Determination of recombinant human epidermal growth factor (rhEGF) in a pharmaceutical preparation by capillary electrophoresis

A simple assay method of recombinant human epidermal growth factor (rhEGF) in a pharmaceutical preparation was studied and validated by capillary electrophoresis (CE) using micellar electrokinetic chromatography (MEKC) techniques. Factors affecting the migration behavior and separation performances of the peptide; type of buffer, pH, buffer concentration, and concentration of sodium dodecyl sulfates (SDS) were investigated to optimize the analytical performance. CE was performed using running buffer, 50.0 mM borate (pH 8.5) containing 12.5 mM SDS at 20 kV of the applied voltage. Calibration curves for the rhEGF showed good linearity (r>0.999) over the wide dynamic range from 1.25 to 100 microg/ml. Sample analysis was performed by using standard addition method to eliminate the matrix effects of dosage vehicle. This method is assumed to be useful for quality control (QC) of various forms of pharmaceutical products of the peptide.

Determination of recombinant human epidermal growth factor (rhEGF) in a pharmaceutical formulation by high performance liquid chromatography with electrochemical detection

A novel HPLC method with electrochemical detection has been developed for the determination of recombinant human epidermal growth factor (rhEGF) in pharmaceutical products. rhEGF was separated from other components in formulation on a reversed-phase C18 column with 24% acetonitrile in 0.1 M phosphate buffer (pH 4.75). The optimum electrochemical oxidation of EGF was obtained at 0.85 V vs. Ag/AgCl in a glassy carbon working electrode due to electroactive tyrosine, tryptophan, methionine, and arginine residues. The quantitation range was from 1.0 to 200 ng of rhEGF with the linear correlation coefficient greater than 0.999. The method was successfully applied for the quantitation of rhEGF in a pharmaceutical preparation.

Sphingolipid metabolic changes during chiral C2-ceramides induced apoptosis in human leukemia cells

N-acetylsphingosine (C2-ceramide) is a synthetic water-soluble ceramide mimicking the activity of natural ceramides. By fixing chiral conformation on carbon numbers 2 and 3 in the ceramide structure, four chiral C2-ceramides naming d-erythro-, l-erythro-, d-threo- and l-threo C2-ceramide were synthesized. We have investigated the chiral effects of these C2-ceramides on the sphingolipid metabolism, particularly on both the sphingolipid biosynthetic pathway and on the degradation pathway. In both HL-60 and U937 cells, the chiral C2-ceramide (10 microM) showed sphingosine accumulation monitored fluoromatrically by a high performance liquid chromatographic separation of the sphingoid bases. Most importantly, in HL-60 cells, l-erythro C2-ceramide induced a 50 fold increase in sphingosine as compared to the control, while l-threo C2-ceramide exhibited a minimal 7-fold increase. In contrast, sphinganine, another sphingoid base, showed less accumulation by any chiral C2-ceramide tested under the same conditions. These results suggested that chiral C2-ceramide primarily acts on the sphingolipid degradation pathway rather than on the sphingolipid biosynthetic route. The strong G0/G1 phase arrest in the cell cycle by treatment of l-erythro C2-ceramide indicates that the blockade of the sphingolipid degradation pathway might be concomitantly involved in the dysfunction of the cell cycle. On the other hand, the fact that all chiral C2-ceramides tested failed to inhibit the activity of sphingosine kinase acting on the removal of sphingosine by producing sphingosine-l-phosphate demonstrates that chiral C2- ceramides may increase sphingosine by activating various ceramidases by which natural ceramides are divided into sphingosine and free fatty acids. However, the precise steps involved in this interaction are still unknown.

Er-Al-codoped silicate planar light waveguide-type amplifier fabricated by radio-frequency sputtering

A planar light waveguide-type optical amplifier was designed and fabricated. A core layer of Er-Al-codoped SiO>(2) glass was deposited onto a silica cladding layer by rf sputtering. In the Er-doped core layer the average Er and Al concentrations were 0.77 and 11.37 wt.%, respectively. We achieved 5 dB of gain with 20 mW of 980-nm pump power by using -20 dBm of 1546-nm input signal power.

