Direct acute tubular damage contributes to Shigatoxin‐mediated kidney failure

The pathogenesis and therapy of Shigatoxin 2 (Stx2)‐mediated kidney failure remain controversial. Our aim was to test whether, during an infection with Stx2‐producing E. coli (STEC), Stx2 exerts direct effects on renal tubular epithelium and thereby possibly contributes to acute renal failure. Mice represent a suitable model because they, like humans, express the Stx2‐receptor Gb3 in the tubular epithelium but, in contrast to humans, not in glomerular endothelia, and are thus free of glomerular thrombotic microangiopathy (TMA). In wild‐type mice, Stx2 caused acute tubular dysfunction with consequent electrolyte disturbance, which was most likely the cause of death. Tubule‐specific depletion of Gb3 protected the mice from acute renal failure. In vitro, Stx2 induced secretion of proinflammatory cytokines and apoptosis in human tubular epithelial cells, thus implicating a direct effect of Stx2 on the tubular epithelium. To correlate these results to human disease, kidney biopsies and outcome were analysed in patients with Stx2‐associated kidney failure (n = 11, aged 22–44 years). The majority of kidney biopsies showed different stages of an ongoing TMA; however, no glomerular complement activation could be demonstrated. All biopsies, including those without TMA, showed severe acute tubular damage. Due to these findings, patients were treated with supportive therapy without complement‐inhibiting antibodies (eculizumab) or immunoadsorption. Despite the severity of the initial disease [creatinine 6.34 (1.31–17.60) mg/dl, lactate dehydrogenase 1944 (753–2792) U/l, platelets 33 (19–124)/nl and haemoglobin 6.2 (5.2–7.8) g/dl; median (range)], all patients were discharged after 33 (range 19–43) days with no neurological symptoms and no dialysis requirement [creatinine 1.39 (range 0.84–2.86) mg/dl]. The creatinine decreased further to 0.90 (range 0.66–1.27) mg/dl after 24 months. Based on these data, one may surmise that acute tubular damage represents a separate pathophysiological mechanism, importantly contributing to Stx2‐mediated acute kidney failure. Specifically in young adults, an excellent outcome can be achieved by supportive therapy only. © 2014 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.     

利拉鲁肽诱导骨髓间充质干细胞定向分化及移植治疗1型糖尿病大鼠的研究

目的 体外研究利拉鲁肽诱导骨髓间充质干细胞（BM-MSCs）分化为胰岛素分泌细胞（IPCs）,并在体内进一步观察IPCs移植对1型糖尿病（T1DM）大鼠的治疗作用.方法 （1）体外采用密度梯度离心联合差壁培养法分离、纯化大鼠BM-MSCs,进一步分为未诱导组、高糖＋尼克酰胺诱导组、胰高血糖素样肽1（GLP-1）诱导组和利拉鲁肽诱导组;（2）倒置显微镜下观察各组细胞形态变化,双硫腙染色鉴定诱导后细胞,荧光定量PCR检测巢蛋白（Nestin）、胰十二指肠同源盒1（PDX-1）、葡萄糖转运蛋白2（Glut-2）、葡萄糖激酶（GK）、胰岛素和胰高血糖素等基因,细胞免疫荧光检测胰岛素和胰高血糖素等蛋白;（3）将180 ～ 220 g的30只雄性SD大鼠以60 mg/kg剂量腹腔注射链脲佐菌素制备T1DM模型,造模成功后按随机数字表法分为对照组（T1DM组,n=8）、未诱导的BM-MSCs移植组（BM-MSCs组,n=9）和经利拉鲁肽诱导的BM-MSCs移植组（LIRA＋ BM-MSCs组,n=9）,给予相应干预8周,待血糖基本稳定后,选取4只正常、同龄、雄性SD大鼠作为对照,行腹腔注射的葡萄糖耐量试验（IPGTT）进一步观察移植后细胞对高糖刺激的反应性.结果 （1）利拉鲁肽诱导后BM-MSCs形态逐渐变圆,呈明显的聚集性生长状态,双硫腙染色为阳性;与高糖＋尼克酰胺诱导组比较,利拉鲁肽诱导组细胞Nestin mRNA表达下调（0.003 8±0.000 4比0.007 5±0.003 0,P＜0.05）,胰岛素（0.000 20±0.000 03比0.000 08±0.000 02）和胰高血糖素（0.001 1±0.0004比0.000 7±0.000 1）等mRNA表达上调（F=7.26、10.06、4.92,均P＜0.05）,PDX-1、Glut-2、GK mRNA表达亦上调;利拉鲁肽诱导组和GLP-1诱导组细胞胰岛素或胰高血糖素蛋白表达均呈阳性.（2）体内实验示,与T1DM组比较,LIRA＋ BM-MSCs组和BM-MSCs组大鼠8周末血糖均明显降低[分别为（28.0±1.2）、（8.9±1.1）、（14.5±0.9）mmol/L,F=719.61,均P＜0.05];IPGTT提示移植IPCs后的大鼠血糖在30 min时升至峰值,150 min时降至空腹水平,血糖变化曲线与正常组类似.结论 体外利拉鲁肽可以在一定程度上促进BM-MSCs分化成为IPCs,且移植后的IPCs能够在体内进一步发挥降糖作用.     

