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1.
Contemp Clin Trials ; 142: 107564, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38704119

RESUMEN

INTRODUCTION: Women with atypical hyperplasia (AH) or lobular carcinoma in situ (LCIS) have a significantly increased risk of breast cancer, which can be substantially reduced with antiestrogen therapy for chemoprevention. However, antiestrogen therapy for breast cancer risk reduction remains underutilized. Improving knowledge about breast cancer risk and chemoprevention among high-risk patients and their healthcare providers may enhance informed decision-making about this critical breast cancer risk reduction strategy. METHODS/DESIGN: We are conducting a cluster randomized controlled trial to evaluate the effectiveness and implementation of patient and provider decision support tools to improve informed choice about chemoprevention among women with AH or LCIS. We have cluster randomized 26 sites across the U.S. through the SWOG Cancer Research Network. A total of 415 patients and 200 healthcare providers are being recruited. They are assigned to standard educational materials alone or combined with the web-based decision support tools. Patient-reported and clinical outcomes are assessed at baseline, after a follow-up visit at 6 months, and yearly for 5 years. The primary outcome is chemoprevention informed choice after the follow-up visit. Secondary endpoints include other patient-reported outcomes, such as chemoprevention knowledge, decision conflict and regret, and self-reported chemoprevention usage. Barriers and facilitators to implementing decision support into clinic workflow are assessed through patient and provider interviews at baseline and mid-implementation. RESULTS/DISCUSSION: With this hybrid effectiveness/implementation study, we seek to evaluate if a multi-level intervention effectively promotes informed decision-making about chemoprevention and provide valuable insights on how the intervention is implemented in U.S. TRIAL REGISTRATION: NCT04496739.


Asunto(s)
Neoplasias de la Mama , Quimioprevención , Humanos , Femenino , Neoplasias de la Mama/prevención & control , Quimioprevención/métodos , Educación del Paciente como Asunto/métodos , Técnicas de Apoyo para la Decisión , Persona de Mediana Edad , Adulto , Toma de Decisiones , Conocimientos, Actitudes y Práctica en Salud , Conducta de Reducción del Riesgo , Proyectos de Investigación , Antagonistas de Estrógenos/uso terapéutico , Antagonistas de Estrógenos/administración & dosificación , Medición de Resultados Informados por el Paciente
2.
J Natl Cancer Inst ; 108(3)2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-26668177

RESUMEN

BACKGROUND: While progestin addition to estrogen mitigates endometrial cancer risk, the magnitude of the effect on incidence, specific endometrial cancer histologies, and endometrial cancer mortality remains unsettled. These issues were assessed by analyses after extended follow-up of the Women's Health Initiative (WHI) randomized clinical trial evaluating continuous combined estrogen plus progestin use. METHODS: The WHI enrolled 16 608 postmenopausal women into a randomly assigned, double-blind, placebo-controlled trial. Women age 50 to 79 years with intact uteri with normal endometrial biopsy at entry were randomly assigned to once-daily 0.625 mg conjugated equine estrogen plus 2.5mg medroxyprogesterone acetate (n = 8506) as a single pill or matching placebo (n = 8102). Follow-up beyond the original trial completion date required reconsent, obtained from 12 788 (83%) of surviving participants. Analyses were by intent-to-treat. All statistical tests were two-sided. RESULTS: After 5.6 years' median intervention and 13 years' median cumulative follow-up, there were fewer endometrial cancers in the combined hormone therapy compared with the placebo group (66 vs 95 case patients, yearly incidence, 0.06% vs 0.10%; hazard ratio [HR] = 0.65, 95% confidence interval [CI] = 0.48 to 0.89, P = .007). While there were somewhat fewer endometrial cancers during intervention (25 vs 30, respectively; HR = 0.77, 95% CI = 0.45 to 1.31), the difference became statistically significant postintervention (41 vs 65, respectively; HR = 0.59, 95% CI = 0.40 to 0.88, P = .008), but hazard ratios did not differ between phases (P difference = .46). There was a statistically nonsignificant reduction in deaths from endometrial cancer in the estrogen plus progestin group (5 vs 11 deaths, HR = 0.42, 95% CI = 0.15 to 1.22). CONCLUSION: In postmenopausal women, continuous combined estrogen plus progestin decreases endometrial cancer incidence.


