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Biomedical subjects

S Wood

Publications and source records attributed to S Wood.

At least 37 records · Page 2Linked to original sources
PubMed2001

Measurement of the electric form factor of the neutron through d-->(e-->,e(')n)p at Q2 = 0.5 (GeV/c)(2).

We report the first measurement using a solid polarized target of the neutron electric form factor G(n)(E) via d-->(e-->,e(')n)p. G(n)(E) was determined from the beam-target asymmetry in the scattering of longitudinally polarized electrons from polarized deuterated ammonia ( 15ND3). The measurement was performed in Hall C at Thomas Jefferson National Accelerator Facility in quasifree kinematics with the target polarization perpendicular to the momentum transfer. The electrons were detected in a magnetic spectrometer in coincidence with neutrons in a large solid angle segmented detector. We find G(n)(E) = 0.04632+/-0.00616(stat)+/-0.00341(syst) at Q2 = 0.495 (GeV/c)(2).

Journal Article↗
PubMed2001

Measurement of the charged pion electromagnetic form factor.

Separated longitudinal and transverse structure functions for the reaction 1H(e,e(')pi(+))n were measured in the momentum transfer region Q2 = 0.6--1.6 (GeV/c)(2) at a value of the invariant mass W = 1.95 GeV. New values for the pion charge form factor were extracted from the longitudinal cross section by using a recently developed Regge model. The results indicate that the pion form factor in this region is larger than previously assumed and is consistent with a monopole parametrization fitted to very low Q2 elastic data.

Journal Article↗
PubMed2001

The use of a lymphatic bridge in the management of head and neck lymphoedema.

Severe progressive lymphoedema of the whole of the head and neck is almost always due to the combined effects of surgery and radiotherapy, compounded by repeated infections or recurrent tumour. The condition is difficult to control, and manual lymphatic drainage is the mainstay of management. We present a case of progressive lymphoedema following treatment for an occult squamous carcinoma of the head and neck, and describe the use of a lymphatic bridge to drain the facial tissue.

Carcinoma, Squamous Cell↗
PubMed2001

Sedation and analgesia for transvaginal oocyte retrieval: an audit resulting in a change of clinical practice.

The aim was to audit the standard of care at oocyte retrieval with respect to the analgesia used. Before June 1999, a combination of intramuscular pethidine and prochlorperazine was given as a single dose. Many women found this to be unsatisfactory and requested general anaesthesia for subsequent oocyte retrievals. An intravenous sedation and analgesia regimen was introduced using a combination of midazolam and fentanyl. The introduction of this regimen was audited and compared with the established regimen. This study describes the experience with this technique, its patient acceptability, safety and cost implications.

Analgesics↗
PubMed2001

Generation and characterization of monoclonal antibodies to the neural crest.

The generation of monoclonal antibodies (MAbs) specific for quail neural crest may provide valuable tools for studying the differentiation of embryonic precursor cells. Unfortunately, relatively few antibodies are available because of the difficulty in obtaining sufficient cells for in vivo immunization strategies. We have overcome this problem by using intrasplenic immunization with formaldehyde-fixed cells harvested from neural crest cultures. In addition, booster injections of cultured whole-embryo cells were administered intraperitoneally. Following two fusions, a total of 18 hybridomas were generated with antibody reactivity to the cytoplasm of neural crest cells. Furthermore, 32 were reactive against both somite (a noncrest mesodermal control) and crest cultures, whilst 15 were not reactive. Out of those hybridomas reactive with neural crest, six designated 160D, 164D, OE, 12E, 120E and 124E were further characterized. Interestingly MAb supernatants OE, 12E, 120E, and 124E exhibited reactivity against some but not all neural crest cells suggesting that they might recognise subpopulations. Immunoglobulin isotyping of supernatants revealed that 4 (160D, 164D, OE, and 120E) were IgM and 2 (12E and 124E) were IgG(2b). On assessing their reactivity against human tissue sections, all six hybridoma supernatants cross-reacted with neuroendocrine cells within appendix, colon and rectum. These MAbs could provide novel reagents for the understanding of neural crest development.

