Occupational risks for cutaneous melanoma among men in Sweden.

A population-based linked-registry was used to evaluate incidence of malignant melanoma of the skin among Swedish men by industry and occupation. There were 3850 cutaneous melanoma cases identified in the 19-year follow-up of men employed in 1960. New associations were observed for men employed in the breweries and malt-processing industry and in shoe fabrication from leather and skins. Several findings supported associations previously reported in other countries, including an excess risk among workers in basic chemical production and the printing industry and among professional, technical, and white-collar workers. Risk overall was not increased among farmers, despite a significant excess of melanoma of the face, neck, and scalp. Although this linked registry analysis lacked information about specific agents, duration of employment, and occupational and recreational sun exposures, it did provide leads for new associations and confirmed previous ones. Nevertheless, because of these limitations, etiologic clues must be interpreted cautiously.

Occupation and hematopoietic and lymphoproliferative malignancies among women: a linked registry study.

Using a nationwide linked registry, we evaluated the incidence of several hematopoietic and lymphoproliferative (HLP) malignancies among Swedish women from 1961 to 1979 by industry and occupation. The risks of one or more types of HLP cancers (including the leukemias, non-Hodgkin's lymphoma, multiple myeloma, and mycosis fungoides) were significantly increased among women working in the agriculture and textile industries, housekeepers, and post office employees. Limitations of these linked-registry data include lack of detailed information on specific exposures and duration of employment, and the relatively small sizes of specific occupational cohorts. Nevertheless, as the proportion of women entering the workforce continues to increase, this data resource may provide additional clues to occupational determinants of HLP and other malignancies.

Occupation and stomach cancer in a cohort of Swedish men.

Using the Cancer-Environment Registry of Sweden, which links the 1960 census information on employment with cancer incidence data from 1961-1979, we conducted a systematic, population-based assessment of stomach cancer incidence by industry and occupation for men in Sweden. Nearly 17,000 stomach cancer cases were diagnosed during the 19 years of follow-up. Stomach cancer incidence was elevated among miners and quarrymen, farmers and fishermen, and craftsmen and production workers. Men who held white collar jobs, including professional and technical, administrative and management, clerical, and sales jobs, had a reduction in stomach cancer incidence. Examination of specific jobs revealed generally elevated rates of stomach cancer among men who may be exposed to dusty work environments, such as quarry workers, stone cutters, circular and plane operators, construction workers, crane operators, heavy laborers, and shop and construction metal workers. These occupational associations mostly were observed for stomach cancers of noncardia origin, and no significant associations were found with cardia cancers. We had no information on dietary or other potential confounding factors and cannot make inferences about the role of occupation per se, but the current findings support those of earlier investigations and add to the evidence of a small but significant occupational role in stomach carcinogenesis.

Occupational risks for colon cancer in Sweden.

Using the Cancer-Environment Registry of Sweden, which links census information (1960) with cancer incidence data (1961 to 1979), we conducted a systematic, population-based assessment of colon cancer incidence among cohorts defined by industry and occupation for all employed persons in Sweden. Small but statistically significant excesses of colon cancer were observed among white-collar occupations, including administrators, professionals, and clerical and sales workers, whereas a reduction in incidence was found among workers in agricultural and related jobs, such as farmers, fishermen, and hunters. Analysis by subsite within the colon revealed little difference in results. The observed risk patterns are consistent with previous reports on colon cancer risk and occupational physical activity levels, ie, elevated risk among sedentary white-collar workers and reduced risk among agricultural workers. Few craftsman and production processing jobs were linked to colon cancer, although statistically significant excesses were observed among shoe and leather workers, metal smiths, and foundry workers in the metal manufacturing industry. The findings indicate that occupation in general is likely to play a relatively small role in colon cancer etiology, with perhaps its major contribution an indirect one via physical activity.

non-Hodgkin's lymphoma and occupation in Sweden: a registry based analysis.

Incidence of non-Hodgkin's lymphoma in different employment categories was evaluated from the Swedish Cancer-Environment Registry, which links cancer incidence during 1961 to 1979 with occupational information from the 1960 census. New associations were found for men employed in shoemaking and shoe repair, porcelain and earthenware industries, education, and other white collar occupations. Several findings supported associations found in other countries, including excesses among woodworkers, furniture makers, electric power plant workers, farmers, dairy workers, lorry drivers, and other land transport workers. Risks were not increased among chemists, chemical or rubber manufacturing workers, or petrochemical refinery workers. Caution must be used in drawing causal inferences from these linked registry data because information on exposure and duration of employment is not available. Nevertheless, this study has suggested new clues to possible occupational determinants of non-Hodgkin's lymphoma.

Ultrastructural studies of the ontogeny of fetal human and porcine endocrine pancreas, with special reference to colocalization of the four major islet hormones.

