RESUMO
Real-time ultrasound is currently used for in vivo carcass evaluation of beef cattle. We estimated heritability and repeatability coefficients for ultrasound-measured carcass traits in Nelore cattle. We measured longissimus muscle area, backfat thickness, and rump fat thickness in male and female animals ranging in age from 10 to 26 months. The variance components were estimated by single-trait analysis using the derivative-free restricted maximum likelihood method, under an animal model. The complete data file included 3077 records of 1172 animals born between 2003 and 2008. Two analyses were performed using a repeatability model: a) all records of longissimus muscle area, backfat thickness, and rump fat thickness of animals aged 10 to 26 months, and b) considering two age periods (11 to 17 and 18 to 24 months). The heritability estimates ranged from 0.33 to 0.46 for longissimus muscle area, from 0.20 to 0.26 for backfat, and from 0.26 to 0.29 for rump fat, demonstrating that direct selection for these traits can provide genetic gain. The repeatability estimates were moderate, ranging from 0.42 to 0.73. The highest repeatability estimates were obtained for longissimus muscle area in both the first (0.70) and second (0.73) analyses. The repeatability estimates suggest that ultrasound measures are precise; higher precision was obtained for longissimus muscle area than for subcutaneous fat thickness. The latter could be obtained during periods of greater feed availability to increase precision.
Assuntos
Composição Corporal/genética , Bovinos/anatomia & histologia , Músculo Esquelético/anatomia & histologia , Característica Quantitativa Herdável , Gordura Subcutânea/anatomia & histologia , Fatores Etários , Animais , Peso Corporal , Brasil , Cruzamento , Bovinos/genética , Feminino , Estudos de Associação Genética , Genótipo , Masculino , Modelos Genéticos , Músculo Esquelético/diagnóstico por imagem , Fenótipo , Reprodutibilidade dos Testes , Gordura Subcutânea/diagnóstico por imagem , UltrassonografiaRESUMO
OBJECTIVE: This study describes the in vitro action of the hydroalcoholic extract and the 1,7-dihydroxy-2,3-dimethoxy xanthone isolated from P. cyparissias on agonist and ovalbumin induced contractions in trachea, from normal and actively sensitised guinea pigs. RESULTS: The hydroalcoholic extract of P. cyparissias (0.125 to 1 mg/ml), incubated with the guinea-pig trachea for 20 min, had no effect on the resting tone of the preparations, but caused a concentration-dependent, reversible and non competitive inhibition of contractions induced by acetylcholine, histamine, compound 48/80, bradykinin, substance P, prostaglandin E2 and the stable analogue of thromboxane A2 mimetic U 46619. The calculated mean IC50 values for the hydroalcoholic extract were: 0.37, 0.51, 0.06, 0.32, 0.48, 0.3 and 0.17 mg/ml, respectively. Also, the extract of P. cyparissias (0.125 to 0.5 mg/ml) antagonised, in a graded manner (IC50 of 0.46 mg/ml) ovalbumin-induced contractions in guinea-pig trachea obtained from animals which had been actively sensitised to this antigen. Pre-incubation of the preparations with the purifed xanthone isolated from P. cyparssias (2.5 to 80 microg/ml; 10.0 to 310.0 microM) caused significant and concentration-dependent, reversible and noncompetitive inhibition of the contractile responses elicited by acetylcholine, histamine, bradykinin, substance P, U 46619 and prostaglandin E2. The calculated mean IC50 values for these effects were: 132.0, 73.0, 9.2, 32.0, 110.6 and 66.0 microM, respectively. At very high concentrations (I55.0-620.0 microM) the xanthone also antagonised contraction induced by KCl in guinea-pig trachea (IC50 of 190.0 microM). CONCLUSIONS: Taken together these and our previous in vivo results are consistent with the view that the active principles present in P. cyparissias, including the 1,7-dihydroxy-2,3-dimethoxy xanthone, antagonise, in a non competitive but, reversible manner the contractions induced by chemical inflammatory mediators in the guinea pig trachea in vitro. Thus, these results might explain at least in part, the medicinal use of this plant in the management of inflammation, asthma and allergy.
