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1.
Am J Physiol Gastrointest Liver Physiol ; 300(4): G577-85, 2011 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-21193528

RESUMEN

Intraluminal manometry is a tool commonly used to record motility in the human digestive tract. The recorded signal results from a combination of factors, including the hydrodynamic pressure transmitted through the intestinal contents due to contraction of the gut wall and the force of the gut wall acting on the sensors in regions of a luminal occlusion. However, the actual relationships between small bowel wall contraction, the measured intraluminal pressure, and the resultant flow have not been directly addressed. Video recording and high-resolution fiber-optic manometry were used to create spatiotemporal video maps of diameter and intraluminal pressure from isolated segments of rabbit small intestine. In the unstimulated gut, longitudinal muscle contractions were the only detectable motor pattern; circular muscle contractions were elicited by distension or erythromycin (1 µM). Longitudinal muscle contractions were not lumen-occlusive, although they caused measurable low-amplitude changes in pressure. Localized nonpropagating circular muscle contractions caused small localized, nonpropagating peaks of intraluminal pressure. Propagating contractions of circular muscle evoked larger, propagating pressure changes that were associated with outflow. Propagating circular muscle contractions often caused dilation of aboral receiving segments, corresponding to "common cavities"; these were propulsive, despite their low intraluminal pressure. The highest-amplitude pressure events were caused by lumen-occlusive circular muscle contractions that squeezed directly against the catheter. These data allow us to define the complex relationships between wall motion, intraluminal pressure, and flow. A strong correlation between circular and longitudinal muscle contraction and intraluminal pressure was demonstrated. Common-cavity pressure events, caused by propulsion of content by circular muscle contractions into a receptive segment, were often of low amplitude but were highly propulsive. Studies of wall motion in isolated preparations, combined with manometry, can assist in interpretation of pressure recordings in vivo.


Asunto(s)
Motilidad Gastrointestinal/fisiología , Intestino Delgado/fisiología , Contracción Muscular/fisiología , Músculo Liso/fisiología , Animales , Masculino , Manometría , Presión , Conejos , Factores de Tiempo , Grabación en Video
2.
Am J Physiol Gastrointest Liver Physiol ; 298(5): G643-56, 2010 May.
Artículo en Inglés | MEDLINE | ID: mdl-20150245

RESUMEN

The morphology of interstitial cells of Cajal (ICC) in the circular muscle layer of the cynomolgus monkey internal anal sphincter (IAS) and rectum and their relationship to sympathetic and nitrergic nerves were compared by dual-labeling immunohistochemistry. Contractile studies confirmed that nitrergic nerves participate in neural inhibition in both regions whereas sympathetic nerves serve as excitatory motor nerves only in the IAS. Muscle bundles extended from myenteric to submucosal edge in rectum but in the IAS bundles were further divided into "minibundles" each surrounded by connective tissue. Dual labeling of KIT and smooth muscle myosin revealed KIT-positive stellate-shaped ICC (ICC-IAS) within each minibundle. In the rectum intramuscular ICC (ICC-IM) were spindle shaped whereas stellate-shaped ICC were located at the myenteric surface (ICC-MY). ICC were absent from both the myenteric and submucosal surfaces of the IAS. Nitrergic nerves (identified with anti-neuronal nitric oxide synthase antibodies or NADPH diaphorase activity) and sympathetic nerves (identified with anti-tyrosine hydroxylase antibody) each formed a plexus at the myenteric surface of the rectum but not the IAS. Intramuscular neuronal nitric oxide synthase- and tyrosine hydroxylase-positive fibers were present in both regions but were only closely associated with ICC-IM in rectum. Minimal association was also noted between ICC-IAS and cells expressing the nonspecific neuronal marker PGP9.5. In conclusion, the morphology of rectal ICC-IM and ICC-MY is similar to that described elsewhere in the gastrointestinal tract whereas ICC-IAS are unique. The distribution of stellate-shaped ICC-IAS throughout the musculature and their absence from both the myenteric and submucosal surfaces suggest that ICC-IAS may serve as pacemaker cells in this muscle whereas their limited relationship to nerves suggests that they are not involved in neuromuscular transmission. Additionally, the presence of numerous minibundles, each containing both ICC-IAS and nerves, suggests that this muscle functions as a multiunit type muscle.


