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Biomedical subjects

M Kai

Publications and source records attributed to M Kai.

At least 73 records · Page 4Linked to original sources
PubMed1999

EMG activity of the muscles of the neck and forelimbs during different forms of locomotion.

We recorded the electromyographic (EMG) activity of 7 skeletal muscles in the forequarters and 1 in the hindquarters of 6 Thoroughbred horses during overground walking, swimming in a circular pool, and walking and trotting in a water treadmill. Bipolar fine wire electrodes were inserted into the muscles and the EMG signals were recorded using a telemetric system. The splenius exhibited tonic EMG activity during swimming. The brachiocephalicus showed its highest intensity during swimming followed by the walk and trot in the water treadmill and then walking overground. The triceps brachii caput longum had a similar activity pattern to the brachiocephalicus. The brachialis showed only weak EMG activity in all 3 types of locomotion. The extensor digitorum communis had higher intensity of EMG activity in the walk in the water treadmill than in other kinds of locomotion. The flexor digitorum profundus exhibited the most intense EMG activity during swimming. These results indicated that swimming evoked strong EMG activity in the antigravity muscles in spite of reduced gravitational force. Walking in the water treadmill may require more intensified EMG activity of the forelimb than the trot in the same treadmill.

Animals↗
PubMed1999

Plasma adrenocorticotropin, cortisol and catecholamines response to various exercises.

The responses of plasma adrenocorticotropin (ACTH), cortisol, noradrenaline and adrenaline in 5 Thoroughbred horses to an incremental exercise and 2 relative workload exercises, at 105 and 80% maximal oxygen consumption (VO2max), on a treadmill were examined. These hormone concentrations increased (P < 0.05) with each exercise and the maximal plasma concentrations of ACTH, cortisol were observed between 5 and 30 min after the end of the exercise, while maximal catecholamine concentrations occurred just at exhaustion time. The plasma ACTH, noradrenaline and adrenaline responses during exercise were more sensitive to the intensity of exercise than that of cortisol and showed a significant correlation with blood lactate concentrations (r = 0.605, P < 0.001 for ACTH; r = 0.718, P < 0.001 for noradrenaline; r = 0.738, P < 0.001 for adrenaline). The plasma cortisol response appeared to be connected with the duration of exercise (r = 0.71, P < 0.05). The recovery of these hormones was related to the exercise styles. These results suggest that the autonomic nervous system and the pituitary-adrenal axis of the horse are efficiently stimulated by various treadmill exercises, and these hormones may be used in the evaluation of exercise-induced stress.

Adrenocorticotropic Hormone↗
PubMed1999

Effects of caffeine and promazine hydrochloride on plasma catecholamines in thoroughbreds at rest and during treadmill exercise.

Our aim was to investigate plasma catecholamine responses to so-called 'doping' drugs and exercise in Thoroughbreds. Plasma adrenaline (Ad) and noradrenaline (NA) were determined after the administration of caffeine and promazine hydrochloride (PRZ) using a high performance liquid chromatographic method. Caffeine or PRZ was administered i.m. to Thoroughbreds and its effects on plasma catecholamines at rest and during exercise were compared with the saline control. The treadmill exercise was performed 1 h after administration. A dose of 5.0 mg/kg bwt caffeine was found to significantly increase both plasma Ad and NA levels but this was not the case for the 2.5 mg/kg bwt dose and their peak levels at 1.5 h were about 3 and 2.5 times as compared with the control values at 1.5 h (Ad: mean +/- s.e. 21.2 +/- 2.8 pg/ml, NA: 55.5 +/- 4.1 pg/ml), respectively. Both 1.0 and 1.5 mg/kg bwt PRZ doses reduced the plasma Ad to below the detection limit (10 pg/ml) and significantly reduced the plasma NA. The 2.5 mg/kg bwt caffeine dose significantly increased plasma Ad and NA during exercise and approximately doubled their maximal values as compared with the saline control (Ad: mean +/- s.e. 12.328 +/- 4.733 ng/ml, NA: 9.997 +/- 4.146 ng/ml). The 1.5 mg/kg bwt PRZ dose decreased the plasma Ad during exercise but the effect was not significant. On the other hand, PRZ significantly increased the plasma NA as compared with the saline control. In conclusion, the present study demonstrates that the plasma catecholamine responses to caffeine and PRZ were modified by exercise. It is probable that the modification may be related to exercise-induced activation of the sympathetico-adrenal axis.

