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1.
Neuroendocrinology ; 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31940636

RESUMO

PURPOSE: To evaluate whether the European Neuroendocrine Tumor Society (ENETS) system or the 8th American Joint Committee on Cancer (AJCC) staging manual are suitable for gastric neuroendocrine carcinomas and/or mixed adenoneuroendocrine carcinomas (G-NECs/MANECs). METHODS: Patients in the a multicentric series with G-NEC/MANEC who underwent curative-intent surgical resection for a primary tumor were included. An optimal staging system was proposed base on analysis of the T and N status and validated by the SEER database. RESULTS: Compared with the ENETS system, the survival curves of the T category and N category in the 8th AJCC system were better separated and distributed in a more balanced way, but the survival curves of T2 vs T3, N0 vs N1, and N3a vs N3b overlapped. For the T category, the 8th AJCC T category was modified by combining T2 and T3, which was consistent with the T category in the 6th AJCC manual for GC. For the N category, the optimal cut-off values of metastatic lymph nodes using X-tile were also similar to those of the N category in the 6th AJCC system. The Kaplan-Meier plots of the 6th AJCC system showed statistically significant differences between individual substages. Compared with the other two classifications, the 6th AJCC system also showed superior prognostic stratification. Similar results were obtained in both multicentric and SEER validation sets. CONCLUSIONS: Compared to the 8th AJCC and ENETS systems, the 6th AJCC staging system for GC is more suitable for G-NEC/MANEC and can be adopted in clinical practice.

2.
ACS Omega ; 4(23): 20275-20284, 2019 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-31815230

RESUMO

Polyphosphazene microspheres were fabricated by ultrasonic-assisted precipitation polymerization using 4,4'-(hexafluoroisopropylidene)diphenol, 4,4'-sulfonyldiphenol, 4,4-(9-fluorenylidene)diphenol, and phenolphthalein to obtain poly[4,4'-(hexafluoroisopropylidene)diphenol]phosphazene (PZAF), poly(4,4'- sulfonyldiphenol)phosphazene (PZS), poly[4,4'-(9-fluorenylidene)diphenol]phosphazene, and poly(phenolphthalein)phosphazene (PZPT) and were incorporated into polybenzoxazines (PBa) to obtain corresponding PZAF/PBa, PZS/PBa, fluorenyl polyphosphazene (PZFP)/PBa, and PZPT/PBa composites. Addition of 5 wt % of PZAF, PZS, PZFP, and PZPT microspheres improved the thermal stability and fire retardancy of PBa resin significantly. Notably, addition of PBa with 5% PZAF led to a 62.5% decrease in the peak heat release rate and 49.3% reduction in total heat release. The role of microspheres in the gas-phase flame-retardancy mechanism in the PBa matrix was studied. Dynamic mechanical analysis results demonstrated that the T g of PBa flame-retardant composites was still around 210 °C compared to 221 °C of pure PBa. Hence, the synthesized PBa composites had potential applications as high flame-retardancy materials.

3.
PLoS One ; 14(9): e0221333, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31490952

RESUMO

To balance the supply and demand in China's beef market, beef consumption must be scientifically and effectively forecasted. Beef consumption is affected by many factors and is characterized by gray uncertainty. Therefore, gray theory can be used to forecast the beef consumption, In this paper, the structural defects and unreasonable parameter design of the traditional gray model are analyzed. Then, a new gray model termed, EGM(1,1,r), is built, and the modeling conditions and error checking methods of EGM(1,1,r) are studied. Then, EGM(1,1,r) is used to simulate and forecast China's beef consumption. The results show that both the simulation and prediction precisions of the new model are better than those of other gray models. Finally, the new model is used to forecast China's beef consumption for the period from 2019-2025. The findings will serve as an important reference for the Chinese government in formulating policies to ensure the balance between the supply and demand for Chinese beef.

