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Biomedical subjects

K Takada

Publications and source records attributed to K Takada.

At least 361 records · Page 20Linked to original sources
PubMed1995

[Effect of fluvoxamine, a new antidepressant drug, on monoamine dynamics in the rat cerebral limbic system and its pharmacological characteristic].

The effect of fluvoxamine (FLU) on the amine dynamics in serotonergic, noradrenergic or dopaminergic nervous systems in the rat cerebral limbic system was investigated, with reference to the pharmacological characteristics of FLU. Following single oral administration of 30 and/or 60 mg/kg FLU, significant decreases in the 5-hydroxyindole-3-acetic acid (5-HIAA)/serotonin (5-HT) ratios in the amygdala and hippocampus and the 4-hydroxy-3-methoxyphenylglycol (MHPG)/norepinephrine (NE) ratio in the amygdala were produced. FLU at 15 mg/kg, p.o. also caused a significant increase in MHPG/NE ratio in the hippocampus. On the other hand, imipramine (IMI) at 30 mg/kg, p.o. induced significant decreases in 5-HIAA/5-HT ratio in the hippocampus, MHPG/NE ratios in the amygdala and hippocampus, and 3,4-dihydroxyphenylacetic acid (DOPAC)/dopamine (DA) ratios in the amygdala, hippocampus and septum. The 5-HIAA/5-HT ratios in the amygdala and hippocampus and the MHPG/NE ratio in the septum were significantly decreased after repeated oral administration of 30 mg/kg FLU twice daily for 14 days, but the MHPG/NE ratio in the amygdala was increased. In the septum, DOPAC/DA ratio was significantly decreased following repeated administration of IMI at 30 mg/kg, p.o. These findings suggest that FLU inhibits 5-HT turnover in the amygdala and hippocampus as a result of the interference with the neuronal re-uptake mechanism for 5-HT. Also, FLU has an effect on NE turnover in the cerebral limbic system, and the effect may appear in connection with a change in the interaction of nervous systems.

Administration, Oral↗
PubMed1995

QT dispersion in acute myocardial infarction with special reference to left ventriculographic findings.

QT and QT dispersion, which is the time difference between QT maximum and QT minimum, were evaluated in 22 patients with anterior myocardial infarction approximately one month after onset. The purpose of this study was to observe how LV wall motion abnormally is related to these variables. Twenty age-matched patients without overt heart disease were also studied as a control group. QT and QT max in patients with acute myocardial infarction (AMI) were markedly prolonged compared to those in normal controls (472.8 +/- 48.0, 483.2 +/- 32.1 vs 390.2 +/- 18.8, and 418.0 +/- 21.0 msec, respectively). QT dispersion and QTc dispersion in patients with AMI were significantly more prolonged than in normal controls (111.2 +/- 33.9, (113.4 +/- 32.9 vs 54.3 +/- 15.0, and 60.3 +/- 17.2 msec, respectively). QT dispersion has a positive correlation with QT max in AMI patients. Ejection fraction (EF) of the left ventricle was relatively well maintained in cases where only one segment of the left anterior ventricular wall was impaired in its motion. It decreased, however, in accordance with the extent of wall motion abnormality QT max and QTc max were prolonged as the number of LV wall segments with impairment increased. This, however, was not statistically significant. QT dispersion and QTc dispersion had no relation to the extent of LV wall motion abnormality nor to EF of the left ventricle In conclusion, no definite relationships between QT dispersion (QTc dispersion) and EF of the left ventricle, or between these variables and the extent of left ventricular wall motion abnormality were found in patients with anterior myocardial infarction in our study. Although both QT max and QT dispersion were prolonged in patients with myocardial infarction, this suggests that electrical heterogeneity or regional variation in electrical ventricular recovery did not always parallel the severity of mechanical abnormality of the left ventricle.

Aged↗
PubMed1995

Molecular weight-dependent lymphatic transfer of fluorescein isothiocyanate-labeled dextrans after intrapulmonary administration and effects of various absorption enhancers on the lymphatic transfer of drugs in rats.

