Age-related changes in adenosine in rat coronary resistance vessels.

1. The vasodilator effects of adenosine receptor agonists, isoprenaline and histamine were examined in perfused heart preparations from young (4-6 weeks) and mature (12-20 weeks) rats. 2. Adenosine induced a biphasic concentration-dependent decrease in KCl (35 mM) raised coronary perfusion pressure in hearts from young and mature rats, suggesting the presence of both high- and low-affinity sites for adenosine receptors in the two age groups tested. In heart preparations from mature rats, vasodilator responses to adenosine were significantly reduced compared with responses observed in young rats. 3. Responses to 5'-N-ethylcarboxamidoadenosine (NECA) and 2-p-(2-carboxyethyl)phenethylamino-5'-N-ethylcarboxamidoadenosine hydrochloride (CGS-21680) were reduced in preparations from mature rats, whereas the vasodilator actions of N6-cyclopentyladenosine (CPA) and N6-2-(4-aminophenyl)ethyladenosine (APNEA) did not change with age. 4. The results presented in this study suggest that several adenosine receptor subtypes mediate vasodilator responses in the coronary circulation of the rat and that a reduction in response to adenosine with age may be due to changes in the high-affinity receptor site.

A method to evaluate the response of the coronary circulation of perfused rat heart to adenosine.

Exogenous adenosine causes a monophasic dilation of the coronary vessels in paced, perfused rat heart preparations. Because levels of endogenous adenosine in paced hearts may mask the presence of high potency adenosine receptors, we have developed a method to measure coronary vascular responses in a potassium-arrested heart. Hearts from adult male, Wistar rats were perfused at a constant flow rate of 10 mL/min in the nonrecirculating, Langendorff mode, using Krebs-Henseleit buffer. After 30 min, coronary perfusion pressure was 44 +/- 1 mmHg (mean +/- SEM). Hearts were then perfused with a modified Krebs-Henseleit buffer containing 35 mM potassium. Coronary perfusion pressure increased by 84 +/- 3 mmHg. Adenosine-induced reductions in coronary perfusion pressure were expressed as a percentage of the maximal increase in pressure produced by modified Krebs-Henseleit buffer from the equilibration level. A concentration-response curve for adenosine (n = 6) was biphasic and best described by the presence of two adenosine receptors, with negative log EC50 values of 8.8 +/- 0.3 and 4.3 +/- 0.1, representing 29 +/- 3 and 71 +/- 3%, respectively, of the observed response. Interstitial adenosine sampled by microdialysis during potassium arrest was 25% of the concentration found in paced hearts. Endogenous adenosine in nonarrested hearts may obscure the biphasic response of the coronary vessels to adenosine.

[Photon-emission tomography (SPECT) in the detection of hepatic hemangiomas of small size]. / Contribución de la tomografía de emisión de fotones (SPECT) en la detección de hemangiomas hepáticos de pequeño tamaño.

By means of ultrasonography it is possible to detect hepatic lesions of few millimeters, however, it doesn't give a precise diagnosis. The role of planar scintigraphy in the diagnosis of hepatic hemangioma has already been established, although it has limitations which are partially solved by means of SPECT. 46 patients with different pathologies and 9 healthy volunteers have been studied. In the 19 confirmed hemangiomas, planar scintigraphy showed a sensitivity of 73.6% versus 84.2% for SPECT, mostly due to lesions less than 2.5 cm. Besides that, SPECT allowed a correct visualization of abdominal and intrahepatic major vessels, although lesions less than 1.5 cm are difficult to evaluate.

[Effectiveness of maintenance treatment with cimetidine in duodenal ulcer. Variations depending on the risk group]. / Eficacia del tratamiento de mantenimiento con cimetidina en el ulcus duodenal. Variaciones según el grupo de riesgo.

One hundred and twenty-two patients with confirmed duodenal ulcer were treated with cimetidine during 6 or 12 weeks. After gastroscopic confirmation of healing, treatment was suppressed during 3 months. Patients were randomized into two therapeutic regimens: intermittent according to recurrence of symptoms and maintenance with 400 mg cimetidine. In patients considered as having mild disease (healing at 6 weeks without recurrence) fared better with maintenance therapy than with intermittent dosage. All patients with moderate to severe disease on intermittent therapy had a recurrence (criterion: more than 6 weeks for healing the ulcer or recurrence before three months). Those on maintenance therapy had the following results: no recurrences 28%, one recurrence 56% and more than one 16%. Ninety three patients were followed during one entire year. There was also a statistical difference in the number of severe complications among patients on continuous maintenance (nil) and those on intermittent therapy (8%, p less than 0.05).

Urticaria pigmentosa. Histaminuria and treatment.

We present the case of an adult patient with urticaria pigmentosa. The sudden presence of severe symptomatology (symptoms to mast cell mediators release), made us think of evaluating extracutaneous affection. Our results are consistent with recent reports in the medical literature. We have confirmed an increase of conjugated histamine levels (methyl-histamine) during the attack and its return to normal values after the treatment. For these reasons we comment on the importance of histamine levels in diagnosis and treatment control. The gastrointestinal biopsy suggestive of mastocytosis; the severe clinical manifestations, and the histamine metabolite levels during the clinical course, led us to include this case in the group of "indolent SMCD" according to the TRAVIS classification.

[Cirrhosis caused by thorotrast: apropos of a case]. / Cirrosis por thorotrast: a propósito de un caso.

We present the clinical case of a female patient with cirrhosis of the liver. The radiografic and histopathological studies demonstrated that de etiology of this cirrhosis was in relation with the use of thorotrast given during angiografic studies which the patient underwent 35 years ago.