Comparative Efficacy of Rotator Interval Versus Posterior Capsule Approach Intraarticular Corticosteroid Injections for Primary Frozen Shoulder: A Single-blind, Randomized Trial

BACKGROUND

Intraarticular (IA) corticosteroid injection is commonly performed in patients with primary frozen shoulder (PFS). However, the best administration site remains controversial.

OBJECTIVES

To compare the efficacy of rotator interval (RI) vs posterior capsule (PC) approach for ultrasound-guided corticosteroid injections into the glenohumeral joint of patients with PFS.

STUDY DESIGN

A randomized, exploratory, prospective study.

SETTING

A single fellowship training institution in Daegu, Republic of Korea.

METHODS

This study was approved by the Institutional Review Board (2019-04-047-001).  Ninety patients with PFS were randomly assigned to either RI approach (RI group, n = 43) or PC approach (PC group, n = 45) for ultrasound-guided IA corticosteroid injection. Fluoroscopic images to assess the accuracy of the injection were obtained immediately after injection by a shoulder specialist. Visual Analog Scale for pain, the American Shoulder and Elbow Surgeons score, the subjective shoulder value, and range of motion (ROM) were used to assess clinical outcomes for all patients at the time of presentation, and at 3, 6, and 12 weeks after injection.

RESULTS

The accuracy of injection was 76.7% (33/43) and 93.3% (42/45) in the RI and PC groups, respectively; the between-group difference was statistically significant (P = .028). Significant improvements were observed in both groups in terms of all clinical scores and ROMs throughout follow-up until 12 weeks after the injection (all P < .001). At 12 weeks, better improvements in forward flexion and abduction (P = .049 and .044) were observed in the RI group than in the PC group. No adverse effect related to injection was observed in either group.

LIMITATIONS

This study had no control group receiving placebo injections and limited follow-up time.

CONCLUSIONS

Both groups showed significant pain reduction and functional improvement until 12 weeks after injection. Although no significant differences were observed in pain and functional scores between the 2 groups, the RI group showed better improvement of ROM than the PC group. These results indicate that the RI and anterior structures are a major site in the pathogenesis and treatment target of PFS.

Describing the population health burden of depression: health-adjusted life expectancy by depression status in Canada

INTRODUCTION

Few studies have evaluated the impact of depression in terms of losses to both premature mortality and health-related quality of life (HRQOL) on the overall population. Health-adjusted life expectancy (HALE) is a summary measure of population health that combines both morbidity and mortality into a single summary statistic that describes the current health status of a population.

METHODS

We estimated HALE for the Canadian adult population according to depression status. National Population Health Survey (NPHS) participants 20 years and older (n = 12 373) were followed for mortality outcomes from 1994 to 2009, based on depression status. Depression was defined as having likely experienced a major depressive episode in the previous year as measured by the Composite International Diagnostic Interview Short Form. Life expectancy was estimated by building period abridged life tables by sex and depression status using the relative risks of mortality from the NPHS and mortality data from the Canadian Chronic Disease Surveillance System (2007-2009). The Canadian Community Health Survey (2009/10) provided estimates of depression prevalence and Health Utilities Index as a measure of HRQOL. Using the combined mortality, depression prevalence and HRQOL estimates, HALE was estimated for the adult population according to depression status and by sex.

RESULTS

For the population of women with a recent major depressive episode, HALE at 20 years of age was 42.0 years (95% CI: 40.2-43.8) compared to 57.0 years (95% CI: 56.8-57.2) for women without a recent major depressive episode. For the population of Canadian men, HALE at 20 was 39.0 years (95% CI: 36.5-41.5) for those with a recent major depressive episode compared to 53.8 years (95% CI: 53.6-54.0) for those without. For the 15.0-year difference in HALE between women with and without depression, 12.3 years can be attributed to the HRQOL gap and the remaining 2.7 years to the mortality gap. The 14.8 fewer years of HALE observed for men with depression equated to a 13.0-year HRQOL gap and a 1.8-year mortality gap.

CONCLUSION

The population of adult men and women with depression in Canada had substantially lower healthy life expectancy than those without depression. Much of this gap is explained by lower levels of HRQOL, but premature mortality also plays a role.

On the nature of magnetic state in the spinel Co₂SnO₄

In the spinel Co2SnO4, coexistence of ferrimagnetic ordering below T(N) ≃ 41 K followed by a spin glass state below T(SG) ≃ 39 K was proposed recently based on the temperature dependence of magnetization M(T) data. Here new measurements of the temperature dependence of the specific heat C(P)(T), ac-susceptibilities χ'(T) and χ″(T) measured at frequencies between 0.51 and 1.2 kHz, and the hysteresis loop parameters (coercivity H(C)(T) and remanence M(R)(T)) in two differently prepared samples of Co2SnO4 are reported. The presence of the Co(2+) and Sn(4+) states is confirmed by x-ray photoelectron spectroscopy (XPS) yielding the structure: Co2SnO4 = [Co(2+)][Co(2+)Sn(4+)]O4. The data of C(P) versus T shows only an inflection near 39 K characteristic of spin-glass ordering. The analysis of the frequency dependence of ac-magnetic susceptibility data near 39 K using the Vogel-Fulcher law and the power-law of the critical slowing-down suggests the presence of spin clusters in the system which is close to a spin-glass state. With a decrease in temperature below 39 K, the temperature dependence of the coercivity H(C) and remanence M(R) for the zero-field cooled samples show both H(C) and M(R) reaching their peak magnitudes near 25 K, then decreasing with decreasing T and becoming negligible below 15 K. The plot of C(P)/T versus T also yields a weak inflection near 15 K. This temperature dependence of H(C) and remanence M(R) is likely associated with the different magnitudes of the magnetic moments of Co(2+) ions on the 'A' and 'B' sites and their different temperature dependence.

Sub-nanosecond time-resolved near-field scanning magneto-optical microscope

We report on the development of a new magnetic microscope, time-resolved near-field scanning magneto-optical microscope, which combines a near-field scanning optical microscope and magneto-optical contrast. By taking advantage of the high temporal resolution of time-resolved Kerr microscope and the sub-wavelength spatial resolution of a near-field microscope, we achieved a temporal resolution of ∼50 ps and a spatial resolution of <100 nm. In order to demonstrate the spatiotemporal magnetic imaging capability of this microscope, the magnetic field pulse induced gyrotropic vortex dynamics occurring in 1 μm diameter, 20 nm thick CoFeB circular disks has been investigated. The microscope provides sub-wavelength resolution magnetic images of the gyrotropic motion of the vortex core at a resonance frequency of ∼240 MHz.

Asthma in children: Management practices among paediatricians and family physicians

OBJECTIVE

To ascertain the variation in asthma management practices among paediatricians and family physicians to determine how to improve care.

DESIGN

Questionnaire study of paediatricians and family physicians that focused on the use of beta(2)-agonists, inhaled corticosteroids, patient asthma education, quantitative measurements of airflow and diagnostic investigations for asthma. Case scenarios were used in the questionnaire.

