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1.
J Bone Miner Res ; 13(3): 454-63, 1998 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-9525346

RESUMEN

1,25-dihydroxyvitamin D3 (1,25(OH)2D3) receptors (VDR) are expressed in multiple tissues within the body. VDR levels are increased by 1,25(OH)2D3 in intestine and kidney and in numerous cell models. The ability of 1,25(OH)2D3 to affect VDR levels in other target tissues in vivo was studied by assessing VDR levels by the 3H-1,25(OH)2D3 binding assay under varied physiological conditions in the rat. When compared with vitamin D-deficient (-D) controls, rats raised on a normal vitamin D-sufficient (+D) diet showed elevated VDR levels in kidney (391 +/- 53 vs. 913 +/- 76 fmol/g of tissue;p < 0.05), but not in testis, heart, or lung. Up-regulation of the VDR also occurred in kidney of +D rats 1 day after a single 100-ng dose of 1,25(OH)2D3 (454 +/- 43 vs. 746 +/- 113 fmol/mg of DNA; p < 0.05), but no changes were seen in intestine, testis, or lung. Because 1,25(OH)2D3-induced hypercalcemia may independently affect VDR regulation, 1,25(OH)2D3 was infused into -D rats, and normocalcemia was maintained by reduced dietary calcium intake. In this model, the renal VDR was again up-regulated (446 +/- 115 vs. 778 +/- 58 fmol/mg of DNA; p < 0.05), but VDR levels in testis and lung were unaffected. Scatchard analysis and tests of 1,25(OH)2D3 dose (1-100 ng/day for 7 days) and temporal (100 ng/day for 1-7 days) responsiveness further supported the tissue-specific nature of the homologous VDR regulation. Assay of VDR levels by L-1-tosylamido-2-phenylethyl chloromethyl ketone-3H-1,25(OH)2D3 exchange assay ruled out differences in endogenous 1,25(OH)2D3 occupancy as the basis for the observed differences in VDR regulation. Finally, coidentity of the VDR-like sites in kidney versus testis was confirmed by competitive binding analysis comparing their relative affinities for 25(OH)D3 versus 1,25(OH)2D3 (30.5 +/- 6.4 vs. 35.6 +/- 3.6 in kidney and testis, respectively) and by immunoblot analysis using a highly specific monoclonal anti-rat VDR antibody. Thus, under a wide variety of experimental conditions, homologous up-regulation of the VDR occurs in the rat kidney in vivo, but not in several other target tissues which do not regulate plasma calcium homeostasis. Moreover, this differential VDR regulation did not result from secondary changes in plasma calcium, from differential 1,25(OH)2D3 responsiveness in the various tissues, nor from differences in endogenous 1,25(OH)2D3 occupancy of the VDR. These studies thus establish that, in contrast to observations in vitro, the widely described phenomenon of homologous VDR up-regulation in kidney and intestine is not a universal property of 1,25(OH)2D3 target tissues in vivo in the rat.


Asunto(s)
Calcitriol/farmacología , Receptores de Calcitriol/metabolismo , Animales , Unión Competitiva , Relación Dosis-Respuesta a Droga , Reacciones Falso Negativas , Immunoblotting , Mucosa Intestinal/metabolismo , Riñón/metabolismo , Pulmón/metabolismo , Masculino , Ensayo de Unión Radioligante , Ratas , Ratas Sprague-Dawley , Receptores de Calcitriol/antagonistas & inhibidores , Estadística como Asunto , Testículo/metabolismo , Factores de Tiempo , Regulación hacia Arriba
2.
Am J Med Genet ; 63(3): 419-25, 1996 Jun 14.
Artículo en Inglés | MEDLINE | ID: mdl-8737645

RESUMEN

To identify, contact, and offer free cystic fibrosis (CF) carrier education, testing, and genetic counseling to the first, second, and third degree relatives of individuals with CF, study personnel contacted probands or the parents of minor probands requesting assistance in identifying relatives. We requested family pedigrees, including names, addresses, and phone numbers and if necessary a saliva sample for determination of the specific CF mutations in the family. Two hundred three families of 220 probands being followed at a large CF clinic in the Southeastern United States were eligible for inclusion in the study. Of the 203 families 109 (53.7%) assisted by providing contact information on relatives and, when necessary, a saliva sample for mutation analysis. An additional 33 (16.4%) agreed to assist but did not provide either or both contact information or saliva samples. Sixty-one (30.1%) declined to provide assistance. Thirteen percent of the probands/parents wanted to talk with relatives before providing contact information. A logistic regression model predicting proband/parent assistance is provided. This study suggests that the active outreach method used here to identify at risk relatives to offer them CF carrier testing resulted in somewhat lower proband or parent assistance than reported by other similar approaches. The strengths and weaknesses of this approach, including comments by probands and parents on the method, are discussed.


Asunto(s)
Fibrosis Quística/genética , Asesoramiento Genético/estadística & datos numéricos , Heterocigoto , Adolescente , Adulto , Actitud Frente a la Salud , Niño , Preescolar , Fibrosis Quística/diagnóstico , Fibrosis Quística/epidemiología , Análisis Mutacional de ADN , Femenino , Humanos , Lactante , Masculino , Modelos Teóricos , Análisis Multivariante , Linaje , Análisis de Regresión , Saliva/fisiología , Factores de Tiempo
3.
Behav Med ; 20(4): 171-8, 1995.
Artículo en Inglés | MEDLINE | ID: mdl-7620229

RESUMEN

The authors of the present study investigated the relationship between rheumatoid arthritis (RA) patients' demographic, medical, and functional status and caregivers' burden, optimism, and pessimism. Subjects were 65 RA patients and their caregivers who were recruited from an outpatient rheumatology clinic. Each caregiver completed the Burden Interview to measure caregiver burden and the Life Orientation Test to measure optimism and pessimism. Each RA patient completed the Arthritis Impact Measurement Scale to measure pain and physical disability as well as a number of cognitive measures to assess two summary psychological cognitive factors labeled self-efficacy expectations and distorted cognitions. These cognitive factors were based on the following commonly used measures in RA research: the Cognitive Errors Questionnaire, the Arthritis Self-Efficacy Scale, the Coping Strategies Questionnaire, and the Pain Beliefs and Perceptions Inventory. Correlational analyses indicated that patients' functional and psychological measures (including poor self-efficacy expectations regarding symptoms) were related to caregiver burden, that patient self-efficacy expectations were related to caregiver optimism, and that patient physical disability was related to caregiver pessimism. Regression analyses revealed that, when competing with other demographic and disease severity variables, the relationships between patient self-efficacy expectations and caregiver burden and caregiver optimism, and patient physical function and caregiver pessimism remained significant. Taken together, these findings suggest that patient expectancies about control over arthritis-related symptoms (including pain) are strongly related to caregiver burden and caregiver optimism and that patient physical status is strongly related to caregiver pessimism.


Asunto(s)
Artritis Reumatoide/psicología , Cuidadores/psicología , Costo de Enfermedad , Rol del Enfermo , Actividades Cotidianas/psicología , Adaptación Psicológica , Adulto , Anciano , Anciano de 80 o más Años , Humanos , Control Interno-Externo , Persona de Mediana Edad , Motivación , Determinación de la Personalidad , Autoimagen
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