Natural estrogens enhance the engraftment of human hematopoietic stem and progenitor cells in immunodeficient mice

Hematopoietic stem and progenitor cells (HSPC) are crucial in the maintenance of lifelong production of all blood cells. These stem cells are highly regulated to maintain homeostasis through a delicate balance between quiescence, self-renewal and differentiation. However, this balance is altered during the recovery after HSPC transplantation. Transplantation efficacy can be limited by inadequate hematopoietic stem cell number, poor homing, low level of engraftment, or limited self-renewal. As recent evidence indicates that estrogens are involved in regulating hematopoiesis, we sought to examine whether natural estrogens (estrone or E1, estradiol or E2, estriol or E3 and estetrol or E4) modulate human HSPC. Our results show that human HSPC subsets express estrogen receptors, and that signaling is activated by E2 and E4 on these cells. Additionally, these natural estrogens cause different effects on human progenitors in vitro. We found that both E2 and E4 expand human HSPC. However, E4 was the best tolerated estrogen and promoted cell cycling of human hematopoietic progenitors. Furthermore, we found that E2 and, more significantly, E4 doubled human hematopoietic engraftment in immunodeficient mice without altering other HSPC properties. Finally, the impact of E4 on promoting human hematopoietic engraftment in immunodeficient mice might be mediated through the regulation of mesenchymal stromal cells in the bone marrow niche. Collectively, our data demonstrate that E4 is well tolerated and enhances human reconstitution in immunodeficient mice directly, by modulating human hematopoietic progenitor properties, and indirectly, by interacting with the bone marrow niche. This might have particular relevance for improving hematopoietic recovery after myeloablative conditioning, especially when limited numbers of HSPC are available.     

Liver fibrosis induced by hepatic overexpression of PDGF-B in transgenic mice

BACKGROUND/AIMS: In hepatic fibrogenesis, stellate cells are activated leading to production and deposition of extracellular matrix. To clarify the role of PDGF-B in liver fibrogenesis, we overexpressed PDGF-B in the liver of transgenic mice. METHODS: Transgenic mice for the conditional overexpression of PDGF-B in the liver under control of an albumin promoter were generated utilising the Cre/loxP system. Constitutive PDGF-B expression was achieved after breeding with mice expressing Cre-recombinase under actin promoter control. Tamoxifen inducible expression was achieved after breeding with mice expressing Cre under transthyretin receptor promoter control. Levels of fibrosis were assessed and the expression of regulators of matrix remodelling was measured. RESULTS: PDGF-B expression caused hepatic stellate cell and myofibroblast activation marked by alpha-smooth muscle actin and PDGFR-beta expression. Liver fibrosis was verified macroscopically, histologically and by collagen I mRNA quantification in 4-6 week-old animals. MMP-2, MMP-9 and TIMP-1 were upregulated whereas TGF-beta expression was unchanged. CONCLUSIONS: We identified PDGF-B as a proliferative and profibrogenic stimulus and potential inducer of stellate cell transdifferentiation in vivo. PDGF-B overexpression causes liver fibrosis without significantly upregulating TGF-beta1, suggesting a TGF-beta-independent mechanism. The established model provides a tool for testing anti-PDGF-B therapeutic strategies in liver fibrosis in vivo.     

Colorectal cancer prognosis twenty years later

AIM:To evaluate changes in colorectal cancer(CRC) survival over the last 20 years.METHODS:We compared two groups of consecutive CRC patients that were prospectively recruited:Group Ⅰincluded 1990 patients diagnosed between 1980 and 1994.GroupⅡincluded 871 patients diagnosed in 2001.RESULTS:The average follow up time was 21 mo(1-229)for GroupⅠand 50 mo(1-73.4)for GroupⅡ.Overall median survival was significantly longer in Group Ⅱthan in GroupⅠ(73 mo vs 25 mo,P<0.001)and the difference was significant for all ...     

Mobile ECMO in COVID-19 patient: case report

Journal of Artificial Organs - At July 25, 2020, WHO had recorded more than 16.1 million confirmed COVID-19 cases, 1% of them developed critical illness. These patients can experience rapid...     

