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1.
Diabetes Obes Metab ; 23(3): 811-821, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33416200

RESUMO

AIM: To compare the long-term efficacy of sodium-glucose co-transporter-2 inhibitors and dipeptidyl peptidase-4 inhibitors as second-line drugs after metformin for patients not at high risk of atherosclerotic cardiovascular disease (ASCVD). MATERIALS AND METHODS: In a 52-week randomized open-label trial, we compared ipragliflozin and sitagliptin in Japanese patients diagnosed with type 2 diabetes, without prior ASCVD and treated with metformin. The primary endpoint was a glycated haemoglobin (HbA1c) reduction of ≥0.5% (5.5 mmol/mol) without weight gain at 52 weeks. RESULTS: Of a total of 111 patients (mean age 59.2 years, mean body mass index [BMI] 26.6 kg/m2 , 61.3% men), 54 patients received ipragliflozin and 57 received sitagliptin. After 52 weeks, achievement of the primary endpoint was not significantly different (37.0% and 40.3%; P = 0.72). HbA1c reduction rate at 24 weeks was greater for sitagliptin (56.1%) than for ipragliflozin (31.5%; P = 0.01). From 24 to 52 weeks, the HbA1c reduction with sitagliptin was attenuated, with no significant difference in HbA1c reduction after 52 weeks between sitagliptin (54.4%) and ipragliflozin (38.9%; P = 0.10). Improvements in BMI, C-peptide and high-density lipoprotein cholesterol were greater with ipragliflozin than with sitagliptin. Adverse events occurred in 17 patients with ipragliflozin and in 10 patients with sitagliptin (P = 0.11). CONCLUSION: The HbA1c-lowering effect at 24 weeks was greater with sitagliptin than with ipragliflozin, but with no difference in efficacy related to HbA1c and body weight at 52 weeks. However, some ASCVD risk factors improved with ipragliflozin.


Assuntos
Diabetes Mellitus Tipo 2 , Inibidores da Dipeptidil Peptidase IV , Metformina , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/tratamento farmacológico , Diabetes Mellitus Tipo 2/epidemiologia , Inibidores da Dipeptidil Peptidase IV/uso terapêutico , Método Duplo-Cego , Quimioterapia Combinada , Feminino , Glucosídeos , Hemoglobinas Glicadas/análise , Humanos , Hipoglicemiantes/uso terapêutico , Masculino , Metformina/uso terapêutico , Pessoa de Meia-Idade , Fosfato de Sitagliptina/uso terapêutico , Tiofenos , Resultado do Tratamento
2.
Eur J Nutr ; 58(1): 281-290, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29222638

RESUMO

PURPOSE: Excessive meat intake has been researched as a major cause of cardiovascular disease (CVD) among healthy adults, but data on this topic in Asian patients with diabetes are sparse. The quantity and variety of available meats vary widely between Asian and Western countries. As part of a nationwide cohort study we investigated the relationship between meat intake and incidence of CVD in Japanese patients with type 2 diabetes aged 40-70 years with HbA1c ≥ 6.5%. METHODS: Analyzed were 1353 responders to a baseline dietary survey assessed by the Food Frequency Questionnaire based on food groups. Primary outcome was the 8-year risk of a CVD event, including coronary heart disease (CHD) and stroke. Cox regression analyses estimated hazard ratios (HRs) for dietary intake adjusted for age, gender, body mass index, HbA1c, smoking, energy intake, and other confounders. RESULTS: Mean meat intake in quartiles ranged from 9.9 to 97.7 g/day. After adjusting for confounders, HRs of CHD in the 2nd, 3rd, and 4th quartiles for meat intake compared with the 1st quartile were 2.84 (95% confidence interval 1.29-6.24, p = 0.01), 3.02 (1.36-6.70, p < 0.01), and 2.99 (1.35-6.65, p = 0.01), respectively. In two groups according to meat intake, patients consuming ≥ 20 g/day of meat had a 2.94-fold higher risk of CHD than those consuming < 20 g/day (p < 0.01). There was no significant association of stroke with meat intake. CONCLUSIONS: An elevated incidence of CHD in Japanese patients with type 2 diabetes was associated with high meat intake.


Assuntos
Doenças Cardiovasculares/epidemiologia , Diabetes Mellitus Tipo 2/epidemiologia , Carne/estatística & dados numéricos , Adulto , Idoso , Estudos de Coortes , Comorbidade , Dieta , Feminino , Humanos , Incidência , Japão/epidemiologia , Masculino , Pessoa de Meia-Idade , Fatores de Risco
3.
Pediatr Diabetes ; 19(4): 593-602, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29266622

