Mammary cancer induction by 7,12-dimethylbenz(a)anthracene: relation to age

Mammary glands were transplanted from donors treated with 7,12-dimethylbenz(a)anthracene to untreated isologous recipients. Incidence of mammary tumors in mammary grafts from 56-day-old donors was significantly higher than that in grafts from 120-day-old donors, regardless of the age of the recipient hosts. Whent mammary glands were transplanted from untreated donors to isologous recipients that subsequently received 7,12-dimethyl-benz(a)anthracene, a similar difference in tumor incidence in the grafts was observed. In contrast to mammary glands of older females, mammary glands of young adult female rats are highly vulnerable to the carcinogenic effect of 7,12-dimethylbenz(a)anthracene.     

Increased sensitivity of lymphocytes from people over 65 to cell cycle arrest and chromosomal damage

Flow cytometry revealed that, in the presence of tritiated thymidine, a greater percentage of phytohemagglutinin-stimulated lymphocytes from old human donors were arrested in the G2 or M phase than were cells from young donors. Furthermore, lymphocytes from old donors showed significantly more chromosomal damage than did lymphocytes from young donors. Lymphocyte cultures from old or young donors not exposed to tritiated thymidine had the same percentage of cycling lymphocytes in G2 or M, although the number of lymphocytes stimulated by phytohemagglutinin to enter the cell cycle was significantly lower in cultures from old donors. Thus, the impaired incorporation of tritiated thymidine by phytohemagglutinin-exposed lymphocytes from old humans reflects both an impaired proliferative response to phytohemagglutinin and an increased sensitivity to the radiobiological effects of tritiated thymidine.     

Control of experimental diabetes mellitus in rats by transplantation of fetal pancreases

Experimental diabetes mellitus in young adult Lewis rats was successfully treated by transplantation of fetal pancreases from syngeneic fetuses. Complete or partial control lasting up to 165 days was achieved in 64 percent of recipients by using two to three pancreases of fetal age (15 to 18(1/2) days) placed under each kidney capsule. Islets of Langerhans without exocrine elements were present in the transplants.     

特克赛尔肉羊胚胎移植效果

2003～2005年,共同期发情处理特克赛尔供体母羊60只,发情58只,同期发情率达96.67%;同期发情处理受体母羊337只,发情325只,同期发情率达96.44%。2003年超排处理特克赛尔供体母羊14只,查黄体142个,采用输卵管冲胚技术回收卵137枚,回收率96.48%,可用胚126枚,移植鲜胚126枚,移植受体羊97只,受胎率56.7%。2004～2005年超排处理特克赛尔供体母羊46只,查黄体485个,采用子宫冲胚技术回收卵403枚,回收率83.09%,有效胚327枚,移植鲜胚217枚,鲜胚移植受体羊186只,受胎率54.92%;制作冻胚110枚,移植冻胚104枚,冻胚移植受体羊80只,未返情受体羊数41只,受胎率51.25%。     

布尔山羊胚胎移植试验研究

2001年9-12月份，应用2种超排方案对35只布尔山羊（其中经产羊30只，处女羊5只）进行了超排处理，并对180只受体进行了胚胎移植。结果表明：35只供体共回收胚胎471枚，可用胚为349枚，可用胚胎率为74.10％（349/471），每只平均获胚胎11.91枚，只均可用胚9.97枚。其中经产羊30只，平均每只获胚胎12.43枚，只均可用胚胎10.37枚；处女羊5只，平均每只获胚胎8.8枚，只均可用胚胎7.6枚。鲜胚移植受体180只，每只1枚，妊娠率为63.89％（115/180），另外，试验表明，不同剂量的FSH对超排效果也有一定的影响。     

Seroprevalence and epidemiological correlates of HTLV-I infection in U.S. blood donors

