白色念珠菌诱导小鼠胸腺细胞凋亡

目的　研究白色念珠菌（ 白念菌） 在体内对小鼠胸腺细胞凋亡的诱导作用。方法　小鼠经尾静脉注射白念菌后,以流式细胞仪（ＦＣＭ） 分析、ＤＮＡ 琼脂糖凝胶电泳分析及细胞形态学改变为指标检测细胞凋亡。静脉注射ＮＯＳ 抑制剂观察对白念菌诱导胸腺细胞凋亡的影响。结果　白念菌能诱导小鼠胸腺细胞产生特征性的细胞凋亡形态学改变;流式细胞仪分析显示特征性的凋亡峰;琼脂糖凝胶电泳显示胸腺细胞出现典型的ＤＮＡ“梯状带”;用荧光染色（ＡＯ＋ ＥＢ） 以及ＦＣＭ 检测凋亡细胞百分率,发现白念菌注射后２４ 小时,胸腺细胞凋亡百分率随白念菌剂量增加而增高;用４ ×１０６ 白念菌经尾静脉注射后,胸腺细胞凋亡百分率于６ 小时开始增高,２４ 小时达高峰,以后迅速降低;小鼠胸腺萎缩,胸腺重量于１２ 小时明显降低,且于７２ 小时达到最低水平;ＮＯＳ 抑制剂氨基胍仅能部分抑制白念菌诱导的小鼠胸腺细胞凋亡;热灭活的白念菌不能诱导胸腺细胞凋亡。结论　白念菌菌血症能诱导小鼠胸腺细胞凋亡,而且呈时间和剂量依赖性;白念菌诱导小鼠胸腺细胞凋亡有赖于真菌的代谢;白念菌诱导小鼠胸腺细胞凋亡的过程可能与ＮＯ 部分相关。     

早期肠内肠外营养支持对结直肠癌患者术后影响

目的比较不同营养支持途径对结直肠癌患者术后营养指标的影响。方法回顾性分析自2010年1月至2014年1月84例胃癌和结直肠癌根治术后患者的临床资料,其中肠内营养组(EN组)43例和肠外营养组(PN组)41例,分别于术后第1天开始进行肠内和肠外营养,2组患者基本等氮、等热量;每组患者手术前后和术后第7天检测血清白蛋白(ALB)、转铁蛋白(TF)、前白蛋白(PA),观察术后不良反应、胃肠道功能恢复时间、感染、营养支持费用等情况。结果术后EN组和PN组的营养指标和不良反应发生率比较无显著性差异(P0.05);EN组感染发生率低(P0.01)且胃肠道功能恢复时间早(P0.01),与PN组相比较差异具有统计学意义。结论结直肠癌患者术后采用肠内营养方案,不良反应少、胃肠道功能恢复快。     

Detection of phospholipase activity of Candida albicans and non albicans isolated from women of reproductive age with vulvovaginal candidiasis in rural area

Background: Vulvovaginal candidiasis (VVC) is most common accounting for 17 to 39% of symptomatic women. Both Candida albicans and non albicans Candida species are involved in VVC. Amongst various virulence factors proposed for Candida, extracellular phospholipases is one of the virulence factor implicated in its pathogenicity. With this background the present study was carried out to find the prevalence of different Candida species and to detect phospholipase producing strains isolated from symptomatic women with VVC. Materials and Methods: At least two vaginal swabs from 156 women of reproductive age with abnormal vaginal discharge were collected. Direct microscopy and Gram’s stained smear examined for presence of budding yeast and pseudo mycelia followed by isolation and identification of Candida species. Extracellular phospholipase activity was studied by inoculating all isolates on Sabouraud’s dextrose egg yolk agar (SDA) medium. Results: Of the 156 women with curdy white discharge alone or in combination with other signs, 59 (37.82%) women showed laboratory evidence of VVC. A total of 31 (52.54%) women had curdy white discharge followed by 12 (20.33%) with other signs and symptoms. C. albicans (62.59%) and non albicans Candida (37.28%) in a ratio of 1.68:1 were isolated. Of the 37 strains of C. albians 30 (81.08%) showed the enzyme activity. Seventeen (56.66%) strains showed higher Pz value of < 0.70 (++++). Conclusion: Although there may be typical clinical presentation of Candidiasis. all the patients did not show laboratory evidence of infection. Pregnancy was found to be major risk factor for development of VVC. C. albicans was prevalent species but non albicans species were also frequently isolated. Extracellular phospholipase activity was seen in C. albicans and not in non albicans Candida isolates.     

