Expansion in vitro of retrovirally marked totipotent hematopoietic stem cells

A large number of biologic, technological, and clinical studies await the development of procedures that will allow totipotent hematopoietic stem cells to be expanded in vitro. Previous work has suggested that hematopoiesis can be reconstituted using transplants of cells from long- term marrow cultures. We have used retrovirus mediated gene transfer to demonstrate that marked totipotent hematopoietic stem cells are both maintained and can be amplified in such cultures, and then subsequently regenerate and sustain lympho-myeloid hematopoiesis in irradiated recipients. Marrow cells from 5-fluorouracil-treated male mice were infected with a recombinant virus carrying the neomycin resistence gene and seeded onto irradiated adherent layers of pre-established, long- term marrow cultures of female origin. At 4 weeks, cells from individual cultures were transplanted into single or multiple female recipients. Southern blot analysis of hematopoietic tissue 45 days posttransplantation showed retrovirally marked clones common to lymphoid and myeloid tissues in 14 of 23 mice examined. Strikingly, for 3 of 4 long-term cultures, multiple recipients of cells from a single flask showed marrow and thymus repopulation with the same unique retrovirally marked clone. These results establish the feasibility of retroviral-marking techniques to demonstrate the maintenance of totipotent lympho-myeloid stem cells for at least 4 weeks in the long- term marrow culture system and provide the first evidence of their proliferation in vitro. Therefore, such cultures may serve as a starting point for identifying factors that stimulate totipotent hematopoietic stem cell expansion.     

Fructus Broussonetae extract improves cognitive function and endoplasmic reticulum stress in Alzheimer's disease models

This study investigated the effects and possible targets of Fructus Broussonetiae extract,a traditional Chinese medicinal herb,on a model of Alzheimer’s disease induced by beta-amyloid peptide 25-35 and D-galactose.The results revealed that intragastric administration of Fructus Broussonetiae significantly increased the expression of immunoglobulin-binding protein,a key factor in the endoplasmic reticulum stress-signaling pathway in rat hippocampus.In contrast,the treatment significantly decreased expression levels of PKR-like endoplasmic reticulum kinase and C/EBP homologous protein,and substantially improved learning,memory and spatial recognition dysfunction in rats.This evidence indicates that Fructus Broussonetiae extract improves spatial learning and memory abilities in rats by affecting the regulation of hippocampal endoplasmic reticulum stress and activation of the apoptosis pathway.     

Ablation of PGC1 beta prevents mTOR dependent endoplasmic reticulum stress response

Mitochondria dysfunction contributes to the pathophysiology of obesity, diabetes, neurodegeneration and ageing. The peroxisome proliferator-activated receptor-gamma coactivator-1β (PGC-1β) coordinates mitochondrial biogenesis and function as well as fatty acid metabolism. It has been suggested that endoplasmic reticulum (ER) stress may be one of the mechanisms linking mitochondrial dysfunction and these pathologies. Here we investigate whether PGC-1β ablation affects the ER stress response induced by specific nutritional and pharmacological challenges in the CNS. By using flow cytometry, western blot, real time PCR and several pharmacological and nutritional interventions in PGC-1β knock out and WT mice, we confirmed that PGC-1β coordinates mitochondria function in brain and reported for the first time that a) ablation of PGC-1β is associated with constitutive activation of mTORC1 pathway associated with increased basal GRP78 protein levels in hypothalamus and cortex of animals fed chow diet; and b) in animals fed chronically with high fat diet (HFD) or high protein diet (HPD), we observed a failure to appropriately induce ER stress response in the absence of PGC-1β, associated with an increase in mTOR pathway phosphorylation. This contrasted with the appropriate upregulation of ER stress response observed in wild type littermates. Additionally, inefficient in vitro induction of ER stress by thapsigargin seems result in apoptotic neuronal cell death in PGC-1β KO. Our data indicate that PGC-1β is required for a neuronal ER response to nutritional stress imposed by HFD and HPD diets and that genetic ablation of PGC-1β might increase the susceptibility to neuronal damage and cell death.     

Dental Implants in Patients with Oral Lichen Planus: A Cross‐Sectional Study

Purpose: The main aim of this study was to evaluate the patients with oral lichen planus (OLP) and dental implants. Material and Methods: Three groups of 16 patients took part in the study. Group I patients had received dental implants and been diagnosed with OLP; Group II had not received implants but were diagnosed with OLP; Group III had implants but not OLP. Clinical observations and OLP symptoms were registered in each case. Periodontal pocket depth, implant mobility, bleeding upon probing, erythema, pain, and radiolucency around implants were measured. Patient quality of life was evaluated using OHIP 14. Results: Peri‐implant mucositis and peri‐implantitis were detected in 17.86% and 25% of the OLP‐implant group, while the control group with implants showed 18% and 16%. The implant survival rate in patients treated for OLP did not appear to differ from the survival rate among the general population. Quality of life was better among patients with implants and without OLP (p = .001). Conclusions: The results of the present study suggest that implants do not influence manifestations of OLP. OLP is not a risk factor for peri‐implantitis.     

Digital radiography of subtle pulmonary abnormalities: an ROC study of the effect of pixel size on observer performance

Forty conventional radiographs with examples of mild interstitial infiltrates and subtle pneumothoraces and 40 normal studies of the chest were selected and digitized, with pixel sizes of 1.0, 0.5, 0.2, and 0.1 mm. Observer performance tests were carried out using receiver operating characteristic analysis. Conventional radiographs and digitized images were compared. The results indicate that, in such cases, diagnostic accuracy increases significantly as the pixel size is reduced, at least to the 0.1-mm level. We conclude that, for digital systems using screen-film or similar image receptors, use of a pixel size substantially larger than 0.1 mm may result in some loss of diagnostic accuracy.