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At least 1,189 records · Page 66Linked to original sources
PubMed2003

Garlic attenuates chrysotile-mediated pulmonary toxicity in rats by altering the phase I and phase II drug metabolizing enzyme system.

Asbestos and its carcinogenic properties have been extensively documented. Asbestos exposure induces diverse cellular events associated with lung injury. Previously, we have shown that treatment with chrysotile shows significant alteration in phase I and phase II drug metabolizing enzyme system. In this study we have examined some potential mechanisms by which garlic treatment attenuates chrysotile-mediated pulmonary toxicity in rat. Female Wistar rats received an intratracheal instillation of 5 mg chrysotile (0.5 mL saline) as well as intragastric garlic treatment (1% body weight (v/w); 6 days per week). Effect of garlic treatment was evaluated after 1, 15, 30, 90, and 180 days by assaying aryl hydrocarbon hydroxylase (AHH), glutathione (GSH), glutathione S-transferase (GST), and production of thiobarbituric acid reactive substances (TBARS) in rat lung microsome. The results showed that AHH and TBARS formation were significantly reduced at day 90 and day 180 in chrysotile treated garlic cofed rats; GSH recovered 15 days later to the near normal level and GST elevated significantly after treatment of garlic as compared to chrysotile alone treated rat lung microsome. The data obtained shows that inhibition of AHH activity and induction of GST activity could be contributing factor in chrysotile-mediated pulmonary toxicity in garlic cofed rats. However, recovery of GSH and inhibition of TBARS formation by garlic and its constituent(s) showed that garlic may give protection by altering the drug metabolizing enzyme system.

Animals↗
PubMed2006

Correlation between computed gas-phase and experimentally determined solution-phase infrared spectra: models of the iron-iron hydrogenase enzyme active site.

Gas-phase density functional theory calculations (B3LYP, double zeta plus polarization basis sets) are used to predict the solution-phase infrared spectra for a series of CO- and CN-containing iron complexes. It is shown that simple linear scaling of the computed C--O and C--N stretching frequencies yields accurate predictions of the the experimentally determined nu(CO) and nu(CN) values for a variety of complexes of different charges and in solvents of varying polarity. As examples of the technique, the resulting correlation is used to assign structures to spectroscopically observed but structurally ambiguous species in two different systems. For the (mu-SCH2CH2CH2S)[Fe(CO)3]2 complex in tetrahydrofuran solution, our calculations show that the initial electrochemical reduction process leads to a simple one-electron reduced product with a structure very similar to the (mu-SCH2CH2CH2S)[Fe(CO)3]2 parent complex. For the iron-iron hydrogenase enzyme active site, our computations show that the absence or presence of a water molecule near the distal iron center (the iron center further from the [4Fe4S] cluster and protein backbone) has very little effect on the predicted infrared spectra.

Binding Sites↗
PubMed2001

Comparison between solution-phase stability and gas-phase kinetic stability of oligodeoxynucleotide duplexes.

The relative kinetic stabilities of different 16-mer oligonucleotide duplexes were investigated by source collision-induced dissociation (CID) in a heated capillary electrospray ion source. They were compared with the relative stabilities in solution obtained by thermal denaturation monitored by UV spectrophotometry. The results clearly show that both hydrogen bonding and base stacking interactions that are present in solution are maintained in the gas phase. This suggests that the electrospray process preserves the double-helix structure of DNA. A step by step opening of the double helix structure is proposed for the gas-phase dissociation, competing with the covalent bond cleavage of bases. We also draw attention to the fact that by source CID, it is the kinetic stability of the complexes that is probed. In particular, this implies that only complexes of the same size can be compared.

Base Sequence↗
PubMed1981

Application of one-phase end-point change system in two-phase titration to amine drug analysis.

A titration method was developed for the determination of diphenhydramine, quinine, neostigmine, sparteine, strychnine, homatropine, atropine, physostigmine, and procaine in aqueous solution. Tetraphenylborate was used as a titrant with tetrabromophenolphthalein ethyl ester as an indicator in the presence of organic solvent. End-point detection was based on the color change of the indicator in the organic phase without movement of the indicator from one phase to the other.

Amines↗
PubMed1988

Determination of fat-soluble vitamins in a pharmaceutical dosage form by solid-phase extraction and reversed-phase liquid chromatography.

