Influence of bacterial cell concentration and inorganic anions on lysis of Streptococcus mutans BHT by salivary lysozyme

The aim of this work was to study the influence of bacterial cell concentrations and inorganic anions on lysis of Streptococcus mutans BHT by human salivary lysozyme (HSL). HSL was partly purified from saliva by ion exchange chromatography. The bacteria were grown in a synthetic medium containing ³H-thymidine to monitor DNA release. The experiments demonstrated that release ³H-thymidine was dependent on the bacterial cell concentration and an apparent K_m-value corresponding to approximately 2.9 × 10⁸ cells/ml was calculated. The influence of I^?, Br^?, Cl^?, F^?, HCO₃^? and SCN^? on bacteriolysis was studied. All anions tested were slightly inhibitory on the action of HSL. The inhibition varied from 7 to 76% depending on the ion and ionic strength. The order of addition of HSL and sodium chloride caused different lytic responses. This was reflected by the amount of HSL adsorbed by the bacteria.     

Epidemiology of Van der Woude syndrome from mutational analyses in affected patients from Pakistan

Malik S, Kakar N, Hasnain S, Ahmad J, Wilcox ER, Naz S. Epidemiology of Van der Woude syndrome from mutational analyses in affected patients from Pakistan. Mutations in IRF6 cause Van der Woude syndrome (VWS), one of the most common syndromes associated with cleft lip (CL) with or without cleft palate (CP). The presence of pits on the lower lip of patients is the most characteristic feature of the syndrome. We have identified three novel and seven previously reported IRF6 mutations in 12 of 16 unrelated families segregating VWS from Pakistan. The three newly identified mutations include a frameshift (c.568delG) and two missense mutations c.295G>A (p.G99S) and c.1219T>C (p.S407P). Recent functional studies on IRF6 and the three‐dimensional structure of IRF5 carboxy (C) terminus, a protein encoded by a paralog of IRF6, shed light on the p.S407P substitution. Additionally, the identification of the same mutations responsible for VWS in Pakistan, as reported in other global populations worldwide, marks these residues as mutational hotspots and indicates their essential role in structural stability or function of IRF6. This is the first study of VWS in Pakistan and we estimate that 1 in 100 patients with CL with or without CP (CL/P) are affected in the Pakistani population predominantly from the Punjab area.     

横断面调查在抗菌药物管理PDCA中的应用

目的：探讨将横断面调查应用于抗菌药物管理PDCA中的成效。方法：通过2012年连续4次横断面调查收集资料,应用于抗菌药物管理PDCA循环的计划与检查环节。结果：调查的8项指标中6项有显著改善（P〈0．01）,其余两项无显著改善（P〉0．05）。结论：将横断面调查应用于抗菌药物管理PDCA的各个环节,能改善抗菌药物临床合理应用状况,是提高抗菌药物管理质量行之有效的方法。     

Identification of Ventricular Tachycardia Using Intracavitary Ventricular Electrograms: Analysis of Time and Frequency Domain Patterns

Tachycardia detection by implantable antitachycardia devices using rate alone has major limitations. Several alternative methods have been proposed to distinguish ventricular tachycardia or ventricular fibrillation from normal sinus rhythm using intracardiac electrograms. These methods have not been tested, however, for recognition of ventricular tachycardia in patients with abnormal surface QRS conduction during sinus rhythm or with antiarrhythmic drug therapy. In this study, three techniques for the indentification of ventricular tachycardia from intracavitary bipolar ventricular electrograms were examined and compared: correlation waveform analysis, amplitude distribution analysis, and spectral analysis using Fast Fourier transformation. Thirty episodes of induced monomorphic ventricular tachycardia were analyzed and compared sinus rhythm in four groups of patients with: I. Normal surface QRS conduction during sinus rhythm without antiarrhythmic drug therapy (five episodes); II. Intraventricular conduction delay or bundle branch block during sinus rhythm without antiarrhythmic drug therapy (nine episodes); III. Normal surface QRS conduction during sinus rhythm with antiarrhythmic therapy (six episodes); and IV. Intraventricular conduction delay or bundle branch block during sinus rhythm with antiarrhythmic drug therapy (ten episodes). Correlation waveform analysis had 100% sensitivity and specificity in distinguishing ventricular tachycardia from sinus rhythm, even in the presence of an intraventricular conduction delay, bundle branch block, and antiarrhythmic drug therapy. In contrast, amplitude distribution analysis differentiated 15/30 episodes (50.0%) of ventricular tachycardia from sinus rhythm, and a maximum of 18/30 episodes (60.0%) of ventricular tachycardia were identified by specal analysis using Fast Fourier transformation. Correlation waveform analysis appears to be a reliable technique to discriminate ventricular tachycardia from sinus rhythm using intracavitary ventricular electrograms. Its computational demands are modest, making it suitable for consideration in an implantable antitachycardia device.     

Pacemaker System Failure and Other Events in Children with Surgically Induced Heart Block

Of 1,193 consecutive pediatric (less than 18 years) patients undergoing intracardiac repair from 1975 to 1984, 38 (3.2%) developed surgically induced complete heart block and were treated by permanent pacemaker implantation. Anomalies included complete atrioventricular septal defect = 9 (24%), simple ventricular septal defect = 9 (24%), atrioventricular discordant connection = 8 (212), tetralogy of Fallot = 7 (182), and other complex anomalies = 5 (13%). There were no hospital deaths. follow-up was 100% complete. There were six late deaths = 16%. Actuarial survival was 79 + 9% at 10 years. None of the late deaths were related to disturbance of cardiac rhythm or pacemaker system failure. Twelve patients (32%), required 27 reoperations for various types of pacemaker system failure. Indications for reoperation included: lead failure (44%). Pulse generator failure (44%), and wound sepsis (12%). Actuarial freedom from any pacemaker related reoperation was 50 + 16% at 48 months and 25 + 15% at 96 months. Only first reoperation was found to be an incremental risk factor for subsequent reoperation (p = 0.03). Surgical heart block has been neutralized as a risk factor for hospital death after repair of congenital cardiac defects. The risk of the development of surgical heart block now approaches zero, as indicated by a decreased incidence (1 of 401 = 0.25%) in our institution from 1985 to 1987, as compared to the era 1975 to 1984 (p = 0.001).     

Comparison of the subacute toxicity and efficacy of 3-hydroxypyridin-4- one iron chelators in overloaded and nonoverloaded mice

Five orally effective iron chelators of the 3-hydroxypyridin-4-one series have been administered intraperitoneally to iron-overloaded and nonoverloaded male mice at a dose of 200 mg/kg/24 h for a total of 60 days to investigate the effect on iron loading and toxicity. There was a significant reduction in hepatic iron at the end of the study in the iron-overloaded mice with all compounds studied using chemical iron quantitation (P less than .001) and with Perls' stain (P less than .01). Liver iron removal with the hydroxypyridinones ranged from 37% with CP20 to 63% with CP51, compared with 46% removal for desferrioxamine (DFO). There was no significant reduction in splenic or cardiac iron with any chelator. There were no deaths in iron-overloaded animals receiving any of the hydroxypyridin-4-ones, but significantly more deaths in the nonoverloaded groups as a whole (P less than .03). No weight loss was observed with any chelator. Significant reductions in hemoglobin and white cell count were observed with CP20(L1). No histologic abnormalities of kidney, spleen, bone marrow, or stifle joints were observed. Intracytoplasmic inclusion bodies were observed in the centrilobular hepatocytes of animals administered each of the hydroxypyridin-4-ones, while the DFO-treated and control groups showed no such changes.