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Biomedical subjects

Taro Yamashita

Publications and source records attributed to Taro Yamashita.

At least 19 recordsLinked to original sources
PubMed2025

KRAS Mutations in Duodenal Lavage Fluid After Secretin Stimulation for Detection of Pancreatic Cancer.

OBJECTIVE: Although pancreatic ductal adenocarcinoma (PDAC) is still a devastating disease, the survival rate for surgically removed PDACs has significantly improved in recent years. Early detection is essential in managing PDAC. BACKGROUND: The presence of KRAS mutations in PDAC leads to the initial genetic abnormality and offers a significant timeframe for identifying resectable PDACs. A minimally invasive and highly specific PDAC screening test is necessary to prevent the need for invasive follow-up tests. METHODS: Between July 2021 and March 2023, 169 cases were enrolled in 7 institutions. By administering secretin before esophagogastroduodenoscopy (EGD), the excretion of pancreatic juice into the papillary fluid can be stimulated, creating a resource for testing. Washing fluid was collected using a specialized catheter from control individuals (n=75) and patients with resectable PDAC (n=89) at the initial diagnosis. A highly sensitive technique was employed to study KRAS gene mutations. RESULTS: This study obtained an AUC of 0.934 (95% CI: 0.904, 0.964) when using KRAS mutations in duodenal lavage fluid to differentiate between patients with resectable PDAC and healthy controls. The estimated sensitivities were calculated with specificity set at 100%, resulting in a sensitivity of 83.1% (95% CI: 71.7%, 91.2%). The McNemer test showed a significantly higher sensitivity for KRAS mutations than serum CEA and CA19-9 ( P <0.0001). CONCLUSIONS: We created a method to identify resectable PDACs by analyzing KRAS mutation levels in duodenal fluid collected during EGD with secretin stimulation of pancreatic juice secretion.

Humans↗
PubMed2006

A transgenic rat with the human ATTR V30M: a novel tool for analyses of ATTR metabolisms.

Amyloidogenic transthyretin (ATTR) is the pathogenic protein of familial amyloidotic polyneuropathy (FAP). To establish a tool for analyses of ATTR metabolisms including after liver transplantations, we developed a transgenic rat model expressing human ATTR V30M and confirmed expressions of human ATTR V30M in various tissues. Mass spectrometry for purified TTR revealed that rat intrinsic TTR and human ATTR V30M formed tetramers. Congo red staining and immunohistochemistry revealed that nonfibrillar deposits of human ATTR V30M, but not amyloid deposits, were detected in the gastrointestinal tracts of the transgenic rats. At 24h after liver transplantation, serum human ATTR V30M levels in transgenic rats that received livers from normal rats became lower than detectable levels. These results thus suggest that this transgenic rat may be a useful animal model which analyzes the metabolism of human ATTR V30M including liver transplantation studies.

Amyloid Neuropathies, Familial↗
PubMed2006

FK506 inhibits murine AA amyloidosis: possible involvement of T cells in amyloidogenesis.

OBJECTIVE: To determine the possibility that T cells represent a potential target for therapy in AA amyloidosis. METHODS: AA amyloidosis was induced in C3H/HeN mice by concomitant administration of AgNO3 and amyloid-enhancing factor (AEF). Mice injected with AgNO3 and AEF received intraperitoneal injections of FK506 (2-200 microg/day). The degree of splenic amyloid deposition was determined by Congo red staining. Serum amyloid A (SAA), interleukin 1beta (IL-1beta), IL-6, and tumor necrosis factor-a concentrations were measured by ELISA. AA amyloidosis was also induced in ICR mice by injection of Freund's complete adjuvant (FCA) and Mycobacterium butyricum without AEF. ICR mice injected with FCA and M. butyricum also received intraperitoneal injections of FK506 (200 microg/day) to eliminate the possibility that FK506 action might depend upon AEF activity in the amyloid formation. Amyloid deposition was also induced with and without AEF in severe combined immunodeficient (SCID) mice and nude mice to clarify the role of T cells in the mechanism of amyloid formation in AA amyloidosis. RESULTS: FK506 treatment significantly reduced the amount of amyloid deposition and incidence of amyloidosis without reducing serum SAA and proinflammatory cytokine levels in the murine AA amyloidosis models with and without AEF. SCID mice and nude mice showed resistance to development of AA amyloidosis. CONCLUSION: Our findings may provide a new therapeutic strategy for amyloidosis. The results suggested that T cells may play an important role in the mechanism of amyloid formation in AA amyloidosis.

