Predictive ability of direct genomic values for lifetime net merit of Holstein sires using selected subsets of single nucleotide polymorphism markers

The objective of the present study was to assess the predictive ability of subsets of single nucleotide polymorphism (SNP) markers for development of low-cost, low-density genotyping assays in dairy cattle. Dense SNP genotypes of 4,703 Holstein bulls were provided by the USDA Agricultural Research Service. A subset of 3,305 bulls born from 1952 to 1998 was used to fit various models (training set), and a subset of 1,398 bulls born from 1999 to 2002 was used to evaluate their predictive ability (testing set). After editing, data included genotypes for 32,518 SNP and August 2003 and April 2008 predicted transmitting abilities (PTA) for lifetime net merit (LNM$), the latter resulting from progeny testing. The Bayesian least absolute shrinkage and selection operator method was used to regress August 2003 PTA on marker covariates in the training set to arrive at estimates of marker effects and direct genomic PTA. The coefficient of determination (R(2)) from regressing the April 2008 progeny test PTA of bulls in the testing set on their August 2003 direct genomic PTA was 0.375. Subsets of 300, 500, 750, 1,000, 1,250, 1,500, and 2,000 SNP were created by choosing equally spaced and highly ranked SNP, with the latter based on the absolute value of their estimated effects obtained from the training set. The SNP effects were re-estimated from the training set for each subset of SNP, and the 2008 progeny test PTA of bulls in the testing set were regressed on corresponding direct genomic PTA. The R(2) values for subsets of 300, 500, 750, 1,000, 1,250, 1,500, and 2,000 SNP with largest effects (evenly spaced SNP) were 0.184 (0.064), 0.236 (0.111), 0.269 (0.190), 0.289 (0.179), 0.307 (0.228), 0.313 (0.268), and 0.322 (0.291), respectively. These results indicate that a low-density assay comprising selected SNP could be a cost-effective alternative for selection decisions and that significant gains in predictive ability may be achieved by increasing the number of SNP allocated to such an assay from 300 or fewer to 1,000 or more.

Machine learning classification procedure for selecting SNPs in genomic selection: application to early mortality in broilers

Genome-wide association studies using single nucleotide polymorphisms (SNPs) can identify genetic variants related to complex traits. Typically thousands of SNPs are genotyped, whereas the number of phenotypes for which there is genomic information may be smaller. When predicting phenotypes, options for statistical model building range from incorporating all possible markers into the specification to including only sets of relevant SNPs (features). In the latter case, an efficient method of selecting influential features is required. A two-step feature selection method for binary traits was developed, which consisted of filtering (using information gain), and wrapping (using naïve Bayesian classification). The filter reduces the large number of SNPs to a much smaller size, to facilitate the wrapper step. As the procedure is tailored for discrete outcomes, an approach based on discretization of phenotypic values was developed, to enable feature selection in a classification framework. The method was applied to chick mortality rates (0-14 days of age) on progeny from 201 sires in a commercial broiler line, with the goal of identifying SNPs (over 5000) related to progeny mortality. To mimic a case-control study, sires were clustered into two groups, low and high, according to two arbitrarily chosen mortality rate cut points. By varying these thresholds, 11 different 'case-control' samples were formed, and the SNP selection procedure was applied to each sample. To compare the 11 sets of chosen SNPs, predicted residual sum of squares (PRESS) from a linear model was used. The two-step method improved naïve Bayesian classification accuracy over the case without feature selection (from around 50 to above 90% without and with feature selection in each case-control sample). The best case-control group (63 sires above or below the thresholds) had the smallest PRESS statistic among groups with model p-values below 0.003. The 17 SNPs selected using this group accounted for 31% of the variation in raw mortality rates between sire families.

Machine learning classification procedure for selecting SNPs in genomic selection: application to early mortality in broilers

In genome-wide association studies using single nucleotide polymorphisms (SNPs), typically thousands of SNPs are genotyped, whereas the number of phenotypes for which there is genomic information may be smaller. Atwo-step SNP (feature) selection method was developed, which consisted of filtering (using information gain), and wrapping (using naïve Bayesian classification). This was based on discretization of the continuous phenotypic values. The method was applied to chick early mortality rates (0-14 days of age) on progeny from 201 sires in a commercial broiler line, with the goal of identifying SNPs (over 5000) related to progeny mortality. Sires were clustered into two groups, low and high, according to two arbitrarily chosen mortality rate thresholds. By varying these thresholds, 11 different "case-control" samples were formed, and the SNP selection procedure was applied to each sample. To compare the 11 sets of chosen SNPs, predicted residual sum of squares (PRESS)from a linear model was used. Naive Bayesian classification accuracy was improved over the case without feature selection (from 50% to 90%). Seventeen SNPs in the best case-control group (with smallest PRESS) accounted for 31% of the variance among sire family mortality rates.

