Ion translocation by the Escherichia coli NADH:ubiquinone oxidoreductase (complex I)

The energy-converting NADH:ubiquinone oxidoreductase, also known as respiratory complex I, couples the transfer of electrons from NADH to ubiquinone with the translocation of ions across the membrane. It was assumed that the complex exclusively works as a proton pump. Recently, it has been proposed that complex I from Klebsiella pneumoniae and Escherichia coli work as Na+ pumps. We have used an E. coli complex I preparation to determine the type of ion(s) translocated by means of enzyme activity, generation of a membrane potential and redox-induced Fourier-transform infrared spectroscopy. We did not find any indications for Na+ translocation by the E. coli complex I.

[Correlation of different types of emphysema in high-resolution computed tomography (HR-CT) with the ILO-classification of coal workers pneumoconiosis]

PURPOSE

The complaints of patients suffering from pneumoconiosis and the decrease in cardio-respiratory function tests are related to the major complications, emphysema or bronchitis, resp. to a lesser degree the complaints are directly influenced by the silicotic process itself. Up to now, no large study has analysed the correlation of different types and severity of emphysema with the ILO-classification of pneumoconiosis in miners.

MATERIAL AND METHODS

In 104 miners the severity of pneumoconiosis was classified by ILO. By HR-CT the type and severity of emphysema was analysed using a 4-point-scale. The correlation of emphysema with the ILO-classification was tested with Pearson-correlation.

RESULTS

The centrolobular emphysema was the dominant type with 59 %, but there was no dependence on the severity of pneumoconiosis. Only the paracicatricial emphysema had a significant correlation (p < 0.05) with the degree of large opacities. On the other hand, the paracicatricial emphysema was only detected in 32 %; under quantitative aspects it was seen to be less common than the centrolobular, the parapleural and the paraseptal emphysema (46 %). There was no significant correlation with the size and distribution of the small opacities and the different types of emphysema.

CONCLUSIONS

Only the large opacities had a significant correlation with the appearance of paracicatricial emphysema. The other types of emphysema, especially, the dominant centrolobular type had no obvious association with pneumoconiosis. The multifactoral genesis of emphysema has to be taken into account.

[Age-related social inequality in mortality]

Age-standardised mortality rates are often used in epidemiologic studies to describe the dimension of social inequalities in mortality. This, however, conceals any age-dependence of social inequality. In an ecologic study, all causes and cause-specific mortality of all citizens of Bochum, FRG, who died 1988-1990, were evaluated using 13.171 death certificates. Data was aggregated on census tract level. The social status of a census tract was determined using 6 variables from the census 1987 describing the socio-economic situation in each census tract. Census tracts were grouped into quintiles according to their social status. Age and sex-specific mortality rates as well as rate ratios, using the quintile with the highest social status as reference, were calculated. Results for men (n = 6.288) indicate that social inequality is age-dependent for total mortality. Social differentials are especially marked for the age groups 35-64 years. For age group < 35 years and > 84 years no social differentiation in mortality is visible. Similar patterns are found with mortality from cardiovascular diseases (ICD-9: 390-459) and cancer (ICD-9: 140-208). Mortality from diseases related to health behaviour such as lung cancer or diseases associated with high alcohol intake are characterised by social inequalities above average in the middle age groups. For total mortality in women (n = 6.883) large social differentials are found for age groups 25-34 years and 45-54 years. Efforts to reduce social inequality on community level should especially be aimed at adolescents and young adults living in underprivileged areas.

[Smoking among children and adolescents: a challenge for primary prevention]

The best way to prevent the deleterious health effects of cigarette smoking is helping children to refrain from starting the habit. As a part of a survey of the prevalence of asthma symptoms in children and adolescents, we investigated the smoking habits of grade seven and eight school children in Bochum, a city of approximately 400,000 people in northwestern Germany. A random sample of 2050 children (93%) answered a confidential questionnaire. Fifty-three percent of the children responded that they had ever smoked cigarettes and 26% indicated that they had smoked during the previous month. 10% of the teenagers smoked daily, and 5% smoked more than 10 cigarettes per day. The prevalence of active smoking during the previous month was more frequent among girls (28%) than among boys (23%), but slightly more boys (5%) than girls (4%) smoked more than 10 cigarettes per day. The prevalence of active smoking was increased among children living in families of lower socio-economic status or in households with smokers. The high prevalence of cigarette smoking among the school children in Bochum, Germany, emphasizes the need to develop and implement effective intervention programs for children and adolescents and to contribute to a social environment which is conductive to refraining from smoking.

[The 1990 Bochum cholesterol and blood screening program. Incidence and degree of treatment of cardiovascular risk factors]

STUDY

Over a four-week period, 1,454 inhabitants of the town of Bochum (567 men = 39%, 887 women = 61%) were screened for cardiovascular risk factors. The sample was recruited from voluntary participants, two-thirds of whom were aged between 50 and 69.

RESULTS

Age-adjusted mean total plasma cholesterol levels were 223 mg/dl for women, and 218 mg/dl for men. Age-adjusted mean systolic blood pressure were 136.7 mmHg for women, and 140.8 mmHg for men. The corresponding diastolic levels were 85.0 mmHg for women and 87.8 mmHg for men. The prevalence of hypercholesterolemia (greater than or equal to 250 mg/dl) was 32.8%, that of hypertension (greater than or equal to 160/95 mmHg) was 32.7%. Age- and sex-specific mean figures and prevalences were lower for total cholesterol and markedly higher for blood pressure as compared with representative German studies. Previously unknown hypertension (greater than or equal to 160 mmHg systolic and/or greater than or equal to 95 mmHg diastolic) was detected in 10%, and hypercholesterolemia (total cholesterol greater than or equal to 250 mgdl) in 16%. A reply postcard was received from the family doctors of only 11% of participants with elevated levels. This means that the follow-up rate remained far below the hoped-for level.

CONCLUSIONS

Population screening can be useful in promoting primary and secondary cardiovascular disease by alerting the population to classical risk factors and informing participants about their own personal situation. In order to motivate individuals with high risk factors to act upon this information, screening should be associated with follow-up.