Sources and sequelae of bacterial contamination of hematopoietic stem cell components: implications for the safety of hematotherapy and graft engineering

Background: It is important to compare the incidence of bacterial contamination of components collected from the peripheral blood or bone marrow (BM), as well as of components processed with or without cell selection or depletion, and to evaluate the sequelae of such contamination. Study Design and Methods: Bacterial contamination rates were compared in 1380 untreated autologous peripheral blood progenitor cells (PBPCs), 291 untreated autologous BM samples, 916 monoclonal antibody (MoAb)-treated autologous and allogeneic BM samples, and in 45 autologous PBPC components from which the CD34+ cells were selected. Bacterial cultures were performed at sequential time points during the processing of MoAb-treated BM. Results: Bacterial contamination was documented in 44 of 2632 components from 1593 patients (1.67% of components, 2.76% of patients) before cryopreservation. Although only 0.65% of untreated PBPCs were contaminated before cryopreservation, each patient was more likely to have given a contaminated PBPC component than a contaminated BM component (2.41% vs. 0%, p < 0.01). Bacterial contamination of MoAb-treated BM was greater during or after manipulation than it was before (2.33% vs. 0.77%, p < 0.05). At thawing, contamination was documented in 42 (1.97%) of 2136 components cultured. Ten (13.7%) of 73 patients who received hematopoietic progenitor cells that were contaminated before cryopreservation or at thawing developed fever or positive blood cultures within 48 hours of transfusion. Fever was associated with bacteremia in two cases, but no irreversible clinical sequelae were noted. Conclusion: These studies suggest that, despite careful attention to sterile procedures, low-level contamination of hematopoietic stem cell components can be introduced before or during manipulation as well as at thawing, and that standards for monitoring of the procedures for collection, processing, cryopreservation, thawing, and transfusion of hematopoietic progenitor cells are necessary.     

Enhanced passive mixing for paper microfluidics

Imprecise control of fluid flows in paper-based devices is a major challenge in pushing the innovations in this area towards societal implementation. Assays on paper tend to have low reaction yield and reproducibility issues that lead to poor sensitivity and detection limits. Understanding and addressing these issues is key to improving the performance of paper-based devices. In this work, we use colorimetric analysis to observe the mixing behaviour of molecules from two parallel flow streams in unobstructed (on unpatterned paper) and constricted flow (through the gap of a patterned hourglass structure). The model system used for characterization of mixing involved the reaction of Fe³⁺ with SCN⁻ to form the coloured, soluble complex Fe(SCN)²⁺. At all tested concentrations (equal concentrations of 50.0 mM, 25.0 mM or 12.5 mM for KSCN and FeCl₃ in each experiment), the reaction yield increases (higher colorimetric signal) and better mixing is obtained (lower relative standard deviation) as the gap of the flow constriction becomes smaller (4.69–0.32 mm). This indicates enhanced passive mixing of reagents. A transition window of gap widths exhibiting no mixing enhancement (about 2 mm) to gap widths exhibiting complete mixing (0.5 mm) is defined. The implementation of gap sizes that are smaller than 0.5 mm (below the transition window) for passive mixing is suggested as a good strategy to obtain complete mixing and reproducible reaction yields on paper. In addition, the hourglass structure was used to define the ratio of reagents to be mixed (2 : 1, 1 : 1 and 1 : 2 HCl–NaOH) by simply varying the width ratio of the input channels of the paper. This allows easy adaptation of the device to reaction stoichiometry.

Efficient passive mixing can be achieved by contricting the reagent flow using structures having narrow gaps.     

Need for recovery from work in relation to age: a prospective cohort study

Purpose  

To investigate the impact of increasing age on the need for recovery (NFR) over time among day workers     

组成型αB晶体蛋白在热休克蛋白核转录因子1敲除小鼠心肌中的表达

目的:了解热休克蛋白核转录因子1(HSF1)对小鼠心肌组成型αB晶体蛋白(αB-Crystallin,αBC)表达的影响.方法:用western blot和免疫组织化学的方法,测定组成型αBC在HSF1基因野生型(hsf1+/+)和HSF1基因敲除型(hsf1-/-)小鼠心肌中的表达.结果:αBC在hsf1-/-和hsf1+/+小鼠心肌表达量分别为68.42±4.16和100.00±7.58(心肌可溶性组分,P＜0.05),20.35±1.01和37.55±1.91(心肌不可溶性组分,P＜0.05);免疫组化显示αBC在hsf1-/-心肌细胞内的表达信号较hsf1+/+明显减弱.结论:HSF1基因是介导组成型αBC基因表达重要的、但不是惟一的因子.     

