术前焦虑,事出有因

临床上,医疗操作可能会引起病人的焦虑、恐惧反应,除了外科手术可能引起这些反应外,其他各科的诊断和治疗手术亦可能引起患者的种种不良反应,如内窥镜检查,牙科检查和治疗,以及某些特殊的医学程序,如分娩等。     

术前焦虑,事出有因

临床上,医疗操作可能会引起病人的焦虑、恐惧反应,除了外科手术可能引起这些反应外,其他各科的诊断和治疗手术亦可能引起患者的种种不良反应,如内窥镜检查,牙科检查和治疗,以及某些特殊的医学程序,如分娩等。     

与人类疾病有关的沙粒病毒研究进展

沙粒病毒为单股负链分节段的RNA病毒,迄今已知仅一个科一个属,分为旧世界沙粒病毒(Old World Arenavimses)和新世界沙粒病毒(New World Arenaviruses)两大类,有20余种血清型,其中大多数种类可引起人类严重疾病,如拉沙病毒(Lassa virus)引起拉沙热,胡宁病毒(Junin virus)引起阿根廷出血热,马秋博病毒(Machupo virus)和Chapare病毒引起玻利维亚出血热,瓜纳瑞托病毒(Guanarito virus)引起委内瑞拉出血热,沙比亚病毒(sabi(a) virus)引起巴西出血热,淋巴细胞脉络丛脑膜炎病毒(LCMV)引起淋巴细胞脉络丛脑膜炎.本文对沙粒病毒及其引起的主要疾病的研究进展作一综述.     

与人类疾病有关的沙粒病毒研究进展

沙粒病毒为单股负链分节段的RNA病毒,迄今已知仅一个科一个属,分为旧世界沙粒病毒(Old World Arenavimses)和新世界沙粒病毒(New World Arenaviruses)两大类,有20余种血清型,其中大多数种类可引起人类严重疾病,如拉沙病毒(Lassa virus)引起拉沙热,胡宁病毒(Junin virus)引起阿根廷出血热,马秋博病毒(Machupo virus)和Chapare病毒引起玻利维亚出血热,瓜纳瑞托病毒(Guanarito virus)引起委内瑞拉出血热,沙比亚病毒(sabi(a) virus)引起巴西出血热,淋巴细胞脉络丛脑膜炎病毒(LCMV)引起淋巴细胞脉络丛脑膜炎.本文对沙粒病毒及其引起的主要疾病的研究进展作一综述.     

与人类疾病有关的沙粒病毒研究进展

沙粒病毒为单股负链分节段的RNA病毒,迄今已知仅一个科一个属,分为旧世界沙粒病毒(Old World Arenavimses)和新世界沙粒病毒(New World Arenaviruses)两大类,有20余种血清型,其中大多数种类可引起人类严重疾病,如拉沙病毒(Lassa virus)引起拉沙热,胡宁病毒(Junin virus)引起阿根廷出血热,马秋博病毒(Machupo virus)和Chapare病毒引起玻利维亚出血热,瓜纳瑞托病毒(Guanarito virus)引起委内瑞拉出血热,沙比亚病毒(sabi(a) virus)引起巴西出血热,淋巴细胞脉络丛脑膜炎病毒(LCMV)引起淋巴细胞脉络丛脑膜炎.本文对沙粒病毒及其引起的主要疾病的研究进展作一综述.     

肺炎链球菌蛋白疫苗候选蛋白研究进展

肺炎链球菌能够引起肺炎、脑膜炎、中耳炎等疾病,在世界范围内具有很高的致病率和致死率。患者主要集中在婴幼儿、老年人和免疫力低下的人群。据统计,每年大约有一百万的五岁以下儿童死于肺炎链球菌引起的疾病。抗生素是肺炎链球菌引起疾病最常用的治疗药物,但是,耐青霉素和多重耐     

应激对海马形态和功能影响的研究进展

近年来 ,应激对机体的损伤 (神经系统、心血管系统、消化系统、免疫系统 )引起广泛的关注 ,并在应激对海马形态和功能的影响研究方面取得了进展。本文旨在对应激引起的海马树突损伤 ,海马神经元的脱落及其机制以及由此引起动物和人的认知功能的损伤进行综述。     

