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Biomedical subjects

A Villar

Publications and source records attributed to A Villar.

At least 145 records · Page 8Linked to original sources
PubMed1981

Cisplatin alone or in combination with adriamycin in the treatment of patients with head and neck cancer relapsed after radiotherapy and/or surgery.

37 evaluable patients with relapsed head and neck cancer received as treatment Cisplatin alone (18 patients) or Cisplatin + Adriamycin (19 patients). Both regimens consisted of three-weeks-interval courses. Cisplatin was administered at a dose of 100 mg/m2 as an i.v. infusion with prehydration, posthydration, mannitol and furosemide. Cisplatin + Adriamycin combination was administered at doses of 50 mg/m2 Cisplatin and 50 mg/m2 Adriamycin, both drugs the same day. Clinical toxicity was mild with both regimens. Overall hematologic toxicity was moderate but it was severe with regard to red cells. Some cases of renal toxicity were observed with Cisplatin regimen while no case was noticed with Cisplatin + Adriamycin combination. An overall response rate of 44% (4 CR + 4 PR) was achieved with Cisplatin protocol. The mean duration of response was 5,5 months. An overall response rate of 53% (3 CR + 7 PR) was achieved with Cisplatin + Adriamycin protocol. The mean duration of response was 2,75 months.

Basal Cell Carcinoma↗
PubMedDate not supplied

Screening methods for natural products with antimicrobial activity: a review of the literature.

Diffusion and dilution methods have been employed to study the antimicrobial activity of medicinal plants. A number of modifications have been made in the technique in order to obtain better results. Since some factors (culture medium composition, microorganisms tested, extractive method, pH, solubility of the sample in the culture medium, etc.) can change results, it is difficult using these methods to standardize a procedure for the study of antimicrobial plants. Bioautography is another method for studying antimicrobial activity. With it, previously chromatographed principles are diffused to the agar. The results can also change according to the method employed. All the various techniques are reviewed here and, in order to unify the different criteria and parameters, standard methods to study the antimicrobial activity of medicinal plants are proposed.

Anti-Infective Agents↗
PubMedDate not supplied

Isolation and identification of the antibacterial compounds from Helichrysum stoechas.

Fractionation of the dicholoromethane extract of the aerial parts of Helichrysum stoechas yielded seven isolates (1-7), which exhibited varying antimicrobial activity against Gram-positive bacteria. Pure compounds 1-3 have been previously reported in the same species and 4 and 5 were identified as italipyrone and plicatipyrone, previously isolated from H. italicum and H. plicatum. The two other isolates are helipyrone (6) and homoarenol (7) mixed with related substances. Compound 6c (4,4'-dihydroxy-5,6,5',6'-tetramethyl-3,3'-methylen-di-pyr-2-one) and 6b helipyrone with one methyl substitution, have not been previously reported in other species.

Anti-Bacterial Agents↗
PubMedDate not supplied

Antiulcerogenic activity of Lippia alba (Mill.) N. E. Brown (Verbenaceae).

Lippia alba (Mill.) N. E. Brown Verbenaceae, known popularly as 'Juanilama' or 'Salvia Sija', is prized widely in folk medicine in Guatemala. Its leaves are employed as an infusion and decoction as a remedy for stomach problems, dysentery, colds and cough, febrifuge, as well as a sedative and in spasmolitic remedies. The present study reports the effects of the infusion of L. alba on the rat gastric mucosa. The following behavioural parameters were evaluated: (a) gastric irritancy test in Wistar rats; (b) antiulcer activity, short term and long term; (c) acid secretion; (d) measurement of total proteins; (e) estimation of total protein bound and nonprotein sulfhydryl groups. Ranitidine (100 mg/kg, p.o.) was used as the reference antiulcer drug. Oral treatment with the infusion (12.5 g dry plant/kg) did not cause gastric irritancy in the rats treated during five consecutive days. In addition, the oral administration of L. alba was found to be effective at preventing gastric ulceration induced by indomethacin (50 mg/kg, p.o.) in rats in the short term (1 day) and long term (5 days).

Animals↗
PubMedDate not supplied

Anti-inflammatory compounds from Sideritis javalambrensis n-hexane extract.

The anti-inflammatory activities of the n-hexane extract of Sideritis javalambrensis and several purified fractions were investigated using the carrageenan mouse paw edema test. Progressive fractionation led to the isolation of the active principles ent-16-hydroxy-13-epimanoyl oxide [1] and esters of tyrosol with palmitic, stearic, behenic, and lignoceric acids.

