Impact of Immediate and Delayed Photo-activation of Self-adhesive Resin Cements on Bonding Efficacy and Water Uptake Under Simulated Pulpal Pressure.

This study investigated the effect of immediate versus delayed photo-activation on the bonding performance and water uptake of self-adhesive (SA) resin cements under simulated pulpal pressure (SPP). The occlusal dentin surface was exposed in 66 extracted third molars. Resin composite cylinders were cemented to dentin under SPP, with either RelyX Unicem 2 (RU) (3M Oral Care, St Paul, MN, USA) or Maxcem Elite (MC) (Kerr, Orange, CA, USA). Each cement group was equally divided into three groups (n=8 each) according to the time elapsed between placement and photo-activation: immediate activation (IM), 30-second delayed activation (D30), or 120-second delayed activation (D120). Shear bond strength (SBS) was measured, and the type of failure was determined using a stereomicroscope. Three additional samples from each experimental subgroup were used for confocal laser scanning microscopy (CLSM) analysis. A fluorescent dye solution was added to the pulpal fluid reservoir, then a CLSM was used to detect the dye distribution within the tooth-restoration interface. Two-way analysis of variance (ANOVA) and the Tukey post-hoc test were used to analyze the SBS results (α=0.05). D30 resulted in a significantly higher mean SBS in the two cement groups than IM and D120 (p<0.05). RU showed significantly higher SBS values than MC regardless of the time of light activation (p<0.05). RU showed less dye uptake confined to the cement-dentin interface compared to the MC groups, which showed dye uptake throughout the entire thickness of the cement layer and gap formation at the interface, especially in the D120 group. The 30-second photo-activation delay group significantly improved the bond strength of SA cements. Delaying the photo-activation to 120 seconds increased pulpal fluid uptake by SA cements and compromised the integrity of the bonded interfaces.

Optimization of a metformin effervescent floating tablet containing hydroxypropylmethylcellulose and stearic acid.

This study optimizes the composition of an effervescent floating tablet (EFT) containing metformin hydrochloride (M) regarding tablet hardness (H), time to dissolve 60% of the embedded drug (t60%), and buoyancy, the floating lag time (FLT). A simplex lattice experimental design has been used comprising different levels of hydroxypropylmethylcellulose (HPMC), stearic acid (SA), sodium bicarbonate (SB) as tablet matrix components, and hardness (H), t60%, FLT as response variables. Two models have been applied to decide which composition will result in Fickian diffusion or in overlapping of two dissolution mechanisms, diffusion and matrix erosion. Three of EFT showed the two dissolution mechanisms but most of EFT showed Fickian diffusion only. Checking the experimental response by a linear, quadratic, special cubic and cubic model using multivariate regression analysis resulted in best fit for the cubic model. Overlaying the results for the cubic model under constraints defined shows the domain of accepted values of response variables. The optimized EFT shall have been included HPMC between 15.6% and 24.2%, SA between 12.8 and 15.6% and SB between 16.1% and 17.5%. The result of this study has been critically evaluated considering analogous EFT described in literature.

APOE genotyping: comparison of three methods.

Apolipoprotein E (apo E) polymorphism is associated with increased risk of cardiovascular and Alzheimer diseases, making its genotyping of potentially predictive value. We developed a rapid, reliable and specific method for determining APOE genotypes by fluorescent resonance energy transfer (FRET) over a high number of samples in a single run using a LightTyper device and dedicated probes. The method, validated with 75 blood samples, was designed to simultaneously detect three common APOE polymorphisms, epsilon(2,) epsilon(3) and epsilon(4), and to identify in a single reaction any of the six following genotypes: epsilon(2)/epsilon(2), epsilon(3)/epsilon(3), epsilon(4)/epsilon(4), epsilon(3)/epsilon(4), epsilon(4)/epsilon(2), epsilon(3)/epsilon(2). The assay involved three phases: (1) DNA extraction, (2) amplification, and (3) melting curve analysis using FRET technique. Briefly, genomic DNA of patients was extracted from total blood. Fragment of APOE was amplified by a first PCR run. Fluorescent labeled probes were added in a second PCR run. FRET genotyping showed following distribution: (1) 1.3% for epsilon(2)/epsilon(2) and epsilon(4)/epsilon(4) homozygotes, (2) 4.0, 6.6 and 14.7% for epsilon(2)/epsilon(4), epsilon(2)/epsilon(3) and epsilon(3)/epsilon(4) heterozygotes, respectively, and (3) 72.0% for epsilon(3)/epsilon(3) homozygotes. Moreover, a careful analysis of the FRET melting curves allowed us to determine the presence of a new polymorphism on the third position of the codon 158 (-AAGCGT-), namely, two nucleotides downstream from the known polymorphism. When the FRET analysis was compared to those obtained by RFLP and sequencing, the presence of this new polymorphism was confirmed only by sequencing thus indicating that RFLP analysis is not always reliable for genotyping.

