Identifying key gait features associated with the radiological grade of knee osteoarthritis.

PURPOSE: Knee osteoarthritis (KOA) is characterized by pain and decreased gait function. This study assessed key features that can be used as mechanical biomarkers for KOA severity and progression. The identified features were validated statistically and were further examined by developing a classification model based on a machine-learning algorithm. METHODS: The study included 227 volunteers with various grades of KOA. The severity of KOA was graded using the Kellgren-Lawrence (KL) system. A total of 165 features were extracted from the gait data. The key features were selected using neighborhood component analysis. The selected features were validated using the t-test. Then, the features were examined by building a classification model using a random forest algorithm. RESULTS: Twenty features were identified that could discriminate the grade of KOA, including nine features extracted from the knee joint, seven from the hip, two from the ankle and two from the spatiotemporal gait parameters. The t-test showed that some features differed significantly between health and sever group, while some were significantly different among the severe group, and others were significantly different for all KL grades. The areas under the receiver operating characteristic curves for classification were 0.974, 0.992, 0.845, 0.894, and 0.905 for KL grades 0 through 4, respectively. CONCLUSION: Key gait features reflecting the grade of KOA were identified. The results of the statistical analysis and machine-learning algorithm show that the features can discriminate the severity of disease according to the KL grade.

The duration of hyaluronidase and optimal timing of hyaluronic acid (HA) filler reinjection after hyaluronidase injection.

BACKGROUND: Hyaluronidase injection is a commonly performed treatment for overcorrection or misplacement of hyaluronic acid (HA) filler. Many patients often wants the HA filler reinjection after the use of hyaluronidase, though the optimal timing of reinjection of HA filler still remains unknown. OBJECTIVES: To provide the optimal time interval between hyaluronidase injections and HA filler reinjections. METHODS: 6 Sprague-Dawley rats were injected with single monophasic HA filler. 1 week after injection, the injected sites were treated with hyaluronidase. Then, HA fillers were reinjected sequentially with differing time intervals from 30 minutes to 14 days. 1 hour after the reinjection of the last HA filler, all injection sites were excised for histologic evaluation. RESULTS: 3 hours after reinjection of HA filler, the appearance of filler material became evident again, retaining its shape and volume. 6 hours after reinjection, the filler materials restored almost its original volume and there were no significant differences from the positive control. CONCLUSIONS: Our data suggest that the hyaluronidase loses its effect in dermis and subcutaneous tissue within 3-6 hours after the injection and successful engraftment of reinjected HA filler can be accomplished 6 hours after the injection.

Increased protein oxidation and decreased expression of nuclear factor E2-related factor 2 protein in skin tissue of patients with diabetes.

BACKGROUND: Reactive oxygen species (ROS) contribute to the cell dysfunction and tissue damage that result from glucolipotoxicity in diabetes. ROS formation in cells causes oxidative stress, thereby activating oxidative damage-inducing genes. Nuclear factor erythroid 2-related factor 2 (Nrf2) has been shown to play an essential role in the vital defence mechanisms that help cells cope with oxidative stress. AIM: To compare Nrf2 protein expression in nondiabetic skin tissue with that in diabetic skin tissue. METHODS: Nrf2 expression was evaluated by Western blotting, reverse transcription (RT)-PCR, and immunohistochemical staining in diabetic and nondiabetic skin tissues. Dinitrophenylhydrazone derivatives of protein carbonyls in the oxidized proteins were measured by oxyblotting analysis. Cytoplasmic and nuclear Nrf2 protein expression was determined to identify the activity and level of Nrf2. RESULTS: Protein oxidation, a marker of oxidative stress, was found to be increased in diabetic skin tissue. In subcellular fraction analysis, Nrf2 protein was detected in the nuclei and cytoplasm of nondiabetic skin tissues, and the Nrf2 protein band was identified from among the multiple bands detected, using small interfering RNA-mediated Nrf2 gene silencing. Compared with nondiabetic tissue, diabetic skin tissue showed simultaneous downregulation of Nrf2 at both the mRNA and protein levels. Nuclear condensation, loss of nuclei, and vacuolization were seen in some parts of the specimen by haematoxylin and eosin staining of diabetic skin tissue. Immunohistochemical staining of Nrf2 confirmed the RT-PCR and Western blotting results. CONCLUSIONS: Collectively, our data show that expression of Nrf2 is clearly downregulated in diabetic skin tissue, and suggest that Nrf2 may be necessary for protection against glucose-induced oxidative stress.

