Environmental exposure of heavy metal (lead and cadmium) and hearing loss: data from the Korea National Health and Nutrition Examination Survey (KNHANES 2010-2013).

BACKGROUND: Lead and cadmium have been identified as risk factors for hearing loss in animal studies, but large-scale studies targeting the general human population are rare. This study was conducted to investigate the link between heavy metal concentrations in blood and hearing impairment, using a national population-based survey. METHODS: The study participants comprised 6409 Koreans aged 20 or older, who were included in the Fifth and Sixth Korea National Health and Nutrition Examination Surveys (KNHANES 2010-2013). Hearing impairment was categorized into two types, low- and high-frequency hearing impairment, using pure tone audiometry. Low-frequency hearing impairment was defined as having a binaural average of hearing thresholds for 0.5, 1, and 2 kHz exceeding 25 dB, and high-frequency hearing impairment was defined as having a binaural average of hearing thresholds for 3, 4, and 6 kHz exceeding 25 dB. The blood levels of heavy metals (lead and cadmium) were classified into quartiles. Cross-sectional association between hearing impairment and the level of heavy metals (lead and cadmium) was examined in both sexes. Multivariate logistic regression was used to obtain adjusted odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: Among men, the prevalence of low- and high- frequency hearing impairment was 13.9% and 46.7%, respectively, which was higher than the prevalence among women (11.8% and 27.0%, respectively). Regarding lead, the adjusted OR of high-frequency hearing impairment for the highest blood level group versus the lowest group was significant in both men (OR = 1.629, 95% CI = 1.161-2.287) and women (OR = 1.502, 95% CI = 1.027-2.196), after adjusting for age, body mass index, education, smoking, alcohol consumption, exercise, diagnosis of diabetes mellitus, hypertension, and noise exposure (occupational, loud, firearm noises). No links were found between blood lead levels and low-frequency hearing impairment, or between blood cadmium levels and low- or high-frequency hearing impairment in either sex. CONCLUSIONS: The present study findings suggest that even exposure to low-level lead is a risk factor for high-frequency hearing loss. A prospective epidemiologic study should be conducted to identify the causal relationship between human health and exposure to heavy metals, and efforts to reduce heavy metal exposure in the general population should continue.

Environmental Tobacco Smoke Exposure at Home and High-Sensitivity C-Reactive Protein Levels in Three-to-Five-Year-Old Children.

Exposure to harmful environmental factors is particularly detrimental to younger children. We investigated the relationship between environmental tobacco smoke (ETS) exposure in pre-schoolers at home and the level of high-sensitivity C-reactive protein (hs-CRP), a predictive factor for cardiovascular disease. This study was conducted in 2014 and was based on the data of preschool children from the Korean Environmental Health Survey in Children and Adolescents (2012 to 2014), a nationally representative sample. Of 577 children, aged three to five years, 482 were eventually selected for the analysis after excluding those with missing variables, or whose hs-CRP level exceeded the reference value. The proportion of pre-school children exposed to ETS at home was 14.8%. The odd ratios (OR)s of hs-CRP > 1mg/L were 4.90 (95% Confidence Interval (CI) = 1.04-23.17) and 11.66 (95% CI = 1.90-71.65) in the groups exposed to ETS 3-4 times and ≥5 times daily, respectively, compared to the non-exposed group. The risk of elevated levels of hs-CRP showed an increasing trend proportionally to the increase in ETS exposure frequency (p for trend = 0.03). Anti-smoking educational programs for parents and guardians may be helpful to reduce ETS exposure at home.

Evaluation of the dermatologic life quality among cleanroom workers in a secondary battery factory.

