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Biomedical subjects

P Gustavsson

Publications and source records attributed to P Gustavsson.

At least 73 records · Page 4Linked to original sources

Cancer incidence, mortality and exposure-response among Swedish man-made vitreous fiber production workers.

OBJECTIVE: The objective of this study was to provide an extended follow-up of workers in three Swedish plants producing man-made vitreous fibers (MMVF). METHOD: Mortality and cancer incidence was investigated among 3539 male and female workers, employed for at least one year before 1978. Mortality was followed from 1952 to 1990 and cancer incidence from 1958 to 1989. National and regional mortality and cancer incidence rates were used to calculate the expected numbers. RESULTS: Twenty-seven lung cancer deaths were observed compared with 23 expected (standardized mortality ratio 117, 95% confidence interval 81-176), based on regional mortality. With a latency time of 30 years, the lung cancer risk was significantly elevated, but not trend was found for the standardized mortality ratio with increasing duration of exposure to MMVF. The lung cancer and stomach cancer mortality was higher in the rock wool industry than in the fiber glass industry. Fiber exposure from 1938 to 1990 was estimated in the two rock wool plants by applying a model for historical fiber exposure estimation, specific for different job titles in the rock wool production industry. No relationship was found between individually cumulated rock wool fiber exposure and lung cancer or stomach cancer risk. CONCLUSIONS: The numbers of lung cancers and stomach cancer cases were low and did not therefore allow more general conclusions regarding the cancer hazard for exposed workers. A large European study in progress will probably allow more precise conclusions.

Adult↗

Mortality and cancer incidence in Stockholm fire fighters.

Fire fighters are exposed to irritating, asphyxiating, and toxic gases and aerosols, to psychological stress, and to physically demanding work. Due to differences in fire fighting techniques, exposure conditions for fire fighters differ among different countries. The purpose of this investigation was to study cancer incidence and mortality in fire fighters who have been working with fire fighting methods used in Sweden from the beginning of this century onwards. All male fire fighters employed for at least 1 year in the City of Stockholm during 1931-1983 were traced, and an index of the number of fires fought was calculated for each individual. The mortality during 1951-1986 (among 1, 116 fire fighters) was lower than expected (SMR = 82; 95% confidence interval 72-91) compared with local mortality rates, with a low mortality in circulatory diseases, obstructive lung diseases, violent deaths, and suicides. The cancer incidence in 1958-1986 was equal to the expected (SMR = 100; 95% confidence interval 83-119). However, an excess of stomach cancer (18 observed vs. 9.37 expected; SMR = 192, 95% CI 114-304) was observed. There was also a tendency for higher incidence and mortality in stomach and brain cancer with increasing number of fires. There were four deaths from brain cancer compared to 0.8 expected (SMR = 496; 95% CI 135-1270) in the highest exposure category. Fire fighters are, however, not systematically exposed to known stomach or brain carcinogens, and the results need confirmation in further studies with extensive exposure evaluations.

Aged↗

Contamination of beef carcasses by psychrotrophic Pseudomonas and Enterobacteriaceae at different stages along the processing line.

The extent of the contamination of beef carcasses with psychrotrophic Pseudomonas spp. and Enterobacteriaceae during slaughter, chilling and cutting was estimated by introducing a new analytical procedure; the contamination index. Comparisons were made between the initial viable counts and the contamination index. The contamination index was calculated as the sum of the bacterial counts obtained during aerobic cold storage of excised meat samples. The presence and composition of spoilage bacteria in the slaughter environment and on the carcasses was also determined at one plant. Rapid chilling was identified as a critical processing step by the contamination index. In addition to this, the dehiding and the chilling in cold storage rooms were implicated as critical operations, with respect to aerosol contamination and surface cross-contamination. Comparison of the composition of spoilage bacteria in the slaughter environment and the bacteria proliferating on the carcass surface samples taken at the corresponding steps showed similar distributions of the identified Pseudomonas spp. In five surveys at two plants, the contamination of beef carcasses along the processing line was estimated. Statistically significant variations between different processing steps were more pronounced for the contamination index than for the conventional counts. It was concluded that the contamination index could be used for identifying critical processing steps, with respect to the extent of contamination of carcasses by psychrotrophic spoilage bacteria.

Acinetobacter↗

Mortality and incidence of cancer in a cohort of Swedish chimney sweeps: an extended follow up study.

