Dental standards: fifty years of development.

Dental standards play a vital and important role in society by contributing to the quality and safety levels of products used in dental treatments by dental professionals as well as the hygiene products used by the general public. Few members of the public or indeed many dentists fully appreciate the contribution made by ISO international dental standards to the safety and quality of dental care. Further more the United Kingdom played a significant role in the establishment of the international standards organisation (ISO). The first two meetings of the dental international standards committee took place in England. In this article Derek W. Jones outlines the significant and important role played by the UK during the fifty years of dental international standards.

Effect of soy and milk protein supplementation on serum lipid levels: a randomized controlled trial.

BACKGROUND/OBJECTIVE: Previous clinical trials have documented that soy protein reduces low-density lipoprotein cholesterol and increases high-density lipoprotein (HDL) cholesterol compared with milk protein. However, the effect of soy protein on lipids compared with carbohydrate has not been not well studied. We examined the effect of soy and milk protein supplementation on lipids and lipoproteins compared with carbohydrate among adults without hypercholesterolemia. SUBJECTS/METHODS: We conducted a randomized, double-blind, 3-phase crossover trial among 352 US adults with serum total cholesterol level of <240 mg/dl from September 2003 to April 2008. Trial participants were assigned to 40 g/day supplementation of soy protein, milk protein or complex carbohydrate from wheat each for 8 weeks in random order with a 3-week washout period between interventions. Overnight fasting blood samples were collected at the termination of each intervention phase. RESULTS: Compared with carbohydrate, soy protein supplementation was significantly associated with a net change (95% confidence interval (CI)) in total cholesterol and total/HDL cholesterol ratio of -3.97 mg/dl (-7.63 to -0.31, P=0.03) and -0.12 (-0.23 to -0.01, P=0.03), respectively. Compared with milk protein, soy protein supplementation was significantly associated with a net change (95% CI) in HDL and total/HDL cholesterol ratio of 1.54 mg/dl (0.63 to 2.44, P=0.0009) and -0.14 (-0.22 to -0.05, P=0.001), respectively. Compared with carbohydrate, milk protein supplementation was significantly associated with a net change (95% CI) in HDL of -1.13 mg/dl (-2.05 to -0.22, P=0.02). CONCLUSIONS: This randomized controlled trial indicates that soy protein, but not milk protein, supplementation improves the lipid profile among healthy individuals.

A strength-endurance index for power grip.

INTRODUCTION: The purpose of this study was to quantify muscle strength and endurance in power grip. METHOD: Workers (74 M and 74 F, 18-72 years) squeezed a dynamometer for a 60 s, 18-cycle test. Initial strength (IS) and final strength (FS) were calculated as the mean peak force for cycles 1-3 and 16-18, respectively. Endurance was defined by the strength decrement index (SDI) where SDI = (IS - FS)/IS x 100. A grip strength-endurance analyzer was constructed from IS and SDI data which were depicted on two parallel, linearly scaled axes. Discrete IS and SDI scores were connected on each axis with a vector. The vector (Vmag) was measured directly from the analyzer and its direction identified from its slope. Integer scales transformed discrete IS and SDI scores into individual strength-endurance performance scores (SEPS). RESULTS: Better than 95% of the sample (n > or = 141) scored within acceptable test ranges defined as the combined sample mean +/- 2SD, for SDI, Vmag and SEPS. Vmag was the best predictor for SEPS. Linear regression for SEPS was SEPS (combined) = 0.09 (Vmag) - 0.29: (SEE = 0.829). The analyzer revealed individual scores outside acceptable ranges for injured and uninjured efforts. CONCLUSION: The development of a power grip strength-endurance analyzer provided a simple method to graph individual power grip performances. Converting strength and endurance scores to integers and summing them (SEPS) provided a simple means to represent individual estimates of power grip strength-endurance performance.

A Scandinavian tragedy.

This paper briefly reviews the logic surrounding the controversial banning of dental amalgam by the Norwegian government. The very small contribution from dentistry to environmental mercury pollution and the significant advantages of amalgam as a dental restorative are emphasised.

Development of explicit criteria to measure adherence to hypertension guidelines.

