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H Sasaki

Publications and source records attributed to H Sasaki.

At least 163 records · Page 9Linked to original sources
PubMed2001

Allele-specific detection of nascent transcripts by fluorescence in situ hybridization reveals temporal and culture-induced changes in Igf2 imprinting during pre-implantation mouse development.

BACKGROUND: Genomic imprinting causes parental-origin-specific monoallelic transcription of a subset of mammalian genes in the embryo and adult. There is conflicting evidence, however, for the monoallelic transcription of some imprinted genes, such as Igf2, in pre-implantation embryos. RESULTS: We have developed an allele-specific fluorescence in situ hybridization method which involves a pair of oligonucleotide probes designed to detect an intronic polymorphism. The method, called ASO-RNA-FISH, enabled us to distinguish allelic nascent Igf2 transcripts in the cell nuclei of early mouse embryos, avoiding signals from the stored oocyte-specific transcripts. Igf2 transcription was first detectable in two-cell embryos, and biallelic transcription was predominant up to the morula stage. Then, the maternal allele became silenced during the blastocyst stage. When embryos were cultured in vitro, however, a strong bias to maternal transcription was observed up to the morula stage. CONCLUSION: ASO-RNA-FISH revealed that a transition of Igf2 from biallelic to monoallelic transcription occurs in the blastocyst stage. This developmental regulation was modified temporarily by in vitro culture, suggesting a possible link between altered imprinting and abnormalities of the foetuses experienced in vitro culture. ASO-RNA-FISH is therefore a powerful technique for the study of allele-specific gene expression.

Alleles↗
PubMed2001

Probe design optimization for a high-resolution scattering-type scanning near-field optical microscope.

UNLABELLED: The scattering-type scanning near-field optical microscope (SNOM) has a probe with a sharp tip for use in high resolution imaging. As sharp a tip as possible is generally considered ideal for the observations, but actually, a sharp tip does not always provide a high resolution SNOM image. We numerically examined the scattering property of the SNOM probe by the three dimensional finite difference time domain METHOD: In this paper, we show the criterion for the ideal scattering probe which satisfies the simple relation between radius and taper angle of the tip.

Journal Article↗
PubMed2001

Cytokeratin subtypes in biliary atresia: immunohistochemical study.

The etiology of biliary atresia (BA) remains unknown, but ductal-plate malformation and insufficient ductal-plate remodeling have been suggested to play important roles, so it is beneficial to examine the maturation and differentiation of bile ducts in BA. Different epithelial types are characterized by the expression of specific cytokeratin (CK) subtypes. CK can therefore serve as a 'lineage marker' of epithelial cells. CK subtypes have not been previously examined in BA. In this study, we examined the maturation of bile-duct cells in BA (n = 45) using immunohistochemistry of CK subtypes, with mouse monoclonal antibodies to CAM5.2, and CK subtypes 7, 8, 13, 14, 17, 19 and 20. We then compared these findings with pediatric non-BA (n = 11) and fetal (n = 21) liver. We semiquantitatively evaluated the findings using a H score method. In the fetal liver, immunoreactivity for CAM5.2, CK-7, CK-8 and CK-19 was detected in bile-duct cells, and CAM5.2 and CK-8 immunoreactivity was also detected in hepatocytes. The distribution of these CK subtypes was the same in fetal, pediatric non-BA and BA liver. However, CK-7 immunoreactivity was markedly weaker in bile ducts of fetal (H scores: ductal plate 0 +/- 0; remodeling 9.5 +/- 40.3; remodeled 37.3 +/- 60.8) and BA (H score: 200.9 +/- 55.3) liver compared to non-BA liver (H score: 251.1 +/- 33.5). In addition, CK-20 was detected in the bile ducts of the fetal and BA liver, but not in non-BA liver. These findings suggest that the expression patterns of CK subtypes in bile-duct cells in BA are similar to that in developing bile-duct cells, which is indicative of bile-duct cell immaturity.

Bile Ducts, Extrahepatic↗
PubMed2001

E-cadherin, alpha-catenin and beta-catenin in biliary atresia: correlation with apoptosis and cell cycle.

