Triple network hypothesis-related disrupted connections in schizophrenia: A spectral dynamic causal modeling analysis with functional magnetic resonance imaging.

OBJECTIVE: The symptom-related neurobiology characteristic of schizophrenia in the brain from a network perspective is still poorly understood, leading to a lack of potential biologically-based markers and difficulty identifying therapeutic targets. We aim to test the dysregulated cross-network interactions among the Salience Network (SN), Central Executive Network (CEN) and Default Mode Network (DMN) and how they contributed to different symptoms in schizophrenia patients. METHODS: We examined network interactions among the SN, CEN and DMN in 76 patients with schizophrenia vs. 80 well-matched controls using dynamic causal modeling (DCM). We further analyzed the relation between network dynamics and Positive and Negative Syndrome Scale (PANSS). RESULTS: We observed that the DMN, CEN and SN across healthy controls and schizophrenia patients showed several similarities within or between-network pattern in the resting state. Comparing schizophrenia to controls, SN-centered cross-network interactions were most significantly reduced. Crucially, the strength of connections from CEN subnetwork 1 to DMN subnetwork 1 was positively correlated with the Positive Score of PANSS. The connection from the DMN subnetwork 2 to CEN subnetwork 2 was negatively correlated with the Negative Score of PANSS. CONCLUSIONS: Our study provides strong evidence for the dysregulation among SN, CEN and DMN in a triple-network perspective in schizophrenia. The connection between DMN and CEN could be clinically-relevant neurobiological signature of schizophrenia symptoms. Our study indicated that the description of brain triple network hypothesis could be a novel and possible bio-marker for schizophrenia.

Simultaneous or Staged Decompressions for Patients with Tandem Spinal Stenosis.

OBJECTIVE: To compare the clinical effects of cervical decompression first, lumbar decompression first, or simultaneous decompression of both lesions in the treatment of tandem spinal stenosis (TSS). METHODS: This is a retrospective analysis. From January 2013 to December 2018, 51 TSS patients underwent our surgery and postoperative investigation. Among the 51 subjects, 27 females and 24 males, aged 49-77 years with an average age of 66.3 ± 6.8, were selected. According to the different operation sequences, all patients were divided into three groups. In simultaneous operation group, five patients underwent cervical and lumbar vertebrae surgery at the same time. In first cervical surgery group, 28 patients underwent cervical vertebra surgery first, followed by lumbar spine surgery after a period of recovery. And in first lumbar surgery group, 18 patients underwent lumbar vertebrae surgery first. The choice for neck surgery is posterior cervical single-door vertebroplasty, the surgery of lumber is plate excision and decompression needle-rod system internal fixation. The outcome measures are visual analogue scale (VAS), Japanese Orthopaedic Association cervical (JOA-C) and lumbar (JOA-L) scores, which were assessed at 3 months and 1 year after the operation by telephone interview. In addition, operative time, estimated blood loss, and hospital stay were also recorded. RESULTS: All the patients in the study had surgery performed successfully by the same group of orthopaedic surgeons. The preoperative VAS scores of simultaneous operation group, first cervical surgery group, and first lumbar surgery group were 8.00 ± 1.00, 8.36 ± 0.68, and 8.17 ± 0.71 (P > 0.05). The preoperative JOA-C scores were 7.00 ± 2.35, 6.54 ± 1.53, and 7.83 ± 1.04 (P < 0.05). And the preoperative JOA-L scores were 7.20 ± 2.17, 4.64 ± 2.36, and 5.78 ± 1.22 respectively (P < 0.05). During the final 1-year follow-up, the JOA-C improvement rates of simultaneous operation group, first cervical surgery group, and first lumbar surgery group were 85.68% ± 5.44%, 84.27% ± 5.02%, and 83.34% ± 10.25%, respectively (P > 0.05), and the JOA-L improvement rates were 80.04% ± 3.35%, 81.65% ± 3.74%, and 80.21% ± 4.76% (P > 0.05). The difference among them was not statistically significant. In addition, operation time (OP), blood loss (BL), and hospital stay (HS) in the simultaneous operation group were 245.00 ± 5.00 min, 480.00 ± 27.39 mL, and 16.60 ± 0.55 days, respectively. While those parameters in the first cervical surgery group were 342.50 ± 18.18 min, 528.21 ± 43.97 mL, and 22.75 ± 2.15 days, and in the first lumbar surgery group they were 346.11 ± 24.77 min, 519.44 ± 43.99 mL, and 22.89 ± 1.64 days. The average blood loss in simultaneous operation group was less (P > 0.05); meanwhile, the operation time and hospital stay time were significantly shorter in the simultaneous operation group than in the first cervical surgery group and first lumbar surgery group (P < 0.05). Only one case of fat liquefaction occurred in first cervical surgery group, which healed spontaneously after a regular change of dressing for 1 month. CONCLUSIONS: Under the condition of ensuring the surgical effect, the choice of staged surgery or concurrent surgery according to the patients' own symptoms of cervical and lumbar symptoms could both obtain satisfactory results, and the damage of simultaneous surgery was less than that of staged surgery.

