E2A regulates neural ectoderm fate specification in human embryonic stem cells.

E protein transcription factors are crucial for many cell fate decisions. However, the roles of E proteins in the germ-layer specification of human embryonic stem cells (hESCs) are poorly understood. We disrupted the TCF3 gene locus to delete the E protein E2A in hESCs. E2A knockout (KO) hESCs retained key features of pluripotency, but displayed decreased neural ectoderm coupled with enhanced mesoendoderm outcomes. Genome-wide analyses showed that E2A directly regulates neural ectoderm and Nodal pathway genes. Accordingly, inhibition of Nodal or E2A overexpression partially rescued the neural ectoderm defect in E2A KO hESCs. Loss of E2A had little impact on the epigenetic landscape of hESCs, whereas E2A KO neural precursors displayed increased accessibility of the gene locus encoding the Nodal agonist CRIPTO. Double-deletion of both E2A and HEB (TCF12) resulted in a more severe neural ectoderm defect. Therefore, this study reveals critical context-dependent functions for E2A in human neural ectoderm fate specification.

Diffusion-weighted imaging in the assessment of cervical cancer: comparison of reduced field-of-view diffusion-weighted imaging and conventional techniques.

BACKGROUND: Cervical cancer (CC) is the second most common cancer in women worldwide. Diffusion-weighted imaging (DWI) plays an important role in the diagnosis of CC, but the conventional techniques are affected by many factors. PURPOSE: To compare reduced-field-of-view (r-FOV) and full-field-of-view (f-FOV) DWI in the diagnosis of CC. MATERIAL AND METHODS: Preoperative magnetic resonance imaging (MRI) with r-FOV and f-FOV DWI images were collected. Two radiologists reviewed the images using a subjective 4-point scale for anatomical features, magnetic susceptibility artifacts, visual distortion, and overall diagnostic confidence for r-FOV and f-FOV DWI. The objective features included the region of interest (ROI) signal intensity of the cervical lesion (SIlesion) and gluteus maximus muscle (SIgluteus), standard deviation of the background noise (SDbackground), signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR). The differences of measured apparent diffusion coefficient (ADC) values between the two examinations in pathological grades and FIGO tumor stages were compared. RESULTS: A total of 200 patients were included (170 with squamous cell carcinoma and 30 with adenocarcinoma). The scores of anatomical features, magnetic susceptibility artifacts, visual distortion, and overall diagnostic confidence for r-FOV DWI were significantly higher than those for f-FOV DWI. There was no difference in SNR and CNR between r-FOV DWI and f-FOV DWI. There were significant differences in ADC values between the two groups in all comparisons (P < 0.05). CONCLUSION: Compared with f-FOV DWI, r-FOV DWI might provide clearer imaging, fewer artifacts, less distortion, and higher image quality for the diagnosis of CC and might assist in the detection of CC.

Infection with Trypanosoma lewisi or Trypanosoma musculi may promote the spread of Toxoplasma gondii.

Toxoplasma gondii can infect almost all warm-blooded vertebrates with pathogensis being largely influenced by the host immune status. As important epidemiological hosts, rodents are globally distributed and are also commonly found infected with haemoflagellates, such as those in the genus Trypanosoma. We here address whether and how co-infection with trypanosomes can influence T. gondii infection in laboratory models. Rats of five strains, co-infected with T. lewisi and mice of four strains, co-infected with T. musculi, were found to be more or less susceptible to T. gondii infection, respectively, with corresponding increased or decreased brain cyst burdens. Downregulation of iNOS expression and decreased NO production or reverse were observed in the peritoneal macrophages of rats or mice, infected with trypanosomes, respectively. Trypanosoma lewisi and T. musculi can modulate host immune responses, either by enhancement or suppression and influence the outcome of Toxoplasma infection.

MFN2 silencing promotes neural differentiation of embryonic stem cells via the Akt signaling pathway.

