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1.
Proc Natl Acad Sci U S A ; 121(16): e2322211121, 2024 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-38593080

RESUMO

Adenosine 3',5'-cyclic monophosphate (cAMP) is a universal signaling molecule that acts as a second messenger in various organisms. It is well established that cAMP plays essential roles across the tree of life, although the function of cAMP in land plants has long been debated. We previously identified the enzyme with both adenylyl cyclase (AC) and cAMP phosphodiesterase (PDE) activity as the cAMP-synthesis/hydrolysis enzyme COMBINED AC with PDE (CAPE) in the liverwort Marchantia polymorpha. CAPE is conserved in streptophytes that reproduce with motile sperm; however, the precise function of CAPE is not yet known. In this study, we demonstrate that the loss of function of CAPE in M. polymorpha led to male infertility due to impaired sperm flagellar motility. We also found that two genes encoding the regulatory subunits of cAMP-dependent protein kinase (PKA-R) were also involved in sperm motility. Based on these findings, it is evident that CAPE and PKA-Rs act as a cAMP signaling module that regulates sperm motility in M. polymorpha. Therefore, our results have shed light on the function of cAMP signaling and sperm motility regulators in land plants. This study suggests that cAMP signaling plays a common role in plant and animal sperm motility.


Assuntos
Marchantia , Masculino , Animais , Marchantia/genética , AMP Cíclico/metabolismo , Motilidade dos Espermatozoides/genética , Sementes/metabolismo , Adenilil Ciclases/metabolismo , Espermatozoides/metabolismo
2.
Artigo em Inglês | MEDLINE | ID: mdl-37681766

RESUMO

Japan has the world's largest old population ratio; thus, aging is an urgent societal issue. As global trends seem to be following Japan's social changes, there is an emphasis on municipalities becoming more age-friendly. Hence, we examine the age-friendliness of 135 Japanese municipalities, selecting 240 resident architectural designers and constructors to assess their municipalities using the Age-Friendly Cities and Communities Questionnaire (AFCCQ). The findings indicate that Japan lacks "outdoor spaces and buildings". Additionally, the evaluation of "housing", "community support and health services", and "transportation" in populated municipalities in the past five years was found to be significantly higher than that in depopulated ones. Age-friendliness is significantly affected by the AFCCQ total score (hereafter, Score) based on "housing", "social participation", "community support and health services", "transportation", and "financial situation" evaluations. High specificity (0.939) was found when the score was treated as a marker of depopulation; an age-friendly approach is a necessary condition for preventing depopulation. Furthermore, a lack of "communication and information" was observed in municipalities with a higher rate of single-person households aged 65 years and older. Therefore, resident architectural designers' and constructors' assessments, combined with the AFCCQ, will be a powerful tool for evaluating the age-friendliness of municipalities.


Assuntos
Envelhecimento , Arquitetura , Planejamento de Cidades , Apoio Comunitário , População do Leste Asiático , Planejamento Ambiental , Humanos , Cidades , Comunicação , Meios de Transporte , Japão , Crescimento Demográfico
3.
Commun Biol ; 6(1): 697, 2023 07 07.
Artigo em Inglês | MEDLINE | ID: mdl-37420035

RESUMO

The order Parmales (class Bolidophyceae) is a minor group of pico-sized eukaryotic marine phytoplankton that contains species with cells surrounded by silica plates. Previous studies revealed that Parmales is a member of ochrophytes and sister to diatoms (phylum Bacillariophyta), the most successful phytoplankton group in the modern ocean. Therefore, parmalean genomes can serve as a reference to elucidate both the evolutionary events that differentiated these two lineages and the genomic basis for the ecological success of diatoms vs. the more cryptic lifestyle of parmaleans. Here, we compare the genomes of eight parmaleans and five diatoms to explore their physiological and evolutionary differences. Parmaleans are predicted to be phago-mixotrophs. By contrast, diatoms have lost genes related to phagocytosis, indicating the ecological specialization from phago-mixotrophy to photoautotrophy in their early evolution. Furthermore, diatoms show significant enrichment in gene sets involved in nutrient uptake and metabolism, including iron and silica, in comparison with parmaleans. Overall, our results suggest a strong evolutionary link between the loss of phago-mixotrophy and specialization to a silicified photoautotrophic life stage early in diatom evolution after diverging from the Parmales lineage.


