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The aim of the study was to estimate and to compare effective doses in the elbow region resulting from four different x‐ray imaging modalities. Absorbed organ doses were measured using 11 metal oxide field effect transistor (MOSFET) dosimeters that were placed in a custom‐made anthropomorphic elbow RANDO phantom. Examinations were performed using Shimadzu FH‐21 HR radiography device, Siemens Sensation Open 24‐slice MSCT‐device, NewTom 5G CBCT device, and Planmed Verity CBCT device, and the effective doses were calculated according to ICRP 103 recommendations. The effective dose for the conventional radiographic device was 1.5 µSv. The effective dose for the NewTom 5G CBCT ranged between 2.0 and 6.7 µSv, for the Planmed Verity CBCT device 2.6 µSv and for the Siemens Sensation MSCT device 37.4 µSv. Compared with conventional 2D radiography, this study demonstrated a 1.4–4.6 fold increase in effective dose for CBCT and 25‐fold dose for standard MSCT protocols. When compared with 3D CBCT protocols, the study showed a 6‐19 fold increase in effective dose using a standard MSCT protocol. CBCT devices offer a feasible low‐dose alternative for elbow 3D imaging when compared to MSCT. [ABSTRACT FROM AUTHOR]

Purpose: Radiation dose is a general concern in diagnostic imaging and a special concern for children who are at greater risk from radiation effects. This study evaluates effective doses (E) produced during 2D and volume imaging with a novel cone beam computed tomography (CBCT) based extremity imaging device. The device's compact size and protocol options offer image choices that enhance the potential for reduced dose and improved diagnostics when evaluating sports injuries. Methods: Hand‐wrist, foot‐ankle, and knee phantoms were developed for use with optically stimulated luminescent dosimeters (OSL). Dosimetry of transmission radiographs (2D) and CBCT volumes (3D) was assessed for Standard and lowered dose (Lite) exposure protocols. Effective dose was calculated for child and adult age groups. Image quality was assessed with contrast‐to‐noise ratio (CNR) and modulation transfer function (MTF). A figure of merit was calculated as the square of CNR divided by E. Results: Standard 2D doses ranged from 0.001–0.06 μSv for adults, 0.001–0.05 μSv for 15‐yr olds, 0.003–0.13 μSv for 10‐yr olds, and 0.005–0.20 for 5‐yr olds. Dose reductions with Lite protocols ranged from 26 to 51%. Standard CBCT doses ranged from 0.3–4.6 μSv for adults, 0.3–4.4 μSv for 15‐yr olds, 0.6–9.8 μSv for 10‐yr olds, and 1–22.6 μSv for 5‐yr olds. For both 2D and 3D a trend of increasing imaging dose with reduced age was present and was statistically significant for children below the age of 10 (P = 0.0009). Lite dose reductions averaged 47%. CNR was statistically reduced in Lite dose scans (P = 0.0384) but was not statistically different using FOM analysis (P = 0.3089). MTF was not significantly affected by the two dose protocols (P = 0.8104). Conclusion: CBCT effective doses calculated from anthropomorphic phantom exposures following manufacturer suggested protocols appear to be substantially less than previously reported doses for similar MDCT extremity examinations. In this study, effective dose from 2D radiographic imaging was approximately two orders of magnitude less than CBCT imaging. Doses were on the order of a few minutes to hours of ubiquitous per‐capita background dose for 2D imaging and a few hours to days for 3D imaging. Dose significantly increased for children younger than age 10. Lite protocols resulted in substantial dose reductions and can be recommended for children and those examinations where reduced CNR will not affect diagnosis. Flexibility of 2D and 3D imaging options with low‐dose protocols make this technology a promising option for radiographic evaluation of the extremities. Efficacy studies are needed to determine when MDCT, CBCT or Digital Radiography are best used for particular diagnostic tasks. [ABSTRACT FROM AUTHOR]

Objective To evaluate the type and prevalence of incidental findings from cone beam computed tomography ( CBCT) of the maxillofacial region. Findings are divided into those that require (i) intervention/referral, (ii) monitoring, and (iii) no further evaluation. Methods Three hundred consecutive CBCT scans conducted in the University of North Carolina School of Dentistry Oral and Maxillofacial Radiology Clinic from January 1 to August 31, 2008 were retrospectively reviewed. Findings were categorized into airway, soft tissue calcifications, bone, temporomandibular joint ( TMJ), endodontic, dental developmental, and pathological findings. Results A total of 272 scans revealed 881 incidental findings (3.2 findings/scan). The most prevalent was airway findings (35%) followed by soft tissue calcifications (20%), bone (17.5%), TMJ (15.4%), endodontic (11.3%), dental developmental (0.7%), and pathological (0.1%). 16.1% required intervention/referral, 15.6% required monitoring, and the remainder (68.3%) required neither. Conclusion This study underscores the need to thoroughly examine all CBCT volumes for clinically significant findings within and beyond the region of interest. [ABSTRACT FROM AUTHOR]