A rapid and precise method for the determination of fat-soluble vitamins from a water-based multivitamin mixture was developed utilizing solid-phase extraction and reversed-phase high-performance liquid chromatography (HPLC). Cholecalciferol, alpha-tocopherol acetate, and retinol palmitate were extracted in a single stage from the matrix using Bond Elut C18 columns. The vitamins were then chromatographed on a Hypersil 5-microns C18 column, using a water:methanol gradient, and quantified simultaneously using individual UV absorption maxima. The recovery of added analytes varied from 92.6 to 100.6%. The assay coefficient of variation was 1.7-2.7%. The sample preparation method and HPLC assay described here are practical for pharmaceutical quality control purposes.

Cholecalciferol↗
PubMed2004

Artifact suppression in imaging of myocardial infarction using B1-weighted phased-array combined phase-sensitive inversion recovery.

Regions of the body with long T1, such as cerebrospinal fluid (CSF), may create ghost artifacts on gadolinium-hyperenhanced images of myocardial infarction when inversion recovery (IR) sequences are used with a segmented acquisition. Oscillations in the transient approach to steady state for regions with long T1 may cause ghosts, with the number of ghosts being equal to the number of segments. B1-weighted phased-array combining provides an inherent degree of ghost artifact suppression because the ghost artifact is weighted less than the desired signal intensity by the coil sensitivity profiles. Example images are shown that illustrate the suppression of CSF ghost artifacts by the use of B1-weighted phased-array combining of multiple receiver coils.

Artifacts↗
PubMedDate not supplied

Solid-phase extraction and reversed-phase high-performance liquid chromatography of the five major alkaloids in Narcissus confusus.

A novel, fast and precise method, combining solid-phase extraction and reversed-phase high-performance liquid chromatography is described for the quantitative determination of five alkaloids (galanthamine, N-formylnorgalanthamine, haemanthamine, homolycorine and tazettine/pretazettine) from bulbs of wild Narcissus confusus, a high galanthamine-containing plant species growing in the Iberian Peninsula.

Alkaloids↗
PubMed2001

Isoelectric focusing nonporous silica reversed-phase high-performance liquid chromatography/electrospray ionization time-of-flight mass spectrometry: a three-dimensional liquid-phase protein separation method as applied to the human erythroleukemia cell-line.

A liquid-phase three-dimensional protein separation method has been developed that is used to separate the cytosolic fraction of a HEL cell lysate via isoelectric focusing (IEF), nonporous silica (NPS) reversed-phase high-performance liquid chromatography (RP-HPLC) and electrospray ionization time-of-flight mass spectrometry (ESI-TOFMS), respectively. Several hundred unique protein molecular weights were observed in a pI range from 4.8 to 8.5 and a mass range from 5 to 85 kDa. Proteins were positively identified by analysis of the pI (+/-0.5 pI units), an intact protein molecular weight (+/-150 ppm), and peptide mass mapping results. Using the molecular weight (MW) and peptide mapping results of identified proteins it was possible to characterize their posttranslational (PTMs) and/or sequence modifications. PTMs were detected on both forms of cytosolic actin, heat shock 90 beta, HINT and alpha-enolase. Sequence modifications or conflicts were observed for beta-and gamma-actin, ATP beta-synthase and heat shock 90 beta. IEF-NPS-RP-HPLC/ESI-TOFMS was used to determine experimental pI, MW and relative hydrophobicity values for each protein detected. This data was used to generate a 2-D pI-MS protein map, where proteins are displayed according to their pI and molecular weight. Protein molecular weight peaks are represented as bands in the 2-D pI-MS image where the gray scale of each band is proportional to the intensity of the protein molecular weight peak. In addition, a third hydrophobicity dimension (%B) was added as the % acetonitrile elution to generate a 3-D pI-MS-%B plot where each protein can be tagged according to three parameters.

Amino Acid Sequence↗
PubMed2002

Determination of chiral ratio of o,p-DDT and o,p-DDD pesticides on polysaccharides chiral stationary phases by HPLC under reversed-phase mode.

A simple and reliable HPLC method for the chiral resolution of o,p-DDT and o,p-DDD is described. The enantiomeric resolution of o,p-DDT and o,p-DDD has been achieved on Chiralpak AD-R, Chiralcel OD-R, and Chiralcel OJ-R chiral stationary phases. The mobile phases used were acetonitrile-water (50:50 [v/v]) and acetonitrile-2-propanol (50:50 [v/v]) at a flow rate of 1.0 mL/min. For both pesticides detection was done at 220 nm. The values for o,p-DDT of alpha and R(s) varied from 1.24 to 2.52 and from 0.80 to 2.47, respectively. The values of alpha and R(s) for o,p-DDD were 1.26 and 0.60, respectively.

