Biomedical subjects

H Sasaki

Publications and source records attributed to H Sasaki.

At least 127 records · Page 7Linked to original sources

PubMed2001

Meiotic instability of the CAG repeats in the SCA6/CACNA1A gene in two Japanese SCA6 families.

Intergenerational stability of the CAG repeat number has been considered to be a specific molecular feature of SCA6 compared with other CAG repeat diseases. Nevertheless, we showed meiotic instability of the CAG repeats in the SCA6/CACNL1A gene in two Japanese SCA6 families, including de novo expansion. In one family, the CAG20 allele expanded to the CAG26 one during paternal transmission, and in the other family, the CAG19 allele expanded to the CAG20 one during maternal transmission. Although it is controversial as to whether the CAG20 allele is pathological or not, this is the first case of haplotype analysis-proven de novo expansion in SCA6, confirming the derivation of an expanded allele from one normal allele. We should carefully follow up the individuals carrying the CAG20 allele in our family who show normal neurological and radiological findings at present.

Adult↗

PubMed2001

Epigenetic mark sequence of the H19 gene in human sperm.

We have investigated the epigenetic mark in the human H19 gene. The H19 promoter is methylation-free in human sperm, but it is methylated in the paternally derived allele of most adult tissues. Consequently, the H19 gene is exclusively transcribed from the maternal allele. It was demonstrated that the differentially methylated region (DMR) located 2 kb upstream from mouse H19 is essential for the imprinting of H19. A 39 bp sequence in DMR has a high degree of similarity between humans, mice and rats. The highly conserved 15 bp core region of the consensus sequence contains four methylatable sites, and thus has been proposed as a potential imprinting mark region. In this study, fine epigenetic sequencing analysis was performed on the sperm DNA in comparison with other adult organs. Interestingly, the conserved sequence of the potential mark region was methylated in almost all the sperm genomes analyzed. Furthermore, the single dinucleotide CpG, whose methylation affects the accessibility of the element to CTCF, was methylated in the conserved core in the human sperm. These results suggest that the human core sequences may act as an imprinting center in the reciprocal monoallelic expression of H19.

Adult↗

PubMed2001

Expression of DNA methyltransferases DNMT1, 3A, and 3B in normal hematopoiesis and in acute and chronic myelogenous leukemia.

Aberrant hypermethylation of tumor suppressor genes plays an important role in the development of many tumors. Recently identified new DNA methyltransferase (DNMT) genes, DNMT3A and DNMT3B, code for de novo methyltransferases. To determine the roles of DNMT3A, DNMT3B, as well as DNMT1, in the development of leukemia, competitive polymerase chain reaction (PCR) assays were performed and the expression levels of DNMTs were measured in normal hematopoiesis, 33 cases of acute myelogenous leukemia (AML), and 17 cases of chronic myelogenous leukemia (CML). All genes were constitutively expressed, although at different levels, in T lymphocytes, monocytes, neutrophils, and normal bone marrow cells. Interestingly, DNMT3B was expressed at high levels in CD34(+) bone marrow cells but down-regulated in differentiated cells. In AML, 5.3-, 4.4-, and 11.7-fold mean increases were seen in the levels of DNMT1, 3A, and 3B, respectively, compared with the control bone marrow cells. Although CML cells in the chronic phase did not show significant changes, cells in the acute phase showed 3.2-, 4.5-, and 3.4-fold mean increases in the levels of DNMT1, 3A, and 3B, respectively. Using methylation-specific PCR, it was observed that the p15(INAK4B) gene, a cell cycle regulator, was methylated in 24 of 33 (72%) cases of AML. Furthermore, AML cells with methylated p15(INAK4B) tended to express higher levels of DNMT1 and 3B. In conclusion, DNMTs were substantially overexpressed in leukemia cells in a leukemia type- and stage-specific manner. Up-regulated DNMTs may contribute to the pathogenesis of leukemia by inducing aberrant regional hypermethylation. (Blood. 2001;97:1172-1179)

Acute Disease↗

PubMed2001

Development of spectral colour banding in cytogenetic analysis.

We developed a novel chromosome banding technique-spectral colour banding (SCAN). With this technique we displayed a multicolour banding pattern that almost entirely correlated with the corresponding G-banding pattern. With SCAN analysis we could identify the chromosome-band origin of double minute chromosomes in gastric cancer. Our preliminary use of this technique suggests that it has significant clinical applications for cytogenetic analysis.

Carcinoma, Signet Ring Cell↗

PubMed2001

Functional annotation of a full-length mouse cDNA collection.

The RIKEN Mouse Gene Encyclopaedia Project, a systematic approach to determining the full coding potential of the mouse genome, involves collection and sequencing of full-length complementary DNAs and physical mapping of the corresponding genes to the mouse genome. We organized an international functional annotation meeting (FANTOM) to annotate the first 21,076 cDNAs to be analysed in this project. Here we describe the first RIKEN clone collection, which is one of the largest described for any organism. Analysis of these cDNAs extends known gene families and identifies new ones.

Animals↗

PubMed2001

Diagnostic significance of tau protein in cerebrospinal fluid from patients with corticobasal degeneration or progressive supranuclear palsy.

Distinguishing corticobasal degeneration (CBD) from progressive supranuclear palsy (PSP) is clinically and pathologically difficult, and a useful biological marker to discriminative these two diseases has been a subject of clinical interest. In the present study, we assessed tau protein levels in cerebrospinal fluids by sandwich ELISA to distinguish CBD from PSP. The subjects consisted of 27 cases of CBD, 30 cases of PSP, and 36 healthy controls (CTL). The tau values in CBD were significantly higher than those in PSP (P<0.001) and those in CTL (P<0.001). The assay of CSF tau provided diagnostic sensitivity of 81.5% and specificity of 80.0% between CBD and PSP according to receiver-operating characteristic (ROC) curve analysis. When values were compared separately with respect to stage of the disease, differences in the values for moderate CBD vs. moderate PSP had the greatest significance (P<0.001 sensitivity 92.3%, specificity 100.0%), followed by cases of mild CBD and PSP (P<0.005, sensitivity 100.0%, specificity 87.5%). The values in severe CBD and PSP were not significantly different (P=0.07, sensitivity 100%, specificity 75.0%). Using data obtained from a larger number of disease cases, we confirmed our previous findings that tau protein levels in cerebrospinal fluids in patients with CBD are significantly higher than those in patients with PSP. Because tau protein levels in cerebrospinal fluids are significantly higher in early CBD cases than in early PSP cases, measurement of tau protein levels in cerberospinal fluids may be useful for the differential diagnosis of early CBD from early PSP.

Aged↗

PubMed2001

Absence of endothelial cells, central necrosis, and fibrosis are associated with aggressive inflammatory breast cancer.

We recently established a new human inflammatory breast cancer (IBC) xenograft (WIBC-9) originating from a patient with IBC. The graft was transplantable in BALB/c nude and severe combined immunodeficient (SCID) mice. WIBC-9 was frequently accompanied by lung metastasis and exhibited erythema of the overlying skin, reflecting its human counterpart. Histological study of the original tumor and WIBC-9 revealed invasive ductal carcinoma with a hypervascular structure of solid nests and marked lymphatic permeation in the overlying dermis. In the central part of the solid nests, absence of endothelial cells, central necrosis, and fibrosis were observed. In vitro, WIBC-9 formed tube-like structures and loops, reflecting its in vivo feature and its human counterpart. WIBC-9 exhibited aneuploidy, ErbB-2 gene amplification, and an absence of estrogen receptor and progesterone receptor, which is consistent with IBC. Comparative studies of WIBC-9, three established non-IBC xenografts, and a human breast cancer cell line (SK-BR3) by reverse transcription-PCR, ELISA, and immunohistochemistry indicated that certain human genes (interleukin 8, vascular epidermal growth factor, basic fibroblast growth factor, angiopoietin 13, Flt-1, Tie-2, and Tie-1) and certain murine genes (integrin alpha(v)beta3, flt-1, tie-2, vascular epidermal growth factor, and CD31) were overexpressed in exposure to tumor cells. The molecular basis and these unique histological features may be associated with aggressive IBC on angiogenic and nonangiogenic pathways.

Angiogenesis Inducing Agents↗

PubMed2001

Effect of oxygen on induction of the cystine transporter by bacterial lipopolysaccharide in mouse peritoneal macrophages.

Amino acid transport in mouse peritoneal macrophages is mediated by several membrane carriers with different substrate specificity and sensitivity to environmental stimuli. We reported previously that transport activities of cystine and arginine in the macrophages were induced markedly by low concentrations of bacterial lipopolysaccharide (LPS). It is known that a variety of macrophage functions are affected by ambient oxygen tension. In this study, we have investigated the effects of oxygen on the induction of amino acid transport activity by LPS and found that the induction of cystine, but not arginine, transport activity was dependent on the ambient oxygen tension. When the macrophages were cultured with 2% O(2) in the presence of 1 ng/ml LPS, induction of cystine transport activity was reduced by approximately 70% compared with cells cultured under normoxic conditions. In macrophages, transport of cystine is mediated by a Na(+)-independent anionic amino acid transporter named system x(c)(-). System x(c)(-) is composed of two protein components, xCT and 4F2hc, and the expression of xCT was closely correlated with system x(c)(-) activity. A putative NF-kappaB binding site was found in the 5'-flanking region of the xCT gene, but the enhanced expression of xCT by LPS and oxygen was not mediated by NF-kappaB binding. An increase in intracellular GSH in macrophages paralleled induction of xCT, but not gamma-glutamylcysteine synthetase. These results suggest the importance of system x(c)(-) in antioxidant defense in macrophages exposed to LPS and oxidative stress.

Amino Acids↗

PubMed2001

Large-scale, multicenter study of cerebrospinal fluid tau protein phosphorylated at serine 199 for the antemortem diagnosis of Alzheimer's disease.

We surveyed a total of 570 cerebrospinal fluid (CSF) samples from a variety of diseases, including Alzheimer's disease (AD; n = 236), non-AD-demented and nondemented diseases (n = 239), and normal controls (n = 95) to quantitate levels of tau protein phosphorylated at serine 199 (CSF/phospho-tau199) by a recently established sandwich ELISA. The CSF/phospho-tau199 levels in the AD group were significantly elevated compared to those in all the other non-AD groups. Receiver operating characteristics curves showed that the diagnostic sensitivity and specificity for the AD group vs all the other non-AD groups using the CSF/phospho-tau199 were 85.2% and 85.0%, respectively. Furthermore, there was a significant positive correlation between CSF/phospho-tau199 and CSF/total-tau levels in the AD group. Elevated CSF/phospho-tau199 in the AD group was noted irrespective of age, gender, dementia severity, and number of apolipoprotein E4 alleles. Thus, we suggest that CSF/phospho-tau199 may be a novel and logical biomarker in supporting antemortem diagnosis of AD.

Aged↗

PubMed2001

Ocular absorption behavior of palmitoyl tilisolol, an amphiphilic prodrug of tilisolol, for ocular drug delivery.

The objective of this study was to examine the ocular absorption behavior of an amphiphilic prodrug after instillation onto the cornea of rabbits. A micellar solution of O-palmitoyl tilisolol (PalTL), an amphiphilic prodrug, was prepared. After instillation of tilisolol (TL) and PalTL, the drug concentrations in the tear fluid, cornea, aqueous humor, iris-ciliary body, vitreous body, and blood were measured. In addition, in situ ocular absorption behavior was also evaluated. After instillation of TL, the concentration of TL in the tear fluid quickly decreased. After instillation of PalTL, prolonged retention and high concentrations of PalTL in tear fluid and the cornea were observed. In addition, more prolonged retention of the TL concentration after instillation of PalTL than after instillation of TL was observed in the cornea, aqueous humor, and iris-ciliary body. In situ experiments demonstrated that PalTL was mainly absorbed by the corneal route and the improvement effects of PalTL under in vivo conditions was due to an enhanced transit time of PalTL in ocular tissues. PalTL, an amphiphilic prodrug, exhibited increased retention in the precorneal area compared with the parent drug, TL, resulted in improved ocular absorption of the parent drug.

Absorption↗

PubMed2001

Effects of Dai-kenchu-to, a herbal medicine, on uterine and intestinal motility.

The effects of both Dai-kenchu-to and PGF(2alpha) on intestinal and uterine motility were studied in anaesthetized rabbits with force transducers implanted in the jejunum, ileum and uterus. A single intraduodenal administration of Dai-kenchu-to (300 mg/kg) enhanced the intestinal motility but not the uterine motility. However, intravenous administration of PGF(2alpha) (20 microg/kg) enhanced both intestinal and uterine motility. The effects of Dai-kenchu-to on the spontaneous contraction and contractile response of the isolated rat uterine strips to oxytocin, PGF(2alpha) or ACh were also studied. Oral administration of Dai-kenchu-to at 300 mg/kg for one week had no effect on either the spontaneous contraction or the contractile response of the uterus. These results indicate that Dai-kenchu-to may exert stimulatory effects on intestinal motility, as PGF(2alpha), but has no effect on the uterine motility, suggesting a selective effect on the gastrointestinal tract. Hence, Dai-kenchu-to may be safer than PGF(2alpha) in the treatment of postoperative adhesive ileus in women. However, more studies are needed to determine whether Dai-kenchu-to could be administered to pregnant women.

Animals↗

PubMed2001

Cerebrospinal fluid amyloid beta(1-42) levels in the mild cognitive impairment stage of Alzheimer's disease.

Cerebrospinal fluid (CSF) levels of amyloid beta-protein ending at amino acid position 42 (CSF-A beta(1-42)) and CSF-tau levels were quantified by sandwich ELISAs in 19 patients with mild cognitive impairment (MCI) who eventually developed Alzheimer's disease (AD) on follow-up as well as in 15 age-matched normal controls and 54 AD patients at diverse stages of the disease. In the present study, the annual conversion rate was approximately 15%. The CSF-A beta(1-42) levels did not differ significantly between the normal control group and the MCI group, however, these values declined significantly once AD became clinically overt. In contrast to CSF-Abeta(1-42), CSF-tau levels were significantly increased in the MCI stage, and these values continued to be elevated thereafter, indicating that increased levels of CSF-tau may help in detecting MCI subjects who are predicted to develop AD. We propose that CSF-tau and CSF-A beta(1-42) must be used as two distinct biomarkers that should be applied appropriately in clinical settings.

Aged↗

PubMed2001

Hypoxia/reoxygenation promotes myocardial angiogenesis via an NF kappa B-dependent mechanism in a rat model of chronic myocardial infarction.

Therapeutic angiogenesis achieved either through the use of discreet angiogenic proteins or by gene therapy is fast emerging as a highly attractive treatment modality for ischemic heart disease. Herein we examine a novel method of stimulating myocardial angiogenesis by hypoxic preconditioning at both capillary and arteriolar levels, and the potential role of NF kappa B in mediating such a response. We also investigate the functional relevance of such treatment by assessing whether the induced neovascularization can help preserve left ventricular contractile functional reserve in the setting of developing heart failure secondary to myocardial infarction. Male Sprague-Dawley rats were randomly divided into eight groups: normoxia + sham surgery (NS), normoxia + permanent left anterior descending coronary artery (LAD) occlusion (NMI), hypoxic preconditioning + sham surgery (HS), hypoxic preconditioning + permanent LAD occlusion (HMI), PDTC (NF kappa B inhibitor) + hypoxic preconditioning + LAD occlusion (PHMI), PDTC+normoxia + LAD occlusion (PNMI), PDTC + hypoxic preconditioning + sham surgery (PHS) and PDTC + normoxia + sham surgery (PNS). Rats in the preconditioned groups were subjected to systemic hypoxemic hypoxic exposure (10+/-0.4% O2) for 4 h followed by a 24-h period of normoxic reoxygenation prior to undergoing LAD occlusion. Rats in the normoxia groups were time matched with the preconditioned group and maintained under normoxic conditions for the 28-h period prior to LAD occlusion. The HMI group displayed significant increases in capillary as well as arteriolar density after 2, 4 and 7 days post-operation compared to the NMI. Prior PDTC administration prevented such increases in the PHMI group and effectively abolished the pro-angiogenic effect of hypoxic preconditioning (HP). One week after sham surgery or LAD occlusion, rats underwent a pharmacological stress test with dobutamine in progressively increasing doses which revealed significantly elevated values of dp/dt(max) at each dose point in the HMI group compared to the NMI or PHMI groups. Hypoxic preconditioning also decreases endothelial cell injury as determined by the extent of endothelial cell apoptosis using anti-VWF factor labelling and TUNEL assay. The results suggest that HP stimulates myocardial angiogenesis via redox-regulated transcription factor, NF kappa B-dependent pathway to an extent sufficient to exert significant preservation of contractile functional reserve in a rat model of myocardial infarction progressing to heart failure.

