Morbidity and mortality in talc-exposed workers

Cancer incidence and cause-specific mortality were studied in a male cohort of 94 talc miners and 295 talc millers, exposed to non-asbestiform talc with low quartz content. No excess risk was found compared with national age-specific incidence. Six cases of lung cancer occurred versus 6.49 expected (miners: observed 2, expected 1.27; millers: observed 4, expected 5.22). There were 3 deaths due to non-malignant respiratory disease against 10.9 expected (miners: observed 1, expected 2.5; millers: observed 2, expected 8.4). Mesothelioma, tuberculosis, or pneumoconiosis were not recorded as causes of death. Pneumoconiosis was noted as a contributory cause in three cases (silicosis two, talcosis one). Further follow-up will reduce any potential impact of "healthy worker" selection.

Incidence of cancer among ferrochromium and ferrosilicon workers: an extended observation period

Results are presented of a cohort study on the incidence of cancers and crude death rates in ferrochromium and ferrosilicon workers. The whole cohort was observed from 1 January 1953 to 31 December 1985. Two sets of results are presented; one restricted to workers first employed before 1960 and one to workers first employed before 1965. The latter cohort consists of 1235 workers. The total mortality in the whole cohort was low (SMR = 81) as was the overall incidence of cancers (SIR = 84). There was an overall deficit of deaths and cases of cancer in the ferrosilicon group. An excess of lung cancer (SIR = 154) and cancer of the prostate (SIR = 151) was observed in the ferrochromium workers employed before 1965. Cancer of the kidney was also in excess (SIR = 273) in the ferrochromium group, with a mean "latency time" of 39 years. Two cases of malignant melanomas had occurred versus 0.19 expected in a small subgroup of workers in electrical shops and an electric power station.

Incidence of cancer among welders and other workers in a Norwegian shipyard

The incidence of cancer among 4778 male shipyard workers, including 783 mild steel welders, was investigated in a historical cohort study. The workers had been employed for at least three months between 1 January 1946 and 31 March 1977. The incidence of cancer was observed from 1 January 1953 through 1986. The loss during follow-up was only 0.9%. There were 53 observed cases of lung cancer in the whole cohort versus 31.3 expected on the basis of the national rates for men. There was an increased incidence of lung cancer among the welders, with seven observed cases versus 3.2 expected. Twenty-two cases of bladder cancer were observed versus 15.2 expected. Two malignant mesotheliomas had occurred (0.7 expected). Smoking was likely to be a confounder in the present study. Due to concomitant exposure to asbestos, the results are inconclusive concerning the possible relationship between exposure to welding fumes and lung cancer.

Two dimensional gel human protein databases offer a systematic approach to the study of cell proliferation and differentiation

Human cellular protein databases have been established using computer-analyzed 2D gel electrophoresis. These databases, which include information on various properties of proteins, offer a global approach to the study of regulation of cell proliferation and differentiation. Furthermore, thanks to the advent of microsequencing the databases make it possible to directly link protein and DNA information.

Incidence of cancer in a cohort of magnesium production workers

The results from a cohort study on the incidence of cancer and the mortality in a cohort of 2391 male workers producing magnesium metal are presented. The study population was restricted to employees with more than one year of work experience in the study plant between 1951 and 1974 and the cohort was observed from 1953 to 1984. Altogether 152 new cases of cancer were observed versus 132.6 expected. Six cases of cancer of the lip were found against 2.3 expected, 21 of stomach cancer against 12.8 expected, and 32 of lung cancer against 18.2 expected. A possible causal relation between exposure to factors in the work environment and the development of cancer is discussed.

House dust mite, Dermatophagoides pteronyssinus, and its allergens: effects of washing

The study was undertaken to evaluate the effect washing at various temperatures would have on the house dust mite, Dermatophagoides pteronyssinus, and its allergens. Young and old mite cultures underwent a simulated washing programme. To record the number of live mites prior to and after washing a new counting method was applied. The findings demonstrated that although washing reduced the number of live mites, a washing programme at minimum temperature 58 degrees C was required in order to achieve complete extermination of the house dust mites. A distinct protein loss was observed when washing at higher temperature, thus further reducing the total allergen pool without loss of allergen activity as determined by direct RAST.

