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Biomedical subjects

T Ikegami

Publications and source records attributed to T Ikegami.

At least 55 records · Page 3Linked to original sources
PubMed2000

Sonographic detection of visceral adhesion in percutaneous drainage of afferent-loop small-intestine obstruction.

To facilitate the percutaneous drainage of an afferent-loop small-intestine obstruction, we used sonography to detect visceral adhesions and select a safe puncture route. The portion of the small intestine that was fixed to the anterior abdominal wall was sonographically identified by using a high-frequency transducer to locate the area of restricted visceral sliding. The needle was then inserted into the intestine. In 3 cases, we have found that this technique improves the confidence of the physicians who perform the percutaneous drainage and may help to minimize the risks associated with the percutaneous drainage.

Afferent Loop Syndrome↗
PubMed2000

Effect of liver transplantation in a twin for biliary atresia on physical development and intellectual performance: report of a case.

A case of twins, one of whom suffered from biliary atresia, is described herein. Although the patient had been doing well until 11 years of age after previously undergoing a primary hepatic portoenterostomy, she had to then undergo a liver transplantation due to severe refractory cholangitis at 14 years of age. Although the patient's intellectual performance had severely declined due to the progression of her illness for several years, it completely recovered after the liver transplantation. In cases where the physical development in childhood has been well preserved, liver transplantation might therefore offer the chance for a full recovery of deteriorated intellectual performance.

Biliary Atresia↗
PubMed2000

Suppression of hepatic lesions in a murine graft-versus-host reaction by antibodies against adhesion molecules.

BACKGROUND/AIMS: The injection of parental CD4+ T cells into major histocompatibility complex (MHC) class II disparate F1 hybrid mice induced an autoimmune graft-versus-host reaction (GVHR) which is analogous to autoimmune liver diseases. The interaction of adhesion molecules such as vascular cell adhesion molecule-1 (VCAM-1) and very late antigen-4 (VLA-4) has been known to be profoundly involved in the trafficking of lymphocytes into the inflammatory tissues. The aim of this study was to clarify the role of VLA4 or VCAM-1 in the development of GVHR-induced hepatic lesions in our model. METHODS: B6 T spleen cells were injected into (B6.C-H-2bm12xB6) F1 mice intravenously. Anti-VLA-4 mAbs and/or anti-VCAM-1 mAbs were injected intraperitoneally at a dose of 2.5 mg/kg of each mAbs per body weight of mouse. We examined the changes in GVHR-induced hepatic lesions, serum levels of antimitochondrial antibodies (AMA) and cytokine mRNA expressions of liver-infiltrating lymphocytes using H.E. and immunohistochemical staining, enzyme-linked immunosorbent assay (ELISA), and reverse transcription-polymerase chain reaction (RT-PCR), respectively. RESULTS: Hepatic lesions of anti-VLA-4 mAbs-treated mice were inhibited compared with those of GVHR mice. However, the administration of mAbs did not interfere with the induction of splenomegaly, the invasion of CD4+, CD8+, B220+, or Mac-1+ cells around bile ducts, nor the production of AMA. Liver-infiltrating CD4+ T cells obtained from these treated mice did not alter the expression of T helper (Th)1 and Th2 cytokine mRNA. CONCLUSION: The results suggest that treatment with antibodies against these adhesion molecules could inhibit the infiltration of lymphocytes without affecting the Th1/Th2 balance. The blockade of VLA-4-mediated cell infiltration into the liver in this model may have a possible novel therapeutic role of VLA-4 mAbs.

Animals↗
PubMed2000

Effects of intrauterine IL-6 and IL-8 on the expression of surfactant apoprotein mRNAs in the fetal rat lung.

