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Biomedical subjects

M Doi

Publications and source records attributed to M Doi.

At least 271 records · Page 15Linked to original sources
PubMed1991

Conformational dynamics of DNA affected by intercalation and minor groove binding: direct observation of large DNA.

Using fluorescence microscopy, we have observed moving DNA molecules in solution and analyzed the "higher-order" structure in a quantitative manner. It was found that EB (ethidium bromide), an intercalator, has the effect to increase the persistent length. In other words, EB expands DNA. Whereas, DAPI (4',6-diamidino-2-phenylindole), a minor groove binding drug, decreases the persistent length. It is demonstrated that the direct observation of DNA molecules with fluorescence microscopy is quite useful to study the interaction of various chemical compounds with DNA molecules.

Bacteriophage T4↗
PubMed1991

[A case of epidural hematoma due to dural metastasis].

A case of epidural hematoma due to dural metastasis is reported. A 62-year-old man was admitted to our hospital with generalized convulsion. A month prior, he underwent a tumor-removal operation for dural metastasis of lung cancer. CT scan on admission showed an epidural hematoma at the left frontal region. At operation, the epidural hematoma and dural invasion of neoplasm was found and removed. Pathological examination revealed dural metastasis of the poorly differentiated adenocarcinoma. According to the literature, intracranial metastasis of a bronchogenic carcinoma bleeds more often than that of other carcinomas. The particular vascular invasiveness of the neoplasm or a hemorrhagic diathesis is considered as the cause of the hemorrhage. In the present case the pathogenesis of the hemorrhage was thought to be the hypervascularity of the rapid growth tumor, fragility of the tumor vessels, and invasiveness of the tumor into the dural vessels. Adding to these, two other factors could play an important role in forming epidural hematoma; 1) the tumor existed mainly in the epidural surface and 2) dural adhesion of the cranial bone was not so tight.

Adenocarcinoma↗
PubMed1991

[A clinical study on intrathoracic malignant lymphoma with chronic tuberculous pyothorax].

The authors reported 3 male patients of malignant lymphoma developing from long-standing pyothorax. They had been suffering from tuberculous pyothorax for more than 30 years, after artificial pneumothorax therapy for pulmonary tuberculosis. The most common symptom was chest pain. It was difficult to detect the tumor mass by chest X-ray because of old inflammatory changes. Computed tomography and 67Ga scintigraphy were useful. The lesions tended to grow destroying the surrounding lung, chest wall and ribs. Histologically, 2 cases were diffuse large cell type and one was diffuse intermediate sized cell type. Immunologically, 2 cases were B-cell type lymphoma but one was not clearly classified. They received radiotherapy, but 2 cases died of respiratory failure. These findings suggest that B cell lymphoma might arise following chronic tuberculous pyothorax. Therefore such cases should be followed up carefully.

Empyema, Pleural↗
PubMed1991

[Secular trends in prevalence and incidence of atrial fibrillation and associated factors in a Japanese rural population].

To investigate secular trends in prevalence and incidence of atrial fibrillation and associated factors, data from population studies of a northeast rural Japanese community, were explored. Cross-sectional studies for men and women aged 40-69 year were conducted in 1963-1966, 1972-1975 and 1984-1987. Age-adjusted prevalence rates of atrial fibrillation show no significant change in both men and women during these three periods. Over 80% of atrial fibrillation in each period showed no clinical evidence of rheumatic valvular disease, myocardial infarction, idiopathic cardiomyopathy, congenital heart disease and hyperthyroidism. Cohorts of men and women aged 40-69 year without atrial fibrillation at baseline were constructed in 1963-1966 (1,920 persons) and in 1972-1975 (2,325 persons) and followed until 1974 and 1987, respectively. In both cohorts, incidence of atrial fibrillation without these organic diseases was positively associated with hypertension related funduscopic abnormality and urine protein. Age-adjusted incidence rates of atrial fibrillation declined in both men and women between the two cohorts. This decline which was greater in hypertensives than in normotensives may in part reflect improvements in hypertension control in this community.

Adult↗
PubMed1991

[The number and soma size of retinal ganglion cells in Chinese hamsters].

The number and somatic size of retinal ganglion cells in Chinese hamsters were examined by means of the horseradish peroxidase (HRP) staining method. The HRP staining is a method by which only the retinal ganglion cells can be stained. The number of ganglion cells per eye was 67,636-79,545 (mean: 73,575, n = 3). There was a tendency for the density of retinal ganglion cells to be larger in the central than in the peripheral retina. The diameter of retinal ganglion cells was 6-28 microns (mean: 13.0 microns, n = 500) and there was a tendency for the number of small cells to be larger in the central than in the peripheral retina.

Animals↗
PubMed1990

Molecular conformation of achatin-I, an endogenous neuropeptide containing D-amino acid residue. X-ray crystal structure of its neutral form.

