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1.
Nature ; 628(8006): 195-203, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38480879

RESUMO

Sustained smouldering, or low-grade activation, of myeloid cells is a common hallmark of several chronic neurological diseases, including multiple sclerosis1. Distinct metabolic and mitochondrial features guide the activation and the diverse functional states of myeloid cells2. However, how these metabolic features act to perpetuate inflammation of the central nervous system is unclear. Here, using a multiomics approach, we identify a molecular signature that sustains the activation of microglia through mitochondrial complex I activity driving reverse electron transport and the production of reactive oxygen species. Mechanistically, blocking complex I in pro-inflammatory microglia protects the central nervous system against neurotoxic damage and improves functional outcomes in an animal disease model in vivo. Complex I activity in microglia is a potential therapeutic target to foster neuroprotection in chronic inflammatory disorders of the central nervous system3.


Assuntos
Complexo I de Transporte de Elétrons , Inflamação , Microglia , Doenças Neuroinflamatórias , Animais , Feminino , Humanos , Masculino , Camundongos , Sistema Nervoso Central/efeitos dos fármacos , Sistema Nervoso Central/metabolismo , Sistema Nervoso Central/patologia , Modelos Animais de Doenças , Transporte de Elétrons/efeitos dos fármacos , Complexo I de Transporte de Elétrons/antagonistas & inibidores , Complexo I de Transporte de Elétrons/metabolismo , Inflamação/tratamento farmacológico , Inflamação/metabolismo , Inflamação/patologia , Microglia/efeitos dos fármacos , Microglia/metabolismo , Microglia/patologia , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Mitocôndrias/patologia , Multiômica , Células Mieloides/metabolismo , Células Mieloides/patologia , Doenças Neuroinflamatórias/tratamento farmacológico , Doenças Neuroinflamatórias/metabolismo , Doenças Neuroinflamatórias/patologia , Espécies Reativas de Oxigênio/metabolismo
2.
Eur J Neurol ; 22(1): 142-9, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25142748

RESUMO

BACKGROUND AND PURPOSE: Earlier studies suggested an association between idiopathic restless legs syndrome (RLS) and cardiovascular diseases. However, the risk of cardiovascular events in patients with secondary RLS due to end-stage renal disease (ESRD) is unclear. Our aim was to examine whether ESRD patients with RLS had an increased risk of cardio/cerebrovascular events and mortality. METHODS: In all, 1093 ESRD patients were recruited between 2009 and 2010. The diagnosis and severity of RLS were assessed in a face-to-face interview. The occurrence of cardio/cerebrovascular events and death were confirmed by medical record review. The association between RLS and the outcomes of interest was examined using an adjusted multivariate Cox regression model. RESULTS: After a mean follow-up period of 3.7 ± 0.8 years, ESRD patients with RLS had a significantly higher risk of developing cardiovascular events and strokes [adjusted hazard ratio (aHR) 2.82, 95% confidence interval (CI) 2.02-4.11, and aHR 2.41, 95% CI 1.55-3.75, respectively] compared with patients without RLS. Increasing RLS severity was associated with an increasing likelihood of cardiovascular events [mild RLS severity, aHR 1.71 (95% CI 1.02-2.87); moderate, 2.79 (1.64-4.66); severe, 2.85 (1.99-4.46)] and strokes [mild, 1.89 (0.87-4.16); moderate, 2.42 (1.50-3.90); severe, 2.64 (1.49-4.91)] in a dose-dependent manner. RLS also increased the risk of total mortality in patients with ESRD [aHR 1.53 (95% CI 1.07-2.18), P = 0.02]; this association attenuated slightly after stratification by individual RLS severity category [mild RLS severity, aHR 1.44 (95% CI 0.78-2.67); moderate, 1.49 (0.98-2.55); severe, 2.03 (0.93-4.45)]. CONCLUSIONS: ESRD patients with RLS demonstrated an increased likelihood of cardio/cerebrovascular events and mortality.


Assuntos
Doenças Cardiovasculares/epidemiologia , Falência Renal Crônica/epidemiologia , Síndrome das Pernas Inquietas/epidemiologia , Idoso , Doenças Cardiovasculares/mortalidade , Transtornos Cerebrovasculares/epidemiologia , Transtornos Cerebrovasculares/mortalidade , Comorbidade , Feminino , Humanos , Falência Renal Crônica/complicações , Masculino , Pessoa de Meia-Idade , Síndrome das Pernas Inquietas/etiologia , Índice de Gravidade de Doença
3.
Curr Oncol ; 22(4): 287-96, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26300667

RESUMO

OBJECTIVE: The purpose of this guideline is to help ensure the provision of high-quality colposcopy practices in the province of Ontario, including those conducted as diagnostic procedures in follow-up to an abnormal cervical screening test. METHODS: This document updates the recommendations published in the 2008 colposcopy guideline from Cancer Care Ontario, The Optimum Organization for the Delivery of Colposcopy Service in Ontario. A systematic review of guidelines was conducted to evaluate the existing evidence and recommendations concerning these key aspects of colposcopy: □ Training, qualification, accreditation, and maintenance of competence□ Practice setting requirements□ Operational practice□ Quality indicators and outcomes. RESULTS: This guideline provides recommendations on training and maintenance of competence for colposcopists in the practice settings in which colposcopic evaluation and treatments are conducted. It also provides recommendations on operational issues and quality indicators for colposcopy. CONCLUSIONS: This updated guideline is intended to support quality improvement for colposcopy for all indications, including the follow-up of an abnormal cervical screening test and work-up for lower genital tract lesions that are not clearly malignant. The recommendations contained in this document are intended for clinicians and institutions performing colposcopy in Ontario, and for policymakers and program planners involved in the delivery of colposcopy services.

4.
Eur J Neurol ; 21(3): 492-8, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24433515

RESUMO

BACKGROUND AND PURPOSE: Recent genome-wide association studies have shown associations between multiple genetic variants and primary restless legs syndrome (RLS). Their roles in end stage renal disease (ESRD) related secondary RLS are not clear and studies in Asian populations are scarce. The association between candidate genetic variants and uremic RLS was investigated in a large cohort of Taiwanese dialysis patients. METHODS: Sixteen RLS-related genetic variants at six loci, including MEIS1, BTBD9, MAP2K5/SKOR1, PTPRD, TOX3/BC034767 and the intergenic region of chromosome 2p14, in a total of 993 ESRD patients (259 subjects with and 734 subjects without RLS) were genotyped using TaqMan genotyping assays. Multivariate logistic regression analysis was used to test for associations between the genotypes and RLS in ESRD. Power calculations were completed using the CATs Genetic Power Calculator with settings of a multiplicative genetic model. RESULTS: A modest association between the PTPRD variant rs4626664 and uremic RLS (odds ratio 1.52, 95% CI 1.03-2.23, P = 0.03) and a trend that TOX3/BC034767 variant rs3104767 may associate with the occurrence of RLS were observed in our dialysis population (odds ratio 1.74, 95% CI 0.97-3.11, P = 0.06). No associations between other genetic variants and risk and severity of RLS were observed in our ESRD cohort. CONCLUSIONS: The genetic variants of primary RLS candidate genes did not play a major role in our uremic RLS populations. The ethnic difference and heterogeneous etiologies underlying renal failure may partly explain the minor genetic contribution to uremic RLS in our populations. Further studies for other ethnicities will be of worth.


Assuntos
Variação Genética/genética , Falência Renal Crônica/complicações , Proteínas Tirosina Fosfatases Classe 2 Semelhantes a Receptores/genética , Receptores de Progesterona/genética , Síndrome das Pernas Inquietas/etiologia , Síndrome das Pernas Inquietas/genética , Idoso , Proteínas Reguladoras de Apoptose , Cromossomos Humanos Par 2/genética , Feminino , Estudos de Associação Genética , Genótipo , Proteínas de Grupo de Alta Mobilidade , Humanos , Falência Renal Crônica/genética , Desequilíbrio de Ligação , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Taiwan/epidemiologia , Transativadores
5.
bioRxiv ; 2024 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-38260262

RESUMO

Sustained smouldering, or low grade, activation of myeloid cells is a common hallmark of several chronic neurological diseases, including multiple sclerosis (MS) 1 . Distinct metabolic and mitochondrial features guide the activation and the diverse functional states of myeloid cells 2 . However, how these metabolic features act to perpetuate neuroinflammation is currently unknown. Using a multiomics approach, we identified a new molecular signature that perpetuates the activation of myeloid cells through mitochondrial complex II (CII) and I (CI) activity driving reverse electron transport (RET) and the production of reactive oxygen species (ROS). Blocking RET in pro-inflammatory myeloid cells protected the central nervous system (CNS) against neurotoxic damage and improved functional outcomes in animal disease models in vivo . Our data show that RET in myeloid cells is a potential new therapeutic target to foster neuroprotection in smouldering inflammatory CNS disorders 3 .

