Oral Healthcare Utilization Factors Shaping the Perceived Oral Health Outcome Among Gond Tribes of Chhattisgarh: A Cross-Sectional Study Based on Andersen's Behavioral Model

INTRODUCTION

The Gonds are a highly ancient and expansive tribal community, ranking among the largest in the world. A review of the literature has suggested that they are more vulnerable to oral diseases and are less inclined to utilize oral health services due to the comprehensive approach that considers the socioeconomic, cultural, and structural factors affecting the Gond community's access to oral health services. Tribal health requires action in the health sector. Utilization is an essential marker of the health status of any population and is necessary to bridge the gap between tribes and the wider portion of the community. Hence, this study was conducted among the Gond tribes of Chhattisgarh to evaluate the oral healthcare utilization factors shaping the perceived oral health outcome using Andersen's behavior model.

MATERIALS AND METHODS

This cross-sectional study was carried out among 400 Gond tribes residing in villages of Chhattisgarh. Data was collected through a standardized questionnaire, adapted from Andersen's behavioral model of healthcare utilization during house-to-house survey. The questionnaire included predisposing, enabling, perceived, and evaluated need factors. Oral health status for evaluated need was assessed using the World Health Organization (WHO) Oral Health Assessment form (1997), and the perceived oral health outcome was measured using Oral Health Impact Profile-14 (OHIP-14). Results were computed using descriptive statistics, chi-square test, and one-way analysis of variance (ANOVA). Multivariate analysis was done using binomial logistic regression.

RESULTS

The dental visit in the past one year was only 14%. The findings of logistic regression revealed that the perceived oral health outcome was significantly associated with age, occupation, and positive belief in the efficacy of dentist, perceived need, and presence of dental caries.

CONCLUSION

The findings of the present study support Andersen's behavioral model and suggest that there is an interrelationship of predisposing characters, predisposing health beliefs, and enabling need factors that determine the likelihood of use of services, which in turn determines the good or bad oral health outcome.

Effect of Scaling and Root Planing in Conjunction with Antimicrobial Therapy on Glycated Hemoglobin Levels in Type 2 Diabetes Mellitus Patients

Background

Scaling and root planing with systemic doxycycline had an effect on blood glucose levels in type 2 diabetes patients, according to the results of a glycosylated hemoglobin assay. The trial was conducted to determine whether periodontal therapy affected blood sugar regulation as a result of this finding.

Methods

A total of 60 people with type 2 diabetes (diabetes mellitus not caused by insulin deficiency) were split into three groups. Group I (control group) consists of patients who are only taking an oral anti-diabetic medication. Patients on an oral anti-diabetic drug plus scaling and root planing make up group II. Patients on an oral anti-diabetic drug, scaling, root planing, and doxycycline constitute Group III. The patients were re-evaluated for glycated hemoglobin levels and periodontal status using the clinical parameters of gingival index by Loe and Silness and clinical attachment level at baseline, 30th, 60th, and 90th day.

Results

Compared with group II, the findings showed a statistically significant decrease in glycated hemoglobin values (p =0.001) and improvements in clinical attachment level (p =0.022, 0.05) and gingival index (p = 0.009.,01) in group III. In the control group (group I), no such finding was made. The average gingival index, however, increased statistically significantly (p = 0.032, 0.05).

Conclusion

Various studies have been showing the benefits of non-surgical periodontal therapy as a benefit for improving the overall glycemic status of the patient. Non-surgical mechanical periodontal therapy combined with systemic administration of antimicrobials such as doxycycline enhances the metabolic status of type 2 diabetes mellitus patients better than non-surgical mechanical periodontal therapy alone.

POS0885 HYPOCHROMIC ERYTHROCYTES AS PROGNOSTIC INDICATOR OF SURVIVAL AMONG PATIENTS WITH SYSTEMIC SCLEROSIS SCREENED FOR PULMONARY HYPERTENSION

Background

Iron deficiency is frequent among patients with systemic sclerosis (SSc), particularly among those with pulmonary hypertension (PH). First data indicate prognostic importance of hypochromic erythrocytes (HRC) >2% among patients with PH1. Hence, the aim of this study was to investigate the predictive value of HRC in SSc patients screened for PH.

Objectives

The objective of this study was to investigate the predictive value of HRC in SSc patients screened for PH.

Methods

In this retrospective, single-center cohort study SSc patients screened for PH were included. Clinical characteristics, laboratory and pulmonary functional parameters associated with the prognosis of SSc were analysed using uni- and multivariable analysis.

Results

A total of 280 SSc patients were screened, 171 were included in the analysis having complete data of iron metabolism (79% female, 61.0±12.9 years of age, 73.2% limited cutaneous SSc, 56 manifest PH and 112 pulmonary fibrosis). The patients were followed for 2.4±1.8 (median 2.4) years. HRC >2% at baseline was significantly associated with worse survival in the uni- (p=0.018) and multivariable analysis (p<0.0001). Overall 34.5% of the patients suffered from iron deficiency and 22% received iron substitution during follow-up. HRC >2% was identified as independent predictor of mortality, for patients with and without pulmonary manifestations of SSc.

