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Biomedical subjects

M Asao

Publications and source records attributed to M Asao.

At least 19 recordsLinked to original sources
PubMed1999

Mutation and DNA modification in Salmonella exposed to N-nitrosodimethylamine under UVA- and sunlight-irradiation.

Previously, we reported that when Salmonella typhimurium and Escherichia coli were treated with N-nitrosodimethylamine (NDMA) under irradiation with ultraviolet-A (UVA), mutagenesis of the bacteria took place without externally added activation enzymes. We also observed the formation of O(6)-methylguanine (O(6)-meG), N(7)-methylguanine (N(7)-meG) and 7,8-dihydro-8-oxodeoxyguanosine (8-oxodG) in calf thymus DNA treated with NDMA plus UVA. In this study, we observed the mutagenicity of NDMA under irradiation of natural sunlight in S. typhimurium. Furthermore, we detected the formation of O(6)-meG, N(7)-meG and 8-oxodG in calf thymus DNA treated with NDMA plus simulated sunlight. Regarding the mutagenesis of S. typhimurium by NDMA plus UVA, we have now identified and quantified O(6)-meG formed in the genomic DNA of the bacteria under conditions of the mutagenesis.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed1999

3D-pharmacophore analyses of aldose reductase inhibitory spiroquinazolinones.

In order to get an insight for designing novel inhibitors of aldose reductase, we analyzed relationships between structures of spiroquinazolinones and their inhibitory activities against rabbit aldose reductase by comparative molecular field analysis and molecular modeling of the enzyme-inhibitor complex. It was revealed that the following interactions were operative for the enhancement of inhibitory activity; 1) the hydrophobic interaction between substituents at the 6'- and 7'-position of quinazolinone and the hydrophobic residues such as Trp20, Val47, Tyr48, Tyr121 and Phe122; 2) the electrostatic interaction formed between electronegative substituents at the 6'-position and the side chain of Gln49; 3) the complementary fit of sterically small 6'-substituents to the active site.

Aldehyde Reductase↗
PubMed1998

[New coronary artery lesions in patients with ischemic heart disease].

The appearance of a new coronary artery lesion is important in patients with acute myocardial infarction or late coronary artery bypass grafting surgery, which sometimes lead to cardiac death. We studied coronary angiograms of 1,098 patients with coronary artery disease (from 1985 to 1996) and found new lesions in 94 patients (male 74, female 20; mean age 61.6 years). Mean observation period of all 1,098 patients was 50.1 +/- 30.4 months, and that of patients with new lesions was 73.2 +/- 31.2 months. Clinical findings of the 94 patients were acute myocardial infarction (n = 28), recurrent angina (n = 56), and silent ischemia (n = 10). The appearance of a new coronary lesion was found in 2.4% (1992), 1.9% (1993), 2.3% (1994), 1.7% (1995) of all patients with ischemic heart disease per year. The new lesions were found more often in patients with non-significant stenotic lesions (n = 74) than in patients with lesions of > or = 50% stenosis (n = 20). Complex lesions were found in 56% of the recurrent angina group, and in 22% of the silent ischemia group. In our study, the rate of appearance of new coronary artery lesions was much lower than in Europe or the United States of America. These results require careful consideration for coronary revascularization procedures in Japanese patients.

Angina Pectoris↗
PubMed1996

Characterization of the constituent polypeptides of the extracellular hemoglobin from Lumbricus terrestris: heterogeneity and discovery of a new linker chain L4.

The extracellular hemoglobin of Lumbricus terrestris comprises four oxygen binding chains, a, b, c, d, and three linker chains L1, L2, L3 as major components. A stoichiometry of the whole molecule has been proposed on the basis of these chains, with a total number of 216 chains: forty-eight chains of each oxygen binding chain and eight molecules of each linker chain. We have isolated additional minor components by HPLC and two-dimensional gel electrophoresis. The following biochemical characterizations have been made. (i) All components so far reported, the heme-containing chains a, b, c, d, and linker chains L1, L2, L3 and a new minor polypeptide, L4, were mapped on a two-dimensional gel. Their estimated isoelectric points were between 4.7 and 5.9. (ii) The sequences of several peptides including the unique N-terminal peptide from linker L4 show that it can be considered as a duplicated gene product with a similar mass. (iii) Chain d2 was isolated and found to correspond to the minor chain previously pointed out by Shishikura et al. (J. Biol. Chem. 262 (1987) 3123-3131). (iv) The major chain d1 has serine at position 7 from the N-terminus. This is not consistent with previously reported glycine (Shishikura et al., J. Biol. Chem. 262 (1987) 3123-3131).

