氟烷在体外降低细菌的粘附性

人们普遍认为,麻醉可抑制机体的免疫系统,从而增加术后感染率,更有学者证实麻醉可抑制中性粒细胞及淋巴细胞功能,但麻醉剂本身对感染的影响仍属未知。细菌对粘膜上皮的粘附是引起感染的第一步,为了解挥发性麻醉剂是否会引起细菌对粘膜上皮粘附性的改变。作者选两种大肠杆菌用于对单层人上皮细胞(HEp-2)粘附测定。有外源凝集素K88菌毛的大肠杆菌株(血清分型O141:K88,K85a,c)在     

清利冲剂治疗急性肾盂肾炎动物模型的实验研究

目的：探讨清利冲剂治疗急性肾盂肾炎的治疗作用及机理。方法：用膀胱内注射大肠杆菌，一侧输尿管暂时结扎的方法建立大鼠急性逆行肾盂肾炎动物模型，观察清利冲剂治疗后肾脏大体形态，细菌学和病理学变化。结果：治疗后，治疗各组大鼠的患肾形态和病理明显改善，肾组织和尿细菌培养阳性率明显减少，尤以清利冲剂量组明显。结论：清利冲剂能有效地抑制患鼠尿液和左肾组织中细菌的生长，改善患肾的病理组织状态。     

转化生长因子β1对体外培养尿道细胞的生物学作用研究

目的 观察转化生长因子β1(TGF-β1)对尿道黏膜上皮细胞及成纤维细胞的生长调节作用及在诱导靶细胞结缔组织生长因子(CTGF)的表达中的作用.方法 体外培养尿道黏膜上皮细胞及成纤维细胞并鉴定.取第4代细胞分别设立对照组(以不含TGF-β1的细胞培养液培养)和实验组(分别以TGF-β11、2、4、8 μg/L的细胞培养液培养),24 h后分别以MTT比色试验和细胞计数法检测细胞活力,RT-PCR检测细胞内CTGF mRNA的表达.结果 与对照组相比较,实验组尿道黏膜上皮细胞数量和吸光度值随TGF-β1浓度升高而降低(P＜0.05),成纤维细胞数量和吸光度值随TGF-βl浓度升高而升高(P＜0.05);CTGF mRNA在实验组上皮细胞和成纤维细胞中均有表达,且表达水平随TGF-βl浓度升高而增加(P＜0.05).结论 TGF-β1可抑制尿道黏膜上皮细胞生长,促进成纤维细胞生长,并能诱导尿道黏膜上皮细胞及成纤维细胞表达CTGF mRNA.     

中药调控血小板衍化生长因子逆转早期糖尿病肾病机制的实验研究

目的 :观察益气活血补肾的治糖保肾冲剂对早期糖尿病肾病 (DN)大鼠肾皮质血小板衍化生长因子 -β(PDGF - β)蛋白及PDGF - βmRNA表达的影响 ,探讨其作用机理。 方法 :实验采用链脲佐菌素 (STZ)及福氏佐剂(CFA)诱发糖尿病肾病大鼠模型 ,造模成功后随机分为正常组、模型组、中药组 (治糖保肾冲剂 )、西药组 (苯那普利 ) ,治疗 4周后检测大鼠肾皮质PDGF - β蛋白及PDGF - βmRNA表达。 结果 :中药组治疗后尿微量白蛋白 (Ualb)明显低于模型组 ,有统计学差异 (P <0 .0 5 ) ;中药组治疗后PDGF - β蛋白及PDGF - βmRNA表达均明显低于模型组 (P <0 .0 1,P <0 .0 5 )。结论 :提示治糖保肾冲剂治疗早期DN的机理与抑制PDGF - β蛋白及PDGF - βmRNA表达有关     

