[Influence of trabecular microstructure modeling on finite element analysis of dental implant]

OBJECTIVE

To analyze the influence of trabecular microstructure modeling on the biomechanical distribution of implant-bone interface with a three-dimensional finite element mandible model of trabecular structure.

METHODS

Dental implants were embeded in the mandibles of a beagle dog. After three months of the implant installation, the mandibles with dental implants were harvested and scaned by micro-CT and cone-beam CT. Two three-dimensional finite element mandible models, trabecular microstructure(precise model) and macrostructure(simplified model), were built. The values of stress and strain of implant-bone interface were calculated using the software of Ansys 14.0.

RESULTS

Compared with the simplified model, the precise models' average values of the implant bone interface stress increased obviously and its maximum values did not change greatly. The maximum values of quivalent stress of the precise models were 80% and 110% of the simplified model and the average values were 170% and 290% of simplified model. The maximum and average values of equivalent strain of precise models were obviously decreased, and the maximum values of the equivalent effect strain were 17% and 26% of simplified model and the average ones were 21% and 16% of simplified model respectively. Stress and strain concentrations at implant-bone interface were obvious in the simplified model. However, the distributions of stress and strain were uniform in the precise model.

CONCLUSIONS

The precise model has significant effect on the distribution of stress and strain at implant-bone interface.

Bone mesenchymal stem cells improve pregnancy outcome by inducing maternal tolerance to the allogeneic fetus in abortion-prone matings in mouse

INTRODUCTION

The successful pregnancy depends on maternal immune tolerance against the fetus. It has been reported that MSCs (mesenchymal stem cells) could play a regulatory role on immune cells such as CD4⁺T cells, macrophages and NK cells, but their effect on recurrent miscarriage is unknown.

STUDY DESIGN

In a prospective study, the abortion-prone (CBA/J × DBA/2) H-2^d × H-2^k mice were utilized. Female CBA/J mice (8-10 weeks old) were injected with vehicle or MSCs via tail vein or uterine horns, and 14 days later, they were mated with DBA/2 males for the following experiments.

RESULTS

Comparing with the control group, the embryo resorption rate in MSCs-horn injection group was dramatically decreased. MSCs were mainly located at the maternal-fetal interface, indicating that the reduction of resorption rate was due to MSCs' local effect. No matter which treatment was given, there was no significant difference in the levels of IL-4, IL-10, TNF-α and IFN-γ in CD4⁺T cells and IL-10 and IL-12 in macrophages in spleens among each group. However, in contrast to other groups, the levels of IL-4 and IL-10 in CD4⁺T cells localized at the maternal-fetal interface in MSCs-horn injection group were dramatically increased, and TNF-α and IFN-γ levels were notably decreased. While IL-10 expressed in macrophages was obviously higher than other groups and IL-12 in macrophages was significantly lower than other groups.

CONCLUSIONS

The findings indicate that MSCs injection through uterine horns could decrease embryo resorption rate.

L-proline: a highly effective cryoprotectant for mouse oocyte vitrification

Recent studies have shown that L-proline is a natural osmoprotectant and an antioxidant to protect cells from injuries such as that caused by freezing and thawing in many species including plant, ram sperm and human endothelial cells. Nevertheless, this nontoxic cryoprotectant has not yet been applied to mammalian oocyte vitrification. In this study we evaluated the efficiency and safety of the new cryoprotectant in oocyte vitrification. The results indicated that L-proline improves the survival rate of vitrified oocytes, protects mitochondrial functions and could be applied as a new cryoprotectant in mouse oocyte vitrification.

Genetic diversity in fragmented populations of Populus talassica inferred from microsatellites: implications for conservation

Populus talassica Kom. is an ecologically important species endemic to central Asia. In China, its main distribution is restricted to the Ili region in the Xinjiang Autonomous Region. An understanding of genetic diversity and population structure is crucial for the development of a feasible conservation strategy. Twenty-six high-level simple sequence repeat (SSR) markers were screened and used to genotype 220 individuals from three native populations. A high level of genetic diversity and low population differentiation were revealed. We identified 163 alleles, with a mean of 6.269 alleles per locus. The observed and expected heterozygosities ranged from 0.472 to 0.485 (with a mean of 0.477), and from 0.548 to 0.591 (mean 0.569), respectively. Analysis of molecular variance revealed 93% variation within populations and 7% among populations. A model-based population structure analysis divided P. talassica into two groups (optimal K = 2). These genetic data provide crucial insight for conservation management.

