The influence of vitamin C on systemic markers of endothelial and inflammatory cell activation in smokers and non-smokers.

OBJECTIVE AND DESIGN: To determine the influence of vitamin C supplementation (500 mg, bd, 14 days) on the circulating concentrations of soluble ICAM-1 (a marker of endothelial activation), neopterin (a marker of monocyte activation), and neutrophil elastase (a marker of neutrophil activation) in smokers and non-smokers in a randomised, double-blind, placebo-controlled trial in a hospital setting. SUBJECTS: Twenty smokers (serum cotinine > or = 20 ng ml(-1)) and 20 age- and gender-matched non-smokers (serum cotinine < or = 13.7 ng ml(-1)). RESULTS: At baseline, there was a significant elevation in the concentration of sICAM-1 in smokers (median 247, IQR 199 to 357 ng ml(-1)) compared to non-smokers (median 207, IQR 189 to 227 ng ml(-1); p = 0.014). Vitamin C supplementation did not influence the circulating concentrations of ICAM-1 or neopterin, or leukocyte elastase activity, in smokers, non-smokers, or in the total population. CONCLUSIONS: Markers of monocyte and neutrophil activation were not influenced by smoking status in this study population. However, sICAM-1 concentrations were significantly elevated in tobacco smokers, reflecting tobacco-induced vascular activation that is unaffected by Vitamin C supplementation.

Adjunctive systemic and locally delivered metronidazole in the treatment of periodontitis: a controlled clinical study.

OBJECTIVE: To compare clinical and microbiological responses following non-surgical treatment of moderate to advanced adult periodontitis using subgingival scaling with and without adjunctive topical or systemic metronidazole. DESIGN: A single blind randomised clinical trial of 90 subjects, stratified for periodontitis disease severity and smoking status, divided into three treatment groups: 1. Subgingival scaling using ultrasonic scalers and local anaesthesia; 2. Subgingival scaling using ultrasonic scalers and local anaesthesia plus seven days of systemic metronidazole (200 mg tds); 3. Subgingival scaling using ultrasonic scalers and local anaesthesia plus two applications of 25% metronidazole gel one week apart in all sites with probing depths more than 4 mm. Evaluations were made before treatment, and 8 weeks and 24 weeks post treatment. MAIN OUTCOME MEASURES: Probing depths, probing attachment levels and bleeding on probing were measured using a Florida probe. Bacterial morphotypes were evaluated with darkfield microscopy. Results were analysed for all sites with baseline probing depths equal to or greater than Florida probe recordings of 4.6 mm using analysis of variance. RESULTS: 84 subjects completed the trial and the three treatment groups did not differ at baseline for any clinical parameter. Mean probing depths were reduced following treatment by greater than 1.6 mm (Group 1 = 1.68 mm, Group 2 = 1.62 mm, Group 3 = 1.74 mm at six months post treatment) but no significant differences were detected between treatment groups at any time point. Similarly, no significant differences were detectable between treatments for changes in mean probing attachment levels, bleeding on probing, plaque scores or proportions of bacterial morphotypes. CONCLUSIONS: This study does not support the routine use of adjunctive metronidazole in the non-surgical treatment of periodontitis.

Nitric oxide generation. A predictive parameter of acute allograft rejection.

The L-arginine:nitric oxide (NO) biosynthetic pathway has been proposed as an important mediator in host defense mechanisms and may therefore play a role in the acute allograft response. We have studied NO generation in liver allograft rejection and determined its value in immunological monitoring. Stable end products of this pathway have been determined serially in 50 primary liver recipients and compared with 2 known mediators and markers of acute allograft rejection (IL-2R positive lymphocytes and circulating TNF alpha). Plasma concentrations of acid-labile nitrosocompounds (NOx), which increased during acute allograft rejection (P < 0.0001), correlated with rejection severity and were reduced after administration of supplemental high dose glucocorticoids. Concentrations were significantly lower in nonrejection graft complications but were elevated during episodes of sepsis. Correlations between plasma NOx levels and circulating TNF-alpha (r = 0.451, P < 0.001) and IL-2R-positive lymphocytes in peripheral blood (r = 0.781, P < 0.001) were demonstrated. In a logistic analysis of these variables, plasma NOx was the most predictive parameter of an episode of acute cellular rejection. Nitric oxide generation in FK506-treated patients was lower compared with patients receiving a CsA-based immunosuppression regimen and was associated with a reduced frequency of acute rejection in the FK506 group. These data are consistent with a role for NO in the cellular alloantigen immune response and indicate that monitoring of plasma levels of NOx may be useful in the detection of acute allograft rejection.