Despite 200 years of efforts to regulate safety in this occupation, chimney sweeps have increased mortality from cancer, ischaemic heart disease, and respiratory disease. Mortality and incidence of cancer were examined in a cohort of 5542 Swedish chimney sweeps employed through their national trade union at any time between 1918 and 1980. Previous studies of this cohort found increased risks of ischaemic heart disease, respiratory disease, accidental deaths, and various neoplasms. By increasing follow up, we sought to increase the power of the study and examine disease time trends. Mortality analysis was extended 7.5 years to cover the period 1951-90; cancer incidence analysis was extended six years to cover the period 1958-87. New findings include increased incidence and mortality of prostate cancer (SMR 169, 95% CI 106-256, 22 observed) and increased incidence of total haematolymphatic cancers (SIR 151, 95% CI 106-209, 36 observed). When only the most recent follow up period was analysed, previously observed risks persisted for total lung cancer (SIR 178, 95% CI 99-293), oat cell lung cancer (SIR 240, 95% CI 103-472), bladder cancer (SIR 247, 95% CI 131-422), and oesophageal cancer (Obs/Exp = 2/1.1). Mortality from ischaemic heart disease (SMR 98, 95% CI 76-123) and respiratory disease (SMR 111, 95% CI 56-199) declined during recent follow up, although significant excess mortality remained during analysis of the entire study period (ischaemic heart disease SMR 128, 95% CI 112-145; respiratory disease SMR 159, 95% CI 115-213). In analyses of the entire study period, risks of ischaemic heart disease and lung, bladder, and oesophageal cancer were adjusted for smoking; oesophageal cancer was also adjusted for use of alcohol. All risks remained significantly raised. Exposure-response analyses showed significant positive associations between duration of employment and risks for mortality from lung, oesophageal, and total cancer. Chimney sweeps remain at increased risk for cancers of the lung, oesophagus, and bladder. Our study supports a casual role for exposure to chimney soot, which contains carcinogens including polycyclic aromatic hydrocarbons. Extended follow up of this cohort now shows increased risks of prostate and haematolymphatic cancers.

Adolescent↗

Lung cancer risk among workers exposed to man-made mineral fibers (MMMF) in the Swedish prefabricated house industry.

Mortality and cancer incidence was investigated among 2,807 workers, employed for at least one year before 1972, at 11 Swedish companies manufacturing prefabricated wooden houses. A total of 1,068 workers had been exposed to man-made mineral fibers (MMMF) used for insulation. Mortality was followed from 1969 to 1988 and cancer incidence from 1969 to 1985. Exposure conditions were investigated at all plants. There were 14 deaths from lung cancer in the total cohort, whereas 20.7 would be expected (SMR = 68; 95% CI:37-113), based on regional mortality. After a latency of 20 years of more, two lung cancer cases had occurred among all workers exposed to MMMF, whereas 4.3 would be expected (SMR = 46; 95% CI: 5-168). The exposure levels that have prevailed do not seem to be associated with an increased lung cancer rate, but extended follow-up is necessary for a definitive evaluation.

Cohort Studies↗

Memory effects of clomipramine treatment: relationship to CSF monoamine metabolites and drug concentrations in plasma.

Performance on tasks tapping automatic and voluntary aspects of memory, attention, and motor speed was examined in 14 patients with major depressive disorder, before and after 3 weeks of treatment with clomipramine (150 mg/day), a potent serotonin and noradrenaline uptake blocker with anticholinergic side effects. Performance on tasks requiring frontal functions improved or did not change, whereas verbal learning and retention, where hippocampal functioning is critical, were impaired. The latter tasks were negatively related to cerebrospinal fluid (CSF) 5-HIAA levels and plasma concentration of clomipramine. The results provide further support for the regulatory role of monoaminergic systems in cognition. Furthermore, we found the automatic-voluntary capacity distinction less heuristically useful. Physiological mechanisms regulating different aspects of cognition and memory appeared to be more closely related to the type of task used than to its capacity-demanding properties.

Adult↗

Neuropsychiatric symptoms among welders exposed to neurotoxic metals.

Neuropsychiatric symptoms in 65 welders exposed to aluminium and 217 railroad track welders were studied with the aid of a previously validated questionnaire. Semiquantitative data on exposure to the metals aluminium, chromium, lead, manganese, and nickel were also recorded by questionnaire. Logistic regression was employed to study the relation between exposure and the prevalence of symptoms. Welders exposed to aluminium, lead, or manganese for a long period had significantly more neuropsychiatric symptoms than welders not exposed to these metals. The results indicate that detailed psychometric studies should be performed on welders exposed long term to specific metals as such exposures might affect their nervous system.

Adult↗

Mortality and incidence of cancer among Swedish gas workers.