Conclusion

This study detected for the first time that HRC >2% is an independent prognostic predictor and can possibly be used as a biomarker among SSc-patients. Further studies are needed to confirm these results.

References

[1]Xanthouli P, Theobald V, Benjamin N, Marra AM, D’Agostino A, Egenlauf B, Shaukat M, Ding C, Cittadini A, Bossone E, Kögler M, Grünig E, Muckenthaler MU, Eichstaedt CA. Prognostic impact of hypochromic erythrocytes in patients with pulmonary arterial hypertension. Respir Res. 2021 Nov 9;22(1):288. doi: 10.1186/s12931-021-01884-9.

Disclosure of Interests

Panagiota Xanthouli Speakers bureau: MSD and OMT, outside the submitted work, Ojan Gordjani: None declared, Christina Eichstaedt: None declared, Nicola Benjamin Speakers bureau: Actelion pharmaceuticals, Bayer HealthCare and MSD., Benjamin Egenlauf Speakers bureau: Actelion, MSD, Bayer and OMT outside the submitted work, Satenik Harutyunova Speakers bureau: Bayer, MSD, Actelion and GSK, outside the submitted work., Alberto Marra Speakers bureau: Bayer/MSD outside the submitted work, Vivienne Theobald: None declared, Nicklas Milde: None declared, Christian Nagel Speakers bureau: Actelion, MSD, Boehringer, Novartis, Bayer, and AstraZeneca, Norbert Blank Speakers bureau: MSD, GSK, Actelion and Bayer Vital., Consultant of: MSD, GSK, Actelion and Bayer Vital., Hanns-Martin Lorenz Speakers bureau: AbbVie, BMS, Pfizer, Cellgene, Medac, GSK, Roche, Chugai, Novartis, UCB, Janssen-Cilag, AstraZeneca, and Lilly (less than $10,000 each) and research support from AbbVie, MSD, BMS, Cellgene, Medac, GSK, Roche, Chugai, Novartis, UCB, Janssen-Cilag, AstraZeneca, Lilly, Baxter, SOBI, Biogen, Actelion, Bayer Vital, Shire, Octapharm, Sanofi, Hexal, Mundipharm, and Thermo Fisher, Consultant of: AbbVie, BMS, Pfizer, Cellgene, Medac, GSK, Roche, Chugai, Novartis, UCB, Janssen-Cilag, AstraZeneca, and Lilly (less than $10,000 each) and research support from AbbVie, MSD, BMS, Cellgene, Medac, GSK, Roche, Chugai, Novartis, UCB, Janssen-Cilag, AstraZeneca, Lilly, Baxter, SOBI, Biogen, Actelion, Bayer Vital, Shire, Octapharm, Sanofi, Hexal, Mundipharm, and Thermo Fisher, Ekkehard Grünig Speakers bureau: Actelion, Bayer AG, and MSD; grants from GSK, Novartis, and United Therapeutics; and personal fees from SCOPE, OrPha Swiss GmbH, and Zurich Heart House, Consultant of: Actelion, Bayer AG, and MSD; grants from GSK, Novartis, and United Therapeutics; and personal fees from SCOPE, OrPha Swiss GmbH, and Zurich Heart House

AB0687 Prognostic meaning of right ventricular function and reserve in patients with systemic sclerosis

Background

The delay of the diagnosis of pulmonary hypertension (PH) in patients with systemic sclerosis (SSc) leads to severe impairment of survival.

Objectives

The objective of this study was to investigate the prognostic impact of right ventricular (RV) function at rest and during exercise on survival in patients with SSc presenting for screening for PH.

Methods

Data from SSc patients who underwent routinely performed examinations for PH screening including echocardiography and right heart catheterization at rest and during exercise were analyzed. Uni- and multivariable analyses were performed to identify prognostic parameters in SSc and to compare them to known prognostic predictors.

Results

Out of 285 SSc patients screened for PH, 225 patients (81.3% female, mean age 58.1±13.0 years, 68% limited cutaneous SSc, WHO-FC II-III 74%, 24 manifest PH) were included in the analysis. During an observation period of 3.2±2.7 (median 2.6) years 35 patients died. Tricuspid annular plane systolic excursion ≤18 mm (p=0.0004), increase of cardiac index (CI) during exercise ≤ 2 l/min (p=0.0002), RV output reserve >3 mmHg/l/min (p=0.001), peak CI ≤ 5.5l/min (p=0.01), pulmonary arterial compliance >2 ml/mmHg (p=0.0005) and qualitative RV function at rest (p<0.0001) significantly predicted survival. In the multivariable analysis, RV function at rest, diffusion capacity for carbon monoxide < 65% predicted and CI increase <2 l/min/m2 were identified as independent prognostic predictors and had >70% sensitivity and specificity to predict development of pulmonary vascular disease (PVD) during follow-up.

