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Biomedical subjects

Y Hokama

Publications and source records attributed to Y Hokama.

At least 73 records · Page 4Linked to original sources
PubMed1984

The effects of aspirin and acetaminophen on tetrahymena pyriformis GL growth and macromolecular synthesis.

The effect of aspirin and acetaminophen on Tetrahymena pyriformis GL is examined in this study. The concentration of drug which inhibited T. pyriformis GL growth in 24 hours, indicated as IC50, was 200 micrograms/ml and 580 micrograms/ml for aspirin and acetaminophen, respectively. Macromolecular incorporation study showed that aspirin at 100 micrograms to 400 micrograms/ml had essentially no effect on all parameters examined. Acetaminophen had a significant (P less than 0.01) suppression of 14C-thymidine, 14C-uridine and 14C-acetate uptake, but no effect on 14C-amino acid uptake at concentrations from 400 micrograms to 1200 micrograms/ml. T. pyriformis GL is a useful eukaryocytic single cell organism for drug action study.

Acetaminophen↗
PubMed1984

[Immunochemotherapy of human gliomas transplanted into nude mice].

In the first part of this paper, various chemotherapies were performed against oligodendrogliomas subcutaneously transplanted in to nude mice. Vincristine (VCR), adriamycin, and 1000 rads irradiation were effective against this tumors. Concerning these two drugs, dose response effect was observed. And the effect of 1 mg/kg injection of VCR roughly corresponded to that of five weekly injections of 0.2 mg/kg. In the second part of this experiment, single or combined effects of VCR and immunotherapeutic agents including OK-432 (OK), PSK, and recombinant leucocytic interferon (IFN) were examined. Two glioma lines including oligodendroglioma and glioblastoma were used. Following results were obtained from this experiment: 1) Effect of OK and VCR against oligodendrogliomas were as follows: control less than OK local injection (Local) less than OK intraperitoneal injection (IP); VCR; OK (IP X 2) less than VCR + OK(IP) less than VCR + OK (IP X 2). Effects of OK and VCR were expressed in order of their effects against glioblastomas: control less than VCR less than OK (IP); OK(IP X 2); OK(Local) less than VCR + OK (IP); VCR + OK (IP X 2). Effects of PSK and VCR against glioblastomas were as follows: control; PSK (Local) less than VCR less than VCR + PSK (Local) less than VCR + PSK (IP). Effects of IFN and VCR against oligodendrogliomas were as follows: control; IFN (IP) less than VCR less than IFN (Local) less than VCR + IFN (IP); VCR + IFN (Local). Effects of IFN and VCR against glioblastomas were as follows: control less than IFN (IP) less than VCR; IFN (Local); VCR + IFN (IP).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Inhibition of acetate incorporation into lipids by adriamycin.

Adriamycin (ADM) inhibits 14C-acetate incorporation into cardiomyocytes, with the ID50 being 0.9 microM. Incorporation into neutral lipids were inhibited except for cholesterol ester. Cholesterol and phospholipids demonstrated the strongest inhibition at 5 microM ADM.

Acetates↗
PubMed1984

Relationships of prostaglandin levels and natural killer (NK) cell cytotoxicity of mononuclear cells in cord blood.

Natural killer cell cytotoxicity of mononuclear cells and the corresponding plasma prostaglandins were examined in cord blood. Low NK cell cytotoxicity was demonstrated against three target cells: NK(K562), NK(HSV-1) and NK(Fs). Prostaglandins of the B, E and F series were examined and found to be higher than adult values. A significant correlation (p less than 0.05) between NK cell cytotoxicity and the prostaglandin F series was demonstrated.

Cytotoxicity, Immunologic↗
PubMed1983

A rapid enzyme-immunoassay for the detection of ciguatoxin in contaminated fish tissues.

An enzyme-immunoassay procedure for the detection of ciguatoxin has been developed using the sheep anti-ciguatoxin serum described earlier in the radioimmunoassay method for ciguatoxin. In the enzyme-immunoassay procedure, the sheep anti-ciguatoxin was coupled to horseradish peroxidase. Analyses of fish tissues showed that the enzyme-immunoassay procedure distinguished between clinically documented toxic and nontoxic tissues (P less than 0.001). Comparisons of the enzyme-immunoassay method with the radioimmunoassay for ciguatoxin and with a mouse bioassay demonstrated significant associations (P less than 0.001 and P less than 0.01, respectively). Preliminary studies showed that purified ciguatoxin inhibited the binding of sheep anti-ciguatoxin horseradish peroxidase to toxic fish tissues. Results suggest that the enzyme-immunoassay procedure may be valuable for routine direct assessment of ciguatoxin in fish tissues because of its practicality, sensitivity and specificity.

Animals↗
PubMed1983

Trigeminal pain caused by a parapontine epidermal cyst.

