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Biomedical subjects

T Asakura

Publications and source records attributed to T Asakura.

At least 307 records · Page 17Linked to original sources
PubMed1987

Decreased dopamine level in the epileptic focus.

Catecholamine and serotonin in the focus tissues of 12 intractable epileptic patients who underwent surgery were analysed by high performance liquid chromatography with electrochemical detection, and it was found that dopamine contents in epileptic foci were clearly lower than in surrounding tissue in 7 of the 12 epileptics examined. In the other 5 patients, dopamine levels were much lower than in non-convulsive neuropathic patients.

Adolescent↗
PubMed1987

Formation of light irreversibly sickled cells during deoxygenation-oxygenation cycles.

Changes in density, morphology, and monovalent cation content of sickle (SS) cells caused by repetitive sickling were investigated in vitro with a device by which red cells can be exposed to cycles of deoxygenation and oxygenation (d-o cycles). Experiments were done using the discocyte-rich, less dense fractions of SS cells. When such cells were subjected to d-o cycles in the presence of 2 mmol/L Ca2+, most became dense within 4 hours. The density of these cells was slightly lower than usual for irreversibly sickled cells (ISCs), and because they reverted to the discoidal shape after oxygenation, they were not considered ISCs. However, on further d-o incubation, they did assume the morphology and density typical of ISCs. After an additional incubation (20 hours), most cells decreased in density, became very fragile, and hemolyzed easily. Such light ISCs could also be formed from freshly prepared dense cells on d-o incubation. Once light ISCs were formed, they did not reconvert to dense cells on further incubation. It should be noted that light ISCs created in vitro tended to aggregate much more easily than ordinary (heavy) ISCs did, suggesting that the membrane of these cells may be very adhesive.

Anemia, Sickle Cell↗
PubMed1986

Demonstration of intermediates between deoxy and carbonmonoxy hemoglobins by anaerobic high-performance liquid chromatography.

Intermediary ferrous hemoglobins (Hb) partially liganded with carbon monoxide (CO) were separated using an anaerobic high-performance liquid chromatography system equipped with a cation-exchange column at room temperature. Separations were achieved by applying various mixtures of oxy- and CO-Hb A to the column. The mobile phase contained 3 mM sodium dithionite which deoxygenated the oxy hemes but left the CO hemes intact, thereby producing hemoglobins bound with various numbers of CO molecules. Spectrophotometric analyses of the eluent showed that hemoglobins were eluted in the order of deoxy hemoglobin, Hb(CO), Hb(CO)2 Hb(CO)3 and Hb(CO)4.

Carboxyhemoglobin↗
PubMed1986

Separation of asymmetrical hybrid containing hemoglobin F by anaerobic anion-exchange high-performance liquid chromatography.

Asymmetrical hybrid hemoglobins formed from mixtures of oxyhemoglobins S and F and A and F were separated by high-performance liquid chromatography on a 4.6 X 250 mm wide-pore polyethyleneimine-silica gel column under anaerobic conditions. The resulting HPLC chromatogram showed three peaks, with the middle peak representing the hybrid hemoglobin. The areas of these three peaks were quantified and the amount of hybrids formed was less than that predicted theoretically. We found that the deviation was due to the equilibrium constant of the FS hybrid hemoglobin differing from that of the parent hemoglobins. In this report, we introduce the anaerobic recycle ion-exchange HPLC method to determine the rate of dissociation of AS and FS hybrid hemoglobins at constant pH buffer conditions. The results obtained by this method demonstrate that FS hybrid hemoglobin is more unstable than AS hybrid hemoglobin. The free energy of association for asymmetrical hybrids containing hemoglobin F is approximately 0.6 Kcal/mol greater than that of the symmetrical parent hemoglobins.

Anaerobiosis↗
PubMed1986

Autosomal recessive inherited phosphofructokinase deficiency in English springer spaniel dogs.

Three families of English springer spaniel dogs with phosphofructokinase (PFK) deficiency causing haemolysis were studied. Four male dogs and one female dog with chronic haemolysis and haemolytic crises were found to have markedly reduced PFK activity in erythrocytes (8-20% of control English springer spaniels). PFK-deficient erythrocytes exhibited an extreme alkaline and sucrose lysis. The oxygen dissociation curve of erythrocyte suspensions was shifted to the left with a 50% saturation of haemoglobin at a partial oxygen pressure of 16-17 mmHg (normal 26-31 mmHg). Muscle wasting and mildly increased serum creatine phosphokinase activity were also noted. Six clinically normal first degree relatives of affected dogs had erythrocyte PFK activities that were 38-51% of controls. In these family members, there was an erythrocytosis and mild reticulocytosis probably due to a mildly enhanced haemoglobin-oxygen affinity but no increase in serum creatine phosphokinase. These studies confirm the familial nature of muscle-type PFK deficiency in English springer spaniels and support the conclusion that this animal model of the human glycogen storage disease type VII is inherited as an autosomal recessive trait.

Animals↗
PubMed1986

[Immunohistochemical studies of fetal and maternal endocrine pancreases during pregnancy and the puerperium in streptozotocin-induced diabetic rats].

In order to clarify the influence of the diabetic state on the structure of maternal and fetal endocrine pancreases, the distribution of alpha, beta and delta cells in the islets of Langerhans (IL) was investigated by PAP methods in normal and streptozotocin (STZ)-induced diabetic rats. The size of the IL significantly increased during pregnancy and on day 14 of puerperium in normal and diabetic maternal rats. The total cell numbers of IL also increased during pregnancy but decreased in puerperium in both groups. Although the number of beta cells was reduced in STZ-treated rats, they could increase during pregnancy as in the normal group. The number of beta cells kept increasing in puerperium in the diabetic group, but not in the normal group. The number of alpha and delta cells in diabetic rats was greater than in normal rats but did not change remarkably during pregnancy and in puerperium. The IL of fetuses from diabetic mothers were slightly greater in size and number than those from normal mothers. The number of fetal beta cells from normal mothers was somewhat greater than that from diabetic mothers. The number of fetal alpha and delta cells from diabetic mothers was slightly greater than that from normal mothers. These findings, therefore, suggest that diabetic IL could adapt themselves to pregnancy-induced metabolic changes.

Animals↗
PubMed1986

Importance of oxygenation in the appearance of acute subarachnoid hemorrhage on high field magnetic resonance imaging.

The ability to detect acute hemorrhage by magnetic resonance (MR) is related to the oxygen saturation of hemoglobin. This experiment measured the relaxation times of solutions of cerebrospinal fluid containing a 5 per cent hematocrit at various pO2's on a 1.4 tesla (T) MR imaging system. The results demonstrate that the state of oxygen saturation of hemoglobin determines the extent of T2 relaxation at this field strength. The T2 relaxation rate varies quadratically with the concentration of deoxyhemoglobin. There were no significant changes in the T1 relaxation rate with variations in pO2. These findings may, in part, explain the inability of MR to detect subarachnoid hemorrhage, and the MR appearance of blood in intratumoral hemorrhage, hemorrhagic cortical infarction and neonatal hemorrhage.

Acute Disease↗