Animals↗

PubMed2001

Clinical significance of matrix metalloproteinase-7 and Ets-1 gene expression in patients with lung cancer.

BACKGROUND: Matrix metalloproteinase-7 (MMP-7) is a member of the MMP family and has a wide variety of substrate spectra. Ets domain transcription factors are reported to play an important role in carcinoma invasion and metastasis. The regulatory role of Ets-1 has been shown in several MMPs. We have hypothesized that MMP-7 and Ets-1 mRNA levels could be predictors of the development and invasion of lung cancer. METHODS: The study included 73 lung cancer cases. The mRNA levels were quantified by real-time reverse transcription-polymerase chain reaction (RT-PCR) using a LightCycler. RESULTS: No significant difference in MMP-7 and Ets-1 mRNA levels was found among gender, age, and pathological subtype. The MMP-7 mRNA levels were elevated in tumor tissues from stage II-IV lung cancer (1.629 +/- 2.267) compared to those from stage I lung cancer (0.762 +/- 1.463) (P = 0.0290). There was a tendency toward higher MMP-7 mRNA expression levels in tumors with lymph node metastasis (1.728 +/- 2.432) compared to those without lymph node metastasis (1.141 +/- 1.838) (P = 0.1076). Thus, MMP-7 mRNA levels may serve as a marker of higher stages in lung cancer. No significant difference in Ets-1 mRNA levels was found among clinical stages and T-status. The Ets-1 mRNA levels were elevated in tumors from N2 patients (7.512 +/- 13.306) compared to those from N0 patients (2.525 +/- 4.719) (P = 0.0209). Ets-1 mRNA levels showed a positive correlation with MMP-7 expression (P = 0.0042). CONCLUSIONS: Using the LightCycler RT-PCR assay, the determination of MMP-7 and Ets-1 mRNA levels might provide a potential marker for advanced lung cancer. However, further studies and a longer follow-up are needed to confirm the impact of MMP-7 in the biological behavior of the tumor.

Adult↗

PubMed2001

Hybrid revascularization feasibility in minimally invasive direct coronary artery bypass grafting combined with percutaneous transluminal coronary angioplasty in patients with acute coronary syndrome and multivessel disease.

