RESUMEN
Arabinoxylan (AX) and arabinoxylooligosaccharides (AXOs) are carbohydrate sources utilized by Bifidobacterium longum subsp. longum. However, their degradation pathways are poorly understood. In this study, we characterized two genes, BLLJ_1850 and BLLJ_1851, in the hemicellulose-degrading gene cluster (BLLJ_1836-BLLJ_1859) of B. longum subsp. longum JCM 1217. Both recombinant enzymes expressed in Escherichia coli exhibited exo-α-L-arabinofuranosidase activity toward p-nitrophenyl-α-L-arabinofuranoside. BlArafE (encoded by BLLJ_1850) contains the glycoside hydrolase family 43 (GH43), subfamily 22 (GH43_22), and GH43_34 domains. The BlArafE GH43_22 domain was demonstrated to release α1,3-linked Araf from AX, but the function of BlArafE GH43_34 could not be clearly identified in this study. BlArafD (encoded by BLLJ_1851) contains GH43 unclassified subfamily (GH43_UC) and GH43_26 domains. The BlArafD GH43_UC domain showed specificity for α1,2-linked Araf in α1,2- and α1,3-Araf double-substituted structures in AXOs, while BlArafD GH43_26 was shown to hydrolyze α1,5-linked Araf in the arabinan backbone. Co-incubation of BlArafD and BlArafE revealed that these two enzymes sequentially removed α1,2-Araf and α1,3-Araf from double-substituted AXOs in this order. B. longum strain lacking BLLJ_1850-BLLJ_1853 did not grow in the medium containing α1,2/3-Araf double-substituted AXOs, suggesting that BlArafE and BlArafD are important for the assimilation of AX. KEY POINTS: ⢠BlArafD GH43 unclassified subfamily domain is a novel α1,2-L-arabinofuranosidase. ⢠BlArafE GH43 subfamily 22 domain is an α1,3-L-arabinofuranosidase. ⢠BlArafD and BlArafE cooperatively degrade α1,2/3-Araf double-substituted arabinoxylan.
Asunto(s)
Glicósido Hidrolasas , Xilanos , Bifidobacterium/enzimología , Glicósido Hidrolasas/genética , Glicósido Hidrolasas/metabolismo , Especificidad por Sustrato , Xilanos/metabolismoRESUMEN
It has been shown that losartan, an angiotensin II receptor blocker (ARB), reduces serum uric acid levels. However, the effects of losartan on serum uric acid levels in the patients treated with a thiazide diuretic have not been fully elucidated. We have investigated the effects of losartan compared with other ARBs on blood variables and blood pressure control in hypertensive patients treated with a thiazide diuretic using data from the COMFORT study. The present analysis included a total of 118 hypertensive subjects on combination treatment with ARBs except for losartan and a diuretic who were randomly assigned to a daily regimen of a combination pill (losartan 50 mg/hydrochlorothiazide 12.5 mg) or to continuation of two pills, an ARB except for losartan and a diuretic. Blood pressures were evaluated at 1, 3, and 6 months after randomization and changes in blood variables including serum uric acid were evaluated during 6 months treatment period. Mean follow-up blood pressure levels were not different between the combination pill (losartan treatment) group and the control (ARBs except for losartan) group. On the other hand, serum uric acid significantly decreased in the combination pill group compared with the control group (-0.44 versus + 0.10 mg/dl; p = 0.01), although hematocrit, serum creatinine, sodium and potassium were not different between the groups. These results suggest that the treatment regimen switched from a combination therapy of ARBs except for losartan and a diuretic to a combination pill (losartan/ hydrochlorothiazide) decreases serum uric acid without affecting blood pressure control.
