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Biomedical subjects

J A Rodriguez

Publications and source records attributed to J A Rodriguez.

116 records · Page 7Linked to original sources
PubMedDate not supplied

Adrenal macrotumors diagnosed by computed tomography.

UNLABELLED: Adrenal tumors larger than 6 cm are unusual but show a greater incidence of malignant etiologies than smaller adrenal tumors. The scarce information about adrenal macrotumors (AMT) induced us to study prospectively all patients who were seen in our clinic during the period 1984-1988 and were diagnosed by computed tomography (CT) to have an adrenal mass greater than or equal to 6 cm. The clinical characteristics, including the main complaint, tumoral secretory activity, CT findings and histologic diagnosis from 18 patients are described; they represented a 0.3% of the total amount of abdominal CT studies performed. Seventy-two % of AMT resulted to be non cortisol or catecholamines secreting masses, and from them, a 38% corresponded to malignant etiologies characterized by marked and rapid weight loss. Four out of five hormone secreting AMT corresponded to pheochromocytomas, while the fifth one resulted to be a bilateral macronodular hyperplasia secreting cortisol. In two cases AMT did not correspond to a genuine adrenal mass, resulting to be a malignant histocytoma in one case and a hydatidic cyst in other one. When performed in two occasions, a percutaneous needle biopsy was a valuable diagnostic tool, permitting to diagnose a lymphoma and a tuberculoma. IN CONCLUSION: 1) AMT correspond mainly to non cortisol or catecholamines secreting tumors, often malignant; 2) not all AMT diagnosed by CT correspond to true adrenal masses; 3) percutaneous needle biopsy can be a helpful procedure for diagnosing nonfunctioning solid AMT.

Adrenal Gland Neoplasms↗
PubMedDate not supplied

Renin-secreting tumor. Case report.

Renin-secreting tumor, though rare, should be considered in assessing severe hyperreninemic, hypertensive patients. We studied an 18-year-old girl with hypokalemic hyperreninemic hyperaldosteronism. No angiographic lesion could be detected. The plasma renin activity (PRA) of the right/left renal vein was 7.3. With a presumptive diagnosis of renin-secreting tumor (RST), the patient was operated on, and a cortical nodule was found on the right lower pole. Partial nephrectomy was followed by a rapid fall in PRA (half-life, 33-44 min) and normalization of blood pressure (BP). At 3 1/2 months postoperatively, the patient showed normotension, normokalemia, normal aldosterone, and slightly elevated PRA unresponsive to postural changes and furosemide treatment. Tumoral PRA secretion responded to postural stimulus, spironolactone use, and nitroprusside-induced hypotension. Neither the high aldosterone excretion nor hyperreninemia decreased after 3 days of DOCA; this agrees with a previously reported case suggesting the usefulness of this test in the diagnosis of RST.

Adolescent↗
PubMedDate not supplied

Enantioselective binding of albendazole sulphoxide to cytosolic proteins from helminth parasites.

The pharmacological effect of the active albendazole metabolite, albendazole sulphoxide (ABZSO), depends on its sustained presence at the site of parasite location and its binding to helmith beta-tubulin. ABZSO is found in the plasma and tissues of albendazole-treated animals in two enantiomeric forms: (+)ABZSO and (-)ABZSO. Knowledge of enantioselectivity in drug action is necessary, since any difference in target proteins affinity between enantiomers may have implications on the pharmacological effect of this anthelmintic molecule. The binding of ABZSO to mammalian and helminth parasites cytosolic proteins, as well as the differential binding of both enantiomers, were studied. Cytosolic proteins from Moniezia expansa (cestode), Ascaris suum (nematode), Fasciola hepatica (trematode), rat liver and brain as well as purified porcine brain tubulin were used. Drug analysis was performed by HPLC using both C18 and chiral columns. ABZSO protein binding was quantitatively different between parasite species (4.17, 2.5 and 1.07 ng/mg for cestode, nematode and trematode, respectively); this binding to helminth cytosolic proteins was enantioselective. Enantiomeric ratios of (-)ABZSO/(+)ABZSO as a percentage were: 43/57 (Ascaris), 36/64 (Moniezia) and 91/9 (Fasciola). Conversely, the binding of ABZSO to mammalian cytosolic proteins showed no enantioselectivity. The overall binding affinity of ABZSO for mammalian cytosolic proteins was lower than that observed in helminth proteins. The characterization of the comparative binding pattern of ABZSO enantiomers to cytosolic proteins from helminth parasites and mammalian tissues may contribute to understanding the pharmacological properties of this chiral anthelmintic molecule.

Albendazole↗
PubMedDate not supplied

Gps mutations in Chilean patients harboring growth hormone-secreting pituitary tumors.

Hypersecretion of GH is usually caused by a pituitary adenoma and about 40% of these tumors exhibit missense gsp mutations in Arg201 or Gln227 of the Gs, gene. We studied 20 pituitary tumors obtained from patients with GH hypersecretion. One tumor was resected from an 11 year-old boy with a 3 year history of accelerated growth, associated with increased concentrations of serum GH and IGF-I, which were not suppressed by glucose administration. The remaining 19 tumors were obtained from adult acromegalic patients, who had elevated baseline serum GH levels that did not show evidence of suppression after administration of glucose. The gsp mutations were studied by enzymatic digestion of the amplified PCR fragment of exon 8 (Arg201) and exon 9 (Gln227) with the enzymes NlaIII and NgoAIV, respectively. The tumors obtained from the boy and from nine of the 19 patients with acromegaly exhibited the gsp mutation R201H. None of the tumors had the Gln227 mutation. The gsp positive patients tended to be older, had smaller tumors, and had preoperative basal serum GH levels which were significantly lower (21 +/- 6 vs 56 +/- 16 microg/l, p<0.05) than the gsp negative patients. In this study, we documented the presence of a gsp mutation in Arg201 in a boy with gigantism and in approximately half of 19 Chilean adult patients with acromegaly, similar to other populations.

Adenoma↗