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Biomedical subjects

Y Sakaguchi

Publications and source records attributed to Y Sakaguchi.

At least 91 records · Page 5Linked to original sources
PubMed1993

Effect of hyperthermia on the activity of 1-[(4'-hydroxy-2'-butenoxy)methyl]-2-nitroimidazole, which is cytotoxic to hypoxic cells.

The effect on EMT6/KU cells of a newly synthesized hypoxic cell sensitizer, 1-[(4'-hydroxy-2'-butenoxy)methyl]-2-nitroimidazole (RK28), combined with heat was determined in vitro under conditions of hypoxia. As compared with aerobic conditions, hypoxia produced a 1.30-fold increase in the cytotoxicity of the drug for mouse mammary EMT6/KU cells induced by 1 h heat treatment at 43 degrees C in medium with a normal pH. Hypoxia also reduced the surviving fraction of cells treated with both RK28 alone for 2 h and the same concentrations of RK28 and heat (43 degrees C) in combination. Those enhancement ratios corresponded to a 20.3- and > 345-fold increase, respectively. Moreover, concomitant treatment with RK28 and heat greatly inhibited the clonogenic activity of the EMT6/KU cells under conditions of in vitro hypoxia and in all experimental groups; there was a statistically significant difference in the time-response curves (P < 0.05). As hypoxic cells in a solid tumor are resistant to various anticancer drugs, RK28 combined with hyperthermia deserves further study for possible clinical applications.

Animals↗
PubMed1993

Autoimmunity during alpha-interferon therapy for chronic hepatitis C.

One hundred twenty-five patients with chronic hepatitis C were treated with natural IFN alpha or recombinant IFN alpha-2a, daily doses of 3 MU or 9 MU, respectively. IFNs were given 6 times a week for the first 2 weeks followed by thrice weekly administration for 12 weeks or more. ANA, TMA, AMA and anti-DNA antibody newly developed in 8, 1, 2 and 1 patient, respectively. Furthermore, we encountered some cases in which underlying autoimmune disorders were thought to be exacerbated by IFNs. It is important to pay sufficient attention to the development of autoimmune diseases in IFN therapy for chronic hepatitis C.

Adult↗
PubMed1993

Rationale for preoperative screening of anti-HCV antibody.

We investigated the incidence of the anti-HCV antibody and associated factors in 1,031 surgical patients who had received blood transfusion during or after operation from October 1988 to April 1991, at Kyushu University Hospital. One hundred fifteen patients (11.2%) were anti-HCV positive. Sixty of the 219 patients (27.%) with a history of transfusion were positive, as were 55 of 812 (6.8%) without it. Patients aged under 40 showed a 0.6% positive rate (1 of 175) as did 8.5% (54 of 637) of those 40 and over in the no transfusion history group. Among the 637 patients without transfusion histories and aged over 40, patients with preoperative maximum ALT value over 36 IU. l(-1) had significantly higher positivity (16.0%, 29/181) than those with ALT values less than 35 IU. l(-1) (5.5%, 25/456, P < 0.01). The incidence of anti-HCV antibody in preoperative surgical patients in our hospital is ten times higher than that of donors. Anti-HCV are associated with transfusion, age, and liver dysfunction. Operating room personnel are at high risk because of contact with many HCV carrier patients.

Journal Article↗
PubMed1993

Acute accidental overdosage of haloperidol in children.

We report the details of an accidental overdosage of haloperidol in 24 children in one hospital in Kyushu, Japan. Evidence of acute toxicity included disturbances in consciousness (24/24), tremors in the extremities (16/24), an oculogyric or similar crisis (14/24), dysarthria (9/17), drooling (8/24), akathisia (6/20), hyperreflexia (6/24) and opisthotonos (3/24). Laboratory examinations revealed late-onset transient thrombocytosis (5/24), elevated AST and GPT (1/24) and abnormal ECG with prolonged QT interval in 2 of 8 children. We detected haloperidol in 11 of 18 children whose blood was specifically examined within four days after the final haloperidol administration. The maximum serum haloperidol level was 28.9 ng/ml. The mean half-life of haloperidol in the serum of five children (age range 2-10 years) was 18.6 +/- 12.2 h (mean +/- SD) (range 9.1-39.4 h).

Acute Disease↗
PubMed1993

Immunohistochemical localization of advanced glycosylation end products in coronary atheroma and cardiac tissue in diabetes mellitus.

