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Biomedical subjects

Y Takeuchi

Publications and source records attributed to Y Takeuchi.

At least 739 records · Page 41Linked to original sources
PubMed1990

Japanese encephalitis in a 7-month-old Japanese boy.

A 7-month-old Japanese boy was diagnosed as having meningo-encephalitis with anterior horn cell damage. The complement fixation (CF) and hemagglutination inhibition (HI) tests showed increased antibody titers against Japanese encephalitis (JE) virus, but HI antibody in the mother's serum was not increased. It appears that the lack of JE-antibodies from the mother may have resulted in increased JE viral infectivity in the patient. A decrease in the incidence of antibodies against various viruses in women of childbearing age may lead to increased rates of severe viral infection in infants.

Complement Fixation Tests↗
PubMed1990

Massive fetomaternal hemorrhage: case report.

Massive fetomaternal hemorrhage (FMH) is rare. Early diagnosis is important because FMH has a poor prognosis in the antepartum or early postpartum period. A case of massive FMH in which 400 ml blood was lost is presented here. Fetal anemia was suspected from the sinusoidal fetal heart rate pattern. The hemorrhage in the maternal circulation was diagnosed before delivery by using the Kleihauer-Betke test. An emergency cesarean section was performed. The cord hemoglobin level was 3.7 g/dl. The baby's severe anemia was treated with a neonatal blood transfusion. In this case, the baby had a good clinical course. Early diagnosis and treatment of massive FMH are necessary for a good prognosis.

Adult↗
PubMed1990

HLA-D region genomic polymorphism associated with Takayasu's arteritis.

Takayasu's arteritis, with a strong predilection for women and particular geographic areas, has revealed significant association with human lymphocyte antigens (HLA) specificities. In the present study, the authors investigated for the first time the association of Takayasu's arteritis and HLA at the genomic level. By use of a restriction endonuclease Taq-I and a DQA cDNA probe, HLA-D region restriction fragment length polymorphism was examined in 32 Japanese patients. It was revealed that 65.6% of the patients shared a 6.6 kb fragment, although this fragment was found in 35.3% of the healthy Japanese (Chi square: 6.07, p less than 0.02). This finding suggest that HLA-D region gene variations determine susceptibility to Takayasu's arteritis.

Adult↗
PubMed1990

Relation of disposition kinetics to pharmacological effect of intravenous administration of chlorzoxazone in rats.

The quantitative relationship between a drug disposition and the pharmacological effect was examined in rats using chlorzoxazone (CZX), a centrally acting muscle relaxant, as a model drug. After intravenous administration of CZX, the decay of the plasma concentration was rapid and it was found that CZX obeyed one compartment open model in the dose range of 5 to 25 mg/kg studied. The pharmacological response intensity was determined by means of the crossed extensor reflex. The duration of the muscle relaxant effect was proportional to the logarithm of the dose of CZX. The time course of the calculated plasma concentration was well related to the pharmacological response intensity via a Hill's equation and the simulated pharmacological response intensity which was obtained by means of the equation was coincident to the time course of the response data. These results indicated that the time course of pharmacological response intensity was able to be predicted using the time course of plasma concentrations. From the analysis of the quantitative relationship between the concentration and the effect under the present experimental conditions studied, it was found that the biophase compartment was identical to the central compartment as long as the first order processes were proceeding. These findings implied that the time course of pharmacological response would be quantitatively predictable from the disposition kinetics of CZX after the intravenous administration.

Animals↗
PubMed1990

Synthesis and antitumor activity of fused quinoline derivatives.

Some tetracyclic quinolines (9 and 14) with a [2-methoxy-4-[(methylsulfonyl)amino]phenyl]amino side chain were prepared and their deoxyribonucleic acid (DNA) intercalative properties, KB cytotoxicity, antitumor activity (P388 leukemia), and ability to induce topoisomerase II dependent DNA cleavage were investigated. The indoloquinoline derivative 9 exhibited the most potent activity (dose = 6.3 mg, T/C% = 300) in this series. The steric structural features of the chromophores of the compounds previously and newly synthesized were studied by a computer-associated molecular graphics technique. Relationships between the steric structural features of the chromophores and biological activities are also discussed.

