The relationship between serum prolidase activity and histone H3 protein levels and fibromyalgia

OBJECTIVE

Fibromyalgia (FM) is a clinical syndrome characterized by prominent physical and psychological impairment and widespread pain on both sides of the body, above and below the waist, and along the axial skeleton. It often causes sleep difficulties, memory impairment, mood changes, irritable bowel syndrome, and fatigue. Our study aimed to investigate the relationship between FM and prolidase (peptidase D) and histone H3 protein levels by comparing a patient group with a healthy control group.

PATIENTS AND METHODS

In total, 176 people were examined in our study, 88 of whom were healthy and 88 of whom had FM. Serum level was measured by ELISA. Then the results were analyzed using SPSS. All p < 0.05 were considered statistically significant.

RESULTS

A significant increase in the levels of prolidase was observed in the patient group compared with the control group (6.28-4.68, p <0.001). Histone H3 protein values were not significantly different between the patient and control groups (p=0.184). The ROC analysis indicated that prolidase was statistically significant in disease prediction (p<0.001, AUC: 0.795 (0.697-0.893), while histone H3 protein was statistically insignificant in predicting disease.

CONCLUSIONS

The results of the study show that prolidase activity may play a role in diagnosing FM. In addition, since no study like ours has been performed before, it can bring a new perspective to the literature.

The effects of drying and fermentation on the bioaccessibility of phenolics and antioxidant capacity of Thymus vulgaris leaves

Fresh thyme leaves (Thymus vulgaris L.) were dried at 45 °C for 5 h and naturally fermented at 20 °C in a brine solution containing salt and vinegar for 18 days. The ethanolic extracts of fresh (FT), dried (DT), and fermented-pickled (PT) thyme leaves were assessed in terms of total phenolic content (TPC), total flavonoid content (TFC), antioxidant capacity values and subjected to in vitro gastrointestinal digestion. TPC, TFC, and antioxidant capacity values of fermented thyme leaves were found significantly higher than of dried and fresh samples. The bioaccessibility index (BI) value for TPC and TFC was highest for PT and lowest for DT, indicating that both processes had different effects on the structure of phenolic compounds present in the thyme leaves. Similarly both Recovery and BI values of DPPH antioxidant capacity were highest for PT, but lowest for fresh samples. When CUPRAC assay was applied, the recovery % for FT and PT was similar, and the BI was higher for FT. Results showed that compared to the results of fresh thyme leaves, drying and pickling had a considerable effect on the initial phenolic compounds extracted and their fate during in vitro digestion.

Sirenomelia associated with Hypoplastic Left Heart in a Newborn

Sirenomelia, also known as “mermaid malformation/syndrome,” is a rare, serious congenital anomaly characterized by variable degrees of fusion of the lower limbs and associated with severe malformations of vertebral, genitourinary, cardiovascular system and single umbilical artery. The first pregnancy of a 25-year-old woman resulted in one twin born by Cesarian section at 32 weeks’ gestation, who was referred to our hospital with cyanosis, a congenital anomaly and respiratory distress. On physical examination, there was no urogenital region and anal fissure and gender was indeterminate. The arms were in adduction and wrist in flexion position with four fingers on the right hand and two fingers on the left hand. There was a single lower extremity with a webbed single foot and two toes consistent with sirenomelia type IV radiologically. Abdominal ultrasonography showed urogenital system agenesis and echocardiography detected hypoplastic left heart. However, the patient died 4 hours after birth. The other twin was followed for 1 week for nutrition and respiratory support and was then discharged without any problems.

Results from the Survey of Antibiotic Resistance (SOAR) 2011-13 in Turkey

OBJECTIVES

Data are presented from the Survey of Antibiotic Resistance (SOAR) for respiratory tract infection pathogens collected in 2011-13 from Turkey.

METHODS

MICs were determined using Etest(®). Susceptibility was assessed using CLSI, EUCAST and pharmacokinetic/pharmacodynamic (PK/PD) interpretive criteria.