利拉鲁肽在人骨髓间充质干细胞诱导分化为胰岛素分泌细胞中的作用

目的 观察利拉鲁肽在入骨髓间充质干细胞( hBM-MSCs)向胰岛素分泌细胞(IPCs)方向分化诱导中的作用.方法 采用高糖、尼克酰胺和利拉鲁肽3阶段诱导方案对hBM-MSCs进行定向诱导分化,倒置显微镜下观察诱导过程中细胞的形态学变化,双硫腙染色法鉴定诱导后细胞,Western印迹法检测细胞胰腺十二指肠同源盒基因1( PDX-1)、葡萄糖转运蛋白2(GLUT2)、葡萄糖激酶(GK)、胰岛素的蛋白表达,ELISA检测细胞的胰岛素分泌水平.结果 添加10 nmol/L利拉鲁肽作用7d后诱导效率明显增加.诱导过程中细胞形态由长梭形逐渐变为圆形,并聚集生长,至诱导末出现大量圆形葡萄状聚集生长的胰岛样细胞团;双硫腙染色阳性细胞量、细胞PDX-1、GLUT2、GK、胰岛素的蛋白表达、细胞的基础和葡萄糖刺激的胰岛素分泌水平均逐渐增加(均P＜0.05).结论 在体外,高糖、尼克酰胺联合利拉鲁肽可使hBM -MSCs定向诱导分化为IPCs.     

梅花的本草考证

梅花为我国传统药材,具有疏肝和中,化痰散结的作用,常用于治疗梅核气,肝胃气痛,食欲不振,头晕,瘰疬。梅原产中国,其栽培应用历史悠久,品种复杂繁多,现代研究将梅分为果梅与花梅两类,品种达数百个之多。但关于古代文献中统究竟以何种颜色梅花入药为佳,以及药用梅花类群与植物系统学的关联性等尚未有相关的研究报道。为正本清源,笔者对历代本草中梅花的基原、品质与产地变迁进行了考证,发现传统的药用梅花主要为绿萼梅和白梅花,并得出药用梅花来自真梅系花梅,其中绿萼梅属于绿萼品种群,药用白梅花则对应玉蝶品种群及单瓣品种群的结论。梅的产地最早记载于《神农本草经》“生汉中川谷”,即今陕西南部地区。宋代之后,由于气候及社会经济等因素,梅的产地从陕西不断南移至长江、洞庭湖区域;至明清时期,广东、海南地区也有梅的分布的报道。至近现代,受自然气候条件变化及城镇化等因素综合影响,药用梅花的产区已由四川及江浙一带,逐步变迁至目前的安徽皖南地区。该文对药用梅花的基原考证及产地变迁进行了系统的梳理,可为梅花的正本清源、药用梅花类群的明确和其进一步资源开发利用等提供参考依据。     

