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Biomedical subjects

C Pritchard

Publications and source records attributed to C Pritchard.

At least 73 records · Page 4Linked to original sources
PubMed1989

Comparisons between the self-assessed and observer-assessed presence and severity of colds.

The hypotheses that self-reported symptoms are a valid proxy for physicians' ratings, and that people with different social characteristics may vary in their recognition and evaluation of symptoms, were tested on volunteers attending the MRC Common Cold Unit. Eleven-hundred volunteers assessed the presence and severity of colds at the end of their stay at the unit, using the same two measures as a trained clinical observer (all ratings were double blind). On both measures there was an extremely high correlation between self- and observer-assessments, a finding encouraging for those using self-reports in community surveys. Although this high level of agreement was found within all the age, sex, occupational class and marital status groups, men were significantly more likely than women to over-rate their symptoms in comparison with the clinical observer. No such differences in over-rating were found by age, class or marital status. This finding of a sex difference in the tendency to over-rate physical symptoms is of major significance to theories of illness behaviour, and is particularly convincing because it is based on a double-blind comparison between self-reports and assessments made by a doctor.

Adolescent↗
PubMed1988

MIC2: a human pseudoautosomal gene.

MIC2 and XGR are the only known pseudoautosomal genes in man. MIC2 encodes the 12E7 antigen, a human cell-surface molecule of unknown function. XGR regulates, in cis, the expression of the XG and MIC2 genes. DNA probes derived from the MIC2 locus have been used in the construction of a meiotic map of the pseudoautosomal region and a long range restriction map into the X- and Y-specific chromosome domains. MIC2 is the most proximal marker in the pseudoautosomal region and recombination between the sex chromsomes only rarely includes the MIC2 locus. Our long-range restriction maps and chromosome walking experiments have localized the pseudoautosomal boundary within 40 kilobases adjacent to the 3' end of the MIC2 gene. The same maps have been used to predict the chromosomal location of TDF.

Amino Acid Sequence↗
PubMed1987

Does the use of oral contraception depress DZ twinning rates?

Data based on total births from a geographically defined population with zygosity determined from blood samples and placentation and with data on the use of oral contraceptives routinely collected in early pregnancy showed no association between oral contraceptive use prior to pregnancy in either MZ or DZ twinning. Three mutually exclusive control groups of singletons were used to take account of age, parity and secular trends.

Birth Rate↗
PubMed1987

Recombination between the X and Y chromosomes: implications for the relationship between MIC2, XG and YG.

Three loci affect the levels of expression of the 12E7 antigen on red blood cells: MIC2, the pseudoautosomal structural gene for the 12E7 antigen; XG, an X-linked red cell blood group locus and YG, a polymorphic Y-linked locus. In this report we describe recombination between XG and MIC2 and an exchange between the X and Y chromosomes which included YG. These results have prompted us to propose a new model describing the genetic relationship between the XGa and 12E7 antigens.

Antibodies, Monoclonal↗
PubMed1986

Development of new methods in human gene mapping: selection for fragments of the human Y chromosome after chromosome-mediated gene transfer.

Chromosome-mediated gene transfer (CMGT) can be used to generate fragments of human chromosomes and chromosomal maps can be constructed using these fragments. In previous experiments CMGT techniques have been limited to those regions of the genome which encode biochemically selectable markers. We have extended the regions of the human genome which can be subjected to CMGT methods by employing a cell surface antigen as a selectable marker. These experiments have been facilitated by the discovery that co-transformation of chromosomes with a plasmid bearing a biochemically selectable marker followed by selection for the marker pre-selects for cells which have incorporated chromosomal fragments. The plasmid may also integrate into the donor chromosomes and this provides, in some cases, an additional selectable marker in the chromosome fragment of interest. Using these methods we have isolated for the first time cells containing varying portions of the human Y chromosome.

Cell Line↗
PubMed1986

Perinatal outcomes and related factors: social class differences within and between geographical areas.

