Conserved odontogenic potential in embryonic dental tissues

Classic tissue recombination studies have demonstrated that, in the early developing mouse tooth germ, the odontogenic potential, known as the tooth-inductive capability, resides initially in the dental epithelium and then shifts to the dental mesenchyme. However, it remains unknown if human embryonic dental tissues also acquire such odontogenic potential. Here we present evidence that human embryonic dental tissues indeed possess similar tooth-inductive capability. We found that human dental epithelium from the cap stage but not the bell stage was able to induce tooth formation when confronted with human embryonic lip mesenchyme. In contrast, human dental mesenchyme from the bell stage but not the cap stage could induce mouse embryonic second-arch epithelium as well as human keratinocyte stem cells, to become enamel-secreting ameloblasts. We showed that neither post-natal human dental pulp stem cells (DPSCs) nor stem cells from human exfoliated deciduous teeth (SHED) possess odontogenic potential or are odontogenic-competent. Our results demonstrate a conservation of odontogenic potential in mouse and human dental tissues during early tooth development, and will have an implication in the future generation of stem-cell-based bioengineered human replacement teeth.

NKG2D blockade significantly attenuates ischemia-reperfusion injury in a cardiac transplantation model

BACKGROUND

NKG2D (natural killer group 2 member D), are activating or coactivating receptor on NK cells, γδ T, and CD8(+) T cells, stimulates cytokine secretion by the former two and plays a costimulatory role for the last CD8(+) T cells.

METHODS

Male Lewis rat hearts were flushed and stored in cold Bretschneider preservation solution for 8 hours. Anti-NKG2D monoclonal antibody (mAb) was administered before transplantation into syngeneic recipients. Expressions of Troponin-T, myeloperoxidase (MPO), tumor necrosis factor (INF), (ICAM) and interleukin (IL)-17 were examined on days 1, 3, and 7 after reperfusion.

RESULTS

We observed that isografts from anti-NKG2D mAb-treated animals showed decreased cardiac troponin-T, low expression of MPO, TNF, and ICAM, and superior cardiac output. Furthermore, blockade of NKG2D significantly reduced the number of γδ T cells, which are the main source of IL-17 production.

CONCLUSION

Blockade of NKG2D significantly attenuated ischemia-reperfusion injury in a cardiac transplantation model. The effect coincided with a low expression of TNFα, ICAM and a reduced number of infiltrating IL-17-producing γδ T cells.

Efficacy and safety of enteric-coated mycophenolate sodium in patients with de novo and maintenance renal transplantation

AIMS

To evaluate the efficacy and safety of enteric-coated mycophenolate sodium (EC-MPS) in renal transplant patients treated de novo and for maintenance.

METHODS

The efficacy and safety data of EC-MPS in renal transplant patients treated de novo and for maintenance in our hospital from July 2009 to March 2013 were reviewed.

RESULTS

Thirty-one patients treated with EC-MPS de novo were included: there were 16 male and 15 female patients. The acute allograft rejection rate was 12.9% (4/31) and pneumonia occurred in 25.8% patients (8/31); the allograft survival rate was 96.7% (30/31) with a patient survival rate of 96.7% (30/31). Gastrointestinal side effects occurred in four patients (12.9%). Only one patient discontinued EC-MPS and treatment was converted to bredinin because of gastrointestinal intolerance. Thirty-nine patients receiving mycophenolate mofetil (MMF) de novo treatment served as a control group. Five (13.2%) of 38 patients developed serious acute rejection and 10 patients (26.3%) had pulmonary infection. Eight (21.1%) patients suffered abdominal distention, diarrhoea and other gastrointestinal adverse reactions; the symptoms improved significantly after treatment change to mizoribine. Compared with the MMF de novo group, the allograft function, blood cell counts and urine protein were similar in the EC-MPS de novo treatment group. The incidence of gastrointestinal side effects was obviously lower in the EC-MPS group than in the MMF group, and there was no difference in serious acute rejection and pulmonary infection between the groups. The study also included 23 renal transplantation maintenance patients who suffered from chronic diarrhoea and treatment was changed to EC-MPS treatment. This change to EC-MPS was at 77 months after transplantation. The gastrointestinal symptoms improved significantly in 21 patients after conversion. Compared with the results at 1 week, no obvious deterioration in serum creatinine, cystatin or estimated glomerular filtration rate was found at 1, 3 and 12 months after the change. In addition, there was no marked decline in blood cell counts and no significant increase in urine protein.

