Dent and Flint maize diversity panels reveal important genetic potential for increasing biomass production.

KEY MESSAGE: Genetic and phenotypic analysis of two complementary maize panels revealed an important variation for biomass yield. Flowering and biomass QTL were discovered by association mapping in both panels. The high whole plant biomass productivity of maize makes it a potential source of energy in animal feeding and biofuel production. The variability and the genetic determinism of traits related to biomass are poorly known. We analyzed two highly diverse panels of Dent and Flint lines representing complementary heterotic groups for Northern Europe. They were genotyped with the 50 k SNP-array and phenotyped as hybrids (crossed to a tester of the complementary pool) in a western European field trial network for traits related to flowering time, plant height, and biomass. The molecular information revealed to be a powerful tool for discovering different levels of structure and relatedness in both panels. This study revealed important variation and potential genetic progress for biomass production, even at constant precocity. Association mapping was run by combining genotypes and phenotypes in a mixed model with a random polygenic effect. This permitted the detection of significant associations, confirming height and flowering time quantitative trait loci (QTL) found in literature. Biomass yield QTL were detected in both panels but were unstable across the environments. Alternative kinship estimator only based on markers unlinked to the tested SNP increased the number of significant associations by around 40% with a satisfying control of the false positive rate. This study gave insights into the variability and the genetic architectures of biomass-related traits in Flint and Dent lines and suggests important potential of these two pools for breeding high biomass yielding hybrid varieties.

A comparison of botulinum toxin a and intralesional steroids for the treatment of plantar fasciitis: a randomized, double-blinded study.

BACKGROUND: The objective of this study was to compare intramuscularly applied botulinum toxin A (BTX-A) in the gastroc-soleus complex with intralesional steroids for the treatment of plantar fasciitis. METHODS: The patients were randomly divided into 2 groups according to the treatment received. The patients were evaluated over 6 months. The evaluation scores included the Visual Analog Scale (VAS), Maryland Foot and Ankle, Foot and Ankle Disability Index (FADI), and American Orthopaedic Foot and Ankle Society (AOFAS) score. Moreover, patients were instructed to perform plantar fascia stretching exercises over the course of the study. The final number of patients was 36, of whom 19 received BTX-A (10 men and 9 women) and 17 (6 men and 11 women) received steroids. RESULTS: When compared to patients who received steroids, the patients who received BTX-A exhibited more rapid and sustained improvement over the duration of the study. CONCLUSION: A combination of BTX-A and plantar fascia stretching exercises yielded better results for the treatment of plantar fasciitis than intralesional steroids. LEVEL OF EVIDENCE: Level I, therapeutic studies.

Maximizing the reliability of genomic selection by optimizing the calibration set of reference individuals: comparison of methods in two diverse groups of maize inbreds (Zea mays L.).

Genomic selection refers to the use of genotypic information for predicting breeding values of selection candidates. A prediction formula is calibrated with the genotypes and phenotypes of reference individuals constituting the calibration set. The size and the composition of this set are essential parameters affecting the prediction reliabilities. The objective of this study was to maximize reliabilities by optimizing the calibration set. Different criteria based on the diversity or on the prediction error variance (PEV) derived from the realized additive relationship matrix-best linear unbiased predictions model (RA-BLUP) were used to select the reference individuals. For the latter, we considered the mean of the PEV of the contrasts between each selection candidate and the mean of the population (PEVmean) and the mean of the expected reliabilities of the same contrasts (CDmean). These criteria were tested with phenotypic data collected on two diversity panels of maize (Zea mays L.) genotyped with a 50k SNPs array. In the two panels, samples chosen based on CDmean gave higher reliabilities than random samples for various calibration set sizes. CDmean also appeared superior to PEVmean, which can be explained by the fact that it takes into account the reduction of variance due to the relatedness between individuals. Selected samples were close to optimality for a wide range of trait heritabilities, which suggests that the strategy presented here can efficiently sample subsets in panels of inbred lines. A script to optimize reference samples based on CDmean is available on request.

Efficiency of generations for estimating marker-associated QTL effects by multiple regression.

Knowledge about the efficiency of generations for estimating marker-associated QTLs is needed for selection. The objective of this paper is to develop a theory to compare the efficiency of segregating generations and testcrosses from the cross of two inbred lines differing in value for a quantitative trait (P1 x P2) for estimating additive, dominance and heterotic effects of QTLs by stepwise regression. An equation that predicts the smallest gene effect in genetic standard deviation units that can be detected with 50% chance at a significance level as a function of the heritability (h2) and the recombination frequency (r) of markers was developed for the segregating generations and testcrosses. For estimating additive effects, the most efficient generation was the doubled-haploid (DH) lines; the most inefficient was the North Carolina Design III (NCD III), followed by selfed backcrosses (SB); the selfed families from F2 individual plants (F2:3 lines) are inferior to the recombinant inbreds (RI) for low r, but are better than RI for high h2 and r. Dominance effects are less efficiently estimated than additive effects. The NCD III is better than the SB and the F2:3 lines for detecting dominance effects. The RI and DH do not estimate dominance effects. The differential heterotic QTL effects of lines P1 and P2 when crossed with tester T can be estimated by evaluating testcrosses of individual F2 plants (F2T), recombinant inbreds (RIT) and double-haploid lines (DHT). The DHT is superior to the other generations. The F2T is better than the RIT for r > or = 0.20, but inferior for r < or = 0.1 or low heritability.

Estimates of marker-associated QTL effects in Monte Carlo backcross generations using multiple regression.

