Russell's Viper Research Articles

Thai Russell's viper monospecific antivenom is immunoreactive and effective in neutralizing the venom of Daboia siamensis from Java, Indonesia

Daboia siamensis monovalent antivenom (DSMAV, Thailand) exhibited comparable immunoreactivity toward the venoms of eastern Russell's vipers from Thailand and Indonesia. It also effectively neutralized the procoagulant and lethal effects of both venoms, showing high potency. The Indonesian heterologous trivalent antivenom SABU (Serum Anti Bisa Ular), however, has very weak immunoreactivity and it failed to neutralize the Russell's viper venoms. DSMAV appears to be the appropriate choice of antivenom to treat Russell's viper envenoming.

Evaluation of cultivable aerobic bacterial flora from Russell's viper (Daboia russelii) oral cavity

Snake mouths contain a wide range of bacteria. Identifying these bacteria in snakes is very important to obtain an understanding of the etiological agents of secondary infections that may result from accidents during handling and/or snake bites. The present study aims to determine the pattern of oral bacterial flora of nine healthy Russell's vipers (Daboia russelii), and their susceptibility to common antibiotics. A total of 94 isolates were obtained in pure form, which demonstrated noticeable colony characteristics and which were further studied with several biochemical tests. The strains that showed distinctive colonies, morphology and biochemical parameters were additionally subjected to phylogenetic characterization using 16S rRNA gene sequences. Furthermore, all these isolates were studied for antibiotic susceptibility. The oral cavity of the Russell's viper harbors a wide range of pathogenic bacteria, including Gram-negative genera: Proteus sp., Pseudomonas sp., Salmonella sp., Providencia sp., Alcaligenes sp., Morganella sp., as well as E. coli, and Gram-positive genera: Bacillus and Enterococcus sp., Staphylococcus sp. and Lysinobacillus sp. Most of the isolates were resistant to antibiotics viz. penicillin, Amoxyclav, oxacillin, methicillin and streptomycin while sensitive towards imipenem, amikacin, norfloxacin, gatifloxacin, ciprofloxacin, gentamicin, tetracycline, chloramphenicol and azithromycin. The present study documents diverse bacteria predominant in the oral cavity of Daboia russelii and studied their antibiotic susceptibilities.

The wound healing potential of a pro-angiogenic peptide purified from Indian Russell's viper (Daboia russelii) venom

The cutaneous wound healing property of a pro-angiogenic venom peptide (RVVAP) in a cream-based formulation was evaluated using the excision wound healing model on Wistar strain rats. The wound healing potency and modest antibacterial activity of RVVAP was enhanced significantly (p < 0.05) when combined with Aloe vera extract. RVVAP was also found to be non-toxic at the tested dose of 1.0 mg/kg. Nevertheless, the release of inflammatory cytokines such as IL-1, IL-6, IL-10, and TNF-α in RVVAP-treated mice was suppressed, compared to the untreated controls. This is the first report assessing the wound healing potential of a low-molecular mass, non-enzymatic, pro-angiogenic peptide purified from snake venom.

Characteristics and relative numbers of lethal snake bite cases in medicolegal practice in central Myanmar – A five year study

Clinical and pathological case files of lethal snakebites were reviewed from the Magway Region General Hospital, Magway, Myanmar, over a five-year period (January 2013 December 2017). A total of 2069 postmortem examinations were performed which included 84 cases of lethal snake bite (4.1%). The annual numbers ranged from 10 out of a total of 268 autopsies in 2013 (3.7%), to 31 out of a total of 501 autopsies in 2016 (6.2%). There were 54 males (64%) and 30 females (36%) (M:F = 1.9:1; age range 5–75yrs, mean 33yrs). The most common time for lethal envenomation was August (16/84–19%), the middle of the monsoon season. 45/84 (54%) had acute renal failure, 27/84 (32%) were shocked, and the remaining 12/84 (14%) had disseminated intravascular coagulation. Twenty cases (24%) died within 24 h after envenomation. Fang marks were identified on the legs (either right or left) in 73/84 cases (87%) and on the arms in five cases (6%). The predominant findings at autopsy were of acute renal injury (82/84–98%), pituitary haemorrhage/necrosis (36/84–43%), and adrenal gland haemorrhage (30/84–36%). Despite the reduction in fatalities over the years snakebite from Russell's viper in particular remains an important contributor to mortality in central Myanmar despite the availability of antivenom.

