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Biomedical subjects

T Otori

Publications and source records attributed to T Otori.

At least 55 records · Page 3Linked to original sources
PubMed1988

The network structure of corneal fibroblasts in the rat as revealed by scanning electron microscopy.

The overall morphology of corneal fibroblasts in the rat was examined by scanning electron microscopy after removal of stromal connective tissue elements by tryptic digestion and HCl hydrolysis. Fibroblasts thus exposed were flattened and stellate cells with a diameter of about 10 micron and had a number of ramified cytoplasmic processes. The processes of neighboring fibroblasts contacted with each other to form an extensive and continuous network structure parallel to the plane of collagenous lamellae. The cellular network appears to constitute an integrated system which may be involved in the synchronized regulation of the metabolic and physiologic homeostasis for the maintenance of corneal transparency.

Animals↗
PubMed1987

Electron-microscopic studies on the presence of gap junctions between corneal fibroblasts in rabbits.

Corneal fibroblasts, major cellular components of the corneal stroma, are loosely arrayed between collagen lamellae. They play an important role in the metabolic and physiological homeostasis mechanisms by which the cornea is kept transparent. This paper deals with the demonstration of the gap junctions between the corneal fibroblasts of rabbits by transmission electron microscopy of thin sections and of freeze-fracture specimens. Under the transmission electron microscope, the corneal fibroblasts are seen between the lamellae of collagen fibers of the corneal stroma. Their long cytoplasmic processes are in contact with those of neighboring fibroblasts. Typical gap junctions are found between these cytoplasmic processes. In the freeze-fracture images, intramembrane particles with a diameter of 10.3 nm form polygonal aggregates on P faces. These findings suggest that corneal fibroblasts, coupled with each other, might function synchronously through gap junctions responsible for metabolic activities essential for the maintenance of corneal transparency.

Animals↗
PubMed1987

Uptake of india ink particles and latex beads by corneal fibroblasts.

The fate of India ink particles and polystyrene latex beads injected into the corneal stroma of rabbits was studied by the naked eye, light microscopy, and electron microscopy. All the injected ink particles or latex beads were unchanged in shape, size, and number for at least 6 months. India ink particles and latex beads were endocytosed by the corneal fibroblasts within 3-4 days after injection. Numerous ink particles were packed into vacuoles, 0.5-10 micron in diameter, which occupy a large volume of the cytoplasm of the cell body and processes of fibroblasts in and near the injected area. Each latex bead, 0.72 micron in diameter, is usually enclosed in one vesicle, and a large number of vesicles are distributed throughout the cytoplasm. In corneal tissue removed 10 min after injection of India ink and cultured for 3 or 7 days, uptake of many ink particles by the fibroblasts was seen. By this experiment, the contribution of the blood-derived cells was completely excluded, and it is more distinctly shown that the corneal fibroblast has a strong endocytotic activity. The uptake and long-term storage of ink particles and latex beads by the corneal fibroblast are reactions that protect the organ without inflammation from the injury and harm by non-toxic foreign materials.

Animals↗
PubMed1987

Spontaneous persistent epithelial defects after cataract surgery.

The natural course of corneal epithelial erosions was studied retrospectively in patients who had undergone cataract extraction. Postsurgical epithelial defects occurred in 41 of 796 eyes (5.2%). No difference was noted in the incidence of corneal epithelial defects in eyes after intracapsular and extracapsular cataract extraction. Of the 41 eyes with postsurgical corneal erosion, 26 (63.4%) showed corneal epithelial defects by the fourth postoperative day. Two types of healing patterns were noticed: rapid healing, in which there was complete epithelial resurfacing within 4 days after the onset of corneal erosion, and prolonged healing, in which the period for complete epithelial resurfacing ranged from 6 days to 34 days. Since fibronectin has been reported to facilitate corneal epithelial migration and adhesion, we administered autologous fibronectin eyedrops in five cases in which corneal epithelial erosion developed after cataract surgery and epithelial defects persisted more than 7 days (except case 2). In all cases receiving fibronectin treatment, complete epithelial resurfacing occurred. In four of five eyes, fibronectin eye drops were effective in epithelial resurfacing within 3-9 days; in one eye, complete epithelial resurfacing took 23 days. The present results indicate that there are two types of epithelial erosion and that fibronectin eye drops might be one of the possible therapeutic approaches for the treatment of persistent epithelial defects. The weak adhesion of epithelial cells underlying basement membrane may be one of the causes of persistent epithelial defects after cataract surgery.

Adult↗
PubMed1987

Fibronectin enhances the phagocytic activity of cultured rabbit keratocytes.

To understand corneal stromal wound healing, we investigated the effect of fibronectin (FN) on the phagocytic activity of rabbit corneal keratocytes. The phagocytic activity was measured under a dark-field microscope using polystyrene latex beads coated with either FN, bovine serum albumin, or both. The percentage of phagocytosing cells increased with incubation time. The phagocytic activity was significantly enhanced in a dose-dependent manner by coating beads with FN. Transmission electron microscopic observation demonstrated that latex beads were internalized into the cytoplasm and were surrounded by limiting membranes. These findings indicate that cultured keratocytes have phagocytic activity and that FN shows opsonic effects on the phagocytic activity, suggesting that FN in the injured corneal stroma may play a role in stromal wound repair by opsonic effects.

Animals↗
PubMed1980

Ethambutol neurophathy: clinical and electroneuromyographic studies.

Clinical features including changes in the peripheral nerve conduction were analzyed in 10 cases with ethambutol neuropathy. There were abnormalities in the visual field in seven and optic atrophy in five of 10 cases. Seven of 10 cases complained of numbness in the lower limbs. The age of onset and dose of ethambutol the patients continue to take after the occurrence of visual impairment were found to be important in determining the severity of neurological symptoms. A functional disturbance was more conspicuous in ethambutol neuropathy, particularly in the sensory system than in the motor system so far as the peripheral nerve conduction was serially examined. Some cases still had serious optic disturbances even about seven years after the onset of the disease and the presence of irreversible lesions was suspected.

Adolescent↗