Screening for human T-lymphotropic virus type I (HTLV-I) antibodies was performed on sera from 39,898 blood donors at eight blood centers in geographically distinct areas of the United States. Ten donors (0.025 percent) showed evidence of HTLV-I seropositivity by enzyme immunoassays; this was confirmed by protein immunoblot and radioimmunoprecipitation. Seroprevalence rates ranged from 0 to 0.10 percent at the locations sampled, with HTLV-I antibodies found predominantly in donors from the southeastern and southwestern United States. Matched case-control interviews and laboratory studies were performed on five seropositive women and two seropositive men who participated in an identity-linked collection of sera from a subset of 33,893 donors at six of the eight blood centers. Four of the women and both men are black; one woman is Caucasian. Four of the seven seropositive individuals admitted to prior intravenous drug abuse or sexual contact with an intravenous drug user. Sexual contact with native inhabitants of an HTLV-I endemic area was the only identified risk factor for one male. The distribution of HTLV-I antibodies in this U.S. blood donor sample corroborates the previously reported epidemiology of this agent and suggests that additional donor screening measures, including the testing of donated blood for HTLV-I markers, may be necessary to prevent the spread of HTLV-I to transfusion recipients.     

促性腺激素促进雄性小鼠体内卵巢移植体卵泡卵母细胞生长发育的研究

 【目的】探索外源促性腺激素对卵巢在雄性受体内生长、卵泡发育和卵母细胞成熟与发育能力的影响。【方法】将1日龄小鼠卵巢移植到7～12周龄雄性小鼠肾囊下,回收前用促性腺激素对受体进行处理或不处理,同龄雌性小鼠用促性腺激素进行处理后作为对照。移植21 d后回收移植卵巢,观测移植体的回收率及生长和卵泡发育;对卵母细胞进行体外成熟、体外受精,观察2-细胞胚和囊胚发育率。【结果】移植21 d后,未处理组移植体回收率为85.4%,与处理组（90.7%）差异不显著（P＞0.05）。未处理组移植体卵泡发育至成熟阶段,回收卵母细胞均处在GV期,平均每枚移植体回收卵母细胞数为（41.4±25.8）枚,2-细胞胚胎发育率为17.5%,未能发育至囊胚;处理组移植体有黄体形成,有的卵泡中有扩展的卵丘卵母细胞复合体,平均回收卵母细胞数为（33.4±20.1）枚,其中MⅡ期卵母细胞为（8.5±7.1）枚,GV期、MⅡ期卵母细胞受精后2-细胞胚胎的发育率分别为33.9％和44.3%,囊胚发育率分别为0.48%和6.3%;试验组间回收卵母细胞数差异不显著（P＞0.05）,2-细胞胚胎发育率、囊胚发育率差异极显著（P＜0.01）。试验组卵母细胞2-细胞胚胎发育率显著低于对照组（P＜0.01）,处理组MⅡ期卵母细胞囊胚发育率与对照组差异不显著（P＞0.05）。【结论】外源促性腺激素对雄性小鼠卵巢移植体具有促进卵泡发育、卵母细胞成熟和胚胎发育的作用,但不增加卵母细胞产量。     

Prevention of allogeneic bone marrow graft rejection by H-2 transgene in donor mice

Rejection of bone marrow grafts in irradiated mice is mediated by natural killer (NK) cells and is controlled by genes linked to the major histocompatibility complex (MHC). It has, however, not been possible to identify the genes or their products. An MHC class I (Dd) transgene introduced in C57BL donors prevented the rejection of their bone marrow by NK cells in irradiated allogeneic and F1 hybrid mice expressing the Dd gene. Conversely, H-2Dd transgenic C57BL recipients acquired the ability to reject bone marrow from C57BL donors but not from H-2Dd transgenic C57BL donors. These results provide formal evidence that NK cells are part of a system capable of rejecting cells because they lack normal genes of the host type, in contrast to T cells, which recognize cells that contain abnormal or novel sequences of non-host type.     

Prolonged survival of second human kidney transplants

Rejection of kidney transplants in 264 patients, followed by retransplantation from cadaver donors, resulted in a 1-year survival rate of 51 +/- 3 percent (rate +/- standard error) as compared to 51 +/- 1 percent for first transplants. If the first transplant immunizes the patient or is rejected by immunologically responsive patients, second grafts into the same patients would be expected to be rejected at a higher rate. Only those reject who reject first grafts hyperacutely or between 1 to 3 months were found to have low second graft survival rates. Patients who rejected transplants after 3 months tended to have second transplant survival rates which were higher than their first graft survival rates.     