The mortality and incidence of cancer was studied among 295 workers at a Swedish gas production company. All men employed for at least one year between 1965 and 1972 were included in the study. The follow up period for mortality was 1966 to 1986, and the incidence of cancer was followed up from 1966 to 1983. Expected numbers of deaths were based on local death rates among occupationally active men, the expected numbers of cancer were based on national statistics. The total mortality was increased, mainly due to an excess of deaths from circulatory diseases. The excess was larger after long follow up and after long employment periods. Two cases of cancer in the nose and nasal sinuses were found; there was no excess of lung cancer. Smoking habits were investigated for a subset of the cohort and did not differ from the average for men in large cities. The findings are discussed in relation to other studies of soot and combustion exposed workers.

Adult↗

Lung cancer and exposure to diesel exhaust among bus garage workers.

Mortality and cancer incidence was investigated among the 695 bus garage workers employed as mechanics, servicemen, or hostlers for at least six months in five bus garages in Stockholm between 1945 and 1970. The exposure to diesel exhaust and asbestos was estimated by industrial hygienists. A small excess of lung cancer mortality was found in the cohort when occupationally active men in Stockholm were used as the reference group. A case-referent study was performed within the cohort, six referents being selected for each of the 20 lung cancer cases. The lung cancer risk increased with increasing cumulative exposure to diesel exhaust, but not with cumulative asbestos exposure. The relative risk for lung cancer among the highly exposed men was 2.4 (95% CI 1.3-4.5) as compared with those with low exposure. The study indicates that exposure to diesel exhaust increases the risk for lung cancer.

Asbestos↗

Mortality among workers at a municipal waste incinerator.

Mortality was investigated among 176 male workers employed for at least 1 year between 1920 and 1985 at a municipal waste incinerator. Expected numbers of deaths from 1951 to 1985 were calculated from national and local death rates, standardized for age and calendar year. There was an excess of deaths from lung cancer and, after long follow-up, for ischemic heart disease. Analysis of duration of exposure supported that the excess of ischemic heart disease was caused by occupational factors; the lung cancer cases were too few to permit conclusions in this respect. Exposure to combustion products and polycyclic aromatic compounds were common, but other occupational exposures may also have contributed to the risk excesses. Smoking habits were investigated and did not differ from the average for Swedish men in cities and towns. Some work operations are very dusty and should be performed only with appropriate protection devices.

Adolescent↗

Excess of cancer in Swedish chimney sweeps.

The incidence of cancer was investigated among 5266 Swedish chimney sweeps employed for any period between 1918 and 1980. An analysis of the mortality has been reported earlier and showed an increased number of deaths from coronary heart disease, respiratory diseases, and lung, oesophageal, and liver cancer. Excess risks for cancer of the lung and oesophagus were confirmed in this analysis. Among the lung cancers, both squamous cell carcinoma and oatcell/undifferentiated carcinoma were in excess. In addition, a more than doubled risk for bladder cancer (23 observed v 9.8 expected cases) and an increase of malignancies of the haematopoietic system was found. There were, however, no cases of scrotal cancer, the classic occupational hazard among chimney sweeps. Chimney sweeps are exposed to polycyclic aromatic hydrocarbons generated by the combustion of organic material (coal, wood, coke, and oil). They are also exposed to cancerogenic metals (arsenic, nickel, and chromium). These results support the need for improved working conditions.

Carcinoma, Small Cell↗

Climbing fibres projecting to cat cerebellar anterior lobe activated by cutaneous A and C fibres.

1. Climbing fibre responses evoked on stimulation of the ipsilateral superficial radial nerve were examined in the forelimb area of the C3 zone in the barbiturate-anaesthetized cat. Climbing fibre responses were recorded in sixty-five Purkinje cells and as field potentials from the surface of the cerebellum. 2. In addition to the previously described A beta-fibre-evoked climbing fibre response, late climbing fibre responses were consistently evoked in all Purkinje cells studied when C fibres were stimulated. The latencies of the A beta- and C-fibre-evoked climbing fibre responses were 11-20 ms and 110-220 ms, respectively. In most experiments climbing fibre responses with an intermediate latency (20-30 ms) were evoked. It was demonstrated that this response depended on A delta fibres. 3. The long-latency climbing fibre response generated by electrical stimulation at C-fibre strength was evoked also during selective anodal block of conduction in A fibres (Brown & Hamman, 1972). Hence, impulses in C fibres were sufficient for generation of climbing fibre responses. 4. The distribution within the forelimb area of the C3 zone of the A beta- and C-fibre-evoked climbing fibre field potential was similar. No climbing fibre response was evoked in this area of the C3 zone by stimulation of A and C fibres in the contralateral superficial radial nerve or in the plantar nerves of the hind limbs. 5. It can be concluded that climbing fibres projecting to the forelimb area of the C3 zone in the cerebellum receive a somatotopically organized input from both A beta and C fibres.

