Estimation of In Vivo Reticuloendothelial System Phagocytic Activity in Rats by Direct Blood Clearance Techniques and Nuclear Scintigraphy

There has been considerable interest in the examination off reticuloendothelial system phagocytic blockade. In this study, the kinetics of phospholipid liposome‐mediated and intraperitoneal silica‐mediated phagocytic blockade were examined using five methods off analysis off in vivo 99mTc‐labeled albumin clearance and reticuloendothelial cell uptake. Two direct blood sampling techniques revealed significant impairment in 99mTc‐labeled albumin clearance after treatment with silica (P < 0.05), while liposome treatment was not associated with such impairment. A method utilizing nuclear scintigraphy for the determination of blood clearance was incapable of detecting silica‐mediated blockade but demonstrated significant impairment by liposomes at 2 hr (P < 0.001), 6 hr (P < 0.05), and 24 hr (P < 0.001). Gamma camera imaging methods for determination of hepatic uptake demonstrated significant (P < 0.05) and reversible impairment of 99mTc‐labeled albumin uptake by liposomes. The most promising of these techniques utilizes deconvolutional analysis off liver region of interest time–activity curves to correct for continuously changing blood concentrations of tracer and for intracellular tracer processing and catabolism. Measurements of reticuloendothelial system phagocytic activity should include methods that take into account the observed discrepancies between blood clearance determinations and reticuloendothelial cell uptake.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141016/1/jlb0060.pd

The effect of glycosidases on the survival of rat erythrocytes in circulation

Enzymic removal of sialyl groups from mammalian erythrocytes resulted in their rapid sequestration from circulation subsequent to autologous transfusion. It has been demonstrated by many investigators that the terminal [beta]--galactosyl group, exposed on red blood cell by in vitro desialosylation, is recognized by an autoimmune anti-galactosyl IgG and/or by a lectin-like receptor on monocytes and macrophages. It is demonstrated herein that the disaccharide structure [beta]--Galp-(1--&gt;3)--GalpNAc (a) is masked in normal rat RBC, but exposed in asialo-RBC; (b) could be detected with fluorescently-labeled peanut agglutinin; (c) could be released from the asialo-RBC with an endo-N-acetyl-[alpha]--galactosaminidase; and (d) upon its removal by treatment with the endo-N-acetyl-[alpha]--galactosaminidase, enhances the survival of the asialo-RBC in circulation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27216/1/0000220.pd

Flow cytometric analysis of human erythrocytes: I. Probed with lectins and immunoglobulins

A recent review (Aminoff, 1988) summarized the evidence for and against our hypothesis for the role of glycophorin in the senescence and clearance of mammalian red blood cells (RBC) from circulation. This hypothesis postulates the loss of sialic acid from RBC surface in two forms: (a) as vesicles containing the sialoglycoprotein glycophorin, and (b) as free sialic acid residues from glycophorin molecules remaining on cell surface. In this report we demonstrate the applicability of flow cytometric procedures to explore, at the cellular level, time-dependent changes on RBC surface with change in cell size, and with in vivo age. The RBC are probed with fluorescein isothiocyanate (FITC) labelled lectins and goat anti-human-IgG and -IgM. The relative intensity of fluorescence is correlated to the change in RBC size as measured by forward lightscatter. Reactivity of RBC with FITC-labelled wheat germ agglutinin can be inhibited with either 0.2M N-acetylglucosamine or by removal of sialic acid residues with neuraminidase. The properties of the smallest RBC correspond to those of the oldest RBC in their: (a) decreased reactivity with FITC-labelled lectins that recognize sialic acid residues, wheat germ and Limax flavus agglutinins, and (b) increased reactivity with FITC-labelled goat anti-human-IgG and -IgM. These results are compatible with our glycophorin hypothesis. Moreover, they suggest that the initial loss of sialic acid as glycophorin containing vesicles is gradual, while the subsequent step involving the loss of sialic acid residues is rapid and exposes multiple disaccharide galactose [beta](1-3)N-acetylgalacosaminyl residues. These unmasked disaccharide sites are recognized by autoimmune IgG, IgM, and lectin-like receptors on macrophages resulting in the clearance of senescent RBC from circulation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29600/1/0000689.pd

Evidence-based Practices for Thromboembolism Prevention: Summary of the ASPS Venous Thromboembolism Task Force Report

In July of 2011, the American Society of Plastic Surgeons Executive Committee approved the Venous Thromboembolism Task Force Report. The report includes a summary of the scientific literature relevant to venous thromboembolism and plastic surgery along with five evidence-based recommendations. The recommendations are divided into two sections: risk stratification and prevention. The risk stratification recommendations are based on the 2005 Caprini Risk Assessment Module, which has been validated in the scientific literature as an effective tool for risk-stratifying plastic and reconstructive surgery patients based on individual risk factors for 60-day venous thromboembolism. The three prophylaxis recommendations are dependent on an individual patient\u27s 2005 Caprini Risk Assessment Module score

A Multi-Institutional Analysis of Insurance Status as a Predictor of Morbidity Following Breast Reconstruction.

BACKGROUND: Although recent literature suggests that patients with Medicaid and Medicare are more likely than those with private insurance to experience complications following a variety of procedures, there has been limited evaluation of insurance-based disparities in reconstructive surgery outcomes. Using a large, multi-institutional database, we sought to evaluate the potential impact of insurance status on complications following breast reconstruction. METHODS: We identified all breast reconstructive cases in the 2008 to 2011 Tracking Operations and Outcomes for Plastic Surgeons clinical registry. Propensity scores were calculated for each case, and insurance cohorts were matched with regard to demographic and clinical characteristics. Outcomes of interest included 15 medical and 13 surgical complications. RESULTS: Propensity-score matching yielded 493 matched patients for evaluation of Medicaid and 670 matched patients for evaluation of Medicare. Overall complication rates did not significantly differ between patients with Medicaid or Medicare and those with private insurance (P = 0.167 and P = 0.861, respectively). Risk-adjusted multivariate regressions corroborated this finding, demonstrating that Medicaid and Medicare insurance status does not independently predict surgical site infection, seroma, hematoma, explantation, or wound dehiscence (all P \u3e 0.05). Medicaid insurance status significantly predicted flap failure (odds ratio = 3.315, P = 0.027). CONCLUSIONS: This study is the first to investigate the differential effects of payer status on outcomes following breast reconstruction. Our results suggest that Medicaid and Medicare insurance status does not independently predict increased overall complication rates following breast reconstruction. This finding underscores the commitment of the plastic surgery community to providing consistent care for patients, irrespective of insurance status

Individualized Risk of Surgical Complications: An Application of the Breast Reconstruction Risk Assessment Score.

BACKGROUND: Risk discussion is a central tenet of the dialogue between surgeon and patient. Risk calculators have recently offered a new way to integrate evidence-based practice into the discussion of individualized patient risk and expectation management. Focusing on the comprehensive Tracking Operations and Outcomes for Plastic Surgeons (TOPS) database, we endeavored to add plastic surgical outcomes to the previously developed Breast Reconstruction Risk Assessment (BRA) score. METHODS: The TOPS database from 2008 to 2011 was queried for patients undergoing breast reconstruction. Regression models were constructed for the following complications: seroma, dehiscence, surgical site infection (SSI), explantation, flap failure, reoperation, and overall complications. RESULTS: Of 11,992 cases, 4439 met inclusion criteria. Overall complication rate was 15.9%, with rates of 3.4% for seroma, 4.0% for SSI, 6.1% for dehiscence, 3.7% for explantation, 7.0% for flap loss, and 6.4% for reoperation. Individualized risk models were developed with acceptable goodness of fit, accuracy, and internal validity. Distribution of overall complication risk was broad and asymmetric, meaning that the average risk was often a poor estimate of the risk for any given patient. These models were added to the previously developed open-access version of the risk calculator, available at http://www.BRAscore.org. CONCLUSIONS: Population-based measures of risk may not accurately reflect risk for many individual patients. In this era of increasing emphasis on evidence-based medicine, we have developed a breast reconstruction risk assessment calculator from the robust TOPS database. The BRA Score tool can aid in individualizing-and quantifying-risk to better inform surgical decision making and better manage patient expectations

Is There a Safe Lipoaspirate Volume? A Risk Assessment Model of Liposuction Volume as a Function of Body Mass Index.

BACKGROUND: No concrete data exist to support a specific volume at which liposuction becomes unsafe; surgeons rely on their own estimates, professional organization advisories, or institutional or government-imposed restrictions. This study represents the first attempt to quantify the comprehensive risk associated with varying liposuction volumes and its interaction with body mass index. METHODS: Suction-assisted lipectomies were identified from the Tracking Operations and Outcomes for Plastic Surgeons database. Multivariate regression models incorporating the interaction between liposuction volume and body mass index were used to assess the influence of liposuction volume on complications and to develop a tool that returns a single adjusted odds ratio for any combination of body mass index and liposuction volume. Recursive partitioning was used to determine whether exceeding a threshold in liposuction volume per body mass index unit significantly increased complications. RESULTS: Sixty-nine of 4534 patients (1.5 percent) meeting inclusion criteria experienced a postoperative complication. Liposuction volume and body mass index were significant independent risk factors for complications. With progressively higher volumes, increasing body mass index reduced risk (OR, 0.99; 95 percent CI, 0.98 to 0.99; p = 0.007). Liposuction volumes in excess of 100 ml per unit of body mass index were an independent predictor of complications (OR, 4.58; 95 percent CI, 2.60 to 8.05; p \u3c 0.001). CONCLUSIONS: Liposuction by board-certified plastic surgeons is safe, with a low risk of life-threatening complications. Traditional liposuction volume thresholds do not accurately convey individualized risk. The authors\u27 risk assessment model demonstrates that volumes in excess of 100 ml per unit of body mass index confer an increased risk of complications. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III