The molecular conformation of achatin-I neutral form (H-Gly-D-Phe-Ala-Asp-OH), an endogenous neuropeptide, was elucidated by X-ray crystal analysis. The molecule has a type II' beta-turn structure with the D-Phe-Ala residues at the corner of the bend, which is further stabilized by two NH(Gly)...C gamma = O sigma(Asp) and NH(Asp)...C gamma = O sigma(Asp) intramolecular hydrogen bonds. This turn conformation may be an important feature of achatin-I related to its neuroexcitatory activity.

Amino Acid Sequence↗
PubMed1990

An attempt to structurally convert mu-selective morphine toward delta-receptor binding: dimerization based on enkephalin conformation.

In order to elucidate the substrate specificities for mu- and delta-opioid receptors, dimerization of the mu-specific morphine molecule was attempted, based on the hypothesis of the possible relationship between the molecular conformation of endogenous enkephalin and its selectivity for each opioid receptor. The NOR2 ([normorphine]N-CH2-CH2-N[normorphine]) thus synthesized exhibited agonist activity showing a preference for binding with the delta-opioid receptor, compared with the parent morphine molecule. Antagonist activity was also observed for NOR3 ([normorphine]N-CH2-CH2-CH2-N[normorphine]).

Animals↗
PubMed1990

Frequently repeated Fick cardiac output measurements during anesthesia.

A computer-based system was developed for monitoring cardiac output using the Fick principle during general anesthesia. The variables of the oxygen-consumption Fick equation were measured using the following system: oxygen uptake by an originally developed respiratory gas monitoring system, arteriovenous oxygen saturation difference by pulse and fiberoptic oximetry, and hemoglobin concentration by an in vitro oximeter. Fick cardiac output and systemic vascular resistance were calculated every 30 seconds. Fick cardiac output was compared with thermodilution cardiac output in 11 anesthetized patients. A total of 208 corresponding cardiac output measurements showed a range of 2 to 9 L.min-1. The correlation coefficient between the thermodilution and Fick cardiac outputs was 0.961, with a regression equation of Fick cardiac output = 1.058 thermodilution cardiac output - 0.359. The difference between the thermodilution and Fick cardiac outputs was 0.103 +/- 0.395. The Fick cardiac output was significantly lower than the thermodilution cardiac output, especially in the low flow range. We demonstrated that this new monitoring system was clinically feasible and sufficiently accurate, under the limited circumstances of our study. The integration of routinely used equipment has made possible a frequently repeatable method for estimating cardiac output in patients.

Anesthesia, General↗
PubMed1990

Beat-to-beat evaluation of cardiac function during recovery from upright bicycle exercise in patients with coronary artery disease.

The purpose of this study was to evaluate the time course of cardiac function during recovery from upright bicycle exercise in patients with coronary artery disease. Twelve patients with coronary artery disease performed a symptom-limited exercise test on a cycle ergometer. Left ventricular function was continuously monitored during exercise and recovery with a computerized cadmium telluride detector following the intravenous injection of technetium-labeled red blood cells. Although the end-diastolic volume (153.4 +/- 76.1 ml) and end-systolic volume (100.5 +/- 67.3 ml) at the end of exercise were significantly higher than the respective resting values, stroke volume (52.8 +/- 16.1 ml) and ejection fraction (38.0 +/- 12.2%) were not different from the respective resting values. The recovery of cardiac output was relatively slow compared with that of heart rate, because stroke volume rose sharply early in recovery. The rise in stroke volume was chiefly a result of a significant decrease in end-systolic volume between 1 and 4 minutes of recovery. These changes may result from an immediate afterload reduction coupled with a relatively slow decrease in sympathetic stimulation. The time course of cardiac function during recovery from exercise in cardiac patients is substantially different from that of normal subjects and may be a sensitive way to evaluate the peripheral vascular function and deteriorated cardiac function in cardiac patients.

Adult↗
PubMed1990

Prominent stacking interaction with aromatic amino acid by N-quarternization of nucleic acid base: X-ray crystallographic characteristics and biological implications.

In order to investigate the mode of interaction between the N-quarternized cytosine base and the aromatic amino acid, the crystal structure of the 3-methyl-cytidine-5'-monophosphate:tryptamine complex was analyzed by X-ray diffraction. The complex crystals were stabilized by extensive hydrogen bond formations in which eight independent water molecules per complex pair participated. A prominent stacking interaction, characterized by a parallel alignment of both rings with a separation distance of ca. 3.4 A, was observed between the cytosine base and the indole ring. Combining the present results with X-ray crystallographic data on the adenine--and guanine--aromatic amino acid interactions, we summarize the structural characteristics observed in the stacking interaction of the N-quarternized nucleic acid base with the aromatic amino acid and discuss their biological implications, especially in connection with the significance of N-protonation of nucleic acid base for selective recognition by protein.

