On the influence of reaction conditions in activity determination of alkaline phosphatase on the molar absorptivity of 4-nitrophenol

In activity determination of alkaline phosphatase (AP), measuring temperature, type and concentration of buffer, and protein concentration in the test influence the molar absorptivity of 4-nitrophenol. Thus systematic errors of up to 3% may occur in activity determinations of AP if these influences are not taken into account.     

Evaluation of absorption and first- and second-derivative spectra for simultaneous quantification of bilirubin and hemoglobin

We discuss the relative merits of absorption and first- and second-derivative spectra for the simultaneous quantification of bilirubin and hemoglobin, and evaluate single-, two-, and multiwavelength methods. Although both species can be quantified from single- or two-wavelength absorption data, lipids or other absorbing or light-scattering components introduce systematic errors that can be substantially decreased by using first- or second-derivative spectra. Multi-wavelength data-processing methods with derivative spectra permit quantification of components with overlapping spectra and decrease the random error usually associated with derivative methods. A typical least-squares equation for quantifying bilirubin in the presence of hemoglobin and bovine serum albumin from multi-wavelength second-derivative data is y(computed) = 0.999x(prepared) + 0.00 mg/L.     

胆红素测定校准物二牛磺酸胆红素的研究

对合成的二牛磺酸胆红素的部分理化性质、吸收光谱及与重氮试剂反应的特点做了探讨。结果表明，二牛磺酸胆红素作为总胆红素测定时的校准物，效果与用非结合胆红素（Ｂｕ）作校准物一致；而作为直接胆红素（ＤＢＩＬ）测定时的校准物则优于Ｂｕ；当前在没有葡萄糖醛酸胆红素商品的情况下，二牛磺酸胆红素是胆红素测定时，尤其是ＤＢＩＬ测定的理想校准物。     

Delta bilirubin in serum of pediatric patients: correlations with age and disease

At least four bilirubin fractions can be separated and identified by liquid chromatography, the least understood being the "delta" fraction (B delta), which apparently is covalently bound to albumin. To learn more about the incidence and significance of B delta, we assayed serum from 539 infants and children, both by the chromatographic method and the routine colorimetric Jendrassik-Grof method. The proportion of B delta appeared to correlate with both age and disease course. For infants younger than 28 days B delta generally was less than 2% of total bilirubin; for hyperbilirubinemic older infants and children the median B delta value was 35%. High B delta (greater than 50% of total bilirubin) in newborns was associated with intra- and extra-hepatic cholestasis, biliary cirrhosis, biliary atresia, and hepatitis. Among older infants and children, a proportion of low B delta (less than 10%) was found in hemolytic anemias, sepsis, shock, and other non-hepatic jaundice. In several cases, when low B delta was accompanied by increased conjugated bilirubin, the prognosis was very poor. Delayed clearance of B delta from the circulation together with its reactivity in direct diazo methods may interfere with interpretation of values for conjugated bilirubin as measured by classical methods.     

A single nonaqueous diazo reagent for the rapid determination of bilirubin in serum without lipemic interference

A nonaqueous reagent for directly determining serum bilirubin with 3,3'-dimethoxydiphenyl-4,4'-tetrazonium chloride in acidified dimethylsulfoxide is described. Conjugated or unconjugated bilirubin may be determined after extraction in acidified chloroform-ethyl acetate. The procedure is accurate (r² 0.97; recovery 100% for total, 98% for extracted bilirubin) and precise (C.V. 3.0% at 65 mg bilirubin per 1. The reagent develops endpoint color at 590 nm in less than 2 min, and the developed absorbance is stable for several hours. The method is intended for special applications where gross lipemia is encountered. Standardization with pure bilirubin in dimethylsulfoxide or chloroform is identical to standardization with aqueous bilirubin in protein standards.     

Determination of serum bilirubin concentration during phototherapy of newborns and in vitro: results compared by the direct spectrometric method and the diazo method

During direct illumination of a serum bilirubin solution the bilirubin concentration decreased markedly, both as determined by the direct spectrometric method and (even more so) by the diazo method. In contrast, I found the same values for serum bilirubin concentrations as determined by these two methods for serum from untreated, "single light", and "double light" treated full-term infants with neonatal hyperbilirubinemia without blood type immunization. The same was true for untreated and "single light" treated premature infants with this disease. Furthermore, no difference was found in the above-mentioned relationship between "single light" treated infants with the same disease, and untreated infants with neonatal hyperbilirubinemia without immunization, all born at term. This is important, because the direct spectrometric method is simpler and requires less serum than does the diazo method.     

Delta and conjugated bilirubin as complementary markers of early rejection in liver-transplant recipients

For 51 liver allograft recipients, we evaluated whether serum profiles of delta (Bd) and conjugated bilirubins (Bc) could be used to diagnose rejection during the first 30-50 postoperative days, in comparison with histology as the "gold standard." Daily measurements of aspartate aminotransferase, alkaline phosphatase, total bilirubin, Bd, and Bc were made, the last two by liquid chromatography. In 34 patients without any biochemical or histological evidence of rejection, within seven to 10 postoperative days Bd increased to greater than 40-50% of total bilirubin, while Bc decreased to less than 10%. In patients with severe rejections resulting in death, Bc increased rapidly to greater than 50%, while Bd remained less than 30%. In 24 histologically proven episodes of rejection in 17 patients there was either a rapid decrease in Bd or its persistence at 30%, plus either a steep increase in Bc, or its remaining at greater than 50% total bilirubin. Treatment of rejection resulted in a prompt reversal of these trends. Individually promising as prognostic adjuncts to existing liver-function markers, Bd and Bc also complemented each other, rendering the diagnosis of liver rejection much more incisive.     

Spectrophotometric study of bilirubin interference in the huang reaction for cholesterol

The difficult problem of ascribing the measure of bilirubin interference in a direct Liebermann-Burchard reaction (LB) for serum cholesterol has been investigated. Various parameters in this reaction have been described. The effect on the reaction temperatures of the addition of an aqueous sample and non-aqueous standard to the reagent solution indicates that this factor may be uncontrolled. The results obtained on studying the different initial starting temperatures has been shown to influence the final absorbance values variably at the two reported wavelengths of measurement. Spectra showing the effect of varying time and temperatures on the reactions of cholesterol, bilirubin and cholesterol—bilirubin mixtures with the Huang modification of the L—B reagent are detailed, along with the consideration of the choice of wavelength of measurement on cholesterol to bilirubin absorbance ratios. The validity or non-validity of suggested blanks is shown spectrophotometrically. The conclusion arrived at is that a correction for bilirubin interference in this direct reaction is quite difficult. For comparison purposes the reactions of p-toluene sulfonic acid and ferric chloride reagents with bilirubin are shown.     

Interaction of beta-lactam antibiotics on bilirubin-albumin complex: comparison by three methods, total bilirubin, unbound bilirubin and erythrocyte-bound bilirubin

The effects of 'third-generation' cephalosporins and penicillin analogues on the concentrations of total unconjugated bilirubin, unbound bilirubin and erythrocyte-bound bilirubin were determined in blood samples. This study was performed, in vitro, at two bilirubin/albumin molar ratios and at various concentrations of antibiotics. The most effective displacers, considering the three methods, were antibiotics tightly bound to albumin: ceftriaxone and cefotetan. Cefoperazone, which is bound to albumin as tightly as these two antibiotics, caused no significant increase in unbound bilirubin but should be considered as a displacer drug on the basis of the variations of erythrocyte-bound bilirubin and total bilirubin. We suggest that drug interaction on bilirubin-albumin binding be investigated by several methods.     

Novel edaravone-based azo dyes: efficient synthesis,characterization, antibacterial activity,DFT calculations and comprehensive investigation of the solvent effect on the absorption spectra

The present study deals with designing and synthesizing novel dyes using the drug combination of edaravone and azo compounds which can be used as an indicator for anions and cations. The desired product synthesis was accomplished via a two-step process involving diazotizing the aromatic amines followed by the resultant salts coupling with edaravone. The resulting dyes were obtained with high yields under mild conditions. The structures of the dyes were identified with UV-vis, FT-IR, ¹H NMR and ¹³C NMR spectra and CHN analysis. To investigate the solvatochromism effect, the interaction of different solvents with the selected dyes was evaluated using several parameters including the dielectric constant, refractive index, hydrogen bond donating ability, hydrogen bond accepting ability and dipolarity/polarizability scale. To achieve deep understanding about the stability and geometrical characteristics of the azo–hydrazo tautomers of the synthesized dyes and their UV-visible spectra prediction, some DFT calculations were also carried out on the synthesized dyes. The antibacterial activities of some synthesized compounds were also evaluated using the disk diffusion method. The results revealed different activity of the selected synthesized dyes for antibacterial tests against selected Gram positive and Gram negative bacteria.

The present study deals with designing and synthesizing novel dyes using the drug combination of edaravone and azo compounds which can be used as an indicator for anions and cations.     

Interdisciplinary and distance education in the Delta: the Delta Health Education Partnership

The purpose of this article is to describe the activities and outcomes of the Delta Health Education Partnership (DHEP), an interdisciplinary and distance education program developed to promote 'anytime, anywhere' education. The goal of the project is to recruit, educate, and retain interdisciplinary groups of primary care health practitioners to increase access to health care in medically underserved and health professional shortage areas of the lower Mississippi Delta. The targeted health providers are certified nurse midwives, physician assistants, and family nurse practitioners. The DHEP program spans six universities across four primarily rural states. Primary health care students in the lower Mississippi Delta region are taught using asynchronous technology strategies including Internet-based coursework. Opportunities to expand educational options for distance learners and geographically bound students are explained. In addition, methods of building community partnerships in an effort to recruit and retain primary care providers are also explained. The advantages and limitations of the asynchronous Internet-based courses are explored as part of the program evaluation.     

Interdisciplinary and distance education in the Delta: the Delta Health Education Partnership

The purpose of this article is to describe the activities and outcomes of the Delta Health Education Partnership (DHEP), an interdisciplinary and distance education program developed to promote 'anytime, anywhere' education. The goal of the project is to recruit, educate, and retain interdisciplinary groups of primary care health practitioners to increase access to health care in medically underserved and health professional shortage areas of the lower Mississippi Delta. The targeted health providers are certified nurse midwives, physician assistants, and family nurse practitioners. The DHEP program spans six universities across four primarily rural states. Primary health care students in the lower Mississippi Delta region are taught using asynchronous technology strategies including Internet-based coursework. Opportunities to expand educational options for distance learners and geographically bound students are explained. In addition, methods of building community partnerships in an effort to recruit and retain primary care providers are also explained. The advantages and limitations of the asynchronous Internet-based courses are explored as part of the program evaluation.     

Disulfide–yne reaction: controlling the reactivity of a surface by light

In this paper we provide new insight into the disulfide–yne photo reaction, which is similar but different from the well-known thiol–yne photoclick reaction. We show that, unlike the stable product generated from thiol–yne chemistry, the vinyl dithioether structure obtained from disulfide–yne reaction exhibits unique reactivity with thiols and disulfides, which can be used for surface photochemistry to fabricate reactive and dynamic surfaces. The possible mechanism for the unique reactivity of vinyl dithioether structure was discussed. We demonstrated that disulfide–yne reactions are highly compatible with thiol–yne chemistry, but offer the flexibility and dynamic nature that is lacking in thiol–yne chemistry, thus could be a good replenishment for the existing thiol–yne toolbox.

The interesting disulfide–alkyne chemistry provides the kinetics of the widely used thiol–alkyne chemical reaction.