Regional differences in mucosal hemodynamics in experimental colonic injury in rats

In rat colon damaged by 10% acetic acid and by dinitrochlorobenzene, we test the following hypotheses: (1) mucosal hemodynamic changes are significantly different at the ulcer base, the ulcer margin, and the inflamed non-ulcer-bearing mucosa; and (2) these mucosal hemodynamic changes also vary with time after induction of the colonic injury. Mucosal hemodynamic changes were documented by reflectance spectrophotometry, and variations in gross mucosal morphology were confirmed by hematoxylin and eosin histologic sections. Results revealed that in the acute stage, the ulcer base, which was covered by necrotic debris, showed ischemia without congestion. The ulcer margin at the edge of the ulcer base showed ischemia with congestion. The nonulcerated mucosa, which appeared erythematous, showed increased perfusion. In the convalescent stage, all the altered perfusion patterns returned to normal. These observations offer plausible explanations for the variability in colonic perfusion observed in experimentally damaged colons.     

Measurement of stain on extracted teeth using spectrophotometry and digital image analysis

Abstract: Aim: The aim of this study was to assess the reliability and validate a customized image analysis system, designed for use within clinical trials of general dental hygiene and whitening products, for the measurement of stain levels on extracted teeth and to compare it with reflectance spectrophotometry. Method: Twenty non‐carious extracted teeth were soaked in an artificial saliva, brushed for 1 min using an electric toothbrush and a standard toothpaste, bleached using a 5.3% hydrogen peroxide solution and cycled for 6 h daily through a tea solution. CIE L* values were obtained after each treatment step using the customized image analysis system and a reflectance spectrophotometer. A statistical analysis was carried out in SPSS. Results: Fleiss’ coefficient of reliability for intra‐operator repeatability of the image analysis system and spectrophotometry was 0.996 and 0.946 respectively. CIE L* values were consistently higher using the image analysis compared with spectrophotometry, and t‐tests for each treatment step showed significant differences (P < 0.05) for the two methods. Limits of agreement between the methods were ?27.95 to +2.07, with a 95% confidence of the difference calculated as ?14.26 to ?11.84. The combined results for all treatment steps showed a significant difference between the methods for the CIE L* values (P < 0.05). Conclusion: The image analysis system has proven to be a reliable method for assessment of changes in stain level on extracted teeth. The method has been validated against reflectance spectrophotometry. This method may be used for pilot in vitro studies/trials of oral hygiene and whitening products, before expensive in vivo tests are carried out.     

紫外分光光度法测定蜈蚣甘草散中重金属的含量

目的：测定蜈蚣甘草散中重金属的含量。方法：蜈蚣甘草散灰化后用硫化钠显色,用紫外分光光度法测定蜈蚣甘草散中重金属的含量。灰化温度550℃,时间2h;测定条件：pH3．0-3．5,波长202nm。结果：线性范围0-50μg,平均加样回收率为99．52％,RSD1．82％。结论：本方法可靠,稳定性、重现性好,可作为蜈蚣甘草散中重金属限量控制的方法。     

紫外分光光度法测定川射干总黄酮的含量

目的：建立川射干总黄酮含量的测定方法。方法：采用紫外分光光度法测定川射干药材中的射干苷含量,测定波长为266nm。结果：射干苷在0．002-0．010mg·mL^-1范围内与吸光度呈良好的线性关系,r=0．9991,回收率为97．45％,RSD为0．65％,川射干总黄酮的平均含量为4．17％。结论：该方法操作简便、灵敏、准确、具有良好的重复性和回收率,可作为川射干总黄酮含量测定的方法。     

颠胃酸口服液的消化活力测定

目的 建立颠胃酸口服液消化活力测定方法.方法 用酪氨酸为对照品,牛血红蛋白为底物,水浴温度37℃±0.5℃,紫外分光光度法,测定波长275 nm.结果 颠胃酸口服液平均消化活力为33.8μ·mL-1,高于标示量(24μ·mL-1),回收率为98.2％,RSD为0.96％(n=6).结论 该方法用于颠胃酸口服液的消化活力测定,操作便利,试验条件稳定,结果重复性好.     

