Studies of the separation and characterisation of mixtures of starch and cellulose derivatives by use of chromatography and mass spectrometry

In this work a method was developed for characterisation of commercially available polymers consisting of mixtures of substituted cellulose and starch. Selective hydrolysis with specific enzymes was used to achieve separation of the two polymers in the mixture. Enzymes hydrolysing (1-->4)-alpha-D and (1-->6)-alpha-D-glycosidic bonds were used for the starch part and enzymes hydrolysing (1-->4)-beta-D-glycosidic bonds for the cellulose part. The hydrolysed fraction was separated from the unhydrolysed fraction and characterised by use of size-exclusion chromatography (SEC), to confirm that enzyme hydrolysis of the different polymers had occurred. High-performance anion-exchange chromatography (HPAEC) was performed to determine the amount of unmodified glucose units (UGU) in the fractions. Electrospray ionisation mass spectrometry (ESIMS) was used for determination of the substituents. All products were converted to monomers by acid hydrolysis to simplify mass spectral identification of the substituents. The monomers were further subjected to acetylation with acetic acid anhydride to facilitate identification of the substituents. By combining the results from the different analytical techniques a picture of the samples was obtained.

Asthma and wheezing symptoms in young people in six Western countries

BACKGROUND

Asthma diagnosed in children shows wide geographical variations. Large scale surveys identify children with diagnosed asthma, but neglect the group of youngsters with multiple asthmatic complaints.

METHODS

A short validated asthma questionnaire was included in six national surveys of the Health Behaviour in School-Aged Children Study. Prevalence rates are presented by country, gender and age. Gender and age differences are analysed using binary and multinomial logistic regressions controlling for age and smoking.

RESULTS

Large country differences are observed in the prevalence rates of diagnosed asthma (8.6%-20.9% in boys, 6.9%-18.5% in girls) and young people with "asthma-like symptoms" (9.6%-20.2% in boys, 9.2%-23.1% in girls). When controlling for age and smoking, significant gender differences are observed (more diagnosed asthma in boys, more asthmatic symptoms in girls). Age differences were observed in adolescents with "asthma-like symptoms", but not in diagnosed asthma.

CONCLUSIONS

Using a short asthma questionnaire, large differences in diagnosed asthma and wheezing symptoms are observed between the countries. A considerable group of youngsters with "asthma-like symptoms" is detected in all countries, and may be an unrecognised risk group in health promotion.

Oscillating Bubble SHG on Surface Elastic and Surface Viscoelastic Systems: New Insights in the Dynamics of Adsorption Layers

Surface rheology governs a great variety of interfacial phenomena such as foams or emulsions and plays a dominant role in several technological processes such as high-speed coating. Its major difference with bulk rheology resides in the high compressibility of the surface phase, which is the direct consequence of the molecular exchange between adsorbed and dissolved species. In analogy to bulk rheology, a complex surface dilational modulus, epsilon, which captures surface tension changes upon defined area changes of the surface layer, can be defined. The module epsilon is complex, and the molecular interpretation of the dissipative process that gives rise to the imaginary part of the module is subject to some controversy. In this contribution, we used the oscillating bubble technique to study the surface dilational modulus in the mid-frequency range. The dynamic state of the surface layer was monitored by a pressure sensor and by surface second-harmonic generation (SHG). The pressure sensor measures the real and imaginary part of the modulus while SHG monitors independently the surface composition under dynamic conditions. The experiment allows the assessment of the contribution of the compositional term to the surface dilational modulus epsilon. Two aqueous surfactant solutions have been characterized: a surface elastic and a surface viscoelastic solution. The elastic surface layer can be described within the framework of the extended Lucassen-van den Tempel Hansen model. The change in surface concentration is in phase with the relative area change of the surface layer, which is in strong contrast with the results obtained from the surface viscoelastic solution. Here, surface tension, area change, and surface composition are phase-shifted, providing evidence for a nonequilibrium state within the surface phase. The data are used to assess existing surface rheology models.