Assuntos
Mediadores da Inflamação/farmacologia , Contração Muscular/efeitos dos fármacos , Ovalbumina/farmacologia , Rosales/química , Traqueia/efeitos dos fármacos , Xantenos/farmacologia , Xantonas , Animais , Relação Dose-Resposta a Droga , Interações Medicamentosas , Feminino , Cobaias , Técnicas In Vitro , Masculino , Extratos Vegetais/farmacologia , Fatores de Tempo , Traqueia/fisiologia , Xantenos/isolamento & purificaçãoRESUMO
This study describes the fungistatic effect of xanthoxyline (CAS 90-24-4) and its derivatives against a panel of yeasts, filamentous fungi and dermatophytes, by using the agar dilution method. Results indicated that simple structural modifications led to more potent derivatives, especially in relation with dermatophytes. The most active compound tested (10), which is a benzenesulphonyl derivative, was 12-fold more potent than xanthoxyline itself against Trichophyton rubrum. The evaluation of the mode of action with the whole cell Neurospora crassa assay, suggested that some selected compounds may be acting by the inhibition of fungal cell-wall polymers synthesis or assembly.
Assuntos
Acetofenonas/síntese química , Antifúngicos/síntese química , Fungos/efeitos dos fármacos , Acetofenonas/farmacologia , Antifúngicos/farmacologia , Arthrodermataceae/efeitos dos fármacos , Fenômenos Químicos , Físico-Química , Cetoconazol/farmacologia , Testes de Sensibilidade Microbiana , Neurospora crassa/efeitos dos fármacos , Neurospora crassa/ultraestrutura , Trichophyton/efeitos dos fármacos , Leveduras/efeitos dos fármacosRESUMO
The barks of Drimys winteri are used in folk medicine as a remedy to treat several diseases, including dolorous processes. Previous pre-clinical experiments carried out in our laboratories revealed that the hydroalcoholic extract of this plant showed anti-allergenic, anti-inflammatory and antinociceptive properties. Such promising results led us to determine the analgesic compounds present in D. winteri. Through conventional chromatographic procedures with fractions of CH2Cl2 and EtOAc obtained from methanolic extract, it was found that polygodial (1), 1-beta-(p-methoxycynnamyl) polygodial (2), taxifolin (3) and astilbin (4), are the main components of these fractions. Compounds 1 and 2 exhibited marked antinociceptive action by intraperitoneal and oral routes against acetic acid-induced abdominal constrictions in mice, suggesting that they are responsible, at least partially, for the antinociceptive effects of this plant. In addition, both compounds were notably more potent than aspirin and acetaminophen, two well-known drugs used here as comparison.
Assuntos
Analgésicos/farmacologia , Flavonoides/farmacologia , Extratos Vegetais/farmacologia , Plantas Medicinais/química , Terpenos/farmacologia , Acetaminofen/farmacologia , Ácido Acético/toxicidade , Animais , Aspirina/farmacologia , Cromatografia em Gel , Masculino , Medicina Tradicional , CamundongosRESUMO
This study describes the action of the sesquiterpene polygodial, the major constituent isolated from the bark of Drymis winteri in the guinea pig ileum and trachea in vitro. Polygodial (5 to 128 microM), added for 20 min, did not affect the resting tone of the preparations, but caused graded inhibition, associated in some cases with rightward displacement of the acetylcholine, histamine (1 nM to 10 microM), bradykinin (0.1 nM to 1 microM) and KCl (1 to 100 mM)-contraction response curves. When assessed in the guinea-pig trachea, polygodial (5 to 342 microM) caused significant inhibition of bradykinin (10 pM to 1 microM), 9,11-dideoxy-9alpha,11alpha-methano-epoxy prostaglandin F2alpha (0.1 to 1000 nM) and KCl (1 to 100 mM)-induced contractions, although the action against bradykinin was not concentration-dependent. Polygodial (5 to 80 microM) caused a small but significant shift to the right of substance P and also the selective agonist of tachykinin NK2 receptor [beta-Ala8]neurokinin A-(4-10)-induced contractions in guinea pig trachea. This action of polygodial seems to be quite selective towards tachykinin NK2 receptors since up to 432 microM, polygodial had no effect against contraction caused by tachykinin NK1 receptor agonist, substance P methyl ester. When tested in the guinea-pig trachea from animals which had been actively sensitised to ovalbumin, polygodial (30 to 40 microM) caused time and concentration-dependent inhibition of ovalbumin-mediated contraction. In addition, polygodial (85 to 342 microM) inhibited contraction induced by compound 48/80 (1 to 1000 microg/ml), in the guinea-pig trachea from non-sensitised animals. These findings and those from our previous study are consistent with the notion that the main sesquiterpene polygodial isolated from the bark of D. winteri is responsible for most, if not all, of the relevant pharmacological action reported previously for the extract of this plant. Thus, polygodial could be of potential value in the development of a new drug for the treatment of asthma, allergy and other inflammatory processes.
