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Biomedical subjects

I Tanaka

Publications and source records attributed to I Tanaka.

At least 433 records · Page 24Linked to original sources
PubMed1987

[The inhaled effects of fenitrothion powder on blood cholinesterase in rats].

Effects of fenitrothion (Sumithion) powder on red cell acetylcholinesterase (AChE) and plasma cholinesterase (PChE) were studied in vitro and in vivo. Experiments in vitro revealed that fenitrothion has almost the same potency to inhibit AChE (in pre-washed red cell membrane) and PChE. Rats (Wistar, male) were exposed to fenitrothion powder for 4 hours using a new apparatus which can generate powder constantly over a long period. In this experiment, however, no apparent suppression of AChE was found while PChE was markedly inhibited. This inhibition persisted for 3 days after the exposure. This discrepancy was interpreted to be due to the inevitable procedure in preparing red cell specimens, i.e., washing of the red cells. After acute exposure in vivo, fenitrothion appears to be easily removed from the red cells by washing. Thus, PChE, rather than AChE, seems to be a good indicator of an acute exposure to fenitrothion powder in vivo.

Animals↗
PubMed1987

In vitro characterization of various heat-treated prothrombin complex concentrates (PCC).

All of 6 heat-treated prothrombin complex concentrates (PCC) tested contained adequate levels of factor IX but factor VII content was low. Levels of factors II, X, protein C and protein S were variable and antigen levels were always greater than those of functional activities. On crossed-immunoelectrophoresis factor IX showed variable anodal shift in all concentrates tested and in some activated factor IX was demonstrated by immunoblotting technique. These findings suggested some activation and/or denaturation during production and/or heating. Modest amount of factor VIII clotting activity by solid-phase amidolytic method and of factor VIII antigen was demonstrated in some concentrates but none contained more than a trace factor VIII inhibitor bypassing activity. The results suggested that heat-treated PCC should provide safe therapeutic products for hemophilia B.

Blood Coagulation Factors↗
PubMed1987

[Analysis of urinary metabolites of rats exposed to ethylene oxide].

Urinary metabolites of rats exposed to ethylene oxide(EO) were analyzed by gas chromatography-mass spectrometry(GC/MS). Male Wister rats(220-240 g) were exposed to EO for 6 hours. The urine was collected during 18 hours after the exposure and extracted with ethyl acetate. For the water-soluble metabolites, ethanol was added to the urine centrifuged and the supernatant fraction was evaporated to dryness. The residue of the extract was methylated with diazomethane and trimethylsilylated with bis(trimethylsilyl)trifluoroacetamide. Ethylene glycol, 2-hydroxymercapturic acid, 2-methylthioethanol and 2-mercaptoethanol were identified as the metabolites of EO. These results suggest that the inhaled EO was hydrolyzed to ethylene glycol, and conjugated with glutathion to form the mercapturic acid and methylthio metabolite.

Animals↗
PubMed1987

Estimation of breakthrough time on activated carbon fixed bed adsorbers for multicomponent organic solvent vapors.

The estimation of breakthrough time for multicomponent organic solvent vapors on activated carbon fixed beds is significantly complicated and difficult. This paper describes a simple estimation method of breakthrough time for the first component (foremost breakthrough component) in two- or three-component organic solvent vapors on an activated carbon fixed bed. The breakthrough time for the first component was expressed by the harmonic mean value of the breakthrough times in each pure component. Estimated breakthrough times were compared with the experimental ones.

Adsorption↗
PubMed1987

Angiosarcoma of the scalp: report of two cases with fatal pulmonary complications and a review of Japanese autopsy registry data.

