Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 113
Filtrar
1.
Bull Entomol Res ; 107(2): 165-173, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-27573004

RESUMO

The costs and benefits of polyandry are still not well understood. We studied the effects of multiple mating on the reproductive performance of female Brontispa longissima (Coleoptera: Chrysomelidae), one of the most serious pests of the coconut palm, by using three experimental treatments: (1) singly-mated females (single treatment); (2) females that mated 10 times with the same male (repetition treatment); and (3) females that mated once with each of 10 different males (polyandry treatment). Both multiple mating treatments resulted in significantly greater total egg production and the proportion of eggs that successfully hatched (hatching success) than with the single mating treatment. Furthermore, the polyandry treatment resulted in greater total egg production and hatching success than with the repetition treatment. Thus, mate diversity may affect the direct and indirect benefits of multiple mating. Female longevity, the length of the preoviposition period, the length of the period from emergence to termination of oviposition, and the length of the ovipositing period did not differ among treatments. The pronounced fecundity and fertility benefits that females gain from multiple mating, coupled with a lack of longevity costs, apparently explain the extreme polyandry in B. longissima.


Assuntos
Besouros/fisiologia , Aptidão Genética , Comportamento Sexual Animal , Animais , Besouros/genética , Feminino , Variação Genética , Masculino , Reprodução
3.
J Appl Phys ; 115(17): 17B742, 2014 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-24753634

RESUMO

A compact nonvolatile programmable switch (NVPS) using 90 nm CMOS technology together with perpendicular magnetic tunnel junction (p-MTJ) devices is fabricated for zero-standby-power field-programmable gate array. Because routing information does not change once it is programmed into an NVPS, high-speed read and write accesses are not required and a write-control transistor can be shared among all the NVPSs, which greatly simplifies structure of the NVPS. In fact, the effective area of the proposed NVPS is reduced by 40% compared to that of a conventional MTJ-based NVPS. The instant on/off behavior without external nonvolatile memory access is also demonstrated using the fabricated test chip.

4.
J Dent Res ; 91(9): 888-93, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22772363

RESUMO

Because pre-motor neurons targeting trigeminal motoneurons are located in various regions, including the supratrigeminal (SupV) and intertrigeminal (IntV) regions, the principal sensory trigeminal nucleus (PrV), and the region dorsal to the PrV (dRt), a single trigeminal motoneuron may receive differential convergent inputs from these regions. We thus examined the properties of synaptic inputs from these regions to masseter motoneurons (MMNs) and digastric motoneurons (DMNs) in brainstem slice preparations obtained from P1-5 neonatal rats, using whole-cell recordings and laser photolysis of caged glutamate. Photostimulation of multiple regions within the SupV, IntV, PrV, and dRt induced post-synaptic currents (PSCs) in 14 of 19 MMNs and 18 of 26 DMNs. Furthermore, the stimulation of the lateral SupV significantly induced burst PSCs in MMNs more often than low-frequency PSCs in MMNs or burst PSCs in DMNs. Similar results were obtained in the presence of the GABA(A) receptor antagonist SR95531 and the glycine receptor antagonist strychnine. These results suggest that both neonatal MMNs and DMNs receive convergent glutamatergic inputs from the SupV, IntV, PrV, and dRt, and that the lateral SupV sends burst inputs predominantly to the MMNs. Such convergent pre-motoneuronal inputs to trigeminal motoneurons may contribute to the proper execution of neonatal oro-motor functions.


Assuntos
Músculo Masseter/inervação , Neurônios Motores/fisiologia , Músculos do Pescoço/inervação , Transmissão Sináptica/fisiologia , Núcleos do Trigêmeo/fisiologia , Animais , Animais Recém-Nascidos , Ácido Glutâmico/fisiologia , Técnicas de Patch-Clamp , Estimulação Luminosa , Ratos , Ratos Wistar , Receptores de Glutamato/efeitos dos fármacos , Processamento de Sinais Assistido por Computador
5.
Neuroscience ; 166(3): 1008-22, 2010 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-20060035