Mitofusin 2 (MFN2) is a regulatory protein participating in mitochondria dynamics, cell proliferation, death, differentiation, and so on. This study aims at revealing the functional role of MFN2 in the pluripotency maintenance and primitive differetiation of embryonic stem cell (ESCs). A dox inducible silencing and routine overexpressing approach was used to downregulate and upregulate MFN2 expression, respectively. We have compared the morphology, cell proliferation, and expression level of pluripotent genes in various groups. We also used directed differentiation methods to test the differentiation capacity of various groups. The Akt signaling pathway was explored by the western blot assay. MFN2 upregulation in ESCs exhibited a typical cell morphology and similar cell proliferation, but decreased pluripotent gene markers. In addition, MFN2 overexpression inhibited ESCs differentiation into the mesendoderm, while MFN2 silencing ESCs exhibited a normal cell morphology, slower cell proliferation and elevated pluripotency markers. For differentiation, MFN2 silencing ESCs exhibited enhanced three germs' differentiation ability. Moreover, the protein levels of phosphorylated Akt308 and Akt473 decreased in MFN2 silenced ESCs, and recovered in the neural differentiation process. When treated with the Akt inhibitor, the neural differentiation capacity of the MFN2 silenced ESCs can reverse to a normal level. Taken together, the data indicated that the appropriate level of MFN2 expression is essential for pluripotency and differentiation capacity in ESCs. The increased neural differentiation ability by MFN2 silencing is strongly related to the Akt signaling pathway.

Tcf12, A Member of Basic Helix-Loop-Helix Transcription Factors, Mediates Bone Marrow Mesenchymal Stem Cell Osteogenic Differentiation In Vitro and In Vivo.

Several basic Helix-Loop-Helix transcription factors have recently been identified to regulate mesenchymal stem cell (MSC) differentiation. In the present study, Tcf12 was investigated for its involvement in the osteoblastic cell commitment of MSCs. Tcf12 was found highly expressed in undifferentiated MSCs whereas its expression decreased following osteogenic culture differentiation. Interestingly, Tcf12 endogenous silencing using shRNA lentivirus significantly promoted the differentiation ability of MSCs evaluated by alkaline phosphatase staining, alizarin red staining and expression of osteoblast-specific markers by real-time PCR. Conversely, overexpression of Tcf12 in MSCs suppressed osteoblast differentiation. It was further found that silencing of Tcf12 activated bone morphogenetic protein (BMP) signaling and extracellular signal-regulated kinase (Erk)1/2 signaling pathway activity and upregulated the expression of phospho-SMAD1 and phospho-Erk1/2. A BMP inhibitor (LDN-193189) and Erk1/2 signaling pathway inhibitor (U0126) reduced these findings in the Tcf12 silencing group. Following these in vitro results, a poly-L-lactic acid/Hydroxyappatite scaffold carrying Tcf12 silencing lentivirus was utilized to investigate the repair of bone defects in vivo. The use of Tcf12 silencing lentivirus significantly promoted new bone formation in 3-mm mouse calvarial defects as assessed by micro-CT and histological examination whereas overexpression of Tcf12 inhibited new bone formation. Collectively, these data indicate that Tcf12 is a transcription factor highly expressed in the nuclei of stem cells and its downregulation plays an essential role in osteoblast differentiation partially via BMP and Erk1/2 signaling pathways. Stem Cells 2017;35:386-397.

Investigation of infectivity of neonates and adults from different rat strains to Toxoplasma gondii Prugniaud shows both variation which correlates with iNOS and Arginase-1 activity and increased susceptibility of neonates to infection.

Mouse models differ considerably from humans with regard to clinical symptoms of toxoplasmosis caused by Toxoplasma gondii and, by comparison, the rat model is more representative of this disease in humans. In the present study, we found that different strains of adult and newborn rats (Lewis, Wistar, Sprague Dawley, Brown Norway and Fischer 344) exhibited remarkable variation in the number of brain cysts following inoculation with the T.gondii Prugniaud strain. In adult rats, large numbers of cysts (1231 ± 165.6) were observed in Fischer 344, but none in the other four. This situation was different in newborn rats aged from 5 to 20 days old. All Fischer 344 and Brown Norway newborns were cyst-positive while cyst-positive infection in Sprague Dawley neonates ranged from 54.5% to 60% depending on their age at infection. In Wistar and Lewis rat neonates, however, cyst-positivity rates of 0-42.9% and 0-25% were found respectively. To investigate whether rat strain differences in infectivity could be related to inherent strain and genetic differences in the host immune response, we correlated our data with previously reported strain differences in iNOS/Arginase ratio in adult rats and found them to be linked. These results show that interactions between host genetic background and age of rat influence T.gondii infection.