CONCLUSION

The outcome of EC-MPS treatment in clinical practice of de novo kidney transplant patients was good, with high patient and graft survivals. In maintenance patients it induced an improvement in gastrointestinal side effects and a stable allograft function.

Revealing of the transition from n- to p-type conduction of InN:Mg by photoconductivity effect measurement

We report evidence of the transition from n- to p-type conduction of InN with increasing Mg dopant concentration by using photoconductivity (PC) measurement at room temperature. This transition is depicted as a conversion from negative to positive PC under above-bandgap optical excitation. The n- to p-type transition in InN:Mg is further confirmed by thermopower measurements. PC detection method is a bulk effect since the optical absorption of the surface electron accumulation is negligibly low due to its rather small thickness, and thus shows advantage to detect p-type conduction. This technique is certainly helpful to study p-type doping of InN, which is still a subject of discussions.

The FEN1 E359K germline mutation disrupts the FEN1-WRN interaction and FEN1 GEN activity, causing aneuploidy-associated cancers

Polymorphisms and somatic mutations in Flap Endonuclease 1 (FEN1), an essential enzyme involved in DNA replication and repair, can lead to functional deficiencies of the FEN1 protein and a predisposition to cancer. We identified a FEN1 germline mutation which changed residue E359 to K in a patient whose family had a history of breast cancer. We determined that the E359K mutation, which is in the protein-protein domain of FEN1, abolished the interaction of FEN1 with Werner Syndrome protein (WRN), an interaction which is critical for resolving stalled DNA replication forks. Furthermore, although the flap endonuclease activity of FEN1 E359K was unaffected, it failed to resolve bubble structures, which requires the FEN1 gap dependent endonuclease (GEN) activity. To determine the etiological significance of E359K, we established a mouse model containing this mutation. E359K mouse embryonic fibroblasts (MEF) were more sensitive to DNA cross-linking agents that cause replication forks to stall. Cytological analysis suggested that the FEN1-WRN interaction was also required to for telomere stability; mutant cell lines had fragile telomeres, increased numbers of spontaneous chromosomal anomalies and higher frequencies of transformation. Moreover, the incidence of cancer was significantly higher in mice homozygous for FEN1 E359K than in wild-type mice, suggesting that the FEN1 E359K mutation is oncogenic.

Co-culture of spleen stromal cells with bone marrow mononuclear cells leads to the generation of a novel macrophage subset

Macrophages adopt diverse activation states depending on the microenvironment. Recently, stromal cells have been demonstrated to be organizers of the microenvironment. Here, using splenic stromal cells to mimic the splenic microenvironment in vivo, we show that spleen stromal cells can programme bone marrow-derived mononuclear cells to differentiate and polarize into a novel macrophage subset. These differentiated macrophages (Diff-Mφ) exhibited pronounced production of IL-10, IL-6 and TNF-α, but diminished the production of IL-12 in response to LPS. The generation of Diff-Mφ depended on cell-cell contact as well as on soluble factors. Diff-Mφ directly suppressed the antigen-non-specific (CD3/CD28) CD4(+) T cell proliferative response and induced cell death of activated CD4(+) T cells. As for cytokine production in CD4(+) T cells, Diff-Mφ promoted IL-10 and IL-17 production, whereas inhibited IL-4 production and did not alter IFN-γ production. Besides, Diff-Mφ also expressed iNOS, CD16/CD32, CD54, CD43, CCR7, CD44, PD-L1 and FasL, which might be involved in the function of Diff-Mφ. These results suggest that splenic microenvironment may physiologically induce a novel type of macrophages differentiation.

Strategy and long-term outcomes of endovascular treatment for Budd-Chiari syndrome complicated by inferior vena caval thrombosis

OBJECTIVES

The aim of this study was to evaluate the strategy and long-term outcomes of endovascular treatment of Budd-Chiari syndrome (BCS) complicated by inferior vena cava (IVC) thrombosis.

