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Yuichi Yamashita

Publications and source records attributed to Yuichi Yamashita.

18 recordsLinked to original sources
PubMed2006

Long-term graft outcome of pediatric liver transplantation in Copenhagen: analysis of the first 51 cases.

BACKGROUND: Graft loss after liver transplantation remains a significant problem, especially in pediatric patients. The aim of this study was to assess our initial series of pediatric liver transplantation and to identify the risk factors that influence graft outcome. METHODS: The first 51 transplantations were analyzed retrospectively. All transplantations were stratified into three groups according to graft type (full-size, reduced-size, and living-related-donor graft). Survival data of the grafts were stratified and multivariate analysis conducted with respect to preoperative and surgical factors. RESULTS: Seventeen of all the transplants were full-size grafts and 34 technical-variant grafts (27 reduced-size grafts from cadavers and 7 living-related-donor grafts). The overall graft survival rates were 65, 62 and 53% at 1, 3 and 5 years, respectively. Twenty-three of 51 grafts (45%) were lost. Poor status of the recipients (hospitalization or intensive care unit care before surgery), a retransplanted graft, and a reduced-size graft were independent risk factors for graft failure. With experience, overall graft survival has improved significantly and the differences in graft survival between graft types have disappeared. CONCLUSIONS: To improve graft survival after pediatric liver transplantation, the timely referral of potential recipients to the transplant team and employing a meticulous technique during the operation, particularly for the technical-variant graft, are required.

Adolescent↗
PubMed2006

A survey of the timing and approach to the surgical management of patients with acute cholecystitis in Japanese hospitals.

BACKGROUND/PURPOSE: Despite the fact that there is evidence advocating early laparoscopic cholecystectomy for acute cholecystitis (AC), the practice of this treatment has not been investigated sufficiently. This study was designed to assess the current practice of laparoscopic cholecystectomy for AC among Japanese general surgeons. METHODS: A postal questionnaire was sent to the 291 councillors of the Japanese Society of Abdominal Emergency Medicine in order to ascertain their current management of patients with AC. RESULTS: The response rate was 72.5%. A policy of early cholecystectomy for AC was adopted by 41.7% of the responding surgeons. However, almost the same percentage of surgeons routinely managed their patients conservatively, and opted for delayed cholecystectomy at a later date. The adoption of laparoscopic cholecystectomy was made by 79.1% of surgeons. Laparoscopic cholecystectomy for patients with AC who had percutaneous transhepatic gallbladder drainage (PTGBD) was adopted by 73.9% of the surgeons. Of the surgeons opting for laparoscopic cholecystectomy, 37.3% performed intraoperative cholangiography laparoscopically for all patients with AC. CONCLUSIONS: Although early cholecystectomy for patients with AC was not adopted by the majority of the surgeons who responded, laparoscopic cholecystectomy was a common procedure for early and delayed cholecystectomy. Despite evidence that strongly supports the use of early cholecystectomy, the use of this treatment remains suboptimal in Japan.

Acute Disease↗
PubMed2006

[A case of recurrent gastric cancer with dihydropyrimidine dehydrogenase (DPD) deficiency].

Dihydropyrimidine dehydrogenase (DPD) is a reducing enzyme for fluoropyrimidine which is a widely-used anti-cancer agent, and its deficiency leads to serious toxicities. We report a rare patient with a DPD deficiency. A 39-year-old man was suspected to have a gastric cancer recurrence from the elevation of CEA. Although TS-1 was administered for five days, it was stopped due to the development of grade 2 anorexia and nausea. Although we administered UFT at his request after a one-month drug rest, grade 1 stomatorrhagia besides the former adverse events developed after five days. Therefore he discontinued it and was admitted to our hospital. After 19 days, he died from multiple brain hemorrhage despite the intensive therapies. We considered that the congenital DPD deficiency caused the development of these adverse events because the DPD value was less than 5 pmol/mg/min in mononuclear cells of peripheral blood.

