Kontaktekzem auf Chromate und Alterungsschutzmittel (Gummihandschuhe!)

Ohne Zusammenfassung     

What becomes of pulmonary infarcts?

In 32 patients, 58 angiographically proven pulmonary infarcts were followed for 3 months or longer by serial chest radiography. Complete clearing was seen in 29 (50%) of the infarcts on chest radiography. In the other 29 infarcts that left residual findings, linear scars were identified in 14, pleural diaphragmatic adhesions in nine, and localized pleural thickening in six; in all cases the features were diminutive when compared with the original abnormality. Follow-up perfusion lung images at similar time intervals to the chest films were available for 44 infarcts. Seven of these showed complete resolution and the other 37 showed a residual but much smaller perfusion defect. None of the patients had known preexisting pulmonary disease. The frequency of permanent radiographic scarring seemed to be the same at all ages.     

Lead toxicity in the shipbreaking industry: the Ontario experience

Lead exposure occurs during ship demolition when the ship structure has been previously coated with lead-based paint. An investigation and follow-up of employee lead exposure at the 4 shipbreaking operations in Southern Ontario revealed widespread excessive lead exposure. Air sampling results for lead were above the Ontario standard at all locations. 34 of 113 workers (30%) had at least one blood lead above 3.4 mumol/L*; 50% of workers at one company had results above 2.5 mumol/L. At these blood levels, neurologic, renal and hematologic effects may develop. Institution of control measures (appropriate respirators and hygiene practices, worker education and training, prompt employee notification of blood lead levels) reduced employee lead exposure and lowered blood lead results. Continued vigilance and ongoing employee education and training are required to prevent lead toxicity in shipbreaking. *70 micrograms/100 ml = 3.4 mumol/L.     

Die Wirkung von Salzlösungen unterschiedlicher Ionenzusammensetzung auf die Schwimmaktivität der Cercarien von Schistosoma mansoni

Ohne Zusammenfassung     

Über das auftreten von verzweigungsreaktionen bei der copolymerisation von trioxan mit 1,3-dioxolan

In principle, branched macromolecules can be formed during the homopolymerization of trioxane. Because of the thermal instability of trioxane homopolymers, however, the formation of branched structures is particularly difficult to prove; the conditions are more favorable in the case of trioxane copolymers. On the basis of comparative tests with respect to spherulite size and by various degradation experiments carried out with trioxane copolymers, blockcopolymers, and terpolymers we found first experimental indications of the occurrence of branching reactions with oxymethylene and oxyethylene groups during polymerization. In a first stage there is a hydride transfer with formation of a new cationic center followed by a second stage in which a cleavage or branching reaction takes place. In the copolymerization of trioxane with 1,3-dioxolane cleavage predominates especially at higher polymerization temperatures, whereas in the blockcopolymerization of trioxane/l,3-dioxolane with polyglycol the hydride transfer at the polyoxyethylene chain preferably results in branching reactions.     

Modern treatment of the symptomatic os odontoideum

A new surgical procedure for treatment of congenital, symptomatic atlanto-axial instability (os odontoideum ) is described. Two metallic clamps, with an integrated inner spring for maintaining continuous pressure on a cortico-cancellous bone-graft implanted into the interlaminar space, are fixed posteriorly on the vertebral arches C1/2 next to the graft. Because of the initial solid segment-stability external fixation is unnecessary. Posterior interlaminar osteosynthesis prevents late neurological complications caused by a mobile os odontoideum .