High-frequency ventilation (HFV) in hyaline membrane disease —a preliminary report

Eight premature babies affected by hyaline membrane disease and needing mechanical respiratory support were ventilated by means of a VDR 1 (Bird Space Technology) respirator at 10 Hz during a mean time of 51 h. Before HFV 7 infants had been on conventional mechanical ventilation (CMV) and one on nasal CPAP. The values of mean airway pressure (MAP) and oxygenation index (PaO₂/FIO₂) on CMV and HFV were (mean and range): 1. CMV: MAP 15 (4–29) mm Hg, ox. index 15.47 (5.07–23.19) kPa; 2. HFV after 1 h: MAP 15 (10–19) mm Hg, ox. index 24.13 (9.07–46.12) kPa. Improved oxygenation allowed rapid reduction of FIO₂ in the following hours. Only 3 infants were weaned directly from VDR 1, 5 were switched back to CMV mainly because of technical failures of the respirator. The change from HFV to CMV was associated with a fall of PaO₂/FIO₂ from 35.99 (15.86–74.52) to 22.39 (7.33–31.46) kPa. The mean time of artificial ventilation (CMV+HFV) was 121 h (range 46–166). Except for 1 pneumothorax no medical complications were seen during HFV, and all patients survived. Despite impressive improvements in oxygenation it is cautioned against the use of the VDR 1 because of the high incidence of technical problems.     

THE CAIMA SYSTEM

CAIMA is the abbreviation of Computer-Assisted Instant Monitoring drug Administration. CAIMA works on the principle of closed-loop negative feedback. Special programs have been designed to meet the needs of: a) Patients' safety, b) Response level desired, c) Output necessary for actuating the injecting pump. The pump forces the drug solution to enter the body with high precision. The author shows 8-year experience of using CAIMA system in laboratory and in hospital operating rooms. Experimental studies revealed that: CAIMA system attenuates the overshots and undershots usually present in reaction to drug administration, thus saves the drug and thereby causes less side-efiffeets, while the recovery is also much shortened. CAIMA system provides a greater tolerance to extra-stimuli and preserves the body original reactive sensitivity to drug. The homeostasis in animals is better kept with CAIMA than without. Clinically, the arbitrary hypotension during brain surgery with sodium nitroprusside and the control of muscle relaxation in general surgery with muscle relaxants have been successful using CAIMA system.     

亚硝酸钠与AFB1相互作用对遗传物质影响的实验研究

以正常人外周血淋巴细胞的ＳＣＥ率作为细胞遗传学指标，研究了Ｎａ＿２ＳｅＯ＿３与ＡＦＢ＿１相互作用对细胞遗传物质的影响。结果表明，一定浓度的Ｎａ＿２ＳｅＯ＿３（１０￣（－５）ｍｏｌ）对ＡＦＢ＿１所诱发的ＳＣＥ有明显的抑制作用，但当浓度达到１０￣（－２）ｍｏｌ时，细胞增殖受到抑制，到１０￣（－１）ｍｏｌ时细胞出现毒性现象。提示Ｎａ＿２ＳｅＯ＿３具有抑变和细胞毒性双相作用。所以在Ｎａ＿２ＳｅＯ＿３与ＡＦＢ＿１相互作用的ＳＣＥ实验中应避免Ｎａ＿２ＳｅＯ＿３的浓度过高而损伤培养的细胞。     

Short-term indomethacin administration does not impair excretion of acute potassium load in humans