Molecular interaction of phytochemicals with snake venom: Phytochemicals of Andrographis paniculata inhibits phospholipase A2 of Russell's viper (Daboia russelli)

Abstract Andrographis paniculata belonging to Acanthaceae family is an annual herb, traditionally used for venomous bites in various parts of Asia. The plant has various phytochemicals with numerous biological properties which are chemically well characterized and available in the database out of which 22 phytochemicals was used for the study. Our study focuses on finding a lead phytochemical by employing various in-silico methods (Metapocket and Autodock) for the inhibition of venomous protein, namely phospholipase A2. Phospholipase A2 (PLA A2) is conserved in snakes and also considered to be the major toxin possessing equally lethal effect, neurotoxic and myotoxic. Though the PLA A2 three dimensional structure is available, finding the active motif of PLA A2 will make the molecular interaction (docking) studies accurate. Hence, MetaPocket, a tool used for finding the active site as it encompass the results of eight independent pocket site prediction methods. The ability of phytochemical to bind the predicted active site of PLA A2 is carried out with the widely used simulation method, Autodock. Results provided a strong evidence for the presence of multiple putative anti-venom (inhibitor of PLA A2) phytochemicals in A. paniculata (esp., Deoxyandrographolide, Andrograpanin, etc.) and A. paniculata is also found to be a potent free radical scavenger (anti-oxidant) assessed by DPPH in in-vitro condition. Oxidative stress is of major complication reported in snake bitten patient's further worsening the clinical condition and requiring an additional treatment with anti-oxidants in long-term. In conclusion, the phytochemicals of A. paniculata is found to be a potent inhibitor of natural origin targeting PLA A2 to neutralize snake venom.

Inadequate knowledge about snakebite envenoming symptoms and application of harmful first aid methods in the community in high snakebite incidence areas of Myanmar.

IntroductionEvery year millions of people in developing countries suffer from snakebite, causing a large number of deaths and long term complications. Prevention and appropriate first aid could reduce the incidence and improve the health outcomes for those who suffer bites. However, many communities where snakebite is a major issue suffer from a lack of information about prevention and first aid measures that a family or community member could take to prevent severe envenoming, complications and poor outcomes. Myanmar suffers from a high burden of snakebites with a large number of deaths. As part of a health services and community development program, a community survey was conducted to identify communities’ knowledge about snakebite and their sequelae, and knowledge and practice about first aid and health services use.Method4,276 rural residents of Kyaukse and Madaya townships in the Mandalay region were recruited by cluster sampling, involving random selection of 144 villages and random sampling of 30 households from each village. One adult member of each household was interviewed using a structured questionnaire.ResultsThe incidence of snakebite was 116/100,000 people. Respondents reported 15 different types of snakes in the area, with Russell’s Viper, Cobra and Green snakes as the most common. 88% of the people informed that working in the fields and forests was when most of the bites occur. A majority knew about snakebite prevention methods such as wearing long boots. However, only a few people knew about the specific symptoms caused by snakebites. Only 39% knew about the correct methods of first aid. More than 60% mentioned tourniquet as a first aid method, though this may cause significant complications such as ischaemia of the limb. 88% said that they would take a snakebite victim to a government hospital, and 58% mentioned availability of antivenom as the reason for doing this. At the same time, the majority mentioned that traditional methods existed for first aid and treatment and 25% mentioned at least one harmful traditional method as an effective measure that they might use.ConclusionThe community is aware of snakebites as a major public health issue and know how to prevent them. However, the high incidence of snakebites point to lack of application of preventive methods. The community recognise the need for treatment with antivenom. However, inadequate knowledge about appropriate first aid methods, and a reliance on using tourniquets require a targeted education program. Existing knowledge in communities, albeit insufficient, provides a good starting point for mass media educational campaigns.

