Effects of enrofloxacin, flunixin meglumine and dexamethasone on disseminated intravascular coagulation, cytokine levels and adenosine deaminase activity in endotoxaemia in rats

The aim of this study was to determine the effects of drugs used in the treatment of endotoxaemia on disseminated intravascular coagulation, cytokine levels and adenosine deaminase activities in endotoxaemic rats. Rats were divided into seven groups. Lipopolysaccharide (LPS) was injected into all groups, including the positive control group. The other six groups received the following drugs: enrofloxacin (ENR), flunixin meglumine (FM), low-dose dexamethasone (DEX), high-dose DEX, ENR + FM + low-dose DEX, and ENR + FM + high-dose DEX. After the treatments, serum and plasma samples were collected at 0, 1, 2, 4, 6, 8, 12, 24 and 48 hours (h). A coagulometer was used to determine the levels of coagulation values, while ELISA was used to assay serum cytokines and adenosine deaminase (ADA). Low-dose DEX alone and combined treatments depressed the levels of cytokines and ADA (from 371 to 70 IU/L at 6 h) significantly and inhibited the decrease of coagulation values (antithrombin from 67 to 140% at 6 h, fibrinogen from 54 to 252 mg/dL at 6 h). In summary, FM + high-dose DEX may be the preferred treatment of endotoxaemia because of its highest effectiveness. FM plus high-dose DEX may be a new therapy for endotoxaemic domestic animals.

Congenital afibrinogenemia: intracellular retention of fibrinogen due to a novel W437G mutation in the fibrinogen Bβ-chain gene

Congenital afibrinogenemia is a rare autosomal recessive coagulation disorder characterised by hemorrhagic manifestations of variable entity and by severe plasma fibrinogen deficiency. Among the 31 afibrinogenemia-causing mutations so far reported, only 2 are missense mutations and both are located in the fibrinogen Bbeta-chain gene. Direct sequencing of the fibrinogen gene cluster in two afibrinogenemic Iranian siblings revealed a novel homozygous T>G transversion in exon 8 (nucleotide position 8025) of the fibrinogen Bbeta-chain gene. The resulting W437G missense mutation involves a highly conserved amino acid residue, located in the C-terminal globular D domain. The role of the W437G amino acid substitution on fibrinogen synthesis, folding, and secretion was assessed by in vitro expression experiments in COS-1 cells, followed by qualitative and quantitative analyses of intracellular and secreted mutant fibrinogen. Results of both pulse-chase experiments and enzyme-linked immunosorbent assays demonstrated intracellular retention of the mutant W437G fibrinogen and marked reduction of its secretion. These data, besides elucidating the pathogenetic role of the W437G mutation in afibrinogenemia, underline the importance of the Bbeta-chain D domain in fibrinogen folding and secretion.