Neurobehavioral and sensory irritant effects of controlled exposure to a complex mixture of volatile organic compounds

Subjective reactions of discomfort, impaired air quality, irritation of mucosal membranes, and impaired memory have been reported in chemically sensitive subjects during exposure to volatile organic compounds (VOCs) found in new buildings. Sixty-six normal healthy male subjects aged 18-39 were exposed for 2.75 hr to a complex VOC mixture at 0 and 25 mg/m3. Each subject completed control and exposure sessions at one-week intervals in counterbalanced order. Measurements included comfort ratings of eye, nose and throat irritation, symptom questionnaire and computerized behavioral tests. Subjects found the odor of VOCs unpleasantly strong and reported that VOC exposure degraded air quality, increased headache and produced general discomfort. VOC exposure did not affect performance on any behavioral tests.

Reflections on the changing times

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The effect of danazol and the LHRH agonist analogue goserelin (Zoladex) on the biological activity of luteinizing hormone in women with endometriosis

In an attempt to determine whether the suppression in oestradiol levels caused by danazol is due to an effect on the hypothalamic-pituitary axis, we compared the endocrine effects of danazol with those of the LHRH (GnRH) agonist analogue goserelin. Serum levels of immunoreactive LH (I-LH), FSH, 17 beta-oestradiol (E2) and bioactive LH (B-LH) (using a mouse Leydig cell bioassay), were measured in ten and 20 women with endometriosis treated with danazol and goserelin, respectively. I-LH was measured both by radioimmunoassay (RIA) and immunoradiometric assay (IRMA). During 6 months of treatment with 600 mg of danazol daily, mean serum E2 decreased (P less than 0.05) to levels near the upper limit of the post-menopausal range (to a mean (and 95% confidence interval of the mean) of 117 (65-169) pmol/l) whereas FSH, I-LH (both by RIA and IRMA) and B-LH levels were not significantly altered. During 6 months of treatment with monthly depot injections of 3.6 mg goserelin, mean serum E2 decreased (P less than 0.001) to well within the post-menopausal range (to 23 (18-28) pmol/l). The mean FSH, I-LH and B-LH levels also decreased (P less than 0.05) during therapy with goserelin (from 3.9 (3.1-4.7) to 2.0 (1.6-2.4) IU/l for FSH, from 5.3 (4.5-6.1) to 1.9 (1.7-2.1) IU/l for RIA-LH, from 2.9 (2.5-3.3) to less than 0.5 (less than 0.5) IU/l for IRMA-LH and from 9.1 (7.1-11.1) to 2.9 (2.6-3.2) IU/l for B-LH).(ABSTRACT TRUNCATED AT 250 WORDS)

British perspective on the U.S. Preventive Services Task Force guidelines

The clinical approach to prevention, cogently documented in the Task Force guidelines, implies the medicalization of prevention. The concentration of resources on those most in need is efficient, the widening of physicians' responsibility is welcome, and the influence on the recipients diffuses into the community. The Task Force report, however, fails to stress the problems and the limitations of this approach. The adverse effects of "labeling" can be serious. They need to be measured and taken into account, and there should be no screening without counseling and long-term care; the latter cannot be guaranteed unless there is a comprehensive general practitioner system. Screening readily generates overmedication, particularly since many physicians lack the skills, the inclination, or the staff to provide expert and continuing health advice. Concern for high-risk individuals should be only one part of a much wider preventive strategy. This is illustrated by the close correlations between the prevalence of high-risk status and the population mean value (0.85 for hypertension vs. mean blood pressure, 0.97 for excess use of alcohol vs. population mean intake). The medical approach, important though it is, must not distract attention from the more fundamental population strategy of prevention.