Optimal wavelength for the clot waveform analysis: Determination of the best resolution with minimal interference of the reagents.

Clot waveform analysis (CWA), a new methodology to assess coagulation process, can be usefully applied in various clinical settings. However, its clinical use is limited mainly because of the absence of standardization. No consensus exists regarding the wavelengths at which CWA has to be performed what is crucial for the sensitivity of the CWA. The primary aim of this study is to determine which wavelength is the most sensitive and specific for CWA. Interindividual baseline absorbance will also be assessed as the impact of reagents from the intrinsic, extrinsic, and common coagulation pathway will be determined. Plasma samples were screened at wavelengths from 280 to 700nm to provide absorbance spectra in clotted and nonclotted plasma. The interindividual variability of baseline absorbance was obtained by screening plasma from 50 healthy individuals at 340, 635, and 671nm. The inner-filter effect of reagents was assessed in plasma or serum when appropriate at the same wavelengths. The reagents were those commonly used for activated partial thromboplastin time, prothrombin time, thrombin time, and dilute Russell's viper venom time. Clotted plasma has higher absorbance value than nonclotted plasma (P<0.01). The absorbance of all type of samples is higher at 340nm than at >600nm (P<0.01). The interindividual variability at the different wavelengths was around 25%. However, except with the STA®-CKPrest® and STA®-NeoPTimal®, the reagents do not have a significant effect on the baseline absorbance. Wavelengths above 650nm are recommended to perform CWA. Most of the commercialized reagents can be used for CWA.

A demonstration of variation in venom composition of Daboia russelii (Russell's viper), a significantly important snake of Myanmar, by tandem mass spectrometry

A demonstration of variation in venom composition of Daboia russelii (Russell's viper), a significantly important snake of Myanmar, by tandem mass spectrometry

Diagnosis of envenomation by Russell's and Echis carinatus viper: A clinical study at rural Maharashtra state of India.

Background:Envenoming by vipers Russell’s and Echis Carinatus are common accidents faced by farmers and labors. Both viper venom toxins alter coagulation mechanism in the victim. The dose of snake antivenin to neutralize the venom is empirical and varies. Though the clinical manifestations in both vipers bite envenoming are nearly similar but dose of antivenin required is more in Russell's viper. We studied in detail about the correlation of clinical manifestations and confirmed species of snake.Methods:Cases of vipers snake bites admitted for last two successive years were studied. Analysis by local manifestations, systemic involvement, 20 minute whole blood clotting test (20WBCT), identification of snake responsible for clinical effects are confirmed by the snake species brought by victims or bystanders, in case of where victim saw the snake bur failed to kill. The victims identified from pictures of big four poisonous snakes (Russell's viper, Echis carinatus, Cobra, and krait). Further confirmation from the species responsible is done by showing the hospital preserved specimen to identify the culprits.Findings:About 77 cases of viper bite studied of these 57 has clinical syndrome suggestive of Russell's viper (RV) bite, one has dry bite, 23 victims brought the killed specimen confirmed RV, of these 18 identified the specimen picture and 5 wrongly locate the species in pictures, 20 victims correctly identified the hospital preserved specimen while 3 failed to recognize. There were 28 patients who saw the snake while bitten but failed to kill, of these 20 patients identify correctly the species on picture while 8 failed to identify. Only 22 correctly identified the culprit by looking at the hospital preserved specimen and 6 were confused. One dry bite victim correctly identified the bitten snake species in picture and hospital preserved specimen.Interpretation:In viper bite poisoning clinical pictures and hospital specimen help to confirm the species are highly supportive for clinical diagnosis.

Clinico-epidemiology and management of Russell's viper (Daboia russelii) envenoming in dogs in Sri Lanka.