Asunto(s)
Neoplasias Endometriales/inducido químicamente , Neoplasias Endometriales/epidemiología , Terapia de Reemplazo de Estrógeno , Estrógenos Conjugados (USP)/administración & dosificación , Estrógenos Conjugados (USP)/efectos adversos , Acetato de Medroxiprogesterona/administración & dosificación , Acetato de Medroxiprogesterona/efectos adversos , Anciano , Método Doble Ciego , Esquema de Medicación , Neoplasias Endometriales/mortalidad , Neoplasias Endometriales/cirugía , Terapia de Reemplazo de Estrógeno/efectos adversos , Terapia de Reemplazo de Estrógeno/métodos , Femenino , Humanos , Histerectomía , Incidencia , Estimación de Kaplan-Meier , Persona de Mediana Edad , Oportunidad Relativa , Posmenopausia , Estados Unidos/epidemiología , Salud de la Mujer
3.
Climacteric ; 18(3): 336-8, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-25966858

RESUMEN

In an invited editorial, Dr Shapiro proposes that vaginal bleeding leading to unblinding and subsequent detection bias explains the breast cancer increase seen with estrogen plus progestin in the Women's Health Initiative (WHI) clinical trial (1) . In the context of a uniform detection program of protocol-mandated annual mammography and breast examinations, such a proposal is medically implausible. Dr Shapiro suggests detection bias would identify a larger number of 'slowly growing tumors that would otherwise remain clinically silent'. The findings of more advanced cancers with increased deaths from breast cancer in the estrogen plus progestin group refute this conjecture. During early post-intervention phases of both WHI hormone therapy trials, when breast cancer detection bias is asserted by Dr Shapiro because participants had been informed of randomization assignment, breast cancer incidence rates were lower (rather than higher) than during intervention. Thus, Dr Shapiro's claims are directly refuted by findings from the WHI randomized clinical trials. Health-care providers should be aware that randomized clinical trial evidence supports estrogen plus progestin increasing breast cancer incidence and deaths from breast cancer. In contrast, among women with prior hysterectomy, randomized clinical trial evidence supports estrogen alone reducing breast cancer incidence and deaths from breast cancer.


Asunto(s)
Neoplasias de la Mama/tratamiento farmacológico , Neoplasias de la Mama/mortalidad , Terapia de Reemplazo de Estrógeno/métodos , Estrógenos/uso terapéutico , Progestinas/uso terapéutico , Sesgo , Femenino , Humanos , Mamografía , Posmenopausia , Ensayos Clínicos Controlados Aleatorios como Asunto
4.
Climacteric ; 18(3): 343-5, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-25966859

RESUMEN

The impact of the findings from the Women's Health Initiative trial of estrogen plus progestin cannot be attributed to any real or imagined conflicts of interest between government, researchers, and journals. Rather, the findings overturned decades of dogma in part promoted by the pharmaceutical industry, and the reaction to these unexpected findings was in direct proportion to their importance in reversing a misguided practice of prescribing the drug for chronic disease prevention. The findings have been widely accepted, as shown by the sustained subsequent reduction in prescriptions. However, conflicts of interest may influence a minority unwilling to accept the findings. The decrease in the use of a drug with an adverse risk profile for prevention of chronic disease is a public good.


Asunto(s)
Investigación Biomédica/economía , Conflicto de Intereses , Gobierno , Investigadores/ética , Apoyo a la Investigación como Asunto , Humanos
5.
Osteoporos Int ; 24(2): 567-80, 2013 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-23208074

RESUMEN

SUMMARY: The Women's Health Initiative (WHI) double-blind, placebo-controlled clinical trial randomly assigned 36,282 postmenopausal women in the U.S. to 1,000 mg elemental calcium carbonate plus 400 IU of vitamin D(3) daily or placebo, with average intervention period of 7.0 years. The trial was designed to test whether calcium plus vitamin D supplementation in a population in which the use of these supplements was widespread would reduce hip fracture, and secondarily, total fracture and colorectal cancer. INTRODUCTION: This study further examines the health benefits and risks of calcium and vitamin D supplementation using WHI data, with emphasis on fractures, cardiovascular disease, cancer, and total mortality. METHODS: WHI calcium and vitamin D randomized clinical trial (CT) data through the end of the intervention period were further analyzed with emphasis on treatment effects in relation to duration of supplementation, and these data were contrasted and combined with corresponding data from the WHI prospective observational study (OS). RESULTS: Among women not taking personal calcium or vitamin D supplements at baseline, the hazard ratio [HR] for hip fracture occurrence in the CT following 5 or more years of calcium and vitamin D supplementation versus placebo was 0.62 (95 % confidence interval (CI), 0.38-1.00). In combined analyses of CT and OS data, the corresponding HR was 0.65 (95 % CI, 0.44-0.98). Supplementation effects were not apparent on the risks of myocardial infarction, coronary heart disease, total heart disease, stroke, overall cardiovascular disease, colorectal cancer, or total mortality, while evidence for a reduction in breast cancer risk and total invasive cancer risk among calcium plus vitamin D users was only suggestive. CONCLUSION: Though based primarily on a subset analysis, long-term use of calcium and vitamin D appears to confer a reduction that may be substantial in the risk of hip fracture among postmenopausal women. Other health benefits and risks of supplementation at doses considered, including an elevation in urinary tract stone formation, appear to be modest and approximately balanced.