Blood lead concentration, renal function, and blood pressure in London civil servants

Blood lead concentration was measured in 398 male and 133 female London civil servants not subject to industrial exposure to heavy metals. The relation between blood lead and serum creatinine concentrations and blood pressure were examined. Blood lead concentration ranged from 0.20 to 1.70 mumol/l with a geometric mean concentrations of 0.58 mumol/l in men and 0.46 mumol/l in women (p less than 0.001). In women blood lead concentration increased with age (r = +0.27; p = 0.002). In the two sexes blood lead concentration was positively correlated with the number of cigarettes smoked a day (men r = +0.17 and women r = +0.22; p less than or equal to 0.01), with the reported number of alcoholic beverages consumed a day (men r = +0.34 and women r = 0.23; p less than 0.01), and with serum gamma-glutamyltranspeptidase (men r = +0.23 and women r = +0.14; for men p less than 0.01). Blood lead concentration was not correlated with body weight, body mass index, and employment grade. In men 14% of the variance of blood lead concentration was explained by the significant and independent contributions of smoking and alcohol intake and in women 16% by age, smoking, and alcohol consumption. In men serum creatinine concentration tended to rise by 0.6 mumol/l (95% confidence interval from -0.2 to +1.36 mumol/l) for each 25% increment in blood lead concentration. In men and women the correlations between blood lead concentration and systolic and diastolic blood did not approach statistical significance. In conclusion, in subjects not exposed to heavy metals at work gender, age, smoking, and alcohol intake are determinants of blood lead concentration. At a low level of exposure, lead accumulation may slightly impair renal function, whereas blood pressure does not seem to be importantly influenced. Alternatively, a slight impairment of renal function may give rise to an increase in blood lead concentration.

Blood cadmium in London civil servants

Blood cadmium was measured in 466 randomly selected London civil servants not exposed to heavy metals at work. Blood cadmium ranged from 3.6 to 75.6 nmol/L (0.4 to 8.5 micrograms/L) with a geometric mean of 6.4 nmol/L (0.7 micrograms/L) in nonsmokers and 13.6 nmol/L (1.5 micrograms/L) in smokers (p less than 0.001). Blood cadmium was higher in women than in men (9.5 versus 7.8 nmol/L) and was inversely correlated with employment grade (p less than 0.001). The associations with age, body weight and alcohol intake were not significant. After adjusting for gender and the number of cigarettes smoked per day, 36% of the variance of blood cadmium was explained, while the contribution of employment grade was not significant. There was an unexpected negative relationship between serum creatinine and blood cadmium in men (r = -0.16; p less than 0.01). This was not true in women (r = +0.03), but the correlation remained present in men after adjustment for age, body mass index and smoking. In contrast, in the two sexes, the correlations between blood pressure and blood cadmium were weak and not statistically significant. In conclusion, in unexposed subjects, gender and smoking are important determinants of blood cadmium. In addition, a low level of environmental exposure to cadmium is not associated with a deterioration of renal function or an increase in blood pressure.

Prepartum psychosis

Four patients are described who suffered from postpartum psychosis, and also from similar episodes starting in late pregnancy. It is argued that these patients provide evidence for the prepartum onset of postpartum psychosis in a small minority of patients. The relevance of this to the aetiology of puerperal psychosis is discussed.

The Kenyan Luo migration study: observations on the initiation of a rise in blood pressure

OBJECTIVE

To demonstrate the magnitude, timing, and cause of changes in blood pressure that occur in migrants from a low blood pressure population on moving to an urban area.

DESIGN

A controlled longitudinal observational study of migrants as soon after migration as possible and follow up at three, six, 12, 18, and 24 months after migration. A cohort of controls living in a rural area who were matched for age, sex, and locality were also observed at the same periods.

SETTING

35 Villages on the northern shores of Lake Victoria in western Kenya and Nairobi.

PARTICIPANTS

325 Members of the Luo tribe aged 15 to 34 years who had migrated to Nairobi and 267 controls living in villages. The numbers of both groups reduced during follow up such that only 63 migrants and 143 controls were followed up for two years.

MAIN OUTCOME MEASURES

A medical questionnaire and three 24 hour diet histories were completed by migrants and controls. Height, weight, pulse, and blood pressure were measured. Three 12 hour overnight urine samples were collected from all participants and analysed for sodium, potassium, and creatinine concentrations.

RESULTS

The mean systolic blood pressure of migrants was significantly higher than that of controls throughout the study, and the distribution of blood pressure was shifted to the right compared with controls. The mean diastolic blood pressure of the two groups diverged over time. Blood pressure differences were not due to selective migration. The migrants' mean urinary sodium:potassium ratio was higher than that of controls (p less than 0.001) throughout, and weight and pulse rate were also higher among migrants, although differences diminished with time.

CONCLUSIONS

Urinary sodium:potassium ratio, pulse rate, and weight are important predictors of increased blood pressure among migrants from a low blood pressure community and may also be implicated in the initiation of essential hypertension.

