Effectiveness and Color Stability of Resin Infiltration on Demineralized and Hypomineralized (MIH) Enamel in Children: Six-month Results of a Prospective Trial

INTRODUCTION

To evaluate the masking effect and color stability of resin infiltration treatment in demineralized (white spot lesion) and hypomineralized (molar incisor hypomineralization) enamel lesions of young permanent anterior teeth.

METHODS

Eighty-four (84) anterior teeth with molar incisor hypomineralization or white spot lesions were treated with resin infiltration. The CIE L*a*b* values of sound enamel and enamel lesions were assessed with spectrophotometer and digital image analysis at baseline, immediate postop, 1 week and 6 months. The difference in ΔL, Δa, Δb, and ΔE measurements between sound enamel and the enamel lesions was compared using the repeated analysis of variance (ANOVA) test at p < 0.05.

RESULTS

The enamel lesions were clearly discernible from the sound adjacent enamel at baseline. After resin infiltration, there was a significant drop in ΔE values of sound enamel and enamel lesions compared to baseline, and this difference did not change for 6 months, indicating a durable masking effect. At baseline and after 6 months, there was no significant difference in the ΔE values of the test groups.

CONCLUSION

The demineralized and hypomineralized enamel defects were effectively masked by resin infiltration, which remained clinically stable for 6 months.

Application of advanced shearing techniques to the calibration of autocollimators with small angle generators and investigation of error sources

The application of advanced error-separating shearing techniques to the precise calibration of autocollimators with Small Angle Generators (SAGs) was carried out for the first time. The experimental realization was achieved using the High Precision Small Angle Generator (HPSAG) of TUBITAK UME under classical dimensional metrology laboratory environmental conditions. The standard uncertainty value of 5 mas (24.2 nrad) reached by classical calibration method was improved to the level of 1.38 mas (6.7 nrad). Shearing techniques, which offer a unique opportunity to separate the errors of devices without recourse to any external standard, were first adapted by Physikalisch-Technische Bundesanstalt (PTB) to the calibration of autocollimators with angle encoders. It has been demonstrated experimentally in a clean room environment using the primary angle standard of PTB (WMT 220). The application of the technique to a different type of angle measurement system extends the range of the shearing technique further and reveals other advantages. For example, the angular scales of the SAGs are based on linear measurement systems (e.g., capacitive nanosensors for the HPSAG). Therefore, SAGs show different systematic errors when compared to angle encoders. In addition to the error-separation of HPSAG and the autocollimator, detailed investigations on error sources were carried out. Apart from determination of the systematic errors of the capacitive sensor used in the HPSAG, it was also demonstrated that the shearing method enables the unique opportunity to characterize other error sources such as errors due to temperature drift in long term measurements. This proves that the shearing technique is a very powerful method for investigating angle measuring systems, for their improvement, and for specifying precautions to be taken during the measurements.

Atrial fibrillation after coronary artery bypass grafting in elderly patients: incidence and risk factor analysis

OBJECTIVE

New-onset atrial fibrillation (AF) is the most frequent arrhythmic complication after coronary artery bypass grafting (CABG). Elderly patients who undergo this operation may have a different risk profile from the general population. The aim of this study was to identify risk factors for post-CABG AF in the elderly population.

METHODS

Between September 2001 and December 2005, 426 elderly patients (age >/= 65 years) underwent CABG at our center. Ninety-one developed post-CABG AF (AF group), and the other 335 (no-AF group) did not develop this complication. Multivariate analysis (odds ratio, +/- 95 % CI, P value) was used to identify independent clinical predictors of post-CABG AF.

RESULTS

The incidence of post-CABG AF in elderly patients during the study period was 21.4 %. Multivariate analysis identified age (OR 1.07, P < 0.009), age >/= 75 years (OR 1.77, P < 0.042), preoperative renal insufficiency (OR 5.09, P < 0.035), EuroSCORE (OR 1.18, P < 0.038), and cross-clamping time (OR 1.02, P < 0.012) as predictors of AF occurrence. The AF group had a significantly longer mean intensive care unit (ICU) stay (3.8 +/- 4.7 vs. 2.5 +/- 1.3 days for AF vs. no-AF; P = 0.0001), and a significantly higher proportion of patients with prolonged (>/= 6 days) ICU stays (8.8 % vs. 3.2 %, respectively; P = 0.033). Hospital mortality was 3.2 % in the no-AF group and 2.2 % in the AF group ( P = 0.74).

CONCLUSION

This study of elderly patients reveals some novel predictors of post-CABG AF, most notably preoperative renal insufficiency and EuroSCORE. It is important to identify risk factors for post-CABG AF in all patient groups as this knowledge might lead to better prevention of this problem and its potential consequences.

Effects of Pretreatment with Different Topical Vasodilators on Blood Flow in the Internal Mammary Artery: A Prospective Randomized Study

BACKGROUND

This study was conducted to investigate how brief pretreatments with 4 different vasodilators applied topically at normal body temperature affect blood flow in the internal mammary artery.

METHODS

One hundred patients who had an internal mammary artery mobilized as a pedicle for coronary artery bypass grafting were randomly assigned to one of 5 groups of equal size (20 subjects in each). Each group of pedicles was treated with a different topical solution: normal saline (control), nitroglycerin, diltiazem, papaverine, or adenosine. Internal mammary artery flow and hemodynamic measurements were recorded immediately after harvesting and after 5 minutes of immersion in a tube filled with test solution (50 mL at 37 degrees C). Results for each study variable were compared within and between groups, and posttreatment-to-pretreatment ratios were also calculated and compared.

RESULTS

All 4 vasodilator groups showed a significant increase in internal mammary artery flow rate from pretreatment to posttreatment, whereas the saline group did not. There were no significant differences among the 5 groups' pretreatment flow rates (P = .526) or posttreatment flow rates (P = .194). The mean ratio values (posttreatment-to-pretreatment) for flow rate were 1.08 +/- 0.17 in the saline group, 1.74 +/- 0.17 with nitroglycerin, 1.77 +/- 0.49 with diltiazem, 1.82 +/- 0.59 with papaverine, and 1.57 +/- 0.54 with adenosine. Post hoc analysis revealed that the mean ratio values for flow rate in the 4 vasodilator groups were significantly higher than the corresponding ratio in the saline group.

CONCLUSIONS

Brief treatment of the internal mammary artery with topical vasodilators at normal body temperature significantly increases blood flow in this vessel. The data from this study are particularly valuable in relation to off-pump surgery, in which this vessel is usually anastomosed soon after it is harvested.

Complete myocardial revascularization using arterial grafts only in patients with unstable angina: impact on early outcome

OBJECTIVE

The aims of this study were 1) to assess early clinical outcomes for patients with unstable angina (UA) who undergo urgent/emergent coronary artery bypass grafting (CABG); and 2) to evaluate the feasibility and safety of complete revascularization using strictly arterial grafts in this patient group.

PATIENTS AND METHODS

Between September 2001 and May 2005, a total of 961 patients underwent CABG at our center. One hundred and sixty-seven (17.4 %) of these individuals underwent urgent or emergent CABG because of UA, and 794 (82.6 %) underwent elective CABG for stable angina (SA). Of the 167 patients with UA, 59 (35.3 %) underwent complete revascularization using arterial grafts only (AO subgroup: internal thoracic arteries and radial arteries) and the other 108 received a combination of arterial and venous grafts (AV subgroup: 1 internal thoracic artery plus saphenous vein grafts).

RESULTS

The UA group had a significantly higher proportion of women and a significantly higher rate of left main coronary artery disease than the SA group ( P = 0.016 and P = 0.0001, respectively). Cardiopulmonary bypass time was significantly longer in the UA group ( P = 0.01). Higher proportions of the UA group required inotropic support ( P = 0.001), intra-aortic balloon pump support ( P = 0.001), and re-exploration for bleeding or cardiac tamponade ( P = 0.005). This group also had a significantly longer mean time on mechanical ventilation ( P = 0.001) and a longer mean intensive care unit stay ( P = 0.01). The rates of operative mortality (first 30 days) in the SA and UA groups were 1.8 % and 6 %, respectively ( P = 0.001). There were no statistical differences between the AO and AV subgroups with respect to any of the preoperative or intraoperative findings. The AO group had a significantly shorter mean intensive care unit stay than the AV group ( P = 0.05). The AV group had a roughly fivefold higher operative mortality than the AO group (8.3 % vs. 1.7 %, respectively), but this difference was not statistically significant ( P = 0.17).

CONCLUSION

Urgent or emergent CABG in the setting of UA is associated with increased but acceptable rates of mortality and morbidity. Complete myocardial revascularization using arterial grafts only (combinations of internal thoracic and radial arteries) is feasible and safe in this patient group.

Surgical approach for Stanford type A aortic dissection in a patient with Marfan syndrome and pectus excavatum

Acute Stanford type A aortic dissection in a patient with severe pectus excavatum constitutes a surgical emergency and presents a major challenge for the surgeon. Decisions must be made regarding the operative approach and whether the pectus excavatum should be corrected during the same session. Herein, we describe a case of acute aortic dissection in a patient who had Marfan syndrome with severe pectus excavatum. Combined partial upper sternotomy and left anterior thoracotomy provided excellent surgical exposure, and the aortic root and ascending aorta were completely replaced. The procedures were successful, and the patient recovered. Technical and surgical considerations led us to postpone concomitant correction of the pectus excavatum.

Topical Vasodilators for Preventing Radial Artery Spasm during Harvesting for Coronary Revascularization: Comparison of 4 Agents

BACKGROUND

There is still controversy about which vasodilator solution is best for storing radial artery (RA) conduits prior to coronary artery bypass grafting. The aim of this pilot study was to investigate how 4 different topical vasodilators applied during RA harvesting affect blood flow with the vessel in situ.

MATERIALS AND METHODS

The subjects were 85 patients who underwent RA harvesting in preparation for coronary artery bypass grafting. Each case was assigned to 1 of 5 groups (17 RAs each) that were treated with different solutions: normal saline (control), nitroglycerin, diltiazem, papaverine, and adenosine. Standard clinical concentrations were used. The RA was partially harvested (pedicle attached proximally) and flow rates and hemodynamic parameters (mean arterial pressure, heart rate, central venous pressure) were recorded at 2 time points: (1) pretreatment and (2) after 5 minutes of immersion in 60 mL of treatment solution. Results were compared within and between groups, and post-treatment-to-pretreatment ratios were calculated for each variable.

RESULTS

There were no significant differences among the groups' mean pretreatment flow rates (P = .979) or mean posttreatment flow rates (P = .069). All except the diltiazem group showed a significant rise in mean flow rate from pretreatment to posttreatment. The mean posttreatment-to-pretreatment ratios for RA flow rate were 1.28 +/- 0.39 in the saline group, 1.85 +/- 0.72 in the nitroglycerin group, 1.31 +/- 0.48 in the diltiazem group, 1.37 +/- 0.64 in the papaverine group, and 1.23 +/- 0.42 in the adenosine group. Only the mean flow ratio in the nitroglycerin group was significantly higher than that in the saline group (P = .003). The mean flow ratios in the other vasodilator groups were not statistically different from the flow ratio in the saline group.

CONCLUSIONS

These preliminary results indicate that topical application of nitroglycerin solution effectively prevents perioperative spasm of the RA in patients undergoing coronary artery bypass surgery. The authors recommend this solution for preparation and storage of RA grafts. Randomized controlled trials with power analysis will give more definitive information.

Does cardiopulmonary bypass alter plasma level of tumor markers? CA 125 and carcinoembryonic antigen

BACKGROUND

In addition to malignant diseases, acute and chronic inflammations may elevate plasma levels of tumor markers CA 125 and carcinoembryonic antigen (CEA). Cardiopulmonary bypass (CPB) causes a generalized inflammatory response. In this study, we have investigated the effect of CPB on plasma levels of CA 125 and CEA.

METHODS

We measured plasma levels of CA 125 and CEA in patients undergoing coronary artery bypass grafting (CABG) with CPB (Group 1, n = 21), and in patients who underwent off-pump CABG, that is, without CPB (Group 2, n = 16). Blood samples were collected preoperatively, and on postoperative days 1, 6, and 12.

RESULTS

Within both groups, CEA plasma levels were not significantly influenced in any samples. Comparing with preoperative values, CA 125 values elevated significantly on postoperative days 6 and 12 within both groups. It was observed that the elevation of CA 125 plasma levels in these samples were significantly higher in Group 1.

CONCLUSIONS

The results indicate that CPB elevated plasma level of CA 125. However, clinical importance of this finding needed further evaluation.

Renal afferent impulses, the posterior hypothalamus, and hypertension in rats with chronic renal failure

Hypertension in 5/6 nephrectomized (CRF) rats is partly related to increased activity of the sympathetic nervous system. We have previously shown a greater norepinephrine turnover rate in the posterior hypothalamic nuclei and locus coeruleus of CRF than control rats. Dorsal rhizotomy prevented the rise in blood pressure and the increase in NE turnover rate in the posterior hypothalamus and the locus coeruleus. The studies suggest that afferent impulses from the kidney to central integrative structures in the brain may be responsible for hypertension in CRF rats. To further evaluate the role of renal afferent nerves in the regulation of blood pressure, and whether renal afferent pathways integrate with the posterior hypothalamus, we studied the effects of an intrarenal injection of 50 microliters of 10% phenol on blood pressure and NE secretion from the posterior hypothalamus of Sprague-Dawley rats. Mean arterial pressure increased from 89 +/- 4.0 to 114 +/- 4.3 mm Hg in rats which received intrarenal injection of phenol, but it did not change in rats that received vehicle (95 +/- 4.3 and 89 +/- 3.6 mm Hg, respectively). Renal denervation totally prevented the increase in blood pressure caused by intrarenal injection of phenol. The secretion of NE from the posterior hypothalamus increased from 139 +/- 4.8 to 250 +/- 9.9 pg/ml (P < 0.01) in rats that received intrarenal phenol, but it did not change in rats which received vehicle or in those with renal denervation. In CRF rats NE secretion from the posterior hypothalamus was greater than in control and CRF rats subjected to dorsal rhizotomy. These studies show that afferent impulses from an injured kidney increase NE secretion from the posterior hypothalamus and raise blood pressure. NE secretion is higher in the posterior hypothalamus of CRF than control rats. The posterior hypothalamus appears to be an important integrative structure of the sympathetic regulation of blood pressure.