Asunto(s)
Conservadores de la Densidad Ósea/uso terapéutico , Carbonato de Calcio/uso terapéutico , Colecalciferol/uso terapéutico , Suplementos Dietéticos/efectos adversos , Fracturas Osteoporóticas/prevención & control , Anciano , Conservadores de la Densidad Ósea/administración & dosificación , Conservadores de la Densidad Ósea/efectos adversos , Carbonato de Calcio/administración & dosificación , Carbonato de Calcio/efectos adversos , Enfermedades Cardiovasculares/epidemiología , Enfermedades Cardiovasculares/prevención & control , Colecalciferol/administración & dosificación , Colecalciferol/efectos adversos , Método Doble Ciego , Esquema de Medicación , Quimioterapia Combinada , Femenino , Fracturas de Cadera/epidemiología , Fracturas de Cadera/etiología , Fracturas de Cadera/prevención & control , Humanos , Persona de Mediana Edad , Neoplasias/epidemiología , Neoplasias/prevención & control , Osteoporosis Posmenopáusica/complicaciones , Osteoporosis Posmenopáusica/tratamiento farmacológico , Osteoporosis Posmenopáusica/epidemiología , Fracturas Osteoporóticas/epidemiología , Medición de Riesgo/métodos , Estados Unidos/epidemiología , Cálculos Urinarios/inducido químicamente , Cálculos Urinarios/epidemiología
6.
J Food Prot ; 69(3): 660-5, 2006 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-16541700

RESUMEN

An estimated 2,500 cases of listeriosis occur annually in the United States. Listeriosis is particularly severe among pregnant women and immunocompromised individuals. Little is known regarding the effect of the food matrix on the ability of L. monocytogenes to survive in the gastrointestinal tract and cause systemic infection. Mice were inoculated with various doses of L. monocytogenes in skim milk, Half & Half, or whipping cream to determine whether differences in milk fat content influence the ability of L. monocytogenes to survive passage through the gut and infect the liver or spleen. The number of fecal samples positive for L. monocytogenes increased with increasing doses of L. monocytogenes for all three vehicles. The number of L. monocytogenes cells isolated from liver or spleen of mice dosed with L. monocytogenes was not significantly different among treatment vehicles. Dose-response models revealed that as the dosage of L. monocytogenes was increased in different milk vehicles, the number of L. monocytogenes cells in liver or spleen also increased. Although fat content of food had no dose-dependent effect on L. monocytogenes infection in the murine gastrointestinal tract, we cannot discount the possibility that it may be a factor in L. monocytogenes infections of humans because of differences in the physiology of gastrointestinal tracts of mice and humans.


Asunto(s)
Grasas de la Dieta/farmacología , Listeria monocytogenes/crecimiento & desarrollo , Listeria monocytogenes/patogenicidad , Listeriosis/microbiología , Leche/química , Animales , Recuento de Colonia Microbiana , Modelos Animales de Enfermedad , Heces/microbiología , Femenino , Humanos , Listeria monocytogenes/efectos de los fármacos , Hígado/microbiología , Ratones , Ratones Endogámicos BALB C , Organismos Libres de Patógenos Específicos , Bazo/microbiología
7.
Hand Clin ; 17(3): 357-69, viii, 2001 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-11599206

RESUMEN

Ischemia and reperfusion in skeletal muscle is unavoidable during many reconstructive surgeries. Typical examples include replantation, transplantation, and free muscle transfer. One important complication during or after surgery is arterial insufficiency or a no-reflow phenomenon. The microcirculation is a primary target of ischemia and reperfusion injury. Vasoconstriction, poor blood flow, and capillary no-reflow, are the prominent features in the microcirculation seen during reperfusion. Currently, extensive efforts have focused on the theory that reactive oxygen species induce endothelial dysfunction in the microcirculation during reperfusion. Some intervention approaches, including ischemic preconditioning, are developing to interfere with or modulate the pathophysiological processes that are set in motion during ischemia and reperfusion.


Asunto(s)
Procedimientos de Cirugía Plástica , Daño por Reperfusión , Arteriopatías Oclusivas , Endotelio Vascular/fisiopatología , Depuradores de Radicales Libres , Humanos , Precondicionamiento Isquémico , Microcirculación/fisiología , Músculo Esquelético/inervación , Flujo Sanguíneo Regional , Daño por Reperfusión/fisiopatología , Daño por Reperfusión/prevención & control , Vasoconstricción/fisiología
8.
J Surg Res ; 99(1): 92-9, 2001 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-11421609