METHODS

The treatment strategy and outcomes of BCS complicated by IVC thrombosis were retrospectively evaluated in a single-center study. The treatment was aimed at the IVC thrombus, not hepatic vein occlusion. All 133 patients with BCS complicated by IVC thrombosis from February 2003 to March 2013 underwent endovascular treatment. For the fresh thrombus group (n=75) recanalization was performed after transcatheter thrombolysis with urokinase. For the mixed thrombus group (n=19) a small balloon pre-dilation of the IVC was performed first, followed by transcatheter thrombolysis using urokinase and a large balloon dilation of the IVC. For the old thrombus group (n=39) a large balloon dilation or/and stent placement was performed directly. Pre- and post-treatment follow-ups were recorded.

RESULTS

The endovascular treatment was successful in 131 out of 133 patients (98.5%). Thirty seven patients had synchronous hepatic vein occlusion. The incidence of serious complications was 4.5% (6/133). Symptomatic pulmonary embolism occurred in three cases, cerebral hemorrhage in two, and cardiac tamponade in one. The cumulative 1-, 5-, and 10-year primary patency rate was 96.3%, 84.0%, and 64.6%, respectively. The cumulative 1-, 5-, and 10-year secondary patency rate was 99.0%, 96.1% and 91.3%, respectively. Segmental occlusion of the IVC and duration of anticoagulant therapy less than 6 months were independent risk factors for reocclusion.

CONCLUSIONS

For patients with BCS complicated by IVC thrombosis, an individualized treatment strategy based on the property of the thrombus can result in excellent long-term patency.

Calumenin-15 facilitates filopodia formation by promoting TGF-β superfamily cytokine GDF-15 transcription

Filopodia, which are actin-rich finger-like membrane protrusions, have an important role in cell migration and tumor metastasis. Here we identify 13 novel calumenin (Calu) isoforms (Calu 3-15) produced by alternative splicing, and find that Calu-15 promotes filopodia formation and cell migration. Calu-15 shuttles between the nucleus and cytoplasm through interacting with importin α, Ran GTPase, and Crm1. The phosphorylation of the threonine at position 73 (Thr-73) by casein kinase 2 (CK2) is essential for the nuclear import of Calu-15, and either Thr-73 mutation or inhibition of CK2 interrupts its nuclear localization. In the nucleus, Calu-15 increases the transcription of growth differentiation factor-15 (GDF-15), a member of the transforming growth factor-β (TGF-β) superfamily, via binding to its promoter region. Furthermore, Calu-15 induces filopodia formation mediated by GDF-15. Together, we identify that Calu-15, a novel isoform of Calu with phosphorylation-dependent nuclear localization, has a critical role in promoting filopodia formation and cell migration by upregulating the GDF-15 transcription.

Hidden T-linear scattering rate in Ba0.6K0.4Fe2As2 revealed by optical spectroscopy

The optical properties of Ba0.6K0.4Fe2As2 have been determined in the normal state for a number of temperatures over a wide frequency range. Two Drude terms, representing two groups of carriers with different scattering rates (1/τ), well describe the real part of the optical conductivity σ1(ω). A "broad" Drude component results in an incoherent background with a T-independent 1/τb, while a "narrow" Drude component reveals a T-linear 1/τn resulting in a resistivity ρn≡1/σ1n(ω→0) also linear in temperature. An arctan(T) low-frequency spectral weight is also strong evidence for a T-linear 1/τ. A comparison to other materials with similar behavior suggests that the T-linear 1/τn and ρn in Ba0.6K0.4Fe2As2 originate from scattering from spin fluctuations and hence that an antiferromagnetic quantum critical point is likely to exist in the superconducting dome.

An animal model of Kashin-Beck disease induced by a low-nutrition diet and exposure to T-2 toxin

OBJECTIVE

We investigated the combined roles of a low-nutrition diet (low levels of protein, iodine, and selenium) and T-2 toxin in bone development and to establish an experimental animal model of Kashin-Beck disease (KBD) that reliably mimics the disease's pathological changes for further study of the pathogenesis and prevention of the disease.

