Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 15 de 15
Filtrar
1.
Methods Mol Biol ; 1180: 337-52, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-25015158

RESUMEN

Optimal processing, handling, and sampling of prostatic biopsies, transurethral resections, and radical prostatectomy specimens ensure accurate diagnosis and staging. Prognostic factors derived from careful examination of tissue samples are critical for patient management, including cancer volume, extraprostatic extension, surgical margins, vascular/lymphatic invasion, and perineural invasion. This chapter addresses these important issues, including recent recommendations of a consensus panel of the International Society of Urologic Pathologists.


Asunto(s)
Biopsia/métodos , Próstata/patología , Neoplasias de la Próstata/diagnóstico , Neoplasias de la Próstata/patología , Biopsia con Aguja Gruesa , Humanos , Masculino , Pronóstico , Neoplasias de la Próstata/cirugía , Resección Transuretral de la Próstata
2.
Biofactors ; 39(5): 575-88, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23625367

RESUMEN

The anti-cancer activity of organic selenium has been most consistently documented at supra-nutritional levels at which selenium-dependent, antioxidant enzymes are maximized in both expression and activity. Thus, there is a strong imperative to identify mechanisms other than antioxidant protection to account for selenium's anti-cancer activity. In vivo work in dogs showed that dietary selenium supplementation decreased DNA damage but increased apoptosis in the prostate, leading to a new hypothesis: Organic selenium exerts its cancer preventive effect by selectively increasing apoptosis in DNA-damaged cells. Here, we test whether organic selenium (methylseleninic acid; MSA) triggers more apoptosis in human and canine prostate cancer cells that have more DNA damage (strand breaks) created by hydrogen-peroxide (H2O2) at noncytotoxic doses prior to MSA exposure. Apoptosis triggered by MSA was significantly higher in H2O2-damaged cells. A supra-additive effect was observed--the extent of MSA-triggered apoptosis in H2O2-damaged cells exceeded the sum of apoptosis induced by MSA or H2O2 alone. However, neither the persistence of H2O2-induced DNA damage, nor the activation of mitogen-activated protein kinases was required to sensitize cells to MSA-triggered apoptosis. Our results document that selenium can exert a "homeostatic housecleaning" effect--a preferential elimination of DNA-damaged cells. This work introduces a new and potentially important perspective on the anti-cancer action of selenium in the aging prostate that is independent of its role in antioxidant protection.


Asunto(s)
Anticarcinógenos/farmacología , Apoptosis/efectos de los fármacos , Homeostasis/efectos de los fármacos , Compuestos de Organoselenio/farmacología , Animales , Línea Celular Tumoral , Proliferación Celular , Daño del ADN , Reparación del ADN/efectos de los fármacos , Perros , Etopósido/farmacología , Humanos , Peróxido de Hidrógeno/farmacología , Masculino , Mutágenos/farmacología , Oxidantes/farmacología , Neoplasias de la Próstata , Cinostatina/farmacología
3.
Nutrients ; 4(11): 1650-63, 2012 Nov 06.
Artículo en Inglés | MEDLINE | ID: mdl-23201838

RESUMEN

Prostate cancer is the product of dysregulated homeostasis within the aging prostate. Supplementation with selenium in the form of selenized yeast (Se-yeast) significantly reduced prostate cancer incidence in the Nutritional Prevention of Cancer Trial. Conversely, the Selenium and Vitamin E Cancer Prevention Trial (SELECT) showed no such cancer-protective advantage using selenomethionine (SeMet). The possibility that SeMet and Se-yeast are not equipotent in promoting homeostasis and cancer risk reduction in the aging prostate has not been adequately investigated; no direct comparison has ever been reported in man or animals. Here, we analyzed data on prostatic responses to SeMet or Se-yeast from a controlled feeding trial of 49 elderly beagle dogs-the only non-human species to frequently develop prostate cancer during aging-randomized to one of five groups: control; low-dose SeMet, low-dose Se-yeast (3 µg/kg); high-dose SeMet, high-dose Se-yeast (6 µg/kg). After seven months of supplementation, we found no significant selenium form-dependent differences in toenail or intraprostatic selenium concentration. Next, we determined whether SeMet or Se-yeast acts with different potency on six markers of prostatic homeostasis that likely contribute to prostate cancer risk reduction-intraprostatic dihydrotestosterone (DHT), testosterone (T), DHT:T, and epithelial cell DNA damage, proliferation, and apoptosis. By analyzing dogs supplemented with SeMet or Se-yeast that achieved equivalent intraprostatic selenium concentration after supplementation, we showed no significant differences in potency of either selenium form on any of the six parameters over three different ranges of target tissue selenium concentration. Our findings, which represent the first direct comparison of SeMet and Se-yeast on a suite of readouts in the aging prostate that reflect flux through multiple gene networks, do not further support the notion that the null results of SELECT are attributable to differences in prostatic consequences achievable through daily supplementation with SeMet, rather than Se-yeast.


