Association Between Pseudotumor Formation and Patient Factors in Metal-on-Metal Total Hip Arthroplasty Population.

BACKGROUND: Pseudotumor formation from metal-on-metal (MoM) hip implants is associated with implant revision. The relationship between pseudotumor type and patient outcomes is unknown. METHODS: We retrospectively reviewed patients with a MoM total hip arthroplasty and metal artifact reduction sequence magnetic resonance imaging. Pseudotumors were graded using a validated classification system by a fellowship-trained radiologist. Patient demographics, metal ion levels, and implant survival were analyzed. RESULTS: Pseudotumors were present in 49 hips (53%). Thirty-two (65%) pseudotumors were cystic thin walled, 8 (16%) were cystic thick walled, and 9 (18%) were solid masses. Patients with pseudotumors had high offset stems (P = .030) but not higher metal ion levels. Patients with thick-walled cystic or solid masses were more likely to be symptomatic (P = .025) and were at increased risk for revision (P = .004) compared to patients with cystic lesions. CONCLUSION: Pseudotumor formation is present in 53% of patients with a MoM total hip arthroplasty, of which 40% were asymptomatic. Patients with thick-walled cystic and solid lesions were more likely to be symptomatic and undergo revision.

Aseptic Lymphocytic-Dominated Vasculitis-Associated Lesions Scores Do Not Correlate With Metal Ion Levels or Unreadable Synovial Fluid White Blood Cell Counts.

BACKGROUND: Failed metal-on-metal (MoM) bearings are being increasingly encountered with little information to guide evaluation for aseptic lymphocytic-dominated vasculitis-associated lesions (ALVAL). It is often assumed that elevated metal ion levels correlate with the occurrence of ALVAL. Our purpose was to determine the utility of the erythrocyte sedimentation rate, C-reactive protein, synovial white blood cell count, differential (%PMN), and serum metal ion levels in diagnosing ALVAL. METHODS: We identified 80-failed MoM total hip arthroplasties. Tissue was examined under light microscopy and graded on a scale of ALVAL severity. Mean laboratory values were compared between groups and receiver operating curves generated with an area under the curve to determine test performance and optimal cutoffs. RESULTS: ALVAL scores were graded as low in 30 (37.5%), moderate in 39 (49%), and severe in 8 (10%), with 3 being unreadable. No clear cutoff values for erythrocyte sedimentation rate, C-reactive protein, or synovial white blood cell count could be determined to reliably diagnose moderate or severe ALVAL. Furthermore, serum metal levels had no correlation with ALVAL score. The best test to diagnose ALVAL was the synovial fluid monocyte percentage with an optimal cutoff value of 39% and area under the curve of 69% (moderate testing performance). CONCLUSION: The diagnosis of ALVAL remains challenging, with most of the screening tests being unreliable. Although serum metal ion levels are typically elevated in failed MoM bearings, higher levels do not appear to correlate with ALVAL grade. Elevated synovial fluid monocytes may provide diagnostic utility for ALVAL, suggesting a possible delayed-type hypersensitivity reaction.

Metal-on-Metal Hip Replacement: MRI Signal Intensities of Different Body Tissues and Their Relations to Blood Metal Ion Levels.

BACKGROUND: Metal-on-metal total hip prostheses (MoM-THR) have been shown to produce hypersensitivity reactions and fluid collection (pseudotumor) by the hip as well as high blood metal ions levels (BMILs). OBJECTIVES: To evaluate the magnetic resonance imaging (MRI) signal-to-noise ratio (S/N) in selected body tissues around the hip of patients who underwent MoM hip replacement and to correlate to BMILs. METHODS: Sixty-one MRI hip examinations in 54 post-MoM-THR patients (18 males, 36 females, mean age 65 years) were retrospectively evaluated independently by two readers. The mean S/N ratio in a region of interest was calculated for periprosthetic pseudotumor collection (PPC), the bladder, fat, and muscle on axial T1w, FSE-T2w, and short tau inversion recovery (STIR) sequences on the same location. BMILs were retrieved from patient files. RESULTS: PPC was detected in 32 patients (52%) with an average volume of 82.48 mm3. BMIL did not correlate with the presence of PPCs but positively correlated with the PPC's volume. A trend for positive correlation was found between BMILs and S/N levels of STIR images for muscle and bladder as well as for PPC and cobalt levels. A trend for correlation was also seen between BMIL with PPC's T1 w S/N. CONCLUSIONS: Alteration of MRI S/N for different hip tissues showed a tendency for correlation with BMILs, possibly suggesting that metal deposition occurs in the PPC as well as in the surrounding tissues and bladder.