Asunto(s)
Presión Sanguínea/efectos de los fármacos , Hidroclorotiazida , Hipertensión , Losartán , Ácido Úrico/sangre , Anciano , Bloqueadores del Receptor Tipo 1 de Angiotensina II/administración & dosificación , Bloqueadores del Receptor Tipo 1 de Angiotensina II/farmacocinética , Diuréticos/administración & dosificación , Diuréticos/farmacocinética , Combinación de Medicamentos , Monitoreo de Drogas/métodos , Quimioterapia Combinada/métodos , Femenino , Humanos , Hidroclorotiazida/administración & dosificación , Hidroclorotiazida/farmacocinética , Hipertensión/tratamiento farmacológico , Hipertensión/metabolismo , Hipertensión/fisiopatología , Losartán/administración & dosificación , Losartán/farmacocinética , Masculino , Persona de Mediana Edad , Resultado del TratamientoRESUMEN
BACKGROUND: In order to achieve target blood pressure levels to prevent cardiovascular disease, combination therapy of antihypertensive drugs is often required, although it is thought that requiring a patient to take many different pills would reduce adherence to the medication regimen. Whether antihypertensive treatment with a single pill combining antihypertensive drugs would improve medication adherence and blood pressure control was investigated. METHODS AND RESULTS: A total of 207 hypertensive subjects were randomly assigned to a combination pill group (losartan 50mg/hydrochlorothiazide 12.5mg; n=103) or a control group (an angiotensin receptor blocker and a thiazide diuretic; n=104). Medication adherence was evaluated by pill counts at 1, 3, and 6 months after randomization. The mean adherence rates over 6 months were not different between the 2 groups: 98% in the combination pill group and 98% in the control group. Moreover, the 2 groups included similar numbers of subjects with relatively poor adherence rates (<90%) in each treatment period. The mean blood pressures over the 6-month treatment period were not different between the groups: 131/75 mmHg in the combination pill group and 130/75 mmHg in the control group (P=0.84/0.96). CONCLUSIONS: There were no appreciable effects of the combination pill of antihypertensive drugs on medication adherence or blood pressure control in Japanese patients over a 6-month period.
Asunto(s)
Bloqueadores del Receptor Tipo 1 de Angiotensina II/uso terapéutico , Antihipertensivos/uso terapéutico , Pueblo Asiatico/psicología , Presión Sanguínea/efectos de los fármacos , Diuréticos/uso terapéutico , Conocimientos, Actitudes y Práctica en Salud/etnología , Hidroclorotiazida/uso terapéutico , Hipertensión/tratamiento farmacológico , Losartán/uso terapéutico , Cumplimiento de la Medicación/etnología , Administración Oral , Anciano , Análisis de Varianza , Bloqueadores del Receptor Tipo 1 de Angiotensina II/administración & dosificación , Antihipertensivos/administración & dosificación , Distribución de Chi-Cuadrado , Diuréticos/administración & dosificación , Combinación de Medicamentos , Femenino , Humanos , Hidroclorotiazida/administración & dosificación , Hipertensión/etnología , Hipertensión/fisiopatología , Japón/epidemiología , Modelos Lineales , Losartán/administración & dosificación , Masculino , Persona de Mediana Edad , Comprimidos , Factores de Tiempo , Resultado del TratamientoRESUMEN
A 6-month, twice-a-week exercise program emphasizing swimming was conducted for 11 men (57-73 years) and 24 women (51-68 years). The control group comprised 11 male (59-70 years) and 11 female (53-70) volunteers. The exercise program significantly improved the systolic and diastolic blood pressure (SBP/DBP) and lipid and glucose metabolism, with no change in the controls. Brachial-ankle pulse wave velocity (baPWV), as an index of systemic arterial stiffness, was measured during medical examinations before and after each exercise session using a volume-plethysmographic apparatus. SBP and DBP of the extremities were significantly decreased after exercise, but did not change in the controls. Average baPWV decreased significantly in the exercise group, from 1661±50 to 1581±40 cm per sec. No change was seen in the controls. The sway path of the center of balance was analyzed using a force plate. The length of postural sway, the length of postural sway per sec and the area of postural sway were measured with eyes open and eyes closed, and the rectangular area was calculated. The eyes open/eyes closed ratio (Romberg sign) was also calculated. All parameters of body sway were significantly lower after 6 months in the exercise group, with no change in the controls. The Romberg sign did not change for either group. In addition to promoting better health, as shown by the clinical data, this type of exercise program improves balance function, which could help prevent falls of the elderly.