Myocardin (MYOCD) is a smooth and cardiac muscle-specific transcriptional coactivator that is required for the proper expression of contraction-related genes. Through its function to transactivate effector genes, MYOCD plays an essential role in mediating the switch between contractile and non-contractile phenotypes, particularly in smooth muscle cells (SMC). There are at least two known transcript variants of MYOCD that are expressed in SMC, differing only by the presence (+) or absence (Δ) of Exon 11. To date, no functional role has been assigned to the domain encoded by Exon 11, nor have any notable differences between the ability of each isoform to activate contraction-related genes been observed. In this study we compared sequences for Exon 11 among several mammalian species and identified a highly conserved, putative target sequence for glycogen synthase kinase 3 (GSK3) phosphorylation, suggesting a regulatory role for Exon 11 that can be modulated by alternative splicing. The function of Exon 11 was investigated by altering MYOCD splice selection in cultured porcine SMC with small interfering RNAs (siRNA) and specific chemical inhibitors, resulting in a relative increase in expression of ΔExon 11 variants in the endogenous pool of MYOCD mRNA. The relative increase in ΔExon 11 mRNAs correlated with a reduction of contractile phenotype in the porcine SMC as evidenced by morphological assessment and molecular analysis of effector genes. Together, these data suggest that MYOCD ΔExon 11 may participate in modulating SMC phenotype, potentially acting as a dominant-negative repressor of contraction-related genes. J. Cell. Physiol. 226: 2702-2711, 2011. © 2010 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

The availability of suitable human livers for transplantation falls short of the number of potential patients. In addition, the availability of primary human hepatocytes for cell-therapy and drug development applications is significantly limited; less than 700 livers per year are available for such studies. However, the majority of these organs cannot be utilized due to pathological infections (e.g., HepB, HepC, or HIV) or excessive levels of steatosis. Thus, the number of cells needed for cell therapy applications far exceeds the number of cells available from donated livers. The ability to implant progenitor cell populations that can form liver tissue in situ, or can be differentiated in vitro would be a major advance in current cell-based therapies. In addition, and importantly for this application, the ability to utilize a non-hepatic progenitor cell to mimic hepatocytes in vitro would enable the scale-up production of cells for bioartifical liver assist devices, cell-therapy and drug discovery applications. We demonstrate the feasibility of inducing adipose-derived stromal (ASC) cells to express several features of human hepatocytes such as glycogen storage and expression of liver specific genes. Importantly, we also show that undifferentiated ASCs and ASC-derived hepatic cells engraft robustly into the liver in a mouse model of toxic injury. These data indicate a significant potential for the use of undifferentiated ASCs and ASC-derived hepatic cells as novel and valuable products for cell therapy. J. Cell. Physiol. 225: 429–436, 2010. © 2010 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Adipose tissue serves as a source of adipokines and cytokines with both local and systemic actions in health and disease. In this study, we examine the hypothesis that multipotent human adipose-derived stem cells (ASCs), capable of differentiating along the adipocyte, chondrocyte, and osteoblast pathways, contribute to adipose tissue-derived cytokine secretion. Following exposure to basic fibroblast growth factor (bFGF) or epidermal growth factor (EGF), the ASCs significantly increase their secretion of hepatocyte growth factor (HGF), a cytokine implicated in hematopoiesis, vasculogenesis, and mammary epithelial duct formation. Ascorbic acid synergizes with these inductive factors, further increasing HGF levels. Following exposure to lipopolysaccharide, ASCs increase their secretion of both hematopoietic (granulocyte/monocyte, granulocyte, and macrophage colony stimulating factors, interleukin 7) and proinflammatory (interleukins 6, 8, and 11, tumor necrosis factor α) cytokines based on ELISA and RT-PCR. In co-cultures established with umbilical cord blood-derived CD34+ cells, the ASCs support long-term hematopoiesis in vitro. Furthermore, in short-term 12-day co-cultures, the ASC maintain and expand the numbers of both myeloid and lymphoid progenitors. These observations are consistent with the functionality of the secreted cytokines and confirm recent reports by other laboratories concerning the hematopoietic supportive capability of ASCs. We conclude that the ASCs display cytokine secretory properties similar to those reported for bone marrow-derived mesenchymal stem cells (MSCs). J. Cell. Physiol. 212:702–709, 2007. © 2007 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Cho J-J, Joseph B, Sappal BS, Giri RK, Wang R, Ludlow JW, Furth ME, Susick R, Gupta S. Analysis of the functional integrity of cryopreserved human liver cells including xenografting in immunodeficient mice to address suitability for clinical applications. Liver International 2004: 24: 361–370. © Blackwell Munksgaard 2004 The availability of well-characterized human liver cell populations that can be frozen and thawed will be critical for cell therapy. We addressed whether human hepatocytes can recover after cryopreservation and engraft in immunodeficient mice. We isolated cells from discarded human livers and studied the properties of cryopreserved cells. The viability of thawed cells was established with multiple in vitro assays, including analysis of liver gene expression, ureagenesis, cytochrome P450 activity, and growth factor-induced cell proliferation. The fate of transplanted cells was analysed in immunodeficient NOD-SCID mice. After thawing, the viability of human hepatocytes exceeded 60%. Cells attached to culture dishes, proliferated following growth factor stimulation and exhibited liver-specific functions. After transplantation in NOD-SCID mice, cells engrafted in the peritoneal cavity, a heterologous site, as well as the liver itself, retained hepatic function and proliferated in response to liver injury. Transplanted hepatocytes were integrated in the liver parenchyma. Occasionally, transplanted cells were integrated in bile ducts. Cryopreserved human liver cell showed the ability to retain functional integrity and to reconstitute both hepatic and biliary lineages in mice. These studies offer suitable paradigms aimed at characterizing liver cells prior to transplantation in people. [ABSTRACT FROM AUTHOR]