Indole-3-carbinol enhances ultraviolet B-induced apoptosis by sensitizing human melanoma cells.

Indole-3-carbinol (I3C) has been found to act against several types of cancer, while ultraviolet B (UVB) is known to induce the apoptosis of human melanoma cells. Here, we investigated whether I3C can sensitize G361 human melanoma cells to UVB-induced apoptosis. We examined the effects of combined I3C and UVB (I3C/UVB) at various dosages. I3C (200 microM)/UVB (50 mJ/cm(2)) synergistically reduced melanoma cell viability, whereas I3C (200 microM) or UVB (50 mJ/cm(2)), separately, had little effect on cell viability. DNA fragmentation assays indicated that I3C/UVB induced apoptosis. Further results show that I3C/UVB activates caspase-8, -3, and Bid and causes the cleavage of poly(ADP-ribose) polymerase. Moreover, I3C decreased the expression of the anti-apoptotic protein, Bcl-2, whereas UVB increased the translocation of Bax to mitochondria. Thus, an increased Bax/Bcl-2 ratio by I3C/UVB may result in melanoma apoptosis. In conclusion, our study demonstrated that I3C sensitizes human melanoma cells by down-regulating Bcl-2.

Examining the effect of length/width ratio on the hydro-dynamic behaviour in a DAF system using CFD and ADV techniques.

Dissolved air flotation (DAF) is a solid-liquid separation system that uses fine bubbles rising from the bottom to remove particles in water. In this study, we investigated the effect of L/W(L; length, W; width) on the hydrodynamic behavior in a DAF system using CFD (computational fluid dynamics) and ADV (acoustic Doppler velocimetry) technique. The factual full-scale DAF system, L/W ratio of 1:1, was selected and various UW ratio conditions (2:1, 3:1,4:1 and 5:1) were simulated with CFD. For modelling, 2-phase (gas-liquid) flow equations for the conservation of mass, momentum and turbulence quantities were solved using a Eulerian-Eulerian approach based on the assumption that a very small particle is applied in the DAF system. Also, for verification of CFD simulation results, we measured the actual velocity at some points in the full-scale DAF system with the ADV technique. Both the simulation and the measurement results were in good accordance with each other. We concluded that the L/W ratio and outlet geometry play an important role for flow pattern and fine bubble distribution in the flotation zone. In the ratio of 1:1, the dead zone is less than those in other cases. On the other hand, in the ratio of 5:1, the fine bubbles were more evenly distributed.

Application of the flotation process to thicken the sludge from a DAF plant.

Dissolved air flotation (DAF) was evaluated for thickening of the sludges from a water treatment plant which uses DAF. Solid flux theory for gravity thickening was applied to the solid flux of DAF sludge. The higher the polymer dosage, at fixed solid concentration, the greater the rising velocity becomes. When applied with solid flux equations, a similar relationship to that of gravity thickening has been found. However, the values were much higher than in gravity thickening, because both the inflow solid concentration and the floating velocity were higher than for settled sludge. With this result, the proper dosage of polymer could be derived from the relationship between total solid flux and withdrawal velocity of DAF sludge.

Regulation of osteoclast differentiation by the redox-dependent modulation of nuclear import of transcription factors.

