UK laboratory intercomparison on internal dosimetry

A laboratory intercomparison for internal dose assessment from a variety of intake scenarios is described. This is the first UK intercomparison using the revised ICRP Human Respiratory Tract and biokinetic models. Four United Kingdom laboratories participated and six cases were assessed. Overall, the agreement in internal dose assessments between laboratories was considered satisfactory with 79% of the assessed committed effective doses, e(50), for cases within a band of +/- 40% of the median value. The range (highest/lowest) in e(50) estimated by the laboratories was smallest (1.2) for a case involving inhalation of 137Cs. The range was greatest (6.0) for a case involving a wound with, and possible inhalation of, 238Pu, 239Pu and 241Am; the variation between laboratories in assessment of intakes could not be considered to be satisfactory in this case. Judgements on the most appropriate data to use in estimating intakes, choice of parameter values for use with the ICRP models and allowing for the effects of treatment with DTPA were important sources of variability between laboratories.

Intravenous antibiotic regimens and prophylaxis of odontogenic bacteraemia

OBJECTIVES

This study retrospectively examines the efficacy of prophylactic intravenous antibiotic regimens in the prevention of odontogenic bacteraemia in children with severe congenital heart defects receiving comprehensive dental treatment under general anaesthesia.

PATIENTS AND METHODS

Blood cultures were taken from children with congenital cardiac defects 30 seconds after completion of dental treatment under general anaesthesia. Antibiotic prophylaxis had been given intravenously immediately before dental treatment. The choice of antibiotics and the extent of dental treatment were recorded. The percentage prevalence of bacteraemia was compared with published data following multiple dental extractions using the same clinical and microbiological methodology.

RESULTS

The overall percentage prevalence of positive cultures in children receiving intravenous prophylactic antibiotics was 16%. The percentage of positive blood cultures in cardiac children who received ampicillin alone was not significantly different from that in children having a combination of amikacin and teicoplanin (16.7% v 22.2%) respectively [Chi Square = 0.385, df = 1, P= 0.535]. When compared with multiple extractions, both ampicillin alone and amikacin with teicoplanin were effective in reducing the prevalence of odontogenic bacteraemia.

CONCLUSIONS

In children with cardiac defects, bacteraemia after dental treatment is reduced by antibiotics but is still detected on 16% of occasions. In comparison with children receiving ampicillin alone, the combination of amikacin and teicoplanin is as effective in reducing bacteraemia in children who are either allergic to penicillins or who have received them within the previous month.

'Mirror image' distal anterior cerebral artery aneurysms. A case report of two patients with review of literature

We report two cases of patients with bilateral 'mirror image' or 'kissing' aneurysms at the distal anterior cerebral arteries who presented with subarachnoid haemorrhage and frontal intracerebral haematoma.

Bronchial challenges with aerosolized food in asthmatic, food-allergic children

BACKGROUND

Allergic asthma is usually considered to be provoked by aeroallergens. However, we have recently recognized a group of children with food allergies who also develop asthma when exposed to the aerosolized form of the food.

METHODS

Between 1997 and 1999 we prospectively identified children with an immunoglobulin (Ig)E-mediated food allergy who develop asthma on inhalational exposure to the relevant food allergen while it is being cooked. Subjects were exposed for 20 min to the aerosolized form of the allergen and the symptoms and the lung function were monitored. Aerosolization was achieved by cooking the food in a small room. Where possible challenges were double-blinded.

RESULTS

We identified 12 children with an IgE-mediated food allergy who developed asthma on inhalational exposure to food. The implicated foods were fish, chickpea, milk, egg or buckwheat. Nine out of the 12 children consented to undergo a bronchial food challenge. Five challenges were positive with objective clinical features of asthma. Additionally, two children developed late-phase symptoms with a decrease in lung function. Positive reactions were seen with fish, chickpea and buckwheat. There were no reactions to the seven placebo challenges.