Spread of extended-spectrum β-lactamase genes of bla OXA-10, bla PER-1 and bla CTX-M in Pseudomonas aeruginosa strains isolated from burn patients

BackgroundPseudomonas aeruginosa is resistant to many antibiotics due to production of different classes of extended spectrum β-lactamases (ESBLs). Prevalence of ESBLs among P. aeruginosa has been increased in recent years, demonstrate a serious health problem especially in burn units worldwide.ObjectivePresent study was designed to determine the ESBL producing strains and identify the genes encoding three different ESBLs of bla PER-1, bla OXA-10 and bla CTX-M genes in P. aeruginosa isolates from burn patients.MethodsIn total 185 clinical isolates of P. aeruginosa were collected from infectious wounds of hospitalized burn patients. Antimicrobial susceptibility testing and phenotypic detection of ESBL were performed by disk diffusion method and Double disk Synergy Test (DDST). Polymerase Chain Reaction (PCR) was done for detection of bla OXA-10, bla PER-1 and bla CTX-M ESBL encoding genes.ResultsIn total, 176 (95.13%) isolates were multidrug resistant. The DDST demonstrated 96 (51.9%) isolates as putative ESBL producers with 100% or highly resistance to ofloxacin, cephalexin, aztreonam (97.57%) and ceftriaxone (91.6%). By PCR amplification, bla PER-1, bla OXA-10 and bla CTX-M genes were detected in 52 (54.16%), 66 (68.75%) and 1 (1.04%) isolates of ESBL producers respectively. Forty-three isolates (44.79%) were simultaneously positive for both bla OXA-10 and bla PER-1 related genes.ConclusionThe rate of ESBL producing P. aeruginosa was notable in present study. Since there are only limited effective antibiotics against the bacterium, therefore all isolates must be investigated by antimicrobial susceptibility testing, which limits resistance development in burn units and helps the management of treatment strategy.     

Raw Milk Consumption among Patients with Non–Outbreak-related Enteric Infections,Minnesota, USA, 2001–2010

Raw milk has frequently been identified as the source of foodborne illness outbreaks; however, the number of illnesses ascertained as part of documented outbreaks likely represents a small proportion of the actual number of illnesses associated with this food product. Analysis of routine surveillance data involving illnesses caused by enteric pathogens that were reportable in Minnesota during 2001–2010 revealed that 3.7% of patients with sporadic, domestically acquired enteric infections had reported raw milk consumption during their exposure period. Children were disproportionately affected, and 76% of those <5 years of age were served raw milk from their own or a relative’s farm. Severe illness was noted, including hemolytic uremic syndrome among 21% of Escherichia coli O157–infected patients reporting raw milk consumption, and 1 death was reported. Raw milk consumers, potential consumers, and policy makers who might consider relaxing regulations regarding raw milk sales should be educated regarding illnesses associated with raw milk consumption.     

Outcome of Endoscopic Transsphenoidal Surgery in Combination with Somatostatin Analogues in Patients with Growth Hormone Producing Pituitary Adenoma

Objective

To determine the efficacy of endoscopic surgery in combination with long-acting somatostatin analogues (SSAs) in treating patients with growth hormone (GH)-secreting pituitary tumor.

Methods

We performed retrospective analysis of 133 patients with GH producing pituitary adenoma who underwent pure endoscopic transsphenoidal surgery in our center from January 2007 to July 2012. Patients were followed up for a range of 3-48 months. The radiological remission, biochemical remission and complication were evaluated.