This study sought to characterize the reduced glutathione (GSH)/oxidized GSSG ratio during osteoclast differentiation and determine whether changes in the intracellular redox status regulate its differentiation through a RANKL-dependent signaling pathway. A progressive decrease of the GSH/GSSG ratio was observed during osteoclast differentiation, and the phenomenon was dependent on a decrease in total glutathione via downregulation of expression of the gamma-glutamylcysteinyl synthetase modifier gene. Glutathione depletion by L-buthionine-(S,R)-sulfoximine (BSO) was found to inhibit osteoclastogenesis by blocking nuclear import of NF-kappaB and AP-1 in RANKL-propagated signaling and bone pit formation by increasing BSO concentrations in mature osteoclasts. Furthermore, intraperitoneal injection of BSO in mice resulted in an increase in bone density and a decrease of the number of osteoclasts in bone. Conversely, glutathione repletion with either N-acetylcysteine or GSH enhanced osteoclastogenesis. These findings indicate that redox status decreases during osteoclast differentiation and that this modification directly regulates RANKL-induced osteoclastogenesis.

Dissemination of transferable CTX-M-type extended-spectrum beta-lactamase-producing Escherichia coli in Korea.

AIMS: Among 365 Escherichia coli isolated in 2003, 31 cefotaxime-resistant isolates were obtained from clinical specimens taken from adults hospitalized in Busan, Korea. Six extended-spectrum beta-lactamase (ESBL)-producing isolates were investigated further to determine the mechanism of resistance. METHODS AND RESULTS: These isolates were analysed by antibiotic susceptibility testing, pI determination, plasmid profiles, transconjugation test, PCR-restriction fragment length polymorphism (RFLP), enterobacterial repetitive consensus (ERIC)-PCR and DNA sequencing. All six of these isolates were found to contain the CTX-M-type ESBL genes. Five clinical isolates and their transconjugants produced CTX-M-3. One clinical isolate (K17391) and its transconjugant (trcK17391) produced CTX-M-15. Five clinical isolates also produced another TEM-1. One clinical isolate (K12776) also contained another TEM-52. CTX-M-3 ESBL gene was responsible for the resistance to piperacillin, cephalothin, cefotaxime, cefepime and aztreonam. CTX-M-15 or TEM-52 was especially responsible for the resistance to ceftazidime. CONCLUSIONS: These results appear to represent the in vivo evolution of CTX-M-type beta-lactamase genes (bla(CTX-M-3) --> bla(CTX-M-15)) under the selective pressure of antimicrobial therapy (especially ceftazidime). PCR-RFLP is a reliable method to discriminate CTX-M-15 gene from CTX-M-3 gene. ERIC-PCR analysis revealed that dissemination of CTX-M-3 was not due to a clonal outbreak of a resistant strain but to the intra-species spread of resistance to piperacillin, cephalothin, cefotaxime, cefepime and aztreonam in Korea. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first report of the occurrence of CTX-M-1 cluster ESBLs in Korea. A more comprehensive survey of these ESBL types from Korea is urgently needed because of the in vivo evolution of CTX-M-15 from CTX-M-3. The emergence of these CTX-M-type ESBLs suggests that diagnostic laboratories should screen for ESBLs with ceftazidime as well as cefotaxime; they should still perform clavulanate synergy tests on resistant isolates.

Investigation of a nosocomial outbreak of Acinetobacter baumannii producing PER-1 extended-spectrum beta-lactamase in an intensive care unit.

We investigated an outbreak of Acinetobacter baumannii in an adult intensive care unit of Kosin University Gospel Hospital in Busan, Republic of Korea. The outbreak involved 10 cases of infection by A. baumannii producing PER-1 extended-spectrum beta-lactamase over a seven-month period, and was caused by a single pulsed-field gel electrophoresis clone. The epidemic isolates were characterized by slight synergy between clavulanic acid and cefepime. Isoelectric focusing of crude bacterial extracts detected two nitrocefin-positive bands with pI values of 8.0 and 5.3. Polymerase chain reaction amplification and characterization of the amplicons by restriction analysis and direct sequencing indicated that the epidemic isolates carried a bla(PER-1) determinant. The epidemic isolates were characterized by a multidrug-resistant phenotype that remained unchanged over the outbreak, including penicillins, beta-lactam/beta-lactamase inhibitor, extended-spectrum cephalosporins and monobactams. Isolation of infected patients and appropriate carbapenem therapy were successful in ending the outbreak. Our report indicates that the bla(PER-1) resistance determinant may become an emerging therapeutic problem.

Isolation of human epidermal stem cells by adherence and the reconstruction of skin equivalents.

The isolation of human epidermal stem cells is critical for their clinical applications. In the present study, we isolated three populations of epidermal keratinocytes according to their ability to adhere to collagen type IV: i.e., rapidly adhering (RA), slowly adhering (SA), and non-adhering (NA) cells. The aim of this study was to characterize RA cells and to investigate the possibility of using these cells for epidermis reconstruction. To identify RA cells, flow cytometric analysis was performed using anti-alpha(6) integrin and anti-CD71 antibodies. RA cells express high levels of alpha(6) integrin and low levels of CD71, which are considered as markers of an epidermal stem cell nature. Furthermore, electron microscopy showed that RA cells are small and have a high nuclear to cytoplasmic ratio, whereas SA and NA cells have well-developed cellular organelles and abundant tonofilaments. Western blot analysis showed that RA cells are slow cycling and express p63, a putative epidermal stem cell marker, whereas SA and NA cells express c-Myc, which is known to regulate stem cell fate. To compare epidermal regenerative abilities, skin equivalents (SEs) were made using RA, SA, and NA cells. The epidermis constructed from RA cells was well formed compared to those formed from SA or NA cells. In addition, only SEs with RA cells expressed alpha(6) integrin and beta(1) integrin at the basal layer. These results indicate that RA cells represent epidermal stem cells and are predominately comprised of stem cells. Therefore, the isolation of RA cells using a simple technique offers a potential route to their clinical application, because they are easily isolated and provide a high yield of epidermal stem cells.

Investigation of extended-spectrum beta-lactamases produced by clinical isolates of Klebsiella pneumoniae and Escherichia coli in Korea.

AIMS: Isolates obtained from various regions in Korea in 2002 were identified and their susceptibility to extended-spectrum cephalosporins, monobactams and/or cephamycins was studied along with any production of extended-spectrum beta-lactamases (ESBLs). METHODS AND RESULTS: Bacteria identified by the conventional techniques and Vitek GNI card were Klebsiella pneumoniae and Escherichia coli. Using disk diffusion and double-disk synergy tests, we found that 39.2% of strains produced ESBLs. About 52% of isolates transferred resistance to ceftazidime by conjugation. Banding patterns of PCR amplification with the designed primers showed that 837- and 259-bp fragments specific to bla(TEM) genes were amplified in 63.3% of strains. 929- and 231-bp fragments (bla(SHV)), 847- and 520-bp fragments (bla(CMY)), 597- and 858-bp fragments (bla(CTX-M)) were amplified in 61.5, 17.3 and 7.7% of strains respectively. About 51.9% of strains contained more than two types of beta-lactamase genes. Especially, one strain contained bla(TEM), bla(CMY) and bla(CTX-M) genes. SIGNIFICANCE: Resistance mechanisms to beta-lactams, comprising mostly ESBL production, lead to the resistance against even recently developed beta-lactams in enterobacteria, which is now a serious threat to antibiotic therapy. The high prevalence of bla(CMY) genes and multidrug-resistant genes may also make therapeutic failure and lack of eradiation of these strains by extended-spectrum cephalosporins or cephamycins.

Study on size distribution of total aerosol and water-soluble ions during an Asian dust storm event at Jeju Island, Korea.

