Assuntos
Fármacos Dermatológicos/uso terapêutico , Isotretinoína/uso terapêutico , Anormalidades Induzidas por Medicamentos/etiologia , Acne Vulgar/tratamento farmacológico , Fármacos Dermatológicos/efeitos adversos , Feminino , Humanos , Isotretinoína/efeitos adversos , Masculino , Transtornos do Humor/induzido quimicamente , Guias de Prática Clínica como Assunto , Gravidez , Reino UnidoRESUMO
After discrimination training on a multiple variable-interval extinction schedule of food reinforcement, pigeons were placed on the uncued or mixed version of the same schedule and allowed to make an optional "observing response" that converted the uncued schedule to the corresponding cued schedule by providing a 20-sec exposure to the appropriate discriminative stimulus. The schedule consisted of one hundred 40-sec components, and the probability that any one of them would be a variable-interval component was systematically varied between 0.00 and 1.00. The results showed that the amount of observing behavior was an inverted "U" function of the probability of the variable-interval component. Few observing responses occurred at probabilities of 0.00 or 1.00, and maximum responding occurred at a value less than 0.50.
RESUMO
Twenty to seventy per cent of the reinforcements scheduled for pigeons' fixed-ratio 80 performances were replaced by a 4-sec timeout. Pauses after reinforced ratios were unchanged at 80% reinforcement, but were lengthened at lower reinforcement percentages. Pauses after nonreinforced ratios were shorter than post-reinforcement pauses. When 50% of the reinforcements arranged by a variable-interval 60-sec schedule were replaced by a 4-sec timeout, pauses after reinforcement omission increased. Both frustrative nonreward and reinforcement aftereffects notions can explain the fixed-ratio results; neither easily explains the variable-interval data.
RESUMO
Atopic dermatitis, allergic rhinitis and asthma are a common group of diseases with a familial predisposition. At present there is no suitable predictive or diagnostic marker. Adults with atopic dermatitis or allergic respiratory disease have elevated mononuclear leukocyte cAMP-phosphodiesterase activity. This activity correlates closely with histamine release from basophils. We investigated newborn leukocyte phosphodiesterase activity and histamine release in umbilical cord blood. Phosphodiesterase activity was significantly elevated in cord blood leukocytes of 81 children with a positive history of atopy in first degree relatives, compared to 33 children with a negative history (p less than 0.025). In contrast to adults there was no correlation between phosphodiesterase activity and histamine release. Our studies suggest that elevated phosphodiesterase activity is a primary, genetically linked defect. Fetal basophils would appear to possess cytophilic IgE since they are capable of immunologically stimulated histamine release even without passive, in vitro IgE sensitization. In addition, there are functional differences between adult and cord blood basophils. Longitudinal studies may determine if elevated phosphodiesterase is predictive of atopic states.
Assuntos
3',5'-AMP Cíclico Fosfodiesterases/sangue , Sangue Fetal/enzimologia , Liberação de Histamina , Leucócitos/enzimologia , Adulto , Fatores Etários , Basófilos/análise , Feminino , Sangue Fetal/imunologia , Histamina/sangue , Humanos , Hipersensibilidade/genética , Recém-Nascido , Leucócitos/imunologia , Masculino , Gravidez , PrognósticoRESUMO
The functional relationship between heart rate, under atrial pacing, and the intensity of pacing pulses, was determined for intensities ranging from well below the complete heart rate capture threshold to suprathreshold intensities. A separate capture-intensity function was determined for each of the pacing frequencies 180, 240, 300 and 360 pulses per min, and then used to evaluate the effects of propranolol hydrochloride and atropine sulfate on atrial pacing. Propranolol resulted in an increase in the amount of current (mA) required to achieve a given degree of cardiac capture, whereas atropine resulted in a decrease. These shifts in the capture-intensity functions along the intensity axis were possibly caused by drug antagonism of beta-adrenergic and cholinergic receptors, respectively, although the effects might also have been due to modifications of the electrical responsivity of the cardiac muscle, independently of the neural blockade.
Assuntos
Atropina/farmacologia , Frequência Cardíaca , Marca-Passo Artificial/métodos , Propranolol/farmacologia , Animais , Função Atrial , Relação Dose-Resposta a Droga , Haplorrinos , Frequência Cardíaca/efeitos dos fármacos , Macaca mulattaRESUMO
We describe two patients who developed anaphylaxis type reactions following the application of the topical antibiotic Polyfax (polymixin B and bacitracin). We draw attention to this potentially serious complication of topical antibiotic preparations and emphasize the need for careful history taking before prescribing such preparations.
Assuntos
Anafilaxia/induzido quimicamente , Bacitracina/efeitos adversos , Polimixina B/efeitos adversos , Idoso , Idoso de 80 Anos ou mais , Bacitracina/administração & dosagem , Quimioterapia Combinada/efeitos adversos , Feminino , Humanos , Polimixina B/administração & dosagem , Úlcera Varicosa/tratamento farmacológicoRESUMO
A 56-year-old man with long-standing chronic plaque psoriasis was noted to be acromegalic. Investigations confirmed the presence of a large pituitary adenoma and following treatment of this by hypophysectomy his psoriasis cleared dramatically within 3 weeks.