Cytotoxic constituents from Solidago virga-aurea var. gigantea MIQ

Activity-guided fractionation of the whole plant of Solidago virga-aurea var. gigantea M(IQ). (Compositae) has led to the isolation of three cytotoxic compounds, erythrodiol-3-acetate (1), alpha-tocopherol-quinone (2), and trans-phytol (3) from the hexane soluble fraction. It is the first report of those compounds from the genus.

Improved fluorescent determination method of cellular sphingoid bases in high-performance liquid chromatography

Precolumn orthophthaldehyde (OPA) labeling method of sphingoid bases, sphingosine and sphinganine, was investigated to obtain high fluorescent detectability. In order to improve the fluorescent yield, we investigated the optimal solubility of sphingoid bases for five pre-incubation solvents by incorporating the heating procedure before OPA derivatization. The pre-incubation in ethanol prominently increased the fluorescent peak height of OPA derivative for each sphingoid bases in high performance liquid chromatography. About ten-fold increase of detectability was archived by pre-incubating lipid extracts pellets in ethanol at 60 degrees C for 30 min. Optimal derivatization was performed in 30 min at ambient temperature and the fluorescent intensity of OPA derivative was stable for two weeks at 4 degrees C. The detection limit of sphingosine was 0.1 pmol as injected amount. This method was applied to the determination of cellular sphingosine and sphinganine in various human lung cancer cells. This OPA procedure was prospective to be useful for quantitating the amount of sphingoid bases in other cancer cells.

Screening and isolation of antibiotic resistance inhibitors from herb materials IV-resistance inhibitors from Anetheum graveolens and Acorus gramineus

The hexane fractions from methanolic extracts of Anetheum graveolens L. (Umbelliferae) and Acorus gramineus Soland. (Araceae), revealed potent inhibitory activities against the resistance of multi-drug resistant Staphylococcus aureus SA2 when combined with ampicillin (Am) or chloramphenicol (Cm). As active principles, carvone and the liquid mixture containing carvone from Anetheum graveolens L. and a liquid mixture mainly consisting of benzoic acid phenylmethyl ester (benzyl benzoate) from Acorus gramineus Soland, were identified. They showed resistance inhibition at the level of 20-50 micrograms/ml when combined with 100 or 50 micrograms/ml of Am or Cm, respectively.

Application of micellar electrokinetic capillary chromatography for monitoring of hippuric and methylhippuric acid in human urine

The factors affecting micellar electrokinetic capillary chromatographic separation of hippuric and o-, m-, p-methylhippuric acid were investigated by changing the species of micelles, and adding urea to the micellar solution. The analysis of hippurates in human urine is demonstrated under optimum conditions using 20 mM phosphate buffer (pH 8.0) containing 100 mM dodecyltrimethylammonium bromide and 4 M urea at -22 kV applied voltage. This method proved suitable for the screening of hippurates in human urine following occupational exposure to toluene and xylene.

Effects of krestin (PSK) on tumorigenesis induced by two-stage and complete chemical carcinogenesis

The effects of PSK on tumorigenesis in mouse skin were investigated either when mouse skins were initiated by benzo(a)pyrene and promoted by 12-O-tetradecanoyl-phorbol-13-acetate (Group I, two-stage carcinogenesis) or when both initiated and promoted by benzo(a)pyrene (Group II, complete carcinogenesis). Twelve mice in each group were fed chow with or without 0.4% PSK. This concentration of PSK was determined by calculation to give mice enough PSK to exert antitumorigenic activity without cytotoxicity. By the end of the experimental periods (26 weeks), two carcinoma-burdened mice in Group I without PSK were dead, but no carcinomas at all were identified in the mice fed with PSK, although considerable numbers of papillomas developed in both groups. In Group II, carcinomas started to evolve at the 15th week of the experiment regardless of PSK feeding. The number of carcinomas observed in the mice fed with PSK in Group II was statistically significantly lower than that in the mice fed without PSK. Histologically, mild inflammatory infiltrations were seen around the papillomas, and moderate to dense infiltrations, mainly composed of neutrophils, T lymphocytes, and macrophages, were observed in squamous cell carcinomas. There were apparently no significant differences in the number of the infiltrating cells around carcinomas in PSK (+) and PSK (-) groups in both early and fully developed lesions. However, considerable numbers of cells infiltrating into the nests were observed in the early lesions of elicited carcinomas in the mice fed with PSK, while such cells were rarely seen in carcinoma nests in the group without PSK at that stage.(ABSTRACT TRUNCATED AT 250 WORDS)

