Development of large numbers of mast cells at sites of idiopathic chronic dermatitis in genetically mast cell-deficient WBB6F1-W/Wv mice

The normal skin and other tissues of adult mast cell-deficient WBB6F1- W/Wv or WCB6F1-Sl/Sld mice contain less than 1.0% the number of mast cells present in the corresponding tissues of the congenic normal (+/+) mice. As a result, genetically mast cell-deficient WBB6F1-W/Wv or WCB6F1-Sl/Sld mice are widely used for studies of mast cell differentiation and function. We found that mast cells developed at sites of idiopathic chronic dermatitis in WBB6F1-W/Wv mice and that the number of mast cells present in the skin of WBB6F1-W/Wv mice was proportional to the severity of the dermatitis (in ear skin, there were 33 +/- 4 mast cells/mm2 of dermis at sites of severe dermatitis v 9 +/- 3 at sites of mild dermatitis, 0.8 +/- 0.3 in skin without dermatitis, and 100 +/- 7 in the normal skin of congenic WBB6F1-+/+ mice; in back skin, the corresponding values were 2.0 +/- 0.6, 1.1 +/- 0.9, 0.025 +/- 0.025, and 26.2 +/- 3.2). The development of mast cells was a local, not systemic, consequence of the dermatitis. Thus, WBB6F1-W/Wv mice with severe dermatitis lacked mast cells in skin not showing signs of dermatitis and also in the peritoneal cavity, stomach, cecum, and tongue. Idiopathic chronic dermatitis was not associated with the local development of mast cells in WCB6F1-Sl/Sld mice, a mutant whose mast cell deficiency is due to a mechanism distinct from that of WBB6F1-W/Wv mice. These findings may have implications for understanding the nature of the mast cell deficiency in WBB6F1-W/Wv and WCB6F1-Sl/Sld mice and for the use of these mutants to analyze mast cell differentiation and function.     

Physiologic regulation and tissue localization of renal erythropoietin messenger RNA

Although erythropoietin (Epo) is produced primarily by the kidneys in response to hypoxia, the precise cell type(s) and mechanisms by which these cells regulate production are poorly understood. In the experiments we report, the kinetics of renal Epo production in response to acute hypoxia and the intrarenal localization of cellular Epo synthesis were studied at the level of Epo mRNA. Erythropoietin mRNA expression was determined by Northern blot analysis of rat kidney RNAs using a probe derived from the mouse Epo gene. Renal Epo mRNA content increased as early as 1 hour after initiation of hypoxia and continued to accumulate during 4 hours of stimulation. Discontinuation of the hypoxic stimulus resulted in rapid decay of mRNA levels. Kidney and plasma Epo levels measured by radioimmunoassay paralleled, with respective lag times, the changes in renal Epo mRNA content, suggesting that Epo production in response to acute hypoxia represents de novo synthesis and is regulated by changes in Epo mRNA. Northern blot analysis of RNAs extracted from separated glomerular and tubular tissue fractions revealed Epo mRNA in the tubular fraction, whereas glomerular tissue did not contain Epo mRNA. Thus, the site of cellular Epo synthesis is located in the renal tubule or its interstitium and not in the glomerular tuft.     

Bone marrow transplantation for patients with Philadelphia chromosome- positive acute lymphoblastic leukemia

We report the treatment outcome of allogeneic bone marrow transplantation in ten patients with Philadelphia chromosome-positive acute lymphoblastic leukemia. Six patients are alive and well for 6 to 30 months (median 19 months) after transplantation. Four patients died with transplant related complications. In view of the poor prognosis associated with this disease, marrow ablation followed by allogeneic or syngeneic marrow grafting may be the preferred treatment modality if a suitable marrow donor is available.     

Evaluation of an automated microbiologic blood culture device for detection of bacteria in platelet components

BACKGROUND: Automated culture methods have been used by several investigators to detect bacterial contamination of cellular blood components. We investigated several factors affecting detection by automated culture of bacteria in platelet concentrates (PCs).These factors included the initial contamination level in PCs, the PC sample volume, the PC sample time, and the white cell level in relation to bacteria levels in the PCs. STUDY DESIGN AND METHODS: Staphylococcus epidermidis or Escherichia coli was inoculated into freshly prepared PCs or white cell-reduced PCs to yield colony-forming unit (CFU) levels of 10, 1, or 0.1 per mL. At the time of inoculation (t=0) and at t=6, t=24, and t=48 hours, 0.5, 1.0, and 2.0 mL samples of the contaminated PCs were transferred into culture bottles. The presence of bacteria in the culture bottles was subsequently monitored by an automated blood culturing instrument. Bacteria levels in the PC at the time of first automated culture detection were determined by quantitative plating. RESULTS: E. coli was detected in 92 percent of experiments when 1.0- or 2.0-mL samples were taken at t=6 hours. At t=24 hours, 100-percent detection was observed with all tested inoculation volumes; however, by that time,>10(7) CFU per mL of bacteria were present in every PC. For S. epidermidis, 89 percent and 83 percent of contaminated PCs were detected with a t=24 hour sampling time and 2.0- or 1.0-mL sampling volume. Seven of 36 PCs with a 2.0-mL sampling volume and 10 of 36 PCs with a 1.0-mL sampling volume contained>10(6) CFU per mL of S. epidermidis at the time of first detection. CONCLUSION: Data from this preliminary evaluation suggest that sampling times of 24 hours or more would be necessary to provide confidence in detection of E. coli or S. epidermidis in PCs using this culture method.     

Vascular smooth muscle cell-derived adiponectin: a paracrine regulator of contractile phenotype

Adiponectin is a cardioprotective adipokine derived predominantly from visceral fat. We recently demonstrated that exogenous adiponectin induces vascular smooth muscle cell (VSMC) differentiation via repression of mTORC1 and FoxO4. Here we report for the first time that VSMC express and secrete adiponectin, which acts in an autocrine and paracrine manner to regulate VSMC contractile phenotype. Adiponectin was found to be expressed in human coronary artery and mouse aortic VSMC. Importantly, siRNA knock-down of endogenous adiponectin in VSMC significantly reduced the expression of VSMC contractile proteins. Contractile protein deficiency was also observed in primary VSMC isolated from Adiponectin(-/-) mice. This deficiency could be rescued by culturing Adiponectin(-/-) VSMC in conditioned media from wild type (WT) VSMC. Moreover, the paracrine effect of VSMC-derived adiponectin was confirmed as adiponectin neutralizing antibody blocked the rescue. Overexpressed adiponectin also exerted paracrine effects on neighboring untransfected VSMC, which was also blocked by adiponectin neutralizing antibody. Interestingly, adiponectin expression was inducible by the PPARγ agonist rosiglitazone. Our data support an important role for VSMC-derived adiponectin in maintaining VSMC contractile phenotype, contributing to critical cardioprotective functions in the vascular wall. This article is part of a Special Issue entitled "Local Signaling in Myocytes".     

Manipulation of liver regeneration with macrophages to influence the hepatic progenitor cell niche

Insufficient regeneration of the adult liver is believed to cause failure to recover from severe liver disease. An undifferentiated cell population with stem-cell-like qualities known as hepatic progenitor cells (HPCs) is hypothesised to have a central role in regeneration of the adult liver during massive or chronic liver disease. Stem cells in other organ systems are believed to reside in a specialised microenvironment or niche that supports their maintenance and function. The existence of a hepatic stem cell niche might provide a means of therapeutically manipulating endogenous HPCs in vivo as a regenerative therapy.To investigate the physiological potential of HPCs to regenerate the mammalian liver, we have established a novel model of hepatocellular injury and HPC activation using genetic manipulation of hepatocytes. After hepatocyte senescence and death in this model (AhCre Mdm2^flox), HPCs expand and bring about the complete regeneration of the liver parenchyma.We demonstrate that a stereotypical niche, consisting partly of macrophages, exists in both animal models and correlating human disease. Using cell tracking, we show active recruitment of extrahepatic macrophages into this niche during injury. In health, intravenous injection of macrophages results in macrophage engraftment to the liver niche, with subsequent HPC activation and changes to liver structure and function.Within the niche, macrophages use paracrine signalling to control both HPC proliferation and cell fate via TWEAK (tumour-necrosis-factor-like weak inducer of apoptosis) and the Wnt signalling pathway, respectively. After hepatocellular injury, macrophages ingest hepatocyte debris, and release Wnt which promotes HPC differentiation into hepatocytes. TWEAK is vital for HPC proliferation in the AhCre Mdm2^flox model of regeneration. Here, the absence of TWEAK signalling results in liver failure and mortality.This work has demonstrated for the first time the ability of a solid organ to fully regenerate in the adult mammal from progenitor cells, and additionally highlights mechanisms by which this process can be modulated by either small molecule or cell therapy.FundingUniversity of Edinburgh.     

