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C Graham

Publications and source records attributed to C Graham.

At least 55 records · Page 3Linked to original sources
PubMed2001

Test of HIV incidence shows continuing HIV transmission in homosexual/bisexual men in England and Wales.

It has been suggested that HIV incidence will decrease with the increased use of antiretroviral Therapy (ART) in HIV infected homosexual/bisexual men. HIV incidence was measured using a sensitive/less sensitive assay technique, at a time when combination ART was widespread. The Serological Testing Algorithm for Recent HIV Seroconversion (STARHS)13 technique was applied to syphilis test specimens collected from homosexual/bisexual men attending 15 sexually transmitted infections (STI) clinics which participated in an unlinked anonymous serosurvey of HIV infection during 1998. The HIV incidence rate was adjusted to compensate for patients who had a repeat syphilis test within the same year. Leftover syphilis test sera from 6202 men had been unlinked and anonymised, of which 415 were HIV positive. Sera from 412 (99.3%) patients were available. The STARHS assay showed 62 to have been recently infected with HIV (approximately in the last four months), giving an incidence of 3.33% per annum (95% CI: 2.06%-5.27%). The highest incidence was seen in those aged 35-44 years. About 46% of all HIV-infected homosexual/bisexual men were probably receiving combination ART at this time. If 10% of those on treatment were misclassified as recent infections the incidence would have been 2.58% per annum (95% CI: 1.53%-4.24%). In homosexual/bisexual men having syphilis tests at STI clinics in the UK during 1998 the incidence of HIV infection was between two and three per hundred per year. Treatment with combination ART of almost a half of homosexual/bisexual men who are HIV infected in the population is compatible with appreciable continuing HIV transmission among those at high behavioural risk. Public health surveillance systems for those at high risk for HIV infection should, as soon as possible, incorporate the STARHS methodology for monitoring recent HIV incidence.

Adult↗
PubMed2001

PHLS overview of communicable diseases 1999.

Every other year since 1995 the Public Health Laboratory Service has undertaken a consultation exercise to identify communicable diseases of high public health priority. The purpose of identifying disease priorities is to guide rational and transparent service planning and resource allocation. Also, the process aims to ensure a customer sensitive service. This paper presents the results of the priority setting exercise undertaken in 1999. A postal questionnaire was sent to 1130 key professionals involved in communicable disease control in the United Kingdom. Respondents were asked to assess the relative priority of 61 communicable diseases and to identify priority areas of work associated with these diseases. Five criteria were used to assess relative priority. The five criteria were; present burden of ill-health, social and economic impact, potential threat to health, health gain opportunity and public concern and confidence. For each disease, respondents were asked to score the importance of each criterion. Forty six percent of participants (518/1130) returned completed questionnaires. There was no significant difference in response rate by professional group. Based on the scores assigned to each of the five criteria, the relative priority of 61 communicable diseases has been established. The top ten diseases in descending order of priority are, HIV/AIDS, meningococcal diseases, Chlamydia trachomatis, influenza, tuberculosis, E. coli O157, Methicillin resistant Staphylococcus aureus, salmonellosis, transmissible spongiform encephalopathies and Helicobacter pylori. The opinion of a large number of health care professionals has been used to establish a priority rank for a wide range of communicable diseases. This work provides planners and policy makers with a synthesis of current professional opinion that can be used as a foundation for making decisions on service developments.

Attitude of Health Personnel↗
PubMed2001

Side effects of low-dose pyridostigmine bromide are not related to cholinesterase inhibition.

