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PubMed1987

Detection of venom by enzyme linked immunosorbent assay (ELISA) in patients bitten by snakes in Thailand.

The ability of an enzyme linked immunosorbent assay (ELISA) to detect venom was evaluated in 251 patients bitten by four of the commonest poisonous snakes in Thailand. Serum was tested only from patients who brought the snakes that had bitten them. About one third of all bitten patients had detectable venom antigenaemia, though a smaller proportion were symptomatic. Serum venom concentrations on admission correlated with the severity of clinical manifestations. The test was sensitive and specific even for specimens that had been collected and stored under suboptimal conditions. The technique is suitable for forensic use in cases of suspected snakebite. The combination of snake identification and venom antigen detection should be a more reliable means of studying the epidemiology of snakebite than the measurement of venom antibodies in a population.

Adolescent↗

PubMed1982

Envenomation by a King Island tiger snake (Notechis ater humphreysi).

A venomous King Island tiger snake (Notechis ater humphreysi)bit a herpetologist on the hand on the forty-eight floor of a Sydney city building. Prompt first-aid treatment, comprising the application of a wide constrictive bandage the length of the limb, combined with immobilisation, delayed central movement of the venom until resuscitative care and antivenom were available. The patient had received tiger-snake antivenom 16 years previously, and also suffered from atopic eczema. Administration of 6000 units of tiger-snake antivenom after parenteral administration of an antihistamine was uneventful. A transient rash on the second day and a mild urticarial rash on the twelfth day after envenomation may have been either serum reactions or allergic response to other medication.

Adult↗

PubMed1993

Fatal brown snake (Pseudonaja textilis) envenomation despite the use of antivenom.

OBJECTIVE: To report two cases of fatal brown snake envenomation in adults despite the use of appropriate antivenom. CLINICAL FEATURES: Two men, aged 42 and 39, one with a history of hypertension, suffered fatal brown snake envenomation in Queensland. One believed he had been stung by a wasp. Both developed cardiorespiratory failure within one hour of the bite, followed by coagulopathy and pulmonary oedema. One patient developed fulminant multiorgan failure. INTERVENTION: Both patients died despite the administration of large doses of appropriate antivenom and full supportive care. CONCLUSION: Brown snake bites remain extremely dangerous despite the availability of specific antivenom. In severe cases associated with myocardial depression and gross coagulopathy, death may occur rapidly despite the use of conventional doses of antivenom. In such patients the antivenom requirement may be much greater than is currently recommended.

Adult↗

PubMed2002

[Understanding snake venoms: 50 years of research in Latin America].

As a tribute to Revista de Biología Tropical in its 50th anniversary, this review describes some of the main research efforts carried out in the study of the chemical composition and the mechanism of action of toxins present in the venoms of snakes distributed in Latin America. Venom proteins involved in neurotoxicity, coagulopathies, hemorrhage and muscle necrosis are discussed, together with a description of the inflammatory reactions elicited by these venoms and toxins. In addition, the search for inhibitory substances present in plants and animals that may be utilized in the neutralization of venoms is analyzed. Some of the clinical studies performed on snakebite envenomations in Latin America are also reviewed, together with the development of technologies aimed at improving the quality of antivenoms produced in the region. Toxinology has become a fruitful and stimulating research field in Latin America which has contributed to a better understanding of snake venoms as well as to an improved management of snake bitten patients.

Antivenins↗

PubMed2002

[The snakes of Senegal: an annotated species list].

Between 1990 and 2001, the laboratory of Paludologie of IRD at Dakar collected over 5,500 snakes from all over Senegal. By studying this collection, an entirely new species was discovered for science and eight new species for Senegal. The presence of many specimens of rare species and the great number of localities from which snakes were collected also allowed us to solve several delicate taxonomic problems and better to specify the biogeography of Senegalese snakes. Currently, the presence in Senegal of at least 55 different species has been established with certainty. The data collected simultaneously on the burden of snakebites for public health shows considerable differences according to geographic area, with populations from south-eastern Senegal being more exposed to the risk of death by snakebite.

Animals↗

PubMed2003

[Clinical observation on treatment of snake bite induced disseminated intravascular coagulation by qinwen baidu decoction].