Relationship of pediatric overall performance category and pediatric cerebral performance category scores at pediatric intensive care unit discharge with outcome measures collected at hospital discharge and 1- and 6-month follow-up assessments

OBJECTIVE

Given the current focus on outcomes, there is a crucial need for easily utilized measures that can effectively quantify morbidity or disability after a child's critical illness or injury. The purpose of this study is to significantly extend the research on two such promising measures: the Pediatric Overall Performance Category (POPC) and the Pediatric Cerebral Performance Category (PCPC).

DESIGN

Cross-sectional analysis of a sample of pediatric intensive care unit (PICU) discharges and a prospective follow-up of this cohort of children.

SETTING

Arkansas Children's Hospital.

PATIENTS

Two hundred children (ranging in age from birth to 21 yrs) discharged from a PICU.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Data were collected at PICU discharge, hospital discharge, and 1- and 6-month follow-up assessments after hospital discharge. Measures utilized included the POPC (at PICU discharge), PCPC (at PICU discharge), Stanford-Binet Intelligence Scale, fourth edition (at hospital discharge), Bayley Scales of Infant Development, second edition (at hospital discharge), and the Vineland Adaptive Behavior Scales (at 1 and 6 months after discharge). Stanford-Binet Intelligence Quotients and Bayley Mental Developmental Index scores were significantly different across PCPC categories (p < .0001). Bayley Psychomotor Developmental Index scores and Vineland Adaptive Behavior Scales scores varied significantly across POPC categories (p < .0001). The test for linear trend was also significant for each of the comparisons.

CONCLUSIONS

The results of this study offer additional support for the use of the PCPC and POPC. These brief and easily completed measures can provide useful information regarding probable outcomes for pediatric intensive care patients when more extensive psychometric testing is not feasible or desirable.

Strong-willed children: a challenge to parents and pediatric dentists

Uncooperative behavior that is associated with a child being strong-willed is responsive to specific behavioral intervention strategies that have been extensively studied. These strategies are ones which are likely to be effective in the pediatric dental setting. We propose that these strategies are most effective when an integrative approach to strong-willed behavior is adopted by the pediatric dentist. Utilization of such an approach will reduce difficult child behavior, increase positive interactions between the dentist and child, and reduce parent frustration and concern.

Posttraumatic stress disorder and interpersonal functioning in Vietnam War veterans: a mediational model

This study examines the association between posttraumatic stress disorder (PTSD) and interpersonal functioning in a New Zealand community sample of 756 Vietnam War veterans. The results support previous research findings showing that PTSD adversely affects veterans' interpersonal relationships, family functioning, and marital/dyadic adjustment and show that the effects of PTSD on family functioning and dyadic adjustment are mediated by severity of interpersonal problems. It is suggested that higher levels of PTSD affect the ability of veterans to initiate and maintain interpersonal relationships and that these interpersonal problems are evident in poorer levels of family functioning and poorer dyadic adjustment.

Dose-rate effects of ethylene oxide exposure on developmental toxicity

In risk assessment, evaluating a health effect at a duration of exposure that is untested involves assuming that equivalent multiples of concentration (C) and duration (T) of exposure have the same effect. The limitations of this approach (attributed to F. Haber, Zur Geschichte des Gaskrieges [On the history of gas warfare], in Funf Vortrage aus den Jahren 1920-1923 [Five lectures from the years 1920-1923], 1924, Springer, Berlin, pp. 76-92), have been noted in several studies. The study presented in this paper was designed to specifically look at dose-rate (C x T) effects, and it forms an ideal case study to implement statistical models and to examine the statistical issues in risk assessment. Pregnant female C57BL/6J mice were exposed, on gestational day 7, to ethylene oxide (EtO) via inhalation for 1.5, 3, or 6 h at exposures that result in C x T multiples of 2100 or 2700 ppm-h. EtO was selected because of its short half-life, documented developmental toxicity, and relevance to exposures that occur in occupational settings. Concurrent experiments were run with animals exposed to air for similar periods. Statistical analysis using models developed to assess dose-rate effects revealed significant effects with respect to fetal death and resorptions, malformations, crown-to-rump length, and fetal weight. Animals exposed to short, high exposures of EtO on day 7 of gestation were found to have more adverse effects than animals exposed to the same C x T multiple but at longer, lower exposures. The implication for risk assessment is that applying Haber's Law could potentially lead to an underestimation of risk at a shorter duration of exposure and an overestimation of risk at a longer duration of exposure. Further research, toxicological and statistical, are required to understand the mechanism of the dose-rate effects, and how to incorporate the mechanistic information into the risk assessment decision process.

Gradual painless visual loss: chronic optic neuropathies

The clinician must be the ultimate medical detective when dealing with chronic optic neuropathies. History taking is crucial. Clinical examination may require supplementation with visual field testing, fluorescein angiography, ocular and orbital ultrasound imaging, CT and MR imaging, blood test data, and cerebrospinal fluid or tissue biopsy data to determine the specific diagnosis. This supplementation is labor-intensive and time-consuming; the visual loss usually will progress throughout the process, frustrating and frightening the patient and physician. The final common pathway is gradual optic atrophy; the appearance of the optic nerve is rarely adequate to determine the cause of the visual loss. This article includes tables that review diagnostic aids and therapies, and lists the frequency with which several disease entities were encountered over 15 years in one tertiary care neuro-ophthalmic practice. If a specific cause is discernible, then a specific therapy may be available. This approach has the best chance of saving the patient's vision with the least toxicity caused by erroneous trials. By necessity, the work-up for these patients is expensive, but the cost of not pursuing the cause is irrevocable, permanent blindness.

Mental health, physical health, and stressors reported by New Zealand Defence Force peacekeepers: a longitudinal study

The psychological effect of peacekeeping duties on 277 New Zealand Defence Force personnel was investigated using a longitudinal, cross-sectional study. Self-report data were collected in five stages from before deployment to approximately 6 months after return. Multiple measures of mental health, physical health, and stressors were used. Results revealed that the most stressful periods of the deployment, and those with the greatest effect on overall health and well-being, appear to be the predeployment and follow-up stages. These findings demonstrate the need for effective predeployment training and postdeployment debriefing and support.

Group hydrotherapy versus group land-based treatment for chronic low back pain

Sixty subjects with chronic low back pain (LBP) were sequentially allocated to either hydrotherapy treatment or land treatment groups in order of presentation. Subjects acted as their own controls for a period of three weeks, after which they attended their respective group sessions twice weekly for six weeks. Twenty-eight subjects from each group attended all treatment and assessment sessions. Results indicated that both groups improved significantly in functional ability and in decreasing pain levels. Thoracolumbar mobility did not improve significantly in either group. Overall there was no significant difference found between the two types of treatment, although results should be viewed as encouraging for the advocates of both hydrotherapy and land-based exercise as a treatment for chronic LBP.

Relevance of oral intake and necessity to void as ambulatory surgical discharge criteria

Discharge criteria used in the outpatient setting of a 500-bed academic medical center were evaluated by nursing staff in two ambulatory units to determine validity in identifying patient readiness for discharge. Criteria categories include temperature, circulation, activity and mental status, pain, bleeding, voiding, and oral intake. The hospital course and post-discharge course of a convenience sample of 248 ambulatory subjects was drawn from consecutive patients. Post-discharge recovery outcomes identified by the telephone assessment included recovery, complications, necessity of further medical treatment, and the need to return to a medical facility. The descriptive results showed the safety of the seven discharge criteria. Voiding and oral intake were related to prolonged stays in the ambulatory units. Approval was granted by the Hospital Policy Board to relax discharge criteria, and make voiding and oral intake optional for patients. A stage II follow-up study of 1,582 patient subjects was conducted using the new criteria of voluntary voiding and oral intake. The average ambulatory stay was reduced 50 minutes after voiding and oral intake were made optional.

Race, combat, and PTSD in a community sample of New Zealand Vietnam War veterans

The association between posttraumatic stress disorder (PTSD), combat exposure, and race was examined in a New Zealand community sample of 756 Vietnam War veterans. Maori veterans reported higher levels of PTSD than their non-Maori counterparts. However, the race effect was shown to be mediated by combat exposure level, rank, and combat role. These findings support differential experience explanations for the relationship between postwar adjustment and race, suggesting that higher levels of psychological symptoms reported by minority group veterans can be accounted for by their experience of higher levels of combat stressors.

Prevalence of posttraumatic stress disorder, depression and anxiety in a community sample of New Zealand Vietnam War veterans

OBJECTIVE

The aim of the paper is to investigate the prevalence of posttraumatic stress disorder (PTSD), depression and anxiety in a community sample of New Zealand Vietnam War veterans.

METHOD

Data were collected as part of a national survey on the health and mental health of New Zealand Vietnam veterans. Five hundred and seventy-three randomly selected male Vietnam veterans participated in a postal survey. The questionnaire contained a number of demographic, biographical and psychological measures.

