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Biomedical subjects

A Turner

Publications and source records attributed to A Turner.

At least 73 records · Page 4Linked to original sources
PubMed1999

Molecular epidemiology of tetM genes in Neisseria gonorrhoeae.

OBJECTIVE: To examine the epidemiology of the tetM gene in Neisseria gonorrhoeae strains with high level resistance to tetracycline (TRNG) using a polymerase chain reaction (PCR) assay. METHODS: A single tube PCR was developed which distinguishes between the American and Dutch variants of the tetM gene. Between 1988 and 1995, 518 strains of TRNG (tetracycline MIC > 8.mg/l) were referred to the Gonococcus Reference Unit by other laboratories or isolated from routine swabs taken at local clinics. The strains were analysed for plasmid content, auxotype, serovar, and the tetM gene type. Travel details of the patients were determined by a questionnaire. RESULTS: A PCR product was obtained from all TRNG examined. 387 TRNG strains produced a 778 bp PCR product (American type tetM) and 131 produced a 443 by PCR product (Dutch type tetM). Infections acquired in the United Kingdom contributed 57% of the TRNG strains included in this study; 82% of these carried the American type of tetM. The number of UK acquired TRNG received by the GRU increased each year except 1993--from four strains received in 1990 to 92 in 1995. After the United Kingdom, Caribbean and African countries contributed most strains, with 56 and 60 TRNG acquired in each area respectively. All strains originating in Africa, except one from South Africa, contained the American type tetM. Infections caught in Nigeria and Kenya contributed most strains (15 and 14 respectively). The TRNG originating from Caribbean countries comprised 36% Dutch tetM type. Infections caught in Jamaica accounted for 82% of the Caribbean strains. All 35 TRNG strains originating in the Far East contained the Dutch type tetM. 25 of the Far East strains were also penicillinase producing (PPNG). Infections originating in Indonesia accounted for 49% of the Far East strains but these belonged to 12 different auxotype/serovar combinations. A geographical variation in the type of penicillinase coding plasmids found in PPNG/TRNG was also detected. CONCLUSIONS: These data suggest that the Dutch type tetM may have originated in the Far East and the American type in the African continent. Subsequent spread has resulted in a heterogeneous distribution of TRNG types in other parts of the world. At completion of the survey the numbers of TRNG imported each year from the major overseas sources had reached a plateau while UK contracted TRNG continued to rise providing evidence for the establishment of endemic TRNG strains in the United Kingdom.

Bacterial Proteins↗
PubMed1999

Oxoid CO2 Gen atmosphere generation system for growth of capnophilic bacteria: an evaluation.

The Oxoid CO2 Gen system is compared with BBL GasPak and a carbon dioxide (CO2) incubator to evaluate its ability to support and enhance the growth of capnophilic bacteria. Clinical samples (n = 109) from various anatomical sites and 23 spiked samples are evaluated. The criteria used to compare the systems include amount of growth, colony size, colony morphology and haemolysis. Isolation rates, amounts of growth and morphology were similar in each system, but colony diameter was significantly larger in the jar-based systems. Significantly larger colonies grew in CO2 Gen than in BBL GasPak. alpha-Haemolytic zones were significantly larger in jar-based systems than in the CO2 incubator, and significantly larger in CO2 Gen than in BBL GasPak. beta-haemolytic zones were significantly larger in CO2 Gen than in the CO2 incubator. The CO2 Gen system appears to be an excellent alternative to established methods for generating an environment for capnophilic incubation.

Bacteria↗
PubMed1998

Gain of 9p in the pathogenesis of polycythemia vera.

Polycythemia vera (PV) is a clonal stem cell disorder characterized by excessive erythrocyte production, resulting in absolute erythrocytosis. No specific structural chromosomal abnormalities have been reported in PV to date. We have observed two cases of PV with an extra i(9)(p10) as the sole anomaly, and FISH analysis using a 9p-specific chromosome microdissection probe showed that two other PV patients previously identified as having an add(18p) and an add(1p) as the primary changes actually carried a der(18)t(9;18)(p12;p11.2) and a der(1)t(1;9)(p12;p12), respectively. The same FISH assay was employed to evaluate domain signals on interphase cells of 15 more cases of PV with normal karyotypes and five normal controls. Two patients were observed with a significant increase in the percentage of cells with three domain signals. Our results strongly indicate that an additional i(9)(p10) is a new and recurrent primary chromosome anomaly in PV, and, in consideration of trisomy 9 being one of the most common anomalies in PV, amplification of a gene or genes on 9p, but not on 9q, may play a crucial role in the pathogenesis of PV.

Adult↗
PubMed1998

Membrane fractionation and enrichment of callose synthase from pollen tubes of Nicotiana alata Link et Otto.

