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1.
G Ital Dermatol Venereol ; 145(4): 433-44, 2010 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-20823788

RESUMEN

Perioral dermatitis presents as an eruption of erythematous papules, pustules and papulovesicles, most frequently seen in young women. Oral tetracyclines have been considered the first line treatment for years. However, recent publications have found newer agents to be efficacious. The authors performed a review of the available data in order to determine the strength of evidence supporting published therapies. A Pubmed and Cochrane Library database search for all cases, case series, and clinical trials dealing with the treatment of perioral dermatitis in English. Most cases of perioral dermatitis are self-limited, if the possible exacerbants of cosmetics and topical corticosteroids are discontinued ("zero therapy"). Many trials support the use of oral tetracyclines as a first line medication, as it significantly shortens the time to papule resolution. Topical erythromycin also reduces the time to resolution, but not as quickly. Topical pimecrolimus does not appear to decrease the time to complete resolution, but it does rapidly reduce the severity of the disease, particularly if prior corticosteroid use has occurred. The evidence supporting topical metronidazole, which is frequently used to treat perioral dermatitis in children, is relatively weak and supported only by case series and a trial showing it to be inferior to tetracycline. The evidence most strongly supports the efficacy of zero therapy, topical pimecrolimus, oral tetracycline, and topical erythromycin.


Asunto(s)
Dermatitis Perioral/tratamiento farmacológico , Medicina Basada en la Evidencia , Administración Tópica , Eritromicina/administración & dosificación , Humanos , Metronidazol/administración & dosificación , Tetraciclina/administración & dosificación
2.
AIDS ; 13(10): 1207-12, 1999 Jul 09.
Artículo en Inglés | MEDLINE | ID: mdl-10416524

RESUMEN

OBJECTIVE: To assess the efficacy of salvage therapy containing ritonavir and saquinavir after failure of indinavir- or nelfinavir-containing regimens, and to determine correlates of success or failure. DESIGN: Retrospective chart review. SETTING. The Moore Clinic - the HIV clinic of Johns Hopkins Hospital. PATIENTS: Forty-one HIV-infected patients were identified through physician contacts, referrals from other providers, and review of a comprehensive clinical database. MAIN OUTCOME MEASURES: To determine response to salvage therapy, HIV-1 viral RNA (absolute and log10-transformed) was measured using the Roche Amplicor quantitative HIV-1 RNA assay after initiation of the salvage regimen. Potential correlates of response included: viral RNA at the time of switch; viral RNA at the time of switch as a percentage of baseline viral RNA; magnitude of decline in viral RNA; and the interval between virologic failure of single protease inhibitor therapy and switch to the salvage regimen. RESULTS: Thirteen (56.5%) of 23 patients failing indinavir responded to salvage therapy (HIV RNA < 400 copies/ml) with persistence throughout the follow-up period (median of 37 weeks; range 18-67 weeks). Mean absolute viral RNA at the time of switch was 20 238 copies/ml (median, 9281) compared with 42 953 copies/ml (median, 24 650) for the 10 non-responders. Mean log10 viral RNA at switch was 3.804 for responders versus 4.405 for non-responders (P = 0.040). Among four responders who had failed nelfinavir, mean viral RNA was 9634 copies/ml and mean log10 viral RNA was 3.749 at the time of switch. Two non-responders had a mean viral RNA of 21 551 and a mean log10 viral RNA of 4.037 at switch. CONCLUSIONS: In contrast with previous reports, salvage regimens containing ritonavir and/or saquinavir can be effective and durable following the failure of combination regimens containing either indinavir or nelfinavir. Salvage therapy may be more likely to succeed when it is initiated early in failure at low viral loads.