Two cases of angiosarcoma of the scalp were reported. The patients were elderly men and died from pulmonary complications, including pneumothorax, pulmonary haemorrhage and pneumonia, associated with metastatic tumours in the lungs. The data recorded from 95 autopsies of patients with angiosarcoma in Japan during 1980-1984 were analyzed. According to the anatomical distribution of the primary tumour, the patients could be subdivided into a scalp group and non-scalp group. In both groups, the most common metastatic site was the lung. The patients of the scalp group had more frequent pulmonary complications such as pneumonia, haemothorax, atelectasis and pneumothorax, when compared with the patients of the non-scalp group. In particular, pneumothorax was observed only in the patients of angiosarcoma of the scalp. The results indicate that angiosarcoma of the scalp tends to metastasize to the lung, especially to the subpleural or surface pleural area and these metastatic tumours are prone to necrosis, causing characteristic pulmonary complications.

Aged↗
PubMed1987

Effect of azelastine on the release and action of leukotriene C4 and D4.

The effect of azelastine on the release of leukotriene C4 and D4 (LTC4 and LTD4), and the antagonistic action of the drug against the leukotrienes were determined by using in vitro tests and compared with those of ketotifen and chlorpheniramine. Azelastine inhibited LTC4 and LTD4 release from guinea pig lung fragments passively sensitized with homologous anti-ovalbumin IgGl-b antibody. The 50% inhibitory concentration (IC50) of azelastine was 6.4 X 10(-5) M for a 15-min preincubation or 4.7 X 10(-5) M for a 30-min preincubation. Ketotifen and chlorpheniramine were inhibitory only at the highest concentration tested (3 X 10(-4) M), giving inhibitions of 35.6 and 21.3%, respectively. Azelastine also inhibited calcium ionophore A23187-induced release of leukotrienes from human polymorphonuclear leukocytes; the IC50 values were 3.6 X 10(-5) M for 15 min and 2.3 X 10(-6) M for 30 min of preincubation. Ketotifen and chlorpheniramine were inhibitory only after a 30-min preincubation, with IC50 values of 2.1 X 10(-5) and 5.9 X 10(-5) M, respectively. The potent inhibition by azelastine might be partly a result of the inhibition of 5-lipoxygenase, since 5-hydroxyeicosatetraenoic acid formation in rat basophilic leukemia cell homogenate was inhibited by azelastine. Pretreatment of guinea pig ileum with azelastine antagonized LTC4- and LTD4-induced contraction of the ileum with IC50 values of 7.0 X 10(-6) and 1.1 X 10(-5) M, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Structure and physiological actions of rat atrial natriuretic factor.

Natriuretic substances were purified from rat atrium (atrial natriuretic factor, ANF) and were shown to be identical with the inhibitor of norepinephrine-induced contraction of smooth muscle. Four native forms were isolated and their amino acid sequences were determined. The presence of a high-molecular-weight prohormone was shown. Complementary DNA (cDNA) encoding for the precursor was cloned and used to deduce the amino acid sequence of the prohormone. Genomic DNA for ANF was cloned and two introns were found. Several ANF peptides were synthesized. Structure-function studies showed that the ring structure was essential for the activity. Antibodies produced against the synthetic 25-amino acid residue ANF were used to develop a radioimmunoassay. The presence of ANF in rat plasma demonstrated that ANF is a circulating hormone. ANF was also found in the hypothalamus of rats. The ANF in plasma was found to be a low-molecular form, whereas that in atria and hypothalamus consisted of both the high-molecular-weight precursor and low-molecular-weight active ANF. The presence of messenger RNA for ANF was determined using ANF cDNA as a probe and was considered as evidence for ANF synthesis in the brain, atrium, and ventricles. ANF was shown to be released from the brain. ANF administered intracerebroventricularly was shown to inhibit angiotensin II and thirst-induced dipsogenesis. In vitro and in vivo experiments showed ANF inhibits release of vasopressin from posterior pituitary and renin from the kidneys. The hypotensive effect of ANF was examined at various doses.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1987

Demonstration of insulin-like growth factor I in human urine.