OBJECTIVES: We reviewed early and midterm outcome of 11 multivessel-disease acute coronary syndrome patients treated by hybrid revascularization, i.e., initial coronary angioplasty followed by minimally invasive direct coronary artery bypass grafting. We evaluated procedural efficacy and applicability. METHODS: Beginning in August 1997, hybrid revascularization was conducted in 11 multivessel-disease acute coronary syndrome patients--9 men and 2 women with a mean age of 70.3 +/- 9.3 years. Occlusion or stenosis of the target coronary artery was treated by interventional cardiologic techniques and minimally invasive direct coronary artery bypass grafting, and the early and midterm outcome evaluated. Coronary angiography was conducted in all cases at 2 weeks, 6 months, 1 and 3 years postoperatively to evaluate anastomosis and restenosis in treated coronary vessels. RESULTS: Initial intervention succeeded in patients with minimal residual stenosis. Subsequent minimally invasive direct coronary artery bypass grafting involved no complications. Coronary angiography early postoperatively, 6 months, 1 and 3 years later showed grafts patent without stenosis. Percutaneous transluminal coronary angioplasty was reconducted on restenotic lesions in 3 patients, 1 of whom required 3 procedures. CONCLUSIONS: Hybrid revascularization appears safe and effective in coronary revascularization, at least over the short term. Several patients underwent angioplasty for restenosis within 3 years after initial procedure. Overall acceptance of this hybrid method depends on long-term functional success of the 2 procedures. Its major limitation is restenosis of angioplasty sites and the need for repeat procedures.

Aged↗

PubMed2001

Autoantibody to gravin is expressed more strongly in younger and nonthymomatous patients with myasthenia gravis.

Gravin is expressed in several cell and tissue types as either 300 kDa doublet or 250 kDa proteolytic products. It is a cytoplasmic antigen that reacts with the serum of patients with myasthenia gravis (MG). Autoantibodies to gravin residues 1477-1781 are highly specific for MG. In the present study, we examined residues 1477-1781 in detail and found that residues 1542-1547 of gravin protein, which had sequence homology with the binding sequences of two protein A-kinase anchoring proteins, were highly reactive to MG serum. Antigravin antibody activities were stronger in younger and nonthymomatous patients. These findings suggest that antigravin antibody activities could be a useful prognostic factor and that the gravin antibody of MG may have a function which prevents the protein A-kinase binding pathway.

A Kinase Anchor Proteins↗

PubMed2001

Elevated serum vascular endothelial growth factor and basic fibroblast growth factor levels in patients with thymic epithelial neoplasms.

Neovascularization, an essential event for the growth of solid tumors, is regulated by a number of angiogenic factors, among which vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF), are considered to exert potent angiogenic activity. In this study, we investigated whether serum VEGF and bFGF levels could be predictors of the development and extension of thymic epithelial neoplasms. The subjects of this study were 37 patients with thymoma, 6 with thymic carcinoma, and 23 healthy volunteers. Serum samples were collected before clinical treatment. Serum VEGF levels were significantly (P < 0.05) elevated in the patients with thymic carcinoma (1,080 +/- 1,185pg/ml) compared with those in the healthy volunteers (407 +/- 589 microg/ml). Serum bFGF levels were also significantly (P < 0.05) elevated in the patients with thymic carcinoma (2740 +/- 631 pg/ml) compared with those in the healthy volunteers (1728 +/- 1,192 pg/ml). However, the serum VEGF and bFGF levels did not significantly differ between the patients with thymoma and the healthy volunteers. Serum VEGF and bFGF levels did not significantly differ according to the stage and pathological subtype of thymoma. Moreover, there was no correlation between the serum levels of VEGF and those of bFGF. Thus, while serum VEGF and bFGF levels may serve as markers for thymic epithelial tumors, it is unlikely that circulating VEGF and bFGF could be used as markers for assessing the progression of thymoma tumors.

Adult↗

PubMed2001

Expression of the prothymosin-a gene as a prognostic factor in lung cancer.

Prothymosin-alpha (PTalpha) is known to play a role in cell proliferation, and the PTalpha mRNA level may reflect the degree of proliferation of tumor cells. It has been reported that PTalpha mRNA levels are higher in human colon and liver cancer tissues than in the adjacent normal tissues. We examined the mRNA levels of PTalpha and c-myc in 20 lung cancers, using Bas 2500Mac systems. The PTalpha and c-myc mRNA levels in lung cancer tissues were higher than those in normal lung tissues; however, the PTalpha mRNA levels did not correlate with the stage or pathological subtype of the lung cancer and there was no correlation between the expression of PTalpha and c-myc. PTalpha mRNA overexpression in lung cancer was correlated with a poor prognosis.

Aged↗