青蒿素伍用周效磺胺乙胺嘧啶延缓伯氏鼠疟原虫抗药性的作用

以伯疟原虫(P.berghei K173)一小白鼠体内试验系统,研究青蒿素与周效磺胺—乙胺嘧啶的合理组方及其抗药性的作用。实验结果表明,青蒿素伍用周效磺胺—乙胺嘧啶(2:1)的最佳配比为20:0.05,三药伍用药效学呈相加型协同作用,其增效指数SD_(50)为7.3,SD__(90)为6.9。复方对鼠疟的治疗作用早期效果明显优于单药,但后期原虫转阴率及动物平均死亡时间与周效磺胺—乙胺嘧啶相似。复方抗性系的耐药剂量及抗性指数显著低于单药,提示复方对鼠疟有明显的延缓抗药性的作用,可能成为具有高效、速效及延缓抗药性作用的抗疟复方。     

复方萘酚喹治疗间日疟的疗效观察

目的 :观察复方萘酚喹与氯喹治疗间日疟的临床疗效。方法 :以显微镜血检单纯间日疟原虫阳性患者为观察对象 ,药物为复方萘酚喹 (萘酚喹 40 0mg 青蒿素 1 0 0 0mg) ,1次顿服 ,服药后按时测量体温和血检原虫 ,随访 42天 ,观察治疗效果。结果 :复方萘酚喹治疗 1 0 9例 ,平均退热时间为 ( 1 3 0± 5 5 )h ,原虫转阴时间为 ( 1 8 1± 5 7)h,治愈率为 1 0 0 %。药后无明显不良反应。结论 :复方萘酚喹治疗间日疟具有良好的效果。     

复方磷酸萘酚喹片治疗疟疾95例的临床观察

1998～1999年在海南保显、吊罗山医院用军事医学院科学院五所提供的复方磷酸萘酚喹片(含萘酚喹和青蒿素)治疗恶性疟55例,间日疟40例,取得良好的即时疗效和较好的近期效果。平均退热时间分别为22.00±8.89小时和15.33±4.55小时,平均原虫无性体转阴时间分别为23.39±7.02小时和14.00±5.05小时,平均24小时原虫下降率分别为98.21％     

磷酸萘酚喹治疗恶性疟的疗效初步观察

目的 :观察磷酸萘酚喹与氯喹治疗恶性疟的临床疗效。方法 :以显微镜血检单纯恶性疟原虫阳性患者为观察对象 ,药物为磷酸萘酚喹 ,成人总量 10 0 0mg ,首次 6 0 0mg ,2 4h服 4 0 0mg ,服药后按时测量体温和血检原虫 ,随访 2 8天 ,观察治疗效果。结果 :磷酸萘酚喹治疗 4 0例 ,平均退热时间为 (35 9± 16 7)h ,原虫转阴时间为 (6 1 7± 18 1)h ,治愈率为 10 0 %。药后无明显不良反应。结论 :磷酸萘酚喹治疗恶性疟疾具有良好的效果。     

复方磷酸萘酚喹及其组分单药治疗恶性疟的临床研究

为了对比观察复方萘酚喹(Co NQ)与组分单药磷酸萘酚喹(NQ)和青蒿素(QHS)对恶性疟的疗效和安全性,本研究用Co -NQ (总量含NQ 4 0 0mg及QHS10 0mg)、NQ (总量10 0 0mg)和QHS (总量2 5 0 0mg)分别治疗恶性疟患者30例。所有患者住院7天,随访2 8天,观察疗效和安全性。结果显示Co NQ、NQ和QHS 3组的平均退热时间分别为2 0 1±11 .8h、2 4 . 4±16. 1h和18 .0±9. 3h ;平均原虫转阴时间分别为30 . 1±5 . 7h、4 4 7±9 .2h和2 8 .9±5 . 6h ;2 8天治愈率分别为10 0 %、10 0 %和6 3 .3%。提示复方萘酚喹治疗恶性疟具有良好的临床效果。     