Adenine↗
PubMed1990

Conformational characteristics of opioid kappa-receptor agonist: crystal structure of (5S,7S,8S)-(-)-N-methyl-N-[7-(1-pyrrolidinyl)-1- oxaspiro[4.5]dec-8-yl]benzeneacetamide (U69,593), and conformational comparison with some kappa-agonists.

(5S,7S,8S)-(-)-N-Methyl-N-[7-(1-pyrrolidinyl)-1- oxaspiro[4.5]dec-8-yl]benzeneacetamide (U69,593) is a potent agonist to opioid kappa-receptor. The crystal structure of U69,593 has been analyzed by the X-ray diffraction method. The molecule, as a whole, took an open conformation, and four cyclic rings composing the main skeleton were far apart from each other. The N and O atoms substituted for the cyclohexane ring were all in the equatorial position. The best planes of two 5-membered rings were almost perpendicular to that of the cyclohexane ring, and the N-methylamide linkage was also orthogonal to this ring plane. The conformation of the U69,593 molecule was compared with other kappa-agonists.

Benzeneacetamides↗
PubMed1990

Predischarge early exercise therapy in patients with acute myocardial infarction on the basis of anaerobic threshold (AT).

The aim of this study was to assess the effectiveness of an early predischarge exercise therapy, started 2 weeks following acute myocardial infarction (AMI), to working functional capacity. Seventeen AMI patients (10 males, 7 females, mean age 62 +/- 11 years) were examined in this study. Six, serious clinical symptoms and complications, were excluded, while the remaining 11 patients completed, the whole exercise therapy protocol (2 weeks). Patients performed exercise performed for 20-30 min twice daily at a target heart rate (90% level of heart rate at AT) on the basis of anaerobic threshold (AT) determined using treadmill ramp exercise with our protocol. Heart rates (HR) at rest, warming-up and AT point decreased significantly (p less than 0.05) after exercise therapy, although peak HR remained unchanged. O2 pulse at the AT point and endpoint, after exercise therapy, improved significantly (p less than 0.05), when compared to that before therapy. Moreover, AT and peak VO2 improved remarkably (p less than 0.05), as did exercise time to the AT point and endpoint after exercise therapy (p less than 0.05), when compared to that before therapy. These results indicate that the predischarge early exercise therapy begun 2 weeks after AMI will be effective and beneficial in improving working capacity with improvement of physical deconditioning. Additionally, it is necessary that patients with severe clinical symptoms and complications be excluded.

Adult↗
PubMed1990

Effects of isosorbide dinitrate on exercise capacity in cardiac patients--relationship between oxygen uptake responses and hemodynamic effects.

Acute effects of oral isosorbide dinitrate on exercise capacity were evaluated in 14 patients with chronic heart disease measuring the anaerobic threshold and left ventricular function during exercise. A symptom-limited exercise test was performed on a bicycle ergometer with work rates increased by 1W every 6 seconds. Left ventricular function was continuously monitored with a computerized cadmium telluride detector following the intravenous injection of technetium-labeled red blood cells. Thirty minutes after the control exercise test, patients were given isosorbide dinitrate, 5 mg orally. The second exercise test was performed 30 min later. Isosorbide dinitrate improved the anaerobic threshold from 715.4 +/- 172.9 to 774.9 +/- 173.5 ml/min (p less than 0.01) and ejection fraction at peak exercise from 36.7 +/- 11.6 to 39.9 +/- 12.3% (p less than 0.05). However, there was no significant change in maximum work rate or peak oxygen uptake. Those patients for whom isosorbide dinitrate resulted in a 10% or greater improvement in the anaerobic threshold had both higher pre-treatment ejection fractions and greater increases in peak exercise ejection fraction following isosorbide dinitrate. Measurements of the anaerobic threshold and left ventricular function during exercise may be useful in the evaluation of the efficacy of vasodilators in cardiac patients.

Anaerobiosis↗
PubMed1990

Trends for coronary heart disease and its risk factors in Japan: epidemiologic and pathologic studies.

