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Biomedical subjects

A Kanai

Publications and source records attributed to A Kanai.

At least 127 records · Page 7Linked to original sources
PubMed1991

Glutathione and glutathione-related enzymes in human cataractous lenses.

Glutathione and its related enzymes were measured for normal and cataractous human lenses. Glutathione decreased progressively with the development of cataracts. This decrease was more pronounced in the nucleus than in the capsule-epithelia of cataractous lenses. Glutathione reductase in nuclear extracts was relatively unchanged during cataract progress, while glutathione synthetase was significantly low in the advanced stages of cataracts. gamma-Glutamylcysteine synthetase was not measurable in the nuclei of cataractous lenses.

Aged↗
PubMed1991

Repolarization inhomogeneities in ventricular myocardium change dynamically with abrupt cycle length shortening.

BACKGROUND: In single heart cells, abrupt changes in stimulation rate elicit complex alterations in repolarization. The effects of rate change on dispersion of repolarization, however, have not been well characterized. METHODS AND RESULTS: To determine the effects of abrupt cycle length (CL) shortening on spatial inhomogeneity of repolarization in a syncytium of ventricular cells, 124 action potentials were simultaneously recorded from Langendorff-perfused guinea pig hearts using high-resolution optical mapping with voltage-sensitive dye. The distribution of ventricular action potential durations (APDs) mapped during each cardiac cycle was used to calculate mean APD and repolarization dispersion index (DI), defined as the variance of the distribution. After abruptly shortening CL from 500 to 300 msec, mean APD declined exponentially in normoxic controls (by 23 +/- 3 msec, p less than 0.0001). This response was characterized by beat-to-beat oscillations of APD that were synchronized at all ventricular sites. After 30 minutes of hypoxia, mean APD decreased from 175.0 +/- 13.3 to 76 +/- 25.7 msec. However, during hypoxia, abrupt CL shortening lowered mean APD by only an additional 6 +/- 6 msec, and APD oscillations were no longer synchronized throughout the ventricle. In controls, beat-to-beat DI decreased significantly (-51.0 +/- 6.8%, p less than 0.01) by the sixth post-CL shortening beat and then recovered (by 15-20 beats). In contrast, DI failed to decrease during hypoxia (+7.1 +/- 23%). Two mechanisms for the transient decline of DI in controls were identified: synchronous APD oscillations and transient diminution of the apical-to-basal ventricular APD gradient. CONCLUSIONS: These data demonstrate that inhomogeneity of ventricular repolarization, as measured by DI, changes dynamically with CL shortening. Furthermore, the hypoxic ventricle does not attenuate DI after abrupt CL shortening and thereby lacks a physiological response expected to diminish vulnerability to arrhythmias.

Action Potentials↗
PubMed1991

Whole-cell K+ currents in isolated rabbit corneal epithelial cells.

Membrane currents were recorded from enzymatically isolated cells from basal layers of rabbit corneal epithelium by the whole-cell clamp technique. Pipettes contained 140.4 mM KCl and extracellular K+ concentration was varied. The membrane currents on step voltage changes were rectangular currents with some fluctuations. The fluctuations disappeared near the zero-current potential. The reversal potential in normal Tyrode's solution with 5.4 mM K+ was -57.8 +/- 6.2 mV (mean +/- S.D., n = 10). Increasing [K+]o from 5.4 to 140.4 mM shifted the reversal potentials in the positive direction with a slope of 41.0 mV/decade. Concomitant depolarization of the resting potential was observed on increasing [K+]o. The whole-cell currents were blocked by Cs+ or Ba2+. These suggest that the major current component in the corneal epithelial cells in K+.

Animals↗
PubMed1991

[A trial of molecular diagnosis in Leber's optic neuropathy].

The high frequency of mitochondrial DNA mutation at the nucleotide position (nt) 11,778 was reported in cases of Leber's hereditary optic neuropathy (LHON) after the first report by Wallace et al.. We already reported that it provided a simple diagnostic test by means of PCR (polymerase chain determined the diagnosis of LHON in a case. No nt 11,778 mutation was found in patients with the other optic nerve diseases and in normal controls. This shows the usefulness of molecular diagnosis in LHON. Problems of genetic counselling for patients and female carriers and the possibilities to clarify the cause of LHON were discussed.

DNA↗
PubMed1990

Analysis of a gene cluster for sarcotoxin II, a group of antibacterial proteins of Sarcophaga peregrina.

Sarcotoxin II is a group of antibacterial proteins of Sarcophaga peregrina (flesh fly) with related primary structures. We have cloned three genes in this family. These genes formed a tandem array with about 2-kb intervals, and one of them was present in the opposite strand. The putative amino acid sequences of the proteins encoded by these genes were very similar except for a deletion in one of them. All of the genes were found to be activated transiently in the same way when the larval body wall was injured, suggesting that the encoded proteins are acute-phase-responsive proteins for protecting the insect from bacterial infection.

Amino Acid Sequence↗
PubMed1990

[Quantitative analysis of collagen fiber in keratoconus].

In order to identify the direct pathogenic factors involved in the stromal thinning of keratoconus, quantitative analysis of keratocytes, collagen fibers and collagen lamellae in keratoconus cornea was performed histologically by light and electron microscopy. Both normal and keratoconus corneas showed a similar cell density of keratocytes in the central stroma, therefore the total number of keratocytes in keratoconus cornea might be smaller than that of controls, because of the thinning of stroma in the keratoconus. The collagen lamellae in keratoconus corneas showed a significant decrease in number compared with controls. There was a direct relationship between the stromal thickness and number of collagen lamellae. On the other hand, there was no statistical significance between normal and keratoconus corneas in terms of the thickness of collagen lamellae. These results suggest that the thinning of the cornea in keratoconus might occur as the result of a defect of some collagen lamellae due to a disorganization during the process of collagen lamellae formation.

Adolescent↗
PubMed1990

[A Japanese family of Nettleship Falls X-linked ocular albinism].

A family with Nettleship Falls X-linked ocular albinism (NFXOA) was reported. The funduscopic examination revealed that both the male proband case and his maternal male cousin with nystagmus and amblyopia had macular hypoplasia and slightly less pigmented fundus than normal Japanese, and the carrier female (proband's mother) had the characteristic pigmentary mosaicism of the fundus. The slitlamp biomicroscopic examination revealed that the proband case's iris was less pigmented and the carrier female had the normal coloured iris. Translucency was not found in the iris of either the proband case or the carrier female. Hypopigmented maculas were found on the skin of the proband case. Histopathological findings of the cutaneous tissue of both the proband case and the carrier female showed macromelanosomes in the epidermis. The diagnosis of NFXOA is considered to be difficult by ocular clinical signs in the case of Japanese male patients without both characteristic albinotic fundus and the mother's pigmentary mosaicism of the fundus. Macromelanosomes recognized by skin biopsy are helpful for diagnosis.

Adult↗
PubMed1990

[Ocular symptoms in mitochondrial myopathy].

The corneal endothelial cells in 6 cases of mitochondrial myopathies were examined by specular microscope, and electron microscopic studies of the cornea were made in one autopsy case. The cornea was clear and the thickness was within the normal range. The endothelial cell mean size was larger in 3 out of 10 eyes than among controls and the variance of endothelial cell size was larger in all of 10 eyes than among controls. The difference was found to be statistically significant. Electron microscopical findings of the cornea revealed mitochondrial abnormalities. Inclusions were observed in the stromal keratocyte.

Adult↗
PubMed1989

[Effects of periodontopathic bacterial components on phagocytic activity of rat peritoneal macrophages. Examination using ELISA].

This study examined the phagocytic activity of rat peritoneal resident macrophages to determine the movement of macrophages in local inflammation in periodontal disease. We studied phagocytic activity by enzymelinked immunosorbent assay (ELISA) and used the peroxidase-anti-peroxidase soluble complex (PAP; soluble immune complex) as a marker in. We also determined the basic conditions of this examination and studied the effects of bacterial components and the supernatants of sonicated periodontopathic bacterias. We obtained the number of applied macrophages, the concentration of PAP to use and the incubation time. The phagocytic activity of macrophages was enhanced significantly by the bacterial components lipopolysaccharide (LPS) and muramyldipeptide (MDP). Phagocytic activity was also enhanced by the addition of the supernatant of sonicated Bacteroides gingivalis at 40 micrograms/ml (concentration of protein) and significantly suppressed at 320 micrograms/ml. Moreover, activity was significantly enhanced by the supernatant of sonicated Capnocytophaga suputigena at 40 micrograms/ml and 160 micrograms/ml, and suppressed by the supernatant of Fusobacterium nucleatum at a low concentration of protein (5 micrograms/ml). These results suggested that LPS of gram-negative bacteria's endotoxicity and MDP on pivotal structure of peptidoglycans, which are bacterial cell surface components, exerted an effect on phagocytic activity. It was further indicated that the phagocytic activity of macrophages varied with the effects of each periodontopathic bacteria.

Animals↗
PubMed1989

[Clinical application of sintered bone (II). Effects of collagen coating on implant materials in vitro].

In vitro studies with osteoblast-like cells, revealed that in addition to preventing the immediate outflow and promoting stabilization of implant materials, these cells have the additional effect of promoting the mending and early calcification by coating the materials with collagen. The materials used for the experiment were minute hydroxyapatite, beta-tricalcium phosphate and bovine sintered bone. To these, atelocollagen which is solble in pepsin extracted from calf corium and crosslinked by using ultraviolet rays was added. We observed the cells very closely after these materials were added to alpha-modified eagle's medium containing 10 mM beta-glycero phosphate, 10% fetal bovine serum and osteoblast-like cells and the cultures incubated at 37 degrees C and 5% CO2. After 14 and 21 days, cells were fixed and stained with Alizarin Red S and Von Kossa stains to measure calcification. As a result of the collagen coating, positive areas appeared and, compared to the control improvement of the early mending was apparent. The results suggest that by coating the materials with collagen, the osteoblast-like cells show better mending and early calcification.

Animals↗
PubMed1989

[Corneal crystalline deposits in multiple myeloma].

Two cases of multiple myeloma with corneal opacity were reported. Their chief complaint was blurred vision, and general check-up performed prior to cataract operation revealed that one case had multiple myeloma of IgG-kappa and another, of IgG-lambda type. Two corneal buttons obtained at the time of lamellar keratoplasty operations in the IgG-kappa case were studied immunohistopathologically as well as electron microscopically. Corneal opacity observed with a slit lamp was localized at the anterior stroma of both corneas. Immunohistological studies revealed that the deposit was IgG-kappa chain. Transmission electron microscopy disclosed electron-dense extracellular deposits that exhibited a honeycomb appearance and parallel linear structures with a periodicity of 12nm.

Aged↗
PubMed1989

The effect on the cornea of alpha cyclodextrin vehicle for cyclosporin eye drops.

We tested four different combinations of alpha-CD and CYA: 0.075% and 80 mg/mL alpha-CD, 0.025% CYA and 40 mg/mL alpha-CD, 0.009% CYA and 20 mg/mL alpha-CD, and 0.003% CYA and 10 mg/mL alpha-CD. We found that 0.025% CYA (alpha-CD[40 mg/mL]) resulted in the least corneal toxicity and penetrated in the cornea 5 to 10 times more than did lipophilic vehicle with CYA.

Administration, Topical↗
PubMed1989

[Schnyder crystalline dystrophy].

Three cases of Schnyder Crystalline dystrophy of the cornea were reported, one of them was in the incipient stage, the other was in the advanced stage. Both eyes of one advanced case underwent lamellar keratoplasty. Corneal buttons were examined histopathologically. A positive staining was found in the stroma by oil red dye. Electron microscopically , multiple small lucent vacuoles and rod-like structures were present in the stroma. Elevation of total cholesterol and phosphatide serum was found in two out of three cases.

Adolescent↗