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1.
ACS Appl Mater Interfaces ; 14(31): 35978-35984, 2022 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-35894872

RESUMO

Redox-active organic molecules are promising candidates for next-generation electrode materials. Nevertheless, finding low-molecular-weight organic materials with a long cycle life remains a crucial challenge. Herein, we demonstrate the application of tetrathiafulvalene and its vinyl analogue bearing triphenylamines as long-cycle-life electrodes for lithium-ion batteries (LIBs). These molecules were successfully synthesized using palladium-catalyzed C-H arylation. Electrochemical analysis revealed that a polymer formed on the electrode. LIBs comprising these molecules exhibited noteworthy charge-discharge properties with a long cycle life (the capacity after 100 cycles was greater than 90% of the discharge capacity in the third cycle) and a high utilization ratio (approximately 100%). "In-cell" polymerization during the first charge process is considered to contribute to the effect. This study indicates new avenues for the creation of organic materials for rechargeable batteries.

2.
Dent Mater J ; 41(4): 534-544, 2022 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-35321972

RESUMO

It is difficult to control corrective forces in orthodontic treatment with clear aligners. The grip of aligners on teeth is important to ensure accurate corrective forces from aligners. This study aimed to measure the gripping force of aligners under various conditions to clarify factors that influence it. We created aligners with different attachment morphologies and placement sites and different margin lengths. We developed a device to measure the mechanics involved in the removal of these aligners. The gripping force was evaluated at five different aligner removal sites on the teeth. We found that the gripping force of the aligner was the weakest on the lingual side of the first molar and strongest on the labial side of the central incisors and that the attachment morphology and placement sites affected the gripping force of aligners.


Assuntos
Desenho de Aparelho Ortodôntico , Aparelhos Ortodônticos Removíveis , Humanos , Incisivo , Dente Molar , Técnicas de Movimentação Dentária
4.
Dent Mater J ; 40(6): 1437-1444, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34334506

RESUMO

Numerous experimental studies have examined how much orthodontic force is needed to move teeth more smoothly; however, no reports have examined this clinically in individual, living subjects. We aimed to develop a method for quantifying the force exerted on individual teeth by an orthodontic wire to measure how loads placed on crowded teeth change dynamically over time. Accordingly, we fabricated a series of dental casts of patients undergoing orthodontic treatment (using optical impressions and a three-dimensional printer), fitted these models with nickel-titanium wire, and subjected them to bending load tests. During leveling, nickel-titanium wire is generally considered to exert a weak force due to its low elastic modulus, with a weak orthodontic force applied over a long period of time due to its superelasticity; however, we found that the actual energy exerted by nickel-titanium wire is also largely affected by other factors (e.g., amount of crowding).


Assuntos
Ligas Dentárias , Fios Ortodônticos , Elasticidade , Humanos , Teste de Materiais , Titânio
5.
J Biomech ; 113: 110079, 2020 12 02.
Artigo em Inglês | MEDLINE | ID: mdl-33254058

RESUMO

Functional appliances are widely used for promoting mandibular growth by utilizing a construction bite position. We aimed to measure the mechanical load generated by movement of functional appliances and determine the factors influencing this load. Thirteen patients aged 8-12 years were selected for the study, and the load was measured using a previously developed measurement device. To investigate the factors affecting the load, the temporomandibular joint morphology and muscles related to the mandible were examined using cone-beam computed tomography. The standard regression coefficients of the factors affecting the load per millimeter of movement distance were 0.64 and 0.66 for (a) the inclination of the articular eminence and (b) the angle between occlusal plane and posterior temporalis, respectively. Measurement of the occlusal plane to the posterior temporalis and the inclination of the articular eminence were significantly different (p < 0.05). The angle of inclination of the articular eminence emerged as a strong influencing factor. Similarly, the influence of measurements from the occlusal plane to the posterior temporalis was considerable since the posterior temporalis muscle is the most active when the mandible is extended forward. We also found a possible relationship between the occlusal force and load at the construction bite position. To our knowledge, this is the first study to determine the actual load associated with the angle of the temporalis muscle to the occlusal plane, inclination angle of the articular eminence, angle between the occlusal plane and the Frankfort plane, and the angle between the geniohyoid muscle and the occlusal plane. Therefore, mechanical considerations need to be more accurate to facilitate safe orthodontic treatment.