Conclusion

This study demonstrates that assessment of RV function at rest and during exercise may provide crucial information to identify SSc patients who are at a high risk of an impaired survival and development of PVD.

References

[1]Brown ZR, et al. Screening for pulmonary arterial hypertension in systemic sclerosis: Now or never!. Eur J Rheumatol. 2020;7(Suppl 3):S187-S192.

Disclosure of Interests

Panagiota Xanthouli Speakers bureau: MSD and OMT, outside the submitted work, Julia Miazgowski: None declared, Nicola Benjamin Speakers bureau: Actelion pharmaceuticals, Bayer HealthCare and MSD outside the submitted work., Ojan Gordjani: None declared, Benjamin Egenlauf Speakers bureau: Actelion, MSD, Bayer and OMT (less than $10,000 each)., Satenik Harutyunova Speakers bureau: Bayer, MSD, Actelion and GSK, outside the submitted work., Rebekka Seeger: None declared, Alberto Marra Speakers bureau: MSD, Norbert Blank Speakers bureau: MSD, GSK, Actelion and Bayer Vital., Hanns-Martin Lorenz Speakers bureau: AbbVie, BMS, Pfizer, Cellgene, Medac, GSK, Roche, Chugai, Novartis, UCB, Janssen-Cilag, AstraZeneca, and Lilly (less than $10,000 each) and research support from AbbVie, MSD, BMS, Cellgene, Medac, GSK, Roche, Chugai, Novartis, UCB, Janssen-Cilag, AstraZeneca, Lilly, Baxter, SOBI, Biogen, Actelion, Bayer Vital, Shire, Octapharm, Sanofi, Hexal, Mundipharm, and Thermo Fisher, Consultant of: AbbVie, BMS, Pfizer, Cellgene, Medac, GSK, Roche, Chugai, Novartis, UCB, Janssen-Cilag, AstraZeneca, and Lilly (less than $10,000 each) and research support from AbbVie, MSD, BMS, Cellgene, Medac, GSK, Roche, Chugai, Novartis, UCB, Janssen-Cilag, AstraZeneca, Lilly, Baxter, SOBI, Biogen, Actelion, Bayer Vital, Shire, Octapharm, Sanofi, Hexal, Mundipharm, and Thermo Fisher, Ekkehard Grünig Speakers bureau: Actelion, Bayer AG, and MSD; grants from GSK, Novartis, and United Therapeutics; and personal fees from SCOPE, OrPha Swiss GmbH, and Zurich Heart House, Consultant of: Actelion, Bayer AG, and MSD; grants from GSK, Novartis, and United Therapeutics; and personal fees from SCOPE, OrPha Swiss GmbH, and Zurich Heart House, Christina Eichstaedt: None declared

Renal nitrate clearance in chronic kidney disease

BACKGROUND

Nitric oxide (NO) is rapidly oxidised in humans to nitrite and nitrate, with nitrate being present in much greater abundance. These oxidation products can be recycled back into nitric oxide via a complex entero-salivary pathway, thus preserving NO activity. Approximately 65% of circulating nitrate is excreted in the urine in 48 h, with the excretory pathway of the remainder unknown. The effect of declining renal function on nitrate clearance is unknown METHODS: Forty five subjects, 21 M, 24F, median age 69 (range 27-75 years) with renal function assessed by CKD-EPI eGFR between 9 and 89 ml/min/1.73 m² completed the study. Following a 24 h low nitrate diet a microplate spectrophotometric method was employed to measure plasma nitrate concentration and 24 h urinary nitrate excretion were measured to determine renal nitrate clearance.

RESULTS

There was a strong positive correlation between urinary nitrate clearance and eGFR, (Spearman R = 0.7665, p < 0.0001) with a moderate negative correlation between plasma nitrate concentration and CKD-EPI eGFR, (Spearman's R = -0.37, p = 0.012). There was a trend between fractional excretion of nitrate and CKD-EPI eGFR (ml/min/1.73 m²) Spearman's R 0.27, p = 0.07 though this did not reach statistical significance. Plasma nitrate concentration and serum creatinine concentration were positively correlated, Spearman's R = 0.39, p = 0.008.

CONCLUSIONS

We have observed a strong positive association between renal nitrate clearance and renal function such that plasma nitrate rises as renal function falls. Fractional excretion of nitrate appears to decline as renal function falls. As such, urinary nitrate excretion is unlikely to be a reliable marker of endogenous NO synthesis in settings where renal function is altered.

P3676Hemodynamic phenotypes in systemic sclerosis patients screened for pulmonary hypertension (PH): impact of the new definition of PH

Background

Patients with systemic sclerosis (SSc) are at high risk of developing concomitant pulmonary hypertension (PH) which has a crucial impact on the patients' symptoms, quality of life and prognosis.