Assuntos
Diatomáceas , Estramenópilas , Diatomáceas/genética , Estramenópilas/genética , Fitoplâncton/metabolismo , Genoma , Dióxido de Silício
4.
Aging Clin Exp Res ; 35(5): 987-994, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36869197

RESUMO

BACKGROUND: Some patients with minor cognitive impairment can revert to normal cognition if intervention is implemented early. Dance video games as multi-task training have shown beneficial effects on cognitive and physical functions in older adults. AIMS: This study aimed to elucidate the effects of dance video game training on cognitive functions and prefrontal cortex activity in older adults with and without mild cognitive impairment. METHODS: A single-arm trial was used for this study. The participants were divided based on the Japanese version of Montreal Cognitive Assessment scores into the mild cognitive impairment (n = 10) and normal cognitive function (n = 11) groups. Dance video game training was performed 60 min/day, 1 day/week, for a total of 12 weeks. Neuropsychological assessments, prefrontal cortex activity using functional near-infrared spectroscopy, and step performance of dance video game were recorded at pre- and post-intervention. RESULTS: Dance video game training significantly improved the Japanese version of Montreal Cognitive Assessment score (p < 0.05), and tendency toward improvement was observed in the trail making test in the mild cognitive impairment group. The dorsolateral prefrontal cortex activity in the Stroop color word test was significantly increased in the mild cognitive impairment group (p < 0.05) after dance video game training. CONCLUSIONS: Dance video game training improved cognitive function and increased prefrontal cortex activity in the mild cognitive impairment group.


Assuntos
Disfunção Cognitiva , Dança , Jogos de Vídeo , Humanos , Idoso , Vida Independente , Cognição , Disfunção Cognitiva/terapia , Jogos de Vídeo/psicologia
5.
J Phycol ; 58(5): 631-642, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35796617

RESUMO

Pleurosira laevis is a salt-tolerant diatom distributed around the world. The valve of P. laevis has distinct structures called ocelli, which are sharply defined areas with fine, densely packed pores. Two formae of this diatom, P. laevis f. laevis and P. laevis f. polymorpha, are distinguished from each other by their flat or dome-shaped valve faces and degree of elevation of the ocelli, respectively. In this study, we established 4 strains of P. laevis isolated from freshwaters or coastal areas in Japan and the United States, and tracked the formation of newly formed valves with the fluorescent SDV-specific dye PDMPO in culture under several salinity conditions. The result clearly demonstrated the morphological plasticity of the valves, controlled by environmental salinity. The laevis form and polymorpha form valves were produced at salinities of 2 and 7, respectively. The salinity thresholds dictating the morphological plasticity of the valve were consistent in all 4 strains. A similar morphology to the polymorpha form was reproduced in a freshwater medium with the addition of sorbitol, suggesting that osmotic pressure plays a key role in this morphological plasticity. The highly reproducible and easily manipulated change in morphology makes this diatom an ideal model for lab experiments focusing on the molecular and genetic factors involved with valve morphogenesis.


Assuntos
Diatomáceas , Salinidade , Água Doce , Pressão Osmótica , Sorbitol
6.
J Gen Appl Microbiol ; 67(5): 207-213, 2021 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-34248085

RESUMO

A unicellular cyanobacterium that produces a large amount of exopolysaccharide (EPS) was isolated. The isolate, named Chroococcus sp. FPU101, grew between 20 and 30°C and at light intensities between 10 and 80 µmol m-2 s-1. Purified EPS from Chroococcus sp. FPU101 had a molecular size of 5.9 × 103 kDa and contained galactose, rhamnose, fucose, xylose, mannose, glucose, galacturonic acid, and glucuronic acid at a molar ratio of 17.2:15.9:14.1:11.0:9.6:9.5:13.0:9.7. The EPS content significantly increased when the NaCl concentration in the medium was increased from 1.7 to 100 mM. However, high NaCl concentrations did not significantly affect the molecular size or chemical composition of the EPS. The genes wza, wzb, wzc, wzx, wzy, and wzz that are involved in EPS synthesis were conserved in the genome of Chroococcus sp. FPU101, which was sequenced in this study. These results suggest that the Wzy-dependent pathway is potentially involved in EPS production in this organism.