6.
Eur J Neurol ; 20(7): 1025-31, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23369046

RESUMO

BACKGROUND AND PURPOSE: Restless legs syndrome (RLS) is an underestimated movement disorder in patients with end-stage renal disease (ESRD). Several clinical and laboratory factors were inconsistently reported to associate with RLS. We aim to perform a large-scale multicenter study to investigate the possible associated risk factors of RLS in patients with ESRD in Taiwan, a country with the highest incidence of uremia in the world. METHODS: From October 2009 to October 2011, we constitutively recruited 1130 patients with ESRD from 17 hemodialysis centers. Demographic, laboratory data, presence and severity of RLS were collected. Odds ratios (ORs) were estimated by logistic regression models. RESULTS: We found the prevalence of RLS to be 25.3% in patients with ESRD. Having type 2 diabetes [OR = 3.61 (2.27-5.77), P < 0.01], low serum transferrin saturation [OR = 1.42 (1.01-2.03), P < 0.05] and duration of dialysis [OR = 1.09 (1.03-1.14), P < 0.01] were associated with RLS. In contrast, high serum hemoglobin level was inversely associated with RLS [OR = 0.61 (0.40-0.89), P < 0.05]. RLS has a significant impact on sleep quality in dialysis patients. Among patients with RLS, history of type 2 diabetes [OR = 4.04 (1.65-10.79), P < 0.05], low serum hemoglobin level [OR = 5.41 (2.43-13.12), P < 0.01] and duration of dialysis [OR = 1.01 (1.01-1.02), P < 0.01] were associated with increased severity of RLS. CONCLUSIONS: Our findings demonstrated that RLS is common in Taiwanese dialysis patients. Clinicians should have a high suspicion for the presence of RLS symptoms in patients with ESRD, especially those with type 2 diabetes, anemia, low serum iron status and long duration of dialysis.


Assuntos
Falência Renal Crônica/epidemiologia , Síndrome das Pernas Inquietas/epidemiologia , Feminino , Humanos , Falência Renal Crônica/complicações , Masculino , Pessoa de Meia-Idade , Prevalência , Diálise Renal/estatística & dados numéricos , Síndrome das Pernas Inquietas/complicações , Fatores de Risco , Taiwan/epidemiologia
7.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 2003-2006, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018396

RESUMO

Breast-conserving surgery, also known as lumpectomy, is an early stage breast cancer treatment that aims to spare as much healthy breast tissue as possible. A risk associated with lumpectomy is the presence of cancer positive margins post operation. Surgical navigation has been shown to reduce cancer positive margins but requires manual segmentation of the tumor intraoperatively. In this paper, we propose an end-to-end solution for automatic contouring of breast tumor from intraoperative ultrasound images using two convolutional neural network architectures, the U-Net and residual U-Net. The networks are trained on annotated intraoperative breast ultrasound images and evaluated on the quality of predicted segmentations. This work brings us one step closer to providing surgeons with an automated surgical navigation system that helps reduce cancer-positive margins during lumpectomy.


Assuntos
Neoplasias da Mama , Mastectomia Segmentar , Mama/diagnóstico por imagem , Neoplasias da Mama/diagnóstico por imagem , Feminino , Humanos , Redes Neurais de Computação , Ultrassonografia Mamária
8.
QJM ; 101(1): 13-22, 2008 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-18203722

