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Biomedical subjects

K Ueki

Publications and source records attributed to K Ueki.

At least 19 recordsLinked to original sources

Correlation between thymidine phosphorylase expression and invasion phenotype in cervical carcinoma cells.

The correlation between thymidine phosphorylase (dThdPase) expression and invasion phenotype in human uterine cervical carcinoma cells was investigated using 10 cervical carcinoma cell lines. Semi-quantitative reverse transcription-polymerase chain reaction analysis was performed to investigate the mRNA levels of dThdPase and matrix metalloproteinase (MMP)-2 with beta-actin coamplified as an internal standard. dThdPase protein expression levels were detected by highly sensitive enzyme-linked immunosorbent assay. Tumor cell migration along a gradient of substratum-bound fibronectin and invasion into reconstituted basement membrane were evaluated by haptotactic migration and invasion assay. Although dThdPase mRNA and protein expression levels differed remarkably among the cell lines, there was a statistical correlation between them (r = 0.743, p = 0.0139). dThdPase gene and protein expression levels were well correlated with the number of cells that migrated and invaded (p < 0.05). Moreover, there was a close correlation between MMP-2 gene and dThdPase gene and protein expression levels (p < 0.05). Tumor cells that produce dThdPase may have a higher invasive and metastatic potential because of their capacity to pass through tissue barriers.

Carcinoma, Squamous Cell↗

Silencing of the caspase-1 gene occurs in murine and human renal cancer cells and causes solid tumor growth in vivo.

Renal cell cancer is a unique solid tumor that occasionally shows spontaneous regression even at an advanced stage, of which the underlying mechanism is not well understood. To investigate a potential role of the pro-apoptotic molecule caspase-1 in the growth regulation of renal cell cancer, we created transfectants expressing exogenous caspase-1 from a murine renal cancer cell line, Renca. Overexpression of caspase-1 did not affect the growth of Renca cells in vitro at the exponential phase but induced apoptotic cell death at 50% to 75% confluence, whereas control cells underwent apoptosis only after reaching 100% confluence. When implanted into the flank of a syngeneic BALB/c mouse, caspase-1-overexpressing Renca cells did not effectively establish growth as a solid tumor, forming a measurable tumor in only 7 of 11 (64%) animals, whereas control cells formed a tumor in 6 of 6 (100%) animals. The growth of tumors from caspase-1-overexpressing cells slowed down markedly after the tumors reached 5 to 10 mm in diameter, and histological examination of such tumors revealed numerous apoptotic cells positively stained by TUNEL assay. Interestingly, endogenous caspase-1 was not detected in the tumors from control cells, which re-expressed caspase-1 when they were re-cultured and exposed to a demethylation reagent, 5-aza-2'-deoxycytidine. Furthermore, treatment of a human renal cancer cell line, ACHN, with 5-aza-2'-deoxycytidine also caused recovery of caspase-1 expression, which was not detected before treatment. These data suggest that silencing of caspase-1 through DNA methylation may be involved in the oncogenesis of some renal cell cancers growing as a solid tumor.

Animals↗

Vascular endothelial growth factor C gene expression is closely related to invasion phenotype in gynecological tumor cells.

OBJECTIVE: The correlation between the gene expression of various angiogenic factors and in vitro invasive activity in 16 human gynecological cancer cell lines was investigated. METHODS: Semiquantitative reverse transcription polymerase chain reaction analysis was performed to investigate the mRNA expression levels of vascular endothelial growth factors (VEGF-A, -B, -C, and -D), basic fibroblast growth factor (bFGF), and matrix metalloproteinase (MMP)-2 with beta-actin coamplified as an internal standard. Tumor cell migration along a gradient of substratum-bound fibronectin and invasion into reconstituted basement membrane were evaluated by haptotactic migration and invasion assay. RESULTS: Expression of VEGF-A mRNA was detected in all 16 cell lines, whereas the relative expression levels of other VEGF family members and bFGF, differed markedly among the cell lines. There was a statistical correlation between VEGF-C gene expression and the number of cells that migrated and invaded (P < 0.01). However, expression of mRNAs of other angiogenic factors did not correlate with motility and invasive activity of the cells. Moreover, there was a close correlation between VEGF-C and MMP-2 gene expression levels (P < 0.05). CONCLUSION: Tumor cells that produce VEGF-C may have a higher invasive and metastatic potential because of their capacity to pass through tissue barriers.