Assuntos
Cianobactérias/fisiologia , Genoma Bacteriano , Polissacarídeos Bacterianos/química , Cianobactérias/química , Cianobactérias/genética , Polissacarídeos Bacterianos/biossíntese , Polissacarídeos Bacterianos/genética
7.
Nagoya J Med Sci ; 83(1): 31-40, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33727735

RESUMO

Phase angle has been suggested as a useful, noninvasive, and objective index to evaluate the nutritional status of older people. However, there are no studies analyzing the relationship between nutritional status and phase angle in older patients, according to sex. The aim of this study was to clarify the relationship between phase angle and malnutrition, and to calculate cut-off points of malnutrition with phase angle in older inpatients, according to sex. This study was a retrospective cross-sectional study. Participants were older inpatients of a rehabilitation unit, and data within 1 week of hospitalization were collected from the medical records. We collected data of demographics, phase angle, and the Geriatric Nutritional Risk Index. Phase angle was measured with InBody S10. To confirm whether phase angle is an important factor in predicting malnutrition, we conducted binary logistic regression analysis. In addition, to determine the cut-off points of malnutrition in older inpatients, we used the receiver operator characteristic (ROC) curve. Participants included 59 men (mean age 76.5 years) and 101 women (mean age 78.8 years). As a result of statistical analysis, phase angle was an important factor related to malnutrition in both male and female inpatients. Our findings showed that cut-off points of 4.03 degrees (sensitivity; 87.0%, specificity; 75.9%) in male patients and 3.65 degrees (sensitivity; 78.6%, specificity; 60.5%) in female patients could be used to predict malnutrition. The results of this study suggest that phase angle may be useful as an indicator to predict the nutritional status of older inpatients.


Assuntos
Membrana Celular/fisiologia , Desnutrição/diagnóstico , Desnutrição/fisiopatologia , Estado Nutricional , Idoso , Idoso de 80 Anos ou mais , Estudos Transversais , Impedância Elétrica , Feminino , Nível de Saúde , Humanos , Masculino , Músculo Esquelético/fisiopatologia , Valor Preditivo dos Testes , Curva ROC , Estudos Retrospectivos , Fatores Sexuais
8.
Disabil Rehabil ; 43(14): 2019-2023, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-31739692

RESUMO

AIM: Few studies of depression have examined older inpatients with fracture and preexisting cognitive impairment. The current study sought to confirm whether depression affects the condition of older inpatients with fracture who also have cognitive impairment, and to investigate the extent to which depression affects activities of daily living. METHODS: This was a retrospective cross-sectional study. The subjects were older inpatients with fracture and preexisting cognitive impairment. We examined data within 1 week of hospitalization, obtained from medical records. The data included demographic information, the motor Functional Independence Measure, Charlson Comorbidity Index, Mini-Mental State Examination, Geriatric Depression Scale 15, Geriatric Nutritional Risk Index, Skeletal Muscle Index and maximum grip strength test. These variables were compared between the two groups (with and without depression), and multiple regression analysis was performed with the motor Functional Independence Measure as the dependent variable. RESULTS: The subjects were 68 patients. Only the motor Functional Independence Measure was significantly lower in the depression group than the non-depression group. Multiple regression analysis confirmed that depression strongly affected activities of daily living. CONCLUSIONS: In considering the recovery of older inpatients with fracture and preexisting cognitive impairment, it is important to take the effects of depression into account.Implications for rehabilitationThe number of older fracture inpatients with cognitive impairment is predicted to increase, and such patients have a high prevalence of depression.Depression strongly affected Activities of Daily Living in older inpatients with fracture and pre-existing cognitive impairment.Focusing on depression assessment and intervention is important for rehabilitation of older fracture inpatients with cognitive impairment.


