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Biomedical subjects

M Torres

Publications and source records attributed to M Torres.

At least 271 records · Page 15Linked to original sources
PubMed1989

99Tcm-MAG3 for quantitation of differential renal function.

We studied two different methods for the evaluation of differential renal function in a group of 100 patients with various kidney disorders whose effective renal plasma flow (ERPF) had been calculated previously by single 125I-orthoiodohippurate (OIH) injection and multiple blood sampling. Patients were divided into three groups according to their ERPF:ERPF is greater than or equal to 250 ml min-1; ERPF less than or equal to 100 ml min-1; and ERPF greater than 100 ml min-1 and less than 250 ml min-1. The two methods used to assess differential renal function were: first, relative 99Tcm-dimercaptosuccinic acid (DMSA) uptake calculated by normalized background and attenuation corrected cumulative counts in each kidney 24 h p.i.; and second, relative 99Tcm-mercaptoacetyl-triglycine (MAG3) uptake within 1 and 2 min p.i. calculated by normalized background and attenuation corrected counts on each renal area. The results obtained with each method correlated strongly with high significance (p less than 0.0001). In the right kidney, mean values obtained with 99Tcm-MAG3 tend to be higher than mean values obtained with 99Tcm-DMSA.

Adult↗
PubMed1989

Interovarian relationship in the secretion of progesterone during the luteal phase of the capuchin monkey (Cebus apella).

In basal conditions, progesterone concentrations were similar in the ovarian veins of the ovary +CL (3211 +/- 526 ng/ml) and the ovary -CL (3165 +/- 554 ng/ml), but after blocking the blood flow between the ovary +CL and the uterus, the progesterone values in the vein draining the ovary -CL decreased to 1218 +/- 394 ng/ml (P less than 0.01). When [3H]progesterone was injected in the ovary +CL, the radioactivity appeared earlier and more concentrated in the vein draining the ovary -CL (30 sec, 0.53% of injected dose) than in the femoral vein (150 sec, 0.08% of injected dose). Removal of the ovary +CL was followed by a brief maintenance of peripheral progesterone within luteal-phase levels. The in-vitro progesterone production by a suspension of cells isolated from the corpus luteum was 47.5 +/- 12.8 ng/ml/2 h, whereas luteal-like cells isolated from the ovary -CL secreted 14.3 +/- 6.0 ng/ml/2 h (P less than 0.01) into the medium. We therefore suggest that the symmetrical and high secretion rate of progesterone by the ovaries of the capuchin monkey indicates a between-ovary communication system, and that the luteal-like tissue of the ovary -CL can produce relatively large amounts of progesterone.

Animals↗
PubMed1989

Dopaminergic mediation of the diuretic and natriuretic action of centrally administered rat atrial natriuretic factor (99-126).

Intracerebroventricular administration of either rat atrial natriuretic factor (99-126) or dopamine to conscious male hydrated rats resulted in an increase in urinaryvolume and sodium excretion. This activity was prevented, in both cases, by nonselective dopamine antagonist haloperidol (2.5 or 1.25 mg/kg sc, 18 and 2 hr before intracerebroventricular administration of atrial natriuretic factor). Our findings suggest that atrial natriuretic factor exerts its centrally mediated effects on sodium and water metabolism, at least in part, via a dopaminergic mechanism.

Animals↗
PubMed1989

[Pulmonary infiltrates, eosinophilia and polyneuritis].

A case of chronic eosinophilic pneumonia which, during the evolution, developed a very rare motor-sensitive polyneuritis of the lower limbs, is presented. We comment on the results of the electromyography, the neuromuscular biopsy and show the differential diagnosis with other diseases with lung infiltrates, peripheric eosinophilia and polyneuritis, such as hypereosinophilic syndrome, allergic angiitis and granulomatosis of Churg and Strauss.

Adult↗
PubMed1989

[Massive pleural effusion secondary to hydronephrosis].

The most frequent causes of pleural effusion are congestive heart failure, advanced cirrhosis and nephrotic syndrome. In some rare cases urine can be found accumulated in the pleural compartment, being this entity denominated urinotorax. This phenomenon is generally considered secondary to an urinary obstruction or to an urinoma on the same side as the effusion through mechanisms not yet clarified. Given that it is a benign condition, easily resolved by clearing the obstruction of the urinary tract and that there is little information about it in the literature, we report a case of a massive pleural effusion secondary to hydronephrosis.

Aged↗
PubMed1989

[Transaxial tomography in the study of myocardial perfusion with thallium-201].

Stress and redistribution thallium-201 myocardial imaging using a transaxial single emission computed tomographic system has been applied to the diagnosis of coronary artery disease. Data sampling was performed along a limited 180 degree arc, obtaining 32 images in a continuous mode, at a rate of 20 seconds per image. The production of perfusion defects in patients was stimulated by exercise testing or by dipyridamole infusion. No significant differences existed when both tests were compared (p less than 0.01). Normal and abnormal patterns including the different pathophysiological alterations of myocardial ischemia were defined in three tomographic planes using this methodology. Patients with coronary disease are separated from patients without coronary disease with high probability (84%). Transaxial SPECT (single photon emission computerized tomography) provides a significant increment in sensitivity and specificity in relation to planar scintigraphy in the detection of myocardial infarction (91 and 100%, respectively); residual ischemia postinfarction (96 and 97%, respectively), and significant coronary artery disease (91 and 97%, respectively).