蒺藜有效成分治疗心脑血管性疾病的实验和临床研究

本文对蒺藜有效成分之一的JL-1进行了实验和临床研究。动物实验中,JL-1对由ADP引起的大鼠血小板聚集,由KCl引起的离体兔主动脉血管平滑肌收缩和大鼠体外血栓形成均有显著抑制作用,改善由高分子右旋糖酐引起的兔球结膜微循环障碍,显著降低正常大鼠和高血压大鼠TXB_2含量,对6-Keto-PGF_(Ia)无影响。临床研究中,JL-1对心脑血管病患者综合征疗效与Aspirin相似,显著降低血液流变学各项指标,显著降低甘油三脂与升高高密度脂蛋白,优于Aspirin。未发现因用药而引起的化验变化和严重副反应,     

硫化氢通过氧化还原抑制棕榈酸引起上皮细胞钠通道异常激活的机制研究

目的:探讨棕榈酸激活上皮细胞钠通道(epithelial sodium channel,ENa C)的分子机制,以及H_2S对抗棕榈酸引起的ENa C异常激活的作用和机制。方法:应用肾皮质集合管上皮细胞,采用膜片钳技术研究H_2S对抗棕榈酸引起ENa C异常激活的保护作用和分子机制;应用激光共聚焦显微镜技术观察棕榈酸能否调节细胞内钙水平和细胞内ROS水平变化。结果:棕榈酸引起的细胞ENa C活性升高可以被Na HS抑制;棕榈酸引起的细胞内ROS水平升高可以被Na HS抑制,且应用NADPH抑制剂APO可以抑制棕榈酸引起的ENa C活性升高;棕榈酸可以引起细胞内钙的升高;应用钙离子螯合剂BAPTA/AM或IP3受体抑制剂APB可以抑制棕榈酸引起的ENa C活性升高;胰岛素受体抑制剂HNMPA和PI3K抑制剂LY204002也可以抑制棕榈酸引起的ENa C活性升高;DTT可以模拟Na HS对棕榈酸引起ENa C异常激活的保护作用。结论:棕榈酸通过诱导胰岛素受体磷酸化,引起细胞内钙释放,进而激活NADPH升高细胞内活性氧水平,引起ENa C异常激活。气体信号分子H_2S通过氧化还原反应抑制棕榈酸引起的ENa C异常激活。     

甲型流感病毒与免疫

甲型流感病毒是引起大规模流感爆发的主要病原体,在流行期间引起超额死亡率。近年来,高致病性禽流感病毒（HSN1和H7N7）引发的疫情引起了全世界的广泛关注。对甲型流感病毒引起机体免疫系统的变化及免疫应答的发生深入了解,有助于了解甲型流感病毒的致病机制,以采取更有效的治疗措施、设计更有效的抗病毒药物和流感疫苗,有助于应对有可能到来的甲型流感爆发的威胁。本文就甲型流感病毒诱导机体免疫应答的研究进展进行综述。     

Cyclospora cayetanensis: review of an emerging intestinal pathogen

Cyclospora cayetanensis is an emerging pathogen. It is a new human coccidian agent of intestinal disease. Twenty years ago, the first known human cases of cyclosporiasis were reported in the medical literature. Cyclosporiasis occurs in persons of all ages and either in immunocompetent or immunocompromised hosts. The most characteristic feature of this infection is a syndrome of acute or chronic diarrhea. This parasite has a world-wide distribution. In previous reports, Cyclospora cayetanensis was associated with prolonged diarrhea in travellers, returning from developing countries. However, Cyclospora infection has recently been reported in non travellers in the United States and Canada. Cyclospora can be transmitted by ingestion of water or food contaminated with oocysts. The life cycle of Cyclospora cayetanensis is not fully known. Diagnosis of cyclosporiasis is made by direct examination of stool samples. To date, oral trimethoprim-sulfamethoxazole is the only effective treatment for Cyclospora infection.     

Uniform staining of Cyclospora oocysts in fecal smears by a modified safranin technique with microwave heating.

Cyclospora, a coccidian protist, is increasingly being identified as an important, newly emerging parasite that causes diarrhea, flatulence, fatigue, and abdominal pain leading to weight loss in immunocompetent persons with or without a recent travel history as well as in patients with AIDS. Modified Kinyoun's acid-fast stain is the most commonly used stain to identify the oocyst of this parasite in fecal smears. Oocysts of Cyclospora stain variably by the modified acid-fast procedure, resulting in the possible misidentification of this parasite. We examined fecal smears stained by six different procedures that included Giemsa, trichrome, chromotrope, Gram-chromotrope, acid-fast, and safranin stains. We report on safranin-based stain that uniformly stains oocysts of Cyclospora a brilliant reddish orange, provided that the fecal smears are heated in a microwave oven prior to staining. This staining procedure, besides being superior to acid-fast staining, is fast, reliable, and easy to perform in most clinical laboratories.     

