BACKGROUND & AIMS: :We investigated the suppressive effects of phosphate on calcium determinations with lanthanum-air/acetylene and potassium-nitrous oxide/acetylene methods, and we evaluated the ability of these methods to meet the suggested analytical goals for urine samples. The 20 g/L La-air/acetylene method was the most nearly accurate for predicting the actual calcium concentrations (t-test value = -0.042), followed by the 2 g/L K-nitrous oxide/acetylene method (t-test value = 0.450), 10 g/L La-air/acetylene (t-test value = -0.733), and finally 5 g/L La-air/acetylene (t-test value = -2.446). The dilution used significantly influences the apparent calcium concentration measured with the La-air/acetylene methods.

背景与目标： ：我们研究了镧-空气/乙炔和亚硝酸钾钾/乙炔方法对磷酸盐测定钙的抑制作用，并评估了这些方法满足尿液样品建议分析目标的能力。 20 g / L La-air /乙炔法最准确地预测实际钙浓度（t-检验值= -0.042），其次是2 g / L K-一氧化二氮/乙炔法（t检验）值= 0.450），10 g / L La-空气/乙炔（t-检验值= -0.733），最后是5 g / L La-空气/乙炔（t-检验值= -2.446）。使用的稀释液会显着影响用La-air /乙炔法测得的表观钙浓度。

BACKGROUND & AIMS: :Two approaches have been adopted to increase the steepness of the slopes and the sharpness of the curvature of an absorption curve in the visible region. These are recording (i) A (1cm) versus log wavelength or (ii) A (1cm) versus wavenumber. The computer program was tested by calculating the ratios of the first derivative optima for a Gaussian band, and proved that changing wavelength into log wavelength or wavenumber is effective to squeeze an absorption curve non-linearly. Spectrophotometric identification of cyanocobalamin in the visible region was carried out using the ratios (Delta D1/D2) calculated for lambda, log lambda and nu scales. The ratios were highly reproducible and independent of concentration. First, second and fourth-order derivative determination of cyanocobalamin in injection solutions was performed in the visible region at 20040.08, 17452.01, (20040.08 - 17452.01) cm(-1) for D11(nu), D12(nu) Delta D1 (D11-D12) (nu), respectively, and at 18018.02 cm(-1) for D2(nu) and D4(nu).

背景与目标： ：已采用两种方法来增加可见区域中的斜率的陡度和吸收曲线的曲率的锐度。这些记录的是（i）A（1cm）对数波长或（ii）A（1cm）对波数。通过计算高斯带的一阶导数最优值的比率对计算机程序进行了测试，并证明了将波长更改为对数波长或波数可以有效地非线性地压缩吸收曲线。使用计算λ，对数λ和nu比例的比率（ΔD1 / D2）进行可见光区氰钴胺的分光光度鉴定。该比率是高度可再现的，并且与浓度无关。对于D11（nu），D12（nu）Delta D1（D11- D12）（nu），对于D2（nu）和D4（nu）分别为18018.02 cm（-1）。

BACKGROUND & AIMS: :The present study reports on the application of modified groundnut shell as a new, easily prepared, and stable sorbent for the extraction of trace amount of Cr(III) in aqueous solution. 2-Hydroxybenzaldiminoglycine was immobilized on groundnut shells in alkaline medium and then used as a solid phase for the column preconcentration of Cr(III). The elution was carried out with 3 mL of 2 mol L(-1) HCl. The amount of eluted Cr(III) was determined by spectrophotometry using cefaclor as a complexing reagent and by flame atomic absorption spectrometry (FAAS). Different experimental variables such as pH, amount of solid sorbent, volume and concentration of eluent, sample and eluent flow rate, and interference of other metal ions on the retention of Cr(III) were studied. Under the optimized conditions, the calibration curves were found to be linear over the concentration range of 13-104 and 10-75 μg L(-1) with a detection limit of 3.64 and 1.24 μg L(-1) for spectrophotometric method and FAAS, respectively. An enrichment factor of 200 and RSD of ±1.19-1.49 % for five successive determinations of 25 μg L(-1) were achieved. The column preconcentration was successfully applied to the analysis of tap water and underground water samples.