Biopromoters for Gas Hydrate Formation: A Mini Review of Current Status.

Gas hydrates have promising application prospects in the fields of future energy sources, natural gas storage and transportation, CO2 capture and sequestration, gas separation, and cold energy. However, the application of hydrate technologies is being restricted due to the slow formation rate of gas hydrates. Kinetic promoters have been receiving increased attention, given that they can improve the hydrate formation rate with very small doses and do not affect gas storage capacity. However, most kinetic promoters are non-renewable, petrochemical-derived, non-degradable materials, inevitably leading to resource waste and environmental pollution. Biopromoters, derived from biomass, are renewable, biodegradable, environmentally friendly, non-toxic (or low toxic), and economically feasible. This mini review summarizes the current status of already discovered biopromoters, including lignosulfonate, amino acid, biosurfactant, and biological porous structures, which have the potential to replace petrochemical-derived promoters in hydrate technologies. Finally, future research directions are given for the development of biopromoters.

CD226 deletion improves post-infarction healing via modulating macrophage polarization in mice.

Macrophages are essential for wound repair after myocardial infarction (MI). CD226, a member of immunoglobulin superfamily, is expressed on inflammatory monocytes, however, the role of CD226 in infarct healing and the effect of CD226 on macrophage remain unknown. Methods: Wild type and CD226 knockout (CD226 KO) mice were subjected to permanent coronary ligation. CD226 expression, cardiac function and ventricular remodeling were evaluated. Profile of macrophages, myofibroblasts, angiogenesis and monocytes mobilization were determined. Results: CD226 expression increased in the infarcted heart, with a peak on day 7 after MI. CD226 KO attenuated infarct expansion and improved infarct healing after MI. CD226 deletion resulted in increased F4/80+ CD206+ M2 macrophages and diminished Mac-3+ iNOS+ M1 macrophages accumulation in the infarcted heart, as well as enrichment of α-smooth muscle actin positive myofibroblasts and Ki67+ CD31+ endothelial cells, leading to increased reparative collagen deposition and angiogenesis. Furthermore, CD226 deletion restrained inflammatory monocytes mobilization, as revealed by enhanced retention of Ly6Chi monocytes in the spleen associated with a decrease of Ly6Chi monocytes in the peripheral blood, whereas local proliferation of macrophage in the ischemic heart was not affected by CD226 deficiency. In vitro studies using bone marrow-derived macrophages showed that CD226 deletion potentiated M2 polarization and suppressed M1 polarization. Conclusion: CD226 expression is dramatically increased in the infarcted heart, and CD226 deletion improves post-infarction healing and cardiac function by favoring macrophage polarization towards reparative phenotype. Thus, inhibition of CD226 may represent a novel therapeutic approach to improve wound healing and cardiac function after MI.

A meta-analysis of selected near-road air pollutants based on concentration decay rates.