4.
J Cancer Res Ther ; 14(Supplement): S79-S84, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29578154

RESUMO

Aim: Patients aged 65 years and older are often underrepresented in clinical trials of metastatic colorectal cancer (mCRC) and probably undertreated in clinical practice. We performed a meta-analysis of randomized controlled trials (RCTs) to assess the efficacy of molecular targeted agents (MTAs) in this population. Materials and Methods: A comprehensive literature search for studies published up to December 2014 was performed. The endpoints were overall survival (OS) and progression-free survival (PFS). The pooled hazard ratio (HR) and 95% confidence intervals (CIs) were calculated employing fixed- or random-effects models depending on the heterogeneity of the included trials. Results: Eleven RCTs involving 8,488 patients were ultimately identified. The pooled analysis demonstrated that the use of MTAs in elderly patients with mCRC significantly improve OS (HR 0.84, 95% CI: 0.76-0.92, P < 0.001) and PFS (HR 0.78, 95% CI: 0.64-0.96, P = 0.017) when compared to MTAs-free therapies. Similar results of OS were observed in subgroup analysis according to treatment line, therapy regimes, and approval status of MTAs. No publication bias was detected by Begg's and Egger's tests. Conclusions: The introduction of MTAs to therapies offered a survival benefit in elderly patients with mCRC. Further studies aimed at this specific patient population were still needed to watchfully monitor potential treatment-related toxicities to optimize the use of these drugs.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/patologia , Terapia de Alvo Molecular , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Neoplasias Colorretais/mortalidade , Humanos , Terapia de Alvo Molecular/efeitos adversos , Terapia de Alvo Molecular/métodos , Metástase Neoplásica , Estadiamento de Neoplasias , Modelos de Riscos Proporcionais , Viés de Publicação , Ensaios Clínicos Controlados Aleatórios como Assunto , Resultado do Tratamento
5.
Int J Mol Med ; 41(4): 2213-2224, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29393354

RESUMO

The present study investigated the effects of dual specificity phosphatase 1 (DUSP1) gene silencing using lentiviral vector-mediated small interfering (si)RNA on the release of proinflammatory cytokines through the regulation of the mitogen­activated protein kinase (MAPK) signaling pathway in mice with acute pancreatitis (AP). Two siRNA­DUSP1 sequences and one scramble siRNA sequence were designed, and the expression of DUSP1 was detected using western blot analysis to screen for the one with a higher interference rate. An AP mouse model was established, and KM mice were assigned to either a control, siRNA, AP, AP+PD98059, AP+scramble, AP+siRNA or AP+PD98059+siRNA group. The expression of proinflammatory cytokines, including tumor necrosis factor (TNF)­α, interleukin (IL)­1ß and IL­6, high mobility group box 1 (HMGB1), and S100A12 in serum samples were detected using an enzyme­linked immunosorbent assay at 12, 24 and 48 h post­modeling. The serum amylase levels were also detected. The expression levels of DUSP1, TNF­α, IL­1ß, IL­6, HMGB1, S100A12, phosphorylated (p­) extracellular signal­regulated kinase (ERK), p­c­Jun N­terminal kinase (JNK), p­p38, ERK, JNK and p38 in pancreatic, liver, kidney and lung tissues were detected using reverse transcription­quantitative polymerase chain reaction and western blot analysis. Compared with the control group, the siRNA group demonstrated marginally upregulated serum amylase, lipase, urinary trypsinogen­2, and proinflammatory cytokines, HMGB1 and S100A12 in serum and tissues, with no statistically significant difference, elevated expression levels of p­ERK, p­JNK and p­p38, and decreased expression of DUSP1. The other five groups demonstrated increased expression levels of TNF­α, IL­1ß, IL­6, HMGB1, S100A12, amylase, lipase and urinary trypsinogen­2 in serum, and increased expression levels of DUSP1, TNF­α, IL­1ß, IL­6, HMGB1, S100A12, p­ERK, p­JNK and p­p38 in tissues. Compared with the AP group, the AP+PD98059+siRNA group had decreased expression of DUSP1 in tissues, whereas the AP+PD98059 group had decreased serum expression levels of TNF­α, IL­1ß, IL­6, HMGB1, S100A12 and amylase, lipase and urinary trypsinogen­2. The expression levels of TNF­α, IL­1ß, IL­6, HMGB1, S100A12, p­ERK, p­JNK, p­p38 in tissues, and edema of pancreatic tissue were alleviated, whereas the opposite results were observed in the AP+siRNA group with the decreased expression of DUSP1. The results suggested that DUSP1 gene silencing promoted the release of proinflammatory cytokines through activation of the MAPK signaling pathway in mice with AP.


