Metabolism of methylated arsenic compounds by arsenic-resistant bacteria (Klebsiella oxytoca and Xanthomonas sp.)

Two bacteria exhibiting resistance to toxic arsenic were isolated. These had been contaminated with arsenic in a Chlorella sp. culture medium containing arsenic. The two bacteria were identified as Klebsiella oxytoca and Xanthomonas sp., and grew well in a peptone medium at neutral pH at 30°C, reaching the stationary phase in ca 100h and 70h, respectively. The growth of the bacteria was not affected by arsenic(V) concentrations in the medium as high as 1000mg dm^?3. The bacteria bioaccumulated arsenic, a part of the arsenic being methylated. The bioaccumulation exhibited its peak around the turing point from the log phase to the stationary phase. The relative content of methylated arsenic in the excrement was greater than that in the bacterial cells. Adaptation treatment of inorganic arsenic caused an increase in the bioaccumulation of inorganic arsenic by K. oxytoca. Such a situation was not observed in the case of Xanthomonas sp. The bacteria also bioaccumulated methylated arsenic compounds, and demethylation of these species was observed. When the bacteria were killed by ethanol, arsenic was not taken up by the cells.     

饲料及体重对大黄鱼排氨率影响的初步研究

以大黄鱼为研究对象，进行了饲料和体重对其氨氮排泄率影响的实验．研究结果表明，大黄鱼的排氨率受饲料影响显著，投喂配合饲料的排氨率约为投喂杂鱼饲料的2倍，两者存在显著差异（P〈0．05）．投喂配合饲料的平均排氨率分别达到5．82±0．94mg·（h·kg）^-1（116．7g）、4．80±0．48mg·（h·kg）^-1（204．9g）、3．43±0．53mg·（h·kg）^-1（313．5g），而投喂杂鱼饲料的平均排氨率分别只有3．16±0．20mg·（h·kg）^-1（116．7g）、2．41±0．18mg·（h·kg）^-1（204．9g）、1．93±0．11mg·（h·kg）^-1（313．5g）；大黄鱼排氨率同样受体重影响，并且随着体重的增加排氨率减少，二者的关系式分别为线性方程：U=-0．006 1W＋3．798（R^2=0．8963）（杂鱼饲料）和U=-0．012 1W＋7．251（R^2=0．7527）（配合饲料）．     

A further investigation on a MALDI‐based method for evaluation of markers of renal damage

The validity of the urinary protein profile to characterize the pathological states of diabetic, nephropathic and diabetic–nephropathic patients was considered on the basis of previously obtained results by MALDI/MS, showing a different abundance ratio of the collagen α1 and α5 chain precursor fragments at m/z 1219 and 2049 and of the uromodulin precursor fragment at m/z 1912 observed in healthy subjects and patients; a larger number of subjects was examined and the obtained results were statistically evaluated. The p values related to the observed differences indicate that they are statistically significant when comparing all patients versus healthy controls, diabetic with normo or microalbuminuria versus nephropathic with advanced renal disease patients and diabetic with normo or microalbuminuria versus diabetic with advanced nephropathy patients. The scatter plot matrix gives evidence of the strict inverse relationship between the abundances of ions at m/z 1912 and 1219, the correlation coefficient being particularly high (r = 0.921, p < 0.001). The relationship between the true positive rate (sensitivity) and false positive rate (1—specificity) for every possible cutoff value in abundance of the considered ionic species was investigated through the receiver‐operating characteristic (ROC) curve. The obtained data indicate that a good differentiation of nephropathic patients with advanced renal disease and diabetic patients with advanced nephropathy versus healthy subjects can be easily obtained by this approach. Copyright © 2009 John Wiley & Sons, Ltd.     

Growth habits of hippuric acid in gel

Hippuric acid [C₆H₅CONHCH₂COOH], also called as N‐benzoylglycine, an organic chemical constituent of urinary stone was crystallized in silica gel in our laboratory earlier. Presently, two different habits of hippuric acid are noted during crystallization in gel. The two habits of gel grown hippuric acid crystals were characterized using single crystal X‐ray diffraction and density values. Scanning electron microscopic (SEM) studies were also made. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

UHPLC‐MS method for determination of gambogic acid and application to bioavailability,pharmacokinetics, excretion and tissue distribution in rats

A sensitive ultrahigh performance liquid chromatography tandem mass spectrometry (UHPLC‐MS) method was developed for determination of gambogic acid (GA) in rat plasma, urine, bile and main tissues. GA was separated on an Agilent Zorbax XDB–C₁₈ column (50 × 2.1 mm, 1.8 µm) with gradient mobile phase at the flow rate of 0.2 mL/min. The detection was performed by negative electrospray ionization with multiple reaction monitoring mode. The calibration curves of GA were linear between 1.0 and 1000 ng/mL in rat plasma and bile and between 1.0 and 500 ng/mL in urine and tissues. The lowest limit of quantification for all matrices was 1.0 ng/mL. Both accuracy and precision of the assay were satisfactory. This validated method was firstly applied to bioavailability (BA), pharmacokinetics, excretion and tissue distribution in rats. The BAs of GA (40 and 80 mg/kg) in rats were 0.25 and 0.32%, respectively. GA was distributed extensively in rats after oral administration and exhibited the highest level in liver. GA reached the cumulative excretion amount of 25.3 ± 1.7 µg in bile and 0.275 ± 0.08 µg in urine after i.g. 80 mg/kg to rats at 24 h. The present results would be helpful for further clinical use of GA as a potential anticancer drug. Copyright © 2015 John Wiley & Sons, Ltd.     