Toxoplasma gondii infection in the peritoneal macrophages of rats treated with glucocorticoids.

It is well known that toxoplasmosis can be life threatening to immunocompromised individuals such as AIDS and organ transplantation patients. Glucocorticoids (GCs) are widely used in the clinic for the treatment of autoimmune diseases and organ transplantation resulting in acute toxoplasmosis in these patients. However, the interaction and mechanism between the development of acute toxoplasmosis and GC therapy are still unknown. The aims of this study were to investigate the infection of Toxoplasma gondii in the peritoneal macrophages of rats treated with glucocorticoids. Our results showed that the growth rate of T. gondii RH strain was significantly increased in the peritoneal macrophages of rats treated with glucocorticoids in vivo. For instance, 242 (±16) tachyzoites were found in 100 macrophages from the rats treated with methylprednisolone (MP), while only 16 (±4) tachyzoites were counted in the macrophages from the non-treated control rats 24 h after infection (P < 0.01). We also demonstrated that a significant inhibition of nitric oxide (NO) production was detected in the macrophages collected from the rats post-treated with GCs with 12.90 µM (±0.99 µM) of nitrite production from the rats treated with MP, while 30.85 µM (±1.62 µM) was found in the non-treated control rats 36 h after incubation (P < 0.01). Furthermore, glucocorticoids could significantly inhibit the expression of inducible nitric oxide synthase mRNA and its protein in the rat peritoneal macrophages. Our results strongly indicate that the decrease of NO in the rat peritoneal macrophages is closely linked to the cause of acute toxoplasmosis in the host. Additionally, there was a significant increase in the number of cysts produced by the naturally cyst forming, T. gondii Prugniaud strain with an average of 2,795 (±422) cysts of the parasite being detected in the brains of the rats treated with dexamethasone, while only 1,356 (±490) cysts were found in the non-treated control animals (P < 0.01). As rats and humans are both naturally resistant to T. gondii infection, these novel data could lead to a better understanding of the development of acute toxoplasmosis during glucocorticoid therapy in humans.

Exploring the Role of First-Person Singular Pronouns in Detecting Suicidal Ideation: A Machine Learning Analysis of Clinical Transcripts.

Linguistic features, particularly the use of first-person singular pronouns (FPSPs), have been identified as potential indicators of suicidal ideation. Machine learning (ML) and natural language processing (NLP) have shown potential in suicide detection, but their clinical applicability remains underexplored. This study aimed to identify linguistic features associated with suicidal ideation and develop ML models for detection. NLP techniques were applied to clinical interview transcripts (n = 319) to extract relevant features, including four cases of FPSP (subjective, objective, dative, and possessive cases) and first-person plural pronouns (FPPPs). Logistic regression analyses were conducted for each linguistic feature, controlling for age, gender, and depression. Gradient boosting, support vector machine, random forest, decision tree, and logistic regression were trained and evaluated. Results indicated that all four cases of FPSPs were associated with depression (p < 0.05) but only the use of objective FPSPs was significantly associated with suicidal ideation (p = 0.02). Logistic regression and support vector machine models successfully detected suicidal ideation, achieving an area under the curve (AUC) of 0.57 (p < 0.05). In conclusion, FPSPs identified during clinical interviews might be a promising indicator of suicidal ideation in Chinese patients. ML algorithms might have the potential to aid clinicians in improving the detection of suicidal ideation in clinical settings.

Systematic characterization of the HOXA9 downstream targets in MLL-r leukemia by noncoding CRISPR screens.