Assuntos
Citocinas/imunologia , Fosfatase 1 de Especificidade Dupla/imunologia , Sistema de Sinalização das MAP Quinases , Pancreatite/imunologia , Doença Aguda , Animais , Citocinas/sangue , Modelos Animais de Doenças , Fosfatase 1 de Especificidade Dupla/genética , Células HEK293 , Humanos , Lentivirus/genética , Masculino , Camundongos , Pâncreas/imunologia , Pâncreas/patologia , Pancreatite/sangue , Pancreatite/genética , Pancreatite/patologia , Interferência de RNA , RNA Interferente Pequeno/genética
6.
Artigo em Inglês | MEDLINE | ID: mdl-29295517

RESUMO

With the rapid development of the Yangtze River economic belt, the amount of waste-sewage water discharged into the Yangtze River basin increases sharply year by year, which has impeded the sustainable development of the Yangtze River basin. The water security along the Yangtze River basin is very important for China, It is something aboutwater security of roughly one-third of China's population and the sustainable development of the 19 provinces, municipalities and autonomous regions among the Yangtze River basin. Therefore, a scientific prediction of the amount of waste-sewage water discharged into Yangtze River basin has a positive significance on sustainable development of industry belt along with Yangtze River basin. This paper builds the fractional DWSGM(1,1)(DWSGM(1,1) model is short for Discharge amount of Waste Sewage Grey Model for one order equation and one variable) model based on the fractional accumulating generation operator and fractional reducing operator, and calculates the optimal order of "r" by using particle swarm optimization(PSO)algorithm for solving the minimum average relative simulation error. Meanwhile, the simulation performance of DWSGM(1,1)model with the optimal fractional order is tested by comparing the simulation results of grey prediction models with different orders. Finally, the optimal fractional order DWSGM(1,1)grey model is applied to predict the amount of waste-sewage water discharged into the Yangtze River basin, and corresponding countermeasures and suggestions are put forward through analyzing and comparing the prediction results. This paper has positive significance on enriching the fractional order modeling method of the grey system.


Assuntos
Modelos Teóricos , Rios , Águas Residuárias , China , Cidades , Conservação dos Recursos Naturais , Previsões
7.
J Chemother ; 28(4): 321-7, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26239366

RESUMO

AIM: Patients aged 65 years and older are often under-represented in clinical trials of metastatic colorectal cancer (mCRC) and probably undertreated in clinical practice. We performed a meta-analysis of randomized controlled trials to assess the efficacy of molecular targetted agents (MTAs) in this population. METHODS: A comprehensive literature search for studies published up to December 2014 was performed. The endpoints were overall survival (OS) and progression-free survival (PFS). The pooled hazard ratio (HR) and 95% confidence intervals (CI) were calculated employing fixed- or random-effects models depending on the heterogeneity of the included trials. RESULTS: Eleven randomized controlled trials involved 8,488 patients were ultimately identified. The pooled analysis demonstrated that the use of MTAs in elderly patients with mCRC significantly improved OS (HR 0.84, 95% CI: 0.76-0.92, p < 0.001) and PFS (HR 0.78, 95% CI: 0.64-0.96, p = 0.017) when compared to MTAs-free therapies. Similar results of OS were observed in sub-group analysis according to treatment line and regimes. No publication bias was detected by Begg's and Egger's tests. CONCLUSIONS: The introduction of MTAs to therapies offers a survival benefit in elderly patients with mCRC. Further studies aimed at this specific patient population are still needed to monitor potential treatment-related toxicities to optimize the use of these drugs.