OBJECTIVE: The purpose of this study was to investigate the effect of interleukin-6 (IL-6) and interleukin-8 (IL-8), whose concentrations are elevated with chorioamnionitis, on the expression of surfactant apoprotein mRNAs in fetal rat lung. STUDY DESIGN: We employed an animal model in which we were able to administer substances continuously into the cavity between the fetal membranes and endometrium using a miniosmotic pump. Lipopolysaccharide (LPS), IL-6, or IL-8 was administered to timed pregnant rats for 3 days (day 16-19), and fetal lung expression of surfactant apoprotein mRNAs for SP (surfactant apoprotein)-A, SP-B, and SP-C was evaluated by Northern blot hybridization. RESULTS: Continuous administration of LPS increased the expression of each surfactant apoprotein mRNA, but the expression of mRNAs was not dose-dependent. On the other hand, continuous IL-6 or IL-8 administration increased the expression of each surfactant apoprotein mRNA in a dose-dependent manner. CONCLUSION: Fetal lung maturation may be promoted by either IL-6 or IL-8 produced in response to chorioamnionitis.

Animals↗
PubMed2000

Revascularization using the short gastric vessels of the gastric tube after subtotal esophagectomy for intrathoracic esophageal carcinoma.

BACKGROUND: Maintaining sufficient blood flow to the substitutive organ after esophagectomy is essential to decrease the risk of anastomotic leakage. STUDY DESIGN: Forty-one patients underwent subtotal esophagectomy for intrathoracic esophageal carcinoma and reconstruction using the gastric tube. Additional vascular anastomosis between the short gastric vessels and the vessels in the neck was performed in 15 patients. Tissue blood flow was measured by laser Doppler flowmetry before and after vascular anastomosis. The incidence of anastomotic leakage in the revascularization group was compared with that in the remaining 26 patients. RESULTS: Venous anastomosis was performed in 14 patients and arterial anastomosis in 9. There was a significant increase in tissue blood flow after venous anastomosis alone (mean percent increase: 36%; p < 0.01), and after arterial and venous anastomoses (mean percent increase: 108%; p < 0.01). No anastomotic leakage was observed in the revascularization group; six patients (23.1%) in the control group had leakage (p < 0.05). Patients in the revascularization group started taking a meal 10.0 +/- 0.4 days postoperatively, compared with 15.1 +/- 1.8 days in the control group (p < 0.05). CONCLUSIONS: Additional vascular anastomosis in esophageal reconstruction after subtotal esophagectomy achieved good results. This procedure can reduce the risk of anastomotic leakage and may be useful for esophageal reconstruction.

Aged↗
PubMed2000

Experimental study of the effects of deletion variant of hepatocyte growth factor on hepatic ischaemia-reperfusion injury.

BACKGROUND: Hepatic ischaemia-reperfusion (IR) injury is still a serious complication following liver surgery. The effect of the deletion variant of hepatocyte growth factor (dHGF) on hepatic IR injury was examined in rats. METHODS: Male Wistar rats were divided into two groups after 90 min of partial liver ischaemia: the dHGF group which was given dHGF 0.5 mg/kg intravenously immediately after reperfusion, followed by 0.5 mg/kg every 12 h, and the control group, which received vehicle buffer only. Serum chemistry, histopathological findings and liver weights were compared between the groups. RESULTS: In the dHGF group, the increase in serum alanine transaminase and hyaluronic acid levels was significantly reduced, and the serum albumin level increased after reperfusion. The extent of hepatic necrosis 24 h after reperfusion was decreased in the dHGF group. Moreover, the proportion of terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate nick end labelling-positive hepatocytes 6 h after reperfusion was reduced in the dHGF group. The non-ischaemic-, ischaemic- and whole-liver weight : body-weight ratio significantly increased in the dHGF group after reperfusion. The proportion of proliferating cell nuclear antigen-positive hepatocytes in the dHGF group markedly increased after 6 h after reperfusion in the non-ischaemic lobes, while in the ischaemic lobes it increased 24 h after reperfusion. CONCLUSION: These data suggest that dHGF not only improves recovery from IR injury, but also accelerates recovery from these injuries. dHGF may be an effective pharmacological agent for prevention and treatment of hepatic IR injury.