RESULTS

The response rate was 66% (415 of 632) among paediatricians and 42% (1156 of 2750) among family physicians. In general, both groups followed consensus guidelines. There were some differences in management practices among paediatricians and family physicians. Paediatricians were more likely to develop an action plan and less likely to use xanthines or inhaled anticholinergic agents. However, family physicians were more likely to use spirometry or home peak expiratory flow rates to make a diagnosis of asthma.

CONCLUSION

Family physicians and paediatricians require a different focus on educational interventions to improve the care of children with asthma.

Nonequilibrium domain pattern formation in mesoscopic magnetic thin film elements assisted by thermally excited spin fluctuations

The dynamic behavior in the evolving pattern of thermally assisted, nonequilibrium domains in magnetic thin-film elements undergoing ultrafast 180 degrees magnetization reversal was studied. Magnetization reversal enters a fully dynamic regime when the external field conditions are changed much faster than the sample is able to respond. The dynamic pathway develops a complexity not seen in quasistatic reversal but still retains a high level of order with well-developed dynamic domain patterns formed in response to subnanosecond transitions of the external applied magnetic field.

Radiation-spin interaction, Gilbert damping, and spin torque

Magnetization relaxation processes, which are represented by the Gilbert damping term and the spin torque term in the Landau-Lifshitz-Gilbert (LLG) equation, are described by the radiation-spin interaction (RSI), where the radiation field is produced by magnetization precessional motion itself. It is shown that the LLG equation including the Gilbert damping term and the spin torque term is derived from the spin Hamiltonian containing the RSI. The derivation of the LLG equation is given in a self-consistent method. It is also shown that, according to RSI, the magnitude of the magnetization vector deviates from the magnetization saturation with the order of O(alpha(2)), where alpha is the Gilbert damping parameter.

Effect of an oxytocin antagonist on plasma oxytocin levels during nocturnal uterine contractions in the pregnant baboon

TT-235 is a potent oxytocin (OT) antagonist that blocks the action of OT at the receptor level. Previous studies have shown that pregnant baboons demonstrate nocturnal uterine contractions induced by OT as they near delivery. The purpose of this study was to evaluate the changes in plasma OT levels following uterine contraction blockage with TT-235. A tethered pregnant baboon model in its last trimester of pregnancy was used. Three blocks of arterial blood samples, immediately before, plus 1 h and plus 2 h following an OT antagonist injection, were collected once nocturnal uterine contractions were detected. Each block consisted of a continuous 10 min withdrawal with 10 samples per block (1 ml/min). A TT-235 dosage of 300 micrograms/kg and saline for control were utilized. Uterine activities were monitored as pressure changes in the amniotic fluid, and the frequency and mean amplitude of contractile activity per 10 min intervals were expressed as contractile force. Plasma OCT levels were determined by a radioimmunoassay following plasma extraction with petroleum ether. The contractile force was decreased by 77% (p < 0.05) within 2 h after TT-235 administration while it increased 23% following saline infusion. Plasma OT levels were unchanged following saline infusion while they increased 82% (p < 0.05) 2 h after the administration of TT-235. If a positive feedback existed between uterine contractions and OT release, one would expect plasma OT levels to be decreased with contractile activity following TT-235 infusion. Since this is not the case in the present study, the data suggest that there is either a negative feedback or an independent relationship between nocturnal uterine contractions and OT release.

Lessons for surveillance in the 21st century: a historical perspective from the past five millennia

This paper reviews some major epidemics in the past 5,000 years in human history and derives 12 lessons in the context of epidemiologic surveillance. The corresponding 12 challenges proposed in this paper could be used to guide us in building a better and more comprehensive surveillance system in the 21st century. This will be achieved by: continuing the evolvement and improvement of surveillance; maintaining on an ongoing basis; being systematic; being population-based; including risk and intervention indicators in the data base; more efficient data analysis; stimulating etiologic research; improving forecasting capability; linking to development of intervention; evaluating the intervention; better ways of information dissemination; and dissemination without prejudice.

Mathematical procedure to adjust for the healthy worker effect: the case of firefighting, diabetes, and heart disease

This article presents a mathematical procedure to adjust for one component of the healthy worker effect (HWE), namely, the healthy hired effect, on diabetes in the case of firefighting and heart disease. Three examples from real studies are given to illustrate, step-by-step, the application of the mathematical procedure. The mathematical procedure can be applied to adjust for other components of the HWE (e.g., the low-risk hired effect on obese individuals and smokers). In such cases, additional information will be needed to use the mathematical procedure. Results of applying the mathematical procedure in the case of firefighting and heart disease revealed the rather unexpected results that adjusting for diabetes selection on hiring leads to only a 3% to 9% increase in the magnitude of ratio statistics such as the standardized mortality ratio. It might be argued that the HWE from one component such as the healthy hired effect on diabetes might be small, but together with other components, the HWE might be large. Further investigation will be needed to support this argument.

Developing regional workplace health and hazard surveillance in the Americas

An objective of the Workers' Health Program at the Pan American Health Organization (PAHO) is to strengthen surveillance in workers' health in the Region of the Americas in order to implement prevention and control strategies. To date, four phases of projects have been organized to develop multinational workplace health and hazard surveillance in the Region. Phase 1 was a workshop held in 1999 in Washington, D.C., for the purpose of developing a methodology for identifying and prioritizing the top three occupational sentinel health events to be incorporated into the surveillance systems in the Region. Three surveillance protocols were developed, one each for fatal occupational injuries, pesticide poisoning, and low back pain, which were identified in the workshop as the most important occupational health problems. Phase 2 comprised projects to disseminate the findings and recommendations of the Washington Workshop, including publications, pilot projects, software development, electronic communication, and meetings. Phase 3 was a sub-regional meeting in 2000 in Rosario, Argentina, to follow up on the progress in carrying out the recommendations of the Washington workshop and to create a Virtual Regional Center for Latin America that could coordinate the efforts of member countries. Currently phase 4 includes a number of projects to achieve the objectives of this Center, such as pilot projects, capacity building, editing a compact disk, analyzing legal systems and intervention strategies, software training, and developing an internet course on surveillance. By documenting the joint efforts made to initiate and develop Regional multinational surveillance of occupational injuries and diseases in the Americas, this paper aims to provide experience and guidance for others wishing to initiate and develop regional multinational surveillance for other diseases or in other regions.

Advances in magnetic microscopy

A remarkable number of methods for direct, real-space imaging in magnetic microscopy have been demonstrated over the past decade and a half, and the pace of development shows no sign of slowing. Our understanding of magnetism increases as each striking new image of surface and thin-film magnetization is obtained. The continued development of high-performance magnetic information technologies also requires detailed study of the magnetostatics and dynamics of microscopic magnetic structures. Both fundamental curiosity and practical interest now drive us toward innovations in magnetic microscopy for nanometer-length scale and femtosecond temporal resolutions, which are beyond the limits of traditional imaging techniques. This survey is intended to provide an overview of the motivations, accomplishments, and future prospects for this discipline.