CONCLUSIONS

We have presented a prospective series of children with food allergy who developed symptoms of asthma with exposure to aerosolized food allergens. Our data demonstrates that, as in the case of other aeroallergens, inhaled food allergens can produce both early- and late-phase asthmatic responses. This highlights the importance of considering foods as aeroallergens in children with coexistent food allergy and allergic asthma. For these children, dietary avoidance alone may not be sufficient and further environmental measures may be required to limit exposure to aerosolized food.

Interference effects in femtosecond spectroscopy

This article aims to provide a short synopsis of interference effects connected with ultrafast laser pulses, where 'ultrafast' is defined as ca. 100 fs or faster. The discussion is divided into three parts: the first shows how interference between waves is responsible for generation of light pulses in the femtosecond and attosecond time domains; the second describes characterization of ultrafast pulses by different interferometric techniques, including diffraction of femtosecond light by a double slit; and the final section discusses selected measurements of interference phenomena created and probed with femtosecond time resolution, with an emphasis on experiments in atomic physics. The article attempts to illustrate how wave-like interference is a unifying concept that pervades much of physics on a femtosecond time-scale.

Prevalence and antibiotic resistance profile of mercury-resistant oral bacteria from children with and without mercury amalgam fillings

Genes encoding resistance to mercury and to antibiotics are often carried on the same mobile genetic element and so it is possible that mercury-containing dental materials may select for bacteria resistant to mercury and to antibiotics. The main aim of this study was to determine whether the prevalence of Hg-resistant oral bacteria was greater in children with mercury amalgam fillings than in those without. A secondary aim was to determine whether the Hg-resistant isolates were also antibiotic resistant. Bacteria in dental plaque and saliva from 41 children with amalgam fillings and 42 children without such fillings were screened for mercury resistance by cultivation on a HgCl(2)-containing medium. Surviving organisms were identified and their susceptibility to mercury and to several antibiotics was determined. Seventy-eight per cent and 74% of children in the amalgam group and amalgam-free group, respectively, harboured Hg-resistant bacteria; this difference was not statistically significant. Nor was there any significant difference between the groups in terms of the proportions of Hg-resistant bacteria in the oral microflora of the children. Of Hg-resistant bacteria, 88% and 92% from the amalgam group and the amalgam-free group, respectively, were streptococci; 41% and 33% were resistant to at least one antibiotic, most frequently tetracycline. The results of this study show that there was no significant difference between children with amalgam fillings and those without such fillings with regard to the prevalence, or the proportion, of Hg-resistant bacteria in their oral microflora. The study also found that Hg-resistant bacteria were common in children regardless of whether or not they had amalgam fillings and that many of these organisms were also resistant to antibiotics.

Use of night-time benzodiazepines in an elderly inpatient population

AIM

To examine benzodiazepine prescribing for sleep induction in an elderly medical inpatient population to determine if hospital prescribing may have encouraged benzodiazepine use following discharge. Secondary objectives included assessment of quality of sleep in hospital compared with home and monitoring for possible benzodiazepine side-effects.

METHOD

Inpatient and discharge prescribing of benzodiazepines used for sleep induction were recorded in two medical wards over a 3-month period. A questionnaire was used to obtain information on patients' sleep patterns at home and in hospital. A follow-up telephone survey at 2-3 weeks post-discharge was made for those patients who were prescribed benzodiazepine at discharge.

RESULTS

Benzodiazepines were prescribed for 20% of patients with 94% of prescriptions being for temazepam. Of the 54 patients prescribed benzodiazepines during admission, 57% were not taking a benzodiazepine at home prior to their hospital admission. At discharge, 14 patients were prescribed benzodiazepines for home use, eight of whom had not used them at home previously. On follow-up none of these eight patients expressed a desire to continue benzodiazepine use for sleep induction. There was a significant (P < 0.05) reduction in sleep onset latency and number of nocturnal awakenings in hospital when compared with home. There was no change in sleep duration and overall quality of sleep. There was an association between early morning insomnia and benzodiazepine use.