Assuntos
Neoplasias Colorretais/tratamento farmacológico , Terapia de Alvo Molecular , Fatores Etários , Idoso , Neoplasias Colorretais/mortalidade , Neoplasias Colorretais/patologia , Intervalo Livre de Doença , Humanos , Metástase Neoplásica , Ensaios Clínicos Controlados Aleatórios como Assunto , Análise de Sobrevida
8.
J Transl Med ; 13: 388, 2015 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-26699707

RESUMO

PURPOSE: There is limited information on the prevalence of vitamin D deficiency among patients diagnosed with hip fracture in the Chinese Han population. Therefore, the aim of this study was to assess the effects of change in the serum levels of 25-hydroxyvitamin D [25(OH) D] and intact parathyroid hormone (iPTH) among postmenopausal women in North China with confirmed hip fracture. METHODS: This study was done from May 1, 2012 to April 30, 2014. Three hundred and forty-nine postmenopausal women who were diagnosed with first-ever hip fracture and 349 matched controls without fracture were used for this study. The 25(OH) D, iPTH, alkaline phosphatase, calcium, and phosphorus levels were measured in fasting venous blood samples collected from the subjects. A predesigned questionnaire was used to collect information on covariates for multivariate analyses to evaluate the hypothesized relationship between vitamin D deficiency and fracture risk. RESULTS: The serum 25(OH) D levels were found to be significantly (P < 0.0001) lower in hip fracture patients than in the controls [37.0 (interquartile range [IQR] 28.0-48.0) nmol/L vs. 41.3 (IQR 32.0-54.5) nmol/L; P < 0.0001], and the iPTH levels were significantly higher in the former group [10.2 (IQR 6.3-14.9) pmol/L vs. 5.8 (IQR 4.1-6.6) pmol/L; P < 0.0001]. Further, a 25(OH) D level ≤50 nmol/L was found to independently indicate the occurrence of hip fracture [odds ratio (OR), 3.023; 95 % confidence interval (CI) 2.154-4.298], as well as hip fracture with concomitant upper limb fracture (OR 4.473; 95 % CI 2.984-10.532). Similarly, a serum iPTH level ≥6.8 pmol/L independently indicated the development of hip fracture (OR 2.498; 95 % CI 1.764-3.942), as well as hip fracture with concomitant upper limb fracture (OR 3.254; 95 % CI 1.998-7.984). CONCLUSIONS: Vitamin D insufficiency and secondary hyperparathyroidism were found to be common problems in the sample of postmenopausal women who had experienced hip fracture. Monitoring the alterations in the serum levels of 25(OH) D and iPTH could be applied clinically as independent risk factors for hip fracture.


Assuntos
Fraturas do Quadril/sangue , Pós-Menopausa , Vitamina D/análogos & derivados , Estudos de Casos e Controles , Feminino , Humanos , Pessoa de Meia-Idade , Vitamina D/sangue
9.
Trials ; 16: 183, 2015 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-25899566

RESUMO

BACKGROUND: Allergic rhinitis is a symptomatic allergic disease of the nose that affects 10 to 20% of the global population. Chinese otolaryngologists use one acupuncture needle to stimulate the sphenopalatine ganglion because of its potential advantages for treating moderate-severe persistent allergic rhinitis compared with traditional Chinese acupuncture (verum acupuncture); however, little evidence is available to support the wide clinical use thus far. Therefore, we propose a protocol for a parallel, multicenter, assessor-blinded, randomized controlled trial to evaluate sphenopalatine ganglion stimulation with one acupuncture needle compared to verum acupuncture for treatment of moderate-severe persistent allergic rhinitis. METHODS: In the trial, 96 patients previously diagnosed with moderate-severe persistent allergic rhinitis and meeting all inclusion criteria will be allocated to one of two equal therapeutic groups by using a computer-generated randomization list. The interventional group will receive sphenopalatine ganglion stimulation with one acupuncture needle for 4 weeks (once or twice weekly, total four to eight sessions); attending physicians will decide whether the second session is required in a week by examining signs and symptoms. The control group will receive individualized verum acupuncture for 4 weeks (twice weekly, total eight sessions). Follow-up evaluations will be performed 1 month later. The primary outcome measure is the change in the total nasal symptom score from the baseline to week 4. The secondary outcome measures include onset time and duration of effectiveness in every session, change in number of days with moderate-severe persistent allergic rhinitis from the baseline to week 8, change in total immunoglobulin E level and eosinophil count in venous blood from the baseline to week 4, change in Rhinoconjunctivitis Quality of Life Questionnaire score from the baseline to week 4, and clinical waiting time. DISCUSSION: The trial should provide evidence for the benefits of sphenopalatine ganglion stimulation with one acupuncture needle for treating moderate-severe persistent allergic rhinitis, including better change in total nasal symptom score, faster onset time, longer duration of effectiveness, and shorter treatment time. TRIAL REGISTRATION: Current Controlled Trials: ISRCTN21980724 (registered on 27 March 2014).