Assuntos
Atividades Cotidianas , Disfunção Cognitiva , Idoso , Disfunção Cognitiva/epidemiologia , Estudos Transversais , Depressão/epidemiologia , Avaliação Geriátrica , Humanos , Pacientes Internados , Estudos Retrospectivos
9.
J Phycol ; 55(1): 196-203, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30320892

RESUMO

Triparma laevis f. inornata is a unicellular alga belonging to the Bolidophyceae, which is most closely related to diatoms. Like diatoms, T. laevis f. inornata has a siliceous cell wall. The cell wall of T. laevis f. inornata consists of four round plates (three shields and one ventral plate) and one dorsal and three girdle plates. But, unlike diatoms, T. laevis f. inornata cells can grow when concentrations of silica are depleted. We took advantage of this ability, using TEM to study the ontogeny of the siliceous plate, pattern center formation, and development. Two types of pattern centers (annulus and sternum) were observed in the early and middle stage of plate formation. During their formation, the annuli were initially crescent-shaped but eventually their ends fused to make a ring. Only outward silica deposition of the branching ribs occurred on the growing annulus until it became a ring, resulting in an unfilled circle inside the annulus. The pattern center of the shield plate was always an annulus, but in ventral plates both annulus and sternum were observed. The annuli and sterna in T. laevis f. inornata round plates were very similar to the annuli and sterna in diatom valves. These results suggested that the round plates of Parmales are homologous to diatom valves. This information on the plate ontogeny of T. laevis f. inornata provides new insights into the evolution of the siliceous cell wall in the Parmales and diatoms.


Assuntos
Diatomáceas , Estramenópilas , Parede Celular , Dióxido de Silício
10.
J Phys Ther Sci ; 30(10): 1305-1309, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30349169

RESUMO

[Purpose] This study aimed to ascertain whether ankle stretching combined with arm cycling compared with that without arm cycling results in greater improvement in maximum dorsiflexion range of motion (ROM), calf muscle stiffness, and gait velocity in the affected limb of patients with stroke. [Participants and Methods] Random ABAB reversal design was used in this study involving nine patients with stroke. Participants performed 10 min of ankle plantar flexor stretching through weight bearing using the tilt table under the following 2 conditions: with or without arm cycling at 60 revolutions per minute. Pre- and post-stretching maximum ROM and passive plantar flexion torque were measured using a custom-made passive torque indicator. Stiffness was calculated based on passive torque-angle relationships. [Results] Maximum ROM and stiffness significantly improved after stretching in both conditions, whereas no changes in gait velocity were found. The difference in pre- and post-stretching stiffness was significantly greater in the stretching with arm cycling group. Change in maximum ROM showed no difference between both stretching conditions. [Conclusion] This study indicates that ankle plantar flexor stretching combined with arm cycling was more effective than that without cycling in improving calf muscle stiffness in the affected limb of patients with stroke.

11.
Neurosci Res ; 120: 36-44, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28284708

RESUMO

Manipulation of visual experience can considerably modify visual responses of visual cortical neurons even in adulthood in the mouse, although the modification is less profound than that observed during the critical period. Our previous studies demonstrated that low-frequency (2Hz) stimulation for 15min applied to layer 4 induces T-type Ca2+ channel-dependent long-term potentiation (LTP) at excitatory synapses in layer 2/3 neurons of visual cortex during the critical period. In this study, we investigated whether low-frequency stimulation could induce synaptic plasticity in adult mice. We found that 2Hz stimulation induced LTP of extracellular field potentials evoked by stimulation of layer 4 in layer 2/3 in adulthood as during the critical period. LTP in adulthood was blocked by L-type, but not T-type, Ca2+ channel antagonists, whereas LTP during the critical period was blocked by T-type, but not L-type, Ca2+ channel antagonists. This developmental change in LTP was prevented by dark rearing. Under pharmacological blockade of GABAA receptors, T-type Ca2+ channel-dependent LTP occurred, whereas L-type Ca2+ channel-dependent LTP did not occur. These results suggest that different forms of synaptic plasticity can contribute separately to experience-dependent modification of visual responses during the critical period and in adulthood.


