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Biomedical subjects

R Okamura

Publications and source records attributed to R Okamura.

At least 37 records · Page 2Linked to original sources
PubMed1992

A new bioabsorbable material for rat vascular cuff anatomosis: establishment for the long-term orthotopic liver transplantation model.

Rat vascular anastomosis was performed using a newly synthesized bioabsorbable material (LA-GA copolymer) cuffs and the ordinary polyethylene cuffs. The LA-GA copolymer cuff which anastomosed the portal vein and the inferior vena cava were patent and developed no collateral veins even after 6 months, keeping the transplanted liver normal. By contrast, the polyethylene cuff anastomosed portal vein was completely occluded and the collateral veins were highly developed, with the transplanted liver showing the fatty degeneration of hepatocytes and numerous regenerative nodules. It is concluded that the LA-GA copolymer cuff is a suitable material for the short and long term study of rat orthotopic liver transplantation.

Absorption↗
PubMed1992

[A case of retroperitoneal ganglioneuroma].

A 50-year-old woman was admitted under a diagnosis of abdominal tumor. Ultrasonography and CT scanning were performed, and a right retroperitoneal tumor was detected. Absolute curative resection was performed. The resected tumor was 13.5 x 11.5 x 9.0 cm, and histologically diagnosed as ganglioneuroma. To our knowledge, 99 cases have been reported in Japan. During a twelve-month follow-up period, the postoperative course was uneventful and no recurrence had been noted.

Female↗
PubMed1992

Ocular microangiopathy in familial amyloidotic polyneuropathy, type I.

To obtain precise information on ophthalmological manifestations in patients with familial amyloidotic polyneuropathy (FAP), we performed ophthalmological and histopathological studies on 18 FAP patients and 6 asymptomatic individuals with a mutant transthyretin (TTR) gene. The incidence of vascular abnormalities of the conjunctiva and retina was surprisingly high in FAP patients. Abnormal conjunctival vessels were found mainly in the limbal area of FAP patients, but not in asymptomatic individuals with a mutant TTR gene. Conjunctival biopsy of 5 FAP patients and autopsy of another 2 FAP patients revealed that a significant amyloid deposit could be recognized in the superficial substantia propria of the conjunctiva and wall and perivascular area of the conjunctival vessels in all cases, a finding that is of diagnostic value. As for the retinal vessels, an abnormal arteriovenous ratio (A/V ratio), tortuous retinal vessels, cotton wool exudates and retinal hemorrhages were found in FAP patients. However, histopathological analysis of the retina in two autopsied cases revealed only a trace amount of amyloid deposit around the retinal vessels. Ophthalmological examination of three patients with pandysautonomia revealed that the appearance of both the conjunctival and retinal vessels of these patients was similar to that in FAP patients. These results indicate that in FAP patients ocular microangiopathy may be related to autonomic dysfunction as well as amyloid deposit.

Adolescent↗
PubMed1992

Low-temperature fluorometric technique for evaluating the viability of rat liver grafts after simple cold storage.

Time-dependent changes in the viability of rat liver graft during cold preservation with Euro-Collins solution were evaluated with NADH fluorometry. Correlation between the fluorometric analysis, 1-week survival rate after liver transplantation, and mitochondrial ATP synthesis activity in the early phase after transplantation was studied. Fluorometric study: Rat livers were preserved at 0 degree-4 degrees C for 0-48 h in Euro-Collins solution and then reperfused for 15 min with oxygenated Krebs-Henseleit solution at 4 degrees C. The amplitude (R x A) between the oxidized and the reduced steady-state NADH fluorometric trace and the velocity (R x V) of the trace were determined to evaluate the mitochondrial respiratory chain. The R x A and R x V remained at levels higher than 90% of control after 6-h preservation, while the R x A of the 9-h preservation group and the R x V of the 12-h preservation group decreased significantly compared with those of the control and the 6-h preservation group. Survival study: a 100% survival rate after transplantation was achieved in the 6-h preservation group, whereas the rates were 18.8% and 0% in the 9- and 12-h preservation groups respectively. These survival rates correlated closely with the time-dependent decrease of the fluorometric parameters. Study of mitochondrial phosphorylative activity and energy charge 3 h after transplantation: With fresh grafts, the decrease in hepatic energy charge after transplantation was reduced to 0.79 from the control value of 0.86 by a 30% increase in mitochondrial ATP synthesis ability.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗
PubMed1992

Hydrocephalus, corneal opacities, deafness, valvular heart disease, deformed toes and leptomeningeal fibrous thickening in adult siblings: a new syndrome associated with beta-glucocerebrosidase deficiency and a mosaic population of storage cells.

We describe three adult siblings with communicating hydrocephalus, corneal opacities, deafness, valvular heart disease, and deformed toes associated with glucosylceramide (glc-cer)-beta-glucosidase deficiency. The common manifestations of Gaucher disease were not evident. Supranuclear gaze palsies characteristic of type 3 were noted from early childhood, although the major signs were undeveloped until early adult life. Autopsy disclosed thickened leptomeninges with perivascular fibrosis, non-rheumatic calcified aortic and mitral stenosis with marked fibrosis, and mild infiltration of Gaucher cells in the reticuloendothelial organs. In contrast to the slight accumulation of glc-cer in the liver and spleen, the activity of glc-cer-beta-glucosidase was markedly decreased in the tissues, as much as in a patient with type 2 Gaucher disease. Common mutations were not found in the glucocerebrosidase gene.

Adult↗
PubMed1992

Nonfamilial and unusual cases of Leber's hereditary optic neuropathy identified by mitochondrial DNA analysis.

Peripheral blood mitochondrial DNA (mtDNA) samples from 11 patients with acute optic neuritis or insidious optic atrophy were examined for the mutation at nt 11778 and nt 3460 in polymerase chain reaction products. The mtDNA mutation at nt 11778 was evident in 8 cases, which led to a definite diagnosis of Leber's hereditary optic neuropathy (LHON); 4 of the cases were familial and the remaining 4 cases were nonfamilial. None of the 11 patients showed the nt 3460 mutation. The symptoms and signs were variable among the LHON cases with nt 11778 mutation. Assessment of mtDNA provides a useful diagnostic aid for clinically undefined, seemingly nonfamilial or atypical cases of Leber's hereditary optic neuropathy, particularly in bilateral, insidious optic nerve disease in early childhood.

Acute Disease↗
PubMed1991

Inhibitory effects of ovomacroglobulin on bacterial keratitis in rabbits.

We studied the inhibitory effects of chicken egg-white ovomacroglobulin (ovoM) on keratitis induced by 56,000-Da protease (56 KP) of Serratia marcescens and by elastase (PE) and alkaline protease (PAP) of Pseudomonas aeruginosa. The effects of ovoM on the serratial and pseudomonal keratitis in rabbits were also elucidated. In one model, four drops of 56 KP, PE, or PAP (1 mg/ml) were applied to wounded corneas of eight eyes. Thereafter, 80 microliters ovoM (10 mg/ml) was dropped into four eyes and 0.01 M phosphate-buffed 0.15 M saline (pH 7.4) into the other eyes as a control. The other in vivo test system involved intrastromal injection of S. marcescens or P. aeruginosa, by which each sample (10(5)-10(7) colony-forming units) mixed with ovoM was injected into one cornea and the other cornea received organisms without ovoM. OvoM completely inhibited the activity of these bacterial proteases in vitro and reduced corneal destruction in experimental keratitis in rabbits. In addition, greatly accelerated wound healing was observed.

Administration, Topical↗
PubMed1991

Effects of protease inhibitors on growth of Serratia marcescens and Pseudomonas aeruginosa.

The growth inhibitory effects of chicken egg white ovomacroglobulin (ovoM) on Serratia marcescens and Pseudomonas aeruginosa were studied. The growth of protease-producing strains was greater than that of the strains producing little protease, and was inhibited in a dose-dependent manner by ovoM, a potent protease inhibitor. Dose-dependent enhancement of growth of strains of S. marcescens and P. aeruginosa that produce little protease was observed with the medium treated with proteases. These results indicate that extracellular proteases produced by the organisms augment their growth and that inhibition of the proteases results in suppression of growth.

Gelatin↗
PubMed1991

Leiomyosarcoma of the skin with generalized metastases: electron microscopic and immunohistochemical study.

A 62-year-old woman with numerous (more than 50) tumors between 25 and 75 mm in diameter disseminated over most of her body surface is reported. Biopsied tissue specimens demonstrated that the tumors consisted mainly of spindle-shaped cells with nuclear pleomorphisms and relatively high mitotic rates. They were irregularly arranged; they sometimes mimicked storiform- and palisading-patterns. Immunohistochemistry revealed that the tumor cells were positive for muscle-specific actin, desmin, and myosin, but negative for S-100 protein. Electron microscopy confirmed myofilaments and dense patches in the cytoplasm. The metastatic potential of such leiomyosarcoma of the skin is indicated.

Cytoskeletal Proteins↗
PubMed1991

Suppression of rat deoxycorticosterone-salt hypertension by kallikrein-kinin system.

Brown Norway kininogen-deficient rats had very low levels of plasma kininogens and lower levels of plasma prekallikrein, compared with those of normal rats of the same strain. Systolic blood pressure, determined by the tail-cuff method, of 5-week-old kininogen-deficient rats (106 +/- 0.4 mm Hg, n = 7) and the rate of systolic blood pressure increase with age were not different from those in normal rats. Weekly injections of deoxycorticosterone acetate (5 mg/kg s.c.) with 1% sodium chloride solution in drinking water after uninephrectomy at 7 weeks of age caused a gradual increase in the blood pressure of normal rats, reaching a plateau at 18 weeks of age, whereas that of deficient rats rose rapidly to 158 +/- 6 mm Hg 2 weeks after the start of treatment and continued to increase slightly, becoming significantly higher than normal rats at 8, 9, 10, 11, and 12 weeks of age (p less than 0.05 or 0.01). The levels of urinary prokallikrein and active kallikrein were slightly higher in deficient rats before deoxycorticosterone acetate-salt treatment but were not significantly increased after this treatment, whereas these levels in normal rats were increased 3.6- and 4.7-fold by this treatment. Urinary free kinin, collected from the ureter in untreated deficient rats, was below the detection limit. The plasma level of low molecular weight kininogen, the substrate of glandular kallikrein, was decreased in normal rats during the treatment. Continuous subcutaneous injection of aprotinin by an osmotic pump to normal rats induced significant increase in blood pressure. These results indicate that glandular kallikrein may play a suppressive role in deoxycorticosterone acetate-salt hypertension.

Animals↗
PubMed1991

[A case of cystic mediastinal lymphangioma].

A 41-year-old man was admitted to our hospital because of an abnormal shadow which was pointed out on the chest x-ray film in mass screening. The operation was performed through left thoracotomy. The cyst was unilobular and 43 x 36 x 36 mm in size, located in the middle position of upper mediastinum. This localization has not been reported among 46 cases of the mediastinal lymphangiomas in Japan. Preoperative diagnosis is very difficult since roentogenographic feature is few for ruling out other mediastinal tumors. The complete resection of the cyst is recommended.

Adult↗
PubMed1991

Inhibition in rat of development of in utero galactose-induced cataract by an aldose reductase inhibitor--a light microscopic study.

Aldose reductase inhibitors (ARIs) have been known to be effective in preventing galactose cataract by blocking the polyol pathway. Because the rat congenital galactose cataract is also induced by accumulated polyol, the effect of an ARI in the induction of congenital galactose cataract was investigated. Pregnant rats were placed on a 30% galactose diet. On fetal day 16, 17, 18 or 20, the fetal lenses were examined by light microscope. Lenses from newborn rats with mothers fed galactose diet until gestational day 16, 17, 18 or 20 and then given a galactose diet containing ARI were also examined. The fetal lenses obtained from galactose-fed mother rats on day 16 of gestation were morphologically similar to those of controls. On day 17, the experimental lenses displayed vacuolated areas. The lenses of newborn rats with mothers given an ARI diet after gestational day 16 showed no morphological changes, while a few small vacuoles were observed in the lens of rats with mothers given the ARI diet after day 17, 18 or 20 of gestation. ARI inhibited the rat congenital galactose cataract even when the drug was given to the mother rat during a late stage of pregnancy.

Aldehyde Reductase↗
PubMed1991

Spreading of Serratia marcescens in experimental keratitis and growth suppression by chicken egg white ovomacroglobulin.

We studied the inhibitory effects of chicken egg white ovomacroglobulin, a broad-spectrum protease inhibitor, and a synthetic protease inhibitory peptide, Bz-GFR-O-mercaptoanilide, on the growth of two strains of Serratia marcescens in a synthetic medium. The growth of the virulent protease-producing strain, S. marcescens kums 3958 (kums 3958), was more rapid than that of the strain producing minimal protease, S. marcescens kums NA (kums NA), and kums 3958 was inhibited in a dose-dependent manner by ovomacroglobulin. The synthetic inhibitor also inhibited the growth of kums 3958 weakly. Dose-dependent enhancement of growth of kums NA was observed in the medium treated with the serratial 56 kilo Dalton protease. By immunohistochemical methods using an antibody to the bacteria, the spreading of kums 3958 was also studied in corneal tissue in experimental keratitis of the guinea pig. In vivo, kums 3958 grew locally, and then spread widely by destroying stromal tissue 7-8 hours after intrastromal injection of the organisms (3 x 10(4) colony-forming units). On the other hand, when kums 3958 mixed with ovomacroglobulin was injected into the cornea, the organisms remained locally in the corneal stroma which showed a lower grade of damage. These results indicate that proteases secreted from S. marcescens destroyed corneal stroma, yielding the organisms enough space for further spreading.

Anilides↗
PubMed1990

Type VI collagen in healing rabbit corneal wounds.

A type-specific monoclonal antibody was used to examine the localization of type VI collagen in healing full-thickness corneal wounds (3 mm in diameter) in rabbits. By immunofluorescence, in 1-week-old wounds, type VI collagen was found only at the wound periphery. Subsequently, type VI collagen showed a rapid increase throughout the wounded area. In 3-week-old wounds, type VI collagen immunofluorescence had a laminar pattern as seen in normal corneal stroma, although it was irregular in arrangement. By electron-microscopic immunohistochemistry, type VI collagen was found in the pericellular region of fibroblastic cells possibly derived from keratocytes. These results suggest that type VI collagen might originate from the fibroblastic cells and play an important role in the regeneration of the corneal lamellar structure.

Animals↗
PubMed1990

Inhibition of corneal inflammation by an acylated superoxide dismutase derivative.

Superoxide radicals and their metabolite(s) have been postulated to play an important role in the pathogenesis of inflammation. Hence, superoxide dismutase (SOD) has been used to reduce tissue injury caused by reactive oxygens. However, protection of the cornea and other ocular tissues from oxygen toxicity could not be achieved by administering SOD presumably due to its unfavorable in vivo behavior. To scavenge superoxide radicals on the outer surface of corneal epithelial cells, the authors synthesized an acylated SOD derivative (AC-SOD) by linking capric acid. When instilled into rabbit eyes, a significant amount of AC-SOD remained bound to the corneal surface for a fairly long time. Intracorneal injection of lipopolysaccharide (LPS) triggered infiltration of polymorphonuclear leukocytes (PMNs) to the cornea and induced severe keratitis. Topical administration of AC-SOD to the LPS-treated cornea markedly inhibited the infiltration of PMNs and suppressed the occurrence of keratitis. Under identical conditions, topically administered SOD was rapidly removed by tears and, hence, did not inhibit LPS-induced keratitis. When the number of PMNs in the systemic circulation was reduced by intravenous administration of hydroxyurea, LPS-induced keratitis was inhibited markedly. These results indicate that superoxide radicals and circulating PMNs might play a critical role in LPS-induced keratitis.

Acylation↗