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Biomedical subjects

T Ishida

Publications and source records attributed to T Ishida.

At least 361 records · Page 20Linked to original sources
PubMed1998

Automated fluorimetric determination of cellular cholesterol.

We developed a completely automated fluorimetric method for the determination of cellular cholesterol, consisting of enzymatic hydrolysis of cholesteryl ester to free cholesterol and enzymatic oxidation of free cholesterol in the presence of an indicator substrate to produce a fluorescent product. For control preparations of monocytes, the mean detection limit was 2.57 mumol/5 x 10(5) cells and the mean within-batch coefficients of variation were 9.30, 6.00 and 3.73% at mean cholesterol concentrations of 1.94, 9.05 and 12.49 mumol/5 x 10(5) cells, respectively. The results correlated well with those obtained by gas-liquid chromatography.

Adult↗
PubMed1998

Characterization of bovine serum factor triggering the lysis of liposomes via complement activation.

Our previous studies have shown that the degree of damage to a liposome corresponds to the variability of the animal species from which the serum comes, and that a complement activating factor (CAF) plays an important role in inducing the activation of the complement system, ultimately leading to the lysis of the liposomes. In this study, our attention focused on the characterization of the bovine serum factor (bCAF) that is involved in complement-mediated immune lysis of the liposome. The active fraction containing CAF partially purified with PEG and ammonium sulfate results in marked activation of the complement system via the alternative pathway when interacted with CAF-depleted serum, whereas the active fraction or CAF-depleted serum alone does not activate the complement. The interaction between lipopolysaccharide (LPS), heparin, zymosan or their mixture in place of CAF and CAF-depleted serum does not result in any significant activation of the complement system. Results from pretreatment with rabbit anti-bovine IgM IgG and rabbit anti-bovine IgG IgG indicate that activation of the complement system is not attributable to the antibody which is generally involved in activation of complement via the classical pathway. The results have further been proven by pretreatment with Concanavalin A (Con A) sepharose and protein G sepharose ruling out the possibility of antibody-mediated activation of complement. Our studies on collagenase and trypsin digestion demonstrate that the relative activity of CAF does not diminish with increase in collagenase concentration, and decreases with increase in trypsin concentration, strongly indicating that CAF does not have a collagen-like domain in its structure. The relative activity of CAF is dramatically inhibited after reduction with 2-mercaptoethanol (2-ME), clearly demonstrating that CAF is sensitive to reduction with 2-ME and confirming a sulhydryl-dependent protein. The optimal activity of CAF is observed in the range of 35-45 degrees C and its half-life at 37 degrees C is about 105 h. Furthermore, the relative activity of CAF increases and gradually approaches a plateau level with the increase of Mg2+ concentration. Obviously, complement activation induced by CAF depends on adequate Mg2+ concentration, confirming that this dependence is characteristic of the alternative pathway.

Ammonium Sulfate↗
PubMed1998

Spectroscopic investigation on the interaction of NCA0424, a potent antitumor indoloquinoxaline derivative, with DNA.

NCA0424 (1), an indoloquinoxaline derivative, has a potent antitumor activity against in vitro and in vivo tumor models. To elucidate its structure-activity relationship, the interactions with various B-form DNAs were investigated by thermal denaturation, viscosity and circular dichroism (CD) measurements. The thermal stability of the DNA duplex was increased by the interaction with 1, and preferable binding for alternative purine-pyrimidine base sequence was suggested. Comparative viscometric measurements with ethidium bromide (an intercalator) and distamycin (a minor groove binder) suggested that 1 is an intercalator. The interaction of DNA with 1 revealed a new CD band at 340-390 nm. Taking advantage of this induced CD band, the equilibrium binding constants were determined for various DNAs, and the binding preference of 1 for the alternative purine-pyrimidine base sequence, especially for the case of guanine as purine base, was indicated. The appearance of the induced CD band implies the importance of 1 side chain for the effective and/or stable intercalation of the aromatic ring into the DNA base pair.

Antineoplastic Agents↗
PubMed1998

5-HT1Dbeta receptor mediates the supersensitivity of isolated coronary artery to serotonin in variant angina.

Although serotonin (5-hydroxytryptamine; 5-HT) is used for provocation of coronary spasm, 5-HT receptor subtypes in spastic coronary arteries remain undetermined. We demonstrated the supersensitivity of isolated coronary artery to ergonovine, 5-HT, and sumatriptan, a 5-HT1D receptor agonist, in a patient with variant angina. Furthermore, we detected gene expression of 5-HT1Dbeta and 5-HT2A receptors in spastic coronary artery using RNase protection assay. These findings suggest that the leftward shift of the dose-response curve for 5-HT, which plays an important role in the pathogenesis of coronary spasm, is mediated by activation of 5-HT1Dbeta receptor.

