Neural regulation in tooth regeneration of Ambystoma mexicanum

The presence of nerves is an important factor in successful organ regeneration in amphibians. The Mexican salamander, Ambystoma mexicanum, is able to regenerate limbs, tail, and gills when nerves are present. However, the nerve-dependency of tooth regeneration has not been evaluated. Here, we reevaluated tooth regeneration processes in axolotls using a three-dimensional reconstitution method called CoMBI and found that tooth regeneration is nerve-dependent although the dentary bone is independent of nerve presence. The induction and invagination of the dental lamina were delayed by denervation. Exogenous Fgf2, Fgf8, and Bmp7 expression could induce tooth placodes even in the denervated mandible. Our results suggest that the role of nerves is conserved and that Fgf+Bmp signals play key roles in axolotl organ-level regeneration. The presence of nerves is an important factor in successful organ regeneration in amphibians. The Mexican salamander, Ambystoma mexicanum, is able to regenerate limbs, tail, and gills when nerves are present. However, the nervedependency of tooth regeneration has not been evaluated. Here, we reevaluated tooth regeneration processes in axolotls using a three-dimensional reconstitution method called CoMBI and found that tooth regeneration is nerve-dependent although the dentary bone is independent of nerve presence. The induction and invagination of the dental lamina were delayed by denervation. Exogenous Fgf2, Fgf8, and Bmp7 expression could induce tooth placodes even in the denervated mandible. Our results suggest that the role of nerves is conserved and that Fgf+Bmp signals play key roles in axolotl organ-level regeneration

Radiation hardness testing of an organic liquid scintillator detector for use in high dose rate accident response scenarios

Organic liquid scintillation detectors offer the advantage relative to many alternatives that they are sensitive to both fast neutrons and gamma rays, whilst radiation type can be discerned on the basis of pulse-shape discrimination. Mixed radiation fields of this type can arise in the context of reactor accidents via, for example, 137Cs (gamma) and 244Cm (neutrons). However, performance degradation of such scintillators, such as EJ-301, is a significant possibility that might limit the use of this technology in accident response applications. The premise behind the high dose rate testing of such a liquid scintillator described in this paper is for fuel debris characterisation at Fukushima Daiichi, which has expected dose rates of up to 1000 Gy/hr in close proximity to fuel debris. The tests carried out for this investigation involved using the 60Co gamma irradiation facility at the Dalton Cumbria Facility, Cumbria, United Kingdom to expose the detector to a similar dose rate to that which is estimated within the primary containment vessel for survivability tests. Radiation hardness tests have rarely been reported for such devices and it is expected that the performance will be dependent on the survival of the window of the photomultiplier tube rather than the liquid scintillant itself. A major advantage of the use of this detector is its physical size, due to the limitations on access into Fukushima reactors physical space is a premium. The research described in this paper presents the results of the dose rate exposure of the detector before signal was lost with the total dose observed providing information on any degradation affecting the performance of the device post-irradiatio

Stepwise development of Hematopoietic stem Cells from Embryonic Stem Cells

The cellular ontogeny of hematopoietic stem cells (HSCs) remains poorly understood because their isolation from and their identification in early developing small embryos are difficult. We attempted to dissect early developmental stages of HSCs using an in vitro mouse embryonic stem cell (ESC) differentiation system combined with inducible HOXB4 expression. Here we report the identification of pre-HSCs and an embryonic type of HSCs (embryonic HSCs) as intermediate cells between ESCs and HSCs. Both pre-HSCs and embryonic HSCs were isolated by their c-Kit(+)CD41(+)CD45(−) phenotype. Pre-HSCs did not engraft in irradiated adult mice. After co-culture with OP9 stromal cells and conditional expression of HOXB4, pre-HSCs gave rise to embryonic HSCs capable of engraftment and long-term reconstitution in irradiated adult mice. Blast colony assays revealed that most hemangioblast activity was detected apart from the pre-HSC population, implying the early divergence of pre-HSCs from hemangioblasts. Gene expression profiling suggests that a particular set of transcripts closely associated with adult HSCs is involved in the transition of pre-HSC to embryonic HSCs. We propose an HSC developmental model in which pre-HSCs and embryonic HSCs sequentially give rise to adult types of HSCs in a stepwise manner

Juvenile Granulosa Cell Tumor with Elevated Peripheral Interleukin-6 Level Shows Prolonged Fever and Delayed Puberty

Juvenile granulosa cell tumor (JGCT), classified as a sex cord-stromal tumor, is a rare neoplasm. This is an instructive case report of JGCT accompanied by augmented interleukin (IL)-6 secretion. A 13-year-old girl with prolonged fever and delayed puberty was diagnosed with JGCT of the left ovary based on an imaging study and pathological investigation. Although it was not clear whether IL-6 was secreted from the tumor cells, her serum level of IL-6 was very high. After tumorectomy, the patient’s symptoms immediately disappeared, her IL-6 level decreased, and she entered puberty. Therefore, augmented IL-6 secretion production induced by tumors should be considered a potential cause of prolonged fever and/or delayed puberty

