Search results for "Spectrophotometry"
showing 10 items of 644 documents
Evidence for pleural epithelial-mesenchymal transition in murine compensatory lung growth
2017
In many mammals, including rodents and humans, removal of one lung results in the compensatory growth of the remaining lung; however, the mechanism of compensatory lung growth is unknown. Here, we investigated the changes in morphology and phenotype of pleural cells after pneumonectomy. Between days 1 and 3 after pneumonectomy, cells expressing α-smooth muscle actin (SMA), a cytoplasmic marker of myofibroblasts, were significantly increased in the pleura compared to surgical controls (p < .01). Scanning electron microscopy of the pleural surface 3 days post-pneumonectomy demonstrated regions of the pleura with morphologic features consistent with epithelial-mesenchymal transition (EMT); nam…
Measurement of Duloxetine in Blood Using High-performance Liquid Chromatography with Spectrophotometric Detection and Column Switching
2007
A method using high-performance liquid chromatography (HPLC) with column switching and ultraviolet (UV) spectroscopy was developed for the determination of duloxetine in human plasma. After centrifugation and addition of venlafaxine as internal standard, plasma samples were injected into the HPLC system and precleaned on a column (10 x 4.0 mm) filled with cyanopropyl (CN)-modified silica of 20 microm particle size, with use of 8% (vol/vol) acetonitrile in deionized water as eluent. Duloxetine was eluted and separated on a LiChrospher 100 CN (5-microm particle size; column size, 250 x 4.6 mm I.D.) using acetonitrile-water-potassium dihydrogenphosphate trihydrate buffer (pH, 6.4; 50:50 vol/vo…
Metabolism of 3-hydroxychrysene by rat liver microsomal preparations
1990
3-Hydroxychrysene, a metabolite of the polycyclic aromatic hydrocarbon (PAH) chrysene, was metabolised by rat liver microsomal preparations obtained from Arochlor 1254-pretreated rats. Eight major metabolites were isolated by high performance liquid chromatography and characterised by u.v. spectroscopy and a variety of mass spectrometric techniques. The metabolites were unambiguously identified as 9-hydroxy-trans-1,2-dihydroxy-1,2-dihydrochrysene and 9-hydroxy-r-1,t-2,t-3,c-4-tetrahydroxy-1,2,3,4-tetrahydrochrysene and tentatively identified as 3-hydroxy-trans-5,6-dihydroxy-5,6-dihydrochrysene (since chrysene is a symmetrical molecule the 3- and 9-positions are equivalent), 9-hydroxy-trans-…
Metachromatic staining and electron dense reaction of glycosaminoglycans by means of Cuprolinic Blue
1987
The cationic phthalocyanin-like dye Cuprolinic Blue, unlike phthalocyanin dyes such as Alcian Blue or Astra Blue, can definitely exhibit a clear metachromatic reaction with appropriate substrates. The application of Cuprolinic Blue to epoxy-embedded semithin sections revealed that mast cell cytoplasmic granules, goblet cell mucin and cartilage matrix stained in violet shades (metachromatic), whereas nuclear chromatin presented a bright blue coloration (orthochromatic). The metachromatic structures showed a high degree of contrast when ultrathin sections treated with Cuprolinic Blue were examined by electron microscopy. Cytophotometric measurements of stained components from the large intest…
The Effects of Sulphydryl Reagents on the Binding and Mixed Function Oxidation of Hexobarbital in Rat Hepatic Microsomes
1975
1. The effects of the sulphydryl reagents p-chloromercuribenzoate, N-ethylmaleimide and iodoacetamide on the binding spectrum, oxygen consumption and formation of a suspected substrate-cytochrome P-450-oxygen complex for hexobarbital in rat liver microsomes were investigated. 2. The oxygen consumption caused by hexobarbital oxidation was inhibited non-competitively by all three agents, with 50% inhibition at 4 times 10(-5) M for p-chloromercuribenzoate, 3-7 times 10(-4) M for N-ethylmaleimide and 1-9 times 10(-3) M for iodoacetamide. Cysteamine protected and at least partially reversed this inhibition. 3. p-chloromercuribenzoate inhibited the formation of the cytochrome P-450-substrate-oxyg…
Effect of nitrite on microsomal cytochrome P-450.