RESUMO

OBJECTIVE: To examine the independent and combined associations of cardiorespiratory fitness (CRF) and muscular fitness (MF) with cardiometabolic risk factors in Japanese adolescents. METHODS: A cross-sectional study including 993 Japanese adolescents (aged 13-14 years) was undertaken. Height, body mass, blood pressure, lipid profile (non-fasting), and HbA1c were measured. The physical fitness (PF) test included measurements of CRF (20 m multistage shuttle run test), upper limb strength (hand grip strength), lower limb strength (standing long jump), and muscular endurance (sit-ups). The clustered cardiometabolic risk (CCMR) was estimated by summing standardized Z-scores of body mass index (BMI), mean arterial pressure (MAP), non-high-density lipoprotein cholesterol (non-HDL-C), and HbA1c. RESULTS: Linear regression analysis showed that all PF factors except for muscular endurance were inversely correlated with CCMR (P < .001). Among metabolic risk components, HbA1c was unrelated to PF, while non-HDL-C was inversely associated with CRF (B = -2.40; P < .001), upper limb strength (B = -1.77; P < .05), and lower limb strength (B = -1.53; P < .05) after adjustment for lifestyle factors. Logistic regression showed that the probability of having high CCMR (≥1SD) was synergistically higher in those with the lowest tertiles of both CRF and upper limb strength (P for interaction = .001); however, a substantially lower likelihood of having high CCMR was observed among individuals with the lowest tertile of upper limb strength but moderate CRF. CONCLUSIONS: Lower CRF and MF were significantly and synergistically associated with an unhealthier metabolic risk profile.


Assuntos
Aptidão Cardiorrespiratória/fisiologia , Doenças Cardiovasculares/epidemiologia , Doenças Metabólicas/epidemiologia , Força Muscular/fisiologia , Aptidão Física/fisiologia , Adolescente , Doenças Cardiovasculares/etiologia , Estudos Transversais , Teste de Esforço , Feminino , Humanos , Japão/epidemiologia , Masculino , Programas de Rastreamento , Doenças Metabólicas/etiologia , Doenças não Transmissíveis/epidemiologia , Doenças não Transmissíveis/prevenção & controle , Fatores de Risco
4.
Inorg Chem ; 57(3): 1504-1516, 2018 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-29369627

RESUMO

Novel intercluster compounds consisting of pentakis[(triphenylphosphane)gold]ammonium(2+) cation (1) and Keggin polyoxometalate (POM) anions, i.e., {[Au(PPh3)]5(µ5-N)}3[α-PM12O40]2 (1-PW for M = W; 1-PMo for M = Mo), were synthesized in 30-36% yield by one-pot reaction of the protonic acid form of the Keggin POMs, H3[α-PM12O40]·nH2O (n = 13 for M = W; n = 15 for M = Mo) with monomeric (triphenylphosphane)gold(I) carboxylate [Au(RS-pyrrld)(PPh3)] [RS-Hpyrrld = (RS)-2-pyrrolidone-5-carboxylic acid] in the presence of aqueous NH3 at a molar ratio of 2:15:x (x = 3 for 1-PW; x = 7.5 for 1-PMo). These compounds resulted from the nitrogen-centered phosphanegold(I) clusterization of in situ generated monomeric phosphanegold(I) units, [Au(PPh3)]+ or [Au(L)(PPh3)]+ (L = NH3 or solvent), during the carboxylate elimination of [Au(RS-pyrrld)(PPh3)] in the presence of the Keggin POMs and aqueous NH3. The products 1-PW and 1-PMo were characterized by elemental analysis, Fourier transform infrared, thermogravimetric and differential thermal analyses (TGA/DTA), X-ray crystallography, and solid-state cross-polarization magic-angle-spinning (CPMAS) (31P and 15N) and solution (31P{1H} and 1H) NMR spectroscopy. The lattice contained three independent {[Au(PPh3)]5(µ5-N)}2+ cations, of which two took regular trigonal-bipyramidal (TBP) geometries and the third took a distorted, square-pyramidal (SP) geometry. These geometries are in contrast to those reported by Schmidbaur's group for {[Au(PPh3)]5(µ5-N)}2+ cations as BF4 salts. Density functional theory and ONIOM calculations for {[(L3P)Au]nN}(n-3)+ (L = H or Ph; n = 4-6) showed that the pentacoordinate cluster is energetically most stable and its TBP structure is only 1.6 kcal mol-1 more stable than its SP structure, in accordance with the experimental facts.

5.
Prev Med ; 91: 180-187, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27473666

RESUMO

OBJECTIVE: Nonblood-based risk assessment for type 2 diabetes mellitus (T2DM) that depends on data based on a questionnaire and anthropometry is expected to avoid unnecessary diagnostic testing and overdiagnosis due to blood testing. This meta-analysis aims to assess the predictive ability of nonblood-based risk assessment for future incident T2DM. METHODS: Electronic literature search was conducted using EMBASE and MEDLINE (from January 1, 1997 to October 1, 2014). Included studies had to use at least 3 predictors for T2DM risk assessment and allow reproduction of 2×2 contingency table data (i.e., true positive, true negative, false positive, false negative) to be pooled with a bivariate random-effects model and hierarchical summary receiver-operating characteristic model. Considering the importance of excluding individuals with a low likelihood of T2DM from diagnostic blood testing, we especially focused on specificity and LR-. RESULTS: Eighteen eligible studies consisting of 184,011 participants and 7038 cases were identified. The pooled estimates (95% confidence interval) were as follows: sensitivity=0.73 (0.66-0.79), specificity=0.66 (0.59-0.73), LR+=2.13 (1.81-2.50), and LR-=0.41 (0.34-0.50). CONCLUSIONS: Nonblood-based assessment of risk of T2DM could produce acceptable results although the feasibility of such a screener needs to be determined in future studies.


Assuntos
Diabetes Mellitus Tipo 2/diagnóstico , Sensibilidade e Especificidade , Humanos , Programas de Rastreamento/métodos , Medição de Risco/métodos , Inquéritos e Questionários
7.
J Muscle Res Cell Motil ; 36(3): 275-86, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25697123

RESUMO

The aim of this study was to examine whether prolonged low-frequency force depression (PLFFD) that occurs in situ is the result of decreased myofibrillar Ca(2+) sensitivity and/or reduced sarcoplasmic reticulum (SR) Ca(2+) release. Intact rat gastrocnemius muscles were electrically stimulated via the sciatic nerve until force was reduced to ~50% of the initial and dissected 30 min following the cessation of stimulation. Skinned fibre and whole muscle analyses were performed in the superficial region composed exclusively of type IIB fibres. Fatiguing stimulation significantly reduced the ratio of force at low frequency to that at high frequency to 65% in skinned fibres (1 vs. 50 Hz) and 73% in whole muscles (20 vs. 100 Hz). In order to evaluate changes in myofibrillar Ca(2+) sensitivity and ryanodine receptor caffeine sensitivity, skinned fibres were activated in Ca(2+)- and caffeine-containing solutions, respectively. Skinned fibres from fatigued muscles displayed decreased caffeine sensitivity together with increased myofibrillar Ca(2+) sensitivity. Treatment with 2,2'-dithiodipyridine and reduced glutathione induced a smaller increase in myofibrillar Ca(2+)sensitivity in fatigued than in rested fibres. In fatigued muscles, S-glutathionylation of troponin I was increased and submaximal SR Ca(2+) release, induced by 4-chloro-m-cresol, was decreased. These findings suggest that in the early stage of PLFFD that occurs in fast-twitch muscles of exercising animals and humans, S-glutathionylation of troponin I may attenuate PLFFD by increasing myofibrillar Ca(2+) sensitivity and that under such a circumstance, PLFFD may be ascribable to failure of SR Ca(2+) release.


Assuntos
Músculo Esquelético/metabolismo , Músculo Esquelético/fisiologia , Miofibrilas/fisiologia , Canal de Liberação de Cálcio do Receptor de Rianodina/metabolismo , 2,2'-Dipiridil/análogos & derivados , 2,2'-Dipiridil/farmacologia , Animais , Cafeína/farmacologia , Cálcio/metabolismo , Cresóis/farmacologia , Dissulfetos/farmacologia , Glutationa/metabolismo , Masculino , Contração Muscular/efeitos dos fármacos , Contração Muscular/fisiologia , Fadiga Muscular/efeitos dos fármacos , Fadiga Muscular/fisiologia , Fibras Musculares de Contração Rápida/metabolismo , Fibras Musculares de Contração Rápida/fisiologia , Fibras Musculares de Contração Lenta/metabolismo , Fibras Musculares de Contração Lenta/fisiologia , Músculo Esquelético/efeitos dos fármacos , Miofibrilas/efeitos dos fármacos , Miofibrilas/metabolismo , Ratos , Ratos Wistar , Retículo Sarcoplasmático/efeitos dos fármacos , Retículo Sarcoplasmático/metabolismo , Retículo Sarcoplasmático/fisiologia , Troponina I/metabolismo
8.
Inorg Chem ; 54(23): 11105-13, 2015 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-26565933

RESUMO

A novel trititanium(IV)-substituted Wells-Dawson polyoxometalate (POM)-based organometallic complex, i.e., a dimeric POM containing two bridging Cp*Rh(2+) groups (Cp* = C5Me5) or [{α-P2W15Ti3O60(OH)2}2(Cp*Rh)2](16-) (D-1) with Ci symmetry, was synthesized in an analytically pure form by a 1:2 -molar ratio reaction of the organometallic precursor [Cp*RhCl2]2 with the separately prepared, monomeric trititanium(IV)-substituted Wells-Dawson POM, "[P2W15Ti3O59(OH)3](9-)" (M-1). The crystalline sample (NaK-D-1) of the water-soluble, mixed sodium/potassium salt of D-1 was obtained in the 14.7% yield, which has been characterized by complete elemental analysis, TG/DTA, FTIR, single-crystal X-ray structure analysis, and solution ((183)W, (31)P, (1)H and (13)C{(1)H}) NMR spectroscopy. Single-crystal X-ray structure analysis revealed that the two species of the protonated Wells-Dawson subunits, "[P2W15Ti3O60(OH)2](10-)" were bridged by the two Cp*Rh(2+) groups, resulting in the an overall Ci symmetry. The Cp*Rh(2+) groups were linked to the two terminal oxygen atoms of the titanium(IV) sites and one edge-sharing oxygen atom of the surface Ti-O-Ti bond. The (183)W NMR of D-1 dissolved in D2O showed that its solution structure was represented as a dimeric POM with a formula of [{α-P2W15Ti3O60(OH)3}2{Cp*Rh(OH)}2](16-) (D-2) with Ci (or S2) symmetry. A trititanium(IV)-substituted Wells-Dawson POM-supported organometallic complex has never been reported so far, and thus D-1 in the solid state and D-2 in solution are the first example of this type of complex.

9.
J Muscle Res Cell Motil ; 35(2): 179-89, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24557809

RESUMO

The present study investigated changes in autolysis of three calpain isoforms in skeletal muscles undergoing eccentric contractions (ECC), leading to prolonged force deficits. Rat extensor digitorum longus and tibialis anterior muscles were exposed to 200-repeated ECC in situ, excised immediately after or 3 or 6 days after cessation of ECC, and used for measures of force output and for biochemical analyses. Full restoration of tetanic force in ECC-treated muscles was not attained until 6 days of recovery. Maximal calpain activity determined by a fluorogenic substrate was unaltered immediately after ECC, but increased to 313 and 450 % after 3 and 6 days, respectively. Increases in the amount of autolyzed calpain-3 were apparent immediately and developed progressively with recovery time, whereas elevations of autolyzed µ- and m-calpain occurred after 3 and 6 days, respectively. The protein content was augmented only in m-calpain. It is suggested that the three calpain isoforms may be involved in the dismantling, repair, remodeling and/or regeneration processes in ECC-treated muscles.


Assuntos
Calpaína/metabolismo , Contração Muscular/fisiologia , Fibras Musculares de Contração Rápida/fisiologia , Animais , Autólise , Masculino , Fibras Musculares de Contração Rápida/metabolismo , Isoformas de Proteínas , Ratos , Ratos Wistar
10.
Ecotoxicol Environ Saf ; 96: 75-9, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23886801

RESUMO

In this study, we measured the accumulation of tributyltin (TBT) in wharf roach (Ligia exotica Roux) and examined the species' ability to be used for TBT biomonitoring in coastal environments. In an exposure test, wharf roach were exposed to TBT via diet for 2d. TBT was accumulated in wharf roach, and its metabolite dibutyltin was detected. The concentrations of these compounds gradually decreased during the depuration period, but they were still detected 12d after exposure ceased (TBT 290±140ng/g; dibutyltin 1280±430ng/g). The biological half-life of TBT in wharf roach was estimated to be about 4d. In a field study conducted in 2011-2012, wharf roach were collected from 15 coastal sites in Japan and 3 sites in Manado, Indonesia. TBT was detected in both Japanese and Indonesian samples. The highest concentration of TBT was found in wharf roach collected at Bitung ferry port, Manado (57.9±16.5ng/g), which is close to a shipyard, and the highest concentration at a Japanese site was 12.3±6.2ng/g. Thus, we were able to detect organotins in the coastal environments by testing wharf roach, suggesting that L. exotica might serve as a good bioindicator for monitoring organotin pollution.


Assuntos
Monitoramento Ambiental/normas , Isópodes/efeitos dos fármacos , Isópodes/metabolismo , Compostos Orgânicos de Estanho/análise , Compostos Orgânicos de Estanho/metabolismo , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/metabolismo , Animais , Meia-Vida , Indonésia , Japão , Fatores de Tempo
11.
Acta Diabetol ; 60(12): 1643-1650, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37439857

RESUMO

AIMS: The aim of this cohort study was to evaluate the association between urinary levels of C-megalin, a full-length form of megalin, and kidney dysfunction progression and its dependence on the urinary albumin-creatinine ratio (UACR) in individuals with diabetes. METHODS: We enrolled 1,547 individuals with diabetes who visited the ambulatory clinic at Tenri Hospital, a regional tertiary-care hospital in Tenri City, Nara Prefecture, Japan, with an estimated glomerular filtration (eGFR) of ≥ 30 mL/min/1.73 m2. The hazard ratio (HR) and 95% confidence interval (CI) were estimated using Cox proportional hazard models to examine the association between urinary C-megalin levels and eGFR decline by ≥ 40% from baseline. RESULTS: Urinary C-megalin level was not associated with ≥ 40% eGFR decline in an age-, sex-, eGFR-, systolic blood pressure-, hemoglobin-, and UACR-adjusted model in the 1,547 patients enrolled in the study. However, urinary C-megalin levels were associated with a ≥ 40% decline in eGFR when accounting for the relationship between urinary C-megalin levels and UACR in the model. This association was UACR-dependent. CONCLUSIONS: High urinary C-megalin levels were associated with progressive kidney dysfunction in individuals with diabetes, and this association was attenuated by high UACRs.