Assuntos
Potenciação de Longa Duração , Córtex Visual/fisiologia , Animais , Canais de Cálcio Tipo L/fisiologia , Canais de Cálcio Tipo T/fisiologia , Estimulação Elétrica , Camundongos Endogâmicos C57BL , Privação Sensorial , Córtex Visual/crescimento & desenvolvimento
12.
Clin Pharmacol Drug Dev ; 6(4): 331-342, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27489211

RESUMO

TV-1106 is a human serum albumin genetically fused to recombinant human growth hormone, designed to provide a long-acting alternative to daily growth hormone (GH) injections in patients with GH deficiency. This study investigated the pharmacokinetics, pharmacodynamics, and safety of single subcutaneous doses of TV-1106 (7.5, 15, 50, and 100 mg) in Japanese (n = 44) and caucasian (n = 44) healthy subjects. TV-1106 pharmacokinetics and pharmacodynamics were comparable in Japanese and caucasian populations. TV-1106 demonstrated relatively slow absorption (median tmax , 10-30 hours) and a mean elimination half-life of 26-36 hours. Apparent clearance and volume of distribution decreased with increasing TV-1106 doses in both populations and appeared to increase more than dose proportionality across the tested doses. Insulin-like growth factor-1 (IGF-1) and IGF binding protein-3 (IGFBP-3) increased in a dose-related manner, with maximum responses observed at 33-96 and 42-109 hours, respectively. IGF-1 and IGFBP-3 returned to baseline values at 168 hours following 7.5 and 15 mg of TV-1106, and 336 hours following 50 and 100 mg of TV-1106. TV-1106 appeared safe in both populations. There was no evidence of differences in pharmacokinetics, pharmacodynamics, or safety of TV-1106 between Japanese and caucasian populations. The data also demonstrate long-acting growth hormone properties of TV-1106 and support its potential for once-weekly dosing.


Assuntos
Hormônio do Crescimento Humano/genética , Proteínas Recombinantes de Fusão/farmacocinética , Albumina Sérica Humana/genética , Adulto , Povo Asiático , Relação Dose-Resposta a Droga , Feminino , Voluntários Saudáveis , Hormônio do Crescimento Humano/metabolismo , Humanos , Injeções Subcutâneas , Proteína 3 de Ligação a Fator de Crescimento Semelhante à Insulina/metabolismo , Fator de Crescimento Insulin-Like I/metabolismo , Masculino , Proteínas Recombinantes de Fusão/administração & dosagem , Proteínas Recombinantes de Fusão/efeitos adversos , Albumina Sérica Humana/metabolismo , População Branca , Adulto Jovem
13.
Protoplasma ; 254(1): 461-471, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27048177

RESUMO

The parmalean algae possess a siliceous wall and represent the sister lineage of diatoms; they are thought to be a key group for understanding the evolution of diatoms. Diatoms possess well-characterized and unique mitotic structures, but the mitotic apparatus of Parmales is still unknown. We observed the microtubule (MT) array during interphase and mitosis in Triparma laevis using TEM. The interphase cells had four or five centrioles (∼80 nm in length), from which MTs emanated toward the cytoplasm. In prophase, the bundle of MTs arose at an extranuclear site. The position of centrioles with respect to an MT bundle changed during its elongation. Centrioles were observed on the lateral side of a shorter MT bundle (∼590 nm) and on either side of an extended MT bundle (∼700 nm). In metaphase, the spindle consisted of two types of MTs-MT bundle that passed through a cytoplasmic tunnel in the center of the nucleus and single MTs (possibly kinetochore MTs) that extended from the poles into the nucleus. The nuclear envelope disappeared only at the regions where the kinetochore MTs penetrated. In telophase, daughter chromosomes migrated toward opposite poles, and the MT bundle was observed between segregating chromosomes. These observations showed that MT nucleation does not always occur at the periphery of centrioles through cell cycle and that the spindle of T. laevis has a similar configuration to that of diatoms.


Assuntos
Fuso Acromático/metabolismo , Estramenópilas/metabolismo , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/metabolismo , Células Cultivadas , Centríolos/efeitos dos fármacos , Centríolos/metabolismo , Interfase/efeitos dos fármacos , Metáfase/efeitos dos fármacos , Microtúbulos/efeitos dos fármacos , Microtúbulos/metabolismo , Modelos Biológicos , Silício/farmacologia , Fuso Acromático/efeitos dos fármacos , Estramenópilas/citologia , Estramenópilas/ultraestrutura
14.
Arch Gerontol Geriatr ; 60(2): 244-51, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25482957