RESUMEN

PURPOSE: The goal of these studies was to determine the initiating factors for late preconditioning in the microcirculation of skeletal muscle. MATERIALS AND METHODS: The cremaster muscle of male Sprague-Dawley rats underwent 4 h of ischemia and then 60 min of reperfusion. Ischemic preconditioning (IPC) consisted of 45 min of ischemia but was done 24 h before the 4 h of ischemia. To mimic the effects of IPC in the late phase, adenosine (ADO) or sodium nitroprusside (SNP) was given 24 h before the prolonged ischemia via local intraarterial infusion. To block the effects of IPC in the late phase, 8-sulfophenyl-theophylline (a nonspecific ADO receptor blocker) or N(W)-nitro-l-arginine (a nonselective nitric oxide synthase antagonist) was given prior to IPC. Microvascular response to IPC and pharmacological preconditioning were determined by measuring arteriole diameters and capillary perfusion using intravital microscopy. RESULTS: Administration of ADO or SNP on day 1 without IPC produced a similar microvascular protection against prolonged ischemia/reperfusion on day 2 as that induced by IPC alone. In contrast, blocking ADO receptors or nitric oxide synthase on day 1 just prior to IPC eliminated the IPC-induced microvascular protection seen on day 2. In addition, inhibition of nitric oxide synthase on day 1 diminished the protection induced by ADO, but blocking ADO receptors on day 1 did not compromise the protection induced by SNP. CONCLUSION: The results from these studies suggest that up regulation of ADO is the initiating factor with secondary up regulation of nitric oxide in late preconditioning. Both ADO and nitric oxide contribute to initiating microvascular protection in the late phase of IPC.


Asunto(s)
Precondicionamiento Isquémico , Músculo Esquelético/irrigación sanguínea , Músculo Esquelético/fisiopatología , Adenosina/farmacología , Animales , Arteriolas/efectos de los fármacos , Arteriolas/fisiopatología , Capilares/efectos de los fármacos , Capilares/fisiopatología , Inhibidores Enzimáticos/farmacología , Masculino , Músculo Esquelético/efectos de los fármacos , Óxido Nítrico Sintasa/antagonistas & inhibidores , Nitroprusiato/farmacología , Antagonistas de Receptores Purinérgicos P1 , Ratas , Ratas Sprague-Dawley , Factores de Tiempo , Vasodilatadores/farmacología
9.
Environ Toxicol Chem ; 20(4): 833-8, 2001 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-11345460

RESUMEN

Toxicity tests in invertebrates often use sublethal endpoints, which may exhibit different sensitivity for various toxicants. Our objective was to characterize the sensitivity of movement, feeding, growth, and reproduction as endpoints for heavy metal toxicity testing with Caenorhabditis elegans. Growth and feeding were assessed in the same nematode samples used to assess movement and reproduction. Median effective concentrations (EC50s) for 24-h exposures to Pb, Cu, and Cd were determined for movement, feeding, and growth and a 72-h EC50 was derived for reproduction. The order of toxicity was Cu > Pb > Cd for each endpoint, including lethality and movement. There were no differences in sensitivity among endpoints for any metal. When exposed for 4 h at (sublethal) concentrations that were 14 times the 24-h EC50 value, Pb and Cu reduced feeding to the same extent while movement was reduced significantly more by Pb than by Cu. Thus, a difference in sensitivity of endpoints was apparent at 4 h, which was not evident at 24 h. These observations suggest potentially different mechanisms of toxicity for 24- and 4-h tests.


Asunto(s)
Caenorhabditis elegans/fisiología , Metales/toxicidad , Animales , Cadmio/toxicidad , Caenorhabditis elegans/efectos de los fármacos , Caenorhabditis elegans/crecimiento & desarrollo , Cobre/toxicidad , Conducta Alimentaria/efectos de los fármacos , Femenino , Sustancias Peligrosas/toxicidad , Larva , Plomo/toxicidad , Movimiento/efectos de los fármacos , Movimiento/fisiología , Oviposición/efectos de los fármacos , Reproducción/efectos de los fármacos , Reproducción/fisiología , Toxicología/métodos
10.
J Reconstr Microsurg ; 16(8): 621-8, 2000 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-11127285

RESUMEN

The authors hypothesized that nitric oxide is induced by a brief period of ischemia/reperfusion (ischemic preconditioning, IPC) on postoperative day (POD) 1, and that this released nitric oxide is responsible for initiating a delayed microvascular protection against a prolonged period of ischemia in skeletal muscle on POD day 2. The cremaster muscle of male Sprague-Dawley rats underwent 4 hr of ischemia, and then 60 min of reperfusion. IPC consisted of 45 min of ischemia but was done 24 hr before the prolonged ischemia. Local intraarterial infusion of sodium nitroprusside (SNP, a donor of nitric oxide) or Nw-nitro-L-arginine (L-NA, a nonselective nitric oxide synthase antagonist) were also given 24 hr before prolonged ischemia. Arteriole diameters and capillary perfusion were measured using intravital microscopy. Four groups were compared: 1) control; 2) IPC; 3) SNP + sham IPC; and 4) L-NA + IPC. Four hours of ischemia followed by reperfusion created a significant vasoconstriction and capillary no-reflow in the microcirculation of cremaster muscles. These alterations were largely prevented by IPC. Local intraarterial infusion of SNP without IPC created a similar microvascular protection to that induced by IPC alone. In contrast, intraarterial infusion of L-NA prior to IPC eliminated the IPC-induced microvascular protection. In conclusion, in late preconditioning, nitric oxide contributes to the initiation of a delayed microvascular protection against prolonged ischemia in skeletal muscle.


