Search PubMed⌕ Search

Biomedical subjects

C Takahashi

Publications and source records attributed to C Takahashi.

At least 55 records · Page 3Linked to original sources
PubMed1997

[Serum prostate-specific antigen in a urological outpatient clinic. Efficacy of age-specific and prostate volume-specific reference range in detection of prostate cancer].

BACKGROUND: Prostate specific antigen (PSA) is the most available marker for early detection of prostate cancer. Nevertheless, the standard upper range of PSA (4.0 ng/ml) does not demonstrate sufficient specificity. Thus, we evaluated the distribution of PSA by age and prostate volume in urological patients, and determined PSA reference ranges by the each parameter. Diagnostic efficacy was also evaluated. METHODS: Three-hundred-seventy-five patients who visited the urological outpatient clinic between January, 1994 and February, 1996, and were considered not to have prostate cancer, were analyzed PSA levels by age. Among them, two-hundred-seventy-six patients in whom prostate volumes were presumed by means of transabdominal ultrasonography, were evaluated a correlation of PSA values with prostate volumes. Using the age-specific and volume-specific reference ranges determined by this analysis, sensitivity, specificity, and positive predictive value were compared with those in case using the 0.0 to 4.0 ng/ml reference range and the 0.0 to 11.7 ng/ml reference range, in 72 patients (cancer 24, noncancer 48) in whom histological examinations were performed in the same period. RESULTS: We found statistically significant slight correlations among age, prostate volume, and PSA. By using the age-specific reference range, volume-specific reference range, and 0.0 to 11.7 ng/ml reference range, we could elevate the specificity and positive predictive value approximately by 65% and 35%, respectively, compared with those of the 0.0 to 4.0 ng/ml reference range. CONCLUSION: In order to decrease the number of rather invasive than necessary prostate biopsies, age-specific and volume-specific reference ranges are useful in urological outpatient clinic.

Age Factors↗
PubMed1997

The use of genomic in situ hybridization (GISH) to show transmission of recombinant chromosomes by a partially fertile bigeneric hybrid, Gasteria lutzii x Aloe aristata (Aloaceae), to its progeny.

Genomic in situ hybridization (GISH) was used to study somatic chromosomes of parental and progeny plants (all 2n=2x=14) of the bigeneric hybrid between Gasteria lutzii and Aloe aristata (Aloaceae), which is partially fertile, a rare occurrence in plants. GISH successfully distinguished between the two parental genomes in the F1 hybrid and revealed numerous genomic recombinations in chromosomes transmitted by the F1 to the back-cross progeny. The results indicate high levels of meiotic compatibility between the parental genomes, even though they differ in size by 20%. Recombination occurred at a frequency that was higher than that expected from the analysis of orcein-stained meiosis in the F1. The discrepancy suggests that terminalization may occur prior to or during metaphase I, reducing the apparent chiasma frequency, or possibly reveals an under-estimation caused by difficulties in resolving closely grouped chiasmata by eye.

Aloe↗
PubMed1997

Possible involvement of MSX-2 homeoprotein in v-ras-induced transformation.

A truncated MSX-2 homeoprotein was found to induce flat reversion when expressed in v-Ki-ras-transformed NIH3T3 cells. Although the expression of endogenous MSX-2 gene is low in most of the normal adult tissues examined, it is frequently activated in carcinoma-derived cell lines. Likewise, the gene is inactive in untransformed cells but is transcriptionally activated after transformation by v-Ki-ras oncogene, suggesting that the intact MSX-2 may play a positive, rather than suppressive, role in cell transformation. To test this possibility, we isolated a full-length human MSX-2 cDNA and tested its activities in two cell systems: fibroblast and myoblast. In NIH3T3 fibroblasts, although the gene by itself failed to confer a transformed phenotype, antisense MSX-2 cDNA as well as truncated MSX-2 cDNA interfered with the transforming activities of both v-Ki-ras and v-raf oncogene. In C2C12 myoblasts, MSX-2 was found to suppress MyoD gene expression, as do activated ras oncogenes, under certain culture conditions, and truncated MSX-2 cDNA was found to inhibit the activities of both MSX-2 and ras in this system as well. Our findings not only suggest that the truncated version MSX-2 may act as a dominant suppressor of intact MSX-2 but also raise the possibility that MSX-2 gene may be an important downstream target for the Ras signaling pathways.

3T3 Cells↗
PubMed1997

Detection of telomerase activity in prostate cancer by needle biopsy.

OBJECTIVES: Re-expression of telomerase is believed to play an important role in immortalization and carcinogenesis. Thus, telomerase activity is considered to be a potentially useful diagnostic marker. We evaluated the potential diagnostic use of assaying telomerase activity in needle biopsy samples of prostate. METHODS: 114 were obtained from 38 patients with suspected cancer who underwent transrectal ultrasound-guided systematic prostate needle biopsy. Two samples were obtained per site for histological examination and telomerase assay. The activity was assayed using the telomeric repeat amplification protocol and correlated with histological findings. RESULTS: Of the total of 114 samples, 57 were obtained from 22 prostate cancer patients. Telomerase activity was detected in 66% (25/38) of the samples which were histologically confirmed to contain cancerous cells and in 11% (2/19) of the samples from adjacent noncancerous tissues. Of 22 patients with prostate cancer, 82% were positive for telomerase activity in one or more samples by needle biopsy, whereas 1 of 16 patients without histologically cancerous tissues was positive for the telomerase. CONCLUSIONS: The results indicate that telomerase activity in needle biopsy samples is a useful diagnostic marker of prostate cancer.

Adenocarcinoma↗
PubMed1996

Characterization of a human MSX-2 cDNA and its fragment isolated as a transformation suppressor gene against v-Ki-ras oncogene.

A cDNA (termed CT124) encoding a carboxyl-terminal fragment of the human homeobox protein MSX-2 was found to induce flat reversion when expressed in v-Ki-ras-transformed NIH3T3 cells. Although the expression of endogenous MSX-2 gene is low in most of the normal adult tissues examined, it is frequently activated in carcinoma-derived cell lines. Likewise, the gene is inactive in NIH3T3 cells but is transcriptionally activated after transformation by v-Ki-ras oncogene, suggesting that the intact MSX-2 may play a positive, rather than suppressive, role in cell transformation. To test this possibility, we isolated a near full-length human MSX-2 cDNA and tested its activities in two cell systems, i.e. fibroblast and myoblast. In NIH3T3 fibroblasts, although the gene by itself failed to confer a transformed phenotype, antisense MSX-2 cDNA as well as truncated CT124 cDNA interfered with the transforming activities of v-Ki-ras oncogene. In C2C12 myoblasts, MSX-2 was found to suppress MyoD gene expression, as do activated ras oncogenes, under certain culture conditions, and CT124 was found to inhibit the activities of both MSX-2 and ras in this system as well. Our findings not only suggest that CT124 may act as a dominant suppressor of MSX-2 but also raise the possibility that MSX-2 gene may be an important downstream target for the Ras signaling pathways.

3T3 Cells↗
PubMed1995

Involvement of PIM-1 in DNA fragmentation in mouse NS-1-derived cells.

In several cell lines derived from mouse NS-1 myeloma cells, internucleosomal fragmentation of chromosomal DNA, a hallmark of apoptosis, was continuously observed. Approximately 15-20% of the cells died when isolated in a 96-well plate, and the surviving cells contained fragmented DNA ('ladder'). Among a variety of genes so far reported to be related to apoptosis, only Pim-1 was expressed at an elevated level in the NS-1 hybridomas as compared in a control myeloma cell line without 'ladder'. Transfection of a Pim-1 expression vector to a 'ladder'-non-producing myeloma line yielded similar internucleosomal DNA fragmentation. The results hence suggested that Pim-1 activates endonucleases responsible for DNA fragmentation during apoptosis and/or repress DNA repair systems to restore fragmented DNA.

Animals↗
PubMed1995

Cytotoxic metabolites from a fungal adherent of a marine alga.

Leptosins G, G1, G2 and H, belonging to a series of dimeric epipolythiodioxopiperazines, were isolated from the mycelium of a strain of Leptosphaeria sp. stuck on the marine alga Sargassum tortile. Their stereostructures were elucidated by chemical and spectral evidence.

Antineoplastic Agents↗
PubMed1995

Chlordiazepoxide attenuates stress-induced activation of neurons, corticotropin-releasing factor (CRF) gene transcription and CRF biosynthesis in the paraventricular nucleus (PVN).

Corticotropin-releasing factor (CRF) plays a role in coordinating endocrine, autonomic, and behavioral responses to stressful stimuli. Benzodiazepines exert many effects which oppose those of CRF, including anxiolysis and suppression of the pituitary-adrenal axis. In the present study, we employed in situ analysis of CRF heteronucleous RNA (hnRNA) and c-fos mRNA to assess stimulus-induced CRF gene transcription rate following stress and its modulation by chlordiazepoxide (CDP). Male albino rats were exposed to restraint stress for 30 min and sacrificed 30 and 120 min after the onset of stress. Either CDP or vehicle was given intraperitoneally 60 min before stress. To determine plasma ACTH levels by immunoradiometric assay, another group of rats was decapitated 10 min after the onset of restraint stress. Restraint stress induced rapidly and significantly c-fos mRNA and CRF hnRNA expression in the PVN at the 30 min time point. Increases in both RNA copies were significantly inhibited by administration of CDP at doses of 5 and 10 mg/kg. CRF mRNA concentrations were increased significantly in the PVN 120 min after stress and again, CDP attenuated significantly these increases in the PVN. The plasma ACTH increase in response to stress was inhibited significantly by CDP administration at every dose tested. CDP did not change CRF mRNA levels in the non-stressed animal.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Cytokine modulation of interactions between cultured human renal tubular and lymphoid blast cells.

We examined the in vitro cytokine modulation of the interaction of cultured renal tubular epithelial cells (hKEC) with lymphoid effector cells, including mixed lymphocyte reaction (MLR)-derived blasts, Concanavalin A (Con A)-activated blast, and lymphokine-activated killer (LAK) cells. Blast adhesion to hKEC was augmented by treatment with either interferon-gamma (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha), interleukin-1 beta (IL-1 beta), or MLR supernatant. The augmented adhesion statistically correlated with intercellular adhesion molecule-1 (ICAM-1) upregulation on hKEC cells by the cytokines. Blocking of surface ICAM-1 on hKEC or of lymphocyte-function antigen-1 (LFA-1) on the blasts significantly inhibited adhesion. LFA-1 blocking on LAK or MLR blasts resulted in a significant inhibition in cytotoxic function. TNF-alpha and IL-1 beta treatments on hKEC increased the susceptibility to LAK cytotoxicity, whereas IFN-gamma and MLR supernatant treatment significantly reduced this susceptibility. Absorption of IFN-gamma from the MLR supernatant partially restored the susceptibility of LAK cytotoxicity. The combined data suggest the importance of cytokine regulation of LFA-1/ICAM-1 adhesion molecule in these cellular interactions. Although IFN-gamma augments attachment between hKEC and blastic effector cells, this cytokine endows hKEC with resistance to LAK cytotoxicity. Thus, it is clear that cytokine modulation is a complicated phenomenon involving both adhesion molecule regulation-dependent and independent mechanisms.

Absorption↗
PubMed1995

Possible anti-tumour-promoting activity of components in Japanese soybean fermented food, Natto: effect on gap junctional intercellular communication.

In order to detect any protective agent against tumor formation, we examined the anti-tumor-promoting effect of a Japanese traditional soybean fermented food, Natto. Dye transfer was employed as an assay method. When fluorescent dye was microinjected into cultured BALB/3T3 cells, the dye was transformed into the neighboring cells through the gap junction. This dye transfer was blocked by the treatment with the tumor promoters 12-O-tetra-decanoylphorbol-13-acetate (TPA), a high concentration of NaCl and lithocholic acid (LCA). This reduction of the dye transfer by TPA treatment was not observed when the cells were pretreated with retinoic acid, an anti-tumor promoter. Thus, the recovery of the dye transfer in TPA-treated BALB/3T3 cells was proven to ge a good indicator for detecting some possible anti-tumor promoters. After extraction and fractionation of Natto, we obtained an active fraction (H1) which showed recovery of the dye transfer in TPA-treated cells. The fraction contained straight-chain saturated hydrocarbons. A comparison of the fraction and the authentic samples by GC analysis suggests that the H1 fraction contained straight-chain saturated hydrocarbons from around C30 to C32. Among these hydrocarbons, hentriacontane (C31) was found at the highest concentrations, and was shown to have the highest activity. Hentriacontane at a very low concentration of 0.65 ng/ml was shown to recover the dye transfer inhibited by the treatment with TPA as well as with NaCl and LCA.

3T3 Cells↗
PubMed1995

Accumulation of phosphatydilcholine-hydroperoxide in dialysis patients with diabetic nephropathy.

Plasma lipid peroxidation in noninsulin dependent diabetes mellitus (DM) patients were evaluated in DM patients undergoing hemodialysis (HD) by means of a chemiluminescence-HPLC for the specific determination of phosphatidylcholine hydroperoxide (PCOOH). Thirty-three uremic patients with DM nephropathy, undergoing 12 hours HD a week using polymethylmethacrylate membrane, were studied. Of them 22 DM patients on HD were divided into 2 age and sex matched groups treated and conventional group in order to clarify therapeutic effect of 500 mg alfa-tocopherol and 600 mg probucol daily. Fifty DM patients without end-stage renal disease (ESRD) who were age-, period of diabetes-, and sex-matched, were selected as positive control of the subjects. Plasma PCOOH levels were significantly elevated in both DM patients, while the plasma PCOOH in normal controls were 227.0 +/- 68.7 pmol/ml. Plasma PCOOH levels of DM patients undergoing HD were significantly higher than that of patients without ESRD (1,330.8 +/- 642.7 pmol/ml vs. 756.6 +/- 431.9 pmol/ml, p < 0.025). Partial correlation coefficient of plasma PCOOH level demonstrated PCOOH and period of HD in DM patients were highly significantly positively correlated (p < 0.01), although single session of HD was not found to produce significantly increased lipid-peroxidation. Plasma PCOOH roughly remained within similar levels as base lines by medication with anti-oxidant compared to that of conventional group. From these results we conclude that HD intensifies lipid peroxidation and such accumulation of hydroperoxide could account for accelerated progress of atherosclerosis in DM patients with renal insufficiency. It is worthwhile to try an administration of free radical scavenger in order to reduce PCOOH and slow down the progression of atherosclerotic vascular disease.

Adult↗
PubMed1994

Transforming growth factor beta 1 is an inducer of erythroid differentiation.

Normal human bone marrow cells, highly enriched for burst-forming units-erythroid (BFU-E), were cultured in serum-free medium, in the presence and absence of various factors, to investigate the mechanisms involved in regulating erythroid differentiation. In cultures containing interleukin 3 (IL-3), Steel factor (SF), and erythropoietin (Ep), benzidine-positive erythroblasts first became detectable on day 6. Their numbers then rapidly increased until, by day 16, > 99% of the cells, which were 20,000-fold amplified over input numbers, were benzidine-positive. It is interesting to note that omission of either SF or Ep from this assay markedly enhanced the rate of differentiation and reduced total cell numbers, whereas omission of IL-3 had no effect on the rate of differentiation and only slightly reduced cell numbers. Of various agents tested, the most potent erythroid differentiation inducer (and inhibitor of cell proliferation) was found to be transforming growth factor beta 1 (TGF-beta 1). This cytokine stimulated both the rapid appearance of hemoglobin-positive cells and an early cessation of cell proliferation. Using fluorescently tagged antibodies to glycophorin A and fluorescence-activated cell sorter (FACS) analysis, this phenomenon was shown to be due to an early induction of erythroid differentiation rather than an aberrant production of hemoglobin. Methylcellulose assays indicated that the well-documented reduction of BFU-E colony numbers observed with TGF-beta 1 may actually be due to a TGF-beta 1-induced "conversion" of BFU-E into colony-forming units-erythroid (CFU-E). Thus, in vivo, TGF-beta 1 might serve, in part, to decrease the number of mature erythrocytes by stimulating BFU-E to skip a number of cell divisions and differentiate early.

Animals↗
PubMed1994

Calcium regulating hormones and bone mineral content in patients after subtotal gastrectomy.

Twenty-nine men who had undergone Billroth I gastrectomy and 19 men who had undergone Billroth II gastrectomy were studied to examine the changes in their calcium regulating hormones and bone mineral content following surgery. The serum calcium and phosphate concentrations in the patients with Billroth I and Billroth II were normal. The Billroth II group had an elevated level of serum alkaline phosphatase and reduced bone mineral content. The 24,25(OH)2D concentration was reduced (P < 0.01) and 25(OH)D and 1,25(OH)2D concentrations were increased (P < 0.01, P < 0.05, respectively) in the Billroth II group. It was suggested by our study that the Billroth II patients had a reduced bone mineral content and an elevated 1,25(OH)2D concentration. Therefore, the pathophysiology of postgastrectomy bone metabolic disease is not due to vitamin D deficiency, but may instead be due to reduced calcium absorption in the intestine.

Aged↗
PubMed1994

Leptosins I and J, cytotoxic substances produced by a Leptosphaeria sp. Physico-chemical properties and structures.

Leptosins I and J, belonging to a series of epipolythiodioxopiperazines, have been isolated from the mycelium of a strain of Leptosphaeria sp. OUPS-4 attached to the marine alga Sargasssum tortile. Their relative stereostructures have been elucidated by chemical and spectral evidence. These compounds exhibited significant cytotoxic activity against cultured P388 cells.

Antibiotics, Antineoplastic↗
PubMed1993

Importance of E-selectin (ELAM-1) and sialyl Lewis(a) in the adhesion of pancreatic carcinoma cells to activated endothelium.

Adhesion molecules involved in attachment between human pancreatic carcinoma and activated endothelial cells in vitro were investigated. Basal adhesion occurred between 6 pancreatic carcinoma cell lines and unstimulated human umbilical vein endothelial cells (HUVEC), and augmented basal adhesion to activated HUVEC was only seen when pancreatic cancer cells expressed sialyl Lewisa (SLea) and sialyl Lewisx (SLex). Activation of HUVEC with interleukin 1-beta (IL-1 beta) or tumor necrosis factor-alpha (TNF-alpha), but not with interferon-gamma (IFN-gamma), generated the augmentative basal adhesion. Dose dependence and additive effect were observed in augmentation of the basal adhesion induced by IL-1 beta and/or TNF-alpha. Increase in adhesion correlated with up-regulation of the surface E-selectin (or ELAM-1) on HUVEC, and was evident at both 25 degrees C and 4 degrees C. Anti-E-selectin and anti-SLea blocked the augmented attachment, whereas anti-SLex, an antibody against another known ligand for E-selectin, did not. The collective evidence indicates that attachment between pancreas carcinoma cells and activated endothelial cells is regulated by cytokines such as IL-1 beta and TNF-alpha, and is mediated by SLea on pancreas carcinoma and E-selectin on endothelial cells. These molecules may be of significant importance in blood-borne metastasis of pancreatic carcinoma cells to inflamed sites.

Aged↗
PubMed1993

Enzyme immunoassay and characterization of pancreatic stone proteins in human urine.

An enzyme immunoassay of pancreatic stone protein (PSP) in human urine was developed. Mean analytical recovery of pure PSP-S2-5 added to urine was 102.3% (SD 5.9%), and the precision of the assay was 2.0-2.7% within an assay and 2.5-2.9% between assays. In healthy volunteers (age 20-55 years), the mean value of the PSP concentration, expressed as ratios to urine creatinine, was 129 +/- 88 (mean +/- SD) micrograms/g without any differences for sex. Urine PSP correlated with urine N-acetylglucosaminidase (NAG) (r = 0.354). The molecular forms of immunoreactive PSP in urine were characterized by using cation exchange chromatography (Mono S), SDS-PAGE, N-terminal sequence, and enzyme immunoassay analysis. The urine PSP, eluted at the position corresponding to PSP-S2-5 on cation exchange chromatography, was converted to PSP-S1 by trypsin digestion. The difference in mobility on SDS-PAGE between urine PSP and PSP-S2-5 seems to be due to a glycosylated undecapeptide (N-terminal 1-11). The proposed method offers a sensitive, specific, and reproducible tool for laboratory analysis of human urine PSP levels.

Acetylglucosaminidase↗