DNA, Neoplasm↗

Insulin-independent and wortmannin-resistant targeting of IRS-3 to the plasma membrane via its pleckstrin homology domain mediates a different interaction with the insulin receptor from that of IRS-1.

AIMS/HYPOTHESIS: In primary adipocytes, although IRS-1 and IRS-3 are expressed in comparable amounts, these proteins manifest distinct distribution and significance in insulin signalling. We investigated the molecular basis of the difference between these two proteins. METHODS: In Cos-1 cells transiently expressing rat IRS-1, IRS-3, or chimeric proteins of these two proteins we examined the tyrosine phosphorylation via the wild-type or mutant insulin receptors and evaluated their targeting to the plasma membrane by immunostaining the membrane ghost. RESULTS: In contrast to IRS-1, IRS-3 was tyrosine-phosphorylated by the insulin receptor altering Tyr960 to Phe (Y960F), which disrupts the binding site of the PTB domain of IRSs, to an extent comparable to the wild-type receptor. The tyrosine phosphorylation of IRS-3 with the PH domain replacement via the Y960F insulin receptor markedly decreased, whereas that of IRS-3 with the PTB domain alteration was mildly impaired. Insulin-stimulated translocation of IRS-1 to the plasma membrane, as well as that of IRS-3 with the PH domain replacement, was wortmannin-sensitive, although that of IRS-3 was insulin-independent and wortmannin-resistant. CONCLUSIONS/INTERPRETATION: The affinity of the PH domain for the phospholipids in the plasma membrane seems to influence the receptor-substrate interaction required for IRS tyrosine phosphorylation, indicating that the PH domain and the PTB domain of IRSs cooperatively function in insulin-stimulated tyrosine phosphorylation of these proteins.

Androstadienes↗

Incidence of von Hippel-Lindau disease in hemangioblastoma patients: the University of Tokyo Hospital experience from 1954-1998.

BACKGROUND: Incidence of von Hippel-Lindau disease among hemangioblastomas is important clinical information affecting the management of hemangioblastomas. Studies from Western countries reported 36-40% for the incidence, but no report has been made on the Japanese population. METHOD: To investigate the incidence in Japan, we retrospectively analyzed all hemangioblastoma patients treated at The University of Tokyo Hospital from 1954 to 1998. By reviewing medical records and imaging studies, von Hippel-Lindau disease was diagnosed clinically following the currently suggested diagnostic criteria. FINDINGS: There were 82 hemangioblastoma patients recorded during the period, and 14 cases (17%) were compatible with von Hippel-Lindau disease. However, when the incidence was calculated for each of the three 15-year periods, which are 1954-1968 (first), 1969-1984 (second), and 1985-1998 (third), the number increased dramatically in the later periods: 2 of 33 (6%) during the first, 4 of 26 (15%) during the second, and 8 of 22 (36%) during the third period. Such increase occurred after the introduction of whole body CT to our institution in 1981, suggesting that improvement of imaging techniques contributed to the sensitivity of diagnosis. In addition, one recent patient with multiple hemangioblastomas was found to harbor germline mutation of the VHL, thereby being diagnosed as von Hippel-Lindau disease on the basis of molecular genetics. INTERPRETATION: The 40% incidence of von Hippel-Lindau disease in hemangioblastomas suggests that extensive screening for von Hippel-Lindau disease associated neoplasms, and probably molecular genetic examination, is indicated for all patients with hemangioblastomas, which should aim for earlier diagnosis and better management of this devastating hereditary disease.

