Structural and immunologic characterization of bovine, horse, and rabbit serum albumins

Serum albumin (SA) is the most abundant plasma protein in mammals. SA is a multifunctional protein with extraordinary ligand binding capacity, making it a transporter molecule for a diverse range of metabolites, drugs, nutrients, metals and other molecules. Due to its ligand binding properties, albumins have wide clinical, pharmaceutical, and biochemical applications. Albumins are also allergenic, and exhibit a high degree of cross-reactivity due to significant sequence and structure similarity of SAs from different organisms. Here we present crystal structures of albumins from cattle (BSA), horse (ESA) and rabbit (RSA) sera. The structural data are correlated with the results of immunological studies of SAs. We also analyze the conservation or divergence of structures and sequences of SAs in the context of their potential allergenicity and cross-reactivity. In addition, we identified a previously uncharacterized ligand binding site in the structure of RSA, and calcium binding sites in the structure of BSA, which is the first serum albumin structure to contain metal ions.     

Oxymetazoline inhibits proinflammatory reactions: effect on arachidonic acid-derived metabolites

The nasal decongestant oxymetazoline effectively reduces rhinitis symptoms. We hypothesized that oxymetazoline affects arachidonic acid-derived metabolites concerning inflammatory and oxidative stress-dependent reactions. The ability of oxymetazoline to model pro- and anti-inflammatory and oxidative stress responses was evaluated in cell-free systems, including 5-lipoxygenase (5-LO) as proinflammatory, 15-lipoxygenase (15-LO) as anti-inflammatory enzymes, and oxidation of methionine by agglomerates of ultrafine carbon particles (UCPs), indicating oxidative stress. In a cellular approach using canine alveolar macrophages (AMs), the impact of oxymetazoline on phospholipase A(2) (PLA(2)) activity, respiratory burst and synthesis of prostaglandin E(2) (PGE(2)), 15(S)-hydroxy-eicosatetraenoic acid (15-HETE), leukotriene B(4) (LTB(4)), and 8-isoprostane was measured in the absence and presence of UCP or opsonized zymosan as particulate stimulants. In cell-free systems, oxymetazoline (0.4-1 mM) inhibited 5-LO but not 15-LO activity and did not alter UCP-induced oxidation of methionine. In AMs, oxymetazoline induced PLA(2) activity and 15-HETE at 1 mM, enhanced PGE(2) at 0.1 mM, strongly inhibited LTB(4) and respiratory burst at 0.4/0.1 mM (p < 0.05), but did not affect 8-isoprostane formation. In contrast, oxymetazoline did not alter UCP-induced PLA(2) activity and PGE(2) and 15-HETE formation in AMs but inhibited UCP-induced LTB(4) formation and respiratory burst at 0.1 mM and 8-isoprostane formation at 0.001 mM (p < 0.05). In opsonized zymosan-stimulated AMs, oxymetazoline inhibited LTB(4) formation and respiratory burst at 0.1 mM (p < 0.05). In conclusion, in canine AMs, oxymetazoline suppressed proinflammatory reactions including 5-LO activity, LTB(4) formation, and respiratory burst and prevented particle-induced oxidative stress, whereas PLA(2) activity and synthesis of immune-modulating PGE(2) and 15-HETE were not affected.     

Chaperonin GroEL and its mutant D87K protect from ischemia in vivo and in vitro

Protein aggregation and misfolding are central mechanisms of both acute and chronic neurodegeneration. Overexpression of chaperone Hsp70 protects from stroke in animal and cell culture models. Although it is accepted that chaperones protect cells, the mechanism of protection by chaperones in ischemic injury is poorly understood. In particular, the relative importance of preventing protein aggregation compared to facilitating correct protein folding during ischemia and recovery is not known. To test the importance of protein folding and minimize interaction with co-chaperones we studied the bacterial chaperonin GroEL (HSPD1) and a folding-deficient mutant D87K. Both molecules protected cells from ischemia-like injury, and reduced infarct volume and improved neurological outcome after middle cerebral artery occlusion in rats. Protection was associated with reduced protein aggregation, assessed by ubiquitin immunohistochemistry. Marked neuroprotection by the folding-deficient chaperonin demonstrates that inhibition of aggregation is sufficient to protect the brain from ischemia. This suggests that strategies to maintain protein solubility and inhibit aggregation in the face of acute insults such as stroke may be a useful protective strategy.     

Diagnostic potential of Ag85C in comparison to various secretory antigens for childhood tuberculosis

Childhood tuberculosis is difficult to diagnose. A rapid, simple and relatively inexpensive diagnostic test will be crucial to future control efforts. Therefore, efficacy and diagnostic potential of different secretory antigens of Mycobacterium tuberculosis (CFP-10, Ag85complex, Ag85 A, B, C) and their combinations along with ESAT-6 in the detection of antibody profiles of childhood tuberculosis cases were evaluated using ELISA technique and reactivity was compared with the gold standards (smear, culture and IS6110 targeted PCR). In the present study, 88 fresh, untreated childhood tuberculosis (TB) cases, 17 children undergoing anti-tubercular therapy, 17 children having disease other than TB and 25 healthy children were included. ROC curve analysis was used to calculate the sensitivity and specificity of each antigen for antibody detection. Ag85C was found to be showing highest sensitivity of 89.77% and specificity of 92% among all the antigens used ( P  < 0.0001). Positivity with antigen was 95% in smear and culture negative patients. Antibody reactivity was noted in 92.62% of patients who were positive for IS6110 by PCR. Cocktail of all the antigens showed 67.1% sensitivity and 80% of specificity. Sensitivity of 29.55%, 57.95%, 64.77% and specificity of 80%, 72%, 64% was observed using CFP-10, Ag85complex and Ag85B. Low reactivity of 31.82% in patients and least specificity of 24% was noted with Ag85A. Our finding demonstrates the potential of Ag85C in the detection of antibody in childhood TB cases and this antigen showed good concordance with PCR positivity.     

Conversion and safety in off-pump coronary artery bypass: a system failure that needs re-emphasis

Institution of cardiopulmonary bypass after commencement of "off-pump" coronary artery bypass surgery is known as conversion. This may be an emergency or elective process. The phenomenon of conversion, although widely reported, remains under-emphasized. Emergency conversion may lead to poorer patient outcomes and therefore warrants serious consideration. The rate of conversion may influence the results of randomized controlled trials, and be considered a surrogate performance indicator of surgical competence in off-pump coronary artery bypass. Several causes and predictors of conversion are reported in published literature. This article aims to examine the phenomenon of conversion in off-pump coronary artery bypass and proposes a framework for its prevention.     

Single centre guidelines for radiological follow-up based on 775 patients treated by cytoreductive surgery and HIPEC for appendiceal pseudomyxoma peritonei

Aim

Pseudomyxoma peritonei (PMP) is an uncommon malignancy, generally originating from a ruptured epithelial tumour of the appendix. Despite successful cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC), some patients recur. Currently there are no guidelines on the methods, frequency and intensity of follow-up.