Maintenance treatment with prostaglandin synthesis inhibitors often causes some degree of hyperkalemia, indicating impaired potassium (K) excretion. Hypoaldosteronism probably is a mediating factor, but it is unknown whether these drugs also impair renal K excretion directly. Indomethacin, for example, stimulates NaCl reabsorption in Henle's loop, and thus may impair K excretion by decreasing distal NaCl delivery. We therefore studied the effect of 1 day administration of indomethacin (50 mg tid) on the excretion of a single oral KCl (1 mmol kg-1 body weight) in six healthy volunteers taking a 40 mmol sodium diet. To allow analysis of renal sodium handling, clearance studies were performed during water loading. In this acute setting, indomethacin had no effect on plasma K, and did not decrease plasma aldosterone. However, indomethacin clearly reduced NaCl excretion. Nonetheless, the excretion of the K load was entirely normal. Excretion of the K load was accompanied by increased clearance of phosphate and uric acid, and natriuresis. Data derived from the maximal free water clearance were compatible with increased delivery to and decreased reabsorption from the diluting segment. Occurrence of these effects was not prevented by indomethacin, although overall NaCl excretion remained less than observed without indomethacin. Indomethacin reduced prostaglandin E2 excretion substantially. Apparently, in normal man indomethacin does not impair K excretion directly, even though it greatly reduces NaCl excretion. Moreover, the effects of K on renal NaCl handling, probably contributing to the excretion of a K load, are not dependent on renal prostaglandins.     

尼莫地平片溶出度的研究

采用转篮法对尼莫地平国产市售片，进口片和自制片在不同介质、不同转速和ＰＨ条件下的溶出度进行测试。结果表明，介质对尼莫地平溶出具有很大的影响，而最佳测定方法是以０．１％的十二烷基硫酸钠水溶液为介质，转速１５０ｒ／ｍｉｎ。     

Sodium Valproate-lnduced Cardiovascular Abnormalities in the JchlCR Mouse Fetus

Sodium valproate was administered to Jcl:ICR mice in order to evaluate teratogenicity in the cardiovascular system. A single dose of 600mg/kg of sodium valproate was injected intraperitoneally on gestational day 6, 7, 8 or 9. On day 18 of gestation, dams were laparotomized to observe incidence and type of cardiovascular abnormality in live fetuses. Cardiovascular abnormalities were found most frequently in the group treated on day 7, being recognized in 86% of litters (19/22) and in 29% of live fetuses (70/238). Among these, there were 28 cases of transposition of the great arteries, 13 of double outlet right ventricle, 11 of endocardial cushion defect, 9 of ventricular septal defect, 5 of tricuspid atresia, and 4 of hypoplastic left heart syndrome.     

川芎素对大鼠脑缺血再灌注时突触后致密物质-95活性的影响

应用神经行为学评估、脑梗死容积测量和Western blot分析,探讨研究阿魏酸钠(SF)的神经保护作用及其对局灶性脑缺血损伤时突轴后致密物质-95(PSD-95)活性的影响,证实SF明显改善再灌注24 h神经功能缺陷和减少脑梗死容积,显著增强再灌注后PSD-95表达,表明SF可能通过加强PSD-95活性来改善缺血性损伤.     

Loading anticancer drugs into HDL as well as LDL has little affect on properties of complexes and enhances cytotoxicity to human carcinoma cells

Low density lipoprotein (LDL) has been found to represent a suitable carrier for cytotoxic drugs that may target them to cancer. This study investigated whether very low density lipoprotein (VLDL), LDL and high density lipoprotein (HDL) can be used to effectively incorporate four cytotoxic drugs, 5-fluorouracil (5-FU), 5-iododeoxyuridine (IUdR), doxorubicin (Dox) and vindesine; characterized the complexes; and examined the effect of incorporation on drug cytotoxicity against HeLa cervical and MCF-7 breast carcinoma cells. Significant drug loading was achieved into all three classes of lipoproteins, consistent with the sizes and hydrophobicity of the drugs. The relative loading efficiency was found to be vindesine>IUdR>Dox>5-FU for all three classes of lipoproteins. As shown by electron microscopy (EM), drug incorporation did not affect the size or morphology of the lipoproteins. Differential scanning calorimetry (DSC) showed that drug loading did not significantly change the thermal transition temperature of core lipids in the lipoproteins. The transition enthalpy was changed only for LDL–Dox and LDL–vindesine. The drugs remained stable in the lipoproteins as determined by high performance liquid chromatography (HPLC). EM, DSC and HPLC data suggest that drugs were incorporated into lipoproteins without disrupting their integrity and drugs remained in their stable forms inside lipoproteins. Compared with free drugs in cytotoxicity assays, the IC₅₀ values of LDL– and HDL–drug complexes were significantly lower (2.4- to 8.6-fold for LDL complexes and 2.5- to 23-fold for HDL complexes). All free or lipoprotein-bound drug formulations were comparably more cytotoxic against MCF-7 than HeLa cells. Upregulating the lipoprotein receptors enhanced, and downregulating them inhibited, the cytotoxicity, indicating the mechanistic involvement of lipoprotein receptor pathways. Complexes of all four drugs with VLDL, in contrast to LDL and HDL, had the same cytotoxicity as the four corresponding free drugs. Our results suggest that further studies are required of the potential of HDL to be a cancer targeting drug carrier.     

