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Tetsuya Goto

Publications and source records attributed to Tetsuya Goto.

At least 19 recordsLinked to original sources
PubMed2005

Thalamic stimulation for disabling tremor in a patient with spinocerebellar degeneration.

Thalamic stimulation alleviated coarse action tremor in a patient with spinocerebellar degeneration (SCD) and led to substantial improvement in daily functioning, though disability from ataxia remained. Intraoperative microrecording revealed a significant correlation between neuronal activity of the ventral intermediate nucleus (Vim) and tremor electromyograms. The tremor-correlated activities of Vim neurons and abolition of the tremor by Vim stimulation suggest that Vim may be related to the generation of action tremor in SCD. Thalamic stimulation can be a useful treatment option for SCD patients with disabling tremor.

Aged↗
PubMed2005

Transcripts from a human primordial follicle cDNA library.

BACKGROUND: Human primordial follicles (PFs) or the oocyte-pre-granulosa complex, constitute the earliest and most immature stage of human oogenesis. The factors, signalling networks and the precise role of the oocyte and the pre-granulosa cells in initiating growth and recruitment from this finite resting pool remain largely unknown at present. METHODS: To obtain a gene resource of this oogenesis stage and thereby determine a molecular blueprint of the human PF, a cDNA library was constructed from 50 isolated human PFs using the phagemid vector pTriplEx2. RESULTS: Sequence analysis showed that 46.67% of these clones corresponded to known genes while 29.48% were uncharacterized genes that included hypothetical proteins, human cDNA clones and novel genes. Bioinformatics analysis revealed a preponderance of mitochondrial genes and repeat elements followed by ribosomal proteins, transcription and translation genes. Transcripts for heat shock proteins, cell cycle, embryogenesis genes and apoptosis genes were identified. Members of the ubiquitin-proteasome pathway, MAPK, p38/JNK, GPCR, Wnt, NF-kappaB and notch signalling pathways were identified. A mitochondrial pathway and a transcription factor pathway in the human PF were generated. The gene networks in the transcription factor pathway provided a first glimpse of the balance between proliferation and cell death/apoptosis in this earliest stage of oogenesis. CONCLUSIONS: The abundance and diversity of retroviral elements and transcriptional repressor genes in the human PF suggest these could contribute to the maintainance of this oogenesis stage. The role of these genes in initial recruitment and in subsequent oogenesis stages will be greatly facilitated and elucidated by printing a human PF cDNA array of the sequenced clones and using it for gene profiling.

Cell Differentiation↗
PubMed2005

Neuropeptide substance P stimulates the formation of osteoclasts via synovial fibroblastic cells.

The present study was designed to evaluate the effects of neuropeptide substance P (SP) on the formation of osteoclasts via synovial fibroblastic cells. Synovial fibroblastic cells derived from rat knee joint expressed the SP receptor, neurokinin-1 receptor (NK(1)-R). The addition of SP stimulated the proliferation of synovial fibroblastic cells and this effect was inhibited by SP or NK(1)-R antagonists. Increased expression of the receptor activator of nuclear factor kappaB ligand (RANKL) in synovial fibroblastic cells after the addition of SP was demonstrated by reverse transcriptase-polymerase chain reaction and immunofluorescence staining. Osteoprotegerin expression in synovial fibroblastic cells was decreased after incubation with SP. In co-cultures of synovial fibroblastic cells and rat peripheral blood monocytes, SP stimulated osteoclastogenesis. These results suggest that SP in the joint cavity may cause both hypertrophy of the synovium and induction of increased osteoclast formation through the increased expression of RANKL in the synovium.

Animals↗
PubMed2005

The bisphosphonate pamidronate on the surface of titanium stimulates bone formation around tibial implants in rats.