Soil dust particles transported from loess regions of the Asian continent, called Asian dust, highly influences the air quality of north-eastern Asia and the northern Pacific Ocean. In order to investigate the effects of these dust storms on the chemical composition of atmospheric aerosol particles with different size, measurements of size distributions of total aerosol and major ion species were carried out on Jeju Island, Korea during April 2001. Juju Island was chosen for the study because the levels of emissions of anthropogenic air pollutants are very low. A 5-stage cascade impactor was used to sample size-fractionated aerosol particles. Samples were analyzed for major water-soluble ions using Dionex DX-120 ion chromatograph. The average mass concentration of total aerosol was found to be 24.4 and 108.3 microg m(-3) for non-Asian dust and Asian dust periods, respectively. The total aerosol size distribution, measured during the non-Asian dust period, was bimodal, whereas the coarse particles dominated the size distribution of total aerosol during the Asian dust period. It was found that SO4(2-), NH4+ and K+ were mainly distributed in fine particles, while Cl-, NO3-, Na+, Mg2+ and Ca2+ were in coarse particles. Although SO4(2-) was mainly distributed in fine particles, during the Asian dust period, the concentrations in coarse particles were significantly increased. This indicates heterogeneous oxidation of SO2 on wet surfaces of basic soil dust particles. The NH4+ was found to exist as (NH4)2SO4 in fine particles, with a molar ratio of NH4+ to SO4(2-) of 2.37 and 1.52 for non-Asian dust and Asian dust periods, respectively. Taking into account the proximity of the sampling site to the sea, and the observed chloride depletion, coarse mode nitrate, during the non-Asian dust period, is assumed to originate from the reaction of nitric acid with sodium chloride on the surfaces of sea-salt particles although the chloride depletion was not shown to be large enough to prove this assumption. During the Asian dust period, however, chloride depletion was much smaller, indicating coarse nitrate particles were mainly produced by the reaction of nitric acid with surfaces of basic soil particles. Most chloride and sodium components were shown to originate from sea-salt particles. Asian dust aerosols, arriving at Jeju Island, contained considerable amounts of sea-salt particles as they passed over the Yellow Sea. Ca2+ was shown to be the most abundant species in Asian dust particles.

A case study of dissolved air flotation for seasonal high turbidity water in Korea.

A DAF (Dissolved-Air-Flotation) process has been designed considering raw water quality characteristics in Korea. Although direct filtration is usually operated, DAF is operated when freshwater algae blooms occur or raw water turbidity becomes high. Pre-sedimentation is operated in case when the raw water turbidity is very high due to rainstorms. A main feature of this plant is that the operation mode can be changed (controlled) based on the characteristics of the raw water to optimize the effluent quality and the operation costs. Treatment capacity (surface loading rate) and efficiency of DAF was found to be better than the conventional sedimentation process. Moreover, low-density particles (algae and alum flocs) are easily separated while the removal of them by sedimentation is more difficult. One of the main concerns for DAF operation is a high raw water turbidity. DAF is not adequate for raw water, which is more turbid than 100 NTU. In order to avoid this problem, pre-sedimentation basins are installed in the DAF plant to decrease the turbidity of the DAF inflow. For simulation of the actual operation, bench and full-scale tests were performed for highly turbid water conditions. Consequently, it is suggested that pre-sedimentation with optimum coagulation prior to DAF is the appropriate treatment scheme.

Dietary supplementation of (+)-catechin protects against UVB-induced skin damage by modulating antioxidant enzyme activities.

PURPOSE: The aim of this study was to investigate the effects of dietary supplementation with (+)-catechin on cutaneous antioxidant enzymes and the skin damage caused by UVB irradiation. METHODS: BALB/c mice were divided into three groups. Each group was fed a regular diet (RD) or a 2% catechin-supplemented diet for either 2 weeks (2CSD) or 4 weeks (4CSD) ad libitum prior to UVB irradiation. Skin was removed for the antioxidant enzyme assay, hematoxylin and eosin staining, and the TEM analysis before and at various time points after UVB (200 mJ/cm2) irradiation. RESULTS: Before UVB irradiation, the superoxide dismutase (SOD) and catalase (CAT) activities of the 2CSD and the 4CSD groups were found to be lower than those of the RD group, whereas the glutathione peroxidase (GPx) activity of the 4CSD group was higher than those of the RD and the 2CSD groups (P<0.05). The SOD and CAT activities of the RD group decreased after UVB irradiation, while those of the 2CSD and the 4CSD groups increased immediately after irradiation and then decreased (P<0.05). Immediately after UVB irradiation, the GPx activities of the 4CSD and the 2CSD groups increased, but that of the RD group decreased. The GPx activity of all three groups showed a tendency to return to pre-UVB irradiation levels with time. Light microscopic findings of the RD group showed epidermal thinning and apoptotic cells at 24 h after UVB irradiation and mostly necrotic cells at 48 h, whereas only moderate thickening of the epidermis was observed in the 2CSD group at 48 h after irradiation. An electron microscopic examination produced similar findings. At 48 h after irradiation, nearly all epidermal cells seemed to be damaged in the RD group as compared to the 2CSD group. CONCLUSION: These results demonstrate that dietary supplementation with (+)-catechin could protect epidermal cells against UVB-induced damage by modulating antioxidant enzyme activities.

