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古老生命的时代从六亿到两亿多年前,在地球史上叫做古生代。古生代就是“古老生命的时代”的意思。从化石发现来看,生命到这个时代才相当繁荣起来。当然,古生代的生物已经相当复杂而多样了,这说明生物界已经经历了一段漫长的发展道路。不过,在古生代以前的生物,大多是海生浮游生物,身体大多是柔软组织,不容易保存成为化石。到了古生代,大多数生物过海底底栖生活了,身体里坚韧组织多了,保存成为化石的也就多起来了。动物界,各个门类的动物都出现了。特别是无脊椎动物的各个门类,有了很大的发展。植物界,除了被子植物门以外,其他门类的植物也都出现了。 相似文献
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中国动物学会无脊椎动物分类区系学术讨论会,1979年10月22—28日在浙江省杭州市举行。出席代表来自20个省市56个单位共89人。会议期间,新老科学家欢聚一堂,发扬学术民主,认真进行了学术讨论和经验交流,检阅了科研成果,讨论了共同关心的科研问题,了解了国内外研究的动态,分析了和与世界先进水平的差距,增强了赶超先进水平的信心。达到了预期的目的。 相似文献
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地质部、有关的大专院校和中国科学院三方面的11个单位,在过去的工作基础上,今年又在蓝田地区进行了大量考察和研究工作,井由中国科学院古脊椎动物与古人类研究所负责筹备举行了这次现场会议。现场会议是和全国第四纪第二次学术会议联合举行的,在第四纪学术会议之后,举行了现场会议。现场会议从11月3日下午起到8日止,共举行了5天半。会议广泛地讨论了蓝田新生界的问题,交流了工作经验,肯定了成绩,指出了缺点。会议开得很好,收获很大,基本上完成了大会所规定的任务 相似文献
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《小哥白尼(野生动物画报)》2016,(9)
正九头怪蛇相柳凶神恶煞,但其独特的多头造型却让猴子十分心动。于是,它们请大圣孙悟空施展法术,"添加"了好几个脑袋。这下,猴子的生活可精彩了。孙悟空变出了10个头后,饭量也增加了10倍。很快,花果山就变成了一片荒地,许多猴子都饿死了。猪八戒看见后,决定劫富济贫,结果还没来得及行动就被10个头的孙悟空吃了。聊城薛宸轩(等等,不是说好的孙悟空帮猴子们变化吗?它是不是,耳背听错了?) 相似文献
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远程教育培训给生物教学带来新的生机。夯实了专业知识,梳理了生物知识,使我认识到应该如何把握生物课堂教学,提高了课堂教学设计能力,凝聚了生物教师的力量,使老师们学到了很多知识和教学技能,解决了平时教学中的一些难题,提升了生物的教学水平。 相似文献
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HHV-8 sequences were recently identified in 100% of the amplifiable samples from AIDS patients with Kaposi's sarcoma(KS)and in 15% of the non-KS tissue samples from AIDS patients, so there is a strong correlation of Kaposi's sarcoma with HHV-8. Serum and DNA samples from a clinically diagnosed Kaposi's sarcoma Chinese patient were tested. HHV-8 antibody was tested positive by IFA and HIV-I antibody was negative by Western blot. The KS330 PCR product was found both in peripheral blood mononuclear cells and in KS tumor cells from this Chinese patient. This supports the hypothesis that Kaposi's sarcoma results from infection of HHV-8. 相似文献
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HIV-1进攻靶细胞的机制及相应环节抑制剂 总被引:2,自引:0,他引:2
HIV-1是导致获得性免疫缺陷综合症(AIDS)的流行最广、破坏力最强的病毒。HIV-1分两个步骤特异性地进攻CD4^ 细胞:一是利用表面糖蛋白gp120和靶细胞膜上的受体结合;二是通过跨膜糖蛋白gp41使病毒的包膜和靶细胞的质膜发生融合,经过上述步骤,病毒的核心蛋白和遗传物质得以进入人体,然其中进行复制,遇时,细胞膜的稳定性被破坏,细胞的内外环境失去平衡,最终导致细胞死亡。HIV-1进攻靶细胞的机制研究所取得的成就为研制安全有效的抗HIV/AIDS药物提供了新的思路和方向。 相似文献
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With a global commitment to scaling up AIDS care and treatment in resource‐poor settings for some of the most HIV‐affected countries in Africa, availability of antiretroviral treatment is no longer the principal obstacle to expanding access to treatment. A shortage of trained healthcare personnel to initiate treatment and manage patients represents a more challenging barrier to offering life‐saving treatment to all patients in need. Physician‐centered treatment policies accentuate this challenge. Despite evidence that task shifting for nurse‐centered AIDS patient care is effective and can alleviate severe physician shortages that currently obstruct treatment scale‐up, political commitment and policy action to support task shifting models of care has been slow to absent. In this paper we review the evidence in support of task shifting for AIDS treatment in Africa and argue that continued policy inaction amounts to unwarranted healthcare rationing and as such is ethically untenable. 相似文献
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P. Portegies J. de Gans J. M. Lange M. M. Derix H. Speelman M. Bakker S. A. Danner J. Goudsmit 《BMJ (Clinical research ed.)》1989,299(6703):819-821