背景与目标： ：本研究报道了改性花生壳作为一种新型，易于制备且稳定的吸附剂在萃取水溶液中痕量Cr（III）中的应用。将2-羟基苯扎尔二氨基甘氨酸固定在碱性介质中的花生壳上，然后用作固相用于Cr（III）的柱预浓缩。用3 mL 2 mol L（-1）HCl进行洗脱。 Cr（III）的洗脱量通过使用头孢克洛作为络合剂的分光光度法和火焰原子吸收光谱法（FAAS）确定。研究了不同的实验变量，例如pH，固体吸附剂的量，洗脱液的体积和浓度，样品和洗脱液的流速以及其他金属离子对Cr（III）保留的干扰。在优化的条件下，发现校正曲线在13-104和10-75μgL（-1）的浓度范围内是线性的，分光光度法和FAAS的检出限为3.64和1.24μgL（-1）。 ， 分别。连续5次测定25μgL（-1）的富集系数为200，相对标准偏差为±1.19-1.49％。柱预浓缩成功地用于自来水和地下水样品的分析。

BACKGROUND & AIMS: :This study assesses the incidence, histogenesis, and significance of eccrine sweat duct involvement in Bowen's disease (BD). In a review of 96 cases of BD, four showed eccrine duct involvement on hematoxylin and eosin-stained histologic sections. One case was analyzed for deoxyribonucleic acid (DNA) ploidy by using computerized image analysis on Feulgen-stained slides. Sections were also stained immunohistochemically, using antibodies to carcinoembryonic antigen (CEA), gross cystic disease fluid protein (GCDFP), and S-100 protein, and for cytokeratins (CAM 5.2, AE 1/3). Our results showed that, in BD, (a) the eccrine sweat ducts can be extensively involved by atypical cells, (b) the atypical eccrine duct cells had an aneuploid DNA pattern, and (c) the atypical eccrine duct cells were negative for CEA, GCDFP, and S-100 protein but were positive for cytokeratins. We conclude that (a) the frequency of eccrine duct involvement in BD is relatively low (approximately 4 to 9%), (b) the aneuploid DNA pattern makes a benign squamous metaplasia unlikely, (c) the immunohistochemical results exclude coincidental Paget's disease or carcinoma of eccrine sweat glands, (d) the involvement of eccrine sweat ducts may represent a direct extension of the neoplastic epidermal keratinocytes, and (e) this process may have practical implications in the recurrence of superficially treated cases of BD.

背景与目标： ：本研究评估了鲍文氏病（BD）中内分泌汗管受累的发生率，组织发生和意义。在对96例BD病例的回顾中，有4例显示苏木精和曙红染色的组织切片受累于内分泌管。通过对Feulgen染色载玻片进行计算机图像分析，对一例进行了脱氧核糖核酸（DNA）倍性分析。还使用抗癌胚抗原（CEA），总胆囊疾病液蛋白（GCDFP）和S-100蛋白以及细胞角蛋白（CAM 5.2，AE 1/3）的抗体对切片进行免疫组织化学染色。我们的研究结果表明，在BD中，（a）非典型分泌管可广泛参与非典型分泌管的分泌汗管，（b）非典型分泌管具有非整倍体DNA模式，（c）非典型分泌管对CEA呈阴性，GCDFP和S-100蛋白，但细胞角蛋白呈阳性。我们得出的结论是：（a）BD内分泌管受累的频率相对较低（约4％至9％），（b）非整倍体DNA模式使得良性鳞状化生不太可能，（c）免疫组织化学结果排除了巧合的Paget病或内分泌汗腺癌；（d）内分泌汗管受累可能代表赘生性表皮角质形成细胞的直接延伸；（e）此过程可能对表面治疗的BD病例的复发具有实际意义。