Biliary atresia (BA) is the most common cause of obstructive jaundice in infancy. Although the etiology of BA remains unknown, the ductal plate malformation has been considered to play an important role in the development of BA. Cell-cell adhesion has long been recognized as one of the most important processes in organogenesis. E-cadherin is involved in cell-cell adhesion, together with the catenins. Abnormalities of E-cadherin and associated catenins have not been examined in detail in the liver with BA. We therefore examined immunolocalization of E-cadherin and alpha- and beta-catenins in the BA liver (n = 45) and compared the findings with those in non-BA (n = 11) and fetal liver (n = 21). We semiquantitatively evaluated the findings using H score, which were generated according to the percentage of immunopositive cells and their immunointensity. We also examined mRNA localization of E-cadherin using mRNA in situ hybridization. We then studied the correlation of E-cadherin immunoreactivity with apoptotic cells, and cyclin-dependent kinase inhibitor p27Kip1 immunolocalization of bile duct cells in BA liver (n = 10) and fetal liver (n = 10). In fetal liver, H score of E-cadherin, but not of alpha- and beta-catenins, was significantly lower in the remodeling stage than in the ductal plate (P = 0.0034) and remodeled stages (P = 0.0024). In addition, the H score of E-cadherin, but not alpha- and beta-catenin, in bile duct cells was significantly lower in BA liver than in non-BA liver (P = 0.0132). E-cadherin mRNA hybridization signals were relatively conserved in bile duct cells of BA liver, but decreased in remodeling ductal plate cells of fetal liver. An inverse correlation was detected between the H score of E-cadherin and the TUNEL labeling index (LI) in both fetal and BA liver. In contrast, a positive correlation was detected between the H score of E-cadherin and p27 LI in both fetal and BA liver. These findings suggest that impaired expression of E-cadherin in bile ducts may play an important role in the biological features of BA, possibly associated with cell cycle and apoptosis.

Apoptosis↗
PubMed2001

Interventions to prevent pneumonia among older adults.

Pneumonia is a common cause of death in older people. Antimicrobial drugs do not prevent pneumonia and, because of increasingly resistant organisms, their value in curing infection will become more limited. Establishing new strategies to prevent pneumonia through consideration of the mechanisms of this devastating illness is essential. The purpose of this review is to discuss how pneumonia develops in older people and to suggest preventive strategies that may reduce the incidence of pneumonia among older adults. Aspiration of oropharyngeal bacterial pathogens to the lower respiratory tract is one of the most important risk factors for pneumonia; impairments in swallowing and cough reflexes among older adults, e.g., related to cerebrovascular disease, increase the risk for the development of pneumonia. Thus, strategies to reduce the volumes and pathogenicity of aspirated material should be pursued. For example, since both swallowing and cough reflexes are mediated by endogenous substance P, pharmacologic therapy using angiotensin-converting enzyme inhibitors, which decrease substance P catabolism, may improve both reflexes and result in the lowering of the risk of pneumonia. Similarly, since the production of substance P is regulated by dopaminergic neurons in the cerebral basal ganglia, treatment with dopamine analogs or potentiating drugs such as amantadine (and, of course, prevention of cerebral vascular disease, which can result in basal ganglia strokes) should affect the incidence of pneumonia. The purpose of this review is to consider promising pharmacologic treatments as methods of preventing pneumonia in older adults and to review other proven strategies, e.g., infection control and cerebrovascular disease prevention that will lessen the incidence of pneumonia.

Aged↗
PubMed2001

The renal metabolism of insulin: urinary insulin excretion in patients with mutant insulin syndrome (insulin Wakayama).

Many studies have shown that the kidney plays an important role in the metabolism of many proteins and small peptides. To understand insulin handling in the kidney, we examined urinary insulin excretion under several conditions in patients with mutant insulin syndrome (MIS; insulin Wakayama). Urinary excretion of insulin was studied using high-performance liquid chromatography analysis in patients with MIS. In these patients, most of the insulin extracted from a 24-hour urine collection and from urine collected after stimulation of insulin secretion by glucose or glucagon was normal insulin, whereas 90% of serum insulin is structurally abnormal (Leu-A3 insulin). On the other hand, arginine, which is known as an inhibitor of renal tubular reabsorption, increased urinary excretion of Leu-A3 insulin. The ratio of Leu-A3 and normal insulin in urine after arginine was similar to that in serum. A large amount of Leu-A3 insulin is excreted in urine when reabsorption of insulin at renal tubules is inhibited by arginine. These data indicate that normal and Leu-A3 insulin are filtered through the glomerulus with relatively little restriction. Using the fact that basal urine has a high concentration of normal insulin and an extremely low concentration of Leu-A3 insulin, which has less receptor-binding affinity, we speculated some possibilities. One possibility is that both forms of insulin are reabsorbed by the tubular cells, but with different efficiencies. Leu-A3 insulin absorption in more complete, and this suggests differences in the uptake pathways that may account for the differences in response to arginine infusions. Another possibility is that only normal insulin is secreted from tubules into urine which is mediated by receptors. Our results provide new insight into renal metabolism of insulin and showed that MIS is a useful model for studying it.

Adult↗
PubMed2001

[Characteristics and frequency of cortical cataracts at an early stage (Reykjavik Eye Study in Iceland)].

BACKGROUND: The frequency and characteristics of cortical cataract localization within a dilated pupillary area were investigated in a population-based cataract epidemiological survey performed in the city of Reykjavik in Iceland. MATERIALS AND METHODS: Among 1045 randomly selected individuals, the right eyes of 277 persons with mild cortical lens opacification (Grade I) were selected for our study. The localization of cortical cataracts was examined using retroillumination images, which were divided into 56 circular and radial sections, and calculations were made of the percentages for each opacified area. A questionnaire was used to record the number of hours spent outdoors during week days, the time of the day and whether the subjects wore spectacles, sunglasses or hats when outside. RESULTS: The percentage of cortical opacification was significantly higher in the lower nasal quadrant than in all other quadrants (p < 0.05). Furthermore, the percentage of opacification localized in the lower nasal quadrant was higher in individuals with a longer history of outdoor activity than those without (p < 0.05). The percentage of opacification in individuals, who have had the habit of wearing sunglasses for outdoor activities lasting longer than half an hour during weekdays in their 20's and 30's was lower in all quadrants and statistically significantly lower in the upper temporal quadrant (p < 0.05) compared to those not wearing sunglasses. CONCLUSION: This suggests that wearing sunglasses is effective in preventing the development and/or progression of cortical cataracts.

Aged↗
PubMed2001

Acidic polysaccharides from rhizomes of Atractylodes lancea as protective principle in Candida-lnfected mice.

Prophylactic effects upon imunnosuppressed mice lethally infected by Candida albicans were examined in fractions prepared from a constituent herb of Juzen-taiho-to (TJ-48, Si-Quan-Da-Bu-Tang), rhizomes of Atractylodes lancea DC. The oral administration of water extract obtained from a residue after MeOH extraction of rhizomes significantly prolonged the survival period of the infected mice at a dose of 140 mg/kg/day compared with control mice, while the MeOH extract did not. In the crude polysaccharide fraction (F-2) obtained by EtOH precipitation of the water extract, a significant life-prolonging effect was observed by the administration of 70 mg/kg/day. F-2 was further fractionated, and the resulting strongly acidic polysaccharide fraction, F-2-2, had a protective effect at a dose of 17.5 mg/kg/day. This fraction mainly consisted of acidic pectic polysaccharides containing about 80% galacturonic acid. The protective activity of F-2-2 was lost by periodate oxidation, but not by protease digestion, suggesting that the polysaccharide component of F-2-2 plays a major role in the protective activity against Candida-infected mice.

Animals↗
PubMed2001

Insulin inhibits glucagon-induced glycogenolysis in perivenous hepatocytes specifically.

Hepatocytes form the hepatic acinus as the unit of microcirculation. Following the bloodstream, at least 2 different zones can be discerned: the periportal and perivenous zones. Two types of hepatocytes, periportal hepatocytes (PPHs) and perivenous hepatocytes (PVHs), have been thought to be functionally heterogeneous, with PPHs being predominantly gluconeogenic and PVHs being glycolytic. We therefore investigated the region-specific functional effects of insulin on glycogen synthesis, glycolysis, glycogenolysis, and gluconeogenesis in isolated PPHs and PVHs prepared by using the digitonin-collagenase method. Glycogen synthesis from 5 to 20 mmol/L glucose did not differ between the PPHs and PVHs of fed rats during 60 minutes of incubation. Lactate release induced by 5 to 20 mmol/L glucose was 3 times greater from PVHs than from PPHs (P <.01). The addition of insulin did not accelerate either glycogen synthesis or lactate release during 60 minutes of incubation. Insulin did not inhibit glucose release from gluconeogenic substrates with or without 0.2 nmol/L glucagon in either the PPHs or the PVHs of fasting rats. Insulin antagonized the 0.1 nmol/L glucagon-induced increase in glucose release from the PVHs of fed rats during 30 minutes of incubation (to 56.1% +/- 7.2%, P <.01) but not that from the PPHs (to 81.8% +/- 7.3%, P =.10). Thus the antagonizing effect was greater in PVHs than in PPHs (P <.01). Insulin binding did not differ between the PPHs and PVHs of fed rats. It was confirmed that PVHs are actually glycolytic. An acute metabolic effect of insulin was observed only in antagonizing glucagon-induced glycogenolysis in PVHs specifically. The specific effect of insulin on PVHs might depend on the differences in intracellular characteristics between PPHs and PVHs rather than hormone binding.

Animals↗
PubMed2001

Effects of hypoxia/reoxygenation on angiogenic factors and their tyrosine kinase receptors in the rat myocardium.

The process of angiogenesis is initiated primarily as a consequence of hypoxic stimulation at the cellular and molecular level. Although several angiogenic growth factors have been identified, at present a detailed understanding of the interplay among inducing stimuli, growth factors, and their respective molecular targets remains to be evaluated. Here we report the effects of progressively increasing durations of moderate hypoxia on the protein expression profiles and tissue distribution patterns of the vascular endothelial growth factor system and the angiopoietin/Tie system in the adult rat myocardium. The relative temporal trends of expression of the various components of these two systems, as well as apparent relationships between Flk-1 and angiopoietin-2 and between Flt-1 and Tie-1, suggest a probable sequence of involvement during myocardial angiogenesis, as proposed in our model. Such relationships may potentially be utilized in formulating strategies for sequential gene therapy to achieve clinically relevant myocardial angiogenesis.

Angiopoietin-2↗
PubMed2001

Expression of the cdc25B mRNA correlated with that of N-myc in neuroblastoma.

BACKGROUND: Neuroblastoma is one of the most common solid tumors in early childhood. Overexpression of the proto-oncogene N-myc has been reported to be correlated with more malignant course of the disease. cdc25B is reported to be a target of myc and elevated in several malignant cells and tissues. METHODS: Expression of cdc25B and N-myc messenger RNAs were evaluated by real-time reverse transcription polymerase chain reaction (RT-PCR) assay in 20 tumor samples from neuroblastoma using LightCycler. The data were analyzed with reference to clinicopathological factors. Immunohistochemistry for cdc25B was also performed. RESULTS: There was no significant difference in the cdc25B expression between patient groups according to age, gender and clinical stage. The cdc25B mRNA expression levels were significantly correlated with N-myc mRNA levels (y = -0.445 + 20.577x, p < 0.0001). CONCLUSION: We could not establish the clinical significance to determine the cdc25B mRNA level from neuroblastoma. However, we suggest that cdc25B may play an active role as a target of N-myc in neuroblastoma, although the biological function of cdc25B in neuroblastoma remains to be clarified.

Cell Cycle Proteins↗
PubMed2001

Expression of the protein gene product 9.5, PGP9.5, is correlated with T-status in non-small cell lung cancer.

BACKGROUND: In a tumor, increased deubiquitination of cyclins by a protein gene product gene, PGP9.5, could contribute to the uncontrolled growth of somatic cells that is a hallmark of cancer. We hypothesized that PGP9.5 may be expressed in tumors of patients with non-small cell lung cancer (NSCLC). METHODS: Expression of PGP9.5 messenger RNA was evaluated by reverse transcription polymerase chain reaction (RT-PCR) in 95 non-small cell lung carcinomas and adjacent histological normal lung samples. The data were analyzed with reference to clinicopathological factors. RESULTS: PGP9.5 transcripts were detected in 18 (12.8%) of the tumor samples, although some of paired normal lung samples showed very weak expression. There was no relationship between PGP9.5 gene expression and age, gender, N-status or pathological subtype. PGP9.5 gene was preferentially expressed in T3/T4 NSCLC (12/41, 29.3%) compared with T1/T2 NSCLC (6/54, 11.1%) (p = 0.0482). CONCLUSIONS: Although the PGP9.5 gene was not expressed in a majority of NSCLC tumors, we suggest that PGP9.5 may correlate with tumor invasion or progression of NSCLC.

Adult↗
PubMed2001

Follicular stage-dependent tumor necrosis factor alpha-induced hen granulosa cell integrin production and survival in the presence of transforming growth factor alpha in vitro.