Asunto(s)
Infecciones por VIH/tratamiento farmacológico , Inhibidores de la Proteasa del VIH/uso terapéutico , VIH-1/fisiología , Ritonavir/uso terapéutico , Saquinavir/uso terapéutico , Adulto , Fármacos Anti-VIH/uso terapéutico , Quimioterapia Combinada , Femenino , Infecciones por VIH/virología , Humanos , Indinavir/uso terapéutico , Masculino , Persona de Mediana Edad , Nelfinavir/uso terapéutico , ARN Viral/sangre , Estudios Retrospectivos , Terapia Recuperativa , Insuficiencia del Tratamiento , Carga Viral
3.
Sleep ; 5(2): 188-94, 1982.
Artículo en Inglés | MEDLINE | ID: mdl-7100747

RESUMEN

Two samples of dreams collected from college students in 1950 and 1980 under similar conditions were analyzed using some of the Hall-Van de Castle scales. It was found that there has been little change over a period of 30 years in what college students dream about. Moreover, the sex differences in the 1980 dreams are the same as those in the 1950 dreams.


Asunto(s)
Sueños , Estudiantes/psicología , Agresión , Femenino , Humanos , Relaciones Interpersonales , Masculino , Factores Sexuales
4.
Am J Med Genet ; 1(4): 407-16, 1978.
Artículo en Inglés | MEDLINE | ID: mdl-665726

RESUMEN

Serially subcultured fibroblast strains from genital (foreskin, labium majus) skin, as a group, have considerably more steroid (testosterone) 5alpha-reductase activity than those form nongenital skin. Foreskin strains varied 40-fold and labial strains even more. Labial strains overlapped nongenital strains of either sex more frequently than did prepuce strains. The activity of foreskin strains from two siblings with proven 5alpha-reductase deficiency was clearly lower than that of any of 18 control stains. The comparative behavior of the various strain types indicates that labial and nongenital strains should not be used to support a clinical suspicion of male pseudohermaphroditism due to 5alpha-reductase deficiency. The activities of labial strains from patients with complete androgen insensitivity (testicular feminization) - five with the receptor-negative variety and two with the receptor-positive type - were as variable as those of control labial strains. The decreased 5alpha-reductase activity observed in fresh skin slices of some patients is probably and expression of their functional estrogen/androgen imbalance in vivo.


Asunto(s)
3-Oxo-5-alfa-Esteroide 4-Deshidrogenasa/metabolismo , Trastornos del Desarrollo Sexual/enzimología , Genitales/enzimología , Oxidorreductasas/metabolismo , Piel/enzimología , 3-Oxo-5-alfa-Esteroide 4-Deshidrogenasa/deficiencia , Adulto , Síndrome de Resistencia Androgénica/diagnóstico , Síndrome de Resistencia Androgénica/enzimología , Trastornos del Desarrollo Sexual/diagnóstico , Femenino , Fibroblastos/enzimología , Humanos , Lactante , Masculino
5.
Invest Radiol ; 35(4): 227-34, 2000 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-10764091

RESUMEN

RATIONALE AND OBJECTIVES: Molecular imaging with targeted contrast agents enables tissues to be distinguished by detecting specific cell-surface receptors. In the present study, a ligand-targeted acoustic nanoparticle system is used to identify angioplasty-induced expression of tissue factor by smooth muscle cells within carotid arteries. METHODS: Pig carotid arteries were overstretched with balloon catheters, treated with tissue factor-targeted or a control nanoparticle system, and imaged with intravascular ultrasound before and after treatment. RESULTS: Tissue factor-targeted emulsions bound and increased the echogenicity and gray-scale levels of overstretched smooth muscle cells within the tunica media, versus no change in contralateral control arteries. Expression of stretch-induced tissue factor in carotid artery media was confirmed by immunohistochemistry. CONCLUSIONS: The potential for abnormal thrombogenicity of balloon-injured arteries, as reflected by smooth muscle expression of tissue factor, was imaged using a novel, targeted, nanoparticulate ultrasonic contrast agent.