Respiratory symptoms and 30 year mortality from obstructive lung disease and pneumonia

BACKGROUND

As little is known about the long term relationship between respiratory symptoms and mortality from non-malignant respiratory diseases, a study was undertaken to investigate the predictive value of respiratory symptoms and symptom load for mortality from obstructive lung disease (OLD) and pneumonia in the long term in a Norwegian population.

METHODS

In 1972, 19 998 persons aged 15-70 years living in Oslo were randomly selected for a respiratory survey. The response rate was 89%. All were followed for 30 years. The association between cough, asthma-like symptoms, two levels of dyspnoea on exercise, a symptom score, and mortality from OLD and pneumonia were investigated separately for men and women by multivariable analyses, with adjustment for age, occupational exposure to air pollution, and smoking habits.

RESULTS

OLD accounted for 43% and pneumonia for 50% of all deaths from respiratory causes. In men the hazard ratio for mortality from OLD varied from 4.0 (95% confidence interval (CI) 2.4 to 6.5) for cough to 9.6 (95% CI 5.1 to 18.3) for severe dyspnoea, and in women from 5.1 (95% CI 2.3 to 11.3) for moderate dyspnoea to 13.0 (95% CI 6.0 to 28.3) for severe dyspnoea. The symptom score was strongly predictive of death from OLD in a dose-response manner.

CONCLUSIONS

There is a significant, positive, strong association between respiratory symptoms and 30 year mortality from OLD. The association between respiratory symptoms and mortality from pneumonia is weaker and not significant.

Respiratory symptoms as predictors of all-cause mortality in an urban community: a 30-year follow-up

OBJECTIVE

We investigated the relationship between respiratory symptoms and mortality from all causes in a large Norwegian population. We also examined mortality during separate periods of follow-up.

DESIGN

Population-based, prospective cohort study.

SETTING AND SUBJECTS

A total of 19,998 men and women were randomly selected from the general population of Oslo. They received a postal respiratory questionnaire. The response rate was 88%.

MAIN OUTCOME MEASURES

The relationship between 11 respiratory symptoms and 30 years of total mortality was investigated separately for men and women by multivariate analyses with adjustment for age, smoking habits and occupational exposure to air pollution.

RESULTS

The relative mortality risk in comparison with asymptomatic subjects varied from 1.36 (95% confidence interval 1.25-1.48) for cough symptoms to 2.46 (2.13-2.85) for severe dyspnoea amongst men; the corresponding rates amongst women were 1.28 (1.16-1.40) and 1.52 (1.31-1.75), respectively. The relative risk of mortality in individuals with 1-3, 4-6 and 7 or more symptoms was 1.20, 1.60 and 2.53 (P for trend 0.000) in men and 1.14, 1.47 and 1.84 (P for trend 0.000) in women. Except for cough, the mortality rates associated with respiratory symptoms decreased significantly during follow-up. The positive association between respiratory symptoms and mortality was observed in people with and without cardiopulmonary diseases.

CONCLUSIONS

Respiratory symptoms were significant predictors of mortality from all causes over 30 years, decreased during follow-up and were still increased after 30 years.

Lung fibre burden in lung cancer cases employed in the rock and slag wool industry

OBJECTIVES

To evaluate the relationship between estimated exposure to man-made vitreous fibres (MMVF) and to asbestos fibres and their concentration in the lung tissue of lung cancer cases amongst MMVF production workers.

METHODS

Retrospective retrieval of available lung tissue specimens was conducted following a case-control study that assessed estimated occupational exposures of MMVF workers. Fibre recovery and analysis by transmission electron microscopy (TEM) were conducted to determine fibre type, fibre dimension and numbers per gram of dry lung tissue. For cases with detailed exposure data, geometric mean (GM) concentrations were compared across the exposure categories, and regression models were used to investigate the relationship between the lung fibres and the variables of estimated exposure, with and without additional variables that may affect fibre retention.

