碳酸酐酶法测定乳汁锌

目的建立灵敏、准确、特异且试剂稳定的碳酸酐酶法测定乳汁锌。方法乳汁灰化后溶于0．1mol／L HCl．测定前先用0．01mol／L NaOH稀释并中和酸．测定时待分析液巾锌离子复活脱辅基的碳酸酐酶，以醋酸对硝基酚作为酶促反应底物进行测定。结果线性范围达61．2μmol／L。回收率95．6％～103．8％，批内和批间变异系数分别小于3．5％与4．9％，本法（X）与原子吸收分光光度法（Y）比较具有良好的相关性，Y=0．986X＋0．033,r=0．988。Cu^2＋、Fe^3＋、Mn^2＋各200μmol／L对锌测定均无影响；Co^2＋10μmol，L以下对本法测定乳汁锌结果也无干扰。结论该法具有特异、准确、灵敏且试剂稳定等优点．适合于生化分析仪检测乳汁锌。     

血清锌的自动分析法

目前 ,临床上测定血清锌的方法主要为原子吸收分光光度法和 2 (5 溴 2 吡啶偶氮 ) 5 二乙氨基酚 (5 Ｂｒ ＰＡＤＡＰ)分光光度法 ,其中原子吸收分光光度法需要专用仪器 ,操作繁琐 ;5 Ｂｒ ＰＡＤＡＰ分光光度法需去蛋白或消化 ,且需血量大。本研究通过加速血清锌解离和     

BUN在半自动生化分析仪RA-50上的速率法测定

传统上BUN是以两点法进行测定的,但随着产品原料的质量提高,试剂配方的日臻完善,BUN测定的反应曲线已具有相当好的线性,因此,现在主要是采用速率法来对BUN进行测定。在RA-50仪器上,可以使用两点法来进行BUN、CRE等项目的测定。因其速率法没有带标准测定的功能,欲用速率法对BUN进行测定需先解决定标问题。首     

血清总胆红素两点终点法测定

血清总胆红素（TBIL）测定一般多用单试剂法，因未做样本空白，样本的干扰因素如色泽、脂血等会影响测定结果的准确性，笔者用2，4-二氯苯胺（2，4-Dichloranilin，缩写DLAN），采用两点终点法在自动分析仪上测定TBIL，取得较好的效果。     

血清锌自动化分析法的临床应用

1　材料和方法1.1　仪器　日立 7170 A全自动生化分析仪 (日本产 )。1.2　试剂　 1锌标准液 :30 .6μmol/ L ;2试剂 :购买中美合资宁波亚太生物技术公司生产的试剂盒。1.3　方法　日立 7170 A测定参数 :标准液浓度 30 .6 ,标本量5 .0μL ,试剂量 10 0μl测定方法 1点法 ,副 /主波长 70 0 nm /5 70 nm,测定点 (10 ) (5 )。2　结果2 .1　波长选择　锌与络合剂 5 - Br PAPS反应产生紫红色络合物的最大吸收波长为 5 6 0 nm,本仪器无此波长 ,故选用 5 70 nm为主波长。2 .2　标准曲线　按本方法测定 ,锌含量在 2～ 6 0μmol/ L范围内观察仪器…     

自动生化分析仪ALT测定校验程序的建立与应用

目的建立全自动生化分析仪校验程序。方法应用对硝基酚(PNP)在不同pH环境中吸收峰特性,对奥林巴斯AU-400自动生化分析仪340nm/410nm进行精密度检测。结果连续记录30个工作日批内变异系数均未超过1.00%;日间变异系数为0.64%。结论使用校验程序每日进行自动生化分析仪精密度检测,经济、简便、实用,能实时、有效地反映仪器的加样系统和比色系统的工作性能。     

重氮法测定γ-GT基质重组和影响因素分析

血清γ-GT测定以γ-谷氨酰对硝基苯胺为底物时，释出的对硝基苯胺含量低、色浅、吸光度低，对结果影响较大。国内目前仍常用重氮显色法，为缩短该法的反应时间，较好的控制实验条件，本文将其基质重组和对影响因素作了初步分析。现报道如下。     

尿液碘两点速率法的建立及评价

目的 用尿液碘快速测定商品试剂,建立全自动生化分析仪检测尿液碘的两点速率法,并评估其检测性能.方法 根据碘催化过氧乙酸氧化3,3',5,5'-四甲基联苯胺(TMB)的化学反应原理及全自动生化分析仪的工作特点,改变尿液碘快速测定商品试剂,建立尿液碘两点速率法,分析其线性范围、回收率、最低检测限和精密度,并与原试剂盒手工定...     

鸟氨酸氨基甲酰转移酶速率法测定的初步探讨

目的 建立鸟氨酸氨基甲酰转移酶(OCT)自动化分析的方法.方法 在磷酸盐缓冲液(pH值7.2)条件下,以瓜氨酸为底物,经一系列酶偶联反应,尼克酰胺腺嘌呤二核苷酸(NADH+H+)被氧化为氧化型辅酶Ⅰ(NAD+),340 nm处测定吸光度(A)变化值,A值下降的速率与待测样本中的OCT含量成正比关系,间接求出OCT的活性.结果 本法最适pH值为7.2,最适底物浓度为2.0 mmol/L.批内、批间平均变异系数(CV)分别为3.80%、4.08%.米氏常数(Km)值为0.16 mmol/L.回收率达91.56%.在320 U/L内线性良好.参考范围为0～18 U/L.结论本方法能够快速、简便、准确的测定OCT活性,适用于各类全自动生化分析仪.     

Regulation of hemoglobin affinity for oxygen by carbonic anhydrase

We studied the effect on hemoglobin (Hb)-oxygen affinity induced by changes in carbonic anhydrase (CA) activity. Oxygen partial pressure at the 50% saturation of Hb (P(50)) in human blood was measured as CA activity was inhibited to varying degrees with acetazolamide (AZ; 100 and 200 microg/mL). Transient but significant change in P(50) was observed when AZ was administered and the CO(2) concentration was changed from 10% to 5%. Finally, the differences induced with AZ were attenuated when the blood sample was subjected to 4 hours of tonometry. The findings in this study could be accounted for by reduced velocity of pH changes caused by the inhibition of CA by AZ. We conclude that CA can change Hb's affinity for oxygen by controlling the movement of CO(2) gas between air and liquid compartments.     

Respiratory function and carbonic anhydrase inhibition

Acetazolamide (Diamox) induced carbonic anhydrase inhibition is an efficient means of eliminating surplus water and bicarbonate in the overhydrated and alkalotic patient. Previous studies have demonstrated an unexpected and unexplained increase in arterial and venous oxygenation during acute carbonic anhydrase inhibition. In the present investigation we assessed the effect of acetazolamide 15 mg kg^-1 on pulmonary gas exchange in 10 critically ill, mechanically ventilated patients. Median arterial oxygen tension increased by 0.9 kPa and central venous oxygen tension and content by 16–18% and 6–8% respectively. The improved oxygenation could, however, not be attributed to an improved pulmonary oxygen exchange as both pulmonary venous admixture (Q_sQ_t ^–1) and physiological dead space ventilation (V_DV_T ^-1) increased. The increase in arterial oxygen tension can be explained by a rightward shift of the oxyhemoglobin dissociation curve due to the increased acidity of the blood during carbonic anhydrase inhibition (Bohr effect). Acetazolamide does not depress oxygen consumption, so the increase in central venous oxygen content probably reflects an improved cardiac performance. This could conceivably be mediated via sympathetic activation in response to acetazolamide induced carbon dioxide retention.     

Therapeutic applications of glycosidic carbonic anhydrase inhibitors

The zinc enzymes carbonic anhydrases (CAs, EC 4.2.1.1) are very efficient catalysts for the reversible hydration of carbon dioxide to bicarbonate and hence play an important physiological role. In humans, 16 different isozymes have been described, some of them being involved in various pathological disorders. Several of these isozymes are considered as drug targets, and the design of selective inhibitors is a long‐standing goal that has captured the attention of researchers for 40 years and has lead to clinical applications against different pathologies such as glaucoma, epilepsy, and cancer. Among the different strategies developed for designing selective CA inhibitors (CAIs), the “sugar approach” has recently emerged as a new attractive and versatile tool. Incorporation of glycosyl moieties in different aromatic/heterocyclic sulfonamide/sulfamides/sulfamates scaffolds has led to the development of numerous and very effective inhibitors of potential clinical value. The clinical use of a highly active carbohydrate‐based CA inhibitor, i.e., topiramate, constitutes an interesting demonstration of the validity of this approach. Other carbohydrate‐based compounds also demonstrate promising potential for the treatment of ophthalmologic diseases. This review will focus on the development of this emerging sugar‐based approach for the development of CAIs. © 2008 Wiley Periodicals, Inc. Med Res Rev, 29, No. 3, 419‐435, 2009     

An evaluation of cytosolic erythrocyte carbonic anhydrase and catalase in carcinoma patients: an elevation of carbonic anhydrase activity

OBJECTIVES: The antioxidant enzyme catalase and the CO2/HCO3- exchange enzyme carbonic anhydrase are both present in significant amounts in the cytosol of erythrocytes. The aim of the present study was to investigate whether these erythrocyte enzyme activities are altered in patients who have carcinoma. DESIGN AND METHODS: Cytosolic erythrocyte enzyme activities were measured in 108 cancer patients presenting with carcinoma at one of variable sites, prior to clinical treatment. These were compared with an age- and sex-matched control group of 31 healthy volunteers. RESULTS: Mean (+/-SD) catalase activities did not differ significantly, i.e. 0.0035 (+/-0.0015) EU/ml in carcinoma patients vs. 0.0031 (+/-0.00075) EU/ml in controls. However, mean carbonic anhydrase activities of 204 (+/-91) EU/ml in the carcinoma patients were significantly higher than the 158 (+/-35) EU/ml in controls (P value of 0.0065). CONCLUSION: Cytosolic erythrocyte carbonic anhydrase levels may warrant further investigation as a potential peripheral marker in cancer.