BACKGROUND: Cleanroom air is extremely dry, as it is maintained within 1 % of relative humidity. Few studies have assessed the dermatologic life quality of workers in ultralow-humidity environments. Therefore, we aimed to evaluate the dermatologic life quality of cleanroom workers using the Skindex-29, compared to those of non-cleanroom workers. METHODS: Study participants were 501 cleanroom workers and 157 non-cleanroom workers from a secondary battery factory, who underwent an employee health examination at a single university hospital from September 2014 to September 2015. Results of the self-administered Skindex-29, and McMonnies questionnaire were analyzed. Other information and disease history were also collected during physician's medical examination. Descriptive and multivariate logistic regression analysis were performed. RESULTS: The Skindex-29 score was significantly higher in cleanroom workers than in non-cleanroom workers for all domains, Symptom (16.0 ± 15.9 vs. 6.3 ± 10.2, p < 0.001), Emotion (11.3 ± 17.4 vs. 2.5 ± 7.4, p < 0.001), Function (5.2 ± 11.1 vs. 1.6 ± 4.0, p < 0.001), and Overall (10.8 ± 13.4 vs. 3.5 ± 6.2, p < 0.001). The Skindex-29 score of cleanroom workers was similar to that of patients with skin diseases such as psoriasis, other dermatitis, corns, alopecia etc. Among the cleanroom workers, 37 workers had one or more skin diseases. Among the risk factors, 'working at cleanroom', 'possessing skin disease' and 'McMonnies score' had significant strong correlations with Skindex-29 score, meanwhile age, sex, smoking, drinking and exercise had weak correlations with it. 'Working at cleanroom' and 'possessing skin disease' had highest odds ratios with overall 14.0 (C.I.: 5.9-33.1) and 13.4 (C.I.: 4.5-29.2), and the lowest odds ratios with function domain 3.5(C.I.: 1.7-7.1) and 4.5(C.I.: 2.1-9.5), respectively. The McMonnies score had the highest odds ratio with overall, 6.9(C.I.: 4.5-10.8) and lowest odd ratio with emotion domain 4.2 (C.I.: 2.7-6.4). CONCLUSIONS: Dermatologic life quality among cleanroom workers in the secondary battery factory is shown to be lower than that among non-cleanroom workers in this study. The study suggests that the Skindex-29 may provide helpful information on the dermatologic life quality of cleanroom workers. Therefore, regarding evaluation of dermatologic life quality using Skindex-29, preventive care is necessary for cleanroom workers in ultralow humidity environment.

Representative levels of blood lead, mercury, and urinary cadmium in youth: Korean Environmental Health Survey in Children and Adolescents (KorEHS-C), 2012-2014.

BACKGROUND: This study examined levels of blood lead and mercury, and urinary cadmium, and associated sociodemographic factors in 3-18 year-old Korean children and adolescents. MATERIALS AND METHODS: We used the nationally representative Korean Environmental Health Survey in Children and Adolescents data for 2012-2014 and identified 2388 children and adolescents aged 3-18 years. The median and 95th percentile exposure biomarker levels with 95% confidence intervals (CIs) were calculated. Multivariate regression analyses were performed on log transformed exposure biomarker levels adjusted for age, sex, area, household income, and father's education level. The median exposure biomarker levels were compared with data from Germany, the US, and Canada, as well as the levels of Korean children measured at different times. RESULTS: The median levels of blood lead and mercury, as well as urinary cadmium were 1.23µg/dL, 1.80µg/L, and 0.40µg/L (95% CIs, 1.21-1.25, 1.77-1.83, and 0.39-0.41, respectively). The blood lead levels were significantly higher in boys and younger children (p<0.0001) and children with less educated fathers (p=0.004) after adjusting for covariates. Urinary cadmium level increased with age (p<0.0001). The median levels of blood mercury and urinary cadmium were much higher in Korean children and adolescents than those in their peers in Germany, the US, and Canada. Blood lead levels tended to decrease with increasing age and divergence between the sexes, particularly in the early teen years. Median levels of blood lead and urinary cadmium decreased since 2010. CONCLUSION: Sociodemographic factors, including age, sex, and father's education level were associated with environmental exposure to heavy metals in Korean children and adolescents. These biomonitoring data are valuable for ongoing surveillance of environmental exposure in this vulnerable population.

Tobacco smoking-response genes in blood and buccal cells.

Tobacco smoking is a well-known cause of various diseases, however, its toxic mechanisms for diseases are not completely understood, yet. Therefore, we performed biological monitoring to find tobacco smoking-responsive mechanisms including oxidative stress in Korean men (N=36). Whole genome microarray analyses were performed with peripheral blood from smokers and age-matched nonsmokers. We also performed qRT-PCR to confirm the microarray results and compared the gene expression of blood to those of buccal cells. To assess the effects of tobacco smoking on oxidative stress, we analyzed urinary levels of malondialdehyde (MDA), a lipid peroxidation marker, and performed PCR-based arrays on reactive oxygen species (ROS)-related genes. As results, 34 genes were differently expressed in blood between smokers and nonsmokers (ps<0.01 and >1.5-fold change). Particularly, the genes involved in immune responsive pathways, e.g., the Fcγ-receptor mediated phagocytosis and the leukocyte transendothelial migration pathways, were differentially expressed between smokers and nonsmokers. Among the above genes, the ACTG1, involved in the maintenance of actin cytoskeleton, cell migration and cancer metastasis, was highly expressed by smoking in both blood and buccal cells. Concerning oxidative stress, smokers showed high levels of urinary MDA and down-regulation of expressions of antioxidant related genes including TPO, MPO, GPX2, PTGR1, and NUDT1 as compared to nonsmokers (ps<0.05). In conclusion, these results suggest that systemically altered immune response and oxidative stress can be tobacco-responsive mechanisms for the related diseases. Based on consistent results in blood and buccal cells, expression of the ACTG1 can be a tobacco smoking-responsive biomarker.