Animals↗
PubMedDate not supplied

Incubated or superfused rat lung parenchymal strip: a valid preparation for direct measurement of beta-responses.

Responses to the beta-adrenoceptor agonists isoprenaline (Iso) (non selective), salbutamol (Sal) (beta 2-selective) and noradrenaline (NA) (beta 1-selective) were studied on incubated and superfused rat lung strip. In both conditions, Iso and Sal elicited dose-related relaxations of lung strip and these responses were unaffected by the presence of phentolamine (Phen) 10(-5) M. Contractile responses to NA were obtained when it was used alone whereas in the presence of Phen 10(-5) M, NA elicited relaxant responses. The relative potencies of Iso : Sal : NA (plus Phen) were 100 : 20 : 0.69. This demonstrates that beta 2-adrenoceptor is the predominant beta-subtype involved in responses. Propranolol (10(-4) M) completely abolished the relaxant responses to Iso. However, after the addition of Iso tissue responded normally to drugs acting by other mechanisms. Thus, relaxations were obtained with caffeine and contractions with acetylcholine (AcH) or NA. This shows that responses to Iso are mediated only by beta-adrenoceptors. Propranolol and the selective beta-blocking agents butoxamine (beta 2) and atenolol (beta 1) competitively antagonized the effects of Iso. The Schild plots obtained had slopes which did not differ significantly from -1 and mean pA2 values were: 7.82 for propranolol; 6.32 for butoxamine and 5.22 for atenolol. These experiments were carried out in the absence of catecholamine uptake inhibitors, since in a preliminary set of experiments no significant changes of lung strip responses to Iso were observed in the presence of cocaine (10(-5) M) or corticosterone (10(-5) M). In conclusion, it appears that incubated rat lung strip possesses intrinsic tone and, although it cannot be considered a representative preparation of peripheral airways, it provides a valid model for investigating the direct-effects of drugs which act at beta-adrenoceptors.

Albuterol↗
PubMedDate not supplied

Antihyperglycemic and insulin-releasing effects of beta-sitosterol 3-beta-D-glucoside and its aglycone, beta-sitosterol.

The effect of beta-sitosterol 3-beta-glucoside (antihyperglycemic principle isolated from the aerial part of Centaurea seridis L. var. maritima Lge.) and its aglycone on plasma insulin and glucose levels in normo- and hyperglycemic rats was investigated. The results indicate that oral treatment with the glycoside or with the beta-sitosterol increased the fasting plasma insulin levels. There was a corresponding decrease in fasting glycemia when beta-sitosterol was administered orally. In addition, these compounds improved the oral glucose tolerance test with an increase in glucose-induced insulin secretion. But when these products were administered orally, the effect of glycoside, either on fasting insulinemia or on glucose-induced insulin secretion, lasted longer than that of aglycone. The present study compared these effects with those of glibenclamide. It can be assumed that beta-sitosterol 3-beta-D-glucoside acts by increasing circulating insulin levels, and that this effect is due to their aglycone: beta-sitosterol.

Animals↗
PubMedDate not supplied

Role of intracellular calcium stores in the contractile response of uterus to several agonists.

A comparison was made of contractions produced by submaximal doses of oxytocin, noradrenaline, PGE2 and PGF2 alpha in estrogen-dominated rat uterus after the preparation had been loaded in Ca-free medium supplemented with EDTA 3 mM. The experiments were carried out in the presence of EDTA 1 mM to complex the contaminating Ca. The contraction was sustained as long as the preparation was exposed to the drug and was relaxed by washing. Cumulative concentration-response curves to oxytocin (6.25-100 microM), noradrenaline (0.05-1.6 mM), PGE2 (0.1-1.6 microM) and PGF2 alpha (0.02-0.32 microM) were made. The threshold concentration for PGF2 alpha was much lower than for PGE2, oxytocin and noradrenaline. Isoprenaline (10- -10(-4)M), KCl (56.3 mM) and caffeine (5 mM) were added. The results showed that isoprenaline and KCl did not produce contractile response. Caffeine produces only a small decrease in the resting tension and this effect is not reversible. After addition of noradrenaline, a concentration of oxytocin (6 microM) produced a uterine contraction smaller than the control response of uterus to oxytocin. The response to the oxytocin applied after washing out the caffeine was the same as the control response. All agonists tested that were capable of inducing uterine contraction in Ca-free medium act through specific receptors. This suggests a relation between receptor-operated Ca-channels and intracellular Ca-stores.

Animals↗