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Biomedical subjects

Y Aoki

Publications and source records attributed to Y Aoki.

At least 397 records · Page 22Linked to original sources
PubMed1995

Morphological aspects of cell wall formation during protoplast regeneration in Candida albicans.

The dynamics of cell wall regeneration in Candida albicans protoplasts was investigated by fluorescence microscopy using a new fluorescent dye, Fungiflora Y, which specifically binds to beta-linked polysaccharides, as well as by electron microscopy. When freshly prepared protoplasts were incubated in osmotically stabilized medium, multiple binding sites of Fungiflora Y were detected on their surface within 15 min of incubation. At this initial stage of reversion, protoplasts began to form microfibrils outside the cytoplasmic membrane. From 1 h onward, the whole cell surface displayed a bright fluorescence. After 3 h of incubation, the reverting protoplasts were covered by an interwoven network of microfibrils. After 5 h of incubation, although most of the revertants had become osmotically resistant, regenerated cell walls in which the constituent materials appeared highly integrated were observed to be still monolayered in profile. Cell wall regeneration was complete after 24 h of incubation, at which time the reverted cells were capable of proliferating.

Candida albicans↗
PubMed1995

[Clinical statistics on outpatients during a ten-year period (1983, 10-1993, 12) at Department of Urology, Fukui Medical School].

A clinical statistic survey was carried out on the patients and disease experienced at the outpatient clinic of our Department of Urology, between 1983 and 1993. Although the number of newly diagnosed patients was rather constant, the total number of outpatients gradually increased every year, and the average and median age of newly diagnosed patients became higher. The major disease categories were infectious and neoplastic disorders.

Adolescent↗
PubMed1995

[Study of anti-tumor effects of hyperthermia combined with hydralazine on experimental tumor].

We analyzed tumor growth delay in experimental tumors after hyperthermia alone, hydralazine (HDZ) injection alone and the combination of these modalities. We also analyzed the energy parameter (ATP/Pi ratio) obtained by 31P-MRS (magnetic resonance spectroscopy). The purpose of this study was to evaluate the usefulness of 31P-MRS as an index of anti-tumor effect. FM3A tumor cells were transplanted subcutaneously in the hind legs of C3H/He mice. We dipped the tumors into a heated circulating water bath. 31P-MRS was performed with a CSI spectrometer. The anti-tumor effect obtained with HDZ alone was insignificant, but combined treatment with hyperthermia and HDZ had a significant synergistic effect. The ATP/Pi ratios for all groups treated separately with HDZ or hyperthermia were not different from the control, but the ATP/Pi ratio decreased after combined use of these agents. There was a significant correlation between the decrease in ATP/Pi ratio and tumor growth delay. We observed a direct relation between the delay in tumor growth and the decline in ATP/Pi ratio after combined treatment with HDZ and hyperthermia. The ATP/Pi ratio 24 hr after treatment may be useful in predicting the efficacy of the combined use of HDZ and hyperthermia.

Adenosine Triphosphate↗
PubMed1995

[Verification of rotational conformation radiotherapy using megavoltage CT scanning].

Although portal imaging is a promising method of verification during static multi-port irradiation, it cannot be applied directly to dynamic irradiation such as rotational conformation with multi-leaf collimator movement. A real-time beam monitoring system based on megavoltage computed tomography scanning has been developed to establish a verification method for the rotational conformation technique. The exit beam through the patient is extracted by the same detector unit as that used for megavoltage scanning during the actual treatment. The beam edge is defined as the 50% level of the maximum dose of the detector array. Megavoltage computed tomography is done after patient setup and just prior to the actual irradiation. Detected beam pathways are overlaid on this image approximately every 1 sec. Therapists can monitor the correlation between the target and actual beam pathways on a real-time computer display. The accuracy of field edge detection has been proven to be less than 2 mm from various measurements. Field errors were identified in two of 54 sessions using this method. Although several limitations remain to be solved, the method presented is an useful tool for treatment verification of high accuracy radiation therapy, particularly rotational conformation irradiation.

Brachytherapy↗
PubMed1994

Radiation therapy in early glottic carcinoma: uni- and multivariate analysis of prognostic factors affecting local control.

