Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 13 de 13
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
J Nurs Res ; 28(4): e106, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32379107

RESUMO

BACKGROUND: Although studies on the effectiveness of self-management in limiting fluid intake in patients on hemodialysis have been conducted extensively, xerostomia, which is a powerful stimulus of fluid intake, has received scarce attention. PURPOSE: The purpose of this study was to examine the effects of a 4-week auricular acupressure treatment on xerostomia, salivary flow rate, interdialytic weight gain, constipation, and diet-related quality of life in patients on hemodialysis in Korea. METHODS: This was a randomized controlled trial. Sixty patients on hemodialysis were randomly assigned to either the experimental group (n = 30) or the control group (n = 30). The experimental group received an auricular acupressure intervention, which included the application of skin tape with a Semen vaccariae seed on the five auricular acupoints, including the large intestine (CO7), San Jiao (CO17), middle triangular fossa (TF3), spleen (CO13), and upper tragus (TG1), for 4 weeks. The control group received only the application of skin tape without a seed on the same auricular acupoints for the same period. The outcome variables were as follows: xerostomia, measured using the visual analog scale; salivary flow rate, measured using the unstimulated whole saliva absorbed in oral cotton; interdialytic weight gain; the constipation assessment scale score; and the Quality of Life Related to Dietary Change Questionnaire results. RESULTS: The experimental group scored significantly better than the control group in terms of xerostomia (p = .004), salivary flow rate (p = .010), constipation (p = .009), and diet-related quality of life (p < .001). CONCLUSIONS/IMPLICATIONS FOR PRACTICE: Auricular acupressure may be an important tool for alleviating the negative symptoms of xerostomia and for improving quality of life in patients on hemodialysis. Nurses caring for patients on hemodialysis with both xerostomia and constipation may teach auricular acupressure to help patients self-manage their discomfort.


Assuntos
Acupuntura Auricular/normas , Manejo da Dor/normas , Diálise Renal/métodos , Acupuntura Auricular/métodos , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Manejo da Dor/métodos , Manejo da Dor/estatística & dados numéricos , Medição da Dor/métodos , República da Coreia , Inquéritos e Questionários
2.
Korean J Intern Med ; 33(3): 568-576, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-28298077

RESUMO

BACKGROUND/AIMS: Colchicine is an established drug for microtubule stabilization that may reduce tissue injury. No data were available that its effects may depend on the dosage of colchicine. We investigated the anti-fibrotic and apoptotic effects of various dose of colchicine in a unilateral ureteral obstruction (UUO) model. METHODS: Thirty-six Sprague-Dawley rats were randomly assigned into six groups. Two sham groups were divided into a vehicle-treated or colchicine-treated group (100 µg/kg/day). Four UUO groups were treated with either vehicle or three different doses of colchicine for 7 days (30, 60, and 100 µg/kg/day, intraperitoneally). All of the animals were sacrificed on day 7. RESULTS: Colchicine treatment diminished acetylated α-tubulin and tumor growth factor-ß immunoreactivities in the cortical area of the 7-day obstructed kidneys, which was in dose dependent manner. Colchicine attenuated tubulointerstitial damage and apoptosis in both cortical and medullary area, and beneficial effects of colchicine therapy were dramatically shown at the higher dosage of colchicine. The expression levels of cleaved caspase-3, ED-1, and fibronectin were decreased in UUO animals. CONCLUSIONS: We found that the proper dosage of colchicine may have anti-fibrotic and anti-apoptotic effects in obstructed kidneys. For clinical applications, an optimal dose of colchicine should be evaluated to maximize the prevention of renal disease progression.


Assuntos
Apoptose , Colchicina , Rim , Moduladores de Tubulina , Obstrução Ureteral , Animais , Apoptose/efeitos dos fármacos , Colchicina/farmacologia , Modelos Animais de Doenças , Fibrose/tratamento farmacológico , Rim/patologia , Masculino , Camundongos , Coelhos , Distribuição Aleatória , Ratos , Ratos Sprague-Dawley , Moduladores de Tubulina/farmacologia , Obstrução Ureteral/tratamento farmacológico
3.
Nephrology (Carlton) ; 21(7): 574-82, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-26869361

RESUMO

AIM: To investigate the effect of microtubule stabilization with low-dose paclitaxel on renal fibrosis, focusing on the transforming growth factor-ß1 (TGF-ß1)-induced plasminogen activator inhibitor-1 (PAI-1) signaling cascade. METHODS: Forty-eight rats were randomly assigned to four groups: sham/vehicle, sham/paclitaxel, unilateral ureteral obstruction (UUO)/vehicle and UUO/paclitaxel. Rats were treated with a 0.3 mg/kg intraperitoneal dose of paclitaxel or vehicle twice per week for 14 days. Half of the rats in each group were sacrificed respectively on day 7 and 14 after operation. Inner medullar collecting duct (IMCD) cells stimulated with TGF-ß1 were incubated with 0, 1 and 2 nM paclitaxel for 24 and 72 hours. Histological changes were assessed using periodic acid-Schiff and Masson's trichrome. The TGF-ß1-induced PAI-1 signaling and status of extracellular matrix proteins were evaluated by western blot analysis. RESULTS: In the UUO kidneys, paclitaxel significantly attenuated tubular damage and interstitial collagen deposition, as well as α-smooth muscle actin (α-SMA), TGF-ß1 and PAI-1 protein expression. Paclitaxel also inhibited the UUO-induced activation of Smad2/3 and c-Jun N-terminal kinase (JNK). However, paclitaxel treatment did not inhibit extracellular signal-regulated kinase 1/2 (ERK1/2) or p38 expression. In TGF-ß1-treated IMCD cells, treatment with 1 and 2 nM paclitaxel for 72 h reduced fibronectin, α-SMA and PAI-1 protein expression. Moreover, a 2 nM dose of paclitaxel for 24 h significantly inhibited the TGF-ß1-stimulated activation of Smad2/3, JNK and ERK1/2 in IMCD cells. CONCLUSION: Paclitaxel at low non-cytotoxic doses ameliorates renal fibrosis by inhibiting multiple steps in the TGF-ß1-induced PAI-1 signaling including Smads and mitogen-activated protein kinases.


Assuntos
Nefropatias/tratamento farmacológico , Rim/efeitos dos fármacos , Paclitaxel/administração & dosagem , Inibidor 1 de Ativador de Plasminogênio/metabolismo , Transdução de Sinais/efeitos dos fármacos , Fator de Crescimento Transformador beta1/metabolismo , Moduladores de Tubulina/administração & dosagem , Animais , Células Cultivadas , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Ativação Enzimática , Proteínas da Matriz Extracelular/metabolismo , Fibrose , Rim/metabolismo , Rim/patologia , Nefropatias/etiologia , Nefropatias/metabolismo , Nefropatias/patologia , Masculino , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Ratos Sprague-Dawley , Proteína Smad2/metabolismo , Proteína Smad3/metabolismo , Fatores de Tempo , Obstrução Ureteral/complicações
4.
J Korean Med Sci ; 29(12): 1658-64, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25469066

RESUMO

Metabolic acidosis, which is observed in salt-sensitive hypertension, is also associated with kidney injury. Alkali therapy in chronic renal failure (CRF) may ameliorate the progression of kidney disease; however, few studies have examined the effects of alkali therapy on salt sensitivity and kidney injury in CRF. We randomly administered standard diet (SD), sodium chloride with 20% casein diet (NACL), or sodium citrate with 20% casein diet (NACT) to Sprague-Dawley rats after a CRF or a sham operation. Four weeks after 5/6 nephrectomy, serum bicarbonate levels were higher in the NACT-treated group. On the pressure-natriuresis curve, NACT-treated CRF rats were more salt-resistant than NACL-treated CRF rats. Additionally, the NACT-treated CRF group showed less tubulointerstitial damage than the NACL-treated CRF group. The expression and immunoreactivity of NHE3 in the kidney in the NACT-treated CRF group were lower than those in the NACL-treated CRF group. We observed that dietary NACT as alkali therapy in CRF might improve the altered salt-sensitivity and ameliorate the progression of kidney injury compared to the NACL diet, which may be related to reduced renal NHE3 expression.