青蒿化学成份及其与青蒿素伍用对鼠疟的药效学研究

实验采用鼠疟模型及Peters4天抑制试验法,对从青蒿中分离得到的主要化学成份及其与青蒿素伍用进行了药效学评价。结果显示,青蒿素（QHS）的ED50和ED90分别为（10.2±1.3）mg/kg/d和（29.0±2.7）mg/kg/d。将青蒿素、青蒿酸、青蒿乙素、东莨菪内酯按1∶1∶1∶1混合得到QHH,其ED50和ED90分别为（12.6±1.1）mg/kg/d和（47.0±5.7）mg/kg/d。青蒿酸（QHA）、青蒿乙素（QHB）、东莨菪内酯（QHC）、青蒿黄酮1（QHD）、青蒿黄酮2（QHE）5种成份对鼠疟均有不同程度的抑制作用,但剂量高达500mg/kg/d时,抑制率最高也仅达到59%,远低于QHS的疗效。将分离的5种成份分别与QHS的半数有效剂量配伍进行药效测定,仅QHC的高剂量组显示一定的协同作用,其他各个组均未显示增效。QHH中QHS仅占1/4,但对鼠疟药效测定的结果ED50和ED90的值与QHS相近,提示QHA、QHB、QHC混合成份对QHS有一定的协同作用。因此,传统中药青蒿对疟疾的疗效是由以青蒿素为主的多组份共同作用的结果。     

不同种鼠对实验脑型疟发生的影响研究

目的比较昆明小鼠和C57BL/6小鼠作为种鼠对实验脑型疟模型的影响。方法分别以伯氏疟原虫ANKA株感染C57BL/6小鼠和昆明小鼠作为传代用种鼠,当种鼠原虫率为5%～15%时接种子代C57BL/6小鼠,观察两组小鼠原虫率、脑型疟发生率以及死亡率。同时,通过脑组织切片和脑部淋巴细胞的流式检测,观察两组发生脑型疟小鼠的脑部微血管中感染疟原虫红细胞和CD8＋T细胞的粘附情况,另外,通过感染CD8＋TKO小鼠,证实CD8＋T细胞在两组小鼠发生脑型疟中的作用。结果用昆明小鼠作为种鼠的实验组的原虫率和脑型疟发生率均明显高于用C57BL/6小鼠作为种鼠的实验组,发生脑型疟小鼠的脑部组织切片发现,脑部微血管可见明显的感染疟原虫红细胞的粘附和CD8＋T淋巴细胞浸润;而用昆明小鼠作为种鼠感染CD8＋T细胞缺失的C57BL/6小鼠并不能诱导实验脑型疟的发生。结论与C57BL/6小鼠相比,昆明小鼠作为种鼠的实验组的脑型疟发病率更高,而且感染疟原虫红细胞和CD8＋T细胞在脑部微血管内的粘附也是该脑型疟发生的主要因素,因此,更适合用于实验脑型疟模型的建立及其机制的探讨。     

咯萘啶、磺胺多辛与乙胺嘧啶不同配伍治疗恶性疟的比较研究

咯荼啶(咯)/磺胺多辛(磺)/乙胺嘧啶(乙)伍用时,明显延缓伯氏疟原虫对咯或三药产生抗性,不增加咯的毒性。为探讨三药伍用的合理剂量方案,1986～1990年,在海南省多重抗药性恶性疟流行区,先后伍用咯/磺/乙4种不同剂量,治疗观察恶性疟274例,结果如下: (1)咯500/磺1009/乙50mg顿服,治疗142例,平均退热时间30.1±15.1～46.3±     

恶性疟原虫裂殖子表面蛋白1羧基端编码基因真核表达重组克隆的构建

目的构建以恶性疟原虫红内期重要的疫苗候选抗原——裂殖子表面蛋白１（ＭＳＰ１）羧基端编码分子量４２０００蛋白的基因片段为外源基因的可用作候选核酸疫苗的真核表达载体。方法目前对疟疾核酸疫苗的研究仅见于鼠疟，将恶性疟原虫ＦＵＰ株裂殖子表面蛋白１羧基端编码４２０００蛋白的基因片段用常规分子克隆方法，分别克隆入非分泌性真核表达载体ＶＲ１０１２和改建后的分泌型载体ＶＲ１０１２／ＴＰＡ中，通过ＰＣＲ和酶切鉴定出重组克隆。结果成功地构建了真核表达载体ＶＲ１０１２／ＭＳＰ１－４２和ＶＲ１０１２／ＴＰＡ／ＭＳＰ１－４２。结论目前对疟疾核酸疫苗的研究仅见于鼠疟红外期，该研究对研制有效的恶性疟原虫红内期核酸疫苗是一个有益的尝试。其免疫保护作用待进一步研究。     

