Evaluation of external apical root resorption caused by fixed functional treatment of class II malocclusion : Cast splint Herbst appliance vs. Forsus fatigue resistant device

INTRODUCTION

The aim of this study was to evaluate and compare the effects of class II fixed functional treatment with a cast splint Herbst appliance (HA; Herbst Set I, Dentaurum, Ispringen, Germany) and Forsus fatigue resistant device (FRD; 3M Unitek Corp., Monrovia, CA, USA) on external apical root resorption (EARR) in posterior teeth.

METHODS

In all, 40 patients (15 male and 25 female) with class II division 1 malocclusion were treated with two fixed functional appliances: HA (20 patients, mean age 14.60 ± 1.14 years) and FRD (20 patients, mean age 14.15 ± 1.28 years). The vestibular lengths of the first molars and premolars were measured on panoramic radiographs and converted to actual tooth length using the magnification coefficient (MC), which was calculated using dental models. Intragroup comparisons of pre- and posttreatment tooth lengths were performed with the paired t‑test and Wilcoxon signed-rank test, while intergroup comparisons were performed with the Mann-Whitney U test.

RESULTS

Pretreatment tooth length values decreased significantly with HA and FRD therapies for all posterior teeth. The maximum resorption was observed in the mandibular first premolar with a mean of 0.81 mm following HA and 1.55 mm following FRD treatment. While no significant difference existed between the EARR values of the HA and FRD groups for maxillary teeth, the amount of EARR of mandibular posterior teeth in the FRD group was significantly higher than in the HA group.

CONCLUSIONS

In patients treated with HA or FRD, the tooth length of posterior teeth decreased to a clinically minor but statistically significant degree. The root resorption effect of FRD therapy in mandibular posterior teeth was significantly higher than that of HA therapy.

Interaction between Beta-Blockers and Contrast Media during Intracoronary Administration in Rabbit Heart

The effects of ionic, meglumine sodium diatrizoate (Urografin 76) and nonionic, iohexol contrast media were examined in the absence and presence of propranolol, a beta-blocker having nonspecific membrane stabilizing action and atenolol, a beta-blocker lacking nonspecific membrane stabilizing action on Langendorff-perfused rabbit hearts. Contrast medium, 0.7 ml, was injected into the aortic root in the absence and presence of 10−7 and 10−5 M beta-blocker to observe the changes in resting tension, force of contraction, rate of contraction, heart rate and PR interval. Beta-blockers and contrast media interact in affecting myocardial contractility, heart rate and atrioventricular conduction. The interaction is milder when the beta-blocker lacks membrane stabilizing activity and the contrast medium is nonionic.

The long-term effects of low-dose 17β-estradiol and dydrogesterone hormone replacement therapy on 24-h ambulatory blood pressure in hypertensive postmenopausal women: a 1-year randomized, prospective study

OBJECTIVE

The aim of this study was to assess the long-term effects of low-dose oral hormone replacement therapy (HRT) on 24-h blood pressure in hypertensive postmenopausal women.

STUDY DESIGN

In this 12-month, prospective study, 66 postmenopausal women with mild or moderate hypertension were randomly assigned to receive either HRT with 1 mg/day micronized 17beta-estradiol sequentially combined with 10 mg/day dydrogesterone for 14 days of each 28-day cycle, or no therapy. Ambulatory blood pressure measurements were recorded for a 24-h period at baseline and after 12 months of treatment or follow-up.

RESULTS

Blood pressure did not differ significantly between the groups at baseline. After 12 months, there were falls in 24-h systolic, diastolic and mean arterial blood pressure in both the HRT and control groups; only the fall in mean arterial blood pressure in the HRT group achieved statistical significance (-2.0 +/- 0.8 mmHg, p < 0.01). While there was no significant decrease in daytime systolic or mean arterial blood pressure in either group, a significant decrease in diastolic blood pressure (-1.8 +/- 10 mmHg, p < 0.001) was observed in the HRT group. Night-time systolic and mean arterial blood pressure also decreased significantly (p < 0.001) in the HRT group (-3.0 +/- 1.5 mmHg and -2.2 +/- 0.6 mmHg, respectively), but no significant change was observed in the control group.

CONCLUSION

Low-dose oral HRT caused significant falls in both daytime and night-time ambulatory blood pressure in postmenopausal women with mild or moderate hypertension.

Thrombus in the main pulmonary artery of a patient with thromboangiitis obliterans: observation by transthoracic echocardiography

We describe a 45-year-old man with thromboangiitis obliterans. He had a large immobile wall-adherent thrombus located in the main pulmonary artery, which was detected by transthoracic echocardiography. The pulmonary arterial involvement in this patient may suggest that thromboangiitis obliterans is a generalized vascular disease. We conclude that pulmonary artery should be thoroughly examined for thrombi in thromboangiitis obliterans patients who present with signs and symptoms of right heart failure. Transthoracic echocardiography should be the initial mode of examination in these patients.