METHODS

Sprague-Dawley rats were randomly divided among four groups: group A, normal diet; group B, normal diet plus T-2 toxin; group C, low-nutrition diet; and group D, low-nutrition diet plus T-2 toxin exposure. The radiographic and histopathological changes in the tibial growth zone, plate cartilage and metaphysis were examined.

RESULTS

In group D, all epiphyseal plates were blurred, thin, and irregular. Tibias were significantly shorter in group D than in groups A and B. After 4 weeks, epiphyseal plates showed chondrocyte necrosis, with the more obvious necrosis appearing in groups C and D. The positive rate of lamellar necrosis was significantly higher in group D than in groups B and A (P < 0.01). In group D, metaphyseal trabecular bone was sparse, disordered, and disrupted, and massive transverse trabecular bone appeared in the metaphysis at 12 weeks.

CONCLUSIONS

A rat model of KBD induced by a low-nutrition diet and T-2 toxin exposure demonstrated radiographic and histopathological abnormalities of the proximal epiphyseal plate and the tibial metaphysis that are very similar to the bone changes found in patients with KBD. This animal model will be helpful for further study of the pathogenesis and prevention of KBD.

Is there reduced polyethylene wear and longer survival when using a mobile-bearing design in total knee replacement?

The purpose of this study was to undertake a meta-analysis to determine whether there is lower polyethylene wear and longer survival when using mobile-bearing implants in total knee replacement when compared with fixed-bearing implants. Of 975 papers identified, 34 trials were eligible for data extraction and meta-analysis comprising 4754 patients (6861 knees). We found no statistically significant differences between the two designs in terms of the incidence of radiolucent lines, osteolysis, aseptic loosening or survival. There is thus currently no evidence to suggest that the use of mobile-bearing designs reduce polyethylene wear and prolong survival after total knee replacement.

Cite this article: Bone Joint J 2013;95-B:1057–63.

Effects of strontium impurity on the structure and dynamics of Al88Si12 liquid

The effects of strontium modification on the structure and dynamics of Al88Si12 liquid are studied by means of ab initio molecular dynamics simulations. By replacing 0.5% and 4.0% of Al with Sr, we show that the addition of Sr lowers the self-diffusion of Al and Si of the liquid and reduces the nearest-neighbor correlation between Si atoms. The simulation provides an explanation for the change in morphology of the eutectic phases observed in rapidly solidified Al-Si alloys modified with Sr.

Magnetic topology changes induced by lower hybrid waves and their profound effect on edge-localized modes in the EAST tokamak

Strong mitigation of edge-localized modes has been observed on Experimental Advanced Superconducting Tokamak, when lower hybrid waves (LHWs) are applied to H-mode plasmas with ion cyclotron resonant heating. This has been demonstrated to be due to the formation of helical current filaments flowing along field lines in the scrape-off layer induced by LHW. This leads to the splitting of the outer divertor strike points during LHWs similar to previous observations with resonant magnetic perturbations. The change in the magnetic topology has been qualitatively modeled by considering helical current filaments in a field-line-tracing code.

Superselective renal artery embolization in the treatment of renal hemorrhage

BACKGROUND

Renal hemorrhage is a potentially life-threatening event that may follow trauma, operation, biopsy, and sudden spontaneous rupture of renal tumors or aneurysms. Superselective renal artery embolization (SRAE) is a well-established method for such cases.

OBJECTIVES

To assess the effectiveness of SRAE in the treatment of renal hemorrhage at our institute.

MATERIALS AND METHODS

We respectively reviewed the medical records of patients who underwent SRAE for renal hemorrhage from January 2005 to June 2012. Data on patients' characteristics, indications, requirement of pre-embolization blood transfusion, angiographic finding, location of bleeding site, embolization agents, post-embolization transfusion requirement, complications and the outcome were recorded.

