Alternating verbal fluency performance following bilateral subthalamic nucleus deep brain stimulation for Parkinson's disease.

BACKGROUND AND PURPOSE: Despite common occurrences of verbal fluency declines following bilateral subthalamic nucleus deep brain stimulation (STN-DBS) for the treatment of Parkinson's disease (PD), alternating fluency measures using cued and uncued paradigms have not been evaluated. METHODS: Twenty-three STN-DBS patients were compared with 20 non-surgical PD patients on a comprehensive neuropsychological assessment, including cued and uncued intradimensional (phonemic/phonemic and semantic/semantic) and extradimensional (phonemic/semantic) alternating fluency measures at baseline and 6-month follow-up. RESULTS: STN-DBS patients demonstrated a greater decline on the cued phonemic/phonemic fluency and the uncued phonemic/semantic fluency tasks compared to the PD patients. For STN-DBS patients, verbal learning and information processing speed accounted for a significant proportion of the variance in declines in alternating phonemic/phonemic and phonemic/semantic fluency scores, respectively, whilst only naming was related to uncued phonemic/semantic performance for the PD patients. Both groups were aided by cueing for the extradimensional task at baseline and follow-up, and the PD patients were also aided by cueing for the phonemic/phonemic task on follow-up. CONCLUSIONS: These findings suggest that changes in alternating fluency are not related to disease progression alone as STN-DBS patients demonstrated greater declines over time than the PD patients, and this change was related to declines in information processing speed.

Minilaparotomy cholecystectomy in children.

AIM: Scarcity of paediatric cholelithiasis limits the obtainable experience in paediatric laparoscopic cholecystectomy (LPC). We report minilaparotomy cholecystectomy (MLC) in children which may be a useful alternative to LPC avoiding the added cost of disposable laparoscopic equipment. METHODS: Nineteen cases underwent a retrograde MLC using a 2-4 cm transverse right upper quadrant incision. Various parameters were assessed. RESULTS: Mean age at presentation was 10.87 years, mean length of the incision 2.8 cm, mean operative time 36.5 min, mean analgesic requirement 2 days, mean time to feed/ mobilize 1 day each, and mean duration of hospital stay was 2.7 days. All had satisfactory cosmetic result without postoperative complications. CONCLUSIONS: MLC in children involves a small incision, excellent cosmetic scar and rapid postoperative recovery at relatively low cost. It is a good alternative to LPC.

Does the absence of anal reflexes guarantee a "safe bladder" in children with spina bifida?

INTRODUCTION: Increased detrusor pressure is a risk factor for renal damage in patients with neuropathic bladder, and probably requires inappropriate contraction of the external urethral sphincter. It seems logical that the absence of sacrally-mediated anal reflexes in a child with spina bifida makes such sphincteric spasm unlikely. One report has suggested that, in such circumstances, neuropathic bladder behaviour is usually predictable and safe. This article examines the reliability of this assumption, and whether routine urodynamic studies can be, therefore, safely omitted in this group. MATERIALS AND METHODS: 76 children and adolescents (aged 3 - 18 years) with spina bifida were tested for the presence of the anocutaneous reflex immediately prior to video-urodynamic studies, on entry into a therapeutic trial. The relationship between the anal reflex status and two surrogate indicators of urethral sphincter function, namely maximal detrusor pressure (MDP) and leak point pressure (LPP), was analysed. RESULTS: Only 11 (14 %) children had a positive reflex. Their mean MDP and their mean LPP were not statistically significantly greater than those in children without an intact reflex. Indeed the reflex was absent in the only two patients with MDP, > or = 100 cm H2O, and in the only five children with LPP, > or = 60 cm H2O. CONCLUSION: The absence of anal reflexes is a poor predictor of safe bladder pressures in children with spina bifida. There is no justification for depriving such a population of routine urodynamic assessment on this basis. Our impression remains that there is probably no such entity as a predictably safe neuropathic bladder.

Does bladder capacity assessment by frequency/volume chart correlate well with urodynamic estimation in children with spina bifida?

