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W Ju

Publications and source records attributed to W Ju.

At least 37 records · Page 2Linked to original sources
PubMed1999

Late infantile neuronal ceroid lipofuscinosis is due to splicing mutations in the CLN2 gene.

Late infantile neuronal ceroid lipofuscinosis, LINCL, is one of the most common pediatric neurodegenerative disorders. It is caused by mutations in the CLN2 gene, which encodes a lysosomal pepstatin-insensitive peptidase (LPIP). We have identified a novel mutation, T523-1G --> A, by molecular analyses of three unrelated LINCL cases. The mutation was found to affect a 3' intronic splicing acceptor site, resulting in an aberrant mRNA with an insertion of 146 bp of intronic sequence. This causes a frame shift, produces a nonfunctional truncated protein, and results in LINCL.

Adenine↗
PubMed1999

5-HTTLPR variants not associated with autistic spectrum disorders.

To determine whether there is an association of polymorphic variants of the serotonin transporter (5-HTT) gene-linked polymorphic region (5-HTTLPR) and autistic spectrum disorders, we analyzed the 5-HTTLPR genotypes of 72 autistic subjects, 11 fragile X syndrome patients with autistic behavior, 43 normal subjects, and 49 fragile X syndrome non-autistic subjects. The distribution frequency of 5-HTTLPR long allele (L) and the short allele (S) variants showed no differences between subjects. Our findings do not support the hypothesis that polymorphic 5-HTTLPR variants are a susceptibility factor for autistic disorders.

Alleles↗
PubMed1998

Molecular screening of Batten disease: identification of a missense mutation (E295K) in the CLN3 gene.

Batten disease, the juvenile form of neuronal ceroid lipofuscinosis, is a prevalent neuron degenerative disorder of childhood. A 1.02-kb genomic deletion in the Batten disease gene CLN3 has been determined to be a common mutation. We developed a PCR method to screen for this deletion and tested 43 Batten disease probands. We found 36% (31/86) of Batten disease chromosomes did not carry the 1.02-kb deletion. Of the three heterozygotes for the 1.02-kb deletion, a novel G-to-A missense mutation at nucleotide 1020 of the CLN3 cDNA sequence was found on two of the non-1.02-kb deletion chromosomes. The missense mutation resulted in a substitution of glutamic acid (E) by lysine (K) at position 295 (E295 K). The E295 K mutation causes a change in predicted local protein conformation. This glutamic acid is a highly conserved acidic amino acid, being present in human, mouse, dog and yeast, which suggests it may play an important role in the function of the Batten disease protein.

Alternative Splicing↗
PubMed1998

Two common mutations in the CLN2 gene underlie late infantile neuronal ceroid lipofuscinosis.

Late infantile neuronal ceroid lipofuscinosis (LINCL) is one of the most common pediatric neuronal degenerative disorders. A candidate gene underlying this disease, designated CLN2, was recently cloned and the gene product was characterized as a lysosomal pepstatin-insensitive carboxypeptidase (LPIC). Four mutations were identified in CLN2 from three unrelated LINCL individuals. To investigate further the mutation frequency in LINCL, we screened 16 LINCL probands for these four mutations. The previously reported intronic mutation, T523-1 G-->C. was found in 56% (9/16) of the cases, of which two were homozygous and accounted for 34% (11/32) of LINCL chromosomes. The previously reported nonsense mutation, 636 C-->T leading to R208stop, was found in 31% (5/16) of the cases, including one homozygote and accounted for 19% (6/32) of LINCL chromosomes. Two previously described missense mutations, 1107 T-->C and 1108 G-->A, were not detected in any of these 16 probands. In total, the two observed mutations, T523-1 G-->C and 636 C-->T, accounted for 53% (17/32) of LINCL alleles. Thus, one or both mutations were seen in 11 (69%) cases and no mutation has yet been identified in five. Our finding that these two mutations are common in LINCL cases adds further evidence in support of the idea that dysfunction of LPIC underlies LINCL. Positive molecular testing can now complement clinical diagnosis of LPIC and will allow for pre-natal diagnosis for subsequent pregnancies.

Aminopeptidases↗
PubMed1998

A phase I/II study of the protease inhibitor indinavir in children with HIV infection.