Animals↗
PubMed1999

Fragility of red cells during exercise is affected by blood pH and temperature.

We examined the relationship in horses between osmotic fragility of erythrocytes (OFE) measured as the red cell haemolysis rates (HLR) in 0.56% NaCl and certain physiological characters. Animals were exercised on a treadmill: warmed up at 30% VO2max for 5 min or at 105% VO2max for 1 min, given an exercise test at 80 or 105% VO2max until fatigued, and then cooled down. The pH and temperature of the blood had a significant correlation for the HLR: r = 0.93 and 0.92 (P < 0.01) on arterial and mixed venous blood, respectively. In multiple regression analysis, heart rate and packed cell volume showed lower coefficients for the HLR. The present study suggested that, in exercising horses, 1) the increase of blood flow and release of erythrocytes from the spleen into the circulation have little effect on changes of OFE; 2) the decrease of blood pH promotes OFE; 3) the increase of the pH causes osmotic resistance in the cells and 4) an increase of blood temperature during exercise is associated with the decrease in the OFE.

Animals↗
PubMed1999

No-touch isolation technique reduces intraoperative shedding of tumor cells into the portal vein during resection of colorectal cancer.

BACKGROUND: The mutant-allele-specific amplification (MASA) method is capable of detecting 1 genetically altered tumor cell among thousands of normal cells. The MASA enabled us to detect occult tumor cells undetectable by histopathologic examination of lymph nodes and blood samples. METHODS: To investigate whether tumor manipulation during operation enhances cancer cell dissemination into the portal vein with use of MASA and to assess the effect of the no-touch isolation technique in the treatment of colorectal cancers, 27 colorectal cancers (17 were operated on conventionally and 10 were operated on according to the no-touch isolation technique) were screened for mutations in K-ras or p53. We next examined blood samples of the portal vein collected before, during, and after manipulation of tumors, using MASA to look for the specific mutation found in the primary tumors. RESULTS: Somatic mutations were identified in 18 of these primary tumors (11 were in the conventional resection technique group and 7 were in the no-touch isolation technique group). In 8 of 11 (73%) conventional resection technique cases, we identified the same genetic alteration of the primary tumor in the portal blood during operation, whereas only 1 patient (14%) in the no-touch isolation technique group had a positive result. CONCLUSIONS: The no-touch isolation technique may be useful to prevent cancer cells from being shed into the portal vein during surgical manipulation.

Alleles↗
PubMed1999

Muscle adaptation of Thoroughbred racehorses trained on a flat or sloped track.

OBJECTIVE: To determine histochemical and biochemical properties of muscle during adaptation to training on a flat or sloped track. ANIMALS: 22 Thoroughbreds. PROCEDURE: Samples were obtained from the middle gluteus muscle before and after training programs were conducted, using a needle-biopsy technique. Training programs consisted of horses running 1,600 m on a flat or sloped track for 16 weeks. Amplitude of middle gluteus muscle activity per burst was calculated. Muscle fiber composition and area were examined on serial cross sections processed by standard histochemical staining procedures (ATPase stain after prior incubation with an acid or base, followed by succinate dehydrogenase [SDH] stain). Furthermore, SDH and phosphofructokinase activities were determined biochemically, and composition of myosin heavy chain (MHC) isoforms was analyzed electrophoretically. RESULTS: Training resulted in substantial adaptations. Relative contribution of muscle fiber with high SDH activity (type-I and -IIa fibers) to total cross-sectional area, SDH activity, and composition of MHC-IIa isoforms were increased. Gel electrophoresis revealed a large amount of MHC-IIx isoform and a small amount of MHC-IIb isoform in the muscle. Although root mean square of muscle activity for training on a sloped track was 7.6% higher than the value obtained while training on a flat track, muscle histochemical and biochemical properties did not differ significantly between groups training on flat and sloped tracks. CONCLUSIONS: Training adaptations for contractile and metabolic properties of the middle gluteus muscle were evident for the 2 types of training. However, training adaptations did not differ significantly between groups trained on flat or sloped tracks.

