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Biomedical subjects

Y Furuichi

Publications and source records attributed to Y Furuichi.

At least 55 records · Page 3Linked to original sources
PubMed1999

N-glycosylation is involved in the sensitivity of Saccharomyces cerevisiae to HM-1 killer toxin secreted from Hansenula mrakii IFO 0895.

Saccharomyces cerevisiae rhk mutants were previously shown to have a phenotype that is resistant to HM-1 killer toxin secreted from Hansenula mrakii IFO 0895. The RHK1/ALG3 gene encodes a mannosyl-transferase that is involved in the synthesis of an oligosaccharide in protein N-glycosylation. Previously, this gene was cloned and shown to complement the rhk1 mutation. In this study, the RHK2 gene, which complements the rhk2 mutation, was cloned. The RHK2 gene was found to be identical to the essential gene STT3, which encodes a subunit of the oligosaccharyl-transferase complex. This complex transfers the core oligosaccharide to proteins. The rhk2 mutants showed supersensitivity to several drugs (Calcofluor White, caffeine and FK506), suggesting that these strains have cell-wall defects. Activity staining of invertase in an acrylamide gel indicated that it was underglycosylated. These results suggest that one or more mannoproteins are involved in the cytocidal process of HM-1.

Benzenesulfonates↗
PubMed1999

Immunological diagnosis of Werner syndrome by down-regulated and truncated gene products.

Although immunological methods are widely used to diagnose various infectious diseases, they have rarely been employed to detect genetic diseases. In this study, we have established an immunoblot analysis system for the diagnosis of Werner syndrome (WS), a recessive genetic disorder causing premature aging and an enhanced risk of rare cancers. The method uses an immunoblot technique with specific monoclonal antibodies to WS gene product, and B-lymphoblastoid cell lines (LCLs) transformed by Epstein-Barr virus; these cell lines express an increased level of normal WS gene product DNA helicase. The method clearly distinguishes normal from patient LCLs containing any of the mutation types found so far in Japan, primarily because of the drastically reduced levels of mutated gene products, and secondarily because of the truncated product sizes. A comparison of this immunological diagnosis with the symptom-based clinical diagnosis has narrowed down the criteria of symptoms essential for WS diagnosis. This procedure is compatible with, and has some advantage over, the genetic method, because WS patients can be diagnosed without determining the mutated gene sequences. The method exemplified in WS may also be applied to detect some other genetic diseases.

Adult↗
PubMed1999

Effects of dietary alpha- or gamma-linolenic acid on levels and fatty acid compositions of serum and hepatic lipids, and activity and mRNA abundance of 3-hydroxy-3-methylglutaryl CoA reductase in rats.

The effects of diets containing equal amounts of alpha (alpha)- or gamma (gamma)-linolenic acid on lipid metabolism were compared in rats. Four groups of male Wistar rats were given the diets containing 20% perilla/corn mixed oil or borage oil in the absence (PO- and BO-diets, respectively) or presence (CPO- and CBO-diets) of cholesterol for 20 days. The PO-diet yielded lower serum cholesterol than the BO-diet, although the difference was not observed between the CPO and CBO groups. The PO and CPO groups showed lower high-density lipoprotein cholesterol than the BO and CBO groups, respectively. A similar tendency was observed in serum phospholipids. The CPO-diet gave markedly lower hepatic triglycerides than the CBO-diet. The activity of hepatic 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase was much lower on the PO-diet than on the BO-diet. mRNA abundance of HMG-CoA reductase was lower in rats on the PO-diet than on the BO-diet, though there was no significant difference between the CPO and CBO groups. The present results indicate that alpha-linolenic acid exhibits a larger hypocholesterolemic effect than gamma-linolenic acid, and it may be displayed mainly through the repression of the activity and mRNA expression of HMG-CoA reductase.

Animals↗
PubMed1999

Retention of fluoride/triclosan in plaque following different modes of administration.

The aim of the present investigation was to compare: (i) de novo plaque formation, and (ii) fluoride and triclosan concentration in approximal plaque, when a NaF/triclosan/Gantrez-containing dentifrice slurry or a mouthrinse were administrated during a 2-week period of no mechanical plaque control. 10 subjects rinsed for 60 s, 2x daily, for a 14-day period with one of the following 3 test products: (A) a dentifrice slurry including 1 ml of a NaF/triclosan/Gantrez dentifrice mixed with 10 ml of tap water, (B) 10 ml of a NaF/triclosan/ Gantrez mouthrinse, or (C) 10 ml of a NaF mouthrinse. De novo plaque formation was assessed on days 4, 7 and 14 using the Turesky's modification of the Quigley and Hein index system. Samples of approximal plaque were obtained immediately after clinical examination on day 14. The samples were analyzed with respect to concentration of fluoride and triclosan using an ion-specific electrode and a HPLC system, respectively. The 14-day period was repeated using another test product until all 10 subjects had used all 3 test products in a randomized order. The results showed that: (i) significantly more fluoride was retained in the approximal plaque following periods A and B than period C, and (ii) less plaque was formed during period B than periods A and C.

Anti-Infective Agents, Local↗
PubMed1999

The effect of a triclosan/copolymer dentifrice on healing after non-surgical treatment of recurrent periodontitis.

The present study examined whether the daily use of a triclosan/copolymer dentifrice enhanced healing following non-surgical periodontal therapy at sites with progressive attachment loss in periodontitis-susceptible subjects: 60 subjects who had been (i) treated for advanced periodontal disease using nonsurgical means and (ii) had been enrolled, for at least 3-5 years, in a maintenance care program that called for prophylaxis once every 3 months. During the course of this maintenance period, all 60 subjects had suffered recurrent periodontitis at > or = 2 sites at several intervals. Following a baseline examination, all 60 subjects received, on an individual basis, detailed instruction in proper self-performed plaque control methods. They were stratified in 2 balanced groups (test and control groups). The members of the test group were assigned to use a triclosan/copolymer/fluoride-containing dentifrice, while the control group used a placebo dentifrice. During the following 3 years, all participants were recalled every 3 months for an evaluation of their oral hygiene standard. Re-examinations were performed after 6, 12, 24 and 36 months. In conjunction with the re-examinations, sites (loser sites) which exhibited additional probing attachment loss (> or = 2 mm) were identified. The loser sites were exposed to professional therapy. Thus, the site was anaesthetized and the surface carefully scaled and root planed (S/RP). Alterations regarding probing pocket depth (PPD), probing attachment level (PAL), and bleeding on probing (BoP) that occurred in the interval between S/RP and 36 months were analyzed. In the control group, 126 loser sites, 67 identified at the 12-month and 59 at the 24-month examinations, were subjected to S/RP. The corresponding number of loser sites in the test group was 85 (48 at 12 months and 37 at 24 months). At the time of S/RP, about 60% of the sites were BoP (+) in both groups. Following treatment, there was a reduction in the number of sites with gingivitis. While the reduction in the control group was modest (6.8%), in the test group, the improvement was more marked (27.5%). Following S/RP, there was also a reduction of the mean PPD in both groups. This decrease amounted to 1.7 mm in the test group and was significantly (p<0.05) smaller (0.6 mm) in the control. Finally in the interval between S/RP and 36 months, there was an improvement of the probing attachment level in both groups. The mean PAL gain was, however, significantly higher in the test than in the control group (1.8 mm versus 0.7 mm; p<0.01).

Anti-Infective Agents, Local↗
PubMed1999

Influence of different curette insertion depths on the outcome of non-surgical periodontal treatment.

This study was undertaken to compare the effects of scaling and root planing (Sc/RP) performed from approximately 1 mm coronal to (test Sc/RP) or at the bottom of (control Sc/RP) the probeable pocket to the gingival margin. 2 male and 5 female patients with moderate to severe periodontitis participated in the study. Initial examination was performed with respect to probing pocket depth (PPD) and probing attachment level (PAL) using a pressure-controlled periodontal probe and stents. The patients received repeated instruction in oral hygiene, and their plaque control reached an excellent level. Baseline examination including PPD and PAL measurements was then performed. Following the baseline examination, single-rooted teeth in 1 quadrant of each dentition were randomly selected and subjected to the test Sc/RP (test teeth) or control Sc/RP (control teeth). The PPD and PAL were measured 1 and 3 months following Sc/RP. It was demonstrated that: (i) the PPD reduction following Sc/RP was larger at the sites with initially deep pockets than at the sites with shallow pockets; (ii) the mean PPD reduction at the sites with an initial PPD > or =3.5 mm was significantly larger in the control teeth than in the test teeth; (iii) there was a significant PAL gain in the initially deep pockets but not in the initially shallow pockets; (iv) the PAL gain in the initially shallow pockets was significantly larger in the control teeth than in the test teeth. In the treatment of periodontitis, trauma caused by Sc/RP to the most coronal part of the connective tissue attachment seems to be of minor importance compared to the effective removal of subgingival deposits.

Adult↗
PubMed1999

Mutations in RECQL4 cause a subset of cases of Rothmund-Thomson syndrome.