BACKGROUND & AIMS: :We describe a method for determining plasma and erythrocyte lithium concentrations by atomic absorption spectrophotometry. Plasma and hemolyzed whole-blood are diluted and analyzed, with use of a lithium hollow-cathode lamp, at 670.8 nm. Erythrocyte lithium concentrations are calculated indirectly from the hematocrit. The standard deviation for a 0.43 mmol/liter pool of whole blood, run daily over 11 months, was +/-20 mumol/liter (CV=5.1). The lithium concentration of a lyophilized pool assayed periodically over the same period (n=127) was 1.84+/-0.05 mmol/liter (CV=2.7%). The relatively low erythrocyte/plasma lithium ratio and the microhematocrit centrifugation force (9600 to 13 600 X g) make corrections for trapped plasma insignificant. Problems with matrix matching and viscosity are overcome by using a plasma pool standard for calculations. Values for erythrocyte lithium concentrations were unchanged in samples stored at room temperature up to 24 h. Hemolysis appears to be of possible clinical significance. This method is useful as a routine clinical laboratory procedure for monitoring patients with affective disorders, who are undergoing therapy with lithium.

背景与目标： ：我们描述了一种通过原子吸收分光光度法测定血浆和红细胞锂浓度的方法。使用锂空心阴极灯在670.8 nm处对血浆和溶血的全血进行稀释和分析。从血细胞比容间接计算出红细胞锂的浓度。在11个月内每天运行的全血0.43 mmol / L池的标准偏差为/ -20μmol/ L（CV = 5.1）。在同一时间段（n = 127）定期测定的冻干池的锂浓度为1.84 /-0.05 mmol / L（CV = 2.7％）。相对较低的红细胞/血浆锂比率和微量血细胞比容离心力（9600至13600 X g）使校正的血浆微不足道。通过使用等离子池标准进行计算，可以解决基体匹配和粘度方面的问题。在室温下保存长达24小时的样品中，红细胞锂浓度的值没有变化。溶血似乎具有潜在的临床意义。该方法可作为常规的临床实验室程序，用于监测正在接受锂疗法治疗的情感障碍患者。

BACKGROUND & AIMS: :Cell viability and cell proliferation are endpoints that can be used to identify cytotoxic effects. In a study of the cytotoxicity of four biomaterials and drugs, these two criteria were determined by different techniques. There were notable similarities and differences among the different methods used. Cell viability, which was determined by the trypan blue exclusion test, spectrophotometric microtitration (neutral red) and flow cytometry (fluorescein diacetate) gave similar results. However, the neutral red assay was found to be the most sensitive method for determining the cytotoxicity of these biomaterials and drugs. Cell proliferation measurement, by cell counts and quantitative protein estimation (coomassie blue), revealed important variations between the two methods and indicated poor sensitivity for the protein assay. A slight variability in the determination of the inhibitory concentration 50 (IC(50)) for the two drugs was observed for all the techniques.

背景与目标： ：细胞活力和细胞增殖是可用于鉴定细胞毒性作用的终点。在对四种生物材料和药物的细胞毒性的研究中，这两种标准是通过不同的技术确定的。使用的不同方法之间存在显着的异同。通过台盼蓝排除试验，分光光度微量滴定（中性红）和流式细胞术（双乙酸荧光素）测定的细胞活力得到了相似的结果。但是，发现中性红分析是确定这些生物材料和药物的细胞毒性的最灵敏方法。通过细胞计数和定量蛋白质估计（考马斯蓝）进行细胞增殖测量，揭示了这两种方法之间的重要差异，并表明蛋白质测定的灵敏度较差。在所有技术中，两种药物的抑制浓度50（IC（50））的测定均存在轻微差异。

