Prevalence of hepatitis B infection among hospital personnel in Addis Ababa (Ethiopia)

Hepatitis B serological markers (HBsAG, anti-HBc and anti-HBs) were determined in 432 (60%) hospital employees by the Hepanostika microenzyme linked immunoassay method.The overall prevalence rate was 9.02% for HBsAg, 46.25% for anti-HBs, 73.6% for anti-HBc and 76.38% for at least one marker positive. Marker positivity as well as HBsAg carrier rate is higher for males than for females. (82.0 Vs 69.9%; 11.4 Vs 6.75% respectively). The majority of the infections occur early in life, 75% being positive for at least one marker by age twenty. The distribution of markers is somewath different from previous observations with non-hospital personnel.Departments most exposed to blood and certain job categories seem to be an increased risk of acquiring the infection.We conclude that hospital exposure is associated with an additional risk of hepatitis B infection.     

Residual organochlorine pesticides in the fat of mutton birds of New Zealand

Summary The organochlorine insecticides pp-DDT, its metabolites pp-DDE and pp-DDD, -HCCH, HEOD and PCBs were identified in the fat of mutton birds of New Zealand. The mean levels for six adult birds were: total DDT 17.30 ppm (78% pp-DDE), pp-DDT 1.54 ppm, pp-DDE 13.50 ppm, pp-DDD 0,64 ppm, -HCCH 5.17 ppm, HEOD 0.93 ppm, PCBs 1.83 ppm. All the compounds found in the adult birds except -HCCH, were also present in a chick bird but in considerably smaller amounts.     

Belgian collaborative study of the in-vitro susceptibility of the Bacteroides fragilis group

The antimicrobial susceptibility of clinical isolates of the Bacteroides fragilis group obtained from nine large Belgian university and community hospitals was studied. Of the -lactam antibiotics tested, none were active against 100% of the isolates. Piperacillin was active against 93% of the strains at a breakpoint of 64 lag/ml. The percentage of isolates inhibited at 16 g/ml (and 32 g/ml) for the 7-alpha-methoxy antibiotics was: cefoxitin 84 [94]; latamoxef 87 [93]; and cefotetan 64 [79]. B. fragilis tended to be more susceptible to all -lactams than the other members of the group.Among the non -lactam antibiotics, the resistance rate for minocycline, doxycycline, clindamycin and erythromycin (at a breakpoint of 4 g/ml) were l%, 4%, 14% and 34%, respectively. Like the -lactams, clindamycin was less active against non B. fragilis species of the group.Chloramphenicol, metronidazole and tinidazole were still active against 100% of the isolates at their breakpoint values (8 lag/ml).     

Extended-spectrum β-lactamases fromKlebsiella pneumoniae strains isolated at an Italian hospital

Eighteen strains ofKlebsiella pneumoniae recently isolated from hospitalized patients were resistant or moderately resistant to oxyimino-cephalosporins (ceftazidime and/or cefotaxime), aztreonam, cefoxitin and all but one were susceptible to imipenem. Analysis of enzymes produced by these clinical isolates revealed a wide pattern of extended-spectrum -lactamases. All isolates produced one or more -lactamases that were characterized preliminarily by their isoelectric point. Strains isolated early were from patients in the Intensive Care Unit and produced an ES-lactamase with an apparent pI of 7.6, whereas the later isolates were from surgical and medical wards of the same hospital and produced ES-lactamases with apparent pI of 8.2 and 8.4, repectively. This suggests the emergence of SHV-5 and MIR-1 -lactamases in our hospital. Agarose gel electrophoresis of plasmid DNA revealed the presence of a similar plasmid of approximate size 60 Kb in all isolates.     

Effect of environmental toxicants on enzyme biosynthesis: A comparison of β-galaclosidase, α-glucosidase and tryptophanase

Except for -galactosidase, little is known about the effect of environmental toxicants on enzyme induction. The information could be potentially useful for the development of low-cost and rapid ecotoxicity assays. The effect of toxicants on thede novo biosynthesis of three inducible enzymes, -galactosidase and tryptophanase inE. coli and -glucosidase inB. subtilis was investigated. Biosynthesis of -glucosidase was the most sensitive to environmental toxicants, particularly pentachlorophenol and sodium dodecyl sulfate. The sensitivity ofB. subtilis to toxicants was further increased when Tween^® 80 was incorporated in the growth medium.     

