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Biomedical subjects

S Christie

Publications and source records attributed to S Christie.

At least 37 records · Page 2Linked to original sources
PubMed1995

A contiguous clone map over 3 Mb on the long arm of chromosome 11 across a balanced translocation associated with schizophrenia.

Forty-nine clones derived by microdissection of a schizophrenia-associated t(1;11)(q42.1;q14.3) breakpoint region have been assigned by somatic cell hybrid mapping to seven discrete intervals on the long arm of human chromosome 11. Eleven of the clones were shown to map to a small region immediately distal to the translocation breakpoint on 11q. A 3-Mb contiguous clone map of this region was established by isolation of corresponding YAC recombinants. The contig was oriented and shown to traverse the translocation breakpoint by FISH and microsatellite marker analysis. This contig will facilitate the isolation of candidate sequences whose expression may be affected by the translocation.

Base Sequence↗
PubMed1995

Malignant syphilis (lues maligna) and concurrent infection with HIV.

BACKGROUND: During the past 2 1/2 years we observed six patients who had a reactive serology for syphilis, of which four developed widespread noduloulcerative and two vesiculonecrotic lesions. The purpose was to report the occurrence of lues maligna, a rare form of secondary syphilis, in five patients infected with the human immunodeficiency virus (HIV) and in one patient with risk factors for infection. METHODS: Tzanck preparations, viral cultures, and skin biopsies were performed to evaluate the etiology of the lesions. RESULTS: Syphilis serology titers ranged from 1:32 to 1:128 and in one instance was as low as 1:8. Such titers can also be found in patients with the latent form of syphilis. Therefore, confirmation of the clinical diagnosis of lues maligna was dependent on skin biopsies that were compatible with secondary syphilis and negative viral studies that excluded varicella, disseminated varicella-zoster or herpes simplex. Lues maligna takes an aggressive course in HIV-infected patients since four of the patients required hospitalization and the two patients who refused to complete treatment, subsequently developed more severe skin and constitutional symptoms. CONCLUSIONS: HIV-infected patients are at risk for developing lues maligna. Despite its malignant presentation, lues maligna lesions respond rapidly to treatment with penicillin. Secondary syphilis should be added to the list of diseases known to be more aggressive in HIV-infected patients.

Adult↗
PubMed1995

Seeding of YACs over regions 1q41-q42.3 and 11q14.3-q23 with microdissection clones.

We describe the use of pooled, region-specific hybridisation probes to screen high-density replica filters of a human genome YAC library. The probes were derived by microdissection of an approximately 30-Mbp region subtending the translocation breakpoint on a der(1)(1;11)(q42.1;q14.3) chromosome. Of 70 microdissection clones used in pools of 4-10, 47 identified a total of 77 YAC recombinants, representing over 50% of the microdissected region. This strategy can easily be adapted to other poorly mapped subchromosomal regions of the human or other mammalian genomes and will provide a solid framework for detailed contig map constructions.

Chromosomes, Artificial, Yeast↗
PubMed1990

Chronic progressive and relapsing neuromyopathy with massive dilatations of endoplasmic reticulum in muscle fibers.

Large intracytoplasmic inclusions arising from the endoplasmic reticulum and nuclear envelope were found in the muscle fibers of a 32-year-old individual with a life-long, chronic and progressive sensory-motor neuropathy. The morphological features of the inclusions were similar to that occasionally reported in the striated muscles in several unrelated conditions as well as to "hyaline" or "colloid" inclusions commonly seen in motor neurons of the brain stem and spinal cord. The chemical nature of the inclusions is not known. Their occurrence in the muscle fibers is probably secondary to chronic denervation.

Adult↗
PubMed1989

Rapid isolation of moderate and highly polymorphic DNA fragments mapping close to WT (Wilms' tumour) and AN2 (aniridia) on chromosome 11.

Genes implicated in the development of Wilms' tumour (WT) and aniridia (AN2) have been localised to a sub-region of band p13 on chromosome 11 by molecular and cytogenetic characterisation of WAGR syndrome patients carrying variable constitutional deletions. Polymorphic markers for the region would be valuable for linkage analysis in the familial forms of both Wilms' tumour and aniridia, as well as for studying somatic rearrangements of chromosome 11 in a variety of tumour types. Here we describe the isolation and characterisation of three frequently polymorphic arbitrary DNA fragments that map proximal to the AN2 and WT loci.

Chromosome Mapping↗
PubMed1989

CpG islands surround a DNA segment located between translocation breakpoints associated with genitourinary dysplasia and aniridia.

We have isolated a DNA segment absent from all the constitutionally deleted chromosomes 11 of our patients with Wilms tumor. This marker separates two balanced translocations that break in band 11p13: the distal one associated with aniridia (AN2), and the proximal one with genitourinary dysplasia (GUD). The GUD breakpoint maps within the smallest region of overlap (SRO) for the Wilms tumor (WT) gene locus, thus strengthening the previous suggestion of an association between Wilms tumor and other abnormalities of the genitourinary system. The 11p13 translocation breakpoint associated with T-cell acute lymphatic leukemia (T-ALL) is centromeric to the SRO and separated from the WT locus by at least one known gene. This region of the human genome (11p13) is rich in CpG islands that potentially identify genes, some of which may be involved in the various phenotypes associated with the WAGR syndrome. This is consistent with the proposition that the majority of human genes are in G-negative bands.

Animals↗
PubMed1988

Hitch-hiking from HRAS1 to the WAGR locus with CMGT markers.

The clinical association of Wilms' tumour with aniridia, genitourinary abnormalities and mental retardation (WAGR syndrome) is characterised cytogenetically by variable length, constitutional deletion of the short arm of chromosome 11, which always includes at least part of band 11p13. HRAS1-selected chromosome mediated gene transfer (CMGT) generated a transformant, E65-6, in which the only human genes retained map either to band 11p13 or, with HRAS1, in the region 11p15.4-pter. Human recombinants isolated from E65-6 were mapped to a panel of five WAGR deletion hybrids and two clinically related translocations. We show that E65-6 is enriched congruent to 400-fold for 11p15.4-pter markers and congruent to 200-fold for 11p13 markers. 'Hitch-hiking' from HRAS1 with CMGT markers has allowed us to define seven discrete intervals which subtend band 11p13. Both associated translocations co-locate within the smallest region of overlap for the WAGR locus, which has been redefined by identifying a new interval closer than FSHB.

Animals↗
PubMed1987

Ten families with fragile X syndrome: linkage relationships with four DNA probes from distal Xq.

We present clinical, cytogenetic, and linkage data of four DNA probes from the terminal long arm of the X chromosome in ten new families with fragile X syndrome. A prior/posterior method of multipoint linkage analysis is employed to combine these results with published data to refine the linkage map of terminal Xq. Ten possible probe/disease orderings were tested. The order with the greatest posterior probability (0.78) of the five loci is 52a-F9-fragile X gene-DX13-St14, although the order with reversal of the positions of 52a and F9 has a posterior probability 0.15. The mean estimates of the distances between the probes and the fragile X gene are 38 cM and 33 cM for the proximal probes 52a and F9, and 8 cM and 12 cM for the distal probes DX13 and St14. Although the current method of choice in the prenatal diagnosis and carrier detection of the fragile X syndrome remains detailed cytogenetic analysis, consideration is given to the potential role of these DNA probes, both singly and in pairs.

Chromosome Banding↗
PubMed1987

Human interstitial retinol-binding protein (IRBP): cloning, partial sequence, and chromosomal localization.

A cloned 2184-bp cDNA coding for human interstitial retinol-binding protein (IRBP) has been isolated and sequenced. The probe hybridized to a 5.2-kb poly(A) RNA from human retinas. Nineteen tryptic peptides (363 amino acids) sequenced and purified from bovine IRBP could be aligned with 86-88% homology to the translated sequence. Two segments approximately 200 amino acids long were found to have a 41% residue identity, suggesting an internal duplication event. This cloned cDNA was used to probe DNA samples from a panel of 29 rodent-human somatic cell hybrids, mapping the structural gene for IRBP to chromosome 10. In situ hybridization suggested a regional localization near the centromere (p11.2----q11.2), although a secondary site of hybridization at q24----25 was also observed.

Amino Acid Sequence↗
PubMed1987

HRAS1-selected chromosome transfer generates markers that colocalize aniridia- and genitourinary dysplasia-associated translocation breakpoints and the Wilms tumor gene within band 11p13.

We show that chromosome-mediated gene transfer can provide an enriched source of DNA markers for predetermined, subchromosomal regions of the human genome. Forty-four human DNA recombinants isolated from a HRAS1-selected chromosome-mediated gene transformant map exclusively to chromosome 11, with several sublocalizing to the Wilms tumor region at 11p13. We present a detailed molecular map of the deletion chromosomes 11 from five WAGR (Wilms tumor/aniridia/genitourinary abnormalities/mental retardation) syndrome patients, three of which are at the limits of cytogenetic resolution but shown here to be molecularly distinguishable and overlapping. We can define ten distinct regions of the short arm of chromosome 11, five of which subdivide band 11p13. We also map two independent 11p13 translocation breakpoints to within the smallest region of overlap defined by the WAGR deletions. The first comes from a patient with familial aniridia, and the second from a patient with Potter facies and genitourinary dysplasia. The close similarities in map location and affected cell lineage for Wilms tumor and genitourinary dysplasia suggest that they may be alternative manifestations of mutation at the same locus.

Animals↗
PubMed1984

The use of cloned Y chromosome-specific DNA probes for fetal sex determination in first trimester prenatal diagnosis.

Prenatal diagnosis by chorion biopsy in the first trimester of pregnancy has advantages over second trimester amniocentesis because diagnosis can be achieved at 9-12 weeks gestation, reducing prenatal anxiety and avoiding the trauma of late abortion. DNA can be prepared from chorionic villus biopsies in sufficient quantity and purity for use in prenatal diagnosis systems using specific DNA probes hybridised to restriction endonuclease digests. DNA probes derived from the Y chromosome have been used to determine fetal sex. The use of such probes means that the chromosomal sex of the fetus can be identified more quickly than by chromosome preparation and more accurately than by sex chromatin staining, and has the additional advantage that the same DNA preparation can be used for other diagnostic tests. A dot hybridisation method has been successfully used to provide even more rapid results than conventional hybridisation to Southern blots of restriction endonuclease digests. There is a risk that Y chromosome-specific DNA probes for sex determination may be subject to error if the parents have extreme Y chromosome variants such as a small or non-fluorescent Y or a Y autosome chromosome translocation. The precise extent to which such chromosome variants may lead to error has been investigated. Even extreme Y chromosome variants totally lacking fluorescence were identified as male by the cloned probes used. However, Y autosome translocations carried by females could cause error if not identified in the parents. The value of the probes has been confirmed provided that parental chromosomes and DNA are examined in parallel with the chorionic biopsy material.

Cloning, Molecular↗
PubMed1983

U1 small nuclear RNA genes are located on human chromosome 1 and are expressed in mouse-human hybrid cells.

The majority, and perhaps all, of the genes for human U1 small nuclear RNA (U1 RNA) were shown to be located on the short arm of human chromosome 1. These genes were mapped by Southern blot analysis of DNA from rodent-human somatic cell hybrids, using the 5' region of a human U1 RNA gene as a human-specific probe. This probe hybridized to DNA fragments present only in digests of total human DNA or to the DNAs of cell lines which contained human chromosome 1. The major families of human U1 RNA genes were identified, but some human genes may have gone undetected. Also, the presence of a few U1 RNA genes on human chromosome 19 could not be ruled out. In spite of the lack of extensive 5'-flanking-region homology between the human and mouse U1 RNA genes, the genes of both species were efficiently transcribed in the hybrid cells, and the U1 RNAs of both species were incorporated into specific ribonucleoprotein particles.

Animals↗