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Biomedical subjects

M Ishida

Publications and source records attributed to M Ishida.

At least 361 records · Page 20Linked to original sources

High frequency of spontaneous acute myocardial infarction due to small coronary artery disease in dead (NZWxBXSB)F1 male mice.

To determine whether or not male (NZWXBXSB)F1 [WXB)F1) mice exhibiting a lupus-like syndrome died of acute myocardial infarction (MI), and whether acute MI is directly related to small coronary artery disease, acute and old MIs were examined histologically in 55 dead (WXB)F1 male mice and 30 age-matched, surviving (WXB)F1 male mice used as a control group. In each heart from the 15 dead mice with MI and the five surviving mice without MI, 300 to 400 5-microns-thick serial sections were made; every fourth section was stained. Acute MI was found in 35 (64%) dead mice and in one (3%) survivors, whereas old MI was found in 50 (91%) dead mice and 17 (57%) survivors: a significant difference between the dead and surviving mice. The MIs were numerous, scattered, and small in most mice. Quantitative analysis revealed that the percentage of acute MI and old MI in the left ventricular (LV) wall was 6% +/- 11% and 3% +/- 3% in the dead group, and 0.4% and 2% +/- 3% in the control group. This indicated that recurrent acute MI is a major factor in the death of the mice. Although all the epicardial major coronary arteries of the (WXB)F1 male mice were intact, significant stenoses were noted in the intramyocardial small arteries. The serial sections in the 15 dead mice with MI revealed 1) segmental occlusive thrombi in the infarct-related small coronary artery in 14 of the 20 foci of acute anemic MIs, two of the 18 foci of acute hemorrhagic MIs, and four of the 58 foci of old MIs; and 2) segmental intimal thickenings in the infarct-related small artery in six of the 20 foci of acute anemic MIs, two of the 18 foci of acute hemorrhagic MIs, and 56 of the 58 foci of old MIs. There was no evidence of small coronary artery disease in the surviving mice without MI. The thrombus would result in thickened intima as MI progresses from the acute to the old stage. Because it was established that acute MI of hemorrhagic type follows reperfusion after transient occlusion of the coronary artery, hemorrhagic acute MI with rare incidence of thrombi in this mouse suggests that thrombolysis occurs after occlusion due to thrombus formation. Thus, the pathogenesis of multiple MIs is occlusive thrombi, recanalization in small coronary arteries or both. Some of the mice had dilated cardiomyopathy (DCM)-like features (marked LV dilatation).(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

Interconvertible hairpin structure found in the replication origin of phage G4 single-stranded DNA.

We found a synthetic GCGAAAGC fragment with a mobility greater than that of other oligodeoxyribonucleotides in gel electrophoresis to take on a stable hairpin structure possessing two terminal G-C base pairs. The GCGAAAGC sequence is also found in the replication origin of phage G4 single-stranded DNA, but the hairpin structure originally proposed differs from that of the GCGAAAGC fragment we have studied. Possibility of rearrangement of the secondary structure in the replication origin of phage G4 was examined in relation to its replication initiation mechanism.

Bacteriophages↗

[Chemical pleurodesis induced with fibrin glue in the treatment of inoperable spontaneous pneumothorax].

Chemical pleurodesis induced with fibrin glue (fibrinogen 1.0 g, thrombin 500 mu, 2% CaCl2 10 ml, tranexamic acid 10 ml) was performed in 6 cases with spontaneous pneumothorax in whom surgery was not indicated because of various reasons, such as low pulmonary function or old age. These cases were complicated with left pneumonectomy, bilateral emphysema, pulmonary tuberculosis and interstitial pneumonia. In all cases, favorable results were obtained and there was no recurrence. As side effects, only transient low grade fever and slight chest pain were observed with no liver damage or pleural thickening. These results suggest that chemical pleurodesis induced with fibrin glue is very useful in the treatment of inoperable spontaneous pneumothorax.

Aged↗

[Study of serum level of antithrombin-III antigen, antithrombin activity, and its ratio of AT-III-heparin complex formation in maintenance hemodialysis patients].

The plasma level of Antithrombin-III (AT-III) antigen, antithrombin activity and the ratio of AT-III-heparin complex formation have been studied in 20 patients with chronic glomerulonephritis on regular hemodialysis at two occasions with 2 year interval (in 1986 and 1988), and studied as to each variation in each plasma levels, and compared with the period of length of hemodialysis-history of individual cases. A significant decrease was found not only in plasma level of AT-III antigen (25.7 +/- 4.1 mg/dl to 23.4 +/- 3.9 mg/dl), but also in antithrombin activity (90.8 +/- 11.8% to 85.2 +/- 16.8%). Moreover and ratio of AT-III-heparin complex formation was significantly reduced during two years, too (50.7 +/- 3.0% to 53.0 +/- 1.5%). Similarly, a significant negative correlation could be found on the comparison between the duration of hemodialysis and each plasma levels of AT-III antigen (r = -0.27), antithrombin activity (r = -0.33), and as well as ratio of AT-III-heparin complex formation (r = -0.34). Therefore, it was interestingly suggested the possibility that prolonged hemodialysis treatment induced a functional loss of AT-III, especially in a capacity to form a AT-III-heparin complex due to partial loss of the affinity for heparin.

