Clinical characteristics and outcomes of Clostridioides difficile infection in the intensive care unit: a KASID multi-centre study.

BACKGROUND: Despite the growing clinical and economic burden of Clostridioides difficile infection (CDI), data on CDI in the intensive care unit (ICU) in the Asia-Pacific region are lacking. METHODS: This retrospective study analysed 191 patients who were treated with CDI in the ICUs of three hospitals in South Korea from January 2017 to May 2021. Backward-stepwise multiple logistic regression was used to identify factors influencing the treatment response and mortality. RESULTS: Fifty-eight patients (30.4%) were considered immunocompromised. The mean Charlson comorbidity index was 5.65 ± 2.39 (10-year survival rate: 21%), the APACHE II score was 20.86 ± 7.78 (mortality rate: 40%), the ATLAS score was 5.45 ± 1.59 (cure rate: 75%), and the SOFA score was 7.97 ± 4.03 (mortality rate: 21.5%). Fifty-eight (30.4%) of the CDI cases were severe and 40 (20.9%) were fulminant. Oral vancomycin or oral metronidazole was the most frequently first-line treatments (N = 57; 32.6%). The 10-day response rate was 59.7% and the eight-week overall mortality rate was 41.4%. Fulminant CDI (OR 0.230; 95% CI 0.085-0.623) and each one-unit increment in the SOFA score (OR 0.848; 95% CI 0.759-0.947) were associated with treatment failure. High APACHE II (OR 0.355; 95% CI 0.143-0.880) and SOFA (OR 0.164; 95% CI 0.061-0.441) scores were associated with higher mortality. CONCLUSIONS: High-risk patients in the ICU had a higher mortality rate and a lower cure rate of CDI. Further research is required to provide more accurate prediction scoring systems and better clinical outcomes.

In vitro mitochondrial apoptosis of melanoma cells via immature Poncirus trifoliata fruit extract.

OBJECTIVE: Poncirus trifoliata (P. trifoliata) fruits exert phytotherapeutic effects, depending on their maturity level. However, the mechanism by which these phytotherapeutic effects are exerted remains undefined - especially in cancers. Therefore, in this study, we investigated the effects of the immature fruit extract of P. trifoliata on a B16 melanoma cell line. MATERIALS AND METHODS: The effect of immature P. trifoliata extract on B16 cells was evaluated by MTT assay, cell proliferation, FACScan analysis of cell cycles, confocal imaging analysis, nuclear (Hoechst) staining, apoptosis assay (Annexin V-fluorescein isothiocyanate/propidium iodide staining), and Western blot assay. The capacity of immature P. trifoliata extract to inhibit the invasion and migration of B16 cells was assessed using the scratch-wound assay and Matrigel migration assay. The effect of immature P. trifoliata extract on mitochondrial function was determined via the mitochondrial membrane potential assay, activity, and fraction and cytosol proteins. RESULTS: Treating B16 cells with a methanol extract of immature P. trifoliata (MEPT) significantly inhibited cell viability, migration, and invasiveness in a dose- (p<0.01) and time (p<0.01)- dependent manner. MEPT arrested the cells in the G1 phase of the cell cycle and led to the activation of the PI3K/AKT/p21 pathway. Furthermore, MEPT dose-dependently induced apoptosis in B16 cells by increasing the expression of the pro-apoptotic proteins Bax and Apaf-1, while decreasing the expression of the anti-apoptotic protein, Bcl-2. MEPT treatment also decreased mitochondrial membrane potential. CONCLUSIONS: Immature P. trifoliata extract inhibited the growth of melanoma cells by inducing cell apoptosis through mitochondrial pathways. Therefore, further research into immature P. trifoliata extract as a potential therapeutic compound for melanoma treatment is warranted.

Evaluation of abundance of artificial radionuclides in food products in South Korea and sources.

