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Biomedical subjects

T Kawada

Publications and source records attributed to T Kawada.

At least 181 records · Page 10Linked to original sources
PubMed1995

Instantaneous change in sleep stage with noise of a passing truck.

The transient effects of passing truck noise on sleep polygraphs of 8 men were studied. The percentage of the sleep Stage 2 which changed from Stage 2 to Stage 1, waking or movement time, was calculated. The shallowing of REM sleep was identified when it had changed to other stages, and the shallow epoch percentage was calculated for the REM sleep. The percentage of shallow epochs for Stage 2 significantly increased against that of the control condition after exposure to noise but was not statistically significant for Stage REM. In conclusion, the shallowing or changes in the sleep Stage 2 or REM sleep with the passing truck noise might be observed at noise levels of less than 45 dBA or greater than 60 dBA, respectively.

Acoustic Stimulation↗
PubMed1994

Characterization of platelet activity in neuroblastoma.

A study was conducted to characterize the platelet aggregation induced by neuroblastoma tissue to investigate the mechanism of hypercoagulability in patients with neuroblastoma. The patients whose tumor tissues were examined had been shown clinically to have enhanced platelet activity. Platelet aggregation induced by neuroblastoma tissue extract was compared with that of other pediatric tumors. The effects of pretreatment with an antithrombin agent and prostacyclin (PGI2) on the platelet aggregation induced by tumor tissue extracts were also evaluated. Tissue extracts of 12 of 15 neuroblastomas, 3 of 3 Wilms' tumors, and 1 pheochromocytoma were demonstrated to have an activity that potentiated platelet aggregation in vitro. The platelet aggregation induced by tissue extracts of neuroblastomas and other tumor tissues was suppressed almost completely by pretreatment with a PGI2 analogue. The aggregation induced by neuroblastomas and the pheochromocytoma was also suppressed by pretreatment with an antithrombin agent, argatroban, whereas the aggregation induced by Wilms' tumors was not suppressed by this agent. These results suggest that (1) malignant tumors in children also have some chemical substances that sensitize platelet activity, such as those in adult cancers, and (2) thrombin is one of the mediators stimulating platelet aggregation in cases of neuroblastoma, although it is unlikely to be a contributing factor in other pediatric malignancies such as Wilms' tumor.

Antithrombins↗
PubMed1994

Effects of capsaicin analogs on adrenal catecholamine secretion in rats.

To assess the relationship among the structure, pungency and thermogenic action, a series of capsaicin analogs with saturated acyl moieties (heptanoyl to eicosanoyl vanillylamide) were synthesized. Pungency of the compounds and the thermogenic action, which was examined by the potential of the compounds (655 nmol/kg, i.v.) to enhance adrenal catecholamine secretion for 15 min in anesthetized rats, were compared. On the chain length of the acyl moieties of the analogs, nonanoyl to octadecanoyl vanillylamide caused strong adrenal catecholamine secretion, but heptanoyl vanillylamide and eicosanoyl vanillylamide caused weak or no response. Pungent analogs except heptanoyl vanillylamide and non-pungent analogs except eicosanoyl vanillylamide had strong potency to secrete adrenal catecholamine.

Adrenal Medulla↗
PubMed1994

The prevention of adipose differentiation of 3T3-L1 cells caused by retinoic acid is elicited through retinoic acid receptor alpha.

Retinoids, especially all-trans retinoic acid (RA), have been shown to inhibit the differentiation of preadipose cells. It is important to human health, especially to obesity, that the regulatory system for the differentiation of adipocytes is well defined. Previously, we have shown that retinoic acid receptor (RAR) gamma 2 gene expression is up-regulated by RA in 3T3-L1 preadipose cells. In this study, the RAR system was dissected and the RA-regulated function in 3T3-L1 cells was assigned to one given receptor. We used three synthetic retinoids; (1) Ro 41-5253, a selective RAR alpha antagonist, (2) Ch 55, an RAR alpha, beta and gamma agonist, and (3) Am 80, an RAR alpha and beta agonist, which has less affinity to RAR gamma. Ro 41-5253 reverted RA-induced inhibition of the differentiation of 3T3-L1 cells. However, there was no significant reversion in RA-induced RAR gamma mRNA level by treatment with Ro 41-5253. In the case of RAR agonists, both Am 80 and Ch 55 strongly inhibited the differentiation of 3T3-L1 cells. However, Am 80 weakly increased RAR gamma mRNA content less than did Ch 55. These findings suggest, that RAR alpha is involved in the prevention of adipose differentiation by RA in 3T3-L1 cells. Moreover, there seems no causal relationship between the prevention of adipose differentiation by RA and the up-regulation of RAR gamma 2 gene expression by RA in 3T3-L1 cells. We have shown the functional heterogeneity of RA action through different RARs in 3T3-L1 cells.

