Validation of Genotyping by Sequencing Using Transcriptomics for Diversity and Application of Genomic Selection in Tetraploid Potato.

Potato is an important food crop due to its increasing consumption, and as a result, there is demand for varieties with improved production. However, the current status of breeding for improved varieties is a long process which relies heavily on phenotypic evaluation and dated molecular techniques and has little emphasis on modern genotyping approaches. Evaluation and selection before a cultivar is commercialized typically takes 10-15 years. Molecular markers have been developed for disease and pest resistance, resulting in initial marker-assisted selection in breeding. This study has evaluated and implemented a high-throughput transcriptome sequencing method for dense marker discovery in potato for the application of genomic selection. An Australian relevant collection of commercial cultivars was selected, and identification and distribution of high quality SNPs were examined using standard bioinformatic pipelines and a custom approach for the prediction of allelic dosage. As a result, a large number of SNP markers were identified and filtered to generate a high-quality subset that was then combined with historic phenotypic data to assess the approach for genomic selection. Genomic selection potential was predicted for highly heritable traits and the approach demonstrated advantages over the previously used technologies in terms of markers identified as well as costs incurred. The high-quality SNP list also provided acceptable genome coverage which demonstrates its applicability for much larger future studies. This SNP list was also annotated to provide an indication of function and will serve as a resource for the community in future studies. Genome wide marker tools will provide significant benefits for potato breeding efforts and the application of genomic selection will greatly enhance genetic progress.

How reliable is axillary temperature measurement?

AIM: To assess whether axillary temperature measurements reliably reflect oral/rectal temperature measurements. METHODS: This observational study compared paired axillary-rectal and axillary-oral temperatures in a general paediatric ward with the participation of 225 children aged < or = 4 y and 112 children aged between 4 and 14 y. RESULTS: Changes in oral/rectal and axillary temperatures correlated significantly (p < 0.0001). However, axillary temperature measurements were significantly lower than both oral (mean -0.56 degrees C, SD 0.76 degrees C) and rectal measurements (0.38 degrees C; SD 0.76 degrees C). Ninety-five percent of axillary measurements fell within a 2.5-3 degrees C range around respective paired oral/rectal measurements. The mean difference increased with increasing temperature, and was 0.4 degrees C at low body temperatures, and over 1 degree C with a fever of 39 degrees C. Neither seasonal fluctuations nor the amount of clothing worn influenced this difference. CONCLUSION: Axillary temperatures in young children do not reliably reflect oral/rectal temperatures and should therefore be interpreted with caution.

Evacuation proctography in normal volunteers.

Constipated patients evaluated by evacuation proctography may be subjected to vigorous medical therapy or surgery, even colectomy, based on radiographic findings that have been called "abnormal" in the literature. Criteria for normal defecography are not uniformly established, nor has correlation of structural or functional findings with symptoms been clearly documented. We prospectively studied 21 asymptomatic volunteers to assess the frequency of findings in a control population, and to establish a quantitative measure of normal rectal emptying. Standard defecography technique demonstrated rectocele, intussusception, pelvic descent, or puborectalis spasm in 14/21 volunteers (67%). The range of rectal emptying was 12.5% to 100%, with four subjects (19%) evacuating less than or equal to 40% of the barium paste. There was no correlation between severity of radiographic findings and degree of evacuation. Defecography results in patients being considered for symptomatic intervention should be interpreted cautiously, given the wide range of normal variation in a control population.

Anorectal sensory and motor function in neurogenic fecal incontinence. Comparison between multiple sclerosis and diabetes mellitus.

We measured anorectal sensory and motor function in 11 patients with multiple sclerosis and fecal incontinence, 11 continent patients with multiple sclerosis, 10 diabetics with fecal incontinence, and 12 healthy control subjects. The threshold volume at which patients with multiple sclerosis and fecal incontinence experienced rectal sensation was higher than that in healthy controls (42.7 +/- 6.2 mL vs. 13.3 +/- 2.8 mL; P less than 0.01) and was similar to that in incontinent diabetics (36.5 +/- 5.7 mL). Patients with multiple sclerosis and incontinent diabetics also showed increased thresholds of phasic external sphincter contraction compared with controls (P less than 0.05). Diabetics with incontinence had reduced resting and maximal voluntary anal sphincter pressures compared with controls (P less than 0.05), whereas patients with multiple sclerosis and incontinence showed only decreased maximal voluntary anal sphincter pressures (P less than 0.01 vs. controls and diabetics). Incontinent patients with multiple sclerosis also required smaller volumes of rectal distention to inhibit internal sphincter tone compared with diabetics and controls (P less than 0.01). Decreased maximal voluntary squeeze pressures were less severe in continent patients with multiple sclerosis than in incontinent patients with multiple sclerosis. We conclude that impaired function of the external anal sphincter and decreased volumes of rectal distention to inhibit the internal anal sphincter or both may contribute to fecal incontinence in multiple sclerosis. In addition, increased thresholds of conscious rectal sensation in some incontinent patients with multiple sclerosis and diabetes mellitus may contribute to fecal incontinence by impairing the recognition of impending defecation.

Contributions of evacuation proctography and anorectal manometry to evaluation of adults with constipation and defecatory difficulty.

We prospectively evaluated 36 patients who complained of chronic constipation and/or defecatory difficulties to determine the role of anorectal manometry and evacuation proctography in delineating the pathogenesis of these complaints. Twenty patients with constipation also underwent a colonic transit study with radioopaque markers, which identified one group with normal transit (N = 10) and another with slow transit (N = 10). Nine of 36 patients (25%) had inappropriate puborectalis muscle contraction or exhibited weak expulsion efforts during evacuation proctography, and these correlated highly with poor rectal emptying of barium paste (20 +/- 6% vs 61 +/- 5% in patients with normal relaxation; P less than 0.01). However, poor rectal emptying did not correlate with the presence of high-grade intussusceptions, large rectoceles, anorectal angles at rest or with straining, rectal diameter, clinical features, or colonic transit. Moreover, abnormal expulsion patterns as seen with anorectal manometry correlated poorly with the presence of inappropriate puborectalis contraction and decreased rectal emptying by proctography. Although anatomic abnormalities occurred frequently in patients with constipation and/or defecatory difficulties, they were also prevalent in asymptomatic controls. In view of these findings, surgical intervention to correct anatomic abnormalities in patients with constipation and/or defecatory difficulties should be considered only with great caution.

Psychological and physiological characteristics of patients with severe idiopathic constipation.

This study prospectively evaluated psychological profiles and selected parameters of colonic and anorectal sensorimotor function in 25 consecutive patients who were referred for severe idiopathic constipation. Measurement of colonic transit of radiopaque markers divided patients into those with normal transit (n = 10) and those with slow transit (n = 15). As measured by the Hopkins Symptom Checklist, patients with normal transit constipation demonstrated significantly higher scores for psychological distress in the global symptoms index and nine clinical subscales than did those with slow transit constipation and gastrointestinal control subjects (n = 25). Both groups with constipation had decreased rectal sensation compared with controls but there was no relationship to rectal compliance or threshold of internal sphincter relaxation. There was also no relation between abnormalities of anorectal parameters, including expulsion dynamics, and psychological profiles in two groups. Measurement of colonic transit and psychological profiles in patients with severe idiopathic constipation identify two groups of patients with respect to possible pathogenesis of symptoms. Accordingly, different therapeutic approaches may be required, one behaviourally and psychologically based and the other focused on the possible modification of disordered colonic transit.