Pooled analysis of WHO Surgical Safety Checklist use and mortality after emergency laparotomy

Background The World Health Organization (WHO) Surgical Safety Checklist has fostered safe practice for 10 years, yet its place in emergency surgery has not been assessed on a global scale. The aim of this study was to evaluate reported checklist use in emergency settings and examine the relationship with perioperative mortality in patients who had emergency laparotomy. Methods In two multinational cohort studies, adults undergoing emergency laparotomy were compared with those having elective gastrointestinal surgery. Relationships between reported checklist use and mortality were determined using multivariable logistic regression and bootstrapped simulation. Results Of 12 296 patients included from 76 countries, 4843 underwent emergency laparotomy. After adjusting for patient and disease factors, checklist use before emergency laparotomy was more common in countries with a high Human Development Index (HDI) (2455 of 2741, 89.6 per cent) compared with that in countries with a middle (753 of 1242, 60.6 per cent; odds ratio (OR) 0.17, 95 per cent c.i. 0.14 to 0.21, P <0001) or low (363 of 860, 422 per cent; OR 008, 007 to 010, P <0.001) HDI. Checklist use was less common in elective surgery than for emergency laparotomy in high-HDI countries (risk difference -94 (95 per cent c.i. -11.9 to -6.9) per cent; P <0001), but the relationship was reversed in low-HDI countries (+121 (+7.0 to +173) per cent; P <0001). In multivariable models, checklist use was associated with a lower 30-day perioperative mortality (OR 0.60, 0.50 to 073; P <0.001). The greatest absolute benefit was seen for emergency surgery in low- and middle-HDI countries. Conclusion Checklist use in emergency laparotomy was associated with a significantly lower perioperative mortality rate. Checklist use in low-HDI countries was half that in high-HDI countries.Peer reviewe

Global variation in anastomosis and end colostomy formation following left-sided colorectal resection

Background End colostomy rates following colorectal resection vary across institutions in high-income settings, being influenced by patient, disease, surgeon and system factors. This study aimed to assess global variation in end colostomy rates after left-sided colorectal resection. Methods This study comprised an analysis of GlobalSurg-1 and -2 international, prospective, observational cohort studies (2014, 2016), including consecutive adult patients undergoing elective or emergency left-sided colorectal resection within discrete 2-week windows. Countries were grouped into high-, middle- and low-income tertiles according to the United Nations Human Development Index (HDI). Factors associated with colostomy formation versus primary anastomosis were explored using a multilevel, multivariable logistic regression model. Results In total, 1635 patients from 242 hospitals in 57 countries undergoing left-sided colorectal resection were included: 113 (6·9 per cent) from low-HDI, 254 (15·5 per cent) from middle-HDI and 1268 (77·6 per cent) from high-HDI countries. There was a higher proportion of patients with perforated disease (57·5, 40·9 and 35·4 per cent; P < 0·001) and subsequent use of end colostomy (52·2, 24·8 and 18·9 per cent; P < 0·001) in low- compared with middle- and high-HDI settings. The association with colostomy use in low-HDI settings persisted (odds ratio (OR) 3·20, 95 per cent c.i. 1·35 to 7·57; P = 0·008) after risk adjustment for malignant disease (OR 2·34, 1·65 to 3·32; P < 0·001), emergency surgery (OR 4·08, 2·73 to 6·10; P < 0·001), time to operation at least 48 h (OR 1·99, 1·28 to 3·09; P = 0·002) and disease perforation (OR 4·00, 2·81 to 5·69; P < 0·001). Conclusion Global differences existed in the proportion of patients receiving end stomas after left-sided colorectal resection based on income, which went beyond case mix alone

Human monoclonal antibodies to the S glycoprotein and related proteins as potential therapeutics for SARS

Polyclonal antibodies have a century-old history of being effective against some viruses and, recently, monoclonal antibodies (mAbs) have also shown some clinical success. Human mAbs to the severe acute respiratory syndrome (SARS) coronavirus spike glycoprotein have been developed by several research groups at an amazing pace. These antibodies potently neutralize infectious virus in tissue cultures and animal models, and, alone or in combination with vaccines and other drugs, may have potential for the prevention and treatment of SARS. © The Thomson Corporation.link_to_subscribed_fulltex