Cloning, characterization, and expression of a cDNA encoding an inducible nitric oxide synthase from the human chondrocyte.

Incubation of human articular chondrocytes with interleukin 1 beta results in the time-dependent expression of nitric oxide (NO) synthase. We report here the isolation of a cDNA clone which encodes a protein of 1153 amino acids with a molecular mass of 131,213 Da and a calculated isoelectric point of 7.9. CHO cells transfected with a plasmid harboring this cDNA clone expressed NO synthase activity that was inhibited by some L-arginine analogues. The deduced amino acid sequence of the human chondrocyte inducible NO synthase shows 51% identity and 68% similarity with the endothelial NO synthase and 54% identity and 70% similarity with the neuronal NO synthase. The similarity (88%) between the human chondrocyte NO synthase cDNA sequence and that reported for the murine macrophage suggests that the inducible class of enzyme is conserved between different cell types and across species.

A new technique of local anesthesia for panretinal photocoagulation.

We report a technique of local anesthetic administration used in 26 consecutive patients undergoing panretinal photocoagulation. A blunt-tipped irrigating cannula delivered 3 cc of anesthetic into the posterior sub-Tenon's space through a small opening in conjunctiva and Tenon's capsule. Immediate anesthesia, with no serious complications, was obtained in 38 of 40 eyes, facilitating administration of rapid, high-intensity laser burns. Although our experience with it is limited, we believe that this technique allows avoidance of many of the potential complications associated with the passage of a needle into the retrobulbar space.

The crucial role of physiological Ca2+ concentrations in the production of endothelial nitric oxide and the control of vascular tone.

1. The effect of varying the extracellular Ca2+ concentration on the basal and acetylcholine (ACh)-induced release of nitric oxide (NO) from the rabbit aorta was investigated by use of a superfusion bioassay system. 2. Changes between 0.5 and 2.0 mM in the concentration of Ca2+ superfusing the detector bioassay tissues or perfusing endothelium-denuded donor aortae had no effect on the tone of these tissues. 3. Increasing the concentration of Ca2+ perfusing endothelium-containing donor aortae from zero to 1.25 mM caused a transient (24 +/- 9 min), concentration-dependent basal release of NO, which was attenuated at higher concentrations of Ca2+ (1.5-2.0 mM). 4. The duration of the effect of Ca2+ on the basal release of NO was increased by a concomitant infusion of L-arginine (100 microM) through the donor aorta. 5. Changes in the concentration of Ca2+ between 0.5 and 2.0 mM had a similar biphasic effect on the release of NO induced by ACh, which was also maximal at 1.25 mM Ca2+. 6. When Ca2+ was removed from the Krebs buffer perfusing the donor aorta, the basal release of NO declined within 2 min. In contrast, the release of NO induced by ACh declined progressively over 60 min. 7. Thus changes in the concentration of Ca2+ around the physiological range modulate the synthesis of NO by the vascular endothelium and consequently, vascular tone. This may account for the effects of dietary Ca2+ supplements on the control of some hypertensive states.

Steatosis and cirrhosis in an obese diabetic. Resolution of fatty liver by fasting.

A 54-year-old woman with obesity, type II diabetes mellitus, hyperlipidemia, and massive hepatomegaly was found to have severe steatosis and cirrhosis on liver biopsy. Complete evaluation led to the diagnosis of fatty cirrhosis associated with obesity and diabetic mellitus. She underwent four months of fasting with a protein-carbohydrate and vitamin-mineral liquid supplement to control her weight and metabolic abnormalities and to evaluate the effect of this diet on her liver disease. She lost 40 pounds to ideal body weight, normalized her serum glucose and lipids, and decreased total liver height by one third. Liver biopsy at the completion of her diet showed inactive cirrhosis and complete resolution of steatosis. Supplemented fasting with only modest weight loss can safely resolve fatty liver in obese diabetics with nonalcoholic steatosis and cirrhosis. Aggressive dietary approaches to achieve long-term weight loss deserve study in this subgroup of diabetics with unexplained chronic liver disease.