bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fluorometric analysis of urinary chondroitin sulfate isomers by HPLC using dansylhydrazine as a prelabeling reagent
Authors: Shinomiya Kazufusa , Yamanashi Shigeyuki , Imanari Toshio 
Published: May 2005

AbstractChondroitin sulfate isomers (ChS isomers) were digested with chondroitinase ABC, and the unsaturated disaccharides produced were converted into fluorescent dansylhydrazine derivatives and analyzed by HPLC. The proposed method was applied to the determination of relative amounts of ChS isomers in normal human urine and analytical results showed that chondroitin‐6‐sulfate and chondroitin‐4‐sulfate were excreted in large amounts. Moreover, this method was used for the identification of urinary ChS isomers which were extracted from a cellulose acetate strip after carrying out electrophoresis.
High performance liquid chromatographic determination of Picumast and two active metabolites in plasma using on‐line sample preparation
Authors: Besenfelder E. 
Published: May 2005

AbstractA method for determining Picumast, an antiallergic drug, in plasma by HPLC and column switching has been developed. The system consisted of two precolumns, an analytical column, three pumps, an autosampler and a fluorescence detector. The precolumns (17 × 4.6 mm i.d.) were packed with LiChroprep RPR (a moderately polar reversed phase) and the analytical column with Nucleosil ODS (RP 18, 5 μm). The columns were connected according to the alternating precolumn technique. The mobile phase consisted of 30% CH3CN/70% 0.05M KH2PO4, pH 2.5, with a flow gradient. Detection wavelengths were 333 nm for excitation and 383 nm for emission. The retention times of Picumast, M1 and M2 were 12, 3.6 and 4.0 min, respectively. Total run time was 15 min. The limit of detection was 3 ng/mL for M1 and 1 ng/mL for M2 and Picumast using an injection volume of 150 μL. The recoveries vary between 89% and 97% with standard deviations between 2.4 and 3.3%.
Enantiomeric analysis of phenylpropanolamine in plasma via resolution of dinitrophenylurea derivatives on a high performance liquid chromatographic chiral stationary phase
Authors: Doyle Thomas D. , Brunner Charlotte A. , Vick James A. 
Published: May 2005

AbstractRacemic phenylpropanolamine was resolved on a high performance liquid chromatographic (HPLC) chiral stationary phase (CSP) as the 3,5‐dinitrophenyl ureide derivative. The CSP was prepared by a simple in situ procedure in which (R)‐(1‐naphthyl)ethyl isocyanate was bound to aminopropyl silanized silica through a urea linkage. The enantiomeric ureides were prepared by a room‐temperature, 60‐second procedure, accomplishing simultaneous extraction and derivatization and utilizing achiral 3,5‐dinitrophenyl isocyanate as reagent. Baseline resolution was readily achieved under normal phase conditions, with a separation factor (α) of 1.16 and a resolution factor (Rs) of 2.2. Elution was complete within 10 min. A limit of detection, by UV at 235 nm, of 250 pg per isomer was established. Feasibility of the procedure for plasma determinations was demonstrated by assay of samples from a canine subject.
Purification of two murine monoclonal antibodies of the IgM class by hydroxylapatite chromatography and gel filtration
Authors: Henniker A. J. , Bradstock K. F. 
Published: May 2005

AbstractA two‐step method using hydroxylapatite chromatography and gel filtration is described for the purification of two murine monoclonal antibodies of the IgM class. Ascites fluid from each hybridoma was diluted in sodium phosphate buffer (0.01 M, pH 6.8), loaded onto a hydroxylapatite column and eluted with a stepwise sodium phosphate gradient. The immunoreactive protein peaks were concentrated and subjected to gel filtration using either Sephadex G‐200 or Sephacryl S‐200HR. The biological activity of the end‐products was confirmed by complement lysis assay and by indirect immunofluorescence and flow cytometry. The purity of the end‐products as assessed by SDS polyacrylamide gel electrophoresis and densitometry was at least 90%. The methods described produced immunoreactive material with a high level of purity. The procedure for each antibody was reproducible and provides a reliable method for purification of monoclonal antibodies of the IgM class.
Determination of acetazolamide in dosage forms by high performance liquid chromatography
Authors: Gomaa Z. S. 
Published: May 2005