Assuntos
Gânglios Parassimpáticos/fisiopatologia , Rinite Alérgica/terapia , Terapia por Acupuntura/instrumentação , Terapia por Acupuntura/métodos , Biomarcadores/sangue , China , Protocolos Clínicos , Eosinófilos/imunologia , Humanos , Imunoglobulina E/sangue , Agulhas , Estudos Prospectivos , Qualidade de Vida , Projetos de Pesquisa , Rinite Alérgica/diagnóstico , Rinite Alérgica/imunologia , Rinite Alérgica/fisiopatologia , Índice de Gravidade de Doença , Inquéritos e Questionários , Fatores de Tempo , Resultado do Tratamento
10.
Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi ; 27(11): 1305-8, 2013 Nov.
Artigo em Chinês | MEDLINE | ID: mdl-24501887

RESUMO

OBJECTIVE: To investigate the operative method and effectiveness of repairing defects at medial malleolus in children with vascularized fibular head composite flap. METHODS: Between November 2008 and January 2011, 8 children with bone and soft tissue defects at the medial malleolus were treated. There were 5 boys and 3 girls, aged 2-9 years (mean, 4.6 years). Injuries were caused by machine twisting in 2 cases and by wheel twisting in 6 cases. Soft tissue defect area ranged from 3.5 cm x 3.0 cm to 7.0 cm x 4.5 cm; defect was total in all medial malleolus. The disease duration from injury to admission was 2-8 hours (mean, 4.5 hours). Defects were repaired with vascularized fibular head composite flap carrying the skin around the head of the fibula in 5 cases, and with vascularized fibular head composite flap and skin flap above the medial malleolus in 3 cases having too large defect (> 5 cm x 4 cm). The donor sites were repaired with direct suture in 2 cases and with skin graft in 6 cases. RESULTS: All 8 fibular head composite flaps and 3 skin flaps above the medial malleolus survived completely. Wounds healed by first intention; the skin grafts at donor sites survived in the other cases except 1 case having local necrosis, with healing of incision by first intention. The patients were followed up 10 months to 3 years (mean, 22 months). The color and elasticity of the flaps were good. All the children had equal leg length. Of 8 cases, 6 had no joint valgus; 2 cases had progressive ankle varus after 1 year of operation. The ankle flexion and extension function returned to normal in 5 cases, and was slightly limited in 3 cases; horizontal side, forward and backward movements had no difference compared with normal side. According to American Orthopaedic Foot and Ankle Society (AOFAS) ankle function evaluation criteria, the results were excellent in 5 cases, and good in 3 cases at 10 months after operation. X-ray film showed that the ankle hole gap development of both sides was similar; no premature closure of the epiphysis or bone bridge formation of the medial malleolus was observed in 6 cases, and bone bridge formed in 2 cases after 1 year of operation. CONCLUSION: The satisfactory short-term effectiveness can be obtained in repairing children medial malleolus and soft tissue defects by vascularized fibular head composite flap, and the reconstructed medial malleolus can develop with the growth of children. Long-term effectiveness still need more follow-up study.