Asunto(s)
Precondicionamiento Isquémico , Músculo Esquelético/irrigación sanguínea , Óxido Nítrico/fisiología , Animales , Presión Sanguínea , Masculino , Ratas , Ratas Sprague-Dawley , Factores de Tiempo
11.
J Surg Res ; 92(1): 18-22, 2000 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-10864476

RESUMEN

TNP-470 is a synthetic analogue of fumagillin that acts as a potent angiogenesis inhibitor. Recently, our laboratory demonstrated that systemic administration of TNP-470 (5.0 mg/kg) decreased the rate of cutaneous wound healing by greater than 20%. In this study, we tested the hypothesis that TNP-470 interferes with the wound repair-stimulating action of basic fibroblast growth factor (bFGF) by competing with endogenous bFGF for its binding sites on the receptor protein. The influence of TNP-470 was examined in vitro in a ligand competition assay of high- and low-affinity receptor binding to (125)I-bFGF in NIH/3T3 cells. Results demonstrated that recognition of (125)I-bFGF by low-affinity growth factor binding sites was significantly decreased (P < 0.01) in the presence of TNP-470. However, TNP-470 inhibition of radiolabeled bFGF binding to high-affinity sites was not significantly affected (P = 0.07). In view of recent studies demonstrating that the low-affinity receptors of bFGF were heparan sulfate proteoglycans, we suggest that the influence of TNP-470 on diminished wound healing is due to its direct recognition by these molecules.


Asunto(s)
Inhibidores de la Angiogénesis/farmacología , Receptores de Factores de Crecimiento de Fibroblastos/metabolismo , Sesquiterpenos/farmacología , Cicatrización de Heridas/efectos de los fármacos , Células 3T3 , Inhibidores de la Angiogénesis/metabolismo , Animales , Sitios de Unión/fisiología , Ciclohexanos , Factor 2 de Crecimiento de Fibroblastos/metabolismo , Radioisótopos de Yodo , Ratones , O-(Cloroacetilcarbamoil) Fumagilol , Receptores de Factores de Crecimiento de Fibroblastos/química , Sesquiterpenos/metabolismo , Cicatrización de Heridas/fisiología
12.
J Surg Res ; 89(2): 139-46, 2000 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-10729242

RESUMEN

BACKGROUND: The purpose of the present study was to determine if platelet-activating factor is an important mediator that produces vasospasm during reperfusion after ischemia in skeletal muscle. MATERIALS AND METHODS: A vascular isolated cremaster muscle in male Sprague-Dawley rats was coupled with local intraarterial drug infusion as a model to study microcirculation responses to ischemia/reperfusion injury. Arteriole diameters and capillary perfusion were measured using intravital microscopy. Group 1: platelet-activating factor dose response. Group 2: Effects of a cyclooxygenase inhibitor; indomethacin, and a thromboxane synthetase inhibitor, imidazole, on the response to platelet-activating factor. Group 3: Effects of nitric oxide synthesis inhibitor; N(omega)-nitro-L-arginine methyl ester, on the response to platelet-activating factor. Group 4: Effects of a platelet-activating factor receptor antagonist, CV-3988, indomethacin, and imidazole after 4 h of warm ischemia and reperfusion. RESULTS: Intraarterial infusion of platelet-activating factor produced a dose-related but mild vasoconstriction. Pretreatment with indomethacin or imidazole resulted in significant vasodilation actually emanating from platelet-activating factor infusion. Nitric oxide inhibition (with N(omega)-nitro-L-arginine methyl ester) enhanced the vasoconstriction produced by platelet-activating factor. Pretreatment with CV-3988, indomethacin, or imidazole significantly attenuated ischemia/reperfusion-induced vasospasm and capillary no-reflow in the cremaster muscles. CONCLUSIONS: Ischemia/reperfusion-induced vasoconstriction is at least in part mediated by platelet-activating factor and thromboxane A(2).


Asunto(s)
Isquemia/fisiopatología , Músculo Esquelético/irrigación sanguínea , Factor de Activación Plaquetaria/fisiología , Vasoconstricción , Animales , Genitales Masculinos , Inyecciones Intraarteriales , Masculino , Microcirculación/efectos de los fármacos , Óxido Nítrico/antagonistas & inhibidores , Factor de Activación Plaquetaria/antagonistas & inhibidores , Factor de Activación Plaquetaria/farmacología , Ratas , Ratas Sprague-Dawley , Daño por Reperfusión/fisiopatología , Tromboxano A2/antagonistas & inhibidores , Factores de Tiempo , Vasoconstricción/efectos de los fármacos
13.
J Toxicol Environ Health A ; 61(8): 641-7, 2000 Dec 29.
Artículo en Inglés | MEDLINE | ID: mdl-11132694

RESUMEN

Caenorhabditis elegans has proven useful in toxicity testing of known toxicants, but its potential for assessing the toxicity of new pharmaceuticals is relatively unexplored. In this study the procedures used in aquatic testing of toxicants were modified to permit testing of small amounts (<40 mg) of gadolinium-based magnetic resonance imaging (MRI) compounds. Five blinded compounds were tested. The toxicity of these compounds determined using C. elegans was compared to existing mammalian test system data (minimum lethal dose [MLD] values for mice). Four of five compounds tested had the same relative sensitivity with C. elegans as with the mouse test system. Testing with C. elegans is efficient and could markedly reduce the cost of screening potentially useful compounds.