Asunto(s)
Presión Sanguínea/fisiología , Ejercicio Físico/fisiología , Glucosa/metabolismo , Glucosa/fisiología , Metabolismo de los Lípidos/fisiología , Equilibrio Postural/fisiología , Rigidez Vascular/fisiología , Anciano , Índice Tobillo Braquial , Pueblo Asiatico , Femenino , Humanos , Masculino , Persona de Mediana EdadRESUMEN
Interactions between endothelial cells and extracellular matrix proteins are important determinants of endothelial cell signaling. Endothelial adhesion to fibronectin through alpha(v)beta(3) integrins or the engagement and aggregation of luminal alpha(v)beta(3) receptors by vitronectin triggers Ca2+ influx. However, the underlying signaling mechanisms are unknown. The electrophysiological basis of alpha(v)beta(3) integrin-mediated changes in endothelial cell Ca2+ signaling was studied using whole cell patch clamp and microfluorimetry. The resting membrane potential of bovine pulmonary artery endothelial cells averaged -60 +/- 3 mV. In the absence of intracellular Ca2+ buffering, the application of soluble vitronectin (200 microg/ml) resulted in activation of an outwardly rectifying K+ current at holding potentials from -50 to +50 mV. Neither a significant shift in reversal potential (in voltage clamp mode) nor a change in membrane potential (in current clamp mode) occurred in response to vitronectin. Vitronectin-activated current was significantly inhibited by pretreatment with the alpha(v)beta(3) integrin antibody LM609 by exchanging extracellular K+ with Cs+ or by the application of iberiotoxin, a selective inhibitor of large-conductance, Ca2+-activated K+ channels. With intracellular Ca2+ buffered by EGTA in the recording pipette, vitronectin-activated K+ current was abolished. Fura-2 microfluorimetry revealed that vitronectin induced a significant and sustained increase in intracellular Ca2+ concentration, although vitronectin-induced Ca2+ current could not be detected. This is the first report to show that an endothelial cell ion channel is regulated by integrin activation, and this K+ current likely plays a crucial role in maintaining membrane potential and a Ca2+ driving force during engagement and activation of endothelial cell alpha(v)beta(3) integrin.
Asunto(s)
Calcio/química , Endotelio Vascular/metabolismo , Integrina alfaVbeta3/metabolismo , Potasio/química , Animales , Calcio/metabolismo , Bovinos , Adhesión Celular , Línea Celular , Células Cultivadas , Cesio/química , Ácido Egtácico/química , Electrofisiología , Fibronectinas/metabolismo , Fura-2/farmacología , Iones/química , Microscopía Fluorescente , Técnicas de Placa-Clamp , Péptidos/farmacología , Unión Proteica , Transducción de Señal , Factores de Tiempo , Vitronectina/metabolismoRESUMEN
Ion channels are regulated by protein phosphorylation and dephosphorylation of serine, threonine, and tyrosine residues. Evidence for regulation of channels by tyrosine phosphorylation comes primarily from investigations of the effects of growth factors, which act through receptor tyrosine kinases. The purpose of the present work is to summarize evidence for the regulation of ion channels by integrins, through their downstream, nonreceptor tyrosine kinases. We review both direct and indirect evidence for this regulation, with particular emphasis on Ca2+-activated K+ and voltage-gated Ca2+ channels. We then discuss the critical roles that cytoskeletal, focal-adhesion, and channel-associated scaffolding proteins may play in localizing nonreceptor tyrosine kinases to the vicinity of ion channels. We conclude by speculating on the physiological significance of these regulatory pathways.