RESUMO

BACKGROUND: Primary aldosteronism (PA) is a common curable disease of secondary hypertension. Most such patients have either idiopathic bilateral adrenal hyperplasia (BAH) or unilateral aldosterone-producing adenoma (APA). Bilateral APAs are reportedly extremely rare. AIM: To compare the distinctive characteristics, clinical course, and outcomes of bilateral APA vs. BAH. DESIGN: Retrospective record review. METHODS: From July 1994 to Jan 2007, 190 patients diagnosed with PA underwent surgical intervention at our hospital. Bilateral APA was diagnosed in 7/164 patients with histologically-proven APA. Twenty-one patients diagnosed as BAH, and 21 randomly selected of unilateral APA patients, matched by age and sex served as controls. RESULTS: Patients with bilateral APA had similar blood pressure, arterial blood gas analysis, spot urinary potassium to creatinine ratio and clinical symptoms to those with BAH, but lower serum potassium levels (p = 0.027), lower plasma renin activity (p = 0.037), and higher plasma aldosterone concentrations (p = 0.029). Aldosterone-renin ratio (ARR) after administration of 50 mg captopril was higher in bilateral APA than in BAH patients (p = 0.023), but not different between unilateral APA and BAH (p = 0.218). A cut-off of ARR >100 ng/dl per ng/ml/h and plasma aldosterone >20 ng/dl after captopril significantly differentiated bilateral APA from BAH. Bilateral subtotal adrenalectomy normalized blood pressure and biochemistry in all patients with bilateral APA. DISCUSSION: Bilateral APA, presenting simultaneously or sequentially, may not be a rare disease, accounting for 4.3% of APA in this sample. The clinical presentations of bilateral functional adenoma are not different from BAH, but patients with low serum potassium and ARR >100 after captopril should be carefully evaluated for bilateral adenoma.


Assuntos
Adenoma/metabolismo , Neoplasias do Córtex Suprarrenal/metabolismo , Glândulas Suprarrenais/patologia , Aldosterona/biossíntese , Adenoma/diagnóstico por imagem , Adenoma/patologia , Neoplasias do Córtex Suprarrenal/diagnóstico por imagem , Neoplasias do Córtex Suprarrenal/patologia , Glândulas Suprarrenais/metabolismo , Adulto , Idoso , Estudos de Casos e Controles , Feminino , Humanos , Hiperaldosteronismo/metabolismo , Hiperaldosteronismo/patologia , Hiperplasia/metabolismo , Hiperplasia/patologia , Masculino , Pessoa de Meia-Idade , Radiografia , Estudos Retrospectivos
9.
Food Microbiol ; 25(6): 735-44, 2008 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-18620965

RESUMO

The existence of injured microorganisms in food and their recovery during culturing procedures is critical. Microbial injury is characterized by the capability of a microorganism to return to normalcy during a resuscitation process in which the damaged essential components are repaired. Injury of microorganisms can be induced by sublethal heat, freezing, freeze-drying, drying, irradiation, high hydrostatic pressure, aerosolization, dyes, sodium azide, salts, heavy metals, antibiotics, essential oils, sanitizing compounds, and other chemicals or natural antimicrobial compounds. Injured microorganisms present a potential threat in food safety since they may repair themselves under suitable conditions. Detection of injured microorganisms can be important to practical interpretations of data in food microbiology. This review provides an overview of microbial injury in food and discusses the development of recovery methods for detecting injured foodborne microorganisms.


Assuntos
Bactérias/crescimento & desenvolvimento , Qualidade de Produtos para o Consumidor , Contaminação de Alimentos/análise , Microbiologia de Alimentos , Conservação de Alimentos/métodos , Adaptação Fisiológica , Bactérias/patogenicidade , Fenômenos Fisiológicos Bacterianos , Humanos
10.
J Clin Invest ; 95(5): 2338-45, 1995 May.
Artigo em Inglês | MEDLINE | ID: mdl-7738197

RESUMO

Accelerated protein glycation in diabetes has been mechanistically linked to the pathogenesis of diabetic nephropathy. Because glycated albumin induces abnormalities in cultured mesangial cells that resemble those characterizing the glomerular mesangium in diabetes, and monoclonal antibodies (A717) specific for Amadori-modified glycated albumin prevent these abnormalities, we postulated that in vivo administration of A717 could retard the progression of diabetic nephropathy. To test this hypothesis, diabetic db/db mice and their nondiabetic db/m littermates were treated with eight consecutive weekly injections of 150 micrograms of A717 (Fab fragments) to reduce the elevated plasma glycated albumin concentration, or with irrelevant murine IgG (MIg). Relative to nondiabetics, diabetic mice (MIg treated) manifested proteinuria (3.35 +/- 0.15 vs 0.87 +/- 0.1 mg albumin/mg creatinine), 3.8-fold increase in mesangial matrix fraction, and renal cortical overexpression of mRNAs encoding alpha 1(IV) collagen (2.6-fold increase) and fibronectin (3.8-fold increase). Treatment of db/db mice with A717 significantly reduced the proteinuria (1.52 +/- 0.3 mg/mg creatinine), inhibited mesangial matrix expansion, and attenuated overexpression of matrix mRNAs. The nephropathic protective effects of A717 were independent of any change in blood glucose concentrations. Antibodies unreactive with glycated albumin did not duplicate the beneficial effects of A717. Thus, abrogating the biologic effects of increased glycated albumin with A717 has a salutary influence on the pathogenesis of diabetic nephropathy and has novel therapeutic potential in its management.