Adult↗
PubMed2005

Successful resection of an infected duodenal duplication cyst after percutaneous cyst drainage: report of a case.

We report a case of a duodenal duplication cyst complicated by infection. An 8-year-old boy was brought to our hospital with severe abdominal pain and a fever of 39.8 degrees C. He had a 5-year history of occasional abdominal pain with vomiting. On examination, a cystic mass was felt under the liver. We performed percutaneous drainage of the cyst under a suspected diagnosis of a choledochal cyst complicated by acute biliary infection. A contrast study through the drainage tube and surgical exploration revealed a duodenal duplication cyst communicating with the second part of the duodenum. The patient had an uneventful recovery and remains well 5 years after surgery. To the best of our knowledge, this is the first documented case of an infected duodenal duplication cyst successfully treated by resection after percutaneous drainage.

Child↗
PubMed2005

Vitamin A up-regulates the expression of thrombospondin-1 and pigment epithelium-derived factor in retinal pigment epithelial cells.

Vitamin A is essential for the visual system. It is metabolized in the retina and the resulting product, retinoic acid (RA), greatly affects the structure and functions of retinal pigment epithelial (RPE) cells. RPE cells produce a variety of extracellular matrix (ECM) proteins and angiogenic factors, both of which are expressed at varying levels in the normal RPE layer. In this study, we investigated the effect of all-trans-retinoic acid on the production of an ECM protein, thrombospondin-1 (TSP-1), and two angiogenic factors, pigment epithelium-derived factor (PEDF) and vascular endothelial growth factor (VEGF) by RPE cells. RA increased the release of TSP-1 and PEDF, but not that of VEGF, from human RPE cells in vitro. In vitamin A-deficient mice, the expression of TSP-1 and PEDF in the RPE layer considerably decreased compared with that of normal control mice. The vitamin A deficiency hardly affected the accumulation of VEGF in the RPE layer. These findings suggest that vitamin A modulates the structure and anti-angiogenic functions of the RPE layer partly by up-regulating the expression of the angiogenesis-related ECM protein, TSP-1, and the anti-angiogenic factor, PEDF.

Animals↗
PubMed2004

Endoscopic extraction of a peritoneal loose body: a case report of an infant.

A 2-month-old female infant with a peritoneal loose body presenting as an abdominal mass and urinary tract infection is described. Peritoneal loose bodies are usually found in the pelvis of adult patients. A peritoneal loose body should be considered in the differential diagnosis of a mobile lesion found in the abdomen.

Calcinosis↗
PubMed2004

Generation, immunologic characterization and antitumor effects of human monoclonal antibodies for carcinoembryonic antigen.

We generated fully human mAbs (HmAbs) to carcinoembryonic antigen (CEA) using the KM mouse, which carries a human chromosome 14 fragment containing the entire Ig H chain loci and human kappa L chain segments in the mouse genome. Forty-six hybridoma clones producing HmAbs to CEA were thus obtained by fusing the P3-U1 mouse myeloma cells with splenocytes of the KM mice immunized with CEA. Among them, 22 clones produced HmAbs that reacted with CEA but not with 3 other CEA-related cell adhesion molecule (CEACAM) family members, CEACAM1, CEACAM6 and CEACAM8. In 12 HmAbs examined, 8 were IgG4, 2 were IgG3, 1 was IgG2, and the other was IgG1. The affinity constants for CEA of these HmAbs were comparable to those of the previously prepared mouse anti-CEA mAbs (MmAbs). BIAcore analyses revealed that 1 and 2 of the 22 HmAbs react with 2 epitopes defined by MmAbs on the domain N and the domain A1 or B1 of CEA, respectively. In the presence of human complement in vitro, 2 HmAbs tested showed substantial cytotoxicity, namely, 50-65%, against CEA-expressing tumor cells. With human lymphokine-activated killer cells in vitro, 3 HmAbs tested exhibited 40-65% Ab-dependent cell-mediated cytotoxicity against the tumor cells. Moreover, one of the HmAbs induced a significant inhibition of tumor growth when administered to mice xenografted with the CEA-expressing cells. Considering their lack of immunogenicity to humans, these CEA-specific HmAbs may be useful for immunotherapeutic approaches as well as for immunodiagnosis.

