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Biomedical subjects

M Takasaki

Publications and source records attributed to M Takasaki.

At least 73 records · Page 4Linked to original sources
PubMed2000

[A comparison of bullard laryngoscope and intubating laryngeal mask using fiberoptic guidance for tracheal intubation].

The purpose of this study is to compare the success rate of tracheal intubation, intubation time and laryngoscopic view of the larynx by Bullard laryngoscope or by intubating laryngeal mask using fiberoptic guidance in 50 patients. Following a standardized induction protocol, conventional laryngoscopic view by Macintosh's laryngoscope was obtained and classified by Cormack's grades. We measured the times from incertion of laryngoscopy or laryngeal mask until obtaining the best view of the larynx and until tracheal intubation. A best view by Bullard laryngoscopy or by fiberoscopy through the laryngeal mask was classified by Cormack's grades. The success rate of tracheal intubation was higher by Bullard laryngoscopy than by intubating laryngeal mask. The durations of laryngoscopy and tracheal intubation were significantly shorter and Cormack's grades were significantly lower by Bullard laryngoscopy than by laryngeal mask and fiberscopy. These results demonstrate that tracheal intubation by Bullard laryngoscope is faster and more successful compared with intubating laryngeal mask using fiberoptic guidance.

Adolescent↗
PubMed2000

Magnetization transfer measurements of the hippocampus in patients with Alzheimer's disease, vascular dementia, and other types of dementia.

BACKGROUND AND PURPOSE: Although atrophy of structures in the medial temporal lobe has been considered an indication of Alzheimer's disease (AD), atrophic changes on MR images have also been associated with other dementing diseases and are not specific to AD. This study was undertaken to determine whether characteristic alterations in the hippocampus of patients with AD are detectable with magnetization transfer (MT) imaging. METHODS: Coronal MT imaging was performed in 35 patients with probable AD, in 14 patients with vascular dementia, in 13 patients with other types of dementia, and in 23 control subjects to measure MT ratios of the hippocampus. Medial temporal lobe atrophy was graded subjectively on a five-point scale. RESULTS: Scores of medial temporal lobe atrophy in all dementia groups were significantly higher than those in control subjects, but no differences were found among the dementia groups. MT ratios in the hippocampus were significantly lower in patients with AD than in those with non-AD dementia and in the control subjects; however, no differences were found between the non-AD dementia patients and the control subjects. MT ratio measurements were better than visual analysis of atrophy for differentiating AD patients from those with non-AD dementia (an overall discrimination rate of 77% versus 65%). MT ratios significantly correlated with scores on the Mini-Mental State Examination and with medial temporal lobe atrophy in AD patients but not in patients with non-AD dementia. CONCLUSION: MT measurements may be more specific than visual analysis in detecting structural damage of the hippocampus in AD patients and might be useful in discriminating AD from vascular dementia and other types of dementia.

Aged↗
PubMed2000

[Comparison of epidural anesthesia and general anesthesia for patients with bronchial asthma].

We prospectively investigated the incidence of asthmatic attacks in 94 patients (1.5%) who were diagnosed as definite asthma. We separated the patients into three groups: epidural anesthesia (n = 10) including combined spinal/epidural anesthesia (n = 7), combined epidural and general anesthesia (n = 23), and general anesthesia (n = 54). General anesthesia was induced with propofol or midazolam and maintained with N2O and O2 with sevoflurane in adults. Patients who underwent epidural anesthesia and combined spinal and epidural anesthesia showed no asthmatic attacks. The incidence of bronchospasm with combined epidural and general anesthesia was 2/23. The incidence of bronchospasm with general anesthesia was 4/54. Bronchoconstriction occurred after tracheal intubation in 5 patients except in one patient, in whom it occurred after induction of anesthesia with midazolam. All episodes of bronchospasm in the operative period were treated successfully. The frequency of bronchospasm did not depend on the severity of asthmatic symptoms or the chronic use of bronchodilators before operation. These findings suggest that tracheal intubation, not the choice of anesthetic, plays an important role in the pathogenesis of bronchospasm.

Adult↗
PubMed2000

Multi-effective properties of homogentisic acid revealed in reactions with human hemoglobin and human erythrocytic hemoglobin.