A case of trigeminal neuralgia caused by a parapontine epidermal cyst is reported. The trigeminal inlet zone at the pons was completely surrounded by the tumor. No vascular element was detected around the trigeminal nerve root. Neurological symptoms were completely normal except for typical tic douloureux. Pain was controlled initially by carbamazepine, later by radiofrequency trigeminal nerve coagulation, and finally by microsurgical decompression. Review of the literature suggested the importance of lesions of the middle fossa as another etiological factor. When surgery is performed by the posterior route, the possibility of overlooking these lesions may exist.

Aged↗
PubMed1983

Prostaglandin I2 (prostacyclin) formation in lung tissues of Swiss mice.

The indirect assessment of prostacyclin synthetase by analysis of prostaglandin I2 (PGI2) formation in lung tissues of fetal, newborn and adult Swiss mice was determined by in vitro platelet inhibition. PGI2 was synthesized in fetal, newborn and adult mice lung tissues. A progressive increase in PGI2 synthesis with increasing fetal age was shown. The 11 to 13 days fetal age samples gave PGI2 values of 12.0 and 20 ng per 50 mg lung tissue, respectively. These represented 20% and 33% of the adult mean value of 60 ng. Adult levels of PGI2 were attained in utero at fetal age of 16 days. It is suggested that because of its early appearance in fetal life in the lung tissue, prostacyclin synthetase is an important enzyme in prostaglandin metabolism in the ontogeny of the fetus.

Animals↗
PubMed1983

Prostacyclin (prostaglandin I2) formation in lung tissues of infants in sudden infant death syndrome (SIDS), non-SIDS and adults.

SIDS lung tissues elaborated significantly (p less than 0.01) lower PGI2 as compared with non-SIDS and adults. Significant differences (p less than 0.01) between SIDS and non-SIDS were especially shown at 2-4 months of age, 16.46 +/- 6.86 vs. 28.39 +/- 8.86 ng PGI2/50 mg of lung tissue, respectively, for SIDS and non-SIDS. A highly significant difference (p less than 0.001) was shown for SIDS (16.46 +/- 6.86 ng PGI2/50 mg lung tissue) when compared to adults (33.50 +/- 5.60 ng PGI2/50 mg lung tissue). It is suggested that there is defective maturation in the development of prostacyclin synthetase in lung tissues of SIDS infants.

Adult↗
PubMed1983

[Study on postoperative local chemotherapy of malignant brain tumors using ACNU and PSK].

There have been many attempts to treat patients with malignant brain tumors represented by glioblastomas using nitrosourea (NU) derivatives such as BCNU and CCNU but the clinical results are not so remarkable compared with previous reports concerning experimental studies. The reason for an efficacy of NU derivatives in brain tumors is considered to be its higher lipid solubility which makes the drug crossing the BBB easily. On the other hand, there is some evidence that higher lipid solubility did not guarantee NU to reach always to all portions of solid tumor after systemic administration. We have performed a chemotherapy of malignant brain tumors using ACNU for five years. This drug is not only lipid but also water-soluble in some grade; therefore, the drug is administrated intravascularly and locally with ease. Nine cases of malignant gliomas were treated with local chemotherapy employing ACNU and two cases of glioblastomas are surviving now over five years and about four years, respectively. From the anatomical standpoint of view, it is considered to be necessary for local chemotherapy of brain tumors to possess some pathognomonic characters such as cyst formations, central necrosis and localized cortico-meningeal adhesions, which are rather frequently found in malignant gliomas and are suspected also easily by CT examination preoperatively. A local chemotherapy in the present study has been performed using 10 to 50 mg of ACNU through an indwelling catheter inserted during operation. No general toxicity occurred in all patients except one, who experienced purulent meningitis after long-term drainage. In our study on concentration of ACNU, intracarotid injection resulted in higher concentration in brain tumor tissue than intravenous injection, but these concentration considered to be not high enough to suppress the tumor cell growth. On the other hand, the intracavitary concentration of ACNU at 24 hr after drug administration was high enough to suppress the tumor cell growth.

Adjuvants, Immunologic↗
PubMed1983

A potent naturally occurring low-molecular weight blastogenic inhibitory factor from edible black tree fungus.

Crude dialyzable extracts of Auricularia polytricha (black tree fungus) when added to lymphoprep-isolated blood mononuclear cells (PBL) stimulated with mitogens (PHA and PWM) showed significant inhibition of 3H-thymidine (3H-TdR) incorporation in vitro. Similar extracts of Agaricus biporus and Cortinellus shiitake demonstrated essentially no suppression of 3H-TdR uptake by PBL cells stimulated with PHA or PWM. A 50 micrograms/well (200 microliter) concentration of A. polytricha reduced 3H-TdR uptake of PHA stimulated PBL cells from different donors by 65.4 to 99.8% and similarly reduced 3H-TdR uptake of PWM stimulated PBL cells by 89.6 to 99.9%. Viability examination of PBL cells in RPMI medium with A. polytricha extract alone, mitogens alone, and mixtures of mitogens and extract for 72 hr at 37 degrees C showed per cent survivals as follows: medium alone, 93%; PWM, 91%; PHA, 77%; BTF extract (200 micrograms/ml), 57%; PWM + BTF extract, 47%, and PHA + BTF extract, 39%. Data presented show that Auricularia polytricha contained a low dalton potent blastogenic inhibitory factor(s).