3T3 Cells↗
PubMed1994

Modification by LY 83583 and methylene blue of relaxation induced by nitric oxide, glyceryl trinitrate, sodium nitroprusside and atriopeptin in aortae of the rat, guinea-pig and rabbit.

1. The relaxation by nitroglycerin (GTN) and nitric oxide (NO) of aortic smooth muscles from rabbit and rat contracted by phenylephrine was inhibited by LY 83583 (LY) and methylene blue (MB) (the same applied to guinea-pig aorta), while the relaxation by SNP was not inhibited in rabbit. The relaxation by ANP was not inhibited. 2. All these agents produced concentration-dependent increases in cyclic GMP. While the increases by GTN and NO were inhibited by LY and MB, the increases by SNP were inhibited only in rat and those by ANP were not inhibited. 3. Thus, LY behaved essentially similar to MB, indicating that the substance is an inhibitor of activation of soluble guanylate cyclase by NO and NO-related vasodilators. It was assumed that, like MB, LY facilitated intracellular release of NO from SNP in rabbit.

Aminoquinolines↗
PubMed1994

Transient and all-night effects of passing truck noise on the number of sleep spindle.

Changes in the number of transient and all-night sleep spindles by traffic noise of 55 to 65 dB(A) were studied. The sleep parameters were the number of spindles per minute in stages 2, 3, and 4 (S2, S3, S4) and the total number of spindles divided by the total sleep time. A transient decrease in the number of spindles was recognized and after noise exposure, the number of spindles increased to near the pre-exposure level. Spindles were counted from S2, S3 and S4 for all-night sleep. The number of spindles in all-night sleep by noise exposure increased. The authors explain discrepancies in the results by a compensatory brain mechanism of sleep disturbance due to passing truck noise.

Adult↗
PubMed1994

Effects of regular health practices on subjective evaluation of health.

The effects of Breslow's seven health practices on health were examined. The Today Health Index (THI), a questionnaire for self-evaluation of physical and mental health, was applied to male workers of a private company as well as their wives. The subjects resided in the suburbs of Tokyo and the average ages of the males and females were 41.5 and 38.4 years, respectively. Statistical results were obtained using Mann-Whitney U-test, analysis of covariance, and Hayashi's quantification theory I. A statistically significant decrease in the THI scale scores among subjects observing six or more health practices when compared with those observing three or less was demonstrated in vague complaints and irritability in males, and in respiration in females. In males, the THI scale scores of vague complaints, respiration, and the mouth and anus significantly decreased by sleeping well. Those of irritability and irregularity of life decreased by not smoking and those of vague complaints and irritability decreased by not eating between meals. In females, the THI scale scores of vague complaints, eye and skin, and the mouth and anus significantly decreased by exercising regularly. Those of irregularity of life decreased by not smoking. Those of respiration decreased by good weight control. Those of respiration and the mouth and anus decreased by not eating between meals. Exercising regularly in females was a good predictor of vague complaints using multi-variate analysis adjusted for age. Subjective evaluation of health improved by Breslow's recommended health practices.

Adult↗
PubMed1994

Relationships between mean lead levels in the atmosphere and in blood from data published since 1977.

The authors attempted to confirm the reliability of the linear log-log model presented by Goldsmith and Hexter in 1967. The data used were from seven reports published since 1977, including that of the authors. The age of the subjects in these reports ranged from three to over 65 years. Various methods of air sampling and pre-treatment of collected particulate matter were employed. Lead was determined by atomic absorption spectrophotometry. The mean value of lead in the atmosphere ranged from 0.11 to 19 micrograms/m3. A regression line obtained from 13 pairs of averaged lead in the atmosphere and in blood was log(Pb-B) = 0.259 x log(Pb-A) + .243, and the Pearson's moment correlation coefficient between the logarithm of Pb-A and the logarithm of Pb-B was 0.839. These results were roughly the same as those of Goldsmith. This finding confirms the consistency of the association between Pb-A and Pb-B, which may be used to monitor atmospheric and blood lead quantitatively in those countries conducting a lead reduction program in gasoline.

