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Biomedical subjects

H Sakamoto

Publications and source records attributed to H Sakamoto.

At least 685 records · Page 38Linked to original sources
PubMed1990

[Antibacterial activity of norfloxacin on methicillin-resistant Staphylococcus aureus. Comparison with oral antibacterial agents].

Minimum inhibitory concentrations (MIC) of norfloxacin (NFLX) to 133 strains of methicillin-resistant Staphylococcus aureus (MRSA) isolated from clinical patients were investigated and compared with those of minocycline (MINO), erythromycin (EM), amoxicillin (AMPC), cefaclor (CCL) and fosfomycin (FOM). MIC90 of these drugs were 3.13 micrograms/ml with NFLX, 0.39 micrograms/ml with MINO, greater than 100 micrograms/ml with EM, 50 micrograms/ml with AMPC, greater than 100 micrograms/ml with CCL and greater than 100 micrograms/ml with CCL and greater than 100 micrograms/ml with FOM. MIC distribution patterns with 2 peaks were recognized with EM and FOM. Of 55 strains resistant to all of EM, AMPC, CCL and FOM, 50 and 54 strains were well susceptible to NFLX and MINO, respectively. The present investigation demonstrated relatively potent antibiotic effect of NFLX against MRSA. Considering the safety of NFLX to children which have been confirmed and reported separately, it can be concluded that NFLX is a useful oral antimicrobial drug in the treatment of children with MRSA infections.

Administration, Oral↗
PubMed1990

[A resected case of mediastinal tuberculous lymphadenitis with pericostal tuberculosis].

A case of 22-year-old female with mediastinal tuberculous lymphadenitis and pericostal tuberculosis was reported. Her complaint was right chest pain and subcutaneous mass on the right chest wall. Chest contrast CT showed right paratracheal lymph node swelling with central low density area and surrounding rim enhancement, which has been reported as typical characteristics of mediastinal tuberculous lymphadenitis. Pigeon-egg sized subcutaneous mass with fluctuation was palpable on the right sternal border and the smear of its content showed acid-fast bacilli. In spite of two months therapy with antituberculous drugs, both masses were unchanged in size. The lesions resected surgically, were both encapsulated abscesses containing yellowish pus, and microscopic examination of these specimen disclosed the finding of tuberculosis. Mycobacterium tuberculosis was cultured from contents of both masses. After nine months of anti-tuberculous therapy, no sign of recurrence is observed until now. Both masses were discontinuous and the possibility of lymphangitic spread of organism was speculated as its etiology.

Adult↗
PubMed1989

A secondary structure at the 3' splice site affects the in vitro splicing reaction of mouse immunoglobulin mu chain pre-mRNAs.

The expression of the IgM (immunoglobulin mu) heavy chain gene is known to be regulated at the post-transcriptional level. The two isoforms, the membrane-bound and secreted forms, are generated from the same gene by alternative processing at the 3' end of the primary transcript. The processing reactions involved are polyadenylation at the upstream poly(A) site (for the secreted form) and polyadenylation at the downstream poly(A) site coupled with splicing between exon C4 and exon M1 (for the membrane-bound form). The regulatory mechanism underlying these differential processing reactions is still not well understood. We investigated the splicing reaction between exon C4 and exon M1 in a HeLa nuclear extract using model transcripts containing the 5' and 3' splice sites of the C4-M1 intron. We found that the 3' splice site of the C4-M1 intron is sequestered in a stem-loop structure, which inhibits the splicing reaction in vitro. The inhibition by the stem-loop structure was also observed with a mouse lymphoma extract.

Animals↗
PubMed1989

High incidence of coamplification of hst-1 and int-2 genes in human esophageal carcinomas.

We analyzed the alteration of the hst-1 and int-2 genes in 36 cases of esophageal squamous cell carcinoma, 42 cases of gastric adenocarcinoma, and 52 cases of colorectal adenocarcinoma. Coamplification of the hst-1 and int-2 genes was observed in 19 of 36 esophageal carcinomas (52%), 16 of 34 primary tumor tissues (47%), and 10 of 10 metastatic tumors (100%). The degree of amplification ranged from 4- to 8-fold. The incidence of hst-1 and int-2 gene coamplification was significantly higher in male patients than that in female patients (P less than 0.05). The coamplification of the hst-1 and int-2 genes had a tendency to correlate with clinical stage. The progesterone receptor gene, which is mapped to chromosome 11 at band q21-23, was not amplified in these esophageal carcinomas. Coamplification of the hst-1 and int-2 gene does not seem to imply increased numbers of chromosome 11, and the hst-1 and int-2 genes appear to be in same amplification unit on chromosome 11 at band q13. No coamplification of the hst-1 and int-2 genes was detected in gastric carcinomas and colorectal carcinomas. These results suggest that amplification of chromosomal locus of the hst-1 and int-2 genes might participate in carcinogenesis, in progression, and particularly in metastasis of esophageal carcinomas.