Stimuli-responsive siRNA carriers for efficient gene silencing in tumors via systemic delivery.

Development of efficient carriers for small interfering RNA (siRNA) delivery and validation tools for assessing in vivo RNA interference (RNAi) efficiency is crucial to advance RNAi-based therapeutics to the clinic. Here, acid-degradable ketalized linear polyethylenimine (KL-PEI) designed for efficient, stimuli-responsive, and biocompatible siRNA delivery was used to complex with GFP-silencing siRNA (GFP siRNA) for in vivo RNAi. The in vivo gene silencing efficiency of GFP siRNA/KL-PEI polyplexes was evaluated at mRNA, protein, and histological levels using a mouse bearing a GFP-expressing tumor. Intravenously injected GFP siRNA/KL-PEI polyplexes significantly reduced GFP expression in tumors and whole blood of mice, depending on the dosage of GFP siRNA and the time course. Average GFP mRNA levels in the tumors of siRNA/KL-PEI polyplex-injected mice were also reduced. The described siRNA carriers and RNAi validation methodologies in this study may provide insightful clues for the development of RNAi-based therapeutics and preclinical trials.

Enhancement of periprosthetic bone quality with topical hydroxyapatite-bisphosphonate composite.

BACKGROUND: Implant loosening is associated with inflammatory bone loss induced by ultra-high molecular weight polyethylene wear debris. We hypothesized that a hydroxyapatite-bisphosphonate composite improves periprosthetic bone quality and osseous integration of an intramedullary implant even in the presence of ultra-high molecular weight polyethylene particles in an experimental rat femur model. METHODS: A preliminary in vitro study determined the optimal concentration of zoledronate (50 microM) that would maximally decrease osteoclasts without harming osteoblasts. Hydroxyapatite-coated intramedullary nails were implanted bilaterally in the femora of sixteen rats (the control group), and hydroxyapatite-zoledronate-coated nails were implanted bilaterally in the femora of sixteen rats (the experimental group). Ultra-high molecular weight polyethylene particles were introduced into the femoral canal before implantation. Eight rats from each group were killed at six weeks, and the remaining rats were killed at six months. Periprosthetic bone mass was analyzed by dual x-ray absorptiometry and microcomputed tomography. Osseous integration was examined by biomechanical testing of pullout strength. RESULTS: The mean bone area (and standard deviation) in the periprosthetic bone region was significantly greater (p < 0.0001) in the hydroxyapatite-zoledronate group (2.388 +/- 0.960 mm2) than in the control group (0.933 +/- 0.571 mm2). This difference was larger in the six-week group than in the six-month group (p = 0.03). The average peak pullout force for the treated femora (241.0 +/- 95.1 N) was significantly greater (p < 0.0001) than that for the controls (55.6 +/- 49.0 N). This difference was similar in the six-week and six-month groups. The energy required for nail pullout was significantly greater (p < 0.0001) for the treated femora (521.6 +/- 293.8 N-mm) than for the controls (142.2 +/- 152.1 N-mm). This difference in energy to pullout was similar in the six-week and six-month groups. Regression analysis demonstrated a high correlation between periprosthetic bone mass and peak pullout force for both the six-week (r = 0.766, p = 0.0005) and six-month (r = 0.838, p < 0.0001) groups. CONCLUSIONS: Surface modification of implants with hydroxyapatite-zoledronate improves periprosthetic bone quality and osseous integration. CLINICAL RELEVANCE: Hydroxyapatite-based site-specific delivery of bisphosphonates may be one way of reducing ultra-high molecular weight polyethylene wear particle-induced periprosthetic osteolysis and implant loosening.

Targeting of cell survival genes using small interfering RNAs (siRNAs) enhances radiosensitivity of Grade II chondrosarcoma cells.