PURPOSE: The purpose of this report is to clarify prognostic factors affecting local control of T1 and T2 glottic tumors and to define an optimal regimen for radiation therapy. METHODS AND MATERIALS: Two hundred and ten patients (199 males, 11 females, age range 30 to 86 years with an average of 62 years) with previously untreated invasive squamous cell carcinoma of the glottis were treated with radiation therapy at the University of Tokyo between January 1972 and December 1989. Endoscopic microsurgery was introduced as an integral part of treatment in 1974. From 1974 to 1979 the radiation dose was gradually reduced, reaching a mean of 20 Gy in 2 weeks in 1979. From 1980 to 1983, the total dose increased to 50.4 Gy, with a fraction size of 1.8 Gy, over a mean of 5.6 weeks. From 1984 onward, the mean total radiation dose increased to 60 Gy with a fraction of 2 Gy. RESULTS: Recurrence-free 5 year survival rates for T1a, T1b, and T2 were 79%, 73%, and 67%, respectively. When the relationship between radiation dose and local control rates was analyzed for each year from 1974 to 1989, total doses were strongly associated with local control for patients with T1a disease. Age, sex, daily dose, total dose, radiation machine (Co-60 or 10 MV Lineac), treatment technique (anterior wedged pair or parallel opposed fields), treatment volume, use of endoscopic microsurgery, and involvement of the anterior commissure were examined for effects upon relapse-free survival in T1a disease by uni- and multivariate analysis. Total dose was the only significant factor for T1a disease (p < 0.02). The effect of these variables upon relapse-free survival in T2 disease as well as the effect of cord mobility, and number of involved sites was examined by multivariate analysis. Total dose (p < 0.03), cord mobility (p < 0.05), and number of involved sites (p < 0.04) significantly affected relapse-free survival in T2 disease. CONCLUSION: At least 50 Gy is required for treatment of T1 disease when 2 Gy is used as a daily dose, even if endoscopic microsurgery is performed. Better local control of T2 disease in patients with impaired cord mobility or more than three involved sites leads to an improved prognosis; we recommend doses of at least 70 Gy or use of hyperfractionation in such patients with these factors. Although the daily dose did not significantly affect prognosis in multivariate analyses, 1.8 Gy is not recommended for treatment of T2 tumors instead of 2 Gy.

Adult↗
PubMed1994

Thermoradiotherapy in the treatment of locally advanced nonsmall cell lung cancer.

PURPOSE: To improve the treatment results of locally advanced non-small cell lung cancer (NSCLC), we have been conducting a clinical trial using regional hyperthermia combined with radiotherapy. METHODS AND MATERIALS: Between 1985 and 1990, 19 patients were treated. All cases except one were regarded as initially unresectable. There were 10 Stage IIIA cases and nine Stage IIIB cases. In 10 cases thermoradiotherapy was used definitively, and in the other nine cases preoperatively. Radiotherapy was administered with conventional fractionation. Total dose ranged from 42 to 80 Gy (mean 62.9 Gy) for definitive treatment cases, and 38 to 47 Gy (mean 40.6 Gy) for preoperative cases. Radiofrequency (RF) capacitive hyperthermia was administered twice weekly, immediately after radiotherapy. Total sessions of hyperthermia ranged from 5 to 16 times (mean 9.0) for definitive treatment cases and 3 to 8 times (mean 6.7) for preoperative cases. RESULTS: The results of thermoradiotherapy group (HTRT group) were compared with our historical control group (RT group); initially unresectable Stage III NSCLC irradiated definitively with 50 Gy or more (26 cases), or became resectable after radiotherapy and operated (4 cases). As for initial response, there were 5 complete responses (CRs), 13 partial responses (PRs), and 1 no change (NC) (CR rate 26%, response rate 95%) in the HTRT group, whereas there were no CR, 21 PRs, and 9 NCs in the RT group (CR rate 0%, p < 0.005, response rate 70%, p < 0.05). Overall 3-year local relapse-free survival and survival rate for the HTRT group was 73% and 37%, respectively, and 20% and 6.7%, respectively, for the RT group (p < 0.01, p < 0.01). The rate of death from uncontrolled primary disease for the HTRT group was significantly lower than for the RT group (21% vs. 53%, p < 0.03). CONCLUSION: Although the number of cases is rather small, thermoradiotherapy in the treatment of locally advanced NSCLC is promising in raising resectability, local control, and, thus, long-term survival.