A novel LC‐MS/MS method for determination of tissue distribution and excretion of timosaponin B‐II in rat biological matrices

Timosaponin B‐II (TB‐II) is a natural bioactive steroid glycoside extracted from the Chinese medicinal herb Anemarrhena asphodeloides Bge. (Fam. Liliaceae). It has been demonstrated to have a good anti‐inflammatory effect and a low bioavailability (1.1%). Clinical research has focused on developing it into a completely new medicine. In this study, a rapid and sensitive analytical method based on LC‐MS/MS has been developed for the determination of TB‐II in rat biological matrices (tissues, bile, urine and feces samples). The analytes and internal standard were isolated from 100 μL samples by solid‐phase extraction and then separated using a DIKMA Inertsil ODS‐3 column (5 µm, 2.1 × 150 mm) with an isocratic mobile phase consisting of acetonitrile–0.05% formic acid (35:65) at a flow rate of 0.25 mL/min. Calibration curves (1/χ²‐weighted) offered satisfactory linearity (r² ≥ 0.990) within the test range. The accuracy, precision, recoveries and matrix effects were satisfactory in all the biological matrices examined. The assay was successfully applied to a tissue distribution and excretion study in rats. The preclinical data are useful for the design of clinical trials of TB‐II. Copyright © 2013 John Wiley & Sons, Ltd.     

The Use of Radioactive Isotopes for the Study of the Metabolism of Certain Biomedically Essential Elements: I. Metabolism of Iron

The use of radioactive isotopes in the clarifaction of the metabolism of some elements play an important role in the life cycle. A systematic study is presented on the extraction of ionic iron from urine. As radioactive isotopes, ⁵⁹Fe was used to follow the extraction of the ionic forms in various extraction systems. For this study we used tributyl phosphate (TBP) as solvent. Such studies are useful to develop procedures for the separation and analysis of these elements such as for example in the study of the treatment of anaemia by the administration of their compounds in the human body.     

Experience with the [13C2]Oxalate Absorption Test

Abstract

Hyperoxaluria is the most important risk factor for a formation of calcium oxalate-urinary stones. Usually, the bulk of oxalate will be formed in the human body, but in many patients the oxalate from food plays the decisive role. Conventionally, in urine the endogenous oxalate can not be distinguished from food derived oxalate. We have developed a standardized oxalate-absorption test, applying a physiological dose (50 mg disodium salt of [¹³C₂]oxalic acid) of labelled oxalate. The assay has been published. Now we report on the first extensive applications of this test in 86 volunteers and 135 patients from different groups with calcium oxalate stones or an increased risk of the formation of such stones. In one-third of the patients with calcium oxalate-urinary stones an oxalate hyperabsorption was diagnosed. For these patients, a dietetic stone prophylaxis and/or therapy is indicated.     

Biological Characteristics of 131I Labelled Bromsulphophthalein

Biological properties of bromsulphophthalein labelled with ¹³¹I (BSP¹³¹I) were investigated on experimental animals. Maximum activity was found in the tissue of healthy liver shortly after injection of the preparation. Forms of BSP¹³¹ I excreted through bile were analyzed chromatographically. It has been proved by the obtained radiochromatograms that the greatest part of activity is concentratd in the form of free BSP¹³¹ I while the activity found in the conjugated form ist considerably lower.     

Excretion of Hydroxy Derivatives of Polycyclic Aromatic Hydrocarbons of the Masses 178, 202, 228 and 252 in the Urine of Coke and Road Workers

Abstract

Urinary PAH-metabolite excretion by non-exposed volunteers, temporarily living on a PAH-poor and PAH-rich diet, respectively, as well as by occupationally PAH-exposed coke plant workers and road workers has been studied. Significant differences in the amount of the metabolites excreted in the urine were detected; the ratio of various metabolites was also found to be different. The mass excretion per liter of the metabolites from phenanthrene was found to be for the unexposed volunteers about 3.5μg/1, for coke plant workers about 70μg/l and for road workers about 35 μg/l. For the metabolites of chrysene the values were 0.03 μg/1 2.5 μg/l and 0.09μg/l, respectively, and for the total metabolites of benzo(a)pyrene: 0.006μg/l for unexposed persons, 0.37 μg/l for coke plant workers and 0.019 μg/l for road workers.