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Biomedical subjects

T Sakurada

Publications and source records attributed to T Sakurada.

At least 289 records · Page 16Linked to original sources
PubMed1982

Serum free thyroxine and triiodothyronine concentrations in subacute thyroiditis.

Serum absolute free T4 (AFT4) and T3 (AFT3) concentrations were studied in 10 patients with subacute thyroiditis whose total serum T4 levels were elevated, and values were compared with those obtained in 10 patients with untreated Graves' disease, whose total serum T4 concentrations were elevated to the same level as in the former group. The mean (+/- SD) basal metabolic rate in patients with subacute thyroiditis was 16 +/- 14.8%, significantly (P less than 0.001) lower than that in patients with Graves' disease (48.7 +/- 15.7%). Serum T4-binding globulin concentrations measured by RIA were normal and did not differ from those in Graves' disease patients. The percentage of free T4 and AFT4 were both elevated in subacute thyroiditis to a degree comparable to that seen in Graves' disease. The serum total T3, serum free T3 fraction and AFT3 were also elevated, but both total T3 and AFT3 were significantly (P less than 0.05 and P less than 0.05, respectively) lower than in Graves' disease patients. Therefore, the ratios of T3 to T4 and AFT3 to AFT4 were significantly (P less than 0.01 and P less than 0.01, respectively) lower than in Graves' disease patients. These results indicate that the significantly lower basal metabolic rate and milder manifestations of thyrotoxic symptoms in subacute thyroiditis than in Graves' disease might be explained by the low ratios of T3 to T4 and AFT3 to AFT4 as well as the short duration of chemical hyperthyroidism.

Alpha-Globulins↗
PubMed1982

Effects of morphine on single unit activity of the amygdala in cats.

Single neuronal activity has been recorded extra-cellularly from the nucleus amygdaloideus centralis (pars lateralis) (Acl), the nucleus amygdaloideus centralis (pars medialis) (Acm), the nucleus amygdaloideus basalis (pars magnocellularis) (Abm), the nucleus amygdaloideus lateralis (Al), and the nucleus amygdaloideus basalis (pars parvocellularis) (Abp). The majority of the Acl, Acm, and Abm neurons were excited by nociceptive stimulation such as pinching the skin with serrated forceps and/or intraarterial injection of bradykinin. The nociceptive neurons were also driven by non-nociceptive stimulation such as tapping of deep tissues and bending hairs with an air-puff. Their receptive fields were large. After the intravenous administration of morphine, all nociceptive neurons became unresponsive to nociceptive stimuli, although they were driven by non-nociceptive stimuli. Intravenous naloxone antagonized the antinociceptive action of morphine. This suggests that morphine has selective and inhibitory effects on impulse transmission to these nociceptive neurons, and the amygdala, especially the Acl, Acm, and Abm, plays an important role in central nociceptive processing.

Amygdala↗
PubMed1981

Purification and properties of CTP synthetase from Ehrlich ascites tumor cells.

CTP synthetase (UTP: ammonia ligase (ADP-forming), EC 6.3.4.2) was purified 200-fold from Ehrlich ascites tumor cells with about 50% purity as judged by polyacrylamide gel electrophoresis. The molecular weight estimated to be 118 000 by gel filtration. The optimal pH was 8.6. 2-Mercaptoethanol was required for optimal activity and stabilization of the enzyme. Magnesium was essential for the reaction and other divalent cations were ineffective. Ammonia could replace glutamine as the amino donor. When other substrates were at saturating concentrations, Michaelis-Menten kinetics were observed yielding Km values for UTP, ATP and glutamine of 0.18, 0.8 and 0.13 mM, respectively. With ATP at subsaturating concentration, the double-reciprocal plot for UTP saturation was sinusoidal and the Hill plot showed an n value of 1.3. The double-reciprocal plot for ATP saturation, when UTP was at subsaturating concentration, departed from Michaelis-Menten kinetics with an n value of 1.4. These data suggest the existence of cooperative interactions between enzyme and substrates at subsaturating concentrations of ATP or UTP. GTP was not essential, but it acted as an activator on the glutamine reaction; optimal activation was observed at 1 mM GTP. The affinity for glutamine was not affected by GTP.

Amino Acids↗
PubMed1981

Subcellular localization and some properties of monoacylglycerol lipase in rat adipocytes.

1. The subcellular localization of monoacylglycerol lipase in rat adipocytes was studied. The enzyme activities were mainly found in the plasma membrane and in the cytosol fraction. 2. The properties of the monoacylglycerol lipase activities, from both subcellular sites, were almost identical, except for slight differences in thermostability. 3. It is conceivable that there may be two kinds of monoacylglycerol lipases in adipose tissue for the hydrolysis of the monoacylglycerols formed by the action of two kinds of triacylglycerol lipases, lipoprotein lipase and hormone-sensitive lipase.

Adipose Tissue↗
PubMed1981

Effect of cyclic dipeptides containing histidine on pentobarbital narcosis.

We examined the effect of cyclo (His-Pro) and its analogs on pentobarbital narcosis in mice. Cyclo (His-Pro), 500 nmol/mouse, administered via intracerebroventricular (i.c.v.) route significantly prolonged the sleeping time. Methylation of histidine in the structure of cyclo (His-Pro) did not increase the activity of cyclo (His-Pro). Some of other cyclo (His-Pro) analogs, of which proline was replaced with other amino acids, cyclo (His-Phe), cyclo (His-Tyr), cyclo (His-His) and cyclo (D-His-Leu) produced significant prolongation of the sleeping time as compared with cyclo (His-Pro). These results suggest that cyclo (His-Pro) has opposing effect to that of thyrotropin releasing hormone (TRH) and the prolongation of pentobarbital narcosis by cyclic dipeptides might be caused by their central action.