Clinical Evaluation of Human Umbilical Cord Mesenchymal Stem Cell Transplantation After Angioplasty for Diabetic Foot

Aims: The multilineage differentiation potential of human umbilical cord mesenchymal stem cells (HUCMSCs) holds therapeutic promise for non-healing ulcers and tissue regeneration. The present study evaluated the effects of HUCMSC transplantation after angioplasty for treatment of diabetic foot. Methods: Included in the study were 53 patients (72 limbs) with severe symptoms of Fontaine II-IV diabetic foot accompanied by varying degrees of lower extremity arterial disease. The patients were randomly apportioned to a control group (25 patients; 38 limbs) or an experimental group (28 patients; 34 limbs). Patients of both groups received interventional treatment with angioplasty; those in the experimental group also received HUCMSCs by endovascular infusion and injection around the foot ulcer. Results: Within the 3-month follow-up, relative to patients in the control group, those in the experimental group experienced significantly greater and more stable improvements in skin temperature, ankle-brachial pressure index, transcutaneous oxygen tension, and claudication distance. Notably, 3 months after treatment a significant increase in neovessels, accompanied by complete or gradual ulcer healing, was shown in the experimental group. In addition, no serious complications or adverse reactions were associated with the treatment. Conclusion: Therefore, our results indicate that HUCMSC transplantation after angioplasty is a safe and effective clinical therapy for severe diabetic foot.

Latitudinal distributions of activities in atmospheric aerosols, deposition fluxes, and soil inventories of ⁷Be in the East Asian monsoon zone

Activities of atmospheric aerosols, bulk deposition fluxes, and undisturbed soil inventories of (7)Be were investigated in China's East Asian monsoon zone at various latitudes ranging from 23.8°N to 43.5°N. The annual latitudinal distributions of (7)Be concentrations in aerosols follow a distribution pattern which looks similar to a normal distribution with the maxima occurring in the mid-latitude region. Simultaneous measurements of (7)Be at various latitudes suggest that atmospheric circulation may play an important role in the latitudinal distributions of (7)Be in surface air. Latitude and wet precipitation are the main factors controlling the bulk (7)Be depositional fluxes. Significant seasonal variations in (7)Be depositional fluxes in Beijing, a mid-latitude city, were observed with the highest flux in summer and the lowest in winter, whereas less seasonality were found in the high- and the low-latitude cities. The highest (7)Be inventory in undisturbed soils in summer also occurred at a mid-latitudinal area in the East Asian monsoon zone. Precipitation is the main factor controlling the (7)Be soil inventory in Qingdao with the highest values occurring in autumn followed by summer.

Microvascular remodeling of nasal mucosa in allergic rhinitis induced by an allergen in Sprague-Dawley rats

This study aimed to observe microvascular changes in the nasal mucosa of Sprague-Dawley (SD) rats with allergic rhinitis (AR) after persistent exposure to an allergen with fluticasone propionate (FP) treatment. Ninety healthy SD rats were randomly distributed into the control group (A, N = 30), the group with continued exposure to an allergen (B, N = 30), and FP treatment group (C, N = 30). The animals of the persistence group were subjected to persistent exposure to an allergen after 7 weeks of modeling of ovalbumin (OVA) provocation in the nasal mucosa for 16 weeks. At the 8th, 12th, and 16th week after OVA provocation, each group was euthanized at each time point: the FP treatment after OVA provocation, and animals of the control group were not stimulated with OVA and were sacrificed at the same time point. The nasal mucosa of 5 animals from each group was analyzed for the expression of vascular endothelial growth factor (VEGF), and another 5 animals were used to make micro vascular corrosion casts for a scanning electron microscope. The results demonstrate that FP has a strong inhibitory effect on angiogenesis in AR. Inhalation of FP had an antiangiogenic effect through inhibition of VEGF expression but does not completely reverse the remodeling of the nasal mucosa in the short term nor does it have complete control over the expression of VEGF mRNA.

Cytotoxic rotenoid glycosides from the seeds of Amorpha fruticosa

Four new rotenoid glycosides, namely amorphaside A-D (1-4), along with four known ones (5-8) were isolated from the seeds of Amorpha fruticosa. Their chemical structures and absolute configurations were elucidated by HRESIMS, NMR and CD spectra, as well as deduction from biosynthesis route. The sugar units were determined by acid hydrolysis, appropriate derivatization and HPLC analysis. The in vitro anti-proliferative activities of all compounds were evaluated against MCF-7 and HCT-116 cell lines. The results showed that compounds 1-3 had no effect on cell proliferation in the two cell lines even with the concentration of 50 μM, and compounds 4, 7 and 8 had selective cytotoxicity against MCF-7 with IC50 values of 3.90, 0.95 and 34.08 μM, respectively, while compounds 5 and 6 both showed significant cytotoxicity to the two cell lines with IC50 values less than 2.00 μM, even better than the positive control cisplatin. These preliminary results indicated that compounds 5 and 6 might be valuable to anticancer drug candidates.

Gonadotropin-mediated dynamic alterations during bovine oocyte maturation in vitro

Gonadotropins have been widely used in human-assisted reproduction and animal science for the past four decades. However, the effects of gonadotropins on oocyte maturation at the molecular and biochemical levels are poorly understood. To determine the effects of gonadotropins (recombinant follicle stimulating hormone and urinary human menopausal gonadotropin) on oocyte maturation, we used the bovine oocyte in vitro maturation model. First, we studied the effects of increasing gonadotropin concentrations on nuclear maturation and mitochondrial function in oocytes. Gonadotropins at concentrations of 0.075 and 0.75 IU/ml improved nuclear maturation and increased inner mitochondrial membrane potential and ATP levels; however, there were no beneficial effects at concentrations of 7.5 and 75 IU/ml. Second, we studied the effects of increasing gonadotropin concentrations on the status of methylation in matured (MII) oocytes. Aberrant methylation and demethylation of H19, SNRPN, and PEG3 genes were observed in MII oocytes at all concentrations except 0.075 IU/ml. The expression of genes that function in spindle formation, cell cycle control, and methylation was also downregulated by high gonadotropin concentrations. In conclusion, we established the optimal gonadotropin concentration (i.e., 0.075 IU/ml) to be used for bovine oocyte in vitro maturation studies. These results may provide a guide for clinical stimulation protocols and help to reduce the risks associated with gonadotropin administration during in vitro fertilization treatment.

Advances in preimplantation genetic diagnosis/screening

Preimplantation genetic diagnosis (PGD) gives couples who have a high risk of transmitting genetic disorders to their baby the chance to have a healthy offspring through embryo genetic analysis and selection. Preimplantation genetic screening (PGS) is an effective method to select euploid embryos that may prevent repeated implantation failure or miscarriage. However, how and to whom PGS should be provided is a controversial topic. The first successful case of PGD of a human being was reported in 1990, and there have been tremendous improvements in this technology since then. Both embryo biopsy and genetic technologies have been improved dramatically, which increase the accuracy and expand the indications of PGD/PGS.

ART do not increase the risk of Y-chromosome microdeletion in 19 candidate genes at AZF regions

Y-chromosome microdeletions (YCMs) have been found at a much higher rate in infertile men than fertile controls. A specific deletion in the azoospermia factor locus (AZF) at Yq11 is significantly associated with male infertility. Whether assisted reproductive technology (ART) increases the risk of YCM in ART-derived offspring remains unclear. In this study the occurrence of YCM in 199 fathers and their 228 sons (Chinese, Han ethnicity), including 85 offspring conceived by IVF, 73 by intra-cytoplasmic sperm injection (ICSI) and 70 by natural conception, was investigated. Nineteen candidate genes related to YCM were analysed by multiplex ligation-dependent probe amplification. We identified one de novo YCM from 70 naturally-conceived offspring and none from 158 ART-conceived offspring and found no statistical significance between these two groups. There was no statistically-significant difference in the detection rate of the father’s Y-chromosome microdeletion group: IVF 10.7% (8/75), ICSI 3.2% (2/63), natural conception 8.2% (5/61). These results suggest that ART does not increase the risk of YCM in male offspring.