Adolescent↗
PubMed1994

Real-time beam monitoring in dynamic conformation therapy.

PURPOSE: Although portal imaging is a promising method of verification during static multiport irradiation, it cannot be applied directly to dynamic irradiation such as rotational conformation with multileaf collimator movement. A real-time beam monitoring system based on megavoltage computed tomography scanning has been developed to establish a verification method for the rotational conformation technique. METHODS AND MATERIALS: Exit beam through the patient is extracted by the same detector unit as used for megavoltage scanning during the actual treatment. Beam edge is defined as the 50% level of the maximum dose of the detector array. Megavoltage computed tomography is done after patient setup and just prior to the actual irradiation. Detected beam pathways are overlaid on this image approximately every 1 s. Therapists can monitor correlation between the target and actual beam pathways on a real-time computer display. RESULTS: The accuracy of field edge detection has been proven to be less than 2 mm from various measurements. Real-time monitoring is more useful in rotational conformation than in static multiport irradiation due to dynamic movement of the collimator. Field errors were identified in two of 54 sessions using this method. CONCLUSIONS: Although several limitations remain to be solved, the method presented is a useful tool for treatment verification of high accuracy radiation therapy, particularly rotational conformation irradiation.

Brain Neoplasms↗
PubMed1994

Enhanced synthesis of metallothionein as a possible cause of abnormal copper accumulation in LEC rats.

Long-Evans rats with a cinnamon-like coat color (LEC) is an inbred strain accumulating copper (Cu) in the liver abnormally and showing spontaneous hepatitis and hepatoma. The present study was intended to clarify how Cu accumulates in the LEC rat liver. For this purpose, the distribution profiles of Cu and zinc (Zn) and the inducibility of metallothionein (MT) synthesis were examined in the liver between Cu-loaded Long Evans agouti (LEA, the original strain of LEC) rats and were compared with those in control LEC rats. LEA rats (female, five weeks old) were injected subcutaneously with CuCl2 daily at a dose of 3 mg Cu/kg body weight for 2, 4, 6, and 9 days. The concentration of Cu (124 micrograms/g) accumulated in the LEA rat liver after four injections was comparable to that in control LEC rats. Only 20% of Cu in the liver of LEA rats was recovered in the supernatant fraction in the form of MT, while Cu in the LEC rat liver (113 micrograms/g) was recovered mostly in the supernatant fraction, and was bound to MT. Although the increased concentration of Cu in the LEA rat liver was further elevated after additional injections of Cu, the amount of MT did not increase further. The MT mRNA content in the LEA rat liver remained lower than that of LEC rats even after further injections of Cu. Therefore, the present results suggest that LEC rats can accumulate Cu at a high concentration in the liver because of their extremely high inducibility of MT.

Animals↗
PubMed1994

Bruton tyrosine kinase is tyrosine phosphorylated and activated in pre-B lymphocytes and receptor-ligated B cells.

The gene encoding Bruton tyrosine kinase (Btk) is known to be mutated in human X chromosome-linked agammaglobulinemia and in the Xid mouse. This kinase was examined in B lymphocytes before and after antigen receptor ligation and also in pre-B cells. Btk was found to be catalytically activated and tyrosine phosphorylated in response to anti-IgM stimulation in B cells. This kinase is also constitutively phosphorylated on tyrosine residues in pre-B cells. These findings point to a functional role for Btk in pre-antigen and antigen receptor signaling during B-cell development and provide a biochemical explanation for the X-linked genetic syndromes already linked to this kinase.

Agammaglobulinaemia Tyrosine Kinase↗
PubMed1994

Clonal expansion but lack of subsequent clonal deletion of bacterial superantigen-reactive T cells in murine retroviral infection.

