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Biomedical subjects

M Oliver

Publications and source records attributed to M Oliver.

At least 19 recordsLinked to original sources
PubMed2006

Construction of a watermelon BAC library and identification of SSRs anchored to melon or Arabidopsis genomes.

A bacterial artificial chromosome (BAC) library was constructed for watermelon (Citrullus lanatus (Thunb.) Matsum. & Nakai var. lanatus) with an average insert-size of 106 kb, providing 21 haploid genome equivalents. The library was used to identify BAC clones that are anchored to probes evenly distributed on the genomes of melon or Arabidopsis. Twenty eight probes (representing 66% of the tested probes) from melon and 30 probes (65%) from Arabidopsis identified positive BAC clones. Two methods were implemented to identify SSRs from the positively hybridizing BAC clones. First, analysis of BAC end sequences revealed 37 SSRs. For the second method, pooled DNA of BACs identified by the melon probes was used to develop a shotgun library. The library was then screened with synthetic SSR oligonucleotides by hybridization. Sequence analysis of positively hybridizing shotgun clones revealed 142 different SSRs. Thirty eight SSRs were characterized using three watermelon cultivars, five plant introduction (PI) accessions of C. lanatus var lanatus and four PIs of C. lanatus var citroides. Of these, 36 (95%) were found to be polymorphic with up to six alleles per marker. Polymorphism information content values for polymorphic markers varied between 0.22 and 0.79 with an average of 0.53. The methods described herein will be valuable for the construction of a watermelon linkage map with SSRs evenly distributed on its genome that is anchored to the genomes of melon and Arabidopsis.

Alleles↗
PubMed2006

Evaluation of novel fluorogenic substrates for the detection of glycosidases in Escherichia coli and enterococci.

AIMS: Enzyme substrates based on 4-methylumbelliferone are widely used for the detection of Escherichia coli and enterococci in water, by detection of beta-glucuronidase and beta-glucosidase activity respectively. This study aimed to synthesize and evaluate novel umbelliferone-based substrates with improved sensitivity for these two enzymes. METHODS AND RESULTS: A novel beta-glucuronide derivative based on 6-chloro-4-methylumbelliferone (CMUG) was synthesized and compared with 4-methylumbelliferyl-beta-D-glucuronide (MUG) using 42 strains of E. coli in a modified membrane lauryl sulfate broth. Over 7 h of incubation, the fluorescence generated from the hydrolysis of CMUG by E. coli was over twice that from MUG, and all of the 38 glucuronidase-positive strains generated a higher fluorescence with CMUG compared with MUG. Neither substrate caused inhibition of bacterial growth in any of the tested strains. Four beta-glucosidase substrates were also synthesized and evaluated in comparison with 4-methylumbelliferyl-beta-D-glucoside (MU-GLU) using 42 strains of enterococci in glucose azide broth. The four substrates comprised beta-glucoside derivatives of umbelliferone-3-carboxylic acid and its methyl, ethyl and benzyl esters. Glucosides of the methyl, ethyl and benzyl esters of umbelliferone-3-carboxylic acid, were found to be superior to MU-GLU for the detection of enterococci, especially after 18 h of incubation, while umbelliferone-3-carboxylic acid-beta-D-glucoside was inferior. However, the variability in detectable beta-glucosidase activity among the different strains of enterococci in short-term assays using the three carboxylate esters (7 h incubation) may compromise their use for rapid detection and enumeration of these faecal indicator bacteria. CONCLUSIONS: The beta-glucuronidase substrate CMUG appears to be a more promising detection system than the various beta-glucosidase substrates tested. SIGNIFICANCE AND IMPACT OF THE STUDY: The novel substrate CMUG showed enhanced sensitivity for the detection of beta-glucuronidase-producing bacteria such as E. coli, with a clear potential for application in rapid assays for the detection of this indicator organism in natural water and other environmental samples.

