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J Ellison

Publications and source records attributed to J Ellison.

At least 55 records · Page 3Linked to original sources
PubMed1997

Murine model of Niemann-Pick C disease: mutation in a cholesterol homeostasis gene.

An integrated human-mouse positional candidate approach was used to identify the gene responsible for the phenotypes observed in a mouse model of Niemann-Pick type C (NP-C) disease. The predicted murine NPC1 protein has sequence homology to the putative transmembrane domains of the Hedgehog signaling molecule Patched, to the cholesterol-sensing regions of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase and SREBP cleavage-activating protein (SCAP), and to the NPC1 orthologs identified in human, the nematode Caenorhabditis elegans, and the yeast Saccharomyces cerevisiae. The mouse model may provide an important resource for studying the role of NPC1 in cholesterol homeostasis and neurodegeneration and for assessing the efficacy of new drugs for NP-C disease.

Amino Acid Sequence↗
PubMed1997

Accidental exposures to blood and body fluids among health care workers in dental teaching clinics: a prospective study.

The authors evaluated accidental exposures to blood and body fluids reported to a hotline or to health officials at four dental teaching clinics. The authors used a standard questionnaire to solicit and record data regarding each exposure. During a 63-month period, 428 parenteral exposures to blood or body fluids were documented. Dental students and dental assistants had the highest rates of exposure. Syringe needle injuries were the most common type of exposure, while giving injections, cleaning instruments after procedures and drilling were the activities most frequently associated with exposures.

Accidents, Occupational↗
PubMed1997

Attitudes of physical therapists who possess sports specialist certification.

Physical therapists contemplating sports specialist certification need research-based information to facilitate their decision-making process. The purpose of this study was to investigate the attitudes of physical therapists who have received sports specialist certification. These attitudes encompass the physical therapists' sense of fulfillment and their feelings of satisfaction or dissatisfaction with the certification process. Factors contributing to the therapist's decision to become sports specialist certified have also been investigated. Physical therapists who are sports certified specialists (N = 110) participated in this study. Questionnaires were mailed to the entire population of physical therapists who are sports certified specialists (N = 148). Frequency distributions and percentages were used on qualitative data, and mode was calculated for quantitative data. One hundred ten surveys were returned, for a response rate of 74.3%. Analysis of responses from the subject group suggests that physical therapists feel a high level of satisfaction with their decision to specialize, and that continued professional growth, development, and personal achievement are the major contributing factors in their decision to specialize. Based on these findings, physical therapists appeared to display overall satisfaction in their attitudes toward sports specialist certification. Further research may be warranted to further examine sports certified therapists' attitudes toward the specialization process.

Adult↗
PubMed1996

Embryonic expression of vasoactive intestinal peptide (VIP) and VIP receptor genes.

Vasoactive intestinal peptide (VIP) exhibits pronounced effects on the growth rate of cultured mouse embryonic day (E) 9.5 embryos and acts in tissue culture as a potent glial mitogen and neuron survival factor. However, previous studies using immunohistochemistry or in situ hybridization in the rat have not revealed the presence and location of VIP or VIP mRNA in the early developing embryo CNS. Using a sensitive in situ hybridization assay with a 33P-labeled riboprobe, we show here that the VIP gene is expressed at least as early as E11 in the mouse hindbrain. Northern blot analysis on RNA from brain dissected from mouse embryos beginning at E14 confirmed that a correct-size mRNA for VIP was present by E14 and at later time points. Expression of the VIP2 receptor gene was also detected by northern analysis in E14 mouse brains. These studies support the hypothesis that VIP produced by the embryo exerts important effects on embryonic nervous system development.

Animals↗
PubMed1994

Isolation and characterization of XE169, a novel human gene that escapes X-inactivation.

