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J Cañón

Publications and source records attributed to J Cañón.

18 recordsLinked to original sources
PubMed2006

Geographical partitioning of goat diversity in Europe and the Middle East.

Thirty microsatellite markers were analysed in 1426 goats from 45 traditional or rare breeds in 15 European and Middle Eastern countries. In all populations inbreeding was indicated by heterozygosity deficiency (mean FIS = 0.10). Genetic differentiation between breeds was moderate with a mean FST value of 0.07, but for most (c. 71%) northern and central European breeds, individuals could be assigned to their breeds with a success rate of more than 80%. Bayesian-based clustering analysis of allele frequencies and multivariate analysis revealed at least four discrete clusters: eastern Mediterranean (Middle East), central Mediterranean, western Mediterranean and central/northern Europe. About 41% of the genetic variability among the breeds could be explained by their geographical origin. A decrease in genetic diversity from the south-east to the north-west was accompanied by an increase in the level of differentiation at the breed level. These observations support the hypothesis that domestic livestock migrated from the Middle East towards western and northern Europe and indicate that breed formation was more systematic in north-central Europe than in the Middle East. We propose that breed differentiation and molecular diversity are independent criteria for conservation.

Animals↗
PubMed2006

Analysis of genetic diversity and the determination of relationships among western Mediterranean horse breeds using microsatellite markers.

The distribution of genetic diversity and the genetic relationships among western Mediterranean horse breeds were investigated using microsatellite markers. The examined sample included seven Spanish and three Italian local horse breeds and populations, plus a Spanish Thoroughbred outgroup. The total number of animals examined was 682 (on average 62 animals per breed; range 20-122). The microsatellite marker set analysed provided 128 alleles (10.7 alleles per locus). Within-breed genetic diversity was always high (>0.70), with breeds contributing about 8% of the total genetic variability. The mean molecular coancestry of the entire population examined was 0.205, Losino being the breed that contributed most. In addition to Nei's standard and Reynolds' genetic distances, pair-wise kinship distance and molecular coancestry were estimated. Remarkably similar breed rankings were obtained with all methods. Clustering analysis provided an accurate representation of the current genetic relationships among the breeds. Determining coancestry is useful for analysing genetic diversity distribution between and within breeds and provides a good framework for jointly analysing molecular markers and pedigree information. An integrated analysis was undertaken to obtain information on the population dynamics in western Mediterranean native horse populations, and to better determine conservation priorities.

Alleles↗
PubMed2005

Combining inter- and intrapopulation information with the Weitzman approach to diversity conservation.

This article introduces a new perspective on Weitzman's methodology for assessing the distribution of resources in genetic diversity conservation programs. Intrapopulation information is added to the procedure by diffusion process formulas to calculate genetic extinction probabilities, and therefore the marginal diversities and elasticities of diversity. The method was tested with a set of European cattle breeds from Spain and France and provided satisfactory results.

Algorithms↗
PubMed2005

Urgent lung transplantation in Spain.

BACKGROUND: Lung donors are scarce and lung transplantation resources are limited. Because urgent lung transplantation (ULT) is assumed to yield poor results, its use is controversial. We assessed the outcome of patients who received ULT seeking to determine effectiveness and risk factors. PATIENTS AND METHOD: We collected data from every ULT performed in Spain during 5 years (1998-2002). The survival of patients was studied using Kaplan-Meier, Cox regression, and chi-square statistical analyses. We compared outcomes and perioperative mortality (over 30 days) for ULT procedures, analyzing the influence of certain variables (age, type of transplant, diagnosis, indication, and time on waiting list). RESULTS: Among 109 patients proposed for the procedure, 73 ULT were performed during the period. The most frequent indications were pulmonary fibrosis (19 cases) and cystic fibrosis (19 cases), showing the worst and the better survival rates, respectively. The bad prognosis, determined mainly by per operative mortality rate (35.62%), was significantly affected by age (worse for patients older than 40 years) and type of LT (single worse than double; P < .05). A longer time waiting for ULT also showed a worse prognosis (P < .005). CONCLUSIONS: Long-term survival after ULT shows that the procedure is effective and efficient for a select group of patients, despite the high per operative risk. ULT should be reserved for younger patients. It also requires performance in a short period (just a few days), initially rejecting a single lung transplant, provided that the patient is adequately monitored.

