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The effects of obesity on resuscitation after severe burn are not well understood. Formulas to calculate 24-h resuscitation volumes incorporate body weight, which in obese patients often leads to excessive fluid administration and potential complications such as pulmonary edema, extremity or abdominal compartment syndrome, and longer mechanical ventilation. We evaluated the impact of obesity on 24-h fluid resuscitation after severe burn using a cohort of 145 adults admitted to the burn ICU from January 2014 to March 2017 with20% total body surface area burns. Patients were divided into four groups based on body mass index: normal weight (index of25), overweight (25-29.9), obese (30-39.9), and morbidly obese (40). Median total body surface area burn was 39.4% (interquartile range: 23.5%-49.5%). Patients were 74.5% male and demographics and injury characteristics were similar across groups. Resuscitation volumes exceeded the predicted Parkland formula volume in the normal and overweight groups but were less than predicted in the obese and morbidly obese categories (p0.001). No difference was found in 24-h urine output between groups (p=0.08). Increasing body mass index was not associated with increased use of renal replacement therapy. Only total body surface area burned, and age were independent predictors of hospital mortality (p0.001). We conclude that using body weight to calculate resuscitation in obese patients results in a predicted fluid volume that is higher than the volume actually given, which can lead to over-resuscitation if rates are not titrated regularly to address fluid responsiveness.

Although the implementation of new treatment models can be a challenging process for health care services, the outcomes can be greatly beneficial to patients and service providers. This article describes the process of change experienced within our multidisciplinary specialist eating disorder service when we implemented a new evidence-based model of care focusing on outpatient family-based treatment (FBT). Clinical outcomes were positive, including a 56% decrease in admissions, a 75% decrease in readmissions, and a 51% decrease in total bed days. Of families referred to FBT, 83% completed treatment and 97% of completers achieved >90% of their expected body weight. Despite these gains, many challenges were experienced, including misgivings about the suitability of FBT and difficulties in adhering to changes in professional roles. We describe these challenges, describe how they were overcome, and review factors perceived to be critical to the program's success, including integration of medical and mental health services, communication, and training.

CTP:phosphocholine cytidylyltransferase (CCT), an amphitropic enzyme that regulates phosphatidylcholine synthesis, is composed of a catalytic head domain and a regulatory tail. The tail region has dual functions as a regulator of membrane binding/enzyme activation and as an inhibitor of catalysis in the unbound form of the enzyme, suggesting conformational plasticity. These functions are well conserved in CCTs across diverse phyla, although the sequences of the tail regions are not. CCT regulatory tails of diverse origins are composed of a long membrane lipid-inducible amphipathic helix (m-AH) followed by a highly disordered segment, reminiscent of the Parkinson disease-linked protein, α-synuclein, which we show shares a novel sequence motif with vertebrate CCTs. To unravel features required for silencing, we created chimeric enzymes by fusing the catalytic domain of rat CCTα to the regulatory tail of CCTs from Drosophila, Caenorhabditis elegans, or Saccharomyces cerevisiae or to α-synuclein. Only the tail domains of the two invertebrate CCTs were competent for both suppression of catalytic activity and for activation by lipid vesicles. Thus, both silencing and activating functions of the m-AH can tolerate significant changes in length and sequence. We identified a highly amphipathic 22-residue segment in the m-AH with features conserved among animal CCTs but not yeast CCT or α-synuclein. Deletion of this segment from rat CCT increased the lipid-independent V(max) by 10-fold, equivalent to the effect of deleting the entire tail, and severely weakened membrane binding affinity. However, membrane binding was required for additional increases in catalytic efficiency. Thus, full activation of CCT may require not only loss of a silencing conformation in the m-AH but a gain of an activating conformation, promoted by membrane binding.