Asunto(s)
Alternativas a las Pruebas en Animales , Caenorhabditis elegans , Animales , Medios de Contraste/toxicidad , Control de Costos , Industria Farmacéutica , Imagen por Resonancia Magnética , Ratones , Sensibilidad y Especificidad , Pruebas de Toxicidad/métodos
14.
J Surg Res ; 87(1): 77-84, 1999 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-10527707

RESUMEN

Leukocyte-endothelium interaction in postcapillary venules plays an important role in reperfusion injury, inflammation, shock, and sepsis. This phenomenon is poorly described in precapillary arterioles. In fact, many researchers have reported no evidence of leukocyte adherence in arterioles whatsoever. Most research has focused on venules of larger rodents, in which observation of the microcirculation, especially arterioles, is limited. We have developed a model which provides a clearer view of these microvessels using the mouse cremaster muscle. This muscle has an approximate thickness of 100 microm allowing images produced by transillumination to be very clear. After vascular isolation, the right cremaster muscle was subjected to 4 h of ischemia, followed by 2 h of reperfusion. The left muscle was not rendered ischemic, thereby allowing it to serve as the animal's own internal control. We observed leukocyte rolling in arterioles in both the ischemic and the nonischemic muscles. Leukocyte sticking was seen in arterioles and venules on both sides, except in control arterioles. The number of rolling and sticking leukocytes on the ischemic side was significantly higher than in controls (P < 0.05) for both arterioles and venules. During the reperfusion period, this number did not change significantly. Transmigration of leukocytes was observed only in venules, but not in arterioles. The number of perfused capillaries was reduced on the ischemic side compared to controls and did not change significantly during the 2 h of reperfusion. Our results demonstrate that leukocyte-endothelium interaction occurs in muscle arterioles of mice. This phenomenon is more pronounced after ischemia and reperfusion, i.e., depends on the extent of tissue insult.


Asunto(s)
Arteriolas/fisiología , Endotelio Vascular/fisiología , Isquemia/fisiopatología , Leucocitos/fisiología , Músculo Esquelético/irrigación sanguínea , Daño por Reperfusión/etiología , Animales , Adhesión Celular , Masculino , Ratones , Vénulas/fisiología
15.
Br J Plast Surg ; 52(2): 133-42, 1999 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-10434893

RESUMEN

Vascular delay is a surgical procedure that renders a flap partially ischaemic several days prior to its transfer in order to increase its viability after its transfer. Though much debate exists regarding the actual mechanism of vascular delay, most theories agree that changes in the microcirculation play a key role. In this paper, we describe four experiments that establish the ear of the homozygous (hr/hr) hairless mouse as an effective model for directly viewing and measuring delay-induced changes in microcirculation. In our first experiment, we compared mouse ears that were delayed (n = 18) with ones that were not (control) (n = 13) and showed that vascular delay significantly (P < 0.05) reduced ear flap necrosis. In a second experiment, we delayed mouse ears for 2 (n = 9), 4 (n = 14), 6 (n = 10), 8 (n = 10), 10 (n = 10), 20 (n = 18), 40 (n = 10) and 80 (n = 11) days and found that the reduction in necrosis becomes statistically significant (P < 0.05) over non-delayed controls (n = 12) after a minimum delay period of 6 days. In a third experiment, we delayed mouse ears by ligating only the vein (n = 14), only the artery (n = 11), only the nerve (sympathectomy) (n = 14), and vein, artery and nerve (n = 14) of the main neurovascular pedicle and found significant (P < 0.05) reductions in flap necrosis in all groups compared to nondelayed controls (n = 12). Finally, in a fourth experiment, we measured vessel directionality changes in mouse ears that were delayed for 6 (n = 4), 10 (n = 4), 20 (n = 4), 40 (n = 4) and 80 (n = 4) days, and found that directionality changes became significant (P < 0.05) at 6 days of delay and remained so for all the days studied when compared with non-delayed controls (n = 4).