RESULTS

Rates of antibiotic susceptibility were very low among 333 isolates of Streptococcus pneumoniae tested: penicillin 38% using CLSI (oral) and EUCAST breakpoints; erythromycin 51% using CLSI and EUCAST criteria; and cefuroxime 64.6% using CLSI and PK/PD and 46.9% using EUCAST. Of the isolates, >90% were susceptible to amoxicillin/clavulanic acid, ceftriaxone (except using EUCAST criteria: 76%), levofloxacin and high-dose intravenous penicillin. Among 339 Haemophilus influenzae isolates, 6.8% were β-lactamase positive while 9.1% were β-lactamase negative but ampicillin resistant (BLNAR) by CLSI (14.7% by EUCAST) criteria. Amoxicillin/clavulanic acid susceptibility was ∼90% by CLSI (with or without BLNAR adjustment, EUCAST and high-dose PK/PD) but lower, at 82.9%, by EUCAST with BLNAR adjustment. Levofloxacin susceptibility was 96% using all three breakpoints. Dramatic differences in rates of susceptibility, depending on the breakpoints used, were seen for cefaclor [94% by CLSI (86.4% BLNAR adjusted), 23% by PK/PD] and cefuroxime [97% by CLSI (89.1% BLNAR adjusted), 85% by PK/PD, 15% by EUCAST (13.0% BLNAR adjusted)]. Streptococcus pyogenes (n = 222) and Moraxella catarrhalis (n = 40) isolates remained highly susceptible to amoxicillin/clavulanic acid, cephalosporins and levofloxacin, with only erythromycin susceptibility dropping below 95% for S. pyogenes.

CONCLUSIONS

Overall, amoxicillin/clavulanic acid and levofloxacin were the most active antibiotics based on all three breakpoints against these pathogens. Although susceptibility was not universally low in Turkey, high resistance rates were found in S. pneumoniae and, when using PK/PD and EUCAST breakpoints, in other respiratory pathogens.

Apoptosis-Related Gene Expression in an Adult Cohort with Crimean-Congo Hemorrhagic Fever

Crimean-Congo Hemorrhagic Fever (CCHF) is a life threatening acute viral infection characterized by fever, bleeding, leukopenia and thrombocytopenia. It is a major emerging infectious diseases threat, but its pathogenesis remains poorly understood and few data exist for the role of apoptosis in acute infection. We aimed to assess apoptotic gene expression in leukocytes in a cross-sectional cohort study of adults with CCHF. Twenty participants with CCHF and 10 healthy controls were recruited at a tertiary CCHF unit in Turkey; at admission baseline blood tests were collected and total RNA was isolated. The RealTime ready Human Apoptosis Panel was used for real-time PCR, detecting differences in gene expression. Participants had CCHF severity grading scores (SGS) with low risk score (10 out of 20) and intermediate or high risk scores (10 out of 20) for mortality. Five of 20 participants had a fatal outcome. Gene expression analysis showed modulation of pro-apoptotic and anti-apoptotic genes that facilitate apoptosis in the CCHF patient group. Dominant extrinsic pathway activation, mostly related with TNF family members was observed. Severe and fatal cases suggest additional intrinsic pathway activation. The clinical significance of relative gene expression is not clear, and larger longitudinal studies with simultaneous measurement of host and viral factors are recommended.

Analysis of urine biomarkers for early determination of acute kidney injury in non-septic and non-asphyxiated critically ill preterm neonates

OBJECTIVE

We designed the present study to test the hypothesis that urinary biomarkers might predict acute kidney injury (AKI) development in non-septic and non-asphyxiated critically ill preterm infants. We evaluated urine (u) sistatin-C (uCys-C), kidney injury molecule-1 (uKIM-1) and neutrophil gelatinase associate lipocaline (uNGAL) as markers of AKI.

METHODS

Sixty-four preterm infants with gestational age between 28 and 32 weeks were included in this study. Biomarkers were measured on day of life (DOL) 1, 3, and 7.

RESULTS

uNGAL levels in the AKI group were significantly higher than in no-AKI group on DOL 1, 3 and 7 (p = 0.016, p = 0.007 and p = 0.0014, respectively).

CONCLUSIONS

uNGAL is sensitive, early, and noninvasive AKI biomarkers, increasing significantly in non-septic and non-asphyxiated critically ill preterm neonates.

Ceftaroline activity on certain respiratory tract and wound infection agents at the minimum inhibitory concentration level

INTRODUCTION

The aim of this study was to investigate the effectiveness of ceftaroline against agents frequently isolated from respiratory tract and wound infections.

