入侵种喜旱莲子草和莲子草的营养生长和光合作用对温度的响应

比较温度对入侵种喜旱莲子草(Alternantheraphiloxeroides(Mart.)Griseb.)和其本土近缘种莲子草(A.sessilis(L.)DC.)的营养生长、叶片光合作用及叶绿素荧光的影响。实验将生长均衡的这两种植物放在不同温度(10℃、15℃、20℃、25℃、30℃)的光照培养箱中处理28d。结果表明,喜旱莲子草营养生长的速率和对温度的响应明显不同于莲子草:前者主茎生长的有效积温明显低于后者,分别是11.6d℃和27.0d℃;而新叶萌发的有效积温高于后者,分别是12.1d℃和6.7d℃。入侵种主茎和叶的发育起点温度都比本土种低,分别是10.4℃、11.0℃和12.8℃、14.9℃,表明喜旱莲子草的发育对低温反应不及莲子草敏感。对两种植物叶片的光合作用和叶绿素荧光的测定结果还表明:入侵种比本土种有较高的最大净光合速率和光饱和点,尤其在25℃时;10-30℃的温度范围内喜旱莲子草的最大光化学效率Fv/Fm没有显著变化,而莲子草在10℃低温条件下Fv/Fm值显著降低。较快的主茎生长速率、较宽的温度适应范围以及较高的光合能力可能使喜旱莲子草比本地种具有更强的竞争力,从而在其入侵过程中起了重要作用。     

玉米叶片生长部位渗透调节和生长的生物物理参数变化

玉米叶片生长部位随着水分胁迫加剧ψ_w降低、LER减慢。LER从最大到零,快速干旱处理的ψw从-0.55降至-0.85 MPa;缓慢干旱处理ψ_w从-0.88降至-1.13 MPa。在任何一种LER下,缓慢干旱处理的ψ_s比快速干旱处理更低,生长停止时,前者为-1.57 MPa,而后者为-1.30MPa。缓慢干旱叶片尽管在更低ψ_w下,仍能维持一定膨压,保持一定的生长速率。经历长时间水分胁迫会改变细胞延伸生长的生物物理参数,增大临界膨压(0.08～0.09 MPa)。这是水分胁迫植株,在一定ψ_p下生长速率减慢的原因。     

Enhancement of colonic motor response to feeding by central endogenous opiates in the dog

The role of endogenous opiates in the colonic motor response to feeding has been investigated in four dogs chronically fitted with two strain gages on the proximal and distal colon and a cannula in cerebral lateral ventricle. A daily meal stimulated the colonic motility during 8-10 hrs. The colonic motility index was significantly higher during this period when an enkephalinase inhibitor, tiorphan, was intracerebroventricularly (i.c.v.) administered at a dose of 0.1 mg/kg before the meal. This effect was blocked by a previous i.c.v. administration of naltrexone (0.1 mg/kg) and reproduced by (D-Ala2, Met5) enkephalinamide (DALAMIDE) at a dose of 50 mg/kg. I.c.v. administration of tiorphan or DALAMIDE did not modify the colonic motility in dogs fasted for 48 hrs. The postprandial motility index remained unchanged after intravenous administration of tiorphan or DALAMIDE at the same dosages. These results provide evidence for a central control of the colonic motor response to feeding by endogenous enkephalins in dogs.     

Recombinant disintegrin targets α(v) β(3) integrin and leads to mediator production

Integrin αvβ3 is most likely the foremost modulator of angiogenesis among all known integrins. Recombinant disintegrin DisBa-01, originally obtained from snake venom glands, binds to αvβ3, thereby significantly inhibiting adhesion and generating in vivo anti-metastatic ability. However, its function in mediator production is not clear. Here, we observed that the mediators VEGF-A, IL-8, and TGF-β are not produced by human umbilical vein endothelial cells (HUVEC cell line) or monocyte/macrophage cells (SC cell line) when cells adhered to vitronectin. However, when exposed to DisBa-01, HUVECs produced higher levels of TGF-β, and SC cells produced higher levels of VEGF-A. Nonetheless, HUVECs also showed an enhancement of apoptosis after losing adherence when exposed to disintegrin, which is a characteristic of anoikis. We propose that disintegrin DisBa-01 could be used to modulate integrin αvβ3 functions.     

关于神经病学PBL教学中心理因素的思考

神经病学是涉及多个基础学科的临床专门学科,其内容复杂抽象,令学生望而生畏。PBL是学生自主学习建构知识和教师引导的教学模式,有利于学生克服畏难情绪,提高学习效率。根据我们的实践体会,教师与学生的心理是影响PBL教学效果的重要因素。只有把握好教学过程中的心理因素,才能使PBL的优势真正得以体现。     

Wistar大鼠幼年期丰富环境刺激对其社会竞争行为的影响

目的：探讨大鼠幼年期丰富环境经历对其成年后焦虑样行为和社会竞争行为的影响。方法：幼年期Wistar大鼠（生后21天）分为标准饲养组（对照组）和丰富环境刺激（EE）组。对照组为持续在标准实验室饲养条件下饲养;丰富环境组为生后21天至行为学检查时持续在丰富环境下饲养。在生后70天进行行为学检测：采用高架十字迷宫方法测试焦虑样行为;采用社会优势管道试验观察社会竞争性行为。结果：高架十字迷宫实验结果显示,与对照组相比,丰富环境组在开放臂的时间和次数显著增加;优势管道实验结果显示丰富环境刺激组大鼠的社会竞争力明显下降。结论：大鼠幼年期丰富环境刺激可改善大鼠的焦虑样情绪,但导致大鼠社会竞争力下降。     

液质连用分析重组胰高血糖素样肽-1受体激动剂肽图

目的：建立高效液相系统肽图分析法,用于重组胰高血糖素样肽-1受体激动剂（rExendin-4）的质量控制。方法：应用高效液相系统摸索最佳胰蛋白酶切和色谱条件,并采用液质联用系统分析肽段的精确相对分子量和氨基酸序列。结果：根据酶切条件摸索,确定酶切条件为：rExendin-4原液与胰蛋白酶按照质量比为100：1混匀,37℃酶切4小时,根据肽段的色谱保留时间、相对分子质量及对其碰撞诱导解离质谱的解析结果,归属出肽图中各肽段所在的色谱峰,与理论值完全一致。结论：本法精确度高、重复性好、自动化程度高,能够用于rExendin-4原液肽图分析。     

Toll‐like receptor 9 protects non‐immune cells from stress by modulating mitochondrial ATP synthesis through the inhibition of SERCA2

Toll‐like receptor 9 (TLR9) has a key role in the recognition of pathogen DNA in the context of infection and cellular DNA that is released from damaged cells. Pro‐inflammatory TLR9 signalling pathways in immune cells have been well investigated, but we have recently discovered an alternative pathway in which TLR9 temporarily reduces energy substrates to induce cellular protection from stress in cardiomyocytes and neurons. However, the mechanism by which TLR9 stimulation reduces energy substrates remained unknown. Here, we identify the calcium‐transporting ATPase, SERCA2 (also known as Atp2a2), as a key molecule for the alternative TLR9 signalling pathway. TLR9 stimulation reduces SERCA2 activity, modulating Ca²⁺ handling between the SR/ER and mitochondria, which leads to a decrease in mitochondrial ATP levels and the activation of cellular protective machinery. These findings reveal how distinct innate responses can be elicited in immune and non‐immune cells—including cardiomyocytes—using the same ligand‐receptor system.     

不同粘度对比剂对冠状动脉造影患者肾功能的影响

目的：对比剂肾病（CIN）是介入治疗中常见并发症之一。由于对比剂肾病发病机制复杂,其确切的机制尚不明确,有研究认为应用渗透压相似的对比剂,高粘度组对比剂引起CIN的几率明显高于低粘度组。本研究探讨接受不同粘度对比剂冠状动脉造影检查的患者术后引起肾功能损害的差异及其可能的机制。方法：80例接受冠状动脉造影检查的患者随机分为两组。分别为20℃碘海醇组、37℃碘海醇组,每组各40例。分别于冠脉造影前8h、冠脉造影后48h采集同一患者肘正中静脉血进行血清肌酐（Scr）、血清胱抑素C（CysC）检测,并对数据进行统计学分析。结果：两组患者组间比较基本资料无明显差异,两组患者术后Ser、CysC较术前均升高,差异均有统计学意义（P〈0．05）;20℃碘海醇组术后Scr较37℃碘海醇组升高不明显,差异无统计学意义（P〉0．05）;20℃碘海醇组术后CysC较37℃碘海醇组升高明显,差异有统计学意义（P〈0．05）。结论：冠脉造影检查时．对比剂对患者的肾功能有损害;选择低粘度对比剂可能减少其对冠状动脉造影患者的肾功能的不良影响;其作用机制可能与对比剂改变血液粘滞性,从而影响肾血流有关。     

C-type lectin-like molecule-1 (CLL1)-targeted TRAIL augments the tumoricidal activity of granulocytes and potentiates therapeutic antibody-dependent cell-mediated cytotoxicity

The therapeutic effect of anti-cancer monoclonal antibodies stems from their capacity to opsonize targeted cancer cells with subsequent phagocytic removal, induction of antibody-dependent cell-mediated cytotoxicity (ADCC) or induction of complement-mediated cytotoxicity (CDC). The major immune effector cells involved in these processes are natural killer (NK) cells and granulocytes. The latter and most prevalent blood cell population contributes to phagocytosis, but is not effective in inducing ADCC. Here, we report that targeted delivery of the tumoricidal protein tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) to granulocyte marker C-type lectin-like molecule-1 (CLL1), using fusion protein CLL1:TRAIL, equips granulocytes with high levels of TRAIL. Upon CLL1-selective binding of this fusion protein, granulocytes acquire additional TRAIL-mediated cytotoxic activity that, importantly, potentiates antibody-mediated cytotoxicity of clinically used therapeutic antibodies (e.g., rituximab, cetuximab). Thus, CLL1:TRAIL could be used as an adjuvant to optimize the clinical potential of anticancer antibody therapy by augmenting tumoricidal activity of granulocytes.