Several studies have suggested that activation-induced apoptosis of Ag-specific CD4+ T cells leads to depletion of this subset during HIV infection. The bacterial superantigen, staphylococcal enterotoxin A (SEA), is known to induce activation-induced apoptosis in the TCR V beta-bearing CD4+ T cells in the periphery after clonal expansion of these cells. The murine retroviral model of AIDS (MAIDS), which is induced by LP-BM5 murine leukemia virus, shares many common features with HIV infection in humans, except that CD4+ T cells increase progressively in susceptible strains. In this study, we challenged SEA to MAIDS mice and examined whether this retrovirus affects the fate of the SEA-reactive CD4+ T cells in vivo. At 4 wk post-infection with LP-BM5 murine leukemia virus, clonal expression and subsequent deletion of SEA-reactive CD4+V beta 3+ T cells occurred normally after SEA administration, whereas in vitro proliferative responses were severely impaired. At 8 wk postinfection, the in vivo expansion of CD4+V beta 3+ T cells was evident, but not followed by clonal deletion, as late as 14 days after SEA administration. This expanding subset in the infected mice expressed the Fas Ag in the same amount as the same subset in uninfected controls. These findings suggest that activation-induced apoptosis of superantigen-reactive CD4+ T cells is interfered with in vivo during the course of MAIDS, which is not attributable to underexpression of the Fas Ag by the CD4+ T cells.

Animals↗
PubMed1994

Purification and properties of bovine liver holocarboxylase synthetase.

Holocarboxylase synthetase was purified 18,000-fold from bovine liver cytosol by a sequence of ammonium sulfate fractionation, alumina C gamma fractionation, DEAE-Sepharose CL-6B, EAH-Sepharose 4B, Sephacryl S-200 HR, Bio-Gel HTP, and Phenyl-Superose HR 5/5 chromatographies. Holocarboxylase synthetase activity was assayed using apopropionyl-CoA carboxylase from a patient with holocarboxylase synthetase deficiency as a substrate. Apopropionyl-CoA carboxylase was easily prepared from cultured lymphoblasts from this patient. Enzyme activity coincided with a 64,000-Da protein band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Additionally, the molecular mass of the native enzyme was estimated to be 60,000 Da by gel filtration on Sephacryl S-200 HR. These results suggest that purified holocarboxylase synthetase from bovine liver cytosol is a monomeric enzyme. Its Km value for biotin was estimated to be 13 nM.

Animals↗
PubMed1994

In vitro effects of OK-432 on irradiated mouse bone marrow cells.

PURPOSE: In vitro effects of OK-432 on irradiated mouse bone marrow cells are examined. METHODS AND MATERIALS: Bone marrow cells of BDF1 mouse (1 x 10(6) cells/ml) were incubated with alpha medium, 2% fetal calf serum and OK-432 in a CO2 incubator at 37 degrees C for 24, 48 and 72 h, respectively. After centrifugation, each supernatant was collected and used for conditioned medium in CFU-GM assay: Changes in CFU-GM as a function of incubation time and OK-432 dose was examined; changes of CFU-GM according to various doses of OK-432 were examined in two mouse strains, BDF1 and BALB/c mouse; changes in protective effect of OK-432 in terms of CFU-GM as a function of administration timing of OK-432 in relation to irradiation. As a radiation source, 137Cs at a dose rate of 500 cGy/min was used. RESULTS: The CFU-GM decreased with the incubation time when OK-432 was not administered, while it significantly increased with incubation time when OK-432 was added at 0.5 and 1.0 KE/ml at 48-72 h of incubation. The former showed marked increase at 48-72 h of incubation. CFU-GM of BDF1 mouse was always higher than that of BALB/c mouse for any dose of OK-432. CFU-GM per femur according to the timing of administration of OK-432 from 24 h before to 24 h after irradiation showed 10299 +/- 2300 (24 h before), 10783 +/- 2463 (3 h before), 10045 +/- 1501 (immediately after), 8504 +/- 1188 (3 h after), 4898 +/- 1212 (6 h after), 1214 +/- 736 (12 h after) and 181 +/- 113 (24 h after irradiation), respectively. CONCLUSION: OK-432 stimulates cultured mouse bone marrow cells to produce GM-CSF in vitro by direct contact action. This direct stimulating action of OK-432 on GM-CSF production of bone marrow cells can be kept from 24 h before to at least 3 h after irradiation.