Asunto(s)
Arterias Carótidas/diagnóstico por imagen , Músculo Liso Vascular/diagnóstico por imagen , Tromboplastina/análisis , Animales , Cateterismo , Medios de Contraste , Fluorocarburos , Microscopía Electrónica de Rastreo , Porcinos , Tromboplastina/metabolismo , Ultrasonografía
6.
Peptides ; 22(11): 1919-24, 2001 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-11754982

RESUMEN

Adrenomedullin (AM), a potent vasodilatory and hypotensive peptide produces several biological outcomes in glomerular mesangial cells. Mesangial cells are important in the pathogenesis of glomerulonephritis, and therefore the actions of AM on mesangial cells have important clinical and therapeutic implications. This minireview describes the various actions of AM on mesangial cell function and the signal transduction mechanisms involved. As in other systems, most actions of AM can be explained by increase in cAMP levels in the cell, although a few exceptions remain. The fact that most data obtained to date has been in culture, the physiological significance of the actions of AM in mesangial cells is discussed.


Asunto(s)
Mesangio Glomerular/efectos de los fármacos , Péptidos/farmacología , Adrenomedulina , Animales , Células Cultivadas , Predicción , Mesangio Glomerular/citología , Mesangio Glomerular/fisiología , Humanos , Transducción de Señal/efectos de los fármacos
7.
Eur J Pharmacol ; 388(2): 133-8, 2000 Jan 28.
Artículo en Inglés | MEDLINE | ID: mdl-10666504

RESUMEN

Adrenomedullin is a recently identified peptide hormone that has receptors in a number of different systems including renal mesangial cells. We reported recently that adrenomedullin can cause a decrease in extracellular signal-regulated kinase (ERK) activity and increase jun amino-terminal kinase (JNK) and P38 mitogen-activated protein kinase (P38 MAPK) acitivities in rat mesangial cells. Associated with these responses we also reported that adrenomedullin can decrease proliferation and increase apoptosis in mesangial cells. The major aim of the present study was to examine the mechanism of decrease in ERK activity by adrenomedullin and to identify the role of protein phosphatase 2A (PP2A) in the decrease in ERK activity, using okadaic acid [9,10-Deepithio-9,10-didehydroacanthifolicin], a selective inhibitor of PP2A at low nanomolar concentrations. The adrenomedullin-induced decrease in [3H]-thymidine incorporation and increase in apoptosis were reversed by okadaic acid at the concentration that selectively inhibits PP2A. Okadaic acid completely reversed the ERK inhibition caused by adrenomedullin, suggesting that PP2A may be involved in the adrenomedullin-mediated changes in proliferation, apoptosis and ERK activity. PP2A activity in mesangial cells was increased over time following exposure to adrenomedullin. The tyrosine phosphorylation of ERK did not change significantly following adrenomedullin treatment although the ERK activity was decreased significantly. This suggests that the decrease in ERK activity is not mediated through a decrease in MEK (a dual phosphorylating kinase upstream of ERK) or by an increase in MKP-1/2 (a dual specificity phosphatase) activities. Thus we conclude that the mechanism of adrenomedullin-induced decrease in ERK activity in rat mesangial cells is at least in part mediated by an increase in PP2A activity.


Asunto(s)
Mesangio Glomerular/enzimología , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Péptidos/farmacología , Fosfoproteínas Fosfatasas/metabolismo , Adrenomedulina , Animales , Apoptosis/efectos de los fármacos , Western Blotting , Proteínas Quinasas Dependientes de Calcio-Calmodulina/metabolismo , División Celular/efectos de los fármacos , Células Cultivadas , Inhibidores Enzimáticos/farmacología , Ensayo de Inmunoadsorción Enzimática , Mesangio Glomerular/citología , Mesangio Glomerular/efectos de los fármacos , Ácido Ocadaico/farmacología , Fosfoproteínas Fosfatasas/antagonistas & inhibidores , Fosforilación , Proteína Fosfatasa 2 , Ratas , Ratas Sprague-Dawley , Timidina/metabolismo , Tirosina/metabolismo , Proteínas Quinasas p38 Activadas por Mitógenos
8.
Eur J Pharmacol ; 425(2): 85-93, 2001 Aug 10.
Artículo en Inglés | MEDLINE | ID: mdl-11502273