Angina Pectoris, Variant↗
PubMed1998

Etiology of community-acquired pneumonia in hospitalized patients: a 3-year prospective study in Japan.

STUDY OBJECTIVE: To compare the etiology of community-acquired pneumonia in Japan and Western countries, the causative pathogens were prospectively investigated in patients requiring hospitalization. DESIGN: Prospective study over a 3-year period. SETTING: A community general hospital in Japan. PATIENTS: Three hundred twenty-six episodes of community-acquired pneumonia in 318 patients admitted to the hospital between July 1994 and June 1997. METHODS: The microbiological diagnosis was based on the results of quantitative sputum culture, blood culture, and other invasive procedures, including transthoracic needle aspiration or bronchoscopic examination. Serologic tests for Mycoplasma pneumoniae, Chlamydia spp, Legionella spp, and viruses were also routinely performed. RESULTS: Causative pathogens were identified in 199 episodes (61%). Streptococcus pneumoniae was the most common pathogen (23%), followed by Haemophilus influenzae (7.4%), M pneumoniae (4.9%), and Klebsiella pneumoniae (4.3%). The Streptococcus milleri group and Chlamydia pneumoniae were detected in 3.7 and 3.4% of the episodes, respectively. Pneumonia due to Legionella spp was recognized in only two patients. CONCLUSIONS: The etiology of community-acquired pneumonia in Japan did not differ markedly when compared with that of Western countries except for the low incidence of Legionella pneumonia. C pneumoniae and the S milleri group, which are emerging or newly recognized pathogens, were also significant causative microorganisms.

Adolescent↗
PubMed1998

Expression of truncated pro-opiomelanocortin gene transcript in human leukemia cell lines.

Although previous studies have suggested that human peripheral blood mononuclear cells (PBMCs) may express pro-opiomelanocortin (POMC) mRNA and synthesize its related peptides, the patho-physiological role of POMC expressed in peripheral cells is not known. In this study, we investigated the POMC gene expression in various types of human leukemia cell lines by Northern blot analysis and the reverse transcribed-polymerase chain reaction (RT-PCR) method. The POMC mRNA was not detected by Northern blot analysis in all cell lines tested except the Jurkat cell line which is derived from T-lymphoblastic leukemia. The POMC mRNA expressed in the Jurkat cells was smaller than that in the human anterior pituitary gland. The RT-PCR method revealed that a truncated-POMC transcript could be detected not only in lymphoblastic leukemia cells but also in erythroid and myeloid cells. Interestingly, two cell lines of monocytic leukemia, J-111 and U937, did not express the truncated-POMC mRNA. Treatment with concanavalin-A stimulated truncated POMC mRNA expression and ACTH-like immunoreactivity in lymphoblastic leukemia cells with T-(Jurkat) and B-(BALL-1) lymphocyte phenotypes. These results confirm that human leukemia cells except for monocytic cells express a truncated-POMC mRNA as well as in the human normal PBMC.

Adrenocorticotropic Hormone↗
PubMed1998

Lipoatrophy induced by recombinant human insulin injection.

A 79-year-old man had been treated with recombinant human insulin since the age of 77. He developed subcutaneous fat atrophy around the injection site 16 months after induction of insulin therapy. Skin biopsy of the atrophic site revealed inflammatory changes and adipocyte atrophy. Changing the type of insulin and injection site relieved the fat atrophy. Although insulin-induced lipoatrophy was a common complication before the development of human insulin, it is now rare. The immunological reaction to the insulin product, as in conventional impure insulin-induced lipoatrophy, seemed to be involved in the etiology of lipoatrophy in this case.

Adipose Tissue↗
PubMed1998

Silent thyroiditis after excision of a thymoma.

A 61-year-old man developed thyrotoxicosis after excision of a thymoma. His laboratory examination showed an increased level of thyroid hormone and a low thyroidal iodine uptake. No thyroidal autoantibody was detected. With the diagnosis of silent thyroiditis, he was treated with propranolol. He became euthyroid after 2 months. Thymoma often accompanies an autoimmune disease as a paraneoplastic syndrome, and an immunological mechanism is thought to be involved in the onset of silent thyroiditis. This case suggests the involvement of an immunological mechanism in the pathogenesis of silent thyroiditis.

Humans↗
PubMed1998

Pulmonary Mycobacterium avium disease in a young patient with idiopathic CD4+ T lymphocytopenia.

