Dopamine protects mice against whole-body irradiation

Injection of dopamine before whole-body x-irradiation of mice resulted in 80 percent survivors whereas no irradiated controls survived; injection after exposure had no effect. D,L-Dihydroxyphenylalanine, the precursor of dopamine, had no effect on survival when injected either before or after irradiation.     

Perfluorochemical emulsions can increase tumor radiosensitivity

An oxygen-carrying perfluorochemical emulsion enhanced the effectiveness of radiation therapy in two transplantable solid tumors in mice. The perfluorochemical emulsion had no effect on tumor growth after x-irradiation, but delayed tumor growth significantly when administered to oxygen-breathing mice before or during irradiation.     

兔骨髓间充质干细胞的分离培养

为探讨体外分离及培养扩增兔骨髓间充质干细胞(MSCs)的方法,无菌采取兔股骨,用含20%FBS的DMEM培养液冲骨髓腔,采用全骨髓细胞贴壁培养法对MSCs进行纯化扩增,倒置显微镜下观察原代及传代细胞的形态、生长情况、绘制细胞生长曲线。结果显示,MSCs为贴壁生长细胞,形态均匀呈纤维样,增殖能力强,多次传代仍能保持其生物学特性。采用全骨髓贴壁培养法能够较好地纯化和扩增MSCs。     

Lymphoepithelial tissues of the intestine and differentiation of antibody production

The antibody response of young rabbits to the injection of killed Brucella abortus was abolished by prior extirpation of intestinal lymphoepithelial tissues combined with lethal xirradiation and reconstitution with rabbit fetal liver cells. Extirpative surgery alone, like lethal x-irradiation and reconstitution without surgery, did not abolish this response. Intestinal lymphoepithelial tissues of rabbits apparently play a central lymphoid function and are responsible for the differentiation of the lymphoid cell line which produces specific antibody and immunoglobulins.     

白藜芦醇对骨髓损伤的修复作用

目的探讨白藜芦醇对辐射导致小鼠骨髓损伤的修复作用。方法 80只小鼠随机分为正常组、模型组、实验组和对照组,每组20只。除正常组外,其余各组以辐射造成小鼠骨髓型急性损伤模型;实验组和对照组分别腹腔注射白藜芦醇100mg/kg和甲基强的松龙100mg/kg,正常组和模型组则腹腔注射等量生理盐水,连续治疗7d,检测小鼠外周血白细胞、骨髓单个核细胞以及骨髓CD34＋细胞数。结果给药后实验组的白细胞计数、骨髓单个核细胞数和CD34＋细胞百分率与给药前比较差异均有统计学意义（P〈0.05）,且均高于同一时间点的模型组（P〈0.05）。实验组各时间点的白细胞数、骨髓单个核细胞数和CD34＋细胞百分率与对照组比较差异均无统计学意义（P〉0.05）。结论白藜芦醇可增加放射损伤小鼠白细胞、骨髓单个核细胞和CD34＋细胞的数目,加快骨髓造血功能的恢复。     

Radioprotection by mitotic inhibitors and mercaptoethylamine

In the mouse, chemical interference with cellular proliferation alters the radiosensitivity of the bone marrow, and this results in protection from otherwise lethal x-irradiation. When intestinal damage is minimized by appropriate timing and dosage, many mitotic inhibitors increase radioresistance and enhance the protective effects of mercaptoethylamine.     

Low-level irradiation and threshold shift in the visual receptor

Customary methods of stimulating and recording were used to examine threshold shifts of the single visual receptor in the lateral eye of Limulus in response to low-level x-irradiation. Marked visual sensitization was found and was most pronounced at the lowest dosage levels (1 to 25 r). Complete light adaptation apparently cancelled the effects of the irradiation.     

日龄对仔猪股骨骨髓组织抗菌肽PR-39 mRNA表达的影响

为探明日龄对仔猪非特异性免疫形成的影响,分别于仔猪出生当天,3,14,23,28 d,随机屠宰杜长大仔公猪4头,采集股骨骨髓组织.用一优化的RT-PCR方法,以18S rRNA作内标,半定量分析不同日龄仔猪骨髓组织抗菌肽PR-39 mRNA表达的差异.结果表明:不同日龄间仔猪骨髓组织PR-39 mRNA相对表达量存在明显的差异.出生时最低,吮吸初乳2 d后显著增加,14日龄时较3日龄显著下降,随后随日龄的增加,其表达量呈上升趋势.     

