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Biomedical subjects

T Okada

Publications and source records attributed to T Okada.

At least 433 records · Page 24Linked to original sources

Dobutamine stress echocardiography for detection of coronary artery stenosis in children with Kawasaki disease.

OBJECTIVES: This study was designed to assess the feasibility and diagnostic accuracy of dobutamine stress echocardiography for detection of coronary artery stenosis in children with Kawasaki disease. BACKGROUND: Dobutamine stress echocardiography is valuable as an alternative test for detection of coronary artery disease in adult patients; however, its usefulness for children has been demonstrated only in limited cases. METHODS: Dobutamine stress echocardiography (up to 30 microgram/kg body weight per min) was performed in 50 patients at the convalescent stage of Kawasaki disease, including 26 patients with coronary sequelae documented by previous coronary angiography (sequelae group, 3 to 15 years old) and 24 patients with normal coronary arteries documented by echocardiography (normal group, 7 to 16 years old), who underwent quantitative coronary angiography on a separate day. Left ventricular regional wall motion divided into 16 segments was assessed in relation to the extent of coronary artery disease. A positive test response was defined as a new or worsened wall motion abnormalities. RESULTS: Significant coronary artery disease (> or = 50% diameter stenosis of major vessels) was present in 21 patients in the sequelae group. There was no significant difference in the maximal dose of dobutamine between the sequelae and normal groups ([mean +/- SD] 22.4 +/- 5.1 vs. 24.2 +/- 2.5 microgram/kg per min). Heart rate and systolic blood pressure were significantly increased (p < 0.01) at maximal dose of dobutamine compared with values at rest in both groups; consequently, the rate-pressure product exceeded 20,000 in 20 (40%) of the 50 patients during dobutamine infusion. Ten patients had self-limiting side effects; however, there were no serious complications from stress-induced ischemia. New wall motion abnormalities corresponding to the extent of coronary artery disease were detected in 19 of 21 patients in the sequelae group, whereas no wall motion abnormalities were detected in the normal group. Thus, the sensitivity and specificity of dobutamine stress echocardiography for the detection of coronary artery disease were 90% and 100%, respectively. CONCLUSIONS: We conclude that dobutamine stress echocardiography is a safe and accurate diagnostic method for detection of coronary artery stenosis in Kawasaki disease. Moreover, this is a possible alternative method for patients unable to exercise adequately, even if they are small children.

Adolescent↗

Non-peptidic inhibitors of human neutrophil elastase: the design and synthesis of sulfonanilide-containing inhibitors.

A novel series of pivaloyloxy benzene derivatives has been identified as potent and selective human neutrophil elastase (HNE) inhibitors. Convergent syntheses were developed in order to identify the inhibitors which are intravenously effective in an animal model. A compound of particular interest is the sulfonanilide-containing analogues. Structure-activity relationships are discussed. Structural requirements for metabolic stabilization are also discussed.

Aniline Compounds↗

The 5'-flanking region of the human smooth muscle cell calponin gene contains a cis-acting domain for interaction with a methylated DNA-binding transcription repressor.

The human smooth muscle cell (SMC) calponin gene, which is composed of seven exons and six introns, spanning an approximately 11.2 kilobase (kb) genomic DNA, has been isolated and characterized by sequence analysis. As determined by primer extension mapping and rapid amplification of mRNA transcripts, a major transcription start site of the calponin gene is located at 101 base-pairs (bp) upstream of the ATG start codon. A striking feature of the 5'-flanking, 5'-untranslated, and amino-terminal protein coding regions is the presence of an Alu repetitive sequence and a stretch of DNA sequence identified using a methyl CpG-binding protein affinity column [Cross, S.H., Charlton, J.A., Nan, X., and Bird, A.P. (1994) Nature Genet, 6,236-244]. The results of this study provide a new insight into the molecular mechanism underlying regulation of SMC-lineage specific gene expression.

Base Composition↗

Intensity of halothane- and hypercapnia-induced cerebral hyperemia is strain-dependent in rats.

