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Results for “Dansyl Compounds”

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PubMed2002

Aortic smooth muscle cell phenotypic modulation and fibrillar collagen deposition in angiotensin II-dependent hypertension.

BACKGROUND: We investigated the effect of nifedipine, AT-1 and ET-1 receptor blockade on arterial smooth muscle cell phenotypes and collagen deposition in TGRen2 transgenic rat (TGR). METHODS: Four-week-old TGR were blood pressure (BP)-matched and allocated to receive a placebo (n=8), the calcium antagonist nifedipine (n=6), the AT-1 specific receptor antagonist irbesartan (n=6), the ET(A)/ET(B) antagonist bosentan (n=6) or the ET(A)-selective antagonist BMS-182874 (n=5). Sprague-Dawley normotensive rats served as controls (n=6). After 4 weeks of treatment animals were euthanized and the left ventricle (LV) and the structural changes in intracardiac arterioles and aorta were assessed histomorphometrically. Smooth muscle cell phenotypes and fibrillar collagen content of the aortic wall were evaluated by immunostaining, using differentiation markers-specific antibodies and Syrius red staining, respectively. The changes in ET(A) and ET(B) receptor density were also assessed with quantitative autoradiography. RESULTS: Compared to placebo, only irbesartan lowered BP (P<0.001) and prevented LV and small resistance artery hypertrophy. The aorta of placebo-treated TGR showed an increase in foetal-type smooth muscle cell content and fibrillar collagen staining, compared to controls. These changes were blunted by irbesartan, which increased ET(A) receptors in the arterial wall, enhanced by BMS-182874 and unaffected by bosentan. Nifedipine also blunted both the VSMC and collagen changes despite having no effect on BP and ET(A) receptors. CONCLUSIONS: In TGRen2, vascular hypertrophy entails both smooth muscle cell phenotypic modulation and collagen deposition. These alterations do not follow closely the BP changes and seem to imply the dihydropyridine-sensitive calcium channels.

Analysis of Variance↗
PubMed1994

Effect of organic modifier on resolution of hydrophobic compounds by micellar electrokinetic chromatography.

Three organic modifiers, methanol, acetonitrile, and dimethylformamide, were used as organic modifiers to improve the resolution of hydrophobic compounds in micellar electrokinetic chromatography. The capacity factor decreased with increasing concentration of organic modifier. Acetonitrile and dimethylformamide were more effective modifiers to decrease the capacity factor than methanol. Maximum resolution was obtained when the capacity factor was reduced to about 2. Methanol enhanced the resolution for less hydrophobic compounds, while acetonitrile and dimethylformamide were better modifiers to improve the resolution for strongly hydrophobic compounds.

Acetonitriles↗
PubMed1977

Ornithine methyl ester. An unusual metabolite encountered in the urine of patients with a urea cycle disorder characterized by hyperammonemia, hyperornithinemia and homocitrullinuria.

In the urine of six subjects with a urea cycle disorder characterized by hyperammonemia, hyperornithinemia and homocitrullinuria, an unusual ninhydrin-reaction compound was encountered. This unknown on hydrolysis yielded ornithine as the only amino acid and, on dansylation studied, yielded didansyl ornithine. The metabolite from urine has been shown to have the same chromatographic mobility as ornithine methyl ester on paper cellulose thin layer, and ion exchange chromatography. When trimethylsily derivatives were prepared the unknown and the ornithine methyl ester standard had similar mobility on gas chromatography. Identification of the unknown as the ornithine methyl ester was confirmed by gas chromatography-mass spectrometric analysis. In the patients' urines the concentration of methyl ornithine ranged from 70 to 368 microne moles/g creatinine.

Amino Acid Metabolism, Inborn Errors↗
PubMed1991

Urinary excretion of CGS 5,649 and its conjugated glucuronide and sulfate in man.

Experiments in animals have indicated that CGS 5,649 B [6-(2-isopropylaminopropyl)-3-pyridinol fumarate] might enhance memory and learning processes and might be a valuable drug for treatment of impairment of vigilance and mental performance in the elderly. CGS 5,649 (I) is extensively metabolized. Therefore, we investigated the excretion of the drug and its conjugates (I-SULF,I-GLUC) into urine after oral administration of 1200 mg of the fumarate salt of I to one healthy male volunteer. Three HPLC methods were developed to analyze the three compounds in urine: a. Solid-phase extraction and UV-measurement at 280 nm; b. Dansylation followed by fluorometric detection (lambda ex 340, lambda em 525 nm); c. Direct injection of diluted urine, gradient system with ion-pair reagent and UV-detection at 280 nm. The conjugates were measured after enzymatic hydrolysis with glucuronidase/sulfatase and sulfatase. I-GLUC was also measured directly since a synthetic sample had become available. Results from the different analytical methods showed agreement: about 100% of the administered dose was excreted within 24 h; the relative amounts of I, I-SULF and I-GLUC were about 1:2:2; after oral administration, CGS 5,649 B is rapidly and completely absorbed; it is eliminated from plasma by conjugation and direct excretion into urine.

Chromatography, High Pressure Liquid↗
PubMedDate not supplied

Dansyl and dabsyl analytical constructs as tools for the accurate estimation of compounds in solid-phase synthesis.

