PubMed Health⌕ Search

Biomedical subjects

K Yagi

Publications and source records attributed to K Yagi.

At least 19 recordsLinked to original sources
PubMed2007

Functional magnetic resonance imaging is more reliable than somatosensory evoked potential or mapping for the detection of the primary motor cortex in proximity to a tumor.

The accurate localization of the primary motor cortex (M1) is critical for the preservation of motor function during resection of brain tumors in and around the M1. The goal of the present study was to determine which technique provided the most accurate localization of M1. The accuracy of preoperative functional magnetic resonance imaging (fMRI), intraoperative somatosensory evoked potential (SEP) and cortical mapping for the localization of M1 was determined in 17 patients with brain tumors in and around the M1. Because localization of the M1 is typically symmetrical in the cerebral hemispheres, the M1 on the affected side was localized by determination of the M1 location on the unaffected side using fMRI with patient hand clenching. The location of M1 was successfully determined by SEP in 5 of 11 cases. In the remainder of cases, the sulcus at which phase reversal occurred during SEP was shifted 1 or 2 gyri rostral to the central sulcus. The location of M1 was successfully determined by brain mapping in 9 of 15 cases. In the remainder of cases, stimulation failed to elicit a motor response. Finally, the location of M1 was successfully determined by fMRI in 16 of 17 cases. These data indicate that fMRI was more reliable than SEP or brain mapping for the detection of M1 in proximity to a tumor.

Adult↗
PubMed2006

A leiomyoma arising from the deep palmar arterial arch.

Vascular leiomyomas, or angioleiomyomas, are benign tumours originating from smooth non-striated muscle. Leiomyomas in the hand are uncommon and their pre-operative diagnosis is difficult. We report a 65 year-old woman who developed a vascular leiomyoma arising from the deep palmar arterial arch.

Aged↗
PubMed2006

Increased intensity of acute graft-versus-host disease after reduced-intensity bone marrow transplantation compared to conventional transplantation from an HLA-matched sibling in children.

Eight children underwent reduced-intensity stem cell transplantation (RIST) from an HLA-matched sibling. They received a fludarabine-melphalan based preparative regimen. Stem cell source was bone marrow, and GVHD prophylaxis consisted of cyclosporine A alone. Acute GVHD grade II-IV and grade III-IV were observed in four (50%) and three (37.5%), respectively, out of these eight patients. This incidence was significantly higher than that after conventional bone marrow transplantation, without severe tissue damage, in the same setting of stem cell source and GVHD prophylaxis. Although the number of patients is small, our results suggest that incidence of acute GVHD after RIST for children is significant. It should be remembered that RIST for children does not seem to be an easy transplant procedure from the viewpoint of acute GVHD, although RIST is less toxic.

Adolescent↗
PubMed2006

Pattern of local relapse of maxillary sinus carcinoma.

Maxillary sinus carcinoma (MSC) is a rare disease with a variety of treatment options. The present study was undertaken to review the outcome of patients with treated MSC in order to clarify the factors related to local recurrence by analyzing CT findings. The study group comprised of 47 cases, 40 males and 7 females with a median age of 61 years (range, 40- 84 years) treated between 1988 to 1996 at the department of radiotherapy. CT was taken with a slice thickness of 5 mm and contrast material was routinely used. The mean follow-up period for the group was 45.0 months (range, 3-125 months). The treatment policy was either preoperative radiotherapy of 40Gy/16fr followed by maxillectomy or radical radiotherapy of 65Gy/26fr with partial maxillectomy during the course of radiotherapy. By using CT-simulation, wedge pair techniques were used in most patients with Cobalt or 6MV X-ray machines as treatment sources. Tumor extension was categorized into the following anatomical sites: orbital contents, other paranasal sinuses, posterior wall of the maxillary sinus, pterygoid plate/muscle, nasopharynx, infra-temporal fossa, base of the skull, anterior wall of the maxillary sinus, subcutaneous tissue, cheek mucosa, hard palate and alveolar bone. Local control was computed by using the Kaplan-Meier method and p value was measured by using Chi-squared test. The 5-year overall local control rates for all patients were 56%. The local recurrence was found in 19 of 47 patients (40.4%). Tumors extending to pterygoid plates (n=13) and pterygoid muscles (n=10) showed higher rate of local recurrences as compared to those without extensions (9/13 [69%] vs 10/34 [29%], p<0.02 and 7/10 [70%] vs 12/37 [32%], p<0.05, respectively). Extensions to nasopharynx (6/9, 66%) and base of skull (4/6, 66%) also showed higher rates of recurrence; however, those were not statistically significant. More than 80% of the relapse became manifest within 12 months of diagnosis and isolated local failure was the most common pattern. This analysis indicates that tumor extension to pterygoid plate/muscles, results in higher rates of recurrences. This may due to the difficult surgical accessibility of the tumor. During radiotherapy planning, special emphasis should be given to this sites of tumor extension to avoid possible local recurrence.