AbstractA high performance liquid chromatographic assay for the quantitation of acetazolamide in both tablet and injection form is described. Acetazolamide is extracted with 0.005 M NaOH solution containing 0.3 mg/mL sulphadiazine (internal standard).A commercially available μ‐Bondapak C18 cartridge column was used for the separation together with a mobile phase made of acetonitrile, methanol and sodium acetate buffer mixture (10:2:88) (pH 4) at a flow‐rate of 4 mL/min. Retention times of about 2.50 and 3.36 min were obtained for the drug and the internal standard, respectively.
Plasma concentrations of β‐carotene, vitamin A and vitamin E after β‐carotene and vitamin E intake
Authors: Postaire E. , Kouyate D. , Rousset G. , Regnault C. , Lati E. , Bejot M. , Gossioux P. , Hazebroucq G. 
Published: May 2005

AbstractWe have studied the metabolism (absorption) of β‐carotene and vitamin E by assigning eleven volunteers to receive daily two capsules of OENOBIOL, each containing 15 mg of β‐carotene and 15 mg of vitamin E, over 60 days. The β‐carotene, vitamin E and vitamin A plasma levels were then determined using new methods developed in our laboratory. After two months, the actively treated group's median β‐carotene and vitamin E levels were significantly higher than those of a control group. However, no significant change between treated and control groups in the mean of vitamin A (retinol) plasma levels were observed. Treatment with β‐carotene, a vitamin A precursor, does not significantly modify the vitamin A levels. This conclusion had already been observed and it is assumed that a plasma level of β‐carotene equal or higher than 0.3 mg/L reflects a nutritional intake of provitamins sufficient to support homeostasis of retinol (Brubacher et al., 1982).
Separation of human pancreatic carboxypeptidase A isoenzymes by high performance liquid chromatography
Authors: Linder D. , Linder M. , Schade H. , Sziegoleit A. 
Published: May 2005

AbstractHuman pancreatic carboxypeptidase A, which was isolated from a pool of necrobiotic pancreae, crystallized spontaneously and appeared homogeneous in sodium dodecylsulphate polyacrylamide gel electrophoresis. Reversed phase high performance liquid chromatography of the dissolved crystals, however, revealed the presence of two distinct isoenzymes, which were shown by aminoterminal sequence analysis to be only 61% homologeous in their 31 amino terminal amino acids. On the other hand, amino terminal sequences of the isoenzymes were found to be 79% and 87% homologeous with CAP 1 and CPA 2 of the rat, respectively. Thus, the presence of two distinct pancreatic carboxypeptidase A isoenzymes could be clearly demonstrated for the first time in human tissue.
Purity evaluation of aprotinin by high performance liquid chromatography
Authors: Dimov N. , Simeonov S. 
Published: May 2005

AbstractA separation to the baseline isocratic technique has been developed for the evaluation of the purity of aprotinin by internal normalization. The column used was a 30 nm pore diameter butyl‐bonded silica stationary phase. An exact relationship was found to give an adequate description of the retention of aprotinin using acetonitrile concentrations of 17–22% and NaCIO4 concentrations of 5–50 mmol. It can be used to optimize the mobile phase content for the particular user column and to compensate for possible variations in the retention time of aprotinin, analysed on different batches of butyl‐bonded stationary phases.
Determination of 5,10,15,20‐tetra‐(m‐hydroxyphenyl) chlorin in tissues by high performance liquid chromatography
Authors: Wang Qiang , Altermatt H. J. , Ris H.‐B. , Reynolds Brenda E. , Stewart J. C. M. , Bonnett R. , Lim C. K. 
Published: May 2005

AbstractA procedure for the extraction and high performance liquid chromatographic (HPLC) determination of the photodynamic therapeutic agent 5,10,15,20‐tetra(m‐hydroxyphenyl)chlorin in human, rat and mouse tissues following intravenous administration of the drug is described. The tissue (tumour, skin, muscle and liver) was homogenized and extracted into a mixture of methanol:dimethyl sulphoxide:water (32:8:1 by vol.) containing, 5,10,15,20‐tetra(p‐hydroxyphenyl)chlorin as the internal standard. The precipitated proteins were removed by centrifugation and the supernatant was separated by reversed phase HPLC on a Hypersil‐ODS column with 77% (v/v) acetonitrile in 0.1% trifluoroacetic acid as the mobile phase. The solute was detected with high sensitivity and specificity by a UV‐VIS detector set at 423 nm.
FT‐IR spectroscopic studies on molecular interactions of cryoprotectant agents with bacteria
Authors: Zeroual Widad , Millot Jean Marc , Choisy Claude , Manfait Michel 
Published: May 2005