Assuntos
Força de Mordida , Aparelhos Ortodônticos Funcionais , Fenômenos Biomecânicos , Criança , Tomografia Computadorizada de Feixe Cônico , Humanos , Mandíbula , Articulação Temporomandibular/diagnóstico por imagem , Suporte de Carga
6.
Beilstein J Org Chem ; 16: 974-981, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32509028

RESUMO

Novel multistage redox tetrathiafulvalenes (TTFs) bearing 6-aryl-1,4-dithiafulvene moieties were synthesized by palladium-catalyzed direct C-H arylation. In the presence of a catalytic amount of Pd(OAc)2, P(t-Bu3)·HBF4, and an excess of Cs2CO3, the C-H arylation of TTF with several aryl bromides bearing 1,3-dithiol-2-ylidenes took place efficiently to produce the corresponding π-conjugated molecules. We also succeeded in the estimation of the oxidation potentials and number of electrons involved in each oxidation step of the obtained compounds by digital simulations.

7.
J Healthc Eng ; 20172017.
Artigo em Inglês | MEDLINE | ID: mdl-29072888

RESUMO

In running cars or trains, passengers often feel sleepy. Our study focuses on this physiological phenomenon. If a machine can reproduce this phenomenon, it is feasible to put a person, such as an insomnia patient or an infant, to sleep without any harmful effects. The results of our previous study suggest that low-frequency vibration induces sleep. This report describes a new mechanical bed for inducing sleep and discusses the effects of different vibration conditions. The new bed has two active DOFs in the vertical and horizontal directions to examine the anisotropy of sensation. The bed includes three main parts: a vertical driver unit, a horizontal driver unit, and a unique 2-DOF counterweight system to reduce driving force and noise. With regard to motion accuracy, the maximum motion error in the vertical direction lifting 75 kg load was only 0.06 mm with a 5.0 mm amplitude of a 0.5 Hz sinusoidal wave. The results of excitation experiments with 10 subjects showed a significant difference in sleep latency between the conditions with vibration and without vibration. Furthermore, the average latency with insensible vibration (amplitude = 2.4 mm) was shorter than that with sensible vibration (amplitude = 7.5 mm). These results suggest the ability of appropriate vibration to induce sleep.

8.
J Healthc Eng ; 2017: 2364659, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29065579

RESUMO

In running cars or trains, passengers often feel sleepy. Our study focuses on this physiological phenomenon. If a machine can reproduce this phenomenon, it is feasible to put a person, such as an insomnia patient or an infant, to sleep without any harmful effects. The results of our previous study suggest that low-frequency vibration induces sleep. This report describes a new mechanical bed for inducing sleep and discusses the effects of different vibration conditions. The new bed has two active DOFs in the vertical and horizontal directions to examine the anisotropy of sensation. The bed includes three main parts: a vertical driver unit, a horizontal driver unit, and a unique 2-DOF counterweight system to reduce driving force and noise. With regard to motion accuracy, the maximum motion error in the vertical direction lifting 75 kg load was only 0.06 mm with a 5.0 mm amplitude of a 0.5 Hz sinusoidal wave. The results of excitation experiments with 10 subjects showed a significant difference in sleep latency between the conditions with vibration and without vibration. Furthermore, the average latency with insensible vibration (amplitude = 2.4 mm) was shorter than that with sensible vibration (amplitude = 7.5 mm). These results suggest the ability of appropriate vibration to induce sleep.


Assuntos
Leitos , Sono , Vibração , Adulto , Desenho de Equipamento , Voluntários Saudáveis , Humanos , Masculino , Fenômenos Mecânicos , Inquéritos e Questionários , Adulto Jovem
9.
J Biomech ; 63: 197-202, 2017 10 03.
Artigo em Inglês | MEDLINE | ID: mdl-28935342

RESUMO

Devices called functional appliances are commonly used in orthodontics for treating maxillary protrusion. These devices mechanically force the mandible forward to apply traction force to the mandibular condyle. This promotes cartilaginous growth in the small mandible. However, no studies have clarified how much traction force is applied to the mandibular condyle. Moreover, it remains unknown as to how anatomical characteristics affect this traction force. Therefore, in this study, we developed a device for measuring the amount of force generated while individual patients wore functional appliances, and we investigated the relationship between forces with structures surrounding the mandibular condyle. We compared traction force values with cone-beam computed tomography image data in eight subjects. The functional appliance resulted in a traction force of 339-1477gf/mm, with a mean value of 196.5gf/mm for the elastic modulus of the mandible. A comparison with cone-beam computed tomography image data suggested that the mandibular traction force was affected by the mandibular condyle and shape of the articular eminence. This method can contribute to discovering efficient treatment techniques more suited to individual patients.


Assuntos
Má Oclusão Classe II de Angle/diagnóstico por imagem , Aparelhos Ortodônticos Funcionais , Fenômenos Biomecânicos , Criança , Tomografia Computadorizada de Feixe Cônico , Módulo de Elasticidade , Feminino , Humanos , Masculino , Má Oclusão Classe II de Angle/fisiopatologia , Má Oclusão Classe II de Angle/terapia , Côndilo Mandibular/diagnóstico por imagem , Côndilo Mandibular/fisiopatologia , Maxila/diagnóstico por imagem , Articulação Temporomandibular/diagnóstico por imagem , Articulação Temporomandibular/fisiopatologia
10.
Sci Rep ; 7(1): 2988, 2017 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-28592796

RESUMO

Apolipoprotein A-I (apoA-I) undergoes a large conformational reorganization during remodeling of high-density lipoprotein (HDL) particles. To detect structural transition of apoA-I upon HDL formation, we developed novel monoclonal antibodies (mAbs). Splenocytes from BALB/c mice immunized with a recombinant human apoA-I, with or without conjugation with keyhole limpet hemocyanin, were fused with P3/NS1/1-Ag4-1 myeloma cells. After the HAT-selection and cloning, we established nine hybridoma clones secreting anti-apoA-I mAbs in which four mAbs recognize epitopes on the N-terminal half of apoA-I while the other five mAbs recognize the central region. ELISA and bio-layer interferometry measurements demonstrated that mAbs whose epitopes are within residues 1-43 or 44-65 obviously discriminate discoidal and spherical reconstituted HDL particles despite their great reactivities to lipid-free apoA-I and plasma HDL, suggesting the possibility of these mAbs to detect structural transition of apoA-I on HDL. Importantly, a helix-disrupting mutation of W50R into residues 44-65 restored the immunoreactivity of mAbs whose epitope being within residues 44-65 against reconstituted HDL particles, indicating that these mAbs specifically recognize the epitope region in a random coil state. These results encourage us to develop mAbs targeting epitopes in the N-terminal residues of apoA-I as useful probes for monitoring formation and remodeling of HDL particles.


Assuntos
Anticorpos Monoclonais/metabolismo , Apolipoproteína A-I/química , Apolipoproteína A-I/metabolismo , Lipoproteínas HDL/metabolismo , Animais , Anticorpos Monoclonais/isolamento & purificação , Humanos , Camundongos Endogâmicos BALB C , Ligação Proteica , Conformação Proteica
11.
Biochim Biophys Acta ; 1858(6): 1339-49, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27003128