The suitability of a new index for the evaluation of dental wear

The suitability of a new index for rating dental wear by different observers was tested. Four dentists, who were first calibrated using the scoring system and then subjected to an inter-examiner agreement test before and after a field study, rated 167 individuals in total in their private dental practices. The incisal/occlusal state of the teeth with regard to restorations and dental wear was recorded. The inter-examiner agreement test proved satisfactory when rating main groups of wear but not so good when rating subcategories. However, a marked improvement in agreement developed between the first and the second test. The individuals composing the field study group are probably not representative of Scandinavian populations in general. Relatively few teeth were missing, and the teeth were well restored. Only the highest age group (80-89 years) displayed the most severe degree of wear to any extent. However, wear into the dentin was observed in 20% of the teeth already in the youngest age group (20-29 years). These teeth were solely incisors and canines of both jaws. In conclusion, we found that the index should be well suited for the evaluation of dental wear in large groups of people by different investigators after adequate training in use of the system has been provided and that tooth wear may be a relatively small problem in urban Scandinavian populations with regular dental care.

Cancer in waiters

The risk of cancer was studied in 2,413 males registered as waiters at the 1960 census in Norway. A personal identification number was used in linking this cohort of waiters with the Norwegian Cancer Registry. The follow-up period was 1961-1984. An excess risk of cancer was observed for the following primary sites: upper respiratory and digestive tracts combined 42 observed against 11.3 expected, liver (14 versus 2.87), rectum (28 versus 13.89), and lung (67 versus 43.66). The highest risk for all these types of cancer was seen among those who were waiters at both censuses in 1960 and 1970. In the case of cancer of the stomach the observed number of cases was significantly lower than expected (14 versus 25.68). It is known that smoking habits and alcohol consumption are substantial aetiological factors for the types of cancer in which an excess risk has been demonstrated here.

Hemodilution increases cerebral blood flow in acute ischemic stroke

We measured cerebral blood flow in 10 consecutive, but selected, patients with acute ischemic stroke (less than 48 hours after onset) before and after hemodilution. Cerebral blood flow was measured by xenon-133 inhalation and emission tomography, and only patients with focal hypoperfusion in clinically relevant areas were included. Hemodilution was done according to the hematocrit level: for a hematocrit greater than or equal to 42%, 500 ml whole blood was drawn and replaced by the same volume of dextran 40; for a hematocrit between 37% and 42%, only 250 ml whole blood was drawn and replaced by 500 cc of dextran 40. Mean hematocrit was reduced by 16%, from 46 +/- 5% (SD) to 39 +/- 5% (SD) (p less than 0.001). Cerebral blood flow increased in both hemispheres by an average of 20.9% (p less than 0.001). Regional cerebral blood flow increased in the ischemic areas in all cases, on an average of 21.4 +/- 12.0% (SD) (p less than 0.001). In three patients, a significant redistribution of flow in favor of the hypoperfused areas was observed, and in six patients, the fractional cerebral blood flow increase in the hypoperfused areas was of the same magnitude as in the remainder of the brain. In the last patient, cerebral blood flow increased relatively less in the ischemic areas. Our findings show that cerebral blood flow increases in the ischemic areas after hemodilution therapy in stroke patients. The marked regional cerebral blood flow increase seen in some patients could imply an improved oxygen delivery to the ischemic tissue.

CBF decreases after calcium antagonist treatment in acute ischemic stroke

The effect of the possible influence of a new calcium antagonist, PY 108-068, on regional cerebral blood flow (CBF) was studied in patients suffering acute ischemic stroke. The dosage was 1.5 + 2.5 mg intravenously in six patients (series 1) and 2.5 + 5.0 mg intravenously in five other patients (series 2). CBF was measured before and after treatment by xenon-133 inhalation and single photon emission computed tomography (Tomomatic 64). In the first series, no changes in hemispheric CBF, arterial blood pressure, or clinical symptoms were noted after treatment, but one patient showed an increase of CBF in part of the peri-infarct area. In the second series, slight increases in mean hemispheric flow values were seen, but in three of the five patients CBF decreased even further in the ischemic area. Arterial blood pressure decreased by 13%, and the clinical symptoms were unchanged. In conclusion the results shows, that calcium antagonist may be harmful in acute ischemic strokes since it can decrease the cerebral blood flow further in the ischemic areas. A potential beneficial metabolic effect of an calcium antagonist in ischemic tissue may thus be overshadowed by a harmful flow decrease.

Isolation and characterization of an allergen-rich fraction derived from cultures of Dermatophagoides pteronyssinus. Preliminary purification of a protein

An allergen-rich fraction derived from mature cultures of Dermatophagoides pteronyssinus was isolated. Results of radio-allergosorbent tests and the disclosure of IgE-binding proteins after their electrophoretic transfer from sodium dodecyl sulphate-polyacrylamide gel to nitrocellulose sheets revealed that both important groups of allergens, Der p I and Der p II, seem to be contained in the above-mentioned fraction. Analysis using crossed immuno-electrophoresis (CIE) disclosed 5-7 antigens and a corresponding enzymatic assay for the specificity of patient's IgE in CIE revealed that 4 of the antigens also are allergens. Moreover, an allergen was detected which apparently was not discovered when using CIE. The fraction in question was fractionated further and subsequent analysis by CIE indicated the purification of 1 antigen.

Histopathology of sinonasal and lung cancers in nickel refinery workers

Histopathological diagnoses were compiled for 100 sinonasal cancers and 259 lung cancers in nickel refinery workers, including cases from Wales, Canada, and Norway. The sinonasal cancers comprised squamous cell carcinomas (48 percent), anaplastic and undifferentiated carcinomas (39 percent), adenocarcinomas (6 percent), transitional cell carcinomas (3 percent), and other malignant tumors (4 percent). The lung tumors comprised squamous cell carcinomas (67 percent), anaplastic, small cell, and oat cell carcinomas (15 percent), adenocarcinomas (8 percent), large cell carcinomas (3 percent), other malignant tumors (1 percent), and cancers not otherwise specified (6 percent). Possible selection bias in these data cannot be excluded, since the histological diagnoses represent 63 percent, 68 percent, and 100 percent of cases of sinonasal cancer and 24 percent, 47 percent, and 86 percent of cases of lung cancer in the Welsh, Canadian, and Norwegian workers. This study suggests that (a) the sinonasal cancers in nickel refinery workers conformed to the usual distribution of histological types observed in the general population (in contrast to the predilection for adenocarcinomas in wood workers), and (b) the lung cancers in nickel-refinery workers showed preponderance of squamous cell carcinomas and deficit of adenocarcinomas, compared to prevalent proportions of these neoplasms, possibly reflecting the paucity of women in the cohorts and temporal trends during the six decades in which the tumors were diagnosed.

Domain VI of Escherichia coli 23 S ribosomal RNA. Structure, assembly and function