The main treatment for chondrosarcoma is surgical resection with a wide margin. However, there are certain chondrosarcomas, such as those found in the pelvis and the spine, which cannot be resected adequately with surgery alone. Unfortunately, most chondrosarcomas are resistant to radiation and chemotherapy. Radiation and chemotherapy are thought to kill chondrosarcoma cells by inducing apoptosis, or programmed cell death. In this article, we hypothesize that antiapoptotic gene silencing enhances radiosensitivity in chondrosarcoma cells by facilitating apoptotic pathways. We knocked down antiapoptotic genes in chondrosarcoma cells using small interfering RNAs (siRNAs). Two well-established Grade II human chondrosarcoma cell lines were pretreated with siRNAs that specifically target mRNAs for Bcl-2, Bcl-xL, or XIAP. The cells were then treated with radiation. Cell death was assessed by flow cytometry. Cell survival and proliferation were measured by clonogenic survival assays. Chondrosarcoma cells exhibited radioresistance and increased the expression of Bcl-2, Bcl-xL, and XIAP in response to radiation. When one of the Bcl-2, Bcl-xL, or XIAP genes was silenced with the corresponding siRNA, radiosensitivity increased up to 9.2-fold (p < 0.05). When two out of the three antiapoptotic mRNAs were knocked down simultaneously, there was an 11.3-fold increase in cell death after radiation (p < 0.05). Our findings support a novel therapeutic concept that gene silencing may be used as a molecular adjuvant therapy for radioresistant sarcomas.

Mechanical loading differentially regulates membrane-bound and soluble RANKL availability in MC3T3-E1 cells.

To understand the biochemical response of RANKL in response to mechanical loading, MC3T3-E1 cells were biequiaxially stretched. A murine RANKL cDNA with double epitopes, pEF6 HA-RANKL-V5His, was transfected into MC3T3-E1 cells, which were then stretched. Endogenous RANKL protein expression increased in response to mechanical loading. Membrane-bound RANKL (HA-RANKL-V5His) increased in cell lysates while soluble RANKL (RANKL-V5His) decreased in the conditioned media after mechanical loading. This may have resulted from the decreased activity of TACE after mechanical loading. Increased membrane-bound RANKL may be one of the mechanisms through which osteoblasts adapt to mechanical loading by regulating osteoclastogenic activity in a region-specific manner.

Stromal cell-derived factor 1 (SDF-1, CXCL12) is increased in subacromial bursitis and downregulated by steroid and nonsteroidal anti-inflammatory agents.

Several studies have demonstrated that inflammation in the subacromial bursa is an important component in the pathogenesis of impingement syndrome. We have demonstrated in a previous study that many inflammatory cytokines, including stromal cell-derived factor 1 (SDF-1, CXCL12), are increased in the subacromial bursa [Blaine et al. 2005. J Shoulder Elbow Surg 14(Suppl 1):84S-89S]. SDF-1 is a potent chemotactic and angiogenic factor that stimulates recruitment of inflammatory cells. In the current study, we proposed that the resident cells in subacromial bursal tissue produce SDF-1, which can play a role in the inflammatory reponse of bursal tissue, and that this chemokine can be regulated by steroid (dexamethasone) and nonsteroidal anti-inflammatory medications (NSAIDs). Twenty-two subacromial bursa tissues (18 bursitis and 4 normal bursa) were obtained intraoperatively from patients during shoulder surgery and analyzed using the cDNA Array technique in accordance with an IRB approved protocol. cDNA array results were confirmed with real-time reverse transcription-polymerase chain reaction (RT-PCR). Bursal cells (from 4 normal bursa, 3 bursitis) and two normal bone marrow with whole tissue explants were cultured for one passage. Cell culture supernatants were collected and SDF-1 protein was detected with enzyme-linked immunosorbent assay (ELISA). Cultured bursal cells were treated with a COX-2 inhibitor and dexamethasone, and cells was harvested at 1-day and 4-day intervals. SDF-1 expression was evaluated by real-time RT-PCR and ELISA. cDNA Array analysis demonstrated that the gene expression of SDF-1 was increased in patients with subacromial bursitis compared to controls (p < 0.05). Real-time RT-PCR also revealed that the mRNA expression of SDF-1 in bursitis tissue is increased 10-fold over control tissue. While the normal bursal cells produced negligible amounts of SDF-1 protein, cultured cells derived from bursitis lesion released as much SDF-1 protein (235 pg/100,000 cells) as normal bone marrow stromal cells (283 pg/100,000 cells) as measured by ELISA. The addition of a COX-2 inhibitor and dexamethasone to bursitis cell lines led to decreased SDF-1 expression levels compared to untreated bursitis cell lines. These studies demonstrate that there is a significant elevation of SDF-1 expression in the subacromial bursa of patients with rotator cuff disease. Furthermore, this chemokine can be downregulated by COX-2 inhibitors and steroids. These results provide biologic evidence for the use of steroid and NSAIDs in the treatment of subacromial bursitis. In the future, targeted inhibition of molecules such as SDF-1 in the subacromial bursa may present a therapeutic strategy that may avoid the side effects of these other (steroid and NSAID) medications.