IL‐17 plays a central role in initiating experimental Candida albicans infection in mouse corneas

The pathogenesis of fungal infection in the cornea remains largely unclear. To understand how the immune system influences the progression of fungal infection in corneas, we inoculated immunocompetent BALB/c mice, neutrophil‐ or CD4⁺ T‐cell‐depleted BALB/c mice, and nude mice with Candida albicans. We found that only immunocompetent BALB/c mice developed typical Candida keratitis (CaK), while the other mouse strains lacked obvious clinical manifestations. Furthermore, CaK development was blocked in immunocompetent mice treated with anti‐IL‐17A or anti‐IL‐23p19 to neutralize IL‐17 activity. However, no significant effects were observed when Treg cells, γδ T cells, or IFN‐γ were immunodepleted. Upon infection, the corneas of BALB/c mice were infiltrated with IL‐17‐producing leukocytes, including neutrophils and, to a lesser degree, CD4⁺ T cells. In contrast, leukocyte recruitment to corneas was significantly diminished in nude mice. Indeed, nude mice produced much less chemokines (e.g. CXCL1, CXCL2, CXCL10, CXCL12, CCL2, and IL‐6) in response to inoculation. Remarkably, addition of CXCL2 during inoculation restored CaK induction in nude mice. In contrast to its therapeutic effect on CaK, neutralization of IL‐17 exacerbated Candida‐induced dermatitis in skin. We conclude that IL‐17, mainly produced by neutrophils and CD4⁺ T cells in the corneas, is essential in the pathogenesis of CaK.     

Enhanced IgE response to Candida albicans in postoperative invasive candidiasis

Background Invasive candidiasis is a life-threatening complication problem in postoperative and immunocompromized patients, e.g. those treated by intensive care. Candida is frequently cultured from the mucous membranes of hospital patients and fungal cultures offer httle diagnostic help. Other diagnostic methods, such as blood cultures, serology and diagnostic imaging techniques produce results too late and, if positive, low sensitivity. Objective To study the value of Candida-specific antibodies, especially those of IgE class, in diagnosing invasive Candida infection. Methods The immunoglobulins IgE, IgG and IgM responses to antigens of Candida albicans in the sera of 14 patients with culture, biopsy and/or autopsy proven postoperative invasive candidiasis and of 11 colonized and 19 non-colonized operated patients were studied by mannan radioallergosorbent test (RAST), mannan enzyme-linked immunosorbent assay (ELISA) and immunoblotting. Results Detection of IgE antibodies to C. albicans polysaccharide (mannan) and protein antigens proved specific and sensitive in diagnostics of invasive candidiasis after major abdominal surgery. IgE rose early in the course of the infection and the method made a clear distinction between invasive infection and mucous colonization. Immunoblotting for protein antibodies was most sensitive while nitrocellulose-RAST for mannan antibodies was most specific. The combined use of immunoblotting and RAST increased the sensitivity and the specificity. Determinations of anti-Candida IgG and IgM antibodies had low sensitivity and specificity. Conclusion Critically ill patients with invasive candidiasis develop IgE antibodies to Candida antigens probably because of disturbed TH₁/TH₂ responses. Determination of specific IgE antibodies can be used as a diagnostic aid in the early stage of invasive Candida infection.     

Proliferative and cytotoxic responses to mannoproteins of Candida albicans by peripheral blood lymphocytes of HIV-infected subjects.

