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1.
Clin Exp Med ; 24(1): 97, 2024 May 10.
Artículo en Inglés | MEDLINE | ID: mdl-38727756

RESUMEN

Data on the safety of Janus kinase inhibitors (JAKis) in patients with renal impairment are lacking. This study aimed to investigate the safety of JAKis compared to biological (b) DMARDs in patients with rheumatoid arthritis (RA) and renal impairment. We used a multi-centre observational registry of patients with RA in Japan (the ANSWER cohort). We assessed the drug retention rates of b/targeted synthetic DMARDs with different modes of action (tumour necrosis factor inhibitors (TNFis), immunoglobulins fused with cytotoxic T-lymphocyte antigen (CTLA-4-Ig), interleukin-6 receptor inhibitors (IL-6Ris), and JAKis) in patients with RA stratified by pre-treatment estimated glomerular filtration rate (eGFR) levels. The time to discontinuation of bDMARDs or JAKis was analysed using a multivariate Cox proportional hazards model This study included 3775 patients, who were classified into three groups (the normal group (eGFR ≥ 60 mL/min/1.73 m2): 2893 patients; CKDa group (eGFR 45-60 mL/min/1.73 m2): 551; and CKDb group (eGFR < 45 mL/min/1.73 m2): 331). In the CKDb group, the 12-month drug retention rate due to adverse events (AE) was the lowest in patients treated with JAKi (TNFi: 93.1%; IL-6Ri: 94.1%; CTLA-4-Ig: 92.3%; JAKi: 75.1%). In the normal and CKDa groups, drug retention rates due to AE were similar among patients treated with bDMARDs and JAKi. In contrast, drug retention rates due to inefficacy were similar between bDMARDs and JAKis in all groups. In the Cox-proportional model, in the CKDb group, TNFi, IL-6Ri, and CTLA-4-Ig showed lower incidence of drug discontinuation due to AE than JAKis (TNFi: hazard ratio = 0.23 (95% confidence interval 0.09-0.61), IL-6Ri: 0.34 (0.14-0.81), CTLA-4-Ig: 0.36 (0.15-0.89)). JAKis showed the lowest drug retention due to AE in patients with moderate-to-severe and severe renal impairment (eGFR < 45 mL/min/1.73 m2). Physicians should pay more attention to renal function when using JAKis than when using bDMARDs.


Asunto(s)
Antirreumáticos , Artritis Reumatoide , Inhibidores de las Cinasas Janus , Humanos , Artritis Reumatoide/tratamiento farmacológico , Femenino , Masculino , Persona de Mediana Edad , Inhibidores de las Cinasas Janus/uso terapéutico , Inhibidores de las Cinasas Janus/efectos adversos , Anciano , Antirreumáticos/uso terapéutico , Antirreumáticos/efectos adversos , Japón , Tasa de Filtración Glomerular , Insuficiencia Renal/inducido químicamente , Adulto , Estudios de Cohortes , Productos Biológicos/uso terapéutico , Productos Biológicos/efectos adversos
2.
Mod Rheumatol ; 34(3): 523-529, 2024 Mar 28.
Artículo en Inglés | MEDLINE | ID: mdl-37300805

RESUMEN

OBJECTIVES: Decreased sialylation of IgG-Fc glycans has been reported in autoimmune diseases, but its role in systemic lupus erythematosus (SLE) is not fully understood. In this study, we examined the pathogenicity of IgG desialylation and its association with Th17 in SLE using an animal model. METHODS: B6SKG mice, which develop lupus-like systemic autoimmunity due to the ZAP70 mutation, were used to investigate the pathogenicity of IgG desialylation. The proportion of sialylated IgG was compared between B6SKG and wild-type mice with or without ß-glucan treatment-induced Th17 expansion. Anti-interleukin (IL)-23 and anti-IL-17 antibodies were used to examine the role of Th17 cells in IgG glycosylation. Activation-induced cytidine deaminase-specific St6gal1 conditionally knockout (cKO) mice were generated to examine the direct effect of IgG desialylation. RESULTS: The proportions of sialylated IgG were similar between B6SKG and wild-type mice in the steady state. However, IgG desialylation was observed after ß-glucan-induced Th17 expansion, and nephropathy also worsened in B6SKG mice. Anti-IL-23/17 treatment suppressed IgG desialylation and nephropathy. Glomerular atrophy was observed in the cKO mice, suggesting that IgG desialylation is directly involved in disease exacerbation. CONCLUSIONS: IgG desialylation contributes to the progression of nephropathy, which is ameliorated by blocking IL-17A or IL-23 in an SLE mouse model.


