Body Fat Assessment Method Using CT Images with Separation Mask Algorithm

In recent years, the number of obese population in Korea has been growing up along with the economic development, environmental factors, and the change in life style. Considering the growth of obese population and the adverse effect of obesity on health, it is getting more important to prevent and diagnose the obesity with the quantitative measurement of body fat that has become an important indicator for obesity. In this study, we proposed a procedure for the automated fat assessment from computed tomography (CT) data using image processing technique. The proposed method was applied to a single-CT image as well as CT-volume data, and results were correlated to those of dual-energy X-ray absorptiometry (DEXA) that is known as the reliable method for evaluating body fat. Using single-CT images, correlation coefficients between DEXA and the automated assessment and DEXA and the manual assessment were 0.038 and 0.058, respectively (P > 0.05). Hence, there was no significant correlation between three methods using the proposed method with single-CT images. On the other hand, in case of CT-volume data, the above correlation coefficients were increased to 0.826, 0.812, and 0.805, respectively (P < 0.01). Thus, DEXA and the proposed methods with CT-volume data showed highly significant correlation with each other. The results suggest that the proposed automated assessment using CT-volume data is a reliable method for the evaluation of body fat. It is expected that the clinical application of the proposed procedure will be helpful to reduce the time for the quantitative evaluation of patient’s body fat.     

Effects of strobe light stimulation on postnatal developing rat retina

The nature and intensity of visual stimuli have changed in recent years because of television and other dynamic light sources. Although light stimuli accompanied by contrast and strength changes are thought to have an influence on visual system development, little information is available on the effects of dynamic light stimuli such as a strobe light on visual system development. Thus, this study was designed to evaluate changes caused by dynamic light stimuli during retinal development. This study used 80 Sprague-Dawley rats. From eye opening (postnatal day 14), half of the rats were maintained on a daily 12-h light/dark cycle (control group) and the remaining animals were raised under a 12-h strobe light (2 Hz)/dark cycle (strobe light-reared group). Morphological analyses and electroretinogram (ERG) were performed at postnatal weeks 3, 4, 6, 8, and 10. Among retinal neurons, tyrosine hydroxylase-immunoreactive (TH-IR, dopaminergic amacrine cells) cells showed marked plastic changes, such as variations in numbers and soma sizes. In whole-mount preparations at 6, 8, and 10 weeks, type I TH-IR cells showed a decreased number and larger somata, while type II TH-IR cells showed an increased number in strobe-reared animals. Functional assessment by scotopic ERG showed that a-wave and b-wave amplitudes increased at 6 and 8 weeks in strobe-reared animals. These results show that exposure to a strobe light during development causes changes in TH-IR cell number and morphology, leading to a disturbance in normal visual functions.     

The Association between the Low Muscle Mass and Osteoporosis in Elderly Korean People

The purpose of this study was to predict osteoporosis risk as decreasing muscle mass and to declare the cut-off value of low muscle mass in an elderly Korean population. This study was based on data from the 2008-2010 Korea National Health and Nutritional Examination Surveys (KNHANES). The subjects included 1,308 men and 1,171 women over 65 yr. Bone mineral density (BMD) and appendicular skeletal muscle (ASM) were measured by dual energy X-ray absorptiometry (DXA), and appendicular skeletal muscle was adjusted by height as a marker of sarcopenia. After confirming the correlation between low muscle mass and BMD, the best cut-off value of muscle mass to estimate osteoporosis was suggested through the receiver operating characteristic (ROC) curve. For both men and women, BMD correlated positively with low muscle mass when ASM/Ht² was used as a marker for sarcopenia. The ROC curve showed that ASM/Ht² was the best marker for osteoporosis at a cut-off value of 6.85 kg/m² for men and 5.96 kg/m² for women. When these cut-off values were used to determine sarcopenia, the risk of osteoporosis increased 4.14 times in men and 1.88 times in women. In particular, men (OR 2.12) with sarcopenia were more greatly affected than women (OR 1.15), even after adjusting for osteoporosis risk factors. In elderly Korean people, sarcopenia is positively correlated with BMD and there is a strong correlation between sarcopenia and osteoporosis with risk of bone fracture.     

A Case of Congenital Adrenal Hyperplasia Mimicking Cushing's Syndrome

Congenital adrenal hyperplasia (CAH) is characterized by decreased adrenal hormone production due to enzymatic defects and subsequent rise of adrenocorticotrophic hormone that stimulates the adrenal cortex to become hyperplastic, and sometimes tumorous. As the pathophysiology is basically a defect in the biosynthesis of cortisol, one may not consider CAH in patients with hypercortisolism. We report a case of a 41-yr-old man with a 4 cm-sized left adrenal tumorous lesion mimicking Cushing''s syndrome who was diagnosed with CAH. He had central obesity and acanthosis nigricans involving the axillae together with elevated 24-hr urine cortisol level, supporting the diagnosis of Cushing''s syndrome. However, the 24-hr urine cortisol was suppressed by 95% with the low dose dexamethasone suppression test. CAH was suspected based on the history of precocious puberty, short stature and a profound suppression of cortisol production by dexamethasone. CAH was confirmed by a remarkably increased level of serum 17-hydroxyprogesterone level. Gene mutation analysis revealed a compound heterozygote mutation of CYP21A2 (I173N and R357W).     

Usage of nanoparticles with their potential toxicity assessment and regulatory guidelines

In recent times engineered nanoparticles have been receiving much attention from researchers due to their extensive use in a variety of chemical, biological, and industrial areas. Their physiochemical properties have led to a number of uses in commercial products. Considering their broad applications, with increasing human contact the risks of exposure are also increasing. In vivo toxicity experiments involving administering nanoparticles to living organisms have shown their adverse effects on organ development and reproduction. Nanoparticles can be considerably more toxic than the large-sized particles since they can move relatively freely compared to bulkier molecules. Henceforth, it is our duty to assess the harmful health consequences associated with human exposure to nanoparticles in order to improve safe production and use. We will review the current applications of nanoparticles, and issues related to their toxicity. We will focus on safety regulations, risk assessment and regulatory guidelines of nanoparticles. The validation and standardization of nanotoxicity tests will further promote safe applications of nanotechnology in our daily lives.