We have developed a new method to evaluate the transfer of macromolecular drugs to intrapulmonary lymph nodes in rats after intrapulmonary administration. By using this method, we observed that the transfer of fluorescein isothiocyanate dextrans (FDs) to the intrapulmonary lymph nodes was markedly higher than that to iliac lymph node, a non-intrapulmonary lymph node. The transfer of FDs to the intrapulmonary lymph nodes increased with increasing their molecular weights and the threshold for a high lymph node-to-plasma level ratio (CLN/CP) was between 10 and 20 kDa. The effects of absorption enhancers on the transfer of FDs to intrapulmonary lymph nodes were also examined in rats. Absorption enhancers used in this study were EDTA, sodium glycocholate (Na-GC), mixed micelles (MM), N-lauryl-beta-D-maltopyranoside (LM), sodium caprate (Na-Cap). The transfer of FD-20, FD-40 and FD-70 to intrapulmonary lymph nodes after intrapulmonary administration increased in the presence of LM. In particular, the lymphatic transfer of FD-40 was remarkably increased in the presence of LM. Similarly, Na-GC and MM improved the transfer of FD-40 to intrapulmonary lymph nodes. These results suggest that absorption enhancers such as LM, Na-GC and MM are effective for improving the transfer of macromolecular drugs to intrapulmonary lymph nodes.

Absorption↗
PubMed1995

Preparation and evaluation of a time-controlled release capsule made of ethylcellulose for colon delivery of drugs.

A novel ethylcellulose (EC) capsule which releases drug with a time-controlled fashion has been prepared. This capsule is composed of four parts, drug container, swellable substance, capsule body and cap. At the bottom of the body, micropores are made. As water penetrates through these micropores, the swellable substance such as low substituted hydroxypropyl cellulose (L-HPC) swells. When the cap made of water-insoluble macromolecular substance such as EC cannot persist the swelling pressure, the EC cap disintegrates and the drug in the container is released from the capsule. The lag-time is utilized for the delivery of drug to the colon. The release time of the drug from the capsule was measured both in vitro and in vivo experiments. In the case of an in vitro experiment, after 12mg of fluorescein as a model drug and 238mg of starch were filled into the container, caps having different thickness were attached to the capsule body and release study was performed. The release time of the drug was mainly dependent on the thickness of the cap. Using test capsules of which mean cap thickness were 39.1 +/- 2.3 (SE)microns, 63.1 +/- 5.0 microns and 75.6 +/- 4.1 microns, the in vivo release time was estimated after administration to beagle dogs. As a parameter, the peak time (tmax) when plasma fluorescein concentration reached to its maximum level was determined for the estimation of the release time of the drug from the capsule in the gastrointestinal tract. The in vivo tmax was well correlated with the cap thickness.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

The effects of oligomers content and surface morphology on foreign-body tumorigenesis with polyetherurethanes: two years subcutaneous implantation study in rats.

Three polyurethane materials were prepared by removing and adding the leachable oligomers from and to the same polyetherurethane (PEU). The three PEU materials were dissolved in tetrahydrofuran (THF) and dimethyformamide (DMF) and the solutions were cast on a glass plate to make films of smooth and foamed surfaces, respectively. These six materials and polydimethylsioxane (silicone) were implanted into subcutaneous pocket of rats for 2 years to evaluate the long-term effects around the implant. Among the smooth surface implants, PEU materials induced a higher incidence of tissue responses, including tumor formation than silicone. However, no relationship between the oligomer content and the tissue responses was found. Changing surface morphology from a smooth to a foamed one prolonged the latent period of tumor development and decreased the total tumor incidence.

Analysis of Variance↗
PubMed1995

[Long-term hemodialysis treatment using femoral vein puncture method (FV-method) as blood access in 12 patients].

It is well known that blood access is essential for long-term hemodialysis treatment. Arteriovenouos fistula (AVF) is the most widely used method. However, this method of access frequently fails (access failure) as a result of stenosis. We attempt simple femoral vein puncture (FV-method) instead of AVF in such patients and have experienced 12 patients who were undergoing hemodialysis treatment using the FV-method, three times a week for more than one year. We devised special needles (18- and 19-gauge) for the FV-method. Generally, we use a 19-gauge needle with 4 side holes. We discuss here the results of 12 patients consisting of 4 males and 8 females with a mean age of 57.9 years, a mean duration of dialysis of 10.0 years, and a mean duration of FV-method of 3.5 years. Their underlying diseases were chronic glomerulonephritis (9 patients), diabetic nephropathy (2 patients) and nephrosclerosis (1 patient). Before the use of the FV-method, AVFs were attempted a man of 3.8 times and an artificial graft, 4 times in 3 patients. Ten patients were outpatients and 2 were inpatients. As for the indications of the FV-method, 11 patients had access failure and another had suffered from heart failure resulting from an over flow of blood through AVF. KT/V, PCR and TACBUN were measured monthly and were within the normal range in almost all of the patients. Concerning complications of the FV-method, hematoma formation after detachment of the needle at the end of dialysis and pain at needle puncture were sometimes noted.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1995