OBJECTIVE--To assess the incidence of the AIDS dementia complex and the presence of HIV I p24 antigen in cerebrospinal fluid in relation to zidovudine treatment. DESIGN--Retrospective study of a consecutive series of patients with AIDS from 1982 to 1988. SETTING--An academic centre for AIDS. PATIENTS--196 Patients with AIDS and neurological symptoms examined from 1982 to 1988. INTERVENTIONS--Zidovudine treatment, which was introduced to The Netherlands on 1 May 1987 for patients with severe symptoms of HIV infection (Centers for Disease Control groups IVA, B, C, and D). MAIN OUTCOME MEASURES--Diagnosis of AIDS dementia complex and presence of HIV I p24 antigen in cerebrospinal fluid. RESULTS--The AIDS dementia complex was diagnosed in 40 of the 196 (20%) patients with AIDS. Thirty eight of 107 patients with AIDS (36%) not taking zidovudine developed the AIDS dementia complex compared with two of the 89 (2%) taking the drug (p less than 0.00001). The incidence of the AIDS dementia complex increased to 53% in the first half of 1987, after the introduction of zidovudine in May 1987, decreasing to 10% in the second half of 1987 and to 3% in 1988. Dementia was diagnosed before definition of the AIDS dementia complex (1986) according to DSM-III criteria and there was good agreement between diagnosis before and after 1986. Sixteen of 61 samples of cerebrospinal fluid (26%) from patients with AIDS (10 with the AIDS dementia complex) not taking zidovudine were positive for HIV I p24 antigen, whereas none of 37 cerebrospinal fluid samples from patients with AIDS (two with the AIDS dementia complex) taking zidovudine were positive. CONCLUSIONS--The incidence of AIDS dementia complex in patients with AIDS declined after the introduction of systematic treatment with zidovudine; the AIDS dementia complex might be prevented by inhibiting viral replication in the central nervous system. 相似文献
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In the last two years, we have seen a remarkable intensification in the response to AIDS in China. A number of organizations have joined and contributed to the efforts of the Chinese government in responding the AIDS epidemic in China. This article specifically describes the role of the United Nations in supporting and strengthening those responses.Achievements of the United Nations (UN) highlighted in the article include: strengthened leadership and political commitment to respond to AIDS; improved HIV/AIDS surveillance and information; expanded prevention efforts; improved treatment, care and support to people living with HIV and increased resources for AIDS programs. Additional roles of e., one national plan on AIDS; one national coordinating authority for AIDS; and one monitoring and evaluation system for AIDS. In addition, the UN system is expected to strengthen alignment and harmonization of activities of all international organizations and improved accountability and oversight. Remaining challenges identified include increasing awareness of AIDS and reducing stigma and discrimination; reducing vulnerability and risk behaviour among specific groups;providing improved treatment, care and support for people living with HIV; promoting stronger engagement by civil society, and; addressing the gender dimensions of AIDS. 相似文献
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王福春 《微生物学免疫学进展》2014,(5):52-56
目的了解广西靖西县1997—2012年HIV/AIDS流行病学状况,分析流行趋势,为制定艾滋病防治措施提供科学依据。方法采用描述流行病学分析方法,对靖西县1997—2012年艾滋病疫情监测资料进行分析。结果靖西县1997—2012年累计报告HIV/AIDS 147例,其中HIV感染者60例,AIDS病人47例,死亡40例;男性95例,女性52例,男女性别比为1.83∶1;以20~49岁青壮年为主,这些年龄组发病率为3.24/10万;传播途径以性接触传播为主,占90.48%;其次为静脉注射毒品传播,占6.80%。结论靖西县艾滋病流行近年呈明显上升趋势,艾滋病已经从高危人群向普通人群扩散传播,性接触传播已经成为艾滋病的主要传播途径,应加强对高危人群性行为的干预,遏制艾滋病传播蔓延。 相似文献
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In 1981 a new epidemic of about two-dozen heterogeneous diseases began to strike non-randomly growing numbers of male homosexuals and mostly male intravenous drug users in the US and Europe. Assuming immunodeficiency as the common denominator the US Centers for Disease Control (CDC) termed the epidemic, AIDS, for acquired immunodeficiency syndrome. From 1981-1984 leading researchers including those from the CDC proposed that recreational drug use was the cause of AIDS, because of exact correlations and of drug-specific diseases. However, in 1984 US government researchers proposed that a virus, now termed human immunodeficiency virus (HIV), is the cause of the non-random epidemics of the US and Europe but also of a new, sexually random epidemic in Africa. The virus-AIDS hypothesis was instantly accepted, but it is burdened with numerous paradoxes, none of which could be resolved by 2003: Why is there no HIV in most AIDS patients, only antibodies against it? Why would HIV take 10 years from infection to AIDS? Why is AIDS not self-limiting via antiviral immunity? Why is there no vaccine against AIDS? Why is AIDS in the US and Europe not random like other viral epidemics? Why did AIDS not rise and then decline exponentially owing to antiviral immunity like all other viral epidemics? Why is AIDS not contagious? Why would only HIV carriers get AIDS who use either recreational or anti-HIV drugs or are subject to malnutrition? Why is the mortality of HIV-antibody-positives treated with anti-HIV drugs 7–9%, but that of all (mostly untreated) HIV-positives globally is only 1–4%? Here we propose that AIDS is a collection of chemical epidemics, caused by recreational drugs, anti-HIV drugs, and malnutrition. According to this hypothesis AIDS is not contagious, not immunogenic, not treatable by vaccines or antiviral drugs, and HIV is just a passenger virus. The hypothesis explains why AIDS epidemics strike non-randomly if caused by drugs and randomly if caused by malnutrition, why they manifest in drug- and malnutrition-specific diseases, and why they are not self-limiting via anti-viral immunity. The hypothesis predicts AIDS prevention by adequate nutrition and abstaining from drugs, and even cures by treating AIDS diseases with proven medications. 相似文献
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S. C. Darby C. R. Rizza R. Doll R. J. Spooner I. M. Stratton B. Thakrar 《BMJ (Clinical research ed.)》1989,298(6680):1064
OBJECTIVE--To estimate the cumulative incidence of AIDS by time since seroconversion in haemophiliacs positive for HIV and to examine the evidence for excess mortality associated with HIV in those who had not yet been diagnosed as having AIDS. DESIGN--Analysis of data from ongoing national surveys. SETTING--Haemophilia centres in the United Kingdom. PATIENTS--A total of 1201 men with haemophilia who had lived in the United Kingdom during 1980-7 and were positive for HIV. INTERVENTION--None. END POINTS--Diagnosis of AIDS; death in those not diagnosed as having AIDS. MEASUREMENTS AND MAIN RESULTS--Estimation of cumulative incidence of AIDS and number of excess deaths in seropositive patients not diagnosed with AIDS. Median follow up after seroconversion was 5 years 2 months. Eight five patients developed AIDS. Cumulative incidence of AIDS five years after seroconversion was 4% among patients aged less than 25 at first test positive for HIV, 6% among those aged 25-44, and 19% among those aged greater than or equal to 45. There was little evidence that type or severity of haemophilia or type of factor VIII or IX that had caused HIV infection affected the rate of progression to AIDS. Mortality was increased among those who had not been diagnosed as having AIDS, especially among those with "AIDS related complex." Thirteen deaths were observed among 36 patients diagnosed as having AIDS related complex against 0.65 expected, and 34 deaths in 1080 other patients against 22.77 expected; both calculations were based on mortality rates observed in haemophiliacs in the United Kingdom in the late 1970s. CONCLUSIONS--Rate of progression to AIDS depended strongly on age. There is a substantial burden of fatal disease among patients positive for HIV who have not been formally diagnosed as having AIDS. 相似文献
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