RESUMO

We previously reported that electrical stimulation of the reticular formation dorsal to the facial nucleus (RdVII) elicited excitatory masseter responses at short latencies and that RdVII neurons were antidromically activated by stimulation of the trigeminal motor nucleus (MoV), suggesting that excitatory premotor neurons targeting the MoV are likely located in the RdVII. We thus examined the properties of synaptic transmission from the RdVII to jaw-closing and jaw-opening motoneurons in horizontal brainstem preparations from developing rats using voltage-sensitive dye, patch-clamp recordings and laser photostimulation. Electrical stimulation of the RdVII evoked optical responses in the MoV. Combined bath application of the non-N-methyl-d-aspartate (non-NMDA) receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), and the NMDA receptor antagonist DL-2-amino-5-phosphonopentanoic acid (APV) reduced these optical responses, and addition of the glycine receptor antagonist strychnine and the GABA(A) receptor antagonist bicuculline further reduced the remaining responses. Electrical stimulation of the RdVII evoked postsynaptic currents (PSCs) in all 19 masseter motoneurons tested in postnatal day (P)1-4 rats, and application of CNQX and the NMDA receptor antagonist (+/-)-3(2-carboxypiperazin-4-yl)propyl-1-phosphonic acid (CPP) reduced the PSC amplitudes by more than 50%. In the presence of CNQX and CPP, the GABA(A) receptor antagonist SR95531 further reduced PSC amplitude, and addition of strychnine abolished the remaining PSCs. Photostimulation of the RdVII with caged glutamate also evoked PSCs in masseter motoneurons of P3-4 rats. In P8-11 rats, electrical stimulation of the RdVII also evoked PSCs in all 14 masseter motoneurons tested, and the effects of the antagonists on the PSCs were similar to those in P1-4 rats. On the other hand, RdVII stimulation evoked PSCs in only three of 16 digastric motoneurons tested. These results suggest that both neonatal and juvenile jaw-closing motoneurons receive strong synaptic inputs from the RdVII through activation of glutamate, glycine and GABA(A) receptors, whereas inputs from the RdVII to jaw-opening motoneurons seem to be weak.


Assuntos
Neurônios Motores/fisiologia , Formação Reticular/fisiologia , Transmissão Sináptica , Núcleos do Trigêmeo/fisiologia , Animais , Animais Recém-Nascidos , Estimulação Elétrica , Técnicas In Vitro , Músculo Masseter/crescimento & desenvolvimento , Músculo Masseter/inervação , Técnicas de Patch-Clamp , Estimulação Luminosa , Ratos , Ratos Wistar , Receptores de GABA-A/fisiologia , Receptores de Glutamato/fisiologia , Receptores de Glicina/fisiologia , Formação Reticular/crescimento & desenvolvimento , Potenciais Sinápticos , Núcleos do Trigêmeo/citologia , Núcleos do Trigêmeo/crescimento & desenvolvimento
6.
J Investig Allergol Clin Immunol ; 18(3): 174-80, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18564628

RESUMO

BACKGROUND: Interleukin (IL) 13 is a key cytokine in asthma, regulating fibrosis, airway remodeling, induction of immunoglobulin E synthesis by B cells, bronchial hyperresponsiveness, and mucus production. IL-13 signals through the type II IL-4 receptor (IL-4R), which is composed of the IL-4Ralpha and the IL-13Ralpha1 chains. Another IL-13 binding chain, IL-13Ralpha2, binds IL-13 with high affinity but has no known signaling capability and is thought to serve as a decoy receptor providing tight regulation of IL-13 responses. METHODS: In this study, we investigated the cellular localization of IL-13Ralpha2 in human primary bronchial epithelial cells and fibroblasts using flow cytometry and confocal microscopy, as well as the in vivo expression of IL-13Ralpha2 in the human bronchial mucosa by means of immunohistochemistry. RESULTS: IL-13Ralpha2 is predominantly an intracellular rather than a membrane-bound molecule in both human primary bronchial epithelial cells and fibroblasts and displays a diffuse granular cytoplasmic distribution in both cell types. IL-13Ralpha2 protein is expressed in vivo in the human bronchial mucosa with its expression being higher in bronchial epithelial cells than bronchial fibroblasts both in vivo and in vitro. CONCLUSIONS: IL-13Ralpha2 is expressed by both human primary bronchial epithelial cells and fibroblasts as an intracellular protein with a diffuse cytoplasmic distribution. In vivo, IL-13Ralpha2 is expressed in the human airway mucosa mainly by bronchial epithelial cells.