Cellulases↗
PubMed2006

Evaluation of a new chromogenic agar medium for isolation and identification of Group B streptococci.

AIMS: To evaluate a new chromogenic agar as a screening medium for the isolation of Group B streptococci from high vaginal swabs from pregnant women. METHODS AND RESULTS: The medium was evaluated with 195 high vaginal swabs referred for antenatal screening and compared with blood agar and Granada medium. The new chromogenic medium showed 100% sensitivity for the detection of Group B streptococci, and also showed a positive predictive value of 100%. Granada medium also showed excellent sensitivity and specificity and both media were superior to blood agar. CONCLUSIONS: The new chromogenic medium showed excellent performance for the detection of Group B streptococci from clinical samples. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first chromogenic medium described for the detection of Group B streptococci. The medium offers an effective and convenient alternative to conventional media, currently used in clinical laboratories.

Agar↗
PubMed2005

Simple-sequence repeat markers used in merging linkage maps of melon (Cucumis melo L.).

A set of 118 simple sequence repeat (SSR) markers has been developed in melon from two different sources: genomic libraries (gSSR) and expressed sequence-tag (EST) databases (EST-SSR). Forty-nine percent of the markers showed polymorphism between the 'Piel de Sapo' (PS) and PI161375 melon genotypes used as parents for the mapping populations. Similar polymorphism levels were found in gSSR (51.2%) and EST-SSR (45.5%). Two populations, F2 and a set of double haploid lines (DHLs), developed from the same parent genotypes were used for map construction. Twenty-three SSRs and 79 restriction fragment length polymorphisms (RFLPs), evenly distributed through the melon genome, were used to anchor the maps of both populations. Ten cucumber SSRs, 41 gSSRs, 16 EST-SSR, three single nucleotide polymorphism (SNP) markers, and the Nsv locus were added in the DHL population. The maps developed in the F2 and DHL populations were co-linear, with similar lengths, except in linkage groups G1, G9, and G10. There was segregation distortion in a higher proportion of markers in the DHL population compared with the F2, probably caused by selection during the construction of DHLs through in vitro culture. After map merging, a composite genetic map was obtained including 327 transferable markers: 226 RFLPs, 97 SSRs, three SNPs, and the Nsv locus. The map length is 1,021 cM, distributed in 12 linkage groups, and map density is 3.11 cM/marker. SSR markers alone cover nearly 80% of the map length. This map is proposed as a basis for a framework melon map to be merged with other maps and as an anchor point for map comparison between species of the Cucurbitaceae family.

Chromosome Mapping↗
PubMed2005

Objectively-measured physical activity in New Zealand workers.

To date, no objective measurements of New Zealanders' physical activity have been reported. The relative contribution of work time activity to total daily physical activity by gender and occupational category has also not been measured objectively in any population. The present study reports such data using pedometer steps counts to quantify both work and non-work physical activity in a sample of New Zealand adult workers in six different occupational categories over a three-day period. Females (9943+/-3855 steps) had slightly higher, but not significantly different (F=0.084(1,179)1, p=0.772) daily step counts than males (9766+/-3965 steps). Using the 10 000 steps a day criterion, 57% of the sample were considered at least low-active. Analysis of variance was used to identify between group (occupational) differences in workplace physical activity (F=11.189(5,175), p<0.001), non-work physical activity (F=2.596(5.175), p=0.027), and total physical activity (F=6.265(5,175), p<0.001). Tukey post hoc comparisons showed significant differences with retail and blue collar workers achieving higher activity levels in comparison to the other occupational categories in work and total physical activity. Odds ratios were calculated to find the odds of being in the top half of activity classification for work and non-work physical activity by tertile splits of work time, active transportation use, sport and exercise participation, television and computer viewing, and passive recreation. Active transportation and passive recreation were related to increased odds of higher work pedometer steps. For non-work pedometer values, television and computer use increased the likelihood of being in the lowest activity group, while sport and exercise participation were associated with increased activity levels.