Russell's viper envenoming in dogs is a significant problem in Sri Lanka. The current study focused on investigating clinical profile, laboratory findings of three selected tests and to develop a treatment strategy with Indian polyvalent Anti-Venom Serum (AVS). It was also intended to report adverse effects and complications caused by both Russell's viper venom (RVV) and AVS in Russell's Viper (RV) envenomed dogs. To evaluate and report the clinical manifestations, to find out the minimum effective vials of AVS and to record AVS induced adverse reactions of RV envenoming in dogs. A prospective study was conducted on Russell's viper bitten dogs (n = 65) admitted to the Veterinary Teaching Hospital (VTH) in Sri Lanka. Indian polyvalent AVS was used to treat all the envenomed dogs. The number of vials of AVS that was administered to a patient was decided upon by a second degree polynomial model with a number of vials of AVS in the X axis verses Prothrombine Time (PT), Activated Partial Thromboplastine Time (aPTT) and Clotting Time (CT) in the Y axis respectively. Varying degrees of pain were exhibited by all the victim dogs. Mild swelling and necrosis at the site of bite was seen in 54% (n = 35) and 37% (n = 24) of dogs respectively. Prolonged values of, PT, aPTT and CT were seen from all the RV envenomed dogs. The mean leukocyte count in these dogs was 39.79 × 103/μL (normal range; 4-20 × 103/μL) (IQR:29.05 × 103/μL-45.92 × 103/μL). Statistical analysis showed that the initial vials of 7 AVS would be the minimum required vials. Therefore, a range of 6-15 AVS vials in total were administered to these dogs and in 7.6% (n = 5) of dogs, the results of PT, aPTT and CT became normal with 6 AVS vials at 32-97 minutes. Acute Renal Failure (ARF) was detected from 29% (n = 19) of dogs as a complication. Systemic clinical signs of haemorrhagic lesions, cardio respiratory toxicities were common in Russell's viper envenomed dogs. Initially 6 vials of AVS must be administered. AVS induced reactions were reported commonly. Russell's viper envenoming was found to be lethal in dogs.

Venomous snakebites: Management and anti-snake venom

In the Indian subcontinent, the “Big four” snakes of cobra, krait, Russell's viper, and saw-scaled viper are responsible for most of the venomous snakebites. Diagnosing envenomation is a pure clinical skill with no diagnostic kit available yet. Anti-snake venom (ASV) is a precious commodity, and clinicians across the country must be aware of the process of production of ASV so that they may use it judiciously for the treatment of envenomation.

Incidence and treatment of snakebites in West Bengal, India.

ObjectiveSnake envenomation is a major cause of death and disability in the developing countries. In India and neighboring countries, the four venomous snakes of concern include – Indian cobra(Naja naja), Common Krait (Bungarus caeruleus); Russell's Viper (Daboia russelli); Saw Scaled Viper (Echis carinatus). We describe the management protocol for snakebite treatment in a tertiary care hospital of Paschim Medinipur district, West Bengal based on case reports of subjects admitted and treated in Ghatal Subdivisional Hospital(GSH) during 2013–2016.Methods &materialsWe developed a structured data collection form to record demographic and clinical details of patients hospitalized at GSH between 1 January 2013 through 31 December 2016.ResultsSnake bite cases in Ghatal Subdivisional hospital(GSH) were assessed during the period 2013–2016. A total 18 deaths due to snakebite has been reported from this tertiary care hospital during the period. Total patients admitted in this hospital with snakebite is 1160 during the period 2013–2016. In 80% of the cases the lower extremities were affected. Preliminary first aid was provided in 45% cases. About 65% of the affected victims suffered snakebite in the morning hours. Some of the recommended drugs that were prescribed by the physicians of GSH were neostigmine, atropine, adrenaline, hydrocortisone, Amoxicillin. WBCT20 and Urea, Creatinine level were routinely performed.ConclusionHospital studies are a key source of information about snake bites. The ready availability and appropriate use of AVS, close monitoring of patients, the institution of ventilator support and if required, early referral to a larger hospital all help to reduce the mortality. Thus knowledge of the varied clinical manifestations of snake bite is important for effective management in hospitals by a complete health care team.

Snakebite Mitigation Project of the Madras Crocodile Bank/Centre for Herpetology, India: background and a brief summary of activities.

