Male sterility in the domestic fowl (Gallus domesticus) after 1-(2-chloroethyl)-3-(4-methylcyclohexyl)-1-nitroso-trans-urea (NSC-95441) treatment of chicks.

Of 11 male baby chicks treated twice with 3 mg of 1-(2-chloroethyl)-3-(4-methylcyclohexyl)-1-nitroso-trans-urea (once on the day of hatching and once on the day after), 9 showed absolute lack of spermatogenesis and 2 showed severe inhibition when examined at the age of 6 months. Plasma testosterone level was not altered, however, and histologic examination revealed well-organized testicular interstitial tissue with an abundance of Leydig's cells. In the lining of the seminiferous tubules only Sertoli's cells were present. The weight of the testes from treated animals was only about 10% of control weight. These findings emphasized the possibility that the nitrosoureas cause severe damage to the reproductive system in man.

Morphologic characterization of proliferative cells and virus particles in turkeys with lymphoproliferative disease.

The tumors found in turkeys having lymphoproliferative disease (LPD) are histologically characterized by a pleomorphic population of cells of the lymphoid series. Electron microscopy has shown that, despite marked differences in shape and size, the proliferating cells share basic ultrastructural features, indicating their lymphoid origin. Virus particles morphologically and morphogenetically characteristic of type C oncorna-viruses of Retraviridae were found in different organs and plasma samples of diseased or infected turkeys with LPD. This LPD type C virus resembled members of the reticuloendotheliosis virus group but not members of the avian sarcoma virus group.

Studies on a transplantable murine rhabdomyosarcoma.

Well-differentiated rhabdomyosarcomas developed in 8 of 10 BALB/c mice inoculated with cell-free extracts of two lesions arising in bats previously inoculated with the Moloney strain of murine sarcoma virus. The tumors could be transplanted in BALB/c mice and other strains of mice compatible at the H-2 locus. A tumorigenic clonal cell culture line (R2) was established from a transplanted tumor. Ultrastructural studies of the primary and transplanted tumors and R2 cells revealed thick and thin myofilaments characteristic of myoblasts. These cells contained numerous cisternal type-A virus-like particles, but no type-C particles were found. Attempts to recover, rescue, or chemically induce transforming or nontransforming viruses from transplantable tumors and the R2 cell line were unsuccessful. The tumor cells lacked the murine type-C virus gs antigen. Hybridization data confirmed the apparent lack of viral RNA in the tumor cells.

Some aspects of host response to levamisole after chemotherapy in a murine leukemia.

Levamisole (LMS), when used with an effective remission-inducing drug in leukemic mice, resulted in a high percentage of long-term survivors. Histologic examination of spleens from treated leukemic mice showed that LMS caused an earlier return of lymphoid cells in the splenic lymphoid follicles and lymphoid elements in the red pulp.

Drug therapy against a transplantable guinea pig leukemia.

The effects of six clinically active drugs were tested against a ttansplantable leukemia in inbred strain 2 guinea pigs. Cytoxan and 6-mercaptopurine were found to elicit a therqeutic response against this leukemia based on complete tumor regression of the established tumor as well as a substantial increase in survival time. Animals dying in the untreated control and drug-treated groups revealed typical generalized lymphoblastic leukemia. However, only Cytoxan-treated animals that had relapsed exhibited central nervous system involvement originating from the arachnoid membrane. A tow-drug combination of Cytoxan and 1-(2-chloroethyl)-3(trans-4-methylcyclohexyl)-1-nitrosourea was found not only to prevent meningeal leukemia development but also to result in "curing" all animals from their leukemia. This observation was based on a complete clinical, hematological, and histopathological "remission" period up to 176 days. The administration of 1-(2-chloroethyl)-3-(trans-4-methylcyclohexyl)-1-nitrosourea alone was observed not only to control the systemic leukemia but also to prevent central nervous system involvement. No relapses occurred after the first "remission" period was achieved in the groups of animals that received 1-(2-chloroethyl)-3-(trans-4-methylcyclohexyl)-1-nitrosourea.

Characteristics of ovine and caprine lentivirus infections.

A majority of ovine lentivirus (OvLv) infections seen on farms develop after long incubation and a slow progression of disease to death but in nature they may also have short latency and cause acute leukoencephalitis and/or acute arthritis and pneumonia in young kids or lambs with exceptionally high mortality. Histopathologically, OvLv diseases may be characterized by lymphoid infiltration, lymphoid hyperplasia with germinal centers and plasmocytosis in the lungs and/or in the CNS, joints and udder. Lymphoid hyperplasia in lymph nodes and spleen, as well as lymphoid infiltration in the kidneys, are almost always seen in advanced cases. In some cases, it shows similarities to lymphoproliferative diseases that are considered malignant. Alveolar epithelial hyperplasia in the lungs is generally also seen, especially in older goats with caprine arthritis encephalitis virus (CAEV), and proliferation of these epithelial cells may form acine and papillary structures and in some cases are histopathologically indistinguishable from tumor nodules seen in sheep pulmonary adenomatosis. Because of complexities in the host-lentovirus interaction, cell-associated transmission and extensive antigenic and genomic variation among infecting isolates, control of infection or prevention of spread are problematic by traditional methods and exploration of alternative control strategies employing selection and expansion of animals genetically resistant to OvLv or transgenic for certain viral genes, merits consideration. Interestingly, the pure Awassi sheep breed are susceptible to infection but do not develop the disease, as do European breeds or cross-breeds in Israel, ie they are infected but not diseased. It seems that the local Bedouin black goat breed is resistant to infection of CAEV under natural conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

Propagation and characterization of novel canine lentivirus isolated from a dog.

We have recently isolated a novel canine lentivirus (canine immunodeficiency virus, [CIV]) from a leukemic dog. The virus was isolated from buffy coat cells obtained from the leukemic dog co-cultivated with indicator cells. The virus particles encode a reverse transcriptase with a preference for magnesium, have a density of 1.16 g/ml in sucrose, and induce syncytia in permissive cell lines such as Himalayan tahr ovary and canine fetal thymus. CIV replicates to high titer and highly purified virus can readily be prepared. The ultrastructure and morphogenesis of CIV is strikingly similar to that displayed by other lentiviruses, while immunoblot analysis failed to demonstrate close immunological relatedness to any other lentivirus or oncovirus. These findings suggest that this canine virus, representing the first isolation of a canine retrovirus, belongs to the lentivirus subfamily but is not closely related to other known members.

The oncostatic effect of methyl-CCNU on various experimental lymphoreticular neoplasms.

Studies on the chemotherapeutic potential of methyl-CCNU on experimental leukemias were undertaken. A number of murine transplantable in vivo lines (chemical carcinogen-induced T and B leukemias; radiation- and viral-induced T leukemias of C57BL/6, C3H/eb and SJL/J origin; radiation-induced myeloid leukemias and spontaneous reticulum cell neoplasms of SJL/J mine) were used in these studies. The optimal dose of methyl-CCNU and optimal timing of administration were extensively investigated on two sample lines of T cell leukemias of C57BL/6 mice. Leukemic cell eradication could be achieved in almost all of the different leukemias treated, irrespective of whether induction was brought about by chemical or physical means or due to a viral leukemogenic agent. Studies undertaken to elucidate the effect of methyl-CCNU on the establishment of preleukemic cells following induction of leukemia by the radiation leukemia virus (RadLV) or by total body irradiation, indicated the oncostatic effect of methyl-CCNU on early preleukemic cells.

The effect of high doses of methyl-CCNU on male and female fertility in SJL/J mice.

Single IP injection of high dose (LD 10) of methyl-CCNU administered to sexually mature male mice resulted in severe inhibition of spermatogenesis and reduction in testicular wet weight, without significant changes in plasma testosterone levels, and with hyperplasia of the interstitum, including Leydig cells, in the testis. These effects were temporary, spermatogenesis and testiculer weight recovered 50 days after treatment. Mating of the treated males with normal females demonstrated absolute sterility at 20 days and full recovery at 50 days after treatment. Administration of a single lethal dose (38 mg/kg, LD70) of methyl-CCNU to immature (25 day-old) male mice also caused severe but temporary inhibition of spermatogenesis, and mating of mice which survived the treatment and reached sexual maturity, with normal females, resulted in 80 to 100% pregnancies at 40 and 70 days after treatment, respectively. Three repeated injections of 30 mg/kg (at 10 day intervals) of methyl-CCNU to 15 day-old male mice resulted in inhibition of spermatogenesis without alteration in plasma testosterone. Ninety days after this treatment, only 40% of matings with normal females resulted in pregnancies. Female mice treated once with 20 mg/kg of methyl-CCNU, 3 days before or 7 days after mating with normal males, showed complete failure to complete pregnancy-resorption of the embryos was demonstrated in those female mice treated 7 days after mating. After a second mating trial with these two treated groups, performed 40 to 55 and 42 days after the first trial, respectively, 80 and 86% of the females delivered offspring. However, average litter size was reduced to 4 in the second group, as compared to 8 in untreated mice. There were no apparent birth defects in the offspring of methyl-CCNU treated male or female mice.

Effect of beta-endorphin on steroidogenesis by bovine luteal cells.

To determine if opioid peptides have a local effect on the modulation of progesterone (P4) synthesis, a study was made of the effect of beta-endorphin and leu-enkephalin on P4 production by pure preparations of small luteal cells and dissociated luteal cells comprising both small and large cells from cows 2-3 months pregnant. Corpora lutea were dispersed by collagenase, and the large and small luteal cells were separated using Percoll gradients. Viable luteal cells (5 x 10(5)) were incubated in 0.5 mL of Eagle medium for 2 h at 37 degrees C, in an atmosphere of 5% CO2. Cells were treated with 8-bromoadenosine 3',5'-monophosphate (8Br-cAMP), hCG, beta-endorphin (BE) and leu-enkephalin (LE) alone or in combination. When small luteal cells were used, P4 synthesis was significantly enhanced in the presence of opioid peptides alone (P less than 0.01); there was an additive effect with 8Br-cAMP and with hCG. For dissociated luteal cells, opioid peptides alone had no effect on P4 production but the stimulation of P4 production induced by 8Br-cAMP or hCG was significantly (P less than 0.01) inhibited in the presence of opioid peptides. In contrast, dissociated luteal cells that were preincubated with PGF2 alpha (degranulation) responded to the presence of BE with increased P4 synthesis similar to that seen with the pure preparation of small luteal cells. It is concluded that opioid peptides play an auto/paracrine role in both basal and tropic hormone-induced stimulation of steroidogenesis by the bovine luteal cell.

Effect of lymphoproliferative disease virus and of niridazole on the in vitro blastogenic response of peripheral blood lymphocytes of turkeys.

Turkeys inoculated at 5 weeks of age with lymphoproliferative disease (LPD) virus developed typical lesions in the spleen, thymus, and pancreas. The in vitro blastogenic response of peripheral blood lymphocytes to the mitogens phytohemagglutinin and concanavalin A was drastically (up to 90%) suppressed in the inoculated turkeys 1 to 4 weeks postinoculation compared with uninoculated controls, and even at 11 weeks the response was about 50% inhibited. A lethal (about LD33) dose of antihelminthic drug niridazole, 100 mg/kg given each day for 3 days to 4-week-old turkeys, caused a transient inhibition of the blastogenic response within 32 days of treatment, which was less pronounced than that observed in turkeys inoculated with LPD virus, whether pretreated with niridazole or not. Virus-associated reverse transcriptase activity in the plasma was significantly higher in the turkeys pretreated with niridazole, and LPD lesions developed to the same extent in the untreated and treated groups, as determined 9 weeks post virus inoculation. A sublethal dose of niridazole, 50 mg/kg given each day for 4 days, did not suppress the blastogenic response to mitogens at any time determined (starting 10 days post-treatment) and did not affect the pathogenesis of LPD and the viremia. Body weights were significantly decreased by virus infection and by treatment with lethal doses of niridazole.

Presence of virus particles in neural cells of goats with caprine arthritis encephalitis.

The possible neurotropism of ungulate lentivirus was examined in clinical cases. Brain and ganglion tissue samples were examined from six female goats with caprine arthritis encephalitis and from six healthy controls. Ultrastructural examination revealed typical cytoplasmic A type retrovirus particles in the neural tissue of the diseased does. None were seen in the respective controls. Furthermore, no budding or extracellular retrovirus particles were seen in any of the neural tissue samples examined.

Lack of maedi viral related RNA in pulmonary carcinoma of sheep (jaagsiekte).

Molecular hybridisation with radioactively labelled DNA complementary to the RNA of the maedi virus was used to probe for homologous RNA in the polysome fraction of pulmonary carcinomas (jaagiekte) of Awassi sheep. No sequence homology was detected, which suggests that maedi (or visna) virus is not implicated in the aetiology of pulmonary carcinoma of sheep.

Heterotransplantation of experimentally induced sheep lung adenomatosis into nude mice.

Male ICR nude mice inoculated subcutaneously with minced tissue obtained from pulmonary adenomatosis of sheep which was induced by RNA type-C retrovirus developed a transplant which contained cysts lined by a proliferative epithelium. These cysts showed several characteristics of the epithelial tumour cells of origin, such as high glycogen content and secretion of mucin. Microinvasion of epithelial cells from the adenomatous cysts into the stroma was observed. The stromal tissue demonstrated islets of cartilage. It was concluded that virus-induced pulmonary carcinoma of sheep can be transplanted and grown in nude mice.

Isolation and preliminary characterisation of a novel retrovirus isolated from a leukaemic dog.

A novel canine retrovirus was isolated from mononuclear cells of the peripheral blood of a leukaemic dog. The main clinical and pathological findings in this dog were lethargy, anorexia, weakness, dyspnoea, severe anaemia, thrombocytopenia and a high white blood cell count, practically all of which were lymphoblasts. The virus was isolated from mononuclear cells obtained from the blood, cocultivated with indicator cells. The virus particles encode a reverse transcriptase with Mg++ preference, have a density in sucrose gradients of 1.16 g ml-1, and induce syncytia in permissive cell cultures such as Himalayan tahr ovary and canine fetal thymus lines. This agent replicates to high titres. The virus exhibits a morphogenesis and morphology typical of lentiviruses. Immunoblotting and competitive radioimmunoassays failed to detect immunological crossreactivity with other representative lentiviruses and oncoviruses of the retrovirus family.

Appearance of ovine progressive pneumonia virus outside the United States.

A recently isolated Israeli retrovirus from a sheep with maedi-visna was compared with other retroviruses, using cDNA-RNA hybridization in solution. The Israeli isolate was shown to have close, if not identical, genetic homologic features with the ovine progressive pneumonia virus reported in the United States, rather than with those of the maedivisna viruses of European origin.

Some pathogenic aspects of murine sarcoma virus (Moloney) in rats.

The oncogenic effect of the murine sarcoma virus (Moloney) was tested in rats. Host-age and virus-dose dependent variations in the pathogenic spectrum were found. Four tumour "stages" were described: progressively lethal; lethal after long stationary period; complete tumour regression; tumour reoccurrence after complete regression. Virus recovery was highest from the progressively growing tumours and in the reoccurred neoplasms, while no virus was found in stationary tumours or in those sites where regression had occurred. Tumour onset and death was more rapid and frequent when inoculation of the virus was in muscle-rich tissues. When inoculation was into different visceral organs or intravenously, tumour development still occurred primary in muscle tissue.

The effect of early treatment with methyl-CCNU on the lymphoid organs and the humoral immune response in chickens.

Presented are data upon the effect of a single or muliple administration of methyl-CCNU (a nitrosourea derivative an alkylating agent, and anticancer drug) to newly-hatched chicks. Lethal and sublethal doses of methyl-CCNU caused temporary damage to the lymphoid organs, of which the bursa was apparently the most sensitive. The decreased weight and the morphological changes observed in the bursa of treated chicks were accompanied by a parallel decrease in serum gamma-globulins level. The humoral immune response of animals treated with me-CCNU to sheep red blood cells and to killed Brucella abortus organisms was impaired in about 30% of the treated animals examined 8-10 weeks following 2 injections of 3 mg me-CCNU (given at the day of hatching and the next day). The thymus recovered rather rapidly from treatment. The time schedule of mortality and the early and late toxic manifestations of the drug as observed in chickens, in this study, are similar to previous reports obtained in mammals. Prolonged effects, however, were noted to some extent on body and spleen weight, and most dramatically, on testicular weight, morphology, and function.

Iron, transferrin, and acid and alkaline phosphatase in healthy turkeys and in turkeys inoculated with the lymphoproliferative disease virus.

Presented are data on iron-binding capacity determinations in the serum of turkeys infected with lymphoproliferative disease (LPD) virus and in healthy males and females (laying eggs and nonlaying) from a breeding flock. Also presented are results of serum and tissue total acid and alkaline phosphatase determinations in turkey poults infected with LPD virus and their uninfected controls and of serum enzyme levels in healthy males and females from the breeding flock. There was no significant alteration in total iron binding capacity (transferrin level) in the serum of turkeys with LPD. Turkey poults inoculated with LPD virus showed a significant decrease in serum alkaline phosphatase activity 4 and 7 weeks postinfection (pi), and a decrease in serum acid phosphatase activity 7 weeks pi. Acid and alkaline phosphatase activity determined in the spleen and pancreas (organs with pronounced tumor involvement) 7 weeks pi did not differ significantly from that of healthy controls, although there was a tendency for both enzymes to decline in the pancreas of the infected turkeys. Healthy laying female turkeys demonstrated marked elevation in serum transferrin level and in acid and alkaline phosphatase activity, as compared with males of the same age. Serum alkaline phosphatase of turkey poults was markedly higher than that of adult turkeys.