Risk factors for diabetes mellitus by age and sex: results of the National Population Health Survey

AIMS/HYPOTHESIS

We aimed to assess the risk factors for diabetes mellitus, by age and sex in Canada and to recommend prevention and control strategies.

METHODS

This study was based on the Canadian 1996-1997 National Population Health Survey which comprised 69 494 participants aged 12 years and over. The prevalence of diabetes mellitus was analysed in relation to age, sex, body mass index, overweight status, energy expenditure, physical activity, smoking, drinking, income, marital status, education and rural or urban residence.

RESULTS

The prevalence of diabetes increased with age and body mass index and increased inversely with energy expenditure in both males and females. Current and former smokers were associated with a higher prevalence of diabetes. No effect was observed in regular or former drinkers. Prevalence of diabetes increased inversely with income, especially among women. Women who were single and 35 to 64 years old had a higher prevalence of diabetes than women of the same age who were married. The prevalence of diabetes was not found to be related to the level of education. Urban or rural residence was not found to have an effect on the prevalence of diabetes.

CONCLUSION/INTERPRETATION

Women and men of all ages should avoid becoming overweight, by maintaining their body mass index below 25 kg/m(2) and 27 kg/m(2), respectively. They should maintain a moderate level of physical activity. Patients with diabetes should give up smoking completely. Diabetes prevention and control strategies should be targeted for women in low income groups.

Role of placental tissues in the intrauterine transmission of hepatitis B virus

OBJECTIVE

The purpose of this study was to determine the mechanism of intrauterine transmission of hepatitis B virus.

STUDY DESIGN

Placental tissues from 158 pregnant women who tested positive for hepatitis B surface antigen were examined for hepatitis B virus markers, Fc gamma receptors, and hepatitis B surface antigen-anti-hepatitis B surface antigen in different layers of cells.

RESULTS

It was shown that the hepatitis B virus infection rate among different layers of placental cells gradually decreased from the maternal side to the fetal side. Furthermore, the closer the infected cell layer was to the fetal side, the higher the risk of intrauterine hepatitis B virus infection. Fc gamma receptors were found on cells of both hepatitis B surface antigen positive and negative placentas; Fc gamma receptors III were found on trophoblastic cells and villous mesenchymal cells, and Fc gamma receptors II were found on only villous mesenchymal cells. Hepatitis B surface antigen-antibodies to hepatitis B surface antigen was detected in the cytoplasm and on the membrane of trophoblastic cells and villous mesenchymal cells in 2 hepatitis B surface antigen-positive placentas.

CONCLUSION

The results support the hypothesis that intrauterine hepatitis B virus transmission could be caused through "cellular transfer" in the placenta. One of the means of cellular transfer could be through Fc gamma receptor III-mediated entry of hepatitis B surface antigen-antibodies to hepatitis B surface antigen into cells.

Short-term phytohaemagglutinin-activated mononuclear cells induce endothelial progenitor cells from cord blood CD34+ cells

Endothelial progenitor cells (EPCs) were recently demonstrated to exist in human cord blood. Phytohaemagglutinin (PHA), a potent mitogen for mononuclear cells was used to induce EPCs from unsorted cord blood mononuclear cells (CBMCs). Adherent cells in clusters appeared approximately 24 h after CBMCs were cultured in plain Roswell Park Memorial Institute media containing 10% fetal bovine serum (culture media) and PHA. Adherent cells were further propagated for 1 week in plain culture media. Flow cytometry and Di-I staining analyses showed that CD45-, CD34+, Flk-1+, CD31+ or VE-cadherin+ EPCs were induced and that they were mainly from the CD34+ cell compartment. When enriched CD34+ cells alone were stimulated with culture supernatant of the PHA-activated CBMCs, they neither proliferated readily nor induced EPCs. Because EPCs first appeared within the clustering cells that expressed high levels of fibronectin and vascular endothelial growth factor (VEGF), our data suggest that both cell-cell/cell-matrix interaction and the local VEGF action are important in the induction of EPCs. Thus, we demonstrate for the first time that EPCs are induced from human cord blood stem cell populations that interact with neighbouring PHA-activated CBMCs. This finding may have a significant implication in inflammatory cell-mediated vasculogenesis and angiogenesis in vivo.

Prioritization of occupational sentinel health events for workplace health and hazard surveillance: the Pan American Health Organization experience

Within the ongoing strategy of the Workers' Health program at the Pan American Health Organization on strengthening surveillance in the field of workers' health in the Americas (the Region), a project was conducted in July 1999 in Washington, D.C. The objectives of the project were to discuss the problems found in the surveillance of workers' health, to develop a methodology and use it to prioritize and select the top three occupational sentinel health events for incorporation into the surveillance systems in the Region, and to develop the initial protocols for establishing the surveillance systems for the three chosen occupational sentinel health events. The Pan American Health Organization invited 24 occupational health experts from the Region to participate in the project. Over an intensive 3-day period, the experts heard reports of workplace surveillance activities in the various countries in the Region; developed prioritization methods; identified and prioritized a list of occupational sentinel health events; and developed three surveillance protocols, one each for occupational fatal injuries, pesticide poisoning, and low back pain. The results on the prioritization of occupational sentinel health events and the development of surveillance protocols are reported in this article.

Ultrafast magnetization reversal dynamics investigated by time domain imaging

Spatiotemporal magnetization reversal dynamics in a Ni(80)Fe(20) microstructure is studied using ps time scale scanning Kerr microscopy. Time domain images reveal a striking change in the reversal associated with the reduction in switching time when a transverse bias field is applied. Magnetization oscillations subsequent to reversal are observed at two resonance frequencies, which sensitively depend on the bias field strength. The oscillation at f = 2 GHz is caused by the damped precession of M, while the lower frequency approximately 0.8 GHz mode is interpreted in terms of domain wall oscillation.

Pharmacokinetic changes of oral sulfamethoxazole in rabbits with diabetes mellitus induced by alloxan

Because physiological changes occurring in diabetes mellitus patients could alter the pharmacokinetics of the drugs used to treat infectious diseases resulting from diabetic complications, the pharmacokinetics of sulfamethoxazole (sulfamethoxazole is usually used to treat secondary infectious diseases resulting from diabetic mellitus) were investigated after oral administration of the drug (50 mg/kg) to control rabbits and rabbits with acute (experiment was performed at fifth day after two consecutive days intravenous administration of alloxan) and chronic (experiment was performed at thirteenth day after first, second, sixth, and tenth days intravenous administration of alloxan) diabetes mellitus induced by alloxan. Impaired kidney and liver functions were observed in acute and chronic diabetes mellitus groups based on plasma chemistry data, and liver and kidney microscopy. After oral administration of sulfamethoxazole to acute and chronic groups, the plasma concentrations tended to be higher and this resulted in a significantly greater area under the plasma concentration-time curve from time zero to time infinity, AUC (6001 and 3867 compared with 1569 microg h/ml). This could be due to significantly slower (2-3 times) renal clearance because of impaired kidney function. The effects of diabetes on the pharmacokinetics of oral sulfamethoxazole were more considerable in acute group; the AUC and the maximum plasma concentration were significantly greater and higher, respectively, than those in control and chronic groups. After oral administration, some pharmacokinetic parameters of sulfamethoxazole were significantly different in diabetes mellitus.