CONCLUSION

Discharge prescribing of benzodiazepines was appropriately limited to temazepam and did not encourage home use in previous non-users. Benzodiazepines (primarily temazepam) were effective in the short term for inducing sleep in the hospital setting, with little evidence of side-effects.

Adherence discourse among African-American women taking HAART

Low adherence is the single most important challenge to controlling HIV through the use of high acting anti-retrovirals (HAART). Non-adherence poses an immediate threat to individuals who develop resistant forms of the virus as well as a public health threat if those individuals pass on treatment-resistant forms of the virus. To understand the concerns and perceptions that promote or deter adherence to antiretroviral medication by HIV-positive African-American women, we conducted in-depth interviews with 15 African-American women taking HAART. We focused on the discourse and narratives women use in talking about their adherence practice. Discourse analysis was utilized to identify and explore the sources of influence used by these women in describing their adherence practice. Roughly a third of the sample fell into each of the three self-assessed adherence categories: always adherent, mostly adherent and somewhat adherent. Among the 'always adherent', 80% of the sources of influence cited supported adherence, while only 48% and 47% of the authoritative sources cited by women in the 'mostly' and 'somewhat' categories supported adherence. Each self-assessed adherence group was characterized by its own distinctive discourse style. Findings suggest that adherence to HAART among African-American HIV-positive women would be improved by identifying those influences undermining adherence. Focused study of the 'always adherent' types is recommended.

Extramedullary myeloid cell tumours localised to the mediastinum: a rare clinicopathological entity with unique karyotypic features

Extramedullary myeloid cell tumour (EMMT) localised to the mediastinum is a rare manifestation of acute myeloid leukaemia, forming less than 4% of all cases of EMMT. In contrast to other types of EMMT, cytogenetic characteristics of this rare entity are relatively unknown. This report describes a patient with EMMT who had evidence of superior vena cava syndrome and normal peripheral blood counts at diagnosis. The results from an initial biopsy specimen were consistent with a diagnosis of mediastinal large B cell lymphoma. A diagnosis of acute myeloid leukaemia was made three months after initial diagnosis by bone marrow examination. Review of the initial biopsy specimen showed strong positivity for myeloperoxidase, revealing that the patient had been initially misdiagnosed as having large B cell lymphoma. Cytogenetic studies revealed a near triploid and near tetraploid karyotype with structural abnormalities in 12 and three metaphases, respectively. Review of the literature showed that a near tetraploid or triploid karyotype is found in most of the reported cases of mediastinal EMMT. Thus, the presence of a near triploid/tetraploid karyotype and mediastinal EMMT may represent a specific subset of EMMT. The biological relevance of this observation is discussed.

Inhaled corticosteroid effects on bone metabolism in asthma and mild chronic obstructive pulmonary disease

BACKGROUND

Inhaled corticosteroids form the main therapy for asthma, but there is increasing concern about the potential systematic effects of long-term inhaled corticosteroids including their effect on bone metabolism and bone loss.

OBJECTIVES

To determine the effect of inhaled corticosteroids use on biochemical markers of bone turnover, bone mineral density and the development of fractures.

SEARCH STRATEGY

We searched the Cochrane Airways Group trials register, electronic reference databases, UK National Research Register, bibliographies of included studies, and contacted pharmaceutical companies.

SELECTION CRITERIA

Randomised trials of the effect of inhaled steroid versus placebo on markers of bone function and metabolism, in adults with asthma or mild COPD.

DATA COLLECTION AND ANALYSIS

Trial quality was assessed and data extracted from the papers included (2 reviewers per paper) and from additional data supplied by the authors.

MAIN RESULTS

Of 438 references found, seven met the inclusion criteria. Three studies were in healthy subjects asthma or COPD. The patients were generally less than 60 years old and the male:female ratio was 2:1. There was no evidence of increased risk of loss of bone mineral density (BMD) or fractures. There was no significant change in osteocalcin at conventional doses of inhaled corticosteroids (Standardised Mean Difference [SMD] -0.34 (95% Confidence Interval [CI] -0.72, 0.04), although a statistically significant change was seen in those studies using experimental doses of inhaled steroid in excess of the doses recommended by the British Thoracic Society SMD 0.97 (95% CI -1.61, -0.34). A statistically significant change in parathyroid hormone seen in one small short trial (n=10, 6 weeks) may have been due to the trial design and outcome measurements used.