BACKGROUND: Indinavir, an inhibitor of the human immunodeficiency virus type 1 (HIV-1) protease, is approved for the treatment of HIV infection in adults when antiretroviral therapy is indicated. We evaluated the safety and pharmacokinetic profile of the indinavir free-base liquid suspension and the sulfate salt dry-filled capsules in HIV-infected children, and studied its preliminary antiviral and clinical activity in this patient population. In addition, we evaluated the pharmacokinetic profile of a jet-milled suspension after a single dose. METHODS: Previously untreated children or patients with progressive HIV disease despite antiretroviral therapy or with treatment-associated toxicity were eligible for this phase I/II study. Three dose levels (250 mg/m2, 350 mg/m2, and 500 mg/m2 per dose given orally every 8 h) were evaluated in 2 age groups (<12 years and >/=12 years). Indinavir was initially administered as monotherapy and then in combination with zidovudine and lamivudine after 16 weeks. RESULTS: Fifty-four HIV-infected children (ages 3.1 to 18.9 years) were enrolled. The indinavir free-base suspension was less bioavailable than the dry-filled capsule formulation, and therapy was changed to capsules in all children. Hematuria was the most common side effect, occurring in 7 (13%) children, and associated with nephrolithiasis in 1 patient. The combination of indinavir, lamivudine, and zidovudine was well tolerated. The median CD4 cell count increased after 2 weeks of indinavir monotherapy by 64 cells/mm3, and this was sustained at all dose levels. Plasma ribonucleic acid levels decreased rapidly in a dose-dependent way, but increased toward baseline after a few weeks of indinavir monotherapy. CONCLUSIONS: Indinavir dry-filled capsules are relatively well tolerated by children with HIV infection, although hematuria occurs at higher doses. Future studies need to evaluate the efficacy of indinavir when combined de novo with zidovudine and lamivudine.

Adolescent↗
PubMed1997

Effects of cadmium, copper, and zinc and beta APP processing and turnover in COS-7 and PC12 cells. Relationship to Alzheimer disease pathology.

The effects of cadmium, copper, and zinc on beta APP metabolism were investigated in COS-7 and PC12 cells. Cadmium chloride (CdCl2) increased beta APP steady-state protein levels and decreased beta APP posttranslational processing. These changes were not accompanied by alterations in beta APP mRNA levels or splicing. In addition, cytosolic alpha-actin and G3PDH levels were not affected. Further, neither zinc (ZnCl2) nor copper (CuSO4) altered beta APP levels or affected its normal processing. Pulse-chase studies revealed that the rate of beta APP maturation decreased twofold in the presence of 25 microM CdCl2 compared to untreated controls. beta APP secretion from the cell also dramatically slowed. These two factors result in the accumulation of partially processed beta APP inside cells. The presence of CdCl2 also decreased the amount of an 8-kDa beta APP C-terminal fragment, indicating that the cellular compartment in which beta APP accumulates is not accessible to alpha-secretase. Studies using Brefeldin A suggest that this compartment may be the cis or medial Golgi. However, A beta production was proportionately increased. These data show that CdCl2 can modulate the beta APP cleavage to favor A beta. Finally, beta APP mis- metabolism was shown to be unrelated to the hsp70 induction elicited by CdCl2; both heat shock and CuSO4 induced hsp70 but had no effect on steady-state levels of beta APP, although heat shock did slow beta APP maturation. These data indicate that hsp70 alone cannot chaperone beta APP through an alternate processing pathway leading to A beta production.

Amyloid Precursor Protein Secretases↗
PubMed1996

Fragile X "gray zone" alleles: AGG patterns, expansion risks, and associated haplotypes.

The risk for fragile X "gray-zone" alleles to expand appears to depend on the absence of stabilizing AGGs, which interrupt the CGG repeat region. To characterize such alleles better, we analyzed a series of 101 chromosomes with triplet repeat lengths ranging from 35 to 59 for variations in their AGG interspersion patterns. Among these, 11.9% had 3 AGGs, 59.3% had 2, 24.8% had 1, and 4.0% had 0. An inverse relationship between FMR1 repeat length and the number of interrupting AGGs was observed. Within the range of 35-44 repeats, 98.7% of alleles were found to have a pure CGG repeat length (PCGG) of less than 33. However, among alleles with 45-59 repeats, 50% were found to have 0 or 1 AGG and a PCGG of more than 33. Thus, gray-zone alleles with 45-59 repeats frequently have a long stretch of pure CGGs and thus are more likely to be unstably inherited than alleles with 35-44 repeats. We found length associations of PCGG with 2 flanking microsatellites, DXS548 and FRAXAC1: a PCGG < or = 20 was strongly associated with haplotype 20-19, whereas a PCGG > 20 was more strongly associated with the haplotype 25-21. This result could reflect a founder effect or a generalized instability of CGGs and microsatellites.

Alleles↗
PubMed1996

A survey of FRAXE allele sizes in three populations.

FRAXE is a fragile site located at Xq27-8, which contains polymorphic triplet GCC repeats associated with a CpG island. Similar to FRAXA, expansion of the GCC repeats results in an abnormal methylation of the CpG island and is associated with a mild mental retardation syndrome (FRAXE-MR). We surveyed the GCC repeat alleles of FRAXE from 3 populations. A total of 665 X chromosomes including 416 from a New York Euro-American sample (259 normal and 157 with FRAXA mutations), 157 from a Chinese sample (144 normal and 13 FRAXA), and 92 from a Finnish sample (56 normal and 36 FRAXA) were analyzed by polymerase chain reaction. Twenty-seven alleles, ranging from 4 to 39 GCC repeats, were observed. The modal repeat number was 16 in the New York and Finnish samples and accounted for 24% of all the chromosomes tested (162/665). The modal repeat number in the Chinese sample was 18. A founder effect for FRAXA was suggested among the Finnish FRAXA samples in that 75% had the FRAXE 16 repeat allele versus only 30% of controls. Sequencing of the FRAXE region showed no imperfections within the GCC repeat region, such as those commonly seen in FRAXA. The smaller size and limited range of repeats and the lack of imperfections suggests the molecular mechanisms underlying FRAXE triplet mutations may be different from those underlying FRAXA.

Alleles↗
PubMed1996

Fragile X founder effects and new mutations in Finland.

The apparent associations between fragile X mutations and nearby microsatellites may reflect both founder effects and microsatellite instability. To gain further insight into their relative contributions, we typed a sample of 56 unrelated control and 37 fragile X chromosomes from an eastern Finnish population for FMR1 CGG repeat lengths, AGG interspersion patterns, DXS548, FRAXAC1, FRAXE and a new polymorphic locus, Alu-L. In the controls, the most common FMR1 allele was 30 repeats with a range of 20 to 47 and a calculated heterozygosity of 88%. A strong founder effect was observed for locus DXS548 with 95% of fragile X chromosomes having the 21 CA repeat (196 bp) allele compared to 17% of controls, while none of the fragile X but 69% of controls had the 20 repeat allele. Although the FRAXAC1 locus is much closer than DXS548 to FMR1 (7 kb vs. 150 kb), there was no significant difference between fragile X and control FRAXAC1 allele distributions. The FRAXE repeat, located 600 kb distal to FMR1, was found to show strong linkage disequilibrium as well. A newly defined polymorphism, Alu-L, located at approximately 40 kb distal to the FMR1 repeat, showed very low polymorphism in the Finnish samples. Analysis of the combined loci DXS548-FRAXAC1-FRAXE showed three founder haplotypes. Haplotype 21-19-16 was found on 27 (75%) of fragile X chromosomes but on none of controls. Three (8.4%) fragile X chromosomes had haplotypes 21-19-15, 21-19-20, and 21-19-25 differing from the common fragile X haplotype only in FRAXE. These could have arisen by recombination or from mutations of FRAXE. A second haplotype 21-18-17 was found in four (11.1%) fragile X chromosomes but only one (1.9%) control. This may represent a more recent founder mutation. A third haplotype 25-21-15, seen in two fragile X chromosomes (5.6%) and one (1.9%) control, was even less common and thus may represent an even more recent mutation or admixture of immigrant types. Analysis of the AGG interspersions within the FMR1 CGG repeat showed that 7/8 premutation chromosomes lacked an AGG whereas all controls had at least one AGG. This supports the hypothesis that the mutation of AGG to CGG leads to repeat instability and mutational expansion.

Finland↗
PubMed1994

Ribozyme mediated degradation of beta-amyloid peptide precursor mRNA in COS-7 cells.