MiR-21介导丹参多酚酸B在肾脏缺血/再灌注损伤中的保护作用

目的:探讨微小RNA 21(miR-21)介导丹参多酚酸B(salvianolic acid B,Sal B)在肾脏缺血/再灌注(ischemia/reperfusion,I/R)损伤中的保护作用。方法:构建肾脏I/R模型,术前1 h给予小鼠尾静脉注射Sal B,分为四组:(1)假手术组(Sham组)、(2)缺血再灌注组(I/R组)、(3)丹参多酚酸B干预组(SB+I/R组)和(4)生理盐水对照组(NS+I/R组)。四组均在再灌注后24 h处死小鼠,观察Sal B预处理对再灌注后24 h肾功能、肾组织病理评分、细胞凋亡、肾脏miR-21和程序性细胞死亡因子4(programmed cell death 4,PDCD4)表达变化的影响。体外给予人肾小管上皮细胞低氧/复氧和Sal B干预。锁核苷酸(LNA)修饰的anti-miR-21抑制miR-21表达(体外细胞转染),观察miR-21、PDCD4 mRNA和蛋白和细胞凋亡的变化。结果:在体外研究中,Sal B减轻肾小管上皮细胞低氧/复氧损伤,上调低氧/复氧细胞miR-21表达,降低PDCD4蛋白表达(P 0. 05)。抑制细胞miR-21表达则显著削弱Sal B的细胞保护作用,anti-miR-21明显上调细胞PDCD4蛋白的表达水平(P 0. 01),同时凋亡的细胞比例显著增加(P 0. 01)。肾脏I/R小鼠模型中,与I/R组、NS+I/R组相比,SB+I/R组小鼠肾功能和组织病理损伤显著减轻(P 0. 01); Sal B诱导再灌注后肾脏miR-21高表达,同时PDCD4蛋白表达有所下降(P 0. 01),伴有细胞凋亡显著减少(P 0. 05)。结论:Sal B诱导的miR-21通过抑制靶基因PDCD4的表达,减轻肾小管上皮细胞凋亡,从而对肾脏I/R损伤起到保护作用。     

fimH基因对泌尿道致病性大肠埃希菌1型菌毛粘附功能影响的初步探讨

目的 研究fimH基因对泌尿道致病性大肠埃希菌(UPEC)1型菌毛粘附功能的影响,比较1型菌毛粘附阳性与阴性菌株的基因变化.方法 对天津地区三家三级甲等医院(天津医科大学第二医院、天津市第一中心医院、天津市儿童医院)2012年1月至2013年1月非植入导尿管患者的尿液样本分离非重复感染大肠埃希菌171株进行研究,通过PCR检测fimH基因携带情况,酵母细胞粘附实验检测1型菌毛的粘附情况.针对fimH基因进行RT-PCR实验,消除转录对粘附作用的影响.采用常规x2检验和Yates校正x2检验比较fimH基因转录粘附阴性组与阳性组间fimH基因序列的改变.结果 天津地区UPEC菌株fimH基因携带率为83％,1型菌毛粘附率为57％,粘附阳性菌株均携带fimH基因.因fimH基因未转录导致粘附阴性的菌株占18％.第51位氨基酸位点粘附阳性组较阴性组更易发生突变(x2=6.64,P=0.010);第190位与第219位氨基酸位点于粘附阴性组各有6株菌和7株菌发生突变,而阳性组未见突变(x2=4.69和5.87,P值均＜0.05);粘附阴性组其余23株菌株无法用单核苷酸多态性改变解释其粘附阴性.结论 fimH基因的突变与缺失可以影响UPEC菌株1型菌毛粘附功能,除了转录调控外,还发现了可能引起1型菌毛粘附功能改变的3个关键位点;粘附过程中除fimH基因这一关键因素外,其他基因可能也会影响1型菌毛的粘附功能.     