Air Pollutants↗
PubMed1994

[Blood concentrations of thrombomodulin in patients with various diseases].

Concentrations of thrombomodulin in blood plasma were measured by a one-step sandwich enzyme immunoassay (EIA). The concentrations in normal healthy subjects were 9.9 +/- 2.9 ng/ml. The concentrations were found to be significantly higher in patients with SLE, RA and other collagen diseases in their active stages than at their non-active stages. The concentrations increased in patients with DIC, and significantly higher levels were observed when DIC was complicated by multiple organ failure. These findings indicate that plasma concentrations of thrombomodulin may be a useful parameter for vascular injuries caused by inflammatory processes or coagulation/fibrinolysis reactions.

Adult↗
PubMed1994

[Left heart bypass with the bio-medicus centrifugal pump by the use of an antithrombin agent, argatroban].

Seventeen adult patients who underwent surgery for the thoracic or thoracoabdominal aortic disease by the use of left heart bypass with the Bio-Pump were divided into untreated, low-dose heparin treated and argatroban treated groups so as to evaluate the effects of systemic infusion of a newly synthesized antithrombin agent, argatroban, for the prevention of platelet loss and consumption coagulopathy. ACT reached 150 to 250 seconds at doses 0.5-7.5 micrograms/kg/min of argatroban and maximum ACT prolongation was limited to around 250 seconds. ACT spontaneously recovered below 150 seconds within 60 minutes following the end of bypass during which no excessive blood loss developed. In argartoban group, platelet loss during and immediately after surgery was effectively prevented as compared to other groups with significance. Fibrinogen was also preserved to some extent by argatroban treatment without evidence of systemic embolization. Argatroban, as an antithrombotic agent, is worthy of further trial of clinical use in bypass with a centrifugal pump.

Adult↗
PubMed1994

[The usefulness of combined measurements of transcranial Doppler sonogram and somatosensory evoked potentials during hypothermic cardiopulmonary bypass].

Serial and simultaneous measurements of the blood flow velocity of the middle cerebral artery (MCA-V) by transcranial Doppler sonography (TCD) and somatosensory evoked potentials (SEP) were performed in 7 adult patients during hypothermic cardiopulmonary bypass (CPB). CPB was instituted by alpha-stat blood gas management until the rectal temperature stabilized at 24 to 28 degrees C and gas management was converted from alpha to pH-stat by adding 4-7% of CO2 gas into the oxygenator for 10 minutes. MCA-V during hypothermic CPB by alpha-stat management was identical with normothermic prebypass MCA-V. However it significantly increased after pH-stat conversion, suggesting that CO2 reactivity was preserved even in the hypothermic situation above 24 degrees C of body temperature. Latency of all wave components of SEP and central conduction time (CCT) prolonged and wave voltages decreased as the body temperature dropped and SEP waves almost completely recovered following the temperature resumed to the prebypass temperature. There were no significant changes developed in latency and wave forms of SEP by conversion of the blood gas management from alpha-stat to pH-stat. The combined technique of TCD and SEP for detecting the real time changes of cerebral blood flow and brain function is considered to be useful to minimize the brain damage during open heart surgery.

Blood Flow Velocity↗
PubMed1994

[Coronary artery bypass grafting for a patient with single coronary artery].

A 47-year-old man was admitted with suddenly developed chest pain. Coronary arteriography could not identify the right coronary orifice at the right coronary sinus. Left coronary arteriography revealed that the right coronary artery originated from a proximal segment of the left anterior descending artery with subtotal obstruction at the segment just distal to the bifurcation of the right and anterior descending arteries. Coronary artery bypass grafting to the middle segment of the left anterior descending artery was carried out with satisfactory result. To our knowledge, only seven cases with a diagnosis of single coronary artery who underwent coronary artery bypass grafting have been reported.