Advanced glycosylation end products (AGEs) accumulate on long-lived extracellular matrix proteins and have been implicated in the micro- and macrovascular complications of diabetes mellitus. Within the arterial wall, AGE-modified proteins increase vascular permeability, inactivate nitric oxide activity, and induce the release of growth-promoting cytokines. Recently developed anti-AGE antibodies were used in an immunohistochemical analysis of coronary arteries obtained from type II diabetic and nondiabetic patients. High levels of AGE reactivity were observed within the atherosclerotic plaque present in vessels from selected patients with diabetes. Considered together with the pathological effects of AGEs on vascular wall homeostasis, these data support the role of advanced glycosylation in the rapidly progressive atherosclerosis associated with diabetes mellitus.

Aged↗
PubMed1993

[Potentiation of cytotoxicity of anticancer drugs by flavone acetic acid].

We used B 16 melanoma cells both in vitro and in vivo to determine whether Flavone acetic acid (FAA) can increase the cytotoxicity of mitomycin C (MMC) under normothermic and hyperthermic (HT) conditions. The significantly increased cytotoxicity of MMC combined with FAA and HT seems to be mainly related to activation of alkylating species under FAA mediated hypoxic condition.

Animals↗
PubMed1992

Effect of NaCl addition on nanosecond O2 escaping reaction of myoglobin: evidences for the transition of myoglobin dynamic structure at 20 degrees C.

We studied the nanosecond (ns) geminate O2 escape reaction from the protein interior of myoglobin (Mb) to the solvent phase in the temperature range of 5-40 degrees C containing 0-0.1 M NaCl. In the flash photolysis experiments, we found that both the rate constant, kout, and its Arrhenius plot changed upon the variation of the NaCl concentration. In particular, it was noteworthy that the Arrhenius plot of kout dramatically changed in its slope, keeping the break at 20 degrees C, upon the addition of NaCl, indicating that the thermodynamic parameters such as an enthalpy of activation (delta H not equal to) and an entropy of activation (delta S not equal to) are different between above and below 20 degrees C, and that they are further altered upon the NaCl addition to the sample solution. From these results, we suggested that the Mb dynamic structure in the ns geminate O2 escape reaction is sensitively regulated by the interaction of the protein surface and the salt. The present study also showed that an inconsistency of the Arrhenius plot of kout between Chatfield et al. ((1990) J. Am. Chem. Soc. 112, 4680-4687) and us ((1990) J. Biol. Chem. 265, 18823-18828) is probably due to the difference in the solution condition.

Myoglobin↗
PubMed1992

Flavone acetic acid increases the antitumor effect of hyperthermia in mice.

The combined effects of flavone acetic acid (FAA), a synthetic flavonoid, and hyperthermia on B16 melanoma cells were investigated. In vitro, FAA alone at concentrations below 100 micrograms/ml was not cytotoxic with a 60-min exposure at 37 degrees C. Hyperthermia at 43 degrees C for 60 min enhanced the cytotoxicity of FAA only at concentrations over 100 micrograms/ml. Inhibition of the growth of B16 melanoma solid tumor by FAA and/or hyperthermia was examined in vivo. FAA (100-200 mg/kg) inhibited tumor growth in a dose-dependent manner. The combined treatment of FAA (200 mg/kg) and hyperthermia (43 degrees C, 15 min) significantly inhibited tumor growth compared to a treatment of FAA or hyperthermia alone. The maximum antitumor effect of FAA combined with hperthermia was obtained when FAA was administered 2 or 4 h before heat. The significantly increased cytotoxicity of FAA combined with hyperthermia seems to relate to specific decreases in tumor blood flow, a reduction in tumor pH, and an increased tumor temperature, without altering pH in the normal tissues. This combined treatment of FAA and hyperthermia warrants further study for treating subjects with solid tumors.

Animals↗
PubMed1992

Signet ring cell carcinoma of the stomach.