Animals↗
PubMed2001

Measurement sensitivity and the Minimum Data Set depression quality indicator.

PURPOSE: The purpose of this study was to determine the accuracy of the prevalence rating of depression in nursing homes as flagged on the Minimum Data Set (MDS) quality indicator report. DESIGN AND METHODS: Research Staff measured depression symptoms and compared the results with the prevalence of disturbed mood symptoms documented by nursing home (NH) staff on the MDS in two samples of residents living in different NHs. The homes had been flagged on the nationally mandated MDS quality indicator report as having unusually low (Site 1) or high (Site 2) prevalence rates of depression. RESULTS: The percentages of residents determined by research staff interview assessments to have probable depression in the two resident samples were not significantly different (49% vs. 55%, respectively) between homes. The staff in the home flagged on the MDS quality indicator report as having a high depression prevalence rate identified significantly more residents who also had scores indicative of probable depression on the resident interviews for follow-up mood assessments than did the home with a low quality indicator prevalence rate (78% vs. 25%, respectively). IMPLICATIONS: The prevalence of the depression quality indicator may be more reflective of measurement processes than of depression outcomes. Factors that may affect the difference in detection rates are discussed.

Aged↗
PubMed2001

Structure-function studies of an IGF-I analogue that can be chemically cleaved to a two-chain mini-IGF-I.

The structure and biological activities of two disulphide isomers of a C-region deletion mutant of insulin-like growth factor-I (IGF-I) which has an Asn--Gly link engineered at the junction of the A- and B-regions were studied before and after chemical cleavage. Circular dichroism (CD) spectra and binding affinity to IGF binding protein 3 (IGFBP3) indicated that the treatment with hydroxylamine did not disrupt the overall tertiary fold of the hormones. Cleavage restored some binding affinity for the IGF-I receptor in both isomers and weakly restored the ability to stimulate incorporation of tritiated thymidine into DNA in NIH 3T3 fibroblasts transfected with the human IGF-I receptor. Cleavage also restored metabolic capacity, as measured by the ability of the isomers to promote lipogenesis in isolated rat adipocytes through the insulin receptor. These results are consistent with the theory that binding of IGF-I to the IGF-I receptor requires a conformational change similar to that involved in insulin binding the insulin receptor. The weak affinity for the IGF-I receptor after cleavage is consistent with the belief that residues in the C-region interact with the IGF-I receptor. This structural difference between insulin and IGF-I gives each a higher binding affinity for its own receptor.

3T3 Cells↗
PubMed2001

Antibiotic activity and characterization of BB-3497, a novel peptide deformylase inhibitor.

Peptide deformylase (PDF) is an essential bacterial metalloenzyme which deformylates the N-formylmethionine of newly synthesized polypeptides and as such represents a novel target for antibacterial chemotherapy. To identify novel PDF inhibitors, we screened a metalloenzyme inhibitor library and identified an N-formyl-hydroxylamine derivative, BB-3497, and a related natural hydroxamic acid antibiotic, actinonin, as potent and selective inhibitors of PDF. To elucidate the interactions that contribute to the binding affinity of these inhibitors, we determined the crystal structures of BB-3497 and actinonin bound to Escherichia coli PDF at resolutions of 2.1 and 1.75 A, respectively. In both complexes, the active-site metal atom was pentacoordinated by the side chains of Cys 90, His 132, and His 136 and the two oxygen atoms of N-formyl-hydroxylamine or hydroxamate. BB-3497 had activity against gram-positive bacteria, including methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus faecalis, and activity against some gram-negative bacteria. Time-kill analysis showed that the mode of action of BB-3497 was primarily bacteriostatic. The mechanism of resistance was via mutations within the formyltransferase gene, as previously described for actinonin. While actinonin and its derivatives have not been used clinically because of their poor pharmacokinetic properties, BB-3497 was shown to be orally bioavailable. A single oral dose of BB-3497 given 1 h after intraperitoneal injection of S. aureus Smith or methicillin-resistant S. aureus protected mice from infection with median effective doses of 8 and 14 mg/kg of body weight, respectively. These data validate PDF as a novel target for the design of a new generation of antibacterial agents.