Adult↗

[Correlations between results of selective intracoronary thrombolysis and histologic findings of the infarct-related coronary arteries].

To define the histopathogenesis of successful and unsuccessful recanalization following selective intracoronary thrombolysis, coronary angiography (CAG) in thrombolysis and histologic findings were compared in 13 patients who died within four days (mean 1.5 days) after the procedure. Thirteen infarct-related arteries were evaluated in respect to recanalization; presence of an intraluminal thrombus, and rupture and hemorrhage of atheromatous plaques were histologically evaluated in serial sections. Intraluminal thrombi of the infarct-related coronary artery were found in all of the five cases with unsuccessful recanalization and in none of the eight cases with successful recanalization. Rupture and hemorrhage of atheromatous plaques in infarct-related arteries were observed in all of the five cases with unsuccessful recanalization and in seven of the eight cases with successful recanalization. It was concluded that 1) in recanalized cases, thrombi are considered to be lysed; 2) unsuccessful recanalization does not necessarily indicate the absence of thrombi; and 3) rupture and hemorrhage of atheromatous plaques do not affect recanalization.

Aged↗

Expression of interleukin-2 receptor (IL-2R) in feline peripheral blood lymphocytes.

A monoclonal anti-interleukin-2 receptor (IL-2R) antibody has been identified as a putative antibody against the human IL-2R. In the present study, anti-Tac antibody CD-25 was used to determine cell expressing IL-2 receptor in feline peripheral blood lymphocytes by means of direct immunofluorescence tests and complement-mediated lymphocytotoxicity tests. With complement-mediated lymphocytotoxicity, approximately 18% of feline peripheral blood lymphocytes expressed the receptors. By the direct immunofluorescence test, we found approximately 22% of IL-2R positive cells in lymphocytes of feline peripheral-blood.

Animals↗

[A case of gastric carcinoid tumor with coexisting adenocarcinoma in the same tumor].

A case of a gastric carcinoid tumor with a coexisting adenocarcinoma in the same tumor is reported. The patient was a 71-year-old man who complained of epigastralgia. His physical examination and routine laboratory data were unremarkable. An upper GI x-ray series and the gastroendoscopic findings, however, demonstrated a Borrmann 2-like tumor of the antrum. An endoscopic biopsy specimen from the tumor revealed that it was a gastric adenocarcinoma. Therefore, a subtotal gastrectomy with a lymph node dissection was performed. The resected specimen showed a Borrmann 2-like tumor, but also that infiltration was limited to within the submucosal layer. The pathological findings revealed that the tumor contained two differential component structures (a carcinoid and an adenocarcinoma). The carcinoid and adenocarcinoma structures coexisted with transitional changes that connected both structures. Pathohistologically, it was thought that these two differential components developed from a common origin.

Adenocarcinoma↗

Effects of pancreatic polypeptide on basal and meal stimulated secretion of gastrointestinal, pancreatic and adrenocortical hormones in the dog.

We have assessed the effects of intravenous infusion of bovine pancreatic polypeptide (PP) (1 microgram kg-1 h-1) on the basal and postprandial secretion of gastrointestinal, pancreatic and adrenocortical hormones in normal dogs. Bovine PP within the physiological range increased plasma cortisol levels transiently but significantly. PP elicited an inhibition of insulin response to a protein-rich meal, and tended to reduce the gastrin response. There were, however, no significant changes in basal or postprandial plasma concentrations of motilin and pancreatic glucagon during PP infusion. These results suggest that PP may have a role in controlling insulin secretion from the pancreas. The possible mechanisms are discussed mainly on the basis of vagal innervation.

Adrenal Cortex Hormones↗

Acromelic acid is a much more potent excitant than kainic acid or domoic acid in the isolated rat spinal cord.

Excitatory actions of acromelic acid were investigated in the isolated newborn rat spinal cord. Test compounds were added to the perfusing fluid and the responses were recorded from the ventral root extracellularly. Acromelic acid caused a depolarizing response in a dose-dependent manner and the depolarizing activity of acromelic acid was superior to that of other kainoids such as kainate and domoate. The depolarization induced by acromelate was not affected by NMDA antagonists at all. Acromelic acid was proved to be one of the most potent agonists of excitatory amino acids in both vertebrates and invertebrates.

Animals↗

Excitatory action of a plant extract, stizolobic acid, in the isolated spinal cord of the rat.

Actions of stizolobic acid, stizolobinic acid and their derivatives were examined on the isolated spinal cord of the newborn rat. The responses were recorded from the ventral root. Stizolobic acid and its bromo-derivatives caused a depolarizing response in a dose-dependent manner. Stizolobinic acid was considerably less potent than stizolobic acid. Depolarizing responses to stizolobic acid and its bromo-derivatives were not affected by the existence of Mg2+ and specific N-methyl-D-aspartate (NMDA) antagonists. Kynurenate depressed responses to stizolobic acid. These results suggest that stizolobic acid is a new excitatory amino acid in the mammalian central neurons which binds preferably to other receptors than the NMDA-type receptor.

Action Potentials↗

[The effect of purification procedures on the determination of serum level of 1,25-dihydroxyvitamin D].

The advance in knowledge of clinical disorders involving calcium and bone diseases has resulted in part from the development of assay procedures for the major vitamin D metabolites, but the values of the same samples measured in different laboratories vary considerably. They suggest that the chromatographic purification involved in these assays seems to be a critical step. In this study, we compared the results of 1,25-dihydroxyvitamin D (1,25(OH)2D) using different chromatographic purification methods: Sephadex LH-20 column chromatographic purification (non-HPLC method) described by Mallon et al. and High Performance Liquid Chromatographic purification (HPLC method) modified by Yamaoka et al. Serum 1,25(OH)2D levels of healthy volunteers before and after oral load of 4 micrograms of 1 alpha-hydroxyvitamin D3 (1 alpha OHD3) were measured by the two different methods mentioned above. A good correlation (r = 0.951, p less than 0.001) was noted in the samples before loading. The mean values of serum 1,25(OH)2D before loading did not differ significantly between HPLC method and non-HPLC method. After loading, however, the mean value of serum 1,25(OH)2D was significantly higher in non-HPLC method (p less than 0.01). The values of 1,25(OH)2D were determined in the serum added 1,25-dihydroxy-24-oxo-vitamin D3 (24-oxo-D3) (0 pg/ml, 200 pg/ml or 2000 pg/ml). In the samples added 2000 pg/ml of 24-oxo-D3, the mean value of 1,25(OH)2D was significantly higher in non-HPLC method (p less than 0.001). The affinity of 24-oxo-D3 for 1,25(OH)2D3 cytosolic receptor was evaluated in chick embryo intestinal mucosa and rachitic chick intestinal mucosa.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Stizolobic acid, a competitive antagonist of the quisqualate-type receptor at the crayfish neuromuscular junction.

Stizolobic acid and stizolobinic acid are amino acids isolated from a plant, Stizolobium hassjoo. Both amino acids reduced responses to glutamate and quisqualate in a competitive manner at the crayfish neuromuscular junction, without affecting responses to GABA and acromelic acid. Excitatory junctional potentials were decreased in the presence of stizolobic or stizolobinic acid in a concentration dependent manner. Stizolobinic acid was about 5 times less potent than stizolobic acid.

Amino Acids, Dicarboxylic↗

1,25(OH)2D and 24,25(OH)2D production in the developing kidney.

To clarify the state of vitamin D production by the developing kidney, firstly, we measured serum levels of 1,25(OH)2D and 24,25(OH)2D in humans of different ages (pregnant and nonpregnant women, adult males, children and newborn infants) and secondly, we measured 1 alpha- and 24-hydroxylase activity in the kidney mitochondria of rats at different ages. The mean serum levels of 1,25(OH)2D in pregnant women, cord blood and newborns were significantly higher than those in children and nonpregnant women and adult males. In newborns, the level increased with gestational age. Synthesis of 1,25(OH)2D was, at least in part, under the control of the fetus and newborn, rather then being solely a reflection of the conditions prevailing in the mother. The 1 alpha-hydroxylase activity in mitochondria was highest in the 1- to 2-month-old rats, and it decreased gradually thereafter. The change in 1 alpha-hydroxylase activity with age was due to a change in the Vmax of the system.

24,25-Dihydroxyvitamin D 3↗

Medroxyprogesterone acetate enhances spontaneous mammary tumorigenesis and uterine adenomyosis in mice.

Based on our previous findings that medroxyprogesterone acetate (MPA) significantly suppressed the formation of preneoplastic mammary hyperplastic alveolar nodules in mice, and that this suppression persisted for some time, we studied the effects of different schedules of MPA treatment on spontaneous mammary tumorigenesis and uterine adenomyosis in SHN virgin mice. Mice received a subcutaneous pellet of MPA every 2 months: I) during the limited period of 1-3 months of age; II) throughout the experiment beginning at 6-8 months of age; and III) throughout the experiment beginning at 2-3 months of age. All treatments significantly enhanced mammary tumorigenesis with little difference in the effects among treatments. The progression of uterine adenomyosis was also stimulated in Experiments I and III, but not in Experiment II. These results are in good accord with our previous observations with progesterone, indicating that MPA has progesterone-like effects on mammary and uterine lesions of mice.

Animals↗

Microcarriers facilitate mineralization in MC3T3-E1 cells.

MC3T3-E1 cells showed mineral deposits after about 1 week of culture when incubated in the presence of microcarrier beads. These deposits appeared as white spots on the dish surface, and under light microscopy the cells showed multiple cell layers and mineralization around the microcarriers. The deposits stained positive with calcium-specific Von Kossa's method. Using conventional assay, alkaline phosphatase activity (ALP) and parathyroid hormone-stimulated intracellular cAMP production were lower in the microcarrier cultures than in the control, but using cytochemical methods, high alkaline phosphatase activity was found around the microcarriers. These results indicate that microcarriers facilitated the formation of multiple cell layers and provided a culture environment for mineralization.

Alkaline Phosphatase↗