Comparative Treatment of Mucocutaneous Lesions in Hereditary Haemorrhagic Telangiectasia Patients With Dual Sequential Pulsed Dye Laser and Neodymium: Yttrium-Aluminium-Garnet Versus Neodymium: Yttrium-Aluminium-Garnet Laser Alone: A Double-Blind Randomized Controlled Study With Quality-of-Life Evaluation

BACKGROUND

Hereditary haemorrhagic telangiectasia (HHT) is characterized by the presence of telangiectases and larger arteriovenous malformations in different organs. Mucocutaneous telangiectases can bleed and become an aesthetic concern, impairing quality of life (QoL). However, the best treatment approach has not been defined yet.

OBJECTIVE

To evaluate the efficacy and safety of dual wavelength sequential 595/1064nm laser (DWSL) compared to 1064nm laser (Nd:YAG) alone. Secondarily, to evaluate QoL impairment in HHT patients, and its improvement with laser therapy.

METHODS

A comparative randomized split-body double-blinded prospective study (DWSL vs Nd:YAG). Demographic, clinical and treatment characteristics were recorded. The severity and degree of improvement were evaluated by three blinded examiners who scored pre-treatment and post-treatment pictures on a 5-point scale. Patients fulfilled Skindex-29 and FACE-Q® tests and assessed procedure-associated pain and patient satisfaction.

RESULTS

111 treatment areas (55 treated with DWSL and 56 with Nd:YAG) from 26 patients were analyzed. The median number of laser sessions was 2 (interquartile range [IQR] 2-4; mean 2.90 vs 2.88, respectively). The median improvement score, irrespective of location, was significantly higher for Nd:YAG compared to DWSL: 3 (IQR 2-3; mean 2.61) vs 2 (IQR 2-3; mean 2.32), p=0.031. Both FACE-Q index and Skindex-29 test results improved significantly (p<0.001), and 92.4% patients reported a high degree of satisfaction (≥8). No severe adverse events were reported.

CONCLUSIONS

DWSL and Nd:YAG laser are convenient, safe and effective treatment options for mucocutaneous telangiectases in HHT patients. However, Nd:YAG delivered better results with better tolerability. QoL was significantly improved by both treatments.

Comparative Treatment of Mucocutaneous Lesions in Hereditary Haemorrhagic Telangiectasia Patients With Dual Sequential Pulsed Dye Laser and Neodymium: Yttrium-Aluminium-Garnet Versus Neodymium: Yttrium-Aluminium-Garnet Laser Alone: A Double-Blind Randomized Controlled Study With Quality-of-Life Evaluation

BACKGROUND

Hereditary haemorrhagic telangiectasia (HHT) is characterized by the presence of telangiectases and larger arteriovenous malformations in different organs. Mucocutaneous telangiectases can bleed and become an aesthetic concern, impairing quality of life (QoL). However, the best treatment approach has not been defined yet.

OBJECTIVE

To evaluate the efficacy and safety of dual wavelength sequential 595/1064nm laser (DWSL) compared to 1064nm laser (Nd:YAG) alone. Secondarily, to evaluate QoL impairment in HHT patients, and its improvement with laser therapy.

METHODS

A comparative randomized split-body double-blinded prospective study (DWSL vs Nd:YAG). Demographic, clinical and treatment characteristics were recorded. The severity and degree of improvement were evaluated by three blinded examiners who scored pre-treatment and post-treatment pictures on a 5-point scale. Patients fulfilled Skindex-29 and FACE-Q® tests and assessed procedure-associated pain and patient satisfaction.

RESULTS

111 treatment areas (55 treated with DWSL and 56 with Nd:YAG) from 26 patients were analyzed. The median number of laser sessions was 2 (interquartile range [IQR] 2-4; mean 2.90 vs 2.88, respectively). The median improvement score, irrespective of location, was significantly higher for Nd:YAG compared to DWSL: 3 (IQR 2-3; mean 2.61) vs 2 (IQR 2-3; mean 2.32), p=0.031. Both FACE-Q index and Skindex-29 test results improved significantly (p<0.001), and 92.4% patients reported a high degree of satisfaction (≥8). No severe adverse events were reported.

CONCLUSIONS

DWSL and Nd:YAG laser are convenient, safe and effective treatment options for mucocutaneous telangiectases in HHT patients. However, Nd:YAG delivered better results with better tolerability. QoL was significantly improved by both treatments.

Potential angiogenic biomarkers in hereditary hemorrhagic telangiectasia and other vascular diseases

Biomarkers are new tools framed in precision and personalized medicine. Hereditary hemorrhagic telangiectasia (HHT) is a rare genetic vascular disease with disturbances in the angiogenic pathways. Descriptive evidence supports that some angiogenesis-related molecules are differently detected in HHT patients compared to healthy subjects. These molecules are also related to diagnosis, prognosis, complications and therapy monitoring in other common vascular diseases. Despite the need for improving knowledge before applying them in daily clinical practice, there are good candidates to be considered as potential biomarkers in HHT and other vascular diseases. In the present review, the authors aim to summarize and discuss current evidence regarding the main putative angiogenic biomarkers by describing the biological role of each biomarker, the evidence related to HHT and their potential use in this and other common vascular diseases from a clinical point-of-view.

