Hepatic safety of antibiotics used in primary care

Antibiotics used by general practitioners frequently appear in adverse-event reports of drug-induced hepatotoxicity. Most cases are idiosyncratic (the adverse reaction cannot be predicted from the drug's pharmacological profile or from pre-clinical toxicology tests) and occur via an immunological reaction or in response to the presence of hepatotoxic metabolites. With the exception of trovafloxacin and telithromycin (now severely restricted), hepatotoxicity crude incidence remains globally low but variable. Thus, amoxicillin/clavulanate and co-trimoxazole, as well as flucloxacillin, cause hepatotoxic reactions at rates that make them visible in general practice (cases are often isolated, may have a delayed onset, sometimes appear only after cessation of therapy and can produce an array of hepatic lesions that mirror hepatobiliary disease, making causality often difficult to establish). Conversely, hepatotoxic reactions related to macrolides, tetracyclines and fluoroquinolones (in that order, from high to low) are much rarer, and are identifiable only through large-scale studies or worldwide pharmacovigilance reporting. For antibiotics specifically used for tuberculosis, adverse effects range from asymptomatic increases in liver enzymes to acute hepatitis and fulminant hepatic failure. Yet, it is difficult to single out individual drugs, as treatment always entails associations. Patients at risk are mainly those with previous experience of hepatotoxic reaction to antibiotics, the aged or those with impaired hepatic function in the absence of close monitoring, making it important to carefully balance potential risks with expected benefits in primary care. Pharmacogenetic testing using the new genome-wide association studies approach holds promise for better understanding the mechanism(s) underlying hepatotoxicity.

Neuropathologie et pathologie moléculaire des gliomes [Neuropathology and molecular pathology of gliomas]

Gliomas are the most frequent primary brain tumours. The WHO classification is essentially based on histological and immunohistochemical criteria. More recently multiple cytogenetic and molecular alterations associated with initiation and progression have been shown and the genetic profiles of tumour entities have been incorporated in the WHO classifiacation. Molecular testing of the MGMT promotor methylation in glioblastoma, predictive for the response to combined radio-/chimiothérapie, and the LOH 1p/19q in oligodendroglial tumours, as prognostic factor supplements the histopathological diagnosis. In the near futur array-based profiling techniques will contribute to a refinement of glioma classification and identify targets for more individualized glioma therapies.

An unexpected role of semaphorin3a-neuropilin-1 signaling in lymphatic vessel maturation and valve formation.

RATIONALE: Lymphatic vasculature plays important roles in tissue fluid homeostasis maintenance and in the pathology of human diseases. Yet, the molecular mechanisms that control lymphatic vessel maturation remain largely unknown. OBJECTIVE: We analyzed the gene expression profiles of ex vivo isolated lymphatic endothelial cells to identify novel lymphatic vessel expressed genes and we investigated the role of semaphorin 3A (Sema3A) and neuropilin-1 (Nrp-1) in lymphatic vessel maturation and function. METHODS AND RESULTS: Lymphatic and blood vascular endothelial cells from mouse intestine were isolated using fluorescence-activated cell sorting, and transcriptional profiling was performed. We found that the axonal guidance molecules Sema3A and Sema3D were highly expressed by lymphatic vessels. Importantly, we found that the semaphorin receptor Nrp-1 is expressed on the perivascular cells of the collecting lymphatic vessels. Treatment of mice in utero (E12.5-E16.5) with an antibody that blocks Sema3A binding to Nrp-1 but not with an antibody that blocks VEGF-A binding to Nrp-1 resulted in a complex phenotype of impaired lymphatic vessel function, enhanced perivascular cell coverage, and abnormal lymphatic vessel and valve morphology. CONCLUSIONS: Together, these results reveal an unanticipated role of Sema3A-Nrp-1 signaling in the maturation of the lymphatic vascular network likely via regulating the perivascular cell coverage of the vessels thus affecting lymphatic vessel function and lymphatic valve development.

MicroRNA-200 family modulation in distinct breast cancer phenotypes.