RESULTS

A total of 24 samples from 17 cases of lung cancer were available for analysis: MMVF were detected in all cases. Asbestos fibres were detected in 16. No difference or trend in GM MMVF concentration was observed across the estimated exposure categories. Odds ratio (OR) for MMVF g(-1) dry lung was 0.5 (95% confidence interval: 0.1-2.4) for the second, and 3.5 (0.6-18.9) for the third quartile of index of average exposure to MMVF in industry, compared with the first (lowest exposed) quartile (no cases in the highest quartile).

CONCLUSIONS

No observable relationship existed between estimated exposure and directly-measured lung fibres among this sample of cases. Retrospective specimen collection, intra-individual variability in fibre concentration, effect of unknown factors on fibre retention and small sample size militated against this study providing evidence for or against a relationship between estimated exposure and lung fibre concentrations.

Girls with anorexia nervosa as young adults. Self-reported and parent-reported emotional and behavioural problems compared with siblings

This follow-up study had three objectives: 1) to investigate emotional and behavioural problems, adaptive functioning and substance use in former anorexia nervosa (AN) patients compared with siblings, 2) to compare information obtained from different informants, and 3) to compare questionnaire results with interview results. Fifty (of 55) female AN patients, representative for AN patients under 18 years referred to county health services, were assessed at a mean of 8.8 years after treatment start with the Young Adult Self-Report and the Young Adult Behaviour Checklist (mean age 23.1 years). In all, 48 patients, 25 siblings, 33 mothers and 27 fathers participated in the questionnaire study. Although 41/50 (82 %) had recovered from their eating disorder, the former AN patients had substantially more self-reported and parent-reported problems than their siblings, particularly with regard to Internalising Problems and on the Anxious/Depressed syndrome scale. Cross-informant agreement between the parents and between parents and patients was high, but low between parents and siblings. The patients with psychiatric diagnoses at follow-up had substantially higher problem scores than those without diagnoses both on the self-report and the parent-report, supporting the validity of the questionnaires. In conclusion, the self- and parent-reports showed a high level of Internalising Problems and were useful instruments in the assessment of former AN patients.

Second primary cancers among 109 000 cases of non-Hodgkin's lymphoma

An analysis of other primary cancers in individuals with non-Hodgkin's lymphoma (NHL) can help to elucidate this cancer aetiology. In all, 109 451 first primary NHL were included in a pooled analysis of 13 cancer registries. The observed numbers of second cancers were compared to the expected numbers derived from the age-, sex-, calendar period- and registry-specific incidence rates. We also calculated the standardised incidence ratios for NHL as a second primary after other cancers. There was a 47% (95% confidence interval 43–51%) overall increase in the risk of a primary cancer after NHL. A strongly significant (P<0.001) increase was observed for cancers of the lip, tongue, oropharynx^*, stomach, small intestine, colon^*, liver, nasal cavity^*, lung, soft tissues^*, skin melanoma^*, nonmelanoma skin^*, bladder^*, kidney^*, thyroid^*, Hodgkin's lymphoma^*, lymphoid leukaemia^* and myeloid leukaemia. Non-Hodgkin's lymphoma as a second primary was increased after cancers marked with an asterisk. Patterns of risk indicate a treatment effect for lung, bladder, stomach, Hodgkin's lymphoma and myeloid leukaemia. Common risk factors may be involved for cancers of the lung, bladder, nasal cavity and for soft tissues, such as pesticides. Bidirectional effects for several cancer sites of potential viral origin argue strongly for a role for immune suppression in NHL.