BACKGROUND & AIMS: :Cloud point extraction with cold column trapping (CPE-CCT) was used for the rapid preconcentration and UV-Vis spectroscopy of beta-carotene in fruit juice samples. A central composite design was employed to optimize parameters such as pH, incubation time, cloud point temperature and surfactant concentration. A detection limit of 0.01 mg/L of beta-carotene (3SB/m), a coefficient of determination of 0.998 and a linear range of 0.04-10 mg/L were obtained. The CPE-CCT method was confirmed in comparison with the corresponding direct HPLC standard method. A simple, portable and cost-effective device was also utilized. Owing to eliminating centrifugation, the conditions of CPE-CCT were more moderate and its sample handling easier compared to conventional CPE.

背景与目标： ：使用冷柱捕集（CPE-CCT）进行浊点萃取可用于果汁样品中β-胡萝卜素的快速预富集和UV-Vis光谱分析。采用中央复合设计来优化参数，例如pH，孵育时间，浊点温度和表面活性剂浓度。 β-胡萝卜素（3SB / m）的检出限为0.01 mg / L，测定系数为0.998，线性范围为0.04-10 mg / L。与相应的直接HPLC标准方法相比，确定了CPE-CCT方法。还使用了一种简单，便携式且具有成本效益的设备。由于消除了离心作用，与传统的CPE相比，CPE-CCT的条件更为温和且样品处理更为轻松。

BACKGROUND & AIMS: One of the ulcerogenic mechanisms by which ethanol induces mucosal lesions in the stomach is the depression of gastric mucosal blood flow (GMBF). The goal of this study was to determine whether lesion formation is the result of vascular ischemia alone or ischemia combined with congestion. The aims of this study were to answer this question by evaluating the relationship between GMBF, oxygen saturation (ISO2) and hemoglobin volume (IHb) in the gastric mucosa under the influences of ethanol and prostaglandin E2 (PGE2) in the ischemic and congestive states, using a laser Doppler flowmeter and tissue spectrum analyzer. Ligation of the gastric celiac artery or vein markedly decreased the GMBF and the ISO2 level. The former procedure also reduced but the latter increased the IHb level. Ethanol administration produced effects similar to venous ligation, i.e. vascular stasis with ischemia. There was a negative correlation between GMBF and severity of lesion formation after ethanol administration. However, at the lesion site all the hemodynamic parameters were significantly reduced, indicating that a necrotic condition had occurred. PGE2 preincubation (25 micrograms) elevated GMBF, ISO2 and IHb levels. It also alleviated the reduction of blood flow induced by ethanol and increased the recovery rate of GMBF and ISO2 after the release of arterial or venous ligation. It is concluded that the decrease in blood flow due to ethanol is probably caused by constriction of venules rather than arterioles inside the mucosa, and this effect could lead to vascular congestion. PGE2 probably dilates both arterioles and venules in the gastric mucosa and thereby increases the blood flow in the gastric mucosa.(ABSTRACT TRUNCATED AT 250 WORDS)

背景与目标： 乙醇诱导胃粘膜损伤的致溃疡机制之一是胃粘膜血流（GMBF）降低。这项研究的目的是确定病变的形成是单独的血管缺血还是缺血与充血相结合的结果。这项研究的目的是通过评估在缺血和充血状态下乙醇和前列腺素E2（PGE2）的影响下胃粘膜中GMBF，血氧饱和度（ISO2）和血红蛋白量（IHb）之间的关系，以回答这一问题，使用激光多普勒流量计和组织频谱分析仪。胃腹腔动脉或静脉的结扎明显降低了GMBF和ISO2水平。前一种方法也减少了，但后者增加了IHb水平。乙醇给药产生的效果类似于静脉结扎，即具有缺血性的血管淤滞。乙醇施用后，GMBF与病变形成的严重程度之间呈负相关。但是，在病变部位，所有血流动力学参数均显着降低，表明已发生坏死病状。 PGE2预孵育（25微克）可提高GMBF，ISO2和IHb水平。在释放动脉或静脉结扎后，它还减轻了乙醇诱导的血流减少，并提高了GMBF和ISO2的回收率。结论是乙醇引起的血流减少可能是由于粘膜内的小静脉收缩而不是小动脉收缩引起的，这种作用可能导致血管充血。 PGE2可能会扩张胃粘膜中的小动脉和小静脉，从而增加胃粘膜中的血流量。（摘要截断为250个字）

