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Biomedical subjects

T Yagi

Publications and source records attributed to T Yagi.

At least 451 records · Page 25Linked to original sources
PubMed1992

Metabolic activation of sennoside C in mice: synergistic action of anthrones.

Sennosides A and C directly injected into the caecum of mice showed equal purgative activity. Intracaecal administration reduced time to onset of diarrhoea induced by sennoside C from about 3 h after oral administration to about 24 min. At 2.3 h after oral administration of sennoside C, nearly equimolar amounts of aloe-emodin anthrone and rhein anthrone were detected in the large intestine of mice. The purgative effect of oral sennoside C could be reduced by pretreating mice with chloramphenicol. This was observed as a decreased formation of total anthrones in the large intestine. Both anthrones and an equimolar mixture of both anthrones directly injected into the caecum exerted a purgative effect, although the activity was lower for aloe-emodin anthrone. The intracaecal ED50 values were 54.5 (24.1-89.6), 11.4 (5.0-15.7) and 11.2 (6.1-14.6) mumol kg-1 for aloe-emodin anthrone, rhein anthrone and an equimolar mixture of both anthrones, respectively. We concluded that aloe-emodin anthrone and rhein anthrone, formed mainly by intraluminal bacterial action, are the true active metabolites of sennoside C in mice and that both anthrones synergistically exert their purgative effects on mice.

Animals↗
PubMed1992

Vestibular disorders following immune response of the endolymphatic sac in the guinea pig.

The effect of a direct antigen challenge to the endolymphatic sac on vestibular function was investigated in guinea pigs. Following keyhole limpet hemocyanin (KLH) challenge to the sac in systemically presensitized guinea pigs, caloric responses were examined in 18 animals on days 1, 7, 14, 21, and 28. Caloric responses were significantly suppressed in 13 animals by day 7; of these, 5 animals had recovered by day 14 and 8 animals had not yet recovered by day 28. The behavior of spontaneous nystagmus was examined every hour in 10 animals at intervals of 3 to 56 hours after sac challenge. Irritative spontaneous nystagmus preceding paralytic nystagmus appeared in 5 animals, for which the mean onset was 14.6 +/- 3.1 hours and the mean duration was 4.4 +/- 6.5 hours. Paralytic spontaneous nystagmus appeared in all animals, for which the mean onset time was 23.3 +/- 12.3 hours. Neither direct KLH primary challenge of the sac nor phosphate-buffered saline injection to the sac caused significant changes in the vestibular function. These results suggest that an immune response of the sac induces a vestibular disorder and may produce an attack of vertigo similar to that of Meniere's disease.

Aged↗
PubMed1992

Immunoelectron microscopy of carbonic anhydrase isozyme VI in rat submandibular gland: comparison with isozymes I and II.

Carbonic anhydrase (CA) was purified from the saliva of pilocarpine-treated rats by inhibitor-affinity chromatography, and its localization in the rat submandibular gland was studied by the indirect immunoperoxidase technique using a monoclonal antibody (MAb) raised against the enzyme. SDS-polyacrylamide gel electrophoresis of the CA VI gave three bands of 33, 39, and 42 KD. Enzyme digestion experiment showed that the 42 KD molecule was degraded into the 39 KD molecule and the 39 KD molecule into the 33 KD molecule. The cleavage of the 42 KD molecule was independent and that of the 39 KD molecule was dependent on endo-beta-N-acetylglucosaminidase F. The 42 KD molecule was detected in the CA purified from the pilocarpine-treated but not the untreated salivary gland. The MAb recognized all the three components of the enzyme. Immunostaining for CA VI was seen in the cytosol and secretory granules of serous acinar cells and in the duct luminal contents. Staining specific for erythrocyte CA (CA I and CA II) was observed in the cytosol of the epithelial cells of granular, striated, and excretory ducts. Among these duct cells, the agranular varieties in the granular and excretory ducts were essentially devoid of the immunoreactivity.

Animals↗
PubMed1992

Effect of captopril on isoproterenol-induced cardiac hypertrophy and polyamine contents.

It is well known that isoproterenol (ISO) a nonselective beta adrenoceptor agonist induces cardiac hypertrophy. It can be assumed that, in addition to its direct cardiac effect, ISO has a cardiac trophic effect via stimulation of the renin angiotensin system. Synthesis of polyamines is facilitated in cardiac hypertrophy and polyamine levels are rapidly elevated prior to an increase in heart weight. In the present study, we investigated whether captopril (30 mg/kg body weight, daily) could attenuate cardiac hypertrophy and elevation of cardiac polyamine levels in rats, which effects were elicited by a chronic (1- or 2-weeks) and repeated administration of a small dose (0.5 mg/kg body weight) of ISO. Cardiac hypertrophy was assessed by an increase in the wet weight and RNA content of the heart. Polyamines were analyzed by HPLC. Captopril alone did not affect either heart weight/body weight ratio or cardiac contents of polyamines and nucleic acids at the end of the second week. In isoproterenol-treated rats, the above parameters, except for putrescine content on day 14, were significantly increased on both day 7 and day 14. Captopril slightly attenuated ISO-induced cardiac hypertrophy and significantly prevented the ISO-evoked increase in the contents of RNA, spermidine, and spermine at the end of the second week. These results suggest that the ISO-evoked increase in cardiac polyamines was mediated, at least in part, by the renin angiotensin system, which was stimulated by ISO.

