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Biomedical subjects

C Glover

Publications and source records attributed to C Glover.

30 records · Page 2Linked to original sources
PubMed1996

Analysis of meningococcal serogroup C-specific antibody levels in British Columbian children and adolescents.

The effects of age, sex, and possible prior exposure to serogroup C meningococci on group C-specific antibody levels (total and functional) were examined in 2- to 19-year-olds just before and 1 and 12 months after immunization with divalent (groups A + C) meningococcal capsular polysaccharide vaccine. Only age was found to have a significant effect on antibody levels. At 1 month, only 50% of 2- to 6-year-olds had detectable serum bactericidal antibody, in contrast to 84.1% and 96.3% of 9- to 12- and 13- to 19-year-olds respectively. By 12 months, only 20%, 40.9%, and 53.8% of subjects in these age groups had serum bactericidal antibody, suggesting that current meningococcal C polysaccharide vaccines provide only short-term protection. However, the drop in total specific antibody levels (by EIA) was less pronounced. Persistence of antibodies detectable by EIA (but not serum bactericidal antibodies) suggests that this vaccine may also give rise to antibodies of low affinity or directed to nonfunctional (nonprotective) epitopes (or both).

Adolescent↗
PubMed1996

Relation between tumor size, quality of life, and survival in patients with colorectal liver metastases.

PURPOSE AND METHODS: This study assessed the relationship between survival, tumor size, and quality of life (QoL; Rotterdam Symptom Checklist [RSC], Hospital Anxiety and Depression Scale [HAD], and Sickness Impact Profile [SIP]) in 50 patients with colorectal liver metastases (CLM). RESULTS: Physical symptom score (RSC) was a stronger survival predictor than tumor size measured on computed tomographic (CT) scan. The best model for predicting survival included QoL questions about diarrhea, eating, restlessness, and ability to work and sleep. The only clinically measured variable included in this best survival prediction model was serum alkaline phosphatase level. This is the first study to show that QoL indices predict survival in CLM. The findings suggest that differences in tumor products and not just in tumor size could influence patient fitness and survival in CLM. Such differences are more accurately estimated by QoL assessment than measurement of tumor size. CONCLUSION: QoL provides a better survival estimate than measurement of tumor size and could be used as a surrogate end point for survival in treatment trials.

Aged↗
PubMed1992

Does cancer survival differ for older patients?

The relation of age to 5-year relative survival rates was examined for leading sites of cancer resulting in death among 127,554 patients; data from 1978 to 1982 were studied for four areas of the Surveillance, Epidemiology and End Results program of the National Cancer Institute. Overall and stage-stratified relative survival rates declined with advancing patient age for cancer of the lung, prostate, pancreas, bladder, oral cavity, uterus, cervix, ovary, and large bowel (women only). In men, this trend was not explained by age differences in stage of diagnosis, whereas, among women, age was associated with more advanced disease for most sites examined. Although overall survival rates were lower in black patients compared with white patients, the age-survival and age-stage trends were similar in the two racial groups.

Black or African American↗
PubMed1981

Rous sarcoma virus infection of synchronized cells establishes provirus integration during S-phase DNA synthesis prior to cellular division.

Synchronized chicken embryo fibroblasts, prepared by addition of serum to stationary cells arrested in Go, were exposed to the Prague strain of Rous sarcoma virus. At different times during the cell cycle, high molecular weight DNA was prepared from infected cells and examined for the presence of newly integrated viral DNA sequences. The results demonstrate that newly integrated viral sequences were first detected during S-phase DNA synthesis 9 hr after infection. The presence of colchicine prevented cellular division and delayed the appearance of progeny virus but it did not affect the appearance of viral specific DNA in the high molecular weight fraction of cellular DNA. Our results indicate that provirus integration, occurring during S-phase DNA synthesis, does not require cell division. Previous experiments have demonstrated that Rous sarcoma virus infection of chicken embryo fibroblasts requires cell division to initiate viral RNA synthesis and the production of progeny virus. The findings presented in this report support the hypothesis that division of the infected cells is required for an event that controls viral expression at the level of the integrated provirus.

Animals↗
PubMed1981

Independent expression of avian sarcoma virus in doubly infected chicken embryo fibroblasts.

Infection of a chicken cell with avian sarcoma virus requires division of the infected cell before synthesis of infectious progeny is initiated. This requirement for a cell division for the complete expression of avian sarcoma virus has been examined further with chicken embryo fibroblasts infected with two distinct viruses. Chicken cells infected with and producing a mutant of Rous sarcoma virus temperature sensitive for transformation (tsLA24PR-A) were arrested in G0 by depletion of serum factors from growth medium. These stationary cells continued to produce infectious progeny in the absence of further cell division. Superinfection of the stationary cells with the wild-type Prague strain of Rous sarcoma virus (PR-RSV-C) produced a stable double infection in these cells. Progeny of the superinfecting PR-RSV-C, however, were not detected until these cells underwent division after stimulation with fresh serum-containing medium. The addition of colchicine to these serum-stimulated cells, although not affecting production of the tsLA24PR-A, inhibited the appearance of progeny of the superinfecting PR-RSV-C. These experiments indicate that each avian sarcoma virus infection of a chicken embryo fibroblast requires division of the infected cell for production of that virus regardless of whether or not the cell is already producing a similar virus. The results suggest, therefore, that the requirement for a cell division represents a requirement for an event that controls virus expression in a "cis-acting" fashion specific for the provirus.

Animals↗
PubMed1981

Clonal analysis of the integration and expression of endogenous avian retroviral DNA acquired by exogenous viral infection.

