Rapid viral induction of plasmacytomas in pristane-primed BALB-c mice

Strain BALB/c mice were injected intraperitoneally with 0.5 milliliter of pristane, and 39 to 56 days later they were infected with Abelson murine leukemia virus, which is a lymphosarcomagenic variant of Moloney virus. Fifty-eight percent of the mice developed lymphosarcoma, and 28 percent developed immunoglobulin-producing plasmacytomas within 20 to 93 days (77 to 149 days after the pristane injection). Two of 57 control mice developed plasmacytomas at days 138 and 166 after a single injection of pristane; no plasmacytomas were found in mice treated with virus alone.     

Resistance of wild Norway rats in North Carolina to warfarin rodenticide

Reports concerning the ineffectiveness of warfarin rodenticide, used at farms and stores in a rural area about 8 kilometers in diameter near Raleigh, North Carolina, prompted subsequent laboratory testing. All of the 25 Norway rats trapped from the area survived 6 days of no-choice feeding of bait containing 0.025 percent (by weight) warfarin.     

Vaccinia dermal infection and methylcholanthrene in cortisone-treated mice

Cortisone-treated mice were inoculated with vaccinia virus, and then five paintings of methylcholanthrene were applied over the site of inoculation. In 70 percent of the mice, tumors developed at the site of inoculation, and 35 percent of the mice, with and without skin tumors, also developed lymphomas. Identically treated control mice that were vacciniaimmune developed a significantly lower incidence (38 percent) of both skin tumors and lymphomas     

中华鼢鼠危害调查及防治技术试验分析

通过在退耕还林(草)地工程区设置鼠害防治试验示范小区,对中华鼢鼠运用灭鼠雷、人工地箭及鼢鼠灵防治试验,试验结果鼠药的最佳投放时间应为每年的4～5月份为好,灭鼠雷及人工地箭都堪称为杀灭中华鼢鼠的较佳方法。     

Suppression of HIV infection in AZT-treated SCID-hu mice

The SCID-hu mouse, engrafted with human hematolymphoid organs, is permissive for infection with the human immunodeficiency virus (HIV). This mouse model was used to test compounds for antiviral efficacy. Two weeks after infection with HIV, 100 percent (40/40) of SCID-hu mice were positive for HIV by the polymerase chain reaction. When first treated with 3'-azido-3'-deoxythymidine (AZT), none (0/17) were HIV-positive by this assay. However, AZT-treated SCID-hu mice did have a few infected cells; after AZT treatment was stopped, viral spread was detected by polymerase chain reaction in such mice. Thus, the SCID-hu mouse provides a means to directly compare new antiviral compounds with AZT and to further improve antiviral efficacy.     

Arginine vasotocin: effects on development of reproductive organs

Immature 25-day-old mice were injected daily with 1 microgram of arginine vasotocin for 3 or 4 days and killed 24 hours after the last injection. The ovaries were 30 percent smaller in treated females than in controls. The ventral prostates and accessory organs (seminal vesicles and coagulating glands) were less than half the size of these structures in control males. Similar results were observed when 15-day-old mice were given similar injections and killed 2 weeks after the last injection; furthermore, testis weights were 28 percent smaller than those of controls. It is speculated that arginine vasotocin, which has been found in mammalian pineal glands, might mediate effects of the pineal gland on normal sexual development.     

Antitumor activity in mice of tentacles of 2 tropical sea annelids

Crude extracts of tentacles of two polychaetous annelids completely inhibit growth of Erlich ascites tumor in 60 to 100 percent of treated mice. Dialyzed extracts of one of these annelids, Lanice conchilega, show activity in the retentate after pronase digestion, suggesting that antitumor activity is associated with a nonprotein component of the crude tentacle extract.     

