HPLC测定九分散中麻黄碱、伪麻黄碱和士的宁的含量

本文用HPLC法对中成药九分散中麻黄碱、伪麻黄碱及士的宁进行了分离及含量测定。与药典法比较,本法的提取率较高,其中麻黄碱为药典方法的1.33倍,伪麻黄碱为1.29倍,而士的宁则与药典方法相当。在μBondapak C_(18)色谱柱上,用MeOH—KH_2PO_4溶液为流动相梯度洗脱进行了各组分的分离。各组分工作曲线线性良好,麻黄碱,伪麻黄碱在0～8μg、士的宁0～14μg范围内呈线性关系。测得回收率为麻黄碱98.94±2.2%;伪麻黄碱97.37±1.9%;士的宁100.7±1.9%。     

Posterior atlantooccipital subluxation in Down syndrome

Three Down syndrome patients with posterior atlantooccipital (AO) subluxation are described. All are asymptomatic. The subluxation becomes manifest during active extension of the neck and reduces in flexion. Methods of assessing posterior AO subluxation are discussed. The abnormality is attributed to ligamentous laxity in patients with Down syndrome.     

Ten-Years Follow-Up of 20 Patients with Idiopathic Ventricular Tachycardia

The follow-up and characteristics of 20 patients with ventricular tachycardia (VT) and no detectable heart disease is reported. These were 16 men and four women with a mean age of 44 years. Symptoms were present in 18 patients (eight had syncope and ten palpitations or dizziness), VT was sustained in 11 patients and a left bundle branch block morphology with inferior axis was found in 17 patients. In three patients, VT had a right bundle branch block morphology and left-axis deviation. The VT was inducible in 13 patients during the electrophysiological testing (EP) and was sustained in five patients. Medical treatment was introduced in 19 patients. During a mean follow-up of 10 years from the onset of the symptoms and 6 years from the EP testing, one patient died suddenly. He had stopped taking amiodarone 5 months before. In seven patients symptoms recurred and were due to discontinuation of therapy in two cases and inefficacy of previous effective treatment in five patients. After modification of the treatment (three cases), implantation of a pacemaker (one case) and catheter ablation (one case), all patients became asymptomatic. Eleven patients became asymptomatic with the first administered antiarrhythmic therapy. One patient continues to be asymptomatic in spite of discontinuation of his medical therapy. We conclude that patients with VT and no detectable heart disease have a good long-term prognosis and that appropriate therapy can be found in almost all patients.     

Recombinant human factor IX: replacement therapy, prophylaxis, and pharmacokinetics in canine hemophilia B

Recombinant human factor IX (rFIX) has been expressed in transduced cultured cell systems since 1985. Because there has been limited in vivo testing of rFIX in hemophilia B subjects, this study was undertaken using the severe hemophilia B canines of the Chapel Hill strain. Three groups of hemophilic dogs received either 50, 100, or 200 IU/kg of rFIX. As a control, a fourth group of hemophilic dogs received 50 IU/kg of a high purity, plasma-derived human FIX (pdFIX). The coagulant and hemostatic effects of rFIX and pdFIX were similar with all comparative dosing regimens. Based on activity data, the elimination half-life of rFIX was 18.9 +/- 2.3 hours and pdFIX was 17.9 +/- 2.1 hours. A prophylactic regimen administering rFIX daily resulted in a continuous therapeutic level of plasma FIX and was accompanied by a two-fold increase in recovery levels by day 5, compared to that observed with administration of a single bolus. The mechanisms of the high to complete recovery of FIX with the prophylactic regimen could depend not only on the degree of saturation of the vascular endothelial binding sites but also on the altered dynamics of the balance of FIX distribution between the intravascular and extravascular compartments. The pharmacokinetic (PK) parameters for rFIX and pdFIX were similar. However, the relative PK values for V1 and V5s of both products on day 5 differed greatly from day 1 and may reflect the changing equilibrium of FIX between compartments with elevated levels of plasma FIX. Neutralizing antihuman FIX antibodies resulting from human FIX antigen being administered to FIX deficient dogs were observed beginning at 14 days. The antigenicity of rFIX and pdFIX appeared to be comparable. Despite the very different procedures used for production of rFIX and pdFIX products, in vivo testing in hemophilia B dogs showed the functional behavior of these products is similar; they are highly effective for replacement therapy and for prophylaxis.     

The mechanism of thrombin-induced platelet factor 4 secretion

We have measured thrombin-induced secretion of platelet factor 4 antigen (PF4) and simultaneously followed its intracellular translocation by immunofluorescence. In permeable resting platelets, speckled intracellular immunofluorescent staining for PF4 was observed. Addition of thrombin to washed platelets at 22 degrees C resulted in secretion of PF4 and formation of large (approximately 0.5 micrometer) immunofluorescent masses. These masses moved to the cell periphery during secretion and were virtually absent at the conclusion of secretion. Ultrastructural examination of thrombin-treated platelets revealed vacuoles corresponding in size, shape, and time of occurrence to the large immunofluorescent masses of PF4. These vacuoles contained PF4 by immunoferritin staining of frozen thin sections; they therefore appear to represent the ultrastructural counterpart of the large PF4 masses. When intact cells were stained for PF4 after thrombin addition, only 5.6% of the large masses stained. Thus, during secretion, PF4 antigen is consolidated into large closed pools that appear as vacuoles in the electron microscope.