Biomedical subjects

T Satoh

Publications and source records attributed to T Satoh.

At least 595 records · Page 33Linked to original sources

PubMed1995

Transcriptional down-regulation by epidermal growth factor of TRH receptor mRNA in rat pituitary cells.

To gain insight into the mechanism underlying the epidermal growth factor (EGF)-induced changes in responsiveness to TRH and in the numbers of TRH receptors (TRH-Rs) in the pituitary, we investigated the transcriptional regulation by EGF of the TRH-R gene in GH4C1 cells. Northern blot analyses and binding studies revealed that EGF reduced both TRH binding and TRH-R mRNA levels in a dose- and time-dependent manner, while no significant changes were observed in beta-actin mRNA levels. Addition of actinomycin D caused an acute increase in the basal TRH-R mRNA level, and the rate of decrease of the TRH-R mRNA was identical in control and EGF-treated groups, suggesting that the stability of the TRH-R mRNA was not significantly affected in EGF-treated cells. Incubation with cycloheximide also induced an increase in the basal TRH-R mRNA level and completely reversed the EGF-induced reduction of TRH-R mRNA levels. Furthermore, a nuclear run-on assay demonstrated that the rate of transcription of the TRH-R gene was significantly inhibited in cells treated with EGF. We conclude that (1) EGF decreases the expression of the TRH-R mRNA largely by reducing its rate of transcription, and this action requires the synthesis of new proteins, and (2) inhibitors of protein and RNA synthesis cause a significant increase in the basal TRH-R mRNA level, suggesting that there may be a short-lived protein suppressing the TRH-R mRNA level in the pituitary.

Animals↗

PubMed1995

Nonrandom distribution of sister chromatid exchanges in the chromosomes of three mammalian species.

The frequency and distribution of mitomycin C (MMC)-induced sister chromatid exchanges (SCEs) were investigated in the fibroblast chromosomes of three mammalian species, Microtus montebelli, Apodemus argenteus and Chimarrogale himalayica, by the fluorescence-plus-Giemsa (FPG) and C-band staining methods, paying special attention to the large C-band area (C-block)-carrying and/or nucleolus organizer region (NOR)-carrying chromosomes. The junctions of heterochromatin and euchromatin (HE-junctions) and NORs were found to be "hot spots" of SCEs in all the species examined: their SCE frequencies were 35.3% and 24.2% in the HE-junction of the X chromosomes of M. montebelli and A. argenteus, and 16.7% and 17.8% in the NORs of the No. 1 chromosomes of M. montebelli and C. himalayica, respectively. In M. montebelli and A. argenteus the SCE frequency was apparently lower in the C-block region than in the euchromatic one, when compared with each other based on equal length, while in C. himalayica no such marked difference in the SCE frequency was found between these two regions of the chromosome. These findings may indicate that occurrence of SCEs is significantly suppressed in the C-block region of M. montebelli and A. argenteus, but not in that of C. himalayica. In addition, the C-blocks of the No. 1 homologue of C. himalayica showed a highly varied individual-to-individual heteromorphism in length. The biological implication of SCEs was discussed in connection with the generation of heteromorphism.

Animals↗

PubMed1995

Metabolism of a nitrate ester, dihydropyridine derivative in rabbit hepatic microsomes and cytosol.

1. The metabolism of a nitrate ester-substituted dihydropyridine derivative (NND) in vitro was characterized with rabbit hepatic microsomes and cytosol. 2. Denitration activity was located in both the microsomal and cytosolic fractions, whereas oxidation to the pyridine analogue was solely located in the microsomal fraction. 3. Oxidation to the pyridine analogue required NADPH and was inhibited by carbon monoxide, miconazole and SKF-525A, suggesting that oxidation was catalysed by P450. 4. Denitration activity in the microsomes required either NADPH or GSH. Together with these results, responses to various inhibitors indicate participation of both P450 and glutathione S-transferase (GST). 5. Denitration activity in cytosol was activated by glutathione (GSH), and by dithiothreitol (DTT) to a greater extent. GSH-dependent denitration was inhibited by S-hexyl GSH, an inhibitor of GST, but DTT-dependent denitration was not. Moreover, the formation patterns of the mono-denitrated metabolites, M1 and M2, were shown to be different in each incubation condition. 6. These results suggest that the denitration of NND in cytosol could be catalysed by a GSH-independent enzyme as well as the GSH-dependent enzyme, GST.

