Dealing with pediatric fracture patients requires a funded knowledge of complications and remodeling capability of the youth skeleton to find the accurate therapy decision and to avoid unnecessary ...invasive procedures. Due to the different mechanical environment, fractures in children occur at specific fracture-vulnerable areas. One of those is the growth plate, which on one hand gives rise to the unique ability of correcting angular deformities by specifically increasing the growth rate in definite regions, and on the other hand leads to complications like growth arrest or angular deformity. The pediatric diaphysis presents the exclusive greenstick fracture, only seen in the growing skeleton, which occurs because of the different composition of the pediatric bone. To understand these very specific features of the youth skeleton, the molecular and cellular basis should be taken into consideration. Therefore, this review will present the common characteristics of skeletal development and fracture healing. An insight into the mechanotransduction as part of the remodeling and self-correcting ability of pediatric bone is given to span the bridge between clinical treatment options and scientific background. PUBLICATION ABSTRACT
AIM:To ascertain whether the Prague circumferential(C) length and maximal(M) length criteria for grading the extent of Barrett’s esophagus can be applied prior to its widespread application in South ...Korea.METHODS:Two hundred and thirteen consecutive cases with endoscopic columnar-lined esophagus(CLE) were included and classified according to the Prague C and M criteria.RESULTS:Of 213 cases with CLE, the distribution of maximum CLE lengths was: 0.5-0.9 cm in 99 cases(46.5%); 1.0-1.4 cm in 63 cases(29.6%); 1.5-1.9 cm in 15 cases(7.0%); 2.0-2.4 cm in 14 cases(6.6%); 2.5-2.9 cm in 1 case(0.5%); and 7.0 cm in 1 case(0.5%). Twenty cases(9.4%) had columnar islands alone. Two hundred and eight cases(97.7%) lacked the circumferential CLE component(C0Mx). Columnar islands were found in 70 cases(32.9%), of which 20 cases(9.4%) had columnar islands alone.CONCLUSION:In regions where most CLE patients display short or ultrashort tongue-like appearance, more detailed descriptions of CLE’s in < 1.0 cm lengths and columnar islands, as well as avoidance of repeating the prefix "C0" need to be considered in parallel with the widespread application of the Prague system in South Korea.
Forklift truck is a very convenient transportation vehicle and widely used in industries. However, a lot of overturn accidents occur during operation because of poor understanding on the stability of ...forklift trucks. The stability of a forklift is defined by the minimum slope of the ramp where a forklift truck overturns. According to the KS BISO 22915-2 code, the stability is determined from the four kinds of stability tests. The equations for the stability of a forklift truck were proposed already in several published literatures and the equations can be used conveniently to estimate the stability and examine the effects of design parameters in forklift trucks. However, because the detail derivation procedure was omitted, it is very difficult to examine the accuracy of the proposed equations and to modify the equations for other types of forklift trucks. In this paper the stability equations were derived again with detail derivations for the four kinds of stability tests. And the effects of acceleration or centrifugal forces were also additionally included in the equations and minor corrections were also made.
4T1 mouse mammary tumor cells can be implanted sub-cutaneously in nu/nu mice to form palpable tumors in 15 to 20 days. This xenograft tumor model system is valuable for the pre-clinical in vivo ...evaluation of putative antitumor compounds. The 4T1 cell line has been engineered to constitutively express the firefly luciferase gene (luc2). When mice carrying 4T1-luc2 tumors are injected with Luciferin the tumors emit a visual light signal that can be monitored using a sensitive optical imaging system like the IVIS Spectrum. The photon flux from the tumor is proportional to the number of light emitting cells and the signal can be measured to monitor tumor growth and development. IVIS is calibrated to enable absolute quantitation of the bioluminescent signal and longitudinal studies can be performed over many months and over several orders of signal magnitude without compromising the quantitative result. Tumor growth can be monitored for several days by bioluminescence before the tumor size becomes palpable or measurable by traditional physical means. This rapid monitoring can provide insight into early events in tumor development or lead to shorter experimental procedures. Tumor cell death and necrosis due to hypoxia or drug treatment is indicated early by a reduction in the bioluminescent signal. This cell death might not be accompanied by a reduction in tumor size as measured by physical means. The ability to see early events in tumor necrosis has significant impact on the selection and development of therapeutic agents. Quantitative imaging of tumor growth using IVIS provides precise quantitation and accelerates the experimental process to generate results.
