Biomedical subjects

Masato Igarashi

Publications and source records attributed to Masato Igarashi.

11 recordsLinked to original sources

PubMed2004

Liver metastasis 30 years after enucleation of the left eyeball for choroidal melanoma.

Here, we report a case of 70-year-old female with metastatic choroidal melanoma in the liver, which was detected 30 years after enucleation of the left eyeball. At first, two hypovascular tumors (4cm and 1cm in diameter) were detected in the liver as high-density areas on plain computed tomography (CT). They were demonstrated as hyper- and hypo-intensity lesions on T1- and T2-weighted image of magnetic resonance imaging (MRI), respectively, with superparamagnetic iron oxide uptake. During about 2-years follow-up, the larger tumor did not change significantly in size and in the character. However, the smaller one grew up in size and changed its nature to hypervascular and hyper-intensity on T2-weighted image of MRI. These hypervascular tumors increased in number and in size rapidly. The specimens obtained with tumor biopsy revealed epithelioid tumor cells positive for HMB45 immunohistochemical stain with and without brown pigment, and the tumors were diagnosed as melanoma. The patient underwent transcatheter arterial chemoembolization with cisplatin and epirubicin hydrochloride, and subsequent transcatheter arterial infusion chemotherapy with cisplatin, nimustine and dacarbazine. Unfortunately, however, the tumor rapidly progressed and she died. We discuss the imaging of the melanoma metastasized to the liver with the estimation of doubling time (DT) of the tumors.

Journal Article↗

PubMed2004

Increased hTR expression during transition from adenoma to carcinoma is not associated with promoter methylation.

Human telomerase RNA component (hTR) expression, which increases in the majority of cancer cells with an acquisition of telomerase activity, was concomitantly evaluated with methylation status and human telomerase reverse transcriptase (hTERT) expression in colorectal cancers and precursor lesions. hTR and hTERT expressions were detected by in situ hybridization and reverse transcription following polymerase chain reaction, respectively, in 15 colonic adenomas, 19 sporadic colonic cancers at various histological stages, and 3 normal colonic mucosa samples. The methylationstatus of hTR was evaluated by methylation-specific polymerase chain reaction following restriction endonuclease digestion and direct sequencing. hTERT expression was detected in 16 of 19 cancers. hTR expression was detected in all cancers including two cases of intramucosal carcinoma. No hTR signals were detected in the normal epithelium or in the adenomas with severe atypism. CpG dinucleotides in the 5'-untranslated region of hTR were completely unmethylated from -204 to -3 and mosaically methylated from -290 to -272, irrespective of the atypism. These results suggest that hTR expression is increased at the adenoma-to-carcinoma transition stage but is not always associated with hTERT expression. Hypomethylation of the hTR promoter region is not likely to be the main mechanism regulating hTR expression.

Adenocarcinoma↗

PubMed2004

Inductive effects of dexamethasone on the gene expression of Cbfa1, Osterix and bone matrix proteins during differentiation of cultured primary rat osteoblasts.

Runx2/core binding factor alpha 1 (Cbfa1) and Osterix (Osx) are osteoblast-specific transcription factors essential for the development of a mature osteoblast phenotype and are thought to activate osteoblast marker genes in vivo to produce a bone-specific matrix. Dexamethasone (Dex) is known to be a potent stimulator of osteoblastic differentiation in vitro, however, the exact role is still unclear. To investigate the mechanisms of the stimulation of osteoblastic differentiation by Dex, we evaluated the effects of Dex on proliferation and mineralization as well as on mRNA expression of Cbfa1, Osx and osteoblast marker genes, osteocalcin (OC) and bone sialoprotein (BSP) mRNAs in differentiating foetal rat calvarial cells (FRCC), which were cultured for 35 days in the presence or absence of 10(-7) M Dex. Treatment of FRCC with Dex resulted in the stimulation of cell proliferation and increased the number of cells, which are able to produce bone-like nodules with a mineralized matrix when compared to untreated controls. Northern blot analysis revealed that, in the absence of Dex, Cbfa1 mRNA expressed at day 8, while Osx mRNA expressed at day 15. Subsequently expression of these mRNAs increased up to day 21, followed by constant expression during the culture period. The expression of OC and BSP mRNAs appeared to be synchronous with that of Osx mRNA and was detectable at day 15 with an increase thereafter. The presence of Dex resulted in an induction in Cbfa1 and Osx mRNA expression. The former appeared at day 5 and the latter appeared at day 11. Subsequently expression of Cbfa1 and Osx mRNAs increased up to day 15 with a decrease thereafter. Expression of OC and BSP mRNAs appeared to be coincident with that of Osx mRNA and was detectable at day 11 and reached a maximum at day 15 followed by constant expression. These observations indicate that induction of Cbfal and Osx mRNAs by Dex may be followed by activation of osteoblast marker genes such as OC and BSP mRNAs to produce a bone-specific matrix that subsequently becomes mineralized. Thus, it is likely that Dex may promote osteoblastic differentiation and mineralization of FRCC by inducing the expression of Cbfa1 and Osx genes in vitro.