Most, if not all, endocrine cells seem capable of synthesizing and storing more than one hormone. Such cellular colocalization of hormones can be due either to the presence of two or more specific granules within the cells or to colocalization of the hormones within a single granule. The present study was performed to clarify the subcellular localization of insulin, glucagon, somatostatin, and pancreatic polypeptide within the endocrine cells of the human and porcine pancreas during fetal development, with special reference to possible colocalization of the hormones. The tissue specimens were processed for ultrastructural cytochemistry using Lowicryl as embedding medium. An immunogold labeling technique was used with two parallel, but not interacting, antibody chains. Sections from each specimen were double labeled in different combinations giving a complete covering of the four major islet hormones. During fetal life (50-90 days prenatally in porcine pancreas, 14 weeks gestation in the human pancreas) several hormones were demonstrated, not only in the same endocrine cells, but also in the same secretory granules (polyhormonal granules). Costorage of insulin, glucagon, somatostatin, and pancreatic polypeptide was demonstrated in granules in pancreatic endocrine fetal cells. At an early fetal stage, the endocrine cells contained either dense, round granules or pale, heteromorphous granules. With increasing age and maturation of the endocrine cells, structural differentiation of the secretory granules was found to be associated with a gradual disappearance of the polyhormonal granules. The first genuine monohormonal cell to appear in the porcine fetus was the pancreatic polypeptide cell (at 70 days gestation); it was followed by the somatostatin-producing endocrine cell. Mature insulin- and glucagon-producing cells were only demonstrated after birth. Thus, in the adult pancreatic endocrine cells, each specific endocrine cell type produced only one of the four classical hormones. The present investigation demonstrated that the endocrine cells of the fetal, but not the adult, pancreas are able to synthesize all the major islet hormones, and that these peptides are costored in the same granule. The data obtained support the concept of a common precursor stem cell for pancreatic hormone-producing cells.

Distribution of insulin binding sites on Leydig cells of rat testes using insulin-coated gold particles.

The distribution of insulin binding sites in Leydig cells dispersed with collagenase from rat testes was studied using insulin-coated gold particles as an electron opaque ligand. Using electron microscope is convenient to distinguish Leydig cells among a variety of cells in crude preparations by their ultrastructural characteristics. Leydig cells were shown to possess insulin-binding sites on their plasma membranes. Initial binding sites of insulin were located to the microvillous surfaces. Following binding, receptor-ligand complexes seemed to move to the intermicrovillous plasma membrane, then to be internalized. Two modes of the internalization were confirmed. Most of the receptor-ligand complexes on Leydig cells appeared to be internalized via large, uncoated plasma membrane invaginations, while the remainder became internalized via small pits into vesicles. The receptor-ligand complexes were subsequently transferred to large subsurface vacuoles with electron-lucent lumens believed to correspond to endosomes. The reason why IGCs on the postendosomal pathway moving toward lysosomes was also discussed.

Renal cell cancer among architects and allied professionals in Sweden.

The Swedish Cancer-Environment Registry was used to evaluate a recent report of a large excess risk of renal cell cancer among architects in Los Angeles. We identified 131 renal cell cancers among male Swedish architects and allied professionals during a 19-year follow-up period (1961-1979). Compared with the Swedish population, there was no significant excess of renal cell cancer among architects and allied professionals (standardized incidence ratio (SIR) = 1.15; 131 cases). Although it was not possible to estimate the risk for architects alone, the SIR was only 1.06 (16 cases) in a subset of professionals employed in architectural and engineering firms. However, a significant increase in risk (SIR = 1.38) was observed in a related group of workers employed as engineers and construction supervisors in the home construction industry.

Malignant melanoma in the printing industry.

To evaluate a recent report of malignant melanoma among printers, we used the Cancer-Environment Registry of Sweden, which links national cancer incidence and employment data. Employees in the newspaper printing industry had almost twice the incidence of melanoma than expected (p less than 0.01). Elevated risks were found not only among typographers and machine repairers, but also among journalists, editors, and business executives in the printing industry. Further studies are needed to clarify this relationship and identify specific exposures that may be responsible.

Uraemic and 1-alpha-hydroxycholecalciferol induced aortic lesions.