Domain VI at the 3' end of the 23 S ribosomal RNA from Escherichia coli was prepared using the in vitro T7 RNA polymerase system. Its structure was examined by probing with ribonucleases and chemical reagents, including a psoralen derivative, of various nucleotide specificities, using a reverse transcriptase procedure for analysis. The data provided support for the most recent secondary structure derived from phylogenetic sequence comparisons and for additional structuring that was inferred from earlier experimental data. Moreover, the structure was essentially the same in the free domain, in renatured 23 S RNA and in 50 S subunits. Protein L3 bound to the isolated domain and its binding site was located at a long-range double helix containing a large internal loop. This structure is unusual for a protein-RNA binding site and it may characterize a new (third) class of site. Protein L3 has been implicated, together with L24, in initiating assembly of the 50 S subunit and it shares the exceptional property with L24 that it binds adjacent to the junction of two RNA domains from where it can maximally influence RNA folding. Protein L6 also assembled to domain VI and, in a control experiment, protein L2 bound to isolated domain IV. Domain VI was largely inaccessible in the 50 S subunit and the few accessible RNA sites occurred mainly within conserved sequence regions that constitute potential functional sites. alpha-Sarcin inactivates ribosomes by cutting at one of these sites in 50 S subunits; it also recognized the same site in the free 23 S RNA and in the free domain. Both the EF-Tu ternary complex, and the EF-G ternary complex stabilized by fusidic acid or by a non-hydrolyzable GTP derivative, inhibited alpha-sarcin attack while non-enzymatically bound tRNA did not, thus providing evidence, more direct than before, for the involvement of the RNA region in a common elongation factor binding site.

Elevated serum CA 125 levels prior to diagnosis of ovarian neoplasia: relevance for early detection of ovarian cancer

To investigate the sensitivity of the CA 125 immunoradiometric assay for occult ovarian neoplasia, serum CA 125 levels were retrospectively determined "blind" in specimens collected from 105 women who subsequently developed ovarian neoplasia, and from 323 matched controls. The distribution of CA 125 levels was very different between the case and control populations (p = 0.0001) over the entire collection-to-diagnosis interval (range 1-143 months). Median CA 125 levels for all cases, and for those collected more than 24, 36 or even 60 months prior to diagnosis, were always 18 U/ml or greater, compared with a median of 10.9 U/ml for controls. Half of the cases collected within the 18 months preceding diagnosis had CA 125 levels of more than 30 U/ml and one-third had levels greater than 65 U/ml. About one-fourth of those collected prior to 60 months before diagnosis had levels above 30 U/ml. In contrast, approximately 7% and 0.9% of controls had levels in excess of 30 or 65 U/ml, respectively. Elevations occurred in cases eventually diagnosed with localized or advanced cancer, and with borderline or obviously malignant disease. These results provide an insight into the preclinical biology of ovarian neoplasia that may help in designing methods for early detection of this disease, and demonstrate the usefulness of the JANUS serum bank as a resource in evaluating serum tests.

Mortality and incidence of cancer among oil exposed workers in a Norwegian cable manufacturing company. Part 2. Mortality and cancer incidence 1953-84

Mortality and incidence of cancer 1953-84 was studied in a cohort of 529 men exposed to mineral oils in a Norwegian cable manufacturing company. Expected numbers of deaths were calculated from national death rates and cases of cancer from regional incidence rates. Among the 195 men who had worked for less than one year, there were statistically significant excesses of deaths from all causes (O/E = 75/39.3) and from malignant neoplasms, ischaemic heart disease, non-malignant respiratory disease, and violence. In a subcohort of all 248 men with known work category and at least one year's employment in oil exposed work statistically significant excesses of deaths from ischaemic heart disease (O/E = 26/16.1) and cases of lung cancer (O/E = 10/3.9) were observed. Nine of the cases of lung cancer had occurred 20 years or more after first employment (2.7 expected; p less than 0.01). In smokers of this subcohort there were 7.06 cases of lung cancer per 1000 person-years compared with 1.30 in smokers of a general population sample. It is concluded that exposure to mineral oils has probably been an important contributing factor in the development of lung cancer among these workers.

Serum thyroglobulin as a preclinical tumour marker in subgroups of thyroid cancer

Serum samples from a biological serum bank taken several years before the diagnosis of cancer, were analysed for S-Tg and S-TSH in 43 patients with thyroid cancer and compared to 128 healthy controls matched for age, sex, geographical region and time of blood sampling. The main finding was the difference in S-Tg between cases and controls, the highest values being found in sera from cases. Relative risk of thyroid cancer increases with increasing S-Tg levels (the global test giving P less than 0.0005). Extremely high levels were found in 4 cases with follicular and 3 with anaplastic cancers. No such statistically significant difference was found in S-TSH concentration. Possible explanations for the elevated S-Tg observed several years before clinically evident malignant tumour are discussed.