Assuntos
Diabetes Mellitus Tipo 2 , Proteína-2 Relacionada a Receptor de Lipoproteína de Baixa Densidade , Humanos , Estudos de Coortes , Diabetes Mellitus Tipo 2/complicações , Rim , Sistema de Registros , Taxa de Filtração Glomerular , Albuminúria/etiologia , Albuminúria/complicações
12.
Diabetes Res Clin Pract ; 186: 109810, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35247529

RESUMO

AIMS: Megalin is a multiligand receptor expressed in proximal tubular cells that reabsorbs filtered albumin and correlates cross-sectionally with albuminuria. We investigated the association between urinary C-megalin levels and the incidence of microalbuminuria in patients with diabetes mellitus. METHODS: This cohort study included 752 patients with type 1 or 2 diabetes mellitus and a urinary albumin-to-creatinine (Cr) ratio (UACR) within the normoalbuminuric range (<30 mg/g Cr). The association between urinary C-megalin and persistent microalbuminuria, accounting for the possible interaction between baseline UACR and urinary C-megalin, was estimated using a Cox proportional hazards model. RESULTS: During a median follow-up period of 1.99 years, 179 cases of persistent microalbuminuria were observed. The association between urinary C-megalin and persistent microalbuminuria was UACR-dependent (P for interaction < 0.001), with the highest association observed in the absence of UACR (per 100 fM/gCr of urinary C-megalin: adjusted hazard ratio, 1.13; 95% CI 1.07-1.19), gradually decreasing as UACR increased to 30 mg/g Cr. UACR dependence was confirmed by sensitivity analyses according to low-normal (<10 mg/gCr) or high-normal (10-<30 mg/gCr) UACR. CONCLUSIONS: Urinary C-megalin is associated with progression to microalbuminuria, especially in those with low-normal UACR levels, and its usefulness to identify high risk patients requires further investigation.


Assuntos
Albuminúria , Diabetes Mellitus Tipo 2 , Albuminas , Albuminúria/urina , Biomarcadores , Estudos de Coortes , Creatinina/urina , Diabetes Mellitus Tipo 2/epidemiologia , Feminino , Humanos , Proteína-2 Relacionada a Receptor de Lipoproteína de Baixa Densidade , Masculino , Sistema de Registros
13.
Inorg Chem ; 50(14): 6575-83, 2011 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-21675740

RESUMO

Preparation and structural characterization of a novel polyoxometalate (POM), [(P(2)W(15)Ti(3)O(60.5))(4)(NH(4))](35-) 1, i.e., an encapsulated NH(4)(+) cation species in the central cavity of a tetramer (called the Dawson tetramer) constituted by trititanium(IV)-substituted α-Dawson POM substructure, are described. POM 1 was synthesized by several different methods and unequivocally characterized by complete elemental analysis, thermogravimetric and differential thermal analysis (TG/DTA), FTIR spectroscopy, solution ((15)N{(1)H}, (31)P, (183)W) NMR spectroscopy, and X-ray crystallography. First, POM 1 was synthesized by a reaction of NH(4)Cl in aqueous solution with a precursor, which was derived by thermal treatment of a monomeric triperoxotitanium(IV)-substituted Dawson POM, [α-1,2,3-P(2)W(15)(TiO(2))(3)O(56)(OH)(3)](9-) 2, for 3 h in an electric furnace at 200 °C. The encapsulated NH(4)(+) cation in 1 was confirmed by (15)N{(1)H} NMR measurement and X-ray crystallography. As another synthesis of 1, a direct exchange of the Cl(-) anion encapsulated in [{α-1,2,3-P(2)W(15)Ti(3)O(57.5)(OH)(3)}(4)Cl](25-) 3 with the NH(4)(+) cation was attained by neutralizing an aqueous solution containing 3 with the addition of aqueous NH(3) (the initial pH of ca. 2-2.5 was changed to 6.4), followed by adding NH(4)Cl. It has been clarified that the conditions as to whether the anion or the cation is encapsulated in the central cavity of the Dawson tetramer were significantly related to the protonation/deprotonation of the bridging oxygen atoms on the intramolecular surface, Ti-O-Ti/Ti-OH-Ti sites constituting the Dawson subunits.


Assuntos
Compostos Organometálicos/química , Oxigênio/química , Titânio/química , Compostos de Tungstênio/química , Ânions/química , Cápsulas/química , Cátions/química , Cristalografia por Raios X , Modelos Moleculares , Estrutura Molecular , Compostos Organometálicos/síntese química , Prótons , Propriedades de Superfície
14.
J Am Chem Soc ; 132(34): 11943-51, 2010 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-20701282