Homogentisic acid (HGA) causes oxidation of human oxyhemoglobin and reduction of methemoglobin. The rate of oxidation of oxyhemoglobin by HGA is greatly accelerated in the presence of myo-inositol hexakis-phosphate (P6-inositol) or superoxide dismutase (SOD), but is inhibited in the presence of catalase. The reduction rate of methemoglobin by HGA is accelerated in the presence of P6-inositol but is greatly inhibited in the presence of SOD. It is suggested that the semiquinone and quinone form of HGA and oxygen radicals may be involved in the mechanism of oxido-reductive reactions of human hemoglobin with HGA. In addition, a new anodic hemoglobin found by isoelectric focusing electrophoresis was produced during the reaction of oxyhemoglobin with HGA. When human erythrocytes were exposed to HGA for several hours at 37 degrees C (pH 7.4), the anodic oxyhemoglobin (HGA-modified hemoglobin) and its half met-form hemoglobin [(alpha3+beta2+)2 of HGA-modified hemoglobin] were produced in significant amounts. HGA-modified hemoglobin was stably purified and showed increased oxygen affinity, absence of titratable sulfhydryl groups, and the absorption spectrum of normal oxyhemoglobin. Our results demonstrate that HGA shows multiple effects on human hemoglobin and erythrocytic hemoglobin, which is consistent with the evidence that HGA is involved in various pathological conditions such as arthritis and carcinogenesis in humans.

Erythrocytes↗
PubMed2000

[Analysis of inadvertent epidural injection of drugs].

We asked 31 anesthesiologists, who were on the Japanese Board of Anesthesiology, about inadvertent injection of drugs into the epidural space, and received answers from 28 (90%). Fifteen (54%) had an experience of inadvertent epidural injection, and five of them had two experiences. Injected drugs were ephedrine (6 times), a mixture of neostigmine and atropine (3), thiopental (2), etilefrine (2), vecuronium (1), suxamethonium (1), bicarbonate (1), midazolam (1), lactated Ringer's solution (1), nicardipine (1), and pentazocine (1). The inadvertent injection of thiopental or bicarbonate was noticed by back pain during injection. No treatment was added after the inadvertent injections, except a patient with an epidural steroid injection following thiopental. No neurological complications were found in any patients.

Anesthesia, Epidural↗
PubMed1999

Cancer chemopreventive activity of majonoside-R2 from Vietnamese ginseng, Panax vietnamensis.

In the course of our continuing search for novel cancer chemopreventive agents from natural sources, several kinds of Panax plants were screened. Consequently, the ocotillol-type saponin, majonoside-R2 (MR2), was obtained from the rhizome and root of Panax vietnamensis (Vietnamese ginseng) as an active constituent. MR2 exhibited potent anti-tumor-promoting activity on two-stage carcinogenesis test of mouse hepatic tumor using N-nitrosodiethylamine (DEN) as an initiator and phenobarbital (PB) as a promoter. Further, MR2 exhibited the remarkable inhibitory effect on two-stage carcinogenesis test of mouse skin induced by nitric oxide (NO) donor/12-O-tetradecanoylphorbol-13-acetate (TPA) or peroxynitrite/TPA.

Alkylating Agents↗
PubMed1999

Excitatory synaptogenesis between identified Lymnaea neurons requires extrinsic trophic factors and is mediated by receptor tyrosine kinases.

Neurotrophic factors have well established roles in neuronal development and adult synaptic plasticity, but their precise role in synapse formation has yet to be determined. This paper provides the first direct evidence that neurotrophic factors in brain conditioned medium (CM) differentially regulate excitatory and inhibitory synapse formation. Somata of identified presynaptic and postsynaptic neurons were isolated from the CNS of Lymnaea and were cultured in a soma-soma configuration in the presence (CM) or absence [defined medium (DM)] of trophic factors. In DM, excitatory synapses did not form. When they were paired in CM or in DM containing Lymnaea epidermal growth factor (EGF); however, all presynaptic neurons reestablished their specific excitatory synapses, which had electrical properties similar to those seen in vivo. CM-induced formation of excitatory synapses required transcription and de novo protein synthesis, as indicated by the observations that synapse formation was blocked by the protein synthesis inhibitor anisomycin and the protein transcription blocker actinomycin D; the CM factor was inactivated by boiling. They were also blocked by receptor tyrosine kinase inhibitors (lavendustin A, genistein, K252a, and KT5926) but not by inactive analogs (genistin and lavendustin B), suggesting that the effect was mediated by receptor tyrosine kinases. These results, together with our previously published data, demonstrate that trophic factors are required for excitatory, but not inhibitory, synapse formation and extends the role of EGF from cell proliferation, neurite outgrowth, and survival to excitatory synapse formation.

Action Potentials↗
PubMed1999

Anti-tumor promoting activity of polyphenols from Cowania mexicana and Coleogyne ramosissima.

