Displaying publications 101 - 120 of 197 in total

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  1. Incidence, clinical manifestation and general management of snake bites
    Trishnananda M
    Southeast Asian J Trop Med Public Health, 1979 Jun;10(2):248-50.
    PMID: 524149
    There are regional patterns in snake-bites. Bites by cobras have a high incidence in Thailand and in the Philippines with a high case fatality rate. Among the venomous snakes of haemorrhagic nature, bites by Trimeresurus species such as green pit viper, Taiwan habu and Taiwan bamboo viper are important in Thailand and Taiwan for their high incidence of bite, although the case fatality rates are low. Bites by Malayan pit vipers are also important in Thailand and Malaysia because of their high incidence. Bites by sea snakes are more common in Malaysia than in the Philippines and Thailand.
    Matched MeSH terms: Snake Venoms
  2. Fulltext A Rare Infection Following Snakebite
    Cheong, C.Y., Lee, C.K., Zuki Z.
    Malays Orthop J, 2010;4(1):-.
    MyJurnal
    Snakebite is very common especially in Asia. We report a rare case of Providencia rettgeri infection following snakebite on the foot. This patient was treated with early and aggressive wound debridement, daily wound dressing during hospitalization and then skin coverage with split skin graft. No anti-venom was given administered. Appropriate intravenous antibiotics were given to the patient while hospitalized and oral antibiotic were prescribed upon discharge. The outcome of this treatment was successful.
    Matched MeSH terms: Venoms
  3. Cross neutralisation of Southeast Asian cobra and krait venoms by Indian polyvalent antivenoms
    Leong PK, Tan NH, Fung SY, Sim SM
    Trans R Soc Trop Med Hyg, 2012 Dec;106(12):731-7.
    PMID: 23062608 DOI: 10.1016/j.trstmh.2012.07.009
    Cross neutralisation of venoms by antivenom raised against closely-related species has been well documented. The spectrum of paraspecific protection of antivenom raised against Asiatic Naja and Bungarus (krait) venoms, however, has not been fully investigated. In this study, we examined the cross neutralisation of venoms from common Southeast Asian cobras and kraits by two widely used polyvalent antivenoms produced in India: Vins Polyvalent Antivenom (VPAV) and Bharat Polyvalent Antivenom (BPAV), using both in vitro and in vivo mouse protection assays. BPAV was only moderately effective against venoms of N. kaouthia (Thailand) and N. sumatrana, and either very weakly effective or totally ineffective against the other cobra and krait venoms. VPAV, on the other hand, neutralised effectively all the Southeast Asian Naja venoms tested, as well as N. naja, B. candidus and Ophiophagus hannah venoms, but the potency ranges from effective to weakly effective. In an in vivo rodent model, VPAV also neutralised the lethality of venoms from Asiatic Naja and B. candidus. In anesthetised rat studies, both antivenoms effectively protected against the N. kaouthia venom-induced cardio-respiratory depressant and neuromuscular blocking effects. Overall, our results suggest that VPAV could be used as alternative antivenom for the treatment of elapid envenomation in Southeast Asian regions including Malaysia, Thailand and certain regions of Indonesia.
    Matched MeSH terms: Elapid Venoms/antagonists & inhibitors*; Elapid Venoms/immunology; Elapid Venoms/toxicity
  4. Fulltext Effect of Mucuna pruriens Seed Extract Pretreatment on the Responses of Spontaneously Beating Rat Atria and Aortic Ring to Naja sputatrix (Javan Spitting Cobra) Venom
    Fung SY, Tan NH, Sim SM, Aguiyi JC
    Evid Based Complement Alternat Med, 2012;2012:486390.
    PMID: 21785646 DOI: 10.1155/2012/486390
    Mucuna pruriens Linn. (velvet bean) has been used by native Nigerians as a prophylactic for snakebite. Rats pretreated with M. pruriens seed extract (MPE) have been shown to protect against the lethal and cardiovascular depressant effects of Naja sputatrix (Javan spitting cobra) venoms, and the protective effect involved immunological neutralization of the venom toxins. To investigate further the mechanism of the protective effect of MPE pretreatment against cobra venom toxicity, the actions of Naja sputatrix venom on spontaneously beating rat atria and aortic rings isolated from both MPE pretreated and untreated rats were studied. Our results showed that the MPE pretreatment conferred protection against cobra venom-induced depression of atrial contractility and atrial rate in the isolated atrial preparations, but it had no effect on the venom-induced contractile response of aortic ring preparation. These observations suggested that the protective effect of MPE pretreatment against cobra venom toxicity involves a direct protective action of MPE on the heart function, in addition to the known immunological neutralization mechanism, and that the protective effect does not involve action on blood vessel contraction. The results also suggest that M. pruriens seed may contain novel cardioprotective agent with potential therapeutic value.
    Matched MeSH terms: Elapid Venoms
  5. Isolation and characterization of α-elapitoxin-Bf1b, a postsynaptic neurotoxin from Malaysian Bungarus fasciatus venom
    Rusmili MR, Tee TY, Mustafa MR, Othman I, Hodgson WC
    Biochem Pharmacol, 2014 Mar 15;88(2):229-36.
    PMID: 24440452 DOI: 10.1016/j.bcp.2014.01.004
    Bungarus fasciatus is one of three species of krait found in Malaysia. Envenoming by B. fasciatus results in neurotoxicity due to the presence of presynaptic and postsynaptic neurotoxins. Antivenom, either monovalent or polyvalent, is the treatment of choice in systemically envenomed patients. In this study, we have isolated a postsynaptic neurotoxin which we named α-elapitoxin-Bf1b. This toxin has an approximate molecular weight of 6.9 kDa, with LCMS/MS data showing that it is highly homologous with Neurotoxin 3FTx-RI, a toxin identified in the Bungarus fasciatus venom gland transcriptome. α-Elapitoxin-Bf1b also shared similarity with short-chain neurotoxins from Laticauda colubrina and Pseudechis australis. α-Elapitoxin-Bf1b produced concentration- and time-dependent neurotoxicity in the indirectly-stimulated chick biventer cervicis muscle preparation, an effect partially reversible by repetitive washing of the preparation. The pA2 value for α-elapitoxin-Bf1b of 9.17 ± 0.64, determined by examining the effects of the toxin on cumulative carbacol concentration-response curves, indicated that the toxin is more potent than tubocurarine and α-bungarotoxin. Pre-incubation of Bungarus fasciatus monovalent and neuro polyvalent antivenom failed to prevent the neurotoxic effects of α-elapitoxin-Bf1b in the chick biventer cervicis muscle preparation. In conclusion, the isolation of a postsynaptic neurotoxin that cannot be neutralized by either monovalent and polyvalent antivenoms may indicate the presence of isoforms of postsynaptic neurotoxins in Malaysian B. fasciatus venom.
    Matched MeSH terms: Elapid Venoms/genetics; Elapid Venoms/isolation & purification; Elapid Venoms/toxicity
  6. A case of fatal envenomation by a captive puff adder (Bitis arietans) in Malaysia
    Husain Z, Wicaksono AC, Renault A, Md Zhahir SS, Ismail AK
    Toxicon, 2023 Mar 01;224:107023.
    PMID: 36640813 DOI: 10.1016/j.toxicon.2023.107023
    The Puff Adder (Bitis arietans) is a viper native to Africa and the Middle East. Envenomation by this species often requires the administration of appropriate antivenom in order to achieve a favorable outcome. A patient was bitten in both hands by a captive B. arietans presented to a teaching hospital in Malaysia. The patient developed painful progressive swelling on both limbs that extended to the chest, hypotension, hypokalemia with worsening anemia, thrombocytopenia, coagulopathy, and severe metabolic acidosis. The patient was managed supportively while waiting for the appropriate antivenom, Antivipmyn-Africa, from the Singapore Zoo. The patient developed cardiorespiratory arrest twice and did not recover from the second. The patient was pronounced dead 23 hours post-incident. The local unavailability of the appropriate antivenom may be the most important factor that contributed to the patient's death. There is also a need to amend the Malaysian Wildlife Act in order to prevent such cases from recurring.