Assuntos
Brônquios/imunologia , Células Epiteliais/imunologia , Fibroblastos/imunologia , Subunidade alfa2 de Receptor de Interleucina-13/metabolismo , Mucosa Respiratória/imunologia , Adulto , Brônquios/citologia , Linhagem Celular , Células Cultivadas , Citoplasma/imunologia , Células Epiteliais/citologia , Fibroblastos/citologia , Humanos , Mucosa Respiratória/citologia , Células U937
7.
Kyobu Geka ; 59(12): 1082-5, 2006 Nov.
Artigo em Japonês | MEDLINE | ID: mdl-17094545

RESUMO

A 74-year-old man who had previously undergone prosthetic graft replacement of the total aortic arch using the elephant trunk technique and of the abdominal aorta was admitted to our hospital for surgical treatment of descending aortic aneurysm. Computed tomography (CT) on admission revealed descending aortic aneurysm of 6.5 cm in diameter, and the previously placed prosthetic graft was detected in the aneurysm. Surgery for the descending aorta was performed under femoro-femoral partial bypass. During the operation, a balloon occlusion catheter introduced through the right brachial artery into the 'elephant trunk' graft was inflated before the aneurysm was opened, then the previously placed prosthetic graft was cross-clamped and the descending aorta was replaced with a new prosthetic graft with usual fashion. The postoperative course was uneventful.


Assuntos
Aorta Torácica/cirurgia , Aneurisma da Aorta Torácica/terapia , Oclusão com Balão , Implante de Prótese Vascular , Idoso , Anastomose Cirúrgica , Aneurisma da Aorta Torácica/diagnóstico por imagem , Aneurisma da Aorta Torácica/cirurgia , Humanos , Masculino , Reoperação , Tomografia Computadorizada por Raios X , Procedimentos Cirúrgicos Vasculares/métodos
8.
J Theor Biol ; 236(4): 366-75, 2005 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-15899502

RESUMO

The vegetative hormone Auxin is involved in vascular tissues formation throughout the plant. Trans-membrane carrier proteins transporting auxin from cell to cell and distributed asymmetrically around each cell give to auxin a polarized movement in tissues, creating streams of auxin that presume future vascular bundles. According to the canalization hypothesis, auxin transport ability of cells is thought to increase with auxin flux, resulting in the self-enhancement of this flux along auxin paths. In this study we evaluate a series of models based on canalization hypothesis using carrier proteins, under different assumptions concerning auxin flux formation and carrier protein dynamics. Simulations are run on a hexagonal lattice with uniform auxin production. A single cell located in the margin of the lattice indicates the petiole, and acts as an auxin sink. The main results are: (1) We obtain branching auxin distribution patterns. (2) The type of self-enhancement described by the functional form of the carrier proteins regulation responding to the auxin flux intensity in different parts of a cell, has a strong effect on the possibility of generating the branching patterns. For response functions with acceleration in the increase of carrier protein numbers compared to the auxin flux, branching patterns are likely to be generated. For linear or decelerating response functions, no branching patterns are formed. (3) When branching patterns are formed, auxin distribution greatly differs between the case in which the number of carrier proteins in different parts of a cell are regulated independently, and the case in which different parts of a cell compete for a limited number of carrier proteins. In the former case, the auxin level is lower in veins than in the surrounding tissue, while in the latter, the auxin is present in greater abundance in veins. These results suggest that canalization is a good candidate for describing plant vein pattern formation.


Assuntos
Ácidos Indolacéticos/metabolismo , Folhas de Planta/anatomia & histologia , Fenômenos Fisiológicos Vegetais , Transporte Biológico , Proteínas de Transporte/metabolismo , Modelos Biológicos , Folhas de Planta/metabolismo , Transpiração Vegetal
10.
Acta Neuropathol ; 105(6): 610-4, 2003 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-12669238

RESUMO

We report a Japanese autopsy case of progressive supranuclear palsy (PSP). The male patient was 74 years old at the time of death. At age 64, he developed non-fluent aphasia that progressed slowly over 8 years, eventually associated with behavioral abnormality, postural instability, and dysphagia at 2 years prior to his death. Magnetic resonance imaging of the brain at age 73 demonstrated marked atrophy of the frontal lobes, particularly on the left side. Neuropathological examination revealed the typical pathology of PSP: loss of neurons, gliosis, occurrence of neurofibrillary tangles, oligodendroglial coiled bodies, and tuft-shaped astrocytes in the frontal cortex, associated with argyrophilic threads in the underlying white matter, in the basal ganglia, including the thalamus, globus pallidus, and subthalamic nucleus, and in the brainstem nuclei, including the substantia nigra, pontine nucleus, and inferior olivary nucleus. No astrocytic plaques or ballooned neurons were observed. Protein analysis revealed accumulation of hyperphosphorylated tau of 68 and 64 kDa consisting of the four repeat tau isoforms. We conclude that the present case represented PSP with an 8-year history of primary progressive aphasia (PPA). Although focal cortical symptoms in PSP are rare or absent, we should keep in mind the possibility of atypical PSP in which cortical pathology is predominant, particularly in the frontal lobe, and could result in PPA.


