The Role of Implant Surface Geometry on Mineralization In Vivo and In Vitro; A Transmission and Scanning Electron Microscopic Study

The purpose of th.is study was to examine the effect of substratum surface topography on bone formation in vivo and in vitro. Precise control over substratum topography was achieved using micromachining, a technique developed from the fabrication of microelectronic components. In the in vivo studies, titanium-coated epoxy replicas of micromachined surfaces were implanted subcutaneously in the parietal area of rats. After 6 weeks, bone-like tissue was found adjacent to some micromachined surfaces. Detailed observation of this tissue with the transmission electron microscope revealed osteoblast/osteocyte-like cells and a fully or partially mineralized collagenous matrix. Mineralized matrix and collagen bundles were found contacting the titanium coating without any intervening material. Mineralized tissue was not found adjacent to smooth surfaces. In vitro, enzymatically released osteogenic cells from calvarial bone produced large ( ~ 10 μm) and small ( ~ 0.5-3 μm) mineralized globules on the micromachined surfaces, whereas only small mineralized globules formed on the smooth control surfaces after 4 weeks of culture. The mineralized nature of the globules was confirmed by energy dispersive X-ray analysis. In a second osteogenic culture system, micromachined or smooth control surfaces were placed on calvarial explants. After 4 weeks, partially mineralized globules ( ~ 5 μm) were noted interspersed between cells and extracellular matrix on the micromachined surfaces but not on the smooth surfaces. This study suggests that the surface topography of an implant influences bone formation in vivo and in vitro and that micromachined surfaces of the dimensions used in these experiments promote mineralized tissue formation

Restoration of mitochondrial integrity, telomere length, and sensitivity to oxidation by in vitro culture of Fuchs’ endothelial corneal dystrophy cells

PURPOSE. Fuchs’ endothelial corneal dystrophy (FECD), a degenerative disease of the corneal endothelium that leads to vision loss, is a leading cause of corneal transplantation. The cause of this disease is still unknown, but the implication of oxidative stress is strongly suggested. In this study, we analyzed the impact of FECD on mitochondrial DNA (mtDNA) integrity and telomere length, both of which are affected by the oxidative status of the cell. METHODS. We compared the levels of total mtDNA, mtDNA common deletion (4977 bp), and relative telomere length in the corneal endothelial cells of fresh Descemet’s membraneendothelium explants and cultured cells from healthy and late stage FECD subjects. Oxidantantioxidant gene expression and sensitivity to ultraviolet A (UVA)- and H2O2-induced cell death were assessed in cultured cells. RESULTS. Our results revealed increased mtDNA levels and telomere shortening in FECD explants. We also found that cell culture restores a normal phenotype in terms of mtDNA levels, telomere length, oxidant-antioxidant gene expression balance, and sensitivity to oxidative stress-induced cell death in the FECD cells compared with the healthy cells. CONCLUSIONS. Taken together, these results bring new evidence of the implication of oxidative stress in FECD. They also show that FECD does not evenly affect the integrity of corneal endothelial cells and that cell culture can rehabilitate the molecular phenotypes related to oxidative stress by selecting the more functional FECD cells

Massively parallel determination and modeling of endonuclease substrate specificity

We describe the identification and characterization of novel homing endonucleases using genome database mining to identify putative target sites, followed by high throughput activity screening in a bacterial selection system. We characterized the substrate specificity and kinetics of these endonucleases by monitoring DNA cleavage events with deep sequencing. The endonuclease specificities revealed by these experiments can be partially recapitulated using 3D structure-based computational models. Analysis of these models together with genome sequence data provide insights into how alternative endonuclease specificities were generated during natural evolution

Pre-Travel Health Care of Immigrants Returning Home to Visit Friends and Relatives

Immigrants returning home to visit friends and relatives (VFR travelers) are at higher risk of travel-associated illness than other international travelers. We evaluated 3,707 VFR and 17,507 non-VFR travelers seen for pre-travel consultation in Global TravEpiNet during 2009–2011; all were traveling to resource-poor destinations. VFR travelers more commonly visited urban destinations than non-VFR travelers (42% versus 30%, P < 0.0001); 54% of VFR travelers were female, and 18% of VFR travelers were under 6 years old. VFR travelers sought health advice closer to their departure than non-VFR travelers (median days before departure was 17 versus 26, P < 0.0001). In multivariable analysis, being a VFR traveler was an independent predictor of declining a recommended vaccine. Missed opportunities for vaccination could be addressed by improving the timing of pre-travel health care and increasing the acceptance of vaccines. Making pre-travel health care available in primary care settings may be one step to this goal

Biocompatibility and functionality of a tissue-engineered living corneal stroma transplanted in the feline eye

PURPOSE. Corneal tissue shortage has become a major concern worldwide, which has motivated the search for alternative solutions to eye bank human eyes for corneal transplantation. Minimally invasive lamellar transplantation and tissue engineering may offer new opportunities for the rehabilitation of diseased corneas. The aim of this study was to evaluate the biocompatibility and functionality of stromal lamellar grafts tissue-engineered (TE) in vitro and transplanted in vivo in the cornea of a feline model. METHODS. The corneal stromas were engineered in culture from corneal stromal cells using the self-assembly approach, without the addition of exogenous material or scaffold. Eight healthy animals underwent two intrastromal grafts in one eye and the contralateral eye was used as a control. Animals were followed with slit-lamp ophthalmic examination, corneal esthesiometry and optical coherent tomography. Confocal microscopy, immunofluorescence, histology, and transmission electron microscopy (TEM) were performed at 4 months. RESULTS. Four months after transplantation, the TE-stromal grafts were transparent, functional, and well tolerated by the eye. All grafts remained avascular, with no signs of immune rejection, despite a short course of low-dose topical steroids. Corneal sensitivity returned to preoperative level and reinnervation of the grafts was confirmed by confocal microscopy and immunofluorescence. Histology and TEM of the TE-grafts showed a lamellar stromal structure with regular collagen fibril arrangement. CONCLUSIONS. These results open the way to an entirely new therapeutic modality. Intracorneal filling using a biocompatible, transparent, and malleable TE-stroma could be the basis for multiple types of novel therapeutic options in corneal interventional surgery

