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Biomedical subjects

I Arai

Publications and source records attributed to I Arai.

At least 19 recordsLinked to original sources
PubMed1992

Effect of stilbene derivatives on gastric H+, K(+)-ATPase.

The effect of naturally occurring hydroxystilbene, 3,3',4,5-tetrahydroxystilbene (piceatanol), and its derivatives on gastric H+, K(+)-ATPase was studied. Piceatanol inhibited H+, K(+)-ATPase in a dose-dependent manner. The 50% inhibition value was 4.3 x 10(-6) M. It was found from the kinetic study that the inhibition of the enzyme by piceatanol was competitive with respect to ATP and was noncompetitive with respect to K+. Piceatanol also effectively inhibited gastric acid secretion. However, methylation of phenolic hydroxy groups of piceatanol resulted in a complete loss of inhibition of the enzyme and acid secretion, suggesting the role of phenolic hydroxy groups in the inhibition. The study on hydroxystilbene derivatives also showed that phenolic hydroxy groups are important in the interaction with H+, K(+)-ATPase and that stilbenes with neighbouring hydroxy groups are the most effective inhibitors.

Adenosine Triphosphate↗
PubMed1992

Inhibition of gastric H+,K(+)-ATPase and acid secretion by cassigarol A, a polyphenol from Cassia garrettiana Craib.

The effects of cassigarol A, a naturally occurring polyphenol, on gastric H+,K(+)-ATPase and gastric acid secretion were studied. Cassigarol A inhibited H+,K(+)-ATPase and K-stimulated p-nitrophenyl phosphatase from hog gastric mucosa with 50% inhibition of 1.2 x 10(-6) and 6.3 x 10(-6) M, respectively. The kinetic study showed that the inhibition of H+,K(+)-ATPase by cassigarol A was competitive with respect to ATP and non-competitive with respect to K+. Cassigarol A inhibited both H+,K(+)-ATPase-mediated proton transport and 2-deoxy-D-glucose-induced acid secretion. On the other hand, cassigarol A acetate, in which phenolic hydroxy groups are acetylated, was not effective in the inhibition of enzyme activity and acid secretion. These results indicate that cassigarol A is a potent inhibitor of gastric H+,K(+)-ATPase, that the anti-secretory activity of cassigarol A is related to the inhibition of H+,K(+)-ATPase and that an important moiety of cassigarol A in the interaction with the enzyme is the phenolic hydroxy groups.

Adenosine Triphosphatases↗
PubMed1992

Simultaneous determination of cortisol and cortisone in human plasma by stable-isotope dilution mass spectrometry.

A method for the simultaneous determination of cortisol and cortisone in human plasma was developed using capillary gas chromatography-mass spectrometry-selected ion monitoring. [2H5]Cortisol and [2H5]cortisone were used as internal standards. Cortisol and cortisone in plasma were determined from the peak-height ratios of the [M-31] fragment ions of the methoxime-trimethylsilyl derivatives of cortisol and [2H5]cortisol (m/z 605 and 610) and of cortisone and [2H5]cortisone (m/z 531 and 536). Sensitivity, specificity, precision, accuracy and reproducibility of the method were demonstrated to be satisfactory for measuring the circulating concentrations of cortisol and cortisone.

Cortisone↗
PubMed1991

Putative role of endogenous insulin in cysteamine-induced hypersecretion of gastric acid in rats.

The effects of cysteamine on gastric acid secretion and blood glucose levels were examined in rats. Cysteamine given subcutaneously in doses of 100-300 mg/kg, decreased the level of arterial blood glucose dose dependently, but had no effects on the level of the jugular venous blood glucose. Glucose uptake into the brain, as obtained by subtracting level of the jugular venous blood glucose from level of the arterial blood glucose, was significantly decreased by the administration of cysteamine. The uptake of [14C]2-deoxy-D-glucose into the brain was also decreased by the administration of cysteamine. Cysteamine dose dependently increased gastric acid secretion and induced ulcers in the gastroduodenum. The increased in acid secretion and the decrease of the value of glucose uptake into the brain had related time courses. Cysteamine significantly increased the level of serum insulin and induced hypoglycemia. These effects of cysteamine were completely blocked by pretreatment with streptozotocin. The hypersecretion of gastric acid and gastroduodenal ulcerations were also significantly inhibited by streptozotocin pretreatment. Infusion of glucose also inhibited the cysteamine-induced gastric acid secretion. These results suggest that cysteamine enhances the gastric acid secretion induced by the hypoglycemia and by the decrease in glucose uptake by the brain.

