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1.
Hu Li Za Zhi ; 68(5): 65-73, 2021 Oct.
Artigo em Zh | MEDLINE | ID: mdl-34549409

RESUMO

BACKGROUND & PROBLEMS: In response to a decrease in satisfaction to 69.3%, we resolved to optimize the process of conducting conscription physical examinations. After an investigatory panel conducted an analysis, the following problems were identified. Firstly, the poorly designed route lead to dense queues between exam stations. Secondly, the procedures for changing the dates of conscription physical examinations were cumbersome. Lastly, unexpected contacts between examinees and the patients in the hospital occurred from time to time, which increases the risk of cross infection. PURPOSE: This project was developed to improve the level of satisfaction in conscription physical examinations and increase the quality of medical services provided. RESOLUTION: After brainstorming and reviewing the related literature, we identified several actions to address and resolve the problems. We adopted non-crossing lines, divided the servicemen's cabins for inspection, simplified the information system process, relocated the physical examination venue, and planned education and training. RESULTS: Satisfaction with the examination process increased from 69.3% to 90.3%. CONCLUSIONS: A survey-based review of the conscription physical examination process should be conducted annually to ensure the procedures are as smooth as possible and to improve the quality of medical services provided.


Assuntos
Satisfação Pessoal , Exame Físico , Humanos , Inquéritos e Questionários
2.
Artif Organs ; 42(7): 705-713, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29602175

RESUMO

Anemia is a component of the pathological triangle in cardiorenal anemia syndrome and is a risk factor for mortality in acute respiratory distress syndrome. This study assessed the predictive value of anemia for outcomes in critically ill patients receiving extracorporeal membrane oxygenation (ECMO) support. This retrospective study analyzed patients who received ECMO support at the cardiovascular surgery intensive care unit in the study institute between July 2003 and March 2012. Patient data, such as demographic information, etiologies of ECMO implementation, clinical parameters, and in-hospital and 6-month mortality rates, were statistically analyzed. The overall in-hospital mortality rate among the enrolled 295 patients was 55.6%. Multivariate logistical regression analysis indicated that age, albumin levels, sequential organ failure assessment (SOFA) score, and hemoglobin (Hb) level on ECMO day 1 exhibited independent prognostic significance for predicting in-hospital mortality rate. The SOFA score exhibited the highest areas under the receiver operating characteristic curve value (0.812 ± 0.025). The Hb level on ECMO day 1 exhibited satisfactory calibration and discriminatory power. The cumulative 6-month survival rates differed significantly between patients with Hb levels less than and more than 8.85 g/dL (30.6 vs. 54.0%, respectively, P < 0.001). This study indicated that old age, low albumin levels, low Hb levels, and higher SOFA scores on ECMO day 1 increased the risk of mortality. The Hb level is a readily measurable parameter and with good predictive power for critical patients on ECMO.


Assuntos
Anemia/complicações , Estado Terminal , Oxigenação por Membrana Extracorpórea , Adulto , Fatores Etários , Idoso , Anemia/sangue , Feminino , Hemoglobinas/análise , Mortalidade Hospitalar , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Retrospectivos , Albumina Sérica Humana/análise , Taxa de Sobrevida
3.
Ticks Tick Borne Dis ; 15(1): 102284, 2024 01.
Artigo em Inglês | MEDLINE | ID: mdl-38016211

RESUMO

Newly recorded ticks and emerging tick-borne pathogens have recently been reported in subtropical and tropical East Asia. In this study, a total of 1,615 ticks (259 Haemaphysalis hystricis, 1334 Rhipicephalus microplus, 19 H. flava, and 3 R. haemaphysaloides) were collected by flagging from vegetation in Taiwan during 2019-2021. All 1,615 captured tick samples tested negative for SFTSV and Borrelia, but 12 of 356 tick samples tested positive for PCR amplification of a fragment of the 18S rRNA gene of Babesia spp., with an infection rate of 3.37 % (12/356) and a minimum infection rate of 0.74 % (12/1,615). Among the 12 detected Babesia spp., 11 were identified as Babesia bigemina in R. microplus, and the other one, detected in H. hystricis, was classified as an unnamed novel Babesia sp. Interestingly, the 18S rRNA sequence from the isolate detected in H. hystricis shared 98.79 % to 99.50 % identity with those of recent isolates from Japan, China and Nigeria. The exact origin of the Babesia species is not known, but the findings highlight the importance of international cooperation and the exchange of information on ticks and tick-borne pathogens. This represents a rare report of a Babesia sp. identified in H. hystricis, a tick species that has been proposed as a novel vector for some Babesia spp. This study supports H. hystricis as a possible vector of Babesia spp.


Assuntos
Babesia , Borrelia , Ixodidae , Rhipicephalus , Doenças Transmitidas por Carrapatos , Animais , Babesia/genética , Taiwan/epidemiologia
4.
Nutrients ; 14(4)2022 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-35215393

RESUMO

Underlying pathophysiological mechanisms drive excessive clustering of cardiometabolic risk factors, causing metabolic syndrome (MetS). MetS status may transform as adolescents transition to young adulthood. This study investigated the latent clustering structure and its stability for MetS during adolescence, and assessed the anthropometric and clinical metabolic determinants for MetS transformation. A community-based representative adolescent cohort (n = 1516) was evaluated for MetS using four diagnostic criteria, and was followed for 2.2 years to identify new-onset MetS. The clustering structure underlying cardiometabolic parameters was stable across adolescence; both comprised a fat-blood pressure (BP)-glucose three-factor structure (total variance explained: 68.8% and 69.7% at baseline and follow-up, respectively). Among adolescents with MetS-negative at baseline, 3.2-4.4% had incident MetS after 2.2 years. Among adolescents with MetS-positive at baseline, 52.0-61.9% experienced MetS remission, and 38.1-48.0% experienced MetS persistence. Increased systolic BP (SBP) was associated with a high MetS incidence risk, while decreased levels of SBP and glucose were associated with MetS remission. Compared with adolescents with a normal metabolic status at baseline, those with an initial abdominal obesity and increased triglycerides level had a 15.0- and 5.7-fold greater risk for persistent abnormality, respectively. Abdominal obesity and low high-density lipoprotein cholesterol are two abnormal MetS components that highly persist during adolescence, and are the intervention targets for reducing the future risk of cardiometabolic disorders.


Assuntos
Síndrome Metabólica , Adolescente , Adulto , Fatores de Risco Cardiometabólico , Humanos , Obesidade Abdominal/epidemiologia , Estudos Prospectivos , Fatores de Risco , Adulto Jovem
5.
Cells ; 10(8)2021 07 26.
Artigo em Inglês | MEDLINE | ID: mdl-34440660

RESUMO

Triple-negative breast cancer (TNBC) is the most malignant subtype of breast cancer as it shows a high capacity for metastasis and poor prognoses. Metabolic reprogramming is one of the hallmarks of cancer, and aberrant glycolysis was reported to be upregulated in TNBC. Thus, identifying metabolic biomarkers for diagnoses and investigating cross-talk between glycolysis and invasiveness could potentially enable the development of therapeutics for patients with TNBC. In order to determine novel and reliable metabolic biomarkers for predicting clinical outcomes of TNBC, we analyzed transcriptome levels of glycolysis-related genes in various subtypes of breast cancer from public databases and identified a distinct glycolysis gene signature, which included ENO1, SLC2A6, LDHA, PFKP, PGAM1, and GPI, that was elevated and associated with poorer prognoses of TNBC patients. Notably, we found a transcription factor named Y-box-binding protein 1 (YBX1) to be strongly associated with this glycolysis gene signature, and it was overexpressed in TNBC. A mechanistic study further validated that YBX1 was upregulated in TNBC cell lines, and knockdown of YBX1 suppressed expression of those glycolytic genes. Moreover, YBX1 expression was positively associated with epithelial-to-mesenchymal transition (EMT) genes in breast cancer patients, and suppression of YBX1 downregulated expressions of EMT-related genes and tumor migration and invasion in MDA-MB-231 and BT549 TNBC cells. Our data revealed an YBX1-glycolysis-EMT network as an attractive diagnostic marker and metabolic target in TNBC patients.


