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1.
J Clin Oncol ; 5(7): 1078-82, 1987 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-3598611

RESUMEN

We conducted parallel phase II trials of cimetidine as a single agent and the combination N-phosphonacetyl-L-aspartate (PALA) plus L-alanosine among 40 previously untreated patients with biopsy-proven, measurable disseminated malignant melanoma. We did not design the trial to be a comparative assessment of the two regimens. Among 19 patients treated with cimetidine, 300 mg orally four times daily, there was one complete response of extensive pleural and pulmonary metastases for 16+ months and two partial regressions of soft tissue lesions for 7 and 21+ months, respectively. Among 21 patients treated with the combination regimen, there was only one partial response in soft tissue for 1 month. The median times to progression and death were 1.4 and 6 months, respectively, for cimetidine, and 1.3 and 4 months, respectively, from the combination of PALA plus L-alanosine. Among patients who progressed on initial treatment, there were no responses in 12 who received crossover therapy with cimetidine and 11 with the combination regimen. Two patients treated with the combination program had severe stomatitis, two developed renal failure, and one had severe leukopenia and thrombocytopenia. Recognizing the limitations of small sample size, these early observations suggest that cimetidine may have intriguing implications in the management of disseminated malignant melanoma.


Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Cimetidina/uso terapéutico , Melanoma/tratamiento farmacológico , Alanina/administración & dosificación , Alanina/análogos & derivados , Ácido Aspártico/administración & dosificación , Ácido Aspártico/análogos & derivados , Evaluación de Medicamentos , Femenino , Humanos , Neoplasias Pulmonares/tratamiento farmacológico , Neoplasias Pulmonares/secundario , Masculino , Melanoma/secundario , Persona de Mediana Edad , Ácido Fosfonoacético/administración & dosificación , Ácido Fosfonoacético/análogos & derivados , Neoplasias Pleurales/tratamiento farmacológico , Neoplasias Pleurales/secundario , Neoplasias de los Tejidos Blandos/tratamiento farmacológico , Neoplasias de los Tejidos Blandos/secundario
2.
J Clin Oncol ; 11(4): 762-7, 1993 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-8478668

RESUMEN

PURPOSE: Several placebo-controlled randomized clinical trials have demonstrated that megestrol acetate can result in appetite stimulation and nonfluid weight gain in patients with cancer anorexia/cachexia. The present trial was designed to compare megestrol acetate doses ranging from 160 to 1,280 mg/d. METHODS: This trial randomized 342 assessable patients with cancer anorexia/cachexia to receive oral megestrol acetate at doses of 160, 480, 800, or 1,280 mg/d. Patients were evaluated monthly by history, examination, patient-completed questionnaires, and serum albumin levels. RESULTS: The data demonstrate that there is a positive dose-response effect for megestrol acetate on appetite stimulation (P < or = .02). In concert, there was a trend for more nonfluid weight gain with higher drug doses. Megestrol acetate was well tolerated in this group of patients with advanced malignant disease. CONCLUSION: The positive dose-response effect that we observed for megestrol acetate on appetite stimulation supports both our prestudy hypothesis and other available literature. Nonetheless, based primarily on the cost and inconvenience associated with the use of higher doses of this drug, it is reasonable to use 160 mg/d for the initial treatment of cancer anorexia/cachexia in routine clinical practice.


Asunto(s)
Anorexia/tratamiento farmacológico , Caquexia/tratamiento farmacológico , Megestrol/análogos & derivados , Neoplasias/complicaciones , Adulto , Anciano , Anciano de 80 o más Años , Anorexia/etiología , Apetito/efectos de los fármacos , Caquexia/etiología , Relación Dosis-Respuesta a Droga , Ingestión de Alimentos/efectos de los fármacos , Femenino , Humanos , Masculino , Megestrol/administración & dosificación , Megestrol/efectos adversos , Acetato de Megestrol , Persona de Mediana Edad , Estudios Prospectivos , Aumento de Peso/efectos de los fármacos
3.
J Clin Oncol ; 13(11): 2776-83, 1995 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-7595738

RESUMEN

PURPOSE: We conducted a randomized prospective trial in selected patients with fully resected high-risk stage I and II malignant melanoma. PATIENTS AND METHODS: Interferon alfa-2a (IFN-alpha 2a) 20 x 10(6) U/m2 was administered three times each week for 12 weeks by the intramuscular route. Both the treatment group (n = 131) and the control group (n = 131) were evenly balanced with regard to relevant prognostic discriminants. RESULTS: The median disease-free survival (DFS) time was 2.4 years for the IFN-alpha 2a group and 2.0 years for the observation group (log-rank P = 0.19). The median survival times were 6.6 years for IFN-alpha 2a and 5.0 years for observation (log-rank P = .40). For stage I patients (n = 102), there was no apparent therapeutic advantage from IFN-alpha 2a therapy. The DFS for stage II patients was a median of 10.8 months in the control group versus 17 months in the treatment group. The overall survival time was 4.1 years for the treatment group versus 2.7 years for the control group. The differences in DFS for stage II patient were significant in a Cox model. These results must be interpreted cautiously because of subset analysis. A severe flu-like toxicity occurred in 44% of patients, 13% lost at least 10% of their baseline weight, and 45% experienced a worsening of Eastern Cooperative Oncology Group (ECOG) performance score. CONCLUSION: Our findings indicate trends that suggest a possible benefit for selected patients with high-risk malignant melanoma. The results will require further study in a larger patient population for confirmation.