苯肾上腺素对人前列腺上皮细胞增殖和凋亡的作用

目的　探讨交感神经递质对人前列腺上皮细胞增殖和凋亡的作用。方法　在不同浓度的苯肾上腺素下培养人良性前列腺增生 (BPH)上皮细胞系BPH1,观察苯肾上腺素对前列腺上皮细胞增殖和凋亡的影响及其能否被盐酸特拉唑嗪阻断。结果　苯肾上腺素能够刺激体外培养的人前列腺上皮细胞数量增加 ,r1=0 .82 1,P <0 .0 5 ) ;能够增加体外培养的人前列腺上皮细胞上清液A值的增加 ,r2 =0 .85 4,P <0 .0 5 ;能够增加体外培养的人前列腺上皮细胞S期细胞所占的比例(r3 =0 .85 0 ,P <0 .0 5 ) ,这种作用能被盐酸特拉唑嗪阻断。苯肾上腺素不能诱导或抑制体外培养的前列腺上皮细胞发生凋亡。结论　苯肾上腺素能通过α1受体途径刺激前列腺上皮细胞增殖。     

肾康注射液抑制高糖诱导肾小管上皮细胞应激性衰老

目的:观察肾康注射液对高糖诱导肾小管上皮细胞衰老的影响。方法:将体外培养的小鼠原代肾小管上皮细胞分为空白对照组、甘露醇组、高糖组、高糖+肾康注射液高、中、低剂量组。观察细胞形态及衰老标志SAHF、P16和SA-β-半乳糖苷酶的表达,测定超氧化物歧化酶(SOD)活性和丙二醛(MDA)含量,确定肾康注射液对高糖诱导肾小管上皮细胞应激性衰老的影响。结果:肾康注射液可以剂量依赖性的抑制高糖诱导的肾小管上皮细胞扁平肥大、SAHF、P16和SA-β-半乳糖苷酶的表达,减少MDA含量、增加SOD的活性。结论:肾康注射液可以通过抗氧化应激抑制高糖诱导肾小管上皮细胞应激性衰老。     

参附对再灌注期间肠粘膜上皮细胞凋亡的抑制作用及机制探讨

目的　探讨大鼠缺血 再灌注期间粘膜上皮细胞凋亡及参附注射液对其影响的可能机制。方法　采用大鼠肠缺血 再灌注模型 ,2 4只大鼠随机分为对照组 (C组 )、缺血 再灌注组 (I R组 )和参附治疗组 (SF组 )。在规定时间检测回肠粘膜上皮细胞Caspase 3、Bcl 2蛋白的表达、凋亡细胞数目及回肠粘膜组织肿瘤坏死因子 (TNF α)水平 ,同时观察病理形态学改变。结果　 (1)I R组凋亡细胞显著增多 ,SF组凋亡细胞数较I R组显著减少而多于C组 (P <0 0 5 )。 (2 )Caspase 3在I R组的表达显著高于SF组和C组 (P <0 0 1) ,SF组与C组差异无显著性。Caspase 3表达与凋亡细胞数目呈正相关 (r =0 914 9,P <0 0 1) ;Bcl 2的表达与Caspase 3的表达呈直线负相关 (r =- 0 9384 ,P <0 0 1)。 (3)TNF α表达 :TNF α的表达在I R组显著高于C组和SF组 (均P <0 0 1) ,SF组与C组差异无显著性。TNF α表达与凋亡细胞数目呈正相关 (r =0 9133,P <0 0 1)。 (4)SF组小肠粘膜病理损伤程度明显小于I R组 (P <0 0 1)。结论　参附注射液通过抑制TNF α、Caspase 3表达同时上调Bcl 2而抑制缺血 再灌注期间肠粘膜上皮细胞的凋亡 ,从而减轻肠粘膜缺血 再灌注损伤。     