Amyloidosis↗
PubMed2006

Surface exposed epitopes and structural heterogeneity of in vivo formed transthyretin amyloid fibrils.

We have investigated the structure of in vivo formed transthyretin (TTR) amyloid deposits by using antisera raised against short linear sequences of the TTR molecule. In immunohistochemistry, antisera anti-TTR41-50 and anti-TTR115-124-a reacted specifically with both wildtype ATTR and ATTR V30M material, whereas only anti-TTR41-50 recognized ATTR Y114C material. Similar results were obtained by ELISA analysis of ATTR V30M and ATTR Y114C vitreous amyloid, where the anti-TTR115-124-a antiserum failed to react with ATTR Y114C material. Moreover, neither of the antisera recognized natively structured TTR present in pancreatic alpha cells. Our results strongly indicate that the TTR molecule undergoes structural changes during fibrillogenesis in vivo. The finding of a structural difference between wildtype ATTR and ATTR V30M material on one hand and ATTR Y114C material on the other suggests that the fibril formation pathway of these ATTR variants may differ in vivo.

Amino Acid Sequence↗
PubMed2006

Different signaling pathways in the livers of patients with chronic hepatitis B or chronic hepatitis C.

The clinical manifestations of chronic hepatitis B (CH-B) and chronic hepatitis C (CH-C) are different. We previously reported differences in the gene expression profiles of liver tissue infected with CH-B or CH-C; however, the signaling pathways underlying each condition have yet to be clarified. Using a newly constructed cDNA microarray consisting of 9614 clones selected from 256,550 tags of hepatic serial analysis of gene expression (SAGE) libraries, we compared the gene expression profiles of liver tissue from 24 CH-B patients with those of 23 CH-C patients. Laser capture microdissection was used to isolate hepatocytes from liver lobules and infiltrating lymphoid cells from the portal area, from 16 patients, for gene expression analysis. Furthermore, the comprehensive gene network was analyzed using SAGE libraries of CH-B and CH-C. Supervised and nonsupervised learning methods revealed that gene expression was correlated more with the infecting virus than any other clinical parameters such as histological stage and disease activity. Pro-apoptotic and DNA repair responses were predominant in CH-B with p53 and 14-3-3 interacting genes having an important role. In contrast, inflammatory and anti-apoptotic phenotypes were predominant in CH-C. These differences would evoke different oncogenic factors in CH-B and CH-C. In conclusion, we describe the different signaling pathways induced in the livers of patients with CH-B or CH-C. The results might be useful in guiding therapeutic strategies to prevent the development of hepatocellular carcinoma in cases of CH-B and CH-C.

Adolescent↗
PubMed2006

A precise pharmacodynamic study showing the advantage of a marked reduction in cardiotoxicity in continuous infusion of doxorubicin.

We have already shown that the antileukemic activity of daunorubicin that had been reported to be dependent on the area under the concentration - time curve (AUC) was actually peak concentration (Cmax) dependent. The antitumor activity of doxorubicin (DXR) has also been reported to be dependent on AUC, whereas its cumulative cardiotoxicity has been reported to be Cmax dependent. In this study, we evaluated whether the antileukemic and cardiotoxic effects of DXR were AUC or Cmax dependent, and compared their cytotoxic effects, utilizing the computer-controlled in vitro pharmacokinetic simulation system or a conventional culture system for a leukemic cell line and measuring the intracellular ATP amount or the proportion of beating cells for the cardiotoxicity. In leukemic cells, the cytotoxic rate decreased as the simulated infusion time or exposure time increased with the same AUC value in the simulation and conventional culture system (P < 0.05 and <0.01, respectively). The intracellular ATP and proportion of beating cells also increased with prolonged DXR exposure time with the same constant concentration - time product value (P < 0.05 and <0.0001, respectively) in heart cells. These results indicated that both the antileukemic effects and the cardiotoxicity were Cmax dependent. However, a comparison of the two showed that cardiotoxicity was more Cmax dependent than the antileukemic effect. These results suggested that the continuous infusion treatment schedule of DXR may have the clinical advantage of reducing cardiotoxicity more markedly than the antileukemic effect.

Adenosine Triphosphate↗
PubMed2006

Lipid droplets are present in amyloid deposits in familial amyloidotic polyneuropathy and dialysis related amyloidosis.