波尔山羊批量胚胎移植莎能奶山羊

采用阴道栓 FSH超数排卵,经产供体波尔山羊22只,在放栓后第9～11天,连续4d递减量肌肉注射FSH。22只供体羊发情与纯种波尔山羊种公羊配种后第7天,手术回收输卵管中早期发育胚胎再经手术移入同期发情的受体奶山羊输卵管内妊娠产仔。结果表明:1获得373枚早期胚胎,其中A级胚胎占31.1%(85/273),B级胚胎占49.5%(135/273),异常胚胎占19.4%(53/273)。2将167枚7日龄可用胚胎(A级和B级)移植147只受体羊输卵管内,移植后35d,妊娠98只,妊娠率为67%(98/147),83只羊足月产羔为89只,产羔率为85%(89/98),20只受体移植了两枚胚胎,只有6只产双羔。3羔羊出生重平均为3.7±0.54kg。每只供体羊平均产羔4.05只。胚胎移植所得羔羊的初生重与自然繁殖波尔羔羊无显著差异(P>0.05)。试验证明,山羊胚胎移植计划可使良种群体繁殖率提高3～5倍,优秀个体繁殖力提高6～8倍,从而加快纯种山羊的繁殖。     

小型农牧场及农户波尔山羊胚胎移植关键技术研究

从小型农牧场及农户特点出发,探讨在这些场(户)进行波尔山羊胚胎移植时,供体超数排卵、受体同期发情、供受体羊胚胎回收和移植操作等关键技术对胚胎移植效率的影响。结果表明,调整供、受体母羊的发情周期并采用优化超排程序和同期发情程序,可获得理想的超排和同期发情结果,有效手术供体回收卵数平均达到(17.31±6.93)枚,可用胚(14.96±6.28)枚;受体同期发情率达到94.28%(2125/2254),手术受体利用率为86.55%(1602/1851)。严格而熟练的手术操作可提高供体利用次数,获得理想的胚胎移植结果,将2648枚胚胎移植给1602只受体后,妊娠率达到66.85%(1071/1602),其中1044只受体妊娠足月,产羔1320只。     

波尔山羊胚胎移植研究报告

该研究受体羊（杂交奶山羊）１８４只,供体波尔母羊７６只。通过同期发情处理,７６只羊共排卵７２６个,其中受精卵３８７,占据排卵总数的５３．３１％。在受精卵中,有效胚３５３个,其中一级胚３１２个,二组胚４１个。共移植１８４只受体羊,基本正常产羔的受体母羊１０５只,占移植受体羊总数的５７．０７％。在受体母羊中,９７只移植２个胚胎,有５５只产双羔,占９７只受体羊的５６．７％。成活羔羊１５０只,其中公羊７８只,母羊７２只。公母羊平均出生重３．０５千克,最大出生重５．５千克。     

中国步甲类群在生物地理区系中的位置

我国纵跨古北界和东洋界,步甲区系繁荣。1990年,共已记录452属(亚属)和2076种(亚种、变种、型),分别占全球步甲属、种的11.24％和6.92％～8.3％。其中,广分布属27.89％,中国特有属6.34％。区域性分布种和窄分布种约97％;古老类群及其后裔20.65％,较年轻的类群约6.34％。     

Crash development of AIDS test nears goal

Impending development of a blood test for AIDS has paved the way for an epidemiological study by the National Heart, Lung and Blood Institute. Blood samples from 200,000 presumably healthy donors will soon be drawn and stored, to be screened when the test becomes available. Donors and recipients of blood which tests AIDS-positive will then be followed to see if AIDS develops. The study raises ethical issues in the areas of obtaining informed consent from donors and notifying donors and recipients of test results. The plan now is to obtain consent from donors and notify them of positive test results, and to decide later about notifying recipients.     

Mixed lymphocyte reactions and tissue transplantation tolerance

The induction of tolerance of Lewis histocompatibility antigens in BN rats inoculated at birth with BNI Lewis F(1) hybrid bone marrow cells, as revealed by the prolonged survival of Lewis skin grafts, is accompanied by markedly decreased reactivity in the mixed lymphocyte interaction. Blood lymphocytes from animals inoculated with lymph node cell suspensions also display diminished proliferative reactivity to hybrid BN/Lewis cells in the interaction. However, these recipients are not tolerant of Lewis skin grafts. Blood lymphocytes from BN rats inoculated neonatally with Lewis thymocytes fail to display any level of unresponsiveness in vitro, and such animals are not tolerant of Lewis skin grafts. The results suggest that in rats skin and marrow cells have histocompatibility antigens that are absent or poorly expressed on lymph node cells and thymocytes.     