Assuntos
Biomarcadores Tumorais/metabolismo , Glicólise , Transcriptoma , Neoplasias de Mama Triplo Negativas/metabolismo , Proteína 1 de Ligação a Y-Box/metabolismo , Biomarcadores Tumorais/genética , Movimento Celular , Transição Epitelial-Mesenquimal , Feminino , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Glicólise/genética , Humanos , Células MCF-7 , Invasividade Neoplásica , Prognóstico , Neoplasias de Mama Triplo Negativas/genética , Neoplasias de Mama Triplo Negativas/patologia , Proteína 1 de Ligação a Y-Box/genética
6.
Biometals ; 23(3): 543-54, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20148305

RESUMO

In this study, Lactobacillus casei was used to deliver and express human lactoferrin (hLF) to protect the host against bacterial infection. Full-length hLF cDNA was cloned into a Lactobacillus-specific plasmid to produce the L. casei transformants (rhLF/L. casei). Antimicrobial activity of recombinant hLF was examined in inhibition of bacteria growth in vitro. A mouse model was established to test in vivo antibacterial activity and protective effect of orally-administered probiotic L. casei transformant in the gastrointestinal tract. Trials were conducted in which animals were challenged with E. coli ATCC25922. E. coli colony numbers in duodenal fluid from the group fed with rhLF/L. casei were significantly lower than those of the group fed with wild-type L. casei or placebo (P < 0.01). Histopathological analyses of the small intestine, showed both decreased intestinal injury and increased villi length were observed in the mice fed with rhLF/L. casei as compared with the control groups (P < 0.01). Our results demonstrate that L. casei expressing hLF exhibited antibacterial activity both in in vitro and in vivo. It also provides a potentially large-scale production of hLF as applications for treatment of infections caused by clinically relevant pathogens.


Assuntos
Antibacterianos/metabolismo , Trato Gastrointestinal/microbiologia , Lacticaseibacillus casei/genética , Lacticaseibacillus casei/metabolismo , Lactoferrina/metabolismo , Probióticos/metabolismo , Animais , Antibacterianos/administração & dosagem , Escherichia coli/crescimento & desenvolvimento , Trato Gastrointestinal/patologia , Humanos , Lacticaseibacillus casei/citologia , Lactoferrina/biossíntese , Lactoferrina/genética , Camundongos , Camundongos Endogâmicos ICR , Testes de Sensibilidade Microbiana , Proteínas Recombinantes/biossíntese , Relação Estrutura-Atividade
7.
Biometals ; 23(3): 579-87, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20237823

RESUMO

In this study, recombinant porcine lactoferrin (PLF) was used as feedstuff additive to investigate the effects of peripheral lymphocyte proliferation and serum antibody titers in chickens vaccinated against the infectious bursal disease (IBD) virus. Treatment groups were fed three doses of PLF powder in their diet (0.5, 1.0, and 2.0% w/w), and the IBD vaccine was administrated at 1 and 3 weeks of age. At 8, 12, and 16 weeks after vaccination, serum IBD antibody titers were measured via the micro-method and T cell proliferation rates were evaluated. The results revealed that a high dose of PLF led to significant increases in serum IgA, IgG and IBD-specific antibody titers (P < 0.05). PLF administration, at either low or high doses, enhanced the expression of IFN-gamma and IL-12 in chicken T lymphocytes. These results suggest that PLF enhances cell-mediated immunity and augment the ability of IBD vaccination to strengthen subsequent anti-viral responses.


Assuntos
Ração Animal , Galinhas/imunologia , Aditivos Alimentares/farmacologia , Vírus da Doença Infecciosa da Bursa/imunologia , Lactoferrina/administração & dosagem , Lactoferrina/imunologia , Vacinas Virais/imunologia , Animais , Infecções por Birnaviridae/imunologia , Infecções por Birnaviridae/prevenção & controle , Infecções por Birnaviridae/veterinária , Proliferação de Células , Galinhas/sangue , Galinhas/virologia , Aditivos Alimentares/administração & dosagem , Imunidade Ativa/imunologia , Leucócitos Mononucleares/imunologia , Proteínas Recombinantes/administração & dosagem , Proteínas Recombinantes/imunologia , Suínos , Vacinação
8.
Theranostics ; 9(9): 2526-2540, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31131051

RESUMO

Rationale: Cancer cells reprogram cellular metabolism to fulfill their needs for rapid growth and metastasis. However, the mechanism controlling this reprogramming is poorly understood. We searched for upregulated signaling in metastatic colorectal cancer and investigated the mechanism by which Glut3 promotes tumor metastasis. Methods: We compared RNA levels and glycolytic capacity in primary and metastatic colon cancer. The expression and association of Glut3 with clinical prognosis in colon cancer tissues was determined by immunohistochemistry. Glut3 gain-of-function and loss-of-function were established using colon cancer HCT116, HT29, and metastatic 116-LM cells, and tumor invasiveness and stemness properties were evaluated. Metabolomic profiles were analyzed by GC/MS and CE-TOF/MS. The metastatic burden in mice fed a high-fat sucrose diet was assessed by intravenous inoculation with Glut3 knockdown 116-LM cells. Results: Upregulation of glycolytic genes and glycolytic capacity was detected in metastatic colorectal cancer cells. Specifically, Glut3 overexpression was associated with metastasis and poor survival in colorectal cancer patients. Mechanistically, Glut3 promoted invasiveness and stemness in a Yes-associated protein (YAP)-dependent manner. Activation of YAP in turn transactivated Glut3 and regulated a group of glycolytic genes. Interestingly, the expression and phosphorylation of PKM2 were concomitantly upregulated in metastatic colorectal cancer, and it was found to interact with YAP and enhance the expression of Glut3. Importantly, a high-fat high-sucrose diet promoted tumor metastasis, whereas the inhibition of either Glut3 or YAP effectively reduced the metastatic burden. Conclusion: Activation of the Glut3-YAP signaling pathway acts as a master activator to reprogram cancer metabolism and thereby promotes metastasis. Our findings reveal the importance of metabolic reprogramming in supporting cancer metastasis as well as possible therapeutic targets.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/genética , Adenocarcinoma/genética , Transformação Celular Neoplásica/genética , Neoplasias do Colo/genética , Regulação Neoplásica da Expressão Gênica , Transportador de Glucose Tipo 3/genética , Fatores de Transcrição/genética , Proteínas Adaptadoras de Transdução de Sinal/antagonistas & inibidores , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Adenocarcinoma/diagnóstico , Adenocarcinoma/mortalidade , Adenocarcinoma/patologia , Animais , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Proliferação de Células , Transformação Celular Neoplásica/metabolismo , Transformação Celular Neoplásica/patologia , Neoplasias do Colo/diagnóstico , Neoplasias do Colo/mortalidade , Neoplasias do Colo/patologia , Dieta Hiperlipídica/efeitos adversos , Transportador de Glucose Tipo 3/agonistas , Transportador de Glucose Tipo 3/antagonistas & inibidores , Transportador de Glucose Tipo 3/metabolismo , Glicólise/genética , Células HCT116 , Células HT29 , Humanos , Metástase Linfática , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Nus , Prognóstico , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Transdução de Sinais , Análise de Sobrevida , Hormônios Tireóideos/genética , Hormônios Tireóideos/metabolismo , Fatores de Transcrição/antagonistas & inibidores , Fatores de Transcrição/metabolismo , Ensaios Antitumorais Modelo de Xenoenxerto , Proteínas de Sinalização YAP , Proteínas de Ligação a Hormônio da Tireoide
9.
J Virol Methods ; 133(2): 158-66, 2006 May.
Artigo em Inglês | MEDLINE | ID: mdl-16384612