Many materials with differing surfaces have been developed for clinical implant therapy in dentistry and orthopedics. We analyzed the quantity of new bone formed in vivo around calcium-immobilized titanium implants with surfaces modified using pamidronate (PAM), a nitrogen-containing bisphosphonate (N-BP), implants of pure titanium, and titanium implants immobilized with calcium ions. New bone formation was visualized using fluorescent labeling (calcein blue and alizarin complexone) with intravenous injection at 1 and 3 weeks after implantation. After 4 weeks, undecalcified sections were prepared, and new bone formation around the implants was examined by morphometry using confocal laser scanning microscopy images. After 1 week, more new bone formed around the PAM-immobilized implant than around the calcium-immobilized and pure titanium implants. This was also seen with the new bone formation after 3 weeks. After 4 weeks, significantly more new bones were formed around the BP-immobilized implant than around the calcium ion-implanted and pure titanium implants. The new N-BP-modified titanium surface stimulates new bone formation around the implant, which might contribute to the success of implant therapy.

Animals↗
PubMed2005

Changes in the distribution of laminin-5 during peri-implant epithelium formation after immediate titanium implantation in rats.

Laminin-5 (Ln-5), a component of the basement membrane (BM), regulates epithelial cell migration and adhesion. This study used anti-Ln-5 (gamma2chain) antibody to investigate the distribution of Ln-5 during the formation of peri-implant epithelium (PIE) in rats, and compared it to the distribution of Ln-5 during oral mucosa formation after tooth extraction. One day after extraction, the junctional epithelium (JE) had disappeared. After 3 days, new epithelium formed from the oral sulcular epithelium (OSE) and extended horizontally over the wound with Ln-5-positive cells at the leading edge. After 5 days, the epithelium extending from the OSE on each side of the wound joined and formed additional new epithelium. The new epithelium expressed Ln-5 in the BM. After 1-2 weeks, the oral epithelium (OE) extending from the sides of the wound joined in the center. Thereafter, OSE and new epithelium disappeared, and only OE remained covering the wound. Three days after implantation (titanium), no JE remained. New epithelium formed from the keratinized OSE extending apically with Ln-5-positive cells. After 1-2 weeks, the new epithelium became the PIE and spread further apically facing the implant surface. Ln-5 was expressed at the PIE-connective tissue interface, but not at the implant-PIE interface. Finally, after 4 weeks, Ln-5 was expressed at the implant-PIE interface, and the PIE was non-keratinized epithelium. These findings suggest that Ln-5 induces cell migration during PIE formation, and that PIE originates from OSE. Furthermore, they support the hypothesis that Ln-5 contributes to the attachment of PIE to titanium, regardless of the delay in the synthesis and deposition of Ln-5 at the titanium-PIE interface.

Animals↗
PubMed2005

Ultrastructural localization of laminin-5 (gamma2 chain) in the rat peri-implant oral mucosa around a titanium-dental implant by immuno-electron microscopy.

Laminin-5 (Ln-5) is an important molecule associated with epithelial cell adhesion and migration. In the gingiva around the tooth, Ln-5 localizes within basement membranes between the junctional epithelium (JE) and the tooth or connective tissue. Recently, we reported that in the oral mucosa around a dental implant, Ln-5 is expressed within the basement membranes at the implant-peri-implant epithelium (PIE) interface, and at the PIE-connective tissue interface. However, the ultrastructural localization of Ln-5 within or along the PIE has not yet been reported. Therefore, peri-implant oral mucosa was treated with anti-Ln-5 (gamma2 chain) antibody and examined using immuno-electron microscopy. Ln-5 was localized in the cells of the innermost-third layer and basal layer of the PIE. A 100-nm-wide Ln-5-positive internal basal lamina (basement membrane) and hemidesmosomes as adhesion structures were formed at the apical portion of the implant-PIE interface. However, at the upper-middle portion of the interface, these adhesion structures were not observed. Furthermore, at the PIE-connective tissue interface, the Ln-5-positive external basal lamina (basement membrane) and hemidesmosomes were partially deficient. Judging from these findings, we concluded that Ln-5 contributes to the attachment of the PIE to the titanium surface, and that PIE attached to titanium at the apical portion of the dental implant-PIE interface.

Animals↗
PubMed2005

Perinatal outcome of blastocyst transfer with vitrification using cryoloop: a 4-year follow-up study.

