Relationship between Vitamin D, Parathyroid Hormone, and Bone Mineral Density in Elderly Koreans

There is controversy regarding definition of vitamin D inadequacy. We analyzed threshold 25-hydroxyvitamin D (25[OH]D) below which intact parathyroid hormone (iPTH) increases, and examined age- and sex-specific changes of 25(OH)D and iPTH, and association of 25(OH)D and iPTH with bone mineral density (BMD) in elderly Koreans. Anthropometric parameters, serum 25(OH)D and iPTH, lumbar spine and femur BMD by dual-energy radiography absorptiometry (DXA) were measured in 441 men and 598 postmenopausal women. iPTH increased below serum 25(OH) of 36.7 ng/mL in men, but failed to reach plateau in women. Femur neck BMD above and below threshold differed when threshold 25(OH)D concentrations were set at 15-27.5 ng/mL in men, and 12.5-20 ng/mL in postmenopausal women. Vitamin D-inadequate individuals older than 75 yr had higher iPTH than those aged ≤ 65 yr. In winter, age-associated iPTH increase in women was steeper than in summer. In conclusion, vitamin D inadequacy threshold cannot be estimated based on iPTH alone, and but other factors concerning bone health should also be considered. Older people seemingly need higher 25(OH)D levels to offset age-associated hyperparathyroidism. Elderly vitamin D-inadequate women in the winter are most vulnerable to age-associated hyperparathyroidism

Visual Inspection of the Heavy-Duty Paint Systems Used in Steel Bridges for Assessing the Level of Fire Damage

After a fire on a steel bridge, a visual inspection is necessary to rapidly determine the need for an emergency response to ensure the structural safety of the bridge and decide whether to re-open the bridge to traffic. In this study, the visual inspection methods of assessing the coated surface were reviewed, as they are crucial for the rapid estimation of the steel temperature reached during the fire, which, in turn, is required for the safety assessment of steel bridges after a fire. An electric furnace heating test was conducted on the steel specimens coated with four types of heavy-duty paint systems for steel bridges, viz., urethane, siloxane, ceramic, and fluorocarbon. The heating temperatures and durations used in the test were 100, 150, 200, 250, 300, 400, 500, and 600 °C at 30 and 60 min. Based on the heating temperature and duration, the paint-film surface conditions (discoloration, blistering, cracking, and delamination) were visually inspected for a qualitative analysis, and factors such as color difference, gloss retention, and pull-off adhesion were quantitatively analyzed. The visual inspection methods used to estimate the temperature of the paint film were reviewed. In addition, considering the reduction in the tension strength of the steel material and the coating durability performance according to the fire temperature, the determinants of the traffic stop–reopening timeline and the repair and reuse of the painting system based on the visual field inspection after a fire were suggested

Shielding effect of radiation dose reduction fiber during the use of C-arm fluoroscopy: A phantom study

This study evaluated the shielding effect of a newly developed dose-reduction fiber (DRF) made from barium sulfate, in terms of radiation doses delivered to patients' radiosensitive organs and operator during C-arm fluoroscopy and its impact on the quality of images. A C-arm fluoroscopy unit was placed beside a whole-body phantom. Radiophotoluminescent glass dosimeters were attached to the back and front of the whole-body phantom at 20 cm intervals. Radiation doses were measured without DRF and with it applied to the back (position 1), front (position 2) or both sides (position 3) of the phantom. To investigate the impact of DRF on the quality of fluoroscopic images, step-wedge and modulation transfer function phantoms were used. The absorbed radiation doses to the back of the phantom significantly decreased by 25.3-88.8% after applying DRF to positions 1 and 3. The absorbed radiation doses to the front of the phantom significantly decreased by 55.3-93.6% after applying DRF to positions 2 and 3. The contrast resolution values for each adjacent step area fell in the range 0.0119-0.0209, 0.0128-0.0271, 0.0135-0.0339 and 0.0152-0.0339 without and with DRF applied to positions 1, 2 and 3, respectively. The investigated DRF effectively reduces absorbed radiation doses to patients and operators without decreasing the quality of C-arm fluoroscopic images. Therefore, routine clinical use of the DRF is recommended during the use of C -arm fluoroscopy.Y

Effect of metallic tools on scattered radiation dose during the use of C-arm fluoroscopy in orthopaedic surgery

This study investigated the effect of metallic tools on the scattered radiation dose delivered to surgeons' radiosensitive organs while simulating hip surgery using C-arm fluoroscopy. Two phantoms, a pelvis and a Rando phantom, were used to simulate a patient and a surgeon in this study. Photoluminescence dosimeters were inserted into the Rando phantom in the positions of the eye, thyroid and gonad. A drill was positioned above the hip of the pelvis phantom or beside the pelvis phantom of the same height. For each drill location, the scattered radiation dose was measured when the angle to the operator phantom was 45 degrees; this was repeated when the angle was 90 degrees. The scattered radiation doses to the eye, thyroid and gonad when the drill was placed beside the pelvis phantom with 90 degrees angulation to the operator phantom were significantly lower than the reference values and those when the drill was placed beside the pelvis phantom at a 45 degrees angulation to the operator phantom. The scattered radiation doses to the eye and thyroid when the drill was placed above the hip were significantly lower than the references values. Of the four different scenarios, the scattered radiation doses to the eye, thyroid and gonad were lowest when the drill was placed beside the pelvis phantom with 90 degrees angulation. This study showed that the scattered radiation doses to radiosensitive organs were affected by the location and angle of the metallic tools in relation to the operator. Therefore, orthopedic surgeons should consider the effect of metallic tools on the scattered radiation dose during intraoperative use of C-arm fluoroscopy.Y

Gene editing with ‘pencil’ rather than ‘scissors’ in human pluripotent stem cells

Abstract Owing to the advances in genome editing technologies, research on human pluripotent stem cells (hPSCs) have recently undergone breakthroughs that enable precise alteration of desired nucleotide bases in hPSCs for the creation of isogenic disease models or for autologous ex vivo cell therapy. As pathogenic variants largely consist of point mutations, precise substitution of mutated bases in hPSCs allows researchers study disease mechanisms with “disease-in-a-dish” and provide functionally repaired cells to patients for cell therapy. To this end, in addition to utilizing the conventional homologous directed repair system in the knock-in strategy based on endonuclease activity of Cas9 (i.e., ‘scissors’ like gene editing), diverse toolkits for editing the desirable bases (i.e., ‘pencils’ like gene editing) that avoid the accidental insertion and deletion (indel) mutations as well as large harmful deletions have been developed. In this review, we summarize the recent progress in genome editing methodologies and employment of hPSCs for future translational applications

Chronic TGF beta stimulation promotes the metastatic potential of lung cancer cells by Snail protein stabilization through integrin beta 3-Akt-GSK3 beta signaling

Chronic exposure to TGFβ, a frequent occurrence for tumor cells in the tumor microenvironment, confers more aggressive phenotypes on cancer cells by promoting their invasion and migration while at the same time increasing their resistance to the growth-inhibitory effect of TGFβ. In this study, a transdifferentiated (TD) A549 cell model, established by chronically exposing A549 cells to TGFβ, showed highly invasive phenotypes in conjunction with attenuation of Smad-dependent signaling. We show that Snail protein, the mRNA expression of which strongly correlates with a poor prognosis in lung cancer patients, was highly stable in TD cells after TGFβ stimulation. The increased protein stability of Snail in TD cells correlated with elevated inhibitory phosphorylation of GSK3β, resulting from the high Akt activity. Notably, integrin β3, whose expression was markedly increased upon sustained exposure to TGFβ, was responsible for the high Akt activity as well as the increased Snail protein stability in TD cells. Consistently, clinical database analysis on lung cancer patients revealed a negative correlation between overall survival and integrin β3 mRNA levels. Therefore, we suggest that the integrin β3-Akt-GSK3β signaling axis plays an important role in non-canonical TGFβ signaling, determining the invasive properties of tumor cells chronically exposed to TGFβ.

Performances of a protector against scattered radiation during intraoperative use of a C-arm fluoroscope

The scattered radiation protector for mobile x-ray systems, Creative Valuable Protector-2, has been recently developed. However, there have been no studies investigating the effects of this device. We aim to investigate the effects of the scattered radiation protector on the equivalent doses from scattered radiation delivered to radiosensitive organs while simulating spine surgery using a C-arm fluoroscope. Chest and rando phantoms were used to simulate a patient and a surgeon in this study. The equivalent dose from scattered radiation to radiosensitive organs was measured in four different situations according to the use of the scattered radiation protector and the C-arm configuration. To compare the quality of the images with and without the scattered radiation protector, an acryl step phantom with five steps was used, and the contrast resolution of each step was calculated. The equivalent dose from the scattered radiation to the surgeon's eye, thyroid, and gonad decreased significantly by using the scattered radiation protector for both the Posteroanterior (PA) (p < 0.001) and Anteroposterior (AP) (p < 0.001) C-arm configurations. The installation of the scattered radiation protector also reduced the direct radiation dose to the chest phantom. A scattered map showed that scattered radiation doses decreased by approximately 50% for the PA configuration and 75% for the AP configuration by using the scattered radiation protector. Before and after installation of the scattered radiation protector, the contrast resolution of each adjacent step area was 0.025-0.404 and 0.216-0.421. The scattered radiation protector was effective in reducing not only the equivalent dose from scattered radiation to the surgeon's radiosensitive organs, but also the direct radiation dose to the patient. This was all achieved without decreasing the quality of the C-arm fluoroscopic images.N