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K Joh

Publications and source records attributed to K Joh.

At least 19 recordsLinked to original sources
PubMed2006

Genetic and epigenetic alterations on the short arm of chromosome 11 are involved in a majority of sporadic Wilms' tumours.

Wilms' tumour is one of the most common solid tumours of childhood. 11p13 (WT1 locus) and 11p15.5 (WT2 locus) are known to have genetic or epigenetic aberrations in these tumours. In Wilms' tumours, mutation of the Wilms tumour 1 (WT1) gene at the WT1 locus has been reported, and the WT2 locus, comprising the two independent imprinted domains IGF2/H19 and KIP2/LIT1, can undergo maternal deletion or alterations associated with imprinting. Although these alterations have been identified in many studies, it is still not clear how frequently combined genetic and epigenetic alterations of these loci are involved in Wilms' tumours or how these alterations occur. To answer both questions, we performed genetic and epigenetic analyses of these loci, together with an additional gene, CTNNB1, in 35 sporadic Wilms' tumours. Loss of heterozygosity of 11p15.5 and loss of imprinting of IGF2 were the most frequent genetic (29%) and epigenetic (40%) alterations in Wilms' tumours, respectively. In total, 83% of the tumours had at least one alteration at 11p15.5 and/or 11p13. One-third of the tumours had alterations at multiple loci. Our results suggest that chromosome 11p is not only genetically but also epigenetically critical for the majority of Wilms' tumours.

Child, Preschool↗
PubMed2006

Accelerated tubular cell senescence in SMP30 knockout mice.

An experimental model with accelerated but not drastic renal senescence seemed useful to recognize the mechanisms of how kidney function deteriorates with age. Senescence marker protein-30 (SMP30), whose expression decreased with age and was sex-independent, is mainly expressed in hepatocytes and proximal tubular cells. Therefore, we established a SMP30 deficient strain of mice with a C57BL/6 background by gene targeting to investigate whether this molecule is involved in renal tubular cell senescence. Male SMP30 knockout (SMP30Y/-) mice and male wild-type (SMPY/+) mice (n=5) aged 12 months were examined histologically. Their tubular epithelia showed the deposition of lipofuscin and the presence of senescence-associated beta-galactosidase (SA-beta-GAL). However, no tubular cells were atrophic. In electron microscopy, SMP30-KO mice showed markedly enlarged lysosomes containing an electron dense substance. These are convincing hallmarks of senescence. We recognized the early manifestation of senescence hallmarks in SMP30-KO mice at 12 months old. Thus, this model represents the first report of a mouse strain that manifests accelerated ordinal senescence in a kidney after gene manipulation.

Animals↗
PubMed2004

Gene silencing in DNA damage repair.

Silencing of DNA repair genes plays a critical role in the development of the cancer because these genes, functioning normally, would prevent the accumulation of mutations leading to carcinogenesis. Epigenetic gene silencing is an alternative mechanism to genetic gene aberration, inactivating those genes in cancer. DNA methylation and histone modification are the major factors for epigenetic regulation of gene expression. Here, we describe recent advances in understanding of epigenetic silencing of DNA repair genes and their epigenetic mechanisms involving DNA methylation and histone modification.

Animals↗
PubMed2003

Neurons but not glial cells show reciprocal imprinting of sense and antisense transcripts of Ube3a.

The human UBE3A gene shows brain-specific partial imprinting, and lack of a maternally inherited allele causes Angelman syndrome (AS), which is characterized by neurobehavioral anomalies. In several AS model mice, imprinted Ube3a expression is detected predominantly in the hippocampus, cerebellar Purkinje cells and the olfactory bulb. Therefore, imprinting of mouse Ube3a is thought to be region-specific with different levels of silencing of the paternal Ube3a allele in different brain regions. To determine cell types of imprinted Ube3a expression, we analyzed its imprinting status in embryonic brain cells by using primary cortical cell cultures. RT-PCR and immunofluorescence were performed to determine the allelic expression of the gene. The Ube3a gene encodes two RNA transcripts in the brain, sense and antisense. The sense transcript was expressed maternally in neurons but biallelically in glial cells in the embryonic brain, whereas the antisense transcript was expressed only in neurons and only from the paternal allele. Our data present evidence of brain cell type-specific imprinting, i.e. neuron-specific imprinting of Ube3a in primary brain cell cultures. Reciprocal imprinting of sense and antisense transcripts present only in neurons suggests that the neuron-specific imprinting mechanism is related to the lineage determination of neural stem cells.