OBJECTIVE: To evaluate perinatal outcome of ultrarapid vitrified blastocyst transfer. DESIGN: Retrospective study. SETTING: Private IVF clinics. PATIENT(S): One hundred eight women, who delivered 147 babies. INTERVENTION(S): Supernumerary blastocysts were vitrified using cryoloop method and transferred after warming. MAIN OUTCOME MEASURE(S): Survival rate of blastocyst after vitrification, implantation and pregnancy rates, neonatal outcome and congenital birth defects. RESULT(S): A total of 1,129 vitrified blastocysts from 435 cycles were warmed and 967 survived (85.7%). In 413 cycles of transfer, the pregnancy, implantation, and abortion rates were 44.1%, 29.0%, and 22.0%, respectively. Of 108 deliveries, 34 (32.9%) were multiple pregnancies and 20 were preterm (18.5%). Out of 147 children born, 50.3% were male and congenital birth defects were observed in 1.4%. These results were similar with those of fresh blastocyst transfer program. CONCLUSION(S): The vitrification of blastocyst using cryoloop is a simple, easy, and quick method. This technique yields the same high pregnancy and implantation rates as fresh blastocyst transfer. Congenital defect rate in this study was similar to fresh blastocyst transfer, proving the method to be safe.

Adult↗
PubMed2004

Gross total surgical removal of malignant glioma from the medulla oblongata: report of two adult cases with reference to surgical anatomy.

Surgery was performed on the medulla oblongata of two adult patients with malignant glioma. Gross total resection of the tumors, located laterally or medially in the upper half of the medulla respectively, was achieved. The patient with the medially located tumor experienced significant postoperative neurological deterioration including sleep apnea. The other patient with the laterally located tumor showed symptomatic improvement without respiratory complications. The patient with an anaplastic astrocytoma survived approximately 4 years and the patient with a glioblastoma multiforme approximately 2 years. Although the upper half of the medulla is more critical than the lower half, a lateral approach to the upper half of the medulla appears to be relatively safer than a medial approach. Some cases of focal malignant gliomas in the medulla may be amenable to gross total resection in order to achieve improved outcome. Surgery can be undertaken when a tumor is unilateral and its margin appears relatively clear on magnetic resonance images.

Adult↗
PubMed2004

Surgical experience with resection en bloc of intramedullary astrocytomas and ependymomas in the cervical and cervicothoracic region.

We performed 8 operations on 7 patients with benign intramedullary astrocytomas and ependymomas in the cervical and cervicothoracic region. All patients initially underwent gross total tumor resection en bloc. One patient with an astrocytoma showed tumor recurrence postoperatively, and underwent a second operation resulting in subtotal removal. The follow-up after the initial surgery ranged from 2.7 to 19.7 years (mean 8.5 years). Symptomatic improvement was observed in 6 patients after the initial operation. Two patients showed postoperative neurological deterioration, one with an ependymoma and the other after the second operation. No operative complications or deaths, nor postoperative respiratory dysfunction occurred. Benign intramedullary astrocytomas and ependymomas of the cervical and cervicothoracic spinal cord can be treated by radical resection en bloc with a low morbidity and recurrence, as well as acceptable outcomes. We describe here the surgical technique for en bloc tumor removal.

Adolescent↗
PubMed2004

GnRH antagonist improved blastocyst quality and pregnancy outcome after multiple failures of IVF/ICSI-ET with a GnRH agonist protocol.

BACKGROUND: To determine the efficacy of a gonadotrophin-releasing hormone (GnRH) antagonist, cetrorelix, in improving the quality of embryos and pregnancy outcome, we performed a study in patients with a history of multiple failures of in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) cycles with a GnRH agonist (GnRHa) long protocol. METHODS: Forty women with no live births after conventional IVF or ICSI embryo transfer (ET) and subsequent blastocyst transfer (BT) with a GnRHa long protocol entered this study. The treatment protocol consisted of a daily dose of clomiphene citrate 100 mg for 5 days and gonadotrophin injections daily from cycle day 4 onward. Cetrorelix, 0.25 mg/day, was started when the leading follicle reached 14 mm. Induction of ovulation was triggered with human chorionic gonadotrophin (HCG) (N = 36) or GnRHa (N = 4). It was possible to perform BT in 38 patients. RESULTS: Comparison of the results with the results for BT with the previous GnRHa protocol showed no significant differences in number of oocytes retrieved or the zygote- and blastocyst-development rate. With the cetrorelix protocol, however, number of patients whose embryos had developed to at least one expanded blastocyst on day 5 was significantly higher than with the GnRHa protocol (25 vs. 9) (p < 0.001), and 16 of the women became pregnant (42.1%), with 7 delivering 9 infants, 4 ending in abortion (25%), and 5 in progressing. CONCLUSIONS: The use of a GnRH antagonist in controlled ovarian hyperstimulation improves the outcome of pregnancy of patients with a history of multiple failure of IVF/ICSI-ET in a GnRHa protocol, most likely due to improvement of the quality of the blastocysts generated.

