RESUMO
A disintegrin and metalloproteinase-12 (ADAM12) is involved in the regulation of myogenesis and adipogenesis and is of interest as a potential target to manipulate skeletal muscle development and intramuscular fat (IMF) deposition in cattle to increase beef yield and improve meat quality. The longissimus thoracis muscle (LM) and semitendinosus muscle (STM) from 5 Bos taurus (Angus) and 5 Bos indicus (Brahman) cattle were collected for histological and ADAM12 gene and protein expression analysis. Myofiber typing was used to determine if ADAM12 expression patterns related to differences in muscling and IMF deposition, which are influenced by proportions of the different myofiber types. The STM was found to contain a higher proportion of glycolytic myofibers than the LM, which contained a greater proportion of oxidative myofibers (myofiber ratio of glycolytic to more oxidative types in LM and STM of 1.1 and 3.5, respectively; P < 0.05). ADAM12 gene expression, fluorescent immunohistochemical staining for ADAM12, and image analysis found ADAM12 to be greater in the LM (P < 0.05). Regression analysis found a strong, positive relationship for the distribution of ADAM12 against the proportion of type I myofibers (P < 0.05, r(2) = 0.86). These findings suggest ADAM12 is upregulated in muscles with more slow-oxidative myofibres, such as the LM, and is linked to type I myofibers in cattle. ADAM12 may be important in the regulation and maintenance slow myofibers in the LM muscle.
Assuntos
Proteínas ADAM/metabolismo , Bovinos/fisiologia , Regulação Enzimológica da Expressão Gênica/fisiologia , Proteínas de Membrana/metabolismo , Fibras Musculares de Contração Lenta/enzimologia , Proteínas ADAM/genética , Proteína ADAM12 , Animais , Western Blotting , Eletroforese em Gel Bidimensional , Masculino , Proteínas de Membrana/genética , Fibras Musculares de Contração Lenta/metabolismoAssuntos
Anti-Helmínticos/farmacologia , Nematoides/efeitos dos fármacos , Infecções por Nematoides/veterinária , Doenças dos Ovinos/tratamento farmacológico , Animais , Anti-Helmínticos/uso terapêutico , Resistência a Medicamentos , Fezes/parasitologia , Haemonchus/efeitos dos fármacos , Infecções por Nematoides/tratamento farmacológico , New South Wales , Ostertagia/efeitos dos fármacos , Contagem de Ovos de Parasitas/veterinária , Ovinos , Trichostrongylus/efeitos dos fármacosRESUMO
The degradation of N6-[(dimethylamino)methylene]mitomycin C, a semisynthetic analogue of mitomycin C, was studied in aqueous solution. The compound degraded rapidly and followed pseudo-first-order kinetics in both acidic (pH less than 5) and basic pH greater than or equal to 9) media. In the near-neutral pH region, however, biphasic kinetics were observed. At the pH of maximum stability (6.5), 10% activity was lost after approximately 6 h at 22 degrees C. Citrate and phosphate species were catalytic at pH 6.5. Spectrophotometric and HPLC methods were used to elucidate the degradation mechanism at pH 7-9. Under these conditions, equilibrium addition of one water molecule into the amidine side chain occurred, followed by parallel formation of mitomycin C and N6-(formyl)mitomycin C. The latter compound subsequently hydrolyzed to mitomycin C.
Assuntos
Mitomicina , Mitomicinas/análise , Soluções Tampão , Estabilidade de Medicamentos , Concentração de Íons de Hidrogênio , Cinética , Soluções , Espectrofotometria UltravioletaRESUMO
A fast and simple procedure was developed for the quantitative determination of vincristine sulfate for use in preformulation studies. The procedure involves the use of high-performance liquid chromatography with a reverse-phase column and a mobile phase containing the sodium salt of 1-pentanesulfonic acid for ion-pairing. The procedure has been shown to be specific for vincristine sulfate in the presence of forced degradation products of this substance, vinblastine (a structurally similar Vinca alkaloid), and several possible formula excipients. The procedure is linear from 10-200% of the normal injection concentration, and has an assay precision (relative 2 sigma) of +/- 1.6%. Recovery of known samples averaged 99.7%.