Adolescent↗

Clinical features and medical treatment of male prolactinomas.

BACKGROUND: Prolactinomas found in male patients show distinct clinical features compared to those in female patients, which may warrant a different treatment strategy. METHOD: To clarify their clinical features and to evaluate the treatment results, specifically the results of surgical treatment and non-surgical treatment solely with oral bromocriptine, we retrospectively reviewed our experience in male prolactinoma cases. FINDINGS: From 1988 to 1998, we had 184 pituitary adenoma patients, and thirteen of those were male patients with a pure prolactinoma. Of the thirteen patients, eight underwent transsphenoidal surgery followed by oral bromocriptine (surgical group), and five were treated solely with bromocriptine or terguride (non-surgical group). In both groups, the visual symptoms and signs resolved after the treatment, and the serum prolactin levels were normalised with minimal maintenance dose of bromocriptine. Notably, improvement of the visual symptom in the three non-surgically treated patients was observed within a week following the bromocriptine administration. INTERPRETATION: Although surgery would continue to play an important part of treatment in some cases with a large tumour, our experience suggests that drug treatment without surgery can be a safe and effective option in the management of male prolactinoma patients.

Adult↗

Congestive brain oedema associated with a pial arteriovenous malformation with impaired venous drainage.

We describe two patients with an unruptured pial AVM accompanied by significant brain oedema at initial presentation. In both cases, the primary drainer was a cortical vein showing varicose dilatation. in which venous congestion was indicated by magnetic resonance imaging (MRI). The restriction of venous drainage presumably caused venous hypertension in the surrounding brain, leading to the brain oedema and neurological symptoms. Brain oedema can develop in patients with an unruptured AVM by venous congestion following spontaneous thrombosis of venous components. Varicosity in a major cortical draining vein and a small nidus are the possible lesions predisposing this fairly rare condition for unruptured AVMs.

Adolescent↗

Interleukin-10 gene promoter polymorphism in Japanese patients with adult and early-onset periodontitis.

BACKGROUND: IL-10 is an anti-inflammatory cytokine, which may modulate disease expression in chronic inflammatory periodontal disease. 3 dimorphic polymorphisms within the IL-10 gene promoter have recently been identified and appear to influence regulation of its expression. AIM: The aim of the present study was to investigate whether the promoter polymorphisms are associated with adult periodontitis (AP) and generalized early-onset periodontitis (G-EOP). METHODS: Genomic DNA was obtained from 34 AP patients, 18 G-EOP patients and 52 controls. The promoter region between -506 and -1140 was amplified by polymerase chain reaction, and polymorphisms were detected by nucleotide sequencing. RESULTS: The haplotype frequencies in Japanese were quite different from those of Caucasian and were even slightly different from those of southern Chinese with systemic lupus erythematosus. We found no significant difference in allele or haplotype frequencies between patients and controls. CONCLUSIONS: IL-10 production may be regulated within the complex cytokine network in chronic inflammatory periodontal disease, rather than the gene polymorphisms.

Adult↗

Reduced urinary excretion of intact osteopontin in patients with IgA nephropathy.

Osteopontin (OPN) is a phosphoprotein secreted by many cells of epithelial, mesenchymal, and hematopoietic origin. In the kidney, OPN is expressed in the renal tubules and collecting ducts and is excreted into the urine. A pathophysiologic role for urinary OPN has not been established. In this study, urinary excretion of OPN was analyzed in patients with primary glomerular diseases, including immunoglobulin A nephropathy (IgAN; n = 32), minimal change nephrotic syndrome (MCNS; n = 16), and membranous nephropathy (MN; n = 18). Compared with normal controls (n = 20), mean +/- SD of urinary OPN in IgAN patients was decreased significantly (21.4 +/- 6.2 versus 11.6 +/- 9.6 mg/g creatinine, P: < 0.001). In contrast, the levels of urinary OPN in patients with MCNS or MN did not differ significantly from normal values. Immunoblot analysis showed that OPN is present as a 55- to 60-kd molecule in normal urine. A 34-kd fragment of OPN was the major immunoreactive band in samples from IgAN patients. This fragment also was detectable in the urine from some patients with MCNS or MN but was absent in normal subjects. OPN has a thrombin-cleavage site near its central portion. Thrombin treatment of the urine from normal controls could result in 34-kd OPN fragments. Although the underlying mechanisms remain to be determined, these data provide evidence that secretion or processing (or both) of urinary OPN is altered in patients with IgAN.