Comparison of 16S rRNA gene PCR and blood culture for diagnosis of neonatal sepsis

Septicemia is a common cause of morbidity and mortality among newborns in the developing world. However, accurate clinical diagnosis of neonatal sepsis is often difficult because symptoms and signs are often nonspecific. Blood culture has been the gold standard for confirmation of the diagnosis. However, the sensitivity is low and results are usually not promptly obtained. Therefore, the diagnosis of sepsis is often based on clinical signs in association with laboratory tests such as platelets count, immature/total neutrophils ratio (I/T), and a rise in C-reactive protein (CRP). Polymerase chain reaction (PCR) methods for the detection of neonatal sepsis represent new diagnostic tools for the early identification of pathogens.

METHODS

During a 4-month prospective study, 16S rRNA PCR was compared with conventional blood culture for the diagnosis of neonatal bacterial sepsis. In addition, the relationship between known risk factors, clinical signs, laboratory parameters, and the diagnosis of sepsis was considered.

RESULTS

Sepsis was suspected in 706 infants from the intensive neonatal care unit. They all were included in the study. The number of positive cultures and positive PCR results were 95 (13.5%) and 123 (17.4%), respectively. Compared with blood culture, the diagnosis of bacterial sepsis by PCR revealed a 100.0% sensitivity, 95.4% specificity, 77.2% positive predictive value, and 100.0% negative predictive value. In this study, Apgar scores at 5 min, weight, icterus, irritability, feeding difficulties, gestational age (GA), premature rupture of membrane (PRM), platelets count, I/T, and a marked rise in CRP were important in establishing the diagnosis of sepsis in the newborn. In addition, weight, GA, PRM, irritability, duration of antibiotic usage, mortality rate, and number of purulent meningitis cases were significantly different between early-onset sepsis and late-onset sepsis.

CONCLUSION

16S rRNA PCR increased the sensitivity in detecting bacterial DNA in newborns with signs of sepsis, allowed a rapid detection of the pathogens, and led to shorter antibiotic courses. However, uncertainty about the bacterial cause of sepsis was not reduced by this method. 16S rRNA PCR needs to be further developed and improved. Blood culture is currently irreplaceable, since pure isolates are essential for antimicrobial drug susceptibility testing.

Stimulation of insulin secretion by large-dose oral arginine administration in healthy adults

The effects of large-dose oral arginine administration on the secretion of insulin by islet β-cells in healthy adults were determined. Eight non-obese healthy volunteers with normal glucose tolerance participated randomly in tests with four stages (with an interval of at least 3 days): the 300 ml purified water stage (PWS), the 75 g glucose stage (GSS), the 30 g arginine stage (ARS) and the 75 g glucose with 30 g arginine stage (GAS). Venous blood samples were collected to detect the concentrations of glucose and insulin at baseline (0) and at 15, 30, 45, 60 and 120 min after drug administration. The glucose and insulin levels were steady in the PWS. The remaining three stages had similarly shaped insulin concentration-time curves, which differed from that of the PWS. The peak concentration of blood insulin and the net incremental area under the curve of blood insulin in the GSS, ARS and GAS were significantly higher compared with those in the PWS (P<0.05). In the ARS, the glucose levels remained stable; however, the net incremental area under the curve for blood insulin in the ARS was much lower compared with that in the GSS or GAS (P<0.05). Large-dose oral arginine administration may slightly stimulate insulin secretion by islet β-cells in healthy adults with normal glucose tolerance in a manner that is independent of glucose concentration.

A novel mutation of the DSRAD gene in a Chinese family with dyschromatosis symmetrica hereditaria

Dyschromatosis symmetrica hereditaria (DSH) is an autosomal dominant cutaneous disorder, characterized by a mixture of hyperpigmented and hypopigmented macules mostly on the dorsal portions of the extremities. Pathogenic mutations have been identified in the double-stranded RNA-specific adenosine deaminase (DSRAD) gene. We studied a Chinese family that included four affected individuals with DSH phenotypes. PCR and direct sequencing were carried out to detect the entire coding region and exon-intron boundaries of the DSRAD gene. A novel nucleotide c.3002G>T missense mutation in the exon 11 of the DSRAD gene was detected in the proband and his father. This information expands the database on DSRAD gene mutations associated with DSH.