Asunto(s)
Canal Anal/inervación , Células Intersticiales de Cajal/fisiología , Neuronas Nitrérgicas/citología , Recto/inervación , Sistema Nervioso Simpático/citología , Animales , Femenino , Inmunohistoquímica , Macaca fascicularis , Masculino , Contracción Muscular/fisiología , Óxido Nítrico Sintasa de Tipo I/metabolismo
3.
Br J Pharmacol ; 153(6): 1259-71, 2008 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-18204472

RESUMEN

BACKGROUND AND PURPOSE: During the bladder filling phase, the volume of the urinary bladder increases dramatically, with only minimal increases in intravesical pressure. To accomplish this, the smooth muscle of the bladder wall must remain relaxed during bladder filling. However, the mechanisms responsible for the stabilization of bladder excitability during stretch are unclear. We hypothesized that stretch-dependent K(+) (TREK) channels in bladder smooth muscle cells may inhibit contraction in response to stretch. EXPERIMENTAL APPROACHES: Bladder tissues from mouse, guinea pig and monkey were used for molecular, patch clamp, mechanical, electrical, Ca(2+) imaging and cystometric responses to methionine and its derivatives, which are putative blockers of stretch-dependent K(+) (SDK) channels. KEY RESULTS: SDK channels are functionally expressed in bladder myocytes. The single channel conductance of SDK channels is 89pS in symmetrical K(+) conditions and is blocked by L-methionine. Expressed TREK-1 currents are also inhibited by L-methioninol. All three types of bladder smooth muscle cells from mouse, guinea pig and monkey expressed TREK-1 genes. L-methionine, methioninol and methionine methyl ester but not D-methionine increased contractility in concentration-dependent manner. Methioninol further increased contractility and depolarized the membrane in the presence of blockers of Ca(2+)-activated K(+) conductance. L-methionine induced Ca(2+) waves that spread long distances through the tissue under stretched conditions and were associated with strong contractions. In cystometric assays, methioninol injection increased bladder excitability mimicking overactive bladder activity. CONCLUSIONS AND IMPLICATIONS: Methioninol-sensitive K(+) (SDK, TREK-1) channels appear to be important to prevent spread of excitation through the syncitium during bladder filling.


Asunto(s)
Metionina/farmacología , Músculo Liso/efectos de los fármacos , Bloqueadores de los Canales de Potasio/farmacología , Canales de Potasio de Dominio Poro en Tándem/efectos de los fármacos , Animales , Calcio/metabolismo , Relación Dosis-Respuesta a Droga , Femenino , Expresión Génica , Cobayas , Macaca fascicularis , Masculino , Metionina/administración & dosificación , Metionina/análogos & derivados , Ratones , Contracción Muscular/efectos de los fármacos , Músculo Liso/citología , Técnicas de Placa-Clamp , Canales de Potasio de Dominio Poro en Tándem/metabolismo , Especificidad de la Especie , Vejiga Urinaria/citología , Vejiga Urinaria/efectos de los fármacos , Vejiga Urinaria/metabolismo
4.
Pathologe ; 29 Suppl 2: 181-3, 2008 Nov.
Artículo en Alemán | MEDLINE | ID: mdl-18843491

RESUMEN

A multitude of prognostic and predictive multiparameter algorithms based on the analysis of mRNA have been published in recent years. Many of the algorithms require fresh or fresh frozen tissue as a source of the mRNA. However, practical considerations suggest formalin-fixed paraffin-embedded tissue (FFPE tissue) to be a more suitable starting material for routine diagnostic applications. Therefore, Siemens Healthcare Diagnostics is developing a fully automated method to extract mRNA and DNA from FFPE tissue for use in pathology laboratories. Initially, the method will be used as part of a prognosis assay to predict the likelihood of distant metastasis and death for node-negative breast cancer patients.


Asunto(s)
Algoritmos , Biomarcadores de Tumor/genética , Neoplasias de la Mama/genética , Neoplasias de la Mama/patología , ADN de Neoplasias/genética , Fijadores , Formaldehído , Análisis de Secuencia por Matrices de Oligonucleótidos/instrumentación , Adhesión en Parafina , ARN Mensajero/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/instrumentación , Robótica/instrumentación , Análisis de Matrices Tisulares/instrumentación , Mama/patología , Diseño de Equipo , Femenino , Perfilación de la Expresión Génica , Humanos , Recurrencia Local de Neoplasia/genética , Recurrencia Local de Neoplasia/patología , Pronóstico
5.
Neurogastroenterol Motil ; 30(9): e13349, 2018 09.
Artículo en Inglés | MEDLINE | ID: mdl-29644797

RESUMEN

BACKGROUND: Multiple sclerosis (MS) is an autoimmune disease of the central nervous system that, in addition to motor, sensory, and cognitive symptoms, also causes constipation, which is poorly understood. Here, we characterize gastrointestinal (GI) dysmotility in the experimental autoimmune encephalomyelitis (EAE) mouse model of MS and evaluate whether autoantibodies target the enteric nervous system (ENS) and cause dysmotility. METHODS: EAE was induced in male SJL and B6 mice. GI motility was assessed in vivo and ex vivo in wild type (WT) and B cell-deficient mice. MS and EAE serum was used to survey potential targets in the ENS and changes in the ENS structure were characterized using immunohistochemistry. KEY RESULTS: EAE mice developed accelerated gastric emptying and delayed whole GI transit with reduced colonic motility. Fecal water content was reduced, and colonic migrating myoelectrical complexes (CMMC) and slow waves were less frequent. Colons from EAE mice exhibited decreased GFAP levels in glia. Sera from MS patients and from EAE mice targeted ENS neurons and glia. B-cell deficiency in EAE protected against colonic dysmotility. CONCLUSIONS & INFERENCES: Consistent with symptoms experienced in MS, we demonstrate that EAE mice widely exhibit features of GI dysmotility that persisted in the absence of extrinsic innervation, suggesting direct involvement of ENS neurocircuitry. The absence of GI dysmotility in B cell-deficient mice with EAE together with EAE and MS serum immunoreactivity against ENS targets suggests that MS could be classified among other diseases known to induce autoimmune GI dysmotility.


