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1.
Front Cell Dev Biol ; 11: 1271201, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-38078004

RESUMEN

Introduction: In light of the impact of airway barrier leaks in COVID-19 and the significance of vitamin D in COVID-19 outcomes, including airway barrier protection, we investigated whether the very common dietary flavonoid quercetin could also be efficacious in supporting airway barrier function. Methods: To address this question, we utilized the widely used airway epithelial cell culture model, Calu-3. Results: We observed that treating Calu-3 cell layers with quercetin increased transepithelial electrical resistance while simultaneously reducing transepithelial leaks of 14C-D-mannitol (Jm) and 14C-inulin. The effects of quercetin were concentration-dependent and exhibited a biphasic time course. These effects of quercetin occurred with changes in tight junctional protein composition as well as a partial inhibition of cell replication that resulted in decreased linear junctional density. Both of these effects potentially contribute to improved barrier function. Quercetin was equally effective in reducing the barrier compromise caused by the pro-inflammatory cytokine TNF-α, an action that seemed to derive, in part, from reducing the elevation of ERK 1/2 caused by TNF-α. Discussion: Quercetin improved Calu-3 barrier function and reduced TNF-α-induced barrier compromise, mediated in part by changes in the tight junctional complex.

2.
Dig Dis Sci ; 66(4): 1195-1211, 2021 04.
Artículo en Inglés | MEDLINE | ID: mdl-32415564

RESUMEN

BACKGROUND: Chemopreventive effects of zinc for esophageal cancer have been well documented in animal models. This prospective study explores if a similar, potentially chemopreventive action can be seen in Barrett's esophagus (BE) in humans. AIMS: To determine if molecular evidence can be obtained potentially indicating zinc's chemopreventive action in Barrett's metaplasia. METHODS: Patients with a prior BE diagnosis were placed on oral zinc gluconate (14 days of 26.4 mg zinc BID) or a sodium gluconate placebo, prior to their surveillance endoscopy procedure. Biopsies of Barrett's mucosa were then obtained for miRNA and mRNA microarrays, or protein analyses. RESULTS: Zinc-induced mRNA changes were observed for a large number of transcripts. These included downregulation of transcripts encoding proinflammatory proteins (IL32, IL1ß, IL15, IL7R, IL2R, IL15R, IL3R), upregulation of anti-inflammatory mediators (IL1RA), downregulation of transcripts mediating epithelial-to-mesenchymal transition (EMT) (LIF, MYB, LYN, MTA1, SRC, SNAIL1, and TWIST1), and upregulation of transcripts that oppose EMT (BMP7, MTSS1, TRIB3, GRHL1). miRNA arrays showed significant upregulation of seven miRs with tumor suppressor activity (-125b-5P, -132-3P, -548z, -551a, -504, -518, and -34a-5P). Of proteins analyzed by Western blot, increased expression of the pro-apoptotic protein, BAX, and the tight junctional protein, CLAUDIN-7, along with decreased expression of BCL-2 and VEGF-R2 were noteworthy. CONCLUSIONS: When these mRNA, miRNA, and protein molecular data are considered collectively, a cancer chemopreventive action by zinc in Barrett's metaplasia may be possible for this precancerous esophageal tissue. These results and the extensive prior animal model studies argue for a future prospective clinical trial for this safe, easily-administered, and inexpensive micronutrient, that could determine if a chemopreventive action truly exists.


Asunto(s)
Antineoplásicos/administración & dosificación , Esófago de Barrett/tratamiento farmacológico , Esófago de Barrett/genética , Gluconatos/administración & dosificación , Análisis de Secuencia de ARN/métodos , Administración Oral , Adulto , Anciano , Esófago de Barrett/diagnóstico , Quimioprevención/métodos , Neoplasias Esofágicas/diagnóstico , Neoplasias Esofágicas/genética , Neoplasias Esofágicas/prevención & control , Femenino , Humanos , Masculino , MicroARNs/genética , Persona de Mediana Edad , Proyectos Piloto , Lesiones Precancerosas/diagnóstico , Lesiones Precancerosas/genética , Lesiones Precancerosas/prevención & control , Estudios Prospectivos
3.
Infect Immun ; 88(5)2020 04 20.
Artículo en Inglés | MEDLINE | ID: mdl-32122940