调节性T细胞修饰前炎症应答对小鼠脑型疟疾发生的影响

为探讨调节性T细胞（Tregs）对伯氏疟原虫感染所致鼠脑型疟发生和感染结局的影响机制,用伯氏疟原虫ANKA株分别感染对照组和抗CD25单克隆抗体注射组C57BL／6小鼠,计数红细胞感染率;感染前和感染后3、5、8天制备脾细胞悬液,流式细胞术检测脾Tregs百分含量;ELISA和Griess方法检测脾细胞培养上清IFN-γ、IL-10和NO水平。结果表明大多数C57BL／6鼠于感染后8—11天死于脑疟,抗CD25单克隆抗体注射组小鼠感染后3～4周死于贫血和过度原虫血症。对照组小鼠脾细胞培养上清IFN-γ、NO、IL—10水平于感染后开始升高,感染后5天达到峰值,感染后8天与感染后5天相比,IFN-γ、NO轻微下降,IL-10显著下降。感染后3、5天,实验组IFN-γ、NO水平显著高于对照组,IL—10水平显著低于对照组。感染后8天,实验组和对照组IFN-γ、NO、IL-10水平得到逆转。这表明Tregs通过修饰前炎症应答影响伯氏疟原虫感染鼠脑型疟发生和感染结局。     

Selection and reversal of<Emphasis Type="Italic"> Plasmodium berghei</Emphasis> resistance in the mouse model following repeated high doses of artemether

Artemether, a derivative of artemisinin, is effectively used for the treatment of malaria without any clinically relevant resistance to date. Artemether has also been developed as an antischistosomal agent, exhibiting highest activity against immature parasites. Here, we employ a rodent model and investigate whether the proposed artemether treatment schedule to prevent schistosome-attributable morbidity might select for Plasmodium berghei resistance. Mice infected with an ANKA strain of P. berghei were treated with artemether at either 47 mg/kg or 300 mg/kg. Once every 7–10 days, parasitized erythrocytes were passed to the next group of mice, receiving the same doses of artemether, for 50 passages. Resistance development was slow but increased considerably over the final ten passages. At the higher dose of artemether, the indices of resistance were 4.8 and 8.8 after 40 and 50 passages, respectively. Importantly, resistance was unstable, since sensitivity reverted to near-normal after five passages without drug pressure. A moderate index of P. berghei resistance and no apparent reversibility was found in comparative experiments employing pyronaridine. In conclusion, the pace of resistance development in P. berghei to repeated high doses of artemether is slow and reversible.     

Glucan-enhanced immunogenicity of killed erythrocyte stages of Plasmodium berghei.

Intravenous injections of glucan simultaneously with Formalin-killed erythrocytic stages of Plasmodium berghei elicited a greater degree of resistance in mice against subsequent infection with viable parasites than injections of killed erythrocytic stages alone. In two experiments with P. berghei strain NK 65, 100% of mice immunized with the glucan-dead parasite preparation survived challenge, whereas only 28.6% of mice receiving dead parasites alone survived. In the third experiment, using P. berghei strain NYU-2, the same proportion of mice survived after immunization with glucan and dead parasites as with dead parasites alone (i.e., 10 of 11 in each group), but mice immunized with the glucan-dead parasite preparation experienced parasitemias of significantly less intensity and shorter duration than mice which received only dead parasites before infection. Inoculation of glucan alone or with normal erythrocytes conferred no protection against challenge.     

Host defenses in murine malaria: induction of a protracted state of immunity with a formalin-killed Plasmodium berghei blood parasite vaccine.

Random-bred mice were immunized with a nonliving antigen prepared from mixed-blood forms of Plasmodium berghei, strain NYU-2, in combination with Corynebacterium parvum and/or living BCG. A high proportion of intravenously immunized mice survived virulent challenge, but subcutaneous vaccination was less effective. Vaccinated mice developed a patent infection after challenge similar to that observed in normal controls. However, between days 12 to 20 postchallenge, infections in some vaccinated mice became subpatent, whereas infections in all normal controls progressed until death. The incidence of recrudescent infection was low and, eventually, a state of sterile immunity was established. The capacity of vaccinated mice to withstand P. berghei challenge was sustained at a fairly stable level for the 6-month period of observation. Mice that had survived a primary infection with P. berghei almost completely suppressed a second and larger challenge with the same organism.     

