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Background: Systemic amyloidosis is group of disorders characterized by the accumulation of insoluble proteins in tissues. The most common form of systemic amyloidosis is light chain amyloidosis, which results from the accumulation of misfolded immunoglobulins. The disease is progressive, with treatment targeted at the underlying plasma cell dyscrasia. Since essentially any organ system can be affected, the presentation is variable and delays in diagnosis are common. Given this diagnostic difficulty, we discuss four different manifestations of light chain amyloidosis., Case Presentations: In this case series, we discuss four cases of light chain amyloidosis. These include cardiac, hepatic, and gastrointestinal as well as autonomic and peripheral nerve involvement with amyloidosis. The patients in our series are of Caucasian background and include a  69-year-old female, a 29-year-old female, a 68-year-old male, and a 70-year-old male, respectively. The case discussions highlight variability in presentation and diagnostic challenges., Conclusions: Amyloidosis is a rare but serious disease that is often complicated by long delays in diagnosis. Morbidity and mortality can sometimes be limited if diagnosed earlier. We hope our real life cases will contribute to understanding and to early suspicion that can lead to early diagnosis and management., (© 2023. The Author(s).)

Purpose: To assess the feasibility of a trial evaluating whether hyperoncotic albumin, in addition to diuretics, improves diuresis and facilitates liberation from mechanical ventilation in critically ill adults., Materials and Methods: We randomized 46 hemodynamically stable patients with hypoalbuminemia, prescribed diuretics by treating clinicians, to receive 100 mL of 25% albumin or 0.9% saline placebo BID, for three days, in blinded fashion. We chose five feasibility measurements: enrolment of 50% of eligible patients, at least one patient/week; administration of study treatment within 2 h of diuretics in 85% of patients; completion of study regimen in 80% of patients; and avoidance of open label albumin in 85% of patients. Clinical outcomes included fluid balance, ventilator-free days, and mortality., Results: We randomized 85% of eligible patients. Eighty-four percent received study treatment within 2 h of diuretics, 69% received all doses of study treatment. Study treatment was held in the albumin and placebo groups because of no further need for diuresis (4 vs. 1), hypotension (2 v. 4), and albumin > 35 (1 v. 0). Twenty percent of patients received open-label albumin. Clinical outcomes were similar between groups., Conclusions: The current study design did not demonstrate feasibility, but can inform the design of a definitive trial., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background: Family members may wish to be present during resuscitation of loved ones, despite concerns that they may interfere with the resuscitation or experience psychological harm., Methods: We conducted a systematic review to determine whether offering family presence during resuscitation (FPDR) affected patient mortality, resuscitation quality, or family member psychological outcomes. We searched multiple databases up to January 2014 for studies comparing FPDR to usual care. Two reviewers independently assessed eligibility, risk of bias, and extracted data. Data from randomized controlled trial (RCTs) at low or uncertain risk of bias were eligible for pooling. Quality of evidence was assessed using GRADE., Results: Three RCTs evaluated the offering of FPDR in adults, finding no differences in resuscitation duration, prehospital/emergency room mortality (odds ratio [OR] 0.80, 95 % confidence interval [CI] 0.54-1.19), or 28-day mortality (OR 1.24, 95 % CI [0.50-3.03]). Hospital Anxiety and Depression Scale scores for anxiety (mean difference [MD] -0.99, 95 % CI [-1.77, -0.22]) and depression (MD -1.00, 95 % CI [-1.78, -0.23]), along with Impact of Events Scale intrusion score (MD -1.00, 95 % CI [-1.96, -0.03]), were better in family members offered FPDR. One RCT evaluated FPDR in pediatric patients, finding no mortality differences at 28 days (OR 0.30; 95 % CI [0.11-0.79]), but did not report psychological outcomes in family members., Conclusions: Moderate-quality evidence suggests the offering of FPDR does not affect adult resuscitation outcomes and may improve family member psychological outcomes. Low-quality evidence suggests FPDR does not affect pediatric resuscitation outcomes. The generalizability of these findings outside the prehospital and emergency room setting is limited due to the absence of trials in other health care settings.

Background: An experimenter controlled form of reflection has been shown to improve the detection and correction of diagnostic errors in some situations; however, the benefits of participant-controlled reflection have not been assessed., Objective: The goal of the current study is to examine how experience and a self-directed decision to reflect affect the accuracy of revised diagnoses., Design: Medical residents diagnosed 16 medical cases (pass 1). Participants were then given the opportunity to reflect on each case and revise their diagnoses (pass 2)., Participants: Forty-seven medical Residents in post-graduate year (PGY) 1, 2 and 3 were recruited from Hamilton Health Care Centres., Main Measures: Diagnoses were scored as 0 (incorrect), 1 (partially correct) and 2 (correct). Accuracies and response times in pass 1 were analyzed using an ANOVA with three factors-PGY, Decision to revise yes/no, and Case 1-16, averaged across residents. The extent to which additional reflection affected accuracy was examined by analyzing only those cases that were revised, using a repeated measures ANOVA, with pass 1 or 2 as a within subject factor, and PGY and Case or Resident as a between-subject factor., Key Results: The mean score at pass 1 for each level was PGY1, 1.17 (SE 0.50); PGY2, 1.35 (SE 0.67) and PGY3, 1.27 (SE 0.94). While there was a trend for increased accuracy with level, this did not achieve significance. The number of residents at each level who revised at least one diagnosis was 12/19 PGY1 (63 %), 9/11 PGY2 (82 %) and 8/17 PGY3 (47 %). Only 8 % of diagnoses were revised resulting in a small but significant increase in scores from Pass 1 to 2, from 1.20/2 to 1.22 /2 (t = 2.15, p = 0.03)., Conclusions: Participants did engage in self-directed reflection for incorrect diagnoses; however, this strategy provided minimal benefits compared to knowing the correct answer. Education strategies should be directed at improving formal and experiential knowledge.

Background: Recent evidence suggests that patient outcomes are not affected by the offering of family presence during resuscitation (FPDR), and that psychological outcomes are neutral or improved in family members of adult patients. The exclusion of family members from the resuscitation area should, therefore, be reassessed., Objective: The present Canadian Critical Care Society position paper is designed to help clinicians and institutions decide whether to incorporate FPDR as part of their routine clinical practice, and to offer strategies to implement FPDR successfully., Methods: The authors conducted a literature search of the perspectives of health care providers, patients and families on the topic of FPDR, and considered the relevant ethical values of beneficence, nonmaleficence, autonomy and justice in light of the clinical evidence for FPDR. They reviewed randomized controlled trials and observational studies of FPDR to determine strategies that have been used to screen family members, select appropriate chaperones and educate staff., Results: FPDR is an ethically sound practice in Canada, and may be considered for the families of adult and pediatric patients in the hospital setting. Hospitals that choose to implement FPDR should develop transparent policies regarding which family members are to be offered the opportunity to be present during the resuscitation. Experienced chaperones should accompany and support family members in the resuscitation area. Intensive educational interventions and increasing experience with FPDR are associated with increased support for the practice from health care providers., Conclusions: FPDR should be considered to be an important component of patient and family-centred care.

Background: Fluid retention is a common complication of critical illness. It typically results from large-volume fluid infusions during acute resuscitation and is worsened by hypoalbuminemia. Recognized as edema, fluid retention is important for its association with delayed weaning and increased mortality. The standard treatment is the administration of diuretics, with or without albumin. We hypothesize that intravenous 25% albumin plus furosemide, by comparison with furosemide alone, improves diuresis, oxygenation, and hemodynamic stability in the deresuscitation of critically ill, hypoalbuminemic patients. We propose a pilot study to determine the feasibility of a trial to investigate this hypothesis., Methods/design: FADE is a single-center, parallel, pilot randomized controlled trial. We aim to allocate 50 hemodynamically stable, hypoalbuminemic adult patients receiving diuresis to treatment with either 100 ml of either 25% albumin or normal saline placebo twice daily, for a total of six doses. Diuretics are to be prescribed by the caregiving team at least twice daily, and administered within 2 hours following study treatment. Patients, intensive care unit (ICU) clinicians, data collectors, and outcome adjudicators will be blinded to treatment allocation. Feasibility outcome measures include the proportion of patients receiving albumin within 2 hours of diuretic, the proportion of patients receiving the full six doses of study treatment, the proportion of patients who receive open label 25% albumin, and the rate of recruitment. Physiologic, laboratory, and clinical data are collected until discharge from the ICU or until 30 days., Discussion: This is the first randomized trial to assess the use of hyperoncotic albumin in addition to diuretics in a general ICU population. Should this pilot study demonstrate feasibility, the primary outcome measure of the larger clinical trial will be the number of ventilator-free days, with secondary clinical outcome measures of duration of mechanical ventilation, length of ICU stay, episodes of hemodynamic instability and mortality. The addition of 25% albumin to standard diuretic therapy is a promising treatment in the post-resuscitation care of the critically ill patient., Trial Registration: ClinicalTrials.gov NCT02055872; ISRCTN70191881.

