Chrysotile asbestos in a California recreational area.

Dustfall along roads and trails being used recreationally in the Clear Creek area of San Benito County, California, located in the New Idria serpentinite, was found to be 90 percent or more chrysotile asbestos. Personal samplers worn by motorcyclists using one of the trails showed concentrations of airborne fibers ranging from 0.3 to 5.3 fibers per milliliter, according to methods prescribed for monitoring occupational exposures. The present workplace standard for brief exposures to asbestos is 10 fibers per milliliter; 5 fibers per milliliter is the proposed standard. The average total dust concentration estimated from personal samplers was approximately 20 milligrams per cubic meter of roughly 90 percent chrysotile. To our knowledge, this is the first demonstration of asbestos exposures of this magnitude, in size ranges known to be pathogenic, resulting from natural deposits not associated with mining, milling, or industrial use.

Flunisolide metabolism and dynamics of a metabolite.

Flunisolide (6 alpha-fluoro-11 beta,16 alpha,17 alpha,21-tetrahydroxypregna-1,4-diene-3,20-dione 16,17-acetonide) is a potent corticoid used clinically in topical formulations. Three men were given single 2-mg intravenous and oral doses of 14C-labeled flunisolide and plasma and urine concentrations of flunisolide and a major metabolite, 6 beta,11 beta,16 alpha,17 alpha,21-penta-hydroxypregna-1,4-diene-3,20-dione 16,17-acetonide (6 beta-OH metabolite) were determined. Oral flunisolide was metabolized rapidly and extensively to the 6 beta-OH metabolite and to conjugates; comparison in the intravenous dose kinetics suggested significant first-pass metabolism. In a separate study in 12 normal subjects, flunisolide in plasma was quantitated by radioimmunoassay (RIA); average systemic availability was 20%. The apparent volume of distribution (Vd beta) of flunisolide was large and systemic clearance and apparent oral clearance values were high. The 6 beta-OH metabolite had corticoid activities no more than 3 times that of hydrocortisone in rats as measured by thymolytic, anti-inflammatory, and adrenal-suppressive assays, whereas flunisolide had 180 to 550 times the activity of hydrocortisone. These data offer a metabolic explanation for the clinical observation that flunisolide can be administered intranasally and by inhalation in therapeutically effective doses without causing significant reduction in adrenal function.

Deaths from chronic renal disease in U.S. battery and lead production workers.

This report is based on an analysis of deaths in 4519 battery plant workers and 2300 lead production or smelter workers during the years 1947 to 1980. Causes were coded to the seventh (1955) revision of the International Classification of Diseases. There were significant excess deaths for "other hypertensive disease" (444-447) and "chronic nephritis" (592-594) in both cohorts, the standardized mortality ratios (SMRs) being 320 and 475, respectively, for the former causes and 222 and 265 for the latter. Proportionate mortality analysis, which adjusted for race, also showed elevated ratios, 241 and 388 for the former causes and 296 and 186 for the latter. Deaths from other hypertension-related diseases did not show comparable excesses. Renal cancer deaths were fewer than expected, SMRs being 41 and 74, respectively.

Epidemiologic study of vinyl chloride workers: mortality through December 31, 1972.

A population of 10,173 men, employed in 37 plants, was identified as having worked for at least one year in jobs involving probable exposure to vinyl chloride monomer (VCM) prior to January 1, 1973. Of the 9677 men whose vital status was determined, 707 were known to have died. For 699, death certificates were obtained. The standardized mortality ratio (SMR) for all causes was 89, that for all malignancies was 104. The only type of malignancy found in significant excess was in the category of malignant neoplasms of the brain and other parts of the nervous system; 12 deaths occurred where 5.9 were expected, for an adjusted SMR of 203. There were slight but inconclusive upward trends in all malignancies, and for malignancies of the respiratory tract, digestive tract, and central nervous system associated with reported levels of maximum exposure to VCM. When groups in whom less than 20 years had elapsed from the first exposure were compared with those with 20 or more elapsed years, and 25 or more elapsed years, no significantly different SMR's were detected for major primary sites of malignancy. Plans for an updated study of mortality, to include deaths in the period 1973-1979 are briefly discussed.

Combined surgery and cryotherapy for diffuse malignant melanoma of the conjunctiva.

Two patients who had refused exenteration for widespread conjunctival melanoma were treated by a combination of cryotherapy and surgical excisions. Cryotherapy was delivered only to the extensive areas of flat intraepithelial melanocytic proliferation (precancerous melanosis), while the surgical excisions were performed on the focal nodules, representing localized invasive melanoma. In our two patients, the invasive nodules measured, respectively, 1.2 and 1.5 mm in greatest thickness, placing them in a low to borderline risk group for metastasis. Repeated cryoapplicatons were required to control the widespread flat intraepithelial disease. The conjunctiva tolerated these procedures well because the substantia propria is not sacrificed as it must be in surgical conjunctivectomy, allowing comparatively normal reepithelialization to occur from adjacent zones, after the treated epithelium containing the melanocytes sloughs. No evidence of invasive melanoma (cancerous melanosis) has developed in any of the cryotreated areas of intraepithelial disease (precancerous melanosis); sequential biopsies have established that the atypical melanocytes have disappeared from the epithelium.