The epithelial to mesenchymal transition (EMT) contributes to tumor invasion and metastasis in a variety of cancer types. In human breast cancer, gene expression studies have determined that basal-B/claudin-low and metaplastic cancers exhibit EMT-related characteristics, but the molecular mechanisms underlying this observation are unknown. As the family of miR-200 microRNAs has been shown to regulate EMT in normal tissues and cancer, here we evaluated whether the expression of the miR-200 family (miR-200f) and their epigenetic state correlate with EMT features in human breast carcinomas. We analyzed by qRT-PCR the expression of miR-200f members and various EMT-transcriptional inducers in a series of 70 breast cancers comprising an array of phenotypic subtypes: estrogen receptor positive (ER+), HER2 positive (HER2+), and triple negative (TN), including a subset of metaplastic breast carcinomas (MBCs) with sarcomatous (homologous or heterologous) differentiation. No MBCs with squamous differentiation were included. The DNA methylation status of miR-200f loci in tumor samples were inspected using Sequenom MassArray® MALDI-TOF platform. We also used two non-tumorigenic breast basal cell lines that spontaneously undergo EMT to study the modulation of miR-200f expression during EMT in vitro. We demonstrate that miR-200f is strongly decreased in MBCs compared with other cancer types. TN and HER2+ breast cancers also exhibited lower miR-200f expression than ER+ tumors. Significantly, the decreased miR-200f expression found in MBCs is accompanied by an increase in the expression levels of EMT-transcriptional inducers, and hypermethylation of the miR-200c-141 locus. Similar to tumor samples, we demonstrated that downregulation of miR-200f and hypermethylation of the miR-200c-141 locus, together with upregulation of EMT-transcriptional inducers also occur in an in vitro cellular model of spontaneous EMT. Thus, the expression and methylation status of miR-200f could be used as hypothetical biomarkers to assess the occurrence of EMT in breast cancer.

The involvement of thaumatin-like proteins in plant food cross-reactivity: a multicenter study using a specific protein microarray

Cross-reactivity of plant foods is an important phenomenon in allergy, with geographical variations with respect to the number and prevalence of the allergens involved in this process, whose complexity requires detailed studies. We have addressed the role of thaumatin-like proteins (TLPs) in cross-reactivity between fruit and pollen allergies. A representative panel of 16 purified TLPs was printed onto an allergen microarray. The proteins selected belonged to the sources most frequently associated with peach allergy in representative regions of Spain. Sera from two groups of well characterized patients, one with allergy to Rosaceae fruit (FAG) and another against pollens but tolerant to food-plant allergens (PAG), were obtained from seven geographical areas with different environmental pollen profiles. Cross-reactivity between members of this family was demonstrated by inhibition assays. Only 6 out of 16 purified TLPs showed noticeable allergenic activity in the studied populations. Pru p 2.0201, the peach TLP (41%), chestnut TLP (24%) and plane pollen TLP (22%) proved to be allergens of probable relevance to fruit allergy, being mainly associated with pollen sensitization, and strongly linked to specific geographical areas such as Barcelona, Bilbao, the Canary Islands and Madrid. The patients exhibited >50% positive response to Pru p 2.0201 and to chestnut TLP in these specific areas. Therefore, their recognition patterns were associated with the geographical area, suggesting a role for pollen in the sensitization of these allergens. Finally, the co-sensitizations of patients considering pairs of TLP allergens were analyzed by using the co-sensitization graph associated with an allergen microarray immunoassay. Our data indicate that TLPs are significant allergens in plant food allergy and should be considered when diagnosing and treating pollen-food allergy.

Avaluació de vitamines i antioxidants en aliments vegetals mitjançant tècniques HPLC-DAD i UPLC-MS/MS