Occupational exposure to hexachlorocyclohexane

Summary In a lindane (-hexachlorocyclohexane =-benzenehexachloride)-producing factory 57 workers were studied with regard to their blood levels of the three hexachlorocyclohexane isomers:-, -, and-HCH. The TLV-TWA (MAK value 1979) for-HCH of 0.5 mg/m³ was not exceeded at any of the workplaces where HCH is synthesized and purified to lindane. Additionally, in some of the workers samples of s.c. adipose tissue were taken for determination of HCH-isomer content. An external group of 20 clerks was examined in the same way for control purposes.In contrast to the control persons, none of whom had HCH-concentrations in serum above the respective detection limits, the values determined in serum of the exposed workers were in the following ranges:-HCH: 10–273 g/l,-HCH: 17–760 g/l, and-HCH: 5-188 g/l. Of special interest is the observation of a significant increase of-HCH-concentration in serum with the time of employment in lindane production, indicating a pronounced accumulation of this substance in the human organism. Concentrations of this isomer in s.c. adipose tissues were about 300-fold higher than in serum. A significant correlation between both parameters could be established.The results of this study show that adherence to the TLV-TWA of-HCH is not sufficient for control of HCH-exposure. Furthermore, biological monitoring of exposed workers is necessary taking into account the three more important isomers-, -, and-HCH.     

Alterations in rat liver microsomal enzymes following exposure to carbaryl and malathion in combination

Pesticides are a part of man's and animal's diet. The air we breathe and the water we drink also provide us with added measurable doses. Pesticides produce changes in -glucuronidase (-glu) content, which is highly concentrated in the liver. A study was conducted to examine the effect of carbaryl and malathion in combination on liver microsomal enzymes. In vitro studies which incubated rat serum, rat liver homogenate or purified -glu enzyme with 2 or 4 mM carbaryl and/or malathion had no effect on the -glu activity.Treatment with 50 mg/kg carbaryl daily for one week produced a significant 40% decrease in whole liver homogenate -glu activity. A single administration showed only a slight decrease through the 24-hr period examined. Rat liver subcellular fractionation studies revealed a significant decrease of 50% in microsomal -glu content one hr after a single administration of 50 mg/kg carbaryl. This decrease was correlated with a subsequent decrease in the microsomal -glu levels and was noted after daily treatment for one week with 50 mg/kg carbaryl.Incubation of 4 mM carbaryl with microsomal suspensions revealed a release of the microsomal -glu enzyme, whereas 4 mM malathion exerted an inhibition on the release of this enzyme. The combination of carbaryl and malathion (4/4 mM) produced an effect between that caused by either pesticide alone. This effect was not significantly different from the vehicle control until 30 min after the addition of the pesticide combination. To further exemplify an effect on the endoplasmic reticulum, it was observed that 25 mg/kg carbaryl, as well as 25/ 25 mg/kg carbaryl/malathion induced the UDP-glucuronyl transferase activity following daily treatment for seven days. These results revealed a decrease in microsomal -glu activity and calcium was correlated with their respective increases observed in the serum.     

Assessment of thyroid,testes, kidney and autonomic nervous system function in lead-exposed workers

Summary The objective of the study was to assess whether moderate occupational exposure to lead may be associated with early changes in potential target organs (thyroid, testes, kidney, autonomic nervous system). Workers exposed to lead in a lead acid battery factory (n = 98; mean blood lead 51 g/dl, range 40–75 g/dl) and 85 control workers were examined. None of the indicators of kidney function (in urine: retinol-binding protein, ₂-microglobulin, albumin,N-acetyl--d-glucosaminidase; in serum: creatinine, ₂-microglobulin), endocrine function (follicle-stimulating hormone, luteinizing hormone, thyroid-stimulating hormone, thyroxine, triiodothyronine) and autonomic nervous system (R-R interval variations on the electrocardiogram) were correlated with lead exposure (blood lead or duration of exposure) or showed significantly different mean values between the exposed group and controls. These results and an assessment of the published data suggest that compliance with the Directive of the Council of the European Communities on lead exposure (health surveillance in workers whose lead in blood exceeds 40 g/dl and removal from exposure when blood lead exceeds 70–80 g/dl) would prevent the occurrence of significant biological changes in the majority of lead-exposed workers.     