Assuntos
Afasia Primária Progressiva/complicações , Paralisia Supranuclear Progressiva/complicações , Idoso , Envelhecimento/metabolismo , Envelhecimento/patologia , Afasia Primária Progressiva/patologia , Autopsia , Western Blotting , Encéfalo/anatomia & histologia , Encéfalo/metabolismo , Progressão da Doença , Humanos , Imuno-Histoquímica , Imageamento por Ressonância Magnética , Masculino , Emaranhados Neurofibrilares/metabolismo , Emaranhados Neurofibrilares/patologia , Isoformas de Proteínas/imunologia , Isoformas de Proteínas/metabolismo , Paralisia Supranuclear Progressiva/patologia , Proteínas tau/metabolismo
11.
Eur J Pharmacol ; 430(1): 123-33, 2001 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-11698072

RESUMO

We investigated the effects of F-1322 (N-[2-[4-(benzhydryloxy)piperidino]ethyl]-3-hydroxy-5-(3-pyridylmethoxy)-2-naphthamide), a new compound that inhibits both thromboxane A2 synthetase and 5-lipoxygenase and that functions as a histamine antagonist, on the Ascaris antigen-induced late asthmatic response and pulmonary eosinophilia in guinea pigs. Oral administration of F-1322 (10-100 mg/kg) inhibited the antigen-induced late asthmatic response in a dose-dependent manner. Histological analysis revealed that F-1322 prevented the accumulation of eosinophils in the airways and this was paralleled by a decrease in the number of eosinophils and lymphocytes recovered in bronchoalveolar lavage fluid. F-1322 (0.1-10 microM) inhibited eotaxin-induced chemotaxis and actin polymerization of eosinophils in vitro in a concentration-dependent manner, while oral administration of F-1322 dose-dependently suppressed the migration of eosinophils into the airways in vivo in response to infusion of interleukin 5 and eotaxin in combination. F-1322 may, thus, improve the late asthmatic response in this model, in part, by preventing the accumulation of eosinophils in the airways. The pharmacological profile of F-1322 indicates that this drug is likely to be useful in the treatment of allergic diseases such as asthma.


Assuntos
Antiasmáticos/farmacologia , Asma/tratamento farmacológico , Eosinofilia/imunologia , Pneumopatias/imunologia , Naftalenos/farmacologia , Resistência das Vias Respiratórias/efeitos dos fármacos , Alérgenos , Animais , Antígenos de Helmintos , Asma/etiologia , Asma/imunologia , Líquido da Lavagem Broncoalveolar/citologia , Movimento Celular/efeitos dos fármacos , Células Cultivadas , Quimiocina CCL11 , Quimiocinas CC/administração & dosagem , Quimiotaxia , Modelos Animais de Doenças , Eosinófilos/efeitos dos fármacos , Eosinófilos/imunologia , Cobaias , Interleucina-5/administração & dosagem , Fatores de Tempo
12.
J Clin Neurophysiol ; 18(2): 185-90, 2001 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-11435811

RESUMO

The authors studied the origin of the scalp P13-like potential in median somatosensory evoked potentials, which have been reported to be preserved in patients with cervicomedullary lesions or in brain death. There were five patients with high to middle cervical lesions (C2/3 or C3/4 level). Small P13-like potentials after P11 were identified for all patients with a noncephalic reference but not with an ear reference. Their onset latencies were slightly earlier than the expected latency of the true P13/14 onset. In two patients, delayed true P13/14s followed by N18s were identified with both noncephalic and ear references. The authors argue that the P13-like potential observed in these patients is a different entity from scalp P13 in normal subjects. Because the C3/4 vertebral level corresponds to the C5 cord level, the origin of the P13-like potential must be below C5, contradicting the previous opinion that it is generated at the cervicomedullary junction or at the high cervical dorsal column. The authors named this potential lower cervical P13 (or lcP13), and present an opinion that it is generated by the beginning of the second spinal ascending volley, which has been described by direct-recording studies in humans.


