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Biomedical subjects

K Takamura

Publications and source records attributed to K Takamura.

At least 19 recordsLinked to original sources
PubMed1992

Cardiovascular anomalies in chick embryos produced by bis-diamine in dimethylsulfoxide.

N,N'-bis(dichloroacetyl)-1,8-octamethylenediamine(bis-diamin e) (100 micrograms) dissolved in dimethylsulfoxide (DMSO) was administered to early developing chick embryos (Hamburger-Hamilton stage 9-21) in order to clarify the teratogenic effects on the cardiovascular system and to determine whether bis-diamine interferes with the migration of neural crest cells. Of 346 cases, 154 (44.5%) survived. The incidence of cardiovascular anomalies was 149 out of 154 cases (96.8%). Infundibular ventricular septal defect, double outlet right ventricle, and persistent truncus arteriosus were the primary cardiac anomalies observed in this study. A high percentage of these anomalies were accompanied by hypoplasia of the right 6th aortic arch artery and persistent left 4th aortic arch artery. Particularly, administration of bis-diamine to chick embryos at stage 13 resulted in a high incidence of persistent truncus arteriosus (64.3%). Bis-diamine has been suspected to inhibiting the migration of neural crest cells. However, neural crest cells were observed in the tunica media of the great arteries and the truncal valves of persistent truncus arteriosus produced by bis-diamine in chimeric embryos at stage 13. Morphological changes such as cell death were not observed.

Abnormalities, Drug-Induced↗
PubMed1992

[Flow injection analysis for determination of choline-containing phospholipids by luminol chemiluminescence].

A sensitive flow injection analysis using luminol/peroxidase chemiluminescence was developed for the determination of choline-containing phospholipids in serum. Flow injection manifold was composed of two channel system with an enzyme column, in which phospholipase D was immobilized together with choline oxidase. The serum sample (5 microliters) was pretreated by Extrelut column (diatomite column) extraction with chloroform-methanol (95:5). The extract (20 microliters) was injected into a sample carrier at 38 degrees C and passed through the enzyme column, which converted phospholipid to choline and subsequently to hydrogen peroxide. Produced hydrogen peroxide was monitored by measuring the chemiluminescence intensity of luminol/peroxidase system at 5 degrees C. The response was linear against the amount of phospholipids ranging from 2 to 2000 pmol/test, and the relative standard deviation was less than 2%. In the determination of phospholipids in the serum, a correlation coefficient (r) between 4-aminoantipyrine/phenol and the proposed methods was found to be 0.983 (Y = 1.035X-6.2). The throughput rate was 15 samples/h.

Blood Chemical Analysis↗
PubMed1992

Field trials on a live bovine respiratory syncytial virus vaccine in calves.

Field trials were carried out in calves using a live bovine respiratory syncytial (BRS) virus vaccine prepared from the attenuated BRS virus, strain rs-52. Two hundred seventy-five and 353 calves were vaccinated intranasally and intramuscularly, respectively. No undesirable postvaccinal reactions were observed in the vaccinated calves. Of the serum neutralizing (SN) antibody negative calves 89.7% (26/29) and 92.8% (90/97) developed SN antibody 1 month after intranasal and intramuscular vaccination, respectively. Most of the calves having SN antibody titers of 1:1 or 1:2 at the time of vaccination showed a significant increase in SN antibody titer. About 70% and 90% of the calves vaccinated intranasally and intramuscularly, respectively, maintained SN antibody for 6 months after vaccination. In a field trial, a natural BRS virus infection occurred about 5 months after the start of the trial. Ten of the 16 unvaccinated control calves showed respiratory symptoms due to BRS virus infection. On the contrary, all of the 68 vaccinated calves exhibited no symptoms at all, indicating efficacy of the vaccine.

Animals↗
PubMed1990

Association of cephalic neural crest cells with cardiovascular development, particularly that of the semilunar valves.

The quail-chick chimera method was used to examine whether neural crest cells were associated with the formation of semilunar valves. From the metencephalon to somite 5, or from the otocyst to somite 3, left, right, or bilateral neural folds, including the neural crest, were transplanted. Among embryos used for the experiment, three into which left neural crest cells were transplanted, two into which right neural crest cells were transplanted, and two into which bilateral neural crest cells were transplanted had a morphologically normal heart. In these embryos, neural crest cells were found in all cusps of the aortic and pulmonary semilunar valves. Although neural crest cells have been thought to have no association with the formation of the semilunar valves, our experiment indicates that such association indeed occurs.

