Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 110
Filtrar
1.
Am J Med ; 111(1): 54-63, 2001 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-11448661

RESUMEN

BACKGROUND: Although antidepressants are often used for preventing chronic headache, their effectiveness is uncertain. METHODS: We performed a meta-analysis of English-language, randomized placebo-controlled trials of antidepressants as prophylaxis for chronic headache. RESULTS: Thirty-eight trials were included. Because some compared more than one drug with placebo, 44 study arms were combined using a random effects model. Twenty-five studies focused on migraines, 12 on tension headaches, and 1 on both. Nineteen used tricyclic antidepressants, 18 serotonin antagonists, and 7 selective serotonin reuptake inhibitors. Patients receiving antidepressants were twice as likely to report headache improvement (rate ratio [RR]: 2.0; 95% confidence interval [CI]: 1.6 to 2.4). Because 31% (95% CI: 23% to 40%) more treated patients improved than those receiving placebo, clinicians would need to treat 3.2 patients for 1 patient to improve. The average amount of improvement (standardized mean difference) was 0.94 (95% CI: 0.65 to 1.2), an effect considered large. Treated patients also consumed less analgesic medication (standardized mean difference, -0.7; 95% CI: -0.5 to -0.94). There were no differences in outcomes among the three classes of agents studied or by the type of headache (migraine vs. tension), quality score, length of treatment, or percentage of patients lost to follow-up. Assessment of depression across studies was insufficient to determine if the effects were independent of depression. CONCLUSION: Antidepressants are effective in preventing chronic headaches. Whether this is independent of depression and whether there are differences in efficacy by class of agent needs further study.


Asunto(s)
Antidepresivos/uso terapéutico , Cefalea/prevención & control , Antidepresivos Tricíclicos/uso terapéutico , Enfermedad Crónica , Cefalea/tratamiento farmacológico , Humanos , Evaluación de Resultado en la Atención de Salud , Ensayos Clínicos Controlados Aleatorios como Asunto , Antagonistas de la Serotonina/uso terapéutico , Inhibidores Selectivos de la Recaptación de Serotonina/uso terapéutico , Resultado del Tratamiento
2.
Am J Med ; 108(1): 65-72, 2000 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-11059442

RESUMEN

BACKGROUND: Functional gastrointestinal disorders are common, accounting for up to 50% of gastroenterology referrals, and several randomized controlled trials have evaluated antidepressant therapy for their treatment. METHODS: We performed a meta-analysis of published, English-language, randomized clinical trials on the use of antidepressants for the treatment of patients with functional gastrointestinal disorders. RESULTS: Twelve randomized placebo-controlled trials of antidepressant treatment of functional gastrointestinal disorders were identified. One was excluded for using a combination of a tricyclic and neuroleptic agent. The medications included tricyclic antidepressants (amitriptyline [n = 3], clomipramine [n = 1], desipramine [n = 2], doxepin [n = 1], and trimipramine [n = 2]), and the antiserotonin agent, mianserin (n = 2). In addition, one trial compared two different antidepressants (mianserin and clomipramine) with placebo. Data were abstracted for the dichotomous outcome of symptom improvement in seven studies, and for the continuous variable of pain score in eight studies. The summary odds ratio for improvement with antidepressant therapy was 4.2 (95% confidence interval [CI]: 2.3 to 7.9), and the average standardized mean improvement in pain was equal to 0.9 SD units (95% CI: 0.6 to 1.2 SD units). On average 3.2 patients needed to be treated (95% CI: 2.1 to 6.5 patients) to improve 1 patient's symptom. CONCLUSION: Treatment of functional gastrointestinal disorders with antidepressants appears to be effective. Whether this improvement is independent of an effect of treatment on depression needs further evaluation.


