PubMed Health⌕ Search

Biomedical subjects

T Toyooka

Publications and source records attributed to T Toyooka.

14 recordsLinked to original sources
PubMed2006

Inhibition of apoptosis by menadione on exposure to UVA.

Quinones are widely distributed in the environment, both as natural products and as pollutants. This paper reports that one of the simplest quinones, 2-methyl-1,4-naphthoquinone (menadione), effectively inhibited apoptosis in the presence of UVA. Menadione suppressed the apoptosis induced by serum depletion and cell detachment. This effect was significantly enhanced by UVA irradiation. An antioxidant, N-acetylcysteine, completely inhibited the antiapoptotic effects of both menadione itself and menadione plus UVA, and peroxidation of the cells after treatment was observed using a probe to detect the intracellular production of peroxides. By contrast, 2-hydroxy-1,4-naphtoquinone (lawsone) showed no antiapoptotic effect in the presence or absence of UVA. Lawsone is reported not to undergo the redox process that produces reactive oxygen species. These results indicated that intracellular peroxidation contributed to the antiapoptotic effects of both menadione itself and menadione plus UVA. Dysregulation of the apoptotic process is critical to carcinogenesis. The photosensitization of quinone compounds as it relates to the inhibition of apoptosis should be examined in the future.

Acetylcysteine↗
PubMed2006

Alteration of gap junction proteins (connexins) following lateral fluid percussion injury in rats.

Gap junctions are intercellular channels that mediate the cytoplasmic exchange of small hydrophilic molecules and are formed by a family of integral membrane proteins called connexins (Cxs). Cx43 is expressed predominantly in astrocytes, while Cx36 is expressed in neurons. In this study, we show alteration of Cx43 and Cx36 in the hippocampus after traumatic brain injury in rats. Adult male Sprague-Dawley rats were subjected to lateral fluid percussion injury of moderate severity. Brain coronal sections were used for immunohistochemistry with Cx43 and Cx36 antibodies. Cx43 immunoreactivity was increased in reactive astrocytes in the damaged hippocampus 24 hours after injury, and persisted for 72 hours. On the other hand, Cx36 immunoreactivity increased in CA3 neurons 1 hour after injury, and decreased later. These results indicate that gap junctions might participate in the pathophysiological process after traumatic brain injury.

Adaptation, Physiological↗
PubMed2003

Focal brain edema and natriuretic peptides in patients with subarachnoid hemorrhage.

Central salt wasting syndrome may be caused by pathological increases in serum natriuretic peptides after subarachnoid hemorrhage (SAH). However, it is unclear as to why the serum concentration of atrial natriuretic peptide (ANP) or brain natriuretic peptide (BNP) increases in the subacute phase of SAH. The present study was designed to assess the correlation between focal brain edema and serum concentration of ANP or BNP in patients with SAH. Focal brain edema was found in 8 SAH-patients and peaked between days 4 and 7 of SAH. The mean serum ANP and BNP levels in patients with focal brain edema were significantly higher than those in patients without focal brain edema between days 4 and 14 of SAH. These results suggest that focal brain edema might correlate with increased levels of ANP and BNP in the subacute phase of SAH.

Atrial Natriuretic Factor↗
PubMed2001

Depressive mood accompanies hypercholesterolemia in young Japanese adults.

Screening of young hypercholesterolemics is important because they are highly susceptible to atherosclerotic diseases. However, in some cases, serum cholesterol level may be elevated temporarily due to stress or other psychological factors. This study examined the effects of mood states on 'persistent' hypercholesterolemia in comparison with 'temporary' hypercholesterolemia among students entering a university. The subjects were 114 untreated first-year students aged 18 to 20 years old. All had been screened positive for hypercholesterolemia (serum total cholesterol > or = 220 mg/dl) upon enrolling in the university. Three months after the screening, they were divided into two groups according to the re-examined serum total cholesterol level; a persistent hypercholesterolemic group (n=41) with >220 mg/dl and a temporary hypercholesterolemic group (n=73) with <220 mg/dl. At that time, they completed the Profile of Mood States (POMS) with tension-anxiety, depression, anger-hostility, vigor, fatigue and confusion scales. The POMS depression scores and the female ratio were higher (both p<0.01) and body mass index was lower (p<0.05) in the persistent hypercholesterolemic subjects than in the temporary hypercholesterolemic subjects; the POMS depression scores were still higher (p<0.05) after controlling for the effects of gender, body mass index, and other POMS scales by multiple logistic regression analysis. Depressive mood appeared to relate to hypercholesterolemia when the university students were screened. Assessment of mood states may be important in screening young hypercholesterolemic patients.