Rous-associated virus-0 is one of several endogenous avian retroviruses that are transmitted vertically and that can be isolated from different inbred lines of chickens. These viruses, referred to here as induced-leukosis viruses bearing a subgroup E glycoprotein (ILV-E), are all closely related. Clonal populations of fibroblasts from line 15B and line 100 inbred chickens have been examined for the presence and expression of exogenously acquired ILV-E sequences. Restriction enzyme analysis of uniform populations of line 15B fibroblasts, prepared by cloning cells either before or after infection with ILV-E, indicates that viral sequences were inserted at multiple sites within the cell genome. Analysis of 49 clonal populations of line 100 fibroblasts containing between one and five copies of exogenous ILV-E sequences demonstrated that each clone was characterized by a unique set of viral DNA insertions within the cell genome. The expression of the exogenous ILV-E sequences within these fibroblast clones was examined by using reverse transcriptase activity as a measure of virus production. Some clones produced an amount of virus equivalent to that produced by an equal number of the uncloned ILV-E-infected parental fibroblasts. Other clones produced 5- to 10-fold less virus. Still other clones produced no detectable virus at all. Among nine clones derived from cells containing a single copy of the ILV-E provirus, the level of virus production differed more than 100-fold. DNA from these clones was analyzed with several different restriction endonucleases to characterize the location and arrangement of the ILV-E sequences. All nine clones consisted of cells that appeared to contain a complete provirus inserted (i) in a different site within the cellular DNA and (ii) in an orientation that was colinear with the viral genomic RNA. It was observed that several cleavage sites potentially affected by methylation were equally available for cleavage in all clones regardless of the level of viral production.

Animals↗
PubMed1980

Low-molecular-weight RNAs and initiation of RNA-directed DNA synthesis in avian reticuloendotheliosis virus.

The small RNAs of avian reticuloendotheliosis virus (REV) were analyzed by two-dimensional polyacrylamide gel electrophoresis and compared with those of murine leukemia virus and avian sarcoma virus. Although there were some similarities among the three virus types, the patterns of small RNAs were distinct. By characterizing the small RNA which is most tightly associated with REV genome RNA and which can be labeled in limited DNA synthesis reactions, the primer for REV reverse transcription was identified as tRNAPro. This is consistent with previous reports that REV is more closely related to retroviruses of mammalian origin than to other avian viruses. In contrast, REV strong-stop complementary DNA is longer than any previously characterized strong-stop products of avian or mammalian retroviruses. The REV group may, therefore, have been derived from an as yet unidentified mammalian type C virus.

Avian Sarcoma Viruses↗
PubMed1980

tRNA's and priming of RNA-directed DNA synthesis in mouse mammary tumor virus.

The low-molecular-weight RNAs of mouse mammary tumor virus (MuMTV) were examined by two-dimensional acrylamide gel electrophoresis. Unlike other retroviruses, MuMTV was found to contain only two major fractions of tRNA. These have been fully characterized and shown to correspond to the published sequences for tRNA1+2Lys and tRNA3Lys. By determining which of these tRNA's was most tightly associated with the MuMTV genome and which of them acquired label from [alpha-32P]deoxynucleoside triphosphates in limited DNA synthesis reactions, we identified tRNA3Lys as the primer for MuMTV reverse transcription in vitro. tRNA3Lys does not share any unusual sequence feature with the other previously characterized retrovirus primers, tRNATrp and tRNAPro.

Base Sequence↗
PubMed1979

Differences between the endogenous and exogenous DNA sequences of Rous-associated virus-O.

DNA sequences related to the endogenous retrovirus of chickens, Rous-associated virus-O (RAV-O), have been examined using site-specific DNA endonuclease analysis of cellular DNA derived from line 15 and line 100 chickens. Individual embryos from both inbred lines were used as a source of embryonic fibroblasts from which cellular DNA was isolated. Analysis of DNA containing either endogenous RAV-O sequences alone or both endogenous and exogenous RAV-O sequences produced identical patterns of RAV-O-specific DNA fragments after digestion with the endonucleases Eco RI, Hind III, BgI II, Bam HI or Xho I. Similar analysis with endonucleases Hinc II or Hha I, however, produced several RAV-O-specific DNA fragments which were derived from cellular DNA containing both endogenous and exogenous RAV-O sequences but not from cellular DNA containing only endogenous sequences. Although some differences exist between the DNA fragments specific for the endogenous viral sequences of line 15 and line 100 cellular DNA, the DNA fragments specific for the exogenous viral sequences were identical between the two inbred lines. Cleavage of an unintegrated linear RAV-O DNA molecule with Hinc II or Hha I produced DNA fragments identical to those specific for the exogenously acquired RAV-O provirus. This suggests that these characteristic fragments contain no cellular DNA. The potential DNA junction fragments containing both viral and cellular DNA, identified after analysis of DNA that contains both endogenous and exogenous viral sequences, were identical to those observed after analysis of DNA containing only endogenous viral sequences. These results support the following conclusions. First, exogenous proviral sequences are integrated into chicken cell DNA following an interaction between viral and cellular DNA that is specific with respect to the virus and nonspecific with respect to the cell. Second, both the free linear RAV-O DNA intermediate and the newly integrated exogenous provirus contain specific endonuclease sites that are not found in endogenous RAV-O DNA sequences. These results suggest that the formation of the exogenous DNA provirus involves specific alteration of the endogenous viral DNA sequences before reinsertion of the sequences as the exogenous RAV-O DNA provirus. It is possible that newly integrated exogenous RAV-O sequences are characterized by specific differences in the pattern of base methylation and a limited sequence arrangement.

Animals↗