Biomedical subjects

H Tonoki

Publications and source records attributed to H Tonoki.

At least 55 records · Page 3Linked to original sources

PubMed1999

Identification of an autoimmune enteropathy-related 75-kilodalton antigen.

BACKGROUND & AIMS: We have previously reported a 75-kilodalton autoantigen specific to X-linked autoimmune enteropathy (AIE) associated with tubulonephropathy. The aim of this study was to identify the autoantigen. METHODS: Complementary DNA (cDNA) clones were isolated by immunoscreening a human duodenal cDNA-expression library with serum from a patient with AIE. RESULTS: cDNA encoding the 75-kilodalton antigen (AIE-75) was identified. The composite nucleotide sequence of the cDNA for AIE-75 was 2214 base pairs long and encoded 552 amino acids. The genomic sequence of AIE-75 was found in Sequence DataBank, which consisted of 21 exons and was located on the chromosome 11p14.3. Recombinant AIE-75 specifically reacted with sera from 3 of 4 unrelated patients with AIE but not with 58 control sera. AIE-75 was predominantly distributed in the epithelial cells of the luminal surface and the upper half of the crypts of the intestine and in the proximal renal tubulus. Similarity searches revealed that the AIE-75 cDNA sequence was an authentic form of several colon cancer-related cDNAs of unknown function. The deduced amino acid sequence contained 3 conserved PSD-95/Dlg/ZO-1 (PDZ) domains. CONCLUSIONS: AIE-75 is a PDZ domain-containing protein expressed in the differentiated epithelial cells of the intestine and kidney and may be involved in protein-protein interaction. The identification of the autoantigen may prove useful in the approach to the pathogenesis of this poorly understood disease.

Amino Acid Sequence↗

PubMed1999

Adenovirus type 5 E1A immortalizes primary rat cells expressing wild-type p53.

Adenovirus (Ad) E1A induces apoptosis in cells expressing wild-type p53, and stable transformation by Ad E1A requires the co-introduction of an anti-apoptotic gene such as Ad E1B 19K. Thus, cells immortalized by Ad E1A alone might have lost functional p53. In order to analyze the p53 in rat cells expressing Ad E1A, we established rat cell lines by transfecting primary rat embryo fibroblast (REF) and baby rat kidney (BRK) cells with cloned Ad5 E1A. By using a yeast functional assay, we analyzed p53 in six primary REF and three BRK cell lines immortalized by Ad5 E1A as well as five spontaneously immortalized rat cell lines (REF52, NRK, WFB, Rat-1 and 3Y1). The yeast functional assay revealed that all of the spontaneously and Ad5 ElA-immortalized rat cell lines except for 3Y1 expressed wild-type p53. All of the Ad5 E1A-immortalized rat cell lines contained p53 detectable by immunoprecipitation. Recombinant adenovirus expressing rat p53 cloned from a REF cell line immortalized by Ad5 E1A, as well as that expressing murine wild-type p53, induced apoptosis in p53-null cells in collaboration with E1A. Thus, it is suggested that the mutation of p53 appears to be not frequent in the spontaneous immortalization of primary rat cells, and that the functional loss of wild-type p53 is not a prerequisite of E1A-mediated immortalization.

Adenoviridae↗

PubMed1999

A novel A-kinase anchoring protein in the heart interacts with G alpha 13.

A cDNA of a tentative A-kinase anchoring protein, presumably coupled with heterotrimeric GTP binding protein alpha 13 subunit (G alpha 13), was cloned from a human heart cDNA library. It was approximately 650 bases and its mRNA was expressed in the heart. Homology search of DNA sequences revealed that it was a novel cDNA with 84% homology with the partial sequence of rabbit cDNA of AKAP 120 without a stop codon. 3'-Rapid Amplification of cDNA Ends (3'-RACE) and yeast functional assay were performed to determine the 3'-end of the cDNA and ribosomal frameshifting was suggested as a translational mechanism. Here we report that a protein encoded by the cDNA may be involved in intracellular signal transduction via the G alpha 13 and PKA in hearts.

A Kinase Anchor Proteins↗

PubMed1998

4q33-qter deletion and absorptive hypercalciuria: report of two unrelated girls.