Animals↗
PubMed1990

Syntheses and antifungal activities of dl-griseofulvin and its congeners. I.

dl-Griseofulvin (1a) was prepared by two synthetic pathways. New 6'-congeners (3 and 4) of griseofulvin were also prepared. Their antifungal activities were evaluated and compounds 3 and 4 were found to be less active than 1a. Molecular calculations on 1a, dl-epigriseofulvin (1b), 3 and 4 were undertaken.

Antifungal Agents↗
PubMed1990

[Effect of cefaclor on guinea pig platelet aggregation in vitro].

Effects of cefaclor (3-chloro-7-D-(2-phenyl-glycinamido)-3-cephem-4-carboxylic acid) on PAF, ADP, collagen, endotoxin, and thrombin-induced platelet aggregation were examined in vitro with the use of guinea pig platelet-rich plasma and washed platelets. PAF, even at concentrations lower than its minimum effective concentration, enhanced ADP- or endotoxin-induced platelet aggregation and prolonged the time to attain the maximum aggregation. PAF also enhanced collagen-induced platelet aggregation and shortened the lag time. Cefaclor (CCL) inhibited the PAF, ADP or thrombin induced platelet aggregation and shortened their maximum aggregation times at higher concentrations such as 300 micrograms/ml or more. CCL also inhibited the collagen-induced platelet aggregation and prolonged the lag time, but showed no effect on endotoxin-induced platelet aggregation. The effect of CCL was almost the same as that of latamoxef (LMOX). CCL and LMOX, however, showed no effect on cellular Ca2+ increase produced by PAF, ADP, or thrombin, suggesting that the inhibitory effect of CCL and LMOX on platelet aggregation is caused by the inhibition of fibrinogen binding to the glycoprotein IIb/IIIa complex.

Adenosine Diphosphate↗
PubMed1990

Stereotaxic approach to hypothalamic nuclei of the Shiba goat with radiographic monitoring.

Practical method was devised for precise approach to hypothalamic nuclei in the Shiba goat. A stereotaxic instrument and a brain atlas with stereotaxic coordinates were developed. For an accurate placement of probes into specific hypothalamic regions a radiographic method was employed in which radio-opaque material was injected into the lateral ventricle and the ventricular outline was depicted. A sagittal diagram showing the arrangement of hypothalamic nuclei in relation to the brain ventricular system was constructed from the transverse stereotaxic atlas. This diagram was revealed extremely useful in pinpointing the target on the radiographs of lateral view. Precision of this method was evaluated in female Shiba goats (n = 4) by comparing radiographically estimated positions of hypothalamic nuclei with those histologically determined. Despite of cranial variability among individual animals these two parameters matched well each other in all the nuclei examined. Furthermore, chronic cannulae were implanted into different hypothalamic structures of one goat and the accuracy of their placement was confirmed histologically. Thus, it was revealed that the stereotaxy by aid of radiography herein described was accurate enough to apply to various neuroendocrinological studies in the Shiba goat.

Animals↗
PubMed1990

Thyroid hormone excess stimulates the synthesis of proteoglycan in human skin fibroblasts in culture.

