Effect of sulphite on the oxidative metabolism of human neutrophils: Studies with lucigenin- and luminol-dependent chemiluminescence

To assess the effect of sulphite on the oxidative metabolism of human neutrophils, chemiluminescence (CL) measurements were performed using lucigenin and luminol as chemiluminigenic probes. Lucigenin-dependent CL was used for measuring superoxide anion (O) production, and luminol-dependent CL was used for determination of myeloperoxidase (MPO)-connected processes. With sulphite concentrations of 0.01 to 1 mmol/L, resting neutrophils showed an up to sixfold increase of lucigenin-dependent CL, but only a 1.9-fold increase of luminol-dependent CL. Subsequent stimulation of sulphite-treated neutrophils with phorbol myristate acetate (PMA) (soluble stimulant) or zymosan (particulate stimulant) resulted in an additional significant increase of lucigenin-dependent CL compared to stimulated control cells, whereas luminol-dependent CL increased slightly by 0.01 mmol/L sulphite and decreased then continuously. Sulphite concentrations above 1 mmol/L decreased both lucigenin- and luminol-dependent CL of resting and PMA- or zymosan-stimulated neutrophils. Lucigenin-dependent CL of sulphite-treated and subsequently stimulated neutrophils was strongly inhibited by extracellularly added superoxide dismutase, whereas luminol-dependent CL was markedly reduced by the MPO inhibitor azide. The intracellular activity of MPO in neutrophils stimulated with PMA in the presence of sulphite (2 mmol/L) was reduced by 55%. Sulphite (0.1 mmol/L) also inhibited strongly the activity of MPO in a cell-free system. These results indicate that micromolar concentrations of sulphite exert a stimulating effect on the O production of neutrophils extracellularly, but have an inhibitory effect on MPO-catalysed reactions intracellularly.     

Phenotypic variability and therapeutic implications of Candida species in patients with oral lichen planus

We investigated the prevalence and phenotypic variation of Candida species in oral lichen planus (OLP) and the therapeutic implications of our findings. Eighty patients with clinically and histopathologically confirmed cases of OLP (64 non-erosive, 16 erosive) and a control group of 80 healthy individuals with no predisposing factors for oral candidiasis were examined for evidence of Candida infection. Oral swabs and smears were obtained for cytology and culture. Identification, speciation and antifungal susceptibility tests of Candida isolates were performed using an automated microbial identification system. Fifty percent of erosive OLP cases, 28% of non-erosive cases and none of the controls showed evidence of Candida. Candida albicans was found predominantly in non-erosive OLP, while other Candida species were predominate in erosive OLP. Non-Candida albicans isolates (C. glabrata, C. krusei) were resistant to the commonly used antifungals, clotrimazole and fluconazole. Candida infection is common in cases of OLP. We recommend antifungal sensitivity testing prior to antifungal therapy for the erosive form of OLP.     

Cyclic AMP induces synthesis of prostaglandin E1 in platelets

Although platelets are known to synthesize small amounts of prostaglandin E1 the control of the formation of this prostanoid has not been investigated. Incubation of human platelet-rich plasma with various compounds which are known to increase cyclic AMP concentration in platelets and inhibit platelet aggregation also increased intracellular prostaglandin E1 synthesis. The prostaglandin E1 was isolated by high pressure liquid chromatography and definitively identified by negative and positive ionization mass spectroscopy. The amounts of prostaglandin E1 formed were proportional to the concentration of cyclic AMP in platelets. Prostacyclin (10 nM) which is the most potent stimulator of cyclic AMP formation increased intracellular cyclic AMP by 4.6 fold and prostaglandin E1 level by 3 fold over the basal levels. Addition of theophylline, a cyclic AMP phosphodiesterase inhibitor, together with prostacyclin increased cyclic AMP concentration 8.7-fold and prostaglandin E1 level 12-fold compared to basal concentrations. Dibutyryl cyclic AMP (2 mM) and 8-bromo cyclic AMP (0.1 mM) increased prostaglandin E1 levels by 3 fold and 2 fold over the basal level, respectively. Prostaglandin D2 (3 microM) when added to platelet-rich plasma increased the cyclic nucleotide levels by 2 fold concomitant with 2 fold increase in prostaglandin E1 concentration. In contrast prostaglandin E2 or prostaglandin F2 alpha which had no effect on cyclic AMP level did not affect the prostaglandin E1 synthesis. Addition of 2',5'-dideoxyadenosine, an inhibitor of adenylate cyclase, to platelet-rich plasma inhibited both the increase of intracellular prostaglandin E1 and cyclic AMP levels induced by prostacyclin.     