Asunto(s)
Interferón-alfa/uso terapéutico , Melanoma/terapia , Neoplasias Cutáneas/terapia , Adulto , Anciano , Anciano de 80 o más Años , Canadá , Distribución de Chi-Cuadrado , Terapia Combinada , Supervivencia sin Enfermedad , Femenino , Humanos , Interferón alfa-2 , Masculino , Melanoma/mortalidad , Melanoma/cirugía , Persona de Mediana Edad , Recurrencia Local de Neoplasia , Estudios Prospectivos , Proteínas Recombinantes , Neoplasias Cutáneas/mortalidad , Neoplasias Cutáneas/cirugía , Tasa de Supervivencia , Estados Unidos
4.
J Clin Oncol ; 16(9): 2953-8, 1998 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-9738563

RESUMEN

PURPOSE: Previous investigators have reported responses in 52% of patients treated with mechlorethamine (nitrogen mustard), vincristine, and procarbazine (MOP) for recurrent glioma. To confirm these promising results, we conducted a phase II prospective study. PATIENTS AND METHODS: Sixty-three patients with histologic confirmation of recurrent glioma were treated with the MOP regimen. Patients with or without prior chemotherapy received nitrogen mustard 3 mg/m2 or 6 mg/m2, respectively, intravenously on days 1 and 8 plus vincristine 2 mg/m2 intravenously on days 1 and 8, and procarbazine 100 mg/m2 orally on days 1 to 14. Cycles were repeated every 28 days. RESULTS: Of 61 patients assessable for response, eight responded (13%), with one complete response (CR). Responses were as follows: low-grade gliomas, 19%; anaplastic astrocytomas, 11%; anaplastic oligodendrogliomas or oligoastrocytomas, 25%; and glioblastomas, 4.3%. The most common toxicity was myelosuppression with leukocyte nadirs less than 1,000/microL in 23% and platelet nadirs less than 25,000/microL in 13% of patients. Two patients died of infection in the setting of neutropenia. Nonhematologic toxicity included neurosensory changes in 21% of patients (severe in 3%) and severe dermatologic reactions in 8%. In multivariate analysis, Eastern Cooperative Oncology group (ECOG) performance status (PS) was the best predictor for response to chemotherapy (P=.01) and time to progression (P=.008), while PS and grade were the most important predictors of survival (P=.002 and .05, respectively). CONCLUSION: This study did not confirm the high response rate previously reported in recurrent gliomas. Patients with recurrent anaplastic oligodendrogliomas or oligoastrocytomas and recurrent low-grade gliomas had the highest response rates (25% and 19%, respectively). In multivariate analysis, ECOG PS was the best predictor of response, while PS and tumor grade were the most important predictors of survival.


Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Neoplasias Encefálicas/tratamiento farmacológico , Glioma/tratamiento farmacológico , Recurrencia Local de Neoplasia/tratamiento farmacológico , Adulto , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Astrocitoma/tratamiento farmacológico , Femenino , Humanos , Masculino , Mecloretamina/administración & dosificación , Mecloretamina/efectos adversos , Persona de Mediana Edad , Oligodendroglioma/tratamiento farmacológico , Procarbazina/administración & dosificación , Procarbazina/efectos adversos , Estudios Prospectivos , Análisis de Supervivencia , Vincristina/administración & dosificación , Vincristina/efectos adversos
5.
Cancer Epidemiol Biomarkers Prev ; 5(5): 371-4, 1996 May.
Artículo en Inglés | MEDLINE | ID: mdl-9162303

RESUMEN

This intergroup trial was developed to determine the toxicity of relatively low doses of difluoromethylornithine (DFMO) administered to humans for 1 year. The goal was to find an appropriate DFMO dose for use in human chemoprevention trials. Patients with resected superficial bladder cancers were studied. Following stratification, they were randomized to daily DFMO doses of 0.125, 0.25, 0.5, or 1.0 g/day for a planned period of 1 year. Patients were followed closely for evidence of drug toxicity. Seventy-six patients were evenly randomized (19 per group) to receive each dose of DFMO. Forty-nine patients received DFMO for more than 200 days while 35 received the drug for > or = 350 days. No substantial drug-related toxicity was observed at any dose. DFMO doses of > or = 1 g/day for periods up to 1 year appear to be without significant toxicity in most patients. This dose range may be appropriate for use in future human cancer chemoprevention trials.