Effects of coronary risk reduction on the pattern of mortality

Control of coronary risk factors is associated with lower age-specific risks, but people will then live longer, with increased exposure to the higher mortality rates of the elderly. Expected changes in pattern of mortality, based on the 15-year follow-up of men in the Whitehall study, have been calculated. Non-smokers live longer than smokers, but death (when it comes) is more likely to be due to heart attack and less likely to be due to cancer. By contrast a lower level of plasma cholesterol, which is also associated with longer life, is expected to reduce the lifetime risk of fatal heart attack, its place then being taken by a typical mixture of other causes of death.

Post-translational polymorphism of human IgA identified by immunoisoelectrofocusing

Immunoisoelectrofocusing (IIEF) reveals a microheterogeneity of human serum IgA controlled by an autosomal polymorphic gene, termed S. The microheterogeneity disappears when sialic acid is removed from serum glycoproteins by neuraminidase treatment. It can be postulated, therefore, that S encodes a sialyltransferase which attaches sialic acid at the outer prosthetic chains of IgA.

Predictors of relatives' attendance at a state hospital workshop on schizophrenia

A prospective research design was used to identify patient and family variables that would predict relatives' attendance at an educational workshop on schizophrenia at a state psychiatric hospital. Data were collected from patient charts and telephone interviews with relatives. Thirty-two percent of the 84 invited relatives attended the workshop. Significant predictors of attendance included relatives' proximity to the hospital, previous number of visits with the patient, knowledge about schizophrenia, and familiarity with the National Alliance for the Mentally Ill. The findings suggest that a substantial proportion of relatives of the seriously mentally ill desire information and help in coping with their ill family member. Relatives' participation might be further increased by conducting workshops at more convenient sites and encouraging attendance by those less knowledgeable about schizophrenia.

Preventive cardiology: what lies ahead?

Despite increased knowledge of the leading causes of cardiovascular diseases, we continue to observe rather than to control the rise and fall of their incidence. Research needs to be more oriented toward current uncertainties of policy: Is a high-fat diet acceptable so long as its polyunsaturated to saturated fat ratio is high? What are the long-term adverse effects of the powerful new cholesterol-lowering drugs? Should people eat more polyunsaturates? Can new understanding of clotting factors help to prevent heart attacks? How can we lower the average blood pressure of the population as a whole? How do maternal and child health influence the next generation's cardiovascular health? The new research to answer such questions requires that epidemiologists abandon the "black box" approach (which ignores mechanisms); instead, basic scientists need to explain the actions of environmental agents. A new style of preventive clinical practice is emerging, but its future success depends on changes in the medical care system (involving structure, rewards, and staffing), changes in medical education, and on the willingness of physicians to negotiate shared responsibility with their patients. Physicians can identify and help high-risk individuals; but because the incidence of heart disease depends on how people live, it follows that progress in prevention ultimately depends on social, economic, and political decisions. By successful communication of knowledge and impartial advice, physicians can assist in those decisions.

INTERSALT study findings. Public health and medical care implications

INTERSALT found a significant association between 24-hour urine sodium excretion and systolic blood pressure in individuals. There was also a significant association between sodium and slope (increase) of blood pressure with age across population samples. The weight of evidence from animal-experimental, clinical, intervention, and epidemiological data favors a causal relation. INTERSALT data from 52 centers in 32 countries permit an estimate of effect on average population blood pressure of lower sodium intake. Based on the sodium-blood pressure association in individuals, it was estimated that a habitual population sodium intake that was lower by 100 mmol/day (e.g., 70 vs. 170 mmol/day) would correspond to an average population systolic pressure that was lower by at least 2.2 mm Hg. This size difference in systolic blood pressure in major US and UK population studies is associated with 4% lower risk of coronary death and 6% lower risk of stroke death in middle age. If habitual diet is both lower in sodium and higher in potassium with lower alcohol intake and less obesity, INTERSALT data estimate average population systolic pressure would be lower by 5 mm Hg. This was calculated to correspond to a 9% lower risk of coronary death and a 14% lower risk of stroke death. INTERSALT cross-population data also suggest that, with a 100 mmol/day lower sodium intake over the life span, the average increase in population systolic pressure from age 25 to 55 years would be less by 9 mm Hg, corresponding at age 55 to a 16% lower risk of subsequent coronary death and 23% lower risk of stroke death.(ABSTRACT TRUNCATED AT 250 WORDS)