RESUMO

The charge-transfer compound [{Ru(2)(O(2)CPh-o-Cl)(4)}(2)TCNQ(MeO)(2)] x CH(2)Cl(2) (1; o-ClPhCO(2)(-) = o-chlorobenzoate; TCNQ(MeO)(2) = 2,5-dimethoxy-7,7,8,8-tetracyanoquinodimethane) was synthesized from the reaction of the neutral precursors [Ru(2)(II,II)(O(2)CPh-o-Cl)(4)] (abbreviated as [Ru(2)(II,II)] or [Ru(2)(4+)]) and TCNQ(MeO)(2) in a CH(2)Cl(2)/nitrobenzene solution. The structure consists of two-dimensional layers consisting of an infinite array in which [Ru(2)(II,II)] units are involved in charge transfer to TCNQ(MeO)(2) to give a formal charge of [{Ru(2)(4.5+)}-TCNQ(MeO)(2)(*-)-{Ru(2)(4.5+)}]. Interstitial CH(2)Cl(2) molecules are located in the void spaces between the layers. Strong intralayer magnetic coupling between the units [Ru(2)(II,II)] with S = 1 or [Ru(2)(II,III)] with S = 3/2 and TCNQ(MeO)(2)(*-) with S = 1/2, as well as long-range ordering due to antiferromagnetic interlayer interactions, was observed. An antiferromagnetic ground state exists below T(N) = 75 K, which undergoes a metamagnetic transition under applied fields less than 2 T to a field-induced canted antiferromagnetic state with large coercivities up to H(c) = 1.6 T at 1.8 K. Compound 1 gradually loses the interstitial CH(2)Cl(2) molecule at room temperature to form a dried sample (1-dry) without loss of crystallinity and converts nearly reversibly back to 1 after being exposed to CH(2)Cl(2) vapor for 72 h (distinguished as 1'). Interestingly, during this process there is no significant change in lattice dimensions and bond distances or angles with a volume change of only 1.2 vol %. The only discernible difference is ordering/disordering of a pendant ligand orientation, but the magnetism is dramatically altered to a ferromagnetic state with T(c) approximately 56 K for 1-dry. The magnetic property changes are gradual and depend on the degree of interstitial CH(2)Cl(2) molecule loss with reversibility in the process of going between 1 and 1-dry. In addition, in the case of partially desolvated crystals that have mixed domains of ferromagnetically and antiferromagnetically ordered domains for desolvated and solvated segments, respectively, the complete change to ferromagnet can also be triggered by magnetic fields even if the desolvated segments are comparatively minor compared to the solvated segments in a crystal. Surprisingly, the information of the existence of ferromagnetically ordered domains is dynamically recorded in the entire crystal after applying significant magnetic fields as if the majority of the antiferromagnetically ordered domains for solvated segments were never present.


Assuntos
Complexos de Coordenação/química , Magnetismo , Cristalografia por Raios X , Transporte de Elétrons , Modelos Moleculares , Soluções
15.
J Am Chem Soc ; 132(5): 1532-44, 2010 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-20078121

RESUMO

The isostructural series of two-dimensional (2-D) fishnet-type network compounds, [{Ru(2)(O(2)CCF(3))(4)}(2)(TCNQR(x))] x n(solv) (R(x) = H(4), 1; Br(2), 2; Cl(2), 3; F(2), 4; F(4), 5), has been synthesized from the reactions of a paddlewheel diruthenium(II, II) complex, [Ru(2)(II,II)(O(2)CCF(3))(4)], and neutral TCNQ derivatives (TCNQR(x) = 2,3,5,6- or 2,5-halogen-substituted 7,7,8,8-tetracyanoquinodimethane) under anaerobic conditions. Corresponding Rh compounds 1-Rh-5-Rh, which are diamagnetic and redox-inactive, were also synthesized for the purpose of comparison with 1-5. According to the electron affinity of TCNQR(x), which is related to its first reduction potential, the Ru(2) series (1-5) has the requisite driving force for charge transfer from [Ru(2)(II,II)(O(2)CCF(3))(4)] to TCNQR(x), which can lead to a mixed-valence state of [{Ru(2)(4.5+)}-(TCNQR(x)(*-))-{Ru(2)(4.5+)}] for the 2-D network. Such a charge (or electron) transfer results in magnetic exchange interactions between [Ru(2)] units (S = 1 for [Ru(2)(II,II)] and S = 3/2 for [Ru(2)(II,III)](+)) via TCNQR(x)(*-) S = 1/2 radicals that lead to long-range magnetic ordering in the layer. In the present series, only 5 demonstrated the full electron transfer (1-e(-) transfer) to the mixed-valence state, whereas other members are essentially in the state [{Ru(2)(4+)}-(TCNQR(x)(0))-{Ru(2)(4+)}]. Whereas 1-4 are paramagnetic, 5 is a metamagnet undergoing 3-D long-range antiferromagnetic ordering at 95 K (= T(N)) and reverts to a magnetic-field-induced ferromagnetic state exhibiting coercivity up to 60 K. This result is consistent with the fact that TCNQF(4) has the strongest electron affinity among the TCNQR(x) molecules. Even in neutral forms, however, 1-4 can be observed to undergo thermally and/or field-activated charge transfers from [Ru(2)(II,II)] to TCNQR(x) to give semiconductors with an activation energy of 200-300 meV, which is a driving force to transport electrons over the lattice. As determined by their conducting properties, the ease of thermally and/or field-activated charge transfers is on the order of 1 < 4 < 2 approximately = 3 << 5, which is in agreement with the order of electron affinity of TCNQR(x). Indeed, a magnetic anomaly with short-range order associated with the localization of charge-transferred electrons was revealed in the low-temperature susceptibility data for 2 and 3. Finally, 5 was subjected to terahertz time-domain spectroscopy, the data from which revealed that transport hopping electrons scattered at high temperatures interact with magnetically ordered spins with the scattering being suppressed at T(N), at which temperature the real part of the complex electronic conductivity (sigma(1)) and dielectric permeability (epsilon(1)) are dramatically altered. From these collective data, we conclude that molecular design based on an interunit charge transfer in a paramagnetic lattice is an efficient route to the design of materials with synergism between magnetic and conducting properties.