Adult↗
PubMed2004

Functional role of the Na+/H+ exchanger in the regulation of cerebral arteriolar tone in rats.

OBJECT: In vascular smooth-muscle cells, the Na+/H+ exchanger (NHE) is involved in the regulation of [Na+]i, pHi through [H+], and cell volume. Recently, investigations have determined that this exchanger contributes to ischemia and reperfusion injury in coronary circulation. Nonetheless, there is limited information on this glycoprotein in cerebral circulation, especially microcirculation. Thus, the authors in the present study examined the role of NHE in the regulation of cerebral arteriolar tone and its related mechanisms in vitro. METHODS: The internal diameter of isolated pressurized intracerebral arterioles in rats was monitored with the aid of a microscope. To examine the basal activity of NHE two kinds of Na+/H+ exchange inhibitors (FR183998 and 5-[N,N-hexamethylene]amiloride) were administered in the arterioles. Furthermore the authors studied the effects of nitric oxide (NO) synthase inhibitor (NG methyl-L-arginine), Na+/K+ -adenosine triphosphatase (NKA) inhibitor (ouabain), and the Na+/Ca++ exchange inhibitor (SEA0400) on the vascular response induced by either of the Na+/H+ exchange inhibitors. Both of the Na+/H+ exchange inhibitors constricted the arteriole. Subsequent application of NO synthase inhibitor further decreased the diameter of the arterioles. The Na+/H+ exchange inhibitor-induced constriction was completely abolished in the presence of ouabain and SEA0400. CONCLUSIONS: The NHE is active in the basal condition and regulates cerebral arteriolar tone through NKA and the Na+/Ca++ exchanger. Endogenous NO is not related to the activity of NHE in basal conditions.

Amiloride↗
PubMed2004

The initial attachment and subsequent behavior of osteoblastic cells and oral epithelial cells on titanium.

The interaction between implant materials and bone cells or oral epithelial (OE) cells contributes to the clinical success of dental implants. The functional activity of cells in contact with an implant is determined by its surface properties. Before cells attach, extracellular matrix (ECM) in the serum deposits on the substrate; rounded cells then attach and spread upon it. Cells form focal adhesions and polarize, then start to migrate or proliferate to form colonies. Comparison of the attachment and behavior of osteoblastic cells on titanium (Ti) and hydroxyapatite (HA) revealed that more cells attached on HA and that these spread more rapidly than on Ti. In contrast, cells did not form good stress fibers or vinculin-positive focal adhesions on HA, whereas the cells on Ti possessed well-defined and polarized stress fibers. The initial attachment of OE cells to Ti was inferior to that on polystyrene culture dish or glass, and the OE cell migration area, indicated by the deposition of LN5, was smaller on Ti than on the other materials. This review summarizes data on the attachment and behavior of osteoblastic cells and OE cells on biomaterials, which may suggest future improvements in surface properties.

Animals↗
PubMed2003

In vitro assay of mineralized-tissue formation on titanium using fluorescent staining with calcein blue.