Accumulating evidence indicates that HOXA9 dysregulation is necessary and sufficient for leukemic transformation and maintenance. However, it remains largely unknown how HOXA9, as a homeobox transcriptional factor, binds to noncoding regulatory sequences and controls the downstream genes. Here, we conduct dropout CRISPR screens against 229 HOXA9-bound peaks identified by ChIP-seq. Integrative data analysis identifies reproducible noncoding hits, including those located in the distal enhancer of FLT3 and intron of CDK6. The Cas9-editing and dCas9-KRAB silencing of the HOXA9-bound sites significantly reduce corresponding gene transcription and impair cell proliferation in vitro, and in vivo by transplantation into NSG female mice. In addition, RNA-seq, Q-PCR analysis, chromatin accessibility change, and chromatin conformation evaluation uncover the noncoding regulation mechanism of HOXA9 and its functional downstream genes. In summary, our work improves our understanding of how HOXA9-associated transcription programs reconstruct the regulatory network specifying MLL-r dependency.

MFN2 knockdown promotes osteogenic differentiation of iPSC-MSCs through aerobic glycolysis mediated by the Wnt/ß-catenin signaling pathway.

BACKGROUND: Mitofusin-2 (MFN2) is a kind of GTPase that participates in the regulation of mitochondrial fusion, which is related to a variety of physiological and pathological processes, including energy metabolism, cell differentiation, and embryonic development. However, it remains unclear whether MFN2 is involved in the metabolism and osteogenic differentiation of mesenchymal stem cells (MSCs). METHODS: MFN2 knockdown (MFN2-KD) and MFN2-overexpressing (MFN2-OE) induced pluripotent stem cell-derived mesenchymal stem cells (iPSC-MSCs) were constructed by lentivirus. The commercial kits were utilized to detect the glycolysis and oxidative phosphorylation (OXPHOS) rate. Flow cytometry, Western blot, quantitative real-time polymerase chain reaction (qRT-PCR), RNA-seq, immunofluorescence, and immunoprecipitation were employed for phenotype and molecular mechanism assessment. RESULTS: We demonstrated that MFN2 and Wnt/ß-catenin signaling pathway regulated glycolysis of iPSC-MSCs. The lack of MFN2 promoted the osteogenic differentiation of iPSC-MSCs, and aerobic glycolysis in the presence of sufficient oxygen, which increased glucose consumption and lactic acid production, as well as the glycolytic enzyme activity and gene expression. Inhibiting the Wnt/ß-catenin signaling pathway normalized the enhanced glycolytic rate and osteogenic differentiation of MFN2-KD iPSC-MSCs. MFN2-OE iPSC-MSCs displayed the opposite phenotype. CONCLUSIONS: Downregulating MFN2 promotes osteogenic differentiation of iPSC-MSCs through aerobic glycolysis mediated by the Wnt/ß-catenin signaling pathway. Our research reveals the new function of MFN2 in regulating the osteogenic differentiation and energy metabolism of MSCs, which will provide a new therapeutic target and theoretical basis for alveolar bone repair and periodontal regenerative treatment.

Understanding the Information Needs of Patients With Ovarian Cancer Regarding Genetic Testing to Inform Intervention Design: Interview Study.

BACKGROUND: Experts in gynecological cancer care recommend that all patients with invasive or high-grade ovarian cancer (OC) undergo genetic testing. However, even patients who intend to take or have taken genetic tests have many unaddressed information needs regarding genetic testing. Existing genetic counseling falls short of adequately addressing this challenge. OBJECTIVE: This study aims to investigate the genetic testing-related information needs of patients with OC to inform the design of interactive technology-based interventions that can enhance communication of genetic testing information to patients. METHODS: We interviewed 20 patients with OC who had taken genetic tests and gathered genetic testing-related messages from an active OC web-based community. The interview transcripts and web-based community messages were analyzed using the qualitative content analysis method. RESULTS: Data analyses produced a comprehensive taxonomy of the genetic testing-related information needs of patients with OC, which included five major topic clusters: knowledge of genetic testing as a medical test, genetic testing process, genetic testing implications for patients, implications for family members, and medical terminology. Findings indicated that patients wanted to receive information that was relevant, understandable, concise, usable, appropriate, sympathetic, and available when needed. They also preferred various channels to receive information, including internet-based technologies, print, and conversations with health care providers. CONCLUSIONS: Patients with OC need a range of information to address the uncertainties and challenges that they encounter while taking genetic tests. Their preferences for channels to receive information vary widely. A multichannel information delivery solution that combines both provider-led and peer-to-peer education models is needed to supplement existing genetic counseling to effectively meet the genetic testing-related information needs of patients with OC.

