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T Seguchi

Publications and source records attributed to T Seguchi.

At least 37 records · Page 2Linked to original sources
PubMed1993

Flow cytometric analysis of nuclear DNA content of renal cell carcinoma correlated with histologic and clinical features.

BACKGROUND: The prognostic value of flow cytometric analysis of DNA content is contradictory in renal cell carcinoma (RCC). METHODS: Flow cytometric analysis was performed on 72 patients with RCC, and the relationship between the DNA content and pathologic or clinical features was investigated. RESULTS: Aneuploidy was observed in 36 (50%) of these patients. Two tissue samples from primary tumors of 12 patients were analyzed, and heterogeneity was found in 7 (58%) of these patients. The incidence of aneuploidy was significantly higher in high-grade than in low-grade tumors (P = 0.0328). All five tumors with a maximum diameter of 2.5 cm or smaller (T1N0M0) were diploid, and a trend for more aneuploid tumors among high-stage diseases was observed. The survival rate of patients with diploid tumors was not significantly different from that of those with aneuploid tumors in the low- or high-stage group. CONCLUSIONS: DNA ploidy assessed with one sample is not a prognostic factor, and heterogeneity between different samples of a given tumor indicates that one sample is not enough for DNA flow cytometry in RCC.

Adult↗
PubMed1993

The mechanism for the activation of latent TGF-beta during co-culture of endothelial cells and smooth muscle cells: cell-type specific targeting of latent TGF-beta to smooth muscle cells.

Transforming growth factor-beta (TGF-beta) is secreted in a latent form and activated during co-culture of endothelial cells and smooth muscle cells. Plasmin located on the surface of endothelial cells is required for the activation of latent TGF-beta (LTGF-beta) during co-culture, and the targeting of LTGF-beta to the cellular surface is requisite for its activation. In the present study, the cellular targeting of LTGF-beta was examined. We detected the specific binding of 125I-large LTGF-beta 1 isolated from human platelets to smooth muscle cells but not to endothelial cells. A mAb against the latency-associated peptide (LAP) of large LTGF-beta 1 complex, which blocked the binding of 125I-large LTGF-beta 1 to smooth muscle cells, inhibited the activation of LTGF-beta during co-culture. The binding of 125I-large LTGF-beta 1 could not be competed either by mannose-6-phosphate (300 microM) or by the synthetic peptide Arg-Gly-Asp-Ser (300 micrograms/ml). These results indicate that the targeting of LTGF-beta to smooth muscle cells is required for the activation of LTGF-beta during co-culture of endothelial cells and smooth muscle cells. The targeting of LTGF-beta to smooth muscle cells is mediated by LAP, and the domain of LAP responsible for the targeting to smooth muscle cells may not be related to mannose-6-phosphate or an Arg-Gly-Asp sequence, both of which have been previously proposed as candidates for the cellular binding domains within LAP.

Amino Acid Sequence↗
PubMed1993

Brefeldin A protects ricin-induced cytotoxicity in human cancer KB cell line, but not in its resistant counterpart with altered Golgi structures.

Brefeldin A (BFA), an isoprenoid fungal metabolite, dramatically disrupts intracellular protein transport and protein secretion. BFA protects cells from the cytotoxicity of a plant toxin, ricin or pseudomonas toxin, but not that of diphtheria toxin (Yoshida et al., 1991. Expt. Cell Res., 192: 389-395.). In this study, we examined whether BFA could differentially change the cytotoxicity of ricin between BFA-sensitive cells and BFA-resistant cells. As a BFA-resistant cell line, we used a resistant cell line, KB/BF2-2, derived from BFA-sensitive human cancer KB cells. BFA treatment caused the disappearance of typical Golgi cisternae and the concomitant appearance of dilated vesicles in the cytoplasm in KB cells. By contrast, KB/BF2-2 cells had already altered Golgi structures with poor development of cisternae and also many vesicles in the absence of BFA, and BFA treatment did not further induce the morphological changes. Although a plasma membrane-specific marker protein, alpha-adaptin, was localized similarly in KB/BF2-2 as KB, Golgi specific markers such as beta-cop and gamma-adaptin were distributed in the cytoplasmic small vesicles as well as Golgi compartments in KB/BF2-2 cells in the absence of BFA, and the mutant cells showed no apparent changes in the distribution even when exposed to BFA. Ricin inhibited protein synthesis in KB and KB/BF2-2 to similar levels while pretreatment of KB cells with BFA at 0.1 microgram/ml almost completely reversed the inhibitory effect of ricin. By contrast, the pre-exposure of KB/BF2-2 cells to 1.0 microgram/ml BFA only partially rescued the ricin-induced inhibition of protein synthesis. Exposure to BFA at 30 min before ricin addition or at 0 min with ricin rescued the protein synthesis inhibition, but no rescue occurred when BFA was added 30 min after ricin addition. BFA could not rescue the protein synthesis inhibition by another toxin, diphtheria toxin. Our results suggest that BFA-resistant mutation causes a specific change in the endocytic membrane traffic of ricin in human cells, and also that cytotoxicity of diphtheria toxin does not share a common pathway of the intracellular transport with that of ricin.

