Biomedical subjects

H Kuno

Publications and source records attributed to H Kuno.

9 recordsLinked to original sources

PubMed1992

Usefulness of ophthalmic examination in postnatal observation in teratology studies.

Pregnant rats were irradiated with soft x-ray at a dose of 635 r or 1270 r on Day 9 or 11 of gestation. The eyes of F1 offspring were examined by indirect ophthalmoscopy and slit lamp biomicroscopy in postnatal weeks 3 to 7. Ophthalmoscopic examination of offspring irradiated at a dose of 635r or 1270r on Gestational Day 9 revealed iris and choroidal coloboma together with microphthalmia and anophthalmia at Postnatal Week 3 or later. Choroidal coloboma, an anomaly that cannot be detected by the common external observation method, was found ophthalmoscopically in one rat without any external ocular abnormalities. This fact suggests that ophthalmoscopy in postnatal observation can be useful to detect ocular teratogenic potential of test compounds in preclinical safety studies.

Abnormalities, Radiation-Induced↗

PubMed1991

Stratum corneum lipids serve as a bound-water modulator.

Stratum corneum lipids have been found to be an important determinant involved in the water-holding function of the stratum corneum. In order to further elucidate the significance of stratum corneum lipids in the water-holding properties, the hydration behavior of the stratum corneum following depletion and replenishment of the lipids has been studied, using an isolated human forearm stratum corneum sheet, by differential scanning calorimetry parallel to ultrastructural changes of intercellular lipids in the stratum corneum. Extraction of the stratum corneum sheet with acetone/ether (1/1) decreased the bound-water content from 33.3% to 19.7%, where the melting temperature of ice remained constant. Further extraction with water, which released a large amount of water-soluble materials such as amino acids, did not change the bound-water content, but definitely raised the melting temperature of ice. The application of the stratum corneum lipids, which were solubilized in squalane containing 1% alpha-monomethyl heptadecyl glyceryl ether to the lipid-depleted stratum corneum sheet, caused a significant recovery of bound-water content to the previous, almost normal level. In accordance with the hydration behavior, electron microscopic analysis of the acetone/ether-treated stratum corneum sheet revealed selective depletion of lipids from the intercellular spaces, accompanied by a marked disruption of multiple lamellar structures. In contrast, the application of stratum corneum lipids into the lipid-depleted stratum corneum sheet resulted in the restoration of the lamellar structure between the stratum corneum cells. These findings strongly suggest that stratum corneum lipids serve a water-holding function through the formation of lamellar structures within the stratum corneum.

Adult↗

PubMed1991

Spontaneous ophthalmic lesions in young Sprague-Dawley rats.

Eight hundred eight Sprague-Dawley rats were examined for ophthalmic abnormalities during a pretest period in various preclinical safety assessment studies. Persistent pupillary membrane, corneal crystal, healed minor trauma, synechia, coloboma of the iris, lens luxation, cataract, persistent hyperplastic primary vitreous, vitreous hemorrhage, coloboma of the optic disc or choroid, remnant of hyaloid arterial system, retinal hemorrhage, retinal detachment, retinal folding and choroidal defect were observed. The incidences of corneal crystal, synechia, and nuclear cataract in this survey were higher than those reported previously. On the other hand, retinal folding in this survey was less common than that reported previously. These results suggest that background data of eye problems in albino rats should be accumulated in each own laboratory colony. In addition, since spontaneous eye problems are common in young albino rats, elimination of rats with ophthalmic abnormalities from study groups by an ophthalmic examination during a pretest period would facilitate to evaluate toxicity potential of test compounds in safety assessment studies.

Animals↗

PubMed1988