BACKGROUND: Pretreatment with pyridostigmine bromide (PB) has become part of standard military procedures for protection against the effects of possible chemical warfare attack. The purpose of the work reported here was to quantify the type, intensity and frequency of side effects of low-dose PB, and to examine factors that predict the intensity and frequency of side effects. METHOD: A double-blind, cross-over, placebo (PL)-controlled design was used. Of the 67 subjects, 33 received 30 mg PB every 8 h for 13 doses, and 34 received 60 mg on the same schedule. Order of PB and PL administration was counterbalanced. RESULTS: Overall, side effects were mild, even at the 60-mg dose level. More side effects were reported when volunteers were taking PB than when they were taking placebo. Women reported more symptoms than men. Neither cholinesterase inhibition nor plasma levels of PB predicted side effect scores during the PB week; the best predictor of side effect scores during the PB week was side effect scores during the PL week. CONCLUSION: PB is well tolerated by healthy young people, even when twice the recommended military dose is administered.

Adolescent↗
PubMed2000

What a test for recent infection might reveal about HIV incidence in England and Wales.

BACKGROUND: A laboratory method has been developed that detects recent HIV infection and allows incidence to be estimated by testing single stored antibody-positive specimens. A theoretical exploration of the method's surveillance utility was carried out. METHODS: Using various data sources, HIV incidence rates were postulated. The confidence intervals (CI) for these postulated incidences were calculated using the expected number of recent infections for each postulated incidence, the actual number tested for HIV, and the known number of HIV-1 positives. A test for trend was used to determine when an important change in incidence could be recognized. RESULTS: If the incidence was 5% per annum (p.a.) in homosexual/bisexual men attending sexually transmitted diseases (STD) clinics in London, 64 recent infections would be expected in the 392 HIV-seropositive specimens and, if observed, would result in a 95% CI of 3.1-7.9% p.a. for the incidence rate. An incidence of 1% p.a. in pregnant women would be most unlikely as this would require detection of 193 recent infections, 26 more than the total 167 HIV-seropositive specimens found in 1997. In African women attending STD clinics in London, 30% of prevalent infections would be classified as recent if the incidence was 5% p.a. Further, if the incidence in homosexual/bisexual men were to fall by 50% over 3 years, a decrease of this magnitude would be recognized as significant within 2 years. CONCLUSIONS: The detuned assay will increase the information from HIV serosurveys even where prevalence and incidence are relatively low. Existing surveillance systems should be redesigned to take full advantage of the method.

Confidentiality↗
PubMed2000

A 6-Mb high-resolution physical and transcription map encompassing the hereditary prostate cancer 1 (HPC1) region.

Several hereditary disease loci have been genetically mapped to the chromosome 1q24-q31 interval, including the hereditary prostate cancer 1 (HPC1) locus. Here, we report the construction of a 20-Mb yeast artificial chromosome contig and a high-resolution 6-Mb sequence-ready bacterial artificial chromosome (BAC)/P1-derived artificial chromosome (PAC) contig of 1q25 by sequence and computational analysis, STS content mapping, and chromosome walking. One hundred thirty-six new STSs, including 10 novel simple sequence repeat polymorphisms that are being used for genetic refinement of multiple disease loci, have been generated from this contig and are shown to map to the 1q25 interval. The integrity of the 6-Mb BAC/PAC contig has been confirmed by restriction fingerprinting, and this contig is being used as a template for human chromosome 1 genome sequencing. A transcription mapping effort has resulted in the precise localization of 18 known genes and 31 ESTs by database searching, exon trapping, direct cDNA hybridization, and sample sequencing of BACs from the 1q25 contig. An additional 11 known genes and ESTs have been placed within the larger 1q24-q31 interval. These transcription units represent candidate genes for multiple hereditary diseases, including HPC1.

Base Sequence↗
PubMed2000

Bacteraemia and antibiotic resistance of its pathogens reported in England and Wales between 1990 and 1998: trend analysis.

