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Biomedical subjects

M Fukunaga

Publications and source records attributed to M Fukunaga.

At least 289 records · Page 16Linked to original sources
PubMed1991

Liposome-entrapped calcitonin and parathyroid hormone are orally effective in rats.

We have demonstrated that liposomally entrapped calcitonin (CT) and parathyroid hormone (PTH) can be orally effective in regulating blood calcium. Liposomal CT produced hypocalcemia and liposomal PTH produced hypercalcemia upon oral administration to rats. Specific liposomal formulations were necessary to affect the appropriate decrease and increase in blood calcium concentration. Future extension of these studies may lead to clinically valuable forms of liposomal-peptide preparations.

Animals↗
PubMed1991

Stimulatory effect of thrombin on endothelin-1 production in isolated glomeruli and cultured mesangial cells of rats.

To determine whether endothelin-1 (ET-1) is released in close proximity to its binding sites on glomerular mesangial cells, and also to elucidate the regulatory factors responsible for its release, we measured immunoreactive ET-1 (ir-ET-1) in the incubation media of isolated glomeruli and cultured mesangial cells of rats using enzyme immunoassay under both basal and thrombin-stimulated conditions. ir-ET-1 was released time-dependently, from isolated glomeruli and cultured mesangial cells. Thrombin (2 U/ml) stimulated the release from both preparations. The release of immunoreactive big endothelin-1 (ir-big ET-1), which was assayed by using enzyme immunoassay, was also time-dependent, and the release was increased by thrombin (2 U/ml; at 4 h, 8 h, and 24 h) in cultured mesangial cells. The releases of big ET-1 and its converted product ET-1 from mesangial cells, an established target for ET-1, suggests that ET-1 acts as an autocrine factor for the cells.

Animals↗
PubMed1991

Cloning, characterization and taxonomic significance of genes for the 5S ribosomal RNA of Leptonema illini strain 3055.

The genes encoding the 5S ribosomal RNA (rRNA) for Leptonema illini strain 3055 were isolated and sequenced. The 5S RNA molecule encoded was 117 nucleotides long. The genome of strain 3055 contained two genes for 5S rRNA that were located close together. The nucleotide sequences of the Leptonema illini genes exhibited less similarity to the rRNA gene of Leptospira interrogans strain Moulton and also to those of typical eubacterial genes than did the rRNA genes of other leptospires. However, the overall secondary structure of the 5S rRNA encoded exhibited a strong similarity to that of typical eubacterial 5S rRNA. Southern hybridization of the 5S rRNA gene probe with the genomic DNA of strain 965, which is currently classified as Leptospira biflexa, showed the latter to have close similarity to that of strain 3055. The physical map of strain 965 was quite similar to that of strain 3055 and was greatly different from that of any other strains of L. biflexa. In the organization of 5S rRNA genes, strain 965 is sufficiently different from other members of the genus Leptospira to be regarded as a member of the genus Leptonema.

Base Sequence↗
PubMed1991

Hyaline globules in Kaposi's sarcoma: a light microscopic and immunohistochemical study.

Hyaline globules (HG) were detected in 51 of 54 Kaposi's sarcoma (KS) lesions (94.4%), including all four non-acquired immunodeficiency syndrome (AIDS) cases of cutaneous KS in this group of cases. Thus, there was no correlation between the presence of HG and the presence or absence of AIDS, nor could we demonstrate any relationship between the presence or prominence of HG and either the histologic pattern or anatomical distribution of KS. HG were located mainly in the cytoplasm of perivascular cells, histiocytoid cells, and spindle-shaped cells and occasionally in endothelial cells lining vessels or slit-like spaces. Extracellular HG were also seen. HG stained positively with periodic acid-Schiff with and without diastase digestion and with phosphotungstic acid-hematoxylin. HG were immunohistochemically negative for alpha 1-antitrypsin, alpha 1-antichymotrypsin, lysozyme, and Factor VIII-related antigen, but the cells containing HG were often positive for alpha 1-antichymotrypsin and occasionally for alpha 1-antitrypsin and Factor VIII-related antigen. HG were also detected in five of six angiosarcomas, two of ten pyogenic granulomas, and seven of 32 inflammatory granulation tissues. These were immunohistochemically similar to HG in KS. Thus, HG are not specific for KS. We support the interpretation that HG are most likely digested erythrocytes.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Endothelin-1 stimulates prostaglandin E2 production in an extracellular calcium-independent manner in cultured rat mesangial cells.