Assuntos
Traumatismos do Tornozelo/cirurgia , Fíbula/cirurgia , Procedimentos Cirúrgicos Reconstrutivos/métodos , Lesões dos Tecidos Moles/cirurgia , Retalhos Cirúrgicos/irrigação sanguínea , Tendão do Calcâneo/lesões , Tendão do Calcâneo/cirurgia , Articulação do Tornozelo/cirurgia , Transplante Ósseo , Criança , Pré-Escolar , Feminino , Fíbula/irrigação sanguínea , Seguimentos , Humanos , Masculino , Complicações Pós-Operatórias/epidemiologia , Complicações Pós-Operatórias/etiologia , Amplitude de Movimento Articular , Resultado do Tratamento
11.
Biotechnol Prog ; 23(1): 278-85, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17269699

RESUMO

In this work, self-assembled poly(butadiene)-b-poly(ethylene oxide) (PB-PEO) polymersomes (polymer vesicles) and worm micelles were evaluated as paclitaxel carriers. Paclitaxel was successfully incorporated into PB-PEO polymersomes and worm micelles. The loading capacity of paclitaxel inside PB-PEO colloids ranged from 6.7% to 13.7% w/w, depending on the morphology of copolymer colloids and the molecular weight of diblock copolymer. Paclitaxel loaded OB4 (PB219-PEO121) polymersome formulations were colloidally stable for 4 months at 4 degrees C and exhibited slow steady release of paclitaxel over a 5 week period at 37 degrees C. Evaluation of the in vitro cytotoxicity of paclitaxel-polymersome formulations showed that the ability of paclitaxel-loaded polymersomes to inhibit proliferation of MCF-7 human breast cancer cells was less compared to paclitaxel alone. By increasing the concentration of paclitaxel in polymersomes from 0.02 to 0.2 mug/mL, paclitaxel-polymersome formulations showed comparable activity in inhibiting the growth of MCF-7 cells. Taken together, these results demonstrate that paclitaxel-polymersomes have desirable restrained release profile and exhibit long-term stability.


Assuntos
Neoplasias da Mama/patologia , Butadienos/química , Portadores de Fármacos/química , Elastômeros/química , Paclitaxel/administração & dosagem , Paclitaxel/química , Polietilenoglicóis/química , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Cristalização/métodos , Humanos , Teste de Materiais
12.
Biomaterials ; 26(17): 3759-69, 2005 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15621266

RESUMO

A new approach to enhance the circulation persistence of liposomes has been applied to develop liposome-encapsulated actin-hemoglobin (LEAcHb) dispersions as potential blood substitutes by introducing an actin matrix into the liposome aqueous core. Asymmetric flow field-flow fractionation coupled with multi-angle static light scattering was used to study the shape, size distribution, and encapsulation efficiency of liposome-encapsulated hemoglobin (LEHb) and LEAcHb dispersions. By polymerizing monomeric actin into filamentous actin inside the liposome aqueous core, LEAcHb particles transformed into a disk-like shape. We studied the effect of an encapsulated actin matrix on the size distribution, hemoglobin (Hb) encapsulation efficiency, oxygen affinity, and methemoglobin (MetHb) level of LEAcHb dispersions, and compared them with plain LEHb dispersions (without actin). LEHb, and LEAcHb dispersions extruded through 400 nm membranes were injected into rats and it was observed that LEAcHb dispersions with 1mg/mL of actin enhanced the circulatory half-life versus LEHb dispersions. The circulatory characteristics of empty PEGylated and non-PEGylated actin-containing liposomes (without Hb) were studied as controls for the LEHb and LEAcHb dispersions in this paper, which displayed maximum circulatory half-lives greater than 72 h. Taken together the results of this study supports our hypothesis that a lipid membrane supported by an underlying actin matrix will extend the circulatory half-life of LEHb dispersions.


Assuntos
Actinas/sangue , Actinas/química , Substitutos Sanguíneos/química , Substitutos Sanguíneos/metabolismo , Sistemas de Liberação de Medicamentos/métodos , Hemoglobinas/química , Hemoglobinas/metabolismo , Lipossomos/química , Animais , Substitutos Sanguíneos/administração & dosagem , Materiais Revestidos Biocompatíveis/administração & dosagem , Materiais Revestidos Biocompatíveis/química , Materiais Revestidos Biocompatíveis/metabolismo , Hemoglobinas/administração & dosagem , Masculino , Teste de Materiais , Taxa de Depuração Metabólica , Nanotubos/química , Nanotubos/ultraestrutura , Ratos , Ratos Sprague-Dawley
13.
Langmuir ; 20(19): 7917-25, 2004 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-15350053

