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Biomedical subjects

K Maruyama

Publications and source records attributed to K Maruyama.

At least 163 records · Page 9Linked to original sources
PubMed1999

Determination of carbohydrate-deficient transferrin separated by lectin affinity chromatography for detecting chronic alcohol abuse.

Carbohydrate-deficient transferrin (CDT) has been established as a valuable biological marker for detecting chronic alcohol abuse. To improve the diagnostic efficiency, we studied new CDT determination procedures involving the use of lectin affinity chromatography with Allomyrina dichotoma agglutinin (allo A) and Trichosanthes japonica agglutinin I (TJA-I) to isolate the CDT isoforms CDT-allo A and CDT-TJA, respectively. These procedures, based on detection of the CDT-allo A and CDT-TJA isoforms in sera, showed high sensitivity (100% and 98%, respectively) and high specificity (93% and 85%, respectively). These results demonstrate that the new procedures involving the use of lectin affinity chromatography are more useful for isolating markers in the CDT test than the conventional charge-based separation method.

Alcoholism↗
PubMed1999

Frontal lobe neuronal injury correlates to altered function in FIV-infected cats.

Six cats infected intravenously at 8 weeks of age with feline immunodeficiency virus Maryland isolate (FIV-MD), were evaluated at 8 and 14 months of age (6 months and 12 months postinfection, respectively) with high spatial resolution proton magnetic resonance spectroscopy (MRS) of the frontal cortex. Two separate control cat groups were evaluated at 8 months and 16 months of age. Single voxel two-dimensional high-resolution proton magnetic resonance imaging was performed using the PRESS sequence by selecting a 0.125 ml volume of interest in the medial frontal cortex. A significant reduction in both N-acetylaspartate (NAA) and NAA: choline ratio was found in the FIV 14-month-old group compared with FIV 8-month-old cats, and to the respective age-matched control 16-month-old cats. A negative correlation between NAA and CD4 lymphocyte count was seen in the FIV-14 group only. This group of FIV cats also exhibited a higher proportion of quantitative electroencephalographic relative slow wave activity (RSWA) that correlated to lower NAA content in the frontal cortical voxel. Although peripheral blood proviral load increased over time of infection, no correlation was found between proviral blood or lymph node load and NAA values, CD4 lymphocyte counts, or frontal cortical RSWA. Thus, this study demonstrated that neurologic functional disruption of the frontal cortex correlated strongly with neuronal injury and/or loss in FIV-MD-infected cats independent of peripheral proviral load. The ability to define in vivo neurodegeneration further in this animal model helps in understanding the neuropathogenesis of lentivirus infection, and possibly, a means to follow progression and reversibility during the initial stages of brain infection as therapeutic agents are identified.

Animals↗
PubMed1999

Norbin, a neurite-outgrowth-related protein, is a cytosolic protein localized in the somatodendritic region of neurons and distributed prominently in dendritic outgrowth in Purkinje cells.

Distribution of norbin protein in rats was characterized by immunohistochemical study. It was distributed not only in whole brain but also in peripheral nervous system. The protein was localized in the somata, except for nuclei, and dendrites of neurons. Subcellular fractionation revealed that norbin is a cytosolic protein. Prominent distribution was observed in dendrites of dendritic outgrowth in Purkinje cells. Norbin should play a role in somatodendritic functions of neurons.

Animals↗
PubMed1999

Overexpression of myotonic dystrophy protein kinase in C2C12 myogenic culture involved in the expression of ferritin heavy chain and interleukin-1alpha mRNAs.