INTRODUCTION: Reduced capacity is a common feature of the neuropathic bladder seen in children with spina bifida. This impacts on urinary continence and, in severe cases, may require augmentation cystoplasty. The traditional means of assessing bladder size has been urodynamics. A frequency/volume chart may also provide this information, but the technique may not be so scientifically controlled. It is unclear how well the results of these two modalities correlate. MATERIALS AND METHODS: One hundred and twenty-two urodynamic studies and one-week frequency/volume charts were completed by 77 children and adolescents (aged 3 - 18 years) involved in a therapeutic trial. The maximum bladder capacity at urodynamics and the largest of the listed voided urinary volumes over the week for each child were compared using the paired, samples t-test. A scatter plot correlation analysis was performed, along with a Bland-Altman test for method comparison. RESULTS: A mean difference in bladder capacity estimation, between the two methods of between 12 and 18 ml was encountered, which was statistically non-significant. While a generally good correlation was seen, there was poor agreement between the two modalities. CONCLUSION: Frequency/volume charts provide a reliable non-invasive estimate of bladder size in children with neuropathic bladder. However, the potential for poor agreement with urodynamic measurements means the two techniques should be seen as supplementary, rather than interchangeable, in this group.

Analysis of Arabidopsis genome sequence reveals a large new gene family in plants.

A detailed analysis of the currently available Arabidopsis thaliana genomic sequence has revealed the presence of a large number of open reading frames with homology to the stigmatic self-incompatibility (S) genes of Papaver rhoeas. The products of these potential genes are all predicted to be relatively small, basic, secreted proteins with similar predicted secondary structures. We have named these potential genes SPH (S-protein homologues). Their presence appears to have been largely missed by the prediction methods currently used on the genomic sequence. Equivalent homologues could not be detected in the human, microbial, Drosophila or C. elegans genomic databases, suggesting a function specific to plants. Preliminary RT-PCR analysis indicates that at least two members of the family (SPH1, SPH8) are expressed, with expression being greatest in floral tissues. The gene family may total more than 100 members, and its discovery not only illustrates the importance of the genome sequencing efforts, but also indicates the extent of information which remains hidden after the initial trawl for potential genes.

The association of flowering time quantitative trait loci with duplicated regions and candidate loci in Brassica oleracea.

A population of 150 doubled haploid lines of rapid cycling Brassica oleracea, derived from an F1 from a var. alboglabra x var. italica cross, was scored for flowering time in two trials. Using information on 82 mapped molecular markers, spread evenly across the nine linkage groups, QTL were identified at six locations; one each on linkage groups O2 and O3 and two each on linkage groups O5 and O9. In total, these QTL explained 58 and 93% of the genetical variation in the two trials. Three of these QTL, on linkage groups O2, O3, and O9, were situated in regions showing considerable homology both with each other and with chromosome regions of B. nigra that have been shown to affect flowering time. These same regions are all homologous to a single tract of Arabidopsis chromosome 5, which contains a number of the flowering-related genes, one or more of which may be candidates for the QTL found in Brassica.

Construction of a RFLP genetic linkage map for oil palm (Elaeis guineensis Jacq.).

We have developed a restriction fragment length polymorphism (RFLP) genetic map in oil palm (Elaeis guineensis Jacq.) for use in breeding programmes. A segregating population of 98 individuals was probed with 84 informative low copy clones (mainly PstI genomics). This yielded 103 scorable loci, of which 97 could be linked into 24 groups of two or more markers (n = 16 for oil palm), encompassing a total of 860 cM. The high level of linkage between markers (95%) suggests good genome coverage and very little segregation distortion of markers was observed. The mapping population, which was generated by the selfing of an important breeding palm (A 137/30), also segregated for the shell thickness character (Sh), enabling mapping of the gene conferring this major commercial trait. The nearest RFLP marker (pOPgSP1282) was located 9.8 cM from Sh in the mapping population and 6.6 cM away in a related (A137/30 x E80/29) smaller population (45 palms). Strategies for conversion of RFLP markers to a PCR format were explored and two important markers were shown to generate allelic variants following PCR amplification and restriction digestion of PCR products. The application of this map to oil palm breeding programmes is discussed.

