Biomedical subjects

M Takasaki

Publications and source records attributed to M Takasaki.

At least 127 records · Page 7Linked to original sources

PubMed1998

A study of peripheral airway findings using an ultrathin bronchofiberscope and bronchoalveolar lavage fluid with diffuse panbronchiolitis.

We investigated the peripheral airways using an ultrathin bronchofiberscope and analyzed bronchoalveolar lavage fluid (BALF) in 10 patients with diffuse panbronchiolitis (DPB; refractory and responsive to treatment with macrolide antibiotics) and 10 healthy volunteers. Refractory DPB patients had obstruction at the 11th or 12th level of bronchial branches and secretion from the 5th to 6th order bronchi to the 11th-12th level of bronchial branches. In responsive DPB patients, there was no obstruction of peripheral airways, but secretion in the bronchial lumens still remained in nearly all observed bronchial branches. Despite macrolide therapy, BALF from patients with refractory DPB contained a high percentage of neutrophils and had a lower CD4/CD8 ratio. Two-color analysis of T cell subsets in BALF revealed a high percentage and number of CD8+S6F1+ cells (activated cytotoxic T cells) in refractory DPB patients. Our findings suggest that obstruction around the terminal bronchioles may be correlated with BALF abnormalities and may be irreversible despite macrolide therapy in progressive DPB.

Adult↗

PubMed1998

Anti-tumor-promoting activity of majonoside-R2 from Vietnamese ginseng, Panax vietnamensis Ha et Grushv. (I).

Seven saponins (1-7) isolated from the rhizomes and roots of Panax vietnamensis were tested for their inhibitory effects on Epstein-Barr virus early antigen (EBV-EA) induced by the tumor promoter, 12-O-tetradecanoylphorbol-13-acetate (TPA), in Raji cells as a primary screening test for anti-tumor-promoters (cancer chemopreventive agents). The ocotillol-type saponin, majonoside-R2 (2), which is the major and characteristic constituent of this plant, exhibited a significant inhibitory effect on EBV-EA activation. Furthermore, the cell cycle analysis of 2 on Raji cells was also examined and strong inhibition was observed on the effect of the cell cycle induced by TPA. Compound 2 showed potent anti-tumor-promoting activity in two-stage carcinogenesis tests of mouse skin using 7,12-dimethylbenz[a]anthracene (DMBA) as an initiator and TPA or fumonisin B1 as a promoter. Consequently, these results suggest that majonoside-R2 (2) could be a valuable chemopreventive agent against chemical carcinogenesis.

Animals↗

PubMed1998

Anti-tumor-promoting activity of diterpenes from Excoecaria agallocha.

To search for possible anti-tumor-promoters, we carried out the primary screening of seventeen diterpenes (1-17) isolated from the resinous wood of Excoecaria agallocha (Euphorbiaceae) using an in vitro synergistic assay system. Of these diterpenes, ent-16-hydroxy-3-oxo-13-epi-manoyloxide (5), (13R,14R)-ent-8alpha,13;14,15-diepoxy-13-epi- labda-3beta-ol (8) ent-3beta-hydroxy-15-beyeren-2-one (10) and ent-15-hydroxy-labda-8(17),13E-dien-3-one (14) exhibited significant inhibitory effects on Epstein-Barr virus (EBV) activation induced by the tumor promoter, 12-O-tetradecanoylphorbol-13-acetate (TPA). Furthermore, 10 exhibited remarkable anti-tumor-promoting activity in vivo on a two-stage carcinogenesis test of mouse tumor using 7,12-dimethylbenz[a]-anthracene (DMBA) as an initiator and TPA as a promoter.

9,10-Dimethyl-1,2-benzanthracene↗

PubMed1998

Dissociation of adrenomedullin concentrations in plasma and cerebrospinal fluid in pregnant and non-pregnant women.

Adrenomedullin (AM), a potent vasodilator peptide, has been shown to act within the central nervous system to modulate fluid and electrolyte balance. AM-immunoreactive cells have been found in the anterior pituitary gland and the choroid plexus of humans. In addition, AM activity has been implicated in the regulation of maternal circulation during pregnancy. To determine the relationship between AM concentration in the cerebrospinal fluid (CSF) and plasma, we measured AM levels in CSF and plasma of pregnant (group P, n = 12) and non-pregnant (group NP, n = 10) women scheduled to undergo gynecologic or obstetric surgery. In both groups, the concentration of AM in the plasma exceeded that in the CSF. Plasma AM concentration was significantly higher in pregnant than non-pregnant women (17.3+/-5.8 vs 5.1+/-1.4 pmol/l, mean +/- S.D.; P<0.01), whereas CSF AM concentration did not differ between the two groups (1.3+/-0.9 and 0.9+/-0.4 pmol/l in groups P and NP respectively). No significant correlation was found between AM concentrations in the CSF and plasma. The present findings suggest that AM is present in the CSF and that its concentration in the CSF is regulated independently from that in the plasma.