RESUMO

The first step of cell membrane penetration of arginine peptides is thought to occur via electrostatic interactions between positive charges of arginine residues and negative charges of sulfated glycosaminoglycans (GAGs) on the cell surface. However, the molecular interaction of arginine peptides with GAG still remains unclear. Here, we compared the interactions of several arginine peptides of Tat, R8, and Rev and their analogues with heparin in relation to the cell membrane penetration efficiency. The high-affinity binding of arginine peptides to heparin was shown to be driven by large favorable enthalpy contributions, possibly reflecting multidentate hydrogen bondings of arginine residues with sulfate groups of heparin. Interestingly, the lysine peptides in which all arginine residues are substituted with lysine residues exhibited negligible binding enthalpy despite of their considerable binding to heparin. In CHO-K1 cells, arginine peptides exhibited a great cell-penetrating ability whereas their corresponding lysine peptides did not penetrate into cells. The degree of cell penetration of arginine peptides markedly decreased by the chlorate treatment of cells which prevents the sulfation of GAG chains. Significantly, the cell penetration efficiency of arginine peptides was found to be correlated with the favorable enthalpy of binding to heparin. These results suggest that the enthalpy-driven strong interaction with sulfated GAGs such as heparan sulfate plays a critical role in the efficient cell membrane penetration of arginine peptides.


Assuntos
Arginina/química , Permeabilidade da Membrana Celular , Glicosaminoglicanos/química , Peptídeos/química , Sulfatos/química , Termodinâmica , Sequência de Aminoácidos , Animais , Células CHO , Cricetinae , Cricetulus , Heparina/química , Dados de Sequência Molecular , Espectroscopia de Prótons por Ressonância Magnética , Lipossomas Unilamelares
12.
Brain Tumor Pathol ; 32(3): 176-83, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25665548

RESUMO

Glioma stem cells (GSCs) have the capacity to repopulate tumors and mediate resistance to radiotherapy and chemotherapy. The Notch signaling pathway is important in proliferation, stem cell maintenance, cell differentiation, and tumorigenesis in GSCs. In this study, we compared CD133, Notch, and VEGF expressions in histological sections of primary and recurrent glioblastomas after radiotherapy and chemotherapy. In vitro study, the γ-secretase inhibitor inhibited NICD, Hes1 and pVEGFR2 expressions in GSCs. GSCs cultured under endothelial conditions undergo endothelial differentiation. Tumor samples were collected from 27 patients at the time of tumor recurrence. We used immunohistochemical techniques to compare expression of CD133, Notch-1 and VEGF. Expressions of CD133-, Notch-1-, and VEGF-positive glioma cells were higher in recurrent glioblastoma after radiotherapy and chemotherapy. To determine the clinical importance of Notch-1 expression in glioblastoma, we analyzed 15 patients who had received bevacizumab therapy followed by a second surgery at recurrence. OS was significantly longer in cases with Notch-1 negativity (8.8 months) than in those with I Notch-1 positivity (6.8 months). We noted that GSCs have the potential for endothelial differentiation with Notch activity. We believe that Notch-1 is a potential target and/or biomarker for antiangiogenic treatments.


Assuntos
Neoplasias Encefálicas/genética , Neoplasias Encefálicas/terapia , Quimiorradioterapia , Regulação Neoplásica da Expressão Gênica/genética , Expressão Gênica/genética , Glioblastoma/genética , Glioblastoma/terapia , Receptor Notch1/genética , Antígeno AC133 , Adulto , Idoso , Inibidores da Angiogênese/uso terapêutico , Antígenos CD/genética , Bevacizumab/uso terapêutico , Linhagem Celular Tumoral , Transformação Celular Neoplásica/genética , Feminino , Glicoproteínas/genética , Humanos , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia , Células-Tronco Neoplásicas/patologia , Peptídeos/genética , Resultado do Tratamento , Fator A de Crescimento do Endotélio Vascular/genética , Adulto Jovem
13.
Biochemistry ; 54(4): 1123-31, 2015 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-25564321