16.
Eur J Appl Physiol ; 110(5): 943-52, 2010 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-20652583

RESUMO

The present study investigated the effects of eccentric muscle contractions (ECC) on the content of myofibrillar proteins (my-proteins) and the catalytic activity of myofibrillar ATPase (my-ATPase) in skeletal muscles. Rat extensor digitorum longus and tibialis anterior muscles were exposed to 200-repeated ECC or isometric contractions (ISC) and used for measures of force output and for biochemical analyses, respectively. Whereas in ISC-treated muscles, full restoration of tetanic force was attained after 2 days of recovery, force developed by ECC-treated muscles remained depressed (P < 0.05) after 6 days. The total my-protein content and the relative content of myosin heavy chain (MHC) in total my-proteins were unaltered during 4 days of recovery after ECC, but fell (P < 0.05) to 55.9 and 63.4% after 6 days of recovery, respectively. my-ATPase activity expressed on a my-protein weight basis was unaltered immediately after ECC. However, it decreased (P < 0.05) to 75.3, 45.3, and 49.3% after 2, 4 and 6 days of recovery, respectively. Total maximal calpain activity measured at 5 mM Ca(2+) was significantly augmented (P < 0.05) after 2 days of recovery, reaching a level of threefold higher after 6 days. These alterations were specific for ECC and not observed for ISC. These results suggest that depressions in my-ATPase activity contribute to ECC-induced decreases in force and power which can take a number of days to recover.


Assuntos
Contração Muscular/fisiologia , Proteínas Musculares/fisiologia , Músculo Esquelético/fisiologia , Miofibrilas/fisiologia , Adenosina Trifosfatases/metabolismo , Adenosina Trifosfatases/fisiologia , Animais , Calpaína/análise , Calpaína/metabolismo , Calpaína/fisiologia , Extremidade Inferior/fisiologia , Masculino , Força Muscular/fisiologia , Cadeias Pesadas de Miosina/análise , Cadeias Pesadas de Miosina/fisiologia , Ratos , Ratos Wistar
17.
Mar Pollut Bull ; 160: 111601, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32871435

RESUMO

Tributyltin-binding proteins (TBT-bps), members of the lipocalin family, bind TBT in fish blood and are presumed to contribute to detoxification of TBT. Recent studies have shown that many fish species have TBT-bp genes, and that these genes are induced by stresses such as exposure to chemicals or fish pathogenic bacteria. However, the function of TBT-bps, and the mechanisms of their induction and detoxification activity are still unclear. Here, towards elucidating the functions of TBT-bp2, we produced a TBT-bp2 knockout (TBT-bp2-/-) strain of Japanese medaka, Oryzias latipes, by using the CRISPR/Cas9 system. Gene expression of the mutated TBT-bp2 was reduced, and the cDNA sequencing and predicted protein structure suggested possible loss of function. However, the fish could be grown under normal conditions. Exposure of the TBT-bp2-/- strain of medaka to various stresses in future experiments is expected to contribute to our understanding of this novel detoxification system in aquatic organisms.


Assuntos
Oryzias , Compostos de Trialquitina , Animais , Proteínas de Transporte , Oryzias/genética , Compostos de Trialquitina/toxicidade
18.
Oecologia ; 159(3): 559-69, 2009 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19153768

RESUMO

The impact of invasive alien species on native species is of increasing global concern. Invasive plants have various negative effects on natives through competition; however, relatively little is known about competition for pollination. The relationship between Japanese native dandelions (Taraxacum spp.) and invasive congeners may be a typical case of such an interaction. For example, native dandelions are being replaced by invasive congeners, especially in urban and suburban areas of Japan. To explain this phenomenon, we hypothesized that when natives are mixed with attractive invasives, natives may suffer from reduced seed set because invasives deprive natives of pollinators or because pollinators frequently move between species, resulting in interspecific pollen transfer. To test this hypothesis, we studied the effect of the invasive dandelion T. officinale on the pollination and seed set of the native T. japonicum using artificial arrays of monospecific and mixed-species plots as well as natural populations. Taraxacum officinale attracted more pollinator visits, perhaps because it produced more nectar than T. japonicum. The number of pollinator visits to T. japonicum was reduced when the congeners were grown together, and pollinators moved frequently between the two species. The proportion of seed set for T. japonicum was reduced in the presence of T. officinale in both artificial arrays and natural populations. These results support our hypothesis that interspecific competition for pollination plays an important role in the recent replacement of native dandelions by invasive congeners in Japan. Because invasive dandelions are apomicts, negative effects are incurred only by sexual natives. Thus, this system can be recognized as a rare case of interspecific interaction through pollination.


