RESUMEN
We report the expression of three visual opsins in the retina of the little brown bat (Myotis lucifugus, Vespertilionidae). Gene sequences for a rod-specific opsin and two cone-specific opsins were cloned from cDNA derived from bat eyes. Comparative sequence analyses indicate that the two cone opsins correspond to an ultraviolet short-wavelength opsin (SWS1) and a long-wavelength opsin (LWS). Immunocytochemistry using antisera to visual opsins revealed that the little brown bat retina contains two types of cone photoreceptors within a rod-dominated background. However, unlike other mammalian photoreceptors, M. lucifugus cones and rods are morphologically indistinguishable by light microscopy. Both photoreceptor types have a thin, elongated outer segment. Using microspectrophotometry we classified the absorption spectrum for the ubiquitous rods. Similar to other mammals, bat rhodopsin has an absorption peak near 500 nm. Although we were unable to confirm a spectral range, cellular and molecular analyses indicate that M. lucifugus expresses two types of cone visual pigments located within the photoreceptor layer. This study provides important insights into the visual capacity of a nocturnal microchiropteran species.
Asunto(s)
Quirópteros/metabolismo , Células Fotorreceptoras de Vertebrados/metabolismo , Animales , Anticuerpos/análisis , Anticuerpos/inmunología , Regulación de la Expresión Génica , Humanos , Microespectrofotometría , Opsinas/genética , Opsinas/inmunología , Retina/metabolismoRESUMEN
BACKGROUND: Many individuals with heartburn self-medicate with antacids for relief of their symptoms. AIM: To compare efficacy of effervescent ranitidine to as-needed calcium carbonate antacids in subjects who self-treat heartburn. METHODS: A total of 155 subjects with frequent antacid-responsive heartburn were randomized to receive effervescent ranitidine 150 mg tablets b.d., or as-needed calcium carbonate 750 mg for 12 weeks. Endoscopic oesophagitis severity and mucosal histology were assessed at baseline, and at weeks 6 and 12. Heartburn frequency, severity, and antacid consumption were recorded daily, and quality of life was assessed at baseline, and at weeks 6 and 12. RESULTS: Heartburn frequency and severity were significantly decreased after 1 day of ranitidine (P < 0.02). By week 6, ranitidine had significantly decreased rescue antacid consumption (7.3 tablets, P < 0.001) vs. antacids (14.1 tablets). Endoscopic oesophagitis healing (
Asunto(s)
Pirosis/tratamiento farmacológico , Ranitidina/uso terapéutico , Adulto , Anciano , Antiulcerosos/efectos adversos , Antiulcerosos/uso terapéutico , Esófago de Barrett/tratamiento farmacológico , Carbonato de Calcio/efectos adversos , Carbonato de Calcio/uso terapéutico , Método Doble Ciego , Esofagitis/tratamiento farmacológico , Femenino , Humanos , Masculino , Persona de Mediana Edad , Ranitidina/efectos adversos , Autoadministración , Resultado del TratamientoRESUMEN
BACKGROUND: Many otherwise healthy individuals with episodic heartburn self-medicate with over-the-counter antacids. We evaluated clinical characteristics of subjects who had never been medically diagnosed as having any upper gastrointestinal tract disorder and who used antacids for symptomatic relief of heartburn. SUBJECTS AND METHODS: Subjects with at least 3 months of frequent heartburn relieved by antacids, and with heartburn on at least 4 of 7 days during the week prior to study entry, had their medical history and gastrointestinal pathological characteristics recorded. Tests included esophagogastroduodenoscopy, esophageal motility and sensitivity studies, and 24-hour pH monitoring. RESULTS: Of 178 subjects screened, 13 were excluded on the basis of other gastrointestinal diseases at baseline, including diffuse esophageal spasm, peptic ulcer disease, dysplastic columnar metaplasia of the esophagus (Barrett's esophagus), and adenocarcinoma. Ten subjects were ineligible because of insufficient baseline heartburn. The remaining 155 eligible subjects had heartburn for an average of 11 years. Forty-seven percent had daily symptoms and 70% described heartburn severity as moderate, even though on endoscopy most (53%) had normal-appearing esophageal mucosa (grade 0 or 1). Esophageal acid sensitivity was present in 86% of subjects. Mean lower esophageal sphincter pressures and esophageal contractile amplitudes were at the lower limits of normal and total esophageal acid contact time was slightly increased. CONCLUSIONS: Chronic heartburn can reflect a wide range of diagnostic findings, including important underlying pathological features, and may warrant a full medical examination to detect such abnormal conditions and to permit selection of appropriate therapy.