云南地区大叶千斤拔不同种质的异黄酮含量比较△

目的:建立大叶千斤拔中异黄酮含量测定方法,对比云南不同地区大叶千斤拔的药材质量,初步明确影响异黄酮含量的因素.方法:以染料木素为对照品,对紫外分光光度法测定大叶千斤拔中异黄酮的含量进行方法学考察,并用此方法测定采自云南不同地区野生及栽培的26份大叶千斤拔中异黄酮的含量.结果:采集野生样品中异黄酮的平均含量为0.990‰,其中屏边县的种质含量最高,为1.553‰,而绿春县(B)的种质含量最低,为0.652‰.分别栽培在3个地点的同一份大叶千斤拔种质,异黄酮含量有明显差异;在同一栽培条件下不同来源的大叶千斤拔种质异黄酮含量也有明显差异.结论:种质和环境因子对大叶千斤拔有效成分的积累均有影响.     

Optimising the methodology of calculating the cerebral blood flow of newborn infants from near infra-red spectrophotometry data

Cerebral blood flow can be measured in neonates by near infra-red spectrophotometry. The tracer is oxyhaemoglobin. The purpose of the study is to compare the test-retest variability of two previously proposed methods (UCH and COP) of analysis, and to investigate the influence of sampling rates, smoothing and integration periods. Under clinical conditions good measurements are often difficult to obtain. Therefore, a second goal is to find ways of determining the quality of individual measurements. 380 cerebral blood flow measurements from 69 infants are analysed. The data set is optimised statistically for the lowest test-retest variability and the following results are obtained. The test-retest variability of measurements at 2 s sampling time data is considerably worse than at 0·5 s sampling time. Smoothing does not change the test retest variability. A 6 s integration period gives higher values and higher test-retest variability than an 8 s integration period. By applying the suggested criteria, a test-retest variability of 17% is achieved, if 50% of the measurements are rejected. The mean cerebral blood flow is 12·2 ml(100 g)⁻¹ min⁻¹ for the UCH method and 97·7 ml(100 g)⁻¹ min⁻¹ for the COP method. The test-retest variability of both methods is comparable for 0·5 s sampling time. For 2 s sampling time the method proposed by Skov et al. is significantly better. These test retest variabilities represent maximum values, part of the observed variability may be due to physiological changes of unknown magnitude.     

Accumulation of toxic metals (Pb and Cd) in the sea urchin Diadema aff. antillarum Philippi, 1845, in an oceanic island (Tenerife,Canary Islands)

This document shows the results obtained from a study on the concentration of toxic heavy metals in the internal tissue and exoskeleton of sea urchins, collected from their natural habitat. The levels of lead and cadmium were measured by Graphite Furnace Atomic Absorption Spectrometry. The mean concentrations of lead and cadmium in the internal tissue were 304.04 and 260.54 μg/kg respectively, whereas in the shell they were 185.02 and 142.48 μg/kg. We also performed a statistical analysis of the differences in the distribution of metals between their exoskeleton and their internal content, a correlation study of the metal content in internal tissue and shell and sampling areas, and a correlation study between the metal content and sample size. Since the sea urchin Diadema antillarum presents a wide range of variation in metal content, this study suggests that this species is an excellent bioindicator of heavy metal contamination. © 2009 Wiley Periodicals, Inc. Environ Toxicol, 2010.     

庆大霉素-藻酸钙三维缓释微球的药物释放研究

目的研制庆大霉素一藻酸钙三维缓释微球并调控其庆大霉素的释放。使其达到长期局部抗菌的效果。方法制作不同浓度T、S、U组庆大霉素-藻酸钙缓释凝珠,与庆大霉素-骨水泥颗粒Y组进行庆大霉索释放情况比较。通过不同时间点抽取浸泡液,送紫外分光光度法（UV）及金黄色葡萄球菌（SA）培养检测,由此计算出各组包封率、释放率,绘制庆大霉素释放曲线。结果4组样品（微生物法）的包封率及30d药物释放率分别为：U组（53．99％、36．31％）,S组（39．62％、27．55％）。T组（34．20％、30．83％）,Y组（100．00％、48．49％）。U组的包封率较高,30d释放庆大霉素的总量较大,更接近Y组。4组间差异有统计学意义（P〈0．01）。U、Y组庆大霉素的释放明显高于S、T组的释放。各组30d内庆大霉素的浓度几乎都能超过金黄色葡萄球菌的最低抑菌浓度（MIC）．即〉2μg／mI。结论U组载药缓释凝珠30d内的庆大霉索释放较为理想。可作为BMSCs的三维培养支架。     

紫外分光法测定无花果中苯甲醛

建立了一种简便快速的测无花果中苯甲醛的方法。采用乙醇回流提取，水蒸汽蒸馏挥发分离，在紫外２３０ｎｍ和２４９ｎｍ处双波长测定。测得无花果中苯甲醛含量为５９．６μｇ／ｇ，５次测定变异系数为２．４８％，回收率在８５．６％～９２．５％之间。