Biomedical subjects

A Sakamoto

Publications and source records attributed to A Sakamoto.

At least 163 records · Page 9Linked to original sources

PubMed1996

T-cell receptor repertoire of infiltrating T cells in lachrymal glands, salivary glands and kidneys from alymphoplasia (aly) mutant mice: a new model for Sjögren's syndrome.

Alymphoplasia (aly) mice are thought to provide a new model for systemic Sjögren's syndrome (SS), since they reveal remarkable infiltration of mononuclear cells into salivary glands, lachrymal glands and kidneys, and show histological findings similar to those in patients with SS. Cell transfer experiments demonstrate that T cells induce the infiltration of mononuclear cells into several tissues in aly mice. To analyse the pathogenesis of cell infiltration in various tissues, we examined T-cell receptor (TCR) V beta usage of T cells in salivary glands, lachrymal glands and kidneys from aly mice, using family-polymerase chain reaction (PCR) and PCR-single-strand conformation polymorphism (SSCP) methods. The results of SSCP demonstrated that the infiltrating T cells in the three organs expanded clonally, suggesting that they proliferate by antigen-driven stimulation. Some TCR V beta genes (V beta 1, 3, 6, 11, 12, 16) were commonly used in salivary glands, lachrymal glands and kidneys, while the V beta 7 gene was specifically expressed in kidneys. SSCP also showed that there were a few shared T-cell clones (V beta 3- and V beta 6-positive cells) among the three tissues. Indeed, sequence analysis of accumulated T cells showed that a conserved amino acid (leucine) at position 98 in the TCR V beta complementary determining region (CDR) 3 was detected in all organs at high frequency (41-57%) and the amino acid sequence motif (LG) was specifically conserved at a frequency of 32% in the three organs. In conclusion, T cells that infiltrate into lachrymal glands, salivary glands and kidneys of aly mutant mice might recognize shared common epitopes in all three organs and a kidney-specific antigen.

Animals↗

PubMed1996

Epiduroscopic changes in patients undergoing single and repeated epidural injections.

Using a superfine fiberscope with an outer diameter of 0.75 mm, the effect of repeated injections through a single epidural catheter on the epidural space was examined in 18 patients. The subjects were divided into a control group of 10 patients who had not previously received epidural anesthesia (EA) and an EA group of 8 patients who had received repeated EA with 4-6 mL 0.25% bupivacaine through an epidural catheter, two to three times per day for 7-14 days. The epidural space was observed through a fiberscope passed through a 17-gauge Tuohy needle. The epidural space was occupied by large masses of fat, and the blood vessels and connective tissue were confirmed. Adverse reactions in the epidural tissue, such as hemorrhage or congestion with engorgement, were observed in four patients in the EA group. Five patients in the EA group experienced pain when the fiberscope was inserted into the epidural space. These investigations show that continuous EA might be followed by a high incidence of nonspecific epidural changes. Superfine fiberscope may be useful in the detection or diagnosis of local epidural reaction.

Adult↗

PubMed1996

Immunohistochemical analysis of endometrial adenocarcinoma for bcl-2 and p53 in relation to expression of sex steroid receptor and proliferative activity.

In order to clarify the factors that affect growth of endometrial carcinoma, immunohistochemical analyses of bcl-2, p53, sex steroid receptors, and Ki-67 were performed in 35 cases of endometrial carcinoma (32 endometrioid and three clear-cell carcinomas). Correlation of antigen expression with clinicopathological features was analyzed. Expression of bcl-2 was found in 58.8, 33.3, and 20.0% of grade 1 (G1), grade 2 (G2), and grade 3 (G3) endometrial carcinomas, respectively. Estrogen receptor (ER) was observed in 70.6, 22.2, and 0% of G1, G2, and G3 cases (p < 0.01), respectively. In contrast, expression of p53 was found in 5.8, 33.3, and 60.0% of G1, G2, and G3 cases, respectively. The labeling index of Ki-67 correlated with p53 overexpression (p < 0.01). Lymph node metastases were observed in 6.6 and 5.5% of ER- and PR (progesterone receptor)-positive carcinomas, whereas metastases were observed in 44.4 and 53.3% of ER- and PR-negative carcinomas, respectively (p < 0.05). Lymph node metastases were observed in 50.0% of p53-positive carcinomas, whereas metastases were observed in 22.2% of p53-negative carcinomas (p < 0.05). These results suggest that bcl-2 expression in endometrial carcinomas is regulated in a hormone-dependent manner. Expression of bcl-2 may occur more frequently in estrogen-related, low-grade endometrial carcinomas, whereas p53 overexpression is found more often in endometrial carcinomas in estrogen-unrelated, high-grade endometrial carcinomas with prominent proliferative activity and a high frequency of lymph node metastases.