Asunto(s)
Autoanticuerpos/inmunología , Estreñimiento/inmunología , Encefalomielitis Autoinmune Experimental/complicaciones , Encefalomielitis Autoinmune Experimental/inmunología , Motilidad Gastrointestinal/inmunología , Animales , Sistema Nervioso Entérico/inmunología , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Esclerosis Múltiple/complicaciones , Esclerosis Múltiple/inmunología , Neuroglía/inmunología , Neuronas/inmunología
6.
Neurogastroenterol Motil ; 19(11): 869-78, 2007 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-17988274

RESUMEN

Until recently, it was generally assumed that the only intrinsic sensory neuron, or primary afferent neuron, in the gut was the after-hyperpolarizing AH/Type II neuron. AH neurons excited by local chemical and mechanical stimulation of the mucosa appear to be necessary for activating the peristaltic reflex (oral excitation and anal inhibition of the muscle layers) and anally propagating ring like contractions (peristaltic waves) that depend upon smooth muscle tone. However, our recent findings in the guinea-pig distal colon suggest that different neurochemical classes of interneuron in the colon are also mechanosensitive in that they respond directly to changes in muscle length, rather than muscle tone or tension. These interneurons have electrophysiological properties consistent with myenteric S-neurons. Ascending and descending interneurons respond directly to circumferential stretch by generating an ongoing polarized peristaltic reflex activity (oral excitatory and anal inhibitory junction potentials) in the muscle for as long as the stimulus is maintained. Some descending (nitric oxide synthase +ve) interneurons, on the other hand, appear to respond directly to longitudinal stretch and are involved in accommodation and slow transit of faecal pellets down the colon. This review will present recent evidence that suggests some myenteric S interneurons, in addition to AH neurons, behave as intrinsic sensory neurons.


Asunto(s)
Sistema Nervioso Entérico/fisiología , Interneuronas/fisiología , Mucosa Intestinal/inervación , Animales , Colon/inervación , Colon/fisiología , Electrofisiología , Motilidad Gastrointestinal/fisiología , Cobayas , Mucosa Intestinal/fisiología , Neuronas Aferentes/fisiología , Peristaltismo/fisiología
7.
Oncogene ; 8(10): 2781-90, 1993 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-8378087

RESUMEN

We have generated a series of conditionally active Fos and FosB proteins by fusion with a C-terminal fragment of the human estrogen receptor (ER) which harbours the ligand binding site and the overlapping hormone-inducible transactivation domain TAF-2. The chimaeric Fos-ER proteins showed estrogen-inducible activation of TRE (TPA-responsive element)-directed transcription and hormone-dependent transformation of fibroblasts. These properties of the fusion proteins were independent of the transregulatory and transforming properties of their normal non-fused counterparts c-Fos, v-Fos, FosB-L and FosB-S. Thus c-Fos-ER and FosB-S-ER were strong transforming proteins in the presence of hormone, although c-Fos and FosB-S possess only marginal oncogenic properties. In addition, all fusion proteins showed increased transactivation in the presence of estrogen, again most noticeable in the case of c-Fos-ER and FosB-S-ER. The ER-fusion thus basically eliminated the differences in the transactivating potential seen among the various native Fos proteins. Our data therefore provide evidence: (i) that the hormone binding domain of the human estrogen receptor, apart from delivering hormonal control to a heterologous protein, can have profound effects on the activity of certain transcription factors, particularly on proteins with weak oncogenic and/or transregulatory potential, and (ii) that the transforming potential of c-Fos and FosB-S can be dramatically elevated by increasing their transactivating properties.


Asunto(s)
Transformación Celular Neoplásica/genética , Elementos de Facilitación Genéticos , Receptores de Estrógenos , Proteínas Recombinantes de Fusión/farmacología , Transcripción Genética/efectos de los fármacos , Activación Transcripcional/efectos de los fármacos , Células 3T3 , Animales , Transformación Celular Neoplásica/patología , Células Cultivadas , Ratones , Proteínas Proto-Oncogénicas c-fos , Ratas , Receptores de Estrógenos/genética , Proteínas Recombinantes de Fusión/genética , Transfección
8.
Oncogene ; 11(3): 475-84, 1995 Aug 03.
Artículo en Inglés | MEDLINE | ID: mdl-7630631

RESUMEN

E-cadherin has been identified as a tumor (invasion) suppressor gene, which is mutated in 50% of diffuse-type human gastric carcinomas. In other carcinomas, the expression of E-cadherin is down-regulated in the poorly differentiated cells such as from breast, bladder, lung and colon. We have here examined the in vivo properties of the genomic E-cadherin promoter in well and poorly differentiated carcinoma cell lines in order to gain insights into the mechanisms of E-cadherin down-regulation in tumors. In vivo footprinting analysis revealed that positive regulatory elements of the E-cadherin promoter (a GC-rich region, the CCAAT-box and a palindromic element) are specifically bound by transcription factors in E-cadherin-expressing but not in non-expressing cells. The tested cell systems include more than a dozen carcinomas cell lines as well as mammary epithelial cells where E-cadherin expression can be switched off by activation of a Fos-estrogen receptor fusion protein and rhabdomyosarcoma cells where E-cadherin expression was induced by transfection with E1A. Mapping of DNase I hypersensitive sites showed that the chromatin structure in the promoter region is loosened in expressing but condensed in non-expressing cells. Furthermore, the endogenous E-cadherin promoter is specifically methylated at CpG sites in the undifferentiated cells. We also show that the in vivo properties of the promoter in E-caherin-negative carcinoma cells are similar as in mesenchymal cells, i.e. fibroblasts or sarcoma cells. These data suggest that silencing of the E-cadherin promoter during epithelialmesenchymal transition and tumor progression is due to a loss of factor binding in vivo and to chromatin rearrangement in the regulatory region.


Asunto(s)
Cadherinas/genética , Carcinoma/genética , Carcinoma/patología , Cromatina/ultraestructura , Regiones Promotoras Genéticas , Animales , Secuencia de Bases , Sitios de Unión , Proteínas de Unión al ADN/metabolismo , Desoxirribonucleasa I/farmacología , Regulación Neoplásica de la Expresión Génica , Genes , Técnicas In Vitro , Metilación , Ratones , Datos de Secuencia Molecular , Oligodesoxirribonucleótidos/química , ARN Mensajero/genética , Células Tumorales Cultivadas
10.
Minerva Anestesiol ; 81(10): 1070-8, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-25658171

RESUMEN

BACKGROUND: A controversy exists regarding which monitoring technique is superior in cases in which general anesthesia (GA) is necessary for carotid endarterectomy (CEA). Multimodal evoked potential (mEP) monitoring was investigated under GA during CEA and compared with a historical control group undergoing neurological evaluations awake under loco-regional anesthesia (LA). METHODS: We retrospectively studied 651 patients undergoing elective CEA. In groupHISTORY (N.=349; 1997-1999) LA was provided using superficial or deep/superficial cervical plexus blocks. In groupmEP, (N.=302; 2009-2013) GA was performed by administering remifentanil/propofol infusion. The multimodal EPs included the median-nerve-somatosensory and motor evoked potentials. The primary outcome was the rate of technical failure. The arterio-arterial shunt rate and immediate postoperative motor outcomes were also compared. RESULTS: GroupmEP showed a significantly lower rate of technical failure (OR 0.17; CI 0.03-0.6; P=0.002). Because the groups differed systematically, logistic regression analysis was used to compare shunt rates and motor outcomes. Since shunt rates were 8.3% (groupmEP) versus 8.2% (groupHISTORY), but logistic regression model showed significant differences (OR 3.77; CI 1.67-8.95; P=0.001) correct comparison was impossible. Immediate postoperative deficits were 4.3% (groupmEP) and 4.9% (groupHISTORY); logistic regression analysis: transient OR 0.77, CI 0.28 to 0.22, P=0.61 and permanent OR 0.37, CI 0.02-7.74, P=0.49. CONCLUSION: Monitoring mEPs was associated with less technical failure than awake evaluation and showed similar motor outcomes. Because the groups differed systematically, the interpretation of shunt rates was impossible. Monitoring mEP should be considered to detect intraoperative ischemia in cases in which patients undergo CEA under GA.


Asunto(s)
Endarterectomía Carotidea/métodos , Potenciales Evocados , Monitorización Neurofisiológica Intraoperatoria/métodos , Examen Neurológico , Anciano , Falla de Equipo/estadística & datos numéricos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Sueño , Resultado del Tratamiento , Vigilia
11.
J Comp Neurol ; 397(2): 268-80, 1998 Jul 27.
Artículo en Inglés | MEDLINE | ID: mdl-9658288

RESUMEN

The projections of enteric neurons to the circular muscle of the guinea pig gastric corpus were investigated systematically by using the retrogradely transported fluorescent carbocyanine dye 1,1'-didodecyl-3,3,3',3'-tetramethyl indocarbocyanine perchlorate (DiI), applied to the muscle layer or myenteric plexus in vitro. DiI-labeled motor neuron cell bodies were located up to 6.3 mm aboral, 17 mm oral, and up to 20 mm circumferential to the DiI application site. Labeled nerve fibers ran for long distances from the DiI application site toward the greater and lesser curvatures, where they coursed parallel to the bundles of the "gastric sling" muscle. The majority of labeled cells were located toward the lesser curvature of the stomach. Nerve cell bodies that were aboral to the DiI application site were usually small, immunoreactive for choline acetyltransferase, and, thus, were likely to be excitatory motor neurons. Neurons that were located orally were larger, fewer in number, and immunoreactive for nitric oxide synthase and, thus, were likely to be inhibitory motor neurons. Application of DiI directly to the myenteric plexus filled neurons up to 15 mm aborally and up to 21 mm orally but labeled few neurons circumferentially. All nerve cells that were filled from either the circular muscle or the myenteric plexus had Dogiel type I morphological features. These results demonstrate a clear polarity of projection of inhibitory and excitatory motor neurons and a functionally continuous innervation of the circular and gastric sling muscle layers. Nonmotor neurons in the myenteric plexus were demonstrated, but neurons with Dogiel type II morphological features are apparently absent.


Asunto(s)
Cobayas/anatomía & histología , Neuronas Motoras/fisiología , Músculo Liso/inervación , Plexo Mientérico/citología , Estómago/inervación , Animales , Carbocianinas , Femenino , Colorantes Fluorescentes , Procesamiento de Imagen Asistido por Computador , Inmunohistoquímica , Masculino , Técnicas de Cultivo de Órganos
12.
Toxicol Sci ; 57(2): 338-44, 2000 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-11006363

RESUMEN

The purpose of this study was to investigate whether activation of the nuclear receptor PPARalpha is needed for protection from acetaminophen (APAP) hepatotoxicity produced by repeated administration of the peroxisome proliferator clofibrate (CFB). Female wild-type and PPARalpha-null mice received corn oil vehicle or 500 mg CFB/kg, ip, daily for 10 days. They were then fasted overnight (18 h) and either killed at 4 or 24 h after challenge with 400 mg APAP/kg. Controls received 50% propylene glycol vehicle only. In this model of CFB hepatoprotection, liver injury was assessed by measuring plasma sorbitol dehydrogenase activity and by histopathology at 24 h after APAP challenge. Significant hepatocellular necrosis was evident in both corn oil-pretreated PPARalpha-null and wild-type mice at 24 h after APAP challenge. In agreement with previous studies, CFB-pretreated wild-type mice showed marked protection against APAP toxicity. In contrast, CFB did not provide protection against APAP hepatotoxicity in the PPARalpha-null mice. Similarly, at 4 h after APAP challenge, hepatic glutathione depletion and selective arylation of cytosolic proteins were reduced significantly in CFB-pretreated wild-type mice, but not in PPARalpha-null mice. The lack of changes in APAP binding and NPSH depletion in CFB-pretreated, PPARalpha-null mice is consistent with the presence of significant liver injury at 24 h in this treatment group. These findings demonstrate that the protection against APAP hepatotoxicity by peroxisome proliferator treatment is mediated by the activation of PPARalpha.


Asunto(s)
Acetaminofén/toxicidad , Analgésicos/toxicidad , Enfermedad Hepática Inducida por Sustancias y Drogas/prevención & control , Clofibrato/farmacología , Hipolipemiantes/farmacología , Hígado/efectos de los fármacos , Receptores Citoplasmáticos y Nucleares/metabolismo , Factores de Transcripción/metabolismo , Acetaminofén/administración & dosificación , Administración Oral , Analgésicos/administración & dosificación , Animales , Enfermedad Hepática Inducida por Sustancias y Drogas/sangre , Enfermedad Hepática Inducida por Sustancias y Drogas/patología , Clofibrato/administración & dosificación , Femenino , Glutatión/metabolismo , Homocigoto , Hipolipemiantes/administración & dosificación , Técnicas para Inmunoenzimas , Inyecciones Intraperitoneales , L-Iditol 2-Deshidrogenasa/sangre , Hígado/metabolismo , Hígado/patología , Ratones , Ratones Noqueados , Necrosis , Tamaño de los Órganos/efectos de los fármacos , Receptores Citoplasmáticos y Nucleares/genética , Factores de Transcripción/genética
13.
Neurogastroenterol Motil ; 14(6): 677-88, 2002 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-12464090

RESUMEN

Our aim was to evaluate topographically specific gastric motility changes induced by graded vagal activation. A recently developed method of constructing spatio-temporal maps of motility from video movies was adapted to the in vitro perfused guinea-pig stomach with an intact vagal nerve supply. In the unstimulated preparation, spontaneous activity was low or absent. Bilateral vagal stimulation with frequencies as low as 0.2 Hz triggered weak anally, and in some cases orally, propagating antral contractions at rates of about 5-6 min-1. Upon stimulation with higher frequencies, antral contractions increased significantly in length (starting more proximally) and amplitude, and produced large pressure peaks of up to 25 hPa, with maximal effects at 2-4 Hz. In contrast, the speed of propagation and the interval between peristaltic waves did not change with vagal stimulation at any frequency. Vagal stimulation also produced a significant and frequency-dependent enlargement of the fundus with a maximal effect at 4 Hz. It is concluded that a very low tonic vagal activity is apparently necessary and sufficient to express basic antral motility, while more sustained vagal activity is necessary for high-amplitude gastric contractions and significant sustained fundic relaxation. The constant interval between propagating contractions supports the concept that vagal input impinges on intrinsic enteric neural circuits that have a modulatory role in the myogenic mechanism underlying slow-wave peristalsis, rather than directly on gastric musculature.


Asunto(s)
Motilidad Gastrointestinal/fisiología , Contracción Muscular/fisiología , Estómago/inervación , Grabación en Video , Animales , Estimulación Eléctrica , Femenino , Cobayas , Procesamiento de Imagen Asistido por Computador , Masculino , Músculo Liso/fisiología , Técnicas de Cultivo de Órganos , Nervio Vago/fisiología , Grabación en Video/métodos
14.
Neurogastroenterol Motil ; 13(5): 483-92, 2001 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-11696110

RESUMEN

We investigated and quantified the spontaneous patterns of motility in the isolated guinea-pig proximal and distal colon taken from adult animals. During spontaneous emptying, profiles of proximal and distal colon were recorded with a video camera, and image analysis was used to construct spatio-temporal maps of the motions of the intestinal wall. Four patterns of motility were recorded. In the proximal colon there were neurally mediated contractions that propagated in the aboral direction at 4.1 mm s(-1), gently pushing the soft contents aborally; these are likely to represent spontaneous peristaltic behaviour. A second pattern, insensitive to tetrodotoxin (TTX; 0.6 microM), consisted, in both oral and aboral propagation, of shallow contractions of the circular muscle (ripples). These contractions propagated aborally at 2.8 +/- 0.45 mm s(-1) and orally at 2.03 +/- 0.31 mm s(-1) (n=10). Of these TTX-resistant contractions, 22.5% propagated both orally and aborally from a common origin. The orally propagated component of these myogenic contractions is likely to correspond to the antiperistalsis widely described in the proximal colon. In the distal colon, two patterns of motor activity were observed. One, induced by natural or artificial pellets, consisted of peristaltic contractions that pushed the pellets aborally at 0.8 mm s(-1) and expelled a pellet every 108 s. In the interval between pellet propulsion and after the distal colon had emptied all of its pellets a second, nerve-mediated pattern of motor activity, consisting of clusters of annular circular muscle contractions separated by short dilated regions, slowly propagated aborally at 0.3 mm s(-1). Both of these motor patterns were abolished by TTX (0.6 microM). A latex balloon, inserted at the oral end of the empty isolated distal colon and inflated to a size similar to faecal pellets, was propelled at 1.4 mm s(-1). Epoxy resin-covered natural pellets were propelled at a similar speed of 1.6 mm s(-1). Our data revealed that myogenic and neurogenic patterns of propagated contractions in the colon occur in isolated preparations and are involved in emptying the colon.


Asunto(s)
Motilidad Gastrointestinal/fisiología , Intestino Grueso/fisiología , Complejo Mioeléctrico Migratorio/fisiología , Peristaltismo/fisiología , Animales , Cobayas , Músculo Liso/fisiología , Grabación de Cinta de Video
15.
Toxicology ; 127(1-3): 1-10, 1998 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-9699788

RESUMEN

Pretreatment of mice with clofibrate (CFB) has been shown to protect against acetaminophen (APAP) hepatotoxicity. To determine if pretreatment with CFB prevents the toxicity of other model hepatotoxicants, male C57BL6J or CD-1 mice received 500 mg CFB/kg, i.p., daily for 10 days, and then were challenged with either 250 mg bromobenzene (BrB)/kg, 0.025 ml carbon tetrachloride (CCl4)/kg or 0.5 ml chloroform (CHCl3)/kg. Liver and kidney injury was assessed by plasma sorbitol dehydrogenase activity (SDH) and blood urea nitrogen (BUN), respectively and histopathology. Challenge with BrB significantly elevated plasma SDH activity in C57Bl6J mice. This was prevented in CFB pretreated mice receiving the same dose of BrB. Changes in BUN were not detected in either group of BrB treated mice. Similarly, pretreatment of male CD-1 mice with CFB significantly reduced CCl4-induced elevation in plasma SDH activity, with no BUN elevation detected in either group. CFB pretreatment also diminished elevation in plasma SDH activity produced by CHCl3 in CD-1 mice, while BUN was significantly elevated in both groups, indicating that CFB did not protect against CHCl3-induced nephrotoxicity. Histopathological examination of liver and kidney sections confirmed these results. This study shows that mice pretreated with CFB were protected from toxicity at 24 h after challenge with other model hepatotoxic agents besides APAP.


Asunto(s)
Anticolesterolemiantes/farmacología , Enfermedad Hepática Inducida por Sustancias y Drogas/tratamiento farmacológico , Clofibrato/farmacología , Hígado/efectos de los fármacos , Administración Oral , Animales , Anticolesterolemiantes/administración & dosificación , Nitrógeno de la Urea Sanguínea , Bromobencenos/toxicidad , Tetracloruro de Carbono/toxicidad , Enfermedad Hepática Inducida por Sustancias y Drogas/patología , Cloroformo/toxicidad , Clofibrato/administración & dosificación , Inyecciones Intraperitoneales , Riñón/efectos de los fármacos , Riñón/patología , L-Iditol 2-Deshidrogenasa/sangre , Hígado/ultraestructura , Masculino , Ratones , Ratones Endogámicos C57BL , Microcuerpos/efectos de los fármacos , Microcuerpos/patología , Compuestos de Sulfhidrilo/análisis
16.
Food Chem Toxicol ; 39(3): 271-8, 2001 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-11278059

RESUMEN

The non-metabolizable organic anion indocyanine green (ICG) has been shown previously to reduce markedly the biliary secretion of acetaminophen, particularly the glutathione conjugate of APAP (APAP-GSH), suggesting that this APAP metabolite may compete with other xenobiotics for excretion into the bile via a canalicular organic anion transport process. This study was conducted to determine whether changes in the biliary disposition of APAP induced by ICG could lead to alterations in susceptibility to APAP hepatotoxicity. To investigate this, groups of overnight-fasted male CD-1 mice received 30 micromol ICG/kg, intravenously, immediately prior to APAP dosing (500 mg/kg, ip). Controls were given propylene glycol vehicle. Mice were killed at 4 h after APAP challenge for immunochemical analysis of cytosolic protein arylation and determination of non-protein sulfhydryl (NPSH) depletion, or at 12 and 24 h for biochemical and histological assessment of liver injury. Elevated plasma sorbitol dehydrogenase activity and centrilobular hepatocellular necrosis was present in control mice receiving APAP at 12 and 24 h. Treatment with ICG did not alter susceptibility to APAP toxicity when measured at 12 h after challenge. However, the severity of histologic lesions in the ICG-APAP group was significantly lower at 24 h after challenge. Furthermore, treatment with ICG did not alter APAP-induced glutathione depletion or cytosolic protein arylation. These data suggest that the organic anion ICG has a protective effect on APAP toxicity that promotes a faster recovery from liver injury.


Asunto(s)
Acetaminofén/toxicidad , Analgésicos no Narcóticos/toxicidad , Enfermedad Hepática Inducida por Sustancias y Drogas/patología , Enfermedad Hepática Inducida por Sustancias y Drogas/prevención & control , Colorantes/uso terapéutico , Verde de Indocianina/uso terapéutico , Animales , Bilis/metabolismo , Citosol/efectos de los fármacos , Citosol/metabolismo , Inmunohistoquímica , L-Iditol 2-Deshidrogenasa/metabolismo , Masculino , Ratones , Ratones Endogámicos ICR , Compuestos de Sulfhidrilo/metabolismo , Factores de Tiempo
17.
J Toxicol Environ Health A ; 58(3): 171-86, 1999 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-10522648

RESUMEN

Acetaminophen (APAP)-induced hepatocellular necrosis can be prevented by treatment with peroxisome proliferators. This protection is associated with lowered protein arylation and glutathione depletion in mice. Peroxisome proliferators have been shown to activate nuclear receptors. These receptors, termed peroxisome proliferator activated receptors (PPARs), can also be activated by free fatty acids. This study was designed to determine if treatment with the PPAR activator docosahexaenoic acid (DHA) would also lower APAP toxicity. Male CD-1 mice received 250 mg DHA/kg or 500 mg clofibrate (CFB)/kg, i.p., for 5 d. Controls received corn oil vehicle, i.p. After overnight fasting, mice received 800 mg APAP/kg, p.o. At 24 h after APAP, hepatotoxicity was evident in control mice by elevated plasma sorbitol dehydrogenase activity (SDH) and histologic evidence of hepatic degeneration and necrosis. As expected, CFB pretreatment significantly decreased this. Similarly, DHA protected against APAP-induced hepatotoxicity at 24 h after challenge. However, treatment with DHA did not increase hepatic glutathione prior to APAP, as previously shown with CFB. Interestingly, DHA did not increase palmitoyl coenzyme A (CoA) oxidase activity or other biochemical parameters associated with peroxisome proliferation after 5 d of treatment at 250 mg/kg. No significant alterations in microsomal APAP glucuronidation or cytochrome P-450-mediated bioactivation were detected either. Collectively, these results show that DHA also prevents APAP-induced hepatotoxicity at 24 h after challenge. However, the association between resistance against APAP-induced liver injury, PPAR activation, and peroxisome proliferation is not clearly understood.


Asunto(s)
Acetaminofén/antagonistas & inhibidores , Acetaminofén/toxicidad , Analgésicos no Narcóticos/antagonistas & inhibidores , Analgésicos no Narcóticos/toxicidad , Enfermedad Hepática Inducida por Sustancias y Drogas/prevención & control , Ácidos Docosahexaenoicos/farmacología , Receptores Citoplasmáticos y Nucleares/efectos de los fármacos , Factores de Transcripción/efectos de los fármacos , Animales , Anticolesterolemiantes/farmacología , Biotransformación/efectos de los fármacos , Western Blotting , Enfermedad Hepática Inducida por Sustancias y Drogas/metabolismo , Enfermedad Hepática Inducida por Sustancias y Drogas/patología , Clofibrato/farmacología , Citocromo P-450 CYP4A , Sistema Enzimático del Citocromo P-450/metabolismo , Glucuronatos/metabolismo , Hígado/enzimología , Hígado/patología , Pruebas de Función Hepática , Masculino , Ratones , Ratones Endogámicos , Microsomas Hepáticos/efectos de los fármacos , Microsomas Hepáticos/enzimología , Microsomas Hepáticos/metabolismo , Oxigenasas de Función Mixta/metabolismo , Tamaño de los Órganos/efectos de los fármacos , Palmitoil Coenzima A/metabolismo , Receptores Citoplasmáticos y Nucleares/metabolismo , Succinato Deshidrogenasa/metabolismo , Compuestos de Sulfhidrilo/metabolismo , Factores de Transcripción/metabolismo
18.
Avian Dis ; 46(2): 509-14, 2002.
Artículo en Inglés | MEDLINE | ID: mdl-12061668

RESUMEN

A flock of 810 pheasants experienced 6.2% mortality over 6 days. Affected birds were weak and lethargic for up to 24 hr before death. Examined birds were thin, and gross lesions consisted of thick opaque crops and cecal cores. Histologically, there was capillariasis of the crop and multifocal ulcerative typhlitis with Heterakis spp. infection, and numerous systemic intravascular monocytes were filled with clusters of blue rod-shaped organisms. The organisms were gram-positive bacilli by Brown and Brenn staining and ultrastructural analysis. Liver bacterial cultures were negative for pathogenic bacteria. Erysipelas septicemia was diagnosed by an Erysipelothrix species-specific polymerase chain reaction method with the substrate DNA isolated from formalin-fixed, paraffin-embedded liver.


Asunto(s)
Enfermedades de las Aves/diagnóstico , Infecciones por Erysipelothrix/diagnóstico , Reacción en Cadena de la Polimerasa/veterinaria , Sepsis/veterinaria , Animales , Enfermedades de las Aves/microbiología , Enfermedades de las Aves/patología , Aves , Buche de las Aves/patología , ADN Bacteriano/aislamiento & purificación , Erysipelothrix/genética , Erysipelothrix/aislamiento & purificación , Erysipelothrix/ultraestructura , Infecciones por Erysipelothrix/microbiología , Infecciones por Erysipelothrix/patología , Femenino , Inmunohistoquímica/veterinaria , Masculino , Microscopía Electrónica/veterinaria , Reacción en Cadena de la Polimerasa/métodos , Sepsis/diagnóstico , Sepsis/microbiología , Sepsis/patología
19.
J Am Vet Med Assoc ; 199(7): 907-8, 1991 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-1769880

RESUMEN

Branchial cleft cyst was diagnosed in a 6-month-old Angus bull with a large swelling in the distal ventral neck region. A definitive diagnosis could not be attained from results of the clinical examination, radiography, and ultrasonography. Diagnosis was made from histologic examination of the surgically removed mass. Branchial cleft cysts are remnants of the branchial apparatus and are considered rare in domestic animals. The differential diagnosis should include the thymic form of bovine viral leukosis, thymoma, abscess, goiter, and thyroid gland tumors as well as other rare cysts that can develop in the same location.


Asunto(s)
Región Branquial , Enfermedades de los Bovinos/cirugía , Quistes/veterinaria , Animales , Región Branquial/patología , Región Branquial/cirugía , Bovinos , Enfermedades de los Bovinos/patología , Quistes/patología , Quistes/cirugía , Masculino
20.
Urologe A ; 17(3): 194-200, 1978 May.
Artículo en Alemán | MEDLINE | ID: mdl-653912

RESUMEN

On the basis of satisfactory results with a new magnetic stoma seal in colostomy patients, this seal, consisting of a magnetic ring and cap, was used in an experimental study to convert the colonic conduit into a continent reservoir. The aim of the study, involving 16 dogs, was to find a method of ring implantation that would avoid infection of the ring and yield complete continence in a higher percentage than had been achieved so far in patients. Complete continence was obtained in all animals but there was a 75% incidence of immediate and delayed infection of the magnetic ring when the ring was inserted transcutaneously. In contrast, all rings were well accepted by the tissue when the procedure was staged with the ring being implanted transperitoneally several weeks prior to fashioning of the conduit. The general problems arising from the colonic conduit when used as continent reservoir are known from the results of colocystoplasty, coloprostatoplasty and colourethroplasty, which are reviewed and compared with our observations. Residual urine was low due to an ideal energy-balance pattern. Coloureteric reflux was successfully prevented in all cases operated on by a long-tunnel modification of the Leadbetter-Clarke technique. Hyperchloremic acidosis and renal function deterioration were not observed. All conduits were infected.


Asunto(s)
Derivación Urinaria/métodos , Animales , Colon/cirugía , Perros , Femenino , Magnetismo , Complicaciones Posoperatorias/prevención & control , Vejiga Urinaria/cirugía , Derivación Urinaria/instrumentación , Incontinencia Urinaria/prevención & control
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