Hypochlorite reacts with an organic hydroperoxide forming free radicals, but not singlet oxygen, and thus initiates lipid peroxidation

The mechanism of the reaction of hypochlorite with t-butyl hydroperoxide as a model organic hydroperoxide was studied. The reaction produces chemiluminescence with rate constant 13 +/- 2 mM-1.sec-1. The chemiluminescence of this reaction was compared with that of the hypochlorite reaction with H2O2 where singlet oxygen (1O2) is formed. In the hypochlorite reaction with H2O2, the effect of hypochlorite concentration on the integrated chemiluminescence intensity is quadratic: a red filter with transmission > 600 nm did not significantly decrease the chemiluminescence intensity: substitution of D2O for H2O increased the luminescence intensity 10-fold; infrared monomol emission was observed at 1270 nm. These results confirm the formation of 1O2 during the hypochlorite reaction with H2O2. However, when t-butyl hydroperoxide was used instead of H2O2, the concentration effect significantly differed from quadratic, and the red filter decreased the luminescence intensity by approximately 99%; D2O slightly decreased the luminescence intensity. Finally, addition of t-butyl hydroperoxide to hypochlorite was not associated with monomol emission of 1O2 in the infrared region. The data exclude the possibility of singlet oxygen formation in the hypochlorite reaction with the organic hydroperoxide. According to 1H-NMR spectroscopy, di-t-butyl peroxide is the main product of the hypochlorite reaction with t-butyl hydroperoxide; its production can be explained by radical formation, i.e., by generation of t-butyloxy radical. t-Butyl hydroperoxide and cumene hydroperoxide promoted hypochlorite-induced lipid peroxidation of phospholipid liposomes. The free radical scavenger butylated hydroxytoluene completely inhibited this effect. The data suggest that organic hydroperoxides, always present in certain amounts in vivo, may be the intermediates that interact with hypochlorite-forming free radicals which are initiators of lipid peroxidation.     

Preparation and structure of the system (Na1−xLax) (Nb1−(2x_3)Mg2x_3)O3 with x = 0.51, 0.50, 0.435 and 0.4275

Abstracts are not published in this journal This revised version was published online in November 2006 with corrections to the Cover Date.     

Role of chlamydia in chronic renal and urogenital diseases in man]

Specimens of the joint surfaces of the tibia from patients with OA and RA were exposed were examined for bone mineralization, bone formation, osteoid tissue and bone resorption. Judging from the appearance of the osteoblasts in OA the sclerotic changes are mainly focal with relatively little osteogenesis. No osteoclasia was seen in the sclerotic areas. Breakdown of the mineralized cartilage is followed by the development of cysts with highly cellular connective tissue with high osteoblastic activity and osteoclasia. Osteoid tissue is relatively sparse. The changes in RA are more diffuse with a more active osteoblastic activity and widespread zones of osteoid tissue as well as resorption by osteoclasts. It appears as if the increased uptake of 85Sr in OA is more dependent on the occurrence of relatively inert osteosclerosis than on a rapid turnover of the bone tissue.     

Sample collection guidelines for trace elements in blood and urine. IUPAC Commission of Toxicology

This paper presents an organized system for element-specific sample collection and handling of human blood (whole blood, serum or plasma, packed cells or erythrocytes) and urine also indicating a proper definition of the subject and sample. Harmonized procedures for collection, preparation, analysis and quality control are suggested. The aim is to assist scientists worldwide to produce comparable data which will be useful on a regional, national and international scale. The guidelines are directed to the elements aluminium, arsenic, cadmium, chromium, cobalt, copper, lead, lithium, manganese, mercury, nickel, selenium and zinc. These include the most important elements measured for their occupational or clinical significance, and serve as examples of principles that will guide development of methods for other elements in the future.