The Influence of number and timing of pregnancies on breast cancer risk for women with BRCA1 or BRCA2 mutations

Background: Full-term pregnancy (FTP) is associated with a reduced breast cancer (BC) risk over time, but women are at increased BC risk in the immediate years following an FTP. No large prospective studies, however, have examined whether the number and timing of pregnancies are associated with BC risk for BRCA1 and BRCA2 mutation carriers.Methods: Using weighted and time-varying Cox proportional hazards models, we investigated whether reproductive events are associated with BC risk for mutation carriers using a retrospective cohort (5707 BRCA1 and 3525 BRCA2 mutation carriers) and a prospective cohort (2276 BRCA1 and 1610 BRCA2 mutation carriers), separately for each cohort and the combined prospective and retrospective cohort.Results: For BRCA1 mutation carriers, there was no overall association with parity compared with nulliparity (combined hazard ratio [HRc] = 0.99, 95% confidence interval [CI] = 0.83 to 1.18). Relative to being uniparous, an increased number of FTPs was associated with decreased BC risk (HRc = 0.79, 95% CI = 0.69 to 0.91; HRc =0.70, 95% CI = 0.59 to 0.82; HRc = 0.50, 95% CI = 0.40 to 0.63, for 2, 3, and >= 4 FTPs, respectively, P-trend < .0001) and increasing duration of breastfeeding was associated with decreased BC risk (combined cohort P-trend = .0003). Relative to being nulliparous, uniparous BRCA1 mutation carriers were at increased BC risk in the prospective analysis (prospective hazard ration [HRp] =1.69, 95% CI =1.09 to 2.62). For BRCA2 mutation carriers, being parous was associated with a 30% increase in BC risk (HRc =1.33, 95% CI =1.05 to 1.69), and there was no apparent decrease in risk associated with multiparity except for having at least 4 FTPs vs. 1 FTP (HRc =0.72, 95% CI = 0.54 to 0.98).Conclusions: These findings suggest differential associations with parity between BRCA1 and BRCA2 mutation carriers with higher risk for uniparous BRCA1 carriers and parous BRCA2 carriers

The Influence of Number and Timing of Pregnancies on Breast Cancer Risk for Women With BRCA1 or BRCA2 Mutations

Background: Full-term pregnancy (FTP) is associated with a reduced breast cancer (BC) risk over time, but women are at increased BC risk in the immediate years following an FTP. No large prospective studies, however, have examined whether the number and timing of pregnancies are associated with BC risk for BRCA1 and BRCA2 mutation carriers. Methods: Using weighted and time-varying Cox proportional hazards models, we investigated whether reproductive events are associated with BC risk for mutation carriers using a retrospective cohort (5707 BRCA1 and 3525 BRCA2 mutation carriers) and a prospective cohort (2276 BRCA1 and 1610 BRCA2 mutation carriers), separately for each cohort and the combined prospective and retrospective cohort. Results: For BRCA1 mutation carriers, there was no overall association with parity compared with nulliparity (combined hazard ratio [HRc] ¼ 0.99, 95% confidence interval [CI] ¼ 0.83 to 1.18). Relative to being uniparous, an increased number of FTPs was associated with decreased BC risk (HRc¼ 0.79, 95% CI ¼ 0.69 to 0.91; HRc¼ 0.70, 95% CI ¼ 0.59 to 0.82; HRc¼ 0.50, 95% CI ¼ 0.40 to 0.63, for 2, 3, and 4 FTPs, respectively, Ptrend < .0001) and increasing duration of breastfeeding was associated with decreased BC risk (combined cohort Ptrend ¼ .0003). Relative to being nulliparous, uniparous BRCA1 mutation carriers were at increased BC risk in the prospective analysis (prospective hazard ration [HRp] ¼ 1.69, 95% CI ¼ 1.09 to 2.62). For BRCA2 mutation carriers, being parous was associated with a 30% increase in BC risk (HRc ¼ 1.33, 95% CI ¼ 1.05 to 1.69), and there was no apparent decrease in risk associated with multiparity except for having at least 4 FTPs vs. 1 FTP (HRc¼ 0.72, 95% CI ¼ 0.54 to 0.98). Conclusions: These findings suggest differential associations with parity between BRCA1 and BRCA2 mutation carriers with higher risk for uniparous BRCA1 carriers and parous BRCA2 carriers

Genomics, proteomics and metabolomics: Their emerging roles in the discovery and validation of rheumatoid arthritis biomarkers

Rheumatoid arthritis (RA) is an autoimmune inflammatory rheumatic disease which affects several organs and tissues, predominantly the synovial joints. Despite major advances, the aetiology of this disease is not completely understood. Although several biomarkers are routinely used in RA management and some of them can be detected even prior to the onset of the clinical disease, there is a high demand for novel biomarkers to further improve the early diagnosis of RA. The '-omics' techniques that have emerged and have been developed in recent years have allowed researchers to improve their knowledge of the aetiopathology of RA. At the same time, advances in screening technologies offer an excellent opportunity to find new biomarkers potentially useful for early diagnosis, stratification of patients, and even prediction of a better response to a specific therapy. This review describes what is known about the methodologies used in the discovery of novel biomarkers in RA, along with the findings of these methodologies, with specific attention to recent advances in the fields of genomics, proteomics and metabolomics. © Clinical and Experimental Rheumatology 2015.Universidad Autónoma de Chil

Desarrollo de un antígeno para diagnóstico del parvovirus de las ratas (virus Kilham) por la técnica de inhibición de la hemaglutinación Development of an antigen for the diagnosis of Kilham rat parvovirus by hemagglutination inhibition test

Se desarrolló un antígeno (Ag) para el diagnóstico de la infección por parvovirus Kilham de las ratas (KRV) por la técnica de inhibición de la hemaglutinación (IHA). Para su elaboración se utilizaron cultivos primarios de fetos de ratas, infectados con KRV, los que fueron cosechados a diferentes tiempos posinfección, centrifugados y cada sedimento celular resuspendido en un volumen 100 veces menor al original. Cada muestra fue posteriomente sonicada, centrifugada y el sobrenadante (Ag) fue titulado por hemaglutinación (HA). El Ag elaborado a partir de células al 5to día posinfección ofreció el mejor título hemaglutinante. La especificidad del mismo fue confirmada por IHA con sueros específicos de referencia positivo y negativo a KRV y positivos a otros agentes infecciosos virales y bacterianos. Se analizaron 98 sueros por IHA y los resultados coincidieron con los obtenidos por un laboratorio de referencia. El Ag producido resultó específico, sensible, de fácil elaboración y de gran utilidad para el control de las colonias de ratas de producción y experimentación del país.An antigen of rat parvovirus (Kilham virus) was developed for the diagnosis of viral infection in rat colonies by using hemagglutination inhibition (HAI) test. Primary cell cultures from rat embryos were infected with Kilham rat virus. Infected cells obtained at different time post infection were scraped, centrifuged, concentrated one hundred times, sonicated and centrifuged again. The supernatants obtained were titrated by hemagglutination. The specificity was confirmed with positive and negative reference sera. Ninety eight serum samples were studied by using HAI test. The results coincided with those obtained in a reference laboratory. Kilham rat parvovirus antigen obtained from 5 days-infected-cells was specific, sensitive, easy to prepare, with a high yield and it is useful to detect this virus in experimental and production rat colonies

Site-specific PEGylation of protein bisulfide bonds using a three-carbon bridge

The covalent conjugation of a functionalized poly(ethylene glycol) (PEG) to multiple nucleophilic amine residues results in a heterogeneous mixture of PEG positional isomers. Their physicochemical, biological, and pharmaceutical properties vary with the site of conjugation of PEG. Yields are low because of inefficient conjugation chemistry and production costs high because of complex purification procedures. Our solution to these fundamental problems in PEGylating proteins has been to exploit the latent conjugation selectivity of the two sulfur atoms that are derived from the ubiquitous disulfide bonds of proteins. This approach to PEGylation involves two steps: (1) reduction to release the two cysteine thiols and (2) re-forming the disulfide by bis-alkylation via a three-disulfide carbon bridge to which PEG was covalently attached. During this process, irreversible denaturation of the protein did not occur. Mechanistically, the conjugation is conducted by a sequential, interactive bis-alkylation using α,β-unsaturated β′- monosulfone functionalized PEG reagents. The combination of (a) maintaining the protein's tertiary structure after disulfide reduction, (b) the mechanism for bis-thiol selectivity of the PEG reagent, and (c) the steric shielding of PEG ensure that only one PEG molecule is conjugated at each disulfide bond. PEG was site-specifically conjugated via a three-carbon bridge to 2 equiv of the tripeptide glutathione, the cyclic peptide hormone somatostatin, the tetrameric protein L-asparaginase, and to the disulfides in interferon α-2b (IFN). SDS-PAGE, mass spectral, and NMR analyses were used to confirm conjugation, thiol selectivity, and connectivity. The biological activity of the L-asparaginase did not change after the attachment of four PEG molecules. In the case of IFN, a small reduction in biological activity was seen with the single-bridged IFN (without PEG attached). A significantly larger reduction in biological activity was seen with the three-carbon disulfide single-bridged PEG-IFNs and with the double-bridged IFN (without PEG attached). The reduction of the PEG-IFN's in vitro biological activity was a consequence of the steric shielding caused by PEG, and it was comparable to that seen with all other forms of PEG-IFNs reported. However, when a three-carbon bridge was used to attach PEG, our PEG-IFN's biological activity was found to be independent of the length of the PEG. This property has not previously been described for PEG-IFNs. Our studies therefore suggest that peptides, proteins, enzymes, and antibody fragments can be site-specifically PEGylated across a native disulfide bond using three-carbon bridges without destroying their tertiary structure or abolishing their biological activity. The stoichiometric efficiency of this approach also enables recycling of any unreacted protein. It therefore offers the potential to make PEGylated biopharmaceuticals as cost-effective medicines for global use

Convergent and construct validity and test–retest reliability of the Caen Chronotype Questionnaire in six languages

Chronotype questionnaires provide a simple and time-effective approach to assessing individual differences in circadian variations. Chronotype questionnaires traditionally focused on one dimension of chronotype, namely its orientation along a continuum of morningness and eveningness. The Caen Chronotype Questionnaire (CCQ) was developed to assess an additional dimension of chronotype that captures the extent to which individual functioning varies during the day (amplitude). The aim of this study was to provide a multilanguage validation of the CCQ in six world regions (Arabic, Dutch, German, Italian, Portuguese and Spanish). At Time 1, a total of 2788 participants agreed to take part in the study (Arabic, n = 731; Dutch, n = 538; German, n = 329; Italian, n = 473; Portuguese, n = 361; Spanish, n = 356). Participants completed an assessment of the CCQ together with the Morningness-Eveningness Questionnaire (MEQ; Horne & Ostberg 1976) as well as questions related to factors theoretically related to chronotype (age, shift work, physical activity, sleep parameters and coffee consumption). One month later, participants again completed the CCQ. Results showed that the two-factor structure (morningness-eveningness and amplitude) of the CCQ could be replicated in all six languages. However, measurement invariance could not be assumed regarding the factor loadings across languages, meaning that items loaded more on their factors in some translations than in others. Test–retest reliability of the CCQ ranged from unacceptable (German version) to excellent (Dutch, Portuguese). Convergent validity was established through small–medium effect size correlations between the morningness-eveningness dimension of the CCQ and the MEQ. Taken together, our findings generally support the use of the translated versions of the CCQ. Further validation work on the CCQ is required including convergent validation against physiological markers of sleep, health and well-being