Adaptation, Physiological↗
PubMed1999

Quantitative and qualitative analysis of stain color using RGB computer color specification.

OBJECTIVE: To establish standardized Papanicolaou stain for cytology using RGB color specification. This new method was formerly used in DTP software application for computer color specification. STUDY DESIGN: RGB color specification was taken from a color film, optical constituents of which were made into computer software. Cell samples used in this study were from 100 sputum specimens stained with Papanicolaou stain. We analyzed the color tone of the cytoplasm of squamous cells in the smear. RESULTS: The R and B value of eosinophilic cells were demonstrated statistically by different values between normal, borderline atypical and malignant squamous cells. G and B values of light green-philic cells demonstrated a statistical difference between normal, borderline atypical and malignant squamous cells. No significant differences were found in RGB value between normal, borderline atypical and malignant squamous orangeophilic cells. CONCLUSION: Using our own method of analyzing Papanicolaou-stained sputum, a new quantitative and qualitative analysis of stain color for standardized Papanicolaou stain was introduced.

Carcinoma, Squamous Cell↗
PubMed1998

Fluorescence derivatizing procedure for 5-hydroxytryptamine and 5-hydroxyindoleacetic acid using 1,2-diphenylethylenediamine reagent and their sensitive liquid chromatographic determination.

A pre-column derivatization method using a fluorogenic reagent, 1,2-diphenylethylenediamine (DPE) was studied for the sensitive HPLC determination of 5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA), which are biosubstances used in the diagnosis of several diseases. For the quantitative determination, the biogenic indole compounds were converted to their corresponding fluorescent derivatives with DPE in the presence of potassium hexacyanoferrate (III) at room temperature, and then the derivatives were separated by reversed-phase liquid chromatography with fluorescence detection. The chromatographic detection limits of the fluorescent peaks at a signal-to-noise ratio of 3 were 0.3 fmol for 5-HT and 0.2 fmol for 5-HIAA. The proposed method permits the simultaneous quantification of 5-HT and 5-HIAA at concentrations higher than 2.4 nM in human urine without a clean-up procedure.

Chromatography, High Pressure Liquid↗
PubMed1998

A compact UHV X-ray diffractometer for studying surfaces and interfaces.

A compact ultra-high-vacuum (UHV) X-ray diffractometer for surface glancing X-ray scattering has been constructed. All the equipment, including a rotating-anode source of 18 kW and a UHV specimen chamber, is arranged on one optical table of dimensions 70 x 90 cm. The specimen chamber is 14 cm in diameter and 20 cm high and can be evacuated up to 3 x 10(-8) Pa. It is equipped with two Be windows of thicknesses 0.2 and 0.4 mm. Specimen orientation in the vacuum is controlled from the outside. The specimen can be heated up to 773 K. The chamber has two evaporation cells and can be used for in situ observations of growing crystal surfaces. Using this instrument, we observed a mechanically polished Ag surface and successfully made an in situ observation of the layer-by-layer growth of a PbSe(111) surface. The instrument will be useful for preliminary experiments using laboratory sources, prior to final measurements at synchrotron radiation facilities.

Journal Article↗
PubMed1998

A new Drosophila ultraviolet light-damaged DNA recognition endonuclease that selectively nicks a (6-4) photoproduct site.

We have previously described the purification of an ultraviolet light (UV) damage-specific DNA-binding protein from Drosophila melanogaster, designated D-DDB P1 [Nucleic Acids Res., 23 (1995) 2600-2607]. Here, we obtained highly purified D-DDB P1 from Drosophila Kc cells, and we found that D-DDB P1 is also a nuclease. D-DDB P1 can selectively bind to pyrimidine (6-4) pyrimidone photoproducts, and in the presence of Mg++, D-DDB P1 can catalyze an incision immediately on the 3' and 5' sides of the (6-4) photoproduct site.

Animals↗
PubMed1998

Myocardial DNA strand breaks are detected in biopsy tissues from patients with dilated cardiomyopathy.

