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71.
Laura Telford Scott H. Seidman Gary D. Paige 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1998,118(1):115-125
Natural head movements include angular and linear components of motion. Two classes of vestibulo-ocular reflex (VOR), mediated
by the semicircular canals and otoliths (the angular and linear VOR, or AVOR and LVOR, respectively), compensate for head
movements and help maintain binocular fixation on targets in space. In this study, AVOR/LVOR interactions were quantified
during complex head motion over a broad range of fixation distances at a fixed stimulus frequency of 4.0 Hz. Binocular eye
movements were recorded (search-coil technique) in squirrel monkeys while fixation distance (assessed by vergence) was varied
using brief presentations of earth-fixed targets at various distances. Stimuli consisted of rotations around an earth-vertical
axis and therefore always activated the AVOR. Horizontal and vertical AVORs were assessed when the head was centered over
the axis of rotation and oriented upright (UP) and right-side-down (RD), respectively. AVOR gains increased slightly with
increasing vergence in darkness, as expected given the small anterior position of the eyes in the head. Combined AVOR/LVOR
responses were recorded when subjects were displaced eccentrically from the rotation axis. Eccentric rotations activated the
AVOR just as when the head was centered, but added a translational stimulus which generated an LVOR component in response
to interaural (IA) or dorsoventral (DV) tangential accelerations, depending on whether the head was UP or RD, respectively.
When the head was eccentric and facing nose-out, the AVOR and LVOR produced ocular responses in the same plane and direction
(coplanar and synergistic), and response magnitudes increased with increasing vergence. With the head facing nose-in, AVOR
and LVOR response components were oppositely directed (coplanar and antagonistic). The AVOR dominated the response when fixation
distance was far, and phase was compensatory for head rotation. As fixation distance decreased toward the rotation axis, responses
declined to near zero, and when fixation distance approached even closer, the LVOR component dominated and response phase
inverted. The same pattern was observed for both horizontal (head UP) and vertical (head RD) responses. The LVOR was recorded
directly by rotating subjects eccentrically but in the nose-up (NU) orientation. The AVOR then generated torsional responses
to head roll, coexistent with either horizontal or vertical LVOR responses to tangential acceleration when the subject was
oriented head-out or right-side-out, respectively. Only the LVOR response components were modulated by vergence. A vectorial
analysis of AVOR, LVOR, and combined responses supports the conclusion that AVOR and LVOR response components combine linearly
during complex head motion.
Received: 27 February 1997 / Accepted: 18 June 1997 相似文献
72.
目的:利用大肠杆菌表达系统表达人血管抑制因子,并利用镍金属螯合层析法进行纯化,探讨其抑制血管内皮细胞增殖的活性。方法:采用RT-PCR技术从人肝脏组织中获取人血管抑制因子的cDNA,将其克隆至原核表达载体pQE30中进行IPTG诱导表达。表达产物经SDS-PAGE分析,并利用镍金属螯合层析法进行纯化。^3H-TdR法检测纯化的血管抑制因子对血管内皮细胞增殖的抑制作用。结果:利用pQE30表达载体表达的含6个组氨酸尾的vasostafin蛋白,在SDS-PAGE上表现出一条约2lkD的阳性条带,经镍金属螯合层析纯化后的蛋白经肽指纹图谱分析鉴定为目的蛋白,在体外可抑制人脐静脉血管内皮细胞的增殖。结论:人血管抑制因子可在大肠杆菌中以包涵体形式高水平表达,并具有抑制血管内皮细胞增殖的活性. 相似文献
73.
