THE EFFECT OF METHYL CCNU (NSC-95441) ON THE CELLULAR KINETICS OF NORMAL AND LEUKEMIC MURINE TISSUES IN VIVO

The effect of MeCCNU on the cellular kinetics of normal and leukemic murine tissues is examined in vivo . A prolongation in the S phase is noted after doses of MeCCNU as low as 4 mg/kg, and this prolongation persists for approximately 4 hr after the dose. No persistent alteration in the growth fraction is produced by MeCCNU. The generation time of the cells regrowing after MeCCNU is slightly prolonged, compared to normal L1210 leukemia. Simultaneous studies on ascites tumor, normal bone marrow, and normal gastrointestinal mucosa, using the in vivo uptake of ³H-thymidine into DNA, have shown a differential effect on the tumor and normal tissues.     

THE EFFECT OF ULTRA-VIOLET,X-RAY,AND RADIUM RADIATION ON THE TOXICITY OF NORMAL BLOOD

While the number of experiments performed is perhaps somewhat limited the results obtained were quite definite and warrant the following conclusions. The toxicity of normal blood for living plant protoplasm as studied on the growth of Lupinus albus seedlings is definitely influenced by various radiations. Ultra-violet rays produce no effect on normal blood or may even render it slightly less toxic. Roentgen rays render normal blood more toxic. The toxicity is greater in the case of the blood plasma as compared with the blood cells and a more toxic effect is produced with the Coolidge tube as compared with the gas tube. Radium emanations in the few experiments performed produced changes very much the same as those given by the x-rays.     

前列腺组织中神经生长因子(NGF)表达的研究

研究前列腺组织中神经生长因子（ＮＧＦ） 的生理学意义。采用原位杂交和免疫组化法, 检测４３ 例前列腺增生组织, ８ 例腺癌组织和８ 例正常组织中β－ＮＧＦｍ ＲＮＡ及其蛋白的表达及分布。结果显示β－ＮＧＦｍ ＲＮＡ 在正常组织及增生组织中定位于间质细胞, 偶见于上皮细胞中; 而在癌组织中, 上皮细胞和间质细胞有同样强度的β－ＮＧＦｍ ＲＮＡ染色。其蛋白在良性组织中表达主要着色在间质细胞中,上皮细胞呈弱表达,而癌组织中上皮细胞见着色明显增强（Ｐ＜ ０．０５）。ＮＧＦ的自分泌异常可见是前列腺组织由良性向恶性转变的原因之一。     

THE 'TRANSITION PROBABILITY MODEL' AND THE REGULATION OF PROLIFERATION OF HUMAN DIPLOID CELL CULTURES DURING AGING

Genealogies derived from time-lapse cinemicrophotographic studies of aging human diploid cell cultures were analysed in terms of the ‘transition probability’ model. It was found that the distribution of intermitotic times obtained from middle passage cells deviated only slightly from that predicted by the model. In contrast, the plot for late passage cultures did not fit the predicted pattern and appeared to be composed of multiple curves. These changes are discussed in reference to cellular senescence as expressed by normal human diploid cells in vitro.     

无Ca^2＋外淋巴灌流对短时噪声听损伤的作用

已有报道Ｃａ２＋在噪声所致耳蜗病理损伤中起重要作用。本实验比较采用不含Ｃａ２＋人工外淋巴鼓阶灌流和对照灌流耳蜗在接受到１１５ｄＢＳＰＬ白噪声暴露１ｈ后耳蜗各种生物电反应的差异,以探索降低外淋巴Ｃａ２＋浓度是否能减轻噪声所致的听觉损伤。结果提示,用无Ｃａ２＋外淋巴降低鼓阶Ｃａ２＋浓度可部分压抑耳蜗声电响应,但强噪声所致的耳蜗功能损伤将减轻。本文在多种电生理指标的综合分析中对此种低Ｃａ２＋保护的机制做了初步探讨。     

THE INFLUENCE OF BROOD SIZE ON THE ENERGY METABOLISM AND WATER LOSS OF NESTLING GREAT TITS PARUS MAJOR MAJOR

At normal outdoor temperatures there is a distinct influence of brood size on the heat production of ten-day-old Great Tits. One ten-day-old nestling proved unable to maintain its body temperature at 12^°C. Two ten-day-old tits together in one nestbox at 12^Á°C were able to elevate the air temperature sufficiently to maintain homoiothermia. The same of course holds for tits in larger broods.
At an air temperature of 18^°C, six or seven ten-day-old tits placed in a nestbox elevated the air temperature to a level at which they almost reached a state of hyperthermia: their metabolism was at the basal level. The basal metabolism of a ten-day-old tit was found to be slightly more than 0–1800 kcal/h. The metabolism intensity of 12 tits in a nestbox at 12^°C was of the same order of magnitude.
Tits in broods comprising more than 12 or 13 nestlings at normal outdoor temperatures probably develop hyperthermia, which is unfavourable both for their energy and for their water balance.     