Assuntos
Injúria Renal Aguda/tratamento farmacológico , Injúria Renal Aguda/fisiopatologia , Citratos/administração & dosagem , Suplementos Nutricionais , Falência Renal Crônica/dietoterapia , Falência Renal Crônica/fisiopatologia , Tolerância ao Sal/efeitos dos fármacos , Injúria Renal Aguda/diagnóstico , Administração Oral , Animais , Masculino , Ratos , Ratos Sprague-Dawley , Citrato de Sódio , Resultado do Tratamento
5.
Tohoku J Exp Med ; 230(2): 117-21, 2013 06.
Artigo em Inglês | MEDLINE | ID: mdl-23782720

RESUMO

Most dialysis centers adopt a standard dialysate sodium prescription. While pre-hemodialysis (HD) serum sodium levels remain relatively constant in each individual patient on chronic HD, these levels can vary between different patients. Therefore, a single dialysate sodium prescription may not be appropriate for all patients. Nineteen stable patients on maintenance HD were dialyzed for 9 HD sessions with their current dialysis solutions, followed by another 9 sessions using individualized prescriptions created by aligning dialysate sodium levels to each patient's serum sodium concentration. Patients were divided into 2 groups according to whether the average pre-HD serum sodium concentration was higher than (higher serum sodium group, n = 13) or equal to (equal sodium group, n = 5) the standard dialysate sodium concentration. Pre-HD serum sodium levels remained constant during entire study period in both groups. In higher serum sodium group, interdialytic weight gain increased after implementation of the sodium alignment (2.0 ± 0.3 kg vs. 2.3 ± 0.4 kg; P = 0.008). Thirst scores also increased in patients whose dialysate sodium was increased by 4 mmol/L (n = 7) (6.4 ± 1.5 vs. 7.6 ± 1.5, P = 0.015). There were no significant changes in blood pressure and intradialytic complications. In equal sodium group, significant differences were not observed in any parameters. Our results suggest that alignment of dialysate sodium levels to each patient's serum sodium concentration is of little benefit in hemodynamically stable patients who have pre-HD serum sodium concentrations higher than dialysate sodium concentration.


Assuntos
Soluções para Hemodiálise/administração & dosagem , Falência Renal Crônica/sangue , Falência Renal Crônica/terapia , Diálise Renal/efeitos adversos , Sódio/administração & dosagem , Sódio/sangue , Sede , Aumento de Peso , Adulto , Idoso , Pressão Sanguínea , Feminino , Soluções para Hemodiálise/química , Hemodinâmica , Humanos , Masculino , Pessoa de Meia-Idade , Qualidade de Vida
6.
Tohoku J Exp Med ; 228(2): 125-33, 2012 10.
Artigo em Inglês | MEDLINE | ID: mdl-22990525

RESUMO

Subtle fluid imbalance can cause poor clinical outcomes among hemodialysis patients. However, the traditional subjective assessment of fluid status may be inadequate. We evaluated whether the objective measurement and optimization of fluid status could be beneficial for hemodynamic and biochemical parameters in hemodialysis patients. We enrolled 120 hemodialysis patients, who were clinically euvolemic for at least 3 months. Based on the results of a body composition monitor, we divided the patients into the following two groups: the hyperhydrated group (post hemodialysis fluid overload ≥ 1.1 L) and the dehydrated group (post hemodialysis fluid overload < -1.1 L). We reduced the patient's body weight in the hyperhydrated group and raised the body weight in the dehydrated group towards normohydration (-1.1 L ≤ fluid overload < 1.1 L) for 16 weeks. Forty-four of 120 patients were in the hyperhydrated group, and 18 of 120 patients in the dehydrated group. After 16 weeks, systolic blood pressure and pulse pressure decreased in the hyperhydrated group, while there was no increase in blood pressure in the dehydrated group after the intervention. Serum levels of monocyte chemotactic protein-1, an inflammatory marker, gradually decreased in the hyperhydrated group, and serum adiponectin levels, an anti-atherogenic biomarker, increased in the two groups. We found that hyperhydrated patients contributed over 1/3 of the participants despite enrolling clinically euvolemic patients and that body composition monitor-guided optimization of body fluid status may lead to improvement of inflammatory markers and anti-atherogenic adipokines as well as hemodynamic parameters in hemodialysis patients.