Magnetic Resonance Imaging Predicts Adverse Local Tissue Reaction Histologic Severity in Modular Neck Total Hip Arthroplasty.

BACKGROUND: The association between advanced imaging, serum metal ion levels, and histologic adverse local tissue reaction (ALTR) severity has not been previously reported for Rejuvenate modular neck femoral stems. METHODS: A cohort of 90 patients with 98 Rejuvenate modular neck femoral stems was revised by a single surgeon from July 2011 to December 2014. Before revision, patients underwent multiacquisition variable resonance image combination sequence magnetic resonance imaging (MRI), and serum cobalt and chromium ion levels were measured. Histologic samples from the revision surgery were scored for synovial lining, inflammatory infiltrate, and tissue organization as proposed by Campbell. Regression based on the generalized estimating equations approach was used to assess the univariate association between each MRI, demographic, and metal ion measure and ALTR severity while accounting for the correlation between bilateral hips. Random forest analysis was then used to determine the relative importance of MRI characteristics, demographics, and metal ion levels in predicting ALTR severity. RESULTS: Synovial thickness as measured on MRI was found to be the strongest predictor of ALTR histologic severity in a recalled modular neck femoral stem. CONCLUSION: MRI can accurately describe ALTR in modular femoral neck total hip arthroplasty. MRI characteristics, particularly maximal synovial thickness and synovitis volume, predicted histologic severity. Serum metal ion levels do not correlate with histologic severity in Rejuvenate modular neck total hip arthroplasty.

Do retrieval analysis and blood metal measurements contribute to our understanding of adverse local tissue reactions?

BACKGROUND: Metal-on-metal (MoM) total hip arthroplasties (THAs) and the head-neck and neck-body junctions in modular THA are associated with a variety of local and systemic reactions to their related wear and corrosion products. Although laboratory testing is available, the relationship between laboratory values--including serum metal ion levels--and adverse local tissue reactions (ALTRs) remains controversial and incompletely characterized. QUESTIONS/PURPOSES: (1) What is the range of serum metal levels associated with ALTR in patients who have MoM THAs or corrosion at the head-neck and neck-body junctions in metal-on-polyethylene (or ceramic-on-polyethylene) THAs? (2) How much wear occurs in patients with MoM total hips? (3) Is there evidence of a dose-response relationship between wear and ALTR? METHODS: PubMed and Embase databases were reviewed for English-language studies assessing serum metal levels in the presence of ALTR and papers describing the results of wear measurements from revised MoM implants and ALTR histopathology were systematically reviewed. Reported linear wear data were separated into groups with ALTR and without ALTR as listed in individual papers and graphed to determine whether a dose-response relationship was present between wear and ALTR. Overall, 15 studies including 338 hips with ALTR with corresponding serum metal levels were identified and analyzed. Twelve studies reported the wear depth or volume of MoM components from patients with a variety of local reactions. Two studies investigated corrosion at the head-neck and neck-body junctions in metal-on-polyethylene THA. There was a high level of variability and study heterogeneity, and so data pooling (meta-analysis) could not be performed. RESULTS: Average reported metal concentrations were elevated above established normal values in patients with ALTR (cobalt concentrations ranged from 5 to 40 ppb, and chromium levels ranged from 5 to 54 ppb). Whereas several studies demonstrated that patients with ALTR had higher average linear wear of the bearing surfaces, this finding was not made in all studies that we identified in this systematic review. Because of this high degree of variability, no clear dose-response relationship between wear and ALTR could be established. CONCLUSIONS: Serum metal level analysis and implant retrieval analysis both contribute to the understanding of ALTR. Serum metal levels generally are elevated in the presence of ALTR but should not be used in isolation for clinical decision-making. Many but not all patients with ALTR, including those with pseudotumors, demonstrate high wear, but more data and more systematic descriptions of the histopathology are needed to define the amount of wear that induces adverse reactions.

Fosfomycin-daptomycin and other fosfomycin combinations as alternative therapies in experimental foreign-body infection by methicillin-resistant Staphylococcus aureus.

The efficacy of daptomycin, imipenem, or rifampin with fosfomycin was evaluated and compared with that of daptomycin-rifampin in a tissue cage model infection caused by methicillin-resistant Staphylococcus aureus (MRSA). Strain HUSA 304 was used. The study yielded the following results for MICs (in µg/ml): fosfomycin, 4; daptomycin, 1; imipenem, 0.25; and rifampin, 0.03. The study yielded the following results for minimum bactericidal concentration (MBC) (in µg/ml): fosfomycin, 8; daptomycin, 4; imipenem, 32; and rifampin, 0.5. Daptomycin-rifampin was confirmed as the most effective therapy against MRSA foreign-body infections. Fosfomycin combinations with high doses of daptomycin and rifampin were efficacious alternative therapies in this setting. Fosfomycin-imipenem was relatively ineffective and did not protect against resistance.

Adverse reaction to metal debris after ReCap-M2A-Magnum large-diameter-head metal-on-metal total hip arthroplasty.

BACKGROUND AND PURPOSE: The clinical findings of adverse reaction to metal debris (ARMD) following large-diameter-head metal-on-metal total hip arthroplasty (LDH MoM THA) may include periarticular fluid collections, soft tissue masses, and gluteal muscle necrosis. The ReCap-M2a-Magnum LDH MoM THA was the most commonly used hip device at our institution from 2005 to 2012. We assessed the prevalence of and risk factors for ARMD with this device. METHODS: 74 patients (80 hips) had a ReCap-M2a-Magnum LDH MoM THA during the period August 2005 to December 2006. These patients were studied with hip MRI, serum chromium and cobalt ion measurements, the Oxford hip score questionnaire, and by clinical examination. The prevalence of ARMD was recorded and risk factors for ARMD were assessed using logistic regression models. The mean follow-up time was 6.0 (5.5-6.7) years. RESULTS: A revision operation due to ARMD was needed by 3 of 74 patients (3 of 80 hips). 8 additional patients (8 hips) had definite ARMD, but revision was not performed. 29 patients (32 hips) were considered to have a probable or possible ARMD. Altogether, 43 of 80 hips had a definite, probable, or possible ARMD and 34 patients (37 hips) were considered not to have ARMD. In 46 of 78 hips, MRI revealed a soft tissue mass or a collection of fluid (of any size). The symptoms clicking in the hip, local hip swelling, and a feeling of subluxation were associated with ARMD. INTERPRETATION: ARMD is common after ReCap-M2a-Magnum total hip arthroplasty, and we discourage the use of this device. Asymptomatic patients with a small fluid collection on MRI may not need instant revision surgery but must be followed up closely.

Inflammatory response to orthopedic biomaterials after total hip replacement.

BACKGROUND: The aim of the present study was to investigate early inflammatory response in the first 3 days after the implantation of hip prostheses, and to compare the early inflammation responses associated with the use of different combinations of bearing materials. METHODS: 34 patients were enrolled, all of whom underwent unilateral total hip replacement and had identical hip prostheses, except for the bearing materials. These consisted of polyethylene on alumina (n = 8), polyethylene on CoCr (n = 11), or alumina on alumina (n = 15). Blood samples were collected preoperatively in the morning of the day of surgery, and at 6 h, 1 day, 2 days, and 3 days postoperatively. CK, CRP, and IL-6 in peripheral blood were measured. Pain score was obtained at 2 days after surgery. RESULTS: There were no significant differences in the pre- and postoperative background variables among the groups. Pain scores of different groups were not significantly different either (P > 0.05). There were also no significant differences in the levels of CK, CRP, and IL-6 when patients with the three combinations of bearing materials were compared. CONCLUSIONS: We concluded that varying the bearing materials used in the hip prosthesis did not influence the early inflammatory response after prosthesis implantation.

Does a bilateral polypropylene mesh alter the duct deferens morphology, testicular size and testosterone levels? Experimental study in rats.

PURPOSE: To evaluate the effect of a PP mesh on duct deferens morphology, testicular size and testosterone levels. METHODS: Forty adult male rats were distributed into groups: 1) no surgery; 2) inguinotomy; 3) mesh placed on the duct deferens; and 4) mesh placed on the spermatic funiculus. After 90 postoperative days, the inguinal region was resected, and blood samples were collected for the measurement of serum testosterone (pg/dl). The ducts deferens were sectioned in three axial sections according to the relationship with the mesh - cranial, medial and caudal. The wall thickness and duct deferens lumen area were measured. RESULTS: The morphology of the duct deferens was preserved in all groups. The mesh placement did not alter this morphology in any of the analyzed segments. Surgery, with or without mesh placement, did not alter the morphology, wall thickness or lumen area (p>0.05). In all operated groups, serum testosterone levels were similar (p>0.05) but there was a decrease in testicle size (p<0.05). CONCLUSION: Surgery, with or without mesh placement, did not alter the morphology of the duct deferens and, although this treatment resulted in testicular size reduction, it did not affect serum testosterone levels.

Coated prostheses are associated with prolonged inflammation in aortic surgery: a cost analysis.

This prospective study was conducted to compare inflammatory responses between patients receiving coated and uncoated vascular prostheses, and to examine their effect on length of stay and cost of patients undergoing abdominal aortic aneurysmectomy. Patients undergoing elective vascular reconstruction of an abdominal aortic aneurysm were assigned randomly to coated-graft or uncoated-graft groups (n = 20, for each group). Interleukin (IL)-6, granulocyte elastase, white blood cell count, C-reactive protein (CRP), and body temperature (BT) were prospectively recorded preoperatively and on postoperative days (PODs) 1, 3, 7, and 14. In-hospital stay and hospitalized costs were also analyzed. IL-6 and CRP concentrations in the coated-graft group were higher than those in the uncoated-graft group (P = 0.01 and 0.05). BT was more frequently elevated >37 degrees C at POD 14 in the coated-graft group than in the uncoated-graft group (P =0.03). Discharge was delayed, and overall hospitalization cost was higher in the coated-graft group than in the uncoated group (17.6 vs. 13.5 days, and 2 010 000 vs. 1 780 000 yen, P = 0.006 and P = 0.002, respectively). Coated vascular prosthesis demonstrated more profound inflammatory reaction than noncoated prosthesis, postoperatively.

Systematic Screening of Adverse Reactions to Metal Debris after Recap-M2A-Magnum Metal-on-Metal Total Hip Arthroplasty.

BACKGROUND AND AIMS: An adverse reaction to metal debris is a known complication after large diameter head metal-on-metal total hip arthroplasty. However, the failure rate varies depending on the implant design. Therefore, we investigated the prevalence of adverse reaction to metal debris, as well as the symptoms and risk factors after undergoing a ReCap-M2a-Magnum large diameter head metal-on-metal total hip arthroplasty. MATERIALS AND METHODS: Between 2005 and 2012, 1188 patients (1329 hips) underwent ReCap-M2a-Magnum total hip arthroplasty at our institution. Systematic screening for adverse reaction to metal debris was arranged using the Oxford Hip Score questionnaire, hip and pelvic radiographs, and assessments of the serum chromium and cobalt ion levels. Clinical evaluation and magnetic resonance imaging were performed for the symptomatic patients, as well as those with either chromium or cobalt ion levels ⩾5 µg/L. The prevalence of adverse reaction to metal debris after ReCap-M2a-Magnum total hip arthroplasty was assessed, and the risk factors for adverse reaction to metal debris were evaluated using logistic regression. The mean follow-up time was 5.2 (0.003-9.1) years. This study was an extension of a previous study conducted at our institution with 80 patients. RESULTS: In total, 33 patients (33 hips, 2.5% of all hips) required a revision operation due to adverse reaction to metal debris. Moreover, 157 hips exhibited definitive adverse reaction to metal debris, but a revision operation was not performed (157 of 1329 hips, 11.8% of all hips). Overall, 190 out of 1329 (14.3%) hips had definitive adverse reaction to metal debris. Pain, subluxation sensation, clicking, swelling, a small head size, and a fair/poor Oxford Hip Score were associated with definitive adverse reaction to metal debris. CONCLUSION: We found a high prevalence of adverse reaction to metal debris in the ReCap-M2a-Magnum total hip arthroplasty patients in this study; however, most of the patients did not require revision operations.

Monocyte subsets in blood correlate with obesity related response of macrophages to biomaterials in vitro.

Macrophages play a key role in the foreign body response. In this study it was investigated whether obesity affects the acute response of macrophages to biomaterials in vitro and whether this response is associated with biomarkers in blood. CD14 + monocytes were isolated from blood from obese and age and gender matched lean persons. Monocyte subsets were determined based on CD14 and CD16 on their surface. C-reactive protein (CRP) was measured in peripheral blood. The response of monocyte-derived macrophages to polypropylene (PP), polylactic acid (PLA), polyethylene terephthalate (PET) monofilament, and PET-multifilament (mPET) in culture was based on cytokine production. More IL-6 (for PET), less CCL18 (all materials) and IL-1ra (for PLA) was produced by macrophages from obese patients than lean subjects. Body mass index, serum CRP and to a lesser extend percentages of monocyte subtypes correlated with IL-6, TNFα, CCL18, and IL-1ra production. Taken together, monocyte-derived macrophages of obese patients respond more pro-inflammatory and less anti-inflammatory to biomaterials than macrophages from lean subjects, depending on the material. These results are a step towards personalized medicine for the development of a model or even a blood test to decide which biomaterial might be suitable for each patient.

Inflammatory response to peritoneal implantation of alginate-poly-L-lysine microcapsules.

A thorough understanding of the mechanisms involved in the host reaction to alginate-poly-L-lysine microcapsules (HRM) is important to design methods for the evaluation, selection, and development of biocompatible biomaterials and microcapsules or treatments to control this reaction. The objective of this study was to identify those immune cells and cytokines involved in the pathogenesis of the HRM. The total and differential cell counts were evaluated, and the mRNA expression of TNF-alpha, IL-1beta, IL-6 and TGF-beta1 was measured in peritoneal washings at 3, 17, 48, 96 and 168 h after saline or microcapsule injections. Neutrophil number and IL-1beta and IL-6 m-RNA expression presented an early transient increase, with no differences between saline and microcapsule injections, suggesting a reaction to the procedure. Macrophages, lymphocytes and TNF-alpha were significantly more activated over a longer period of time, after microcapsule implantation than saline injection. They are likely involved in transforming the reaction into a chronic inflammatory process. TGF-beta1 and IL-1beta presented a late (day 7) significant increase after microcapsule but not saline injections. They are likely involved in transforming the reaction into a fibrogenic process. These results suggest that macrophages, lymphocytes, TNF-alpha, IL-1beta and TGF-beta1 play a role in the pathogenesis of the HRM.

Effect of dietary supplementation with vitamin E and stocking density on macrophage recruitment and giant cell formation in the teleost fish, Piaractus mesopotamicus.

The effect of dietary supplementation with 0, 100 and 450 mg of vitamin E (DL-alpha tocopheryl acetate)/kg of a dry diet on the kinetics of macrophage recruitment and giant cell formation in the pacu, maintained at different stocking densities (5 kg/m(3) and 20 kg/m(3)), was investigated by insertion of round glass coverslips into the subcutaneous connective tissue. After a feeding period of 18 weeks, the coverslips were implanted and later removed for examination at 2, 7 and 15 days post-implantation. Fish fed diets supplemented with 450 mg of vitamin E showed an increase (P<0.05) in the accumulation of macrophages, foreign body giant cells and Langhans type cells. The kinetics of macrophage recruitment and giant cell formation on the glass coverslips appeared to be strongly influenced by vitamin E supplementation, since fish fed a basal diet and held at high stocking densities showed low numbers of adhering cells on the coverslips, and high concentrations of plasma corticosteroids. On the other hand, fish given a diet supplemented with 450 mg of vitamin E did not show a similar difference in plasma cortisol concentrations related to stocking density. The effect of cortisol concentrations on carbohydrate metabolism, analysed by assessment of plasma glycaemia, was not clear. Blood glucose concentrations did not vary substantially with the different treatments examined. These results suggest that vitamin E may contribute to the efficiency of the fish's inflammatory response by increasing macrophage recruitment and giant cell formation in the foreign body granulomatous reaction. Vitamin E appeared to act on the stress response of pacus by preventing a stress-related immunosuppression.

Does a bilateral polypropylene mesh alter the duct deferens morphology, testicular size and testosterone levels? Experimental study in rats

Abstract Purpose To evaluate the effect of a PP mesh on duct deferens morphology, testicular size and testosterone levels. Methods Forty adult male rats were distributed into groups: 1) no surgery; 2) inguinotomy; 3) mesh placed on the duct deferens; and 4) mesh placed on the spermatic funiculus. After 90 postoperative days, the inguinal region was resected, and blood samples were collected for the measurement of serum testosterone (pg/dl). The ducts deferens were sectioned in three axial sections according to the relationship with the mesh — cranial, medial and caudal. The wall thickness and duct deferens lumen area were measured. Results The morphology of the duct deferens was preserved in all groups. The mesh placement did not alter this morphology in any of the analyzed segments. Surgery, with or without mesh placement, did not alter the morphology, wall thickness or lumen area (p>0.05). In all operated groups, serum testosterone levels were similar (p>0.05) but there was a decrease in testicle size (p<0.05). Conclusion Surgery, with or without mesh placement, did not alter the morphology of the duct deferens and, although this treatment resulted in testicular size reduction, it did not affect serum testosterone levels.

Systemic inflammatory cytokine analysis to monitor biomaterial augmented tissue healing.

PURPOSE: Hernias can be repaired by reinforcement of damaged fascia using biomaterials to provide stabilisation. Repair materials are usually porous, through which cells infiltrate, proliferate and secrete ECM. Their efficacy relies on good tissue integration and resolution of host defence mechanisms. Therefore, understanding the dynamics by which biomaterials interact with tissue will provide knowledge to advance prosthesis design. Furthermore, determining host response in real time would provide significant advantage both clinically and scientifically over the current terminal process of histology. METHODS: 3 materials comprising synthetic and composite (synthetic materials hybridised with a resorbable biologic component) meshes were implanted into a rat full-thickness abdominal wall excision model. Their efficacy was evaluated using histopathology whilst also monitoring systemic concentrations of cytokines associated with inflammation and wound healing to predict material outcome over 12 weeks. RESULTS: The noncomposite material (polyester) and Material B (polypropylene mesh with oligocaprone film and polydioxanone glue) stimulated the largest degree of adhesion from the 3 materials tested, although after 28 days adhesions were stronger to Material B. Histologically, all 3 materials integrated well with abdominal musculature and infiltrated completely with cells. CONCLUSIONS: Analysis of systemic inflammation biomarkers confirmed inflammation elicited by surgeries and meshes irrespective of their composition. However, at an early postoperative endpoint (i.e., 1 week), some biomarkers, namely, IL-18 and RANTES, appeared to discriminate the noncomposite mesh from the composite materials, although in this study all materials successfully repaired the defects without recurrence or external indicators of postoperative chronic pain.

Immunologic sensitization in recipients of left ventricular assist devices.

OBJECTIVE: Left ventricular assist device implantation is associated with an increased risk of development of circulating anti-HLA class I and II antibodies (sensitization). We investigated the impact of sensitization on posttransplantation outcomes in 105 consecutive left ventricular assist device recipients. METHODS: Five hundred twenty-one consecutive adult cardiac allograft recipients between 1992 and 1999 were retrospectively studied. Of these, 105 were supported with a left ventricular assist device. Pretransplantation and posttransplantation antibody production, time to transplantation after listing, rejection, freedom from transplant coronary artery disease, and survival were evaluated by Kaplan-Meier analysis. Among sensitized left ventricular assist device recipients, 26 were treated with a pretransplantation immunomodulatory regimen consisting of intravenous immunoglobulin and cyclophosphamide. RESULTS: There were no significant differences between left ventricular assist device recipients and nonbridged recipients with respect to pretransplantation demographic characteristics and ABO and HLA matching. Among left ventricular assist device recipients, 66% (69/105) were sensitized before transplantation; in contrast, only 6% (24/399) of nonbridged recipients were sensitized (P <.001). Sensitized untreated left ventricular assist device recipients had both a prolongation of waiting time to transplantation and an increased risk of acute rejection. Pretransplantation immunomodulatory therapy reduced both the increased waiting time and the increased risk of acute rejection. However, sensitization or the use of immunomodulatory therapy in left ventricular assist device-bridged recipients did not influence posttransplantation survival relative to nonbridged recipients. CONCLUSIONS: Left ventricular assist device recipients have survival outcomes similar to those of nonbridged recipients after cardiac transplantation, despite their significantly higher immunologic risk. The reduced rate of transplantation and the increased incidence of rejection observed in sensitized left ventricular assist device recipients are prevented by immunomodulatory therapy. Sensitization will remain an important issue with increased use of left ventricular assist devices, and improved understanding of this is essential to achieve better outcomes in the management of patients with end-stage heart failure.

Tension-free hernia repair is associated with an increase in inflammatory response markers against the mesh.

BACKGROUND: The purpose of this study was to evaluate the involvement of inflammatory mediators in patients undergoing Lichtenstein tension-free hernioplasty (LH) using polypropylene prosthetic materials or conventional Bassini hernia repair (BH). METHODS: Thirty patients male with unilateral inguinal hernia without complications or recurrence were included in this study. Randomly, patients underwent LH or BH. Peripheral venous bloods samples were collected 24 hours prior to surgery and then 6, 24, 48 and 168 hours postoperatively. RESULTS: We present evidences that LH patients showed a higher increased serum level of fibrinogen, C-reactive protein, alpha-1-antitrypsin, and interleukin-6 than BH patients. Postoperative visual analogue scales for pain were reduced on mobilization for patients undergoing LH compared with BH. Neutrophils were significantly increased only in LH compared with baseline. Ceruloplasmin, transferrin, and albumin levels were unmodified after BH or LH. CONCLUSIONS: In conclusion our data show that although LH induces less pain and more rapid postoperative recovery, it is associated with an higher inflammatory response compared with BH, likely due to polypropylene mesh.

Acute inflammation effects on in vivo granulopoiesis: comparative studies in healthy and leukaemic mice.

Mice undergoing an inflammatory reaction, induced by subcutaneous implantation of copper rods, elaborate two kinds of humoral stimulatory factors: the diffusible granulopoietic stimulator (DGS) that enhances diffusion chamber (DC) granulopoiesis, and the serum colony stimulating factor (CSF) that stimulates in vitro granulocyte-monocyte colony growth. We demonstrate here that mice suffering from acute myeloid leukaemia (AML) are unable to augment the production of these humoral stimulatory factors when acute inflammation is induced. Moreover, our results show that increased levels of normal humoral stimulatory factors (DGS and CSF) do not influence the proliferation and/or the differentiation of leukaemic cells implanted in DC.

Postoperative inflammatory reactions to sealed Dracon prostheses: a comparison of Gelseal and Hemashield.

OBJECTIVE: The purpose of this study was to assess and compare inflammatory reactions to two types of sealed vascular prostheses used in the repair of abdominal aortic aneurysm. EXPERIMENTAL DESIGN: Randomized prospective study with a follow-up period of 21 days. SETTING: University hospital study. PATIENTS: Sixty patients admitted for elective abdominal aortic aneurysm repair. INTERVENTION: Each patient underwent repair of abdominal aortic aneurysm with either a gelatin-sealed knitted Dacron prosthesis (Gelseal, Vascutek, n = 30) or a collagen-sealed woven Dacron prosthesis (Hemashield, Meadox Medicals, n = 30). MEASURES: As indicators of the presence of inflammation, the peripheral blood cell count, platelet count, and plasma C-reactive protein (CRP) concentration were determined in each patient on postoperative days (PODs) 1, 7, 14 and 21. Body temperature was measured every 8 hours. RESULTS: Patients in both groups revealed a low-grade fever and leukocytosis during the first 7 PODs. Significantly higher leukocyte counts were demonstrated in the Gelseal group on PODs 7 and 14. However, no difference in the leukocyte count, CRP concentration, or body temperature existed between the two groups on POD 21. Biphasis changes in the platelet count were observed in both groups. No complications were encountered. CONCLUSION: The Gelseal prosthesis was associated with higher inflammatory response during the second week following implantation, but this difference had resolved by POD 21. This finding may reflect an inflammatory reaction against impregnated gelatin.