Restriction fragment length polymorphism of human mitochondrial DNA in a sample population from Apulia (southern Italy)

Restriction fragment length polymorphism (RFLP) of human mitochondrial DNA was analysed in a sample of 87 subjects from Apulia (South Italy) by the restriction enzymes HpaI, BamHI, HaeII, MspI, AvaII, and HincII using total blood cell DNA probed by human mtDNA from placenta. Five BamHI morphs were observed, two of which are new (BamHI-4 and -5), as well as one new AvaII morph (AvaII-28). The association BamHI-4/AvaII-28 enables us to demonstrate for the first time two polymorphic BamHI sites present together in the same mtDNA molecule. In agreement with historical data the Apulian sample has been shown to be the most heterogeneous Italian population so far tested.

The INTERSALT study: background, methods and main results. INTERSALT Co-operative Research Group

The INTERSALT study used standardised methods to assess the relations of electrolyte intake and blood pressure, taking account of confounding variables, in samples of men and women aged 20-59 drawn from defined populations in 52 centres and 32 countries (10,079 individuals). Sodium excretion was significantly related to blood pressure in individuals. Corrected estimates (probably still too low) indicated, on multiple regression, that a difference of 100 mmol/day in average population sodium intake corresponded to 2.2 mmHg lower systolic pressure. Sodium excretion across centres, with median levels ranging from 0.2 to 242 mmol/24 hour, was related to slope of blood pressure with age, less consistently to median centre pressure. Estimates indicated that a 100 mmol/day lower sodium intake was associated with a 9 mmHg lower rise of systolic pressure between ages 25 and 55. Hypertension was virtually absent in four populations with very low sodium intake, and blood pressure in these samples was not higher at older ages. Potassium intake of individuals was negatively and significantly associated with blood pressure independently of other variables; body mass index and high alcohol intake were strongly positively and independently associated with blood pressure in individuals.

Salt and blood pressure: a community trial

The effect of a health education programme on salt reduction and blood pressure was studied in two matched rural communities in Portugal, each of about 800 adult inhabitants. Initial salt intake was high (about 360 mmol/person/day) and 30% of persons were hypertensive (DBP 95 mmHg or above). In the intervention community average blood pressure fell by 3.6/5.0 mmHg at one year and 5.0/5.1 mmHg at two years, due to a general distribution shift. In the control community diastolic pressures remained stable and systolic pressures rose. The difference in trends between the two communities was highly significant. There were also significant correlations within individuals in the intervention community between fall in blood pressure and fall in urinary sodium/creatinine ratio. At least in this high-intake population a fall in salt consumption seems to have caused an important fall in average blood pressure.

Epidemiology of acute asthma: IgE antibodies to common inhalant allergens as a risk factor for emergency room visits

In recent years the morbidity and mortality of asthma has increased, although the etiology is still poorly understood. Most patients with asthma suffer acute attacks that are commonly treated in hospital emergency rooms (ER). In the present study, asthma in adults was studied with acute attacks as a marker for the disease; 102 patients first observed at a university hospital ER with acute airway obstruction were compared to 118 patients observed at the same ER with any diagnosis other than shortness of breath to evaluate allergy as a risk factor for asthma in adults. Sera were assayed for IgE antibody (Ab) to dust mites, cockroach, cat dander, and grass and ragweed pollen. The results demonstrate that in adults younger than 50 years of age, the prevalence of IgE Abs was fourfold greater among subjects with asthma than among control subjects (46/67 versus 12/81; odds ratio, 10.1; 95% confidence interval, 4.9 to 20.7). The population attributable risk for the presence of IgE Ab to one of the five allergens was greater than 50%. Among individuals older than 50 years of age, the prevalence of serum IgE Abs was not significantly increased among patients with acute airway obstruction. In the whole group, the prevalence of IgE Abs to different allergens demonstrated significant seasonal and socioeconomic differences, suggesting that the associated risk is related to exposure to those allergens. The results establish that, with acute attacks of asthma as a marker for adult asthma, the presence of serum IgE Abs to common inhalant allergens is a major risk factor.(ABSTRACT TRUNCATED AT 250 WORDS)