Alkaline Phosphatase↗

PubMed2003

Interferon can block telomere erosion and in rare cases result in hepatocellular carcinoma development with telomeric repeat binding factor 1 overexpression in chronic hepatitis C.

PURPOSE: The purpose of this study was to evaluate whether IFN therapy for chronic hepatitis C could overcome telomere reduction in the liver, a possible risk factor for hepatocellular carcinoma (HCC) development. EXPERIMENTAL DESIGN: Relative telomeric repeat content (RTC) in the liver was measured before and after IFN therapy in 21 chronic hepatitis C cases. Liver samples were obtained at average intervals of 12, 75, and 32 months in eight complete responders (CRs) and one biochemical responder (BR), four CRs in whom HCC developed after an eradication of hepatitis C virus, and eight nonresponders, respectively. Telomeric repeat binding factor 1 (TRF1) was immunostained in specimens from CRs and a BR. RESULTS: Although the average RTC of 0.96 +/- 0.14 (mean +/- SD) significantly decreased to 0.85 +/- 0.12 after IFN therapy in nonresponders (P = 0.023), the value of 0.91 +/- 0.14 before IFN therapy in CRs and a BR increased significantly to 1.0 +/- 0.085 (P = 0.031). TRF1 expression was barely detectable and attenuated after IFN therapy, except in CRs developing HCC, in which frequent staining appeared, and the RTC evidently decreased from 0.97 +/- 0.11 to 0.63 +/- 0.0092 in corresponding noncancerous liver tissues. CONCLUSIONS: It is strongly suggested that successful IFN therapy blocks telomere erosion, except in rare cases in which telomere reduction continues with overexpression of TRF1. Successive RTC evaluation in the liver may distinguish a risky case from a clinically cured one.

Antineoplastic Agents↗

PubMed2003

Sensitive and specific detection of circulating cancer cells in patients with hepatocellular carcinoma; detection of human telomerase reverse transcriptase messenger RNA after immunomagnetic separation.

PURPOSE: We evaluated whether detection of human telomerase reverse transcriptase (hTERT) mRNA after immunomagnetic separation is useful to detect circulating cancer (CC) cells. EXPERIMENTAL DESIGN: Two ml of peripheral blood were collected from 55 cases with hepatocellular carcinoma (HCC), 20 cases with chronic liver diseases devoid of cancer, and 20 healthy volunteers. Then 1500 and 500 micro l were subjected to immunomagnetic separations using Ber-EP4 and anti-CD45 antibodies, harvested and supernatant cells were collected as epithelial and nonleukocyte fractions, respectively. Samples of each fraction were subjected to reverse transcription-PCR detecting beta-actin, interleukin-2 receptor (IL-2r), alpha-fetoprotein, and hTERT mRNAs. The cases were judged to be positive, equivocal, or negative for CC cells when hTERT positivity with IL-2r negativity, hTERT positivity with IL-2r positivity, or hTERT negativity was seen in epithelial and/or nonleukocyte fractions, respectively. RESULTS: The dilution experiments revealed that our system could detect 10(0-1) HeLa cells involved in 2 ml of blood. The Ber-EP4-harvested cells from cases with distant metastasis were positive for immunostaining using Hep Par 1 monoclonal antibody. CC cells were judged to be positive in 29 of 55 (53%) HCC cases. On the contrary, no cases without HCC were determined to be positive. The frequency of positivity was significantly correlated with disease extent of HCC. CONCLUSIONS: These results strongly suggest that detection of hTERT mRNA after immunomagnetic separation is a specific and sensitive tool to detect CC cells and that it would provide useful source for further investigation of cancer metastasis.

Aged↗

PubMed2003

Telomere length variation and maintenance in hepatocarcinogenesis.