Chemical investigation on polyphenol-rich fractions of Cowania mexicana and Coleogyne ramosissima (Rosaceae) which showed significant inhibitory effects on Epstein-Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol-13-acetate (TPA), has led to the characterization of 10 compounds including C-glucosidic ellagitannin monomers and dimers from the former plant, and 17 polyphenols including flavonoid glycosides from the latter. The effects of individual components and their analogues with related structures on the TPA-induced EBV-EA activation were then evaluated. Among the compounds isolated from C. mexicana, two C-glucosidic ellagitannins, alienanin B and stenophyllanin A and a nitrile glucoside (lithospermoside), and among the constituents from C. ramosissima, two flavonoid glycosides, isorhamnetin 3-0-beta-D-glucoside and narcissin were revealed to possess strong inhibitory effects on EVB-EA activation, the potencies of which were either comparable to or stronger than that of a green tea polyphenol, (-)-epigallocatechin gallate. These polyphenols except for nitrile glucoside, which was not tested owing to an insufficient amount, were also found to exhibit anti-tumor promoting activity in two-stage mouse skin carcinogenesis using 7,12-dimethylbenz[a]anthracene (DMBA) and TPA.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1999

Diffusion-weighted and magnetization transfer imaging of the corpus callosum in Alzheimer's disease.

We investigated structural changes of the corpus callosum in patients with Alzheimer's disease (AD) using sagittal diffusion-weighted (DW) and magnetization transfer (MT) imaging. Patients with AD (n=23) had a significantly decreased area only in the posterior portion of the corpus callosum. Apparent diffusion coefficient (ADC) values perpendicular to the commisural fiber orientation were significantly higher in the anterior portion of the corpus callosum without definite atrophy, as well as in the posterior portion with significant atrophy, in patients with AD than in controls (n=16) and thus diffusion in these regions showed a significantly lower degree of anisotropy in patients than in controls. MT ratios were also significantly lower in patients with AD in the anterior and posterior portions of the corpus callosum than in controls. These findings probably reflect structural changes in the corpus callosum including axonal loss and/or demyelination. DW and MT imagings may be useful in detecting degeneration of the corpus callosum in AD.

Aged↗
PubMed1999

Magnetization transfer ratio in cerebral white matter lesions of Binswanger's disease.

We measured the magnetization transfer (MT) ratios in white matter lesions of Binswanger's disease (BD) and compared them with BD and with similar-appearing changes in non-demented elderly subjects and cerebral infarction. Four subject groups were studied: 30 patients with BD and periventricular hyperintensity (PVH) on MRI, 29 patients with ischemic cerebrovascular event with PVH but no dementia, 17 patients with old cerebral infarction, and 26 elderly control subjects. MT ratios were calculated for areas of PVH in BD and non-demented subjects, of infarction, and of normal-appearing white matter in controls. The decrease in MT ratios for areas in PVH of non-demented subjects and BD and in infarction compared with normal white matter in controls was 12, 20, and 35%, respectively. The MT ratio in PVH of BD was significantly lower than that in PVH of non-demented subjects, but not to the levels seen in areas of infarction. There was a significant high correlation between the Mini-Mental State Examination score and MT ratio for area of PVH (r = 0.790). MT ratio distinguishes PVH in BD patients from those in non-demented subjects, suggesting underlying histopathological differences. Tissue damage in white matter lesions of BD may be more severe than that in non-demented subjects, but not as much as with complete infarction.

Aged↗
PubMed1999

Cancer chemopreventive agents (antitumor-promoters) from Ajuga decumbens.

Sixteen compounds (1-16) isolated from the flowering whole plant of Ajuga decumbens have been tested for their inhibitory effects on Epstein-Barr virus early antigen (EBV-EA) induction by the tumor promoter, 12-O-tetradecanoylphorbol-13-acetate (TPA), as a primary screening test for antitumor-promoters (potential cancer chemopreventive agents). Five compounds (6, 9, and 12-14) showed strong inhibitory effects on EBV-EA induction. Of these active compounds, two major constituents of this plant, cyasterone (6) and 8-acetylharpagide (13), showed potent antitumor-promoting activities on a mouse-skin in vivo two-stage carcinogenesis procedure, using 7, 12-dimethylbenz[a]anthracene as initiator and TPA as promoter. Further, compound 13 also exhibited potent chemopreventive activity in a mouse pulmonary tumor model.

4-Nitroquinoline-1-oxide↗
PubMed1999

Dietary heme iron does not prevent postgastrectomy anemia but fructooligosaccharides improve bioavailability of heme iron in rats.