Background: The background of this study is to determine whether the addition of intravenous colloid to diuretic therapy, in comparison to diuretic therapy alone, improves diuresis and oxygenation and prevents intravascular volume depletion in intensive care unit (ICU) patients without shock., Methods: We searched MEDLINE, Embase, Cochrane Register of Controlled Trials, Google Scholar, conference abstracts of ACCP, SCCM, ATS, and references of relevant articles. Randomized controlled trials (RCTs) of adult ICU patients, not in shock (defined as patients on low dose or no vasopressors, without need for IV fluid bolus or blood transfusion within 24 h), comparing intravenous colloid therapy (human albumin, plasma, synthetic starches, or gels) plus diuretic to control (diuretic alone, or diuretic plus placebo). Two reviewers independently applied eligibility criteria, assessed quality, and extracted data., Results: Seven hundred fifty five studies were found in the initial search; 14 were deemed relevant; 2 were found to be eligible. There was good agreement between reviewers for study relevance (k = 0.869) and eligibility (k = 0.811). One study of heart failure patients showed no evidence of improved mean or hourly urine output in the group receiving albumin. The second studied patients hypoproteinemic with ARDS and demonstrated an improved fluid balance in 3 days, improved oxygenation status, and improved serum albumin level in patients treated with albumin. No significant differences were found for other outcomes. No studies evaluating colloids other than albumin were found., Conclusions: Our review is limited by the small number of high-quality RCTs available to study this clinical question, both of which only studied albumin. High-quality RCTs are required to evaluate the effect of albumin as well as other colloids as an adjunct to diuresis in a general ICU population.

Purpose: To evaluate the accuracy of systemic antibiotic use statistics, based on the reimbursement data of the Emilia-Romagna Region (Italy), focusing on agents prescribed for urinary tract infections., Methods: Reimbursement data were obtained from the drug prescription database that includes all outpatient drug prescriptions reimbursed by the Regional Health Service in 2007. Reimbursements were compared to sales data, provided by International Medical Statistics (IMS) Health., Results: The reimbursement data of the Emilia-Romagna Region significantly underestimates the actual use of systemic antibiotics when compared to sales. The overall underestimation of antibiotic use is 19%, ranging from 7% for second-third-generation cephalosporins to 98% for nitrofurantoin. Considering agents prescribed for urinary tract infections (UTIs), use of nitrofurantoin and sulfamethoxazole-trimethoprim are more underestimated while fluoroquinolones and fosfomycin are less underestimated than the average for systemic antibiotics., Conclusions: Sales data from community pharmacies are important for accurate estimation of systemic antibiotic use in Emilia-Romagna especially for agents, such as nitrofurantoin, purchased without reimbursement in most cases., ((c) 2009 John Wiley & Sons, Ltd.)

Thrombocytopenia has been consistently reported following the administration of adenoviral gene transfer vectors. The mechanism underlying this phenomenon is currently unknown. In this study, we have assessed the influence of von Willebrand Factor (VWF) and P-selectin on the clearance of platelets following adenovirus administration. In mice, thrombocytopenia occurs between 5 and 24 hours after adenovirus delivery. The virus activates platelets and induces platelet-leukocyte aggregate formation. There is an associated increase in platelet and leukocyte-derived microparticles. Adenovirus-induced endothelial cell activation was shown by VCAM-1 expression on virus-treated, cultured endothelial cells and by the release of ultra-large molecular weight multimers of VWF within 1 to 2 hours of virus administration with an accompanying elevation of endothelial microparticles. In contrast, VWF knockout (KO) mice did not show significant thrombocytopenia after adenovirus administration. We have also shown that adenovirus interferes with adhesion of platelets to a fibronectin-coated surface and flow cytometry revealed the presence of the Coxsackie adenovirus receptor on the platelet surface. We conclude that VWF and P-selectin are critically involved in a complex platelet-leukocyte-endothelial interplay, resulting in platelet activation and accelerated platelet clearance following adenovirus administration.