We report on two unrelated girls with multiple malformations, each of whom had a der(4)t(4;?)(q33;?) chromosome--an unbalanced translocation chromosome with deletion of the 4q33-qter segment and addition of a segment of an unknown chromosome. One of the two girls had asymptomatic kidney stones. Both had excess urinary calcium excretion (0.53 and 0.84 mg/mg creatinine, respectively), exaggerated excretion on oral calcium load, and reduced but excessive excretion on restricted calcium intake. The urinary calcium excretion of their parents was normal. Both girls were thus diagnosed to have sporadic absorptive hypercalciuria. It was deduced that the 4q33-qter segment contains the putative gene for absorptive hypercalciuria.

Abnormalities, Multiple↗

PubMed1998

Patient with del(12)(q12q13.12) manifesting abnormalities compatible with Noonan syndrome.

We report on a Japanese boy with interstitial deletion of chromosome 12q12-q13.12, who had multiple congenital anomalies with severe psychomotor retardation. Most of the clinical manifestations were compatible with Noonan syndrome phenotype except for the absence of cardiac defects. Severe mental retardation and intrauterine onset of growth retardation may have been due to the chromosomal deletion. The interstitial deletion does not overlap a putative Noonan syndrome locus, which was recently assigned to 12q22-qter by linkage analysis. Although correlation between the phenotype and del(12)(q12q13.12) was not confirmed, because this is the first report of deletion of proximal 12q, the deleted segment may contain another Noonan syndrome locus.

Child, Preschool↗

PubMed1998

Prenatal identification of mos 45,X/46,X,+mar in a normal male baby by cytogenetic and molecular analysis.

We report a case of mos 45,X/46,X,+mar, diagnosed prenatally by amniocentesis, whose physical examination, including external and internal organs, along with serum testosterone values were normal five years after delivery. The mosaic karyotype was seen in 146 of 240 cells examined (amniotic fluid cells, 110/65; placental chorionic villi: 5/4; cord blood, 21/81; cultured skin fibroblasts, 10/90) from 386 metaphases, and the marker chromosome appeared as a small non-fluorescent acrocentric chromosome. All autosomes appeared normal, and no normal Y chromosome could be demonstrated. Analysis of 26 Y-chromosome loci by molecular techniques such as PCR, Southern analysis using multiple Y-specific DNA probes, and Hae III restriction endonuclease assessment of male-specific repeated DNA in the heterochromatic region of the Y chromosome, and fluorescence in situ hybridization (FISH), revealed the marker was derived from a Y chromosome including p terminal to q11.23, and paracentric inversion in the remaining Y long arm. The formation of testes can be considered as existence of SRY (sex-determining region of Y) as a testis-determining factor. The present report illustrates the importance of FISH and molecular techniques as a complement to cytogenetic methods for accurate identification and characterization of chromosome rearrangements in prenatal diagnosis.

Adult↗

PubMed1997

High frequency of p53 mutations in human oral epithelial dysplasia and primary squamous cell carcinoma detected by yeast functional assay.

To determine the timing and actual incidence of p53 mutations in oral epithelial lesions, we examined 33 primary squamous cell carcinomas (SCCs), 14 dysplasias and six hyperplasias from Japanese patients by a combination of yeast functional assay and DNA sequencing. The assay detects mutations of p53 mRNA between codons 67 and 347 on the basis of the DNA-binding activity of the protein. Twenty-six SCCs (79%) and five dysplasias (36%) were positive for p53 mutation, while all six hyperplasias were negative for the mutation. Human papillomavirus type 16 E6 mRNA was detected in one of seven p53 mutation-negative SCCs by reverse transcription polymerase chain reaction (RT-PCR). We further examined p53 mutations in 17 Sri Lankan oral SCCs using the yeast functional assay and the single-strand conformation polymorphism analysis of PCR-amplified DNA fragments (PCR-SSCP) of exon 5-8. The mutations were confirmed by DNA sequencing and the detection sensitivity was compared between the two methods. Six samples (35%) were positive for p53 mutation in PCR-SSCP analysis, while nine samples (53%) were positive in yeast functional assay. This suggests that the incidence of p53 mutations has been considerably underestimated in the conventional SSCP analysis. The present data indicate that p53 mutations are extremely frequent in oral cancers in the Japanese, and suggest that the timing and significance of p53 mutation in oral tumor progression vary in different ethnic populations and areas.

Adult↗

PubMed1997

New p57KIP2 mutations in Beckwith-Wiedemann syndrome.

Beckwith-Wiedemann syndrome (BWS) is characterized by numerous growth abnormalities and an increased risk of childhood tumors. The gene for BWS is localized in the 11p15.5 region, as determined by linkage analysis of autosomal dominant pedigrees. The increased maternal transmission pattern seen in the autosomal dominant-type pedigrees and the findings of paternal uniparental disomy reported for a subgroup of patients indicate that the gene for BWS is imprinted. Previously, we found p57KIP2, which is a Cdk-kinase inhibitor located at 11p15, is mutated in two BWS patients. Here, we screened for the mutation of the gene in 15 BWS patients.

Austria↗

PubMed1997

A 4 Mb cryptic deletion associated with inv(8)(q13.1q24.11) in a patient with trichorhinophalangeal syndrome type I.

We report on an 11 year old girl with trichorhinophalangeal syndrome type I (TRPS1), postaxial polydactyly of the fingers, and a de novo paracentric inversion on the long arm of chromosome 8 involving bands q13.1 and q24.11. Molecular analysis using FISH and polymorphic DNA markers detected an approximately 4 Mb, cytogenetically unidentified deletion occurring between two STSs markers, AFMB331YA9 and D8S1200, around the region of the distal inversion breakpoint. Although the deletion is large, mental retardation was not present in the patient. This is the first report of a cryptic deletion in a TRPS1 patient, both ends of which were analysed at the molecular level. The data obtained are useful for defining the location of the putative mental retardation gene(s) in TRPS1 and Langer-Giedion syndrome (TRPS2), as well as a locus for postaxial polydactyly.

Child↗

PubMed1996

Mutations in the TRKA/NGF receptor gene in patients with congenital insensitivity to pain with anhidrosis.

Congenital insensitivity to pain with anhidrosis (CIPA; MIM 256800) is an autosomal-recessive disorder characterized by recurrent episodes of unexplained fever, anhidrosis (absence of sweating) and absence of reaction to noxious stimuli, self-mutilating behaviour and mental retardation. The genetic basis for CIPA is unknown. Nerve growth factor (NGF) induces neurite outgrowth and promotes survival of embryonic sensory and sympathetic neurons. Mice lacking the gene for TrkA, a receptor tyrosine kinase for NGF, share dramatic phenotypic features of CIPA, including loss of responses to painful stimuli, although anhidrosis is not apparent in these animals. We therefore considered the human TRKA homologue as a candidate for the CIPA gene. The mRNA and genomic DNA encoding TRKA were analysed in three unrelated CIPA patients who had consanguineous parents. We detected a deletion-, splice- and missense-mutation in the tyrosine kinase domain in these three patients. Our findings strongly suggest that defects in TRKA cause CIPA and that the NGF-TRKA system has a crucial role in the development and function of the nociceptive reception as well as establishment of thermoregulation via sweating in humans. These results also implicate genes encoding other TRK and neurotrophin family members as candidates for developmental defect(s) of the nervous system.

Amino Acid Sequence↗

PubMed1995

Predominance of the mutation at 1138 of the cDNA for the fibroblast growth factor receptor 3 in Japanese patients with achondroplasia.

Fibroblast growth factor receptor 3 (FGFR3) has recently been identified as a putative gene for achondroplasia. Since a guanine to adenine mutation at 1138 of the cDNA for FGFR3 had been identified in most of the patients in Western population, we examined 13 Japanese patients to see if they also share the same mutation. Specific endonuclease digestion of the amplified coding sequence for the transmembrane domain of the FGFR3 revealed that the 12 patients have the G to A change at 1138, while the other had the G to C substitution at the same point, both of which result in G380A substitution. As far as we studied, the homogeneity of the point mutation at 1138 is also authentic to Japanese patient as well as Western patients.

Achondroplasia↗

PubMed1994

Endotoxin induces glutathione reductase activity in lungs of mice.

Glutathione reductase catalyzes the NADPH-dependent conversion of glutathione disulfide to glutathione and helps protect the lung from injury by reactive oxygen. In animals allowed to breathe nearly 100% oxygen, the activities of other antioxidants in the lung can be induced by treatment with endotoxin, and this induction is associated with increased tolerance to hyperoxia. The purpose of this study was to see whether glutathione reductase activity in the lungs of mice increased with endotoxin treatment alone. We studied 60 FVB mice (20 males and 40 females). Half received endotoxin (500 micrograms/kg) intraperitoneally at time 0 and 24 h, and the controls received an equal volume of saline. At 48 h we killed the mice and removed their lungs. Treatment of mice with endotoxin increased glutathione reductase activity in the lung 55% (0.035 +/- 0.005 to 0.054 +/- 0.010 mumol NADPH reduced/min/mg protein; mean +/- SD; endotoxin different from control, p < 0.001). The increase in activity was the same for male and female mice. We measured the specific protein for glutathione reductase by Western analysis and mRNA for glutathione reductase using a slot-blot analysis and found that both increased roughly 2-fold with endotoxin treatment. This suggests that endotoxin treatment resulted in either increased rate of transcription of glutathione reductase mRNA or increased mRNA stability. We conclude that endotoxin treatment increases glutathione reductase activity in the lung and that this increase in activity may play a role in subsequent protection from hyperoxia.

Animals↗

PubMed1994

[Establishment of Chinese hamster ovary cell lines with reduced expression of glutathione reductase after antisense-oriented gene transfection and assessment of the sensitivity to oxidant injury].

Glutathione reductase (GR) protects tissues from oxidant injury by catalysing the reduction of glutathione disulfide (GSSG) to glutathione (GSH). In order to study the effect of GR in protecting cells from oxidant injury, we generated Chinese hamster ovary (CHO) cell lines stably transformed after antisense-oriented gene transfection. The coding region of the human GR was cloned using revere transcription PCR method and selected by transient expression study in mammalian cells. A clone HGR135 showed overexpression of GR in CHO cells and was proved to have no base substitution. This clone, then, was ligated into MEP4 expression vector in an antisense orientation to the human metallothionein promoter and transfected to CHO cells with polybrene. Among 12 cell lines isolated, G17 showed to have the least GR activity (48% of the control), while another four were mildly GR deficient. Southern hybridization of genomic DNA digests and transformation experiment on E. coli revealed that the promoter-antisense coding region component was integrated. Northern hybridization detected reduced amount of GR transcript but no antisense message. Baseline cellular GSH concentrations were lower in G17 than in control (25.7 +/- 2.5 vs. 36.1 +/- 1.9 nmole/mg protein, P < 0.05), while cellular GSSG concentrations were higher (0.61 +/- 0.19 vs. 0.39 +/- 0.09 nmole/mg protein, P < 0.05). After four hours of treatment of G17 and control cells with increasing doses (1 to 10 mM) of t-butylhydroperoxide (t-BuOOH), cellular GSH concentrations in G17 decreased with an elevation of GSSG concentration at 1 mM followed by no further increase at higher t-BuOOH concentration, while GSSG concentrations increased in the control cells without reduction of GSH concentrations at 1-5 mM t-BuOOH treatment. The concentrations of GSH were lower in G17 than in controls at all doses of t-BuOOH. Four hours of exposure to 10 mM t-BuOOH resulted in greater LDH release in G17 than in control (57.3 +/- 4.7 vs. 32.1 +/- 6.5%, P < 0.05). Similarly, G17 cells released more of their LDH to the media than did CHO cells in response to exposure to 95% O2 for 72 hours (19.3 +/- 5.9 vs. 11.9 +/- 5.4%, P < 0.05). The partial GR deficiency in G17 cells impairs their ability to recycle GSSG and this deficiency offers the best explanation for the increased sensitivity of these cells to injury by t-BuOOH or hyperoxia.

Animals↗

PubMed1993

Expression of recombinant human glutathione reductase in eukaryotic cells after DNA-mediated gene transfer.

Glutathione reductase (EC 1.6.4.2) protects tissues from oxidant stress by catalyzing the NADPH-mediated reduction of glutathione disulfide to glutathione. We describe construction of a vector for DNA-mediated gene transfer and successful transient overexpression of human glutathione reductase cDNA in CHO cells. No expression was observed when the same vector was transiently transfected into NIH3T3 or LA4 cells or stably integrated in CHO cells. These results demonstrate the ability to constitute recombinant glutathione reductase expression in eukaryotic cells but suggest that this expression may be toxic.