BACKGROUND & AIMS: PURPOSE:To assess transepithelial stromal riboflavin absorption with an enhanced riboflavin solution (riboflavin 0.1%, 15% dextran T500 with trometamol (Tris-[hydroxymethyl]aminomethane) and sodium ethylenediaminetetraacetic acid by analyzing light-transmission properties of ex vivo rabbit corneas. SETTING:School of Optometry and Vision Sciences, Cardiff, Wales. DESIGN:Experimental study. METHODS:The enhanced riboflavin drops (Ricrolin TE) were applied every 3 minutes for 1 hour to 12 corneas (4 with intact epithelium, 4 with superficial scratches, 4 with 8.0 mm epithelial debridement). As a comparison, riboflavin drops without the enhancers (riboflavin 0.1%, 20% dextran T500) (normal riboflavin group) were applied to 12 corneas (4 with intact epithelium, 4 with superficial scratches, 4 with central epithelial debridement). A control group of 4 corneas with intact epithelium received balanced saline 0.9%. To assess enhanced riboflavin absorption, light-transmission spectra of the corneas were analyzed with a spectrophotometer. RESULTS:The spectra in corneas with intact epithelium in both riboflavin groups and in eyes with superficial scratches treated with normal riboflavin were similar to controls. Those with enhanced riboflavin and superficial scratches showed a homogeneous yellow discoloration of the cornea with a dip in light transmission between 400 and 490 nm, similar to that of the enhanced riboflavin solution. This was also seen, albeit of a greater magnitude, with complete epithelial removal, with eyes receiving enhanced riboflavin having a greater dip in transmission than eyes receiving normal riboflavin. CONCLUSIONS:Administration of enhanced riboflavin and superficial epithelial scratches allowed sufficient riboflavin stromal absorption to homogeneously alter the transmission spectra of rabbit corneas. This did not occur to the same extent with an intact epithelium or normal riboflavin with superficial scratches. FINANCIAL DISCLOSURE:No author has a financial or proprietary interest in any material or method mentioned.

背景与目标： 目的：通过分析离体兔角膜的透光特性，评估增强的核黄素溶液（核黄素0.1％，15％右旋糖酐T500和丁苯三酚（Tris-[[羟甲基]氨基甲烷））和乙二胺四乙酸钠对上皮间质核黄素的吸收。
地点：威尔士卡迪夫验光与视觉科学学院。
设计：实验研究。
方法：每3分钟将增强的核黄素滴剂（Ricrolin TE）应用于12个角膜（4个完整的上皮，4个表面刮擦，4个8.0 mm上皮清创术）。作为比较，将不使用增强剂的核黄素滴剂（核黄素0.1％，右旋糖酐T500）（正常核黄素组）应用于12个角膜（4个完整上皮，4个表面刮擦，4个中央上皮清创）。带有完整上皮的4个角膜对照组接受0.9％的平衡盐水。为了评估核黄素吸收的增强，用分光光度计分析了角膜的透光光谱。
结果：核黄素组中角膜完整上皮的光谱和正常核黄素治疗后表面划痕的眼睛的光谱与对照组相似。具有增强的核黄素溶液和表面刮痕的那些显示出角膜的均匀黄变色，并且具有在400至490nm之间的光透射率的下降，类似于增强的核黄素溶液。还可以看到这种情况，尽管幅度更大，完全去除了上皮，与接受正常核黄素的眼睛相比，接受增强核黄素的眼睛的透射率下降更大。
结论：施用增强的核黄素和浅表上皮擦伤可使核黄素基质吸收充分，从而均匀地改变兔角膜的透射光谱。完整的上皮细胞或正常的核黄素表面有划痕时，发生这种情况的程度不同。
财务披露：任何作者都不会对所提及的任何材料或方法具有财务或专有利益。

