated cumulative probabilities of cancer occurrence at 45 years of age was 5.6% (95% CI = 1.35%-21.8%). The presence of the PIK3CA variant was only confirmed in two out of four tumor samples. In the literature and our cohort, six cases of Wilms tumor/nephrogenic rests (0.12%) and four cases of other cancers have been reported out of 483 proven PIK3CA patients, in particular the p.(His1047Leu/Arg) variant. The risk of WT in PROS being lower than 5%, this is insufficient evidence to recommend routine abdominal imaging. Long-term follow-up studies are needed to evaluate the risk of other cancer types, as well as the relationship with the extent of tissue mosaicism and the presence or not of the variant in the tumor samples.

Revisiting the historical scenario of a disease dissemination using genetic data and Approximate Bayesian Computation methodology: The case of Pseudocercospora fijiensis invasion in Africa

The reconstruction of geographic and demographic scenarios of dissemination for invasive pathogens of crops is a key step toward improving the management of emerging infectious diseases. Nowadays, the reconstruction of biological invasions typically uses the information of both genetic and historical information to test for different hypotheses of colonization. The Approximate Bayesian Computation framework and its recent Random Forest development (ABC-RF) have been successfully used in evolutionary biology to decipher multiple histories of biological invasions. Yet, for some organisms, typically plant pathogens, historical data may not be reliable notably because of the difficulty to identify the organism and the delay between the introduction and the first mention. We investigated the history of the invasion of Africa by the fungal pathogen of banana Pseudocercospora fijiensis, by testing the historical hypothesis against other plausible hypotheses. We analyzed the genetic structure of eight populations from six eastern and western African countries, using 20 microsatellite markers and tested competing scenarios of population foundation using the ABC-RF methodology. We do find evidence for an invasion front consistent with the historical hypothesis, but also for the existence of another front never mentioned in historical records. We question the historical introduction point of the disease on the continent. Crucially, our results illustrate that even if ABC-RF inferences may sometimes fail to infer a single, well-supported scenario of invasion, they can be helpful in rejecting unlikely scenarios, which can prove much useful to shed light on disease dissemination routes.

Mutation of the proline P81 into a serine modifies the tumour suppressor function of the von Hippel-Lindau gene in the ccRCC

BACKGROUND

The von Hippel-Lindau disease is an autosomal dominant syndrome associated with tumour formation in various tissues, such as retina, central nervous system, kidney, and adrenal glands. VHL gene deletion or mutations support the development of various cancers. Unclassified VHL variants also referred as "of unknown significance" result from gene mutations that have an unknown or unclear effect on protein functions. The P81S mutation has been linked to low penetrance Type 1 disease but its pathogenic function was not clearly determined.

METHODS

We established a stable cell line expressing the pVHL213 (c.241C>T, P81S) mutant. Using biochemical and physiological approaches, we herein analysed pVHL folding, stability and function in the context of this VHL single missense mutation.

RESULTS

The P81S mutation mostly affects the non-canonical function of the pVHL protein. The cells expressing the pVHL213P81S acquire invasive properties in relation with modified architecture network.

CONCLUSION

We demonstrated the pathogenic role of this mutation in tumour development in vhl patients and confirm a medical follow up of family carrying the c.241C>T, P81S.

Minors at risk of von Hippel-Lindau disease: 10 years' experience of predictive genetic testing and follow-up adherence

Von Hippel-Lindau (VHL) disease is one of the most common cancer predisposition syndromes. Penetrance is high with around 20% of children presenting detectable and curable manifestations of the disease at 15 years old. VHL predictive genetic testing (PGT) is recommended during childhood from age 5 years in France. Insufficient compliance to surveillance of VHL pathogenic variant (PV) carriers is associated with severe outcome. PGT experienced by children and their parents is probably critical in influencing future acceptance of the result and adherence to surveillance. We conducted a retrospective study on minors tested (aged 5 to 16 years old) from 2010 to 2020, in a multidisciplinary oncogenetics consultation which follows a 3-step protocol based on psychological familial support. The objectives were to assess the adherence to follow-up within the National Expert Center for inherited predispositions to renal tumors (PREDIR) network of VHL PV carriers and its benefit through tumor detection and medical interventions. A VHL PGT was carried out in 34 children. Among the 16 children diagnosed as VHL PV carriers addressed to the PREDIR network, none had discontinued surveillance after a median of 41 months. Follow-up examinations detected 11 tumors in 6 children, 4 have been surgically treated. All had a favorable outcome. Our data suggest that a specific and adapted procedure for PGT in at-risk VHL children as well as a follow-up, organized within a specialized expert network, fosters a complete adherence to the surveillance protocol and thus lead to a favorable clinical outcome.

Modulation of DNA Methylation/Demethylation Reactions Induced by Nutraceuticals and Pollutants of Exposome Can Promote a C > T Mutation in the Breast Cancer Predisposing Gene PALB2

Background: Deregulation of DNA methylation/demethylation reactions may be the source of C > T mutation via active deamination of 5-methylcytosine to thymine. Exposome, that is to say, the totality of exposures to which an individual is subjected during their life, can deregulate these reactions. Thus, one may wonder whether the exposome can induce C > T mutations in the breast cancer-predisposing gene PALB2. Methods: Our work is based on the exposure of MCF10A mammary epithelial cells to seven compounds of our exposome (folate, Diuron, glyphosate, PFOA, iron, zinc, and ascorbic acid) alone or in cocktail. The qMSRE and RMS techniques were used to study the impact of these exposures on the level of methylation and mutation of the PALB2 gene. Results: Here, we have found that exposome compounds (nutriments, ions, pollutants) promoting the cytosine methylation and the 5-methylcytosine deamination have the ability to promote a specific C > T mutation in the PALB2 gene. Interestingly, we also noted that the addition of exposome compounds promoting the TET-mediated conversion of 5-methylcytosine (Ascorbic acid and iron) abrogates the presence of C > T mutation in the PALB2 gene. Conclusions: Our study provides a proof of concept supporting the idea that exposomes can generate genetic mutation by affecting DNA methylation/demethylation.