Assuntos
Polinização , Taraxacum/fisiologia , Reprodução , Taraxacum/crescimento & desenvolvimento
19.
J Appl Physiol (1985) ; 102(5): 1850-5, 2007 May.
Artigo em Inglês | MEDLINE | ID: mdl-17303704

RESUMO

The purpose of the present study was to test the hypothesis that administration of thyroid hormone [3,5,3'-triiodo-L-thyronine (T(3))] could result in oxidation of myofibrillar proteins and, in turn, induce alterations in respiratory muscle function. Daily injection of T(3) for 21 days depressed isometric forces of diaphragm fiber bundles across a range of stimulus frequencies (1, 10, 20, 40, 75, and 100 Hz) (P < 0.05). These reductions in force production were accompanied by a remarkable increment (104%; P < 0.05) in carbonyl groups of myofibrillar proteins. In contrast, T(3) treatment has no effects on the carbonyl content in myosin heavy chain. In additional experiments, we have also tested the efficacy of carvedilol, a nonselective beta(1)- beta(2)-blocker that possesses antioxidative properties. Treatment with carvedilol dramatically improved isometric tetanic force production at stimulus frequencies from 40 to 100 Hz (P < 0.05). Carvedilol also prevented T(3)-induced contractile protein oxidation (P < 0.05). These data suggest that the oxidative modification of myofibrillar proteins may account, at least in part, for an impairment of diaphragm in hyperthyroidism.


Assuntos
Diafragma/fisiopatologia , Hipertireoidismo/fisiopatologia , Contração Isométrica , Proteínas Musculares/metabolismo , Miofibrilas/metabolismo , Estresse Oxidativo , Carbonilação Proteica , Animais , Antioxidantes/farmacologia , Carbazóis/farmacologia , Carvedilol , Diafragma/efeitos dos fármacos , Diafragma/metabolismo , Modelos Animais de Doenças , Estimulação Elétrica , Hipertireoidismo/induzido quimicamente , Hipertireoidismo/metabolismo , Contração Isométrica/efeitos dos fármacos , Masculino , Cadeias Pesadas de Miosina/metabolismo , Oxirredução , Estresse Oxidativo/efeitos dos fármacos , Propanolaminas/farmacologia , Carbonilação Proteica/efeitos dos fármacos , Ratos , Ratos Wistar , Espécies Reativas de Oxigênio/metabolismo , Tri-Iodotironina
20.
J Appl Physiol (1985) ; 122(2): 396-405, 2017 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-27979982

RESUMO

The aim of this study was to examine the in vivo effects of eccentric contraction (ECC) on calpain-dependent proteolysis of Ca2+-regulatory proteins and force production in fast-twitch skeletal muscles. Rat extensor digitorum longus muscles were exposed to 200 repeated ECC in situ and excised immediately [recovery 0 (REC0)] or 3 days [recovery 3 (REC3)] after cessation of ECC. Calpain inhibitor (CI)-treated rats were intraperitoneally injected with MDL-28170 before ECC and during REC3. Tetanic force was markedly reduced at REC0 and remained reduced at REC3. CI treatment ameliorated the ECC-induced force decline but only at REC3. No evidence was found for proteolysis of dihydropyridine receptor (DHPR), junctophilin (JP)1, JP2, ryanodine receptor (RyR), sarcoplasmic reticulum Ca2+-ATPase (SERCA)1a, or junctional face protein-45 at REC0. At REC3, ECC resulted in decreases in DHPR, JP1, JP2, RyR, and SERCA1a. CI treatment prevented the decreases in DHPR, JP1, and JP2, whereas it had little effect on RyR and SERCA1a. These findings suggest that DHPR, JP1, and JP2, but not RyR and SERCA1a, undergo calpain-dependent proteolysis in in vivo muscles subjected to ECC and that impaired function of DHPR and/or JP might cause prolonged force deficits with ECC.NEW & NOTEWORTHY Calpain-dependent proteolysis is one of the contributing factors to muscle damage that occurs with eccentric contraction (ECC). It is unclear, however, whether calpains account for proteolysis of Ca2+-regulatory proteins in in vivo muscles subjected to ECC. Here, we provide evidence that dihydropyridine receptor and junctophilin, but not ryanodine receptor and sarcoplasmic reticulum Ca2+-ATPase, undergo calpain-dependent proteolysis.


Assuntos
Cálcio/metabolismo , Calpaína/metabolismo , Depressão/metabolismo , Contração Muscular/fisiologia , Fibras Musculares de Contração Rápida/metabolismo , Proteínas Musculares/metabolismo , Animais , Canais de Cálcio Tipo L/metabolismo , Masculino , Proteínas de Membrana/metabolismo , Proteólise , Ratos , Ratos Wistar , Canal de Liberação de Cálcio do Receptor de Rianodina/metabolismo , Retículo Sarcoplasmático/metabolismo , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático/metabolismo
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