Biomedical subjects

S Cameron

Publications and source records attributed to S Cameron.

At least 19 recordsLinked to original sources

PubMed2006

Does using potting mix make you sick? Results from a Legionella longbeachae case-control study in South Australia.

A case-control study was performed in South Australia to determine if L. longbeachae infection was associated with recent handling of commercial potting mix and to examine possible modes of transmission. Twenty-five laboratory-confirmed cases and 75 matched controls were enrolled between April 1997 and March 1999. Information on underlying illness, smoking, gardening exposures and behaviours was obtained by telephone interviews. Recent use of potting mix was associated with illness (OR 4.74, 95% CI 1.65-13.55, P=0.004) in bivariate analysis only. Better predictors of illness in multivariate analysis included poor hand-washing practices after gardening, long-term smoking and being near dripping hanging flower pots. Awareness of a possible health risk with potting mix protected against illness. Results are consistent with inhalation and ingestion as possible modes of transmission. Exposure to aerosolized organisms and poor gardening hygiene may be important predisposing factors to L. longbeachae infection.

Adult↗

PubMed2006

Hospital transmission of hepatitis B virus in the absence of exposure prone procedures.

In February and in June 1998, two people developed acute hepatitis B following in-patient care in a district general hospital. Initial enquiries indicated their infections were not attributable to staff undertaking exposure-prone procedures (EPPs). We report the findings and implications of the subsequent investigation: a multi-disciplinary, multi-agency investigation, including molecular epidemiological analysis. Occupational Health records showed that staff involved in EPPs with the patients were HBsAg negative. No contact between the patients was identified nor were there failures in sterilization. The patients' HBV strains were identical, indicating a common source. A total of 231 out of 232 staff who might have treated either patient were tested for HBsAg; the remaining doctor, working abroad, was HBsAg- and HBeAg-positive and had the same HBV strain as the patients. On two occasions the doctor's hand had been cut while breaking glass vials, but there was no documentation linking these events to the two patients. The doctor had been vaccinated in 1993 and tested for anti-HBs prior to commencing work in 1997. The doctor was recalled to Occupational Health but did not attend and was not followed up. In total, 4948 patients potentially treated by the doctor received an explanatory letter and 3150 were tested for HBsAg. Only one was positive, and HBV sequencing showed no link to the doctor. Occasionally transmission of HBV from heath-care workers can occur in a non-EPP setting and the implications of this require examination by those setting national policy. Occupational Health Services should investigate clinical heath-care workers who do not respond to vaccination. They should ensure HBV carriers are identified and offer them appropriate advice to prevent transmission to patients.

Adult↗

PubMed2006

Extraordinary number of gene rearrangements in the mitochondrial genomes of lice (Phthiraptera: Insecta).

The arrangement of genes in the mitochondrial (mt) genomes of most insects is the same, or near-identical, to that inferred to be ancestral for insects. We sequenced the entire mt genome of the small pigeon louse, Campanulotes bidentatus compar, and part of the mt genomes of nine other species of lice. These species were from six families and the three main suborders of the order Phthiraptera. There was no variation in gene arrangement among species within a family but there was much variation in gene arrangement among the three suborders of lice. There has been an extraordinary number of gene rearrangements in the mitochondrial genomes of lice!

Animals↗

PubMed2005

An evaluation of the impact of a national health demonstration project on testing and management for Chlamydia trachomatis infections in two regions of Scotland.