Exploring the Effects of Land Use Changes on the Landscape Pattern and Soil Erosion of Western Hubei Province from 2000 to 2020.

Accelerated land use and land cover changes affect regional landscape patterns and change the ecological environment, including soil conservation capabilities. This is not conducive to the sustainable development of human society. In this research, we explored the land use change pattern and landscape change pattern in western Hubei from 2000 to 2020. Using the Chinese soil loss equation and stepwise regression, we measure how landscape patterns affect soil erosion under land use and cover changes in western Hubei Province. The results show that average soil erosion in the mountainous areas of western Hubei tended to increase from 2000 to 2010 and decrease from 2010 to 2020; soil erosion was higher in the western than in the eastern part of the study area. The land in areas with high-intensity and low-intensity soil erosion was mainly waterfront/grassland and cropland/forestland, respectively, and the area of moderate to severe soil erosion was greatest when the slope was 10-20°. When the slope exceeded 20°, the soil erosion area of each grade tended to decrease; thus, 20° is the critical slope for soil erosion in the study area. The landscape pattern in mountainous areas changed dramatically from 2000 to 2020. At the landscape level, landscape fragmentation increased and connectivity decreased, but the area of landscape diversity was stable. Soil erosion in western Hubei was positively correlated with the contiguity index, aggregation index and largest patch index but negatively correlated with the Shannon evenness index. The higher the landscape fragmentation and the greater the accumulation of single land-use types, the more severe the soil erosion is, while the higher the landscape connectivity and the richer the landscape diversity, the less severe the soil erosion is. The results can inform regional landscape management and soil conservation research.

Downregulating MFN2 Promotes the Differentiation of Induced Pluripotent Stem Cells into Mesenchymal Stem Cells through the PI3K/Akt/GSK-3ß/Wnt Signaling Pathway.

Understanding the mechanism of the differentiation of induced pluripotent stem cells (iPSCs) into mesenchymal stem cells (MSCs) and promoting the production efficiency of iPSC-derived MSCs (iPSC-MSCs) are critical to periodontal tissue engineering. However, the gene networks that control this differentiation process from iPSCs into MSCs are poorly understood. We demonstrated that MFN2 knockdown showed a positive effect on the triploblastic and MSC differentiation from iPSCs. Activation of the PI3K/Akt signaling pathway by MFN2 knockdown activated the Wnt/ß-catenin signaling pathway by inhibiting GSK-3ß and reducing ß-catenin degradation. Inhibitor of the PI3K/Akt signaling pathway normalized the enhanced efficiency of differentiation into MSCs of MFN2-KD iPSCs and Wnt activator-treated control iPSCs. MFN2-OE iPSCs displayed an opposite phenotype. In conclusion, downregulating MFN2 promotes the differentiation of iPSCs into MSCs by activating the PI3K/Akt/GSK-3ß/Wnt signaling pathway. Our results reveal a crucial function and mechanism for MFN2 in regulating MSC differentiation from iPSCs, which will provide new ideas for periodontal tissue engineering and periodontal regenerative treatment by using iPSC-MSCs.

Reducing the Effectiveness of Ward Particulate Matter, Bacteria and Influenza Virus by Combining Two Complementary Air Purifiers.