Action Potentials↗

Excess mortality among Swedish chimney sweeps.

In a cohort study of 5464 union organised Swedish chimney sweeps employed at any time between 1918 and 1980 mortality was studied from 1951 to 1982 with national statistics used as a reference. Follow up was possible for 98.6% of the individuals: 717 deaths were observed against 540 expected. There was an increased mortality from coronary heart disease, respiratory diseases, and several types of malignant tumours. Lung cancer mortality was significantly increased and positively correlated to the number of years employed. A fivefold risk increase for oesophageal cancer and liver cancer was found. The increased mortality could be attributed to exposure to combustion products in the work environment but not to smoking habits.

Adult↗

Possible causes of increased lung cancer incidence among butchers and slaughterhouse workers.

An excess of lung cancer among butchers and slaughterhouse workers has been reported in several record-linkage studies. In this case-referent investigation on the possibility of occupational exposures being related to the lung cancer excess, cases and referents were selected from butchers and slaughterhouse workers registered in the Swedish national census of 1960. The case group comprised all men in the study population dying from lung cancer between 1971 and 1982. Two reference groups were formed, ie, all individuals dying from other cancers and a random sample of all dead men in the study population during the same time period. The history of occupations, occupational exposures, and smoking habits was obtained from the next-of-kin by questionnaire. None of the occupational exposures that were studied (work with live animal care, in the bleeding area, on the killing floor, or with meat cutting, processing, curing, smoking, chilling and packaging) were associated with an increased lung cancer rate. Tobacco smoking habits may have contributed to the overall excess of lung cancer found previously for this occupational group.

Abattoirs↗

Field potentials evoked in rat primary somatosensory cortex (SI) by impulses in cutaneous A beta- and C-fibres.

A projection of cutaneous C-afferent fibres to the contralateral primary somatosensory cortex (SI) was examined in the halothane-anaesthetized rat. Field potentials evoked by electrical stimulation of the right sural nerve were recorded at the surface of an intracortically within the left SI cortex. A late surface positive potential (latency 110-190 ms, mean 136 ms) was evoked by sural stimulation at a strength that activated A- and C-fibres. A selective anodal block of impulse conduction in A-fibres proximal to the stimulating electrodes showed that impulses in C-fibres generate the late potential also in the absence of a preceding A-fibre input. Stimulation of the sural nerve at two sites caused a shift in latency of the late potential corresponding to a conduction velocity of the primary afferent fibres of less than 1.0 m/s. The distribution of the C-fibre-evoked potential in SI was similar to that of the A beta-fibre evoked 'primary' potential suggesting that the investigated projection of cutaneous C-fibres to SI has a somatotopic organization.

Action Potentials↗

Short-term mortality and cancer incidence in capacitor manufacturing workers exposed to polychlorinated biphenyls (PCBs).

A cohort study of 142 male Swedish capacitor manufacturing workers was performed. PCB had been used as a dielectricum in power capacitors between 1960 and 1978. Mortality was investigated for the period 1965 to 1982 and cancer incidence from 1965 to 1980. Twenty-one deaths and seven cancers were observed, which was in agreement with the anticipated numbers calculated from national statistics. One person had developed two rare tumors, a slow growing mesenchymal tumor (desmoid) and a malignant lymphoma. The results cannot rule out the possibility of a carcinogenic risk from PCB exposure because of the small size of the cohort and relatively brief follow-up period, but they do not indicate any excess mortality or cancer incidence in this factory so far.

Adult↗

Temperature and vibration thresholds in vibration syndrome.

In a study to investigate whether the quantitative assessment of temperature and vibration thresholds can improve the evaluation of the neurological symptoms in vibration syndrome 37 patients with neurological symptoms (paraesthesias, numbness, pain) in the hands who had worked with hand held vibrating tools and 46 healthy controls not exposed to vibration were examined. Temperature thresholds were measured on the thenar eminence and on the volar side of the second and third fingers held together. Vibration thresholds were determined on the dorsum of the hand and on the dorsal side of the second and fifth fingers proximal to the nail. The neutral zone between thresholds for warmth and cold was much wider in the patients than in the controls. Patients older than 45 had higher vibration thresholds than controls. Electroneurography was abnormal in 18 of 34 patients and a carpal tunnel syndrome was diagnosed in six subjects. This investigation is thus indicated in patients with neurological symptoms. Seven of the patients with normal electroneurographic findings had impaired temperature or vibration thresholds or both. Determination of sensory thresholds seems to add valuable information and the methods are, by contrast with electroneurography, easily adapted to the screening of exposed groups outside hospital. Our results indicate that thin myelinated and unmyelinated nerve fibres might be damaged in the vibration syndrome.

Adult↗