Assuntos
Composição Corporal/fisiologia , Líquidos Corporais/fisiologia , Diálise Renal/efeitos adversos , Desequilíbrio Hidroeletrolítico/patologia , Adiponectina/sangue , Pressão Sanguínea/fisiologia , Peso Corporal/fisiologia , Quimiocina CCL2/sangue , Humanos , Monitorização Fisiológica/métodos , Diálise Renal/estatística & dados numéricos
7.
Am J Physiol Renal Physiol ; 300(6): F1422-30, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21389090

RESUMO

Dietary potassium is an important modulator of systemic blood pressure (BP). The purpose of this study was to determine whether dietary potassium is associated with an altered abundance of major renal sodium transporters that may contribute to the modulation of systemic BP. A unilateral nephrectomy (uNx) was performed in male Sprague-Dawley rats, and the rats were fed a normal-salt diet (0.3% NaCl) for 4 wk. Thereafter, the rats were fed a high-salt (HS) diet (3% NaCl) for the entire experimental period. The potassium-repleted (HS+KCl) group was given a mixed solution of 1% KCl as a substitute for drinking water. We examined the changes in the abundance of major renal sodium transporters and the expression of mRNA of With-No-Lysine (WNK) kinases sequentially at 1 and 3 wk. The systolic BP of the HS+KCl group was decreased compared with the HS group (140.3 ± 2.97 vs. 150.9 ± 4.04 mmHg at 1 wk; 180.3 ± 1.76 vs. 207.7 ± 6.21 mmHg at 3 wk). The protein abundances of type 3 Na(+)/H(+) exchanger (NHE3) and Na(+)-Cl(-) cotransporter (NCC) in the HS+KCl group were significantly decreased (53 and 45% of the HS group at 1 wk, respectively; 19 and 8% of HS group at 3 wk). WNK4 mRNA expression was significantly increased in the HS+KCl group (1.4-fold of control at 1 wk and 1.9-fold of control at 3 wk). The downregulation of NHE3 and NCC may contribute to the BP-attenuating effect of dietary potassium associated with increased urinary sodium excretion.


Assuntos
Hipertensão/metabolismo , Rim/metabolismo , Nefrectomia/métodos , Potássio na Dieta/metabolismo , Simportadores de Cloreto de Sódio/metabolismo , Simportadores de Cloreto de Sódio-Potássio/metabolismo , Animais , Hipertensão/fisiopatologia , Rim/efeitos dos fármacos , Rim/fisiopatologia , Masculino , Potássio na Dieta/farmacologia , Ratos , Ratos Sprague-Dawley , Cloreto de Sódio na Dieta/metabolismo , Cloreto de Sódio na Dieta/farmacologia , Estatísticas não Paramétricas
8.
Nephron Clin Pract ; 118(2): c122-9, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21150220

RESUMO

BACKGROUND/AIMS: Angiotensin II has been shown to play an important role in various renal diseases. Genetic polymorphisms of the renin-angiotensin system have been reported to be related to the clinical outcomes in immunoglobulin A nephropathy (IgAN). We investigated the association of polymorphisms of the genes encoding major angiotensin II-forming enzymes with the development and progression of IgAN among Korean patients. METHODS: A total of 261 IgAN patients and 300 healthy controls were studied. The polymorphisms of angiotensin-converting enzyme gene (I/D, A2350G) and chymase (CMA) gene (rs1800875, rs1800876) were determined. RESULTS: No significant difference was observed in the genotype and allele frequencies of the polymorphisms between IgAN patients and controls. The frequency of AA/AG genotypes of CMA rs1800875 and CC/CT genotype of CMA rs1800876 were significantly higher in patients with progressive disease course than in those with stable course (53.2 vs. 38.6%, p = 0.029; 89.6 vs. 78.3%, p = 0.031, respectively). In the Cox regression model with adjustment for clinical risk factors, CMA rs1800875 AA/AG genotypes remained an independent risk factor (hazard ratio 2.351; p = 0.001). CONCLUSION: Our results suggest that the CMA rs1800875 polymorphism is associated with the progression of IgAN in Korean patients.


Assuntos
Angiotensina II/genética , Povo Asiático/genética , Glomerulonefrite por IGA/genética , Peptidil Dipeptidase A/genética , Polimorfismo Genético/genética , Renina/genética , Adulto , Quimases/genética , Progressão da Doença , Feminino , Seguimentos , Frequência do Gene/fisiologia , Glomerulonefrite por IGA/enzimologia , Glomerulonefrite por IGA/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
9.
Electrolyte Blood Press ; 7(2): 58-66, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21468187

