[Cost-benefit of the Schilling test using cobalt-57]. / Costo-beneficio de la prueba de Schilling con cobalto-57.

Our purpose in the present publication is to determine the cost-benefit relation of the Schilling test used to measure the intestinal absorption of radioactive vitamin B12. The 60Co-B12 urinary excretion Schilling test was first reported in 1953, and five years later it was being performed at the National Institute of Nutrition (INNSZ) in Mexico City. It was performed in its original version until 1969 and from 1970 to 1980, the direct absorption was measured with a whole-body counter. For the last nine years we have used the Schilling test with 57Co labeled cyanocobalamin. From January 1981 through March 1990, 240 of these tests were carried out in 120 patients. The results were tabulated and compared with their clinical diagnosis. We analyzed our laboratory and labor costs. An oral dose of 0.5 micrograms of vitamin B12 labelled with 18.5 Bq of 57Co is taken by the fasting patients and two hours later one mg of standard B12 vitamin is injected. Urine is collected for 48 hours and the radioactivity is measured in a scintillation counter. Three days later the test is repeated with an additional oral dose of intrinsic factor (IF). The total expense is calculated using the following factors: the cost of the imported radioactive vitamin, IF capsules, parenteral B12 vitamin, syringes, equipment use and its depreciation, laboratory material, and salaries for the professional and administrative personnel.(ABSTRACT TRUNCATED AT 250 WORDS)

The pharmacokinetic characteristics of a hepatobiliary 99mTc-radiopharmaceutical: comparison of the imported and national kits.

In nuclear medicine, the search for the perfect hepatobiliary agent started in 1955 with the rose bengal dye labeled with 131I. With the advent of technetium-99m, many ligands were labeled and Tc-99m-PG and 99mTc-HIDA were among the best suited for this purpose. Both were synthesized at the radiopharmacy laboratory during 1977-1980 and have been used at INNSZ for clinical studies. For the last three years, a new ligand with a bromine atom and an extra methyl radical has been reported as being one of the best third generation HIDAs. We received the gift of several kits of trimethyl-Br-IDA from Sorin Biomedica, Italy, (A) and of Mebrofenin from ININ, Mexico, (B) to be labeled and tested in order to select one of them for clinical work. For a comparative study on the radiopharmacodynamic characteristics of the two labeled ligands, six healthy women volunteered to undergo two tests with a 72 hour hour rest period to assure complete washout. After the I.V. dose of 111 MBq (3 mCi) the dynamic study was started and a total of 127 16-second images were acquired with a Siemens Digitrac 750 scintillation camera coupled to a Scintiview computer. Static images were taken at the end of the dynamic study and after breakfast. Blood and urine samples were collected for 24 hours and the amount of radioactivity was measured with a well type scintillation detector. The radiopharmacokinetic results are listed in tables 1-4.(ABSTRACT TRUNCATED AT 250 WORDS)

Absence of left ventricular hypertrophy in thyrotoxic patients without congestive heart failure. An echocardiographic study.

La masa ventricular izquierda (MVI), fue determinada por ecocardiografia modo M en 34 pacientes con tirotoxicosis sin insuficiencia cardiaca y en 82 pacientes con enfemedades en donde la hipertrofia ventricular izquierda ocurre con frecuencia (acromegalia, hipertension arterial sistemica, insuficiencia renal cronica y obesidad). Los valores de la MVI fueron comparados con los obtenidos en 30 sujetos normales. Se encontro que la MVI, fue anormal en pacientes con acromegalia, hipertension arterial con tirotoxicosis sin insuficiencia cardiaca. Esta es la serie mas grande de pacientes con tirotoxicosis estudiados mediante ecocardiografia y nuestros resultados cuestionan las conclusiones de otros estudios con menor numero de pacientes

Polysomnographic effects of thyroid hormones primary myxedema.

Nine primary myxedematous patients were subjected to all-night polysomnographic recordings under the following conditions: (1) basal or myxedematous state; (2) acute replacement therapy (treatment with thyroid hormones at doses that increased weekly to the maximal replacement dose, Mrd); and (3) chronic replacement therapy (maintenance on the Mrd; euthyroid state). The most striking abnormality found in the sleep pattern during the myxedematous state was observed in both young adult (greater than 20 years old) and adult (greater than 50 years old) patients, consisting of either a complete absence or very low levels of slow wave sleep (SWS). Replacement therapy was accompanied by a restoration of the normal sleep pattern in 3 of the 4 patients that were followed. In contrast, younger patients (14-18 years old with a bone age of less than or equal to 10 years) had normal levels of SWS, with the exception of an adolescent with a bone age of less than 3 years. The latency for rapid eye movement (REM) sleep tended to increase during acute replacement therapy and became normal when euthyroidism was reached. These results lend support to the proposal that thyroid hormones exert central effects on the adult CNS.