    Matched MeSH terms: Viper Venoms
  7. Cross reactivity and lethality neutralization of venoms of Indonesian Trimeresurus complex species by Thai Green Pit Viper Antivenom
    Tan CH, Liew JL, Tan NH, Ismail AK, Maharani T, Khomvilai S, et al.
    Toxicon, 2017 Dec 15;140:32-37.
    PMID: 29051104 DOI: 10.1016/j.toxicon.2017.10.014
    Arboreal pit vipers of the Trimeresurus complex group are medically important species in Indonesia (west of Wallace's line), but there is no specific antivenom produced in the country for treating related envenomation. Instead, the exiting trivalent Indonesian antivenom, Biosave® Serum Anti Bisa Ular (SABU, indicated for envenoming by Malayan pit viper, Javan spitting cobra and banded krait) is often misused to treat Trimeresus envenoming resulting in poor therapeutic outcome. Here, we investigated the cross-reactivity and neutralization capability of Thai Green Pit Viper Antivenom (GPVAV) against the venoms of four Indonesian Trimeresurus species. Consistently, the venoms of Trimeresurus (Trimeresurus) insularis, Trimeresurus (Trimeresurus) purpureomaculatus, Trimeresurus (Parias) hageni and Trimeresurus (Craspedocephalus) puniceus of Indonesia showed stronger immunoreactivity on ELISA to GPVAV than to Biosave®. The findings correlated with in vivo neutralization results, whereby GPVAV was far more effective than Biosave® in cross-neutralizing the lethality of the venoms by a potency of at least 13 to 80 times higher. The efficacy of GPVAV is partly attributable to its cross-neutralization of the procoagulant effect of the venoms, thereby mitigating the progression of venom-induced consumptive coagulopathy. The paraspecific effectiveness of GPVAV against Trimeresurus species envenoming in Indonesia await further clinical investigation.
    Matched MeSH terms: Crotalid Venoms/immunology*
  8. Venom proteome of the yellow-lipped sea krait, Laticauda colubrina from Bali: Insights into subvenomic diversity, venom antigenicity and cross-neutralization by antivenom
    Tan CH, Wong KY, Tan KY, Tan NH
    J Proteomics, 2017 08 23;166:48-58.
    PMID: 28688916 DOI: 10.1016/j.jprot.2017.07.002
    The venom proteome of Laticauda colubrina (Bali, Indonesia) was elucidated by nano-ESI-LCMS/MS of the venom reverse-phase HPLC fractions. Altogether 31 distinct forms of proteins were identified and clustered into three toxin families: three-finger toxin (3FTX, 66.12% of total venom proteins), phospholipase A2 (PLA2, 33.26%) and cysteine-rich secretory protein (CRiSP, 0.05%). The 3FTX were α-neurotoxins (five long neurotoxins, LNTX, 48.87%; two short neurotoxins, SNTX, 16.94%) and a trace amount of two cytotoxins (CTX, 0.31%). PLA2 were present with a large diversity of homologues (≥20 forms), however none was annotated to the lethal proteoform reported previously. The venom is highly lethal in mice (LD50=0.10μg/g) and this is driven primarily by the SNTX and LNTX (LD50=0.05-0.13μg/g), since the PLA2 proteins were non-lethal up to 2μg/g (20-time the venom LD50). The SNTX and LNTX were effectively cross-neutralized by the heterologous Sea Snake Antivenom (SSAV, Australian product) (potency=0.27mg toxin per ml antivenom, and 0.40mg/ml, respectively), corroborating the cross-neutralization of the whole venom (potency=1.09mg/ml) and its antigenic immunoreactivity toward SSAV. Furthermore, compared with earlier studies, the present work reveals geographical variation of venom composition for L. colubrina which may have implication for the evolution and conservation of the species.