Purpose

The aim of this study was to analyse the impact of the new hemodynamic definition of precapillary PH as proposed at the 2018 World Symposium on PH in Nice in patients with SSc. Although recent data suggest that PVR >2 WU could be considered as abnormal in the new definition a conservative cut-off value of PVR ≥3 WU has been used.

Methods

SSc-patients were screened for PH using clinical assessments as WHO-functional class, 6 minute walking distance and right heart catheterisation. Patients were divided into hemodynamic subgroups according to their mean pulmonary arterial pressure (mPAP) values with mPAP ≤20 mmHg, 21–24 mmHg and ≥25 mmHg. These subgroups were further divided according to their pulmonary vascular resistance (PVR) with PVR <3 WU or ≥3 WU.

Results

One-hundred-twenty-two patients (79% female, age 57.6±12.7 years, 6MWD 439.5±98.1 meters, 70% diffuse cutaneous SSc, 30% limited cutaneous SSc, 53% WHO-FC II, 25% WHO-FC III) who were prospectively screened for PH were included in the analysis (Figure 1). Among them 26 had a symptomatic manifest PH using the cut-off value of mPAP ≥25 mmHg. Only half of this group presented with PVR ≥3 WU, the others had PVR <3 WU. Eight of these 26 PH-patients presented with PH due to left heart disease. Out of 21 patients with mildly elevated mPAP 21–24 mmHg, two (10%) met the new definition criteria of PH (pulmonary arterial wedge pressure <15 mmHg, mPAP 23 and 24 mmHg, PVR 3.0 and 3.2 WU, CI 2.2 L/min/m2 both, WHO-FC II both, respectively). Out of 75 patients with mPAP <21 mmHg, three presented with PVR ≥3 WU.

Overview of systemic sclerosis patients

Conclusions

The new definition of precapillary pulmonary hypertension may on the one hand allow detecting an additional 10% of PH patients with mild elevated mPAP. On the other hand, eight of 13 patients (62%), who met the former definition of pulmonary arterial hypertension, would be classified as “normal” due to a lack of increase in PVR according to the new definition. The data of this study suggest that for SSc-patients the cut-off value of mPAP >20 mmHg is useful, but the criteria of PVR ≥3 WU may be too strict.

Further studies with larger sample sizes will be needed to better characterise these hemodynamic subgroups and to define the extent of pulmonary vascular disease and treatability.

Clinical and radiological outcome following pneumothorax after endoscopic lung volume reduction with valves

INTRODUCTION

Valve implantation has evolved as a therapy for patients with advanced emphysema. Although it is a minimally invasive treatment, it is associated with complications, the most common being pneumothorax. Pneumothorax occurs due to the rapid target lobe volume reduction and may be a predictor of clinical benefit despite this complication.

OBJECTIVE

The objective of this study was to conduct an exploratory data analysis of patients who developed a pneumothorax following endoscopic valve therapy for emphysema.

MATERIALS AND METHODS

This study performed a retrospective evaluation of pneumothorax management and the impact of pneumothorax on clinical outcomes in 70 patients following valve therapy in 381 consecutive patients.

RESULTS

Pneumothorax rate following valve therapy was 18%. Pneumothorax management consisted of chest tube insertion, valve removal, and surgical intervention in 87% (61/70), 44% (31/70), and 19% (13/70) of the patients, respectively. Despite pneumothorax, patients experienced modest but significant improvements in lung function parameters (forced expiratory volume in 1 second: 55±148 mL, residual volume: -390±964 mL, total lung capacity: -348±876; all P<0.05). Persistent lobar atelectasis 3 months after recovering from pneumothorax, which was associated with relevant clinical improvement, was observed in only 21% (15/70) of the patients.

CONCLUSION

Pneumothorax is a frequent severe complication following valve therapy that requires further intervention. Nevertheless, the pneumothorax does not impair the clinical status in the majority of patients. Patients with lobar atelectasis benefit after recovering from pneumothorax in terms of lung function parameters.

Acidified nitrite as a potential antifungal agent

The use of acidified nitrite as a potential antifungal agent was investigated by exposing clinical isolates of Candida albicans, Candida glabrata, Candida tropicalis, Cryptococcus neoformans, Aspergillus fumigatus and Rhodotorula to varying concentrations of acidified nitrite at different pH levels to determine the minimal fungicidal concentration after 10 min exposure.

Protective effect of salivary nitrate and microbial nitrate reductase activity against caries

To test the hypothesis that a combination of high salivary nitrate and high nitrate-reducing capacity are protective against dental caries, 209 children attending the Dental Institute, Barts and The London NHS Trust were examined. Salivary nitrate and nitrite levels, counts of Streptococcus mutans and Lactobacillus spp., and caries experience were recorded. Compared with control subjects, a significant reduction in caries experience was found in patients with high salivary nitrate and high nitrate-reducing ability. Production of nitrite from salivary nitrate by commensal nitrate-reducing bacteria may limit the growth of cariogenic bacteria as a result of the production of antimicrobial oxides of nitrogen, including nitric oxide.