Adult↗
PubMed2005

Intraoperative cortical mapping has low sensitivity for the detection of motor function in proximity to a tumor in the primary motor area.

Six patients with brain tumors within or near the primary motor cortex underwent preoperative functional magnetic resonance imaging (fMRI) and intraoperative cortical mapping, and the accuracy of those techniques for localization of the primary motor cortex and motor function beside the tumor were determined by comparison against neuroanatomical correlates from pre-, intra- and postoperative neurological observations. The location of the primary motor cortex was detected by intraoperative cortical mapping in 5 of 6 cases and by fMRI in all 6 cases. Brain mapping provided equivocal information on the cortical representation of motor territories, and with the technique used in close proximity to the tumor, the motor territories were not detected in all but 1 case. In contrast, the areas controlling motor function in close proximity to the tumor were detected by fMRI in 4 of 6 cases. These data indicate that intraoperative cortical mapping has a low sensitivity for the detection of motor function in the area beside the tumor. Therefore, this technique may not be sufficient to prevent compromise of motor areas during tumor resection.

Aged↗
PubMed2005

Preoperative fMRI, tractography and continuous task during awake surgery for maintenance of motor function following surgical resection of metastatic tumor spread to the primary motor area.

The goal of the present study was to determine the efficacy of preoperative fMRI, tractography, and intraoperative continuous task during awake surgery in preserving postoperative motor function in patients undergoing resection of metastatic brain tumors in or near the primary motor area. Three patients with metastatic brain tumors in the primary motor area elected to undergo surgical treatment. Preoperative fMRI and tractography were performed, and various primary motor areas (e. g., hand, arm, face and leg) were identified and confirmed by cortical mapping or by the outcome of awake surgery. Cortical mapping and continuous appropriate task were performed during awake surgery. Preoperative fMRI and tractography correctly identified the primary motor area. In contrast, cortical mapping identified the gyrus of the primary motor area but was unable to identify specific primary motor areas, such as those for the hand or arm, which were compressed by the tumor. Tumor resection was terminated when any deterioration in continuous task performance was observed during awake surgery. Paresis was transient and resolved within one week in all cases. The combination of preoperative fMRI, tractography and continuous task during awake surgery helped to maintain motor function following surgical management of metastatic brain tumors of the primary motor cortex.

Brain Mapping↗
PubMed2005

Magnifying endoscopy in gastritis of the corpus.

Endoscopic diagnosis of Helicobacter pylori infection, before biopsies and serological tests are performed, is possible through careful analysis of the network of superficial vessels in patients with gastritis. At standard endoscopy, a regular arrangement of the collecting venules (RAC) is visible as numerous minute red points in the corpus of the noninfected stomach, and is not visible in H. pylori gastritis. Magnifying endoscopy provides more precise information concerning the collecting venules, the network of capillaries surrounding the gastric pits, the swelling of the surface epithelium between pits, and the enlargement and destruction of the pits. The magnified appearance is classified as Z-0 (noninfected stomach) or as Z-1 to Z-3 for successive degrees of mucosal damage in the infected stomach. Histological controls confirm the reliability of the endoscopic classification. Magnifying endoscopy also proves helpful in the assessment of completeness of eradication of H. pylori.

Gastric Mucosa↗
PubMed2005

Association of motor deficits with head position during awake surgery for resection of medial motor area brain tumors.

OBJECTIVE: Resection of tumors involving the motor area frequently results in postoperative motor deficits. In an attempt to prevent poor motor outcomes, our institution has utilized preoperative fMRI and tractography as well as intraoperative cortical mapping and continuous motor tasks during awake surgery in patients with motor area tumors. In one case, a patient demonstrated deterioration in continuous motor task performance before initiation of tumor resection. Thus, the goal of this study was to evaluate the relationship between head position and development of intraoperative or postoperative motor deficits in five patients with motor area tumors. CLINICAL PRESENTATION: In four cases, the patient's head was rotated 60 degrees from the supine position. In two cases, in which the tumor was located relatively medially, deterioration in continuous motor task function was noted prior to resection of the tumor. In the two other cases, in which the tumor was located relatively laterally, there was no deterioration of continuous motor task performance until resection of the tumor. Another patient, in whom the tumor was located relatively medially, underwent surgery with the head positioned straight and with the patient in a half-sitting position. This patient did not experience deterioration of continuous motor task performance during the surgery. CONCLUSION: These data suggest that head positioning can have a significant impact on motor function in patients with motor area tumors. Furthermore, the straight head position may be the preferred positioning, particularly for patients with tumors located on the medial side of motor area.