Animals↗
PubMed2000

Cytokine profile of liver-infiltrating CD4+ T cells separated from murine primary biliary cirrhosis-like hepatic lesions induced by graft-versus-host reaction.

BACKGROUND AND METHODS: We have previously reported that CD4+ T cells induced primary biliary cirrhosis (PBC)-like hepatic lesions in mice with graft-versus-host reaction due to major histocompatibility complex class II disparity. To clarify the relationship between the cytokine profile produced by CD4+ T cells and the formation of hepatic lesions, we sorted CD4+ T cells from the liver by using flow cytometry and examined their cytokine mRNA expression at various times after GVHR induction. We also examined the associated changes in the serum levels of antimitochondrial antibodies (AMA). RESULTS: Histologically, the infiltration of CD4+ T cells around the bile ducts was observed from day 5, and the lesions deteriorated gradually until day 14. On day 14, CD8+, B220+ and Mac-1+ cells, as well as CD4+ T cells were seen around the bile ducts. In the liver-infiltrating CD4+ T cells, the expression level of interferon-gamma (IFN-gamma) mRNA was observed to increase at an early phase (day 3), whereas that of interleukin (IL)-10 mRNA was elevated at a later phase (day 14). The elevation of IFN-gamma mRNA expression at an early phase before the appearance of non-suppurative destructive cholangitis suggests that IFN-gamma may be related to the pathogenesis of PBC in this model. Serum levels of AMA on day 14 were significantly higher than those on day 5. Interleukin-10 was considered to stimulate antibody production, to show an inhibitory effect upon the function of T helper 1 cells, and to inhibit fibrosis. CONCLUSIONS: Interferon-gamma may play an important role in the pathogenesis of this model. Moreover, delayed expression of IL-10 mRNA may control PBC-like hepatic lesions.

Animals↗
PubMed2000

Aggressive surgical approach to recurrent tumors after hepatectomy for metastatic spread of colorectal cancer to the liver.

BACKGROUND: Liver resection is currently accepted as the only potential cure for patients with metastases of colorectal tumors in the liver. However, cancer will recur in more than 70% of patients. METHODS: In the 7 years to December 1997, 60 patients underwent liver resections for colorectal metastases at our institute. Of these, 20 patients had repeated surgical resections for recurrent disease of the liver and other organs. Another 2 patients had undergone previous hepatectomy elsewhere. The clinical data for these patients were reviewed. RESULTS: The median interval between the 2 resections was 16 months. Eighteen hepatectomies, 6 lung resections, and 1 pancreatoduodenectomy were performed in 22 patients. Operative mortality and complication rates were 0% and 18%, respectively. At a median follow-up of 25 months after repeated resection, the survival rate in these patients was 73% at 2 years (12 of 16 evaluable patients are surviving) and 22% at 5 years (2 of 10 evaluable patients are surviving); the median survival time was 44 months. CONCLUSIONS: Repeated resections for recurrent colorectal metastases yield comparable results to first liver resections in operative mortality and morbidity rates, survival time, and pattern of recurrence. Although the number of patients surviving more than 5 years is still limited, the absence of other proven treatments supports the concept of an aggressive resectional approach for these patients.

Adult↗
PubMed2000

Inhalation toxicity of potassium octatitanate fibers (TISMO) in rats following 13 weeks of aerosol exposure.

