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Biomedical subjects

M Uda

Publications and source records attributed to M Uda.

69 records · Page 4Linked to original sources
PubMed1981

Hypertension, hypokalemia and hypoaldosteronism with suppressed renin: a clinical study of a patient with Liddle's syndrome.

A 24-yr-old woman with hypertension, hypokalemic alkalosis, low plasma renin and hypoaldosteronism was studied. Plasma aldosterone, renin and potassium returned to normal and blood pressure fell after sodium restriction or the administration of triamterene. Thiazide therapy also normalized her blood pressure while dexamethasone, spironolactone and furosemide did not improve her symptoms. Plasma aldosterone levels were low and responded poorly to a short term ACTH injection, but responded well to the maximal adrenal stimulation by ACTH-Z. Plasma levels of cortisol, corticosterone and deoxycorticosterone were within the normal range. Adrenal scintigram with 131I-adosterol and abdominal computed axial tomography did not reveal the presence of a sizeable adrenal tumor. In addition, the urinary kallikrein excretion was low after sodium restriction and showed no response to saline infusion. These findings suggest that the excessive secretion of unusual mineralocorticoids may not exist in this case. From these observations and the results of the therapeutic responses to the diuretic agents, we conclude that the primary cause of the disorder of this patient seems to be a renal defect in the distal tubule in handling sodium and potassium which is similar to that in Liddle's syndrome.

Adrenocorticotropic Hormone↗
PubMed1978

Structural requirements of alkyl acyldithiocarbazates for the uncoupling of oxidative phosphorylation in mitochondria.

A structure-activity relationship study on the uncoupling of alkyl acyldithiocarbazates was carried out. Greater activity was observed with increasing alkyl chain length, the optimum being C9. A further increase in alkyl chain length caused a decrease in the activity. Thione-thiol tautomeric forms with a dissociable proton were dound to be of primary importance for the uncoupling and the role of the acyl group was auxiliary. The reactivity of the SH group of alkyl acyldithiocarbazates with an SH-reagent was very low. These compounds facilitated the valinomycin-induced swelling of non-respiring mitochondria and non-sonicated lecithin liposomes in isotonic potassium acetate solution.

Animals↗
PubMed1978

Syntheses and uncoupling activities of alkyl dithiocarbazates and alkyl pyridinecarbonyldithiocarbazates.

A series of alkyl dithiocarbazates, alkyl 3-picolinoyldithiocarbazates, alkyl 3-nicotinoyldithiocarbazates, alkyl 3-isonicotinoyldithiocarbazates, and alkyl 3-picolinoyl-2-methyldithiocarbazates was prepared. These alkyl pyridinecarbonyldithiocarbazates were shown to be uncouplers of oxidative phosphorylation in mitochondria. The finding that uncoupling activity increased with increase in the length of the alkyl chains of the compounds indicates that hydrophobicity influences the activity. The nonyl derivatives had the highest activity. The results also suggested that a dissociable acidic proton is necessary for the uncoupling activity.

Animals↗
PubMedDate not supplied

Optimal protocol for preparation of leukocyte-poor red cells with a blood cell processor.

The optimal red cell override (RCO) protocol for preparation of leukocyte-poor red cells (LPRCs) with a blood cell processor (IBM 2991) was studied. By a four-step process, including determining leukocyte (WBC) and red cell (RBC) distributions in the processing bag after centrifugation, the optimal RCO sequence was determined. The "effectiveness index" of WBC removal also was used for comparison of the efficiencies of various RCO protocols. In this way, a four-cycle RCO sequence of 1.5/1.5/1.5/1.5 was found to be optimal for washing 130-ml units of concentrated red cells (CRCs). This protocol yielded LPRCs with means of 5.4 percent of WBCs remaining and an 84.2 percent recovery of RBCs. The optimal RCO sequence of 2.0/2.0/2.0/2.0 for washing 260-ml units of CRC gave LPRCs with means of 6.2 percent of WBCs remaining and an 87.8 percent recovery of RBCs.

Blood Transfusion↗
PubMedDate not supplied

Preparation of blood components with saline-adenine-glucose-phosphate-maltose quadruple-pack system.