Assuntos
Potenciais Somatossensoriais Evocados , Esclerose Múltipla/fisiopatologia , Doenças da Medula Espinal/fisiopatologia , Medula Espinal/fisiopatologia , Osteofitose Vertebral/fisiopatologia , Adulto , Idoso , Potenciais Somatossensoriais Evocados/fisiologia , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Nervo Mediano , Pessoa de Meia-Idade , Esclerose Múltipla/complicações , Esclerose Múltipla/diagnóstico , Pescoço/patologia , Tempo de Reação , Medula Espinal/patologia , Doenças da Medula Espinal/complicações , Doenças da Medula Espinal/diagnóstico , Osteofitose Vertebral/complicações , Osteofitose Vertebral/diagnóstico
13.
Clin Neurophysiol ; 112(2): 300-3, 2001 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11165533

RESUMO

OBJECTIVE: To compare voluntary single fiber electromyography (v-SFEMG) and repetitive nerve stimulation (RNS) at the same extensor digitorum communis (EDC) muscle in myasthenia gravis (MG). METHODS: We examined v-SFEMG and RNS successively on the same day in the same EDC muscle. We studied 45 examinations of both v-SFEMG and RNS in 29 patients suffering from MG, together with examinations of RNS in 30 control subjects. RESULTS: Forty-one of 45 (91%) v-SFEMGs showed abnormal results, whereas only 18/45 (40%) RNSs showed an abnormal decrement. The percentage of decrement showed similar correlations with 3 v-SFEMG parameters: percentage of abnormal pairs, percentage of blocking pairs, and the mean MCD value. Examinations showing a significant decrement in RNS had at least 60%, and usually no less than 90%, abnormal pairs, and 10-80% blocking pairs. Some muscles without a decrement had up to 50% blocking pairs. CONCLUSIONS: These results suggest that the blocking phenomenon observed in v-SFEMG is not a direct counterpart of the decrement in RNS. This must be partly because fibers contributing to the decrement are continuously blocked during voluntary contraction, and partly, because smaller motor units explored by v-SFEMG are probably more abnormal in MG than larger motor units mainly contributing to a decrement. Both factors make v-SFEMG much more sensitive than RNS.


Assuntos
Eletromiografia , Dedos , Fibras Musculares Esqueléticas/fisiologia , Músculo Esquelético/inervação , Músculo Esquelético/fisiopatologia , Miastenia Gravis/fisiopatologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Estimulação Elétrica/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Sistema Nervoso/fisiopatologia , Valores de Referência , Transmissão Sináptica
14.
Rinsho Shinkeigaku ; 41(7): 387-9, 2001 Jul.
Artigo em Japonês | MEDLINE | ID: mdl-11808347

RESUMO

A 50-year-old man had been well until three months earlier, when he felt general fatigue, and cutaneous rash with itching. Thereafter a general muscular weakness developed and the patient could not walk for a month. Four weeks before referral to our hospital, he had high fever and could not role over in the bed. On admission, the patient was able to walk. He had no skin rash. Neurologically, he showed mild weakness in proximal muscles. Hematologic examination showed mild eosinophilia and serum creatine kinase was mildly elevated. Needle electromyogram revealed a diffuse myogenic pattern in extremities. Eosinophilic myositis was diagnosed by a biopsy of the left calf muscle showing mild infiltration of eosinophilis which was identified using antibodies against eosinophilic granule protein.


Assuntos
Autoanticorpos/imunologia , Proteínas Sanguíneas/imunologia , Eosinofilia/complicações , Miosite/diagnóstico , Ribonucleases , Proteínas Granulares de Eosinófilos , Humanos , Imuno-Histoquímica , Masculino , Pessoa de Meia-Idade , Músculo Esquelético/patologia , Miosite/patologia
16.
Plant Sci ; 158(1-2): 139-145, 2000 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-10996253

RESUMO

Carnation petals exhibit autocatalytic ethylene production and wilting during senescence. The autocatalytic ethylene production is caused by the expression of 1-aminocyclopropane-1-carboxylate (ACC) synthase and ACC oxidase genes, whereas the wilting of petals is related to the expression of the cysteine proteinase (CPase) gene. So far, it has been believed that the ethylene production and wilting are regulated in concert in senescing carnation petals, since the two events occurred closely in parallel with time. In the present study, we investigated the expression of these genes in petals of a transgenic carnation harboring a sense ACC oxidase transgene and in petals of carnation flowers treated with 1,1-dimethyl-4-(phenylsulfonyl)semicarbazide (DPSS). In petals of the transgenic carnation flowers, treatment with exogenous ethylene caused accumulation of the transcript for CPase and in-rolling (wilting), whereas it caused no or little accumulation of the transcripts for ACC oxidase and ACC synthase and negligible ethylene production. In petals of the flowers treated with DPSS, the transcripts for ACC synthase and ACC oxidase were accumulated, but no significant change in the level of the transcript for CPase was observed. These results suggest that the expression of ACC synthase and ACC oxidase genes, which leads to ethylene production, is differentially regulated from the expression of CPase, which leads to wilting, in carnation petals.

