Pre‐copulation intervals,copulation frequencies,and initial progeny sex ratios in two biotypes of whitefly,Bemisia tabaci

The whitefly Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae) is a species complex, and its systematic classification requires controlled crossing experiments among its genetic groups. Accurate information on pre‐copulation intervals, copulation frequencies, and initial frequency of egg fertilization of newly emerged adults is critical for designing procedures for collecting the virgin adults necessary for these experiments. In the literature, considerable variation is reported between B. tabaci populations, with respect to the length of the pre‐copulation interval and the initial frequency of egg fertilization. Here, we used a video‐recording method to observe continuously the copulation behaviour of the Mediterranean/Asia Minor/Africa (B biotype) and the Asia II (ZHJ1 biotype) groups of B. tabaci. We also recorded the initial frequency of egg fertilization, as determined by the sex of the progeny. When adults were caged in female–male pairs on leaves of cotton plants, the earliest copulation events occurred 2–6 h after emergence; at 12 h after emergence 56–84% of the females had copulated at least once, and nearly all (92–100%) had copulated at least once by 36 h after emergence. Both females and males copulated repeatedly. Approximately 80 and 20% of copulation events occurred during the photophase and scotophase, respectively. By 72 h post‐emergence, the females of the B and ZHJ1 biotypes had copulated on average 6.1 and 3.9 times, respectively. When adults were caged in groups on plants 1–13 h after emergence, 30–35% of the eggs deposited during this period were fertilized, and approximately 90% of females were fertilized by the end of the 13 h. Although timing of copulation differed in detail between the two genetic groups, the results demonstrate that B. tabaci adults can start to copulate as early as 2–6 h post‐emergence and the majority of females can become fertilized on the day that they emerge.     

Differential Responsiveness in Zonal Growth of Cocklebur Seed Axes to CO2, C2H4, O2 and Respiration Inhibitors

The axial growth of de-coated cocklebur (Xanthium pennsylvanicumWallr.) seeds, whose axes were divided into 4 zones, was examinedin relation to the temperature-dependent shift of the effectof C₂H₄ on germination. At 23?C, where both C₂H₄ and CO₂ stimulatedgermination, CO₂ promoted the axial growth at the radicle tipzone, whereas C₂H₄ promoted growth in the proximal portion ofthe axis. At 33?C, C₂H₄ inhibited germination, and stronglysuppressed the growth at the radicle tip, whereas the effectof CO₂ did not change. The inhibition of growth at the radicletip zone was alleviated by O₂ enrichment, which also reversedthe inhibition of germination. It is thus apparent that thetemperature-dependent shift of the action of C₂H₄ is associatedwith a temperature-dependent responsiveness of the radicle tipzone to C₂H₄. Growth of the radicle tip zone was sensitive toNaN₃, whereas the proximal portion was sensitive to benzohydroxamicacid, an inhibitor of alternative respiration, suggesting thatthere may be an increase in the operation of the alternativerespiration path along a gradient of axial tissue from the tiptowards the cotyledonary side. The effects of CO₂ and C₂H₄ arediscussed in relation to the different respiratory activitiesin each axial zone of cocklebur seeds. (Received May 9, 1986; Accepted November 6, 1986)     

Identification of cellular mechanisms operational in vivo during the regression of established pulmonary metastases by the systemic administration of high-dose recombinant interleukin 2

The systemic administration of high-dose recombinant IL 2 mediated significant reductions of established 3-day pulmonary micrometastases from both weakly immunogenic and nonimmunogenic sarcomas. However, when treatment with IL 2 was delayed for 10 days after the injection of tumor cells in an attempt to treat grossly visible pulmonary macrometastases, only those established from weakly immunogenic sarcomas remained susceptible. Established 10-day pulmonary nodules from the nonimmunogenic sarcomas became refractory to IL 2 therapy. We utilized selective depletion of lymphocyte subsets in vivo by the systemic administration of specific monoclonal antibodies to cells bearing either the L3T4 or Lyt-2 marker or a heteroantiserum to cells bearing the ASGM-1 glycosphingolipid to identify lymphocytes involved in IL 2-induced tumor regression. Cells with potent lymphokine-activated killer (LAK) activity against fresh tumor targets in vitro were identified in the lungs of IL 2-treated mice. By flow cytometry analysis, the majority of these effector cells were Thy-1+, L3T4-, Lyt-2-, ASGM-1+. Depletion in vivo of ASGM-1+ cells before the onset of IL 2 administration eliminated the successful therapy of 3-day pulmonary metastases from nonimmunogenic sarcomas, with concurrent elimination of LAK cell activity in the lungs. In mice with 3-day pulmonary metastases from weakly immunogenic sarcomas, both Lyt-2+ cells and ASGM-1+ cells were involved in IL 2-mediated tumor regression, but Lyt-2+ cells appeared to be the more potent mediator in the response. Lyt-2+ cells were also involved in the elimination of grossly visible 10-day macrometastases from these weakly immunogenic tumors. Depletion of L3T4+ cells had no effect on tumor regression. Thus, although LAK effectors derived from ASGM-1+ precursors can eliminate pulmonary micrometastases regardless of tumor immunogenicity, Lyt-2+ cells are predominant effectors in the elimination of both pulmonary micro- and macrometastases from weakly immunogenic sarcomas.     