RESULTS

The results revealed that 10% of the veterans could be classified as PTSD cases and that these veterans exhibited high levels of depression and anxiety. In PTSD cases, 15% were also classified with anxiety, 6% with depression, and 73% were classified with both anxiety and depression. In PTSD cases 94% were classified with more than one additional disorder. In non-PTSD cases 27% were classified with anxiety, and 1% with depression, while 12% experienced both anxiety and depression.

CONCLUSIONS

The consequences of comorbidity for research and treatment are discussed and it is suggested that health professionals should be attentive to military experience as a predictor of these disorders.

Relation of military service variables to posttraumatic stress disorder in New Zealand Vietnam War veterans

In a community sample of 573 New Zealand Vietnam War veterans, 20% were identified as posttraumatic stress disorder (PTSD) cases. The association between PTSD diagnoses and a range of military experience variables and current demographic variables was examined. Significant differences were reported between cases and non-cases in terms of combat exposure, combat duties, length of service in Vietnam, length of service after Vietnam, total military service, and rank. PTSD cases also differed significantly from non-cases in terms of their age, marital status, income, educational qualifications, and employment status. These results confirm findings from previous studies showing that military experience in Vietnam is significantly associated with current levels of PTSD. They also suggest that veterans with PTSD have poorer social adjustment as indexed by factors such as their current marital and employment status.

Mental and physical health status in a community sample of New Zealand Vietnam War veterans

The data presented in this paper were obtained by a survey involving 573 New Zealand Vietnam veterans. It represents the first comprehensive report on the mental and physical health of a community sample of these ex-service personnel. Although most of these veterans were reasonably healthy for their age, a small proportion was substantially worse off than their Vietnam veteran peers, reporting relatively low levels of psychological wellbeing, relatively high levels of psychological distress and post-traumatic stress disorder, a greater number and severity of physical health symptoms, lower self-rated health status, and making more frequent contacts with health care providers.

Effect of the Gulf War on reactivation of adverse combat-related memories in Vietnam veterans

Symptoms of combat related posttraumatic stress disorder (PTSD) have been reported extensively in Vietnam veterans. A few of these studies have reported situations in which PTSD has been reactivated in veterans with a history of PTSD. The present study reports the effects of media coverage of the Gulf War on a community sample of New Zealand Vietnam veterans. Levels of PTSD, distress, and well-being were assessed before and after the outbreak of hostilities. Most veterans closely followed the media presentation of the war and reported revived memories of Vietnam. Increased memories of Vietnam were associated with higher levels of PTSD and distress. It is suggested that veterans have heightened susceptibility to combat related stimuli because of their previous combat experience and that these stimuli can reactivate PTSD symptoms and distress. Implications of this finding for other groups in the community who harbour residual PTSD effects are discussed.

Bibliotherapy as an adjunct to stimulant medication in the treatment of attention-deficit hyperactivity disorder

The effectiveness of bibliotherapy as an adjunct to stimulant medication in the treatment of children with attention-deficit hyperactivity disorder was investigated. Subjects were randomly assigned to the experimental group, or the control group. Parents in the experimental group received a written protocol (bibliotherapy) outlining behavioral techniques for managing oppositional child behavior. Results indicated significant differences favoring the experimental group on standardized measures of the intensity of behavior problems in the home, parental knowledge of behavioral principles, and teacher ratings of behavior. This bibliotherapy approach appears to offer an inexpensive adjunct to stimulant medication in the treatment of attention-deficit hyperactivity disorder when individual or group behavior management training is not feasible.

Labeling relaxation procedures: impact on adolescent's self-report of effectiveness

Adolescents are being taught relaxation techniques by health-care professionals with increased frequency. The present study examined the effect, on self-reported relaxation, of labeling passive relaxation techniques as "hypnotic relaxation" or as "relaxation training." Subjects were 64 adolescent college students who scored above the 50th percentile, from a subject pool of 189 potential subjects, on the Spielberger Trait Anxiety Inventory. A two by two by two factorial design was utilized with sex, label (hypnotic relaxation versus relaxation training) and relaxation technique (hypnotic induction versus autogenic training) as the independent variables. Under the guise of an investigation of the physiologic correlates of relaxation, subjects were assigned at random to one of four groups. Manipulations of label and relaxation technique were presented on tape via an intercom system. The dependent variable, perceived degree of relaxation, was obtained using a form presented as a "double check" of the accuracy of the physiologic monitoring equipment to which subjects seemingly were attached. Results indicate that the label attached to relaxation techniques can have a significant effect on an individual's subjective report of relaxation depending on the subject's sex.