Adenocarcinoma↗

PubMed1996

A prospective study of bronchoscopy for endotracheobronchial tuberculosis.

To clarify the role of bronchoscopy for endotracheobronchial tuberculosis (EBTB), we performed a prospective study in 45 patients with active pulmonary tuberculosis, in 15 (33%) of whom bronchoscopic findings related to EBTB were seen. The findings were classified into six types:edematous hyperemic, submucosal nodule, ulcerative (shallow and deep), polypoid, cicatrical, and compression type. Each of these types was related to the healing process and outcome after antituberculosis chemotherapy. Serial bronchoscopy revealed that lesions less advanced than the deep ulcerative type responded to chemotherapy; the deep ulcerative and polypoid types progressed to cicatrical bronchostenosis despite chemotherapy. In the follow-up of patients with lesions of the deep ulcerative and polypoid types, serial bronchoscopy after chemotherapy is recommended; these patients also require adjunctive therapy to prevent cicatrical bronchostenosis.

Biopsy↗

PubMed1996

[Clinical significance of soluble interleukin-2 receptor levels in the cerebrospinal fluid in patients with adult T-cell leukemia complicated with meningeal infiltration].

We measured soluble interleukin-2 receptor (sIL-2R) levels in the cerebrospinal fluid (CSF) of patients with hematological malignancies especially, adult T-cell leukemia (ATL) and non-Hodgkin's lymphoma (NHL) with or without meningeal infiltration. CSF levels of sIL-2R were significantly higher in patients with ATL and NHL with meningeal infiltration than in patients with both diseases without meningeal infiltration. The sIL-2R levels in CSF were elevated in 4/4 ATL patients (100%) and 3/13 NHL patients (23%) with meningeal infiltration. CSF levels of sIL-2R from ATL patients with meningeal infiltration had a tendency to elevate in correlation with numbers of mononuclear cells and lactic dehydrogenase (LDH) in CSF. However, these had no correlation with serum levels of sIL-2R. Therefore, sIL-2 levels in CSF may be useful in the diagnosis of meningeal infiltration in patients with ATL, are probably specific markers for meningeal infiltration of ATL.

Adolescent↗

PubMed1996

[Selective epidural nerve root block using a superfine fiberscope].

A 65 yr-old male with severe scar pain on his right lower abdomen underwent selective nerve block through epidural space using a superfine fiberscope. A12-gauge Tuohy needle (internal diameter 2.2 mm) was inserted at the intervertebral space of Th12-L1. The fiberscope (external diameter 1.1 mm) was introduced through the needle and the epidural space was observed. When the dura mater of Th12 nerve root level was seen, the patient had pain on the scar area. Then 2% lidocaine 1.5 ml and 60% megumine sodium amidotrizoate 1.5 ml were slowly injected. Soon after injection of anesthetic, analgesia area (Th11-L1) was obtained, and Th12 nerve root was identified by X ray. Epidural blockade using a superfine fiberscope seems to be one of the useful and reliable methods for the selective nerve blockade.

Aged↗

PubMed1996

[Surgical treatment for active infective endocarditis : septic embolization and mycotic aneurysms].

