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Biomedical subjects

Y Segawa

Publications and source records attributed to Y Segawa.

At least 145 records · Page 8Linked to original sources
PubMed1989

[Experimental study on the effects of a replacement of the vitreous body with perfluorotributylamine on the rabbit eye].

The effects of replacement of the vitreous body with perfluorotributylamine on albino rabbit eyes were studied. Twenty eight eyes were divided into three groups. In the first group (n = 14), which was used as a control, only vitrectomy was performed. In the second group (n = 6), the vitreous was temporarily substituted with perfluorotributylamine after the vitrectomy. One hour after the operation, the injected perfluorotributylamine was again replaced with a balanced salt solution (SM-A2). In the third group (n = 8), the injected perfluorotributylamine was left in the eye until the time of enucleation. The eyes were evaluated both electrophysiologically and histopathologically, at predetermined time intervals ranging from one to form one to four weeks after operation. All the eyes in the second group did not show any histopathological changes until four weeks after the operation. The ERGs obtained from these eyes exhibited dominant a- and b-waves similar to those of the control group at all intervals after operation. However, the eyes in the third group showed progressive deterioration with elapsed of time. At the two weeks after operation, b-wave amplitudes moderately decreased in two eyes. These eyes showed an initial slight degeneration in the outer segment layer. At four weeks after the operation, the a- and b-waves further decreased in amplitude with a significantly prolonged peak latency. The outer segments were severely damaged, and the histopathological changes extended to the inner segment layer as well as the RPE layer.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Importance of cell surface marker to the prognosis of non-Hodgkin's lymphoma.

We studied the correlation between the cell surface markers and prognosis of non-Hodgkin's lymphoma (NHL) patients treated in the Shikoku Cancer Center Hospital from 1980 to 1986. Thirty-one cases were selected on the basis of having a lymphnode as a primary lesion, having been immunophenotyped before chemotherapy, being in the intermediate histologic grade and being in stage II, III or IV. Thirteen cases of the T-cell type (T-lymphomas) and 18 cases of the B-cell type (B-lymphoma) were identified. The complete remission rate was 54% among T-lymphoma patients and 78% among B-lymphoma patients. The median length of survival was 12+ months in T-lymphoma and 26+ months in B-lymphoma. The survival rate of T-lymphoma patients was significantly lower than that of B-lymphoma patients. The importance of making surface marker studies was reappraised in our study.

Antigens, Surface↗
PubMed1987

Liquid chromatographic assay of the relative activities of serum pancreatic and salivary alpha-amylase using reductively pyridylaminated maltopentaose as a fluorescent substrate.

A method for the high-performance liquid chromatographic assay of the relative activities of serum pancreatic and salivary alpha-amylase has been developed, using maltopentaose reductively aminated with 2-aminopyridine as a fluorescent substrate. Both enzymes showed similar modes of action, cleaving the second and the third (from the non-reducing terminal) interglycosidic linkages of this substrate. However, the relative ease of cleavage of these two sites by the pancreatic enzyme was significantly different from that by the salivary enzyme. Therefore, determination of the molar ratio of the cleavage products by HPLC could lead to estimation of the activity ratio of these enzymes. The optimum chromatographic conditions for HPLC were as follows: column, LiChrosorb RP-18 (Merck, 7 microns, 250 X 4 mm I.D.); column temperature, ambient; eluent, 0.01% orthophosphoric acid-acetonitrile (4:1, v/v) containing 2.4 mM sodium laurylsulphate; flow-rate, 1.0 ml/min; wavelengths for fluorimetric detection, 320 nm (excitation)/400 nm (emission). The problem of interference by serum alpha-glucosidase was solved by specific inhibition with tris (hydroxymethyl) aminomethane and erythritol. The data obtained by the proposed method correlated well with those produced by the conventional method based on electrophoresis.

Aminopyridines↗
PubMed1987

[Primary malignant fibrous histiocytoma of the breast, report of a case].

Although malignant fibrous histiocytoma (MFH) is the most common soft tissue sarcoma of adult, it rarely arises in the breast tissue. Only seven cases have been previously reported in Japan. One case of the MFH of the mammary gland is presented in this paper. A 39 year old woman, who had received no radiation, was referred to our hospital due to a painful right breast lump. Excisional biopsy revealed yellowish white soft tumor with an obscured margin. Histological, tumor was composed of spindle shaped cells of a storiform pattern, which was diagnosed as MFH of the breast. Radical mastectomy (Br + Mj + Ax) was added to this patient. The tumor invaded to the fat tissue without metastasis to the axillary lymph nodes. We performed the post-operative adjuvant chemotherapy of Adriamycin. She made an uneventful recovery and is now free of disease eleven months postoperatively.

Adult↗
PubMed1986

Suppression of the hyperosmolarity response after cataract surgery.