Adult↗

Plate fixation after mandibular osteotomy.

Skeletal asymmetry in patients who undergo orthognathic surgery is frequently associated with postoperative temporomandibular joint (TMJ) disorders caused by condylar rotation. This study was designed to elucidate the relation between changes in the condylar long axis and TMJ function after bisagittal split osteotomy (BSSO). A total of 42 patients with mandibular prognathism underwent BSSO. Split osseous fragments were secured by standard titanium plates in 22 patients; bent titanium plates were used to secure fragments in 20 patients. The angle of the bent plates was adjusted to avoid displacement of the condyle after osteotomy, as compared with condylar position on preoperative submental-vertical (S-V) cephalograms. The postoperative position of the condyle was assessed on X-ray film, and changes in TMJ function were evaluated. The condylar long axis differed significantly on X-ray film between patients using a standard titanium plate and those using a bent plate (P<0.05), and no sign of TMJ functional impairment was noted in the bent-plate group. Although the use of bent plates requires further study, maintenance of a suitable position of the condyle relative to the condylar axis is one of the conditions for a successful outcome of BSSO.

Analysis of Variance↗

Somatosensory-evoked potential to evaluate the trigeminal nerve after sagittal split osteotomy.

OBJECTIVE: The purpose of this study was to assess the onset period of trigeminal nerve hypoesthesia during bilateral sagittal split osteotomy, with the use of the trigeminal somatosensory-evoked potential (TSEP). STUDY DESIGN: Subjects were 10 patients with mandibular prognathism who underwent setback surgery. Intraoperative TSEP was measured 4 times: just before the commencement of the surgery, immediately after the induction of general anesthesia; after the medial periosteal dissection of the alveolar neurovascular bundle; after the sagittal split of bone; and after semirigid fixation with a titanium miniplate with the use of a monocortical screw. Postoperative TSEP was measured after the start of postoperative weeks 2, 4, 12, and 24. Normal records of the TSEP wave comprised peak (13 ms), trough (16 ms), peak (22.7 ms), and trough (36 ms) (N1, P1, N2, P2, respectively). Trigeminal hypoesthesia was assessed by the latency of P1 and N2, because they indicated the most reproducible waveforms. RESULTS: The change in shape of the spectra indicated that prolonged latency was initiated on medial periosteal dissection and was extended further after the sagittal bone split and fixation. However, latency recovery was observed relatively quickly after the start of postoperative weeks 2 and 4. CONCLUSIONS: Trigeminal hypoesthesia appeared to be induced by direct injury to the alveolar nerve during the bone split or by compression injury after fixation. Accordingly, the occurrence of a long-lasting postoperative trigeminal sensory hypoesthesia seemed to depend on nervous involvement of the split surface, the manner of fixation, or the intraoperative care.

Adolescent↗

Advanced peritonitis and subclinical disseminated intravascular coagulopathy associated with Chlamydia trachomatis infection.

A 29-y-old woman was admitted to our hospital complaining of slight fullness of the lower abdomen. Ultrasound echographic study and magnetic resonance imaging showed pleural effusion and pelvic ascites. Laboratory investigation revealed anemia and thrombocytopenia (hemoglobin 6 mmol/l; platelets 7 x 10(10)/l), remarkable polyclonal hypergammopathy (gamma immunoglobulin 7.7 g/dl) and subclinical disseminated intravascular coagulopathy (DIC). By laparoscopy, extensive adhesion of the peritoneum and bilateral ovarian tubes was observed. From the appearance of adhesion, we suspected Chlamydia trachomatis infection and performed serologic and molecular studies. Administration of clarithromycin resolved hypergammopathy, DIC and ascites.