Food samples are collected nationwide from January 2016 to February 2017 and their contents of artificial radionuclides are measured to address the growing concerns regarding the radioactive contamination of food products in Korea. Specifically, 900 food samples are collected for this study and their contents of representative artificial radionuclides 134Cs, 137Cs, 239,240Pu, and 90Sr are analyzed. The analysis shows that the activity concentrations of 137Cs in fish range from minimum detectable activity (MDA) to 340 mBq/kg of fresh weight. The concentration factor (CF) determined for 137Cs as a measure of its bioavailability is calculated to be ca. 74 and found to be very similar to that (100) recommended by the International Atomic Energy Agency. With an MDA of <0.221 mBq/kg, the results reveal that 239,240Pu values in fish are below the MDA. The activity concentrations of 137Cs and 90Sr are lower than the MDA in both shellfish and seaweed, while the activity concentrations of 239,240Pu in shellfish range from 0.26 to 2.18 mBq/kg, and for seaweed samples range from 2.07 to 3.38 mBq/kg. The atom ratios of 240Pu/239Pu in shellfish caught at the Korean coast vary from 0.209 to 0.237, with a mean of 0.227. The higher 240Pu/239Pu atom ratio determined in shellfish is thought to be caused by the plutonium transported from the Pacific Proving Grounds rather than other sources such as the Fukushima nuclear power plant accident. The activity concentrations of 137Cs in mushrooms are found to vary from 1.0 to 21.4 Bq/kg, with the highest concentrations observed in the Oak (shiitake) and Sarcodon asparatus. 134Cs is detected in three mushroom specimens collected from Jeju Island and about 3-3.6% of 137Cs present in the wild mushrooms native to the Jeju Island are introduced as a result of the Fukushima nuclear plant accident. The annual effective doses of 137Cs received through consumption of mushrooms and fish are 2.0 × 10-4 mSv yr-1 and 3.9 × 10-5 mSv yr-1, and those values are negligible compared to the annual effective doses limit of 1 mSv yr-1.

Seasonally related effects on natural organic matter characteristics from source to tap in Korea.

In this study, natural organic matter (NOM) characteristics were investigated over three years of monthly monitoring to determine the effect of seasonal variations on NOM levels from source to tap. Liquid chromatography with organic carbon detection (LC-OCD) was used to determine NOM characteristics and the level of reduction of biodegradable dissolved organic carbon (BDOC). The average dissolved organic matter concentration in the source water (Lake Paldang, Korea) was not significantly different between summer and winter. However, the distribution of NOM components, such as biopolymers, building blocks, low molecular weight (MW) neutrals and acids, identified by LC-OCD, varied seasonally. While high MW NOM was preferentially removed by coagulation/sedimentation/rapid sand filtration (CSR), no seasonal effects were observed on the removal of high MW NOM. CSR and biological activated carbon (BAC) filtration showed a better efficiency of BDOC removal in winter and summer, respectively. High concentrations of chlorine used in the treatment plants in summer resulted in 10% higher DOC concentrations during disinfection. Overall NOM removal efficiencies from source to tap were 45% and 35% for summer and winter, respectively. Principal component analysis also indicated that seasonal variations (principal component 1) showed the strongest positive correlation with the overall performance of water treatment. The long-term monitoring of drinking water treatment processes showed that seasonal variations were important factors affecting NOM characteristics during water treatment.

Magnetic, structural, and electronic properties of the multiferroic compound FeTe2O5Br with geometrical frustration.

We report electron spin resonance (ESR), Raman scattering, and interband absorption measurements of the multiferroic FeTe2O5Br with two successive magnetic transitions at T(N1) = 11.0 K and T(N2) = 10.5 K. ESR measurements show all characteristics of a low-dimensional frustrated magnet: (i) the appearance of an antiferromagnetic resonance (AFMR) mode at 40 K, a much higher temperature than T(N1), and (ii) a weaker temperature dependence of the AFMR linewidth than in classical magnets, ΔH(pp)(T) ∝ T(n) with n = 2.2-2.3. Raman spectra at ambient pressure show a large variation of phonon intensities with temperature while there are no appreciable changes in phonon numbers and frequencies. This demonstrates the significant role of the polarizable Te4⁺ lone pairs in inducing multiferroicity. Under pressure at P = 2.12-3.04 GPa Raman spectra undergo drastic changes and absorption spectra exhibit an abrupt drop of a band gap. This evidences a pressure-induced structural transition related to changes of the electronic states at high pressures.

Application of finite element analysis in pre-operative planning for deformity correction of abnormal hip joints--a case series.

In experimental and clinical research, it is difficult to directly measure responses in the human body, such as contact pressure and stress in a joint, but finite element analysis (FEA) enables the examination of in vivo responses by contact analysis. Hence, FEA is useful for pre-operative planning prior to orthopaedic surgeries, in order to gain insight into which surgical options will result in the best outcome. The present study develops a numerical simulation technique based on FEA to predict the surgical outcomes of osteotomy methods for the treatment of slipped capital femoral epiphyses. The correlation of biomechanical parameters including contact pressure and stress, for moderate and severe cases, is investigated. For severe slips, a base-of-neck osteotomy is thought to be the most reliable and effective surgical treatment, while any osteotomy may produce dramatic improvement for moderate slips. This technology of pre-operative planning using FEA can provide information regarding biomechanical parameters that might facilitate the selection of optimal osteotomy methods and corresponding surgical options.