BACKGROUND & AIMS: :A novel diffusion cell has been constructed which allows study of membrane diffusion processes without the need for sampling of the receiver compartment, that is highly sensitive and, being based around a diode array spectrophotometer also allows for continuous, real-time recording of multi-species concentration changes in the receiving compartment. The system is controlled to operate isothermally (via a Peltier control system) at temperatures between 15 and 85 degrees C. To examine the performance of this novel design, the transfer of tetracaine from a preparation in PEG 400 (20% tetracaine in PEG 400) has been studied. The results have been used to determine flux, lag time and related parameters. The performance of the novel cell is compared with results from traditional Franz cell diffusion studies.

背景与目标： ：已构建了一种新型扩散池，该池可以进行膜扩散过程的研究，而无需对接收室进行采样，该池非常灵敏，并且基于二极管阵列分光光度计，还可以连续，实时地记录多个接收室中物种浓度的变化。控制该系统使其在15到85摄氏度之间的温度下等温运行（通过Peltier控制系统）。要检查该新颖设计的性能，可从制剂中将丁卡因转移到PEG 400中（在PEG 400中为20％丁卡因）已经研究过了。结果已用于确定通量，滞后时间和相关参数。将该新型电池的性能与传统Franz细胞扩散研究的结果进行了比较。

BACKGROUND & AIMS: :The aim was to examine the effect of retreatment process on the surface roughness and nickel titanium (NiTi) composition of ProTaper Universal Retreatment (PTUR; consists of 3 files; D1, D2, D3) and WaveOne Gold (WOG) (primary) instruments. Twenty extracted mandibular molar teeth with severe curved (30-40°) mesial roots were selected and divided into two groups (n = 10) based on the instrument used for the removal of the root canal filling. Before and after using the instruments in two canals, they were subjected to atomic force microscopy (AFM) and energy dispersive X-ray spectrophotometry (EDX) analysis. The EDX analysis data and roughness average (Ra) and root mean square (RMS) values were analyzed statistically using a one-way analysis of variance and post hoc Tukey's test at the 5% significant level. There was no significant difference between the new and used D1 and D2 PTUR and WOG instruments in terms of the Ni composition (p > .05). The Ti contents of the used D2 and D3 PTUR instruments were lower those of the new instruments (p < .05). In both new and used instruments, PTUR and WOG have no difference in terms of Ra and RMS values. (p > .05). The Ra and RMS values of the PTUR and WOG systems significantly increased after removal of the root canal filling (p < .05). The use of PTUR and WOG instruments for removal of root canal filling in severely curved root canals affected the surface topography of the files. The NiTi composition of the WOG instruments was unaffected by the retreatment process.

背景与目标： ：目的是研究再处理工艺对ProTaper通用再处理（PTUR；包括3个文件； D1，D2，D3）和WaveOne Gold（WOG）（主要）仪器的表面粗糙度和镍钛（NiTi）成分的影响。根据用于去除根管充盈的器械，选择二十颗拔除的具有严重弯曲（30-40°）近中根的下颌磨牙，并将其分为两组（n = 10）。在两条运河中使用该仪器之前和之后，都要对它们进行原子力显微镜（AFM）和能量色散X射线分光光度法（EDX）分析。使用单向方差分析和事后Tukey检验在5％显着水平下对EDX分析数据和粗糙度平均值（Ra）和均方根（RMS）值进行统计分析。在新的和使用过的D1和D2 PTUR和WOG仪器之间，在镍成分方面没有显着差异（p> .05）。所用的D2和D3 PTUR仪器中的Ti含量比新仪器要低（p <.05）。在新仪器和旧仪器中，PTUR和WOG的Ra和RMS值都没有差异。 （p> .05）。去除根管充盈后，PTUR和WOG系统的Ra和RMS值显着增加（p <0.05）。使用PTUR和WOG器械去除严重弯曲的根管中的根管充填会影响锉刀的表面形貌。 WOG仪器的NiTi成分不受再处理过程的影响。