Highly dense linkage maps from 31 full-sibling families of turbot (Scophthalmus maximus) provide insights into recombination patterns and chromosome rearrangements throughout a newly refined genome assembly

Highly dense linkage maps enable positioning thousands of landmarks useful for anchoring the whole genome and for analysing genome properties. Turbot is the most important cultured flatfish worldwide and breeding programs in the fifth generation of selection are targeted to improve growth rate, obtain disease resistant broodstock and understand sex determination to control sex ratio. Using a Restriction-site Associated DNA approach, we genotyped 18,214 single nucleotide polymorphism in 1,268 turbot individuals from 31 full-sibling families. Individual linkage maps were combined to obtain a male, female and species consensus maps. The turbot consensus map contained 11,845 markers distributed across 22 linkage groups representing a total normalised length of 3,753.9 cM. The turbot genome was anchored to this map, and scaffolds representing 96% of the assembly were ordered and oriented to obtain the expected 22 megascaffolds according to its karyotype. Recombination rate was lower in males, especially around centromeres, and pairwise comparison of 44 individual maps suggested chromosome polymorphism at specific genomic regions. Genome comparison across flatfish provided new evidence on karyotype reorganisations occurring across the evolution of this fish group.

Accuracy of genomic within-family selection in aquaculture breeding programmes

In aquaculture breeding programmes, selection within families cannot be applied for traits that cannot be recorded on the candidates (e.g., disease resistance or fillet quality). However, this problem can be overcome if genomic evaluation is used. Within-family genomic evaluation has been proposed for these programmes as large family sizes are available and substantial levels of linkage disequilibrium (LD) within families can be attained with a limited number of markers even in populations in global linkage equilibrium. Here, we compare by computer simulation: (i) within-family and population-wide LD; and (ii) the accuracy of within-family genomic selection when genomic evaluations are carried out either at the population level or within families. The population simulated was composed by a varying number of families of full-sibs (half for training and half for testing). The results indicate that, to practice within-family selection, performing the genomic evaluation separately for each family using only molecular information from the family could be recommended for populations either in linkage equilibrium or with a low level of disequilibrium.

The use of coancestry based on shared segments for maintaining genetic diversity

We have evaluated the use of genomic coancestry coefficients based on shared segments for the maintenance of genetic diversity through optimal contributions methodology for populations of three different Austrian cattle breeds. This coancestry measure has been compared with the genomic coancestry coefficient calculated on a SNP-by-SNP basis and with pedigree-based coancestry. The regressions of the shared segments coancestry on the other two coefficients suggest that the former mainly reflect Identity By Descent but with the advantage over pedigree-based coancestry of providing the realized Identity By Descent rather than an expectation. The effective population size estimated from the rate of coancestry based on shared segments was very similar to those obtained with the other coefficients and of small magnitude (from 26.24 to 111.90). This result highlights the importance of implementing active management strategies to control the increase of inbreeding and the loss of genetic diversity in livestock breeds, even when the population size is reasonably large. One problem for the implementation of coancestry based on shared segments is the need of estimating the gametic phases of the SNPs which, given the techniques used to obtain the genotypes, are a priori unknown. This study shows, through computer simulations, that using estimates of gametic phases for computing coancestry based on shared segments does not lead to a significant loss in the diversity maintained. This has been shown to be true even when the size of the population is very small as it is usually the case in populations subjected to conservation programmes.

Copy number variants in a highly inbred Iberian porcine strain

We carried out a comprehensive genomic analysis of porcine copy number variants (CNVs) based on whole-genome SNP genotyping data and provided new measures of genomic diversity (number, length and distribution of CNV events) for a highly inbred strain (the Guadyerbas strain). This strain represents one of the most ancient surviving populations of the Iberian breed, and it is currently in serious danger of extinction. CNV detection was conducted on the complete Guadyerbas population, adjusted for genomic waves, and used strict quality criteria, pedigree information and the latest porcine genome annotation. The analysis led to the detection of 65 CNV regions (CNVRs). These regions cover 0.33% of the autosomal genome of this particular strain. Twenty-nine of these CNVRs were identified here for the first time. The relatively low number of detected CNVRs is in line with the low variability and high inbreeding estimated previously for this Iberian strain using pedigree, microsatellite or SNP data. A comparison across different porcine studies has revealed that more than half of these regions overlap with previously identified CNVRs or multicopy regions. Also, a preliminary analysis of CNV detection using whole-genome sequence data for four Guadyerbas pigs showed overlapping for 16 of the CNVRs, supporting their reliability. Some of the identified CNVRs contain relevant functional genes (e.g., the SCD and USP15 genes), which are worth being further investigated because of their importance in determining the quality of Iberian pig products. The CNVR data generated could be useful for improving the porcine genome annotation.

Malignant thyroid teratoma: report of an aggressive tumor in a 64-year-old man

Malignant teratoma of the thyroid is a rare and aggressive tumor, frequent in children than in adults. Histologically, thyroid teratomas usually show a predominance of a neuroectodermal component. Mature cartilage and bone may be present. We present the case of primary malignant teratoma of the thyroid in a 64-year-old man. Histologically, the tumor displayed a predominant neuroectodermal component. The diagnosis was confirmed by immunohistochemistry. The patient underwent a radical thyroidectomy with central neck dissection as primary treatment and radioiodine treatment afterwards. The patient had local and distant recurrence. A second surgery was performed with poor results and the patient died 3 months afterwards.