RESUMO

It is thought that apolipoprotein A-I (apoA-I) spontaneously exchanges between high-density lipoprotein (HDL)-bound and lipid-free states, which is relevant to the occurrence of preß-HDL particles in plasma. To improve our understanding of the mechanistic basis for this phenomenon, we performed kinetic and thermodynamic analyses for apoA-I exchange between discoidal HDL-bound and lipid-free forms using fluorescence-labeled apoA-I variants. Gel filtration experiments demonstrated that addition of excess lipid-free apoA-I to discoidal HDL particles promotes exchange of apoA-I between HDL-associated and lipid-free pools without alteration of the steady-state HDL particle size. Kinetic analysis of time-dependent changes in NBD fluorescence upon the transition of NBD-labeled apoA-I from HDL-bound to lipid-free state indicates that the exchange kinetics are independent of the collision frequency between HDL-bound and lipid-free apoA-I, in which the lipid binding ability of apoA-I affects the rate of association of lipid-free apoA-I with the HDL particles and not the rate of dissociation of HDL-bound apoA-I. Thus, C-terminal truncations or mutations that reduce the lipid binding affinity of apoA-I strongly impair the transition of lipid-free apoA-I to the HDL-bound state. Thermodynamic analysis of the exchange kinetics demonstrated that the apoA-I exchange process is enthalpically unfavorable but entropically favorable. These results explain the thermodynamic basis of the spontaneous exchange reaction of apoA-I associated with HDL particles. The altered exchangeability of dysfunctional apoA-I would affect HDL particle rearrangement, leading to perturbed HDL metabolism.


Assuntos
Apolipoproteína A-I/metabolismo , Lipoproteínas HDL/metabolismo , Termodinâmica , Apolipoproteína A-I/farmacocinética , Cinética , Lipoproteínas HDL/farmacocinética , Ligação Proteica/fisiologia , Engenharia de Proteínas/métodos
14.
Surg Res Pract ; 2014: 898510, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25379565

RESUMO

In 1999, a 50-year-old woman underwent ventriculoperitoneal (VP) shunt surgery for hydrocephalus after subarachnoid hemorrhage. She was hospitalized for fever and recurrent systemic seizures in November 2006. Head computed tomography (CT) showed only old changes. The seizures and fever were controlled by medicinal therapy. However, in December, her consciousness level suddenly decreased, and she showed progressive lower abdominal distension. Head CT showed marked ventriculomegaly, and abdominal CT showed a giant cystic mass at the shunt-tube tip in the lower abdominal cavity. Because thick pus was aspirated from the intra-abdominal mass, we diagnosed the patient with acute obstructive hydrocephalus due to an infected abdominal pseudocyst. Laparotomy and direct cyst drainage were performed, and antibiotic therapy against Streptococcus, the causative pathogen, was administered. The VP shunt tube was replaced. The postoperative course was uneventful, and postoperative CT showed hydrocephalus improvement and no pseudocyst recurrence. Abdominal pseudocysts, which are rare after VP shunt surgeries, usually occur after the subacute postoperative course in younger cerebral hemorrhagic cases. Our case was quite rare because the cyst developed in the chronic phase in an older patient and was caused by streptococcal infection. The cyst components should be examined before cyst drainage when choosing surgical strategies.

15.
Ther Apher Dial ; 18 Suppl 1: 2-8, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24953759

RESUMO

We previously conducted a multicenter study enrolling 101 dialysis patients with hyperphosphatemia in which lanthanum carbonate (LC) was administered for 2 years. In this study, the administration has been continued for an additional year, and we have evaluated the long-term (a total of 3 years) effects of LC. The average serum phosphorus (P) level was 6.05 mg/dL at the start and decreased to 5.84 mg/dL after 3 years, but no significant differences were observed at both points. The average serum corrected calcium (Ca) level significantly reduced after 3 years (P < 0.001). As results of evaluating the achievement rates with the management target values of serum P, Ca and intact parathyroid hormone (PTH) stated in the Japanese guideline, the achievement rates increased after 3 years. From these results, LC is considered to be a useful P binder that can be used for long-term treatment of hyperphosphatemia, without causing a Ca load.