RESUMEN

The immunosuppressants, cyclosporin A and tacrolimus (FK506) induce an increase in plasma levels of adenosine and mimic ischemic preconditioning. However, the mechanism of action of the two drugs on adenosine metabolism is not clear. Since inhibition of adenosine kinase promotes an increase in endogenous adenosine release, we tested a hypothesis that FK506 induces adenosine release via inhibition of adenosine kinase activity. In cultured endothelial cells, FK506 enhanced release of tracer adenosine and inhibited uptake of tracer adenosine. It also reduced adenosine kinase activity of the cell membrane fraction. In addition, FK506 does not inhibit membrane transport of tracer adenosine. These observations indicate that FK506 inhibits in situ adenosine kinase activity in endothelial cells. Other cell signaling inhibitors were found to inhibit adenosine uptake via inhibition of adenosine transport. In conclusion, FK506 promotes adenosine release from endothelial cells by a novel mechanism involving inhibition of adenosine kinase activity associated with the membrane.


Asunto(s)
Adenosina Quinasa/antagonistas & inhibidores , Adenosina/metabolismo , Inhibidores Enzimáticos/farmacología , Tacrolimus/farmacología , Adenosina Quinasa/metabolismo , Animales , Transporte Biológico/efectos de los fármacos , Células Cultivadas , Endotelio/efectos de los fármacos , Endotelio/metabolismo , Proteínas Quinasas Activadas por Mitógenos/antagonistas & inhibidores , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Ratas , Sirolimus/farmacología
9.
J Am Soc Echocardiogr ; 13(6): 608-14, 2000 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-10849515

RESUMEN

Molecular imaging permits tissues to be functionally characterized by identification of specific cell-surface receptors with targeted contrast agents. In our study, a ligand-targeted acoustic nanoparticle system was used to identify the angioplasty-induced expression of tissue factor by smooth muscle cells within the tunica media. Pig carotid arteries were overstretched bilaterally with balloon catheters, treated with a tissue factor-targeted or a control nanoparticle system, and imaged with intravascular ultrasound (20 MHz) before and after treatment. Carotid wall acoustic reflectivities were unaffected by overstretch injury. Tissue factor-targeted nanoemulsion bound and increased the echogenicity of smooth muscle cells expressing tissue factor within the tunica media. The targeted emulsion increased the arterial wall gray scale (99.4+/-14.5; P<.05) relative to pretreatment (41.8+/-11.1, P<0.05) and the control gray scale (pre-emulsion: 49.3+/-9.5; post-emulsion: 43.7+/-6.4; P<.05). The area of acoustic enhancement appeared to coincide with expression of induced tissue factor in the tunica media confirmed by immunohistochemistry. We have demonstrated that this novel nanoemulsion can infiltrate into arterial walls after balloon injury and localize the expression of overstretch-induced tissue factor within pig carotid arteries. Molecular imaging and quantification of complex, biochemical change, such as tissue factor expression after angioplasty, may prove to be a prognostically important predictor of subsequent restenosis.


Asunto(s)
Arterias Carótidas/diagnóstico por imagen , Medios de Contraste , Tromboplastina/metabolismo , Ultrasonografía Intervencional , Acústica , Animales , Arterias Carótidas/metabolismo , Aumento de la Imagen , Inmunohistoquímica , Ligandos , Pronóstico , Túnica Media/diagnóstico por imagen , Túnica Media/metabolismo
10.
J Am Soc Echocardiogr ; 10(5): 511-7, 1997 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-9203490

RESUMEN

Time-domain-based integrated backscatter values obtained with the use of acoustic densitometry (AD) were compared with values determined from a spectral-based analysis of the radio-frequency (RF) signals with a modified Hewlett-Packard Sonos 1500 imaging system. Integrated backscatter images of five specimens of bovine tendon were acquired in the AD acquisition mode, and the corresponding signals related to the backscattered RF were digitized for each angle of insonification as the specimens were rotated in 10-degree increments. The integrated backscatter images were analyzed with the AD analysis package, and the corresponding values determined from the RF power spectra were obtained from the digitized ultrasonic signals. Good agreement was found between the two methods over the entire range of measured values. The mean anisotropy in the measured integrated backscatter (mean +/- standard error) was found to be 27 +/- 2 dB for time-domain-based analysis and 25 +/- 2 dB for RF spectral-based analysis.