Plasma neurotensin release and gastric emptying in the dumping syndrome

Seventy-three patients were studied after ingesting a liquid glucose meal, tagged with ¹¹³Indium. Nineteen of these patients were awaiting surgery for their duodenal ulcer, while 54 were studied postoperatively, 25 of whom experienced troublesome postprandial (dumping) symptoms in their daily lives. The radioactive marker emptied significantly faster in the symptomatic patients than in the symptomfree, pre and post-operative groups (initial emptying rate 3.45 ± 0.23, compared with 1.16 ± 0.19 and 1.27 ± 0.15% fall in counts/min respectively; p < 0.01). Initial (20 min) rises in the plasma concentrations of neurotensin-like immunoreactivity measured during the test correlated significantly with the rate of gastric emptying in all patients, being greatest in patients with dumping symptoms. Physiological concentrations of neurotensin have been shown to delay gastric emptying. The excessive rise in plasma neurotensin-like immunoreactivity in patients with dumping symptoms, presumably occuring as a result of the rapid passage of nutrients to the neurotensin-rich ileum, may possibly have a compensatory role in slowing further emptying from the stomach.     

Surgical Treatment of Tumours of the Eyelids

Sixty-five patients, in whom eyelid cysts and tumours were surgically excised and examined histopathologically, were followed up. The general principles of treatment are outlined. The procedures used in the reconstruction of the eyelids, which depended upon the extent of lid-loss; the results obtained; and the complications encountered, are described.Surgical excision with subsequent repair is preferred to radiation therapy in view of the unique accessibility, general low malignancy and infrequent metastases of these tumours. Such excision and repair produces a better cosmetic and functional result.     

Effect of kinetin on water relations,photosynthesis, respiration and chlorophyll and nucleic acid contents of wheat (Triticum aestivum L.) grown under salinity

The effect of kinetin (10 g m^-3) presowing seed soaking treatment on water relations, chlorophyll (Chl) and nucleic acid contents, and photosynthetic and respiration rates in wheat (Triticum aestivum L.) grown in a greenhouse under three salinity levels (i.e. 0,6 and 9 dS m^-1 ECe) was studied. Relative water content and osmotic potential showed a progressive decline with increase in the salinity but there was an increase in chlorophyll (a+b) content in the leaves. Salinity decreased RNA content and net photosynthetic and respiration rates. Seed soaking either in water or kinetin enhanced the relative water content of leaves but reduced osmotic potential under both saline and non-saline conditions.     

Stereoselective synthesis of (24R and 24S) 5 beta-cholestane-3 alpha,7 alpha,12 alpha,24,25-pentols and (25R and 25S) 5 beta-cholestane-3 alpha,7 alpha,12 alpha,25,26-pentols using a modified osmium-catalyzed Sharpless asymmetric dihydroxylation process.

Described herein are the stereoselective syntheses of the (24R, 24S) and (25R, 25S) isomers of 5 beta-cholestane-3 alpha,7 alpha,12 alpha,24,25-pentols and 5 beta-cholestane-3 alpha,7 alpha,12 alpha,25,26-pentols by using a modified osmium-catalyzed Sharpless asymmetric dihydroxylation process. Also presented herein are the results of lanthanide-induced CD Cotton effect measurements and 1H- and 13C-nuclear magnetic resonance studies of (24R, 24S) and (25R, 25S)-5 beta-cholestanepentols and their derivatives. These compounds were required to study the biosynthesis of cholic acid from cholesterol.     

Isolation and identification of 1,23-dihydroxy-24,25,26,27-tetranorvitamin D3, a new metabolite of 1,25-dihydroxyvitamin D3 produced in rat kidney