Humans↗
PubMed2003

Disparities in access to liver transplantation in Spain.

BACKGROUND: The maintenance of an equitable system for access to transplantation is a matter of concern to all professionals involved in this field. Any national system must ensure equity. METHODS: The rates of indication for liver transplantation have been reviewed for all Spanish regions. The time to transplantation was evaluated with respect to different recipient characteristics and donor rates. The indication rates for liver transplantation are similar in the different countries with liver transplant programs but are far from similar among different regions in Spain. This suggests that there is not equity in the access to liver transplantation. RESULTS: A review of the factors affecting the waiting times to transplantation after being registered for the waiting list shows that some groups of patients are currently waiting less time than others. Shorter waiting times occur in patients of the AB group, children, patients with hepatocarcinoma, and patients living in the zone of Valencia, despite similar organ donation rates in all transplant zones. CONCLUSION: Neither the rate nor the probability of liver transplantation is affected exclusively by the organ donation rate in Spain but also depends on the number of patients admitted to the waiting list. Despite the existence of an organ allocation system that is center-oriented, liver patients are receiving grafts mainly based on the severity of the illness, because clearance rates from the waiting list of both dead patients and grafted patients are the same.

Geography↗
PubMed2003

Kidney donor profile in Spain: risks factors and characteristics of the organs rejected for transplantation.

During recent years organ donation in Spain has increased by 100%, with important changes seen in the donor profile. Mean age has increased by more than 10 years, being nowadays more than 33% of our donors over 60 years. Ten years ago road traffic trauma was the main cause of death, while now most of our donors die due to stroke and only 21% die in a traffic accident. This changes lead to an increase in the number of kidneys discarded for transplantation every year. Among the 2517 kidneys retrieved during 2001, 567 were discarded, mainly due to different glomerular, interstitial or vascular pathologic damage. The older is the donor the higher is the percentage of kidneys discarded. It has to be underlined that an increased number of livers from donors, whose kidneys could not be used, are being grafted (141 in 2001 over 281 donors from whom no kidney could be grafted and over a total number of 1335 donors). Only 5% of kidneys were discarded due to technical problems. An important number of kidneys were discarded due to malignancy suspicion or diagnosis (12.3%). Organ donation has improved but kidney transplantation did not in parallel, due to the increasing number of kidneys discarded for transplantation in close relation with the evolution of donor's characteristics. Organ donation rate is around 33 donors per million population while efficient organ donation rate is around 30 donors per million. Only from 67% of donors both kidneys can be grafted and from 20% of donors no kidney can be used. These data will not change our policy, at least by the moment, we will continue to evaluate every potential brain death donor with the aim of studying if organs can be used. It is true that in 50% of cases over 70 years no organ can be used after retrieval and microscopic exam, but in the other 50% we can proceed.

Age Factors↗
PubMed2002

Prediction of X and Y chromosome content in bovine sperm by using DNA pools through capillary electrophoresis.

Livestock resource management through gender offspring preselection is an efficient tool in terms of genetic improvement and farm management and additionally provides the opportunity to adjust offspring to market demands. In this study bull ejaculates were tested using PCR amplification of a segment of the X-Y homologous amelogenin gene in order to estimate the X and Y chromosome frequencies by capillary electrophoresis. Results were quantified against a regression function constructed with pools prepared with DNA from bulls and cows with known X and Y ratios. An average of 50.02 +/- 2.79% X chromosome content was found with normal distribution ranging from 38.7 to 58.2%. Bull effect was significant in the analysis of variance representing 8.5% of the total variance. This simple analysis provides a low-cost and quick method of evaluating an X-Y ratio in a high number of ejaculates, particularly when external factors can be manipulated to alter it.

Amelogenin↗
PubMed2002

Sib-parentage testing using molecular markers when parents are unknown.

The formulae for computing the so-called Sib Index using codominant alleles for (1) full-sib and (2) half-sib parentage are given. Hypothesis testing is based on the distribution of conditional likelihood ratio or Bayes' factor. Thresholds for rejecting the null hypothesis and P-values were obtained in function of the number of alleles and their frequency distributions. Simulations showed that a relatively low number of marker systems (e.g. 20) are enough to accept the hypothesis of sib parentage with a reasonable power for usual significance levels, but that a higher number would be necessary if full-sib against half-sib parentage is the contrast to be carried out. The effect of sampling variation on the allele frequencies on power calculations is also analysed.