Traffic-related air pollution has been associated with various health risks for human populations living near roadways. Understanding the relationship between traffic density and dispersion of vehicle-released air pollutants is important for assessing human exposure to near-road air pollutants. We performed a literature survey targeting publications containing measurement data of traffic-related air pollutants near roads with distance information on their concentration distribution. Concentration decay rates over down-wind distance away from major roads were calculated for black carbon (BC), carbon monoxide (CO) and nitrogen oxides (NO2 or NOx) and meta-data analysis on these rates was performed. These analyses showed metadata-based exponential decay rates of 0.0026, 0.0019, 0.0004, and 0.0027 m-1 for BC, CO, NO2 and NOx, respectively. Using these measurement data-based decay rates, concentrations for BC, CO, NO2 and NOx over various near-road distances were predicted. These results are useful for enhancing exposure modeling and thus more reliably assessing the health risk of exposure to near road air pollution.

Diagnostic performance of diffusion-weighted magnetic resonance imaging in pulmonary malignant lesions: a meta-analysis.

BACKGROUND: Overuse or misuse of positron emission tomography/computed tomography (PET/CT) should be avoided for its ionizing-radiation. Diffusion-weighted magnetic resonance imaging (DW-MRI), characterized by no radiation, may be regarded as an alternative in differentiating pulmonary nodules. We aim to estimate the diagnostic accuracy of DW-MRI in diagnosing of pulmonary lesions. METHODS: Relevant studies were searched through PubMed and Embase with no language restriction from inception to March 8, 2019. We selected studies reporting sensitivity and specificity of DW-MRI for differentiating pulmonary nodules. A summary estimates of sensitivity, specificity and area under curve (AUC) of receiver operating characteristic (ROC) of DW-MRI were analyzed with a random effects model. RESULTS: We included data from 37 studies, which altogether included 2,311 pulmonary lesions. The pooled sensitivity and specificity were 0.86 (95% CI, 0.82-0.89) and 0.79 (95% CI, 0.72-0.85), and AUC was 0.90 (95% CI, 0.87-0.92). Subsequent subgroup analysis showed the higher sensitivity of DW-MRI in pulmonary lesion >2 cm in comparison to lesions ≤2 cm, however, higher specificity was observed in smaller lesions. CONCLUSIONS: Radiation-free DW-MRI showed a favorable balance between sensitivity and specificity in diagnosing pulmonary malignancies especially in lesion size ≤2 cm. Existing evidence indicated that DW-MRI may be considered as an independent substitute in diagnosis of lung lesions, which might help to prevent long-term side-effects from radiographic diagnosing and evaluating procedures.

Alterations in ß­catenin/E­cadherin complex formation during the mechanotransduction of Saos­2 osteoblastic cells.

Mechanical load application promotes bone formation, while reduced load leads to bone loss. However, the underlying mechanisms that regulate new bone formation are not fully understood. Wnt/ß­catenin signaling has an important role in bone formation, bone growth and remodeling. The aim of the present study was to investigate whether mechanical stimuli regulated bone formation through the Wnt/ß­catenin signaling pathway. Saos­2 osteoblastic cells were subjected to mechanical strain using a Flexcell strain loading system. The results demonstrated that 12% cyclical tensile stress significantly stimulated Saos­2 cell proliferation, increased the activity of alkaline phosphatase and promoted the formation of mineralized nodules, as determined by MTT and p­nitrophenyl phosphate assays and Alizarin Red S staining, respectively. Furthermore, western blot analysis demonstrated that, following mechanical strain, increased phosphorylation of glycogen synthase kinase­3ß and nuclear ß­catenin expression was observed in cells, compared with static control culture cells. Results of reporter gene and reverse transcription­polymerase chain reaction assays also demonstrated that mechanical strain significantly increased T­cell factor reporter gene activity and the mRNA expression of cyclooxygenase (COX)­2, cyclin D1, c­fos and c­Jun in Saos­2 cells. Co­immunoprecipitation analysis revealed that elongation mechanical strain activated Wnt/ß­catenin signaling and reduced ß­catenin and E­cadherin interaction in Saos­2 cells. In conclusion, the results of the current study indicate that mechanical strain may have an important role in the proliferation and differentiation of osteoblasts. The disassociation of the ß­catenin/E­cadherin complex in the osteoblast membrane under stretch loading and the subsequent translocation of ß­catenin into the nucleus may be an intrinsic mechanical signal transduction mechanism.

