Adipose-derived stromal vascular fraction improves tendon healing in rabbits

Objective:To evaluate the potential effects of uncultured adipose-derived stromal vascular fraction on tendon healing.Methods:Twenty five adult male New Zealand white rabbits weighing 2.5-3.0 kg were used.Five rabbits were used as donors of adipose tissue and the rest were divided into control and treatment groups.The injury model was completed by unilateral tenotomy through the middle one third of deep digital flexor tendon.Immediately after suture repair,either fresh stromal vascular fraction from enzymatic digestion of adipose tissue or placebo was intratendinously injected at tendon stumps in treatment and control groups,respectively.Immobilization with cast was continued for two weeks after surgery.Animals were sacrificed at eight weeks after surgery and tendons underwent histological,immunohistochemical,and mechanical evaluations.Statistical analyses of quantitative and qualitative data were assessed using one-way analysis of variance and MannWhitney U-test,respectively.Results:Histological evaluations demonstrated superior fibrillar linearity and continuity,and decreased vascularity in treatment group indicated improved organization and remodeling of neotendons.Immunohistochemistry demonstrated a significant increase in collagen I expression in treatment group.Ultimate load and energy absorption capacity were both significantly increased in cell-treated repairs compared with controls.Conclusion: The present study shows that intratendinous injection of uncultured adipose-derived stromal vascular fraction results in improved structural and mechanical properties of tendon repairs and it could be an effective modality for treating tendon injury.     

Suppression of leukemia development caused by PTEN loss

Multiple genetic or molecular alterations are known to be associated with cancer stem cell formation and cancer development. Targeting such alterations, therefore, may lead to cancer prevention. By crossing our previously established phosphatase and tensin homolog (Pten)-null acute T-lymphoblastic leukemia (T-ALL) model onto the recombination-activating gene 1(-/-) background, we show that the lack of variable, diversity and joining [V(D)J] recombination completely abolishes the Tcrα/δ-c-myc translocation and T-ALL development, regardless of β-catenin activation. We identify mammalian target of rapamycin (mTOR) as a regulator of β-selection. Rapamycin, an mTOR-specific inhibitor, alters nutrient sensing and blocks T-cell differentiation from CD4(-)CD8(-) to CD4(+)CD8(+), the stage where the Tcrα/δ-c-myc translocation occurs. Long-term rapamycin treatment of preleukemic Pten-null mice prevents Tcrα/δ-c-myc translocation and leukemia stem cell (LSC) formation, and it halts T-ALL development. However, rapamycin alone fails to inhibit mTOR signaling in the c-Kit(mid)CD3(+)Lin(-) population enriched for LSCs and eliminate these cells. Our results support the idea that preventing LSC formation and selectively targeting LSCs are promising approaches for antileukemia therapies.     

Efficient Dielectrophoretic Patterning of Embryonic Stem Cells in Energy Landscapes Defined by Hydrogel Geometries

In this study, we have developed an integrated microfluidic platform for actively patterning mammalian cells, where poly(ethylene glycol) (PEG) hydrogels play two important roles as a non-fouling layer and a dielectric structure. The developed system has an embedded array of PEG microwells fabricated on a planar indium tin oxide (ITO) electrode. Due to its dielectric properties, the PEG microwells define electrical energy landscapes, effectively forming positive dielectrophoresis (DEP) traps in a low-conductivity environment. Distribution of DEP forces on a model cell was first estimated by computationally solving quasi-electrostatic Maxwell’s equations, followed by an experimental demonstration of cell and particle patterning without an external flow. Furthermore, efficient patterning of mouse embryonic stem (mES) cells was successfully achieved in combination with an external flow. With a seeding density of 10⁷ cells/mL and a flow rate of 3 μL/min, trapping of cells in the microwells was completed in tens of seconds after initiation of the DEP operation. Captured cells subsequently formed viable and homogeneous monolayer patterns. This simple approach could provide an efficient strategy for fabricating various cell microarrays for applications such as cell-based biosensors, drug discovery, and cell microenvironment studies.     

A Novel Heterophilic Antibody Interaction Involves IgG4

IgG4 has been implicated in a diverse set of complex pathologies – e.g. autoimmune pancreatitis (AIP), idiopathic membranous nephropathy – and carries unique features including lack of activation of the classical complement pathway and a dynamic Fab‐arm exchange. We recently showed that the rheumatoid factor (RF)‐like activity of IgG4 is achieved through a hitherto unknown, Fc–Fc (and not Fab–Fc as is the case in classical RF; CRF) interaction; hence the name, novel RF (NRF). Here, we further explore the resemblance/difference between CRF and NRF. As heterophilic interactions of human IgM RF (CRF) are well known, we checked whether this is the case for IgG4. Human IgG4 showed variable reactivity to animal IgGs: reacting intensely with rabbit and mouse IgGs, but weakly with others. The binding to rabbit IgG was not through the Fab (as in CRF) but via the Fc piece, as was recently shown for human IgG (NRF). This binding correlates with the IgG4 concentration per se and could therefore be of diagnostic usage and incidentally explain some observed interferences in biological assays. In conclusion, here is defined a novel heterophilic antibody interaction and is established the universality of the unique Fc–Fc binding, both involving IgG4.     