BACKGROUND: Despite the recent discovery of interchromosomal telomere length variation, a role for heterogeneity in telomere maintenance has yet to be established. This study investigated the significance of telomere length variation between chromosomes with respect to the association of cancer progression and telomere length regulation. METHODS: Terminal restriction fragment (TRF) was evaluated in 20 surgically resected hepatocellular carcinoma specimens (HCC), corresponding noncancerous liver tissue specimens (NCL), and in 10 liver tissue specimens with chronic liver diseases devoid of cancer (DOC). Average TRF length (TRF-A) was defined as the point of maximum intensity. Shorter and longer TRF lengths (TRF-S and TRF-L) were defined as the length above which 90% of TRF distribution was involved. A ratio, (TRF-L-TRF-S)/TRF-A, was defined as telomere length dispersion. RESULTS: The dispersion was significantly larger in HCC than in NCL specimens (P = 0.012) and in NCL than in DOC (P = 0.048). TRF-A and TRF-S were significantly shorter in HCC than in NCL (P = 0.0026, P = 0.0010). In seven patients in whom HCC recurred within 1 year, TRF-A and TRF-S were significantly shorter than in 10 patients in whom recurrence occurred after 1 year (P = 0.018, P = 0.0097). Telomeric repeat binding factor 1 was up-regulated in HCC with elongated TRF-L, whereas expression of human telomerase reverse transcriptase was greater in HCC with a shorter TRF-S. CONCLUSIONS: These results suggest that telomere length varied through chronic liver diseases by preferentially increasing shorter telomeres, whose length is a good indicator for malignant potential of HCC. Telomere length variation may be a crucial code in telomere maintenance through hepatocarcinogenesis.

Aged↗

PubMed2002

Interchromosomal telomere length variation.

Despite the recent discovery of interchromosomal telomere length variation, a role for heterogeneity in telomere maintenance has yet to be established. This study aimed to clarify relative telomere length differences between chromosomes. Combined chromosomal sorting and telomeric repeat content analysis in GM130B cells, the relative telomeric repeat content in each chromosome, were calculated. Each chromosome could be isolated except for chromosomes 1 and 2 and chromosomes 9 to 12, which were isolated in a group. Telomere length was correlated with the size of the corresponding chromosome. Concomitant relative telomeric repeat content analysis in each chromosome and terminal restriction fragment analysis using the whole genome revealed that the terminal restriction fragments of each chromosome were heterogenously distributed through the smear of the fragments. This is the first description of an association between telomere length and chromosome size.

Chromosomes↗

PubMed2002

The fucosylation index of serum alpha-fetoprotein as useful prognostic factor in patients with hepatocellular carcinoma in special reference to chronological changes.

Aim of this study was to establish fucosylation index (FI) of alpha-fetoprotein (AFP) before and after initial treatment as a useful prognostic factor in patients with hepatocellular carcinoma (HCC). One hundred ninety-seven patients with HCC from 1990 to 2000, in whom an increment of serum AFP concentrations more than 30 ng/ml was observed before treatment, were examined in the present study. Enrolled patients with HCC underwent transcatheter arterial embolization, chemoembolization, percutaneous ethanol injection and/or percutaneous microwave coagulation therapy. The current patients status was confirmed as of the end of March 2001. FI was determined by crossed immunoaffinoelectrophoresis in the presence of Lens culinaris agglutinin (LCA). FI of AFP was defined as the percentage of the LCA-reactive species in total AFP (same as L3 fraction). When the tentative discriminating line of FI was set at 18%, the mean survival rate in the HCC group, whose FI-1 (before treatment) was higher than 18% (high FI), was significantly lower than that in another HCC group, whose FI-1 was equal to or less than 18% (low FI) by the generalized Wilcoxon test and the log rank test (P<0.0001). There were statistical significant differences of survival rate when FI-2 (2 months after treatment) and FI-3 (at the time of HCC recurrence or 2 years after treatment in the case of no recurrence) were introduced in the same analysis. Additionally, statistical significant differences of survival rates were obtained between HCC groups with high and low FI-1 when the patient stage was limited to II, III, IVA or IVB. The HCC group, FI-1, FI-2 and FI-3 of which were persistently equal to or less than 18%, showed considerably better prognosis than the group, whose FI-1, FI-2 and FI-3 were persistently higher than 18%. The univariate analysis in the prognostic factor by the Cox's proportional hazards model showed that FI-1, FI-2 and FI-3 were independent prognostic factors. The present study indicates that measuring FI from the sera before and after the treatment serves as a new prognostic indicator and may improve prognostic estimates and appraisal of therapeutic outcome in patients with HCC.

