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Biomedical subjects

A Kurosawa

Publications and source records attributed to A Kurosawa.

At least 37 records · Page 2Linked to original sources
PubMed1990

Visual disturbance in patients with melanocytoma of the optic disk.

Visual disturbance in 11 patients with melanocytoma of the optic disk was analyzed. Goldmann visual field examination showed enlargement of Mariotte's blind spot in 7 of 10 patients (70%) and visual field defect or depression in 7 patients (70%). In 6 of the 7 patients with visual field defect of depression (86%), the portion of visual field damage corresponded with the location of the tumor and retinal nerve fiber bundle defect. In 1 patient, sudden loss of visual acuity occurred, presumably due to anterior ischemic optic neuropathy induced by melanocytoma.

Adult↗
PubMed1989

Long-lasting inhibitory action of caerulein on climbing fiber system in the cerebellum of the rat.

Caerulein caused a marked decrease in levels of guanosine 3',5'-cyclic monophosphate (cGMP) in the cerebellum in rats. This effect was observed to be dose-dependent after the intraperitoneal administration of caerulein for doses over 20 micrograms/kg and lasted for about 4 hr in doses of 100 micrograms/kg. However, in vagotomized rats, caerulein failed to alter the level of cGMP in the cerebellum. Caerulein suppressed harmaline-induced increases in cGMP in the cerebellum for more than 30 hr. In contrast, the increases in levels of cGMP in the cerebellum, induced by treatment with methamphetamine, apomorphine and picrotoxin, were not inhibited by pretreatment with caerulein. These results suggest that the peripheral administration of caerulein can inhibit the activity of climbing fibers for a long period of time in the cerebellum of the rat through the stimulation of the abdominal vagus nerves.

Animals↗
PubMed1989

Effect of a novel thromboxane A2 receptor antagonist, S-145, on collagen-induced ECG changes and thrombocytopenia in rodents.

The effects of S-145, a newly synthesized thromboxane, A2 (TXA2) receptor antagonist, were studied on collagen-induced changes of electrocardiograms (ECG) in rats and thrombocytopenia in rats and mice. Intravenous injection of collagen induced abnormal ECG changes such as elevation or depression of the ST segment, arrhythmia and in severe cases, cardiac arrest. These changes peaked at 3-5 min and lasted for 10 min. S-145 showed remarkable improvement of the ECG changes by both intravenous and oral administration, and the action lasted over 4 hr with 10 mg/kg, p.o. Reference compounds ONO-3708, dazoxiben and aspirin also improved the ECG changes significantly, but ticlopidine was ineffective. S-145 prevented the collagen-induced thrombocytopenia in rats but did not affect the increase in plasma TXB2 levels. S-145 also prevented collagen-induced thrombocytopenia in mice after either intravenous or oral administration in a dose-dependent manner. The efficacy of S-145 was 4-13 times greater than those of the reference compounds, and the duration of action was over 4 hr with 10 mg/kg, p.o. These results indicate that S-145 is a potent, orally, active and long-lasting TXA2 receptor antagonist, which will be promising as a drug for thromboembolism and ischemic heart disease caused by platelet activation.

Administration, Oral↗
PubMed1988

Sporothrix schenckii endophthalmitis in a patient with human immunodeficiency virus infection.

A 30-year-old homosexual man with a positive serologic test for human immunodeficiency virus and a history of successfully treated disseminated cutaneous sporotrichosis developed a granulomatous uveitis that worsened with topical and subconjunctival steroid therapy. Culture of the aqueous aspirate yielded Sporothrix schenckii. The patient was treated with intravenous amphotericin B and intravitreal amphotericin B, kanamycin sulfate, and amikacin sulfate. Subsequent aqueous and vitreous cultures were negative, but the intraocular inflammatory process progressed and ultimately led to enucleation of the eye. Histopathologic examination revealed granulomatous inflammation of the anterior uvea and scattered S schenckii in the anterior and posterior chambers. Electron microscopy demonstrated that most of the organisms had disorganized protoplasm. Although treatment failed to ameliorate the progressive intraocular inflammatory process, the negative cultures and the electron microscopic observations suggest that the treatment was reasonably effective in killing S schenckii within the eye. To our knowledge, this is the first case report of S schenckii endophthalmitis in a patient with human immunodeficiency virus infection.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Monkey trabecular meshwork cells in culture: growth, morphologic, and biochemical characteristics.

We established tissue cultures of trabecular meshwork cells from cynomolgus monkey eyes. The cultures were initiated within 4 h of enucleation on Falcon Primaria flasks. Using medium containing 10% fetal bovine serum and 5% calf serum, trabecular meshwork cells could be grown for up to eight passages without additional growth factors. The growth pattern and cell morphology were distinct from those seen in fibroblastic or endothelial cultures derived from neighboring tissues. Ultrastructurally, our cells showed the characteristics of trabecular meshwork cells, exhibiting prominent basement membranes, intercellular junctions, pinocytotic vesicles, microvillous projections, and branched cell extensions. These cells were grown mostly as monolayers. However, they also appeared to form multi-layered arrays in densely confluent areas when plated at a high density. The extracellular matrix material was surrounded by cells and cell processes, simulating in vivo trabecular beam formation. Radiolabeling experiments demonstrated that our trabecular meshwork cells had the capacity to produce collagen. These results indicated that our cultured cells retain many in vivo characteristics and may be used for various biologic studies of trabecular meshwork.

Animals↗
PubMed1988

Nanophthalmic sclera. Fibronectin studies.

The authors performed fibronectin studies on scleral specimens derived from a patient with nanophthalmos. Immunohistochemical staining with antifibronectin was conducted using both formaldehyde-fixed, paraffin-embedded tissue sections and unfixed tissue-cultured scleral cells. In each case, the nanophthalmic samples exhibited fibronectin staining stronger than that obtained from normal human subjects. Results from an enzyme-linked immunosorbent assay (ELISA) confirmed the histologic findings that, in tissue culture, the patient's scleral cells contained and secreted a higher amount of fibronectin than did the normal control cells. The elevated fibronectin level may be related to the development of nanophthalmos.

Adult↗
PubMed1987

Cultured trabecular-meshwork cells: immunohistochemical and lectin-binding characteristics.

We examined the extracellular matrix formation and lectin-binding properties of cultured trabecular-meshwork cells established from cynomolgus monkey and bovine eyes. Using an avidin-biotin complex method, we found that the extracellular matrix in both the monkey and bovine cultures stained intensely with antibodies to fibronectin, type IV collagen, and laminin. These materials were especially prominent when the cultured monkey trabecular-meshwork cells aggregated in clusters, manifesting their close anatomic relationship to trabecular beams. Cell-surface and intracellular lectin-binding properties were studied using eight biotinylated lectins: concanavalin A (Con A), peanut agglutinin (PNA), Ricinus communis agglutinin (RCA), Dolichos biflorus agglutinin (DBA), soy bean agglutinin (SBA), Phaseolus vulgaris (PHA), wheat germ agglutinin (WGA), and Ulex europaeus agglutinin I (UEA I). Both monkey and bovine trabecular-meshwork cells showed positive cell surface and intracellular binding to Con A, WGA, and PHA. Only moderate cell-surface staining was observed with RCA, and no visible staining occurred with PNA, DBA, SBA, and UEA-1.

Animals↗
PubMed1985

Wedge-shaped retinal nerve fiber layer defects in experimental glaucoma preliminary report.

Many investigators have reported that abnormalities in the retinal nerve fiber layer may be the earliest sign of primary open-angle glaucoma. We attempted to create defects in the retinal nerve fiber layer in experimentally induced glaucoma and to examine their histology. By repeated circumferential argon laser photocoagulation of the trabecular meshwork of normal cynomolgus monkeys, we succeeded in causing a continuous increase in intraocular pressure (IOP). During the course of this experiment, cupping of the optic nerve head, wedge-shaped retinal nerve fiber layer defects, and halo glaucomatosus developed, all of which are defects that are similar to those seen clinically in primary open-angle glaucoma. The IOP required for this fundus change was 25, 35, and 43 mmHg, indicating great individual variation. Histological examination revealed localized degeneration, loss of axon bundles, and diffuse thinning of the nerve fiber layer in the area of these wedge-shaped defects in the retinal nerve fiber layer. These results may indicate that the optic-nerve-damaging mechanism, both localized and generalized, is the same in the cynomolgus monkey and in man.

Animals↗
PubMed1984

[Pharmacological studies of a new sleep-inducer, 1H-1,2,4-triazolyl benzophenone derivative (450191-S) (V). General pharmacological activities].

General pharmacological activities of 450191-S were studied in various species of animals and compared with those of reference benzodiazepines (BDZ). 450191-S at doses of 10 mg/kg slightly decreased (-5 degrees C) the rectal temperature of rabbits. 450191-S decreased respiratory and heart rates in anesthetized cats, but the effects were less than those of diazepam or triazolam. 450191-S increased respiratory and heart rates in conscious dogs, but had no effect on the blood pressure, electrocardiogram and autonomic nervous system in cats and dogs. The drug displayed a slight spasmolytic activity in the small intestine of guinea pigs and a slight inhibitory effect on isolated non-pregnant and pregnant uteri of rats. These effects were less than those of diazepam or nitrazepam. Below doses of 25 mg/kg, 450191-S did not affect urinary volume and electrolyte excretions in rats. It also decreased brain norepinephrine (NE) turnover rates in rats, but decreased NE and dopamine turnover rates in mice. These effects of 450191-S were less than those of nitrazepam. 450191-S was found to be minimally irritating to the ocular mucosa in rabbits and did not irritate the stomach and small intestine in rats. These effects were also compared with those of active metabolites of 450191-S, M-1, M-2, M-A, M-3 and M-4, and the superiority of the mother compound over its metabolites was clarified.

Animals↗
PubMed1982

Ovoid bodies in choroidal neurofibromatosis.

We studied the ultrastructure of the ovoid bodies in choroidal neurofibromatosis. Ovoid bodies consisted of groups of the same kind of elongated cells arranged in lamellar patterns. The elongated cell was characterized by a fragmented circumferential basal lamina, groups of pinocytotic vesicles, a desmosomelike intercellular contact, and intimate contact with axons. These findings suggest that elongated cells are proliferated Schwann's cells and ovoid bodies do not correspond with real sensory nerve end organs; rather, they are enlarged peripheral nerves due to neoplastic hyperplasia of Schwann's cells around axons.

Choroid↗