Animals↗
PubMed1991

Treatment of pars planitis with cryotherapy.

Cryotherapy was performed on 28 eyes exhibiting massive exudates (snowbank) over the pars plana and the ora serrata. Twenty-six patients ranging in age from 8 to 52 years were treated and then followed up for a median of 34 months. Eleven eyes needed repeat cryotherapy. After cryotherapy, retinal vasculitis and vitreous opacities decreased in most eyes. Although only 3 of 5 eyes with a snowbank greater than 90 degrees and treated over 1 year from the onset achieved visual acuity of 20/25 or better, all 12 eyes with a snowbank smaller than 60 degrees and treated within 3 months after the onset maintained a visual acuity of 20/25 or better. The prognosis was not different from the 20 eyes that received systemic steroid treatment and the 8 eyes that received no systemic steroids. We recommend cryotherapy as the primary treatment for pars planitis with a snowbank.

Adolescent↗
PubMed1990

Characterization of sulpiride-displaceable 3H-YM-09151-2 binding sites in rat frontal cortex and the effects of subchronic treatment with haloperidol on cortical D-2 dopamine receptors.

We investigated the pharmacological properties of the sulpiride-displaceable binding sites labeled by 3H-YM-09151-2 in rat frontal cortex, compared to those in striatum. The IC50 value of ketanserin was 486 nM, which was apparently different from its affinity for the 5HT-2 receptor. Various dopamine antagonists showed almost the same inhibitory effects for binding site in frontal cortex and striatum. Sulpiride-displaceable 3H-YM-09151-2 binding sites were considered to be D-2 dopamine receptors. After subchronic treatment with haloperidol, the D-2 receptor density of frontal cortex (0.55 fmol/mg tissue) increased to the same extent (about 25%) as striatum without significant change in apparent affinity.

Animals↗
PubMed1990

Alteration of metabolism of acetylcholine induced by 2-deoxy-D-glucose in the gastroduodenum of the rat.

2-Deoxy-D-glucose (2-DG) administered intraperitoneally, dose-dependently increased the secretion of gastric acid, and the changes were comparable with those on the activity of choline acetyltransferase (CAT) and acetylcholinesterase (AChE) in the stomach. Double-reciprocal plot analysis of the increased activity of CAT and AChE, induced by 2-DG, showed that the changes were due to the increase of Vmax, with no change in the Km-value for the substrates. The uptake of [3H]choline and subsequent synthesis of [3H]ACh was observed in the forestomach, corpus and antrum of the stomach and in the duodenum. 2-Deoxy-D-glucose significantly increased the uptake of [3H]choline and synthesis of [3H]ACh in every region of the stomach and in the duodenum, in a dose-dependent manner. The increase of secretion of gastric acid, induced by 2-DG paralleled that of uptake of [3H]choline and synthesis of [3H]ACh at an early stage. The conversion of [3H]choline taken up to [3H]ACh was negligibly influenced by 2-DG. Neither the content of ACh and choline, nor the turnover rate of ACh, were changed by administration of 2-DG. 2-Buten-4-olide (2-B4O), which inhibits the activity of the vagus nerve through the central nervous system, prevented 2-DG-induced uptake of [3H]choline and subsequent synthesis of [3H]ACh, as well as the increase in secretion of gastric acid. These results suggest that the uptake of [3H]choline and subsequent synthesis of [3H]ACh are closely related to the neuronal activity of the vagus nerve, and that cholinergic neuronal activity is dependent upon quantitative changes of metabolism of ACh in the gastroduodenum.

Acetylcholine↗
PubMed1990

Effect of an endogenous satiety substance, 2-buten-4-olide, on gastric acid secretion and experimental ulceration in rats.