Asunto(s)
Modelos Animales de Enfermedad , Precondicionamiento Isquémico , Trasplante de Piel/fisiología , Colgajos Quirúrgicos/irrigación sanguínea , Animales , Oído Externo/irrigación sanguínea , Rechazo de Injerto/prevención & control , Ratones , Ratones Pelados , Microcirculación , Necrosis , Piel/patología , Trasplante de Piel/patología , Factores de Tiempo
16.
J Orthop Res ; 17(4): 571-7, 1999 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-10459764

RESUMEN

We investigated whether ischemic preconditioning induces microvascular protection in skeletal muscle at the late phase (after 24 hours) when the same muscles are subjected to prolonged warm global ischemia. The cremaster muscle of the male Sprague-Dawley rat underwent vascular isolation and was subjected to 4 hours of ischemia and 60 minutes of reperfusion. Early preconditioning consisted of 45 minutes of ischemia followed by 15 minutes of reperfusion before prolonged ischemia/reperfusion; late preconditioning also consisted of 45 minutes of ischemia but was done 24 hours (24-hour period of reperfusion) before the prolonged ischemia/reperfusion. Arteriole diameters and capillary perfusion were measured with use of intravital microscopy. Four groups were compared: rats that underwent early preconditioning, their controls, rats that underwent late preconditioning, and their controls. Early and late preconditioning significantly attenuated vasospasm and capillary no-reflow compared with the controls for each. Average arteriole diameter was significantly larger in the rats that underwent late preconditioning than in any other rats; it was also significantly larger in the controls for late preconditioning than in those for early preconditioning. We introduce a model of the rat cremaster muscle that has been isolated from its vascular supply as a useful preparation to study the effects of late preconditioning on microcirculation in skeletal muscle. Late preconditioning provided better microvascular protection than did early preconditioning. The mechanism for this preconditioning protection is being investigated because it should provide a means for therapeutic intervention.


Asunto(s)
Precondicionamiento Isquémico , Músculo Esquelético/irrigación sanguínea , Músculo Esquelético/inervación , Animales , Masculino , Microcirculación/anatomía & histología , Microcirculación/fisiología , Desnervación Muscular , Ratas , Ratas Sprague-Dawley , Factores de Tiempo
17.
Microsurgery ; 19(5): 214-22, 1999.
Artículo en Inglés | MEDLINE | ID: mdl-10413786

RESUMEN

In spite of the extensive experimental work on vascular washout in free flap surgery, an optimal temperature for the washout solution has not been established. This study was designed to determine the effect of the washout solution temperature on the degree to which the microcirculation is cleared of blood. The cremaster muscle flap in the rat was used, in which the microcirculation can be directly viewed and the presence of blood and perfusion parameters within various vessels can be measured during and after washout. Washout was started with a single, high-pressure infusion and continued at 130 mmHg for 15 minutes. The temperature of the washout solution was either 2-3, 20-22, or 35 degrees C. In all three groups, washout cleared the microcirculation almost completely within the first minute. However, we observed that a cold or room temperature washout cleared the microcirculation more completely than a warm washout did. The temperature of the washout solution did not effect post washout capillary perfusion and/or arterial diameters.


Asunto(s)
Colgajos Quirúrgicos/irrigación sanguínea , Animales , Modelos Animales de Enfermedad , Estudios de Evaluación como Asunto , Microcirculación , Perfusión , Distribución Aleatoria , Ratas , Ratas Sprague-Dawley , Temperatura
18.
Am Surg ; 65(7): 689-91; discussion 691-2, 1999 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-10399981

RESUMEN

Age less than 55 years, normal Glasgow Coma Score (GCS), and absence of hypotension are traditional criteria for the selection of adult patients with blunt splenic trauma for observation. The objective of this study is to challenge these criteria. Two hundred twelve patients who presented with blunt splenic injury between 1992 and 1997 were identified from the Trauma Registry at our Level I trauma center. The patients were divided into three groups: 100 patients (47%) were observed, 108 (51%) underwent immediate splenorrhaphy or splenectomy, and 4 (2%) failed observation. The three groups were compared by participants' ages, GCSs, and histories of hypotension. No statistical differences were noted between the successfully observed patients and those requiring immediate surgery with respect to these criteria. Of the 4 patients who failed observation, all were younger than 55 years, all had a GCS >12, and all were normotensive. Our findings suggest that traditional criteria used to select patients for splenic trauma observation are not absolute indicators and should be liberalized: patients can be successfully observed despite having criteria that, in the past, would have led to immediate operative intervention.