Aged↗
PubMed2005

A Japanese family with Alport syndrome associated with esophageal leiomyomatosis: genetic analysis of COL4A5 to COL4A6 and immunostaining for type IV collagen subtypes.

BACKGROUND: In some families, X-linked Alport syndrome (AS) is associated with diffuse leiomyomatosis. We describe clinical, pathologic and molecular-genetic findings in a Japanese family with this inheritance mode of AS in association with leiomyomatosis. PATIENT: AS was diagnosed in a one-year-old boy with recurrent aspiration pneumonia caused by esophageal stenosis from leiomyomatosis. Diagnosis was confirmed by electron microscopy coupled with type IV collagen chain subtype staining in a renal biopsy specimen. His mother, who exhibited esophageal leiomyomatosis and is heterozygous for AS, showed a discontinuous staining pattern for collagen alpha5(IV) chain along the epidermal basement membrane in a skin biopsy specimen. Genetic analysis in the boy revealed the deletion of the first two exons of COL4A6 together with deletion of the 5' end of COL4A5. Despite administration of cyclosporin A, massive proteinuria has persisted in the boy, although renal function otherwise remains normal. CONCLUSION: Identification of an AS patient during infancy is extremely rare. Clinical manifestations, including macroscopic hematuria, cataracts and leiomyomatosis caused by the large deletion involving COL4A5 to COL4A6, led to early presentation with AS.

Collagen Type IV↗
PubMed2004

Multiple cystic cavernous angiomas associated with hemorrhage.

A 29-year-old man presented with impaired mental concentration and inability to remember. Magnetic resonance and computed tomography studies revealed multiple calcified cysts. Craniotomy was performed and one of the lesions was resected. The histological diagnosis was cavernous angioma. The first report of multiple cystic cavernous angiomas is reported.

Adult↗
PubMed2004

Long-term efficacy of immunoadsorbent plasmapheresis in a patient with Budd-Chiari syndrome due to antiphospholipid syndrome: case report with nine-year follow-up.

We describe the safety and efficacy of long-term immunoadsorbent plasmapheresis (IAPP) with dextran sulfate-cellulose bead columns in antiphospholipid syndrome (APS). IAPP was administered to a 38-year old male Japanese patient with APS with Budd-Chiari syndrome (BCS), who had presented with refractory lower leg skin ulcers and arterial and venous thromboses including BCS. After hepatic vein transluminal angioplasty was performed, the combination of corticosteroid, aspirin and IAPP was administered because of an underlying bleeding tendency related to liver dysfunction. From February 1994 to February 2003, a total of 228 procedures were performed. No further thrombosis-related symptoms or bleeding have occurred for more than nine years, suggesting that IAPP with dextran sulfate cellulose columns is safe and effective for APS in preventing additional thrombotic events. This IAPP supplements anticoagulation, antiplatelet, corticosteroid and immunosuppressant therapies.

Adult↗
PubMed2003

Bone morphogenetic protein-2 enhances osterix gene expression in chondrocytes.

Osterix is a recently identified zinc-finger-containing transcription factor, which is required for skeletogenesis as no bone formation was observed in osterix-deficient mice. Osterix was first cloned as a gene whose expression was enhanced by BMP in C2C12 cells. As BMP induces ectopic bone formation in vivo via a pathway reminiscent to endochondral bone formation, BMP may also regulate osterix gene expression in chondrocytes. However, no information was available regarding the BMP actions on osterix gene expression in chondrocytes. We therefore examined the effects of BMP-2 on osterix gene expression in chondrocytes in culture. RT-PCR analysis indicated that osterix mRNA was expressed in the primary cultures of chondrocytes derived from mouse rib cartilage. The treatment with BMP-2 enhanced the levels of osterix transcripts within 24 h and the enhancement was still observed at 48 h based on RT-PCR analysis. This BMP effect was specific to this cytokine, as TGF-beta did not alter osterix gene expression. BMP effects on the osterix mRNA levels were also confirmed by Northern blot analysis. The enhancing effect of BMP on osterix gene expression was observed in a dose-dependent manner starting at 200 ng/ml. The BMP enhancement of the osterix gene expression in chondrocytes was blocked in the presence of a protein synthesis inhibitor, cycloheximide, while it was still observed in the presence of 5,6-dichloro-1-beta D-ribofuranosylbenzimidazol (DRB) suggesting the involvement of post-transcriptional events, which require new protein synthesis. These results indicated that osterix gene is expressed in the primary cultures of chondrocytes and its expression is under the control of BMP-2.