Angelman Syndrome↗
PubMed2003

Inhibition of arthritis by systemic administration of endostatin in passive murine collagen induced arthritis.

OBJECTIVE: To investigate the arthritis inhibiting effect of endostatin, known to have potent antiangiogenic activity, systemically given to animal models of rheumatoid arthritis (RA). METHODS: Four kinds of monoclonal anti-type II collagen antibody followed by lipopolysaccharide (LPS) three days later were given to 6 week old, female Balb/c mice to induce arthritis. Three groups of mice received 0.2 mg/kg/day, 2 mg/kg/day, and 10 mg/kg/day of endostatin, respectively, whereas a control group received phosphate buffered saline (PBS). Endostatin or PBS was given for 13 days, starting before the development of arthritis. Arthritis was evaluated by arthritis scores and hind paw thicknesses. Mice were killed for histological examination on the 22nd day after the administration of monoclonal anti-type II collagen antibody. RESULTS: Arthritis developed within three days after LPS administration in both the control and endostatin treatment groups. No difference in the development rate of arthritis was noted between the control and endostatin treatment groups. Arthritis scores remained significantly lower in the endostatin 10 mg/kg/day group than in the control group. Hind paw thicknesses also remained significantly smaller in the endostatin 10 mg/kg/day group than in the control group. Histopathological examination showed that synovial thickening and subchondral bone erosion improved more in the endostatin treatment groups than in the control group. CONCLUSION: The systemic administration of endostatin had an arthritis inhibiting effect in RA animal models. Endostatin inhibited, in particular, pannus formation and bone destruction.

Analysis of Variance↗
PubMed2003

Renal ultrasonography is useful for evaluating diabetic renal failure.

AIM: It has been reported that the course of renal function is heterogeneous in patients with diabetic nephropathy. This study was undertaken to examine the clinical usefulness of renal ultrasonography in evaluating diabetic chronic renal failure (CRF) patients. METHODS: The renal sizes of type 2 diabetic patients with various degrees of renal injury, non-diabetic subjects without renal diseases and patients with non-diabetic CRF were measured by ultrasonography. The renal area index (RAI) was calculated from renal measurements and body surface area. The rate of renal function decline (delta l/cre) was analyzed by calculating the slope of the regression line for the reciprocal of serum creatinine concentrations over time. The correlations between delta l/cre and various clinical and laboratory parameters, including RAI, were analyzed. RESULTS: The RAI values of type 2 diabetic patients with nephropathy increased on the whole. It was also found that the RAI value of diabetic CRF patients was heterogeneous. There was a significant correlation between RAI and log delta l/cre (r = 0.492, p < 0.01). In addition to RAI, urinary protein excretion, serum albumin concentration and mean blood pressure significantly correlated with log delta l/cre. The correlation between RAI and log delta l/cre remained significant after adjustment for age, gender and serum albumin concentration. However, it was no longer significant after inclusion of mean blood pressure in the multivariate analysis. CONCLUSION: Although RAI is not a completely independent predictor of the risk of progression of diabetic renal failure, RAI could be a useful marker for the evaluation of diabetic renal failure. Renal involvement in diabetic patients is heterogeneous, and since renal ultrasonography is non-invasive and safe to perform, it is useful in evaluating diabetic CRF patients.

Analysis of Variance↗
PubMed2001

Bidirectional Glenn procedure improves the mechanical efficiency of a total cavopulmonary connection in high-risk fontan candidates.