Asunto(s)
Antineoplásicos/administración & dosificación , Carcinoma de Células Transicionales/prevención & control , Eflornitina/administración & dosificación , Neoplasias de la Vejiga Urinaria/prevención & control , Antineoplásicos/efectos adversos , Carcinoma de Células Transicionales/cirugía , Quimioprevención , Relación Dosis-Respuesta a Droga , Evaluación de Medicamentos , Eflornitina/efectos adversos , Femenino , Estudios de Seguimiento , Trastornos de la Audición/inducido químicamente , Humanos , Masculino , Persona de Mediana Edad , Náusea/inducido químicamente , Recurrencia Local de Neoplasia/prevención & control , Neoplasias de la Vejiga Urinaria/cirugía , Vómitos/inducido químicamente
6.
Int J Radiat Oncol Biol Phys ; 35(2): 299-303, 1996 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-8635937

RESUMEN

PURPOSE: A randomized clinical trial from Great Britain suggested a possible beneficial effect of acetylsalicylate in the prevention of radiation-induced bowel toxicity. Olsalazine is an orally administered drug designed to deliver 5-aminosalicylate to the large bowel with minimal systemic absorption. A randomized clinical trial was undertaken to assess the effectiveness of olsalazine in preventing acute diarrhea in patients receiving pelvic radiation therapy. METHODS AND MATERIALS: Patients receiving pelvic radiation therapy were randomized, in double-blind fashion, to olsalazine 250 mg, two capsules twice daily, or an identical appearing placebo, two capsules twice daily. Patients were then evaluated weekly during radiation therapy for the primary study endpoint, diarrhea, as well as rectal bleeding, abdominal cramping, and tenesmus. RESULTS: The study was closed early, after entry of 58 evaluable patients, when a preliminary analysis showed excessive diarrhea in patients randomized to olsalazine. The incidence and severity of diarrhea were worse in patients randomized to olsalazine (p = 0.0036). Sixty percent of the patients randomized to olsalazine experienced Grade 3 or 4 diarrhea compared to only 14% randomized to placebo. There was also a trend toward higher incidence and greater severity of abdominal cramping in patients who were randomized to olsalazine (p = 0.084). CONCLUSION: Administration of olsalazine during pelvic radiation therapy resulted in an increased incidence and severity of diarrhea. Olsalazine is contraindicated in patients receiving pelvic radiation therapy.


Asunto(s)
Ácidos Aminosalicílicos , Diarrea/prevención & control , Neoplasias Pélvicas/radioterapia , Anciano , Contraindicaciones , Defecación/efectos de los fármacos , Diarrea/inducido químicamente , Diarrea/epidemiología , Método Doble Ciego , Esquema de Medicación , Femenino , Humanos , Incidencia , Masculino , Espasmo/inducido químicamente
7.
Mayo Clin Proc ; 71(6): 552-5, 1996 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-8642883

RESUMEN

OBJECTIVE: To characterize a clinical syndrome that occurs in some women who have undergone breast or axillary lymph node biopsy or partial mastectomy. MATERIAL AND METHODS: Six case reports are presented, the clinical and histopathologic findings are described, and the implications for recognition of this entity are discussed. RESULTS: Patients who had undergone partial mastectomy, breast biopsy, or axillary lymph node excision shortly thereafter had clinical signs (most notably, erythema and edema) suggestive of infectious mastitis or inflammatory breast cancer. Representative histologic sections of involved skin revealed dilated dermal vessels without specific evidence of infection or cancer. Although antibiotic therapy was generally ineffective, the clinical findings resolved with time (from 2 months to 1 year). This condition should be considered in the differential diagnosis when this circumscribed patient population has such intervention-related symptoms. CONCLUSION: This clinical syndrome may mimic an infectious or neoplastic process, but we hypothesize that it is due to interruption of lymphatic vessels. Appropriate recognition may alter the use of antibiotic therapy or surgical intervention.


Asunto(s)
Adenocarcinoma/cirugía , Neoplasias de la Mama/cirugía , Complicaciones Posoperatorias , Adenocarcinoma/patología , Anciano , Axila , Biopsia , Neoplasias de la Mama/patología , Femenino , Humanos , Ganglios Linfáticos/patología , Mastectomía Radical Modificada , Mastectomía Segmentaria , Mastitis/diagnóstico , Persona de Mediana Edad
8.
Int J Epidemiol ; 8(2): 177-9, 1979 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-528114

RESUMEN

An independent study programme (ISP) was devised to permit self-paced learning in a combined epidemiology and biostatistics course for second-year medical students. The ISP was offered as an alternative to lecture instruction and the enrolment was restricted to 40 students out of a class of 176. The students who selected the ISP were superior to the remainder of the class with regard to MCAT scores and performance in first-year subjects. The ISP group scored higher on the examinations given in the course, including a set of 35 final examination questions which were identical for all students. This difference persisted even when the scores were adjusted for ability by use of MCAT scores. The time taken to complete the ISP varied considerably and there was no correlation between completion time and performance. Almost all the ISP students indicated satisfaction with the course and expressed a desire to have a similar option in subsequent courses.


Asunto(s)
Epidemiología/educación , Estadística como Asunto , Educación de Pregrado en Medicina , Evaluación Educacional
9.
J Appl Physiol (1985) ; 79(5): 1679-86, 1995 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-8594029

RESUMEN

Stimulation of vagal pulmonary C-fiber afferents by chemical irritants is believed to be responsible for eliciting the pulmonary chemoreflex (apnea, bradycardia, and hypotension). This study was carried out in anesthetized Sprague-Dawley rats to determine whether the pulmonary chemoreflex was altered by prostaglandin E2 (PGE2), which is one of the major inflammatory mediators in the lungs and is known to enhance the sensitivity of C-fiber afferents in several other organ systems. Capsaicin injected at a dose just above the stimulation threshold (0.25 or 0.5 microgram/kg i.v.) elicited a very mild respiratory and cardiovascular depression. In sharp contrast, during a constant infusion of PGE2 (1.5 micrograms.kg-1.min-1 i.v.), the same dose of capsaicin triggered a long apnea, with the expiratory duration reaching 843% of the baseline expiratory duration, accompanied by intense bradycardia and hypotension. Similarly, the pulmonary chemoreflex response elicited by a bolus injection of phenyl biguanide (1 or 2 micrograms/kg i.v.) was also greatly augmented by PGE2. These enhanced responses were completely abolished, by a perineural capsaicin treatment of both cervical vagi to selectively block the conduction of C fibers, suggesting the involvement of these afferents. Electrophysiological recording of pulmonary C-fiber afferent activity further supported our conclusion that the sensitivity of these sensory endings to capsaicin challenge was potentiated by PGE2.


Asunto(s)
Células Quimiorreceptoras/efectos de los fármacos , Dinoprostona/farmacología , Pulmón/inervación , Fibras Nerviosas/efectos de los fármacos , Nervio Vago/efectos de los fármacos , Análisis de Varianza , Animales , Biguanidas/farmacología , Capsaicina/farmacología , Células Quimiorreceptoras/fisiología , Femenino , Hipoglucemiantes/farmacología , Pulmón/efectos de los fármacos , Pulmón/fisiología , Masculino , Ratas , Ratas Sprague-Dawley
10.
J Appl Physiol (1985) ; 74(1): 333-8, 1993 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-8444711

RESUMEN

To determine whether the irritant effect of cigarette smoke on breathing was affected by chronic exposure to smoke, two groups of sixteen young male Sprague-Dawley rats were exposed daily to fresh cigarette smoke (treated group) or air (control group) for 4-8 wk. Acute ventilatory response to cigarette smoke (50% concn, 6 ml volume) inhaled via a tracheal cannula was then studied under anesthesia and compared between the two groups. Inhalation of either cigarette smoke or gas phase smoke induced an immediate and transient apnea or bradypnea that was completely abolished by bilateral vagotomy in both groups, suggesting the involvement of vagal bronchopulmonary afferents. However, the apneic response was markedly attenuated in the treated group. Inhalation of cigarette smoke, but not the gas phase smoke, also induced a delayed tachypneic response after the initial apnea. The tachypneic response was again significantly smaller in treated rats, and this difference between the two groups was eliminated after vagotomy. On the basis of these results, we suggest that a reduced stimulatory effect on vagal bronchopulmonary sensory receptors was responsible for the attenuated ventilatory responses to smoke observed in treated rats.


Asunto(s)
Mecánica Respiratoria/fisiología , Fumar/fisiopatología , Anestesia , Animales , Apnea/fisiopatología , Carboxihemoglobina/metabolismo , Mediciones del Volumen Pulmonar , Masculino , Ratas , Ratas Sprague-Dawley , Factores de Tiempo , Vagotomía
11.
J Appl Physiol (1985) ; 72(3): 1050-6, 1992 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-1568959

