THE GASTROINTESTINAL ABSORPTION OF PENICILLIN V IN CHILDREN WITH SUSPECTED COELIAC DISEASE

Abstract. The gastrointestinal absorption of penicillin V (pc-V) was investigated in 6 children, 6–12 months old, with suspected coeliac disease. The diagnosis was set after small bowel biopsy and absorption tests of vitamin A and d -xylose. As control groups served 7 children with diarrhoea but with normal small bowel biopsy and/or absorption tests and a group of 9 children with upper respiratory tract infection of the same ages as the children in the test group. The absorption of calcium pc-V in oil suspension (Penicals®) was impaired in the patients with suspected coeliac disease compared to that of the control groups. There was no significantly different absorption of pc-V between the control children with diarrhoea and those with upper respiratory tract infection. After 6–8 months of gluten free diet in the children with suspected coeliac disease their absorptive ability of oral calcium pc-V in suspension form was equal with that of a control group.     

Evaluation of specific absorption rate as a dosimeter of MRI-related implant heating

PURPOSE: To compare the magnetic resonance imaging (MRI)-related heating per unit of whole body averaged specific absorption rate (SAR) of a conductive implant exposed to two different 1.5-Tesla/64 MHz MR systems. MATERIALS AND METHODS: Temperature changes at the electrode contacts of a deep brain stimulation lead were measured using fluoroptic thermometry. The leads were placed in a typical surgical implant configuration within a gel-filled phantom of the human head and torso. MRI was performed using two different transmit/receive body coils on two different generation 1.5-Tesla MR systems from the same manufacturer. Temperature changes were normalized to whole body averaged SAR values and compared between the two scanners. RESULTS: Depending on the landmark location, the normalized temperature change for the implant was significantly higher on one MR system compared to the other (P < 0.001). CONCLUSION: The findings revealed marked differences across two MR systems in the level of radiofrequency (RF)-induced temperature changes per unit of whole body SAR for a conductive implant. Thus, these data suggest that using SAR to guide MR safety recommendations for neurostimulation systems or other similar implants across different MR systems is unreliable and, therefore, potentially dangerous. Better, more universal, measures are required in order to ensure patient safety.     

Human enamel dissolution in citric acid as a function of pH in the range 2.30< or =pH< or =6.30--a nanoindentation study

The objective of this study was to investigate the dissolution of human enamel in citric acid solutions over a wide range of pH. The in vitro conditions are considered to be relevant to soft drink-induced enamel erosion. Nanoindentation was used to investigate changes in the nanomechanical properties of polished enamel surfaces after exposure to citric acid solutions. Solutions used had 38.1 mmol l-1 citric acid and pH greater than 2.3 but less than 6.3 (2.30 < or = pH < or = 6.30). Samples were exposed to rapidly stirred, constant composition solutions for 120 s. Statistically significant changes in enamel hardness and reduced elastic modulus were observed after exposure to all solutions. There was an approximately linear dependence of enamel hardness on solution pH for 2.90 < or = pH < or = 6.30. Below pH 2.90, enamel is thought to have reached the lowest possible hardness value. The reduction in enamel dissolution caused by an increase in pH of a soft drink is likely to be small. Product modification to reduce the erosive potential of drinks may require additional methods such as addition of calcium salts.     

The role of fetal breathing motions compared with gasping motions in pulmonary airway uptake of intra-amniotic iron dextran

OBJECTIVE: We hypothesized that normal fetal breathing, not acute asphyxial gasping, results in the movement of iron dextran from the amniotic cavity into the fetal lungs. In addition, the amount of iron dextran moving into the fetal lungs is cumulative with time. STUDY DESIGN: Twelve pregnant New Zealand White rabbits at 25 days of gestation were sedated and underwent ultrasound-guided injections of iron dextran into the amniotic cavities of the rabbit fetuses in both horns of each pregnant doe. Oxygen saturation was maintained at >90% in the pregnant does. The 12 does were then equally assigned to four groups on the basis of the duration of fetal exposure to the dextran (0, 8, 16, and 24 hours). At the end of each time point, one half of the fetuses received an intracardiac injection of potassium chloride to induce gasping just before necropsy. Gasping was confirmed by ultrasound scanning. At necropsy, the fetal lungs were evaluated grossly and underwent histomorphometry for iron distribution and quantification in the fetal airways. RESULTS: In the animals that received iron dextran, there was no significant difference in iron accumulation at any time point between those animals that did and did not receive potassium chloride, which suggests that acute gasping does not increase the accumulation of amniotic fluid substances in the lungs. The amount of iron in the fetal airways increased significantly with progressive length of exposure. CONCLUSION: We conclude that normal fetal breathing, not acute asphyxial gasping, resulted in the movement of intra-amniotic iron dextran into the fetal lungs and that the amount of substances that move into the fetal lungs accumulated with time.     