Assuntos
Anticorpos Monoclonais/uso terapêutico , Nefropatias Diabéticas/prevenção & controle , Fragmentos Fab das Imunoglobulinas/uso terapêutico , Rim/patologia , Albumina Sérica/antagonistas & inibidores , Albuminúria , Animais , Glicemia/metabolismo , Northern Blotting , Peso Corporal , Colágeno/biossíntese , Nefropatias Diabéticas/patologia , Fibronectinas/biossíntese , Expressão Gênica , Mesângio Glomerular/metabolismo , Mesângio Glomerular/patologia , Produtos Finais de Glicação Avançada , Glicosilação , Rim/metabolismo , Córtex Renal/patologia , Glomérulos Renais/metabolismo , Glomérulos Renais/patologia , Camundongos , Camundongos Mutantes , Tamanho do Órgão , Proteinúria , Albumina Sérica/imunologia , Albumina Sérica Glicada
12.
Mucosal Immunol ; 9(3): 777-86, 2016 05.
Artigo em Inglês | MEDLINE | ID: mdl-26462419

RESUMO

Whooping cough is a highly contagious respiratory disease caused by Bordetella pertussis (B. pertussis). T helper 17 (Th17) cells have a central role in the resolution of the infection. Emerging studies document that type I interferons (IFNs) suppress Th17 differentiation and interleukin (IL)-17 responses in models of infection and chronic inflammation. As plasmacytoid dendritic cells (pDCs) are a major source of type I IFNs, we hypothesize that during B. pertussis infection in mice, pDC-derived IFNα inhibits a rapid increase in Th17 cells. We found that IFNα-secreting pDCs appear in the lungs during the early stages of infection, while a robust rise of Th17 cells in the lungs is detected at 15 days post-infection or later. The presence of IFNα led to reduced Th17 differentiation and proliferation in vitro. Furthermore, in vivo blocking of IFNα produced by pDCs during infection with B. pertussis infection resulted in early increase of Th17 frequency, inflammation, and reduced bacterial loads in the airways of infected mice. Taken together, the experiments reported here describe an inhibitory role for pDCs and pDC-derived IFNα in modulating Th17 responses during the early stages of B. pertussis infection, which may explain the prolonged nature of whooping cough.


Assuntos
Bordetella pertussis/imunologia , Células Dendríticas/imunologia , Interferon-alfa/metabolismo , Pulmão/imunologia , Células Th17/imunologia , Coqueluche/imunologia , Animais , Anticorpos Bloqueadores/administração & dosagem , Carga Bacteriana , Diferenciação Celular , Células Cultivadas , Técnicas de Cocultura , Feminino , Humanos , Imunomodulação , Interferon-alfa/imunologia , Pulmão/microbiologia , Ativação Linfocitária , Camundongos , Camundongos Endogâmicos BALB C
13.
Biochim Biophys Acta ; 804(1): 89-99, 1984 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-6539129

