Virus induction of osteosarcomas in mice

A virus extractcd from an osteosarcoma of a mouse produces simiillar fumors when Injected into newborn mice. The original tumor appeared spoiltaneously in an untreated CFI male. The time between inoculation with virus and detection of bone sarcoma has been as short as 23 days.     

Diabetes mellitus: induction in mice by encephalomyocarditis virus

Hyperglycemia and lesions of the pancreatic islets of Langerhans developed in some, but not all, adult mice infected with a variant of the encephalomyocarditis virus. Large amounts of virus were recovered from the pancreas during acute stages of infection. At this time blood glucose concentrations were markedly elevated and the islets of Langerhans exhibited focal necrosis and degranulation of beta cells. Evidence of abnormal glucose metabolism persisted for varying periods after recovery from the infection. The islets of Langerhans of chronically hyperglycemic mice were distorted and decreased in size, and the beta cells were degranulated. Encephalomyocarditis virus appears to cause diabetes mellitus by reducing the mass of functional beta cells of the islets of Langerhans.     

Lymphomas in mice: failure of induction after a graft-versus-host reaction

A mild graft-versus-host reaction induced in (BALB/cJ x DBA/2J) F(1) mice by the administration of parental spleen cells that differ at several weak histocompatibility loci did not influence the development of lymphomas in these animals. Rous sarcoma virus also failed to induce tumors in the runt and control animals. Breast carcinomas, presumably due to contamination of the inoculums with mammary tumor virus, occurred in those experimental groups given parental cells, whether or not they were viable or immunologically competent. We found no evidence that the immunologic process-as represented by the graft-versus-host reaction-is causally related to the induction of neoplasia.     

Human papovavirus (JC): induction of brain tumors in hamsters

Eighty-three percent of hamsters inoculated at birth with JC virus, a human papovavirus isolated from brain tissue of a case of progressive multifocal leukoencephalopathy, developed malignant gliomas within 6 months. Three brain tumors have been serially transplanted as subcutaneous tumors. JC virus was isolated from five of seven tumors tested. Cells from four tumors were cultivated in vitro. These cells contained an intranuclear antigen with the characteristics of a T antigen, and this antigen was antigenically related to SV40 T antigen. Although virus was not recovered from extracts of serially cultured tumor cells, JC virus was rescued when one tumor cell line was fused with permissive cells.     

Burns and other skin lesions: microcirculatory responses in man during healing

Morphological changes in the cutaneous microcirculation during wound healing have been studied by capillaroscopy in man. In experimental and accidental burns, abrasions, and lacerations, in addition to the anticipated revascularization by the deeper dermal vessels, a distinctive pattern of response by the surrounding papillary capillaries was consistently observed. This appears to be a general phenomenon in healing of skin lesions and suggests the possibility that a potent capillary-attracting factor may be produced within the injured tissue.     

金柑多倍体诱导初探

以秋水仙素为诱变剂,应用混培法和浸渍法诱导金柑(Fortunella crassifoliaSw ingl)多倍体,结果表明:浸渍法的诱导效果优于混培法;种子用0.1%秋水仙素浸渍60 h,多倍体诱变率最高,达22%;变异植株移栽的成活率高于二倍体;变异植株茎粗、矮化,叶片变大、蜡质层厚,叶色浓绿,气孔增大,气孔密度减少,具有较强的抗逆性。     

Delayed hypersensitivity: bone marrow as the source of cells in delayed skin reactions

Adult Lewis rats were thymectomized, irradiated, and restored with bone marrow from allogeneic (or F(1)) donors. They were passively sensitized to tuberculin by a subsequent transfer of Lewis lymph node cells and were given intradermal skin tests with tuberculoprotein. In 24-hour skin reactions the majority of cells, in successive experiments, were shown to be allogeneic (or F(1)) with the use of isoantibody against the antigens of the transplanted marrow cells and by the indirect fluorescent antibody technique. Our results demonstrate that the non-specific cells making up a large proportion of the infiltrating elements in tuberculin skin reactions probably originate in the bone marrow.     

Estrogenic induction of ornithine decarboxylase in vivo and in vitro

Injection of estrogens (17beta-estradiol or diethylstilbestrol) into immature chicks results in a marked (30- to 50-fold) increase in the ornithine decarboxylase activity of oviductal homogenates within a 4-hour period. Similar stimulations were obtained when estrogen was injected into hypophysectomized or castrated rats and the uterus was examined for decarboxylase activity. An elevation of decarboxylase activity was obtained in vitro when oviducts from immature chicks were incubated in the presence of estrogen. These data indicate a direct action of estrogen on oviduct tissue to promote a rapid increase in the activity of a specific enzyme and represent the first example of a completely in vitro enzyme response to estrogen.     

Recombinant interferon enhances monoclonal antibody-targeting of carcinoma lesions in vivo

Heterogeneity in the expression of tumor-associated antigens, as defined by the binding of monoclonal antibodies, is a characteristic common to most, if not all, human carcinoma cell populations. Antigen-negative cells within the population can escape detection and therapy by their failure to bind the appropriate antibody. Therefore, the extent of antigenic heterogeneity is an important consideration when designing protocols for the management of cancer by administration of monoclonal antibodies. One approach to counteracting the effect of antigenic heterogeneity is the use of clone A of recombinant human leukocyte interferon (Hu-IFN-alpha A). Administration of Hu-IFN-alpha A in vivo effectively increased the amount of tumor antigen expressed by a human colon xenograft in situ and augmented the localization of a radiolabeled monoclonal antibody to the tumor site. Concomitant administration of Hu-IFN-alpha A and monoclonal antibody may thus be effective in overcoming the antigenic heterogeneity of carcinoma cell populations and in enhancing the efficacy of monoclonal antibodies in the detection and treatment of carcinoma lesions.     

