Biomedical subjects

R D Cardiff

Publications and source records attributed to R D Cardiff.

At least 109 records · Page 6Linked to original sources

PubMed1983

Effects of X irradiation on the growth of normal and hyperplastic mouse mammary gland transplants.

To avoid the problems associated with whole-body radiation, pieces of X-irradiated normal or hyperplastic mammary tissue were transplanted to the host gland-free fat pad of nonexposed mice. The percentage of the fat pad filled by growth of the transplants at 4, 8, and 12 weeks after transplantation was measured. Growth of lobule transplants was moderately inhibited by 4 Gy. While some of the lobules survived 12 Gy, their growth was severely inhibited. The hyperplastic outgrowth lines were variable but more resistant than lobules to growth retardation. Line Z5D was more susceptible than D1, and Z5C1 was least susceptible, with 88% growing well after 12 Gy. In order to distinguish between transient and permanent growth retardation, tissue was taken from the irradiated and control transplants and retransplanted to new hosts without further radiation. The second generation of X-ray-exposed tissue filled more of the fat pad than the first-generation transplants, but significantly less than the nonexposed controls. The experiments described provide a means of demonstrating X-ray-induced changes in the mammary gland from growth inhibition to carcinogenesis.

Animals↗

PubMed1983

Alterations of acquired mouse mammary tumor virus DNA during mammary tumorigenesis in BALB/cfC3H mice.

The patterns of the milk-transmitted (exogenous) mouse mammary tumor virus (MuMTV) DNA restriction endonuclease fragments in the nodule and tumor stages of BALB/cfC3H mouse mammary neoplasia were compared with the use of the Southern blot analysis. Acquired MuMTV restriction fragments were detected in DNA from hyperplastic alveolar nodules (HAN), from primary hyperplastic outgrowths (HPO), from families of transplanted HPO, from tumors from HPO, and from serially transplanted tumors. The restriction fragment patterns suggested that the HAN were composed of clonal dominant populations. Transplantation of subdivisions of individual HAN resulted in HPO with DNA restriction patterns suggesting that HAN also contained two or more subpopulations. In all cases, HAN subpopulations shared MuMTV restriction fragments suggesting a common origin. Forty-seven tumors arising from HPO shared MuMTV restriction fragments with the HPO. Most but not all tumors had additional acquired MuMTV restriction fragments not detected in the progenitor HPO, indicating that they were composed of a distinct subpopulation that originated from the HPO. The restriction fragment pattern in some tumor lines was remarkably stable through many transplant generations. Some tumors had no major additional restriction fragments, suggesting that major rearrangements of MuMTV DNA are not required for tumorigenesis.

Animals↗

PubMed1982

Methylation and amplification of mouse mammary tumor virus DNA in normal, premalignant, and malignant cells of GR/A mice.

The methylation and amplification of mouse mammary tumor virus (MuMTV) proviral DNA was investigated in normal, premalignant, and malignant tissues of GR/A mice. The proviral methylation pattern was examined with the restriction enzyme HhaI, which fails to cleave methylated DNA. MuMTV proviral DNA from liver, kidney, and heart was highly methylated. Proviral DNA was somewhat undermethylated in mammary gland cells from virgin and lactating mice and extensively undermethylated in cells from premalignant outgrowths, pregnancy-dependent tumors, and pregnancy-independent tumors. The restriction enzyme SacI was used to detect additional proviruses in the same cells. No additional proviral copies of MuMTV were detected in liver, kidney, or heart cells or in mammary gland cells from virgin mice. Some mammary gland cells from lactating mice appeared to contain additional copies of the endogenous, highly oncogenic GT-MTV-2 provirus. Premalignant outgrowth, pregnancy-dependent tumor, and pregnancy-independent tumor cells contained an average of two to three additional copies per cell of the GT-MTV-2 provirus. Thus, neoplasia in GR/A mice was directly associated with quantized increases in MuMTV proviral DNA undermethylation and GR-MTV-2 proviral DNA amplification. Restriction enzyme analysis suggested that premalignant outgrowths and pregnancy-dependent tumors both consisted largely of heterogenous cell populations, although some evidence of clonal dominance was detected.

Animals↗

PubMed1982

Identification of a unique mouse mammary tumor virus in the BALB/cNIV mouse strain.

We examined the genetic structure, in terms of restriction endonuclease recognition sites, of the milk-transmitted, low-oncogenic mouse mammary tumor virus (MuMTV) of the BALB/cNIV mouse strain. An analysis with EcoRI documented the presence of acquired cNIV proviruses in the mammary tumor DNAs of BALB/cNIV animals. A comparison of tumor DNAs digested with PstI showed that both the cNIV MuMTV and C3Hf MuMTV proviruses lacked the 4.3- and 1.1-kilobase pair fragments characteristic of C3H MuMTV patterns. An examination of mammary tumor and normal, nonmammary tissue DNAs with BamHI supported the idea that the cNIV MuMTV is identical to the C3Hf MuMTV and demonstrated that these two low-oncogenic proviruses are identical to the high-oncogenic C3H MuMTV provirus with respect to a pair of BamHI sites which define a 1.3-kilobase pair fragment. For each of the three MuMTV strains, we also mapped DNAs generated in isolated virions by reverse transcription of their genomic RNAs. Our results showed that cNIV and C3Hf MuMTV are distinct entities by virtue of an additional PstI site within the cNIV long terminal repeat sequence. Another unique feature of cNIV MuMTV revealed by the analysis of virion-generated DNAs was the existence of a family of genomes within the cNIV population. We concluded that cNIV is distinct from its presumptive C3Hf MuMTV predecessor.

Animals↗

PubMed1982

Detection of acquired provirus sequences in mammary tumors from low-expressor, low-risk mice.

Murine mammary tumor virus (MuMTV) provirus sequences in the DNA from early-occurring (average age 10 mo) and late occurring (age greater than 20 mo) tumors in BALB/cfC3H mice were analyzed by Eco RI restriction endonuclease mapping procedures. All early tumors were MuMTV antigen-positive mammary adenocarcinomas that contained the 0.92- and 4.0-kilo base (kb) exogenous C3H MuMTV-specific Pst I restriction endonuclease fragments. All but 1 of the late mammary adenocarcinomas had MuMTV antigens detected by peroxidase antiperoxidase staining, and all contained the 0.92- and 4.0-kb exogenous virus Pst I fragments. Three late nonmammary tumors lacked both MuMTV antigens and acquired provirus sequences. Greater numbers of MuMTV sequences were detected in both early and late-arising mammary tumors by Eco RI restriction endonuclease mapping than were detected in tissues from uninfected BALB/c mice. However, neither the number nor the location of MuMTV proviruses correlated with tumor latent period.

Adenocarcinoma↗

PubMed1982

A high-tumor-incidence subline of the D1 mouse mammary hyperplastic outgrowth line: effect of carcinogens.

Mammary tumorigenesis in some mouse strains is characterized by the appearance of a preneoplastic lesion, the hyperplastic alveolar nodule (HAN). The biology of the HAN has been characterized primarily through the study of stable outgrowth lines of serially transplanted HAN. One outgrowth line, Dl, which was developed and carried in female BALB/c mice, has been described as a low-tumor-incidence line that does not express murine mammary tumor virus (MuMTV) and is susceptible to hormonal, chemical, and viral carcinogens. In this report, a high-tumor-incidence subline of Dl, Dl/UCD, is described. Although Dl/UCD, like Dl, is susceptible to the chemical carcinogen 7,12-dimethylbenz[a]anthracene, an increase in tumor incidence was not observed when Dl/UCD outgrowth was exposed to hormones by means of pituitary isografts. Unlike Dl, Dl/UCD is refractory to the carcinogenic action of MuMTV. Both Dl and the Dl/UCD subline contained the endogenous MuMTV provirus but did not contain exogenous MuMTV provirus sequences. MuMTV antigen was not detected in Dl/UCD outgrowths or tumors. RNA hybridizable to MuMTV complementary DNA was detected in some Dl/UCD outgrowths and tumors but did not appear to correlate with tumorigenesis.

9,10-Dimethyl-1,2-benzanthracene↗

PubMed1982

Survival of mouse mammary gland transplants of normal, hyperplastic, and tumor tissues exposed to X-rays.

Mouse mammary tissues, including ducts, prelactating lobules, hyperplastic outgrowth lines, and tumors, were exposed to varying doses of X-rays and then transplanted to fat pads of nonirradiated BALB/c mice for study. Estimates of the dose of radiation that would allow survival of 50% of the transplants (SD50) were made with the use of probit analysis. Nearly all duct and lobule transplants survived doses of X-rays from 0 to 800 rad. The survival rate declined rapidly following doses above 800 rad, and the calculated SD50 was 1,020 and 1,260 rad for mammary ducts and lobules, respectively. The three hyperplastic outgrowth lines tested gave very different results. Hyperplastic line Z5C1 transplants had better than 90% survival at doses up to 1,200 rad and an SD50 between 1,200 and 1,600 rad. Hyperplastic line Z5D transplants had an SD50 of between 800 and 1,200 rad. Hyperplastic line D1 transplants had a better than 90% survival following doses of 0-600 rad and an SD50 between 600 and 800 rad. The survival of tumor transplants was 100% following doses of X-rays up to 1,200 rad; the SD50 was in excess of 1,600 rad. The mouse mammary transplantation system can be used to study the direct effect of X-rays on normal, premalignant, and malignant mammary tissues and provides a basis for the study of the radiobiology of mammary tissues.

Animals↗

PubMed1981

Immunological characterization of a low oncogenic mouse mammary tumor virus BALB/cNIV mice.

Antigenic determinants of mouse mammary tumor virus (MuMTV) from the low-mammary-tumor-incidence strain BALB/cNIV were compared by competition radioimmunoassay with those of MuMTV's isolated from several high- and low-mammary-tumor-incidence mouse strains, using rabbit hyperimmune sera against BALB/cNIV MuMTV and against MuMTV from the high-mammary-tumor-incidence strain BALB/cfC3H. Using anti-BALB/cfC3H serum in competition radioimmunoassay, BALB/cNIV MuMTV lacked antigenic determinants present on MuMTV's from the BALB/cfC3H, C3H, and GR strains. With anti-BALB/cNIV serum in competition radioimmunoassay, type-specific antigenicity was detected with BALB/cNIV MuMTV. We found class-specific antigenicities on BALB/cNIV MuMTV that were shared with RIII and C3Hf MuMTV's BALB/cNIV MuMTV was reportedly derived from the C3Hf strain by infection of BALB/c mouse mammary tissue after transplantation into a (BALB/c X C3Hf)F1 hybrid followed by retransplantation into the BALB/c strain (D. R. Pitelka, K. B. DeOme, and H. A. Bern. Proc. Am Assoc. Cancer Res. 6:51, 1965). However, BALB/cNIV MuMTV contained type-specific antigens not present on C3Hf MuMTV. The possible origin of these determinants is discussed.

Animals↗

PubMed1981

Restriction endonuclease studies of hyperplastic outgrowth lines from BALB/cfC3H mouse hyperplastic mammary nodules.

The DNA's isolated from five mouse hyperplastic mammary gland outgrowth lines from BALB/cfC3H mice were digested with the restriction endonucleases PsTI, BamHI, or EcoRI; electrophoresed; and analyzed by Southern blotting and autoradiography. Proviral DNA sequences from the acquired C3H mouse mammary tumor virus were detected in the DNA of all five lines, indicating that they were infected. The DNA of the five hyperplastic lines contained more EcoRI and BamHI mouse mammary tumor virus proviral DNA fragments than did DNA from normal organs, suggesting that the hyperplastic tissues were composed of more homogeneous cell populations than was lactating mammary gland. Each hyperplastic line had unique and reproducible BamHI and EcoRI restriction (integration) patterns which were stable over as many as seven transplant generations. Three sublines, which originated from the same hyperplastic alveolar nodule, had unique integration patterns but also shared several fragments. On the basis of these observations, we propose that mouse mammary "hyperplasias" are clonal dominant premalignant neoplasms.

Animals↗

PubMed1981

Murine mammary tumor virus seroepidemiology in BALB/cfC3H mice: correlation with tumor development.

Serum reactivity to murine mammary tumor virus (MuMTV) was inversely related to mammary tumor risk in 8-to 22-week-old BALB/cfC3H breeding females. Mice at low tumor risk exhibited high-titered serum reactivity to MuMTV (50% end point, greater than or equal to 1:40 by radioimmunoassay) approximately 3-6 months earlier than did the mice at high tumor risk. Maternal MuMTV antibody levels were correlated with the serum anti-MuMTV reactivity of their neonatal offspring (2 wk of age). Serologic antiviral reactivity in infected mice did not change during periods of pregnancy and lactation. All infected animals had detectable serum MuMTV reactivity by 33 weeks of age. The virus-neutralizing capabilities of some of these sera were tested, Sera from some of the young, low-tumor-risk animals that had MuMTV-precipitating antibodies also had virus-neutralizing activity. Conversely, none of the sera from the high-tumor-risk animals had detectable MuMTV-neutralizing antibodies.

Age Factors↗

PubMed1980

Identification and partial characterization of an endogenous form of mouse mammary tumor virus that is transcribed into the virion-associated RNA genome.