Two sets of eucaryotic expression vectors encoding trans-acting hammerhead ribozymes and trans-acting hairpin ribozymes were constructed. In one set of vectors ribozyme RNA transcription was placed under the control of a mouse mammary tumor virus long terminal repeat (MMTV-LTR). In the other set ribozyme expression was controlled by a metallothionein IIA (Mt-IIA) promoter. Each ribozyme was directed to the first target sequence in the Alzheimer amyloid peptide precursor mRNA (beta APP mRNA), 5' decreases GUC decreases 3'. Ribozyme RNA transcribed from these vectors, which should cleave all six alternatively spliced forms of beta APP mRNA as well as beta APP pre-mRNA, was shown to cleave a beta APP RNA substrate analog in vitro. Stably transfected COS-7 cell lines bearing both vector types were prepared. Steady-state levels of beta APP mRNA were reduced 25-30% in cells containing either active or mutant hammerhead ribozyme vectors driven by the MMTV-LTR promoter grown in the presence of glucocorticoids. In cell lines bearing Mt-IIA driven ribozymes steady-state levels of beta APP mRNA were reduced 67-80% in both hammerhead and hairpin ribozyme containing cell lines following promoter induction by glucocorticoids. These levels correlate with the appearance of low levels of induced ribozyme RNA. In contrast, steady-state alpha-actin mRNA and G3PDH mRNA levels in these cells remained constant. Western blotting of cell extracts revealed that all forms of beta APP were correspondingly reduced. Neither the RNA nor protein decreases observed in ribozyme transfected cell lines were observed in stably transfected control cells bearing the vector alone. These results suggest that ribozyme-mediated degradation of beta APP mRNA in COS-7 cells does not depend on ribozyme cleavage.

Amyloid beta-Protein Precursor↗
PubMed1994

Concentration and distribution of infectivity and PrPSc following partial denaturation of a mouse-adapted and a hamster-adapted scrapie strain.

PrPSc is a specific protein marker for slow infectious diseases known as the transmissible subacute spongiform encephalopathies. Although PrPSc is closely associated with infectivity, it is not known if it is the infectious agent itself, a component of the agent or merely adventitiously associated with infectivity. In the present study we demonstrate that the resistance of PrPSc to partial denaturation and of infectivity to inactivation differs markedly for two scrapie strains. Proteinase K treatment or electrophoretic analysis of partially denatured PrPSc preparations reveal a dissociation between infectivity and demonstrable PrPSc. Our findings support other evidence that not all PrPSc is required for infectivity. Our studies combined with previous biological analyses suggest that PrPSc cannot be the sole component associated with the infectious agent.

Animals↗
PubMed1992

Demonstration of scrapie strain diversity in infected PC12 cells.

Scrapie strain replication in the nerve growth factor-induced, differentiated PC12 cell culture system was examined. Differences in replication between mouse-derived agents were demonstrated, with the 139A scrapie strain yielding 100- to 1000-fold higher levels of infectivity than the ME7 scrapie strain. Replication was not detected in PC12 cells infected with either the hamster-derived 263K or rat-derived 139R scrapie strains. Studies on the neurotransmitters in infected PC12 cells demonstrated that the adrenergic pathway was unchanged but the cholinergic pathway was altered. Furthermore, the degree of alteration correlated with the level of scrapie strain replication. Comparison of infectivity titres and enzymatic changes in ME7-infected PC12 cells with those in Chandler agent-infected mouse neuroblastoma cells suggests that the significant changes in neurotransmitter levels in cultures exhibiting low titres of infectivity involve factors in addition to strain replication. The variation in the range of scrapie strain replication in PC12 cells is discussed in relationship to species barrier, cell targeting, genetic susceptibility and species strain specificity. These studies further emphasize the value of the PC12 cell model system in examining the scrapie strain-host cell interaction and in addition support the concept of variation among scrapie strains.

Acetylcholinesterase↗
PubMed1991

Malignant and nonmalignant T cell lines from human T cell lymphotropic virus type I-negative patients with Sézary syndrome.

The establishment of an in vitro model for cutaneous T cell lymphomas and Sézary syndrome has been difficult since T cells from individuals with these diseases do not proliferate in response to T cell mitogens. We found that conditioned media, collected from mitogen-activated PBMC from Sézary patients, contain an IL-2 receptor inducing factor. Despite their ostensible proliferative disorder, using a combination Sézary cell-conditioned media and rIL-2, we established IL-2 responsive, human T cell lymphotropic virus type I negative T cell lines from 23 patients, nine of which contain cells with the structural and/or genetic characteristics of neoplastic Sézary T cells.

Cell Division↗
PubMed1991

A clonal CD4-positive T-cell line established from the blood of a patient with Sézary syndrome.

The reported inability to establish long-term T-cell lines from the blood of cutaneous T-cell lymphoma patients with circulating neoplastic T cells has hindered the development of an in vitro system to investigate Sézary syndrome. We have established a rapidly proliferating T-cell line from the peripheral blood of a patient with Sézary syndrome, which expresses a mature helper T-cell phenotype and contains cytogenetic abnormalities and T-cell receptor gene rearrangements identical to those in the patient's blood. The method of establishment and characteristics of this line are described.

Aged↗