Direct measurement of radial strain in the inner-half layer of the left ventricular wall in hypertensive patients

SummaryBackgroundTwo-dimensional speckle tracking echocardiography (2D-STE) is a novel technology that directly measures regional left ventricular (LV) wall contraction. This study aimed to directly measure inner-layer thickening (radial strain) of the LV using 2D-STE, and to examine the relationship between radial strain and the degree of hypertrophy.MethodsThe study enrolled 63 untreated hypertensive patients with normal geometry (N group, n=32) or concentric hypertrophy (CH group, n=31), classified according to LV mass index (LVMI) and relative wall thickness (RWT). Thirty normotensive subjects (C group, n=30) served as controls. Radial strain (ɛ) in the inner half (ɛi) and all layers of the LV wall (ɛa) were calculated from the LV short-axis view by 2D-STE.ResultsLV ejection fraction did not differ significantly among the groups. However, ɛi and ɛa were significantly lower in the CH group compared with the C and N groups (p<0.01). A ratio of ɛi to ɛa was significantly lower in the CH group compared with the C and N groups (p<0.01). A multivariate regression model that included midwall fractional shortening, E/e′, LVMI, RWT, and LV ejection fraction showed that LVMI (p=0.002) and RWT (p=0.014) were independent predictors (R2=0.59) of ɛi.ConclusionRadial strain in the inner half layer of the LV wall decreases in parallel with the degrees of LV concentricity and hypertrophy in hypertensive patients. Radial strain in the inner half layer may identify subtle systolic dysfunction even in hypertensive patients with preserved LV chamber function

A Remote-operated System to Map Radiation Dose in the Fukushima Daiichi Primary Containment Vessel

This paper describes the development of a submersible system based on a remote-operated vehicle coupled with radiation detectors to map the interior of the reactors at the Fukushima Daiichi nuclear power station. It has the aim oflocating fuel debris. The AVEXIS submersible vehicle used in this study has been designed as a low-cost, potentially disposable, inspection platform that is the smallest of its class and is capable of being deployed through a 150 mm diameter access pipe. To map the gamma-ray environment, a cerium bromide scintillator detector with a small form factor has been incorporated into the AVEXIS to identify radioactive isotopes via gamma-ray spectroscopy. This provides the combined system with the potential to map gamma-ray spectra and particle locations throughout submerged, contaminated facilities, such as Units 1, 2 and 3 of the Fukushima Daiichi nuclear power plant. The hypothesis of this research is to determine the sensitivity of the combined system in a submerged environment that replicates the combination of gamma radiation and water submersion but at lower dose rates

On the design of a remotely-deployed detection system for reactor assessment at Fukushima Daiichi

The premise behind this research is the design of a system that will allow fuel debris characterisation at Fukushima Daiichi. The precise location of the debris is not known for example as to whether it remains within the reactor pressure vessel or it has leaked through into the base of the pedestal below, additionally the state of the fuel is also in question as to whether this has corroded from within its encasing or if it is intact. The most likely scenario is a combination of all four of these situations. The flooding of the reactor floors immediately following the Fukushima accident adds an extra element of complexity for the detection system requiring it to be submersible and to hold any detector system in water tight confinement. The research carried out has involved extensive modifications to a previously-designed low-cost small-scale AVEXIS submersible inspection vehicle and the incorporation of a variety of radiation detectors. The latter has been designed to allow for mapping and determination of the situation that is present within the primary containment vessels. The challenges addressed with the detection system arise from the high dose rates that have been recorded around the reactor pressure vessels which can be as high as 1000 Gy/hr. In such a harsh environment not only will the radiation detectors struggle to operate but the components that make up the remote-operated vehicle are also likely to suffer radiation damage after only a relatively short period of time. The research presented here evaluates the components currently incorporated into the AVEXIS system in terms of their radiation tolerability as well as presenting the combination of detectors to be used in the remote probe for the investigation of the fuel debris

Development of ROV system to explore fuel debris in the Fukushima Daiichi Nuclear Power Plant

Instruments and Methods were developed to explore fuel debris at the bottom of the Primary Containment Vessel in the Fukushima Daiichi Nuclear Power Plant. A Remotely Operated Vehicle was designed to explore fuel debris and to investigate the distribution and surface profile of fuel debris at the bottom of the primary containment vessel using a sonar and a compact radiation detector. Several tests were carried out using various facilities to determined the capabilities of the sonar and gamma-ray detector to determine the feasibility of the devic