Asunto(s)
Antiácidos/uso terapéutico , Pirosis/tratamiento farmacológico , Adenocarcinoma/diagnóstico , Adulto , Antiácidos/administración & dosificación , Esófago de Barrett/diagnóstico , Diagnóstico Diferencial , Endoscopía del Sistema Digestivo , Neoplasias Esofágicas/diagnóstico , Espasmo Esofágico Difuso/diagnóstico , Unión Esofagogástrica/fisiopatología , Esófago/fisiopatología , Reflujo Gastroesofágico/diagnóstico , Pirosis/diagnóstico , Pirosis/fisiopatología , Humanos , Concentración de Iones de Hidrógeno , Anamnesis , Membrana Mucosa/fisiopatología , Contracción Muscular/fisiología , Medicamentos sin Prescripción/uso terapéutico , Úlcera Péptica/diagnóstico , Peristaltismo/fisiología , Examen Físico , Presión , Automedicación , Sensación/fisiología , Índice de Severidad de la EnfermedadRESUMEN
BACKGROUND: Ranitidine 150 mg q.d.s. is the currently recommended dosage in the United States for the treatment of erosive oesophagitis. To determine whether a higher dose of ranitidine administered less frequently would also be effective in healing erosive oesophagitis, we compared ranitidine 300 mg b.d. with ranitidine 150 mg q.d.s. in the treatment of erosive oesophagitis. METHODS: This multicentre, double-blind, randomized, placebo-controlled study conducted in the United States compared two dosages of ranitidine in 772 patients with endoscopically diagnosed erosive oesophagitis. Patients were treated with ranitidine 300 mg b.d., ranitidine 150 mg q.d.s. or placebo for up to 12 weeks. Endoscopies were repeated after 4, 8 and 12 weeks of treatment. RESULTS: Ranitidine 300 mg b.d. was significantly more effective than placebo in healing erosive oesophagitis at weeks 8 and 12 (51 vs. 36% and 66 vs. 52%, respectively; P < or = 0.004). Significantly higher healing rates were also achieved with ranitidine 150 mg q.d.s. compared with placebo at 4, 8 and 12 weeks (37 vs. 21%, 62 vs. 36% and 77 vs. 52%, respectively; P < 0.001). Healing rates were significantly higher with ranitidine 150 mg q.d.s. than with ranitidine 300 mg b.d. at all scheduled endoscopies (P < or = 0.041). CONCLUSIONS: Ranitidine 300 mg b.d. is effective in healing erosive oesophagitis and may be appropriate as an alternative dosage regimen to ranitidine 150 mg q.d.s. in some patients with erosive oesophagitis.
Asunto(s)
Antiulcerosos/administración & dosificación , Antiulcerosos/uso terapéutico , Esofagitis/tratamiento farmacológico , Ranitidina/administración & dosificación , Ranitidina/uso terapéutico , Adulto , Anciano , Antiácidos/administración & dosificación , Antiácidos/uso terapéutico , Método Doble Ciego , Esofagitis/patología , Femenino , Pirosis/tratamiento farmacológico , Humanos , Masculino , Persona de Mediana EdadRESUMEN
In order to compare the processes of restenosis after balloon angioplasty as compared to that after directional coronary atherectomy, we performed qualitative and quantitative analysis of 72 lesions in 68 patients with recurrent ischemia following a successful initial procedure. For each lesion, we reviewed the pre-intervention, immediate post-intervention, and restenosis angiograms. The morphology of the restenotic lesions could not be predicted from pre- or post-intervention angiograms. The restenotic lesions after directional atherectomy, as compared to balloon angioplasty, did not show a statistically significant difference, although there was a trend to more eccentric narrowing.