Snakebite is a serious problem in rural India where several highly venomous species are commonly found in and around agricultural areas where prey such as rodents and amphibians are abundant. Four snake species, referred to as the Big Four, are responsible for the most serious and fatal bites: spectacled cobra (Naja naja), Russell's viper (Daboia russelii), common krait (Bungarus caeruleus) and saw-scaled viper (Echis carinatus). A polyvalent antivenom is made to treat these bites but public awareness and distribution of this life-saving drug is inadequate. The Madras Crocodile Bank and its partners are conducting a snakebite project which includes venom sampling and research, snake and snakebite treatment centre mapping, and a nationwide awareness campaign for snakebite mitigation.

Twelve month prospective study of snakebite in a major teaching hospital in Mandalay, Myanmar; Myanmar Snakebite Project (MSP).

The Myanmar Snakebite Project is an Australian government (Department of Foreign Affairs and Trade) supported foreign aid project in collaboration with the Myanmar government with the aim of improving outcomes for snakebite patients in Myanmar. As part of the project a case record database was established to document prospective cases of snakebite presenting to Mandalay General Hospital, in Upper Myanmar. The study period was 12 months (1-2-2016 to 31-1-2017). Snake identity was based on a mixture of identified dead snakes brought with patients, doctor's clinical opinion and patient identification. 965 patients were enrolled during the 12 month period, of whom 948 were included for analysis. The male: female ratio was 1.58:1. Most cases involved bites to the lower limbs (82.5%) and adults involved in farm work, confirming snakebite as an occupational disease in this community. Motorised transport was by far the most common form of transport to health care and most patients sought care from the health system (87.7%), not traditional healers (11.5%) as their first point of contact. The officially promoted application of a pressure pad, bandage and immobilisation as first aid for snakebite was almost never used, while most patients used some form of tourniquet (92.0%). 85.4% of cases where a snake ID was listed were bitten by Russell's vipers. Russell's viper bites were responsible for all fatalities (9.8% of cases) and all cases of Acute Kidney Injury (AKI). For all cases, clinical features included local swelling (76.5%), local pain (62.6%), AKI (59.8%), incoagulable blood (57.9%), regional lymphadenopathy (39.8%), nausea/vomiting (40.4%), thrombocytopenia (53.6%), abdominal pain (28.8%), shock (11.8%), secondary infection (8.6%), panhypopituitarism (2.1%). AKI required renal replacement therapy (RRT) in 23.9% of cases, all ascribed to Russell's viper bite. Green pit viper bites were the next most common cause of bites (7.6%) and were associated with incoagulable blood (29%) and occasionally shock (5%) and local necrosis (3%), and in one case AKI not requiring RRT. In contrast to Russell's viper bites, green pit viper bite was most likely to occur in the home (49%). Some green pit viper patients were treated with Russell's viper antivenom (15%), presumably because they had incoagulable blood, although this antivenom is not effective against green pit viper envenoming. For the entire patient group, antivenom was given in 80.5% of cases. The most common indications were presence of coagulopathy/non-clotting blood (59.8%), local swelling (47.4%), oliguria/anuria (19.8%), heavy proteinuria (19.4%). A febrile reaction to antivenom was reported in 47.9% of cases, while anaphylaxis, occurred in 7.9% of cases.

Use of blood clotting assays to assess potential anticoagulant rodenticide exposure and effects in free-ranging birds of prey