Homocysteine in relation to C-reactive protein and low-density lipoprotein cholesterol in assessment of cardiovascular risk.

Coronary vascular disease (CVD) is a chronic, multifactorial disease that occurs often in individuals without known risk factors. We investigated the predictive value of homocysteine (Hcy) in relation to C-reactive protein (CRP) and low-density lipoprotein (LDL)-cholesterol in patients with confirmed coronary disease. The study included 87 German and 92 Syrian patients in addition to 87 German and 64 Syrian control individuals. Patients and controls were of comparable age, lifestyles and cultural background. Patients of both ethnic groups had significantly higher concentrations of Hcy and C-reactive protein compared to the controls. The lipids were higher only in Syrian patients compared to the controls. Elevated concentrations of Hcy or that of CRP (>75th percentiles) were associated with increased probability for CVD. In both population groups, the risk increased markedly in subjects who had elevated concentrations of Hcy and CRP or those who had elevated concentrations of Hcy and LDL-cholesterol. The results emphasize that detemination of Hcy may improve the predictive value of C-reactive protein and the LDL-cholesterol. Measurements of these markers are especially important for identification of patients at high risk for CVD.

Agreement among four homocysteine assays and results in patients with coronary atherosclerosis and controls.

BACKGROUND: Hyperhomocysteinemia has been associated with coronary atherosclerosis in many, but not all, prospective and retrospective studies. Some on these inconsistencies may be attributed to methodological variabilities. METHODS: In the present study, three newly commercially available assays and one in-house HPLC assay for total homocysteine (tHcy) were utilized in 99 subjects with angiographically documented atherosclerosis and in 91 community controls matched by age, gender, and smoking history. The in-house assay, a modified Fortin and Genest HPLC method, was compared with the Bio-Rad HPLC assay, the Abbott IMx((R)) fluorescence polarization immunoassay, and a Bio-Rad enzyme-linked immunoassay (EIA) microtiter method. RESULTS: Correlation coefficient values between the in-house HPLC assay and the Bio-Rad HPLC, the Abbott IMx, and the Bio-Rad EIA assays were 0.95, 0.96 and 0.90, respectively. Although tHcy concentrations were higher in cases compared with controls by all four methods, the difference reached statistical significance only with the in-house HPLC procedure (median, 13.5 +/- 6.7 micromol/L in cases vs 10.9 +/- 4.8 micromol/L in controls; P <0. 01, adjusting for covariates), where it was an independent predictor of case or control status, along with hypertension, total cholesterol, and triglycerides. The tHcy distributions in cases and controls demonstrated significant overlap. The number of atherosclerotic major coronary vessels was associated with significantly higher tHcy (P <0.01 for trend) in all four methods. CONCLUSIONS: The three commercial assays for tHcy differed in analytical and clinical performance. Analytically, the Abbott IMx method showed the best comparability with the in-house assay, but clinically, the three commercial methods were similar and did not distinguish cases from controls.

Inflammatory markers in men with angiographically documented coronary heart disease.

BACKGROUND: Recent evidence suggests that atherosclerosis is a chronic inflammatory process. In this study, we examined several markers of inflammation in men with coronary heart disease (CHD) and appropriate controls. METHODS: The concentrations of C-reactive protein (CRP), serum amyloid A (SAA), interleukin-6 (IL-6), and soluble intracellular adhesion molecule (sICAM-1) were examined in 100 men with angiographically documented CHD and 100 age-, gender-, and smoking-matched controls with no history of CHD. We assessed the association of these markers with severity of disease as indicated by >50% obstruction in one vessel (n = 30), two vessels (n = 39), or three vessels (n = 31). RESULTS: Significant increases were noted in serum CRP (median for cases vs controls, 3.4 vs 1.5 mg/L; P <0.0001), SAA (5.9 vs 3.7 mg/L; P <0.005), and IL-6 (2.3 vs 1.7 ng/L; P <0. 013) in patients with CHD compared with controls. These differences remained significant after correction for age, smoking, hypertension, diabetes, and lipid and homocysteine concentrations. Plasma sICAM-1 was not significantly different between the two groups (335 vs 339 microg/L). No significant correlation was seen between these markers and the severity of coronary disease. CONCLUSIONS: Concentrations of CRP, SAA, and IL-6 were increased in patients with CHD but failed to correlate with severity of coronary disease. These markers might reflect the diffuse atherosclerotic process in the vascular system rather than the degree of localized obstruction from coronary lesions.

Absence of myocardial release of troponin T after coronary bypass surgery on a beating heart.

BACKGROUND: Coronary artery bypass grafting (CABG) operations in connection with cardiopulmonary bypass (CPB) appear to be associated with a number of side effects including trauma, cognitive dysfunction and myocardial damage. Accordingly, a current interest in performing CABG on a beating heart begins to emerge. This study examines the premise that conducting CABG on a beating heart limits the extent of myocardial injury and other complications. METHODS: Forty-five consecutive patients underwent CABG on a beating heart (group A, 12 patients) or in connection with CPB (group B, 33 patients). Inclusion criteria were poor left ventricular function and evolving myocardial ischemia or infarction. Results were assessed primarily on the basis of clinical outcome. In addition, measurement of plasma levels of troponin T (TnT), creatine kinase MB (CK-MB) and lactate dehydrogenase (LD) was conducted in 12 patients of group A preoperatively and 24 h after completion of surgery. These biological data were compared with those from control patients who underwent CABG in connection with CPB within the same time span. RESULTS: All patients in groups A and B survived the CABG procedure and those on a beating heart maintained an excellent perioperative hemodynamic measurements. The mean bypass time was 75 +/- 21 min and the mean cardiac standstill was 40 +/- 17 min. The intensive care unit stay was for group A: 18 +/- 4 h, group B: 48 +/- 12 h; and the total hospital stay was for group A: 6 +/- 1 days, group B: 8 +/- 3 days. Angiographic studies showed good anastomatic patency in both groups. Postoperative low output syndrome as indicated by the need of ionotropic drugs for more than 24 h was demonstrated in 4% and 6% of groups A and B, respectively. Limitation of myocardial injury in group A was demonstrated by the minimal increase in postoperative TnT levels (16.0 +/- 0.9 versus 30 +/- 8.0 pg/ml). A similar pattern of changes was observed with other infarction markers including CK-MB and LD. Contrastingly, the pre- and post-operative values of TnT in group B were 18 +/- 1.6 and 790 +/- 140 pg/ml, respectively. CONCLUSIONS: CABG on a beating heart shares many of the positive features of CPB with a distinct advantage of eliminating the intraoperative myocardial ischemia.

Homocysteine levels and coronary heart disease in Syria.

BACKGROUND: Coronary artery disease and disturbances of lipid levels are common in Arab countries. OBJECTIVE: To assess homocysteine as a cardiovascular risk factor. METHOD: We compared 133 men with angiographically documented coronary heart disease with 130 age-matched asymptomatic men. RESULTS: Cases had more hypertension and diabetes and higher levels of total cholesterol, low-density lipoprotein cholesterol, triglycerides, fibrinogen, and homocysteine than did controls. The homocysteine level distribution of cases was shifted toward higher concentrations (P < 0.05) compared with those in controls. When patients with one-vessel, two-vessel, and three-vessel disease were compared, only levels of fibrinogen and homocysteine were associated with the numbers of vessels involved. Homocysteine level was not correlated to fibrinogen and lipid concentrations. A multiple regression analysis revealed that only age (P = 0.06) and smoking (P = 0.04) were marginally related to homocysteine concentrations. Homocysteine concentrations in cases were significantly different than those in controls, even after adjustment for all covariates (P < 0.006). CONCLUSION: Hyperhomocysteinemia is independently associated with coronary artery disease in Arab men. Furthermore, fibrinogen concentrations are also an important risk factor for Arab men.

A xanthomatosis-susceptibility gene may exist in a Syrian family with familial hypercholesterolemia.

Familial hypercholesterolemia (FH) is an autosomal-dominant inherited disorder characterized by high serum low-density lipoprotein (LDL)-cholesterol concentrations, xanthoma formation, and premature atherosclerosis. Homozygous individuals die of vascular disease as children or young adults; heterozygous persons are at high risk for premature cardiovascular death. Mutations in the LDL-receptor gene are responsible for FH. We studied 49 members of a consanguineous Syrian kindred containing 6 homozygous individuals from the same pedigree. Half of the homozygotes had giant xanthomas, while half did not, even though their LDL-cholesterol concentrations were elevated to similar degrees (> 14 mmol/l). Heterozygous FH individuals from this family were also clearly distinguishable with respect to xanthoma size. We performed DNA analysis and were successful in identifying a hitherto not described mutation in this family's LDL receptor. DNA sequence analysis of the LDL-receptor gene revealed a T to C substitution at nucleotide 1,999 in codon 646 of exon 14. We next conducted a segregation analysis, which suggests that a susceptibility gene may explain the formation of giant xanthomas in this family. We raise the hypothesis that the appearance of giant xanthomas in this FH family is controlled by a second gene acting in an autosomal-dominant or recessive fashion. Elucidation of this 'xanthoma' gene may shed additional light on LDL-cholesterol deposition.