BACKGROUND & AIMS: :We have combined the information obtained from rapid-scan electronic absorption spectrophotometry and multifrequency (9-295 GHz) electron paramagnetic resonance (EPR) spectroscopy to unequivocally determine the electronic nature of the intermediates in milk lactoperoxidase as a function of pH and to monitor their reactivity with organic substrates selected by their different accessibilities to the heme site. The aim was to address the question of the putative catalytic role of the protein-based radicals. This experimental approach allowed us to discriminate between the protein-based radical intermediates and [Fe(IV)=O] species, as well as to directly detect the oxidation products by EPR. The advantageous resolution of the g anisotropy of the Tyr (*) EPR spectrum at high fields showed that the tyrosine of the [Fe(IV)=O Tyr (*)] intermediate has an electropositive and pH-dependent microenvironment [g(x) value of 2.0077(0) at pH >or= 8.0 and 2.0066(2) at 4.0

BACKGROUND & AIMS: :A method for the direct determination of methemalbumin in serum by means of difference scanning spectrophotometry is described. The advantages of this quantification technique resides in the ability to obviate unequal background characteristics such as turbidity in one treated sample portion, the avoidance of subtractive measurement on the sides of steep spectra, and a qualitative observation simultaneously derived from the single difference scan. A measure of the stability of the prepared standards is described along with a minimized use of sample and reagent volumes if the latter is desired.

背景与目标： ：描述了一种通过差示扫描分光光度法直接测定血清中的甲基白蛋白的方法。这种定量技术的优势在于能够消除不相等的背景特征，例如在一个处理过的样品部分中出现浑浊，避免在陡峭光谱两侧进行减法测量以及同时从单次差值扫描中获得定性观察。描述了所制备标准品的稳定性的度量，以及如果需要样品和试剂量最少的情况，请尽量减少使用。

BACKGROUND & AIMS: The first order rate constants for the dissociation of daunorubicin, doxorubicin, and 1-; 1,4-; 1,5-; and 1,8-; N,N-diethylaminoethylamino-substituted anthraquinones from calf thymus DNA were determined using stopped-flow spectrophotometry. Sodium dodecyl sulphate was used to disrupt the equilibrium. In all cases there was an increase in the rate constant with temperature. The dissociation rate constants at 20 degrees, 25 degrees and 37 degrees, were in the order 1-; much greater than 1,8-; greater than 1,4-; greater than daunorubicin and doxorubicin greater than 1,5-disubstituted anthraquinone. The 1,5-disubstituted anthraquinone (VII) thus shows the slowest rate of dissociation from DNA; the DNA complex dissociating more slowly than the DNA complexes of the anthracyclines, daunorubicin and doxorubicin. The result is consistent with the data from computer graphics modelling studies [39] which show that DNA-breathing (transient base pair unstacking) has to occur to allow the docking of the 1,5-disubstituted anthraquinone (VII) into the receptor site. Hence once the 1,5-disubstituted anthraquinone molecule has intercalated into DNA, DNA-breathing is required before dissociation can take place. This is not necessary with the other compounds (though the 1,4-disubstituted anthraquinone (V) can bind in this manner as well). So the very slow dissociation of the DNA/1,5-disubstituted anthraquinone complex relative to that of the DNA complexes of the other compounds examined here, supports the proposed mode of binding [39].

