Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 16 de 16
Filtrar
1.
Biosci Biotechnol Biochem ; 86(4): 528-534, 2022 Mar 21.
Artículo en Inglés | MEDLINE | ID: mdl-35150233

RESUMEN

The fruit of Prunus mume (ume, also known as Japanese apricot) has been used as a functional food in Japan since ancient times. We previously reported that ume stimulates the differentiation of preosteoblastic cells. Osteocalcin (OCN) is secreted by osteoblasts, and there is known association with glucolipid metabolism and cognitive function. This study sought to clarify the relationship between ume extracts and OCN production both in vitro and in vivo. Alkaline phosphatase activity and OCN level in the ethyl acetate extracts of ume-treated extracts were significantly increased in preosteoblast MC3T3-E1 cells compared with the control group. In human study, serum OCN level was significantly higher in the high ume intake group than in the low intake group in community-dwelling participants over 60 years old. These results suggest that ume has the potential to upregulated OCN production both in vitro and in vivo.


Asunto(s)
Prunus armeniaca , Prunus , Frutas/metabolismo , Humanos , Persona de Mediana Edad , Osteoblastos/metabolismo , Osteocalcina/genética , Extractos Vegetales/metabolismo , Extractos Vegetales/farmacología
2.
BMC Geriatr ; 16(1): 166, 2016 Sep 27.
Artículo en Inglés | MEDLINE | ID: mdl-27677265

RESUMEN

BACKGROUND: A concept referred to as locomotive syndrome (LS) was proposed by the Japanese Orthopaedic Association in order to help identify middle-aged and older adults who may be at high risk of requiring healthcare services because of problems associated with locomotion. Cardiometabolic disorders, including obesity, hypertension, diabetes, and dyslipidemia, have a high prevalence worldwide. The purpose of this study was to determine the associations between LS and both body composition and cardiometabolic disorders. METHODS: The study participants were 165 healthy adult Japanese women volunteers living in rural areas. LS was defined as a score ≥16 on the 25-question Geriatric Locomotive Function Scale (GLFS-25). Height, body weight, body fat percentage, body mass index (BMI), and bone status were measured. Bone status was evaluated by quantitative ultrasound (i.e., the speed of sound [SOS] of the calcaneus) and was expressed as the percent of Young Adult Mean of the SOS (%YAM). Comorbid conditions of hypertension, hyperlipidemia, and diabetes were assessed using self-report questionnaires. RESULTS: Twenty-nine participants (17.6 %) were classed as having LS. The LS group was older, shorter, and had a higher body fat percentage, a higher BMI, and lower bone status than the non-LS group. Multiple logistic regression analysis showed that participants with a BMI ≥23.5 kg/m2 had a significantly higher risk for LS than those with a BMI <23.5 kg/m2 (odds ratio [OR] = 3.78, p < 0.01). Furthermore, GLFS-25 scores were higher in participants with than those without hypertension, diabetes, or obesity, and significantly increased with the number of present disorders. CONCLUSIONS: These findings suggest that BMI may be a useful screening tool for LS. Furthermore, because hypertension and diabetes were associated with LS, the prevention of these disorders accompanied by weight management may help protect against LS.

3.
Hypertens Res ; 46(8): 1923-1933, 2023 08.
Artículo en Inglés | MEDLINE | ID: mdl-37308550

RESUMEN

Fruit from the Prunus mume tree is a traditional food in Japan. Recently, bainiku-ekisu, an infused juice concentrate of Japanese Prunus mume, is attracting attention as a health promoting supplement. Angiotensin II (Ang II) plays a central role in development of hypertension. It has been reported that bainiku-ekisu treatment attenuates the growth-promoting signaling induced by Ang II in vascular smooth muscle cells. However, whether bainiku-ekisu has any effect on an animal model of hypertension remains unknown. Therefore, this study was designed to explore the potential anti-hypertensive benefit of bainiku-ekisu utilizing a mouse model of hypertension with Ang II infusion. Male C57BL/6 mice were infused with Ang II for 2 weeks and given 0.1% bainiku-ekisu containing water or normal water for 2 weeks with blood pressure evaluation. After 2 weeks, mice were euthanized, and the aortas were collected for evaluation of remodeling. Aortic medial hypertrophy was observed in control mice after Ang II infusion, which was attenuated in bainiku-ekisu group with Ang II infusion. Bainiku-ekisu further attenuated aortic induction of collagen producing cells and immune cell infiltration. Development of hypertension induced by Ang II was also prevented by bainiku-ekisu. Echocardiograph indicated protection of Ang II-induced cardiac hypertrophy by bainiku-ekisu. In vascular fibroblasts, bainiku-ekisu attenuated vascular cell adhesion molecule-1 induction, an endoplasmic reticulum stress marker, inositol requiring enzyme-1α phosphorylation, and enhancement in glucose consumption in response to Ang II. In conclusion, Bainiku-ekisu prevented Ang II-induced hypertension and inflammatory vascular remodeling. Potential cardiovascular health benefit to taking bainiku-ekisu should be further studied.


Asunto(s)
Hipertensión , Prunus domestica , Prunus , Ratones , Animales , Angiotensina II/farmacología , Remodelación Vascular/fisiología , Ratones Endogámicos C57BL , Hipertensión/inducido químicamente , Hipertensión/tratamiento farmacológico , Hipertensión/metabolismo
4.
Arch Orthop Trauma Surg ; 132(3): 399-403, 2012 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-22258178

RESUMEN

The distal clavicle fractures are divided into three types according to Neer's classification. Types 1 and 3 fractures are treated with a sling to immobilize the upper extremity. However, the treatment of type 2 fractures is controversial. We paid attention to the anatomic basis of type 2 fractures that the disruptions of the conoid ligament lead to the distraction between the two bony fragments. In this study, we describe the arthroscopic procedure to reconstruct the disrupted ligament and stabilize the fracture as a minimally invasive method. The subjects were seven patients with the distal clavicle fractures. According to Neer's or Rockwood's classification on plain radiographs, all seven patients were evaluated as type 2 or 2B, respectively. Our surgical procedure was performed with the patient in the beach chair position. We have used the artificial ligament with an EndoButton (Smith & Nephew Endoscopy, Andover, MA) as the substitute ligament to reconstruct the disrupted conoid ligament. The mean duration of postoperative follow-up was 2 years and 5 months. The bony union was achieved in all patients at a final follow-up. When concerning the range of motion at final examinations, mean forward flexion was 171°, mean abduction was 165°, mean internal rotation was Th11, and mean horizontal adduction was 132°. It is possible to treat the distal clavicle fractures by a minimally invasive arthroscopic procedure without opening the fracture site of clavicle.


Asunto(s)
Artroscopía , Clavícula/lesiones , Clavícula/cirugía , Fracturas Óseas/cirugía , Adulto , Fijación de Fractura/métodos , Humanos , Masculino , Persona de Mediana Edad , Procedimientos Ortopédicos/instrumentación , Procedimientos Ortopédicos/métodos
5.
Artículo en Inglés | MEDLINE | ID: mdl-36078393

RESUMEN

BACKGROUND: Oral dysfunction is related to long-term cares including activities of daily living. The objective of this study was to determine the association between oral function and the bone-related physiological substances osteocalcin (OC) and insulin-like growth factor-1 (IGF-1). METHODS: The study participants were 139 community-dwelling older people in Japan. Evaluation of oral dysfunction was based on subjective judgment by each participant. Blood analysis included OC, IGF-1, and albumin. RESULTS: Univariate and multiple logistic analyses showed that IGF-1 was significantly associated with a "decline in masticatory function" (p = 0.0074 and p = 0.0308, respectively). Receiver operating characteristic curve analysis of IGF-1 levels revealed a threshold score of 108 ng/mL (p < 0.01) for discriminating a "decline in masticatory function". Logistic regression analysis revealed that participants with an IGF-1 level ≤108 ng/mL had an odds ratio of 4.31 (p < 0.05) for a "decline in masticatory function". No significant association was found between the OC level and oral dysfunction. CONCLUSIONS: These results suggest a possible relationship between lower serum IGF-1 levels and a decline in masticatory dysfunction in community-dwelling older people.


