RESUMEN
Scatchard analysis of (3H)CGP-12177 and (125I)cyanopindolol (CYP) radioligand binding data revealed the presence of specific beta-adrenergic receptor-binding sites on microdissected mouse proximal straight and medullary thick ascending limb (mTAL) tubules. beta-Receptor (10(-6) M isoproterenol) stimulation of isolated perfused mTAL tubules produced a consistent hyperpolarization of the transepithelial potential that was blocked by propranolol (10(-6) M), a beta-receptor antagonist, and furosemide (10(-4) M), an inhibitor of the Na+/K+/2 Cl- triporter. In contrast, there was no electrogenic response to isoproterenol stimulation in isolated perfused proximal straight tubules. In summary, radioligand binding data show that both proximal straight and mTAL tubules possess beta-receptor-binding sites. Electrogenic transport in the mTAL can be modulated by beta-agonists, but there was no detectable electrogenic response to beta-receptor stimulation in proximal straight tubules.
Asunto(s)
Isoproterenol/farmacología , Túbulos Renales/efectos de los fármacos , Antagonistas Adrenérgicos beta/metabolismo , Animales , Electrofisiología , Furosemida/farmacología , Técnicas In Vitro , Médula Renal/efectos de los fármacos , Médula Renal/metabolismo , Túbulos Renales/metabolismo , Túbulos Renales Proximales/efectos de los fármacos , Túbulos Renales Proximales/metabolismo , Cinética , Potenciales de la Membrana/efectos de los fármacos , Ratones , Perfusión , Pindolol/análogos & derivados , Pindolol/metabolismo , Propanolaminas/metabolismo , Propranolol/farmacología , Ensayo de Unión Radioligante , Receptores Adrenérgicos beta/efectos de los fármacos , Receptores Adrenérgicos beta/metabolismoRESUMEN
Over the past nine years (from 1981 to 1989), four patients with perianal Paget's disease were treated. All were male with an average age of 58.5 years. Clinically, perianal Paget's disease manifests as a slowly enlarging eczematous, and sharply demarcated perianal skin rash that may be oozing or itching. In the characteristic pathology finding, Paget's cells appear as large, rounded signet-ring cells with abundant mucin stain positive cytoplasm in the basal layer of the acanthotic epidermis. All but one, who suffered from primary sweat gland carcinoma, had underlying rectal adenocarcinoma. The first two cases expired soon after a delayed diagnosis of terminal underlying malignancy. Only in the later two cases was there a preoperative suspicion of perianal Paget's disease. There is often a delay in diagnosis due to clinical ignorance. Patients with persisting perianal skin rash should be biopsied frequently. If perianal Paget's disease is diagnosed, the underlying malignancy should be surveyed and managed thoroughly.