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OBJECTIVE: We previously reported significant variations in oxidation status and molecular length among sources and lots of human serum albumin (HSA) commercial preparations intended for clinical use. In this report, we investigated what effect the presence of HSA products have on the immune response in vitro. DESIGN: Laboratory study. SETTING: Trauma research basic science laboratory. SUBJECTS: Activated human peripheral blood mononuclear cells. INTERVENTIONS: Six commercial HSA preparations were tested for their effect on cytokine release from activated human peripheral blood mononuclear cells (PBMCs) and T-lymphocytes. Mass spectrometry analysis of aspartyl-alanyl diketopiperazine (DA-DKP) content of HSA and percentage of HSA having lost its amino terminal dipeptide aspartyl alanyl (HSA-DA) were correlated. MEASUREMENTS AND MAIN RESULTS: Human PBMCs were cultured in the presence of six commercial HSA preparations and activated via the T-cell receptor complex. A cloned T-lymphocyte cell line, activated with specific antigen, was also cultured with both synthetic DA-DKP and small molecular weight extracts from the commercial HSA tested. Supernatants were quantified by enzyme-linked immunosorbent assay for interferon-gamma and tumor necrosis factor-alpha content. DA-DKP was extracted from HSA by centrifugal filters and quantified by anion exchange liquid chromatography coupled to negative electrospray ionization mass spectrometry. HSA species were determined by reverse phase liquid chromatography coupled to positive electrospray ionization, time of flight mass spectrometry. All HSA preparations significantly inhibited the in vitro production of interferon-gamma and tumor necrosis factor-alpha by activated PBMCs. DA-DKP was detected in all HSA sources at concentrations ranging between 42.0 and 79.6 muM. A synthetic form of DA-DKP possessed similar immunosuppressive qualities in a dose-dependent manner on T lymphocytes. CONCLUSIONS: DA-DKP was present in significant concentrations in all HSA sources tested and was partially responsible for the immunosuppressive effects of HSA on activated PBMCs and T-lymphocytes in vitro. In view of these findings, administering HSA to immunocompromised critically ill patients might be reevaluated. [ABSTRACT FROM AUTHOR]

Objectives: Surgical simulation is an increasingly important method to facilitate the acquiring of surgical skills. Simulation can be helpful in developing hip fracture fixation skills because it is a common procedure for which performance can be objectively assessed [ie, the tip-apex distance (TAD)]. The procedure requires fluoroscopic guidance to drill a wire along an osseous trajectory to a precise position within bone. The objective of this study was to assess the construct validity for a novel radiation-free simulator designed to teach wire navigation skills in hip fracture fixation., Methods: Novices (n = 30) with limited to no surgical experience in hip fracture fixation and experienced surgeons (n = 10) participated. Participants drilled a guide wire in the center-center position of a synthetic femoral head in a hip fracture simulator, using electromagnetic sensors to track the guide-wire position. Sensor data were gathered to generate fluoroscopic-like images of the hip and guide wire. Simulator performance of novice and experienced participants was compared to measure construct validity., Results: The simulator was able to discriminate the accuracy in guide-wire position between novices and experienced surgeons. Experienced surgeons achieved a more accurate TAD than novices (13 vs. 23 mm, respectively, P = 0.009). The magnitude of improvement on successive simulator attempts was dependent on the level of expertise; TAD improved significantly in the novice group, whereas it was unchanged in the experienced group., Conclusions: This hybrid reality, radiation-free hip fracture simulator, which combines real-world objects with computer-generated imagery, demonstrates construct validity by distinguishing the performance of novices and experienced surgeons. There is a differential effect depending on the level of experience, and it could be used as an effective training tool in novice surgeons., Competing Interests: The authors declare that they have no conflict of interest.

Background: The pyruvate dehydrogenase complex (PDC) catalyzes the conversion of pyruvate to acetyl CoA, effectively controlling the entrance of glycolysis products into aerobic metabolism. Because hyperlactatemia is one of the hallmarks of sepsis, we hyphothesized that gram-positive and negative bacterial toxin treatment will interfere with mRNA levels of regulatory enzymes of the PDC and overall enzyme activity in hepatocytes., Methods: HEP G2 hepatocarcinoma cells were incubated for 24 hours in the presence of lipopolysaccaride (LPS) or lipoteichoic acid. Total RNA was then isolated and message RNA levels for both pyruvate dehydrogense kinase 4 and phosphatase 2 were determined by RTPCR. Amplified DNA fragments were visualized by ethidium bromide in agarose gels and densitometry of the bands was performed. Data were then normalized to the housekeeping gene, GAPDH. Enzyme activity was then determined by capturing intact PDC on nitrocellulose membranes then determining PDC-dependent production of NADH., Results: LPS treatment led to a time dependent increase in PDK4 message while decreasing PDP2 levels. Enzyme activity, in these cells, also significantly decreased 24 hours after exposure to LPS. Cells cultured in the presence of lipoteichoic acid and insulin exhibited differing message ratios and activity levels when evaluated at 4 hours, but at 24 hours shifted to mimic those observed in LPS treated cells., Conclusion: This data may indicate that exposure to bacterial cell wall components and insulin could create cellular environments that result in a build-up of lactate.

Background: The cytotoxic effects of antiseptics on pivotal cell types of the healing process have been well documented. The purpose of our investigation was to explore the ability of subcytotoxic levels of antiseptics to interfere with fibroblast function., Methods: Cell proliferation assays were performed by culturing fibroblasts in the presence of commonly used antiseptics. Migration was evaluated using scratch assays in which monolayers were "wounded" and cellular movement was monitored by digital photography. Matrix metalloproteinase (MMP) release was analyzed by zymography., Results: H2O2 and povidone-iodine reduced both migration and proliferation of fibroblasts in a dose-dependent fashion. Treatment with silver-containing antiseptics and chlorhexidine exhibited reductions in proliferation at high concentrations, but enhanced growth at lower doses. Silver-containing compounds and chlorhexidine also proved to be the least detrimental to migration in these assays. metalloproteinase release from the cells was differently affected depending on the dosage and class of antiseptic applied., Conclusions: When debridement of the wound bed is not sufficient to reduce bacterial loads, the application of broad-spectrum antiseptics maybe indicated. Our data would suggest that H2O2 and iodine are poor choices, potentially retarding the contribution of fibroblasts to the healing process. Silver sulfadiazine and chlorhexidine, at levels still proven to be bactericidal, had fewer detrimental effects on fibroblast activity in these assays. The silver-containing antiseptics may even increase the proliferative potential of these cells in culture.

Endogenous copper can play an important role in postischemic reperfusion injury, a condition associated with endothelial cell activation and increased interleukin 8 (IL-8) production. Excessive endothelial IL-8 secreted during trauma, major surgery, and sepsis may contribute to the development of systemic inflammatory response syndrome (SIRS), adult respiratory distress syndrome (ARDS), and multiple organ failure (MOF). No previous reports have indicated that copper has a direct role in stimulating human endothelial IL-8 secretion. Increased IL-8 in the culture medium of human umbilical vein (HUVEC), lung microvascular, and iliac artery endothelial cells was observed 24 h after the addition of 10 to 50 microM CuCl2 (cupric ions). HUVEC IL-8 induction by copper was higher than by 50 pg/mL tumor necrosis factor-alpha, whereas 50 pg/mL IL-1beta and 1 ng/mL platelet-activating factor did not stimulate IL-8 production or release. HUVEC IL-8 mRNA increased 3 h after CuCl2 stimulation and remained elevated after 24 h, implying sustained transcriptional activation. Copper did not stimulate HUVECs to secrete other cytokines. Cu(II) appeared to be the primary copper ion responsible for the observed increase in IL-8 because a specific high-affinity Cu(II)-binding peptide, d-Asp-d-Ala-d-His-d-Lys (d-DAHK), completely abolished this effect in a dose-dependent manner. These results suggest that Cu(II) may induce endothelial IL-8 by a mechanism independent of known Cu(I) generation of reactive oxygen species. Furthermore, in vivo studies are warranted to determine if copper is involved in the pathogenesis of systemic inflammation and if Cu(II) chelation can reduce this IL-8-induced endothelial inflammatory response.

The pathological findings in a retrospective review of 100 consecutive intracranial stereotactic biopsies are presented. Definite diagnosis could be established in the majority (89) of cases and included 85 neoplasms (69 primary cerebral tumors, 10 non-Hodgkin's lymphomas and 6 metastases) and 4 non-neoplastic processes. In the remaining 11 samples the findings were non-diagnostic; 2 consisted of normal glial tissue, while the remainder variously showed changes of necrosis, hematoma, histiocytic reaction or astrocytic proliferations of uncertain nature. Verification of the stereotactic diagnosis by examination of lesional tissue obtained at subsequent craniotomy or postmortem was possible in 7 of 10 cases. Two broad categories of diagnostic difficulty were identified in interpreting stereotactic biopsies: (1) accurate tumor typing and grading, and (2) the distinction between reactive and neoplastic astrocytic proliferations. Two essential components in the diagnostic process are: (1) careful correlation with the clinical and radiological findings; and (2) use of intraoperative smear and/or frozen section preparations to confirm specimen adequacy. By adhering to these principles accurate intraoperative diagnosis can usually be established, particularly for high grade astrocytoma, lymphoma and metastasis. Tumor typing is aided by the use of immunohistochemistry and ultrastructural examination and the examination of serial sections is of value in grading.

Neuronal differentiation was demonstrated by light microscopy, immunohistochemistry and electron microscopy in the cerebral neoplasms of one adolescent and five adult patients. The tumours exhibited a wide spectrum of cellular differentiation from low to high grade malignancy which seems to correlate well with their biological behaviour. The natural history of these 6 cerebral neuroblastomas is rather long compared to that of other malignant primary cerebral neoplasms of adulthood; however, 2 patients died, one survived about 5 yr after initial symptoms whilst an untreated patient survived more than 12 yr. It is suggested that morphological grading along the lines of Kernohan's system may be useful in determining the prognosis and postoperative management of patients with cerebral neuroblastomas.