Amidohydrolases↗
PubMed2001

Improving referrals for glue ear from primary care: are multiple interventions better than one alone?

OBJECTIVES: To evaluate the effect of a risk factor checklist and training video for general practitioners in reducing inter-practice variation and improving the appropriateness of referrals (assessed by their positive predictive value or PPV) of patients with suspected otitis media with effusion (OME or 'glue ear') to secondary care. METHODS: Fifty general practices (177 practitioners) from the NHS Trent region and the West of Scotland were cluster-randomised either to a control group (n = 12) or to one of three intervention groups (training video (n = 16), checklist (n = 11), or both (n = 11)). Data on all paediatric ear, nose and throat (ENT) referrals and diagnostic results at ENT clinics were collected for a one-year period pre- and post-intervention. Referral rates for OME and for closely related conditions were calculated for children aged 0-15 years, based on each practice's list size. PPV was defined as the proportion of referrals resulting in bilateral hearing loss > or = 20 dB at the ENT outpatient department. RESULTS: There was a significant improvement in the PPV, adjusted for patients' waiting time between general practitioner (GP) referral and being seen at the ENT department. The improvement in PPV pre- and post-intervention was 15% (95% confidence interval, CI: -12.1% to 41.7%) for the practices receiving both interventions, compared with a degradation of 20% pre- and post-intervention (95% CI: -32.9% to -6.4%) for practices receiving only one intervention and a degradation of 34% for those receiving no intervention. CONCLUSIONS: Disseminating a risk factor checklist and training video on glue ear to GPs using a multi-channel approach can improve the quality of referrals to ENT.

Adolescent↗
PubMed2001

Management of obesity with the new intragastric balloon.

BACKGROUND: The introduction of an endoscopically-placed Bariatric Intragastric Balloon (BIB) provided the opportunity to reexamine weight reduction methods and also study potential weight loss without resorting to surgical intervention. METHODS: 10 severely obese patients with mean age 33 years and mean body mass index 39, underwent BIB placement, 7 as a sole weight reduction procedure and 3 requiring weight reduction before repair of large incisional hernias. All patients were followed at 2-week intervals by a nurse practitioner and dietitian for 6 months. RESULTS: Mean weight loss was 18.6 kg (range 6.6-40.0), equivalent to 40% excess weight loss (EWL), range 10-81%. EWL was 54% (29-81%) in those patients who had two balloons placed, who lost an average of 30.3 kg (24.0-40.0 kg). In the patients who had only one balloon placed, mean weight loss was 10.4 kg (8.8-12.5), equal to an EWL of 19% (10-37%). CONCLUSION: These results lead us to consider BIB placement as a successful short-term measure for weight loss or for patients requiring at least weight loss before other surgery.

Adult↗
PubMed2001

Reducing falls risk.

A multidisciplinary working group in a London hospital set up a questionnaire system to reduce patient falls. The framework it put in place is now a way of life at the hospital and could provide the basis for a wider Clinical Governance project.

Accident Prevention↗
PubMed2000

The HMG box transcription factor gene Sox14 marks a novel subset of ventral interneurons and is regulated by sonic hedgehog.

Cell-type diversity along the dorsoventral axis of the developing neural tube is influenced by factors secreted by groups of cells at the dorsal and ventral midline. Upon reception of these signals, precursor cells express specific sets of transcription factors which, in turn, play critical roles in cell-type specification. Here we report the cloning and characterization of Sox14, a novel and highly conserved member of the Sry-related Sox transcription factor gene family, in mouse and chick. Sox14 expression is restricted to a limited population of neurons in the developing brain and spinal cord of both species. Sox14 marks a subset of interneurons at a defined dorsoventral position adjacent to ventral motor neurons in the spinal cord. In vivo grafting of chick notochord tissue to ectopic positions adjacent to the developing spinal cord altered the expression domain of Sox14. Furthermore, expression of Sox14 in spinal cord explants was found to be regulated by Sonic hedgehog in a dose-dependent manner. These data implicate a novel class of transcription factors in dorsoventral cell-type specification in the spinal cord.