RESUMEN

Bovine digital dermatitis (BDD), an infectious disease of the bovine foot with a predominant treponemal etiology, is a leading cause of lameness in dairy and beef herds worldwide. BDD is poorly responsive to antimicrobial therapy and exhibits a relapsing clinical course; an effective vaccine is therefore urgently sought. Using a reverse vaccinology approach, the present study surveyed the genomes of the three BDD-associated Treponema phylogroups for putative ß-barrel outer membrane proteins and considered their potential as vaccine candidates. Selection criteria included the presence of a signal peptidase I cleavage site, a predicted ß-barrel fold, and cross-phylogroup homology. Four candidate genes were overexpressed in Escherichia coli BL21(DE3), refolded, and purified. Consistent with their classification as ß-barrel OMPs, circular-dichroism spectroscopy revealed the adoption of a predominantly ß-sheet secondary structure. These recombinant proteins, when screened for their ability to adhere to immobilized extracellular matrix (ECM) components, exhibited a diverse range of ligand specificities. All four proteins specifically and dose dependently adhered to bovine fibrinogen. One recombinant protein was identified as a candidate diagnostic antigen (disease specificity, 75%). Finally, when adjuvanted with aluminum hydroxide and administered to BDD-naive calves using a prime-boost vaccination protocol, these proteins were immunogenic, eliciting specific IgG antibodies. In summary, we present the description of four putative treponemal ß-barrel OMPs that exhibit the characteristics of multispecific adhesins. The observed interactions with fibrinogen may be critical to host colonization and it is hypothesized that vaccination-induced antibody blockade of these interactions will impede treponemal virulence and thus be of therapeutic value.


Asunto(s)
Formación de Anticuerpos/inmunología , Proteínas de la Membrana Bacteriana Externa/metabolismo , Dermatitis Digital/inmunología , Dermatitis Digital/microbiología , Treponema/inmunología , Treponema/patogenicidad , Adhesinas Bacterianas/metabolismo , Animales , Adhesión Bacteriana/fisiología , Bovinos , Enfermedades de los Bovinos/inmunología , Enfermedades de los Bovinos/microbiología , ADN Bacteriano/genética , Escherichia coli/inmunología , Escherichia coli/metabolismo , Matriz Extracelular/metabolismo , Matriz Extracelular/microbiología , Inmunoglobulina G/metabolismo , Proteínas de la Membrana/metabolismo , Filogenia , Conformación Proteica en Lámina beta , Serina Endopeptidasas/metabolismo , Virulencia/fisiología
4.
J Magn Reson Imaging ; 50(2): 529-540, 2019 08.
Artículo en Inglés | MEDLINE | ID: mdl-30569620

RESUMEN

BACKGROUND: Conventional MRI fails to detect regions of glioblastoma cell infiltration beyond the contrast-enhanced T1 solid tumor region, with infiltrating tumor cells often migrating along host blood vessels. PURPOSE: To quantitatively and qualitatively analyze the correlation between perfusion MRI signal and tumor cell density in order to assess whether local perfusion perturbation could provide a useful biomarker of glioblastoma cell infiltration. STUDY TYPE: Animal model. SUBJECTS: Mice bearing orthotopic glioblastoma xenografts generated from a patient-derived glioblastoma cell line. FIELD STRENGTH/SEQUENCES: 7T perfusion images acquired using a high signal-to-noise ratio (SNR) multiple boli arterial spin labeling sequence were compared with conventional MRI (T1 /T2 weighted, contrast-enhanced T1 , diffusion-weighted, and apparent diffusion coefficient). ASSESSMENT: Immunohistochemistry sections were stained for human leukocyte antigen (probing human-derived tumor cells). To achieve quantitative MRI-tissue comparison, multiple histological slices cut in the MRI plane were stacked to produce tumor cell density maps acting as a "ground truth." STATISTICAL TESTS: Sensitivity, specificity, accuracy, and Dice similarity indices were calculated and a two-tailed, paired t-test used for statistical analysis. RESULTS: High comparison test results (Dice 0.62-0.72, Accuracy 0.86-0.88, Sensitivity 0.51-0.7, and Specificity 0.92-0.97) indicate a good segmentation for all imaging modalities and highlight the quality of the MRI tissue assessment protocol. Perfusion imaging exhibits higher sensitivity (0.7) than conventional MRI (0.51-0.61). MRI/histology voxel-to-voxel comparison revealed a negative correlation between tumor cell infiltration and perfusion at the tumor margins (P = 0.0004). DATA CONCLUSION: These results demonstrate the ability of perfusion imaging to probe regions of low tumor cell infiltration while confirming the sensitivity limitations of conventional imaging modalities. The quantitative relationship between tumor cell density and perfusion identified in and beyond the edematous T2 hyperintensity region surrounding macroscopic tumor could be used to detect marginal tumor cell infiltration with greater accuracy. LEVEL OF EVIDENCE: 1 Technical stage: 2 J. Magn. Reson. Imaging 2019;50:529-540.


Asunto(s)
Edema/diagnóstico por imagen , Glioblastoma/diagnóstico por imagen , Imagen por Resonancia Magnética , Neoplasias/diagnóstico por imagen , Animales , Medios de Contraste , Modelos Animales de Enfermedad , Humanos , Procesamiento de Imagen Asistido por Computador , Inmunohistoquímica , Ratones , Ratones Desnudos , Trasplante de Neoplasias , Perfusión , Reproducibilidad de los Resultados
5.
BMC Gastroenterol ; 18(1): 2, 2018 Jan 05.
Artículo en Inglés | MEDLINE | ID: mdl-29304733

RESUMEN

BACKGROUND: Elevation of the transcription factor HIF-1 is a prominent mediator of not only processes that accompany hypoxia, but also the tumor microenvironment and tissue regeneration. This study uses mediators of "chemical hypoxia" to ask the question whether HIF-1α elevation in a healthy epithelial cell layer leads to leakiness in its tight junctional seals. METHODS: Transepithelial electrical resistance and transepithelial diffusion of 14C-D-mannitol and other radiolabeled probes are used as indicators of transepithelial barrier function of CaCo-2 BBe human gastrointestinal epithelial cell layers cultured on permeable supports. Western immunoblot analyses of integral tight junctional proteins (occludin and claudins) are used as further indicators of barrier function change. RESULTS: Cobalt, an inhibitor of the prolyl hydroxylase enzymes governing HIF-1α breakdown in the cell, induces transepithelial leakiness in CaCo-2 BBe cell layers in a time and concentration-dependent manner. This increased leakiness is accompanied by significant changes in certain specific integral tight junctional (TJ) proteins such as a decreased level of occludin and increased level of claudin-5. Similar results regarding barrier function compromise also occur with other chemical inhibitors of HIF-1α breakdown, namely ciclopiroxolamine (CPX) and dimethyloxalylglycine (DMOG). The increased leak is manifested by both decreased transepithelial electrical resistance (Rt) and increased paracellular diffusion of D-mannitol (Jm). The induced transepithelial leak shows significant size selectivity, consistent with induced effects on TJ permeability. Less-differentiated cell layers were significantly more affected than well-differentiated cell layers regarding induced transepithelial leak. A genetically modified CaCo-2 variant with reduced levels of HIF-1ß, showed reduced transepithelial leak in response to cobalt exposure, further indicating that elevation of HIF-1α levels induced by agents of "chemical hypoxia" is responsible for the compromised barrier function of the CaCo-2 BBe cell layers. CONCLUSIONS: Exposure to inducers of chemical hypoxia elevated HIF-1α levels and increased transepithelial leak. The degree of epithelial differentiation has significant effects on this action, possibly explaining the varying effects of HIF-1 modulation in epithelial and endothelial barrier function in different physiological and pathophysiological conditions.


Asunto(s)
Cobalto/farmacología , Tracto Gastrointestinal/citología , Tracto Gastrointestinal/efectos de los fármacos , Subunidad alfa del Factor 1 Inducible por Hipoxia/metabolismo , Uniones Estrechas/efectos de los fármacos , Células CACO-2 , Claudinas/metabolismo , Tracto Gastrointestinal/metabolismo , Humanos , Ocludina/metabolismo , Permeabilidad/efectos de los fármacos , Uniones Estrechas/metabolismo
7.
Dig Dis Sci ; 55(5): 1255-63, 2010 May.
Artículo en Inglés | MEDLINE | ID: mdl-19513837

RESUMEN

Previous animal and patient-based studies have shown that omeprazole induces a transepithelial paracellular gastric leak. This study reports on the potential for an omeprazole-induced leak of drugs with narrow therapeutic windows. Ussing chamber experiments investigated the effects of omeprazole on rat gastric corpus permeability to the drugs, digoxin and phenytoin. Digoxin (780 MW) permeated the gastric mucosa at an accelerated rate in the presence of omeprazole. This leak could contribute to dangerous elevations of blood digoxin levels in certain situations. Omeprazole was found to have no effect on the flux rate of phenytoin (252 MW). The tight-junctional leak generated by omeprazole thus exhibits specificity to the types of molecules it allows to permeate through the gastric mucosa. This leak may pose a clinical danger by increasing drug uptake into the bloodstream, a phenomenon which would act synergistically with the effect of omeprazole on inhibiting liver cytochrome P450s that remove drugs from the bloodstream, thereby elevating drug blood levels.


Asunto(s)
Digoxina/farmacología , Mucosa Gástrica/efectos de los fármacos , Omeprazol/farmacología , Inhibidores de la Bomba de Protones/farmacología , Uniones Estrechas/efectos de los fármacos , Animales , Cromatografía en Capa Delgada , Electrofisiología , Concentración de Iones de Hidrógeno , Técnicas In Vitro , Masculino , Permeabilidad , Fenitoína/farmacología , Ratas , Ratas Sprague-Dawley
8.
Aliment Pharmacol Ther ; 28(11-12): 1317-25, 2008 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-18684245

RESUMEN

BACKGROUND: Proton pump inhibitors (PPIs) are one of the most widely used drug classes in the US and are now frontline medications for gastro-oesophageal reflux disease (GERD) and dyspepsia. In a previous work, we observed that a transmucosal, upper gastrointestinal (GI) leak exists in Barrett's oesophagus (BO) patients. PPI medications are commonly used by Barrett's patients. AIM: To examine if the PPI, esomeprazole, affects the barrier function of the upper GI tract. METHODS: The sucrose permeability test (SPT) was used to assess the possible effect of the PPI, esomeprazole, on upper GI leak in 37 first-time-presenting GERD patients and 25 healthy controls. RESULTS: Esomeprazole induced a significant transmucosal leak in the upper GI tract of patients taking the drug for the first time. The leak occurred quickly, within days of first taking the drug. The leak was also reversed within days of stopping the medication. CONCLUSIONS: This is the first patient-based study showing that a PPI compromises upper GI barrier function. There are potential implications for transmucosal leak of other medications that a patient on a PPI may be taking, as well as possible leak of endogenous peptides/proteins. The clinical consequences of this phenomenon are currently unknown, but are potentially important.


Asunto(s)
Esomeprazol/efectos adversos , Mucosa Gástrica/efectos de los fármacos , Inhibidores de la Bomba de Protones/efectos adversos , Adulto , Anciano , Estudios de Casos y Controles , Esomeprazol/uso terapéutico , Femenino , Mucosa Gástrica/metabolismo , Reflujo Gastroesofágico/tratamiento farmacológico , Reflujo Gastroesofágico/metabolismo , Reflujo Gastroesofágico/orina , Humanos , Masculino , Persona de Mediana Edad , Permeabilidad/efectos de los fármacos , Inhibidores de la Bomba de Protones/uso terapéutico , Sacarosa/farmacocinética , Sacarosa/orina , Adulto Joven
9.
Am J Physiol Regul Integr Comp Physiol ; 293(3): R1046-55, 2007 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-17567720

RESUMEN

Restriction of sulfur-containing amino acids (SCAA) has been shown to elicit a similar increase in life span and decrease in age-related morbidity as caloric restriction. The singular importance of epithelial barrier function in both physiological homeostasis and prevention of inflammation raised the issue of examining the effect of SCAA restriction on epithelial tight junction structure and permeability. Using a well-described in vitro, epithelial model, the LLC-PK(1) renal epithelial cell line, we studied the effects of SCAA restriction in culture medium. Reduction of methionine by 90%, cysteine by 50%, and total elimination of cystine resulted in dramatically lower intracellular pools of these amino acids and their metabolite, taurine, but the intracellular pools of the non-SCAA were all elevated. Cell growth and differentiation were maintained, and both confluent cell density and transepithelial short circuit current were unaffected. Certain tight junctional proteins, such as occludin and claudins-1 and -2 were not altered. However, claudins-3 and -7 were significantly decreased in abundance, whereas claudins-4 and -5 were markedly increased in abundance. The functional result of these structural changes was improved barrier function, as evidenced by increased transepithelial electrical resistance and decreased transepithelial (paracellular) diffusion of D-mannitol.


Asunto(s)
Aminoácidos Sulfúricos/fisiología , Proteínas de la Membrana/metabolismo , Uniones Estrechas/efectos de los fármacos , Uniones Estrechas/metabolismo , Envejecimiento/fisiología , Aminoácidos/metabolismo , Animales , Western Blotting , Medios de Cultivo , ADN/biosíntesis , Dieta , Electrofisiología , Células Epiteliales/fisiología , Células Epiteliales/ultraestructura , Técnica del Anticuerpo Fluorescente , Túbulos Renales Proximales/citología , Túbulos Renales Proximales/metabolismo , Células LLC-PK1 , Proteínas de la Membrana/biosíntesis , Proteínas de la Membrana/química , Ocludina , ARN/biosíntesis , Porcinos
10.
Dig Dis Sci ; 51(12): 2326-36, 2006 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-17103306

RESUMEN

Using orally administered sucrose as a probe of gastrointestinal permeability, this study focused on determining whether Barrett's metaplasia exhibits a paracellular transepithelial leak to small nonelectrolytes. Subjects in five separate classes (nonendoscoped, asymptomatic controls; endoscoped, asymptomatic controls; gastroesophageal reflux disease without mucosal complications; grossly visible esophagitis; and Barrett's esophagus) consumed a sucrose solution at bedtime and collected all overnight urine. Urine volume was measured and sucrose concentration was determined by high-performance liquid chromatography. Patients with Barrett's were observed to exhibit a transepithelial leak to sucrose whose mean value was threefold greater than that seen in healthy control subjects or patients with reflux but without any mucosal defect. A parallel study of claudin tight junction proteins in endoscopy biopsy samples showed that whereas Barrett's metaplasia contains dramatically more claudin-2 and claudin-3 than is found in normal esophageal mucosa, it is markedly lower in claudins 1 and 5, indicating very different tight junction barriers.


Asunto(s)
Esófago de Barrett/fisiopatología , Permeabilidad de la Membrana Celular/fisiología , Células Epiteliales/metabolismo , Sacarosa/farmacocinética , Amilasas/sangre , Esófago de Barrett/metabolismo , Esófago de Barrett/patología , Biopsia , Estudios de Casos y Controles , Claudina-1 , Claudina-3 , Claudina-5 , Claudinas , Células Epiteliales/patología , Esófago/citología , Esófago/metabolismo , Esófago/fisiología , Humanos , Proteínas de la Membrana/metabolismo , Metaplasia/metabolismo , Metaplasia/patología , Metaplasia/fisiopatología , Sacarosa/orina , Uniones Estrechas/metabolismo , Uniones Estrechas/patología
11.
Sci STKE ; 2004(216): pe2, 2004 Jan 13.
Artículo en Inglés | MEDLINE | ID: mdl-14734784

RESUMEN

Epithelial cells, and the tight junctions between them, form a polarized barrier between luminal and serosal fluid compartments and segregate luminal growth factors from their basal-lateral receptors. Breakdown of this barrier should allow access of growth factors in the luminal fluid to their receptors on the basal-lateral cell membranes, as recently demonstrated for heregulin and erbB receptors in airway epithelia. It should also allow luminal growth factors to access the stroma. This property may have adaptive value for epithelial tissues in general, as an elegant response to injury, but may also promote cancer formation in premalignant epithelial tissues in which the tight junctions have become chronically leaky to growth factors.


Asunto(s)
Compartimento Celular , Epitelio/patología , Neoplasias/patología , Animales , Compartimento Celular/fisiología , Epitelio/fisiología , Humanos , Uniones Estrechas/patología , Uniones Estrechas/fisiología
12.
J Thromb Haemost ; 1(6): 1245-50, 2003 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-12871326

RESUMEN

A young woman with a history of menorrhagia and easy bruising presented with a functional fibrinogen concentration of 1.8 mg mL(-1), a gravimetric concentration of 3.3 mg mL(-1) and a prolonged thrombin clotting time of 32 s. Both reverse phase analysis and reducing SDS-PAGE revealed a normal profile of Aalpha, Bbeta, and gamma chains. However, non-reducing gels revealed a broadened 340-kDa band, while the 305-kDa band was normal, suggesting a C-terminal truncation of the Aalpha chain. DNA sequencing of all exons and intron boundaries revealed a single heterozygous cytosine deletion at nucleotide 4841 of the Aalpha gene predicting a frameshift and the incorporation of 23 new residues (LMKLPSSTLPQLEKHSQVSSHLC) before termination after residue 517. In agreement with a predicted mass decrease of 9953 Da, the measured mass of the Aalpha(Perth) chain was 56 242 Da, while that of the normal Aalpha(A) chain was 66 189 Da. Tryptic mapping of isolated Aalpha chains revealed a new [M + 2H] ion at 607 m z(-1), corresponding to the predicted penultimate peptide LPSSTLPQLEK. The variant chain was poorly incorporated into plasma fibrinogen at a ratio of Aalpha(Perth)/Aalpha(A) of 0.15 : 1, suggesting the Aalpha(Perth) chain might be out-competed by normal chains during molecular assembly in the hepatocyte. Despite the low expression, polymerization curves showed a decreased V(max) and final turbidity, suggesting the fibrinogen Perth clots are composed of thinner fibers. However, the fibrinolytic rate was very similar to that of the control.


Asunto(s)
Fibrinógenos Anormales/genética , Eliminación de Secuencia , Adulto , Secuencia de Aminoácidos , Coagulación Sanguínea/genética , Análisis Mutacional de ADN , Salud de la Familia , Femenino , Fibrinógenos Anormales/biosíntesis , Fibrinógenos Anormales/metabolismo , Fibrinólisis/genética , Mutación del Sistema de Lectura , Heterocigoto , Humanos , Cinética , Menorragia/genética
13.
Spinal Cord ; 41(1): 44-52, 2003 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-12494320

RESUMEN

OBJECTIVE: To evaluate rehabilitation outcome in a representative sample of older and younger SCI patients. DESIGN: Case series, consecutive sample, survey. SETTING: Tertiary care, spinal cord injury unit (National Spinal Injuries Centre), Stoke Mandeville Hospital. PARTICIPANTS: One hundred and forty-seven male and 45 female newly injured in-patients (consisting of 152 younger adults, age range=16 to 54, and 40 older adults, age range=55 to 85) admitted between 1995 and 1999. INTERVENTION: All patients were actively participating in a comprehensive, multidisciplinary Goal Planning and Needs Assessment rehabilitation programme. MAIN OUTCOME MEASURE: The Needs Assessment Checklist. Specifically designed and developed for the spinal cord injured population, this clinical assessment tool provides a way of assessing and ensuring that rehabilitation programmes are geared toward each patient's individual needs, providing the patient with the skills appropriate to their level of lesion. As part of ongoing psychometric analyses of the Needs Assessment Checklist, internal consistency reliability coefficients are reported for this measure. RESULTS: The type and cause of injury for the older adult group in this study was comparable with previous research. Older adults' rehabilitation gains were comparable to those of the younger age group. Younger adults were more mobile initially after their injury. However, when the two groups were matched for injury characteristics etc. the only differences in final outcome between older and younger adults were in skin management ability. Both groups showed significant improvements in all areas of need in the period between mobilisation and entering the pre-discharge ward. CONCLUSION: These results highlight important considerations for the rehabilitation of older adults and emphasise the need for active, individually tailored rehabilitation programmes. There are specific areas of need (i.e. skin management) where older adults do not achieve comparable levels of independence. Special attention needs to be paid to the problems presented by SCI older adults and efforts should be made to better prepare rehabilitation professionals to adapt to age specific differences.


Asunto(s)
Objetivos , Evaluación de Necesidades , Traumatismos de la Médula Espinal/rehabilitación , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad , Psicometría , Estadísticas no Paramétricas , Resultado del Tratamiento
14.
Dig Dis Sci ; 47(10): 2262-70, 2002 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-12395899

RESUMEN

When transepithelial permeability of rat distal colon is evaluated on the basis of transepithelial electrical resistance, age does not have an effect. Age likewise did not affect the decrease in resistance brought about by phorbol ester exposure. However, age was shown to correlate with increased transepithelial permeability when diffusion of the nonelectrolyte, D-mannitol, was used as an indicator. A phorbol ester-induced increase in transepithelial permeability to D-mannitol was observed to increase with age. Basal permeability to D-mannitol was significantly higher in older rats when the animals were allowed to age on a high-fat diet. Distance from the rectum was shown to be a potential complicating factor in these studies, since distal colon closer to the rectum was observed to have lower transepithelial permeability. The potential effect of such increased leakiness on the increased frequency of colon cancer in older individuals is discussed.


Asunto(s)
Envejecimiento/fisiología , Permeabilidad de la Membrana Celular/fisiología , Colon/fisiología , Conducta Alimentaria/fisiología , Mucosa Intestinal/fisiología , Animales , Permeabilidad de la Membrana Celular/efectos de los fármacos , Colon/efectos de los fármacos , Grasas de la Dieta/administración & dosificación , Difusión , Humanos , Mucosa Intestinal/efectos de los fármacos , Masculino , Manitol/metabolismo , Potenciales de la Membrana/efectos de los fármacos , Potenciales de la Membrana/fisiología , Forbol 12,13-Dibutirato/toxicidad , Ratas , Ratas Endogámicas F344
15.
Phytomedicine ; 9(5): 398-404, 2002 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-12222658

RESUMEN

We have investigated the immunostimulatory activity of the medicinal plant Panax quinquefolius L. (North American ginseng). Rat alveolar macrophages were treated with different extracts from 4-year old roots, and tumour necrosis factor alpha (TNF) production was used as a measure of immunostimulatory activity. Aqueous extracts of P. quinquefolius root (1-100 microg/ml) were found to significantly stimulate alveolar macrophage TNF release. Both a P. quinquefolius methanol extract containing ginsenosides (but no polysaccharides), and pure ginsenoside-Rb1, the major ginsenoside present in P. quinquefolius, were found to be inactive as TNF-stimulating agents. Significant TNF-stimulating activity was found in the extractable polysaccharide fraction, which was hydrolyzed and found to contain glucose, galactose, arabinose, rhamnose, and mannose. This represents the first evidence that North American ginseng exerts cytokine-stimulating activity on macrophages.


Asunto(s)
Adyuvantes Inmunológicos/farmacología , Macrófagos Alveolares/efectos de los fármacos , Panax/química , Polisacáridos/farmacología , Factor de Necrosis Tumoral alfa/biosíntesis , Animales , Cromatografía Líquida de Alta Presión , Macrófagos Alveolares/metabolismo , Masculino , Raíces de Plantas/química , Ratas , Ratas Wistar
16.
Dig Dis Sci ; 46(7): 1490-9, 2001 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-11478501

RESUMEN

The phorbol ester, TPA, transiently increases the transepithelial permeability across the gastrointestinal epithelium formed by IEC-18. There was a significant decrease in transepithelial resistance (R(T)) between 0 and 1.5 hr, accompanied by increased flux of polyethylene glycol (4000 MW), suggesting that the increase was across the tight junction. By 2 hr, the decrease in R(T) reversed and maintained control level. The transepithelial permeability increase was prevented by coincubation with the protein kinase C (PKC) inhibitor bisindolylmaleimide. There was a rapid (within 15 min) translocation of PKC-alpha from the cytosolic to the "membrane-associated" compartment, followed by a down-regulation that was detectable within 60 min of TPA treatment. The down-regulation of PKC-alpha from the membrane was prevented by either calpain inhibitor I or MG-132 and resulted in a sustained permeability increase. The permeability changes were not accompanied by significant effects on the amount or localization of the tight junctional proteins, occludin and ZO-1. However, occludin did show a reversible increase in phosphorylation with TPA treatment. Together these data support a role for PKC-alpha-mediated regulation of barrier permeability in an in vitro model of small intestinal epithelium, perhaps through modulation of the phosphorylation state of the tight junctional protein, occludin.


Asunto(s)
Fenómenos Fisiológicos del Sistema Digestivo , Epitelio/fisiología , Permeabilidad/efectos de los fármacos , Ésteres del Forbol/farmacología , Animales , Línea Celular , Células Cultivadas , Regulación hacia Abajo , Proteínas de la Membrana/metabolismo , Ocludina , Fosforilación , Polietilenglicoles , Proteína Quinasa C/metabolismo , Ratas
17.
Ann N Y Acad Sci ; 936: 331-4, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-11460489

RESUMEN

Previous studies have suggested that clots with thinner fiber diameter lyse at slower rates than clots with thicker fiber diameter. We examined lysis of fibrin clots formed from three variant fibrinogens, each with substitutions in the N-terminal region of the B beta chain. When we measured lysis as the rate of decrease in turbidity at 350 nm, we found that the rate of lysis was slower than normal for clots with thinner fibers. We noted, however, that the time to complete lysis was the same for all clots. Thus, when the data were considered as the percent of lysis with time, we found that the curves were the same as normal. We suggest that a complete and accurate characterization of clot dissolution requires comparison of normalized lysis rates.


Asunto(s)
Fibrina/metabolismo , Fibrinógeno/metabolismo , Fibrinólisis , Cinética , Microscopía Electrónica de Rastreo , Proteínas Recombinantes/metabolismo
19.
Exp Cell Res ; 261(1): 239-49, 2000 Nov 25.
Artículo en Inglés | MEDLINE | ID: mdl-11082294

RESUMEN

The role of PKC-alpha in altered epithelial barrier permeability following the activation of PKC by TPA (12-O-tetradecanoyl phorbol 13-acetate) and bryostatin 1 in LLC-PK1 cells was investigated in this study. Like TPA, bryostatin 1 binds to and activates PKC but unlike TPA, it is not a tumor promoter. TPA at 10(-7) M induced a sustained 95% decrease in transepithelial electrical resistance (R(t)) across LLC-PK1 epithelial cell sheets, while 10(-7) M bryostatin 1 caused only a 30% decrease in R(t), which spontaneously reversed after 5 h. Simultaneous exposure of cell sheets to 10(-7) M TPA and 10(-7) M bryostatin 1 blunted the increase in epithelial permeability observed with 10(-7) M TPA alone. Co-incubation of cell sheets with bryostatin 1 and MG-132, a proteasomal inhibitor, caused a further decrease in R(t) at the 6-h time point and inhibited the recovery in R(t) seen with bryostatin 1 alone at this time point. TPA caused a rapid translocation of PKC-alpha from the cytosol to the membrane of the cell where it remained elevated. Bryostatin 1 treatment resulted in a slower translocation of PKC-alpha from the cytosol to the membrane and a much more rapid downregulation of PKC-alpha, with disappearance from this compartment after only 6 h. The classical PKC inhibitor Go6976 prevented the decrease in R(t) seen with TPA. Treatment of cells with TPA and bryostatin 1 resulted in a PKC-alpha translocation and downregulation profile which more closely resembled that seen with bryostatin 1 alone. Co-incubation of cells with MG-132 and bryostatin 1 caused a slower downregulation of PKC-alpha from the membrane fraction. Bryostatin 1 treatment of cells expressing a dominant/negative form of PKC-alpha resulted in a slower and less extensive decrease in R(t) compared to the corresponding control cells. For both TPA and bryostatin 1, the level of PKC-alpha in the membrane-associated fraction of the treated cells correlated closely with increased transepithelial permeability. Due to its transient effect on tight junction permeability, bryostatin 1 offers a novel pharmacological tool to investigate junctional physiology.


Asunto(s)
Permeabilidad de la Membrana Celular/efectos de los fármacos , Isoenzimas/metabolismo , Lactonas/farmacología , Proteína Quinasa C/metabolismo , Uniones Estrechas/fisiología , Animales , Transporte Biológico , Brioestatinas , Carbazoles/farmacología , Línea Celular , Permeabilidad de la Membrana Celular/fisiología , Cisteína Endopeptidasas/metabolismo , Activación Enzimática , Inhibidores Enzimáticos/farmacología , Células Epiteliales/citología , Células Epiteliales/efectos de los fármacos , Células Epiteliales/fisiología , Indoles/farmacología , Cinética , Leupeptinas/farmacología , Macrólidos , Manitol/farmacocinética , Potenciales de la Membrana/efectos de los fármacos , Complejos Multienzimáticos/metabolismo , Polietilenglicoles/farmacocinética , Complejo de la Endopetidasa Proteasomal , Proteína Quinasa C-alfa , Acetato de Tetradecanoilforbol/farmacología , Uniones Estrechas/efectos de los fármacos
20.
Ann Thorac Surg ; 70(4): 1313-8, 2000 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-11081891

RESUMEN

BACKGROUND: Tumor necrosis factor-alpha (TNF) has been implicated in the development of postoperative morbidity after cardiopulmonary bypass for myocardial revascularization. Despite their postulated roles as modulators of TNF bioavailability, soluble TNF receptors have not been characterized in patients undergoing this procedure and is the focus of this study. METHODS: Soluble tumor necrosis factor receptor I (sTNFRI) and TNF were measured by immunoassay in plasma samples collected from 36 patients at events before, during, and after cardiopulmonary bypass. RESULTS: Plasma concentrations of sTNFRI averaged 1.39 ng/mL at the start of the operation. Preoperative sTNFRI concentrations were found to significantly correlate with a preoperative morbidity assessment score, age, duration of bypass, duration of supplemental oxygen, and length of hospital stay. Plasma sTNFRI increased in all of the patients during the procedure. Plasma concentrations of sTNFRI and TNF did not correlate at any time. CONCLUSIONS: Preoperative measurement of sTNFRI could potentially serve as a reliable indicator for prophylactic treatment with an anti-TNF therapy. Such a therapeutic approach might help attenuate inflammatory processes thought to underlie postoperative morbidity associated with cardiopulmonary bypass.


Asunto(s)
Antígenos CD/sangre , Puente Cardiopulmonar , Puente de Arteria Coronaria , Complicaciones Posoperatorias/sangre , Receptores del Factor de Necrosis Tumoral/sangre , Factor de Necrosis Tumoral alfa/metabolismo , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad , Receptores Tipo I de Factores de Necrosis Tumoral , Valores de Referencia , Factores de Riesgo
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