A.H. Mohamed

Proteins, lipids, lipoproteins and some enzyme characterizations of the venom extract from the centipede Scolopendra morsitans

Some components of Scolopendra morsitans venom extract were characterized using disc gel electrophoresis and thin layer chromatography. Its protein component was separated into 13 anodal bands and a slowly moving cathodal band. The extract showed three slowly moving lipoprotein bands and the lipid components included phospholipids, cholesterol, free fatty acids, triglycerides, cholesterol esters and squalene. The enzymes esterase, acid and alkaline phosphatases and amino acid naphthylamidase were present in multiple forms. Acid phosphatase isoenzymes were of low activity.

Studies of phospholipase A and B activities of Egyptian snake venoms and a scorpion toxin

Abstract Phospholipase A and B activity of several Egyptian snake venoms and scorpion toxin was determined by employing the rates of hydrolysis of lecithin and lysolecithin indicating phospholipase A activity and phospholipase B activity, respectively. Phospholipase A showed maximal activity at pH range 7·0–9·0. Marked activation of the enzyme occurred upon the addition of ether, sodium deoxycholate, Ca 2+ and Mg 2+ , while inhibition occurred upon the addition of EDTA, or a combination of sodium deoxycholate and calcium. The enzyme phospholipase B showed maximal activity at pH range 8·0–10·0 and was inhibited by EDTA and ether.

Effects of an extract from the centipede Scolopendra moristans on intestine, uterus and heart contractions and on blood glucose and liver and muscle glycogen levels

Abstract scolopendra extract caused initial inhibition of rabbit intestine followed by a marked excitation and finally a prolonged phase of inhibition. This effect was abolished by atropine and cyproheptadine (blockers of acetylcholine and serotonin respectively) but not by adrenergic blockers (hydergine and propranolol). The extract induced relaxation of the non-gravid uterus and slight inhibition of the normal contraction of the gravid uterus. These effects were blocked by the adrenergic blocking agents. The extract causes an inhibitory effect on the isolated heart of the toad which appeared to be due to the release of acetylcholine and was blocked by atropine. Scolopendra extract causes hyperglycaemia simultaneously with liver and muscle glycogenolysis. It is suggested that both effects are mediated through a serotonin like action of the extract.

Some enzymatic activities of Egyptian snake venoms and a scorpion venom.

Abstract The enzymatic activities of proteinase, cholinesterase, transaminases (glutamic oxalacetic transaminase and glutamic pyruvic transaminase) and amylase were estimated in several Egyptian snake venoms and in a scorpion venom. All venoms showed proteinase activity in varying degrees, while cholinesterase was found only in Naja haje and Walterinessia aegyptia venoms; the glutamic pyruvic transaminase activity was recorded in all venoms except Naja nigricollis and the scorpion venom, although no glutamic oxalacetic transaminase or amylase action was found in any of the venoms. All the enzymes were heat labile.

Glycaemic responses to scorpion venom

Hyperglycaemia and liver and muscle glycogenolysis were produced in the rat by scorpion venom. These epinephrine-like effects may be mediated by the serotonin present in the venom. Liver slices, excised from venom treated rats, and incubated in Krebs-Ringer solution with bicarbonate and glucose, exhibited an increase of free fatty acid release. Similarly treated liver slices from normal rats displayed a lipolytic effect in the presence of venom. Also, augmented glycogen deposition and increased hepatic glucose output were observed. It is proposed that this gluconeogenesis is due to the lipolytic action of the venom. Venom treatment of rats had no effect on glucose uptake of hemidiaphragms incubated in vitro in Krebs-Ringer solution with glucose. Hemidiaphragms from normal rats showed inhibition of glucose uptake at a high in vitro venom concentration. The effect of the venom on glucose uptake and free fatty acid release by rat epididymal fat pads incubated in Krebs-Ringer solution with glucose, was also studied. An augmented glucose uptake was obtained. No significant effect on free fatty acid release was observed. This insulin-like effect was ascribed to its phospholipase-A component. The lack of a lipolytic action was attributed to inactivation of the venom serotonin by monoamine oxidase and phosphodiesterase of adipose tissue. A similarity between the effects of scorpion venom on rat muscle and adipose tissue and those of the Vallance-Owen synalbumin insulin antagonist was found.

Effects of several snake venoms on serum and tissue transaminases, alkaline phosphatase and lactate dehydrogenase

Abstract The effect of lethal doses of five venoms ( Bitis arietans, Bitis gabonica, Dendroaspis polylepis, Naja nigricollis and Naja haje ) on the activities of transaminases, alkaline phosphatase and lactate dehydrogenase were studied. Samples from the serum, liver, heart and kidney were collected 4 hr following lethal venom injections in albino rats. The activity of these enzymes were markedly increased in serum and variably decreased in the liver, heart and kidney after envenomation.