Amino Acid Sequence↗
PubMed2000

Selective attention fails to alter the dichotic listening lag effect: evidence that the lag effect is preattentional.

Berlin et al. (1973) reported that either stimulus from a dichotic pair of consonant-vowel syllables is processed preferentially when its presentation is delayed by 30-60 ms. In the first of three experiments with 60 normal right-handed adults, we replicated the Berlin et al. "lag effect," but only for asynchronies between 60 and 90 ms. In Experiment 2 subjects focused attention selectively on one ear. The results indicated that focused attention and stimulus asynchrony have additive effects: Performance improved at the attended ear irrespective of stimulus asynchrony, but the lag effect remained unchanged relative to the divided-attention condition. Experiment 3 entailed a signal detection task that allowed separate analysis of detection and localization accuracy. As in previous studies, selective attention to one ear increased the accuracy of localization but not detection at the attended ear. Both dependent measures indicated a lag effect that remained invariant as attention was manipulated. These findings imply that the lag effect is attributable to a preattentional stage of auditory processing.

Adult↗
PubMed2000

Integrated systems to reduce length of stay for knee and hip joint replacement surgeries.

To reduce length of stay while maintaining quality of care, St. Joseph's Hospital, Hamilton, ON implemented a care path with three discharge options. Two of these discharge options were early discharge to integrated community services. Patients meeting early discharge criteria are discharged home five days post-operatively with follow-up by home care nursing and physiotherapy. Otherwise, patients are discharged on day four to a multi-disciplinary rehabilitation unit at a separate facility. Patients requiring acute medical services for complications or co-morbidity stay in the acute care hospital. A prospective cohort evaluation showed no difference in complications and similar functional outcomes for the three discharge options.

Arthroplasty, Replacement, Hip↗
PubMed2000

A model to quantify encrustation on ureteric stents, urethral catheters and polymers intended for urological use.

OBJECTIVE: To validate an encrustation model and to quantify encrustation on currently used urological devices and polymers intended for urological use. Materials and methods An encrustation model was validated: (i) to measure the amount of calcium leaching from the glass model and from the polymer used; (ii) to determine whether the use of a single-source or pooled urine produced similar results; (iii) to determine in vitro encrustation; and (iv) to compare the results of in vivo implantation of the same materials into the bladders of rodents with the in vitro results. A test polymer (a ureteric stent, a urethral catheter or a biomaterial) and a control silicone polymer were housed separately but received human urine from the same reservoir and under the same conditions (pH 6.0 and 37 degrees C) for 5 days. The amount of calcium encrustation on each polymer was measured using atomic absorption spectroscopy. Each experiment was repeated at least four times and the results expressed as an encrustation index, defined as the ratio of encrustation of the test and reference polymers. RESULTS: The amount of calcium leaching from the glass model and polymers tested was insignificant. The use of a single-source or pooled urine gave the same results in the encrustation model. The in vitro results correlated with in vivo implantation of disks into the bladders of rats. Among the commonly used ureteric stents tested, the Cook C-Flex ureteric stents encrusted least. Hydrogel-coated ureteric stents encrusted more than uncoated stents. The Bard polytetrafluoroethylene short-term urethral catheter encrusted more than the Bard hydrogel-coated long-term catheter. A plasma-activated surface modification of a synthetic biomaterial with hyaluronic acid encrusted less than silicone, a long-term biomaterial widely regarded as the 'gold standard'. CONCLUSION: This validated encrustation model is the first to quantify encrustation on currently available ureteric stents and urethral catheters. A novel coating for a biomaterial was identified using the encrustation model, and which encrusted less than silicone.

Animals↗