目的:为设计阴部外动脉阴茎皮瓣转位尿道成形术提供依据。方法:30侧经动脉内灌注红色乳胶的成人尸体,解剖观测阴部外动脉起始、行程;着重阴部外动脉阴茎支在阴茎的走行、分支分布。结果:阴部外动脉始于股动脉,外径1.8±0.4mm,伴行静脉1-2支,汇入大隐静脉。阴茎支可视为本干的延续,经耻骨结节两侧靠近阴茎,分别经2(10)点、3(9)点和1(11)点进入阴茎,多数分出背侧支、腹侧支分布阴茎皮肤。外径0.8±0.2mm。结论:阴茎皮肤血管恒定,以阴茎支为蒂,可在阴茎外侧或背外侧、腹外侧设计皮瓣,用于尿道成形术。术式已在临床应用,效果满意。 相似文献
74.
75.
目的:为研制蝰蛇毒压电免疫传感器,研究抗蛇毒抗体固定于石英晶体银电极表面的固定技术。方法:采用马抗蝰蛇毒血清抗体和抗蝰蛇毒鸡卵黄抗体作为生物敏感材料,对比研究了胱胺自组装-PSS反相吸附法和PEI粘附-戊二醛交联法:比较了采用两种固定方法所制的压电免疫传感器的性能。结果:鸡卵黄抗体采用PEI粘附-戊二醛交联法效果较好,其制备的IgY压电免疫传感器检测蝰蛇毒灵敏度为0.5ug/mL;而马血清抗体用胱胺自组装-PSS反相吸附法较好,其制备的IgG’免疫传感器检测蝰蛇毒灵敏度为10ug/mL。结论:以PEI粘附-戊二醛交联法固定抗蝰蛇毒鸡卵黄抗体所制备的蝰蛇毒压电免疫传感器的性能稳定,特异性好,可实现蛇毒的快速检测。 相似文献
76.
Hisao Kondo Midori Miura Yoshinori Itokawa 《Pflügers Archiv : European journal of physiology》1993,422(4):404-406
To clarify the mechanism of oxidative stress in skeletal muscle atrophied by immobilization, we investigated the change of antioxidant enzyme activities in a typical slow red muscle, the soleus. Atrophied soleus muscles were collected from male Wistar rats (16 weeks old), one ankle joint of which had been immobilized in the fully extended position for 7 days. Also, soleus muscles were collected from intact age-matched rats as control. The activities of Mn-containing superoxide dismutase (Mn-SOD), Cu,Zn-containing superoxide dismutase (Cu,Zn-SOD), Se-dependent glutathione peroxidase (Se-GSHPx), glutathione S-transferase (GST), catalase, and glutathione reductase (GSSGRx) were measured. The activities of Cu,Zn-SOD, GST, and GSSGRx were significantly higher in atrophied muscles, while the others were unchanged. Increased Cu,Zn-SOD and unchanged Mn-SOD levels might reflect increased generation of superoxide anions in the cytoplasm rather than in the mitochondria. Owing to the enhancement of Cu,Zn-SOD and the unaltered Se-GSHPx and catalase activities, hydrogen peroxide is thought to be increased in the cytoplasm. Because there is also an increase of iron in the microsomes of atrophied muscles, the production of hydroxyl radicals, the most aggressive of radicals, might consequently be elevated. 相似文献
77.
Laboratory of Experimental Surgery, A. V. Vishnevskii Institute of Surgery, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR M. I. Kuzin.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 111, No. 6, pp. 617–619, June, 1991. 相似文献
78.
Shibahara H Tsunoda T Taneichi A Hirano Y Ohno A Takamizawa S Yamaguchi C Tsunoda H Sato I 《American journal of reproductive immunology (New York, N.Y. : 1989)》2002,47(3):146-150
PROBLEM: The presence of antisperm antibodies (ASA) in males can reduce fecundity, however, relationship between the two is disputed. This study was performed to investigate if there is diversity of ASA bound to sperm surface using immunobead test (IBT) combined with complement dependent sperm immobilization test (SIT). METHODS: The ASA bound to sperm surface were detected using the direct IBT (D-IBT) in 275 semen samples. In some cases with ASA detected by D-IBT, sperm immobilizing antibodies bound to sperm surface were also evaluated using direct SIT (D-SIT). RESULTS: The incidence of the immunoglobulin G (IgG), IgA, and IgM classes of ASA detected by D-IBT were 2.5, 1.8, and 0.4%, respectively. Totally, nine (3.3%) infertile men had ASA on the sperm surface. D-SIT was tested positive in four (66.7%) of six cases with ASA assessed by D-IBT. CONCLUSIONS: Some of the sperm-bound antibodies are associated with complement dependent sperm immobilizing antibodies, indicating that there exists a heterogeneity of sperm-bound antibodies. This result might be one of the reasons for the controversy about the relationship between ASA and immunological infertility in men. 相似文献
79.