Second primary malignancies in patients with male breast cancer

An international multicentre study of first and second primary neoplasms associated with male breast cancer was carried out by pooling data from 13 cancer registries. Among a total of 3409 men with primary breast cancer, 426 (12.5%) developed a second neoplasia; other than breast cancer, a 34% overall excess risk of second primary neoplasia, affecting the small intestine (standardised incidence ratio, 4.95, 95% confidence interval, 1.35–12.7), rectum (1.78, 1.20–2.54), pancreas (1.93, 1.14–3.05), skin (nonmelanoma, 1.65, 1.16–2.29), prostate (1.61, 1.34–1.93) and lymphohaematopoietic system (1.63, 1.12–2.29). A total of 225 male breast cancers was recorded after cancers other than breast cancer, but an increase was found only after lymphohaematopoietic neoplasms. BRCA2 (and to some extent BRCA1) mutations may explain the findings for pancreatic and prostate cancers. Increases at other sites may be related to unknown factors or to chance. This large study shows that the risks for second discordant tumours after male breast cancer pose only a moderate excess risk.

Good outcome of adolescent onset anorexia nervosa after systematic treatment. Intermediate to long-term follow-up of a representative county-sample

We studied the intermediate to long-term outcome of childhood and adolescent onset anorexia nervosa (AN), in a sample that had received systematic treatment based on close cooperation between parents, paediatric department and child and adolescent psychiatry. Of 55 female AN-patients, 51 were examined 3.5-14.5 years after treatment start. The material includes all AN-patients under 18 years in one county that received inpatient treatment and almost all that received outpatient treatment, during the time period 1986-1998. Forty-two (82%) subjects had no eating disorder (ED) at follow-up, one (2%) had AN, one (2%) bulimia nervosa (BN) and seven (14%) had less severe ED (EDNOS). Except the one with BN, none had bulimic symptoms. There was no mortality. Twenty (41%) had one or more other axis-1 psychiatric diagnoses at follow-up. Depression and anxiety disorders were most frequent. Psychosocial functioning assessed by Global Assessment of Functioning (GAF) was fairly good; mean 73+/-SD14 for symptoms and mean 77+/-SD13 for functioning. Only 48% were satisfied with life, compared to 83% in a normal population sample. Our conclusion is that the eating disorder outcome was good. However, in accordance with other studies, many subjects had other psychiatric problems at follow-up.

Incidence of Lip Cancer in the Male Norwegian Agricultural Population

OBJECTIVE

To explore lip cancer (LC) associations with work environmental exposures in a record-linkage study of Norwegian farmers. We hypothesize immunosuppressive substances (e.g. mycotoxins, pesticides) to influence LC incidence.

METHODS

A cohort of 131,243 male Norwegian farmers born 1925-1971 was established by cross-linkage of national registers and followed up through 1999 for incident LC, (ICD-7 site 140) in the Cancer Registry of Norway. Farm production data from agricultural censuses 1969-1979 and meteorological data on solar radiation and fungal forecasts (events of wet and temperate conditions known to favour fungal growth and mycotoxin formation) served as exposure proxies. Adjusted rate ratios (RR) and 95% confidence intervals (CI) were estimated using Poisson regression.

RESULTS

We identified 108 LC cases (rate 4.4 per 100,000 person-years). We found LC to be moderately associated with horses on the farm (RR = 1.6, CI = 1.0-2.4), construction work employment (RR = 1.7, CI = 1.1-2.6), pesticide use (RR = 0.7, CI = 0.4-1.0), grain production (RR = 1.3, CI = 0.9-2.1) and increasing levels of fungal forecasts (RR = 1.6, CI = 0.9-2.8 in the highest two quartiles).

CONCLUSION

Moderate associations of LC with grain production and fungal forecasts and the negative association with pesticide could possibly be explained by exposure to immunosuppressive mycotoxins. Some of the associations observed could be explained by solar exposure.

Mortality and cancer incidence among Lithuanian cement producing workers

AIMS

To investigate mortality and cancer incidence of cement producing workers.