Reduced incidence of persistent chromosome aberrations in mice irradiated at low dose rates

A marked difference was observed between the effectiveness of high and low dose rates of ionizing radiation in producing persistent chromosome aberrations in the marrow cells of mice. Clones of cells with chromosome abnormalities were present in the marrow of all the mice previously exposed to single or fractionated doses of x-rays given at a rate of 30 rad/min. The frequency of chromosome aberrations in these mice varied from 14 to 72 percent of the cells exdmined. By contrast, none of the mice exposed to continuous gamma radiation at a low dose rate (1.45 rad/hour) showed definite clones of abnormal marrow cells, and the frequency of persistent chromosome aberrations varied from zero to 8 percent in this group.     

Leukemogenic activity of filtrates from radiation-induced lymphoid tumors of mice

Cell-free filtrates of x-ray-induced lymphoid tumors of strain C57BL/ Ka mice have elicited, on injection into newborn isologous hosts, a lymphoma incidence of 15 to 19 percent. In control mice of the same subline, the incidence of spontaneous lymphoma is about 1 percent. No leukemogenic activity could be detected in filtrates from thymi harvested at 2 to 32 days following completion of x-ray treatment. Activity was evident at 64 days and was perhaps somewhat greater at 128 days. Serial cell-free passage of filtrates in newborn F(1) hybrid mice resulted in a marked increase in lymphoma incidence (69 percent), coupled with a shortening of the median latency. Supplementary x-irradiation failed to enhance the activity of filtrates after neonatal injection.     

Hemopoietic colony-forming units in regenerating mouse liver: suppression by anticoagulants

After hepatic injury induced by carbon tetrachloride, mitotically active hematopoietic cells of nonhepatic origin localize in the liver as judged by an increase in colony-forming nodules in the spleens of lethally irradiated recipient mice on intravenous injection of cells from these livers. The administration of warfarin suppresses the localization of colony-forming units in the regenerating liver by inhibiting the coagulation mechanism of the donor animals.     

Drug-induced tolerance for skin allografts across the H-2 barrier in adult mice

Mice treated with methylhydrazine derivatives for 3 to 4 weeks before the transplantation showed markedly prolonged survival times for allogeneic skin grafts differing at the H-2 histocompatibility locus. Presumably permanent tolerance was induced in about 20 to 30 percent of the mice when the drug treatment was combined with a single injection of additional donor antigen. The tolerance persists without further drug treatment and is specific for donor tissue.     

Rapid immunological induction of murine lymphomas: evidence for a viral etiology

A graft-versus-host reaction induced in (SJL/J x C57BL/1)F(1) hybrid mice by injection of SJL/J spleen cells resulted in 100 percent incidence of tumors at 40 days. Transplantation studies revealed that the tumors were antigenically C57BL/1. Since both SJL/J and C57BL/1 mice carry tumorigenic virus, the evidence suggests a viral etiology.     

桑黄口服液对小鼠免疫功能的影响

本试验探讨了由桑黄液体发酵液提取桑黄多糖制成的口服液对小鼠免疫功能的影响.结果表明,与对照组相比,桑黄口服液高剂量组(40 mL.kg-1)能显著增加小鼠的胸腺和脾脏的重量,中剂量组(20 mL.kg-1)、高剂量组能显著提高小鼠碳粒廓清率的吞噬指数,腹腔巨噬细胞的吞噬百分率由对照组的13.7%分别提高到22.2%和34.7%,差异达极显著水平.可见桑黄口服液具有提高网状内皮系统功能的作用,可显著增强免疫功能.     

Carcinogen-induced immune depression: absence in mice resistant to chemical oncogenesis

Administration of 3-methylcholanthrene 6 days before antigenic challenge depressed the immune response to sheep red cells in young adult mice (C3Hf/Bi strain) sensitive to the oncogenic effect of the drug (100 percent local tumors 240 days after carcinogen). The drug was not immunodepressant in the I strain, which is relatively resistant to its carcinogenic effect (11 percent local tumors 240 days after carcinogen).     

Hydrocephalus in mice inoculated neonatally by the oronasal route with reovirus type 1

Mice inoculated neonatally by the oronasal route with reovirus type 1 or 2 developed typical acute disease. Fifteen percent of the mice recovered from the acute infection. No further disease was noted in mice infected with reovirus 2, but 9 percent of the survivors of reovirus I infections developed hydrocephalus at a mean time of 109 days after inoculation. Infectious virus could not be isolated from hydrocephalic mice.     

Production of urinary bladder carcinomas in mice by sodium saccharin

Pellets weighing 20 to 24 milligrams and containing 20 percent sodium saccharin suspended in cholesterol were surgically implanted into the urinary bladder lumens of female Swiss mice (60 to 90 days old) under ether anesthesia. Incidences of mouse bladder carcinomas in animals exposed to these pellets were 47 and 52 percent as compared with incidences of 13 and 12 percent in control mice exposed to pellets of pure cholesterol. The exposure of the mouse bladder to saccharin was very brief, because the time required for 50 percent of the compound to be eluted from the pellets was about 5.5 hours.     

Genetic variation of cholesterol ester content in mouse adrenals

Total cholesterol concentrations in muscle, liver, and plasma do not differ significantly between adult male C57BL/10J and DBA/2J mice. In the adrenal glands of these two strains, of their hybrids, and of AC mice, concentrations of free cholesterol vary by 5 percent. Adrenals from C57 mice, however, contain six times as much esterified cholesterol as adrenals from AC or DBA mice. The intermediate concentrations of cholesterol esters in F(1) hybrids suggest that the difference in this measure is inherited additively. The finding of variation in adrenal cholesterol within a species is useful for the further study of the role of cholesterol in steroidogenesis by means of genetic analysis.     

马齿苋多糖对糖尿病小鼠糖脂代谢相关因子的影响

【目的】探讨马齿苋多糖（Polysaccharide of Portulaca oleracea L.,POP）对糖尿病小鼠糖、脂代谢相关因子的影响,为POP的开发利用提供依据。【方法】采用饲喂高糖高脂日粮并注射链脲佐菌素（STZ）的方法,诱导Ⅱ型糖尿病（NIDDM）小鼠动物模型,然后将其分为正常对照组、模型对照组、POP低剂量灌胃组(POP用量100 mg/kg)、POP高剂量灌胃组(POP用量200 mg/kg)和罗格列酮灌胃组(罗格列酮用量3 mg/kg),连续灌胃28 d后,将小鼠断头处死,采集肾组织,检测蛋白激酶B（PKB）、PKC、过氧化物酶体增殖物激活受体γ（PPARγ）等糖脂代谢相关因子在糖尿病小鼠肾脏中表达量的变化。【结果】与模型对照组相比,其余各组小鼠肾组织PKB蛋白、PPARγ蛋白表达量均显著增加(P<0.05),正常对照组、POP高剂量灌胃组和罗格列酮灌胃组小鼠肾组织PKC蛋白表达量显著降低(P<0.05)。【结论】POP能上调NIDDM小鼠PKB、PPARγ基因的表达,能下调PKC基因的表达,从而发挥降低血糖的作用。     

Tumor suppression with a combination of alpha-difluoromethyl ornithine and interferon

alpha-Difluoromethyl ornithine and mouse type 1 interferon, when administered simultaneously, were highly toxic to B16 melanoma cells in culture. Oral administration of alpha-difluoromethyl ornithine suppressed B16 melanoma development in mice 85 percent whereas interferon given subcutaneously inhibited tumor growth only 24 percent. Total or near total suppression of tumor growth was observed in mice receiving both treatments.     

Exencephalia: its occurrence in untreated mice

Exencephalia has been reported in irradiated CFI mice but there are no reports of its occurrence in untreated mice of this strain. In the course of establishing disease-free breeding colonies from CFI female mice delivered of their offspring by cesarean section, exencephalia was seen frequently. During a 2-week period, 90 litters were delivered; 11 contained exencephalic fetuses, at the rate of one per litter (11 of 90 litters, 12.2 percent; 11 of 1056 fetuses, 1.04 percent). The prevalence of this anomaly in untreated mice of this strain could contribute to overestimates of the effectiveness of low doses of radiation.