Somewhere in Europe (1947): locating Hungary within a shifting geopolitical landscape

Somewhere in Europe/Valahol Európában (Radványi, 1947) was one of the first films made in Hungary after 1945. Financed by the Hungarian Communist Party (MKP), it loudly proclaimed a broad European pertinence in an effort to privilege the universal narrative of childhoods disrupted by the war over narrowly national political concerns. The film’s story of a gang of half-starved children battling for survival in a bombed-out Central European landscape places it squarely within a transnational post-war film-making tradition. Similarities with both Italian neorealism and Soviet socialist realist cinema indicate a shared European experience of the war, but is also attributable to the international training and experience of the film’s personnel. The director Radványi had worked in the Italian industry, while the scriptwriter was the well-known film theorist Béla Balázs, who had worked in Weimar Germany and Soviet Russia. This article argues that in spite of its ostensible commitment to a communist and humanist ideology, the film gives an insight into the Hungarian national obsession with territorial integrity. Hungary’s participation in World War II on the side of the Axis, and its position as a defeated nation under Allied occupation, are seen to complicate the film text. This article contends that in spite its transnational flavour, the film’s focus on lost children wandering a borderless Europe suggests a preoccupation with the country’s uncertain position within a shifting geopolitical landscape. In turn, the film’s official reading by Nemeskürty shows an eagerness to accept the film’s representation of Hungary as a blameless victim of the war, and gives evidence of a need to insert a (false) break between the country’s wartime past as a member of the Axis, and the country’s 1968 present as a member of the Communist world order

Optimization of culture conditions for porcine corneal endothelial cells

Purpose : To optimize the growth condition of porcine corneal endothelial cells (PCEC), we evaluated the effect of coculturing with a feeder layer (irradiated 3T3 fibroblasts) with the addition of various exogenous factors, such as epidermal growth factor (EGF), nerve growth factor (NGF), bovine pituitary extract (BPE), ascorbic acid, and chondroitin sulfate, on cell proliferation, size, and morphology. Methods : PCEC cultures were seeded at an initial cell density of 400 cells/cm2 in the presence or absence of 20,000 murine-irradiated 3T3 fibroblast/cm2 in the classic media Dulbecco's Modified Eagle's Medium (DMEM) supplemented with 20% fetal bovine serum (FBS). Mean cell size and bromodeoxyuridine incorporation was assessed at various passages. Growth-promoting factors were studies by seeding PCEC at 8,000 cells/cm2 in DMEM with 20% FBS or Opti-MEM I supplemented with 4% FBS and one of the following additives: EGF (0.5, 5, 25 ng/ml), NGF (5, 20, 50 ng/ml), BPE (25, 50, 100, 200 μg/ml), ascorbic acid (10, 20, 40 μg/ml) and chondroitin sulfate (0.03, 0.08, 1.6%), alone or in combination. Cell number, size and morphology of PCEC were assessed on different cell populations. Each experiment was repeated at least twice in three sets. In some cases, cell cultures were maintained after confluence to observe post-confluence changes in cell morphology. Results : Co-cultures of PCEC grown in DMEM 20% FBS with a 3T3 feeder layer improved the preservation of small polygonal cell shape. EGF, NGF, and chondroitin sulfate did not induce proliferation above basal level nor did these additives help maintain a small size. However, chondroitin sulfate did help preserve a good morphology. BPE and ascorbic acid had dose-dependent effects on proliferation. The combination of BPE, chondroitin sulfate, and ascorbic acid significantly increased cell numbers above those achieved with serum alone. No noticeable changes were observed when PCEC were cocultured with a 3T3 feeder layer in the final selected medium. Conclusions : Improvements have been made for the culture of PCEC. The final selected medium consistently allowed the growth of a contact-inhibited cell monolayer of small, polygonal-shaped cells

An epidemiological study of physical activity patterns and weight gain in physically active and sedentary pregnant women in Tshwane, South Africa

Physical activity during pregnancy has been investigated for its potential benefits which includes weight control. Physical activity patterns of pregnant women in Tshwane, South Africa, were investigated using the EPIC–Norfolk Physical Activity Questionnaire (EPAQ-2) in an epidemiological cross-sectional study. Differences between recalled pre-pregnancy weight and pregnancy weight were used to determine weight gain. Weight gain was calculated to determine its association with the physical activity levels of pregnant women in their second and third trimesters and to assess how the progression of the pregnancy affects this variable. Of the 78 women who participated, 31 (39.7%) and 47 (60.3%) were in their second and third trimesters, respectively; 30.8%, 53.9% and 16.7% were classified as relatively inactive, active and very active respectively. The weight gain of 45.5% of the pregnant women was within the recommended range, while 28.6% and 26.0% were below and above the range respectively. Non-parametric statistics indicated no connection between the trimester and the women’s activity level. Very active and relatively inactive pregnant women fall below and above the recommended weight-gain ranges, respectively (p>0.10). Of the pregnant women, 35 (53.9%) were relatively active and 35 (45.5%) fall within the recommended weight-gain ranges. In conclusion, no connection was established between the pregnancy trimester and the level of physical activity, while physical activity effectively controlled weight gain during pregnancy. This study was limited by its cross-sectional nature, therefore further longitudinal research is recommended.http://www.ajol.info/journal_index.php?jid=153&ab=ajpher