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Biomedical subjects

Y Sakurai

Publications and source records attributed to Y Sakurai.

At least 667 records · Page 37Linked to original sources
PubMed1979

Blastogenic potency of concanavalin-A-bound L1210 leukemic vaccine associated with its immunogenic activity.

Glutaraldehyde-treated L1210 murine leukemic cells induced immune resistance in mice when concanavalin-A (Con-A) was bound to their surface. They were not immunogenic when Con-A was separately inoculated, indicating requirement of vaccine-bound Con-A for enhancing immunogenic potency of the vaccine. Based on the finding that vaccine-bound Con-A induced in vitro blastogenesis of spleen cells 10 times as efficiently as unbound Con-A did, the association of blastogenic potency of Con-A-bound vaccine with its immunogenic activity was examined. The possibility of their association was supported by the finding that induction of immune resistance by vaccines was reduced when their blastogenic activities had been reduced by treatment of the vaccine with anti-Con-A antisera or by substituting succinyl-Con-A or other lectins for Con-A. Moreover, the fact that combined inoculations of Con-A-bound vaccine, assumed to be blastogenic to T cells, with anti-thymocyte sera, but not with cyclophosphamide or carrageenan, resulted in reduced production of resistant animals was also consistent with, but not proving, this possibility. Feasibility of this possibility was further supported by the finding that Con-A-bound vaccine did not induce immune resistance in animals that had been abrogated in blastogenic activity of spleen cells by prior administration of Con-A.

Animals↗
PubMed1979

[Aneurysm surgery in the older patients (author's transl)].

A series of 9 patients over 70 years of age with saccular aneurysms, operated on by a direct surgery is reviewed in order to discuss the aneurysm surgery in the older patients. The median age of the patients was 74 years, and median interval from the hemorrhage to surgery was 18 days. Operative mortality was 11% and morbidity was 33%. Result of intracranial aneurysm surgery in the older patients depends on the surgical technique for the arteriosclerosis. 1. Treatment of the aneurysm neck must be abandoned when a severe arteriosclerosis exists around it. Subsequent to exposure of the whole aneurysm, a complete reinforcement of the aneurysm wall should be undertaken. 2. Especially gentle manipulation of the brain is necessary since small arteries are easily pulled out from the sclerotic artery. 3. The cerebral veins must be preserved as well as possible to avoid the venous congestion, which easily causes an intracerebral hematoma following brain retraction. 4. The frequency of pre and postoperative complications is high, but through vigorous care, they are kept under control. 5. It is best not to judge the surgical indication simply by the chronological age, but rather to consider the physical age including the laboratory findings. Therefore, other than cases of severe arteriosclerosis, the same principles for surgical indication in younger patients should be used for older patients.

Aged↗
PubMed1979

Active efflux of daunorubicin and adriamycin in sensitive and resistant sublines of P388 leukemia.

Significantly decreased uptake and retention of daunorubicin (DAU) and Adriamycin (ADR) have been reported in sublines of P388 leukemia resistant to these anthracyclines. We studied the effects of inhibitors of oxidative phosphorylation on uptake and retention of DAU and ADR in order to characterize the transport process for these anthracyclines and to clarify further the alteration in resistant cells. In glucose-free medium, uptake of DAU and ADR was accelerated by metabolic inhibitors to a greater extent in resistant cells than in sensitive cells. Under these conditions, drug uptake was similar in sensitive and resistant cells. When glucose was added to the incubation medium in the presence of 2,4-dinitrophenol, efflux of DAU from both sensitive and resistant cells was observed. Net efflux of ADR was also observed with the resistant cells, whereas glucose markedly inhibited 2,4-dinitrophenol-stimulated uptake of ADR by the sensitive cells. Furthermore, in sensitive and resistant cells preloaded with ADR and DAU, efflux of the drugs was inhibited by the addition of 2,4-dinitrophenol. These results suggest that there is an active outward transport mechanism for anthracyclines in P388 leukemia cells and that enhanced activity of this efflux process renders cells highly resistant to the cytostatic and cytotoxic effects of ADR and DAU.

Animals↗
PubMed1979

Immunotherapeutic response of concanavalin A-bound L1210 vaccine enhanced by a streptococcal immunopotentiator, OK-432.