AbstractFourier transform infrared spectroscopy was used to investigate, without any destructive interference, interactions of the cryoprotective agents, glycerol and dimethyl sulfoxide withBradyrhizobium japonicum. The intracellular spectrum of glycerol, obtained by subtracting the spectrum of control bacteria from that of glycerol‐treated bacteria, showed no differences in infrared features compared to that of pure glycerol. This was not the case when dimethyl sulfoxide treatment was used. The intracellular spectrum displayed important modifications compared to that of the pure chemical. Spectral analysis showed that glycerol and dimethyl sulfoxide uptake required only a few minutes. Moreover, the infrared features resulting from the presence of pure glycerol, in bacteria, were still existent for up to 2 or 3 hours after thawing process. The deconvoluted Amide I and Amide II bands of bacterial proteins reflected important changes in secondary structure after treatment of bacteria with dimethyl sulfoxide (increase in β‐sheet and loss of random coil content). In contrast to glycerol, the cryoprotective action of dimethyl sulfoxide probably involves interactions with a wide range of intrabacterial species. © 1995 John Wiley & Sons, Inc.
Haemosiderin and tissue damage
Authors: Weir Malcolm P. , Gibson John F. , Peters Timothy J. 
Published: May 2005

AbstractHigh levels of haemosiderin occur in iron overload syndromes such as idiopathic haemochromatosis or secondary iron overload in thalassaemic patients; haemosiderin is the predominant iron‐storage compound in such cases. It consists of a large aggregate of FeOOH cores, many of which have an incomplete shell of protein, and is probably derived from ferritin by lysosomal proteolysis. In addition, some chemical degradation of the ferritin cores appears to occur on conversion to haemosiderin. Other biochemical components are phosphate and magnesium, which may be adsorbed to the core surface, and perhaps certain lipids. Haemosiderin may have a central role, either directly or indirectly, in iron cytotoxicity and therefore the chemistry and biochemistry of this material warrants further study.
The Clara cell and pulmonary surfactant: A study using selective chemical ablation
Authors: Cottrell R. C. , Foster J. R. , Pelling D. , Herod I. A. , Lee V. S. , Purchase R. , Bayley D. , Miller K. 
Published: May 2005

AbstractAdministration of 3‐hydroxymethylfuran‐N‐ethylcarbamate (HFC) to female hamsters via the jugular vein under pentobarbitone anaesthetic at 20 mg per kg body weight produced pronounced necrosis of the Clara cells without apparent morphological effect on other cell types as judged by transmission electron microscope examination. The surfactant material recoverable by minimal lavage followed by purification by sucrose gradient ultracentrifugation increased, reaching a maximum around 48 h after treatment. At this time static pressure/volume measurements on isolated lungs indicated an increase in airway surface compliance. Lavageable surfactant phospholipid composition was examined by 31P nuclear magnetic resonance (n.m.r.). The distribution of phospholipids between the various classes was unchanged by HFC treatment. No change in the total lung surfactant pool size was seen. These results are discussed in relation to the possible roles of the Clara cell in influencing airway surfactant levels.
Localization of putative gonadotrophin releasing hormone receptor protein in the anterior pituitary
Authors: Zolman Joseph C. , Theodoropoulos Theodor J. 
Published: May 2005

AbstractSpecific binding of a fully biologically active 125I‐gonadotrophin releasing hormone (GnRH) to isolated anterior pituitary cells is time dependent, saturable and the concentration dependent binding curves exhibit positive cooperativity. Binding to intact or solubilized plasma membranes and an affinity purified GnRH receptor protein reveals in all instances multiple high affinity binding sites. Thus, GnRH receptor protein appears to be an intrinsic constituent of the cell membrane, and perhaps, other membranous organelles. To investigate the latter, the binding of 125I‐GnRH to various subcellular fractions was studied and its affinity and time requirements determined. GnRH binding to plasma membranes and secretory granules was to multiple high affinity sites, while that to nuclei and microsomes was to a single high affinity site. Binding was 1.83 ± 0.07, 0.78 ± 0.04, 0.31 ± 0.03 and 0.27 ± 0.03 fmol μg−1 protein for isolated plasma membranes, secretory granules, microsomes and nuclei, respectively, after 30 min incubation with 10−9 M GnRH. The magnitude of binding to microsomes did not change during the incubation period. It did not show any decrease (p > 0.5) in isolated nuclei and plasma membranes, except for the 24 h time period, when a significant drop (p < 0.001) was seen. Binding to the secretory granule fraction culminated at 15 min and then decreased (p < 0.001) steadily to a non‐detectable level at 24 h. Thus GnRH receptor protein or its portion may be an integral part of some membranous particles in the anterior pituitary cells. A single, low‐capacity binding site may, or may not suggest the presence of a structurally incomplete form of the receptor protein in microsomes and nuclei. Binding to the secretory granules fraction exhibited only a relatively minor temporal difference compared to the plasma membrane, which may have resulted from an inappropriate conformational state of the receptor protein. Only the binding to the plasma membrane exhibited appropriately both the affinity and temporal requirements of the intact GnRH receptor protein in vitro and in vivo.
In vitro trophic effects of synthetic ACTH1–24
Authors: Jolink D. , Drexhage H. A. , van der Gaag R. D. 
Published: May 2005

AbstractIn vitro trophic effects of adrenocorticotrophin1–24 (ACTH1–24, Synacthen) on adrenal cells were studied, using an in vitro assay system of guinea‐pig adrenal segments kept in organ culture. Two separate methods for detecting growth activity were used, namely the measurement of thymidine kinase and a nucleic acid cytophotometric method. Synthetic ACTH was able to induce growth in the adrenal explants at very low concentrations (10–25 fg ml−1). Biphasic dose‐response curves were obtained, comparable to those described for other cytochemical bioassays. The principles of this assay system may allow the development of a new bioassay for the measurement of plasma concentrations of ACTH or antibodies mimicking the growth effect of this trophic hormone.
Scanning cytophotometric analysis of myocardial nucleic acid and chromatin changes in soman toxicated rabbits
Authors: Martin Lee J. , Doebler Jeffrey A. , Swisher John W. , Anthony Adam , Shih Tsung‐Ming 
Published: May 2005

AbstractMyocardial nucleic acid responses were analysed in New Zealand White rabbits 20 min–1 h and 6–8 h following single subcutaneous injections of soman (20, 30, or 40 μg kg−1). Scanning‐integrating microdensitometry was used to quantify Azure B‐RNA and Feulgen–DNA (F‐DNA) levels, and changes in the suseptibility of chromatin to Feulgen acid hydrolysis (F‐DNA reactivity) of individual ventricular myocardial cells. With a dosage of 20 μg kg−1 soman, no RNA alterations were evidenced at 1 h whereas at 6–8 h myocardial cells exhibited higher RNA levels and an increase in F‐DNA reactivity of chromatin. With dosages of 30 and 40 μg kg−1 soman there was an augmentation in RNA levels and in the acid hydrolysability of nuclear chromatin at both 20 min–1 h and 6–8 h. It is postulated that the observed cellular transformations represent a compensatory augmentation in myocardial metabolic functioning presumably in response to an increased functional demand on the ventricular myocardium. The absence of cytopathic or cytochemical evidence of impairment in nucleic acid metabolism is inconsistent with the premise that soman exerts direct cytotoxic effects on rabbit myocardium.
Synthesis and levels of organic phosphates in erythrocytes during avian development: Specific formation of BPG and IP5 in two distinct populations from young chicks
Authors: Ruiz‐Ruano A. , Martin M. , Luque J. 
Published: May 2005

AbstractTwo generations of red cells (embryonic and definitive), different types of haemoglobins, and special organic phosphates involved in the control of haemoglobin oxygenation (2:3‐bisphosphoglycerate, BPG, and inositol‐5‐phosphate, IP5), have been found progressively during development of the chick. Levels of both organic phosphates, as well as activities of the enzymes involved in BPG synthesis (2:3‐bisphosphoglycerate synthase, BPGM) and IP5 formation (phytase), were studied in the erythrocyte populations from embryo, young and adult chickens. Measurement of specific activities of BPGM and phytase in the two subpopulations present in young chickens showed that these phosphates could be specifically and predominantly formed in these two red cell populations.
Induction of cytochrome(s) P450‐dependent drug metabolism in cultured MH1C1 hepatoma cells
Authors: Ferro Margherita , Bassi Anna M. , Marinari Umberto M. , Nanni Giorgio , Chiarpotto Elena , Poli Giuseppe , Dianzani Mario U. 
Published: May 2005