Adult↗

Insulin receptor substrate 3 (IRS-3) and IRS-4 impair IRS-1- and IRS-2-mediated signaling.

To investigate the roles of insulin receptor substrate 3 (IRS-3) and IRS-4 in the insulin-like growth factor 1 (IGF-1) signaling cascade, we introduced these proteins into 3T3 embryonic fibroblast cell lines prepared from wild-type (WT) and IRS-1 knockout (KO) mice by using a retroviral system. Following transduction of IRS-3 or IRS-4, the cells showed a significant decrease in IRS-2 mRNA and protein levels without any change in the IRS-1 protein level. In these cell lines, IGF-1 caused the rapid tyrosine phosphorylation of all four IRS proteins. However, IRS-3- or IRS-4-expressing cells also showed a marked decrease in IRS-1 and IRS-2 phosphorylation compared to the host cells. This decrease was accounted for in part by a decrease in the level of IRS-2 protein but occurred with no significant change in the IRS-1 protein level. IRS-3- or IRS-4-overexpressing cells showed an increase in basal phosphatidylinositol 3-kinase activity and basal Akt phosphorylation, while the IGF-1-stimulated levels correlated well with total tyrosine phosphorylation level of all IRS proteins in each cell line. IRS-3 expression in WT cells also caused an increase in IGF-1-induced mitogen-activated protein kinase phosphorylation and egr-1 expression ( approximately 1.8- and approximately 2.4-fold with respect to WT). In the IRS-1 KO cells, the impaired mitogenic response to IGF-1 was reconstituted with IRS-1 to supranormal levels and was returned to almost normal by IRS-2 or IRS-3 but was not improved by overexpression of IRS-4. These data suggest that IRS-3 and IRS-4 may act as negative regulators of the IGF-1 signaling pathway by suppressing the function of other IRS proteins at several steps.

3T3 Cells↗

Essential role of insulin receptor substrate 1 in differentiation of brown adipocytes.

The most widely distributed members of the family of insulin receptor substrate (IRS) proteins are IRS-1 and IRS-2. These proteins participate in insulin and insulin-like growth factor 1 signaling, as well as the actions of some cytokines, growth hormone, and prolactin. To more precisely define the specific role of IRS-1 in adipocyte biology, we established brown adipocyte cell lines from wild-type and IRS-1 knockout (KO) animals. Using differentiation protocols, both with and without insulin, preadipocyte cell lines derived from IRS-1 KO mice exhibited a marked decrease in differentiation and lipid accumulation (10 to 40%) compared to wild-type cells (90 to 100%). Furthermore, IRS-1 KO cells showed decreased expression of adipogenic marker proteins, such as peroxisome proliferator-activated receptor gamma (PPARgamma), CCAAT/enhancer-binding protein alpha (C/EBPalpha), fatty acid synthase, uncoupling protein-1, and glucose transporter 4. The differentiation deficit in the KO cells could be reversed almost completely by retrovirus-mediated reexpression of IRS-1, PPARgamma, or C/EBPalpha but not the thiazolidinedione troglitazone. Phosphatidylinositol 3-kinase (PI 3-kinase) assays performed at various stages of the differentiation process revealed a strong and transient activation in IRS-1, IRS-2, and phosphotyrosine-associated PI 3-kinase in the wild-type cells, whereas the IRS-1 KO cells showed impaired phosphotyrosine-associated PI 3-kinase activation, all of which was associated with IRS-2. Akt phosphorylation was reduced in parallel with the total PI 3-kinase activity. Inhibition of PI 3-kinase with LY294002 blocked differentiation of wild-type cells. Thus, IRS-1 appears to be an important mediator of brown adipocyte maturation. Furthermore, this signaling molecule appears to exert its unique role in the differentiation process via activation of PI 3-kinase and its downstream target, Akt, and is upstream of the effects of PPARgamma and C/EBPalpha.