METHODOLOGY

The study included a total of 250 strains isolated from various clinical specimens, among which were Streptococcus pyogenes, Streptococcus agalactiae, Streptococcus dysagalactiae, Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catharralis. The bacteria were identified using the matrix-assisted laser desorption/ionization time-of-flight method and conventional methods. The bacteria's antibiotic susceptibility was tested using appropriate broth microdilution. Mueller-Hinton broth with 4% lysed horse blood, Haemophilus test medium broth, and Mueller-Hinton broth were used. Ceftaroline fosamil results at the minimum inhibitory concentration (MIC) were evaluated using Clinical and Laboratory Standards Institute (CLSI) criteria. For quality assurance, E. coli ATCC 35218, S. aureus ATCC 29213, S. aureus ATCC 43300, S. pneumoniae ATCC 49619, H. influenzae ATCC 49766, H. influenzae ATCC 10211, and H. influenzae ATCC 49247 standard strains were used.

RESULTS

According to CLSI criteria, resistance was not detected in any strains. Due to the absence of CLSI criteria for M. catharralis, the susceptibility state for this bacterium was not evaluated. The various strains' MIC50-MIC90 values were as follows: for S. pyogenes, 0.015-0.06; for S. agalactiae, 0.03-0.125; for S. dysagalactiae, 0.03-0.06; for S. pneumoniae, 0.06-0.125; for H. influenzae, 0.015-0.125; and for M. catharralis, 0.5-1.

CONCLUSIONS

The results indicate that ceftaroline is quite effective against bacteria that are frequently isolated from respiratory tract and wound infections.

An ınvestigation into the in-vitro effectiveness of electrolyzed water against various microorganisms

The aim of this study was to investigate the in-vitro antimicrobial activity of usage and normal concentrations of electrolyzed water in hospital. In our study, the effects of different concentrations of electrolyzed water named Envirolyte® (Industries International Ltd., Estonia) on two gram positive, four gram negative standard strains and clinical isolates of four gram negative, two gram positive, one spore-forming bacillus and Myroides spp strains that lead to hospital infections were researched. The effects of different concentrations and different contact times of Envirolyte® electrolyzed water on cited strains were researched through method of qualitative suspension tests. Petri dishes fo bacteria have been incubated at 37°C 48 hours. Bactericidal disinfectant was interpreted to be effective at the end of the period due to the lack of growth. Solutions to which disinfectant were not added were prepared with an eye to control reproduction and controlcultures were made by using neutralizing agents. 1/1, 1/2, and 1/10 concentrations of Envirolyte® electrolyzed water were found to be effective on the bacteria that lead to hospital infections used during all test times. As a conclusion, based upon the results we acquired, it was observed that Envirolyte® electrolyzed water of 100% concentration would be convenient to be used for disinfection when diluted to a usage concentration of 1/10.

Evaluation of the efficacy of akacid plus® fogging in eradicating causative microorganism in nosocomial infections

OBJECTIVE

The novel polymeric guanidine Akacid Plus® is a member of the cationic family of disinfectants. The aim of the present study was to evaluate the activity of Akacid Plus® against bacteria which cause nosocomial infections and remain viable after contaminating the environment and determine the effects of organic materials to the activity.

METHODS

Closed room and control room were created for experimental disinfection. Bacterial suspensions of 0.5 McFarland were prepared from methicillin-resistant Staphylococcus aureus (MRSA), Acinetobacter baumannii and vancomycine-resistant Enterococcus faecium (VRE) strains. A 0.1 mL of each suspension was applied on the chipboard (25 cm(2)) and tile (25 cm(2)) test surfaces without albumin and with 2% albumin to simulate organic dirt, and the test surfaces were placed in the test and control rooms after drying. Before testing, cotton swab premoistened with serum physiologic was used to obtain samples from various surfaces in the environment and the samples were transferred onto 5% sheep blood agar for incubation at 37°C. Akacid Plus® solution at a concentration of 0.5% was nebulized with an aerosol applicator (Prowi-06, Germany) for 45 minutes. After a 2-hour waiting period, 1 mL neutralizing broth (Dey-Engley Neutralizing Broth, Fluka) was transferred on the test surfaces, and samples were collected with a swab from the test surfaces and various surfaces in the testing room and inoculated on 5% sheep blood agar for incubation at 37oC for 24 hours. At the end of the incubation period, number of colonies were evaluated on the control and test plates.

RESULTS

Although coagulase-negative staphylococci, Bacillus spp., and fungi were grown in cultured samples obtained from the environment of experimental laboratory, no growth was observed in the test plates after room disinfection with Akacid Plus®. After room disinfection, MRSA and A. baumannii were not detectable in the cultured media prepared from the test surfaces with or without albumin. The bacterial count for vancomyine-resistant E. faecium was reduced from 10(7) to 5×10(2) on surfaces without albumin and from 10(7) to 2.5×10(3) on surfaces with albumin. All test plates prepared from the surfaces in the control room showed abundant growth of the microorganism.