Restriction mapping demonstrated the presence of several distinct proviral forms of mouse mammary tumor virus in the genome of GR mice. One of these proviruses (GR-MTV-2) was highly amplified in GR 3A cells, a cell line derived from a GR mammary tumor. By the criterion of restriction mapping, the amplified GR-MTV-2 provirus found in GR 3A cells was identical to the provirus found in M1.19 cells, a rat cell line infected with virions obtained from GR 3A culture fluid. This result clearly implies that the GR-MTV-2 provirus in GR 3A cells was transcribed into the virion-associated viral RNA genome. Cleavage of either GR 3A or M1.19 cell DNAs with the restriction enzyme Bg1 II gave rise to a 2.6 x 10(6) dalton GR-MTV-2 proviral fragment (ca. 45% of the viral genome). This fragment was isolated and mapped with thirteen restriction enzymes.

Animals↗

PubMed1980

Selective amplification of mouse mammary tumor virus in mammary tumors of GR mice.

DNAs extracted from the mammary tumors of GR mice were analyzed for mouse mammary tumor virus proviral sequences by the restriction enzyme-Southern blot procedure. The tumor DNAs contain more proviral copies of mouse mammary tumor virus than DNA from a nonmalignant tissue. The degree of proviral amplification is small (ca. one to five additional copies) and appears to be variable from tumor to tumor. The restriction patterns of the amplified proviral sequences suggest a clonal origin for the tumor mass. In addition, the restriction patterns observed after digestion with the enzymes BglII and SacI indicate that only one of the proviruses endogenous to GR mice is amplified. The amplified provirus found in GR mammary tumors is identical to the provirus that is missing in GR-Mtv-2- mice, a congenic line exhibiting a low mammary tumor incidence.

Animals↗

PubMed1980

Prevalence and distribution of murine mammary tumor virus antigen detectable by immunocytochemistry in spontaneous breast tumors of wild mice.

Mouse mammary tumor virus (MuMTV) antigens were detected by immunoperoxidase cytochemistry in spontaneous breast tumors of wild mice from two widely separated areas of southern California. Eleven of 25 (44%) tumors from Lake Casitas (LC) mice and 4 of 5 tumors from Bouquet Canyon mice were positive. Included among the tumors lacking detectable MuMTV antigen were well-differentiated type A and type B carcinomas as well as tumors with an atypical pattern. In the antigen-positive tumors the distribution of staining was patchy and extremely variable in extent (less than 1-70% stained cells). The intensity and extent of staining were generally greater in breast tumors from hybrids of LC wild mice and C5LBL/10Sn or AKR inbred mice. A good correlation was found in the same tumors between immunoperoxidase staining, detection of MuMTV gp52 antigen by radioimmunoassay, and detection of type B particles by electron microscopy. All of the breast tumors in LC mice were positive for type C virus particles.

Adenocarcinoma↗

PubMed1980

Correlation between the detection of specific mouse mammary tumor proviral sequences and the presence of pulmonary metastases in mice bearing spontaneous mammary tumors.

Pulmonary metastases in C3H/He mice bearing spontaneous mammary tumors were detected and characterized by histological criteria and immunocytochemical staining for mouse mammary tumor virus antigens. The same lungs containing metastases were also positive when assayed for a specific subset of mouse mammary tumor virus proviral DNA sequences. These sequences, termed tumor-associated sequences, have previously been shown to be present in the DNA of spontaneous mammary tumors that arise before 1 yr of age in C3H/He mice but are absent in DNA's of apparently normal tissues of C3H/He mice. Reconstruction experiments demonstrated that the nucleic acid hybridization method will detect at least one mammary tumor cell/250 cells. While DNA from 13 lungs of apparently normal C3H/He mice did not contain sequences homologous to mouse mammary tumor virus tumor-associated-sequence RNA, DNA from lungs of 9 of 12 C3H/He mice bearing spontaneous mammary tumors did contain these sequences. Since the entire DNA content of the lung can be assayed as one sample, the hybridization method minimizes false negatives resulting from histological analysis of random biopsy sampling. The hybridization procedure described here thus represents a sensitive and quantitative element as an adjunct for the detection of micrometastatic lesions in mice bearing viral-mediated spontaneous mammary carcinomas.

Animals↗

PubMed1980

Reevaluation of the effect of mouse mammary tumor virus infection on the BALB/c mouse hyperplastic outgrowth.