Assuntos
Hiperfosfatemia/tratamento farmacológico , Falência Renal Crônica/terapia , Lantânio/uso terapêutico , Diálise Renal/métodos , Idoso , Cálcio/sangue , Feminino , Humanos , Hiperfosfatemia/etiologia , Lantânio/administração & dosagem , Masculino , Pessoa de Meia-Idade , Hormônio Paratireóideo/sangue , Fósforo/sangue , Fatores de Tempo , Resultado do Tratamento
16.
Ther Apher Dial ; 17 Suppl 1: 2-8, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23586506

RESUMO

Long-term efficacy of lanthanum carbonate on hyperphosphatemia was examined in multicenter dialysis patients. Outcome and efficacy after 2 years was investigated in 101 patients who had undergone lanthanum carbonate administration. Thirty-three cases dropped out by the 2-year point; patients undergoing at least 2 years of administration totaled 68. Reasons for dropping out were as follows: improvement of hyperphosphatemia, nine cases; changing hospitals, seven cases; medical complications, five cases; digestive symptoms, four cases; poor compliance, four cases; parathyroidectomy, two cases; death, two cases. The mean dosage was increased from initial daily dosage of 744 mg to 1266 mg after 1 year, and to 1246 mg after 2 years. Serum phosphate concentration decreased significantly from the initial 6.15 mg to 5.57 mg/dL after 1 year, and to 5.45 mg/dL after 2 years. Although a lowering trend was observed in corrected calcium levels, the difference was not significant. Parathyroid hormone was unchanged. Achievement rate of Japanese Society for Dialysis Therapy (JSDT) management target values for both phosphorus and calcium improved from 32.7% to 50.0% after 1 year, and to 56.5% after 2 years. Lanthanum carbonate is useful as a therapeutic tool for hyperphosphatemia over long durations.


Assuntos
Hiperfosfatemia/tratamento farmacológico , Falência Renal Crônica/terapia , Lantânio/uso terapêutico , Diálise Renal/métodos , Idoso , Cálcio/sangue , Relação Dose-Resposta a Droga , Feminino , Humanos , Hiperfosfatemia/etiologia , Lantânio/administração & dosagem , Masculino , Pessoa de Meia-Idade , Hormônio Paratireóideo/sangue , Fosfatos/sangue , Fatores de Tempo , Resultado do Tratamento
17.
ScientificWorldJournal ; 2013: 128916, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24385868

RESUMO

An actuator is required to change its speed and force depending on the situation. Using multiple actuators for one driving axis is one of the possible solutions; however, there is an associated problem of output power matching. This study proposes a new active joint mechanism using multiple actuators. Because the actuator is made of a flexible bag, it does not interfere with other actuators when it is depressurized. The proposed joint achieved coordinated motion of multiple actuators. This report also discusses a new actuator which has dual cylindrical structure. The cylinders are composed of flexible bags with different diameters. The joint torque is estimated based on the following factors: empirical formula for the flexible actuator torque, geometric relationship between the joint and the actuator, and the principle of virtual work. The prototype joint mechanism achieves coordinated motion of multiple actuators for one axis. With this motion, small inner actuator contributes high speed motion, whereas large outer actuator generates high torque. The performance of the prototype joint is examined by speed and torque measurements. The joint showed about 30% efficiency at 2.0 Nm load torque under 0.15 MPa air input.


Assuntos
Biomimética , Torque , Desenho de Equipamento , Cinética , Movimento (Física) , Pressão , Estresse Mecânico
18.
Case Rep Med ; 2012: 120867, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22966233

RESUMO

A 54-year-old woman presented to our hospital with progressive motor weakness of the right arm. She had a medical history of systemic lupus erythematosus (SLE) and hypothyroidism. Magnetic resonance imaging indicated a watershed infarction of the left hemisphere. Cervical echogram indicated severe stenosis of the internal carotid artery (ICA) without wall thickening. Cerebral angiography indicated left ICA occlusion, development of unilateral moyamoya vessels, and leptomeningeal anastomosis. Encephaloduroarteriosynangiosis (EDAS) was performed after cerebral (99) (m)Technetium-ethyl-cysteinate-dimer single-photon emission computed tomography indicated a decreased cerebral blood flow, diminished cerebrovascular perfusion reserve. Motor weakness finally disappeared 6 months after surgery. Moyamoya syndrome is a rare complication of both SLE and hypothyroidism, and the surgical indication remains controversial. By evaluating the decreased cerebral perfusion reserve capacity and the existence of leptomeningeal anastomosis, EDAS could be an efficient method for the treatment of moyamoya syndrome associated with SLE and hypothyroidism.