Exercise performance in patients with dilated cardiomyopathy: relationship to resting left ventricular function

Relationship between maximal exercise tolerance and resting indexes of left ventricular systolic and diastolic function were evaluated in 35 men, aged 55.1 +/- 10.4 years, with dilated cardiomyopathy. Clinical diagnosis of dilated cardiomyopathy was confirmed with M-mode echocardiography (M-mode echocardiographic end-diastolic dimension >55 mm, fractional shortening <25%, increased E point septal separation). Coronary angiography was considered mandatory for exclusion of patients with coronary artery disease. Patients with mitral regurgitation (> or =grade 2) and rhythm other than sinus were excluded. According to the functional classification of New York Heart Association 6 patients were in class I, 11 in class II, 12 in class III and 6 in class IV. Left ventricular ejection fraction (LVEF), stroke volume (SV) and left ventricular end-diastolic pressure (LVEDP) were measured with contrast angiography. Peak early (VE) and late (VA) transmitral filling velocities and their ratio (E/A), isovolumetric relaxation time (IRT) and deceleration time (DT) were computed from pulsed wave Doppler echocardiograms. On completion of all resting measurements, patients underwent symptom limited upright treadmill exercise testing using a modified Naughton protocol and maximal exercise performance metabolic equivalent work load (NETS) was calculated from the speed, incline and length of time at the stage using standard tables to make interpatient comparisons. Significant correlation has been found between NYHA class and METS (r= -0.77, P<0.001). However NYHA class II and NYHA class III patients were found to have similar METS (P=0.317). Patients were further divided into two groups on the basis of exercise data. Group I consisted of 22 patients with relatively preserved exercise tolerance (> or =4 METS) and Group II included 13 patients with impaired exercise tolerance (> or =4 METS). This arbitrary classification was based upon previously described survival differences in these two groups. There were no differences between two groups in terms of age, gender distribution (all were male), heart rate and arterial blood pressure. LVEF, LVEDP, stroke volume, VE, VA, E/A, IRT and DT were also similar between two groups. Strong positive correlation was observed between LVEDP and VE (r=0.74) while IRT and VA negatively correlated with LVEDP (r= -0.77 and r= -0.81 respectively) but neither of resting indexes of left ventricular systolic and diastolic function showed significant correlation with METS and exercise duration.

Interaction between beta-blockers and contrast media during intracoronary administration in rabbit heart

The effects of ionic, meglumine sodium diatrizoate (Urografin 76) and nonionic, iohexol contrast media were examined in the absence and presence of propranolol, a beta-blocker having nonspecific membrane stabilizing action and atenolol, a beta-blocker lacking nonspecific membrane stabilizing action on Langendorff-perfused rabbit hearts. Contrast medium, 0.7 ml, was injected into the aortic root in the absence and presence of 10(-7) and 10(-5) M beta-blocker to observe the changes in resting tension, force of contraction, rate of contraction, heart rate and PR interval. Beta-blockers and contrast media interact in affecting myocardial contractility, heart rate and atrioventricular conduction. The interaction is milder when the beta-blocker lacks membrane stabilizing activity and the contrast medium is nonionic.

Analysis of high frequency QRS potentials observed during acute myocardial infarction

The value of high frequency QRS potentials (HFQRS) during acute myocardial infarction (AMI) was assessed to define infarct size and prognosis. HFQRS were recorded by signal-averaged ECG with 150-250 Hz frequency ranges, using X, Y, Z orthogonal leads. Recordings were obtained in surviving AMI patients (n = 33, 12 inferior, 11 anterior, 10 anterior-inferior) on the first and tenth days, but in non-survived patients (n = 5, 2 inferior, 1 anterior, 2 anterior-inferior) only on the first day. Additionally, the frequency of ventricular tachycardia (VT) was evaluated by 24-h Holter monitoring in all patients at the same days. The control group consisted of 11 healthy people. In surviving AMI patients, RMS voltage of vector magnitude reduced in anterior and anterior-inferior MI but filtered QRS duration was longer in inferior MI than normals (P < 0.05, < 0.05, < 0.01, respectively). In nonsurvived patients, RMS voltages of leads X, Y, Z and vector magnitude were lower than normals (P < 0.01, < 0.05, < 0.01, < 0.01, respectively) and surviving AMI patients (P < 0.01, < 0.05, < 0.05, < 0.05, respectively), the filtered QRS duration was found to be longer than normals and survived patients (P < 0.01, < 0.01). In patients who had VT on Holter monitoring, filtered QRS duration was significantly longer than in patients without VT (P < 0.05). As a result, HFQRS was important for defining infarct size but not malignant ventricular arrhythmias. VT was related to filtered QRS duration. HFQRS may offer significant prognostic information and contribute to early risk stratification of AMI patients.