RESUMO

Epstein-Barr virus (EBV) genome-chips are employed to determine the EBV infection rate and to reveal the gene expression patterns of EBV in tumor biopsies. These chips are produced with 71 consecutive PCR-amplified EBV DNA fragments of 1-3 kbp covering the entire EBV genome. The specificity of the EBV-chips is determined by hybridizing the DNA on the chips with biotin-labeled cDNA probes reverse transcribed from the mRNA of P3HR1 cells, which were B-cell infected latently by EBV. Hybridization results revealed only the expression of EBNA1, EBNA2, EBER1 and EBER2 in these cells. On the other hand, EBV lytic genes are expressed after the cells are treated with 12-O-tetradecanoylphorbol-13-acetate and sodium butyrate to induce the EBV lytic cycle. Fourty-four tumor biopsies from different organs are assayed with these chips, which showed many defined and interesting EBV gene expression patterns. This study demonstrates that the EBV-chip is useful for screening infection with EBV in tumors, which may lead to insights into tumorigenesis associated with this virus.


Assuntos
Infecções por Vírus Epstein-Barr/virologia , Regulação Neoplásica da Expressão Gênica , Regulação Viral da Expressão Gênica , Herpesvirus Humano 4/genética , Análise em Microsséries/métodos , Neoplasias/virologia , Linfócitos B/citologia , Linfócitos B/efeitos dos fármacos , Linfócitos B/virologia , Linfoma de Burkitt/patologia , Butiratos/farmacologia , Linhagem Celular Tumoral , DNA Viral/genética , Estudos de Avaliação como Assunto , Perfilação da Expressão Gênica , Genes Virais , Genoma Viral , Humanos , RNA Mensageiro/metabolismo , Acetato de Tetradecanoilforbol/farmacologia
10.
J Agric Food Chem ; 54(21): 8041-7, 2006 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-17032007

RESUMO

Reactive oxygen species are associated with various diseases including cardiovascular diseases, neurological disorders, and pulmonary diseases. Extracellular superoxide dismutase (ECSOD) is an antioxidant enzyme secreted by cells to prevent overproduction of reactive oxygen species. We expressed an ECSOD gene isolated from a human aortic smooth muscle cDNA library in the methylotrophic yeast Pichia pastoris. A synthetic secretion cassette was constructed with the inducible promoter of the alcohol oxidase 1 gene (AOX1) and the yeast alpha-mating factor signal peptide. As much as 25% of the total protein was ECSOD in some transformants grown under inducing conditions. After 36 h of methanol induction, ECSOD was exported into the culture medium at a concentration of approximately 440 mg/L with an antioxidative activity of 760 +/- 20 U/mg ECSOD. Transformed yeast cells were more resistant to heat shock and H(2)O(2) oxidative stress, indicating that the human ECSOD expressed by P. pastoris had multiple biological functions. Our data suggest that the methylotrophic yeast inducible system is suitable for large-scale production of enzymatically active human ECSOD.


Assuntos
Expressão Gênica , Pichia/enzimologia , Superóxido Dismutase/genética , Aorta , Clonagem Molecular , Biblioteca Gênica , Temperatura Alta , Humanos , Músculo Liso Vascular/enzimologia , Estresse Oxidativo , Pichia/crescimento & desenvolvimento , Superóxido Dismutase/metabolismo , Transfecção
11.
Mol Nutr Food Res ; 55(7): 1036-43, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21538854

RESUMO

SCOPE: We investigated the inhibition of pulmonary tumor formation through treatment with curcumin in transgenic mice. METHODS AND RESULTS: In this study, a strain of transgenic mice carrying human vascular endothelial growth factor A165 (hVEGF-A165) gene to induce pulmonary tumor was used as an in vivo cancer therapy model. We found that curcumin significantly reduced hVEGF-A165 overexpression to normal, specifically in Clara cells of the lungs of transgenic mice, and suppressed the formation of tumors. In addition, we demonstrated a relationship between curcumin treatment and the expression of VEGF, EGFR, ERK2, and Cyclin A at the transcriptional and translational levels. We also noticed a reduction of Cyclin A and Cyclin B after curcumin treatment that had an effect on the cell cycle. Curcumin-induced inhibition of Cyclin A and Cyclin B likely results in decreased progression through S and G2/M phases. These results demonstrated that the expression of proteins involved in the S to M phase transition in transgenic mice is suppressed by curcumin. CONCLUSION: A Data suggest that a blockade of the cell cycle may be a critical mechanism for the observed effects on vasculogenesis and angiogenesis following treatment with curcumin.


Assuntos
Curcumina/farmacologia , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/fisiopatologia , Fator A de Crescimento do Endotélio Vascular/genética , Animais , Western Blotting , Ciclo Celular/efeitos dos fármacos , Ciclo Celular/fisiologia , Ciclina A/efeitos dos fármacos , Ciclina A/genética , Ciclina B/efeitos dos fármacos , Ciclina B/genética , Ensaios de Seleção de Medicamentos Antitumorais , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Genes erbB-1/efeitos dos fármacos , Marcadores Genéticos/efeitos dos fármacos , Humanos , Neoplasias Pulmonares/patologia , Camundongos , Camundongos Transgênicos , RNA Mensageiro , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais/efeitos dos fármacos
12.
PLoS One ; 6(10): e26870, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-22046389

RESUMO

An important issue in critical care medicine is the identification of ways to protect the lungs from oxygen toxicity and reduce systemic oxidative stress in conditions requiring mechanical ventilation and high levels of oxygen. One way to prevent oxygen toxicity is to augment antioxidant enzyme activity in the respiratory system. The current study investigated the ability of aerosolized extracellular superoxide dismutase (EC-SOD) to protect the lungs from hyperoxic injury. Recombinant human EC-SOD (rhEC-SOD) was produced from a synthetic cassette constructed in the methylotrophic yeast Pichia pastoris. Female CD-1 mice were exposed in hyperoxia (FiO2>95%) to induce lung injury. The therapeutic effects of EC-SOD and copper-zinc SOD (CuZn-SOD) via an aerosol delivery system for lung injury and systemic oxidative stress at 24, 48, 72 and 96 h of hyperoxia were measured by bronchoalveolar lavage, wet/dry ratio, lung histology, and 8-oxo-2'-deoxyguanosine (8-oxo-dG) in lung and liver tissues. After exposure to hyperoxia, the wet/dry weight ratio remained stable before day 2 but increased significantly after day 3. The levels of oxidative biomarker 8-oxo-dG in the lung and liver were significantly decreased on day 2 (P<0.01) but the marker in the liver increased abruptly after day 3 of hyperoxia when the mortality increased. Treatment with aerosolized rhEC-SOD increased the survival rate at day 3 under hyperoxia to 95.8%, which was significantly higher than that of the control group (57.1%), albumin treated group (33.3%), and CuZn-SOD treated group (75%). The protective effects of EC-SOD against hyperoxia were further confirmed by reduced lung edema and systemic oxidative stress. Aerosolized EC-SOD protected mice against oxygen toxicity and reduced mortality in a hyperoxic model. The results encourage the use of an aerosol therapy with EC-SOD in intensive care units to reduce oxidative injury in patients with severe hypoxemic respiratory failure, including acute respiratory distress syndrome (ARDS).