Evaluation of Traffic Density Parameters as an Indicator of Vehicle Emission-Related Near-Road Air Pollution: A Case Study with NEXUS Measurement Data on Black Carbon.

An important factor in evaluating health risk of near-road air pollution is to accurately estimate the traffic-related vehicle emission of air pollutants. Inclusion of traffic parameters such as road length/area, distance to roads, and traffic volume/intensity into models such as land use regression (LUR) models has improved exposure estimation. To better understand the relationship between vehicle emissions and near-road air pollution, we evaluated three traffic density-based indices: Major-Road Density (MRD), All-Traffic Density (ATD) and Heavy-Traffic Density (HTD) which represent the proportions of major roads, major road with annual average daily traffic (AADT), and major road with commercial annual average daily traffic (CAADT) in a buffered area, respectively. We evaluated the potential of these indices as vehicle emission-specific near-road air pollutant indicators by analyzing their correlation with black carbon (BC), a marker for mobile source air pollutants, using measurement data obtained from the Near-road Exposures and Effects of Urban Air Pollutants Study (NEXUS). The average BC concentrations during a day showed variations consistent with changes in traffic volume which were classified into high, medium, and low for the morning rush hours, the evening rush hours, and the rest of the day, respectively. The average correlation coefficients between BC concentrations and MRD, ATD, and HTD, were 0.26, 0.18, and 0.48, respectively, as compared with -0.31 and 0.25 for two commonly used traffic indicators: nearest distance to a major road and total length of the major road. HTD, which includes only heavy-duty diesel vehicles in its traffic count, gives statistically significant correlation coefficients for all near-road distances (50, 100, 150, 200, 250, and 300 m) that were analyzed. Generalized linear model (GLM) analyses show that season, traffic volume, HTD, and distance from major roads are highly related to BC measurements. Our analyses indicate that traffic density parameters may be more specific indicators of near-road BC concentrations for health risk studies. HTD is the best index for reflecting near-road BC concentrations which are influenced mainly by the emissions of heavy-duty diesel engines.

Effects of Mountain Uplift and Climatic Oscillations on Phylogeography and Species Divergence in Four Endangered Notopterygium Herbs.

Mountain uplift and climatic fluctuations are important driving forces that have affected the geographic distribution and population dynamics history of organisms. However, it is unclear how geological and climatic events might have affected the phylogeographic history and species divergence in high-alpine herbal plants. In this study, we analyzed the population demographic history and species differentiation of four endangered Notopterygium herbs on the high-altitude Qinghai-Tibetan Plateau (QTP) and adjacent areas. We combined phylogeographic analysis with species distribution modeling to detect the genetic variations in four Notopterygium species (N. incisum, N. franchetii, N. oviforme, and N. forrestii). In total, 559 individuals from 74 populations of the four species were analyzed based on three maternally inherited chloroplast fragments (matK, rbcL, and trnS-trnG) and one nuclear DNA region (internal transcribed spacer, ITS). Fifty-five chloroplast DNA (cpDNA) and 48 ITS haplotypes were identified in the four species. All of the cpDNA and ITS haplotypes were species-specific, except N. franchetii and N. oviforme shared one cpDNA haplotype, H32. Phylogenetic analysis suggested that all four species formed a monophyletic clade with high bootstrap support, where N. franchetii and N. oviforme were sisters. In addition, each Notopterygium species generated an individual clade that corresponded to their respective species in the ITS tree. Population dynamics analyses and species distribution modeling showed that the two widely distributed herbs N. incisum and N. franchetii exhibited obvious demographic expansions during the Pleistocene ice ages. Molecular dating suggested that the divergence of the four Notopterygium species occurred approximately between 3.6 and 1.2 Mya, and it was significantly associated with recent extensive uplifts of the QTP. Our results support the hypothesis that mountain uplift and Quaternary climatic oscillations profoundly shaped the population genetic divergence and demographic dynamics of Notopterygium species. The findings of this and previous studies provide important insights into the effects of QTP uplifts and climatic changes on phylogeography and species differentiation in high altitude mountainous areas. Our results may also facilitate the conservation of endangered herbaceous medicinal plants in the genus Notopterygium.