RESUMO

We investigated the ability of intracellular ornithine to alter both the biosynthesis of putrescine and the activity of ornithine decarboxylase in Reuber H35 hepatoma cells in culture incubated with 12-O- tetrade - canoylphorbol 13-acetate (TPA). In confluent cultures of H35 cells, the addition of TPA (1.6 microM) caused the activity of ornithine decarboxylase to increase by more than 100-fold within 4 h. When exogenous ornithine (0.1-1.0 mM) was added to the culture medium with TPA, a marked dose-dependent increase in the production of putrescine was observed. The activity of ornithine decarboxylase in the same cultures incubated with ornithine decreased in a similar dose-dependent manner. The addition of arginine (0.1-1.0 mM) (but not lysine or histidine) to the H35 cells in culture concomitant with TPA also led to a relative increase in putrescine biosynthesis and a decrease in ornithine decarboxylase activity compared to cultures not receiving the amino acids. A similar response to exogenous ornithine and TPA was observed in a series of less confluent rapidly growing cultures which were in culture for a shorter period of time. The confluent cultures possessed a basal level of arginase (55 units/mg protein) which increased approx. 2-fold upon treatment with TPA. The intracellular concentration of ornithine in the unstimulated cells was in the order of 0.02-0.03 mM. Upon incubation of the cells with exogenous ornithine or arginine, the intracellular pools of these amino acids increased 4- to 8-fold.


Assuntos
Neoplasias Hepáticas Experimentais/metabolismo , Ornitina Descarboxilase/metabolismo , Ornitina/fisiologia , Putrescina/metabolismo , Animais , Arginase/metabolismo , Arginina/metabolismo , Arginina/farmacologia , Adesão Celular , Células Cultivadas , Relação Dose-Resposta a Droga , Indução Enzimática/efeitos dos fármacos , Acetato de Tetradecanoilforbol/farmacologia
14.
Biochim Biophys Acta ; 797(1): 76-82, 1984 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-6692009

RESUMO

Platelet factor 4, a unique peptide released during platelet aggregation, can bind to natural sulfated glycosaminoglycans from human renal cortex. The glycosaminoglycan isolate contained components sensitive to hyaluronidase, chondroitinase ABC and nitrous acid. Binding was demonstrated by the change in electrophoretic mobility of platelet factor 4 applied in combination with glycosaminoglycan compared to either applied alone. This effect, which occurred at physiologic pH but not at acidic pH or with high ionic strength, was preserved in samples subjected to prior hyaluronidase and chondroitinase digestion. Further demonstration that platelet factor 4 can interact with heparan sulfate anionic sites in the glomerular microvascular matrix was obtained by incubating radiolabeled platelet factor 4 with isolated rat glomeruli, and with purified human and rat glomerular basement membrane, followed by displacement with heparin. Total binding and heparin-released binding were decreased in glomerular basement membrane prepared from diabetic patients and from rats with streptozotocin-diabetes compared to control samples. These findings implicate platelet factor 4 in the pathogenesis of the altered capillary integrity associated with diabetes, and provide novel evidence that heparan sulfate anionic sites in glomerular basement membrane are diminished in human and experimental diabetes.


Assuntos
Diabetes Mellitus/metabolismo , Glicosaminoglicanos/metabolismo , Córtex Renal/análise , Glomérulos Renais/irrigação sanguínea , Fator Plaquetário 4/metabolismo , Animais , Membrana Basal/metabolismo , Capilares/metabolismo , Bovinos , Diabetes Mellitus Experimental/metabolismo , Heparitina Sulfato/metabolismo , Humanos , Ratos
15.
Biochim Biophys Acta ; 938(1): 107-13, 1988 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-3337812

RESUMO

Glycosaminoglycans (GAG) were isolated from bovine retinal microvessel basement membrane (RMV-BM) and quantitatively analyzed using a recently described competitive binding assay that is specific for and sensitive to nanogram amounts of heparan and chondroitin sulfates. Treatment of osmotically lysed retinal microvessels with the ionic detergent deoxycholate (DOC), required for liberation of the extracellular matrix for plasma membrane lipoproteins and purification of the insoluble matrix, solubilized less than 5% of the GAG in the water-insoluble material. Total GAG content in the DOC-insoluble basement membranes was approx. 0.52 micrograms/mg dry weight; about 70% of the measurable GAG was resistant to both chondroitinase ABC and chondroitinase AC digestion and was sensitive to nitrous acid treatment, indicating its heparan sulfate nature. Cellulose acetate electrophoresis revealed two bands, one of which had an electrophoretic mobility similar to heparan sulfate standard and was sensitive to nitrous acid; the other migrated in the same position as chondroitin sulfate standard and was sensitive to chondroitinase ABC and chondroitinase AC digestion. These results provide evidence that RMV-BM contains chondroitin sulfate(s) as well as heparan sulfate, and offer the first quantitative analysis of GAG in this extracellular matrix.