The callose synthase (UDP-glucose: 1,3-beta-D-glucan 3-beta-D-glucosyl transferase; EC 2.4.1.34) enzyme (CalS) from pollen tubes of Nicotiana alata Link et Otto is responsible for developmentally regulated deposition of the cell wall polysaccharide callose. Membrane preparations from N. alata pollen tubes grown in liquid culture were fractionated by density-gradient centrifugation. The CalS activity sedimented to the denser regions of the gradient, approximately 1.18 g.ml-1, away from markers for Golgi, endoplasmic reticulum and mitochondria, and into fractions enriched in ATPase activity and in membranes staining with phosphotungstic acid at low pH. This suggests that pollen-tube CalS is localised in the plasma membrane. Callose synthase activity from membranes enriched by downward centrifugation was solubilised with digitonin, which gave a 3- to 4-fold increase in enzyme activity, and the solubilised activity was then enriched a further 10-fold by product entrapment. The complete procedure gave final CalS specific activities up to 1000-fold higher than those of pollen-tube homogenates. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that several polypeptides co-fractionated with CalS activity through purification, with a polypeptide of 190 kDa being enriched in product-entrapment pellets.

Cell Fractionation↗
PubMed1998

Serum vitamin D metabolite levels and the subsequent development of prostate cancer (Hawaii, United States)

OBJECTIVES: Because several serum studies of vitamin D metabolites have produced equivocal results on their relation to prostate cancer risk, the purpose of this study is to evaluate this association further. METHODS: A nested case-control study in a cohort of 3,737 Japanese-American men examined from 1967 to 1970 was conducted in Hawaii (United States). At the time of examination, a single blood specimen was obtained, and the serum was frozen. After a surveillance period of over 23 years, 136 tissue-confirmed incident cases of prostate cancer were identified. Their stored sera and those of 136 matched controls were measured for the following: 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, calcium, phosphorus, and parathyroid hormone. RESULTS: There were no notable differences between cases and controls in their median serum levels of the five laboratory measurements. Odds ratios (OR) for prostate cancer, based on the quartiles of serum levels in controls, were also determined. The ORs for the highest quartiles relative to the lowest were 0.8 (95 percent confidence interval [CI] = 0.4-1.8) for 25-hydroxyvitamin D and 1.0 (CI = 0.5-2.1) for 1,25-dihydroxyvitamin D. CONCLUSION: It is possible that the lack of sufficient numbers of study subjects with low vitamin D levels affected the results. Nonetheless, the findings suggest that there is a lack of a strong association between vitamin D and prostate cancer.

Age Distribution↗
PubMed1998

Glycoproteins gB, gD, and gHgL of herpes simplex virus type 1 are necessary and sufficient to mediate membrane fusion in a Cos cell transfection system.

Herpes simplex virus type 1 glycoproteins gB, gD, and gHgL were expressed by transient transfection of Cos cells. Polykaryocyte formation above the background level seen in untransfected controls was observed only if all three components were expressed. Thus, gB, gD, and gHgL are necessary and sufficient to induce membrane fusion.

Animals↗
PubMed1997

Regional sympathetic nervous activity and oxygen consumption in obese normotensive human subjects.

BACKGROUND: Disturbed sympathetic nervous function may be of importance in obesity; sympathetic underactivity could contribute to deficient thermogenesis, positive energy balance, and weight gain, while in contrast, sympathetic nervous overactivity would predispose to the development of obesity-related hypertension. Global indices of sympathetic nervous system (SNS) function such as plasma or urinary norepinephrine (NE) have been unable to define SNS status in obesity. Since regional SNS activity can be altered in the absence of global changes, we investigated SNS activity in the heart, kidneys, and hepatomesenteric bed in healthy human subjects across a wide body mass index (BMI) range of between 19.6 and 35.5. METHODS AND RESULTS: Whole-body and regional plasma NE kinetics using [3H]-labeled NE were assessed. Regional oxygen consumption was measured by combining arteriovenous differences in oxygen content and regional blood flow. Arterial plasma NE and whole-body plasma NE spillover were unrelated to BMI. With a BMI cutoff of 27, mean cardiac NE spillover was 46% lower in the obese subjects when compared with the lean subjects (P=.017). Renal NE spillover was significantly correlated with BMI (r=.668, P=.001), the mean value in the obese subjects being more than twice that in the lean subjects. Hepatomesenteric NE spillover was comparable in lean and obese subjects. Renal and hepatomesenteric oxygen consumption were both significantly higher in the obese subjects compared with lean subjects. CONCLUSIONS: Regional SNS activity is heterogeneous in the obese state. Important regional alterations, which may be clinically relevant, occur in the absence of changes in global indices of sympathetic nervous function. The enhanced renal NE spillover in obesity may have implications for the development of hypertension in this group, whereas the low cardiac sympathetic tone would be expected to be cardioprotective. Enhanced visceral oxygen consumption evident in the kidneys and hepatomesenteric circulation in proportion to body mass contributes to the greater resting oxygen consumption in obesity.

Adolescent↗
PubMed1997

Head start.

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Humans↗
PubMed1997

Ultrastructural analysis of leaf trichome plasmodesmata reveals major differences from mesophyll plasmodesmata.