Results

A total of 110 (82.7%) patients achieved radiological complete resection, 11 (8.2%) subtotal resection, and 12 (9.0%) partial resection. Eighty-eight (66.2%) patients showed nadir GH level less than 1 ng/mL after oral glucose administration. No mortality or severe disability was observed during follow up. Preoperative long-acting SSA successfully improved left ventricle ejection fraction (LVEF) and blood glucose in three patients who subsequently underwent success operation. Long-acting SSA (20 mg every 30 days) achieved biochemical remission in 19 out 23 (82.6%) patients who showed persistent high GH level after surgery.

Conclusion

Endoscopic transsphenoidal surgery can biochemically cure the majority of GH producing pituitary adenoma. Post-operative use of SSA can improve biochemical remission.     

Glutamate receptors and the regulation of steroidogenesis in the human adrenal gland: The metabotropic pathway

Background

l-glutamate is a major excitatory neurotransmitter in the mammalian brain. Glutamate receptors have been reported in the rat adrenal cortex and in human aldosterone-producing adenomas (APA). However, details regarding the expression levels and functions of these receptors in human adrenocortical tissues remain unknown.

Methods

The mRNA levels of glutamate receptors were evaluated by qPCR in: 12 normal adrenal cortex (NAC), 11 APA, and 12 cortisol-producing adenoma (CPA) tissues. Protein localization was evaluated by immunohistochemistry for 15 NAC, 5 idiopathic hyperaldosteronism cases, 15 APA and 15 CPA. H295R cells were treated with angiotensin-II or forskolin alone or combined with the GRM2/3 agonist LY354740.

Results

The level of GRM3 mRNA was higher in APA than in CPA (P = 0.0086) or NAC (P = 0.0022). GRM1, IGLUR2, and IGLUR3 were also detected in adrenocortical tissues. When added to angiotensin-II/forskolin treatments, LY354740 decreased aldosterone and cortisol production in H295R cells.

Conclusions

GRM3 is considered to regulate steroidogenesis in adrenocortical tissues.     

Enterobacteriaceae bacteremia: Risk factors for ESBLPE

Objectives

The increasing prevalence of extended spectrum beta-lactamase producing enterobacteriaceae (ESBLPE) requires defining the use of carbapenems in first intention. We analyzed the associations between enterobacteriaceae bacteremia (EbBact) and ESBLPE carriage during 10 years in a 950-bed teaching hospital.

Methods

We analyzed a 10-year (July 2001 to June 2011) prospective collection of bacteremia cases including 2 databases: (1) EbBact and (2) a computerized database of patients carrying EBLSE. Only one episode of EbBact was analyzed per patient and hospital stay. Factors associated with ESBLPE bacteremia were assessed by univariate and multivariate logistic regression analysis.

Results

Overall, 2355 cases of EbBact were identified, among which 135 (5.7%) were ESBLPE (2001–05: 1.4%, 2006–09: 7.6%, 2010–11: 14.2%). ESBLPE bacteremia was observed in 52 of the 88 (59%) patients carrying ESBLPE and in 83/2267 (3.7%) patients not known to be colonized with ESBLPE. Factors associated with ESBLPE bacteremia in patients not known to be colonized were: female gender (ORa = 0.56, CI95% [0.34–0.91]), hospitalization in the ICU (ORa = 2.51 [1.27–5.05]) or medical/surgical wards (ORa = 1.83 [1.04–3.38]), the period (2006–09, ORa = 4.08 [2.21–8.16]; 2010–11, ORa = 8.17 [4.14–17.06] compared to 2001–05), and history of EbBact (ORa = 2.29 [0.97–4.79]).

Conclusion

In case of EbBact, patients known to be colonized with ESBLPE present with ESBLPE bacteremia in more than half of the cases, requiring carbapenems as empirical antibiotic treatment. The global prevalence of ESBLPE among patients presenting with EbBact not known to be colonized with ESBLPE was 3.7%.