Temporal variability of pyrethroid metabolite levels in bedtime, morning, and 24-h urine samples for 50 adults in North Carolina.

Pyrethroid insecticides are widely used to control insects in both agricultural and residential settings worldwide. Few data are available on the temporal variability of pyrethroid metabolites in the urine of non-occupationally exposed adults. In this work, we describe the study design and sampling methodology for the Pilot Study to Estimate Human Exposures to Pyrethroids using an Exposure Reconstruction Approach (Ex-R study). Two major objectives were to quantify the concentrations of several pyrethroid metabolites in bedtime, first morning void (FMV), and 24-h urine samples as concentration (wet weight), specific-gravity (SG) corrected, creatinine (CR) corrected, and excretion rate values for 50 Ex-R adults over a six-week monitoring period and to determine if these correction approaches for urine dilution reduced the variability of the biomarker levels. The Ex-R study was conducted at the United States Environmental Protection Agency's Human Studies Facility in Chapel Hill, North Carolina USA and at participants' homes within a 40-mile radius of this facility. Recruitment of participants and field activities occurred between October 2009 and May 2011. Participants, ages 19-50 years old, provided daily food, activity, and pesticide-use diaries and collected their own urine samples (bedtime, FMV, and 24-h) during weeks 1, 2, and 6 of a six-week monitoring period. A total of 2503 urine samples were collected from the study participants. These samples were analyzed for the pyrethroid metabolites 3-phenoxybenzoic acid (3-PBA), cis/trans-3-(2,2-dichlorovinyl)-2,2-dimethyl-cyclopropane carboxylic acid (cis/trans-DCCA), and 2-methyl-3-phenylbenzoic acid (MPA) using high performance liquid chromatography/tandem mass spectrometry. Only 3-PBA was frequently detected (>50%) in the adult urine samples. Median urinary 3-PBA levels were 0.88 ng/mL, 0.96 ng/mL-SG, 1.04 ng/mg, and 1.04 ng/min for concentration, SG-corrected, CR-corrected, and excretion rate values, respectively, across all urine samples. The results showed that median urinary 3-PBA concentrations were consistently the lowest in FMV samples (0.77 ng/mL, 0.68 ng/mL-SG, 0.68 ng/mg, and 0.58 ng/min) and the highest in 24-h samples (0.92 ng/mL, 1.06 ng/mL-SG, 1.18 ng/mg, and 1.19 ng/min) across all four methods. Intraclass correlation coefficient (ICC) estimates for 3-PBA indicated poor reproducibility (<0.22) for all urine sample types and methods over a day, week, and six weeks. Correcting for urine sample dilution, based on either SG, CR or urine output, introduced additional measurement variability both between- and within-individuals. These results indicate that a single measure of urinary 3-PBA was not sufficient to characterize average exposure regardless of sample type, correction method, and time frame of collection. In addition, the study results can be used to inform the design of exposure characterization strategies in relevant environmental epidemiology studies in the future.

Proteomics based detection of differentially expressed proteins in human osteoblasts subjected to mechanical stress.

Mechanical stress is essential for bone development. Mechanical stimuli are transduced to biochemical signals that regulate proliferation, differentiation, and cytoskeletal reorganization in osteoblasts. In this study, we used proteomics to evaluate differences in the protein expression profiles of untreated Saos-2 osteoblast cells and Saos-2 cells subjected to mechanical stress loading. Using 2-D electrophoresis, MALDI-TOF mass spectroscopy, and bioinformatics, we identified a total of 26 proteins differentially expressed in stress loaded cells compared with control cells. Stress loaded Saos-2 cells exhibited significant upregulation of 17 proteins and significant downregulation of 9 proteins compared with control cells. Proteins that were most significantly upregulated in mechanically loaded cells included those regulating osteogenesis, energy metabolism, and the stress response, such as eukaryotic initiation factor 2 (12-fold), mitochondrial ATP synthase (8-fold), and peptidylprolyl isomerase A (cyclophilin A)-like 3 (6.5-fold). Among the proteins that were significantly downregulated were those involved in specific signaling pathways and cell proliferation, such as protein phosphatase regulatory (inhibitor) subunit 12B (13.8-fold), l-lactate dehydrogenase B (9.4-fold), Chain B proteasome activator Reg (Alpha) PA28 (7.7-fold), and ubiquitin carboxyl-terminal esterase L1 (6.9-fold). Our results provide a platform to understand the molecular mechanisms underlying mechanotransduction.