Gastrectomized rats exhibit iron deficiency anemia. We observed the effects of dietary heme-iron and short chain frucooligosaccharides (Sc-FOS) in relation to prevention of postgastrectomy anemia in rats. Twelve laparotomized (sham-operated) rats were fed iron-citrate (control) as iron source diet without or with Sc-FOS (75 g/kg of diet) and twenty four totally gastrectomized (Bilroth II) rats, were fed a iron-citrate (control) or heme-iron (heme) as iron source diet without or with Sc-FOS (75 g/kg of diet) for 4 weeks. All rats received an intramuscular injection of vitamin B-12 every two weeks. Tail blood was collected every other week for determination of hematocrit and hemoglobin concentration. At the end of the experiment, the rats were killed and whole blood was collected. The total gastrectomy induced the postgastrectomy anemia. Dietary Sc-FOS increase iron absorption and thereby prevented completely this anemia in gastrectomized rats fed the control diet but this effect of Sc-FOS in rats fed heme diet was not complete. Dietary heme iron could not prevent postgastrectomy anemia itself, but fructooligosaccharides improve bioavailability of not only non-heme iron such as iron-citrate, but also heme-iron in rats.

Anemia↗
PubMed1999

Aeromonas sobria infection with severe soft tissue damage and segmental necrotizing gastroenteritis in a patient with alcoholic liver cirrhosis.

A 49-year-old man, who had a 3-year history of liver dysfunction but had not been treated, was admitted to the hospital with a sudden onset of fever and generalized muscle pain. He subsequently developed generalized purpura with scattered hemorrhagic bullae of the skin and massive bloody stools. Aeromonas sobria was proven by culture of both blood and bullous fluid. In spite of the extensive treatment with antibiotics and other medications in the intensive care unit (ICU), the patient went into septic shock and died 2 days after admission. Pathological examination on autopsy revealed segmental necrotizing gastroenteritis with bacterial colonies and alcoholic liver cirrhosis, in addition to extensive severe soft tissue damage involving cellulitis and rhabdomyolysis and epidermolysis. Although the prognosis for Vibrio vulnificus infection with severe soft tissue damage in patients with liver cirrhosis, malignancy, diabetes mellitus or other pre-existing diseases is poor, the unfavorable progression of Aeromonas species, especially A. sobria infection is rare. This is thought to be the first report of an autopsied case.

Aeromonas↗
PubMed1999

Age-related changes in alpha-tocopherol dynamics with relation to lipid hydroperoxide content and fluidity of rat erythrocyte membrane.

Age-related changes in alpha-tocopherol dynamics in plasma and erythrocyte membranes of 10- to 120-week-old rats were investigated by high-performance liquid chromatography (HPLC) with redox detection mode. Furthermore, changes in lipid hydroperoxide content and fluidity of erythrocyte membrane with age were assessed using chemiluminescence-HPLC and Fourier transform infrared spectrophotometer, respectively. A slight increase in the alpha-tocopherolquinone/alpha-tocopherol ratio in erythrocyte membrane and a decrease in the alpha-tocopherol in erythrocyte membrane/alpha-tocopherol in plasma ratio were observed. A significant increase in lipid hydroperoxide content and a marked decrease in the fluidity of erythrocyte membrane were seen with age. These findings suggest that alpha-tocopherol uptake in erythrocyte membrane declines, and utilization rate of alpha-tocopherol in erythrocyte membrane increases age-dependently. These changes, which enhanced lipid peroxidation and consequently reduced membrane fluidity, may be caused by the impairment of this transfer mechanism.

Aging↗
PubMed1999

Regional differences in diffusion abnormality in cerebral white matter lesions in patients with vascular dementia of the Binswanger type and Alzheimer's disease.

We investigated changes in water diffusion in the cerebral white matter of 14 patients with vascular dementia of the Binswanger type (VDBT) and ten patients with Alzheimer's disease (AD) with periventricular hyperintensity (PVH) lesions using diffusion-weighted magnetic resonance imaging (MRI) and studied the pathophysiological differences between white matter lesions found in these two conditions. Apparent diffusion coefficients (ADCs) in the anterior and posterior white matter and the genu and splenium of the corpus callosum were significantly higher in both groups of patients than in the 12 age-matched controls, and ADC values in VDBT and AD groups were almost the same. ADC ratios, defined as diffusion restricted perpendicular to the direction of nerve fibers, were also significantly higher in the patients than in the control subjects. However, there were regional differences in ADC ratios in the two conditions, with ratios in VDBT being higher in the anterior portions of the white matter but ratios in AD were higher in the posterior portions. The diffusion-weighted MRI technique may be useful in the differential diagnosis of VDBT and AD with white matter lesions.

Aged↗