Biomedical subjects

T Ohga

Publications and source records attributed to T Ohga.

At least 19 recordsLinked to original sources

PubMed2006

Laparoscopy-assisted right hepatic lobectomy using a wall-lifting procedure.

This article describes a new technique for performing a laparoscopy-assisted right hepatic lobectomy using a hanger wall-lifting procedure. The patient is placed in the left semi-lateral position. A cholecystectomy and hemi-hepatic vascular inflow control are then performed through a midline incision, through which the resected liver can be removed. Next, the right lower chest and right upper abdominal wall are lifted by two wires vertical to the abdominal wall. Two ports, a 5-mm port in right lateral abdomen for forceps and a 12-mm port just right of the umbilicus for the laparoscope, are inserted. The obtained view of the operative field in the right upper abdominal cavity is thus excellent. The laparoscopy-assisted mobilization of the right hepatic lobe is done with the assistance of a hand inserted through the midline incision, including a dissection of the hepato-renal ligament, the right triangular ligament, and the right coronary ligament. A parenchymal dissection is then performed using the Cavitron Ultrasonic Surgical Aspirator (CUSA) and the resected specimen is passed through the midline incision without any morcellation of the liver. This procedure can minimize the length of the wound, while avoiding the lethal complications associated with pneumoperitoneum.

Hepatectomy↗

PubMed2002

Clinicopathological features of early esophageal squamous cell carcinoma with subsequent recurrence.

It has been well known that there is occasionally a postoperative recurrence in early esophageal carcinoma. However, the clinicopathologic characteristics of early squamous cell carcinoma of the esophagus with a postoperative recurrence have not been elucidated. The subjects were 103 patients with early carcinoma of the esophagus including 10 patients with subsequent recurrence, who had been surgically treated. Clinicopathologic features were compared between patients with the presence and absence of recurrence of carcinoma. No special clinicopathologic feature was observed in early esophageal carcinomas with subsequent recurrence, when compared with early carcinomas without recurrence. Physicians should realize that there is always a possibility of recurrence in early carcinomas of the esophagus, and that a leading clinical strategy for superficial carcinoma of the esophagus is the surgical treatment.

Adult↗

PubMed2001

Significance of allogenic blood transfusion on decreased survival in patients with esophageal carcinoma.

BACKGROUND: To the authors' knowledge, the significance of allogenic blood transfusion in the prognosis of patients with esophageal carcinoma remains controversial. The objective of the current study was to elucidate the correlation, if any, between intraoperative allogenic blood transfusion and prognosis in patients with esophageal carcinoma. METHODS: Two hundred fifty-nine patients with esophageal carcinoma who had undergone esophagectomy and reconstruction were studied. The clinicopathologic data and survival were compared between the 87 patients (33.6%) who received an intraoperative allogenic blood transfusion and the 172 patients (66.4%) who did not. RESULTS: Multivariate analysis demonstrated that the factors that appeared to independently determine prognosis in patients with esophageal carcinoma were the depth of the tumor (P = 0.0001), lymph node metastasis (P < 0.0001), lymphatic invasion (P = 0.0002), venous invasion (P = 0.0008), and the occurrence of postoperative complications (P = 0.034). Intraoperative allogenic blood transfusion was not found to be an independent prognostic indicator. CONCLUSIONS: In the current study, an advanced stage of disease at the time of surgery, which resulted in the need for blood transfusion and the occurrence of postoperative complications, appeared to worsen the prognosis in patients with esophageal carcinoma.

Aged↗

PubMed2001

A novel variant of WISP1 lacking a Von Willebrand type C module overexpressed in scirrhous gastric carcinoma.

Scirrhous carcinoma of the stomach is characterized by rapid growth with a vast fibrous stroma, high invasiveness, and substantially a poor prognosis. Little is known of the molecular pathogenesis of this disease. Members of the emerging family of the CCN gene (for connective tissue growth factor, cysteine-rich 61, nephroblastoma overexpressed) encode cysteine-rich secreted proteins with roles in human fibrotic disorders and cancer progression. Using targeted differential displays, we identified a novel variant of the CCN family member WISP1 (Wnt-induced secreted protein 1), named WISP1v, as overexpressed in scirrhous gastric carcinomas. Predicted protein of the WISP1v completely lacks a module of Von Willebrand type C that is thought to participate in protein complex formation. Ectopic expression revealed WISP1v to be a secreted oncoprotein inducing a striking cellular transformation and rapid piling-up growth. It is noteworthy that WISP1v transfectants enhanced the invasive phenotype of co-cultured gastric carcinoma cells, while wild-type WISP1 had no such potential. These findings suggest that CCN protein WISP1v is involved in the aggressive progression of scirrhous gastric carcinoma.