Adrenomedullin↗

PubMed1998

Diffusion-weighted magnetic resonance and magnetization transfer imaging in the assessment of ischemic human stroke.

We compared characteristic features in ischemic stroke lesions from the hyperacute to the chronic stage on diffusion-weighted (DW) and magnetization transfer (MT) images with those on T2-weighted (T2W) images, and assessed changes in apparent diffusion coefficient (ADC), MT effect (MTe), and T2 ratios (infarct/normal) over time. DW images were particularly useful for detecting hyperacute infarcts within 6 hours of onset and in distinguishing acute lesions from chronic lesions. ADC ratios were lower within 7 days after onset and rose toward 1.0 in the subacute phase, becoming relatively isotense on ADC maps, but elevated thereafter. Although MTe ratios were unchanged or only subtly changed in the acute stage, they became significantly lower in the subacute and chronic stages. These combined magnetic resonance (MR) techniques were useful in the assessment of ischemic stroke and facilitated the determination of the age of cerebral infarct.

Aged↗

PubMed1998

[Degenerative dementia of the oldest old].

We investigated seven brains from patients 99-105 years of age with a clinical diagnosis of Alzheimer-type dementia (ATD). The pathological findings were as follows. 1) These cases could be divided into two groups: cases with localized cortical atrophy in the medial part of the temporal lobe, and a case with diffuse atrophy in the cerebral cortex. Atrophied cortex in both groups showed laminar degeneration consisting of neuronal loss, neuropil loosening and astrocytosis resulting in fibrillary gliosis, which was particularly marked in the 2nd and 3rd layers of the cerebral cortex. In contrast, the structure of the six cortical layers was preserved when there was no laminar degeneration. Laminar degeneration correlated with cortical atrophy. 2) Cases with localized atrophy were further divided into two groups: group 1 (4 cases) showed small numbers of senile plaques (SPs) and large numbers of neurofibrillary tangles (NFTs' in CA1 of the hippocamupus, subiculum, and parahippohcampul gyrus, while group 2 (2 cases) showed widespread and numerous SPs and NFTs in the cerebral cortex. The distribution of SPs and NFTs in group 2 was similar to that of the case (group 3) with diffuse cortical atrophy. It was considered that group 2 was limbic type ATD and that group 3 was neocortical type ATD, because both groups met our pathological diagnostic criteria ATD. In contrast, group 1 could not be regarded as ATD because the numbers of SPs and NFTs were below those found in ATD, even though this group showed laminar degeneration the same as that of groups 2 and 3. It therefore is likely that group 1 is a unique type of degenerative dementia, pathogenetically different from ATD.

Aged↗

PubMed1998

[An elderly patient with an insulinoma who had prolonged dementia-like symptoms].

A 77-year-old woman had suffered from memory disturbance and disorientation for two years before she was admitted to the hospital because of confusion. Her score on the Hasegawa dementia scale revised (HDS-R) was 12 points at the time of the first medical examination. No other abnormalities could be found except for a blood glucose concentration of 34 mg/ dl. A Magnetic Resonance Image (MRI) of the brain showed some small lacunae on both sides in the frontal white matter and basal ganglia. After hospitalization, glucose was administered and the blood glucose concentration increased, but the dementia-like symptoms did not resolve. She was discharged because the symptoms were too difficult to control in the general hospital. Although dementia-like symptoms were present even after discharge, they did not necessarily appear during fasting. Six months later she was rehospitalized. The insulin-blood sugar ratio was at least 0.3 and abdominal echogram showed a 1-cm tumor at the tail of pancreas. The pancreas tail was removed and the tumor cells were reacted with anti-insulin-antibodies. One month after the operation, the dementia-like symptoms had resolved. The HDS-R score was improved to 27 points (normal range) 40 days after the operation. The amount of the slow waves in the electroencephalogram decreased 5 months after the operation. The dementia-like symptoms observed in this case could be regarded as the Durchgangssyndrom of Wieck. This syndrome is observed transiently at the time of recovery of deterioration of disturbances of consciousness. But it is treatable. This patient was an interesting case that showed Durchgangssyndrom mimiking dementia associated with insulinoma.

Aged↗

PubMed1998

[Cerebrovascular diseases in patients with arteriosclerotic aortic aneurysm and arteriosclerosis obliterans studied by carotid ultrasonography and by computed tomography of the brain].