    BIOLOGICAL SIGNIFICANCE: Laticauda colubrina (yellow-lipped sea krait) is a widely distributed, semi-aquatic venomous snake species. The venom proteome at the level of protein family is unsophisticated and consistent with its restricted prey selection. Nonetheless, the subproteomic findings revealed geographical variability of the venom for this widely distributed species. In contrast to two previous reports, the results for the Balinese L. colubrina venom showed that LNTX Neurotoxin a and Neurotoxin b were co-existent while the PLA2 lethal subtype (PLA-II) was undetected by means of LCMS/MS and by in vivo assay. This is an observable trait of L. colubrina considered divergent from specimens previously studied for the Philippines and the Solomon Islands. The stark geographical variation might be reflective of trophic adaptation following evolutionary arms race between the snake and the prey (eels) in different localities. The preferred trait would likely propagate and remain significant within the geographical population, since the strong behaviour of site fidelity in the species would have minimized gene flow between distant populations. Meanwhile, the in vivo neutralization study verified that the efficacy of the heterologous Sea Snake Antivenom (Australian product) is attributable to the cross-neutralization of SNTX and LNTX, two principal lethal toxins that made up the bulk of L. colubrina venom proteins. The findings also implied that L. colubrina, though could be evolutionarily more related to the terrestrial elapids, has evolved a much streamlined, neurotoxin- and PLA2-predominated venom arsenal, with major antigenicity shared among the true sea snakes and the Australo-Papuan elapids. The findings enrich our current understanding of the complexity of L. colubrina venom and the neutralizing spectrum of antivenom against the principal toxins from this unique elapid lineage.

    Matched MeSH terms: Elapid Venoms/immunology*
  9. Evaluating the physicochemical properties and efficacy of recently expired and aged antivenom products from Thailand and Taiwan
    Tan KY, Liew ST, Tan QY, Abdul-Rahman FN, Azmi NI, Sim SM, et al.
    Toxicon, 2019 Mar 15;160:55-58.
    PMID: 30797900 DOI: 10.1016/j.toxicon.2019.02.010
    Gel filtration chromatography and gel electrophoresis revealed minimal protein degradation in lyophilized antivenoms which were 2-year expired (Hemato Polyvalent, Neuro Polyvalent; Thailand) and 18-year expired (Hemato Bivalent, Neuro Bivalent; Taiwan). All expired antivenoms retained immunological binding activity, and were able to neutralize the hemotoxic or neurotoxic as well as lethal effects of the homologous snake venoms. The findings show that antivenoms under proper storage conditions may remain relatively stable beyond the indicated shelf life.
    Matched MeSH terms: Snake Venoms/antagonists & inhibitors
  10. Thai Russell's viper monospecific antivenom is immunoreactive and effective in neutralizing the venom of Daboia siamensis from Java, Indonesia
    Lingam TMC, Tan KY, Tan CH
    Toxicon, 2019 Oct;168:95-97.
    PMID: 31254600 DOI: 10.1016/j.toxicon.2019.06.227
    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.
    Matched MeSH terms: Viper Venoms/toxicity*
  11. Proteolytic specificity of rhodostoxin, the major hemorrhagin of Calloselasma rhodostoma (Malayan pit viper) venom
    Tan NH, Ponnudurai G, Chung MC
    Toxicon, 1997 Jun;35(6):979-84.
    PMID: 9241791
    The proteolytic specificity of rhodostoxin, the major hemorrhagin from Calloselasma rhodostoma (Malayan pit viper) venom was investigated using oxidized B-chain of bovine insulin as substrate. Six peptide bonds were cleaved: Ser9-Hist10, His10-Leu11, Ala14-Leu15, Tyr16-Leu17, Gly20-Glu21 and Phe24-Phe25. Deglycosylated rhodostoxin, however, cleaved primarily at Arg22-Gly23.
    Matched MeSH terms: Crotalid Venoms/metabolism*
  12. Gambir, "Gambir Sarawak" and toad venom
    Lim WJ, Yap AT, Mangudi M, Hu CY, Yeo CY, Eyo ZW, et al.