丹参通络解毒汤联合内皮祖细胞移植对心肌缺血再灌注损伤大鼠促血管新生作用的研究

目的探讨丹参通络解毒汤(DSTLJD)联合内皮祖细胞(endothelial progenitor cells, EPCs)移植对心肌缺血再灌注损伤(ischemic reperfusion injury, IRI)模型大鼠促血管新生作用的影响及其机制。方法采用密度梯度离心法及差数贴壁法分离和培养EPCs,采用免疫荧光法鉴定EPCs。通过结扎左冠状动脉左前降支的方法建立IRI模型,采用随机数字表法分为SH组(假手术组)、IRI组(模型组)、EPCs组(EPCs移植组)、DSTLJD组(丹参通络解毒汤组)、DSTLJD+EPCs组(丹参通络解毒汤+EPCs移植),每组10只。4周后,采用HE染色法观察心肌组织的病理形态,用免疫组化法测定各组大鼠心肌微血管计数(microvessel count, MVC)、心肌微血管密度(microvessel density, MVD),并检测各组大鼠血管内皮生长因子(vascular endothelial growth factor, VEGF)、碱性成纤维生长因子(basic fibroblast growth factor, bFGF)的蛋白表...     

Effective treatment of painful bone crises in type I gaucher's disease with high dose prednisolone

In type I Gaucher's disease, episodes of severe disabling bone pain, the so called bone crises, may be resistant to all analgesics, including narcotics. The demonstration of subperiosteal oedema on magnetic resonance imaging (MRI) led to an attempt to use steroids to relieve the oedema and thereby the pain. On eight occasions, five patients with documented bone crises received conventional dose steroids (20 mg/m2/day) with considerable shortening of the attacks. On six occasions five further patients received high dose methylprednisolone (30 mg/kg intravenously or 1 g/m2 orally daily for two days), which was followed by oral prednisone for three to five days on the last four occasions. In this later group, pain relief was evident within several hours. Three treatments were given on an ambulatory basis. The MRI scan of one of these patients showed no subperiosteal fluid collection five days after high dose steroids had been started, and on subsequent x ray examination, there was no periosteal elevation. This treatment should be considered in cases of Gaucher's disease with bone crises.     

Keratoprosthesis results in animals: An update

Background: The report presented is an update on continuing development work on modified PHEMA core-and-shirt KPros in animals. Methods: Two variations (improved wet-eye, and dry-eye) of a prototype core-and-skirt Chirila KPro are described. The clinical success rate on implantation of these versions of the Chirila KPro was assessed. Results: It was found that a significant improvement in retention rate was shown in the improved model but that the dry-eye model failed early in two of the three implanted. Conclusions: The significance of the improved strength and the reasons for disappointing results with the early dry-eye KPros are discussed. Ongoing work is briefly outlined.     

Quantitation of apo-, mono-, and diferric transferrin by polyacrylamide gradient gel electrophoresis in patients with disorders of iron metabolism

We have developed a polyacrylamide gradient gel electrophoretic method to quantitate apo-, mono-, and diferric transferrin based upon differences in their molecular size. Purified transferrin saturated to different extents (3% to 98%) with iron showed proportions of the three forms as predicted from an approximately random distribution of iron between the two metal-binding sites. The iron distributions in sera of 14 normal individuals similarly correlated with the predicted values. In contrast, 22 of 43 patients with diseases associated with abnormalities in iron or transferrin metabolism had a disproportionate increase in monoferric transferrin. This abnormality occurred in seven of nine patients who had received bone marrow transplants, seven of 14 with chronic liver disease, and eight of nine menstruating women with probable iron deficiency anemia. Interestingly, 11 patients with malabsorption or chronic renal disease had normal iron distributions. The finding of abnormal distributions of iron on transferrin suggests that gradient gel analysis may be a useful tool for studying the physiologic mechanisms controlling iron utilization.     

Absolute ethanol injection of the adrenal artery: hypertensive reaction

Transcatheter injection of 0.4 ml of absolute ethanol into the adrenal artery was performed in three Rhesus monkeys. The injection produced a mean increase of 60 mmHg in systolic blood pressure and 50 mmHg in diastolic blood pressure within two minutes. Hypertension was accompanied by cardiac arrhythmias (two monkeys) and sinus tachycardia (one monkey). These changes were probably related to an acute catecholamine release. Embolization of the inferior phrenic artery with Gelfoam powder produced only a mild blood pressure elevation in three monkeys (6 mmHg systolic pressure and 10 mmHg diastolic pressure).