Inhibition of chloride permeability and sodium transport in frog skin by mercusal and ethacrynic acid

Potential difference across the frog skin is increased 1-2 min after addition of 0.063-1.0 mg/ml ethacrynic acid or 0.2-1.0 mg/ml mercusal to outside Ringer solution. Within this time the short-circuit current remains unchanged or increased. Potential difference and short-circuit current are diminished after the addition of ethacrynic acid or mercusal to inside solution. This effect is similar to that of ouabain. These findings suggest that ethacrynic acid and mercusal inhibit chloride channel in the apical cell membrane, and inhibit sodium transport in the basolateral membrane.     

Further characterization of refractoriness in Aedes aegypti (L.) to infection by Dirofilaria immitis (Leidy)

Factors which control the expression of the refractory or susceptible condition to infection with Dirofilaria immitis in the mosquito. Aedes aegypti, were investigated using three protocols. (1) Microfilariae and prelarvae were injected into the hemocoel of susceptible A. aegypti. Some microfilariae and prelarvae developed to the L1 larval stage but they failed to complete development to the infective stage. (2) Enema of microfilariae and prelarvae from infected susceptible and refractory donor females were given into the midgut of uninfected susceptible and refractory recipient females. The results indicate that the conditions which inhibit the initiation of development are present in the Malpighian tubules and not in the midgut of the refractory mosquitoes. (3) Transplants of infected Malpighian tubules from susceptible and refractory donor females were made into the abdominal hemocoel of uninfected susceptible and refractory recipient females. The results showed that the refractory condition depends on the genetic makeup of the donor, not the recipient, mosquito. The above results taken as a whole indicate that the factors which control refractoriness are not present in the midgut but are present in the Malpighian tubule cells of refractory A. aegypti.     

Changes in the skin microvessel permeability following destruction of the mamillary-tegmental tract in normal and capsaicin-treated rats

An increase in vascular permeability as measured by the Evans Blue dye leakage into forepaws, was observed 1 hour following the destruction of mamillo-tegmental tracts in rats. Ten days after capsaicin pre-treatment the destruction did not induce any changes of the microvascular permeability in the skin forepaws. The findings suggest that the descending projections of hypothalamic mamillary nuclei might regulate the mechanisms of the skin microvessel permeability, the action being mediated through capsaicinsensitive neurons of the spinal ganglion.     

Chemical constituents from the roots of Caragana grandiflora (M. B.) DC. and their chemotaxonomic importance

A comprehensive phytochemical research on roots of Caragana grandiflora, a native plant to Iran, resulted in isolation of ten compounds including four phenolic compounds (2, 4, 5, 8), two fatty alcohols (1, 6), one fatty acid (9), one triterpene (3), one glyceride derivatives (7) and one fatty acid methyl ester (10), from which eight compounds (1, 2, 4–6 and 8–10) were isolated from the genus Caragana and two compounds (5 and 10) from the family Fabaceae, for the first time. All compounds (1–10) were described from Caragana grandiflora for the first time. Chemical structures of the purified compounds were identified through FT-IR, NMR and MSS, and spectral data comparison with literature reported evidences.Our findings provide valuable information in reporting the rare existence of natural fatty acid methyl ester (10) in the Fabaceae family. Moreover, the chemotaxonomic significance of these compounds was discussed.     

The fine structure of conidial development in the genus Torula. II. T. caligans (Batista and Upadhyay) M. B. Ellis and T. terrestris Mistra.

Conidia of Torula caligans (Batista & Upadhyay) M. B. Ellis comb.nov. and T. terrestris Misra were examined by transmission- and scanning-electron microscopy. Torula caligans produced four-celled conidia in which the central cells were distinctly larger than the basal and apical cells. Conidia of T. terrestris were 4- to 7-celled long and ellipsoidal in shape. Conidiogenous cells in both species developed melanin only within the lowermost part of the lateral walls while the other cells of the conidium were uniformly melanized around the circumference of the cell; melanin in these cells being deposited within, at least, half the width of the cell wall. In both species new conidia arose from evagination of the hyaline apex of the conidiogenous cell and are therefore blastoconidia. The systematic relationships between T. caligans and T. terrestris and other species of the genus Torula are discussed.     

Inhibition by methyl mercury chloride and mercuric chloride of the in vitro polymerization of microtubules

Mercury was tested at the same concentration but under two different forms, organic CH3HgCl and inorganic HgCl2, in order to compare its relative inhibitory effect on in vitro microtubules polymerization. Induced by GTP and glycerol 8 M, tubulin polymerization was completely inhibited by HgCl2 10(-3) M while a 75.8% inhibition was measured for CH3HgCl2 10(-3) M.     

Irregular antibody screening by Groupamatic at the Paris (C.N.T.S.) and Toulouse (C.R.T.S.) blood transfusion centers

We report here the experience of 3 years of irregular antibody automated screening with Groupamatic, that is to say of 661,511 samples tested in Paris and 269, 162 samples tested in Toulouse. The positive reactions in Paris were 16,296 (2.46%) out of which 2,021 irregular antibodies were identified (0.30%). The positive reactions in Toulouse were 8,266 (3.07%) out of which 2,138 irregular antibodies were identified (0,79%). The difference between the number of screened positive reactions and the identified one is due to false positive reactions (half of the cases) and to autoantibodies whose number is roughly the same than the number of identified alloantibodies. During the years 1970, 1971 and 1972, the irregular antibodies were systematically screened in Toulouse on all blood donors with a manual technique on opaline plate using enzyme treated red cell tests (papain). 7,147 positive reactions were detected, out of 240,080 tests (2.98%). 1,954 (0,81%) were alloantibodies and 1,529 (0.64%) autoantibodies; 3.455 were false positive reactions and 209 were non identified antibodies. These figures are superimposed with those obtained with Groupamatic during the following years, thus pointing out the interest of this equipment.     

The effect of salt acclimation of the water uptake and osmotic permeability of the skin of the toad (Bufo viridis, L.)

1. Water uptake in vivo, and water fluxes across the isolated skin were studied in salt (NaCl) acclimated toads. 2. Water uptake of acclimated toads maintained in the solution of acclimation, decreased with the environmental salinity. 3. The osmotic water permeability (Pos) of the skin increased upon salt (NaCl) acclimation, both in vivo and in vitro. 4. Pos of the skin of toads acclimated to non-permeant solutes such as sucrose (230 mmol/l) or mannitol (400 nmol/l), was greatly reduced. 5. Oxytocin (syntocinon) increased the Pos both in tap water and salt acclimated toads. In high salt (greater than 200 mmol/l NaCl) acclimated toads however, the increased Pos and water flux at larger osmotic gradients, could not be stimulated further by the hormone. 6. The adaptive nature of the selective changes in the permeability properties of the skin under salt acclimation conditions is discussed.