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.     

Induction of benzo( )pyrene hydroxylase in human skin

Foreskins from children who were circumcised 2 to 4 days after birth contain an enzyme system that hydroxylates the carcinogen benzo[alpha]pyrene. When foreskin was cultured for 16 hours in the presence of 10 micromolar benz[alpha]anthracene, a two- to fivefold increase in activity of benzo[alpha]pyrene hydroxylase was obtained. An evaluation of the basal activity and inducibility of carcinogen-metabolizing enzymes in human tissues may provide a means of determining the ability of different individuals to metabolize carcinogens.     

Effect of stress on skin transplantation immunity in mice

Chronic avoidance-learning stress was found to depress the immune reaction responsible for skin homograft rejection to a modest but significant degree. This effect was observed in a genetically uniform as well as a heterogeneous line of mice.     

鱼类病毒性出血性败血症病毒核蛋白基因的原核表达

通过逆转录聚合酶链式反应(RT-PCR)获得编码病毒性出血性败血症病毒(Viral hemorrhagic septicemia virus,VHSV)核蛋白基因,将其克隆至原核表达载体pET28a,并在E.coli BL21(DE3)中得到表达,用SDS-PAGE与Western-blot对表达产物进行鉴定。结果表明,通过RT-PCR扩增获得长度为1 221bp核蛋白基因片段,诱导表达重组质粒pET28a-N,经SDS-PAGE检测,IPTG终浓度为1mmol/L时,诱导5h蛋白表达量最高,获得的目的蛋白大小与N蛋白的预测分子质量一致,约为48ku。诱导后的菌液进行超声波破碎后,将沉淀和上清分别用于SDS-PAGE电泳,结果表明目的蛋白主要以包涵体的形式存在。表达蛋白经过复性、纯化,得到了较高纯度的可溶性蛋白。经Western-blot检测表明,该表达产物能被羊抗VHSV阳性血清特异性识别。     

Gut reactions of radioactive nitrite after intratracheal administration in mice

Intratracheal administration to mice of radioactive nitrite labeled with nitrogen-13 (13NO2-) (half-life, 9.96 minutes) in dosages that do not cause pharmacological perturbation reveals that oxidative and reductive reactions occur in different organs. Oxidation of 13NO2- to radioactive nitrate (13NO3-) predominates in the blood and liver. Reduction of 13NO2- occurs in those mice that harbor intestinal microflora; this reduction does not occur in germ-free mice. The intestinal reduction products include ammonium, glutamate, glutamine, and urea. With a detection limit of about 0.01 percent of the instilled nitrogen-13, no labeled nitrosamines were detected within 30 minutes. Reduced nitrogen-13 is transported out of the intensive into the circulatory system and appears in the urine along with 13NO3-. The biological half-period for 13NO2- destruction is about 7 minutes, and both oxidation and reduction products are formed.     

不同年龄牦牛皮肤厚度变化研究

【目的】探讨牦牛皮肤随年龄增长的厚度变化规律.【方法】采集初生、半岁及成年牦牛皮肤样品,利用千分尺测量各部位皮肤厚度,采用常规石蜡切片技术,H.E染色和Masson’s三色染色方法,分别测量各部位皮肤表皮层、角质层、表皮非角质层及真皮层厚度,对所得数据进行统计学分析.【结果】牦牛躯体不同部位皮肤厚度存在差异,最厚的部位是颊部、颈腹侧及背部,最薄的部位是腹股沟及腋下.从背部到腹部、外侧面到内侧面皮肤厚度呈递减趋势.【结论】牦牛皮肤厚度随年龄增长呈增厚趋势,其中真皮层增厚趋势最明显,表皮层增厚趋势相对不明显.详细总结了牦牛皮肤厚度在不同躯体部位及不同年龄的变化规律,为更深入地研究牦牛皮肤的生长发育提供依据.     

玉米幼芽提取物对小鼠皮肤UVA照射损伤的保护作用

研究了玉米幼芽提取物(extract of maize plumule,EMP)对长波紫外线(UVA)损伤的小鼠皮肤超微结构、抗氧化酶活性及脂质过氧化作用的影响。结果表明,UVA模型小鼠真皮细胞内出现空泡变性,线粒体肿胀、嵴减少,粗面内质网和核周间隙扩张;表皮细胞微绒毛减少,细胞固缩,细胞核染色质边集。EMP保护的小鼠皮肤细胞损伤程度明显减轻,结构基本正常。EMP可显著提高UVA辐射小鼠皮肤组织中的SOD活性(P<0.01)及CAT活性(P<0.05),降低MDA含量(P<0.05),与VC的抗氧化作用一致。表明EMP能够抵抗UVA对皮肤组织的氧化损伤。     

Artificial induction of androgenetic diploid in Yellow catfish （Pelteobagrus fulvidraco）

Androgenesis was the especial zoogamy that the germ plasma of offspring was from the agnate.In this study the eggs of Yellow catfish(Pelteobagrus fulvidraco)were irradiated by UV suspending in the synthetic ovarian fluid(OF),and the total dosage of UV irradiation was 220 mJ·cm~(-2).Diploid could be induced by heat shock(40℃,2 min,3 min)with different time period after fertilization(15-37 min).The result showed that heat shock with 2 min was better than 3 min;there were two apices of induction in 17-21 min and 27-31 min after fertilization.The highest hatching rate was 3.30% at 29 min after fertilization,and the difference between two apices of induction was unobvious.