Antibody-based inhibitors of HIV infection

The demand for new treatment options against HIV is becoming increasingly desperate as the side effects and the expansion and spread of drug-resistant virus within the infected population limit the clinical benefits provided by available anti-HIV drugs. Preparations of polyclonal antibodies have a long history of proven clinical utility against some viruses; however, they have enjoyed very limited success against HIV. Recent clinical trials and in vitro experiments suggest that monoclonal antibodies against HIV may have promise clinically. These antibodies and antibody-based reagents target either the viral envelope glycoprotein, the receptor (CD4) or coreceptor (CCR5) molecules, or transition-state structures that appear during viral entry. The challenge is whether an antibody-based therapy can be identified (with or without their small molecule brethren) that presents long-term clinical efficacy, lowtoxicity and minimal risk of clinical failure from viral resistance.link_to_subscribed_fulltex

Increased efficacy of HIV-1 neutralization by antibodies at low CCR5 surface concentration

It has been observed that some antibodies, including the CD4-induced (CD4i) antibody IgG X5 and the gp41-specific antibody IgG 2F5, exhibit higher neutralizing activity in PBMC-based assays than in cell line based assays [J.M. Binley, T. Wrin, B. Korber, M.B. Zwick, M. Wang, C. Chappey, G. Stiegler, R. Kunert, S. Zolla-Pazner, H. Katinger, C.J. Petropoulos, D.R. Burton, Comprehensive cross-clade neutralization analysis of a panel of anti-human immunodeficiency virus type 1 monoclonal antibodies, J. Virol. 78 (2004) 13232-13252]. It has been hypothesized that the lower CCR5 concentration on the surface of the CD4 T lymphocytes compared to that on cell lines used for the neutralization assays could be a contributing factor to the observed differences in neutralizing activity. To test this hypothesis and to further elucidate the contribution of CCR5 concentration differences on antibody neutralizing activity, we used a panel of HeLa cell lines with well-defined and differential surface concentrations of CCR5 and CD4 in a pseudovirus-based assay. We observed that the CCR5 cell surface concentration but not the CD4 concentration had a significant effect on the inhibitory activity of X5 and several other CD4i antibodies including 17b and m9, as well as that of the gp41-specifc antibodies 2F5 and 4E10 but not on that of the CD4 binding site antibody (CD4bs), b12. The 50% inhibitory concentration (IC50) decreased up to two orders of magnitude in cell lines with low CCR5 concentration corresponding to that in CD4 T cells used in PBMC-based assays (about 103 per cell) compared to cell lines with high CCR5 concentration (about 104 or more). Our results suggest that the CCR5 cell surface concentration could be a contributing factor to the high neutralizing activities of some antibodies in PBMC-based-assays but other factors could also play an important role. These findings could have implications for development of vaccine immunogens based on the epitopes of X5 and other CD4i antibodies, for elucidation of the mechanisms of HIV-1 neutralization by antibodies, and for design of novel therapeutic approaches.link_to_subscribed_fulltex

Selection of a novel gp41-specific HIV-1 neutralizing human antibody by competitive antigen panning

The HIV envelope glycoprotein (Env) is composed of two non-covalently associated subunits: gp120 and gp41. Panning of phage-displayed antibody libraries against Env-based antigens has resulted mostly in selection of anti-gp120 antibodies. Native gp41 in the absence of gp120 is unstable. The use of gp41 fragments as antigens has resulted in selection of antibodies with only relatively modest neutralizing activity. To enhance selection of antibodies specific for gp41 in the context of the whole Env we developed a methodology termed competitive antigen panning (CAP). Using CAP, we identified a novel gp41-specific human monoclonal antibody (hmAb), m48, from an immune library derived from long-term nonprogressors with high titers of broadly cross-reactive neutralizing antibodies (bcnAbs). Selection of m48 was only successful using CAP and not through the conventional pre-incubation methodology. In assays based on spreading infection in peripheral blood mononuclear cells (PBMCs) m48 neutralized a panel of HIV-1 primary isolates from different clades more potently than the well-characterized broadly cross-reactive HIV-1-neutralizing antibodies IgG1 4E10 and Fab Z13. These results may have implications for the selection of novel gp41-specific bcnAbs and other antibodies, and for the development of HIV-1 inhibitors and vaccine immunogens. © 2006 Elsevier B.V. All rights reserved.link_to_subscribed_fulltex

Identification and characterization of a new cross-reactive human immunodeficiency virus type 1-neutralizing human monoclonal antibody