Low sodium haemodialysis reduces interdialytic fluid consumption but paradoxically increases post-dialysis thirst.

BACKGROUND: Interdialytic weight gain (IDWG) can be reduced by lowering the dialysate sodium concentration ([Na]) in haemodialysis patients. It has been assumed that this is because thirst is reduced, although this has been difficult to prove. We compared thirst patterns in stable haemodialysis patients with high and low IDWG using a novel technique and compared the effect of low sodium dialysis (LSD) with normal sodium dialysis (NSD). METHODS: Eight patients with initial high IDWG and seven with low IDWG completed hourly visual analogue ratings of thirst using a modified palmtop computer during the dialysis day and the interdialytic day. The dialysate [Na] was progressively reduced by up to 5 mmol/l over five treatments. Dialysis continued at the lowest attained [Na] for 2 weeks and the measurements were repeated. The dialysate [Na] then returned to baseline and the process was repeated. RESULTS: Baseline interdialytic day mean thirst was higher than the dialysis day mean for the high IDWG group (49.9+/-14.0 vs 36.2+/-16.6) and higher than the low weight gain group (49.9+/-14.0 vs 34.1+/-14.6). This trend persisted on LSD, but there was a pronounced increase in post-dialysis thirst scores for both groups (high IDWG: 46+/-13 vs 30+/-21; low IDWG: 48+/-24 vs 33+/-18). The high IDWG group demonstrated lower IDWG during LSD than NSD (2.23+/-0.98 vs 2.86+/-0.38 kg; P<0.05). CONCLUSIONS: Our results indicate that patients with high IDWG experience more intense feelings of thirst on the interdialytic day. LSD reduces their IDWG, but paradoxically increases thirst in the immediate post-dialysis period.     

原钒酸钠对Ⅱ型糖尿病的降糖作用研究

目的　观察原钒酸钠对Ⅱ型糖尿病大鼠的降糖作用。方法　用高脂饲料灌胃正常大鼠 ,引起肥胖 ,测定血中游离脂肪酸浓度。同时应用正糖钳技术检测胰岛素抗性 ,对产生胰岛素抵抗的大鼠腹腔注射小剂量链脲菌素 (5 5mg·kg-1) ,然后筛选空腹血糖值大于 11 1mmol·L-1大鼠为糖尿病模型组。连续灌胃原钒酸钠 7d后 ,测定空腹血糖值。结果　①大鼠喂食高脂饲料后 ,正糖钳实验中维持血糖稳态所需胰岛素量增多 ,为 (0 5 4± 0 0 2 )U·min-1,高于正常组 (P <0 0 1) ;同时血中游离脂肪酸浓度增加 ,从正常 (0 4 6 9±0 0 4 7)mmol·L-1至 (1 5 32± 0 2 91)mmol·L-1(P <0 0 1) ;②原钒酸钠对正常大鼠的血糖值无影响 ,而对Ⅱ型糖尿病大鼠的空腹血糖值及糖耐量曲线下面积有降低作用 (P <0 0 5 )。结论　实验结果证明了原钒酸钠可以明显降低Ⅱ型糖尿病大鼠的空腹血糖值 ,并且对糖耐量具有保护作用