Functional studies on molecular transport through plasmodesmata in leaf mesophyll and trichome cells revealed significant differences in their basal size-exclusion limits and their response to microinjected tobacco mosaic virus movement protein (E. Waigmann et al., 1994, Proc. Natl. Acad. Sci. USA 91: 1433-1437; E. Waigmann and P. Zambryski, 1995, Plant Cell 7; 2069-2079). To address the basis for these functional differences, Nicotiana clevelandii trichome and mesophyll plasmodesmata were compared ultrastructurally. Trichome plasmodesmata increase in ultrastructural complexity from the tip to the base cell. Their neck regions, thought to control molecular traffic through plasmodesmata, are clearly distinct from necks of mesophyll plasmodesmata. In contrast to the electrondense desmotubular area in mesophyll plasmodesmata, trichome plasmodesmata contain an electron-translucent circle in their center, surrounded by an electrondense ring. This latter ring is connected to the inner leaflet of the plasma membrane by multiple spokes or filaments. Two monoclonal antibodies raised against a maize plasmodesmal protein preparation (A. Turner et al., 1994, J Cell Sci. 107: 3351-3361) interact with both trichome and mesophyll N. clevelandii plasmodesmata. Based on the localization pattern and the high degree of cross-reactivity, both antibodies likely recognize a conserved structural component of plasmodesmata, and may be useful to mark plasmodesma in a variety of plants and tissues.

Cell Communication↗
PubMed1997

Bacterial keratitis in the critically ill.

BACKGROUND: In the 4 year period (1988-91 there were nine cases of bacterial keratitis in five critically ill patients on an intensive care unit ('unit A'), all except one due to Pseudomonas aeruginosa. Many of these patients had serious ocular complications requiring surgery and all surviving patients were left with significant visual deficits. One further case of keratitis due to P aeruginosa occurred on unit A in April 1993. The problem of keratitis in ventilated patients is not unique to this unit as a further four cases in three patients from additional units in this area have been treated. METHODS: Predisposing factors in unit A were established through subsequent investigations. It was found, in particular, that all the ocular infections were preceded by colonisation of the respiratory tract with the pathogenic organism. Recommendations concerning eye care and tracheal suctioning were adopted by unit A in 1991. RESULTS: In the subsequent 4 years (1991-5), the frequency of isolation of pseudomonas from the respiratory tract per patient treated in unit A remained relatively high at 3.8% (153/4032). However, the conjunctival pseudomonas isolation rate has decreased significantly (p < 0.001) from 0.8% (19/2430) to 0.05% (2/4032). CONCLUSIONS: Ventilated patients may be at risk from inoculation of pathogens into the eyes. The principal risk factor for bacterial keratitis in this series was corneal exposure secondary to conjunctival chemosis or lid damage. The adoption of simple preventative measures on unit A had a significant impact on the incidence of eye infections due to pseudomonas, despite the high proportion of patients whose respiratory tracts were colonised with the same organism. There is a need for additional research into the most effective method of eye care for ventilated patients in order to reduce the frequency of this avoidable condition.

Critical Care↗
PubMed1997

Developing sexual health software incorporating user feedback: a British experience.

This article describes an interactive prototyping model for development of four computer software modules for British youth on sexual issues. An iterative cycle of development, user review and feedback, and subsequent modification and retesting was used with approximately 150 young adults, with particular attention to presentation style, screen design, usability, relevance of material, enjoyment, and learning. The software was designed to be realistically accommodated in school settings, to be used as a reference tool by students working alone or in a group teaching situation. Feedback from youth and adults attests to the feasibility of development, implementation, and instructional usefulness. Interactive prototyping proved essential in the face of skepticism from teachers concerning young people's information needs and acceptance of a computerized educational approach.

Adolescent↗
PubMed1997

The role of athletic trainers in counseling collegiate athletes.

OBJECTIVE: To assess athletic trainers' perceptions with regard to (a) their role in counseling athletes, (b) how qualified they felt to address counseling issues, and (c) current training room procedures for providing psychological services to athletes. DESIGN AND SETTING: A 47-item, open-ended survey was administered to Division I certified athletic trainers who volunteered to participate. SUBJECTS: Fourteen Division I certified athletic trainers (mean age, 33 yr; range, 24 to 47 yr) volunteered to participate in the survey. They included five head athletic trainers, five assistant athletic trainers, three graduate assistants, and one associate director of athletics and sports medicine. MEASUREMENTS: Survey results were tabulated and reported in percentages. RESULTS: Athletic trainers felt that their roles went beyond the care and prevention of athletic injuries, yet they did not necessarily feel qualified to counsel athletes. Most athletic trainers were familiar with on-campus student support services to which student athletes with personal issues could be referred for assistance, but none had access to a sport psychologist. CONCLUSIONS: It is recommended that the NATA include counseling preparation in curriculums and that continuing education be offered to provide certified athletic trainers with current information and skills for delivering psychological services to athletes.

Journal Article↗