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Biomedical subjects

K Masuda

Publications and source records attributed to K Masuda.

At least 649 records · Page 36Linked to original sources
PubMed1985

Progressive cone dystrophy associated with low alpha-L-fucosidase activity in serum and leukocytes.

The enzyme activities of acid phosphatase, beta-glucuronidase, N-acetyl-beta-D-glucosaminidase, and alpha-D-mannosidase were not significantly different in patients with myopia, retinal detachment, hereditary macular dystrophy, and unusual progressive cone dystrophy. alpha-L-Fucosidase activity in sera was lower in three patients with myopia and in two patients with unusual progressive cone dystrophy than in most of the others. Leukocytic alpha-L-fucosidase activity was lower in those with unusual progressive cone dystrophy. The two unrelated patients with unusual progressive cone dystrophy had slowly deteriorating visual acuity, color vision, and photopic electroretinographic responses, but ophthalmoscopically normal fundi and noncontributory family histories.

Adolescent↗
PubMed1985

Plasminogen activator activity levels in patients with Behçet's syndrome.

We studied the plasminogen activator levels in plasma samples of 37 patients with Behcet's syndrome. A significant decrease of plasminogen activator activity level was shown by the euglobulin lysis time method, the amidolytic activity level (Testzym method), and the fibrin plate method. Such a decrease may be associated with the severity of Behcet's syndrome.

Behcet Syndrome↗
PubMed1985

Skeletal muscle pathology of mannosidosis in two siblings with spastic paraplegia.

Deficiency of alpha-D-mannosidase was found in two siblings with muscle weakness and spastic paraplegia. A biopsy of the vastus lateralis muscle was studied by light and electron microscopy. Cryostat sections showed mild fiber size variation but no necrosis. Semithin Epon sections revealed many vacuoles in the muscle cells and fibroblasts. Electron microscopy showed that the vacuoles, presumably lysosomal, had a single limiting membrane and contained finely granular or granulo-reticular material, membranous structures, and electron-dense ovoids. The vacuoles were identical with those in lymphocytes and other cells of patients with mannosidosis. Disorganization of sarcomere alignment and widening of intermyofibrillar spaces were also observed. Deficiency of alpha-D-mannosidase is considered to cause slowly progressing degeneration of muscle fibers.

Adult↗
PubMed1985

Endoscopic local injection of hypertonic saline-epinephrine solution to arrest hemorrhage from the upper gastrointestinal tract.

For the purpose of arresting hemorrhage from the upper gastrointestinal tract we developed a method of endoscopic local injection of hypertonic saline-epinephrine solution, consisting of 3.6% or 7.1% sodium chloride with 0.005% epinephrine, which was locally injected around the base of the bleeding vessel under endoscopy. During the period between October 1978 and September 1983, a total of 158 patients underwent treatment for hemostasis by this method. The major causes of bleeding in our study consisted of gastric ulcers (114) and duodenal ulcers (15). The overall effective rate of hemostasis was 98.1%. By applying this method, the rate of emergency operation for patients with bleeding from the upper gastrointestinal tract was significantly reduced from 21.7% (15/69) to 0.8% (1/128).

Adolescent↗
PubMed1985

Pathophysiology and pharmacology of intraocular surgery.

Meticulous studies of the pathophysiology of postoperative eyes are mandatory to find the means of reducing the risks of intraocular surgery. Various methods of examination developed for this purpose are described and their clinical significance discussed. The corneal endothelium shows no proliferative capacity even after injury and great care must be taken to protect this vulnerable cell layer. Drugs may be toxic to the corneal endothelium and their use during surgery must be exercised with caution. The intraocular irrigating solutions must contain calcium and have an appropriate salt composition. Pupillary constriction that occurs during extracapsular cataract extraction is due mainly to prostaglandins synthesized as a result of surgical trauma; this can be prevented by the preoperative use of topical indomethacin. Breakdown of the blood-aqueous barrier after intraocular surgery may also be due to a similar mechanism, and preoperative topical non-steroidal anti-inflammatory agents (indomethacin, flurbiprofen and diclofenac) can prevent this phenomenon, as studied by fluorophotometry. Topical indomethacin also prevents cystoid macular oedema after cataract surgery. Based on the biochemical findings on inflammation after tissue injury, a protocol for the preoperative and postoperative use of corticosteroid and non-steroidal anti-inflammatory agents is proposed for anterior segment surgery.

Anterior Eye Segment↗
PubMed1985

Antitumor activity of a new antibiotic, kazusamycin.

The antitumor activity of a new antibiotic, kazusamycin, against various murine tumors was studied by various treatment schedules. Single, intermittent, and successive injections of the antibiotic were almost equally effective against Ehrlich carcinoma, IMC carcinoma and sarcoma 180 tumor, but successive injections showed more efficacy than the other schedules against Meth A fibrosarcoma and Lewis lung carcinoma. Interestingly, there was no clear dose response for the efficacy of kazusamycin on murine tumors. When HeLa cells were exposed to kazusamycin for 72 hours in vitro, the IC50 value was about 1 ng/ml, however the cytotoxicity of the antibiotic depended on the incubation time.

Animals↗
PubMed1985

Studies on a novel cytocidal antibiotic, trienomycin A. Taxonomy, fermentation, isolation, and physico-chemical and biological characteristics.

A new antibiotic, trienomycin A, has been isolated from the culture broth of Streptomyces sp. No. 83-16. The physico-chemical characteristics of the antibiotic suggested that it belongs to the group of ansamycin antibiotics with a triene moiety in the molecule. The molecular formula of trienomycin A is C36H50N2O7 (MW 622). The antibiotic possesses potent cytocidal activity against HeLa S3 and PLC hepatoma cells at concentrations of 0.1 and 0.01 micrograms/ml (IC50 value) respectively. However, trienomycin A showed no antimicrobial activity against the bacteria, fungi and yeasts examined with the exception of weak activity versus Piricularia oryzae at a concentration of 1,000 micrograms/ml.

Alanine↗
PubMed1985

Two distinctive transforming DNA regions on the canine adenovirus type 1 genome.

By transfecting cloned DNA fragments of canine adenovirus type 1, a novel transforming region of mammalian adenovirus was demonstrated inside the viral genome. Besides the left-end SmaI-D fragment (left 17.2%), an internally located SmaI-E fragment (17.2-28.7%) of canine adenovirus type 1 was found to transform primary rat kidney cells.

Adenoviruses, Canine↗
PubMed1985

Glial cells in culture of preretinal membrane of proliferative vitreoretinopathy.

Nine preretinal membranes surgically obtained from seven patients with proliferative vitreoretinopathy were cultured in Eagle's minimal essential medium or RPMI 1640 medium, both with addition of 10% fetal bovine serum, in order to assess the proliferative capacity of the cells in the membrane. In addition, glial fibrillary acidic protein (GFAP, protein specific for glial cells) was stained in the cultured cells, by the immunoperoxidase method (peroxidase-antiperoxidase technique). Cellular outgrowth consisted of five types of cells; 1) spindle-shaped cells, 2) flat round or polyhedral cells, 3) semilunar cells, 4) stellate cells and 5) polygonal cells in close contact with each other and extending in monolayer. The spindle-shaped cells, the flat round or polyhedral cells, and the semilunar cells were dominant in all cases, and they showed vigorous proliferation and migration. Many of these cells were GFAP-positive, indicating their glial origin. The stellate cells were GFAP-positive, but they were few in number. The polygonal cells were near the explants and were GFAP-negative; they were thought to be derived from the retinal pigment epithelial cells. It was confirmed that the glial cells are the major cellular component of the proliferative preretinal membrane, and that they show vigorous proliferative capacity. It may be concluded that the glial cells play the major role in the formation of the preretinal membrane in proliferative vitreoretinopathy.

Adolescent↗
PubMed1985

Microfilaments in preretinal membrane cells of proliferative vitreoretinopathy.

Electron microscopy was carried out on 8 preretinal membranes surgically obtained from 8 patients after vitrectomy and on primary culture cell outgrowths from 6 preretinal membranes from 6 patients, with particular attention to the presence of actin. Actin was detected as microfilaments in the cultured cells and in the preretinal membrane cells as well, as confirmed by the arrowhead formation seen after heavy meromyosin treatment. The cultured cells and preretinal membranes were glycerinated, and exposed to ATP and Mg2+. With the ATP treatment the cultured cells were observed to contract, and intracellular microfilaments aggregated and formed contraction bands, which are known to be the product of interaction between actin and myosin. Parts of the preretinal membranes were also observed to contract after treatment; in the cells of the preretinal membranes the contraction bands were observed. It was concluded that the intracellular microfilaments in the cells of the preretinal membranes contain actin capable of contraction, thereby inducing contraction of the membrane which exerts traction on the retina.

Actin Cytoskeleton↗
PubMed1985

[Rational dose fractionation schedule 1. Each fractional dose].

The dose per fraction which will produce the maximum therapeutic ratio in clinical radiotherapy is discussed, using the data on the variation of the oxygen enhancement ratio with dose size and the difference in the dose response curves between tumor cell lines and late effects in normal tissues. Isoeffect doses for late injury increased more than that for tumor response with decreasing dose per fraction. When late effects in normal tissues are dose-limiting for radiotherapy, the highest therapeutic ratio (normal tissue tolerance dose/dose for a given probability of local tumor control) would be obtained when the dose/fraction is equal to the flexure dose. Lengthening the interfraction interval to allow complete repair of sublethal injury in the normal tissues responsible for late effects may allow some repopulation of tumor cells. In this case it may be necessary to increase the dose/fraction slightly above the flexure dose.

Cell Survival↗