Anti-aggregation action of hypochlorite on the thrombocytes

Sodium hypochlorite at concentrations higher than 1 mM suppresses ADP-dependent aggregation of blood platelets. The effect was associated with the process of cell modification. Blood platelet aggregation may be depressed partially by ADP destruction. Products of ADP-sodium hypochlorite interaction may lead to the induction of blood platelet aggregation, which is not so intensive than the ADP-induced one.     

Effects of hypochlorite on cultured respiratory epithelial cells

Neutrophils and eosinophils are involved in the pathogenesis of many respiratory diseases. The enzymes myeloperoxidase and eosinophil peroxidase catalyze the reaction of H₂O₂ with Cl to produce the reactive oxygen species HOCl.

Normal human bronchial epithelial (NHBE) cells were exposed to 0.18-0.90 mM HOCl for 48 h, and studied with immunohistochemical, metabolic and morphological studies.

The ability of the cells to attach to each other and/or to the matrix was altered. Immunohistochemical studies showed a decreased amount of desmosomes and focal adhesion sites, although the morphology of the cells was not affected. The ability of the mitochondria to oxidize glucose was reduced. HOCl-exposed cells had an increased production of NO, probably by an increased activity of cNOS, due to increased intracellular Ca²⁺. The antioxidant N-acetylcysteine inhibited both the NO production and the effects of HOCl on glucose oxidation. The cNOS-inhibitor N-propyl-L-arginine inhibited HOCl-induced NO production. X-ray microanalysis showed an increase in the intracellular Na⁺/K⁺ ratio, which indicates cell damage.

In conclusion, exposure to HOCl results in cell detachment and metabolic alterations in normal human bronchial epithelial cells. Oxygen radicals could in part mediate the effects. Oxygen radicals could hence contribute to the observed epithelial damage in respiratory diseases.     

Effects of hypochlorite on cultured respiratory epithelial cells

Neutrophils and eosinophils are involved in the pathogenesis of many respiratory diseases. The enzymes myeloperoxidase and eosinophil peroxidase catalyze the reaction of H₂O₂ with Cl to produce the reactive oxygen species HOCl.

Normal human bronchial epithelial (NHBE) cells were exposed to 0.18–0.90 mM HOCl for 48 h, and studied with immunohistochemical, metabolic and morphological studies.

The ability of the cells to attach to each other and/or to the matrix was altered. Immunohistochemical studies showed a decreased amount of desmosomes and focal adhesion sites, although the morphology of the cells was not affected. The ability of the mitochondria to oxidize glucose was reduced. HOCl-exposed cells had an increased production of NO, probably by an increased activity of cNOS, due to increased intracellular Ca²⁺. The antioxidant N-acetylcysteine inhibited both the NO production and the effects of HOCl on glucose oxidation. The cNOS-inhibitor N-propyl-L-arginine inhibited HOCl-induced NO production. X-ray microanalysis showed an increase in the intracellular Na⁺/K⁺ ratio, which indicates cell damage.

In conclusion, exposure to HOCl results in cell detachment and metabolic alterations in normal human bronchial epithelial cells. Oxygen radicals could in part mediate the effects. Oxygen radicals could hence contribute to the observed epithelial damage in respiratory diseases.     

The use of gas-liquid chromatography in the analysis of neutral monosaccharides in hydrolysates of gastric mucopolysaccharides

1. Conditions are described for the separation and estimation of the neutral monosaccharides obtained on acidic hydrolysis of human gastric mucopolysaccharides. 2. The technique involves the formation of the trimethylsilyl derivatives of the sugars and the analysis of these by gas-liquid chromatography. 3. The monosaccharides estimated in gastric mucopolysaccharides by this technique were l-fucose, d-mannose, d-galactose and d-glucose. 4. The analytical values for glucose and fucose obtained by this method agreed well with values obtained by the glucose oxidase and thioglycollic acid methods respectively. 5. Evidence is presented which clearly indicates that gas-liquid chromatography is a faster, more sensitive and more convenient technique for the measurement of these compounds than any other in use at present.     

