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D Wray

Publications and source records attributed to D Wray.

At least 19 recordsLinked to original sources
PubMed2000

In vitro resistance to thrombin-induced platelet microbicidal protein in isolates of Staphylococcus aureus from endocarditis patients correlates with an intravascular device source.

Platelet microbicidal proteins (PMPs) are small antimicrobial peptides secreted by mammalian platelets. In vitro resistance of Staphylococcus aureus strains to PMPs correlates with more extensive disease in experimental infective endocarditis (IE). To determine whether this same relationship exists in human S. aureus IE, we evaluated the in vitro PMP susceptibility phenotype of isolates from 58 prospectively-identified patients with definite S. aureus IE. On multivariate analyses, patients with S. aureus IE complicating an infected intravascular device were significantly more likely to have IE caused by a PMP-resistant strain (P=.0193). No correlations were detected between in vitro PMP resistance among S. aureus strains and the severity of human IE. This work supports the concept that in vitro PMP resistance in clinical S. aureus strains is associated with important clinical characteristics of S. aureus endovascular infections in vivo.

Analysis of Variance↗
PubMed2000

Regulation of cloned cardiac L-type calcium channels by cGMP-dependent protein kinase.

We have studied the effect of 8-bromo-cyclic GMP (8-Br-cGMP) on cloned cardiac L-type calcium channel currents to determine the site and mechanism of action underlying the functional effect. Rabbit cardiac alpha(1C) subunit, in the presence or absence of beta(1) subunit (rabbit skeletal muscle) or beta(2) subunit (rat cardiac/brain), was expressed in Xenopus oocytes, and two-electrode voltage-clamp recordings were made 2 or 3 days later. Application of 8-Br-cGMP caused decreases in calcium channel currents in cells expressing the alpha(1C) subunit, whether or not a beta subunit was co-expressed. No inhibition of currents by 8-Br-cGMP was observed in the presence of the protein kinase G inhibitor KT5823. Substitutions of serine residues by alanine were made at residues Ser(533) and Ser(1371) on the alpha(1C) subunit. As for wild type, the mutant S1371A exhibited inhibition of calcium channel currents by 8-Br-cGMP, whereas no effect of 8-Br-cGMP was observed for mutant S533A. Inhibition of calcium currents by 8-Br-cGMP was also observed in the additional presence of the alpha(2)delta subunit for wild type channels but not for the mutant S533A. These results indicate that cGMP causes inhibition of L-type calcium channel currents by phosphorylation of the alpha(1C) subunit at position Ser(533) via the action of protein kinase G.

Alkaloids↗
PubMed2000

Local movement in the S2 region of the voltage-gated potassium channel hKv2.1 studied using cysteine mutagenesis.

The positively charged S4 region of voltage-dependent potassium channels moves outward during depolarization, leading to channel opening, but possible movement of the negatively charged S2 region may be more complex. Here we have studied possible movement of the S2 region of the slowly activating human voltage-dependent potassium channel hKv2.1. For this, cysteine mutants in the S2 region were expressed in Xenopus oocytes by injection of cRNA. Whole-cell currents were measured using the two-electrode voltage-clamp technique, and the effect of the membrane-impermeable cysteine-binding reagent parachloromercuribenzenesulfonate (PCMBS) was studied. For mutant S223C (located just outside the membrane in the S2 region), PCMBS inhibited currents and caused faster deactivation of tail currents. The time course of reactivity of PCMBS on tail current amplitudes was faster at more negative holding potentials. There was no effect of PCMBS on potassium channel currents for mutants D225C, N226C, A230C, and V232C. These data suggest that residue S223 is exposed to the extracellular phase at normal resting potentials, making it accessible to PCMBS, but upon depolarization there is a conformational change, making it less accessible, possibly by a local rather than global movement of S2 residues into the membrane. Voltage-dependent movements of nearby residues could also explain the results.

4-Chloromercuribenzenesulfonate↗
PubMed2000

Lack of association between Streptococcus oralis and recurrent aphthous stomatitis.

In the present study, the potential involvement of Streptococcus oralis in the aetiology of recurrent aphthous stomatitis (RAS) was investigated using the polymerase chain reaction (PCR). Biopsies from 28 RAS patients were analysed, in addition to 20 oral lichen planus (OLP) and 13 normal biopsies that were used as controls. PCR was carried out using a primer pair that targets the D-alanine:D-alanine ligase gene and detects DNA from both S. oralis and the closely related species Streptococcus mitis. Discrimination between these two species was achieved by digestion of PCR products with the restriction endonucleases HaeIII and HindIII, which both give distinct restriction profiles for each species. S. oralis DNA was detected in 8 of 28 (29%) RAS samples, 10 of 20 (50%) OLP samples and 6 of 13 (46%) normal samples. These results suggest that S. oralis is not of primary aetiological significance in RAS.

Adult↗
PubMed2000

Detection of Helicobacter pylori DNA in recurrent aphthous stomatitis tissue by PCR.

Helicobacter pylori is recognised as being an aetiological agent of chronic active gastritis and peptic ulcer disease and has been associated with an increased risk of gastric cancer. The natural reservoir for H. pylori is unknown, although the oral cavity has been the focus of much attention in this respect. Given the histological similarities between gastric and oral ulceration, it seemed prudent to investigate a possible association between H. pylori and recurrent aphthous stomatitis (RAS). In this study, the potential involvement of H. pylori in the aetiology of RAS was investigated using the polymerase chain reaction (PCR). Biopsies from 28 RAS patients were analysed, in addition to 20 oral lichen planus (OLP) and 13 normal biopsies that were used as controls. Genomic DNA was extracted from biopsies, and confirmation of successful extraction of PCR-amplifiable DNA was achieved by carrying out PCR on each DNA sample with nested primers specific for the human beta-haemoglobin gene. PCR identification of H. pylori was carried out using a primer pair specific for the H. pylori 16S ribosomal RNA (rRNA) gene. Two rounds of PCR were carried out to amplify a 295-bp product, and the identity of amplified products was confirmed by DNA sequencing. H. pylori DNA was detected in 3 of 28 (11%) RAS samples but not in any of 20 OLP and 13 normal samples. These results do not support a definitive aetiological role for H. pylori in RAS, although the possibility that H. pylori may be involved in a small proportion of RAS cases cannot be excluded.

Adult↗
PubMed2000

Oral staphylococcal mucositis: A new clinical entity in orofacial granulomatosis and Crohn's disease.

OBJECTIVE: Orofacial granulomatosis and the oral manifestations of Crohn's disease comprise many clinical features, of which stomatitis is one. The purpose of this study was to establish a role for Staphylococcus aureus in mucositis affecting some patients with orofacial granulomatosis or oral Crohn's disease. STUDY DESIGN: Four patients (2 with orofacial granulomatosis and 2 with oral Crohn's disease), from a total of 450 patients examined over 10 years, had stomatitis involving the entire oral mucosa, from which S aureus was cultured by the oral rinse technique. These patients were treated with flucloxacillin or erythromycin. RESULTS: A heavy growth of S aureus was isolated from the mouth of each patient. All 4 patients responded to treatment with flucloxacillin or erythromycin. CONCLUSIONS: S aureus is a potential cause of panstomatitis in patients with orofacial granulomatosis or Crohn's disease. This infection responds rapidly to antimicrobial treatment.

Adolescent↗
PubMed2000

The role of allergy in oral mucosal diseases.

We retrospectively assessed the prevalence of positive results to cutaneous patch testing, and the relevance of exclusion of identified allergens in the disease process, in 1252 patients with oral mucosal diseases presenting to the Department of Oral Medicine in Glasgow Dental Hospital and School and referred to the Contact Dermatitis Investigation Unit in Glasgow Royal Infirmary. The prevalence of patch-test positivity in each disease cohort was compared with that in 100 control volunteers. Patients with oral mucosal diseases were significantly more likely to have demonstrable hypersensitivity to food additives, especially benzoic acid, and perfumes and flavourings, especially cinnamaldehyde, than controls, and avoidance therapy caused improvement in the majority. Patch testing and the resultant avoidance therapy are useful adjuncts in the management of oral mucosal diseases.

Adolescent↗
PubMed1999

Effect of cysteine substitutions on the topology of the S4 segment of the Shaker potassium channel: implications for molecular models of gating.

1. The gating properties of voltage-gated potassium channels are largely determined by the amino acid sequence of their S4 segments. To investigate the nature of S4 movement during gating, we introduced single cysteines into the S4 segment of the Shaker potassium channel and expressed the mutants in Xenopus oocytes. We then measured the conductance-voltage (g-V) relationships and the rate and the voltage dependence of movement of the engineered cysteines, using p-chloromercuribenzene sulphonate (pCMBS) as a probe. 2. Mutation of charged residues at positions 362, 365 and 368, but not the uncharged residues (positions 360, 361, 363, 364 and 366), to cysteines shifted the g-V relationships to more positive potentials. Mutant channels in which cysteines replaced the charged residues at positions 362 and 365 (R362C and R365C) reacted faster with pCMBS than those in which cysteines were introduced in place of uncharged residues at positions 360 and 361 (I360C and L361C). Furthermore, the R365C mutant channel reacted with pCMBS even at hyperpolarised (-120 mV) potentials. Currents expressed by the doubly mutated R365S/V367C and R368S/V367C channels, but not the singly mutated V367C channel, were inhibited by pCMBS. Moreover, the R368C mutant channel was also affected by pCMBS. 3. Voltage dependence of block by pCMBS (2 min exposure) was steeper for L366C than for L361C and V363C mutant channels (effective charge 2.19, 1. 41 and 1.45, respectively). The voltage dependence of the pCMBS effect was also shifted to more depolarising potentials the deeper in the membrane the position of the residue mutated to cysteine (voltages for half-maximal effect -107, -94 and -73 mV for positions 361, 363 and 366, respectively). 4. Our data show firstly that charge-neutralising mutations in S4 alter the topology of this region such that the membrane-spanning portion of S4 is reduced. Secondly, our data for the other mutant channels suggest that S4 might move in at least two sequential steps, and can move up to its maximal limit even at the resting potential of the cell.

Amino Acid Substitution↗
PubMed1999

Emergency drugs.

Explore the source record for details and available documents.

Emergency Medical Services↗
PubMed1999

Conserved extracellular cysteine residues in the inwardly rectifying potassium channel Kir2.3 are required for function but not expression in the membrane.

The mouse potassium channel Kir2.3 possesses conserved extracellular cysteine residues at positions 113 and 145. We have investigated the role of these cysteines in structure/function and membrane trafficking. Cysteine to serine mutations resulted in the absence of potassium currents in oocytes and co-expression of these mutants with wild-type channel showed a dominant negative inhibition of wild-type currents. FLAG-tagged channels expressed in oocytes were detected in the cell membrane by anti-FLAG antibody for wild-type and mutant channels. In vitro translation using the reticulocyte lysate system showed that mutation of these residues did not affect processing nor insertion into membranes. Cysteine residues at 113 and 145 are therefore required for function of the Kir2.3 channel but not for processing into the cell membrane; disulfide bonds between subunits are unlikely.

Animals↗
PubMed1999

Functional and molecular aspects of voltage-gated K+ channel beta subunits.

Voltage-gated potassium channels (Kv) of the Shaker-related superfamily are assembled from membrane-integrated alpha subunits and auxiliary beta subunits. The beta subunits may increase Kv channel surface expression and/or confer A-type behavior to noninactivating Kv channels in heterologous expression systems. The interaction of Kv alpha and Kv beta subunits depends on the presence or absence of several domains including the amino-terminal N-type inactivating and NIP domains and the Kv alpha and Kv beta binding domains. Loss of function of Kv beta 1.1 subunits leads to a reduction of A-type Kv channel activity in hippocampal and striatal neurons of knock-out mice. This reduction may be correlated with altered cognition and motor control in the knock-out mice.

Alternative Splicing↗
PubMed1999

The effects of oxidizing and cysteine-reactive reagents on the inward rectifier potassium channels Kir2.3 and Kir1.1.

The inwardly rectifying potassium channel Kir2.3 possesses extracellular cysteine residues at positions 113, 140, and 145, as well as at position 79 near the outer membrane boundary. In this study, we have investigated the roles of these extracellular cysteine residues in mediating inhibition of the Kir2.3 channel by the cysteine-reactive reagents para-chloromercuribenzenesulphonate (PCMBS) and thimerosal, and the oxidizing agent hydrogen peroxide (H2O2). We have also compared the effects of these reagents with those on Kir1.1 channels (which do not possess cysteine residues equivalent to 140 and 79 in Kir2.3 channels). Mutant channels were made in which cysteine residues were mutated to serine by site-directed mutagenesis. Wild-type or mutant cRNA was injected into Xenopus oocytes and voltage-clamp recordings made 1-2 days later. Wild-type Kir2.3 currents were significantly inhibited by PCMBS, thimerosal and H2O2. Currents for mutants Kir2.3 C79S and C140S were also inhibited by PCMBS, thimerosal and H2O2. These mutations affected the time course of inhibition by all three reagents. For PCMBS, a slow component of inhibition was absent for the C79S mutation, and a fast component was absent for C140S. For the double mutation C79S/C140S, PCMBS no longer had any effect. For thimerosal, there was a slower time course for C140S, a faster time course for C79S, and a delayed onset for C79S/C140S. For H2O2, the main effect was a delayed onset for the double mutant. The reducing agent dithiothreitol (DTT) reversed the inhibition by both PCMBS and thimerosal of wild-type and mutant currents, but not the inhibition due to H2O2. Finally, wild-type Kir1.1 currents were not significantly inhibited by the applications of either PCMBS or thimerosal, while H2O2 produced small inhibition. The results taken together indicate that inhibition by the cysteine-reactive reagent PCMBS is mediated through cysteine residues 79 and 140 in Kir2.3 channels, with C79 mediating a slow component of inhibition and C140 a faster component, and that both residues are extracellularly exposed. The data indicate that these two cysteine residues are also main sites for inhibition by thimerosal and H2O2 but, unlike for PCMBS, an additional non-extracellular inhibitory site(s) must also be involved.

