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Biomedical subjects

T Terasaki

Publications and source records attributed to T Terasaki.

At least 163 records · Page 9Linked to original sources
PubMed1988

Levels of glutathione S transferase pi mRNA in human lung cancer cell lines correlate with the resistance to cisplatin and carboplatin.

The amounts of mRNA for glutathione S transferase pi (GST pi) were significantly lower in 3 human small cell lung cancer (SCLC) cell lines than in 3 non small cell lung cancer (NSCLC) cell lines. The sensitivities of the 3 SCLC cell lines to cisplatin and carboplatin were much higher than those of the 3 NSCLC cell lines. These results indicate that low levels of GST pi mRNA expression in SCLC cell lines inversely correlate to high sensitivity to cisplatin and carboplatin, and further suggest that GST pi may play an important role in intracellular inactivation of these drugs.

Carboplatin↗
PubMed1988

Differential binding of testosterone and estradiol to isoforms of sex hormone-binding globulin: selective alteration of estradiol binding in cirrhosis.

The MCR of testosterone is decreased but the MCR of estradiol is unchanged in men with cirrhosis and elevated serum sex hormone-binding globulin (SHBG) concentrations. Previous studies indicated that SHBG from cirrhotic men selectively delivers estradiol, but not testosterone, to peripheral tissues of rats in vivo. These results suggest that estradiol and testosterone may bind to different SHBG isoforms in serum and that the estradiol-binding isoforms may be selectively altered in cirrhosis. This hypothesis was tested by polyacrylamide gel isoelectric focusing and fast protein liquid chromatography chromatofocusing. After Concanavalin-A affinity purification of serum glycoproteins from pregnant women, normal men, normal women, and cirrhotic men, the glycoprotein fraction was reconstituted, labeled with [3H]testosterone or [3H]estradiol, and applied to isoelectric focusing gels. Testosterone was bound selectively by the most acidic isoforms of SHBG, pI 4.5-5.4, and there was a significant anodal shift of the estradiol-binding isoforms in serum from cirrhotic men compared to that in serum from normal men. The selective binding of testosterone to the most acidic isoforms of SHBG was confirmed by fast protein liquid chromatography chromatofocusing, wherein the binding reactions were measured at neutral pH after separation of the isoforms. These biochemical studies and previous physiological experiments question the conventional view that testosterone and estradiol bind to a single competitive binding site on SHBG. Rather, testosterone is selectively bound by the most acidic SHBG isoforms. The estradiol-binding isoforms undergo a significant anodal shift in cirrhosis; this abnormality may result in the lack of decrease in estradiol MCR in cirrhosis.

Adult↗
PubMed1988

Electron microscopical observation of RNA on the surface of Ehrlich ascites tumor cells.

The structure of RNA on the surface of Ehrlich ascites tumor cells was studied under an electron microscope using both plasma polymerization replica films and ultrathin sections of the cells. Necklace-like structures were found on the cell surface where anti-RNA antibody was bound in replica film, and particles which resemble cytoplasmic ribosomes in size and density were found distributed sparsely on the cell surface in ultrathin sections. These particles were found to gather at one pole of the cell surface after the cell was incubated at 4 degrees C with anti-RNA antibody and then incubated at 37 degrees C for 10 min in antibody-free medium. On the other hand, L1210 cells which do not bind with anti-RNA antibody showed hardly any such structures on the cell surface. These results suggest that RNA on the surface of Ehrlich ascites tumor cells is present in the form of particles.

Animals↗
PubMed1988

Clonal isolation and characterization of myoblast-like reconstituted cells formed by fusion of karyoplasts from mouse teratocarcinoma cells with rat myoblast cytoplasts.