Besides the well-known activities of the prototypical inflammatory cytokines (IL-1beta, TNFalpha), a role for chemokines and their receptors in cartilage degradation in osteoarthritis has recently been reported. Human chondrocytes can produce CC and CXC chemokines and express chemokine receptors for both chemokine subfamilies. Engagement of these receptors can induce the release of matrix degrading enzymes such as matrix metalloproteinases 1, 3, and 13, and N-acetyl-beta-D-glucosaminidase. Furthermore GROalpha, a CXC chemokine acting on CXCR2, can activate an apoptotic pathway in chondrocytes that leads to chondrocyte cell death. These findings suggest that chemokines can act as an autocrine or paracrine loop on chondrocytes and can contribute to many pathophysiological patterns present in osteoarthritis. Chemokines and their downstream signaling pathways can be considered novel therapeutic targets in osteoarthritis.

Objective: To extend the study of the chemokine receptor repertoire on human chondrocytes to receptors with reported housekeeping functions (CXCR3, CXCR4, CXCR5, and CCR6) and to evaluate whether ligands of these receptors play a role in chondrocyte phenotype modulation and proliferation., Methods: Chemokine receptor expression was determined by flow cytometry. Subcultures of chondrocytes were collected and fixed at confluence or during the exponential phase of growth and analyzed for chemokine receptor modulation. The effects of chemokines on isolated cells as well as chondrocytes cultured within an intact extracellular matrix were investigated. Isolated human chondrocytes were stimulated with 100 nM chemokines (monokine induced by interferon-gamma, stromal cell-derived factor 1alpha [SDF-1alpha], B cell-attracting chemokine 1 [BCA-1], or macrophage inflammatory protein 3alpha), and conditioned media were assessed for matrix-degrading enzyme contents (matrix metalloproteinases [MMPs] 1, 3, and 13, and N-acetyl-beta-D-glucosaminidase [NAG]). Cell proliferation and phenotype modulation were evaluated by bromodeoxyuridine incorporation and cathepsin B production. Induction of cell proliferation was assessed in cartilage explants by immunodetection of the proliferation-associated antigen S100A4., Results: CXCR3, CXCR4, CXCR5, and CCR6 were detected on human chondrocytes. CXCR3 and CXCR4 expression was increased in exponentially growing chondrocyte subcultures. Ligands of all receptors enhanced the release of MMPs 1, 3, and 13. Release of NAG and cathepsin B was significantly higher in chemokine-stimulated cultures than in unstimulated cultures. SDF-1alpha and BCA-1 also induced DNA synthesis and chondrocyte proliferation, as was shown by the up-regulation of S100A4 in cartilage explants as well., Conclusion: Our findings extend the repertoire of functional responses elicited by the activity of chemokines on chondrocytes and open new avenues in our understanding of the control of chondrocyte differentiation status by chemokines and their receptors.

Objective: To evaluate the apoptotic effect of the chemokine growth-related oncogene alpha (GROalpha), which we recently reported to be up-regulated in osteoarthritis (OA) chondrocytes. Chondrocyte apoptosis is considered to be a major determinant of cartilage damage in OA, a disease resulting from the aberrant production of inflammatory mediators (cytokines and chemokines) and effectors (matrix metalloproteinases and reactive oxygen and nitrogen species) by chondrocytes., Methods: We investigated the apoptotic effect of GROalpha on isolated human cells and on in vitro-cultured cartilage explants by conventional methods (morphology, detection of DNA fragmentation in situ and in solution, exposure of phosphatidylserine) and by analysis of "early" biochemical events (plasma membrane depolarization, activation of caspase 3, and phosphorylation of c-Jun N-terminal kinase/stress-activated protein kinase)., Results: We clearly demonstrated that GROalpha was able to initiate a series of morphologic, biochemical, and molecular changes that led to chondrocyte apoptosis. Moreover, we found that additional signals delivered from the extracellular matrix (ECM) were essential in the control of chondrocyte susceptibility to GROalpha-induced apoptosis, since cell death was detected only when cells were stimulated after reestablishment of their proper interactions with the ECM, or in cartilage explant samples with reduced ECM, as indicated by decreased Safranin O staining., Conclusion: GROalpha can induce apoptosis in articular chondrocytes, and the induction is dependent upon additional signals from the ECM. These findings are relevant to understanding the pathogenesis of OA, in view of the availability of the GROalpha chemokine in the joint space in the course of this rheumatic disease.