OBJECTIVES: To compare clinical practice relating to testing for, and management of, genital Chlamydia trachomatis infection in the Lothian and Grampian regions of Scotland as part of an evaluation of a Government-funded health demonstration project in Lothian, Healthy Respect. STUDY DESIGN: Clinical audit against standards developed from a national clinical guideline. METHODS: Clinical practice relating to testing for, and management of, genital C. trachomatis infection was assessed against standards for good quality care developed from a national clinical guideline (Scottish Intercollegiate Guidelines Network Guideline 42). Audit methods comprised: postal survey of primary care clinicians; review of referral letters from primary to secondary care; and review of primary and secondary care patient case records. Findings from Lothian and Grampian were compared. RESULTS: Questionnaires were returned by 167 primary care clinicians in Lothian and 96 in Grampian. Clinicians in Lothian and Grampian gave similar responses relating to: testing of symptomatic patients (87 vs 88%); offer of testing for asymptomatic young patients (55 vs 55%); choice of antichlamydial agent (47 vs 42% azithromycin as first line); and follow-up strategies (50 vs 51% offer follow-up in primary care). Clinicians in Lothian were significantly more likely to participate in partner notification work (57 vs 44%; P=0.04) and to agree with statements reflecting 'perceived self-efficacy' in chlamydia-related care (57 vs 48%; P=0.006). Referral letters from primary to secondary care were reviewed for 31 women with genital symptoms in Lothian and 28 in Grampian. More women in Lothian were tested for chlamydia prior to referral (65 vs 39%; difference not significant). Review of primary care records for consultations in young people (145 in Lothian; 203 in Grampian) showed a higher level of chlamydia testing in Grampian (Lothian, 14%; Grampian, 34%; P<0.0001). However, review of secondary care records (n=39) showed a much higher level of testing in Lothian (Lothian, 75%; Grampian, 9%; P<0.0001). Review of secondary care records relating to proven chlamydia-positive women (n=159) suggested better care in Lothian in relation to ensuring antibiotic treatment (Lothian, 91%; Grampian, 74%; P=0.004), and use of the preferred antibiotic, azithromycin (Lothian, 78%; Grampian, 37%; P<0.0001). However, documented referral to a health adviser appeared to be better in Grampian (Lothian, 32%; Grampian, 48%; P=0.048). CONCLUSIONS: During the period of activity of the Healthy Respect demonstration project, few differences were detected between clinicians in Lothian and Grampian with regard to chlamydia-related practice. In both regions, clinicians appeared to be very aware of the need to test for chlamydia in patients with relevant symptoms, but were less likely to offer opportunistic testing to young patients without specific symptoms. These findings suggest that Healthy Respect in Lothian has had little impact on clinicians. However, these findings must be considered within the context of a broader evaluation, and it is noteworthy that the few significant differences that were detected tended to suggest better practice in Lothian.

Chlamydia Infections↗

PubMed2005

Gain-swept superradiance applied to the stand-off detection of trace impurities in the atmosphere.

We show that gain-swept superradiance can be used to detect low (parts per million) concentrations of various gases at distances on the order of kilometers, which is done by using pulse timing to create small regions of gain at positions that sweep toward a detector. The technique is far more sensitive than previous methods such as light detection and ranging or differential absorption light detection and ranging.

Journal Article↗

PubMed2005

A randomized, double-blind, placebo-controlled trial of CDP571, a humanized monoclonal antibody to tumour necrosis factor-alpha, in patients with corticosteroid-dependent Crohn's disease.

AIM: To evaluate CDP571, a humanized monoclonal antibody to tumour necrosis factor-alpha, for the treatment of corticosteroid-dependent Crohn's disease. METHODS: Patients with corticosteroid-dependent Crohn's disease (use of prednisolone 15-40 mg/day or budesonide 9 mg/day for at least 8 weeks, a previous failed attempt to discontinue corticosteroids within 8 weeks, and Crohn's Disease Activity Index score 150 points or less) were enrolled in a 16-week, randomized, double-blind, placebo-controlled trial. The patients received intravenous CDP571 (20 mg/kg at week 0 and 10 mg/kg at week 8) or placebo. Corticosteroid therapy was decreased following a predefined schedule. The primary efficacy end-point was the percentage of patients with corticosteroid-sparing [i.e. no disease flare (Crohn's Disease Activity Index score > or =220 points) and no longer requiring corticosteroid therapy] at week 10. The major secondary efficacy end-point was corticosteroid-sparing at week 16. RESULTS: Seventy-one patients received treatment. Corticosteroid-sparing was achieved by 19 of 39 (48.7%) CDP571 patients and 13 of 42 (40.6%) placebo patients (P = 0.452) at week 10, and by 18 of 39 (46.2%) CDP571 patients and seven of 32 (21.9%) placebo patients (P = 0.032) at week 16. CDP571 therapy was well-tolerated and the incidence of serious adverse events was similar to placebo. CONCLUSIONS: The CDP571 was effective for corticosteroid-sparing at week 16 but not week 10, and was well-tolerated in patients with corticosteroid-dependent Crohn's disease.

Adult↗

PubMed2005

Prevalence of, and risk factors for, hepatitis C virus infection among recent initiates to injecting in London and Glasgow: cross sectional analysis.

Our aim was to compare the prevalence of antibody to hepatitis C virus (anti-HCV) among recently initiated injecting drug users (IDUs) in London and Glasgow, and to identify risk factors which could explain differences in prevalence between the cities. Complementary studies of community recruited IDUs who had initiated injection drug use since 1996 were conducted during 2001-2002. Data on HCV risk behaviours were gathered using structured questionnaires with identical core questions and respondents were asked to provide an oral fluid specimen which was tested anonymously for anti-HCV but was linked to the questionnaire. Sensitivities of the anti-HCV assays for oral fluid were 92-96%. Prevalence of anti-HCV was 35% (122/354) in London and 57% (207/366) in Glasgow (P < 0.001). Multifactorially, factors significantly associated with raised odds of anti-HCV positivity were increasing length of injecting career, daily injection, polydrug use, having had a needlestick injury, and having served a prison sentence. In addition lower odds of anti-HCV positivity were associated with non-injection use of crack cocaine and recruitment from drug agencies. After adjustment for these factors, the increased odds of anti-HCV associated with being a Glasgow IDU were diminished but remained significant. HCV continues to be transmitted among the IDU population of both cities at high rates despite the availability of syringe exchange and methadone maintenance. Effectiveness of harm reduction interventions may be compromised by inadequate coverage and failure to reduce sufficiently the frequency of sharing different types of injecting equipment, as well as the high background prevalence of HCV, and its high infectivity. Comprehensive action is urgently required to reduce the incidence of HCV among injectors.

Adult↗

PubMed2005

Are humans infected by Hantaviruses in Australia?

Hantavirus antibody-positive rodents have been found across Australia although, to date, there are no reports of infections in humans. This could be due to misdiagnosis clinically and/or inadequate laboratory technique/skills. There are close trading ties between Australia and Asian countries as well as our geographical neighbours where both human and rodent infections are found, so importation is a continuing threat. We consider that further sero-epidemiological surveys are warranted among rodents (especially those captured from ports in Australia), in patients from renal and respiratory wards of hospitals, and in residents and employees close to harbours using more specific and sensitive laboratory techniques than have been available in the past.

Australia↗

PubMed2004

Incidence of hepatitis C virus infection and associated risk factors among Scottish prison inmates: a cohort study.

To gauge the incidence of hepatitis C virus (HCV) infection and associated risk factors among inmates during their imprisonment, the authors recruited adult males in a long-stay Scottish prison into a cohort study between April 1999 and October 2000. On two occasions (at 0 and 6 months), saliva was collected for anonymous HCV antibody testing and risk behavior data were obtained through a self-administered questionnaire. The participation rate was 85% at both initial recruitment (612/719) and follow-up (375/441; 171 men were ineligible for follow-up). For inmates who reported never having injected drugs, ever having injected drugs, having injected drugs during follow-up, and having shared needles/syringes during follow-up, HCV incidences per 100 person-years of incarceration risk were 1, 12, 19, and 27, respectively. Ever having injected drugs (relative risk = 13.0, 95% confidence interval: 1.5, 114.3) and having shared needles/syringes during follow-up (relative risk = 9.0, 95% confidence interval: 1.1, 71.7) were significantly associated with HCV seroconversion. The effectiveness of existing interventions, including the provision of bleach tablets for sterilizing injection equipment, was suboptimal. The development of methadone maintenance programs in prisons and the creation of drug courts to keep offending drug injectors out of prison might help to reduce transmission in this setting.