The Bcl-2 family regulates induction of apoptosis at the mitochondria. Essential to this regulation are the interactions between Bcl-2 family members, which are mediated by Bcl-2 homology (BH) domains. Vaccinia virus F1L is a unique inhibitor of apoptosis that lacks significant sequence similarity with the Bcl-2 family and does not contain obvious BH domains. Despite this, F1L inhibits cytochrome c release from mitochondria by preventing Bak and Bax activation. Although F1L constitutively interacts with Bak to prevent Bak activation, the precise mechanism of this interaction remains elusive. We have identified highly divergent BH domains in F1L that were verified by the recent crystal structure of F1L (Kvansakul, M., Yang, H., Fairlie, W. D., Czabotar, P. E., Fischer, S. F., Perugini, M. A., Huang, D. C., and Colman, P. M. (2008) Cell Death Differ. 15, 1564-1571). Here we show that F1L required these BH domains to interact with ectopically expressed and endogenous Bak. The interaction between F1L and Bak was conserved across species, and both F1L and the cellular antiapoptotic protein Mcl-1 required the Bak BH3 domain for interaction. Moreover, F1L replaced Mcl-1 during infection, as the Bak x Mcl-1 complex was disrupted during vaccinia virus infection. In contrast to UV irradiation, vaccinia virus infection did not result in rapid degradation of Mcl-1, consistent with our observation that vaccinia virus did not initiate a DNA damage response. Additionally, Mcl-1 expression prevented Bak activation and apoptosis during infection with a proapoptotic vaccinia virus devoid of F1L. Our data suggest that F1L replaces the antiapoptotic activity of Mcl-1 during vaccinia virus infection by interacting with Bak using highly divergent BH domains.

Vitronectin is an abundant plasma protein that regulates coagulation, fibrinolysis, complement activation, and cell adhesion. Recently, we demonstrated that plasma vitronectin inhibits fibrinolysis by mediating the interaction of type 1 plasminogen activator inhibitor with fibrin (Podor, T. J., Peterson, C. B., Lawrence, D. A., Stefansson, S., Shaughnessy, S. G., Foulon, D. M., Butcher, M., and Weitz, J. I. (2000) J. Biol. Chem. 275, 19788–19794). The current studies were undertaken to further examine the interactions between vitronectin and fibrin(ogen). Comparison of vitronectin levels in plasma with those in serum indicates that ∼20% of plasma vitronectin is incorporated into the clot. When the time course of biotinylated-vitronectin incorporation into clots formed from125I-fibrinogen is monitored, vitronectin incorporation into the clot parallels that of fibrinogen in the absence or presence of activated factor XIII. Vitronectin binds specifically to fibrin matrices with an estimated K d of ∼0.6 μm. Additional vitronectin subunits are assembled on fibrin-bound vitronectin multimers through self-association. Confocal microscopy of fibrin clots reveals the globular vitronectin aggregates anchored at intervals along the fibrin fibrils. This periodicity raised the possibility that vitronectin interacts with the γA/γ′ variant of fibrin(ogen) that represents about 10% of total fibrinogen. In support of this concept, the vitronectin which contaminates fibrinogen preparations co-purifies with the γA/γ′ fibrinogen fraction, and clots formed from γA/γ′ fibrinogen preferentially bind vitronectin. These studies reveal that vitronectin associates with fibrin during coagulation, and may thereby modulate hemostasis and inflammation.

Three-dimensional structure analyses of two polysaccharide degrading enzymes, α-amylase and α-mannosidase, though not yet complete, reveal that both enzymes are structural tandem duplicates and that the two similar domains within each are related by a dyad axis of symmetry.

The structure to 3.0 A resolution of the protein canavalin from Jack beans has been determined by conventional X-ray crystallographic techniques. We present evidence that canavalin is a proteolytically modified form of the enzyme α- d -mannosidase. This is based on the facts that the purified precursor protein possesses substantial α- d -mannosidase activity; it comigrates on SDS-PAGE with Jack bean α- d -mannosidase prepared by other means; and its oligomer molecular weight and Zn 2+ content are the same as those of Jack bean α- d -mannosidase.