BACKGROUND: A total cavopulmonary connection (TCPC) is a widely performed surgical procedure for Fontan candidates. High-risk candidates who have undergone the bidirectional Glenn procedure (BDG) before TCPC have shown good results. The exact mechanism of this procedure, however, is still poorly understood. We hypothesized that a volume reduction with BDG improved ventricular contractility, thereby optimizing mechanical efficiency after TCPC. METHODS AND RESULTS: We measured percent normal systemic ventricular end-diastolic volume (%N-EDV), contractility (end-systolic elastance; E(es)), afterload (effective arterial elastance; E(a)), and mechanical efficiency (ventriculoarterial coupling; E(a)/E(es)) on the basis of the cardiac catheterization data before and after TCPC. Eighteen patients who underwent staged TCPC after BDG (staged group) were compared with 29 patients who underwent primary TCPC (primary group). E(es) and E(a) were approximated as follows: E(es)=mean arterial pressure/minimal ventricular volume, and E(a)=maximal ventricular pressure/(maximal ventricular volume-minimal ventricular volume), and E(a)/E(es) was then calculated. The ventricular volume was normalized with the body surface area. A canine experimental model with conductance catheter was used to validate the accuracy of this approximation of E(es) and E(a). %N-EDV decreased after TCPC in both groups. In the staged group, a smaller ventricular volume resulted in better contractility (E(es)). Although afterload (E(a)) increased in both groups, the increment of E(a) was smaller in the staged group. These changes resulted in an improvement of E(a)/E(es) in the staged group, whereas E(a)/E(es) increased in the primary group. CONCLUSIONS: The volume reduction of BDG preceding TCPC allows for any afterload mismatch to be corrected, thereby improving ventricular energetics after TCPC.

Adolescent↗
PubMed2000

C11orf21, a novel gene within the Beckwith-Wiedemann syndrome region in human chromosome 11p15.5.

A novel gene, C11orf2, was identified by BLAST search in the human chromosome 11p15.5 region potentially responsible for Beckwith-Wiedemann Syndrome (BWS) and some cancers. Two cDNA clones with different sizes were obtained, which share a potential ORF of 399bp and are different in their 3' untranslated regions. This gene was revealed to be expressed exclusively in human heart and in almost no other tissues examined by northern blotting. Two transcripts of different sizes, 0.9 and 3.1kb, were identified in heart, consistent with the length of the two cDNA clones. The gene shows biallelic expression (non-imprinted) in fetal liver, although it is located in the imprinted domain of 11p15.5. C11orf21 codes a protein of 132 amino acids as proved by the expression of C11orf21-EGFP fusion protein in cultured cells. The EGFP-fusion protein expressed in cultured cells localized mainly in the cytoplasm.

Alleles↗
PubMed2000

Sequence-based structural features between Kvlqt1 and Tapa1 on mouse chromosome 7F4/F5 corresponding to the Beckwith-Wiedemann syndrome region on human 11p15.5: long-stretches of unusually well conserved intronic sequences of kvlqt1 between mouse and human.

Mouse chromosome 7F4/F5 is a syntenic locus of human 11p15.5 in which many imprinted genes are clustered. Transmission of aberrant human 11p15.5 or duplicated 11p causes Beckwith-Wiedemann syndrome (BWS) depending on which parent the chromosome is derived from. To analyze a syntenic mouse locus corresponding to human 11p15.5, mouse BAC contigs were constructed between Nap2 and Tapa1, in which 390 kb was sequenced between Kvlqt1 and Tapa1. An unexpected finding was that of highly conserved intronic sequences of Kvlqt1 between mouse and human, and their homologies came up to at least 160 kb because the length of this gene extended to 350 kb, suggesting the possibility of some functional constraint due to transcriptional and/or post-transcriptional regulation of this region. Many expressed sequence tags (ESTs) were mapped on this locus. Three genes, Lit1 (Kvlqt1-AS), Mtr1 and Tssc4, were identified and characterized. Lit1 is an antisense-transcript of Kvlqt1 and paternally expressed and maternally methylated throughout the developmental stage. The position where Lit1 exists corresponded to a highly conserved region between mouse and human. This transcript extends at least 60 kb from downstream to upstream of exon 10 in Kvlqt1. Tssc4 and Mtr1 carried putative open reading frames but neither was imprinted. Further characterization of this locus based on the sequence comparison between mouse and human will contribute valuable information towards resolving the mechanism of the occurrence of BWS and the associated childhood tumor.

Alleles↗
PubMed2000

Surgical management of aortopulmonary window.

