Six New Cases of a Caterpillar-Induced Bleeding Syndrome

We describe six new cases of a hemorrhagic diathesis induced by contact with Lonomia achelous caterpillars. Onset of clinical bleeding varied between a few hours and 10 days post-exposure. Laboratory coagulation tests showed prolonged PT, PTT and ThT; normal platelets and a marked decrease of fibrinogen, factor V, plasminogen and factor XIII (including its subunits A and S). Factors VII, II and alfa 2 anti-plasmin were variably affected. In addition, activation of the fibrinolytic system and the generation of a procoagulant effect could also be demonstrated. Two cases developed severe hemorrhagic diathesis and one of them died of a cerebral hemorrhage. Different aspects of this rare syndrome are discussed in relation to its complex physiopathology and the variability observed in all clinical and laboratory manifestations. Therapeutic recommendations and some possible hazards following replacement transfusions are also considered.

Studies on the Degradation of Fibrinogen by Proteolytic Enzymes from the Larvae of Lanomia achelous (Cramer)

Fibrinogen degradation products formed by the action of purified haemolymph and saliva of a Satumidae caterpillar of the Lonomia genus were studies by immunoelectrophoresis and polyacrylamide/SDS gel electrophoresis.

The pattern of degradation differ form the one described for plasmin, trypsin, brinase and ochrase. The most striking difference being the rapid loss of the a chain in spite of the presence of the protease inhibitor aprotinin, and/or denaturalizing agents such as 8 M Urea and 2% SDS.

A mouse model to study the alterations in haemostatic and inflammatory parameters induced by Lonomia achelous caterpillar haemolymph

A mouse model was established to reproduce the haemorrhagic syndrome which occurs in humans after accidental contact with the hairs of the caterpillar Lonomia achelous (LA) and measures the haemostatic and inflammatory alterations that occur as a result of this contact. Mice were injected intradermally with different doses (0.4, 0.8 and 1.6 mg/animal) of L. achelous haemolymph (LAH). Haematological (haemoglobin, haematocrit, platelet count, differential leukocyte count), haemostatic (fibrinogen, plasminogen, factor XIII [FXIII], fibrinolytic activity) and inflammatory parameters (tumour necrosis factor alpha [TNF-α], nitric oxide [NO]) were measured at different times up to 48 h. C57BL/6 mice responded to LAH injection, in terms of these parameters, in a manner similar to that seen in humans, whereas the BALB/c mice were unresponsive. In C57BL/6 mice injected with LAH, time course measurements showed: a) a reduction in the haemoglobin, haematocrit, fibrinogen, FXIII and plasminogen levels, b) no effect on the platelet count and c) immediate leukocytosis and an increase in the fibrinolytic activity in plasma. An inflammatory response (TNF-α) was observed within 1 h post-injection, followed by a more persistent increase in serum NO. These findings suggest that C57BL/6 mice represent a useful model of the haemorrhagic syndrome observed in humans who have suffered contact with the caterpillar, permitting a deeper understanding of the role of the inflammatory response in the haematological and haemostatic manifestations of this syndrome.

Invertebrate compounds acting on the hemostatic mechanism

Physiological secretions from some invertebrates have toxic effects on mammalian blood coagulation and fibrinolytic systems. Some of these effects occur because the substances contained in the secretions resemble the components of the hemostatic system. Some of the substances have been characterized, and have been found to have similar molecular weights or sequences, which may indicate a common ancestry. The components can be divided into five groups: antithrombic agents (group I); inhibitors and activators of the prothrombinase complex (group II); substances that affect platelet function (group III); substances that affect the fibrinolytic mechanism (group IV); and a group of miscellaneous agents whose activities are difficult to group together (group V). In group I special mention of the antithrombin agents in Hirudo medicinalis should be made. In group II, the agents affecting the prothrombinase complex are antistasin from Haementeria officinalis, ghilanten from Haementeria Ghiliani and the tick anticoagulant protein from Ornithodoros moubata, a factor V activator/inhibitor from Lonomia achelous and factor II and factor X activators from L. achelous and Lonomia obliqua. Examples of factors which affect platelet function (group III) are glossina from the black fly Glossina morsitans, calin from H. medicinalis, decorsin (a desintegrin) from Macrobdella decorsa, and FAGA from Stichopus japonicus selenka. The first three of these are inhibitors of platelet aggregation, and the last is an inducer. The plasminogen activators (group IV) from the L. achelous caterpillar and Eutriatoma maculata trigger the fibrinolytic system, whereas hementin from H. officinalis and hementerin from Haementeria depressa are directly fibrinolytic. The last group of substances (group V) include those with factor-XIIa-like activity from D. farinae, kallikrein-like activity and a factor XIII degrading enzyme from L. achelous, destabilase from H. medicinalis and prolixin S (nitroforin 2, or anti-factor-IXa) from Rhodnius prolixus. Some of these components have been well characterized, cloned and prepared in recombinant form, and seem to be very promising from the therapeutic point of view.