Cancer mortality patterns in the lead industry.

The mortality of 7,032 men employed for one or more years in lead production facilities ("smelters") or battery plants was observed over a 23-year period, 1947-1970. There were 1,267 certified deaths. Lead absorption in many members of the cohort was known to have been greatly in excess of accepted standards. The standardized mortality ratio (SMR) for all causes was 107 for smelter workers and 99 for battery plant workers. Deaths from malignant neoplasms were somewhat elevated in both groups, the SMR being 133 for smelter workers and 111 for battery plants. The excesses arose largely from tumors of the digestive organs and the respiratory system. Only three deaths are attributed to malignant renal tumors and seven to tumors of the central nervous system. The latter findings were of interest in view of the experimental production of renal tumors in rats and mice by the injection or oral administration of very large doses of lead salts, and the report by one group of investigators of gliomas in rats fed lead subacetate. Studies are continuing to characterize more fully the exposure of the above lead workers to substances other than lead. Additional follow-up of the cohort is also contemplated.

Bulk laxative efficacy of a psyllium seed hydrocolloid and of a mixture of cellulose and pectin.

The cellulose/pectin combination (C/P) investigated in this study is as efficacious as a psyllium seed product widely used as a bulk laxative. Because of its physical characteristics (whiteness, lack of flavor and odor, lack of gelling upon standing), it is easy to use as a component of baked foods, sauces, drinks, stews, and in other recipes. Given its fecal bulking equivalence to the popular psyllium-based products, C/P offers advantages to the patient who takes a bulking agent regularly because of the wide choice of methods of consumption, ensuring better compliance over long periods of time. This cellulose/pectin combination appears to be a viable alternative to the limited choice presently available to the bulk laxative user and could also be used as a plant fiber supplement whenever this is desirable.

Mortality among employees of lead battery plants and lead-producing plants, 1947-1980.

Two cohorts of male lead workers, 4 519 battery plant workers and 2 300 lead production workers, all of whom had been employed for at least one year during the period 1 January 1946 through 31 December 1970, were observed for mortality during the 34 years from 1 January 1947 through 31 December 1980. Vital status as of the closing date was determined for 94.7% of the former group and 91.6% of the latter. There were 1 718 deaths in the first cohort and 621 in the second. Mortality from all causes combined was significantly greater than expected in each cohort, the standardized mortality ratio (SMR) being 107 and 113, respectively. Among the battery plant workers the greater than expected mortality rate resulted in large part from a significant number of excess deaths from malignant neoplasms (SMR 113), other hypertensive disease (mainly renal) (SMR 320), chronic nephritis (SMR 222), and a group of ill-defined conditions (SMR 355). Among the lead production workers the pattern was similar, with a significant number of excess deaths from other hypertensive disease (SMR 475), hypertensive heart disease (SMR 203), chronic nephritis (SMR 265), and ill-defined conditions (SMR 214). There was also a significant excess of deaths from external causes (SMR 143). The SMR for total malignancies was 113, but this value was not significantly elevated at the 5% level. In neither cohort were deaths from cerebrovascular disease in significant excess, the SMR being 93 and 132, respectively. A proportionate mortality analysis showed that the excess deaths from cerebrovascular disease and from hypertensive heart disease among smelter workers were in part due to the high proportion of nonwhites in the smelter populations. The stomach, liver, and lungs were the sites responsible for most excess cancer deaths in both cohorts, but the elevated SMR values were statistically significant only for gastric and lung cancers in battery plant workers. There were no excess deaths from malignancies of the kidney, brain, or lymphopoietic system in either cohort. It is impossible to relate the observed mortality to levels of lead exposure; because of meager quantitative information prior to 1960. It is known that past exposures had been very high. Ethnicity, diet, alcohol, and cigarette smoking could not be ruled out as possible confounding etiologic factors for the cancer deaths.

The use of unconventional remedies among HIV-positive men living in California.

This study compared use of unconventional remedies in two groups of HIV-positive men (N = 63). Employing a multiple-choice questionnaire, the authors assessed the use of and attitudes toward unconventional remedies among two groups of white HIV-positive men similar in age, socioeconomic status, and severity of illness, all of whom lived in Northern California. One group (n = 36) participated in AIDS clinical trial protocols; the other group (n = 27) received health care at a community health center. Participants at all sites expressed positive views upon increasing unconventional remedies. Individuals enrolled in the clinical trial protocols for investigational drugs used unconventional remedies significantly less than the community health center participants, who were enrolled in an open clinical trial of hypericin, an unproven remedy.

A method for volume determination of the orbit and its contents by high resolution axial tomography and quantitative digital image analysis.

The various congenital and acquired conditions which alter orbital volume are reviewed. Previous investigative work to determine orbital capacity is summarized. Since these studies were confined to postmortem evaluations, the need for a technique to measure orbital volume in the living state is presented. A method for volume determination of the orbit and its contents by high-resolution axial tomography and quantitative digital image analysis is reported. This procedure has proven to be accurate (the discrepancy between direct and computed measurements ranged from 0.2% to 4%) and reproducible (greater than 98%). The application of this method to representative clinical problems is presented and discussed. The establishment of a diagnostic system versatile enough to expand the usefulness of computerized axial tomography and polytomography should add a new dimension to ophthalmic investigation and treatment.