Rothmund-Thomson syndrome (RTS; also known as poikiloderma congenitale) is a rare, autosomal recessive genetic disorder characterized by abnormalities in skin and skeleton, juvenile cataracts, premature ageing and a predisposition to neoplasia. Cytogenetic studies indicate that cells from affected patients show genomic instability often associated with chromosomal rearrangements causing an acquired somatic mosaicism. The gene(s) responsible for RTS remains unknown. The genes responsible for Werner and Bloom syndromes (WRN and BLM, respectively) have been identified as homologues of Escherichia coli RecQ, which encodes a DNA helicase that unwinds double-stranded DNA into single-stranded DNAs. Other eukaryotic homologues thus far identified are human RECQL, Saccharomyces cerevisiae SGS1 and Schizosaccharomyces pombe rqh1. We recently cloned two new human helicase genes, RECQL4 at 8q24.3 and RECQL5 at 17q25, which encode members of the RecQ helicase family. Here, we report that three RTS patients carried two types of compound heterozygous mutations in RECQL4. The fact that the mutated alleles were inherited from the parents in one affected family and were not found in ethnically matched controls suggests that mutation of RECQL4 at human chromosome 8q24.3 is responsible for at least some cases of RTS.

Adenosine Triphosphatases↗
PubMed1999

Bloom's syndrome gene suppresses premature ageing caused by Sgs1 deficiency in yeast.

BACKGROUND: Bloom's syndrome (BS) is an autosomal recessive disorder causing short stature, immunodeficiency, and an increased risk of cancer. Increased rates of sister chromatid exchange and chromosomal aberration have been observed in cells having defects in the BLM gene. Among five kinds of human RecQ helicases cloned, the mutations in WRN and RecQL4 have been known as the causes of premature ageing. Little is, however, known about the function of BLM helicase in ageing. RESULTS: We show that human BLM, but not WRN can prevent the premature ageing and the increased homologous recombination at the rDNA loci caused by sgs1 mutation. Unexpectedly, the levels of ERCs (extrachromosomal rDNA circles), the products of homologous recombination, formed in 7-generation cells of the wild-type or the sgs1:BLM strain were comparable with those of the sgs1 or the sgs1:WRN age-matched-old cells. CONCLUSION: These results imply that BLM helicase may have an important role in human ageing. In addition, these data suggest that the accumulated ERCs per se may be not the cause of premature ageing in yeast, inconsistent with the model proposed by Sinclair & Guarente. We discuss a new model, which explains how Sgs1 or BLM helicase suppresses premature ageing in yeast.

Aging, Premature↗
PubMed1999

Inhibition of eukaryotic dna polymerase alpha by persimmon (Diospyros kaki) extract and related polyphenols.

The effects of persimmon extract (Diospyros kaki) and related polyphenols on eukaryotic DNA polymerase alpha were examined. It was found that persimmon extract, epigallocatechin gallate, and epicatechin gallate strongly inhibited the activity of DNA polymerase alpha purified from calf thymus. Among these polyphenols, persimmon extract had the most potent effect on DNA polymerase alpha activity and the concentration of persimmon extract producing 50% inhibition of the activity was 0.191 microM. Persimmon extract showed a weaker effect on DNA polymerase beta and slightly inhibited primase and DNA polymerase I. The inhibition of DNA polymerase alpha by persimmon extract was competitive with the template-primer and noncompetitive with dTTP substrate. The Ki value of DNA polymerase alpha for persimmon extract was estimated to be 70 nM. Moreover, persimmon extract inhibited [3H]thymidine incorporation of human peripheral lymphocyte cells stimulated by PHA.

DNA Polymerase I↗
PubMed1999

Effects of castor oil on lipid metabolism in rats.

Weanling rats were given diets contained castor oil (CAO-diet), coconut oil (CO-diet), or high-oleic safflower oil (HO-diet) each 10% (wt). No growth retardations were observed on the CAO-diets. The CAO-diet group showed significantly lower serum cholesterol and hepatic triacylglycerols than the HO-diet group. Ricinoleic acid was found at an extremely low level in perirenal adipose tissue.

Adipose Tissue↗
PubMed1999

Multiple extra-bone accumulations of technetium-99m-HMDP.

Bone scintigraphy was performed on a woman 2 y and 10 mo after surgery for rectal cancer. Intense extra-bone accumulations of 99mTc-HMDP were visible in an aortic atherosclerosis lesion and in a metastatic liver tumor. Uptake in the metastatic lesion was confirmed by x-ray CT. Uptake in the aortic lesion was shown as typical calcification by x-ray CT.

Aged↗
PubMed1999

Hot spots observed on pulmonary perfusion imaging: a case report.

A case of hot spots observed on perfusion lung images is presented. This artifact is well known, however, it is rarely seen in our experience. Although this artifact can occur if a faulty injection technique is used, the artifact also may be caused by embolization of the MAA in the upper extremity venous blood after injection. This cause of the artifact is beyond the control of the nuclear medicine professional.

