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Biomedical subjects

A Shinohara

Publications and source records attributed to A Shinohara.

138 records · Page 8Linked to original sources
PubMed1984

Rathke cleft cysts.

Three cases of Rathke cleft cyst are presented. The clinical symptoms were disturbances of visual acuity and visual fields, and a functional disorder of the hypophysis. In two cases, there were associated meningeal signs. This meningitis was considered to be aseptic and ascribable to leakage of the cyst contents into the subarachnoid space. In one patient, the cyst extended to the suprasellar cistern; a computed tomography scan revealed an enhanced capsule, high-density spotting in a low-density area inside the cyst, and enhanced areas. In another patient, the tumor was localized in the sella turcica; high-density spotting was seen. Based on this finding, we suggest that computed tomography scanning facilitates differentiation from other sellar lesions to some degree. Electron microscopic studies of a cyst with cilia revealed the presence of a coating material around cells with microvilli. On the basis of this finding, Rathke cleft cysts may be considered to be namely, endodermal, inclusions from the upper respiratory tract.

Adult↗
PubMed1984

Species differences in the N-acetylation by liver cytosol of mutagenic heterocyclic aromatic amines in protein pyrolysates.

The N-acetylation of 3-amino-1-methyl-5H-pyrido[4,3-b]-indole (Trp-P-2) and other heterocyclic aromatic amine promutagens isolated originally from protein pyrolysates was investigated using liver cytosols from various animal species and acetyl-CoA as an acetyl donor. Marked species differences in the enzymatic N-acetylation activity of these heterocyclic amines were observed. The N-acetylation activity also varied among the substrates used. The N-acetylation of these heterocyclic amines by hepatic cytosols from all animal species used was much less than that of the non-heterocyclic aromatic amine carcinogen, 2-aminofluorene (2-AF): the N-acetylation of Trp-P-2 was more than one hundred times less than that of 2-AF. These results suggested that the metabolic activation pathway of these mutagenic heterocyclic amines is different from that of 2-AF. The hamster but not rat cytosol showed the ability to utilize N-hydroxy-2-acetylaminofluorene and 2-acetylaminofluorene as acetyl donor in the N-acetylation of Trp-P-2.

Acetylation↗
PubMedDate not supplied

Determination of terbium in organs of mice administered terbium chloride: comparative study of fluorometry and atomic absorption spectrometry.

The determination of terbium (Tb) in organs by fluorometry and atomic absorption spectrometry (AAS) was investigated. The organs of mice were ashed before the instrumental applications. The fluorometric measurement of Tb was performed after formation of a complex with dipicolinate. The detection limit was 0.1 micrograms/mL and the coefficient of variation was less than 5% (N = 6). AAS measurement of Tb was carried out with a pyrolytic graphite furnace. The detection limit by AAS was 1 microgram/mL. The concentrations of Tb in various organs of mice intraperitoneally administered TbCl3 at doses of 10, 50, and 250 mg Tb/kg were measured by both methods. The values obtained from each organ were dependent on the dose. High concentrations of Tb were found in spleen, pancreas, and seminal vesicle; lesser amounts were found in liver and testis. The correlation coefficient for both methods was high; r = 0.991 (N = 20) in liver and r = 0.988 (N = 20) in pancreas.

Animals↗
PubMedDate not supplied

Determination of germanium in human specimens: comparative study of atomic absorption spectrometry and microwave-induced plasma mass spectrometry.

The determination methods of germanium (Ge) in biological specimens such as blood plasma, erythrocytes, urine, hair, nail, and other organs were established using graphite furnace atomic absorption spectrometry (GFAAS) and microwave-induced plasma mass spectrometry (MIP-MS). The detection limits of Ge standard solution were 3 ng/mL with GFAAS and 0.05 ng/mL with MIP-MS. The detection limits in organ samples depended on the type of samples and sampling amounts: 3-30 ng/g by GFAAS and 0.05-0.5 ng/g by MIP-MS. The sensitivity of GFAAS was lower than that of MIP-MS; however, it was adequate for determining Ge concentrations in specimens from patients who had ingested Ge. Samples were digested by a simple wet-ashing procedure using nitric acid and perchloric acid. To avoid the interfering effects of coexisting elements and perchloric acid residue, an extraction method using organic solvent was tried. When using MIP-MS, extraction was not necessary; however, both dilution and addition of an internal standard were needed. Special attention was required for iron-rich samples because a molecular ion of 56Fe16O was observed at nm/z72 where 2Ge was monitored. The results of Ge concentrations in human samples obtained by these methods agreed well. Interfering effects of perchloric acid, which was used for digestion and which remained in samples, were observed in both methods. Hair and nail samples from people who had ingested Ge were useful for monitoring Ge in the body. Hair samples were useful for determining past exposure to Ge when the distribution patterns from the scalp to the end of the strand were analyzed. In control subjects, Ge concentrations in the listed specimens and organs were lower than 0.1 microg/g or mL, and these low levels of Ge were able to be determined by MIP-MS in combination with the extraction method.

Aged↗
PubMedDate not supplied

Lack of c-mpl proto-oncogene transcripts and growth-stimulatory effects of thrombopoietin on human small cell lung cancer cell lines.

Thrombopoietin (TPO) is a recently discovered hematopoietic growth factor which stimulates the production and maturation of megakaryocytes. In this study, we used a modified MTT assay to examine the in vitro growth-stimulatory effects of recombinant human (rh) TPO and recombinant human stem cell factor (rhSCF) on eight small cell lung cancer (SCLC) cell lines and one leukemic cell line, CMK, with megakaryocytic characteristics. rhTPO did not reveal any stimulatory effects on all eight SCLC cell lines, while rhSCF demonstrated a modest growth-stimulatory effect on one etoposide-resistant SCLC cell line (H69/VP). The transcripts of c-mpl, the receptor of TPO, was not detected in all SCLC cell lines by RT-PCR analysis, while those of c-kit, the receptor of SCF, were detected in five of eight SCLC cell lines. Our data suggest that rhTPO does not promote the growth of SCLC cell lines and may be clinically applicable for patients with this disease. Moreover, rhSCF may cause adverse effects in part of the SCLC patients.

Base Sequence↗
PubMedDate not supplied

Synergistic effects of danazol and mifepristone on the cytotoxicity of UCN-01 in hormone-responsive breast cancer cells.

BACKGROUND: 7-Hydroxystaurosporine (UCN-01) is a novel antitumor agent as well as a potent inhibitor of a variety of protein kinases with a preference to protein kinase C. Because an intimate interaction exists between PKC signaling and the ER signaling pathways, sex steroid agonists/antagonists might modulate the cytotoxicity of UCN-01. MATERIALS AND METHODS: Effects of sex steroid agonists and antagonists on the UCN-01 cytotoxicity were analyzed by MTT assay in MCF-7/WT and MCF-7/ADR, a multiple drug resistance phenotype lacking ER and PR. RESULTS: MCF-7/ADR is 23-fold more resistant to UCN-01 than MCF-7. In MCF-7/WT, danazol and mifepristone enhanced the cytotoxicity of UCN-01, while these agents did not exert any significant effects on it in MCF-7/ADR. CONCLUSION: These results suggest that danazol or mifepristone might enhance the antitumor activity of UCN-01 in hormone-dependent cancer cells by interacting with PR.

Alkaloids↗