3T3 Cells↗

PubMed1992

A symptomatic female patient with Duchenne muscular dystrophy diagnosed by dystrophin-staining: a case report.

We report a case of symptomatic carrier of Duchenne muscular dystrophy (DMD) in a 14-year-old girl with no prior family history of DMD. She presented with chest pain, enlarged calf muscles, an elevated serum creatine kinase (CK), and decreased left ventricular function. Histological examination of skeletal muscle revealed myopathic changes and immunostaining with anti-dystrophin antiserum demonstrated a mosaic pattern which are compatible with the observations in carriers of DMD. Southern blots using the dystrophin cDNA revealed no evidence of a deletion within the DMD gene in the patient or in her mother. We found this observation interesting for two reasons: 1. Cardiomyopathy is rare in female DMD patients. 2. Immunostaining of a muscle biopsy with anti-dystrophin serum proved to be valuable in the diagnosed for symptomatic carriers of the dystrophin gene mutation.

Adolescent↗

PubMed1991

Molecular study of the Prader-Willi syndrome: deletion, RFLP, and phenotype analyses of 50 patients.

Deletion and RFLP studies with 5 cloned DNA markers localized at 15q11.2 were performed in 50 patients with the Prader-Willi syndrome (PWS). A one-copy density (deletion) for at least one of 4 loci, D15S9, D15S11, D15S10, D15S12, was detected in 32 (64%) of the 50 patients; deletions of each of the 4 loci were found in 29, 30, 29, and 28 patients, respectively. Three patients showed 4 or more copy density for D15S12 locus, in addition to deletions. The remaining 18 patients showed two-copy densities for each of the 4 loci. A common site of rearrangements among our 32 patients as well as the reported patients seemed to be confined to a segment between D15S9 and D15S11, suggesting the putative PWS gene locus in this segment. Of 6 patients who have cytologic deletions but did not show any molecular deletions, 3 have normal size of hands and feet, and 4 have normally pigmented skin and hair. The normal pigmentation was also observed in 3 patients who had small molecular deletions in the examined 5-locus segment. These observations may support the conception of contiguous gene syndrome. RFLP analysis demonstrated maternal uniparental isodisomy of chromosomes 15 in both a patient with 45,t(15q;15q) and a karyotypically normal patient. Based on the results of the present study, a new model is proposed to explain the occurrence of PWS with a variety of chromosome abnormalities, including partial monosomy, disomy, trisomy, and/or tetrasomy for 15q11.2. The normal development may require an even or more "number ratio" of paternally derived allele(s) to maternally derived allele(s) of the gene(s) localized at 15q11.2, and a disturbance of the ratio would lead to the PWS phenotype.

Adolescent↗

PubMed1991

Pigmentary dysplasias in long survivors with mosaic trisomy 18: report of two cases.

We describe two patients, a 19-year-old girl and a 19-year-old boy, with mosaic trisomy 18 and pigmentary dysplasias. Both patients had profound growth and mental retardation, marked kyphoscoliosis, bushy eyebrows, bulbous nose, simple ears, and joint contractures - clinical manifestations of long survivors with mosaic or non-mosaic trisomy 18. In addition, the boy showed total asymmetry. Pigmentary dysplasias of the skin with hypopigmented whorls and streaks, initially absent or overlooked at the ages 2 and 15 years, were detected on close examination. It is advisable to check closely every long survivor with mosaic or purportedly non-mosaic trisomy 18 for pigmentary dysplasias.

Abnormalities, Multiple↗

PubMed1991

Identification of a marker chromosome as inv dup(15) by molecular analysis.

The origin of an extra marker chromosome in a patient with mental retardation and intractable epilepsy was ascertained by DNA analysis. Gene dose and restriction fragment length polymorphism (RFLP) studies of D15S9 proved that the patient was tetrasomic for the gene and that the extra chromosome was of maternal origin. On the basis of the molecular findings, further detailed GTG-banded chromosome analysis interpreted the marker chromosome as inv dup(15)(pter----q14::q14----pter). The clinical manifestations of the patient are consistent with those of the patients previously described.

Adolescent↗