Coronary Angiography↗
PubMed1994

[Evaluation of combination chemotherapy for advanced gastric carcinoma as a neoadjuvant chemotherapy with CDDP, MMC, etoposide and 5'-DFUR].

Seven cases of nonresectable gastric carcinoma with lymph node metastasis were treated with combination chemotherapy [CDDP 75 mg/m2 i.v. day 1 (A method: Ccr > or = 50 ml/min) or 20 mg/m2 i.v. day 1, 2, 4, 5 (B method: Ccr < 50 ml/min), MMC 10 mg/m2 i.v. day 1, etoposide 50 mg/body i.v. day 3, 4, 5, 5'-DFUR 2,100 mg/body po 4 day/week] every 4 weeks as a neoadjuvant chemotherapy. After treatment, the size of the primary tumor was reduced in four of seven cases. The lymph nodes disappeared in one case and were reduced in size in four cases. Metastatic liver tumors were found in four cases. They disappeared in one case and the size was reduced in one of seven cases. One patient with renal dysfunction was treated with B method. However, renal dysfunction did not become worse. Five patients were operated after chemotherapy. Absolute curative resection was performed in three of them. The total rate of curative resection was 43% (3/7). Four patients were alive for 19 months after operation. The main side effects of this therapy were nausea, anorexia and bone marrow suppression, which, were found in all patients. These results suggest that this combination chemotherapy is as effective as neoadjuvant chemotherapy for advanced gastric carcinoma.

Aged↗
PubMed1993

Retinoic acid receptor gamma 2 gene expression is up-regulated by retinoic acid in 3T3-L1 preadipocytes.

Retinoids, especially all-trans retinoic acid (RA), have been shown to inhibit the differentiation of preadipose cells. In the present study, the expression of retinoic acid receptors (RAR alpha, beta and gamma) and retinoid X receptors (RXR alpha, beta and gamma) was examined by Northern blot analysis in rat adipose tissue and mouse 3T3-L1 adipose cells. The adipose tissue and/or 3T3-L1 cells expressed mRNAs for a number of nuclear retinoid receptors, including RAR alpha, beta and gamma, and RXR alpha, beta and gamma. RAR alpha, RAR gamma, RXR alpha and RXR beta mRNAs were abundant in adipose tissue and 3T3-L1 cells. RXR gamma mRNA was detected in adipose tissue but not in 3T3-L1 cells. Treatment of 3T3-L1 cells with 1 microM RA led to a 4-5-fold increase in the RAR gamma mRNA level, but only a trace amount of RAR beta mRNA was detected. RAR gamma mRNA expression was rapidly (within 2 h) induced by physiological concentrations of RA in a dose-dependent manner. The response of RAR gamma mRNA expression to RA was reversible; rapid disappearance of RAR gamma mRNA occurred on RA removal. In addition, the induction of RAR gamma expression did not require de novo protein synthesis, but was completely abolished by an inhibitor of RNA synthesis. Using RAR gamma 1 and gamma 2 isoform-specific probes, the patterns of RAR gamma 1 and gamma 2 mRNA expression in 3T3-L1 cells in the presence and absence of RA were examined. RAR gamma 1 mRNA was detected in 3T3-L1 cells but was not affected by RA treatment; however, RAR gamma 2 mRNA was strongly induced by RA.

3T3 Cells↗
PubMed1993

Vitamin D receptor gene expression is up-regulated by 1, 25-dihydroxyvitamin D3 in 3T3-L1 preadipocytes.

Vitamin D3, especially 1, 25-dihydroxyvitamin D3 (1, 25 (OH)2 D3), has been shown to inhibit the differentiation of preadipose cells. In the present study, the expression of vitamin D receptor (VDR) was examined by Northern blot analysis in rat adipose tissue and mouse 3T3-L1 adipose cells. The adipose tissue and 3T3-L1 cells expressed mRNA for VDR. Treatment of 3T3-L1 cells with 1 microM 1, 25 (OH)2 D3 led to a 4-5 fold increase in the VDR mRNA level. VDR mRNA expression was rapidly (within 4 hr) induced by physiological concentrations of 1,25 (OH)2 D3 in a dose-dependent manner. The induction of VDR expression did not require de novo protein synthesis but was completely abolished by an inhibitor of RNA synthesis.

3T3 Cells↗