Histopathological effects of Naja haje snake venom and a venom gland extract of the scorpion Buthus quinquestriatus on the liver, suprarenal gland and pancreas of mice

Abstract Lethal doses of Naja haje snake venom produced central and midzonal hydropic degeneration in hepatic lobules. Buthus quinquestriatus scorpion venom gland extract caused peripheral zonal hydropic degeneration, sinusoidal dilatation and disruption. Fatty degenerative changes started earlier after use of the scorpion preparation. Both preparations depleted glycogen, inhibited succinic dehydrogenase and increased alkaline phosphatase activity in degenerated hepatocytes. Signs of regeneration followed sublethal doses of Naja haje venom. Lethal doses of both venom preparations caused rupture of the capsule of the suprarenal gland and detachment of its cortex. Blood extravasated in the medulla. Zona fasciculata cells were hypertrophied and vacuolated and cortical lipids increased. Depletion of ascorbic acid and medullary catecholamines occurred. After a single sublethal dose the zona reticularis region increased in thickness due to proliferation of its cells. These cells invaded the medullary clumps. Repeated sublethal doses increased the thickness of both the zona fasciculata and reticularis. In the pancreas, lethal doses of both venom preparations produced vacuolization of alpha and beta cells. Partial and complete degranulation were observed in hydropically degenerated beta cells. Alpha cells showed decreased alkaline phosphatase activity.

Effect of Cerastes vipera snake venom on blood and bone marrow cells.

Abstract A. H. Mohamed , A. M. Saleh , S. Ahmed and M. El-Maghraby . Effect of Cerastes vipera snake venom on blood and bone marrow cells. Toxicon 15, 35–40, 1977.— In vivo experiments Lethal doses of Cerastes vipera venom injected intraperitoneally in rabbits produced a significant initial rise of the erythrocyte count 15 min after venom injection, followed by a progressive drop. Total leucocyte and platelet counts gradually dropped. The bone marrow picture showed erythroid hyperplasia 3–4 hr after venom injection. Sublethal doses produced a small insignificant initial rise of red cell count followed by a progressive drop during the first hr. In the second hr the counts rose and gradually reached the pre-injection levels after 24 hr. An initial leucopenia and thrombocytopenia was followed by fluctuations in both counts with significant leucocytosis and increased percentage of neutrophil after 24 hr. The platelet counts reached the pre-injection values in 24 hr. The bone marrow picture revealed erythroid hyperplasia 5–6 hr after venom injection. Reticulocyte counts were above normal levels. In vitro studies Incubation of 1 ml blood with 0·5 mg venom for 1 hr resulted in marked haemolysis as evidenced by reddish coloration of plasma, decreased rouleaux formation, microspherocytosis, disruption of leucocytes and drop of all cell counts.

Histopathological and histochemical changes in skeletal muscles after Bitis gabonica envenomation.

Abstract The histochemical activities of succinic dehydrogenase and cholinesterase in skeletal muscles of the mouse were studied after i.m. administration of B. gabonica venom. There was generalized depletion of succinic dehydrogenase activity 48 hr after injection of an ld 50 (18 μg per 25 g body wt). The subsarcolemmal density which typifies type C fibres was reduced. In the chronically treated animals which received 0.5 ld 50 at weekly intervals for 5 weeks, the normal granular pattern of the reaction became diffuse thus diminishing the differences between the enzyme activities in different fibres. Generalized reduction in fibre size similar to denervation atrophy was observed. The cholinesterase activity was not affected in either in vitro or in vivo experiments. In acutely treated animals receiving one ld 50 haemorrhages and extravasation of blood cells was observed. Animals receiving 0.5 ld 50 showed haematoma at the site of injection after 24 days. Histopathological changes included extensive vacuolization along the course of dilated intramuscular blood vessels. Interruption of their endothelial lining was detected in certain areas. Muscle tissue was either absent or showed vacuolization with non-specific cellular infiltration. Fasciculation, intra-fibral vacuolization and loss of transverse striations was observed. Nerve trunks were partially degenerated and contained variably sized empty vesicles. Degenerated motor end plates were present. Away from the site of injection normal muscle fibres, intramuscular nerve trunks and motor end plates were observed.

Immunological studies on Egyptian cobra antivenin

Abstract A monovalent specific antivenin was prepared in horses against the Egyptian cobra (Naje haje) venom; using bentonite as an adjuvant. One ml of the serum tested at the end of the six-month program neutralized 64 ld 50 and protected against 53 ld 50 in mice. Cross immunological studies were carried out with five elapid, six viperid and one crotalid venoms. The serum proved effective in neutralization of and protection against these venoms. Precipitation reaction lines were obtained using the Ouchterlony technique, with most of the venoms. Identity patterns were established between venoms of N. haje, N. nigricollis, N. flava, N. naja, Walterinnesia aegyptia of the Elapidae as well as those of Echis carinatus and Ethiopian N. haje. Partial identity with the two vipers Cerastes cerastes and Cerastes vipera and nonidentity with Echis coloratus venom. Weak or no reactions were given with the Ethiopian Bitis lachesis, Bitis gabonica and the Japanese Trimeresurus flavoviridis.