To examine the roles of the cytoplasms of differentiated somatic cells on nuclear gene expression, reconstituted cells (RC-cells) were isolated clonally by fusing karyoplasts (isolated nuclei) from neomycin-resistant mouse teratocarcinoma PCC4-neor cells with cytoplasts (isolated cytoplasms) of chloramphenicol (CAP)-resistant rat myoblasts L6TG.CAPr cells, and after double selection in the medium containing 400 micrograms/ml of neomycin and 100 micrograms/ml of CAP (G418 plus CAP medium). The RC-cells were characterized by the presence of two genetic markers, neomycin- and CAP-resistance, by the absence of latex beads which had incorporated into karyoplast donor PCC4-neor cells as a cytoplasmic physical marker, and by the similar karyotypes as that of parental PCC4-neor cells. In contrast to the teratocarcinoma cybrids previously isolated, all the isolated RC-clones expressed myoblast-like morphologies of three types. The phenotypic expression of these RC-cells was compared with that of PCD-1 cells, a teratocarcinoma-derived myoblast line. RC-cells and PCD-1 cells did not express alkaline phosphatase (ALPase) activity while parental PCC4-neor expressed it strongly. After induction of myogenic differentiation by treatments with excess thymidine and conditioned medium, two clones were capable of forming short multinucleated cells. The protein synthetic patterns of RC-cells analysed by two-dimensional polyacrylamide gel were different from PCC4-neor cells, and quite resembled those of PCD-1 cells. Particularly, multinucleated RC-clones expressed alpha-tropomyosin, and contained 10 nm filaments, characteristic markers of early myogenic cells. These results suggest that the RC-cells are myoblast-like cells, that a few of them maturate to partially differentiated myogenic cells, that the rat myoblast cytoplasm contains regulatory factor(s) able to determine the myogenic cell lineage of the undifferentiated stem cells, and that this factor is continuously expressed in these myoblasts.

Alkaline Phosphatase↗
PubMed1988

Heterogeneity of lung cancer cells with respect to the amplification and rearrangement of myc family oncogenes.

Seventy lung tumors from 53 patients were analysed for alterations of myc family oncogenes, c-myc, N-myc and L-myc, to evaluate when activation of these genes occurs during tumor development. The 53 cases were 17 small cell carcinomas (SCCs), 18 adenocarcinomas, 12 squamous cell carcinomas (SqCs), 4 large cell carcinomas and 2 adenosquamous carcinomas. Either N-myc or L-myc was amplified in 4 of the 17 (one N-myc and 3 L-myc) SCCs (24%), while c-myc was amplified in 3 of the 12 SqCs (25%). In one SCC, amplification of N-myc was found in the primary tumor, a pulmonary hilar lymph node metastasis and a pleural metastasis, but not in a liver metastasis or a para-aortic lymph node metastasis. In one SqC, c-myc was amplified in a pleural metastasis and a lymph node metastasis, but not in the primary tumor. In 2 cases of SCCs, amplification or rearrangement of c-myc was detected only in the cell lines, but not in the original tumors taken from the same individuals. These results indicate that tumor cells were heterogeneous for amplification and rearrangement of myc family oncogenes, and suggest that activation of these oncogenes in SCCs and SqCs occurs not at the time of malignant transformation but during tumor progression.

Chromosome Mapping↗
PubMed1988

Altered expression of the retinoblastoma (RB) gene in small-cell carcinoma of the lung.

Nine lung small-cell carcinoma (SCC) cell lines and 9 lung non-SCC cell lines were examined for structural changes of the retinoblastoma (RB) gene as well as its expression using a complementary DNA probe. The RB protein product was investigated using an anti-RB antibody which we produced. Although homozygosity or hemizygosity of the RB gene was suggested in 8 of 9 SCCs and one of 2 large cell carcinomas (LCCs) by Southern blot analysis using an RB cDNA probe and polymorphic DNA markers for chromosome 13, no obvious structural changes of the RB gene were detected in these 18 cell lines. However, RB transcripts were either markedly reduced in quantity or abnormal in length in 3 of 9 SCCs. The specific 115 kD protein was not immunoprecipitated by the anti-RB antibody in all 9 SCCs with either normal or abnormal size RB mRNA. Three of 4 adenocarcinomas (AdCs), all 3 squamous cell carcinomas, and one of 2 LCCs expressed normal size RB mRNA, and the 115 kD protein was immunoprecipitated by the anti-RB antibody. The 115 kD protein was also absent in one of 2 LCCs with shortened RB mRNA and in one of 4 AdCs with low level of RB mRNA expression. These results strongly suggest that inactivation of the RB gene might be involved in the development of lung cancers, especially of SCCs.

Adenocarcinoma↗
PubMed1988

[Ofloxacin for the treatment of chlamydial urethritis].

The effect of Ofloxacin administered orally 600 mg everyday for 14 days was evaluated in 20 male patients with Chlamydial urethritis, in whom Chlamydia was identified from urethral secretion by immunohistochemical technique using monoclonal primary antibody specific for all known serotypes of Chlamydia trachomatis and psittaci. 19 out of the 20 patients showed an improvement of subjective and/or objective symptoms after the treatment. The Chlamydia reaction turned to negative in 13 patients and to (+/-) in another patient. The overall clinical effect was excellent in 7, good in 6 and poor in 7, showing a effective rate of 65%. No side effects were observed.