Blotting, Southern↗
PubMed1989

UCHL1-positive extranodal lymphoma resembling multiple lymphomatous polyposis of the gastrointestinal tract.

Histopathologic and immunohistochemical studies were done on paraffin sections from a patient with alimentary tract lymphoma resembling multiple lymphomatous polyposis of the gastrointestinal tract (MLP). Diffuse, but not follicular, proliferation of medium-sized lymphoid cells was noted in the polypoid lesions of the alimentary tract, peripancreatic lymph nodes, spleen, liver, and bone marrow. These cells possessed a T-cell-related antigen (UCHL1), but were negative for the B-cell-related and myeloid cell-related antigens examined. Because neoplastic cells in MLP are usually of B-cell origin, the current case will provide important information on the relation between phenotypes and morphologic patterns of proliferation.

Aged↗
PubMed1989

[Clinical experiences of LAK therapy in patients with hepatocellular carcinoma].

A patient with hepatocellular carcinoma (HCC) was treated with newly established adoptive immunotherapy using LAK cells (LAK therapy) together with transcatheter arterial embolization therapy (TAE). This patient responded well, and the therapeutic efficacy still continues 6 months after the therapy. Since the efficacy of LAK therapy does not last long, it is recommended that LAK therapy should be employed in combination with such therapeutic maneuvers as TAE or anticancer drugs in patients with HCC.

Aged↗
PubMed1989

Parathyroid hormone 1-34, but not 3-34 or 7-34, transiently translocates protein kinase C in cultured renal (OK) cells.

While protein kinase C (PKC) appears to play a role in the action of PTH in renal cells, direct evidence of activation by PTH is lacking. Rat PTH (1-34) caused a rapid, transient translocation of PKC in opossum kidney (OK) cells from a basal value of 0.09 to maximum of 0.24 at 10-15 sec. Both the time course and dose-response relationship of translocation matched a corresponding increase in cytosolic Ca2+. In contrast, PTH activation of cAMP-dependent protein kinase (PKA), while also rapid, was greater in magnitude (0.10 to 0.50), persistent, and occurred at a threshold level of 3 x 10(-10)M PTH, compared to 10(-8)M for PKC. Neither bPTH(3-34) nor bPTH(7-34) activated either protein kinase, while both antagonized rPTH(1-34)-induced PKC translocation more effectively than PKA activation. These differential effects of PTH agonist and antagonists further support the suggestion that PTH acts through two signal transduction mechanisms in which one or more receptors is linked in distinct ways to adenylate cyclase and phospholipase C.

Animals↗
PubMed1989

Fine-needle aspiration cytology of pheochromocytoma-ganglioneuroma of the organ of Zuckerkandl.

Fine-needle aspiration (FNA) cytologic and immunocytochemical findings of a rare combined pheochromocytoma-ganglioneuroma developing in a 48-yr-old Japanese man in the organ of Zuckerkandl are described. This is the first report of a combined pheochromocytoma-ganglioneuroma of the organ of Zuckerkandl. FNA cytology showed typical cytologic findings of these two components similar to those described individually in fine-needle aspirates of these neoplasms. The neoplastic cells showed positive reactions for vasoactive intestinal polypeptide, neuron-specific enolase, and S-100.

Biopsy, Needle↗
PubMed1989

Immunological functions and phenotypes of peripheral blood lymphocytes from human T-cell leukemia virus-I carriers.

We studied immunological functions of peripheral blood lymphocytes (PBL) from human T-cell leukemia virus type I (HTLV-I)-seropositive healthy carriers in vitro. Proliferative responses of PBL to T-cell and B-cell mitogens such as concanavalin A (Con A), pokeweed mitogen (PWM), and Staphylococcus aureus Cowan I (SAC) were moderately impaired in HTLV-I carriers compared with normal controls. Immunoglobulin (Ig)-producing activity of PBL stimulated with B-cell mitogens were also impaired in HTLV-I carriers. However, cytotoxic T-cell activity induced by in vitro culture was not impaired but slightly increased in HTLV-I carriers. Natural killer-cell activity was only slightly decreased. By a flow cytofluorometric analysis of the cell surface phenotypes of PBL, the percentage and the mean fluorescence intensity (MFI) of CD 3-positive cells and CD 4-positive cells were significantly decreased in HTLV-I carriers. The percentage and the MFI of CD 8-positive cells was not changed. The percentage and the MFI of CD 25-positive cells were increased. These results suggest that some immunological abnormalities are already present in HTLV-I carriers and such abnormalities have some roles for the leukemogenesis from the infection of the HTLV-I into adult T-cell leukemia (ATL).

Adolescent↗
PubMed1989

Neurotransmitter regulation of cytosolic calcium in osteoblast-like bone cells.

The nervous system may play a role in regulation of bone metabolism. The effects of norepinephrine(NE), vasoactive intestinal peptide(VIP), and ATP on cytosolic Ca2+ were assessed in a rat osteoblast-like osteosarcoma cell line (UMR-106) responsive to PTH. All three transmitters transiently increased Ca2+, with ATP much greater than PTH greater than NE = VIP, and then caused sustained increases in Ca2+. The ATP-induced transient resulted from mobilization of intracellular Ca2+ store, while NE and VIP-induced transients also involved influx of Ca2+. Later sustained increases by all agonists were dependent upon extracellular Ca2+. Release of intracellular Ca2+ by ATP was associated with a marked increase in IP3 but without a significant change in cAMP. NE, VIP, and ATP, through regulation of Ca2+ metabolism, may be involved in various osteoporotic conditions.

Adenosine Triphosphate↗
PubMed1989

A testis-specific antigen of the C57BL/6 mouse.

Spleen cells from female mice of the C57BL/6 strain iso-immunized with an homogenate from 3-week-old mice testis were fused with P3U1 cells. After cloning, two hybridomas, producing IgM, were obtained. Tissue specificity of the monoclonal antibody (Moab) in ascitic fluid was investigated by indirect immunofluorescence. Moab 1A1 reacted specifically with the cytoplasm of spermatogonia, spermatocytes and spermatids, but not with spermatozoa. Testicular antigen recognized by Moab 1A1 (Moab1A1-TA) was prepared by tissue sonication and then subjected to gel filtration. Moab1A1-TA detected in the void volume by ELISA was analyzed by SDS-PAGE and Western blotting. Immuno-staining of membrane filters revealed a broad area within the 45-205 kD range. Moab1A1-TA was treated with proteolytic enzymes, but no changes were observed after Western blotting. Thus, Moab1A1-TA was further digested by peptidases and glycolytic enzymes, electrophoresed using cellulose acetate membranes and immuno-stained with Moab 1A1. Evidence obtained from these experiments strongly suggests that Moab1A1-TA consists of an acidic peptide and a carbohydrate molecule. The antigenicity would be included in the carbohydrate epitope. Moreover, partial digestion of Moab1A1-TA by keratanase indicates that the lacto-series structure is included in the antigenic carbohydrate moiety.

Animals↗
PubMed1989

Substance P-immunoreactive elements in laminae I and II of the chicken spinal cord: a light- and electron-microscopic study.

Substance P (SP)-immunoreactive (IR) elements were studied in laminae I and II of the chicken spinal cord in conjunction with an anti-SP monoclonal antibody at light- and electron-microscopic levels by means of the indirect antibody peroxidase-antiperoxidase technique. At the light-microscopic level, SP-IR elements were most intensely observed in the dorsolateral portion of the dorsal horn, laminae I and II. Electron-microscopically, SP-IR boutons contained large spherical dense-cored vesicles (diameter range: 60-125 nm) and spherical clear vesicles. They were subdivided into two groups: large SP-IR boutons, which were the central terminals in synaptic glomeruli, and small SP-IR boutons. In the synaptic glomerulus, two kinds of non-IR presynaptic profiles made axo-axonic synapses with the SP-IR central terminal: one was the presynaptic profile containing pleomorphic clear vesicles and the other was the presynaptic profile containing large dense-cored vesicles. A 'septate junction'-like structure was observed between large SP-IR boutons in synaptic glomeruli. The present results suggest that SP-containing primary afferents are modulated presynaptically by two different neurotransmitter or modulator systems.

Animals↗
PubMed1989

Comparison of enzyme-linked immunosorbent assay (ELISA) with dot hybridization using 32P- or 2-acetylaminofluorene (AAF)-labelled cDNA probes for the detection and characterization of beet necrotic yellow vein virus.

Beet Necrotic Yellow Vein Virus (BNYVV) was detected by enzyme-linked immunosorbent assay (ELISA) and RNA/DNA dot hybridization using either radiolabelled or non-radioactive probes. Dot hybridization specifically distinguished isolates that could not be distinguished by ELISA. The detection thresholds for ELISA, hybridization with non-radioactive probes and hybridization with radiolabelled probes were 2 ng, 0.2 ng, 0.02 ng of purified virus, respectively. Dot hybridization with non-radioactive probes could be performed on crude infected beet root extracts, thus providing a useful tool for monitoring BNYVV infection and for routine testing in plant breeding programs.

2-Acetylaminofluorene↗