Cerebrovascular responses to physiologic and pharmacologic stimuli vary between laboratories using different strains of the same species. We tested whether the cerebral blood flow (CBF) response to 1% halothane or hypercapnia is strain-dependent in rats. Age-matched adult male (n = 14 of each strain) Wistar, Wistar-Kyoto (WKY), and spontaneously hypertensive rats (SHR) were anesthetized with pentobarbital and mechanically ventilated. Under baseline conditions blood flow to cerebrum (microspheres) in WKY (66 +/- 5 mL.min-1.100 g-1) was less than (P < 0.05) in Wistar (88 +/- 5 mL.min-1.100g-1) and SHR (83 +/- 5 mL.min-1.100 g-1). Blood flow to brainstem was greater (P < 0.05) in Wistar (106 +/- 8 mL. min-1.100 g-1) than in WKY (71 +/- 5 mL.min-1. 100 g-1) and SHR (84 +/- 4 mL.min-1.100 g-1). In the halothane protocol (n = 8 each strain), administration of 1% halothane, during normocapnia, increased blood flow to the cerebrum in WKY (64 +/- 6 to 120 +/- 12 mL.min-1.100 g-1, P < 0.05) and SHR (78 +/- 6 to 115 +/- 8 mL.min-1.100 g-1, P < 0.05) but not Wistar rats (88 +/- 8 to 102 +/- 5 mL.min-1.100 g-1, not significant). Discontinuing halothane caused blood flow to return to baseline values. In the hypercapnia protocol (n = 6 each strain), exposure to 3% CO2 (to achieve a PaCO2 of 50-55 mm Hg) and 6% CO2 (to achieve a PaCO2 of 60-70 mm Hg) caused blood flow to the cerebrum to increase in Wistar (87 +/- 11 to 112 +/- 15 to 162 +/- 23) to similar amount as observed in WKY (69 +/- 7 to 115 +/- 13 to 162 +/- 23 mL.min-1. 100 g-1) but less than that observed in SHR (89 +/- 7 to 174 +/- 24 to 237 +/- 28 mL.min-1.100 g-1). These data demonstrate that the cerebral hyperemic response to vasodilator stimuli is strain-dependent in rats.

Anesthetics, Inhalation↗

Brief reactive psychosis induced by sensitivity training: similarities between sensitivity training and brainwashing situations.

Sensitivity training (ST), which originated in the USA during the late 1940s, has been used as part of training seminars in Japanese corporations since the late 1950s. The possibility of negative psychiatric effects of ST, and especially its role in inducing psychiatric symptoms, is yet to be clarified. A case of a 41-year-old male company worker whose brief psychosis was induced by a sensitivity training seminar held by the company he worked for is presented. In reviewing the psychopathology of the case with records from the ST seminar, we found similarities between the patient's ST seminar and brainwashing situations. Specifically, the patient experienced severe conflict (of thought process) between his Christian beliefs and being labeled a coward at the seminar. We conclude that monitoring of the ST programs is crucial in order to ensure the psychological safety of ST participants in Japan.

Adult↗

Ultra-low-field magnetic resonance imaging in upper airways obstruction in sleep apnea syndrome.

The hypothesis that the sites of upper airways obstruction (UAO) are varied in a patient with obstructive sleep apnea syndrome (OSAS) among different sleep stages is studied. Four patients with OSAS underwent ultra-low-field magnetic resonance imaging (MRI) with a field strength of 0.064 Tesla provided real-time images and generated less noise and necessitated less strict magnetic isolation compared with conventional high-field MRI. After the fixed end-apneic sleep stage was determined, the polysomnogram was switched off and ultra-low-field MRI was commenced. The effects of continuous positive airway pressure (CPAP) on the upper airway patency in the deepest sleep stage obtained for each patient was assessed. Upper airway obstruction was found at the level of the palatopharynx (PP) at sleep onset extended to the glossopharynx (GP) during rapid eye movement (REM) sleep in two cases and during NREM sleep in one case. This combined PP and GP obstruction was observed from sleep onset and remained unchanged in one case. The patent upper airways were observed during treatment with CPAP during REM sleep in two patients and during stage two of NREM sleep in the other two patients. It can be concluded that the sites of UAO vary in a patient with OSAS in different sleep stages. The results also suggest the use of the ultra-low-field MRI in order to visualize the dynamic and real-time behaviors of the upper airways during sleep in patients with OSAS.

Adult↗

A case of possessive state with onset influenced by 'door-to-door' sales.

Recently in Japan, 'door-to-door sales' has become of concern because it has created numerous legal and social problems. In this paper, a 47 year old dissociative trance disorder case who presented with possession by God is discussed. Specific types of door-to-door sales is known to use superstition and folk beliefs as tools to lure customers. In this particular case, these religious factors seemed to have played an important role in the precipitation of the disorder and its presentation. In addition, the brain-washing environment observed in video lectures used in door-to-door sales seemed to play an important role in the development of the possessive state. We also performed social psychiatric analysis of the occurrence of the possessive state in a city area, which has been considered to develop within traditional culture. Phenomenological classification by one of the authors was useful for diagnosing underlying disorders in the possessive state.

Adult↗

Relationship between solvent inhalation and antisocial behavior: special emphasis on two types of violence seen in solvent abusers.