From 1978 through 1995, surgical treatment for active infective endocarditis (native valve) was performed in 17 patients. The indication for operation at the active phase was progressive heart failure in 5 (A-group) and uncontrolled infection in 12 (B-group). Operative findings showed vegetations in all cases, perforations of the valve in 6, rupture of tendon in 2, and annular abscesses in 2. One patient in B-group died 14 days after the operation with postoperative mediastinitis and sepsis. There was no perioperative complications in A-group. In B-group before operations 8 patients (66.7%) has an embolic event before operations. The anatomic sites of embolization were the central nervous system (3 patients), viscera (2 patient) and peripheral arteries (3 patients). And after operation there were 2 mycotic aneurysms of the hepatic artery and the popliteal artery, and 1 pyogenic spondylitis. We conclude that the risk of embolization is high in patients undergoing surgery at active phase of infective endocarditis because of uncontrolled infection ; thus, such patients should be carefully monitored for emboli and mycotic aneurysms.

Adult↗

PubMed1996

[Helical CT guided lumar sympathetic ganglion block].

Helical CT scan was used as a guide for lumbar sympathetic ganglion block. By examining anatomical location of the block site with the sequential fluoroscope pictures of helical CT scan, we succeeded in the block of sympathetic ganglion easily. It is possible by the use of sequential CT picture to reduce the risk of puncturing essential organ such as the kidney, descending aorta, inferior vena cava and so on. Moreover, we can expect that application of helical CT scan will raise the success rate of block and will decrease the time necessary for the performance of block.

Autonomic Nerve Block↗

PubMed1996

[Soluble interleukin-2 receptor and macrophage colony-stimulating factor (M-CSF) in cerebrospinal fluid in patients with hematological malignancies: clinical significance in adult T-cell leukemia with meningeal infiltration].

We measured soluble interleukin-2 receptor (sIL-2R) and macrophage colony-stimulating factor (M-CSF) levels in the cerebrospinal fluid (CSF) of patients with hematological malignancies with or without meningeal infiltration and meningitis. Levels of sIL-2R and M-CSF in the CSF of adult T-cell leukemia (ATL) patients with meningeal infiltration were significantly higher than those of ATL patients without meningeal infiltration and non-ATL patients with meningeal infiltration. There was a significant positive correlation between sIL-2R levels and numbers of mononuclear cells in CSF of ATL patients with meningeal infiltration. However, M-CSF levels did not correlate with numbers of mononuclear cells. There was no correlation between CSF and serum levels of sIL-2R. There was also no correlation between sIL-2R and M-CSF in the CSF. Therefore, sIL-2R and M-CSF levels in the CSF may be useful in the diagnosis of meningeal infiltration in patients with ATL. In particular sIL-2R may be a sensitive marker.

Biomarkers, Tumor↗

PubMed1996

[Anemia due to chronic lead poisoning].

We report a case of anemia due to chronic lead poisoning. A 46-year-old female was admitted to our hospital because of general fatigue and anemia. A peripheral blood smear showed basophilic stippling. There was basophilic stippling and nuclear dysplasia of erythroblasts in the bone marrow. Laboratory findings were as follows: RBC 296 X 10(4)/microliter, Hb 8.5 g/dl, blood lead concentration 67 micrograms/dl, urinary lead concentration 309 micrograms/l, blood delta-ALA dehydrase 0.03 mumol/ml, urinary delta-ALA 25.2 mg/l, urinary coproporphyrin 8,810 micrograms/g.Cr, and blood protoporphyrin 612 micrograms/dl. Chronic lead poisoning was diagnosed and she was treated with Ca-EDTA.

Anemia↗

PubMed1995

Truncation of the receptor carboxyl terminus impairs membrane signaling but not ligand binding of human ETB endothelin receptor.

Human ETB endothelin receptor (hETBR) is a heptahelical G-protein-coupled receptor consisting of 442 amino acids whose carboxyl (C)-intracellular region has four and twelve sites for potential palmitoylation and phosphorylation, respectively. In order to elucidate the functional roles of these modification sites, we constructed a series of C-terminal truncated hETBRs and expressed them in Ltk- cells. All the truncated hETBRs showed ligand-binding profiles similar to those of the wild-type hETBR. The truncated receptors holding Cys-402 retained both normal intracellular calcium ([Ca2+]i) response and its rapid desensitization; however, the deleted receptors lacking Cys-402 failed to induce the [Ca2+]i response. These results showed that Cys-402 of hETBR is necessary for its intracellular calcium signaling and that at least ten of twelve putative phosphorylation sites are irresponsible for the agonist-induced desensitization.