Yanagida K Katayose H Hirata S Yazawa H Hayashi S Sato A 《Human reproduction (Oxford, England)》2001,16(1):148-152
Sperm immobilization prior to intracytoplasmic sperm injection (ICSI) is thought to be necessary for efficient fertilization. A variety of methods of sperm immobilization (pipetting, squeezing and piezo application) are currently employed in ICSI. The effect of differences in immobilization method on the timing of initial Ca(2+) oscillations of oocytes in ICSI was investigated. Motile spermatozoa were immobilized in eosin Y solution using pipetting, squeezing and piezo application. Complete staining of the sperm head was achieved after 220.7, 42.2 and 5.0 s respectively. Oscillations after ICSI were measured fluorometrically for each method. The onset of Ca(2+) oscillations was observed at 4.8 to 80.4 min after ICSI. Ca(2+) oscillations developed earlier with the piezo method (14.4 +/- 6.4 min) than other methods (pipetting, 43.1 +/- 20.2 min, P < 0.01; squeezing, 18.4 +/- 3.8 min, P = NS). The piezo method produced the earliest staining of the sperm head and may have caused the most damage to the sperm membrane. A more rapid onset of Ca(2+) oscillations was also observed with the piezo method. The method of sperm immobilization may be important for the rapid release of sperm factors that initiate oocyte activation. This study also showed that Ca(2+) oscillations develop earlier in human oocytes treated by ICSI than indicated in previous reports. 相似文献
80.
Yamamoto N Yang M Jiang P Xu M Tsuchiya H Tomita K Moossa AR Hoffman RM 《Clinical & experimental metastasis》2003,20(7):633-638
We have established stable, bright green fluorescent protein (GFP)- or red fluorescent protein (RFP)-expressing HT-1080 human
fibrosarcoma clones. These cell lines showed similar cell proliferation rates and high-frequency experimental lung metastasis.
The HT-1080-GFP and -RFP clones enable simultaneous real-time dual-color imaging in the live animal. HT-1080 cells were transduced
with retroviral vectors containing GFP or RFP and the neomycin resistance gene. Stable transformants were selected stepwise
with G418 up to 800 μl/ml. Subsequently, high GFP- or RFP-expressing clones, HT-1080-GFP or HT-1080-RFP, respectively, were
selected. 3×106 cells from each clone were mixed and injected into the tail vein of SCID mice. The cells seeded the lung at high frequency
with subsequent formation of pure green and pure red colonies as well as mixed yellow colonies with different patterns visualized
directly on excised lungs. The lung metastases were also visualized by external fluorescence imaging in live animals through
skin-flap windows over the chest wall. Lung metastases were observed on the lung surface of all mice. SCID mice well tolerated
multiple surgical procedures for direct-view imaging via skin-flap windows. Real-time metastatic growth of the two different
colored clones in the same lung was externally imaged with resolution and quantification of green, red, or yellow colonies
in live animals. The color coding enabled determination of whether the colonies grew clonally or were seeded as a mixture
with one cell type eventually dominating, or whether the colonies grew as a mixture. The simultaneous real-time dual-color
imaging of metastatic colonies described in this report gives rise to the possibility of color-coded imaging of clones of
cancer cells carrying various forms of gene of interest.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献