OBJECTIVES: Determination of causes, trends, and antibiotic resistance in reports of bacterial pathogens isolated from blood in England and Wales from 1990 to 1998. DESIGN: Description of bacterial isolates from blood, judged to be clinically significant by microbiology staff, reported to the Communicable Disease Surveillance Centre. SETTING: Microbiology laboratories in England and Wales. SUBJECTS: Patients yielding clinically significant isolates from blood. MAIN OUTCOME MEASURES: Frequency and Poisson regression analyses for trend of reported causes of bacteraemia and proportions of antibiotic resistant isolates. RESULTS: There was an upward trend in total numbers of reports of bacteraemia. The five most cited organisms accounted for over 60% of reports each year. There was a substantial increase in the proportion of reports of Staphylococcus aureus resistant to methicillin, Streptococcus pneumoniae resistance to penicillin and erythromycin, and Enterococcus faecalis and Enterococcus faecium resistance to vancomycin. No increase was seen in resistance of Escherichia coli to gentamicin. CONCLUSIONS: Reports from laboratories provide valuable information on trends and antibiotic resistance in bacteraemia and show a worrying increase in resistance to important antibiotics.

Bacteremia↗
PubMed2000

Hepatitis C.

In the latter half of the 20th century, HCV emerged as the most common cause of chronic liver disease, and will likely remain so. Since its initial discovery in 1989, rapid progress has been made in our understanding of the virology, epidemiology, natural history, diagnosis, and treatment of HCV. Over the next few decades, as further advancements are made, superior treatment options will become available.

Antiviral Agents↗
PubMed2000

Nocturnal magnetic field exposure: gender-specific effects on heart rate variability and sleep.

OBJECTIVE: To determine if controlled exposure to power-frequency magnetic fields alters heart rate variability (HRV) and polysomnographic endpoints in healthy men (n=22) and women (n=24), 40-60 years of age. METHODS: A randomized, double-blind, crossover design was used. Study endpoints collected during all-night exposure to 60 Hz magnetic fields at an occupational intensity (resultant flux density=28.3 microTesla, microT) were compared to similar endpoints obtained under equivalent, counterbalanced, no-exposure (< or =0.2 microT) control conditions. RESULTS: Older men, but not women, exposed to the magnetic fields showed power reductions in the LF band of the HRV frequency spectrum, which is associated with sympathetically-mediated blood pressure and thermoregulatory control (P<0.04). Older women, but not men, exposed to the fields showed a pattern of disrupted sleep, with reductions in the duration of REM sleep (P=0.03), and strong trends for reductions in sleep efficiency (P=0.06) and total sleep time (P=0.06). CONCLUSIONS: The gender-specific effects seen here with older volunteers replicate the results of previous exposure studies with younger men and women.

Adult↗
PubMed2000

Brain frequency magnetic fields alter cardiac autonomic control mechanisms.

OBJECTIVE: Heart rate variability (HRV) is a noninvasive indicator of sympathetic and vagal cardiovascular control known to be tightly correlated with sleep stages. Recent studies indicate that HRV in humans is altered by nocturnal exposure to power-frequency (60 Hz) magnetic fields. Given the central origin of autonomic cardiac control, we determined if field exposure in the beta(1) EEG/MEG frequency range was a more effective stimulus for HRV alteration than 60 Hz fields, and explored the mechanisms involved. METHODS: Healthy young men were exposed (n=9) overnight to an intermittent magnetic field (16 Hz, 28.3 microTesla, microT), or sham exposed (n=9), under blind test conditions in a laboratory exposure facility. RESULTS: Field exposure was associated (P<0.05) with reduced power in the low band of the HRV frequency spectrum, and with decreases in mean heart rate. Analysis of the timing of the R waves surrounding each on-off transition of the intermittent field revealed no evidence for a direct effect on the cardiac pacemaker. CONCLUSIONS: Magnetic field exposure in the EEG/MEG beta(1) frequency range alters HRV via a CNS effect. Phase-resetting experiments rule out a direct effect on the cardiac pacemaker. Biophysical calculations of the intensity of the electric fields induced in brain versus heart under the present exposure conditions are also consistent with and support a central rather than a peripheral site of action.