The specific function of myotonic dystrophy protein kinase (DMPK) is still not known. We found that overexpression of human DMPK in C2C12 myogenic culture induces the expression of ferritin heavy chain (FN-H) mRNA using differential display analysis. The quantity of FN-H mRNA was greater in the DMPK transfectant with five CTG triplet repeats in the 3'-untranslated region, while it was lower in the transfectant with 46 CTG repeats, over that of the control clone. We also investigated the quantity of interleukin 1-alpha (IL-1alpha) mRNA in each culture, due to the fact that this cytokine is able to induce FN-H expression, regardless of the concentration of free iron. Quantitative, competitive polymerase chain reaction (PCR) analysis revealed that the quantity of IL1-alpha mRNA is higher in the transfectant with five repeats, compared to the quantity of mRNA in the control clone; however, it is markedly lower in the clone with 46 repeats. These results suggest that overexpression of DMPK in C2C12 cultures may up-regulate IL-1alpha expression, resulting in the induction of FN-H expression. However, a large number of CTG repeats in the 3'-untranslated region of the DMPK gene may affect the pathway of IL-1alpha transcription, thereby resulting in decreased expression of FN-H.

Animals↗
PubMed1999

Single and nested polymerase chain reaction assays for the detection of Microsporidium seriolae (Microspora), the causative agent of 'Beko' disease in yellowtail Seriola quinqueradiata.

Single and nested polymerase chain reaction (PCR) assays were developed for the detection of the microsporidian parasite Microsporidium seriolae, which is responsible for emaciation and even death in farmed Japanese yellowtail. Extremely high rDNA identities exist between this parasite and other members of the as yet unclassified genus, necessitating the design of generic, rather than species-specific primer sets. The nested PCR was several orders of magnitude more sensitive than the standard single PCRs, with visible target product amplified from as little as 0.01 pg of parasite DNA (equivalent to that extracted from a single spore). The specificity of the assays was tested against a range of potential host fishes and 6 other microsporidians infecting either fish or the musculature of their hosts. Single PCRs were found to be specific to the target genus, but the nested PCR replicated rDNA from several different microsporidian genera, limiting its utility. This study highlights problems associated with the use of the rRNA gene for PCR assays of certain microsporidians, but nevertheless provides a rapid and sensitive means for the detection of pre-spore forms not possible by current staining methods. Consequently, these assays may be employed for further studies on the portals of entry, migration to the musculature and transmission of this economically important pathogen.

Animals↗
PubMed1999

Effects of the endothelin ET(A) receptor antagonist, TA-0201, on pulmonary arteries isolated from hypoxic rats.

To investigate the roles of endothelin-1 in the pathogenesis of hypoxic pulmonary hypertension, we studied the effects of a selective endothelin ET(A) receptor antagonist, TA-0201 (N-(6-(2-(5-Bromopyrimidin-2-yloxy) ethoxy)-5-(4-methylphenyl) pyrimidin-4-yl)-4-(2-hydroxy-1,1-dimethylethyl) benzensulfonamide sodium salt sesquihydrate), on helical strips of pulmonary arteries isolated from hypoxia-induced pulmonary hypertensive rats as compared with those of normoxic rats. Endothelin-1-induced maximum contractions were significantly inhibited by exposure to hypoxia in the pulmonary arterial strips, but not in the mesenteric arterial strips. The hypoxia also induced right ventricular hypertrophy in rats. Addition of TA-0201 to the bath inhibited the endothelin-1-induced contraction of pulmonary arterial strips isolated from hypoxic rats more effectively than in those of normoxic rats. Oral administration of TA-0201 to hypoxic rats inhibited the hypoxia-induced right ventricular hypertrophy, and decreased the maximum contractile response to endothelin-1 in pulmonary arterial strips isolated from these rats. Those inhibitory effects induced by the oral administration of TA-0201 were not observed in the pulmonary arteries from normoxic rats or in the mesenteric arteries from both hypoxic and normoxic rats. These results suggest that endothelin-1 has important pathophysiological roles in hypoxia-induced pulmonary hypertension, and that TA-0201 may inhibit the endothelin-l-induced contraction through a change in the function of endothelin ET(A) receptor as well as competitive inhibition for endothelin ET(A) receptor.

Animals↗
PubMed1999

Protective effects of bacteriophage on experimental Lactococcus garvieae infection in yellowtail.

The present study describes the in vitro and in vivo survival of Lactococcus garvieae bacteriophages and the potential of the phage for controlling experimental L. garvieae infection in yellowtail. Anti-L. garvieae phages persisted well in various physicochemical (water temperature, salinity, pH) and biological (feed, serum and alimentary tract extracts of yellowtail) conditions, except for low acidity. In the in vivo, the phage PLgY-16 was detected in the spleens of yellowtail until 24 h after intraperitoneal (i.p.) injection, or the phage was recovered from the intestine of yellowtail 3 h after the oral administration of phage-impregnated feed but undetectable 10 h later. Simultaneous administration of live L. garvieae and phage enhanced recovery of the phage from the spleen or intestine. The survival rate was much higher in yellowtail that received i.p. injection of the phage after i.p. challenge with L. garvieae, compared with that of control fish without phage injection. When fish were i.p. injected with phage at different hours after L. garvieae challenge, higher protective effects were demonstrated in fish that received phage treatment at the earlier time. Protection was also obtained in yellowtail receiving phage-impregnated feed, in which fish were challenged by an anal intubation with L. garvieae. Anal-intubated L. garvieae were detected constantly in the spleens of the control fish, while they were detected sporadically and disappeared from the phage-treated fish 48 h later. On the other hand, orally administered phage was detected at high plaque-forming units from the intestines and spleens of the phage-treated fish until 48 h later. These results indicate that intraperitoneally or orally administered anti-L. garvieae phage prevented fish from experimental L. garvieae infection, suggesting potential use of the phage for controlling the disease.

Administration, Oral↗
PubMed1999

Angiotensin II-induced transactivation of epidermal growth factor receptor regulates fibronectin and transforming growth factor-beta synthesis via transcriptional and posttranscriptional mechanisms.

The signaling cascade elicited by angiotensin II (Ang II) resembles that characteristic of a growth factor, and recent evidence indicates transactivation of epidermal growth factor receptor (EGF-R) by G protein-coupled receptors. Here, we report the involvement of EGF-R in Ang II-induced synthesis of fibronectin and transforming growth factor-beta (TGF-beta) in cardiac fibroblasts. Ang II stimulated fibronectin mRNA levels dose dependently, with a maximal increase (approximately 5-fold) observed after 12 hours of incubation. Fibronectin synthesis induced by Ang II or calcium ionophore was completely abolished by tyrosine kinase inhibitors and intracellular Ca2+ chelating agents. Ang II-induced fibronectin mRNA was not affected by protein kinase C inhibitors or protein kinase C depletion, whereas specific inhibition of EGF-R function by a dominant negative EGF-R mutant and tyrphostin AG1478 abolished induction of fibronectin mRNA. We isolated the rat fibronectin gene, including the 5'-flanking region, and found that the activator protein-1 (AP-1) binding site present in the promoter region was responsible for the Ang II responsiveness of this gene. A gel retardation assay revealed the binding of nuclear protein to the AP-1 site, which was supershifted with anti-c-fos and anti-c-jun but not anti-activating transcription factor (ATF)-2 antibodies. Conditioned medium from Ang II-treated cells contained TGF-beta bioactivity, and addition of neutralizing TGF-beta antibody modestly (46%) inhibited induction of fibronectin. Ang II-induced synthesis of TGF-beta was also abolished by inhibition of EGF-R function. The effect of TGF-beta was exerted by stabilizing fibronectin mRNA without affecting the promoter activity and required de novo protein synthesis. We concluded that Ang II-induced expression of fibronectin and TGF-beta is mediated by downstream signaling of EGF-R transactivated by Ca2+-dependent tyrosine kinase and that Ang II-induced fibronectin mRNA expression is regulated by 2 different mechanisms, which are transcriptional control by binding of the c-fos/c-jun complex to the AP-1 site and posttranscriptional control by mRNA stabilization due to autocrine or paracrine effects of TGF-beta. Thus, this study suggests that the action of Ang II on extracellular matrix formation should be interpreted in association with the EGF-R signaling cascade.

Angiotensin II↗
PubMed1999

Conservation of structure and cold-regulation of RNA-binding proteins in cyanobacteria: probable convergent evolution with eukaryotic glycine-rich RNA-binding proteins.

The rbp gene family of the cyanobacterium Anabaena variabilis strain M3 consists of eight members that encode small RNA-binding proteins containing a single RNA recognition motif (RRM). Similar genes are found in the genomes of Synechocystis sp. PCC6803, Helicobacter pylori and Treponema pallidum, but are absent from the other completely sequenced prokaryotic genomes. The expression of the rbp genes of Anabaena is induced by low temperature, with the exception of the rbpD gene. We found four stretches of conserved sequences in the 5'-untranslated region of the cyanobacterial rbp genes that are known to be induced by low temperature. The cold-regulated Rbp proteins contain a short C-terminal glycine-rich domain. In this respect, these proteins are similar to plant and mammalian glycine-rich RNA-binding proteins (GRPs), which also contain a single RRM domain with a C-terminal glycine-rich domain and are highly expressed at low temperature. Detailed phylogenetic analysis showed, however, that the cyanobacterial Rbp proteins and the eukaryotic GRPs do not belong to a single lineage, but that the glycine-rich domains are likely to have been added independently. The cold-regulation of both types of proteins is also likely to have evolved independently. Furthermore, the chloroplast RNA-binding proteins are not likely to have originated from the Rbp proteins of endosymbiont cyanobacterium, but are supposed to have diverged from the GRPs. These results suggest that the cyanobacterial Rbp proteins and the eukaryotic GRPs are similar in both structure and regulation, but that this apparent similarity has resulted from convergent evolution.

Amino Acid Sequence↗
PubMed1999

Overexpression of GLUT4 in mice causes up-regulation of UCP3 mRNA in skeletal muscle.

Mitochondrial uncoupling protein 3 (UCP3) is expressed in skeletal muscles. We have hypothesized that increased glucose flux in skeletal muscles may lead to increased UCP3 expression. Male transgenic mice harboring insulin-responsive glucose transporter (GLUT4) minigenes with differing lengths of 5'-flanking sequence (-3237, -2000, -1000 and -442 bp) express different levels of GLUT4 protein in various skeletal muscles. Expression of the GLUT4 transgenes caused an increase in UCP3 mRNA that paralleled the increase of GLUT4 protein in gastrocnemius muscle. The effects of increased intracellular GLUT4 level on the expression of UCP1, UCP2 and UCP3 were compared in several tissues of male 4 month-old mice harboring the -1000 GLUT4 minigene transgene. In the -1000 GLUT4 transgenic mice, expression of GLUT4 mRNA and protein in skeletal muscles, brown adipose tissue (BAT), and white adipose tissue (WAT) was increased by 1.4 to 4.0-fold. Compared with non-transgenic littermates, the -1000 GLUT4 mice exhibited about 4- and 1.8-fold increases of UCP3 mRNA in skeletal muscle and WAT, respectively, and a 38% decrease of UCP1 mRNA in BAT. The transgenic mice had a 16% increase in oxygen consumption and a 14% decrease in blood glucose and a 68% increase in blood lactate, but no change in FFA or beta-OHB levels. T3 and leptin concentrations were decreased in transgenic mice. Expression of UCP1 in BAT of the -442 GLUT4 mice, which did not overexpress GLUT4 in this tissue, was not altered. These findings indicate that overexpression of GLUT4 up-regulates UCP3 expression in skeletal muscle and down-regulates UCP1 expression in BAT, possibly by increasing the rate of glucose uptake into these tissues.

Adipose Tissue, Brown↗
PubMed1999

A core promoter and a frequent single-nucleotide polymorphism of the mismatch repair gene hMLH1.

The hMLH1 gene encodes a protein that is involved in the DNA mismatch repair system. The coding region of the hMLH1 gene has been known to be mutated in a subset of patients with hereditary nonpolyposis colorectal cancer (HNPCC). Our current research characterized the promoter region of the hMLH1 gene and searched for mutations correlating to HNPCC. Utilizing the oligo-capping method, major transcription start sites of the hMLH1 gene were mapped at two locations. The core promoter region of about 180 bp was determined by the luciferase assay of serial deletion mutants. Although we did not find any pathogenic mutation in the hMLH1 promoter region by PCR-SSCP, we found a single-nucleotide polymorphism at position -93 nt from the adenine residue of the start codon. By PCR-RFLP analysis with Pvu II for this polymorphism, we detected LOH in four tumors from three patients. An easy detection of this polymorphism with PCR-RFLP and high incidence ( approximately 50%) of informative cases make this polymorphism a suitable marker for the detection of hMLH1 allelic losses.