RESUMEN

Spontaneous inhalation of acrolein vapor (350 ppm, 1 ml/100 g body wt) elicited an immediate and transient inhibitory effect on breathing in anesthetized rats, characterized by a prolongation of expiratory duration and accompanied by a bradycardia; ventilation was reduced by 47 +/- 6%, which returned to baseline after three to seven breaths. When both vagi were cooled to 6.6 +/- 0.1 degrees C, the reflex apneic response to lung inflation was completely abolished but the bradypneic response to acrolein was not affected. After perineural capsaicin treatment of both cervical vagi to selectively block the capsaicin-sensitive C-fiber afferents, acrolein no longer evoked an inhibitory effect on breathing; conversely, an augmented inspiration was consistently elicited with the first breath of acrolein inhalation, which was subsequently abolished by cooling both vagi to 6.5 degrees C. The inhibitory effect of inhaling acrolein at a lower concentration (200 ppm) was not detectable, whereas that of a higher concentration (600 ppm) was more intense and prolonged. All these responses were completely eliminated by bilateral vagotomy. These results suggest that inhaled acrolein activated both vagal C-fiber endings and rapidly adapting irritant receptors in the airways, but the acrolein-induced inhibitory effect on breathing was elicited primarily by the C-fiber afferent stimulation.


Asunto(s)
Acroleína/toxicidad , Respiración/efectos de los fármacos , Nervio Vago/efectos de los fármacos , Acroleína/administración & dosificación , Vías Aferentes/efectos de los fármacos , Vías Aferentes/fisiología , Animales , Capsaicina/farmacología , Frío , Relación Dosis-Respuesta a Droga , Femenino , Pulmón/efectos de los fármacos , Pulmón/patología , Pulmón/fisiopatología , Masculino , Fibras Nerviosas/efectos de los fármacos , Fibras Nerviosas/fisiología , Ratas , Ratas Endogámicas , Reflejo/efectos de los fármacos , Reflejo/fisiología , Respiración/fisiología , Nervio Vago/fisiología
12.
J Appl Physiol (1985) ; 83(3): 958-65, 1997 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-9292485

RESUMEN

Acute exposure to ozone (O3) induces airway hyperresponsiveness to various inhaled bronchoactive substances. Inhalation of cigarette smoke, a common inhaled irritant in humans, is known to evoke a transient bronchoconstrictive effect. To examine whether O3 increases airway responsiveness to cigarette smoke, effects of smoke inhalation challenge on total pulmonary resistance (RL) and dynamic lung compliance (Cdyn) were compared before and after exposure to O3 (1.5 ppm, 1 h) in anesthetized guinea pigs. Before O3 exposure, inhalation of two breaths of cigarette smoke (7 ml) at a low concentration (33%) induced a mild and reproducible bronchoconstriction that slowly developed and reached its peak (DeltaRL = 67 +/- 19%, DeltaCdyn = -29 +/- 6%) after a delay of >1 min. After exposure to O3 the same cigarette smoke inhalation challenge evoked an intense bronchoconstriction that occurred more rapidly, reaching its peak (DeltaRL = 620 +/- 224%, DeltaCdyn = -35 +/- 7%) within 20 s, and was sustained for >2 min. By contrast, sham exposure to room air did not alter the bronchomotor response to cigarette smoke challenge. Pretreatment with CP-99994 and SR-48968, the selective antagonists of neurokinin type 1 and 2 receptors, respectively, completely blocked the enhanced responses of RL and Cdyn to cigarette smoke challenge induced by O3. These results show that O3 exposure induces airway hyperresponsiveness to inhaled cigarette smoke and that the enhanced responses result primarily from the bronchoconstrictive effect of endogenous tachykinins.


Asunto(s)
Hiperreactividad Bronquial/inducido químicamente , Ozono/toxicidad , Taquicininas/fisiología , Contaminación por Humo de Tabaco/efectos adversos , Acetilcolina/administración & dosificación , Acetilcolina/farmacología , Animales , Presión Sanguínea/efectos de los fármacos , Presión Sanguínea/fisiología , Bronquios/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Cobayas , Masculino , Músculo Liso/efectos de los fármacos , Antagonistas del Receptor de Neuroquinina-1 , Receptores de Neuroquinina-2/antagonistas & inhibidores , Mecánica Respiratoria/efectos de los fármacos , Mecánica Respiratoria/fisiología , Sustancia P/antagonistas & inhibidores , Sustancia P/fisiología
13.
J Appl Physiol (1985) ; 81(6): 2349-57, 1996 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-9018478

RESUMEN

Experiments were carried out to characterize the cardiorespiratory reflex responses to intravenous injection of lactic acid and to determine the involvement of vagal bronchopulmonary C-fiber afferents in eliciting these responses in anesthetized rats. Bolus injection of lactic acid (0.2 mmol/kg i.v.) immediately elicited apnea, bradycardia, and hypotension, which were then followed by a sustained hyperpnea. The immediate apneic and bradycardiac responses to lactic acid were completely abolished by bilateral vagotomy and were absent when the same dose of lactic acid was injected into the left ventricle. The subsequent hyperpneic response was substantially attenuated by denervation of carotid body chemoreceptors. After a perineural capsaicin treatment of both vagus nerves to block the conduction of C fibers, lactic acid no longer evoked the immediate apnea and bradycardia, whereas the hyperpneic response became more pronounced and sustained, presumably because of the removal of the inhibitory effect on breathing mediated by pulmonary C-fiber activation. Single-unit electrophysiological recording showed that intravenous injection of lactic acid consistently evoked an abrupt and intense burst of discharge from the vagal C-fiber afferent endings in the lungs. In conclusion, the cardiorespiratory depressor responses induced by lactic acid are predominantly elicited by activation of vagal pulmonary C fibers.