The BALB/c (C-) mouse hyperplastic outgrowth line (D1) was used to study murine mammary tumor virus (MuMTV) expression in both D1 and tumors derived from D1. D1 was transplanted into virus-infected BALB/cfC3H (C+) and virus-uninfected C- animals. In duplicate studies, tumor incidence was the same in both groups. However, the tumor latency period was longer for D1 transplanted into C+ mice (D1/C+) than for D1 transplanted into C- mice (D1/C-). MuMTV was detected in 85% of D1/C+ outgrowths and in 29% of D1/C+ tumors but was never detected in D1/C- outgrowths or tumors. D1/C- outgrowth and tumors and most of the D1/C+ tissues expressed little or no MuMTV RNA. Some D1/C+ tumors expressed substantial levels of MuMTV RNA. These same tumors also had MuMTV antigen and contained the exogenously acquired C3H-MuMTV provirus in the cellular DNA as shown by DNA fragment patterns following cleavage with Pst I and Eco RI endonucleases. D1/C+ tumors containing no viral RNA were also antigen-negative and lacked the acquired C3H provirus. These studies indicate that D1 has substantially changed in its incidence and in its response to MuMTV. MuMTV infection was not tumorigenic in the traditional sense, a finding that has led to a reevaluation of our current models of virus-host relationships and the biology of precancerous conditions.

Animals↗

PubMed1980

Development and characterization of mouse hyperplastic mammary outgrowth lines from BALB/cfC3H hyperplastic alveolar nodules.

Five hyperplastic outgrowth lines were developed by serial transplantation of hyperplastic alveolar nodules from BALB/cfC3H mice into BALB/c hosts. The lines were used to study the biology, morphology, and virology of premalignant tissue originating in mouse mammary tumor virus (MuMTV)-positive animals. The five lines differed with respect to tumor potential and growth characteristics, corroborating the previous evidence that MuMTV-positive hyperplastic alveolar nodules are biologically heterogeneous. Subgross and microscopic examination of outgrowths and tumors revealed that each line had unique morphological characteristics. The presence of atypical lobules within the hyperplastic outgrowth appeared to be correlated with tumor risk, and a morphological continuum of atypical lesions ending in overt cancer was suggested. Viral expression was detected by nucleic acid hybridization and immunoperoxidase staining for MuMTV structural antigens. While the MuMTV RNA in certain tissues appeared to vary qualitatively with tumor potential of the outgrowth line, no correlation between viral antigens detected by immunoperoxidase staining and tumor potential was observed.

Animals↗

PubMed1979

In vitro infectivity assay for mouse mammary tumor virus.

Studies of mouse mammary tumor virus (MMTV) have been impeded by the lack of an in vitro infectivity assay. We have developed a rapid, quantitative in vitro assay for MMTV infectivity based on the detection of positively staining foci by immunoperoxidase. This assay and a 50% end-point titration of MMTV infectivity gave identical virus titers. Infection of a rat hepatoma cell line, a feline kidney cell line, and a normal murine mammary gland cell line by virus from the mouse mammary tumor GR3A cell line was linear with respect to virus concentration. The infectious titers obtained in both homologous and heterologous cell lines were not significantly different, demonstrating a lack of host range specificity. Virus infectivity was inactivated by heating at 55 degrees C and by ultraviolet irradiation. Rabbit anti-MMTV serum neutralized the infectivity with a 50% neutralization end point of 1:5000. Applications of this assay to the study of the immunological, biological, and biochemical characteristics of MMTV are discussed.

Animals↗

PubMed1979

Immunocytochemical distribution of mouse mammary tumor virus antigens in BALB/cfC3H mammary epithelium.

The distribution of mouse mammary tumor virus (MuMTV) antigens was studied in normal, preneoplastic, and neoplastic mammary epithelia from female BALB/cfC3H mice with the use of a polyvalent anti-MuMTV serum and indirect immunoperoxidase techniques. The MuMTV antigens were on the apical surface or in focal cytoplasmic aggregates or diffused throughout the infected cells. As much as 70% of all cells in adenocarcinomas and as much as 100% of all cells in preneoplastic hyperplastic alveolar nodules contained MMTV antigens. Comparable percentages of cells from mammary glands of multiparous mice were MuMTV-positive. Some mammary tissues of nullparous and primiparous mice did not contain detectable MuMTV antigen. The MuMTV antigen-containing cells in lactating mammary glands tended to be in discrete lobuloalveolar clusters surrounded by antigen-negative alveoli. The percentage of MuMTV-positive cells in a given gland was proportional to the amount of virus found in the animal's milk.

Animals↗