MOBILIZATION OF HAEMOPOIETIC STEM CELLS (CFU) INTO THE PERIPHERAL BLOOD OF THE MOUSE; EFFECTS OF ENDOTOXIN AND OTHER COMPOUNDS

Factors affecting the circulation of haemopoietic stem cells (CFU) in the peripheral blood of mice were investigated. I.v. injection of sublethal doses of endotoxin, trypsin and proteinase appeared to raise the number of CFU per ml blood from about 30–40 to about 300–400 or more within 10 min. The effect was smaller when smaller doses of the substances were injected. After this initial rise the number of circulating cells returned to normal in a few hours. Following endotoxin there was a second rise which started 2–3 days after injection and attained a peak on the 6th–7th day. The first rise is explained as a mobilization of stem cells from their normal microenvironments into the blood stream; the second rise is considered to reflect proliferation of CFUs in the haemopoietic tissues. The spleen seems to be acting as an organ capturing CFUs from the blood and not as a source adding stem cells to the blood.
The early mobilization of CFU after endotoxin injection did not coincide with a mobilization of neutrophils. The number of circulating band cells was increased during the first hours.
The importance of 'open sites'in the haemopoietic tissue for capturing CFUs was studied by emptying these sites through a lethal X-irradiation and injecting normal bone marrow cells. When a greater number of syngeneic bone marrow cells was injected intravenously, the level of circulating CFU in irradiated mice was slightly lower than the level in unirradiated mice during the first hours.     

SOME COMPARISONS OF THE KINETIC PROPERTIES OF FEMORAL AND SPLENIC HAEMOPOIETIC STEM CELLS

A slightly different radiosensitivity is confirmed between colony forming units (CFU) in the femur as opposed to those of the spleen. The recovery pattern of the CFU in the femur and in the spleen following sublethal doses of radiation can be markedly different, depending on the radiation dose, particularly concerning the postirradiation ‘dip’. The turnover state of splenic CFU appears to be greater in normal animals than that of the femoral CFU. Hypertransfusion doubles the splenic CFU by the fourth day, while only marginally affecting femoral CFU. Erythropoietin, while increasing the CFU turnover significantly in both femur and spleen of the polycythaemic animal, also increases femoral but not splenic CFU.     

THE PHYSICAL AND CHEMICAL ENVIRONMENT OF THE DEVELOPING EMBRYO OF PINUS RESINOSA

The relationship between changes in soluble protein, hexose sugar, total lipid concentration, and osmotic potential occurring in gametophytic supernatant of Pinus resinosa Ait. during in vivo embryogenesis was measured. The effects of varying sucrose levels of culture medium on in vitro embryo and gametophyte development were examined. Increases in embryo volume, and fresh and dry weight of the female gametophyte during in vivo embryogenesis coincide with increasing levels of soluble protein, hexose sugar, and total lipid in the gametophytic supernatant. In contrast, osmotic potential of the supernatant increased only slightly between the zygote and proembryo stages of embryo development, and remained constant thereafter. Gametophytes plus embryos grown in vitro achieved dry weights approaching those of in ovulo gametophytes on media containing levels of sucrose up to 21%. Gametophytes on media with sucrose concentrations up to 21% also resembled normal in ovulo gametophytes in appearance. However, embryo development appeared to be suspended on treatment media containing from 9% to 21% sucrose, while embryos degenerated on media with constant sucrose levels of 3% and 6%. A treatment medium containing approximately 12% sucrose would provide an osmotic environment that duplicates that found in ovulo. While greater sucrose levels promoted more normal gametophyte development in Pinus resinosa, we failed to achieve complete development of the embryo in vitro. Conclusions and implications drawn from these results are discussed.     

THE EFFECT OF TEMPERATURE ON THE DEVELOPMENT OF THE POTATO-ROOT EELWORM, HETERODERA ROSTOCHIENSIS

Experiments on the effect of temperature on the development of Heterodera rostochiensis are described. Temperatures above 20° C. slightly reduce penetration of larvae into the potato root and greatly restrict their development in the plant tissues. The temperature range of this parasite is compared with that of H. marioni , and a possible relationship to their geographical distribution is discussed.