Comparison of assays for determination of peptide content for lyophilized thymalfasin*

Abstract: Precise determination of the peptide content in drug substance samples depends highly upon the particular peptide compound and methodology used. Four independent methods were evaluated and compared to determine which would produce the best experimental precision for analysis of thymalfasin (thymosin α‐1). Four different methods were evaluated including elemental analysis (CHN), quantitative amino acid analysis (AAA), high‐performance liquid chromatography (HPLC), and Kjeldahl. This study demonstrates that the AAA method is highly variable in one laboratory while quite precise in another laboratory. Similarly, HPLC results depended on the laboratory conducting the study with more precise values obtained under cGMP. On the contrary, the CHN method yielded highly precise [i.e. <2% coefficient of variation (CV)] values. As precise knowledge of protein content is fundamental for the compounding of final pharmaceutical product of a specific potency, the CHN analysis is recommended for peptide content determination of the drug substance thymalfasin.     

Daily nutrient intake represents a modifiable determinant of nutritional status in chronic haemodialysis patients.

BACKGROUND: In maintenance haemodialysis patients, daily food intake is changeable; however, its relationship with nutritional status is unexplored. This study aimed to evaluate the isolated, long-term effect of daily nutrient intake on nutritional status in haemodialysis patients. METHODS: We performed a prospective 1-year controlled study in 27 chronic haemodialysis patients, without recognized risk factors for malnutrition. Each day for 1 week, four times in the year, we measured protein nitrogen appearance, and assessed dietary protein (DPI) and energy (DEI) intake from dietary diaries. We compared the nutritional outcome of patients spontaneously reducing nutrient intake below the threshold of 0.8 g/kg body weight/day for DPI and 25 kcal/kg body weight/day for DEI during the week (LOW, n = 8), with controls at adequate nutrient intake (CON, n = 19). An interventional 6-month study was then carried out in LOW to verify the cause-effect relationship. RESULTS: All patients showed a day-by-day reduction of whole nutrient intake during interdialytic period, which was mostly relevant in the third interdialytic day (L3). During the 1-year study, even in the presence of adequate dialysis dose and normal inflammatory indexes, body weight (68.0 +/- 5.5 to 65.8 +/- 5.9 kg), serum albumin (3.96 +/- 0.07 to 3.66 +/- 0.06 g/dl) and creatinine (9.2 +/- 1.1 to 8.1 +/- 0.7 mg/dl) significantly decreased in LOW but not in CON. Diaries evidenced in LOW a reduced number of meals at L3 that was explained by the fear of excessive interdialytic weight gain. During the interventional study, daily DPI and DEI increased at L3; this was associated with a significant increment of body weight, and serum albumin and creatinine levels. CONCLUSIONS: In maintenance haemodialysis patients the persistent, marked reduction of daily nutrient intake, even if limited to a single day of the week, is an independent determinant of reversible impairment of nutritional status.     

计算法测定肾小球滤过率的临床应用价值

目的 :探讨采用 WCP公式计算方法测定肾小球滤过率 (GFR)的临床应用价值。方法 :采用 99m Tc DTPA清除率测定 6 6例不同疾病住院患者 GFR(Tc GFR) ,并测血清肌酐 (SCr)及尿素氮 (BU N) ,同时以 WCP公式、Robert公式计算 GFR(WCP GFR,Robert GFR) ,以 Cockcroft/ Gault公式计算内生肌酐清除率 (CG CCr) ,所得数据进行对比研究及相关性分析。结果 :除肾功能正常者 CG CCr与 BU N无显著相关外 ,肾功能不全及肾功能正常者的 WCP GFR、Robert GFR、CG CCr均分别与 Tc GFR呈显著正相关(P均 <0 .0 1) ,与 BU N、SCr呈显著负相关 (P<0 .0 1或 P<0 .0 5 ) ;与 Robert GFR、CG CCr比较 ,WCPGFR始终与 Tc GFR最接近 (P均 >0 .0 5 ) ;WCP GFR、Robert GFR、CG CCr与 Tc GFR的平均差绝对值逐渐增大 ,三者间差异显著 (P均 <0 .0 5 )。结论 :WCP GFR、Robert GFR、CG CCr均能在一定程度上准确反映 GFR,而以 WCP GFR更准确 ,且简便、快速、安全而廉价 ,可代替 Tc GFR应用于临床     