The involvement of a feeding-related endogenous sugar acid, 2-buten-4-olide (2-B4O) on central regulation of gastric acid secretion, and its antiulcer effects on several gastric and duodenal experimental ulcer models were investigated in rats. Spontaneous gastric acid secretion was not affected by 2-B4O at doses below 10 mg/kg. The peripheral secretagogue-stimulated gastric secretions were significantly increased by pretreatment with 2-B4O. Gastric acid secretion induced by 2-deoxy-D-glucose (2-DG) was significantly suppressed by pretreatment with 2-B4O at doses between 0.1 and 100 mg/kg. Gastric and duodenal ulcerations induced by cold stress plus indomethacin, restraint and water immersion stress, pylorus ligation or cysteamine were also inhibited by pretreatment with 2-B4O. The results suggest that antiulcer effects of 2-B4O are due to suppression of gastric acid secretion via reduction of activity of the vagus nerve and gastric-related hypothalamic neurons. Thus, 2-B4O may be useful for treatment of gastroduodenal ulcer.

4-Butyrolactone↗
PubMed1990

Bromination, no-carrier-added radiobromination and simultaneously-occurring chlorination by chloramine T.

Factors regulating initial rates of bromination, no-carrier-added radiobromination and simultaneously-occurring chlorination by chloramine T were studied using a neuroleptic drug spiperone as the substrate. Besides the factors such as initial concentrations of chloramine T, substrate and bromide ions, upon which the rates were dependent in first, second or zero-order, the water-acetic acid composition or the hydrogen ion concentration of the solutions, where the reactions took place, was found to play a key role. By controlling these factors, optimal radiobromination conditions, where radiobromination proceeds effectively whilst simultaneously-occurring chlorination is kept from proceeding at a high rate, thus resulting in radiobrominated radiopharmaceuticals of high specific activity (10 Ci/mumol) and high radiochemical and chemical purity, could be fulfilled.

Bromine↗
PubMed1990

Effects of the new H2-receptor antagonist 3-amino-4-[4- [4- (1-piperidinomethyl)-2-pyridyloxy]-cis-2-butenylamino]-3-cyclobutene-1, 2- dione hydrochloride on gastric acid secretion and ulceration.

The effect of 3-amino-4-[4-[4-(1-piperidinomethyl)-2-pyridyloxy]-cis- 2-butenylamino]-3-cyclobutene-1,2-dione hydrochloride (IT-066), a new H2-receptor antagonist, on gastric acid secretion and on various experimental ulcers was investigated. IT-066 showed very potent and long lasting antisecretory action in pylorus ligated rats. The inhibitory potency of IT-066 given subcutaneously for gastric acid secretion was 1285 and 44 times higher than for cimetidine and famotidine, respectively. The duration of the inhibitory action of IT-066 was significantly longer than that of famotidine and cimetidine. In pylorus ligated rats, IT-066 showed almost 20 times higher potency than omeprazole with intraduodenal administration, and almost the same duration of action as omeprazole with one tenth the dose in oral administration. IT-066 showed a powerful protective effect on various experimental ulcer models. The potency of IT-066 administered subcutaneously was significantly higher compared with that of cimetidine, famotidine and omeprazole. IT-066 given orally also showed a more powerful antiulcer effect than cimetidine and omeprazole, and was comparable with that of famotidine in restraint and water immersion stress and cold-stress plus indometacin induced ulcer models in rats. These results suggest that IT-066 has powerful and long lasting antisecretory and antiulcer effects and is a useful antisecretory drug for treatment of peptic ulcer diseases.

Animals↗
PubMed1990

[Noncontact and noninvasive microwave biological measurements].

Without contact probes, the signals of small human body surface movements were obtained with microwave Doppler sensors using a two-phase interferometric method. The signals were then compared with mechanocardiographic records routinely obtained by contact transducers. Furthermore, this system was applied to patients wearing clothes. The study subjects consisted of 20 cardiac patients and 10 normal controls. 1. The microwave signals obtained in the cervical and precordial regions were similar to those of the mechanocardiographic recordings, such as the carotid pulse and jugular venous pulse tracings and the apexcardiogram. There was a significant correlation between left ventricular ejection time (LVET) obtained by microwave Doppler sensors and that by the carotid pulse tracing (r = 0.95). 2. The signals of the microwave Doppler sensor were obtained from the patients wearing clothes. The heart beat components were distinguished from respiratory motion and patients' movements using band-pass filters. These results suggest that this method is capable of evaluating cardiac function noninvasively and thus has a distinct advantage in the field of non-contact measurements.

Heart Function Tests↗
PubMed1988

Sensitization of amino acid derivatives obtained from Edman degradation with radioactively-labeled iodohistamine.

The minimum amount of proteins and peptides required for sequencing is constantly decreasing as more sensitive microsequencing methods are developed. The sensitization of and Edman degradation product is one such method. We took the 2-anilino 5-thiazolinone amino acid intermediates obtained from Edman degradation by conventional sequencing procedures, and quantitatively reacted them with a primary amine. The amine used was radioactive [125I]iodohistamine, which affords highly sensitive detection. The labeled amino acid derivatives were separated by thin layer chromatography. Ten femtomoles of a labeled derivative can be detected by autoradiography.

Amino Acids↗
PubMed1988

[Effect of gomisin A (TJN-101), a lignan compound isolated from Schisandra fruits, on liver function in rats].

TJN-101 [+)-(6S, 7S, R-biar)-5,6,7,8-tetrahydro-1,2,3,12-tetramethoxy- 6,7-dimethyl-10,11-methylenedioxy-6-dibenzo [a, c] cyclooctenol) is one of the lignan compounds isolated from Schisandra fruits. When TJN-101 was administered orally at the doses of 3-100 mg/kg/day for 4 days, bile secretion, hepatic excretion of dye or hepatic hemodynamics 24 hr after the last dose was investigated in comparison with the phenobarbital (100 mg/kg/day)-treated group. Bile flow was dose-dependently increased; in contrast, biliary concentration of bile acids was decreased in TJN-101 (30 and 100 mg/kg/day)-treated groups. Similar changes were also observed in the phenobarbital-treated group. These results suggested that the enhancement of bile secretion caused by TJN-101 or phenobarbital was due to an increase of a bile acid-independent fraction. In the bromosulfophthalein (BSP) clearance test for liver function, both TJN-101 (30 and 100 mg/kg/day) and phenobarbital accelerated the disappearance from the blood and biliary excretion of BSP. Hepatic hemodynamics was examined by the hydrogen clearance method and measurement of liver wet and dry weight. Liver blood flow tended to increase in the TJN-101 (10-100 mg/kg/day) or phenobarbital-treated group. On the other hand, TJN-101 (3-100 mg/kg/day) or phenobarbital hardly altered the water content of the liver. These results suggested that the liver enlargement caused by both compounds was not accompanied with hepatic edema and that the enhancement of bile secretion or hepatic excretion of BSP might be related to an increase of liver blood flow.

Animals↗
PubMed1987

Effects of restraint and water-immersion stress and insulin on gastric acid secretion in rats.

Effects of restraint and water-immersion stress (RWIS) and of insulin injection on gastric acid secretion were investigated in relation to blood glucose levels and to brain glucose uptake in rats. Venous blood glucose levels (VBG) were significantly increased while arterial blood glucose level (ABG) was slightly increased by RWIS. In contrast, ABG and VBG were significantly decreased by administration of insulin; the decrease in ABG was greater than that in VBG. Glucose uptake into the brain, calculated from the ABG-VBG, was significantly decreased both by RWIS loading and by insulin administration. The uptake of [14C] 2-deoxy-D-glucose [( 14C]-2DG) into the brain was also significantly decreased in RWIS-loaded or insulin-treated rats. Gastric acid output was significantly increased both by RWIS loading and by insulin administration. The increased acid output paralleled the decrease of glucose uptake into the brain in RWIS-loaded and insulin-treated rats. Results suggest that RWIS-induced gastric acid secretion is regulated by brain glucose uptake and that this gastric acid secretion is a hypothalamic neuron-mediated event as is insulin-stimulated gastric acid secretion.

Animals↗