METHODS

A total of 2498 cement workers who have been employed at Portland cement producing departments for at least one year from 1956 to 2000 were followed up from 1 January 1978 to 31 December 2000. The cohort contributed 43,490 person-years to the study. Standardised incidence ratios (SIR) and standardised mortality ratios (SMR) were calculated as ratios between observed and expected numbers of cancers and deaths. The expected numbers were based on sex specific incidence and mortality rates for the total Lithuanian population.

RESULTS

Significantly increased SMRs were found for all malignant neoplasms (SMR 1.3, 95% CI 1.0 to 1.5) and for lung cancer (SMR 1.4, 95% CI 1.0 to 1.9) among male cement workers. SIR for all cancer sites was 1.2 (95% CI 1.0 to 1.4). Excess risk was found for cancer of the lung (SIR 1.5, 95% CI 1.1 to 2.1). The SIR for urinary bladder cancer was also increased (SIR 1.8, 95% CI 0.9 to 3.5). The overall cancer incidence was not increased among females (SIR 0.8, 95% CI 0.6 to 1.1). With increasing cumulated exposure to cement dust, there were indications of an increasing risk of lung and stomach cancers among males.

CONCLUSIONS

This study supported the hypothesis that exposure to cement dust may increase the lung and bladder cancer risk. A dose related risk was found for stomach cancer, but no support was found for an increased risk of colorectal cancer.

Experimental and CFD evidence of multiple solutions in a naturally ventilated building

This paper considers the existence of multiple solutions to natural ventilation of a simple one-zone building, driven by combined thermal and opposing wind forces. The present analysis is an extension of an earlier analytical study of natural ventilation in a fully mixed building, and includes the effect of thermal stratification. Both computational and experimental investigations were carried out in parallel with an analytical investigation. When flow is dominated by thermal buoyancy, it was found experimentally that there is thermal stratification. When the flow is wind-dominated, the room is fully mixed. Results from all three methods have shown that the hysteresis phenomena exist. Under certain conditions, two different stable steady-state solutions are found to exist by all three methods for the same set of parameters. As shown by both the computational fluid dynamics (CFD) and experimental results, one of the solutions can shift to another when there is a sufficient perturbation. These results have probably provided the strongest evidence so far for the conclusion that multiple states exist in natural ventilation of simple buildings. Different initial conditions in the CFD simulations led to different solutions, suggesting that caution must be taken when adopting the commonly used 'zero initialization'.

Anatomy of a bathtub vortex

We present experiments and theory for the "bathtub vortex," which forms when a fluid drains out of a rotating cylindrical container through a small drain hole. The fast down-flow is found to be confined to a narrow and rapidly rotating "drainpipe" from the free surface down to the drain hole. Surrounding this drainpipe is a region with slow upward flow generated by the Ekman layer at the bottom of the container. This flow structure leads us to a theoretical model similar to one obtained earlier by Lundgren [J. Fluid Mech. 155, 381 (1985)]], but here including surface tension and Ekman upwelling, comparing favorably with our measurements. At the tip of the needlelike surface depression, we observe a bubble-forming instability at high rotation rates.

Follow-up of radio and telegraph operators with exposure to electromagnetic fields and risk of breast cancer

It is still unclear whether exposure to electromagnetic fields (EMF) is associated with breast cancer. To further investigate the issue, we followed-up a cohort of Norwegian female radio and telegraph operators in the period 1 January 1961 to 31 May 2002, with 99 breast cancer cases. The standardized incidence ratio (SIR) for breast cancer was 1.30 (95% confidence intervals (CI) 1.05-1.58), compared with the total Norwegian female population. In a subsequent nested case-control study, exposure to radio frequency (405 kHz-25 MHz) and extremely low-frequency (50 Hz) fields due to stay in the radio room during day and night was cumulated by years of employment and workload according to ship type. The exposure was assessed in two age groups (<50, 50+) with regard to risk of breast cancer. The odds ratios in the group with the highest cumulative exposure were 1.78 (95% CI 0.59-5.41) and 2.37 (95% CI 0.88-6.36) in the younger and the older women, respectively. P-value for trend was 0.03 in both age groups. The results of the oestrogen receptor status analysis by exposure to EMF showed an increased risk of oestrogen receptor-positive breast cancer in the younger women, while the older age group had an elevated risk of oestrogen receptor-negative breast cancer. Thus, the present study contributes to the hypothesis of an association between occupational exposure to EMF and increased risk of breast cancer.