One hundred and forty male and 140 female rats were divided into 1 control and 3 test groups of 35 rats each, per sex, and exposed by whole-body inhalation to test compound at target concentrations of 0, 1 mg/m(3) (1700 fibers/cm(3), 123 WHO fibers/cm(3)), 10 mg/m(3) (5900 fibers/cm(3), 952 WHO fibers/cm(3)), and 100 mg/m(3) (112,700 fibers/cm(3), 7440 WHO fibers/cm(3)) for 6 h/day, 5 days/wk for 13 wk. Ten rats from each group were killed after 13 wk of exposure and 13 wk of recovery, respectively, for histopathological evaluation. The other 15 rats from each group were killed to study lung clearance after 91 days of exposure, and approximately 1.5 and 3 mo of recovery following the end of the 13 wk of exposure. The mean fiber length of the chamber atmosphere was 2.8, 2.7, and 2.8 microm, while the mean fiber width was 0.48, 0.48, and 0.45 microm for the 1-, 10-, and 100-mg/m(3) chambers, respectively. In the 1-mg/m(3) (123 WHO fibers/cm(3)) exposure group, inhaled particles were mostly retained in a few fiber-laden alveolar macrophages (AMs) within the alveoli adjacent to alveolar ducts without any adverse tissue response throughout 13 wk of exposure and following 13 wk of recovery. This exposure concentration was considered to be a no-observable-adverse-effect level (NOAEL), since the alveoli containing fiber-laden AMs preserved normal structure. After 13 wk of exposure to 10 mg/m(3) (952 WHO fibers/cm(3)), fiber-laden AMs were mainly retained at the alveoli adjacent to the alveolar ducts. Infrequently, slight fibrotic thickening was observed in the alveolar ducts and adjoining alveoli, with proliferating fibroblasts and hyperplastic Type II pneumocytes, and microgranulomas. Occasionally, trace amounts of collagenous material were deposited in the thickened alveolar ducts and adjoining alveolar walls. In addition, minimal alveolar bronchiolarization was occasionally found in the alveoli adjacent to the terminal bronchioles. The peribronchial lymphoid tissue and thymic lymph nodes contained migrated fiber-laden AMs. After 13 wk of recovery, fiber-laden AMs had mostly disappeared from alveoli located in the peripheral acini, but they localized in the alveolar ducts region, suggesting there was active lung clearance of fibers by the AMs via airways. Thickened alveolar ducts and adjacent alveoli were decreased in thickness, a reversible change manifested by reduction of proliferating Type II pneumocytes and fibroblasts. Collagenized fibrosis was slightly more pronounced in the thickened alveolar ducts and adjoining alveoli. The lung response following 13 wk of exposure to 100 mg/m(3) (7440 WHO fibers/cm(3)) and after 13 wk of recovery was similar to those findings of the 952 WHO fibers/cm(3) group but more pronounced, demonstrating a clear concentration-related response. Alveolar ducts and adjoining alveolar walls in the central acini were irregularly thickened with more frequent evidence of minimal collagenized fibrosis. The lung burden and clearance of fibers were estimated by measuring the total content of titanium (Ti) in the lungs, but high variability of Ti content in control and exposed groups prevented meaningful lung clearance analysis.

Administration, Inhalation↗
PubMed2000

Impairment of cerebrovascular reactivity to acetazolamide in patients with normal pressure hydrocephalus.

Cerebrovascular reactivity (CVR) to acetazolamide was investigated in 41 patients with normal pressure hydrocephalus (NPH). The aetiology was subarachnoid haemorrhage in 20 patients, trauma in nine, brain tumour in three and idiopathic in nine. Mean cerebral blood flow (CBF) of the whole brain was measured by performing first-pass radionuclide angiography using 99Tcm-hexamethylpropylene++ amine oxime. Cerebrovascular reactivity was measured as the percentage change from the baseline mean CBF value after the administration of 500 mg of acetazolamide. Cerebrovascular reactivity was significantly (P < 0.001) reduced in patients with the complete triad of NPH (1.4 +/- 3.1%), regardless of the aetiology, compared with normal controls (14.7 +/- 3.3%). Patients with the incomplete triad also showed significantly (P < 0.05) reduced CVR (9.6 +/- 5.4%). Patients with the complete triad had significantly (P < 0.001) lower CVR than those with the incomplete triad. Post-operative CVR in both groups (20 patients with the complete triad and 9 patients with the incomplete triad) increased significantly, from 1.5 +/- 3.5% to 10.0 +/- 5.5% (P < 0.001) and from 8.7 +/- 4.9% to 14.9 +/- 5.4% (P < 0.05), respectively. Cerebrovascular reactivity is impaired in patients with NPH regardless of the aetiology and improves after shunting.

