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Biomedical subjects

T Ishida

Publications and source records attributed to T Ishida.

At least 1,135 records · Page 63Linked to original sources
PubMed1984

[Clinicopathological study of breast cancers associated with other primary cancers].

Thirty six cases of breast cancer associated with other primary cancer were found out among 1160 patients with primary breast cancer. They consisted of 6 synchronous combination and 30 metachronous, in which 23 were detected as the first lesion and 7 were the second. The other organs involved by cancer were the stomach (11), thyroid (9), colon or rectum (5), uterus (3), and others (8). Although the TNM stage of the breast cancer was mostly in stage I or II (91.6%), the prognosis was poor in the metachronous cases, depending on the nature of the second primary cancer. It is important to detect and treat a second primary cancer in the early stage.

Adult↗
PubMed1983

Stacking interaction of indole ring with thiazolium ring and effect for H-D exchange reaction of thiamin.

As part of a program to clarify the possible binding mode of tryptophan with thiamin coenzyme, the interaction between the indole and thiazolium rings has been studied by using a model compound, 2-(3,4-dimethylthiazolium-5-)ethyl indole-3-propionate, and the prominent stacking formation between both rings has been evidenced by the spectroscopic and X-ray crystallographic methods. The faster H-D exchange reaction of thiamin C2 proton observed in the presence of indole than in the lack would be resulted from the pi-pi charge-transfer interaction between the indole ring and the thiazolium ring of thiamin.

Chemical Phenomena↗
PubMed1983

The stacking interactions in 7-methylguanine-tryptophan systems, a model study for the interaction between the 'cap' structure of mRNA and its binding protein.

Stacking interactions were shown by spectroscopic and X-ray crystallographic studies to be formed between the tryptophan and the protonated 7-methylguanine derivatives. These interactions would be in part responsible for the specific interaction between the 5'-terminal capped structure of mRNA and its binding protein.

Carrier Proteins↗
PubMed1983

Inter- and intramolecular stacking interaction between indole and adeninium rings.

Crystals of 1,9-dimethyladeninium-indole-3-acetate (1:1) complex (I) and 9-(3-indol-3-ylpropyl)-1-methyladeninium iodide (II), an inter- or intramolecular model for the stacking interaction between the tryptophanyl residue and the methylated (or protonated) adenine base, were subjected to X-ray analyses. Nearly parallel stacking and interplanar spacing near to 3.4 A were observed between the indole and adeninium rings of both crystals. In particular, one of the two stacking pairs formed in I showed the existence of a partial charge-transfer interaction in their ground states. On the basis of the molecular orbital consideration, the mutual orientation between these stacked aromatic rings is considerably governed by the orbital interaction between the highest occupied molecular orbital of the indole ring and the lowest unoccupied one of the adeninium ring. The ring stacking observed in II was stabilized by the strong coupled dipole-dipole interaction. Absorption, fluorescence, and proton nuclear magnetic resonance spectra indicated the existence of a stacking interaction in the aqueous solutions of I and II, as well as in their crystalline states. The biological implication for the observed stacking interactions has been discussed.

Adenine↗
PubMed1983

X-ray structural studies and physicochemical properties of cimetidine polymorphism.

Four crystalline forms of cimetidine, three anhydrous (forms A, B, and D) and a monohydrate (form C), obtained by slow evaporation of aqueous solutions of varying concentrations were characterized by IR spectroscopy, X-ray powder patterns, dissolution rates in deionized water, and thermal analyses. Among the three anhydrous forms of cimetidine, form A was thermodynamically more stable than the others. The structural conversion of form C into form A on dehydration was confirmed by IR spectroscopy and X-ray powder patterns. The structures of forms C and D were determined using X-ray diffraction. Form D was of spirally curled conformation; it was linked in a head-to-tail arrangement with the neighboring molecules via intermolecular hydrogen bonds between the imidazole nitrogen and guanidine nitrogen atoms. Form C was characterized by its folded conformation due to the weak stacking interaction between the imidazole and guanidine moieties; there was stabilization by double hydrogen bond formation with neighboring molecules and via water molecules of crystallization. The dissolution rate constant in deionized water for form C was approximately 1.29, 1.70, and 1.90 times greater than those measured for forms A, D, and B, respectively. There was a similar relationship among the four forms with respect to the rates of inhibition of stress ulceration. Regarding the molecular conformations of the crystalline forms and the rates of inhibition of stress ulceration, the gauche orientation of the guanidine group relative to the imidazole ring would be the conformation necessary for effective binding to the histamine H2-receptor. The compactly folded conformation of form C appears to be optimal for binding to the active site of the receptor and for clinical efficacy.