    Drug Test Anal, 2017 Mar;9(3):491-499.
    PMID: 27367276 DOI: 10.1002/dta.2034
    Matched MeSH terms: Amphibian Venoms/chemistry*
  13. Isolation and characterization of an acidic lethal phospholipase Az from Malayan cobra (Naja naja sputatrix) venom
    Tan NH, Arunmozhiarasi A
    Biochem. Int., 1989 Apr;18(4):785-92.
    PMID: 2764979
    An acidic, lethal phospholipase Az was purified to electrophoretic homogeneity from the venom of the Malayan cobra (Naja naja sputatrix). The enzyme has an isoelectric point of 5.58, a molecular weight of 12000, and a medium lethal dose (LD50) of 0.86 micrograms/g in mice by intravenous injection. The enzyme also exhibited weak anticoagulant and edema-forming activities. The amino acid composition of the enzyme is similar to those of other cobra venom phospholipases Az.
    Matched MeSH terms: Cobra Venoms/analysis*
  14. Substrate specificity of king cobra (Ophiophagus hannah) venom L-amino acid oxidase
    Tan NH, Saifuddin MN
    Int. J. Biochem., 1991;23(3):323-7.
    PMID: 2044840
    1. Substrate specificity of purified king cobra (Ophiophagus hannah) venom L-amino acid oxidase was investigated. 2. The enzyme was highly specific for the L-enantiomer of amino acid. Effective oxidation of L-amino acid by the enzyme requires the presence of a free primary alpha-amino group but the alpha-carboxylate group is not as critical for the catalysis. 3. The enzyme was very active against L-Lys, L-Phe, L-Leu, L-Tyr, L-Tryp, L-Arg, L-Met, L-ornithine, L-norleucine and L-norvaline and moderately active against L-His, L-cystine and L-Ileu. Other L-amino acids were oxidized slowly or not oxidized. 4. The data suggest the presence of a side chain binding site in the enzyme, and that the binding site comprises at least five 'subsites': the hydrophobic subsites a, b and c; and the two 'amino' binding subsites d and e. Subsite b appears to be able to accommodate two methylene/methyl carbons.
    Matched MeSH terms: Elapid Venoms/analysis*
  15. The use of enzyme-linked immunosorbent assay for the quantitation of Calloselasma rhodostoma (Malayan pit viper) venom and venom antibodies
    Tan NH, Yeo KH, Jaafar MI
    Toxicon, 1992 Dec;30(12):1609-20.
    PMID: 1488770
    The specificity and sensitivity of an indirect and two (an 'ordinary' and a 'rapid') double sandwich enzyme-linked immunosorbent assay (ELISA) procedures for the quantitation of Calloselasma rhodostoma (Malayan pit viper) venom were examined. The three assays were equally sensitive and the accuracy of the assays was not substantially affected by individual variation in the venom composition. The specificity of the assays was examined against 26 venoms from snakes of the families Viperidae and Elapidae. While the double sandwich ELISA procedures were sufficiently specific to be used in the clinical immunodiagnosis of C. rhodostoma bite in Malaysia, the indirect ELISA procedure exhibited extensive cross-reactivity with other Malaysian pit viper venoms. Attempts were made to improve the specificity of the indirect ELISA procedure for the quantitation of C. rhodostoma venom. A 'low ELISA cross-reactivity' venom fraction (termed VF52) was isolated from C. rhodostoma venom by repeated Sephadex G-100 gel filtration chromatography. The indirect ELISA procedure using antibodies to VF52 as immunoreagent showed an improvement in specificity. The use of the indirect ELISA procedure for the detection of C. rhodostoma antibodies was also examined and the results show that the assay was sufficiently specific to be used for retrospective diagnosis of C. rhodostoma bite in Malaysia, in particular when VF52 was used as the coating antigen.
    Matched MeSH terms: Viper Venoms/analysis*
  16. Purification and properties of the L-amino acid oxidase from monocellate cobra (Naja naja kaouthia) venom
    Tan NH, Swaminathan S
    Int. J. Biochem., 1992 Jun;24(6):967-73.