Integrins are cell-substrate adhesion proteins that initiate intracellular signaling and may serve as mechanosensors in bone. MLO-Y4 cells were stably transfected with a dominant negative form of the ...beta sub(1) integrin subunit ( beta sub(1)DN) containing the transmembrane domain and cytoplasmic tail of beta sub(1) integrin. Cells expressing beta sub(1)DN had reduced vinculin localization to focal contacts but no change in intracellular actin organization. When exposed to oscillatory fluid flow, beta sub(1)DN cells exhibited a significant reduction in the upregulation of cyclooxygenase-2 gene expression and prostaglandin E sub(2) release. Similarly, the ratio of receptor activator of NF- Kappa B ligand mRNA to osteoprotegerin mRNA decreased significantly after exposure to fluid flow in control cells but not in beta sub(1)DN cells. Interfering with integrin signaling did not affect mechanically induced intracellular calcium mobilization. These data suggest that integrins may initiate the cellular response of osteocytes to dynamic fluid flow and may serve as mechanosensitive molecules in bone.
Integrins are cell-substrate adhesion proteins that initiate intracellular signaling and may serve as mechanosensors in bone. MLO-Y4 cells were stably transfected with a dominant negative form of the ...beta^sub 1^ integrin subunit (beta^sub 1^DN) containing the transmembrane domain and cytoplasmic tail of beta^sub 1^ integrin. Cells expressing beta^sub 1^DN had reduced vinculin localization to focal contacts but no change in intracellular actin organization. When exposed to oscillatory fluid flow, beta^sub 1^DN cells exhibited a significant reduction in the upregulation of cyclooxygenase-2 gene expression and prostaglandin E^sub 2^ release. Similarly, the ratio of receptor activator of NF-kappaB ligand mRNA to osteoprotegerin mRNA decreased significantly after exposure to fluid flow in control cells but not in beta^sub 1^DN cells. Interfering with integrin signaling did not affect mechanically induced intracellular calcium mobilization. These data suggest that integrins may initiate the cellular response of osteocytes to dynamic fluid flow and may serve as mechanosensitive molecules in bone. PUBLICATION ABSTRACT
Little is known about the formation of niches, local micro-environments required for stem cell maintenance. Here we develop an
in vivo
assay for adult hematopoietic stem cell (HSC) niche formation
1
...-
2
. With this assay, we identified a population of progenitor cells with surface markers CD45
-
Tie2
-
α
V
+
CD105
+
Thy1.1
-
(CD105
+
Thy1
-
) that when sorted from 15.5 dpc fetal bones (fb) and transplanted under the adult mouse kidney capsule could recruit host-derived blood vessels, produce donor-derived ectopic bones through a cartilage intermediate, and generate a marrow cavity populated by host-derived long term reconstituting HSC (LT-HSC). In contrast, CD45
-
Tie2
-
α
V
+
CD105
+
Thy1
+
(CD105
+
Thy1
+
) fb progenitors form bone that does not contain a marrow cavity. Suppressing expression of factors involved in endochondral ossification, such as osterix and VEGF, inhibited niche generation
22
-
24
. CD105
+
Thy1
-
progenitor populations derived from regions of the fetal mandible or calvaria that do not undergo endochondral ossification formed only bone without marrow in our assay
27
. Collectively, our data implicates endochondral ossification, bone formation that proceeds through a cartilage intermediate, as a requirement for adult HSC niche formation.
Introduction: Identification and understanding of the cells and processes that can generate, sustain and influence the HSC niche and hematopoiesis are critical for the development of a more ...comprehensive knowledge of normal hematopoiesis, stem cell homing, trafficking, differentiation and hematopoietic pathology. Growth and renewal in many tissues are initiated by stem cells, supported by the microenvironment (niche) in which they reside. While recent work has begun to describe functional interactions between stem cells and their niches, little is known about the formation of stem cell niches.
Methods & Results: We established a functional, in vivo assay (via implantation of cells under the renal capsule) to isolate the determinants of hematopoietic stem cell (HSC) niche formation and activity. Using this novel assay, we show that a population of progenitor cells (CD45−Tie2-aV+CD105+Thy1.1−; CD105+Thy1−) sorted from 15.5 dpc fetal limbs and transplanted under the adult mouse renal capsule recruit host-derived vasculatures in a VEGF dependent manner, produce donor-derived ectopic bones through endochondral ossification, and generate a marrow cavity populated by host-derived long term reconstituting HSC (LT-HSC). In contrast, CD45−Tie2-aV+CD105+Thy1a+ (CD105+Thy1+) progenitors form bone that does not contain a marrow cavity. While analyzing these and other sorted populations, we did not observe any instances where niche was present without bone, suggesting that skeletal progenitors are necessary for initiating an HSC niche but osteoblasts alone cannot initiate and support niche activity. Suppression of factors important for HSC maintenance, such as steel factor (SLF), in progenitor populations prior to transplant did not alter their ability to initiate and support an HSC niche. On the other hand, suppression of factors involved in endochondral ossification, such as osterix and VEGF, inhibited niche generation. Furthermore, CD105+Thy1− progenitor populations derived from regions of the fetal mandible or calvaria that do not undergo endochondral ossification form only bone without marrow in our assay.
Conclusions: In addition to identifying the limb-derived skeletal progenitor capable of endochondral ossification involved and the basic mechanisms of HSC niche initiation, our study provides a functional framework by which future studies on HSC-niche interactions at the cellular level can be carried out.
AIM: To evaluate the effects of butein on inflammatory cytokines, matrix metalloproteinase-9(MMP-9), andcolitis in interleukin(IL)-10-/- mice.METHODS: To synchronize colitis, 8- to 10-wk-old IL-10-/- ...mice were fed pellet-chow containing piroxicam for 2 wk. Subsequently, phosphate-buffered saline or butein(1 mg/kg per day, ip) was injected for 4 wk. Histologic scores, inflammatory cytokines, MMP-9 and phosphorylated signal transducer and activator of transcription 3(p STAT3) expressions were analyzed in IL-10-/- mice and in Colo 205 cells.RESULTS: Butein reduced the colonic inflammatory score by > 50%. Expression levels of IL-6, IL-1β, interferon(IFN)-γ and MMP-9 were decreased in the colons of mice exposed to butein, whereas other inflammatory cytokines(IL-17 A, IL-21 and IL-22) were unchanged. Immunohistochemical staining for p STAT3 and MMP-9 was significantly decreased in the buteintreated groups compared with the controls. Butein inhibited IL-6-induced activation of STAT3 in Colo 205 cells.CONCLUSION: Butein ameliorated colitis in IL-10-/-mice by regulating IL-6/STAT3 and MMP-9 activation.
Cerebellum plays an important role in integration of sensory perception and motor coordination. Although it constitutes only 10 % of total brain volume, cerebellum contains nearly 50 % of all neurons ...in the brain. To investigate the roles of cells in cerebellum during physiological and pathological processes in a model system in vitro, we established and characterized a cerebellar cell line (CRBL) isolated from mice lacking expression of a gene involved in cell cycle. Unlike the culture of cerebellar cells from wild type animals that undergoes senescence, the CRBL cells immortally survived in vitro. They were resistant to G418 treatments due to the expression of a neo‐cassette inserted in the middle of the target gene open reading frame. Their growth was greatly influenced by the different levels of serum in the media. Karyotype analysis of the cell line revealed hypotetraploidy. The changes in the numbers of chromosomes varied. The CRBL cells were morphologically heterogeneous displaying the cells of variable sizes and shapes. By flow cytometry and Western blotting analysis we found CRBL cells express a neuronal cell marker protein beta‐III tubulin, a glial cell marker protein glial fibrillary acidic protein, and cellular prion protein. This newly established cell line will be a valuable tool to understand cerebellar functions and neuropathological mechanisms in cerebellum.
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