Long-term changes in adult asthma prevalence

There has been an increase in asthma prevalence among children. Little evidence is available regarding long-term changes in asthma prevalence in adults. Two cross-sectional studies were performed among adults aged 15-70 yrs in Oslo, Norway, in 1972 and again in 1998-1999 (n=39,998). A postal self-completed questionnaire was used. Exactly the same questions and survey methods were used in both studies. In 1998-1999, additional telephone follow-up was included for postal nonresponders. The crude prevalence of ever having had a doctor's diagnosis of asthma increased from 3.4 to 9.3%. The prevalence of wheezing increased from 17.8 to 25.8% and attacks of breathlessness from 12.6 to 16.7%. After controlling for smoking, the risk of asthma among those aged <40 yrs had tripled. The increase in asthma was 50% greater in females than males. The prevalence of symptoms increased less than asthma diagnosis. Wheezing increased by 50% in those aged <40 yrs, with smaller increases at greater ages. The increase in symptoms was seen among both asthmatics and nonasthmatics. There has been a large increase in the prevalence of asthma diagnosis and asthma-like symptoms in adults. The increase is less pronounced among those aged >40 yrs.

Long-term risk of second malignancy after treatment of Hodgkin's disease: the influence of treatment, age and follow-up time

BACKGROUND

To quantify the long-term risk of second cancers (SCs) up to 30 years after primary treatment for Hodgkin's disease (HD) Material and methods In the period 1968 to 1985, an unselected population of 1024 patients started treatment for HD at the Norwegian Radium Hospital (NRH) and were followed for SC from 1969 through 1998 by The Norwegian Cancer Registry. The median age at diagnosis of HD was 40 years, and the median time at follow-up was 14 years.

RESULTS

Of 197 SCs, 14 were acute non-lymphocytic leukemia (ANLL), 31 non-Hodgkin's lymphoma (NHL) and 152 solid cancers. The standardized incidence ratio (SIR) was significantly increased for SCs as a group, and for the subgroups ANLL, NHL, lung cancer, breast cancer, stomach cancer and melanoma. ANLL was related to heavy treatment with chemotherapy (CT) and combined CT and radiotherapy (RT), NHL was not treatment related, and solid tumors were related to radiotherapy only or combined RT and CT. The SIR of ANLL and NHL reached a peak between 5 and 10 years after treatment. Solid and non-solid tumors increased with young age at diagnosis of HD and solid tumors increased with follow-up time up to 28 years

CONCLUSION

In a long-term follow-up study of HD patients of all ages, the SIR of solid tumors was high in patients treated at young age and decreased with increasing age. Most solid tumors had started within or at the edge of the irradiated field, and SIR of solid tumors increased even 20-30 years after diagnosis.

Medicinal plants used by Luo mothers and children in Bondo district, Kenya

In a follow-up to studies of school-children's medical knowledge among the rural Luo of western Kenya, seven mothers were asked for their knowledge of plant medicine, and the 91 plant remedies mentioned by them were collected, 74 of these remedies were identified as 69 different species (in 13 cases, the material did not allow identification of the species, in two cases, only the family could be identified, and in two, not even this was possible). The results of this survey and some comments on Luo illness concepts are presented below and briefly discussed in relation to the earlier work on school-children and to another survey of Luo plant medicine in the same district. The article concludes that the consensual core of Luo plant medicine is known by ordinary mothers and their children as well as by recognised healers. It is a shared resource, that is used by women, mainly in the care for their children, and it is not an expert domain of knowledge, as is often, in studies of herbal or 'traditional' medicine are studied. The medicinal plants, upon which many mothers as well as healers agree should be examined further pharmacologically in order to assess their efficacy against the common infectious and parasitic diseases found in this area of western Kenya.