Expression of FGF4 mRNA is mediated by mating behaviours in mice.

In mammals, breeding is preceded by species-specific mating behaviours. In this study, we investigated whether parthenogenetic embryo quality could be improved by mating behaviours in mice. To investigate this hypothesis, female mice were mated with vasectomized Kunming white male mice after superovulation. Oocytes were collected and counted at 16 h after superovulation. The oocytes were then artificially activated by medium containing 10 mM strontium chloride and 5 µg/ml cytochalasin B. Blastocysts were obtained by cultivating activated oocytes in vitro. Expression levels of reprogramming transcription factors (i.e. Oct4, Sox2, Klf4 and c-Myc) in oocytes, apoptosis-related genes (i.e. Bax, Bcl2 and c-Myc) in cumulus cells and pluripotency-related transcription factors (i.e. Oct4, Nanog and FGF4) in blastocysts were analysed in samples collected from mated and unmated mice. Additionally, developmental competence of parthenogenetic embryos was used to assess following fibroblast growth factor 4 (FGF4) treatment. The results showed that the formation rate of blastocysts in unmated mice was significantly higher than that in mated mice (p < 0.05). Embryo development was primarily blocked at the eight-cell stage in mated mice; however, the blastocyst formation rate did not differ significantly between groups after the addition of 25 ng/ml FGF4 to the medium at the four-cell stage (p > 0.05). Moreover, the expression of the reprogramming factor Sox2 was significantly different in oocytes collected from mated versus unmated mice. Taken together, our results demonstrated that mating behaviours influenced embryonic development in vitro by decreasing FGF4 expression.

Prefabrication of axial vascularized tissue engineering coral bone by an arteriovenous loop: a better model.

The most important problem for the survival of thick 3-dimensional tissues is the lack of vascularization in the context of bone tissue engineering. In this study, a modified arteriovenous loop (AVL) was developed to prefabricate an axial vascularized tissue engineering coral bone in rabbit, with comparison of the arteriovenous bundle (AVB) model. An arteriovenous fistula between rabbit femoral artery and vein was anastomosed to form an AVL. It was placed in a circular side groove of the coral block. The complex was wrapped with an expanded-polytetrafluoroethylene membrane and implanted beneath inguinal skin. After 2, 4, 6 and 8 weeks, the degree of vascularization was evaluated by India ink perfusion, histological examination, vascular casts, and scanning electron microscopy images of vascular endangium. Newly formed fibrous tissues and vasculature extended over the surfaces and invaded the interspaces of entire coral block. The new blood vessels robustly sprouted from the AVL. Those invaginated cavities in the vascular endangium from scanning electron microscopy indicated vessel's sprouted pores. Above indexes in AVL model are all superior to that in AVB model, indicating that the modified AVL model could more effectively develop vascularization in larger tissue engineering bone.

Synthesis and characterization of organic dyes containing various donors and acceptors.

New organic dyes comprising carbazole, iminodibenzyl, or phenothiazine moieties, respectively, as the electron donors, and cyanoacetic acid or acrylic acid moieties as the electron acceptors/anchoring groups were synthesized and characterized. The influence of heteroatoms on carbazole, iminodibenzyl and phenothiazine donors, and cyano-substitution on the acid acceptor is evidenced by spectral, electrochemical, photovoltaic experiments, and density functional theory calculations. The phenothiazine dyes show solar-energy-to-electricity conversion efficiency (eta) of 3.46-5.53%, whereas carbazole and iminodibenzyl dyes show eta of 2.43% and 3.49%, respectively.

