RESUMEN
BACKGROUND AND PURPOSE: gamma-Secretase inhibitors (GSIs) block NOTCH receptor cleavage and pathway activation and have been under clinical evaluation for the treatment of malignancies such as T-cell acute lymphoblastic leukaemia (T-ALL). The ability of GSIs to decrease T-ALL cell viability in vitro is a slow process requiring >8 days, however, such treatment durations are not well tolerated in vivo. Here we study GSI's effect on tumour and normal cellular processes to optimize dosing regimens for anti-tumour efficacy. EXPERIMENTAL APPROACH: Inhibition of the Notch pathway in mouse intestinal epithelium was used to evaluate the effect of GSIs and guide the design of dosing regimens for xenograft models. Serum Abeta(40) and Notch target gene modulation in tumours were used to evaluate the degree and duration of target inhibition. Pharmacokinetic and pharmacodynamic correlations with biochemical, immunohistochemical and profiling data were used to demonstrate GSI mechanism of action in xenograft tumours. KEY RESULTS: Three days of >70% Notch pathway inhibition was sufficient to provide an anti-tumour effect and was well tolerated. GSI-induced conversion of mouse epithelial cells to a secretory lineage was time- and dose-dependent. Anti-tumour efficacy was associated with cell cycle arrest and apoptosis that was in part due to Notch-dependent regulation of mitochondrial homeostasis. CONCLUSIONS AND IMPLICATIONS: Intermittent but potent inhibition of Notch signalling is sufficient for anti-tumour efficacy in these T-ALL models. These findings provide support for the use of GSI in Notch-dependent malignancies and that clinical benefits may be derived from transient but potent inhibition of Notch.
Asunto(s)
Secretasas de la Proteína Precursora del Amiloide/antagonistas & inhibidores , Antineoplásicos/farmacología , Óxidos S-Cíclicos/farmacología , Leucemia-Linfoma Linfoblástico de Células T Precursoras/tratamiento farmacológico , Receptor Notch1/fisiología , Tiadiazoles/farmacología , Péptidos beta-Amiloides/sangre , Animales , Antineoplásicos/administración & dosificación , Antineoplásicos/efectos adversos , Apoptosis , Diferenciación Celular , Línea Celular Tumoral , Colon/citología , Colon/efectos de los fármacos , Óxidos S-Cíclicos/administración & dosificación , Óxidos S-Cíclicos/efectos adversos , Regulación hacia Abajo , Esquema de Medicación , Humanos , Mucosa Intestinal/citología , Mucosa Intestinal/efectos de los fármacos , Potencial de la Membrana Mitocondrial/efectos de los fármacos , Ratones , Ratones Desnudos , Proteínas Mitocondriales/biosíntesis , Proteínas Mitocondriales/genética , Trasplante de Neoplasias , Fragmentos de Péptidos/sangre , Leucemia-Linfoma Linfoblástico de Células T Precursoras/metabolismo , Leucemia-Linfoma Linfoblástico de Células T Precursoras/patología , Receptor Notch1/genética , Transducción de Señal , Tiadiazoles/administración & dosificación , Tiadiazoles/efectos adversos , Trasplante HeterólogoRESUMEN
In order to assess the confidence of healthcare professionals in diagnosing and managing COPD telephone interviews were conducted with 60 practice nurses and 46 general practitioners (GPs) in 2001 and 61 nurses and 39 GPs in 2005. The nurses all ran respiratory clinics. 80% of GPs were confident about diagnosing COPD and this had increased from 52% in 2001. Fifty five percent of nurses were confident and there was no change from 2001. In 2005, 79% of GPs and 70% of nurses were confident about differentiating asthma and COPD. Smoking history, breathlessness, age of onset, lack of response to asthma therapy and cough were reported as features differentiating COPD from asthma. Most respondents stated that spirometry is essential to diagnose COPD and in 2005 nearly all practices had access to a spirometry service. GPs were more confident about interpreting spirometry results in 2005 than nurses and their confidence had increased significantly from 2001. In 2005, nearly all respondents had heard of pulmonary rehabilitation, and significantly more had a programme in their area in 2005 than 2001 (69% vs. 49% p=0.05). Fifty four percent of GPs were confident about which patients to refer for long term oxygen therapy in 2005 but nurses were less confident. There had not been any significant change between 2001 and 2005. In 2005 only 35% of respondents had access to a pulse oximeter. When presented with case scenarios, GPs self-reported confidence was not reflected in their diagnoses or investigation and management strategies and they seem to favour cardiac over respiratory diagnoses.