Alleles↗
PubMed1999

Technical note: use of PCR-single-strand conformation polymorphism analysis for detection of bovine beta-casein variants A1, A2, A3, and B.

We have optimized the polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) technique to screen the most frequent variants (A1, A2, A3, and B) of the bovine beta-casein gene. Five partly overlapping PCR products (233, 234, 265, 466, and 498 bp) of Exon VII of the beta-casein gene that encompass the target point mutations were heat-denatured, separated on nondenaturing polyacrylamide gels, and silver-stained. Simultaneous detection of all variants in reference samples of known genotypes (A1A2, A2A2, A1A3, A1B, and A2B) was best achieved on 17% polyacrylamide (100:1 acrylamide:bis-acrylamide ratio) gels with the PCR product of 234 bp. These results were confirmed by sequencing the allele-specific SSCP bands directly excised from polyacrylamide gels. A population of 65 anonymous samples belonging to various breeds was then analyzed twice, without discrepancies in a blind trial. Routine beta-casein genotyping using PCR-SSCP is proposed as a cost-effective, fast, and sensitive technique.

Animals↗
PubMed1998

Technical note: Detection of bovine kappa-casein variants A, B, C, and E by means of polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP).

We used polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis to screen the most frequent variants (A, B, C, and E) found in the bovine kappa-casein gene. The PCR products (453 bp) were heat-denatured, loaded onto nondenaturing polyacrylamide gels, and silver-stained. Each variant yielded patterns clearly distinguishable from the others. Optimal conditions for the simultaneous detection of the four variants were 12% polyacrylamide gels (100:1 acrylamide:bis-acrylamide ratio) with 5% glycerol and a constant running temperature of 10 degrees C. Eight reference samples initially used for this purpose and 40 anonymous samples of different cattle breeds diagnosed by PCR-RFLP and PCR-SSCP showed no discrepancies between the two methods and confirmed previous results. Because it is cost-effective, sensitive, and fast, PCR-SSCP is strongly recommended to routinely screen kappa-casein variants for industrial purposes or in cattle selection schemes.

Alleles↗
PubMed1997

Nosocomial transmission of Mycobacterium bovis resistant to 11 drugs in people with advanced HIV-1 infection.

BACKGROUND: Since 1990, several nosocomial outbreaks of multidrug-resistant (MDR) tuberculosis have occurred, none of which have involved Mycobacterium bovis. We describe an epidemic of nosocomial and primary MDR M bovis tuberculosis from December, 1993, to February, 1995, among HIV-1-infected patients in a district of Madrid. METHODS: We undertook genetic characterisation of the M bovis strain and investigated its presence in a tuberculosis epidemic in a Madrid hospital in a case-controlled study. We assessed 19 cases diagnosed with MDR tuberculosis due to M bovis during the study period. For the control group, we randomly selected 33 patients with HIV-1 infection and isolation of a strain of M tuberculosis susceptible to isoniazid, rifampicin, or both, who were treated in Ramón y Cajal Hospital. Infection-control policies and practices were implemented. FINDINGS: We detected 19 cases in HIV-1-infected patients of primary MDR tuberculosis produced by M bovis resistant to 11 antituberculosis drugs. We found phenotypic and genotypic similarities in the strains of M bovis. In the case group, the index case and two other cases had had previous contact with another hospital that had had an MDR tuberculosis outbreak. All patients died after a mean of 44 days (range 2-116), despite multidrug treatment with first-line and second-line antituberculosis drugs. The cases with M bovis MDR tuberculosis were significantly more likely than controls to have been admitted to a hospital ward at the same time as patients already infected with MDR tuberculosis during the 10 months before their diagnosis (adjusted odds ratio 94.6 [95% CI 9.4-956.3], p < 0.0001). Advanced HIV-1 immunosuppression was associated with the development of MDR tuberculosis. Implementation of control measures stopped the epidemic. INTERPRETATION: An M bovis primary MDR tuberculosis epidemic that cannot be treated effectively and with high mortality has emerged in Europe and has been transmitted between hospitals.

AIDS-Related Opportunistic Infections↗
PubMed1997

Pulmonary and extrapulmonary tuberculosis at AIDS diagnosis in Spain: epidemiological differences and implications for control.

