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Biomedical subjects

M Tamura

Publications and source records attributed to M Tamura.

At least 721 records · Page 40Linked to original sources
PubMed1989

Experimental intraocular lens implantation in the rabbit eye and in the mouse peritoneal space. Part IV: Cell adhesion, fibroblast-like cell, and lymphocytic cluster observed on the implanted lens surface.

Transmission and scanning electron microscopy, Wolter's implant cytology staining, and an immunohistochemical method were used to investigate the process of cell adhesion, the origin of fibroblast-like cells, and the nature of lymphocytic clusters that were observed on intraocular lenses (IOLs) experimentally implanted in the rabbit eye and in the mouse peritoneal space. On the IOL implanted in the mouse peritoneal space, pseudopodia extended during cell adhesion showed morphological variety; on the IOL implanted in the rabbit eye, membranous extensions were seen. Many of the fibroblast-like cells exhibited positive staining for macrophagic antigen, indicating a macrophagic origin. The build-up of lymphocytic clusters, as an indicator of immunologic activity, was frequently observed on IOLs implanted in the mouse peritoneal space, particularly on silicone IOLs. However, such clusters were rarely seen on poly(methyl methacrylate) or silicone IOLs implanted in the rabbit eye, suggesting a much reduced immune response to those materials in the eye chamber.

Animals↗
PubMed1989

Pathogenesis of Hantaan virus in mice.

The virulence of two virus clones (HV cl-1 and HV cl-2) of Hantaan virus, which were plaque-purified on Vero E6 cells, were compared in suckling mice infected by the intraperitoneal or intracerebral route. HV cl-1 increased the mortality of the mice whereas HV cl-2 did not. Furthermore, virus of high titre was isolated from various organs of mice infected with HV cl-1 and high titres were maintained, whereas after infection with HV cl-2, virus was isolated from various organs only in low titre and only temporarily. HV cl-1 strongly induced cell-to-cell fusion, but the cell fusion activity was at a minimum level in cells infected with HV cl-2. However these two clones induced similar titres of antibodies in mice. Cytotoxic T lymphocyte assays against macrophages infected with homologous and heterologous virus showed that cytotoxic T cell activity was induced in mice infected with HV cl-2, but suppressed in mice infected with HV cl-1. These results suggest that an alteration in the cell fusion function and the cytotoxic T cell activity are important in the pathogenesis of Hantaan virus infection in newborn mice.

Animals↗
PubMed1989

Cross-reactive immunity among different serotypes of virus causing haemorrhagic fever with renal syndrome.

Spleen cells primed by Prospect Hill (PH) or Puumala (Pu) virus could cross-react with Hantaan virus (HV) 76-118 strain-infected target cells after in vitro stimulation with HV-infected cells, although anti-PH or anti-Pu immune serum showed no cross-reactive neutralizing (NT) activity to HV without complement. These results and our previous findings with cross-reactive cytotoxic T lymphocytes (CTLs) suggest that some epitopes recognized by CTLs might be common among the hantavirus genus, while the epitopes related to NT activity were mainly specific to each virus of this genus. Next, to evaluate the cross-reactive immunities demonstrated by in vitro study, we investigated the effect of transferring T lymphocytes and sera from BALB/c mice immunized with PH or Pu virus into nude mice before HV inoculation. Transferring T lymphocytes primed by PH or Pu virus reduced HV titres in lungs and spleens of nude mice, corresponding with the results of the in vitro CTL assays. Transferring anti-Pu immune serum also decreased HV titres in nude mice, which seemed to reflect complement-dependent NT activity. Moreover ICR mice previously immunized with PH or Pu virus showed resistance to challenge with a lethal dose of the HV KHF strain, indicating that cross-reactive immunity induced by PH or Pu virus could protect ICR mice against pathogenic HV infection.

Animals↗
PubMed1989

Crystallographic characterization of conformation of 1-aminocyclopropane-1-carboxylic acid residue (Ac3c) in simple derivatives and peptides.

The molecular and crystal structures of the C alpha,alpha-dialkylated alpha-amino acid residue 1-aminocyclopropane-1-carboxylic acid hemihydrate (H2+-Ac3c-O-.1/2 H2O) and nine derivatives and dipeptides have been determined by X-ray diffraction. The derivatives are pBrBz-Ac3c-OH, Piv-Ac3c-OH, Z-Ac3c-OH, the alpha-and beta-forms of t-Boc-Ac3c-OH, Z-Ac3c-OMe, and the 5(4H)-oxazolone from pBrBz-Ac3c-OH; the dipeptides are H-(Ac3c)-OMe and c(Ac3c)2. The values determined for the torsion angles about the N-C alpha (phi) and C alpha-C' (psi) bonds for the single Ac3c residue of Piv-Ac3c-OH, the alpha- and beta-forms of t-Boc-Ac3-OH and Z-Ac3c-OMe, and the C-terminal Ac3c residue of H-(Ac3c)2-OMe correspond to folded conformations in the "bridge" region of the Ramachandran map. The structures of pBrBz-Ac3c-OH and Z-Ac3c-OH, however, are unusual in having a semi-extended conformation for the phi, psi angles. The N-terminal Ac3c residue of H-(Ac3c)2-OMe adopts a novel type of C5 conformation, characterized inter alia by an (amino) N. . .H-N (peptide) intramolecular hydrogen bond. While the acyl N alpha-blocking groups form trans amides (pBrBz-Ac3c-OH and Piv-Ac3c-OH), the urethane groups may adopt either the trans [Z-Ac3c-OH and t-Boc-Ac3c-OH (alpha-form)] or the cis amide conformations [t-Boc-Ac3c-OH(beta-form) and Z-Ac3c-OMe]. The five- and six-membered rings of the 5(4H)-oxazolone and the 2,5-dioxopiperazine, respectively, are planar. The four independent molecules in the asymmetric unit of the free alpha-amino acid are zwitterionic.

Amino Acids↗
PubMed1989

The effect of reconstituted bovine surfactant on pulmonary mechanics in infants with respiratory distress syndrome.

We performed sequential measurements of pulmonary mechanics following instillation of reconstituted bovine surfactant (surfactant TA) in 10 neonates with severe respiratory distress syndrome. The respiratory compliance did not increase significantly until six hours after surfactant administration, while the arterial oxygenation and radiographic appearance improved rapidly after surfactant therapy. Six infants developed clinically significant PDA between 24 hours and 48 hours after surfactant therapy, when the compliance decreased temporarily after initial improvement until the PDA was closed pharmacologically. In six cases airway resistance rose transiently following surfactant treatment, whereas PCO2 fell significantly in all cases by six hours after surfactant administration. We recommend that only inspired oxygen concentration should be adjusted without changing the pressure setting of a respirator for at least three hours after surfactant therapy.

Animals↗
PubMed1989

Augmented fragmentation of atrial activity upon premature electrical stimuli by verapamil.

The significance of fragmented activity obtained from the atrium during electrophysiologic study (EP study) was confirmed since it was always observed just at the onset of fibrillation. It was preceded by extra stimuli or atrial flutter, and the initial site of fragmentation varied from case to case. The premature-stimulus-induced widening of the atrial wave was observed in some cases who had normal size of atrium and no heart failure. The widening was augmented by administration of verapamil but not by procainamide, suggesting that for such widening or fragmented activity, slow-fiber-mediated conduction seems to be responsible. One case with intraatrial reentrant tachycardia developed fragmentation lasting for 1.0 second after verapamil. Therefore, some apparently normal atria may have a subclinical electrophysiologic abnormality that can be disclosed by premature stimulations or verapamil.

Adolescent↗
PubMed1989

Attenuation of the vasoconstrictor action of neuropeptide-Y by calcium-channel blockers.

Neuropeptide-Y (NPY) was administered intracoronarily in dogs to see the modification of its vasoconstrictor action by the calcium (Ca)-channel blockers nisoldipine (0.1 microgram/kg) and nifedipine (1 microgram/kg). Dogs were anesthetized and the left circumflex artery was cannulated without opening the chest by using a specially designed cannula perfused at constant pressure. The change in coronary flow due to NPY was determined before and after the systemic administration of the two Ca-channel blockers. With administration of 1 to 2 nmol of NPY, coronary blood flow decreased maximally by 23.4 +/- 7.8% without changes in perfusion pressure or central venous pressure and it became significantly less after nisoldipine: 16.0 +/- 5.7% (p less than 0.02). A similar attenuation in the decrease in coronary flow was observed in the nifedipine study: 23.2 +/- 7.5% to 12.0 +/- 6.7% (p less than 0.02). A fall in systemic arterial blood pressure was observed after administration of both Ca-channel blockers, but it was significant only after nisoldipine (p less than 0.01). Nonsignificant increases in heart rate were observed after both drugs. Nisoldipine seemed to attenuate the NPY-induced vasoconstriction in dogs, and its equimolar potency is about ten times that of nifedipine.

Animals↗
PubMed1989

Urinary prostaglandins and renal function in obstructive jaundice.