Update on Cyclospora cayetanensis,a Food-Borne and Waterborne Parasite

Summary: The coccidian parasite Cyclospora cayetanensis is recognized as an emerging pathogen that causes protracted diarrhea in humans. The first cases of Cyclospora infection were reported in the late 1970s and were observed among expatriates and travelers in regions where infections are endemic. Since then, Cyclospora has been considered a cause of traveler''s diarrhea. Epidemiological investigations were reported and examined in areas of endemicity even before the true identity of Cyclospora was elucidated. Cyclospora was fully characterized in the early 1990s, but it was not until the 1995 Cyclospora outbreak in the United States and Canada that it caught the attention of the public and physicians. The biology, clinical presentation, epidemiology, diagnosis, treatment, and control of cyclosporiasis are reviewed, with a focus on diagnostic assays currently being used for clinical and environmental samples. Challenges and limitations in working with Cyclospora are also discussed.     

Importance of contact with soil in the transmission of cyclosporosis

Cyclospora cayetanensis is an emergent pathogen that causes endemic and epidemic diarrhea worldwide. The epidemiology of the infection is not well known. Transmission of the parasite occurs through an environmental vehicle. In industrialized countries, cyclosporosis has been most often associated with either food-borne outbreaks or traveller's diarrhea. In developing countries, infection has been linked with contaminated water or food, contact with animals or soils, and variables related with socioeconomic status. In a Venezuelan community, a strong correlation between environments conducive to fecal contamination and infection was observed, suggesting that direct contact with contaminated soil may be an important route of transmission in areas with substandard housing developments, and poverty a predisposing factor for cyclosporosis.     

A case of human cyclosporiasis causing traveler's diarrhea after visiting Indonesia

This is the first case of human cyclosporiasis reported in Korea. We detected the oocyst of Cyclospora cayetanensis from a 14-yr old girl who complained of persistent diarrhea after traveling to Indonesia. Round oocysts sized about 8 to 9 m with wrinkle on the wall were found in modified acid fast stained stool specimen. Stainability was variable from red to pale. Oocyst wall showed typical autofluorescence under ultraviolet illumination. The exact diagnosis for the cause of diarrhea and treatment for this patient were not provided at the right moment from the hospital since the diagnostic system for the Cyclospora infection was not ready in the clinical laboratory of the hospital. More attention should be paid on Cyclospora as a cause of diarrhea especially for those returning from a trip to the tropics and an adequate diagnostic system for the Cyclospora infection should be implemented in clinical laboratories as soon as possible.     

Epidemiology of Cyclospora cayetanensis and other intestinal parasites in a community in Haiti

We conducted an exploratory investigation in a community in Haiti to determine the prevalence of Cyclospora cayetanensis infection and to identify potential risk factors for C. cayetanensis infection. In 2001, two cross-sectional stool surveys and a nested case-control study were conducted. In 2002, a follow-up cross-sectional stool survey was conducted among children < or =10 years of age. Stool specimens from study participants and water samples from their wells were examined for Cyclospora and other intestinal parasites. In stools, the prevalence of infection with Cyclospora in persons of all ages decreased from 12% (20 of 167 persons) in February 2001 to 1.1% (4 of 352 persons) in April 2001, a 90.8% decrease. For children < or =10 years of age, the prevalence rates were 22.5% (16 of 71 children) in February 2001, 3.0% (4 of 135 children) in April 2001, and 2.5% (2 of 81 children) in January 2002. Use of the water from the artesian well in the northern region of the community versus the one in the south was the only risk factor associated with Cyclospora infection in multivariate analyses (odds ratio, 18.5; 95% confidence interval, 2.4 to 143.1). The water sample from one of the nine wells or water sources tested (one sample per source) in January 2001, shortly before the investigation began, was positive for Cyclospora by UV fluorescence microscopy and PCR. None of the water samples from the 46 wells or water sources tested during the investigation (one sample per source per testing period, including the artesian wells) were positive for Cyclospora. Further studies are needed to assess the role of water as a possible risk factor for Cyclospora infection in Haiti and other developing countries.     

Cyclospora cayetanensis presence in aquatic surroundings in Hanoi (Vietnam). Environmental study (well water, lakes and rivers)

Cyclospora cayetanensis is a pathogenic agent originating from the intertropical zone. It causes diarrhoeal diseases in local populations as well as in travellers visiting these zones. In the first part of this work, an epidemiological study on drinking water supply (reservoirs and consumers' taps) was conducted in Hanoi over 12 months; samples were daily collected and have revealed the presence of Cyclospora cayetanensis oocysts during the whole year in tanks and only during monsoon season. Molecular methods were used for species identification. In the second part, we tried to investigate different water sources in Hanoi city in order to detect Cyclospora cayetanensis environmental contamination: groundwaters, surface waters collected in lakes and rivers and also waters from treatment plants. Our results show that none Cyclospora cayetanensis oocyst was found in the groundwaters and in the desinfected finished waters after treatment. In contrast, in rivers and lakes samples, the level of positivity reached about 63.6% with significant differences between the districts regarding the rates of oocysts recovery: only 24% positive specimens in Hoan Kiem district, whilst respectively 80.4%, 78.3% and 65% positive samples in Hai Ba Trung, Dong Da and Ba Dinh districts. The results of this study seem to confirm that environmental water is contaminated by Cyclospora cayetanensis oocysts and points out the importance of water as a significant source of human transmission. It is quite obvious that observation could be probably extended to the other endemic areas.     

Prevalence of Cyclospora species and other enteric pathogens among children less than 5 years of age in Nepal.

Stools from 124 Nepalese children aged 6 to 60 months with diarrhea were examined for organisms of the coccidian genus Cyclospora and for other enteric pathogens. Enterotoxigenic Escherichia coli, Giardia Lamblia, Campylobacter species, Cyclospora species, and Cryptosporidium species were the most common pathogens identified. Cyclospora species were detected in none of 74 children < 18 months of age compared with 6 (12%) of 50 children > or = 18 months of age (P = 0.004).     

Detection of Cyclospora cayetanensis oocysts in human fecal specimens by flow cytometry

A diagnosis of cyclosporiasis typically involves stool examinations for the presence of Cyclospora oocysts by means of microscopy. In recent years, flow cytometry has been gaining in popularity as a novel method of detecting pathogens in environmental and clinical samples. The present study is an evaluation of a flow cytometric method for the detection and enumeration of Cyclospora oocysts in human fecal specimens associated with food-borne outbreaks of cyclosporiasis in Ontario, Canada. Flow cytometry results were generally very comparable to the original microscopy results for these specimens, in terms of both presence or absence of oocysts and relative oocyst concentrations. Of the 34 fecal specimens confirmed positive for Cyclospora by microscopy, 32 were also found positive by flow cytometry, and 2 others were considered equivocal. Of the eight fecal specimens reported to be negative by microscopy, two were found positive by flow cytometry and five others were considered equivocal. These two flow cytometry-positive samples and one of the equivocal samples were confirmed by microscopic reexamination, suggesting that flow cytometry may be more sensitive than microscopy. While the sample preparation time for flow cytometry is similar to or slightly longer than that for microscopy, the actual analysis time is much shorter. Further, because flow cytometry is largely automated, an analyst's levels of fatigue and expertise will not influence results. Flow cytometry appears to be a useful alternative to microscopy for the screening of large numbers of stool specimens for Cyclospora oocysts, such as in an outbreak situation.     

Cyclospora species as a gastrointestinal pathogen in immunocompetent hosts.

Previous reports of diarrhea resulting from Cyclospora species have been linked to travelers and immunocompromised patients. We conducted a prospective study of 1,042 formalin-ethyl acetate fecal concentrates collected from patients with diarrhea. Between May and November 1993, we identified three patients for whom studies were positive for nonrefractile spherical organisms measuring 10 microns in diameter and containing a cluster of refractile membrane-bound globules. The cysts exhibited variable acid fastness consistent with Cyclospora species. These three patients had no history of recent travel and presented with relapsing, watery, nonbloody diarrhea that lasted from 12 days to 8 weeks. No other parasitic or bacterial pathogens were identified in their stools. All three instances of diarrhea occurred in May or June. No common source of food or water was identified. None of these patients were immunosuppressed, and their diarrhea resolved spontaneously. We suggest that Cyclospora species should be considered in community-acquired diarrhea.