Aortic alterations in uraemic rats were studied ultrastructurally. The main changes consisted of degeneration and necrosis of smooth muscle cells and occurrence of extracellular calcifications. These alterations were aggravated when 1-alpha-hydroxycholecalciferol (1-alpha-OH-D3) was given in a slightly hypercalcaemic dose. Parathyroidectomy prevented, to some degree, the development of ultrastructurally demonstrable changes; this effect was abolished when 1-alpha-OH-D3 was given. The influence of 1-alpha-OH-D3 and parathyroidectomy on the aorta in uraemia was not solely a function of their effect on the serum calcium X phosphate product. Bodies composed of concentrically arranged (target-like) ring formations (1,200-6,000 A in diameter), possibly originating from degenerated smooth myocytes, were observed in the aortae of uraemic rats. These bodies may represent the matrix for initial calcification in the ground substance. The calcium salt deposits in the target-like bodies disappears when the tissues are stored in glutaraldehyde solutions for a long period of time. Calcifications were normally only found extracellularly, and it is proposed that the target-like bodies may locally initiate the calcification process.

Leukemias and occupation in Sweden: a registry-based analysis.

A linked-registry was used to examine systematically, on a national basis, the leukemia incidence in Swedish men by industry and occupation. New associations were observed for chronic lymphocytic leukemia among cloth and pattern cutters and for chronic myelocytic leukemia among brewery workers and motor mechanics. A number of additional findings were consistent with previous observations in other countries. Although etiologic inferences are limited when using linked-registry data, this hypothesis-generating study may provide new clues to the occupational determinants of specific forms of leukemia.

Occupational risks for bladder cancer among men in Sweden.

With the use of the Swedish Cancer-Environment Registry, census data on employment in 1960 were linked with registry data on bladder cancer during 1961-79. This hypothesis-generating study revealed for the first time associations between bladder cancer and employment in pulp and fiberboard manufacturing, in rope and twine making, and work as a dental technician. Statistically significant increases in risk were also found for several occupations previously associated with bladder cancer, including barbers and beauticians, artistic painters, toolmakers and machinists, and physicians, and employment in butcher shops, industrial chemical making, apparel manufacturing, and plumbing. Etiologic inferences cannot be made from this investigation, but the findings from this large national resource provide further clues to the occupational determinants of bladder cancer.

Peritoneal mesothelioma in the construction industry in Sweden.

As a follow-up to a recent examination of occupation and pleural mesothelioma in Sweden, we evaluated peritoneal mesothelioma using the Swedish Cancer-Environment Registry. There were 35 microscopically confirmed cases of peritoneal mesothelioma among employed men during the period 1961 to 1979. Almost 40% of cases were in the construction industry, with insulation workers at especially high risk (standardized incidence ratio = 163.9, 4 cases, P less than .001). Other groups such as textile and paper and pulp workers and painters showed nonsignificant increases in risk. These findings are consistent with previous studies in their countries, and demonstrate the usefulness of registry epidemiology in assessing occupational relationships to cancer.

Macrophage stimulation with some structurally related polysaccharides.

The macrophage-stimulating properties of some structurally related polysaccharides were studied in vitro. When the polysaccharides were presented to the macrophages in a sterically fixed form, i.e. as microparticles, they induced the release of interleukin 1 (IL-1) from the macrophages. Microparticulate 1.3-beta-glucan (curdlan) induced nonspecific macrophage mediated tumour cell killing while 1.4-alpha-glucan (starch), 1.6-alpha-glucan (dextran), and 1.6-alpha-mannan were without effect. The corresponding soluble polysaccharides did not stimulate the macrophages. Kinetic studies showed that although IL-1 was released immediately after stimulation, the macrophages needed a time lag of several days to develop tumour cytotoxicity. The development of cytotoxicity paralleled binding of tumour cells to the macrophages. Resident and inflammatory peritoneal macrophages showed differences in their responses to the polysaccharides. Stationary, resident peritoneal macrophages stimulated by macroparticles secreted high levels of IL-1 but expressed a low cytotoxic activity, while newly recruited inflammatory macrophages released lower levels of IL-1 but readily killed the tumour cells. The influence of cyclo-oxygenase products on the IL-1 release and macrophage cytotoxicity was also investigated. When cyclo-oxygenase was blocked with indomethacin, a significantly higher release of IL-1, and then an increased cytotoxicity, were obtained with 1.3-beta-glucan stimulated macrophages. The results suggest that microparticulate polysaccharides may be useful for studies on the induction of macrophage differentiation and also for studies on nonspecific cellular immune responses in vitro and in vivo.

Occupational risks for renal cancer in Sweden.

A systematic assessment was made of the occurrence of renal cancer among men by industrial and occupational classification using the Cancer-Environment Registry, which links cancer incidence (1961-79) and census data (1960) with industry and occupation for all employed individuals in Sweden. Data were analysed separately for cancers of the renal parenchyma and pelvis. Significantly increased risks for renal cell cancer were observed for several professional and white collar occupations, including physicians and others in the health care industry. By contrast, the risks for renal pelvis cancer tended to be higher among blue collar workers, especially in the machine industry. Deficits of both cancers occurred among farmers. The findings of the survey are considered as aetiological clues that may deserve further study, although some associations support observations in other countries.