Association between the interleukin-18 promoter polymorphism and pulmonary tuberculosis in a Korean population.

OBJECTIVE: To examine the role of the -667G/T, -618A/C and -148G/C single nucleotide polymorphisms in the promoter region of the human interleukin (IL) 18 gene in the development of pulmonary tuberculosis (PTB), and its radiographic characteristics and severity. DESIGN: Differences in the allele and genotype distributions of the -667G/T, -618A/C, and -148G/C polymorphisms between 251 patients with PTB and 225 healthy controls, between patients with single- and multilobe involvement, and between patients with and without cavities were explored. Serum IL-18 levels were measured using an enzyme-linked immunosorbent assay. RESULTS: The -148G/G genotype was more common in patients with cavities than in those without (82.8% vs. 70.9%, P = 0.04), but an analogous trend was not observed for the -667G/T and -618A/C genotypes. However, there were no significant differences in allele and genotype distributions between patients with PTB and healthy controls, or between patients with single- and multilobe involvement (P > 0.05). Serum IL-18 levels were higher in patients with cavities (P = 0.01) and in patients with the -148G/G genotype (P = 0.02). CONCLUSION: Considering serum IL-18 levels, the -148G/G genotype is associated with a cavitary formation of PTB rather than its development.

Reducing ammonia emissions and volatile fatty acids in poultry litter with liquid aluminum chloride.

This study was a pen trial in which the effects of adding different rates of liquid aluminum chloride (AlCl(3)) on litter pH, total volatile fatty acids (VFAs), and ammonia (NH(3)) fluxes was evaluated. Liquid AlCl(3) treatments used in this study were sprayed on the rice hull surface at rates of 100 g, 200 g, and 300 g liquid AlCl(3)/kg rice hulls; untreated rice hulls served as controls. Litter pH, total VFAs, and NH(3) fluxes were all lowered (P< 0.05) by all of the liquid AlCl(3) treatments compared with controls during certain times of the 5 week study. However, there were no significant differences among treatments on litter pH at the end of the study (from 3 to 5 weeks) or NH(3) fluxes at beginning of the study (0 to 3 weeks). Total VFAs were reduced 16 %, 29 %, and 53 % by 100 g liquid AlCl(3)/kg rice hulls, 200 g liquid AlCl(3)/kg rice hulls, and 300 g liquid AlCl(3)/kg rice hulls, respectively. Liquid AlCl(3)additions reduced NH(3) fluxes by 35 %, 57 % and 67 %, respectively, at the low, medium and high rates. In summary, these results indicate that adding liquid aluminum chloride to rice hulls would be a useful tool in reducing the negative environmental impact of poultry litter. It should be noted that the decreased VFA production and NH(3) volatilization was chiefly associated with reduction in litter pH.

Fracture in long bones stabilised by telescopic intramedullary rods in patients with osteogenesis imperfecta.

We investigated the fracture-free survival of long bones stabilised by a telescopic intramedullary rod (TIMR) in patients with osteogenesis imperfecta with respect to the remodelling status of fracture or osteotomy sites and TIMR regions, in order to identify risk factors for fracture. A total of 44 femora and 28 tibiae in 25 patients with a mean age of 5.0 years (1.9 to 10.5) at presentation were studied. There were six patients with Sillence type I, five with type III, 13 with type IV and one with type V osteogenesis imperfecta. All received bisphosphonate treatment at the same stage during the mean follow-up of 7.3 years (0.5 to 18.1). The fracture-free survival was estimated at 6.2 years (95% confidence interval 5.1 to 7.3) by Kaplan-Meier analysis. More than half the fracture or osteotomy sites remained in a less-remodelled state at the latest follow-up or time of fracture. Of the 33 fractures, 29 (87.9%) occurred in long bones containing a less-remodelled site, and these fractures were located at this site. The relative fracture risk at the rod tip was significantly greater than in any other TIMR region (p < 0.001), and this was higher in bone segments having a less-remodelled site. This study shows a persistent fracture risk in TIMR-stabilised long bones, especially at less-remodelled fracture or osteotomy sites and at the rod tip.

Effects of dietary garlic powder and {alpha}-tocopherol supplementation on performance, serum cholesterol levels, and meat quality of chicken.