OBJECTIVE: Aortopulmonary window is a rare congenital malformation involving a window-like communication between the ascending aorta and the pulmonary artery. Here, we present our experience regarding the surgical repair of an aortopulmonary window, and also assess the long-term outcome. METHODS: Thirteen children with an aortopulmonary window associated with various congenital lesions underwent a repair of the defect. The age at operation ranged from 3 days to 1 year (median age, 19 days). The patient's weight ranged from 2.1 to 7.0 kg (mean weight, 3.6 kg). The associated lesions included an interrupted aortic arch (5 patients), a ventricular septal defect (2), an atrial septal defect (1), mitral valve regurgitation (1), and tricuspid atresia [Ic] with mitral valve regurgitation (1). The aortopulmonary window was repaired with a cardiopulmonary bypass in 11 patients, and 2 patients were ligated without a cardiopulmonary bypass. RESULTS: One patient associated with tricuspid atresia died (mortality rate of 7.7%). There has been no late death during a mean follow-up of 7 years and 3 months. CONCLUSIONS: The surgical results for an aortopulmonary window are encouraging, even if such patients are associated with major cardiac anomalies and an interrupted aortic arch. Most have shown a good long-term outcome.

Aorta↗
PubMed2000

Long-term prospective study on the natural history of Wolff-Parkinson-White syndrome detected during a heart screening program at school.

UNLABELLED: In the period 1985 to 1993, a total of 802 school-aged children (284 first-graders and 518 seventh-graders) were referred to our hospital for further evaluation of electrocardiographic abnormalities. Among them, 57 (male 24 and female 33) children were confirmed as having Wolff-Parkinson-White (WPW) syndrome based on the findings of 12-lead surface electrocardiograms (ECG). According to Lindsay's criteria, the locations of the accessory pathways were as follows: Left-lateral in 10 (18%), left-posterior in 2 (4%), right-free-wall in 28 (49%), anterior-septum in 13 (23%) and posterior-septum in 3 (5%). One 12-y-old girl had multiple accessory pathways. Six patients had associated diseases: Ebstein's anomaly in 4, epilepsy in 1 and mental retardation with scoliosis in 1. Follow-up periods ranged from 2.0 to 13.0 y (mean +/- SD: 8.0 +/- 3.3 y) for 23 first-graders with WPW syndrome, and from 2.0 to 13.0y (mean +/- SD: 7.3 +/- 4.2y) for 34 seventh-graders, respectively. Initially, 5 children had at least one episode of supraventricular tachycardia (SVT) by history and 6 children developed SVT during the follow-up. One girl with multiple accessory pathways and recurrent SVT required long-term drug therapy. CONCLUSIONS: The outcome of children with WPW syndrome detected by a heart screening program at school was favorable. Our 8 y follow-up of 57 children with WPW syndrome will serve as additional information concerning the indication of radio-frequency catheter ablation therapy for WPW syndrome in children.

Adolescent↗
PubMed1999

An extremely large solitary primary paraganglioma of the lung: report of a case.

We present herein the case of a 38-year-old woman found to have an extremely large solitary primary paraganglioma of the lung. The patient presented with chest pain on exertion and a mass was discovered in the left lower lobe of the lung by chest X-rays and computed tomography (CT). As no other neoplasms were detected elsewhere, a left lower lobectomy was performed. The patient has remained well without any evidence of recurrence for 5 years since her operation. The tumor, measuring 13 x 12 x 7 cm, was composed of ovoid cells (Zellballen), which were positive for Fontana-Masson and Grimelius stains, and sustentacular cells. Immunohistochemically, the ovoid cells were positive for neuron-specific enolase, S-100, CAM5.2, Leu7, and chromogranin A, and negative for carcinoembryonic antigen and epithelial membrane antigen. The sustentacular cells were positive for S-100 protein and CAM5.2, and negative for glial fibrillary acid protein. Therefore, the tumor was diagnosed as a paraganglioma. The tumor from our patient is the largest of the 17 solitary primary pulmonary paragangliomas reported thus far in the English-language literature.

Adult↗
PubMed1999

Functional analysis of the p57KIP2 gene mutation in Beckwith-Wiedemann syndrome.

p57KIP2 is a potent tight-binding inhibitor of several G1 cyclin/cyclin-dependent kinase (Cdk) complexes, and is a negative regulator of cell proliferation. The gene encoding p57KIP2 is located at 11p15.5, a region implicated in both sporadic cancers and Beckwith-Wiedemann syndrome (BWS). Previously we demonstrated that p57KIP2 is imprinted and only the maternal allele is expressed in both mice and humans. We also showed mutations found in p57KIP2 in patients with BWS that were transmitted from the patients' carrier mothers, indicating that the expressed maternal allele was mutant and that the repressed paternal allele was normal. In the study reported here, we performed functional analysis of the two mutated p57KIP2 genes. We showed that the nonsense mutation found in the Cdk inhibitory domain in a BWS patient rendered the protein inactive with consequent complete loss of its role as a cell cycle inhibitor and of its nuclear localization. We also showed that the mutation in the QT domain, although completely retaining its cell cycle regulatory activity, lacked nuclear localization and was thus prevented from performing its role as an active cell cycle inhibitor. Consequently, no active p57KIP2 would have existed, which might have caused the disorders in BWS patients.