[Serum levels of soluble receptors for tumor necrosis factor in sarcoidosis].

Tumor necrosis factor alpha (TNF-alpha) has been shown to play an important role in granulomatous diseases, including sarcoidosis. TNF-alpha starts affecting cell function by binding to specific, high-affinity receptors on the cell surface, and two types of TNF-alpha receptors have been identified. Recently, soluble forms derived these cell surface receptors (sTNF-R type I and type II) have been shown to exist and have been investigated in several diseases. The levels of sTNF-R type I and type II in serum from patients with sarcoidosis were measured, and the clinical significance of sTNF-R was evaluated. The levels of both sTNF-R type I and type II were significantly higher in serum from patients with sarcoidosis (n = 36) than in serum from control subjects (n = 15): type I, 1.93 +/- 1.28 ng/ml vs 1.31 +/- 0.40 ng/ml, p < 0.01; type II, 3.48 +/- 2.60 ng/ml vs 1.56 +/- 0.35 ng/ml, p < 0.001. The levels of these receptors were significantly higher in patients with active sarcoidosis than in those with inactive sarcoidosis: type I, 2.43 +/- 1.83 ng/ml vs 1.57 +/- 0.45 ng/ml, p < 0.05; type 4.71 +/- 2.24 ng/ml vs 2.25 +/- 0.77 ng/ml, p < 0.01. The levels of sTNF-R type I and type II correlated significantly with the level of ACE, r = 0.70, p < 0.01; and r = 0.55, p < 0.05, respectively. We conclude that measurement of the levels of both types of sTNF-R may be useful in the evaluation of disease activity in sarcoidosis.

Adolescent↗
PubMed1995

Role of transforming growth factor-beta 1 on platelet-induced enhancement of endothelin-1 production in cultured vascular endothelial cells.

We and other investigators obtained evidence that platelets stimulate endothelin-1 (ET-1) production at both message and protein levels in vascular endothelial cells (ECs), and that platelet-derived transforming growth factor-beta 1 (TGF-beta 1) is responsible for this stimulation. In the present study, we examined the effects of acidification or heat treatment, known to activate latent TGF-beta 1, on the platelet supernatant-induced ET-1 production in cultured porcine aortic ECs. Supernatant of platelets (6.0 x 10(8) platelets/ml) aggregated by adenosine diphosphate contained large amounts of TGF-beta 1, but were almost in a latent form, and the proportion of active TGF-beta 1 in the supernatant was increased markedly in the case of acidification or heat treatment. These treatments also significantly potentiated the supernatant-induced stimulation of prepro ET-1 mRNA expression and the ET-1 release in ECs. Purified TGF-beta 1 also enhanced ET-1 release, dose-dependently, but the enhancement declined at the higher concentrations. Thus, powerful stimulation of ET-1 production by platelet supernatant after acidification or heat treatment cannot be explained only by increments in active TGF-beta 1. The supernatant-induced stimulation of ET-1 synthesis was significantly inhibited by concomitant treatment of TGF-beta 1 neutralizing antibody, but this inhibition was incomplete even at a concentration that abolished TGF-beta 1-induced maximal stimulation. These results suggest that platelet-induced stimulation and subsequent acidification and heat treatment-induced potentiation on endothelial ET-1 production depend closely on release and activation of TGF-beta 1 derived from platelets.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Adult left isomerism complicated with life threatening arrhythmias detected by the use of biplane transesophageal echocardiography: a case report.