Artifacts↗
PubMed1998

Cloning of two new human helicase genes of the RecQ family: biological significance of multiple species in higher eukaryotes.

Two new human DNA helicase genes, RecQ4 and RecQ5, that belong to the RecQ helicase family were cloned and characterized. The addition of these genes increases the total to five helicase genes in the human RecQ family, which includes helicases involved in Bloom and Werner syndromes, the genetic diseases manifesting the distinctive but overlapping clinical phenotypes of immunodeficiency, premature aging, and an enhanced risk of cancer. The RecQ4 helicase is as large as the Bloom (BLM) and Werner (WRN) helicases, and its gene expression profile is organ-specific, resembling that of BLM helicase. In contrast, the RecQ5 helicase has a low molecular weight, similar to the human progenitor RecQ1 helicase, and is expressed in all the organs examined. All five human helicase genes are expressed in cultured K562 leukemia and fibroblast cells. Synchronized K562 cell cultures showed that the genes RecQ4 and BLM, and RecQ1 and WRN, seem to be upregulated at the G1/S and G2/M phases, respectively, of the cell cycle. The biological significance of multiple species of human RecQ helicases, which are apparently nonessential for life but may be related to distinct diseases, is discussed in light of the fact that unicellular organisms, like Escherichia coli and yeast, contain only one species of helicase of this particular family.

Adenosine Triphosphatases↗
PubMed1998

Homology modeling of an RNP domain from a human RNA-binding protein: Homology-constrained energy optimization provides a criterion for distinguishing potential sequence alignments.

We have recently described an automated approach for homology modeling using restrained molecular dynamics and simulated annealing procedures (Li et al, Protein Sci., 6:956-970,1997). We have employed this approach for constructing a homology model of the putative RNA-binding domain of the human RNA-binding protein with multiple splice sites (RBP-MS). The regions of RBP-MS which are homologous to the template protein snRNP U1A were constrained by "homology distance constraints," while the conformation of the non-homologous regions were defined only by a potential energy function. A full energy function without explicit solvent was employed to ensure that the calculated structures have good conformational energies and are physically reasonable. The effects of mis-alignment of the unknown and the template sequences were also explored in order to determine the feasibility of this homology modeling method for distinguishing possible sequence alignments based on considerations of the resulting conformational energies of modeled structures. Differences in the alignments of the unknown and the template sequences result in significant differences in the conformational energies of the calculated homology models. These results suggest that conformational energies and residual constraint violations in these homology-constrained simulated annealing calculations can be used as criteria to distinguish between correct and incorrect sequence alignments and chain folds.

Algorithms↗
PubMed1998

Cloning and characterization of human Sep1 (hSEP1) gene and cytoplasmic localization of its product.

We isolated and sequenced a human cDNA (designated as hSEP1) encoding both a homologue of mouse Dhm2 and budding yeast SEP1. The gene was shown to be located on the long arm of chromosome 3 (3q25-26.1). The putative hSEP1 product (hSEP1p) consisted of 1694 amino acid residues with a molecular mass of about 190 kDa. Northern blot analysis showed a major 10-kb mRNA expressed ubiquitously in various organs as well as a minor 5.5-kb mRNA expressed relatively highly in the testis and placenta. hSEP1p is localized in the cytoplasm as examined by cytochemical and Western blot analyses of fractionated cellular extracts. The biological function of hSEP1p was discussed in correlation with its cytoplasmic localization.

Amino Acid Sequence↗
PubMed1998

The delta isoform of protein phosphatase type 1 is localized in nucleolus and dephosphorylates nucleolar phosphoproteins.

The immunolocalization and substrates of protein phosphatases present in nucleolus were investigated using Swiss 3T3 cells and Novikoff hepatoma ascites cells. The protein phosphatase activity was detected in the extract of the isolated nucleoli and its activity was inhibited by okadaic acid with IC50 value of 160 nM. Immunoblotting assay indicated that PP1c delta but not PP1c alpha, PP1c gamma 1, and PP2Ac was localized in the isolated nucleoli. Confocal microscopy showed that PP1c delta was localized in nucleoli, nuclei, and cytosol, though the intensity of fluorescence at the nucleoli was stronger than that of the cytosol or nuclei. PP1c delta was co-localized with the major nucleolar phosphoprotein B23 at nucleoli. The phosphatase was capable of dephosphorylating several proteins in the nucleolus, including B23. The Km of PP1 for the recombinant B23.1, phosphorylated by endogenous kinase(s), was 3.5 microM. These results indicate that PP1c delta is the major serine/threonine phosphatase present in nucleolus and it dephosphorylates nucleolar phosphoproteins, including B23.

3T3 Cells↗