Asunto(s)
Próstata , Selenio/administración & dosificación , Selenometionina/administración & dosificación , Levaduras , Envejecimiento , Animales , Apoptosis/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Daño del ADN/efectos de los fármacos , Suplementos Dietéticos , Dihidrotestosterona/análisis , Perros , Homeostasis , Masculino , Modelos Animales , Próstata/química , Próstata/patología , Neoplasias de la Próstata/patología , Neoplasias de la Próstata/prevención & control , Selenio/análisis , Selenometionina/análisis , Testosterona/análisis
4.
J Nutr ; 139(10): 1908-13, 2009 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-19710157

RESUMEN

Soy isoflavones and their metabolites, with estrogenic activity, have been considered candidates for reducing postmenopausal bone loss. In this study, we examined the effect of dietary equol, a bioactive metabolite of the soy isoflavone daidzein, on equol tissue distribution, bone parameters, and reproductive tissue activity using an adult ovariectomized (OVX) rat model. An 8-wk feeding study was conducted to compare 4 dietary treatments of equol (0, 50, 100, 200 mg/kg diet) in 6-mo-old OVX female Sprague-Dawley rats. A dose response increase in tissue equol concentrations was observed for serum, liver, kidney, and heart, and a plateau occurred at 100 mg equol/kg diet for intestine. In OVX rats receiving 200 mg equol/kg diet, femoral calcium concentration was greater than those receiving lower doses but was still less than SHAM (P < 0.05), and other bone measures were not improved. Tibia calcium concentrations were lower in OVX rats receiving 100 and 200 mg equol/kg diet compared with the OVX control rats. Trabecular bone mineral density of tibia was also lower in equol-fed OVX rats. At this dietary equol intake, uterine weight was higher (P < 0.05) than in other OVX groups but lower than the SHAM-operated intact rats. The 200 mg/kg diet dose of dietary equol significantly increased proliferative index in the uterine epithelium. Dietary equol had no stimulatory effect on mammary gland epithelium. We conclude that in OVX rats, a dietary equol dose that had modest effect on bone also exerts mild uterotropic effects.


Asunto(s)
Densidad Ósea/efectos de los fármacos , Suplementos Dietéticos , Isoflavonas/farmacología , Fitoestrógenos/farmacología , Útero/efectos de los fármacos , Animales , Huesos/química , Calcio/análisis , Equol , Femenino , Dosificación Letal Mediana , Tamaño de los Órganos , Ovariectomía , Ratas , Ratas Sprague-Dawley , Útero/anatomía & histología
5.
Dose Response ; 8(3): 285-300, 2009 Dec 21.
Artículo en Inglés | MEDLINE | ID: mdl-20877485

RESUMEN

Our work in dogs has revealed a U-shaped dose response between selenium status and prostatic DNA damage that remarkably parallels the relationship between dietary selenium and prostate cancer risk in men, suggesting that more selenium is not necessarily better. Herein, we extend this canine work to show that the selenium dose that minimizes prostatic DNA damage also maximizes apoptosis-a cancer-suppressing death switch used by prostatic epithelial cells. These provocative findings suggest a new line of thinking about how selenium can reduce cancer risk. Mid-range selenium status (.67-.92 ppm in toenails) favors a process we call "homeostatic housecleaning"-an upregulated apoptosis that preferentially purges damaged prostatic cells. Also, the U-shaped relationship provides valuable insight into stratifying individuals as selenium-responsive or selenium-refractory, based upon the likelihood of reducing their cancer risk by additional selenium. By studying elderly dogs, the only non-human animal model of spontaneous prostate cancer, we have established a robust experimental approach bridging the gap between laboratory and human studies that can help to define the optimal doses of cancer preventives for large-scale human trials. Moreover, our observations bring much needed clarity to the null results of the Selenium and Vitamin E Cancer Prevention Trial (SELECT) and set a new research priority: testing whether men with low, suboptimal selenium levels less than 0.8 ppm in toenails can achieve cancer risk reduction through daily supplementation.

6.
Nutr Cancer ; 60(1): 1-6, 2008.
Artículo en Inglés | MEDLINE | ID: mdl-18444129

RESUMEN

Now, more than ever, there is great need for personalized cancer prevention. We define personalized cancer prevention as a strategy that will enable each person to reduce his or her risk for lethal cancer by matching the dose, duration, and timing of an intervention with their own cancer risk profile. Most research studies provide us with data on the average person. But who is the average person anyway? The central tenet of personalized cancer prevention is that average is overrated. In this article, we frame what are the major obstacles to developing personalized cancer-reducing interventions: the lack of validated, non-invasive stratifiers of risk; the U-shaped dose response between cancer-fighting nutrients (e.g., selenium) and DNA damage, meaning that more of a good thing is not necessarily a good thing; the relatively brief duration of interventions evaluated in human prevention trials; the challenge of finding populations in which the impact of early life interventions on the incidence of cancers affecting older adults can be studied; and the interindividual differences in gene expression that may influence a person's response to a particular nutrient. Moreover, we contend that those who study personalized cancer prevention will need a unique constellation of expertise, including an understanding of cancer and aging, a passion for prevention, and proven health communication skills. We propose that becoming cross-trained in cancer and aging and taking more responsibility for communicating health-related research to the public in the proper context are two of the most important ways scientists can move us all closer to the goal of personalized cancer prevention. Every fisherman knows that where he casts his net determines his catch. Now, we ask: When it comes to solving the cancer problem, where should we be casting our nets?


Asunto(s)
Suplementos Dietéticos/efectos adversos , Neoplasias/prevención & control , Vitaminas/efectos adversos , Envejecimiento/fisiología , Antioxidantes/efectos adversos , Relación Dosis-Respuesta a Droga , Humanos , Neoplasias/mortalidad , Necesidades Nutricionales , Ensayos Clínicos Controlados Aleatorios como Asunto , Medición de Riesgo , Vitaminas/uso terapéutico
7.
Arch Pathol Lab Med ; 131(3): 360-71, 2007 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-17516739

RESUMEN

CONTEXT: Prostate cancer is the most common cancer of men in the United States and is third only to lung and colon cancer as a cause of cancer death. In 2006, 27,350 Americans will die of prostate cancer, and 234,460 new cases will be diagnosed. Treatment changes in the benign and cancerous prostate create diagnostic challenges in pathologic interpretation, particularly in needle biopsy specimens and in evaluation of extraprostatic metastases. OBJECTIVE: To summarize therapy-related pathologic findings in the prostate with emphasis on recognition of treated adenocarcinoma. DATA SOURCES: Extensive review of published literature and the authors' experience. CONCLUSIONS: Following therapy for prostate cancer, it is critical that the clinician provide the pertinent history of androgen deprivation or radiation therapy to assist the pathologist in rendering the correct diagnosis.


Asunto(s)
Adenocarcinoma/patología , Adenocarcinoma/terapia , Próstata/patología , Neoplasias de la Próstata/patología , Neoplasias de la Próstata/terapia , Inhibidores de 5-alfa-Reductasa , Antagonistas de Andrógenos/uso terapéutico , Criocirugía , Diagnóstico Diferencial , Humanos , Hipertermia Inducida , Masculino , Antígeno Prostático Específico , Prostatectomía , Neoplasia Intraepitelial Prostática/patología , Neoplasia Intraepitelial Prostática/terapia , Radioterapia
8.
Carcinogenesis ; 26(7): 1256-62, 2005 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-15817614

RESUMEN

Daily supplementation with the essential trace mineral selenium significantly reduced prostate cancer risk in men in the Nutritional Prevention of Cancer Trial. However, the optimal intake of selenium for prostate cancer prevention is unknown. We hypothesized that selenium significantly regulates the extent of genotoxic damage within the aging prostate and that the relationship between dietary selenium intake and DNA damage is non-linear, i.e. more selenium is not necessarily better. To test this hypothesis, we conducted a randomized feeding trial in which 49 elderly beagle dogs (physiologically equivalent to 62-69-year-old men) received nutritionally adequate or supranutritional levels of selenium for 7 months, in order to mimic the range of dietary selenium intake of men in the United States. Our results demonstrate an intriguing U-shaped dose-response relationship between selenium status (toenail selenium concentration) and the extent of DNA damage (alkaline Comet assay) within the prostate. Further, we demonstrate that the concentration of selenium that minimizes DNA damage in the aging dog prostate remarkably parallels the selenium concentration in men that minimizes prostate cancer risk. By studying elderly dogs, the only non-human animal model of spontaneous prostate cancer, we have established a new approach to bridge the gap between laboratory and human studies that can be used to select the appropriate dose of anticancer agents for large-scale human cancer prevention trials. From the U-shaped dose-response, it follows that not all men will necessarily benefit from increasing their selenium intake and that measurement of baseline nutrient status should be required for all individuals in prevention trials to avoid oversupplementation.


Asunto(s)
Antioxidantes/farmacología , Daño del ADN , Neoplasias de la Próstata/prevención & control , Selenio/farmacología , Factores de Edad , Animales , Antioxidantes/administración & dosificación , Suplementos Dietéticos , Modelos Animales de Enfermedad , Perros , Relación Dosis-Respuesta a Droga , Humanos , Masculino , Neoplasias de la Próstata/veterinaria , Distribución Aleatoria , Selenio/administración & dosificación
9.
BJU Int ; 94(9): 1275-8, 2004 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-15610104

RESUMEN

OBJECTIVE: To assess the effects of hyperbaric oxygen (HBO2; often used to treat haemorrhagic cystitis, a known side-effect after radiation therapy for prostate cancer and with the potential to induce tumour angiogenesis and stimulate latent recurrence) on indolent in vivo prostate cancer in a murine model. MATERIALS AND METHODS: Human prostate LNCaP cells were injected into 60 severe combined-immunodeficient mice; of these 24 (40%) did not develop palpable tumours after 6 weeks. They were randomized to undergo 20 sessions of either HBO2 or normobaric air in standardized conditions, and observed for another 4 weeks before the histological assessment of any palpable tumours that developed. Analysis of developed LNCaP tumours included tumour volume, microvessel density, MIB-1, p53, p27 and racemase staining intensity. RESULTS: HBO2 was associated with less prostate tumour progression than normobaric air (P = 0.26). During HBO2 therapy, 10 mice remained free of palpable tumours, compared with seven controls (P = 0.30). On evaluation during the 4 weeks after therapy, six mice treated with HBO2 remained free of palpable tumours, vs eight of the controls (P = 0.17). There was tumour invasion and necrosis in a two of six and four of the HBO2 group during and after therapy, respectively, vs five and seven of the controls. Tumour microvessel density, proliferative index, differentiation and apoptosis markers were similar in both groups. CONCLUSIONS: HBO2 does not accelerate the growth of indolent prostate cancer in a murine model, suggesting that it does not increase the risk of residual prostate cancer reactivation when it is used to manage radiation-induced haemorrhagic cystitis in patients treated by pelvic radiotherapy for prostate cancer.


Asunto(s)
Cistitis/terapia , Hemorragia/terapia , Oxigenoterapia Hiperbárica/efectos adversos , Neoplasias de la Próstata/etiología , Traumatismos por Radiación/terapia , Animales , Cistitis/etiología , Hemorragia/etiología , Inmunohistoquímica/métodos , Masculino , Ratones , Ratones SCID , Traumatismos por Radiación/etiología , Vejiga Urinaria/efectos de la radiación
10.
J Endourol ; 18(1): 83-104, 2004 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-15006061

RESUMEN

BACKGROUND AND PURPOSE: Small renal tumors are often serendipitously detected during the screening of patients for renal or other disease entities. Rather than perform a radical or partial nephrectomy for these diminutive lesions, several centers have begun to explore a variety of ablative energy sources that could be applied directly via a percutaneously placed needle-like probe. To evaluate the utility of such treatment for small renal tumors/masses, we compared the feasibility, regularity (consistency in size and shape), and reproducibility of necrosis produced in normal porcine kidneys by different modes of tissue ablation: microwaves, cold impedance-based and temperature-based radiofrequency (RF) energy (monopolar and bipolar), and chemical. Chemoablation was accomplished using ethanol gel, hypertonic saline gel, and acetic acid gel either alone or with simultaneous application of monopolar or bipolar RF energy. MATERIALS AND METHODS: A total of 107 renal lesions were created laparoscopically in 33 domestic pigs. Microwave thermoablation (N=12) was done using a Targis T3 (Urologix) 10F antenna. Cryoablation (N=16) was done using a single 1.5-mm probe or three 17F microprobes (17F SeedNet system; Galil Medical) (N=10 single probe and N=6 three probes); a double freeze cycle with a passive thaw was employed under ultrasound guidance. Dry RF lesions were created using custom-made 18-gauge single-needle monopolar probe with two or three exposed metal tips (GelTx) (N=12) or a single-needle bipolar probe (N=6) at 50 W of 510 kHz RF energy for 5 minutes. In addition, a multitine RF probe (RITA Medical Systems) was used in one set of studies (N=6). Both impedance- and temperature-based RF were evaluated. Chemoablation was performed with 95% ethanol (4 mL), 24% hypertonic saline (4 mL), and 50% acetic acid (4 mL) as single injections. In addition, chemoablation was tested with monopolar and bipolar RF (wet RF). Tissues were harvested 1 week after ablation for light microscopy. RESULTS: In 11 of the 15 ablation techniques, there was complete necrosis in all lesions; however, three ethanol gel lesions had skip areas, three hypertonic saline gel lesions showed no necrosis or injury, and one monopolar RF and one bipolar RF lesion showed skip areas. In contrast to impedance-based RF, heat-based RF (RITA) caused complete necrosis without skip areas. All cryolesions resulted in complete tissue necrosis, and cryotherapy was the only modality for which lesion size could be effectively monitored using ultrasound imaging. CONCLUSIONS: Cryoablation and thermotherapy produce well-delineated, completely necrotic renal lesions. The single-probe monopolar and bipolar RF produce limited areas of tissue necrosis; however, both are enhanced by using hypertonic saline, acetic acid, or ethanol gel. Hypertonic saline gel with RF consistently provided the largest lesions. Ethanol and hypertonic saline gels tested alone failed to produce consistent cellular necrosis at 1 week. In contrast, RITA using the Starburst XL probe produced consistent necrosis, while impedance-based RF left skip areas of viable tissue. Renal cryotherapy under ultrasound surveillance produced hypoechoic lesions, which could be reasonably monitored, while all other modalities yielded hyperechoic lesions the margins of which could not be properly monitored with ultrasound imaging.


Asunto(s)
Ablación por Catéter , Criocirugía , Impedancia Eléctrica/uso terapéutico , Calor/uso terapéutico , Riñón/cirugía , Microondas/uso terapéutico , Ácido Acético/uso terapéutico , Animales , Etanol/uso terapéutico , Geles , Humanos , Riñón/patología , Neoplasias Renales/cirugía , Necrosis , Agujas , Solución Salina Hipertónica/uso terapéutico
11.
Urology ; 62(5): 900-4, 2003 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-14624916

RESUMEN

OBJECTIVES: To explore the use of magnetic resonance imaging (MRI) with gadolinium enhancement as a noninvasive method to image the extent of ablation after minimally invasive treatment. Minimally invasive methods for ablating prostatic tissue have emerged as a viable option in the treatment of prostate disease. As these devices enter the mainstream of patient care, imaging methods that verify the exact location, extent, and pattern of the ablation are needed. METHODS: Nineteen patients with prostate cancer were evaluated. All received some type of minimally invasive treatment, post-treatment gadolinium-enhanced MRI sequences, and radical retropubic prostatectomy for histopathologic evaluation. Visual comparisons of gadolinium defects and areas of coagulation necrosis as seen on histopathologic evaluation were made by us. Volumetric and two-dimensional area measurements of the ablation lesions were also compared for correlation between the MRI and histopathologic results. RESULTS: Gadolinium-enhanced MRI could be matched to histopathologic findings by visual comparison in 17 of the 19 cases. Surgically distorted histopathologic specimens and a small periurethral lesion caused 2 patients to have MRI and histopathologic results that could not be matched. Complete volumetric measurements were available for 16 of the 19 patients and correlated strongly (r = 0.924). The two-dimensional area data for all patients also showed significant correlation (r = 0.886). CONCLUSIONS: Correlation with histopathologic findings showed gadolinium-enhanced MRI to be useful for determining the location, pattern, and extent of necrosis caused within the prostate by minimally invasive techniques. Gadolinium-enhanced MRI gives the urologist a useful tool to evaluate the effectiveness of new minimally invasive therapies.


Asunto(s)
Adenocarcinoma/patología , Medios de Contraste , Gadolinio , Imagen por Resonancia Magnética/métodos , Neoplasias de la Próstata/patología , Adenocarcinoma/cirugía , Crioterapia , Humanos , Hipertermia Inducida , Masculino , Procedimientos Quirúrgicos Mínimamente Invasivos , Necrosis , Prostatectomía , Neoplasias de la Próstata/cirugía
12.
J Urol ; 170(3): 874-8, 2003 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-12913720

RESUMEN

PURPOSE: We determined patient tolerance and the sequence of histopathological changes of thermal injury and healing of the prostate after treatment with a novel, rapid, high temperature, liquid filled, flexible balloon thermotherapy system. MATERIALS AND METHODS: A total of 17 patients scheduled for prostatic surgery received preoperative high temperature water balloon thermotherapy. In 13 patients intraprostatic, urethral and rectal temperatures were continuously monitored and determined using stereotactic thermal mapping with the patient under spinal anesthesia. The remaining 4 patients had lidocaine gel as the only method of pain control. Patient discomfort was recorded at all times during the procedure. After treatment a prostatic stent was left in place until surgery or spontaneous voiding. Serial sections of the resected prostates were evaluated pathologically with mapping. RESULTS: Treatment was well tolerated by all patients. Prostates were enucleated (in 12 patients) or entirely removed (in 5) at a mean of 35 days (range 15 to 173) after thermotherapy. The predominant pathological findings in the early phase were uniform periurethral hemorrhagic necrosis, extensive urothelial denudation and varying degrees of inflammation. The mean radial depth of necrosis (from the urethra to the viable tissue border) was 0.9 cm (range 0.6 to 1.5) involving a mean of 16% of the prostatic adenoma (range 7.8% to 32%). In the late (resolution) phase necrotic tissue had been replaced by scar tissue (fibrosis and hyalinization) with a mean radial depth of 0.13 cm (range 0.01 to 0.24), and the urothelium had largely regrown along the urethra. CONCLUSIONS: The fast liquid ablation system for hyperplasia is a new minimally invasive treatment that induces considerable thermal injury to the prostate with uniform necrosis and subsequent sloughing of dead tissue, allowing enlargement of the urethral lumen.


Asunto(s)
Hipertermia Inducida/métodos , Hiperplasia Prostática/terapia , Anciano , Calor/uso terapéutico , Humanos , Masculino , Persona de Mediana Edad , Necrosis , Próstata/patología , Prostatectomía , Hiperplasia Prostática/patología , Hiperplasia Prostática/cirugía
13.
J Urol ; 170(1): 12-9, 2003 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-12796636

RESUMEN

PURPOSE: Benign prostatic hyperplasia (BPH) is near universal in aging men, creating tremendous costs in morbidity and surgical treatment. In the last decade numerous nonsurgical minimally invasive methods have emerged for ablation of prostatic tissue. MATERIALS AND METHODS: We reviewed the recently published English language literature on minimally invasive techniques for treating BPH and cancer with an emphasis on histopathological findings. RESULTS: We compared the spectrum of contemporary minimally invasive treatments for BPH and cancer, with an emphasis on histopathological results. Clinical results were summarized briefly for each treatment method. These procedures ablate tissue by thermal, cryogenic, chemical or enzymatic injury. The 5-year results for some techniques were promising, although long-term durability is still uncertain, and other methods were in preclinical or early clinical stages. Invariably the treated tissue was devitalized with a thin border of granulation tissue and fibrosis. These procedures have applications for BPH and prostate cancer, although some studies are limited to only 1 disease. CONCLUSIONS: Minimally invasive procedures show promise of a durable replacement for surgical resection.


Asunto(s)
Hiperplasia Prostática/patología , Hiperplasia Prostática/terapia , Neoplasias de la Próstata/patología , Neoplasias de la Próstata/terapia , Animales , Criocirugía , Calor/uso terapéutico , Humanos , Masculino , Procedimientos Quirúrgicos Mínimamente Invasivos , Necrosis , Hiperplasia Prostática/cirugía , Neoplasias de la Próstata/cirugía , Resección Transuretral de la Próstata , Terapia por Ultrasonido , Cateterismo Urinario
14.
J Natl Cancer Inst ; 95(3): 237-41, 2003 Feb 05.
Artículo en Inglés | MEDLINE | ID: mdl-12569146

RESUMEN

The trace mineral selenium inhibits cancer development in a variety of experimental animal models. We used an in vivo canine model to evaluate the effects of dietary selenium supplementation on DNA damage in prostate tissue and on apoptosis in prostate epithelial cells. Sexually intact elderly male beagle dogs were randomly assigned to receive an unsupplemented diet (control group) or diets that were supplemented with selenium (treatment group), either as selenomethionine or as high-selenium yeast at 3 micro g/kg or 6 micro g/kg body weight per day for 7 months. The extent of DNA damage in prostate cells and in peripheral blood lymphocytes, as determined by the alkaline comet assay, was lower among the selenium-supplemented dogs than among the control dogs (prostate P<.001; peripheral blood lymphocytes P =.003; analysis of variance) but was not associated with the activity of the antioxidant enzyme glutathione peroxidase in plasma. The median number of terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling-positive (i.e., apoptotic) prostate epithelial cells was 3.7 (interquartile range = 1.1-7.6) for the selenium-supplemented dogs and 1.7 (interquartile range = 0.2-2.8) for the control dogs ( P =.04, Mann-Whitney U test). These data suggest that dietary selenium supplementation decreases DNA damage and increases epithelial cell apoptosis within the aging canine prostate.


Asunto(s)
Apoptosis/efectos de los fármacos , Daño del ADN/efectos de los fármacos , Suplementos Dietéticos , Próstata/efectos de los fármacos , Próstata/patología , Compuestos de Selenio/administración & dosificación , Animales , Perros , Linfocitos , Masculino , Neoplasias de la Próstata/prevención & control , Distribución Aleatoria , Urotelio/efectos de los fármacos , Urotelio/patología
15.
J Endourol ; 16(7): 523-31, 2002 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-12396447

RESUMEN

BACKGROUND AND PURPOSE: Ferromagnetic compounds, when placed in a radiofrequency magnetic field, develop an electrical current. When placed in tissue, resistance to the transmission of the electrical current leads to heating of the tissues next to the ferromagnetic compound. The Curie temperature is a transition point at which the development of a particular temperature within the material results in loss of its magnetic properties; as such, when this temperature is reached, there is cessation of current, and thus heat production stops. Our goal was to examine the ablative impact of permanently implanted palladium and cobalt self-regulating temperature rods on solid abdominal and pelvic organs. These rods were designed to develop a maximum temperature of 70 degrees C. MATERIALS AND METHODS: In 16 pigs, renal, hepatic, uterine, and pancreatic ferromagnetic rods were placed using a template. The rods were delivered in 1-cm parallel rows of two rods each in order to ablate 7 g of tissue. The animals were subsequently treated in an extracorporeal magnetic field of 50 gauss rms at a frequency of 50 kHz. The position of the rods was confirmed by fluoroscopy before the animal was put in the magnetic field. The animals received one or two treatment sessions. Intralesional and extralesional temperatures were measured continuously. Serum chemistry was analyzed before surgery, after each treatment, and at the time of harvest. Two weeks following therapy, the treated tissues were harvested and examined histopathologically. RESULTS: In all tissues with properly aligned rods, the temperature of the tissue surrounding the rods exceeded 50 degrees C. Histologic review showed confluent tissue necrosis in 7 of 9 kidneys (78%), 6 of 9 livers (67%), 1 of 3 pancreases (33%), and 1 of 3 uterine specimens (33%). Necrosis extended for 2 mm beyond the periphery of the rods. All failures were secondary to technical misalignment of the rods, which occurred because of our attempt to treat more than one organ in each animal. CONCLUSIONS: Ferromagnetic rods, when properly aligned in a magnetic field, create well-defined areas of necrosis. There are no skip areas of viable tissue within the treated area, and there is a precipitous fall-off of injury just outside the area of treatment. Also, because the rods can be reactivated at any time, recurrent lesions within the same site can be treated. This form of minimally invasive in situ ablative therapy appears promising. Clinical trials in the kidney and in other abdominal and pelvic organs are pending.


Asunto(s)
Campos Electromagnéticos , Calor/uso terapéutico , Hipertermia Inducida/instrumentación , Hipertermia Inducida/métodos , Prótesis e Implantes , Animales , Materiales Biocompatibles/uso terapéutico , Calorimetría , Femenino , Compuestos Férricos , Riñón/patología , Riñón/efectos de la radiación , Hígado/patología , Ensayo de Materiales , Necrosis , Neoplasias/terapia , Páncreas/patología , Terapia por Radiofrecuencia , Porcinos , Útero/patología
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA