Genetic parameters of resistance to pasteurellosis using novel response traits in rabbits.

BACKGROUND: Pasteurellosis (Pasteurella infection) is one of the most common bacterial infections in rabbits on commercial farms and in laboratory facilities. Curative treatments using antibiotics are only partly efficient, with frequent relapses. Breeding rabbits for improved genetic resistance to pasteurellosis is a sustainable alternative approach. In this study, we infected 964 crossbred rabbits from six sire lines experimentally with Pasteurella multocida. After post-mortem examination and bacteriological analyses, abscess, bacteria, and resistance scores were derived for each rabbit based on the extent of lesions and bacterial dissemination in the body. This is the first study to use such an experimental design and response traits to measure resistance to pasteurellosis in a rabbit population. We investigated the genetic variation of these traits in order to identify potential selection criteria. We also estimated genetic correlations of resistance to pasteurellosis in the experimental population with traits that are under selection in the breeding populations (number of kits born alive and weaning weight). RESULTS: Heritability estimates for the novel response traits, abscess, bacteria, and resistance scores, ranged from 0.08 (± 0.05) to 0.16 (± 0.06). The resistance score showed very strong negative genetic correlation estimates with abscess (- 0.99 ± 0.05) and bacteria scores (- 0.98 ± 0.07). A very high positive genetic correlation of 0.99 ± 0.16 was estimated between abscess and bacteria scores. Estimates of genetic correlations of the resistance score with average daily gain traits for the first and second week after inoculation were 0.98 (± 0.06) and 0.70 (± 0.14), respectively. Estimates of genetic correlations of the disease-related traits with average daily gain pre-inoculation were favorable but with high standard errors. Estimates of genetic and phenotypic correlations of the disease-related traits with commercial selection traits were not significantly different from zero. CONCLUSIONS: Disease response traits are heritable and are highly correlated with each other, but do not show any significant genetic correlations with commercial selection traits. Thus, the prevalence of pasteurellosis could be decreased by selecting more resistant rabbits on any one of the disease response traits with a limited impact on the selection traits, which would allow implementation of a breeding program to improve resistance to pasteurellosis in rabbits.

Incidence, Predictive Factors, and Prognostic Impact of Silent Atrial Fibrillation After Transcatheter Aortic Valve Implantation.

New onset atrial fibrillation post-transcatheter aortic valve implantation (TAVI) is common and is associated with adverse outcomes. However, silent atrial fibrillation (AF) is poorly documented in the context. This study sought to evaluate the incidence, predictive factors, and prognostic value of Silent AF post-TAVI. All the consecutive patients with TAVI were prospectively analyzed by continuous electrocardiogram monitoring≥48 hours after implantation. Silent AF was defined as asymptomatic episodes lasting at least 30 seconds. The population was divided into 3 groups: history of AF, no-AF, and silent AF. Among the 206 patients implanted with TAVI, 19 (16.1%) developed silent AF. Compared with the no-AF group, patients with silent AF shared the same clinical characteristics and cardiovascular risk factors. Procedural success and echography parameters after the device implantation were similar between groups. Left atrial volume was significantly increased (p <0.001) in the silent AF group, together with preimplantation C-reactive protein (CRP) >3 mg/L and glucose (p = 0.048 and p = 0.002). By multivariate analysis, CRP >3 mg/dl and logistic European System for Cardiac Operative Risk Evaluation were identified as independent predictors of silent AF. In-hospital and 1-year mortalities were higher in pre-existing AF patients, whereas no-AF and the silent AF patients share the same prognosis. Our prospective study showed for the first time that silent AF is frequent after TAVI procedures. In conclusion, our work suggests that CRP could help to predict the risk of developing silent AF. However, the onset of silent AF is not associated with worse prognosis in the year following the procedure in our study.

Blood Transfusion in Elderly Patients with Acute Myocardial Infarction: Data from the RICO Survey.