We previously demonstrated that proteoglycan accumulated in the affected skin of circumscribed pretibial myxedema of Graves' disease. As an underlying mechanism responsible for the accumulation, we sought to determine whether excess thyroid hormone was partially responsible for the increase in proteoglycan synthesis. Human skin fibroblasts were cultured in Ham's F-10 medium containing 1% Nutridoma with graded doses of T3 (0.184 x 10(-9) to 46 x 10(-9) mol/l) and were labelled with [35S]sulphate and [3H]glucosamine. Proteoglycans were purified by Sephadex G-50, Q-Sepharose chromatography with NaCl-gradient and Sepharose CL-6B chromatography. 35S and 3H incorporated into dermatan sulphate proteoglycan and heparan sulphate proteoglycan and 3H incorporated into hyaluronan were measured. 35S and 3H incorporation into dermatan sulphate proteoglycan was minimum at a T3 concentration of 0.184 x 10(-9) mol/l, and increased with increasing doses of T3 up to 46 x 10(-9) mol/l. 35S and 3H incorporation into heparan sulphate proteoglycan also increased with increasing-doses of T3. 3H incorporation into hyaluronan was not influenced at all by T3. The increased incorporation of 35S into proteoglycan in high-T3 culture reflects the increased synthesis of proteoglycan because 1. the extent of sulphation of disaccharides examined by thin-layer chromatography was not altered by T3; 2. the specific activity of [35S]sulphate was not influenced by T3, and 3. T3 did not decrease the degradation rate of cell-associated proteoglycan.

Adolescent↗
PubMed1990

[Studies on O'Leary's plaque control record in initial periodontal treatment. 1. Relation between PCR and different brushing methods in 1982-1986].

The purpose of this study was to investigate the effects of different methods of brushing on plaque removal, using O'Leary's plaque Control Record during initial preparation. The results were as follows: 1. There were many 40-50 year-old patients and they showed a 63.0 percent first visit Plaque Control Record average. 2. Many of the patients entering the clinic had periodontal disease in mild stages. 3. In most cases the toothbrushing methods were the Rolling method and the Modified Stillman's method. Of the patients, 73.5% achieved Plaque Control scores at the 20 percent level. 4. Of the patients who had achieved a Plaque Control Record at the 20 percent level, half of the patients instructed to brush using the Rolling method had developed moderate forms of periodontal diseases, and half of the patients instructed to use the Modified Stillman's method had developed mild forms of periodontal disease. There is a close relationship between toothbrushing methods and the progression of diseases, and this shows that Plaque removal methods should be controlled.

Adult↗
PubMed1990

[Mechanical impedance of the human mastoid and forehead--a critique of the mechanical coupler of the IEC373].

Mechanical impedances of human mastoids and foreheads were measured on frequencies from 250 to 6300 Hz for 80 young adults by means of B&K impedance head (#8000) and shaker (#4810) as main parts of the measuring setup. The measurements revealed the following problems in the IEC373 (1971/1981) which had defined the mechanical impedance characteristics of the mechanical coupler for calibration of bone vibrators in audiometric use. The average impedance levels of the mastoids differ significantly from those of the foreheads in middle and high frequencies. The impedance levels of the IEC373 mechanical coupler are higher than those of the present measurements of the mastoids and the foreheads. The differences exceeded the tolerance limits of IEC373 (1981) in every frequency. These findings strongly suggest that the coupler is neither the artificial mastoid nor the artificial forehead but a coupler having a specified impedance, therefore, disregard for effect of the type of bone vibrator on the Reference Equivalent Threshold Force Level, as seen in ISO7566, should be revised and that the RETFL should be determined for an each type of bone vibrator.

Adult↗
PubMed1990

[Five-choice speech discrimination test].

In order to overcome defects of dictation method, a new 5-choice method introduced into Japanese mono syllables discrimination test. A new 20-items mono syllables list was developed on the principle of equal probability of the Japanese consonant phonetics, instead of the present mono syllable frequencies among the 100 Japanese mono syllables. The choice items for the each stimulus syllables were selected on the analysis of perceptual confusions data among hard of hearing persons. Comparison of discrimination scores and consonant confusions of the dictation method speech test and 5-choice method revealed that the two tests were parallel with some advantages of easiness of test procedure, and easiness and objectivity of scoring on the side of 5-choice method.

Humans↗
PubMed1990

SF2487, a new polyether antibiotic produced by Actinomadura.

A new antibiotic SF2487 has been isolated from the culture broth of Actinomadura sp. SF2487. The structure of antibiotic SF2487 was determined by spectroscopic analyses of the sodium salt and X-ray diffraction analysis of the silver salt. The antibiotic represents a new member of polyether group antibiotics known as the acyltetronic acid type 4. The antibiotic is weakly active against Gram-positive bacteria and exhibits antiviral activity against influenza virus in vitro.