Between 1965 and 1985, 51 of 1500 patients (3.4%) with gastric cancer who had gastric resection had signet ring cell gastric cancer. Patients with this form of cancer tended to be younger and female; the tumors were smaller and involved the stomach body, serosal invasion was less prominent, and lymph node metastases were less likely to be present. Early mucosal and submucosal cancer was present in 54.9% of the patients with the signet ring cell and in 24.6% with other types of gastric cancer. In 15.7% of patients with signet ring cell cancer, a noncurative resection was performed. The 5-year survival rate was 74.5% for patients with signet ring cell cancer and 52.4% for those with other types of gastric cancer (P less than 0.01). In patients with signet ring cell gastric cancer, the lesion is less extensive; thus, these patients probably can expect a longer survival time.

Adenocarcinoma, Mucinous↗
PubMed1992

5-Fluorouracil's cytotoxicity is enhanced both in vitro and in vivo by concomitant treatment with hyperthermia and dipyridamole.

We obtained evidence that the cytotoxic effect of 5-fluorouracil (5-FU) is augmented when the drug is given in combination with hyperthermia (HYP) and dipyridamole (DP). Nontoxic levels of DP enhanced the combined cytotoxicity of 5-FU and HYP against B16 melanoma and human tumor cells in vitro as measured by the succinate dehydrogenase inhibition (SDI) test. Growth of B16 melanoma that had been subcutaneously implanted into the feet of C57 BL mice was inhibited by treatment with the combinations of 5-FU and HYP, of 5-FU and DP, and of 5-FU, HYP and DP as compared with the administration of 5-FU alone. Treatment with HYP plus DP did not alter the body weight of mice that received 5-FU. The administration of DP plus HYP seemed to render the tumor cells more sensitive to 5-FU. The combination of 5-FU, HYP and DP shows promise for the treatment of patients suffering from malignant disease.

Animals↗
PubMed1992

Retrospective study of post-anesthetic mild liver disorder associated with inhalation anesthetics, halothane and enflurane.

The incidence of post-anesthetic mild liver disorder (PAMLD) was compared between 928 patients administered halothane and 1766 patients administered enflurane. They were selected from 19 504 surgical patients administered general anesthesia at Kyushu University Hospital over the past 6 years and 4 months. They had had normal liver function before operation and had no history of blood transfusion. Alanine aminotransferase (ALT) levels exceeding 70 IU. l(-1) within 180 days after operation were found in 226 patients in the halothane group (24.4%), and in 250 patients in the enflurane group (14.2%) ( P < 0.01). Both maximum ALT levels and duration of ALT elevation were higher and longer in the halothane group ( P < 0.01). These results suggest that, not only in the development of fulminant hepatitis but also in PAMLD, enflurane is less hepatotoxic than halothane.

Journal Article↗
PubMed1992

Continuous intraarterial infusion of prostaglandin E1 and heparin to extend and improve the survival of pedicled musculocutaneous flaps through unusual routes: a clinical preliminary report.

Sixteen pedicled musculocutaneous flaps (pectoralis major, 3; latissimus dorsi, 4; and transverse rectus abdominis musculocutaneous [TRAM], 9) received continuous intraarterial infusion of prostaglandin E1 (5 micrograms/k of flap per day) and heparin (100 to 200 U/cannula per day) for 14 days postoperatively to extend the flap or improve survival in a high-risk patient. Therapy was successful in 15 patients. To preserve the main arterial inflow to the flap, the infusion was administered via the lateral thoracic artery in the pectoralis major and a branch to the serratus anterior muscle in latissimus dorsi flaps in retrograde fashion, respectively, and was via both the ipsilateral deep epigastric artery and the contralateral superficial epigastric artery in TRAM flaps. This technique permits the use of a pedicled flap in some patients who would otherwise require a free flap.

Abdominal Muscles↗
PubMed1992

Adriamycin combined with hyperthermia and dipyridamole is cytotoxic both in vitro and in vivo.

The cytotoxicity of adriamycin (ADM) combined with hyperthermia (Hyp) and/or dipyridamole (DP) was investigated using B16 melanoma cells in vitro and in vivo. When ADM was combined with Hyp at 43 degrees C or DP in a dose of 5 microM or with both, drug cytotoxicity enhanced the inhibition of colony formation and cell growth, and the effect was maximal when Hyp and DP were combined. Incubation with DP alone for 24 h, following ADM exposure, enhanced the toxicity even further (p less than 0.01). Measurement of intracellular levels of ADM in the B16 melanoma cells showed that Hyp and DP increased accumulation of ADM, and that DP, but not Hyp, significantly suppressed the ADM excretion (p less than 0.05). Growth of B16 melanoma implanted into subcutaneous tissue of the foot of C57BL mice was inhibited to a greater extent by the combination treatment of ADM and DP, ADM and Hyp, and also that of ADM, Hyp and DP, compared to the findings in cases of ADM or Hyp alone. As this trimodality treatment is effective both in vitro and in vivo, further study on possible clinical advantage is warranted.