Asunto(s)
Angioplastia Coronaria con Balón , Aterectomía Coronaria , Angiografía Coronaria , Enfermedad Coronaria/terapia , Anciano , Enfermedad Coronaria/diagnóstico por imagen , Femenino , Humanos , Masculino , Persona de Mediana Edad , Recurrencia , Factores de Riesgo , Resultado del TratamientoRESUMEN
OBJECTIVE: To derive and validate a clinical prediction rule that identifies patients after myocardial infarction who have preserved left ventricular systolic function. DESIGN: Retrospective analysis of a prospective cohort study, with a derivation set to generate a clinical prediction rule and a validation set to test the prediction rule. SETTING: Urban tertiary care hospital. PATIENTS: 314 consecutive patients admitted with myocardial infarction who had one or more of the following tests to determine left ventricular ejection fraction: transthoracic echocardiography, contrast left ventriculography, or radionuclide ventriculography. MEASUREMENTS: Left ventricular ejection fractions were determined by transthoracic echocardiography, contrast left ventriculography, and gated blood pool scan. RESULTS: Multivariate analysis of patients in the derivation set yielded the following rule: The left ventricular ejection fraction is predicted to be 40% or more in patients who have 1) an interpretable electrocardiogram, 2) no previous Q-wave myocardial infarction, 3) no history of congestive heart failure, and 4) an index myocardial infarction that is not a Q-wave anterior infarction. In the derivation and the validation sets, the positive predictive value of the prediction rule was more than 0.98. CONCLUSIONS: A simple clinical prediction rule using easily obtained historical and electrocardiographic data reliably identifies a substantial percentage of patients after myocardial infarction (40% in our hospital) who are likely to have preserved left ventricular systolic function. If validated in other patient populations, application of this prediction rule in clinical practice could result in a substantial decrease in the cost of treating uncomplicated myocardial infarction.
Asunto(s)
Infarto del Miocardio/fisiopatología , Volumen Sistólico/fisiología , Función Ventricular Izquierda/fisiología , Anciano , Protocolos Clínicos , Ecocardiografía , Electrocardiografía , Femenino , Humanos , Masculino , Ventriculografía con Radionúclidos , Estudios RetrospectivosRESUMEN
Right ventricular (RV) infarction is a well-recognized complication of some acute inferior myocardial infarctions. Recently, there have been numerous case reports of RV infarctions complicated by severe refractory hypoxemia secondary to right-to-left shunting through a patent foramen ovale. An additional case missed by transthoracic echocardiography and cardiac catheterization is reported and the English literature on the subject is reviewed.
Asunto(s)
Defectos del Tabique Interatrial/complicaciones , Hipoxia/fisiopatología , Infarto del Miocardio/fisiopatología , Anciano , Ecocardiografía Transesofágica , Femenino , Ventrículos Cardíacos/fisiopatología , Humanos , Hipoxia/etiologíaRESUMEN
Two ranitidine dosages were compared for the treatment of erosive esophagitis in a multicenter, double-blind, randomized, parallel-group, placebo-controlled study. Adults with endoscopically verified erosive esophagitis were treated with either ranitidine 150 mg four times daily (n = 106), ranitidine 300 mg four times daily (n = 106), or placebo (n = 116) for up to 12 wk. Patients were also encouraged to adhere to lifestyle modifications (e.g., to elevate the head of bed, etc). Erosive esophagitis healing, determined by endoscopy, was achieved in 69% and 62% of ranitidine-treated patients by 8 wk and in 79% and 74% by 12 wk (150 mg and 300 mg, respectively) compared with 28% of placebo-treated patients by 8 wk and 40% by 12 wk (p < 0.001 ranitidine vs. placebo). Onset of heartburn relief occurred within 24 h of initiating either ranitidine dosage, and relief was maintained throughout the 12-wk study. Both ranitidine dosages displayed safety profiles similar to that of placebo. We conclude that ranitidine 150 mg or 300 mg administered four times daily is effective for healing erosive esophagitis and relieving its symptoms.