Animals↗
PubMed1981

Effects of intracerebroventricular administration of aliphatic diamines on ingestive behavior in the rat.

We examined the pharmacological effects of intracerebroventricularly administered aliphatic diamines on ingestive behavior in male rats adapted to a 4 hr per day feeding and drinking schedule. 1,2-Ethanediamine (ETD), 1,3-propanediamine (PRD), 1,4-butanediamine (putrescine, PUT), 1,5-pentanediamine (cadaverine, CAD) and 1,6-hexanediamine (HED) suppressed feeding and drinking behavior in a dose-dependent manner, but not unless a relatively high dose (over 80 micrograms) was given. The approximate anorectic potency was HED greater than CAD divided by PUT greater than ETD greater than PRD. A sedation was also produced in fairly good parallel to these alterations in feeding and drinking behavior. Thus, there appears to be a relationship between the length of the carbon chain and the potency of the pharmacological action, and these inhibitory effects on feeding and drinking behavior are probably not due to a specific action on the regulatory system for ingestive behavior, but rather to a nonspecific action.

Animals↗
PubMed1981

Changes in ingestive behavior, serum glucose and free fatty acids concentrations in rats following intracerebroventricular injection of spermine.

We examined the changes in ingestive behavior, serum glucose (Glc) and free fatty acids (FFA) concentrations in male rats following intracerebroventricular (i.c.v.) injection of spermine (SPM). In satiated rats, over a 53.3 nmol of SPM suppressed feeding and drinking behavior in a dose-dependent manner. The median suppressive dose was 90.8 nmol for feeding behavior and 68.3 nmol for drinking behavior. Spermidine also suppressed ingestive behavior but the potency was appreciable weak compared to that of SPM, and the occurrence of the maximal suppression was observed 2-3 days later than that of SPM. The most significant anorexia and adipsia induced by SPM appeared between 16 and 36 hr after i.c.v. administration. SPM (180 nmol) produced a biphasic increase in serum Glc concentration. The 1st peak was at 1 hr and the other peak was 24 hr after the dosing. The same dose of SPM elevated serum FFA concentrations gradually, and the maximal increase appeared 24 hr after the injection. As less than a 120 nmol dose of SPM did not alter serum Glc and FFA concentrations, there seems to be no causal relation between SPM-induced anorexia, and changes in serum Glc and FFA concentrations. Nevertheless, the findings that a very small dose of SPM produced anorexia and adipsia support the possibility that SPM may play some functional role in the brain.

Animals↗
PubMed1981

Abnormalities of iodine and protein in the thyroid of patients with Hashimoto's thyroiditis.

Iodine content, protein content and percentage of thyroglobulin to total protein in the thyroid glands were studied in two groups of 10 patients with Hashimoto's thyroiditis (5 euthyroid and 5 hypothyroid patients) and in 6 normal subject. Iodine content was significantly decreased in both hypothyroid (24 +/- 29 microgram/g wet weight of thyroid tissue, mean +/- S.D., p less than 0.01) and euthyroid (96 +/- 52, p less than 0.01) groups of Hashimoto's thyroiditis compared with those in controls (779 +/- 37). The value of hypothyroid group was significantly smaller than that of euthyroid group (p less than 0.05). A significant negative correlation was obtained between thyroidal iodine content and serum TSH (r = -0.68, y = -0.41 chi + 55.6, p less than 0.05). Thyroidal protein and percentage of thyroglobulin to total thyroidal protein were also decreased in Hashimoto's thyroiditis compared with controls, while there was no difference between euthyroid and hypothyroid groups in these values. The percentage of thyroglobulin-bound 131I obtained by in vitro iodination of thyroglobulin in Hashimoto's thyroiditis appeared to be decreased in 2 cases of hypothyroid group. Some immunological reaction occurring in Hashimoto's thyroiditis may change the structure of thyroglobulin and in turn the normal iodination of thyroglobulin may be disturbed.

Adult↗
PubMed1981

[Effects of intraperitoneally administered spermine on ingestive behavior, serum glucose and free fatty acids concentrations in rats (author's transl)].

The intraperitoneal administration of spermine (SPM) produced a dual-phasic feeding suppression. The first suppression appeared immediately after the administration and disappeared on the 2nd day. The next suppression was observed on the 3rd day and continued for 2-4 days. The 50% dose which induced suppression on the 3rd day was 64.9 (60.9-69.2) mumol/kg. Drinking behavior was also suppressed on the 1st day, but was facilitated on the 2nd day and lasted for 4-5 days. Serum glucose and free fatty acids concentrations increased after the administration of SPM (80 mumol/kg). Their maximal values obtained at 3 hours after the dosing were 116% and 156% of the control values, respectively. These increases in both substances were not observed in the adrenal-demedullated rats. The same dose of SPM enhanced serum glutamic oxaloacetic transaminase and glutamic pyruvic transaminase activities. The maximal values obtained at 2 hours after the dosing were 264% and 142% of the control values, respectively. On the contrary, serum cholinesterase activity decreased to 44% of the control value at the same hour. These variations of the enzyme activities disappeared at 3 hour, but were again observed between the 1st and 4th days. The results suggest that SPM releases catecholamines from the adrenal medulla, and exerts a toxic action on the liver. The anorexia induced by SPM may be due to these actions on the viscera.

Alanine Transaminase↗