A saline-adenine-glucose-phosphate-maltose (SAGP-maltose) quadruple-pack system was devised to improve the conventional method of preparing blood components. One of the features of this method is that high-speed centrifugation was used as the initial spin in the two-step centrifugation of whole blood. This feature permitted the removal of the buffy coat from red cells at the same time the platelets were isolated. Since the platelets were concentrated without forming a button, the damage to the platelets due to mechanical stress in preparation was minimized. Another major feature was the use of the SAGP-maltose solution. Maltose effectively prevented hemolysis during storage in a protein-poor medium for preserving red cells. Judging from the red cell adenosine triphosphate level and morphology score, it should be possible to store red cells for 35 to 42 days in SAGP-maltose preservative. In addition, approximately 25 percent more plasma was collected in the present system than in conventional multiple-pack systems.

Blood Platelets↗
PubMedDate not supplied

Acute histological effects of interstitial hyperthermia on normal rat brain.

Histological changes in the brains of Fischer rats at different times after interstitial heating with various thermal doses were studied. The brains, subjected to sham-heating, and heating at 39 and 40 degrees C for 30 min showed mild capillary congestion and minimal vacuolation at 4, 24 and 72 h. In the brains heated to 41, 42 and 43 degrees C for 30 min, there was local vascular congestion, petechiae, vacuolation and cellular shrinkage with nuclear pyknosis at 4 h; enhanced congestion and petechiae, acute cellular necrosis, infiltration of polymorphonuclear leukocytes and marked vacuolation at the margin at 24h; total coagulative necrosis of all parenchymal and vascular elements, early liquefaction necrosis and vascular hyperplasia at the margin at 72 h; enhanced vascular hyperplasia at the margin at 120 h and 168 h. The threshold thermal dose for the histopathological damage in the rat brain was heating at 41 degrees C for 30 min.

Animals↗
PubMedDate not supplied

Role of intracellular calcium concentration on tumor cell death from hyperthermia.

The intracellular calcium ion concentration of SCK cells was measured after the cells were heated to determine the relationship between thermotolerance and intracellular calcium concentration. SCK cells, which are breast cancer cells that spontaneously arise in A/J mice, were used. Exponentially growing cells were trypsinized and incubated for 60 min with fura-2/AM at a concentration of 10 M. The incubation was carried out at a density of 1x106 cells/ml in serum-free RPMI medium. Thermotolerance was induced by incubating cells for 5 h at 37yC after heating them at 43yC for 30 min. When heated at 44yC in a calcium containing buffer, the intracellular calcium concentration of non-thermotolerant and thermotolerant cells increased continuously as the cells were heated for longer periods of time. The same increase in intracellular calcium concentration was seen in these two cell lines when heated at 43yC in a calcium-free buffer. Thus, our data indicated that intracellular calcium ion increased during heating due to an influx into the cytoplasm from both internal stores and the extracellular medium.

Animals↗
PubMedDate not supplied

Effects of right hemithoracic irradiation on ceftazidime penetration into the alveolar space in rats.

The effect of thoracic irradiation on antibiotic penetration into the alveolar space was determined in a hemithoracic irradiation rat model to evaluate radiation-induced acute alveolar injury at various time intervals. The results of this investigation may be summarized as follows: (1) The transfer of ceftazidime (CAZ: Modacin) from blood to lung tissue, that is, the permeability of pulmonary capillary epithelium, and the transfer of ceftazidime from lung tissue to bronchoalveolar lavage fluid, that is, the permeability of the alveolar epithelium, peaked at 4 to 5 weeks after thoracic irradiation; (2) the time course of change in the absolute concentration of ceftazidime in lung tissue showed a significant increase not only in the irradiated lung but also in the contralateral non-irradiated lung 3 days or more after irradiation. The finding that the administration of antibiotics may cause a significant increase in drug concentration in lung tissue even in the contralateral lung at 3 days after irradiation suggests that the change induced at the alveolar level immediately after irradiation affects the non-irradiated lung field through an as yet unknown mechanism.

Acute Disease↗