Septal alcohol ablation in hypertrophic obstructive cardiomyopathy: improving cardiac function by generating a myocardial scar.

We read with great interest the article by van Dockum et al.¹on the improvement of systolic myocardial function of the leftventricular (LV) lateral (free) wall in patients with hypertrophic     

Doppler echocardiographic evaluation of right ventricular diastolic function in isolated valvular aortic stenosis.

BACKGROUND AND AIM OF THE STUDY: Left ventricular diastolic function (LVDF) in patients with aortic stenosis (AS) has been adequately studied, in contrast to right ventricular diastolic function (RVDF). In this study, RVDF in patients with AS was evaluated using pulsed-wave Doppler echocardiography. METHODS: The study population comprised 20 patients with isolated AS (mean age 53.7 +/- 6.5 years) and 20 healthy volunteers (control group, mean age 52.6 +/- 8.8 years). The diastolic indices of right ventricular (RV) function were calculated using transtricuspid and transpulmonary Doppler flow velocities. Statistical analysis was performed using Student's t-test. There was no statistically significant difference between patients and controls with regard to age, height, bodyweight, heart rate, systolic and diastolic blood pressures, end-diastolic and end-systolic left ventricular (LV) diameter, LV fractional shortening and RV end-diastolic diameter. RESULTS: RV diastolic indices in patients (versus controls) were as follows: E/A ratio of transtricuspid flow waves was significantly lower (0.88 +/- 0.20 versus 1.25 +/- 0.33, p < 0.001); deceleration time of E wave was significantly longer (184 +/- 3 versus 127 +/- 3 ms, p < 0.001); atrial filling fraction was significantly augmented (43.1 +/- 7.7 versus 33.6 +/- 7.6%, p < 0.001); and isovolumic relaxation time was significantly prolonged (116 +/- 73 versus 31 +/- 15 ms, p < 0.001). There was no statistically significant correlation between diastolic indices and interventricular septum thickness and LV mass index. CONCLUSIONS: RVDF in AS patients is impaired, reflecting abnormal relaxation.     

Antigenic stimulation in T-cell cultures in cardiomyopathies: differences in cytokine profiles

Immune-mediated mechanisms are involved in the pathogenesis of cardiomyopathies. In this study, we investigate which pattern of immune response (Th₁ or Th₂) lies behind these diseases by analysing the basic cytokines secreted from PHA-cultured T lymphocytes and determining what differences, if any, exist between dilated cardiomyopathy (DMC) and hypertrophic cardiomyopathy (HCM). Two groups of patients were studied: 10 patients with DCM and 10 patients with HCM. Age- and sex-matched healthy individuals were used as controls. PHA-cultured T lymphocytes in the presence or absence of different myocardial antigen (MA) concentrations were measured. Interleukine-2 (IL-2), Interleukine-6 (IL-6) and Interferon-γ (IFN-γ) levels were measured in culture supernatants by an ELISA method. At the same time, delayed-type hypereactivity (DTH) against the same antigenic preparation was measured by the leukocyte migration inhibitory index technique. Patients were subdivided into DTH-positive and DTH-negative and re-examined for IL-2 cytokine expression. IL-6 levels were found to increase both in the presence and in the absence of MA in the patient groups compared to the controls. IL-2 levels were decreased in both groups, in an antigen dose-related manner. Anergic patients showed a further reduction in IL-2 levels for both groups of patients. IFN-γ remained unaffected in the patient groups. Almost half of the patients exhibited anergy to the DTH reaction against MA. We conclude that, upon antigenic stimulation, the initially mounted immune response (increased IL-6) is somehow blocked/switched off in patients, resulting in an immunologic tolerance/unresponsiveness to MA (IL-2 decreased, IFN-γ unchanged). Finally, increased IL-6 could lead to a perpetuation of immunologic injury through the release of oxygen-free radicals with a cytotoxic effect on the myocardium. We hypothesize an antigen-related, defective macrophage-Th₁ cell reaction, which accounts for the differences in the IL-2 profile between the DCM and HCM groups, that might cause local immune responses to lead to immunosuppression (immune tolerance effect), thus contributing to the pathogenesis of cardiomyopathies.     

Neonatal myasthenia gravis: antigenic specificities of antibodies in sera from mothers and their infants.

Transient neonatal myasthenia gravis (MG) is a human model of passively transferred MG. In an effort to understand the characteristics of the most pathogenic antibodies in MG, we studied the fine antigenic specificities of anti-AChR antibodies in sera from 21 MG mothers (nine of which had transiently transferred the disease) and 17 of their infants. Although in a few cases significant differences in antibody specificities were observed between mothers and infants, whether myasthenic or not, generally the antigenic specificities of the antibodies in sera from infants were very similar to those of their mothers. Furthermore, no characteristic differences were detected between the antibody repertoires of mothers who transferred the disease and those who did not.     

维生素C片剂分解动力学研究

在相对湿度小于临界相对湿度的条件下,在温度为60～90℃、相对湿度为60～80%范围内测定了维生素C片剂的色泽(以相对反射率R表示)变化速率,含量C变化速率及片剂溶液的色泽(以透光率T表示)变化速率。三者的表观速率常数k与热力学温度T和相对湿度RH的关系通式为k=k’exp(-E/RT)exp(mRH),k’和m为常数,E为表观活化能。不同速率常数的k’,m和E值均不同。     

维生素C粉末分解动力学研究

在有氧避光条件下,用恒温恒湿加速试验法,研究了在相对湿度小于临界相对湿度时,维生素C粉末的表观变色速率常数k_c与温度、湿度的关系为:k_c=k′exp(-E_a/RT)exp(m′RH),k′与m′为常数,RH为相对湿度,E_a为活化能。RH<70%时的E_a=104.33 kJ·mol^-1。还研究了在各种相对湿度下维生素C粉末含量变化的曲线方程为:C=N/(1+Btⁿ),速率方程为:k_d为分解反应的表现速率常数,N为原始百分含量,C为时间t的含量,B与n为常数。RH为97,93与79.5%时的E_a分别为86.87,88.22与202.64 kJ·mol^-1。     

以灯光为光源研究药物在自然光照射下的稳定性

介绍了维生素B₂、维生素K₃、磺胺嘧啶锌和维那利酮4种固体药物在自然光及灯光下的稳定性,探讨了不同光源对药物稳定性影响的等效关系。由此可使以不同光源研究药物稳定性所得之结果能相互换算,并可用灯光为光源研究药物在自然光下的稳定性。上述4种药物的表面反射率R与各光源的光照量Et之间的关系都可用经验式R=A+B(Et)十C/(Et+D)准确地表达,并可用本文介绍的方法对不同光源的光照量进行等效换算。