Mass screening for cervical cancer in Ostfold county of Norway 1959-77

In 1959, the Norwegian Cancer Society started a research project in Ostfold county to assess the effect of a mass screening program for cervical cancer. The program comprised 5 screening rounds during the period 1959-77. At each screening a clinical gynecological examination was performed in addition to the cytological test. A total of 45,960 women aged 25-59 years at the first screening were invited to participate. The follow-up, which was based on the data base of the Cancer Registry of Norway, lasted until December 31, 1982. For the follow-up period as a whole, the observed incidence and mortality were reduced to 78% and 83% of the expected values, respectively. Through the initial phase of the program there was a cumulation of patients with early-stage disease, while the incidence of advanced disease and mortality were reduced. In the later part of the follow-up period, a decrease in incidence of early and advanced disease as well as in mortality was observed. Women not participating in the screening program had a significantly higher risk of cervical carcinoma than the reference population, and a less favorable stage distribution as well. Among participants in the screening program, the reduction of risk was dependent upon the number of previous negative smears. Women with 5 previous negative smears had a risk of disease which was only 18% of that expected. Problems concerning choice of reference population, migration, attendance rates, sensitivity and specificity of the cytological tests and intervals between screenings are discussed. Also, the probable conversion rates of pre-cancerous lesions to cancer and the health hazards involved in possible over-treatment of pre-cancerous cases which otherwise would have regressed, are considered. A dynamic model is suggested. In order to achieve a reduction of mortality in the short term, the efforts of the program should initially be concentrated on older women. To achieve a reduction of incidence in the long run, younger women should gradually be included. Finally, special efforts should be made to increase attendance rates among high-risk women.

Localization of atrial natriuretic factor (ANF)-immunoreactive material in the hypothalamo-pituitary complex of the frog

The presence of atrial natriuretic factor (ANF)-like material in the hypothalamo-pituitary complex of the frog (Rana ridibunda) was studied by means of indirect immunofluorescence and immunogold techniques. In the hypothalamus, numerous ANF-positive cell bodies were located in the preoptic nucleus, the lateral forebrain bundle and the dorsal infundibular nucleus. The ventral infundibular area and the median eminence contained only ANF-immunoreactive fibers. A dense network of fibers and nerve terminals was observed in the neural lobe of the pituitary. Scarce nerve endings were also noted in the intermediate lobe whereas ANF-like immunoreactivity was totally absent in the anterior lobe of the pituitary. At the ultrastructural level, positive material appeared restricted to dense core vesicles (about 100 nm in diameter). These results demonstrate that an ANF-like substance is contained in nerve terminals of the frog pars nervosa, and support the hypothesis that ANF may exert a physiological role in the control of release of neurohypophyseal peptides.

Prognostic factors in renal cell carcinoma

We studied 569 cases of renal cell carcinoma in the files of the Department of Pathology of the Norwegian Radium Hospital from 1964 to 1974. A nephrectomy had been performed in all cases. Clinical information on sex, age, survival time and metastases was traced. The histological slides were examined and tumour growth pattern, cell type, cell shape, nuclear atypia, abnormal nucleoli, nuclear grade, vascular invasion and tumour demarcation were all evaluated. Besides well-known prognostic factors such as tumour stage, presence or absence of metastases and vascular invasion, nuclear grade was found to be a useful prognostic factor. Younger patients were found to do better than older, and women better than men. Smaller tumours carried a better prognosis than larger and clear cell tumours had a better prognosis than those composed of eosinophilic or basophilic cells. The presence of spindle cells was a bad prognostic omen.