Classification of 101 BRCA1 and BRCA2 variants of uncertain significance by cosegregation study: A powerful approach

Up to 80% of BRCA1 and BRCA2 genetic variants remain of uncertain clinical significance (VUSs). Only variants classified as pathogenic or likely pathogenic can guide breast and ovarian cancer prevention measures and treatment by PARP inhibitors. We report the first results of the ongoing French national COVAR (cosegregation variant) study, the aim of which is to classify BRCA1/2 VUSs. The classification method was a multifactorial model combining different associations between VUSs and cancer, including cosegregation data. At this time, among the 653 variants selected, 101 (15%) distinct variants shared by 1,624 families were classified as pathogenic/likely pathogenic or benign/likely benign by the COVAR study. Sixty-six of the 101 (65%) variants classified by COVAR would have remained VUSs without cosegregation data. Of note, among the 34 variants classified as pathogenic by COVAR, 16 remained VUSs or likely pathogenic when following the ACMG/AMP variant classification guidelines. Although the initiation and organization of cosegregation analyses require a considerable effort, the growing number of available genetic tests results in an increasing number of families sharing a particular variant, and thereby increases the power of such analyses. Here we demonstrate that variant cosegregation analyses are a powerful tool for the classification of variants in the BRCA1/2 breast-ovarian cancer predisposition genes.

Osteosarcoma without prior retinoblastoma related to RB1 low-penetrance germline pathogenic variants: A novel type of RB1-related hereditary predisposition syndrome?

Background

Retinoblastoma (Rb) is a rare intraocular malignant tumor in children with high overall survival. Predisposition to Rb is linked to RB1 germline mutations with high penetrance, but rare RB1 low‐penetrance variants are also known. Rb survivors are at risk of second primary malignancies (SPMs), mostly osteosarcoma and soft‐tissue sarcoma. Nevertheless, the risk of primary osteosarcoma developing without prior Rb has not been reported in RB1 germline mutation carriers.

Methods

We report a patient in whom osteosarcoma developed at age 17 as a first primary malignancy within a family context of sarcoma.

Results

Unexpectedly, genetic testing identified a low‐penetrance germline mutation in RB1 [NM_000321.2: c.45_76dup; p.(Pro26Leufs*50)]. In eight additional similar cases from published and unpublished reports of families, first primary osteosarcomas and sarcomas mostly developed in RB1 low‐penetrance mutation carriers without prior Rb.

Conclusion

We propose that first primary sarcoma and osteosarcoma could be a novel clinical presentation of a RB1‐related hereditary predisposition syndrome linked to RB1 low‐penetrance germline mutations. In these families, careful screening of primary non‐Rb cancer and SPMs is required by maintaining enhanced clinical vigilance. Implementing lifelong periodic whole‐body MRI screening might be a complementary strategy for unaffected carrier relatives in these families.

Dermatological manifestations in Noonan syndrome: a prospective multicentric study of 129 patients positive for mutation

BACKGROUND

Data on dermatological manifestations of Noonan syndrome (NS) remain heterogeneous and are based on limited dermatological expertise.

OBJECTIVES

To describe the dermatological manifestations of NS, compare them with the literature findings, and test for dermatological phenotype-genotype correlations with or without the presence of PTPN11 mutations.

METHODS

We performed a large 4-year, prospective, multicentric, collaborative dermatological and genetic study.

RESULTS

Overall, 129 patients with NS were enrolled, including 65 patients with PTPN11-NS, 34 patients with PTPN11-NS with multiple lentigines (NSML), and 30 patients with NS who had a mutation other than PTPN11. Easy bruising was the most frequent dermatological finding in PTPN11-NS, present in 53·8% of patients. Multiple lentigines and café-au-lait macules (n ≥ 3) were present in 94% and 80% of cases of NSML linked to specific mutations of PTPN11, respectively. Atypical forms of NSML could be associated with NS with RAF1 or NRAS mutations. In univariate analysis, patients without a PTPN11 mutation showed (i) a significantly higher frequency of keratinization disorders (P = 0·001), including keratosis pilaris (P = 0·005), ulerythema ophryogenes (P = 0·0001) and palmar and/or plantar hyperkeratosis (P = 0·06, trend association), and (ii) a significantly higher frequency of scarce scalp hair (P = 0·035) and scarce or absent eyelashes (P = 0·06, trend association) than those with PTPN11 mutations.

CONCLUSIONS

The cutaneous phenotype of NS with a PTPN11 mutation is generally mild and nonspecific, whereas the absence of a PTPN11 mutation is associated with a high frequency of keratinization disorders and hair abnormalities.

Dermatological manifestations in cardiofaciocutaneous syndrome: a prospective multicentric study of 45 mutation-positive patients

BACKGROUND

Data on dermatological manifestations of cardiofaciocutaneous syndrome (CFCS) remain heterogeneous and almost without expert dermatological classification.

OBJECTIVES

To describe the dermatological manifestations of CFCS; to compare them with the literature findings; to assess those discriminating CFCS from other RASopathies, including Noonan syndrome (NS) and Costello syndrome (CS); and to test for dermatological phenotype-genotype correlations.

METHODS

We performed a 4-year, large, prospective, multicentric, collaborative dermatological and genetic study.

RESULTS

Forty-five patients were enrolled. Hair abnormalities were ubiquitous, including scarcity or absence of eyebrows and wavy or curly hair in 73% and 69% of patients, respectively. Keratosis pilaris (KP), ulerythema ophryogenes (UO), palmoplantar hyperkeratosis (PPHK) and multiple melanocytic naevi (MMN; over 50 naevi) were noted in 82%, 44%, 27% and 29% of patients, respectively. Scarcity or absence of eyebrows, association of UO and PPHK, diffuse KP and MMN best differentiated CFCS from NS and CS. Oral acitretin may be highly beneficial for therapeutic management of PPHK, whereas treatment of UO by topical sirolimus 1% failed. No significant dermatological phenotype-genotype correlation was determined.

CONCLUSIONS

A thorough knowledge of CFCS skin manifestations would help in making a positive diagnosis and differentiating CFCS from CS and NS.

Contribution of germline deleterious variants in the RAD51 paralogs to breast and ovarian cancers

RAD51 paralogs (RAD51B, RAD51C, RAD51D, XRCC2, and XRCC3) have recently been involved in breast and ovarian cancer predisposition: RAD51B, RAD51C, and RAD51D in ovarian cancer, RAD51B and XRCC2 in breast cancer. The aim of this study was to estimate the contribution of deleterious variants in the five RAD51 paralogs to breast and ovarian cancers. The five RAD51 paralog genes were analyzed by next-generation sequencing technologies in germline DNA from 2649 consecutive patients diagnosed with breast and/or ovarian cancer. Twenty-one different deleterious variants were identified in the RAD51 paralogs in 30 patients: RAD51B (n = 4), RAD51C (n = 12), RAD51D (n = 7), XRCC2 (n = 2), and XRCC3 (n = 5). The overall deleterious variant rate was 1.13% (95% confidence interval (CI): 0.72-1.55%) (30/2649), including 15 variants in breast cancer only cases (15/2063; 0.73% (95% CI: 0.34-1.11%)) and 15 variants in cases with at least one ovarian cancer (15/570; 2.63% (95% CI: 1.24-4.02%)). This study is the first evaluation of the five RAD51 paralogs in breast and ovarian cancer predisposition and it demonstrates that deleterious variants can be present in breast cancer only cases. Moreover, this is the first time that XRCC3 deleterious variants have been identified in breast and ovarian cancer cases.

Botulinum neurotoxin injection for the treatment of epiphora in nasolacrimal duct obstruction

PURPOSE

Retrospective long-term study to evaluate the efficacy of botulinum neurotoxin A (BoNT/A) therapy for epiphora due to non-surgical nasolacrimal duct obstruction.

INTRODUCTION

BoNT/A has been used successfully since 2000 in axillary hyperhidrosis to reduce secretory disorders. Some isolated cases of hyperlacrimation or crocodile tear syndrome have been treated on this basis. We used BoNT/A to decrease lacrimal secretion in cases of epiphora.

METHODS

We reviewed the qualitative and quantitative degree of improvement of epiphora after botulinum neurotoxin injections in the palpebral lobe of the lacrimal gland, carried out in an ophthalmic centre between 2009 and 2016. Epiphora was graded using a questionnaire, Munk scores and Schirmer tests before and after injections. Severity of side effects was recorded.

RESULTS

Twenty-seven palpebral lacrimal glands of twenty patients with epiphora, mean age 65±13, were treated with BoNT/A (Botox^® or Xeomin^®) from April 2009 to April 2016. The epiphora was induced by persistent nasolacrimal duct stenosis after surgical treatment. No conventional medical nor surgical treatment was effective at this time. The technique of injection, dilution and dosage were specific. We re-injected 14/27 cases on an as-needed basis, 7/27 cases three times, 3/27 cases four times, and 2/27 cases (same patient both glands) five times. The Schirmer test measured a decrease of lacrimal secretion in 24/27 (89%) lacrimal glands after neurotoxin injection. Side effects were ptosis in 4 cases and transient esotropia in 2 cases. The authors describe the injection techniques, the dosage, the volume and concentration of BoNT/A.

CONCLUSION

Patients with epiphora can be treated effectively with BoNT/A to reduce lacrimal secretion of the principal lacrimal gland in its palpebral portion. Ninety percent of the patients were very satisfied, with few side effects (ptosis or mild diplopia lasting from 3 days to 3 weeks). More studies are needed to delineate which types of epiphora can be treated with BoNT/A.

Otopalatodigital spectrum disorders: refinement of the phenotypic and mutational spectrum

Otopalatodigital spectrum disorders (OPDSD) constitute a group of dominant X-linked osteochondrodysplasias including four syndromes: otopalatodigital syndromes type 1 and type 2 (OPD1 and OPD2), frontometaphyseal dysplasia, and Melnick-Needles syndrome. These syndromes variably associate specific facial and extremities features, hearing loss, cleft palate, skeletal dysplasia and several malformations, and show important clinical overlap over the different entities. FLNA gain-of-function mutations were identified in these conditions. FLNA encodes filamin A, a scaffolding actin-binding protein. Here, we report phenotypic descriptions and molecular results of FLNA analysis in a large series of 27 probands hypothesized to be affected by OPDSD. We identified 11 different missense mutations in 15 unrelated probands (n=15/27, 56%), of which seven were novel, including one of unknown significance. Segregation analyses within families made possible investigating 20 additional relatives carrying a mutation. This series allows refining the phenotypic and mutational spectrum of FLNA mutations causing OPDSD, and providing suggestions to avoid the overdiagnosis of OPD1.

Clinical relevance of 8q23, 15q13 and 18q21 SNP genotyping to evaluate colorectal cancer risk

To determine if the at-risk single-nucleotide polymorphism (SNP) alleles for colorectal cancer (CRC) could contribute to clinical situations suggestive of an increased genetic risk for CRC, we performed a prospective national case–control study based on highly selected patients (CRC in two first-degree relatives, one before 61 years of age; or CRC diagnosed before 51 years of age; or multiple primary CRCs, the first before 61 years of age; exclusion of Lynch syndrome and polyposes) and controls without personal or familial history of CRC. SNPs were genotyped using SNaPshot, and statistical analyses were performed using Pearson's χ² test, Cochran–Armitage test of trend and logistic regression. We included 1029 patients and 350 controls. We confirmed the association of CRC risk with four SNPs, with odds ratio (OR) higher than previously reported: rs16892766 on 8q23.3 (OR: 1.88, 95% confidence interval (CI): 1.30–2.72; P=0.0007); rs4779584 on 15q13.3 (OR: 1.42, CI: 1.11–1.83; P=0.0061) and rs4939827 and rs58920878/Novel 1 on 18q21.1 (OR: 1.49, CI: 1.13–1.98; P=0.007 and OR: 1.49, CI: 1.14–1.95; P=0.0035). We found a significant (P<0.0001) cumulative effect of the at-risk alleles or genotypes with OR at 1.62 (CI: 1.10–2.37), 2.09 (CI: 1.43–3.07), 2.87 (CI: 1.76–4.70) and 3.88 (CI: 1.72–8.76) for 1, 2, 3 and at least 4 at-risk alleles, respectively, and OR at 1.71 (CI: 1.18–2.46), 2.29 (CI: 1.55–3.38) and 6.21 (CI: 2.67–14.42) for 1, 2 and 3 at-risk genotypes, respectively. Combination of SNPs may therefore explain a fraction of clinical situations suggestive of an increased risk for CRC.

[Breast and ovarian cancer due to BRCA1&2 hereditary cancer predisposition syndrome and reproduction: literature review]

INTRODUCTION

Germline mutations BRCA1&2 are responsible in women for breast and ovarian cancers that commonly occur at a young age: as such, there are strong interactions between the oncological risks and the events of reproductive life, pregnancy, breastfeeding, and management of infertility.

MATERIALS AND METHODS

A review of the international literature from the PubMed database was conducted, and recommendations of French health agencies were exposed. Published studies are case-control and cohort studies in the majority, with a low level of evidence.

RESULTS

Pregnancy and lactation have no effect on breast and ovaries or even decreases the risk. The sex ratio among patients carrying the mutation is in favor of girls. It is not observed more infertility in patients carrying a mutation despite a strong suspicion of premature ovarian failure, and infertility treatments do not increase breast and ovarian risk. There are ethical debates concerning the place of pre-natal diagnosis: both experts and concerned patients recommend a case-by-case analysis of the requests.

Contrasting introduction scenarios among continents in the worldwide invasion of the banana fungal pathogen Mycosphaerella fijiensis

Reconstructing and characterizing introduction routes is a key step towards understanding the ecological and evolutionary factors underlying successful invasions and disease emergence. Here, we aimed to decipher scenarios of introduction and stochastic demographic events associated with the global spread of an emerging disease of bananas caused by the destructive fungal pathogen Mycosphaerella fijiensis. We analysed the worldwide population structure of this fungus using 21 microsatellites and 8 sequence-based markers on 735 individuals from 37 countries. Our analyses designated South-East Asia as the source of the global invasion and supported the location of the centre of origin of M. fijiensis within this area. We confirmed the occurrence of bottlenecks upon introduction into other continents followed by widespread founder events within continents. Furthermore, this study suggested contrasting introduction scenarios of the pathogen between the African and American continents. While potential signatures of admixture resulting from multiple introductions were detected in America, all the African samples examined seem to descend from a single successful founder event. In combination with historical information, our study reveals an original and unprecedented global scenario of invasion for this recently emerging disease caused by a wind-dispersed pathogen.

Non-USH2A mutations in USH2 patients

We have systematically analyzed the two known minor genes involved in Usher syndrome type 2, DFNB31 and GPR98, for mutations in a cohort of 31 patients not linked to USH2A. PDZD7, an Usher syndrome type 2 (USH2) related gene, was analyzed when indicated. We found that mutations in GPR98 contribute significantly to USH2. We report 17 mutations in 10 individuals, doubling the number of GPR98 mutations reported to date. In contrast to mutations in usherin, the mutational spectrum of GPR98 predominantly results in a truncated protein product. This is true even when the mutation affects splicing, and we have incorporated a splicing reporter minigene assay to show this, where appropriate. Only two mutations were found which we believe to be genuine missense changes. Discrepancy in the mutational spectrum between GPR98 and USH2A is discussed. Only two patients were found with mutations in DFNB31, showing that mutations of this gene contribute to only a very small extent to USH2. Close examination of the clinical details, where available, for patients in whom no mutation was found in USH2A, GPR98, or DFNB31, showed that most of them had atypical features. In effect, these three genes account for the vast majority of USH2 patients and their analysis provide a robust pathway for routine molecular diagnosis.

Usher syndrome type 2 caused by activation of an USH2A pseudoexon: implications for diagnosis and therapy

USH2A sequencing in three affected members of a large family, referred for the recessive USH2 syndrome, identified a single pathogenic alteration in one of them and a different mutation in the two affected nieces. As the patients carried a common USH2A haplotype, they likely shared a mutation not found by standard sequencing techniques. Analysis of RNA from nasal cells in one affected individual identified an additional pseudoexon (PE) resulting from a deep intronic mutation. This was confirmed by minigene assay. This is the first example in Usher syndrome (USH) with a mutation causing activation of a PE. The finding of this alteration in eight other individuals of mixed European origin emphasizes the importance of including RNA analysis in a comprehensive diagnostic service. Finally, this mutation, which would not have been found by whole-exome sequencing, could offer, for the first time in USH, the possibility of therapeutic correction by antisense oligonucleotides (AONs).