Adolescent↗
PubMed2000

[Gene therapy--its present status and future direction].

Remarkable progress in molecular biology has succeeded in developing gene therapy that is applicable in patients with a poor prognosis. At the Annual Meeting of Japanese Pharmacological Society this spring, the symposium entitled "Gene therapy: its present status and future direction" was held and this produced fruitful results. The symposium covered the following five topics, introduction to gene therapy, ischemic diseases, intractable heart failure, metastatic long cancer, ADA deficiency, which were presented by Drs. Y. Kaneda, Osaka Univ.; M. Aoki, Osaka Univ.; T. Kawada, Niigata Univ.; T. Fujiwara, Okayama Univ. and Y. Sakiyama, Hokkaido Univ., respectively.

Adenosine Deaminase↗
PubMed1998

Separation of amino acid and peptide stereoisomers by nonionic micelle-mediated capillary electrophoresis after chiral derivatization.

Enantiomers of amino acids and peptides were derivatized with a fluorescent chiral reagent, 4-(3-isothiocyanatopyrrolidinl-yl)-7-nitro-2,1,3-benzoxadiazole [R-(-)- or S-(+)-NBD-PyNCS] and the resulting diastereomeric derivatives separated by capillary electrophoresis (CE). The CE running buffer consisted of 25 mM acetate buffer (pH 4) and 10 mM of the nonionic surfactant Triton X-100. The excitation maximum of NBD-PyNCS at 480 nm matches the major Ar-ion emission line at 488 nm allowing sensitive laser-induced fluorescence detection with limits of detection around 50 nM. D-Proline and D-aspartate spiked (at 10(-4) M and 10(-5) M concentrations, respectively) into complex biological matrices (rabbit serum and homogenate of Aplysia californica buccal ganglion) are detected without matrix interferences. This method has also been applied to the determination of D- and L-amino acid residues in peptides after acid hydrolysis. Results from the chiral analysis of the naturally-occurring peptide, gramicidin D, are shown.

Amino Acids↗
PubMed1996

[Survey on oral health of university students: examination on tooth conditions using panoramic X-ray films].

As an aid in instructions oral health care to university students, tooth conditions were examined using panoramic X-ray films. The materials were taken from 129 students of the University of Tokyo. The average age was 22 years 5 months. The results were as follows: 1. Lack of tooth was frequently found to be both maxillary and mandibular third molars. It was also occasionally found to be maxillary first premolars, mandibular lateral incisors, and mandibular second premolars. The average value for lack of tooth per individual was 0.9. 2. Root canal fillings were often found in mandibular first molars, maxillary central incisors, mandibular second molars and maxillary second premolars. The average value was 1.1. 3. Metal restorations were often made in first and second molars, especially in mandibular. The average value was 6.2. 4. As for maxillary third molar axis, the majority showed normal direction. In mandible, however, the normal direction was only found in 37.7% and the others showed troublesome axes. It seemed that careful attention should be given to the mandibular third molar conditions.

Adult↗
PubMed1991

Effects of atrial natriuretic peptide on endothelin-induced vasoconstriction and intracellular calcium mobilization.