OBJECTIVE: To observe the effect of Qinwen Baidu Decoction (QBD) in treating snake bite induced dissseminated intravascular coagulation (DIC). METHODS: Forty-six patients were randomly divided into the control group (n = 16) and the treated group (n = 30). They were all treated with the conventional therapy, including application of anti-snake venom serum and supplement of blood agglutination factors. For the treated group, QBD was administered additionally. The efficacy of treatment, chief indexes for DIC (platelet, fibrinogen and prothrombin time) and their recovery time, etc. were observed. RESULTS: The total effective rate of the treated group was 93.33%, which was higher than that of the control group (56.35%), and the recovery time of chief DIC indexes in the treated group was significantly shorter than that in the control group respectively (P < 0.01). CONCLUSION: QBD shows obvious effects of shortening therapeutic course and enhancing efficacy in treating snake bite induced DIC.

Adolescent↗

PubMed2005

Bilateral angle closure glaucoma following snake bite.

Snake venoms are complex heterogenous poisons with multiple effects. Ocular complications with snake bite are rare. This report describes two cases which developed bilateral acute angle closure glaucoma following snake bite. There was complete recovery in the two patients following timely diagnosis and treatment.

Adult↗

PubMed1996

[Envenomation by exotic snakes].

Snake bite envenoming in tropical areas affects an estimated one million people according to the World Health Organization. Two studies showed that annual mortality is between 30,000 and 50,000 people. Clinically cobra and viper envenoming are the most well known but several other snakes cause characteristic manifestations allowing species-specific diagnosis. Immuno-enzymatic tests are a useful diagnostic tool that is currently expanding but remains available only in developing countries because of cost. Treatment consists mainly of serotherapy in the most severe cases. Use of purified products and fragments active specifically on toxins and enzymes is both safer and more effective. Heparinotherapy should be used only when indicated by clinical manifestations and hemostasis testing. Management of envenoming must be organized in function of antivenom availabilities in a given region. Future improvements in immuno-enzymatic tests and antivenoms should allow more successful treatment of severe snake bite envenoming.

Animals↗

PubMed1998

Liver microsomes from the yellow rat snake (Elaphe obsoleta) and American bullfrog (Rana catesbeiana) oxidize polyunsaturated fatty acids by NADPH-dependent hydroxylation and epoxidation.

Polyunsaturated fatty acids (PUFAs) can be oxygenated by mammalian hepatic P450s to a series of metabolites. The most prominent of these are formed by omega- and (omega-1)-hydroxylation, epoxidation of the double bonds or bisallylic hydroxylation. The object of the present investigation was to determine whether similar oxygenations are catalyzed by liver microsomes of the yellow rat snake (Elaphe obsoleta) and the American bullfrog (Rana catesbeiana). Liver microsomes were incubated with [1-14C]-labeled arachidonic (AA), eicosapentaenoic (EPA), and linoleic acids (LA) in the presence or absence of 1 mM NADPH, and the major metabolites were analyzed by reverse-phase and straight-phase high performance liquid chromatography and capillary gas chromatography-mass spectroscopy. No metabolites were produced in the absence of NADPH. Profiles of metabolites were different depending on the organism and the acclimation state. In all incubations, EPA was the most effective substrate utilized and LA the least effective. The major products from EPA were 19-HEPE, 13-HEPE, and 20-HEPE from cold-acclimated (5 degrees C), warm-acclimated (22 degrees C) frogs, and snakes (22 degrees C), respectively. In contrast, 20-HETE production from AA was greater than 19-HETE in all three. Cold-acclimated frog liver microsomes produced significantly more of all metabolites when compared with microsomes from warm-acclimated frogs. We conclude that amphibian and snake liver can catalyze epoxidation and hydroxylation of PUFAs and that products are species-specific and acclimation-state dependent.

Acclimatization↗

PubMed2000

Ultrastructure of the reproductive system of the black swamp snake (Seminatrix pygaea). II. Annual oviducal cycle.

