PM10 elemental composition and acute respiratory health effects in European children (PEACE project). Pollution Effects on Asthmatic Children in Europe

The ability of particles with a 50% cut-off aerodynamic diameter of 10 microm (PM10) to cause respiratory health effects possibly depends on their composition. This study evaluated whether the soluble elemental concentrations in PM10 were related to acute respiratory health effects. The Pollution Effects on Asthmatic Children in Europe (PEACE) study is a multicentre study of the acute effects of PM10 and other air pollution components on the respiratory health of children with chronic respiratory symptoms in urban and suburban panels. Children, 1208, divided among 17 panels were followed for > or =2 months. Exposure to air pollution was monitored on a daily basis. Health status was monitored by twice daily peak expiratory flow (PEF) measurements and a symptom diary. Median concentrations of iron ranged 105-1,110 ng x m(-3) in the urban and 32-517 ng x m(-3) in the suburban locations. The daily concentrations of most elements were not associated with daily variation in PEF, prevalence of respiratory symptoms or bronchodilator use. Silicon and iron concentrations tended to be negatively associated with PEF, and positively associated with the prevalence of phlegm. In two pollutant models, PM10 effect-estimates on phlegm prevalence were reduced and lost significance, whereas the effect-estimates of iron or silicon remained essentially unchanged. The effects of silicon and iron could not be separated. In conclusion, this study provides only weak support for the hypothesis that daily fluctuations in soluble elemental concentrations in ambient particulate matter are responsible for acute health effects.

Bifunctional fusion between nerve growth factor and a transferrin receptor antibody

The cDNAs encoding the variable regions of the heavy and light chains of a murine antibody specific for the human TfR were cloned and a human chimera (gamma1, kappa) was produced. A gene fusion was created by joining the 3' end of the coding region of the human nerve growth factor (NGF) precursor to the 5' end of the heavy chain variable region of the chimeric antibody. When expressed with the unmodified light chain in mammalian cells, the protein fusion is properly processed, assembled, and secreted. Subsequent purification and characterization established the uncompromised bifunctional activities of the protein, relative to the unmodified components, as demonstrated by its ability to both bind to the human TfR and induce neurite outgrowth in primary sympathetic or spinal ganglia and in trkA-transfected pheochromocytoma cells. The ability to generate biologically active NGF fused to a TfR targeting antibody, which was previously shown to cross the blood-brain barrier, may offer a novel way to deliver NGF and other neurotrophic factors to the central nervous system.

[Ginkgo extract EGb 761 (tenobin)/HAES versus naftidrofuryl (Dusodril)/HAES. A randomized study of therapy of sudden deafness]

80 patients with idiopathic sudden hearing loss existing no longer than 10 days were included in a randomised reference-controlled study. The therapeutic value of Ginkgo EGb 761 (Tebonin) + HAES was compared to that of Naftidrofuryl (Dusodril)+HAES. The main mechanisms of action of EGb 761 are a vasoregulating activity (increased blood flow), the platelet activating factor antagonism and a prevention of membrane damage caused by free radicals. Naftidrofuryl has antiserotonergic and therefore vasodilatory properties. The statistical analysis of the audiometric data was performed in measuring the relative hearing gain as described by Eibach 1979. After one week of observation, 40% of the patients in each group showed a complete remission of hearing loss. This was also observed by other authors who had compared other drugs. Therefore, in these cases, it is most likely that spontaneous recovery is the most important factor. After two and three weeks of observation, measuring the relative hearing gain, there was a significant borderline benefit of EGb 761 (p = 0.06) without any side effects. Some patients of the reference group developed side effects such as orthostatic dysregulation or headache or sleep disturbances. Minimising side effects should be one of the most important goals in therapy of sudden hearing loss until the efficiency of infusion therapy is proved.