Gamma interferon production is critical for protective immunity to infection with blood-stage Plasmodium berghei XAT but neither NO production nor NK cell activation is critical

We have examined the roles of gamma interferon (IFN-gamma), nitric oxide (NO), and natural killer (NK) cells in the host resistance to infection with the blood-stage malarial parasite Plasmodium berghei XAT, an irradiation-induced attenuated variant of the lethal strain P. berghei NK65. Although the infection with P. berghei XAT enhanced NK cell lytic activity of splenocytes, depletion of NK1.1(+) cells caused by the treatment of mice with anti-NK1.1 antibody affected neither parasitemia nor IFN-gamma production by their splenocytes. The P. berghei XAT infection induced a large amount of NO production by splenocytes during the first peak of parasitemia, while P. berghei NK65 infection induced a small amount. Unexpectedly, however, mice deficient in inducible nitric oxide synthase (iNOS-/-) cleared P. berghei XAT after two peaks of parasitemia were observed, as occurred for wild-type control mice. Although the infected iNOS-/- mouse splenocytes did not produce a detectable level of NO, they produced an amount of IFN-gamma comparable to that produced by wild-type control mouse splenocytes, and treatment of these mice with neutralizing anti-IFN-gamma antibody led to the progression of parasitemia and fatal outcome. CD4(-/-) mice infected with P. berghei XAT could not clear the parasite, and all these mice died with apparently reduced IFN-gamma production. Furthermore, treatment with carrageenan increased the susceptibility of mice to P. berghei XAT infection. These results suggest that neither NO production nor NK cell activation is critical for the resistance to P. berghei XAT infection and that IFN-gamma plays an important role in the elimination of malarial parasites, possibly by the enhancement of phagocytic activity of macrophages.     

Deletion of T cells bearing the V beta8.1 T-cell receptor following mouse mammary tumor virus 7 integration confers resistance to murine cerebral malaria

Plasmodium berghei ANKA induces a fatal neurological syndrome known as cerebral malaria (CM) in susceptible mice. Host genetic elements are among the key factors determining susceptibility or resistance to CM. Analysis of mice of the same H-2 haplotype revealed that mouse mammary tumor virus 7 (MTV-7) integration into chromosome 1 is one of the key factors associated with resistance to neurological disease during P. berghei ANKA infection. We investigated this phenomenon by infecting a series of recombinant inbred mice (CXD2), derived from BALB/c (susceptible to CM) and DBA/2 (resistant to CM) mice, with P. berghei ANKA. We observed differences in susceptibility to CM induced by this Plasmodium strain. Mice with the MTV-7 sequence in their genome were resistant to CM, whereas those without integration of this gene were susceptible. Thus, an integrated proviral open reading frame or similar genomic sequences may confer protection against neuropathogenesis during malaria, at least in mice.     

Host defenses in murine malaria: nonspecific resistance to Plasmodium berghei generated in response to Mycobacterium bovis infection or Corynebacterium parvum stimulation.

Infection with Mycobacterium bovis (BCG) or injection of killed Corynebacterium parvum protected some strain B6D2 F1 (C57BL/6xDBA/2) mice but did not protect strain ICR or A mice from lethal challenge with Plasmodium berghei strain NYU-2. B6D2 mice were not protected against challenges delivered immediately after intravenous injection of these materials, but rather protection developed by day 7 and persisted through at least day 84. Infections in protected mice progressed to about 10% parasitemia in parallel with infections initiated with the same inoculum in untreated controls. However, infections in most of the protected mice were cleared subsequently, whereas infections in untreated controls were uniformly fatal. A small number of treated mice developed protracted high-level erythrocytic infections, which led to markedly delayed death. BCG-infected mice which survived P. berghei infections had a factor in their sera which protected passively immunized recipients from P. berghei. BCG-infected mice passively immunized with protective serum controlled P. berghei infections better than normal mice given the same amount of the same serum and challenged with the same P. berghei inoculum. The capacity of BCG-infected B6D2 mice to resist P. berghei infection was not directly related to the pattern of growth of BCG, to the degree of splenomegaly, or to the level of activation of macrophages (measured as microbicidal capacity) caused by BCG infection. Therefore, I concluded that (i) BCG infection or injection of killed C. parvum altered the immunological potential of B6D2 mice in such a way as to allow the production of measurable levels of a protective humoral factor in response to infection with P. berghei; (ii) BCG infection caused the generation of a capacity which, when expressed in the presence of immune serum, provided an anti-P. berghei capacity which was superior to that provided by BCG infection alone or immune serum in the absence of BCG infection; and (iii) not all strains of mice could be protected from P. berghei by BCG or C. parvum injection.     