Amino Acid Sequence↗

PubMed1995

Limited TCR repertoire of infiltrating T cells in the kidneys of Sjögren's syndrome patients with interstitial nephritis.

To analyze the mechanism of interstitial nephritis in patients with Sjörgren's syndrome (SS), we examined the TCR repertoire of infiltration T cells in kidney, labial salivary glands, and PBLs using a PCR. The repertoire of the TCR V beta gene on infiltrating T cells from the kidneys of SS patients was more restricted than those on infiltrating T cells in labial salivary glands and PBL. The TCR V beta 2 gene was expressed predominantly in six of seven (86%) SS patients. Junctional sequences of cDNAs encoding the V beta 2 gene on infiltrating T cells in the kidneys of five SS patients showed that some of the cells expanded clonally, indicating Ag-driven stimulation rather than superantigen-induced proliferation. The same V beta 2 clones in the kidney were not detected in labial salivary glands of the same SS patients; the conserved amino acid (arginine at position 96) in the CDR3 region of the V beta 2 gene was found at a frequency of 48.0% in the kidney, whereas it was detected in only 15.4% of the clones in lips. In conclusion, these findings suggest the possibility that T cells that infiltrate the kidneys of SS patients with interstitial nephritis might recognize different autoantigens than those that infiltrate labial salivary glands.

Amino Acid Sequence↗

PubMed1995

Selective reduction of T cells bearing invariant V alpha 24J alpha Q antigen receptor in patients with systemic sclerosis.

A novel subset of T cells characterized by the expression of an invariant T cell antigen receptor (TCR) encoded by V alpha 24J alpha Q gene segments was investigated in patients with systemic sclerosis (SSc). Polymerase chain reaction analysis demonstrated that the V alpha 24 TCR repertoire was selectively used in CD4-CD8- double-negative T cells both in patients and in healthy individuals, while almost all families of TCR V alpha were expressed in single-positive T cell fractions. The V alpha 24+ double-negative T cells were increased by approximately fivefold in patients. However, sequence analysis clearly showed significant differences in the V alpha 24 TCR repertoire dominating in patients and healthy donors. In healthy individuals, the invariant V alpha 24J alpha Q was expanded and comprised 20-50% of the total TCR-alpha, while their selective reduction was observed in SSc patients who also showed expansion of invariant V alpha 24 TCR other than V alpha 24J alpha Q. Analogous to murine invariant V alpha 14J alpha 281 TCR, these results suggest that T cells with invariant V alpha 24J alpha Q TCR would function as regulatory T cells, whereas T cells bearing other invariant V alpha 24 TCR in SSc patients could be autoaggressive T cells in nature.

Asian People↗

PubMed1995

The distribution of TM-316-associated surface antigen on polymorphonuclear leucocytes: an immunoelectron microscopic study.

It has been established that MoAb TM-316 recognizes an epitope on leucocytes and specifically inhibits the chemotactic behavior of leucocytes. In the present paper, the distribution of this epitope on the cell surface and in intracellular organelles was studied by immunoelectron microscopy. Leucocytes separated from the blood of healthy men and from synovial fluid from patients suffering from rheumatoid arthritis were used. They were fixed with a mixture containing paraformaldehyde, glutaraldehyde and picric acid. As the second antibody, goat anti-mouse IgM conjugated to 10 nm gold colloids was employed. In normal specimens, the epitope was found to some extent on the cytoplasmic membrane of neutrophilic leucocytes, but it was only sparsely distributed on eosinophilic and basophilic leucocytes. On activated neutrophilic leucocytes, obtained from the synovial fluid of rheumatoid arthritis patients, the immunolabeling was markedly increased. The number of sites where the epitope occurs on the surface of leucocytes is thus associated with the cell type, and also with the level of activation of the leucocytes. In order to investigate the processing of the antigen, the intracellular localization of the epitope in the neutrophilic leucocytes was also studied. The epitope recognized by TM-316 was also detected in/on the characteristic granules and Golgi stacks.

Antigens↗

PubMed1995

Structural basis of G protein specificity of human endothelin receptors. A study with endothelinA/B chimeras.

The endothelin (ET) family of peptides acts via two subtypes of guanine nucleotide-binding regulatory protein (G protein)-coupled receptors termed ETA and ETB. ET-1 stimulated cAMP formation in Chinese hamster ovary (CHO) cells stably expressing human wild-type ETA (CHO/hETA cells) while it inhibited cAMP formation in CHO cells expressing human wild-type ETB (CHO/hETB cells), and pharmacological evidence indicated that the opposite effects were due to the selective coupling of each receptor subtype with G alpha s/G alpha i. To find out a receptor domain(s) that determined the selective coupling, a series of chimeric receptors between hETA and hETB was expressed on CHO cells, and the effect of ET-1 on cAMP formation in each cell line was tested. hETA with the replacement of second and/or third intracellular loop (ICLII and/or -III) to the corresponding region(s) of hETB failed to transmit the stimulatory effect of ET-1. hETB with the replacement of ICLIII to the corresponding region of hETA failed to transmit the inhibitory effect of ET-1. A chimeric receptor with ICLII of hETB and with ICLIII of hETA failed to transmit both effects. In cells expressing chimeric receptors with ICLII of hETA and with ICLIII of hETB, ET-1 inhibited cAMP formation while it stimulated cAMP formation when cells were pretreated with pertussis toxin. These results indicated the roles of ICLII and -III of hETR as a major determinant of the selective coupling of hETA and hETB with G alpha s/G alpha i, respectively. We also demonstrated that each receptor subtype expressed on the same cell could work independently, i.e. for hETA to activate G alpha s and for hETB to activate G alpha i, resulting in dose-dependent dual effects of ET-1 on cAMP formation.

Animals↗

PubMed1995

Observation of the pre-steady state process in thermolysin catalysis with a fluorescent displacement probe at low pH.

The pre-steady state process in the thermolysin-catalyzed hydrolysis of Cbz-Gly-Phe-Ala was observed at pH 4.5 by fluorescence stopped-flow method using Dns-Phe as a displacement probe. After the confirmation of the pre-equilibrium hypothesis for the binary interaction, the nonlinear substrate concentration dependence of the apparent kinetic constant for the pre-steady state process was analyzed and an existence of multi-intermediates was proposed.

Amino Acid Sequence↗

PubMed1995

Structure and differential response to abscisic acid of two promoters for the cytosolic copper/zinc-superoxide dismutase genes, SodCc1 and SodCc2, in rice protoplasts.

We determined the 5'-flanking sequences of two nuclear genes (SodCc1 and SodCc2) encoding cytosolic copper/zinc-superoxide dismutase in rice (Oryza sativa L.). Utilizing transient beta-glucuronidase (GUS) reporter assays, functional promoter-GUS analysis was performed in rice protoplasts exposed to the phytohormone abscisic acid (ABA) or the antioxidant sulfhydryl reagent, dithiothreitol (DTT). Transcriptional activities from both SodCc-GUS fusions were stimulated by DTT, which induces the promoter activity of the tobacco SodCc gene [Proc. Natl. Acad. Sci. USA 90 (1993) 3108-3112]. ABA had no effect on SodCcl-GUS expression but specifically induced the gene expression of the SodCc2-GUS fusion. The simultaneous application of ABA and gibberellin A3, however, abolished the enhancing effect of ABA. These results indicated that two rice SodCc promoters differentially respond to externally supplied ABA and that one of the regulatory factors for plant SodCc expression is ABA in addition to cellular redox-modulating antioxidants.

Abscisic Acid↗

PubMed1995

Successful expression in pollen of various plant species of in vitro synthesized mRNA introduced by particle bombardment.

Gold particles coated with beta-glucuronidase (GUS) mRNA with a 5' cap structure that had been synthesized in vitro were introduced, by use of a pneumatic particle gun, into pollen grains of lily (Lilium longiflorum), freesia (Freesia refracta) and tulip (Tulipa gesneriana). A fluorometric assay for the GUS activity indicated that in vitro synthesized GUS mRNA introduced into these pollen cells by particle bombardment was successfully expressed. GUS activity in extracts of the bombarded lily pollen became detectable fluorometrically within 30 min after bombardment, peaked at 6 h, then gradually decreased. This activity changed as a function of the developmental stage of the pollen cell of lily.

Gene Expression↗