Asunto(s)
Lupus Eritematoso Sistémico , beta-Glucanos , Ratones , Animales , Células Th17 , Virulencia , Lupus Eritematoso Sistémico/genética , Modelos Animales de Enfermedad , Inmunoglobulina G
3.
Rheumatology (Oxford) ; 63(2): 349-357, 2024 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-37354495

RESUMEN

OBJECTIVES: Anaemia, a common comorbidity of RA, is related to high disease activity and poor prognosis. It is unknown which biologic/targeted synthetic (b/ts)-DMARDs are optimal for patients with anaemia and RA in regulating anaemia and controlling disease activity. METHODS: We investigated the change in haemoglobin (Hb) levels, drug retention rates and disease activities after the administration of b/ts-DMARDs with different modes of action [TNF inhibitors (TNFis), immunoglobulin fused with cytotoxic T-lymphocyte antigen (CTLA-4-Ig), IL-6 receptor inhibitors (IL-6Ris) and Janus kinase inhibitors (JAKis)] in patients with RA stratified by baseline Hb levels using the multicentre observational registry for patients with RA in Japan (ANSWER cohort). RESULTS: A total of 2093 patients with RA were classified into three groups based on tertiles of the baseline Hb levels (Hblow, anaemic; Hbint, intermediate; Hbhigh, non-anaemic). IL-6Ri increased Hb levels in all groups (the mean change at 12 months in Hblow was +1.5 g/dl, Hbint +0.7 g/dl and Hbhigh +0.1 g/dl). JAKis increased the Hb level in patients with anaemia and RA and retained or decreased the Hb level in non-anaemic patients (the mean change at 12 months in Hblow was +0.6 g/dl, Hbint 0 g/dl and Hbhigh -0.3 g/dl). In patients with anaemia and RA, overall adjusted 3-year drug retention rates were higher in JAKi followed by IL-6Ri, CTLA4-Ig and TNFi (78.6%, 67.9%, 61.8% and 50.8%, respectively). Change of disease activity at 12 months was not different among different b/ts-DMARDs treatments. CONCLUSION: IL-6Ri and JAKi can effectively treat patients with anaemia and RA in a real-world setting.


Asunto(s)
Anemia , Antirreumáticos , Artritis Reumatoide , Inhibidores de las Cinasas Janus , Humanos , Inhibidores de las Cinasas Janus/uso terapéutico , Inhibidores de la Interleucina-6 , Estudios de Cohortes , Anemia/tratamiento farmacológico , Anemia/etiología , Artritis Reumatoide/complicaciones , Artritis Reumatoide/tratamiento farmacológico , Antirreumáticos/uso terapéutico
4.
Sci Rep ; 13(1): 10150, 2023 06 22.
Artículo en Inglés | MEDLINE | ID: mdl-37349495

RESUMEN

Advanced systemic sclerosis-associated interstitial lung disease (SSc-ILD) can be treated with lung transplantation. There is limited data on lung transplantation outcomes in patients with SSc-ILD, in non-Western populations.We assessed survival data of patients with SSc-ILD, on the lung transplant (LT) waiting list, and evaluated post-transplant outcomes in patients from an Asian LT center. In this single-center retrospective study, 29 patients with SSc-ILD, registered for deceased LT at Kyoto University Hospital, between 2010 and 2022, were identified. We investigated post-transplant outcomes in recipients who underwent LT for SSc-ILD, between February 2002 and April 2022. Ten patients received deceased-donor LT (34%), two received living-donor LT (7%), seven died waiting for LT (24%), and ten survived on the waiting list (34%). Median duration from registration to deceased-donor LT was 28.9 months and that from registration to living-donor LT or death was 6.5 months. Analysis of 15 recipients showed improved forced vital capacity with a median of 55.1% at baseline, 65.8% at 6 months, and 80.3% at 12 months post-transplant. The 5-year survival rate for post-transplant patients with SSc-ILD was 86.2%. The higher post-transplant survival rate at our institute than previously reported suggests that lung transplantation is acceptable in Asian patients with SSc-ILD.