Accuracy of genome-wide evaluation for disease resistance in aquaculture breeding programs

Current aquaculture breeding programs aimed at improving resistance to diseases are based on challenge tests, where performance is recorded on sibs of candidates to selection, and on selection between families. Genome-wide evaluation (GWE) of breeding values offers new opportunities for using variation within families when dealing with such traits. However, up-to-date studies on GWE in aquaculture programs have only considered continuous traits. The objectives of this study were to extend GWE methodology, in particular the Bayes B method, to analyze dichotomous traits such as resistance to disease, and to quantify, through computer simulation, the accuracy of GWE for disease resistance in aquaculture sib-based programs, using the methodology developed. Two heritabilities (0.1 and 0.3) and 2 disease prevalences (0.1 and 0.5) were assumed in the simulations. We followed the threshold liability model, which assumes that there is an underlying variable (liability) with a continuous distribution and assumed a BayesB model for the liabilities. It was shown that the threshold liability model used fits very well with the BayesB model of GWE. The advantage of using the threshold model was clear when dealing with disease resistance dichotomous phenotypes, particularly under the conditions where linear models are less appropriate (low heritability and disease prevalence). In the testing set (where individuals are genotyped but not measured), the increase in accuracy for the simulated schemes when using the threshold model ranged from 4 (for heritability equal to 0.3 and prevalence equal to 0.5) to 16% (for heritability and prevalence equal to 0.1) when compared with the linear model.

Scrapie-resistant sheep show certain coat colour characteristics

Susceptibility to scrapie is known to be associated with polymorphisms at the prion protein (PrP) gene, and this association is the basis of current selective programmes implemented to control scrapie in many countries. However, these programmes might have unintended consequences for other traits that might be associated with PrP genotype. The objective of this study was to investigate the relationship between PrP genotype and coat colour characteristics in two UK native sheep breeds valued for their distinctive coat colour patterns. Coat colour pattern, darkness and spotting and PrP genotype records were available for 11 674 Badgerfaced Welsh Mountain and 2338 Shetland sheep. The data were analysed with a log-linear model using maximum likelihood. Results showed a strong significant association of PrP genotype with coat colour pattern in Badgerfaced Welsh Mountain and Shetland sheep and with the presence of white spotting in Shetland sheep. Animals with the ARR/ARR genotype (the most scrapie resistant) had higher odds of having a light dorsum and a dark abdomen than the reverse pattern. The implication of these associations is that selection to increase resistance to scrapie based only on PrP genotype could result in change in morphological diversity and affect other associated traits such as fitness.

Consequences of selection for improving production traits on the frequency of deleterious alleles for fitness

In this study the effect of artificial selection on BLUP EBV for production traits on the allele frequencies of a pleiotropic QTL affecting both production and disease susceptibility was investigated. Stochastic simulations were used to model artificial selection on a production trait that is controlled, in part, by a biallelic QTL that also controls susceptibility to disease. The QTL allele increasing production also increased susceptibility to disease. Different modes of action and proportions of variation accounted for by the QTL were assessed for the production trait. The main results indicated that alleles that confer susceptibility to the disease could be maintained in the population over a long period, depending on the mode of action of the QTL. In addition, the results of the study indicate that, under various conditions, it is possible to find pleiotropic QTL that control 2 traits despite these traits appearing to be uncorrelated. Therefore, in practice, an estimate of the genetic correlation between 2 traits may be misleading when the presence of such a QTL exists. The results of this study have implications for breeding programs. For example, if a pleiotropic QTL exists that favors heterozygotes for a production trait, it would be very difficult to remove disease susceptibility alleles via traditional selection methods.

Inbreeding in genome-wide selection

Traditional selection methods, such as sib and best linear unbiased prediction (BLUP) selection, which increased genetic gain by increasing accuracy of evaluation have also led to an increased rate of inbreeding per generation (DeltaFG). This is not necessarily the case with genome-wide selection, which also increases genetic gain by increasing accuracy. This paper explains why genome-wide selection reduces DeltaFG when compared with sib and BLUP selection. Genome-wide selection achieves high accuracies of estimated breeding values through better prediction of the Mendelian sampling term component of breeding values. This increases differentiation between sibs and reduces coselection of sibs and DeltaFG. The high accuracy of genome-wide selection is expected to reduce the between family variance and reweigh the emphasis of estimated breeding values of individuals towards the Mendelian sampling term. Moreover, estimation induced intraclass correlations of sibs are expected to be lower in genome-wide selection leading to a further decrease of coselection of sibs when compared with BLUP. Genome-wide prediction of breeding values, therefore, enables increased genetic gain while at the same time reducing DeltaFG when compared with sib and BLUP selection.

A critical review of adaptive genetic variation in Atlantic salmon: implications for conservation