Animals↗
PubMed1999

Identification of epi-1 locus as a laminin alpha chain gene in the nematode Caenorhabditis elegans and characterization of epi-1 mutant alleles.

A new genetic locus, epi-1, has been identified and mapped, which affects epithelialization of various tissues in the nematode, Caenorhabditis elegans. Seven independent epi-1 mutant alleles have been obtained. These mutants have a wide spectrum of abnormalities, all seem to be caused by a primary defect of basement membrane. We have identified the epi-1 gene as a structural gene of laminin alpha chain. The sequence analyses of the gene and cDNAs revealed that the gene consists of 15 exons and encodes a protein of 3704 amino acids in an open reading frame of 11115 base pairs. The nematode alpha chain is similar to its vertebrate and fly orthologs in the domain structure. The mRNA is trans-spliced to SL1 leader RNA as many of the nematode mRNAs. Mutation sites have been identified in four alleles. Two alleles have nonsense mutations and produce truncated proteins lacking the domain necessary for the formation of a heterotrimeric laminin molecule. The other two alleles have missense mutations in domains VI and IIIb, respectively.

Alleles↗
PubMed1998

Epstein-Barr virus genome-positive tubulointerstitial nephritis associated with immune complex-mediated glomerulonephritis in chronic active EB virus infection.

Renal involvement is rare in chronic active Epstein-Barr (EB) virus infection. We report a case of a 7-year-old girl with recurrent EB virus infection. She had fever, lymphadenopathy, hepatosplenomegaly, and persistently high titres of IgG to EB virus capsid antigen (VCA) and IgG to EB early antigen with low titres of IgM to VCA. She showed mild haematuria and proteinuria, but had no symptoms of renal failure. Renal biopsy revealed immune complex-mediated glomerulonephritis, which may have been due to a persistently high titre of antibody against EB virus. In addition, a peculiar form of tubulointerstitial nephritis was found. The morphology was characterized by a papillary infolding of the tubular epithelial cell layer into the tubular lumen. The interstitium was surrounded by the infolded epithelium and contained a large number of B-cell dominant lymphocytes. EBV-encoded RNA 1 (EBER-1) gene was detected in the nuclei of some tubuloepithelial cells by in situ hybridization and may have been associated with the pathogenesis of tubulointerstitial nephritis.

Biopsy↗
PubMed1998

An evaluation of infants' growth in the Kingdom of Nepal.

BACKGROUND: The His Majesty's Government/Japan International Cooperation Agency Primary Health Care Project began in April 1993 in collaboration with the Saitama Prefectural Government, for the purpose of improving the health status of the people in model districts of the Kingdom of Nepal. Growth monitoring is one of the basic methods that defines the health and nutritional status of children. METHODS: Anthropometric indices were measured in 759 children in the Bhaktapur district. We used the World Health Organization prototype growth chart and national growth standard for Japanese children (1990) to analyze the growth data. RESULTS: We found that the average bodyweight growth curve of children up to 4 months of age followed the 50th percentile reference curve. For children of 5-12 months of age, there was a delay in bodyweight gain and the growth curve reached the 3rd percentile curve. For children more than 1 year old, the growth curve moved below the third percentile curve. Catch-up growth did not occur before the children reached 5 years of age. The main causes of catch-up growth being hampered were chronic undernutrition and inadequate nutritional balance. CONCLUSIONS: As this was the first opportunity to evaluate infant growth in this district, the first important consequence of the results was to analyze the causes of growth faltering and failure-to-thrive in Nepalese children. Even more important, was the need to give appropriate counseling on improving feeding and other health-related practices, and the most important consequence of all was to instruct Nepalese health workers that utilizing the growth charts is an integral part of health care.

Anthropometry↗