Adaptor Protein Complex gamma Subunits↗
PubMed1992

Induction of low density lipoprotein receptor and a transcription factor SP-1 by tumor necrosis factor in human microvascular endothelial cells.

We have previously reported that tumor necrosis factor-alpha (TNF-alpha) enhances expression of interleukin-6, collagenase, plasminogen activator inhibitor-1, and basic fibroblast growth factor genes in human omental microvascular endothelial (HOME) cells in culture. In this study, we found that treatment of HOME cells with TNF-alpha or interleukin-1 (IL-1) caused enhanced expression of low density lipoprotein (LDL) receptor. A few-fold increase in both LDL binding activity and the receptor mRNA levels was observed when HOME cells were treated with either TNF-alpha or IL-1. Northern blot analysis showed that cellular expression of LDL receptor gene was significantly increased 12-24 h after exposure to TNF-alpha. No significant changes in the life-span of LDL receptor mRNA were observed in untreated and TNF-alpha-treated cells. Scatchard analysis showed an increased receptor number for LDL in TNF-alpha-treated cells. Parallel to increased LDL binding activity, internalization and degradation of LDL were also increased in HOME cells treated with TNF-alpha or IL-1. TNF-alpha-induced enhancement of LDL receptor gene expression was not observed when cycloheximide was present. Cellular mRNA level of SP-1 gene was increased about 3-4-fold at 12 h after treatment with TNF-alpha. Nuclear run-on assays showed increased transcription of LDL receptor gene as well as SP-1 gene by TNF-alpha. Gel retardation assay with the SP-1 consensus fragment showed that SP-1 binding activity was increased about 4-5-fold 12-24 h after treatment with TNF-alpha. NF-kB binding activity was also dramatically increased, but there is no NF-kB motif on the promoter for LDL receptor gene. The induction of LDL receptor by TNF might be mediated through a transcription factor, SP-1.

Base Sequence↗
PubMed1992

Brefeldin A-resistant mutants of human epidermoid carcinoma cell line with structural changes of the Golgi apparatus.

We have isolated brefeldin A (BFA)-resistant cell lines, KB/BF-1 and KB/BF-2, from the human epidermoid carcinoma KB cell line. The BFA-resistant phenotypes have been stably maintained for more than 3 months in the absence of BFA. KB/BF-1 and KB/BF-2 showed 10-30-fold higher resistance to cytotoxicity of BFA but were 2-3-fold more sensitive to monensin and nigericin, than KB cells. KB/BF-1 showed aberrant structures of the Golgi complex with poorly developed cisternae surrounded by many small vesicles. Immunocytochemical studies were done with antibodies against a Golgi-specific antigen (chronic rheumatoid arthritis antigen) and a coatomer subunit (beta-subunit for coat proteins of non-clathrin-coated vesicles). Golgi-specific markers were distributed into the small vesicles which were localized diffusedly in cytoplasm of KB/BF-1 cells. Such Golgi markers were observed in a strictly confined perinuclear region of the parental KB cells, whereas in the mutant cells the markers were distributed more diffusedly in dot-like structures at perinuclear regions. In addition, when exposed to BFA, the mutant and parental cells showed a different distribution of these markers. Synthesis and maturation of low density lipoprotein receptor showed apparently slower rates in processing of low density lipoprotein receptor in KB/BF-1 and KB/BF-2 cells than those observed in their parental KB cells. Protein secretion in KB/BF-1 and KB/BF-2 cells was about 30% less than that in KB cells. Much less inhibition by BFA on the secretion was observed in KB/BF-1 and KB/BF-2 cells. A BFA-resistant mutation in BFA-resistant KB cell lines appears to affect assembly of the Golgi apparatus as well as some Golgi-specific functions.

