Factors associated with tuberculin conversion in Canadian microbiology and pathology workers

The risk of occupational tuberculosis (TB) infection and associated factors was estimated among all microbiology and pathology technicians and compared with a sample of nonclinical personnel in 17 Canadian acute care hospitals. Participants underwent tuberculin skin testing and completed questionnaires. Prior skin tests and vaccinations and all patients with TB hospitalized in the preceding 3 years were reviewed. Of the work areas where direction of air flow and air changes per hour were measured, only 51% were adequately ventilated. Among participating lab workers the average annual risk of tuberculin conversion was 1.0%. This was associated with lower hourly air exchange rates (16.7 versus 32.5 in workers with no conversion, p < 0.001) work in pathology (adjusted odds ratio [OR]: 5.4; [95% confidence interval: 1.3, 22], higher proportion of patients with missed diagnosis in the first 24 hours (per 20% increase-OR: 2.0; [1.3, 3.2], treatment delayed 1 week or more (per 20% increase-OR: 2.0; [3.2, 3.2]), and higher mortality (per 20% increase-OR: 2.5; [1.1, 5.6]). We conclude that laboratory workers, with no direct patient contact, have increased risk of tuberculin conversion in hospitals where a greater proportion of patients with TB die, or have delayed, or missed diagnosis, although this may be modified by workplace ventilation.     

A meta-analysis of the effect of Bacille Calmette Guérin vaccination on tuberculin skin test measurements

BACKGROUND: The accurate diagnosis of latent tuberculosis infection (LTBI) is an important component of any tuberculosis control programme and depends largely on tuberculin skin testing. The appropriate interpretation of skin test results requires knowledge of the possible confounding factors such as previous BCG vaccination. Uncertainty about the effect of BCG vaccination on tuberculin skin testing and the strength with which recommendations are made to individual patients regarding treatment of LTBI have identified a need to analyse the available data on the effect of BCG on skin testing. A meta-analysis of the evidence for the effect of BCG vaccination on tuberculin skin testing in subjects without active tuberculosis was therefore performed. METHODS: Medline was searched for English language articles published from 1966 to 1999 using the key words "BCG vaccine", "tuberculin test/PPD", and "skin testing". Bibliographies of relevant articles were reviewed for additional studies that may have been missed in the Medline search. Articles were considered for inclusion in the meta-analysis if they had recorded tuberculin skin test results in subjects who had received BCG vaccination more than 5 years previously and had a concurrent control group. Only prospective studies were considered. The geographical location, number of participants, type of BCG vaccine used, type of tuberculin skin test performed, and the results of the tuberculin skin test were extracted. RESULTS: The abstracts and titles of 980 articles were identified, 370 full text articles were reviewed, and 26 articles were included in the final analysis. Patients who had received BCG vaccination were more likely to have a positive skin test (5 TU PPD: relative risk (RR) 2.12 (95% confidence interval (CI)1.50 to 3.00); 2 TU RT23: 2.65 [corrected] (95% CI 1.83 to 3.85). The effect of BCG vaccination on PPD skin test results was less after 15 years. Positive skin tests with indurations of >15 mm are more likely to be the result of tuberculous infection than of BCG vaccination. CONCLUSIONS: In subjects without active tuberculosis, immunisation with BCG significantly increases the likelihood of a positive tuberculin skin test. The interpretation of the skin test therefore needs to be made in the individual clinical context and with evaluation of other risk factors for infection. The size of the induration should also be considered when making recommendations for treatment of latent infection.     

Survey of arthroscopy performed by rheumatologists

OBJECTIVE: To determine the international distribution and practice of arthroscopy performed by rheumatologists and to evaluate proposed guidelines on minimum standards for training in arthroscopy in the context of current clinical practice. METHODS: A questionnaire was sent to all rheumatology centres identified as practising arthroscopy, by (i) searching Medline from 1966 to 1999, (ii) searching the abstract books of the annual general meetings of ACR, BSR and EULAR from 1980 to 1999, and (iii) correspondence with all the centres identified. RESULTS: Thirty-six rheumatology centres were confirmed as performing arthroscopy (24 in Europe, 10 in USA and two in Australia) and 33 (92%) centres completed the questionnaire. Twenty-five (76%) of the 33 centres performing arthroscopy had started to perform it since 1990 and 72 rheumatologists are now trained in arthroscopy. A total of 16532 arthroscopies had been performed (median=220 arthroscopies/centre, range 20-5000); 50.5% of the arthroscopies had a primary clinical indication and 49.5% had a primary research indication. Most centres fulfilled the minimum standards for arthroscopic facilities and the proposed minimum standards in training were acceptable to 76% of respondents. Complication rates were calculated for 15682 arthroscopies where routine follow-up data were available [joint infection, 16 (0.1%); wound infection, 17 (0.1%); haemarthrosis, 141 (0.9%); deep venous thrombosis, 31 (0.2%); neurological damage, 3 (0.02%), thrombophlebitis, 12 (0.08%), other, 8 (0.06%)]. Irrigation volume correlated with wound infection rate (r=0.41, P=0.03) and centres performing cartilage biopsy had a higher rate of haemarthrosis (P=0.007). CONCLUSION: The last decade has seen rapid growth in arthroscopy performed by rheumatologists in an out-patient setting under local and regional anaesthesia. Proposed minimum standards for training in rheumatological arthroscopy reflect current practice accurately and are acceptable to the majority of arthroscopists. Complication rates of rheumatological arthroscopy are similar to those reported in the orthopaedic literature.     