Amino Acid Sequence↗
PubMed1992

Biological activities and quantitative structure-activity relationships of spiro[imidazolidine-4,4'(1'H)-quinazoline]-2,2',5(3'H)-triones as aldose reductase inhibitors.

A series of spiro[imidazolidine-4,4'(1'H)-quinazoline]- 2,2'5(3'H)-triones were prepared and tested for aldose reductase inhibitory activity. The 6'-halogenated derivatives were found to be highly potent in vitro inhibitors of male rabbit lens aldose reductase and in vivo inhibitors of polyol accumulation in the sciatic nerves of galactosemic rats. Of these, (4R)-6'-chloro-3'-methylspiro[imidazolidine-4,4'(1'H)-quinazoline] -2,2',5(3'H)-trione (67) showed the most potent in vitro and in vivo activities. An oral dose of 3 g/kg of compound 67 caused neither death nor behavioral abnormality in the preliminary acute toxicity study using mice and rats. Compound 67 was selected as a candidate for further evaluation. The quantitative structure-activity relationships in this series are also discussed.

Aldehyde Reductase↗
PubMed1992

[The effects of intracoronary injection of nitroglycerin on the coronary circulation: evaluation using a Doppler catheter].

To evaluate the effects of intracoronary injection of nitroglycerin (NTG) on the coronary circulation, we measured the flow velocity of the coronary artery using a Doppler catheter. The Doppler catheter was introduced into the region proximal to the left anterior descending artery (LAD) via an 8F guide catheter positioned at the orifice of the left coronary artery. We measured the flow velocity at a point of 3 mm distal to the catheter tip. One mg (2 ml) of NTG was injected via the 8F guide catheter for 10 sec, followed by injection of 3 ml of normal saline. Then the increasing rate of the diastolic coronary flow velocity in the LAD was calculated. Five ml of iopamidol (dye) was also injected for comparison. The subjects consisted of 14 normal persons (G-N), and 12 patients with angina pectoris accompanying critical stenoses of the LAD, who had no ECG changes or no abnormalities by left ventriculography. The subjects with angina pectoris were subclassified as 90% stenoses (G-A: 5 patients), and 99% stenoses (G-B: 7 patients) in the LAD. 1. After intracoronary injection of NTG, the aortic pressure dropped to various degrees in G-N. In 7 of the normal subjects, who had less than a 20% aortic pressure drop, the increased diastolic flow velocity was more rapid than the control diastolic flow velocity 30 sec after the peak velocity.(ABSTRACT TRUNCATED AT 250 WORDS)

Angina Pectoris↗
PubMed1992

[Treatment of postoperative mediastinitis using an omental pedicle flap].

Four patients with postoperative mediastinitis who were treated by omentopexy at the Fukuoka University Hospital between 1989 and 1990. Three of the 4 patients healed successfully, another one died of multiple organ failure 83 days after surgery. All patients were received coronary artery bypass surgery harvesting a left internal thoracic artery for ischemic heart disease. Three patients had diabetes mellitus, one patient had renal failure preoperatively. Recognition of mediastinitis was made by sternal wound purulent discharge and sternal dehiscence. Culture of the discharge fluid yielded methicillin-resistant Staphylococcus aureus in three, and Enterococcus cloacae in one. Irrigation with popidone-iodine or blonopol were ineffective. Thus, the wound was treated with debridement and omentopexy with an omental pedicle flap, respectively. Postoperative course after omentopexy were excellent, had no complications. We conclude that the omentopexy is useful in the treatment of postoperative refractory anterior mediastinitis.

Aged↗
PubMed1992

[Successful surgical treatment by Konno aortoventriculoplasty in 2 cases of congenital aortic valvular stenosis].

