Lung dust analysis in the assessment of past exposure of man-made mineral fibre workers

In the cohort of American MMMF workers reported by ENTERLINE et al. [Ann. occup. Hyg. 31, 625-656 (1987)] autopsies were recorded in 652 (13.5%) of 4840 deaths. Lung tissue samples were sought from all pathologists and obtained in 145 (22.2%), together with similar samples from 124 matched referents. Lung fibre counts by phase contrast microscopy were 60% higher (P less than 0.05) in workers than referents. Electron microscopy (ATEM) also showed more fibres of all kinds--MMMF, asbestos and other--but no convincing excess of any one type. Lung samples of only 26% of workers contained any MMMF, almost all siliceous in nature and in low concentration. There were too few cases of lung cancer (19) for any useful conclusion; however, in the plant with the highest lung cancer SMR (200), and a probable mesothelioma, amosite at greater than 1.0 fibres per micrograms (f micrograms-1) was found in four of six workers but in none of their matched referents. Although our findings contribute little to the interpretation of the results obtained by ENTERLINE et al. they indicate the potential value of tissue analyses in monitoring epidemiological studies of MMMF exposure.

Opportunistic infections with Strongyloides stercoralis in renal transplantation

Opportunistic infections with the nematode Strongyloides stercoralis occur most often in patients with impaired T lymphocyte function, including recipients of renal allografts. Occult intestinal infection can remain quiescent for more than 30 years, becoming apparent only after the initiation of immunosuppression. Pulmonary and gastrointestinal symptoms predominant as initial clinical manifestations in patients with strongyloides hyperinfection or dissemination. Although thiabendazole remains the treatment of choice for all forms of strongyloidiasis, the duration of therapy must be individualized on the basis of frequent examinations of both stool and sputum. Transplantation centers drawing patients from areas with endemic Strongyloides should evaluate potential recipients closely for occult strongyloides infection prior to initiating immunosuppressive therapy. Empiric therapy with thiabendazole should be considered for renal allograft recipients with unexplained eosinophilia and a history of travel or residence in an area with endemic Strongyloides. Prophylactic monthly administration of thiabendazole in immunocompromised patients who have survived strongyloides hyperinfection or dissemination can prevent reinfection.

UNOS: 1989

This paper provides the current data which has been accrued by the UNOS National Scientific Registry as a result of the mandatory sharing of 6-antigen matched kidneys. The 6-month graft survival does not show, as yet, any benefit for first grafts (N = 72), but does show substantial benefit for repeat grafts (N = 25). No penalty from sharing could be demonstrated since graft survival for local and shared organs was the same. The rationale for two new UNOS policies are discussed: (1) mandatory sharing of phenotypically identical kidneys, (2) the "payback system" for shared kidneys. Finally, some personal comments of the author regarding the importance of the National Organ Procurement and Transplant Network are recorded.

An outbreak of toxoplasmosis in pregnant women in northern Québec

An ongoing screening program for toxoplasmosis identified a cluster of four women from northern Québec who, over a 4-month period, seroconverted during their pregnancy. An epidemiologic investigation was carried out in an attempt to identify the source of this infection. All potential risk factors were assessed by a questionnaire administered to 22 Inuit women who had delivered babies in the previous year. Seroconversion was significantly associated with skinning of animals for fur (P = .015) and frequent consumption of caribou meat (P = .034). Compared to seronegative women, women who were seropositive were more than four times more likely to have eaten dried seal meat (P = .067), more than six times more likely to have eaten seal liver (P = .064), and more than eight times more likely to have consumed raw caribou meat more than once per week (P = .054). These observations have contributed to the development of guidelines for the prevention of toxoplasmosis in seronegative pregnant women in this arctic region.

Occupational health at the London School of Hygiene & Tropical Medicine

The London School of Hygiene and Tropical Medicine, founded in 1929 to study all aspects of public health, set up an occupational health unit in 1956 funded by the Rockefeller Foundation. With financial aid from the Trades Union Congress it expanded into an institute with an information and advisory service. Employers and trade unions sought advice on health problems which led to research projects and enriched teaching. Postgraduate courses in occupational medicine and hygiene attracted many students from all over the world. If the threat to close the institute takes place it will deprive the western world of a major centre for teaching and research in occupational health.