Effect of chronic Li+ treatment on free intracellular Mg2+ in human neuroblastoma SH-SY5Y cells

Objectives:  Previous findings have demonstrated Li⁺/Mg²⁺ competition at therapeutic intracellular Li⁺ levels after acute Li⁺ treatment in human neuroblastoma SH-SY5Y cells. In the current study, we examined whether Li⁺/Mg²⁺ competition exists at therapeutically relevant extra- and intracellular [Li⁺] after chronic Li⁺ loading times.
Methods:  In human neuroblastoma cells, intracellular free Mg²⁺ was determined by fluorescence spectroscopy with the fluorophore furaptra. Intracellular Li⁺ and Mg²⁺ were measured by atomic absorption spectrophotometry.
Results:  After loading of the neuroblastoma cells with 1–2 mM extracellular Li⁺ for 24–72 h, the observed, increased intracellular free [Mg²⁺] levels were significantly higher (p < 0.03) than those in matched Li⁺ free cells, and intracellular [Li⁺] was found to be at therapeutic intracellular levels (0.7–1.5 mM).
Conclusions:  The results demonstrate that Li⁺/Mg²⁺ competition exists after chronic treatment with Li⁺ at therapeutically relevant intracellular Li⁺ levels in neuroblastoma cells. We found differences between acute and chronic Li⁺ treatment effects on the extent of Li⁺/Mg²⁺ competition. Possible reasons for these differences are discussed.     

63Ni-NiCl2在大鼠体内的药代动力学及其组织残留

镍是动物体必需的微量元素,参与核酸和蛋白质的代谢、激素的调节过程,具有刺激生血、促进红细胞再生的功能[1],与激素、蛋白质和脂类的代谢也密切相关.国内相关研究较少,尤其使用同位素标记法研究更少.     

阿托伐他汀对兔动脉粥样硬化血管内皮细胞膜超微结构影响的研究

目的探讨纳米水平上阿托伐他汀对兔动脉粥样硬化(atherosclerosis,AS)血管内皮细胞(vascular endothelial cell,VEC)超微结构的影响。方法44只♂新西兰大白兔,随机分为3组,对照组12只,高脂组16只,阿托伐他汀组16只,分别于2、6wk末随机抽取6~8只处死,采血检测血脂,取胸主动脉制作标本,应用原子力显微镜(atomic force micro-scope,AFM)观察。结果AFM50μm大范围扫描可见对照组VEC呈梭形,大小约11.96μm×3.72μm。排列规则,其长轴与血流方向一致;高脂组2、6wk末兔VEC较正常对照组明显变大肿胀,变形,排列紊乱。500nm超微结构扫描正常组细胞膜蛋白由圆形、椭圆形的隆起构成,大小基本一致,隆起光滑饱满,隆起间界线分明;2、6wk高脂组内皮细胞膜蛋白由许多大小不一的隆起构成,形态各异,隆起表面凹凸不平,隆起间有许多孔洞,隆起间界限模糊;阿托伐他汀组2、6wk末VEC超微结构明显改善,更接近正常对照组。同时比较了3组500nm水平下膜蛋白的平均粗糙度(mean roughness,Ra),发现在2、6wk高脂组明显高于正常对照组和药物组,差异具有统计学意义(P<0.01),阿托伐他汀组细胞膜粗糙度高于正常对照组(P<0.01)。结论AFM可直观的观察到AS受损的VEC及细胞膜的超微结构改变,以及阿托伐他汀明显改善AS引起的VEC损伤,从而发挥其降脂外的抗AS作用。     

In vitro release studies of chlorpheniramine maleate from gels prepared by different cellulose derivatives

The objective of this study was to evaluate the in vitro and ex vivo percutaneous absorption of chlorpheniramine maleate (CPM) from different hydrogel formulations. Various concentrations of polymers, including hydroxypropylmethylcellulose (HPMC), sodium carboxymethylcellulose (NaCMC) and methyl cellulose (MC) were used in the hydrogel formulations. All experiments were conducted using cellulose dialysis membrane. The passive permeation of CPM was affected by the polymer concentrations. The effect of each polymer on the release rate of CPM was found to be statistically different (P<0.05). The formulation which exhibited maximum drug release through cellulose membrane was then used with other membranes namely polyurethane membrane, rat skin and human skin. The release rate of CPM from different membranes was found to be statistically different (P<0.05). Within the different diffusional barriers rat skin was found to be best alternative to human skin. It seems suitable the use of cellulose derivatives for topical application of CPM to obtain high therapeutic concentration at the application site. The synthetic membranes can be used to assess product performance in quality assurance but give little indication of its performance ex vivo.     

人胃腺癌组织的吸收系数光谱和散射系数光谱特性

目的探讨人胃腺癌组织的光谱特性。方法测定26个人胃腺癌标本的肿瘤及非肿瘤区域组织的吸收系数光谱和散射系数光谱。结果人胃腺癌组织吸收系数在300～720nm光谱范围内明显低于非肿瘤胃壁组织，散射系数在480～1100nm光谱范围内也明显低于非肿瘤胃壁组织。结论胃腺癌组织和非肿瘤胃壁组织的吸收系数光谱和散射系数光谱差异有统计学意义，为进一步研究提供有意义的参考数据。