Adult↗
PubMed1987

Reversible squamous cell characteristics induced by vitamin A deficiency in a small cell lung cancer cell line.

A cultured small cell lung cancer cell line (Lu-134-B-S) established from a xenotransplanted tumor in a nude mouse, which had originated from a primary focus of small cell lung cancer, showed morphological changes when the medium was changed from RPMI 1640 supplemented with 10% fetal calf serum to RPMI 1640 supplemented with 10% delipidized fetal calf serum. That is, it consisted of "classic" small cells in the former medium, but after eight passages in the latter medium many cells became squamous cells, possessing abundant eosinophilic cytoplasm and intercellular bridges. Immunohistochemically, they reacted to antikeratin and antiinvolucrin antibodies. Electron microscopically, well developed desmosomes and associated tonofibrils were noted, and electrophoretically, the amount of medium (Mr 57,000 and 59,000) and large-sized (Mr 67,000) keratins were found to increase with the change of the medium. These changes reversed to the original small cell morphology within 4 weeks after addition of vitamin A (retinoic acid) to the medium. These findings suggested that deficiency of vitamin A caused the change of the cell from small to squamous cell and vice versa.

Aromatic-L-Amino-Acid Decarboxylases↗
PubMed1987

Saturable uptake of cefixime, a new oral cephalosporin without an alpha-amino group, by the rat intestine.

The mechanism of intestinal uptake of cefixime, a new oral cephalosporin antibiotic, has been examined using the everted jejunum of rats. The initial uptake rates were apparently pH-dependent with the maximum rate at pH 5.0 and a 3-fold reduction at pH 7.0. The uptake at pH 5.0 followed mixed-type kinetics involving saturable and non-saturable processes in a manner similar to that for several amino-beta-lactam antibiotics. Cefixime uptake was inhibited significantly by 20 mM permeants such as cyclacillin, cephradine, benzylpenicillin, propicillin, glycyl-L-proline and glycyl-glycine. Replacement of Na+ in the medium with choline produced a slight but significant inhibition of cefixime uptake. In spite of the absence of significant inhibition by the amino acids glycine and proline, the dipeptide, glycyl-L-proline in Na+-free medium showed a marked inhibitory effect. The inhibition kinetics of cefixime uptake by glycyl-L-proline and cyclacillin were consistent with competitive-type inhibition. This study provides the first evidence of saturable intestinal uptake of a cephem antibiotic without an alpha-amino group in the side chain, suggesting transport through the dipeptide carrier system(s).

Animals↗
PubMed1987

Stereospecificity of triiodothyronine transport into brain, liver, and salivary gland: role of carrier- and plasma protein-mediated transport.

The stereospecificity of T3 transport through the walls of the brain capillary, i.e. the blood-brain barrier (BBB), and the salivary gland capillary and through the hepatocyte plasma membrane was studied with a tissue-sampling single injection technique in rats. In the absence of plasma proteins, the ED50 of inhibition of the saturable transport of [125I]L-T3 through the BBB was 1 microM for unlabeled L-T3 and 9 microM for unlabeled D-T3. The brain extraction of [125I]D-T3, 5.9 +/- 0.1% (+/- SE), was about one third that of [125I]L-T3. Conversely, no saturable and no stereospecific T3 transport was observed for the salivary gland capillary, which, unlike the brain capillary, is porous. The hepatic extraction of T3 was minimally stereospecific in the absence of plasma proteins. In the presence of 5 g/dl bovine albumin, the fraction of circulating D- or L-T3 that was available for transport into liver (50-100%) was many-fold greater than the fraction that was free in vitro (approximately 2%); therefore, both D-T3 and L-T3 were available for uptake by liver from the circulating albumin-bound pool. This plasma protein-mediated transport of T3 is believed to represent a process of enhanced dissociation of T3 from the albumin-binding site, since the plasma protein per se is not significantly taken up by liver on a single pass. However, in the presence of 5 g/dl bovine albumin, the extravascular hepatic extraction of [125I]D-T3 (50 +/- 2%) was nearly half that for [125I]T3 (93 +/- 12%), although no significant difference in the in vitro binding of [125I]D-T3 and [125I]L-T3 to 5 g/dl bovine albumin was found with equilibrium dialysis. In addition, the isoelectric point of bovine albumin bound to [125I] L-T3 (5.1) was higher than that of bovine albumin bound to [125I] D-T3 (5.0), as determined by isoelectric focusing, which indicates that the surface of the bovine albumin molecule is slightly more positive when the protein binds L-T3 as opposed to D-T3. The isoelectric focusing and in vivo transport data together suggest that the interaction between the surfaces of the plasma protein and the hepatic microcirculation that is presumed to cause enhanced hormone dissociation from the protein-binding site is electrostatic in nature. These studies (1) show that the BBB thyroid hormone transport system is sharply stereospecific, and this property is probably a major factor underlying the low biological potency of D-T3 in brain.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1987

A continuous sampling model of the seminal vesicle fluid in rat.

A continuous sampling model of the fluid excreted from the unilateral seminal vesicle was devised in the rat. Each 12 hr change in the volume was measured in 14 sexually mature male rats by use of tubing. If we assume the excretion of a small volume (less than 4 microliters) as the resting level, 3 of 14 rats showed only the resting level. The excretion of a large volume was sometimes observed in the 11 other rats both in daytime and nighttime. This model would be promising for investigations of the seminal vesicles from new aspects.

Animals↗
PubMed1987

H+ gradient-dependent and carrier-mediated transport of cefixime, a new cephalosporin antibiotic, across brush-border membrane vesicles from rat small intestine.

The characteristics of the transport of cefixime, a new p.o. cephalosporin, antibiotic, were studied by using brush-border membrane vesicles from the rat small intestine. The initial rate of uptake of cefixime was not affected by the presence of an inward gradient of either Na+ or other monovalent cations. With an intravesicular pHi of 7.5, optimal cefixime uptake occurred at an extravesicular pHo of 5.0, with about 6-fold acceleration compared with that in the absence of an inward proton gradient (pHi = pHo = 7.5). A protonophore, carbonyl-cyanide-4-trifluoromethoxy-phenylhydrazone, abolished the stimulating effect of low pHo. In the presence of a sufficient inward proton gradient (pHi = 7.5, pHo = 5.0), cefixime uptake showed an overshoot phenomenon and apparent saturation kinetics expressed by the Michaelis-Menten equation with the maximum rate of 2.67 +/- 0.06 nmol/30 sec/mg of protein and a Michaelis constant of 0.83 +/- 0.04 mM. Cefixime uptake was inhibited competitively by glycyl-L-proline and stimulated by the countertransport effect of this dipeptide. The other peptides also inhibited cefixime uptake significantly. A valinomycin-induced inside-negative K+-diffusion potential had a dramatic reducing effect on the uptake of dianionic cefixime. All the data obtained in this study demonstrate that cefixime transport across the brush-border membrane vesicles is carrier-mediated, independent of Na+ and dependent on a H+ gradient via the peptide transport systems.

Amino Acids↗
PubMed1986

Uptake of benzylpenicillin, cefpiramide and cefazolin by freshly prepared rat hepatocytes. Evidence for a carrier-mediated transport system.

The kinetics and mechanism of the hepatic uptake of beta-lactam antibiotics were studied by using freshly prepared rat hepatocytes. The initial uptake rates of benzylpenicillin and cefpiramide represented both saturable and nonsaturable transport processes, whereas that of cefazolin showed an apparently nonsaturable uptake process within the concentration range below 4 mM. The apparent nonsaturable uptake rate constants for benzylpenicillin, cefpiramide and cefazolin were 0.580, 0.047 and 0.289 nmoles/min/mg protein/mM respectively. The apparent values of Kt and Vmax describing the saturable transport were 0.473 +/- 0.158 mM and 2.02 +/- 0.48 nmoles/min/mg protein for benzylpenicillin and 0.847 +/- 0.254 mM and 0.70 +/- 0.18 nmoles/min/mg protein for cefpiramide respectively. The Arrhenius plot of benzylpenicillin uptake of 200 microM presented a single straight line in the range of 22 degrees-37 degrees with an activation energy of 16.8 kcal/mole. An energy requirement was also demonstrated for benzylpenicillin uptake as metabolic inhibitors (antimycin A, NaCN, rotenone and 2,4-dinitrophenol) significantly reduced the initial uptake rate of benzylpenicillin (P less than 0.05). Uptake of benzylpenicillin (200 microM) was not inhibited by ouabain (1 mM). Benzylpenicillin uptake was inhibited competitively by phenoxymethylpenicillin, cefpiramide and cefazolin with the inhibition constants, Ki, of 0.680, 0.583 and 11.7 mM respectively. Benzylpenicillin also inhibited competitively the uptake of cefpiramide with a Ki of 0.655 mM. From these results it was considered that a carrier-mediated uptake system participates in the hepatic uptake of at least four of the beta-lactam antibiotics examined in this study.

Animals↗