Asunto(s)
Ultrasonografía , Acústica , Animales , Anisotropía , Bovinos , Densitometría , Técnicas In Vitro , Tendones/diagnóstico por imagen , Ultrasonografía/instrumentación
11.
Steroids ; 29(3): 407-16, 1977 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-140479

RESUMEN

Adrenals obtained from human abortices at midpregnancy were kept under conditions of tissue culture and the production of cortisol and dehydroepiandrosterone sulfate (3beta-hydroxy-5-androsten-17-one, 3-sulfate; DHA-S) monitored by radioimmunoassays for up to 2 weeks. Basal production of dehydroepiandrosterone sulfate was considerably higher than that of cortisol. alpha1-24corticotrophin, alpha1-39corticotrophin, (a long acting porcine corticotrophin) at the concentration of 1 mU/ml of culture medium in both instances, and dibutyryl cyclic AMP (1mM) enhanced the production of both steroids some 3 to 30 times above control values. Medium harvested from homologous pituitary cultures had comparable corticotrophic activity. It is concluded that at midpregnancy the regulation of corticoidogenesis implies the existence of a corticotrophic factor either identical or closely related to ACTH.


Asunto(s)
Deshidroepiandrosterona/biosíntesis , Hidrocortisona/biosíntesis , Hipófisis/fisiología , Sistema Hipófiso-Suprarrenal/metabolismo , Femenino , Feto , Edad Gestacional , Humanos , Cinética , Técnicas de Cultivo de Órganos , Embarazo
12.
Steroids ; 30(4): 569-80, 1977 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-605461

RESUMEN

Monolayer cultures of human midterm and term placentae have been established following trypsin dispersion of placental minces. Maintenance of endocrine function was monitored by the concentrations of specific hormones in the culture media. At either gestational age the cultures 1) secret estradiol-17beta(1) and estrone (in a ratio of about 1:20) and aromatize 3H- or 14C-dehydroepiandrosterone sulfate and 14C-androstenedione, estrogen production being markedly enhanced by addition of dehydroepiandrosterone (10(-6)7) to the culture medium; 2) metabolize 3H-pregnenolone to progesterone and 14C-cortisol to cortisone; and 3) produce increasing amounts of chorionic gonadotropin and decreasing amounts of placental lactogen during the first week in culture. It is proposed that the model is highly suited to the study of factors affecting hormonogenesis by the human placenta whether they be of maternal or of fetal origin.


Asunto(s)
Técnicas de Cultivo , Hormonas/biosíntesis , Placenta/metabolismo , Gonadotropina Coriónica/metabolismo , Medios de Cultivo , Técnicas de Cultivo/métodos , Estrógenos/biosíntesis , Femenino , Humanos , Hidroxiesteroide Deshidrogenasas/metabolismo , Placenta/enzimología , Lactógeno Placentario/metabolismo , Embarazo , Primer Trimestre del Embarazo , Segundo Trimestre del Embarazo , Tercer Trimestre del Embarazo , Progesterona Reductasa/metabolismo
13.
Steroids ; 31(4): 557-72, 1978 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-208200

RESUMEN

Explants prepared from the neocortex and the fetal zone of the human fetal adrenal (gestational age 13 to 18weeks) were maintained under conditions of organ culture for 7 to 9 days during which time they were exposed to hACTH and various related peptides. Corticotrophic activity was monitored by the daily release of dehydroepiandrosterone sulfate (3beta-hydroxy-5-androsten-17-one, 3-sulfate; DHA-S) and cortisol as quantified by radioimmunoassay, hACTH (2.2 x 10(-9) - 2.2 x 10(-8)M) was the most active in sustaining steroidogenesis by both neocortical and fetocortical cells. alpha-MSH possessed similar properties but not at concentrations lower than 10(-6)M, whereas CLIP (4.4 x 10(-9) - 1.1 x 10(-7)M), the 18-39 C-terminal moiety of ACTH, was devoid of activity. Corticotrophic activity with respect to fetocortical explants appeared to be that of maintenance of function best illustrated by dehydroepiandrosterone sulfate biosynthesis, while enhancement of steroidogenesis was observed in the neocortex as manifested by cortisol release. Although not eliminating the possible existence of a specific fetal corticotrophin related to ACTH1-39, the data indicate that hACTH is capable of regulating steroidogenesis in the fetal zone which is primarily geared to the formation of dehydroepiandrosterone sulfate.


Asunto(s)
Corteza Suprarrenal/metabolismo , Hormona Adrenocorticotrópica/farmacología , Deshidroepiandrosterona/biosíntesis , Hidrocortisona/biosíntesis , Hipófisis/metabolismo , Corteza Suprarrenal/efectos de los fármacos , Femenino , Feto , Edad Gestacional , Humanos , Hormonas Estimuladoras de los Melanocitos/farmacología , Técnicas de Cultivo de Órganos , Hipófisis/efectos de los fármacos , Embarazo
14.
J Pers Soc Psychol ; 46(5): 1109-17, 1984 May.
Artículo en Inglés | MEDLINE | ID: mdl-6737207

RESUMEN

Males dream more often of males than females do. This sex difference was found in 29 comparisons of male and female dreams. It holds for children, adolescents, college students, and adults in all parts of the world; and for dreams collected in the laboratory, as well as dreams reported under nonlaboratory conditions. Various explanations for this ubiquitous sex difference are discussed.


Asunto(s)
Sueños , Adolescente , Adulto , Niño , Preescolar , Comparación Transcultural , Femenino , Humanos , Masculino , Persona de Mediana Edad , Factores Sexuales , Sueño REM , Estudiantes/psicología
15.
Ultrasound Med Biol ; 26(4): 613-20, 2000 May.
Artículo en Inglés | MEDLINE | ID: mdl-10856624

RESUMEN

Elastic arteries consist of three primary components: elastin fibers, extracellular collagen matrix and smooth muscle cells. However, the relative contribution of elastin and collagen fibers to overall ultrasonic scattering from an intact arterial wall is poorly understood. To define the principal source of extracellular scattering from the medial layer of elastic arteries, canine ascending aortas (n = 10) were excised, fixed and sectioned for insonification. Subsequently, aortic specimens were restudied after treatment to dissolve all tissue components except extracellular collagen matrix (n = 5) and elastin fibers (n = 5). Histological staining revealed very few elastin fibers and sparse intact collagen in collagen-isolated and elastin-isolated tissues, respectively. Integrated backscatter, attenuation and backscatter coefficients differentiated these two treated tissues. The backscatter coefficient for elastin-isolated tissue demonstrated a fivefold increase over collagen-isolated tissue, suggesting that elastin fibers represent a primary scattering component within elastic arteries, and the collagen fibers may provide a secondary component of scattering.


Asunto(s)
Aorta Torácica/diagnóstico por imagen , Espacio Extracelular/diagnóstico por imagen , Ultrasonografía/métodos , Animales , Aorta Torácica/fisiología , Aorta Torácica/ultraestructura , Colágeno/fisiología , Colágeno/ultraestructura , Perros , Elasticidad , Elastina/fisiología , Elastina/ultraestructura , Espacio Extracelular/fisiología , Procesamiento de Imagen Asistido por Computador , Microscopía Electrónica de Rastreo
16.
Ultrasound Med Biol ; 26(3): 375-84, 2000 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-10773367

RESUMEN

Myocardial edema has been associated with impaired ventricular compliance and diastolic filling. To determine the sensitivity of high-frequency (40 MHz) ultrasound to myocardial edema, we employed a model in which myocardial edema was induced by immersion of tissue in isotonic saline. The effect of freezing tissue on edema formation was also evaluated. Rat hearts were arrested at end-diastole and insonified fresh within 15 min of excision (n = 5) or following being frozen for 24 h and thawed (n = 4). Measurements of attenuation, backscatter, tissue thickness and speed of sound were performed at baseline and hourly for 4 h, and compared with direct measurements of myocardial edema. Fresh tissue demonstrated a greater propensity for the development of edema than frozen tissue. Integrated backscatter increased in both tissues, whereas the magnitude and slope of attenuation decreased as edema evolved. We conclude that high-frequency ultrasound sensitively detects myocardial edema, and we propose that the extension of these methods to clinical frequencies may prove useful for monitoring and treatment of cardiac edematous disease states.


Asunto(s)
Cardiomiopatías/diagnóstico por imagen , Edema/diagnóstico por imagen , Acústica , Animales , Técnicas In Vitro , Masculino , Microscopía , Miocardio/patología , Ratas , Ratas Sprague-Dawley , Ultrasonografía/métodos
17.
Ultrasound Med Biol ; 21(7): 853-60, 1995.
Artículo en Inglés | MEDLINE | ID: mdl-7491741

RESUMEN

The clinical use of angiotensin-converting enzyme (ACE) inhibitors now represents the standard of care for the treatment of chronic congestive heart failure. We utilized ultrasonic tissue characterization to define potentially salutary effects of treatment with ACE inhibitors on the material properties of the heart and its potential influence on cardiac remodeling at the cellular level. Ten 1-month-old cardiomyopathic (CM) Syrian hamsters were treated with captopril (2 g/L water ad libitum), and 10 CM and 5 normal hamsters were maintained untreated for 9 months. Hearts were excised, and backscattered radio-frequency data were acquired from 1200 independent sites from each specimen with a high-resolution 50-MHz acoustic microscope for calculation of integrated backscatter. Treatment with captopril elicited relative decreases in left ventricular (LV) wet weight, LV calcium concentration and integrated backscatter (IB) in treated as compared with untreated cardiomyopathic hearts without affecting LV collagen concentration. The IB from hearts of treated cardiomyopathic hamsters was significantly less in both grossly normal regions of myocardium (P < 0.02) and scar tissue regions (P = 0.0005) as compared with IB from hearts of untreated hamsters. The reduced integrated backscatter from hearts of treated cardiomyopathic hamsters indicates direct alterations in the material properties of cardiomyopathic hearts after captopril therapy. The lower IB from scar tissue in the treated animals was associated with decreased scar tissue calcification, which represents a novel therapeutic effect of captopril. This is the first report that delineates direct effects of ACE inhibitors on the material properties of both scar tissue and grossly normal myocardium at the cellular level in experimental dilated cardiomyopathy.(ABSTRACT TRUNCATED AT 250 WORDS)


Asunto(s)
Cardiomiopatía Dilatada/diagnóstico por imagen , Inhibidores de la Enzima Convertidora de Angiotensina/uso terapéutico , Animales , Calcio/análisis , Captopril/uso terapéutico , Cardiomiopatía Dilatada/tratamiento farmacológico , Cardiomiopatía Dilatada/metabolismo , Cardiomiopatía Dilatada/patología , Colágeno/análisis , Cricetinae , Ecocardiografía , Ventrículos Cardíacos/diagnóstico por imagen , Ventrículos Cardíacos/patología , Técnicas In Vitro , Masculino , Mesocricetus , Miocardio/química , Miocardio/patología
18.
Ultrasound Med Biol ; 27(5): 611-9, 2001 May.
Artículo en Inglés | MEDLINE | ID: mdl-11397525

RESUMEN

The cardiac aging process is accompanied by global mechanical dysfunction that reflects increased myocardial stiffness. Accordingly, age-related changes in microscopic material properties of myocardium were delineated with high-frequency ultrasound (US) (30 to 44 MHz) tissue characterization methods for aging Fischer 344 rats at 6 (adult), 18 (aged), and 24 (senescent) months of age. The excised lateral wall of the left ventricle of rats (n = 10 per group) was insonified with a 50-MHz acoustic microscope for determination of integrated backscatter, backscatter coefficient and attenuation coefficient. Histological and biochemical analyses for collagen content and cardiac myocyte diameter were performed. Collagen concentration increased progressively with age, with the greatest increments occurring from 6 to 18 months (38.0 +/- 6.3 to 53.0 +/- 7.1 mg/g dry wt), and leveling off at 24 months (60.0 +/- 7.4 mg/g dry wt). Tissue microscopic material properties also changed progressively from 6 to 24 months of age, as determined by US methods: integrated backscatter increased (-44.7 +/- 1.8 vs. -40.8 +/- 1.9 dB, p < 0.05), attenuation increased (47.1 +/- 5.9 to 65.3 +/- 7.8 dB/cm, p < 0.05), and the backscatter coefficient increased (0.73 +/- 0.16 x 10(-5) to 3.76 +/- 1.6 x 10(-5) cm(-1), p < 0.05), from 6 to 24 months of age in each case. Age-related alterations in indices of cardiac microscopic material properties were closely correlated with the changes in cardiac microstructure. Ultrasonic tissue characterization may prove to be a sensitive tool to monitor changes in the cardiac microstructure, such as increased collagen deposition, that occur within age-related diastolic dysfunction.