Audiological findings in 100 USH2 patients

Bilateral sensorineural hearing loss (HL), classically described as mild to severe with a typically down-sloping audiometric configuration, is the earliest symptom occurring in Usher syndrome type II (USH2). Audiological findings were analyzed in a total of 100 USH2 patients (92 families) divided into three groups according to the gene involved: 88 USH2A, 10 GPR98 and 2 DFNB31 patients. A fine analysis of audiograms was performed (pure tone average, degree of severity, configuration). The median age of HL diagnosis was 5 years (range 8 months-31 years) although the median age at USH2 diagnosis was 34.5 (range 8-76). Moderate HL was predominant (76%) and a gently down-sloping configuration characterized most audiograms (66%). No statistically significant difference was found between USH2A and GPR98 patients but a tendency was clearly noted for more GPR98 patients to present with severe hearing loss. It is not possible to predict the mutated gene from audiograms.

First Report of Black Sigatoka Disease in Banana Caused by Mycosphaerella fijiensis on Martinique Island

Mycosphaerella fijiensis Morelet (anamorph Pseudocercospora fijiensis Morelet), the causal agent of black Sigatoka disease of banana, is considered to be the greatest economical threat for export-banana cultivation throughout the world because most cultivars are highly susceptible. The disease has a worldwide distribution throughout the humid tropical regions, but was still absent in some Caribbean islands hitherto. In Martinique Island, an intensive survey has been conducted by the plant protection service and the Fédération Régionale de Défense Contre les Organismes Nuisibles (FREDON) since April 2008 to detect as early as possible any outbreak of infection by M. fijiensis. In September 2010, typical symptoms of black Sigatoka were observed in a plantain crop located in Ducos Municipality (14°35.702'N, 60°58.221'W) in the west-central area of the island. Typical early symptoms were 1- to 4-mm long brown streaks on the abaxial leaf surface. The presence of the disease was further confirmed by the in situ observation of microscopic features of the anamorphic form of the pathogen (3). Typical pale brown, straight or slightly geniculate conidiophores were observed occurring singly or in little groups without any stroma, with a thickened wall at the conidial scars. Conidia were hyaline to pale olive, straight or slightly curved, with one to eight septa, and a conspicuous scar at the basal cell. The diagnosis was confirmed by real-time PCR targeting M. fijiensis-specific regions within the β-tubulin gene (1). Positive results were consistently obtained with DNA extracted from infected banana tissue samples, and the identity of the amplicon was confirmed by sequencing (Accession No. HQ412771) and comparison with reference sequences deposited on GenBank. After this first finding, the survey was intensified and black Sigatoka symptoms were also observed in several other locations on the island, affecting a large range of susceptible cultivars (Grande Naine, French, and Figue Sucrée), and in plantations, backyards, and private gardens. The presence of the fungus in the samples was confirmed by PCR analysis of DNA extracted from symptomatic leaves with a M. fijiensis-specific ITS-based primer pair (2). The pathogen may have been introduced into Martinique by ascospores, from islands where black Sigatoka is present, that were blown by continuous southerly winds over a 2-week period in August 2010 that was immediately followed by heavy rains that favor disease development. To our knowledge, this is the first report of M. fijiensis on Martinique Island, showing that the disease is still spreading northward in this region of the Caribbean. References: (1) M. Arzanlou et al. Phytopathology 97:1112, 2007. (2) J. Henderson et al. Page 59 in: Mycosphaerella Leaf Spot Disease of Bananas: Present Status and Outlook. L. Jacome et al., eds. International Network for the Improvement of Banana and Plantain (INIBAP), Montpellier, France. 2003. (3) M. F. Zapater et al. Fruits 63:389, 2008.

Ex vivo splicing assays of mutations at noncanonical positions of splice sites in USHER genes

Molecular diagnosis in Usher syndrome type 1 and 2 patients led to the identification of 21 sequence variations located in noncanonical positions of splice sites in MYO7A, CDH23, USH1C, and USH2A genes. To establish experimentally the splicing pattern of these substitutions, whose impact on splicing is not always predictable by available softwares, ex vivo splicing assays were performed. The branch-point mapping strategy was also used to investigate further a putative branch-point mutation in USH2A intron 43. Aberrant splicing was demonstrated for 16 of the 21 (76.2%) tested sequence variations. The mutations resulted more frequently in activation of a nearby cryptic splice site or use of a de novo splice site than exon skipping (37.5%). This study allowed the reclassification as splicing mutations of one silent (c.7872G>A (p.Glu2624Glu) in CDH23) and four missense mutations (c.2993G>A (p.Arg998Lys) in USH2A, c.592G>A (p.Ala198Thr), c.3503G>C [p.Arg1168Pro], c.5944G>A (p.Gly1982Arg) in MYO7A), whereas it provided clues about a role in structure/function in four other cases: c.802G>A (p.Gly268Arg), c.653T>A (p.Val218Glu) (USH2A), and c.397C>T (p.His133Tyr), c.3502C>T (p.Arg1168Trp) (MYO7A). Our data provide insights into the contribution of splicing mutations in Usher genes and illustrate the need to define accurately their splicing outcome for diagnostic purposes.

Genetic discontinuities and disequilibria in recently established populations of the plant pathogenic fungus Mycosphaerella fijiensis

Dispersal processes of fungal plant pathogens can be inferred from analysis of spatial genetic structures resulting from recent range expansion. The relative importance of long-distance dispersal (LDD) events vs. gradual dispersal in shaping population structures depends on the geographical scale considered. The fungus Mycosphaerella fijiensis, pathogenic on banana, is an example of a recent worldwide epidemic. Founder effects in this species were detected at both global and continental scale, suggesting stochastic spread of the disease through LDD events. In this study, we analysed the structure of M. fijiensis populations in two recently (∼1979-1980) colonized areas in Costa Rica and Cameroon. Isolates collected in 10-15 sites distributed along a ∼250- to 300- km-long transect in each country were analysed using 19 microsatellite markers. We detected low-to-moderate genetic differentiation among populations in both countries and isolation by distance in Cameroon. Combined with historical data, these observations suggest continuous range expansion at the scale of banana-production area through gradual dispersal of spores. However, both countries displayed specific additional signatures of colonization: a sharp discontinuity in gene frequencies was observed along the Cameroon transect, while the Costa Rican populations seemed not yet to have reached genetic equilibrium. These differences in the genetic characteristics of M. fijiensis populations in two recently colonized areas are discussed in the light of historical data on disease spread and ecological data on landscape features.

Regulation of CYP4A expression by bezafibrate in primary culture of rat and human hepatocytes: interspecies difference and influence of N-acetylcysteine

The effects of fibrates on cytochrome P450 4A (CYP4A) expression have not been clearly evaluated in human hepatocytes, human being reported as a non-responsive species. We have evaluated the effects of clofibrate, bezafibrate (BEZA), WY-14643, nafenopin and ciprofibrate at the concentration of 250 microM on CYP4A expression in primary cultures of rat and human hepatocytes. BEZA greatly induced mRNA expression in both species. Eight out of 10 human cultures responded to BEZA 250 microM. CYP4A-dependent activity was increased in rat, but not in human hepatocytes. The antioxidant N-acetylcysteine (Nac) enhanced the inducing effect of BEZA on mRNA expression, this potentialization being higher in human compared to rat hepatocytes. By contrast, Nac decreased the inducing effect of BEZA on CYP4A-dependent activity in rat and had either no effect or decreased the activity in BEZA-treated human hepatocytes. In conclusion, the cellular environment appears as an important parameter to take into account when studying CYP4A induction and could partly explain interspecies differences in the complex regulation of CYP4A expression.

Comparison of clearance predictions using primary cultures and suspensions of human hepatocytes

Various incubation conditions of human hepatocytes were compared for their accuracy in predicting the in vivo hepatic clearance (CL(H)) of model compounds. The test compounds were the highly cleared, low protein bound naloxone (in vivo CL(H) = 25 ml min(-1) kg(-1); free fraction = 0.6), the medium clearance, highly protein bound midazolam (CL(H) = 12 ml min(-1) kg(-1); free fraction = 0.04) and the low clearance, highly protein bound bosentan (CL(H) = 3.9 ml min(-1) kg(-1); free fraction = 0.02). Each compound was tested in three 'hepatocyte systems', using resections from three donors, in the presence and absence of human serum. Those hepatocyte systems were: conventional primary cultures, freshly isolated suspensions and cryopreserved suspended hepatocytes. Except for a twofold overestimated CL(H) for bosentan from conventional primary cultures, and despite variable cryopreservation recoveries, similar predictions of CL(H) were recorded with all hepatocyte systems. Moreover, the CL(H) values obtained with cryopreserved suspended hepatocytes were similar to those obtained with freshly isolated suspensions. For midazolam and bosentan, the predicted in vivo CL(H) was markedly higher in the presence of serum, whereas serum had little influence on the scaled-up CL(H) of naloxone. In vivo, CL(H) was properly approached for naloxone and bosentan (particularly from experiments in the presence of serum), but it was strongly underestimated for midazolam (particularly in the absence of serum). Additional compounds need to be investigated to confirm the above findings as well as to assess why the clearances of some highly protein-bound compounds are still considerably underestimated.

Differential inhibition of rat and human hepatic cytochrome P450 by Andrographis paniculata extract and andrographolide

The inhibitory effect of Andrographis paniculata extract (APE) and andrographolide (AND), the most medicinally active phytochemical in the extract, on hepatic cytochrome P450s (CYPs) activities was examined using rat and human liver microsomes. For this purpose, CYP1A2-dependent ethoxyresorufin-O-deethylation, CYP2B1-dependent benzyloxyresorufin-O-dealkylation, CYP2B6-dependent bupropion hydroxylation, CYP2C-dependent tolbutamide hydroxylation, CYP2E1-dependent p-nitrophenol hydroxylation and CYP3A-dependent testosterone 6 beta-hydroxylation activities, were determined in the presence and absence of APE or AND (0-200 microM). APE inhibited ethoxyresorufin-O-deethylation activity in rat and human liver microsomes, with apparent Ki values of 8.85 and 24.46 microM, respectively. In each case, the mode of inhibition was noncompetitive. APE also inhibited tolbutamide hydroxylation both in rat and human microsomes with apparent Ki values of 8.21 and 7.51 microM, respectively and the mode of inhibition was mixed type. In addition, APE showed a competitive inhibition only on CYP3A4 in human microsomes with Ki of 25.43 microM. AND was found to be a weak inhibitor of rat CYP2E1 with a Ki of 61.1 microM but did not affect human CYP2E1. In conclusion, it cannot be excluded from the present study that APE could cause drug-drug interactions in humans through CYP3A and 2C9 inhibition.

Vitamin E analogues reduce the incidence of ventricular fibrillations and scavenge free radicals

The aim of our study was to analyse the protective effects of different alpha-tocopherol analogues 1) against fibrillations induced by an ischemia-reperfusion sequence, and 2) to further investigate in vitro the radical scavenging properties of these analogues by two sensitive methods. Concerning 1: isolated rat hearts underwent 10 min of coronary ligation followed by reperfusion and the alpha-tocopherol analogues were infused 15 min before occlusion. Functional parameters including heart rate and fibrillations were recorded. Concerning 2: the beta-phycoerythrin assay was utilised to determine the oxygen radical absorbing capacity (ORAC) of these vitamin E analogues against peroxyl radicals. Electron paramagnetic resonance (EPR) was used to measure their scavenger abilities on hydroxyl radical and superoxide anion production. Concerning 1: ventricular fibrillation times were reduced for all analogues treated hearts at concentrations of 1 microM and 5 microM, with Trolox being the most efficacious. Concerning 2: in our experimental conditions of intense production of free radicals, scavenging IC50 values for hydroxyl radical were 1.15, 2.17 and 4.04 mM for Trolox, MDL 74270 and MDL 74366 respectively. Superoxide anion IC50 values were 1.0 and 6.75 mM for Trolox and MDL 74270. Our results show that water-soluble analogues of vitamin E are effective in the prevention of coronary ligation induced reperfusion arrhythmia, under our experimental conditions. Moreover, our data demonstrate that these vitamin E analogues are effective scavengers for a variety of radicals. Our studies support the view that compounds that can either inhibit the formation or scavenge free radicals can protect the heart against arrhythmia associated with ischemia-reperfusion.

Demonstration of the production of oxygen-centered free radicals during electrolysis using E.S.R. spin-trapping techniques: effects on cardiac function in the isolated rat heart

The present study was designed to identify the free radicals generated during the electrolysis of the solution used to perfuse isolated rat heart Langendorff preparations. The high reactivity and very short half-life of oxygen free radicals make their detection and identification difficult. A diamagnetic organic molecule (spin trap) can be used to react with a specific radical to produce a more stable secondary radical or "spin adduct" detected by electron spin resonance (ESR). Isovolumic left ventricular systolic pressure (LVSP) and left ventricular end diastolic pressure (LVEDP) were measured by a fluid-filled latex balloon inserted into the left ventricle. The coronary flow was measured by effluent collection. Electrolysis was performed with constant currents of 0.5, 1, 1.5, 3, 5, 7.5, and 10 mA generated by a Grass stimulator and applied to the perfusion solution for 1 min. A group of experiments was done using a 1.5 mA current and a Krebs-Henseleit (K-H) solution containing free radical scavengers (superoxide dismutase (SOD): 100 IU/ml or mannitol: 50 mM). Heart function rapidly declined in hearts perfused with K-H buffer that had been electrolyzed for 1 min. The addition of mannitol (50 mM) to the perfusion solution had no effect on baseline cardiac function before electrolysis while SOD (100 IU/ml) increased the coronary flow. However, SOD was more effective than the mannitol in protecting the heart against decreased of cardiac function, 5 min after the end of electrolysis. Samples of the K-H medium subjected to electrolysis were collected in cuvettes containing a final concentration of 125 mM 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) and analyzed by spectroscopy. The ESR spectrum consisted of a quartet signal (hyperfine couplings aN = aH = 14.9 G) originating from the hydroxyl adduct signal, DMPO-OH. The intensity of the DMPO-OH signal remained stable during the 60 s of electrolysis and the quantity of free radicals induced by electrolysis was directly proportional to the intensity of the current. The addition of mannitol and SOD to the perfusate scavenged the hydroxyl radicals present in the solution, suggesting that both hydroxyl and superoxide radicals were formed during electrolysis.

Beneficial actions of preconditioning and stretch on postischemic contractile function of isolated working rat heart: effects of staurosporine

Preconditioning is commonly induced by a brief ischemic insult; myocardial stretch can trigger this protection by an unknown mechanism. Myocardial stretch preconditions the in vivo canine heart; however, the existence of a stretch-induced protection in the rat heart remains unknown. The purpose of this study was to test this myocardial protection induced, in isolated working rat heart, by global ischemia and stretch initiated by a transient increase in the left ventricle (LV). Isolated rat hearts underwent 30 min of global ischemia followed by 30 min of reperfusion. Before this, hearts received a 15-min period of either no intervention (control; C), 5 min of global ischemia + 10 min of reperfusion (preconditioning; PC) or 5 min of stretch + 10 min with no intervention (stretch; S). Stretch was induced by a transient increase in LV preload from 5 to 20 cm H2O. LV work started under a afterload of 80 cm H2O. Control, PC, and S hearts received either no drug (untreated) or staurosporine (50 nM), a protein kinase C inhibitor, before the "preconditioning" period. Creatine kinase (CK) release, ventricular fibrillation during reperfusion, and postischemic recovery of contractile function (aortic flow) were the end points of the study. In the S group, the abrupt increase in preload resulted in a significant increase of aortic flow (42 +/- 2 to 47 +/- 2 ml/min; p < 0.05). During the 30-min reperfusion period, control hearts displayed a poor recovery of contractile functions (8 +/- 3 ml/min, 30 min after reflow, versus 40 +/- 2 ml/min at baseline; p < 0.05). Both untreated PC and S groups exhibited a significant reduction in CK release, incidence of ventricular fibrillation (55% of control hearts developed persistent VF vs. 6% in both the PC and S groups), and postischemic dysfunction during reperfusion (p < 0.05 vs. control). Staurosporine prevented these beneficial effects in PC and S groups. Our study suggests that myocardial protection can be induced by stretch in the isolated working rat heart, likely through activation of protein kinase C. In conclusion, our results show that ischemic preconditioning and stretch had comparable favorable effect on functional recovery after a sustained ischemic insult in the isolated rat heart.

Interleukin-1 beta and tumor necrosis factor-alpha inhibit the release of [3H]-noradrenaline from isolated human atrial appendages

In the present study, we have investigated the ability of human recombinant interleukin-1 beta (hIL-1 beta) and human recombinant tumor necrosis factor-alpha (hTNF-alpha) to modulate the stimulation-induced (S-I) outflow of [3H]-noradrenaline ([3H]-NA) from isolated superfused human atria. Pieces of human right atrial appendages were excised during routine cardiac surgery. Tissues were incubated with [3H]-NA (0.2 mumol/l) for 30 min at 37 degrees C, then inserted in a Brandel suprafusion system where the radioactivity was washed for 75 min with a Krebs-Henseleit solution at a rate of 0.4 ml/min. Thereafter, the effluent was collected for the remainder of the protocol during which two trains of electrical stimulation (50 mA intensity, 5 Hz frequency, 60 s duration, 2 ms pulses) were delivered at 10 min and 45 min (short protocol) or 85 min (long protocol). The effect of drugs on the S-I outflow of [3H]-NA was determined by adding drugs 20 min (short protocol) or 60 min (long protocol) before the second stimulation. Experiments were carried out in the continuous presence of desipramine (1 mumol/l) to prevent neuronal NA reuptake. The results showed that in human atrium, hIL-1 beta (3 ng/ml) and hTNF-alpha (0.5 ng/ml) significantly inhibited the S-I release of [3H]-NA. The inhibitory effect of hIL-1 beta was blocked by human recombinant IL-1 receptor antagonist (50 ng/ml), and by the cyclooxygenase inhibitor, diclofenac (1 mumol/l), suggesting that hIL-1 beta inhibited NA release through the formation of prostaglandins. The ability of hIL-1 beta and hTNF-alpha to inhibit NA release suggest that mediators of the immune system produced locally may modulate the activity of the sympathetic nervous system in human atrial appendages.