Modified approach to construct a vascularized coral bone in rabbit using an arteriovenous loop.

The most important factor for the survival of thick three-dimensional tissues is the degree of vascularization. In this study, a modified arteriovenous loop (AVL) model was developed to prefabricate an axial vascularized tissue-engineered coral bone. In group A (n = 28), an arteriovenous fistula between rabbit femoral artery and vein was anastomosed to form an AVL. The AVL was placed in a coral block (6 x 8 x 10 mm (3)) as a vascular carrier. The complex was wrapped with polytetrafluoroethylene membrane and implanted subcutaneously. In group B (n = 20), there was no vascular carrier, and the same dimensional coral was directly implanted beneath inguinal skin. After 2, 4, 6, and 8 weeks, the rabbits were perfused with heparinized saline (for scanning electron microscopy), India ink (for histological examination), and ethylene perchloride (for vascular casts) via the abdominal aorta. In group A, histology showed that newly formed vasculature extended over the surfaces and invaded the entire coral blocks. The vascular density was significantly superior to that in group B. Vascular casts showed that new blood vessels robustly sprouted from the AVL. Scanning electron microscopy demonstrated that there were minute sprouting cavities in the vascular endangium. In this model, an axial vascularized coral bone could be effectively constructed.

[Constructing tissue engineered trachea-like cartilage graft in vitro by using bone marrow stromal cells sheet and PLGA internal support: experimental study in bioreactor].

OBJECTIVE: To explore the feasibility of constructing tissue engineered trachea-like cartilage graft in vitro by using bone marrow stromal cells (BMSCs) sheet and PLGA internal support. METHODS: Rabbit BMSCs were expanded and induced by transforming growth factor-1 to improve chondrocyte phenotype of BMSCs. BMSCs sheets were obtained by continuous culture and wrapped the PGLA scaffold in the shape of cylinder. The constructs were incubated in spinner flask for 8 weeks and cartilage formation was investigated by gross inspection, histology, glycosaminoglycan and mechanical strength content. RESULTS: After in vitro culture, cartilage like tissue in cylindrical shape had been regenerated successfully. Stiff, shiny, pearly opalescence tissues were observed. Histological analysis showed engineered trachea cartilage consisted of evenly spaced lacunae embedded in matrix, cells stationed in the lacunae could be noticed clearly. Safranin-O staining on the sections showed homogenous and positive red staining, which demonstrated that the engineered tissue was rich in proteoglycans. CONCLUSIONS: Based on the cell sheet and internal support strategy, trachea-like cartilage in cylindrical shape could be successfully fabricated which provided a highly effective cartilage graft substitute and could be useful in many situations of trachea-cartilage loss encountered in clinical practice.

Traffic and meteorological impacts on near-road air quality: summary of methods and trends from the Raleigh Near-Road Study.

A growing number of epidemiological studies conducted worldwide suggest an increase in the occurrence of adverse health effects in populations living, working, or going to school near major roadways. A study was designed to assess traffic emissions impacts on air quality and particle toxicity near a heavily traveled highway. In an attempt to describe the complex mixture of pollutants and atmospheric transport mechanisms affecting pollutant dispersion in this near-highway environment, several real-time and time-integrated sampling devices measured air quality concentrations at multiple distances and heights from the road. Pollutants analyzed included U.S. Environmental Protection Agency (EPA)-regulated gases, particulate matter (coarse, fine, and ultrafine), and air toxics. Pollutant measurements were synchronized with real-time traffic and meteorological monitoring devices to provide continuous and integrated assessments of the variation of near-road air pollutant concentrations and particle toxicity with changing traffic and environmental conditions, as well as distance from the road. Measurement results demonstrated the temporal and spatial impact of traffic emissions on near-road air quality. The distribution of mobile source emitted gas and particulate pollutants under all wind and traffic conditions indicated a higher proportion of elevated concentrations near the road, suggesting elevated exposures for populations spending significant amounts of time in this microenvironment. Diurnal variations in pollutant concentrations also demonstrated the impact of traffic activity and meteorology on near-road air quality. Time-resolved measurements of multiple pollutants demonstrated that traffic emissions produced a complex mixture of criteria and air toxic pollutants in this microenvironment. These results provide a foundation for future assessments of these data to identify the relationship of traffic activity and meteorology on air quality concentrations and population exposures.