In vitro killing of Mycobacterium ulcerans by acidified nitrite

Mycobacterium ulcerans, which causes Buruli ulcer, was exposed to acidified nitrite or to acid alone for 10 or 20 min. Killing was rapid, and viable counts were reduced below detectable limits within 10 min of exposure to 40 mM acidified nitrite. M. ulcerans is highly susceptible to acidified nitrite in vitro.

Pilot randomized double-blind trial of treatment of Mycobacterium ulcerans disease (Buruli ulcer) with topical nitrogen oxides

Mycobacterium ulcerans disease (Buruli ulcer) is a serious ulcerating skin disease which is common in many tropical countries. Standard treatment, by extensive excision and skin grafting, is not available in rural communities where the disease is common. We evaluated the efficacy and safety of treatment with topical nitrogen oxides. Thirty-seven patients with a clinical diagnosis of Buruli ulcer caused by M. ulcerans disease were randomly assigned to one of two groups. In one group, two creams containing sodium nitrite (6%, wt/wt) or citric acid monohydrate (9%, wt/wt) were applied daily for 6 weeks, while the other group received a placebo. In the second 6 weeks, both groups received the nitrogen oxide-generating combination of creams. Treatment was continued for another 4 weeks for patients whose ulcers were not healed after 12 weeks. The ulcer surface area was monitored by weekly tracings made by assessors blinded to the treatment. In the first 6 weeks, patients on sodium nitrite and citric acid monohydrate (group I, active treatment) showed a rapid decrease in ulcer size from 28.6 +/- 5.6 cm2 (mean +/- standard error) to 12.6 +/- 3.2 cm2, a decrease significantly greater than that in group II (from 15.3 +/- 3.1 to 11.7 +/- 3.7 cm2; P = 0.03). Five ulcers in the placebo group enlarged during this period, compared with one in the active group. In the second 6 weeks (both groups on active treatment), the rates of healing were similar for the two groups and there was a significant reduction in ulcer size in group II (previously on placebo) compared to the first 6 weeks. Yellow pigmentation of the skin, which disappeared 3 days after treatment was stopped, was the only side effect to date. We conclude that creams releasing nitrogen oxides increase the healing rate of ulcers caused by M. ulcerans infection with minimal adverse events. This is the first controlled trial of any form of therapy which demonstrates efficacy in treating this disease.

The ingestion of inorganic nitrate increases gastric S-nitrosothiol levels and inhibits platelet function in humans

Platelets play an important role in the development of vascular disease, while vegetarian diets, which are rich in inorganic nitrate, protect against it. This study was performed to assess the effect of potassium nitrate (KNO(3)) ingestion on platelet function in humans. Oral KNO(3) (2 mmol) was given to healthy volunteers and its effect on platelet function assessed by measuring the aggregant effect of collagen. Blood samples were taken for measurement of plasma S-nitrosothiols (RSNO) and platelet cyclic GMP and nitrotyrosine levels. Gastric juice samples were taken for measurement of RSNO. In a separate study, the effect of oral KNO(3) on portal RSNO levels in patients with intrahepatic porto-systemic shunts was assessed. KNO(3) caused a significant increase in gastric RSNO levels, from 0.46 +/- 0.06 to 3.62 +/- 2.82 microM (t(max) 45 min; P < 0.001), and significantly inhibited platelet function (t(max) 60 min; P < 0.001). There was no effect on systemic or portal RSNO, platelet cGMP or platelet nitrotyrosine levels. Oral KNO(3) inhibits platelet aggregation. The time course suggests that gastric RSNO production may be involved in this effect. The protection against vascular events associated with a high intake of vegetables may be due to their high nitrate content.

Study of a combined percutaneous local anaesthetic and nitric oxide-generating system for venepuncture

Nitric oxide (NO) may be generated and delivered into the skin via a novel system of sodium nitrite and ascorbic acid. This placebo-controlled, double-blind trial compared the analgesic properties of this system alone and when supplemented with lidocaine. The pain of dorsal hand vein cannulation was assessed in 100 volunteers. The NO-generating system was prepared by mixing two gels, the first KY jelly and sodium nitrite (10% w/v), the second KY jelly and ascorbic acid (10% w/v). NO-generating gel was the placebo treatment, and when combined with lidocaine (final concentration 5%), formed the active treatment. The gels were applied to the dorsum of the hands bilaterally and simultaneously for 10 min. Following cannulation, pain perception was measured with a verbal rating score (VRS) and a visual analogue score (VAS). The active formulation significantly decreased the VRS (p < 0.0001) and also reduced the mean VAS by > 40% compared with placebo (p < 0.001). This investigation suggests a 10-min topical application of anaesthetic combined with the NO-generation system may provide effective analgesia for venous cannulation in adults.