4-Chloromercuribenzenesulfonate↗
PubMed1999

Detection of serum antibodies against cytomegalovirus, varicella zoster virus and human herpesvirus 6 in patients with recurrent aphthous stomatitis.

There has recently been renewed interest in the possible role of viruses in recurrent aphthous stomatitis (RAS). In this study, sera from 22 patients with RAS, 24 patients with oral lichen planus (OLP) and 15 healthy controls were screened for IgG and IgM class antibodies to human cytomegalovirus (HCMV), varicella zoster virus (VZV) and human herpesvirus 6 (HHV-6). Commercially available ELISA and immunofluorescence kits were employed. There were no significant differences in the prevalence of IgG antibodies to HCMV, VZV or HHV-6 among the three patient groups. Similarly, there were no significant differences between the prevalence of HCMV and VZV IgM antibodies among RAS patients and controls. However, specific HHV-6 IgM was detected in 21 (95%) of the RAS patients and 17 (71%) of the lichen planus patients compared with 8 (53%) of the healthy controls. This difference between RAS patients and controls was statistically significant (P<0.01). These results do not support an aetiological role for HCMV or VZV in RAS but suggest possible involvement of HHV-6.

Adult↗
PubMed1998

A vision-based three-dimensional capture system for maxillofacial assessment and surgical planning.

We describe a vision-based three-dimensional facial data capture system designed for the planning of maxillofacial operations. We describe the system requirements and outline the methods used to develop a complete three-dimensional facial capture system. Our approach is based upon imaging the face using two stereo-pair sets of cameras. Scale-space-based stereo-matching is then used to recover correspondences between each of the captured stereo-pairs. Photogrammetric routines based on adjustment of bundles are used off-line to calibrate the system by imaging a single object that references all cameras to the same co-ordinate frame. This calibration scheme allows us to convert stereo correspondences to world points for each pair of cameras without the need for any subsequent fusion of data. Initial results show that we are able to capture key facial landmarks to within 0.5 mm.

Algorithms↗
PubMed1998

A comparison of fluconazole and itraconazole in the management of denture stomatitis: a pilot study.

OBJECTIVES: To compare fluconazole capsules (50 mg daily for 14 days) and itraconazole capsules (100 mg daily for 15 days) in the treatment of denture stomatitis, using objective clinical and mycological outcome measures. METHODS: Twenty complete denture wearers with denture stomatitis were enrolled. At baseline, palatal erythema was measured with an electro-optical instrument, a denture disc specimen was collected from the fitting surface of the denture for culture and an oral rinse and imprint cultures were collected for mycological culture. Ten patients received fluconazole capsules (50 mg daily for 14 days) and 10 received itraconazole capsules (100 mg daily for 15 days). Palatal erythema was reassessed and the microbiological specimens re-collected on day 14. RESULTS: The most common form of denture stomatitis seen in this group of patients was Newton's Type II. All patients responded to advice to leave their dentures out at night but there was a poor overall improvement in denture hygiene. There was an objective reduction in palatal erythema following treatment with both fluconazole and itraconazole. A wide range of yeasts were isolated from the mouths of all the denture stomatitis patients before treatment. C. albicans was the most common isolate. A mycological cure was achieved in only five of the 20 patients, one in the fluconazole group and four in the itraconazole group. A further eight patients in the fluconazole group and three in the itraconazole group had reduced yeast counts by the second visit. CONCLUSION: Fluconazole and itraconazole were of comparable efficacy in the treatment of denture stomatitis, on the basis of reduction in palatal erythema and mycological culture.

Adult↗
PubMed1998

A controlled study of gold contact hypersensitivity.

1203 patients attending for routine patch testing at 3 hospitals and 105 volunteers were tested with 0.5% and 0.05% gold sodium thiosulfate (GST). 38 patients (3.2%) and 5 volunteers (4.8%) had positive patch tests to GST. There were no significant differences between volunteers and patients with respect to age, sex, atopy or exposure to gold in dental restorations, jewellery or through occupation. There were no significant differences in prevalence of GST hypersensitivity in the 3 hospitals, or between patients and controls. This is the 1st controlled study of hypersensitivity to GST, and suggests that routine patch testing to gold is of limited clinical benefit.

Adolescent↗