Mucosal candidiasis is one of the first opportunistic diseases in HIV-infected subjects. In order to understand the relationship between this disease and immunodeficiency to chemically defined, immunodominant Candida antigens, a mannoprotein fraction from C. albicans cell wall (GMP) was used to analyse proliferative and non-MHC-restricted cytotoxic responses of peripheral blood mononuclear cells (PBMC) from normal and HIV-infected subjects. In the former, GMP induced extensive blastogenesis, generation of powerful cytotoxicity against a tumour cell line (K562), and production of substantial amounts of interferon-gamma (IFN-gamma). Cultured PBMC from HIV-infected subjects manifested an early decreased ability for proliferative as well as differentiative cytotoxic responses to the candidal mannoproteins. This inability became clearly evident in subjects with stage III (CDC) of the disease, was total in CDC stage IV and occurred even in some subjects with a normal number of CD4+ cells. Low or absent response to GMP correlated with lack of response to tetanus toxoid. In contrast, both lymphoproliferative and cytotoxic responses to exogenous IL-2 was highly preserved at all stages of infection. The production of IFN-gamma in GMP-stimulated PBMC cultures critically fell to negligible values in most of the subjects in CDC stages II and III. Thus, the lowered or absent cell-mediated immune responses to candidal mannoprotein may be one factor to explain the early, elevated susceptibility of HIV-infected subjects to mucosal candidiasis. This study also shows that our mannoprotein preparation may be used as a probe to detect the overall efficiency of T cell responses in the above subjects.     

Adding Biotin to Parenteral Nutrition Solutions Without Lipid Accelerates the Growth of Candida albicans

Background: We have previously demonstrated that Candida albicans requires multivitamins (MVs) or lipid to increase rapidly in parenteral nutrition (PN) solutions. In this study, in detail, the effects of vitamins on the growth of C. albicans in PN solutions without lipid were investigated. Methods: In the 1st experiment, a commercial PN solution without lipid was supplemented with water-soluble vitamins (SVs: vitamins B₁, B₂, B₆, B₁₂ and C, folic acid, nicotinamide, biotin and panthenol), water-insoluble vitamins (IVs: vitamins A, D, E and K) or both (MVs). In the 2nd experiment, the test solutions were prepared by supplementing the PN solution with one of each or all of the SVs. In the 3rd experiment, another commercial peripheral PN (PPN) solution without lipid was supplemented with SVs, nicotinic acid, biotin or both nicotinic acid and biotin. In each of the experiments, a specified number of C. albicans organisms was added to each test solution, and all of the test solutions were allowed to stand at room temperature (23-26ºC). The number of C. albicans was counted at 0, 24, 48 and 72 hours after the addition of the organism. Results: In the 1st experiment, the C. albicans increased rapidly in the PN solution supplemented with the SVs, but increased slowly without the SVs, regardless of the addition of the IVs. In the 2nd experiment, the C. albicans increased rapidly in the PN solution supplemented with the SVs or biotin, but increased slowly with each of the other water-soluble vitamins. In the 3rd experiment, the C. albicans increased rapidly in the PPN solution supplemented with the SVs or biotin, but increased slowly with the addition of nicotinic acid. Conclusions: These results suggested that adding MVs or SVs to PN solutions without lipid promotes the growth of C. albicans, and that this effect is mostly attributable to biotin.     

Comparison of adherence of Candida albicans and Candida parapsilosis to silicone catheters in vitro and in vivo

Objective  Although Candida parapsilosis has been associated with device-related infections in the clinical settings, factors that contribute to this association have not been previously examined. The objectives of this study were to compare in vitro and in vivo the adherence to silicone catheters of: (1) Candida albicans vs. C. parapsilosis , and (2) invasive vs. colonizing isolates of C. albicans and C. parapsilosis .
Methods  The records of 840 patients who had had Candida species isolated at three teaching hospitals during a three-month period were reviewed. A total of 20 clinical isolates of each of C. parapsilosis and C. albicans were examined for their adherence to silicone catheters in vitro and in a rabbit model of percutaneously placed catheters. For each Candida species, ten invasive isolates that had caused clinical device-related infection and 10 colonizing isolates that had caused only device colonization were studied.
Results  Candida parapsilosis accounted for <5% of yeast isolates from all sites, while three-quarters were C. albicans . Candida parapsilosis was isolated proportionately more often from blood and/or devices than C. albicans (34.3% vs. 8.5%, respectively, P  < 0.0001). There were no significant differences in the degrees of adherence in vitro and in vivo between C. albicans and C. parapsilosis or between invasive and colonizing Candida .
Conclusion  Although C. parapsilosis was isolated proportionately more often from blood and/or devices than C. albicans in our studied population, there was no significant difference in the adherence of the two Candida species to silicone, nor between invasive and colonizing Candida in our in vitro and in vivo models. Factors other than microbial adherence may help explain the observed association of C. parapsilosis with device-related infections.     

The effect of oral bacteria on Candida albicans germ-tube formation

A total of eight bacterial isolates belonging to six species, and a select group of 12 oral Candida albicans isolates, were used to study the effect of bacteria on germ-tube formation. Briefly, each bacterial suspension (10(5-6) cells/ml) was mixed with a C. albicans suspension (10(7) cells/ml) and incubated at 37 degrees C for 90 min with bovine serum, and the percentage germ-tube-positive Candida cells was quantified using a haemocytometer, under light microscopy. In general, out of eight bacteria, Streptococcus sanguis SK21A, Streptococcus salivarius SK56, Escherichia coli ATCC 25922, and S. salivarius OBU3 suppressed germ-tube formation to varying degrees, with different C albicans isolates. Porphyromonas gingivalis Pg 50, Lactobacillus casei ATCC 7469 and Prevotella intermedia OBU4 elicited significant enhancement of germ-tube formation, whereas S. sanguis OBU 2 had no effect. E. coli ATCC 25922 was the only organism to show statistically significant suppression of germ-tube formation (p=0.0312). A significant increase in the germ tube production of C. albicans isolated from HIV-infected compared with HIV-free individuals was also noted. The current results tend to suggest that commensal and transient oral bacterial populations may selectively influence the differential expression of germ-tube-forming ability of C. albicans isolates.     

Starvation survival of Candida albicans in various water microcosms

Candida is a major Human pathogen causing a variety of infections and can survive for extended period of time in aquatic environment including marine and fresh water. In this study we compared a colorimetric XTT assay to colony forming units (CFU) count to evaluate the survival potential of Candida albicans incubated in water microcosms. Our results showed that cells maintain cultivability within a long period followed by a decline in cultivability and a drop of plate counts to less than 20 cell ml(-1) after 150 days in tap water, 190 days in rain water and 200 days in seawater. In addition we noted that 10% of cells viability was reached after 150 days in seawater, 180 days in rain water and 210 days in tap water. Molecular method confirms the persistence of C. albicans cells in water during long time starvation period.     

老年人口腔白色念珠菌的分布与基因分型研究

目的研究健康老年人口腔白色念珠菌的分布、基因型特点及基因型特点与白色念珠菌分布的相关性。方法来自成都地区212例老年人分为4组：A1（男性，有义齿）；A2（男性，无义齿）；B1（女性，有义齿）和B2（女性，无义齿）。CHROMagar Candida^TM鉴定培养基、碳水化合物同化反应鉴定体系（API 20C AUX）和随机扩增片段多态性分析（randomly amplified polymorphic DNA assays，RAPD）鉴定白色念珠菌。RAPD分析健康老年人口腔白色念珠菌分离株的基因型特征。统计学分析比较不同分组健康老年人口腔白色念珠菌基因型之间的差异。结果212例受检个体中检出89株白色念珠菌（42％），A1、A2、B1、B2白色念珠菌检出率分别为56．2％、21．3％、56．6％、38％。A1组与A2组白色念珠菌检出率差异有统计学意义，P〈0．01。以JWFP和NA为随机引物的RAPD分析将白色念珠菌分为5型。RAPD分析基因型构成在A1组与A2组之间比较差异有统计学意义，P〈0．05，A1组主要以A型为主。结论健康老年人口腔白色念珠菌的检出率与义齿修复相关。义齿修复可能促进具有特定基因型特点的白色念珠菌检出率增高。     

免疫功能低下Wistar大鼠白念珠菌肺炎模型的建立

目的建立用于免疫干预研究的免疫功能低下白念珠菌肺炎Wistar大鼠模型.方法醋酸考的松皮下注射制成大鼠免疫功能低下模型,并于第14天气管内灌注白念珠菌,制成免疫功能低下合并白念珠菌肺炎模型.检测免疫功能低下组,免疫功能低下+白念珠菌1、3、7?d组,正常组,正常+白念珠菌1、3、7?d组大鼠肺泡巨噬细胞的吞噬及杀菌功能;抗原提呈功能;培养上清中TNF-α活性和IL-1β、IL-6水平;血淋巴细胞杀伤功能;血清IFN-γ活性、IL-1β、IL-6水平;免疫功能低下+白念珠菌1、7?d组和正常+白念珠菌1、7?d组肺组织IFN-γ、TNF-α、IL-1β、IL-6表达;并于第7天进行左肺白念珠菌培养计数.结果免疫功能低下的大鼠肺泡巨噬细胞的吞噬和杀菌功能,抗原提呈功能,以及分泌TNF-α、IL-1β、IL-6的功能均明显低于免疫功能正常的大鼠;免疫功能低下的大鼠血中淋巴细胞的细胞毒作用明显低于免疫功能正常的大鼠;免疫功能低下的大鼠血清IFN-γ活性和IL-1β、IL-6水平明显低于免疫功能正常的大鼠.免疫功能低下合并白念珠菌肺炎大鼠肺组织IFN-γ、TNF-α、IL-1β、IL-6表达灌菌后第1天均低于白念珠菌肺炎大鼠,第7天均高于白念珠菌肺炎大鼠.免疫功能低下的大鼠左肺白念珠菌培养计数6.50×108CFU,免疫功能正常的大鼠左肺白念珠菌培养未见白念珠菌生长.结论该模型是免疫功能低下宿主肺部感染研究的适宜模型.     

白念珠菌在肠腔中的增殖与局部IgA抗体分泌的关系

目的 观察白念珠菌（白念菌）在肠腔内增殖与局部粘膜免疫反应的关系。方法 采用无特殊原菌动物经口喂入白念菌,在不同时相处死后,观察肠内白念菌总数及肠粘膜表面白念菌粘附数量;取肠系膜淋巴结做白念菌选择培养,观察移位体内发生率;采用Ｂｒｄｕ体内掺入显示局部粘膜淋巴细胞的增殖情况;流式细胞计数潘伊尔结细胞表面ＩｇＡ（ＳｍＩｇＡ）阳性率;免疫组化染色后计数固有层中ＩｇＡ浆细胞数量变化;ＥＬＩＳＡ法测定肠粘液     

肠内和肠外营养对上消化道肿瘤术后肠瘘患者的临床应用研究

目的提高上消化道肿瘤术后并发肠瘘患者的营养支持效率.方法 28例患者随机分为肠内和肠外营养支持两组,前者用市售普通营养制剂由空肠营养管持续滴入,进行管饲调节喂养.瘘口封闭后改由口服.后者采用深静脉置管,进行静脉营养支持.两组在热卡,糖、蛋白质、脂肪的组成比例及电介质、微量元素的含量等均相似.营养支持开始后第7、14、21、28、35天清晨空腹采血.检测血浆丙二醛（MDA）及超氧化物歧化酶（SOD）活力变化.测定血浆前白蛋白及转铁蛋白、血浆内毒素.结果肠内营养组的MDA及内毒素水平明显低于肠外营养支持组.结论肠内营养支持可保护肠道功能,减轻肠道缺血再灌注损伤,降低循环内毒素水平,明显改善患者的营养状态.     

Differential role of NK cells against Candida albicans infection in immunocompetent or immunocompromised mice

Little is known regarding the role of NK cells during primary and secondary disseminated Candida albicans infection. We assessed the role of NK cells for host defense against candidiasis in immunocompetent, as well as immunodeficient, hosts. Surprisingly, depletion of NK cells in immunocompetent WT mice did not increase susceptibility to systemic candidiasis, suggesting that NK cells are redundant for antifungal defense in otherwise immunocompetent hosts. NK‐cell‐depleted mice were found to be protected as a consequence of attenuation of systemic inflammation. In contrast, the absence of NK cells in T/B/NK‐cell‐deficient NSG (NOD SCID gamma) mice led to an increased susceptibility to both primary and secondary systemic C. albicans infections compared with T/B‐cell‐deficient SCID mice. In conclusion, this study demonstrates that NK cells are an essential and nonredundant component of anti‐C. albicans host defense in immunosuppressed hosts with defective T/B‐lymphocyte immunity, while contributing to hyperinflammation in immunocompetent hosts. The discovery of the importance of NK cells in hosts with severe defects of adaptive immunity might have important consequences for the design of adjunctive immunotherapeutic approaches in systemic C. albicans infections targeting NK‐cell function.     

特比萘芬与氟康唑或伊曲康唑联合对氟康唑诱导耐药稳定白念珠菌的影响

目的探讨特比萘芬与氟康唑或伊曲康唑联合抗氟康唑诱导产生的耐药稳定白念珠菌的作用.方法采用多步诱导法,在YEPD培养基中,利用氟康唑诱导白念珠菌敏感株产生耐药稳定菌株.根据美国国家临床实验标准委员会（NCCLS）制定的标准,采用棋盘微量稀释法测定特比萘芬与氟康唑或伊曲康唑对耐药稳定菌株的联合药敏试验,并对诱导耐药稳定菌株ERG11基因的编码区序列进行DNA测序.结果临床敏感菌株和标准敏感菌株能被诱导形成耐药菌株,但大部分不稳定,诱导耐药稳定株ERG11基因的编码区DNA测序有突变点存在,特比萘芬与氟康唑或伊曲康唑联用对诱导耐药稳定株可产生协同作用.结论特比萘芬与氟康唑或伊曲康唑联合应用对基因突变产生的耐药株有协同作用,可阻止或延迟氟康唑诱导的耐药性白念珠菌菌株的产生.     

白色念珠菌感染免疫应答的研究进展

白色念珠菌的致病是其与机体免疫系统相互作用的结果.研究发现,白色念珠菌感染人体时,刺激机体产生固有免疫及特异性细胞免疫和体液免疫应答.其中特异性细胞免疫占主导地位.了解认识白色念珠菌感染的免疫应答对诊断、预防及治疗白色念珠菌感染具有重要意义.     

Interferon-gamma activates the oxidative killing of Candida albicans by human granulocytes.

Although granulocytes are essential for the resistance against infections with Candida albicans, these cells do not kill the ingested yeast optimally. Various cytokines can enhance functional activities of granulocytes, but until now only interferon-gamma (IFN-gamma) has been applied more widely, namely in patients with chronic granulomatous disease. Since it is not certain whether IFN-gamma is able to enhance the candidacidal activity of granulocytes the present study was undertaken. Human granulocytes incubated with various concentrations of recombinant human IFN-gamma (rIFN-gamma) were studied for the phagocytosis and intracellular killing of C. albicans and their oxygen metabolism after stimulation with opsonized Candida. Results showed a small increase in the rate of phagocytosis and a dose-dependent increase of the intracellular killing of C. albicans and the production of H2O2. The increased candidacidal activity and H2O2 production by rIFN-gamma-stimulated granulocytes were inhibited by diphenylene iodonium (DPI). From these results it is concluded that the increased candidacidal activity of granulocytes activated by rIFN-gamma is caused by the increased production of reactive oxygen radicals.