    PMID: 1612186
    1. The L-amino acid oxidase of the monocellate cobra (Naja naja kaouthia) venom was purified to electrophoretic homogeneity. The molecular weight of the enzyme was 112,200 as determined by Sephadex G-200 gel filtration chromatography, and 57,400 as determined by SDS-polyacrylamide gel electrophoresis. 2. The enzyme had an isoelectric point of 8.12 and a pH optimum of 8.5. It showed remarkable thermal stability, and, unlike many venom L-amino acid oxidase, was also stable in alkaline medium. The enzyme was partially inactivated by freezing. 3. The enzyme was very active against L-phenylalanine and L-tyrosine, moderately active against L-tryptophan, L-methionine, L-leucine, L-norleucine, L-arginine and L-norvaline. Other L-amino acids were oxidized slowly or not oxidized. 4. Kinetic studies suggest the presence of a side-chain binding site in the enzyme, and that the binding site comprises of at least four hydrophobic subsites.
    Matched MeSH terms: Cobra Venoms/enzymology*
  17. Isolation and characterization of a hemorrhagin from the venom of Ophiophagus hannah (king cobra)
    Tan NH, Saifuddin MN
    Toxicon, 1990;28(4):385-92.
    PMID: 2190359
    The major hemorrhagin (termed hannahtoxin) of the venom of Ophiophagus hannah (king cobra) was purified to electrophoretic homogeneity by DEAE-Sephacel ion exchange chromatography, Sephadex G-200 gel filtration followed by a second DEAE-Sephacel chromatography. Proteolytic activity was associated with the hemorrhagic activity throughout the purification procedures. Hannahtoxin constituted approximately 2% of the crude venom. It had an isoelectric point of 5.3, a carbohydrate content of 12%, a mol. wt of 66,000 as determined by SDS-polyacrylamide gel electrophoresis and 63,000 as determined by gel filtration. It contains 1 mole of Zn per mole of protein. The minimum hemorrhage doses for hannahtoxin are 0.7 microgram and 75 micrograms, respectively, in rabbits and in mice. Hannahtoxin was not lethal to mice at a dose of 2 mg/kg (i.v.) but killed rabbits at doses above 0.18 mg/kg (i.v.). It liberated protein from rabbit glomerular basement membrane but not rat glomerular basement membrane. Treatment of the hemorrhagin with EDTA and 1,10-phenanthroline eliminated both the proteolytic and hemorrhagic activities completely.
    Matched MeSH terms: Elapid Venoms/analysis*
  18. Acidimetric assay for phospholipase A using egg yolk suspension as substrate
    Tan NH, Tan CS
    Anal Biochem, 1988 May 1;170(2):282-8.
    PMID: 3394929
    A convenient acidimetric assay for phospholipase A using egg yolk suspension as substrate has been developed. The substrate mixture consists of 1 part egg yolk, 1 part 8.1 mM sodium deoxycholate, and 1 part 18 mM calcium chloride. Phospholipase A activity is measured by following the initial rate of pH change, which is linear between pH 8.0 and 7.75 and is proportional to enzyme concentration over a wide range. The assay is highly reproducible, with a coefficient of variation of 3%, and as sensitive as most established assays for phospholipase A. The assay uses inexpensive and easily available substrate and is simple to perform. It is particularly useful for monitoring phospholipase A activity in chromatography fractions.
    Matched MeSH terms: Cobra Venoms/analysis
  19. Bleeding after Malayan pit viper bites
    Chan KE
    Southeast Asian J Trop Med Public Health, 1979 Jun;10(2):276-9.
    PMID: 524154
    Matched MeSH terms: Crotalid Venoms/pharmacology
  20. Assessing the role of anti-viper serum in the management of viper bites
    Singh N, Menon V
    Med J Malaysia, 1973 Sep;28(1):47-9.
    PMID: 4273785
    Matched MeSH terms: Venoms/poisoning*
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