Assuntos
Glicosaminoglicanos/análise , Microcirculação/análise , Retina/irrigação sanguínea , Animais , Membrana Basal/análise , Bovinos , Eletroforese em Acetato de Celulose , Solubilidade
16.
Biochim Biophys Acta ; 678(3): 322-8, 1981 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-7317455

RESUMO

Extraction of rat glomerular basement membrane, purified by osmotic lysis and sequential detergent treatment, with 8 M urea containing protease inhibitors solubilizes protein that is devoid of hydroxyproline and hydroxylysine. This material represents 8-12% of total membrane protein, elutes mainly as two high molecular weight peaks on agarose gel filtration, and is associated with glycosaminoglycans. Isolated rat renal glomeruli incorporate [35S]sulfate into basement membrane from which this non-collagenous 35S-labeled fraction can be subsequently solubilized. The radioactivity incorporated into urea-soluble glomerular basement membrane eluted primarily with the higher molecular weight peak (Mr greater than 250 000). Cellulose acetate electrophoresis after pronase digestion of the urea-soluble fraction revealed glycosaminoglycan that was resistant to digestion with Streptomyces hyaluronidase and chondroitinase ABC, sensitive to nitrous acid treatment, and contained [35S]sulfate. The findings indicate that one of the non-collagenous components of glomerular basement membrane is a proteoglycan containing heparan sulfate.


Assuntos
Glomérulos Renais/metabolismo , Proteínas de Membrana/metabolismo , Proteoglicanas/metabolismo , Aminoácidos/metabolismo , Animais , Membrana Basal/metabolismo , Masculino , Proteínas de Membrana/biossíntese , Peso Molecular , Ratos , Solubilidade , Sulfatos/metabolismo
17.
Biochim Biophys Acta ; 1129(1): 49-56, 1991 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-1684516

RESUMO

The H+/K(+)-ATPase is the dimeric enzyme responsible for H+ secretion by the gastric parietal cells. The present study examined the response of rat fundic mRNA levels of H+/K(+)-ATPase alpha-subunit and somatostatin to the inhibition of H+/K(+)-ATPase enzyme activity and gastric pH elevation by oral omeprazole administration. Omeprazole inhibits the alpha-subunit of H+/K(+)-ATPase covalently and stabilizes stimulated morphology of the parietal cell. After a single administration of omeprazole (100 mg/kg), H+/K(+)-ATPase alpha-subunit mRNA levels increased significantly by 57% at 3 h and remained elevated for 6 h, returning to the basal level by 24 h. After multiple administrations of omeprazole (100 mg/kg per day, every 24 h for 3 days), H+/K(+)-ATPase alpha-subunit mRNA levels were already elevated at the time of the last dose, reached maximum at 6 h (95% increase above control), and returned to the pre-treatment level after 36 h. Nuclear run-on assay indicated H+/K(+)-ATPase gene transcription was significantly increased by omeprazole pretreatment in vivo. In contrast, a significant decrease in fundic somatostatin mRNA occurred at 12 h after a single dose, and the inhibition was more pronounced and lasted longer after multiple doses of omeprazole. These data indicate that omeprazole, while effectively inhibiting H+/K(+)-ATPase activity, induces H+/K(+)-ATPase gene expression in the parietal cells. An inverse relationship exists between the regulation of somatostatin gene expression in fundic D-cells and H+/K(+)-ATPase gene expression. The increase in H+/K(+)-ATPase alpha-subunit mRNA could be due to alterations in extracellular gastrin/somatostatin ratios or could be induced by intracellular effects of omeprazole.


Assuntos
Adenosina Trifosfatases/genética , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Omeprazol/farmacologia , RNA Mensageiro/genética , Somatostatina/genética , Actinas/genética , Animais , Northern Blotting , Gastrinas/sangue , ATPase Trocadora de Hidrogênio-Potássio , Concentração de Íons de Hidrogênio , Cinética , Masculino , Radioimunoensaio , Ratos , Ratos Endogâmicos
18.
Diabetes ; 37(10): 1324-7, 1988 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-2970980

RESUMO

In this study we examined the effect of experimental diabetes and of treatment with an aldose reductase inhibitor on the level of sulfation of glomerular basement membrane (GBM) heparan sulfate, the principal glycosaminoglycan in this extracellular matrix. Glycosaminoglycans were isolated from GBM purified from control, streptozocin-induced diabetic, and sorbinil-treated diabetic rats and analyzed for sulfate and uronate content. Glomerular yields from diabetic kidneys were greater than those from control animals, but the amount of sulfate per glomerulus in diabetic samples, both untreated and sorbinil treated, did not differ significantly from that in control samples. However, the sulfate-to-uronate ratio in heparan sulfate isolated from diabetic GBM (0.34 +/- 0.08) was significantly less than in control samples (0.69 +/- 0.11), and treatment of diabetic rats with an aldose reductase inhibitor did not correct this reduced ratio (0.36 +/- 0.06). The results indicate that there is an undersulfation of heparan sulfate of GBM in experimental diabetes, an abnormality that may contribute to loss of anionic sites and decreased charge selectivity of the glomerular filtration barrier. The findings further suggest that this abnormality results from disturbances in glycosaminoglycan synthesis and/or metabolism in diabetes that are independent of polyol-pathway activation in the renal glomerulus.


Assuntos
Aldeído Redutase/antagonistas & inibidores , Diabetes Mellitus Experimental/metabolismo , Glicosaminoglicanos/metabolismo , Heparitina Sulfato/metabolismo , Glomérulos Renais/metabolismo , Desidrogenase do Álcool de Açúcar/antagonistas & inibidores , Aldeído Redutase/uso terapêutico , Animais , Membrana Basal/metabolismo , Diabetes Mellitus Experimental/tratamento farmacológico , Matriz Extracelular/metabolismo , Técnicas In Vitro , Masculino , Ratos , Sulfatos/análise
19.
Diabetes ; 36(6): 679-83, 1987 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-3569668

RESUMO

Glycosaminoglycans (GAGs) were purified from basement membranes isolated from glomeruli of control and streptozocin-induced diabetic rats and were quantitatively analyzed with a recently described competitive binding assay that is specific for and sensitive to microgram amounts of chondroitin and heparan sulfate. Total GAG content in glomeruli from diabetic rats and in the basement membranes prepared from these samples (17.22 +/- 1.45 and 6.56 +/- 0.49 micrograms/10(5) glomeruli, respectively was significantly less than that found in comparable control preparations (43.71 +/- 3.35 and 16.05 +/- 1.41 micrograms/10(5) glomeruli, respectively). The portion of total GAG in the water-soluble fraction recovered after osmotic lysis of isolated glomeruli was also markedly decreased in diabetic samples (26.11 +/- 4.55 vs. 3.30 +/- 0.32 micrograms/10(5) glomeruli, control vs. diabetic). Treatment of lysed glomeruli with the ionic detergent deoxycholate, required for liberation of the extracellular matrix from plasma membrane lipoproteins and purification of the insoluble glomerular basement membrane (GBM), resulted in solubilization of approximately 10% of the water-insoluble GAG in control samples but greater than 50% in diabetic membranes. Heparan sulfate comprised greater than 90% of the GAGs in both control and diabetic GBM, defined as the water- and detergent-insoluble matrix. The findings clearly demonstrate that the GAG content of GBM is diminished in experimental diabetes and provide evidence that the reduction in GBM anionic sites associated with diabetes derives from a decrease in the constituent GAGs of this extracellular matrix. The results further suggest that the interaction between GBM and populations of GAG associated with the surface of plasma membranes of adjacent cells is disturbed in diabetes.


Assuntos
Membrana Basal/análise , Diabetes Mellitus Experimental/metabolismo , Glicosaminoglicanos/análise , Glomérulos Renais/análise , Animais , Glicosaminoglicanos/isolamento & purificação , Heparitina Sulfato/análise , Masculino , Ratos
20.
Chem Commun (Camb) ; 51(66): 13138-41, 2015 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-26191546

RESUMO

The as-yet unidentified E. coli metabolite colibactin induces DNA damage in eukaryotic cells and promotes tumorigenesis. Its wide distribution in pathogenic and probiotic strains has raised great interest in its structure and biosynthesis. Here we show that colibactin formation involves a rare aminomalonyl unit used as a building block.


Assuntos
Escherichia coli/metabolismo , Peptídeos/química , Peptídeos/metabolismo , Policetídeos/química , Policetídeos/metabolismo , Escherichia coli/genética , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Mutação
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