摘要:

AbstractA comparative study of plasmid DNA loading, release characteristics, and stability on polystyrene divinylbenzene and ceramic hydroxyapatite ion‐exchange microspheres was undertaken. The two plasmids evaluated were pCMV‐CAT and pRcCMV‐p53. The effect of quantity of plasmid, temperature and alteration of the surface charge of microspheres on binding were examined.Binding correlated with the concentration of plasmid DNA available in the suspension. pCMV‐CAT was bound twice as much in relation to copy number on both microspheres compared with pRcCMV‐p53. Each hydroxyapatite microsphere bound 350% more plasmid than polystyrene divinylbenzene. No difference in binding was evident for either plasmid at 4, 20 or 37°C. Equilibration of both microsphere types with different salt solutions altered binding capacities when compared with that with water. In‐vitro release studies revealed that 1011copies of plasmids were being eluted from the microspheres at a flow rate of 3.0 mL h−1of phosphate‐buffered saline at 37°C. Hydroxyapatite microspheres released plasmids in a sustained manner, while polystyrene divinylbenzene microspheres released DNA in a burst. There was no plasmid degradation post‐loading on to and post‐release off microspheres.The present study has demonstrated that ion‐exchange microspheres are capable of carrying plasmid DNA and at least in‐vitro, releasing

ISSN:1460-8081    

DOI:10.1111/j.2042-7158.1996.tb00642.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractPlumbagin was encapsulated in microspheres using poly(D,L‐lactide)‐co‐glycolide (PLGA) (50:50).The in‐vitro release profile was triphasic suggesting different drug release mechanisms. The release of the drug could be controlled for about four weeks. The toxicity of plumbagin was reduced in mice after subcutaneous injection when it was encapsulated in microspheres. The volume doubling time of PLGA‐loaded microspheres was significantly higher compared with the plain drug in sarcoma

ISSN:1460-8081    

DOI:10.1111/j.2042-7158.1996.tb00643.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractHigh field1H NMR spectra of the commercially‐available H1‐receptor antagonist 1‐methyl‐4‐diphenylmethox‐ypiperidine HCl (1, diphenylpyraline) showed that the protonated base, in aqueous solution, exists as an approximately 1:1 mixture of eq‐ and ax‐4‐diphenylmethoxypiperidines (1, 2). In view of the proposed importance of the intramolecular distances between the protonated nitrogen and the centres of gravity of the aromatic substituents with respect to ligand recognition at the H1‐receptor the 3‐methylpiperidine analogues (4, 6, R = CHPh2) have been chosen to explore this hypothesis and we report the successful syntheses of these two novel conformationally restricted analogue

ISSN:1460-8081    

DOI:10.1111/j.2042-7158.1996.tb00644.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractThe role of membrane fluidity on organic ion transport in rat renal basolateral membranes (BLM) was studied.The membrane fluidizing agent benzyl alcohol decreased the fluorescence anisotropy of 1,6‐diphenyl‐1,3,5‐hexatriene in BLM, representing an increase in BLM fluidity. Na+‐dependent, dicarboxylate‐stimulated organic anionp‐aminohippurate uptake by BLM vesicles was inhibited by benzyl alcohol. This decreasedp‐aminohippurate transport was probably due to the decrease in rate of Na+/dicarboxylate cotransport induced by benzyl alcohol. In contrast to the organic anion transport, uptake of the organic cation tetraethylammonium by BLM vesicles was not influenced by benzyl alcohol.These findings indicate that the organic anion transport system is more susceptible to changes in membrane fluidity than the organic cation transport system, and membrane fluidity should be an important determinant of organic anion transport

ISSN:1460-8081    

DOI:10.1111/j.2042-7158.1996.tb00645.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractIn a previous study we showed that enteric coated mucoadhesive particles administered orally delivered 5‐fluorouracil slowly to the colon. This present study extends these investigations into an in‐vitro cell line.Human colonic adenocarcinoma cells (Caco‐2) were cultured as confluent monolayers on polycarbonate filters in Transwell systems for investigating in‐vitro cytotoxic effects of different concentrations of 5‐fluorouracil over the range 0.077‐7.7 μM. Cell damage was determined by measuring changes in the transepithelial electrical resistance (TEER).The results suggested that 5‐fluorouracil at all concentrations tested significantly affected the Caco‐2 cells. Application of residuals to the experimental TEER data indicated that the relationship between square‐root of time and TEER was linear (P>0.05), indicating that the drug may affect the Caco‐2 cells by a diffusional mechanism. There was no suggestion of a minimal or threshold concentration of drug required to affect the cells o

