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Biomedical subjects

C Jones

Publications and source records attributed to C Jones.

At least 649 records · Page 36Linked to original sources
PubMed1982

Genetic fine-structure mapping in human chromosome 11 by use of repetitive DNA sequences.

A method is described for mapping of the DNA fragments of a human chromosome produced by restriction enzyme treatment of the total DNA from a hybrid cell containing a single human chromosome. The method involves production and selection of somatic cell mutants containing deletions of the human chromosome and application of a hybridization probe consisting of an individual member copy of a repetitive human DNA family. A linear map has been constructed of 19 marker DNA fragments and 5 immunological and biochemical markers on human chromosome 11, selected as a model chromosome for these studies. This approach appears to be widely applicable, is independent of cytogenetic analysis, promises to be capable of revealing the existence of rearrangements as well as deletions, appears to be amenable to further increase in resolving power, and offers potential application in various human genetic problems.

Cell Line↗
PubMed1982

Neuropsychological functioning in opiate addicts.

Neuropsychological functioning in opiate addicts has been infrequently studied and results have been contradictory. In the current study, 72 opiate addicts, 60 epileptics, and 29 demographically comparable normals were tested using a brief neuropsychological test battery. Few significant differences were noted between the performance of addicts and the subjects in comparison groups, and these were in a direction suggesting better functioning in the addict sample. Follow-up re-evaluation of addicts showed stability in most measures but significant improvement in measures of intelligence quotient, verbal fluency, and new associative learning. Performance on neuropsychological tests was shown to be independent of current or past levels of opiate use and to be of little prognostic significance in relation to treatment outcome. In contrast, a comparatively strong association was noted between measures of neuropsychological functioning and educational achievement.

Adult↗
PubMed1982

Somatic cell genetic approaches to Down's syndrome.

Somatic cell genetic analysis of mutants of Chinese hamster ovary cells with deficient purine synthesis and of hybrids between these mutants and human cells is described. Data are presented substantiating that two genes for enzymes of purine synthesis, AdeC and AdeG, can be coordinately regulated in mammalian cells. Analysis of a human-hamster hybrid cell, Ade C/21, which contains a normal complement of hamster chromosomes and human chromosome 21 as its only human genetic component recognizable by electrophoretic and immunogenetic techniques demonstrates that genes associated with the presence of human chromosome 21 and required for the synthesis of specific polypeptides and specific human lethal cell surface antigens can be detected in these hybrids.

Animals↗
PubMed1982

A survey of DNA repair incision activities after ultraviolet irradiation of a range of human, hamster, and hamster-human hybrid cell lines.

We describe a rapid and simple assay for DNA damage and repair in mammalian cells, based on the partial unwinding of nicked DNA in alkali, and involving transfer of this DNA to nitrocellulose and the digestion of single-stranded DNA with S1 nuclease, all steps taking place on tissue-culture chamber slides. Direct breakage of DNA by ionizing radiation has been examined, and we have developed a standard procedure for measuring enzymic breakage of DNA as an index of excision-repair capacity following ultraviolet irradiation. We report a wide range of repair capacities among various hamster and human cell lines, with considerable overlap between the two species. Hybrids between hamster and human cells tend to display repair activity characteristic of the hamster parent.

Animals↗
PubMed1981

Properties of ribosomes centrifuged in metrizamide gradients.

The banding of ribonucleoproteins in metrizamide has been characterised using yeast ribosomes as a model system. Metrizamide does not dissociate ribosomes but it can facilitate the loss of loosely bound proteins. The buoyant density of fixed ribosomes in metrizamide gradients increases dramatically in the presence of low concentrations of Mg2+, whilst high Mg2+ concentrations give rise to multiple bands of higher density. These phenomena can be explained in terms of the binding of Mg2+ to high and low affinity sites as proposed for Escherichia coli ribosomes.

Cell Fractionation↗
PubMed1981

The family meets the hospital. Predicting the family's perception of the treatment program from its problem solving style.

A family's perception of a treatment program may determine whether ir becomes productively engaged or destructively withdrawn. A theory of family types, in conjunction with a standardized laboratory problem solving procedure, was used to predict the nature of families' shared perceptions of a psychiatric ward. The individual and shared perceptions of thirty families were determined by means of a specially designed Q-sort. Two dimensions of problem solving behavior successfully predicted significant differences between families in their shared perceptions. Configuration, or the family's capacity to derive effective solutions in the laboratory, predicted the subtlety to their perception of the ward. Coordination, or the capacity of family members to dovetail their problem solving effort with one another, predicted the family's sense of comfort and engagement in the ward setting.

Adolescent↗
PubMed1981

Father to infant attachment: effects of early contact and characteristics of the infant.

Fifty-one father-infant dyads were studied at 24-72 hours of age and at 1 month to determine the effects of early contact, sex, and irritability of the infant on fathers' perceptions and behaviors. Irritability was measured by a factor of four items from the Brazelton Neonatal Assessment Scale administered at 24-72 hours. Fathers who held their infants in the first hour of life demonstrated more nonverbal behavior toward their infants during on observation at 1 month than those who did not have this early contact. Fathers interacted more verbally with girls than with boys at 1 month. A sex and irritability interaction effect was found in fathers' perception of high-irritability boys and low-irritability girls. Fathers also reported more frequent care-taking of high-irritability infants of both sexes than of low-irritability infants.

Adult↗
PubMed1981

Two-dimensional electrophoresis of human-CHO cell hybrids containing human chromosome 11.

Two-dimensional electrophoresis-electrofocusing with polyacrylamide gels is described in which the pattern of peptide spots obtained from hybrid cells of CHO containing the single human chromosome 11 are compared with those from the hybrid which has undergone reversion so as to lose this chromosome. At least eight distinct spots unique to the cell containing chromosome 11 have been located on the electrophoretogram. Experiments are described demonstrating applicability of the method to hybrids containing specific deletion mutants of chromosome 11, an approach which makes possible regional mapping of the loci responsible for specific peptides. The methodology appears applicable to study of gene expression under the influence of hormones and other agents and to the comparison of normal and disease situations.

Animals↗
PubMed1981

Assignment of the gene coding for phosphoribosylglycineamide formyltransferase to human chromosome 14.

Purine-requiring Chinese hamster ovary cell auxotrophs of the complementation class ade-E were hybridized with various human cells, and hybrids were isolated under selective conditions in which the retention of the complementing gene on the human chromosome is necessary for survival. Synteny analysis in 72 primary and secondary hybrid clones using isozyme, karyotypic, and biochemical methods provides evidence for an assignment of the gene for phosphoribosylglycineamide formyltransferase (GART, EC 2.1.2.2), deficient in ade-E mutants, to human chromosome 14. The importance of this gene assignment to the development of hypotheses regarding the organization, structure, and regulation of genes involved in the same biosynthetic pathway in mammalian cells is discussed.

Acyltransferases↗
PubMed1981

Demonstration, by somatic cell genetics, of coordinate regulation of genes for two enzymes of purine synthesis assigned to human chromosome 21.

A method for determining coordinate genetic regulation is proposed for mammalian cells. The method involves (i) isolation of a set of mutants defective in the relevant pathway; (ii) complementation analysis of these mutants to determine dominance and to categorize the mutants into various different complementation groups; (iii) determination of the biochemical blocks in the mutants; (iv) identification of individual mutants that fail to complement the members of at least two distinct complementation groups that complement each other, such mutants being said to show coordinate regulation of the affected functions; (v) biochemical and reversion analysis of the relevant cell types to confirm the basis for the observed coordinate regulation; (vi) assignment of the individual genes to particular human chromosomes; (vii) mapping of the genes to determine contiguity on the genome; and (viii) examination of the structure of the relevant gene products. This method has allowed the demonstration of coordinate regulation between the gene coding for phosphoribosylglycineamide synthetase [5-phosphoribosylamine:glycine ligase (ADP-forming), EC 6.3.4.13], defective in our Ade-C mutants, and the gene coding for phoshoribosylaminoimidazole synthetase [5'-phosphoribosylformylglycinamidine cyclo-ligase (ADP-forming), EC 6.3.3.1], defective in our Ade-G mutants. Moreover, both genes can be assigned to human chromosome 21. Because at least two genes for purine biosynthesis have now been assigned to chromosome 21, and because patients with trisomy 21 (Down syndrome) show increased levels of serum purines, it may be that cells of these patients overproduce purines and that this overproduction may be relevant to the pathology of the syndrome.

Animals↗