Effectiveness of methyl-GAG (methylglyoxal-bis[guanylhydrazone]) in patients with advanced malignant lymphoma

We treated 51 patients with advanced malignant lymphoma refractory to conventional therapy with methyl-glyoxal-bis(guanylhydrazone) (methyl- GAG) at doses ranging from 400 to 800 mg/sq m. Therapy was started on a weekly schedule and was switched to every other week in responding patients at the onset of toxicity. Partial responses were observed in 6 of 13 evaluable patients with Hodgkin's disease (46%), 5 of 10 patients with diffuse poorly differentiated lymphocytic lymphoma (50%), 2 of 4 patients with nodular poorly differentiated lymphocytic lymphoma (50%), and 3 of 13 patients with diffuse histiocytic lymphoma (23%). Two of six patients with mycosis fungoides showed objective improvement in cutaneous disease. Toxicity was generally mild and included muscular weakness, myalgia, mucositis, and diarrhea; two patients developed bronchospasm following drug infusions. We conclude that methyl-GAG has major antitumor activity when administered on this schedule to patients with advanced malignant lymphoma. The low degree of toxicity, unique mechanism of action, and minimal myelosuppressive effects suggest that methyl-GAG will prove useful in future trials of combination chemotherapy regimens for the treatment of lymphoma.     

Functional entrapment of the popliteal artery

A case of functional entrapment missed at the initial angiogram is presented. The imaging of popliteal artery entrapment syndrome and functional entrapment is discussed. The importance of appropriate imaging is emphasized. The classification of popliteal artery entrapment syndrome is discussed and it is proposed that functional entrapment is added to the existing classification in the interest of consistent reporting.     

角膜缘干细胞移植在眼科的临床应用及发展

目的:探讨角膜缘干细胞移植的应用现状及发展前景。资料来源:应用计算机检索PUBMED 2000/2007与角膜缘干细胞移植相关的文章,检索词“limbal stem cells,transplantation”,限定文献语种为“English”;同时检索万方数据库2000/2007相关文章,检索词“角膜缘干细胞,移植”,限定文献语种为中文。资料选择:共检索到相关文献180余条,选择与角膜缘干细胞的组织生物学特征、角膜缘干细胞的体外培养以及角膜缘干细胞的临床应用相关的文章。资料提炼:将初步筛选的文章进一步查找全文,排除综述和重复文献,内容相似的选择发表在权威杂志或近3年发表的文献,无论有无对照组,观察对象为人或动物均纳入。最后共纳入37篇进行综述,其中7篇研究角膜缘干细胞的组织生物学特性,8篇介绍角膜缘干细胞的体外培养,剩余22篇文章为角膜缘干细胞移植的基础和临床研究。资料综合:角膜缘干细胞移植,可以恢复正常的角膜缘屏障功能,重建眼表的完整性;而最终改善角膜的透明性和视功能。目前开展的角膜缘干细胞移植,包括自体或异体角膜缘组织移植和体外培养的角膜缘干细胞移植。自体角膜缘干细胞的移植已成为临床上较为可靠和日益成熟的治疗方法,但来源有限,且不适合双眼角膜缘病变的患者,异体角膜缘组织移植存在排斥反应,因此自体角膜缘干细胞体外培养移植术被认为是目前较理想的角膜缘干细胞移植方法,但其远期疗效需进一步临床观察。结论:目前角膜缘干细胞移植治疗严重角膜病变的研究尚处于初步阶段,自体角膜缘干细胞移植成功率是较高,自体角膜缘干细胞培养后移植治疗眼表疾病已初步获得成功,但还存在一些问题,如角膜缘干细胞生存的微环境、培养的干细胞生理、生化的免疫特性,以及黏附、增殖、分化能力等问题尚需进一步研究。