Physician asthma management practices in Canada

OBJECTIVES

To establish national baseline information on asthma management practices of physicians, to compare the reported practices with the Canadian Consensus recommendations and to identify results potentially useful for interventions that improve physician asthma management practices.

DESIGN

National, stratified cross-sectional survey.

SETTINGS

The 10 provinces and two territories of Canada, from 1996 to 1997.

PARTICIPANTS

Questionnaires were sent to 4489 physicians stratified by province/territory and specialty group (family/general practice, respirology, internal medicine, pediatrics and allergy/immunology); 2605 responses were received.

OUTCOME MEASURES

Methods for the diagnosis, treatment, education and follow-up of patients with asthma ('asthma management practices').

RESULTS

Significant variations existed among the five specialty groups in asthma management practices. A low use of objective measures of airflow limitation to assist with diagnosis was found among some respondents (mostly family physicians). Up to 40% of physicians regarded the daily fixed dosing (three or four times a day) of inhaled, short acting beta2-agonist as 'first-line therapy' for moderate to severe asthma. A minority of physicians reported using written action plans for patients or referring them to other health professionals for asthma education. Insufficient time during appointments and a perceived lack of appropriate educational materials were frequently cited as reasons for not providing asthma education. The perceived knowledge of the Canadian Consensus recommendations varied among physicians but was lowest among nonspecialists.

CONCLUSIONS

The survey showed variations in certain aspects of the management of asthma by physicians. The findings will help to target specific areas for future physician education programs and other behavioural change strategies.

A technique to re-assess epidemiologic evidence in light of the healthy worker effect: the case of firefighting and heart disease

The healthy worker effect (HWE) is a bias that is believed to have strongly affected the validity of previous cohort mortality studies on the relationship between firefighting and heart disease. There is a strong healthy hired effect (a component of the HWE) among firefighters, owing particularly to the recruitment of nondiabetic candidates. This is shown in previous studies in which the reported standardized mortality ratios for diabetes are much less than unity, generally around 0.3 to 0.5. Because diabetes is known to increase the risk of heart disease, a deficit of diabetes among firefighters is expected to lead to a deficit of heart injury and disease. This would make the cohort mortality studies incapable of detecting any increase in risk of heart injury and disease among firefighters. There is also a strong healthy worker survivor effect (another component of the HWE) among firefighters. In addition, heart disease is a classic example of the HWE because heart disease is chronic and its risk factors can be identified in the selection process. It is believed that (1) a major problem of previous studies on firefighting and heart disease is their failure to recognize the importance of the HWE when interpreting their results, and (2) a technique to re-assess results in light of the HWE is urgently needed. This article addresses the generally accepted principles relating to the HWE, including its definition and sources, and proposes a technique for re-assessing the literature in light of the HWE. The technique was applied to carefully re-assess 23 studies that provided direct evidence for the relationship between firefighting and heart disease. Before the re-assessment, 7 of the 23 studies showed positive evidence and 16 showed no evidence. After the re-assessment, 11 studies showed positive evidence and 12 showed no evidence. Based on the results of the re-assessment of the 23 studies, we concluded that (1) there is strong evidence of an increased risk of death overall from heart disease among firefighters; (2) there is insufficient evidence, even after considering the HWE, that there is an increased risk of death from aortic aneurysm among firefighters; and (3) there is insufficient evidence, even after considering the HWE, for a relationship between firefighting and any heart disease subtype, such as acute myocardial infarction.

Maternal immunological aspects of pregnancy success and failure

Historically, auto- and alloimmune maternal immunological abnormalities have been proposed to account for pregnancy loss. However, most of these immunological theories have not fulfilled the criteria for causality. Autoimmunity involving antibodies to cardiolipin and possibly phosphatidylserine is the immunological factor best associated with recurrent abortion in a condition known as the antiphospholipid syndrome, which occurs in < 5% of women undergoing recurrent pregnancy losses. Dichotomous T helper cell 1 (Th1) and Th2 cytokine/growth factor responses to trophoblast or other antigens are proposed to be involved in pregnancy loss and success, respectively. According to this alloimmune theory, decidual immune and inflammatory cells secrete predominantly either Th1 or Th2 cell cytokines in response to the conceptus or other antigens. The Th1 cytokines tumour necrosis factor (TNF) and gamma-interferon are reported to affect many reproductive processes adversely, and the Th1 initiating cytokine interleukin 12 has been found in the decidua of aborting women with Th1 immunity to trophoblast. TNF polymorphisms or genes in linkage disequilibrium with TNF have also been associated with recurrent abortion in women with Th1 immunity to trophoblast. Further investigations are needed to define further the immunological mechanisms involved in pregnancy loss, so that effective therapies can be designed and properly studied.

Progesterone inhibits in-vitro embryotoxic Th1 cytokine production to trophoblast in women with recurrent pregnancy loss

A dichotomous T-helper 1 (Th1) versus T-helper 2 (Th2) cytokine response to trophoblast has been proposed to mediate reproductive failure and success, respectively. Progesterone has immunosuppressive properties. In this study, peripheral blood mononuclear cells from women with and without unexplained recurrent pregnancy loss who had and did not have evidence of embryotoxic, Th1 immunity to trophoblast were cultured with progesterone (10(-5) mol/l) or interleukin (IL)-10 (1500 pg/ml) to determine whether these agents were capable of inhibiting embryotoxic, Th1 immunity to trophoblast. The effects of progesterone on Th2 cytokines and transforming growth factor (TGF)-beta secretion were also assessed. Progesterone was found to specifically block Th1 immunity to trophoblast, as was IL-10. Progesterone also appeared to upregulate TGF-beta secretion in response to trophoblast but had no effect on Th2 cytokine secretion. Our data suggest that assaying Th1 cytokines in supernatants of peripheral blood mononuclear cells cultured with a protein extract from trophoblast may identify individuals more likely to benefit from potentially immunosuppressive doses of progesterone. An appropriately designed clinical trial is needed to determine whether therapies modifying Th1 cytokine secretion in response to trophoblast are useful in the clinical management of recurrent pregnancy loss in women producing these cytokines in response to reproductive antigen stimulation.