Immunotherapeutic response to concanavalin A (Con A)-bound L1210 murine leukemic vaccine and immunopotentiators was examined in histocompatible animals bearing a small burden L1210 leukemic cells. When combined with Con A-bound vaccine, a streptococcal immunopotentiator, OK-432 (NSC B116209), prepared from Streptococcus pyogenes, was potent in antitumor therapy and resulted in a number of cured animals. Administration of either Con-A-bound vaccine or OK-432 alone did not produce any beneficial effect on leukemic animals. The enhanced therapeutic response was dependent on the effectiveness of the dose and timing of the administration of OK-432 when given after vaccination. Combined modality of Con A-bound L1210 vaccine and OK-432 was not effective in animals bearing P388 murine leukemic cells, which indicates specificity of therapeutic response. In enhancing the therapeutic potency of Con A-bound leukemia vaccine, pyran copolymer (NSC 46015) was as effective as OK-432, whereas Bacillus Calmette-Guérin and Corynebacterium parvum were far less effective. When combined with OK-432, therapeutic response to Con A-bound L1210 vaccine was much greater than response to glutaraldehyde-, mitomycin C-, or Vibrio cholerae neuraminidase-treated L1210 vaccine.

Animals↗
PubMed1979

[Cerebral infarction due to vasospasm following intracranial aneurysm rupture (author's transl)].

We have made an investigation of the 827 cases of ruptured saccular cerebral aneurysms operated on and 151 of them presented infarction attacks thought to be due to vasospasm brought about by aneurysm rupture. Based upon symptoms, angiography and surgical findings, an analysis was made of their age, sex and aneurysm location so related to incidence of infarction, period from the initial or last rupturing until time of infarction, indication of vasospasms from angiographical findings, and symptoms of infarction. Infarction occurs only between the fourth and fifteenth days following the last bleeding and in this period there was a high incidence of rebleeding, so that the current conception of reattack following cerebral aneurysm rupture must be updated in light of the fact that the therapy for rerupture and the therapy for infarction due to vasospasm are completely different.

Adult↗
PubMed1979

Potentiation of L1210 murine leukemia vaccine in vivo by levamisole.

Intraperitoneal inoculation of either levamisole or 2 x 10(6) cells of concanavalin-A (Con-A)-bound L1210 leukemia vaccine produced no cured mice after subsequent ip inoculation of 10(3) live L1210 cells. Combined inocluation of levamisole and Con-A-bound vaccine produced about 20% cure incidence but no prolongation of life span of tumor-bearing mice after inoculation of live L1210 cells. Combined inoculation of levamisole and Con A-free vaccine did not induce detectable immune resistance in mice. These results suggest that levamisole enhanced host response to cell-bound Con-A associated with immunogenic potency of the vaccine. Levamisole given intravenously and orally was as effective as that inoculated intraperitoneally in enhancing the induction of resistance in mice by Con-A-bound vaccine. Dose of levamisole was very critical for this enhancement, being effective at 0.38 mg/kg but not either at 0.75 or 0.19 mg/kg. Furthermore, levamisole restored immune resistance induced by a larger inoculum of Con-A-bound vaccine cells (10(7)) and impaired by cyclophosphamide.

Adjuvants, Immunologic↗
PubMed1978

Chronopharmacological study of neuroleptics. II. Circadian susceptibility rhythm to chlorpromazine.

In order to study differences in the effect of the neuroleptics due to time of administration, rats were administered chlorpromazine (CPZ) in a variety of combinations of dose and time and the sedation period was measured. There was daily fluctuation in the sedative effect and the pattern of fluctuation differed according to dosage. A similar study under the condition of reversed light and dark gave a reversed curve of the daily fluctuation, showing that the rhythm of light and dark controls the fluctuation externally. In an attempt to elucidate the mechanism of these phenomena, CPZ was administered at two different times, between which there was a significant difference in the sedation period, and time-course changes in plasma and brain concentration of the drug and its metabolites were measured. No difference was found. These results are interpreted as indicating that the phenomena could arise at the level of amine-receptor activity in the brain. In addidtion, daily fluctuation due to time of administration was noted in lethality.

Animals↗
PubMed1978

Synthetic analogs of antitumor drugs under development in Japan.

Synthetic studies on new antitumor drugs in Japan are mainly oriented toward analogs of known active structures. In the nitrosourea area ACNU, a pyrimidine analog of CCNU, is currently under clinical investigation and has myelosuppression as a side effect Nitrosoureas with a sugar moiety are of great interest and two compounds called GANU and MCNU are now ready for phase I study in Japan. Among new alkylating agents are included a series of bis-methanesulfonate of aminoglycols, an analog of cyclophosphamide called 4-hydroperoxy-cyclophosphamide, and aziridine derivatives which include the now commercially available carbazilquinone. In the antimetabolite field cyclocytidine is an analog of arabinosyl cytosine which has been extensively studied. A newer analog called N4-behenoyl-cytosine arabinoside is now being studied experimentally. In the fluorinated pyrimidine area Ftorafur has been extensively studied and a new compound FD-1 is of interest.

Alkylating Agents↗