Animals↗

PubMed1995

Monamidocin, a novel fibrinogen receptor antagonist. I. Production isolation, characterization and structural elucidation.

Monamidocin, a novel fibrinogen receptor antagonist, has been isolated from the culture broth of Streptomyces sp. NR 0637 BY carbon adsorption, n-BuOH extraction, SP-Toyopearl, silica gel 60 silanised and Sephadex LH-20 column chromatographies and preparative HPLC. The molecular formula of monamidocin has been determined to be C15H22N4O4 from HRFAB-MS and 13C NMR spectral data. The structure of monamidocin has been determined to be N-[(S)-5-guanidino-2-hydroxypentanoyl]-L-phenylalanine by 2D NMR experiments.

Chemical Phenomena↗

PubMed1995

Monamidocin, a novel fibrinogen receptor antagonist. II. Biological activity and structure-activity relationships.

Monamidocin, a fibrinogen receptor binding inhibitor produced by Streptomyces sp. NR 0637, inhibits the binding of fibrinogen to its receptor with an IC50 of 0.21 microM. It also inhibits ADP-collagen- and thrombin-induced aggregation of human platelet with IC50S of 46, 30, and 77 microM, respectively. To obtain more potent inhibitors, twenty analogs have been synthesized, among which N-[(R)-5-guanidino-2-hydroxypentanoyl]-L-tyrosine is the most potent. It inhibits the binding of fibrinogen to its receptors with an IC50 of 0.022 microM and is about ten times more potent than monamidocin.

Adenosine Diphosphate↗

PubMed1995

Sulfobacins A and B, novel von Willebrand factor receptor antagonists. I. Production, isolation, characterization and biological activities.

Sulfobacins A and B, novel von Willebrand factor (vWF) receptor antagonists, have been isolated from the culture broth of Chryseobacterium sp. (Flavobacterium sp.) NR 2993 by ethyl acetate extraction, and by Sephadex LH-20 and silica gel column chromatographies. The physico-chemical properties of the sulfobacins indicate that their structures are completely different from that of aurintricarboxylic acid, the one known vWF receptor antagonist. Sulfobacins A and B inhibit the binding of vWF to its receptor with IC50S of 0.47 and 2.2 microM, respectively. Sulfobacin A also inhibits ristocetin-induced agglutination in human platelets fixed with paraformaldehyde with an IC50 of 0.58 microM.

Alkanesulfonic Acids↗

PubMed1995

Sulfobacins A and B, novel von Willebrand factor receptor antagonists. II. Structural elucidation.

Sulfobacins A and B are novel von Willebrand factor (vWF) receptor antagonists produced by Chryseobacterium sp. NR 2993. The structures of sulfobacins A and B have been determined to be (2R,3R)-3-hydroxy-2-[(R)-3-hydroxy-15-methylhexadecanamido]-15- methylhexadecanesulfonic acid and (2R,3R)-3-hydroxy-15-methyl-2-[13-methyltetradecanamido]- hexadecanesulfonic acid, respectively, by various 2D NMR experiments and by methanolysis. The absolute configurations of the sulfobacins were determined by a modified MOSHER's method. The structures are related to sulfonolipids, major components of the cell envelope of gliding bacteria of the genus Cytophaga.

Alkanesulfonic Acids↗

PubMed1995

[Detection of Mycobacterium tuberculosis by amplification of mycobacterial DNA from pleural fluid and gastric juice: the comparison of IS6110 gene with Amplicor mycobacterium].

