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BACKGROUND: Chemotherapy-induced premature ovarian insufficiency (POI) impacts fertility and other aspects of women's health. The OPTION trial tested whether administration of a gonadotropin-releasing hormone agonist during chemotherapy for early breast cancer reduced the risk of POI. PATIENTS AND METHODS: This was a prospective, randomized, parallel group study of the gonadotropin-releasing hormone agonist goserelin administered before and during chemotherapy for breast cancer with stage I-IIIB disease. The primary outcome was amenorrhoea between 12 and 24 months after randomization, supported by elevated follicle stimulating hormone concentrations to give an additional analysis as rate of POI. RESULTS: A total of 227 patients were randomized and the primary analysis was conducted on 202 patients. Goserelin reduced the prevalence of amenorrhoea between 12 and 24 months to 22% versus 38% in the control group (P = 0.015) and the prevalence of POI to 18.5% versus 34.8% in the control group (P = 0.048). Follicle stimulating hormone concentrations were also lower in all women treated with goserelin at both 12 and 24 months (P = 0.027, P = 0.001, respectively). The effect of goserelin was not statistically significant in women >40 years. Assessment of the ovarian reserve using anti-Müllerian hormone showed a marked fall in both groups during treatment to median values of 5% of pretreatment levels in the control group and 7% in the goserelin group, which were not significantly different between groups. CONCLUSION: This study shows that goserelin reduced the risk of POI in women treated with chemotherapy for early breast cancer, with particular efficacy in women aged ≤40 years old. The degree of ovarian protection also seems limited and the clinical significance for fertility and longer term prevention of estrogen deficiency-related outcomes needs to be determined.
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Amenorrea/prevención & control , Antineoplásicos Hormonales/uso terapéutico , Antineoplásicos/efectos adversos , Neoplasias de la Mama/tratamiento farmacológico , Hormona Liberadora de Gonadotropina/agonistas , Goserelina/uso terapéutico , Insuficiencia Ovárica Primaria/prevención & control , Adulto , Amenorrea/inducido químicamente , Antineoplásicos/uso terapéutico , Antineoplásicos Hormonales/administración & dosificación , Diagnóstico Precoz , Femenino , Goserelina/administración & dosificación , Humanos , Insuficiencia Ovárica Primaria/inducido químicamente , Estudios ProspectivosRESUMEN
Our acceptance of exposure to radiation is somewhat schizophrenic. We accept that the use of high doses of radiation is still one of the most valuable weapons in our fight against cancer, and believe that bathing in radioactive spas is beneficial. On the other hand, as a species, we are fearful of exposure to man-made radiation as a result of accidents related to power generation, even though we understand that the doses are orders of magnitude lower than those we use everyday in medicine. The 70th anniversary of the detonation of the atomic bombs in Hiroshima and Nagasaki was marked in 2015. The 30th anniversary of the Chernobyl nuclear power plant accident will be marked in April 2016. March 2016 also sees the fifth anniversary of the accident at the Fukushima nuclear power plant. Perhaps now is an opportune time to assess whether we are right to be fearful of the effects of low doses of radiation, or whether actions taken because of our fear of radiation actually cause a greater detriment to health than the direct effect of radiation exposure.
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Efectos de la Radiación , Exposición a la Radiación , Factores de Edad , Radiación de Fondo , Accidente Nuclear de Chernóbil , Relación Dosis-Respuesta en la Radiación , Accidente Nuclear de Fukushima , Humanos , Neoplasias Inducidas por Radiación/etiología , Guerra Nuclear , Dosis de Radiación , Exposición a la Radiación/efectos adversos , Liberación de Radiactividad Peligrosa , Radioterapia , Medición de RiesgoRESUMEN
The eye is an important sense organ for teleost species but can vary greatly depending on the adaption to the habitat, environment during ontogeny and developmental stage of the fish. The eye and retinal morphology of eight commonly caught trawl bycatch species were described: Lepidotrigla mulhalli; Lophonectes gallus; Platycephalus bassensis; Sillago flindersi; Neoplatycephalus richardsoni; Thamnaconus degeni; Parequula melbournensis; and Trachurus declivis. The cone densities ranged from 38 cones per 0.01 mm(2) for S. flindersi to 235 cones per 0.01 mm(2) for P. melbournensis. The rod densities ranged from 22800 cells per 0.01 mm(2) for L. mulhalli to 76634 cells per 0.01 mm(2) for T. declivis and potential visual acuity (based on anatomical measures) ranged from 0.08 in L. gallus to 0.31 in P. melbournensis. Higher rod densities were correlated with maximum habitat depths. Six species had the regular pattern of four double cones arranged around a single cone in the photoreceptor mosaic, while T. declivis had only rows of double cones. P. melbournensis had the greatest potential ability for detecting fine detail based on eye anatomy. The potential visual acuity estimates and rod densities can be applied to suggest the relative detection ability of different species in a commercial fishing context, since vision is a critical sense in an illuminated environment for perceiving an oncoming trawl.
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Peces/fisiología , Células Fotorreceptoras Retinianas Conos/citología , Células Fotorreceptoras Retinianas Bastones/citología , Agudeza Visual/fisiología , Análisis de Varianza , Animales , Recuento de Células , Ojo/anatomía & histología , Cristalino/anatomía & histología , Visión OcularRESUMEN
The failure of food security and livelihood interventions to adapt to conflict settings remains a key challenge in humanitarian responses to protracted crises. This paper proposes a social capital analysis to address this policy gap, adding a political economy dimension on food security and conflict to the actor-based livelihood framework. A case study of three hillsides in north Burundi provides an ethnographic basis for this hypothesis. While relying on a theoretical framework in which different combinations of social capital (bonding, bridging, and linking) account for a diverse range of outcomes, the findings offer empirical insights into how social capital portfolios adapt to a protracted crisis. It is argued that these social capital adaptations have the effect of changing livelihood policies, institutions, and processes (PIPs), and clarify the impact of the distribution of power and powerlessness on food security issues. In addition, they represent a solid way of integrating political economy concerns into the livelihood framework.
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Urgencias Médicas , Abastecimiento de Alimentos , Sistemas de Socorro/organización & administración , Apoyo Social , Altruismo , Burundi , Humanos , Política , Poder PsicológicoRESUMEN
The only unequivocal radiological effect of the Chernobyl accident on human health is the increase in thyroid cancer in those exposed in childhood or early adolescence. Cancer is a complicated disease and it is unclear whether the mechanism by which radiation gives rise to cancer differs from that involved in the generation of cancers of the same type by other environmental stimuli. The Chernobyl Tissue Bank was established in response to the scientific interest in studying the molecular biology of thyroid cancer after Chernobyl to address this question. The project is supported by the governments of Ukraine and Russia, and financially supported (in total around US$3 million) by the European Commission, the National Cancer Institute of the USA and the Sasakawa Memorial Health Foundation of Japan. The project began collecting a variety of biological samples from patients on 1 October 1988, and has supplied material to 23 research projects in Japan, the USA and Europe. The establishment of the Chernobyl Tissue Bank has facilitated co-operation between these research projects and the combination of clinical and research data provides a paradigm for cancer research in the molecular biological age.
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Investigación Biomédica/organización & administración , Accidente Nuclear de Chernóbil , Neoplasias Inducidas por Radiación/patología , Neoplasias de la Tiroides/patología , Bancos de Tejidos/organización & administración , Humanos , UcraniaRESUMEN
BACKGROUND/OBJECTIVES: Hyperglycaemia is associated with increased platelet aggregation that increases the risk of thrombosis in people with type-2 diabetes and cardiovascular disease. Low glycemic index (GI) meals high in carbohydrate or moderately high in protein have been shown to acutely reduce postprandial excursions of plasma glucose and insulin compared with high carbohydrate high GI meals. However, it is not known whether these differences in glucose and insulin profile also impact on postprandial platelet aggregation. This study aimed to investigate the acute effects of three iso-energetic meals, on measures of postprandial platelet aggregation, in healthy individuals. SUBJECTS/METHODS: A randomised cross-over study compared the acute effects of a high GI high carbohydrate (HGI-HC), a low GI high carbohydrate (LGI-HC) and a low GI moderately high in protein and fat (LGI-MPF) meal on postprandial platelet aggregation, glucose, insulin and triglyceride concentrations. Comparisons were made at fasting, 60 and 120 min postprandially. RESULTS: A total of 32 volunteers (mean ± s.d.; age 59.9 ± 11.7 years, BMI 27.1 ± 3.7 kg/m(2)) participated in the study. Results showed significant reductions in maximum platelet aggregation postprandially with nonsignificant differences (all P > 0.29) between the three meals. Glucose and insulin were significantly (both P < 0.001) higher at 60 min postprandially on the HGI-HC meal compared with both LGI-HC and LGI-MPF meals. Triglycerides were not significantly different (all P > 0.25) between the three test meals. CONCLUSION: In healthy individuals platelet aggregation is reduced postprandially but this decrease is similar between meals of different GI that induce different glucose and insulin responses.
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Glucemia/metabolismo , Dieta , Carbohidratos de la Dieta/farmacología , Índice Glucémico , Hiperglucemia/fisiopatología , Insulina/sangre , Agregación Plaquetaria/efectos de los fármacos , Anciano , Enfermedades Cardiovasculares/sangre , Enfermedades Cardiovasculares/complicaciones , Estudios Cruzados , Complicaciones de la Diabetes/sangre , Carbohidratos de la Dieta/metabolismo , Grasas de la Dieta/farmacología , Proteínas en la Dieta/farmacología , Ingestión de Energía , Femenino , Humanos , Hiperglucemia/sangre , Hiperglucemia/complicaciones , Masculino , Persona de Mediana Edad , Agregación Plaquetaria/fisiología , Periodo Posprandial , Valores de Referencia , Trombosis/sangre , Trombosis/etiología , Triglicéridos/sangreAsunto(s)
Accidente Nuclear de Chernóbil , Neoplasias Inducidas por Radiación/epidemiología , Ceniza Radiactiva/efectos adversos , Neoplasias de la Tiroides/epidemiología , Niño , Relación Dosis-Respuesta en la Radiación , Humanos , Radioisótopos de Yodo/envenenamiento , Neoplasias Inducidas por Radiación/etiología , Neoplasias de la Tiroides/etiología , Ucrania/epidemiologíaRESUMEN
The Chernobyl accident was followed by a large increase in the incidence of thyroid carcinoma in the areas exposed to high levels of fallout. The Chernobyl Tumor Bank was set up in 1998 to make tumours available for study internationally, and a pathology panel reviewed all the tumours and established an agreed diagnosis. The thyroid tumours that were discovered after the Chernobyl nuclear accident were virtually all (95%) of the papillary carcinoma type. Rare examples of other tumour types were identified. Within the papillary group, several subtypes were noted, including classical or usual type, follicular variant, solid variant and mixed patterns Diffuse sclerosis variant, cribriform/morular type and Warthin-like variant were rare. No tall cell or columnar cell variants were identified. The tumours examined by the Pathology Panel of the Chernobyl Tumor Bank constitute a large representative sample (estimated at about 50%) of the tumours that developed in this population. This overview describes the method adopted by the panel and the different diagnostic categories adopted; illustrates the pathology of these neoplasms; compares the pathological characteristics of the early lesions with those identified after long latency periods and the institution of screening programmes and outlines the possible associated causes for the various morphological patterns seen.
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Carcinoma Papilar/epidemiología , Carcinoma Papilar/patología , Accidente Nuclear de Chernóbil , Neoplasias de la Tiroides/epidemiología , Neoplasias de la Tiroides/patología , Adolescente , Adulto , Niño , Femenino , Humanos , Masculino , Ucrania/epidemiología , Adulto JovenRESUMEN
The only unequivocal radiological effect of the Chernobyl accident on human health is the increase in thyroid cancer in those exposed in childhood or early adolescence. In response to the scientific interest in studying the molecular biology of thyroid cancer after Chernobyl, the Chernobyl Tissue Bank was established. The project is supported by the governments of Ukraine and Russia, and financially supported (in total around US$3 million) by the European Commission, the National Cancer Institute of the USA and the Sasakawa Memorial Health Foundation of Japan. The project began collecting a variety of biological samples from patients on 1 October 1988, and has supplied material to 21 research projects in Japan, the USA and Europe. The establishment of the Chernobyl Tissue Bank has facilitated co-operation between these research projects and the combination of clinical and research data provides a paradigm for cancer research in the molecular biological age.
Asunto(s)
Accidente Nuclear de Chernóbil , Neoplasias Inducidas por Radiación/patología , Neoplasias de la Tiroides/patología , Bancos de Tejidos , Recolección de Datos , Femenino , Humanos , Masculino , Neoplasias Inducidas por Radiación/sangre , Neoplasias Inducidas por Radiación/etiología , Liberación de Radiactividad Peligrosa , Neoplasias de la Tiroides/sangre , Neoplasias de la Tiroides/etiología , UcraniaRESUMEN
INTRODUCTION: Benefits of immunosuppressive therapy in Crohn's disease have been demonstrated in controlled trials; however, it is unclear whether these drugs alter the longer-term natural history of this condition. AIMS AND METHODS: To assess changes in disease outcomes in a population-based cohort of patients diagnosed in Cardiff from 1986 to 2003. Case notes from Crohn's disease incidence studies in Cardiff were reviewed retrospectively for disease characteristics and follow-up information on drug therapy, and the need for surgery for Crohn's disease. The study population was divided into three groups by year of diagnosis (Group A=1986-1991, Group B=1992-1997 and Group C=1998-2003). RESULTS: 341 patients were included. Kaplan-Meier (KM) analysis showed increasing use of immunosuppressants over time. At 5 years after diagnosis this was 11% in Group A, 28% in Group B, and 45% in Group C (p=0.001) and the median time to start of thiopurines was 77, 21 and 11 months in Group A, B and C respectively. There was a significant reduction in long-term steroid use at 5 years post diagnosis: 45 (44%), 31 (31%) and 24 (19%) patients in Group A, B and C respectively (p=0.001). KM analysis showed a significant reduction in the cumulative probability of intestinal surgery: At 5 years this was 59% (Group A), 37% (Group B) and 25% (Group C) (p=0.001). In a multivariate Cox analysis, year of diagnosis, disease location, oral corticosteroids within 3 months of diagnosis and early thiopurine use (within the first year of diagnosis) were all independent factors affecting likelihood of intestinal surgery. CONCLUSION: This population-based cohort shows marked changes in rates of surgery, and the reduction is independently associated with year of diagnosis, and associated temporally with increased and earlier thiopurine use.
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Enfermedad de Crohn/tratamiento farmacológico , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Azatioprina/uso terapéutico , Niño , Preescolar , Enfermedad de Crohn/epidemiología , Enfermedad de Crohn/cirugía , Procedimientos Quirúrgicos del Sistema Digestivo/estadística & datos numéricos , Procedimientos Quirúrgicos del Sistema Digestivo/tendencias , Esquema de Medicación , Métodos Epidemiológicos , Femenino , Glucocorticoides/administración & dosificación , Glucocorticoides/uso terapéutico , Humanos , Inmunosupresores/efectos adversos , Inmunosupresores/uso terapéutico , Masculino , Mercaptopurina/uso terapéutico , Persona de Mediana Edad , Neoplasias/epidemiología , Neoplasias/etiología , Gales/epidemiología , Adulto JovenRESUMEN
Breast cancer incidence increases with age, but there are important age-related differences with respect to the frequency of different tumour subtypes with respect to hormone receptor status and pathological grade. In general, younger patients show a higher frequency of oestrogen receptor-negative, higher-grade tumours, whereas in older patients there is a higher frequency of oestrogen receptor-positive, low-grade tumours. This accounts for the fact that, in general, elderly patients are thought to have a less aggressive form of the disease. However, this does not mean that all elderly patients with breast cancer necessarily have a good prognosis. An increased understanding of the mechanisms of tissue ageing and how these affect the molecular biological phenotype of breast cancers in cohorts of different ages will aid the oncologist's confidence in tailoring treatment more appropriately to the likely prognosis, and the development of novel, hopefully less toxic, treatments for specific subtypes of breast cancer in the elderly population.
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Envejecimiento/fisiología , Neoplasias de la Mama/patología , Anciano , Neoplasias de la Mama/clasificación , Femenino , Humanos , InmunofenotipificaciónRESUMEN
OBJECTIVES: Alginate materials are considered unsuitable for precise fixed prosthetic rehabilitation due to their tendency to undergo spontaneous syneresis. Commercial alginate impression materials were investigated using Nuclear Magnetic Resonance (NMR) Spectroscopy to probe the relation between changes in the microscopic water environment and dimensional change to obtain a better understanding of spontaneous syneresis. METHODS: NMR was used to measure the spin-lattice relaxation times (T(1)) of (1)H nuclei in water in alginate matrices to characterize changes in gel structure over time. These results were related to the dimensional stabilities of the alginate impression materials, their chemical compositions, and the Moisture Sorption Isotherms (MSI) obtained by incubation at fixed relative humidities. RESULTS: The rate of change of T(1) with time was found to be a better predictor of dimensional stability than MSI. The greatest dimensional stability for the alginate powders investigated was associated with a high filler:alginate ratio and a high Ca:Na ratio. SIGNIFICANCE: Nuclear magnetic resonance spectroscopy may used to measure changes in alginate impression materials under conditions where no dimensional change can be observed directly. Changes occurred rapidly even at 100% humidity, suggesting the dimensional stability of alginate impression materials is partially independent of the rate of dehydration. The results may open a way to formulate alginate impression materials more suitable for precise fabrication of dental prostheses.
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Alginatos/química , Materiales de Impresión Dental/química , Absorción , Calcio/análisis , Geles/química , Humedad , Concentración de Iones de Hidrógeno , Espectroscopía de Resonancia Magnética , Sodio/análisis , Factores de Tiempo , Agua/análisisRESUMEN
BACKGROUND: Smoking has a detrimental effect in Crohn's disease (CD), but this may be due to factors in smoking other than nicotine. Given that transdermal nicotine benefits ulcerative colitis (UC), and there is a considerable overlap in the treatment of UC and CD, the possible beneficial effect of nicotine has been examined in patients with Crohn's colitis. AIMS: To assess the efficacy and safety of nicotine enemas in active Crohn's colitis. Patients. Thirteen patients with active rectosigmoid CD; 3 patients were excluded because they received antibiotics. METHODS: Subjects were given 6 mg nicotine enemas, each day for 4 weeks, in an open pilot study. At the beginning and end of the trial, a Crohn's disease activity index (CDAI) score was calculated, sigmoidoscopy was performed, and haematological inflammatory markers measured. RESULTS: Mean CDAI decreased from 202 to 153-the score was reduced in 6 patients, unchanged in 3, and increased in one. Frequency of bowel movements decreased in 8 patients and the sigmoidoscopy grade was reduced in 7. Mean C-reactive protein decreased from 22.0 to 12.3 mg/L. There were no withdrawals due to adverse events. CONCLUSIONS: In this relatively small study of patients with active Crohn's colitis, 6 mg nicotine enemas appeared to be of clinical benefit in most patients. They were well tolerated and safe.
RESUMEN
BACKGROUND: The incidence of Crohn's disease rose rapidly in industralized countries over the past 50 years, but it is unclear whether the incidence is still rising or has reached a plateau. AIMS: To update the long-term incidence study of Crohn's disease in Cardiff for 1996-2005, to investigate whether incidence is still rising and to study changes in disease characteristics over time. METHOD: Crohn's cases identified by retrospective analysis of hospital records as in previous studies in Cardiff. RESULTS: Two hundred and twelve cases were identified. Corrected incidence for this decade was 66 x 10(6) per year (95% confidence interval: 58-76), showing a continuing rise compared to previous decades. The proportion with colonic disease at presentation continues to rise (43%) with a corresponding fall in those with terminal ileal disease. There remains a strong female preponderance (F:M 1.6:1) as in previous studies. The incidence in children under age 16 continues to rise, and the median age at diagnosis has fallen slightly. CONCLUSION: Crohn's disease incidence continues to rise slowly in Cardiff with a continuing increase in those presenting with colonic disease, which is now the commonest disease pattern.
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Colitis/epidemiología , Enfermedad de Crohn/epidemiología , Ileítis/epidemiología , Adolescente , Adulto , Distribución por Edad , Edad de Inicio , Anciano , Anciano de 80 o más Años , Niño , Intervalos de Confianza , Femenino , Estudios de Seguimiento , Humanos , Incidencia , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Distribución por Sexo , Fumar , Estadísticas no Paramétricas , Gales/epidemiologíaRESUMEN
BACKGROUND: Smoking increases plasma fibrinogen and cardiovascular risk whereas transdermal nicotine may not. Fibrinogen is an acute phase protein and may reflect disease activity in ulcerative colitis. AIMS: To examine the effect of topical nicotine on plasma fibrinogen and any relationship between fibrinogen and ulcerative colitis disease activity. PATIENTS: Forty-eight non-smokers with moderately active ulcerative colitis. METHODS: Patients were randomised to 6 mg nicotine enema or placebo for 6 weeks, followed by open nicotine therapy for 4 weeks. Plasma fibrinogen was measured at baseline and after 6 and 10 weeks; at each assessment sigmoidoscopy with a rectal biopsy was performed. RESULTS.: At 6 weeks median plasma fibrinogen was 3.30 g/l on nicotine compared to 3.05 g/l on placebo, P = 0.90 when adjusted for baseline values. There was a correlation between fibrinogen and the UC disease activity index (UCDAI) at weeks 0 and 10, P = 0.036 and 0.033, respectively, and between fibrinogen and sigmoidoscopic grade at each assessment, P = 0.014, 0.021 and 0.034. Changes in fibrinogen did not correlate with changes in disease severity. CONCLUSIONS: There was no significant effect of nicotine enemas, in either direction, on plasma fibrinogen-this was raised in moderately active UC and correlated with the sigmoidoscopic grade of colitis and the UCDAI; however, fibrinogen was not sufficiently sensitive to be of practical clinical value.
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Colitis Ulcerosa/sangre , Fibrinógeno/análisis , Nicotina/farmacología , Agonistas Nicotínicos/farmacología , Enema , Femenino , Humanos , Masculino , Persona de Mediana Edad , Nicotina/administración & dosificación , Agonistas Nicotínicos/administración & dosificación , Sensibilidad y Especificidad , SigmoidoscopíaRESUMEN
BACKGROUND: Therapeutic enemas are often used to treat active colitis but their retention may be limited because of urgency to defecate. Some preparations may be better retained and tolerated than others because of their physical properties. AIM: To compare patient preference and retention of four therapeutic enemas, including a nicotine enema, in patients with ulcerative colitis (UC). METHODS: Twenty four patients with active UC received the four trial enemas-corticosteroid, 5-amino salicylate (5-ASA), and nicotine liquid enemas and a corticosteroid foam, in a randomised order, taking one enema on each of four successive nights. Patients scored them 1 to 4 for ease of administration and retention, degree of abdominal bloating, and for their overall preference. RESULTS: Fifteen patients rated nicotine their overall favourite or second favourite, compared with 14 for corticosteroid foam and 11 for 5-ASA and corticosteroid liquids, but this was not significant (p = 0.302). Overall, there was no significant difference in overnight retention. However, the nicotine enema tended to be less well retained in patients with milder urgency but a higher proportion retained it overnight with more severe urgency (p = 0.031 compared with 5-ASA enema). CONCLUSION: There was no significant difference in patient preference or overall duration of retention for the four enemas.
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Colitis Ulcerosa/terapia , Enema/métodos , Fármacos Gastrointestinales/uso terapéutico , Satisfacción del Paciente , Corticoesteroides/uso terapéutico , Adulto , Anciano , Anciano de 80 o más Años , Enema/psicología , Enema/normas , Femenino , Humanos , Masculino , Persona de Mediana Edad , Nicotina/uso terapéuticoRESUMEN
Metallothionein (MT) crypt-restricted immunopositivity indices (MTCRII) are colonic crypt stem cell mutation markers that may be induced early and in abundance after mutagen treatment. Metallothionein is the endogenous reporter gene for MTCRII, but is not typically implicated in the classical pathway of colorectal tumorigenesis. Hence, the oncological relevance of MTCRII is unclear. This study tests the hypothesis that MTCRII induced by N-methyl-N-nitrosourea (MNU) and lambda carrageenan (lambdaCgN) associate with aberrant crypt foci (ACF) in mouse colon. Undegraded lambdaCgN and MNU were tested alone and in combination against MTCRII and ACF in Balb/c mice, at 20 weeks after the start of treatment. MTCRII were unaffected by lambdaCgN alone. Combined lambdaCgN/MNU treatments induced greater MTCRII (P < 0.01) as well as greater number (P < 0.001) and crypt multiplicity (P < 0.01) of ACF than MNU alone. MTCRII were approximately 10-fold more numerous than ACF, although linear correlations were observed between these parameters (r = 0.732; P < 0.01). MTCRII are induced by lambdaCgN/MNU interactions in sufficient numbers to provide statistical power from relatively small sample sizes and correlate with ACF formation. MTCRII could thus provide the basis for a novel medium-term murine bioassay relevant to early-stage colorectal tumorigenesis.
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Biomarcadores de Tumor/genética , Colon/patología , Neoplasias del Colon/genética , Neoplasias del Colon/patología , Mucosa Intestinal/patología , Metalotioneína/genética , Animales , Transformación Celular Neoplásica/genética , Transformación Celular Neoplásica/patología , Femenino , Ratones , Ratones Endogámicos BALB C , Mutágenos/efectos adversos , Mutación , Células Madre/fisiologíaRESUMEN
In both medullary carcinoma and papillary carcinoma of the thyroid, altered expression of the RET gene is implicated in tumorigenesis. Recent studies suggest that loss of heterozygosity (LOH) at the G691S SNP may be associated with tumors from patients with a history of radiation exposure. We investigated LOH for three RET SNPs (G691S, S904S, and L769L) in tumor and normal tissue from 46 patients from Ukraine and Belarus who were exposed to radioactive fallout following the Chernobyl nuclear accident and were operated for papillary thyroid carcinoma between 1995 and 2000. Normal tissue from 28 patients was heterozygous for at least one SNP; DNA from the corresponding tumor samples was also heterozygous, indicating that no LOH had taken place. To assess SNP frequencies in a radiation-associated thyroid cancer cohort, we investigated a further 68 unpaired post-Chernobyl samples. For G691S, there was considerable deviation from Hardy-Weinberg equilibrium; more detailed analysis showed that this was linked to age at onset of disease. Among younger patients, the distribution of genotypes conformed to Hardy-Weinberg equilibrium; among older patients, we observed marked deviation (p = 0.0072), with significant over-representation of the rare S allele relative to the younger groups (Fisher's exact, p = 0.0233). This suggests that SNPs in the RET oncogene may play a role in sporadic papillary thyroid carcinoma.