Association study of proposed candidate genes/regions in a population of Spanish asthmatics

A number of genes/regions have recently been reported to be linked to asthma or its related phenotypes (i.e. atopy and bronchial hyperresponsiveness), by genetic linkage and allele-sharing methods. We have performed a case–control study comparing the allelic distribution of nine microsatellite markers and two genetic variants in a group of patients attended at emergency room departments because of an acute attack of asthma with respect to an external healthy population of controls. A total of 146 asthmatic subjects and 50 population controls from Barcelona, Spain, were genotyped for nine microsatellite markers from some asthma/atopy candidate genes/regions: the -subunit of the high-affinity IgE receptor (FcRI-) located on chromosome 11; the 5q31–32 candidate region; the T-cell receptor genes, TCR- on chromosome 14 and TCR- on chromosome 7. Two genetic variants of the -subunit of the high-affinity IgE receptor (FcRI-) gene were also analyzed. None of the asthmatic or control individuals carried the Ile181Leu variant. There were no significant differences between asthmatic and control subjects neither for the polymorphic markers nor for the other variant of the -subunit of the high-affinity IgE receptor (FcRI-) gene. No association could be observed in this sample of Spanish asthmatics with the genes/regions studied.     

Effects of an Elementary School Intervention on Students' “Connectedness” to School and Social Adjustment During Middle School

This research examined the effects at follow-up during middle school of a comprehensive elementary-school intervention program, the Child Development Project, designed to reduce risk and promote resilience among youth. Parental consent to participate in the middle school study was obtained for 1,246 students from six program and six matched comparison elementary schools. Three of the program elementary schools were in the high implementation group, and three were in the low implementation group during the elementary school study. Findings indicated that, studywide, 40% of the outcome variables examined during middle school showed differences favoring program students, and there were no statistically reliable differences favoring comparison students. Among the high implementation group, 65% of the outcome variables showed differences favoring program students. Overall, program students were more engaged in and committed to school, were more prosocial and engaged in fewer problem behaviors than comparison students during middle school. Program students who experienced high implementation during elementary school also had higher academic performance, and associated with peers who were more prosocial and less antisocial than their matched comparison students during middle school. Implications of these findings for prevention programming are discussed.     

Decreased excretion of thioethers in urine of smokers after the use of β-carotene

Summary Epidemiologic studies have demonstrated an inverse relation between vitamin A intake and lung cancer rate. There is strong evidence that the provitamin A, -carotene, plays a more important role in the protective effect than vitamin A itself. The anticarcinogenic properties of -carotene have so far been attributed to its scavenger properties in deactivating or trapping reactive chemical species such as singlet oxygen and certain organic free radicals. Smoking results in increased excretion of detoxification products of electrophilic agents (mercapturic acids) in urine. Since reactive electrophilic intermediates are involved in carcinogenesis, we performed a double-blind, placebo-controlled intervention trial to investigate whether the intake of -carotene by smokers would affect urinary thioether excretion. Before the intervention the -carotene group (n = 62) and the placebo group (n = 61) had similar thioether excretion levels in urine (4.2 vs 4.3mmolSH/molcreatinine). During the intervention (20 mg -carotene daily for 14 weeks) the placebo group showed a 12% increase, whereas the -carotene group showed a 5% decrease (P=0.004). After the intervention the -carotene group had a 15% lower thioether excretion level than the placebo group (4.1 vs 4.7 mmol SH/mol creatinine; P=0.0017). Our study shows that urinary thioether excretion varies considerably over time, and that smokers have a decreased excretion of thioethers in urine after the use of -carotene. This latter observation suggests a role of -carotene in the detoxification of tobacco smoke constituents. Our observations warrant further studies on the involvement of -carotene in the generation and detoxification of electrophilic intermediates.     

Molecular epidemiology of nasopharyngeal corynebacteria in healthy adults from an area where diphtheria vaccination has been extensively practiced

In addition to conventional biochemical tests, a DNA probe specific for Corynebacterium diphtheriae was used to characterize 53 cystinase-positive and urease-negative corynebacteria strains isolated from pharyngeal and nasal swabs obtained from 515 healthy adults living in an urban area of central Italy. No Corynebacterium diphtheriae strain was found. Six atypical strains were isolated, which could not be classified in any of the species so far defined in the Corynebacterium genus. These strains appeared to be biochemically close to Corynebacterium pseudodiphtheriticum and genetically close to Corynebacterium diphtheriae, since their DNAs strongly hybridized, under relatively low stringency conditions, with a Corynebacterium diphtheriae-specific probe and since insertion sequences which are usually found in Corynebacterium diphtheriae genomes were also found to be present in their genomes. No one of these six strains was either toxigenic or susceptible to lysogenization by -corynephage carrying the tox gene. Therefore, they do not seem to have any epidemiological relevance as possible hosts for -phages.Corresponding author.     

Ultraviolet and volatility loss of herbicides

Herbicide 2,4-D formulated as a urea-type polymer was readily destroyed by long-wave uv (356-nm) irradiation, whereas conventional 2,4-D was more resistant. The opposite relationship was noted for polymeric and conventional formulations of dicamba. Polymerized 2,4-D was more resistant to thermal degradation (60°C) than non-polymerized formulations. Ultraviolet degradation of polymerized 2,4-D was eliminated by the incorporation of RYLEX-H and UVINUL D-50, industrial uv absorbers. Exposure of polymeric dicamba to 60°C heat, followed by trapping of the volatile component, indicated that 21 percent was lost by thermal degradation and 46.6 percent by volatilization. Comparable values for non-polymerized dicamba were 37.9 and 60.1 percent.     

Significance of urinary metallothionein in workers exposed to cadmium

Summary Cadmium in blood (Cd-B) and in urine (Cd-U) and metallothionein (Mt-U) and ₂-microglobulin in urine ( ₂m-U) were measured in 94 male Cd workers. The results were examined according to the workers' current exposure to cadmium (group C, n=73, workers currently exposed to Cd; group R, n=21, Cd workers removed from exposure or retired) and according to their renal status (group N, n=66, normal ₂m-U; group 1, n=28, ₂m-U>200 g/g creatinine). The interrelationships between Mt-U, Cd-U, Cd-B and years of cadmium exposure were examined in the various subgroups. The study of the correlations between these variables demonstrates that Mt-U is directly correlated with Cd-U but not with Cd-B or years of Cd exposure. The association between Cd-U and Mt-U is independent of the status of renal function and the intensity of current exposure to cadmium. Under moderate chronic exposure to cadmium, the fraction of Cd-U which is directly influenced by recent exposure (Cd-B) is small in comparison with that influenced by the cadmium body burden.     

Health behaviours and socio-economic status in Ontario, Canada

Data from the 1990 Ontario Health Survey were used to investigate the association of socio-economic status with the likelihood of meeting current recommendations for four health behaviours (smoking, fat intake, alcohol consumption, and physical activity level) in adults living in Ontario (Canada). Health behaviours were categorised as unhealthy if they did not meet current recommendations in Ontario (smoking, fat intake < 30% of dietary energy, alcohol intake < 14 units per week, low level of leisure-time physical activity). Two summary variables based on the number ofÔ unhealthyÕ behaviours were also examined: the crude number of unhealthy behaviours reported and the likelihood of reporting 3 or 4 unhealthy behaviours. Four measures of socio-economic status were used: educational achievement, household income status, source of household income, and occupational prestige. Multiple logistic and linear regression analyses were performed to explore the association of each unhealthy behaviour and of the summary variables with socio-economic status indicators (taken independently or simultaneously), controlling for demographic characteristics. Except for the positive relationship between income status and high alcohol intake, measures of unhealthy behaviours were inversely associated with the socio-economic indices, suggesting that individuals in lower socio-economic groups are at an increased risk for health problems.     

Temporal Trends of Organochlorine Pesticides in Prawn (<Emphasis Type="Italic">Macrobrachium nipponense</Emphasis>) from Lake Kasumigaura,Japan, During 1978–2000

Temporal trends of organochlorine pesticides such as -hexachlorocyclohexane (-HCH), hexachlorobenzene (HCB), and 1,1-dichloro-2,2-bis(p-chlorophenyl)-ethylene (p,p-DDE), were determined in freshwater prawn (Macrobrachium nipponense) collected from Lake Kasumigaura in 1978 to 2000. The organochlorine pesticides elucidated a 72.4% decrease in -HCH, from 42 (1978) to 11.6 ng/g fat (2000); an 89.6% decrease in HCB, from 1.64 (1978) to 0.17 ng/g fat (2000); and an 87.3% decrease in p,p-DDE, from 97.5 (1978) to 12.4 ng/g fat (1992). After organochlorine pesticide prohibition in 1971, the declining trend of -HCH, HCB, and p,p-DDE concentrations persisting in the prawns could be approximated by exponential equations.     

Effect of β-cyclodextrin on mucochloric acid and 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone

Cyclodextrins form inclusion complexes with a wide range of guest molecules which wholly, or in part, fit into their hydrophobic cavity. Since no covalent bonds are formed in this complexation, the guests can subsequently be eluted. The possibility of such complexation was envisioned as a means of removing chlorinated furanones from drinking water. Using a combination of infrared and ultraviolet techniques, evidence is presented for inclusion complex formation between mucochloric acid and -cyclodextrin in acidic aqueous solutions. Ultraviolet evidence supports the conclusion that under these acidic conditions, mucochloric acid exists in its cyclic form. Solid samples of the mucochloric acid--cyclodextrin complex could be isolated by recrystallization of a 11 mole ratio of the above compounds from water at pH 2. Solid sample infrared (potassium bromide or Nujol) showed a carbonyl shift of 20 cm^–1 when mucochloric acid was compared to the mucochloric acid--cyclodextrin complex. No such shift was found upon simply grinding together the above components. Thus the carbonyl shift is ascribed to inclusion complexation of mucochloric acid into the -cyclodextrin cavity.Melting point and thin-layer Chromatographic analyses also yielded supporting evidence for the formation of solid mucochloric acid--cyclodextrin complexes. Pilot studies with 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX), suggest a similar -cyclodextrin-complex formation in acidic solutions.     

Disposition of β-hexachlorocyclohexane,p,p′-DDT,and trans-chlordane administered subcutaneously to monkeys (Macaca fascicularis)

To evaluate skin lipid analysis for the accumulation level of environmental pollutants, the correlations between organochlorine pesticide residues in adipose tissue, blood, and skin lipids of monkeys were studied. The mixture of -hexachlorocyclohexane (-HCH), p,p-DDT, and trans-chlordane was subcutaneously given to monkeys once weekly for 5 weeks at dose levels of 1 and 10 mg/kg. The chemicals distributed in adipose tissue, blood, and skin lipids were determined six times after the last dosing at intervals of 4 to 9 weeks.Oxychlordane and p,p-DDE were detected in all tissues together with the administered chemicals. In blood and adipose tissue, trans-chlordane decreased rapidly and oxychlordane and p,p-DDE increased gradually and then remained at constant levels. -HCH and p,p-DDT in adipose tissue increased until the 12th week and then decreased in all animals. The correlation coefficients between blood and adipose tissue regardless of dose level and collection time for each chemical ranged from 0.83 to 0.94. Correlation coefficients between skin lipids and adipose tissue varied with the chemical, namely, 0.31, 0.72, 0.81, 0.81, and 0.83 for p,p-DDE, tras-chlordane, p,p-DDT, -HCH, and oxychlordane, respectively. The results indicated that skin lipid analysis may be useful for the evaluation of specific pollutants in the body burden.     

Diversity of β-lactamases among Klebsiella pneumoniae strains isolated in a university hospital in Greece

Among 48 clinical strains of Klebsiella pneumoniae isolated in a university hospital in Northern Greece, 29 (60.4%) exhibited resistance to third generation cephalosporins (3GC) and aztreonam. Thirty-two (66.7%) of the isolates were found resistant to the combination of ampicillin/sulbactam and six (12.5%) exhibited resistance to all the above antibiotics plus cefoxitin. Resistance to 3GC was related mostly with the presence of a -lactamase exhibiting pI 8.2 and substrate profile of an SHV-5 type enzyme and rarely (in two of the cefoxitin resistant strains) with the presence of plasmid-mediated class C cephalosporinases. Resistance to the ampicillin/sulbactam combination was associated with the presence of a -lactamase with pI 5.4, presumably representing a TEM-1 -lactamase. These findings record a diversity of -lactamases and explain, at least partly, the various -lactam resistance patterns observed in our K. pneumoniae sample.     

Einfluß des jahreszeitlichen Wechsels der Luftverunreinigung und der Wetterfaktoren auf die HÄufigkeit chronisch unspezifischer Atemwegserkrankungen

Zusammenfassung An 1292 unbeeinflut ausgewÄhlten MÄnnern und 843 Frauen wurden im Duisburger Stadtgebiet in der Zeit von Februar 1965 bis Juni 1966 der Einflu der atmosphÄrischen SO₂- und Feinstaubkonzentration sowie der Temperatur und Feuchtigkeitsbedingungen auf die HÄufigkeit unspezifischer Atemwegserkrankungen untersucht. Es zeigte sich sowohl bei MÄnnern als auch bei den Frauen im Monat Oktober bis Januar–Februar 1965/66 eine überdurchschnittliche HÄufung von Husten, Auswurf, Atemnot bei Anstrengungen und katarrhalischen AuskultationsphÄnomenen. Die jahreszeitlichen Unterschiede lieen sich sowohl bei MÄnnern als auch bei Frauen feststellen. Die Monate mit erhöhter Frequenz an subjektiven Bronchitissymptomen waren gekennzeichnet von einer überdurchschnittlichen Luftfeuchtigkeit sowie einer erhöhten Feinstaub- und SO₂-Konzentration bei niedrig liegender Auentemperatur.Die Gegenüberstellung objektiver Mewerte, wie des Sauerstoffdruckes, des intrabronchialen Strömungswiderstandes und des Anteils erhöhter BronchialwiderstÄnde, lie jedoch keinen Hinweis dafür erkennen, da mit der HÄufung von Atemnot und ganztÄgigem Husten eine Vermehrung obstruierender Bronchialerkrankungen oder andere Funktionsstörungen in der Lunge verbunden sind. Ein gleicher Befund ergab sich aus der Einzelanalyse mit Hilfe einer multiplen Regression. Offensichtlich ging von den in den Jahren 1965/66 in Duisburg auftretenden akuten Änderungen der SO₂- und Feinstaubkonzentrationen kein bronchoconstrictorischer oder die GasaustauschverhÄltnisse in der Lunge beeintrÄchtigender Einflu aus. Ebenso wie bei der beruflichen Staubbelastung gibt es vorlÄufig keinen Anhalt dafür, da die akute Reizung der oberen Luftwege durch atmosphÄrische und klimatische Faktoren, die zu einem vermehrten Auftreten von Husten, Auswurf und Atemnot führen, in die klassisch chronisch obstruktive Emphysembronchitis übergeht. Bei der Beurteilung der Studie mu jedoch berücksichtigt werden, da zum Zeitraum der Untersuchung im Duisburger Stadtgebiet keine extremen Verschmutzungsbedingungen geherrscht haben, wie sie für Smogperioden üblich sind.

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Influence of the seasonal changes of air pollution and of weather-factors on the incidence of chronic non specific respiratory diseasesVI. Communication

Summary In the period of February 1965 till June 1966 the influence of atmospheric SO₂ and dust concentrations as well as of temperature and humidity conditions on the frequency of non-specific airway diseases has been investigated on 1,292 randomly selected men and 843 women. In men as well as in women the incidence of cough, expectoration and dyspnoe at efforts in the months of October till January–February 1965/66 showed to be above the general average. The seasonal differences were to be found in men as well as in women. Characteristic of these months with increased frequency of subjective symptoms of bronchitis were an air humidity above the average as well as increased dust and SO₂ concentrations at low outside-air temperatures.The comparison of objective measuring values, for example, oxygen pressure, intrabronchial flow resistance and the proportion of increased bronchial resistance did not let recognize any indication to assume that, with the increase of dyspnoe and cough all the day, a multiplication of obstructive bronchial diseases or other functional lung disturbances must be associated. The same findings resulted from single analysis by means of a multiple regression. Evidently, there did not happen any bronchoconstrictive influence from the acute changes of the SO₂ and dust occurring in Duisburg in the years 1965/66, nor were the gas exchange conditions within the lungs affected. Just as in case of occupational dust-burdening, there is, up to now, no evidence that the acute irritation of the upper airways by atmospheric or climate factors, leading to an increased incidence of cough, expectoration and dyspnoe, graduates into the chronic obstructive bronchitis. The interpretation of the results of this study has, however to take into consideration that at the time of the investigation, no extreme air pollution conditions were present in the town district of Duisburg as they are common for periods of smog.