Animals↗
PubMed1983

On the interaction between flavin-adenine rings and between flavin-indole rings by X-ray structural studies.

Two crystal structures of 7,8-dimethylisoalloxazine-10-acetic acid:adenine-9-ylethylamine(1:1)hepatahydrate and 7,8-dimethylisoalloxazine-10-acetic acid:L-tryptophan methylester(1:1)heptahydrate complexes were determined as models for the flavin-adenine and flavin-indole interactions, respectively. In the former complex, both molecules were connected by Hoogsteen-type hydrogen bonds between the pyrimidinoid portion of flavin and the adenine, in addition to the normal stacking of both aromatic rings. On the other hand, parallel stackings and intermolecular vertical spacings less than the normal van der Waals separation distance were observed between the flavin and indole rings of the latter complex, indicative of the pi D-pi A charge-transfer interaction in their ground states. Comparing with the X-ray findings of related complexes, we discussed the interaction modes between flavin and adenine rings and between flavin and indole rings.

Adenine↗
PubMed1983

The effect of ingestion of meat on hepatic extraction of insulin and glucagon and hepatic glucose output in conscious dogs.

The effect of ingestion of protein on hepatic extraction of insulin and glucagon and hepatic glucose output were investigated in conscious dogs. The ingestion of meat stimulated both insulin and glucagon secretion but the glucagon response was much more rapid and greater than that of insulin. Secretion of glucagon demonstrated a biphasic pattern while insulin release was monophasic. The fractional hepatic extraction of glucagon increased gradually from the basal value of 15 +/- 3% to a peak of 36 +/- 5% at 90 min, and that of insulin increased from the basal level of 41 +/- 2% to 54 +/- 4% at 45 and 60 min. The increased hepatic extraction of glucagon and insulin after meat ingestion may be explained by neural or hormonal signals from the gut. The blood glucose and hepatic glucose output did not increase significantly despite the significant decrease of the portal vein insulin to glucagon molar ratio as well as the significant decrease of the molar ratio of the hepatic uptake of these hormones. The absence of greater hepatic glucose production despite the augmented glucagon secretion and decreased portal vein insulin to glucagon molar ratio could reflect down regulation by glucagon.

Animals↗
PubMed1983

A new inductive applicator for hyperthermia.

We have designed a new type of applicator for inductive heating which consists of a one-turn, square, column-like coil, through which RF current flows. The material to be heated is placed alongside one of the external sides of the coil. The depth of penetration from an applicator with a height of 20 cm, width of 20 cm, depth of 60 cm was calculated to be 11.7 cm. However, in experiments using a muscle-equivalent agar phantom 60 cm X 60 cm X 60 cm, the penetration depth proved to be 9.6 cm; but in another experiment using a smaller phantom 20 cm X 40 cm X 60 cm, the penetration depth was 6.3 cm. This means that the depth of penetration depends not only on the size of the applicator but also on the shape of the material heated. Our study clearly showed that this applicator produces much less heat in the fat layer than in the muscle layer and should be an inductive applicator suitable for deep heating cancer therapy.

Diathermy↗
PubMed1983

Growth of Tyzzer's organism in primary monolayer cultures of adult mouse hepatocytes.

The Tyzzer's disease organism was grown in primary monolayer cultures of adult mouse hepatocytes prepared by collagenase perfusion. The organisms produced a plaque-like cytopathic effect involving almost the whole culture around 72 h post-infection when the bacterial growth reached a maximum. The organisms showed specific immunofluorescence, and electron microscopy revealed that intracellular organisms had peritrichous flagella and underwent cell division. After intravenous inoculation of the infected cell culture into mice, necrotic hepatitis was produced and the organisms, recovered from the liver lesion, could be propagated in primary culture of mouse hepatocytes.

Animals↗
PubMed1983

Absence of hepatic extraction of pancreatic polypeptide in conscious dogs.

In 15 conscious dogs basal portal vein pancreatic polypeptide (PP) (306 +/- 8 pg/ml) exceeded both hepatic vein PP (255 +/- 8 pg/ml) and arterial PP (244 +/- 9 pg/ml) and increased rapidly 10 min after oral glucose administration. In contrast to oral glucose, intraportal glucose infusion decreased PP levels from 45 min until the end of the infusion. Meat ingestion rapidly and promptly increased PP. During the basal state, hepatic extraction of total immunoreactive PP was 10 +/- 4%, not significantly different from zero, of the 150 +/- 14 ng/min presented to the liver. Fractional hepatic extraction of PP did not change after oral glucose, meat ingestion, or intraportal glucose infusion. Chromatographic analysis showed at least four different components of immunoreactive PP. The first peak eluted with the void volume, the second peak between the void volume and authentic PP, and the third peak coincided with authentic PP. When present, the fourth peak eluted after authentic PP. More than half of the immunoreactive PP in the basal state eluted with authentic PP, whereas about one-third was found in the second peak. The marked alterations in PP after meat, oral glucose, or intraportal glucose and atropine reflected primarily changes in the third peak. The fractional hepatic extraction of all the components was very similar.

Animals↗
PubMed1983

Differential effects of oral, peripheral intravenous, and intraportal glucose on hepatic glucose uptake and insulin and glucagon extraction in conscious dogs.

The effect of equal (1.1 +/- 0.1 g/kg body wt) amounts of glucose administered orally, or by peripheral intravenous or intraportal infusion on hepatic glucose uptake and fractional hepatic extraction of insulin and glucagon was studied in conscious dogs with chronically implanted Doppler flow probes on the portal vein and hepatic artery and catheters in the portal vein, hepatic vein, carotid artery, and superior mesenteric vein. Portal vein and hepatic vein plasma flow increased only after oral glucose administration. Arterial plasma glucose increased equally to 150-160 mg/100 ml after all three routes of glucose administration. Portal vein glucose was similar after oral (195 +/- 15 mg/100 ml) and intraportal glucose infusion (215 +/- 11 mg/100 ml) and significantly higher than after peripheral intravenous glucose. Hepatic glucose uptake after oral (68 +/- 4%) and intraportal glucose administration (65 +/- 7%) significantly exceeded that after peripheral intravenous glucose infusion (23 +/- 5%). The amount of insulin above basal presented to the liver during the 180 min after oral glucose was 7.6 +/- 1.3 U, 4.3 +/- 0.6 U after intraportal glucose, and 4.1 +/- 0.6 U after peripheral intravenous glucose. Hepatic extraction of insulin increased significantly after oral glucose (42 +/- 3 to 61 +/- 4%), but was unchanged after intraportal and peripheral intravenous glucose administration. When the portal vein glucose levels achieved during peripheral intravenous glucose infusion for 90 min were maintained by a subsequent 90-min intraportal glucose infusion, hepatic glucose uptake was significantly greater during the intraportal glucose infusion. Glucagon secretion was suppressed equally after oral glucose, intraportal glucose, and peripheral intravenous glucose administration; fractional hepatic extraction of that hormone, which was significantly less than that of insulin, was unchanged. These results indicate that hepatic glucose uptake is significantly greater after oral and intraportal glucose administration than after peripheral intravenous glucose infusion. This difference is not simply related to the amount of glucose or insulin presented to the liver and the increased hepatic glucose uptake did not depend solely upon the augmented fractional hepatic extraction of insulin. Hepatic extraction of insulin and hepatic glucose uptake appear to be regulated independently.

Administration, Oral↗