This study was carried out to evaluate the effects of supplementing diets with garlic powder and alpha-tocopherol on performance, serum cholesterol levels, and meat quality of chickens. Three hundred 1-d-old male broiler chicks were assigned to 5 diet treatments (0, 1, 3, and 5% garlic powder and 3% garlic powder + 200 IU of alpha-tocopherol/kg) with 3 replications of 20 birds for 35 d. There were no significant differences in broiler performance among the treatments. Moisture and crude ash contents of chicken thigh muscle were not different among all treatments, but dietary garlic powder and alpha-tocopherol supplementation resulted in significantly higher CP and lower crude fat contents in comparison with control (P < 0.05). Increasing the levels of garlic powder and applying garlic powder plus alpha-tocopherol significantly decreased total and low-density lipoprotein cholesterol and increased high-density lipoprotein cholesterol in broiler blood (P < 0.05). The pH and TBA reactive substances values were significantly reduced (P < 0.05) by the inclusion of garlic powder and alpha-tocopherol. However, no significant differences in water-holding capacity or shear force values were observed among the treatments. For broiler thigh muscle color, L* (lightness) values were decreased (P < 0.05), and a* (redness) and b* (yellowness) values were increased (P < 0.05) with the increased garlic powder levels and the combination of garlic powder and alpha-tocopherol. In terms of fatty acid composition in thigh muscle, unlike saturated fatty acid and total saturated fatty acid, dietary garlic powder or garlic powder plus alpha-tocopherol supplementation increased unsaturated fatty acid, total unsaturated fatty acid, and total unsaturated fatty acid:total saturated fatty acid ratios. These results suggest that 5% garlic powder or 3% garlic powder plus 200 IU of alpha-tocopherol antioxidant properties were effective for enhancing lipid and color stability.

Novel and recurrent TRPV4 mutations and their association with distinct phenotypes within the TRPV4 dysplasia family.

BACKGROUND: Mutations in TRPV4, a gene that encodes a Ca(2+) permeable non-selective cation channel, have recently been found in a spectrum of skeletal dysplasias that includes brachyolmia, spondylometaphyseal dysplasia, Kozlowski type (SMDK) and metatropic dysplasia (MD). Only a total of seven missense mutations were detected, however. The full spectrum of TRPV4 mutations and their phenotypes remained unclear. OBJECTIVES AND METHODS: To examine TRPV4 mutation spectrum and phenotype-genotype association, we searched for TRPV4 mutations by PCR-direct sequencing from genomic DNA in 22 MD and 20 SMDK probands. RESULTS: TRPV4 mutations were found in all but one MD subject. In total, 19 different heterozygous mutations were identified in 41 subjects; two were recurrent and 17 were novel. In MD, a recurrent P799L mutation was identified in nine subjects, as well as 10 novel mutations including F471del, the first deletion mutation of TRPV4. In SMDK, a recurrent R594H mutation was identified in 12 subjects and seven novel mutations. An association between the position of mutations and the disease phenotype was also observed. Thus, P799 in exon 15 is a hot codon for MD mutations, as four different amino acid substitutions have been observed at this codon; while R594 in exon 11 is a hotspot for SMDK mutations. CONCLUSION: The TRPV4 mutation spectrum in MD and SMDK, which showed genotype-phenotype correlation and potential functional significance of mutations that are non-randomly distributed over the gene, was presented in this study. The results would help diagnostic laboratories establish efficient screening strategies for genetic diagnosis of the TRPV4 dysplasia family diseases.

Effects of dietary alpha-tocopherol, selenium, and their different combinations on growth performance and meat quality of broiler chickens.

This study investigated the effect of different levels of dietary supplementation with alpha-tocopherol or Se, or both, on growth performance and meat quality of broiler chickens. A total of 270 broiler chickens were assigned to 6 dietary treatments (0, 50, 100, or 200 IU of supplemental alpha-tocopherol; 0.3 ppm supplemental Se; or 100 IU of alpha-tocopherol plus 0.3 ppm Se) with 3 replicates of 15 chickens per pen. Growth performance was recorded at 1 and 35 d. At the end of this experiment, 10 broilers per pen were slaughtered, and thigh muscle was dissected from each carcass and stored at 4 degrees C for 1, 3, 7, and 10 d. During the experimental period, none of the experimental treatments significantly influenced the growth performance of broilers. Thigh muscle pH values of all treatments decreased over time. The pH values for 1, 3, and 10 d were not affected by all treatments, but a statistical difference among treatments was observed at 7 d. Thiobarbituric acid reactive substances and total plate counts in all treatments increased with increasing storage time. In TBA reactive substances values, there were significant differences (P < 0.05) among treatments during the storage period. Differences among treatments in total plate count were found at d 7 and 10. In all treatments, L* (lightness) and b* (yellowness) values decreased over time, and a* (redness) values increased with storage time. Significant differences in all treatments were found for L* values at 3 d and a* values at 7 and 10 d of storage. Overall, these data indicate that compared with other treatments, supplementation with 200 IU of alpha-tocopherol or 100 IU of alpha-tocopherol plus 0.3 ppm Se were most effective in increasing lipid oxidative stability and delaying microbial growth and these activities were not associated with pH.