Immunoreactive and receptor-reactive insulin-like growth factor I (IGF-I) was demonstrated in human urine. Thirty percent of the IGF-I immunoreactivity in urine was free, and the remainder was a high mol wt form (approximately 43K). Urinary IGF-I was quantitated by RIA after extraction with octadecylsilyl silica cartridges (Sep-Pak C18 cartridge), a method that measures only free IGF-I. The mean urinary immunoreactive IGF-I levels in normal adults (n = 8) and patients with acromegaly (n = 10) or hypopituitarism (n = 9) were 72 +/- 7 (+/- SEM), 225 +/- 34, and 19 +/- 4 pg/mg creatinine, respectively; these mean values were significantly different from one another. The results indicate that IGF-I is present in human urine and that the quantity in urine is altered in patients with GH excess and deficiency.

Acromegaly↗
PubMed1987

[Study of mechanism and effect of sodium 5-hydroxydecanoate on experimental ischemic ventricular arrhythmia].

We investigated the effects of sodium 5-hydroxydecanoate (5-HD) on experimentally induced ischemic arrhythmia and its mechanisms of action by biochemical and electrophysiological techniques. 5-HD, at the single dose of 200 mg/kg (p.o.) or at the one week multiple doses of 3 to 100 mg/kg (p.o.), suppressed the incidence of ventricular fibrillation induced by coronary ligation in rats. 5-HD at the dose of 3 or 10 mg/kg (i.v.) elevated the ischemically decreased ventricular fibrillation threshold in the coronary ligated dogs. In isolated rat heart, 5-HD suppressed the K+ release from ischemic myocardium at the doses of 10(-5) to 10(-3) M. 5-HD at the dose of 10(-4) M decreased the open state probability of ATP regulated K+ channel in isolated myocardial cell of guinea pig. Contents of high-energy-phosphate compounds were markedly decreased in ischemic myocardium of rats, and they were not affected by 5-HD. These results demonstrate the efficacy of 5-HD against experimental ischemic ventricular arrhythmia. Its antiarrhythmic action may be attributed, at least in part, to the suppression of K+ release from ischemic myocardium by possibly inhibiting the ATP regulated K+ channel.

Animals↗
PubMed1987

Effects of stimulus intensity and duration on photoresponses of single rods in the frog retina.

Electrical responses to light flashes were recorded from single red rods in dark-adapted retinas of the bullfrog, Rana catesbeiana. When the flashes were less than or equal to 50 ms in duration, plots of the peak amplitude of the responses as a function of log stimulus intensity were found to be parallel, and the stimulus intensity and duration required to elicit criterion-amplitude responses showed a linear relation with a negative unit slope. Furthermore the waveforms of equal-amplitude responses to flashes of different intensities and durations were superimposable. With increases in the stimulus duration beyond 50 ms, however, the slopes of the response-log intensity curves for the higher stimulus intensities decreased, the slope of curves describing the intensity required to elicit criterion responses became less negative, and the responses of the rods decayed more slowly. These results indicate that within 50 ms after the onset of flash stimuli, the effect of incident photons summate linearly to evoke rod responses of certain sub-saturating amplitudes when assessed in terms of the peak response amplitude as well as the response waveform.

Action Potentials↗
PubMed1987

[An immunohistochemical study using a double staining method for regional lymph nodes in gastric cancer].

We have performed a double immunofluorescent staining of two monoclonal antibodies, obtained from gastric cancer patients, that were directed against lymphocyte surface antigens on the regional lymph nodes. Through this method we were able to identify the lymphoid cell subset in detail. As a result of our double staining, most OKT8+ lymphocytes were also found to be Leu 15- lymphocytes and these OKT8+ Leu 15- lymphocytes were regarded as being cytotoxic effector cells or precursors. A few OKT8+ Leu 15+ lymphocytes (suppressor T lymphocytes) were obtained. More Leu 3a+ Leu 8- lymphocytes (helper T lymphocytes) were observed than Leu 3a+ Leu 8- lymphocytes (suppressor inducer T lymphocytes). To investigate whether these T lymphocytes were activated, we used an OKT 9 monoclonal antibody directed against the transferrin receptor and an OKIa1 monoclonal antibody directed against the HLA-DR framework. Such double stained lymphocytes (activated T lymphocytes) were few.

Antibodies, Monoclonal↗