Animals↗
PubMed1990

Fluorometric determination of pseudocholinesterase activity in postmortem blood samples.

A fluorometric assay using 3-(p-hydroxyphenyl) propionic acid (HPPA) was conducted to determine the activity of pseudocholinesterase (ChE) [Enzyme Commission (EC) No. 3.1.1.8] in postmortem blood samples so as to test for organophosphate poisoning. By the enzymatic reaction of ChE, its substrate, benzoylcholine, produces choline, which is oxidized by choline oxidase to generate hydrogen peroxide. HPPA is oxidized by hydrogen peroxide and peroxidase to become the fluorogenic dimer whose concentration is measured fluorometrically at an excitation emission wavelength of 320 nm and an elimination emission wavelength of 404 nm. The selectivity and sensitivity of the present method were found to be superior to those of conventional pH and spectrophotometric methods.

Butyrylcholinesterase↗
PubMed1989

[Intraocular fluid antibody quotients following inoculation with two different antigens in experimental herpes simplex virus retinochoroiditis].

Viral retinochoroiditis was induced experimentally by inoculation of herpes simplex virus into the vitreous body in rabbits. The animals were sensitized systemically using 2 pathogens as antigens (herpes simplex virus and toxoplasma gondii) 3 weeks prior to intraocular inoculation. Serum and intraocular fluid were collected 2 weeks after inoculation. The intraocular fluid antibody titers and quotients for these 2 pathogens were then measured to determine the effects of serum antibodies, which are thought to enter the eyes as a result of destruction of the blood-ocular barrier. Experimental criteria for antibody quotients were also determined. Antibody quotients for the etiological virus (herpes simplex virus) ranged from 2 to 20, with an average of 9.7. Those for toxoplasma gondii, the antibody of which is thought to enter the eye from the blood, were all less than 5 with average of 1.9. From these results, it would seem that when the antibody quotient of a pathogen in more than 6 in the intraocular fluid, it is likely to be an etiological organism, while the possibility of infection is very low when the quotient is under 2. More precise studies are required to identify an etiological pathogen when the quotient is 2-6.

Animals↗
PubMed1988

Changes in body proportions of Japanese medical students between 1961 and 1986.

Since 1945, the Japanese physique has changed a great deal. Physical examinations of medical students at Kyushu University have been carried out on an annual basis since 1939. We investigated changes in body proportions using data on 813 medical students examined from 1961 to 1986. During these 26 years, standing height has increased by 4.69 cm, arm length by 2.58 cm, and sitting height by 0.79 cm. Thus, the Japanese have grown taller and their extremities are longer, yet the trunk has not changed significantly. This study also shows a 10-year delay in increase in length of the upper extremities.

Adult↗
PubMed1987

Expression of epidermis-specific antigens during embryogenesis of the ascidian, Halocynthia roretzi.

We have produced two monoclonal antibodies (Epi-1 and Epi-2) which specifically recognize epidermal cells and their derivative, the larval tunic, of developing embryos of the ascidian Halocynthia roretzi. The antigens, examined by indirect immunofluorescence staining, first appear at the early tailbud stage and are present until at least the swimming larval stage. There were distinct and separate puromycin and actinomycin D sensitivity periods for each antigen. Aphidicolin, a specific inhibitor of DNA synthesis, prevented the appearance of each antigen when embryos were exposed to the drug continuously from cleavage stages. These results suggest that the antigens are synthesized during embryogenesis by developing epidermal cells and that several rounds of DNA replication are required for the antigen expression. Early cleavage stage embryos, including fertilized but unsegmented eggs, in which cytokinesis had been blocked with cytochalasin B expressed the antigens, and blastomeres exhibiting the antigens were always of the epidermis lineage. In partial embryos produced by four separated blastomere pairs of the 8-cell embryos, the expression of antigens was seen only in those developed from the animal blastomere pairs, which are progenitors of epidermal cells. These observations indicate that differentiation of epidermal cells in ascidian embryos takes place in a typical "mosaic" fashion.

Animals↗