Konno's aortoventriculoplasty was performed in two children aged 6 years and 10 years old with congenital aortic valvular stenosis. One had previous aortic valvotomy at 21 days of age. Preoperative peak systolic pressure gradients between the left ventricle and the aorta were 120 and 140 mmHg, respectively. The original diameter of the aortic valve ring were 12 mm and 16 mm and one had supra-annular aortic stenosis whose diameter was 7 mm. The 19 mm and 23 mm SJM prosthetic valves were inserted in the subcoronary position. The postoperative course was uneventful. Their ECG showed sinus rhythm with complete right bundle branch block. Both two patients made good recovery regarding clinical data and symptoms.

Aorta↗
PubMed1991

[A case of bilateral phrenic nerve paralysis following open heart surgery].

Coronary artery bypass surgery was performed on a 58-year-old female under cold cardioplegia with topical ice slush cooling. Bilateral phrenic paralysis was observed postoperatively, in spite of prevention with a mat during aortic cross clamp, cold injury owing to ice slush was thought to be causative. Mechanical ventilatory support continued for more than two months until her complete recovery of diaphragmatic function. She complained of sleeplessness besides respiratory symptoms, and felt uneasy. Although cold injury is mostly reversible, it is stressed that we must deliberately wean from mechanical ventilatory support, turning our attention to symptoms and blood gas analysis with as much mental assistance as possible.

Coronary Artery Bypass↗
PubMed1991

[Two cases of postoperative erythroderma--clinical and pathological investigation].

Two cases of postoperative erythroderma, considered the Graft-Versus-Host disease like syndrome following blood transfusion during open heart surgery, were reported. In one, a 74-year-old female underwent the patch closure of ventricular septal perforation complicated with acute myocardial infarction, and in the other, a 67-year-old female underwent coronary artery bypass surgery. They had sudden fever, general eruption, liver dysfunction, leucopenia and thrombocytopenia, and died on the 15th and the 21st days after operation. In both, pathologically, eosinophilic necrosis was seen in agreement with basal cells and prickle cells on the epidermis. T-cells and monocytes widely infiltrated on the upper dermis, particularly around blood vessels. Furthermore, similar to on the skin, cellular infiltration and eosinophilic necrosis were seen on the esophageal mucosa. Various immunoglobulin-positive cells were seen on the dermis and the esophageal mucosa, but it is not clear that this is characteristic or not, because secondary infection possibly existed on them.

Aged↗
PubMed1990

[Tachycardia-induced cardiomyopathy: a case report].

A 30-year-old man with chronic sustained ventricular tachycardia (VT) lasting more than seven years was treated with propranolol, 30 mg/day. This resulted in controlled cardiac rates of 90 to 130/min during sleep, and 100 to 195/min while awake. However, he experienced Adams-Stokes attacks twice, in September and December, 1986. During the second attack, ambulatory heart monitoring showed his VT rate of 212/min. An electrophysiological study revealed that the VT focal point was in the lower-mid region of the interventricular septum in the right ventricle. The VT was characterized by abnormal enhanced automaticity. This VT could not be interrupted either by single or multiple combinations of antiarrhythmic drugs. Cardiac catheterization revealed a diffusely enlarged hypokinetic left ventricle, even at the rate of 120/min VT (EF 27%, C.I. 2.3 l/min/m2). Because of his severe hemodynamic state, we performed electrical catheter ablation successfully. After the ablation, his left ventricular wall motion gradually improved. Nine months after the ablation, his left ventricular diastolic dimension decreased from 64 to 48 mm and the left ventricular systolic dimension decreased from 57 to 28 mm on M-mode echocardiography, while ejection fraction increased from 27 to 73% on the left ventriculography. Bi-ventricular myocardial biopsy specimens obtained prior to the ablation revealed only cellular hypertrophy of varying degrees, and vacuole degeneration consistent with non-specific cardiomyopathy. However, nine months after the ablation, these findings were no longer present. Thus, this case was considered tachycardia-induced cardiomyopathy initiated by VT, lasting many years.

Adult↗
PubMed1990

[Continuous infusion of prostaglandin E1 facilitates weaning from cardiopulmonary bypass].