Potential therapeutic uses for S-nitrosothiols

The S-nitrosothiols (RSNOs) are thought to represent a circulating endogenous reservoir of nitric oxide (NO), and may have potential as donors of NO, distinct from currently used agents. They have the general formula RSNO, and naturally occurring examples include S-nitrosocysteine, S-nitrosoglutathione and S-nitrosoalbumin, in which R is an amino acid, polypeptide and protein respectively. RSNOs have anti-platelet properties, a theoretical role in the treatment of asthma and the potential to be used as agents to treat infectious diseases ranging from the common cold to AIDS. RSNOs are relatively unstable, being degraded to release NO and the corresponding disulphide. Their stability is influenced by the properties of the R group, heat, light, the presence of transition metal ions (in particular copper) and the presence of other thiols. RSNOs participate in transnitrosation reactions in which the -NO group is transferred to another thiol to form a more stable RSNO. Thus the stability of RSNOs in vivo is difficult to predict, and this has led to the development of more stable analogues, in which the properties of R are modified. Potential interactions of RSNOs include that with ascorbic acid (vitamin C), which enhances the ability of copper to catalyse their degradation. Transnitrosation reactions with thiol-containing enzymes can influence protein function, and the intracellular thiol glutathione, levels of which are influenced by many disease states, can also influence stability. Thus, although RSNOs have many theoretically useful properties, there are also many aspects of their biochemistry that need to be addressed before their therapeutic potential can be fully realized.

Antimicrobial effect of acidified nitrite on periodontal bacteria

The antimicrobial agent nitric oxide (NO) is formed in the mouth and its concentration is directly related to salivary nitrite, which in turn is related to dietary nitrate intake. The aim of this study was to determine whether nitrite under acidic conditions will have an inhibitory effect, possibly occurring through NO production, on the periodontal disease pathogens Fusobacterium nucleatum, Eikenella corrodens and Porphyromonas gingivalis. Whereas the growth of these organisms was inhibited by a more acid pH, the addition of nitrite caused a marked, further dose-dependent reduction in bacterial numbers after exposure. The ability of these bacteria to recover from nitrite exposure was also affected by pH and nitrite concentration. At acidity levels below pH 5.0, low concentrations of nitrite (0.2 mM) caused effective complete killing of the periodontal bacteria. Addition of sodium thiocyanate did not increase the bacteriostatic or bacteriocidal activity of acidified nitrite against any of the 3 bacteria. These results demonstrate the possibility that nitrite in saliva, under appropriate conditions, may have an effect on the growth and survival of the bacteria implicated in periodontal disease.

A novel method for the delivery of nitric oxide therapy to the skin of human subjects using a semi-permeable membrane

Nitric oxide (NO) is a mediator of essential biological processes, including vasodilatation, anti-microbial activity and wound healing. A chemical system using sodium nitrite and ascorbic acid has been developed which generates significant amounts of NO. The originally described system was messy and impractical, and the high acidity may cause pain and further tissue damage in ulcerated skin. To overcome this, a selectively permeable, hydrophilic polyester co-polymer membrane system (Sympatex ) has been identified that can be placed between the NO-generating chemicals and the skin. The aim of the present study was to determine whether NO derived from this chemical system was able to diffuse through the membrane and have a measurable vasodilatory effect on forearm skin in healthy volunteers. The Sympatex 10 microm membrane was found to be highly permeable to NO, while preventing passage of the constituents of the NO-generation gel to the skin. The transmembrane NO-generation system had a vasodilatory effect comparable with that resulting from direct topical application. Additionally, the NO generated was effective in killing Staphylococcus aureus and Escherichia coli at doses lower than those required to increase skin blood flow. The vasodilatory and anti-microbial effects of this system may be useful as a patch-based topical therapy for skin ulceration, particularly when there is concomitant ischaemia and infection.

Plasma nitrate concentrations in children with infectious and noninfectious diarrhea

BACKGROUND

In patients with intact renal function and low dietary nitrate intake, plasma nitrate concentrations reflect endogenous nitric oxide production and are shown to be increased during inflammatory processes. The aim of this study was to compare plasma nitrate concentrations and hence endogenous nitric oxide production in children with infectious and noninfectious diarrhea and to determine whether plasma nitrate concentrations could serve as a discriminant test between acute and chronic diarrhea in children.

METHODS

Three groups of patients were identified: 14 patients with acute gastroenteritis, 13 patients with chronic noninfectious diarrhea, and 14 patients with no evidence of gastrointestinal pathology and no underlying infectious process, who served as control subjects. Plasma nitrate concentrations were determined spectrophotometrically using the Greiss reaction before reduction to nitrite with a copper-coated cadmium column.

