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Biomedical subjects

D Wray

Publications and source records attributed to D Wray.

At least 55 records · Page 3Linked to original sources
PubMed1994

Occupational risk and precautions related to HIV infection among dentists in the Lothian region of Scotland.

This retrospective study used a postal questionnaire to measure occupational risks and to assess infection control procedures among 310 dental practitioners. The study comprised general dental practices in the Lothian region of Scotland, Lothian Health Board Community Dental Service and Edinburgh Dental Hospital. Altogether, 217 dental practitioners responded by the due date giving recall of inoculation injuries within the previous 5 years and infection control measures employed. The study revealed that 191 practitioners (88%) had completed a course of hepatitis B vaccination but one-third of them had not been tested for post-vaccination antibody. In 1991, two thirds of dentists (66%: 137 of 207 respondents) wore the same pair of gloves, and 80% of dentists (142 of 177 respondents) wore the same mask, for dealing with more than one patient. The usual practice was to change gloves during sessions (44%: out of 71 dentists) and to change masks for each session or less often (75%: 73 out of 97 dentists). The proportion of dentists who never used gloves fell from 56% in 1981 to 1% in 1991. An autoclave was used for sterilisation by 85% of practitioners in 1991. Reported non-sterile inoculation injuries averaged 1.7 (S.D. = 3.2) injuries per dentist in the previous year with 56% of practitioners having had an injury. The average was 6.8 (S.D. = 15.9) injuries per dentist in the previous 5 years with 76% of practitioners having had an injury. Of recent non-sterile inoculation injuries described by dental practitioners, 30% constituted a moderate or high risk of transmission of infection to the practitioner (43 of 141 described injuries). Combined with HIV seroprevalance rates, probabilities of transmission and numbers of practising dentists, the mean reported number of non-sterile inoculation injuries in the previous 5 years may be used to provide estimates of expected numbers of dental practitioners occupationally infected with HIV in the previous 5 years. U.K. estimates were 0.004 dentists in Lothian region and 0.05 dentists in the Thames region occupationally infected with HIV in the previous five years. Non-sterile inoculation injuries appear to be a common hazard of dental practice. In any year, most dentists are exposed to the risk of blood-borne viral infection. Despite a high reported incidence of such injuries, dental practice within the U.K. appears to carry a low risk of acquiring HIV infection from occupational exposure.

Dentists↗
PubMed1994

Characterization of somatostatin receptors on human neuroblastoma tumors.

Neuroblastoma is the most common extracranial solid tumor of children. Neuroblastoma tumors derive from the neural crest and synthesize neurotransmitters including the neuropeptide somatostatin. This study was designed to characterize somatostatin receptors both in primary neuroblastoma tumors and in two neuroblastoma cell lines, SKNSH and IMR32. Somatostatin receptors were identified in 6 of 7 Stage I and II compared to 7 of 19 Stage III and IV tumors. Down-regulation of somatostatin receptor binding was observed in five tumors during disease progression. A lack of high affinity binding of somatostatin was identified as a poor prognostic indicator; negative binding correlated with advanced disease and death. Somatostatin receptor binding was observed in the IMR32 cell line, but not in the SKNSH cell line. IMR32 cells demonstrated a single class of high affinity binding sites for both somatostatin and a synthetic analogue, octreotide (Kd 0.16 +/- 0.05 nM and 0.89 +/- 0.23 nM, respectively). Somatostatin and octreotide inhibited both vasoactive intestinal peptide-mediated and forskolin-mediated cyclic AMP accumulation in IMR32 cells. Somatostatin and octreotide inhibition of signal transduction was attenuated by pretreatment of the cells with pertussis toxin. Octreotide inhibited proliferation of IMR32 cells by 70% in a 6-day culture. In contrast, octreotide did not exhibit high affinity binding in SKNSH cells and had no effect on cyclic AMP accumulation or on proliferation in SKNSH cells. Together, these data indicate that octreotide interacts with high affinity somatostatin receptors to modulate signal transduction and regulate proliferation in neuroblastoma cell lines. These data also suggest that somatostatin receptor expression may be an independent prognostic factor in primary neuroblastoma tumors.

Binding, Competitive↗
PubMed1993

Non-competitive antagonism of calcium by magnesium ions at the K(+)-depolarised mouse neuromuscular junction.

The effect of raising the external Ca2+ concentration on miniature end-plate potential (m.e.p.p.) frequency was measured in the K(+)-depolarised mouse phrenic nerve/hemidiaphragm preparation in the presence of a range of Mg2+ concentrations. With increasing external Mg2+, a plot of external Ca2+ concentration vs. m.e.p.p. frequency was shifted to the right and the maximum frequency attained was reduced. A Schild plot of the data gave a slope factor close to two. These data suggest a non-competitive antagonism of Ca2+ by Mg2+ under these conditions.

Animals↗
PubMed1993

Cross-linking of presynaptic calcium channels: a mechanism of action for Lambert-Eaton myasthenic syndrome antibodies at the mouse neuromuscular junction.

Lambert-Eaton myasthenic syndrome (LEMS) is an autoimmune disorder of neuromuscular transmission. Immunoglobulin G (IgG) autoantibodies act presynaptically to cause functional loss of Ca2+ channels by down-regulation. This in turn causes reduced release of acetylcholine in response to nerve stimulation (i.e. reduced quantal content). We show here that in vitro application of LEMS IgG for 24 h was as effective in causing reduced quantal content in mice as injecting animals with the antibody for 2 days. Furthermore, incubation with divalent (F(ab')2) fragments also significantly reduced quantal content. However, monovalent (Fab) fragments were without significant effect. No antibody or antibody fragment preparation affected spontaneous release. Whole LEMS IgG and F(ab')2 (but not Fab) fragments also inhibited K(+)-evoked 45Ca2+ flux in a small cell carcinoma cell line. These findings present functional evidence that LEMS IgG-induced down-regulation of nerve terminal Ca2+ channels arises due to antibody cross-linking of these channels.

Acetylcholine↗
PubMed1993

Current classifications of HIV-associated periodontal diseases.

The occurrence of unusual and severe forms of periodontal disease in HIV-infected individuals is well recognised. Several classification schemes have been proposed in an effort to associate periodontal deterioration with progressive stages of HIV infection and to determine aetiological factors in tissue destruction. No classification to date has proved entirely satisfactory. This paper reviews current classification schemes and suggests an alternative based upon the periodontal status of a cohort of HIV seropositive patients in Edinburgh. The proposed classification includes 'conventional', non-specific gingivitis and adult periodontitis such as occur in HIV seronegative individuals, but which may also be seen in seropositive subjects. However, conditions termed linear gingivitis and necrotising periodontitis may be pathognomonic for HIV infection. It is recommended that the term 'HIV-associated' be dropped in relation to periodontal disease.

Gingivitis↗
PubMed1993

Comparative trial of fluconazole and amphotericin in the treatment of denture stomatitis.

The efficacy of fluconazole and amphotericin in the management of denture stomatitis was investigated in a comparative trial. Patients were assessed clinically, hematologically, and mycologically at the time of entry into the study and at 1, 4, and 12 weeks thereafter. A total of 29 patients were selected at random to receive 50 mg of fluconazole daily for 14 days; 30 patients were selected to receive amphotericin lozenges and cream for 28 days. Clinical response rates were similar in both treatment groups throughout the study. The best mycologic response was noted after 1 week whereas the best clinical response was observed after 4 weeks. Clinical evidence of relapse and recurrence at 12 weeks was a common finding irrespective of treatment. Side effects were uncommon in both groups.

Adult↗
PubMed1993

The prevalence of oral candidiasis in HIV-infected individuals and dental attenders in Edinburgh.

This study prospectively assessed the prevalence of oral candidal carriage and oral candidiasis in known HIV-seropositive individuals (n = 121) and other dental attenders in Edinburgh (n = 614). Candida species were isolated from 57.4% of dental attenders and 93.4% of HIV-seropositive subjects. Clinical evidence of oral candidiasis was observed in 6% and 52% of these groups respectively, erythematous forms of candidiasis being the commonest in both groups.

AIDS-Related Opportunistic Infections↗
PubMed1993

Immunohistochemical study of oral keratoses including lichen planus.

Biopsies of non-ulcerated oral mucosa from 13 patients with oral lichen planus and 12 patients with leukoplakia were immunohistochemically stained using monoclonal antibodies to pan T, pan B, T helper and T suppressor/cytotoxic cells and the stained lymphocytes enumerated using an image analyser. The results show the preponderance of T cells infiltrating both oral lichen planus and leukoplakia. The T helper: T suppressor/cytotoxic cell ratio was the same (1:2) for both oral lichen planus and leukoplakia. A similar proportion of T suppressor/cytotoxic cells was found infiltrating the epithelium. These data indicate that T cell subset analysis is of no value in distinguishing oral lichen planus from other oral keratoses.

Antibodies, Monoclonal↗
PubMed1993

Detection of Epstein-Barr virus and human papillomavirus type 16 DNA in hairy leukoplakia by in situ hybridisation and the polymerase chain reaction.

Demonstration of Epstein-Barr virus (EBV) is considered desirable for the accurate diagnosis of hairy leukoplakia (HL). Previous studies have reported possible associations with human papillomavirus (HPV) infection although this is not a universal finding. Presence of EBV and HPV 16 was examined in biopsy specimens from 18 cases of HL and ten control specimens by in situ hybridisation using digoxigenin-labelled synthetic oligonucleotide probes and by the polymerase chain reaction (PCR). The presence of EBV was demonstrated in 12 cases by both techniques. Of the remaining six cases EBV could be detected in three by in situ hybridisation but not by PCR; EBV was not detected by either method in a further three cases. All samples were negative for HPV 16 by both techniques under conditions of high stringency, although when stringency of in situ hybridisation was reduced, four samples appeared to harbour HPV DNA sequences. This study provides further evidence to support the role of EBV in the pathogenesis of HL and suggests that HPV 16 is not regularly encountered.