To estimate the incidence of cerebrovascular diseases in arteriosclerotic aortic aneurysm (AA) and arteriosclerosis obliterans (ASO) and their characteristics, 92 patients with AA and 102 patients with ASO were studied with carotid ultrasonography and brain computed tomography (CT), and were compared with 49 patients with hypertension. The mean ages of the patients were 70 to 72 years old and all were male. Hypertension was common in the AA group: diabetes and cigarette smoking were common in the ASO group. Carotid plaque lesions seen on ultrasonography were significantly more common in the AA (66%) and ASO (85%) groups than in the patients with hypertension (39%). The mean carotid diameter was significantly greater in the AA group than in the other two groups. The mean wall thicknesses in the AA and ASO groups were greater than in the patients with hypertension. Computed tomography showed that low-density areas were also common in the AA group (56%) and ASO (53%) groups than in the patients with hypertension (24%). Most of the low-density areas were thought to be lacunae or dilated perivascular spaces in the subinsula and putamen. Moderately and highly severe periventricular lucencies were also common in the AA group. These findings indicate that carotid changes, seen in AA and ASO, reflected the characteristics of arterial lesions, and that arteriolosclerotic lesions were common in patients with AA and ASO. Therefore, cerebrovascular diseases should be taken into account in the management of patients with AA and ASO.

Aged↗

PubMed1998

[Atrophy and magnetization transfer ratio of the corpus callosum in patients with Alzheimer's disease].

We compared atrophy and magnetization transfer ratio (MTR) in the corpus callosum in patients with Alzheimer's disease and age-matched normal subjects. Fifteen patients with Alzheimer's disease and fourteen normal subjects received MRI. The corpus callosum was divided into three parts (anterior, middle, and posterior portions) on midsagittal slice, and their areas on T2-weighted reversed images and MTR on magnetization transfer contrast images in each portion were measured. The area and MTR decreased significantly in the posterior portion in patients with Alzheimer's disease. In the anterior portion, MTR decreased significantly, but although the area showed no significant change. In the middle portion, the area and MTR showed no significant change. MTR and the area was correlated in each portion in patients with Alzheimer's disease. The score of Hasegawa dementia scale-revised (HDS-R) and the area of the middle, posterior and total of corpus callosum were significantly related. The score of HDS-R and MTR in the anterior portion of corpus callosum were significantly related. The present study revealed decreases in MTR in the anterior portion of the corpus callosum of patients with Alzheimer's disease although the area showed no significant change, and this change suggests the increase in free water and/or the decrease in bound water in tissues, probably due to demyelination and axonal degeneration.

Aged↗

PubMed1998

[Propofol and sevoflurane--a comparison of anesthesia for laryngomicrosurgery].

Laryngomicrosurgery has some special characteristics. It is under much stress such as intubation and direct laryngoscopy during a short operation time. Therefore both adequate anesthesia and quick recovery are needed. Thirty three ASA physical status I patients for laryngomicrosurgery were randomly assigned to receive either anesthesia with propofol and small dose of fentanyl (Group P) or anesthesia with thiopental and sevoflurane (Group S). Group P was induced with propofol 2-3 mg.kg-1 and fentanyl 0.1 mg and maintained with propofol 6 mg.kg-1.h-1 (from 10 mg.kg-1.h-1 by 2 mg.kg-1.h-1 decrement in interval of 10 minutes). No intravenous analgesic was added. Group S was induced with thiopental 4 -5 mg.kg-1 and maintained with sevoflurane 2-3%. We compared emergence time and the state of recovery 5 minutes after extubation and 5 minutes after entering the recovery room. There was no episode of inadequate anesthetic state in both groups. The emergence time was significantly shorter in Group P than in Group S. The state of recovery was much better in Group P compared with Group S in both 5 minutes after extubation and 5 minutes after entering the recovery room. Therefore, anesthesia with propofol and small dose of fentanyl at induction is more adequate compared with anesthesia with sevoflurane in laryngomicrosurgery.

Adolescent↗

PubMed1998

[Anesthesia for a child with congenital sensory neuropathy with anhydrosis].

We gave anesthesia twice to a 4-year-old boy with congenital sensory neuropathy with anhydrosis. At the first surgery, anesthesia was induced with midazolam and maintained with nitrous oxide, oxygen and sevoflurane 0.5-0.8% under mask breathing. Surgery was performed without any trouble but the patient vomited postoperatively for three days. Next time, anesthesia was induced and maintained with propofol under mask. The patient often moved during surgery, and therefore, we changed from propofol to oxygen and sevoflurane 1.0-1.5% anesthesia. Nitrous oxide was not used. After the surgery, no vomiting occurred.

