肉制品中亚硝酸盐含量催化比色测定

本文根据亚硝酸根在酸性条件下能促进氯酸钾氧化考马斯亮蓝G反应,建立了肉制品中亚硝盐含量测定新方法。最大吸收峰590nm,线性范围0～0.50×10~(-5),回收率94～109％。     

Preoperative prediction of postoperative visual acuity in patients with cataracts: A quantitative review

Many tests of visual function have been proposed as means of preoperatively evaluating cataract patients' surgical outcomes. It is impractical to compare all of these tests simultaneously on the same group of patients. Quantitative reviews apply quantitative methods to comparisons across studies. We compared the results of 52 reports in which cataract patients' postoperative acuity was predicted by means of visually evoked potential, laser interferometry, or projection tests (potential acuity meters-pinhole). The results of each study were summarized in a 2 × 2 contingency table. Summary statistics were compared by means of analysis of variance and post hoc tests. Despite difficulties in metaanalysis, we found the visually evoked potential a better predictor with dense opacities. We recommend standardization in a quest for more precise predictions of postoperative visual acuity.     

0.5%亚甲蓝复合液治疗带状疱疹性神经痛

目的观察带状疱疹急性期疼痛采用亚甲蓝复合液施行神经阻滞的镇痛效果。方法在疱疹的神经支配区域进行椎旁神经阻滞和肋间神经阻滞，阻滞药物为0．5％亚甲蓝复合液，内含布比卡因和VitB12。结果全组31例注药后VAS评分均降至1．5以下，镇痛持续72～80h，半年～1年疼痛无复发。结论应用亚甲蓝复合液治疗带状疱疹神经痛，止痛效果确切且持久。     

Can in-vitro assays predict chemically-induced skin damage?

Eleven chemicals with a known potential to damage skin as corrosive, irritants or non-irritants, have been tested for their ability to affect the function and viability of mammalian cells in three in vitro assays. The assays measured total protein content by Coomassie Blue R binding (CB), lysosomal integrity by Neutral Red uptake (NR), or mitochondrial function by MTT uptake/reduction. Two cell lines, Chinese Hamster Ovary cells (CHO) and Swiss Albino Mouse Fibroblasts (3T3), were compared. The results of all three assays agreed well with one another and with the observed number and morphology of the cells for each chemical tested. The CB tended to be the least sensitive and the NR the most variable of the three assays. Overall the MTT assay was most reliable, but may give anomalous results if used alone. CHO and 3T3 cells gave similar results, although 3T3 cells tended to be less sensitive than CHO cells. This may depend principally on the rate of division and proportion of dividing cells. Using the results from the MTT assay, corrosive chemicals were cytotoxic, since concentrations of less than 10 μg/ml reduced dye uptake by 50%. Chemicals which were skin irritants were moderately cytotoxic, since concentrations in the order of 50–500 μg/ml reduced dye uptake by 50%. Non-irritant chemicals were not cytotoxic up to 5 mg/ml. In decreasing order of cytotoxicity, the chemicals were ranked: tributyltin chloride, dibutyltin dichloride, silver nitrate, benzalkonium chloride, zinc monoglycerolate, sodium dodecyl sulphate, benoxaprofen, fenclofenac, n-hexane, butan-1-ol, 2-methoxyethanol. The categorization and ranking of the degree of skin irritation concurred with the degree of cell kill. These results indicate that such simple in-vitro tests could be used instead of animals to predict skin irritants at an early stage of hazard identification.     

Methylene blue increases systemic vascular resistance in human septic shock

We report the hemodynamic improvements induced by intravenous methylene blue (MB), a guanylate cyclase inhibitor, in 2 patients with hyperdynamic septic shock treated with norepinephrine (NE) infusion, mechanical ventilation an hemodialysis. MB injection augmented the low vascular resistance, mean arterial pressure and induced a slight decrease of cardiac index, without any change of heart rate and pulmonary artery wedge pressure. Plasma cyclic GMP levels decreased without a significant change of atrial natriuretic factor levels. MB (2 mg·kg^–1) induced a longer lasting improvement of circulatory failure without deleterious side effects, but did not prevent the occurrence of delayed multiorgan failure or subsequent death. These data suggest that in patients, severe sepsis-induced loss of vascular responsiveness to NE involves activation of soluble guanylate cyclase, possibly stimulated by enhanced nitric oxide production. Furthermore, these observations support the concept that pharmacological blockade of guanylate cyclase may improve hemodynamics but not survival rates.     

考马斯亮兰G—250染料测定蛋白质方法的改进

考马斯亮兰G-250(简称G-250)酸性溶液呈红棕色,与蛋白质结合时变为兰色,A_(max)从465nm移至595nm。在一定条件下,蛋白质浓度与A_(595nm)成正比,据此作蛋白质定量。本法有快速、简便、灵敏和抗多种化学试剂干扰等优点,已得到广泛使用。但此法对不同的蛋白质定量有时差异较大,并时有不稳定的染料蛋白复合物沉出,影响测定准确度~4。作行用正交试验法选出了试剂配制的最佳条件,对经典法作了改进。     

Methylene blue inhibits stimulatory effect of sodium nitroprusside but not of 3-morpholino sydnonimine on prolactin secretion in freely moving male rats

Previously we reported that intracerebroventricular (i.c.v.) administration of nitric oxide (NO) donors, sodium nitroprusside (SNP) (1–10 μg), and 3-morpholino-sydnonimine (SIN-1) (10–100 μg), induced dose-dependent increases in plasma prolactin levels of freely moving male rats, suggesting a role of NO in the control of prolactin secretion. The present results show that i.c.v. pretreatment with methylene blue (MB) (30 μg), a guanylyl cyclase inhibitor, significantly reduced the effects of microinjections of SNP (3 and 5 μg), however, this did not modify the stimulatory action of SIN-1 (30 μg) on plasma prolactin levels of conscious male rats. Alone, MB did not modify basal prolactin levels. These results suggest different mechanisms of action of SNP and SIN-1 to stimulate prolactin secretion in vivo. Activation of soluble guanylyl cyclase seems to mediate the neuroendocrine action of NO released from SNP but not of SIN-1. Different cellular distribution of NO generating activity from these donors as well as the possible generation of other radicals simultaneously with NO from SIN-1 could explain these differences.     

油脂中阴离子表面活性剂残余含量的测定

在氯仿溶液中 ,十二烷基硫酸钠和亚甲基蓝发生络合反应生成一定的络合物 ,通过测定络合物的吸光度可计算十二烷基硫酸钠的含量 .用此法可测定表面活性剂分提猪油后在产品中的残余含量 ,具有操作简单、结果准确等优点 ,适合工业生产中使用