Here we critically review the scale and extent of adaptive genetic variation in Atlantic salmon (Salmo salar L.), an important model system in evolutionary and conservation biology that provides fundamental insights into population persistence, adaptive response and the effects of anthropogenic change. We consider the process of adaptation as the end product of natural selection, one that can best be viewed as the degree of matching between phenotype and environment. We recognise three potential sources of adaptive variation: heritable variation in phenotypic traits related to fitness, variation at the molecular level in genes influenced by selection, and variation in the way genes interact with the environment to produce phenotypes of varying plasticity. Of all phenotypic traits examined, variation in body size (or in correlated characters such as growth rates, age of seaward migration or age at sexual maturity) generally shows the highest heritability, as well as a strong effect on fitness. Thus, body size in Atlantic salmon tends to be positively correlated with freshwater and marine survival, as well as with fecundity, egg size, reproductive success, and offspring survival. By contrast, the fitness implications of variation in behavioural traits such as aggression, sheltering behaviour, or timing of migration are largely unknown. The adaptive significance of molecular variation in salmonids is also scant and largely circumstantial, despite extensive molecular screening on these species. Adaptive variation can result in local adaptations (LA) when, among other necessary conditions, populations live in patchy environments, exchange few or no migrants, and are subjected to differential selective pressures. Evidence for LA in Atlantic salmon is indirect and comes mostly from ecological correlates in fitness-related traits, the failure of many translocations, the poor performance of domesticated stocks, results of a few common-garden experiments (where different populations were raised in a common environment in an attempt to dissociate heritable from environmentally induced phenotypic variation), and the pattern of inherited resistance to some parasites and diseases. Genotype x environment interactions occurr for many fitness traits, suggesting that LA might be important. However, the scale and extent of adaptive variation remains poorly understood and probably varies, depending on habitat heterogeneity, environmental stability and the relative roles of selection and drift. As maladaptation often results from phenotype-environment mismatch, we argue that acting as if populations are not locally adapted carries a much greater risk of mismanagement than acting under the assumption for local adaptations when there are none. As such, an evolutionary approach to salmon conservation is required, aimed at maintaining the conditions necessary for natural selection to operate most efficiently and unhindered. This may require minimising alterations to native genotypes and habitats to which populations have likely become adapted, but also allowing for population size to reach or extend beyond carrying capacity to encourage competition and other sources of natural mortality.

Associations of PrP genotypes with live weight and slaughter traits in an experimental flock of Swaledale sheep in Great Britain

Polymorphisms at codons 136, 154 and 171 of the gene encoding the prion protein (PrP) are associated with susceptibility to classical scrapie in sheep. Genetic selection for scrapie resistance based on PrP genotypes is central to the scrapie eradication programme in Great Britain but there are concerns about how this may affect other economically important traits. The objective of this study was to evaluate associations of PrP genotypes with live weight and slaughter traits in a hill sheep breed in Great Britain. Data used were from an experimental flock of Swaledale sheep in which the alleles ARR, ARQ, AHQ and VRQ were present. About 1450 genotyped lambs with birth, marking and weaning weights, and 620 with slaughter records were used for the study. Mixed models with various fixed effects and random direct genetic and maternal effects were tested to determine the appropriate model to use for each trait. None of the differences in lamb performance between PrP genotypes consistently reached significance. Therefore, this study does not support existence of significant relationships between PrP genotype and lamb performance traits in this breed.

Associations of polymorphisms of the ovine prion protein gene with growth, carcass, and computerized tomography traits in Scottish Blackface lambs

The objective of this study was to investigate and estimate the associations of the ovine prion protein (PrP) genotypes with a wide range of performance traits in Scottish Blackface lambs. Performance records of up to 7,138 sheep of known PrP genotypes born from 1999 to 2004 in 2 experimental farms were utilized. Performance traits studied were BW at birth, marking (when the sheep were identified with permanent ear tags at an average age of 52 d), and weaning (average age of 107 d); slaughter traits (BW at slaughter, slaughter age, carcass weight, and carcass conformation); ultrasonic muscle and fat depths; and computerized tomography-predicted carcass composition and carcass yield at weaning. Different linear mixed models, including random, direct animal effect, and up to 3 maternal effects (genetic, permanent, and temporary environmental) were used for the different traits. The PrP genotype was included in the model as a fixed effect, along with other fixed factors with significant effects (P < 0.05). Five separate analyses were carried out for each trait, differing in the method of PrP genotypic classification. The first analysis was based on classifying the sheep into categories according to all 9 available PrP genotypes. In the other 4 analyses, sheep were categorized according to the number of each PrP allele carried. Results showed that there were no significant differences between PrP genotypes for any of the performance traits studied when all 9 genotypes were compared (first analysis). Similarly, performance of the lambs did not significantly differ between genotypes with different numbers of ARR copies. However, there were significant variations in a few traits with respect to the number of ARQ, AHQ, and VRQ alleles carried. Heterozygous lambs for the AHQ or the ARQ allele were significantly heavier at some ages than lambs of the other genotypes. Lambs carrying the VRQ allele required approximately 10 d longer finishing time (P = 0.01) and yielded carcasses approximately 0.5 kg heavier (P = 0.03) compared with noncarriers. The few significant associations found do not have a negative influence on performance when selecting against the most susceptible PrP allele (VRQ) or in favor of the most resistant one (ARR). Overall, there were no major associations of PrP genotypes with most lamb performance traits in Scottish Blackface sheep.

Prediction of accuracy of estimated Mendelian sampling terms

This study describes a general framework for predicting the accuracy of Mendelian sampling terms when truncation selection is applied on best linear unbiased prediction (BLUP) estimated breeding values. A selection index approach is followed. The pseudo-BLUP index is extended to include terms related to the Mendelian sampling term. Predicted accuracies are compared with those obtained through stochastic computer simulation. Good predictions for the accuracy of the Mendelian sampling term were obtained both at selection time and at convergence of long-term contributions of selected candidates for a range of heritabilities and population structures. The prediction approach developed provides a key tool for obtaining predictions of genetic response from quadratic optimization that maximizes the rate of genetic progress while restricting the rate of inbreeding.