Anesthesia, Inhalation↗

PubMed1998

[The effects of flumazenil or bicuculline on the respiratory depression by morphine].

The effects of intravenous administration of flumazenil (n = 6) or bicuculline (n = 6) on the discharge of the phrenic nerve were studied following vagotomy in pentobarbital anesthetized mechanically ventilated rats. Morphine (0.4 mg.kg-1.min-1) was administrated until the respiratory rate decreased to about a half of the baseline respiratory rate. In this state, we first administered flumazenil (0.25 mg.kg-1) or bicuculline (0.4 mg.kg-1), intravenously and then administered naloxone (0.02 mg) intravenously in the two groups. The increase of inspiratory time from 0.7 +/- 0.1 to 2.0 +/- 0.5 s by morphine recovered to 0.8 +/- 0.2 s by bicuculline and to 0.6 +/- 0.1 s by naloxone. The increase of inspiratory time from 0.7 +/- 0.1 to 1.7 +/- 0.3 s by morphine, and to 2.1 +/- 0.5 s by flumazenil recovered to 0.6 +/- 0.1 s by naloxone. Expiratory time did not change during each drug administration in the two groups. The decrease of respiratory rate from 44 to 23 +/- 4 breaths.min-1 by morphine recovered to 37 +/- 5 breaths.min-1 by bicuculline and to 42 +/- 2 breaths.min-1 by naloxone. The decrease of respiratory rate from 45 +/- 3 to 22 +/- 6 breaths.min-1 by morphine, and to 18 +/- 4 breaths.min-1 by flumazenil recovered to 46 +/- 3 breaths.min-1 by naloxone. Amplitude of integrated phrenic nerve discharge increased to 125 +/- 42% by bicuculline and to 175 +/- 93% by naloxone compared to the baseline values. The decrease of amplitude to 54 +/- 18% by flumazenil recovered to 125 +/- 42% by naloxone. These results suggest that bicuculline not flumazenil antagonizes the respiratory depression of morphine by increasing the respiratory rate and respiratory movement.

Action Potentials↗

PubMed1998

[Low-dose CDDP and continuous 5-FU treatment of advanced gastric cancer with peritoneal dissemination: a case with long disease-free survival].

The patient was diagnosed to have gastric cancer (T3 N3 M0 P3, Stage IV b). We conducted LcFP therapy. CDDP, 7 mg/m2/day, day 1-5 i.v. drip for 2 hours, and 5-FU, 170 mg/m2/day, day 1-7, i.v. continuously for 24 hours. After 3 courses (one course: 4 LcFPs followed by one rest week), down staging (T3 N2 M0 P1. Stage IV a) and improvement of performance status were obtained, and then surgical resection was undertaken. After operation one course of LcFP therapy served as adjuvant chemotherapy. The patient has survived over one year and 8 months to date in a tumor-free condition. LcFP therapy promises to be useful in the clinical management of advanced gastric cancer.

Adenocarcinoma↗

PubMed1998

[Effect of epidural anesthesia on airway constriction induced with methacholine or capsaicin in cats].

The choice of epidural anesthesia for patients with bronchial asthma is controversial. We studied the effect of epidural anesthesia on airway constriction induced by methacholine or capsaicin in cats. Cats were anesthetized with pentobarbital and mechanically ventilated. Peak airway pressure and compliance, as well as cardiac sympathetic and vagal nerve activity were recorded. We sprayed 0.2% methacholine of 0.2% capsaicin into the trachea to produce airway constriction, and 15 min after drug spray we injected 2% lidocaine 1.0 ml into the epidural space. Methacholine increased peak airway pressure by 25% and decreased compliance by 26%. Capsaicin increased peak airway pressure 20% and decreased compliance 22%. After epidural anesthesia, cardiac sympathetic nerve activity decreased to 40% and 44%, vagal nerve activity decreased to 92% and 61% of control values in methacholine and capsaicin groups, respectively. However, here were no changes in the peak airway pressure and compliance in the two groups. These results suggest that epidural anesthesia, even if epidural anesthesia decrease sympathetic nerve activity, has no effect on the airway constriction induced with methacholine or capsaicin.

Action Potentials↗

PubMed1998

[Sedative and hypnotic properties of propofol during epidural or spinal anesthesia].