3T3 Cells↗

PubMed2001

Clinicopathologic characteristics of esophageal squamous cell carcinoma in younger patients.

BACKGROUND: The aim of the current study was to find out the clinicopathologic characteristics of younger patients with squamous cell carcinoma of the esophagus. METHODS: A total of 259 patients with esophageal squamous cell carcinoma who had been treated by esophagectomy and reconstruction within 10 years between January 1990 and December 1999 were studied. Clinicopathologic characteristics were compared between 27 patients younger than 50 years and 232 patients 50 years and older. RESULTS: A significant difference was observed with regard to the size of the tumor (6.3 +/- 3.8 cm in younger patients versus 5.0 +/- 2.4 cm in older patients; p = 0.017). The proportion of patients with TNM stage III or IV in younger patients (59.3%, 16 of 27) was significantly higher than that in older patients (38.3%, 89 of 232; p = 0.020). Nevertheless, no significant difference in the 1-, 3-, and 5-year survival rates was observed between younger patients (77.2%, 54.7%, and 54.7%, respectively) and older patients (81.9%, 54.2%, and 48.8%, respectively). CONCLUSIONS: Although the prognosis of younger patients with esophageal squamous cell carcinoma did not differ from that of older patients, esophageal squamous cell carcinoma in younger patients has more malignant potential and aggressive activity.

Adult↗

PubMed1999

Transcription factor Y-box binding protein 1 binds preferentially to cisplatin-modified DNA and interacts with proliferating cell nuclear antigen.

The Y-box binding protein (YB-1) binds to inverted CCAAT box sequences that are present in the promoter region of many genes. We previously showed that YB-1 is overexpressed in human cancer cell lines that are resistant to cisplatin and that the depletion of YB-1 by transfection of a vector expressing YB-1 antisense RNA increases the sensitivity of human cancer cells to cisplatin. To determine whether YB-1 can bind to cisplatin-modified DNA, we fused YB-1 cDNA to glutathione S-transferase (GST) cDNA and purified the resulting GST fusion protein. When we tested the fusion protein with unmodified or cisplatin-modified oligonucleotides, we found that GST-YB-1 bound more strongly to cisplatin-modified oligonucleotides, as did GST fusion proteins of high mobility group 1 (HMG1), HMG2, and xeroderma pigmentosum group A protein. When we assayed the ability of proliferating cell nuclear antigen (PCNA) to interact with the GST fusion proteins, we observed binding to YB-1 but not to HMG1, HMG2, or xeroderma pigmentosum group A. Subsequent experiments demonstrated that YB-1 and PCNA interact directly via the COOH-terminal region of YB-1. Using immunochemical coprecipitation methods, we observed binding of YB-1 and PCNA in vivo. These results suggest that YB-1 can function as a recognition protein for cisplatin-damaged DNA and that it may be important in DNA repair or in directing the cellular response to DNA damage.

CCAAT-Enhancer-Binding Proteins↗

PubMed1999

Esophageal carcinoma showing a long stricture due to prominent lymphatic permeation: report of a case.

Some esophageal diseases such as carcinoma, esophagitis, and collagen diseases have often been reported to show a diffusely thickened esophageal wall in the roentogenogram findings. In the current report, a preoperative upper gastrointestinal series and an endoscopic examination showed a diffusely infiltrative type carcinoma, but other examinations did not suggest any diseases such as esophagitis or collagen diseases which might cause a thickening of the esophageal wall or a constriction of the esophagus. A postoperative histological examination revealed the primary carcinoma to remain only within the mucosal layer, while a large degree of lymphatic vessel permeation reached the adventitia over a wide area. An extraordinary degree of lymphatic permeation spread through the esophageal wall, and stromal fibrosis developed as a result of such lymphatic permeation. These histological phenomena might thus have led to the macroscopic appearance of infiltrative type esophageal carcinoma.

Carcinoma, Squamous Cell↗

PubMed1998

Direct involvement of the Y-box binding protein YB-1 in genotoxic stress-induced activation of the human multidrug resistance 1 gene.

