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Biomedical subjects

K Miyajima

Publications and source records attributed to K Miyajima.

At least 127 records · Page 7Linked to original sources
PubMed1989

Magainin 1-induced leakage of entrapped calcein out of negatively-charged lipid vesicles.

Effects of magainin 1, a novel antimicrobial peptide, on the permeability of lipid vesicles were investigated by using calcein as a trapped fluorescent marker. Magainin 1 induces the leakage of calcein specifically out of negatively-charged vesicles. The peptide binds to bovine brain phosphatidylserine sonicated vesicles according to the Langmuir isotherm with a binding constant of 3.8.10(5) M-1 and a binding-site number of 0.10 per lipid molecule. The leakage seems to occur at a critical binding number of approx. 0.03 per lipid molecule. A circular dichroism study revealed that magainin 1 conforms mainly to an unordered structure both in an aqueous solution and in the presence of egg yolk phosphatidylcholine vesicles, whereas to an amphiphilic helix with the phosphatidylserine vesicles. In conclusion, magainin 1 interacts with acidic lipids through electrostatic interactions followed by hydrophobic interactions to form an amphiphilic helix, inducing the leakage.

Animals↗
PubMed1989

A new HPLC fluorimetric method to monitor urinary delta-aminolevulinic acid (ALA-U) levels in workers exposed to lead.

A new sensitive HPLC method for the determination of urinary delta-aminolevulinic acid (ALA-U) was used to evaluate the relationship between blood-lead (Pb-B) and ALA-U levels in male workers exposed to lead. The differences between the ALA-U levels determined by this method (ALA-U-HP) and by a colorimetric method (ALA-U-CL) are discussed. The HPLC method gave values similar to the ALA-U-CL values at high ALA-U level. However, at low blood-lead levels (58 +/- 22 micrograms/l, n = 23), the mean ALA-U-HP level corrected by urinary creatinine level was one-third of the corrected ALA-U-CL level (0.83 +/- 0.14 and 2.4 +/- 0.5 mg/g creatinine, respectively). A significant increase of the mean corrected ALA-U-HP level was observed at 162 +/- 22 micrograms/l Pb-B (P less than 0.05, n = 26), while that of ALA-U-CL was observed at 245 +/- 30 micrograms/l Pb-B (P less than 0.01, n = 37). The regression equation based on the logistic model fitted well to the relationship data between the Pb-B level and the percentage of the subjects with corrected ALA-U-HP above the cut-off point (1.12 mg/g creatinine) and the expected Pb-B level for 50% response was 270 micrograms/l Pb-B, while it did not fit well to the relationship data between Pb-B level and the percentage of the subjects with corrected ALA-U-CL above the cut-off point (3.5 mg/g creatinine).(ABSTRACT TRUNCATED AT 250 WORDS)

Aminolevulinic Acid↗
PubMed1989

Effect of the interaction of drug-beta-cyclodextrin complex with bile salts on the drug absorption from rat small intestinal lumen.

This investigation was concerned with the change of the bioavailability of a drug owing to the interaction of the drug-beta-cyclodextrin complex with bile salts in rat intestinal lumen. The absorption of sulfamethizole (SMZ) from rat intestinal lumen after administration of SMZ-beta-cyclodextrin complex was determined by a closed-loop method in the presence or absence of bile. The blood level of SMZ after administration of SMZ-beta-cyclodextrin complex was significantly decreased in comparison with that after administration of SMZ alone in bile duct-ligated rats. On the other hand, the blood level of SMZ after SMZ-beta-cyclodextrin administration in intact rats (bile duct non-ligated) or on the addition of sodium cholate was similar to the level in the case of SMZ alone. Thus, bile salts were found to act as a competing agent in the gastrointestinal tract.

Animals↗
PubMed1989

Root resorption.

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Calcium Hydroxide↗
PubMed1989

Choleretic effects of ursodeoxycholic acid on experimentally-induced intrahepatic cholestasis.

When a lymphokine, the cholestatic factor, is intravenously injected into rats through a mesenteric vein, remarkable reductions in bile flow and bile acid excretion are observed. Using this experimentally-induced intrahepatic cholestasis model, the choleretic effects of ursodeoxycholic acid (UDCA) were studied. When UDCA was injected with the cholestatic factor, the reductions in bile flow and bile acid excretion were significantly suppressed. Remarkable choleretic effects were also noted, when UDCA was administered to normal rats. These results suggested that UDCA may be effective in the treatment of intrahepatic cholestasis.