Asunto(s)
Vida Independiente , Factor I del Crecimiento Similar a la Insulina , Salud Bucal , Osteocalcina , Actividades Cotidianas , Anciano , Estudios Transversales , Humanos , Factor I del Crecimiento Similar a la Insulina/química , Factor I del Crecimiento Similar a la Insulina/metabolismo , Japón , Masticación/fisiología , Osteocalcina/química , Osteocalcina/metabolismo
6.
Biosci Biotechnol Biochem ; 75(10): 1907-11, 2011.
Artículo en Inglés | MEDLINE | ID: mdl-21979066

RESUMEN

Osteoporosis is a serious disease caused by decreased bone mass. There is constant matrix remodeling in bones, by which bone formation is performed by osteoblastic cells, whereas bone resorption is accomplished by osteoclast cells. We investigated the effect of a Japanese apricot (Prunus mume SIBE. et ZUCC.) extract on the proliferation and osteoblastic differentiation in pre-osteoblastic MC3T3-E1 cells. An alkaline phosphatase (ALP) activity assay, cell proliferation assay, alizarin red staining and expression analysis of osteoblastic genes were carried out to assess the proliferation and osteoblastic differentiation. The water-soluble fraction of Prunus mume (PWF) increased the ALP activity, cell proliferation and mineralization. The gene expression of osteopontin and bone morphogenetic protein-2, which are markers in the early period of osteoblastic differentiation, were significantly enhanced by the PWF treatment. PWF therefore stimulated the proliferation and osteoblastic differentiation of cells and may have potential to prevent osteoporosis.


Asunto(s)
Osteoblastos/citología , Osteoblastos/efectos de los fármacos , Extractos Vegetales/farmacología , Prunus/química , Células 3T3 , Fosfatasa Alcalina/metabolismo , Animales , Calcificación Fisiológica/efectos de los fármacos , Diferenciación Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Regulación de la Expresión Génica/efectos de los fármacos , Ratones , Osteoblastos/metabolismo
7.
Eur J Pharmacol ; 885: 173435, 2020 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-32745602

RESUMEN

Zanthoxylum piperitum (ZP, 'Japanese pepper') is a traditional medicine and pepper used in Asian countries such as Japan. Hydroxy-α-sanshool, a pungent-tasting substance contained within ZP, has been reported to slightly suppress immunoglobulin E (IgE)-mediated mast cell degranulation. The current study aims to newly identify anti-allergic compounds derived from ZP. We examine the inhibitory mechanisms behind IgE-mediated mast cell degranulation. By inhibitory effect-guided isolation, we identified degranulation inhibitory compounds derived from ZP fruit: 1-acetoxy-7-hydroxy-3, 7-dimethylocta-2E, 5E-diene (ZP1) and 8-hydroxygeranyl acetate (ZP2). ZP1 and ZP2 inhibited IgE-mediated degranulation and A23187-mediated degranulation in RBL-2H3 mast cells. Our findings suggest the inhibition of degranulation by ZP1 and ZP2 was by inhibition of Lyn phosphorylation, followed by inhibition of intracellular Ca2+ mobilization, protein kinase C alpha phosphorylation, membrane ruffling, and granule-to-plasma membrane fusion. Oral administration of ZP1 or ZP2 attenuated an IgE-mediated passive cutaneous anaphylactic reaction in mice. Histological observation suggests that this effect occurred via inhibition of mast cell degranulation. These findings indicate that ZP1 and ZP2 attenuate allergic reaction via inhibition of IgE-mediated mast cell degranulation.


Asunto(s)
Antialérgicos/farmacología , Degranulación de la Célula/efectos de los fármacos , Frutas/química , Hipersensibilidad/tratamiento farmacológico , Inmunoglobulina E/efectos de los fármacos , Mastocitos/efectos de los fármacos , Zanthoxylum/química , Animales , Calcimicina/farmacología , Línea Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Masculino , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos ICR , Anafilaxis Cutánea Pasiva/efectos de los fármacos , Ratas
8.
Endocrinology ; 160(10): 2339-2352, 2019 10 01.
Artículo en Inglés | MEDLINE | ID: mdl-31504411

RESUMEN

Osteoporosis is a complication of diabetes mellitus (DM). The pathology of diabetic osteoporosis is distinct from postmenopausal osteoporosis, and there are no specific treatment guidelines for diabetic osteoporosis. In the current study, this issue was addressed by evaluating the effect of osteoporosis medications, such as the anabolic agent PTH [teriparatide (TPTD)] and the antiresorptive agents calcitonin [elcatonin (ECT)] and bisphosphonate [risedronate (RIS)], on bone metabolism as well as on glucose and lipid metabolism in spontaneously diabetic Torii (SDT) fatty rats, which are a model of type 2 DM (T2DM). The medicines were injected subcutaneously into 8-week-old male SDT fatty rats three times weekly for 8 weeks. TPTD treatment in SDT fatty rats increased the osteoblast number and function on trabecular bone in vertebrae, and increased the trabecular bone mass, bone mineral density (BMD), and mechanical strength of vertebrae. Additionally, TPTD improved cortical bone structure and increased BMD. RIS decreased the osteoclast number and function, which led to an increase in vertebral bone mineral content and BMD in the femoral diaphysis, and mechanical strength was increased in the vertebrae. ECT showed no clear effects on bone mass or metabolism. Similar to diabetic lesions, all of the drugs had no effects on hyperglycemia, pancreas morphology, or serum insulin and glucagon levels. However, triglyceride levels and lipid droplets in fatty liver were decreased in the TPTD group. These results suggest that TPTD may be useful for treating fatty liver in addition to osteoporosis in T2DM.


Asunto(s)
Huesos/efectos de los fármacos , Huesos/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Metabolismo de los Lípidos/efectos de los fármacos , Teriparatido/farmacología , Animales , Glucemia , Densidad Ósea/efectos de los fármacos , Regulación de la Expresión Génica/efectos de los fármacos , Glucosa/metabolismo , Hígado/metabolismo , Masculino , ARN Mensajero/metabolismo , Ratas , Ratas Endogámicas
9.
Sci Rep ; 8(1): 17001, 2018 11 19.
Artículo en Inglés | MEDLINE | ID: mdl-30451912

RESUMEN

Calcitonin (CT) plays an important role in calcium homeostasis, and its precursor, proCT, is positively associated with the body mass index in the general human population. However, the physiological role of endogenous CT in the regulation of metabolism remains unclear. Knockout mice with gene-targeted deletion of exon 4 of Calca (CT KO) were generated by targeted modification in embryonic stem cells. Male mice were used in all experiments and were fed a slightly higher fat diet than the standard diet. The CT KO mice did not exhibit any abnormal findings in appearance, but exhibited weight loss from 15 months old, i.e., significantly decreased liver, adipose tissue, and kidney weights, compared with wild-type control mice. Furthermore, CT KO mice exhibited significantly decreased fat contents in the liver, lipid droplets in adipose tissues, serum glucose, and lipid levels, and significantly increased insulin sensitivity and serum adiponectin levels. CT significantly promoted 3T3-L1 adipocyte differentiation and suppressed adiponectin release. These results suggested that CT gene deletion prevents obesity, hyperglycemia, and hyperlipidemia in aged male mice. This is the first definitive evidence that CT may contribute to glucose and lipid metabolism in aged male mice, possibly via decreased adiponectin secretion from adipocytes.


Asunto(s)
Péptido Relacionado con Gen de Calcitonina/fisiología , Calcitonina/metabolismo , Dieta Alta en Grasa/efectos adversos , Glucosa/metabolismo , Lípidos/análisis , Hígado/metabolismo , Obesidad/metabolismo , Adiponectina/metabolismo , Tejido Adiposo/citología , Tejido Adiposo/metabolismo , Animales , Composición Corporal , Femenino , Resistencia a la Insulina , Hígado/citología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Obesidad/etiología , Obesidad/patología
10.
Sci Rep ; 8(1): 11638, 2018 08 03.
Artículo en Inglés | MEDLINE | ID: mdl-30076416

RESUMEN

Japanese apricot (Prunus mume; ume) is a traditional food in Japan that has been shown to have various beneficial health effects. There is some evidence to suggest that ume is also effective against allergic disease. Here, we conducted a cross-sectional epidemiological pilot study to examine the association between ume intake frequency and allergic symptoms including rhinitis in 563 adults (288 men and 275 women) who resided in Wakayama, Japan. After adjusting for age, present illness and medication, women with high ume intake had significantly lower odds ratio (OR) for the presence of symptoms of allergy [OR: 0.49 with 95% confidence interval (CI): 0.25-0.97]. Therefore, we investigated the anti-allergic effect of ume on passive cutaneous anaphylaxis (PCA) reaction in immunoglobulin E (IgE)-sensitized mice. The animal study demonstrated that oral administration of ume extract attenuated the PCA reaction and mast cell degranulation. Furthermore, RBL-2H3 mast cells were used to identify anti-allergic ume compounds. The following ume compounds inhibited IgE-mediated mast cell degranulation: vanillin, syringic acid, protocatechuic aldehyde, lyoniresinol and p-coumaric acid. These results suggested that ume has the potential to inhibit mast cell degranulation and may be associated with reduced risk of allergic symptoms in women.