Exposure to environmental tobacco smoke in the household and urinary cotinine excretion, heavy metals retention, and lung function

The relationship between urinary levels of cotinine (U-cotinine) and arsenic (U-As), blood levels of cadmium (B-Cd), blood levels of lead (B-Pb), lung function, and questionnaire data on smoking habits were studied in 107 parents and their 46 children (7-10 y of age). There was a statistically significant relationship between the reported amount of tobacco smoked and U-cotinine levels. Nonsmokers who were married to persons who smoked had three times higher U-cotinine levels than nonsmokers whose spouses did not smoke. There was a significant association between the number of parents who smoked in the family and the U-cotinine levels of children. If only one parent smoked, maternal smoking was of greater importance than paternal smoking. There was also an association between U-cotinine and B-Cd. A study of lung function in the children revealed that vital capacity and functional residual capacity (corrected for sex, age, and height) increased as the number of parents who smoked increased. Therefore, the present study showed that (1) U-cotinine was a useful index of active smoking and environmental tobacco smoke exposure in adults and children, (2) U-cotinine was associated with the blood concentration of cadmium, and (3) environmental tobacco smoke exposure was associated with changes in lung function of children.

Status of mercury and selenium in dental personnel: impact of amalgam work and own fillings

Urinary mercury (U-Hg) and plasma mercury (P-Hg) levels were higher in 244 dental personnel than in 81 matched referents (U-Hg: 1.8 and 1.1 mumol/mol creatinine, respectively; p less than .001; P-Hg: 6.7 and 6.2 nmol/l, respectively; p = .03). The amalgam in the mouth influenced mercury levels in whole blood (B-Hg), plasma, and urine. The association was nonlinear: the more amalgam, the larger the relative increase in mercury levels. The number of amalgam surfaces accounted for more of the variance in blood and urine mercury levels than did the number of fillings (e.g., U-Hg: 44% and 36%, respectively). The estimated increases in mercury level with rising amalgam load were 3.0%, 2.0%, and 0.8% per filled surface for U-Hg, P-Hg, and B-Hg, respectively (p less than .0001 in all cases). The impact of occupational exposure on U-Hg in the dental personnel corresponded to approximately 19 amalgam surfaces. Ceramo metallic restorations were associated with higher (31%) U-Hg.

Arginyl-tRNA synthetase from baker's yeast. Purification and some properties

Arginyl-tRNA synthetase from baker's yeast (Saccharomyces cerevisiae, strain 836) was obtained pure by a large-scale preparative method, which involves four chromatographic columns and one preparative polyacrylamide gel electrophoretic step. The enzyme has a high specific activity (9000 U/mg) and consists of a single polypeptide chain of molecular weight approximately 73000 as determined by polyacrylamide gel electrophoresis in the presence of sodium dodecylsulphate. Amino acid analysis of the enzyme permitted calculation of the absorption coefficient of arginyl-tRNA synthetase (A(1 mg/ml 280 nm)=1.26). Concerning kinetic parameters of the enzyme we found the following Km values: 0.28 muM, 300 muM, 1.5 muM for tRNA(Arg III), ATP and arginine in the aminoacylation reaction, and 1400 muM, 2.5 muM, and 50 muM for ATP, arginine and PP(i) in the ATP-PP(i) exchange reaction. Arginyl-tRNA synthetase required tRNA(Arg III) to catalyse the ATP-PP(i) exchange reaction.

Blood cell gamma-aminolevulinic acid dehydratase activity in humans exposed to methylmercury

The gamma-aminolevulinic acid dehydratase (ALA-D) activity in blood cells was studied in 15 subjects exposed to methylmercury through consumption of contaminated fish and 19 "unexposed" subjects with a similar sex and age distribution. The exposed subjects had a mean mercury level of 120 (range 15-370) ng/g blood cells while the controls had 9 (range 4-15) ng/g. Both groups had the same mean level of lead in whole blood (10+/-1 mug/100 ml). ALA-D activity decreased statistically significantly as both mercury and lead levels in the blood cells increased.