Animals↗
PubMed2004

Risk for K-ras gene mutations in smoking-induced lung cancer is associated with cytochrome P4501A1 and glutathione S-transferase micro1 polymorphisms.

Polycyclic aromatic hydrocarbons (PAHs) and other tobacco-related carcinogens are oxidized by phase I enzymes into reactive metabolites that are then detoxified by phase II enzymes. These findings suggested that polymorphisms in genes controlling metabolism of carcinogens underlie individual variations in cancer susceptibility. Moreover, it is unclear whether there is a relation between genetically determined individual susceptibilities and target gene mutations in lung carcinogenesis. We examined K-ras mutations in relation to polymorphisms in the cytochrome P4501A1 (CYP1A1) and glutathione S-transferase micro1 (GSTM1) genes in 246 patients with lung adenocarcinoma and 167 patients with lung squamous cell carcinoma. K-ras mutations were found in 33 of 413 (8.0%) tumors, and all K-ras gene mutations were found in habitual smokers, 110 non-smokers were excluded from final analysis. Among smokers with lung adenocarcinoma, K-ras mutations occurred with greater frequency in patients with the GSTM1(-) genotype than in those with the GSTM1(+) genotype. Patients with a combination of the CYP1A1 m1/m2 and GSTM1(-) genotypes showed an increased probability of having mutated K-ras genes (OR, 6.00; p=0.031; 95% CI, 1.18-30.62) in comparison to those with the CYP1A1 m1/m1 and GSTM1(+) genotypes. The impact of combined genotypes of the CYP1A1 Ile/Val polymorphism and GSTM1 on mutation of K-ras was also analyzed, and a higher risk of having a mutated K-ras gene was found for both the CYP1A1 Ile/Ile and GSTM1(-) (OR, 6.32; p=0.021; 95% CI, 1.33-30.19) and CYP1A1 Ile/Val and GSTM1(-) (OR, 6.09; p=0.042; 95% CI, 1.07-34.72) genotype combinations in patients with adenocarcinoma. There was no significant association for squamous cell carcinoma. In conclusion, these findings suggest that K-ras mutations in smokers with lung adenocarcinoma may be due in part to accumulation of carcinogens, which is not adequately detoxified in individuals with certain CYP1A1 genotypes and the GSTM1(-) genotype.

Adenocarcinoma↗
PubMed2003

Virtual endoscopic images by 3D FASE cisternography for neurovascular compression.

Three-dimensional fast asymmetric spin echo (3D FASE) cisternography provides high spatial resolution and excellent contrast as a water image acquisition technique. It is also useful for the evaluation of various anatomical regions. This study investigated the usefulness and limitations of virtual endoscopic images obtained by 3D FASE MR cisternography in the preoperative evaluation of patients with neurovascular compression. The study included 12 patients with neurovascular compression: 10 with hemifacial spasm and two with trigeminal neuralgia. The diagnosis was surgically confirmed in all patients. The virtual endoscopic images obtained were judged to be of acceptable quality for interpretation in all cases. The areas of compression identified in preoperative diagnosis with virtual endoscopic images showed good agreement with those observed from surgery, except in one case in which the common trunk of the anterior inferior cerebellar artery and posterior inferior cerebellar artery (AICA-PICA) bifurcated near the root exit zone of the facial nerve. The veins are displayed in some cases but not in others. The main advantage of generating virtual endoscopic images is that such images can be used for surgical simulation, allowing the neurosurgeon to perform surgical procedures with greater confidence.

Adult↗
PubMed2003

Optical topography: practical problems and new applications.

We will briefly review the present status of optical topography and then discuss the method of improving practicality, i.e., the signal-to-noise (S/N) ratio and the spatial resolution in observations of higher-order brain functions. The optimum wavelength pair improved the S/N ratio sixfold for deoxyhemoglobin, and new configurations of light irradiation and detection positions doubled the spatial resolution. We also report on developing application fields of optical topography. This modality will bridge the gap between natural sciences, neuroscience, and pedagogy, and show actual real-time brain activity.

Brain↗
PubMed2002

Thrombospondin-1 differentially regulates release of IL-6 and IL-10 by human monocytic cell line U937.

We investigated possible regulatory effects of thrombospondin-1 (TSP-1), a multifunctional extracellular matrix protein, on cytokine release from macrophages. Immobilized TSP-1 enhanced IL-6 release from the human monocytic U937 cells stimulated with phorbol myristate acetate and LPS, whereas it inhibited IL-10 release. The 70-kDa fragment of TSP-1 containing the type 1 repeats showed the same regulatory effects. The enhanced IL-6 release by TSP-1 was inhibited by anti-CD36 antibody or antibody against the sequence of the binding site to CD36 in the type 1 repeats of TSP-1. Conversely, the decrease in IL-10 release by TSP-1 was strengthened by the blocking of the interaction between CD36 and TSP-1. Furthermore, the involvement of TGF-beta1 in the inhibition of IL-10 release by TSP-1 was indicated by the facts that (i) TSP-1 induced activation of TGF-beta1 produced by the U937 cells, (ii) exogenously added TGF-beta1 inhibited IL-10 release, and (iii) antibody against TGF-beta1 blocked the inhibition of IL-10 release by TSP-1. Together, the present findings suggest that TSP-1 enhances IL-6 release from macrophages by interaction with CD36, whereas IL-10 release is regulated by the balance between the enhancing effect of TSP-1 via CD36 and the suppressive effect by TSP-1-activated TGF-beta1.

Adjuvants, Immunologic↗
PubMed2002

Simultaneous recording of event-related auditory oddball response using transcranial near infrared optical topography and surface EEG.

Near infrared optical topography (OT) is the measurement of hemoglobin absorption simultaneously from an array of optical fibers on the scalp to construct maps of cortical activity. We demonstrate that OT can be used to simultaneously detect and characterize the hemodynamic responses associated with an "oddball" auditory stimulus and that corresponding electrical event related potentials can be acquired simultaneously using conventional scalp recordings. In addition to the measured electrical response, the hemodynamic localization is consistent with fMRI studies, which show significant activation in the temporal and parietal cortical regions. The event-related response of total hemoglobin showed relatively slow peak latencies (5.8 +/- 0.3 s), which were also consistent with fMRI. The current study shows the regions of peak hemodynamic activity that are in closest proximity to areas of peak electrical activity. This is the first demonstration of simultaneous ERP electrical recording and non-invasive optical mapping in human subjects, which promises to be an important tool in the characterization of both normal and abnormal brain function.

Auditory Cortex↗
PubMed2002

Opposite effects of thrombospondin-1 via CD36 and CD47 on homotypic aggregation of monocytic cells.

Thrombospondin-1 (TSP-1), an extracellular matrix protein, has a multimodular structure and each domain specifies a distinct biological function through interaction with a specific ligand. In this study we found that exogenously added TSP-1 inhibits phorbol myristate acetate (PMA)/LPS-induced homotypic aggregation of human monocytic U937 cells, whereas the 70-kDa fragment of TSP-1 generated by the proteolytic cleavage of the intact molecule promotes the homotypic aggregation. The aggregation was also inhibited by anti-CD47 mAb or the 4N1K peptide, of which sequence is derived from the CD47-binding site of TSP-1 and absent in the 70-kDa fragment. In contrast, the augmented cell aggregation by the 70-kDa fragment was hampered by anti-CD36 mAb or antibody against the CD36-binding site of TSP-1. The cell aggregation of U937 cells was completely blocked, even in the presence of the 70-kDa fragment, by mAb against leukocyte function associated antigen-1 (LFA-1) or intercellular adhesion molecule-1 (ICAM-1). We therefore propose that TSP-1 may regulate LFA-1/ICAM-1-mediated cell adhesion of monocytes/macrophages by either the inhibitory effect through CD47 or the promoting effect through CD36 depending on which domain/fragment is functional in a given biological setting.