Air purifiers should pay much attention to hospital-associated infections, but the role of a single air purifier is limited. The goal of this study was to evaluate the effectiveness of the combined application of the nonequilibrium positive and negative oxygen ion purifier (PNOI) and the high-efficiency particulate air filter (HEPA) on a complex, polluted environment. Two of the better performing purifiers were selected before the study. The efficacy of their use alone and in combination for purification of cigarette particulate matter (PM), Staphylococcus albicans, and influenza virus were then evaluated under a simulated contaminated ward. PNAI and HEPA alone are deficient. However, when they were combined, they achieved 98.44%, 99.75%, and 100% 30 min purification rates for cigarette PM, S. albus, and influenza virus, respectively. The purification of pollution of various particle sizes and positions was optimized and reduced differentials, and a subset of airborne influenza viruses is inactivated. Furthermore, they were superior to ultraviolet disinfection for microbial purification in air. This work demonstrates the strong purification capability of the combined application of these two air purifiers for complex air pollution, which provides a new idea for infection control in medical institutions.

The Link between Landscape Characteristics and Soil Losses Rates over a Range of Spatiotemporal Scales: Hubei Province, China.

Controlling soil erosion is beneficial to the conservation of soil resources and ecological restoration. Understanding the spatial distribution characteristics of soil erosion helps find the key areas for soil control projects and optimal scale for investing in a soil and water conservation project at the lowest cost. This study aims to answer the question of how the spatial distribution of soil erosion in Hubei Province changed between 2000 and 2020. Moreover, how do the effects of natural factors and human activities on soil erosion vary over the years? What are the differences in landscape pattern characteristics and the spatial cluster of soil erosion at multiple administrative scales? We simulated the spatial distribution of soil erosion in Hubei province from 2000 to 2020 by the Chinese Soil Loss Equation model at three administrative scales. We investigated the relationship between soil erosion and driving factors by Geodector. We explored the landscape pattern and hotspots of land at different levels of soil erosion by Fragstat and hotspot analysis. The results show that: (1) The average soil erosion rate decreased from 2000 to 2020. Soil erosion is severe in the mountainous areas of western Hubei province, while it is less severe in the central plains. (2) Land-cover type, precipitation, and normalized difference vegetation index are the most influencing factors of soil erosion in 2000-2010, 2015, and 2020, respectively. (3) The aggregation index values at the town scale are higher than those at the city and county scales, while the fractal dimension index values at the town scale are lower, which indicates that soil erosion projects are most efficient when the project unit is 'town'. (4) At the town scale, if the hotspot area (6.84% of the total area) is treated as the protection target, it can reduce 50.42% of the total soil erosion of Hubei province. Hotspots of soil erosion overlap with high erosion zones, mainly in the northwestern, northeastern, and southwestern parts of Hubei province in 2000, while the hotspots in northwestern Hubei disappear in 2020. In conclusion, land managers in Hubei should optimize the land-use structure, soil and water conservation in slope land, and eco-engineering controls at the town scale.

Correction: Strontium-incorporated mesoporous bioactive glass scaffolds stimulating in vitro proliferation and differentiation of bone marrow stromal cells and in vivo regeneration of osteoporotic bone defects.

Correction for 'Strontium-incorporated mesoporous bioactive glass scaffolds stimulating in vitro proliferation and differentiation of bone marrow stromal cells and in vivo regeneration of osteoporotic bone defects' by Yufeng Zhang et al., J. Mater. Chem. B, 2013, 1, 5711-5722.

Ddit3 suppresses the differentiation of mouse chondroprogenitor cells.

Endochondral ossification is an essential skeletal development process which is strongly linked to chondrocyte differentiation. DNA damage-inducible transcript 3 (Ddit3), a member of the CCAAT/enhancer-binding protein family of transcription factors, is highly expressed in the cartilage plate. However, the role of DNA damage-inducible transcript 3 in chondrocyte differentiation remains to be investigated. Immunofluorescent staining was used to detect Ddit3 expression in the mouse growth plate and in the mouse chondroprogenitor cell line ATDC5. A lentivirus system was employed to overexpress Ddit3 and silence its endogenous expression in ATDC5 cells. The differentiation abilities of ATDC5 cells were examined through quantitative reverse transcription polymerase chain reaction (qRT-PCR) and chondrogenic and hypertrophic-related staining. Western blot analysis was performed to detect the protein expression of sex-determining region Y-type high-mobility group box 9 and CCAAT/enhancer-binding protein ß. Ddit3 was expressed in the proliferative and hypertrophic zones of the mouse growth plate. Ddit3 knockdown significantly enhanced the expression of chondrogenic and hypertrophic markers, whereas Ddit3 overexpression decreased the expression of these markers. This finding was also evidenced by Alcian blue staining, proteoglycan synthesis and alkaline phosphatase assay. Additionally, Ddit3 down-regulation significantly led to Sox9 up-regulation. These results suggest that Ddit3 suppresses the differentiation of ATDC5 cells. The function of Ddit3 might partially be regulated by Sox9 expression during chondrogenic and hypertrophic differentiation.