Adult↗
PubMed1988

Adenosine transporters in chromaffin cells: subcellular distribution and characterization.

Adenosine transporters in freshly isolated and cultured chromaffin cells were quantified by the [3H]dipyridamole binding technique, showing a maximal bound capacity of 0.4 +/- 0.05 pmol/10(6) cells (240,000 +/- 20,000 transporters by cell). Scatchard analysis showed a similar affinity for [3H]dipyridamole in isolated cells and subcellular fractions (Kd = 5 +/- 0.6 nM). For enriched plasma membrane preparations and chromaffin granule membranes, the maximal binding capacities were also very similar, 2.3 +/- 0.3 and 1.8 +/- 0.4 pmol/mg protein, respectively. When [3H]nitrobenzylthioinosine was employed as a radioligand, the maximal bound capacity in cultured chromaffin cells was 0.053 +/- 0.004 pmol/10(6) cells (32,000 +/- 3000 transporters per cell) with a high affinity constant (Kd = 0.25 +/- 0.03 nM); similar values were obtained in all subcellular fractions (Kd = 0.1 +/- 0.01). Also, plasma and chromaffin granule membranes showed similar maximal binding values (0.4 +/- 0.06 pmol/mg protein). Photoincorporation studies with [3H]nitrobenzylthioinosine into plasma membrane polypeptides showed the presence of three molecular species of 115 +/- 10; 58 +/- 6 and 42 +/- 5 kDa. Chromaffin granule membranes showed only the 105 +/- 9 and 51 +/- 4 molecular species.

Adrenal Medulla↗
PubMed1988

Glucose transporters in chromaffin cells: subcellular distribution and characterization.

The glucose transporter was identified and characterized by cytochalasin B binding in subcellular membrane fractions of chromaffin tissue. The binding was saturable with Kd of about 0.3 microM for each subcellular fraction. The Bmax capacity was 12-16 pmol/mg protein for enriched plasma membrane fractions, 6.3 pmol/mg protein for microsomal membrane preparations and 5.4 pmol/mg protein for chromaffin granule membranes. Irreversible photoaffinity labelling of the glucose-protectable binding sites with [3H]cytochalasin B followed by solubilization and polyacrylamide gel electrophoresis from enriched plasma membrane preparations demonstrated the presence of three molecular species: 97 +/- 10, 51.5 +/- 6 and 30 +/- 4 kDa. The chromaffin granule membranes showed only a molecular species of 80 +/- 10 kDa.

Adrenal Medulla↗
PubMed1988

Concurrent hypnogenic and reflex paroxysmal dystonia.

A 29-year-old patient with nocturnal episodes of paroxysmal dystonia is described. In addition, attacks could be provoked by stimulation of his right foot. Treatment with phenytoin resulted in a marked reduction in the frequency of the episodes.

Adult↗
PubMed1988

Randomized comparative study of therapeutic paracentesis with and without intravenous albumin in cirrhosis.

It has recently been shown that repeated large-volume paracentesis associated with intravenous albumin infusion is a rapid, effective, and safe therapy of ascites in cirrhosis. To investigate whether intravenous albumin infusion is necessary in the treatment of cirrhotics with large-volume paracentesis, 105 patients with tense ascites were randomly allocated into two groups. Fifty-two patients (group 1) were treated with paracentesis (4-6 L/day until disappearance of ascites) plus intravenous albumin infusion (40 g after each tap), and 53 (group 2) with paracentesis without albumin infusion. After disappearance of ascites, patients were discharged from the hospital with diuretics. Patients developing tense ascites during follow-up were treated according to their initial schedule. Paracentesis was effective in eliminating the ascites in 50 patients from group 1 and in 48 from group 2, with the duration of the hospital stay being approximately 11 days in both groups. Paracentesis plus intravenous albumin did not induce significant changes in standard renal function tests, plasma renin activity, and plasma aldosterone. In contrast, paracentesis without albumin was associated with a significant increase in blood urea nitrogen, a marked elevation in plasma renin activity and plasma aldosterone concentration, and a significant reduction in serum sodium concentration. One patient from group 1 and 11 from group 2 developed renal impairment or severe hyponatremia after treatment, or both (chi 2 = 9.19; p less than 0.01). The development of these complications could not be predicted by clinical and laboratory data before treatment. Although the probability of survival after entry into the study was similar in patients from both groups, a multivariate analysis identified the development of hyponatremia or renal impairment, or both, following the first paracentesis treatment and the occurrence of other complications during the first hospitalization (encephalopathy, gastrointestinal bleeding, and severe infection) as being the only independent predictors of mortality. These results indicate that intravenous albumin infusion is important in avoiding renal and electrolyte complications and activation of endogenous vasoactive systems in cirrhotics with ascites who are treated with repeated large-volume paracentesis. The development of such complications may impair survival in these patients.

Albumins↗
PubMed1988

Urine ethanol assessment: a helpful method for controlling abstinence in alcoholic liver disease.

The usefulness of a urine-alcohol determination in the evaluation of abstinence in alcoholic liver disease has been investigated in 181 patients. Alcohol was tested in morning urine samples collected on a follow-up visit in 103 patients, and the results were compared with those in 78 patients, where three samples were collected within the same week; one in the morning and two in the evening. Although the percentage of urine samples containing alcohol measured in a morning sample was similar to the patients' self-report (31% and 34%, respectively), urine analysis identified an additional 7% of patients who denied alcohol intake. Alternatively, serial urine-alcohol determinations were significantly more effective than patient reports (54% and 35.9%, respectively, P less than 0.01), particularly when urine was collected in the evenings. This difference was due mainly to the reluctance of women to admit drinking (7.4% of positive self reports vs 51% of women with alcohol positive urine samples, P less than 0.001). We conclude that serial measurements of alcohol in urine were useful tests which should be used to complement personal interview in the control of abstinence in patients with alcoholic liver disease.

Ethanol↗
PubMed1988

Subcellular distribution studies of diadenosine polyphosphates--Ap4A and Ap5A--in bovine adrenal medulla: presence in chromaffin granules.

Diadenosine tetraphosphate (Ap4A) and diadenosine pentaphosphate (Ap5A) have been identified in bovine adrenal medullary tissue using an HPLC method. The values obtained were 0.1 +/- 0.05 mumol/g of tissue for both compounds. The subcellular fraction where Ap4A and Ap5A were present in the highest concentration was chromaffin granules: 32 nmol/mg of protein for both compounds (approximately 6 mM intragranularly). This value was 30 times higher than in the cytosolic fraction. Enzymatic degradation of Ap4A and Ap5A, isolated from chromaffin granules, with phosphodiesterase produces AMP as the final product. The Ap4A and Ap5A obtained from this tissue were potent inhibitors of adenosine kinase. Their Ki values relative to adenosine were 0.3 and 2 microM for Ap4A and Ap5A, respectively. The cytosolic fraction also contains enzymatic activities that degrade Ap4A as well as Ap5A. These activities were measured by an HPLC method; the observed Km values were 10.5 +/- 0.5 and 13 +/- 1 microM for Ap4A and Ap5A, respectively.

Adenosine Diphosphate↗
PubMed1988

Natriuretic and diuretic action of centrally administered rat atrial natriuretic peptide (99-126): possible involvement of aldosterone and the sympathoadrenal system.

Intracerebroventricular (ICV) administration of rat atrial natriuretic peptide (99-126) (rANP) to conscious male hydrated rats resulted in a dose-related increase in urinary volume and sodium excretion over a 6-h period of urine collection. A diminished mineralocorticoid effect on the kidneys may explain the natriuretic phenomenon. This hypothesis was tested by ICV rANP injection (1.25 microgram/5 microL) in conscious hydrated rats pretreated beforehand with d-aldosterone (20 micrograms/kg, ip). Although the absolute amount of sodium excreted was reduced, aldosterone did not affect rANP-induced sodium output at 1 and 3 h. Rats that were sham-operated or bilaterally adrenalectomized after 4 days were pretreated with aldosterone and given an oral water load followed by ICV rANP or saline. The possible participation of the peripheral sympathetic nervous system in the central action of rANP was evaluated in rats pretreated with 6-hydroxydopamine. In sympathectomized and adrenalectomized rats natriuresis and diuresis were still evident after rANP. Our results indicate that the natriuretic effect of ICV rANP is independent of mineralocorticoids. Likewise, diuresis and natriuresis can occur in the absence of the adrenal glands and are independent from the neural tone that the adrenergic system exerts on sodium reabsorption.

Adrenal Glands↗
PubMed1988

The effects of daily exposure to UV-A light on phenylalanine ammonia-lyase activity during the growth of barley plants.

The activity of phenylalanine ammonia-lyase (PAL) during the life cycle of barley plants (Hordeum distichon L.) exposed to UV-A radiation (355 nm) during 15, 30 and 60 min day-1 was studied. In comparison with the control plants, a stimulatory effect on PAL activity was observed. This effect was directly related to the exposure time to UV-A radiation. It was also noted that the amount of protein extracted, decreased significantly with age increase in all treatments. The studied enzyme showed its highest activity during early stages of growth. A sharp and progressive decline in PAL activity was observed in older plants. This decrease was more evident during the development of the ear.

Ammonia-Lyases↗
PubMed1987

Pneumomediastinum, pneumothorax, and subcutaneous emphysema after alternate cocaine inhalation and marijuana smoking.

Previous reports have indicated the association of marijuana and cocaine abuse along with prolonged Valsalva maneuvers and the use of positive pressure devices. In most cases, the use of a single drug has been related to barotrauma. We present an adolescent male who developed this complication after alternate use of marijuana and cocaine without positive pressure devices. The increasing problem of drug abuse in the adolescent population in the United States is known to all of us. Clinicians who deal with adolescent patients should include questioning about drug abuse in the standard evaluation of chest pain.

Adolescent↗