BACKGROUND: Progressive damage of cardiomyocytes with interstitial and replacement fibrosis accompanied by less inflammatory cell infiltration is observed in patients with dilated cardiomyopathy (DCM), suggesting some other mechanisms rather than necrotic cell death. HYPOTHESIS: The aim of this study was to assess the possible involvement of apoptotic process in the pathogenesis of DCM and myocarditis. METHODS: Endomyocardial biopsy was performed in patients with DCM (n = 9), myocarditis (n = 4), or atypical chest pain syndrome (as controls; n = 5). The TUNEL method was used for in situ detection of oligonucleosomal DNA strand breaks. RESULTS: The TUNEL-positive cells were observed in three of nine patients with DCM and in all four with myocarditis, but in none of the controls. The TUNEL-positive nuclei were observed exclusively in cardiomyocytes in DCM, whereas in myocarditis they were detected mainly in interstitial cells and in a few myocytes. In DCM, interstitial fibrosis was greater in the TUNEL-positive than in TUNEL-negative patients (p < 0.05). In either DCM or myocarditis, electron microscopic examination could not reveal morphologic features of apoptosis of cardiomyocytes. CONCLUSION: The DNA strand breaks were detected in cardiomyocytes in patients with DCM and mainly in interstitial cells in myocarditis. It is possible that the DNA strand breaks can be involved in mechanisms of progressive loss of functional cardiac units in these myocardial diseases.

Adult↗
PubMed1998

The possible role of interleukin (IL)-12 and interferon-gamma-inducing factor/IL-18 in protection against experimental Mycobacterium leprae infection in mice.

Cell-mediated immunity participates in host defense against mycobacterial infection. Both interleukin 12 (IL-12) and interferon-gamma-inducing factor (IGIF/IL-18), produced mainly by macrophages, play a critical role in expression of cell-mediated immunity. To investigate the role of IL-12 and IGIF/IL-18 in vivo, we examined cytokine profile, bacterial growth, and the potential benefit of cytokine therapy in susceptible and resistant mice infected with Mycobacterium leprae. The early expression of IL-12 p40 and IGIF/IL-18 at the site of inoculation was found in resistant mice 3-72 h after the infection, but not in susceptible mice. Both strains of mice did not show expression of IFN-gamma and IL-4. IL-12 administration resulted in a significant reduction of bacterial counts in mice with established M. leprae infection. The results imply that susceptible mice exhibit decreased expression of type 1 helper T (Th1) response without reciprocal increased Th2 response and show responsiveness to exogenous IL-12. IL-12 therapy may be a possible rationale for treatment of M. leprae infection.

Animals↗
PubMed1998

Monte Carlo simulation of DNA strand-break induction in supercoiled plasmid pBR322 DNA from indirect effects.

We present a new Monte Carlo simulation code system (DBREAK) of the detailed events that occur when ionizing radiation interacts with water and DNA molecules. The model treats the initial energy deposition by radiation, the formation of chemically active species, subsequent diffusion-controlled chemical reactions, and induction of DNA strand breaks. DBREAK assumes one-hit single-strand break (SSB) and two-hit double-strand break (DSB) mechanisms. A high-resolution model of plasmid DNA structure has been introduced. The calculated results are compared with the results of previously performed experiments of the same type. Under aerobic conditions, 89.4% of the DNA damage was attributed to OH-radical and 10.5% and 0.1% to eaq- and H, respectively. We also compared the differences between liquid-water track structure and gas-phase-water track structure. The calculated yield of SSBs by liquid-water track structure exceeded that of gas-phase-water track structure by a factor of 1.2.

Aerobiosis↗
PubMed1998

Genomic organization and mapping of the human activin receptor type IIB (hActR-IIB) gene.

Activins, members of a family of proteins that includes transforming growth factor-beta (TGF-beta), are gonadal polypeptide hormones that stimulate secretion of follicle-stimulating hormone (FSH). During large-scale sequencing analysis of a 1.2-Mb fragment of human genomic DNA on 3p22-p21.3, we found the gene encoding activin receptor type IIB (hActR-IIB). Comparison of its reported cDNA sequence with this genomic sequence showed that the hActR-IIB gene consists of 11 exons and spans about 30 kb of genomic DNA.

