m. ahmadinejad

Snake venoms are rich in valuable substances that have medical potential in the diagnosis and treatment of hemostatic diseases. The present paper was aimed at the purification and functional characterization basis of a thrombin-like enzyme and its role in the functioning of the coagulation cascade and platelet aggregation pathway. A thrombin-like serine protease was purified from the Iranian Echis carinatus venom (TLIECV), employing a one-step chromatographic procedure. This peptide was collected in high yield and purity by a single chromatographic step using RP-HPLC equipped with a C18 column. This peptide showed a 3000 Da molecular weight in gel-electrophoresis. Evidence in the SDS-PAGE gel has confirmed high recovery of fraction in optimal terms. Subsequently, this peptide was identified via its intact molecular mass and peptide mass fingerprint (PMF) using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/MS). Multiple sequence alignments were performed by ClustalW, the Bioedit software. Molegro Data Modeller (MDM) 3.0 software was used to predict the putative tertiary structure of the peptide. The enzyme possessed fibrinogenolytic, procoagulant, and aggregation inducer properties. Moreover, the SDS-PAGE (12%) was applied to examine fibrinogenolytic function. The purified enzyme degraded the Aα chain of fibrinogen while the Bβ and γ chains were not digested. According to that, the deficient human plasma in factor X and normal human plasma were also coagulated by TLIECV, it takes part in the common and intrinsic routes of the coagulation cascade. These findings proved that TLIECV is a serine protease identical to procoagulant thrombin-like snake venom proteases; however, it specifically releases the Aα chain of bovine fibrinogen. Because of its function to make up for the deficiency of factor X and its platelet aggregation inducer property, TLIECV could be considered a molecular impact to reveal the hemostasis mechanisms.

Although von Willebrand's disease (vWD) is the most common hereditary bleeding disorder in the world, the acquired type of the disease (acquired von Willebrand’s syndrome, AvWs) which is seen in some conditions, is less common. Cardiovascular diseases, use of cardiac assistive devices, lymphoproliferative and myeloproliferative disorders are among the most common disorders associated with AvWs. Despite its low prevalence, AvWS is known as a clinically important bleeding disorder.

Considering the importance of the disease, we aimed to investigate and review the disease condition, diagnostic pattern and its clinical and laboratory findings from the disease discovery to the present time by referring to 110 related articles in PubMed, Medline, Scopus and Google Scholar databases.

Clinical and laboratory findings in AvWS and vWD are often similar. So, it can be difficult to distinguish between the two conditions. However, performing screening tests prior to any clinical interventions with a high risk of bleeding, such as surgery, in any individual with an AvWs-associated disorder can greatly facilitate the diagnosis of the disease. Furthermore, a distinction clue between AvWS and vWD is the late onset of AvWS without any previous family and personal history of bleeding.

Conclusions  :

According to published reports, AvWS has been considered as an uncommon disorder. But it seems that its actual prevalence is not rare and compared to what was previously thought, its prevalence is increasing at least in certain groups of patients, due to awareness of specialists especially hemaologists and cardiologists.

Measurement of central venous pressure can be regarded as a beneficial guide in order to assess a patient's hemodynamic status, specifically in patient with sever sepsis and septic shock, for whom a central venous pressure of less than 8mmhg is considered as an indicator for aggressive intravenous fluid replacement. Therefore, this study aimed to investigate the ultrasonographic examination of the inferior vena cava as well caval index in order to estimate low CVP.

This prospective study was performed on 70 patients admitted in ICU of Shahid Bahonar hospital of Kerman who were all reported to utilize central venous catheter. IVC diameter was measured via applying bedside ultrasonography, first at end of inhalation and, second at the end of exhalation. Caval index, indicating the relative decrease in IVC diameter from inhalation to exhalation, was measured via utilizing CVP monitoring.

The study results indicated a positive correlation between inspiratory and expiratory IVC diameter and CVP measurement. The sensitivity of caval index of greater that 50% to predict a low CVP (8mmhg) was reported 94% and it demonstrated the specificity of 97%, as well.

As CVP monitoring is an invasive process, in emergency, ultrasonography can be utilized as an accurate tool to determine low CVP as well as the need for aggressive fluid replacement.