Non-target wildlife, particularly birds of prey, are widely exposed to and acutely poisoned by anticoagulant rodenticides (ARs). An unresolved issue surrounding such exposure, however, is the potential for sublethal effects. In particular, the consequences of AR exposure and resulting coagulopathy on health and survival of unintentionally exposed animals, which often encounter a multitude of anthropogenic stressors, are understudied. In a wildlife rehabilitation setting, AR intoxication may be masked by more obvious injuries related to collision with vehicles or electrocution, thereby obfuscating proximate from ultimate cause of mortality. An assessment of coagulation function of admitted wildlife may provide a means of identifying animals exhibiting sublethal coagulopathy, and ultimately ensuring provision of appropriate and swift treatment. In conjunction with routine diagnostics for injury and disease, we performed two blood clotting assays (prothrombin time, Russell's viper venom time) affected by vitamin K-dependent coagulopathy of samples from six species of live raptors admitted to a rehabilitation facility. We also measured clotting time in pre-fledgling barn owl chicks (Tyto furcata) from 10 nest sites in Lower Mainland Canada. Prolonged clotting time or failure to form a clot altogether was observed in 23.0% of 61 sampled raptors admitted to the rehabilitation facility. This is a biologically significant proportion of individuals given the fortuitous and likely biased nature by which raptors are found and admitted to rehabilitation facilities. In contrast, there was little evidence of coagulopathy in 19 pre-fledgling barn owl chicks. The utility of avian coagulation tests for diagnosing AR exposure is promising, yet there remains a need to establish species specific reference values and standardize assay methodologies among testing facilities.

To Test or Not to Test? Quantifying and Reducing Inappropriate Hypercoagulable Workups in the Inpatient Setting

Background: Since the proposal of Virchow's Triad in 1856, the concept of hypercoagulability has been useful in analyzing causes of thromboembolic events. In the inpatient setting, evaluation of underlying causes of thrombosis is often complicated by unclear indications for testing, unreliability of individual assays, and confounding factors such as thrombosis itself and use of anticoagulant medications. We endeavored to quantify the occurrence of inappropriate hypercoagulable work-ups (HCW) in the inpatient setting in our institution, and then to implement a resident-focused educational intervention with the goal of limiting this unnecessary and potentially harmful use of resources.Methods: We retrospectively reviewed all patient charts containing an order for Factor V Leiden assay in 2017, 61 in total. If sufficient data were available, Hematology had not been consulted, and family history was not positive for thromboembolic events, orders were classified as inappropriate based on the recommendations of Pruthi1: temporary risk factors, active anticoagulation therapy, arterial thrombosis, or indefinite anticoagulation already indicated. We calculated the percentage of total charts with inappropriate orders. For our quality improvement intervention, we used a pre- and post-test design to assess knowledge before and after an educational presentation on HCW given to internal medicine and neurology residents. The pre- and post-tests were identical and consisted of 12 questions. SPSS statistical software was used to compare results using Chi-Square analysis. A p value <0.05 was considered significant.Results: A total of 37 charts were evaluated after exclusions, and 29 (78.4%) contained inappropriate orders for HCW. Of these, 16 (55.2%) were ordered as work-up of arterial thrombosis in patients with CVA or TIA but no cardiac shunt. 4 (13.8%) of the inappropriate orders followed provoked events. Apart from Factor V Leiden, additional assays were ordered with the following frequencies: Prothrombin gene mutation 92%, Anti-cardiolipin antibodies 78%, Homocysteine 43%, Antithrombin 42%, Protein C 42%, Protein S 42%, Anti-B-2-glycoprotein antibodies 25% and Dilute Russell's Viper Venom Test 22%. For our intervention, 85 resident tests were analyzed. An increase in correct responses occurred with statistical significance for questions regarding workup of CVA, as well as acute and chronic venous thrombosis. After the intervention, fewer residents stated that HCW would change their management of patients following a thromboembolic event (p<0.05). Residents correctly identified on pre-tests that anticoagulation would skew results of HCW. However, statistically significant improvement did occur in identifying appropriate timing of HCW between the pre- and post- test results (p<0.001).Conclusion: Thromboembolic events are commonly encountered in the inpatient setting, and often lead to inappropriate HCW, particularly in the setting of CVA and TIA without an intracardiac shunt. The set of assays ordered may also demonstrate high variability, which suggests uncertainty about which tests are most appropriate. HCW education in our resident population resulted in a statistically significant increase in correct responses to hypothetical clinical scenarios. This may predict decreased rates of inappropriate HCW, but further study with this endpoint would be beneficial. In addition, further interventions should be investigated, including hard stops and order sets in electronic health records. Through studies of this nature, which our data suggest are needed, unnecessary and potentially harmful use of resources could be reduced.1 Pruthi RK. Optimal utilization of thrombophilia testing. Int J Lab Hem. 2017;39(Suppl. 1):104-110. https://doi.org/10.1111/ijlh.12672 DisclosuresNo relevant conflicts of interest to declare.