右旋柠烯对胃癌细胞粘附和侵袭能力影响的研究

目的观察右旋柠烯对胃癌细胞粘附和侵袭行为的影响。方法用四唑氮蓝比色法检测右旋柠烯对胃癌细胞的抑制作用 ;以纤维粘连蛋白和层粘连蛋白为对象 ,检测右旋柠烯对胃癌细胞与细胞外基质粘附作用的影响 ;利用Transwell小室 ,以Matrigel和纤维粘连蛋白构建重组基底膜 ,检测右旋柠烯对胃癌细胞侵袭人工基底膜能力的影响 ;应用Westen blot法检测右旋柠烯对胃癌细胞条件培养液中基质金属蛋白酶 2 (MMP 2 )和组织金属蛋白酶抑制剂 2 (TIMP 2 )蛋白表达的影响。结果右旋柠烯对胃癌细胞的生长具有显著的抑制作用 ,并抑制胃癌细胞和细胞外基质的粘附及对重组基底膜的侵袭。右旋柠烯 (0 2 5mmol/L)作用后胃癌细胞培养液上清中TIMP 2表达升高(2 9 5± 0 6 ) ,MMP 2表达下降 (2 9± 0 3) ,与对照组比较差异有显著意义 (P <0 0 5 )。结论右旋柠烯对胃癌细胞SGC 790 1具有明显的细胞毒作用 ,并可能通过下调胃癌细胞MMP 2和上调TIMP 2的表达抑制其粘附和侵袭。     

Host defense within the urinary tract. I. Bacterial adhesion initiates an uroepithelial defense mechanism

Uroepithelial defense has been suggested to contribute to the local host resistance against ascending urinary tract infection. The cellular mechanism, however, is not known. In this study, bacterial growth was measured under the direct and indirect influence of uroepithelial cells. To study if a specific ligand-receptor interaction is required for uroepithelial cell (UEC) activation, isogenic Escherichia coli mutants expressing either mannose-sensitive, mannose-resistant (p), or mannose resistant (s) pili were tested for their capacity to induce the UEC defense mechanism. The antibacterial effect of UEC was abolished either by performing coculture in chambers with a fluid-permeable membrane which separates UEC from bacteria or by inhibiting membrane contact using the antiadherence factor pentosane polysulfate. No difference between the various types of pili could be shown. All E. coli strains adhered comparably to the UEC and were subsequently suppressed in their growth. Even a “naked” mutant without expression of common pili showed a similar behavior. In conclusion, bacterial growth suppression depends on direct contact between the UEC and bacteria, but is independent of common pili expressed on E. coli. Received July 29, 1995; received in revised form and accepted December 28, 1995     

THE SIGNIFICANCE OF THE DIFFERENCE IN BACTERIAL ADHERENCE BETWEEN BLADDER AND ILEUM USING RAT ILEAL AUGMENTED BLADDER

OBJECTIVES: Intestinal segments are frequently used in the reconstruction of the urinary tract. Chronic bacteriuria is frequently observed in these patients, but the reason is not clearly understood. Therefore, we studied the difference in bacterial adherence between bladder and ileum using the rat ileal augmented bladder model to investigate the cause of chronic bacteriuria. MATERIALS AND METHODS: Augmentation of the bladder using ileum and a sham operation were performed under sodium pentobarbital in 102 and 10 Sprague-Dawley rats, respectively. At three months after the operation, urinary pH and plasma concentration of sodium, chloride and potassium were measured and urinary culture was done. Urovirulence factors of Escherichia coli aspirated from augmented bladder were detected by polymerase chain reaction (PCR). Five to six rats with negative urinary cultures after the augmentation were used for each experimental cystitis. E. coli with type I pili aspirated from augmented rats and three clinically isolated strains of E. coli, C5 (type I pili, aerobactin), C92 (type I pili, aerobactin, P fimbriae), and C189 (type I pili, aerobactin, P fimbriae, CNF), were transurethrally inoculated into the augmented bladder of rats. Fourteen days after inoculation, rats were sacrificed and colony-forming units (CFU) per mg. of tissue of bladder and ileum were measured. RESULTS: After operation, urinary pH and the serum level of chloride in all augmented groups were higher than those of the controls. Bacterial colonization was observed in 56 of 89 rats. Most of them were E. coli having only type I pili as a virulence factor. In contrast, the sham operated group revealed no bacterial colonization. In experimental cystitis, E. coli with only type I pili aspirated from augmented rats and E. coli C5 were clearly adhered to ileum rather than to bladder, but E. coli C92 and C189 showed no significant difference with respect to adherence to the two tissues. In experimental cystitis II, E. coli C5 with D-mannose were washed out in 3 of 5 rats by 14 days, while E. coli C5 without D-mannose were not washed out in all rats by 14 days. CONCLUSIONS: These results suggested that the difference in bacterial adherence due to urovirulence factors, especially type I pili, is one of the main causes of asymptomatic bacteriuria after urinary reconstruction.     

Surface modification to improve in vitro attachment and proliferation of human urinary tract cells

OBJECTIVE: To evaluate the attachment and proliferation of cultured human urinary tract cells to culture plates surface-modified by photochemical immobilization of extracellular matrix (ECM) proteins. MATERIALS AND METHODS: Human uroepithelial (UEC) and smooth muscle (SMC) cells were harvested from ureter and expanded in culture; 24-well culture plates surface-modified by photochemical covalent immobilization of ECM proteins were then seeded with UEC or SMC. To characterize cellular attachment, cells were incubated on surface-modified plates for 30 and 90 min. For proliferation assays the cells were incubated for 3-12 days. Standard tissue culture plates with no surface modification and sham-modified plates served as controls. Differential attachment and proliferation on the various surfaces were assessed using analysis of variance with Fisher's posthoc test for multiple comparisons. RESULTS: Attachment at 30 and 90 min of both UEC and SMC on plates surface-modified with ECM proteins was significantly greater than in control plates. Surface-modification with collagen resulted in significantly greater cellular attachment than with either laminin or fibronectin. UEC proliferation was also significantly greater than in control plates by surface-modification with collagen and fibronectin, but not with laminin. SMC proliferation was significantly better after surface modification than on sham- modified plates, but was no better than standard plates. CONCLUSIONS: Covalent photochemical immobilization of ECM proteins to potential growth surfaces enhances the attachment of cultured UEC and SMC and the proliferation of UEC. This technique might be useful in modifying surface properties of synthetic polymer-based materials in a controlled and defined manner, giving them the capacity to promote and sustain the growth of urinary tract cells. This may lead to development of alternative methods of tissue engineering in the urinary tract.     

Diagnostic, therapeutic and healthcare management protocols in parathyroid surgery. 1st Consensus Conference

AIM: The aim of the study was to draw up a management protocol in parathyroid surgery promoted by the Italian Association of Endocrine Surgery Units (UEC Club), based on the guidelines of the main international scientific societies and shared by the experts and applied by the operators in the sector. METHODS AND CONSENSUS: The management protocols, already presented in 2003, on the occasion of the current review were examined by the 1st Consensus Conference called on the topic by the Italian Association of Endocrine Surgery Units (UEC). The Conference comprised two distinct sessions, the first in November 2006 within the framework of the 5th National Congress of the UEC Club in Verona, and the second in September 2007 within the framework of the 10th Multidisciplinary Scanno Prize Meeting. A selected board of endocrinologists and endocrine surgeons examined the individual chapters and submitted the consensus text for the approval of several experts. CONCLUSIONS: The diagnostic, therapeutic and healthcare management protocols in parathyroid surgery approved by the 1st Consensus Conference are officially those proposed by the Italian Association of Endocrine Surgery Units (UEC Club) and are subject to review by October, 2009.     