Shelf acetabuloplasty for children with Perthes' disease and reducible subluxation of the hip: prognostic factors related to hip remodelling.

We evaluated radiological hip remodelling after shelf acetabuloplasty and sought to identify prognostic factors in 25 patients with a mean age of 8.9 years (7.0 to 12.3) who had unilateral Perthes' disease with reducible subluxation of the hip in the fragmentation stage. At a mean follow-up of 6.7 years (3.2 to 9.0), satisfactory remodelling was observed in 18 hips (72%). The type of labrum in hip abduction, as determined by intra-operative dynamic arthrography, was found to be a statistically significant prognostic factor (p = 0.012). Shelf acetabuloplasty as containment surgery seems to be best indicated for hips in which there is not marked collapse of the epiphysis and in which the extruded epiphyseal segment slips easily underneath the labrum on abduction, without imposing undue pressure on the lateral edge of the acetabulum.

Effects of chemical treatments on pH and bacterial population in poultry litter: a laboratory experiment.

1. The goal of this study was to evaluate the effects of three chemical treatments on pH and bacterial populations (total aerobic bacteria and gram-negative bacteria) in poultry litter under laboratory conditions. 2. Litter obtained from poultry houses was treated with three chemical treatments (alum, AlCl(3) and FeSO(4)) at the same concentration (8 g/100 g litter), while untreated litter served as a control. The study was conducted for 3 weeks. 3. All of the chemical treatments reduced total aerobic bacteria (22 to 87% of the untreated control) and gram-negative bacteria (63 to 99% of the untreated controls) populations and lowered litter pH values (5.95 to 6.64). However, a significant difference in gram-negative bacteria did not exist among chemical treatments at 0, 1 and 2 weeks. 4. These results suggest that the reduction in total aerobic bacteria and gram-negative bacteria populations is highly related to a decrease in litter pH, and acidifying treatment (alum, AlCl(3) and FeSO(4)) of poultry litter may serve as a means to help the reduction in pathogen populations and to improve economical benefits under commercial production conditions.

Residual pelvic rotation after single-event multilevel surgery in spastic hemiplegia.

Our aim in this retrospective study of 52 children with spastic hemiplegia was to determine the factors which affected the amount of residual pelvic rotation after single-event multilevel surgery. The patients were divided into two groups, those who had undergone femoral derotation osteotomy and those who had not. Pelvic rotation improved significantly after surgery in the femoral osteotomy group (p < 0.001) but not in the non-femoral osteotomy group. Multiple regressions identified the following three independent variables, which significantly affected residual pelvic rotation: the performance of femoral derotation osteotomy (p = 0.049), the pre-operative pelvic rotation (p = 0.003) and the post-operative internal rotation of the hip (p = 0.001). We concluded that there is a decrease in the amount of pelvic rotation after single-event multilevel surgery with femoral derotation osteotomy. However, some residual rotation may persist when patients have severe rotation before surgery.

Effects of liquid aluminum chloride additions to poultry litter on broiler performance, ammonia emissions, soluble phosphorus, total volatile Fatty acids, and nitrogen contents of litter.