Cell Survival↗
PubMed1982

Comparison of three different assays for the assessment of ciguatoxin in fish tissues: radioimmunoassay, mouse bioassay and in vitro guinea pig atrium assay.

Moderate correlation was shown between the following tests: RIA: mouse bioassay (r = 0.58); RIA: guinea pig atrium assay (r = 0.62); guinea pig atrium assay: mouse bioassay (r = 0.62). All three assay procedures showed good correlation when ciguatoxin was present in tissues in high concentrations. The results also suggest that more than one structurally related toxin may be present in the fish tissues.

Animals↗
PubMed1982

A growth-hormone--producing pituitary adenoma and an internal carotid artery aneurysm.

The case of a growth-hormone-producing pituitary adenoma which was in direct contact with a right internal carotid, medial-type aneurysm is reported. Direct clipping of the aneurysm and subcapsular removal of the adenoma were performed through a right frontotemporal craniotomy. The rarity of this direct contact and the cause of formation and enlargement of the aneurysm are discussed. The importance of angiography in cases of pituitary adenoma is stressed.

Acromegaly↗
PubMed1982

Changes in the FDP (fibrin and fibrinogen degradation products) value under mental and physical stress. II. Simultaneous observations of FDP and other indices of fatigue in persons under experimentally loaded stress.

We assumed the possibility of adopting FDP as an index of fatigue and carried out examinations upon various load conditions causing stress. For our observations other indices which are thought effective for fatigue evaluation, such as urine CA, flicker values, response time, Uchida's Kraepelin test, and examination of subjective symptoms recommended by the Japan Association of Industrial Health, were adopted at the same time. 1) Both mental and physical loads increased FDP values both in serum and in urine. 2) These changes in FDP values agreed comparatively well with the changes in CA by load. 3) The FDP value showed changes by load which was so light that it did not induce functional deterioration detectable by the response time or the flicker value which was considered to be one of effective physiological indices. 4) The extent or degree of subjective symptoms found by the survey agreed well with the changes in FDP values. Through above examinations, FDP values of serum and urine seem to be useful as an index of transient fatigue; especially they can well reflect mental fatigue which cannot be indicated well by other biochemical indices. Also FDP can well show individual characteristics, namely FDP indicates comparatively satisfactorily both individual sensitivity and specificity. Furthermore, this method does not require special techniques and examinations can be done simply.

Adult↗
PubMed1982

Presence of prostaglandins (PGs) in Tetrahymena pyriformis, GL and the effect of aspirin.

Tetrahymena pyriformis GL appears to require prostaglandins, either B, E or F series for growth, as demonstrated by the deleterious effect of aspirin. The latter inhibits prostaglandin synthetase (cyclooxygenase). Aspirin inhibited 50% growth of a 24 hr culture of T. pyriformis at a dose of approximately 200 micrograms/ml and completely inhibited at 600 micrograms/ml. Extraction with acid ethyl acetate: isopropanol solvent of 2.8 x 10(8) cells yielded 41.3 mg of lipid of which 62.8% and 34.5% were PGE2 and PGB, respectively. It is suggested that PGs are important for the growth of T. pyriformis and that the organism may be a useful source of natural PGs. Additionally, T. pyriformis may be useful in studies of the PGs pathway.

Animals↗
PubMed1982

[Postoperative treatment of malignant brain tumors with ACNU and PSK-particularly immunological follow-up research].

From the recent progress in immunological study, many authors have reported immune suppression in patients with malignant brain tumors. On the other hand, many factors are considered to influence the patterns of cellular and humoral immune parameters in patients with brain tumors, pre- and post-operatively. We treated the patients with malignant brain tumors using ACNU and PSK pre- and post-operatively, and 4 year survival rate was 35.3% (N: 17) in glioblastomas. We planned this time to measure immune parameters (Ig,lymprocyte number,Lyn and T-cell, Tn) pre- and post-operatively in order to study the immune states of patients. The results were as follows: The most significant finding was the elevated serum level of IgG in longterm survival of the patients with glioblastoma and the reduced one in patients with postoperative death. No other humoral immunocompetence existed except slightly reduced IgM level in the patients with death. Contrary to many previous studies, our research has suggested that humoral immune parameters are considered to be valuable to understand postoperative immune states of patients, and administration of PSK be effective as an immunomodulator.

Adult↗