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Biomedical subjects

D Gallahan

Publications and source records attributed to D Gallahan.

32 records · Page 2Linked to original sources
PubMed1991

Long-term in vivo expression of genes introduced by retrovirus-mediated transfer into mammary epithelial cells.

Nonimmortalized mouse mammary epithelial cells expressing Escherichia coli beta-galactosidase from a murine amphotropic packaged retroviral vector were injected into the epithelium-divested mammary fat pads of syngeneic mice. Mammary glands formed from the injected mammary epithelial cells contained ductal and lobular cells, both of which expressed beta-galactosidase when examined in situ more than 12 months later. These results indicate that stable recombinant gene expression can be achieved in vivo in the mammary gland without altering the growth properties of normal mammary epithelium.

3T3 Cells↗
PubMed1989

Glucocorticoid-enhanced neoplastic transformation of human keratinocytes by human papillomavirus type 16 and an activated ras oncogene.

Human papillomaviruses (HPV) are known etiological agents of benign proliferation of the skin and mucosa (papillomas and warts). They have also been implicated in the development of cervical dysplasia and anogenital carcinoma. The close association of HPV type 16 DNA with the majority of cervical carcinomas suggests the involvement of the virus in this type of cancer. We have developed an in vitro multistep model for human epithelial cell carcinogenesis. Primary human epidermal keratinocytes acquired an indefinite lifespan in response to transfection with HPV 16 DNA but did not undergo malignant conversion. Addition of Kirsten murine sarcoma virus (Ki-MSV), which contains an activated K-ras oncogene, to these cells induced morphological alterations associated with the acquisition of neoplastic properties. The frequency of transformation by Ki-MSV was markedly enhanced by the inclusion of glucocorticoid. At optimal conditions, a 125-fold stimulation was observed. These findings demonstrate the malignant conversion of human primary epithelial cells in culture by the cooperation of HPV type 16 and an activated ras oncogene and support a multistep process for neoplastic conversion. The availability of a human epithelial cell transformation model should facilitate studies of the interaction between HPV and human epithelial cells.

Blotting, Western↗
PubMed1989

Human papillomavirus type 53.

The cloning and partial characterization of the genome of human papillomavirus type 53 is presented. The virus is a distinct type and is most closely related to human papillomavirus type 30.

Cervix Uteri↗
PubMed1987

A new common integration region (int-3) for mouse mammary tumor virus on mouse chromosome 17.

Mus musculus subsp. musculus (Czech II) mammary tumor DNA frequently contains an integrated proviral genome of the mouse mammary tumor virus (MMTV) within a specific 0.5-kilobase-pair region of the cellular genome (designated int-3). Viral integration at this site results in activation of expression of an adjacent cellular gene. We mapped int-3 to mouse chromosome 17 by analysis of PstI-restricted cellular DNAs from mouse-hamster somatic cell hybrids. Restriction analysis of cellular DNA from (C3H/OuJ X Czech II) X Czech II backcross mice established the gene order T-H-2-int-3. These results demonstrated that the int-3 locus is distinct from two other common integration regions for mouse mammary tumor virus (designated int-1 and int-2) in mammary tumor DNA and suggest that several cellular genes may be at risk for virally induced activation during mammary tumor development.

Animals↗
PubMed1987

Mammary tumorigenesis in feral mice: identification of a new int locus in mouse mammary tumor virus (Czech II)-induced mammary tumors.

A population of Mus musculus subsp. musculus (Czech II), recently isolated from the wild, lack endogenous mouse mammary tumor virus (MMTV) proviral genomes. Some of these mice carry an infectious MMTV [designated MMTV (Czech II)] that is transmitted in the milk and is associated with mammary tumor development. This virus is distinct from laboratory strains of MMTV present in inbred mice. An MMTV (Czech II) genome was found within a 0.5-kilobase region of the cellular genome in five of 16 Czech II mammary tumors. MMTV insertion at this site activates expression of a 2.4-kilobase species of RNA from a previously silent cellular gene. This region of the cellular genome was designated int-3 since it is unrelated to the int-1 and int-2 loci. The int-3 locus does not appear to correspond to other proto-oncogenes but is well conserved among mammalian species.

Animals↗
PubMed1987

Genetic mapping of Prm-1, Igl-1, Smst, Mtv-6, Sod-1, and Ets-2 and localization of the Down syndrome region on mouse chromosome 16.

Molecular probes were used as markers in the backcross (Czech II X BALB/cPt) X Czech II to determine the positions of six genes on mouse chromosome 16 (MMU 16). The order of the genes mapped is (centromere), protamine-1 (Prm-1), immunoglobulin lambda 1 light chain (Igl-1), preprosomatostatin (Smst), an endogenous mouse mammary tumor virus locus (Mtv-6), and two more distal sequences, superoxide dismutase, cytoplasmic form (Sod-1), and the proto-oncogene sequence Ets-2. The largest recombination frequency between any two adjacent markers is 24 cM, and thus the position of any marker on MMU 16 that is polymorphic between these two strains can be readily determined in this backcross. A region of MMU 16 which corresponds to the Down syndrome region of human chromosome 21 is located near the distal end of the chromosome.

Animals↗
PubMed1986

An endogenous mouse mammary tumor virus genome common in inbred mouse strains is located on chromosome 6.

We have examined EcoRI-restricted cellular DNA from mouse-hamster somatic cell hybrids. Results of this analysis show that the unit II mouse mammary tumor virus proviral genome is located on mouse chromosome 6. Restriction analysis of cellular DNA from (C3H/OuJ X Czech II) X Czech II backcross mice showed a strong linkage between unit II and Igk. The gene order of these markers on chromosome 6 relative to the Raf and Kirsten murine sarcoma virus ras-2 proto-oncogenes was established.