The human multidrug resistance 1 (MDR1) gene encoding P-glycoprotein is often overexpressed in various human tumors after chemotherapy. During treatment with various chemotherapeutic agents, the MDR1 gene is activated at the transcriptional level and/or amplified, resulting in overexpression. Our previous studies demonstrated that an inverted CCAAT box (Y-box) might be a critical cis-regulatory element regulating UV or drug-induced MDR1 gene expression. We have now established various cell lines from human head and neck cancer KB cells which were stably transfected with the chloramphenicol acetyltransferase (CAT) reporter gene driven by various MDR1 promoter deletion constructs. Transient transfection of antisense YB-1 expression constructs resulted in a decrease of both YB-1 protein levels and DNA binding activity to the inverted CCAAT box, as determined by Western blot and gel mobility shift assays. The limited expression and binding activity due to expression of antisense YB-1 constructs were also observed when cells were treated with UV. CAT activity of constructs containing the Y-box was enhanced after treatment with UV irradiation as well as genotoxic agents such as cisplatin and etoposide. Moreover, this activation was reduced by 50-80% by transfection of antisense YB-1 expression constructs. In contrast, transfection of antisense YB-1 expression constructs had no effect on CAT activity driven by MDR1 promoter constructs not containing the Y-box. These data indicate that YB-1 is directly involved in MDR1 gene activation in response to genotoxic stress.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1998

Genomic organization of the human Y-box protein (YB-1) gene.

The human Y-box protein (YB-1) is a member of a family of DNA-binding proteins containing a highly conserved cold shock domain. The genomic organization of the human YB-1 gene was determined from five overlapping genomic clones that encompassed all exons of the gene. Sequence analysis of these clones revealed that human YB-1 spans approximately 19 kb of genomic DNA and contains eight exons. The cold shock domain is encoded by exons 1-5. Both exon-splitting and codon-splitting in the region of the gene encoding the cold shock domain are similar to those in the corresponding region of another Y-box binding protein, dbpA. Exon-intron structures and nucleotide sequences of the regions encoding the N-terminal and C-terminal domains of the two proteins differ markedly between YB-1 and dbpA. These observations suggest that YB-1 and dbpA arose by duplication of a common ancestral gene encoding all these domains.

Base Sequence↗

PubMed1998

Abdominal incisional hernia occurring after an esophagectomy reconstructed with a gastric tube through an antesternal route: report of a case.

A Japanese man, who had undergone a subtotal esophagectomy reconstructed with a gastric tube through an antesternal route for esophageal carcinoma 16 years previously, was admitted to our hospital because of an abdominal incisional hernia. The abdominal incisional hernia was in his upper abdomen and was difficult to push back into the intraabdominal cavity by hand. The hernia was successfully repaired by operation. We thus conclude that an abdominal incisional hernia is a rare but important late-phase complication occurring after an esophagectomy reconstructed with either an antesternal or retrosternal route, and an operation should be the treatment of choice.

Aged↗

PubMed1998

Nuclear expression of YB-1 protein correlates with P-glycoprotein expression in human osteosarcoma.

The Y-box-binding protein, YB-1, is a member of the DNA-binding protein family. It binds to the Y-box, an inverted CCAAT box, in the promoter region of the human multidrug resistance 1 gene, which encodes P-glycoprotein (P-gp). Nuclear localization of YB-1 protein has been reported to be associated with the intrinsic expression of P-gp in human breast cancer. We studied the immunohistochemical expression of YB-1 protein in 69 untreated biopsy specimens of conventional osteosarcomas and compared it with the expression of P-gp. Furthermore, cell proliferation, as determined by the MIB-1-labeling index (MIB-1-LI), was measured by immunohistochemistry. In all 69 untreated osteosarcomas, YB-1 protein was expressed in the cytoplasm. In 32 of 69 (46%) cases, YB-1 was also localized in the nucleus. The expression of P-gp was evident in 23 of these 32 cases, and there was a significant correlation between the nuclear expression of YB-1 and P-gp expression (P < 0.0001). Chondroblastic osteosarcoma expressed YB-1 in the nucleus more frequently (eight of nine cases) than did other types of osteosarcoma, whereas P-gp was also frequently expressed in chondroblastic subtype. There was no correlation between the nuclear expression of YB-1 and histological grade. The MIB-1-LI was significantly higher in cases showing the nuclear expression of YB-1 (MIB-1-LI averaged 22.56 in cases with only cytoplasmic expression of YB-1 but averaged 28.20 in cases with cytoplasmic and nuclear expression of YB-1; P = 0.0477). In human osteosarcoma, nuclear localization of YB-1 protein was associated with the expression of P-gp, suggesting that YB-1 could be a prognostic marker for multidrug resistance in osteosarcoma.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1997

Nuclear translocation of the Y-box binding protein by ultraviolet irradiation.