Development of a Neural Network to Predict Thrombosis in the Antiphospholipid Syndrome with an Accuracy of 87%

Background: The antiphospholipid syndrome (APS) is characterized by the presence of antiphospholipid antibodies directed against β2-glycoprotein I (β2GPI) and/or cardiolipin. APS is associated with an increased risk of thrombosis and APS patients are known to have an altered thrombin generation (TG) profile. However, a single TG parameter cannot to differentiate between patients with or without a history of thrombosis.Therefore, we used a novel machine learning approach called ‘neural networking’ to search for hidden patterns in the clinical and experimental data of APS patients that identify patients with a high risk of thrombosis. In this method a neural network (NN) is trained using an existing dataset of APS patients. Training of the neural network ensures that it learns to classify samples (in this case patient with or without prior thrombosis) using the selected clinical and experimental database. Once the network has been trained and tested it can be used to differentiate between (new) APS patients with and without a history of thrombosis.Aim: To develop a neural network to predict thrombosis in APS patients based on their antibody profile and TG results.Materials and methods: Thirty-one non-anticoagulated APS patients (obstetric and thrombotic) were enrolled in the study after approval of the local ethics committee and after informed consent was obtained. Thrombosis had occurred in 21 APS patients either as arterial, venous or small vessel thrombosis. Thrombin generation was measured at 1 pM tissue factor (TF) and thrombin dynamics analysis was performed to study prothrombin conversion and thrombin inactivation. The sensitivity of the activated protein C system was tested by measuring TG in the presence and absence of 20 nM thrombomodulin (TM).The presence of aPL was defined as positivity for Lupus Anticoagulant and/or anticardiolipin (aCL) and/or β2GPI determined by enzyme linked immunosorbent assays (ELISA). LA was assessed according to the three-steps guidelines of the Subcommitee on LA of the International Society on Thrombosis and Haemostasis (ISTH) using Partial Thromboplastin Time - Lupus Anticoagulant (PTT-LA) and dilute Russel's Viper VenomTime (dRVVT) reagents.Multiple neural networks were trained and tested to predict whether a patient had a history of thrombosis using the Machine Learning Toolbox of Matlab. The input of the neural network consisted of the antibody profile and/or TG data (Figure 2).Results: The percentage of patients with antibodies against β2-glycoprotein I and cardiolipin did not differ between patients with and without prior thrombosis (Figure 1). Thrombin generation ETP (but not peak height) was significantly elevated in the thrombosis group. Due to overlap between the groups, it was not possible to distinguish between patients with and without a history of thrombosis (Figure 1).Two neural networks were trained (Figure 2): one based solely on the antibody profile of the patients and the other based on both the antibody profile and the TG results. The prediction accuracy of both neural networks was assessed in the testing phase of the NN development. The NN solely based on the antibody profile identified patients with a history of thrombosis with an accuracy of 82.2%. However, it was not capable of ruling out thrombosis in the non-thrombosis group (48.6% correctly classified vs. 51.4% incorrectly classified). The addition of the thrombin generation profile to the NN increased the prediction accuracy in the thrombosis group to 86.6%, but more interestingly, it also improved the capability of the NN to rule out thrombosis in the non-thrombosis group to 63.0%.Discussion:The development of thrombosis in APS is a complex process influenced by many factors, represented by alterations of various diagnostic variables, such as the antibody profile and the thrombin generation outcome. The presence of a certain antibody or the elevation of a single TG parameter was unable to predict thrombosis in APS. The integration of all data via neural networking circumvents this problem and can predict which patient had a prior thrombosis with an accuracy of 86.6% based on a combination of the antibody profile and thrombin generation parameters. The next step will be to test this approach in a prospective cohort of APS patients to develop a neural network to predict future thrombotic events in APS patients. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Implications of deranged activated partial thromboplastin time for anaesthesia and surgery.