Altered bladder and bowel function following cutaneous electrical field stimulation in children with spina bifida--interim results of a randomized double-blind placebo-controlled trial.

Bladder and bowel dysfunction in spina bifida are the result of abnormal electrical input, secondary to the neurological lesion of the spinal cord. Experimental attempts to correct this deficit with invasive electrical stimulation have demonstrated promising effects, as has a recent preliminary study of transcutaneous electro-stimulation in children with myelomeningocoele. A randomized controlled trial of non-invasive electrical stimulation in children with neuropathic bladder and bowel has been established. Interim results of 50 patients are presented. Treatment was performed at home for one hour daily for a mean period of 45 days. The only statistically significant difference between the active and placebo-groups was a 32% relative decrease in night-time urinary incontinence, favoring the placebo group. However there were non-significant trends of preferential improvement in the active group for the relative increases in maximum and average bladder content and episodes of spontaneous normal defecation. It is anticipated that a continued increase in patient numbers will overcome the large placebo effect observed and yield more significant results.

The construction of a substitution library of recombinant backcross lines in Brassica oleracea for the precision mapping of quantitative trait loci.

The currently available methods for locating quantitative trait loci (QTLs) and measuring their effects in segregating populations lack precision unless individual QTLs have very high heritabilities. The use of recombinant backcross lines containing short regions of donor chromosome introgressed into a constant recipient background permits QTLs to be located with greater precision. The present paper describes the use of molecular markers to introgress defined short regions of chromosome from a donor doubled haploid calabrese line of Brassica oleracea (var. italica) into a recipient short generation variety (Brassica oleracea var. alboglabra). We demonstrate that in just two or three generations of backcrossing, combined with selection for mapped molecular markers, the generation of a library of recombinant backcross lines is feasible. The possible use and refinement of these lines are discussed. Key words : backcrossing, Brassica oleracea, introgression, molecular markers, near-isogenic lines, QTL mapping, recombinant backcross lines, substitution lines.

Towards developing intervarietal substitution lines in Brassica napus using marker-assisted selection.

Sets of substitution lines have advantages over segregating populations for the rigorous analysis of loci influencing quantitative traits. A general strategy for the rapid production of substitution lines was developed. It involved the systematic application of marker-assisted selection over 2-4 generations of backcrossing. The effectiveness of this strategy was demonstrated by the production of intervarietal substitution lines in Brassica napus. A genetic map containing 158 loci, distributed across all 19 B. napus linkage groups and assayed in 200 B1 individuals, was generated. Six complementary B1 individuals enriched for recurrent genotype and collectively carrying almost all the donor genome were selected. A total of 288 B2 plants derived from the selected B1 individuals were analysed and complementary individuals carrying five or fewer donor segments were identified. Similar selection, carried out on 250 B3 plants from two distinct B1 lineages, identified 74 B3 individuals carrying one or two donor segments. Together, 12 of these isolated segments represented 33% of the mapped genome. Lines homozygous for single substituted segments were derived from selfed progeny of selected B3 plants. A full set of substitution lines will be used to elucidate the genetic control of quantitative production traits in oilseed rape over several environments. Key words : QTL mapping, quantitative genetics, backcross, genetic linkage map, plant breeding, restriction fragment length polymorphism.

Higher recombination frequencies in female compared to male meisoses in Brassica oleracea.

Linkage maps of the nine chromosomes of Brassica oleracea, based on 75 informative molecular markers, have been compared in first and second backcross progeny from a cross between two doubled haploid lines. The second backcross progeny showed greater recombination frequencies for 75% of the pairs of adjacent markers, but there was no obvious indication that this effect was localised to particular regions of the chromosomes. Four chromosomes increased in genetic length more than twofold, while overall, the total map was 66% longer. The possible causes of this discrepancy are analysed. A sex difference in chiasma distribution and/or frequency at meiosis is thought to be the most likely explanation. The implications of this finding for mapping and map-based applications are discussed.