Wild mouse retrovirus-induced neurogenic paralysis in laboratory mice. I. Virus replication and expression in central nervous system.

Ecotropic wild mouse retrovirus (1504 M)-induced neurogenic paralytic disease has been studied in inbred strains of mice. The major criterion for the successful transmission of the disease in the laboratory strains of mice is inoculation of high titer ecotropic virus in FV-1n strains of mice at newborn stage (less than or equal to 1 day old), Hybridization studies using 1504 M viral cDNA as probe indicate that in nonparalyzed mice, the inoculated virus replicates primarily in spleen tissue, whereas virus replication is evident in both spleen and central nervous system (CNS) tissue of paralyzed mice. Our studies on virus gene expression indicate that both viral gag gene product p30 and env gene product gp70 are expressed in brain, spinal cord and spleen tissues of paralyzed mice.

Mink type C virus: biochemical characterization of the structural polypeptides.

Mink type C virions contained six major protein species of approximate M.W. of 90,000, 70,000, 30,000, 15,000, 12,000 and 10,000.

Survival and mutation of Chinese hamster cells after ultraviolet irradiation and caffeine treatment.

UV-irradiated Chinese hamster cells on post-irradiation treatment with caffeine in growth medium for 24 h gave rise to biphasic UV-survival curves. At caffeine concentrations between 0.001 and 0.

Effect of carcinogen release rate on the incidence of preneoplastic and neoplastic lesions of the respiratory tract epithelium in rats.

Inbred F34 rat tracheal transplants were exposed to 7,12-dimethylbenz[a]anthracene (DMBA) delivered at different release rates for intraluminal pellets made of various matrices to study the effect of carcinogen dose rate on the induction of lesions in the epithelium. These matrices were beeswax, beeswax-stearyl alcohol, and beeswax-cholesterol. In addition, DMBA absorbed onto carbon particles was dispersed in beeswax-stearyl alcohol.

O6-methylguanine-DNA methyltransferase in wild-type and ada mutants of Escherichia coli.

O(6)-Methylguanine-DNA methyltransferase is induced in Escherichia coli during growth in low levels of N-methyl-N'-nitro-N-nitrosoguanidine. We have developed a sensitive assay for quantitating low levels of this activity with a synthetic DNA substrate containing 3H-labeled O(6)-methylguanine as the only modified base. Although both wild-type and adaptation-deficient (ada) mutants of E.

Binding characteristics of wild mouse type C virus to mouse spinal cord and spleen cells.

Binding characteristics of mouse spinal cord and spleen cells to naturally occurring, ecotropic (paralytogenic and lymphomagenic 1504M virus) and amphotropic (lymphomagenic 1504A virus) retroviruses of wild mice were investigated. 125I-labeled ecotropic (N-tropic) virus bound efficiently to both spinal cord and spleen cells from SWR/J mice (Fv-1n), but labeled amphotropic (N-tropic) virus bound efficiently only to spleen cells. The extent of binding of 1504M virus to the spinal cord cells was related to the time of incubation and to the amount of labeled input virus.

Tetracycline-induced mutation in cultured Chinese hamster cells.

After tetracycline hydrochloride (TC) treatment for 48 h, we obtained 8-azaguanine-resistant mutants in a population of cultured Chinese hamster cells. Optimal expression of mutation was reached after about 5 days, and mutation frequency remained constant thereafter. There was a gradual increase in the yield of mutants with increasing doses of TC, and measurable yield was observed at a dose as low as 10 microgram of TC per ml.

Characterization of a highly oncogenic murine leukemia virus from wild mice.

We have isolated a highly lymphomagenic wild mouse virus by passage of a weakly oncogenic amphotropic murine leukaemia virus (MuLV-A) in NIH Swiss mice. This virus is similar in host range, interference and neutralization properties to that of the inoculated amphotropic virus but is distinct from it biochemically and causes lymphomas in 90-100% of mice within 1-2 months. Our results indicate that this highly oncogenic virus is a recombinant of wild mouse MuLV-A and sequences related to env gene region of the endogenous xenotropic virus of NIH Swiss mice.

The induction of specific-locus mutations and sister-chromatid exchanges by 5-bromo- and 5-chloro-deoxyuridine.

The induction of 6-thioguanine-resistant (TGr) mutants and sister-chromatid exchanges (SCE) by 5-bromo- and 5-chloro-deoxyuridine (BrdU and CldU) was determined with Chinese hamster ovary cells in culture. Over a concentration range of 0.5-200 microM, CldU treatment caused 3-5 times the number of SCEs found with BrdU; for example, with 10 microM CldU, 60.

Characterization of genome structure of amphotropic and ecotropic wild mouse retroviruses.

We studied the RNA genomes of several wild mouse type C retroviruses by using RNase T1-oligonucleotide fingerprinting. The amphotropic and ecotropic viruses of field strain 1504 produced very similar oligonucleotide fingerprints, but each also had several unique oligonucleotides. All of these unique oligonucleotides were located in the env gene region and were probably responsible for the host range differences between these viruses, as well as the lymphomagenic and paralytogenic properties of the viruses.

Immunopathology of natural and experimental lymphomas induced by wild mouse leukemia virus.

Naturally occurring lymphomas of Lake Casitas (LC) wild mice, and the lymphomas induced by LC murine leukemia virus (MuLV) in Swiss mice from the National Institutes of Health, displayed remarkably similar gross, microscopic, and functional characteristics. They spared the thymus, arose primarily in the splenic red pulp, became leukemic, and were comprised of stem cells lacking classic T- and B-cell markers. Cytoplasmic and surface immunoglobulin were undetectable in 34 of 35 spontaneous LC lymphomas and in any of ten LC MuLV-induced lymphomas in NIH Swiss mice.

Natural killer cell activity in a population of leukemia-prone wild mice (Mus musculus).

Natural cell-mediated cytotoxicity against YAC-I targets was measured in splenocytes from leukemia-prone wild mice trapped near Lake Casitas (LC) in southern California. Cytotoxicity was mediated by cells that were non-adherent to nylon wool, non-phagocytic and resistant to thy-1.2 antiserum plus complement.

Liquid-liquid extraction of osmium thiocyanate with hexamethylphosphoramide and direct spectrophotometric determination in the organic phase.

The use of hexamethylphosphoramide (HMPA) in the osmium-thiocyanate system makes the method more sensitive and selective. The blue colour formed by osmium(VIII) with thiocyanate in 1.5M hydrochloric acid is intensified in the presence of HMPA and the complex becomes readily extractable into chloroform.

A rapid and selective method for direct gravimetric determination of vanadium(V) and its application to alloy steel and some rocks.

N-o-Iodobenzoyl-o-tolyhydroxylamine has been synthesized and used as gravimetric reagent for direct determination of vanadium(V). The complex dried at 105-120 degrees has the definite composition VO(C(14)H(11)O(2)NI)(2)Cl. The method is simple, rapid, sensitive and selective and gives results reproducible within 0.

Akvr-1, a dominant murine leukemia virus restriction gene, is polymorphic in leukemia-prone wild mice.

We describe a restriction gene (Akvr-1, for AKR virus restriction) that is polymorphic for two alleles, Akvr-1R (restrictive) and Akvr-1r (susceptible), in a feral population of mice (Mus) musculus domesticus) at a squab farm near Lake Casitas (LC) in southern California. Akvr-1k is a dominant allele that exhibits 100% penetrance in prevention of viremia of AKR endogenous retrovirus and of virus-mediated lymphoma in LC (Akvr-1RR) X AKR F1 hybrids. The restriction phenotype segregates as a single Mendelian locus in backcrosses to AKR mice.

Pathologic changes induced in respiratory tract mucosa by polycyclic hydrocarbons of differing carcinogenic activity.

Seven aromatic polycyclic hydrocarbons (PCHs) were investigated for their toxic effects on respiratory mucosa: benzo(e)pyrene (BeP), pyrene, anthracene, benz(a)anthracene(BaA), dibenz(a,c)anthracene(DBacA), benzo (a)pyrene (BaP), and dimethylbenz(a)anthracene (DMBA). The compounds were chosen because they comprise a spectrum of PCHs ranging from noncarcinogens, to initiators, to weak and strong carcinogens. All of them except DMBA are environmentally relevant chemicals.

Selective gravimetric method for direct determination of tin(IV) with N-o-toluoyl-N-o-tolylhydroxylamine and its application to brass and bronze analyses.

A selective gravimetric method for determination of tin(IV) with N-o-toluoyl-N-o-tolylhydroxylamine by direct weighing as Sn(C(15)H(14)NO(2))(2)Cl(2) is recommended. The metal complex, dried at 110-120 degrees , gives reproducible results. The method is simple, rapid and quantitative over a wide range of acidity (1-4N sulphuric acid) and is superior to existing gravimetric methods.