Organic solvent inhalation is a serious problem among youths in Japan. It induces physical and mental disorders, and is related closely to crime and delinquency. The relationship between solvent inhalation and antisocial behavior was investigated in 75 youths. The subjects were divided into three groups according to the level of violent behavior and the time of appearance: a non-violent group, a late-onset group (violence occurred after the start of inhalation) and an early-onset group (violence had occurred before the start of inhalation). Various parameters were compared among the groups. The late-onset group showed the following characteristics; (i) the frequency of inhalation was high, and many subjects experienced hallucinations and mood changes caused by inhalation; (ii) the family environment was characterized by conflict; and (iii) the subjects had strong psychological conflicts and showed dissociative coping with frustration. The violence, psychological conflict and dissociation in this group were found to be related to the inhalation, with familial conflict as a background. The violence in the early-onset group was considered to be the manifestation of a violent personality as the frequency of inhalation and the incidence of mental symptoms were both low. The subjects in this group showed weak psychological conflict and tended to be demanding of others when attempting to cope with frustration. Two types of violent behaviors in the teenagers who inhaled solvents were identified. The violence of solvent inhalers should be managed according to the type.

Administration, Inhalation↗

Evaluation of human skin irritation by carboxylic acids, alcohols, esters and aldehydes, with nitrocellulose-replica method and closed patch testing.

Closed patch testing and the nitrocellulose-replica method are performed as useful clinical methods for the evaluation of human skin irritation by cosmetics and topical medicaments. Comparison of the sensitivity between microscopic scoring by nitrocellulose-replica method and visual scoring by closed patch test in the detection of skin irritation, however, has not been well studied with statistical analysis. Here, we evaluated human skin irritation by carboxylic acids, alcohols, esters and aldehydes, with different chain length (C8-C18), using both methods. The results of closed patch testing showed that, although the score of skin irritation for carboxylic acids (C8, C12), alcohols (C8) and aldehydes (C8), tested at a concentration of 0.5 m-2.0 m, significantly increased with increasing concentration of the test compounds, ester compounds scarcely caused any irritation on the surface of the skin occluded. In addition, an increase of carbon chain length in the test compounds made it impossible to detect skin irritation. In contrast, the nitrocellulose-replica method could evaluate skin reactions against very weak irritants that gave no macroscopic alterations on the skin surface in the closed patch test. However, the scoring system is somewhat subjective and should be improved to make the analysis more objective.

Adult↗

A case of Guillain-Barré syndrome accompanied by sympathetic overactivity and hypertensive encephalopathy.

Hypertension has often been observed in patients with Guillain-Barré syndrome, and various underlying mechanisms have been implicated. We report the case of a child with the Guillain-Barré syndrome whose hypertension was associated with increases in both renin activity and circulating catecholamines. This case also appeared to be complicated by hypertensive encephalopathy. Following administration of intravenous regitine, a blood pressure change was observed and cardiac performance was assessed by two-dimensional echocardiography. Results indicated that increased total peripheral resistance may have been responsible for the symptoms and the hypertension. The hypertension was effectively managed by nifedipine, captopril and prazosin without the need for beta-blockade.

Child, Preschool↗

Superoxide and nitroglycerin stimulate release of PGF2 alpha and TxA2 in isolated rat heart.

The aim of this study was to investigate the effects of nitroglycerin (NTG), a nitric oxide (NO) donor used as a vasodilating agent, on prostanoid [e.g., prostaglandin (PG)] release in the O2(-)-pretreated rat heart. Perfusion of O2-, generated by a xanthine oxidase-purine coupling, caused elevation (P < 0.05) of the coronary perfusion pressure (CPP) after 20 min (from 57.1 +/- 3.9 during the control period to 72.2 +/- 3.9 mmHg, P < 0.05). O2- caused increased release of PGF2 alpha from 3.6 +/- 0.7 to 20.6 +/- 4.4 pmol.min-1.g-1 and of thromboxane A2 (TxA2) from 2.4 +/- 0.4 to 9.6 +/- 1.6 pmol.min-1.g-1 (P < 0.001) with no significant changes in PGE2 and PGI2 release. During the 20-min washout of O2- from the heart with normal Krebs solution, release of PGF2 alpha and TxA2 decreased to 8.7 +/- 1.4 and 6.3 +/- 1.7 pmol.min-1.g-1, respectively, and the release of PGE2 and PGI2 markedly increased from 11.1 +/- 2.9 to 25.4 +/- 3.6 and 157.2 +/- 16.4 to 413.2 +/- 41.4 pmol.min-1.g-1, respectively (P < 0.05), without lowering the elevated CPP. Administration of 4 microM NTG during the washout period paradoxically augmented the elevated CPP to 133.3 +/- 0.6% and was associated with a doubling (P < 0.05) of PGF2 alpha and TxA2 release with no significant changes in PGE2 and PGI2 release. The NTG-induced CPP elevation was inhibited (P < 0.05) by indomethacin, a cyclooxygenase inhibitor, or ONO-3708, a TxA2 receptor blocker, whereas arachidonic acid, a substrate for PG synthesis, augmented the CPP elevation. These results indicate that NTG stimulates the synthesis of vasoconstrictive PG in the O2(-)-pretreated rat heart, inducing a paradoxical elevation in CPP.

Animals↗

ETA and ETB receptors cooperate in DNA synthesis via opposing regulations of cAMP in human lung cell line.

We investigated the contribution of endothelin type A (ETA) and ETB receptors on ET-induced DNA synthesis in CCD-18Lu cells, a human lung cell line possessing both ETA and ETB (ETA/ETB ratio: 9:1). ET-1 (0.05-2 nM) potently induced [3H]thymidine incorporation by 2- to 14-fold over the basal level. An ETA-selective antagonist, FR139317, inhibited 0.2 nM ET-1-induced DNA synthesis dose dependently, showing complete inhibition at 1 microM. ET-3 was inactive up to 2 nM. In contrast, ETB-selective antagonists, 100 nM of BQ-788 or IRL 2500, partially (30-60%) inhibited 0.2 nM ET-1-induced DNA synthesis. Stimulation of either ETA or ETB evoked the increases in intracellular Ca2+ concentration ([Ca2+]i). ETB-mediated but not ET-1-induced [Ca2+]i increase was pertussis toxin (PTX) sensitive. Adenosine 3',5'-cyclic monophosphate (cAMP) formation via ETA was observed in PTX-treated cells, whereas the inhibition of isoproterenol-stimulated cAMP formation via ETB was observed in PTX-untreated cells. Like the ETB-selective antagonists, PTX treatment or dibutyryl cAMP partially (50-70%) inhibited ET-1-induced DNA synthesis. These data suggest that 1) ET-1 induces DNA synthesis predominantly through ETA, via PTX-insensitive G protein; 2) ETA-mediated cAMP formation inhibits DNA synthesis; and 3) stimulation of ETB coupling to Gi protein modulates ETA-mediated DNA synthesis by inhibiting cAMP formation.

Cell Division↗

Abnormalities in behavior, learning ability, and the cholinergic system induced by long-term ultraviolet A irradiation of mice.

Behavioral abnormalities, jumping reaction, increase in spontaneous activity abnormal violence, and lethargy were observed in long-term ultraviolet A (UVA)-irradiated hairy male Crj:CD-1 mice. The learning ability of 6- and 12-months UVA-irradiated mice was significantly reduced compared to un-irradiated age-matched mice. Acetylcholine levels, acetylcholinesterase and choline acetyltransferase activities in the whole brains were decreased in both of 6- and 12-month irradiated mice. Only 1 of 6 mice irradiated for 12 months was histologically observed to have a drastic loss of bilateral hippocampal pyramidal cells in the CA1 field of Ammon's horn.

Animals↗

Serum tumor necrosis factor in mesangial IgA glomerulonephritis with macroscopic hematuria in children.

Tumor necrosis factor (TNF)-alpha and interferon (INF)-gamma levels were measured in the sera obtained from 29 patients with IgA glomerulonephritis (IgA GN), 8 patients with minimal change nephrotic syndrome (MCNS) and 12 patients with upper respiratory tract infection (URI) without renal diseases in children. The serum TNF-alpha level of IgA GN was 123.0 +/- 175.4 pg/ml, MCNS was 4.9 +/- 4.0 pg/ml and URI was 10.5 +/- 4.5 pg/ml respectively. The serum TNF-alpha level of IgA GN was significantly higher than those of MCNS and URI. The serum TNF-alpha level of URI was on the high trend compared with that of MCNS, but was not statistically significant. Although the TNF-alpha level was related to mesangial cell proliferation in patients with IgA GN, it was unrelated to the grade of mesangial matrix expansion and magnitude of proteinuria. In 17 patients with IgA GN having macroscopic hematuria, the serum TNF-alpha level was 190.5 +/- 201.6 pg/ml, and in other IgA GN patients with microscopic hematuria it was 37.4 +/- 75.7 pg/ml. The serum TNF-alpha level of IgA GN with macroscopic hematuria was significantly higher than that with microscopic hematuria. In 6 patients with IgA GN with macroscopic hematuria, the serum TNF-alpha level was significantly decreased after macroscopic hematuria disappeared. The mean serum IFN-gamma level of IgA GN was 0.3 +/- 0.6 IU/ml, and MCNS was not detectable. Although the serum IFN-gamma level was related to mesangial cell proliferation in patients with IgA GN, it was unrelated to magnitude of proteinuria, the grade of mesangial matrix expansion and also the presence or absence of macroscopic hematuria. We suggest that macroscopic hematuria of IgA GN was closely related to the serum TNF-alpha level.

Adolescent↗