Assuntos
Acromegalia/complicações , Psoríase/etiologia , Adenoma/complicações , Adenoma/cirurgia , Humanos , Hipofisectomia , Masculino , Pessoa de Meia-Idade , Neoplasias Hipofisárias/complicações , Neoplasias Hipofisárias/cirurgia , Psoríase/terapiaRESUMO
This experiment extends Pavlov's method of contrasts for training a stimulus discrimination to the case of the cardiac conditional response in the rhesus monkey. It explores the parameter of temporal placement of an additional stimulus ("CS2") within a 10-sec CS (or "CS1"), with the appearance of the former stimulus on any trial signalling the absence of UCS (electric shock) on that trial. This experimental paradigm is a parallel to that of the "intruded stimulus" studies in operant conditioning. In both cases, several ways of describing the function of the added stimulus are possible, but all seem reducible to the same operational terms. Data were taken in the present study with respect to the form and latency of the cardiac rate changes produced by intrusion of CS2 (light), across a range of placements varying from simultaneity with CS1 (a different light) onset to two sec before UCS would have been delivered. The control of CS2 over the cardiac rate CR was occasionally exhibited with a latency as short as three beats after stimulus onset. The order of CS2 temporal placements to which a subject was exposed was a factor in determining the form of the conditioned cardiac rate response to CS1.
Assuntos
Condicionamento Clássico/fisiologia , Frequência Cardíaca , Esquema de Reforço , Animais , Aprendizagem por Discriminação/fisiologia , Macaca mulatta , Masculino , Tempo de Reação/fisiologia , Fatores de TempoRESUMO
Erythrokeratoderma variabilis is a rare genodermatosis conventionally regarded as autosomal dominant in inheritance. We describe the clinical features and light and electron microscopic findings in two affected siblings born to unaffected parents and suggest an autosomal recessive mode of inheritance in this family. We also briefly review the literature on this disorder.
Assuntos
Eritema/complicações , Eritema/genética , Genes Recessivos , Ceratose/complicações , Ceratose/genética , Eritema/patologia , Humanos , Lactente , Ceratose/patologia , Masculino , Pele/patologiaRESUMO
Intravenous administration of morphine sulfate often produces urticarial and hypotensive reactions associated with elevations in plasma histamine. The source of this histamine and mechanisms controlling its release are poorly understood. Previous studies of morphine-induced histamine release compared human leukocytes to rat peritoneal mast cells. The effects of morphine on human cutaneous mast cells has not been examined. We studied in vitro histamine release from human basophils and human skin preparations containing cutaneous mast cells to evaluate their relative contribution to the pharmacologic effects of morphine. Human skin mast cell preparations showed dose-dependent histamine release over a morphine concentration range of 1.5 X 10(-5) to 4.5 X 10(-3) M, with peak release occurring at 5 X 10(-4) M, with peak release occurring at 5 X 10(-4) M. Clinically, morphine sulfate is usually injected as a 1.5 X 10(-2) M solution. Histamine release was calcium dependent and equivalent to that obtained with 3 and 10 mM strontium. Morphologic examination revealed degranulation and exocytosis occurring in morphine-stimulated tissue but not in specimens exposed to buffer alone. Lactate dehydrogenase levels did not increase following morphine incubation, thus supporting a noncytolytic mechanism of histamine release. Basophils, in contrast, showed no significant histamine release from exposure to morphine up to 10(-2) M. Concanavalin A, as a positive control in these same preparations, produced a mean histamine release of 21.0%.(ABSTRACT TRUNCATED AT 250 WORDS)
Assuntos
Basófilos/fisiologia , Liberação de Histamina/efeitos dos fármacos , Mastócitos/fisiologia , Morfina/farmacologia , Basófilos/efeitos dos fármacos , Cálcio/farmacologia , Feminino , Sangue Fetal , Humanos , Técnicas In Vitro , Recém-Nascido , L-Lactato Desidrogenase/metabolismo , Leucócitos/citologia , Leucócitos/fisiologia , Masculino , Mastócitos/efeitos dos fármacos , Gravidez , Pele/efeitos dos fármacos , Fenômenos Fisiológicos da Pele , Estrôncio/farmacologiaRESUMO
A 29 year-old female patient suffered vascular collapse which became apparent immediately after general anaesthesia. Resuscitation was prolonged and difficult, and complicated by the need for reoperation. Based on the time history, fentanyl was suspected as the causative agent. Fentanyl allergy was confirmed by skin testing one month later. The case is discussed, and the possible reasons for the delay in appearance of symptoms and signs are considered.
Assuntos
Analgésicos/efeitos adversos , Anafilaxia/induzido quimicamente , Fentanila/efeitos adversos , Testes Intradérmicos , Testes Cutâneos , Adulto , Anestesia Geral , Feminino , Humanos , Risco , Tolmetino/efeitos adversos , Tolmetino/análogos & derivadosRESUMO
BACKGROUND: Antigliadin antibodies (AGA) have been reported in patients with psoriasis. OBJECTIVES: To determine if AGA and other coeliac disease (CD)-associated antibodies correlate with clinical features and activity in patients with psoriasis. METHODS: Patients with psoriasis (n = 130) were investigated for serum IgG and IgA AGA, IgA antitransglutaminase antibody and IgA antiendomysial antibody. Disease characteristics and associated bowel and joint symptoms were determined. All patients were invited to undertake endoscopy with duodenal biopsy. RESULTS: A significantly higher proportion of patients with elevated CD-associated antibody levels was currently on or had previously required systemic immunosuppressants (methotrexate, ciclosporin or etretinate; P = 0.04) or psoralen plus ultraviolet A phototherapy (P = 0.03). One case of CD was diagnosed. CONCLUSIONS: The presence of CD-associated antibodies in psoriasis patients correlates with greater disease activity.