Immunodystrophism: Evidence for a Novel Alloimmune Hypothesis for Recurrent Pregnancy Loss Involving Th1-Type Immunity to Trophoblast

Pregnancy loss is the most common complication of pregnancy. Recurrent pregnancy loss occurs in approximately 1% of pregnant women. Many immunologic theories have been proposed but have not withstood rigorous analysis. A novel alloimmune hypothesis involving T helper (Th) 1-type immunity to trophoblast is the latest theory proposed for recurrent pregnancy loss. The basic hypothesis is, in the decidua there are myriad of antigen presenting cells and other immune response cells. In response to trophoblast invasion, these cells may become activated. A by-product of this activation is the secretion by these cells of either a predominant Th1 or Th2 cytokine profile. In cases where a Th1 cytokine profile predominates, chiefly, interferon-gamma, tumor necrosis factor, or interleukin-12, these cytokines may directly or indirectly be detrimental to early placental cell differentiation and growth and toxic to embryo development. Further evidence for this novel hypothesis comes from recent findings of a genetic predisposition for a vigorous Th1 cytokine response in these women due to a polymorphism in the IL1B promoter region. Further studies are needed to substantiate definitive causative links between Th1-immunity to trophoblast and recurrent pregnancy loss. Clinical trials are also needed to determine the best therapy for this disorder.

Look before you leap: stratify before you standardize

This paper presents a mathematical model to show the conditions in which age standardization can be used to summarize age-specific rates for comparison purposes over calendar time. It shows that the conditions for valid comparison depend on the type of measure used for comparison, that is, difference, ratio, or percent change. If the measure for comparison is a difference of the standardized rates at two time points, then the age-specific rates need to maintain a constant rate difference over time for the comparison to be valid. If the measure for comparison is a ratio or percent change of the standardized rates at two time points, then the age-specific rates need to maintain a constant rate ratio over time for the comparison to be valid. Since in reality, as shown by our Canadian empirical data, age-specific rates do not always maintain a consistent pattern over time, it is recommended that one should always stratify the data to look at patterns of age-specific rates before applying age standardization.

Lifestyle modifications to prevent and control hypertension. 1. Methods and an overview of the Canadian recommendations. Canadian Hypertension Society, Canadian Coalition for High Blood Pressure Prevention and Control, Laboratory Centre for Disease Control at Health Canada, Heart and Stroke Foundation of Canada

OBJECTIVE

To provide updated, evidence-based recommendations for health care professionals on lifestyle changes to prevent and control hypertension in otherwise healthy adults (except pregnant women).

OPTIONS

For people at risk for hypertension, there are a number of lifestyle options that may avert the condition--maintaining a healthy body weight, moderating consumption of alcohol, exercising, reducing sodium intake, altering intake of calcium, magnesium and potassium, and reducing stress. Following these options will maintain or reduce the risk of hypertension. For people who already have hypertension, the options for controlling the condition are lifestyle modification, antihypertensive medications or a combination of these options; with no treatment, these people remain at risk for the complications of hypertension.

OUTCOMES

The health outcomes considered were changes in blood pressure and in morbidity and mortality rates. Because of insufficient evidence, no economic outcomes were considered.

EVIDENCE

A MEDLINE search was conducted for the period January 1996 to September 1996 for each of the interventions studied. Reference lists were scanned, experts were polled, and the personal files of the authors were used to identify other studies. All relevant articles were reviewed, classified according to study design and graded according to level of evidence.

VALUES

A high value was placed on the avoidance of cardiovascular morbidity and premature death caused by untreated hypertension.

BENEFITS, HARMS AND COSTS

Lifestyle modification by means of weight loss (or maintenance of healthy body weight), regular exercise and low alcohol consumption will reduce the blood pressure of appropriately selected normotensive and hypertensive people. Sodium restriction and stress management will reduce the blood pressure of appropriately selected hypertensive patients. The side effects of these therapies are few, and the indirect benefits are well known. There are certainly costs associated with lifestyle modification, but they were not measured in the studies reviewed. Supplementing the diet with potassium, calcium and magnesium has not been associated with a clinically important reduction in blood pressure in people consuming a healthy diet.

RECOMMENDATIONS

(1) It is recommended that health care professionals determine the body mass index (weight in kilograms/[height in metres]2) and alcohol consumption of all adult patients and assess sodium consumption and stress levels in all hypertensive patients. (2) To reduce blood pressure in the population at large, it is recommended that Canadians attain and maintain a healthy body mass index. For those who choose to drink alcohol intake should be limited to 2 or fewer standard drinks per day (maximum of 14/week for men and 9/week for women). Adults should exercise regularly. (3) To reduce blood pressure in hypertensive patients, individualized therapy is recommended. This therapy should emphasize weight loss for overweight patients, abstinence from or moderation in alcohol intake, regular exercise, restriction of sodium intake and, in appropriate circumstances, individualized cognitive behaviour modification to reduce the negative effects of stress.

VALIDATION

The recommendations were reviewed by all of the sponsoring organizations and by participants in a satellite symposium of the fourth international Conference on Preventive Cardiology. They are similar to those of the World Hypertension League and the Joint National committee, with the exception of the recommendations on stress management, which are based on new information. They have not been clinically tested.

SPONSORS

The Canadian Hypertension Society, the Canadian Coalition for High Blood Pressure Prevention and Control, the Laboratory Centre for Disease Control at health Canada, and the Heart and Stroke Foundation of Canada.

The 1996 and 1997 National survey of physician asthma management practices: background and study methodology

OBJECTIVES

To collect national baseline information on asthma management practices by physicians, and to compare these practices with the recommendations of the Canadian Asthma Consensus Conference ('the guidelines').

DESIGN

Cross-sectional survey of representative samples of physicians in Canada in late 1996 and early 1997.

POPULATION STUDIED

Five specialty types of physicians who manage asthma patients: respirology, pediatrics, internal medicine, allergy and clinical immunology, and general practice and family medicine. Stratified sampling by province and specialty was used to select physicians for the study. Weighting was used in the analysis to generalize the results to the national level for the five specialty groups of physicians.

METHOD

Mailed questionnaire, self-administered by the respondent; three mailings of the questionnaires were used to increase the response rate.

MAIN RESULTS

The frequency with which each of the five specialty types chose specific asthma management choices was determined, using weighted percentages representative of the specialty groups on a national basis. ANOVA determined the statistically significant differences among the five specialties in choosing particular asthma management actions. Then, logistic regression was used to calculate the odds ratios showing an association between the characteristics of the physician respondents and specific asthma management choices that they made in the survey.

CONCLUSIONS

The data analysis demonstrated significant variations among physicians in asthma management practices, according to specialty type and other characteristics. The initial report was released in April 1998, and manuscripts for journal submissions are being prepared.