Triple non-invasive diagnostic test for exclusion of common bile ducts stones before laparoscopic cholecystectomy

AIM： To evaluate the impact of a preoperative ＂triple non-invasive diagnostic test＂ for diagnosis and/or exclusion of common bile duct stones. METHODS： All patients with symptomatic gallstone disease, operated on by laparoscopic cholecystectomy from March 2004 to March 2006 were studied retrospectively. Two hundred patients were included and reviewed by using a triple diagnostic test including： patient＇s medical history, routine liver function tests and routine ultrasonography. All patients were followed up 2-24 mo after surgery to evaluate the impact of triple diagnostic test. RESULTS： Twenty-five patients were identified to have common bile duct stones. Lack of history of stones, negative laboratory tests and normal ultrasonography alone was proven to exclude common bile duct stones in some patients. However, a combination of these three components （triple diagnostic）, was proven to be the most statistically significant test to exclude common bile duct stones in patients with gallstone disease. CONCLUSION： Using a combination of routinely used diagnostic components as triple diagnostic modality would increase the diagnostic accuracy of common bile duct stones preoperatively. This triple non-invasive test is recommended for excluding common bile duct stones and to identify patients in need for other investigations.     

Preconditioning with oxygen attenuates rat renal ischemia-reperfusion injury

BACKGROUND: Short time pretreatment with oxygen is reported to be protective against subsequent ischemia-reperfusion (IR) injury of heart and spinal cord in some animal models. The purpose of this study was to investigate the effects of pre-exposure to hyperoxic environment on rat renal IR injury for the first time. MATERIALS AND METHODS: The effects of 1 h/d pretreatment with oxygen (>or=95%) for 5 days on a right nephrectomized rat model of renal IR injury was investigated by comparing creatinine clearance, fractional excretion of sodium, plasma creatinine, blood urea nitrogen, and histological injury scores among three groups: IR (40 min ischemia-24 h reperfusion), sham (no IR), and hyperoxia (5 days intermittent pretreatment with oxygen + IR). RESULTS: Intermittent pretreatment with oxygen resulted in significant improvement of creatine clearance and fractional excretion of sodium (P 相似文献   

The effects of fructo-oligosaccharides in combination with soy protein on bone in osteopenic ovariectomized rats

OBJECTIVE: The intestinal microflora is important in rendering soy isoflavones bioavailable by facilitating their conversion to equol. Hence, substances that can modulate the intestinal microflora could affect the bioavailability of isoflavones. In this study, we examined the effects of fructo-oligosaccharides (FOS), a prebiotic, on enhancing the effects of soy isoflavones on bone in ovariectomized osteopenic female rats. DESIGN: Sixty-three 9-month-old female Sprague-Dawley rats were either sham-operated (Sham; one group) or ovariectomized (Ovx; four groups) and were fed a control diet for 3 months to induce bone loss. After bone loss was confirmed via dual-energy x-ray absorptiometry, rats were placed on dietary treatment for 4 months. The Sham and one Ovx group received a control diet, and the remaining Ovx groups received either a soy protein-based diet (Soy), a FOS-supplemented diet (FOS), or a soy protein-based and FOS-supplemented diet (Soy+FOS). Before the termination of the study, whole-body bone mineral density (BMD) and bone mineral content (BMC) were assessed under anesthesia. Immediately after euthanasia, bone specimens were collected for the assessments of BMD, BMC, and biomechanical and microarchitectural properties. RESULTS: Whole-body BMD values were significantly higher in FOS and Soy+FOS groups compared with Ovx controls. The tibial BMC increased by 10%, 6%, and 4% in Soy, FOS, and Soy+FOS groups, respectively, compared to the Ovx control group. FOS and FOS+Soy treatments had the most pronounced effects in enhancing lumbar BMC and BMD. The FOS+Soy combination effectively improved tibial microarchitectural properties by enhancing trabecular number and lowering trabecular separation compared with Ovx controls. The effects of dietary treatments on lumbar microarchitectural properties were minimal and biomechanical properties of the femur were not affected by any of the dietary treatments. CONCLUSION: Our findings suggest that, although incorporation of either soy or FOS in the diet of Ovx rats can improve BMD of the whole body, tibiae, and lumbar vertebrae, their combination had no any additive effects. However, in terms of microarchitecture, the combination of soy and FOS had a greater effect in reversing the loss of certain microarchitectural parameters such as tibial trabecular number, separation, and thickness.     

Genetics of type 2 diabetes mellitus and obesity--a review

Type 2 diabetes (T2D) and obesity are recognized as conditions of growing biomedical importance to societies worldwide. Despite this, lack of understanding concerning the processes which normally serve to maintain weight and to regulate glucose concentrations, and ignorance about the mechanisms by which these homeostatic processes fail, remains a significant obstacle to the development of improved tools for management and prevention. There has been a long-standing belief that the identification of the specific genes influencing development of these conditions has the potential to reveal these fundamental processes, thereby providing vital clues to support clinical advances. Furthermore, there has been the hope that this information will translate into the capacity to deliver more 'personalized' medical care, whereby management can be tailored in accordance with an appreciation of individual molecular pathogenesis. As this review indicates, these developments are already a reality for selected monogenic forms of diabetes and obesity. Recent advances in the identification of genes underlying multifactorial forms of these conditions will accelerate efforts to effect similar clinical translation across the full spectrum of disease.