Animals↗
PubMed1992

Cytotoxicity of mitomycin C and carboquone combined with hyperthermia against hypoxic tumor cells in vitro.

Enhancement of the cytotoxicity of mitomycin C (MMC) and carboquone (CQ) by hypoxia at elevated temperature was examined using the SDI test of mouse Sarcoma 180 and Ehrlich cells and clonogenic assay of HeLa cells. When Sarcoma 180 and Ehrlich cells were incubated at 43 degrees C for 2-10 h, the hyperthermic effect was enhanced by hypoxia. The succinate dehydrogenase activity of the cells was reduced by hyperthermia to a greater extent in the presence of hypoxia (O2:5%) than under conditions of aeration (O2:20%). When the cells were exposed to various concentrations of MMC and CQ, under hypoxia, activity of the drugs was enhanced compared to the findings under conditions of aeration. The enhancement was prominent in case of drugs and hyperthermia combined. Clonogenicity of hypoxic HeLa cells was also reduced to a greater extent with this combination than in case of aerated cells. We tentatively speculate that hyperthermo-chemotherapy using MMC and CQ has a potential to attack selectively hypoxic cells present in a solid tumor.

Aerobiosis↗
PubMed1992

Comparison of in vitro anticancer chemosensitivity between human squamous cell carcinoma and adenocarcinoma.

The chemosensitivities of squamous cell carcinoma (SCC) tissues from the head and neck area were compared to findings of adenocarcinoma, mainly from digestive organs. The sensitivity of each tissue was determined using the in vitro succinate dehydrogenase (SD) inhibition test, which shares a common principle with the 3-(4,5-dimethyl-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. Tumor tissues were obtained at surgery or biopsy. Anticancer drugs tested were carboquone, Adriamycin, mitomycin C, cisplatin (CDDP), aclacinomycin A, 5-fluorouracil and 1-hexylcarbamoyl-5-fluorouracil with 10 times the peak plasma concentration, respectively. The means +/- standard deviations of SD activities in SCC tissues were significantly lower than those in adenocarcinoma tissues (p less than 0.001), and the sensitivity rates of SD activity in SCC tissues had a higher value than those in adenocarcinoma tissues (p less than 0.05), against each drug. Our study showed that CDDP-based combination regimens might be effective for SCC tissues. The chemosensitivity of each excised tissue should be tested, in order to prescribe sensitive, effective drugs for each patient.

Adenocarcinoma↗
PubMed1992

A pathologic and bacteriologic study on otitis media in swine.

A pathologic and bacteriologic study on otitis media in swine was performed on 237 swine, ranging in age from 1 day to 1 year. These 237 swine from eight selected farms were slaughtered due to unfavorable prognosis associated with clinical signs of illness. One hundred sixty-three (68.8%) of the 237 swine were found to be affected with otitis, though only a few swine showed clinical signs characteristic of the disease. One hundred fifty-one (63.7%), 53 (22.4%), and 39 (16.5%) had lesions in the middle, external, and internal ear, respectively. Of the 151 cases with otitis media, bilateral and unilateral infection accounted for 114 (75.5%) and 37 (24.5%), respectively. Only 5/53 swine with otitis externa and 6/39 swine with otitis interna failed to show otitis media. All swine with infection in the tympanic cavity had inflammatory lesions in the auditory tube. Examination of the swine grouped by age revealed that, regardless of age, incidence of otitis media was 50-70%. In swine younger than 1 month old, otitis media tended to center on the auditory tube, where a mild infiltration of neutrophils into the mucous membrane was frequent. Thereafter, otitis media increased in degree and extent with age. Forty (26.5%) of the 151 swine affected with otitis media were accompanied by a substantial amount of inflammatory exudate in the tympanic cavity and bulla. Purulent exudate was found in 20/40 (50%) swine. Severe otitis media prevailed in swine between 1 and 4 months of age, showing inspissation of a suppurative exudate in the tympanic cavity and lysis of the underlying osseous wall of the tympanic bulla with subsequent fibrosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Actinomyces↗