It has been well documented that transthyretin (TTR) shows an affinity for lipoproteins and amyloid is deposited around adipocytes in patients with familial amyloidotic polyneuropathy (FAP). We examined the involvement of lipids in amyloid fibrils in the tissues by histopathologic methods. Sudan black B staining for frozen tissues of autopsied FAP patients and biospied dialysis related amyloidosis (DRA) patients revealed colocalization of lipids in the tissue sections where Congo red staining was positive, while no such positive staining was observed in paraffin embedded tissues. Immunohistochemical study using lipoprotein antibodies revealed that only anti-high density lipoprotein (HDL) antibody showed immunoreactivity in both types of amyloid specimens where Congo red was positively stained. Measurement of the components of lipids in the frozen cardiac samples from an FAP patient and an amyotrophic lateral sclerosis (ALS) patient revealed that concentrations of triglyceride and cholesterol in each lipoprotein, except for HDL-triglyceride, were markedly elevated in the FAP patient's material, compared to that of the ALS patient. These results suggest that interaction of amyloid fibrils with HDL may play an important role in amyloid formation in FAP.

Adult↗
PubMed2006

Severe congestive heart failure with cardiac liver cirrhosis 10 years after orthotopic liver transplantation for familial amyloidotic polyneuropathy.

Reported herein is an autopsy case of familial amyloidotic polyneuropathy (FAP) with cardiac liver cirrhosis associated with amyloid cardiomyopathy after liver transplantation. At 47 years of age a Japanese woman with a transthyretin Val30Met mutation and sensorimotor polyneuropathy underwent liver transplantation; no postoperative deterioration related to the graft or polyneuropathy occurred. However, cardiovascular dysfunction associated with amyloid deposition gradually worsened. Pacemaker implantation and diuretics were ineffective against the heart failure; 10 years after transplantation the patient died. Autopsy revealed massive pleural and pericardial effusions and amyloid cardiomyopathy, especially in the right atrium and cardiac conduction system. Amyloid deposition was slight in all organs except the heart, but liver cirrhosis with reversed lobulation and centrilobular hemorrhagic necrosis was prominent. There was no histological evidence for chronic liver graft rejection. These findings suggest that liver transplantation effectively stopped amyloid deposition and ameliorated clinical FAP symptoms but that amyloid cardiomyopathy after liver transplantation in advanced clinical stages may lead to severe congestive heart failure and cardiac liver cirrhosis.

Adult↗
PubMed2006

[Seizure-induced transient brain edema in the medial temporal lobe].

We reported a patient with sudden onset seizure resulting in prolonged amnesia. MRI revealed a T2 high signal lesion with swelling in the right medial temporal lobe. Because the MRI lesion remained to be the same in size for two months, biopsy specimens were obtained under informed consent to rule out the brain tumor. Based on histological findings showing brain edema without specific abnormal findings (malignancy, inflammation etc), we concluded that the temporal lesion was the edema induced by the seizure attack. In Japan, many papers on non-herpetic acute limbic encephalitis (NHALE) have recently been published. In their reports, seizures were frequently observed as a preceding symptom; moreover, clinical courses and MRI findings are similar to those of seizure-induced brain edema. The secondary brain edema induced by the seizure must be considered in patients with NHALE and other CNS disorders, especially if the patient has a history of the recent seizure.

Adult↗
PubMed2006

[Primary intraosseous cavernous hemangioma in anterior clinoid process].

Primary intraosseous cavernous hemangiomas (PICHs) are rare tumors, and there are no previous reports of cases with a tumor at the anterior clinoid process. We report a case of a PICH at the anterior clinoid process in a 66-year-old female presenting with headaches and visual impairment. CT and MR imaging showed a mass in the anterior clinoid process. The lesion showed hyperintensity on T1- and T2-weighted imaging, and gadolinium was homogenously enhanced. The lesion was removed surgically, and histologically confirmed as a cavernous hemangioma. Preoperative examinations could not provide a definitive diagnosis. A brief clinical and radiological review of the literature is presented.

Aged↗
PubMed2005

Ocular amyloid angiopathy associated with familial amyloidotic polyneuropathy caused by amyloidogenic transthyretin Y114C.