The Y-box binding protein, YB-1, is a member of a DNA binding protein family with a structurally and functionally conserved cold shock domain. Using Western blotting and immunohistochemical methods, larger amounts of YB-1 were detected in the cytosol, particularly at the perinuclear region, than in the nucleus of human cancer cells. UV irradiation increased accumulation of YB-1 in the nucleus at 20 min and thereafter. This translocation of YB-1 into the nucleus by UV irradiation was blocked by the protein kinase inhibitor H-7, but not HA-1004. Both green fluorescent protein (GFP)-YB-1 and GFP-YB-1C with the C-terminus (248-317) of YB-1 were located mainly in the cytosol, but GFP-YB-1deltaC with a deletion at the C-terminus of YB-1 was located in the nucleus. YB-1 is translocated into the nucleus by UV irradiation, possibly through a protein kinase C-mediated signal transduction pathway, and the C-terminal region of YB-1 might be important for cytoplasmic retention of YB-1.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗

PubMed1997

Friedreich-like ataxia with retinitis pigmentosa caused by the His101Gln mutation of the alpha-tocopherol transfer protein gene.

The alpha-tocopherol transfer protein (alpha-TTP) is a cytosolic liver protein that is presumed to function in the intracellular transport of alpha-tocopherol, the most biologically active form of vitamin E. We studied 4 unrelated patients with autosomal recessive Friedreich-like ataxia who had isolated vitamin E deficiency. A point mutation was identified in all of them at position 101 of the gene for alpha-TTP, where histidine (CAT) was replaced with glutamine (CAG). Three of the 4 patients developed retinitis pigmentosa subsequent to the onset of ataxia. Neurological symptoms included ataxia, dysarthria, hyporeflexia, and decreased proprioceptive and vibratory sensations. Electrophysiological and pathological examinations showed that the cardinal sites affected were the central axons of dorsal root ganglion cells and the retina, with minor involvement of the peripheral sensory nerve, optic nerve, and pyramidal tract. The vitamin E tolerance test performed showed that the absorption of vitamin E was normal but that its decrease from the serum was accelerated. Oral administration of vitamin E appeared to halt the progression of visual and neurological symptoms. We propose a new treatable syndrome of Friedreich-like ataxia and retinitis pigmentosa caused by a defect in the alpha-TTP gene.

Aged↗

PubMed1997

[Long-term results of preoperative hyperthermo-chemo-radiotherapy (HCR) for patients with esophageal carcinoma invading neighboring structures (T4)].

PATIENTS: A total of 180 patients with esophageal carcinoma invading the neighboring structures (T4) were surgically treated by esophagectomy and reconstruction in the Department of Surgery II, Kyushu University from January 1965 to April 1997. Any of these cases with distant node metastasis and demonstrating organ metastasis or a combined resection of adjacent structures were excluded from this study. As a result, twenty-six patients treated with preoperative hyperthermo-chemo-radiotherapy (HCR Group), 39 treated either with preoperative radiotherapy or preoperative chemo-radiotherapy (R or CR Group) and 23 non-treated patients (Non-tx Group) were thus entered in this study. RESULTS: The 3-year survival rates after esophagectomy in HCR Group, R or CR Group and Non-tx Group were 26.5%, 0% and 9%, respectively, while the 5-year survival rate of the HCR group was 15.9%. The group with preoperative HCR thus showed a significantly more favorable outcome than R or CR Group and Non-tx Group. (p < 0.05). DISCUSSION: The significant difference observed in the prognosis was thought to be due to the reinforced effect of local regulation due to hyperthermia. Our data thus suggest that preoperative HCR contributes to the prolonged post-operative survival for carcinoma of the esophagus invading the neighboring structures.

Aged↗

PubMed1996

Role of the human Y box-binding protein YB-1 in cellular sensitivity to the DNA-damaging agents cisplatin, mitomycin C, and ultraviolet light.

The Y box-binding protein (YB-1) binds to DNA sequences, present in the control regions of many genes, that contain an inverted CCAAT box. The binding activity of a nuclear factor, designated MDR-NF1, to an inverted CCAAT box in the promoter of the multidrug resistance 1 (MDR1) gene has previously been shown to be increased in nuclear extracts of cells exposed to UV radiation or various anticancer agents. The MDR-NF1 cDNA has now been cloned by screening a human colon library with an active fragment of the MDR1 promoter. The amino acid sequence encoded by the cloned cDNA was identical to that of YB-1. Northern blot analysis revealed that YB-1 mRNA was present in all human tissues examined. Rabbit antibodies were generated against synthetic peptides corresponding to YB-1, and indirect immunofluorescence microscopy with these antibodies showed that the concentration of YB-1 in all cisplatin-resistant cell lines examined was higher than that in the respective drug-sensitive parental cells. Transfection of human epidermoid cancer KB cells with a YB-1 antisense construct established two cell lines with reduced concentrations of YB-1. These transfectants showed increased sensitivity to cisplatin, mitomycin C, and UV radiation but not to vincristine, doxorubicin, camptothecin, or etoposide. Thus, YB-1 may protect cells from the cytotoxic effects of agents that induce cross-linking of DNA, suggesting a novel function of this ancestor DNA-binding protein.

