RESUMO
BACKGROUND: We proposed that a test for sensitivity to the adjuvant endocrine therapy component of treatment for patients with stage II-III breast cancer (SET2,3) should measure transcription related to estrogen and progesterone receptors (SETER/PR index) adjusted for a baseline prognostic index (BPI) combining clinical tumor and nodal stage with molecular subtype by RNA4 (ESR1, PGR, ERBB2, and AURKA). PATIENTS AND METHODS: Patients with clinically high-risk, hormone receptor-positive (HR+), human epidermal growth factor receptor 2 (HER2)-negative (HR+/HER2-) breast cancer received neoadjuvant taxane-anthracycline chemotherapy, surgery with measurement of residual cancer burden (RCB), and then adjuvant endocrine therapy. SET2,3 was measured from pre-treatment tumor biopsies, evaluated first in an MD Anderson Cancer Center (MDACC) cohort (n = 307, 11 years' follow-up, U133A microarrays), cut point was determined, and then independent, blinded evaluation was carried out in the I-SPY2 trial (n = 268, high-risk MammaPrint result, 3.8 years' follow-up, Agilent-44K microarrays, NCI Clinical Trials ID: NCT01042379). Primary outcome measure was distant relapse-free survival. Multivariate Cox regression models tested prognostic independence of SET2,3 relative to RCB and other molecular prognostic signatures, and whether other prognostic signatures could substitute for SETER/PR or RNA4 components of SET2,3. RESULTS: SET2,3 added independent prognostic information to RCB in the MDACC cohort: SET2,3 [hazard ratio (HR) 0.23, P = 0.004] and RCB (HR 1.77, P < 0.001); and the I-SPY2 trial: SET2,3 (HR 0.27, P = 0.031) and RCB (HR 1.68, P = 0.008). SET2,3 provided similar prognostic information irrespective of whether RCB-II or RCB-III after chemotherapy, and in both luminal subtypes. Conversely, RCB was most strongly prognostic in cancers with low SET2,3 status (MDACC P < 0.001, I-SPY2 P < 0.001). Other molecular signatures were not independently prognostic; they could effectively substitute for RNA4 subtype within the BPI component of SET2,3, but they could not effectively substitute for SETER/PR index. CONCLUSIONS: SET2,3 added independent prognostic information to chemotherapy response (RCB) and baseline prognostic score or subtype. Approximately 40% of patients with clinically high-risk HR+/HER2- disease had high SET2,3 and could be considered for clinical trials of neoadjuvant endocrine-based treatment.
Assuntos
Neoplasias da Mama , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Biomarcadores Tumorais/genética , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/genética , Feminino , Hormônios/uso terapêutico , Humanos , Terapia Neoadjuvante , Recidiva Local de Neoplasia , Prognóstico , Receptor ErbB-2/genética , Receptores de Progesterona/genéticaRESUMO
Convective transport is an important phenomenon for nanomedicine delivery. We present an imaging-based approach to recover tissue properties that are significant in the accumulation of nanoparticles delivered via systemic methods. The classical pharmacokinetic analysis develops governing equations for the particle transport from a first principle mass balance. Fundamentally, the governing equations for compartmental mass balance represent a spatially invariant mass transport between compartments and do not capture spatially variant convection phenomena. Further, the parameters recovered from this approach do not necessarily have direct meaning with respect to the governing equations for convective transport. In our approach, a framework is presented for directly measuring permeability in the sense of Darcy flow through porous tissue. Measurements from our approach are compared to an extended Tofts model as a control. We demonstrate that a pixel-wise iterative clustering algorithm may be applied to reduce the parameter space of the measurements. We show that measurements obtained from our approach are correlated with measurements obtained from the extended Tofts model control. These correlations demonstrate that the proposed approach contains similar information to an established compartmental model and may be useful in providing an alternative theoretical framework for parameterizing mathematical models for treatment planning and diagnostic studies involving nanomedicine where convection dominated effects are important.
Assuntos
Convecção , Nanopartículas , Algoritmos , Modelos Teóricos , PorosidadeRESUMO
The lumbar artery perforator (LAP) flap is a relatively new procedure that can be utilized to manage lumbosacral defects in addition to reconstructing distal body parts as well, such as breast reconstruction. This fasciocutaneous flap is designed based on the LAPs small arteries that emerge from the lumbar arteries then move superficially piercing overlying tissues to perforate the lumbar fascia and supply the skin and subcutaneous tissue; However, anatomical and clinical studies regarding the LAP flap and its perforators are sparse in the literature, and the results are even contradicting. This article will discuss the LAP flap, the anatomy of its perforators, and the clinical aspects about its usage. In addition, we explore its preoperative imaging evaluation, and deliver a guide on image reporting and radiological data that will benefit the surgeon most during the procedure.
Assuntos
Região Lombossacral/irrigação sanguínea , Retalho Perfurante/irrigação sanguínea , Artérias/anatomia & histologia , Artérias/diagnóstico por imagem , Angiografia por Tomografia Computadorizada , Humanos , Imageamento Tridimensional , Região Lombossacral/diagnóstico por imagem , Cuidados Pré-OperatóriosRESUMO
INTRODUCTION: Transthoracic echocardiography (TTE) is the primary tool for the assessment of cardiac structure and function in dogs but is challenging in English bulldogs due to dorsoventral compression of the thorax, obesity, and narrow intercostal spaces. Multi-detector computed tomography angiography (CTA) may overcome the conformational obstacles of cardiac imaging in this breed. ANIMALS: Eleven client-owned English bulldogs. MATERIALS AND METHODS: Prospective clinical trial with paired analysis of TTE and CTA studies. RESULTS: Eight of the 25 linear cardiac dimensional measurements were significantly different between TTE and CTA (p<0.033). Intraobserver agreement was strong with average coefficients of variation (CV) of 5.34% for TTE and 2.50% for CTA. Interobserver agreement CV averaged 6.5% for TTE and 8.75% CTA. Ejection fraction, stroke volume, and end-systolic volume were significantly different between modalities (all p<0.002). No significant difference was present between end-diastolic volume for TTE compared with CTA. DISCUSSION: High-quality cardiac angiographic studies were accomplished using CTA without the use of general anesthesia in English bulldogs. Multi-detector computed tomography angiography and TTE are not interchangeable modalities in the clinical setting. CONCLUSION: Multi-detector-CT ECG-gated cardiac angiography is possible in sedated, non-intubated English bulldogs. Differences were found between some cardiac dimensions as measured by TTE in the awake dog and compared with sedated CTA, indicating the two methodologies are not equivalent. Sedated, non-intubated CTA yielded high-quality imaging with strong intraobserver and interobserver measurement repeatability in English bulldogs.
Assuntos
Angiografia por Tomografia Computadorizada/veterinária , Angiografia Coronária/veterinária , Cães/fisiologia , Ecocardiografia/veterinária , Animais , Feminino , Masculino , Variações Dependentes do Observador , Linhagem , Estudos Prospectivos , Valores de ReferênciaRESUMO
BACKGROUND: The occurrence of lymphocele formation following renal transplantation is variable, and the optimal approach to treatment remains undefined. Opening the peritoneum at the time of transplantation is one method of decreasing the incidence of lymphocele formation. The purpose of this study was to determine whether creating a peritoneal window at the time of transplantation decreases the incidence of lymphocele formation. METHODS: We performed a retrospective review of renal transplants conducted at our institution between 2002 and 2004. Records were reviewed to obtain details regarding opening of the peritoneum at the time of transplant and occurrence of lymphocele. Every patient underwent routine ultrasound imaging in the peri-operative period. Graft dysfunction secondary to the lymphocele was the primary indication for intervention. Data were analyzed by chi-square. RESULTS: During the initial transplant the peritoneum was opened in 35% of patients. The overall incidence of fluid collections, identified by ultrasound, was 24%. Opening the peritoneum did not decrease the incidence of lymphocele. However, more patients with a closed peritoneum required an intervention for a symptomatic lymphocele. In the 11 patients with an open peritoneum and a fluid collection, only one required an intervention. In patients whose peritoneum was left intact, 24% of fluid collections required intervention. Graft survival was equivalent. CONCLUSION: Creating a peritoneal window at the time of transplantation did not decrease the overall incidence of postoperative fluid collections. However, forming a peritoneal window at the time of transplantation did decrease the incidence of symptomatic lymphocele.
Assuntos
Transplante de Rim/métodos , Linfocele/prevenção & controle , Peritônio/cirurgia , Complicações Pós-Operatórias/prevenção & controle , Humanos , Incidência , Linfocele/epidemiologia , Complicações Pós-Operatórias/epidemiologia , Estudos RetrospectivosRESUMO
HYPOTHESIS: Although control of the hepatic vascular pedicle is commonly used during hepatic resection, the optimal method of vascular control continues to be debated. The utility of total or selective vascular isolation, pedicle inflow occlusion, or the absence of vascular isolation during minor and major hepatectomy needs to be examined. DESIGN: Retrospective review of hepatic resections performed for either isolated colorectal or noncolorectal hepatic metastases. SETTING: The University of Chicago Hospitals, Chicago, Ill, a tertiary-care referral center. PATIENTS: One hundred forty-one patients who underwent hepatic resection for isolated metastatic liver disease were identified through The University of Chicago Hospitals Tumor Registry. MAIN OUTCOME MEASURES: Intraoperative parameters, perioperative morbidity and mortality, and tumor recurrence. RESULTS: Four groups were compared with alternative methods of vascular management, including total vascular isolation, Longmire clamping, Pringle maneuver, or no vascular control. Tumor number and size were not significantly different between groups. Blood loss and transfusion requirements tended to be higher in the total vascular isolation group and were significantly higher compared with the Pringle group (P =.06) and the no vascular control group (P =.04), but this also correlated with a higher incidence of complexity of surgical resection. The highest incidence of postoperative complications occurred in the total vascular isolation group (P<.05). With similar permanent pathologic margins, the rates of intrahepatic recurrence were similar among all groups, with the no vascular control group having the lowest recurrence rate. CONCLUSIONS: All methods of vascular control appeared equivalent with respect to limiting blood loss and transfusion requirements while providing adequate surgical margins. The highest rates of blood requirements and complications were noted in the total vascular isolation group, which corresponded to the highest incidence of complex resections. The Longmire clamp group incurred the lowest incidence of complications and resulted in identical surgical margins. The application of vascular control is beneficial to surgeons during hepatic resection, but the method of control should be selected based on the location and complexity of resection required and preference of the individual surgeon.
Assuntos
Perda Sanguínea Cirúrgica/prevenção & controle , Hepatectomia/métodos , Neoplasias Hepáticas/cirurgia , Idoso , Anticoagulantes/uso terapêutico , Constrição , Feminino , Humanos , Tempo de Internação , Fígado/irrigação sanguínea , Neoplasias Hepáticas/irrigação sanguínea , Neoplasias Hepáticas/secundário , Masculino , Pessoa de Meia-Idade , Recidiva Local de NeoplasiaAssuntos
Transplante de Fígado/fisiologia , Complicações Pós-Operatórias/epidemiologia , Doadores de Tecidos/estatística & dados numéricos , Adulto , Peso Corporal , Cardiotônicos/uso terapêutico , Etnicidade , Feminino , Humanos , Illinois , Masculino , Estudos Retrospectivos , Resultado do TratamentoAssuntos
Carcinoma Hepatocelular/diagnóstico por imagem , Neoplasias Hepáticas/diagnóstico por imagem , Transplante de Fígado , Tomografia Computadorizada por Raios X , Adulto , Estudos de Coortes , Humanos , Pessoa de Meia-Idade , Complicações Pós-Operatórias/diagnóstico por imagem , Estudos Retrospectivos , Sensibilidade e EspecificidadeRESUMO
The lower esophageal sphincter (LES) exhibits cyclical phasic contractile activity synchronous with phases II and III of the gastric migrating motor complex. Motilin has been implicated in this process, although the exact mechanism is unknown. The effect of motilin on LES pressure and on gastrointestinal myoelectric activity was examined in 8 unanesthetized opossums. Intraluminal pressure was recorded by a manometric assembly incorporating a sleeve device. Myoelectric activity was recorded from the stomach, duodenum, and jejunum via implanted electrodes. The opossum LES exhibited cyclical periods of phasic contractions synchronous with phases II and III of the gastric migrating motor complex cycle. Variations in the occurrence and magnitude of the phasic LES pressure waves paralleled the spontaneous cyclic fluctuations in the level of circulating plasma motilin. Pulse doses of exogenous motilin (25-400 ng/kg) elicited a contractile LES response that mimicked the spontaneous migrating motor complex-related phasic LES contractions. This effect was dose related with the maximal response occurring at a motilin dose of 100 ng/kg. The LES response to motilin was abolished by hexamethonium and significantly antagonized by atropine and 4-diphenylacetoxy-N-methylpiperidine methiodide, but was not affected by pirenzepine, phentolamine, or naloxone. The study findings support the hypothesis that cyclic increases in circulating endogenous motilin incorporate phasic LES as well as gastric contractile activity into the gastrointestinal migrating motor complex cycle. Motilin acts on the LES by the preganglionic stimulation of cholinergic nerves.
Assuntos
Junção Esofagogástrica/efeitos dos fármacos , Hormônios Gastrointestinais/farmacologia , Motilina/farmacologia , Contração Muscular/efeitos dos fármacos , Gambás/fisiologia , Potenciais de Ação/efeitos dos fármacos , Animais , Relação Dose-Resposta a Droga , Eletromiografia/instrumentação , Eletromiografia/métodos , Junção Esofagogástrica/fisiologia , Jejum , Manometria/instrumentação , Manometria/métodos , Motilina/antagonistas & inibidores , Motilina/sangueRESUMO
The downslope transport of rare earth element-tagged soil particles remobilized during a spring thunderstorm was studied on both a natural prairie and an agricultural field in southwestern Iowa (U.S.A.). A technique was developed for tagging natural soils with the rare earth elements Eu, Tb, and Ho to approximately 1,000 ppm via coprecipitation with MnO2. Tagged material was replaced in target locations; surficial soil samples were collected following precipitation and runoff; and rare earth element concentrations were determined by inductively coupled plasma mass spectrometry. Diffusion and exponential models were applied to the concentration-distance data to determine particle transport distances. The results indicate that the concentration-distance data are well described by the diffusion model, butthe exponential model does not simulate the rapid drop-off in concentrations near the tagged source. Using the diffusion model, calculated particle transport distances at all hillside locations and at both the cultivated and natural prairie sites were short, ranging from 3 to 73 cm during this single runoff event. This study successfully demonstrates a new tool for studying soil erosion.
Assuntos
Metais Terras Raras/análise , Chuva , Poluentes do Solo/análise , Poluentes da Água/análise , Agricultura , Monitoramento Ambiental/métodos , Espectrometria de Massas , Metais Terras Raras/química , Solo , Movimentos da ÁguaRESUMO
In this study, we evaluated the mechanism of action whereby cholecystokinin increases spike-burst rate of the opossum sphincter of Oddi (SO). Each spike burst corresponds to a peristaltic SO contraction. Two types of animal preparations were evaluated: (1) awake chronic animal preparations and (2) anesthetized animals. A total of 19 chronic animals were prepared by implantation of electrodes on the SO, gastric antrum, duodenum, and jejunum. SO spike-burst rate was stimulated by intravenous infusion of CCK-OP (10 ng/kg/min), feeding, or intraduodenal infusion of fat-containing nutrient. Each stimulus was begun 20 min after cessation of phase III duodenal MMC activity and caused an increase in SO spike-burst rate from about 2 to 6/min that lasted for less than or equal to 1 hr. Such increases were antagonized substantially by hexamethonium, atropine, or methysergide. The CCK antagonist, L364718, antagonized the excitatory SO response to CCK-OP infusion or intraduodenal infusion of fat-containing nutrient (Isocal) but did not antagonize the response to feeding; CR1409 had no antagonistic effect on SO response to any of the three types of stimuli. In the acute studies in anesthetized animals, an intravenous bolus dose of CCK-OP (800 ng/kg) caused a substantial increase in SO spike-burst rate that was antagonized by CR1409 but not by atropine, hexamethonium, methysergide, L364718, or TTX.(ABSTRACT TRUNCATED AT 250 WORDS)
Assuntos
Ampola Hepatopancreática/efeitos dos fármacos , Colecistocinina/farmacologia , Contração Muscular/efeitos dos fármacos , Gambás/fisiologia , Esfíncter da Ampola Hepatopancreática/efeitos dos fármacos , Animais , Anti-Hipertensivos/farmacologia , Atropina/farmacologia , Benzodiazepinonas/farmacologia , Colecistocinina/antagonistas & inibidores , Devazepida , Eletrodos Implantados , Alimentos , Hexametônio , Compostos de Hexametônio/farmacologia , Infusões Intravenosas , Metisergida/farmacologiaRESUMO
In this investigation we evaluated the effect of two new cholecystokinin (CCK) antagonists, CR 1409 and L364,718, on gallbladder emptying in the opossum. Gallbladder emptying was elicited by both exogenous and endogenous CCK. The three test challenges were 1) intravenous infusion of CCK octapeptide (OP) (10 ng.kg-1.min-1), 2) feeding, and 3) intraduodenal infusion of Isocal (0.4 ml/min), a fat-containing nutrient. During control conditions each test challenge elicited approximately 60% gallbladder emptying within 30 min and 70% emptying by 60 min. At given doses both CR 1409 and L364,718 substantially antagonized or abolished the gallbladder emptying elicited by each of the test challenges. The antagonism for postprandial gallbladder emptying was diminished between 30 and 50 min compared with that for CCK-OP infusion and intraduodenal infusion of Isocal. Unexpectedly, the gallbladder emptying induced by infusion of motilin (5 micrograms.kg-1.h-1) was antagonized by either CR 1409 or L364,718. In anesthetized animals, gallbladder contraction was induced by a variety of agonists, such as bethanechol, histamine phosphate, 5-hydroxytryptamine, and phenylephrine. In this later model CR 1409 and L364,718 functioned solely as selective antagonists. We conclude that for the opossum gallbladder 1) the CCK antagonists CR 1409 and L364,718 antagonize or abolish gallbladder emptying induced by exogenous or endogenous CCK; 2) the pattern of CCK antagonism after feeding suggests that the early phase of postprandial gallbladder emptying is mediated by a mechanism other than endogenous CCK, whereas late postprandial emptying is mediated by release of endogenous CCK; and 3) CR 1409 and L364,718 are not totally specific antagonists for gallbladder CCK receptors alone but also antagonize gallbladder contraction induced by motilin.(ABSTRACT TRUNCATED AT 250 WORDS)
Assuntos
Benzodiazepinonas/farmacologia , Colecistocinina/antagonistas & inibidores , Vesícula Biliar/fisiologia , Proglumida/análogos & derivados , Sincalida/farmacologia , Animais , Devazepida , Feminino , Vesícula Biliar/efeitos dos fármacos , Vesícula Biliar/inervação , Cinética , Masculino , Gambás , Proglumida/farmacologiaRESUMO
We characterized and quantified a reflex from the pharyngeal mucosa to the upper esophageal sphincter (UES). Seventeen cats were decerebrated, and the pharynx was exposed by opening the cricothyroid ligament. UES motor activity was assessed by recording electromyographic (EMG) activity from the pharyngeal constrictors, i.e., the thyropharyngeus (TP) and cricopharyngeus (CP). The pharyngeal mucosa was stimulated by touch or pressure. Both stimuli activated contraction of the CP primarily when applied to the naso-, laryngo-, or hypopharynx, but pressure was more effective. The anteromedial portion of the hypopharynx was the most sensitive zone, but there was no strong stimulus-response relationship. The reflex response to a 1-s stimulus occurred at a delay of 0.46 +/- 0.06 s and lasted 4.5 +/- 0.5 s. This pharyngo-UES reflex was blocked by anesthesia of the mucosa or transection of the glossopharyngeal or pharyngoesophageal nerves but not the vagus nerves. In contrast, the esophago-UES contractile reflex was not blocked by anesthesia of the pharyngeal mucosa or transection of the glossopharyngeal nerves but was blocked by transection of either the vagus or pharyngoesophageal nerves. We concluded that the pharyngo-UES contractile reflex was activated by pharyngeal mucosal mechanoreceptors whose afferent limb was the glossopharyngeal nerve and whose efferent limb was the pharyngoesophageal branch of the vagus nerve.
Assuntos
Junção Esofagogástrica/fisiologia , Contração Muscular , Faringe/fisiologia , Reflexo , Animais , Gatos , Deglutição , Junção Esofagogástrica/inervação , Feminino , Nervo Glossofaríngeo/fisiologia , Masculino , Mecanorreceptores/fisiologia , Faringe/inervação , Nervo Vago/fisiologiaRESUMO
In conscious opossums, we evaluated the relationship between hepatic bile flow and the intestinal motor function during fasting as well as after feeding. In six opossums, bipolar electrodes were implanted from the gastric antrum to the terminal ileum. After cholecystectomy, the common duct was ligated, and a catheter was tied into the proximal common duct for collecting hepatic bile. During subsequent studies, hepatic bile flow was measured, and bile was returned to the duodenum through an externalized duodenal catheter. Cyclic increases in bile flow during fasting did not show a close correlate with the duodenal migratory motor complex (MMC) cycle. Rather, bile flow showed peak values [0.11 +/- 0.02 (SE) ml/min] when phase III MMC activity reached the midileum. Hepatic bile flow correlated closely with the amount of bile acid secreted by the liver. When the bile acid pool was depleted by diverting bile from the intestine, hepatic secretion of bile fell to uniformly low values of approximately 0.04 ml/min that did not show cyclic variation. Hepatic bile flow after feeding increased to a maximal value of 0.12 +/- 0.01 ml/min at 90 min. We conclude that increases in hepatic bile flow during fasting and after meals are determined mainly by variations in intestinal motor activity that alter small bowel transit and thereby affect the enterohepatic circulation of bile acids.
Assuntos
Bile/metabolismo , Ingestão de Alimentos , Jejum , Fígado/fisiologia , Animais , Ácidos e Sais Biliares/metabolismo , Duodeno/inervação , Músculo Liso/inervação , GambásRESUMO
The present study evaluated the mechanism of cholecystokinin-induced gallbladder contraction in awake opossums. Each of 19 chronic animal preparations had an indwelling gallbladder cannula for monitoring changes in gallbladder volume and a jugular catheter for administration of cholecystokinin octapeptide and drugs. An intraduodenal catheter allowed intraduodenal infusion of Isocal (Mead Johnson Laboratories, Evansville, Ind.). Bipolar electrodes in the stomach, duodenum, and jejunum enabled monitoring of the duodenal migratory myoelectric complex cycle. One-hour infusions of cholecystokinin octapeptide (10 ng/kg/min), intraduodenal Isocal (0.4 ml/min), or feeding were started 20 min after cessation of phase 3 duodenal migratory myoelectric complex activity. Bolus intravenous doses of potential pharmacological antagonists were given 10 min before and 20 min after the onset of cholecystokinin octapeptide infusion, Isocal infusion, or feeding. Each test challenge induced about 60% gallbladder emptying at 30 min and 70% at 60 min. Cholecystokinin octapeptide-induced gallbladder emptying was converted to filling by hexamethonium and nearly abolished by atropine. Similar results were obtained for gallbladder emptying induced by feeding or duodenal infusion of Isocal. Phentolamine caused a modest decrease of cholecystokinin octapeptide-induced gallbladder contraction at 30 min, whereas postprandial or Isocal-induced gallbladder contraction was unaffected. Cholecystokinin octapeptide-induced gallbladder contraction was not affected by pirenzepine, 4-diphenylacetoxy-N-methylpiperidine methiodide, prazosin, pyrilamine, cimetidine, methysergide, naloxone, or propranolol. In acute studies of anesthetized animals, gallbladder contraction induced by a D100 intravenous bolus of cholecystokinin octapeptide (800 ng/kg) was not antagonized by hexamethonium, atropine, or tetrodotoxin. It is concluded (a) that cholecystokinin-induced physiologic contraction of the opossum gallbladder occurs through neural mechanisms rather than by a direct action of cholecystokinin on gallbladder smooth muscle, and (b) that studies using pharmacologic bolus doses of cholecystokinin octapeptide and tetrodotoxin indicate that cholecystokinin receptors exist on the gallbladder smooth muscle which do not seem to have any physiological role in gallbladder emptying.
Assuntos
Vesícula Biliar/efeitos dos fármacos , Contração Muscular/efeitos dos fármacos , Gambás/fisiologia , Sincalida/farmacologia , Animais , Atropina/farmacologia , Interações Medicamentosas , Eletromiografia/instrumentação , Eletromiografia/métodos , Comportamento Alimentar/efeitos dos fármacos , Comportamento Alimentar/fisiologia , Feminino , Alimentos Formulados , Vesícula Biliar/fisiologia , Bloqueadores Ganglionares/farmacologia , Hexametônio , Compostos de Hexametônio/farmacologia , Lipídeos/farmacologia , Masculino , Contração Muscular/fisiologia , Sincalida/sangue , Fatores de TempoRESUMO
Events associated with gastroesophageal reflux have been determined by concurrent diaphragmatic and esophageal body electromyography, video radiography, and manometry in four conscious dogs. Three characteristic phenomena occurred in parallel immediately before and during gastroesophageal reflux: 1) transient lower esophageal sphincter relaxation, 2) profound (99.5%) and selective inhibition of crural diaphragmatic activity, and 3) a previously unrecognized dorsal movement of the gastroesophageal junction (mean 1.3 cm) demonstrated by implanted radiological markers. The patterns associated with spontaneous acid and gas reflux were indistinguishable from those induced by gastric distension. Costolumbar diaphragmatic activity was stable up until the instant of sphincter opening, when there was a single costolumbar contraction of short duration and high amplitude. Esophageal shortening did not occur before reflux. Reflux that occurred after atropine-induced inhibition of lower esophageal sphincter tone to < 2 mmHg was intermittent and coincided with selective crural inhibition. These studies demonstrated that selective crural inhibition is a prerequisite for gastroesophageal reflux and suggest that the crural diaphragm is an important factor for the maintenance of gastroesophageal competence.