OBJECTIVE: To ascertain the differential factors associated with pulmonary versus extrapulmonary tuberculosis (TB) at AIDS diagnosis in Spain. DESIGN: Analysis of AIDS surveillance data. METHODS: Data about AIDS patients, aged 12 years and over, diagnosed in 1995 were taken from the Spanish AIDS Register. The respective proportions of cases presenting with pulmonary and extrapulmonary TB at AIDS diagnosis were analysed by gender, age, HIV transmission category, prison record, province, country of origin and CD4+ lymphocyte count. A multivariate analysis was carried out using logistic regression analysis. RESULTS: Of 6161 AIDS cases analysed, 20.1% presented with pulmonary TB and 20.4% with extrapulmonary TB. Overall, TB showed association with men, age under 30 years, injecting drug users (IDU), cases of heterosexual HIV transmission, and concurrent or past stay in prison. Frequency of TB proved no different among foreign-born patients. Pulmonary and extrapulmonary TB showed a similar distribution for most of the variables. Current prison inmates registered a high risk of pulmonary TB [adjusted odds ratio (OR), 4.2; 99% confidence interval (CI), 3.1-5.8] compared with patients without prison record, and ex-prison inmates registered an intermediate risk (OR, 2.3; 99% CI, 1.8-3.0). Among patients with TB at AIDS diagnosis, pulmonary TB was associated with subjects currently in prison (OR, 2.1; 99% CI, 1.5-3.0) and injecting drug use (OR, 1.5; 99% CI, 1.0-2.4). Pulmonary TB presented with higher CD4+ lymphocyte counts than extrapulmonary TB (P < 0.001). CONCLUSIONS: The results suggest the importance that recent transmission of TB may be having among young adults, IDU and prison inmates in particular, and calls for a review of control strategies.

AIDS-Related Opportunistic Infections↗
PubMedDate not supplied

Power analysis of QTL detection in half-sib families using selective DNA pooling.

Individual loci of economic importance (QTL) can be detected by comparing the inheritance of a trait and the inheritance of loci with alleles readily identifiable by laboratory methods (genetic markers). Data on allele segregation at the individual level are costly and alternatives have been proposed that make use of allele frequencies among progeny, rather than individual genotypes. Among the factors that may affect the power of the set up, the most important are those intrinsic to the QTL: the additive effect of the QTL, and its dominance, and distance between markers and QTL. Other factors are relative to the choice of animals and markers, such as the frequency of the QTL and marker alleles among dams and sires. Data collection may affect the detection power through the size of half-sib families, selection rate within families, and the technical error incurred when estimating genetic frequencies. We present results for a sensitivity analysis for QTL detection using pools of DNA from selected half-sibs. Simulations showed that conclusive detection may be achieved with families of at least 500 half-sibs if sires are chosen on the criteria that most of their marker alleles are either both missing, or one is fixed, among dams.

Alleles↗
PubMedDate not supplied

Genetic diversity measures of local European beef cattle breeds for conservation purposes.

This study was undertaken to determine the genetic structure, evolutionary relationships, and the genetic diversity among 18 local cattle breeds from Spain, Portugal, and France using 16 microsatellites. Heterozygosities, estimates of Fst, genetic distances, multivariate and diversity analyses, and assignment tests were performed. Heterozygosities ranged from 0.54 in the Pirenaica breed to 0.72 in the Barrosã breed. Seven percent of the total genetic variability can be attributed to differences among breeds (mean F(st) = 0.07; P<0.01). Five different genetic distances were computed and compared with no correlation found to be significantly different from 0 between distances based on the effective size of the population and those which use the size of the alleles. The Weitzman recursive approach and a multivariate analysis were used to measure the contribution of the breeds diversity. The Weitzman approach suggests that the most important breeds to be preserved are those grouped into two clusters: the cluster formed by the Mirandesa and Alistana breeds and that of the Sayaguesa and Tudanca breeds. The hypothetical extinction of one of those clusters represents a 17% loss of diversity. A correspondence analysis not only distinguished four breed groups but also confirmed results of previous studies classifying the important breeds contributing to diversity. In addition, the variation between breeds was sufficiently high so as to allow individuals to be assigned to their breed of origin with a probability of 99% for simulated samples.

Algorithms↗