Bone marrow transplantation

The goals in bone marrow transplantation are its application to the treatment of diseases arising in the blood-forming tissues of man. Techniques for procuring and grafting marrow are of the needle-and-syringe type and are based on the normal physiological processes in which stem cells circulate through blood and other fluids of the mammalian organism. Destruction of bone marrow by irradiation, chemicals, or unknown agencies provides the immediate experimental system for demonstrating the therapeutic value of marrow transplants. Genetic diseases characterized by abnormal marrow function are also modifiable by grafts of blood-forming tissues. Studies with identical twins are critical experiments for showing the clinical value of grafts, even though the transplanted cells cannot be identified by the usual marker techniques. Among the best results seen with marrow grafting is the presumed cure of certain rare hereditary immune-deficiency disorders of children. A major problem in bone marrow transplantation-one that delays its wider clinical application-is the immune reaction from cells growing out of the foreign transplant which attack the host (the graft-versus-host reaction). Attempts to use a graft-versus-host response to eliminate tumor cells is a part of the marrow research program. The history of the processes that led to some of the achieved goals in marrow grafting shows the usual multicentric origin of an idea. Certain individuals play critical roles in developing the idea. Finally, a body of knowledge is accumulated that opens up or limits prospects for the future. In bone marrow transplantati on, future achievements will depend in part on the progress that is made in the areas of cell separation, bone marrow banking, and tissue culture.     

New light-sensitive cofactor required for oxidation of succinate by Mycobacterium phlei

Irradiation of the electron transport particles of Mycobacterium phlei with light at a wavelength of 360 manometers resulted in a loss of oxidase activities of succinate and the reduced form of nicotinamide adenine dinucleotide. The lesion in the two pathways caused by irradiation of the particles differs. The succinoxidase pathway was more labile to irradiation than the pathway linked to nicotinamide adenine dinucleotide. Restoration of succinoxidase activity (up to 50 to 60 percent) occurred on addition of a thermostable, water-soluble material obtained from Mycobacterium phlei cells or with an extract of mitochondria from boiled rat liver. Other known cofactors, such as flavine adenine dinucleotide, flavine mononucleotide, benzo- and naphthoquinones, as well as sulfhydryl agents, failed to restore succinoxidase activity after irradiation. Water-soluble material from Mycobacterium phlei appears to function between the flavoprotein and cytochrome b on the succinoxidase pathway. In contrast to the requirements for restoration of the pathway linked to nicotinamide adenine dinucleotide, restoration of succinoxidase does not occur with quinones or other cofactors such as flavine adenine dinucleotide.     

X-ray resistant cell required for the induction of in vitro antibody formation

Mouse spleen cells were separated into two populations on the basis of adherence to plastic. The recombination of these two populations was required for the in vitro antibody response to sheep erythrocytes. By separating the two populations from x-irradiated mice and combining each with the other population prepared from normal mice, it was demonstrated that the immunologic function of the nonadherent population only was highly sensitive to x-ray injury. In contrast, x-irradiation in doses as high as 1000 roentgens had no measurable effect on the immune function of adherent cells, that is, the population which first interacts with antigen and is composed principally of large phagocytic cells.     

Corneal calcification

Superficial calcification was produced in the normal rabbit cornea by mild irradiation with a carbon dioxide laser. The calcification was entirely extracellular and closely resemnbled that observed in human band keratopathy, which was characterized as hydroxyapatite by x-ray diffraction. The electron-mnicroscopic appearance of calcific spheriules and conglomerates in early cornteal calcification is presented. The calcific spherules arise at the basal plasma membrane surface of the epithelial cells in close relation to their basement membrane.     

Leukemogenesis by urethan in C57B1 mice bearing isologous tissues from x-irradiated mice

A single exposure of mice of a low-leukemic strain (C57B1/6) to 400 r of total-body x-irradiation caused the early appearance of a factor which, though not itself capable of inducing leukemia in adult C57B1 recipients, did cause its appearance when the recipients also received urethan by injection. Positive results were obtained with seven different tissues from irradiated animals, whether urethan was injected 1 day or 30 days after the irradiation. No such effect was obtained in either series in the absence of urethan treatment. When urethan was injected into normal C57B1 mice, or into mice previously implanted with tissues from nonirradiated mice, only marginal leukemogenic activity was evinced. The possible involvement of a precursor virus is discussed.     