Recent studies have shown that the use of aluminum sulfate [alum, Al2(SO4)3.14H2O] and aluminum chloride (AlCl3) additions to animal manures are more effective than other chemicals in reducing ammonia (NH3) emissions and P solubility. Although the use of Al2(SO4)3.14H2O has been intensively used in the poultry industry for many years, no research has been conducted to evaluate the effect of liquid AlCl3 on these parameters. The objectives of this study were to determine the effects of applying liquid AlCl3 to poultry litter on 1) broiler performance, 2) NH3 fluxes, and 3) litter chemical characteristics, including soluble reactive P, total volatile fatty acids, and N content. Eight hundred broiler chicks were placed into 16 floor pens (50 birds/pen) in a single house for 6 wk. Liquid AlCl3 treatments were sprayed on the litter surface at rates of 100, 200, and 300 g of liquid AlCl3/kg of litter; un-treated litter served as controls. At the 2 lower rates, liquid AlCl3 treatments tended to improve weight gain and feed intake but had no effect on feed conversion or mortality, whereas the higher rate (300 g/kg of litter) had a negative effect on intake. Application of 100, 200, and 300 g of liquid AlCl3 reduced NH3 fluxes by 63, 76, and 76% during the 6-wk period, respectively, compared with the controls. Liquid AlCl3 additions reduced litter soluble reactive P contents by 24, 30, and 36%, respectively, at the low, medium, and high rates. Total volatile fatty acid contents (odor precursors) in litter were reduced by 20, 50, and 51%, respectively, with 100, 200, and 300 g of liquid AlCl3/kg of litter. Liquid AlCl3 additions increased total N, inorganic N, and plant available N contents in litter. These results indicate that liquid AlCl3 additions at the lower rates can provide significant positive environmental benefits to broiler operations.

Refracture after Ilizarov osteosynthesis in atrophic-type congenital pseudarthrosis of the tibia.

We investigated patterns of refracture and their risk factors in patients with congenital pseudarthrosis of the tibia after Ilizarov osteosynthesis. We studied 43 cases in 23 patients. Temporal and spatial patterns of refracture and refracture-free survival were analysed in each case. The refracture-free rate of cumulative survival was 47% at five years and did not change thereafter. Refracture occurred at the previous pseudarthrosis in 16 of 19 cases of refracture. The risk of refracture was significantly higher when osteosynthesis was performed below the age of four years, when the tibial cross-sectional area was narrow, and when associated with persistent fibular pseudarthrosis. Refracture occurs frequently after successful osteosynthesis in these patients. Delaying osteosynthesis, maximising the tibial cross-sectional area and stabilising the fibula may reduce the risk of refracture.

Morphometric changes in the acetabulum after Dega osteotomy in patients with cerebral palsy.

We carried out a morphometric analysis of the acetabulum following Dega osteotomy in patients with cerebral palsy using three-dimensional CT. We assessed 17 acetabula in 12 patients with instability of the hip. A Dega osteotomy and varus derotation femoral osteotomy were performed in all 17 hips. Three-dimensional CT scans were taken before and approximately one year after operation. Acetabular cover was evaluated using anterosuperior, superolateral and posterosuperior acetabular indices, and the change in the acetabular volume was calculated. Inter- and intra-observer reliability was assessed using the intraclass correlation coefficient. After the osteotomy, the anterosuperior, superolateral and posterosuperior cover had improved significantly towards the value seen in a control group. The mean acetabular volume increased by 68%.

Expression and role of interleukin-6 in distraction osteogenesis.

Distraction osteogenesis is a special form of bone healing in which well-controlled distraction stresses and consequent tensile strains within callus tissue induce very efficient new bone formation. Proinflammatory cytokines are involved during the early phase of fracture healing and callus remodeling. Temporal expression patterns of proinflammatory cytokines were assessed in Sprague-Dawley rat tibial models of distraction osteogenesis and acute lengthening, and only interleukin-6 (IL-6) was found to be specifically induced during the distraction phase. IL-6 immunoreactivity was detected not only in hemopoietic cells and osteoblasts but also in the spindle-shaped cells of the fibrous interzone, where most of the tensile strains are concentrated. In vitro study revealed that IL-6 did not affect the proliferation of C3H10T1/2 cells, mouse bone marrow stromal cells (MSCs), or MC3T3-E1 cells; but its blocking antibody reduced the proliferation of C3H10T1/2 cells and MSCs. The mRNA expression of COL1A1 and osteopontin were not changed by IL-6 or its blocking antibody, but the alkaline phosphatase activities of MC3T3-E1 cells were increased by IL-6 and decreased by its blocking antibody. These findings indicate that IL-6 is a proinflammatory cytokine that responds to tensile strain during distraction osteogenesis. IL-6 negatively affects the proliferation of primitive mesenchymal cells, whereas the differentiation of more mature osteoblastic lineage cells is enhanced by IL-6 in vitro. IL-6 appears to be one of the cytokines involved in the complex network of signal cascades evoked during distraction osteogenesis and may differentially affect immature and mature osteoblastic lineage cells.