Adult↗
PubMed2000

Multi-night exposure to 60 Hz magnetic fields: effects on melatonin and its enzymatic metabolite.

Magnetic field-induced suppression of nocturnal melatonin in humans has been reported in occupational and residential studies, but not in laboratory-based exposure studies. The present study examined whether this contrasting pattern of results might be related to associated differences in exposure duration or to field-induced measurement instability over time. Thirty healthy young men were evaluated using a randomized, double-blind test protocol. Statistical analysis indicated that 4 consecutive nights of exposure to power-frequency magnetic fields at occupational intensity (resultant flux density = 28.3 microtesla, muT, [283 milligauss, mG]) had no differential effect on concentrations of melatonin or its major enzymatic metabolite (6-hydroxymelatonin sulfate, 6-OHMS) in daily morning urine samples, compared to equivalent no-exposure sham control conditions. The consistency of intra-individual urinary measurements over the 4 test nights also was quite high (P < 0.01) in the sham control condition. In contrast, repeated nightly exposure to the magnetic field was associated with reduced consistency. Morning urinary measures obtained after exposure on night 4 differed (P < 0.01) from similar measures obtained after the second and third exposure night. Thus, while the overall results of this study do not support the melatonin hypothesis, there is some suggestion of a possible cumulative effect of magnetic field exposure on the stability of individual melatonin measurements over time. Additional research with longer periods of controlled exposure may be warranted.

Adolescent↗
PubMed2000

Morning urinary assessment of nocturnal melatonin secretion in older women.

We evaluated the feasibility of using morning urine samples in epidemiological studies aimed at clarifying the relationship between nocturnal melatonin levels and breast cancer risk. Initially, a laboratory-based study of 29 women (40- 70 yr old) was performed to examine the correlation between plasma melatonin levels in hourly nocturnal blood samples and both melatonin and its major enzymatic metabolite, 6-hydroxymelatonin-sulfate (6-OHMS) in morning urine samples. In a companion field study, morning urine samples were collected from 203 healthy women to assess similarities and differences in laboratory versus field measures. Taken together, our results indicate: 1) levels of melatonin and of creatinine-corrected 6-OHMS in the first morning void urine are strongly correlated with total nocturnal plasma melatonin output (P < 0.001) and also with peak nocturnal melatonin values (P < 0.001); 2) similar ranges for 6-OHMS were found in the laboratory and the field; and 3) neither menopausal status nor hormonal replacement therapy altered 6-OHMS values in morning void urine. The inclusion of morning urine samples in epidemiological studies of cancer could allow cost-effective, widespread testing of the role played by melatonin in human health and disease.

Adult↗
PubMed2000

Cardiac autonomic control mechanisms in power-frequency magnetic fields: a multistudy analysis.

Heart rate variability (HRV), a noninvasive indicator of autonomic control of cardiac activity, is predictive of long-term cardiac morbidity and mortality. Epidemiologic research suggests that occupational exposure to power-frequency magnetic fields may be associated with autonomically mediated cardiac mortality. Results from our laboratory studies of humans exposed to 60-Hz magnetic fields overnight, however, are inconsistent. HRV is altered in some studies but not others. To clarify this, the pooled data from seven studies involving 172 men were analyzed to test specific hypotheses concerning this inconsistency. After analysis, we excluded a) measurement drift or instability over time because HRV was stable under sham-exposed conditions across all studies; b) inadequate statistical power or failure to maintain double-blind controls; c) differences in field intensity (28.3 vs. 127.3 microT) or exposure pattern (intermittent versus continuous) as main effects; or d) the inclusion of individuals sensitive to magnetic field exposure in some studies but not others. Four separate analytic techniques failed to identify a valid subpopulation of sensitive individuals. In some studies, however, hourly blood samples were collected using an indwelling venous catheter. HRV alterations occurred during intermittent exposure in these studies (p < 0.05) but not in similar studies without blood sampling. This result suggests a field interaction with modest arousal or disturbance. Because HRV is tightly coupled to electroencephalographic activity during sleep, these results are physiologically plausible and suggest that HRV alterations during exposure to magnetic fields may occur when accompanied by increases in physiologic arousal, stress, or sleep disturbance.