Animals↗
PubMed1984

Effect of MuLV-related genes on plasmacytomagenesis in BALB/c mice.

The role of spreading somatic cell infections with ecotropic MuLV viruses in the induction of plasmacytomas in BALB/cAN pi mice was determined by constructing congenic mice that lacked the gene locus Cv that codes for ecotropic virus. DBA/2 mice that lack Cv on chromosome (chr) 5 carry a closely linked gene Rmcfr that determines resistance to infection with mink cell focus-forming viruses (MCF). Rmcfr was retrogressively back-crossed onto BALB/c for six successive generations to produce N6 mice. N6 mice were mated to each other to produce BALB/c.DBA/2 Rmvfr/Rmcfr homozygotes. This stock of mice lacked Cv, as demonstrated by DNA hybridization and were as fully susceptible to developing plasmacytomas as the parental BALB/c. A second congenic stock BALB/c.DBA/2 Rmcfr/Rmcfr Fv-1n/Fv-1n was also developed, but the mice of this stock showed a reduced incidence of plasmacytomas, as did BALB/c.DBA/2 Fv-1n/Fv-1n mice. These findings indicated Fv-1 or a gene closely linked to it conferred partial resistance to plasmacytomagenesis. In constructing the BALB/c.DBA/2 Fv-1n/Fv-1n stock, a "control" congenic BALB/c.DBA/2 Fv-1b/Fv-1b was also developed at N6. Surprisingly, this stock carried the Qa2+ trait. These mice were also partially resistant to plasmacytomagenesis, suggesting a gene on chromosome 17 (the location of Qa2) or a gene located elsewhere that regulates Qa2 expression is linked to a gene controlling partial resistance to plasmacytoma development.

Animals↗
PubMed1982

Novel class of mouse mammary tumor virus-related DNA sequences found in all species of Mus, including mice lacking the virus proviral genome.

Mice in breeding colonies of feral Mus musculus brevirostris (Azrou, Morocco), M. m. musculus (Studenec, Czechoslovakia), and M. m. molossinus (Fukuoka, Japan) were found to lack the mouse mammary tumor virus (MMTV-alpha) proviral genome in their germ line. MMTV-alpha proviral genomes have been found in all inbred strains of M. musculus by using high-stringency nucleic acid hybridization conditions. We conclude that feral mice in these colonies are heterozygous for a limited number of MMTV-alpha proviral genomes and that those lacking them arose as a result of random chromosomal segregation. All mice in another breeding colony of feral M. m. musculus (Sladeckovce, Czechoslovakia) lack MMTV proviral genes. By relaxing the conditions of nucleic acid hybridization, MMTV-related sequences (designated MMTV-beta) were detected in restricted cellular DNA from MMTV-negative mice and all other inbred strains and feral species of the genus Mus. The apparent ubiquity of the MMTV-beta DNA sequences in the genus Mus and the lack of variation in the pattern of restriction fragments containing these sequences within a species distinguishes them from MMTV-alpha. These results suggest that the MMTV-beta DNA sequences either are the evolutionary progenitors of the infectious MMTV genome or represent an accumulation of evolutionarily divergent MMTV-alpha insertions into the mouse germ line.

Animals↗
PubMedDate not supplied

False-positive HIV-1 test results in a low-risk screening setting of voluntary blood donation. Retrovirus Epidemiology Donor Study.

CONTEXT: Persons at risk of human immunodeficiency virus 1 (HIV-1) infection, have been classified incorrectly as HIV infected because of Western blot results, but the frequency of false-positive Western blot results is unknown. OBJECTIVES: To determine the frequency of false-positive HIV-1 Western blot results in US blood donors and to make projections to other screened populations. Secondarily, to validate an algorithm for evaluating possible false-positive cases. DESIGN: A retrospective cohort study of HIV-1 enzyme immunoassay (EIA) and Western blot results from large blood donor screening programs in which donors with suspected false-positive Western blot results underwent HIV-1 RNA polymerase chain reaction (PCR) testing and follow-up HIV-1 serology. SETTING: Five US blood centers participating in the Retrovirus Epidemiology Donor Study. PARTICIPANTS: More than 5 million allogeneic and autologous blood donors who successfully donated blood at 1 of the 5 participating centers from 1991 through 1995. MAIN OUTCOME MEASURES: Rate of false positivity by Western blot and true HIV-1 infection status as determined by HIV-1 RNA PCR and by serologic follow-up of blood donors more than 5 weeks after donation. RESULTS: Of 421 donors who were positive for HIV-1 by Western blot, 39 (9.3%) met the criteria of possible false positivity because they lacked reactivity to p31. Of these, 20 (51.3%) were proven by PCR not to be infected with HIV-1. The false-positive prevalence was 4.8% of Western blot-positive donors and 0.0004% (1 in 251000) of all donors (95% confidence interval, 1 in 173000 to 1 in 379000 donors). CONCLUSIONS: A false diagnosis of HIV-1 infection can result from the combination of EIA and Western blot testing in blood donor and other HIV-1 screening programs. Individuals with a positive Western blot result lacking the p31 band should be counseled that, although they may be HIV infected, there is uncertainty about this conclusion. These individuals should be further evaluated by RNA PCR testing (if feasible) and HIV serologic analysis on a follow-up sample.

AIDS Serodiagnosis↗