Studies on reaction of glutathionylcobalamin with hypochlorite. Evidence of protective action of glutathionyl-ligand against corrin modification by hypochlorite

Glutathionylcobalamin (GSCbl), a tight complex of glutathione (GSH) with cobalamin(III), is readily oxidized to aquacobalamin by hypochlorite. Corrin macrocycle remains unmodified in the presence of threefold excess of hypochlorite, whereas aqua- and cyanocobalamins are partially transformed to chlorinated species under the same conditions. The suggested mechanism of reaction between GSCbl and hypochlorite involves subsequent oxidation of thiol and amino groups and dissociation of oxidized glutathione from Co(III)-ion.     

Mechanism of action of biogenic chloramines and hypochlorite on initial aggregation of blood platelets

The antiaggregant action of two reactive oxidants N,N-dichlorotaurine (chloramine of biogenic type) and sodium hypochlorite on the initial ADP-induced aggregation of rabbit blood platelets has been studied. Platelet aggregation in the reconstructed platelet-rich plasma (PRP) was measured by the nephelometric method, and the aggregation index was an increase in the intensity of small-angle light scattering. The introduction of chloramine at comparatively small concentrations (no greater than 1 mM active chlorine) directly into the reconstructed platelet-rich plasma induces the suppression of the initial aggregation (formation of small aggregates) several times stronger than in the case of its preliminary incubation with plasma alone. This suggests that N,N-dichlorotaurine exerts its antiaggeregant action on the platelet-rich plasma by direct interaction with cells. The effects of the inhibition of platelet aggregation in two variants of introduction of high concentrations of N,N-dichlorotaurine do not significantly differ. In this case a great amount of residual chloramine remains in the plasma, which just induces the suppression of platelet aggregation during subsequent reconstruction of the platelet-rich plasma. Similar data have been obtained in the study of the antiaggregant action of hypochlorite. N,N-Dichlorotaurine and hypochlorite at final concentrations of 0.2-0.3 and 0.15 mM, respectively, inhibit strongly the initial aggregation of isolated platelets (approximately 2 x 10(8) cells in 1 ml) preliminarily activated for 1.5 min by the addition of 100-500 nM ADP. However, the antiaggregants show a more profound suppression of aggregation of unstimulated platelets. The antiaggregant effects of N,N-dichlorotaurine and hypochlorite are probably due to the oxidative modification of sulfur-containing groups in platelet plasmatic membrane.     

The effect of neutral nonadditive gene action on the quantitative index of population divergence

For neutral additive genes, the quantitative index of population divergence (Q(ST)) is equivalent to Wright's fixation index (F(ST)). Thus, divergent or convergent selection is usually invoked, respectively, as a cause of the observed increase (Q(ST) > F(ST)) or decrease (Q(ST) < F(ST)) of Q(ST) from its neutral expectation (Q(ST) = F(ST)). However, neutral nonadditive gene action can mimic the additive expectations under selection. We have studied theoretically the effect of consecutive population bottlenecks on the difference F(ST) - Q(ST) for two neutral biallelic epistatic loci, covering all types of marginal gene action. With simple dominance, Q(ST) < F(ST) for only low to moderate frequencies of the recessive alleles; otherwise, Q(ST) > F(ST). Additional epistasis extends the condition Q(ST) < F(ST) to a broader range of frequencies. Irrespective of the type of nonadditive action, Q(ST) < F(ST) generally implies an increase of both the within-line additive variance after bottlenecks over its ancestral value (V(A)) and the between-line variance over its additive expectation (2F(ST)V(A)). Thus, both the redistribution of the genetic variance after bottlenecks and the F(ST) - Q(ST) value are governed largely by the marginal properties of single loci. The results indicate that the use of the F(ST) - Q(ST) criterion to investigate the relative importance of drift and selection in population differentiation should be restricted to pure additive traits.     