Acetazolamide↗
PubMed2000

RIKEN integrated sequence analysis (RISA) system--384-format sequencing pipeline with 384 multicapillary sequencer.

The RIKEN high-throughput 384-format sequencing pipeline (RISA system) including a 384-multicapillary sequencer (the so-called RISA sequencer) was developed for the RIKEN mouse encyclopedia project. The RISA system consists of colony picking, template preparation, sequencing reaction, and the sequencing process. A novel high-throughput 384-format capillary sequencer system (RISA sequencer system) was developed for the sequencing process. This system consists of a 384-multicapillary auto sequencer (RISA sequencer), a 384-multicapillary array assembler (CAS), and a 384-multicapillary casting device. The RISA sequencer can simultaneously analyze 384 independent sequencing products. The optical system is a scanning system chosen after careful comparison with an image detection system for the simultaneous detection of the 384-capillary array. This scanning system can be used with any fluorescent-labeled sequencing reaction (chain termination reaction), including transcriptional sequencing based on RNA polymerase, which was originally developed by us, and cycle sequencing based on thermostable DNA polymerase. For long-read sequencing, 380 out of 384 sequences (99.2%) were successfully analyzed and the average read length, with more than 99% accuracy, was 654.4 bp. A single RISA sequencer can analyze 216 kb with >99% accuracy in 2.7 h (90 kb/h). For short-read sequencing to cluster the 3' end and 5' end sequencing by reading 350 bp, 384 samples can be analyzed in 1.5 h. We have also developed a RISA inoculator, RISA filtrator and densitometer, RISA plasmid preparator which can handle throughput of 40,000 samples in 17.5 h, and a high-throughput RISA thermal cycler which has four 384-well sites. The combination of these technologies allowed us to construct the RISA system consisting of 16 RISA sequencers, which can process 50,000 DNA samples per day. One haploid genome shotgun sequence of a higher organism, such as human, mouse, rat, domestic animals, and plants, can be revealed by seven RISA systems within one month.

Animals↗
PubMed2000

Expression and characterization of the chitin-binding domain of chitinase A1 from Bacillus circulans WL-12.

Chitinase A1 from Bacillus circulans WL-12 comprises an N-terminal catalytic domain, two fibronectin type III-like domains, and a C-terminal chitin-binding domain (ChBD). In order to study the biochemical properties and structure of the ChBD, ChBD(ChiA1) was produced in Escherichia coli using a pET expression system and purified by chitin affinity column chromatography. Purified ChBD(ChiA1) specifically bound to various forms of insoluble chitin but not to other polysaccharides, including chitosan, cellulose, and starch. Interaction of soluble chitinous substrates with ChBD(ChiA1) was not detected by means of nuclear magnetic resonance and isothermal titration calorimetry. In addition, the presence of soluble substrates did not interfere with the binding of ChBD(ChiA1) to regenerated chitin. These observations suggest that ChBD(ChiA1) recognizes a structure which is present in insoluble or crystalline chitin but not in chito-oligosaccharides or in soluble derivatives of chitin. ChBD(ChiA1) exhibited binding activity over a wide range of pHs, and the binding activity was enhanced at pHs near its pI and by the presence of NaCl, suggesting that the binding of ChBD(ChiA1) is mediated mainly by hydrophobic interactions. Hydrolysis of beta-chitin microcrystals by intact chitinase A1 and by a deletion derivative lacking the ChBD suggested that the ChBD is not absolutely required for hydrolysis of beta-chitin microcrystals but greatly enhances the efficiency of degradation.

Amino Acid Sequence↗
PubMed2000

A novel auxiliary partial orthotopic liver transplantation model in rats.