Asunto(s)
Enfermedades Pulmonares Intersticiales , Trasplante de Pulmón , Esclerodermia Sistémica , Humanos , Estudios Retrospectivos , Enfermedades Pulmonares Intersticiales/cirugía , Enfermedades Pulmonares Intersticiales/complicaciones , Listas de Espera , Esclerodermia Sistémica/complicaciones , Esclerodermia Sistémica/cirugía , Pulmón , Pronóstico , Trasplante de Pulmón/efectos adversos
5.
Mod Rheumatol ; 33(5): 936-943, 2023 Aug 25.
Artículo en Inglés | MEDLINE | ID: mdl-36190743

RESUMEN

OBJECTIVES: Pulmonary nontuberculous mycobacterial disease (pNTM) is a common pulmonary complication of rheumatoid arthritis (RA), but their association has rarely been researched. We aimed to reveal the clinical characteristics of RA with pNTM. METHODS: Among all the RA patients who visited Tenri hospital from April 2017 to March 2018, we enrolled those fulfilling the 2007 ATS/IDSA diagnostic criteria of pNTM, and sex- and age- matched control group at a ratio of 1:5. Demographic characteristics were compared between the two groups. RESULTS: Among 865 RA patients, 35 (4.0%) patients were complicated with pNTM. RA patients with pNTM had significantly lower BMI and higher rheumatoid factor (RF) and anti-citrullinated protein antibody (ACPA) positivity. Bronchiectasis was the most frequent lesion, followed by clusters of small nodules, patchy consolidation and cavity. Multivariable logistic regression analysis revealed bronchiectasis as a strong independent associated factor of pNTM. Treatment for pNTM was needed in 14 of the 35 (40%) RA patients with pNTM and sputum negative conversion was accomplished in 11 of the 14 cases (78.6%). CONCLUSIONS: RA patients with lower BMI, RF/ACPA positivity, and bronchiectasis were associated with pNTM. Treatment for pNTM may attain sputum negative conversion and radiological improvement in patients with RA.


Asunto(s)
Artritis Reumatoide , Bronquiectasia , Infecciones por Mycobacterium no Tuberculosas , Humanos , Infecciones por Mycobacterium no Tuberculosas/complicaciones , Infecciones por Mycobacterium no Tuberculosas/diagnóstico , Estudios Transversales , Micobacterias no Tuberculosas , Artritis Reumatoide/complicaciones , Artritis Reumatoide/diagnóstico por imagen , Factor Reumatoide , Bronquiectasia/complicaciones , Bronquiectasia/diagnóstico por imagen
6.
Mod Rheumatol Case Rep ; 6(2): 270-272, 2022 06 24.
Artículo en Inglés | MEDLINE | ID: mdl-35388431

RESUMEN

Intestinal amoebiasis is caused by Entamoeba histolytica (E. histolytica) and is characterised by cecal lesions, multiple lesions, aphthae, and multiple exudative erosions. Intestinal Behçet's disease (BD) is a chronic inflammatory disorder that is characterised by multiple ulcers. Although the aetiologies of these two bowel diseases are unrelated, they are difficult to distinguish because they present similarly with inflammation and ulcers, especially if evidence of specific pathogens is not detected. Herein, we report a case of intestinal amoebiasis in a patient with BD. The patient underwent colonoscopy four times before intestinal amoebiasis was diagnosed. As intestinal BD was initially suspected, she received high-dose glucocorticoid therapy, which exacerbated her condition. Following exacerbation, she underwent colonoscopy, and E. histolytica was revealed. Deliberate care should be taken to distinguish between intestinal amoebiasis and intestinal BD, as the appropriate treatments for these diseases are entirely different.