AbstractA cell line derived from a Morris hepatoma, MH1C1, was examined for its in vitro expression of monooxygenases. These cells were found to contain different forms of cytochrome P450, as shown by the response to inducers, namely phenobarbital (PB), 3‐methylcholanthrene (MC) and metyrapone (MP). MH1C1 cell monolayers exposed to PB or MC showed an increase in the concentration of two spectrally distinct forms of cytochrome P450. The PB and MC treatments elicited enzyme activities towards the substrates aminopyrine and benzo(a)pyrene, respectively. The cell treatment with metyrapone led to a simultaneous stimulation of aminopyrine demethylase and benzo(a)pyrene hydroxylase activities, so underlining the peculiar features of this inducer.
Cell cycle effects of hypertonic stress on various human cells in culture
Authors: Pellicciari C. , Filippini C. , De Grada L. , Conti A. M. Fuhrman , Romanini M. G. Manfredi 
Published: May 2005

AbstractLong‐term exposure to hypertonic (HT) culture media has been found to perturb the cell cycle and change gene expression in various animal cell types. A lower growth rate, with exit of cells from the cycling compartment has been observed previously in human transformed EUE. cells. The aim of this study was to investigate if the kinetic changes after long‐term HT stress, were typical of transformed cells or could be also found in primary cultures of normal cells. Human transformed cells from normal and neoplastic tissues, and normal human cells of epithelial and connective origin have been studied. After the incorporation of bromodeoxyuridine (BrdUrd), the frequency of S‐phase cells was estimated by dual‐parameter flow cytometry of DNA content versus BrdUrd immuno‐labelling; the total growth fraction was also estimated, after immunolabelling with an anti‐PCNA antibody. We also investigated, by polyacrylamide gel electrophoresis, changes in the amount of a 35 kDa protien band, which increased in EUE cells grown in an HT medium, and which may be directly involved in cell resistance to hypertonicity. Lower BrdUrd labelling indices and higher frequencies of cells in the G0/1 range of DNA content were common features of all the cells in HT media, irrespective of their tissue of origin; other cycle phases may also be involved, depending on the cell type considered. The mechanisms by which cells cope with the HT environment could however, differ, since only some cell types showed an increase of the 35 kDa stress protein found originally in HT EUE cells.
Effects of choline and ethanolamine on the synthesis and breakdown of the inositol phospholipid (PI) system in Tetrahymena
Authors: Kovács P. , Csaba G. 
Published: May 2005

AbstractLower concentrations of choline chloride and ethanolamine (10−3 M; 10−5 M) increased phosphatidyl inositol (PI), phosphatidyl inositol monophosphate (PIP) and phosphatidyl inositol bisphosphate (PIP2) level of Tetrahymena, while higher concentrations (10−2 M) decreased them. These two substances also influenced, however in a less obvious way, the transformation of inositol phospholipids. The experiments draw attention to the sensitivity of the precursors of the second messenger system at a phylogenetically low level.
Real‐time filtering of data from mobile, passive remote infrared sensors with principal component models of background
Authors: Brown S. D. 
Published: May 2005

AbstractReal‐time monitoring of pollutant levels from a mobile measuring platform requires fast, flexible data analysis methods. This paper reports a method for rapid analysis of passive remotely sensed infrared data with the aid of a Kalman filter. The background spectra produced by emission from the atmosphere are modelled at the start of the data collection sequence with a simple principal components model obtained by eigenanalysis of the initial ‘blank’ data taken with the spectrometer. The species of interest are included in the state space model by a separate measurement of their infrared spectra. It is demonstrated that for best filter performance in detecting the simulated pollutant species SF6 in the atmosphere, a filter model with two principal components describing the emission background works best. The filter ‘maps’ of SF6 closely follow the integrated spectral intensities measured after removal of suitable backgrounds.
Expectation–maximization algorithm for regression, deconvolution and smoothing of shot‐noise limited data
Authors: Bialkowski S. E. 
Published: May 2005

AbstractA simple algorithm for deconvolution and regression of shot‐noise‐limited data is illustrated in this paper. The algorithm is easily adapted to almost any model and converges to the global optimum. Multiple‐component spectrum regression, spectrum deconvolution and smoothing examples are used to illustrate the algorithm. The algorithm and a method for determining uncertainties in the parameters based on the Fisher information matrix are given and illustrated with three examples. An experimental example of spectrograph grating order compensation of a diode array solar spectroradiometer is given to illustrate the use of this technique in environmental analysis. The major advantages of the EM algorithm are found to be its stability, simplicity, conservation of data magnitude and guaranteed convergence.