Asunto(s)
Esofagitis/tratamiento farmacológico , Ranitidina/administración & dosificación , Método Doble Ciego , Femenino , Humanos , Estilo de Vida , Masculino , Persona de Mediana EdadRESUMEN
The immunotoxicity of methyl isocyanate (MIC) was evaluated in female B6C3F1 mice exposed via inhalation to 0, 1, or 3 ppm for 6 hr per day on 4 consecutive days. The antibody response to sheep erythrocytes and natural killer cell activity were found to be unaffected by MIC exposure. Although lymphoproliferative responses to mitogens were moderately suppressed by MIC, the differences were not statistically significant. The response of splenic lymphocytes to allogeneic leukocytes in a mixed leukocyte response (MLR) was suppressed in a dose-related fashion and was significantly different from the control response at the 3 ppm level. This effect was thought to be secondary and a result of general toxicity, rather than a direct effect of MIC on the immune system. Furthermore, resistance to the infectious agents Listeria monocytogenes, mouse malaria parasite, and influenza virus, or to transplantable tumor cells was not compromised by MIC exposure. Thus, the immune system does not appear to be a primary target for MIC toxicity.
Asunto(s)
Cianatos/toxicidad , Sistema Inmunológico/efectos de los fármacos , Isocianatos , Animales , Formación de Anticuerpos/efectos de los fármacos , Cianatos/administración & dosificación , Citotoxicidad Inmunológica/efectos de los fármacos , Femenino , Células Asesinas Naturales/efectos de los fármacos , Activación de Linfocitos/efectos de los fármacos , Prueba de Cultivo Mixto de Linfocitos , RatonesRESUMEN
The effects of methyl isocyanate (MIC) on systemic immunity were evaluated in female B6C3F1 mice exposed via inhalation to 0, 1, or 3 ppm for 6 hr per day on four consecutive days. Humoral immunity, measured as the antibody response to sheep erythrocytes, and natural killer cell activity were not affected by MIC. Furthermore, resistance to the infectious agents Listeria monocytogenes, mouse malaria parasite, and influenza virus, or to B16F10 transplantable tumor cells, was not compromised by MIC exposure. Although lymphoproliferative responses to mitogens were not significantly suppressed, the response of splenic lymphocytes to allogeneic leukocytes in a mixed leukocyte response (MLR) was suppressed in a dose-related fashion and differed significantly from the control response at the 3-ppm level. These studies indicate that MIC exposure in mice does not severely alter systemic immunity. The moderate changes detected in immune function may be a secondary consequence of respiratory toxicity which occurred in these animals.
Asunto(s)
Cianatos/inmunología , Isocianatos , Pulmón/efectos de los fármacos , Animales , Formación de Anticuerpos/efectos de los fármacos , Cámaras de Exposición Atmosférica , Femenino , Técnica de Placa Hemolítica , Células Asesinas Naturales/efectos de los fármacos , Pulmón/inmunología , RatonesRESUMEN
It was recently reported that suppression of murine bone marrow hematopoiesis is a very sensitive indicator for 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) toxicity (1). We report here that a structural analog of TCDD, 1-NH2-3,7,8-trichlorodibenzo-p-dioxin (NH2-TriCDD), is a specific and effective antagonist for TCDD-induced myelotoxicity and enzyme induction. When administered to mice or added directly into culture at a 100-fold excess, relative to TCDD, NH2-TriCDD completely abrogated the ability of TCDD to inhibit granulocyte-macrophage progenitor cells (CFU-C) formation, an indicator of hematopoiesis. Further, NH2-TriCDD inhibited TCDD-induced activation of cytochrome P1-450 monooxygenase activity. Studies designed to measure specific binding of TCDD to the cytosolic Ah receptor indicated that NH2-TriCDD effectively inhibited binding of TCDD to the receptor by acting as a competitive antagonist (Ki = 0.72 nM).