Classification of the first web space free flap of the foot and its applications in reconstruction of the hand

Owing to its unique anatomic arterial supply and dual nerve innervation, the first web space of the foot can be used to harvest various sizes and shapes of flaps, which the authors have classified into four types according to their usage in hand reconstruction. This in turn depends on the site, shape, and size of the soft-tissue defect in the hand. Web skin flaps (n = 8) were used in prevention of contracture in the first web space and for proximal finger reconstruction. Two-island skin flaps (n = 4) were used to resurface the pulp defect in two adjacent fingers. In severe adduction contracture of the first web space, fill-up web flaps (n = 10) were used to replace the volume defect after a release procedure in the hand. Adjuvant web flaps (n = 9) were used in wrap-around procedures, in dorsalis pedis flap transfer, and in vascularized joint transfer to supplement the main flaps and to restore sensation in the reconstructed area. In the past 10 years up to February of 1998, a total of 31 patients with soft-tissue defects in the hand and fingers were reconstructed using the web space free flap with flap survival rate of 100 percent. The mean static 2-point discrimination was 8.5 (7.2 to 10) mm, and the mean first web angle was 86 degrees. The advantage of the first web space flap from the foot is that it can easily be harvested to match various sizes and shapes of defects in the hand and fingers. In addition, because of the anatomic similarity in contour, thickness, texture, and nerve innervation with the hand, the sensory restoration is excellent with minimal morbidity at the donor site. By classifying the flaps into four types according to various sizes, shapes, and the site from which the flap are harvested, clinical usefulness in various types of hand and finger reconstruction was confirmed.

Comparison of methods of point estimation in occupational epidemiologic studies

Two common study designs of occupational epidemiologic studies are cohort mortality studies, which use the population at risk as a denominator, and proportionate mortality studies, which use the total number of events as a denominator. This study compared the various methods of point estimation for cohort mortality studies, i.e., RR (risk ratio), OR (odds ratio) and SMR (standardized mortality ratio), and those for proportionate mortality studies, i.e., PRR (proportionate risk ratio), POR (proportionate odds ratio) and PMR (proportionate mortality ratio). This study was based on a real dataset of all workers in Metropolitan Toronto, Canada, who applied for compensation for various types of injuries or diseases from the Workers' Compensation Board in 1980. Results showed that within the cohort mortality or proportionate mortality study designs, OR (or POR) in all cases gave the least conservative estimates (farthest away from the null value), while SMR (or PMR) gave the most conservative estimates. The empirical differences between the point estimators were generally small. Our results showed that between study designs the corresponding point estimators were poorly correlated. In addition, this empirical study indicated that the use of the mortality odds ratio did not improve the proportionate mortality study very much in terms of generating results similar to the risk ratio from the cohort mortality design. We drew two conclusions: first, the point estimators within each study design can generally be a good alternative to one another; and second, proportionate mortality studies are not a good approximation for cohort mortality studies.

Slopes of a receiver operating characteristic curve and likelihood ratios for a diagnostic test

This paper clarifies two important concepts in clinical epidemiology: the slope of a receiver operating characteristic (ROC) curve and the likelihood ratio. It points out that there are three types of slopes in an ROC curve--the tangent at a point on the curve, the slope between the origin and a point on the curve, and the slope between two points on the curve. It also points out that there are three types of likelihood ratios that can be defined for a diagnostic test that produces results on a continuous scale--the likelihood ratio for a particular single test value, the likelihood ratio for a positive test result, and the likelihood ratio for a test result in a particular level or category. It further illustrates mathematically and empirically the following three relations between these various definitions of slopes and likelihood ratios: 1) the tangent at a point on the ROC curve corresponds to the likelihood ratio for a single test value represented by that point; 2) the slope between the origin and a point on the curve corresponds to the positive likelihood ratio using the point as a criterion for positivity; and 3) the slope between two points on the curve corresponds to the likelihood ratio for a test result in a defined level bounded by the two points. The likelihood ratio for a single test value is considered an important parameter for evaluating diagnostic tests, but it is not easily estimable directly from laboratory data because of limited sample size. However, by using ROC analysis, the likelihood ratio for a single test value can be easily measured from the tangent. It is suggested that existing ROC analysis software be revised to provide estimates for tangents at various points on the ROC curve.

Estimating the economic costs of the abuse of tobacco, alcohol and illicit drugs: a review of methodologies and Canadian data sources

The study of economic costs of substance abuse, namely, abuse of tobacco, alcohol and illicit drugs, can provide important information for setting good public health policies. This review paper provides a list of previous cost studies of substance abuse, compares the cost categories considered by various methodologies and describes an inventory of data sources for obtaining relevant information for cost studies. Investigators will find this paper useful as an introduction to the literature in this area, for designing a list of cost categories to consider in a particular study and for identifying relevant data sources.

Perspectives on epidemiologic surveillance in the 21st century

This paper describes the importance of epidemiologic surveillance as a systematic, ongoing and population-based system for early warning and program development in the 21st century. Such a system routinely collects data on three classes of indicators (health outcomes, risk factors and intervention strategies) to set up both an early warning system (to identify associations and make predictions on health outcomes) and a program development system (to assess the need for intervention strategies, to plan and implement such strategies and to assess their effectiveness). A comprehensive surveillance system must be systematic (evidence-based selection of indicators, not hypothesis-driven), ongoing (continuous data collection, including repeated surveys) and population-based (whole population, or representative samples of the population). Such a system need not be developed from scratch, but can be based on linkage of existing databases and collection of additional information for identified data gaps. The initial steps for selecting indicators and creating a prototype framework for a comprehensive surveillance system are proposed to stimulate further discussion. It is suggested that surveillance systems should be more widely used in public health.

Reducing variability in treatment decision-making: effectiveness of educating clinicians about uncertainty

The objective of this study was to investigate whether or not education about the concept of uncertainty reduced variability in treatment decision-making. Three small groups of dentists in North York, Canada were asked to make restorative treatment decisions about simulated bitewing radiographs. They subsequently took part in a seminar about variations in perception and judgement and were given explanations of sensitivity, specificity and receiver operating characteristic (ROC) curve analysis. A repeat reading of the radiographs was then performed by both test and control groups. Results indicated that the intervention increased the accuracy, and decreased the variability of dentists' restorative treatment decisions. Kappa statistics were 0.33, 0.34 and 0.31 before the seminar, and 0.40, 0.43 and 0.41 after the seminar. Standard errors for kappas were 0.06, 0.05 and 0.05 before the seminar, and 0.02, 0.02 and 0.05 after the seminar. The area under the ROC curve was 0.7136 before the seminar and 0.7835 after the seminar. The data demonstrate that the dentists' decisions were less variable and more accurate following the educative intervention. This study suggests that there is potential for improving consistency and accuracy in clinical decision-making through education in probabilistic reasoning.

