Mouse Yolk Sac Hematopoiesis

The yolk sac is the first observed site of hematopoiesis during mouse ontogeny. Primitive erythroid cells are the most well-recognized cell lineages produced from this tissue. In addition to primitive erythroid cells, several types of hematopoietic cells are present, including multipotent hematopoietic progenitors. Yolk sac-derived blood cells constitute a transient wave of embryonic and fetal hematopoiesis. However, recent studies have demonstrated that some macrophage and B cell lineages derived from the early yolk sac may persist to adulthood. This review discusses the cellular basis of mouse yolk sac hematopoiesis and its contributions to embryonic and adult hematopoietic systems

<ORIGINAL REPORT>X-ray scanning analytical microscopic and scanning electron microscopic studies of an unusual case of dens invaginatus

A mass was extirpated from the region of the maxillary right third molar of a 20 year-old patient. It was proved to be an extreme and unerupted case of dens invaginatus. The clinical and histopathological features have been presented in a previous paper. Ameloblasts and odontoblasts were noted along the surface of enamel or dentin. In the present study, X-ray scanning analytical microscopy (XSAM), a newly developed technique, together with scanning electron microscopy (SEM) was applied for the study of this malformed tooth. SEM study showed a strange arrangement of well-formed enamel and dentin in normal structures. The distribution of calcium (Ca) and phosphorus (P) was clearly observed by the XSAM method. It revealed that the bulk of dentin was composed of two kinds of dentin quite different in mineral content while their SEM appearances were similar. The part of the dentin near the dentinoenamel junction had much higher Ca and P concentrations than the outer parts. In conclusion, the disagreement between the microscopic findings and the XSAM findings suggests the importance of applying various methods in studies to obtain a comprehensive understanding of such malformation. In addition, the present investigation also points out the complexity of the disturbance ranging within the term dens invaginatus

Injectable bioartificial myocardial tissue for large-scale intramural cell transfer and functional recovery of injured heart muscle

ObjectivesMost tissue-engineering approaches to restore injured heart muscle result in distortion of left ventricular geometry. In the present study we suggest seeding embryonic stem cells in a liquid matrix for myocardial restoration.MethodsUndifferentiated green fluorescent protein–labeled mouse embryonic stem cells (2 × 106) were seeded in Matrigel (B&D, Bedford, Mass). In a Lewis rat heterotopic heart transplant model an intramural left ventricular pouch was fashioned after ligation of the left anterior descending coronary artery. The liquid mixture (0.125 mL) was injected in the resulting infarcted area within the pouch and solidified within a few minutes after transplantation (37°C). Five recipient groups were formed: transplanted healthy hearts (group I), infarcted control hearts (group II), matrix recipients alone (group III), the study group that received matrix plus cells (group IV), and a group that received embryonic stem cells alone (group V). After echocardiography 2 weeks later, the hearts were harvested and stained for green fluorescent protein and cardiac muscle markers (connexin 43 and α-sarcomeric actin).ResultsThe graft formed a sustained structure within the injured area and prevented ventricular wall thinning. The inoculated cells remained viable and expressed connexin 43 and α-sarcomeric actin. Fractional shortening and regional contractility were better in animals that received bioartificial tissue grafts compared with control animals (infarcted, matrix only, and embryonic stem cells only: group I, 17.0% ± 3.5%; group II, 6.6% ± 2.1%; group III, 10.3% ± 2.2%; group IV, 14.5% ± 2.5%; and group V, 7.8% ± 1.8%).ConclusionsLiquid bioartificial tissue containing embryonic stem cells constitutes a powerful new approach to restoring injured heart muscle without distorting its geometry and structure

Electrochemical Na-Insertion/Extraction Properties of Phosphorus Electrodes in Ionic Liquid Electrolytes

The electrochemical Na-insertion/extraction properties of phosphorus as a Na-ion battery anode in ionic liquid electrolytes were investigated by using a thick film without any binder or conductive additive. The ionic liquid with more electrochemically-stable cation structure, 1-((2-methoxyethoxy)methyl)-1-methylpyrrolidinium bis(fluorosulfonyl)amide (Py1MEM-FSA), delivered a high reversible capacity of 310 mA h g−1 at the 100th cycle, whereas the phosphorus electrode in 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)amide (EMI-FSA) showed a low capacity of only 110 mA h g−1. It was revealed that disintegration of the electrode after cycling was effectively suppressed by applying Py1MEM-FSA instead of an organic electrolyte including propylene carbonate (PC), and that a surface layer induced by the decomposition of EMI-FSA hindered Na-insertion into the active material layer. The performance obtained in Py1MEM-FSA was very superior to that in PC. We applied for the first time a closed-system fire-resistance test to the ionic liquid electrolyte for quantitatively evaluating its non-flammability. The Py1MEM-FSA-based electrolyte exhibited an excellent fire resistance in comparison with the PC-based organic electrolyte, which can be an advantage for realizing a Na-ion battery with a high-energy density and a high safety

Influence of Diabetes Mellitus on Surgical Outcomes in Patients with Cervical Myelopathy: A Prospective, Multicenter Study

[Study Design] Multicenter, prospective study. [Purpose] To investigate the effects of diabetes mellitus (DM) on surgical outcomes in patients with cervical myelopathy. [Overview of Literature] To date, few studies have investigated the influence of postoperative blood glucose or glycated hemoglobin (HbA1c) levels on surgical outcomes. [Methods] The participants were patients who underwent surgery for the treatment of cervical spondylotic myelopathy and ossification of the posterior longitudinal ligament. The 61 cases were evaluated preoperatively and 1 year postoperatively using the Japanese Orthopaedic Association (JOA) scores and the JOA Cervical Myelopathy Evaluation Questionnaire (JOACMEQ). The study variables included fasting blood glucose and HbA1c levels measured preoperatively and at 1 week, 4 weeks, and 1 year postoperatively; the F-wave conduction velocity, latency, rate of occurrence, and M-wave latency in the ulnar and tibial nerves were measured preoperatively and at 1 year postoperatively. The patients were divided into a group without diabetes (N group, 42 patients) and a group with diabetes (DM group, 19 patients). We then assessed the associations between the surgical outcomes and each of the study variables. [Results] JOA scores significantly improved in both groups; however, no significant between-group differences were found. There was no significant improvement in the JOACMEQ scores, which assessed cervical function, upper and lower limb function, and bladder function in both groups. We then subdivided the DM group into those with a good control of HbA1c after 1 year (DMG group, 12 patients) and those with HbA1c deterioration after 1 year (DMB group, seven patients), prior to comparing the surgical outcomes. The JOACMEQ scores for upper and lower limb function significantly improved in the DMG group (p<0.01). Compared with the DMB group, there were no significant increases in upper or lower limb function scores in the DMG group. [Conclusions] Poor glycemic control might prevent postoperative functional recovery of the spinal cord

Synergistic effect of sulfonation followed by precipitation of amorphous calcium phosphate on the bone-bonding strength of carbon fiber reinforced polyetheretherketone

Sulfonation and applications of amorphous calcium phosphate are known to make polyetheretherketone (PEEK) bioactive. Sulfonation followed by precipitation of amorphous calcium phosphate (AN-treatment) may provide PEEK with further bone-bonding strength. Herein, we prepared a carbon-fiber-reinforced PEEK (CPEEK) with similar tensile strength to cortical bone and a CPEEK subjected to AN-treatment (CPEEK-AN). The effect of AN-treatment on the bone-bonding strength generated at the interface between the rabbit’s tibia and a base material was investigated using a detaching test at two time-points (4 and 8 weeks). At 4 weeks, the strength of CPEEK-AN was significantly higher than that of CPEEK due to the direct bonding between the interfaces. Between 4 and 8 weeks, the different bone forming processes showed that, with CPEEK-AN, bone consolidation was achieved, thus improving bone-bonding strength. In contrast, with CPEEK, a new bone was absorbed mainly on the interface, leading to poor strength. These observations were supported by an in vitro study, which showed that pre-osteoblast on CPEEK-AN caused earlier maturation and mineralization of the extracellular matrix than on CPEEK. Consequently, AN-treatment, comprising a combination of two efficient treatments, generated a synergetic effect on the bonding strength of CPEEK