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Biomedical subjects

T Asano

Publications and source records attributed to T Asano.

At least 901 records · Page 50Linked to original sources
PubMed1979

Increase of serum high density lipoprotein with progression and regression of aortic lipid deposition in rats.

The progression and regression of aortic lipid deposition was studied in male ExHC rats. Rats in the progression group were fed an atherogenic diet containing 2% cholesterol, 0.4% sodium cholate and 10% olive oil for periods up to 32 weeks. Rats in the regression group were first fed the atherogenic diet for 16 weeks, and then maintained on a basal low cholesterol diet. Half the rats were killed at 4 weeks and the other half at 16 weeks after cessation of the atherogenic diet. Rat aortas of the progression group contained progressively more lipid pari passu with the duration of cholesterol feeding, but connective-tissue proliferation was absent. Deposited lipid in the aorta of cholesterol-fed rats disappeared very slowly after the rats were returned to the basal diet. serum HDL decreased in the hypercholesterolemic ExHC rats fed the atherogenic diet for 4 weeks. By contrast, serum HDL and apo A-I increased in both hypercholesterolemic ExHC rats fed the atherogenic diet for 32 weeks and slightly hypercholesterolemic ExHC rats fed the basal diet for 16 weeks in the regression period.

Animals↗
PubMed1979

Identification of inosine and hypoxanthine as endogenous ligands for the brain benzodiazepine-binding sites.

Two endogenous ligands for the brain benzodiazepine-binding sites were isolated from bovine brain through gel filtration, paper electrophoresis, and paper chromatography. These ligands were identified as inosine and hypoxanthine, and both had a higher affinity for the brain benzodiazepine-binding sites than for benzodiazepine sites in some peripheral tissues. They did not bind to any other receptors tested, such as the opiate, muscarinic cholinergic, gamma-aminobutyric acid, and beta-adrenergic receptors. Both inosine and hypoxanthine competitively inhibited the binding of [3H]diazepam to the brain binding site.

Animals↗
PubMed1979

Induction of unresponsiveness to major transplantable organs in adult mammals: a recapitulation of ontogeny by irradiation and bone marrow replacement.

Transplantation of renal allografts obtained from prospectively selected genotypically DLA-identical donors into supralethally irradiated dogs reconstituted with their own stored bone marrow has produced a state of unresponsiveness to these kidneys in the recipients. Eleven of 18 kidneys transplanted at 12 hours after marrow replacement currently survive with normal function and maintain life in the recipients for 757, 800, 825, 978, 1062, 1092, 1136, 1282, 1373, 1380, and 1381 days, respectively. Similar results occurred in eight of 13 allografts transplanted at 28 hours after marrow replacement, which currently survive for 349, 363, 377, 407,436,470, 485, and 513 days, respectively, and in eight of 13 kidneys grafted at 36 hours after marrow replacement, which are surviving for 197, 247, 298, 324, 337, 396, 443, and 472 days, respectively. Achievement of optimal results is dependent on the specific timing and sequence of each procedure. Only four of 16 recipients of kidneys transplanted at the time of marrow replacement were unresponsive to their allografts. Similarly, only five of 19 recipients of kidneys placed in irradiated dogs at 40 hours before marrow replacement accepted such allografts. When kidney transplants were placed into the recipients 20 hours before removal of marrow, irradiation, and reconstitution with stored marrow, only three of 21 dogs became unresponsive to such ailografts. In five of 12 instances, the recipients were also unresponsive to skin allografts obtained from their respective kidney donors. Such skin grafts currently survive for 606, 673, 687, 701, and 708 days, respectively. The remaining seven skin grafts were rejected at 28, 39,42, 84, 90, 92, and 115 days, respectively. Second- and third-set skin grafts from the same kidney donor were rejected by six of these dogs at 19, 20, 21, 29, 29, and 30 days, and at 21, 22, 23, 24, 27, and 27 days, respectively. Rejection of these skin grafts had no detectable effect on the function and survival of kidney allografts from the same source. Seven of eight skin grafts obtained from other DLA-identical donors were rejected at 13,14,16,25,28,38, and 84 days, respectively; one allograft continues to survive for 708 days. Eleven DLA-incompatible skin allografts placed on the recipients at the same time were rejected within 11-20 days. Supralethal total body irradiation and bone marrow replacement can establish in the adult canine host a privileged phase of immunological reactivity during which exposure to alloantigens produces specific long-term unresponsiveness rather than sensitization. The use of stored autologous rather than allogeneic bone marrow for reconstitution of the irradiated recipient eliminates the hazards of GVH complication usually associated with this procedure. This consideration and the apparent capacity of the tolerant host to maintain a long-term state of unresponsiveness without any further immunosuppressive therapy point to the potential relevance of the results to human transplantation.

Animals↗
PubMed1978

Platelet aggregation and cyclic nucleotide phosphodiesterase activity in arteriosclerotic patients.