Human leukocyte antigen and leprosy: study in northern Louisiana and review

We examined the relationship of human leukocyte antigen (HLA) phenotype to leprosy in six sporadic cases in northern Louisiana and in the world literature through pooling of the results of several studies. We found that HLA antigens DR2 and DQwl were associated with leprosy in the six cases in northern Louisiana (relative risks, 4.57 for DR2 and 4.53 for DQwl), but the results are not statistically significant. We pooled the Louisiana study and other population studies of HLA and leprosy. The results of the pooling show DR2 and DQwl to be associated with leprosy (relative risks, 2.65 for DR2 and 2.73 for DQwl), and these associations are highly statistically significant (P less than 1 x 10(-8) for DR2 and P = 3.6 x 10(-8) for DQwl). Further, we pooled studies of lepromatous leprosy patients vs. controls and studies of tuberculoid leprosy patients vs. controls and found that DR2 and DQwl are associated with both the lepromatous and the tuberculoid forms of leprosy and that these associations are statistically significant. We consider the associations of DR2 and DQwl in these population studies to be evidence for an HLA-associated genetic influence on susceptibility to leprosy.

Clinical and epidemiologic features of mumps meningoencephalitis and possible vaccine-related disease

All cases of mumps meningoencephalitis diagnosed at our institution during the past 15 years were reviewed. There were 24 cases, 16 between 1973 and 1977, 3 between 1978 and 1985 and 5 in 1986 to 1988. Four of the recent cases occurred 19 to 26 days after receipt of a new mumps vaccine (Urabe Am 9 strain) released in Canada in 1986. The remaining 20 cases were clustered in winter and spring. The average age was 6.2 years and the ratio of males to females was 5:1. Clinical presentations were fever (90%), vomiting (90%), meningismus (70%), headache (65%), parotitis (50%) and seizures (30%). The mean cerebrospinal fluid white blood cell count was 513/mm3 (lymphocyte predominance); 55% of patients had a cerebrospinal fluid protein level of greater than 0.4 g/liter, and the cerebrospinal fluid:blood glucose ratio was greater than 0.4 in all. Two patients had adverse sequelae. The clinical and laboratory features of these cases were not significantly different from the vaccine-associated cases.

Valvular xenografts in the inferior vena cava

The unsolved problem of valvular incompetence is a common denominator to chronic venous insufficiency. Cardiac experience with tissue valves suggests the potential for their use in more peripheral locations. The current initial work evaluated 22 valvular xenografts placed in the inferior vena cavas of 22 dogs. Patency extended to 28 months in 12 valves. There was a plausible explanation for failure in 8 of the 10 unsuccessful units. Patent valves functioned with minimal pressure gradients at moderate flow with no evidence of pulmonary emboli. Retrograde valvulograms showed acceptable functional competence in six of eight units examined despite autopsy evidence of leaflet fibrosis and anatomic incompetence. The study establishes the feasibility of long-term patency of valvular xenografts in the inferior vena cava, but also raises questions concerning design requirements for prosthetic venous valves.

Issues related to race in transplantation

It would be possible to refute any comment or finding that suggests a transplantation problem intrinsic to race with any data available today. Reliable studies that consider education, income, access to competent care, and ability to understand and interpret instructions are badly needed. Those of us who have cared for large numbers of the poor commonly acquire a great respect for the almost noble way many face severe or chronic illnesses. Many times, these people approach self-sacrifice in order to protect or provide for their families or dependents. We need to place less effort in considering if a person is black, Scot, Mexican, Arabic, and so on and more effort providing good education and access to economic independence to the underprivileged in our society. Thus, I end as I started. There are no transplantation issues related to race. There are only transplantation issues related to human beings.

Fathers' occupation and pregnancy outcome

Findings from a survey of 56,067 women in Montreal on maternal occupation and pregnancy outcome have been reported. Paternal occupation recorded in the same survey was analysed for spontaneous abortion in 24 occupational groups retaining the six main sectors of maternal occupation and allowing, by means of logistic regression, for seven potentially confounding variables. In only one of the 24 fathers' occupational groups was there a statistically significant excess of spontaneous abortions--mechanics, repairers, and certain assemblers (O/E = 1.10, 90% CI = 1.02-1.20); subdivision of this group suggested that this excess was mainly attributable to the large group of motor vehicle mechanics (O/E = 1.17). No significant excess of known chromosomally determined defects was found in any of the 24 occupational groups. An association of developmental defects was found with food and beverage processing (18 defects observed compared with 8.02 expected; p less than 0.05); however, there was no specificity in type of food, beverage, or congenital defect, and no obvious explanatory mechanism.

Mesothelioma and asbestos fiber type. Evidence from lung tissue analyses

Lung tissue samples from 78 cases from autopsy of mesothelioma in Canada, 1980 through 1984, and from matched referents were examined by optical and analytical transmission electron microscopic study. Concentrations of amosite, crocidolite, and tremolite fibers, and of typical asbestos bodies discriminated sharply between cases and referents. The distributions of chrysotile and anthophyllite/talc fibers and of all other natural and man-made inorganic fibers (greater than or equal to 8 microns) in the two series were quite similar. Relative risk was related to the concentration of long (greater than or equal to 8 microns) amphibole fibers with no additional information provided by shorter fibers. The proportion of long fibers was much higher for amphiboles than chrysotile and, except for chrysotile, systematically higher in cases than referents. Amphibole asbestos fibers could explain most mesothelioma cases in Canada and other inorganic fibers, including chrysotile, very few. Fibrous tremolite, contaminant of many industrial minerals including chrysotile, probably explained most cases in the Quebec mining region and perhaps 20% elsewhere.