Animals↗
PubMed1994

Regulation of recombinant human granulocyte colony-stimulation factor production using herpes simplex virus 1 thymidine kinase gene.

For chronic neutropenic patients requiring long-term injection of recombinant human granulocyte colony-stimulating factor (rhG-CSF), a cellular transplantation system that can produce this cytokine stably and deliver it in a regulatory manner would be advantageous. In this study we aimed at developing a regulation system at cellular level using suicide vectors. We introduced the herpes simplex virus type 1 thymidine kinase (HSV-TK) gene into the rhG-CSF-producing NIH3T3 cells and examined if ganciclovir (GCV) treatment of the cells could control the rhG-CSF production in vitro. The cells transfected with the HSV-TK gene showed a > 100-fold increase in sensitivity to GCV compared with the parent cells, and the median inhibitory dose of GCV to the transfected cells was less than 1.6 microM. The total amount of rhG-CSF production by these cells was strongly suppressed by GCV treatment. This regulatory method may be applicable to cytokine supplement gene therapy.

Ganciclovir↗
PubMed1994

Mechanisms for removal of copper from metallothionein by tetrathiomolybdate.

Mechanisms for removal of copper (Cu) from metallothionein (MT) by tetrathiomolybdate (TTM) were examined in vivo and in vitro using the LEC rat, which accumulates Cu as MT owing to the hereditary disorder of this strain. In our previous experiment, repeated intraperitoneal injections of TTM were shown to remove approximately two-thirds of the Cu from the liver, and the Cu remaining in the liver changed from soluble MT-bound forms to nonsoluble unidentified forms. The present single intravenous injection of TTM changed only part of the distribution in the soluble fraction, and dimeric MT was assumed to be formed. The liver supernatant was treated in vitro with high and low doses of TTM. The former treatment removed all Cu bound to MT and the Cu distributed to high molecular weight proteins, while the latter treatment produced dimeric MT. The results indicate that Cu accumulated as MT can be removed differently by TTM according to its relative dose both in vivo and in vitro. Excess TTM removes Cu completely from MT, leaving apothionein, while lesser TTM than Cu removes Cu incompletely, leaving MT with unoccupied sulfhydryl groups which coordinate with Cu intermolecularly to form dimeric and polymeric MT through the -S-Cu-S- bridge.

Animals↗
PubMed1994

Tyrosine phosphorylation of Blk and Fyn Src homology 2 domain-binding proteins occurs in response to antigen-receptor ligation in B cells and constitutively in pre-B cells.

Proteins that bind to discrete domains of the Blk, Fyn, Lyn, and Btk protein tyrosine kinases were examined in pre-B cells that had not been subjected to any external stimulation, as well as in nonstimulated and antigen-receptor-ligated B cells. Proteins that bind to the Src homology 2 domains of Blk and Fyn were identified in B cells that had been activated with anti-IgM but were not identified in unstimulated B cells. A number of Blk and Fyn Src homology 2 domain-binding phosphoproteins were also observed in pre-B cells that had not been stimulated in vitro. The phosphoproteins seen in activated B cells potentially represent substrates that play a role in the pathway of antigen-receptor-mediated signaling. Distinct signaling pathways involving distinguishable kinase substrates may be relevant in pre-B-cell-receptor-mediated cell survival during ontogeny. These results indirectly support models that predict constitutive ligand-independent signaling by the pre-antigen receptor during lymphoid ontogeny.

Animals↗
PubMed1994

End colostomy using stapling device.

Our experiences concerning the end colostomy using the stapling method are reported. The anvil which has been inserted to the proximal end of the colon and purse string suture with the skin is engaged the anvil shaft, and then, is fired. This operative procedure is simple, safe and convenient, and we can expect a uniform and satisfactory outcome. We applied this technique on 6 cases and have had no postoperative complications.

Adult↗