The hyperosmolarity response was recorded with the electrooculogram in the dark before and after cataract extraction, to investigate a possible disorder in the retinal pigment epithelium after cataract extraction. The hyperosmolarity response was suppressed one week after surgery, especially after intracapsular extraction. The response recovered up to the preoperative level in most cases one or two months after surgery. These findings indicate reversible functional disorders of the pigment epithelium after cataract extraction, particularly intracapsular. This dysfunction can be revealed by the hyperosmolarity response. This response is clinically useful for diagnosis of pigment epitheliopathy after cataract extraction.

Adult↗
PubMed1986

Acetazolamide-induced changes of the membrane potentials of the retinal pigment epithelial cell.

Acetazolamide-induced changes of the apical (Vap) and basal (Vba) membrane potentials of the retinal pigment epithelial cell were studied in an in-vitro retinal pigment epithelium (RPE)-choroid of the frog. Both Vap and Vba were hyperpolarized by acetazolamide placed on either the apical or basal side of the RPE. In all cases, acetazolamide on the apical side hyperpolarized Vba more than Vap and decreased the transepithelial potential (TEP) across the RPE. In most cases, acetazolamide on the basal side hyperpolarized both Vap and Vba to almost equal degrees and hardly changed the TEP. We conclude that the Diamox response (a decrease of the ocular standing potential induced by an intravenous sodium acetazolamide) may be triggered by effects of acetazolamide on the apical side of the RPE and generated mainly by a hyperpolarization of the basal membrane of the RPE cell.

Acetazolamide↗
PubMed1985

PaO2 change during progressive pulmonary edema in dogs.

We observed the changes of PaO2, pulmonary shunt (Qsp/Qt), effective compliance, and direct lung impedance after induction of hydrostatic pulmonary edema in five mongrel dogs. Edema was induced by elevating left atrial pressure in a stepwise manner while the dogs were ventilated with continuous positive pressure. Corresponding morphologic changes in the lung were examined by light and electron microscopy. PaO2 changed little or slightly until mean left atrial pressure reached 40 to 60 mm Hg. PaO2 then rapidly decreased from 411 +/- 61 to 89 +/- 19 torr, accompanied by an increase in Qsp/Qt from 33 +/- 6% to 57 +/- 14%. Effective compliance decreased gradually and direct lung impedance decreased rather steeply at first and then gradually. Lung specimens taken before the abrupt fall of PaO2 revealed froth on the cut surface, indicating that alveolar pulmonary edema preceded the PaO2 decrease. Electron microscopy showed widening and splitting of the thin portion of the alveolar-capillary interstitium when PaO2 fell abruptly. This widening of the thin portion may have been one of the causes of an abrupt PaO2 fall in the dog subjected to volume overload and increased afterload.

Animals↗
PubMed1983

Characterization of protein phosphorylation of the cytosol of AH-66 hepatoma ascites cells.

Endogenous phosphorylation reaction of the cytosol fraction of AH-66 hepatoma ascites cells in vitro was compared with that of normal rat liver. Cytosolic proteins with molecular weights of 125,000, 98,000, and 40,000 of AH-66 cells were heavily phosphorylated in a cyclic adenosine 3':5'-monophosphate-independent manner, but no counterpart was detected in normal liver cytosol. In order to examine whether these phosphoproteins were specifically present in AH-66 cytosol, cyclic adenosine 3':5'-monophosphate-independent protein kinases which phosphorylate these phosphoproteins were partially purified from AH-66 and liver cytosol by successive chromatography. Both kinase preparations were essentially free of endogenous protein substrates and catalyzed the phosphorylation of exogenous substrates, such as casein and phosvitin, but not histone and protamine. Both kinases markedly catalyzed the phosphorylation of the Mr 125,000, 98,000, and 40,000 proteins in AH-66 cytosol. The Mr 125,000, 98,000 and 40,000 proteins in liver cytosol were less intensely phosphorylated by the addition of the kinase from AH-66 cytosol. From these results, we conclude that these phosphoproteins are present in both AH-66 cytosol and liver cytosol but are highly concentrated in AH-66 cytosol.

Animals↗
PubMed1982

Analysis of specular photomicrograph with graph pen digitizer. II. Long-term results in cataract surgery.

Bilateral corneal endothelial photomicrographs of 90 cases, who underwent unilateral cataract extraction 5 years ago, were analyzed utilizing a specular microscopy and a graph pen digitizer. Data on surface areas of the corneal endothelium in each group of three different surgical procedures were compared mutually and with those of more recent cases. Mean cell areas in the cases of intracapsular lens extraction, planned extracapsular lens extraction and implantation of intracapsular lens extraction, planned extracapsular lens 604.5 +/- 210.6 micronm2 and 847.4 +/- 289.4 micronm2, respectively. In the IOL cases the mean cell are relatively small when the IOL ws implanted following extracapsular lens extraction. In the 18 cases who had the IOL implanted last year, the mean cell area was significantly smaller than in the previous IOL cases.

Adult↗