Studying the genetic basis of drought tolerance in sorghum by managed stress trials and adjustments for phenological and plant height differences.

Managed environments in the form of well watered and water stressed trials were performed to study the genetic basis of grain yield and stay green in sorghum with the objective of validating previously detected QTL. As variations in phenology and plant height may influence QTL detection for the target traits, QTL for flowering time and plant height were introduced as cofactors in QTL analyses for yield and stay green. All but one of the flowering time QTL were detected near yield and stay green QTL. Similar co-localization was observed for two plant height QTL. QTL analysis for yield, using flowering time/plant height cofactors, led to yield QTL on chromosomes 2, 3, 6, 8 and 10. For stay green, QTL on chromosomes 3, 4, 8 and 10 were not related to differences in flowering time/plant height. The physical positions for markers in QTL regions projected on the sorghum genome suggest that the previously detected plant height QTL, Sb-HT9-1, and Dw2, in addition to the maturity gene, Ma5, had a major confounding impact on the expression of yield and stay green QTL. Co-localization between an apparently novel stay green QTL and a yield QTL on chromosome 3 suggests there is potential for indirect selection based on stay green to improve drought tolerance in sorghum. Our QTL study was carried out with a moderately sized population and spanned a limited geographic range, but still the results strongly emphasize the necessity of corrections for phenology in QTL mapping for drought tolerance traits in sorghum.

14 years of experience with the artificial urinary sphincter in children and adolescents without spina bifida.

PURPOSE: The efficacy of the artificial urinary sphincter to treat sphincteric incontinence in pediatric patients with spina bifida has been clearly reported. The possibility of maintaining spontaneous voiding has usually been the main reason for prosthetic device surgery. We reviewed our experience with the artificial urinary sphincter in patients without spina bifida who had had previous surgery of the bladder neck or proximal urethra. MATERIALS AND METHODS: From 1990 to 2004, 112 children and adolescents underwent implantation of an AMS 800 artificial urinary sphincter. Of the patients 19 males and 4 females (20.5%) between ages 4 and 17 years (mean 8.1) had no spina bifida. Instead there were bladder exstrophy in 12 patients, anorectal malformation with a rectourethral or vesical fistula in 7 and epispadias in 4. A bladder neck cuff between 5.5 and 7.5 cm, and a 61-70 balloon were used in all patients. RESULTS: Only 1 patient was lost to followup. In 22 patients (95.6%) mean followup was 80 months (range 4 to 155). Three sphincters in patients with exstrophy were removed because of erosion and/or infection 5, 49 and 60 months after initial surgery, respectively. A total of 19 sphincters remained in place (86.3% survival rate) with 5 revisions (26.3%) because of the pump (2), the cuff (2) or balloon fluid leakage. In this group 13 patients (68.4%) voided spontaneously and 6 (31.6%) performed clean intermittent catheterization, although 3 also voided spontaneously. Overall continence was good in 87% of patients because 2 were still incontinent at night. CONCLUSIONS: The artificial urinary sphincter is a good long-term solution to urinary incontinence secondary to sphincter incompetence despite multiple previous surgeries of the bladder neck or proximal urethra. Patients with bladder exstrophy and many previous bladder procedures are more exposed to complications such as erosion compared with patients with epispadias or anorectal malformation. The high percent of patients maintaining spontaneous voiding and the good rate of continence are the most important benefits of this type of surgical option for sphincter incompetence.

Patterns of DNA damage and photoinhibition in temperate South-Atlantic picophytoplankton exposed to solar ultraviolet radiation.

Natural marine phytoplankton assemblages from Bahía Bustamante (Chubut, Argentina, 45 degrees S, 66.5 degrees W), mainly consisting of cells in the picoplankton size range (0.2-2 microm), were exposed to various UVBR (280-315 nm) and UVAR (315-400 nm) regimes in order to follow wavelength-dependent patterns of cyclobutane pyrimidine dimer (CPD) induction and repair. Simultaneously, UVR induced photosynthetic inhibition was studied in radiocarbon incorporation experiments. Biological weighting functions (BWFs) for photoinhibition and for CPD induction, the latter measured in bare calf thymus DNA, differed in the UVAR region: carbon incorporation was reduced markedly due to UVAR, whereas no measurable UVAR effect was found on CPD formation. In contrast, BWFs for inhibition of photosynthesis and CPD accumulation were fairly similar in the UVBR region, especially above 300 nm. Incubation of phytoplankton under full solar radiation caused rapid CPD accumulation over the day, giving maximum damage levels exceeding 500 CPD MB(-1) at the end of the afternoon. A clear daily pattern of CPD accumulation was found, in keeping with the DNA effective dose measured by a DNA dosimeter. In contrast, UVBR induced photosynthetic inhibition was not dose related and remained nearly constant during the day. Screening of UVBR or UVR did not cause significant CPD removal, indicating that photoreactivation either by PAR or UVAR was of minor importance in these organisms. High CPD levels were found in situ early in the morning, which remained unaffected notwithstanding treatments favoring photorepair. These results imply that a proportion of cells had been killed by UVBR exposure prior to the treatments. Our data suggest that the limited potential for photoreactivation in picophytoplankton assemblages from the southern Atlantic Ocean causes high CPD accumulation as a result of UVBR exposure.

Shedding of soluble receptor for tumor necrosis factor alpha induced by M. leprae or LPS from human mononuclear cells.

Cell surface expression and release of the tumor necrosis factor receptor (TNFR type I) was analyzed after stimulation of peripheral blood mononuclear cells (PBMC) with Mycobacterium leprae (M. leprae) or lipopolysaccharide (LPS). A transient spontaneous expression of TNFR type I on the surface of PBMC was observed. Two hr after activation with LPS, a significant reduction of TNFR type I expression was detected: Release of TNFR type I by M. leprae or LPS-stimulated PBMC was evaluated with an enzyme-linked immunoabsorbent assay. This release occurred relatively later (20 to 40 hr) than the secretion of TNF alpha which reached high levels between 8 to 20 hr after activation. Thalidomide, a potent drug for the treatment of erythema nodosum leprosum episodes by inhibiting TNF alpha production, had no influence on the TNFR type I expression. Similar results were obtained with pentoxifylline. It is concluded that the release of TNFR type I by M. leprae or LPS-stimulated PBMC may counteract the pro-inflammatory activities of TNF alpha, by reducing the systemic toxicity of this cytokine in leprosy.