No association between human parvovirus B19 and testicular germ cell cancer

The incidence of testicular germ cell cancer, which is the most common cancer among young male adults, is increasing. The aetiology remains unknown, although a virus has been proposed. A previous study has shown a high prevalence of human parvovirus B19 (B19) DNA in the testes of patients with testicular germ cell tumours (85%) and suggested that B19 may play a role in tumour development. To address this question of causality, seroreactivity to B19 was studied among cases (n=80) and controls (n=241) using serum samples drawn before the onset of disease, in addition to an elucidation of the frequency of virus DNA in a retrospectively collected 2-year testicular carcinoma series. No association was found between B19 seropositivity and the risk of testicular cancer (odds ratio=1.03; 95% confidence interval=0.60-1.77) nor was there any dose-response relation (P for trend=0.53). This study did, however, confirm the observation that B19 DNA can be detected in testicular carcinoma tissue, as 4 of 24 cases were found to be positive, while no B19 DNA could be detected in the control cases. It is speculated that this finding may be due to susceptibility of the carcinoma cells to B19 virus owing to high-level expression of the viral receptor glycosphingolipid (Gb4) and possible other putative cellular factors resulting in a localized persistence initiated after the development of cancer.

Non-malignant mortality among Norwegian silicon carbide smelter workers

OBJECTIVES

To investigate associations between exposures in the silicon carbide (SiC) industry and mortality from non-malignant diseases.

METHODS

Mortality among 2562 men, working in one of three silicon carbide smelters was investigated, giving 52,618 person-years of follow up from 1962 to 1996. Dose-response relations were investigated by internal comparisons using Poisson regression and by stratified standardised mortality ratio (SMR) analyses.

RESULTS

Mortality from all causes was significantly raised compared with the Norwegian mortalities among men, SMR=1.12, (95% confidence interval (95% CI) 1.05 to 1.20). An excess mortality from asthma, emphysema, and chronic bronchitis combined was found, SMR=2.21 (95% CI 1.61 to 2.95), increasing from 1.05 in the unexposed category to 2.64 (95% CI 1.44 to 4.43) in the upper category of exposure to total dust. The Poisson regression analysis confirmed the results from the stratified SMR analyses, and suggested that smoking did not act as a confounder. No association was found for circulatory mortality.

CONCLUSIONS

There was an increased mortality from asthma, emphysema, and chronic bronchitis combined among SiC workers exposed to dust.

Pharmacological MRI mapping of age-associated changes in basal ganglia circuitry of awake rhesus monkeys

While the pathophysiological changes induced by the loss of dopamine innervation in the basal ganglia by Parkinson's disease (PD) are well studied, little is known about functional changes in the neural circuitry of this area during normal aging. Here we report the first survey of age-associated changes in the basal ganglia of behaviorally characterized, awake rhesus monkeys, using pharmacological MRI to map responses to dopaminergic stimulation. Apomorphine, a mixed D(1)/D(2) dopamine receptor agonist, evoked little change in the substantia nigra (SN) of aged animals while significantly reducing activation in young adult monkeys. Compared to young animals, both apomorphine and d-amphetamine (which increases synaptic dopamine levels) significantly increased activation of the aged rhesus globus pallidus externa (GPe). In addition, the aged animals showed decreased activity in the putamen in response to d-amphetamine administration. Although the responses in the SN and putamen of the aged monkeys differed from those in animal models of PD, the apomorphine-evoked activation of their GPe corresponded with apomorphine-induced increases in neuronal activity seen in Parkinson's patients and animal models. Given the major role of the GPe in regulating motor behavior, the altered responses in the aged GPe may contribute significantly to the motor slowing and movement dysfunctions characterizing advanced age.