1978
1. Addition of nitrite to anaerobic rat liver microsomes leads to the appearance of a difference spectrum similar to the spectrum of the ferrous cytochrome P-450-NO complex. A Soret band is found at 444 nm in phenobarbital-stimulated microsomes but at 442 nm in 3-methylcholanthrene-stimulated microsomes. An alpha-band is located at 583 nm in both types of microsome. 2. The initial nitrite-induced difference spectrum is converted into a spectrum lacking a Soret band but with a prominent absorbance minimum at 417 nm. This is more rapid in microsomes from phenobarbital-treated animals where it is completed in 8 min than in microsomes from 3-methylcholanthrene-treated animals. A similar spectru…
Analysis of Mycobacterium tuberculosis-Specific CD8 T-Cells in Patients with Active Tuberculosis and in Individuals with Latent Infection
2009
CD8 T-cells contribute to control of Mycobacterium tuberculosis infection, but little is known about the quality of the CD8 T-cell response in subjects with latent infection and in patients with active tuberculosis disease. CD8 T-cells recognizing epitopes from 6 different proteins of Mycobacterium tuberculosis were detected by tetramer staining. Intracellular cytokines staining for specific production of IFN-gamma and IL-2 was performed, complemented by phenotyping of memory markers on antigen-specific CD8 T-cells. The ex-vivo frequencies of tetramer-specific CD8 T-cells in tuberculous patients before therapy were lower than in subjects with latent infection, but increased at four months a…
Metabolism of apigenin by rat liver phase I and phase II enzymes and by isolated perfused rat liver
2004
The metabolism of apigenin, a low estrogenic flavonoid phytochemical, was investigated in rat using liver models both in vitro (subcellular fractions) and ex vivo (isolated perfused liver). In vitro, phase I metabolism led to the formation of three monohydroxylated derivatives: luteolin which was the major metabolite (K(m) = 22.5 +/- 1.5 microM; V(max) = 5.605 +/- 0.090 nmol/min/mg protein, means +/- S.E.M.), scutellarein, and iso-scutellarein. These oxidative pathways were mediated by cytochrome P450 monooxygenases (P450s). The use of P450 inhibitors and inducers showed that CYP1A1, CYP2B, and CYP2E1 are involved. In vitro studies of phase II metabolism indicated that apigenin underwent co…
A Simple Microassay for the Determination of Hydrazine in Biological Samples. Effect of Hydrazine and Isoniazid on Liver and Brain Glutathione
1987
A simple microassay for the determination of hydrazine in laboratory samples is presented. The colored product of the reaction of p-dimethylaminobenzaldehyde with hydrazine was tested at 470 nm using double-beam mode in different samples. Internal standards and data on blood serum, liver, and brain of rats treated with hydrazine or isoniazid are presented. The tissue glutathione content of these rats was determined, and the possible implication of glutathione in the brain toxicity of hydrazine is discussed.
On the spectral intermediate at 440 nm formed during mixed function substrate oxidation.
1974
Abstract The spectral shoulder formed at 440 nm in microsomes oxidising hexobarbital and other drugs has been investigated and some of its properties characterised. Hexobarbital, pentobarbital, ethylmorphine and barbital produce this shoulder, while acetanilide, aniline, desmethylimipramine, imipramine, metyrapone and SKF 525-A do not. The formation of the 440 nm shoulder depends on the presence of NADPH and oxygen and is reduced in size when NADH is also present. At saturating substrate concentrations the size of the 440 nm shoulder is correlated to the cytochrome P-450 content. The hexobarbital induced shoulder can be inhibited by drug metabolism inhibitors such as metyrapone, imipramine …