Cumulative Discounted Expressions of Sire Genotypes for the Complex Vertebral Malformation and β-Casein Loci in Commercial Dairy Herds

Based on discounted gene-flow principles, a set of recursive equations was developed to quantify the value of using sires with a specific genotype for an identified gene in a commercial dairy herd. Two examples were used to demonstrate the usefulness of the method. The first example deals with the implications of using sires that are known carriers of the lethal recessive genetic defect, complex vertebral malformation (CVM). The second example examines the value of using sires homozygous for the A2 allele of beta-casein. Results are presented in terms of cumulative discounted expressions. These are then multiplied by the economic values of specific genotypes to determine the cost or benefit of using these sires. In general, the degree of mortality and the required price reduction for carrier sires increased as the proportion of carrier sires used, the duration of sire use, and the initial frequency in the cow herd increased. A semen discount of 3.10 pound sterling per CVM straw used would be required to offset the expected mortality when 20% of CVM carrier sires are used for 3 yr when 5% of cows are carriers. The cumulative discounted expressions' of using sires homozygous for the A2 allele of beta-casein also increased when the proportion and duration of carrier sire use and the initial frequency of the A2 allele increased. Assuming an A2A2 cow is worth 160 pound sterling more than a non-A2A2 cow, the expected benefit of using A2A2 sires in a 100-cow herd for 5 yr would be 57 pound sterling,120 for a 20-yr planning horizon. The results of this study demonstrate how the starting gene frequency in the herd, and the proportion and duration of use of sires of particular genotypes are critical to the economic implications of using single genes in commercial dairy farms.

Benefits from marker-assisted selection under an additive polygenic genetic model1

This study investigated, through stochastic computer simulation, the extra gains expected from marker-assisted selection (MAS) in an infinitesimal model with linkage. The trait under selection was assumed to be controlled by 2,000 loci of additive small effect and evenly distributed in c chromosomes of one Morgan each (and c = 5, 10, 20, or 30). This approach differs from previous studies on the benefits of MAS that have considered mixed inheritance models. Marker information was used together with pedigree information to compute the relationship matrix used in BLUP genetic evaluations. The MAS schemes were compared with schemes where genetic evaluations were performed using standard BLUP (i.e., the relationship matrix is obtained using pedigree information only). When the number of markers was large enough (approximately one marker every 10 cM), there were increases in the accuracy of selection with MAS, and this led to extra gains compared with standard BLUP for all genome sizes considered. The benefit from MAS increased over generations. At the last generation of selection (Generation 10), the response from MAS was 11, 9, 7, and 5% greater than with standard BLUP for genomes with 5, 10, 20, and 30 chromosomes, respectively. Thus, although small, gains from MAS were nonetheless detectable for genome sizes typical of livestock populations.

Maximizing genetic gain over multiple generations with quantitative trait locus selection and control of inbreeding

Stochastic computer simulation was used to investigate the potential extra genetic gains obtained from gene-assisted selection (GAS) by combining 1) optimization of genetic contributions for maximizing gain, while restricting the rate of inbreeding with 2) optimization of the relative emphasis given to the QTL over generations. The genetic model assumed implied a mixed inheritance model in which a single quantitative trait locus (i.e., QTL) is segregating together with polygenes. When compared with standard GAS (i.e., fixed contributions and equal emphasis on the QTL and polygenic EBV), combined optimization of contributions of selection candidates and weights on the QTL across generations allowed substantial increases in gain at a fixed rate of inbreeding and avoided the conflict between short- and long-term responses in GAS schemes. Most of the increase of gain was produced by optimization of selection candidates' contributions. Optimization of the relative emphasis given to the QTL over generations had, however, a greater effect on avoiding the long-term loss usually observed in GAS schemes. Optimized contribution schemes led to lower gametic phase disequilibrium between the QTL and polygenes and to higher selection intensities both on the QTL and polygenes than with standard truncation selection with fixed contributions of selection candidates.

Inbreeding Trends and Application of Optimized Selection in the UK Holstein Population

Important increases in the rates of inbreeding have recently been observed in dairy cattle populations, and methods have been proposed to address these increases. The aims of this study were to estimate the current level and rates of inbreeding in the UK Holstein population and to investigate the potential of applying optimized selection to manage the rates of inbreeding. Inbreeding coefficients were calculated for the entire UK Holstein population using 1940 as the base year. Rates of inbreeding were obtained for 3 time periods by regressing mean inbreeding coefficients on the year of birth of the animals. The expected average pedigree index and expected inbreeding of offspring using optimized contributions for a given set of selection candidates was compared to the expected pedigree index and inbreeding of offspring for the same set of selection candidates using observed contributions. The rate of inbreeding in the UK Holstein population has increased substantially since 1990 when compared to previous time periods. This increase is most likely due to the large influence of a few related sires on the breed in the mid- to late 1980s. The introduction of the individual animal model in the early 1990s may also have contributed to increased inbreeding. Optimized selection appears to represent a promising selection tool, not only to manage rates of inbreeding, but also to increase genetic gain at the same rate of inbreeding.

Mendelian sampling terms as a selective advantage in optimum breeding schemes with restrictions on the rate of inbreeding

Quadratic indices are a general approach for the joint management of genetic gain and inbreeding in artificial selection programmes. They provide the optimal contributions that selection candidates should have to obtain the maximum gain when the rate of inbreeding is constrained to a predefined value. This study shows that, when using quadratic indices, the selective advantage is a function of the Mendelian sampling terms. That is, at all times, contributions of selected candidates are allocated according to the best available information about their Mendelian sampling terms (i.e. about their superiority over their parental average) and not on their breeding values. By contrast, under standard truncation selection, both estimated breeding values and Mendelian sampling terms play a major role in determining contributions. A measure of the effectiveness of using genetic variation to achieve genetic gain is presented and benchmark values of 0.92 for quadratic optimisation and 0.5 for truncation selection are found for a rate of inbreeding of 0.01 and a heritability of 0.25.