Animals↗
PubMed1990

MK4588, a new antibiotic related to xanthocillin.

A new antibiotic, MK4588, structurally related to xanthocillin, was isolated from the culture broth of Leptosphaeria sp. L-179. Antibiotic MK4588 exhibited inhibitory activity against a limited range of Gram-positive and Gram-negative bacteria. The antibiotic was degraded by alkali to a more active product. The structures of MK4588 and the degradation product were determined to be (1R*,6S*,7S*)-7-(Z)-(1-isocyano-2-(4-methoxyphenyl]ethenyl-1-hydro xy-7- isocyanobicyclo[4,2,0]oct-2-en-4-one and (Z)-2,3-diisocyano-1-(4-methoxyphenyl)buta-1,3-diene, respectively, by NMR spectral analyses coupled with X-ray crystallographic analysis of MK4588.

Anti-Bacterial Agents↗
PubMed1990

[An evaluation of 3-dimensional position of mandibular condyle to glenoid fossa using tomogram: an analytical technique and its clinical application].

In recent years, temporomandibular disorder (TMD) is occasionally found among orthodontic patients and has become a great concern in orthodontics. From this point of view, a certain technique has been hopefully anticipated for diagnosis and treatment planning. The purpose of this study was to develop a new method for evaluating three-dimensional position of the mandibular condyle relative to the glenoid fossa and also to investigate its clinical application. Seven-layered tomograms were taken and contours of the condyle and glenoid fossa were traced on an acetate paper. These contours were entered into a personal computer by use of a digitizer and were equally divided into 9 parts for the condyle and 15 parts for the glenoid fossa, consisting of 10 and 16 points on the contours of condyle and glenoid fossa. Three-dimensional configuration of the TMJ was thus constructed by 108 triangles for the condyle and 180 triangles for the glenoid fossa. The shortest distance between the condyle and the glenoid fossa (CGFD) was then calculated along a perpendicular line to center of gravity of a triangle on the condyle. For evaluating the position of the condyle to the glenoid fossa easily in a three dimensional space, surface of the condyle was divided into five areas, i.e. anterior, posterior, middle, lateral and medial areas. In order to investigate whether or not the CGFD is accurate enough to identify the distance between surface of the condyle and glenoid fossa, a model of hemi-spherical solid shell was made, of which the thickness is 3.0 mm. Tomograms of the model were taken to analyze the thickness. Direct measurement of the same area was also made by calipers. Two means were approximately 3.0 mm, which is the thickness itself and no significant differences were indicated at 5% level of confidence. The present technique was applied to diagnosis of an orthodontic patient with painful clicking as TMD. The analyzed CGFDs were coincident with clinical symptom. It is shown that the present approach provides an availability and a possibility to evaluate positional relationship between the mandibular condyle and the glenoid fossa of patients with TMDs.

Humans↗
PubMed1990

[A case report of Ebstein's anomaly treated with Carpentier's procedure].

A 42-year-old male patient was admitted with congestive heart failure. Echocardiogram and cardiac angiogram revealed Ebstein's anomaly and severe tricuspid valve incompetence. He underwent Carpentier's procedure for the treatment of Ebstein's anomaly. Carpentier's procedure consists of the following two new points; (1) the right atrium and atrialized ventricle is plicated longitudinally; (2) the anterior leaflet and the posterior leaflet of tricuspid valve are transposed with a clockwise rotation to the level of the normal tricuspid anulus. Compared with Hardy's procedure (transverse plication), longitudinal plication preserves the cavity and the function of the right ventricle and excludes atrialized chamber. In our case, there is a trivial residual regurgitation of tricuspid valve postoperatively, but the patient's clinical status has improved remarkably. We conclude that Carpentier's procedure is an effective operation for Ebstein's anomaly.

Adult↗