Asunto(s)
Síndrome de Behçet , Disentería Amebiana , Enfermedades Intestinales , Síndrome de Behçet/complicaciones , Síndrome de Behçet/diagnóstico , Colonoscopía/efectos adversos , Disentería Amebiana/complicaciones , Disentería Amebiana/diagnóstico , Femenino , Humanos , Enfermedades Intestinales/etiología , Úlcera
7.
Rheumatol Int ; 42(7): 1227-1234, 2022 07.
Artículo en Inglés | MEDLINE | ID: mdl-35266034

RESUMEN

Rheumatoid factor (RF) binds to the fragment crystallizable (Fc) portion of immunoglobulin. It could bind to the Fc portion of anti-TNF inhibitors (TNFi) and attenuate the clinical efficacy. We tried to determine whether the therapeutic efficacy of TNFi with Fc might be lower than that of TNFi without Fc in rheumatoid arthritis (RA) patients with high titres of RF. The Kansai Consortium for Well-being of Rheumatic Disease Patients (ANSWER) cohort is an observational multi-center registry of patients with RA in the Kansai district of Japan. RA patients treated with TNFi were included and divided into two groups based on the structural characteristics between TNFi with Fc (infliximab, adalimumab, golimumab, and etanercept) and TNFi without Fc (certolizumab pegol). Patients were classified into 4 groups according to RF titre quartiles. The sequential disease activity score in 28 joints using erythrocyte sedimentation rate (DAS28-ESR) was compared by Mann-Whitney U test between TNFi with and without Fc in each RF titre group. Multiple linear regression analysis was used to analyze the effect of TNFi without Fc for the change of DAS28-ESR adjusted after potential confounders. A total of 705 RA patients were classified into four groups (RF1; RF 0-15.0 IU/mL, RF2; 15.0-55.0, RF3; 55.0-166, RF4; 166-7555). In RF4, RA patients treated with TNFi without Fc had a significantly lower DAS28-ESR than those treated with TNFi with Fc [3.2 (2.3-4.2) vs. 2.7 (2.0-3.0)] after 12 months. This effect of TNFi without Fc for the change of DAS28-ESR after 12 months treatment retained in multivariate analysis in RF4. TNFi without Fc may be more efficacious than TNFi with Fc in RA patients with high RF titres.


Asunto(s)
Antirreumáticos , Artritis Reumatoide , Adalimumab/uso terapéutico , Antirreumáticos/uso terapéutico , Artritis Reumatoide/diagnóstico , Artritis Reumatoide/tratamiento farmacológico , Estudios de Cohortes , Etanercept/uso terapéutico , Humanos , Infliximab/uso terapéutico , Factor Reumatoide , Inhibidores del Factor de Necrosis Tumoral , Factor de Necrosis Tumoral alfa
9.
Mod Rheumatol Case Rep ; 4(1): 16-20, 2020 01.
Artículo en Inglés | MEDLINE | ID: mdl-33086965

RESUMEN

An 18-year-old female was diagnosed with subclinical Cushing's syndrome (CS) due to a left adrenal adenoma. When she was 20 years old, she developed lupus nephritis. She was treated with high-dose prednisolone (PSL) and soon developed the symptoms of CS. When she was 25 years old, we evaluated her serum glucocorticoid level while she continued to take oral PSL. The result suggested her CS was affected by both the oral PSL and the endogenous cortisol secreted by the adrenocortical adenoma, which was therefore resected. Seven months after the operation, the patient's body weight was decreasing, and her SLE remained in clinical remission. CS complicated by SLE is rare, and the decision to surgically remove an adrenal tumor in such a case is even more rare.


Asunto(s)
Síndrome de Cushing/complicaciones , Lupus Eritematoso Sistémico/complicaciones , Lupus Eritematoso Sistémico/diagnóstico , Adolescente , Adenoma Corticosuprarrenal/diagnóstico , Adenoma Corticosuprarrenal/etiología , Adenoma Corticosuprarrenal/cirugía , Toma de Decisiones Clínicas , Síndrome de Cushing/diagnóstico , Manejo de la Enfermedad , Femenino , Glucocorticoides/sangre , Humanos , Nefritis Lúpica/diagnóstico , Nefritis Lúpica/tratamiento farmacológico , Nefritis Lúpica/etiología , Prednisolona/administración & dosificación , Resultado del Tratamiento
10.
JAMA Neurol ; 77(7): 872-877, 2020 07 01.
Artículo en Inglés | MEDLINE | ID: mdl-32310254

RESUMEN

Importance: Reports on dermatomyositis (DM) sine dermatitis (DMSD) are scarce, and the concept of the disease has not been widely accepted. Objective: To confirm the existence of DMSD, determine its prevalence, and characterize its serologic features. Design, Setting, and Participants: This is a cohort study that reviewed clinical information, laboratory data, and muscle pathology slides from January 2009 to August 2019. We further assessed the follow-up data of 14 patients with DMSD. The median (interquartile range) follow-up period was 34 (16-64) months. Muscle biopsy samples, along with clinical information and laboratory data, were sent to a referral center for muscle diseases in Japan for diagnosis. Of patients whose myopathologic diagnosis was made at the National Center of Neurology and Psychiatry between January 2009 and August 2019, 199 patients were eligible for inclusion. These patients underwent full investigation for DM-specific autoantibodies (against transcriptional intermediary factor γ, Mi-2, melanoma differentiation-associated gene 5, nuclear matrix protein 2 [NXP-2], and small ubiquitin-like modifier activating enzyme ); however, 17 patients were excluded because their muscle fibers did not express myxovirus resistance protein A, a sensitive and specific marker of DM muscle pathology. Main Outcomes and Measures: Diagnosis of DMSD was based on the absence of a skin rash at the time of muscle biopsy. Results: Of the 182 patients, 93 were women (51%) and 46 were children (25%) (<18 years). Fourteen patients (8%) had DMSD and none were clinically diagnosed with DM. Among the 14 patients with DMSD, 12 (86%) were positive for anti-NXP-2 autoantibodies, while the remaining 2 were positive for anti-transcriptional intermediary factor γ and anti-Mi-2 autoantibodies, respectively. Only 28% of patients (47 of 168) with a skin rash were positive for anti-NXP-2 autoantibodies, indicating a significant association between anti-NXP-2 autoantibodies and DMSD (86% [12 of 14] vs 28% [47 of 168]; P < .001). This association was also supported by multivariable models adjusted for disease duration (odds ratio, 126.47; 95% CI, 11.42-1400.64; P < .001). Conclusions and Relevance: Dermatomyositis sine dermatitis does exist and accounts for 8% of patients with DM confirmed with muscle biopsy. Dermatomyositis sine dermatitis is significantly associated with anti-NXP-2 autoantibodies, which contrasts with anti-MDA5 DM, which is typically clinically amyopathic in presentation. It is essential to distinguish DMSD from other types of myositis because DM-specific therapies that are currently under development, including Janus kinase inhibitors, may be effective for DMSD.


Asunto(s)
Autoanticuerpos/inmunología , Enfermedades Autoinmunes/inmunología , Proteínas de Unión al ADN/inmunología , Dermatomiositis/inmunología , Factores de Transcripción/inmunología , Adolescente , Adulto , Anciano , Autoantígenos/inmunología , Enfermedades Autoinmunes/patología , Niño , Estudios de Cohortes , Dermatitis , Dermatomiositis/patología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Adulto Joven
14.
Acta Neurochir (Wien) ; 159(1): 15-18, 2017 01.
Artículo en Inglés | MEDLINE | ID: mdl-27812816

RESUMEN

Cerebral amyloid angiopathy (CAA), a cause of recurrent and multiple lobar hemorrhages, characteristically occurs in persons aged ≥55 years. We report a case of a 32-year-old male who had recurrent hemorrhage in the left multiple lobes, with a history of traumatic brain injury and hematoma evacuation at the age of 1 year. He underwent surgical treatment and was histopathologically diagnosed as having CAA. The literature review yielded six CAA cases, including ours, aged less than 55 years. All were male and four had histories of severe TBI, suggesting that male sex and TBI may be associated with CAA in young persons.


Asunto(s)
Lesiones Traumáticas del Encéfalo/complicaciones , Angiopatía Amiloide Cerebral/etiología , Hemorragia Cerebral/etiología , Adulto , Angiopatía Amiloide Cerebral/complicaciones , Humanos , Masculino
15.
Artif Life ; 14(1): 29-48, 2008.
Artículo en Inglés | MEDLINE | ID: mdl-18171129

RESUMEN

The circadian clock of Drosophila is a model pathway for research in biological clock mechanisms, both with traditional experimental approaches and with emerging systems biology approaches utilizing mathematical modeling and in silico computer simulation. Dynamic diurnal oscillations are achieved by the complex interaction of components as a system, and mathematical reconstruction has proven to be an invaluable means of understanding such systematic behavior. In this study, we implemented eight published models of the Drosophila circadian clock in Systems Biology Markup Language (SBML) for comparative systems biology studies using E-Cell Simulation Environment version 3, to examine the system-level requirements for the clock mechanism to be robust, by calculating the period and amplitude sensitivity coefficients with simulation experiments. While all models were generally robust as determined by the network topology of the oscillatory feedback loop structure, existing models place relatively strong emphasis on transcription regulation, although this is a limitation on robustness. We suggest that more comprehensive modeling including protein phosphorylation, polymerization, and nuclear transport with regard to amplitude sensitivity will be necessary for understanding the light entrainment and temperature compensation of circadian clocks.


Asunto(s)
Relojes Biológicos/fisiología , Ritmo Circadiano/fisiología , Simulación por Computador , Drosophila/fisiología , Modelos Biológicos , Animales , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Regulación de la Expresión Génica , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Programas Informáticos
16.
Chirality ; 20(3-4): 282-7, 2008 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-17597116

RESUMEN

The partial resolution is described of a series of racemic trans-4-[5-(4-alkoxyphenyl)-2,5-dimethylpyrrolidine-1-oxyl-2-yl]benzoic acids (1), which are the key intermediates for the synthesis of chiral organic radical liquid crystalline compounds and are crystallized to give racemic compounds. Racemic acid 1 [(+/-)-1] with a long alkyl chain (C7 to C13) could be resolved by the conventional diastereomeric salt formation using (R)- or (S)-1-phenylethylamine (2) as the resolving agent, whereas resolution of (+/-)-1 with a short alkyl chain (C4 to C6) was unsuccessful. Use of six equiv of (R)- or (S)-2 for the initial diastereomeric salt formation of (+/-)-1 with a C7-C13 alkyl chain, followed by recrystallization of the resulting salts once or twice, gave 2S,5S- or 2R,5R-enriched 1, respectively, in an ee range of 75-92% and with an overall recovery of 11-27%, based on the original quantity of (+/-)-1.

17.
FEBS J ; 274(6): 1449-58, 2007 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-17489100

RESUMEN

Methemoglobin (metHb), an oxidized form of hemoglobin, is unable to bind and carry oxygen. Erythrocytes are continuously subjected to oxidative stress and nitrite exposure, which results in the spontaneous formation of metHb. To avoid the accumulation of metHb, reductive pathways mediated by cytochrome b5 or flavin, coupled with NADH-dependent or NADPH-dependent metHb reductases, respectively, keep the level of metHb in erythrocytes at less than 1% of the total hemoglobin under normal conditions. In this work, a mathematical model has been developed to quantitatively assess the relative contributions of the two major metHb-reducing pathways, taking into consideration the supply of NADH and NADPH from central energy metabolism. The results of the simulation experiments suggest that these pathways have different roles in the reduction of metHb; one has a high response rate to hemoglobin oxidation with a limited reducing flux, and the other has a low response rate with a high capacity flux. On the basis of the results of our model, under normal oxidative conditions, the NADPH-dependent system, the physiological role of which to date has been unclear, is predicted to be responsible for most of the reduction of metHb. In contrast, the cytochrome b5-NADH pathway becomes dominant under conditions of excess metHb accumulation, only after the capacity of the flavin-NADPH pathway has reached its limit. We discuss the potential implications of a system designed with two metHb-reducing pathways in human erythrocytes.


Asunto(s)
Adaptación Fisiológica , Eritrocitos/metabolismo , Metahemoglobina/metabolismo , Estrés Oxidativo , Humanos , Oxidación-Reducción
18.
Theor Biol Med Model ; 4: 19, 2007 May 20.
Artículo en Inglés | MEDLINE | ID: mdl-17511884

RESUMEN

BACKGROUND: In the process of constructing a dynamic model of a metabolic pathway, a large number of parameters such as kinetic constants and initial metabolite concentrations are required. However, in many cases, experimental determination of these parameters is time-consuming. Therefore, for large-scale modelling, it is essential to develop a method that requires few experimental parameters. The hybrid dynamic/static (HDS) method is a combination of the conventional kinetic representation and metabolic flux analysis (MFA). Since no kinetic information is required in the static module, which consists of MFA, the HDS method may dramatically reduce the number of required parameters. However, no adequate method for developing a hybrid model from experimental data has been proposed. RESULTS: In this study, we develop a method for constructing hybrid models based on metabolome data. The method discriminates enzymes into static modules and dynamic modules using metabolite concentration time series data. Enzyme reaction rate time series were estimated from the metabolite concentration time series data and used to distinguish enzymes optimally for the dynamic and static modules. The method was applied to build hybrid models of two microbial central-carbon metabolism systems using simulation results from their dynamic models. CONCLUSION: A protocol to build a hybrid model using metabolome data and a minimal number of kinetic parameters has been developed. The proposed method was successfully applied to the strictly regulated central-carbon metabolism system, demonstrating the practical use of the HDS method, which is designed for computer modelling of metabolic systems.


Asunto(s)
Enzimas/metabolismo , Escherichia coli/enzimología , Metabolismo , Saccharomyces cerevisiae/enzimología , Proteínas de Escherichia coli/metabolismo , Cinética , Modelos Biológicos , Reproducibilidad de los Resultados , Proteínas de Saccharomyces cerevisiae/metabolismo
19.
Science ; 316(5824): 593-7, 2007 Apr 27.
Artículo en Inglés | MEDLINE | ID: mdl-17379776

RESUMEN

Analysis of cellular components at multiple levels of biological information can provide valuable functional insights. We performed multiple high-throughput measurements to study the response of Escherichia coli cells to genetic and environmental perturbations. Analysis of metabolic enzyme gene disruptants revealed unexpectedly small changes in messenger RNA and proteins for most disruptants. Overall, metabolite levels were also stable, reflecting the rerouting of fluxes in the metabolic network. In contrast, E. coli actively regulated enzyme levels to maintain a stable metabolic state in response to changes in growth rate. E. coli thus seems to use complementary strategies that result in a metabolic network robust against perturbations.


Asunto(s)
Proteínas de Escherichia coli/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Genes Bacterianos , Redes y Vías Metabólicas , Biología de Sistemas/métodos , Cromatografía Liquida , Biología Computacional , Electroforesis Capilar , Electroforesis en Gel Bidimensional , Inducción Enzimática , Represión Enzimática , Enzimas/genética , Enzimas/metabolismo , Escherichia coli/enzimología , Escherichia coli/crecimiento & desarrollo , Proteínas de Escherichia coli/genética , Expresión Génica , Espectrometría de Masas , Redes y Vías Metabólicas/genética , Mutación , Análisis de Secuencia por Matrices de Oligonucleótidos , Proteoma , ARN Mensajero/genética , ARN Mensajero/metabolismo , Transcripción Genética
20.
Gene ; 392(1-2): 239-46, 2007 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-17270364

RESUMEN

Chi sites (5'-GCTGGTGG-3') are homologous recombinational hotspot octamer sequences, which attenuate the exonuclease activity of RecBCD in Escherichia coli. They are overrepresented in the genome (1008 occurrences), preferentially located within coding regions (98%), oriented in the direction of replication (75%), and occur most commonly on the mRNA-synonymous sense strand of the double helix (79%). Previous statistical studies of the genome sequence suggested that these genomic properties of Chi sites appear to be related to their role in recombinational repair and therefore to replication and transcription. In this study, we employ three mathematical models to predict the properties of Chi sites from single nucleotide and multi-nucleotide compositions, and validate them statistically using the distribution of all octamer sequences in the entire genome, or exclusively within ORFs. The model based on the overall distribution of all octamers provided better predictions than the single nucleotide composition model, and the ORF and sense strand preference of Chi sites were shown to be within the standard deviation of all octamers. In contrast, the orientation bias of the Chi sites in the direction of replication was significant, although the bias was not as pronounced as with the single nucleotide composition model, suggesting a selective pressure related to the role of RecBCD in replication.


Asunto(s)
Mapeo Cromosómico , Escherichia coli/genética , Marcadores Genéticos , Replicación del ADN , Modelos Teóricos , Sistemas de Lectura Abierta , ARN Mensajero/genética , Recombinación Genética/genética , Distribuciones Estadísticas
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