Causal modeling to estimate sensitivity and specificity of a test when prevalence changes

The objective of this paper is to demonstrate, by causal modeling, whether the sensitivity and specificity of a test are constant, or whether they change with prevalence. I use three assumptions, diagnostic, predictive, and correlational, in three sets of mathematical models. A diagnostic test measures an outcome of a disease and is based on the assumption that the "gold standard" result indicates a disease state that causes a test result. A predictive test measures a risk factor for a disease and is based on the assumption that the test result indicates a risk factor that causes a disease state. A correlational test measures a condition which is an outcome of an underlying causal risk factor for a disease and is based on the assumption that the disease and the test result are noncausally related. I find that sensitivity and specificity are constant for diagnostic tests but change with prevalence for predictive and correlational tests. I present equations to show the effects on various test performance indices when prevalence changes. Different equations must be used to estimate the sensitivity, specificity, and other test performance indicators for various types of tests that are under different causal assumptions.

Recording, notification, compilation, and classification of statistics of occupational accidents and diseases: the Thai experience

An International Labour Organization (ILO) project was conducted in July and August 1995 in Thailand to assist with the development of an information system on occupational accidents and diseases for the Workmen's Compensation Fund (WCF). The WCF provides cash benefits and medical care to insured workers who suffer employment injuries. The project included literature research based on the facilities of the ILO in Bangkok, and those of the Thai government, and a thorough review of the ILO Code of Practice (the Code) on recording and notification of occupational accidents and diseases, and of other international recommendations on statistics of occupational accidents and diseases. A comparative study of various notification systems of occupational accidents and diseases in Australia, Canada, the Philippines, Sweden, Thailand, and the United States was conducted. The project also included fact-finding sessions among various information suppliers and users in Thailand. The Thai notification form for collecting data for the database was redesigned and pretested. Results of the project indicated that the Code is appropriate for the recording and notification of occupational accidents and diseases in Thailand. In addition, a number of information requirements, which were included in the notification systems in the countries studied but not listed in the Code, were found to be useful for the database. A list of the baseline variables to be included in the proposed database was developed, the notification form was redesigned, and coding schemes for the information collected on the redesigned form were constructed on the basis of international standard classification systems for economic activity, employment status, occupation, nature of injury, occupational disease, body part, type of accident, and agency. A number of mechanisms were suggested for cross-checking the accuracy of data in the database. Based on the review of the Code and other international recommendations on statistical reporting, a list of baseline statistics was formulated for inclusion in the WCF annual report. Lastly, some suggestions for future statistical analysis of the database were given.

Risk assessment in dentistry: health risks of dental amalgam revisited

This paper reviews the basic methodology of risk assessment and describes the four steps involved, namely hazard identification, hazard evaluation, exposure evaluation, and risk estimation. The risk posed by the release of mercury vapor from dental amalgam restorations is used as an example to demonstrate the advantages and limitations of this process.

Patterns and risk factors for sprains and strain in Ontario, Canada 1990: an analysis of the Workplace Health and Safety Agency data base

This study presents the results of analyses performed to generate hypotheses concerning the general patterns of risk factors for occupational sprains and strains, using Ontario workers' compensation data housed in the Workplace Health and Safety Agency (WHSA) data base. Historically, the largest percentage of lost-time injuries in Ontario, Canada, have been sprains and strains. In 1990, there were 171,047 compensated lost-time injuries with a known nature of injury, of which 50.43% were sprains and strains. From cross-tabulations, a number of statistics such as odds ratios (ORs), 95% confidence intervals, P values, attributable risks and number of injuries attributable, were calculated. Results indicate that occupational sprains and strains are related to the time of the day and, in particular, time into the workshift. They occur more frequently than expected (based on the occurrence of non-sprain and non-strain injuries) in the morning hours and in the first 4 hours of the workshift. They are not found to be related to the starting or ending time or the length of the workshift. They occur more frequently than expected during the early part of a week, especially on Mondays, and the early part of a year (January to May). With respect to age, workers 30 to 59 years old have an increased risk of sprains and strains, whereas workers less than 30 years of age, or 60 or more years of age, have a decreased risk. Workers who are not single, and female workers, have a higher risk of sprains and strains than expected. With respect to occupations, nurses and truckers have a higher-than-expected risk. A number of work environments and activities, such as overexertion, bodily reaction from involuntary motions, running and stretching, and slippery surfaces, are associated with a high risk of occurrence of sprains and strains. These results suggest that significant reduction in the number of occupational sprains and strains could be achieved by targeting prevention programs to reduce excess risks encountered in the first 4 hours of the workshift, on Mondays, and during the first 5 months of the year, and by workers 30 to 59 years of age, female workers, and nurses and truck drivers. It is estimated that, with proper interventions to avoid sprains and strains, a large percentage of sprain and strain injuries could be avoided each year: ie 82.49% of injuries due to bodily reaction from involuntary motions, 89.43% of overexertions in lifting objects, 84.64% of running, stretching, and related injuries, and 76.64% of injuries resulting from loss of balance on slippery surfaces. This study uses an internal comparison, ie comparing the risk of sprains and strains to the risk of all other injuries for various risk categories of interest. As a result, an increased OR may mean an increased risk of sprains and strains, or it may mean a decreased risk of all other injuries for a particular risk category. There are also limitations in the use of workers' compensation data base for epidemiologic studies. Therefore, findings in this study are only suggestive for further investigations and should await confirmations before prevention programs are designed.

Health and social costs of tobacco use in Ontario, Canada, 1979 and 1988

STUDY OBJECTIVE

This study aimed to estimate the health and social costs of tobacco use in Ontario, Canada.

DESIGN

This was a cost-benefit analysis based on cross sectional data in 1988, stratified by age and sex, using an attributable risk model. The total cost of the consequences of tobacco use in the society included those costs attributed to extra deaths, disability, hospitalisation, physician visits, and fire losses, from tobacco use.

PARTICIPANTS

The general population of Ontario, Canada.

MAIN RESULTS

The total cost of tobacco use in Ontario, Canada in 1988 was estimated to be $3.623 billion--$721 million more than the total customer expenditure on tobacco products. Tobacco use was also found to be responsible for 14% of all adult deaths, 5% of all adult disability days, 14% of all days of hospitalisation, and 3% of all physician visits. Compared with previous results for Ontario (1979) the cost of the consequences of tobacco use had increased by about 25% and consumer expenditure by about 35% over the period, while the excess of consequences over expenditure fell slightly by about 3%.

CONCLUSIONS

The annual excess of the social costs of tobacco use over total consumer expenditure is staggering. It is suggested that similar cost-benefit analysis of smoking be carried out at regular intervals to monitor smoking trends in the society, to estimate health and social costs, and to provide information for the setting of targets for tobacco control and healthy public policies.