家兔细胞核移植技术研究

以家兔16－32细胞期胚胎卵裂为核供体，显微注射到去核卵母细胞周隙中，共制作完成229枚重组胚，2次电融合后率达到76．8％。重组胚与兔胚成胎成纤维细胞共同培养，卵裂率为65．7％（23／35），桑囊率达到22．9％（8／35），均显著高于（P＜0．01）微滴直接培养结果（43．3％、13／30；16．7％，5／30）。将111枚重组胚手术移植到9只同期发情的受体母兔输卵管中，2只妊娠，其中1只完成足月胚胎发育产出克隆仔兔2只。     

家兔板层角膜移植及效果观察

在普通手术条件下,对8只白色青年家兔(4只供体和4只受体)进行了板层角膜移植手术;在4只受体兔中,A兔和D兔采用连续缝合法,B兔和C兔采用间断缝合法。观察发现,4只受体兔均有抓挠眼部和互相舔眼现象;A兔在术后第6天突然死亡,但角膜植片完好,剖检见肠道出血;B兔和C兔分别在术后第6天和第8天角膜植片脱落,但无明显炎症反应;D兔到术后第15天时角膜完全透亮,整个缝线清晰可见,分辨不出植片边缘,第16天拆除缝合线。结果表明,兔角膜移植的术后护理很难,原因是他们不仅没有自我保护意识,反而有自我伤害行为;B兔和C兔的植片脱落与瞬膜摩擦、抓挠眼部和互相舔眼有很大关系。     

Conservation of Potassium in the Pinus resinosa Ecosystem

Rubidium-potassium ratios were determined on foliage, litter, and surface soils of plots in two plantations of Pinus resinosa 41 to 46 years old previously fertilized once with potassium. Calculations based on indigenous soil rubidium as the "tagging" ion demonstrate that after 9 years some 60 percent of the foliage potassium is still derived from the fertilizer, and after 23 years about 40 percent of the foliage potassium is derived from the fertilizer. Additional fertilizer potassium is present in soil and litter, indicating the high retention of this mobile element in the pine ecosystem.     

枇杷叶片越冬期光合色素及矿质营养含量的变化

以枇杷品种解放钟为材料,对越冬期(2002年11月至2003年2月)叶片光合色素及矿质营养含量的变化进行了研究.结果表明,越冬过程中解放钟枇杷幼叶、成熟叶及老叶叶绿素b含量逐渐下降,而叶绿素a、叶绿素a b及类胡萝卜素(Car)含量先增加后下降,2月份其含量降至最低.11月份至翌年1月份叶片叶绿素a、叶绿素b、叶绿素a b及Car含量为:老叶>成熟叶>幼叶;2月份叶片叶绿素a b含量及叶绿素a/b表现为:成熟叶>老叶>幼叶.幼叶叶绿素a b含量大幅度降低是叶绿素a含量下降的结果.叶片N、P含量表现为先上升后下降,至2月份降至最低;成熟叶及老叶K含量保持相对稳定;叶片中Ca、Fe含量呈增加趋势,且老叶>成熟叶>幼叶;而幼叶Mg含量略高于老叶和成熟叶.枇杷成熟叶和老叶光合色素及叶片N、P、K、Ca、Fe含量的变化可能是其对冬季适应性的生理反应.     

饲粮赖氨酸和蛋氨酸水平对幼龄雉鸡生产性能的影响

采用二因素二次回归正交设计 ,研究了饲粮Lys和Met水平对 0～ 8周龄雉鸡生产性能的影响。结果表明 :饲粮Lys和Met水平对生产性能的影响均呈二次曲线变化 ;极显著影响雉鸡的增重 ,二者之间存在显著的交互作用 ;饲粮Lys对料肉比影响不显著 ;Met水平极显著影响 0～ 4和 0～ 8周龄 ,而显著影响 4～ 8周龄的料肉比 ;饲粮Lys和Met之间对料肉比的交互作用在 0～ 4周龄显著 ,在 4～ 8和 0～ 8周龄不显著。 0～ 4周龄获最佳生产性能需Lys和Met分别为 1 5 6 0 %和 0 5 78% ,4～ 8周龄分别为 1 15 4%和 0 45 2 % ,0～ 8周龄分别为 1 2 6 0 %和 0 5 0 1%。