High hardness in the biocompatible intermetallic compound ß-Ti3Au.

The search for new hard materials is often challenging, but strongly motivated by the vast application potential such materials hold. Ti3Au exhibits high hardness values (about four times those of pure Ti and most steel alloys), reduced coefficient of friction and wear rates, and biocompatibility, all of which are optimal traits for orthopedic, dental, and prosthetic applications. In addition, the ability of this compound to adhere to ceramic parts can reduce both the weight and the cost of medical components. The fourfold increase in the hardness of Ti3Au compared to other Ti-Au alloys and compounds can be attributed to the elevated valence electron density, the reduced bond length, and the pseudogap formation. Understanding the origin of hardness in this intermetallic compound provides an avenue toward designing superior biocompatible, hard materials.

The effect of pretreatment with renin-angiotensin-aldosterone system blockers on cardioversion success and acute recurrence of atrial fibrillation.

BACKGROUND: Renin-angiotensin-aldosterone system (RAS) may be activated during atrial fibrillation (AF). It is unclear whether RAS inhibition may facilitate cardioversion from AF and may prevent acute recurrence of AF (ARAF). We thus investigated the effect of pretreatment with RAS blockers on cardioversion success and ARAF in patients with AF scheduled for elective cardioversion. METHODS: This observational study included 356 patients with AF undergoing elective pharmacological or electrical cardioversion. Of these patients, 135 were not included based on exclusion criteria and the remaining 221 patients were divided into RAS group (n = 116, 69 male) or non-RAS group (n = 105, 58 male) based on precardioversion use of any RAS blocker. RESULTS: Hypertension, coronary heart disease and heart failure were more frequent in the RAS group. Cardioversion from AF was more successful in the RAS group than in the non-RAS group (%92 vs. %82, p = 0.026). The rate of ARAF was lower in RAS group compared with that in non-RAS group (17% vs. 31%, p = 0.026). In multivariate analysis, pretreatment with RAS blockers in addition to shock number and enlarged left atrium, independently predicted ARAF (OR: 0.33, 95% CI: 0.15-0.75, p = 0.008). Independent predictors of cardioversion success were shock number and left atrial dilatation, but not use of RAS blocker. CONCLUSION: Precardioversion use of RAS blockers may reduce ARAF following successful cardioversion of AF, but did not improve electrical cardioversion.

The effect of conversion type on P wave dispersion in patients with atrial fibrillation.

AIM: The aim of this study was to investigate whether conversion type of atrial fibrillation (AF) to sinus rhythm affects the P wave dispersion (PD) in patients with AF. METHODS: Based on conversion type, 95 consecutive patients with AF<3 months were divided into 3 groups: spontaneous cardioversion (SC) (N.=33, mean age: 60.6+/-11.6 years), pharmacologic cardioversion (PC) (N.=32, mean age: 59.2+/-9.6 years) and electrical cardioversion (EC) (N.= 30, mean age: 65.3+/-10.6 years). P wave duration (maximum and minimum) were measured in 12-lead ECG, and PD was calculated. RESULTS: Left atrial diameter and AF duration were significantly higher in EC (43.6+/-4.8 mm and 794.1+/-815.1 h) than SC (38.5+/-3.9 mm and 13.8+/-18.3 h) and PC (40.9+/-4.5 mm and 65.3+/-148.5 h) groups (P<0.01). P maximum was much longer in EC group compared with SC and PC group (121.6+/-9.7, 108.4+/-6.4 and 115.8+/-8.6 ms, P=0.01, respectively). There was a significant difference in PD among SC, PC and EC groups (44.4+/-9.2, 49.5+/-8.7 and 53.5+/-8.8 ms; P=0.005, respectively). PD correlated with AF duration (r=0.36, P=0.03), left atrial diameter (r=0.45, P=0.002) and conversion type (r=0.29, P=0.03). However, there was no significant association between PD and conversion type in multivariate analysis. The prolonged PD resulted from AF duration (P=0.01) and the left atrial size P=0.001). CONCLUSION: This study suggests that conversion type of AF to sinus rhythm has no effect on P wave duration and independent of AF duration and the left atrial diameter.

Effects of intravenous N-acetylcysteine on periprocedural myocardial injury after on-pump coronary artery by-pass grafting.

AIM: Myocardial ischemia/reperfusion injury in patients undergoing coronary artery by-pass grafting (CABG) involves the reperfusion-induced conversion of reversible injured myocardial and endothelial cells. N-acetylcysteine (NAC) has a potential being the minimization of the impact of reperfusion injury. The aim of this study was to evaluate the effects of intravenous NAC on periprocedural myocardial injury after CABG. METHODS: The population of this prospective-randomized, double blind, placebo controlled study consisted of 40 patients undergoing on-pump CABG. All the patients were treated with standard medical therapy and eligible patients were randomized to NAC group (N.=19; intravenous infusion for 1 hour before the procedure at a dose of 50 mg/kg, followed by intravenous infusion for 48 hours after the operation at a dose of 50 mg/kg/day) and placebo (saline) group (N.=21). The study drug and placebo infusions were set to infuse at the same rate. RESULTS: Demographic and procedural variables were similar in the both groups (All P>0.05). Creatine kinase MB isoform (CK-MB) mass levels did not significantly differ between the groups at both preoperative and postoperative periods. Similarly, cTnT levels were similar in the groups at all periods. Eight patients in the NAC group and 7 in the placebo group had increased CK-MB >3 times normal value. However, only 3 patients in the NAC group experienced CK-MB>5 times normal value. CONCLUSION: Results of this study indicated that periprocedural use of NAC as intravenously did not attenuate myocardial damage after on-pump CABG surgery.

Prevalence and annual risk of tuberculosis infection in Edirne, Turkey.

Tuberculosis is still an important problem in developing countries. A total of 3,774 students from primary schools in Edirne, Turkey were included in this study in order to determine the annual infection risk for the year 1994. Five tuberculin units of purified protein derivative were applied using a Mantoux test and evaluated. The mean induration diameter was 14.6 mm. A total of 51.6% of the students were found to be sensitive to tuberculin. The annual infection risk of tuberculosis was found to be 1.51%, lower than that found in 1987. Other studies from Turkey have reported lower values than ours. We did not diagnose any cases of tuberculosis. We revealed that the annual infection risk among primary schoolchildren in Edirne is close to the average for Turkey and thus tuberculosis is still a serious risk for these children. Tuberculosis remains an important public health problem in Turkey and is partially attributable to socioeconomic difficulties.

Castleman's disease in the porta hepatis.

We report the CT, ultrasonographic, and pathologic features of a localized forms of Castleman's disease in the porta hepatis due to their unusual location. Our report suggests that the CT and the ultrasonographic features of Castleman's disease in these locations without calcifications is nonspecific.

Protruding urethral leiomyoma obscuring vaginal introitus: case report.

Leiomyoma is quite rare in the female urethra. We report an additional case to 29 reported in the literature. A multiparous woman presented with a complaint of a gradually enlarging mass causing dyspareunia for the last seven months. The mass was originating from the upper part of the distal urethra with a relatively thin stalk covered by squamous epithelia, and immunohistopathological examination confirmed it as leiomyoma.