[Correlates of self-rated fatigue in Korean employees].

OBJECTIVE: To elucidate the correlates of self-rated fatigue in Korean employees. METHODS: The data for 10,176 (men, 7984; women, 2192; mean age, 34.2; SD: 8.8) employees recruited from a nation-wide sample were examined. A structured questionnaire was used to measure the participants' fatigue, sociodemographics (sex, age, education, and marital status), job-related characteristics (work duration, grade at work, work hours, shiftwork, employment type, and magnitude of workplace), and health-related habits (smoking, drinking, coffee intake, and exercise). Two types of measurement for fatigue were used to evaluate the magnitude of fatigue: self-rated question and a standardized measurement tool (Multidimensional Fatigue Scale: MFS). RESULTS: According to the self-rated fatigue, 32% of employees reported that they felt fatigue for the past two weeks, and 9.6% of males and 8.7% of females had experienced excessive fatigue (6 months or more). Hierarchical multiple regression analysis showed that fatigue measured by MFS was more common in women, younger, college or more graduated, single, and employees who do not regularly exercise. Fatigue was also associated with long work hours, and the size of the workplace (< 1000 employees). CONCLUSIONS: These results suggest that fatigue has been considered as a common complaint, and that it is affected by job-related factors like work hours and the workplace size as well as sociodemographics or health-related behaviors. Further research is needed to clarify the effects of fatigue on adverse health,outcomes, work performance, work disability, sick absence and medical utilization, and to examine the relationship of job characteristics (e.g.: work demand, decision latitude) to fatigue.

GSTM1 [corrected] deletion modifies the levels of polycyclic aromatic hydrocarbon-DNA adducts in human sperm.

DNA adducts measured in tissues are promising markers for identifying damage in organs that could be a target for carcinogens. Polymorphisms in genes involved in polycyclic aromatic hydrocarbons (PAHs) metabolism have been shown to modify the levels of PAH-DNA adducts in target tissues. In order to study the role of metabolic gene polymorphisms on DNA-adduct formation in sperm, we determined the GSTM1 genotype in a group of men in whom PAH-DNA adducts in sperm had been previously measured by immunofluorescence. The mean level of adducts in sperm was significantly higher in subjects carrying the homozygous deletion variant of GSTM1 than in subjects with a functional GSTM1 (mean fluorescence staining intensity: 1.62+/-0.62 versus 1.33+/-0.55; p=0.02). With respect to environmental factors, subjects who reported occupational exposure to PAHs and who carried the GSTM1 deletion had a significant increase in PAH-DNA adducts in sperm in comparison with subjects who were not exposed and had a functional GSTM1 (mean staining intensity: 1.83+/-0.67 versus 1.30+/-0.53; p=0.05), although among GSTM1-null subjects there was no significant difference with or without occupational exposure. This study presents for the first time the effect of a common polymorphism in a gene that metabolizes PAHs on DNA-adduct levels in sperm.

mu-Calpain regulates receptor activator of NF-kappaB ligand (RANKL)-supported osteoclastogenesis via NF-kappaB activation in RAW 264.7 cells.

To clarify the role of calpain in the receptor activator of NF-kappaB ligand (RANKL)-supported osteoclastogenesis, RANKL-induced calpain activation was examined by using murine RAW 264.7 cells and bone marrow-derived monocyte/macrophage progenitors. We found that calpain activity increased in response to RANKL in both cell types based on alpha-spectrinolysis and that mu-calpain, rather than m-calpain, was activated during RANKL-supported osteoclastogenesis in RAW 264.7 cells. Overexpression of mu-calpain clearly augmented RANKL-supported osteoclastogenesis in RAW 264.7 cells, thereby implicating its pivotal role in this process. Cell-permeable calpain inhibitors, including calpastatin and calpeptin, were sufficient to suppress RANKL-supported osteoclastogenesis based on decreased expression of the osteoclastogenic marker, matrix metalloproteinase 9, and the generation of tartrate-resistant acid phosphatase-positive multinucleated cells in both cell types. Calpain inhibitors suppressed NF-kappaB activation via inhibition of the cleavage of inhibitor of NF-kappaB(IkappaBalpha)in RAW 264.7 cells. Taken together, our findings suggest that mu-calpain is essential to the regulation of RANKL-supported osteoclastogenesis via NF-kappaB activation.

Zoledronate induces apoptosis in cells from fibro-cellular membrane of unicameral bone cyst (UBC).

Unicameral bone cyst (UBC) is a benign cystic lesion in children which is prone to fracture. Various treatments are available, but recurrence after different types of percutaneous injection therapy can cause bone destruction and pathologic fracture. The potential therapeutic effects of anti-resorptive agents, such as bisphosphonates, have not been investigated for UBC. The objective of this study was to characterize the cells from the fibro-cellular membrane of unicameral bone cyst (UBC cells) and to determine whether zoledronate, a nitrogen-containing bisphosphonate, could induce apoptosis in UBC cells. Flow cytometry and immunoblotting were performed in order to determine whether zoledronate induced apoptosis. Cells derived from normal human trabecular bones were used as controls against UBC cells to compare the effect of zoledronate in inducing apoptosis. Immunohisto/cytochemistry (IHC/ICC) and mini-array analyses were performed on tissues and cultured cells. Isolated peripheral blood mononuclear cells were incubated with conditioned media from the UBC cells to determine whether they are capable of inducing osteoclastogenesis. UBC membrane is composed of cells staining positively with CD68, SDF-1, STRO-1 and RANKL, but in vitro cells showed no staining with antibodies to CD68 and STRO-1, suggesting that there was a clonal selection of stromal cells during cell culture. UBC cells also express RUNX2 (runt-related transcription factor-2, core binding factor-1), a key transcription factor for osteoblastic differentiation. In addition, media collected from UBC cells induced a generation of multi-nucleated osteoclast-like cells of peripheral blood mononuclear cells. Zoledronate induced apoptosis of UBC cells in a dose-dependent manner. Apoptosis was evidenced by induction of the active cleaved form of caspase-3. The baseline apoptotic fractions were similar in UBC cells and trabecular bone cells. However, in the overall apoptotic fractions in this study, trabecular bone cells showed 17.2% of apoptosis, significantly lower than 24.2% of UBC cells (p-value=0.007). With the various zoledronate concentrations, mean apoptotic fractions of trabecular bone cells was 19.2%, significantly lower than 27.8% of UBC cells (p-value=0.040). With GGOH co-treatment in various zoledronate concentrations, 15.1% apoptosis was shown in trabecular bone cells, which was not significantly lower than 20.6% of UBC cells (p-value=0.076). This data suggests that zoledronate causes apoptosis in both UBC and trabecular bone cells by inhibition of the mevalonate pathway. In addition to the known anti-osteoclastogenic effect of bisphosphonates, the GGOH inhibitory effects of zoledronate were more prominent in UBC cells than trabecular bone cells, indicating their potential therapeutic role in UBC.

The molecular pathophysiology of subacromial bursitis in rotator cuff disease.

Little information exists on the molecular and biochemical pathophysiology of subacromial bursitis and rotator cuff disease. We investigated the pattern of expression of cytokines (interleukin [IL]-1beta, IL-1, IL-6, tumor necrosis factor [TNF] alpha, small inducible cytokines), metalloproteases, and cyclooxygenases in the subacromial bursa in patients with rotator cuff disease. Subacromial bursa specimens were prepared for molecular and biochemical analysis in patients undergoing shoulder surgery following an institutional review board-approved protocol. Specimens were analyzed for the presence of cytokines, metalloproteases, and cyclooxygenases by use of microarray for gene expression and immunohistocytochemistry. Microarray analysis for gene expression and immunohistochemistry demonstrated that the expression of several cytokine genes (TNF, IL-1alpha, IL-1beta, and IL-6) was increased in patients with subacromial bursitis compared with control specimens. Furthermore, the expression of metalloproteases (MMP-1 and MMP-9) and cyclooxygenases (COX-1 and COX-2) in the bursitis group was found to be increased as compared with controls. Although further investigation is required, these studies suggest that inflammation of the subacromial bursa does occur in patients with rotator cuff disease. These findings support the role of anti-inflammatory agents in the treatment of subacromial impingement and emphasize the importance of subacromial bursectomy to reduce inflammation in rotator cuff disease.