[Removal technology of typical odorant in drinking water]

To eliminate the odor in drinking water of one City in China, a study was performed on the typical odorant removal technology and removal processes. Its results showed that as typical odorants, ethanethiol was effectively removed by oxidation and geosmin and 2-MIB were removed by both oxidation and adsorption, but geosmin and 2-MIB's adsorption effect was better than oxidation. When thiol and thioether in raw water was less than 20 microg/L, furthermore, there was not any other odorant, potassium permanganate oxidation should be equipped with enhanced coagulations. When geosmin and 2-MIB in raw was less than 30 ng/L, activated carbon adsorption should be equipped with enhanced coagulations. When thiol and thioether in raw water was more than 20 microg/L, or geosmin and 2-MIB was more than 30 ng/L, ozone-activated carbon process should be added after the conventional water treatment process. When thiol and thioether in raw water was more than 150 microg/L, or geosmin and 2-MIB was more than 100 ng/L, preoxidation or adsorption of powder activated carbon at intake should be combined with ozone-activated carbon according to the odorant composing.

Effect of oxygen content on the transport properties of LaTiO(3+β/2) thin films

The structural and transport properties of LaTiO(3+β/2) epitaxial thin films, grown at different oxygen pressures ranging from 6.6 × 10(-4) to 5 Pa, have been investigated. X-ray diffraction peaks of the films shift to lower angles with increasing oxygen pressure, indicative of a variation of the corresponding lattice spacing. All the films show T(2) dependence of resistivity over a large temperature range of ∼200 K, suggesting a band-filling-induced metallic Fermi-liquid behaviour. Upturns in resistivity have been revealed at low temperatures, which could be ascribed to the Anderson-localization effect caused by the cation vacancies. Furthermore, for the thin films grown at high oxygen pressures of 0.5 and 5 Pa, the dependence of resistivity on temperature shows a maximum at high temperatures. The maximum seems to support the argument that transition between t-orbital ordering and disordering plays an important role in dominating transport properties at high temperatures. Carrier density deduced from Hall coefficient increases with the decrease of oxygen content, and shows strong temperature dependence. From the experimental data, it can be asserted that in the LaTiO(3+β/2) thin films, besides the band filling effect, localization or disorder caused by La and Ti vacancy effects controls the unique transport properties.

The survival and value of liver transplantation for liver carcinoma: a single-center experience

Liver transplantation for liver carcinoma with cirrhosis is a treatment still in dispute. The objectives were to summarize the survival and cost of 50 liver transplant cases performed for liver carcinoma over nearly 3 years.

METHODS

We performed 138 liver transplants from January 1999 to February 2002. There were 50 cases (36.2%) of liver carcinoma with HBV cirrhosis, which were divided into three stages based on the tumor pathology: Stage 1 cases showed a single mass (< or = 5 cm), 4 cases; Stage 2, a single mass > 5 cm or intrahepatic multiple masses without PV cancer embolus, 32 cases; and Stage 3: tumor invasion of the PV or perihepatic lymph nodes or organs, 14 cases. All patients received three to six courses of chemotherapy postoperatively.

RESULTS

All four cases of stage 1 survived > 1 year; one of them is at 3 years with good liver function and tumor free. The mean half-year medical cost was $27.100 +/- 108 in stage 1. The half-year survival and medical costs were 62.5% and $31,500 +/- 260 in stage 2 and 15.0% and $35,500 +/- 134 in stage 3.

CONCLUSION

Liver transplantation is an effective treatment for early-stage liver carcinoma, that achieves good medical and economic results, but should be limited to advanced liver cancer.

Prolonged heart allograft survival resulted from donor-specific T-cell sequestering and removal by selective splenectomy in mice

INTRODUCTION

Selective splenectomy when donor antigen-specific activated T cells are sequestered in the recipient spleen may prolong allograft survival because of removal of all of these T cells.

OBJECTIVES

We investigated the effect on cardiac allograft survival in mice by means of removal of activated specific T cells by splenectomy.

METHODS

Donor (Balb/c) spleen cells were injected into primed allogeneic recipients (C57BL/6). Selective recipient splenectomy and donor-type cervical heart grafting in Balb/c to C57BL/6 from mice were examined at 0, 24, 48, and 72 hours after donor spleen cell infusion.