The link between cell adhesion to extracellular matrix and integrin-mediated survival signals has been established in several physiological systems, and roles for the cytokines tumor necrosis factor alpha (TNF alpha) and transforming growth factor alpha (TGF alpha) have been suggested. TGF alpha stimulates fibronectin production in hen granulosa cells and is an important survival factor during follicular maturation. In contrast, the role of TNF alpha and its possible interaction with TGF alpha in the regulation of granulosa cell fate (death versus survival) during ovarian follicular development have not been fully elucidated. The object of the current study was to determine if TNF alpha and TGF alpha interact in the regulation of hen granulosa cell fibronectin and integrin content in the context of cell death and survival during follicular development. TGF alpha (0.1 or 10 ng/ml), but not TNF alpha (0.1 or 10 ng/ml), increased both cellular and secreted fibronectin content in granulosa cell cultures of F5,6 but not F1 follicles. The expression of integrin beta(3) subunit was also stimulated by TGF alpha in a follicular stage-dependent manner, and culture of F5,6 granulosa cells with TNF alpha in the presence of maximal stimulatory concentrations of TGF alpha potentiated this response. TGF alpha increased both F5,6 and F1 granulosa cell [(3)H]thymidine incorporation but not 3-(4,5-dimethylthiazol-2-yl)3,5-diphenyl tetrazolium bromide (MTT) metabolism. Although TNF alpha had no effect on [(3)H]thymidine incorporation irrespective of the presence of the growth factor, MTT metabolism was higher in F5,6 granulosa cells cultured for 24 h with both TNF alpha and TGF alpha than with either cytokine alone. Incubation of F5,6 granulosa cells for 48 and 72 h resulted in a TGF alpha-inhibited loss of cellular adhesion and detachment of granulosa cells from the growth surface. Although TNF alpha alone had no effect on cell morphology, it facilitated the reorganization of the granulosa cells into multicellular follicle-like structures in the presence of the growth factor. DNA degradation significantly increased between 0 and 72 h of culture in the absence of the cytokine but was suppressed by the addition of TGF alpha but not of TNF alpha. However, fluorometric analysis indicated that the primary type of cell death exhibited by F5,6 granulosa cells during extended culture and attenuated by the presence of TNF alpha and TGF alpha was necrosis and not apoptosis. The current study demonstrates that TNF alpha and TGF alpha interact in the regulation of granulosa cell integrin content and cell survival in vitro in a follicular stage-dependent manner. These findings suggest that follicular development is accompanied by a change in the intraovarian role of TNF alpha; it is atretogenic prior to follicular selection but prevents follicular demise during preovulatory growth.

Acridine Orange↗
PubMed2001

Antitumor activity, optimum administration method and pharmacokinetics of 13,14-dihydro-15-deoxy-deoxy-Delta7 -prostaglandin A1 methyl ester (TEI-9826) integrated in lipid microspheres (Lipo TEI-9826).

13,14-Dihydro-15-deoxy-Delta7-prostaglandin A1 methyl ester (TEI-9826), an antitumor prostaglandin analog, is a candidate for clinical trial. In the present study, we examined its biological stability in vitro, antitumor activity in vitro and in vivo, and pharmacokinetics. Although TEI-9826 was rapidly hydrolyzed to the carboxylic acid form (TOK-4528), TOK-4528 as well as Delta12-prostaglandin J2 (PGJ2) were found to be stable in rat, mouse and human serum in vitro. TEI-9826 exhibited nearly identical or greater potential antitumor activity compared to Delta12-PGJ2 and Delta7-PGA1 in vitro against Colon26 tumor cells. Further evaluation of TEI-9826 using the 38 human cancer cell lines panel and COMPARE analysis suggested that its mode of action is quite different from other anticancer agents that are currently used. TEI-9826 was integrated into lipid microspheres (Lipo TEI-9826) for dosing. Growth inhibition by Lipo TEI-9826 against Colon26 tumor inoculated s.c. in mice depended on administration route, i.e. at 80 mg/kg, no growth suppressive effect was observed for daily bolus i.v., but significant growth suppressive effect was observed for daily i.p., daily s.c. every other day s.c. and 4 times a day continuous (5 min) i.v. These tumor growth-suppressive effects were cytostatic and the tumor started to regrow at the end or a few days after the end of administration. The pharmacokinetic study suggested that maintaining the blood level of TEI-9826 and/or TOK-4528 was essential for their antitumor effects. These results show that continuous i.v. infusion might be the most suitable administration method of Lipo TEI-9826 for clinical trial.

Animals↗