无居民海岛开发利用存在的问题及开发模式探讨——以浙江舟山为例

结合浙江舟山市无居民海岛开发利用现状,分析了当前无居民海岛开发利用存在的问题,并探讨了无居民海岛的重点开发、适合开发、保护开发和禁止开发4种开发模式,提出了无居民海岛可持续发展的保障条件,为今后舟山市无居民海岛的开发利用提供了参考模式。     

SOD对紫外辐射受损的苏云金芽孢杆菌作用的研究

探讨了超氧化物歧化酶 (SOD)等自由基清除剂对苏云金芽孢杆菌紫外辐射的影响。结果表明 ,SOD、绞股蓝皂甙等自由基清除剂能够明显地提高紫外辐射损伤细胞的存活率 ,并且SOD的保护作用表现为防护与恢复两种不同的作用。又通过细胞电泳与琼脂糖凝胶电泳发现紫外辐射后其细胞膜及质粒DNA均受到了明显的损伤 ;SOD对细胞膜损伤有一定的恢复作用 ,而对DNA不表现恢复效应。由此认为 :紫外线对细胞膜及DNA均有损伤 ,SOD恢复作用的主要部位在细胞膜而不是DNA分子。为进一步确定SOD的作用以及利用自由基清除剂制备高效的Bt农药提供了理论基础。     

Low-level x-ray damage to amphibian erythrocytes

In vitro x-irradiation of frog and Amphiuma erythrocytes caused cytophysiological damage to part of the cell population. There was a significant decrease in the percentage of normal cells and some hemolysis. Changes were also observed in the electrical capacitance and potassium-42 uptake of irradiated erythrocytes.     

Transplantation of marrow to extramedullary sites

Autologous fragments of transplanted marrow have survived in various extramedullary sites in the rat, rabbit, and dog. Survival of the fragments occurs with a complete reconstitution of the hemopoietic and adventitial structures. The process originates from a network of surviving reticular cells which proliferate and differentiate into osteoblasts and give rise to trabecular bone. Later, the reticular cells reconstruct the marrow's microcirculation. Hemopoietic repopulation of the marrow implant takes place only after its sinusoidal microcirculation has been established.     

Serum concentration: effects on cycle and x-ray sensitivity of mammalian cells

If the content of serum in the culture medium of exponentially growing Chinese hamster cells is below optimum (15 percent), the doubling time and the resistance to x-irradiation of the cells are increased. In synchronously dividing populations the increase in doubling time is primarily caused by increase in duration of the postmitotic (G(1)) phase of the cells; this phase is relatively radiation resistant. The response of the cells growing synchronously is related quantitatively to the response of the cells dividing randomly.     

苜蓿皂苷对X射线照射小鼠造血系统的影响

为研究苜蓿皂苷(Alfalfa saponin)对X射线照射小鼠造血系统的影响,选取雄性SPF级昆明系小鼠90只,随机分为对照组和试验组,研究25、50和100mg/ml的苜蓿皂苷对X射线照射强度为4.0Gy小鼠造血系统的影响和不同剂量X射线对添加25mg/ml的小鼠造血系统的影响。结果表明:1)预防性给予25mg/mL苜蓿皂苷,可显著减轻4.0Gy的X射线对小鼠外周血白细胞(White blood cells,WBC)、红细胞(Red blood cells,RBC)和血小板(Platelets,PLT)数量的降低程度(P0.05),增加照射小鼠的骨髓有核细胞(Bone marrow nucleated cells,BMC)数(P0.05),显著降低微核率(P0.05)。2)预防性给予25mg/mL的苜蓿皂苷,相同照射剂量的试验组小鼠白细胞、红细胞、血小板和骨髓有核细胞数显著高于对照组(P0.05),微核率显著低于对照组(P0.05)。3)随照射强度增加,25mg/ml的苜蓿皂苷保护小鼠受辐射损伤的能力下降。综上,苜蓿皂苷可缓解X射线对小鼠造血系统和染色体的损伤,苜蓿皂苷浓度与射线强度存在量效关系,需要根据不同的照射强度添加不同浓度的苜蓿皂苷。     

Xenon: effect on radiation sensitivity of HeLa cells

HeLa cells, plated onto plastic petri dishes, were exposed to various atmospheres composed of air and carbon dioxide; helium, oxygen, and carbon dioxide; and xenon, oxygen, and carbon dioxide in a pressure vessel. Survival curves with x-rays, 280 kilovolts (peak), show that air and helium have the same effect, but that xenon potentiates x-irradiation to the extent that the dose to produce a given level of survival with xenon is 0.58 of the dose required with air.