Many studies have examined mineralized-tissue formation on titanium in vivo and in vitro; however, no precise method for measuring the mineralized tissue produced by cultured osteoblastic cells on titanium in vitro has been established. This study developed a method for measuring mineralized-tissue formation by cultured rat osteoblastic cells on titanium in vitro, and re-evaluated the effects of modifying the titanium surface. We used calcein blue, which binds to mineralized tissue, and measured the resulting fluorescence under ultraviolet light. A 1-h incubation with 3.1x10(-3)M calcein blue resulted in sufficient fluorescence of bone-like nodules on the titanium. Consequently, we found that osteoblastic cells produced larger bone-like nodules on titanium than in culture dishes. Fewer bone-like nodules formed on calcium-ion impregnated titanium than on pure titanium. However, when bisphosphonate was immobilized on the calcium-ion impregnated titanium, more bone-like nodules formed than on pure titanium. The results suggest that bisphosphonate immobilization on titanium is useful for stimulating mineralized-tissue formation on titanium implants.

Animals↗
PubMed2003

Repeat operations in the management of clival chordomas: palliative surgery.

Some chordomas have a very poor prognosis because of their aggressive growth nature, but the efficacy of repeat operations for these cases has not been well documented. This report concerns 3 patients with aggressive chordoma of the clivus, who underwent operations 6 to 12 times over a period of 8 to 17 years because of symptomatic regrowth. Overall mean interval between repeat operations was 18 months with a range from 5 to 57 months and survival times were 9 to19 years after the first surgery. Main symptoms before each operation were diplopia and visual disturbance. Repeat palliative operations by intentional extradural debulking of the tumour to decompress offending neural structures, as well as maximal removal of the tumour, using appropriate skull base approaches, can mitigate progressive symptoms, and may result in better quality and some prolongation of life, although our patients gradually deteriorated neurologically throughout the clinical course.

Chordoma↗
PubMed2003

Cathepsins in the osteoclast.

The mechanism by which bone collagen and other organic components are degraded by the osteoclast during osteoclastic bone resorption was unclear until the 1980s. Studies conducted since the early 1990s have identified lysosomal proteases, mainly cathepsins that are active at low pH, involved in osteoclastic bone resorption. Several cathepsins, such as cathepsins C, D, B, E, G and L, were initially demonstrated to take part in the degradation of organic bone matrix in osteoclasts. Cathepsin K, which has high proteolytic activity and localizes primarily in osteoclasts, was discovered in 1995. This first tissue-specific cathepsin was associated with pycnodysostosis, a genetic disorder observable as an osteopetrotic phenotype in cathepsin K-deficient mice. Cystatin C, an endogenous inhibitor of cysteine proteases, regulates the activity of cathepsin K. However, detailed morphological observations suggest that the organic bone matrix is degraded by not only cathepsin K, but also by matrix metalloproteinases or other cathepsins. The osteoclast possesses a unique endocytotic/exocytotic structure and each cathepsin is specifically localized in the osteoclast, which implies that each cathepsin contributes cooperatively to the process of osteoclastic bone resorption. Further studies may clarify the regulation of cathepsin activities and the roles of cathepsins during bone remodelling.

Animals↗
PubMed2003

Feasibility of using the potassium titanyl phosphate laser with micromanipulators in robotic neurosurgery: a preliminary study in the rat.

OBJECT: Robotic surgery can be used as a novel technology in ultramicrosurgery. A microscopic-manipulator (micromanipulator) system, which has a rigid neuroendoscope and three guiding manipulators, was developed in Japan for less invasive telerobotic neurosurgery. To apply this system in a clinical setting, it is necessary to confirm that it is capable of performing various surgical procedures including cutting, coagulation, and bleeding control. The authors chose the potassium titanyl phosphate (KTP) laser for such procedures. The aim of this paper was to evaluate the feasibility of this system mounted with the KTP laser. METHODS: A prototypical micromanipulator system was tested in rats. Two kinds of in vivo experiments were performed using the KTP laser: coagulation and biopsy. The coagulated lesions were precisely aligned and their maximum depths were proportional to the energy applied during the coagulation experiment. The diagnosable specimens were obtained during the biopsy experiment. The micromanipulator system was able to perform all surgical procedures accurately. There was no complication relating to the use of the micromanipulator system such as brain injury or uncontrollable bleeding. CONCLUSIONS: The results from this study proved that this system works precisely and safely and will become a new neurosurgical tool in managing lesions that are difficult to treat using conventional microsurgery or neuroendoscopic surgery.

Animals↗