Asunto(s)
Antialérgicos/administración & dosificación , Anafilaxis Cutánea Pasiva/efectos de los fármacos , Prunus/química , Rinitis Alérgica/dietoterapia , Adulto , Anciano , Animales , Antialérgicos/química , Femenino , Alimentos , Humanos , Inmunoglobulina E/administración & dosificación , Inmunoglobulina E/inmunología , Japón/epidemiología , Masculino , Mastocitos/efectos de los fármacos , Ratones , Persona de Mediana Edad , Extractos Vegetales/administración & dosificación , Extractos Vegetales/química , Rinitis Alérgica/epidemiología , Rinitis Alérgica/inmunología , Rinitis Alérgica/patología
11.
Curr Gerontol Geriatr Res ; 2017: 4104802, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28479917

RESUMEN

Locomotive syndrome (LS) is a concept that refers to the condition of people requiring healthcare services because of problems associated with locomotion. Depression is a major psychiatric disease among the elderly, in addition to dementia. The purpose of this study was to determine the association between LS and depression. The study participants were 224 healthy elderly volunteers living in a rural area in Japan. LS was defined as scores ≥ 16 on the 25-question Geriatric Locomotive Function Scale (GLFS-25). Depression was defined as scores ≥ 5 on the 15-item Geriatric Depression Scale (GDS-15). Height and body weight were measured. The prevalence of LS and depression was 13.9% and 24.2%, respectively. Compared with the non-LS group, the LS group was older, was shorter, had a higher BMI, and had higher GDS-15 scores. Logistic regression analysis showed that participants with GDS-15 scores ≥ 6 had higher odds for LS than those with GDS-15 scores < 6 (odds ratio [OR] = 4.22). Conversely, the depression group had higher GLFS-25 scores than the nondepression group. Participants with GLFS-25 scores ≥ 5 had higher odds for depression than those with GLFS-25 scores < 5 (OR = 4.53). These findings suggest that there is a close relationship between LS and depression.

12.
Acta Histochem Cytochem ; 47(3): 103-12, 2014 Jun 28.
Artículo en Inglés | MEDLINE | ID: mdl-25320407

RESUMEN

Granulosa cells form ovarian follicles and play important roles in the growth and maturation of oocytes. The protection of granulosa cells from cellular injury caused by oxidative stress is an effective therapy for female infertility. We here investigated an effective bioactive compound derived from Prunus mume seed extract that protects granulosa cells from hydrogen peroxide (H2O2)-induced apoptosis. We detected the bioactive compound, 3,4-dihydroxybenzaldehyde (3,4-DHBA), via bioactivity-guided isolation and found that it inhibited the H2O2-induced apoptosis of granulosa cells. We also showed that 3,4-DHBA promoted estradiol secretion in granulosa cells and enhanced the mRNA expression levels of steroidogenic factor 1, a promoter of key steroidogenic enzymes. These results suggest that P. mume seed extract may have clinical potential for the prevention and treatment of female infertility.

13.
Food Chem ; 139(1-4): 371-6, 2013 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-23561119

RESUMEN

Angiotensin II (Ang II) is a vasoactive hormone that has been implicated in cardiovascular diseases. Here, the effect of peach, Prunus persica L. Batsch, pulp extract on Ang II-induced intracellular Ca(2+) mobilization, reactive oxygen species (ROS) production and signal transduction events in cultured vascular smooth muscle cells (VSMCs) was investigated. Pretreatment of peach ethyl acetate extract inhibited Ang II-induced intracellular Ca(2+) elevation in VSMCs. Furthermore, Ang II-induced ROS generation, essential for signal transduction events, was diminished by the peach ethyl acetate extract. The peach ethyl acetate extract also attenuated the Ang II-induced phosphorylation of epidermal growth factor receptor and myosin phosphatase target subunit 1, both of which are associated with atherosclerosis and hypertension. These results suggest that peach ethyl acetate extract may have clinical potential for preventing cardiovascular diseases by interfering with Ang II-induced intracellular Ca(2+) elevation, the generation of ROS, and then blocking signal transduction events.