Asunto(s)
Selección de Paciente , Bazo/lesiones , Heridas no Penetrantes/cirugía , Presión Sanguínea , Escala de Coma de Glasgow , Humanos , Persona de Mediana Edad , Bazo/cirugía
19.
Circulation ; 99(15): 1997-2002, 1999 Apr 20.
Artículo en Inglés | MEDLINE | ID: mdl-10209004

RESUMEN

BACKGROUND: Antiphospholipid (aPL) antibodies are associated with thrombosis in patients diagnosed with antiphospholipid syndrome (APS) and enhance thrombus formation in vivo in mice, but the mechanism of thrombosis by aPL is not completely understood. Although aPL antibodies have been shown to inhibit protein C activation and activate endothelial cells (ECs) in vitro, no study has examined whether these antibodies activate ECs in vivo. Therefore, human affinity-purified aPL (ap aPL) antibodies from APS patients were tested in a mouse model of microcirculation using the cremaster muscle that allows direct microscopic examination of thrombus formation and adhesion of white blood cells (WBCs) to ECs as an indication of EC activation in vivo. Adhesion molecule expression on human umbilical vein endothelial cells (HUVECs) after aPL exposure was performed to confirm EC activation in vitro. METHODS AND RESULTS: All 6 ap aPL antibodies significantly increased the expression of VCAM-1 (2.3- to 4.4-fold), with one of the antibodies also increasing the expression of E-selectin (1.6-fold) on HUVECs in vitro. In the in vivo experiments, each ap aPL antibody except for 1 preparation increased WBC sticking (mean number of WBCs ranged from 22.7 to 50.6) compared with control (14.4), which correlated with enhanced thrombus formation (mean thrombus size ranged from 1098 to 6476 versus 594 microm2 for control). CONCLUSIONS: Activation of ECs by aPL antibodies in vivo may create a prothrombotic state on ECs, which may be the first pathophysiological event of thrombosis in APS.


Asunto(s)
Anticuerpos Antifosfolípidos/farmacología , Síndrome Antifosfolípido/inmunología , Enfermedades Autoinmunes/inmunología , Endotelio Vascular/efectos de los fármacos , Trombofilia/etiología , Adulto , Animales , Anticuerpos Antifosfolípidos/inmunología , Especificidad de Anticuerpos , Síndrome Antifosfolípido/fisiopatología , Enfermedades Autoinmunes/fisiopatología , Adhesión Celular , Células Cultivadas , Relación Dosis-Respuesta Inmunológica , Selectina E/análisis , Endotelio Vascular/citología , Endotelio Vascular/fisiología , Femenino , Glicoproteínas/inmunología , Humanos , Inmunización Pasiva , Inmunoglobulina G/farmacología , Molécula 1 de Adhesión Intercelular/análisis , Inhibidor de Coagulación del Lupus/inmunología , Inhibidor de Coagulación del Lupus/farmacología , Masculino , Ratones , Microcirculación/efectos de los fármacos , Trombosis/etiología , Molécula 1 de Adhesión Celular Vascular/análisis , beta 2 Glicoproteína I
20.
J Surg Res ; 82(2): 268-74, 1999 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-10090839

RESUMEN

BACKGROUND: TNP-470 (AGM-1470) is a potent inhibitor of angiogenesis with potential therapeutic applications in neoplastic and angio-proliferative diseases. This study evaluated its effect on cutaneous wound healing in a murine dorsal excisional wound model. MATERIALS AND METHODS: Full-thickness wounds (1.60 cm2) were created on the dorsum of homozygous/hairless mice (7 to 9 weeks). Wound areas were measured on alternate days for 16 days. Experimental groups consisted of (1) TNP-470 administered in doses of 0.05, 0.5, and 5.0 mg/kg on Days 0, 2, and 4 or Days 0 through 6; (2) TNP-470 (5.0 mg/kg) coadministered with minocycline (4.0 and 10 mg/kg) on Days 0, 2, and 4; and (3) TNP-470 (5.0 mg/kg on Days 0, 2, and 4) coadministered with topical basic fibroblast growth factor (bFGF) 1. 0 microg/wound on Days 0, 1, and 2. Hematoxylin and eosin staining was used to compare experimental and control wounds. RESULTS: TNP-470 administration significantly decreased wound healing in a dose-dependent manner versus controls (P <.05). The 5.0 mg/kg concentration yielded the greatest effect by maintaining an average wound area 20.4% greater than controls and a marked delay in wound healing on H&E staining. Alternate-day dosing was as effective as consecutive day administration. Minocycline did not augment the wound healing inhibition of TNP-470. Coadministration of TNP-470 and bFGF eliminated any rate-altering effect of TNP-470 upon wound healing and resulted in wound areas similar to controls. CONCLUSION: Therapy with TNP-470 induces a significant delay in murine cutaneous wound healing. This effect may be exploited for use in situations where wound healing is excessive and debilitating. Topical application of bFGF can overcome TNP-470-induced wound healing inhibition.


Asunto(s)
Inhibidores de la Angiogénesis/farmacología , Sesquiterpenos/farmacología , Piel/lesiones , Cicatrización de Heridas/efectos de los fármacos , Heridas Penetrantes/fisiopatología , Animales , Antibacterianos/farmacología , Ciclohexanos , Combinación de Medicamentos , Factor 2 de Crecimiento de Fibroblastos/farmacología , Masculino , Ratones , Ratones Pelados , Minociclina/farmacología , O-(Cloroacetilcarbamoil) Fumagilol , Piel/patología , Heridas Penetrantes/patología
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