Adult↗

PubMed2003

Hepatitis C infection among dental personnel in the West of Scotland, UK.

Hepatitis C virus (HCV) is considered a serious occupational hazard for healthcare workers, particularly those performing exposure-prone procedures. In the UK, the majority of dental procedures are classified as exposure prone. In order to gauge the prevalence and determinants of infection among dental healthcare workers, a voluntary anonymous survey of HCV infection among primary care dental workers employed in the West of Scotland was undertaken, in which occupational and personal risk data were collected in parallel with a blood specimen. The overall prevalence of HCV antibodies was 0.1% (1/880, 95% CI 0-0.6); this is no greater than the estimated prevalence of HCV infection in the local population. Personal risk data collected suggested that the single infection identified was acquired through a non-occupational route. These results suggest that HCV infection is not a major occupational risk for dental healthcare workers.

Dental Auxiliaries↗

PubMed2003

Randomized controlled trial of brief cognitive behaviour therapy versus treatment as usual in recurrent deliberate self-harm: the POPMACT study.

BACKGROUND: We carried out a large randomized trial of a brief form of cognitive therapy, manual-assisted cognitive behaviour therapy (MACT) versus treatment as usual (TAU) for deliberate self-harm. METHOD: Patients presenting with recurrent deliberate self-harm in five centres were randomized to either MACT or (TAU) and followed up over 1 year. MACT patients received a booklet based on cognitive behaviour therapy (CBT) principles and were offered up to five plus two booster sessions of CBT from a therapist in the first 3 months of the study. Ratings of parasuicide risk, anxiety, depression, social functioning and global function, positive and negative thinking, and quality of life were measured at baseline and after 6 and 12 months. RESULTS: Four hundred and eighty patients were randomized. Sixty per cent of the MACT group had both the booklet and CBT sessions. There were seven suicides, five in the TAU group. The main outcome measure, the proportion of those repeating deliberate self-harm in the 12 months of the study, showed no significant difference between those treated with MACT (39%) and treatment as usual (46%) (OR 0.78, 95% CI 0.53 to 1.14, P=0.20). CONCLUSION: Brief cognitive behaviour therapy is of limited efficacy in reducing self-harm repetition, but the findings taken in conjunctin with the economic evaluation (Byford et al. 2003) indicate superiority of MACT over TAU in terms of cost and effectiveness combined.

Adult↗

PubMed2003

Expression of inducible nitric oxide synthase in cutaneous adnexal tumours of the head and neck.

Adnexal tumours are a rare heterogeneous group of neoplasms, most commonly found in the head and neck region. Although most are benign, malignant adnexal tumours often behave aggressively, resulting in early metastasis. There is increasing interest in the role that nitric oxide (NO) plays in the behaviour of many cancers. It is thought that NO, produced by the enzyme inducible NO synthase (iNOS), facilitates tumour growth and dissemination. iNOS has been studied in the common skin cancers, where its expression correlates with tumour behaviour, but it has not been previously investigated in cutaneous adnexal tumours. An immunhistochemical study was performed using a monoclonal antibody to iNOS in 37 cases of adnexal tumours (19 benign, 18 malignant). iNOS expression was weakly expressed by basal keratinocytes of adjacent skin in all cases and it was variably expressed in the tumours. Malignant tumours had significantly increased iNOS expression when compared to both adjacent skin (P<0.001) and the benign tumour group (P<0.001). No significant difference was found between iNOS expression in benign tumour and adjacent skin (P=0.5). The role of iNOS in this rare group of tumours and the possibility of pharmacologically inhibiting it in the clinical setting warrants further investigation.