Animals↗
PubMed1992

Oxidative damage to the membrane of canine erythrocytes with inherited high Na, K-ATPase activity.

Oxidative damage to the membrane in canine erythrocytes with inherited high Na, K-ATPase activity (HK cells) was compared with that in normal canine cells (LK cells). When 30 mM beta-acetylphenylhydrazine (APH) was applied to HK and LK cells, lipid peroxidation and hemoglobin denaturation occurred. Lipid peroxidation determined from malondialdehyde (MDA) formation was significantly lower in HK than in LK cells so far as endogenous glutathione (GSH) concentration was maintained at appropriate levels. With the depletion of GSH, MDA formation was accelerated and difference between HK and LK cells was not significant. Denatured hemoglobin bound to the membrane protein was less in HK than in LK cells. During incubation with APH, osmotic fragility increased markedly in LK cells, while HK cells showed very little change. The amounts of total lipid, total and free cholesterol, glycolipid, phospholipid and fatty acids were essentially the same in both cell types. Fatty acid compositions showed very small differences. The membrane of HK cells thus appear to have greater protection against oxidative damage induced by APH, owing to the presence of excess GSH in HK cells. The capability of HK cells to withstand oxidative damage would not be due to differences in membrane lipid compositions.

Animals↗
PubMed1992

[The study of pulmonary tuberculosis in the elderly].

A clinical study of 52 patients diagnosed as having pulmonary tuberculosis at National Chiba-Higashi Hospital between 1988 and 1990 was performed. The cases ranged in age from 80-89 years; mean male patient age was 82.5, and mean female patient age was 84.3. Diagnosis of the cases were as follows: 19 discovered when checking into hospital because of chest symptoms; 14 diagnosed during the treatment of other diseases; 14 diagnosed during admission to the hospital for other diseases; and five cases were detected by chest X-rays. A total of 38 cases, had received primary treatment for pulmonary tuberculosis, 11 cases had received secondary treatment, and three cases were receiving treatment for tuberculosis. Upon admission to the hospital after the detection of tuberculosis, 19 cases tested positive to sputum smear examinations, six cases tested positive to culture examinations but negative to smear examinations, and culture examinations were negative in 27 cases. Regarding the chest X-ray findings, using the criterion of roentgenological classification for pulmonary tuberculosis established by the Japanese Society for Tuberculosis, two cases revealed type I, 29 cases revealed type II, and 21 cases revealed type III. Cavitary cases were observed in 60% of the chest X-ray findings. Upon hospital admission, 18 cases were observed to have circulatory diseases, 16 cases had central nervous diseases, 12 cases had digestive diseases and 11 cases had respiratory diseases. Nine cases had malignant neoplasm, five cases had diabetes mellitus and 14 cases had other diseases. A total of 18 cases ended in death; six cases died of pulmonary tuberculosis, and 12 cases died of other diseases.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

[An autopsy case of massive pulmonary hemorrhage in systemic lupus erythematosus].

A 60-year-old female was admitted to our hospital because of respiratory failure. She was diagnosed as having systemic lupus erythematosus (SLE) in 1971 and had been treated with low-dose oral corticosteroids for 13 years. She developed cough, fever and anemia several days after oral corticosteroids were tapered. Initially, she had no complications such as congestive heart failure, renal failure or bleeding tendency. Respiratory failure progressed without any response to antibiotic therapy. Chest roentgenogram showed bilateral diffuse infiltrates and air bronchograms. There was no improvement even with steroid pulse therapy, and she died of multiple organ failure. Autopsy revealed massive intra-alveolar hemorrhage and interstitial pneumonitis. Deposition of immunoglobulins in the lung was not seen. To our knowledge, this is the 11th reported case of SLE associated with pulmonary hemorrhage in Japan.

Female↗
PubMed1992

[Development of endolymphatic hydrops following immune response in the endolymphatic sac of guinea pigs--long-term observation].

We report findings for endolymphatic hydrops in specimens obtained 5 to 28 weeks after a direct challenge with secondary KLH antigen to the endolymphatic sac (ES) of guinea pigs. Following gradual disappearance of endolymphatic hydrops (EH) in the period between the 5th and 8th weeks, the inferior labyrinth EH gradually developed again from the 3rd month onward in the saccule and from the 4th month onward in the cochlea. Many lymphocytes and plasma cells infiltrated into the perisaccular space for up to 7 months. These results suggest that an immune response in the ES may ultimately induce chronic dysfunction of the ES and thereby lead to progressive EH.

Animals↗
PubMed1992

Regulation of intracellular osmotic pressure during the initial stages of salt stress in a salt-tolerant yeast, Zygosaccharomyces rouxii.

The accumulation of glycerol and inorganic ions as it related to osmotic pressure, and the regulation of intracellular osmotic pressure in a salt-tolerant yeast, Zygosaccharomyces rouxii, were examined for several hours after salt stress. Intracellular contents of glycerol increased for up to 6 h in media supplemented with 1 M and 2 M NaCl and did not increase in medium containing 3 M NaCl. Intracellular contents of Na+ and Cl- reached a maximum value within 1 and 3 h, respectively, in all NaCl-containing media and increases were proportional to the concentration of NaCl in the medium. As glycerol was accumulated in cells, the intracellular contents of Na+ and Cl- gradually decreased in media containing 1 M and 2 M NaCl. After salt stress, cell volume decreased within 1 h and the original volume was re-established for 3 to 6 h in media with 1 M and 2 M NaCl but not in medium with 3 M NaCl. Intracellular concentrations of solutes, which were calculated from the total contents of glycerol and inorganic ions and the cell volume, became almost equivalent to the external osmotic pressure within 1 h after salt stress. Experiments using various inhibitors showed that a large amount of ATP was required not only for the synthesis and accumulation of glycerol but also for the exclusion of Na+ and Cl- from cells under salt-stressed conditions.

Culture Media↗
PubMed1992

[Cases of pulmonary tuberculosis found in the development of pneumothorax].

During the four-year period from 1987 to 1990, six cases of pulmonary tuberculosis, accompanied by the development of pneumothorax, were observed at our hospital. Distribution by sex was five males and one female. The mean age was 49.8 years-old. None of the patients suffered severe respiratory failure, and there were no deaths in this series. While many of the patients had bilateral exudative disease, five out of the six patients experienced pneumothorax on their right side. The realization of tuberculosis by both patients and doctor tended to be shorter than those cases without pneumothorax.

Adolescent↗
PubMed1992

[Atrioventricular block in acute inferior myocardial infarction].

The underlying mechanism of atrioventricular block (AVB) in acute inferior myocardial infarction (AIMI) is not clearly understood. In 33 (27 males and 6 females) of 123 patients with AIMI, second and/or high degree AVB was observed. In 14 of the 33 patients (42%), AVB transiently appeared within 24 hours after the onset of AIMI. In 13 patients (39%) AVB appeared after 24 hours. In the remaining 6 patients (18%), AVB appeared within 24 hours and disappeared thereafter. Among these 3 groups, there were no significant differences in age, sex, serum enzymes, the appearance of high degree AVB, pump failure or Forrester's classification II, III and IV and the necessity of temporary pacing. One mg of atropine sulfate was administrated intravenously 35 times in 19 patients. When AVB improved or the ventricular rate increased more than 30%, the drug was regarded as effective. Atropine was more effective when administrated after 24 hours (11%, less than or equal to 24 hours vs 60%, greater than 24 hours, p less than 0.05), and in patients with a slight degree of AVB (28% in high degree vs 80% in second degree, p less than 0.05) and rapid ventricular rate during high degree AVB (0%, less than 40/min vs 45%, greater than or equal to 40/min, p less than 0.05). In the 6 patients not responding to atropine, 250 mg of aminophylline was given intravenously for 15 min. The effect was not seen in 4 patients, including 3 patients to whom it was administrated within 3 days after the onset of AIMI, and one patient to whom it was given on the 5th day. Aminophylline improved atrioventricular conduction on the 5th to 10th day after the onset of AIMI in 2 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine↗
PubMed1992

[Investigation of the cases due to Mycobacterium kansasii in our hospital].

A clinical study of 23 patients with Mycobacterium kansasii infection of the lung encountered at National Chiba Higashi Hospital from 1988 to 1990 was carried out. All 23 cases were male, aged from 25 to 81 years-old. Diagnoses were confirmed by sputum culture. The cases consisted of 15 primary infections and 8 secondary infections. Out of the 23 cases, 11 were detected by mass screening with chest X-ray findings, 10 cases were discovered when visiting the hospital because of chest complications and two cases were diagnosed during the observation of other diseases. On admission, sputum smear examinations were positive for 15 patients and negative for 8 patients. Chest X-ray findings using the roentgenological classification criterion for pulmonary tuberculosis established by the Japanese Society for Tuberculosis, 20 cases revealed a Type II shadow and three cases revealed a Type III shadow. One patient has died from another disease, two are undergoing chemotherapy, two have ceased chemotherapy treatment, and 18 patients have completed the treatment, Sputum cultures rapidly turned to negative for mycobacterium detection after chemotherapy treatment. The prognosis is considered to be quite good.

Adult↗
PubMed1992

[Pulmonary tuberculosis in youth].

The study of the group younger than 29 years of age with pulmonary tuberculosis was carried out. Thirty seven out of 287 tuberculosis patients who were discharged from National Chiba-Higashi Hospital in 1989 were enrolled. Only 5 patients (13.5%) were associated with complication. The smear and culture of sputum for acid-fast bacilli were positive in 30 cases (81.1%) and chest X-ray films revealed cavitary lesion in 31 cases (83.3%). Many of them were moderately advanced cases. Twenty four of them were found symptomatically, 10 by mass survey and 3 under treatment of other diseases. The total delay of symptomatic patients was 8.5 weeks until 80% of them were definitely diagnosed. The days of hospital stay were 122 until half patients were discharged. Five of them (13.5%) were non-Japanese and all stayed in Japan illegally. Their condition was rather severe.

Adolescent↗
PubMed1991

Analysis of N-methyl-N-nitrosourea-induced mutations in a shuttle vector plasmid propagated in mouse O6-methylguanine-DNA methyltransferase-deficient cells in comparison with proficient cells.

A shuttle vector plasmid, pYZ289, was constructed from the pZ189 plasmid and polyoma virus DNA. The plasmid contains a supF gene as a marker of mutation and can replicate in both Escherichia coli and mouse cells. The pYZ289 plasmids treated with N-methyl-N-nitrosourea were passed through mouse cells originating from skin tumors, which are either proficient (HL18) or deficient (HL8) in O6-methylguanine-DNA methyltransferase activity, and mutations in the supF gene were analyzed. In the repair-deficient HL8 cells, N-methyl-N-nitrosourea-treated pYZ289 showed lower plasmid survival and higher mutation frequency than in the repair-proficient HL18 cells. DNA sequence analysis in the mutated supF gene revealed that most mutations occurred in G:C base pairs (86% for HL8, 76% for HL18), and the frequency of G:C----A:T transition was higher in HL8 cells (69%) than in HL18 cells (31%). G:C----T:A transversions occurred more frequently in HL18 cells (31%) than in HL8 cells (12%). Mutations occurred frequently at the base pair positions of 123 and 159 of supF gene in HL18 cells and at 169 in HL8 cells. Analysis of the bases neighboring the mutations appeared to be related to the mutability of the base pairs with the sequence of 5'-purine-G-G-3' being the most frequently mutated. These results show that the new pYZ289 plasmid is useful for the analysis of mutations and that a deficiency in O6-methylguanine-DNA methyltransferase enhances the N-methyl-N-nitrosourea-induced mutation with significant specificity.

Animals↗
PubMed1991

Characterization of the 25-kilodalton subunit of the energy-transducing NADH-ubiquinone oxidoreductase of Paracoccus denitrificans: sequence similarity to the 24-kilodalton subunit of the flavoprotein fraction of mammalian complex I.

The NADH dehydrogenase complex isolated from Paracoccus denitrificans is composed of approximately 10 unlike polypeptides [Yagi, T. (1986) Arch. Biochem. Biophys. 250, 302-311]. Structural genes encoding the subunits of this enzyme complex constitute at least one gene cluster [Xu, X., Matsuno-Yagi, A., & Yagi, T. (1991) Biochemistry 30, 6422-6428]. The 25-kDa subunit (NQO2), which has been isolated from sodium dodecyl sulfate-polyacrylamide gels, is a polypeptide of this enzyme complex. The partial N-terminal amino acid sequence and amino acid composition of the NQO2 subunit have been determined. On the basis of the amino acid sequence, the NQO2 gene was found to be located 1.7 kilobase pairs upstream of the gene for NADH-binding subunit (NQO1). The complete nucleotide sequence of the NQO2 gene was determined. It is composed of 717 base pairs and codes for 239 amino acid residues with a calculated molecular weight of 26,122. The NQO2 subunit is homologous to the Mr 24,000 subunit of the mammalian mitochondrial NADH-ubiquinone oxidoreductase which bears an electron paramagnetic resonance-visible binuclear iron-sulfur cluster (probably cluster N1b). Comparison of the predicted amino acid sequence of the Paracoccus NQO2 subunit with those of its mammalian counterparts suggests putative binding sites for the iron-sulfur cluster. In addition, nucleotide sequencing shows the presence of two unidentified reading frames between the NQO1 and NQO2 genes. These are designated URF1 and URF2 and are composed of 261 and 642 base pairs, respectively. The possible function of the protein coded for the URF2 is discussed.

Amino Acid Sequence↗