A case of pulmonary Mycobacterium avium (M. avium) disease associated with idiopathic CD4+ T lymphocytopenia is reported. A rapidly growing pulmonary nodule was detected on a chest roentgenogram in a young man. Bronchoscopic examination revealed M. avium infection. Hematological studies showed a low CD4+ cell count in the absence of any identifiable immunodeficiency, including human immunodeficiency virus (HIV) infection. With the combination of chemotherapy and surgery, he had a good clinical outcome. Idiopathic CD4+ T lymphocytopenia should be considered in patients with unexplained opportunistic infection.

Adult↗
PubMed1998

Computer-aided diagnosis for detection of interstitial opacities on chest radiographs.

OBJECTIVE: Our objective was to evaluate the impact of a computer-aided diagnostic scheme on radiologists' interpretations of chest radiographs with interstitial opacities by performing an observer test using receiver operating characteristic (ROC) analysis. MATERIALS AND METHODS: Twenty chest radiographs with normal findings and 20 chest radiographs with abnormal findings were used. Each radiograph was divided into four quadrants. One hundred twenty-nine quadrants (80 normal and 49 abnormal quadrants) were used for testing because we excluded 31 equivocal quadrants. Sixteen independent observers (10 residents and six attending radiologists) participated in this study. The radiologists' performance without and with computer assistance, which indicated cases with normal and abnormal findings by various markers, was evaluated by ROC analysis. RESULTS: The diagnostic accuracy of the observers improved by a statistically significant magnitude when computer-aided diagnosis was used. Thus, the values for the area under the ROC curve obtained with and without the computer-aided diagnostic output were .970 and .948 (p = .0002), respectively, for all observers; .969 and .943 (p = .0006), respectively, for the residents' subgroup; and .972 and .960 (p = .162), respectively, for the attending radiologists' subgroup. The value for the area under the ROC curve for the computerized scheme by itself was .943. CONCLUSION: Our computer-aided diagnostic scheme can assist radiologists in the diagnosis or exclusion of interstitial disease on chest radiographs.

Adolescent↗
PubMed1998

Effect of mitochondrial DNA variation on carcass traits of Japanese Black cattle.

Japanese Black fattening steers were used to examine relationships between carcass traits and mitochondria displacement loop (D-loop) variations. The D-loop region of Japanese Black cattle was sequenced and revealed 26 mitochondrial haplotypes defined by 25 polymorphic sites. The haplotypes were classified into five mitochondrial types (type 1 to 5) using the unweighted pair-group method with arithmetic means. Carcass weight, longissimus muscle area (LMA), rib thickness, subcutaneous fat thickness, yield estimate, and beef marbling score (BMS) were compared among five mitochondrial types with BLUP procedures. Significant differences between mitochondria types were detected for LMA and BMS. Difference (P < . 05) was observed between mitochondrial types 2 and 4 for LMA. There was a highly significant difference (P < .01) in BMS between types 2 and 4. Difference (P < .05) was also found between types 1 and 4 on BMS. These results suggest that cytoplasmic genetic effects are important sources of variation for carcass traits in Japanese Black cattle.

Animals↗
PubMed1998

Nitric oxide is produced via 5-HT1B and 5-HT2B receptor activation in human coronary artery endothelial cells.

The aim of this study is to clarify the serotonin (5-HT) receptor subtypes responsible for 5-HT-induced nitric oxide (NO) production in cultured human coronary artery endothelial cells (HCAECs). Reverse transcription-polymerase chain reactions revealed that HCAECs possessed only 5-HT1B and 5-HT2B receptor mRNAs. 5-HT (0.001-10 mumol/L) induced nitrite production from HCAEC. A selective 5-HT1B/1D agonist sumatriptan (0.01-10 mumol/L) caused nitrite production. A selective 5-HT2 agonist (+/-)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane hydrochloride (DOI, 0.01-10 mumol/L) also mimicked the effect of 5-HT. The 5-HT-induced nitrite production was completely inhibited by the nonselective 5-HT1/2 antagonist methiothepin (0.1 mumol/L), but not by the 5-HT2A/2C antagonist ketanserin (0.1 mumol/L). Each of these agonists evoked the elevation of intracellular Ca2+ concentration in HCAECs. These findings suggest that 5-HT-induced NO production is mediated by both of 5-HT1B and 5-HT2B receptor activation in HCAECs. Thus, the 5-HT-evoked endothelium-dependent relaxation of human coronary arteries in vivo might be evoked by net effects of the activation of these receptor subtypes.

Calcium↗
PubMed1998

[A cooperative study on concomitant with low-dose divided administration of cisplatin (CDDP) and sustained drip infusion of 5-fluorouracil (5-FU) for unresectable advanced gastric cancer. Osaka Cisplatin Gastric Cancer Study Group].

For patients with unresectable gastric cancer registered between July 1994 and September 1995, the following dosage regimen was examined: a drip infusion of cisplatin (CDDP) at 7 mg/m2/day for 5 consecutive days and 2-day withdrawal a week for 3 weeks with concomitant sustained drip infusion of 5-FU at 300 mg/m2/day for 21 days. The whole cycle was repeated again after 2-week withdrawal. The antitumor effect was seen in 39.4% among 33 cases. With respect to histological classification, there was no difference in appearance of the effect between the moderately differentiated type at 62.5% and the low-differentiated type at 42.9%. The cases which became resectable after the administration included those in which the tumor disappeared completely in the resected specimens. As adverse reactions encountered in the cases above Grade 3, anorexia, nausea and vomiting and diarrhea were seen as clinical symptoms in 10, 5.3 and 11.8%, respectively. As laboratory test values, decrease in hemoglobin, leukocytopenia and thrombocytopenia were seen in 16.7, 15.8 and 5%, respectively, while renal or liver dysfunction did not occur. This dosage regimen was considered useful for unresectable advanced gastric cancer, although myelosuppression should be watched carefully.

Adult↗
PubMed1998

Evaluation of thrombopoiesis in thrombocytopenic disorders by simultaneous measurement of reticulated platelets of whole blood and serum thrombopoietin concentrations.

To evaluate thrombopoiesis in thrombocytopenic disorders, we simultaneously determined reticulated platelet counts in whole blood by FACScan flow cytometry and serum thrombopoietin (TPO) concentrations by a sensitive sandwich ELISA. The subjects were 40 healthy volunteers and 45 thrombocytopenic patients. In idiopathic thrombocytopenic purpura (ITP), the percentage of reticulated platelets was significantly elevated (5.61 +/- 2.02%: mean +/- SD) relative to normal controls (2.17 +/- 0.90%), but serum TPO concentrations (1.91 +/- 1.27 fmol/l) did not differ significantly from the normal range (1.43 +/- 0.62 fmol/l). The patients with aplastic anemia (AA) had decreased reticulated platelet counts and markedly increased serum TPO concentrations (13.65 +/- 10.64 fmol/l). In thrombocytopenic patients with liver cirrhosis (LC), the absolute number of reticulated platelets (1.65 +/- 1.11 x 10(9)/l) decreased similarly that in AA. However, serum TPO concentrations (1.38 +/- 0.50 fmol/l) did not increase in contrast to AA. Our findings suggested a possible dual mechanism of thrombocytopenia in LC; that is, thrombocytopenia in LC results from the decreased TPO production primarily in the liver adding to an increase in platelet sequestration in the spleen.

Anemia, Aplastic↗
PubMed1998

[Clinical application of ischemic microwave coagulation therapy for malignant liver tumor].

By means of ischemic coagulation of the hepatic artery and portal vein in a microwave coagulation experiment of in vivo swine [correction of bovine] liver, we confirmed approximate doubling of the coagulation diameter compared to the usual coagulation. Based on this fact, for treatment of patients with metastatic liver tumor, we developed an ischemic percutaneous microwave tumor coagulation method using IVR method and applied it in one case, and performed laparotomy microwave tumor coagulation in three cases. We performed the ischemic percutaneous microwave tumor coagulation method on one of the cases. Coagulation was performed for one minute at a dose of 100 W for treatment of metastatic liver tumor of 2 cm in diameter via laparotomy. The postoperative CT showed an extensive coagulation larger than 3 cm. A 2 cm liver tumor was coagulated under balloon ischemia of the hepatic vein and hepatic artery for 13 minutes at a dose of 60 W. The maximum coagulation diameter was 5 cm. Extensive coagulation was possible with percutaneous microwave tumor coagulation through ischemia.

Animals↗
PubMed1998

[Microwave hepatic tumor coagulation therapy during stoppage of hepatic blood flow using balloon catheters].

The usefulness of microwave hepatic tumor coagulation therapy (MTC) with stoppage of hepatic blood flow using a balloon catheter was assessed. By placing a 5-French balloon catheter in a hepatic artery and 6-French balloon catheter in a hepatic vein, hepatic arterial and portal venous flow of the liver segment including the tumor was interrupted. The effects of balloon occlusion were evaluated by CT during arterial portography. MTC with stoppage of hepatic flow was performed for two patients with metastatic liver tumor 2 cm in diameter. Enhanced CT obtained after MTC showed no enhancement of the tumor, indicating complete necrosis. There were no complications and the two patients were discharged within 4 days after MTC. MTC with stoppage of hepatic blood flow is effective for treatment of hepatic metastatic tumor.

Catheterization↗