Asunto(s)
Angiotensina II/metabolismo , Regulación hacia Abajo/efectos de los fármacos , Músculo Liso Vascular/citología , Miocitos del Músculo Liso/efectos de los fármacos , Miocitos del Músculo Liso/metabolismo , Extractos Vegetales/farmacología , Prunus/química , Transducción de Señal/efectos de los fármacos , Animales , Células Cultivadas , Receptores ErbB/metabolismo , Músculo Liso Vascular/efectos de los fármacos , Músculo Liso Vascular/metabolismo , Fosforilación , Ratas , Especies Reactivas de Oxígeno/metabolismo
14.
Am J Hypertens ; 24(5): 530-3, 2011 May.
Artículo en Inglés | MEDLINE | ID: mdl-21331052

RESUMEN

BACKGROUND: Health benefits of brown rice over white rice have been described previously. However, whether the outer bran of rice contains an ingredient useful to prevent cardiovascular diseases remains unknown. The subaleurone layer of rice, which is usually lost by milling brown rice for whitening, is rich in varied nutrients, suggesting that some ingredient contained within this layer may be beneficial for the cardiovascular system. METHODS: To assess potential benefits of the subaleurone layer toward pathological vascular remodeling, we examined the effects of the layer extracts from Japanese rice (Oryza sativa var. japonica) on angiotensin II (Ang II)-induced signal transduction and hypertrophy in cultured rat vascular smooth muscle cells (VSMCs). RESULTS: Pretreatment of the ethyl acetate extract (100 µg/ml), but not other extracts, inhibited Ang II (100 nmol/l)-induced immediate signal transduction events. Also, the extract diminished c-Fos expression and hypertrophic protein accumulation induced by Ang II in the cells. CONCLUSION: These data suggest that an ingredient in the ethyl acetate extract from the subaleurone layer of rice has a protective effect toward cardiovascular diseases by interfering with signal transduction induced by Ang II.


Asunto(s)
Angiotensina II/antagonistas & inhibidores , Músculo Liso Vascular/efectos de los fármacos , Miocitos del Músculo Liso/efectos de los fármacos , Oryza , Extractos Vegetales/farmacología , Transducción de Señal/efectos de los fármacos , Animales , Calcio/metabolismo , Células Cultivadas , Receptores ErbB/metabolismo , Hipertrofia , Músculo Liso Vascular/metabolismo , Músculo Liso Vascular/patología , Miocitos del Músculo Liso/fisiología , Fosforilación , Proteínas Proto-Oncogénicas c-fos/análisis , Ratas , Ratas Sprague-Dawley
15.
Biophys J ; 92(1): 323-9, 2007 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-16997869

RESUMEN

We present here the first detailed kinetic analysis of the dissociation reaction of amyloid protofibrils by utilizing pressure as an accelerator of the reaction. The experiment is carried out on an excessively diluted typical protofibril solution formed from an intrinsically denatured disulfide-deficient variant of hen lysozyme with Trp fluorescence as the reporter in the pressure range 3-400 MPa. From the analysis of the time-dependent fluorescence decay and the length distribution of the protofibrils measured on atomic force microscopy, we conclude that the protofibril grows or decays by attachment or detachment of a monomer at one end of the protofibril with a monomer dissociation rate independent of the length of the fibril. Furthermore, we find that the dissociation reaction is strongly dependent on pressure, characterized with a negative activation volume DeltaV(odouble dagger) = -50.5 +/- 1.60 ml mol(-1) at 0.1 MPa and with a negative activation compressibility Deltakappa(double dagger) = -0.013 +/- 0.001 ml mol(-1) bar(-1) or -0.9 x 10(-6) ml g(-1) bar(-1). These results indicate that the protofibril is a highly compressible high-volume state, but that it becomes less compressible and less voluminous in the transition state, most probably due to partial hydration of the existing voids. The system eventually reaches the lowest-volume state with full hydration of the monomer in the dissociated state.


Asunto(s)
Péptidos beta-Amiloides/química , Biofisica/métodos , Animales , Pollos , Disulfuros/química , Cinética , Microscopía de Fuerza Atómica , Microscopía Fluorescente , Muramidasa/química , Fragmentos de Péptidos , Presión , Desnaturalización Proteica , Termodinámica , Factores de Tiempo
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA