诱导分化的骨髓间充质干细胞不同途径移植治疗慢性肝损伤的研究

目的 探讨诱导分化的骨髓间充质干细胞(MSC)不同途径移植治疗慢性肝损伤的可行性.方法 密度梯度离心法联合贴壁培养分离、扩增骨髓MSC,体外诱导向肝系细胞分化,反转录-聚合酶链反应(RT-PCR)、免疫细胞化学法检测肝系细胞标志,电镜观察超微结构的变化.清洁级Wistar大鼠120只,其中114只建立慢性肝损伤模型(实验组),另6只作为正常对照组.实验组8周内自然死亡12只,将剩余96只根据三种移植途径及体质量分层随机均分为门静脉移植实验组、门静脉移植对照组、脾脏移植实验组、脾脏移植对照组、尾静脉移植实验组和尾静脉移植对照组,各移植实验组移植4',6-二脒基-2'-苯基吲哚(DAPI)标记诱导分化14 d的MSC,观察移植后细胞的迁徙、定位,血清肝功能指标,肝脏组织病理学及移植效果.结果 诱导后第7、14天均检测到甲胎蛋白(AFP)mRNA表达,第14、21天检测到白蛋白(ALB)mRNA、兔抗鼠细胞角蛋白18(CK18)和肝细胞抗原表达.诱导后MSC胞体增大,胞质中含有较多线粒体、粗面内质网、高尔基体、溶酶体和糖原颗粒等.各移植实验组大鼠均发现DAPI标记细胞且丙氨酸转氨酶等肝功能指标及肝脏病变程度均较其移植对照组改善,以脾内移植途径更为显著[(98.13±8.22)U/L比(145.85±15.88)U/L,P＜0.05].结论 诱导分化的骨髓MSC通过三种移植途径均对慢性肝损伤具有修复作用,且脾内移植优于门静脉及尾静脉移植.     

受者同系骨髓间充质干细胞对大鼠心脏移植急性排斥反应的影响

目的观察受者同系骨髓间充质干细胞（MSC）对大鼠心脏移植急性排斥反应的影响,并初步探讨其免疫调节机制。方法成年雄性Wistar大鼠20只为受体,随机分为空白对照组和MSC处理组,每组10只,行Lewis大鼠→Wistar大鼠颈部心脏移植。空白对照组手术后24h,经尾静脉注射3ml 0.9%氯化钠注射液;MSC处理组手术后24h,经尾静脉注射MSC2×10~6（悬浮在3ml 0.9%氯化钠注射液中）。术后1周,每组随机取4只大鼠,进行组织学检查及下腔静脉血检测血清白介素（IL）-2及IL-10水平。其余6只用以继续观察移植物存活时间。结果 （1）空白对照组大鼠移植心脏存活（7.2±1.3）d,MSC处理组大鼠移植心脏存活（14.8±2.9）d,差异显著（P〈0.01）。（2）血清IL-2空白对照组为（233.99±30.19）ng/L,MSC处理组为（249.11±20.34）ng/L,两组无统计学差异（P〉0.05）;血清IL-10空白对照组为（81.44±11.01）ng/L,MSC处理组为（158.39±18.70）ng/L,差异显著（P〈0.01）。（3）病理学分级,空白对照组3B级1例、4级3例,MSC处理组2级1例、3A级2例、3B级1例,MSC处理组病理分级总体较空白对照组低。结论静脉注射受者同系骨髓MSC,可以延长大鼠颈部移植心脏的存活时间,减轻急性排斥反应的程度。     

经静脉途径移植骨髓间充质干细胞修复梗死心肌的可行性与安全性研究

目的探讨经静脉注射移植同种异体骨髓来源间充质干细胞(MSC)修复损伤心肌是否可行和安全,观察移植MSC在宿主的归巢与组织学分布。方法雄性Wistar大鼠30只,分为正常大鼠MSC移植组,急性心肌梗死MSC移植组,假手术组,每组10只。结扎冠状动脉左前降支,建立大鼠急性心肌梗死模型。体外分离纯化、扩增同种大鼠骨髓MSC,于建立心肌梗死模型24h给各组大鼠经静脉输注4’6’二乙酰基2苯基吲哚(DAPI)标记的MSC,4周后处死、摘取心脏等脏器,行组织病理切片和免疫组织化学染色。结果(1)在急性心肌梗死MSC移植组,梗死区及其周边部位可见到DAPI标记的MSC;(2)在梗死心肌周边区,移植的MSC胞浆心肌特异性蛋白肌钙蛋白I和转录因子4免疫组织化学染色阳性;(3)在各组大鼠其他脏器,移植的MSC主要分布在肺脏、脾脏和肝脏;(4)细胞移植大鼠心肌组织切片未见淋巴细胞增殖,各脏器没有肿瘤形成。结论经静脉移植的MSC可归巢至大鼠梗死心肌部位,并分化为心肌细胞表型,该方法治疗缺血性心脏病安全、可行。     

多次移植人脐带间充质干细胞对大鼠Th1和Th2比值的影响

目的:观察多次静脉移植人脐带间充质干细胞(human umbilical mesenchymal stem cells,HUMSCs)对大鼠Th1和Th2轴的影响。方法:①体外培养HUMSCs;流式细胞仪鉴定第4代hUMSCs表面抗原的表达;特异性诱导染色并鉴定第4代HUMSCs分化脂肪细胞和成骨细胞的潜能;②雄性SD大鼠30只,体质量182²03g,分为3组:空白对照组;0.9%氯化钠液组;干细胞移植组,每组10只。干细胞移植组:1次/w经尾静脉注射3.5×107/kg的HUMSCs,连续3次。第三次移植HUMSCs后11d,各组经腹主动脉取血,流式细胞仪检测T淋巴细胞的IFN-γ和IL-4阳性率。结果:3次注射干细胞后实验动物全部存活,干细胞组的Th1、Th2阳性率较0.9%氯化钠液组差异无统计学意义(P>0.05);Th1/Th2比值、血清IFN-γ和IL-4水平与对照组比较差异无统计学意义(P>0.05);干细胞组的心、脑、肺、肝及肾等脏器未发生病理改变。利用红色荧光蛋白转染的HUMSCs示踪,发现移植的HUMSCs大部分归巢于骨髓中。结论:多次尾静脉注射HUMSCs,未引起大鼠Th1、Th2细胞免疫和体液免疫系统的变化,Th1/Th2轴无明显改变。移植的HUMSCs能较长时间的存活于大鼠骨髓内,具有较好的免疫相容性。     

骨髓间充质干细胞移植治疗大鼠急性肝功能衰竭

目的探讨骨髓间充质干细胞（BMSCs）移植对急性肝功能衰竭的治疗作用。方法大鼠90%肝脏切除制备急性肝功能衰竭模型,实验组大鼠肝内移植2×106个BMSCs,对照组仅注射生理盐水。观察大鼠的生存情况,RT-PCR检测BMSCs在肝脏的植入,血清检测肝功能确认BMSCs移植对肝脏修复的作用。结果移植BM-SCs的实验组大鼠存活80%,对照组大鼠仅存活20%。RT-PCR显示,BMSCs移植后定植于大鼠肝脏内。肝功能检测显示,实验组大鼠的血清丙氨酸氨基转移酶水平、天冬氨酸氨基转移酶水平显著降低,血清白蛋白水平显著升高。结论 BMSCs移植可以显著提高急性功能衰竭大鼠的生存率,促进其肝功能的恢复,对急性肝功能衰竭的治疗具有积极作用。     

大鼠自体移植静脉内膜增生模型的改进

目的改进大鼠自体移植静脉内膜增生模型。方法将36只SD大鼠随机分成实验组和对照组。实验组采用套管法将大鼠白体颈外静脉移植入同侧颈动脉系统。对照组采用吻合法行自体颈外静脉移植，术后均皮下注射肝素800U／kg，2次／d，共5d。观察术后不同时间点两组大鼠移植静脉通畅性、吻合口狭窄及内膜增生情况。结果实验组移植静脉自体移植静通畅性优于对照组，吻合口狭窄程度轻于对照组。结论实验组模型设计科学，操作简便，成功率高。     

乌司他丁对大鼠超长皮瓣存活的影响

36只SD大鼠随机分成实验组和对照组各18例,在大鼠背部形成一蒂在尾端的2 cm×8 cm的随意皮瓣模型.实验组分别在术前10 min、术后12 h经尾静脉注射乌司他丁10万U/kg,对照组同法给予等量生理盐水.术后24 h,两组各取8只大鼠,处死后取皮瓣组织检测髓过氧化物酶（MPO）、丙二醛（MDA）水平;另10只大鼠,养至术后10 d,分析皮瓣存活情况.结果 实验组皮瓣术后24 h MPO和MDA均低于对照组（P＜0.05）,术后10 d皮瓣存活面积百分比明显高于对照组（P＜0.01）.认为围手术期使用乌司他丁能促进大鼠超长随意皮瓣的存活.     

脂肪间质干细胞移植对大鼠肝硬化模型的治疗作用

目的:探讨脂肪间质干细胞经门静脉及尾静脉移植后,对CCl4诱导的大鼠肝硬化模型的治疗作用.方法:SD♂大鼠45只随机分为对照组、门脉移植组及尾静脉移植组.所有大鼠经腹腔皮下注射CCl4混合物8 wk.第6周时门静脉组及尾静脉组分别从肠系膜上静脉及尾静脉注射大鼠脂肪间质干细胞悬液每只2 mL(细胞数量为2×106个),对照组自尾静脉注射等容量的细胞培养液.细胞移植前后取血检测肝功能指标.取肝脏标本并行包埋切片,HE染色后显微镜下观察各标本肝细胞变性坏死及肝硬化程度并进行病理评分.对所有实验数据行统计学分析.结果:门静脉及尾静脉移植组大鼠的肝功能指标(AST、ALT、ALB)较对照组有明显改善(142.2±31.2 U/L,167.9±28.3 U/L vs 354.2±26.4 U/L; 79.4±18.9 U/L,85.8±21.4 U/L vs456.7±35.3 U/L; 26.3±2.0 g/L,24.5±2.2 g/Lvs 17.2±1.7 g/L,均P<0.05),但TBIL没有明显改善.与对照组相比,脂肪干细胞移植能抑制肝组织的变性坏死和纤维化形成.病理评分比差异有统计学意义(P<0.05).结论:经门静脉及尾静脉移植脂肪间质干细胞对大鼠肝硬化模型有治疗作用,能改善肝功能及肝硬化程度.     

干细胞移植对大鼠实验性结肠炎的研究

目的 探讨异体骨髓造血干细胞(HC)和间充质干细胞(MSC)移植对大鼠实验性结肠炎(EC)的作用.方法 体外分别传代培养雄性大鼠的MSC和HC备用.实验1组的HC悬液以5-溴-2-脱氧尿嘧啶(BrdU)标记;实验2组用贴壁法获得MSC.72只雌性大鼠用三硝基苯磺酸灌肠法建立EC模型,造模后24 h,实验1组和实验2组经尾静脉分别注入HC和MSC悬浮液(每组18只),两实验组的对照组(每组18只)注入0.9%氯化钠溶液.于移植后第7、14和21天取结肠组织行病理学检查.实验1组采用SP免疫组化法检测BrdU阳性细胞,实验2组用PCR检测Y染色体的性别决定区段(sry),以确定干细胞的定位情况.结果 EC造模成功.MSC和HC培养生长迅速,均一性好.移植第7、14、21天时,实验1组病变区BrdU阳性的HC检出率均为6/6.实验2组sry阳性的MSC检出率分别为1/6、2/6和3/6.而对照组均为阴性.但两移植组的病理组织学改善均不显著.结论 HC和MSC均可在大鼠EC模型的病变肠道中定植,但移植不显著改善组织病理学,MSC定植率比HC低.     

骨髓间充质干细胞颈内动脉移植在血管性痴呆大鼠脑内存活迁移及对胆碱能系统的影响

目的观察颈内动脉移植骨髓间充质干细胞(MSC)透过血脑屏障在血管性痴呆(VaD)大鼠脑内存活、迁移及对海马乙酰胆碱(Ach)含量、乙酰胆碱酯酶(AchE)活性和认知能力的影响。方法选72只Wistar大鼠分为对照组、模型组和治疗组,每组又分4、8周2个时相点,每时相点12只。制作VaD大鼠模型,治疗组于术后24h颈内动脉移植0.5ml骨髓MSC。移植4、8周后检测移植细胞在VaD大鼠脑内存活、迁移及学习记忆能力,并检测海马区Ach含量及AchE活性。结果颈内动脉移植后4周骨髓MSC在VaD大鼠脑实质中广泛分布,主要聚集至海马、大脑皮质等缺血易损伤区域。与对照组比较,模型组和治疗组术后4、8周大鼠学习记忆显著降低(P<0.01);与模型组比较,治疗组术后4、8周大鼠学习记忆显著改善(P<0.01),细胞移植后治疗组Ach含量和AchE活性显著升高,差异有统计学意义(P<0.01)。结论骨髓MSC颈内动脉移植后可透过血脑屏障明显改善VaD大鼠胆碱能系统的功能,调节脑内Ach生理代谢,促进缺血损伤后脑组织的修复与再生,增强学习记忆能力。     

Clinical management of inflammatory bowel disease in the organ recipient

There was estimated a higher incidence of de novo inflammatory bowel disease(IBD)after solid organ transplantation than in the general population.The onset of IBD in the organ transplant recipient population is an important clinical situation which is associated to higher morbidity and difficulty in the medical therapeutic management because of possible interaction between anti-reject therapy and IBD therapy.IBD course after liver transplantation(LT)is variable,but about one third of patients may worsen,needing an increase in medical therapy or a colectomy.Active IBD at the time of LT,discontinuation of 5-aminosalicylic acid or azathioprine at the time of LT and use of tacrolimusbased immunosuppression may be associated with an unfavorable outcome of IBD after LT.Anti-tumor necrosis factor alpha(TNFα)therapy for refractory IBD may be an effective and safe therapeutic option after LT.The little experience of the use of biological therapy in transplanted patients,with concomitant anti-rejection therapy,suggests there be a higher more careful surveillance regarding the risk of infectious diseases,autoimmune diseases,and neoplasms.An increased risk of colorectal cancer(CRC)is present also after LT in IBD patients with primary sclerosing cholangitis(PSC).Anannual program of endoscopic surveillance with serial biopsies for CRC is recommended.A prophylactic colectomy in selected IBD/PSC patients with CRC risk factors could be a good management strategy in the CRC prevention,but it is used infrequently in the majority of LT centers.About 30%of patients develop multiple IBD recurrence and 20%of patients require a colectomy after renal transplantation.Like in the liver transplantation,anti-TNFαtherapy could be an effective treatment in IBD patients with conventional refractory therapy after renal or heart transplantation.A large number of patients are needed to confirm the preliminary observations.Regarding the higher clinical complexity of this subgroup of IBD patients,a close multidisciplinary approach between an IBD dedicated gastroenterologist and surgeon and an organ transplantation specialist is necessary in order to have the best clinical management of IBD after transplantation.     

应对肝源短缺问题的策略探讨

世界卫生组织发布的数据显示,中国有1.4亿乙型和丙型肝炎病毒携带者,约占全球乙、丙两型肝炎病毒携带者的28％;其中有3200万慢性活动性肝病患者;年发病人数3000万,每年有40万人死于病毒性肝病[1].由于社会生活方式和饮食习惯的改变,过去西方国家较多发的脂肪肝、药物性和酒精性肝炎、肝硬化等肝病也在我国逐渐增多[2].另外我国现有29.7万肝癌患者,占全球肝癌患者总和的一半以上[3].所以,肝病是影响我国生产力和社会安定的重大疾病.目前对急重型肝炎和肝癌等晚期肝病治疗的临床疗效不佳.原位肝移植是目前国际公认的有效方法[4-5].然而,由于肝脏供体的稀缺及高昂的治疗费用,使众多的重型肝病和肝衰竭患者得不到及时救治而死亡.寻求一种新的治疗措施和解决肝源的严重稀缺成为当务之急,也引起世界卫生组织和我国政府的高度重视[6].本文分析和回顾了目前世界范围内科学技术研究应对肝源短缺的前沿领域和方法,并提出了开源节流的相关策略,期望对我国肝源短缺、病患难以得到治疗的情况有所缓解,以探讨临床治疗的新希望.     

老年人肾移植术后重症肺炎的特点及诊治

目的 探讨老年人肾移植术后重症肺炎的的特点及诊治过程中采取的必要措施. 方法 回顾分析28例肾移植术后重症肺炎患者的临床资料,其中<60岁20例,≥60岁8例. 结果 <60岁组重症肺炎发生在术后1～13个月,均有发热,咳嗽10例,咳痰8例;Ⅰ型呼吸衰竭6例,Ⅱ型呼吸衰竭3例;大叶性肺炎6例,间质性肺炎13例,肺实变1例;病原体不明4例,病原体明确者16例,其中单纯细菌性肺炎4例、巨细胞病毒性肺炎4例、卡氏肺囊虫性肺炎2例、支原体感染1例、结核感染1例、混合感染4例(细菌+病毒2例、细菌+真菌1例、细菌+结核1例).病程初期均给与广谱抗生素、抗病毒、抗真菌药物全覆盖治疗(哌拉西林他佐巴坦/左氧氟沙星+大扶康+更昔洛韦).后期依据病原学结果 给与相应治疗.全覆盖治疗无效时及时给予糖皮质激素或免疫球蛋白治疗.治愈17例,死亡3例.≥60岁组肺炎发生在术后1～9个月.亦均有存在发热,咳嗽5例,咳痰3例;Ⅰ型呼吸衰竭3例,Ⅱ型呼吸衰竭1例.大叶性肺炎3例,间质性肺炎5例;病原体不明3例,病原体明确者5例,其中单纯细菌性肺炎2例,巨细胞病毒性肺炎1例,混合性肺炎2例(细菌+巨细胞病毒1例.细菌+真菌1例).采取与<60岁组同样的治疗方案,治愈5例,死亡3例. 结论 老年人肾移植术后重症肺炎,以术后1～9个月多发.致病体以细菌及巨细胞病毒为主.早期宜采用抗细菌+抗病毒+抗真菌感染的全封闭式联合用药,并及时使用呼吸机辅助通气.明确致病体后使用窄谱抗生素或抗病毒药物.对不明病原体感染者,应用糖皮质激素或免疫球蛋白治疗可取得较好疗效.     

Live donors in liver transplantation

Living donor liver transplantation (LDLT) has been controversial since its inception. Begun in response to deceased donor organ shortage and waiting list mortality, LDLT was initiated in 1989 in children, grew rapidly after its first general application in adults in the United States in 1998, and has declined since 2001. There are significant risks to the living donor, including the risk of death and substantial morbidity, and 2 highly publicized donor deaths are thought to have contributed to decreased enthusiasm for LDLT. Significant improvements in outcomes have been seen over recent years, and data, including from the National Institutes of Health-funded Adult-to-Adult Living Donor Liver Transplantation Cohort Study (A2ALL), have established a survival benefit from pursuing LDLT. Despite this, LDLT still composes less than 5% of adult liver transplants, significantly less than in kidney transplantation where living donors compose approximately 40% of all transplantations performed. The ethics, optimal utility, and application of LDLT remain to be defined. In addition, most studies to date have focused on posttransplantation outcomes and have not included the effect of the learning curve on outcome or the potential impact of LDLT on waiting list mortality. Further growth of LDLT will depend on defining the optimal recipient and donor characteristics for this procedure as well as broader acceptance and experience in the public and in transplant centers.     

骨髓间充质干细胞移植对急性胰腺炎后肠黏膜屏障的影响

目的 研究大鼠骨髓间充质干细胞(MSC)在急性胰腺炎后肠黏膜损伤修复中的作用.方法 从雄性SD大鼠股骨骨髓腔获取并培养MSC.20只雌性SD大鼠分成3组:急性重症胰腺炎(SAP)组(n=6)和MSC治疗组(n=8),均分2次以腹腔内注射L-精氨酸(2 g/kg)造模,成模12 h后,MSC治疗组予尾静脉注射MSC 5×...     

CD34~+细胞含量对自体骨髓干细胞移植治疗肝硬化疗效的影响

目的研究分离骨髓干细胞后CD34+细胞含量对自体骨髓干细胞移植治疗肝硬化疗效的影响。方法回顾性分析自体骨髓干细胞移植治疗肝硬化病例41例,其中CD34+细胞含量不足5%的27例,CD34+细胞含量超过5%(含5%)的14例。分析上述病例术后2～4周的实验室检测指标。结果在CD34+细胞含量不足5%的病例中,患者术后的血清总蛋白、白蛋白(Alb)、碱性磷酸酶(ALP)和血小板(PLT)均较术前明显增高(P<0.05)。在CD34+细胞含量超过5%的病例中,患者术后的血清总蛋白、Alb较术前明显增高(P<0.05)。术前CD34+细胞含量超过5%病例组的PLT平均值[(88.357±38.454)×109/L]明显低于CD34+细胞含量不足5%的病例组[(132.590±127.260)×109/L]。结论自体骨髓干细胞移植可以有效的提升肝硬化患者血清总蛋白和Alb水平,本组病例中CD34+细胞含量的不同并未明显影响术后患者血清总蛋白、Alb的恢复水平。自体骨髓干细胞移植可能影响胆汁的排泌。两组病例脾功能亢进程度不同可能是导致患者CD34+细胞含量差异的原因。     

非生物人工肝联合肝移植治疗中晚期慢性重型肝炎

目的评价非生物人工肝支持系统（ALSS）联合肝移植治疗巾晚期慢性重型肝炎的临床应用价值。方法采用ALSS联合肝移植治疗28例中晚期慢性重型肝炎患者，观察治疗前后各项临床指标的变化与疗效，并就治疗后生存率与同期内科治疗组99例患者、内科联合ALSS治疗组30例患者比较。数据行t和x^2检验。结果28例患者共成功进行57次ALSS治疗，TBil、PT、胆汁酸、BUN、Cr、血氨等指标明显好转（P〈0．05），临床症状改善的中位时间为3d（1～153d）。28例均顺利完成肝移植术，等待到供肝的中位时间为20d（1～153d），术后3、6个月生存率（71．d％，71．4％）显著高于内科治疗组（18．2％，11．1％）和内科联合ALSS治疗组（36．7％，26．6％）（P〈0．01）。结论术前应用非生物人工肝治疗，可有效改善中晚期慢性重型肝炎患者的病情，为顺利过渡到肝移植发挥桥梁支持作用。人工肝联合肝移植是有效治疗中晚期慢性重型肝炎的可靠方法。     

Prognostic significance of the hepatopulmonary syndrome in patients with cirrhosis

BACKGROUND AND AIMS: The hepatopulmonary syndrome (HPS) has been defined by chronic liver disease, arterial deoxygenation, and widespread intrapulmonary vasodilation. Mortality of patients with HPS is considered to be high, but the effect of HPS on survival in patients with cirrhosis remains unclear. METHODS: A total of 111 patients with cirrhosis were studied prospectively by using transthoracic contrast echocardiography for detection of pulmonary vasodilation, blood gas analysis, and pulmonary function test. Twenty different clinical characteristics and survival times were noted. RESULTS: Twenty-seven patients (24%) had HPS. Their mortality was significantly higher (median survival, 10.6 months) compared with patients without HPS (40.8 mo, P < 0.05), even after adjusting for liver disease severity (2.9 vs. 14.7 months in Child-Pugh class C with [n = 15] and without HPS [n = 35, P < 0.05]; 35.3 vs. 44.5 months in Child-Pugh class B with [n = 7] and without HPS [n = 23, P = NS]), and exclusion of patients who underwent liver transplantation during follow-up (median survival 4.8 vs. 35.2 months, P = 0.005). Causes of death were mainly nonpulmonary and liver-related in the 19 patients with and the 35 patients without HPS who died. In multivariate analysis, HPS was an independent predictor of survival besides age, Child-Pugh class, and blood urea nitrogen. Mortality correlates with severity of HPS. CONCLUSIONS: The presence of HPS independently worsens prognosis of patients with cirrhosis. This should influence patient management and scoring systems and accelerate the evaluation process for liver transplantation.     

2008年肝移植内科问题的研究进展

作为一个器官的疾病,终末期肝脏疾病的处理包括了内科和外科的处理,肝移植也一样涉及到内科和外科.     

Case Report: Delayed resolution of severe pulmonary hypertension after isolated liver transplantation in a patient with cirrhosis

Pulmonary hypertension is now recognized to be a rare association of liver disease and portal hypertension. This report describes the slow resolution of symptomatic pulmonary hypertension in a 33-year-old woman with cirrhosis who underwent isolated liver transplantation. The patient survived the surgery and perioperative period without significant haemodynamic compromise. After liver transplantation, the patient was monitored with regular Doppler echocardiography. By 27 months the pulmonary hypertension had almost completely resolved. This observation is important, as it suggests that patients with severe pulmonary hypertension who survive the perioperative period may have an excellent outcome, although resolution may be slow.