AP-1 activity during the growth, differentiation, and death of O-2A lineage cells

Oligodendrocyte differentiation has been correlated with AP-1 activity, being low in progenitors and high in differentiated cells. In this study we have carried out a detailed temporal analysis of AP-1 activity in oligodendrocyte-type-2 astrocyte (O-2A) lineage cells. We show that low AP-1 activity in progenitor cells depended on the application of growth factors. Treatment of cells with B104-conditioned medium induced high AP-1 activity, increased process length, and improved growth. The role of AP-1 in proliferation and process extension was emphasized when progenitor cells overexpressing a c-Jun dominant-negative mutant had impaired growth and shortened processes. AP-1 DNA-binding activity during O-2A differentiation in vitro showed an initial down-regulation followed by up-regulation after 2 days. Increased AP-1 levels in oligodendrocytes were inhibited by overexpression of bcl-2, indicating that AP-1 in mature oligodendrocytes is involved in the regulation of apoptosis. Prevention of cell death by bcl-2 in oligodendrocytes was accompanied by progressive differentiation and expression of MOG and PLP.     

Complex repetitive discharges during urethral sphincter EMG: clinical correlates

Complex repetitive discharges (CRDs) are a form of abnormal needle electromyographic (EMG) activity associated with a variety of neuromuscular disorders, including chronic denervation. Urethral CRDs have also been associated with symptoms of voiding dysfunction. We reviewed the findings of 351 consecutive urethral sphincter EMG studies to characterize the patients with CRDs in our patient population and further to characterize the peri-operative course of any patient with urethral CRDs who underwent surgery for genuine stress incontinence (GSI). Among the 351 women studied, a subgroup of 27 (8%) women demonstrated CRDs during their study. Patients with CRDs were more likely to report the symptom of strain voiding (48% of patients with CRDs, 18% of patients without CRDs; chi(2)((1)) = 17.6, P < 0.001). Patients with CRDs were also more likely to have undergone prior urethral dilation (15% of patients with CRDs versus 2% of patients without CRDs, chi(2)((1)) = 9.5, P < 0.01). Patients with CRDs were similar to patients without CRDs with respect to symptoms of incontinence and history of hysterectomy or surgery for incontinence. Ten patients who had urethral CRDs underwent surgery for their GSI with a 90% success rate. The duration of post-operative catheterization did not differ from that of our general population of patients undergoing similar procedures. Urethral CRDs appear to be a non-specific finding, and it is premature to alter the approach to patients with lower urinary tract dysfunction for this reason.     

Interpretation of random urinary catecholamines and their metabolites in neuroblastoma

O'Meara A, Tormey W, Fitz Gerald RJ, Fitzgibbon M, Kenny D. Interpretation of random urinary catecholamines and their metabolites in neuroblastoma. Acta Paediatr 1994;83:88–92. Stockholm. ISSN 0803–5253
This study reports experience in the estimation of urinary catecholamines (uCATs) and their metabolites in the diagnosis and follow-up of neuroblastoma. Random urine samples were assayed for dopamine, noradrenaline and adrenaline, together with their metabolites 4-hydroxy 3-methoxyman-delic acid (HMMA) and homovanillic acid (HVA), using HPLC with electrochemical detection. Twenty of 21 patients had elevation of one or more uCATs metabolites at diagnosis. Patients were monitored serially from diagnosis and, in those patients who had delayed resection of primary tumour (n=13), particular attention was paid to levels at the pre-surgical evaluation as an indicator of persistence of viable disease at the time of surgery; dopamine proved to be the most accurate indicator of persistent disease at this time. Five of these patients developed recurrent disease, 4 of whom had elevation of two or more uCATs metabolites at the time of relapse. Several conclusions can be drawn from this study: (a) results for HMMA, HVA and dopamine in random urine samples will detect all but the most biochemically immature or inert tumours; (b) dopamine may be the most reliable indicator of persistent disease and (c) noradrenaline and adrenaline measurements were of little benefit. As results are Expressed in relation to urinary creatinine, excretion of which may be affected by dietary protein and is therefore not constant, borderline results should be repeated.