Optimal mass selection policies for schemes with overlapping generations and restricted inbreeding

Optimum breeding schemes for maximising the rate of genetic progress with a restriction on the rate of inbreeding (per year or per generation) are investigated for populations with overlapping generations undergoing mass selection. The optimisation is for the numbers of males and females to be selected and for their distribution over age classes. Expected rates of genetic progress (DeltaG) are combined with expected rates of inbreeding (DeltaF) in a linear objective function (Phi = DeltaG - lambdaDeltaF) which is maximised. A simulated annealing algorithm is used to obtain the solutions. The restriction on inbreeding is achieved by increasing the number of parents and, in small schemes with severe restrictions, by increasing the generation interval. In the latter case the optimum strategy for obtaining the maximum genetic gain is far from truncation selection across age classes. In most situations, the optimum mating ratio is one but the differences in genetic gain obtained with different mating ratios are small. Optimisation of schemes when restricting the rate of inbreeding per generation leads to shorter generation intervals than optimisation when restricting the rate of inbreeding per year.

Expected increases in genetic merit from using optimized contributions in two livestock populations of beef cattle and sheep1

The expected benefits from optimized selection in real livestock populations were evaluated by applying dynamic selection algorithms to two livestock populations of sheep (Meatlinc) and beef cattle (Aberdeen Angus). In addition, the effects of introducing BLUP evaluations on the population structure, genetic gain, and inbreeding were investigated. The use of BLUP-EBV accelerated the rates of gain in the Meatlinc, but the effects of BLUP evaluations on Aberdeen Angus are not as evident. Although steady increases in the average coefficient of inbreeding (F) were observed, the inbreeding rates (deltaF) before and after the introduction of BLUP evaluations were not significantly different. The observed deltaF in the last generation was 1.0% for Meatlinc and 0.2% for Aberdeen Angus. The application of the dynamic selection algorithms for maximizing genetic gain at a fixed deltaF led to important expected increases in the rate of genetic gain (deltaG). When deltaF was restricted to the value observed in both populations, increments per year in deltaG of 4.6 (i.e., 17%) index units for Meatlinc and 3.5 (i.e., 30%) index units for Aberdeen Angus were found in comparison to the deltaG expected from conventional truncation BLUP selection. More relaxed constraints on deltaF allowed even higher expected increases in deltaG in both populations. This study demonstrates that the optimization tools constitute a potentially highly effective way of managing gain and inbreeding under a broad range of schemes in terms of scale and inbreeding level. No losses in genetic gain were associated with the use of dynamic optimization selection when schemes were compared at the same deltaF.

[Exoftalmos and palpebral ptosis in the immunocompromised patient]

The mucormycosis is an opportunistic mycosis which has a high rate of global mortality with a bad prognosis. The present clinical case shows a patient attended in the Intensive Care Unit because of a breathing insufficiency secondary to a pneumonia. Among his antecedents there is a larynx carcinoma totally remittent after chemo- and radiotherapy. He develops an infrapalpebral injury which spreads rapidly in a bilateral way acquiring a necrotic look that it did not have initially. Having that evolution, it is implemented a treatment with liposomal amphotericin B and granulocyte colony-stimulating factors after an injury biopsy, whose posterior cultive shows growing of Mucor. This kind of pathology must be initially suspected in all the patients with a neoplasia and its treatment must be early and agressive. At the moment the diagnosis is suspected there is a great tissue destruction and for that reason the patients usually die in spite of the instauration of aggressive therapies

Parental assignment in fish using microsatellite genetic markers with finite numbers of parents and offspring

Deterministic predictions for the proportion of offspring assigned to different numbers of parent-pairs are developed in order to investigate the power of microsatellite loci for parental assignment in fish species. Comparisons with stochastic simulation results show that predictions based on exclusion probabilities are accurate, provided that the number of parents involved in the crosses is large. Accounting for sampling of parents gave very accurate predictions for a small number of parents and a single biallelic locus. For large numbers of loci or large numbers of alleles per locus stochastic simulations are, however, the only available method to predict the power of assignment of a particular set of loci when the number of parents is small. Nine 5-allele loci or six 10-allele loci with equifrequent alleles, are sufficient for assigning, with certainty, parents to 99% of the fish resulting from either 100 or 400 crosses. Results simulating a set of highly polymorphic microsatellites developed for Atlantic salmon show that the four most informative loci are sufficient to assign at least 99% of the offspring to the correct pair with 100 crosses involving 100 males and 100 females. An additional locus is required for correctly assigning 99% of the offspring when the 100 crosses are produced with 10 males and 10 females.

Synthesis of direct and maternal genetic components of economically important traits from beef breed-cross evaluations

Published information on relative performance of beef breed crosses was used to derive combined estimates of purebred breed values for predominant temperate beef breeds. The sources of information were largely from the United States, Canada, and New Zealand, although some European estimates were also included. Emphasis was on maternal traits of potential economic importance to the suckler beef production system, but some postweaning traits were also considered. The estimates were taken from comparison studies undertaken in the 1970s, 1980s and 1990s, each with representative samples of beef breeds used in temperate agriculture. Weighting factors for breed-cross estimates were derived using the number of sires and offspring that contributed to that estimate. These weights were then used in a weighted multiple regression analysis to obtain single purebred breed effects. Both direct additive and maternal additive genetic effects were estimated for preweaning traits. Important genetic differences between the breeds were shown for many of the traits. Significant regression coefficients were estimated for the effect of mature weight on calving ease, both maternal and direct additive genetic, survival to weaning direct, and birth weight direct. The breeds with greater mature weight were found to have greater maternal genetic effects for calving ease but negative direct genetic effects on calving ease. A negative effect of mature weight on the direct genetic effect of survival to weaning was observed. A cluster analysis was done using 17 breeds for which information existed on nine maternal traits. Regression was used to predict breed-cross-specific heterosis using genetic distance. Only five traits, birth weight, survival to weaning, cow fertility, and preweaning and postweaning growth rate had enough breed-cross-specific heterosis estimates to develop a prediction model. The breed biological values estimated provide a basis to predict the biological value of crossbred suckler cows and their offspring.