REVIEWER'S CONCLUSIONS

In patients with asthma or mild COPD, there is no evidence of an effect of inhaled corticosteroid at conventional doses given for two or three years on BMD or vertebral fracture. Higher doses were associated with biochemical markers of increased bone turnover, but data on BMD and fractures at these doses are not available. There is a need for further, even longer term prospective studies of conventional and high doses of inhaled corticosteroids.

Comparison of the BACTEC MYCO/F Lytic bottle to the isolator tube, BACTEC Plus Aerobic F/bottle, and BACTEC Anaerobic Lytic/10 bottle and comparison of the BACTEC Plus Aerobic F/bottle to the Isolator tube for recovery of bacteria, mycobacteria, and fungi from blood

The BACTEC MYCO/F Lytic blood culture bottle (Becton Dickinson Diagnostic Instrument Systems, Sparks, Md.) is designed to optimize the recovery of fungi and mycobacteria; however, this bottle also supports the growth of most aerobic bacteria. We compared the MYCO/F Lytic bottle with two other BACTEC bottles and the Isolator system for the recovery of bacteria as well as fungi and mycobacteria from blood. A total of 6,108 blood culture sets were inoculated with blood obtained from adult patients. Twenty-five to 28 ml of blood collected by a phlebotomy team for each blood culture set was randomly distributed into each of four blood culture receptacles: the Isolator tube (Wampole Laboratories, Cranbury, N.J.) and three BACTEC bottles: the MYCO/F Lytic bottle, the BACTEC Plus Aerobic/F bottle, and the BACTEC Anaerobic Lytic/10 bottle. The sediment from the Isolator tube was inoculated onto chocolate agar (CA), brain heart infusion agar (BHI), and Sabouraud dextrose agar (SDA) and into a BACTEC 13A bottle. Incubation durations were as follows: MYCO/F Lytic bottle, 42 days; Plus Aerobic/F bottle, 5 days; Anaerobic Lytic/10 bottle, 5 days; sediment from Isolator tube on CA, 3 days; sediment from Isolator tube on BHI, 30 days; sediment from Isolator tube on SDA, 30 days; and sediment from Isolator tube in a BACTEC 13A bottle, 42 days. Two isolates of Histoplasma capsulatum were recovered from the Isolator tube only. Three isolates of Mycobacterium tuberculosis complex were recovered: two isolates from the MYCO/F Lytic bottle only and one isolate from the Isolator tube (whose sediment was inoculated into the BACTEC 13A bottle) only. Two isolates of Cryptococcus neoformans were recovered: one from the MYCO/F Lytic bottle only and the other from the MYCO/F Lytic bottle and the Isolator tube (whose sediment was inoculated into the BACTEC 13A bottle). For potential pathogens overall, there was a statistical difference in recovery that favored the Isolator system over the MYCO/F Lytic bottle (P = 0.0015), including statistically significant differences for Staphylococcus aureus (P = 0.0001) and Streptococcus pneumoniae (P = 0.0313). However, there was no statistically significant difference between the two blood culture systems when detection of bloodstream infection was considered. The time to detection for all potential pathogens combined was less for the MYCO/F Lytic bottle than for the Isolator system (P = 0.0004). Overall, the potential pathogen recovery was greater for the BACTEC Plus Aerobic/F bottle than for either the Isolator system (P = 0.0003) or the MYCO/F Lytic bottle (P = 0.0001). However, the BACTEC Plus Aerobic/F bottle did not recover M. tuberculosis, H. capsulatum, or C. neoformans isolates. The combination of the Isolator system and MYCO/F Lytic bottle may be useful as a selective blood culture method to optimize the recovery of fungi and mycobacteria from blood. Compared with the manual Isolator system, the MYCO/F Lytic system has the advantage of less preanalytic processing and continuous automated monitoring of bottles for growth by the BACTEC 9240 instrument.