Strontium-incorporated mesoporous bioactive glass scaffolds stimulating in vitro proliferation and differentiation of bone marrow stromal cells and in vivo regeneration of osteoporotic bone defects.

Osteoporosis is one of the most widely occurring bone disorders characterized by low bone mineral density and poor bone strength. Strontium ranelate, as a treatment option, has received significant attention in recent years due to its ability to halt the progress of osteoporosis by simultaneously improving bone formation and reducing bone resorption. Although much emphasis has been given to the treatment of osteoporosis and fracture prevention using pharmacological agents, much less attention has been placed on the repair of critical-sized bone fractures caused by osteoporosis. The aim of the present study was to prepare strontium-incorporated mesoporous bioactive glass (Sr-MBG) scaffolds in order to combine the therapeutic effects of Sr2+ ions on osteoporosis with the bioactivity of MBG to regenerate osteoporotic-related fractures. Prior to animal implantation, the effects of Sr-containing ionic products from Sr-MBG scaffolds on the proliferation and differentiation of bone marrow stromal cells (BMSCs) from osteoporotic bone were investigated in an in vitro culture system. The results showed that Sr-MBG scaffolds significantly increased the proliferation of BMSCs in a concentration dependent manner and were able to stimulate the expression of osteoblast differentiation markers including Alpl, Col1a1, Runx2 and Bglap as assessed by real-time PCR. Critical sized femur defects in ovariectomised rats were created to simulate an osteoporotic phenotype. At time points 2, 4 and 8 weeks post-implantation, the in vivo osteogenetic efficiency was systematically evaluated by µCT analysis, hematoxylin and eosin staining, and immunohistochemistry (type I collagen). The results showed that the incorporation of Sr into MBG scaffolds significantly stimulated new bone formation in osteoporotic bone defects when compared to MBG scaffolds alone. Furthermore, it was generally found that Sr release in blood was maintained at a very low level and the Sr, Si, Ca and P excretion by urine operated in an a similar manner to blank control animals. Our results suggested that Sr-MBG scaffolds could be a promising biomaterial for regenerating osteoporosis-related fractures by the release of Sr-containing ionic products.

Lower expression of inducible nitric oxide synthase and higher expression of arginase in rat alveolar macrophages are linked to their susceptibility to Toxoplasma gondii infection.

Rats are naturally resistant to Toxoplasma gondii infection, particularly the RH strain, while mice are not. Previous studies have demonstrated that inducible nitric oxide synthase (iNOS) and arginase-1 of rodent peritoneal macrophages are linked to the mechanism of resistance. As an increasing number of studies on human and animal infections are showing that pulmonary toxoplasmosis is one of the most severe clinical signs from T. gondii infection, we are interested to know whether T. gondii infection in alveolar macrophages of rats is also linked to the levels of iNOS and arginase-1 activity. Our results demonstrate that T. gondii could grow and proliferate in rat alveolar macrophages, both in vitro and in vivo, at levels higher than resistant rat peritoneal macrophages and at comparable levels to sensitive mouse peritoneal macrophages. Lower activity and expression levels of iNOS and higher activity and expression levels of arginase-1 in rat alveolar macrophages were found to be linked to the susceptibility of T. gondii infection in these cells. These novel findings could aid a better understanding of the pathogenesis of clinical pulmonary toxoplasmosis in humans and domestic animals.