PURPOSE: To report the clinicopathological findings for a unique ocular amyloid angiopathy in patients with familial amyloidotic polyneuropathy (FAP) caused by amyloidogenic transthyretin Y114C. DESIGN: Three case reports. METHODS: Retrospective review of clinicopathological findings, course, and treatment of the 3 patients. MAIN OUTCOME MEASURES: Visual acuity, intraocular pressure, fundus photography, fluorescein angiography (FA), indocyanine green angiography, and histopathological analysis. RESULTS: In the 32-year-old patient, in the early stage of FAP, indocyanine green angiography demonstrated multiple sites of hyperfluorescence, with staining along major choroidal veins. Retinal vessels appeared normal clinically and on FA. In the 48-year-old patient, who had late-stage FAP, examination of the fundus revealed pinpoint white amyloid opacities over the retinal surface, sheathing of retinal vessels, and scattered retinal hemorrhages. Fluorescein angiography showed vascular closure, focal staining, and microaneurysms. Indocyanine green angiography revealed multiple sites of hyperfluorescence, with staining along retinal and choroidal vessels. Examination during follow-up revealed that these vascular changes continued to progress. Histopathological study of an eye obtained at autopsy from the 49-year-old patient revealed marked intravascular and extravascular amyloid deposition. CONCLUSIONS: Severe and progressive amyloid angiopathy causing visual disturbance was seen in patients with FAP caused by amyloidogenic transthyretin Y114C.

Adult↗
PubMed2005

cDNA microarray analysis of autoimmune hepatitis, primary biliary cirrhosis and consecutive disease manifestation.

While autoimmune hepatitis (AIH) and primary biliary cirrhosis (PBC) usually have distinct clinical manifestations, some patients present with features of both conditions. Using cDNA microarrays, we analyzed and compared gene expression profiles in 8 patients with AIH, 9 with PBC, 8 with chronic hepatitis C (CHC), 8 with non-alcoholic steatohepatitis (NASH) and 9 with normal livers. We subsequently applied this method to a tissue sample from a 61-year-old woman with overlapping features of both AIH and PBC. A 61-year-old woman was admitted to our hospital for evaluation of elevated serum alkaline phosphatase. A liver biopsy showed accumulation of mononuclear cells around the bile duct cells, a feature characteristic of chronic non-suppurative destructive cholangitis (CNSDC). Three years later, her serum alanine aminotransferase (ALT) level had increased, and a liver biopsy demonstrated evidence of a severe form of hepatitis. A cDNA microarray analysis of both biopsies identified the molecular events associated with her altered histology. The expression profile of this patient, which was originally different from that of the other PBC patients, changed to an AIH pattern. Our results suggest that this patient has characteristics of both AIH and PBC.

Aged↗
PubMed2005

Differential gene alteration among hepatoma cell lines demonstrated by cDNA microarray-based comparative genomic hybridization.

We assayed chromosomal abnormalities in hepatoma cell lines using the microarray-based comparative genomic hybridization (array-CGH) method and investigated the relationship between genomic copy number alterations and expression profiles in these hepatoma cell lines. We modified a cDNA array-CGH assay to compare genomic DNAs from seven hepatoma cell lines, as well as DNA from two non-hepatoma cell lines and from normal cells. The mRNA expression of each sample was assayed in parallel by cDNA microarray. We identified small amplified or deleted chromosomal regions, as well as alterations in DNA copy number not previously described. We predominantly found alterations of apoptosis-related genes in Hep3B and HepG2, cell adhesion and receptor molecules in HLE, and cytokine-related genes in PLC/PRF/5. About 40% of the genes showing amplification or loss showed altered levels of mRNA (p < 0.05). Hierarchical clustering analysis showed that the expression of these genes allows differentiation between alpha-fetoprotein (AFP)-producing and AFP-negative cell lines. cDNA array-CGH is a sensitive method that can be used to detect alterations in genomic copy number in tumor cells. Differences in DNA copy alterations between AFP-producing and AFP-negative cells may lead to differential gene expression and may be related to the phenotype of these cells.

Apoptosis↗
PubMed2005

Muscular amyloid angiopathy with amyloidgenic transthyretin Ser50Ile and Tyr114Cys.

Among patients with familial amyloid polyneuropathy (FAP), those with transthyretin Val30Met mainly show distally predominant weakness and atrophy, whereas some FAP patients, including those with transthyretin Ser50Ile and Tyr114Cys, show muscle weakness and atrophy that is dominant proximally, simulating myopathy. To clarify the cause of proximally dominant muscular atrophy in patients with FAP transthyretin Ser50Ile and Tyr114Cys, we investigated the distinctive features of muscle specimens of patients with FAP, 3 of who had Val30Met, 2 Ser50Ile, and 2 Tyr114Cys transthyretin. All specimens showed transthyretin amyloid around blood vessels and perimysium, and neurogenic denervation patterns. The amount of amyloid around the vessels was much greater in patients with FAP Ser50Ile and Tyr114Cys than in Val30Met patients. Muscular amyloid angiopathy may contribute to motor nerve injury that, in turn, may lead to amyotropic changes in patients with FAP Ser50Ile and Tyr114Cys.

Adult↗
PubMed2005

A prospective evaluation of the transthyretin Ile122 allele frequency in an African-American population.

Transthyretin Val122Ile is one of greater than 80 mutations in transthyretin (TTR) that are associated with hereditary amyloidosis. Retrospective studies have shown a prevalence of this mutation as high as 3.9% in African-Americans. The present study was undertaken to determine in a prospective fashion the prevalence of the TTR Val122Ile allele in African-Americans in a Midwestern American city. DNA was isolated from cord bloods collected at the time of birth in the County hospital of Indianapolis, Indiana. Samples were identified only as to ethnic origin of the mother. Analysis was performed by PCR amplification of TTR exon 4 followed by SSCP and RFLP. Cord bloods from 1,973 children born at the County hospital were analyzed. Thirty of 1,000 DNA samples from African-American newborns were positive for TTR Val122Ile (3%). Two of 453 DNA samples from Caucasian newborns were positive (0.44%). Zero of 490 DNA samples from newborns of Hispanic mothers and 0 of 30 from newborns with mothers classified as other (including Asian) were positive. This prospective study demonstrates that 3% of newborns of African-American women in an urban population have the TTR Val122Ile mutation which is associated with late-onset cardiomyopathy. The degree of penetrance of this mutation at the clinical level has not yet been determined.

Alleles↗
PubMed2005

Differential gene expression profiles in stage I primary biliary cirrhosis.

OBJECTIVES: Primary biliary cirrhosis (PBC) is a progressive disease. However, little is understood about the molecular mechanisms underlying its features. METHODS: We analyzed gene expression profiles of liver biopsy samples from 16 patients with PBC, seven with autoimmune hepatitis, eight with chronic hepatitis C, and eight normal control livers. In addition to whole liver samples, we selectively analyzed chronic nonsuppurative destructive cholangitis (CNSDC) lesions by laser capture microdissection. RESULTS: Hierarchical clustering analysis using only early-stage liver disease demonstrated 85 genes were upregulated in stage I PBC specifically. Surprisingly, the expression of these genes was not maintained in advanced-stage PBC, while other gene clusters were upregulated. Expression analysis of CNSDC lesions in stage I PBC showed the presence of active inflammatory changes, characterized by the significant elevation of interferon-gamma and the development and maturation of lymphocytes. Expression of these genes was diminished in lymphoid cells aggregation in stage III PBC, and genes reflecting hepatocyte damage were upregulated with disease progression. CONCLUSION: Gene expression patterns in stage I PBC are different from others. There are distinct changes in molecular pathology from early- to late-stage PBC, which might be a clue to reveal the etiology and progression of PBC.

Aged↗
PubMed2005

Transthyretin-related familial amyloid polyneuropathy: evaluation of CSF enhancement on serial T1-weighted and fluid-attenuated inversion recovery images following intravenous contrast administration.

BACKGROUND AND PURPOSE: CSF enhancement on MR images after intravenous administration of gadolinium chelate, which mimics subarachnoid hemorrhage, has been reported. The purpose of this study was to determine whether CSF enhancement can be seen on serial MR images following administration of contrast material in patients with transthyretin-related familial amyloid polyneuropathy (FAP) and to assess other ancillary MR findings. METHODS: We serially studied T1-weighted and fluid-attenuated inversion recovery (FLAIR) images of the brain before, immediately after, and 3, 6, and 24 hours after contrast administration in 6 patients with genetically confirmed transthyretin-related FAP. By consensus, 2 radiologists assessed the presence, degree, and extent of enhancement of the CSF, leptomeninges, brain parenchyma, and other structures. Statistical analysis was performed to define the difference of the enhancement between the 2 MR imagings. RESULTS: In 3/6 patients with cysteine-for-tyrosine substitutions at position 114 (Tyr114Cys mutations), marked CSF enhancement was observed on the FLAIR images at 3 and 6 hours and on T1-weighted images at 3 hours after contrast administration. Although there was no significant difference between the 2 MR imagings, leptomeningeal enhancement for these 3 patients was evident only on FLAIR images. The labyrinth and vitreous body was also enhanced on postcontrast delayed MR images of these 3 patients. These enhancements were not observed in the other 3 patients with Val30Met mutation. In none of the 6 patients did images demonstrate parenchymal enhancement of the brain. CONCLUSION: In FAP patients with Tyr114Cys mutations, contrast material can leak into the CSF. This finding may depend on the subtype of FAP and be more evident with FLAIR images. The enhancement of the leptomeninges, labyrinth, and vitreous body was also seen in the patients.

Adult↗