Mechanisms for the antagonistic action of atrial natriuretic peptide (ANP) toward endothelin were studied. We examined the effects of ANP on endothelin-induced vasoconstriction in isolated perfused kidney and the elevation of intracellular free calcium concentration using Fura-2 in cultured rat vascular smooth muscle cells (VSMC). Endothelin produced an increase in renal vascular resistance in isolated perfused kidney (2 x 10(-10) mol/l, +109%; P less than 0.01). ANP completely abolished renal vasoconstriction induced by endothelin. Endothelin produced a biphasic elevation in intracellular calcium concentration in the VSMC. Ethyleneglycol-bis-(beta-amino-ethylether)-N,N,N',N'-tetr aac etic acid (EGTA; 3 mmol/l) or nicardipine (10(-8) mol/l) decreased the sustained elevation of intracellular calcium concentration by 10(-8) mol/l endothelin to the basal level (endothelin, +15% versus EGTA + endothelin, -1%; P less than 0.05; endothelin, +18% versus nicardipine + endothelin, +5%; P less than 0.01). Pretreatment with 10(-6) mol/l ANP suppressed neither the peak phase of intracellular calcium concentration elevation (endothelin, 10(-8) mol/l, +35% versus endothelin + ANP, +31%; not significant) nor the sustained phase of intracellular calcium concentration elevation (endothelin, 10(-8) mol/l, +21% versus endothelin + ANP, +16%; not significant). ANP markedly increased the production of cyclic 3',5'-guanosine monophosphate (cGMP) in the VSMC (ANP, 10(-6) mol/l, +1100%; P less than 0.01). However, endothelin did not influence cGMP production in the presence or absence of ANP. ANP may antagonize the vasoconstrictive action of endothelin through an effect on the steps subsequent to the mobilization of intracellular calcium in the pathway of vascular smooth muscle contraction.

Animals↗
PubMed1986

Earlobe crease and coronary heart disease in Japanese.

To evaluate whether a significant statistical correlation exists between earlobe crease (EC) and coronary heart disease (CHD), 1000 Japanese adult patients (573 males, 427 females) were examined for the presence or absence of EC, clinical or angiographic evidence of CHD, and the following coronary risk factors: male sex, age over 50 years, obesity, hypertension, diabetes mellitus, cigarette smoking, and hyperlipidemia. Patients were divided into two groups according to clinical evidence of CHD: 237 patients with angina pectoris and/or myocardial infarction (CHD+ group); 720 patients without evidence of CHD (CHD- group). Coronary angiography was performed on 200 patients from this sample population; these patients were also divided into two groups: 119 patients with greater than 50% luminal narrowing of at least one major coronary artery (stenosis+ group); 81 patients with no significant atherosclerotic changes in the coronary arteries (stenosis- group). EC was present in 58 of 237 CHD+ patients (24.5%) but in only 35 of 720 CHD- patients (4.8%; P less than 0.001); it was present in 31 of 199 stenosis+ patients (26.1%) but in only 3 of 81 stenosis- patients (3.7%; P less than 0.01). EC was also found to correlate significantly with some coronary risk factors; the correlations between the presence of EC and the presence of CHD and coronary risk factors were investigated by multivariate analysis. In a multivariate setting, the existence of CHD and an age of over 50 years was significantly related to the presence of EC. To investigate the relationship between EC and advancing age, all patients were separated into age-groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1984

Rabbit hearts for the critical evaluation of drugs to reduce the size of experimentally produced acute myocardial infarction.

Using more than 500 rabbits, we found that the rabbit heart is a good model for the evaluation of drugs which affect acute myocardial infarction (AMI) size. When the ratio of the epicardial coloration area to the long axis length of the left ventricle was controlled immediately after the ligation of the left anterior descending coronary artery and small branches of the left circumflex artery, it was possible to estimate the size of the ischemic region because AMI region in rabbit heart was always transmural. The necrotic region in the left ventricle was determined by phosphorylase histochemistry 24 hours after the operation. The incidence of arrhythmia and death following the operation was negligible. Then, we evaluated several drugs to examine their effects on AMI size. Propranolol (1, 2, and 4 mg/Kg) and verapamil (0.25, 0.5, and 1.0 mg/Kg) reduced AMI size, although the mortality and AMI size increased at higher doses of verapamil. Another Ca2+ antagonist, diltiazem (2 mg/Kg) and an adenosine potentiator, dilazep (2 mg/Kg) also decreased AMI size, while nicardipine, a water soluble, photoresistant nifedipine analogue (0.01, 0.05, and 0.1 mg/Kg) did not show a significant effect. These data suggest that this rabbit model is useful for assessing drug effects on AMI size and that the mechanism(s) of action of nicardipine may differ from other Ca2+ antagonists.

Animals↗