Increased prooxidant production and enhanced susceptibility to glutathione depletion in HepG2 cells co-expressing HCV core protein and CYP2E1

Hepatitis C virus (HCV) and HCV core protein are hypothesized to induce hepatic oxidative stress and exacerbate injury caused by other toxins such as ethanol that induce the cytochrome P450 enzyme, CYP2E1. In the current study, the effects of HCV core protein [sequence genotype 1b, (nt 342-915)] on parameters indicative of oxidative stress were evaluated in HepG2 cells stably over expressing CYP2E1 (E47), or vector controls (C34). Stable (>10 passages) expression of HCV core protein and CYP2E1 was confirmed in clonal cell lines at the level of mRNA and immunoreactive protein. Prooxidant production, as determined by cellular oxidation of dichlorodihydrofluorescin and dihydroethidium (HE), was increased by expression of HCV core protein in the presence or absence of CYP2E1. Depletion of glutathione (GSH) with buthionine sulfoximine (BSO) enhanced prooxidant production in both C34 and E47 cells. In addition, prooxidant production was greater in BSO-treated cells expressing HCV core protein, and this effect was further enhanced in cells expressing both HCV core and CYP2E1. The CYP2E1 inhibitor, 4-methylpyrazole, could suppress increased prooxidant production in E47 cells. Finally, cells co-expressing both CYP2E1 and HCV core protein showed significantly decreased viability following GSH depletion. These studies show simultaneous expression of HCV core protein and CYP2E1 increases parameters indicative of oxidative stress as well as sensitization to cell injury induced by GSH depletion. These results support the hypothesis that enhanced injury in hepatocytes over expressing both HCV core protein and CYP2E1 is mediated by increases in oxidative stress.     

A customized metal guide for controllable modification of anterior teeth contour prior to minimally invasive preparation

ObjectiveOptimal tooth reduction is a key requirement for aesthetics, function, and the longevity of fixed restorations. Research has demonstrated that controlled and conservative tooth preparation is crucial for the long-term success of adhesive restorations. Different techniques of fabricating reduction guides have been previously reported in literature. The present technical note describes the fabrication technique and clinical application of a customized metal preparation reduction guide.Material and methodPatient presented with tilted maxillary left central incisor. The flared-out part of the tooth was modified prior to veneer restoration preparation. Resin pattern reduction guide was fabricated on the diagnostic cast with a window on the tilted mesial portion of the tooth. After intraoral evaluation, resin pattern guide was casted. Metal reduction guide was place intraorally and reduction was provided on the exposed surface of the tooth. After the removal of the tilted portion, a harmonious arch form allowed the clinician to provide adequate evaluation and preparation for veneer restorations.ResultsThe device demonstrated good practical value, allowing for selective and controlled reduction of tooth structure, and definitive protection of adjacent tooth surfaces from iatrogenic damage. The clinical outcome successfully addressed the patient’s restorative and aesthetic needs, and the veneer was stable 2 years postoperatively.ConclusionUse of a metal guide assists clinicians to provide a more predictable reduction of a desired tooth surface, while decreasing the risk of compromising the other/adjacent tooth surfaces.     

Comparative effect of an essential oil mouthrinse on plaque,gingivitis and salivary Streptococcus mutans levels: a double blind randomized study

An open, randomized, controlled study with two parallel treatment groups was done to evaluate the efficacy of a Lippia sidoides essential oil (EO) 1% mouthrinse compared with chlorhexidine 0.12% mouthrinse, applied two times daily for 1 week, in the treatment of dental plaque and gingivitis. Fifty‐five patients were included in the study. The efficacy variables were the colony count of Streptococcus mutans from the stimulated saliva and periodontal indices on days 0, 7 and 30 after commencement of therapy. Twenty eight patients received chlorhexidine mouthrinse (Periogard^®) and 27 Lippia sidoides essential oil mouthrinse (Cepakill^®). The clinical and microbiological parameters were significantly reduced by both mouthrinses. No significant difference was seen between the two groups (p > 0.05). There was a significant reduction in the colony count of S. mutans in both groups (p < 0.05). Chlorhexidine treatment reduced more efficiently than L. sidoides, however, no statistical difference was seen, the efficacy of both groups was similar (p = 0.3). The results indicate that Chlorhexidine mouthrinse reduced plaque index, gingival bleeding and the number of CFU (colonies forming units) more efficiently than L. sidoides but did not reach statistical significance. This study demonstrated that Lippia sidoides EO mouthrinse is effective in reducing microbial plaque and gingival inflammation. Copyright © 2009 John Wiley & Sons, Ltd.