Treatment of alopecia by transplantation of hair follicle stem cells and dermal papilla cells encapsulated in alginate gels.

The affected individual of hair loss demands help, because hair is viewed as a sign of youth and good health. Nowadays treatment of alopecia includes drug therapy and hair transplantation. Some drugs may promote hair growth, at least temporarily, but the treatment is effective only in milder alopecia, instead of extensive alopecia. Furthermore, the side effect of long period medication could not be avoided. Hair transplantation involves harvesting small pieces of hair-bearing scalp grafts from a donor site and relocating them to a bald area. This method does not increase the number of existing hairs, but only redistributes them. The operation is sophisticated and time-consuming, thus the patient suffers a lot during the process. The discovery of hair follicle stem cells (FSC) brings gospel to the affected individual of hair loss because of its capacity of generating new hair when they interact with mesenchymal dermal papilla cells (DPC). Besides, both FSC and DPC have strong proliferative capacity and the patient's own cells could be expanded considerably in vitro. Thus we hypothesize that the microencapsulation of the two kinds of cells in alginate gels could be implanted into the bald scalp of the patient since alginate gels is effective in cell transplantation. The strategy may provide a more convenient and valid alternative to hair loss if the hypothesis proved to be practical.

[The preparation of series of the controllable degradation coral-hydroxyapatite (SCHA-200R) and the on its application as the scaffold in bone tissue-engineering].

OBJECTIVE: Fabricate series of the controllable degradation coral-hydroxyapatite. METHODS: The natural coral undergo a chemical reaction with (NH4)2 HPO4 at high temperature and pressure for different time-lengths. After getting the products, the components and the special structures were analyzed. Observe the biologic degradation of the reaction products and analyze the metal elements and their contents. Haemolysis tests, cytotoxity tests and bone compatibility tests were performed to assess the biocompatibility of the products. RESULTS: When hydrothermal reactions happened under different conditions, the different gradients of CaCO3/hydroxyapatite materials were produced. These types of materials kept the characteristic of interconnected micro-porous network structures. A thin layer of compact material can be seen on the surface of its trabecula ultra-micro structure. The SCHA-200R has a good biocompatibility. CONCLUSIONS: Gradient HA (SCHA-200R) materials can be formed by adjusting the same temperature, same pressure and different time-length of the reaction. This kind of gradient material keeps the quality of micro-porous network structures. The SCHA-200R is a potential candidate scaffold for bone tissue engineering.

Enhancing skin flap survival by a cell-permeable wild-type survivin.

Skin grafts, including skin flaps, are widely used in plastic and reconstructive surgery to cover wounds and tissue defects resulting from mechanic or burn injury. Ischemic necrosis is the main complication in skin graft surgery due to inefficient revascularization. Though the surgical delay procedure has been proved to be the only effective technique to prevent skin flap ischemic necrosis by mechanism of inducing adaption to hypoxia, but it is time consuming, costly, and having high risk of infection due to repeated surgery. Recent research demonstrated that, in addition to protecting cells against apoptosis, the expression of survivin correlates with intratumoral microvessel density in several different types of tumors and survivin could upregulate several proangiogenic factors, including VEGF, Egr-1 and Siah-1. Moreover, Survivin DeltaEx3, one of the survivin alternative splice variants, is necessary for activating the small GTPase Rac1 during endothelial tube formation and required for in vivo endothelial cell invasion. Therefore, we postulate that intracellular delivery of survivin or Survivin DeltaEx3 by fusion with protein transduction domain would enhance skin flap survival through accelerating revascularization by both inhibiting the apoptosis of microvascular endothelial cells and promoting skin flap angiogenesis. If the hypothesis was proved to be practical, the fusion proteins would be widely used in plastic and reconstructive surgery to prevent skin flap from ischemic necrosis in the future.