Expected genetic contributions and their impact on gene flow and genetic gain

Long-term genetic contributions (r(i)) measure lasting gene flow from an individual i. By accounting for linkage disequilibrium generated by selection both within and between breeding groups (categories), assuming the infinitesimal model, a general formula was derived for the expected contribution of ancestor i in category q (mu(i)(q)), given its selective advantages (s(i)(q)). Results were applied to overlapping generations and to a variety of modes of inheritance and selection indices. Genetic gain was related to the covariance between r(i) and the Mendelian sampling deviation (a(i)), thereby linking gain to pedigree development. When s(i)(q) includes a(i), gain was related to E[mu(i)(q))a(i)], decomposing it into components attributable to within and between families, within each category, for each element of s(i)(q). The formula for mu(i)(q) was consistent with previous index theory for predicting gain in discrete generations. For overlapping generations, accurate predictions of gene flow were obtained among and within categories in contrast to previous theory that gave qualitative errors among categories and no predictions within. The generation interval was defined as the period for which mu(i)(q), summed over all ancestors born in that period, equaled 1. Predictive accuracy was supported by simulation results for gain and contributions with sib-indices, BLUP selection, and selection with imprinted variation.

Index versus tandem selection after repeated generations of selection

A theoretical comparison between two multiple-trait selection methods, index and tandem selection, after several generations of selection was carried out. An infinite number of loci determining the traits, directional and truncation selection, discrete generations and infinite population size were assumed. Under these assumptions, changes in genetic parameters over generations are due to linkage disequilibrium generated by selection. Changes continue for several generations until equilibrium is approached. Algebraic expressions for asymptotic responses from index selection can be derived if index weights are maintained constant across generations. Expressions at equilibrium for genetic parameters and responses are given for the index and its component traits. The loss in response by using initial index weights throughout all generations, instead of updating them to account for changes in genetic parameters, was analyzed. The benefit of using optimum weights was very small ranging from 0% to about 1.5% for all cases studied. Recurrence formulae to predict genetic parameters and responses at each generation of selection are given for both index and tandem selection. A comparison between expected response in the aggregate genotype at equilibrium from index and tandem selection is made considering two traits of economic importance. The results indicate that although index selection is more efficient for improving the aggregate breeding value, its relative efficiency with respect to tandem selection decreases after repeated cycles of selection. The reduction in relative efficiency is highest with the highest selection intensity and heritabilities and with negative correlations between the two traits. The advantage of index over tandem selection might be further reduced if changes in genetic parameters due to gene frequency changes produced by selection, random fluctuations due to the finite size of the population, and errors in estimation of parameters, were also considered.

Asymmetrical correlated responses to selection under an infinitesimal genetic model

Asymmetry in correlated responses to selection is expected when more than one cycle of selection is practised due to changes in genetic parameters produced by selection. In large populations, under the infinitesimal model these changes are due to linkage disequilibrium generated by selection and not to gene frequency changes. This study examines the conditions under which asymmetrical correlated responses are to be expected when an infinitesimal model is considered. Asymmetrical correlated responses in two traits in respect to which trait is selected are expected if the two traits have different heritabilities. Predicted asymmetry increases with the absolute value of the genetic correlation between the two traits, the difference between the two heritabilities, the intensity of selection and the number of generations of selection. Linkage disequilibrium generated by selection should be taken into account in explaining asymmetrical correlated responses observed in selection experiments.

Effect of controlled ovarian hyperstimulation on pregnancy rates after intrauterine insemination

OBJECTIVE

Our objective was to evaluate the effect of controlled ovarian hyperstimulation on pregnancy rates after intrauterine insemination of washed husband's sperm.

STUDY DESIGN

In a private practice setting at the Infertility, Gynecology, and Obstetrics Medical Group in San Diego, 79 treatment programs included intrauterine insemination during natural cycles, 195 included clomiphene stimulation, and 53 had human menopausal gonadotropin stimulation. Pregnancy rates and monthly fecundabilities were calculated by life-table analysis and compared by the Z test.

RESULTS

By life-table analysis the cumulative probability of pregnancy after intrauterine insemination with no ovulation induction is 21.0% after six cycles with a monthly fecundability of 3.4%. With clomiphene the pregnancy rate is 32.7% with a monthly fecundability of 6.1%, and with human menopausal gonadotropin the pregnancy rate is 60.7% with a monthly fecundability of 13.0%. The human menopausal gonadotropin group had a significantly higher pregnancy rate and monthly fecundability as compared with the other two groups. There were no differences between the no-stimulation and the clomiphene groups.

CONCLUSIONS

Human menopausal gonadotropin stimulation results in a significantly higher pregnancy rate and monthly fecundability after intrauterine insemination as compared with no stimulation or clomiphene use.

