电刺激兔脑干中缝背核引起呼吸易化效应的观察

本文在30只全麻、制动、断双侧迷走神经的家兔上,记录一侧膈神经放电,观察了电刺激脑干中缝背核(Nucleus Raphe Dorsalis,NRD)所诱发出的呼吸效应。1.施以6—10s 长串电脉冲刺激(波宽0.3ms,频率100Hz,波幅4—6V),诱发出了强的呼吸易化效应,使呼吸加深加快。2.吸气相给予0.4s 短串电脉冲刺激可以明显的延长吸气相,用0.15mA 强度刺激,落位在吸气相的2/3时效应最明显。3.呼气相短串电脉串刺激可规律地使呼气时程缩短,促进呼气向吸气的位相转换,诱发此效应出现的强度阈值在呼气相中逐渐降低。     

刺激黄雀新纹状体前部大细胞核外侧部对发声和呼吸的影响

实验材料为乌拉坦麻醉的鸣禽黄雀（Ｃａｒｄｕｅｌｉｓ ｓｐｉｎｕｓ）。观察了电及化学刺激新纹状体前部大细胞核外侧部（１ＭＡＮ）对发声和呼吸的影响。结果如下：（１）电刺激１ＭＡＮ的不同区域都引起鸣叫反应。（２）长串电脉冲刺激１ＭＡＮ使呼吸频率增加,呼吸幅度降低。（３）短串电脉冲刺激１ＭＡＮ,落位于吸气相,产生吸气要断效应;落位于呼气相,可使呼气时程延长,以冲刺激１ＭＡＮ,落位于吸气相,产生吸气切断效应     

燕雀上纹状体腹侧尾核对发声和呼吸的调制效应及其纤维联系

在乌拉坦麻醉的鸣禽燕雀（Ｆｒｉｎｇｉｌｌａｍｏｎｔｉｆｒｉｎｇｉｌｌａ）上,观察电刺激上纹状体腹侧尾核（ＨＶｃ）对发声和呼吸的影响,随后在ＨＶｃ内注入ＣＢ－ＨＲＰ溶液,研究ＨＶｃ的中枢联系。结果如下：（１）电刺激ＨＶｃ的不同区域都引起鸣叫反应。（２）长串电脉冲刺激ＨＶｃ,产生明显的呼吸易化效应,表现为增频增幅的呼吸。（３）吸气期用短串电脉冲刺激ＨＶｃ,产生吸气切断效应;刺激落位于呼气相,可使该呼气时程明显延长,以配合鸣叫,然后转变为增频增幅的呼吸。（４）ＣＢＨＲＰ法表明,ＨＶｃ投射到古纹状体粗核和嗅叶Ｘ区,ＨＶｃ接受新纹状体前部大细胞核内侧部、新纹状体中部界面核、端脑听核－Ｌ区、丘脑葡萄形核及脑桥蓝斑核的传入投射。提示ＨＶｃ除控制发声外,尚参与呼吸易化的调制。ＨＶｃ对发声及呼吸的特异性影响,可能在鸣叫与呼吸的协调机制中起重要作用。     

延髓腹外侧B(x)tzinger复合体呼吸时相转换效应的研究

实验在40只氨基甲酸乙酯麻醉的成年家兔上进行,观察电刺激Btzinger复合体(Bt.C)对呼吸节律的影响.结果表明: (1)吸气相早期短串电刺激Bt.C导致膈神经放电被短暂抑制,被抑制的程度与刺激强度呈正相关.当刺激落位在吸气相中、晚期时,可导致吸气提前终止("吸气切断"),之后跟随一缩短的呼气相.导致"吸气切断"的阈强度与刺激落位呈负相关.(2)呼气相短串电刺激Bt.C,可诱导膈神经短暂放电,呼气相晚期诱导出现放电之后往往跟随一正常的吸气放电,结果导致该呼气相缩短.该效应亦具有刺激强度、刺激落位依赖性.结果提示: Bt.C参与吸气向呼气以及呼气向吸气的时相转换.     