Osteoarthritis and rheumatoid arthritis are characterized by focal loss of cartilage due to an up-regulation of catabolic pathways, induced mainly by pro-inflammatory cytokines, such as interleukin-1 (IL-1) and tumour necrosis factor alpha (TNFalpha). Since reactive oxygen species are also involved in this extracellular-matrix-degrading activity, we aimed to compare the chondrocyte oxidative status responsible for cartilage damage occurring in primarily degenerative (osteoarthritis) and inflammatory (rheumatoid arthritis) joint diseases. Human articular chondrocytes were isolated from patients with osteoarthritis or rheumatoid arthritis, or from multi-organ donors, and stimulated with IL-1beta and/or TNFalpha. We evaluated the oxidative stress related to reactive nitrogen and oxygen intermediates, measuring NO(-)(2) as a stable end-product of nitric oxide generation and superoxide dismutase as an antioxidant enzyme induced by radical oxygen species. We found that cells from patients with osteoarthritis produced higher levels of NO(-)(2) than those from patients with rheumatoid arthritis. In addition, IL-1beta was more potent than TNFalpha in inducing nitric oxide in both arthritides, and TNFalpha alone was almost ineffective in cells from rheumatoid arthritis patients. We also observed that the intracellular content of copper/zinc superoxide dismutase (Cu/ZnSOD) was always lower in rheumatoid arthritis chondrocytes than in those from multi-organ donors, whereas no differences were found in intracellular manganese SOD (MnSOD) or in supernatant Cu/ZnSOD and MnSOD levels. Moreover, intracellular MnSOD was up-regulated by cytokines in osteoarthritis chondrocytes. In conclusion, our results suggest that nitric oxide may play a major role in altering chondrocyte functions in osteoarthritis, whereas the harmful effects of radical oxygen species are more evident in chondrocytes from patients with rheumatoid arthritis, due to an oxidant/antioxidant imbalance.

We have previously detected autoantibodies against topoisomerase II alpha (anti-topo II alpha) in sera from patients with idiopathic pulmonary fibrosis. To determine whether anti-topo II alpha is also present in systemic sclerosis (SSc) patients with pulmonary involvement, we screened sera from 92 patients and 34 healthy controls. Presence of anti-topo II alpha was investigated with respect to clinical and serological features, including the frequencies of HLA class I and II alleles. Anti-topo II alpha was detected in 20/92 (21.7%) patients. No association was found with either anti-topoisomerase I (Scl-70 or anti-topo I) or anti-centromere antibodies. However, anti-topo II alpha was associated with the presence of pulmonary hypertension (PHT) (as opposed to pulmonary fibrosis), and with a decrease of carbon monoxide diffusing capacity. Anti-topo II alpha was strongly associated with the presence of the class I antigen HLA-B35. No significant association was found with HLA class II antigens. HLA-B35 also turned out to be associated with the presence of PHT. These results indicate that in SSc patients, the presence of anti-topo II alpha is associated with PHT, and that the simultaneous presence of HLA-B35 seems to add to the risk of developing PHT.

Objective: Human chondrocytes produce different C-X-C and C-C chemokines under basal conditions and upon activation with proinflammatory cytokines. We investigated whether human chondrocytes also have chemokine receptors and examined the effects of chemokines on chondrocyte activity., Methods: The expression of chemokine receptors was determined by immunochemical analysis of frozen sections from normal and osteoarthritic cartilage and by flow cytometry of isolated cells. The messenger RNA expression for chemokine receptors was studied by reverse transcriptase-polymerase chain reaction. Isolated chondrocytes were stimulated with different chemokines, and the responses were evaluated by assaying the release of matrix metalloprotease 3 (MMP-3) and of the lysosomal enzyme N-acetyl-beta-D-glucosaminidase in the supernatants., Results: A wide variety of chemokine receptors (CCR-1, CCR-2, CCR-3, CCR-5, CXCR-1, and CXCR-2) was detected on human chondrocytes. Interaction of these receptors with the corresponding ligands induced the release of MMP-3. This response was abrogated by pretreatment of the cells with Bordetella pertussis toxin, demonstrating involvement of G proteins of the Gi type. The response decreased in the presence of cycloheximide, indicating dependence on protein synthesis. Chemokines also induced the exocytosis of N-acetyl-beta-D-glucosaminidase, which was prevented by receptor blockage with anti-CCR-3 and by treatment with B pertussis toxin. Chondrocytes obtained from osteoarthritic tissue showed an increased expression of CCR-3 and possibly of CXCR-1, and an augmented release of matrix-degrading enzymes compared with chondrocytes from normal donors., Conclusion: Our findings suggest the existence in human chondrocytes of a novel catabolic pathway, primed by chemokines and their receptors, that leads to the breakdown of cartilage matrix components.

