Evaluation of thyroid scintigraphy in small animals

Thyroid scintigraphy in rats and mice with 99mTc and 123I was attempted to examine whether this modality might be used in small animals and to describe the possibilities of its application in examining experimentally produced thyroid diseases. A human gamma camera with a pinhole collimator improved for small animals was used for imaging. Thyroid images with 99mTc were obtained 20 minutes after injection and those with 123I were 24 hours after administration. All the scintigrams, although those obtained from mice with 99mTc displayed overlapped salivary gland images, demonstrated sufficiently clear images in size and shape, which showed that thyroid scintigraphy in small animals should be applicable in examining experimentally produced thyroid diseases.     

Determination of fluorescent diamidines in plasma of experimental animals by high-performance liquid chromatography

The fluorescent diamidines (E)-2,2'-vinylenedi-1-benzo [b] furane-5-carboxamidine dihydrochloride (I) and 2-[2-(6-amidinoindole-2-yl)-(E)-vinyl]-1-benzofurane-5-ca rbo xamidine dihydrochloride (II) were determined in the plasma of experimental animals by high-performance liquid chromatography with a mobile phase of methanol-water (60:40, v/v) containing 0.005 M octanesulphonic acid and 0.003 M dimethyloctylamine. Samples were prepared by precipitation of plasma proteins with methanol-perchloric acid. Quantitation was performed by measuring the peak heights after monitoring the native fluorescence. The assay was linear over the range 5-750 ng/ml for I and 5-500 ng/ml for II, with limits of determination of 2.5 ng/ml for I and 1.5 ng/ml for II. Coefficients of variation were below 10% at all concentrations studied.     

Evaluation of thermal analysis experimental data

The possibilities of the THERMOKIN software package for evaluation of experimental data of solid state thermal decomposition are described. The software package makes it possible to simulate the solid state reactions, to evaluate the results of various thermal analysis methods such as TG/DTG, DSC., evolved gas analysis etc. The software enabled us to choose the adequate model of solid state reactions, to calculate the parameters of reactions and the errors of the parameters. Using this software package the interpretation of the results obtained by various methods of thermal analysis as well as the determination of the optimal experimental conditions for the studied substances can be made.

---

Zusammenfassung Die Möglichkeiten des Softwarepaketes THERMOKIN zur Auswertung experimenteller Daten von thermischen Feststoffzersetzungen werden beschrieben. Das Softwarepaket ermöglicht die Simulation von Feststoffreaktionen, die Auswertung der Ergebnisse von verschiedenen thermoanalytischen Methoden, wie z.B. TG/DTG, DSC., Analyse der entstehenden Gase usw. Durch das Softwarepaket wurde es ermöglicht, ein adäquates Modell für die Feststoffreaktion auszuwählen und die Reaktionsparameter sowie deren Fehler zu berechnen. Unter Anwendung dieses Softwarepaketes können einerseits die Ergebnisse aus den verschiedensten thermoanalytischen Verfahren interpretiert und andererseits die optimalen Reaktionsbedingungen für die jeweiligen untersuchten Substanzen ermittelt werden.

---

---

Dedicated to Prof. Dr. H. J. Seifert on the occasion of his 60^th birthday     

Determination of alpha-tocopherol and alpha-tocopherol acetate in diets of experimental animals. Study of stability in the diets.

A simple method is described which permits, avoiding saponification, alpha-tocopherol and alpha-tocopheryl acetate measurement in semi-synthetic diets for experimental animals by HPLC, with both UV and fluorescence detection. Phenyldodecane was chosen as internal standard with remarkable performances, and EDTA and BHT were added to prevent oxidation in aqueous and non-aqueous phases respectively. The mobile phase was methanol-water (94:6 v/v) at a flow-rate of 2 ml/min. Samples were homogenized and extracted twice with n-hexane by probe sonication. Extracts were evaporated to dryness and redissolved with chloroform-methanol (1:1, v/v). Validation parameters were studied between 25 ng and 6 micrograms for alpha-tocopherol and between 3 and 24.2 micrograms for alpha-tocopheryl acetate, which corresponds to the range of values in the existing diets. Results had correlation coefficients > 0.99; recoveries > 85%; R.S.D. < 6%, so the method is adequate to control vitamin E intake in animals as well as vitamin E stability in food during storage.     

LC-MS characterization of efficacy substances in serum of experimental animals treated with Sophora flavescens extracts

Anti-DHBV (duck hepatitis B virus) activity was found in the aqueous extracts of Sophora flavescens Ait. in vivo. Liquid chromatography/electrospray ionization ion trap mass spectrometry was applied to characterize the components in duck serum after oral administration of S. flavescens extract. Oxymatrine (1), sophoranol (2), sophoridine (3) and matrine (4) were identified in the serum. Further research on the four compounds was evaluated for their antiviral activity against HBV (hepatitis B virus) in cell culture. The results suggested that oxymatrine, sophoranol and matrine were the efficacy substances for anti-HBV activity in aqueous extracts of S. flavescens Ait.     