17.
Biochem Biophys Res Commun ; 273(3): 1063-8, 2000 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-10891372

RESUMO

The gene of mammalian endonuclease III homologs (NTHL1/Nthl1), a DNA glycosylase/AP lyase involved in base excision repair, lies immediately adjacent to one of the tuberous sclerosis disease-determining genes, TSC2/Tsc2, in a head-to-head orientation. To clarify the regulation of these divergent genes, we studied the promoter activities of these transcription units by luciferase assay using HeLa cells. We found that the short spacer sequence of 63 base pairs (bp) between the mouse Nthl1 and Tsc2 genes shows bidirectional promoter activity essential for the transcription of both genes. The 63-bp sequence is well conserved among several mammalian species and contains two Ets-transcription factor binding sites (EBSs) in opposite directions. An Ets-family protein in the HeLa nuclear extract specifically bound to either EBSs. Mutation of the core motif of the EBS demonstrated that EBS positively regulates transcription of both mNthl1 and mTsc2 genes. These EBSs had an additive effect on transcription, and each EBS functioned equally in both directions.


Assuntos
Desoxirribonuclease (Dímero de Pirimidina) , Endodesoxirribonucleases/genética , Proteínas de Escherichia coli , Regiões Promotoras Genéticas , Proteínas Repressoras/genética , Animais , Sequência de Bases , DNA , Primers do DNA , Regulação da Expressão Gênica , Células HeLa , Humanos , Camundongos , Dados de Sequência Molecular , Proteína 2 do Complexo Esclerose Tuberosa , Proteínas Supressoras de Tumor
18.
Biomaterials ; 21(14): 1471-81, 2000 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10872776

RESUMO

Platelet adhesion and spreading is suppressed when a poly(2-methoxyethylacrylate) (PMEA) surface is used, compared with other polymer surfaces. To clarify the reason for this suppression, the relationship among the amount of the plasma protein adsorbed onto PMEA, its secondary structure and platelet adhesion was investigated. Poly(2-hydroxyethylmethacrylate) (PHEMA) and polyacrylate analogous were used as references. The amount of protein adsorbed onto PMEA was very low and similar to that absorbed onto PHEMA. Circular dichroism (CD) spectroscopy was applied to examine changes in the secondary structure of the proteins after adsorption onto the polymer surface. The conformation of the proteins adsorbed onto PHEMA changed considerably, but that of proteins adsorbed onto PMEA differed only a little from the native one. These results suggest that low platelet adhesion and spreading are closely related to the low degree of the denaturation of the protein adsorbed onto PMEA. PMEA could be developed as a promising material to produce a useful blood-contacting surface for medical devices.


Assuntos
Acrilatos/química , Acrilatos/metabolismo , Materiais Biocompatíveis , Proteínas Sanguíneas/metabolismo , Adesividade Plaquetária , Polímeros/química , Polímeros/metabolismo , Adsorção , Materiais Biocompatíveis/química , Plaquetas/fisiologia , Plaquetas/ultraestrutura , Proteínas Sanguíneas/química , Dicroísmo Circular , Humanos , Técnicas In Vitro , Cinética , Microscopia Eletrônica de Varredura , Poli-Hidroxietil Metacrilato/química , Ligação Proteica , Estrutura Secundária de Proteína , Soroalbumina Bovina/química , Soroalbumina Bovina/metabolismo
19.
Enzyme Microb Technol ; 26(8): 621-629, 2000 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-10793210

RESUMO

Anthocyanin production by strawberry cells depends not only on light intensity but also on the light/dark cycle operation with hour- or second-scale periods. These findings are useful for designing and operating photobioreactors for enhanced anthocyanin production. Intermittent illumination with a second-scale period produces the same amount of anthocyanin as continuous light, suggesting that the light intensity distribution within a photobioreactor does not cause suppressed production. In the hour-scale cycle, continuous light operation enhanced anthocyanin production more than the light/dark cycle process.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...