Overlapping cDNA clones for a novel human X-linked gene, XE169, have been isolated and characterized. The composite cDNA sequence comprises 5910 bp (or 5901 bp) plus a poly(A) tail, with a 531 bp 5' and 696 bp 3' untranslated regions. The sequence represents a full-length or near full-length cDNA for the gene since Northern blot analysis reveals only a single prominent band approximately 6 kb in size. Alternative splicing generates two distinct transcripts either containing or missing a stretch of nine nucleotides in the XE169 single large open reading frame, which in turn predict two XE169 protein isoforms composed of 1557 and 1560 amino acids, respectively. Southern hybridization analysis of a panel of human-mouse somatic cell hybrids containing various portions of translocated human X chromosomes has assigned XE169 to the proximal half of the X short arm between Xp21.1 and the centromere. XE169 is expressed in multiple human tissues tested and homologous sequences exist on the human Y chromosome and in the genomes of five other eutherian mammals examined. RT-PCR analysis of somatic cell hybrids containing either an active or an inactive human X chromosome on a rodent background demonstrated that XE169 escapes X-inactivation.

Alternative Splicing↗
PubMed1994

Detection of mutations and polymorphisms using fluorescence-based dideoxy fingerprinting (F-ddF).

We have adapted the dideoxy finger-printing (ddF) technique for detecting DNA sequence variants to fluorescence detection (F-ddF) using an Applied Biosystems Model 373A DNA Sequencer equipped with GENESCAN 672 software and an external temperature control device. The fingerprints can be precisely aligned using an internal standard run in the same lanes. This facilitates location and characterization of mobility changes resulting from sequence variants. As compared to fluorescence detected single-strand conformation polymorphism analysis (F-SSCP), F-ddF is equally efficient for detection of sequence variants, and it offers additional advantages. These include information regarding location of the sequence variation, greater reliability for distinguishing one sequence variant from another and the capacity to generate large PCR fragments and analyze them in smaller subsegments. Read length and overall quality of data from F-ddF are sequence-dependent when Taq DNA polymerase is used, but reducing terminator concentration can extend read length. The strengths and weakness of F-ddF and F-SSCP are different. Thus F-ddF may work better in a given situation than F-SSCP and vice versa. A strategy for using F-ddF to circumvent limitations of F-SSCP is described.

Animals↗
PubMed1993

Efficacy of fluorescence-based PCR-SSCP for detection of point mutations.

We assessed the efficiency of fluorescence-based PCR single-strand conformation polymorphism analysis (PCR-SSCP) using an automated DNA sequencer and analysis software. We evaluated 48 point mutations in a 191-bp stretch of mouse beta-globin. The mutations included 10 transversions and 38 transitions; and both types of mutation were compared at six different locations in the PCR fragment. Mobilities of the red dye-labeled internal standard fragments were non-proportional to size but highly reproducible and were used to normalize or correct minor differences in apparent electrophoretic mobility between lanes. Forty-six of forty-eight mutants (96%) were distinguished from wild type when run in separate lanes using one set of conditions. Co-electrophoresis of wild type and mutant in the same lane resolved 100% of 45 mutants from wild type. Under conditions of this study, the magnitude of mobility shifts resulting from the globin mutations were largely determined by position of the mutation, rather than by the nature of the substitution (transition vs. transversion). However, examination of paired mutations at the same position revealed that some substitutions cause greater mobility shifts than others.

Animals↗
PubMed1992

Physical mapping of loci in the distal half of the short arm of the human X chromosome: implications for the spreading of X-chromosome inactivation.

The relative order of 11 loci in the distal half of the short arm of the human X chromosome was examined using a panel of somatic cell hybrids containing structurally rearranged X chromosomes. The results show that the gene for phosphoribosylpyrophosphate synthetase 2 (PRPS2) is located between ZFX (zinc finger protein, X-linked) and STS (steroid sulfatase). The results also confirm the localization of ZFX distal to POLA (alpha-DNA polymerase). Previous studies have shown that STS and ZFX escape X-inactivation whereas POLA undergoes inactivation. Evaluation of PRPS2 expression in somatic cell hybrids containing inactive human X chromosomes showed that PRPS2 undergoes X-inactivation. These results provide further evidence for interspersion of loci that do and do not undergo X-inactivation on the human X chromosome.

Arylsulfatases↗
PubMed1992

Directed isolation of human genes that escape X inactivation.

Existing methodologies have been combined to produce a directed approach to the isolation of human genes that escape X inactivation. A mouse-human somatic cell hybrid line was established that has an inactive X as its only human chromosome, and nuclear RNA from this cell line was used to construct a cDNA library. Transcribed human sequences were isolated by screening the library with labeled human DNA. The corresponding genomic sequences were isolated in phage or cosmid clones, and exons were identified by detection of transcripts on northern blots. By these means three human loci have been identified that contain genes expressed from an inactive X chromosome. Fluorescence in situ hybridization has been used to map these genes to Xp21.1-22.1, Xp22.1-22.2, and terminal Xp/Yp. One of the three genes (XE45) corresponds to the ZFX gene, while the other two genes (XE7 and XE59) represent novel cloned sequences. Physical and genetic evidence indicate that XE7 is a newly identified pseudoautosomal gene.

Animals↗
PubMed1992

Isolation and characterization of a yeast artificial chromosome (YAC) contig around the human steroid sulfatase gene.

The region surrounding the steroid sulfatase (STS) locus on Xp22.3 is of particular interest since it represents a deletion hot spot, shares homology with the proximal long arm of the Y chromosome (Yq11.2), and contains genes for several well-described X-linked disorders. Here we describe yeast artificial chromosomes (YACs) covering 450 kb around the STS gene. Eight YAC clones were isolated from a human YAC library. Their STS exon content was determined and the overlap of the clones characterized. Two of the YAC clones were found to contain the entire STS gene. The most proximal and the most distal ends of the YAC contig were cloned but neither of them crossed the breakpoints in any of the previously described patients with entire STS gene deletions. This is consistent with deletions larger than 500 kb in all these patients. One of the YAC clones was found to contain sequences from the STS pseudogene on Yq11.2. Two anonymous DNA sequences, GMGXY19 and GMGXY3, previously mapped in the vicinity of the STS locus, were found within the YAC contig and their assignment with respect to the STS locus was thus possible. This contig is useful for the overlap cloning of the Xp22.3 region and for reverse genetic strategies for the isolation of disease genes in the region. Furthermore, it may provide insight into the molecular mechanisms of deletion and translocation events on Xp22.3 and in the evolution of sex chromosomes.

Arylsulfatases↗
PubMed1992

Isolation of a new gene from the distal short arm of the human X chromosome that escapes X-inactivation.

A gene, designated GS1, was identified by its association with a CpG island approximately 100 kb telomeric to the steroid sulfatase (STS) locus on the distal short arm of the human X chromosome. Both cDNA and genomic clones of the GS1 gene have been isolated and characterized. The cDNA clone detects a 2.3 kb transcript in human placenta and fibroblasts, and may encode a protein of 214 amino acid residues. Although sequences homologous to GS1 cDNA are present on chromosomes 1, 20, X, and Y, the functional GS1 gene is on the X chromosome. The GS1 gene appears to be non-essential, as there are no obvious clinical differences between STS deficient patients with point mutations in the STS gene, and patients with a deletion of the STS and GS1 genes. The GS1 gene is expressed from mouse-human cell hybrids containing active or inactive human X chromosomes, indicating that it escapes X inactivation. Characterization of GS1 genomic clones revealed that the gene consists of 4 exons spanning over 105 kb, with its transcriptional direction opposite to that of the STS gene. The isolation and characterization of a new gene which escapes X inactivation from distal Xp is of interest as it adds to our understanding of the structural organization of the human X chromosome and may help in providing clues regarding the mechanism of X-inactivation.

Amino Acid Sequence↗
PubMed1992

M NET: a statewide referring physician computer network.

M NET, the Referring Physician Computer Network, is a joint project between the University of Michigan Medical Center (UMMC) and IBM. A graphical user interface was developed to allow referring physicians easy access to a variety of patient, clinical, and institutional data. File transfer mechanisms were created and current clinical database files and programs were enhanced and restructured to facilitate remote data transmission. M NET is currently installed in referring physician office sites across the state, with additional physician sites identified and program enhancements under development.

Computer Communication Networks↗
PubMed1988

The human X-linked steroid sulfatase gene and a Y-encoded pseudogene: evidence for an inversion of the Y chromosome during primate evolution.

The mammalian X and Y chromosomes are thought to have evolved from a common, nearly homologous chromosome pair. Although there is little sequence similarity between the mouse or the human X and Y, there are several regions in which moderate to extensive sequence homologies have been found, including, but not limited to, the so-called pseudoautosomal segment, in which X-Y pairing and recombination take place. The steroid sulfatase gene is in the pseudoautosomal region of the mouse, but not in man. We have cloned and characterized the human STS X-encoded locus and a pseudogene that is present on the long arm of the Y chromosome. Our data in humans and other primates suggest that there has been a pericentric inversion of the Y chromosome during primate evolution that has disrupted the former pseudoautosomal arrangement of these genes. These results provide additional insight into the evolution of the sex chromosomes and into the nature of this interesting portion of the human genome.

Animals↗
PubMed1988

Only tissue-type plasminogen activator is secreted by immature bovine Sertoli cell-enriched cultures.

Two molecular variants of plasminogen activator (PA): urokinase (uPA) and tissue-type plasminogen activator (tPA), have been reported to be synthesized in the rat testis. Data obtained in this study using monospecific antibodies raised against uPA and tPA in immunoblotting and bioimmunoassay protocols consistently demonstrate that only tPA (and not uPA) is synthesized by bovine Sertoli cell-enriched cultures, and is induced by bovine FSH. Zymographic analysis of conditioned medium on gels containing plasminogen and casein showed a dominant PA proteolytic band (72 kDa) which co-migrated with human tPA. A proteolytic band (43 kDa), which was also secreted by FSH-stimulated cells, was not present when protection was afforded from auto-proteolysis by aprotinin, and was therefore concluded to be a proteolytic fragment of tPA, and not uPA.

Animals↗
PubMed1987

Chromosomal assignment of the murine Gi alpha and Gs alpha genes. Implications for the obese mouse.

The G protein family of transmembrane signaling molecules includes Gs and Gi, the stimulatory and inhibitory regulators of adenylate cyclase. These and other characterized G proteins are comprised of beta, gamma, and alpha chains, the latter being the most variable among the proteins and thus serving to distinguish them. Previous results (Begin-Heick, N. (1985) J. Biol. Chem. 260, 6187-6193) suggested that the autosomal recessive mouse mutation obese (ob), which results in an abnormal response of adipose tissue to lipolytic hormones, is due to a defect in the gene coding for the alpha chain of Gi. In order to test this hypothesis we used a cloned cDNA probe representing murine Gi alpha mRNA in conjunction with a panel of Chinese hamster-mouse somatic cell hybrids segregating mouse chromosomes to map the Gi alpha gene in the mouse. In addition, we used a cDNA probe representing the murine Gs alpha gene to a specific mouse chromosome. Our results indicate that the Gi alpha locus maps to mouse chromosome 9, while Gs alpha is localized to region 2E1-2H3 of mouse chromosome 2. Localization of the Gi alpha gene to chromosome 9 excludes this gene as a site of the ob mutation, since the ob locus maps to chromosome 6. Furthermore, our findings indicate that certain members of the murine G protein alpha gene family have dispersed to different chromosomes since diverging from a common ancestral gene.

Animals↗