ISSN:1460-8081    

DOI:10.1111/j.2042-7158.1996.tb00646.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractOrganic cations are actively transported in the renal brush‐border membrane (BBM) by the H+/organic cation antiport system. In the present study, we investigated the developmental changes in organic cation transport in BBM. Uptake of organic cation tetraethylammonium (TEA) by BBM vesicles from 14‐day‐old rats was actively driven by the outward H+gradient and showed apparent overshoot. However, the initial rate and magnitude of the overshoot of TEA uptake by BBM vesicles from 14‐day‐old rats were smaller than by those from adult (8‐week‐old) rats. The transport activity increased with age, and reached the adult level in 28‐day‐old rats. The dissipation rate of the H+gradient, a driving force for the organic cation transport in BBM, was not increased in 14‐day‐old rats. H+gradient‐independent TEA‐TEA exchange in BBM was also smaller in 14‐day‐old rats than in adult rats. On the other hand, the substrate specificity of organic cation transport system and the affinity of each substrate were identical in the BBM from adult and 14‐day‐old rats.The H+/organic cation antiport system, which has characteristics similar to that in adult rats but with low activity, exists in the renal BBM of 14‐day‐old rats and the transporter activity

ISSN:1460-8081    

DOI:10.1111/j.2042-7158.1996.tb00647.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractThe antimuscarinic activity of clozapine, an atypical antipsychotic was studied on rat anococcygeus muscle. Acetylcholine (1‐128 μg mL−1) induced a concentration‐dependent contraction of the smooth muscle. Clozapine (10−8‐10−6M) shifted the concentration‐response curve of acetylcholine to the right in a parallel fashion without suppressing the maximum. The pA2value was found to be 7.37 ± 0.24 and slope 0.86 ± 0.08.The data show that clozapine blocks the muscarinic receptors in a co

ISSN:1460-8081    

DOI:10.1111/j.2042-7158.1996.tb00648.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractIt has been suggested that human erythrocyte anionic glutathioneS‐transferase rho (GST‐p) may be used as a marker of chemical exposure. In the present study, the activity of GST‐pin human erythrocyte was measured after incubation of the erythrocytes with some common xenobiotics, and since it has also been suggested that human erythrocyte GST‐pand human placental GST‐π are identical, the effect of nicotine on purified human placental GST was also determined.Nicotine and cotinine caused an inhibition of the erythrocyte enzyme. There were no effects of malathion, monocrotophos or endosulfan on the erythrocyte enzyme activity. Acrolein,N‐ethylmaleimide and styrene oxide, were confirmed as inhibitors o

ISSN:1460-8081    

DOI:10.1111/j.2042-7158.1996.tb00649.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractCroton oil is known to contain a potent tumour‐promoting factor, 12‐O‐tetradecanoylphorbol 13‐acetate (TPA), which is responsible for generation of oxygen free radicals and in turn the free radicals lead to lipid peroxidation. Such lipid peroxidation is assumed to induce severe inflammatory changes, increased vascular permeability and generation of proinflammatory hydroperoxides. Commonly used antioxidants are known to inhibit TPA. Our earlier results obtained from studies withPluchea indicaindicated that the methanolic fraction of the root extract possess significant anti‐inflammatory and antioxidant activity.The present study was designed to assess the degree of inhibitory effect ofP. indicaon croton oil‐induced mouse ear oedema, lipid hydroperoxide formation, peroxidizability of the epidermal layer and also in‐vitro lipid peroxidation (using FeCl3/ADP/NADPH and

ISSN:1460-8081    

DOI:10.1111/j.2042-7158.1996.tb00650.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractUrolithiasis was induced by 1% ethylene glycol administered in drinking water in Wistar strain female albino rats. Increase in serum urea was seen on day 14 and creatinine remained at the control value throughout the study. One group of ethylene glycol‐treated rats received Nerunjil kudineer, a commercial Siddha drug containing powderedTribulus terrestris, an indigenous plant.The drug‐treated animals showed increased urinary output, decreased serum urea and crystalluria on day 14, and a tendency for alkalinization of urine compared with the ethylene glycol‐treated animals, thus providing preliminary evidence for the clinical usefulness of this

ISSN:1460-8081    

DOI:10.1111/j.2042-7158.1996.tb00651.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY