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J Lindsey

Publications and source records attributed to J Lindsey.

27 records · Page 2Linked to original sources
PubMed1992

Recombination between rhodopsin and locus D3S47 (C17) in rhodopsin retinitis pigmentosa families.

Autosomal dominant retinitis pigmentosa (adRP) has shown linkage to the chromosome 3q marker C17 (D3S47) in two large adRP pedigrees known as TCDM1 and adRP3. On the basis of this evidence the rhodopsin gene, which also maps to 3q, was screened for mutations which segregated with the disease in adRP patients, and several have now been identified. However, we report that, as yet, no rhodopsin mutation has been found in the families first linked to C17. Since no highly informative marker system is available in the rhodopsin gene, it has not been possible to measure the genetic distance between rhodopsin and D3S47 accurately. We now present a linkage analysis between D3S47 and the rhodopsin locus (RHO) in five proven rhodopsin-retinitis pigmentosa (rhodopsin-RP) families, using the causative mutations as highly informative polymorphic markers. The distance, between RHO and D3S47, obtained by this analysis is theta = .12, with a lod score of 4.5. This contrast with peak lod scores between D3S47 and adRP of 6.1 at theta = .05 and 16.5 at theta = 0 in families adRP3 and TCDM1, respectively. These data would be consistent with the hypothesis that TCDM1 and ADRP3 represent a second adRP locus on chromosome 3q, closer to D3S47 than is the rhodopsin locus. This result shows that care must be taken when interpreting adRP exclusion data generated with probe C17 and that it is probably not a suitable marker for predictive genetic testing in all chromosome 3q-linked adRP families.

Chromosome Mapping↗
PubMed1991

In vivo loss of telomeric repeats with age in humans.

Telomeric DNA in the skin cells of 21 human subjects aged between 0 and 92 years was quantified by determining the length of the telomeric smear and the relative amount of TTAGGG repeat sequences. Both telomere length and quantity of telomeric repeat sequences were found to decrease significantly with age. Telomere loss has previously been postulated to be a caused of cell senescence.

Adolescent↗
PubMed1990

The structure of a subterminal repeated sequence present on many human chromosomes.

All telomeres which have been studied consist of an array of simple G/C rich repeats. Human telomeres were shown to share sequence similarity with those of lower eukaryotes by cross-hybridization and human telomeric sequences have been cloned by complementation of telomere function in yeast. Analysis of human telomeric sequences cloned in this way is described here. The terminal part of the cloned human telomeric DNA consists of an array of simple repeats, principally of the sequence TTAGGG and derivatives. The very terminal part consists of yeast-type telomeric repeats which suggests that the human telomeric sequences have acted as a primer for the addition of additional telomeric repeats in the yeast. Subterminal sequences are shared between a number of clones and in situ data shows that these subterminal sequences are present at several different chromosomal ends. Related sequences are present at internal as well as telomeric positions. Differences in the hybridization patterns of subterminal sequences in somatic compared to germ-line tissues are described which indicate differential modification of these sequences during development.

Base Composition↗
PubMed1987

Genome interactions which influence DNA palindrome mediated instability and inviability in Escherichia coli.

The interaction of three factors determine the detrimental effect of a palindromic DNA sequence in Escherichia coli cells. The first is the nature of the palindrome (its length, extent of central asymmetry and perhaps its base sequence), the second is the genotype of the host cell and the third is the replicon within which it is located. In this paper we extend the genetic and physical characterization of lambda bacteriophages carrying a palindrome of approximately 560 base pairs. We also show that a palindrome of approximately 110 base pairs which can be cloned in a plasmid cannot be cloned in a phage M13 derivative. These observations are relevant to the choice of vectors used in the cloning of eukaryotic DNA containing palindromic sequences.

Bacteriophage lambda↗
PubMed1986

In vivo loss of supercoiled DNA carrying a palindromic sequence.

Interest in the fate of long palindromic DNA sequences in E. coli has been kindled by the observation that their inviability is overcome in recBC sbcB strains and that these hosts permit the construction of DNA libraries containing long palindromic sequences present in the human genome. In this paper we show that a reduction in the level of intracellular supercoiled DNA occurs as the result of the presence of a 530 bp palindrome in bacteriophage lambda. This reduction occurs in Rec+ and recA strains but not in strains lacking exonucleases V and I (recBC sbcB). However, the DNA must be active (not repressed) for this reduction to be observed, since it is not seen in a Rec+ host lysogenic for phage lambda. These results argue against two hypotheses: firstly, that the palindrome causes inviability solely by interfering with packaging, and secondly, that it does so solely by interfering with recombination. Conversely, these results suggest that a feature of active monomeric DNA (probably its replication) is involved in inviability.

Bacteriophage lambda↗
PubMed1985

Polycythemia rubra vera and conjunctival vascular congestion.

A case of primary polycythemia is reported. The patient presented with bilateral, diffuse, painless engorgement of the palpebral and bulbar conjunctiva which improved dramatically following phlebotomy. Polycythemia, because of increased blood viscosity, can result in ocular, neurologic, and peripheral vascular disease.

Biopsy↗
PubMed1979

Control of perinatal infection by traditional preventive measures.

A 9-year review of nosocomial infections occurring in the department of obstetrics and gynecology of a major teaching hospital demonstrated the dramatic effect of strict asepsis and isolation on postoperative infection rates. With rigidly enforced preventive measures and without the use of prophylactic antibiotics, the rates of wound infection and endometritis and the relative prevalence of gram-negative aerobic organisms cultured from these infections could be reduced substantially. The role of anerobes in these infections was not established, since adequate techniques for the accurate diagnosis of anaerobic infection were not available at the time of this study. The relative importance of the numerous infection-control measures used is unclear. It is apparent, however, that by implementing all traditional methods of asepsis, virtually all types of nosocomial infection could be controlled, and the increased prevalence of gram-negative infections observed during the past decades could be reversed.

Asepsis↗