Inhibition of endotoxin-induced activation of the coagulation and fibrinolytic pathways using a recombinant endotoxin-binding protein (rBPI23)

A recombinant endotoxin-neutralizing protein, rBPI23, was shown to partially prevent endotoxin-induced activation of the fibrinolytic and coagulation systems in experimental endotoxemia in humans. In a placebo- controlled, blinded crossover study, eight volunteers were challenged twice with an intravenous bolus injection of endotoxin (40 EU/kg of body weight) and concurrently received either rBPI23 (1 mg/kg) or placebo (human serum albumin, 0.2 mg/kg). rBPI23 treatment significantly lowered the endotoxin-induced fibrinolytic response, ie, reduced the release of tissue-type plasminogen activator, urokinase- type plasminogen activator, plasminogen activator inhibitor antigen, and complex formation of plasmin alpha 2-antiplasmin (P = .0078 for each). Plasminogen activator inhibitor activity was also reduced, but not significantly according to the Hochberg method (P = .0304). The endotoxin-induced activation of the procoagulant state as reflected by increase in F1 + 2 fragments and TAT complexes was blunted by rBPI23 infusion (P = .0391 [not significant according to the Hochberg method] and .0078, respectively). These results indicate that rBPI23 is capable of reducing both the activation of the fibrinolytic and the coagulation systems after low-dose endotoxin infusion in humans.     

Chemoattractant-induced changes in surface expression and redistribution of a functional ligand for P-selectin on neutrophils

Adhesion between platelets and neutrophils is mediated through the interaction of P-selectin on activated platelets with a carbohydrate- containing structure on neutrophils, and occurs under both static and shear conditions. Recent studies using flow chambers have shown that neutrophils become activated after binding to surface-adherent platelets expressing P-selectin. The objective of the present study was to investigate the effect of such activation on the interactions of platelet P-selectin with its ligand on neutrophils. Flow cytometric analyses using P-selectin chimeras revealed that activation induced a rapid and marked reduction in chimera binding, with levels of binding decreased by 71% after 15 minutes of stimulation with the chemotactic agent, FMLP. Using a visual assay of platelet-neutrophil rosetting, we showed that the P-selectin ligand was translocated and clustered at the uropod of neutrophils following the shape changes and polarization induced by chemotactic stimulation. Activated neutrophils bound to surface-adherent platelets also displayed the clustering of P-selectin ligand at the uropod, and these neutrophils detached from the platelets when a shear stress (2 dynes/cm2) was applied through the adhesion chamber. These results indicate that chemotactic stimulation of neutrophils induces changes in the surface expression and distribution of a biologically relevant ligand for P-selectin, and that these changes might influence the adhesive interactions occurring between neutrophils and activated platelets.     

Comparison of Dexmedetomidine–Ketamine with Isoflurane for Anesthesia of Chinchillas (Chinchilla lanigera)

The objective of this study was to compare isoflurane with a combination of dexmedetomidine and ketamine, administered intramuscularly, for anesthesia in chinchillas (Chinchilla lanigera). In a prospective, complete crossover study, adult chinchillas (n = 8; age, 2 to 5 y) were anesthetized with a combination of dexmedetomidine (0.015 mg/kg IM) and ketamine (4 mg/kg IM). Atipamezole (0.15 mg/kg) was injected subcutaneously 45 min after dexmedetomidine–ketamine administration. For comparison, anesthesia also was induced and maintained with isoflurane in 100% oxygen, delivered by facemask. Anesthetic and physiologic parameters were recorded during each anesthesia, including various reflexes, heart rate, respiratory rate, body temperature, and SpO₂. Food intake, fecal output, and body weight were recorded daily for 6 d after each anesthetic trial. Induction time, heart rate, respiratory rate, and body temperature did not differ significantly between the 2 anesthetic protocols. Recovery times were shorter and SpO₂ was higher in animals that received isoflurane delivered in 100% oxygen. Food intake and fecal output were reduced in the dexmedetomidine–ketamine group for as long as 3 d after anesthesia, whereas isoflurane had no signifcant effect on food intake or fecal output. Both anesthetic protocols provided effective anesthesia in chinchillas. However, when anesthetized with dexmedetomidine–ketamine, chinchillas received room air and became hypoxemic. Future studies are needed to evaluate the effect of oxygen supplementation on anesthetic recovery and on the recovery of food intake and fecal output in chinchillas.Abbreviation: DK, dexmedetomidine–ketamineChinchillas are used extensively in research to study otitis media, hearing loss, and ototoxicity.^1,11,19,25 In addition, chinchillas are becoming increasingly popular as companion animals and, therefore, are more frequently presented for veterinary care. Common diseases of chinchillas include dental disease, gastrointestinal disorders, and ocular disorders.^13,14 Chemical immobilization is often required to perform diagnostic (for example, radiography, CT), therapeutic, or experimental procedures.^3,5,7,21 Research regarding the efficacy and safety of anesthetic protocols in chinchillas is limited and currently recommended protocols rely largely on extrapolation from other species or anecdotal reports.^13,21,27Isoflurane is used routinely in chinchillas for the induction and maintenance of anesthesia. A study investigating the echocardiographic effects of isoflurane in chinchillas found significant effects on several echocardiographic parameters, but no complications or other side effects were reported.¹² Isoflurane typically is delivered by facemask to chinchillas, given that endotracheal intubation is technically challenging and therefore not performed routinely.^10,21 However, using a facemask increases the risk of exposure of the veterinary staff to waste gases, which is a significant occupational health concern.^20,23 Therefore, alternative anesthetic protocols that reduce waste-gas exposure are desired, such as exclusively using injectable anesthetic drugs for induction and maintenance of anesthesia. Intravascular access is challenging to obtain in conscious chinchillas, and thus parenteral, nonvascular protocols provide the most accommodating route for anesthesia induction and maintenance.¹⁴ Only one study in chinchillas has investigated the effects of various injectable anesthetics: a combination of medetomidine (0.06 mg/kg) and ketamine (5 mg/kg) was compared with other parenteral protocols.¹⁴ Although anesthesia was successful with this protocol, the authors reported respiratory and cardiac depression in the animals. Furthermore, although atipamezole is commonly administered in clinical and research settings to promote rapid recovery and prevent complications, such as hypothermia, it was not used in the cited study.¹⁴To our knowledge, no studies have been published that assess the effects of anesthetic protocols on recovery of food intake and fecal output in chinchillas. The objective of this study was to compare the anesthesia induced in chinchillas by using either dexmedetomidine and ketamine or isoflurane and to evaluate the effects of both anesthetic protocols on subsequent food intake, fecal output, and body weight.     

Germline mutations predisposing to melanoma

Nearly 15% of melanomas occur in patients with a family history and a subset of these patients have a germline mutation in a melanoma predisposing gene. CDKN2A mutations are responsible for the majority of hereditary melanoma, but many other susceptibility genes have been discovered in recent years, including CDK4, TERT, ACD, TERF2IP, POT1, MITF, MC1R, and BAP1. Additionally, melanoma risk is increased in mixed cancer syndromes caused by mutations in PTEN, BRCA2, BRCA1, RB1, and TP53. While early onset, multiple tumors, and family cancer history remain the most valuable clinical clues for hereditary melanoma, characteristic epithelioid cytology of melanocytic tumors may suggest an underlying BAP1 mutation. Herein, we review the clinical and histopathologic characteristics of melanocytic tumors associated with these germline mutations and discuss the role of genetic counseling.     

Phenotype determining alleles in GM1 gangliosidosis patients bearing novel GLB1 mutations

Hofer D, Paul K, Fantur K, Beck M, Roubergue A, Vellodi A, Poorthuis BJ, Michelakakis H, Plecko B, Paschke E. Phenotype determining alleles in GM1 gangliosidosis patients bearing novel GLB1 mutations. GM1 gangliosidosis manifests with progressive psychomotor deterioration and dysostosis of infantile, juvenile, or adult onset, caused by alterations in the structural gene coding for lysosomal acid ß‐galactosidase (GLB1). In addition, allelic variants of this gene can result in Morquio B disease (MBD), a phenotype with dysostosis multiplex and entire lack of neurologic involvement. More than 100 sequence alterations in the GLB1 gene have been identified so far, but only few could be proven to be predictive for one of the GM1 gangliosidosis subtypes or MBD. We performed genotype analyses in 16 GM1 gangliosidosis patients of all phenotypes and detected 28 different genetic lesions. Among these, p.I55FfsX16, p.W65X, p.F107L, p.H112P, p.C127Y, p.W161X, p.I181K, p.C230R, p.W273X, p.R299VfsX5, p.A301V, p.F357L, p.K359KfsX23, p.L389P, p.D448V, p.D448GfsX8, and the intronic mutation IVS6‐8A>G have not been published so far. Due to their occurrence in homozygous patients, four mutations could be correlated to a distinct GM1 gangliosidosis phenotype. Furthermore, the missense mutations from heteroallelic patients and three artificial nonsense mutations were characterized by overexpression in COS‐1 cells, and the subcellular localization of the mutant proteins in fibroblasts was assessed. The phenotype specificity of 10 alleles can be proposed on the basis of our results and previous data.