背景与目标： 柔红霉素，阿霉素和1-解离的一级速率常数； 1,4-; 1,5-;和1,8-;使用停止流光度法测定小牛胸腺DNA中N，N-二乙基氨基乙基氨基取代的蒽醌。用十二烷基硫酸钠破坏平衡。在所有情况下，速率常数均随温度增加。在20度，25度和37度下的解离速率常数为1-的数量级；远远大于1,8-;大于1,4-;大于柔红霉素和阿霉素大于1,5-二取代的蒽醌。因此，1,5-二取代的蒽醌（VII）显示出从DNA解离的最慢速率。与蒽环霉素，柔红霉素和阿霉素的DNA复合物相比，DNA复合物解离的速度更慢。结果与计算机图形学研究的数据一致[39]，该研究表明必须进行DNA呼吸（瞬态碱基对解叠）才能将1,5-二取代的蒽醌（VII）对接到受体位点。因此，一旦1,5-二取代的蒽醌分子插入DNA中，就需要进行DNA呼吸，然后才能发生解离。对于其他化合物，这不是必需的（尽管1,4-二取代的蒽醌（V）也可以这种方式结合）。因此，DNA / 1,5-二取代蒽醌复合物的解离速度相对于此处检测的其他化合物的DNA络合物而言非常缓慢，支持拟议的结合方式[39]。

BACKGROUND & AIMS: BACKGROUND:Plasma chitotriosidase had been proposed as a biochemical marker of macrophage accumulation in several lysosomal storage disorders. The selection of wavelength and possible interferences and errors have not yet been explored in the assay of chitotriosidase activity. We evaluated the feasibility of measurement of plasma chitotriosidase activity by fluorescence spectrophotometry and established pediatric reference values for earlier diagnosis of related diseases. METHODS:We assayed plasma chitotriosidase activity in 104 healthy Chinese children by a fluorometric approach which combines 3-dimension scan spectra, wavelength scan spectra, time scan spectra and fluorescence intensity analysis. RESULTS:The optimal excitation wavelength and emission wavelength were 358 and 448 nm, respectively. A change of enzyme activity over time was observed fluorometrically, The reference value was 13.04+/-4.94 nmol/ml/h (12.45+/-4.37 nmol/ml/h for boys and 14.04+/-3.99 nmol/ml/h for girls). CONCLUSIONS:We present an integrated application of the fluorescence spectrophotometry as an ideal tool to determine enzymatic activity with 4-methylumbelliferyl triacetylchitotrioside as labeled substrates in clinical laboratory. The function of 3D scan was proved powerful in determination of plasma chitotriosidase activity. The establishment of plasma chitotriosidase activity reference pediatric values was potentially useful for the evaluation of all related diseases.

背景与目标： 背景：血浆壳三糖苷酶已被提出作为巨噬细胞在几种溶酶体贮积病中积累的生化标志物。在壳三糖苷酶活性的测定中尚未探索波长的选择以及可能的干扰和误差。我们评估了通过荧光分光光度法测量血浆壳三糖苷酶活性的可行性，并建立了儿科参考值以早期诊断相关疾病。
方法：我们采用荧光分析法，结合了三维扫描光谱，波长扫描光谱，时间扫描光谱和荧光强度分析方法，对104名健康中国儿童的血浆壳三糖苷酶活性进行了测定。
结果：最佳激发波长为358 nm，发射波长为448 nm。用荧光法观察到酶活性随时间的变化。参考值为13.04 /-4.94 nmol / ml / h（男孩为12.45 /-4.37 nmol / ml / h，女孩为14.04 /-3.99 nmol / ml / h）。
结论：我们提出了荧光分光光度法的综合应用，作为在临床实验室中以4-甲基伞形酮基三乙酰基壳三糖苷为标记底物确定酶活性的理想工具。实践证明，3D扫描功能在确定血浆壳三糖苷酶活性方面具有强大的作用。血浆壳三糖苷酶活性参考儿科值的建立可能对所有相关疾病的评估有用。