Asunto(s)
Antidepresivos/uso terapéutico , Enfermedades Funcionales del Colon/tratamiento farmacológico , Motilidad Gastrointestinal/efectos de los fármacos , Adulto , Anciano , Antidepresivos/efectos adversos , Estreñimiento/tratamiento farmacológico , Depresión/tratamiento farmacológico , Diarrea/tratamiento farmacológico , Dispepsia/tratamiento farmacológico , Femenino , Humanos , Masculino , Persona de Mediana Edad , Ensayos Clínicos Controlados Aleatorios como Asunto , Proyectos de Investigación , Resultado del Tratamiento
3.
J Gen Intern Med ; 15(9): 659-66, 2000 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-11029681

RESUMEN

BACKGROUND: Fibromyalgia is a common, poorly understood musculoskeletal pain syndrome with limited therapeutic options. OBJECTIVE: To systematically review the efficacy of antidepressants in the treatment of fibromyalgia and examine whether this effect was independent of depression. DESIGN: Meta-analysis of English-language, randomized, placebo-controlled trials. Studies were obtained from searching MEDLINE, EMBASE, and PSYCLIT (1966-1999), the Cochrane Library, unpublished literature, and bibliographies. We performed independent duplicate review of each study for both inclusion and data extraction. MAIN RESULTS: Sixteen randomized, placebo-controlled trials were identified, of which 13 were appropriate for data extraction. There were 3 classes of antidepressants evaluated: tricyclics (9 trials), selective serotonin reuptake inhibitors (3 trials), and S-adenosylmethionine (2 trials). Overall, the quality of the studies was good (mean score 5.6, scale 0-8). The odds ratio for improvement with therapy was 4.2 (95% confidence interval [95% CI], 2.6 to 6.8). The pooled risk difference for these studies was 0.25 (95% CI, 0.16 to 0.34), which calculates to 4 (95% CI, 2.9 to 6.3) individuals needing treatment for 1 patient to experience symptom improvement. When the effect on individual symptoms was combined, antidepressants improved sleep, fatigue, pain, and well-being, but not trigger points. In the 5 studies where there was adequate assessment for an effect independent of depression, only 1 study found a correlation between symptom improvement and depression scores. Outcomes were not affected by class of agent or quality score using meta-regression. CONCLUSION: Antidepressants are efficacious in treating many of the symptoms of fibromyalgia. Patients were more than 4 times as likely to report overall improvement, and reported moderate reductions in individual symptoms, particularly pain. Whether this effect is independent of depression needs further study.


Asunto(s)
Antidepresivos/uso terapéutico , Fibromialgia/tratamiento farmacológico , Adulto , Anciano , Depresión/complicaciones , Femenino , Fibromialgia/clasificación , Fibromialgia/psicología , Humanos , Masculino , Persona de Mediana Edad , Ensayos Clínicos Controlados Aleatorios como Asunto , Índice de Severidad de la Enfermedad , Resultado del Tratamiento
4.
J Fam Pract ; 48(12): 980-90, 1999 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-10628579

RESUMEN

OBJECTIVE: To determine the efficacy of antidepressant therapy for unexplained symptoms or symptom syndromes. SEARCH STRATEGIES: We identified original studies through searching MEDLINE, EMBASE, PsycLIT, the Federal Research in Progress database, and The Cochrane Library. We also searched the bibliographies of primary and review articles for additional studies. SELECTION CRITERIA: We excluded trials of patients with neuropathic, oncologic, or degenerative joint pain. Independent duplicate review of 392 articles identified 94 relevant reports of randomized trials involving 6595 patients across 6 symptom syndromes. Independent duplicate assessment was made for inclusion and data abstraction. Meta-analysis was performed on extractable placebo-controlled data. MAIN RESULTS: Of 94 included trials, most studied either tricyclic antidepressants, antiserotonin antidepressants, selective serotonin reuptake inhibitors (SSRIs), or multiple agents for the treatment of the following syndromes: headache (50), fibromyalgia (18), functional gastrointestinal syndromes (13), idiopathic pain (11), tinnitus (2), and chronic fatigue (2). The quality of the studies was fair (mean score = 4.8 on a scale of 0 to 8). A majority of the studies (69%) demonstrated benefit for at least one outcome measure. Symptom improvement typically did not correlate with depression response in the few studies where it was assessed. Meta-analysis of all extractable data showed a substantial benefit from antidepressants: For the dichotomous outcome of improvement, the odds ratio was 3.4 (95% confidence interval [CI], 2.6 - 4.5), and for continuous outcomes, the standardized mean difference was 0.87 (95% CI, 0.59-1.14). The absolute percentage difference in improvement between the antidepressant and placebo arms was 32%, yielding a number needed to treat of 3 to improve one person's symptoms. Meta-regression indicated no differential effect across the classes of antidepressants; however, onbivariate tally tricyclic studies were associated with a greater likelihood of efficacy than SSRI studies (P = .02). CONCLUSIONS: Antidepressants can be effective for various physical symptoms and symptom syndromes. The relation of outcome to depression and the efficacy of SSRIs needs further study.


Asunto(s)
Antidepresivos/uso terapéutico , Enfermedades Funcionales del Colon/tratamiento farmacológico , Fibromialgia/tratamiento farmacológico , Cefalea/tratamiento farmacológico , Dolor/tratamiento farmacológico , Adulto , Antidepresivos Tricíclicos/uso terapéutico , Enfermedad Crónica , Depresión/tratamiento farmacológico , Medicina Basada en la Evidencia , Femenino , Humanos , Masculino , Ensayos Clínicos Controlados Aleatorios como Asunto/normas , Serotoninérgicos/uso terapéutico , Síndrome
5.
Telemed J ; 2(3): 211-24, 1996.
Artículo en Inglés | MEDLINE | ID: mdl-10165544

RESUMEN

OBJECTIVE: For the last several years the U.S. Department of Defense (DoD) has operated a telemedicine test bed at the U.S. Army Medical Research and Material Command's Medical Advanced Technology Management Office. The goal of this test bed is to reengineer the military health service system from the most forward deployed forces to tertiary care teaching medical centers within the United States by exploiting emerging telemedicine technologies. METHODS: The test bed has conducted numerous proof-of-concept telemedicine demonstrations as part of military exercises and in support of real-world troop deployments. The most ambitious of those demonstrations is Primetime III, an ongoing effort to provide telemedicine and other advanced technology support to medical units supporting Operation Joint Endeavor in Bosnia. RESULTS: Several of the first instances of the clinical use of the Primetime III systems are presented as case reports in this paper. These reports demonstrate capabilities and limitations of telemedicine. CONCLUSION: The Primetime III system demonstrates the technical ability to provide current telecommunications capabilities to medical units stationed in the remote, austere, difficult-to-serve environment of Bosnia. Telemedicine capabilities cannot be used without adequate training, operations, and sustainment support. Video consultations have eliminated the need for some evacuations. The system has successfully augmented the clinical capability of physicians assigned to these medical units. Fullest clinical utilization of telemedicine technologies requires adjustment of conventional clinical practice patterns.


Asunto(s)
Medicina Militar/métodos , Telemedicina , Adulto , Animales , Bosnia y Herzegovina , Chlorocebus aethiops , Diagnóstico Diferencial , Enfermedades del Oído/diagnóstico , Quiste Epidérmico/diagnóstico , Humanos , Masculino , Personal Militar , Consulta Remota/métodos , Síndrome de Inmunodeficiencia Adquirida del Simio/diagnóstico , Virus de la Inmunodeficiencia de los Simios , Neoplasias Testiculares/diagnóstico , Varicocele/diagnóstico , Zoonosis
6.
Biochem J ; 176(1): 47-52, 1978 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-83141

RESUMEN

In certain lines of hepatoma tissue-culture cells, the extracellular glutamine concentration regulates the specific activity of glutamine synthetase. By quantifying the radioactivity in immunoprecipitated glutamine synthetase on polyacrylamide gels, we found that the rate of degradation, but not of synthesis, of glutamine synthetase is a sensitive function of extracellular glutamine. The activiy that degrades this enzyme appears to be labile.


Asunto(s)
Glutamato-Amoníaco Ligasa/metabolismo , Glutamina/farmacología , Neoplasias Hepáticas Experimentales/enzimología , Animales , Línea Celular , Cicloheximida/farmacología , Dactinomicina/farmacología , Glutamato-Amoníaco Ligasa/biosíntesis , Cinética
7.
J Biol Chem ; 253(17): 6125-31, 1978 Sep 10.
Artículo en Inglés | MEDLINE | ID: mdl-28325

RESUMEN

In certain lines of hepatoma tissue culture (HTC) cells, glutamine synthetase (EC 6.3.1.2) specific activity is increased 2.5- to 3-fold by the addition of glucocorticoids to the growth media. Actinomycin D blocks both the induction and deinduction of glutamine synthetase by glucocorticoids, suggesting a requirement of RNA synthesis for both processes. Using an antiserum raised against purified rat liver glutamine synthetase, we have precipitated radiolabeled glutamine synthetase from HTC cells. Electrophoresis of the immunoprecipitates on sodium didecyl sulfate-acrylamide gels isolates the subunit of glutamine synthetase and permits the radioactivity in the glutamine synthetase band to be quantitated. Using this technique, we have investigated the effect of dexamethasone, a synthetic glucocorticoid, on the rates of synthesis and degradation of glutamine synthetase. Dexamethasone (10(-7) M) increases the rate of synthesis of glutamine synthetase 2- to 3-fold but has no effect on the rate of glutamine synthetase degradation. The rates of total cell protein synthesis and degradation are not significantly affected by dexamethasone. The presence of actinomycin D at the time of removal of dexamethasone from induced cells prevents the fall in the induced rate of synthesis of glutamine synthetase normally seen when the inhibitor is removed from the culture medium. The regulation of glutamine synthetase by dexamethasone has been compared to the regulation of another dexamethasone-inducible enzyme in HTC cells, tyrosine aminotransferase, and been found to be similar in all parameters studied.


Asunto(s)
Carcinoma Hepatocelular/enzimología , Dexametasona/farmacología , Glutamato-Amoníaco Ligasa/metabolismo , Neoplasias Hepáticas/enzimología , Línea Celular , Relación Dosis-Respuesta a Droga , Inducción Enzimática/efectos de los fármacos , Glutamato-Amoníaco Ligasa/biosíntesis , Cinética
8.
Biochim Biophys Acta ; 447(2): 133-8, 1976 Oct 04.
Artículo en Inglés | MEDLINE | ID: mdl-184837

RESUMEN

The methylxanthines, caffeine and theophylline, inhibit postreplication repair of DNA in mammalian cells. Because they also inhibit cyclic AMP phosphodiesterase, it was thought that there might be some connection between concentrations of cyclic AMP and postreplication repair. We tested this possibility by performing DNA sedimentation experiments with a cyclic AMP-resistant mouse lymphoma cell mutant and its wild-type counterpart. The results show that there is no connection between cellular cyclic AMP concentrations and the rate of postreplication repair. Therefore, it is more likely that caffeine and theophylline inhibit postreplication repair by some other means, such as by binding to DNA.


Asunto(s)
Cafeína/farmacología , AMP Cíclico/farmacología , Reparación del ADN , Replicación del ADN/efectos de los fármacos , 3',5'-AMP Cíclico Fosfodiesterasas/metabolismo , Bucladesina/farmacología , Línea Celular , AMP Cíclico/metabolismo , Resistencia a Medicamentos , Teofilina/farmacología
11.
J Biol Chem ; 251(2): 334-43, 1976 Jan 25.
Artículo en Inglés | MEDLINE | ID: mdl-173716

RESUMEN

The binding of the "activated" receptor-glucocorticoid complexes of cultured rat hepatoma cells to nuclei, chromatin, and DNA has been studied under cell-free conditions. A critical factor in determining the shape of the binding curve is shown to be an inhibitory material which is present in crude cytosol and which can be removed without destroying the receptor-steroid complex. These and other results argue that the apparent saturation observed in earlier experiments may have been due to the inhibitors. Thus, the actual number of acceptor sites in hepatoma tissue culture cell nuclei is much larger than previously estimated and their affinity for the complex is lower. Nuclear binding experiments indicate that the inhibitory material interacts with the receptor-steroid complex. The inhibitors appear to be macromolecular; but their effects cannot be mimicked by albumin or hemoglobin. The acceptor capacity at low ionic strength for binding receptor-glucocorticoid complexes increases when proceeding from nuclei to DNA. An analysis of the kinetics of association and dissociation and of the relative binding behavior of nuclei and DNA argues that the affinity of complex for nuclei is much greater than for DNA. DNA-associated histones reduce the amount of complex that binds to DNA. These and perhaps other chromosomal proteins may be responsible for the ordering of acceptor capacity. Evidence is presented that the difference in affinities of nuclear and DNA acceptors could also be due to chromosomal proteins. In nuclei, these proteins may thus both reduce the amount of complex binding by rendering regions of DNA less accessible and increase the binding affinity of some, or all, of those DNA binding sites which remain exposed.


Asunto(s)
Glucocorticoides/metabolismo , Proteínas de Neoplasias/metabolismo , Receptores de Superficie Celular , Esteroides/metabolismo , Sitios de Unión , Línea Celular , Núcleo Celular/metabolismo , Cromatina/metabolismo , Computadores , Citosol/metabolismo , ADN de Neoplasias/metabolismo , Cinética , Matemática , Modelos Biológicos , Unión Proteica
12.
Proc Natl Acad Sci U S A ; 72(12): 5051-5, 1975 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-174091

RESUMEN

Compared to the wild-type parental line of S49 mouse lymphoma cells, intact cells of a mutant line (kin.A) are 10-fold less sensititive to biologic effects of exogenous cyclic adenosine 3':5'-monophophosphate (cAMP), such as induction of cAMP phosphodiesterase, cell cycle-specific growth inhibition, and cytolysis. The cAMP-dependent protein kinase (ATP:protein phosphotransferase; EC 2.7.1.37) activity of kin.A cells exhibits an apparent Ka for activation by cAMP 10-fold greater than that of wild type, and is much more resistant to inactivation by heat. These differences between the wild-type and mutant enzymes persist through a high degree of purification, suggesting a structural alteration in the kin.A holoenzyme. Heterologous reconstitution experiments, using separated R and C subunits of the wild-type and kin.A cAMP-dependent kinases, show that the altered cAMP affinity and thermolability are conferred by the R component of the kin.A enzyme. These results are most consistent with a structural mutation in the kin.A gene coding for the R subunit of cAMP-dependent protein kinase. Evidence for a structural mutation helps to define one mechanism of heritable variation in cultured somatic cells. The phenotype produced by the kin.A structural mutation also greatly strengthens the conslusion that cAMP-dependent protein kinase is essential for cAMP regulation of growth and enzyme induction in intact S49 cells.


Asunto(s)
Genes , Proteínas Quinasas/biosíntesis , Línea Celular , AMP Cíclico/metabolismo , AMP Cíclico/farmacología , Estabilidad de Medicamentos , Activación Enzimática/efectos de los fármacos , Heterocigoto , Homocigoto , Calor , Cinética , Mutación , Biosíntesis de Proteínas , Desnaturalización Proteica , Proteínas Quinasas/aislamiento & purificación , Proteínas Quinasas/metabolismo , Receptores de Droga , Transcripción Genética
13.
Cell ; 6(3): 299-305, 1975 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-212202

RESUMEN

We have investigated the mechanisms by which dexamethasone (a synthetic glucocorticoid) stimulates the production of mouse mammary tumor virus (MMTV) by cell cultures derived from mammary carcinomas of GR mice. Treatment of these cells with dexamethasone stimulates a rapid accumulation of intracellular virus-specific RNA which is dependent upon RNA synthesis but not upon DNA or protein synthesis. The effect of dexamethasone is probably mediated by a specific and saturable glucocorticoid receptor. We conclude that the accumulation of MMTV RNA is a primary response to dexamethasone and that the rate of synthesis of MMTV RNA is probably accelerated by treatment with dexamethasone.


Asunto(s)
Dexametasona/farmacología , Virus del Tumor Mamario del Ratón/genética , ARN Viral/biosíntesis , Línea Celular , Cicloheximida/farmacología , ADN Viral/biosíntesis , Dactinomicina/farmacología , Dexametasona/antagonistas & inhibidores , Cinética , Receptores de Glucocorticoides/efectos de los fármacos , Replicación Viral/efectos de los fármacos
14.
Science ; 190(4217): 896-8, 1975 Nov 28.
Artículo en Inglés | MEDLINE | ID: mdl-171770

RESUMEN

Dibutyryl cyclic adenosine 3',5'-monophosphate (cyclic AMP) produces phosphodiesterase induction, growth arrest, and cytolysis in S49 lymphoma cells. The striking parallelism between protein kinase activity that is dependent on cytosol cyclic AMP and cellular responses to dibutyryl cyclic AMP in wild-type cells and three classes of clones resistant to cyclic AMP indicates that protein kinase mediates cyclic AMP regulation of growth and enzyme induction in S49 cells.


Asunto(s)
AMP Cíclico/metabolismo , Proteínas Quinasas/metabolismo , 3',5'-AMP Cíclico Fosfodiesterasas/biosíntesis , 3',5'-AMP Cíclico Fosfodiesterasas/metabolismo , Bucladesina/farmacología , División Celular , Células Cultivadas , Inducción Enzimática , Histonas/metabolismo , Linfoma , Mutación
15.
Proc Natl Acad Sci U S A ; 72(10): 3849-52, 1975 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-172887

RESUMEN

A simple method for purification of the glucocorticoid receptor from hepatoma tissue culture cells has been developed. The procedure, which requires only about 24 hr, involves biospecific adsorption of the receptor to deoxycorticosterone derivatized agarose, elution with a glucocorticoid, and gel filtration. The receptor-steroid complex is obtained in 35-40% yield and is about 2000-fold purified. It possesses properties similar to those reported in crude extracts, including sedimentation coefficient in glycerol gradients and activation-dependent binding to nuclei.


Asunto(s)
Glucocorticoides/metabolismo , Proteínas de Neoplasias/aislamiento & purificación , Receptores de Superficie Celular , Sitios de Unión , Carcinoma Hepatocelular/análisis , Carcinoma Hepatocelular/metabolismo , Línea Celular , Cromatografía de Afinidad , Dexametasona/metabolismo , Neoplasias Hepáticas , Peso Molecular , Proteínas de Neoplasias/metabolismo , Unión Proteica , Tetrahidrocortisol/metabolismo , Triamcinolona Acetonida/metabolismo
16.
Am J Pathol ; 81(1): 199-204, 1975 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-170834

RESUMEN

A mouse lymphoma tissue culture line, S49, is killed by isoproterenol, choleratoxin, or prostaglandin E1, inducers of cyclic AMP (cAMP) in these cells, or by the analog dibutyryl (db) cAMP. Cell death follows arrest in the G1 phase of the cell cycle. Mutant subclones obtained by growing S49 with dbcAMP were resistant to killing. They were deficient in cAMP-dependent protein kinase. These results are discussed in relation to the possible physiologic role of cAMP-induced cell death in T-cell differentiation.


Asunto(s)
AMP Cíclico/farmacología , Linfoma , Animales , Bucladesina/farmacología , División Celular , Línea Celular , Supervivencia Celular , Células Cultivadas/efectos de los fármacos , Cólera , Técnicas In Vitro , Isoproterenol/farmacología , Cinética , Ratones , Mutación , Prostaglandinas E/farmacología , Proteínas Quinasas/metabolismo , Linfocitos T/efectos de los fármacos , Toxinas Biológicas/farmacología
18.
J Biol Chem ; 250(15): 6015-21, 1975 Aug 10.
Artículo en Inglés | MEDLINE | ID: mdl-168206

RESUMEN

DNA has been implicated as the nuclear acceptor for receptor-glucocorticoid complexes. The present study concerns the interaction of these complexes, isolated from cultured rat hepatoma cells, with purified DNA. This association is rapid, reaching a maximum within a few minutes at 0 degrees, whereas dissociation requires several hours. DNA binds neither free glucocorticoids nor those complexed with transcortin or cytosol proteins different from the receptor. Receptors which are not complexed by steroid have little or no affinity for DNA. "Activation," necessary for the binding of receptor-steroid complexes to isolated nuclei, also enhances DNA binding. The capacity of DNA for binding receptor-steroid complexes is large; saturation was not observed at the complex concentrations studied, using either crude or partially purified receptor preparations. The association of complexes with DNA is inhibited by divalent cations, at increasing ionic strengths, and by mercurial reagents. Complexes bind equally well to bacterial, bacteriophage, or rat DNA; however, there was either no or substantially reduced binding by bacterial 23 S rRNA. The binding of complexes to native DNA is roughly 3-fold greater than to denatured DNA. These characteristics are consistent with the possibility that DNA is the nuclear acceptor for receptor-glucocorticoid complexes; however, the actual composition of the acceptor sites remains unknown.


Asunto(s)
Carcinoma Hepatocelular/metabolismo , ADN/metabolismo , Dexametasona/metabolismo , Hidrocortisona/metabolismo , Receptores de Superficie Celular , Animales , Sitios de Unión , Células Cultivadas , Cloromercuribenzoatos/farmacología , Cromatografía en Gel , Medios de Cultivo , Citosol/metabolismo , Cinética , Neoplasias Hepáticas , Proteínas de Neoplasias/metabolismo , Neoplasias Experimentales/metabolismo , Desnaturalización de Ácido Nucleico , Unión Proteica , ARN , Ratas , Temperatura , Factores de Tiempo
19.
Aust J Exp Biol Med Sci ; 53(4): 257-63, 1975 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-779741

RESUMEN

An improved medium for the isolation of Mycoplasma species from contaminated cell cultures is reported. A modification of the mycoplasma detection method using the uridine/uracil uptake ratio method is described. Results obtained using this method with mycoplasma contaminated cell cultures and with contaminated cell cultures treated with the antibiotic Lincomycin are presented.


Asunto(s)
Técnicas Bacteriológicas , Células Cultivadas/microbiología , Mycoplasma/aislamiento & purificación , Animales , Células Cultivadas/metabolismo , Medios de Cultivo , Caballos , Humanos , Lincomicina/farmacología , Mycoplasma/efectos de los fármacos , Uracilo/metabolismo , Uridina/metabolismo
20.
J Cell Physiol ; 85(3): 611-20, 1975 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-167037

RESUMEN

N-6,O-2'-dibutyryl adenosine 3',5'-monophosphate kills cultured mouse lymphosarcoma cells, but not resistant mutants derived by a single-step clonal selection. Resistant clones lack the cyclic AMP binding proteins present in wild type, cyclic AMP sensitive clones. Both endogenous cyclic AMP, accumulated in response to isoproterenol or cholera toxin, and exogenous dibutyryl cyclic AMP induce cyclic AMP phosphodiesterase, slow growth, and eventually kill wild type cells. In the resistant mutants, however, the endogenous and exogenous cyclic nucleotides appear to be completely inactive. These results indicate that an intracellular receptor for cyclic AMP, previously shown to be associated with a cyclic AMP-dependent protein kinase, mediates cyclic AMP's regulation of growth and phosphodiesterase synthesis.


Asunto(s)
AMP Cíclico/fisiología , Linfoma , Biología Molecular , Mutación , 3',5'-AMP Cíclico Fosfodiesterasas/biosíntesis , Bucladesina/farmacología , División Celular/efectos de los fármacos , Línea Celular , AMP Cíclico/metabolismo , Resistencia a Medicamentos , Isoproterenol/farmacología , Linfoma/enzimología , Linfoma/metabolismo , Linfoma/patología , Prostaglandinas E/farmacología , Selección Genética , Fracciones Subcelulares/metabolismo
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA