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Biomedical subjects

Y Aoki

Publications and source records attributed to Y Aoki.

At least 451 records · Page 25Linked to original sources
PubMed1993

Antithrombotic effect of recombinant human soluble thrombomodulin on endotoxin-induced disseminated intravascular coagulation in rats.

Thrombomodulin (TM) is an endothelial cell membrane glycoprotein which neutralizes thrombin procoagulant activity and accelerates the thrombin-catalyzed activation of protein C. We expressed recombinant human soluble TM (rhs-TM) in Chinese hamster ovary cells and compared the effects of rhs-TM and heparin on endotoxin-induced experimental disseminated intravascular coagulation (DIC) in rats. Experimental DIC was induced by a continuous intravenous infusion of endotoxin for four hours. rhs-TM or heparin was infused simultaneously with endotoxin. Treatment with rhs-TM significantly reversed the endotoxin-induced changes in significantly reversed the endotoxin-induced changes in following parameters: platelet count, fibrinogen level and fibrinogen and fibrin degradation products. Furthermore, glomerular fibrin deposits elevated by endotoxin treatment were reduced by the rhs-TM administration. Heparin showed the similar effects to rhs-TM. Activated partial thromboplastin time (APTT) in rats receiving rhs-TM were slightly longer than APTT in endotoxin-treated rats, but rats receiving heparin had much more prolonged APTT. From these results, we concluded that rhs-TM may be useful for the clinical treatment of DIC while having only minor adverse effects on APTT.

Animals↗
PubMed1993

Analysis of the results of combined therapy for maxillary carcinoma.

BACKGROUND: Maxillary sinus carcinomas usually are locally advanced. A wide variety of modalities, including surgery, radiation therapy, and intraarterial chemotherapy, alone or in combination, have been used. However, there is still much controversy with regard to the optimum treatment. METHODS: From 1972 to 1986, 108 patients with squamous cell carcinoma of the maxillary sinus were treated at the Department of Radiology, University of Tokyo Hospital. From 1972 to 1974 (the first period), the treatment consisted of operation for reduction of tumor volume, daily cleaning of the maxillary antrum, 20 Gy of postoperative radiation therapy, and intraarterial infusion of 1500 mg of 5-fluorouracil (5-FU) and 3000 mg of 5-bromodeoxyuridine (BUdR). From 1975 to 1979 (the second period), the radiation dose was reduced to 10 Gy, and intraarterial infusion of 5-FU and BUdR was not performed. Surgery for reduction of tumor volume and daily cleaning of the antrum played a major role in this period. From 1980 to 1982 (the third period), daily cleaning of the antrum was not performed. Instead, the dose of radiation was increased to 50-60 Gy. From 1983 to 1986 (the fourth period), more extensive surgery to resect the tumor en bloc was introduced. The radiation dose was increased to 70 Gy. Intraarterial infusion of 3750 mg of 5-FU and 120 mg of cisplatin also was administered. RESULTS: The 5-year survival rate was 46% in the first period, 24% in the second period, 7.2% in the third period, and 53% in the fourth period. In the third period, there were more cases in which death resulted from a cause other than local failure, such as distant metastasis, pneumonia, or secondary primary cancer. Since 1984, we planned treatment with computed tomography (CT) and used the linear accelerator with a multileaf collimator to treat patients with an irregular field of irradiation. These have made it possible to administer radiation therapy in doses as high as 70 Gy without severe complications and improve the survival rate, especially for T4 disease. CONCLUSIONS: Radiation plays an important role in sterilizing malignant cells that cannot be removed by operation. The dose of radiation should be determined according to the volume of residual tumor. Careful treatment planning is required to irradiate the tumor adequately and reduce complications.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1993

Induction of polarizing activity by retinoic acid occurs independently of duplicate formation in developing chick limb buds.

Retinoic acid (RA) is known to mimic the action of the zone of polarizing activity (ZPA) in inducing the formation of anteroposterior duplicates in the chick limb bud. Although RA had been thought to be a morphogen produced by the ZPA, recently we (Noji et al., 1991) and Wanek et al. (1991) independently concluded that RA induces polarizing activity in cells at the anterior margin of the chick limb bud. In this study, we examined the distribution of RA-induced polarizing activity in the limb bud. At first, RA-containing beads were implanted into various regions of stages 20-23 limb buds. After 24 hr, we grafted tissue fragments from sites adjacent to the RA beads into the anterior margin of host limb buds. High polarizing activity was induced in anterior-distal and apical mesoderm regions immediately under the apical ectodermal ridge (AER) when beads presoaked in 1 mg/ml RA were grafted to anterior sites at stages 19-20. However, in mesoderms distant from the AER, even if adjacent to the implanted RA bead, only low activity was induced. Although implantation of beads soaked in a high concentration (10 mg/ml) of RA did not result in duplications but rather in truncations of the limbs, the apical mesodermal cells in these limbs were converted to ZPA cells, indicating that induction of polarizing activity by RA can occur independently of duplicate formation. The ability to respond to RA treatment was rapidly lost in the cells along the anterior margin of stage 22 limb buds. When the anterior AER was removed, the induction of polarizing activity in the anterior margin of limb buds was markedly reduced. Thus, the AER seems to be necessary for the RA-directed induction of polarizing activity.

Animals↗
PubMed1993

Mechanism of thrombocytopenia in liver cirrhosis: kinetics of indium-111 tropolone labelled platelets.

Using indium-111 tropolone-labelled platelets, a study of platelet kinetics was performed on the basis of the relationship between platelet count, platelet survival time, platelet dynamics, platelet-associated immunoglobulin G (PA-IgG) and splenic volume in 31 patients with liver cirrhosis and a platelet count of less than 100 x 10(9)/l. The mean platelet count was 46.6 +/- 25.3 x 10(9)/l, and the mean platelet survival time was 6.50 +/- 1.33 days. The mean uptake into the spleen was 43.2% +/- 14.8% on the 1st day, and 53.7% +/- 14.3% on the 7th day. The mean PA-IgG level was 107.6 +/- 66.0 ng/10(7) platelets in five patients with chronic active hepatitis who were studied as controls, the mean platelet count was 197 +/- 30 x 10(9)/l, the mean platelet survival time 9.33 +/- 0.78 days, and the mean PA-IgG 21.2 +/- 2.9 ng/10(7) platelets. The former two parameters were significantly higher (P < 0.05), and the latter significantly lower (P < 0.05). In liver cirrhosis, the platelet count showed a positive correlation with the platelet survival time and a negative correlation with PA-IgG and the splenic volume. These results suggest that the increases in both the splenic platelet pool and platelet destruction in the spleen through immunological mechanisms may influence thrombocytopenia in liver cirrhosis.

Blood Platelets↗
PubMed1993

Stiffening of connective tissue in elderly diabetic patients: relevance to diabetic nephropathy and oxidative stress.

Limited joint mobility seen in diabetes mellitus is thought to be the result of stiffening of periarticular connective tissue, which is presumably derived from increased cross-linking of collagen related to advanced glycation end products. In this study the extent of the stiffening of connective tissue was measured by the passive extension angle of the metacarpophalangeal joints in 205 elderly diabetic patients. Association with diabetic nephropathy, with which advanced glycation end products have recently been demonstrated to increase, and metabolic abnormalities were also considered. The angle of the metacarpophalangeal joints was significantly correlated with age (r = -0.24, p < 0.01), and was significantly smaller in men than in women (p < 0.01). The angle demonstrated a decrease in association with diabetic retinopathy and nephropathy, and only the association with nephropathy was significant (p < 0.05). The angle was weakly, but significantly, correlated with serum thiobarbituric acid reactants as a measure of lipid peroxides (r = -0.15, p < 0.05), triglyceride (r = -0.20, p < 0.01) and HDL cholesterol (r = 0.19, p < 0.01), but not with blood glucose (r = 0.02), HbA1c (r = 0.06) or duration of diabetes (r = -0.05). In addition, the angle in 14 non-diabetic patients on haemodialysis was significantly (p < 0.05) smaller than that in age- and sex-matched normal subjects. Thus, it was indicated that the stiffening of connective tissue was associated with diabetic nephropathy, serum lipid peroxide and dyslipidaemia. Stiffening of connective tissue seems to be more affected by oxidative stress than non-enzymatic glycation per se.(ABSTRACT TRUNCATED AT 250 WORDS)

Albuminuria↗
PubMed1993

Prenatal paternity testing with DNA analyses.

Two PCR amplified loci and 3 single locus DNA probes were applied in a paternity case in which a married woman became pregnant after being raped. DNA analysis were performed using samples from the woman, her husband and amniotic fluid cells taken during the 16th week of pregnancy. The combined probability of paternity for her husband was calculated as 0.999997107. The application of PCR analyses and single locus DNA probes were considered to be extremely informative in prenatal paternity testing.

Amniotic Fluid↗
PubMed1993

Both medullasin and human leukocyte elastase are essentially devoid of elastinolytic activity.

Elastinolytic activity of medullasin was investigated precisely and compared with that of human leukocyte elastase, because the structure of medullasin is quite similar to that of human neutrophil elastase, which was reported to have elastinolytic activity. When elastinolytic activity of medullasin and human leukocyte elastase was determined by employing unstained elastin fibers and measuring the increase in 280-nm absorbance of the supernatant, elastinolytic activity amounting to several percent of that of porcine pancreas elastase was apparently observed. However, the susceptibility of elastin preparations to these proteases was proportional to their hydroxyproline content. Both medullasin and human leukocyte elastase digested collagen fibers obtained from bovine Achilles tendon to the same extent as collagenase from Clostridium histolyticum. When elastinolytic activity was determined by employing elastin fibers stained with orcein, both proteases showed negligible elastinolytic activity. The activity remained negligible even when the pH or ionic strength of the reaction mixture was altered. These results indicate that medullasin and human leukocyte elastase are essentially devoid of elastinolytic activity, and that apparent elastinolytic activity observed when unstained elastin fibers were employed as the substrate is due to the digestion of collagen fibers mingled with elastin preparations.

Collagen↗
PubMed1993

Biological characterization of cyclothialidine, a new DNA gyrase inhibitor.

Cyclothialidine is a new DNA gyrase inhibitor isolated from Streptomyces filipinensis NR0484. Structurally, it belongs to a new class of natural products containing a unique 12-membered lactone ring that is partly integrated into a pentapeptide chain. Cyclothialidine was found to be one of the most active of all the DNA gyrase inhibitors tested in the DNA supercoiling reaction of Escherichia coli DNA gyrase; 50% inhibitory concentrations (in micrograms per milliliter) of 0.03 (cyclothialidine), 0.06 (novobiocin), 0.06 (coumermycin A1), 0.66 (norfloxacin), 0.88 (ciprofloxacin), and 26 (nalidixic acid) were found. In addition, DNA gyrases from gram-positive species were inhibited equally as well as DNA gyrase from E. coli. Cyclothialidine also inhibited the in vitro DNA replication directed from oriC of E. coli. Among the bacterial species tested, only Eubacterium spp. were inhibited by cyclothialidine, suggesting that it can enter the cells of Eubacterium and exert antibacterial activity through interference with the DNA gyrase within the cells, although its penetration into most bacterial cells appears to be poor. These results provide a basis for cyclothialidine to be a lead structure for novel antibacterial agents with DNA gyrase inhibitory activities.

Animals↗
PubMed1993

Ro 09-1470 is a selective inhibitor of P-450 lanosterol C-14 demethylase of fungi.

Ro 09-1470 is a new antifungal agent that belongs to a series of compounds characterized by a tetrahydropyran skeleton with glycine and alkenyl side chains and that inhibits P-450 lanosterol C-14 demethylase (P-450(14DM)) of fungi (Y. Aoki, T. Yamazaki, M. Kondoh, Y. Sudoh, N. Nakayama, Y. Sekine, H. Shimada, and M. Arisawa, J. Antibiot. 45:160-170, 1992; S. Matsukuma, T. Ohtsuka, H. Kotaki, H. Sawairi, T. Sano, K. Watanabe, N. Nakayama, Y. Itezono, M. Fujiu, N. Shimma, K. Yokose, and T. Okuda, J. Antibiot. 45:151-159, 1992). We have studied the compound's mode of interaction with fungal P-450(14DM) and its selectivity for the fungal versus mammalian P-450 enzymes. Ro 09-1470 bound to the Saccharomyces cerevisiae P-450(14DM) by coordinating to the heme with one-to-one stoichiometry. Unlike the azole compounds, it interacted with both ferric and ferrous heme. It was active also against the P-450(14DM) of Candida albicans. Ro 09-1470 preferentially inhibited the yeast P-450(14DM), showing a 50% inhibitory concentration (IC50) of 0.47 to approximately 1.1 microM, which is much lower than the IC50s for rat hepatic P-450s catalyzing cholesterol biosynthesis (IC50 = 341 microM), p-nitroanisol O-demethylation (> 1,000 microM), aniline hydroxylation (> 1,000 microM), and aminopyrine N-demethylation (920 microM). The degree of selectivity for yeast P-450 was higher than that of ketoconazole.

Animals↗
PubMed1993

Esthesioneuroblastoma. A report of seven cases.

The biologic behavior of esthesioneuroblastoma in seven patients, treated from 1978 to 1989, is reviewed. The patients were initially treated with surgical resection (2 cases), radiation alone (1 case) or a combination of radiation and surgery (4 cases). The radiation dose ranged from 30 to 62 Gy. Operations were performed via a transmaxillary approach (2 cases), lateral rhinotomy approach (3 cases) and craniofacial approach (1 case). Four of the seven patients experienced local recurrence, occurring after disease-free intervals as long as 6 years. The other three patients died of distant metastasis within one year after initial treatment. The effectiveness of radiation therapy varied, and in some patients a dose of 60 Gy was not enough to control microscopic disease. One patient developed bone marrow metastases which was fatal due to the ensuing pancytopenia. One patient developed a brain metastasis. Hyams' histopathologic staging of the tumor appeared to be related to prognosis.

Adolescent↗
PubMed1993

Effects of sodium and chloride ions on blood pressure in deoxycorticosterone acetate-treated rats.

The effects of sodium (Na+) and chloride ions (Cl-) on blood pressure were studied in rats treated with deoxycorticosterone acetate (DOCA). Four groups were prepared, each consisting of male Wistar rats that underwent heminephrectomy and administration of DOCA: the control group was maintained with tap water, the NaCl group with tap water containing 1% sodium chloride, the NaCit group with tap water containing 1.67% sodium citrate (including an equivalent dose of Na+ to 1% NaCl), and the ChoCl group with tap water containing 1.15% choline chloride (including an equivalent dose of Cl- to 1% NaCl). The time-course of systolic blood pressure showed only slight change in blood pressure in the control and ChoCl groups, and in the NaCl and NaCit groups. The rotational correlation time, an index of the fluidity of erythrocyte membrane, with spin-labeling of 16-doxyl-stearic acid, was significantly (p < 0.05) higher in the NaCl and NaCit groups than in the control group, indicating an increase in the membrane fluidity, i.e., membrane fragility. The sodium, potassium ions-activated adenosine triphosphatase (Na+,K(+)-ATPase) activity of the erythrocyte membrane was decreased to 22% (P < 0.01) and 24% (P < 0.01) in the NaCl and NaCit groups, respectively, compared with the control groups; this activity was decreased to 43% in the ChoCl group (P < 0.05). The Ca(2+)-ATPase activity showed similar changes. In contrast, there were no marked differences in the erythrocyte electrolyte level between the groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

[High-dose chemoradiotherapy combined with recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) followed by autologous peripheral blood stem cell transplantation (PBSCT) in a case of refractory acute myelogenous leukemia (AML)].

Recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) stimulates the growth of myeloid leukemic cells and increases their susceptibility to cell-cycle specific agents. We treated a patient with acute myelogenous leukemia (AML) in a state of second resistant relapse, with high-dose chemoradiotherapy combined with rhGM-CSF (total body irradiation: TBI 3Gy x 4, on days -8 & -7; cytosine arabinoside: Ara-C 3g/m2, iv, q12h, on days -5-2; rhGM-CSF 250 micrograms/m2/day, cont.iv, on days -5-2) followed by autologous peripheral blood stem cell transplantation (PBSCT). In this case, rhGM-CSF enhanced the proliferation of leukemic cells in vitro. The test dose of rhGM-CSF (84 micrograms/m2 over 8 hours) also promoted leukemic cell proliferation in vivo, resulting in an increase in the percentage of leukemic cells in the peripheral blood and reappearance of chromosomal aberrations in the bone marrow. The toxicity of rhGM-CSF-combined conditioning regimen included fever and mild liver damage. The patient achieved a complete remission lasting for 2 months, then relapsed. The rhGM-CSF-combined conditioning regimen was tolerated by this patient, but further studies will be required to confirm not only its safety but also its effectiveness in the treatment of refractory AML.

Adult↗