Asunto(s)
Ácido Láctico/farmacología , Reflejo/efectos de los fármacos , Respiración/efectos de los fármacos , Nervio Vago/efectos de los fármacos , Animales , Femenino , Inyecciones Intravenosas , Masculino , Ratas , Ratas Sprague-Dawley
14.
J Appl Physiol (1985) ; 84(2): 417-24, 1998 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-9475846

RESUMEN

The clinical use of adenosine is commonly associated with pulmonary side effects, namely dyspnea, that suggest the possible involvement of bronchopulmonary sensory afferents. Our objective in this study was to characterize the effects of adenosine on breathing and to determine whether the vagal pulmonary afferents play a role in mediating these effects. We measured respiratory and cardiovascular changes in anesthetized, spontaneously breathing rats after bolus injections of adenosine at therapeutic doses. Right atrial injection of adenosine (0.04-0.6 mg/kg) elicits, in a dose-dependent manner, a pulmonary chemoreflex-like response consisting of a delayed apnea, bradycardia, and hypotension. In contrast, the classic capsaicin-elicited pulmonary chemoreflex occurs immediately after injection. Perineural capsaicin treatment of the cervical vagi blocked the adenosine-induced respiratory inhibition. Left ventricular administration of adenosine failed to elicit an apneic response. Pretreatment with the adenosine A1-receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine attenuated the adenosine-induced apnea. These results indicate that adenosine elicits a respiratory inhibition via stimulation of pulmonary C fibers and that activation of the A1-receptor is probably involved. It is unclear, however, what accounts for the exceedingly long latency in this response.


Asunto(s)
Adenosina/toxicidad , Pulmón/inervación , Fibras Nerviosas/fisiología , Respiración/efectos de los fármacos , Adenosina/administración & dosificación , Anestesia , Animales , Capsaicina/farmacología , Células Quimiorreceptoras/efectos de los fármacos , Células Quimiorreceptoras/fisiología , Ventrículos Cardíacos , Inyecciones , Pulmón/efectos de los fármacos , Pulmón/fisiología , Masculino , Ventilación Pulmonar/efectos de los fármacos , Antagonistas de Receptores Purinérgicos P1 , Ratas , Ratas Sprague-Dawley , Receptores Purinérgicos P1/fisiología , Reflejo/fisiología , Respiración/fisiología , Nervio Vago/fisiología , Nervio Vago/ultraestructura , Xantinas/farmacología
15.
J Appl Physiol (1985) ; 68(3): 955-61, 1990 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-1971272

RESUMEN

The acute ventilatory response to inhalation of cigarette smoke was studied in anesthetized Sprague-Dawley rats. Cigarette smoke (6 ml, 50%) generated by a machine was inhaled spontaneously via a tracheal cannula. Within the first two breaths of smoke inhalation, a slowing of respiration resulting from a prolonged expiratory duration (173 +/- 6% of the base line; n = 32) was elicited in 88% of the rats studied. This initial inhibitory effect on breathing was not affected either by an increase (410%) in the nicotine content of the cigarette smoke or by pretreatment with hexamethonium (33 mg/kg iv). However, bilateral vagotomy completely eliminated the initial ventilatory inhibition. Cooling both vagi to 5.1 degrees C blocked the reflex apneic response to lung inflation, but it did not abolish the inhibitory effect of smoke. After the initial response, a rapid shallow breathing pattern developed and reached its peak 5-12 breaths after inhalation of high-nicotine cigarette smoke; this delayed response could not be prevented by vagotomy and was undetectable after inhalation of low-nicotine smoke. We conclude that the initial inhibitory effect of smoke on breathing is mediated by vagal bronchopulmonary C-fiber afferents, which are stimulated by smoke constituents other than nicotine, whereas the delayed tachypneic response to smoke is caused by the absorbed nicotine.