Adipocytes↗

Risk of aneurysm recurrence in patients with clipped cerebral aneurysms: results of long-term follow-up angiography.

BACKGROUND AND PURPOSE: With many patients living long after microsurgical aneurysm clipping for subarachnoid hemorrhage (SAH) and with the evolution of intravascular procedures as less invasive alternatives, knowledge of the long-term results of clipping is becoming important. METHODS: Of 412 patients who underwent clipping of ruptured or unruptured cerebral aneurysms at our institution between 1976 and 1994 and who survived >3 years after surgery, 225 patients who were in good general condition and younger than 80 years were offered follow-up angiography to detect newly formed aneurysms. Of the 225, 80 patients (35.6%) agreed to undergo angiography. In addition, 32 patients underwent angiography for new medical indications other than SAH. Therefore, 112 patients underwent angiography, representing a total of 140 clipped aneurysms. RESULTS: The mean interval from surgery was 9.3 years for all patients and 9.0 years for the clipped aneurysms (range 3 to 21 years). Four aneurysm regrowths were detected of the 140 (2.9%) clipped aneurysms, representing 3 of 125 completely clipped aneurysms, 1 of 14 incompletely clipped aneurysms, and 0 of 1 aneurysm not studied with postoperative angiography. De novo aneurysms were detected in 9 of 112 (8.0%) patients. The annual rate of de novo aneurysm formation was 0.89%. CONCLUSIONS: This study shows that the annual rate of de novo aneurysm formation is relatively high (0.89%) and that the cumulative risk becomes significant after 9 years. In consideration of the fatality rate of SAH, follow-up angiography may be indicated for patients with clipped aneurysms 9 to 10 years after surgery.

Angiography, Digital Subtraction↗

Radiation-induced apoptosis of oligodendrocytes in the adult rat brain.

Although radiation injuries to the brain are well documented, immediate early histological changes in the brain remain to be defined. The present study characterizes glial injury provoked in adult rat white matter within 24 h after a single irradiation of the whole brain (10 or 20 Gray). Irradiated brains were histologically and histochemically analyzed. TUNEL-positive cells exhibiting apoptotic morphology were counted in five representative regions of the white matter. Glial cell death was further evaluated by glial cell density 24 h after irradiation, which induced both dose (p < 0.0001)- and time- (p < 0.0001) dependent apoptosis in these cells. The overall apoptotic rate in the white matter peaked within 8 h after irradiation. Total glial cell density decreased significantly in the white matter 24 h after irradiation. TUNEL-positive cells were immunohistochemically negative for GFAP, a marker for astrocytes, but positive for CNP, a marker for oligodendrocytes. The apoptotic rate was highest in the external capsule (p < 0.0001), followed by the fimbria and genu of the corpus callosum (p < 0.0001). The rates were lowest in the internal capsule and cerebellum. These data indicated that brain irradiation induces rapid apoptotic depletion of the oligodendroglial population, which may participate in the development of radiation-induced pathological conditions.

Age Factors↗

Spinal tanycytic ependymoma associated with neurofibromatosis type 2--case report.

An 18-year-old girl with a 5-year history of neurofibromatosis type 2, consisting of bilateral acoustic tumors and a meningioma at the planum sphenoidale, presented with an intramedullary mass at the T-1 level, and underwent total removal of the tumor. Histological examination showed that the tumor consisted of markedly elongated spindle-shaped cells, which were immunopositive for S-100 protein and glial fibrillary acidic protein. Ultrastructural examination showed microvilli-lined lumina and prominent intercellular junctions, which were characteristic ependymal features. These findings were compatible with the diagnosis of tanycytic ependymoma. This rare subtype of ependymoma appears to arise through inactivation of NF2, in addition to some typical ependymomas.

Adolescent↗