[Evaluation of methods for the diagnosis of Helicobacter pylori infection]

Helicobacter pylori is a gram negative curved bacillus recognized as etiologic agent of chronic gastritis and an important factor in the development of duodenal ulcer and gastric cancer. The purpose of this work is to evaluate three microbiologic methods for diagnosing H. pylori infection. We studied 375 samples from 218 patients, who consulted at the Department of Gastroenterology of the Hospital Vargas and were candidates for endoscopy. Samples of gastric mucous tissue were taken at level of the antrum and each sample was stained with Gram, tested for urease and cultured.

RESULTS

whit H. pylori positive 123 patients with duodenal ulcer at the endoscopy (91.1%), 17 had gastric ulcer (76.5%), 40 gastritis and/or duodenitis (60.0%), 1 duodenal ulcer and gastric (100.0%) and 37 normal endoscopies (56.8%). Evaluating the three methods used we found that of the 286 H. pylori positive samples, the Gram stain detected 282 (sensibility 98.6% and specificity 96.6%); the urease test 276 (sensibility 96.5% and specificity 98.6%) and culture was positive in 255 samples (sensibility 89.2% and specificity 100.0%). These results show that both the Gram stain and Urease test are useful for diagnosing H. pylori infection due to their high sensitivity and specificity, rapidness, low cost for the Gram stain, and easy interpretation for Urease test. Culture, even though less sensitivity++, represents the most unquestionable diagnosis and permits carrying out susceptibility to antimicrobials tests.

Six new cases of a caterpillar-induced bleeding syndrome

We describe six new cases of a hemorrhagic diathesis induced by contact with Lonomia achelous caterpillars. Onset of clinical bleeding varied between a few hours and 10 days post-exposure. Laboratory coagulation tests showed prolonged PT, PTT and ThT; normal platelets and a marked decrease of fibrinogen, factor V, plasminogen and factor XIII (including its subunits A and S). Factors VII, II and alfa 2 anti-plasmin were variably affected. In addition, activation of the fibrinolytic system and the generation of a procoagulant effect could also be demonstrated. Two cases developed severe hemorrhagic diathesis and one of them died of a cerebral hemorrhage. Different aspects of this rare syndrome are discussed in relation to its complex physiopathology and the variability observed in all clinical and laboratory manifestations. Therapeutic recommendations and some possible hazards following replacement transfusions are also considered.

An A alpha Ser-434 to N-glycosylated Asn substitution in a dysfibrinogen, fibrinogen Caracas II, characterized by impaired fibrin gel formation

We have identified a unique N-glycosylated Asn substitution for a Ser at position 434 of the A alpha chain of an abnormal fibrinogen designated fibrinogen Caracas II. This dysfibrinogen was characterized by impaired fibrin monomer aggregation. Since there were 4 Thr residues immediately following the mutation, a new Asn-X-Thr/Ser-type consensus sequence, Asn-Thr-Thr arose for N-glycosylation of the Asn. The extra oligosaccharide was found to consist mainly of a disialylated biantennary structure comprising 81.9%, while a neutral and a monosialylated biantennary oligosaccharide represented only 3.6% and 14.5%, respectively. The mutation resides in the carboxyl-terminal region of the A alpha chain, which could fold back to form an extra small globular region located near the central region of the molecule (Erickson, H.P., and Fowler, W.E. (1983) Ann. N. Y. Acad. Sci. 408, 146-163; Weisel, H.P., Stauffacher, C.V., Bullitt, E., and Cohen, C. (1985) Science 230, 3124-3133). Therefore, the participation of this region, referred to as an additional central domain or an alpha domain, in fibrin gel formation is strongly implicated.

Studies on the degradation of fibrinogen by proteolytic enzymes from the larvae of Lanomia achelous (Cramer)

Fibrinogen degradation products formed by the action of purified haemolymph and saliva of a Saturnidae caterpillar of the Lonomia genus were studies by immunoelectrophoresis and polyacrylamide/SDS gel electrophoresis. The pattern of degradation differ form the one described for plasmin, trypsin, brinase, and ochrase. The most striking difference being the rapid loss of the alpha chain in spite of the presence of the protease inhibitor aprotinin, and/or denaturalizing agents such as 8 M Urea and 2% SDS.