Asunto(s)
Competencia Clínica/normas , Medicina Familiar y Comunitaria/normas , Personal de Salud/psicología , Enfermedad Pulmonar Obstructiva Crónica/terapia , Encuestas y Cuestionarios , Asma/diagnóstico , Competencia Clínica/estadística & datos numéricos , Diagnóstico Diferencial , Humanos , Guías de Práctica Clínica como Asunto , Enfermedad Pulmonar Obstructiva Crónica/diagnóstico , Enfermedad Pulmonar Obstructiva Crónica/enfermería , Reino UnidoRESUMEN
Exacerbations of chronic obstructive pulmonary disease (COPD) have serious health consequences for patients and are strongly associated with unscheduled healthcare resource use. This study used a preference-based quality of life measure questionnaire (EQ-5D) to evaluate the impact of exacerbation on health status and utility during a patient's admission to hospital and short-term follow-up. Costs of admission were calculated. In total, 149 patients consented to take part in the study representing 222 admissions to hospital. At admission patients reported high levels of problems for all dimensions of the EQ-5D. Mean utility (-0.077) and Visual Analogue Scale (25.9) values indicated great impairment, with 61% of patients having a negative utility value representing a health state equivalent to 'worse than death' at admission. Many problems were still reported at discharge. By 3 months follow-up patients had deteriorated, with percentages of patients reporting problems in mobility (98%) and usual activity (88%) almost back up to admission levels. Health status and utility values were similar regardless of lung function at admission and at discharge. Approximately half of the patients in each category had a negative utility value at admission representing a health state 'worse than death', with similar levels of improvement by discharge. The mean cost of an admission was 2130.34 pounds (SD 1326.09) with only a mean of 110.37 pounds(5%) because of medication. No differences were noted by lung function category. In conclusion, all COPD patients requiring admission for an exacerbation suffer a serious deterioration in health status which, although improves during admission, notably deteriorates by 3 months postdischarge.
Asunto(s)
Estado de Salud , Evaluación de Resultado en la Atención de Salud , Enfermedad Pulmonar Obstructiva Crónica/fisiopatología , Calidad de Vida , Anciano , Costos y Análisis de Costo , Femenino , Estudios de Seguimiento , Volumen Espiratorio Forzado/fisiología , Hospitalización/economía , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Enfermedad Pulmonar Obstructiva Crónica/economía , Enfermedad Pulmonar Obstructiva Crónica/terapia , Índice de Severidad de la Enfermedad , Encuestas y CuestionariosRESUMEN
Although growth factor receptors are generally thought to carry out their role in signal transduction at the cell surface, many of these transmembrane proteins translocate to the nucleus after ligand stimulation. Here, we show that the nuclear translocation of fibroblast growth factor receptor (FGFR)1 occurs via a mechanism distinct from classical nuclear import but dependent on importin beta, a component of multiple nuclear import pathways. Furthermore, we show that nuclear FGFR1 induces c-Jun and is involved in the regulation of cell proliferation. These data are the first description of a nuclear import pathway for transmembrane growth factor receptors and elucidate a novel signal transduction pathway from the cell surface to the nucleus.