Bleeding during and after surgery ranges from trivial to fatal. Bleeding is in part determined by the patient's coagulation status. The UK National Institute for Health and Care Excellence recommends a pre-operative clotting test for patients with a history of abnormal bleeding. Anaesthetists are familiar with the prothrombin time assay, used to monitor warfarin effect, but anaesthetists may be less familiar with the activated partial thromboplastin time (APTT), which tests the function of the 'intrinsic' clotting pathway. The activated partial thromboplastin time may be prolonged due to contamination, anticoagulant therapy, clotting factor deficiencies, lupus anticoagulant or acquired inhibitors of specific clotting factors. A prolonged activated partial thromboplastin time should lead to: further testing to exclude heparin contamination or therapy, mixing studies to identify factor deficiencies and if necessary dynamic studies, such as the dilute Russell's viper venom time and the Actin FS-activated partial thromboplastin time, to identify direct factor inhibitors. These tests identify abnormalities and their implications for bleeding, helping anaesthetists and haematologists to manage haemostasis for individual patients.

Paired APTTs of low and high lupus anticoagulant sensitivity permit distinction from other abnormalities and achieve good lupus anticoagulant detection rates in conjunction with dRVVT

A prolonged activated partial thromboplastin time (APTT) may be indicative of a specific or multiple factor deficiency, therapeutic anticoagulation, presence of a nonspecific factor inhibitor, or lupus anticoagulant (LA). Recently, pairing of the LA-sensitive APTT and standard APTT reagents, Cephen LS and Cephen, respectively, has been shown to be effective in LA detection. The present study aimed to evaluate the usefulness of this reagent pair for discriminating between causes of APTT elevation and the detection of LA in conjunction with dilute Russell's viper venom time (dRVVT). Plasma samples from 50 normal and 105 non-anticoagulated LA-positive patients in routine dRVVT and/or dilute APTT (dAPTT) via the percent correction formula were employed. Cephen LS/Cephen and dRVVT reagents LA1/LA2 were used to screen/confirm, respectively. Thirty-four symptomatic LA-negative, 25 warfarinised non-antiphospholipid syndrome, 6 coagulation inhibitors, 17 samples with hereditary elevated APTT, and 24 FVIII/IX/XI/XII and 17 FII/V/X artificial single deficiency plasmas were used. Thirty-three samples out of 105 (31%) were LA-positive in Cephen LS/Cephen. The total percent positivity in Cephen LS/Cephen and LA1/LA2 pairs was 89.1% against samples with the routine dRVVT/dAPTT double positive. The percent corrections of Cephen LS/Cephen in the routine dAPTT/dRVVT positive group were significantly higher than those in all other groups. The percent correction of the APTT reagent pair showed higher values in LA-positive samples. The combination will be useful with respect to differentiating LA from other abnormal samples and is effective in LA detection when paired with dRVVT.

Determination of the sub-lethal nephrotoxic dose of Russell's viper (Daboia russelii) venom in Wistar rats

Wistar rats were administered increasing doses of Russell's viper venom (RVV; 0.025–0.4 mg/kg) intraperitoneally to investigate acute kidney injury (AKI) by measuring creatinine (1.5-fold increase in serum creatinine above baseline) and examining kidney histology. Approximately 50% of rats receiving 0.25–0.4 mg/kg venom died within 72 h. An increase in serum creatinine only occurred at a venom dose of 0.4 mg/kg, except in two rats. Acute tubular necrosis, glomerular necrosis, cortical necrosis and interstitial inflammation were observed at venom doses of ≥0.25 mg/kg in 12/36 rats. However, of those 12 rats only four survived to 48 h compared to the 24 rats not developing nephrotoxicity, in which 18 were alive at 48 h. There was poor correlation between histological nephrotoxicity and AKI based on creatinine measurement. The early death in rats with AKI makes this a poor model for studying RVV-induced AKI.