Asunto(s)
Respiración/fisiología , Fumar/fisiopatología , Animales , Apnea/etiología , Apnea/fisiopatología , Células Quimiorreceptoras/efectos de los fármacos , Células Quimiorreceptoras/fisiopatología , Hexametonio , Compuestos de Hexametonio/farmacología , Fibras Nerviosas/fisiología , Nicotina/toxicidad , Ratas , Ratas Endogámicas , Respiración/efectos de los fármacos , Nervio Vago/fisiología
16.
J Appl Physiol (1985) ; 59(1): 229-36, 1985 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-4030566

RESUMEN

To determine whether the acute ventilatory responses to inhaled cigarette smoke are affected by a difference in nicotine level, control cigarettes (low-nicotine research cigarettes) were laced with nicotine to generate an increase of 330% (mean) in nicotine content with little or no change in the levels of other smoke constituents. Acute ventilatory responses to both control and nicotine-laced cigarettes were determined and compared in six awake chronic dogs. Spontaneous inhalation of nicotine-laced cigarette smoke (10% concn, 750 ml vol) via a tracheostomy tube caused distinct and consistent changes in breathing pattern on the first or second breath of inhaled smoke: an apnea in three dogs, an augmented inspiration in two dogs, and rapid shallow breathing in one dog. No significant change in breathing pattern was found immediately following inhalation of control cigarette smoke. Both types of cigarettes caused a delayed hyperpnea. However, the increase in minute ventilation induced by nicotine-laced cigarettes (from a base line of 2.8 to a peak of 25.7 l/min) was significantly greater than that by control cigarettes (from 2.9 to 5.5 l/min). Results of this study suggest that nicotine is responsible for the elicitation of both the immediate and delayed ventilatory responses to inhaled cigarette smoke generated under our experimental conditions.


Asunto(s)
Nicotiana , Nicotina/farmacología , Plantas Tóxicas , Respiración/efectos de los fármacos , Humo/análisis , Animales , Estado de Conciencia , Perros , Nicotina/análisis , Volumen de Ventilación Pulmonar , Factores de Tiempo
17.
J Appl Physiol (1985) ; 63(4): 1366-73, 1987 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-3693170

RESUMEN

The role of vagal bronchopulmonary C-fiber afferents in eliciting the immediate changes in breathing pattern after acute inhalation of cigarette smoke was assessed with a selective blockade of myelinated vagal afferents (innervating both stretch and irritant receptors) utilizing the method of differential cooling. In 15 of 17 chloralose-anesthetized dogs tested, spontaneous inhalation of cigarette smoke (19.7% avg conc, 500-700 ml vol) reproducibly caused the following immediate responses: apnea, bradycardia, and hypotension. These responses occurred within 1 to 2 breaths of smoke inhalation and were followed by a delayed hyperpnea. The apneic duration reached 326 +/- 33% (SE) (n = 15) of the mean base-line expiratory duration. Differential cold block of both vagi (coolant temperature 8.4 +/- 0.3 degrees C) abolished the reflex apnea induced by a positive-pressure (7-10 cmH2O) lung inflation but did not affect the apneic response to smoke inhalation (345 +/- 35%). The smoke-induced apnea was completely abolished by lowering the coolant temperature to -1.3 +/- 0.2 degrees C (n = 10) or by bilateral vagotomy (n = 5) and returned to the control level after both vagi were rewarmed. Based on these results, we suggest that the immediate apneic response to inhaled cigarette smoke is elicited by a stimulation of vagal C-fiber afferents in the lungs and airways.


Asunto(s)
Apnea/etiología , Bronquios/inervación , Pulmón/inervación , Humo/efectos adversos , Vías Aferentes/fisiología , Animales , Presión Sanguínea/efectos de los fármacos , Capsaicina/farmacología , Frío , Perros , Frecuencia Cardíaca/efectos de los fármacos , Nervio Vago/fisiología
18.
J Appl Physiol (1985) ; 60(6): 2123-7, 1986 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-3087942

RESUMEN

The purpose of this study was to develop an isolated upper airway preparation in conscious dogs. Each of the four dogs was trained to wear an individually fitted respiratory mask and surgically prepared with two side-hole tracheostomies. After full recovery, one endotracheal tube was inserted caudally into the lower tracheostomy hole and another tube cranially into the upper tracheostomy. When the two endotracheal tubes were connected to a breathing circuit including a box-balloon system, the magnitude and pattern of the inspiratory flow through the upper airway were identical to that inhaled spontaneously into the lungs by the dogs, but the gas medium inhaled into the upper airway could be independently controlled. Thus it allowed test gas mixtures to be inhaled spontaneously through an isolated upper airway. One limitation was that the inspired gas remained in the upper airway during expiration, but this can be corrected by a simple modification of the breathing circuit. This preparation was tested in studying the respiratory effects of upper airway exposure to CO2 gas mixtures. Our results showed small but significant reduction in both rate and volume of respiration when the concentration of CO2 gas mixture inhaled through the upper airway exceeded 5%. Irregular breathing patterns were frequently elicited in these dogs by higher concentrations (greater than 12%) of CO2.