Left isomerism with critical arrhythmia in a 34-year-old housewife is reported. Left isomerism is rare among adult congenital disorders. The prognosis in childhood depends on intractable heart failure, but is unclear in adulthood. We describe an adult patient with left isomerism who recovered from life-threatening arrhythmias. Transesophageal echocardiography was especially useful to identify the morphology of both atrial appendages.

Adult↗
PubMed1995

Fatal Epstein-Barr virus-associated lymphoproliferative disorder in childhood.

OBJECTIVE: We report five childhood cases of fatal Epstein-Barr virus-associated lymphoproliferative disorder to determine their immunopathologic and immunogenotypic features. DESIGN: Clinicopathologic features are described, using clinical, histologic, immunophenotypic, and genotypic examinations. SETTING: Autopsy cases were performed at Nagoya and Tsukuba university hospitals, Japan. RESULTS: Infiltrating lymphocytes, which were positive for the EBV genome by in situ hybridization, were polymorphic and showed polyclonal immunoglobulin staining in all five cases. Two cases, however, showed genetic clonality of EBV termini. In one case, the clonality was observed only in the spleen, and in the other case, clonal rearrangement of the JH gene was also found. The former case showed none of the morphologic features of neoplasia and presented a morphology similar to virus-associated hemophagocytic syndrome. In the latter case, infiltrating lymphoid cells were much less polymorphous, and nodular masses of the lymphoid cells in colon and lung specimens were observed. CONCLUSION: We suggest that some polyclonal EBV-associated lymphoproliferative disorders develop into polymorphic, but genotypically monoclonal, lymphoproliferative disorders.

Adolescent↗
PubMed1995

Reinforcing effect as a function of infusion speed in intravenous self-administration of nicotine in rhesus monkeys.

The influence of infusion speed on the reinforcing effect of nicotine (NIC) 30 micrograms/kg/infusion was studied in rhesus monkeys using intravenous self-administration at infusion speeds of 5.2, 1.3, and 0.3 micrograms/s under a fixed-ratio 5 schedule with a 15-min time-out after each intake. The 24-h self-administration rate was observed in 3 periods of 8 days each for each speed, separated by saline self-administration periods of 2 weeks each. As a result, when a fixed infusion speed of 5.2 micrograms/s was used throughout the 3 periods, the average rates of NIC were not significantly different each other, but when the infusion speed was changed from 5.2 to 1.3, and then to 0.3 micrograms/s, the average rates significantly decreased. The plasma level following a single-dose infusion of NIC 30 micrograms/kg positively correlated with the infusion speeds. These results indicate that the reinforcing effect of NIC is a function of the infusion speed, most likely through elevation of the peak level of NIC in the plasma.

Animals↗
PubMed1995

The forms and the levels of fecal PMN-elastase in patients with colorectal diseases.

OBJECTIVES: To compare the form of polymorphonuclear leukocyte (PMN)-elastase in feces with that in plasma and to investigate the usefulness of measuring fecal PMN-elastase levels in patients with colorectal diseases. METHODS: We examined PMN-elastase complexed with alpha 1-antitrypsin (alpha 1-AT), chymotrypsin, and alpha 2-macroglobulin by ELISA in feces and plasma. Fecal levels of total PMN-elastase were determined in patients with colonic polyp (N = 19), colonic cancer (N = 20), ulcerative colitis (UC; N = 36), colonic Crohn's disease (CD; N = 26), and in control subjects (N = 20). RESULTS: Most PMN-elastase was not complexed with alpha 1-AT, chymotrypsin, or alpha 2-macroglobulin in feces, whereas most plasma PMN-elastase was complexed with alpha 1-AT. Fecal concentrations and daily fecal excretion of PMN-elastase were significantly increased in patients with active UC (medians 54.8 micrograms/g, 15.14 mg/day) and active CD (41.5 micrograms/g, 10.24 mg/day) compared to those values in control subjects (0.6 micrograms/g, 0.11 mg/day) and in patients with colonic cancer (2.5 micrograms/g, 0.33 mg/day). In inactive UC and CD, these values (3.4 micrograms/g, 0.52 mg/day and 5.2 micrograms/g, 0.59 mg/day, respectively) were significantly lower than in active UC and CD, respectively. In UC, all patients whose rectal biopsies showed infiltration of PMN had high fecal PMN-elastase levels. CONCLUSIONS: Our results suggest that the measurement of fecal PMN-elastase concentrations are useful for monitoring the disease activity of UC and CD, especially when evaluating whether intestinal inflammation has disappeared completely.

Adult↗
PubMed1995

[An autopsy case of Down syndrome in an adult patient with multiple senile plaques and systemic amyloidosis].

A rare adult autopsy case of Down syndrome was reported. The patient was a 36-year-old male, whose chromosome analysis revealed 47, XY, +21. He showed typical systemic AA-amyloidosis and numerous senile plaques in the brain. Senile plaques were diffuse or primitive. They were composed of beta-protein, but negative for Congo-red stain. There were few neurofibrillary changes in the para hippocampal gyri. Nucleus basalis Meynert showed no significant lesion. The distribution of these plaques had some characteristics different from that for Alzheimer's disease. In the brain involvement of systemic AA-amyloidosis was restricted to the regions devoid of blood-brain-barrier, such as choroid plexus and pituitary gland. Cerebral beta-amyloid and systemic amyloid A protein were segregated on each side of the blood-brain-barrier. Therefore, we suggested that each amyloid might be synthesized and deposited by its own mechanism. Electronmicroscopically Hirano's body was identified in the hippocampal gyri.

Adult↗
PubMed1995

[The importance of SpO2 and FIO2 for anesthetic management for Norwood's operation].

The systemic and pulmonary vascular resistance needs to be balanced before cardiopulmonary bypass (CPB) and high flow pulmonary circulation must be avoided after CPB during anesthetic management for Norwood's operation. The level of SpO2 was controlled at 75-80% to maintain systemic and pulmonary circulation. The relationship between the change of color of the lung and level of SpO2 through gradual increase of pulmonary blood flow was carefully observed. As SpO2 level increased, lung changed color from white, pink to red. The SpO2 level of lung in red color was above 85%, suggesting high flow pulmonary circulation. To decrease the level of SpO2, FIO2 was decreased. The lung changed to pink and balance of systemic and pulmonary circulation was maintained, reconfirming that control of SpO2 and FIO2 levels is important for this operation.

Administration, Inhalation↗
PubMed1995

[CD5-negative B-cell chronic lymphocytic leukemia (B-CLL) associated with massive splenomegaly and without lymphadenopathy].

A 39-year-old male was referred to our hospital in June, 1993, because of leukocytosis. Physical examinations showed massive splenomegaly without any lymphadenopathy. The white blood cell count was 13,800/microliters with 87% morphologically mature lymphocytes. Bone marrow aspirate revealed hypercellularity with 67% lymphocytes morphologically similar to peripheral lymphocytes. The lymphocytes displayed monoclonal rearrangements of immunoglobulin genes and the phenotype of CD5-CD19+CD20+ CD21+ and Smlg+. Splenectomy was effective against neutropenia and thromboytopenia. The clinical and laboratory findings of this case were unusual compared to those of typical B-CLL in massive splenomegaly, no lymphadenopathy and CD5-phenotype, suggesting the heterogeneity of B-CLL.

Adult↗
PubMed1995

[Rapid cytology].

The indications for and limitations of rapid cytology were discussed, and intraoperative cytology in combination with frozen section histology was reviewed. During the past 14 years, intraoperative cytology and frozen section histology were simultaneously performed in 1,987 cases of various diseases and organs. A discrepancy between the cytologic and the frozen section diagnoses was noted in 39 (2.0%) instances, and the combined use of cytology and histology was concluded to be useful for correct intraoperative diagnosis owing to their supplementary effect. A rapid preparation and staining technique for intraoperative cytology was described.

Clinical Laboratory Techniques↗
PubMed1995

Automatic measurement of on/off periods of EMG activity.

A computer-based system was designed and implemented for automatically measuring the periods of EMG burst that show periodic but occasionally irregular and large fluctuations in amplitude during mastication. The reliability of the current measuring system was examined. The EMG data was recorded from the inferior orbicularis oris (OI) muscle and the anterior belly of the digastric (DG) muscle by means of surface electrodes. Applying the current method to the human masticatory and perioral muscle activity during chewing revealed that the absolute differences between human- and computer-determined measurements did not differ significantly. We conclude that the proposed measuring system is effective for automatic measurement of on/off periods of EMG burst.

Algorithms↗