This article is the first ultrastructural study on the annual oviducal cycle in a snake. The ultrastructure of the oviduct was studied in 21 females of the viviparous natricine snake Seminatrix pygaea. Specimens were collected and sacrificed in March, May, June, July, and October from one locale in South Carolina during 1998-1999. The sample included individuals: 1) in an inactive reproductive condition, 2) mated but prior to ovulation, and 3) from early and late periods of gravidity. The oviduct possesses four distinct regions from cranial to caudal: the anterior infundibulum, the posterior infundibulum containing sperm storage tubules (SSTs), the uterus, and the vagina. The epithelium is simple throughout the oviduct and invaginations of the lining form tubular glands in all regions except the anterior infundibulum and the posterior vagina. The tubular glands are not alveolar, as reported in some other snakes, and simply represent a continuation of the oviducal lining with no additional specializations. The anterior infundibulum and vagina show the least amount of variation in relation to season or reproductive condition. In these regions, the epithelium is irregular, varying from squamous to columnar, and cells with elongate cilia alternate with secretory cells. The secretory product of the infundibulum consists largely of lipids, whereas a glycoprotein predominates in the vagina; however, both products are found in these regions and elsewhere in the oviduct. In the SST area and the anterior vagina, tubular glands are compound as well as simple. The epithelium of the SST is most active after mating, and glycoprotein vacuoles and lipid droplets are equally abundant. When present, sperm form tangled masses in the oviducal lumen and glands of the SST area. The glands of the uterus are always simple. During sperm migration, a carrier matrix composed of sloughed epithelial cells, a glycoprotein colloid, lipids, and membranous structures surround sperm in the posterior uterus. During gravidity, tubular glands, cilia, and secretory products diminish with increasing development of the fetus, and numerous capillaries abut the basal lamina of the attenuated epithelial lining of the uterus.

Animals↗

PubMed1978

Scanning electron microscope studies of the papilla basilaris of some turtles and snakes.

The papillae basilares of three species of turtles and four species of snakes were studied by SEM. The papillae of turtle are relatively large among reptiles and are characterized by a long, horizontal middle section resting on wide basilar membrane. Both terminal ends of the papilla extend onto the surrounding limbus in the form of a forked or "T" -shaped end or as a curved, "hook"- like processes. Details vary with the species. In the three species of turtles studied, there were between 1,100 and 1,400 hair cells on a papilla. The tectorial membrane covering the horizontal portion of the papilla is heavy in appearance and tightly attached to the kinocilial bulbs. The terminal ends of the papilla are covered by a thin gelatinous material. In addition, mat-like tectorial network covers the supporting cells and extends from the microvilli of the supporting cells to the overlying tectorial membrane. All hair cells are unidirectionally and abneurally oriented. The supporting cell surfaces form a large part of the papilla and, thus, hair cell density is low. The papillae of the two boid snake species studied are moderately long among snakes and contain a moderate number of hair cells (574 in Epicrates and 710-780 in Constrictor). Papillar form is elongate, avoid, or canoe-shaped. The tectorial membrane may be either highly fenestrated or moderately dense and covers all but a few of the terminal hair cells. A tectorial-like mat covers all but a few of the terminal hair cells. Most hair cells are unidirectionally and abneurally oriented. A few terminal cells in boids may show reverse orientation. Hair cell density is similar to that of turtles.

Animals↗

PubMed1988

Neurogenesis in the vomeronasal epithelium of adult garter snakes: 3. Use of H3-thymidine autoradiography to trace the genesis and migration of bipolar neurons.

Use of H3-thymidine autoradiography and unilateral vomeronasal (VN) axotomy has permitted us to demonstrate directly the existence of VN stem cells in the adult garter snake and to trace continuous bipolar neuron development and migration in the normal VN and deafferentated VN epithelium in the same animal. The vomeronasal epithelium and olfactory epithelium of adult garter snakes are both capable of incorporating H3-thymidine. In the sensory epithelium of the vomeronasal organ, H3-thymidine-labeled cells were initially restricted to the base of the undifferentiated cell layer in animals surviving 1 day following H3-thymidine injection. With increasing survival time, labeled cells progressively migrated vertically within the receptor cell column toward the apex of the bipolar neuron layer. In both the normal and denervated VN epithelium, labeled cells were observed through the 56 days of postoperative survival. In the normal epithelium, labeled cells were always located within the matrix of the intact receptor cell columns. However, labeled cells of the denervated epithelium were always located at the apical front of the newly formed cell mass following depletion of the original neuronal cell population. In addition, at postoperative days 28 and 56, labeled cells of the denervated VN epithelium achieved neuronal differentiation and maturation by migrating much farther away from the base of the receptor cell column than the labeled cells on the normal, unoperated contralateral side. This study directly demonstrates that basal cells initially incorporating H3-thymidine are indeed stem cells of the VN epithelium in adult garter snakes.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1984

Enhancement of adenosine 3',5'-monophosphate in human mononuclear and polymorphonuclear leukocytes by snake venoms.

Snake venoms contain compound(s) that enhanced cyclic AMP content in human mononuclear leukocytes maximally after 5 min of incubation at 37 degrees C. The effect was time- and dose-dependent. The half-maximal stimulation of cyclic AMP production by black cobra venom was found at 0.45 micrograms of venom/ml and the value of the Hill coefficient was 0.7. The black cobra venom enhanced the cyclic AMP content in the cells at 4, 22, and 37 degrees C. Similar increase in the cyclic AMP content by six snake venoms was found in human polymorphonuclear leukocytes. The most active venom was from puff adder (Bitis arietans). The data suggest that one of the effects of the snake venoms may be rapid enhancement of cyclic AMP level in the affected cells.

Alprostadil↗

PubMed1977

Tectal efferents in the branded water snake, Natrix sipedon.

Visual information reaches the dorsal thalamus by two distrinct routes in most reptiles. Retinal efferents terminate directly in the dorsal lateral geniculate nucleus (DLGN). Retinal information is also channeled indirectly through the tectum to nucleus rotundus. Retinal projections to DLGN and tectum are also well established in snakes, but the status of the tecto-rotundal link of the indirect visual pathway is uncertain. Thus, tectal efferents were studied with Fink-Heimer methods in banded water snakes (Natrix sipedon). The tectum gives rise to crossed and uncorssed projections to the brainstem reticular formation. Commissural connections are effected with the contralateral tectum via the tectal and posterior commissures. Tectum projects densely to the ipsilateral basal optic nucleus. Bilateral ascending projections reach the pretectal area, nucleus lentiformis mescencephali, lateral habenular nuclei, and posterodorsal nuclei. Ascending projections reach the ventral lateral geniculate and suprapeduncular nuclei. There is a diffuse projection to the central part of the caudal thalamus and a dense, bilateral projection to the DLGN. These results indicate that the relation of the tectum to the dorsal thalamus is different in snakes than in other reptiles. Nucleus rotundus is either absent or poorly differentiated and there is a strong convergence of the direct and indirect visual pathways at DLGN.

Animals↗

PubMed1993

First structure of a snake venom metalloproteinase: a prototype for matrix metalloproteinases/collagenases.

Adamalysin II, a 24 kDa zinc endopeptidase from the snake venom of Crotalus adamanteus, is a member of a large family of metalloproteinases isolated as small proteinases or proteolytic domains of mosaic haemorrhagic proteins from various snake venoms. Homologous domains have recently been detected in multimodular mammalian reproductive tract proteins. The 2.0 A crystal structure of adamalysin II reveals an ellipsoidal molecule with a shallow active-site cleft separating a relatively irregularly folded subdomain from the calcium-binding main molecular body composed of a five-stranded beta-sheet and four alpha-helices. The folding of the peptide fragment containing the zinc-binding motif HExxHxxGxxH bears only a distant resemblance to thermolysin, but is identical to that found in astacin, with the three histidines and a water molecule (linked to the glutamic acid) likewise constituting the zinc ligand; adamalysin II lacks a fifth (tyrosine) zinc ligand, however, leaving its zinc ion tetrahedrally co-ordinated. Furthermore, adamalysin II and astacin share an identical active-site basement formed by a common Metturn. Due to their virtually identical active-site environment and similar folding topology, the snake venom metalloproteinases (hitherto called adamalysins) and the astacins (and presumably also the matrix metalloproteinases/mammalian collagenases and the Serratia proteinase-like large bacterial proteinases) might be grouped into a common superfamily with distinct differences from the thermolysin family.

Amino Acid Sequence↗

PubMed1985

Hemodynamic adjustments to head-up posture in the partly arboreal snake, Elaphe obsoleta.