Ficoll-Hypaque leukocyte preparations from burned patients contain activated nonlymphoid cell populations that take up thymidine

Previously, we reported that Ficoll-Hypaque-purified leukocytes from burned patients were activated in vivo, even when the mitogen response of these cells was depressed. In these patients, the SBT (endogenous blastogenesis), but not the mitogen response predicted sepsis. The current experiments were performed to clarify why the SBT is increased even when mitogen-stimulated blastogenesis is impaired. We found that neither selective lymphocyte subpopulation (OKT3, T4, T8), nor macrophage depletion returned the increased SBT to normal and that by phenotype and flow cytometric morphology, the Ficoll-Hypaque-purified leukocyte preparations of the burned patients contained fewer lymphocytes than controls (p less than 0.001). Discontinuous Percoll gradients and sheep-RBC rosetting were used to determine the relative contribution of T cells and non-T cells to the increased SBT. These studies indicated that both T cells and non-T cells were activated; however, the non-T cells were primarily responsible for the increased SBT. Thus the peripheral blood of burned patients contains a large fraction of metabolically active non-mononuclear cells that cosediment with mature lymphocytes and could result in artifactual alterations in the assessment of lymphocyte function by in vitro tests.

Respiratory cancer in chrysotile textile and mining industries: exposure inferences from lung analysis

In an attempt to explain the much greater risk of respiratory cancer at the same cumulative exposure in asbestos textile workers in Charleston, South Carolina, than in Quebec miners and millers, both exposed to chrysotile from the same source, 161 lung tissue samples taken at necropsy from dead cohort members were analysed by transmission electron microscopy. Altogether 1828 chrysotile and 3270 tremolite fibres were identified; in both cohorts tremolite predominated and fibre dimensions were closely similar. Lung fibre concentrations were analysed statistically (a) in 32 paired subjects matched for duration of employment and time from last employment to death and (b) in 136 subjects stratified by the same time variables. Both analyses indicated that the Quebec/Charleston ratios for chrysotile fibre concentration in lung tissue were even higher than the corresponding ratios of estimated exposure intensity (mpcf). After allowance for the fact that regression analyses suggested that the proportion of tremolite in dust was probably 2.5 times higher in Thetford Mines, Quebec, than in Charleston, the results from both matched pair and stratification analyses of tremolite fibre concentrations in lung were almost the same as for chrysotile. It is concluded that neither fibre dimensional differences nor errors in estimation of exposure can explain the higher risks of lung cancer observed in asbestos textile workers. The possible co-carcinogenic role of mineral oil used in the past in asbestos textile plants to control dust provides an alternative hypothesis deserving consideration.

Imported rickettsial disease: clinical and epidemiologic features

PURPOSE AND METHODS

The rickettsioses continue to constitute major health problems in many parts of the world. With increasing international travel, recognition of rickettsial diseases by physicians is becoming more important. The clinical features of four cases of rickettsial disease imported into Canada over a five-year period are presented; two patients with tick typhus (Rickettsia conorii), one patient with scrub typhus (R. tsutsugamushi), and one patient with murine typhus (R. typhi). We also present the North American data over the past 10 years from the Centers for Disease Control (CDC) (Atlanta).

RESULTS

Since 1983 in the United States, three cases of imported scrub typhus, all after travel to India, were confirmed, as well as six cases of murine typhus after travel to southeast Asia. At the CDC, 67 imported cases of tick typhus have been confirmed by indirect fluorescent antibody test since 1976; most illnesses occurred after travel to Africa.

CONCLUSION

Rickettsial diseases are underrecognized by physicians, who should consider these diagnoses in travelers returning from endemic areas. Since effective treatment is available, prompt diagnosis and treatment are important. In all cases, specific serologic confirmation should be obtained.

Child and adolescent day treatment: population profile

This paper presents the demographic and clinical data necessary to define the population of children and adolescents served in a model day treatment program. On the day of admission, patients (N = 204) and parents complete a batter of instruments designed to measure reliably characteristics of the patient's system at three levels: individual, parental, and family. Design of the assessment establishes comparisons among self-report, parent/other report, and clinician report measures at each subsystem level. Results of the CBCL, YSR, PIC, Piers-Harris, MCMI, DAS, and FES indicate moderate levels of disturbance, usually consistent with norms reported on referred or clinical populations. Patients are being treated for a wide variety of childhood disorders within systems demonstrating dysfunction at parental, marital, and familial levels.