To study a possible role of endothelin-1 (ET-1) in the regulation of glomerular function, we examined the presence of receptors for, and the biological action of, ET-1 in cultured rat mesangial (M) cells. The first-subcultured M cells prepared from isolated glomeruli of Sprague-Dawley rats were used. ET-1 binding was assayed by using 125I-ET-1. Inositol 1,4,5-trisphosphate (IP3) was determined by IP3-specific binding assay. Intracellular calcium (iCa2+) was measured in fura-2 loaded cells. Prostaglandin E2 (PGE2) was measured by radioimmunoassay. In M cells there existed two classes of binding sites specific for ET-1 (Kd was 0.24 and 4.4 nmol/L, Bmax was 130 and 1070 fmol/mg, respectively). ET-1 (10(-7) mol/L) induced a rapid and transient increase in IP3, followed by transient and sustained increases in iCa2+. Nicardipine (10(-6) mol/L) inhibited only the sustained increase in iCa2+. ET-1 (10(-9) mol/L to 10(-7) mol/L) significantly stimulated PGE2 production with the concentration dependency. Nicardipine (10(-6) mol/L) and diltiazem (10(-6) mol/L) did not inhibit the PGE2 production. We conclude that M cells have specific ET-1 receptors linked to phosphoinositide turnover and PGE2 production, and PGE2 production by ET-1 may be through an extra-cellular calcium-independent mechanism. Our results suggest that ET-1 plays an important role in the regulation of glomerular functions by modulating PGE2 production in M cells.

Animals↗
PubMed1991

An approach for immunoradiometric assay with metallic radionuclides: gallium-67-deferoxamine-dialdehyde starch-IgG.

Radiogallium (Ga) labeling of an immunoglobulin-G-deferoxamine conjugate (DF-IgG) to a high-specific radioactivity was performed to allow the development of a radiometallic immunoradiometric assay (IRMA) system. To increase the specific radioactivity of Ga-DF-IgG, we used dialdehyde starch (DAS) as a multi-site spacer for the binding of DF to IgG. Six DF molecules bound to each IgG molecule after DAS conjugation. DF-DAS-IgG was then labeled with the previously reported 67Ga labeling solution, producing labeled IgG with a specific radioactivity of 11,766 MBq/mg IgG. Using this method, we labeled an anti-CA125 tumor-associated antigen monoclonal antibody (130-22), allowing the first application of 67Ga-DF-DAS-IgG to an IRMA system. With this system, a higher sensitivity could be obtained than with 125I IRMA. In addition, a very high correlation (r = 0.995) was obtained between serum CA125 levels as determined by 67Ga IRMA and 125I IRMA. Gallium-67-labeled antibodies with a high-specific radioactivity appear to hold promise for use in highly sensitive radioassay systems.

Antigens, Tumor-Associated, Carbohydrate↗
PubMed1990

Kaposi's sarcoma in patients with acquired immune deficiency syndrome. A flow cytometric DNA analysis of 26 lesions in 21 patients.

The DNA content of formalin-fixed, paraffin-embedded tissue from 21 patients (26 lesions) with Kaposi's sarcoma associated with acquired immune deficiency syndrome (AIDS) was analyzed by flow cytometry. The lesions were classified histologically into the following three types according to the predominant pattern: granulation tissue-like (two lesions), angioma/angiosarcoma-like (ten lesions), and spindle cell (14 lesions). All lesions showed exclusively DNA diploidy, and the S- phase fractions were usually low, ranging from 2% to 13% (mean, 6.9%). The follow-up periods were from 2 to 60 months. Five patients died, with one of the deaths attributed to pulmonary failure resulting from diffuse alveolar damage and Kaposi's sarcoma; the other deaths were attributed to infections. These results indicate that Kaposi's sarcoma is not a high-grade neoplasm and, combined with previously reported evidence, may suggest that Kaposi's sarcoma associated with AIDS is a proliferative process rather than a malignant neoplasm.

Acquired Immunodeficiency Syndrome↗