CONCLUSION

The nebulization of Akacid plus® solution at a concentration of 0.5% proved to be an efficient means of disinfection for the removal of pathogenic microorganisms that cause hospital outbreaks and use of isolation measures.

The olive leaf extract attenuates bacterial translocation and liver damage in obstructive jaundice

OBJECTIVES

The olive leaf extract (OLext) is known to possess many biological properties including a powerful antioxidant. This study aimed to investigate the protective effects of postoperative nutrition with OLext and glutamine on bacterial translocation (BT) and liver damage in obstructive jaundice.

MATERIALS AND METHODS

Totally, 50 rats were randomly divided into the five groups of 10 each. The common bile duct was ligated in all animals, excepting in the group 1. Postoperative nutrition was given to all groups for ten days. The rats in the Group 1 and 2 were fed a normal diet, Group 3 rats were fed an additional glutamine (1 g/kg/day), and Group 4 and 5 rats were fed an additional OLext (1 ml of 1/2 diluted and pure form/kg/day). Biochemical, microbiological and liver histopathological changes were evaluated.

RESULTS

BT in the Groups 3, 4, and 5 was significantly lower than in the Group 2. The values of aspartate transaminase (AST), alanine transaminase (ALT), γ-glutamyl transferase (γ-GT) and alkalen phosphatase (ALP) in blood were increased in obstructive jaundice, but the levels of these tests were statistically lower in glutamine and OLext groups when compared to the Group 2. Histopathological changes were observed low in the liver in OLext and glutamine groups.

CONCLUSIONS

The present data has demonstrated that the supplementation of olive leaf extract and glutamine reduce the incidence of BT and liver damage in obstructive jaundiced rats (Tab. 4, Fig. 1, Ref. 23).

In vitro antimicrobial activity of Medilox® super-oxidized water

Aim

Super-oxidized water is one of the broad spectrum disinfectants, which was introduced recently. There are many researches to find reliable chemicals which are effective, inexpensive, easy to obtain and use, and effective for disinfection of microorganisms leading hospital infections. Antimicrobial activity of super-oxidized water is promising. The aim of this study was to investigate the in-vitro antimicrobial activity of different concentrations of Medilox® super-oxidized water that is approved by the Food and Drug Administration (FDA) as high level disinfectant.

Material and methods

In this study, super-oxidized water obtained from Medilox® [Soosan E & C, Korea] device, which had been already installed in our hospital, was used. Antimicrobial activities of different concentrations of super-oxidized water (1/1, 1/2, 1/5, 1/10, 1/20, 1/50, 1/100) at different exposure times (1, 2, 5, 10, 30 min) against six ATCC strains, eight antibiotic resistant bacteria, yeasts and molds were evaluated using qualitative suspension test. Dey-Engley Neutralizing Broth [Sigma-Aldrich, USA] was used as neutralizing agent.

Results

Medilox® was found to be effective against all standard strains (Acinetobacter baumannii 19606, Escherichia coli 25922, Enterococcus faecalis 29212, Klebsiella pneumoniae 254988, Pseudomonas aeruginosa 27853, Staphylococcus aureus 29213), all clinical isolates (Acinetobacter baumannii, Escherichia coli, vancomycin-resistant Enterococcus faecium, Klebsiella pneumoniae, Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus, Bacillus subtilis, Myroides spp.), and all yeastsat 1/1 dilution in ≥ 1 minute. It was found to be effective on Aspergillus flavus at 1/1 dilution in ≥ 2 minutes and on certain molds in ≥ 5 minutes.

Conclusion

Medilox® super-oxidized water is a broad spectrum, on-site producible disinfectant, which is effective on bacteria and fungi and can be used for the control of nosocomial infection.

Colistin use in pediatric intensive care unit for severe nosocomial infections: experience of an university hospital

Background

The aim of this study was to investigate the efficacy and safety of colistin therapy in pediatric patients with severe nosocomial infections in pediatric intensive care unit.

Methods

The medical records of patients treated with colistin at a 200-bed university children hospital were reviewed.