Animals↗
PubMed1989

[Efficacy of home exercise program in a convalescent phase of acute myocardial infarction evaluated by Borg's indices, expiratory gas analysis and blood lactate].

The Borg's indices, the rate of perceived exertion have been widely accepted to evaluate subjective symptoms semi-quantitatively in exercise tests. We applied the indices to evaluate the efficacy of our home exercise program in patients with acute myocardial infarction. Eighty-five patients were entered in our home exercise program after their discharge from the hospital. This program consisted of everyday 2 km walk-jog exercise for 1 month keeping their heart rate at 100-110/min during the exercise. Before and 1 month after their discharge, they underwent treadmill exercise tests with expiratory gas analysis and a measurement of blood lactate. In the treadmill tests performed before and after the training, VO2 and heart rate increased linearly with Borg's indices, however VE and blood lactate had disproportionate increases after Borg's 13 which is considered to be the anaerobic threshold (AT). In fact, AT measured individually by expiratory gas analysis and blood lactate, appeared at Borg's 13 in 53% of the patients. After 1 month physical training, VO2 and heart rate significantly increased at the same Borg's indices, but there was no significant changes in blood lactate at the same Borg's score before and after the training. These results suggest that, in patients with acute myocardial infarction, exercise performance significantly increased at any score of subjective symptoms and that Borg's indices may reflect the blood lactate levels. It is concluded that Borg's indices, closely related to the dynamics of blood lactate, are not only useful in quantifying subjective symptoms but also to estimate the efficacy of physical training.

Adult↗
PubMed1989

[Development of mandibular movements associated with growth and development of stomatognathic system].

In order to clarify the development of mandibular movements associated with growth and development of the stomatognathic system, we compared the mandibular movements of children with normal occlusion at different Hellman's dental age between IIA and IIIB, during tooth tapping movements using the following 7 different kinds of frequency; ad lib.; 1 time/sec, 2 times/sec and 3 times/sec movements with reguration; 1 time/sec, 2 times/sec and 3 times/sec movements without reguration. Then, we determined the correlation between the results and the subjects' chronological age and obtained the following findings. 1) During 5 strokes between the 3rd and 7th strokes after the start of the tooth tapping movements, mandibular movements were not very diversified among 30 tooth tapping movements using the 7 different kinds of frequency, and the mean values were almost consistent. 2) In the 5 strokes between the 3rd and 7th strokes at all dental age, each determined item showed minimal dispersion during the 3 times/sec unregurated movements. 3) In the following items, changes related to age were noted during the 3 times/sec unregurated movements. (1) Cycle time decreased and became closer to the calculated value (333.33 msec), and maximum velocity in closing increased as age advanced. (2) Although there was no significant correlation with the subjects' chronological age, degree of mandibular opening, duration of opening phase, duration of closing phase, duration of occluding phase and velocity peak time in opening decreased, and maximum velocity in opening increased as age advanced. (3) Velocity peak time in closing was only slightly influenced by age. 4) These results indicate that mandibular movements develop in the course of growth and development of the stomatognathic system.

Humans↗
PubMed1988

Experimental immunological intrahepatic cholestasis model.

Heat-killed Propionibacterium acnes (P. acnes) was intravenously injected into tuberculin-sensitized guinea pigs, and 7 days later, purified protein derivative (PPD) was also injected intravenously resulting in marked reductions in bile flow and bile acid excretion. Serum levels of bile acids and cholesterol were increased, and the activities of alkaline phosphatase (ALK-p) and leucine aminopeptidase (LAP) were also elevated. Histological examination revealed dilatation of bile canaliculi and diminution of microvilli. These results indicated that intrahepatic cholestasis was induced. These pathological changes were not detected in guinea pigs in which PPD was not injected. In this experimental model, the tuberculin-sensitized lymphocytes were infiltrated into the liver by P. acnes injection and the cholestatic factor was produced by PPD injection, resulting in the induction of intrahepatic cholestasis.

Animals↗
PubMed1988

Isolation and characterization of carp prolactin.