Asunto(s)
Fisiología/métodos , Fenómenos Fisiológicos Respiratorios , Resistencia de las Vías Respiratorias , Animales , Dióxido de Carbono/farmacología , Estado de Conciencia , Perros , Concentración Osmolar , Fisiología/instrumentación , Ventilación Pulmonar , Respiración/efectos de los fármacos , Espacio Muerto Respiratorio , Sistema Respiratorio/efectos de los fármacos , Volumen de Ventilación Pulmonar , Factores de Tiempo
19.
J Neurosurg ; 93(2): 201-7, 2000 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-10930004

RESUMEN

OBJECT: It is standard practice for the oncological follow-up of patients with brain tumors (especially in the setting of clinical trials) to include neurological examination and neuroradiological studies such as computerized tomography (CT) or magnetic resonance (MR) imaging in addition to evaluation of the patients' symptomatology and performance score. The validity of this practice and its impact on the welfare of patients with high-grade gliomas has not been adequately assessed. The purpose of this study is to provide such an assessment. METHODS: The authors studied 231 similarly treated patients who were participating in three prospective North Central Cancer Treatment Group or Mayo Clinic trials who developed progressive disease during follow up. According to the protocol, the symptom status, performance score, results of neurological examination, and CT or MR status were recorded prospectively in each patient at each evaluation (every 6-8 weeks). At progression, 177 (77%) of 231 patients experienced worsening of their baseline symptoms or they developed new ones. In the remaining 54 asymptomatic patients (23%), neuroradiological imaging revealed the progression. Asymptomatic progression was more likely to be detected on MR imaging compared with CT studies (p < 0.01). In no asymptomatic patient was progression detected on neurological examination alone. The median survival time after tumor recurrence was 13.3 weeks in symptomatic patients compared with 41.7 weeks in the asymptomatic group (p < 0.0001). Asymptomatic patients were more aggressively treated, with surgery (p < 0.0001) and second-line chemotherapy (p < 0.0002). Multivariate analysis of survival time following first progression by using both classification and regression trees and Cox models showed that treatment at recurrence was the most important prognostic variable. CONCLUSIONS: Symptoms are the most frequent indicators of progression in patients with high-grade gliomas (77%). All asymptomatic progressions were detected on neuroradiological studies; MR imaging was more likely than CT scanning to reveal asymptomatic recurrences. Survival after disease progression was significantly longer in asymptomatic patients and could be related both to treatment following progression and to other favorable prognostic factors such as performance score.


Asunto(s)
Neoplasias Encefálicas/diagnóstico , Glioma/diagnóstico , Índice de Severidad de la Enfermedad , Neoplasias Encefálicas/clasificación , Neoplasias Encefálicas/patología , Progresión de la Enfermedad , Femenino , Glioma/clasificación , Glioma/patología , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Recurrencia Local de Neoplasia/diagnóstico , Estadificación de Neoplasias/métodos , Examen Neurológico , Valor Predictivo de las Pruebas , Análisis de Supervivencia , Tomografía Computarizada por Rayos X
20.
Am J Clin Oncol ; 14(2): 152-5, 1991 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-2028922

RESUMEN

Sixty-two patients with biopsy-proven, measurable disseminated malignant melanoma received either the combination IFN-alpha 2A with BCNU (30 patients) or the combination cimetidine with BCNU (32 patients) in parallel noncomparative Phase II trials. From patients receiving IFN-alpha 2A plus BCNU, we observed a 7% response rate: 1 complete response (CR) and 1 partial response (PR) (soft tissue disease with durations of 6.9 and 11.5+ months, respectively). Median time to progression (MTP) was 1.8 months and median survival time (MST) was 3.8 months. Myelosuppression and a flu-type illness were the most common toxicities. From patients receiving cimetidine plus BCNU, the response rate was 16%: 4 PRs (soft tissue disease, 3.8 months; visceral, 2.1, 4.0+, and 9.7 months) and 1 CR (soft tissue, 14.3+ months). MTP and MST were 1.9 and 5.5 months, respectively. Myelosuppression and nausea/vomiting were the most common side effects. Although each of these regimens had great conceptual allure, neither offered any durable impact on the natural history of disseminated malignant melanoma. Nevertheless, alternative combinations of biological response modifiers (BRMs) and BRMs with biochemical modulators or cytotoxic agents may provide some useful alternatives for further clinical investigations.


Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Carmustina/uso terapéutico , Cimetidina/administración & dosificación , Interferón-alfa/uso terapéutico , Melanoma/tratamiento farmacológico , Adulto , Anciano , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Carmustina/administración & dosificación , Carmustina/efectos adversos , Cimetidina/efectos adversos , Evaluación de Medicamentos , Femenino , Humanos , Interferón alfa-2 , Interferón-alfa/efectos adversos , Masculino , Melanoma/terapia , Persona de Mediana Edad , Proteínas Recombinantes , Inducción de Remisión , Tasa de Supervivencia , Factores de Tiempo
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