刺激家兔舌下神经核中段腹侧区对呼吸节律的影响

本工作在２５只氨基甲酸乙酯麻醉,断双侧迷走神经的家兔上,以膈肌肌电活动作为检测指标,观察了电及化学刺激舌下神经核中段腹侧区对呼吸节律的影响。结果如下：长串电脉冲刺激ＶＭＮＨ时,膈肌肌电活动被完全抑制,而颏舌肌活动明显易化;在吸气相的中期或后期短串电脉冲刺激ＶＭＮＨ可使吸气切断;微量注射谷氨酸钠于此区,膈肌活动也受到抑制。上述观察表明ＶＭＮＨ对呼吸节律具有调制作用,这种调制作用可能参与吞咽反射的中枢     

延髓腹外侧Btzinger复合体呼吸时相转换效应的研究

实验在４０只氨基甲酸乙酯麻醉的成年家兔上进行，观察电刺激Ｂ¨ｏｔｚｉｎｇｅｒ复合体（Ｂ¨ｏｔＣ）对呼吸节律的影响。结果表明：（１）吸气相早期短串电刺激Ｂ¨ｏｔＣ导致膈神经放电被短暂抑制，被抑制的程度与刺激强度呈正相关。当刺激落位在吸气相中、晚期时，可导致吸气提前终止（“吸气切断”），之后跟随一缩短的呼气相。导致“吸气切断”的阈强度与刺激落位呈负相关。（２）呼气相短串电刺激Ｂ¨ｏｔＣ，可诱导膈神经短暂放电，呼气相晚期诱导出现放电之后往往跟随一正常的吸气放电，结果导致该呼气相缩短。该效应亦具有刺激强度、刺激落位依赖性。结果提示：Ｂ¨ｏｔＣ参与吸气向呼气以及呼气向吸气的时相转换。     

刺激面神经核背内侧区及腹内侧区对颏舌肌和膈肌肌电活动的影响

在４４只氨基甲酸乙酯麻醉、断双侧迷走神经的健康成年家兔上、观察电、化学刺激面神经核背内侧区和腹内侧区对颏舌肌和膈肌肌电活动的影响。结果如下：（１）长串电脉冲刺激ｄＭＮＦ引起颏舌肌和膈肌肌电活动明显增强;（２）短串电脉冲刺激ｄＭＦＮ,当刺激落用于吸气相时,引起颏舌肌和膈肌在呼气相的肌是有终止;（３）长串电脉冲刺激ｖＭＮＦ使颏舌肌和膈肌肌电活动明显被抑制;（４）短中电脉冲刺激ｖＭＮＦ,当刺激落位有气相     

电及化学刺激兔面神经核腹内侧区对呼吸时相的影响

实验用家兔42只,乌拉坦静脉麻醉、三碘季铵酚麻痹、人工通气、断双侧颈迷走神经、引导膈神经传出电活动,观察电及化学刺激面神经核腹内侧区(VMNF区)对呼吸时相的影响。结果表明:(1)长串(6—8s)电脉冲刺激VMNF区,刺激强度达到相应阈值(100—15OμA,频率100c/s,波宽0.3ms)可完全抑制膈神经放电。(2)短串(0.1s)电脉冲刺激VMNF区,适当强度的刺激落位在吸气相中后期,可引起吸气切断(IO-S)效应;落位在呼气相中后期,可引起呼气切断(EO-S)效应。(3)此区微量注射细胞体兴奋剂L-谷氨酸钠后,呼吸频率减慢,膈神经放电积分幅度降低。结果提示:VMNF区可能是延髓呼吸中枢IO-S机制的重要结构之一,并参与呼吸时相转换控制的调节。     

电刺激兔延髓腹侧化学敏感区和压力敏感区对呼吸、血压,的影响及其中枢递质机制

电刺激麻醉兔延髓腹侧化学敏感区头端区引起潮气量(V_T)增加,呼吸频率(f)增快;电刺激压力敏感区(中间区)则使V_T减小,f亦增快。弱刺激时,两者均产生降压反应;刺激增强可诱发双相或升压反应。在出现周期性呼吸时,电刺激化学敏感区可使呼吸节律正常化、V_T增大,而电刺激压力敏感区则导致呼吸暂停。电刺激压力敏感区时,吸气时间(TI)和呼气时间(T_E)均缩短,以T_E变化更明显;由于V_T减小和T_I缩短,V_T/T_I保持相对不变,提示吸气终止的中枢阈值降低。在准备刺激的相应局部预先应用阿托品,可使电刺激化学敏感区产生的通气增强效应翻转,而对电刺激压力敏感区引起的通气抑制无明显影响;用印防己毒素则可选择性消除电刺激压力敏感区的通气抑制和降压效应。本工作表明延髓腹侧存在两个不同的中枢机制,其中化学敏感区产生的通气增强与胆碱能系统有关;压力敏感区产生的通气减弱效应与GABA系统有关。     

刺激兔面神经核背内侧区对孤束核腹外侧亚核呼吸相关神经元的影响

本工作在氨基甲酸乙酯麻醉、断双侧颈迷走神经、肌松、人工呼吸的家兔上,观察了长短串电脉冲刺激面神经核背内侧区(DMNF)对孤束核腹外侧亚核(VLNTS)呼吸相关神经元(RRU)的影响。实验结果:当电刺激 DMNF 时,吸气性神经元(64.4%)放电频率增加,放电时程延长,并以递增性吸气神经元被兴奋的数量最多。呼气性神经元(35%)表现为放电停止和放电频率减少,以递减性呼气神经元被抑制的数量最多。左右两侧 VLNTS 呼吸相关神经元对电刺激 DMNF 的反应无显著性差异,P>0.05。结果提示:DMNF 兴奋可以易化 VLNTS 吸气性神经元,抑制呼气性神经元。两者之间的功能及结构联系是一个值得注意的问题。     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

Enterovirus 71 3C proteolytically processes the histone H3 N-terminal tail during infection

Highlights
1. The N-terminal tail of histone H3 is specifically cleaved during EV71 infection.
2. Viral protease 3C is identified as a protease responsible for proteolytically processing the N-terminal H3 tail.
3. Our finding reveals a new epigenetic regulatory mechanism for Enterovirus 71 in virus-host interactions.     

Detection of EBV and HHV6 in the Brain Tissue of Patients with Rasmussen’s Encephalitis

Rasmussen’s encephalitis (RE) is a rare pediatric neurological disorder, and the exact etiology is not clear. Viral infection may be involved in the pathogenesis of RE, but conflicting results have reported. In this study, we evaluated the expression of both Epstein-Barr virus (EBV) and human herpes virus (HHV) 6 antigens in brain sections from 30 patients with RE and 16 control individuals by immunohistochemistry. In the RE group, EBV and HHV6 antigens were detected in 56.7% (17/30) and 50% (15/30) of individuals, respectively. In contrast, no detectable EBV and HHV6 antigen expression was found in brain tissues of the control group. The co-expression of EBV and HHV6 was detected in 20.0% (6/30) of individuals. In particular, a 4-year-old boy had a typical clinical course, including a medical history of viral encephalitis, intractable epilepsy, and hemispheric atrophy. The co-expression of EBV and HHV6 was detected in neurons and astrocytes in the brain tissue, accompanied by a high frequency of CD8⁺ T cells. Our results suggest that EBV and HHV6 infection and the activation of CD8⁺ T cells are involved in the pathogenesis of RE.     

Perinatal Vertical Transmission of Chikungunya Virus in Ruili,a Town on the Border between China and Myanmar

正Dear Editor,Chikungunya virus (CHIKV), an arbovirus in the family of Togaviridae, genus Alphavirus, is transmitted by the A.aegyptii or A. albopictus mosquito, and causes disease in humans characterized by fever, rash, and arthralgia (Silva and Dermody 2017; Suhrbier 2019). It was first reported in 1953 in Tanzania, and caused only a few outbreaks and sporadic cases in Africa and Asia in last century. However, in the epidemic in 2004, CHIKV acquired mutations that conferred enhanced transmission by the A. albopictus mosquito(Schuffenecker et al. 2006). Since then, it has successively caused outbreaks in Africa, the Indian Ocean, South East Asia, the South America, and Europe (Zeller et al. 2016).