Prolactin (PRL) was extracted with acid-acetone from common carp (Cyprinus carpio) pituitary glands and purified by gel filtration on Sephadex G-75, ion-exchange chromatography on DEAE-cellulose, and reversed-phase high-performance liquid chromatography (HPLC) on TSK-gel TMS 250 with a yield of 0.7 mg/g wet tissue. At each stage of purification, fractions were monitored by HPLC on TSK-gel ODS 120T and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Carp PRL was almost equipotent with ovine PRL in retaining plasma Na concentrations in the hypophysectomized killifish, Fundulus heteroclitus. Immunocytochemistry at both the light and electron microscopic levels revealed that carp PRL antiserum specifically stained cells in the goldfish rostral pars distalis. No cross reaction with putative growth hormone (GH) cells in the proximal pars distalis was observed. The specificity of the carp PRL antiserum was confirmed by immunoblot studies. Although immunostaining of both carp and salmon PRL was observed, there was no cross reaction to GHs from these species. Carp PRL had a sole N-terminal residue of valine, a molecular weight of 23 kDa in SDS-PAGE, and an isoelectric point of 7.3 by gel electrofocusing. Based on these results, together with the knowledge of physicochemical properties of salmon and tilapia PRLs, we propose a standard procedure for isolation of fish PRLs.

Animals↗
PubMed1987

Detection of the cholestatic factor in the liver tissue of patients with acute intrahepatic cholestasis.

A novel lymphokine, which we have designated as cholestatic factor (CF), was produced from peripheral blood lymphocytes of patients with drug-induced allergic intrahepatic cholestasis by stimulation with a causative drug in the presence of the liver soluble fraction containing liver-specific lipoprotein (LSP). Marked reductions in bile flow and bile acid excretion were induced in rats by injecting CF through a mesenteric vein. In order to confirm the presence of CF in the liver tissue of patients, we attempted to detect this lymphokine by using the enzyme-labelled antibody method. As a result, CF was found in the liver tissue of eleven out of thirty-eight patients with acute intrahepatic cholestasis including one with hepatitis A type, one with hepatitis B type, two with hepatitis non-A non-B type, five with drug-induced allergic hepatitis, one with alcoholic hepatitis and one with lupoid hepatitis. In contrast, CF was undetectable in the liver tissue of patients without intrahepatic cholestasis. These results may additionally support our assumption that CF plays an important role in the induction of intrahepatic cholestasis in various liver diseases.

Acute Disease↗
PubMed1987

[Tricuspid regurgitation evaluated by intraoperative epicardial pulsed Doppler echocardiography: investigation of patients with combined valvular diseases].

To evaluate the grade of tricuspid regurgitation (TR) associated with mitral valve disease and to ascertain the operative procedure for the involved tricuspid valve, epicardial pulsed Doppler echocardiography (PDE) was performed during cardiac surgery. Thirty-two patients with mitral valve disease were studied, 17 of whom had only mitral valve lesion; the remaining 15 had combined mitral and aortic valve disease. The patients' ages ranged from 24 to 63 years and averaged 48.3 years. There were nine men and 23 women. Echocardiographic examinations were performed using a Toshiba SSH-60A for parasternal study and a SSH-11A combined with a SDS-10A with a specially-devised flat transducer for intraoperative use. Intraoperatively, the PDE performed was from the right side of the right atrium (RA), referenced by a four-chamber view and a long-axis view of the right ventricular inflow. The sampling volumes were positioned in the inflow of the right ventricle, immediately above the tricuspid valve, the middle and upper areas of the RA, and adjacent to the interatrial septum. PDE was performed before and immediately after the operative procedure and before chest closure. By severity, TR was classified as non -, mild +/-, moderate +, and severe ++, according to the distances attained by the TR signals from the tricuspid valve orifice, and the velocities and durations of the TR signals during systole. The TR signal was recorded in 23 of 32 patients before surgery, whereas it was determined more adequately in 28 patients by intraoperative epicardial PDE. The gradings of TR via the parasternal approach before surgery were as follows: no TR, in nine cases; mild TR, in three; moderate, in 13; and severe, in seven. Intraoperatively, four patients had none; eight had mild TR; 14, moderate TR; six, severe TR before surgical intervention, respectively. In cases with mild or no TR before surgery, TR was rarely detected by contrast echocardiography using saline solution injected into the right ventricle during surgery. The moderate or severe cases before surgery had moderate or severe TR according to the contrast method during surgery, except for one case not operated on for tricuspid valve disease. Tricuspid valve replacement was performed for two patients, and tricuspid annuloplasty or valvuloplasty for eight.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