BACKGROUND: Red blood cell transfusion benefit during acute myocardial infarction remains unclear in the elderly. We aimed to assess the transfusion impact on 1-year mortality in acute myocardial infarction patients aged ≥65 years, according to their age and hemoglobin nadir. METHODS: We included 3316 consecutive patients with acute myocardial infarction aged ≥65 years from the "obseRvatoire des Infarctus de Côte d'Or" (RICO) survey. They were categorized according to their hemoglobin nadir (≤8, >8 to ≤10, and >10 g/dL) and age (<80 or ≥80 years). RESULTS: A total of 1906 patients (57%) were 65-79 years old, and 1410 (43%) were aged ≥80 years, of whom 103 (5%) and 145 (10%) patients received red blood cell transfusion, respectively (P < .001). In Cox regression analysis, transfusion was associated with increased 1-year mortality for hemoglobin nadir >10 g/dL but no significant effect for hemoglobin nadir between 8 and 10 g/dL. When hemoglobin nadir was ≤8 g/dL, transfusion did not influence 1-year mortality for younger patients (65-79 years). However, for older patients (≥80 years), transfusion was associated with lower mortality (hazard ratio 0.43 [95% confidence interval, 0.22-0.86], P = .016). CONCLUSION: Among older patients with acute myocardial infarction, the effect of transfusion was largely dependent on hemoglobin threshold and age. Transfusion was associated with increased 1-year mortality when hemoglobin nadir was >10 g/dL. However, in patients aged ≥80 years with hemoglobin nadir <8 g/dL, transfusion was associated with a 50% reduction in 1-year mortality.

Alkaptonuria in France: past experience and lessons for the future.

Alkaptonuria (AKU) is an autosomal recessive disorder due to homogentisate 1,2-dioxygenase (HGD) deficiency in the liver and characterized by a triad of signs, according to chronology of appearance: homogentisic aciduria (HGA) or alkaptonuria, ochronosis then ochronotic arthropathy. This inborn error of metabolism is caused by mutations in the HGD gene. In this work we report observations of 96 AKU French patients from 81 families collected in the literature since 1882 and from our personal contribution since 1986, giving an incidence of the disease of around 1:680,000 (96/64.10(6)). As expected for an autosomal recessive disorder the main findings of this study were: a slight predominance of males (51/93, 54,8%) over females (42/93, 45,2%), a strong predominance of sibships with one affected individual (68/81, 84,0%) over sibships with two (11/81, 13.6%) and three(2/81, 2.4%) affected individuals. AKU families are scaterred among the French territory suggesting that most cases occured in non-consanguineous unions. Consanguinity was only found in five families. Other peculiarities of this study were (a) ten of these families have both parents from a foreign geographical origin: Poland(3), Italy(3), Portugal(2), Ukraine(1) and India(1) and four families with only one foreign parent (Algeria, Armenia, Serbia, UK), (b) HGD mutations were found in 23 families, (c) four of theses 96 patients were seen by us respectively 28, 29, 39 and 45 years after their report in the literature and (d) seven patients present cardiac and/or renal complications.

Intermediates in wet oxidation of cellulose: identification of hydroxyl radical and characterization of hydrogen peroxide.

Some intermediates were identified during the course of non-catalytic wet air oxidation (WAO) of cellulose. Concentrations of by-products were determined in function of temperature and reaction time. This study also showed that hydroxyl radicals (HO*) and hydrogen peroxide (H2O2) play the role of intermediates in the initial phase of the oxidation reactions. Hydroxyl radicals were detected by the electron spin resonance spectroscopy coupled to the spin trapping technique using the 5,5-dimethyl 1-pyrroline N-oxide (DMPO) as spin trap agent. The spin adduct (DMPO/ HO*), resulting from the trapping of HO* with DMPO, showed a characteristic electron spin resonance signal which was inhibited when catalase was added, indicating that HO* was provided from H2O2. These transient species were only observed at the beginning of the reaction and were not oxygen dependent.