3T3 Cells↗
PubMed1999

Two short sequences have positive effects on the human p27Kip1 gene transcription.

The cyclin-dependent kinase (Cdk) inhibitor p27Kip1 plays an important role in the progression from G1 to S phase in the cell cycle. To study the activities of its promoter and other regulatory elements, we have cloned and characterized the 5'-flanking region of the human p27Kip1 gene. This region, about 3kb in length, is GC-rich and shares homology with that of the mouse p27Kip1 gene. Transcription start points (tsp) determined by the oligo-capping method are mapped in two regions, the cluster I (-479 to -403) and cluster II (-280 to -273). The cluster I was the primary functional site in transcription initiation. The luciferase activities of serial deletion mutants indicated that two short sequences (-581 to -557 and -556 to -526) had positive effects on transcription. The gel shift assay showed that factors in HeLa nuclear extract bound to these sequences. Sp1 was the major binding factor to the sequence of -556 to -526, wheres yet unidentified positive factors bound to the sequence of -581 to -557.

Base Sequence↗
PubMed1999

An isoform of Nurr1 functions as a negative inhibitor of the NGFI-B family signaling.

NGFI-B, Nurr1 and NOR-1 constitute a distinct subfamily within the nuclear receptor superfamily. To clarify the transcriptional regulation by the NGFI-B family, we searched for other components that can bind to the NBRE response element, a known target sequence for these transcription factors. By low stringency hybridization using the DNA binding domain of NOR-1 as a probe, a C-terminal truncated Nurr1 isoform, named Nurr2, was isolated from a mouse MC3T3-E1 cell cDNA library. Nurr2 had a novel cryptic exon located upstream in the Nurr1 promoter region, and was generated by alternative splicing at exons 1, 2 and 6. The C-terminal region was encoded by frame-shifted exon 6, and so Nurr2 lacked the C-terminal sequences corresponding to the putative ligand binding domain or dimerization domain. Quantitative reverse transcriptase-PCR experiments confirmed the presence of the Nurr2 isoform in mouse, rat and human. It was, like Nurr1, highly expressed in the pituitary and the cerebral cortex. Nurr2 and Nurr1 were also concomitantly induced by forskolin in NIH3T3 cells. Functional analysis using a reporter gene, containing NBRE response elements, indicated that while the isoform was inactive by itself, it could inhibit transactivation by the members of the NGFI-B family. These results indicate that the C-terminal truncated isoform, Nurr2, may act as a negative regulator of the NGFI-B family signaling.

3T3 Cells↗
PubMed1999

Interleukin-1 beta upregulates cardiac expression of vascular endothelial growth factor and its receptor KDR/flk-1 via activation of protein tyrosine kinases.