RESULTS

A total of 46 patients, aged 26-73 years, underwent SRAE because of hemorrhage after percutaneous nephrolithotomy (n = 25), partial nephrectomy (n = 6), renal biopsy (n = 2), trauma (n = 2), rupture of angiomyolipoma (n = 4), renal aneurysm (n = 1), and renal ateriovenous malformations (n = 6). A total of 41 patients (80.8 %) underwent successful embolization. Treatment failed in 5 patients with hemorrhage caused by percutaneous nephrolithotomy. Of these, four patients underwent a secondly superselective embolization and had a successful outcome. The remaining one was managed by conservative therapy with repeated blood transfusions. No patient required nephrectomy to save the life of the patient. No serious procedure-related complications occurred.

CONCLUSIONS

SRAE is an effective and minimal invasive method for the control of renal hemorrhage. Our experience strongly recommended the first-line use of SRAE for severe renal hemorrhage.

Shock-front injector for high-quality laser-plasma acceleration

We report the generation of stable and tunable electron bunches with very low absolute energy spread (ΔE ≈ 5 MeV) accelerated in laser wakefields via injection and trapping at a sharp downward density jump produced by a shock front in a supersonic gas flow. The peak of the highly stable and reproducible electron energy spectrum was tuned over more than 1 order of magnitude, containing a charge of 1-100 pC and a charge per energy interval of more than 10 pC/MeV. Laser-plasma electron acceleration with Ti:sapphire lasers using this novel injection mechanism provides high-quality electron bunches tailored for applications.

Hypoxia differentially regulates human nucleus pulposus and annulus fibrosus cell extracellular matrix production in 3D scaffolds

OBJECTIVE

We hypothesize that intervertebral disc (IVD) cells from distinct region respond differently to oxygen environment, and that IVD cells from patients with disc degeneration can benefit from hypoxia condition. Therefore, we aimed to determine the transcriptional response and extracellular matrix (ECM) production of nucleus pulposus (NP) and annulus fibrosus (AF) cells to different oxygen tension.

METHOD

Human NP and AF from degenerated IVD were seeded in 3D scaffolds and subjected to varying oxygen tension (2% and 20%) for 3 weeks. Changes in ECM were evaluated using quantitative real-time reverse transcriptase polymerase chain reaction, histological and immunohistological analyses.

RESULTS

Hypoxia significantly enhances NP cells phenotype, which resulted in greater production of sulfated glycosaminoglycan (GAG) and collagen type II within the constructs and the cells expressed higher levels of genes encoding NP ECM. A significantly stronger fluorescent signal for hypoxia-inducible factor (HIF-1α) as also found in the NP cells under the hypoxic than normoxic condition. However, there was little effect of hypoxia on the AF cells.

CONCLUSIONS

The NP and AF cells respond differently to hypoxia condition on the 3D scaffold, and hypoxia could enhance NP phenotype. When used in concert with appropriate scaffold material, human NP cells from degenerated disc could be regenerated for tissue engineering application.

Diagnosis and management of Crohn's disease of the ileal pouch

Approximately 20-30% of patients with ulcerative colitis would eventually require surgery despite recent advances in medical therapy. Ileal pouch-anal anastomosis has become the surgical treatment of choice after total proctocolectomy. A subset of patients who had a preoperative diagnosis of ulcerative colitis may develop Crohn's disease or a Crohn's disease-like condition of the ileal pouch after surgery. Diagnosis, differential diagnosis, and management of Crohn's disease of the ileal pouch have been challenging. A combined approach with the assessment of clinical history, endoscopy, histology, abdominal/pelvic imaging, and examination under anesthesia is necessary for an accurate diagnosis, disease classification, management and improvement in outcome. A multidisciplinary approach with gastroenterologists, colorectal surgeons, gastrointestinal pathologists and radiologists for proper medical, endoscopic, and surgical treatment is advocated.

The impact of ulcerative colitis on the long-term outcome of patients with primary sclerosing cholangitis

BACKGROUND

The impact of ulcerative colitis (UC) on the outcome of primary sclerosing cholangitis (PSC) outcome remains unclear.

AIM

To investigate whether the presence of UC is associated with a worse clinical of associated PSC.

METHODS

A total of 222 patients with PSC (167 with UC and 55 without UC) seen and followed at a single centre from 1985 to 2011 were included. Clinical and demographic variables were obtained and patients were followed until the date of their last clinic visit.

RESULTS

The median age at presentation of PSC with associated UC was 38 vs. 47 years without UC (P < 0.001). At presentation, median serum bilirubin (2.1 vs. 4.5, P < 0.001) and the Mayo PSC Risk Score (0.95 vs. 1.69, P < 0.001) were lower in those with UC vs. those without UC. A total of 55 of 167 (32.9%) patients with PSC-UC developed colon neoplasia in contrast to 1 of the 55 (1.8%) patients with PSC. (P < 0.001) On proportional hazards analysis, UC (hazard ratio (HR) = 0.90 [95% confidence interval (CI): 0.60-1.34, P = 0.60] was not associated with death or orthotopic liver transplantation (OLT), when adjusting for gender, Mayo risk score and year of PSC diagnosis; whereas the revised Mayo risk score [HR = 5.08, 95% CI: (2.62-9.86), P < 0.001] was associated with a greater risk of OLT or death.

CONCLUSIONS

Primary sclerosing cholangitis often is recognised at an early stage in patients with concurrent ulcerative colitis; ulcerative colitis has no impact on long-term prognosis in terms of liver-related outcomes when adjusted for the severity of liver disease.

Diagnostic yield of colonoscopy for constipation as the sole indication

AIM

There is controversy over whether constipation as the only symptom should be an indication for routine diagnostic colonoscopy. The study was carried out to assess the prevalence of abnormal pathology on colonoscopy and to assess the risk factors for colonic neoplasia in patients with constipation but without 'high risk symptoms'.

METHOD

A cross-sectional, single-centre study was conducted on individuals who underwent colonoscopy for constipation as the sole indication between 2005 and 2008. Standardized endoscopic and pathology reports were reviewed. Univariable and multivariable analyses were performed.

RESULTS

A total of 786 patients (595 women, 75.7%; mean age, 57.4±13.5 years) underwent diagnostic colonoscopy for constipation. Forty-three (5.5%) had polyps, of whom 19 (2.4%) had hyperplastic polyps and 19 (2.4%) adenomas. No cancers were found. In patients with adenoma, the detection rate was 2.9% for patients below age 40 years and 1.7% for patients below age 50 years. Older age was associated with a polyp in both univariate and multivariate analysis. Gender, ethnicity and smoking were not associated with polyp or adenoma.

CONCLUSION

Colonoscopy for patients with constipation as the sole indication had a lower yield of neoplastic lesions than that for patients undergoing routine screening colonoscopy. Colonoscopy in constipation may only be warranted in patients who are over 50 years of age.

Preventive effects of supplemental selenium and selenium plus iodine on bone and cartilage development in rats fed with diet from Kashin-Beck disease endemic area

The purpose of this study was to investigate the effects of supplemental selenium and selenium plus iodine on bone and growth plate cartilage histology and serum biochemistic parameters in rats. Ninety-six Wistar rats were randomly divided into the following four groups: group A, the rats fed with normal diet; group B, fed with diet from Kashin-Beck disease (KBD) endemic area; group C, fed with diet from KBD endemic area supplemented with selenium; and group D, fed with diet from KBD endemic area supplemented with selenium and iodine. After 4, 8, and 12 weeks, bone and cartilage samples were collected from the rats and were examined for morphological changes in the tibial growth zone and for changes in the plate cartilage and metaphysic. Compared to the rats fed with diet from the KBD endemic area, the rats fed with the supplemental selenium or selenium plus iodine exhibited diminished necrosis of the chondrocytes in the growth plate. In the groups of rats receiving supplemental selenium and selenium plus iodine, the bone volume/tissue volume ratio (BV/TV), the trabecular thickness (Tb.Th), and the trabecular number were increased, while the trabecular separation was decreased. In the 12th week of the experiment, BV/TV and Tb.Th were significantly increased in the selenium plus iodine group compared to the selenium group. It is concluded that feeding the diet from the KBD endemic area caused necrosis of chondrocytes and dysfunctions of bone development similar to the pathological changes that are seen in KBD. Selenium and iodine protected chondrocytes in growth plate and promoted the formation of trabecular bone. The effects of selenium plus iodine on bone formation were more obvious than those of selenium alone.