The purpose of this study was to determine if there was a significant difference in the diagnostic quality of the initial full-mouth series (FMS) exposed by first-year dental students after viewing a Computer Assisted Instruction (CAI) module on radiographic technique as compared to those who did not and to determine if students who used the CAI module expressed a preference to using it and would recommend its use prior to exposure. Fifty-nine first-year dental students were randomly selected and assigned to two groups (students who did not view a CAI CD and students who did) before exposing their initial FMS on a Dental X-ray Training and Teaching Replica (DXTTR). For each radiographic series, a radiology faculty member determined the total number of error points based on performance criteria. The Wilcoxon Rank Sum Test was used to determine significance between the two groups, p = .05. After exposing the FMS, students in the second group completed a questionnaire to assess their preference for using the CAI CD. The Sign Rank Test was used to determine preference, p = .05. No significant difference in error points were found to exist between the two groups. Dental students who reviewed the CAI preferred using it and would recommend it to others before exposing their FMS. [ABSTRACT FROM AUTHOR]

Tuned Aperture Computed Tomography or TACT® is a relatively new technique that transform correlated two-dimensional images into a three-dimensional display. Associating TACT with digital subtraction radiography (TACT-DSR) may enhance its use in the detection of diseases. This study aims to assess observer performance in the task of detecting simulated bone-gain in periodontal defects, comparing conventional and TACT DSR. Buccal, lingual and proximal pericrestal bony defects in a human and wax mixtures using standardized vertical bitewing projections, acquired with an intraoral digital receptor in a tomographic X-ray machine. One hundred and twenty pairs of baseline and follow-up images were obtained for each imaging modality. Post-acquisition processing including image-registration, density-correction and subtraction operation were applied to both transmission images and TACT-slices. Eight calibrated observers evaluated the presence or a absence of pericrestal bone-gain using a 5-point confidence scale. Details about the location of periodontal defects and the amount of bone-gain for each subtracted image were recorded and used in the statistical analysis. Observer performance and study design factors were analyzed by means of receiver operating characteristic (ROC) curve analysis and ANOVA. Mean values of areas under ROC curves for bone-gain detection performance were 0.82 for conventional DSR and 0.90 for TACT-DSR. TACT-DSR provided statistically superior detection performance of simulated periodontal bone-gain over conventional DSR for both-obscured defects (p=0.001) and for the smallest bone mass (p=0.024). The findings support TACT-DSR's potential to provide greater sensitivity and technique flexibility in detecting periodontal bone-gain than standard DSR. [ABSTRACT FROM AUTHOR]

Self-guided slide/tape (ST) and web page (WP) instruction in normal radiographic anatomy of periapical and panoramic images is compared using objective test performance and subjective preference of freshman dental students. A class of seventy-four students was divided into a group studying anatomy in periapical images using WP and a group studying similar ST material. In a modified cross-over design the groups switched presentation technologies to learn anatomy in panoramic images. Students completed self-administered on-line quizzes covering WP materials and conventional quizzes for ST material. Students also completed a voluntary survey. Mean quiz performance identifying matched anatomic features in PA (n = 26) and panoramic images (n = 35) was excellent (96.9%) and not different between image types (p = 0.12) or presentation technologies (p = 0.81). Students preferred WP for accessibility, ease of use, freedom of navigation, and image quality (p < .01). Student comfort level with the quiz formats of the two technologies was not different (p = 0.11). Students experienced a higher rate of mechanical and logistical problems with ST than with WP technology. While 71 percent of the students preferred WP technology, this preference appears to be related to ease of use and facilitation of flexible learning styles rather than improved didactic performance. [ABSTRACT FROM AUTHOR]

The retinoblastoma protein (Rb) acts as a critical cell-cycle regulator and loss of Rb function is associated with a variety of human cancer types. Here we report that Rb binds to members of the AP-1 family of transcription factors, including c-Jun, and stimulates c-Jun transcriptional activity from an AP-1 consensus sequence. The interaction involves the leucine zipper region of c-Jun and the B pocket of Rb as well as a C-terminal domain. We also present evidence that the complexes are found in terminally differentiating keratinocytes and cells entering the G1 phase of the cell cycle after release from serum starvation. The human papillomavirus type 16 E7 protein, which binds to both c-Jun and Rb, inhibits the ability of Rb to activate c-Jun. The results provide evidence of a role for Rb as a transcriptional activator in early G1 and as a potential modulator of c-Jun expression during keratinocyte differentiation. [ABSTRACT FROM AUTHOR]