The role of arrhythmia and left ventricular dysfunction in patients with acute myocardial infarction and bundle branch block

To determine the immediate and remote prognostic significance of bundle branch block (BBB) associated with acute myocardial infarction (AMI), 40 patients with AMI and BBB were studied. One hundred forty-four patients with AMI but without BBB were evaluated during the in-hospital phase and 45 of them were taken as a control group. These patients were followed for an average of 15 months (3-28 months). Arrhythmias and left ventricular function were investigated with 24-hr Holter monitoring and echocardiography, respectively. The hospital mortality was significantly greater in patients with BBB than in the control group (32.5% vs 10.4%, p < 0.001). The main cause of mortality was pump failure in the group with BBB (76.9%) and ventricular fibrillation in the control group (53.3%). The peak creatine kinase level was significantly higher in the group with BBB than in the control group (2094.8 +/- 288.4 IU/L vs 416.7 +/- 30.5 IU/L, p < 0.001). In patients with BBB prophylactic temporary pacemaker insertion was not found to improve the hospital mortality rate. In the hospital phase, although 32% of the patients with BBB had complicated arrhythmias (multiform, paired VPB, runs, R-on-T) the cause of death in 10 of the 13 patients who died was pump failure but not arrhythmia. In patients with BBB the wall motion index and the number of patients who had a left ventricular aneurysm were greater than in patients without BBB (9.5 +/- 0.9 vs 6.3 +/- 0.6, p < 0.01 and 52.0% vs 14.3%, p < 0.01, respectively). In patients with BBB follow-up mortality (12.0%) was lower than hospital mortality (32.5%). During the follow-up period there was no significant difference between patients with BBB and those without with regard to complicated arrhythmias (14.8% vs 15.6%). These results indicate that the main cause of poor prognosis during the hospital period in patients with AMI and BBB was not arrhythmia or conduction disturbance but severe pump failure due to extensive myocardial necrosis. Prophylactic temporary pacemaker insertion did not improve the hospital mortality rate of these patients, and patients with AMI and BBB who survive the in-hospital phase after infarction have a good prognosis during the following 15 months.

Is sublingual nifedipine administration superior to oral administration in the active treatment of hypertension?

Nifedipine, a calcium-channel-blocking agent, was administered orally to 44 untreated patients (Group A) and sublingually to 51 untreated patients (Group B) who had a diastolic blood pressure more than 90 mm Hg and systolic blood pressure more than 140 mm Hg. The mean pretreatment systolic and diastolic blood pressure values were 185.3 +/- 26.0 and 115.1 +/- 13.4 mm Hg in Group A patients and 193.6 +/- 23.1 and 118.1 +/- 14.1 mm Hg in Group B patients respectively (p greater than 0.05). The hypotensive activity of nifedipine was observed at the tenth minute in both groups. Mean systolic and diastolic pressures were 168.9 +/- 23.7 and 101.9 +/- 14.2 mm Hg in Group A and 170.6 +/- 26.2 and 103.0 +/- 15.8 mm Hg in Group B, (p less than 0.001) Diastolic blood pressures dropped under 100 mm Hg at the twentieth minute in both groups. Maximal reduction of blood pressure was observed at the fortieth minute in both groups and the degree of reduction in blood pressure was also the same (mean systolic and diastolic blood pressures: 143.7 +/- 22.1 and 86.9 +/- 11.7 in Group A and 148.7 +/- 21.4 and 91.7 +/- 17.0 in Group B (p less than 0.05). The authors conclude that sublingual nifedipine administration is not superior to oral nifedipine administration (in capsular form) in the acute treatment of hypertension.

Rate-dependent ST segment depression--a case report

A patient with resting heart rate over 100 beats per minute (bpm) displayed 1.5-2 mm ST segment depression in her ECG during daily activities. She had unprovoked further increase in her heart rate up to 145 bpm, and during these episodes, her ECG displayed further ST segment depression up to 3 mm and of 0.12 second duration. An organic cause could not be found to explain her sinus tachycardia. Results of all laboratory investigations, including coronary angiography, were normal. It was observed that during an episode of reflex vagotonia, when her heart rate was below 95 bpm, her previously depressed ST segments became isoelectric. With the thought that this patient's ST segment depression was rate-dependent, carotid sinus massage was performed, and when the heart rate slowed to 95 bpm her depressed ST segments became isoelectric. The same response was accomplished with beta blockers. Sympathetic hyperactivity was thought to be the most likely mechanism of ST segment depression in this patient. A critical increase in heart rate caused these ECG abnormalities.

Aortic root and left atrial wall motion. An echocardiographic study

The echocardiographically recorded movement of the aortic root was studied by analysing the relation between posterior aortic wall motion and other intracardiac events. The systolic anterior movement of the aortic root continued beyond aortic valve closure and in cases with mitral regurgitation began significantly earlier than in normal subjects. The diastolic rapid posterior movement began after mitral valve opening but did not occur in patients with mitral stenosis. The total amplitude of aortic root motion was increased in patients with mitral regurgitation, diminished in cases of mitral stenosis, and was normal with aortic regurgitation. In patients with atrioventricular block an abrupt posterior movement followed the P wave of the electrocardiogram irrespective of its timing in diastole. These observations correlate with the expected changes in left atrial volume during the cardiac cycle both in the normal subjects and patients with heart disease. The results support the hypothesis that phasic changes in left atrial dimension are largely responsible for the echocardiographically observed movement of the aortic root and indicate a potential role for echocardiography in the analysis of left atrial events.