Assuntos
Íleo/efeitos dos fármacos , Músculo Liso/efeitos dos fármacos , Plantas Medicinais , Sesquiterpenos/farmacologia , Traqueia/efeitos dos fármacos , Animais , Feminino , Cobaias , Histamina/metabolismo , Hipersensibilidade/metabolismo , Íleo/fisiologia , Técnicas In Vitro , Masculino , Relaxamento Muscular , Músculo Liso/fisiologia , Ovalbumina , Traqueia/fisiologiaRESUMO
As part of our research programme to obtain pharmacologically active compounds structurally related to cyclic imides, we have synthesized different compounds and examined their analgesic activities using the abdominal constriction test in mice. The results showed that some of the compounds studied, given intraperitoneally, exhibited graded and significant analgesia against acetic acid-induced abdominal constriction, being several times more potent than aspirin and paracetamol, two standard drugs used for comparison.
Assuntos
Analgésicos/farmacologia , Imidas/farmacologia , Animais , Masculino , Camundongos , Relação Estrutura-AtividadeRESUMO
Polygala cyparissias (Polygalaceae) grows abundantly on Brazil's Atlantic coast, belonging to the typical underbrush vegetation of dunes and have been used in folk medicine for treatment of several diseases, such as disturbances of bowel and kidney. The hydroalcoholic extract of P. cyparissias (HE, 3 to 60 mg kg(-1), i.p. or 25 to 200 mg kg(-1), p.o.) produced significant and graded inhibition of acetic acid-induced abdominal constrictions, with mean ID50 values of 6 and 72 mg kg(-1), respectively. The HE (at this same range of doses) also produced dose-related inhibition of both the early and the late phase of formalin-induced licking. The calculated mean ID50 values for the early phase were: >60 and >200 mg kg(-1), while for the late phase they were 11 and 101 mg kg(-1), respectively, by i.p. and p.o. routes. The HE also caused dose-related inhibition of formalin-induced edema formation (P<0.01). The HE (3 to 60 mg kg(-1), i.p. or 50 to 200 mg kg(-1), p.o.) produced significant and dose-related inhibition of the neurogenic nociception caused by topical injection of capsaicin, with mean ID50 values of 12 and 71 mg kg(-1), respectively. Given orally, the HE (50 to 200 mg kg(-1)) prevented in a dose-dependent manner, bradykinin (3 nmol/paw) and substance P (10 nmol/paw)-induced hyperalgesia in the rat paw, with mean ED50 values of 122 and 121 mg kg(-1), respectively, but was ineffective in the hot-plate model of nociception. The antinociception caused by the HE, in contrast to that of morphine (5 mg kg(-1), s.c.), was not reversed by naloxone (5 mg kg(-1), i.p.) when assessed in the acetic acid writhing test. The HE, at antinociceptive doses, did not affect motor coordination of animals when assessed in the rota-rod model. The xanthone isolated from P. cyparissias, identified as 1,7-dihydroxy-2,3-dimethoxy xanthone (0.3 to 30 mg kg(-1), i.p.), produced dose-related inhibition of acetic acid-induced abdominal constriction, with mean ID50 value of 1.5 mg kg(-1). These data show that the active principle(s) present in the HE of P. cyparissias, elicited pronounced antinociception when assessed by i.p. or p.o. routes, against both inflammatory and neurogenic nociception, and was able to prevent bradykinin and substance P-induced hyperalgesia. Its precise mechanism of action still remains unclear.