脑室注射P物质对大鼠血压、心率及交感传出活动的影响

给乌拉坦麻醉六鼠侧脑室注射P物质(SP)10μg,引起动脉血压、心率和内脏交感神经放电增加。同样剂量的SP静脉注射后却引起血压降低。阿托品预处理不影响SP的开心率作用。预先脑室注射0.25,4,64μg阿片受体拮抗剂纳洛酮,对SP的升压效应有剂量依赖式对抗作用。以上说明脑室注射SP 引起的血压升高是交感神经活动增强,导致心率加快及外周血管紧张性增加的结果,并提示SP的中枢升压效应可能与脑内释放内源性阿片样物质有关。     

Flow profiles and wall shear stress distribution at a hemodialysis venous anastomosis: preliminary study

The phasic velocity field in the vicinity of the venous anastomosis in a hemodialysis angioaccess arteriovenous fistula loop graft (AVLG) is investigated employing a laser Doppler anemometer (LDA) system. Detailed LDA velocity profiles are obtained by sectional survey performed in a transparent, elastic flow model which was fabricated to represent the geometry of the AVLG system under physiological pressure and flow waveforms. The geometry of the flow model was based on a silicone rubber cast obtained from an experimental dog model. In the present study, detailed distribution of velocity profiles is obtained. The distribution of wall shear stress in the model is computed from the slope of the local velocity profiles near the wall. The relationship between the results obtained by flow visualization and the LDA measurement is discussed.     

大鼠脑室注射P物质引起的血压升高与脑啡肽和β-内啡肽有关

给乌拉坦麻醉大鼠侧脑室注射P物质(SP)10μg 引起的升压效应,可被脑室注射纳洺酮15μg 部分阻断。将抗β-内啡肽抗血清、抗甲啡肽抗血清及抗亮啡肽抗血清各10μl 分别注入侧脑室预处理60min 后,再注入 SP,其升压效应明显减弱;而抗强啡肽抗血清则对其无影响。上述结果提示:大鼠脑室注射 SP 引起的升压效应,可能是通过释放β-内啡肽和脑啡肽实现的。     

Velocity distribution on the membrane of a tank-treading red blood cell

The kinematics of an area-conserving tank-treading disk-shaped red blood cell membrane is studied using the stream function method suggested by Secomb and Skalak (Q. Jl Mech. appl. Math. 35, Pt 2, 233–247, 1982). Two simple area-conserving velocity fields are superimposed to satisfy the continuity condition at the curved edges of the disk. A differential equation for the trajectory of any material point of the membrane is derived. The requirement of synchrony of the cycle for all membrane points leads to an integral equation which determines a magnitude function. An approximate solution is made possible by assuming small trajectory deflections.     

Distinct immunologic specificity of tumor regression mediated by effector cells isolated from immunized and tumor-bearing mice

Sensitized T lymphocytes can mediate potent antitumor effects when transferred to tumor-bearing animals. Employing the MCA 105 and MCA 106 sarcomas, we were able to generate antitumor effector cells by immunization of syngeneic mice with tumor cells admixed with Corynebacterium parvum. These immune splenocytes could be further sensitized and expanded in culture by the in vitro sensitization (IVS) method utilizing tumor stimulator cells and IL-2. Adoptive immunotherapy of pulmonary metastases mediated by noncultured splenocytes from immunized mice or immune IVS cells showed exquisite specificity between the two sarcomas. These results demonstrate the presence of tumor-specific antigens on MCA 105 and MCA 106 tumor cells which can serve as target molecules for immunotherapy. Recently, we have generated therapeutic T lymphocytes from mice bearing progressively growing tumors by the IVS method. However, IVS cells from tumor-bearing mice showed cross-reactivity between the MCA 105 and 106 sarcomas in adoptive immunotherapy experiments. Since these IVS cells did not affect other control tumors, the limited cross-reactivity suggests the presence of common tumor-associated antigens on MCA 105 and MCA 106 tumor cells which can also serve as the target for tumor rejection. Therefore, immune responses to progressive tumor growth and to immunization are distinct with respect to antigen recognition by T lymphocytes.     

左旋四氢巴马汀加强电针对兔大脑皮层牙髓诱发电位的抑制作用

家兔6只,用氨基甲酸乙酯和氯醛糖麻醉,电刺激牙髓,在对侧大脑皮层体感Ⅰ区引导其诱发电位,观察诱发电位各成分与痛的关系。结果观察到,在P1、N1、P2和 N2 4个波中,P1和 P2波相对稳定。其中,P2波(波峰潜伏期:66.1±1.9ms)具有较高的阈值,且不受无镇痛作用的中枢抑制剂安定的影响,而受小剂量镇痛剂度冷丁的抑制,提示 P2波与痛有关。以 P2波的波幅为指标,进一步在12只家兔上观察了 L-THP 和电针及两者合用对诱发电位的影响。结果显示,L-THP 和电针对诱发电位均有抑制作用,且两者在作用强度和时间上存在明显的协同,提示 L-THP 具有加强电针对兔大脑皮层牙髓诱发电位中痛相关成分的抑制作用。