Zantedeschia mosaic virus causing leaf mosaic symptom in calla lily is a new potyvirus.

Anovel virus, Zantedeschia mosaic virus (ZaMV-KR), causing mosaic and malformation symptoms was isolated from calla lily ( Zantedeschia spp.) in Korea and its biological and molecular properties were characterized. The virus was distinct from Dasheen mosaic virus, an Araceae-infecting potyvirus, by serological and sequence analyses. Multiple alignments of the CP amino acid sequence between the virus and other potyviruses showed 51.8 to 62.1% identity. Phylogenetic analyses of the CP revealed that the virus could be clustered with Plum pox virus and Turnip mosaic virus. Sequence comparison of the CP gene between the virus and three other ZaMV isolates from Taiwan showed over 93.9% identity, and most of amino acids changes occurred in the N-terminal region. Sequence comparison of 3' NTR revealed homology levels of 27.0 to 47.9% between the virus and other potyviruses. Our results support ZaMV as a distinct species of the genus Potyvirus.

Zucchini green mottle mosaic virus is a new tobamovirus; comparison of its coat protein gene with that of kyuri green mottle mosaic virus.

A novel virus we call zucchini green mottle mosaic virus (ZGMMV) was isolated from zucchini squash and its properties were determined. The size and shape of its virions, and other properties suggest that the virus is a tobamovirus. The coat protein (CP) genes of ZGMMV and kyuri green mottle mosaic virus (KGMMV), which also infects zucchini squash plants, were cloned and their nucleotides sequences were determined. The CP genes of ZGMMV and KGMMV are composed of 161 amino acid residues, and they share 77.6% amino acid identity. Western blot analysis showed that the two viruses are serologically related but not identical. Comparison of the sequences with those of sixteen other tobamoviruses revealed that the two viruses had much higher identity to cucumber green mottle mosaic virus (CGMMV), another tobamovirus infectious to cucurbit plants, than other tobamoviruses. The nucleotide and amino acid sequences of ZGMMV were from 29.5 to 78.4% and from 29.3 to 77.6% identical, respectively, to those of other tobamoviruses. The predicted virion assembly origins of the two tobamoviruses were located in the CP region of the genomic RNAs, and the predicted secondary structures were more similar to that of CGMMV than those of other tobamoviruses. The seventeen tobamo-viruses could be classified into three main subgroups based on the phylogenetic tree analysis on the CP gene, and ZGMMV and KGMMV formed a third subgroup together with CGMMV and sunn-hemp mosaic virus (SHMV). These results show that ZGMMV is a previously unknown member of the Tobamovirus genus.

Outbreak of rat mite dermatitis in medical students.

BACKGROUND: The tropical rat mite, Ornithonyssus bacoti (0. bacoti), is an ectoparasite on many rodents, but when the rodent is not available, humans may become the victim of the mite's bite. The bite induces a nonspecific dermatitis; therefore, it is not easy to diagnose rat mite dermatitis unless the parasites are found. MATERIALS AND METHODS: Ten cases of rat mite dermatitis were found in medical students who had studied in the same room of the library. Their nonspecific dermatitis consisted of small papules, and parasites were found in the skin or in the environment. The mites were collected and identified as O. bacoti, female. Histopathologic studies showed moderate perivascular lymphohistiocytic infiltrations intermingled with some eosinophils. The presence of rodents in or around the room was confirmed by the students, but there had been no preceding rodent eradication. Although the rats were not captured in the library, insecticides were sprayed, and no further problem with either mites or dermatitis developed during the follow-up period. CONCLUSIONS: Rat mite dermatitis can occur in clusters that involve a common source of exposure to the rat mite epidemiologically. Prompt identification of rat mites and the eradication of mites and rodents from the environment can prevent further spreading of the disease.