Biomedical subjects

K Yasukouchi

Publications and source records attributed to K Yasukouchi.

4 recordsLinked to original sources

PubMed2000

Testis developments and puberty in the male Tokara (Japanese native) goat.

In male Tokara (Japanese native) goats, testis development and the onset of puberty were studied histologically and observing sexual behaviour. Testes weight increased from 36+/-5.4 (S.E.) g (n=5) at 3 months of age to 126+/-6.3 g (n=6) at 12 months. The degree of the testis development differed among kids at 3 months of age and only one of four had produced spermatozoa in the testis. Large number of spermatozoa were always present in seminiferous tubules and epididymal ducts from 4 months of age. The diameter of seminiferous tubules increased from 133+/-9.9 microm (n=4) at 3 months to 198+/-1.0 microm (n=3) at 6 months with little increase thereafter. Mounting and pelvic thrusts onto a teaser doe started at from 9 to 14 weeks of age. Ejaculated semen contained sperm with good motility for the first time from 17 weeks. The male Tokara goat reaches puberty at around 4 months of age but testis development continues to 12 months.

Age Factors↗

PubMed1991

[Intracranial fibrous xanthoma (xanthofibroma) in an infant: a case report].

A case of intracranial fibrous xanthoma (xanthofibroma) is reported. Intracranial fibrous xanthoma in infancy under the age of 1 year is extremely rare. This patient was a 8-month-old boy with a history of convulsive seizure. He had a previously known chest wall tumor which was diagnosed as fibrous xanthoma of the skin. Plain CT scan revealed a well defined high density area in the left temporal lobe. The area was well enhanced with contrast media. At operation, it was found that the tumor did not attach to dura mater and was almost well demarcated. Total removal of the tumor was performed. The patient has been doing well for these 6 months following craniotomy, with no sings of recurrence and no neurological deficits. Histologically, the tumor was composed of fibroblastic cells and foamy phagocytic cells in storiform pattern. Some multinucleated giant cells were found. Immunohistochemistry technique revealed that the tumor cells were negative for GFAP, positive for Vimentin, positive for S-100 protein and negative for EMA. Our studies support the diagnosis of intracranial fibrous xanthoma coexistent with the same tumor found in the subcutaneous space of the chest wall of a boy under 1 year of age. We regard it as a rare incidence. Differential diagnosis and the characteristics of fibrous xanthoma were discussed.

Brain Neoplasms↗

PubMed1990

Enzyme immunosensors based on electropolymerized polytyramine modified electrodes.

Highly sensitive amperometric enzyme immunosensors for human immunoglobulin G (IgG) were prepared on the basis of electrogenerated polytyramine (PTy, tyramine = p-(2-aminoethyl)-phenol) modified electrodes. Properties of PTy films changed depending on electrolysis conditions. On the basis of the found properties of the films, an effective IgG sensor was prepared: a PTy film was formed first from an acid solution on a Pt electrode, and the surface was further covered with a PTy film from an alkaline methanol solution to give a PTy doubly coated electrode on which anti-IgG was then immobilized. This electrode provided a large surface area with little non-specific adsorption of proteins. By means of the competitive enzyme immunoassay technique using glucose oxidase (GOD) labeled IgG conjugates, IgG was determined in the concentration range of c. 10 pg/ml-1 mg/ml from the oxidation current of H2O2 generated by the enzyme (GOD) reaction using the above IgG sensor. Also, an anti-IgG immobilized electrode, prepared by using a Pt electrode singly covered with a PTy film from an alkaline methanol solution, acted as an effective IgG sensor with a detection limit for IgG of c. 100 pg/ml.

Antibodies, Anti-Idiotypic↗

PubMed1981

Tolerance to and dependence on barbiturates in mice reference to the data in rats.

The experimental results on tolerance to and dependence on phenobarbital (PhB) in male, ICR mice were compared with results previously reported in the case of rats. When food admixed with 1 and 2 mg PhB/g food was administered daily for 13 consecutive days, the mice began to acquire tolerance to PhB from the 4th day or so (rotarod performance test), with little suppression being observed on days 6 or 7. These results indicate that tolerance to PhB is acquired earlier in mice than in rats. The blood and brain concentrations of PhB during the dosing period were reduced abruptly on the 3rd or 4th day, corresponding well with the time course changes in the development of tolerance shown by rotarod performance. The mice were given daily doses of PhB increasing stepwise from 0.5 and 1 mg PhB/g food to 4 mg PhB/g food, over 39 consecutive days. With this gradually increasing dose regimen, the animals maintained moderate to severe depression of CNS throughout the dosing period. The blood and brain half-life of PhB after withdrawal were 16 and 8 hr respectively. From 17 to 24 hours after withdrawal of PhB, the animals showed signs of systemic tremors, Straub-tail, hyperkinesia, wild running "rum fits" and clonic-tonic convulsions. Contrary to the findings in rats, in which there was a frequent incidence of convulsion from 17 to 48 hours after withdrawal, the duration of the characteristic signs after barbiturate withdrawal was obviously short-term. These results suggest that may be more reasonable to use rats in preference to mice as a preclinical model of dependence, especially in cross-physical dependence tests for sedative-hypnotic drugs.

Animals↗