Antigens, CD↗
PubMed1999

Analysis of immunoglobulin light-chain mRNA in gastric malignant lymphoma using new highly sensitive in situ hybridization method.

BACKGROUND: To analyze B-cell monoclonality, we need fresh materials for the Southern blotting method. In situ hybridization (ISH) for the detection of immunoglobulin light-chain mRNA can be used in formalin-fixed and paraffin-embedded tissues. However, it is difficult to detect low levels of mRNA copies. So we must develop new highly sensitive in situ hybridization methods to diagnose gastric malignant lymphoma.METHODS: We analyzed materials from 15 patients with gastric malignant lymphoma, using a new highly sensitive ISH method, and compared the results with those of a conventional method.RESULTS: With this new method, 13 of 15 cases were shown to have monotypic cytoplasmic signals, and monoclonality was detected in 3 of 4 cases of mucosa-associated lymphoid tissue (MALT) lymphoma.CONCLUSIONS: The accuracy of endoscopic biopsies is not satisfactory. However, the detection of immunoglobulin light chain mRNA, using the new highly sensitive ISH method with a non-radioactive isotope oligonucleotide probe, can be used to diagnose gastric malignant lymphoma even when conventional immunoglobulin light-chain mRNA or proteins alone cannot demonstrate the clonality.

Journal Article↗
PubMedDate not supplied

Surgical treatment for elderly breast cancer patients over the age of 70.

Because elderly breast cancer patients differ in various biological characteristics from younger patients, it is important to clarify the clinical characteristics and treatment results of elderly patients with this disease. A total of 332 breast cancer cases (327 patients) who received surgery were divided into three groups, consisting of a premenopause group younger than 50 years of age (group A, N = 144), a postmenopause group younger than 70 years of age (group B, N = 140), and elderly cases 70 years of age or older (group C, N = 48). A positive node involvement was seen in about 40% of all cases, but the lymph node positivity of group C was significantly lower than that of group A or B. The postoperative 5-year survival rates of groups A, B, and C were 88.9%, 87.5%, and 89.4% at all stages, and 90.2%, 86.2%, and 91.4% at stages I and II, respectively. Only in group C did survival rates show no significant difference between node status. We conclude that both radical and cosmetic surgical treatments performed in elderly breast cancer patients aged 70 years or older are as effective as in younger breast cancer patients.

Adult↗
PubMedDate not supplied

Left-sided gallbladder associated with congenital hypoplasia of the left lobe of the liver: a case report and review of literature.

Left-sided gallbladder is a rare anomaly that is often associated with other abnormal anatomy in the hepatobiliary system. We report our experience of a case of left-sided gallbladder associated with the congenital hypoplasia of the left lobe of the liver. A 71-year-old woman underwent cholecystectomy for acute cholecystitis. Intraoperative findings revealed the absence of the left lobe of the liver. The gallbladder was located in the left side of the round ligament, which was associated with abnormal intrahepatic portal branching. The incidence of left-sided gallbladder without situs inversus is very rare. The following anomalous anatomy associated with left-sided gallbladder should be a concern when a surgeon encounters a left-sided gallbladder: right-sided round ligament associated with abnormal intrahepatic portal branching and ectopic gallbladder attached to the left lobe of the liver that connects to the left hepatic duct via the cystic duct or the accessory bile duct.

Abnormalities, Multiple↗