Measures of adherence to hypertension guidelines have historically been based on prescription data or physician survey data regarding treatment practices. These methods have limitations that decrease their accuracy. As part of a randomized controlled study testing the effects of pharmacist/physician collaboration on adherence to hypertension guidelines, the investigators and an expert panel developed a JNC 7 measurement tool. The final guideline adherence measurement tool includes 22 explicit criteria in four domains of care. An exploratory factor analysis, conducted to assess the structure of the tool, suggests three underlying treatment dimensions in hypertension care. The adherence measurement tool will allow researchers to link specific elements of care to improved blood pressure control. In addition, use of the tool will provide clinicians with a taxonomy for evaluating practice and describing the effect of improved patient care on patient outcomes.

Urokinase induced fibrinolysis in thromboelastography: a model for studying fibrinolysis and coagulation in whole blood.

BACKGROUND: The contact system (CS) proteins, factor XII and prekallikrein are thought to have roles in blood coagulation and fibrinolysis. Recent research has suggested that the CS proteins might be more important in fibrinolysis and cell function than in coagulation. Most studies on fibrinolysis have used plasma or euglobulin assays, ignoring the influence of cellular elements of blood on the fibrinolytic process. OBJECTIVE AND METHODS: In order to study both coagulation and fibrinolysis in whole blood (WB), we have developed a thromboelastography (TEG) assay to investigate both coagulation and fibrinolysis in the same blood sample. In this assay, named urokinase (UK) induced fibrinolysis in thromboelastography (UKIFTEG), TEG is performed on recalcified citrated WB in the presence of UK. Large variations in Ly60 (percentage lysis 60 min after clot formation) were obtained between different donors with the same UK concentration. The UKIFTEG assay was therefore performed using UK concentrations that gave Ly60 values in the approximate range of 20-40%. RESULTS: The effect of CS activation was investigated in the presence or absence of celite (10 mg mL(-1) blood). Celite shortened the clotting time (CT), and increased Ly60 values. Factor XIIa (FXIIa) and plasma kallikrein (KK) produced concentration dependent reductions in CT (significant at concentrations of 1303 and 2600 ng mL(-1) blood, respectively) and increased Ly60 values (significant at concentrations of 652 and 1300 ng mL(-1) blood, respectively). CONCLUSIONS: Our results show that CS activation and both FXIIa and KK produce reductions in clotting time and enhanced fibrinolysis in UKIFTEG.

Cardiovascular disease risk factors in habitual exercisers, lean sedentary men and abdominally obese sedentary men.

OBJECTIVE: To investigate whether the favourable cardiovascular disease (CVD) risk factor profile of habitual exercisers is attributable to exercise or leanness. DESIGN: Cross-sectional study of 113 nonsmoking men aged 30-45 y. CVD risk factors were compared in exercisers (n=39) and sedentary men (n=74), and in subgroups of lean exercisers (n=37), lean sedentary men (n=46) and obese sedentary men (n=28). Waist girth was used to identify lean (<100 cm) and abdominally obese (> or =100 cm) subgroups. MEASUREMENTS: Blood pressure, physical activity (7-day recall), physical fitness (maximum oxygen consumption) and fasted lipoproteins, apolipoprotein (apo) B, triglycerides, glucose and fibrinogen. RESULTS: Exercisers were fitter and leaner than sedentary men and had a better CVD risk factor profile. Total cholesterol, LDL-cholesterol and apo B concentrations were lower in lean exercisers than in lean sedentary men, suggesting that exercise influences these risk factors. Indeed, time spent in vigorous activity was the only significant predictor of total cholesterol and LDL-cholesterol in multiple linear regression models. Exercise status had little influence on triglycerides and HDL-cholesterol (HDL-C), and unfavourable levels were only evident among obese sedentary men. Waist girth was the sole predictor of triglycerides and HDL-C, explaining 44 and 31% of the variance, respectively. CONCLUSIONS: These findings suggest that the CVD risk factor profile of habitual exercisers is attributable to leanness and exercise. Leanness is associated with favourable levels of HDL-C and triglycerides, while exercise is associated with lower levels of total cholesterol, LDL-cholesterol and apo B.

The antigenic binding site(s) of antibodies to factor XII associated with the antiphospholipid syndrome.