The decision of whether or not to use QTLassociated markers in breeding programs needs further information about the magnitude of the additive and dominance effects that can be estimated. The objectives of this paper are (1) to apply some of the Moreno-Gonzalez (1993) genetic models to backcross simulation data generated by the Monte Carlo method, and (2) to get simulation information about the number of testing progenies and mapping density in relation to the magnitude of gene effect estimates. Results of the Monte Carlo study show that the stepwise regression analysis was able to detect relatively small additive and dominance effects when the QTL are independently segregating. When testing selfed families derived from backcross individuals, dominance effects had a larger error standard deviation and were estimated at a lower frequency. Linked QTL require a higher marker mapping density on the genome and a larger number of progenies to detect small genetic effects. Reduction of the environmental error variance by evaluating selfed backcross families in replicate experiments increased the power of the test. Expressions of the number of progenies for detecting significant additive effects were developed for some genetic situations. The ratio of the within-backcross genetic variance to the square of a gene effect estimate is a function of the number of progenies, the heritability of the trait, the marker map density and the portion of the genetic variance explained by the model. Different values (from 0 to 1) assigned to ρ (relative position of the QTL in the marker segment) did not cause a large shift in the residual mean square of the model.

Genetic models to estimate additive and non-additive effects of marker-associated QTL using multiple regression techniques.

The development of molecular markers has recently raised expectations for their application in selection programs. However, some questions related to quantitative trait loci (QTL) identification are still unanswered. The objectives of this paper are (1) to develop statistical genetic models for detecting and locating on the genome multi-QTL with additive, dominance and epistatic effects using multiple linear regression analysis in the backcross and Fn generations from the cross of two inbred lines; and (2) to discuss the bias caused by linked and unlinked QTL on the genetic estimates. Non-linear models were developed for different backcross and Fn generations when both epistasis and no epistasis were assumed. Generation analysis of marked progenies is suggested as a way of increasing the number of observations for the estimates without additional cost for molecular scoring. Some groups of progenies can be created in different generations from the same scored individuals. The non-linear models were transformed into approximate multivariate linear models to which combined stepwise and standard regression analysis could be applied. Expressions for the biases of the marker classes from linked QTL were obtained when no epistasis was assumed. When epistasis was assumed, these expressions increased in complexity, and the biases were caused by both linked and unlinked QTL.

[When to start orthodontic treatment]. / Cuándo comenzar un tratamiento de ortodoncia.

We are frequently ashed by patient and dentist what the best age is to begin orthodontic treatment. In this article we will try to classify what the best age to begin treatment is, according to the type of malocclusion.

A modified technique for excision of syringomas.

An easy, rapid, and inexpensive technique for excision of syringomas from eyelids is outlined, using a fine needle as a skin hook and a #11 scalpel blade and leaving superficial wounds for secondary closure. Possible advantages and disadvantages are discussed. We recommend this procedure as an effective alternative that provides good cosmetic results.

Spontaneous loss of permanent teeth: a case report.

Pathological root resorption has clinical symptoms of great importance when it appears in permanent teeth, as its etiology is not always clear. It is important to examine all local and general factors before determining its "idiopathic" cause. A case of spontaneous loss of permanent teeth in a 19 year-old female is presented. Through a meticulous study correlating the clinical history and the evolution of the symptoms, we can suspect that non-dental medical interventions requiring general anesthesia can lead to the loss of permanent teeth through root resorption.

Tooth eruption in children with growth deficit.

The authors aim to study the relation existing between the chronology of tooth eruption and delayed growth, whether this is delayed growth with or without low genetic height or delayed growth caused by growth hormone deficit. The 50 children included in the sample were studied from the endocrine and dental points of view and it was found that children whose delayed growth is accompanied by a low genetic height or growth hormone deficit presented retardation in dentition and retardation in bone age. However, a retardation in bone age does not necessarily imply a retardation in dentition.

Situaciones de urgencia del consultorio odontopediátrico

Para los odontólogos dedicados al tratamiento dental infantil, es necesario conocer los posibles riesgos de nuestra terapia, así como los accidentes que pueden ocurrir durante y después de realizada la misma. De esta manera, teniéndolos presentes, así como, conociendo los diferentes tratamientos para solucionar estas emergencias, podremos salvar a nuestro paciente de situaciones que van desde las más leves a aquellas que pueden incluso poner en peligro su vida

Choice of environments in reciprocal recurrent selection programs.

An alternative method of reciprocal recurrent selection (RRS) in which populations A and B are each evaluated in a different environment is proposed. This method is called dual-environment reciprocal recurrent selection (DERRS). Two genetic models are considered in the theoretical study. A comparison of selection methods shows that genetic gain is larger in DERRS than in RRS for the two models. The difference grows greater as the dominance effects operating in the two environments are more divergent and as the number of selection cycles increases. A greater gain is obtained when the genetic covariances between crosses in the two chosen environments are lower.

[Epidemiological profile of dental caries in Alcalá de Henares]. / Perfil epidemiológico de la caries dental en Alcalá de Henares.

This epidemiological study was carried out in order to know the buccal condition of 1,217 children aged between 5 and 15, in Alcalá de Henares, city whose social-economic and geographical characteristics are representative of the national average. The study has been made with data obtained by means of clinical and radiological exploration. The average results which have been found were 5.34 for co rate, 6.53 for the cos, 3.07 for the CAOD y 4.90 for the CAOS. The percentage of children with caries was 88.15%, almost an average of 5.13 caries per child.