A nested case-control study on alcohol drinking, tobacco smoking, and cancer

A nested case-control study was conducted to investigate the effect of alcohol consumption and tobacco smoking on cancers of various sites. The study population was based on 887 cases and 1774 controls, selected from a cohort of 17,200 male participants of a gastric mass survey in 1984, who were followed up for 9 years by the Chiba Cancer Registry, Japan. The odds ratio (OR) of colon cancer was significantly elevated in alcohol drinkers of one cup of sake-equivalent (27 ml ethanol) per day (OR = 3.5), and three cups of sake-equivalents per day (OR = 3.2) compared with nondrinkers, but its dose-response was not clear since two cups of sake-equivalents per day had an OR of 1.9, which was nonsignificant. Cancer risk elevation was especially predominant in the proximal colon, again showing no dose-response: OR = 30.7 for one cup of sake-equivalent per day, OR = 12.4 for two or more cups per day. Lung cancer showed a dose-response relationship with alcohol consumption, independent of tobacco smoking. A synergistic effect of alcohol intake and tobacco smoking was observed for upper aerodigestive tract and bladder cancer. Both alcohol drinking and tobacco smoking were found not to be associated with stomach cancer.

Cancer mortality among Chinese migrants: a review

BACKGROUND

Epidemiological studies of cancer among migrant groups are beneficial in that they can provide insight into genetic and environmental factors in disease aetiology. Seven studies in the epidemiological literature have examined cancer mortality in migrants from China; methodological features and findings, which display remarkable consistencies between studies, are reviewed here.

METHODS

Papers were included that compare site-specific cancer mortality patterns in first and second generation migrants to the experience in the host regions using vital statistics and census data. Rates had to be standardized either indirectly (using age-specific rates from the host regions) or directly (using a standard age structure) and standardized mortality ratios (SMR) or rate ratios (RR) were calculated.

RESULTS

Migrant males had overall mortality from cancer that was often in significant excess compared to the host experience; results for females (for overall cancer) were equivocal. Both sexes had large and significant excess mortality from nasopharyngeal and liver cancer; SMR and RR were also consistently elevated for cancers of the stomach and oesophagus. There was notable attenuation in the high risk at these four sites in the second generation. All studies reported pronounced and significant reduced risk for prostatic cancer and female breast cancer, with little or no increase in mortality in the second generation. The SMR and RR also tended to be below unity for brain, bladder and kidney cancer.

CONCLUSIONS

The results of this review indicate that cancer risk at several sites among Chinese migrants appears to be in transition, and that these findings are consistent across studies.

Application of urinary mutagen testing to detect workplace hazardous exposure and bladder cancer

The objectives of this biochemical epidemiologic case-control study were to evaluate urinary mutagen testing for occupational exposure assessment, and for possible screening for bladder cancer in the workplace. Thirty-seven patients (19 bladder cancer cases and 18 controls) completed a questionnaire. Two urine samples, i.e. a work sample taken while at work, and a home sample, were requested from each patient. Twenty-six patients (17 cases and 9 controls) gave a total of 47 24-h urine samples for mutagenicity testing by the Ames test. A positive Ames test was found to be associated significantly with current occupation with hazardous exposure (odds ratio = 3.7, 95%CI 1.1-12.9), and non-significantly with bladder cancer (odds ratio = 1.8, 95%CI 0.5-7.1). Our results show that the urinary Ames test has the potential of being used as a surveillance for current workplace hazardous exposure (sensitivity = 52%, specificity = 77%, positive predictive value = 72%, negative predictive value = 59%, positive likelihood ratio = 2.3), but not as a screening test for bladder cancer cases (sensitivity = 42%, specificity = 71%, positive predictive value = 3%, negative predictive value = 98%, positive likelihood ratio = 1.5).

A comprehensive evaluation of the 1993 city of Toronto smoking by-laws

Effective January 1, 1993, the City of Toronto's two smoking by-laws--one regarding workplaces and another regarding public places--were replaced and amended respectively. Smoking is now prohibited in all workplaces (unless in a designated smoking area), and in at least 50% of eating areas in restaurants. Through a workplace telephone survey and restaurant inspection records, the implementation and enforcement of the by-laws were evaluated. Eighty-three per cent of the workplaces were completely smoke-free and 7% had restricted smoking to a designated area. A majority (76%) of the managers and owners were in favour of regulatory controls on smoking in workplaces. Eighty-six per cent of restaurants complied with requirements for a minimum 50% smoke-free area and signage, and nearly 4% of the sampled restaurants banned smoking throughout the entire premises even though this is not currently required.

Use of surnames to identify individuals of Chinese ancestry

The objectives of this study were to develop and test surname lists for identifying Chinese ancestry. The Ontario all-cause mortality database for the period 1982-1989 was randomly split into source and test data sets. Frequencies by birthplace were compiled for each surname in the source data set, by sex, and the surnames were weighted based on their positive likelihood ratios. Lists of Chinese surnames were then assembled based on varying cutoff levels, and screening performance indicators for each list were calculated, including sensitivity, specificity, positive and negative predictive values, post-test odds, positive likelihood ratio, and yield. The internally generated lists were evaluated in the test data set. Results indicated that surnames have a good potential to identify individuals of Chinese origin. In the source data set, at a cutoff level of 100 for males (217 surnames) and females (210 surnames), both sensitivity and the positive predictive value of the surname lists for males and females were very high, above 80%, and the positive likelihood ratio was above 600. In the test data set and using the same surname lists, the sensitivity, positive predictive value, and positive likelihood ratio remained at a high level: 73%, 81%, and 603, respectively, for males; and 73%, 84%, and 772, respectively, for females. Various scenarios and their methodological implications are discussed.

Characterization of a peroxidase in excretory-secretory product of adult Paragonimus westermani

When activity of peroxidase in adult Paragonimus westermani was monitored using o-dianisidine and H2O2 as substrates, its specific activity was 1.5 times higher in excretory-secretory product (ESP) than in crude extract. The enzyme was purified by two purification steps of Sephacryl S-300 Superfine gel permeation and DEAE-Trisacryl M anion exchange chromatographies. Its activity increased 16.9 fold with 32.3% recovery. The enzyme was inhibited totally by 1 millimoles of dithiothreitol (DTT), 2-mercaptoethanol and azide. Molecular mass was 16 kDa in reducing SDS-polyacrylamide gel electrophoresis (PAGE) or 19 kDa in TSK-Blue gel filtration high performance liquid chromatography (HPLC), respectively. Special staining for peroxidase by diaminobenzidine on SDS-PAGE confirmed the activity. The peroxidase was less reactive to a paragonimiasis serum when observed by SDS-PAGE/immunoblot. In addition, specific activities of superoxide dismutase (SOD) and catalase were also identified in the ESP. High activities of these antioxidant enzymes in ESP indicate that they are parts of defense mechanisms against reactive oxygen intermediates from host.

Definition, sources, magnitude, effect modifiers, and strategies of reduction of the healthy worker effect

This article summarizes, compares, and contrasts the definition, sources, magnitude, effect modifiers, and strategies of reduction of the healthy worker effect (HWE), based on the opinion expressed in the papers of nine contributors who responded to the request of the Industrial Disease Standards Panel (IDSP), Ontario, Canada. It provides an insight into the complex issues relating to the HWE. In addition, the catalog of 15 strategies to reduce the HWE is deemed to be useful for investigators in occupational epidemiology.