Asunto(s)
Transporte Activo de Núcleo Celular/fisiología , División Celular/fisiología , Proteínas Nucleares/metabolismo , Receptores de Factores de Crecimiento de Fibroblastos/metabolismo , Transducción de Señal/fisiología , Células 3T3 , Transporte Activo de Núcleo Celular/efectos de los fármacos , Adenosina Trifosfato/metabolismo , Animales , Antimetabolitos/farmacología , Ciclo Celular/fisiología , Fraccionamiento Celular , Desoxiglucosa/farmacología , Inhibidores Enzimáticos/farmacología , Immunoblotting , Carioferinas , Ratones , Microscopía Confocal , Oligomicinas/farmacología , Proteínas Proto-Oncogénicas c-jun/metabolismo , Proteínas Recombinantes/metabolismo , TransfecciónRESUMEN
Using the cytoplasmic domain of fibroblast growth factor receptor 1 (FGFR1) as bait in a yeast two-hybrid screen, Grb14 was identified as a FGFR1 binding partner. A kinase-inactive mutant of FGFR1 failed to interact with Grb14, indicating that activation of FGFR1 is necessary for binding. Deletion of the C-tail or mutation of both C-tail tyrosine residues of FGFR1 to phenylalanine abolished binding, and deletion of the juxtamembrane domain of the receptor reduced binding, suggesting that Grb14 binds to FGFR1 at multiple sites. Co-immunoprecipitation and in vitro binding assays demonstrated that binding of Grb14 to FGFR1 in mammalian cells was dependent on receptor activation by fibroblast growth factor-2 (FGF-2). Deletion of the Src homology 2 (SH2) domain of Grb14 reduced but did not block binding to FGFR1 and eliminated dependence on receptor activation. The SH2 domain alone bound both FGFR1 and platelet-derived growth factor receptor, whereas full-length Grb14 bound only FGFR1, suggesting that regions upstream of the SH2 domain confer specificity for FGFR1. Grb14 was phosphorylated on serine and threonine residues in unstimulated cells, and treatment with FGF-2 enhanced this phosphorylation. Expression of exogenous Grb14 inhibited FGF-2-induced cell proliferation, whereas a point-mutated form of Grb14 incapable of binding to FGFR1 enhanced FGF-2-induced mitogenesis. These data demonstrate an interaction between activated FGFR1 and Grb14 and suggest a role for Grb14 in FGF signaling.
Asunto(s)
Proteínas/metabolismo , Proteínas Tirosina Quinasas Receptoras/metabolismo , Receptores de Factores de Crecimiento de Fibroblastos/metabolismo , Proteínas Adaptadoras Transductoras de Señales , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Sitios de Unión , Factores de Crecimiento de Fibroblastos/metabolismo , Ratones , Datos de Secuencia Molecular , Fosforilación , Unión Proteica , Proteínas/genética , Receptor Tipo 1 de Factor de Crecimiento de Fibroblastos , Homología de Secuencia de Aminoácido , Transducción de Señal , Técnicas del Sistema de Dos Híbridos , Dominios Homologos srcRESUMEN
TA20 is a cDNA clone which was previously reported to encode a novel neuronal differentiation factor. However, the majority of this clone has near perfect DNA sequence homology with cytochrome b mitochondrial sequence and an additional 5' region which lacks homology with any previously reported sequence. Furthermore, careful study of the library construction method indicates that the full length TA20 clone is likely an artifact arising from the head-to-head blunt-ended ligation of two unrelated cDNAs. Thus, the effects on growth and neurite outgrowth observed in correlation with the overexpression of TA20 in neuronal cells, as well as its mRNA distribution in the developing rat brain require further study.
Asunto(s)
Grupo Citocromo b/fisiología , Neuronas/fisiología , Factores de Transcripción/fisiología , Regiones no Traducidas 5'/genética , Regiones no Traducidas 5'/fisiología , Animales , Secuencia de Bases , Diferenciación Celular/fisiología , Grupo Citocromo b/genética , Ratones , Datos de Secuencia Molecular , Neuritas/fisiología , Neuronas/enzimología , Biosíntesis de Proteínas , ARN Mensajero/biosíntesis , Ratas , Sistemas de Lectura , Factores de Transcripción/genéticaRESUMEN
Astrocytes play a critical role in the development of the CNS and its response to injury and disease. A key indicator of astrocyte activation is the increased accumulation of intermediate filaments composed of glial fibrillary acidic protein (GFAP). Treatment of astrocytes in vitro with transforming growth factor-beta1 (TGF-beta1) produced little morphological change, but resulted in a significant increase in GFAP mRNA and protein. Treatment with basic fibroblast growth factor (FGF-2) produced a dramatic change from a polygonal to a stellate morphology, and resulted in a significant decrease in GFAP mRNA and protein. FGF-2 also inhibited the TGF-beta1-mediated increase in GFAP mRNA and protein. Cycloheximide did not block the effects of TGF-beta1 or FGF-2 on GFAP mRNA levels, but blocked the inhibitory effects of FGF-2 on the TGF-beta1-mediated increase in GFAP expression. All effects of FGF-2 were blocked by co-incubation with 5'-methylthioadenosine, a specific inhibitor of FGF-2-induced tyrosine kinase activity and FGF receptor (FGFR) autophosphorylation. We also examined astrocyte expression of FGFR, and demonstrate the presence of FGFR 1 and 2, and lower levels of FGFR 3. Our results demonstrate that TGF-beta1 and FGF-2 cause differential effects on the astrocyte cytoskeleton and morphology, suggesting an uncoupling of process outgrowth from GFAP synthesis.
Asunto(s)
Astrocitos/metabolismo , Factor 2 de Crecimiento de Fibroblastos/farmacología , Proteína Ácida Fibrilar de la Glía/biosíntesis , Factor de Crecimiento Transformador beta/farmacología , Animales , Astrocitos/efectos de los fármacos , Northern Blotting , Western Blotting , Células Cultivadas , Reactivos de Enlaces Cruzados , Cicloheximida/farmacología , Desoxiadenosinas/farmacología , Inmunohistoquímica , Radioisótopos de Yodo , Pruebas de Precipitina , Inhibidores de la Síntesis de la Proteína/farmacología , ARN Mensajero/biosíntesis , ARN Mensajero/aislamiento & purificación , Ratas , Ratas Sprague-Dawley , Tionucleósidos/farmacologíaRESUMEN
BACKGROUND: In 1923 the French surgeon Henri Hartmann described an operation for rectosigmoid cancer as an alternative to abdomino-perineal resection for high-risk patients. In the subsequent years, the indications for performing the Hartmann procedure have broadened to include complicated diverticulitis, ischemic bowel, iatrogenic perforations, volvulus, and colitis. METHODS: We have retrospectively reviewed our experience in 185 patients who underwent the Hartmann procedure from January 1981 to December 1995. Charts were reviewed for indications, morbidity, and mortality and to determine the outcome of patients who underwent the Hartmann procedure. RESULTS: The main indications for performing the Hartmann procedure were complicated diverticulitis (including perforation, obstruction, and abscesses) in 108 patients, rectosigmoid cancer in 31 patients, and other indications in 46 patients. There were a total of 27 deaths for an in-hospital mortality of 14%. All complications occurred at a rate of less than 9%. Of the 158 surviving patients, 90 (57%) eventually underwent the second stage of the operation to restore bowel continuity. The average length of time between initial resection and reanastomosis was 149 days. There were no deaths associated with the second stage of the procedure and complications occurred at a rate less than 4%. CONCLUSIONS: This is the largest reviewed series of the Hartmann procedure. Mortality is lower than in other reported series, and morbidity is low. Our data demonstrate that the second stage of the procedure, in properly selected individuals, is a procedure that can be performed with minimal morbidity and no mortality. This is different from other published reports. We conclude that the Hartmann procedure is a safe and efficacious option for the surgeon confronted with the complex pathology of the rectosigmoid area, with acceptable morbidity and mortality.
Asunto(s)
Diverticulitis/cirugía , Enfermedades Intestinales/cirugía , Neoplasias del Recto/cirugía , Neoplasias del Colon Sigmoide/cirugía , Anciano , Humanos , Complicaciones Posoperatorias , Estudios Retrospectivos , Resultado del TratamientoRESUMEN
The efficacy and tolerability of fluticasone propionate (FP) 2 mg daily via a metered-dose inhaler and Volumatic (Glaxo Wellcome) spacer device was compared with nebulized budesonide (nBUD), 2 and 4 mg daily, in a multi-centre, open-label, cross-over study of adult asthmatics. Patients received, in random order, either 4 weeks of treatment with FP followed by 4 weeks of treatment with nBUD, or vice versa, with an intervening 4 week 'wash-out' period between treatments. Thirty patients completed the study, of whom 24 were evaluable. In terms of the primary efficacy parameter, change in mean morning peak expiratory flow (PEF) (l min-1) from baseline to the fourth week of each treatment period, FP was more effective than nBUD [mean difference (FP-nBUD) 21.1 l min-1, P = 0.007, 95% CI (6.5, 35.7)]. Sub-group analysis demonstrated FP to be superior to the 4 mg nBUD [mean treatment difference (FP-nBUD) 42.9 l min-1, P = 0.026, 95% CI (7.1, 78.8)] and at least as efficacious as the 2 mg nBUD sub-group [mean treatment difference (FP-nBUD) 10.2 l min-1, P = 0.211, 95% CI (-6.5, 26.9)]. Furthermore, larger reductions in diurnal variation were observed during FP treatment [mean treatment difference (FP-nBUD) -4.4 percentage points, P = 0.028, 95% CI (-8.4, -0.5)]. There was no significant difference between the treatments for the proportion of symptom-free 24 h periods. Of those expressing a preference, significantly more patients found FP via a metered-dose inhaler and spacer device both easier to administer (78%, P = 0.007) and more convenient to take (76%, P = 0.008) than nebulized budesonide. In addition, cost per patient analysis showed that nebulized budesonide was from 1.7 to 3.5 times more expensive than FP.
Asunto(s)
Androstadienos/administración & dosificación , Antiinflamatorios/administración & dosificación , Asma/tratamiento farmacológico , Budesonida/administración & dosificación , Adolescente , Adulto , Anciano , Androstadienos/economía , Androstadienos/uso terapéutico , Antiinflamatorios/economía , Antiinflamatorios/uso terapéutico , Budesonida/economía , Budesonida/uso terapéutico , Costos y Análisis de Costo , Estudios Cruzados , Sistemas de Liberación de Medicamentos , Fluticasona , Humanos , Persona de Mediana Edad , Nebulizadores y Vaporizadores , Satisfacción del Paciente , Ápice del Flujo Espiratorio/efectos de los fármacosRESUMEN
Our previous studies have shown that injection of basic fibroblast growth factor (bFGF) into a brain wound enhances astrocyte hypertrophy and macrophage-microglia proliferation in areas adjacent to the lesion. In the present study, designed to test the effects of co-administration of bFGF and heparan sulfate (HS), rats received injections of 200 ng bFGF, 200 ng bFGF with 50 microg HS, or 50 microg HS into a brain wound. Glial proliferation and astrocyte hypertrophy were evaluated in seven non-overlapping subfields in the mid-cortex including the wound edge. Our results show that bFGF-HS, compared to bFGF or HS alone, enhanced the total area of GFAP staining in all subfields except the one nearest to the wound edge. The combination of bFGF and HS did not increase total glial or astrocyte proliferation. We propose that the observed effects resulted from a greater diffusion of bFGF-HS complex into the brain parenchyma, where it bypassed low-affinity binding sites that would otherwise sequester free bFGF. Our results suggest that bFGF-HS complex, compared to bFGF alone, may gain entry into the brain more readily, reach higher concentrations and be more effective as a neurotrophic agent.
Asunto(s)
Interacciones Farmacológicas , Factor 2 de Crecimiento de Fibroblastos/farmacología , Heparitina Sulfato/farmacología , Neuroglía/efectos de los fármacos , Animales , Inmunohistoquímica , Masculino , Ratas , Ratas Sprague-DawleyRESUMEN
Traumatic injuries to the central nervous system result in astrogliosis and the formation of a dense scar at the site of the wound. Basic fibroblast growth factor (bFGF) has mitogenic and morphogenic effects on astrocytes, and an interaction between bFGF and its receptor is likely to play a role in astrogliosis. We examined trauma-induced changes in the spatial and temporal expression of FGF receptor (FGFR) in adult rats over a 28-day period following a stereotaxic lesion through the cortex and hippocampus. Immunohistochemistry and image analysis were used to evaluate the changes. Antibody characterization studies strongly suggested that staining represented FGFR 1, but did not rule out possible cross-reactivity with FGFR 2 or 3. Double immunohistochemistry for FGFR and glial fibrillary acidic protein demonstrated that mature astrocytes expressed FGFR. Expression was increased on astrocytes adjacent to the wound cavity by Day 2 postlesion. Staining increased further through Day 10 and decreased to control values by Day 28, except for a sustained increase in staining of reactive astrocytes immediately adjacent to the wound cavity. Basic FGF was detected in the nuclei of cells staining for FGFR, suggesting that FGFR-expressing astrocytes also contained bFGF. These data demonstrate a time course for astrocyte expression of FGFR that precedes and parallels the time course for astrocyte hypertrophy. Our observations suggest that endogenous bFGF, acting directly on FGFR-expressing astrocytes, may contribute to astrogliosis.
Asunto(s)
Lesiones Encefálicas/metabolismo , Receptores de Factores de Crecimiento de Fibroblastos/biosíntesis , Animales , Anticuerpos Monoclonales , Especificidad de Anticuerpos , Modelos Animales de Enfermedad , Factor 2 de Crecimiento de Fibroblastos/análisis , Técnica del Anticuerpo Fluorescente , Técnicas para Inmunoenzimas , Inmunohistoquímica , Masculino , Ratas , Ratas Sprague-Dawley , Receptores de Factores de Crecimiento de Fibroblastos/inmunología , Receptores de Factores de Crecimiento de Fibroblastos/metabolismo , Factores de TiempoRESUMEN
Bambuterol was compared with placebo in 28 patients with nocturnal asthma in a randomized, double-blind cross-over study. All patients were symptomatic despite taking inhaled beta 2-agonists, inhaled corticosteroids (in 26 patients the median daily dose was 1500 micrograms) and oral corticosteroids (in eight patients the median daily dose was 10 mg). Patients demonstrated > or = 20% overnight fall in peak expiratory flow (PEF) for at least half of the 14-day run-in period. They then entered two treatment periods lasting 14 days when bambuterol 20 mg nocte and placebo were given in random order. Compared to placebo, bambuterol produced a 16% improvement in mean PEF on waking (271 l min-1 vs. 239 l min-1 P = 0.0002) and a 10% improvement in evening PEF measured 24 h after drug intake (318 l min-1 vs. 296 l min-1 P = 0.01). Bambuterol significantly reduced frequency of nocturnal awakening from 1.1 to 0.7 per night (P = 0.01) and nocturnal beta 2-agonist use from 2.7 to 2.1 puffs (P = 0.0004). Other nocturnal symptoms: cough, wheeze and dyspnoea were also significantly reduced during bambuterol treatment and patients quality of sleep was improved. The results indicate bambuterol (20 mg nocte) provides effective nocturnal bronchodilation with sustained effect for 24 h and may have a useful therapeutic role in the control of symptomatic nocturnal asthma.
Asunto(s)
Asma/tratamiento farmacológico , Broncodilatadores/uso terapéutico , Terbutalina/análogos & derivados , Adulto , Broncodilatadores/efectos adversos , Ritmo Circadiano , Método Doble Ciego , Femenino , Humanos , Masculino , Persona de Mediana Edad , Sueño/efectos de los fármacos , Terbutalina/efectos adversos , Terbutalina/uso terapéuticoRESUMEN
A 25-year-old man presented to the emergency department with an acute onset of frontal sinus pain during descent on a commercial airliner. There was no history of recent upper respiratory infection, sinus infection, or chronic allergic rhinitis. Sinus radiographs demonstrated a left frontal sinus submucosal hematoma. Symptoms improved within 24 hours with systemic and topical decongestants/vasoconstrictors and a nonsteroidal antiinflammatory agent. He was asymptomatic at 1 week postinjury.
Asunto(s)
Aeronaves , Barotrauma/etiología , Sinusitis Frontal/etiología , Adulto , Barotrauma/diagnóstico por imagen , Sinusitis Frontal/diagnóstico por imagen , Sinusitis Frontal/tratamiento farmacológico , Humanos , Masculino , Descongestionantes Nasales/uso terapéutico , RadiografíaRESUMEN
A large (540 square meters) bed of Bathymodiolus n. sp. (Mytilidae: Bivalvia) rings a pool of hypersaline (121.35 practical salinity units) brine at a water depth of 650 meters on the continental slope south of Louisiana. The anoxic brine (dissolved oxygen
RESUMEN
Enprofylline, a recently developed xanthine derivative, is a more potent bronchodilator than theophylline. This study compares the efficacy and safety of enprofylline with theophylline for chronic obstructive airways disease (COAD) in elderly subjects. The study was of a randomized double-blind parallel design and commenced with a 1-week reference period when oral bronchodilators were withdrawn. Patients were then treated with either enprofylline or theophylline 150 mg bd for 2 weeks (period 1) followed by 300 mg bd for a further 3 weeks (period 2). Patients recorded peak expiratory flow rate (PEFR) and adverse experiences, if any, in a diary, daily. Of 111 patients recruited for the study, 85 entered active treatment (theophylline, n = 44; enprofylline, n = 41). Mean age was 72 years and mean bronchodilator reversibility was 22%. Enprofylline increased mean morning PEFR by 11% (period 1) and 19% (period 2) whereas theophylline increased PEFR by 13% and 19%, respectively. From the enprofylline group 29% were withdrawn from the study due mainly to headache and nausea/vomiting and from the theophylline group 7% were withdrawn due mainly to nausea/vomiting. Mean plasma concentrations of enprofylline were 2.0 mg l-1 and 3.4 mg l-1, and with theophylline 5.4 mg l-1 and 10.0 mg l-1 at the end of periods 1 and 2, respectively. Enprofylline and theophylline produced similar improvements in lung functions and symptoms of chronic obstructive airways disease, but enprofylline was less well tolerated than theophylline.