Animals↗
PubMed2003

Mixed-ligand modification of polyamidoamine dendrimers to develop an effective scaffold for maintenance of hepatocyte spheroids.

Compared with a monolayer culture, hepatocyte spheroids are known to maintain liver function for long periods. We found that hepatocytes formed spheroids when cultured on polyamidoamine dendrimers modified with fructose. Because galactose is a ligand for the asialoglycoprotein receptor on the hepatocyte cytoplasmic membrane, it was chosen as another ligand for modification in order to maintain adhesion of spheroids for long periods. Simultaneous modification of dendrimers with fructose and galactose had a marked effect on the time length of spheroid adhesion. Suppression of apoptosis and necrosis was observed in hepatocyte spheroids cultured on a dendrimer modified with fructose and galactose (F/G dendrimer). Moreover, the hepatocyte spheroids cultured on the F/G dendrimer had higher activities of liver-specific functions, such as urea synthesis and albumin gene expression, than did those cultured on single-ligand-modified dendrimers. The expression of heat shock protein (HSP) genes was examined to evaluate the stress response of cells to scaffolds. The hepatocytes cultured on the F/G dendrimer had very low expression levels of both HSP60 and HSP70 mRNAs. Thus immobilization of mixed-ligand-modified dendrimers could generate a suitable surface for hepatocyte spheroid formation. These dendrimers could be a powerful tool for generating custom-made scaffolds for cells other than hepatocytes by selecting the ligands suitable for each cell type.

Animals↗
PubMed2003

Unrelated bone marrow transplantation for Epstein-Barr virus-associated T/NK-cell lymphoproliferative disease.

Epstein-Barr virus (EBV)-associated T/NK-cell lymphoproliferative disease (LPD) has been linked to several different disorders, including chronic active EBV infection, EBV-associated hemophagocytic syndrome, hypersensitivity to mosquito bites, hydroa vacciniforme, aggressive NK-cell leukemia, and nasal/nasal-type NK-cell lymphoma. In most instances, these disorders are refractory to conventional treatments and have a poor prognosis. Here, we report a new treatment strategy for EBV-associated T/NK-cell LPD, consisting of immunochemotherapy, intensive combination chemotherapy, and stem cell transplantation. The five patients studied, two with T-cell and three with NK-cell LPD, lacked a human leukocyte antigen-matched, related donor, and therefore received bone marrow grafts from HLA-matched, unrelated donors. The preconditioning regimen consisted of total-body irradiation (12 Gy), etoposide (900 mg/m(2)), and cyclophosphamide (120 mg/kg) or melphalan (210 mg/m(2)). All patients had residual LPD by a quantitative PCR technique prior to transplantation. After unrelated bone marrow transplantation (UBMT), four of the five patients remain in continuous complete remission at a median of 19 months, without detectable EBV-DNA in peripheral blood. Thus, UBMT appears to be a reasonable option for the treatment of patients with EBV-associated T/NK-cell LPD. Detection of EBV-DNA by PCR offers an important tool for assessing minimal residual disease in patients with EBV-associated T/NK-cell LPD.

Adolescent↗
PubMed2003

Effects of novelty stress on neuroendocrine activities and running performance in thoroughbred horses.

This study investigated the effects of novelty stress on neuroendocrine activities and running performance in Thoroughbred horses. First, to examine the neuroendocrine responses to novelty stress, we exposed horses to two types of novel environmental stimuli (audiovisual or novel field stimuli). After the stimuli, plasma concentrations of vasopressin, catecholamines and adrenocorticotropin (ACTH), as well as heart rates, were significantly increased in each experiment. Second, we investigated neuroendocrine activities during incremental exercise. Plasma concentrations of vasopressin, catecholamines, ACTH and blood lactate increased as the exercise load increased. Finally, we investigated the effects of novelty stimuli on neuroendocrine activities and running performance during supra-maximal exercise (110% VHRmax). When the novelty stimuli were presented to horses, the increases in plasma vasopressin and catecholamines due to exercise load were significantly smaller than those in the control experiments. Blood lactate during supra-maximal exercise was also significantly lower and total run time until exhaustion was prolonged in the novel environmental stimuli compared to the control. These results suggest that novelty stimuli facilitate vasopressin release from the posterior pituitary in addition to activating the sympatho-adrenomedullary and the hypothalamic-pituitary-adrenocortical axes in thoroughbred horses, and increase exercise capacity, resulting in improvement of running performance during supra-maximal exercise.

Adrenocorticotropic Hormone↗