Fighting drug-resistant Plasmodium falciparum: the challenge of artemisinin resistance

Following a decade-long scale up of malaria control through vector control interventions, the introduction of rapid diagnostic tests and highly efficacious Artemisinin-based Combination Therapy (ACT) along with other measures, global malaria incidence declined significantly. The recent development of artemisinin resistance on the Cambodia-Thailand border, however, is of great concern. This review encompasses the background of artemisinin resistance in Plasmodium falciparum, its situation, especially in the Greater Mekong Sub-region (GMS), and the responses taken to overcome this resistance. The difficulties in defining resistance are presented, particularly the necessity of measuring the clinical response to artemisinins using the slow parasite-clearance phenotype. Efforts to understand the molecular basis of artemisinin resistance and the search for molecular markers are reviewed. The markers, once identified, can be applied as an efficient tool for resistance surveillance. Despite the limitation of current surveillance methods, it is important to continue vigilance for artemisinin resistance. The therapeutic efficacy “in vivo study'’ network for monitoring antimalarial resistance in the GMS has been strengthened. GMS countries are working together in response to artemisinin resistance and aim to eliminate all P. falciparum parasites. These efforts are crucial since a resurgence of malaria due to drug and/or insecticide resistance, program cuts, lack of political support and donor fatigue could set back malaria control success in the sub-region and threaten malaria control and elimination if resistance spreads to other regions.     

精制厌氧棒状杆菌细胞壁的佐剂作用及其对巨噬细胞的激活性能

本文主要观察经冷冻高压破碎菌体、SDS处理以及蛋白酶消化提纯的精制厌氧棒菌细胞壁的佐剂作用;用溶血空斑法测定抗体形成细胞数以及间接血凝法测定免疫小鼠血清抗体,证明其对抗原SRBC及BSA具有明显佐剂作用;此外亦能恢复带瘤小鼠(艾氏腹水癌)的吞噬功能。     

青嵩素和去氧青嵩素对小鼠淋巴细胞活化的抑制作用

一次急性大剂量青蒿素(500mg/kg)腹腔注射小鼠后,其血清对正常异体脾细胞经ConA 活化的~ 3H-UR 掺入有抑制作用。8小时的血清青蒿素浓度已降低,并不影响抑制,表明其在体内的代谢产物也参与了抑制作用。本文首次证明了去氧青蒿素对 ConA 活化的脾淋巴细胞的~H-UR 掺入有抑制作用。青蒿素和代谢产物的共同作用,导致了活化的淋巴细胞上述抑制作用。     

Calcium channel antagonist (nifedipine) attenuates Plasmodium berghei-specific T cell immune responses in Balb/C mice

Nifedipine and verapamil (Martin et al. Science 1987;235:899-901) are a class of calcium channel blockers involved in the reversal of chloroquine (CQ) drug resistance in CQ-sensitive Plasmodium spp. Nifedipine alters calcium-dependent functions of macrophages and neutrophils during Plasmodium berghei malaria. However, knowledge of nifedipine-induced immunomodulation of T cell functions during P. berghei malaria is still limited. We investigated the effect of nifedipine on the immune status of splenic T cells during P. berghei malaria. The intracellular calcium levels were determined in the FURA-2A/M loaded T cells by spectrofluorometry. Splenic T cell proliferation, phosphatidylserine (PS) externalization, Fas expression and Bcl2/Bax expression were determined by flow cytometry. We report a significant increase in mean percent parasitemia in nifedipine-treated and P. berghei-infected mice. Although nifedipine treatment alone did not affect the resting state free calcium levels in splenic T cells, the rise in intracellular calcium levels of T cells following P. berghei infection was significantly less in nifedipine-treated mice compared to untreated groups at various parasitemia levels. Antigen-specific splenic T cell proliferation and apoptosis was ablated in nifedipine-treated and untreated groups at various parasitemia levels. The study unequivocally reflects the suppression of P. berghei-specific T cell immune responses by nifedipine.