Vasodilators expedite the rewarming process and facilitate weaning from cardiopulmonary bypass (CPB). We continuously infused prostaglandin E1 (PG-E1) at 0.02-0.05 microgram.kg-1.min-1 (n = 11) or phentolamine (PHENT) at 5-10 micrograms.kg-1.min-1 (n = 13) during rewarming from mild hypothermic CPB. Rectal temperature was 33.3 +/- 1.7 degrees C in PG-E1 group vs. 31.3 +/- 1.3 degrees C in PHENT group at 30 minutes, and 34.0 +/- 1.2 degrees C vs. 32.7 +/- 1.1 degrees C at 40 minutes from the start of rewarming. There were significant differences (P less than 0.01 at 30 min, P less than 0.05 at 40 min) in rectal temperature between the two groups. There were no differences in perfusion index of CPB, arterial perfusion temperature, mean arterial pressure, systemic vascular resistance as well as esophageal, forehead or palm skin temperatures at any point between the two groups. The required time for weaning from CPB was significantly shorter in PG-E1 than in PHENT group (P less than 0.01, 36 +/- 8 min vs. 46 +/- 11 min). Our results also strongly suggest that PG-E1 preferentially improves splanchnic blood flow.

Alprostadil↗
PubMed1990

[Surgical results of high grade constriction of tricuspid annulus in DeVega technique for secondary tricuspid regurgitation].

Sixty-six patients were operated on by our high degree constriction technique using DeVega tricuspid annuloplasty from 1985 to 1989. They were 20 men and 46 women, age distributed from 28 to 71 (mean 54.5). Preoperative tricuspid annular diameter ranged from 29 mm to 45 mm, average 36.3 mm. Those were constricted to 27 mm in 38 patients, and to 25 mm in 28 patients. Postoperative residual tricuspid regurgitation was observed in only 8.5% of total cases followed up 14 to 55 months. This results were comparable with other reports. We concluded that our tight constriction DeVega method is considered better to prevent postoperative tricuspid regurgitation than ordinary methods.

Adult↗
PubMed1987

Quantitative structure-activity relationships of the bitter thresholds of amino acids, peptides, and their derivatives.

Bitter thresholds of a total of 93 amino acids, peptides, and their derivatives were analyzed quantitatively by use of hydrophobicity parameters reported for amino acid side chains and those for the whole molecules estimated from partition coefficients obtained experimentally. We also explored the steric parameters that best explained the variation in the intensity of bitterness attributable to the molecular shape. The results showed that the total length along the zigzag peptide backbone chain of the molecule is an important factor. The bitterness of nonzwitterionic N-acyl and ester derivatives and that of neutral N-acyl ester derivatives were expressed by a single, common equation together with those of zwitterionic amino acids and peptides. Thus the interaction via the charge with the receptor site was probably not an indispensible factor for triggering of the bitter sensation. This study, together with earlier ones, may serve as a prototype of approaches toward unraveling structure-activity relationships of complex molecules like amino acids, peptides, and their derivatives that are of medicinal or agricultural importance.

Amino Acids↗
PubMed1986

Scimitar syndrome with an accessory diaphragm and an absent right superior vena cava.

An 8-year-old boy with scimitar syndrome, an accessory diaphragm and an absent right superior vena cava, underwent surgery on March 28, 1983. The scimitar vein was separated from an accessory diaphragm and cut just above the right diaphragm where the vein penetrated. The vein was re-implanted into the right lateral portion of the right atrium and a tunnel was made between the atrial septal defect created in the septum and the site of the implanted vein. The accessory diaphragm was not removed because of the lack of compression on the right lung. At cardiopulmonary bypass, venous cannulae were inserted into the persistent left superior vena cava and inferior vena cava. Because of the absence of the right superior vena cava, the right atrium was not fixed by both cavae so that there was difficulty in intracardiac maneuvers. The patient is doing well 32 months after this treatment.

Child↗
PubMed1985

[A successful transcatheter embolization with occluding spring emboli for vertebral arteriovenous fistulas following insertion of Swan-Ganz catheter].

Vertebral arteriovenous fistulas caused by insertion of percutaneous monitoring catheter through internal jugular vein are rare complications. This is a case report of a successful treatment by transcatheter embolization using spring occluder for the fistulas. Particular attention should be paid to the following: Normal basilar and contralateral vertebral arteriograms are prerequisites to this procedure in order to avoid its potential neurological hazards. For the complete elimination of the fistulas with retrograde filling, embolic material should be placed in the artery not only proximal but also distal to the fistulas opening.

Arteriovenous Fistula↗