The presence of dansyl or dabsyl chromogenic moieties in a solid-phase analytical construct, an assembly of linkers/spacers/sensitizers for improving analytical characterization, allows the accurate estimation of products from solid-phase synthesis by UV detection during liquid chromatography-mass spectrometry analysis in the cleavage solution. The spectroscopic properties of dansylated molecules have been evaluated to verify the "compound-independent UV absorption" necessary for using the chromophore in the accurate estimation. First, measurements on commercial dansylated compounds were made, then a series of construct-like molecules were prepared by solution-phase synthetic procedures and their UV properties were determined. Compound calibration curves were determined, and UV absorption was shown to be both proportional to the compound concentration and compound-independent. An example of a dansyl construct derivative was then prepared on a polymeric matrix, and an accurate estimation using the calibration curves was carried out in the cleavage solution. Good agreement was found between the calculated amount of released compound using the UV calibration curves and the calculated amount using both (1)H NMR and LC/chemiluminescent nitrogen detection quantitative techniques. Preliminary studies using the dabsyl moiety as an improved chromophore with higher wavelength and extinction coefficient are also reported.

Calibration↗
PubMed1981

Measurement of serum T4 concentration by high performance liquid chromatography.

Although RIA techniques for the measurement of serum T4 have been extremely useful, this methodology has several disadvantages, including the requirement for the use of radioisotopes, various levels of thyronine cross-reactivity, and the ability to measure only a single iodothyronine in one assay. We have developed a high performance liquid chromatography (HPLC) method for quantitating serum T4 that utilizes the detection of dansyl-T4 compounds and obviates the problems described for RIA techniques. Serum samples were extracted with ethanol and then chloroform, reacted with dansyl chloride, and, after n-heptane extraction, placed directly on column. Utilizing this technique, dansyl-T4 was easily separated and identified. The sensitivity of detection of the dansylated-T4 in serum was 1 microgram/dl, and linearity was observed when increasing standard T4 concentrations were employed. Sensitivity to 10 ng/dl (100 fmol on column) was achieved when T4 was added to buffer. The coefficients of variation were 4.8% and 2.1% for normal and high serum samples, respectively. When 39 random serum samples were anayzed both by HPLC and RIA, there was concordance of these techniques, since the derived correlation coefficient was 0.94. In summary, the present study demonstrates that serum T4 concentrations can be measured by HPLC and that these measurements agree remarkably well with those obtained by RIA. Because of the inherent advantages of HPLC methodology over that of RIA, this technique of measurement of T4 may have wide applicability to the measurement of iodothyronines.

Chromatography, High Pressure Liquid↗
PubMed1975

Denervation in the primary olfactory pathway of mice. II. Effects on carnosine and other amine compounds.

Carnosine (beta-alanyl-histidine) is present in the olfactory bulb and olfactory eqithelium of mice and rats at 1-2 nmole/mg tissue. Peripheral deafferentation or central denervation causes a rapid, selective decrease of this depeptide from the reciprocal portion of the primary olfactory pathway. These data demonstrate the localization of carnosine within the primary olfactory chemoreceptor neurons and suggest a possible role for this compound in neural transmission.

Alanine↗
PubMed2003

A novel method of imaging lysosomes in living human mammary epithelial cells.

Cancer cells invade by secreting degradative enzymes which, under normal conditions, are sequestered in lysosomal vesicles. The ability to noninvasively label lysosomes and track lysosomal trafficking would be extremely useful to understand the mechanisms by which degradative enzymes are secreted in the presence of pathophysiological environments, such as hypoxia and acidic extracellular pH, which are frequently encountered in solid tumors. In this study, a novel method of introducing a fluorescent label into lysosomes of human mammary epithelial cells (HMECs) was evaluated. Highly glycosylated lysosomal membrane proteins were labeled with a newly synthesized compound, 5-dimethylamino-naphthalene-1-sulfonic acid 5-amino-3,4,6-trihydroxy-tetrahydro-pyran-2-ylmethyl ester (6-O-dansyl-GlcNH2). The ability to optically image lysosomes using this new probe was validated by determining the colocalization of the fluorescence from the dansyl group with immunofluorescent staining of two well-established lysosomal marker proteins, LAMP-1 and LAMP-2. The location of the dansyl group in lysosomes was also verified by using an anti-dansyl antibody in Western blots of lysosomes isolated using isopycnic density gradient centrifugation. This novel method of labeling lysosomes biosynthetically was used to image lysosomes in living HMECs perfused in a microscopy-compatible cell perfusion system.

Acetylglucosamine↗
PubMed2002

A bromine compound existing in blood.

Since a bromine compound with REM-sleep-inducing and anti-choline esterase activities have been isolated from human cerebrospinal fluid, and was identified as 1-methylheptyl gamma-bromoacetoacetate, the compound was chemically synthesized. It was found that this compound was composed with three forms, i.e., a keto-form, an enol-form that changed gradually from keto-form by tautomerism, and a stable six-membered ring form (= cyclic r-Br) converted from enol form, when it was chemically synthesized. In addition, it was found that the six-membered ring form of this bromine compound was present in the human blood. However, in this case, the keto-form and the enol-form were not detected. When 14C-butyrate was injected to rats, it was incorporated into the bromine compound in the blood of the animal and the bromine compound formed was found to be present mainly as the six-membered ring form. From these results, the mechanism for the formation of bromine compounds in human and animal blood were deduced.

Acetoacetates↗