Supported liquid membrane technique for selective sample workup of basic drugs in plasma prior to capillary zone electrophoresis.

The potential of using the supported liquid membrane (SLM) technique for pretreatment of plasma samples before analysis with capillary zone electrophoresis (CZE) has been investigated. A basic drug, bambuterol, was used as a model substance in a system, where either 6-undecanone or a mixture of di-n-hexyl ether (DHE) and tri-n-octyl phosphine oxide (TOPO) was used as membrane liquids. It was found that the electropherograms obtained after SLM enrichment of bambuterol in plasma samples were as clean as when aqueous samples containing the same substance were processed in the same way. The low ionic strength of the SLM treated blood plasma samples permitted subsequent sample stacking in the CZE step. The linearity of the detector signal for different concentrations of bambuterol in plasma was satisfactory from 50 to 1000 nmol/L with regression co-efficients of 0.997 using 6-undecanone as membrane liquid and 0.999 with the other liquid. In both systems, the confidence interval of the intercept included the origin. The detection limit was about 50 nmol/L. The long-term stability of the two membrane liquids proved adequate as a membrane lasted at least through the working day.

Liquid membrane work-up of blood plasma samples applied to gas chromatographic determination of aliphatic amines.

A technique for sample work-up and enrichment using a supported liquid membrane in an automated flow system, connected to a gas chromatograph, was used for the determination of aliphatic amines in human blood plasma. The amines studied were N,N-dimethylethylamine, triethylamine, N-methylmorpholine, cyclohexylamine and N,N-dimethylcyclohexylamine. An efficient clean-up of the complex plasma matrix was achieved, resulting in identical blank chromatograms for plasma samples and aqueous solutions. Different parameters influencing the efficiency and selectivity of the extraction procedure were experimentally studied and theoretically explained. The detection limit depends on the extraction flow-rate and the available sample volume. With 1 ml of sample and a flow-rate giving an extraction time of 16 min, the detection limit was ca. 5 ppb (5 micrograms/l); with 4 ml of sample and a lower flow-rate, sub-ppb detection limits could be reached in ca. 3 h. Linear calibration curves up to 500 ppb were obtained. Blood plasma samples from volunteers exposed to N,N-dimethylethylamine in air were analysed, and the results compared favourably with independent measurements by another method.

Controlled thermal degradation for the identification and quantification of amine N-oxides in urine.

Studies of amine N-oxides in urine are important for the evaluation of occupational exposure to amines. These thermolabile compounds are difficult to handle by either gas or liquid chromatography, so a device for controlled thermal degradation has therefore been developed. It consists of a short precolumn with shut-off valves at both ends and an aluminum block for heating, and it was connected to the injection port of a gas chromatograph. After injection of amine N-oxides onto the precolumn and thermal degradation, the degradation products were allowed to enter the analytical column. Trimethylamine N-oxide (TMAO) and triethylamine N-oxide (TEAO) were investigated. Their thermal degradation patterns could be used for identification and quantification in aqueous solutions and in urine. Linear calibration graphs based on degradation product peaks (trimethylamine and O,N,N-trimethylhydroxylamine from TMAO and diethylamine and triethylamine from TEAO) were obtained for concentrations up to 500 ppm. Detection limits in aqueous solutions were 0.2 ppm (ca. 1 ng) for TMAO and 1 ppm for TEAO and the precisions were 6% and 9%, respectively. In urine, similar values were obtained for TEAO. The detection limit for TEAO corresponds to the expected concentration in urine after an 8-h exposure to air containing 0.8 mg/m3 of triethylamine.

Breast cancer among women from Gothenburg with regard to age, mortality and coexisting benign breast disease or leiomyoma uteri.

The entire female population of Gothenburg, aged 20 years or above as of November, 1969 (n = 162,449), was studied for virtually all inpatient hospital admissions in 1970-1979 with breast cancer (n = 2,411). After the vital status as of December, 1984 had been traced, cases of fetal (n = 1,502) and of nonfatal (n = 909) breast cancer were separated. A search for coexisting benign breast disease and leiomyoma uteri yielded significant recordings of disease association exclusively with nonfatal breast cancer.

Mortality and fatality of cutaneous malignant melanoma in Sweden, 1982-1986.

Among almost all cases of death from cutaneous malignant melanoma in Sweden during the 5-year observation period of 1982-86 (n = 1406), 58.5% were male. For both sexes, considered together, 80.5% were aged greater than 49 yr at the time of death; 62.9% aged greater than 59 yr, and 36.7% aged greater than 69 yr. Disease fatality, assessed as the sex and age-specific mortality between 1982 and 1986 in proportion to the age and sex-specific incidence in 1977 and 1982, increased significantly (P less than 0.001) with age in both sexes, in terms of distributional heterogeneity. Likewise, in both sexes, disease fatality was higher (P less than 0.025) in the area of Sweden north of the N 60 degrees latitude line rather than south of it. As it is a crucial measure of treatment efficacy in cutaneous malignant melanoma, case fatality deserves more attention in future epidemiologic research than it has received to-date. In this context, a revision of the criteria for histopathological "malignancy" at initial treatment against empirical data on the outcome quoad vitam is warranted.

Kinetics of calcium binding to calbindin mutants.

The kinetics of calcium dissociation from wild-type bovine calbindin D9k (the smallest protein known with a pair of EF-hand calcium-binding sites) and five mutants with single amino-acid substitutions and/or deletions has been studied by stopped-flow fluorescence methods, using the calcium chelator Quin 2. The modifications are confined to the N-terminal half of the molecule, at or near the first calcium-binding site (I). Substitutions and deletions of amino acids in the calcium-binding loop of site I primarily affect the rate of Ca2+ dissociation from this site with only minor effects on the dynamic properties of the C-terminal calcium-binding site (II). This finding corroborates and extends previous kinetic results obtained from 43Ca-NMR studies on the same set of mutants. By contrast, removal of the hydrogen bond between Tyr-13 and Glu-35, an interaction linking the two alpha-helices flanking site I, through replacement of Tyr-13 with Phe, has no observable effect on the rate of Ca2+ dissociation from the protein. Comparison of this kinetic data with binding-constant data, previously obtained in our laboratories, shows that the decrease in Ca2+-affinity of site I, observed in most mutants, is predominantly due to an increased off-rate from this site. At low ionic strengths the second-order rate constants for Ca2+-binding to both Ca2+ sites of calbindin D9k are calculated to be of the order of 10(9) M-1 s-1 for all proteins studied. At higher ionic strengths (0.1 M KCl) the rates of Ca2+ dissociation from both sites are increased by a factor of three or more, suggesting a transition state which is ionic in nature.

High-dose estrogen-progestagen oral contraceptives: a risk factor for aneurysmal subarachnoid hemorrhage?

A 10-year follow-up (1970-79) of a defined general population (n = 159 200) of middle-aged (born in 1911-40), urban, native Swedes, revealed that the prevalence rate of subarachnoid hemorrhage was 2.8 times higher in females than in males. This was mainly due to an accumulation of non-hypertensive aneurysmal subarachnoid bleeds in women born in the period 1932-40. The cases were significantly (P less than 0.001) overrepresented among divorced women, with relative risks of 1.89, 0.98 and 0.63 for divorced women, married women and spinsters (never married), respectively. Since high-dose estrogen-progestagen oral contraceptives have largely been used by the younger members of this study cohort, it may be speculated whether the observed substantial excess prevalence rate of subarachnoid hemorrhage with saccular aneurysm, not reported previously, represents a cohort effect unexpected after the introduction of low-dose oral contraceptives.

Associations between brain infarction, diabetes and alcoholism: observations from the Gothenburg population cohort study.

The relationship of brain infarction to diabetes and alcoholism was studied in a 10-year follow-up of a defined general population (n = 159,200) of native, urban Swedes. Confounding bias due to high age and lower socioeconomic conditions was reduced with a new epidemiological technique which was used instead of conventional mathematical multivariate procedures. We observed 6-13-fold and 4-6-fold excess rates of subjects with brain infarction among diabetics (P less than 0.001) and alcoholics (P less than 0.001), respectively. In addition, diabetes and alcoholism were often found to be associated. The distribution of these diseases varied with the topography of the city and demography of the population. Hence, in future studies into the pathogenesis of brain infarction, study samples should be made homogeneous not only from a clinical, but also from an epidemiological point of view. We conclude that diabetes, alcoholism and both in combination, associate with brain infarction.

Diseases associated with psoriasis in a general population of 159,200 middle-aged, urban, native Swedes.

A defined general population of 159,200 male and female native Swedes born in the period of 1911-1940, from an urban catchment area of the then only general hospital, was followed over a decade (1970-1979) with regard to inpatient hospitalization for all kinds of diagnoses. Psoriasis cases (n = 372) are significantly (p less than 0.001) associated with a spectrum of diseases: male as well as female psoriatics seem to show excess rates of viral infections, alcoholism, hypertension, pneumonia, liver cirrhosis, urticaria, and rheumatoid arthritis. Psoriasis in males only seem to be associated with iritis and ankylosing spondylitis, whereas psoriasis in females only is associated with lung cancer, diabetes, obesity, myocardial infarction and asthma.

Marital state, alcohol consumption, and liability to myocardial infarction, stroke, diabetes mellitus, or hypertension in men from Gothenburg.

Data from the Swedish personal number system were used to examine rates of admissions to hospital, particularly with myocardial infarction, stroke, diabetes mellitus, or hypertension, in relation to marital state and histories of admission with alcoholism in 77843 men from Gothenburg born in 1911-40. The number of admissions to hospital with the four diseases varied with marital state and history of admission with alcoholism, but by considering each subset from the total group it was possible to show that among alcoholic men no material variation in the number of admissions was evident. By contrast, among the non-alcoholic men those who were married were particularly prone to myocardial infarction but less likely to be admitted with stroke or diabetes mellitus than the unmarried or divorced men. The data show the value of common personal and health statistical numbering systems in generating epidemiological information beyond that obtainable from aggregated data without a record linkage technique.

Diseases associated with multiple sclerosis and epilepsy. A population cohort study of 159,200 middle-aged, urban, native Swedes observed over 10 years (1970-79).

A defined general population of 159,200 male and female native Swedes born in the period 1911-1940 from an urban catchment area of the then only general hospital, was followed over a decade (1970-79) with regard to in-patient hospitalization for all kinds of diagnoses. As a part of this population cohort study, multiple sclerosis cases (n = 351) and epilepsy cases (n = 648) were studied for association with other diseases. Unexpectedly, a cluster of diseases encompassing tuberculosis, bronchial asthma, diabetes mellitus and myocardial infarction, among the diseases associated with multiple sclerosis, also forms a gradient; this suggests a quantitative rather than a qualitative multifactorial model of disease for the understanding of the pathogenesis of MS. In epilepsy, heterogeneity was suggested as being mainly linked to the presence or absence of co-existing alcoholism. Brain tumours in cases of epilepsy were found almost exclusively in the latter subset and prevailing among younger people independent of sex (with an almost 100-fold excess rate of that disease combination as expected by chance only).

Physical illness in severe depressives and psychiatric alcoholics in Gothenburg, Sweden.

The entire middle-aged male urban population of a Swedish city, as defined by a census in November 1969, was assessed for any mental hospital hospitalization during a 3-year period (1978-1980), as well as for any general hospital hospitalization during a 10-year period (1970-1979) within the catchment area. Inpatients of the mental hospital population belonging to the cohort and put in the categories 'Psychiatric alcoholic spectrum' and 'Severe depression' were studied for diagnoses of physical illness during any general hospital hospitalization. The psychiatric alcoholic spectrum was associated positively with infections, injuries, alcohol intoxication, pancreatitis, liver cirrhosis, arthritis/rheumatic diseases and duodenal peptic ulcer; and negatively with malignant neoplasms, myocardial infarction, gallstone disease and urolithiasis. Severe depression was associated positively with infections, myocardial infarction, asthma and alcohol intoxication. A nosologic taxonomy, aimed at explaining the epidemiological associations recorded, is suggested.