BACKGROUND: Although auxiliary partial orthotopic liver transplantation (APOLT) has become a well-accepted procedure recently, a practical experiment model in APOLT using small animals has yet to be developed. METHODS: Male Lewis rats were used for both donors and recipients. An auxiliary partial graft was obtained by ex vivo resection of the donor right and caudate lobes, and was transplanted orthotopically into the recipient after resection of the recipient medial and left hepatic lobes. Portal vein and hepatic duct reconstructions were by the cuff technique, and supra- and intrahepatic vena cava were sutured continuously. Operative outcomes, serum chemistry, liver tissue blood flow, angiographic and histopathological findings were then examined. Conventional orthotopic liver transplantation (OLT) procedures were also undertaken as a control. RESULTS: One-day, 1-week and 1-month survival rate of APOLT group was 100, 85 and 85%, respectively. AST in the APOLT group on the 1st postoperative day was significantly higher than in the OLT group. No significant differences were recognized in serum albumin and total bilirubin levels between the two groups. Although the portogram of an APOLT rat showed slight narrowing at the cuff anastomosis site, both the graft and the native liver were opacified similarly. The liver tissue blood flow on the 5th postoperative day in the native liver and the graft returned to as high as 95 and 74% of the values on laparotomy, respectively. Histological examinations of the auxiliary graft 1 month after transplantation showed mild ductular proliferation and mononuclear cell infiltration around the portal triads. CONCLUSION: This novel APOLT model in rats allows practical and reproducible results, and may be of value in the basic study of APOLT procedures.

Angiography↗
PubMed2000

Open problems in artificial life.

This article lists fourteen open problems in artificial life, each of which is a grand challenge requiring a major advance on a fundamental issue for its solution. Each problem is briefly explained, and, where deemed helpful, some promising paths to its solution are indicated.

Artificial Intelligence↗
PubMed2000

Application of a newly developed photoluminescence glass dosimeter for measuring the absorbed dose in individual mice exposed to low-dose rate 137Cs gamma-rays.

A photoluminescence glass dosimeter, GD-301, was applied to the measurement of low absorbed doses in mice exposed to low-dose rate 137Cs gamma-rays. The dosimeter system consists of small rod-shaped glass chip detectors capable of embedded in the body of a mouse and an automatic readout device equipped with a standard detector irradiated with 137Cs gamma-source. The measured absorbed doses were compared with the "exposure" estimated by an ionization chamber and with the doses measured by a BeO:Na thermoluminescence system. The results clearly demonstrate the superiority of the glass dosimetry regarding simplicity of operation, stability of long-term dose accumulation and good detector uniformity, which allow accurate tissue dosimetry.

Animals↗
PubMed1999

Partial-liver transplantation to treat familial amyloid polyneuropathy: follow-up of 11 patients.

BACKGROUND: Recently, liver transplantation has been used to treat patients with familial amyloid polyneuropathy (FAP). OBJECTIVE: To describe the clinical course of patients with FAP who received partial-liver transplantation from living donors. DESIGN: Case series. SETTING: University hospital in Matsumoto, Japan. PATIENTS: 11 patients with FAP who underwent partial-liver transplantation. The transthyretin gene abnormality in all 11 patients was the substitution of methionine for valine at position 30. INTERVENTION: Partial liver transplantation from living donors. MEASUREMENTS: Preoperative and follow-up (3 to 64 months) clinical data, including routine laboratory data, nerve conduction velocity tests, and sural nerve histology. RESULTS: All 7 patients who had severe gastrointestinal autonomic disorders or polyneuropathy localized to the lower limbs for less than 4 years showed improvement. Three of 4 patients with polyneuropathy involving both the upper and lower limbs had adverse outcomes, including two deaths. The preoperative duration of their illness was more than 6 years. These 3 patients also had marked decreases in creatinine clearance and nerve conduction velocities and severe loss of myelinated fibers in sural nerves. CONCLUSION: Preoperative clinical severity and duration of illness are associated with outcomes after liver transplantation for FAP.

Adult↗