RESUMO

Actin-containing liposomes were prepared via extrusion through 400 and 600 nm pore diameter membranes at different monomeric actin concentrations in low ionic strength buffer (G-buffer). After subjecting the liposome dispersions to high ionic strength polymerization buffer (F-buffer), topological changes in liposome structure were studied using atomic force microscopy (AFM). Paired dumbbell, horseshoelike, and disklike assemblies were observed for actin-containing liposomes extruded through 400 and 600 nm pore diameter membranes. The topology of actin-containing liposomes was found to be highly dependent on both liposome size and actin concentration. At 1 mg/mL actin, the actin-containing liposomes transformed into a disklike shape, whereas, at 5 mg/mL actin, the actin-containing liposomes retained a spherical shape. On the basis of these observations, we hypothesize that actin could either polymerize on the surface of the inner leaflet of the liposome membrane or polymerize in the aqueous core of the liposome. We explain the associated shape changes induced in actin-containing liposomes on the basis of the hypothesized mechanism of actin polymerization inside the liposomes. At higher actin concentrations (5 mg/mL), we observed membrane-induced actin self-assembly in G-buffer, which implies that G-actin is able to interact directly with lipid bilayers at sufficiently high concentrations.


Assuntos
Actinas/química , Lipossomos/química , Microscopia de Força Atômica/métodos , Tamanho da Partícula , Sensibilidade e Especificidade , Propriedades de Superfície
14.
Langmuir ; 20(11): 4629-39, 2004 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-15969175

RESUMO

Liposomes encapsulating monomeric actin (G-actin) were produced via extrusion through 400 and 600 nm pore diameter polycarbonate membranes in low ionic strength buffer (G-buffer). After actin-containing liposomes were subjected to high ionic strength polymerization buffer (F-buffer), morphological changes in the structure of actin-containing liposomes were studied using asymmetric flow field-flow fractionation (AFFF) coupled with multiangle static light scattering (MASLS). The general shape of these liposomes was initially determined by fitting three form factors, which describe the angular distribution of scattered light from a spherical thin shell, thin disk, and thin rod, to the experimentally measured light scattering spectra to regress the dimensions of the liposomes corresponding to the proposed geometry. Light scattering spectra that yielded a best fit to the thin disk model were analyzed further and fit to the ellipsoidal of revolution form factor to regress both the major and minor axis dimensions. The results of this analysis showed that actin-containing liposomes extruded through 400 and 600 nm pore diameter membranes in F-buffer, at a low actin concentration (0.1 mg/mL), assumed a spherical shape, which is also the case for plain liposomes (no actin present) in G-buffer and F-buffer. When the actin concentration was increased to 1 mg/mL, the polymerizing actin filaments stretched the initially spherical liposome into a disklike shape. However, when the actin concentration was further increased to 5 mg/mL, the liposomes reverted back to a spherical shape.


Assuntos
Actinas/análise , Actinas/farmacologia , Lipossomos/química , Tampões (Química) , Luz , Dinâmica não Linear , Espalhamento de Radiação , Análise Espectral
16.
Wei Sheng Wu Xue Bao ; 42(3): 359-63, 2002 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-12557380

RESUMO

When Candida tropicalis was cultivated in shakig-flask with the H2O2 addition, DCA (Dicarboxylic Acid, DCA) concentration was increased, especially at 2 mmol/L H2O2 concentration. The cytochrome P450 activity assays indicated that H2O2 addition significantly increased the activities of cytochrome P450 and DCA production positively correlated with the activities of cytochrome P450. The study on the cell growth demonstrated that the H2O2 addition inhibited the cell growth rate. However, the retarding effect was not irreversible since the cell growth rate could recover slowly to the original level after the H2O2 addition was halted. The mechanism of inducement on cytochrome P450 by H2O2 addition was also discussed in this article.


Assuntos
Candida tropicalis/enzimologia , Sistema Enzimático do Citocromo P-450/metabolismo , Ácidos Dicarboxílicos/síntese química , Peróxido de Hidrogênio/metabolismo , Aerobiose , Reatores Biológicos , Candida tropicalis/citologia , Indução Enzimática , Fermentação
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