Journal Article↗

PubMed2002

Remote development of hepatocellular carcinoma in patients with liver cirrhosis type B serologically cured for HBs antigenemia with long-standing normalization of ALT values.

In this report, we examine two patients with chronic hepatitis B virus (HBV) infection that had been diagnosed as precirrhosis or liver cirrhosis more than a decade previously. These patients had been cleared of HBsAg and had developed anti-HBs at a later time, yet hepatocellular carcinoma (HCC) eventually occurred. Both patients had been found negative for HBV DNA, using sensitive methods. Interestingly, a nontumor specimen of the liver obtained at surgical resection showed a marked reduction of fibrosis when compared to the histology observed when the patient was diagnosed as precirrhosis. Our findings suggest that the fibrosis from liver cirrhosis had been absorbed to a large extent during the long-term absence of active viremia and the normalization of alanine aminotransferase (ALT) levels. However, the cancer-prone biological characteristics of liver cirrhosis remained. Thus, patients with liver cirrhosis due to past chronic hepatitis B should be monitored carefully for the development of HCC even if HBV infection has been serologically resolved.

Adult↗

PubMed2002

In situ localization and in vitro expression of osteoblast/osteocyte factor 45 mRNA during bone cell differentiation.

The in situ localization of osteoblast/osteocyte factor 45 (OF45) mRNA during bone formation has been examined in the rat mandible from embryonic day 14 (E14) up to postnatal 90-day-old Wistar rats. Gene expression was also examined during cell culture not only in primary rat osteoblast-like cells but also in two clonal rat osteoblastic cell lines with different stages of differentiation, ROB-C26 (C26) and ROB-C20 (C20) using Northern blot analysis. The C26 cell is a potential osteoblast precursor cell line, whereas the C20 cell is a more differentiated osteoblastic cell line. At E15 osteoblast precursor cells differentiated into a group of osteoblasts, some of which expressed the majority of non-collagenous proteins, whereas no expression of OF45 was observed in these cells. Intercellular matrices surrounded by osteoblasts were mineralized at E16. Subsequently, the number of osteoblasts differentiated from osteoblast precursor cells was increased in association with bone formation. At E17, the first expression of OF45 mRNA was observed only in a minority of mature osteoblasts attached to the bone matrix, but not in the rest of less mature osteoblasts. At E20, concomitant with the appearance of osteocytes, OF45 mRNA expression was observed not only in more differentiated osteoblasts that were encapsulated partly by bone matrix but also in osteocytes. Subsequently, osteocytes increased progressively in number and sustained OF45 mRNA expression in up to 90-day-old rats. Northern blot analysis of the cultured cells with or without dexamethasone treatment revealed that the gene expression of OF45 correlated well with the increased cell differentiation. These results indicate that OF45 mRNA is transiently expressed by mature osteoblasts and subsequently expressed by osteocytes throughout ossification in the skeleton and this protein represents an important marker of the osteocyte phenotype and most likely participates in regulating osteocyte function.

Animals↗

PubMedDate not supplied

Gene expression and immunohistochemical localization of osteonectin in association with early bone formation in the developing mandible.

We have compared the expression of osteonectin with that of osteocalcin and bone sialoprotein during bone formation in the rat mandible, using in situ hybridization and immunohistochemistry. Expression of osteonectin, osteocalcin and bone sialoprotein mRNAs were first observed in newly differentiated osteoblasts of the developing mandible at embryonic day 15 (E15) and subsequently increased with the number of osteoblasts through E20. Definitive osteonectin immunostaining was observed in newly differentiated osteoblasts, but not in the intercellular unmineralized matrix. Immunostaining for osteocalcin and bone sialoprotein was visible in osteoblasts and unmineralized matrix. Concomitant with the initiation of matrix mineralization at E16, mineralized bone matrix showed osteocalcin and bone sialoprotein immunostaining, but lacked osteonectin immunostaining. The same staining profile was observed during subsequent phases of bone formation at E17-20. However, sequential demineralization with ethanolic trimethylammonium EDTA and protease digestion of tissue sections demonstrated prominent osteonectin immunostaining of the mineralized bone matrix. Western blot analysis of osteonectin in extracts of fresh specimens at E18 and 20 revealed that an EDTA extract contains osteonectin having M, approximately 50 kDa. These results indicate that newly differentiated osteoblasts synthesize and secrete osteonectin, which is mainly incorporated into the mineralized bone matrix and becomes a specific component of developing manibula of foetal rats.

Animals↗