The reproducibility of assessing radiological reporting: studies from the development of the General Medical Council's Performance Procedures

OBJECTIVES

To investigate the reproducibility of peer ratings of consultant radiologists' reports, as part of the new General Medical Council (GMC) Performance Procedures.

DESIGN

An evaluation protocol was piloted, used in a blocked, balanced, randomized generalizability analysis with three blocks of three judges (raters), each rating 30 reports from 10 radiologists, and re-rated to estimate intrarater reliability with conventional statistics (kappa).

SETTING

Rating was performed at the Royal College of Radiologists. Volunteers were sampled from 23 departments of radiology in university teaching and district general hospitals.

PARTICIPANTS

A nationally drawn non-random sample of 30 consultant radiologists contributing a total of 900 reports. Three trained and six non-trained judges were used in the rating analysis.

RESULTS

A protocol was generated that was usable by judges. Generalizable results would be obtained with not less than three judges all rating the same 60 reports from a radiologist.

CONCLUSIONS

Any assessment of performance of technical abilities in this field will need to use multiple assessors, basing judgements on an adequate sample of reports.

Dietary habits and dental health over the first 18 months of life

OBJECTIVES

The main objective of this study was to describe the dental health of infants and toddlers with special reference to their dietary habits and oral hygiene behaviour over the first 18 months of life.

METHODS

The longitudinal dietary data were obtained at 6, 12 and 18 months of age by using a 3-day weighed diet diary. Dental examinations were carried out at 12, and again at 18 months of age. The information on demographic factors and oral hygiene behaviours over the first 18 months of life was gathered by using a structured questionnaire at 12 and 18 months.

RESULTS

163 children were studied. Visible dental plaque was present in 18% and 25% of children at 12 and 18 months of age, respectively. No child had dental caries at either 12 or 18 months of age. There was a statistically significant correlation between visible plaque measured as plaque index at 12 months and the mean daily eating/drinking episodes at 6 months (r=0.25, P=0.001) and 12 months (r=0.15, P=0.05). The correlations between plaque index at 18 months and the mean eating/drinking episodes at both 12 months (r=0.2, P=0.04) and 18 months (r=0.2, P=0.02) were low but statistically significant. Nevertheless, there was no significant correlation between accumulation of plaque at either 12 or 18 months and the mean daily frequency consumption of food and drink containing non-milk extrinsic sugars (NMES) at any age. Children who brushed their teeth themselves were more likely to have visible plaque compared with children whose teeth were cleaned by their parents. The partial correlation showed that positive relation between mean daily eating/drinking episodes and plaque was not influenced by tooth brushing.

Distribution of endo-beta-N-acetylglucosaminidase amongst enterococci

Enterococci are becoming increasingly important nosocomial pathogens, a fact mainly attributed to their antimicrobial resistance profiles. However, the enzymic activities required for these organisms to proliferate in vivo have received little attention. Enterococcus faecalis has been shown previously to produce an endo-beta-N-acetylglucosaminidase activity which cleaves high mannose-type glycans in glycoproteins between the N-acetylglucosamine residues of the pentasaccharide core. This study investigated the distribution of this endoglycosidase activity amongst the other enterococcal species. Ribonuclease B, a high mannose-type glycoprotein, was used as a substrate and endoglycosidase activity was demonstrated by a combination of matrix-assisted laser desorption ionisation time-of-flight mass spectrometry and high pH anion-exchange chromatography. Endo-beta-N-acetylglucosaminidase activity was present in 10 of the 18 enterococcal species isolated from both human and animal sources, including all E. faecalis strains. The most notable exception was the lack of this activity in all E. faecium isolates tested. All enterococcal species possessing endoglycosidase activity utilised the liberated glycans to support bacterial growth.