Evaluation of noisy FIAS using the cross-covariance function

Summary Cross-correlation between FIA-signals and a sequence of rectangular signals reduces analytical noise and improves the limit of decision. This is pointed out by means of simulations and by FIA-AAS.     

Microanalysis of free fatty acids in plasma of experimental animals and humans by high-performance liquid chromatography

A high-performance liquid chromatographic (HPLC) method was developed for microanalysis of thirteen free fatty acids using 200 microliter of plasma. Fatty acids were derivatized with 9-anthryldiazomethane for HPLC analysis. Use of an ODS minicolumn for pretreatment of plasma gave a more accurate determination of free fatty acids in plasma than by chloroform extraction. Using this method, thirteen free fatty acids in the plasma of normal human, dog, rabbit, guinea pig and rat were determined.     

Evaluation of an experimental chemistry preprint server

A preprint is a research article made publicly available prior to formal publication. A preprint server is a freely available archive and distribution medium for preprints, allowing rapid dissemination and use of multimedia and supporting files. Electronic eprints have been widely adopted in certain fields (notably high energy physics), but, until recently, the preprint concept has not been received with enthusiasm by most chemists. Despite the fact that preprints have the advantage of rapid publication, chemists have been reluctant to produce them because they could be viewed as "unallowable" for research assessment or tenure exercises or for publication in certain prestigious journals. In theory, preprints, together with version control and online discussion, could be a useful compromise: rapid prepublication followed by open peer review, before publication in a traditional journal. This paper constitutes a preliminary evaluation of a Chemistry Preprint Server in its second year of operation and summarizes the lessons that can be learned from the experiment to date.     

Plant proteinases and inhibitors: an overview of biological function and pharmacological activity

Proteinases play a fundamental metabolic role during the life cycle in the plant kingdom. By interacting with endogenous or exogenous inhibitors, the proteolytic activity is modulated to meet metabolic requirements. By probing proteolytic enzymes with their inhibitors, it is possible to identify novel functions unrelated to their proteolytic activity. A group of plant proteolytic enzymes stands as a line of defence against environmental changes as their activation is triggered following various types of stress. On the other hand, plants also contain proteinase inhibitors as countermeasures for their protection against insects and pests. Both proteinases and inhibitors emerge as useful tools to combat human diseases. This review focuses on the biochemical characterization of plant proteinases, their inhibitors, the pharmacological potential of proteinases and inhibitors, and new putative emerging functions of proteolytically inhibited proteinases.     

Mentha arvensis essential oil suppressed airway changes induced by histamine and ovalbumin in experimental animals

The present investigation aimed to evaluate the activity of the essential oil of Mentha arvensis L. on exogenously induced bronchoconstriction in experimental animals. The anti-asthmatic effect of M. arvensis essential oil (MAEO) was studied using histamine aerosol-induced bronchoconstriction in guinea pigs and ovalbumin (OVA) sensitised albino mice. Treatment with M. arvensis oil significantly (p < 0.001) increased the time of preconvulsive dyspnoea in histamine-induced guinea pigs. Oral treatment of MAEO significantly (p < 0.001) decreased absolute eosinophil count, serum level of IgE and the number of eosinophils, neutrophils in BALF. Histopathological examination of lungs showed that essential oil rescinded bronchial asthma. The present investigation provides evidence that MAEO relaxes bronchial smooth muscles and suppressed immunological response to OVA.     

The antioxidant response induced by Lonicera caerulaea berry extracts in animals bearing experimental solid tumors

Lonicera caerulea is a species of bush native to the Kamchatka Peninsula (Russian Far East) whose berries have been extensively studied due to their potential high antioxidant activity. The aim of our work was to investigate the in vivo effects of the antioxidant action of Lonicera caerulea berry extracts on the dynamics of experimentally-induced tumors. Our data showed that aqueous Lonicera caerulaea extracts reduced the tumor volume when administered continuously during the tumor growth and development stages, but augmented the tumor growth when the administration of extracts started three weeks before tumor grafting. Prolonged administration of Lonicera caerulaea berry extracts induced the antioxidant defense mechanism in the tumor tissues, while surprisingly amplifying the peripheral oxidative stress.     

Evaluation of vague infrared spectra using the cross-covariance function

Summary The information provided by the ir-spectrum of a mixture-sample to be analyzed can be used at a high level by calculating the cross-covariance function (ccvf) _xy(k) using the ir-spectrum of a reference sample. For qualitative analysis this function is calculated in the wide range of –100xy(k=0) is proportional to the content of the analyte in the sample to be analyzed. Ccvf is calculated only in the range –3相似文献   

Evaluation of antidiabetic and antioxidant potential of lupeol in experimental hyperglycaemia

Oxidative stress, produced under diabetic conditions, is a possible cause of various forms of tissue damage. The concentrations of antioxidant enzymes in cases of diabetes are significantly decreased, with a concomitant increase in lipid peroxidation. In this study, lupeol, a phytoconstituent from Solanum xanthocarpum, is shown to suppress the progression of diabetes after 21 days. Lupeol treatment caused decreases in glycated haemoglobin, serum glucose and nitric oxide, with a concomitant increase in serum insulin level. Furthermore, treatment with lupeol also increased antioxidant levels, with a decrease in the level of thiobarbituric acid-reactive oxygen species.     

Application of prompt activation analysis in the determination of fluorine in tea,in international geochemical standards,bones and teeth of experimental animals

By making use of the ¹⁹F(p,αγ)¹⁶O reaction the F-concentrations of different varieties of tea leaves, of some international geochemical reference materials, and of the bones and teeth of some experimental animals have been determined. The tea leaves from Ceylon (ordinary), Orange Pekoe (special Ceylon), China (ordinary black), Lapsang Souchong (special smoked Chinese) and Darjeeling (India) were found to contain 170 ppm, 170 ppm, 120 ppm, 160 ppm and 100 ppm of fluorine, respectively, The F-concentrations of established geochemical reference materials, NIM-D, NIM-N, NIM-P and NIM-S, from the National Institute of Metallurgy, South Africa were determined to be 60 ppm, 120 ppm, 130 ppm and 190 ppm, respectively. The bones of rabbits, who were given fluoridated water, were found to contain much higher amount of fluorine than the bones of the control rabbit. Furthermore, the rabbits who were kept on fluoridated water for 45 days, had almost double the amount of F in their bones than the rabbits who were given fluoridated water for only 15 days. Similarly, the teeth of grown-up monkeys who were given fluoridated water since birth had double the amount of fluorine than those of the control monkey.     

A possible mechanism of fever induced by Nocardia rubra cell wall skeleton (N-CWS) in experimental animals

The characteristics of fever elicited by the cell wall skeleton of Nocardia rubra (N-CWS) and by lipopolysaccharide (LPS) were compared in rabbits, and the possible involvement of the antigenicity of N-CWS was investigated in guinea pigs. In rabbits, fever of more than 0.5 degree C developed after an intravenous (i.v.) injection of 10 micrograms/kg or more of N-CWS, and was monophasic with 30-100 micrograms/kg but biphasic with the highest dose of 300 micrograms/kg. LPS elicited fever with similar characteristics at doses of 0.01-0.1 microgram/kg. With both compounds, the fever was inhibited by indomethacin. Tolerance to N-CWS and LPS appeared after dosing with 30 or 0.1 micrograms/kg, respectively for 10 d. In guinea pigs sensitized with N-CWS, challenge with 1 or 10 micrograms/kg of N-CWS 10 d later, which did not induce fever in the nonsensitized animals, caused fever of more than 0.5 degree C, and delayed-type hypersensitivity (DTH) appeared. N-CWS also elicited fever in nonsensitized guinea pigs bearing N-CWS-sensitized lymphocytes or anti-N-CWS antibody; the fever was higher in the guinea pigs sensitized with the lymphocytes than in those with the anti-N-CWS antibody. In brief, single injections of N-CWS and of LPS elicited fever with similar characteristics, although the potency of N-CWS was weaker. With N-CWS, the fever is proposed to be triggered by the antigenicity of the compound itself, because doses as low as 1 or 10 micrograms/kg elicited fever along with immunological response in N-CWS-sensitized animals, but not in nonsensitized ones.     

Evaluation of experimental designs for multicomponent determinations by spectrophotometry

Criteria are described and evaluated for choosing an optimal range of wavelengths in multicomponent determinations by spectrophotometry. By using Gaussian curves, results from a systematic study of the effects of resolution and intensity ratios on the performance of these criteria are given. A two-component mixture of 9-methylanthracene and pyrene was used for investigating optimal wavelength ranges and derivative orders. Favorable results were obtained with restricted wavelength ranges offering better spectral characterization for each component. The limit of detection appears to be the most useful criterion.     

Evaluation of the impact of some experimental procedures on different phosphopeptide enrichment techniques

The complete characterization of phosphorylated proteins requires an efficient procedure for the enrichment of phosphopeptides from amongst a complicated peptide mixture. The sensitivity of the traditional immobilized metal affinity chromatography (IMAC) approach is severely affected by various buffers, detergents and other reagents normally utilized in biochemical and cell biological procedures, and thus pre-purification steps such as reversed-phase chromatography is required prior to phosphopeptide enrichment. Here we evaluate the use of different 'non-phosphopeptide-excluding compounds' in the loading buffer for titanium dioxide (TiO(2)) chromatography and show that TiO(2) is more robust and tolerant towards many reagents, including salts, detergents and other low molecular mass molecules, than conventional IMAC. In addition, we show that the inclusion of various detergents can enhance the efficiency of this enrichment method, as phosphopeptides that otherwise adhere to plastic surfaces can be efficiently solubilized and subsequently purified. The TiO(2) chromatography technique is also compared to zirconium dioxide chromatography for phosphopeptide enrichment.