Antineoplastic Agents, Hormonal↗
PubMed1999

Activity of phase I and phase II detoxication enzymes in different cormus parts of Phragmites australis.

Enzymes of phase I and phase II of the xenobiotic detoxication pathway (ethoxyresorufin-O-deethylase, peroxidases, microsomal and soluble glutathione-S-transferases) were measured in roots, stems, and leaves of Phragmites australis, revealing different enzyme activities in these parts. Highest enzyme activities were measured in the root followed by the leaf. Enzyme activities detected in the stem were low compared with those in the root and leaf. The high detoxication capacity of the root and the leaf might be due to very high exposure to xenobiotics and to the high levels of metabolism in these cormus parts. The function of the stem of Phragmites is mainly transportation, so a high detoxication level is not useful, as indicated by the low enzyme activities.

Cytochrome P-450 CYP1A1↗
PubMed1997

H-aggregation of Methyl Orange at the Interface between the Water Phase and Oil Phase in a Water-in-Oil Microemulsion

Methyl orange dissolved in a water-in-oil microemulsion was examined by UV-VIS absorption spectroscopy and differential scanning calorimetry (DSC). Methyl orange showed two temperature-dependent peaks at 416 and 354 nm in the microemulsion. The former was attributed to a methyl orange monomer, and the latter to aggregates of the dye in the parallel orientation (H-aggregates) at the interface between the water phase and the oil phase in the microemulsion. The position of methyl orange in the microemulsion was verified by DSC analysis.

Journal Article↗
PubMed1997

Order of Three-Phase (Solid-Liquid-Gas) Contact Line Tension Probed by Simulation of Three-Phase Contact Line Expansion on Small Hydrophobic Spheres

Expansion of the three-phase (solid-liquid-gas) contact line on the surface of silanated glass spheres was experimentally studied by means of a CCD high-speed video technique. The dependence of the central angle (measured at the particle center) of the contact line on time was determined. This dependence was theoretically simulated. Results of this simulation show a strong effect of line tension on the kinetics of the three-phase contact expansion. Order of the line tension (&mgr;J/m) is the same as that determined by A. W. Neumann and co-workers for similar hydrophobic surfaces by means of different techniques.

Journal Article↗
PubMed1985

Phase-I study of mafosfamide-cyclohexylamine (ASTA-Z-7557, NSC 345 842) and limited phase-I data on mafosfamide-lysine.

Mafosfamide-cyclohexylamine is a new oxazaphosphorine derivative. It was chosen for phase-I clinical testing because of an expected higher therapeutic index and lack of complete cross resistance in animal tumors compared to cyclophosphamide. The schedule consisted of a single iv dose repeated every three weeks. The compound was found to cause as it's dose limiting toxicity severe pain along the injected vein and acute irritation of mucous membranes. The maximal tolerated dose was around 1000 mg/m2 given as a slow infusion over 2-3 hours. Hematological toxicity was mild. A limited phase-I study with the lysine salt of mafosfamide showed an identical type of toxicity. Mafosfamide given iv in a high-dose intermittent schedule is of little interest for further clinical trials. It is probable, that the severe venous pain and the mucosal irritation are caused by the high local concentration of 4-hydroxy-cyclophosphamide or by a metabolite. An oxazaphosphorine derivative undergoing slower hydrolysis therefore leading to lower active drug concentrations within the injected vein may be more promising.

Adult↗
PubMed1987

Posttreatment with sodium arsenite is coclastogenic in log phase but not in stationary phase.

Posttreatment with sodium arsenite in log phase synergistically increases the chromosomal aberrations induced by ethyl methanesulfonate in Chinese hamster ovary cells, human fibroblasts, and human lymphocytes. However, posttreatment with sodium arsenite in stationary phase has no apparent effect on the clastogenicity of ethyl methanesulfonate. These results indicate that the cycling state of the cell plays a crucial role in the action of arsenite coclastogenicity. One prediction from this finding is that in combined treatment, posttreatment with sodium arsenite should preferentially kill cancer cells.

Animals↗
PubMed2000

The value of in-phase and opposed-phase T1-weighted breath-hold FLASH sequences for hepatic imaging.

