Correlative imaging in a patient with necrotic adrenal pheochromocytoma.
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Adrenal Gland Neoplasms↗
Biomedical subjects
M Boykin
Publications and source records attributed to M Boykin.
Effects of chronic treatment with cadmium on ATPases, uptake of catecholamines, and lipid peroxidation in rat brain synaptosomes.
The chronic effects of cadmium on specific activities of oligomycin-sensitive (OS) and -insensitive Mg2+ ATPase, Na(+)-K+ ATPase, lipid peroxidation, and uptake of catecholamines in brain synaptosomes of rats treated daily for 2 or 4 months were studied. Cadmium significantly decreased the specific activities of OS-Mg2+ ATPase, Na(+)-K+ ATPase, and uptake of [3H]-dopamine (3H-DA) and [3H]norepinephrine (3H-NE) and increased the lipid peroxidation.
Animals↗
Enhanced sensitivity of heart cells to adenosine and up-regulation of receptor number after treatment of guinea pigs with theophylline.
Experiments were carried out in hearts from guinea pigs that were fed either the adenosine receptor antagonist theophylline (0.6 mg/ml) or no drug. The A1 adenosine receptor radioligand [125I]aminobenzyladenosine bound to a single affinity class of receptors in heart cell membranes from control animals with Bmax and KD of 18.3 +/- 1.0 fmol/mg protein and 3.7 +/- 0.6 nM, respectively (n = 8). Heart cell membranes from animals fed theophylline for 2, 7, and 14 days bound the radioligand with about the same affinity, but the number of binding sites was significantly increased (p less than 0.01) to 30.6 +/- 1.7 (n = 3), 30.0 +/- 0.8 (n = 3), and 27.3 +/- 2.9 (n = 4), respectively. Nearly identical results were obtained with membranes prepared from enzymatically dispersed ventricular myocytes. Fourteen days of theophylline treatment also produced a small increase (12%, p less than 0.01) in the number of binding sites in membranes derived from cerebral cortexes. Isolated ventricular myocytes prepared from animals fed no drug or theophylline for 7 days were used to determine the effect of adenosine on 20 nM isoproterenol-stimulated calcium current (ICa) measured by the whole-cell patch-clamp technique. Adenosine reduced isoproterenol-stimulated ICa without affecting the activation or inactivation kinetics of the current; ICa density was reduced less by 5 microM adenosine in cells from control (25 +/- 3 to 21 +/- 3 microA/microF) than in cells from theophylline-fed animals (26 +/- 5 to 17 +/- 2 microA/microF). Although a high concentration (0.5 mM) of adenosine abolished isoproterenol-stimulated ICa in cells from control or theophylline-fed animals, the IC50 for adenosine was sixfold less in cells derived from theophylline-fed animals than in cells from control animals (4.6 +/- 0.6 microM and 28.3 +/- 1.4 microM, respectively, p less than 0.01). In contrast, the increase in ICa in response to isoproterenol alone and the potency of acetylcholine to antagonize this effect of isoproterenol were the same in both groups of cells. A maximally effective concentration of R-phenylisopropyladenosine (0.1 mM) inhibited isoproterenol-stimulated cyclic AMP accumulation less in cardiomyocytes from control than from theophylline-fed animals (28.7 +/- 1.8% vs. 42.0 +/- 4.2%, p less than 0.05). In summary, exposure of the myocardium to theophylline increases the number of adenosine receptors and the effects of receptor occupancy by agonists. These findings imply that the endogenous concentration of adenosine is high enough in the normoxic guinea pig heart to chronically maintain adenosine receptors in a partially down-regulated state.
Acetylcholine↗
Plasma adenosine and hypoxemia in patients with sleep apnea.
Severe hypoxemia causes ATP depletion and increased adenosine production in many body tissues. Therefore we hypothesized that patients with sleep apnea and severe hypoxemia during sleep have higher adenosine production and higher plasma adenosine levels than patients without hypoxemia. Twelve patients with sleep apnea and six normal volunteers had plasma adenosine levels measured by high-performance liquid chromatography. Each patient with sleep apnea had a polysomnograph sleep study with oxyhemoglobin saturation continuously recorded. Five of 12 patients with sleep apnea had both sleep apnea and severe hypoxemia during sleep. These patients with severe nocturnal hypoxemia had significantly higher plasma adenosine levels (means +/- SD 9.7 +/- 5.5 X 10(-8) M) than either a group of six normal volunteers (3.5 +/- 0.7 X 10(-8) M) or a group of seven patients with sleep apnea without hypoxemia at night (3.1 +/- 1.5 X 10(-8) M) (P less than 0.01). In addition plasma adenosine levels were significantly correlated with two indexes of nocturnal hypoxemia (desaturation index rs = 0.79, and median oxyhemoglobin saturation during sleep rs = -0.75, P less than 0.01). Plasma adenosine markedly fell to a normal level in the only two patients with sleep apnea who had successful treatment of their multiple apneas and accompanying severe hypoxemia during sleep.
Adenosine↗
The last surviving wall.
A total of 66 patients with advanced coronary artery disease (CAD) and 36 with dilated cardiomyopathies (DCM) with ejection fractions less than 20% were analyzed retrospectively to establish patterns of wall motion in each of four quadrants on standard left anterior oblique gated radionuclide ventriculograms. In both disease states the best preserved wall motion was found in the basal free wall quadrant of the left ventricle. The two terminal disease states could not be differentiated on the basis of wall motion patterns.
Cardiomyopathy, Dilated↗
"Halo" sign on indium-111 leukocyte scan in gangrenous cholecystitis.
A 56-year-old man with a long history of Crohn's disease was evaluated by In-111 labeled leukocyte scanning. A "halo" of leukocyte activity was seen around the gallbladder fossa. A gangrenous gallbladder was removed at surgery.
Cholecystitis↗
Effect of intraperitoneally injected cadmium on renal and hepatic gluconeogenic enzymes in rats.
Male Sprague-Dawley rats were injected intraperitoneally with 0, 0.25, 0.75 and 1.25 mg/kg/day for 14 days. At the end of 7 and 14 days treatment period, body weight gain, serum protein, serum glucose, serum glutamic oxaloacetic transaminase (SGOT) and serum glutamic pyruvic transaminase (SGPT) were measured. Glucose-6-phosphatase (G6-Pase), fructose-1, 6-di-phosphatase (FD-Pase), phosphoenol pyruvate carboxykinase (PEPCK) and pyruvate carboxylase (PC) in kidney and liver were determined. A significant decrease in body weight gain in rats treated with 1.25 mg cadmium for 7 and 14 days was observed. Serum glucose, serum protein, SGOT and SGPT were increased in cadmium treated rats. A significant increase in all four key gluconeogenic enzymes were observed in both kidney and liver tissues of rats treated with cadmium. The results of this study suggest that cadmium induces gluconeogenesis which is dose and time dependent.
Alanine Transaminase↗