Adenocarcinoma, Sebaceous↗

PubMed2002

Prevalence of hepatitis C among injectors in Scotland 1989-2000: declining trends among young injectors halt in the late 1990s.

We previously reported a continual decline in anti-HCV prevalence among young injectors from Glasgow and Lothian between 1990 and 1997. The original study was extended to ascertain if the anti-HCV prevalence among injectors from Glasgow, Lothian, Tayside and Grampian had changed since 1997. Residual sera from injectors who had undergone attributable anti-HIV testing were tested anonymously for anti-HCV. In all four regions, no significant changes in prevalence were found among those aged < 25 years during the late 1990s (Glasgow 1997-9/00: 43%-41%; Lothian 1997-9: 13%-17%; Tayside 1997-9: 45%-35%; Grampian 1996-9: 28%-29%). Among those aged > or = 25 years, significant decreases in prevalence were only observed in Glasgow (1997-9/00: 79%-72%, P = 0.03) and Lothian (1997-9: 54%-45%, P = 0.05). The findings highlight that existing harm reduction measures, acknowledged as having helped to reduce the spread of HCV, are not sufficient to bring this epidemic under control and reduce transmission to sporadic levels.

Adolescent↗

PubMed2002

Improving cycle control in progestogen-only contraceptive pill users by intermittent treatment with a new anti-progestogen.

BACKGROUND: The safety and efficacy of the anti-progestogen Org 31710 in improving cycle control in healthy women using the desogestrel progestogen-only pill was investigated in this randomized, double-blind, placebo-controlled study. METHODS: A total of 103 women using the 75 micro g desogestrel progestogen-only pill daily also received either 150 mg Org 31710 or placebo once every 28 days, starting on day 1, for a duration of 4-7 treatment cycles. RESULTS: The percentage of women with bleeding or spotting (B/S) every day in the placebo group was on average 30% during the whole treatment period and no days without reported B/S occurred. In contrast, a cyclic pattern was observed for the Org 31710 group; a peak incidence of B/S was observed on day 3 or 4 of each cycle, followed by a sharp decrease on cycle days 9-15. Compared with controls, less subjects in the Org 31710 group reported irregular, frequent or prolonged bleeding. These differences were clearly observed in the initial cycles, but were somewhat less pronounced during the later cycles of the treatment period. A relatively high incidence of B/S episodes starting in the second section of the cycle was also observed. CONCLUSION: The addition of Org 31710 once a month improved cycle control in women using daily treatment with 75 micro g desogestrel.

Adolescent↗

PubMed2001

Phagocytosis promotes programmed cell death in C. elegans.

In the nematode Caenorhabditis elegans programmed cell death requires the killer genes egl-1, ced-4 and ced-3 (refs 1 and 2), and the engulfment of dying cells requires the genes ced-1, ced-2, ced-5, ced-6, ced-7, ced-10 and ced-12 (refs 3,4,5). Here we show that engulfment promotes programmed cell death. Mutations that cause partial loss of function of killer genes allow the survival of some cells that are programmed to die, and mutations in engulfment genes enhance the frequency of this cell survival. Furthermore, mutations in engulfment genes alone allow the survival and differentiation of some cells that would normally die. Engulfment genes probably act in engulfing cells to promote death, as the expression in engulfing cells of ced-1, which encodes a receptor that recognizes cell corpses, rescues the cell-killing defects of ced-1 mutants. We propose that engulfing cells act to ensure that cells triggered to undergo programmed cell death by the CED-3 caspase die rather than recover after the initial stages of death.

Animals↗

PubMed2001

Suppressors of cytokine signaling-1 and -6 associate with and inhibit the insulin receptor. A potential mechanism for cytokine-mediated insulin resistance.