DNA Probes↗
PubMed1992

Multifocal hairy leukoplakia associated with Kaposi's sarcoma.

An HIV-seropositive patient presented with multifocal lesions of both hairy leukoplakia and Kaposi's sarcoma, hairy leukoplakia being present in the epithelium covering the Kaposi's sarcoma lesions. The findings suggest that hairy leukoplakia in immunocompromised patients is both more common and more widely distributed than is generally recognised.

Adult↗
PubMed1992

Periodontal bone loss in mice induced by different periodontopathic organisms.

Periodontal bone loss in mice orally inoculated with Peptostreptococcus anaerobius, Pept. magnus and Actinobacillus actinomycetemcomitans was compared to that in sham-inoculated mice. Six-to-8-week-old BALB/c mice were inoculated with 1 x 10(5), 1 x 10(7) or 1 x 10(9) colony-forming units (c.f.u.) of bacteria in 50 microliters of medium. Ten mice received each concentration of bacteria and 10 sham-inoculated mice acted as controls. Five mice from each of the groups were killed 6 weeks after inoculation and the remaining five mice at 12 weeks. Right hemimandibles were defleshed, stained and bone loss was measured using an image analyser. All the organisms tested were associated with bone loss. Animals that had received Pept. anaerobius and Pept. magnus had up to 18% more bone loss than those sham inoculated. In contrast, mice inoculated with A. actinomycetemcomitans had up to 38% more bone loss than the sham-inoculated animals, this amount of loss occurring at the lowest inoculation of 1 x 10(5) c.f.u. These data demonstrate a differential ability of micro-organisms to cause periodontal bone loss in mice.

Actinobacillus Infections↗
PubMed1992

Hairy leukoplakia in an HIV-negative, nonimmunosuppressed patient.

Oral hairy leukoplakia is an Epstein-Barr virus-associated lesion that is considered to be a marker of immunosuppression. We report a case of oral hairy leukoplakia in a healthy nonimmunosuppressed elderly patient with no evidence of HIV infection on repeated investigation. This report has important implications on our understanding of the significance of this lesion.

Aged↗
PubMed1992

Ingestion of medication among patients with oral keratoses including lichen planus.

One hundred forty-nine patients attending Edinburgh Dental Hospital had oral keratosis diagnosed clinically and histologically. The keratoses were grouped into erosive and nonerosive lichen planus, other keratoses infiltrated with inflammatory cells, and noninfiltrated keratoses. Drug histories were obtained from each patient on presentation, and the groups were analyzed to assess the association between the ingestion of commonly prescribed drugs and oral keratoses. Patients with infiltrated keratoses took nonsteroidal anti-inflammatory drugs twice as often as patients in the other groups, whereas those with lichen planus more frequently ingested antihypertensive drugs. Patients with erosive lichen planus were 10 times more likely to ingest nonsteroidal anti-inflammatory drugs than those with nonerosive lichen planus (p = 0.01).

Administration, Oral↗
PubMed1991

Oro-antral fistula: an unusual complication of HIV-associated periodontal disease.

Oral lesions have been reported frequently in patients seropositive for human immunodeficiency virus. A case is reported of HIV-associated periodontitis complicated by necrotising stomatitis and the development of an oro-antral fistula; the role of extractions in the management of this condition is highlighted.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Hairy leukoplakia--a histological study.

Hairy leukoplakia is a recently described oral mucosal condition seen in immunosuppressed individuals, usually in association with HIV infection, when it is thought to be a sign of decreasing immunocompetence. It probably results from reactivation of infection by Epstein-Barr virus (EBV) and usually presents as bilateral white patches on the lateral borders of the tongue. From a histological study of 20 cases we have found that the typical appearance of hairy leukoplakia is of acanthotic, hyperparakeratinized epithelium with Candida hyphae sometimes present in the parakeratin. A band of EBV infected, koilocyte-like cells is present in the upper part of the prickle cell layers, these cells being swollen and pale staining, with prominent cell borders and perinuclear vacuoles. There is a paucity of inflammation in both the epithelium and lamina propria. An atypical appearance shows the koilocyte-like cells lying isolated or in small groups, irregularly arranged in the prickle cell layer and without a hyperparakeratinized surface. Diagnosis of hairy leukoplakia should normally be confirmed by demonstrating EBV in the koilocyte-like cells by immunocytochemistry or DNA in situ hybridization.

Candida↗