Radioactively-labeled microspheres were used to quantify adjustments of regional blood flows in 15 snakes (Elaphe obsoleta) subjected to 45 degrees head-up tilt. Heart rate and peripheral vascular resistance increased during tilt to compensate for the passive drop of pressure at the head. Two snakes failed to regulate blood pressure, but in 13 others arterial pressure increased at midbody (where passive changes in pressure are unexpected due to tilt alone) and arterial pressure at the head averaged 67% of the pretilt value. Tissue blood flow was reduced significantly in visceral organs, posterior skin and posterior skeletal muscle, but was maintained at pretilt levels in brain, heart, lung and anterior tissues. Ventricular systemic output averaged 24 ml/min X kg in horizontal posture and 9.4 ml/min X kg during tilt. Comparable values for pulmonary output were 4 and 6.5 ml/min X kg. Patterns of intraventricular shunting of blood acted to maintain pulmonary flow during tilt. A large right-to-left shunt (mean 76%) was present in horizontal snakes, but the shunted fraction declined during tilt (mean 54%). Left-to-right shunt increased during tilt from 7% to 14%.

Animals↗

PubMed2003

Histology of the extraembryonic membranes of an oviparous snake: towards a reconstruction of basal squamate patterns.

An understanding of the evolutionary morphology of extraembryonic membranes in reptiles requires information about oviparous as well as viviparous species. We are studying histology and ultrastructure of the extraembryonic membranes of snakes to clarify the evolutionary history of reptilian fetal membranes, including determination of basal (ancestral) ophidian and squamate patterns. Microscopic anatomy of the membranes of oviparous corn snakes (Elaphe guttata) was examined using light and electron microscopy. At mid-development the inner surface of the eggshell is lined by two extraembryonic membranes, the chorioallantois and the omphalallantoic membrane. The chorioallantois consists of a bilayered cuboidal epithelium that overlies the allantoic blood vessels. During development, allantoic capillaries become more abundant, and the chorionic epithelium thins, decreasing the diffusion distance for respiratory gas exchange. The abembryonic pole of the egg is delimited by a bilaminar omphalopleure and isolated yolk mass, the latter of which is lined on its inner face by the allantois. The isolated yolk mass regresses developmentally, and patches of yolk droplets become isolated and surrounded by allantoic blood vessels. By late development, the abembryonic hemisphere has been fully vascularized by allantoic vessels, forming a "secondary chorioallantois." With regard to its extraembryonic membranes, Elaphe gutatta is similar to viviparous snakes. However, this species exhibits features that have not previously been reported among squamates, perhaps reflecting its oviparous reproductive habits. Morphological evidence for the uptake of eggshell material by epithelia of the chorion and omphalopleure suggests that the potential for absorption by extraembryonic membranes predates the origin of viviparity.

Allantois↗

PubMed1976

Structure of anterior dorsal ventricular ridge in snakes.

Anterior dorsal ventricular ridge (ADVR) is a major subcortical, telencephalic nucleus in snakes. Its structure was studied in Nissl, Golgi, and electron microscopic preparations in several species of snakes. Neurons in ADVR form a homogeneous population. They have large nuclei, scattered cisternae of rough endoplasmic reticulum in their cytoplasm, and bear dendrites from all portions of their somata. The dendrites have a moderate covering of pedunculated spines. Clusters of two to five cells with touching somata can be seen in Nissl, Golgi, and electron microscopic preparations. The area of apposition may contain a series of specialized junctions which resemble gap junctions. Three populations of axons can be identified in rapid Golgi preparations of snake ADVR. Type 1 axons course from the lateral forebrain bundle and bear small varicosities about 1 mu long. Type 2 axons arise from ADVR neurons and bear large varicosities about 5 mu long. The origin of the very thin type 3 axons is not known; they bear small varicosities about 1 mu long. The majority of axon terminals in ADVR are small (1 mu to 2 mu long), contain round synaptic vesicles, and form asymmetric active zones. This type of axon terminates on dendritic spines and shafts and on somata. A small percentage of terminals are large, 5 mu in length, contain round synaptic vesicles, and form asymmetric active zones. This type of axon terminates only on dendritic spines. A small percentage of terminals are small, contain pleomorphic synaptic vesicles, and form symmetric active zones. This type of axon terminates on dendritic shafts and on somata.

Animals↗