The identification and characterization of new human monoclonal antibodies (hMAbs) able to neutralize primary human immunodeficiency virus type 1 (HIV-1) isolates from different subtypes may help in our understanding of the mechanisms of virus entry and neutralization and in the development of entry inhibitors and vaccines. For enhanced selection of broadly cross-reactive antibodies, soluble HIV-1 envelope glycoproteins (Envs proteins) from two isolates complexed with two-domain soluble CD4 (sCD4) were alternated during panning of a phage-displayed human antibody library; these two Env proteins (89.6 and IIIB gp140s), and one additional Env (JR-FL gp120) alone and complexed with sCD4 were used for screening. An antibody with relatively long HCDR3 (17 residues), designated m14, was identified that bound to all antigens and neutralized heterologous HIV-1 isolates in multiple assay formats. Fab m14 potently neutralized selected well-characterized subtype B isolates, including JRCSF, 89.6, IIIB, and Yu2. Immunoglobulin G1 (IgG1) m14 was more potent than Fab m14 and neutralized 7 of 10 other clade B isolates; notably, although the potency was on average significantly lower than that of IgG1 b12, IgG1 m14 neutralized two of the isolates with significantly lower 50% inhibitory concentrations than did IgG1 b12. IgG1 m14 neutralized four of four selected clade C isolates with potency higher than that of IgG1 b12. It also neutralized 7 of 17 clade C isolates from southern Africa that were difficult to neutralize with other hMAbs and sCD4. IgG1 m14 neutralized four of seven primary HIV-1 isolates from other clades (A, D, E, and F) much more efficiently than did IgG1 b12; for the other three isolates, IgG b12 was much more potent. Fab m14 bound with high (nanomolar range) affinity to gp120 and gp140 from various isolates; its binding was reduced by soluble CD4 and antibodies recognizing the CD4 binding site (CD4bs) on gp120, and its footprint as defined by alanine-scanning mutagenesis overlaps that of b12. These results suggest that m14 is a novel CD4bs cross-reactive HIV-1-neutralizing antibody that exhibits a different inhibitory profile compared to the only known potent broadly neutralizing CD4bs human antibody, b12, and may have implications for our understanding of the mechanisms of immune evasion and for the development of inhibitors and vaccines.link_to_subscribed_fulltex

Corrigendum to "Cross-reactive HIV-1 neutralizing monoclonal antibodies selected by screening of an immune human phage library against an envelope glycoprotein (gp140) isolated from a patient (R2) with broadly HIV-1 neutralizing antibodies" [Virology 363 (2007) 79-90] (DOI:10.1016/j.virol.2007.01.015)

link_to_subscribed_fulltex

Cross-reactive HIV-1 neutralizing monoclonal antibodies selected by screening of an immune human phage library against an envelope glycoprotein (gp140) isolated from a patient (R2) with broadly HIV-1 neutralizing antibodies

Elicitation of broadly cross-reactive neutralizing antibodies (bcnAbs) in HIV infections is rare. To test the hypothesis that such antibodies could be elicited by HIV envelope glycoproteins (Envs) with unusual immunogenic properties and to identify novel bcnAbs, we used a soluble Env ectodomain (gp140) from a donor (R2) with high level of bcnAbs as an antigen for panning of an immune phage-displayed antibody library. The panning with the R2 Env resulted in significantly higher number of cross-reactive antibody clones than by using Envs from two other isolates (89.6 and IIIB). Two of the identified human monoclonal antibodies (hmAbs), m22 and m24, had sequences, neutralizing and binding activities similar or identical to those of the gp120-specific bcnAbs m18 and m14. The use of the R2 Env but not other Envs for panning resulted in the identification of a novel gp41-specific hmAb, m46. For several of the tested HIV-1 primary isolates its potency on molar basis was comparable to that of T20. It inhibited entry of primary isolates from different clades with an increased activity for cell lines with low CCR5 surface concentrations. The m46 neutralizing activity against a panel of clade C isolates was significantly higher in an assay based on peripheral blood mononuclear cells (4 out of 5 isolates were neutralized with an IC50 in the range from 1.5 to 25 μg/ml) than in an assay based on a cell line with relatively high concentration of cell-surface-associated CCR5. In contrast to 2F5 and Z13, this antibody did not bind to denatured gp140 and gp41-derived peptides indicating a conformational nature of its epitope. It bound to a 5-helix bundle but not to N-heptad repeat coiled coils and a 6-helix bundle construct indicating contribution of both gp41 heptad repeats to its epitope and to a possible mechanism of neutralization. These results indicate that the R2 Env may contain unique exposed conserved epitopes that could contribute to its ability to elicit broadly cross-reactive antibodies in animals and humans; the newly identified antibodies may help in the development of novel vaccine immunogens and therapeutics. © 2007 Elsevier Inc. All rights reserved.link_to_subscribed_fulltex