Adherence of E. coli to bladder epithelia in compromised mice and plasma endotoxin level]

The role of bacterial adherence in association with complicated urinary tract infections (UTI) and the correlation between bacterial adherence and plasma endotoxin (ET) levels were experimentally investigated by using mouse UTI models. Mice with foreign bodies induced in the bladder or voiding dysfunction were more susceptible to UTI than untreated mice. But diabetic or granulocytopenic mice were little susceptible to UTI in comparison with other two models. Adherence activities of 6 strains of E. coli to mice bladder epithelia in the 4 compromised models showed no difference when compared with those in normal control. Binding patterns of 8 kinds of lectins and mouse uromucoid polyclonal antibody to the mice bladder epithelia in compromised models appeared to be almost the same as those in the normal bladder epithelia. These results suggested that the reason for the susceptibility to UTI in the compromised mice was not necessarily explained based on the increased adherence of E. coli due to qualitative or quantitative changes in receptors on the bladder mucosa. Impairment of other host defense mechanisms may be considered in this regard. Three strains of E. coli expressing type 1 pili adhered to the bladder epithelia in greater numbers in vivo than non piliated strains. E. coli No. 113 strain expressing both type 1 and p pili appeared to be the most virulent in vivo among all 6 strains. Plasma ET levels increased 6 to 24 hours after inoculation of 2 strains of E. coli expressing only type 1 pili or p pili, while a little increase in the levels was observed in mice inoculated with non piliated E. coli. Bacterial adherence to the bladder epithelia may play an important role for the increase in ET levels.     

Host defense within the urinary tract. II. Signal trasducing events activate the urepithelial defense

It has been shown previously that the interaction between uroepithelial cells (UEC) from healthy donors and adherent Escherichia coli suppresses bacterial growth in vitro. The following study was performed to investigate the nature of membrane signal transduction mechanisms involved in this process. UEC/E. coli cocultures were established in the presence of substances known to modulate transmembranous signals. Inhibition of calcium flux, either by calcium channel-blocking substances or by a calmodulin antagonist, depressed the antibacterial UEC function of “healthy” UEC. In contrast, receptor/ligand-induced stimulation of G-proteins, activation of the adenylate cyclase, and the increase of intracellular cyclic AMP levels by cytoplasmatic phosphodiesterase did not increase the antibacterial capacity of healthy UEC. However, the antibacterial function of defense-deficient UEC from patients with recurrent idiopathic urinary tract infection could be reconstituted by this treatment to almost normal levels. In conclusion, the antibacterial UEC defense function is activated by transmembranous signals from bacteria attached to the host cell surface. Activation involves the adenylate cyclase pathway. Activation of the phosphoinositol pathway may contribute to intracellular calcium fluxes. Received July 20, 1995; received in revised form and accepted December 28, 1995     

Bacterial adherence in a rat bladder augmentation model: ileocystoplasty versus colocystoplasty

PURPOSE: Various intestinal segments are used to reconstruct the urinary tract. For unclear reasons asymptomatic chronic bacteriuria is common in patients treated with reconstruction. We compared bacterial adherence in ileum, colon and bladder in rats with ileal and colonic bladder augmentation. MATERIALS AND METHODS: Bladder augmentation using ileum or colon was performed in 8-week-old rats. After 3 months urinary pH was measured and urine was cultured. Urovirulence factors of Escherichia coli aspirated from the augmented bladders were detected by polymerase chain reaction. In rats with negative urine culture after augmentation experimental cystitis was induced by the transurethral inoculation of E. coli C5, with type I pili and aerobactin or E. coli C92 with type I pili, P fimbriae and aerobactin at a concentration of 10(5) colony forming units per 0.3 ml. After 14 days we counted the colony forming units per cm.(2) of bladder and cm.(2) of intestinal augmentation tissue. RESULTS: When cultures were negative, mean urinary pH plus or minus standard deviation for ileocystoplasty (7.35 +/- 0.33) was significantly higher than that for colocystoplasty (6.80 +/- 0.45) or in controls (6.67 +/- 0.30). Bacterial colonization occurred in 60 of 96 ileocystoplasties (62.5%) and 36 of 68 colocystoplasties (52.9%). All 32 E. coli strains aspirated from ileocystoplasties had type I pili. In colocystoplasties 14 strains had type I pili, 4 had P fimbriae and type I pili, and 1 had no virulence factor. In experimental cystitis in the ileal patch and bladder there were 10(3.2) to 10(6.2) (log mean 4.9) and 10(1.1) to 10(5.1) (log mean 3.5) colony forming units of E. coli C5, respectively. In the colonic patch and bladder there were 10(2.2) to 10(6.2) (log mean 3.9) and 10(2.1) to 10(5.1) (log mean 3.7) colony forming units of E. coli C5, respectively. In the ileal patch and bladder versus the colonic patch and bladder there were 10(3.2) to 10(6.2) (log mean 5.0) and 10(3.1) to 10(6.1) (log mean 4.5) versus 10(3.2) to 10(6.2) (log mean 4.3) and 10(2.1) to 10(6.1) (log mean 3.8) colony forming units of E. coli C92, respectively. E. coli C5 adhered to more ileum than bladder, while bacterial adherence did not differ for colon and bladder. Adherence of E. coli C92 did not differ significantly in bladder and implanted ileum or colon. CONCLUSIONS: The colonic segment offers more resistance to E. coli than the ileal segment in urinary diversion.     

The Interaction of Buccal Mucosal Epithelial Cells with E. coli Bacteria Enhances the Intraepithelial Calcium Flux and the Release of Prostaglandin E2 (PgE2)

Mucosal epithelial cells contribute significantly to host defense mechanisms. Uroepithelial cells (UEC) from healthy donors suppress bacterial growth in vitro. Bacterial adherence to UEC has been shown to be a prerequisite. Similar results have been shown for buccal epithelial cells (BEC). The host response triggered by the host–parasite interaction seems to involve signal transduction and intracellular activation of second messengers. In this study the intraepithelial calcium flux was analyzed in individual BEC after bacterial contact. BEC were derived from scrapes of the buccal mucosa and labelled with fluo-3 (a calcium indicator). Thereafter the cells were analyzed immediately with a FACscan flowcytometer. The intracellular events were evaluated before and after the addition of viable E. coli bacteria (strain 4389, K1O1H7, pili II pos.). For control, the influence of prostaglandins, histamine, PMA, LPS and opsonized avital E. coli on the epithelial calcium flux was investigated. Additionally, supernatants of BEC-E. coli cocultures were analyzed with respect to their PgE₂ content. PgE₂ concentrations in supernatants of BEC, cultured alone or together with E. coli, were measured by a commercial PgE₂ ELISA kit. The addition of vital E. coli to BEC was promptly answered by a significant intracellular calcium flux. PgE₂, histamine and PMA, but not PgF_2α, PgE₁, LPS and opsonized E. coli, increased intracellular calcium. BEC alone did not release PgE₂. After coculture with E. coli increased levels of PgE₂ were measured in the supernatants. PgE₂ release was still enhanced by coactivation of the BEC with phorbolester (PMA). Our results confirm that calcium flux in mucosal epithelial cells is stimulated by the cell–bacteria contact. We suggest that the increased PgE₂ release amplifies the stimulation of intraepithelial second messengers. The resulting cell activation may lead to the secretion of antimicrobial peptides, thereby contributing to the regulation of mucosal host resistance to bacterial infections.     

Microbial and host factors that influence adherence of Escherichia coli to kidney epithelium

The adherence of Escherichia coli 06K13H1 to punch biopsy specimens of rabbit renal pelvic tissue and isolated epithelial cells was examined quantitatively. Organisms with pili adhered readily to kidney tissue, whereas organisms without pili (nonpiliated or grown in glucose-containing media) had significantly less adherence. Adherence was inhibited by antibody to pili antigen but not by mannose (a determinant of adherence to buccal mucosal cells). Studies were done to evaluate adherence under conditions operative in the renal medulla. The combination of hypertonic salt or urea solutions in acid pH interfered with adherence of the mannose-resistant strain. In additional studies of kidneys from humans, a similar effect of antipili serum and mannose was seen. These studies provide further evidence that pili are important in the initiation of upper urinary tract infection and define host factors that may inhibit initiation of infection.