Result

Thirty-one patients (male/female = 22/9; median age, 3 years; range, 3 months-17 years) received forty-one courses of colistin. The average dose of colistin was 4.9 ± 0.5 mg/kg/day and average treatment duration was 19.8 ± 10.3 days. Three patients who received concomitant nephrotoxic agent with colistin developed nephrotoxicity. Colistin treatment was well tolerated in other patients, and neurotoxicity was not seen in any patient. Favourable outcome was achieved in 28 (68.3%) episodes. Twelve patients died during the colistin therapy. Six of these patients died because of primary underlying disease. The infection-related mortality rate was found 14.6% in this study.

Conclusion

In our study, colistin therapy was found to be acceptable treatment option for the severe pediatric nosocomial infections caused by multi-drug resistant bacteria. However, the use of concomitant nephrotoxic drugs with colistin must be avoided and renal function test should be closely monitored.

Idiopathic portal hypertension during a catastrophic attack in a patient with primary antiphospholipid syndrome

A 43-year old male patient with hyponatremic hypertensive syndrome was diagnosed as catastrophic primary antiphospholipid syndrome (PAPS). He subsequently developed hepatosplenomegaly. The patient also carried thrombophilia- and haemochromatosis-associated gene mutations. Further investigations upon persistence of splenomegaly indicated development of idiopathic portal hypertension.

Influence of Extraction Time and Different Sage Varieties on Sensory Characteristics of a Novel Functional Beverage by RSM

An optimized formulation was developed for the preparation of an `ice-sage tea' which might be considered to be a new healthy functional product and designed as an alternative to other cold-served drinks in the market. A central composite design was used for modeling of the experiment with two independent variables (extraction time and blending ratios of two different sage varieties: Salvia officinalis (SO) and Salvia sclarea (SC)). Flavor profile of this novel product was developed using descriptive sensory analysis techniques; consumer acceptability of the product was also tested. Blending SO with SC was expected to increase the positive health effects of this novel product, while there was a limit for its concentration at increased extraction times. According to the evaluation of experienced panelists, blending common sage SO with SC did not reduce the overall likeability of this novel product at low extraction times. Statistically, just two models for astringency and overall impression were found to be acceptable by taking into consideration their regression coefficient and probability values. On the other hand, consumer test results showed that the samples prepared by blending SO with SC up to 25% might increase the likeability scores of the product when compared to the product without SC.

Nephrolithiasis associated with ceftriaxone therapy: a prospective study in 51 children

BACKGROUND

Ceftriaxone, a third generation cephalosporin, is widely used for treating infection during childhood. The kidneys eliminate approximately 33-67% of this agent, and the remainder is eliminated via the biliary system. Ceftriaxone may bind with calcium ions and form insoluble precipitate leading to biliary pseudolithiasis. The aim of this study was to assess whether ceftriaxone associated nephrolithiasis develops by the same mechanism, and whether this condition is dose related.

METHODS

The study involved 51 children with various infections. Of these, 24 were hospitalized with severe infection and received 100 mg/kg/day ceftriaxone divided into two equal intravenous doses. The other 27 patients received a single daily intramuscular injection of 50 mg/kg/day. Serum and urine parameters were evaluated before and after treatment, and abdominal ultrasonographic examinations were also carried out before and after treatment.

RESULTS

Serum urea, creatinine, and calcium levels were normal in all patients before and after treatment. Post-treatment ultrasound identified nephrolithiasis in four (7.8%) of the 51 subjects. The stones were all of small size (2 mm). Comparison of the groups with and without nephrolithiasis revealed no significant differences with respect to age, sex distribution, duration of treatment, or dose/route of administration of ceftriaxone. The renal stones disappeared spontaneously in three of the four cases, but were still present in one patient 7 months after ceftriaxone treatment.

CONCLUSIONS

Conclusions: The study showed that children taking a 7 day course of normal or high dose ceftriaxone may develop small sized asymptomatic renal stones. The overall incidence of nephrolithiasis in this study was 7.8%.

Elevated serum bone sialoprotein and osteopontin in colon, breast, prostate, and lung cancer

PURPOSE

Histological studies have shown that the two sialoproteins, bone sialoprotein (BSP) and osteopontin (OPN), are induced in multiple types of cancer. We have recently found that these proteins are bound in serum to complement factor H and that the complex must be disrupted to generate free protein to measure their total levels. We hypothesized that measuring total BSP and OPN levels would provide informative markers for the detection of cancer.

EXPERIMENTAL DESIGN

As a proof of concept study, serum from patients with diagnosed breast, colon, lung, or prostate cancer (n = 20 for each type) as well as normal serum (n = 77) were analyzed using competitive ELISAs developed for BSP and OPN. Sensitivity, specificity, as well as positive and negative predictive values were determined for each sialoprotein and cancer type. The relationship between sensitivity and specificity was profiled by receiver operating characteristic curves.