Adolescent↗
PubMed2000

Exposure to strong ELF magnetic fields does not alter cardiac autonomic control mechanisms.

Clinical and epidemiological studies attest that alterations in heart rate variability (HRV) are predictive of specific types of cardiovascular morbidity and mortality in otherwise healthy persons. Recent reports also suggest that changes in HRV may be associated with exposure to intermittent magnetic fields (60 Hz, 28.3 microT) in the laboratory and that mortality is increased in cardiac disease categories related to altered HRV for utility workers whose jobs involve longer exposure to elevated magnetic fields. This study combined three approaches to learn more about the specific exposure circumstances under which changes in HRV occur. First, cardiac autonomic control, as indexed by HRV spectral analysis measures, was measured in 24 men during exposure to a much higher intensity field than any previously examined (resultant flux density = 127.3 microT [1273 milliGauss, mG]). Second, HRV measures from the same individual were compared across three relevant test conditions: intermittent and continuous field exposure and during a no-exposure, control condition. Third, electrocardiographic data were analyzed to determine if the precise timing of when the magnetic field switched on or off in relation to the cardiac cycle results in phase-resetting of the human cardiac rhythm. HRV measures were not altered by either field exposure condition compared to the control condition, and no evidence for a phase-resetting mechanism was found. Further research is needed to resolve the differences between the present and the earlier laboratory-based studies of HRV and to determine if cardiac rhythm disturbances are associated with exposure to the more complex magnetic fields found in the man-made environment.

Adult↗
PubMed2000

Heart rate variability and physiological arousal in men exposed to 60 Hz magnetic fields.

In previous research, intermittent exposure to sinusoidal 60 Hz magnetic fields at a resultant flux density of 28.3 microT was found to alter heart rate variability (HRV) in men during night sleep. When the 24 men in the present study were exposed under similar conditions, HRV was not altered. The previous studies included the hourly collection of blood samples via an indwelling venous catheter, while the present study did not. This may account for the observed differences in results. Further research is needed to determine if field exposure interacts with physiological arousal mechanisms to alter autonomic nervous system control over cardiac rhythms.

Adolescent↗
PubMed2000

Staying on top of TB's rise.

Delays in acid-fast bacillis (AFB) emergency department admissions prompted a revised multidisciplinary rounds process for weekends and holidays; AFB isolation cases dropped 10%.

Bacteriological Techniques↗
PubMed1999

Test facility for human exposure to AC and DC magnetic fields.

For more than a decade, Midwest Research Institute (MRI) has investigated the effects of exposure to 60 Hz electric and magnetic fields (EMF) on human physiology, performance, and biochemistry. This accumulated experience, new research directions, and limited resources made it important to design more comprehensive and operationally cost-effective exposure facilities. Here we describe the new, integrated laboratory exposure test facilities recently constructed at MRI and present data on relevant characteristics of the exposure systems. Concentric coil systems were developed to generate uniform magnetic fields within the three new exposure rooms, with rapid cancellation of the field to ambient levels in the rest of the laboratory. Control systems are fully automated, computer-based, and independent. These provide the operational flexibility needed to present fields of different magnitudes, frequencies, and polarization. The local geomagnetic field can be modulated and/or canceled, and both AC and DC fields can be presented in various combinations. Capabilities for conducting double-blind experiments with true active-sham exposure conditions were implemented using bifilar windings and applying current flow in the opposite direction for each wire in a pair. The new facilities provide a comprehensive capability for laboratory-based human research on the potential effects of exposure to AC and DC magnetic fields.

Automation↗