Amino Acid Sequence↗

PubMed1996

Structural and functional analysis of the human Y-box binding protein (YB-1) gene promoter.

We have isolated three overlapping genomic clones containing the 5'portion of the human YB-1 gene. These clones span approximately 25 kb of contiguous DNA containing 10 kb of 5' flanking sequence and 15 kb of the gene. The nucleotide sequence of the first exon and of 2000 upstream base pairs (bp) was determined. The first axon is unusually large and contains a 166 bp coding sequence and a 331 bp untranslated region. CpG sequences cover the 5'-end of the YB-1 gene including its first axon and intron as well as the upstream regions. The GC content around the first exon is approximately 70% and a CpG-free region was located in the untranslated sequence. The segment preceding the major transcription initiation site does not contain a TATA box, CCAAT box and the binding sequence for known transcription factors. A transient expression assay using the chloramphenicol acetyltransferase (CAT) gene showed that the sequence from +24 to +281 was critical for CAT expression. Fluorescence in situ hybridization demonstrated the chromosomal locus of YB-1 gene on chromosome 1p34. Polymerase chain reaction analysis on other genomic phage DNAs showed that several clones were derived from pseudogenes.

Base Composition↗

PubMed1995

Cellular levels of thioredoxin associated with drug sensitivity to cisplatin, mitomycin C, doxorubicin, and etoposide.

Thioredoxin, a cellular thiol, functions as a self-defense mechanism in response to environmental stimuli, including oxidative stress. We first determined cellular levels of thioredoxin in several human bladder and prostatic cancer cell lines resistant to cis-diamminedichloroplatinum(II) (cisplatin). All cisplatin-resistant cell lines had much higher levels of thioredoxin than those in their drug-sensitive parental counterpart. We then, by introducing thioredoxin antisense expression plasmids into human bladder cancer T24 cells, established two bladder cancer cell lines that had decreased levels of thioredoxin. These thioredoxin antisense transfectants showed increased sensitivity to cisplatin and also to other superoxide-generating agents, i.e., doxorubicin, mitomycin C, etoposide, and hydrogen peroxide, as well as to UV irradiation, but not to the tubulin-targeting agents, vincristine, and colchicine. Cellular levels of thioredoxin thus appear to limit sensitivity to various superoxide-generating anticancer drugs in cancer cells.

Antineoplastic Agents↗

PubMed1995

DNA topoisomerase II alpha gene expression under transcriptional control in etoposide/teniposide-resistant human cancer cells.

We previously isolated etoposide/teniposide-resistant cell lines from human cancer KB cells, designated KB/VP-2 and KB/VM-4, respectively, and we found that decreased expression of topoisomerase II alpha was associated with the acquisition of etoposide/teniposide resistance in both resistant cell lines. In this study, we studied how the expression of the DNA topoisomerase II alpha gene is regulated in drug-resistant cell lines at the transcriptional level. We first examined whether the decreased topoisomerase II alpha mRNA level was due to a shorter lifetime of mRNA molecules in drug-resistant cell lines. A comparison of the degradation kinetics of topoisomerase II alpha mRNA demonstrated that there was no difference in mRNA stability between both resistant cell lines and their parental counterpart. A run-on experiment with isolated nuclei showed that the transcriptional activity of topoisomerase II alpha gene of both resistant cell lines constituted less than 20% of the parental KB cells. The activity of DNA topoisomerase II alpha promoter in resistant cells was also less than 20% of that in KB cells when transient transfection assays were performed with the promoter-driven bacterial chloramphenicol acetyltransferase gene. Among the several transcription factors that might be involved in DNA topoisomerase II alpha gene expression, expression of Sp3, an inhibitory member of the Sp1 family, was elevated to about 3-fold higher in both resistant cell lines than their parental counterpart. These results indicated that the expression of DNA topoisomerase II alpha gene decreased at the transcriptional level through the enhanced expression of Sp3 in our two etoposide/teniposide-resistant cell lines.

Antigens, Neoplasm↗