Recruitment of osteoclast precursors by stromal cell derived factor-1 (SDF-1) in giant cell tumor of bone.

Giant cell tumor (GCT) of bone is a unique bone lesion that is characterized by an excessive number of multinucleated osteoclasts. GCT consists of neoplastic stromal cells, multinucleated osteoclasts and their precursors, thus serving as a naturally occurring human disease model for the study of osteoclastogenesis. It still remains unclear how stromal cells of GCT recruit osteoclast precursors. In the present study, we characterized the cellular components of GCT and confirmed the presence of CD14(+)-monocytes/CD68(+)-macrophages and CD34(+)-hematopoetic stem cells that express CXCR4, a specific receptor for SDF-1; SDF-1 gene expression and presence of SDF-1 protein were confirmed by real time RT-PCR, in situ hybridization, and immunohistochemistry in the GCT tissue and cultured cells. SDF-1 was present at 25-50 ng/ml in the conditioned media from the GCT cultures, which is in the range of physiological chemotactic concentration. Migration of osteoclast precursors was 2.5-fold higher in response to GCT conditioned media compared to the control media; and migration was inhibited by an average of 36% with anti-SDF-1 neutralizing antibody or competing recombinant SDF-1. These results suggest that SDF-1 is one of the significant chemoattractant factors involved in the recruitment of hematopoietic osteoclast precursor cells during tumor-induced osteoclastogenesis.

Diagnostic value and limitations of fluorine-18 fluorodeoxyglucose positron emission tomography for cartilaginous tumors of bone.

BACKGROUND: A variety of imaging modalities are currently used for the preoperative evaluation of cartilage tumors. Although the anatomic details of the lesions are demonstrated well on computerized tomography and magnetic resonance images, those studies yield little information about the biologic activity of the tumors. In this study, we investigated the glucose metabolism of cartilage tumors measured by positron emission tomography and its correlation with histopathologic grades. METHODS: Thirty-five biopsy-proven cartilaginous tumors in twenty-seven patients were studied with plain radiographs, bone-scanning, magnetic resonance imaging, and positron emission tomography. The glucose metabolism in these cartilaginous tumors was measured quantitatively by calculating the maximal standardized uptake value of the region of interest. This value was then correlated with histopathologic grade, tumor size, recurrence, and metastasis. RESULTS: There were thirteen benign bone tumors, twelve grade-I chondrosarcomas, and ten high-grade (grade-II or III) chondrosarcomas. The mean maximal standard uptake values were 1.147 +/- 0.751 in the benign tumors, 0.898 +/- 0.908 in the grade-I chondrosarcomas, and 6.903 +/- 5.581 in the high-grade chondrosarcomas. There was no significant difference in these values between the benign cartilage tumors and the grade-I chondrosarcomas (p > 0.05). However, there was a significant difference between the low-grade (benign and grade-I) and high-grade chondrosarcomas (p = 0.009). Metastasis, but not tumor size or recurrence, was associated with a higher standard uptake value (p = 0.031). Two large pelvic grade-I chondrosarcomas demonstrated no radioisotope uptake on bone-scanning or on positron emission tomography. Positron emission tomography demonstrated grade-II and III metastatic lesions in the lung and other anatomic locations. When the cutoff for the standardized uptake value was set at 2.3 for grade-II or III chondrosarcomas, the positive predictive value was 0.82 (95% confidence interval, 0.48 to 0.97) and the negative predictive value was 0.96 (95% confidence interval, 0.77 to 1.00). CONCLUSIONS: Grade-II and III chondrosarcomas have a higher glucose metabolism than do low-grade cartilage tumors. However, the measurement of glucose metabolism by positron emission tomography alone cannot distinguish between benign and grade-I malignant cartilaginous tumors. It is important to understand the advantages and disadvantages of imaging modalities for accurate interpretation of results. Although positron emission tomography has limitations, it may be useful for predicting high-grade chondrosarcomas. LEVEL OF EVIDENCE: Diagnostic study, Level II-1 (development of diagnostic criteria on basis of consecutive patients [with universally applied reference "gold" standard]). See Instructions to Authors for a complete description of levels of evidence.

Bisphosphonates may reduce recurrence in giant cell tumor by inducing apoptosis.