Assuntos
Hiperóxia/prevenção & controle , Lesão Pulmonar/prevenção & controle , Superóxido Dismutase/administração & dosagem , 8-Hidroxi-2'-Desoxiguanosina , Administração por Inalação , Animais , Biomarcadores/análise , Desoxiguanosina/análogos & derivados , Desoxiguanosina/análise , Feminino , Humanos , Hiperóxia/complicações , Fígado/metabolismo , Pulmão/metabolismo , Lesão Pulmonar/mortalidade , Camundongos , Síndrome do Desconforto Respiratório/prevenção & controle , Resultado do Tratamento
13.
Biomicrofluidics ; 1(3): 34104, 2007 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-19693360

RESUMO

A novel microstirring strategy is applied to accelerate the digestion rate of the substrate N(alpha)-benzoyl-L-arginine-4-nitroanilide (L-BAPA) catalyzed by sol-gel encapsulated trypsin. We use an ac nonlinear electrokinetic vortex flow to stir the solution in a microfluidic reaction chamber to reduce the diffusion length between the immobilized enzyme and substrate in the solution. High-intensity nonlinear electroosmotic microvortices, with angular speeds in excess of 1 cms, are generated around a small ( approximately 1.2 mm) conductive ion exchange granule when ac electric fields (133 Vcm) are applied across a miniature chamber smaller than 10 mul. Coupling between these microvortices and the on-and-off electrophoretic motion of the granule in low frequency (0.1 Hz) ac fields produces chaotic stream lines to stir substrate molecules sufficiently. We demonstrate that, within a 5-min digestion period, the catalytic reaction rate of immobilized trypsin increases almost 30-fold with adequate reproducibility (15%) due to sufficient stirring action through the introduction of the nonlinear electrokinetic vortices. In contrast, low-frequency ac electroosmotic flow without the granule, provides limited stirring action and increases the reaction rate approximately ninefold with barely acceptable reproducibility (30%). Dye molecules are used to characterize the increases in solute diffusivity in the reaction reservoir in which sol-gel particles are placed, with and without the presence of granule, and compared with the static case. The solute diffusivity enhancement data show respective increases of approximately 30 and approximately 8 times, with and without the presence of granule. These numbers are consistent with the ratios of the enhanced reaction rate.

14.
J Mol Microbiol Biotechnol ; 8(3): 141-9, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-16088216

RESUMO

Lactoferrin is a metal-binding glycoprotein exhibiting multifunctional immunoregulation of antibacterial, antioxidant, anti-endotoxin and antiviral activities. Uptake of porcine lactoferrin (PLF) has been shown to enhance resistance to diarrhea and anemia in neonatal piglets. In this study, the methylotrophic yeast, Pichia pastoris, was used to express a recombinant PLF (rPLF) gene from swine mammary gland. A synthetic secretion cassette was constructed using the inducible promoter of the alcohol oxidase-1 gene (AOX1) and the yeast alpha-mating factor signal peptide. After electroporation and Zeocin selection, several clones expressed high levels of rPLF protein which constitutes more than 30% of the total protein. A time-course study showed that rPLF mRNA transcripts are stably expressed during 120 h of culture induction. rPLF was exported into the culture supernatant at approximately 87 mg/l and a large portion of rPLF was accumulated in the cell cytoplasm at approximately 760 mg/l after 72 h of methanol induction. Recombinant PLF protein was purified via a heparin column using a fast protein liquid chromatography system. The glycosylation of P. pastoris-derived rPLF was analyzed and similar patterns to milk PLF were observed. Pepsin hydrolysate of rPLF displayed high bactericidal activity against Escherichia coli ATCC 25922 under scanning electron microscopy observation and minimal inhibitory concentration and minimal bactericidal concentration tests. Our results suggested that the methylotrophic yeast-inducible system is suitable for large-scale production of active antibacterial rPLF glycoprotein.


Assuntos
Antibacterianos/farmacologia , Lactoferrina/farmacologia , Pichia/metabolismo , Animais , Antibacterianos/isolamento & purificação , Sequência de Bases , Clonagem Molecular , Escherichia coli/efeitos dos fármacos , Lactoferrina/genética , Lactoferrina/isolamento & purificação , Testes de Sensibilidade Microbiana , Microscopia Eletrônica de Varredura , Dados de Sequência Molecular , Peptídeos/genética , Peptídeos/isolamento & purificação , Peptídeos/farmacologia , Pichia/genética , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/farmacologia , Suínos
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