Although roles of roles of cyclic AMP and cyclic GMP in platelets are though to be important on platelet aggregation, little information on their phosphodiesterase (PDE) is available. Cyclic AMP and cyclic GMP hydrolytic activities of platelets (cAMPPDE and cGMPPDE in platelets) and platelet aggregation by ADP and adrenaline were measured in 22 healthy volunteers, 26 arteriosclerotic patients and other 20 miscellaneous patients excluding vascular diseases. Activities of cAMPPDE and cGMPPDE of platelets were 2.37 +/- 0.52, 7.23 +/- 1.84 in the healthy, 2.50 +/- 0.85, 7.53 +/- 2.60 in the arteriosclerotics and 2.38 +/- 1.02, 6.98 +/- 2.59 pmol/min/10(7) platelets in the miscellaneous patients, respectively. No significant difference was observed among these three groups. Platelet aggregabilities also showed no significant difference. However, there was a significant inverse correlation between the aggregability by 1 microgram/ml of adrenaline and the PDE activities only in the arteriosclerotic patients. The correlation coefficient were-0.61 between the primary aggregation and cAMPPDE,-0.65 between the primary aggregation and cGMPPDE,-0.58 between the 5 min aggregation and cAMPPDE and -0.76 between the 5 min aggregation and cGMPPDE. The inverse correlation between platelet aggregation and cyclic nucleotide metabolism in circulating platelts of the arteriosclerotic patients may suggest that interaction of platelets with arteriosclerotiv vessel walls would produce a certain change in platelets.

2',3'-Cyclic-Nucleotide Phosphodiesterases↗
PubMed1978

Characterisation of the effect of intravenous infusion of glucose and tolbutamide on the insulin delivery rate in man.

Serum insulin response to a single bolus of IV glucose or tolbutamide was measured in eight healthy subjects. Insulin disappearance rate was assessed by deconvolution from the serum insulin levels, using the measured insulin disappearance rate. The mean rate constant of insulin disappearance was 0.238 +/- 0.005 min-1 (mean +/- SEM). Basal insulin delivery rate was 8.0 to 9.0 mU/min and the delivery rate following glucose injection (0.5 g/kg body weight) showed a biphasic response, whereas that after tolbutamide injection (15.6 mg/kg body weight), a monophasic response. After glucose injection, 1.7 +/- 0.3 U of insulin was delivered during the first phase (0--10 min) and 5.6 +/- 1.6 U during the second phase (11--60 min). After tolbutamide injection, 1.5 +/- 0.3 U of insulin was delivered during the first 10 min. Between 11 and 40 min, 1.6 +/- 0.5 U of insulin was delivered. The results thus confirm and also quantitate biphasic insulin secretion after a bolus of glucose with a monophasic response after tolbutamide. The method is suitable for studies of the insulin secretogogues in man.

Glucose↗
PubMed1978

Insulin delivery rate in response to glucose infusion in normal and diabetic subjects.

The insulin delivery rates were estimated in 8 normal and 8 diabetic subjects from the results of peripheral insulin response to a single bolus iv injection of glucose, taking account of fractionally removed insulin. The delivered insulin response to 0.5 g/Kg body weight of glucose injection was biphasic in normal and diabetic subjects. In normal subjects, 1.7 +/- 0.3 U of insulin was delivered during the first phase (0-10 min) and 5.6 +/- 1.6 U during the second phase (11-60 min). In diabetic subjects, 0.4 +/- 0.2 U of insulin was delivered during the first phase and 1.8 +/- 0.5 U during the second phase. The amounts of delivered insulin during the first and second phases were significantly decreased in diabetics (p less than 0.01). The insulin delivery rates during the first and second phases fitted by the same line to the glucose concentration at each period. This suggests that a common glucoreceptor or glucose-mediated signal of the insulin response might exist during both phases. The glucose-insulin response curves in mild diabetics seemed to be similar to those in the normals, but shifted toward higher glucose levels. This finding suggests that the decreased glucose sensitivity of pancreatic beta cells in mild diabetics can be corrected by high glucose concentrations.

Adult↗
PubMed1978

[Measurement of cerebral blood flow with hydrogen clearance method: technique and a comparative study with the venous out flow method (author's transl)].

Local cerebral blood flow was measured with hydrogen clearance method in fifteen dogs and compared to direct measurement obtained by Michenfelder's venous out flow method. The sagittal sinus was exposed by a midline frontooccipital incision and extensive craniectomy. A tappered catheter was passed in to the superior sagittal. sinus. For measuring hydrogen clearance, platinum wire electrodes with a red tip of 0.5 mm in length and 0.3 mm in diameter were introduced into the parietal and occipital cortex. About ten percent hydrogen gas was given directly into the endotracheal tube for three to five minutes and the obtained clearance curves were transferred to semilog graph papers. Total cerebral blood flow was caliculated by bicompartmental analysis and compared to the two minutes initial slop index. The results are as follows. 1) A linear regression analysis of flows caliculated from the initial slope and bicompartmental analysis shows a high correlation coefficient. 2) There is a high correlation between flows caliculated from electrodes used at the same experiments. 3) Cerebral blood flow from the initial slope measured by hydrogen clearance method shows a high correlation wit flows caliculated from Michenfelder's venous out flow method.

Animals↗
PubMed1978

[Measurement of spinal cord blood flow in rabbits: central gray matter flow and CO2 reactivity (author's transl)].

Spinal cord blood flow (SCBF) was measured in 20 rabbits anesthetized with sodium pentobarbital. The platinum electrodes (0.3 mm in diameter) were inserted into the central gray matter of the thoracic spinal cord (Th8-10). In all animals, blood pressure and pAO2 remained constantly in the normal range. The pACO2 was changed by ventilation. Blood gases were checked both before and after each spinal cord blood flow measurement. The results are as follows. 1. Seventy-three percent of the clearances recorded from the gray matter were monoexponential and in the white matter almost all were monoexponential. 2. The mean values of gray matter SCBF of all animals was 38.3 +/- 1.85 ml/100 g/min (SE) at normo-capnea and the white matter was 19.5 +/- 1.33 ml/100 g/min. 3. An almost linear relationship exists between the pACO2 and SCBF. The values were 0.62 ml/100 g/min/torr in the gray matter and 0.38 ml/100 g/min/torr in the white matter.

Animals↗