Clinical experience with minimal flow xenon anesthesia

Xenon is a more potent anesthetic than nitrous oxide, and gives more profound analgesia. This investigation was performed to assess the potential of xenon for becoming an anesthetic inspite of its high manufacturing cost. Seven ASA I—-II patients undergoing cholecystectomy (n = 4), hernia repair (n = 2), or mammoplasty (n=l) were studied. Denitrogenation by 15–20 min of oxygen breathing under propofol anesthesia was followed by fentanyl–supplemented xenon anesthesia administered via an automatic minimal flow system which held the oxygen concentration at 30%. Xenon anesthesia lasted 76–228 min and 8–14 1 of xenon (ATPD) was used, of which 5.6–8.1 1 was expended during the first 15 min. Anesthesia appeared to be satisfactory, and the patients woke up rapidly after xenon was discontinued. The automatic system made minimal flow xenon anesthesia easy to administer, but nitrogen accumulation is still a problem. Assuming a xenon price of 10 US $ per litre, the average cost for xenon was about 65 US $ for the first 15 min and then about 25 USS for each subsequent hour of anesthesia.     

有机氮源对红霉素发酵影响的具体分析

红色糖多孢菌的摇瓶培养基中使用不同有机氮源时红霉素的效价明显不同。通过对不同有机氮源所含营养成分的逐步回归分析,我们得到有机氮源中的苏氨酸为影响红霉素效价的主要因子。最后向对照培养基中添加苏氨酸,则使红霉素的效价比对照培养基提高了22.85%。     

Gaseous homeostasis during low-flow anaesthesia

The object of this clinical study was to investigate the circle system gas homeostasis during low-flow anaesthesia using a technique designed to keep a constant inspired oxygen fraction of 0.30. Denitrogenation was adequately accomplished with mask preoxygenation, 10 l/min, for 1 min and an initial fresh gas flow of 5 l/min for 6 min after intubation. There was no need to wash out accumulated nitrogen at intervals, since the already low nitrogen concentration in the system tended to decrease after 1 h. The fresh gas flow of nitrous oxide to oxygen ratio and the inspiratory to end-expiratory oxygen concentration difference both reflected the uptake of nitrous oxide. The calculated rates of uptake of nitrous oxide, a subject of controversy, were in accordance with those found by Severinghaus and Barton & Nunn.     

深圳宝安3～7岁健康幼儿血清糖、离子、非蛋白含氮类化合物表达水平观察

目的观察深圳宝安3～7岁健康幼儿血清糖、离子、非蛋白含氮类化合物表达水平。方法采用OLRPUSAU-640全自动生化仪及OLRPUS诊断试剂、东欧生物诊断试荆，检测316例体检健康幼儿血清中Ca^＋＋、Mg^＋＋、P^＋＋＋、GLU、BUN、Cr、UA的含量。结果①．1组与4组及2组与3、4组Ca^＋＋组间方差分析，差异有统计学意义，P〈0.05。②．1组与2、3、4组Cr组间方差分析，差异有统计学意义P〈0．05。而Mg^＋＋、P^＋＋＋、GLU、BUN、UA组间方差分析差异无统计学意义，P〉0．05。结论笔者证实了3～4岁健康幼儿与6～7岁健康幼儿及4～5岁健康幼儿与5～7岁健康幼儿血清Ca^＋＋表达水平有差异。也证实了3～4岁健康幼儿与4～7健康幼儿Cr含量存在差异。由此可见，3～7岁健康幼儿建立自己的参考值是必要的。     

人工家蚕蛹巴西虫草的毒性研究

对人工家蚕蛹巴西虫草的毒性进行了研究。结果表明：小鼠和大鼠经口ＬＤ５０分别为＞４３．０ｇ／ｋｇ和＞５０ｇ／ｋｇ。３０天喂养试验中大鼠食欲下降，体重增长减慢；血清胆固醇和血清尿素氮浓度降低，血清总蛋白和血糖无改变；血尿常规无异常；心、肝、牌等脏器系数无改变；肝、肾组织病理学检查未发现明显改变。可认为该产品无明显急性和亚急性毒性。     

急性冠周炎患者冷疗前后的免疫状态研究

本文采用液氮浅低温冷冻疗法治疗５０例急性冠周炎患者，取得了良好临床效果，并于冷疗前后对血及唾液中ＩｇＧ、ＩｇＡ、ＩｇＭ和血中Ｃ３及淋巴细胞转化率进行了免疫状态研究。实验结果表明，冷疗后系列免疫指标明显增高。故认为冷冻治疗冠周炎的主要机理是提高机体的免疫功能。