Changes in urinary prostaglandin E2 (PGE2), 6-keto PGF1 alpha, and thromboxane (TXB2) excretion in 12 patients with obstructive jaundice were observed in relation to renal function and the renin-angiotensin (R-A) system. In obstructive jaundice before percutaneous biliary drainage the creatinine clearance (CCr) was significantly lower (p less than 0.001) and the PGE2 and plasma angiotensin II (AII) concentrations were significantly higher (p less than 0.005 and p less than 0.005, respectively) than those in normal subjects. Both 6-keto PGF1 alpha and TXB2 were widely distributed. When CCr returned to normal after drainage, PGE2 and plasma AII also returned to normal, but when CCr decreased after drainage, PGE2 and plasma AII increased. Before drainage, PGE2 correlated negatively with CCr (r = -0.72, p less than 0.01) and positively with plasma AII(r = 0.69, p less than 0.02). 6-Keto PGF1 alpha correlated positively with serum total bilirubin (r = 0.66, p less than 0.02). The percentage change in PGE2 after drainage correlated negatively with that in CCr (r = -0.95, p less than 0.005). The percentage chang in plasma AII correlated positively with that in urine PGE2 (r = 0.94, p less than 0.005) and negatively with that in CCr (r = -0.85, p less than 0.02). These results suggest that PGE2 is closely related to the R-A system and might assist in the maintenance of renal circulation in obstructive jaundice.

6-Ketoprostaglandin F1 alpha↗
PubMed1989

[Clinical study of intrahepatic arterial infusion of unresectable hepatoblastoma and hepatocarcinoma in children].

Six cases of unresectable hepatic cancer in infant were treated with intra-arterial infusion therapy. The histological types were hepatoblastoma and hepatocellular carcinoma, 3 cases respectively. The clinical stages were 1 recurrent case in I, 1 in IIIA, 2 in IIIB and 2 in IV. Seldinger method and cannulation at laparotomy were employed in 4 cases and 2 cases, respectively. In the eldest case, a catheter with dual lumen reservoir developed in our department was inserted, making it possible to infuse drugs into hepatic artery and cutting off hepatic arterial blood flow temporarily. The anticancer drug used was ADM, CDDP, 5-FU, THP-ADM, and MMC; antiAFP-anticancer drug conjugate missile therapy was employed in 4 cases. According to image diagnosis, reduction or necrosis of tumor was observed in 5 cases. In all cases, AFP scores decreased. In 5 dead cases, 4 cases died of tumor enlargement (average survival time 16.3 months); 1 case died of DIC during chemotherapy. The other case could eventually undergo complete resection and is now alive. Intra-arterial infusion therapy seemed to be useful for patients of infant unresectable hepatic cancer.

Adolescent↗
PubMed1989

Effects of recombinant human granulocyte colony stimulating factor (rG-CSF) on murine myeloid leukemia: stimulation of proliferation of leukemic cells in vitro and inhibition of development of leukemia in vivo.

We have established an experimental murine myeloid leukemia model and investigated the effects of recombinant granulocyte colony stimulating factor (rG-CSF) on myeloid leukemia in vitro and in vivo. rG-CSF stimulated colony formation by the leukemic cells in semisolid agar medium, and exponential growth of the clonogenic cells in suspension medium. Thus, rG-CSF was able to stimulate both the differentiation and self-renewal processes of the leukemic stem cells in vitro. However, 14 consecutive daily injections of rG-CSF prolonged the mean survival time of the mice implanted with the leukemic cells. This effect of rG-CSF was accompanied by a delay in the emergence of the blast cells in peripheral blood and by a decreased blast population in the spleen, suggesting that development of leukemia was suppressed in the rG-CSF-treated-mice. The prolongation of the survival time by rG-CSF was more evident when rG-CSF was administered in therapeutic combination with cyclophosphamide. These results indicate that the effect of rG-CSF on the development of leukemia is not exactly predicted from in vitro experiments.

Animals↗
PubMed1989

[Reservoir implanted arterial infusion therapy in liver cancer with replaced right hepatic artery].

Seven cases of liver cancer with replaced right hepatic artery were treated with arterial infusion therapy using implanted reservoir. The reservoir was surgically implanted in all cases. In 5 cases, right hepatic artery ligation was done simultaneously. TAE via right hepatic artery and ligation of middle and left hepatic artery was done in 2 other cases. ADM, CDDP, MMC, 5-FU and Lentinan were used. As the result, decrease in tumor size or necrosis of tumor was found in 3 cases of hepatomas, necrosis of tumor was found in 1 of three cases of metastatic liver cancer and remarkable decrease in tumor size and normalization of CEA level were found in another case. Arterial infusion therapy using implanted reservoir for the cases with variation would be effective with the combination of hepatic ligation or TAE.

Aged↗
PubMed1989

Influence of sulfhydryl agents on cytoskeleton in cultured human trabecular cells.

The effects of three sulfhydryl agents on the cytoskeletal systems of cultured human trabecular cells were examined by the immunofluorescence method. Incubation with iodoacetamide or N-ethyl maleimide (10(-6) M, 10(-5) M, and 10(-4) M) caused a marked alteration on the actin and microtubule organization, but had little effect on the structural integrity of the vimentin intermediate filaments. Incubation with p-chloromercuribenzene sulfonate (10(-6) M, 10(-5) M, and 10(-4) M) caused no remarkable changes in the three major cytoskeletal systems. These findings suggest that the trabecular cell cytoskeleton plays an important role in increasing the aqueous outflow facility after treatment with the sulfhydryl agents, iodoacetamide and N-ethyl maleimide.

4-Chloromercuribenzenesulfonate↗
PubMed1989

[Autopsy cases of glioblastoma multiforme: treatment results of high-dose fractionated radiation therapy and CT scan findings].

Six autopsy cases of glioblastoma multiforme in cerebral hemisphere were examined by large histological preparations. They were treated by surgery and high-dose fractionated radiation therapy (5 Gy twice weekly). Their morphological changes were compared to the last CT and radiation field and total doses. Four out of six cases showed small residual tumor. One case showed extensive necrosis of the tumor and brain. The other case exhibited no tumor tissue at all. Spongy degeneration of the white matter associated with astrocytosis and macrophage infiltration extended sometimes beyond the local irradiation field. These white matter changes were easily occurred in the previous peritumoral edema where tumor cell infiltration was frequently observed. Residual tumor cells consisted of small anaplastic cells, which might be radioresistant and recur. Enhancement effect of CT scan showed tumor tissue and radiation necrosis with vascular proliferation.

Adult↗
PubMed1989

[New quantitative method for non-invasive monitoring of tissue blood oxygenation by near infrared spectrophotometry].

The near infrared absorption spectra was measured with the transmitted light through rat brain under the various condition. The absorbance changes below 780 nm were attributable to hemoglobin (Hb) in the brain tissue, whereas those above 780 nm were associated with both Hb and cytochrome oxidase. To eliminate possible interference from cyt. oxidase, two wavelengths, 750 nm and 780 nm, were used to measure Hb oxygenation in the tissue. The absorbance changes in human blood cell suspensions were measured with changes in hematocrit values in the optical cuvette. At two wavelengths 750 nm and 780 nm, there was a linear relationship between absorbance changes and hematocrit values. Through these in vitro studies, the following equation (1) and (2) were obtained to monitor quantitatively the changes of oxy-Hb content (delta Hb O2) and total-Hb content (delta Hb Vol.) in the living tissue. These are (1) delta Hb O2 = -1.15 delta A 750 + 1.39 delta A 780, (2) delta Hb Vol. = -0.29 delta A 750 + 0.59 delta A 780. The studies using these equations showed that the oxy-Hb content in the brain was decreased as the O2 concentration in inspired gas was lowered with a half of Hb deoxygenated at 7% O2. The reliability of these equations was examined under the various conditions in situ such as CO2 inhalation, intravenous injection of Ca2+-blocker nicardipine, hemorrhage and retransfusion. These results confirmed that these equations derived from in vitro studies, were successfully applied to the in situ measurements of the oxygenation state of Hb in the living tissues.

Animals↗
PubMed1989

[Exercise testing of the chronic effects of bunazosin hydrochloride on dilated cardiomyopathy].

Bunazosin hydrochloride was administrated in 3-mg oral doses to the 10 patients (6 males and 4 females, average 49.9 years) with dilated cardiomyopathy (DCM) of class II in the NYHA functional classification. Then we observed the changes in their hemodynamics at rest, chest X-ray, echocardiography, humoral factors and symptom-limited exercise tolerance with treadmill testing before treatment and 4 and 8 weeks after administration. All but the left ventricular end-diastolic diameter after 8 weeks were unchanged. Of the humoral factors, only aldosterone decreased significantly during the treatment. On the other hand, the duration of symptom-limited exercise was prolonged significantly, and for a given exercise load, a reduction of heart rate and systolic blood pressure as well as a drop in the PRP occurred at 8 weeks after administration. Therefore, bunazosin appears to improve cardiac function and exercise tolerance in the patients with DCM, at dosages which do not affect hemodynamics at rest.

Adolescent↗