The mechanisms of action of interleukin-1 on rabbit intestinal epithelial cells

Interleukin-1 (IL-1) is an inflammatory mediator that increases Cl- secretion in intestinal epithelial cells. To identify the signal transduction pathway(s) involved in IL-1's action, cells were treated with IL-1 and the levels of cyclooxygenase (COX) enzymes, prostaglandin E2 (PGE2) and phospholipase A2-activating protein (PLAP), and the activity of phospholipase A2 (PLA2) were measured. IL-1 caused concentration- and time-dependent increases in the levels of PLA2 activity, and/or in the levels of PLAP, COX-2 and PGE2. The IL-induced increase in PGE2 levels was biphasic, with the first peak due to the increase in PLAP levels, and the second peak due to the increase in COX-2 levels. This increase in PGE2 levels may provide a mechanism for acute and chronic inflammation in the intestine.     

Mechanism of the action of biogenic chloramines and hypochlorite on the initial aggregation of platelets

The antiaggregant effect of two reactive oxidants—N,N-dichlorotaurine (a biogenic chloramine) and sodium hypochlorite—on the initial ADP-induced aggregation of rabbit blood platelets was studied. Platelet aggregation in reconstituted platelet-rich plasma was measured nephelometrically; an increase in the intensity of small-angle light scattering served as an index of aggregation. Addition of chloramine at relatively small concentrations (no greater than 1 mM available chlorine) directly to the reconstituted platelet-rich plasma suppressed the initial aggregation (formation of small aggregates) several times more strongly than preincubation of native plasma with chloramine. This suggests that N,N-dichlorotaurine realizes its antiaggregant effect on the platelet-rich plasma by directly interacting with cells. The effects of the inhibition of platelet aggregation in two variants of addition of high concentrations of N,N-dichlorotaurine did not differ significantly. In this case, a large amount of residual unreacted chloramine remained in the plasma, which caused the suppression of platelet aggregation during subsequent reconstitution of the platelet-rich plasma. Similar data were obtained in studying the antiaggregant effect of hypochlorite. N,N-Dichlorotaurine and hypochlorite at concentrations of 0.2–0.3 and 0.15 mM, respectively, strongly inhibited the initial aggregation of isolated platelets (approximately 2·10⁸ cells/ml) preliminarily activated for 1.5 min by addition of 0.1–0.5 μM ADP. However, the antiaggregants had a more profound suppressive effect on the aggregation of unstimulated platelets. The antiaggregant effects of N,N-dichlorotaurine and hypochlorite probably stem from the oxidative modification of the sulfur-containing groups in platelet plasma membrane.     

The acid mucopolysaccharides of cattle retina

1. Two polysaccharides were isolated from the interstitial matrix surrounding the photoreceptor cells of cattle retina. They were liberated from this region of the tissue in a soluble form after agitation of whole retinas in 0.9% sodium chloride. One, which comprises two-thirds of the polysaccharides present, is a hyaluronidase-sensitive ;half-sulphated' chondroitin sulphate containing uronic acid, galactosamine and sulphate in the molar proportions 1.27:1.0:0.54. The other is a hyaluronidase-resistant non-sulphated heteropolysaccharide for which the name sialoglycan is proposed. It contains galactose, glucosamine and sialic acid in the molar proportions 2.4:1.0:0.4. Both polysaccharides contain only small amounts of nitrogen in excess of the amount calculated from their amino sugar and sialic acid content. 2. A similar combination of mucopolysaccharides is associated with the pigment epithelial-cell layer but in quantities only one-fifth of those present in the adjacent matrix area. 3. The ease with which they are released into aqueous media is consistent with the assumption that they are present in the extracellular spaces in both of these tissue layers. 4. The retinal residue left after removal of the two soluble polysaccharides is rich in amino sugar- and sialic acid-containing polymers, which appear to be firmly bound to the tissue fragments. 5. About one-third of the sialic acid and one-tenth of the amino sugar could be extracted with chloroform-methanol. The components in this fraction were tentatively identified as gangliosides. 6. Digestion of the chloroform-methanol-insoluble residue with Pronase yielded as the principal product a heteropolysaccharide containing 16.5% of glucosamine, 24.3% of neutral sugar (galactose plus fucose) and 18.1% of sialic acid. This substance has been classified as a sialoglycan of composition similar to (but not identical with) that of the soluble one isolated from the matrix area of the tissue.