Mercury in blood cells—Altered elemental profiles

The study was composed of 27 persons that displayed vague symptoms similar to those of the victims of Minamata and Iraq. Skew distributions of mercury were observed in individual erythrocytes and neutrophil granulocytes when measured by PIXE. Mercury could not be detected in the platelets. The erythrocytes also displayed lowered concentrations of magnesium and zinc, together with increased concentrations of calcium and strontium. The neutrophils displayed decreased concentrations of magnesium and zinc and increased concentrations of calcium, strontium, and iron. The presence of mercury and the altered elemental profiles in the erythrocytes and the neutrophil granulocytes are suggested as early signs of exposure.     

Cytochrome P-450 dependent ethanol oxidation. Kinetic isotope effects and absence of stereoselectivity

Deuterium isotope effects [D(V/K)] and stereoselectivity of ethanol oxidation in cytochrome P-450 containing systems and in the xanthine-xanthine oxidase system were compared with those of yeast alcohol dehydrogenase. The isotope effects were determined by using both a noncompetitive method, including incubation of unlabeled or [1,1-2H2]ethanol at various concentrations, and a competitive method, where 1:1 mixtures of [1-13C]- and [2H6]ethanol or [2,2,2-2H3]- and [1,1-2H2]ethanol were incubated and the acetaldehyde formed was analyzed by gas chromatography/mass spectrometry. The D(V/K) isotope effects of the cytochrome P-450 dependent ethanol oxidation were about 4 with liver microsomes from imidazole-, phenobarbital- or acetone-treated rabbits or with microsomes from acetone- or ethanol-treated rats. Similar isotope effects were reached with reconstituted membranes containing the rabbit ethanol-inducible cytochrome P-450 (LMeb), whereas control rat microsomes and membranes containing rabbit phenobarbital-inducible P-450 LM2 oxidized the alcohol with D(V/K) of about 2.8 and 1.8, respectively. Addition of FeIIIEDTA either to microsomes from phenobarbital-treated rabbits or to membranes containing P-450 LMeb significantly lowered the isotope effect, which approached that of the xanthine-xanthine oxidase system (1.4), whereas desferrioxamine had no significant effect. Incubations of all cytochrome P-450 containing systems or the xanthine-xanthine oxidase systems with (1R)- and (1S)-[1-2H]ethanol, revealed, taking the isotope effects into account, that 44-66% of the ethanol oxidized had lost the 1-pro-R hydrogen.(ABSTRACT TRUNCATED AT 250 WORDS)     

N-Deacetylation of 2-acetamido-2-deoxy-hexosecontaining oligosaccharides and polysaccharides by calcium in liquid ammonia

N-Deacetylation of 2-acetamido-2-deoxy-hexose residues is accomplished in liquid ammonia containing calcium. Oligosaccharides, lacto-N-fucopentaose II and lacto-N-difucohexaose I, containing 3,4-disubstitutedN-acetylhexosamine residues are quantitativelyN-deacetylated. When applied to polysaccharides, however, only partialN-deacetylation was achieved.Author for correspondence. AXRD     

Hedbergia, a new genus of Scrophulariaceae from Africa

Hedbergia is described as a new, monotypic genus in the Scrophulariaceae, subfamily Rhinanthoideae, tribe Rhinantheae. The species H. abyssinica is transferred from Bartsia. Hedbergia abyssinica is the most primitive taxon so far known in the subtribe Euphrasineae.     

Recovery of malondialdehyde in urine as a 2,4-dinitrophenylhydrazine derivative after exposure to chloroform or hydroquinone

Malondialdehyde (MDA) excretion in urine as an index for toxicological effects of chloroform and hydroquinone was evaluated. In a first series of experiments three groups of rats were used: non-pretreated rats (group I), starved rats (group II) and starved plus phenobarbital pretreated rats (group III). Chloroform (0.15 or 0.30 ml/kg, p.o.) was given as a single dose. The MDA excretion was related to the pretreatment, and in group III to liver damage. In a second series of experiments control rats were administered hydroquinone (100 or 200 mg/kg, p.o.), which induced a dose-related MDA excretion. These data indicate that the MDA assay was a selective and accurate marker for toxicological effects induced by the tested compounds.     

Epidermal ultrastructure of Anoplodium stichopi (Plathelminthes,Dalyellioida), a flatworm endosymbiotic in Stichopus tremulus (Holothurioida)

Summary The epidermal ultrastructure of Anoplodium stichopi Bock 1925 (Platyhelminthes, Dalyellioida, Umagillidae) was studied using transmission and scanning electron microscopy. The species lives in the perivisceral coelom of the aspidochirote holothurian Stichopus tremulus Gunnerus 1767. Two types of cells were observed in the epidermis of A. stichopi: ciliated cuboidal epithelial cells and nonciliated pear-shaped cells. The surface of the ciliated epidermal cells is folded into anastomosing ridges. Numerous coated vesicles are subjacent to the surface folds and mitochondria are abundant just below them. Observations indicate that A. stichopi takes up nutrients pinocytically from the coelomic fluid of the host. The ciliation of A. stichopi is sparse.     

The incorporation of selenium and alterations of macro- and trace element levels in individual blood cells following supplementation with sodium selenite and vitamin E

Significant alterations in the selenium content of erythrocytes, thrombocytes, and neutrophil granulocytes were observed following a daily supplementation of 200 μg Se + 100 mg vitamin E during a period of 2 months. The neutrophil granulocytes incorporated more selenium than the thrombocytes. The iron content of the thrombocytes decreased on selenium supplementation, while the opposite was noted for the neutrophil granulocytes. The glutathione peroxidase activity was not significantly changed during the period of observation.     

Ontogenetic development of the pineal organ,parapineal organ,and retina of the three-spined stickleback,Gasterosteus aculeatus L. (Teleostei)

The ontogenetic developments of the pineal organ, parapineal organ, and retina were studied by the use of light and electron microscopy in embryos and fry of the teleost, Gasterosteus aculeatus, from 60 to 168 h after fertilization. Sixty to 66 h after fertilization, the primordium of the pineal complex is discernible in the diencephalic roofplate; the parapineal anlage is located rostral to the pineal anlage. Photoreceptor cells endowed with outer segments are present in the embryonic pineal organ already after 72 h, whereas outer segments of retinal photoreceptors could not be demonstrated before 144 h (hatching occurs between 120-144 h). Furthermore, neuropil formations with synaptic specializations are present in the rostral part of the pineal organ 108 h after fertilization. At 72 h, the embryonic parapineal parenchyma is already differentiated into parapinealocytes, which give rise to the parapineal tract, and glia-resembling elements. Although parapinealocytes carry cilia (9 X 2 + 0), only a single outer segment of the photoreceptor type could be demonstrated in the parapineal organ of one adult stickleback. Photoreceptors present in the pineal organ of unhatched embryos are hardly involved in visual functions, but may already at this early developmental stage serve as photoneuroendocrine transducers.