Modulation of noradrenaline release from isolated human atrial appendages

Prejunctional modulation of noradrenaline release has been studied extensively in various experimental preparations. However, the presence and importance of prejunctional noradrenaline release modulation in human cardiac tissue is still unclear. In this study, we have used superfused human right atrial appendages excised from patients undergoing open heart surgery. The tissues were cut into six pieces and incubated with [3H]noradrenaline (4 microCi/ml. 0.2 microM) for 30 min at 37 degrees C. The tissues were then inserted into a suprafusion system and washed for 75 min with a Krebs-Henseleit solution at a rate of 0.4 ml/min. The experimental protocol consisted of a 60-min perfusion period during which a field stimulation (2 ms pulses, 60 s. 50 mA, 5 Hz) was delivered at 10 and 45 min. The effect of the drugs on the stimulation-induced outflow of radioactivity was determined by adding them 20 min before the second stimulation. Each experiment was carried out with or without desipramine (1 microM) to study the influence of the reuptake blockade. Fenoterol (1-1000 nM), a beta 2-adrenoceptor agonist, and angiotensin II (1-1000 nM) significantly increased noradrenaline release in a concentration-dependent manner. The administration of arecaidine propargyl ester (0.03-3 microM), a non-specific muscarinic receptor agonist, and propylnorapomorphine (0.1 nM-1 microM), a DA2-dopaminergic agonist, produced a concentration-dependent inhibition of the stimulation-induced outflow of radioactivity. The alpha 2-adrenoceptor agonist, oxymetazoline (1 microM) inhibited noradrenaline release at a stimulation frequency of 2 Hz, but not at 5 and 10 Hz. The alpha 2-adrenoceptor antagonist, idazoxan (1 microM), significantly increased the release of noradrenaline at 2 and 5 Hz but not at 10 Hz. The results obtained in the present study demonstrated the presence of the facilitatory beta 2-adrenoceptor and angiotensin II receptor as well as the presence of inhibitory alpha 2-adrenoceptor, muscarinic and DA2-dopamine receptors in the human atrial appendage.

Interleukin-1 beta and tumor necrosis factor-alpha inhibit the release of [3H]-noradrenaline from mice isolated atria

In the present study, we have investigated the ability of four cytokines, interleukin-1 beta, interleukin-2, interleukin-6 and tumor necrosis factor-alpha, to modulate the stimulation-induced outflow of radioactivity from isolated superfused mouse atria which where pre-incubated with [3H]-noradrenaline. The tissues were subjected twice to field stimulation (5 Hz frequency, 50 mA intensity, 2 ms pulses for 60 s) and the drugs were added prior to the second stimulation in order to assess their modulatory effects. The results show that mouse recombinant interleukin-1 beta and tumor necrosis factor-alpha inhibited the stimulation-induced release of radioactivity from the isolated mouse atria. The effect of interleukin-1 beta was blocked by a human recombinant interleukin-1 receptor antagonist. The inhibitory effect of interleukin-1 beta was also abolished by the cyclooxygenase inhibitor, diclofenac (1 mumol/l) suggesting that the action of interleukin-1 beta might be mediated through the formation of prostaglandins. The effect of interleukin-1 beta appears to be time-dependent, since a stronger inhibition of radio-activity release was observed when the incubation time was increased from 20 to 65 minutes before the second stimulation. Interleukin-2 and interleukin-6 were ineffective in modulating release under these experimental conditions. The ability of interleukin-1 beta and tumor necrosis factor-alpha to inhibit noradrenaline release suggests that mediators of the immune system produced locally may modulate the activity of the sympathetic nervous system.

Effect of in vivo heart irradiation on the development of antioxidant defenses and cardiac functions in the rat

During radiotherapy of thoracic tumors, the heart is often included in the primary treatment volume, and chronic impairment of myocardial function occurs. The cellular biomolecules are altered directly by radiation or damaged indirectly by free radical production. The purpose of this investigation was to evaluate the biochemical and functional responses of the rat heart to a single high dose of radiation. The effect of 20 Gy local X irradiation was determined in the heart of Wistar rats under general anesthesia. Mechanical performances were measured in vitro using an isolated perfused working heart model, and cardiac antioxidant defenses were also evaluated. Hearts were studied at 1 and 4 months after irradiation. This single dose of radiation induced a marked drop in the mechanical activity of the rat heart: aortic output was significantly reduced (18% less than control values) at 1 month postirradiation and remained depressed for the rest of the experimental period (21% less than control 4 months after treatment). This suggests the development of myocardial failure after irradiation. The decline of functional parameters was associated with changes in antioxidant defenses. The decrease in cardiac levels of vitamin E (-30%) was associated with an increase in the levels of Mn-SOD and glutathione peroxidase (+45.5% and +32%, respectively, at 4 months postirradiation). However, cardiac vitamin C and catalase levels remained constant. Since these antioxidant defenses were activated relatively long after irradiation, it is suggested that this was probably due to the production of free radical species associated with the development of inflammation.