The sedative and hypnotic properties of propofol were studied in 40 patients undergoing elective gynecologic or orthopedic surgery using epidural (epidural group, n = 20) or spinal (spinal group, n = 20) anesthesia. Patients were given a bolus dose of 1 mg.kg-1 immediately followed by a continuous infusion of 4 mg.kg-1.h-1 of propofol after epidural or spinal anesthesia. The patients were asked to open their eyes on command at 10-sec interval from the end of the bolus infusion of propofol. We administered oxygen when SpO2 decreased below 93%. The mean induction time to reach the level of sedation, no response to verbal command to open their eyes, was 6 +/- 10 (SD) min in the epidural group, and 7 +/- 17 min in the spinal group. The mean recovery times, judged by ability to open eyes and recall date of birth, were 4 +/- 4 min and 7 +/- 6 min in the epidural group, and 4 +/- 4 min and 5 +/- 5 min in the spinal group, respectively. There were no differences in all recorded times between the two groups. Oxygen inhalation was needed in 75% of the patients in the epidural group and 100% in the spinal group. These results indicate that bolus and continuous infusion of propofol produces rapid induction, deep level of sedation, and rapid recovery during epidural or spinal anesthesia. However, respiratory depression appeared at this infusion rate during regional anesthesia.

Adjuvants, Anesthesia↗

PubMed1998

[Magnetization transfer imaging of periventricular white matter lesions in patients with multi-infarct dementia].

Using magnetization transfer (MT) imaging, we studied the underlying pathological conditions of periventricular hyperintense (PVH) white matter changes seen on T2-weighted MR images of patients with multi-infarct dementia. Twenty-two patients with multiple lacunar infarcts and PVH lesions, including 11 with dementia (diagnosed as multi-infarct dementia) and 11 without dementia, and 10 control subjects (with multiple lacunes, but no PVH lesion) were studied using the MT technique. MT ratios (MTRs) were calculated for PVH lesions (normal-appearing frontal white matter in controls) and the genu of the corpus callosum. Signal intensities on T2-weighted images in PVH lesions of patients were significantly higher than those in normal-appearing white matter of controls, while there were no significant differences in signal intensity in the genu of the corpus callosum among the dementia, non-dementia and control groups. However, MTRs in patients with PVH lesions were significantly lower than those in controls, and MTRs in demented patients were significantly lower than those in non-demented patients. Moreover, MTRs in the genu of the corpus callosum of demented patients were significantly lower than in those in non-demented patients and controls. MTRs in PVH lesions and the genu of the corpus callosum significantly correlated with Hasegawa's dementia scale score. These results suggest that there is some difference in histopathologic changes of PVH lesions between demented and non-demented patients and that the pathological substrate in the corpus callosum may play a role in inducing cognitive decline. Studies with MT imaging may allow the characterization of different pathological conditions that cannot be visualized by conventional MRI.

Aged↗

PubMed1997

Monocarboxylic acids enhance the anesthetic action of procaine by decreasing intracellular pH.

Sodium monocarboxylates are known to enhance the anesthetic action of procaine, and also decrease intracellular pH (pHi). We studied the effect of 30 mM Na monocarboxylates (formate, acetate, propionate, butyrate, and salicylate) on the pHi and on the anesthetic action of procaine HCl using giant axons of crayfish (Procambarus clarkii). The pHi was measured using pH sensitive microelectrode method and the anesthetic action was evaluated by the change in the action potential (AP) amplitude. The tested acids except for formate showed apparent decrease in pHi and enhancement of the action of 2 mM procaine. Other organic acids (maleate and benzensulfonate) did not affect pHi and anesthetic action of procaine. In the bicarbonate free solution, pHi increased and the anesthetic action was weakened. The EC25 values (the concentration of procaine which depresses the AP amplitude by 25%) of acetate, propionate, and bicarbonate free solution were coincided with the predicted EC25 values from the simple simulation on intracellular procaine increase according to the pHi change. But the EC25 value of salicylate group was less than half of the predicted. These results suggested that the enhancing action of straight chain monocarboxylic acids is due to pHi decrease, and salicylate has other additional mechanisms.

Action Potentials↗

PubMed1997

Anti-tumor promoting effects of naphthoquinone derivatives on short term Epstein-Barr early antigen activation assay and in mouse skin carcinogenesis.

In continuation of our studies of natural and synthetic products as cancer chemopreventive agents, we have examined a number of naphthoquinone derivatives including monomeric, dimeric and tetrameric naphthaquinones occurring in the Diospyros and other selected plant genera. Several synthetic naphthoquinones were also evaluated. Initially these compounds were tested for in vitro anti-tumor promoting effect on Epstein-Barr virus early antigen activation produced by the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) and thereafter in in vivo on two-stage mouse skin carcinogenesis. Our studies show some of these compounds have potent anti-tumor promoting activity.

Animals↗