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Biomedical subjects

M Itoi

Publications and source records attributed to M Itoi.

At least 37 records · Page 2Linked to original sources
PubMed1989

[A cataract classification and grading system].

A cataract classification and grading system developed for cataract epidemiological survey was introduced. Cataractous opacities were classified into cortical, nuclear and subcapsular types. Gradings of cataract progression were divided into early (Grade I), moderate (II) and advanced (III) stages. The grading of cortical opacity was judged by the opaque area in a maximally dilated pupillary zone of which findings were obtained from a red-reflex image. The grading of nuclear opacity was judged from the intensity of scattering light at the nucleus. Three grading steps were based on the densitometrical analysis of photographed images. Subcapsular opacities were classified into three gradings by extensions up to the normal, moderately dilated and maximally dilated pupil size. Regarding cortical and unclear cataracts, standard images indicating border findings between Grades I and II and Grades II and III were provided to help with classification. Nuclear coloration was classified into pale yellow, yellow, brownish yellow and brown including reddish brown and black brown. To document cataractous findings, a recording chart was made.

Cataract↗
PubMed1989

Specular microscopic studies of the corneal endothelia of Japanese diabetics.

We did a specular microscopic study with computer-assisted morphometric analysis of individual cells on the corneal endothelia of 69 Japanese diabetics and 53 age-matched nondiabetics. No statistically significant differences were seen in the mean cell areas of diabetics and nondiabetics. However, the coefficient of variation of cell area was significantly higher and the percentage of hexagonal cells was significantly lower in diabetics than in nondiabetics. Although racial differences of the corneal endothelia exist between Japanese and Americans, diabetic changes are quite similar in the two populations.

Adult↗
PubMed1988

Neuronal responsiveness in area 21a of the cat.

Photic responsiveness was studied in cells of area 21a which was identified as a region containing few cells projecting to area 17, and was bounded to two other visual areas (posteromedial lateral suprasylvian area and area 19) providing abundant efferent projection to area 17. Area 21a cells were characterized by strong orientation, but demonstrated poor direction and end-stop selectivity, in contrast to strong direction or end-stop selectivity of cells in another two visual areas.

Animals↗
PubMed1988

Changes in nuclear DNA content and cell size of injured human corneal endothelium.

To understand how human corneal endothelium compensates for cell loss, nuclear DNA-cytofluorometry and cell morphometry were carried out on injured corneal endothelium. The examined corneas included two cases of keratoconus complicated with acute hydrops and one without acute hydrops, two cases of herpetic keratitis, one case of post-intracapsular cataract extraction (post-ICCE) and one case of luetic keratitis. The endothelial cell layer was separated from Descemet's membrane and double-stained with Rhodamine-labeled wheat germ agglutinin-lectin (WGA) and 4',6-diamidino-2-phenylindole dihydrochloride (DAPI). The area of each cell was measured with a color image analyser and compared with its cytofluorometric nuclear DNA content. The endothelium in apparently intact regions of the diseased corneas showed the same DNA-ploidy pattern and cell area as the physiological corneas. However, endothelial cells in injured regions had greater area, even in diploidy, than in presumably normal ones and showed a larger number of hyperploid cells ranging from 4C to 36C. Hyperploid cells consisted of many multinucleates and few polyploidies and had extremely large and bizarre cytoplasm. All injured corneas were accompanied by cells with numerous micronuclei. A few asymmetrical 4C-binucleates (with DNA values such as 1.3 plus 2.6C) appeared in the case of the post-ICCE. It is concluded that damage to human corneal endothelial cells in vivo results in cell enlargement with or without DNA synthesis. Those changes appear more severe in diseased corneas than in the situation of physiological aging which we have reported previously. In severe cases, micronuclei, polyploid cells and multinucleated giant cells are frequent, thereby suggesting a possible long-persistent metabolic impairment of the endothelium after severe damage to the cornea.

Adolescent↗
PubMed1986

Age-dependent changes in nuclear DNA content and cell size of presumably normal human corneal endothelium.

In order to investigate a relationship between cellular DNA-content and enlargement in cell size of human corneal endothelium in healthy population, both nuclear DNA-cytofluorometry and cell morphometry were performed on individual cells of presumably normal corneas taken from six autopsy cases. The cornea was treated in 0.2 M phosphate buffer containing 60 mM Na2EDTA and fixed with absolute methanol. The endothelial-cell layer was separated from Descemet's membrane by placing the tissue in distilled water. The specimen was marked with rhodamine-labelled wheatgerm agglutinin (WGA)-lectin for identifying cell boundaries and subsequently stained with DAPI for measurement of DNA contents. The area of each cell was measured by means of a color image analyser and compared with its cytofluorometric nuclear DNA content. The enlarged endothelial cells which appeared with age contained diploid, polyploid or multiple nuclei. The polyploid and multinucleated cells had larger mean and maximum cell sizes and more irregular and polymorphous shapes than diploid cells. There were neither small polyploid nor small multinucleated cells. It was suggested that the loss of human corneal endothelium was compensated in vivo by cell size enlargement with or without doubling of nuclear DNA.

Adolescent↗