Adult↗
PubMed2005

Severe colonic diverticulitis in an adolescent with Williams syndrome.

Williams Syndrome (WS) is a condition with multisystemic involvement caused by a genetic deletion in chromosome 7. Colonic diverticulosis has been described in adults with WS; however, it has not previously been reported in adolescents with WS. We report an adolescent boy with WS who developed complicated colonic diverticulitis and briefly review the possible aetiology of diverticular disease.

Adolescent↗
PubMed2003

Identification of quantitative trait loci involved in fruit quality traits in melon (Cucumis melo L.).

Two populations [an F(2) and a set of 77 double haploid lines (DHLs)] developed from a cross between a 'Piel de Sapo' cultivar (PS) and the exotic Korean accession PI 161375 were used to detect QTLs involved in melon fruit quality traits: earliness (EA), fruit shape (FS), fruit weight (FW) and sugar content (SSC); and loci involved in the colour traits: external colour (ECOL) and flesh colour (FC). High variation was found, showing transgressive segregations for all traits. The highest correlation among experiments was observed for FS and the lowest for FW and SSC. Correlations among traits within experiments were, in general, not significant. QTL analysis, performed by Composite Interval Mapping, allowed the detection of nine QTLs for EA, eight for FS, six for FW and five for SSC. Major QTLs ( R(2)>25%) were detected for all traits. QTLs for different traits were no clearly co-localised, suggesting low pleiotropic effects at QTLs. Sixty-one per cent of them were detected in two or more experiments. QTLs for FS were detected in more trials than QTLs for FW and SSC, confirming that FS is under highly hereditable polygenic control. ECOL segregated as yellow:green in both experimental populations. The genetic control of ECOL was found to be complex, probably involving more than two loci with epistatic interactions. One of these loci was mapped on linkage group 9, but the other loci could not be clearly resolved. FC segregated as white:green:orange. The locus responsible for the green FC was mapped on linkage group 1, and it was proposed to correspond to the previously described locus gf. The genetic control of orange FC was complex: two loci in linkage groups 2 and 12 were associated with orange flesh, but larger population sizes would be necessary to elucidate completely the genetic control of orange flesh in this cross. Exotic alleles from PI161375 showed beneficial effects on EA, FW and SSC, indicating the usefulness of PI 161375 as a new source of genetic variability to improve European and American cultivars.

Chromosome Mapping↗
PubMed2002

Evaluating web-based learning modules during an MSc programme in dental public health: a case study.

The introduction of web-based learning in dentistry has raised important educational questions about the efficacy of different teaching approaches. However, studies to date have drawn conclusions that appear conflicting, or at the least, ambiguous. In this paper, it will be argued that an over-simplistic view of education and an inappropriate use of methodology have both contributed to this confusion. These points will be illustrated through the use of a case study of web-based learning in dental public health.

Computer-Assisted Instruction↗
PubMed2001

Long-term follow-up of occlusion therapy in amblyopia.

OBJECTIVE: To determine whether the results of occlusion therapy for amblyopia are maintained into adulthood. DESIGN: Prospective, observational case series. PARTICIPANTS: Fifty-four patients, who were successfully treated in childhood for unilateral amblyopia by occlusion, were followed up to the age of 9 years, were evaluated in 1984 for long-term results 6.4 years on average after cessation of treatment, and accepted our invitation for reevaluation in 1999. METHODS: All patients were given a complete eye examination. The visual acuity (VA) was measured. RESULTS: The average period of follow-up was 21.5 years (range, 17.2-25.1 years). The mean age at the most recent examination was 29.0 +/- 2.1 years (range, 25.1-34). At this examination, a best-corrected visual acuity (BCVA) of 20/40 or better was achieved by 72.3% of the patients. The mean BCVA was 20/35 (20/25-20/70) at the end of occlusion therapy, 20/45 (20/20-20/300) in 1984, and 20/34 (20/15-20/100) at the present examination. Relative to the results at the end of therapy, BCVA at the present examination was maintained or improved in 66.7% of the patients. Relative to 1984, the BCVA in 1999 was maintained or improved in 87% of the patients. MAIN OUTCOME MEASURE: Visual acuity. CONCLUSION: Comparative evaluation of BCVA at a long-term follow-up examination, performed 21.5 years on average after cessation of occlusion therapy, showed that VA was maintained or improved in two thirds of patients who had been successfully treated by occlusion for unilateral amblyopia in childhood.