RESULTS

Mean plasma nitrate concentrations were 405.3 micromol/L +/- 281.6 micromol/L (standard deviation) in patients with infectious diarrhea, 134.7 micromol/L +/- 77.0 micromol/L in patients with chronic diarrhea, and 54.1 micromol/L +/- 20.1 micromol/L in control subjects (F = 42.6, P < 0.0001; analysis of variance). Plasma nitrate concentrations were significantly higher in the infectious diarrhea group compared with the noninfectious diarrhea and control groups (Student-Newman-Keuls test, P < 0.5).

CONCLUSIONS

Although an optimal cutoff concentration cannot be defined, plasma nitrate concentrations in excess of 300 micromol/L are suggestive of an infectious process whereas values less than 100 micromol/L are indicative of noninfectious diarrhea.

Antimicrobial effect of acidified nitrite on dermatophyte fungi, Candida and bacterial skin pathogens

AIMS

Nitric oxide is generated from sweat nitrite in the acidic environment of the skin surface and is thought to contribute to protection against infection. This study examined the sensitivity of Trichophyton mentagrophytes, T. rubrum, Candida albicans, Streptococcus pyogenes, Staphylococcus aureus and Propionibacterium acnes to acidified nitrite.

METHODS AND RESULTS

Organisms were cultured in varying concentrations of nitrite and pH for different lengths of time, before being transferred to recovery medium. With the exception of Strep. pyogenes, addition of nitrite increased the antimicrobial activity of acid solutions against all organisms tested. The rank order of sensitivity was: C. albicans < T. rubrum < T. mentagrophytes < Staph. aureus < P. acnes, with P. acnes being most sensitive.

CONCLUSION

This work has shown that acidified nitrite is microbiocidal to common cutaneous pathogens. The concentrations of nitrite required to kill pathogenic fungi and bacteria in in vitro assays were higher than the concentrations of nitrite measured in sweat. However, additional co-factors in vivo and in sweat may potentiate the effect of acidified nitrite.

SIGNIFICANCE AND IMPACT OF THE STUDY

Pharmacological preparations of acidified nitrite are novel antimicrobial agents. These data suggest skin organisms which may be sensitive to this treatment.

Is random screening of value in detecting glucocorticoid-remediable aldosteronism within a hypertensive population?

INTRODUCTION

Glucocorticoid-remediable aldosteronism (GRA) is a rare inherited cause for hypertension associated with a significant morbidity and mortality at an early age. Individuals with this abnormality frequently present with severe hypertension which is resistant to standard antihypertensive therapy, a strong family history of hypertension, intracranial haemorrhage, and sporadic hypokalaemia. However many affected individuals may appear phenotypically indistinguishable from normal essential hypertensives but remain at high risk of morbidity and mortality.

OBJECTIVE

To determine how effective random or targeted screening of hypertensive patients is for the detection of GRA.

DESIGN

A prospective study involving the screening of 300 hypertensive patients chosen at random attending the Aberdeen Hypertension Clinic and, during the same period, the targeted screening of patients with a medical and family history suggestive of GRA.

SETTING

A University hospital with a primary catchment of 500,000 inhabitants and a hypertension clinic population of over 8500 patients.

RESULTS

Random screening failed to identify any GRA mutation-positive individuals. Targeted screening of selected individuals revealed two index families and four further families containing 40 mutation-positive individuals.

CONCLUSION

Targeted screening of hypertensive individuals with a family history of hypertension, cerebral haemorrhage, a history of hypertension from an early age, resistant hypertension which has proven difficult to control and hypokalaemia revealed two index cases and four further individuals and 30 hypertensive and 10 normotensive members of their families with GRA.

A topical nitric oxide-generating therapy for cutaneous leishmaniasis

Nitric oxide (NO) synthesized by macrophages is cidal to Leishmania. Since NO diffuses into tissues, we reasoned that NO-generating creams applied topically to lesions might be an effective and inexpensive treatment for cutaneous leishmaniasis (CL). NO was generated non-enzymatically by the acidification of nitrite (KNO2) by ascorbic acid (ASC) or salicylic acid (SAL). Experiments in vitro showed that the combinations of KNO2 and SAL, ASC, or KC1 all killed promastigotes and amastigotes of L. major in a dose- and time-dependent manner, but were toxic to macrophages at higher concentrations. Experiments in vivo showed modest efficacy of the combinations applied topically to L. major CL lesions of BALB/c mice. Forty patients with parasitologically proven L. tropica CL from Aleppo, Syria, were treated for 4 weeks with KNO2 in aqueous cream combined with KC1, ASC, or SAL. Only 11 (28%) of 40 patients showed improvement and only 5 (12%) of 40 were cured at 2 months. Further development of NO-generating creams is warranted.