RESUMO

This study investigated the effects of balance exercise combined with whole-body vibration (WBV) on step performance and lower limb muscle activity during simulated forward falls using the tether-release method in older women. Twenty older women were assigned to either a WBV plus balance exercise group (WBV, n=10) or a balance exercise without vibration group (standard balance exercise group [STE], n=10). WBV performed weight-bearing exercises on a WBV platform combined with other balance exercises as a home program, whereas STE performed the same exercises without WBV. The exercise volume was equal in both intervention groups (3×/week for 12 weeks×30 min/session). The EMG and kinematic data of the stepping leg from the balance recovery step were examined before and after the intervention. While both groups extended step length during forward falls after the intervention, only WBV increased step velocity. EMG analysis of the balance recovery step showed that both groups increased peak EMG of knee flexor and extensor muscles after intervention. After intervention, WBV increased peak EMG of the plantar flexors, which are used to exert the push-off forces just before the leg swing. Balance exercise in older women resulted in significant improvements in the balance recovery step after a simulated forward fall. WBV also had the additional benefit of improved step velocity, which was reflected in increased activity of the plantar flexors in the stepping leg.


Assuntos
Terapia por Exercício/métodos , Exercício Físico , Força Muscular , Equilíbrio Postural , Vibração , Idoso , Idoso de 80 Anos ou mais , Eletromiografia , Extremidades , Feminino , Humanos , Articulação do Joelho , Pessoa de Meia-Idade , Modalidades de Fisioterapia , Projetos Piloto , Resultado do Tratamento , Suporte de Carga
15.
PLoS One ; 9(7): e103289, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25054645

RESUMO

The order Parmales (Heterokontophyta) is a group of small-sized unicellular marine phytoplankton, which is distributed widely from tropical to polar waters. The cells of Parmales are surrounded by a distinctive cell wall, which consists of several siliceous plates fitting edge to edge. Phylogenetic and morphological analyses suggest that Parmales is one of the key organisms for elucidating the evolutionary origin of Bacillariophyceae (diatoms), the most successful heterokontophyta. The effects of silicon-limitation on growth and morphogenesis of plates were studied using a strain of Triparma laevis NIES-2565, which was cultured for the first time in artificial sea water. The cells of T. laevis were surrounded by eight plates when grown with sufficient silicon. However, plate formation became incomplete when cells were cultured in a medium containing low silicate (ca. <10 µM). Cells finally lost almost all plates in a medium containing silicate concentrations lower than ca. 1 µM. However, silicon-limitation did not affect growth rate; cells continued to divide without changing their growth rate, even after all plates were lost. Loss of plates was reversible; when cells without plates were transferred to a medium containing sufficient silicate, regeneration of shield and ventral plates was followed by the formation of girdle and triradiate plates. The results indicate that the response to silicon-limitation of T. laevis is different from that of diatoms, where cell division becomes inhibited under such conditions.


Assuntos
Diatomáceas/crescimento & desenvolvimento , Fitoplâncton/crescimento & desenvolvimento , Silício/metabolismo , Parede Celular/metabolismo , Parede Celular/ultraestrutura , Diatomáceas/citologia , Diatomáceas/ultraestrutura , Fitoplâncton/citologia , Fitoplâncton/ultraestrutura
16.
Aging Clin Exp Res ; 26(2): 213-20, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24104446

RESUMO

BACKGROUND AND AIMS: This study aimed at comparing the patterns of muscle activation used in stepping to regain balance during a forward fall between subjects with and without a history of falling and at identifying the causes of functional deficits in recovery stepping. METHODS: Elderly women with and without a history of falling (fallers: n = 12, mean age ± SD = 82.8 ± 4.5 years; non-fallers: n = 17, age = 81.4 ± 3.4 years) participated in the study. The subjects were suspended in a forward-leaning position by a lean-control cable with a load of 15 % of body weight and instructed to regain standing balance upon release by taking a single step forward. Electromyography (EMG) data were obtained from five lower extremity muscles on the stepping side, and the muscle activation patterns were compared between fallers and non-fallers. RESULTS: Fallers had a shorter step length and slower step velocity than non-fallers. The EMG time-to-peak for the gastrocnemius muscle, which provides push-off prior to foot lift-off, was slower for fallers than for non-fallers, whereas the EMG onset times of the biceps femoris and gastrocnemius muscles were similar between the groups. The fallers exhibited significantly delayed muscle deactivation of the upper leg and increased co-contraction between the rectus femoris and biceps femoris during the stepping phase than did the non-fallers. CONCLUSIONS: These findings suggest that the muscle activation pattern during the regain balance may reflect an inability to step forward rapidly in elderly women with a history of falls.


Assuntos
Acidentes por Quedas , Envelhecimento/fisiologia , Músculo Esquelético/fisiologia , Idoso , Idoso de 80 Anos ou mais , Fenômenos Biomecânicos , Estudos de Casos e Controles , Eletromiografia , Feminino , Marcha/fisiologia , Humanos , Perna (Membro) , Contração Muscular/fisiologia , Músculo Esquelético/fisiopatologia , Equilíbrio Postural/fisiologia , Tempo de Reação/fisiologia , Caminhada/fisiologia
17.
Microbes Environ ; 27(2): 171-8, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22791050

RESUMO

Small cyanobacteria (<2 µm, pico-cyanobacteria) are abundant in waters deeper than the oxic-anoxic zone in the halocline of a saline meromictic lake, Lake Suigetsu, Fukui, Japan. We have isolated 101 strains that were grouped into six groups by means of the phycobiliprotein composition and sequence homology of the intergenic spacer between the 16S and 23S rRNA genes. Significant growth was observed under weak green light (1.5 µmol m⁻² s⁻¹, approx. 460 to 600 nm), whereas the cells died under white light at even moderate intensities. The isolates grew in a wide range of salinities (0.2 to 3.2%). Tolerance to sulfide varied: four groups grew in medium containing sulfide, however, two groups did not. None of the isolates were capable of anoxygenic photosynthetic (PS-II independent photosynthetic) growth using sulfide as an electron donor. All groups were included within fresh and brackish water of Synechococcus/Cyanobium clade, but they were not monophyletic in the 16S rRNA gene-based phylogenetic tree. The physiological properties of pico-cyanobacteria showed that they had the ability to survive in unique physicochemical environments in the halocline of this saline meromictic lake.


Assuntos
Cianobactérias/classificação , Cianobactérias/isolamento & purificação , Microbiologia da Água , Anaerobiose , Análise por Conglomerados , Cianobactérias/citologia , Cianobactérias/fisiologia , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , DNA Espaçador Ribossômico/química , DNA Espaçador Ribossômico/genética , Japão , Lagos , Luz , Microscopia Eletrônica , Dados de Sequência Molecular , Fotossíntese , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Cloreto de Sódio/metabolismo
18.
Eur J Neurosci ; 28(4): 730-43, 2008 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-18657180

RESUMO

Neocortical neuronal circuits are refined by experience during the critical period of early postnatal life. The shift of ocular dominance in the visual cortex following monocular deprivation has been intensively studied to unravel the mechanisms underlying the experience-dependent modification. Synaptic plasticity is considered to be involved in this process. We previously showed in layer 2/3 pyramidal neurons of rat visual cortex that low-frequency stimulation-induced long-term potentiation (LTP) at excitatory synapses, which requires the activation of Ni(2+)-sensitive (R-type or T-type) voltage-gated Ca(2+) channels (VGCCs) for induction, shared a similar age and experience dependence with ocular dominance plasticity. In this study, we examined whether this LTP is involved in ocular dominance plasticity. In visual cortical slices, LTP was blocked by mibefradil, kurtoxin and R-(-)-efonidipine, T-type VGCC blockers, but not by SNX-482, an R-type VGCC blocker, indicating that LTP induction requires T-type VGCC activation. Mibefradil did not affect synaptic transmission even at a dose about 30 times higher than that required for LTP blockade. Therefore, this drug was used to test the effect of T-type VGCC blockade on ocular dominance shift produced by 6 days of monocular deprivation during the critical period using visual evoked potentials (VEPs). Although this monocular deprivation commonly produced both depression of deprived eye responses and potentiation of nondeprived eye responses, only the former change occurred when mibefradil was infused into the visual cortex during monocular deprivation. Mibefradil infusion produced no acute effects on VEPs. These results suggest that T-type VGCC-dependent LTP contributes to the experience-dependent enhancement of visual responses.


Assuntos
Canais de Cálcio Tipo T/metabolismo , Período Crítico Psicológico , Privação Sensorial/fisiologia , Sinapses/fisiologia , Visão Monocular/fisiologia , Córtex Visual/fisiologia , Animais , Bloqueadores dos Canais de Cálcio/farmacologia , Canais de Cálcio Tipo T/genética , Dominância Ocular , Potenciais Evocados Visuais/efeitos dos fármacos , Potenciais Evocados Visuais/fisiologia , Potenciação de Longa Duração/efeitos dos fármacos , Potenciação de Longa Duração/fisiologia , Mibefradil/farmacologia , Plasticidade Neuronal/fisiologia , Ratos , Ratos Long-Evans , Transmissão Sináptica/efeitos dos fármacos , Transmissão Sináptica/fisiologia , Córtex Visual/citologia
19.
Neuron ; 57(6): 905-16, 2008 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-18367091

RESUMO

Cortical pyramidal neurons alter their responses to input signals depending on behavioral state. We investigated whether changes in somatic inhibition contribute to these alterations. In layer 5 pyramidal neurons of rat visual cortex, repetitive firing from a depolarized membrane potential, which typically occurs during arousal, produced long-lasting depression of somatic inhibition. In contrast, slow membrane oscillations with firing in the depolarized phase, which typically occurs during slow-wave sleep, produced long-lasting potentiation. The depression is mediated by L-type Ca2+ channels and GABA(A) receptor endocytosis, whereas potentiation is mediated by R-type Ca2+ channels and receptor exocytosis. It is likely that the direction of modification is mainly dependent on the ratio of R- and L-type Ca2+ channel activation. Furthermore, somatic inhibition was stronger in slices prepared from rats during slow-wave sleep than arousal. This bidirectional modification of somatic inhibition may alter pyramidal neuron responsiveness in accordance with behavioral state.


Assuntos
Dendritos/fisiologia , Inibição Neural/fisiologia , Células Piramidais/citologia , Córtex Visual/citologia , 2-Amino-5-fosfonovalerato/farmacologia , Potenciais de Ação/efeitos dos fármacos , Potenciais de Ação/fisiologia , Potenciais de Ação/efeitos da radiação , Animais , Animais Recém-Nascidos , Bicuculina/análogos & derivados , Bicuculina/farmacologia , Dendritos/efeitos dos fármacos , Relação Dose-Resposta a Droga , Relação Dose-Resposta à Radiação , Estimulação Elétrica/métodos , Antagonistas de Aminoácidos Excitatórios/farmacologia , Antagonistas GABAérgicos/farmacologia , Potenciais Pós-Sinápticos Inibidores/efeitos dos fármacos , Potenciais Pós-Sinápticos Inibidores/fisiologia , Potenciais Pós-Sinápticos Inibidores/efeitos da radiação , Técnicas de Patch-Clamp/métodos , Quinoxalinas/farmacologia , Ratos , Ratos Sprague-Dawley , Venenos de Aranha/farmacologia , Ácido gama-Aminobutírico/farmacologia
20.
Sci Technol Adv Mater ; 9(4): 044208, 2008 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27878025

RESUMO

Thin polycrystalline zinc-doped indium oxide (In2O3-ZnO) films were prepared by post-annealing amorphous films with various weight concentrations x of ZnO in the range 0⩽x ⩽0.06. We have studied the dependences of the resistivity ρ and Hall coefficient on temperature T and magnetic field H in the range 0.5⩽T ⩽300 K, H⩽6 Tfor 350 nm films annealed in air. Films with 0⩽x⩽0.03 show the superconducting resistive transition. The transition temperature Tc is below 3.3 K and the carrier density n is about 1025-1026 m-3. The annealed In2O3-ZnO films were examined by transmission electron microscopy and x-ray diffraction analysis revealing that the crystallinity of the films depends on the annealing time. We studied the upper critical magnetic field Hc2 (T) for the film with x = 0.01. From the slope of dHc2 /dT, we obtain the coherence length ξ (0) ≈ 10 nm at T = 0 K and a coefficient of electronic heat capacity that is small compared with those of other oxide materials.

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