The value of the combined in-phase (IP) and opposed-phase (OP) T1-weighted (T1-W) breath-hold FLASH sequences for hepatic imaging, especially for fat content, was evaluated. Non-contrast-enhanced IP and OP T1-W GRE breath-hold images were obtained in 76 patients refereed for abdominal MRI at 1.5T. 76 patients were divided into three groups for analysis: (1) liver without mass (n = 8); (2) liver with hepatoma (n = 34); (3) liver with haemangioma or cyst (n = 34). Liver/spleen and liver/lesion signal-to-noise (SNR) and contrast-to-noise ratio (CNR) were assessed for lesion detection. Images between IP and OP sequences were compared quantitatively. The results showed that there was not statistically significant difference in liver/spleen and liver/lesion SNR between IP and OP sequences. In the patients with fatty infiltration, the OP sequences yielded substantially lower values for liver/spleen and liver/lesion SNR than those of the IP sequences. Furthermore, OP imaging showed fatty infiltration in 14 cases and demonstrated hyperintense peritumor rim in 4 cases. In 14 cases of fatty infiltration, many lesions were identified using IP images. The use of IP and OP GRE sequences provides complementary diagnostic information for hepatic lesions and fat content. Focal hepatic lesions may be obscured in the setting of fatty infiltration if only OP sequences are employed. A complete assessment of the liver with MR should include both IP and OP imaging.

Adolescent↗
PubMed2005

Distinct different intra-tumor distribution of FDG between early phase and late phase in mouse fibrosarcoma.

An early image of intra-tumor distribution of 14C-labeled fluorodeoxy glucose (14C-FDG) was compared with a late image of 18F-labeled FDG (18F-FDG) using mouse fibrosarcoma. Heterogeneous intra-tumor distribution of 14C-FDG was observed 1 minute post injection of the tracer, whereas relatively homogeneous distribution of 18F-FDG was seen 30 minutes later. 14C-FDG was particularly taken up in the peripheral part of the tumor immediately after the tracer injection. A gradual and significant increase in 18F-FDG accumulation with time was seen in the central part of tumor, which indicated an enhancement of anaerobic glycolysis. An initial uptake of 18F-FDG was also compared with distribution of 14C-iodoantipyrine and 14C-thymidine uptake. Intratumoral distribution of initial uptake of 18F-FDG showed almost the same regional distribution of 14C-iodoantipyrine. A similar distribution of 14C-thymidine as the initial uptake of 18F-FDG was also observed. These results indicated that a high initial FDG uptake area seemed to be highly proliferative. A significant difference in the intratumoral distribution of FDG between early phase and late phase seemed to be related to heterogeneous biological characteristics of tumor cells.

Animals↗
PubMed2001

Miniaturized fiber-in-tube solid-phase extraction as the sample preconcentration method for microcolumn liquid-phase separations.

Miniaturized fiber-in-tube solid-phase extraction (fiber-in-tube SPE) has been developed as a solventless sample preconcentration technique for microcolumn liquid-phase separation methods. Short capillaries packed with polymer filaments were employed as the extraction tube and the preconcentration power for phthalates in aqueous solutions was studied. On the basis of the successful on-line coupling of this preconcentration method with liquid chromatography (LC), a more miniaturized extraction cartridge, which is installed in the rotor of the micro-injector, has been developed. With a modified commercially available valve, on-line coupling of this sample preconcentration method to capillary electrochromatography (CEC) was also investigated.

Journal Article↗
PubMed2001

Determination of hydrogen ion by ion chromatography (IC) with sulfonated cation-exchange resin as the stationary phase and aqueous EDTA (ethylenediamine-N,N,N',N'-tetraacetic acid) solution as the mobile phase.

An ion chromatographic (IC) method has been developed for determination of hydrogen ion (H+). It is based on the use of sulfonated cation-exchange resin as stationary phase, aqueous ethylenediamine-N,N,N',N'-tetraacetic acid (dipotassium salt, EDTA-2K, written as K2H2Y) solution as mobile phase, and conductivity for detection. H+ was separated mainly by cation-exchange, but its elution was accelerated by the presence of EDTA. The order of elution for the model cations was H+ > Li+ > Na+ > NH4+ > Ca2+ > > Mg2+. A sharp and highly symmetrical peak was obtained for H+ and this was attributed to the capacity of H2Y2(2-) to receive and bind H+. H+ was detected conductiometrically and detector response (reduction in conductivity as a result of H+ +H2Y2- --> H3Y-) was linearly proportional to the concentration of H+ in the sample. The detection limit for H+ with this IC system was better than 4.7 micromol L(-1). A significant advantage of this method was the ability to separate and determine, in one step, H+ and other cations. The successful determination of H+ and other cation species in real acid-rain samples demonstrated the usefulness of this method.

Acid Rain↗