Insulin resistance contributes to a number of metabolic disorders, including type II diabetes, hypertension, and atherosclerosis. Cytokines, such as tumor necrosis factor-alpha, interleukin-1 beta, and interleukin-6, and hormones, such as growth hormone, are known to cause insulin resistance, but the mechanisms by which they inhibit the cellular response to insulin have not been elucidated. One mechanism by which these agents could cause insulin resistance is by inducing the expression of cellular proteins that inhibit insulin receptor (IR) signaling. Suppressors of cytokine signaling (SOCS) proteins are negative regulators of cytokine signaling pathways, the expression of which is regulated by certain cytokines. SOCS proteins are therefore attractive candidates as mediators of cytokine-induced insulin resistance. We have found that SOCS-1 and SOCS-6 interact with the IR when expressed in human hepatoma cells (HepG2) or in rat hepatoma cells overexpressing the human IR. In SOCS-1-expressing cells, insulin treatment increases the extent of interaction with the IR, whereas in SOCS-6-expressing cells the association with the IR appears to require insulin treatment. SOCS-1 and SOCS-6 do not inhibit insulin-dependent IR autophosphorylation, but both proteins inhibit insulin-dependent activation of ERK1/2 and protein kinase B in vivo and IR-directed phosphorylation of IRS-1 in vitro. These results suggest that SOCS proteins may be inhibitors of IR signaling and could mediate cytokine-induced insulin resistance and contribute to the pathogenesis of type II diabetes.

Cell Line↗

PubMed2001

An efficacious recombinant subunit vaccine against the salmonid rickettsial pathogen Piscirickettsia salmonis.

Piscirickettsia salmonis is the aetiological agent of salmonid rickettsial septicaemia, an economically devastating rickettsial disease of farmed salmonids. Infected salmonids respond poorly to antibiotic treatment and no effective vaccine is available for the control of P. salmonis. Bacterin preparations of P. salmonis were found to elicit a dose-dependent response in coho salmon (Oncorhynchus kisutch), which varied from inadequate protection to exacerbation of the disease. However, an outer surface lipoprotein of P. salmonis, OspA, recombinantly produced in Escherichia coli elicited a high level of protection in vaccinated coho salmon with a relative percent survival as high as 59% for this single antigen. In an effort to further improve the efficacy of the OspA recombinant vaccine, T cell epitopes (TCE's) from tetanus toxin and measles virus fusion protein, that are universally immunogenic in mammalian immune systems, were incorporated tandemly into an OspA fusion protein. Addition of these TCE's dramatically enhanced the efficacy of the OspA vaccine, reflected by a three-fold increase in vaccine efficacy. These results represent a highly effective monovalent recombinant subunit vaccine for a rickettsia-like pathogen, P. salmonis, and for the first time demonstrate the immunostimulatory effect of mammalian TCE's in the salmonid immune model. These results may also be particularly pertinent to salmonid aquaculture in which the various subspecies are outbred and of heterologous haplotypes.

Amino Acid Sequence↗

PubMed2001

Trends in HCV prevalence among injecting drug users in Glasgow and Edinburgh during the era of needle/syringe exchange.

In 1998, we reported that anti-HCV prevalence among injectors from Glasgow had declined between 1990 and 1995. We set out to ascertain if the anti-HCV prevalence among injectors from Edinburgh had declined similarly during this period and if there had been any trend in prevalence among injectors from both cities since 1995. Residual sera from both cities' injecting drug users who had undergone named HIV testing were identified, linked to age band and gender information and tested anonymously for anti-HCV. Among Edinburgh's injectors, significant (p < 0.0001) decreases in anti-HCV prevalence from 69% (1989/90) to 13% (1997) and from 80% (1989/90) to 54% (1997) were seen in those aged < 25 y and > or = 25 y, respectively. Among Glasgow's injectors, a significant (p < 0.0001) decrease in prevalence from 91% (1990) to 43% (1997) was seen only among those aged < 25 y. Of both cities' 15-19 y olds, sampled during 1995-97, 17% (24/139) were anti-HCV-positive. The findings suggest that the incidence of HCV among young injectors continued to decrease during the 1990s--the era of needle/syringe exchange and other interventions--but is still too high. Further investigative and preventive work is required.

Adult↗