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。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

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.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.