19.
J Biochem ; 151(5): 483-92, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22427434

RESUMO

Ferredoxin (Fd), which plays a pivotal role in photosynthesis as an electron carrier, forms a transient complex with various Fd-dependent enzymes, such as nitrite reductase (NiR), to achieve efficient intermolecular electron transfer. We studied the protein-protein interaction of Fd and NiR by NMR spectroscopy and determined three acidic regions of Fd to be major sites for the interaction with NiR, indicating that the complex is stabilized through electrostatic interaction. During this study, we found Fds from higher plant and cyanobacterium, in spite of their high structural similarities including the above acidic regions, differ remarkably in the interaction with cyanobacterial NiR. In activity assay of NiR, K(m) value for maize Fd (74.6 µM) was 9.6 times larger than that for Leptolyngbya boryana Fd (7.8 µM). The two Fds also showed a similar difference in binding assay to NiR-immobilized resin. Comparative site-specific mutagenesis of two Fds revealed that their discriminative ability for the interaction with NiR is attributed mainly to non-charged residues in the peripheral region of [2Fe-2S] cluster. These non-charged residues are conserved separately between Fds of plant and cyanobacterial origins. Our data highlight that intermolecular force(s) other than electrostatic attraction is(are) also crucial for the molecular interaction between Fd and partner enzyme.


Assuntos
Cianobactérias/química , Ferredoxinas/química , Nitrito Redutases/química , Ressonância Magnética Nuclear Biomolecular , Zea mays/química , Cristalografia por Raios X , Cianobactérias/enzimologia , Ferredoxinas/genética , Modelos Moleculares , Nitrito Redutases/metabolismo , Ligação Proteica
20.
Jpn J Antibiot ; 64(3): 125-69, 2011 Jun.
Artigo em Japonês | MEDLINE | ID: mdl-21861307

RESUMO

Bacteria isolated from surgical infections during the period from April 2009 to March 2010 were investigated in a multicenter study in Japan, and the following results were obtained. In this series, 671 strains including 16 strains of Candida spp. were isolated from 174 (79.1%) of 220 patients with surgical infections. Four hundred and eleven strains were isolated from primary infections, and 244 strains were isolated from surgical site infection. From primary infections, anaerobic Gram-negative bacteria were predominant, followed by aerobic Gram-negative bacteria, while from surgical site infection aerobic Gram-positive bacteria were predominant, followed by anaerobic Gram-negative bacteria. Among aerobic Gram-positive bacteria, the isolation rate of Enterococcus spp. was highest, followed by Streptococcus spp., and Staphylococcus spp. in this order, from primary infections, while Enterococcus spp. was highest, followed by Staphylococcus spp. from surgical site infection. Among aerobic Gram-negative bacteria, Escherichia coli was the most predominantly isolated from primary infections, followed by Klebsiella pneumoniae, Enterobacter cloacae and Pseudomonas aeruginosa, in this order, and from surgical site infection, E. coli was most predominantly isolated, followed by P. aeruginosa and E. cloacae. Among anaerobic Gram-positive bacteria, the isolation rate of Eggerthella lenta was the highest from primary infections, followed by Parvimonas micra, Streptococcus constellatus and Finegoldia magna, and from surgical site infection, E. lenta was most predominantly isolated. Among anaerobic Gram-negative bacteria, the isolation rate of Bilophila wadsworthia was the highest from primary infections, followed by Bacteroides fragilis, Bacteroides ovatus and Bacteroides thetaiotaomicron, and from surgical site infection, B. fragilis was most predominantly isolated, followed by B. ovatus, B. wadsworthia and B. thetaiotaomicron, in this order. In this series, we noticed no vancomycin-resistant Gram-positive cocci, nor multidrug-resistant P. aeruginosa. We should carefully follow up B. wadsworthia which was resistant to various antibiotics, and also Bacteroides spp. which was resistant to many beta-lactam antibiotics.


Assuntos
Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Bactérias/isolamento & purificação , Infecção da Ferida Cirúrgica/microbiologia , Farmacorresistência Bacteriana , Humanos , Estações do Ano , Fatores de Tempo
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