Asunto(s)
Envejecimiento/patología , Envejecimiento/fisiología , Insuficiencia Cardíaca/diagnóstico por imagen , Miocardio/citología , Animales , Modelos Animales de Enfermedad , Ecocardiografía , Insuficiencia Cardíaca/patología , Insuficiencia Cardíaca/fisiopatología , Masculino , Ondas de Radio , Ratas , Ratas Endogámicas F344 , Ratas Sprague-Dawley
19.
Artículo en Inglés | MEDLINE | ID: mdl-18238640

RESUMEN

The progressive increase in stiffening of the myocardium associated with the aging process and abetted by comorbid conditions such as diabetes may be linked to an excessive number of collagen cross links within the myocardial extra-cellular matrix. To determine whether ultrasound can delineate changes in the physical properties of heart tissue undergoing cross linking, the authors employed a model in which increased cross linking was induced by treating rat myocardial tissue with specific chemical fixatives. Rat hearts (n=5 each group) were arrested at end-diastole, insonified (30 to 50 MHz) fresh within a few minutes of excision in a phosphate buffered solution, placed in a fixative (10% formalin or 2.5% glutaraldehyde) and insonified at 30-minute intervals thereafter for 24 hours. Ultrasonic attenuation increased in tissues cross linked with formalin (maximal change: 27.2+/-3.4 dB/cm) and glutaraldehyde (maximal change: 40.2+/-5.6 dB/cm) over a 24-hour period. The frequency dependence of the attenuation coefficient increased as a function of the extent of collagen cross links in formalin (maximal change: 0.8+/-0.3 dB/cm-MHz) and glutaraldehyde (maximal change: 0.9+/-0.6 dB/cm-MHz). This study represents the first time that the precise time course of myocardial protein cross linking in situ has been characterized by using real time monitoring, and the physiologic effect has been delineated on microscopic material properties.

20.
Artículo en Inglés | MEDLINE | ID: mdl-18238519

RESUMEN

Targeted acoustic contrast agents are designed to enhance the sensitivity and specificity of ultrasonic diagnoses. We have previously developed a ligand targeted ultrasonic contrast system that is a lipid-encapsulated, liquid-perfluorocarbon emulsion. The emulsion particles are small (250 nm) and have inherently low echogenicity unless bound to a surface by a pretargeted ligand through avidin-biotin interactions. We have recently proposed a simple acoustic transmission line model that treats the emulsion particles as a thin layer over the targeted surface. In this model, the acoustic reflectivity of the sample increases for perfluorocarbons with smaller velocities of longitudinal sound or lower densities. In this study, we measure and report the velocity of longitudinal sound for 20 perfluorocarbons using a broadband phase spectroscopic approach for estimating phase velocities. Experimentally determined velocities ranged from 520+/-2 m/sec (perfluorohexane) to 705+/-5 m/s (perfluorodecalin). No measurable dispersion was observed over the useful bandwidth of 2 to 22 MHz. Increasing carbon backbone chain length and fluorine substitution with halogens of greater atomic weight increased the measured speed of sound. Our experimental data were consistent (R=0.87) with a published empirical model that predicts velocity as a function of molecular structure. These data provide a rational basis for optimizing targeted perfluorocarbon-based contrast agents and offer further insight into the physical mechanisms responsible for the observed enhancement of surface acoustic reflectivity.

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