Activin Receptors, Type II↗
PubMed1998

Peripheral blood levels of matrix metalloproteases-2 and -9 are elevated in patients with acute coronary syndromes.

OBJECTIVES: This study was sought to investigate whether peripheral blood levels of matrix metalloproteases (MMPs) are affected in patients with acute coronary syndromes (ACS). BACKGROUND: Synthesis of MMPs has been reported in coronary atherosclerotic lesions in patients with unstable angina (UA), suggesting a pathogenic role of MMPs in the development of ACS. METHODS: Using sandwich enzyme immunoassay, serum MMP-2 and plasma MMP-9 were measured in 33 patients with ACS (22 with acute myocardial infarction [AMI], 11 with UA), 17 with stable effort angina (EA) and 17 normal control subjects. RESULTS: Serum MMP-2 in patients with UA and AMI on day 0 was two times greater than that in control subjects, and patients with EA showed higher MMP-2 levels than those in control subjects. Plasma MMP-9 in patients with UA and AMI on day 0 was elevated by threefold and twofold versus that in control subjects, respectively. In patients with UA and AMI who underwent medical treatment (n = 11 and 13, respectively), MMP-2 elevation was sustained until day 7. In patients with UA, MMP-9 elevation on day 0 was followed by a gradual decrease toward the control range up to day 7. Some patients with AMI showed a transient MMP-9 elevation with a peak on day 3, whereas in others, MMP-9 levels were significantly elevated on day 0 and remained higher than those in control subjects up to day 3. CONCLUSIONS: Serial changes in serum MMP-2 and plasma MMP-9 were documented in patients with ACS. These findings provide an insight into the molecular mechanism of plaque destabilization.

Angina Pectoris↗
PubMed1998

[Geographical distribution of Mycobacterium avium complex in environment and serovars of Mycobacterium avium complex isolates from patients with and without AIDS].

Mycobacterium avium complex (MAC) organisms have been isolated from water and soil. It is now generally accepted that environmental sources, especially natural waters, are the reservoirs for most human infections caused by MAC. Previously, we reported that M. avium and M. intracellular were distributed predominantly in the eastern and western part of Japan, respectively. To clarify the factor(s) of the difference, the following experiment was undertaken. MAC was isolated from soil samples collected in Tokai, Kinki and Chugoku districts, by the method of Ichiyama et al. MAC isolates were identified by AccuProbe Confirmation and Identification tests, together with some conventional tests. Seven (11.7%) of 60 isolates were identified as M. avium, twenty (33%) as M. intracellulaer and 33 (55%) as MAC-like organisms. Therefore, it was not found that the difference in the geographical distribution between soil MAC and disease-associated MAC. MAC-like strains possess MAC-specific alpha antigen, and biological and biochemical features of MAC. They reacted with the AccuProbe MAC but not with the AccuProbe M. avium and M. intracellulare. Sequencing analysis of 16s RNA gene implies that MAC-like strains show an intermediate sequence pattern of M. avium and M. intracellulare. HPLC patterns of these strains were compatible with those of MAC. It is known that the major serovars of MAC isolates from patients with or without AIDS are different. Serological aspects in this respect are not yet elucidated well in Japan. The major serovars of MAC from patients with AIDS are 4 and 8 in the USA and Australia, 6 and 4 in Sweden, and 8/21 and 8 in Germany. On the other hand, the major serovars of MAC from patients without AIDS are 8 and 16 (15) in the USA and 6 and 1 in Sweden. According to out recent study the major serovars of MAC from non-AIDS patients are 1 and 8 in the eastern part and 16 and 14 in the western part of Japan. In the present study, 38 MAC isolates from sputum, stool and blood and AIDS patients were identified. All of the isolates were identified as M. avium. Serovars of 15 strains were 4 (4 strains), 8 (3 strains), 9 (3 strains), 3 (2 strains), Darkin (2 strains) and 1 (1 strain). Therefore, it seems that the major serovars of the Japanese MAC strains from AIDS patients are similar to those of the American MAC strains from such patients.

Acquired Immunodeficiency Syndrome↗