A new metabolite of vitamin D3 was produced in vitro by perfusing rat kidneys with 1,25-dihydroxyvitamin D3 (4 X 10(-6) M). It was isolated and purified from the lipid extract of the kidney perfusate by high-performance liquid chromatography. By means of ultraviolet absorption spectrophotometry, mass spectrometry, chemical derivatization, and chemical synthesis, the new metabolite was identified as 1,23-dihydroxy-24,25,26,27-tetranorvitamin D3. Along with the new metabolite, three other previously identified metabolites, namely, 1,24,25-trihydroxyvitamin D3, 1,25-dihydroxy-24-oxovitamin D3, and 1,23,25-trihydroxy-24-oxovitamin D3, were also isolated. The new metabolite was also formed when 1,23,25-trihydroxy-24-oxovitamin D3 was used as the substrate. Thus, the new metabolite fits into the following metabolic pathway: 1,25-dihydroxyvitamin D3----1,24(R),25-trihydroxyvitamin D3----1,25-dihydroxy-24-oxovitamin D3----1,23,25-trihydroxy-24-oxovitamin D3----1,23-dihydroxy-24,25,26,27-tetranorvitamin D3. Further, we used 1 alpha,25-dihydroxy[1 beta-3H]vitamin D3 in the kidney perfusion system and demonstrated 1,23-dihydroxy-24,25,26,27-tetranorvitamin D3 as the major further metabolite of 1,25-dihydroxyvitamin D3, circulating in the final perfusate when kidneys were perfused with 1,25-dihydroxyvitamin D3 (6 X 10(-10) M) for 4 h. The biological activity of 1,23-dihydroxy-24,25,26,27-tetranorvitamin D3 (C-3 alcohol) and its metabolic relationship to 1-hydroxy-23-carboxy-24,25,26,27-tetranorvitamin D3 (calcitroic acid or C-23 acid), the other previously identified side-chain cleavage metabolite of 1,25-dihydroxyvitamin D3, are unknown and are presently undergoing investigation.     

Rotavirus spike structure and polypeptide composition.

Negatively stained preparations of rotavirus imaged with a low dose of electrons provide sufficient contrast to reveal surface projections or spikes. The number of spikes found projecting from different particles indicates that not all 60 peripentonal sites are occupied. Treatment at pH 11.2 with 250 mM ammonium hydroxide specifically removes the spikes, yielding smooth double-shelled particles of the same diameter as that of the native virus. Protein analysis confirms that the released spikes are composed of polypeptide VP4 (or its two cleavage products VP5* and VP8*) and that the smooth particle retains the other major outer shell protein VP7. Spikeless particles can be decorated by a monoclonal antibody specific for the major immunodominant neutralizing domain of VP7, implying that removal of the spikes does not denature the VP7 that is retained on the surface of the smooth particle.     

Protective Vascular and Cardiac Effects of Inducible Nitric Oxide Synthase in Mice with Hyperhomocysteinemia

Diet-induced hyperhomocysteinemia produces endothelial and cardiac dysfunction and promotes thrombosis through a mechanism proposed to involve oxidative stress. Inducible nitric oxide synthase (iNOS) is upregulated in hyperhomocysteinemia and can generate superoxide. We therefore tested the hypothesis that iNOS mediates the adverse oxidative, vascular, thrombotic, and cardiac effects of hyperhomocysteinemia. Mice deficient in iNOS (Nos2−/−) and their wild-type (Nos2+/+) littermates were fed a high methionine/low folate (HM/LF) diet to induce mild hyperhomocysteinemia, with a 2-fold increase in plasma total homocysteine (P<0.001 vs. control diet). Hyperhomocysteinemic Nos2+/+ mice exhibited endothelial dysfunction in cerebral arterioles, with impaired dilatation to acetylcholine but not nitroprusside, and enhanced susceptibility to carotid artery thrombosis, with shortened times to occlusion following photochemical injury (P<0.05 vs. control diet). Nos2−/− mice had decreased rather than increased dilatation responses to acetylcholine (P<0.05 vs. Nos2+/+ mice). Nos2−/− mice fed control diet also exhibited shortened times to thrombotic occlusion (P<0.05 vs. Nos2+/+ mice), and iNOS deficiency failed to protect from endothelial dysfunction or accelerated thrombosis in mice with hyperhomocysteinemia. Deficiency of iNOS did not alter myocardial infarct size in mice fed the control diet but significantly increased infarct size and cardiac superoxide production in mice fed the HM/LF diet (P<0.05 vs. Nos2+/+ mice). These findings suggest that endogenous iNOS protects from, rather than exacerbates, endothelial dysfunction, thrombosis, and hyperhomocysteinemia-associated myocardial ischemia-reperfusion injury. In the setting of mild hyperhomocysteinemia, iNOS functions to blunt cardiac oxidative stress rather than functioning as a source of superoxide.