Phospholipid binding proteins, including factor XII (FXII), are known to be targeted by antiphospholipid antibodies (aPA). Factor XII antibodies (FXIIab) have been described in some patients with the antiphospholipid syndrome (APS) and have been shown to lead to reduced levels of FXII. The antigenic binding site(s) and the pathophysiological effects of FXIIab are unknown. In an attempt to elucidate the binding site of these antibodies, immobilized plasma kallikrein was used to cleave FXII into its 52-kDa heavy-chain (HCFXII) and 28-kDa light-chain (LCFXII) components. Plasma samples from 12 female patients with definite APS and FXIIab were investigated for the presence of antibodies to FXII, HCFXII and LCFXII. All but one patient's plasma reacted to FXII, HCFXII and LCFXII in a similar manner. One patient gave markedly reduced positivity to HCFXII and LCFXII, suggesting that the FXIIab in this patient had a higher affinity for the intact FXII molecule. To further investigate the antigenic binding site(s) of FXII, 150 biotinylated peptides of the known FXII sequence were synthesized using a Multipin(TM) peptide synthesis procedure. The IgG and IgM fractions of the 12 patients' plasma were purified by affinity chromatography. The synthesized peptides were captured on streptavidin plates and individual patients' purified FXIIab assayed against the peptides in a modified enzyme-linked immunosorbent assay (ELISA). Two regions were identified as possible antigenic binding site(s) for FXIIab: one in the growth factor domain and the other in the catalytic domain.

Putting dental mercury pollution into perspective.

This paper deals with the issue of amalgam waste from dental offices. The aim is to put into perspective the very small contribution of dental mercury to the overall volume of mercury discharged into the environment each year. While the amount discharged from dental offices is very small compared to other sources, the amount discharged into the environment from amalgam fillings in people's mouths is estimated as less than 2% of the amount from dental offices. At least 50% of mercury in the environment comes from natural sources. The major source of man-made mercury pollution is the industrial burning of fossil fuels. It is important to distinguish between inorganic mercury and organic mercury in terms of the impact on the health of the population.

Depletion and restoration of endogenous monoamines affects beta-CIT binding to serotonin but not dopamine transporters in non-human primates.

The radioligand [123I]beta-CIT binds to dopamine transporters in striatum and to serotonin transporters in brainstem. Endogenous dopamine or serotonin may compete with radioligand binding at monoamine transporters. We used alpha-methyl-p-tyrosine (AMPT) to block dopamine production and measured [123I]beta-CIT binding before and after endogenous dopamine was restored by IV administration of the dopamine precursor L-dihydroxyphenylalanine (L-DOPA) in rhesus monkeys. P-chlorophenylalanine (pCPA) was used to inhibit serotonin production, and [123I]beta-CIT binding was assessed before and after IV administration of the serotonin precursor 5-hydroxy-L-tryptophan (L-5-HTP) restored endogenous serotonin. Pretreatment with benserazide blocked peripheral decarboxylization in both paradigms. Serotonin restoration measurably displaced [123I]beta-CIT binding to brainstem serotonin transporters but not to striatal dopamine transporters. Restoration of dopamine apparently did not affect [123I] beta-CIT binding to striatal dopamine transporters. However, dopamine restoration reduced radioligand binding to brainstem serotonin transporters, most likely due to dopamine release from serotonin neurons following L-DOPA administration. The higher striatal density of dopamine transporters relative to dopamine concentrations may explain why [123I] beta-CIT displacement by endogenous dopamine was not observed. This study indicates that [123I]beta-CIT binding in brainstem (raphe area) is affected by endogenous serotonin release in vivo and that L-DOPA treatment may cause serotonin neurons in the brainstem to corelease dopamine.

Mechanical properties of commercial high strength ceramic core materials.

OBJECTIVE: The objective of the present study is to evaluate and compare the flexural strength, dynamic elastic moduli and true hardness (H(o)) values of commercial Vita In-Ceram alumina core and Vita In-Ceram matrix glass with the standard aluminous porcelain (Hi-Ceram and Vitadur), Vitadur N and Dicor glass and glass-ceramic. METHODS: The flexural strength was evaluated (n=5) using 3-point loading and a servo hydraulic Instron testing machine at a cross head speed of 0.5 mm/min. The density of the specimens (n=3) was measured by means of the water displacement technique. Dynamic Young's shear and bulk moduli and Poisson's ratio (n=3) were measured using a non-destructive ultrasonic technique using 10 MHz lithium niobate crystals. The true hardness (n=3) was measured using a Knoop indenter and the fracture toughness (n=3) was determined using a Vickers indenter and a Tukon hardness tester. Statistical analysis of the data was conducted using ANOVA and a Student-Newman-Keuls (SNK) rank order multiple comparative test. RESULTS: The SNK rank order test analysis of the mean flexural strength was able to separate five commercial core materials into three significant groups at p=0.05. Vita In-Ceram alumina and IPS Empress 2 exhibited significantly higher flexural strength than aluminous porcelains and IPS Empress at p=0.05. The dynamic elastic moduli and true hardness of Vita In-Ceram alumina core were significantly higher than the rest of the commercial ceramic core materials at p=0.05. SIGNIFICANCE: The ultrasonic test method is a valuable mechanical characterization tool and was able to statistically discriminate between the chemical and structural differences within dental ceramic materials. Significant correlation was obtained between the dynamic Young's modulus and true hardness, p=0.05.

Serotonin transporter availability correlates with alcohol intake in non-human primates.

A low level of alcohol intoxication upon initial exposure and impulsive aggressiveness predispose humans to alcoholism. In non-human primates, central serotonin transporter availability and turnover rate were associated with aggressive behavior and a low response to initial alcohol exposure. We assessed the respective effects of these factors on alcohol intake in a free choice paradigm. Serotonin transporter availability in the raphe area, the origin of central serotonergic projections, was measured with single-photon emission computed tomography and the radioligand [(123)I]beta-CIT in 11 rhesus monkeys with low and high central serotonin turnover. The amount of alcohol intake in the 3-month observation period was positively correlated with serotonin transporter availability (R=0.76, P=0.006), but not with aggressiveness (R=0.19, P=0.6) or alcohol response upon first exposure (R=-0.48, P=0.2). In a linear multiple regression analysis with serotonin transporter availability, alcohol response, and aggressiveness as independent variables, 82% of the variance of alcohol intake was explained and serotonin transporter availability emerged as the only statistically significant factor (beta=7.81, P=0.006). These observations indicate that there may be a direct relationship between serotonin transporter availability and alcohol intake after controlling for aggression and alcohol response on first exposure.

Relationship between cortisol and serotonin metabolites and transporters in alcoholism [correction of alcolholism].

BACKGROUND: Stress hormone activation may induce clinical depression via an interference with central serotonergic neurotransmission. In alcoholics, a reduction in serotonin transporters was associated with clinical depression, and an activation of cortisol secretion is frequently found during detoxification. We assessed the interaction between stress hormone activation, serotonin transporters, monoamine metabolites in the cerebrospinal fluid (CSF), and mood states in male and female alcoholics and healthy control subjects. METHODS: The availability of serotonin transporters was measured with [I-123]beta-CIT and SPECT in the raphe area of the brainstem in 31 alcoholics after four weeks of abstinence and in 25 age-matched healthy volunteers. Concentrations of plasma cortisol were measured on the day of the SPECT scan. Within one week after the SPECT scan, we assessed monoamine metabolites and corticotropin-releasing factor (CRF) in the CSF. RESULTS: Clinical depression was associated with a reduction in serotonin transporter availability among male alcoholics. Among male alcoholics and healthy volunteers, CSF 5-HIAA and plasma cortisol concentrations were inversely correlated with the availability of raphe serotonin transporters and positively correlated with the severity of clinical depression. No significant correlations were observed between raphe serotonin transporters and HVA, MHPG and CRF concentrations in the CSF. CONCLUSION: Our findings support the hypothesis of an interaction between reduced serotonin transporters, stress hormone activation and clinical depression. They confirm the hypothesis that serotonergic neurotransmission dysfunction in alcoholism is limited to male alcoholics. The observed interactions between high cortisol concentrations and reduced serotonin transporter availability warrant further studies in major depression and other neuropsychiatric diseases with implied cortisol activation and serotonergic dysfunction.

Changes in high molecular weight kininogen levels during and after cardiopulmonary bypass surgery measured using a chromogenic peptide substrate assay.

High molecular weight kininogen (HK) is a co-factor in the blood-contact activation system. A chromogenic peptide substrate assay for HK (HKcs) has been developed in which test plasmas are mixed with diluted HK-deficient plasma and incubated with a soluble contact system activator that activates prekallikrein and factor XII. Calcium chloride, a synthetic thrombin inhibitor and a chromogenic peptide substrate for activated factor X (FXa) are then added. The FXa generated cleaves the FXa substrate releasing p-nitroanaline, which is measured photometrically. Test plasma HK values were calculated from a standard curve generated using a pooled normal plasma. Acceptable intra-assay and inter-assay precision values were obtained and levels of HK up to 200% were measurable. The assay measured HK in plasmas deficient in factor XII, prekallikrein and factor XI, was not affected by antiphospholipid antibodies and gave an acceptable correlation (r = 0.95) when normal plasmas and mixtures of HK-deficient and normal pooled plasma, calculated to give HK levels of 25 and 50%, were compared using HKcs and a HK one-stage clotting assay. The HKcs was used to measure HK levels in seven patients undergoing cardiopulmonary bypass (CPB). HK levels fell significantly during CPB (P = 0.0014) and were significantly higher (P = 0.016) 6 days after CPB, suggesting that HK may be a positive acute-phase reacting protein.

Therapeutic considerations in the treatment of obesity hypertension.

Obesity, now recognized as an independent risk factor for cardiovascular disease, is closely associated with hypertension. Complex mechanisms link increasing body weight with increasing blood pressure. Treatment of the obese patient with hypertension requires consideration of physiologic changes related to obesity hypertension. Lifestyle modification, including weight reduction and increased physical activity, can directly influence blood pressure levels and improve blood pressure control in obese, hypertensive patients. Clinical trials are needed to determine the most effective antihypertensive drugs for the obese, hypertensive patient. Antiobesity drugs offer viable adjunctive pharmacotherapy for obesity hypertension, but additional long-term studies are needed to support their safety and efficacy.

Associations between weight gain and incident hypertension in a bi-ethnic cohort: the Atherosclerosis Risk in Communities Study.

OBJECTIVE: To examine associations between weight gain and changes in blood pressure and the incidence of hypertension in four ethnicity-gender groups. DESIGN: Longitudinal closed cohort studied over an average of 6 y. SUBJECTS: Total of 9309 white and African-American men and women 45-64 y of age who participated in the Atherosclerosis Risk in Communities (ARIC) Study. METHODS: Weight and blood pressure were measured at baseline and after an average of 3 and 6 y of follow-up. Proportional hazard models with weight gain as a time-dependent variable were used to examine the association between weight gain and changes in blood pressure and hypertension. Multivariate models were used with baseline SBP, DBP, age, BMI, height, WHR, smoking, physical activity, education, caloric intake, fat intake and study center as covariates. RESULTS: Weight gain was associated with increases in SBP and DBP in all groups. Hazard ratios for hypertension associated with 1 kg annual weight gain were 1.36 (95% CI, 1.29, 1.45) in white women, 1.12 (95% CI, 1.03, 1.21) in African-American women, 1.35 (95% CI, 1.27, 1.43) in white men and 1.43 (95% CI, 1.27,1.61) in African-American men. CONCLUSION: Weight gain was associated with increased blood pressure and increased incidence of hypertension. The association was weaker among African-American women compared to other ethnicity-gender groups.

Ankle-brachial index and 7-year ischemic stroke incidence: the ARIC study.

BACKGROUND AND PURPOSE: Low ankle-brachial index (ABI), which is the ratio of tibial artery systolic blood pressure to brachial systolic artery pressure, is known to be a measure of lower limb peripheral artery disease as well as a marker for other cardiovascular disease events. The ability of ABI to predict incident ischemic stroke, however, is not established in population-based studies. METHODS: ABI was measured in a cohort of 14 839 black and white men and women aged 45 to 64 years. Stroke incidence was calculated during approximately 7 years of follow-up. RESULTS: A total of 206 incident strokes occurred. Adjusted stroke incidence rates were markedly higher for those in the lowest versus the highest categories of ABI for men, women, blacks, and whites. The proportional hazards regression model, adjusted for age, race, gender, and field center, showed an inverse linear trend between ABI and ischemic stroke incidence (P<0.0001). The lowest group (ABI <0.80) had a hazard ratio of 5.68 (95% CI 2.77 to 11.66). After adjustment for major risk factors in a multivariate model, the hazard ratio in the lowest group was elevated (1.93) but no longer statistically significant (95% CI 0.78 to 4.78). There was, however, still an indication of an overall inverse linear trend between ABI and incident stroke (P=0.03). CONCLUSIONS: Low ABI was strongly associated with increased incidence of ischemic stroke, but the relationship was substantially reduced after adjustment for major cardiovascular risk factors.