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Biomedical subjects

M Komoto

Publications and source records attributed to M Komoto.

35 records · Page 2Linked to original sources
PubMed1990

Electrical myotonia and cataract in X-linked muscular dystrophy (mdx) mouse.

An X chromosome-linked mouse mutant (mdx) has been investigated as an animal model of Duchenne's muscular dystrophy, and has been found to have the same defect of dystrophin in the muscle surface membrane. Intracellular recordings from the mdx mouse hemidiaphragm preparations revealed low resting membrane potentials and electrical myotonia which occurred at the time of microelectrode insertion and withdrawal. Electrical myotonia of the mdx mouse was observed in 30-50% of the impaled muscle fibers at low temperature, which decreased to only 7.8% at 37 degrees C. Electrical myotonia of mdx mice was not abolished by (+)-tubocurarine. Though there was no behavioral myotonia in mdx mice, repetitive bursts of action potentials in mdx mice were based on the abnormalities of the muscle membrane since neuromuscular blockade did not abolish the repetitive bursts. Also close observation of the lenses of mdx mice revealed cataracts from the newborn stage to the adult age. Slit lamp examination of the lenses of the mdx mice revealed nuclear cataracts followed by anterior subcapsular cataract as they grew. The cataract of mdx mice is different from that of myotonic dystrophy which is usually posterior subcapsular.

Animals↗
PubMed1990

Changes in crystallin concentration in rat aqueous and vitreous humors after selenium-induced reversible cortical cataract.

Five months after selenite injection, 58% of the rats that had developed cataract earlier underwent a reversal of the cortical opacity. The purpose of this study was to determine if lenses undergoing recovery from cortical opacity reestablish their ability to retain crystallins. By direct ELISA method, the aqueous humor (AH) of control rats was found to contain 18, 39 and 10 ng/ml alpha-, beta- and gamma-crystallin, respectively, while vitreous humor (VH) contained 43, 98 and 23 ng/ml of alpha-, beta- and gamma-crystallin, respectively. In rats with mature cataracts which did not recover by 5 months after selenite injection, there was an approximately 10-fold greater crystallin concentration in the AH and about 20 times greater crystallin concentration in the VH than in the controls. In contrast, rats undergoing recovery from cortical cataract showed almost normal concentration of crystallins in the AH. While crystallins were still elevated in the VH of the rats undergoing recovery from cortical cataract, the crystallin content was lower than in the rats which did not recover. Higher crystallin concentrations in the VH could be explained by either a greater loss through the posterior capsule, or a slower turnover of VH. Decreased crystallin loss from lenses undergoing recovery suggested that the recovered lens at least partly reestablishes its ability to retain crystallins. These data may demonstrate that the lens fiber permeability is lowered while lens repair is occurring.

Animals↗
PubMed1990

Increase in lens gangliosides due to aging and cataract progression in human senile cataract.

Gangliosides were isolated from human senile cataractous lenses by solvent extraction, DEAE-Sephadex column chromatography, and thin-layer chromatography. The content and composition of gangliosides were examined in individual lens tissues. Three predominant gangliosides, GM3, GM1, and GD1a, were tentatively identified in comparison with authentic brain gangliosides, and several unidentified gangliosides were also recognized. The increase in ganglioside content per mg of protein content in cataractous lenses was found to be influenced by two physiologic parameters: aging and cataract progression. The mature cataractous lenses showed a higher ganglioside level on a protein basis than the immature lenses compared with the same age group. On the basis of statistical analysis, an age-dependent increase in ganglioside concentration was recognized in both mature and immature lens groups. The relative increase in slow-moving polysialogangliosides on thin-layer chromatography seemed to be caused by the maturation of cataract. The sugar composition of one of the polysialogangliosides was found to be glucose, galactose, and sialic acid in the molar ratio of 2:1:4; this suggests the presence of a unique ganglioside species in human cataractous lens.

Adult↗
PubMed1989

[Statistical study of factors related to occurrence and progression of retinopathy in extremely premature infants: especially clinical changes in PaCO2 and pH].

Out of 39 premature infants admitted to the NICU in Toho University Hospital from January 1983 to December 1985 and surviving for 2 months after birth, 22 extremely premature infants who were closely matched in terms of gestational age and body weight at birth were divided into 4 groups (operated group, non-operated A group, non-operated B group and broncho-pulmonary dysplasia (BPD) group) to assess the effect of respiratory management on retinopathy of prematurity (ROP). ROP occurred at a high frequency in extremely premature infants weighing less than 1,000 g. In most of the infants who underwent operation (cryocauterization), PaCO2 values were low for 1 month after birth, whereas pH tended to rise. In the non-operated B group, PaCO2 was almost normal, and pH tended toward acidosis. BPD, which causes severe respiratory disturbance, was observed in 4 cases, 3 of whom showed a rise in PaCO2 within 1 month after birth, but mild ROP. Thus, it was considered that PaCO2 and pH exacerbated ROP.

Carbon Dioxide↗
PubMed1986

Gangliosides in human and monkey lenses.

The amount of gangliosides was determined in normal human lens, cataractous human lens and normal monkey lens. The total gangliosidic sialic acids averaged 176.3 +/- 44.7 (SD) (n = 4) in normal human lenses, and 272.2 +/- 80.6 (n = 14) nmol per gram wet weight in cataractous lenses, respectively; the difference was statistically significant. In monkey lens, the content was 143.8 +/- 32.4 (n = 4) nmol per gram wet weight. The composition of the gangliosides was analyzed by high performance thin-layer chromatography: the components of the a-pathway biosynthesis comprised 78.3% and 70.2%, and those of the b-pathway 13.8% and 20.9%, in the normal and cataractous human lenses, respectively. In the monkey lens, the components of the a-pathway comprised 33.0% and those of the b-pathway were 56.6% of the total gangliosides. Increase in gangliosides was thought to be related with the mechanism underlying formation of cataract.

Animals↗
PubMed1982

Plasma soluble fibrin monomer complexes in the development of diabetic retinopathy.

To elucidate the relationship between plasma soluble fibrin monomer complexes (SFMC) and retinal or vitreous hemorrhages, 11 diabetics were studied for 15 months. The levels of SFMC in 3 out of the 11 cases were elevated prior to hemorrhages and in the other 8 cases SFMC levels were elevated after hemorrhages. With regard to fibrinogen (Fbg) concentrations, there was no significant difference between the values before and after hemorrhages. The plasma glucose levels did not change significantly during the observation. It was concluded that the SFMC level was not only an indicator of the intracapillary generation of thrombin but an important factor affecting the development of diabetic retinopathy.

Aged↗