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Biomedical subjects

Z Riedl

Publications and source records attributed to Z Riedl.

6 recordsLinked to original sources
PubMed2004

Direct evidence for activation and desensitization of the capsaicin receptor by N-oleoyldopamine on TRPV1-transfected cell, line in gene deleted mice and in the rat.

Effects of the endogenous lipid N-oleoyldopamine (OLDA) were analyzed on the rTRPV1-expressing HT1080 human fibrosarcoma cell line (HT5-1), on cultured rat trigeminal neurons, on the noxious heat threshold of rats and on nocifensive behavior of TRPV1 knockout mice. The EC(50) of capsaicin and OLDA on (45)Ca accumulation of rTRPV1-expressing HT5-1 cells was 36 nM and 1.8 microM, respectively. The efficacy of OLDA was 60% as compared to the maximum response of capsaicin. OLDA (330 nM to 3.3 microM) caused a transient increase in fluorescence of fura-2 loaded cultured small trigeminal neurons of the rat and rTRPV1-transfected HT5-1 cells measured with a ratiometric technique. Repeated application of OLDA and capsaicin caused similar desensitization in the Ca(2+) transients both in cultured neurons and rTRPV1-transfected HT5-1 cells. In the rat intraplantar injection of OLDA (5 nmol) decreased the noxious heat threshold by 6-9 degrees C and this response was strongly inhibited by the TRPV1 antagonist iodoresiniferatoxin (0.05 nmol intraplantarly (i.pl.)). In wild-type mice OLDA (50 nmol i.pl.) evoked paw lifting/licking which was significantly less sustained in TRPV1 knockout mice. It is concluded that on TRPV1 capsaicin receptors OLDA is 50 times less potent than capsaicin and it might serve as an endogenous ligand for TRPV1 in the rat, but more likely in humans.

Animals↗
PubMed2002

Effect of plasticizer on the dynamic surface tension and the free volume of Eudragit systems.

The purpose of the present study was to determine the changes of dynamic surface tension of aqueous Eudragit dispersions quantitatively and compare these data with the free volume of the free films formed from several dispersions of different dibutyl sebacate (DBS) concentrations. Eudragit L 30D and Eudragit RL 30D aqueous colloidal polymer dispersions and their cast free films were examined. The concentration of DBS varied in the dispersions from 0 to 20%. The dynamic surface tension of the dispersions were measured by the Du Nouy ring method while the free volume of cast films were determined by positron annihilation spectroscopy. The obtained results show that dynamic surface tension measurements indicate the white point (WP) of Eudragit dispersions by a significant standard deviation increase. This may suggest the applicability of dynamic surface tension measurements for the determination of the WP of polymeric dispersions. A decrease in the WP temperature of Eudragit dispersions with an increasing plasticizer concentration was observed up to the DBS concentration of 10% w/w. Above this concentration neither the WP of the polymer dispersion nor the free volume of the free films of the polymer were changed remarkably.

Chemistry, Pharmaceutical↗
PubMed2001

Ellipticine analogues and related compounds as inhibitors of reverse transcriptase and as inhibitors of the efflux pump.

Ten polycyclic derivatives related to ellipticine have been synthesised and tested for their intercalating, reverse transcriptase (RT) inhibitory and multidrug resistance efflux pump inhibitory properties. The intercalating activity and the RT inhibitory activity of the derivatives suggest that ellipticine analogues bind at an allosteric binding site on RT or that this inhibition could be controlled at the DNA level. The MDR efflux pump inhibitory activities of these derivatives, however, appears to be unrelated to the DNA binding ability.

Animals↗
PubMed2000

The effect of temperature and polymer concentration on dynamic surface tension and wetting ability of hydroxypropylmethylcellulose solutions.

The purpose of the present study was to evaluate quantitatively the changes of dynamic surface tension and contact angle of hydroxypropylmethylcellulose (HPMC) aqueous solutions as a function of temperature and polymer concentration of the examined solutions. HPMC aqueous solutions of different concentrations (1%, 2%, 3%, 4% w/w) were prepared without plasticizer and with 1% w/w Lutrol F127. Dynamic surface tension of the prepared solutions was determined by the Du Nouy ring method of the KSV Sigma 70 computer-controlled and programmable tensiometer. The dynamic contact angle of Avicel PH-101 tablets was measured against HPMC solutions of various concentrations by the plate method of the KSV Sigma 70 tensiometer. The obtained results indicate that dynamic surface tension measurement can be applied for the accurate determination of the thermal gelation temperature of the prepared HPMC solutions. With increasing concentration of HPMC, dynamic contact angle values of solutions also increased, thus decreasing the spreading behavior on the surface of Avicel tablets.

Anticholesteremic Agents↗
PubMed1983

A latex agglutination test for lectin binding.

Blood group A + H substance purified from hog gastric mucin was fixed to polystyrene particles by physical absorption to produce a lectin-agglutinable latex. Agglutination of this latex by soybean agglutinin, concanavalin A, and wheat germ agglutinin is specifically inhibited by the respective monosaccharide haptens and is not affected by known noninhibitory sugars. The sensitivity of the assay, a function of particle loading and latex concentration, approaches that of the hemagglutination test. NaCl, NaHCO3, NH4CO3, NH4-acetate, and Tris-HCl up to a concentration of 1 M do not interfere with the test. The latex suspension is stable for several months and can be stored in freeze-dried form.

ABO Blood-Group System↗