El programa experimental s’ha portat a terme dins el marc de les activitats del projecte TRUEFOOD, finançat per la UE per als anys 2007-2010. L’objectiu principal d’aquesta activitat ha estat l’avaluació dels continguts en àcid ascòrbic (vitamina C), polifenols totals, àcids fenòlics i flavonoides en mostres de tomàquet i enciam, produïts sota diferents condicions de camp (producció ecològica i convencional). Per aconseguir els resultats s’han utilitzat mètodes analítics basats en tècniques de cromatografia líquida d’alta eficàcia (HPLC) i d’ultra-alta eficàcia (UHPLC) acoblades a sistemes de detecció de diode array (DAD) i espectrometria de masses (MSn). Per a l’àcid ascòrbic, s’ha desenvolupat un mètode ràpid que ha permès la determinació d’aquest compost en diferents matrius vegetals amb el mínim pretractament de les mostres, utilitzant una fase estacionària HILIC (Fluorinated Stationary Phase). Els mètodes desenvolupats d’anàlisi de compostos fenòlics han permès realitzar les anàlisi de forma ràpida, a fi de processar el màxim nombre de mostres per a obtenir resultats representatius. S’ha realitzat una completa caracterització dels extractes de tomàquet i enciam, ampliant el coneixement descrit en la bibliografia sobre la seva composició fenòlica. En el cas de l’enciam, s’ha identificat quatre compostos fenòlics que mai abans han estat descrits i quantificats en aquesta hortalissa. La definició, amb precisió, dels continguts en vitamina C i compostos fenòlics en les mostres analitzades ha permès comparar els efectes de diferents tècniques de cultiu sobre les característiques nutricionals dels vegetals objecte de l’estudi. Els mètodes d’anàlisi desenvolupats i els resultats derivats del projecte seran publicats properament en revistes científiques de reconegut prestigi.

MsrR contributes to cell surface characteristics and virulence in Staphylococcus aureus.

MsrR, a factor contributing to methicillin resistance in Staphylococcus aureus, belongs to the LytR-CpsA-Psr family of cell envelope-associated proteins. Deletion of msrR increased cell size and aggregation, and altered envelope properties, leading to a temporary reduction in cell surface hydrophobicity, diminished colony-spreading ability, and an increased susceptibility to Congo red. The reduced phosphorus content of purified cell walls of the msrR mutant suggested a reduction in wall teichoic acids, which may explain some of the observed phenotypes. Microarray analysis of the msrR deletion mutant revealed only minor changes in the global transcriptome, suggesting that MsrR has structural rather than regulatory functions. Importantly, virulence of the msrR mutant was decreased in a nematode-killing assay as well as in rat experimental endocarditis. MsrR is therefore likely to play a role in cell envelope maintenance, cell separation, and pathogenicity of S. aureus.

13q deletion syndrome and retinoblastoma in identical dichorionic diamniotic monozygotic twins.

PURPOSE: To report the case of identical dichorionic diamniotic female twins with unilateral retinoblastoma in 13q deletion syndrome. METHODS: Clinical and ophthalmoscopic evaluation, combination of multiple ligation-dependent probe amplification, array-comparative genomic hybridization analyses, and magnetic resonance imaging were performed. RESULTS: Peculiar facial features, marked hypotonia, gastroesophageal reflux, interatrial septal defect with left to right shunt and light dilatation of right chambers, 5th finger hypoplasia, 3rd-5th toes clinodactyly, 2nd toe overlapped to 3rd toe, and cutis marmorata were found. Ophthalmoscopic evaluation revealed unilateral retinoblastoma in both girls. Magnetic resonance imaging detected corpus callosum hypoplasia in both twins. A 34.4-Mb deletion involving bands 13q13.2-q21.33 and including the RB1 gene was identified in both twins. The deletion was not present in the DNA of their parents and older brother. CONCLUSIONS: Dysmorphic features in children must be always suspicious of 13q deletion syndrome and a short ophthalmoscopic follow-up is necessary to detect the presence of a retinoblastoma.

Mitral regurgitation.

Mitral regurgitation (MR) involves systolic retrograde flow from the left ventricle into the left atrium. While trivial MR is frequent in healthy subjects, moderate to severe MR constitutes the second most prevalent valve disease after aortic valve stenosis. Major causes of severe MR in Western countries include degenerative valve disease (myxomatous disease, flail leaflet, annular calcification) and ischaemic heart disease, while rheumatic disease remains a major cause of MR in developing countries. Chronic MR typically progresses insidiously over many years. Once established, however, severe MR portends a poor prognosis. The severity of MR can be assessed by various techniques, Doppler echocardiography being the most widely used. Mitral valve surgery is the only treatment of proven efficacy. It alleviates clinical symptoms and prevents ventricular dilatation and heart failure (or, at least, it attenuates further progression of these abnormalities). Valve repair significantly improves clinical outcomes compared with valve replacement, reducing mortality by approximately 70%. Reverse LV remodelling after valve repair occurs in half of patients with functional MR. Percutaneous, catheter-based to mitral valve repair is a novel approach currently under clinical scrutiny, with encouraging preliminary results. This modality may provide a valuable alternative to mitral valve surgery, especially in critically ill patients.