RESULTS AND CONCLUSIONS

Determined values for serum BSP in ng/ml were 285 +/- 19 for prostate, 373 +/- 19 for colon, 318 +/- 18 for breast, 155 +/- 11 for lung cancer sera, and 154 +/- 13 for normal sera. Values of OPN in ng/ml were 653 +/- 39 for prostate, 449 +/- 22 for colon, 814 +/- 53 for breast, 724 +/- 33 for lung, and 439 +/- 30 for normal sera. The assays provide a high degree of sensitivity and specificity that enables the detection of colon, breast, prostate, and lung cancer.

Human myeloma cells promote the recruitment of osteoblast precursors: mediation by interleukin-6 and soluble interleukin-6 receptor

Multiple myeloma is associated with the development of osteolytic bone disease characterized by a disruption to normal bone resorption and bone formation. Although studies have shown that myeloma cells produce factors that promote bone resorption little data are available examining the mechanism of decreased bone formation or the factors that mediate this effect. In the present study we describe a novel in vitro coculture system in which to investigate the effect of myeloma cells on osteoblast recruitment and differentiation. Under appropriate conditions mesenchymal stem cells were shown to differentiate into colonies of cells, a proportion of which show characteristics of osteoblasts, in that they express alkaline phosphatase activity and stain positively for collagen and calcium. The addition of the human myeloma cells JJN-3, RPMI-8226, or NCI-H929 to these cultures stimulated a significant increase in the total number of colonies (p < 0.005) and the proportion of osteoblastic colonies (p < 0.005). Media conditioned by these cells also were able to promote the formation of both total and osteoblastic colonies (p < 0.005). The addition of an antibody against the interleukin-6 receptor (IL-6R) blocked myeloma cell and myeloma cell-conditioned media induced osteoblast recruitment (p < 0.01). Furthermore, media conditioned by myeloma cells incubated with phorbol ester, which promotes IL-6R shedding, or a metalloproteinase inhibitor, which inhibits IL-6R shedding, were able to stimulate (p < 0.005) and inhibit osteoblast recruitment (p < 0.005), respectively. In addition, soluble IL-6R (sIL-6R) and IL-6 together, but not alone, were able to promote osteoblastic colony formation (p < 0.01). Taken together these data show that myeloma cells promote osteoblast recruitment by release of sIL-6R from myeloma cells.

Human myeloma cells promote the production of interleukin 6 by primary human osteoblasts

Interleukin-6 (IL-6) is an important growth and survival factor for myeloma cells. However, the identity of the cells producing IL-6 in vivo remains unclear. Myeloma cells are found closely associated with sites of active bone turnover, and cells of the osteogenic lineage, including bone marrow osteoprogenitors, osteoblasts and bone lining cells, may therefore be ideally placed to synthesize IL-6. We have examined the possibility that human osteogenic cells may produce IL-6 in response to stimulation by myeloma cells. Primary human osteoblasts (hOBs) were isolated from normal donors, co-cultured with the human myeloma cell lines, JJN-3, RPMI-8226 and NCI-H929, and the amount of IL-6 released was determined by enzyme-linked immunosorbent assay (ELISA). All myeloma cells stimulated a significant increase in the production of IL-6 when cultured with hOBs (P < 0.05). Prior fixation of hOBs completely abrogated release of IL-6 in the co-cultures. In contrast, fixed myeloma cells retained the ability to induce IL-6 production, suggesting that hOBs were the principal source of IL-6. Physical separation of myeloma cells from hOBs using transwell inserts caused a partial inhibition of IL-6 release (P < 0.05), whereas the addition of media conditioned by myeloma cells to cultures of hOBs stimulated a significant increase in IL-6 production (P < 0.05). hOBs secreted greater amounts of IL-6 than human bone marrow stromal cells (hBMSCs) (2.2- to 3.5-fold, P < 0.05), but incubating hBMSCs with dexamethasone to stimulate osteoblastic differentiation resulted in an increase in their ability to produce IL-6 (1.7- to 4. 8-fold, P < 0.05) and to respond to myeloma cells (P < 0.05). These data clearly indicate that cells of the osteoblast lineage release significant amounts of IL-6 in response to stimulation by myeloma cells and may contribute to the IL-6 that promotes the proliferation and survival of myeloma cells in vivo.