Adult↗
PubMed2001

Urinary uranium concentrations in an enlarged Gulf War veteran cohort.

Depleted uranium was first used on a large scale as a major component of munitions and armaments employed by the U.S. armed forces during the Gulf War in 1991. In response to concern that exposure to depleted uranium may have been a cause of health problems suffered by returning veterans of that war, an already existing surveillance program following depleted uranium "friendly fire" victims was enlarged to assess the wider veteran community's exposure to depleted uranium. Between August 1998 and December 1999, 169 Gulf War veterans submitted 24-h urine samples for determination of urinary uranium concentration and questionnaires describing their potential exposures to depleted uranium while in the Gulf War theatre. Depleted uranium exposure assessment was determined from 30 separate questionnaire items condensed into 19 distinct exposure scenarios. Results of urine uranium analysis were stratified into high and low uranium groups with 0.05 microg uranium/g creatinine being the cut point and approximate upper limit of the normal population distribution. Twelve individuals (7.1%) exhibited urine uranium values in the high range, while the remaining 157 had urine uranium values in the low range. A repeat test of urine for 6 of these 12 produced uranium results in the low range for 3 of these individuals. Exposure scenarios of the high and low uranium groups were similar with the presence of retained shrapnel being the only scenario predictive of a high urine uranium value. Results emphasize the unlikely occurrence of an elevated urine uranium result and consequently any uranium-related health effects in the absence of retained depleted uranium metal fragments in the veterans.

Cohort Studies↗
PubMed2001

Surveillance of depleted uranium exposed Gulf War veterans: health effects observed in an enlarged "friendly fire" cohort.

To determine clinical health effects in a small group of US Gulf War veterans (n = 50) who were victims of depleted uranium (DU) "friendly fire," we performed periodic medical surveillance examinations. We obtained urine uranium determinations, clinical laboratory values, reproductive health measures, neurocognitive assessments, and genotoxicity measures. DU-exposed Gulf War veterans with retained metal shrapnel fragments were excreting elevated levels of urine uranium 8 years after their first exposure (range, 0.018 to 39.1 micrograms/g creatinine for DU-exposed Gulf War veterans with retained fragments vs 0.002 to 0.231 microgram/g creatinine in DU exposed but without fragments). The persistence of the elevated urine uranium suggests ongoing mobilization from the DU fragments and results in chronic systemic exposure. Clinical laboratory outcomes, including renal functioning, were essentially normal. Neurocognitive measures showing subtle differences between high and low uranium exposure groups, seen previously, have since diminished. Sister chromatid exchange frequency, a measure of mutation in peripheral lymphocytes, was related to urine uranium level (6.35 sister chromatid exchanges/cell in the high uranium exposure group vs 5.52 sister chromatid exchanges/cell in the low uranium exposure group; P = 0.03). Observed health effects were related to subtle but biologically plausible perturbations in central nervous system function and a general measure of mutagen exposure. The findings related to uranium's chemical rather than radiologic toxicity. Observations in this group of veterans prompt speculation about the health effects of DU in other exposure scenarios.

Adult↗
PubMed2001

Construction of a reference linkage map for melon.