Vascular endothelial growth factor (VEGF) is not only an endothelial cell-specific angiogenic factor but also a potent mediator of vascular permeability. Interleukin-1 beta (IL-1 beta) is a pro-inflammatory cytokine that has numerous effects on the pathogenesis of the tissue injury. To explore the possible regulation of the VEGF system by IL-1 beta in the heart, we examined the regulation of expression of VEGF and KDR/flk-1 (one of the VEGF receptors) by IL-1 beta using cardiac myocytes and cardiac microvascular endothelial cells (CMEC). Both cardiac myocytes and CMEC substantially expressed VEGF mRNA and its expression was increased 3.6- and 2.4-fold by IL-1 beta, respectively. IL-1 beta-induced accumulations of VEGF mRNA in cardiac myocytes were abolished by the tyrosine kinase inhibitor genistein, whereas inhibition of protein kinase C (PKC) by staurosporin, calphostin C and phorbol ester-induced PKC depletion, and intracellular Ca2+ chelators did not affect the induction of VEGF mRNA by IL-1 beta. Relatively smaller amounts of KDR/flk-1 mRNA were detected in CMEC, but not in cardiac myocytes, and the analysis using quantitative reverse transcription-polymerase chain reaction revealed that IL-1 beta significantly stimulated the accumulation of KDR/flk-1 mRNA 3.0-fold. VEGF protein (23 kDa) levels in Western blot analysis were increased 4.2- and 3.4-fold by IL-1 beta in cardiac myocytes and CMEC, respectively. KDR/flk-1 protein (230 kDa) levels in CMEC were also increased 3.2-fold by IL-1 beta. In addition, pre-treatment of CMEC by IL-1 beta markedly enhanced VEGF-induced tyrosine phosphorylation of focal adhesion kinase compared with that in the unstimulated cells. These findings indicate that cardiac VEGF-KDR/flk-1 system is upregulated by IL-1 beta via activation of tyrosine kinases, suggesting that the IL-1 beta-modulated autocrine and/or paracrine system of VEGF has an important role in the process of angiogenesis in ischemic hearts.

Animals↗
PubMed1999

Postoperative lung volume calculated by chest computed tomography in patients with esophageal cancer.

It has been reported that, due to the severe surgical stress of thoracotomy, respiratory function after esophagectomy under thoracotomy worsened as late as a month after surgery. To investigate the mechanism of the reduction of the respiratory function, we utilized chest CT to analyze separately the changes in the lung volume of the thoracotomized side and the other side. Here, we reported the results of our comparative study of lung volume and respiratory function, which was performed by spirogram before esophagectomy and 6 months afterwards. We selected twenty-three patients who had undergone esophagectomy under right thoracotomy. Fourteen of the selectees received standard thoracotomy, while the other nine had the anterior serratus muscle and the latissimus dorsi muscle preserved. Total lung volume was found to have decreased from a preoperative value of 4077 +/- 674 ml (mean +/- SD) to a postoperative value of 3964 +/- 774 ml, and right-lung volume significantly decreased from 2229 +/- 397 to 2023 +/- 397 ml, while left-lung volume tended to increase. While right-lung volume in standard thoracotomy displayed a significant decrease from 2264 +/- 334 to 1949 +/- 424 ml, that in muscle-preserving thoracotomy showed almost no change. Spirogram revealed that vital capacity had decreased from 3574 +/- 601 to 2666 +/- 576 ml, and forced expiratory volume in the first second showed a significant decrease from 2680 +/- 500 to 2249 +/- 485 ml. Comparing the decreasing rate, the correlation coefficients between right-lung volume and %VC was 0.58. These results suggested that a change of lung volume in the thoracotomized side could play a role in the post-operative decrease of vital capacity and that muscle-preserving thoracotomy might induce less surgical stress than standard thoracotomy.

Adult↗
PubMed1999

Intestinal blood-flow velocity in uncomplicated preterm infants during the early neonatal period.

BACKGROUND: Intestinal blood-flow changes after birth. Objective. To elucidate the factors influencing intestinal blood-flow velocity in preterm infants during the early neonatal period. MATERIALS AND METHODS: We measured blood-flow velocity in the superior mesenteric artery by pulsed Doppler US in 44 uncomplicated infants with a gestational age of less than 34 weeks and from 1 to 6 days of age. RESULTS: Time-averaged mean blood-flow velocity significantly increased with age from 1 to 6 days old. There was a significant correlation of time-averaged mean blood-flow velocity with birth weight at 1, 2, 4, 5 and 6 days of age and with the amount of enteral feeding from 4 to 6 days of age. Multivariate analysis showed that partial correlation of time-averaged mean blood-flow velocity with birth weight at 2 days of age and that with the amount of enteral feeding at 5 days of age were significant. End-diastolic blood-flow velocity was significantly lower at 1 day of age in infants with patent ductus arteriosus than those without it. CONCLUSIONS: Age, birth weight, the amount of enteral feeding and patent ductus arteriosus are included in the determinants of intestinal blood-flow velocity in preterm infants.

Aging↗