Nitric oxide synthesis and isoprostane production in subjects with type 1 diabetes and normal urinary albumin excretion

The role of nitric oxide (NO) and free radicals in the development of microvascular disease in type 1 diabetes remains unclear. We have measured NO and isoprostane (a stable marker of in vivo lipid peroxidation) production in 13 type 1 diabetic subjects with normal urinary albumin excretion and 13 healthy volunteers. Whole-body NO synthesis was quantified by measuring the urinary excretion of 15N-nitrate after the intravenous administration of L-[15N]2-arginine. The urinary excretion of the major urinary metabolite of 15-F2t-isoprostane (8-iso-prostaglandin-F2alpha), 2,3-dinor-5,6-dihydro-F2t-IsoP, was quantified as a marker of in vivo lipid peroxidation. Whole-body NO synthesis was significantly higher in diabetic subjects compared with control subjects (342 vs. 216 nmol 15N-nitrate/mmol creatinine [95% CI of the difference 45-207], P = 0.005). This increase was not explained by a difference in renal function between the 2 groups. There was no difference in 2,3-dinor-5,6-dihydro-F2t-IsoP excretion between diabetic subjects and control subjects (44.8+/-7.8 vs. 41.4+/-10.0 ng/mmol creatinine, mean +/- 95% CI). However, there was an inverse correlation between NO synthesis and free radical activity in subjects with diabetes (r = -0.62, P = 0.012) that was not observed in control subjects (r = 0.37, P = 0.107). We conclude that whole-body NO synthesis is higher in type 1 diabetic subjects with normal urinary albumin excretion than in control subjects. The inverse correlation between isoprostane production and NO synthesis in diabetic subjects is consistent with the hypothesis that NO is being inactivated by reactive oxygen species.

Inhibition of platelet aggregation with glyceryl trinitrate and xanthine oxidoreductase

Xanthine oxidoreductase (XOR) is a mammalian enzyme that possesses a series of redox centers, which use either NAD(+) or molecular oxygen for oxidation of the purines xanthine and hypoxanthine to uric acid. The ability of XOR to act as an NADH oxidase is a less well recognized function of the enzyme, and it is this function that we used to explore the metabolism of glyceryl trinitrate. The antiplatelet effect of nitric oxide (NO) on platelet aggregation was used as a bioassay to assess the bioconversion of glyceryl trinitrate to NO by XOR. The thromboxane mimetic U46619, 2 microM, was used to stimulate platelet aggregation in platelet-rich plasma prepared from healthy drug-free human volunteers. All incubations were carried out at 37 degrees C for 2 min after the addition of U46619. XOR produced a dose-dependent antiaggregant effect when incubated with glyceryl trinitrate (GTN), 220 microM. This did not occur when GTN or XOR was incubated with platelet-rich plasma independently. The antiaggregant effect of XOR plus GTN was dose dependently inhibited by allopurinol, with an IC(50) of 100 microM. The addition of superoxide dismutase (SOD), 100 U/ml produced a shift to the left in the antiaggregant dose-response curve for XOR. The IC(50) for XOR at 200 U/l without SOD was decreased to 80 U/l with SOD. Oxyhemoglobin, an extracellular NO scavenger, produced a dose-dependent, noncompetitive inhibition of the antiaggregant effect of XOR plus GTN. These findings suggest that GTN may be reduced to NO in vitro by the enzyme XOR in sufficient amounts to inhibit platelet aggregation.

Molluscum contagiosum effectively treated with a topical acidified nitrite, nitric oxide liberating cream

A double-blind, group-sequential clinical trial of acidified nitrite was performed to demonstrate the efficacy of this nitric oxide donor in treating molluscum contagiosum. Subjects received either 5% sodium nitrite co-applied with 5% salicylic acid under occlusion, or identical cream with 5% salicylic acid, omitting sodium nitrite. Active and control treatment groups were well matched for the number and duration of lesions and made a similar number of applications. We found a 75% cure rate in the active treatment group and 21% cure with control treatment (P = 0.01). The mean time to cure was 1.83 months. Staining of the skin and irritation were frequent side-effects but did not prevent successful treatment.

Antimicrobial effect of acidified nitrite on cariogenic bacteria

The antimicrobial agent nitric oxide (NO) is formed in the mouth and its concentration is directly related to salivary nitrite, which in turn is related to dietary nitrate intake. The aim of this study was to determine whether nitrite under acidic conditions will have an inhibitory effect, possibly occurring through NO production, on Streptococcus mutans, Lactobacillus casei and Actinomyces naeslundii. Whereas the growth of S. mutans was inhibited by a more acid pH, the addition of nitrite caused a marked, further dose-dependent reduction in bacterial numbers after 24 h of exposure. Similar effects were observed with A. naeslundii and L. casei. The ability of these bacteria to recover from nitrite exposure was also markedly affected by nitrite concentration. At acidity levels below pH 7, low concentrations of nitrite (0.2 mM) caused effective complete killing of S. mutans, with similar effects on the other organisms tested. These results demonstrate the possibility that nitrite in saliva has an effect on the growth and survival of cariogenic bacteria.