This paper makes use of the opportunity provided by comparable obstetric data bases to examine area and social class variations in perinatal outcome and associated factors in areas smaller than those usually reported. Analyses are based on singleton births to primiparous residents in the catchment areas of the Aberdeen Maternity and Neonatal Database (n = 4948) and the Cardiff Births Survey (n = 11893) between 1976 and 1981. The factors considered relate to the obstetric population (height, age, and smoking), obstetric practice (induction and assisted delivery), and perinatal outcome (curtailed gestation, low birthweight, and perinatal death). Our analysis confirms the existence of both area and social class differences and suggests that, except in the case of teenage pregnancy and smoking, the association observed between those factors and area and social class are largely independent of each other.

Female↗
PubMed1981

Replication of parvoviral DNA. I. Characterization of a nuclear lysate system.

We have developed a nuclear lysate system from infected, synchronized cells capable of synthesizing unit-length parvoviral DNA in vitro. It was necessary to supplement the nuclear lysates with the polyamines, spermidine and spermine, to prevent degradation of template and product DNAs. In this system RF, RI, and single-stranded progeny DNAs were synthesized. Label incorporated in viral RF DNA in vivo appeared first in RI DNA and then in single-stranded DNA during incubation in vitro. By sedimentation the product DNAs were identical to those found in infected cells. Their viral identity was confirmed by hybridization. The addition of ribonucleotides, RNase, or alpha-amanitin did not affect parvoviral DNA synthesis in this system. The results with the specific inhibitors of mammalian DNA polymerases, aphidicolin, N-ethylmaleimide, and 2',3'-dideoxythymidine 5'-triphosphate indicated that DNA polymerase alpha was required for synthesis of parvoviral DNA in the nuclear lysates. This requirement was confirmed by experiments with antibody to bovine DNA polymerase alpha.

Animals↗
PubMed1978

Replication of nondefective parvoviruses: lack of a virion-associated DNA polymerase.

We have examined four of the nondefective parvoviruses for an associated DNA polymerase. Virions were purified from neuraminidase-treated infected-cell lysates by isopycnic centrifugation in CsCl or from infected cell material by CaCl(2) precipitation and centrifugation through sucrose into CsCl. Preparations of bovine parvovirus or Kilham rat virus obtained by the former procedure contained DNA polymerase activity but were not free of contaminating cellular proteins. The latter method produced viral preparations free of contaminating cellular proteins, and no DNA polymerase activity was detected in light infectious particles of H-1, LuIII, bovine parvovirus, or Kilham rat virus. Examination of levels of each cellular DNA polymerase in these preparations from each step of both purification procedures revealed that DNA polymerase beta had a greater tendency to copurify with bovine parvovirus and Kilham rat virus than did DNA polymerases alpha or gamma. Disruption of infectious virions obtained by the second purification method with detergents and sonic treatment did not result in the detection of a DNA polymerase activity. The biological activity and purity of each of the four different viruses obtained by the latter procedure were determined by hemagglutination and infectivity assays, polyacrylamide gel electrophoresis, and electron microscopy. In each case, the virions banding at a density of 1.39 to 1.41 g/cm(2) in CsCl were infectious and contained only the virion structural proteins. DNA polymerase activity was not detected in any of these preparations, and we have concluded that a virion-associated DNA polymerase is not required for productive infection with the nondefective parvoviruses.

Animals↗
PubMed1978

Levels of cellular DNA polymerases in synchronized bovine paravovirus-infected cells.

Infection of synchronized bovine fetal spleen cells with bovine parvovirus results in changes in the levels and patterns of DNA polymerases alpha and gamma during the cell cycle. The pattern of DNA polymerase alpha activity closely paralled viral DNA synthesis and the production of progeny virus, and levels, of this enzyme were threefold greater than in mock-infected cells during the period of maximal viral DNA synthesis. DNA polymerase gamma activity remained slightly elevated during viral DNA replication. Levels and patterns of DNA polymerase beta were similar in mock- and virus-infected cells.

Animals↗