Chemokines play a key role in modulating leukocyte functions at sites of inflammation. To assess chondrocyte contribution to the chemotactic environment of inflamed joints the intracellular content of CC and CXC chemokines was investigated. IL-8, GROalpha, MCP-1, RANTES, MIP-1alpha and MIP-1beta expression was evaluated by flow cytometric analysis and RT-PCR in chondrocytes isolated from cartilage specimens obtained from patients with osteoarthritis and rheumatoid arthritis and multiorgan donors as normal controls. All the chemokines except RANTES were found in normal chondrocytes, with different degrees of staining intensity. In osteoarthritis and rheumatoid arthritis patients, an enhancement of IL-8, GROalpha, MIP-1alpha and MIP-1beta was observed.

Objective: To evaluate the sites of expression of interleukin-1beta (IL-1beta), tumor necrosis factor alpha (TNFalpha), and inducible nitric oxide synthase (iNOS) in patients with inflammatory and degenerative joint diseases., Methods: Cytokines and iNOS were detected by immunohistochemistry analysis of synovial and cartilage biopsy specimens obtained at knee arthroscopy in patients with rheumatoid arthritis (RA), psoriatic arthritis (PsA), osteoarthritis (OA), and traumatic knee arthritis. Cytokine and iNOS expression was quantified using computerized image analysis., Results: IL-1beta, TNFalpha, and iNOS were highly expressed by synovial cells (lining layer cells, infiltrating leukocytes, endothelial cells) from patients with inflammatory arthritides and significantly less by synovial cells from patients with OA and traumatic arthritis. In contrast, the latter patients showed high chondrocyte expression of cytokines and iNOS while RA and PsA patients had only minor chondrocyte positivity. In both joint compartments, IL-1beta expression, TNFalpha expression, and iNOS expression were strongly correlated., Conclusion: The enhanced and coordinated expression of IL-1beta, TNFalpha, and iNOS by chondrocytes strongly supports the hypothesis that chondrocytes are the major site of production of mediators of inflammation in human OA, thus playing a primary role in the pathogenesis of this disease.

Autoantibodies against DNA topoisomerase II alpha have been identified in the sera of patients with idiopathic pulmonary fibrosis (IPF). To map topoisomerase II autoepitopes, we tested by ELISA and immunoblotting the IPF anti-topoisomerase II-positive sera against a series of recombinant proteins which covered the full length of topoisomerase II alpha. Specific patterns of reactivity were observed, indicating the existence of multiple epitopes on topoisomerase II, either highly complex or conformational/discontiguous or conformational/contiguous ones. The latter resided in amino acid residues 854-1147 and 1370-1447. A detailed analysis of these regions was undertaken, but we were not able to pinpoint a sequential peptide-sized epitope, or any significant homology with foreign pathogens. Further, we observed a significant correlation between the progression from a contiguous to a quaternary/tertiary structure-dependent autoepitope and the disease duration but not with the disease severity. Therefore, this result supports the hypothesis that anti-topoisomerase II autoreactivity evolves following an antigen-driven process.

Oxidative stress has been frequently implicated in the initiation and promotion phases of carcinogenesis. Antioxidant enzymes, which can antagonize this process, are lowered in a number of malignancies even though different findings have been reported in the literature. It has been shown that tumors have less copper/zinc superoxide dismutase (Cu/Zn SOD) in comparison with the more metabolically active tissues, but there is a large overlap between normal and tumor tissue. In order to examine the relationship between osteosarcoma at different degrees of proliferation and differentiation and Cu/Zn SOD levels, four different human ostosarcoma cell lines: HOS, U-2 OS, MG63, Saos-2 were studied for their production and release of Cu/Zn SOD. A normal human stromal cell line was used as control. Osteosarcoma cells were stimulated with TNF alpha, a cytokine previously shown to have antiproliferative activity. The release of Cu/Zn SOD into the supernatant was higher for the HOS and U-2 OS lines when compared to the other cell lines evaluated both in basal condition and after incubation with TNF alpha. Elevated intracellular levels of Cu/Zn SOD were shown except for the HOS and U-2 OS which possess high concentrations of the enzyme at 24 hours declining during the other incubation periods. These concentrations were increased after TNF alpha treatment. The different behaviour of the four cell lines evaluated might be explained by their degree of differentiation.