A map of melon (Cucumis melo L.) with 411 markers (234 RFLPs, 94 AFLPs, 47 RAPDs, 29 SSRs, five inter-SSRs, and two isozymes) and one morphological trait (carpel number) was constructed using the F2 progeny of a cross between the Korean accession P1161375 and the Spanish melon type 'Pinyonet Piel de Sapo'. RFLPs were obtained using 212 probes from different genomic and cDNA melon libraries, including 16 Arabidopsis ESTs, 13 Cucumis known genes, and three resistant gene homologues. Most loci (391) mapped to 12 major linkage groups, spanning a total genetic distance of 1197 cM, with an average map interval of 3 cM/marker. The remaining 21 loci (six RAPDs and 15 AFLPs) were not linked. A majority (66%) of the markers were codominant (RFLPs, SSRs, and isozymes), making them easily transferable to other melon crosses. Such markers can be used as a reference, to merge other melon and cucumber maps already constructed. Indeed, some of them (23 SSRs, 14 RFLPs, one isozyme, and one morphological trait) could act as anchor points with other published cucurbit maps.

Chromosome Mapping↗
PubMed2000

Male and female rate differences in carpal tunnel syndrome injuries: personal attributes or job tasks?

Carpal tunnel syndrome (CTS) exacts a significant toll on the health and productivity of American workers. In 1996, 29,937 workers lost time from work due to CTS. Half of these were out for more than 25 days, compared to a median of 5 days for all injuries/illnesses. There are striking gender disparities in CTS rates. Overall, three times more women suffer from CTS than men. While some authors have emphasized the role of gender attributes in this risk disparity, the multifactoral causes of CTS, and the sex segregation of women into jobs with high-risk tasks, may be obscuring the work-related contributions to CTS risk. We argue here that men and women doing the same work tasks will have similar rates of CTS. To examine this premise, we used Bureau of Labor Statistics injury counts (numerator) and census data from the Current Population Survey (denominator) to determine injury rates of CTS for both men and women in six high-risk occupations: (1) assembler, (2) laborer-nonconstruction, (3) packaging and filling machine operators, (4) janitors and cleaners, (5) butchers and meat cutters, and (6) data entry keyers. Variable job tasks exist within five of the six high-risk occupational titles. Among those five, the male to female (M:F) risk rate ratio ranged from 0.29 to 0.50. However, the sixth occupational title, data entry keyers, which requires a single physical task, had a risk rate ratio of 1.06. This suggests that an equal risk between genders exists when the occupational tasks (exposure) are truly similar. Job task analysis unmasks potential biases that may wrongly attribute disproportionate CTS rates to gender attributes. This focus on gender attributes fails all workers because preventive interventions in the workplace are deferred. It fails women disproportionately because they are overrepresented in jobs at high risk for CTS.

Carpal Tunnel Syndrome↗
PubMed2000

Antineutrophil cytoplasmic antibodies and HLA class II alleles in minocycline-induced lupus-like syndrome.

We report 14 patients with minocycline-induced lupus-like syndrome (four men, 10 women; mean age 27.8 years) who developed a lupus-like illness after chronic use of minocycline for acne (1-10 years, median 3.8). Clinical features resolved completely on drug withdrawal (mean follow-up 11 months) and reappeared in two patients who were rechallenged. Sera from all 14 patients contained antineutrophil cytoplasmic antibodies (ANCA) giving a perinuclear pattern on indirect immunofluorescence on ethanol-fixed human neutrophils (p-ANCA), whereas 14 control asymptomatic individuals taking minocycline for acne were ANCA-negative. Eleven of the 14 patients had elevated antimyeloperoxidase antibodies and 10 had antielastase antibodies on enzyme-linked immunosorbent assay, which diminished on extended follow-up, as did other serological abnormalities. Major histocompatibility complex class II typing demonstrated that all of the 13 patients tested were either HLA-DR4 (nine of 13) or HLA-DR2 (four of 13) positive, and all had an HLA-DQB1 allele encoding for tyrosine at position 30 of the first domain. Our findings suggest a model whereby the presence of p-ANCA may be a marker for the development of lupus-like symptoms in genetically susceptible individuals taking minocycline for acne.

Adolescent↗