Giant cell tumor of bone is an aggressive tumor characterized by extensive bone destruction and high recurrence rates. This tumor consists of stromal cells and hematopoietic cells that interact in an autocrine manner to produce tumoral osteoclastogenesis and bone resorption. This autocrine regulation may be disrupted by novel therapeutic agents. Nonspecific local adjuvant therapies such as phenol or liquid nitrogen have been used in the treatment of giant cell tumor, but specific adjuvant therapies have not been described. The bisphosphonates pamidronate and Zoledronate can induce apoptosis in giant cell tumor culture in a dose-dependent manner. We established giant cell tumor cultures from patients with extensive destruction of bone. One of the four cultures formed osteoclastlike giant cells in vitro after more than six passages without exogenous receptor activator of NF-kappaB ligand or macrophage colony stimulating factor. Annexin V staining, presence of active cleaved form of caspase-3, and disappearance of poly (ADP-ribose) polymerase on Western blotting indicated activation of apoptosis by bisphosphonates in giant cell tumor. These results indicate that topical or systemic use of pamidronate or zoledronate can be a novel adjuvant therapy for giant cell tumor by targeting osteoclastlike giant cells, mononuclear giant cell precursor cells, and the autocrine loop of tumor osteoclastogenesis.

Sources of polycyclic aromatic hydrocarbon exposure in non-occupationally exposed Koreans.

Urinary 1-hydroxypyrene (1-OHP), an exposure biomarker for polycyclic aromatic hydrocarbons (PAHs), was used to identify potential sources of PAH exposure for 660 Koreans who were not occupationally exposed to PAHs (65% male; 35% female; mean age, 36.5 +/- 11.1 years). In this study, 74% of subjects had detectable levels of urinary 1-OHP, with a concentration range of 0.001-3.796 microg/L (median, 0.079 microg/L). A backward elimination was conducted: five variables were selected with a significance level for removal of P < or = 0.1. The results of this study showed that residence in areas with relatively poor environmental conditions (Seoul and Suwon) was strongly associated with high concentrations of urinary 1-OHP (P = 0.007), while consumption of fried chicken and length of time spent outdoors had marginal positive associations with urinary 1-OHP levels (P = 0.06 and P = 0.09, respectively). Compared with the above three factors, tobacco smoking and urinary cotinine levels were poorly associated with urinary 1-OHP (P = 0.16 and 0.23, respectively). Pear consumption had an inverse association with urinary 1-OHP levels (P < 0.01). Individual variations in urinary 1-OHP concentrations were evaluated by considering the subjects' age, sex, and genetic polymorphisms in enzymes involved in the metabolism of PAHs. Among the individual variations, GSTT1-present subjects showed higher 1-OHP levels than GSTT1-absent subjects in cities having 10-microm particulate matter (PM(10)) levels and population density lower than those of Seoul and Suwon (P < 0.05). These epidemiological results suggest that the above factors that should be considered in preventing PAH exposure.

Genetic effects on urinary 1-hydroxypyrene levels in a Korean population.

Urinary 1-hydroxypyrene (1-OHP) has been used as a biomarker for assessing the level of exposure to environmental carcinogenic polycyclic aromatic hydrocarbons (PAHs). In order to perform the appropriate biological monitoring for examining the level of exposure to PAHs, this study investigated whether or not genetic polymorphisms of the metabolic enzymes, which might be involved in the metabolism of pyrene, affected the urinary 1-OHP levels in a population of 661 Koreans (male, 63%; female, 37%; mean age, 36.5 +/- 11.1 years) who were not occupationally exposed to PAHs. Urinary 1-OHP was detected in 76% of the subjects (range 0.001-3.8 micro g/l). Among the physical and lifestyle factors, cigarette-smoking was found to be associated with the urinary 1-OHP levels (P < 0.05). After adjusting for these factors, we found that the GSTT1 genotypes affected the urinary 1-OHP levels, i.e. the GSTT1 present subjects had approximately 1.5 times the urinary 1-OHP level than the GSTT1 null subjects (P < 0.05). In the case of the subjects who were also GSTM1 null, this trend became stronger, i.e. the GSTT1 present subjects had approximately 2 times the urinary 1-OHP level (P < 0.01). However, the genetic polymorphism of the other metabolic enzymes, cytochrome P-450 (CYP)1A1, CYP1B1 and GSTM1 alone, did not affect the urinary 1-OHP level. Therefore, this study suggests that the GSTT1 genetic polymorphism has the potential to affect the biological monitoring of PAHs with urinary 1-OHP, and might act as a genetic factor in PAH-related toxicity.