Functional anatomy of the musculature of the trachea.

The smooth musculature of the human trachea was studied and compared with earlier observations in the rabbit. The results may be summarized as follows: 1. The annular m. constrictor tracheae, previously observed in the rabbit, has also been identified in the human trachea. 2. Longitudinal muscle fibers outside the constrictor musculature were observed in man. These fibers are rudimentary and appear to be of no functional importance. 3. From a functional point of view, it appears justified to regard the outer tracheal musculature largely as a constrictor musculature. 4. The main function of the outer musculature of the trachea and the elastic cartilaginous arches is to maintain the stability of the tracheal wall. 5. The variation of the lumen of the trachea is mainly controlled by the m. trachealis in the pars membranacea.     

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.     

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.     

DNA replication and H5 histone exchange during reactivation of chick erythrocyte nuclei in heterokaryons

Fusion of terminally differentiated chick erythrocytes (CE) with replicating quail myoblasts or established L6J1 rat myoblasts results in reactivation of DNA synthesis in the dormant CE nuclei and in suppression of DNA synthesis in the myoblast nuclei. The nuclei of primary quail myoblasts are more effectively inhibited than the nuclei of established rat myoblasts. Inhibition of DNA replication occurs not only by preventing G1 nuclei from entering S-phase but also by blocking nuclei in S-phase and by delaying nuclei in G2 from undergoing mitosis and starting a new DNA replication cycle. No inhibition of DNA synthesis could be observed when mouse erythrocytes, i.e., erythrocytes lacking nuclei, were fused with rat myoblasts to generate mouse-globin-containing L6J1 cybrids. — Reactivation of CE nuclei is associated with a loss of the tissuespecific H5 histone variant. Complete elimination of H5 histone, however, does not seem to be a necessary prerequisite for the initiation or completion of DNA replication in CE nuclei since H5 antigens are found on reactivated G1, S, and G2 nuclei.     

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.     

Degradation of heparin in mouse mastocytoma tissue

1. Heparin was prepared from mouse mastocytoma tissue by mild procedures, including extraction of mast-cell granules with 2m-potassium chloride, precipitation of the extracted polysaccharide with cetylpyridinium chloride from 0.8m-potassium chloride and finally digestion of the isolated material with testicular hyaluronidase. The resulting product (fraction GE(H)) represented approx. 40% of the total heparin content of the tissue. 2. Fraction GE(H) was fractionated by gel chromatography on Sepharose 4B into three subfractions, with average molecular weights ( M(w)) of approx. 60000-70000 (highly polydisperse material), 26000 and 9000 respectively. Treatment of each of the subfractions with alkali or with papain did not affect their behaviour on gel chromatography. Amino acid and neutral sugar analyses indicated that the two low-molecular-weight fractions consisted largely of single polysaccharide chains lacking the carbohydrate-protein linkage region. It was suggested that these heparin molecules had been degraded by an endopolysaccharidase. 3. Pulse labelling in vivo of mastocytoma heparin with [(35)S]sulphate showed initial labelling of large molecules followed by a progressive shift of radioactivity toward fractions of lower molecular weight. Further, heparin-depolymerizing activity was demonstrated by incubating (35)S-labelled heparin in vitro with a mastocytoma 10000g-supernatant fraction. Appreciable degradation of the polysaccharide occurred, as demonstrated by gel chromatography. In contrast, no depolymerization was observed on subjecting (14)C-labelled chondroitin sulphate to the same procedure.