Determination of tricyclic antidepressants in human plasma by micellar electrokinetic capillary chromatography

The factors affecting the micellar electrokinetic chromatographic separation of structurally similar tricyclic antidepressants (imipramine, amitriptyline, desipramine, nortriptyline, doxepin and trimipramine as an internal standard) were investigated by changing the species of micelles, and adding an organic modifier (urea or methanol) to the micellar solution. The determination of tricyclic antidepressants in human plasma is demonstrated under the optimum separation conditions using 37.5 mM phosphate buffer (pH 8.0) containing 25 mM dodecyltrimethylammonium bromide and 2 M urea at -25 kV applied voltage.

Analysis of antiepileptic drugs in human plasma using micellar electrokinetic capillary chromatography

We describe a method for the simultaneous determination of antiepileptic drugs (ethosuccimide, phenytoin, primidone, phenobarbital, carbamazepine and valproic acid) by micellar electrokinetic capillary chromatography using sodium dodecyl sulphate as the micellar phase. Factors affecting the micellar electrokinetic separation were studied for the quantitative determination of these drugs in human plasma. The confirmation of the peaks and the specificity of the method were investigated by combining multiwavelength detection with micellar electrokinetic capillary chromatography.

Separation of theophylline and its analogues by micellar electrokinetic chromatography: application to the determination of theophylline in human plasma

Micellar electrokinetic chromatographic separation of theophylline and its analogues was investigated using sodium dodecyl sulphate (SDS) as a micellar phase. The effects of pH, micelle concentration, applied voltage and temperature on the separation and preliminary quantitative analysis were studied for the determination of theophylline in human plasma. The data indicate that this technique could be used as the reference or routine method of theophylline measurement in therapeutic drug monitoring.

Immunohistochemical characterization of cellular infiltrates in epidermal tumors induced by two-stage and complete chemical carcinogenesis in mouse skin

We investigated the population and pattern of the infiltrated cells in both benign and malignant epidermal tumors which were induced chemically with benzo(a)pyrene (B(a)P) in murine skin. In benign papillomas, which were evolved by a two stage carcinogenesis regimen, a slight to mild inflammatory infiltration around the tumors was observed, and cells infiltrating into the tumor nests were rarely seen. In carcinomas, which were produced by a complete carcinogenesis regimen, a dense inflammatory infiltration was observed around the tumor nests. The infiltrated cells were characterized as T-lymphocytes, macrophages, and neutrophils. Natural killer (NK) cells were found around and in the tumor nests, but their number was small. Both T-lymphocytes and macrophages were found to invade the tumor nests in squamous cell carcinoma whose duration was more than four weeks. This experimental carcinogenesis animal model allows the detailed quantitative and functional analysis of the infiltration of immunocompetent cells into epidermal tumors.

A simple desalting procedure for fast atom bombardment mass spectrometry

A simple and efficient procedure for desalting samples prior to fast atom bombardment mass spectrometry utilizes low-pressure reverse-phase chromatography with disposable high-capacity mini-columns. Microscale (0.1-10 mumol) sample purification with high analyte recovery is possible for nucleosides, nucleotides and peptides. Salt removal has been evaluated both by conductivity and mass spectral methods and is greater than 99% for the model compounds cytidine, adenosine and AMP, even when they are contaminated with a 10 molar excess of NaCl. This procedure is also applicable to a range of small peptides as demonstrated with pyro-Glu-His-Gly and methionine enkephalin.