Efficiency of indirect selection at selection equilibrium

Efficiency of indirect selection compared with that of direct selection to increase the mean value of some trait has been usually studied by considering a single generation of indirect and direct responses to selection only. However, under continued selection, genetic variances and covariances, and therefore expected genetic responses, change each generation due to linkage disequilibrium. With directional and truncation selection, genetic parameters asymptote to limiting values after several generations. The efficiency of indirect selection is examined in this limiting situation. The ratio of correlated response to direct response for the trait to improve in the limit is compared with the ratio after the first generation of selection. For all initial parameter values for which indirect selection is more efficient than direct selection, relative efficiency of indirect selection is smaller in the limit than in the first generation. For some parameter values, indirect selection is more efficient than direct selection in the first generation, but less efficient in the limit. Expressions for minimum values of the initial genetic correlation and heritability of the alternative trait required for indirect selection to be preferred in the limit are derived. These values are higher when limiting responses are used instead of single generation responses. The loss in relative efficiency of indirect selection from changes in genetic parameters due to selection should be taken into account when applications of indirect selection are considered.

Effect of selection on genetic parameters of correlated traits

Changes in genetic parameters of correlated traits due to the buildup of linkage (gametic phase) disequilibrium from repeated truncation selection on a single trait are studied. After several generations of selection, an equilibrium is approached where there are no further changes in genetic parameters and limiting values are reached. Formulae are derived under an infinitesimal model for these limiting values of genetic variances and covariances, heritabilities, and genetic correlations between traits directly and indirectly selected. Changes from generation zero to the limit in all these parameters become greater as heritability of the trait under direct selection increases and, to a lesser extent, as intensity of selection increases. Change in heritability of a trait under indirect selection also increases as the absolute value of the correlation between the trait under indirect and the trait under direct selection increases. The change is maximum when the initial value of heritability is close to 0.5 and insignificant when the initital value is close to zero or one. Change in the genetic correlation between the trait under direct selection and the trait under indirect selection is maximum when its initial value is close to ±0.6 and insignificant when its initial value is close to zero or ±1. Heritability of the trait indirectly selected and genetic correlation between that trait and the trait directly selected always decrease in absolute value, whereas genetic correlation between two traits indirectly selected can either decrease or increase in absolute value. It is suggested that use be made of formulae at selection equilibrium in the prediction of correlated responses after several generations of selection.

Pregnancy rates with fresh versus computer-controlled cryopreserved semen for artificial insemination by donor in a private practice setting

From late 1970 through December 1987, 580 women began 733 treatment programs (a total of 3405 insemination cycles) with fresh semen for artificial insemination by donor. The unadjusted pregnancy rate was 48.5% and the cumulative pregnancy rate after seven cycles by life-table analysis was 59.6% with a monthly fecundability of 11.9%. From 1988 to the present, 113 women have begun 115 treatment programs (a total of 371 insemination cycles) with cryopreserved semen for artificial insemination by donor. The unadjusted pregnancy rate to date is 18.3% and the cumulative pregnancy rate after seven cycles by life-table analysis is 48.6% with a monthly fecundability of 5.9%. This report shows that using cryopreserved semen for artificial insemination by donor will take somewhat longer to produce a pregnancy but the ultimate pregnancy rate will be similar to that with fresh semen for artificial insemination by donor.

Experimental comparison of restricted selection index and restricted independent culling levels in Tribolium castaneum

A selection index (I) method was compared with independent culling levels (N), with a restriction in the selection program, using two replicated single generation experiments in Tribolium castaneum, which are considered forms of antagonistic selection. The first experiment was designed to increase adult weight without changing pupal weight, while the second experiment was intended to improve egg laying without changing adult weight. In both experiments the genetic correlation between the traits involved were positive but were higher in experiment 1 than in experiment 2. The proportion of selection was 10%. In experiment 1, the effect of restriction was as expected in both lines since the changes in pupal weight were not significant. Adult weight change was positive for the I line and negative for the N line, showing that the index was a superior method to improve adult weight. In experiment 2, the effect of restriction was also as expected in both lines and changes in adult weight were not significant. Egg laying changed positively in both lines. Therefore, both selection methods were similar in this experiment, even though egg laying change was higher in the I than the N line.

Key words: restricted index, restricted culling levels, antagonistic selection, Tribolium.

Results of microsurgical treatment of tubal infertility and early second-look laparoscopy in the post-pelvic inflammatory disease patient: implications for in vitro fertilization

Sixty-nine patients with tubal infertility secondary to pelvic inflammatory disease were surgically treated by one of three infertility surgeons, who used microsurgery for repair of the tubal pathologic condition and early second-look laparoscopy 6 to 30 days postoperatively for lysis of postoperative adhesions. No patient was included in this group whose disease was thought to have originated from endometriosis or prior abdominal surgery. The average follow-up time was 43.1 months (range 12 to 85.9). Nine patients were excluded from the analysis. Pregnancy outcome by procedure, expressed as the percentage of patients conceiving, was as follows: adhesiolysis, 69% (61% term, 8% ectopic); fimbrioplasty, 35% (25% term, 10% ectopic); salpingostomy, 30% (18% term, 12% ectopic); and cornual implantation, 60% (40% term, 20% ectopic). No added therapeutic value could be attributed to the use of early second-look laparoscopy. Given the relatively poor outcome of fimbrioplasty and salpingostomy, it may be prudent to advise patients with bilateral partial and/or total tubal occlusion against tuboplasty in favor of in vitro fertilization and embryo transfer.