The polymerase chain reaction (PCR) using oligonucleotides based on the repetitive sequence (IS6110) of Mycobacterium tuberculosis and Amplicor Mycobacterium, which combines a PCR with the hybridization assay, were evaluated for detection of M. tuberculosis in pleural fluid and gastric juice. The detection limits of these two assay systems for cultured M. tuberculosis were less than 2 cells/ml, as compared with 200 cells/ml by culture. A total of 42 pleural fluid and 94 gastric juice specimens were examined. A total of 5 pleural fluid and 5 gastric juice were culture positive for M. tuberculosis. Only the PCR gave positive results in 2 pleural fluid of which laboratory findings are characteristic of tuberculous pleuritis, and in one gastric juice of the patient who was diagnosed as having pulmonary tuberculosis. Sensitivity, specificity and positive predictive value for IS6110 gene were 75%, 94% and 71.1%, respectively, in pleural fluid. Two of three positive specimens for IS6110 gene from pleural fluid were negative for Amplicor Mycobacterium. These specimens resulted in positive with Amplicor Mycobacterium when solvent extracted DNA was used. Both the PCR systems had the same sensitivity (80%), specificity (98.8%) and positive predictive value (83.3%) in gastric juice. The PCR systems would be useful for rapid detection of M. tuberculosis without long term culture and for detection of non-cultured one from pleural fluid as well as gastric juice. However, when the presence of an inhibitor of PCR is suspected in a specimen, DNA should be purified from the specimen before amplification.

Adult↗

PubMed1995

[A case of renovascular hypertension with nephrotic syndrome].

A 68-year-old male patient with renovascular hypertension (RVHT) and nephrotic syndrome (NS) is described. He was admitted to our hospital for detailed investigation of severe hypertension and massive proteinuria. After admission, a diagnosis of RVHT with a right non-functional kidney and NS was made. Nephrectomy and contralateral renal biopsy were performed for refractory hypertension and detailed investigation of the NS, respectively. The renal biopsy showed focal segmental glomerulosclerosis (FGS) in the left kidney, whereas the nephrectomised kidney exhibited only ischemic change. After the operation, his blood pressure became stable without anti-hypertensive agents, but proteinuria remained in the nephrotic range. Six months later, proteinuria had disappeared and his renal function was stable. These findings suggest that NS and FGS might have resulted from an activated renin-angiotensin-axis and that the prolonged NS was due to severe glomerular injury. Although there have been many reports describing the relationship between RVHT and FGS in an experimental environment, this relationship is very rare in clinical cases. Therefore we present this case to increase understanding of the cause of FGS.

Aged↗

PubMed1995

[Generalized angitis and recurrent infection associated hemophagocytic syndrome in a girl with XXX syndrome].

We have encountered a case of a girl with XXX syndrome who had infection associated hemophagocytic syndrome (HPS) recurrently. The patient presented hyper-gammaglobulinemia during the clinical course and developed IAHS probably because of infection with Rubella virus and EB virus each as a trigger. Diseases that cause abnormality in X chromosome are said to present immune abnormality such as SLE in many cases. It is possible that the excessive X chromosome in this cases partially concerned with such as an immune abnormality as to cause recurrent IAHS.

Adolescent↗

PubMed1995

[Chemiluminescence assays for cytokines in serum: influence of age, smoking, and race in healthy subjects].

Evidence is accumulating that cytokines are important intermediates in the pathogenesis of many diseases such as asthma and pulmonary fibrosis. However, a major limitation to clinical studies of cytokines has been the inability to measure these important biomarkers in serum from normal, healthy controls. Without this capability, interpretation of apparently elevated levels in problematic, and evaluation of diseased level is impossible. We have recently developed chemiluminescence ELISA (CL-ELISA), resulting in a 100-fold increase in sensitivity. To assess the influence of age, smoking, and race on serum cytokine levels in healthy population, we measured IL-4, 5, 6, 10, IFN-gamma, and GM-CSF in serum of healthy Japanese (n = 38), and Americans (n = 10) using CL-ELISA. In this small population with narrow age range, no difference between smokers and nonsmokers was found for any cytokine. No correlations between age and cytokines was demonstrated. However, Japanese samples had lower levels of IL-4, 5, and 10 than American samples. Further evaluation using more controlled study design and larger populations will be necessary to determine whether this difference is due to inherent racial differences in Th2 cell function.

Adult↗

PubMed1995

Desmoplastic fibroma. Aggressive curettage as a surgical alternative for treatment.

In this article, the authors present 5 patients with desmoplastic fibroma and review the literature. Four patients had aggressive curettage with bone graft, and 1 had aggressive curettage alone. Although the literature reports that many patients have recurrence after curettage, there have been no recurrences in these 5 patients during followup periods ranging from 5 years 6 months to 9 years. Although wide excision has been recommended in the literature, treatment with aggressive curettage achieved clinical and radiographic control of the lesions for at least an intermediate duration of followup.

Adolescent↗

PubMed1995

[Analysis of familial aggregation of ovarian and breast cancer in patients with ovarian cancer].

In 118 patients with common epithelial ovarian tumors (carcinomas and tumors of borderline malignancy) treated at Tsukuba University Hospital and Tsukuba-Gakuen Hospital, family histories of ovarian and breast cancer were obtained from medical records or in interviews, and familial aggregation of these cancers was examined. 1. A positive family history was found in 10 patients (8.5%). The high incidences of familial ovarian cancer and ovarian cancer in patients who were previously affected with breast cancer were statistically significant. 2. Patients with serous adenocarcinoma showed a significantly greater rate of positive family history than those with mucinous adenocarcinoma. 3. No significant correlation was seen between the clinical stage and a positive family history. 4. Every patient except one with a positive family history had onset of ovarian cancer after menopause. The age at onset for familial ovarian cancer cases was younger than that for the patients' relatives who were affected previously. 5. There were 14 healthy women considered to be at high risk for ovarian cancer among 5 familial ovarian and 2 familial ovarian and breast cancer aggregations. These preliminary findings suggest that screening for early ovarian cancer should be conducted in high risk relatives of familial cancer patients and women affected with breast cancer previously. More detailed studies are needed to define the occurrence of familial or hereditary ovarian and breast cancers in Japan.

Adenocarcinoma, Mucinous↗

PubMed1995

[An immunohistological study on expression of glutathione S-transferase pi (form) in human ovarian carcinoma].

Specimens from 102 cases of ovarian cancer were stained immunohistochemically with a rabbit polyclonal antibody prepared against the placental form of the enzyme glutathione S-transferase (GST-pi). All 28 cases of mucinous adenocarcinoma, 19 of clear cell carcinoma and 4 of malignant transformed dermoid cysts were stained positively with the GST-pi antibody. These tumors are considered to be resistant to chemotherapeutic agents as compared with other epithelial tumors. With regard to the histological grade, the degree of staining was reduced according to the loss of differentiation. An investigation of the relationship between GST-pi stain and the prognosis of the 50 patients with stage 2,3 or 4, according to the Kaplan-Meier method, revealed that the prognosis improved as the staining decreased. In conclusion, results suggested that immunohistochemical staining of GST-pi is correlated with the chemoresistance of the tumor, and may predict the outcome in patients with ovarian cancer.

Adenocarcinoma, Clear Cell↗

PubMed1995

GSH-independent denitration of organic nitrate esters in rabbit hepatic and vascular cytosol.

The denitration of organic nitrate esters in rabbit hepatic cytosol was characterized. Sephadex G-200 chromatography of ammonium sulfate precipitate (40-80%) from hepatic cytosol demonstrated the presence of two distinct activities (peak I and peak II) responsible for the denitration of nitroglycerin (NTG) and isosorbide dinitrate (ISDN). The denitration of peak I required dithiothreitol (DTT), but not glutathione (GSH), and was not inhibited by S-alkyl GSH, an inhibitor of glutathione S-transferase (GST). Whereas, the denitration activity of peak II was potentiated by GSH, and was inhibited by S-alkyl GSH. These results strongly suggest that the denitration of organic nitrate esters, such as NTG and ISDN, can be catalyzed by at least two enzymes, GSH-independent denitration (peak I) and the GSH-dependent denitration (peak II, GST), in rabbit hepatic cytosol. The denitration activity of peak I was inhibited by SH-modified reagent, indicating that free thiol(s) is (are) critical for expression of the denitration activity. Also, in rabbit vascular cytosol, the cofactor requirement for denitration and response to S-hexyl GSH suggest the participation of GSH-independent enzyme which is responsible for the denitration of organic nitrate esters.

Animals↗

PubMed1995

Changes in adrenal carbonyl reductase activity in pregnant rats.

Changes in adrenal carbonyl reductase (CR) activity during pregnancy and postparturition in rats were investigated using two substrates, 13,14-dihydro-15-keto-prostaglandin F2 alpha (15KD-PGF2 alpha) and p-nitroacetophenone (PNAP). 15KD-PGF2 alpha reductase activity showed the lowest level on day 16 of pregnancy and steeply increased on the morning of postpartum day 1. PNAP reductase activity did not change up to day 18 of pregnancy, then was gradually increased and maintained the highest levels between day 19 and the morning of day 21 of pregnancy. Thereafter, the enzyme activity was rapidly decreased after parturition, on the contrary of changes in the 15KD-PGF2 alpha reductase activity. On the other hand, exogenous glucocorticoid treatment increased the 15KD-PGF2 alpha activity and decreased the PNAP reductase activity in adrenal glands of nonpregnant animals. Thus, it is found that the adrenal CRs in the above two classes are regulated by different mechanisms. As maternal corticosterone level is increased rapidly during late pregnancy by maternal transfer of fetal corticosterone, the present results suggest that adrenal CR activity during pregnancy, in particular at periparturition, may be influenced by fetal corticosteroids.

Adrenal Glands↗

PubMed1995

[Surgical repair of distal aortic arch aneurysm with hypothermic retrograde cerebral perfusion through standard left postero-lateral thoracotomy].

Five patients with aneurysm involving distal aortic arch underwent graft replacement of distal aortic arch and, in two patients, reconstruction of left subclavian artery through standard left postero-lateral thoracotomy with hypothermic retrograde cerebral perfusion. Retrograde cerebral perfusion with oxygen saturated venous blood could be performed by simply elevating central venous pressure to 20-23 mmHg in the Trendelenburg position and under controlling venous drainage from PA during deep hypothermic (19 degrees C) perfusion of the lower half of the body with the descending aorta occluded. Cardioplegia was induced by administration of cold blood cardioplegic solution into coronary circulation through Foley balloon catheter wedged in ascending aorta. Retrograde cerebral perfusion time was 30-77 min (mean 55 +/- 17 min), and pump time was 156-193 min (mean 168 +/- 15 min). There were no complications neurologically. In conclusion, this method rendered surgical repair of distal aortic arch aneurysm through left postero-lateral thoracotomy with both cerebral and cardiac protection able. Since any clamping of aortic arch and its branch was not necessary during above surgical procedure, cerebral emboli due to atheroma or luminal thrombus in aortic arch was prevented.

Aged↗

PubMed1995

Evaluation of cerebral infarction with iodine 123-iomazenil SPECT.

UNLABELLED: This study evaluates ischemic damage to central benzodiazepine (BZD) receptor binding in the brain with [123]iomazenil SPECT in relation to CT hypodense lesions and blood flow abnormalities. METHODS: Nine patients with middle cerebral artery territory infarction were studied. Iomazenil images obtained 180 min postinjection were analyzed for BZD receptor binding. The cortical infraction, visualized as CT hypodense area on CT, the peri-infarct area, visualized as normodensity surrounding the infarction on CT, the intrahemispheric remote area and the cerebellum were analyzed by taking the ratio of the lesion to contralateral mirror region (L/C ratio). CT during the chronic stage and perfusion images obtained during the smallest time difference between the two studies were used for comparative analysis. RESULTS: The mean L/C ratio of iomazenil uptake was 0.53 +/_ 0.08, 0.79 +/- 0.07, 0.98 +/- 0.03 and 1.00 +/- 0.04 in the infarct, peri-infarct and remote areas and the cerebellum, respectively. The infarct and peri-infarct areas showed significant decrease compared with unity. The corresponding mean L/C ratio for blood flow was 0.52 +/- 0.08, 0.73 +/- 0.07, 0.83 +/- 0.09, and 0.80 +/- 0.07, respectively. In all areas, the ratios were significantly decreased compared with unity. There was significant difference between the L/C ratio for blood flow and iomazenil in the remote area and the cerebellum. CONCLUSION: Iodine-123-iomazenil SPECT imaging may provide new information on ischemic damage to the brain, particularly neurons.

Aphasia, Broca↗