Brefeldin A↗
PubMed1992

Interleukin-6 activity in urine and serum in patients with bladder carcinoma.

To investigate the correlation between interleukin-6 and urothelial neoplasms, interleukin-6 activities in blood and urine samples of patients with bladder carcinoma were measured with a proliferation assay using an interleukin-6 dependent murine hybridoma clone, MH60.BSF2. A total of 43 patients and 15 normal volunteers were entered into this study. All of the patients were examined preoperatively and 26 were reexamined more than 6 days postoperatively to eliminate the effect of surgical injury on interleukin-6 secretion. The interleukin-6 titers in urine and serum increased in accordance with the progression of the tumor stage, and tumor removal induced a remarkable decrease in the titer of urinary interleukin-6. Although the interleukin-6-producing site has not been elucidated yet, our study suggests that interleukin-6 activity in bladder carcinoma patients may reflect the immunoreaction against the tumor in local urothelium.

Adult↗
PubMed1992

Cytogenetics of tumor cells from patients with nonfamilial renal cell carcinomas.

We analyzed cytogenetically 20 nonfamilial renal cell carcinomas, using a combined method of enzymatic technique and short-term culture with several passages. From 16 of the 20 patients, metaphase cells suitable for analysis were successfully obtained. Fourteen of the 16 patients demonstrated clonal chromosome aberrations which included missing Y chromosome in 8, gain of chromosome 7 in 7, an extra X chromosome in 4, translocation between chromosome 3 and other chromosomes in 4, deletion of the short arm of chromosome 3 in 2 and monosomy 3 in 2. Abnormalities of chromosome 7 and sex chromosomes were only numerical, and those are thought to be related to the neoplastic changes of various malignant tumors. Abnormalities of chromosome 3, however, were not only numerical but also structural, especially in the short arm, and those may be possibly associated with the genesis of renal cell carcinoma.

Adult↗
PubMed1992

Incidentally diagnosed renal cell carcinoma.

We analyzed the incidence, sex and age distribution, diagnostic methods and survival rate of incidentally detected renal cell carcinomas (RCCs) and compared these factors with those of symptomatic RCCs. Of 141 patients with RCC treated between 1980 and 1989, 44 cases (31.4%) were incidentally detected. Thirty-one of these 44 cases were diagnosed by abdominal ultrasonography. The age of the incidental cases was significantly higher than that of the symptomatic ones (p = 0.045), particularly in male patients (p = 0.049). The tumor size in incidental cases was smaller and tumor stage earlier (p less than 0.0001). Moreover, the grade of malignancy was significantly lower, and clear cell type tumors were more frequently detected in the incidental cases. No difference was observed between the survival rates of incidental and symptomatic cases with stage 1 or 2 tumors. Of the incidental cases with stage 1 or 2, however, no patient with a tumor 3 cm or less in diameter has died. In conclusion, abdominal ultrasonography is a useful tool to detect RCC at an early stage, and patients with a relatively small tumor tend to have a good prognosis.

Adult↗
PubMed1992

Contrasting effects of interferon-gamma and interleukin-4 on neopterin generation from human adherent monocytes.

The production of neopterin is closely correlated with activation of cell-mediated immunity. Neopterin appears to be produced by human macrophages specifically stimulated with interferon-gamma (IFN-gamma). Interleukin-4 (IL-4), a B and T stimulatory factor, has recently been shown to inhibit monocyte/macrophage functions, including the ability to suppress monocyte-generated cytokines. In this report we confirmed previous studies that identified the monocyte/macrophage as the main producing cell among human blood cells and that secretion is stimulated by IFN-gamma and lipopolysaccharides (LPS). IL-4 inhibits the generation of neopterin from unstimulated monocytes. This inhibitory effect was dose dependent and occurred at concentrations lower than 0.01 ng/ml. However, IL-4 had only a minimal inhibitory effect on LPS-induced generation of neopterin and could not reverse IFN-gamma-induced neopterin secretion from adherent monocytes. Furthermore, we report that LPS induced IFN-gamma production in monocyte culture. This production is strongly inhibited by IL-4 treatment. These findings indicate that IL-4 can regulate the synthesis of neopterin by adherent blood mononuclear cells and provide further evidence that LPS-induced neopterin in macrophages may act by IFN-gamma-independent mechanisms.

Biopterins↗
PubMed1991

Concanavalin A-induced suppressor cell activity in patients with renal cell carcinoma.

Concanavalin A (Con A)-induced suppressor cell activity against the proliferative response of autologous lymphocytes to phytohemagglutinin was examined in peripheral blood lymphocytes derived from 12 normal control subjects and 25 patients with renal cell carcinoma (RCC). The Con A-induced suppressor cell activity in patients with RCC (23.4 +/- 21.4%) was significantly higher than that in control subjects (9.7 +/- 10.7%, P less than 0.05). No significant difference between the degree of suppressor cell activity and stage of disease, grade of malignancy, or cell type was found, although the suppressor activity in patients with tumor microscopically infiltrated by lymphocytes was significantly higher than in patients without lymphocyte-infiltration into the tumor (P less than 0.05). Furthermore, compared with control subjects, Con A-induced suppressor activity in patients with high stage and in those with lymphocyte infiltration into the tumor was significantly higher (P less than 0.05 and P less than 0.01, respectively). In conclusion, because patients with RCC have high suppressor cell activity, abrogation of this activity may be necessary to treat the RCC.

Adult↗
PubMed1991

Rapid turnover of low density lipoprotein receptor in human monocytic THP-1 cells.

We examined whether human monocyte-derived macrophages had low density lipoprotein (LDL) receptors with a short life span. The human monocytic leukemia cell line, THP-1, was highly differentiated when treated with phorbol ester. LDL receptors degraded rapidly with half-lives of 3-4 h in THP-1 cells before phorbol ester treatment. During the transition into monocytic cells, expression of the LDL receptor gene was not affected. However, relative degradation rates of LDL receptors normalized by those of cellular total proteins were about twice as fast in phorbol ester-treated THP-1 cells compared to untreated cells.

Cell Differentiation↗
PubMed1991

The dysfunctional LDL receptor in a monensin-resistant mutant of Chinese hamster ovary cells lacks selected O-linked oligosaccharides.

The Chinese hamster ovary (CHO) cell line Monr31, which is resistant to the cytotoxic ionophore monensin, produces a receptor for the low density lipoprotein (LDL) that has a lowered binding affinity for LDL and is approximately 5 kDa smaller in size than the receptor from parental CHO cells. It has been proposed that the reduced size and affinity for LDL are associated with a reduced level of O-glycosylation of Ser/Thr residues in the receptor. To examine this possibility in more detail, both parental CHO and Monr31 cells were metabolically radiolabeled with [3H]glucosamine, and the labeled LDL receptors were purified by immunoprecipitation and identified by SDS-PAGE-fluorography. The Ser/Thr-linked oligosaccharides in the receptors from both parental CHO and Monr31 cells are mono- and desialylated species having the common core structure Gal beta 1-3GalNAc. The receptor from Monr31 cells, however, contains about one-third fewer Ser/Thr-linked oligosaccharides than the receptor from parental CHO cells. Analysis of the glycopeptides derived from the Monr31 cell LDL receptors indicates that they contain Ser/Thr-linked oligosaccharides only in the clustered domain and are missing Ser/Thr-linked oligosaccharides in the unclustered regions of the protein. Additionally, analysis of a human LDL receptor lacking the domain for attachment of the clustered Ser/Thr-linked oligosaccharides and expressed in both parental CHO and Monr31 cells indicated that the truncated human receptor from Monr31 cells is devoid of Ser/Thr-linked oligosaccharides. In contrast, the truncated human receptor produced by parental CHO cells contains Ser/Thr-linked oligosaccharides contributing approximately 5 kDa to its apparent size. Collectively, these results demonstrate that the LDL receptor produced by the Monr31 cells contains Ser/Thr-linked oligosaccharides in the clustered domain but is missing Ser/Thr-linked oligosaccharides in the unclustered, NH2-terminal domains of the receptor.

Acetylgalactosamine↗
PubMed1991

Comparison of lumbar flank approach and transperitoneal approach for radical nephrectomy.

A retrospective analysis based on Robson's tumor stage classification was performed on 56 patients with renal cell carcinoma who had undergone radical nephrectomy through a lumbar flank approach and 35 who had through a transperitoneal approach. The 5-year survival rates of patients with nephrectomy through the lumbar approach for Robson's stage 1, stage 2 and stage 3 were, respectively, 93.1, 70.4 and 60.0%. In comparison, the respective 5-year survival rates of patients with nephrectomy through the transperitoneal approach for Robson's stage 1, stage 2 and stage 3 were 90.5, 72.2 and 25.0%. As a result, there was no significant difference in survival rates between the two surgical procedures for any of the three Robson's stages. It is further suggested that the lumbar flank approach for radical nephrectomy does not result in poorer prognosis than does the transperitoneal approach, though transperitoneal and thoracoabdominal approaches have been generally recommended.

Adolescent↗
PubMed1991

Revascularization of the calcarine artery in moyamoya disease: OA-cortical PCA anastomosis--case report.

A 38-year-old male presented with moyamoya disease. Occlusion of the bilateral proximal posterior cerebral arteries (PCAs) resulted in homonymous 3/4 (right half and left lower quadrant) anopsia and various mental symptoms. To prevent impending cortical blindness, revascularization to the right PCA was performed by occipital artery (OA) to calcarine artery anastomosis. His neurological state was stabilized. OA-cortical PCA (calcarine artery) anastomosis is an alternative to omentum transplantation or occipital burr hole procedures for impending cortical blindness.

Adult↗
PubMed1991

[Usefulness and limitation of immunotherapy of metastatic renal cell carcinoma with autologous lymphokine-activated killer cells and interleukin 2].

Fourteen patients with metastatic renal cell carcinoma (RCC) were treated by systemic administration of autologous lymphokine-activated killer (LAK) cells and interleukin-2 (IL-2). Pulmonary metastases alone were found in 9 cases, pulmonary and mediastinal nodal metastases in 3, and pulmonary and bone metastases in 2. LAK cells, generated by incubation in 2 units/ml of IL 2 for 3-4 days, were intravenously administered once or twice a week. In addition, beginning on the day of the first LAK cell infusion, 1000 units of IL 2 diluted in normal saline were intravenously infused once or twice a day with occasional supplementation of 1000 units of IL-2 on each day of LAK cell infusion. The total number of LAK cells and total amount of IL-2 administered per patient in this study ranged from 0.8 x 10(10) to 6.9 x 10(10) cells and from 3.3 x 10(4) to 21.4 x 10(4) units, respectively. As toxic effects caused by the infusion of LAK cells, headache, shaking chills, fever and leukocytosis were found in all 14 cases. Side effects possibly induced by IL-2 infusion were tolerable fever, fluid retention (body weight gain of 2-3 kg) and eosinophilia. No objective regression of mediastinal nodal or bone metastases was observed. In regard to lung metastases, however, partial and minor responses were observed in 3 and 2 cases, respectively. One of the 3 patients with a partial response was clinically free of disease after undergoing a thoracotomy for resection of residual lesions, but a brain metastasis was detected 10 months after the thoracotomy. The remaining 2 patients are being closely followed up at present. In 3 of 11 patients who showed a minor response, no change or progressive disease, brain metastases were observed during or after the immunotherapy. Furthermore, we examined the possibility of selection of suitable candidates for this therapy on the basis of the degree of in vitro LAK activity against autologous cultured tumor cells in 6 patients, but there was no significant correlation between in vitro autologous tumor cell lysis by LAK cells and the clinical response to immunotherapy. In conclusion, although a complete response could not be obtained, it can be said that this immunotherapy may be effective against RCC, in particular lung metastases, since a partial response was achieved in 3 of 14 patients. However, it should be taken into consideration that this immunotherapeutic approach may have a risk of increasing the frequency of brain metastases.

Adult↗