Epidemiologic and pathologic studies were conducted between 1965 and 1986 to investigate trends for the incidence of coronary heart disease (CHD) and its risk factors in urban and rural populations and to relate the risk factor changes to trends for CHD incidence and pathologic findings. The epidemiologic study included men aged 40-59 years who urban residents of Osaka, clerical and manual workers in Osaka, and rural residents of Akita prefecture. The pathologic study subjects were autopsied men aged 30 and over, admitted to a local hospital in Akita, whose autopsy rate was 88%. From a cohort of 8,835 urban employees between 1975 and 1987, risk factors for myocardial infarction were identified: blood pressure, total serum cholesterol, blood glucose and cigarette smoking all which were compatible with findings in the US and European countries. For rural residents, serum cholesterol was less likely to be associated with the CHD incidence. Little contribution of serum cholesterol to development of coronary heart disease in rural men was supported by the pathologic study showing no significant association between serum cholesterol and the coronary atherosclerosis. Myocardial infarction from urban patients was characterized as massive necrosis in the myocardium with coronary artery stenosis and minimum atherosclerosis of basal cerebral arteries while that from rural men was small scattered necrosis in myocardium with atherosclerosis in both coronary and basal cerebral arteries. There was an increasing trend in the incidence of myocardial infarction in urban men but no change in rural men. The difference in the incidence trend can be attributed in part to differences in pathologic etiology and in blood pressure and serum cholesterol levels. Systematic surveillance is underway in both urban and rural population to clarify future trends for coronary heart disease and its risk factors.

Adult↗
PubMed1990

Undifferentiated carcinoma with prominent lymphocytic infiltration (so-called lymphoepithelioma) in the trachea.

This report presents a case of tracheal undifferentiated carcinoma with marked lymphocytic infiltration. The tumor was histologically similar to the so-called lymphoepithelioma of the nasopharyngeal region. After resection of the tumor, radiotherapy was performed. No recurrence has been found for six years. To our knowledge, this so-called lymphoepithelioma in the trachea is the first case reported in the literature.

Aged↗
PubMed1990

Improvement of biliary enzyme levels and itching as a result of long-term administration of ursodeoxycholic acid in primary biliary cirrhosis.

Ursodeoxycholic acid (UDCA) was administered to 10 patients diagnosed as having primary biliary cirrhosis (PBC) after liver biopsy. Eight patients were anicteric, and two were icteric cases. One patient was in stage I, seven were in stage II, one in stage I-III, and one in stage III-IV of Scheuer's classification. Six hundred milligrams of UDCA were administered orally after meals three times daily to all of the patients for more than 1 yr. The period of UDCA administration ranged from 6 to 41 months. The major findings are as follows: 1) in six out of seven patients with pruritus, itching disappeared 1 month after administration of UDCA; 2) both serum alkaline phosphatase and gamma-glutamyltranspeptidase levels began decreasing significantly the first month after the onset of UDCA treatment, and continued decreasing throughout the treatment; 3) GOT and GPT levels also decreased significantly during the administration of UDCA, compared with before-treatment levels; 4) in one icteric patient with portal hypertension, although serum biliary enzyme levels improved after treatment, serum bilirubin level got worse, and the patient died of esophageal variceal hemorrhage. In another icteric case, biliary and bilirubin levels improved slightly after treatment; 5) antimitochondrial antibody titer decreased in four cases, but IgM levels and other immunological parameters were not changed; 6) serum UDCA increased significantly during UDCA treatment; in particular, glyco-UDCA occupied up to 40% of the total bile acid and CDC decreased to 25%; 7) portal inflammation activity decreased in all five patients who had undergone follow-up liver biopsy, more than 1 yr after UDCA administration--bridging fibrosis decreased in three cases; and 8) no side effects were observed in any of the cases. Although large-scale, randomized, controlled, double-blind tests are necessary, it is speculated that the long-term administration of UDCA is a safe and effective treatment for the improvement of biliary enzyme levels and pruritus in anicteric PBC.

Adult↗
PubMed1990

[A case of nephrotic syndrome associated with small intestinal ulcers due to necrotizing angitis].

A 34-year-old man was admitted to Prier hospital because of head and right foot injuries caused by a traffic accident. Two months after admission, he complained of abdominal pain and bloody stool. Shortly after purpura appeared on both legs. He received an exploratory laparotomy and showed multiple jejunal ulcer. A pathological examination of the jejunum revealed necrotizing vasculitis of the small arteries. After the operation, he had arthralgia and the laboratory examination showed massive urinary protein. Arthralgia, abdominal pain and bloody stool disappeared with the administration of 100 mg per day of prednisolone (PSL), but nephrotic syndrome was not relieved. As a result he was referred to our hospital. And after admission, PSL was gradually tapered to 60 mg per day. Then an open renal biopsy was performed, and pathological examinations revealed focal proliferative glomerulonephritis in which 31% of the glomerulus showed fibro-cellular crescents. A direct immunofluorescence of the renal biopsy showed mesangial deposits of IgA, IgG, C3. The patient was treated with anti-coagulant therapy and PSL. Urinary protein was gradually decreased to 0.7 g/day, and his creatinine clearance was 23 ml/min five months after the renal biopsy. In this case, although the renal biopsy specimens and clinical symptoms were compatible with HSP, a pathological examination of jejunum revealed vasculitis of the small arteries. In literature, HSP is a syndrome characterized by vasculitis of arterioles, capillaries and venules. As a results of those findings, we think the diagnosis of this patient is PN with mesangial IgA depositions of renal glomeruli.

Adult↗