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1.
Dis Esophagus ; 29(4): 320-5, 2016 May.
Artículo en Inglés | MEDLINE | ID: mdl-25707341

RESUMEN

This study aimed to determine the impact of preoperative staging on the treatment of clinical T2N0 (cT2N0) esophageal cancer patients undergoing esophagectomy. We reviewed a retrospective cohort of 27 patients treated at a single institution between 1999 and 2011. Clinical staging was performed with computed tomography, positron emission tomography, and endoscopic ultrasound. Patients were separated into two groups: neoadjuvant therapy followed by surgery (NEOSURG) and surgery alone (SURG). There were 11 patients (41%) in the NEOSURG group and 16 patients (59%) in the SURG group. In the NEOSURG group, three of 11 patients (27%) had a pathological complete response and eight (73%) were partial or nonresponders after neoadjuvant therapy. In the SURG group, nine of 16 patients (56%) were understaged, 6 (38%) were overstaged, and 1 (6%) was correctly staged. In the entire cohort, despite being clinically node negative, 14 of 27 patients (52%) had node-positive disease (5/11 [45%] in the NEOSURG group, and 9/16 [56%] in the SURG group). Overall survival rate was not statistically significant between the two groups (P = 0.96). Many cT2N0 patients are clinically understaged and show no preoperative evidence of node-positive disease. Consequently, neoadjuvant therapy may have a beneficial role in treatment.


Asunto(s)
Adenocarcinoma , Neoplasias Esofágicas , Esofagectomía , Adenocarcinoma/mortalidad , Adenocarcinoma/patología , Adenocarcinoma/cirugía , Adulto , Anciano , Quimioradioterapia Adyuvante/métodos , Neoplasias Esofágicas/mortalidad , Neoplasias Esofágicas/patología , Neoplasias Esofágicas/cirugía , Esofagectomía/métodos , Esofagectomía/estadística & datos numéricos , Esofagoscopía/métodos , Femenino , Humanos , Metástasis Linfática , Masculino , Persona de Mediana Edad , Estadificación de Neoplasias , Evaluación de Procesos y Resultados en Atención de Salud , Tomografía de Emisión de Positrones/métodos , Periodo Preoperatorio , Tasa de Supervivencia , Tomografía Computarizada por Rayos X/métodos , Estados Unidos/epidemiología
2.
Dis Esophagus ; 29(6): 614-20, 2016 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-26043837

RESUMEN

Trimodality therapy for resectable esophageal and gastroesophageal junction cancers utilizing preoperative radiotherapy with concurrent carboplatin and paclitaxel-based chemotherapy is being increasingly utilized secondary to the results of the phase III CROSS trial. However, there is a paucity of reports of this regimen as a component of chemoradiotherapy in North America. We aim to report on our clinical experience using a modified CROSS regimen with higher radiotherapy doses. Patients with advanced (cT2-cT4 or node positive) esophageal or gastroesophageal junction carcinoma who received preoperative carboplatin/paclitaxel-based chemoradiotherapy with radiation doses of greater than 41.4 Gray (Gy) followed by esophagectomy were identified from an institutional database. Patient, imaging, treatment, and tumor response characteristics were analyzed. Twenty-four patients were analyzed. All but one tumor had adenocarcinoma histology. The median radiation dose was 50.4 Gy. Pathologic complete response was achieved in 29% of patients, with all receiving 50.4 Gy. Three early postoperative deaths were seen, due in part to acute respiratory distress syndrome and all three patients received 50-50.4 Gy. With a median follow-up of 9.4 months (23 days-2 years), median survival was 24 months. Trimodality therapy utilizing concurrent carboplatin/paclitaxel with North American radiotherapy doses appeared to have similar pathologic complete response rates compared with the CROSS trial, but may be associated with higher toxicity. Although the sample size is small and further follow-up is necessary, radiation doses greater than 41.4 Gy may not be warranted secondary to a potentially increased risk of severe radiation-induced acute lung injury.


Asunto(s)
Adenocarcinoma/terapia , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Carcinoma de Células Escamosas/terapia , Quimioradioterapia , Neoplasias Esofágicas/terapia , Esofagectomía , Unión Esofagogástrica/cirugía , Terapia Neoadyuvante , Adenocarcinoma/patología , Adulto , Anciano , Carboplatino/administración & dosificación , Carcinoma de Células Escamosas/patología , Neoplasias Esofágicas/patología , Carcinoma de Células Escamosas de Esófago , Unión Esofagogástrica/patología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estadificación de Neoplasias , Paclitaxel/administración & dosificación , Dosificación Radioterapéutica , Estudios Retrospectivos , Resultado del Tratamiento
3.
Oecologia ; 177(4): 1093-102, 2015 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-25676106

RESUMEN

Agri-environment schemes have been implemented across the European Union in order to reverse declines in farmland biodiversity. To assess the impact of these schemes for bumblebees, accurate measures of their populations are required. Here, we compared bumblebee population estimates on 16 farms using three commonly used techniques: standardised line transects, coloured pan traps and molecular estimates of nest abundance. There was no significant correlation between the estimates obtained by the three techniques, suggesting that each technique captured a different aspect of local bumblebee population size and distribution in the landscape. Bumblebee abundance as observed on the transects was positively influenced by the number of flowers present on the transect. The number of bumblebees caught in pan traps was positively influenced by the density of flowers surrounding the trapping location and negatively influenced by wider landscape heterogeneity. Molecular estimates of the number of nests of Bombus terrestris and B. hortorum were positively associated with the proportion of the landscape covered in oilseed rape and field beans. Both direct survey techniques are strongly affected by floral abundance immediately around the survey site, potentially leading to misleading results if attempting to infer overall abundance in an area or on a farm. In contrast, whilst the molecular method suffers from an inability to detect sister pairs at low sample sizes, it appears to be unaffected by the abundance of forage and thus is the preferred survey technique.


Asunto(s)
Agricultura , Abejas , Biodiversidad , Ecología/métodos , Ecosistema , Flores , Animales , Biomasa , Brassica napus , Europa (Continente) , Fabaceae , Femenino , Densidad de Población , Especificidad de la Especie
4.
Aging Ment Health ; 16(3): 305-16, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-22394319

RESUMEN

OBJECTIVES AND METHOD: Information about aging-related change in coping is limited mainly to results of cross-sectional studies of age differences in coping, and no research has focused on predictors of aging-related change in coping behavior. To extend research in this area, we used longitudinal multilevel modeling to describe older adults' (n = 719; baseline M = 61 years) 20-year, intraindividual approach and avoidance coping trajectories, and to determine the influence of two sets of predictors (threat appraisal and stressor characteristics; gender and baseline personal and social resources) on level and rate of change in these trajectories. RESULTS: Over the 20-year study interval, participants declined in the use of approach coping and most avoidance coping strategies, but there was significant variation in this trend. In simultaneous predictive models, female gender, more threat appraisal, stressor severity, social resources, and depressive symptoms, and fewer financial resources were independently associated with higher initial levels of coping responses. Having more social resources, and fewer financial resources, at baseline in late-middle-age predicted faster decline over time in approach coping. Having more baseline depressive symptoms, and fewer baseline financial resources, hastened decline in use of avoidance coping. Independent of other variables in these models, decline over time in approach coping and avoidance coping remained statistically significant. CONCLUSION: Overall decline in coping may be a normative pattern of coping change in later life. However, it also is modifiable by older adults' stressor appraisals, their stressors, and the personal and social resources they possess at entry to later life, in late-middle-age.


Asunto(s)
Adaptación Psicológica , Envejecimiento/psicología , Apoyo Social , Anciano , Depresión/epidemiología , Femenino , Predicción , Humanos , Estudios Longitudinales , Masculino , Persona de Mediana Edad , Factores Sexuales , Clase Social , Estrés Psicológico
5.
J Exp Med ; 156(4): 1025-41, 1982 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-7153707

RESUMEN

It has previously been shown that mice exposed to ultraviolet radiation (UV) fail to reject highly immunogenic UV-induced tumors, which are regularly rejected by normal mice. The present study shows, however, that this immunosuppresion is incomplete, as UV-treated mice can still mount certain tumor-specific immune responses and reject smaller inocula of tumor cells that regularly grow progressively in athymic nude mice. Furthermore, all tumor cell lines that were reisolated from the tumor mass resulting from one tumor passage through UV-treated recipients heritably lost a tumor-specific determinant present on the parental tumor cells used for transplantation, and a large percentage of these reisolated variant tumors had changed to progressively growing tumors, in that they were no longer rejected by normal mice. In contrast, none of the tumors reisolated from passage through athymic nude mice or anti-idiotypically suppressed mice showed this change in antigenicity and progressive growth behavior. Thus, it appears that the phenotypic change in tumors reisolated from UV-treated mice was caused by immunoselection, and that the tumor-specific immunity in these mice apparently restrained the outgrowth of the parental tumor cells despite the partial immunosuppression. Because of the regularity at which tumor variants arose in the UV-treated mice after tumor transplantation, it appears that the partial immunosuppression caused by UV-treatment may have favored the outgrowth of antigenic variants from the parental tumor cell population, possibly by allowing more time for the generation of tumor variants. A similar immunoselection process might be part of tumor progression during tumor development and preferentially occur in cancer-bearing individuals showing concomitant tumor immunity.


Asunto(s)
Terapia de Inmunosupresión , Neoplasias Experimentales/inmunología , Animales , Antígenos de Neoplasias/inmunología , Variación Genética , Rechazo de Injerto , Ratones , Ratones Desnudos , Trasplante de Neoplasias , Rayos Ultravioleta
6.
J Exp Med ; 155(2): 557-73, 1982 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-6977009

RESUMEN

The ultraviolet radiation-induced fibrosarcoma 1591 generally is rejected by normal syngeneic mice and only rarely exhibits progressive growth. We isolated five of these rare progressor tumors from normal animals to determine the selective pressures that had been exerted upon the parental tumor by normal immunocompetent hosts. We found that the variant tumor cell lines could neither induce nor be killed by tumor-specific lymphocytes, suggesting that selection had been exerted against tumor cells expressing the tumor-specific antigen. In contrast, no selection against natural killer cell activity or against nonspecific T cell-mediated immunity seems to have occurred because progressor tumor cells were highly sensitive to these types of effector cells and in fact induced these effector cells more effectively than did the parental tumor. Nude mice were found to be as capable as normal mice in generating natural killer activity in response to a challenge with progressor tumor cells, but they were unable to mount a nonspecific T lymphocyte response. This may account for the fact that the progressor tumors grew at a significantly faster rate in nude animals than in normal mice. Thus, our study shows that in this tumor system nonspecific T cell-mediated immunity may play a role in retarding tumor growth, but the absolute resistance of normal animals to progressive tumor growth critically depends upon the presence of T cell-mediated tumor-specific immunity. Furthermore, neither NK cells nor nonspecific cytotoxic T lymphocytes appear to play a role in immunoselection against this tumor in normal immunocompetent hosts.


Asunto(s)
Transformación Celular Neoplásica , Fibrosarcoma/genética , Variación Genética , Selección Genética , Animales , Antígenos Ly/inmunología , Citotoxicidad Inmunológica , Femenino , Fibrosarcoma/inmunología , Sueros Inmunes/farmacología , Inmunidad Celular , Ratones , Ratones Endogámicos C3H , Ratones Desnudos , Regresión Neoplásica Espontánea , Trasplante de Neoplasias , Linfocitos T/inmunología
7.
J Natl Cancer Inst ; 56(1): 193-5, 1976 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-1255747

RESUMEN

The formation of tumor colonies was compared in the lungs of athymic nude and normal littermate mice after an iv injection of transplantable syngeneic tumor cells. Each of 5 tumors tested formed fewer colonies in the lungs of nude recepients.


Asunto(s)
Neoplasias Pulmonares/inmunología , Animales , Femenino , Masculino , Ratones , Metástasis de la Neoplasia/inmunología , Trasplante de Neoplasias , Células Neoplásicas Circulantes
8.
Biodivers Conserv ; 25(13): 2655-2671, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-32355425

RESUMEN

Changes in agricultural practice across Europe and North America have been associated with declines in wild bee populations. Bee diet breadth has been associated with sensitivity to agricultural intensification, but much of this analysis has been conducted at the categorical level of generalist or specialist, and it is not clear to what extent the level of generalisation within generalist species is also associated with species persistence. We used pollen load analysis to quantify the pollen diets of wild solitary bees on 19 farms across southern England, UK. A total of 72 species of solitary bees were recorded, but only 31 species were abundant enough to allow for formal diet characterisation. The results broadly conformed to existing literature with the majority of species polylectic and collecting pollen from a wide range of plants. Pollen load analysis consistently identified pollens from more plant species and families from each bee species than direct observation of their foraging behaviour. After rarefaction to standardise pollen load sample sizes, diet breadth was significantly associated with frequency of occurrence, with more generalist bees present on more farms than less generalist bees. Our results show that the majority of bee species present on farmland in reasonable numbers are widely variable in their pollen choices, but that those with the broadest diet were present on the greatest number of farms. Increasing the diversity of plants included in agri-environment schemes may be necessary to provide a wider range of pollen resources in order to support a diverse bee community on farmland.

9.
Arch Gen Psychiatry ; 38(12): 1377-81, 1981 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-7316683

RESUMEN

It is widely believed among psychiatrists and laymen alike that Christmas and other holidays are associated with an increased incidence of psychopathology. Statistical studies, however, consistently have been shown the Christmas season to be associated with a low incidence of suicide and psychiatric hospitalization. The present study examines the number and type of visits to a 24-hour psychiatric emergency service over a seven-year period. There is a decrease in the number of visits during the days and weeks before Christmas and an increase of roughly the same magnitude afterward. The effect is more prominent for women and older persons but does not seem to differentially affect persons of different racial, marital, or diagnostic status.


Asunto(s)
Vacaciones y Feriados , Trastornos Mentales/epidemiología , Adulto , Factores de Edad , Servicios de Urgencia Psiquiátrica , Femenino , Humanos , Masculino , Trastornos Mentales/psicología , North Carolina , Factores Sexuales , Estrés Psicológico
10.
J Invest Dermatol ; 92(3): 315-20, 1989 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-2465357

RESUMEN

Minoxidil, a potent vasodilator, stimulates the growth of terminal hair from vellus or miniaturized follicles in balding scalp. To study minoxidil's action on isolated follicles we developed and validated an organ culture system using mouse whisker follicles. Control follicles cultured without minoxidil showed macroscopic changes including kinking of the hair shafts and bending of the follicles. Necrosis was evident in the differentiating epithelial elements forming the cuticle, cortex, and inner root sheath. These abnormalities were eliminated or greatly reduced in minoxidil-treated follicles. The morphology of these follicles was consistent with the production of new hair during culture. Direct measurement demonstrated that minoxidil-treated follicles grew significantly longer than control follicles during the 3-d culture. Minoxidil increased the incorporation of radiolabeled cysteine and glycine in follicles compared with control treatment. Doses of minoxidil up to 1 mM caused increased cysteine incorporation, while higher doses were inhibitory. Experiments with labeled thymidine indicated that minoxidil induced proliferation of hair epithelial cells near the base of the follicle. Autoradiography also showed that cysteine accumulated in the keratogenous zone above the dermal papilla. These studies demonstrate that organ cultured follicles are suitable for determining minoxidil's mechanism of action and may be useful for studying other aspects of hair biology. The results also show that minoxidil's effect on hair follicles is direct. This suggests that minoxidil's action in vivo includes more than just increasing blood flow to hair follicles.


Asunto(s)
Minoxidil/farmacología , Vibrisas/efectos de los fármacos , Animales , Diferenciación Celular/efectos de los fármacos , Cisteína/metabolismo , Epidermis/efectos de los fármacos , Glicina/metabolismo , Queratinas , Ratones , Necrosis , Técnicas de Cultivo de Órganos , Timidina/metabolismo , Vibrisas/crecimiento & desarrollo , Vibrisas/fisiología
11.
Am J Psychiatry ; 140(4): 459-62, 1983 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-6837785

RESUMEN

Twenty-two suicides were identified in a series of 5,284 psychiatric emergency room patients, yielding a suicide rate of 111.1 per 100,000 "patient-years at risk"--more than seven times the age- and sex-adjusted rate for the general population. Subpopulations at high risk were white people, men, depressed and schizophrenic patients, substance abusers, and patients with multiple emergency room visits. No patients had killed themselves immediately after an emergency room visit, but several had killed themselves without following through on a referral from the emergency room to another facility for treatment. The authors discuss the implications of these findings for emergency room practice and for further research.


Asunto(s)
Servicios de Urgencia Psiquiátrica , Trastornos Mentales/psicología , Servicios de Salud Mental , Suicidio/epidemiología , Adulto , Factores de Edad , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , North Carolina , Cooperación del Paciente , Riesgo , Factores Sexuales
12.
Environ Health Perspect ; 38: 149-55, 1981 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-7238444

RESUMEN

A procedure for quantitative analysis of skin carcinogenesis data, for the purpose of establishing carcinogenic potency, has been applied to observations obtained from C3H mice exposed continuously to synthetic and natural petroleums. The importance of total polynuclear aromatic (PNA) content to the skin carcinogenic activity of the crude materials was also examined. Of three synthetic petroleums evaluated, all were shown capable of inducing skin neoplasms within a two-year exposure period. Under comparable exposure conditions a composite sample of five natural petroleums was noncarcinogenic. Comparison of the distributions of times to initial skin neoplasm versus dose rate, for groups exposed to synthetic fossil liquids and the reference skin carcinogen, benzo(a)pyrene, provided estimates of relative carcinotenic potency for the synthetic petroleums ranging from 1/500 to 1/1400 the potency of benzo(a)pyrene. The carcinogenic activity of a chemically isolated PNA fraction versus the crude from which it was derived suggested that this fraction was responsible for the carcinogenic activity of these synthetic petroleums in mouse skin.


Asunto(s)
Carcinógenos , Petróleo/efectos adversos , Neoplasias Cutáneas/inducido químicamente , Animales , Femenino , Aceites Combustibles/efectos adversos , Aceites Combustibles/toxicidad , Masculino , Ratones , Ratones Endogámicos C3H , Neoplasias Experimentales/inducido químicamente , Petróleo/toxicidad
13.
Radiat Res ; 119(2): 246-60, 1989 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-2756116

RESUMEN

The effects of 3 mM caffeine on cell cycle progression of HeLa S3 cells exponentially and asynchronously growing in suspension culture were studied following exposure to 6.8 Gy gamma irradiation or 30 min at 45 degrees C hyperthermia. The stathmokinetic method, in which cells are grown in the presence of colcemid for the duration of experiment, in combination with two flow cytometric techniques, propidium iodide staining of DNA and acridine orange staining following acid denaturation of chromatin, were used to determine the fraction of cells in four cell cycle compartments, G1, S, G2, and M. Radiation and caffeine acted in a complementary manner, in which radiation reduced the caffeine-induced delays in cell cycle progression and caffeine prevented completely the radiation-induced accumulation of cells in G2 and mitotic delay. Heat and caffeine had additive effects on alterations in cell cycle progression. Cells containing spontaneous prematurely condensed chromatin were observed transiently immediately following heat exposure. These cells appeared to be in G2 and late S phase.


Asunto(s)
Cafeína/farmacología , Ciclo Celular , Calor , Ciclo Celular/efectos de los fármacos , Ciclo Celular/efectos de la radiación , Radioisótopos de Cesio , Demecolcina/farmacología , Citometría de Flujo , Rayos gamma , Células HeLa , Humanos , Mitosis
14.
Radiat Res ; 122(2): 197-208, 1990 May.
Artículo en Inglés | MEDLINE | ID: mdl-2336466

RESUMEN

A method was developed to determine the synthesis of nuclear proteins throughout the cell cycle which was resolved into six compartments on the basis of DNA and nuclear protein content (i.e., early and late G1, early and late S, etc). Using this technique cell-cycle-specific synthesis of certain nuclear proteins was observed. Of particular interest was a 170-kDa protein(s) whose synthesis was initiated in early S phase and reached a maximum rate in late G2. Following irradiation with 6.8 Gy of 137Cs gamma rays the synthesis of the 170-kDa protein(s) declined in the G2 population with near total inhibition seen by 24 h. Synthesis of the 170-kDa protein(s) appeared to be slightly enhanced, and the postirradiation inhibition of its synthesis was reversed, in the presence of 3 mM caffeine. Also, the synthesis of 55-kDa nuclear protein(s) was stimulated throughout the cell cycle in the presence of 3 mM caffeine. These observations suggest new possibilities regarding the mechanism of the X-ray-induced G2 block and its reversal by caffeine. However, the exact role of these nuclear proteins in cellular events remains to be ascertained.


Asunto(s)
Interfase/efectos de la radiación , Proteínas Nucleares/biosíntesis , Cafeína/farmacología , Radioisótopos de Cesio , Rayos gamma , Células HeLa/efectos de los fármacos , Células HeLa/metabolismo , Células HeLa/efectos de la radiación , Humanos , Interfase/efectos de los fármacos , Estimulación Química
15.
Ann Thorac Surg ; 39(3): 282, 1985 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-3977474

RESUMEN

Postpneumonectomy paraplegia developed in a woman admitted for resection of bronchogenic carcinoma. Postpneumonectomy paraplegia is an uncommon, but catastrophic, event that is thought to be caused primarily by ischemia to the spinal cord; in this instance an epidural hematoma was the cause. Recommendations for prevention are presented.


Asunto(s)
Hematoma Epidural Craneal/complicaciones , Paraplejía/etiología , Neumonectomía/efectos adversos , Compresión de la Médula Espinal/etiología , Carcinoma de Células Escamosas/cirugía , Femenino , Hematoma Epidural Craneal/cirugía , Humanos , Neoplasias Pulmonares/cirugía , Persona de Mediana Edad , Paraplejía/cirugía
16.
Urology ; 5(4): 492-5, 1975 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-1129866

RESUMEN

Two children with priapism are presented; one case was secondary to trauma and the other was idiopathic in nature. Both boys were effectively treated by bilateral corporosaphenous shunts. The mechanism of normal erection and the pathophysiology of priapism are discussed.


Asunto(s)
Priapismo/cirugía , Vena Safena/cirugía , Adolescente , Anemia de Células Falciformes/complicaciones , Niño , Humanos , Leucemia/complicaciones , Masculino , Pene/irrigación sanguínea , Pene/fisiopatología , Priapismo/etiología , Priapismo/fisiopatología , Heridas y Lesiones/complicaciones
17.
Toxicology ; 21(1): 47-57, 1981.
Artículo en Inglés | MEDLINE | ID: mdl-6269255

RESUMEN

An in vitro method for studying the interaction between tritiated benzo[a]pyrene ([3H]BP) and intact mouse skin was investigated. [3H]BP was applied to the epidermal surface of the skin floating on medium, and radioactivity in the medium was measured periodically. After 48-h incubation, about 45% of the radioactivity was in the medium; of this amount, about 80% accumulated during the first 24 h. Incubation temperature, metabolic inhibitors, and the amount of BP applied caused pronounced effects on accumulation; slight to moderate effects were noted for the type and volume of medium and vehicle used. Results of the temperature and inhibitor experiments indicated that accumulation of radioactivity depended on cell viability. About 80% of the radioactivity in the medium was water soluble, showing that biotransformation of BP by skin cells occurred. We are using the skin organ culture method to help understand the interaction of mammalian skin with hydrocarbon mixtures. A study of these interactions may lead to metabolic, cytotoxic, and macromolecular-binding profiles that characterize a carcinogenic mixture of hydrocarbons.


Asunto(s)
Benzopirenos/farmacología , Piel/efectos de los fármacos , Animales , Azidas/farmacología , Benzo(a)pireno , Medios de Cultivo , Cinética , Masculino , Ratones , Ratones Endogámicos C3H , Técnicas de Cultivo de Órganos , Piel/patología , Solubilidad
18.
Mutat Res ; 51(1): 77-84, 1978 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-209324

RESUMEN

Host-mediated assays have been developed to allow determination of the mutagenic potential of promutagens and procarcinogens which require metabolic activation to exert their effects on indicator organisms. We report here the development of the host-(mouse)-mediated CHO/HGPRT system using the procarcinogen dimethylnitrosamine (DMN) as a model agent. Using a 2--h treatment time, we observed a linear dose-response relationship up to 250 mg of DMN per kg body weight. At 100 and 500 mg/kg DMN, mutation induction increased with time up to at least 6 h. DMN was not mutagenic when tested in vitro. Athymic (nude) mice, their phenotypically normal littermates, or BALB/c mice of both sexes were found to be suitable as hosts. A time- and dose-dependency of induced mutation frequency by a direct-acting agent, ethyl methanesulfonate (EMS), was observed in both the in vitro and the host-mediated assays.


Asunto(s)
Dimetilnitrosamina/farmacología , Metanosulfonato de Etilo/farmacología , Mesilatos/farmacología , Mutágenos , Nitrosaminas/farmacología , Animales , Células Clonales , Relación Dosis-Respuesta a Droga , Femenino , Técnicas Genéticas , Hipoxantina Fosforribosiltransferasa/genética , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos
19.
Clin Dermatol ; 6(4): 159-62, 1988.
Artículo en Inglés | MEDLINE | ID: mdl-3063369

RESUMEN

A genetic model of androchronogenic alopecia has yet to be described in the rat or mouse, two of the better characterized species. It may be relevant that the best current animal model of androchronogenic alopecia, the stumptailed macaque, is a primate. The age of onset and the pattern of hair loss closely resemble human male-pattern baldness and morphologically, as well as mechanistically, may be analogous to the corresponding process in humans. Since genetically controlled regional hairlessness is a phenomenon relatively unique to Homo sapiens, it may be too much to expect to find an analogous process among rodents.


Asunto(s)
Alopecia/genética , Modelos Animales de Enfermedad , Alopecia/etiología , Animales , Femenino , Cabello/crecimiento & desarrollo , Masculino , Ratones , Minoxidil/administración & dosificación , Minoxidil/farmacología , Mutación , Ratas , Piel/patología
20.
J Biochem Biophys Methods ; 3(5): 285-91, 1980 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-6160174

RESUMEN

The fluorescence associated with benzo[a]pyrene [BP] moieties covalently attached to the nucleic acid (DNA plus RNA) isolated from the epidermis of BP-treated mice was examined at 77 K in frozen aqueous solutions by use of a photon-counting fluorimeter operating in the synchronous scanning mode. The excitation and emission wavelengths were scanned simultaneously with the monochromators set 28 nm apart. This setting coincides with the difference in wavelength between the excitation and emission maxima for the fluorescence of bound BP. Currently the level of detection is in the order of 1 BP residue per 200,000 bases in 40 microgram of nucleic acid. This amount of nucleic acid can be isolated from the skin of a single mouse. The method described here is generally useful for detecting the binding to DNA of nonradioactive carcinogenic polynuclear aromatic which might occur following the topical application to animal skin in vivo of complex hydrocarbon mixtures such as synthetic fuels and crude oils.


Asunto(s)
Benzopirenos/metabolismo , ADN/metabolismo , Epidermis/metabolismo , ARN/metabolismo , Animales , Frío , Femenino , Masculino , Ratones , Espectrometría de Fluorescencia
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