RESUMO

Uninephrectomy (uNx) in young rats causes salt-sensitive hypertension (SSH). Alterations of sodium handling in residual nephrons may play a role in the pathogenesis. Therefore, we evaluated the adaptive alterations of renal sodium transporters according to salt intake in uNx-SSH rats. uNx or sham operations were performed in male Sprague-Dawley rats, and normal-salt diet was fed for 4 weeks. Four experimental groups were used: sham-operated rats raised on a high-salt diet for 2 weeks (CHH) or on a low-salt diet for 1 week after 1 week's high-salt diet (CHL) and uNx rats fed on the same diet (NHH, NHL) as the sham-operated rats were fed. Expression of major renal sodium transporters were determined by semiquantitative immunoblotting. Systolic blood pressure was increased in NHH and NHL groups, compared with CHH and CHL, respectively. Protein abundances of Na(+)/K(+)/2Cl(-) cotransporter (NKCC2) and Na(+)/Cl(-) cotransporter (NCC) in the CHH group were lower than the CHL group. Expression of epithelial sodium channel (ENaC)-γ increased in the CHH group. In contrast, expressions of NKCC2 and NCC in the NHH group didn't show any significant alterations, compared to the NHL group. Expressions of ENaC-α and ENaC-ß in the NHH group were higher than the CHH group. Adaptive alterations of NKCC2 and NCC to changes of salt intake were different in the uNx group, and changes in ENaC-α and ENaC-ß were also different. These altered regulations of sodium transporters may be involved in the pathogenesis of SSH in the uNx rat model.

10.
Korean J Gastroenterol ; 50(5): 324-7, 2007 Nov.
Artigo em Coreano | MEDLINE | ID: mdl-18159165

RESUMO

Henoch-Schonlein purpura (H-S purpura) is a systemic small-vessel vasculitis involving skin, joint, gastrointestinal tract, and kidney. It is characterized by the classic tetrad of abdominal pain, arthralgia, typical rash, and renal involvement. All of these clinical findings can occur in any order and at any time over several days to weeks. Gastrointestinal manifestations such as abdominal pain, melena, or hematochezia occur in 45-85% and preceed skin lesions up to 40% in H-S purpura. However, endoscopically proven gastrointestinal lesion is rare because majority of involved sites are small intestine. We report a case of Henoch-Schonlein purpura with terminal ileal ulcer, healed after treatment with high dose steroid, proven by colonoscopy.


Assuntos
Anti-Inflamatórios/uso terapêutico , Vasculite por IgA/diagnóstico , Doenças do Íleo/tratamento farmacológico , Prednisolona/uso terapêutico , Úlcera/tratamento farmacológico , Adulto , Colonoscopia , Humanos , Vasculite por IgA/complicações , Vasculite por IgA/tratamento farmacológico , Doenças do Íleo/etiologia , Doenças do Íleo/patologia , Perna (Membro)/patologia , Masculino , Úlcera/etiologia , Úlcera/patologia
11.
Korean J Gastroenterol ; 48(6): 401-7, 2006 Dec.
Artigo em Coreano | MEDLINE | ID: mdl-17189923

RESUMO

BACKGROUND/AIMS: Deterioration of renal function in patients with cirrhosis and spontaneous bacterial peritonitis (SBP) is the most sensitive predictor of in-hospital mortality. It has been shown that high dose intravenous albumin in addition to antibiotics reduces the incidence of renal impairment and improve hospital survival in these patients. Besides, it is important to know which patients would benefit from albumin infusion. Therefore, we conducted a retrospective study to elucidate the incidence and risk factors of renal dysfunction in cirrhotic patients with SBP. METHODS: All medical records of 76 consecutive episodes of SBP in 60 patients were analyzed. Renal dysfunction after SBP was defined as elevation of BUN >30 mg/dL or serum creatinine >1.5 mg/dL in patients without preexisting renal insufficiency, or elevation of more than 50% of the baseline level in patients with renal dysfunction at the diagnosis of infection. RESULTS: Of the 76 episodes, renal dysfunction was present in 31 (40.8%). Age, concurrent use of diuretics, large volume paracentesis (LVP) with volume expander, initial BUN and creatinine level were significant risk factors on univariate analysis. Of these, age and LVP were independent risk factors on logistic regression model. CONCLUSIONS: Renal dysfunction occurs in 40.8% of hospitalized patients after SBP. Considering poor prognosis of patients with renal dysfunction in SBP, close monitoring of renal function is needed and high dose intravenous albumin with antibiotics should be used especially in the elderly and those with LVP.


Assuntos
Infecções Bacterianas/diagnóstico , Nefropatias/diagnóstico , Cirrose Hepática/complicações , Peritonite/diagnóstico , Adulto , Idoso , Infecções Bacterianas/complicações , Feminino , Humanos , Incidência , Nefropatias/epidemiologia , Nefropatias/etiologia , Masculino , Pessoa de Meia-Idade , Peritonite/complicações , Peritonite/microbiologia , Fatores de Risco
12.
Korean J Gastroenterol ; 48(5): 321-6, 2006 Nov.
Artigo em Coreano | MEDLINE | ID: mdl-17132920

RESUMO

BACKGROUND/AIMS: Serum alpha-fetoprotein (AFP) is frequently used for the diagnosis of hepatocellular carcinoma (HCC). Most available data concerning AFP came from studies of patients with chronic hepatitis B or mixed etiologies. Studies concerning the diagnostic value of AFP for HCV-related liver cirrhosis (LC) are limited. We evaluated the factors influencing AFP elevation in the absence of HCC and analyzed the diagnostic value of serum AFP in HCC surveillance of HCV-related LC patients. METHODS: We enrolled 55 patients of HCV-related LC with HCC and 62 patients without HCC as a case-control study were analyzed. The sensitivity and specificity were calculated and the clinical and biochemical factors influencing serum AFP levels. RESULTS: The sensitivities and specificities of serum AFP for the detection of HCC in HCV-related LC were 72.7% and 59.7% for AFP>or=20 ng/mL, and 47.3% and 92.5% for AFP>or=100 ng/mL, respectively. Elevated serum AST was independently associated with elevated serum AFP level in HCV-related LC. In cases of ASTor=100 ng/mL for the diagnosis of HCC was 100%. However, in case of AST>2 ULN, the specificity was 85.0% for AFP>or=100 ng/mL and 95.0% for AFP>or=200 ng/mL. CONCLUSIONS: Serum AST levels influence serum AFP level in HCV-related LC. In cases of AST2 ULN.


Assuntos
Biomarcadores Tumorais/sangue , Carcinoma Hepatocelular/diagnóstico , Hepatite C/complicações , Cirrose Hepática/virologia , Neoplasias Hepáticas/diagnóstico , alfa-Fetoproteínas/análise , Idoso , Carcinoma Hepatocelular/complicações , Carcinoma Hepatocelular/patologia , Diagnóstico Diferencial , Feminino , Hepatite C/imunologia , Hepatite C/virologia , Humanos , Neoplasias Hepáticas/complicações , Neoplasias Hepáticas/patologia , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Sensibilidade e Especificidade
13.
Biotechnol Prog ; 21(4): 1335-40, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-16080720

RESUMO

Using immobilized recombinant Escherichia coli cells containing Geobacillus stearothermophilus l-arabinose isomerase mutant (Gali 152), we found that the galactose isomerization reaction was maximal at 70 degrees C and pH 7.0. Manganese ion enhanced galactose isomerization to tagatose. The immobilized cells were most stable at 60 degrees C and pH 7.0. The cell and substrate concentrations and dilution rate were optimal at 34 g/L, 300 g/L, and 0.05 h(-1), respectively. Under the optimum conditions, the immobilized cell reactor with Mn2+ produced an average of 59 g/L tagatose with a productivity of 2.9 g/L.h and a conversion yield of 19.5% for the first 20 days. The operational stability of immobilized cells with Mn2+ was demonstrated, and their half-life for tagatose production was 34 days. Tagatose production was compared for free and immobilized enzymes and free and immobilized cells using the same mass of cells. Immobilized cells produced the highest tagatose concentration, indicating that cell immobilization was more efficient for tagatose production than enzyme immobilization.


Assuntos
Aldose-Cetose Isomerases/genética , Escherichia coli/genética , Geobacillus stearothermophilus/enzimologia , Hexoses/biossíntese , Microbiologia Industrial/métodos , Aldose-Cetose Isomerases/metabolismo , Reatores Biológicos , Células Imobilizadas , Desenho de Equipamento , Escherichia coli/efeitos dos fármacos , Escherichia coli/metabolismo , Hexoses/genética , Concentração de Íons de Hidrogênio , Microbiologia Industrial/instrumentação , Manganês/farmacologia , Metais/metabolismo , Metais/farmacologia , Mutação , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Temperatura
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...