RESULTS

Control C57BL/6 mice rejected Balb/c heart grafts at 6.86 +/- 0.19 days. Delayed heart grafting plus splenectomy at 24 or 48 hours after donor-type spleen cell infusion significantly prolonged heart allograft survival (24 hours: 15.86 +/- 3.44 days, P < .001; 48 hours: 21.71 +/- 5.22 days, P < .001, respectively). However, 72-hour delayed heart grafting plus splenectomy failed to prevent acute rejection (72 hours: 9.57 +/- 2.51 days, P > .01). Immunohistochemistry showed, at 24 to 48 hours after donor antigen infusion, the recipient spleens characterized by an obvious increase in CD4+ CD8+ T cells in periateriolar lymphoid sheaths, marginal zones, and red pulp compared with the 72-hour group.

CONCLUSIONS

Transient accumulation of donor-specific activated T cells in the spleen of recipients provide an opportunity to remove all of these T cells by a surgical procedure. As the largest immune organ the spleen is the main place where T cells are activated and regenerated. At 24 or 48 hours when donor-specific T cells were sequestered in the spleen after donor antigen stimulation, selective recipient splenectomy was able to remove the T cells and prolong was allograft survival. Refinement of this protocol may eventually warrant clinical application.

Study of a mathematical model of metal ion complexes in solvent sublation

Separation of metal ion complex, [(C(12)H(8)N(2))(3)Fe(2+)], with surfactant sodium dodecylphrate (DLS) complex from aqueous phase was carried out by solvent sublation, which obeys first-order kinetics. On the base of the complete transport mechanisms, the Langmuir adsorption, and the ion complex equilibrium in the aqueous phase, a mathematical model for the [(C(12)H(8)N(2))(3)Fe(2+)]-surfactant ion complex is obtained with the aid of the Mathematic 4.0 program, 4th Runge-Kutta method, and the Matlab programs. The effects of many parameters, such as K(a), K(l), K(ow), d(i), V(o), V(w), and Q(a), on solvent sublation are investigated. Furthermore, the simulation showed that the model is substantiated for experiments on the solvent sublation of the complex.

Effect of Chinese herb Shuangjiawuling on expression of TIMPs in rat with liver fibrosis

AIM: To explore the effect of Chinese herb Shuangjiawuling in preventing hepatic fibrosis in rat with liver fibrosis.

METHODS: Rat immunogenic liver fibrosis model was induced by administration human serum albumin (HSA 200 g/L) intravenously, 80 rats were randomly divided into 5 groups. Shuangjiawuling was taken orally simultaneously with (group A), immediately after (group B), or 3 months after (group C) administration of HAS intravenously. Colchine tablets were taken orally with the administration of HAS (group D), normal rats were used as control (Group E). The pathological changes of liver tissue were observed by HE and Von-Gieson staining. The hepatic mRNA and protein of TIMP-1 and TIMP-2 were analyzed by in site hybridization and immunohistochemistry.

RESULTS: Hepatic fibrosis developed gradually and became obviously on the third month after administration of HAS. And strong expressions of TIMP-1 and TIMP-2 were observed, however, its expression and hepatic fibrosis were reduced dramatically following administration of Shuangjiawuling and colchine tablets. The effect of Shuangjiawuling in preventing fibrosis was superior to that of colchine tablets (P<0.05), and its effect in group A, B, and C decreased in order.

CONCLUSION: Chinese herb Shuangjiawuling can inhibit the development of hepatic fibrosis and the expression of TIMPs, and promoted the effect of the degradation of the extracellular matrix.

Magnetic resonance studies of brain function and neurochemistry

In the short time since its introduction, magnetic resonance imaging (MRI) has rapidly evolved to become an indispensable tool for clinical diagnosis and biomedical research. Recently, this methodology has been successfully used for the acquisition of functional, physiological, and biochemical information in intact systems, particularly in the human body. The ability to map areas of altered neuronal activity in the brain, often referred to as functional magnetic resonance imaging (fMRI), is probably one of the most significant recent achievements that rely on this methodology. This development has permitted the examination of functional specialization in human and animal brains with unprecedented spatial resolution, as demonstrated by mapping at the level of orientation and ocular dominance columns in the visual cortex. These functional imaging studies are complemented by the ability to study neurochemistry using magnetic resonance spectroscopy, allowing the determination of metabolic processes that support neurotransmission and neurotransmission rates themselves.