[Evaluation of the efficacy of mannitol in the treatment of ciguatera in French Polynesia].

Up till now, in the French Polynesia and in New Caledonia, people showing ciguatera intoxication receive a standard treatment: calcium + vitamins B6 and C by intravenous way and in addition, some drugs arriving to cure some symptomatic manifestations. In 1988, an investigation carried out in Majuro, Marshall Islands concluded that intravenous mannitol is efficient in the treatment of serious intoxications with suspecting cerebral oedema. Since, such a treatment has been utilized with success in several endemic areas.

Bursts of ciguatera and endo-upwelling process on coral reef.

We propose a significant relationship between bursts of ciguatera following disturbance on a reef area and seepages of endo-upwelled interstitial waters, rich in nutrients. Such waters cannot continue to be used by a stressed or eliminated algal-coral ecosystem and are taken up by epibenthic planktons i.e.

[Risk factors of ciguatera in the French West Indies in Saint-Barthélémy, Saint-Martin and Anguilla].

An epidemiological study on ciguatera fish poisoning in the French West Indies (St-Barthelemy, St-Martin and Anguilla) was conducted during the years 1985-1986. The investigation on intoxications shows a non seasonal significant prevalence. Though it was difficult to list the cases, the morbidity seems to vary between 7 and 30 per thousand.

Ciguatoxin is a novel type of Na+ channel toxin.

Purified ciguatoxin at 0.1 to 10 ng/ml inhibits the net accumulation of neurotransmitters (gamma-aminobutyric acid and dopamine) by brain synaptosomes. This action is due to a stimulation of neurotransmitter release.

Effects of highly purified maitotoxin extracted from dinoflagellate Gambierdiscus toxicus on action potential of isolated rat heart.

Maitotoxin is a substance extracted from a dinoflagellate and certain tropical poisonous fish. It is considered as the most potent marine toxin (50 times more potent than tetrodotoxin). In isolated mammalian atria, maitotoxin produces at low doses a positive inotropic effect not modified by reserpine pretreatment and suppressed by Mn2+ ions.

The use of mosquitoes (Aedes aegypti) to detect ciguatoxin in surgeon fishes (Ctenochaetus striatus).

A new animal assay to detect ciguatoxin in fishes was developed. Mosquitoes were subjected to intrathoracic injection of serial dilutions of ciguatoxin crude extracts. Toxicity of the fishes was expressed as the mosquito LD50 (g of flesh per mosquito).

[Ciguatera: a rapid procedure for extraction of ciguatoxin].

A rapid procedure for extraction and partial purification of ciguatoxin has been achieved and compared to one of the routine methods. Fish from two species which provided extracts of differing purity by the routine method were used. From 8 g of raw flesh, 1.

Effects of ciguatoxin and maitotoxin on isolated rat atria and rabbit duodenum.

Ciguatoxin and maitotoxin, extracted from a species of moray-eel, Gymnothorax javanicus, and from a wild dinoflagellate, Gambierdiscus toxicus, were tested on rat atria and rabbit duodenum. Biphasic inotropic and chronotropic responses with excitatory and inhibitory components were observed. The effects of agents such as reserpine, propranolol, phentolamine, atropine and manganese ions were investigated.

Studies on the mode of action of ciguateric toxins.

The effects of ciguatoxin, scaritoxin and maitotoxin, the main toxins involved in ciguatera fish poisoning, has been studied in pentobarbital anaesthetized cats. Intravenous injections of increasing doses of these toxins (5 to 160 microgram/kg of partially purified samples) evoked respiratory and cardiovascular disturbances: hyperventilation at low doses and respiratory depression leading to respiratory arrest at high doses; bradycardia and troubles of the atrioventricular conduction at low doses, arrhythmias and ventricular tachycardia with transient hypertension at sublethal doses, and falling arterial pressure leading to complete heart failure at high doses. The mode of action of ciguatoxin has been studied by testing the preventive effects of pharmacological compounds such as hexamethonium, atropine, propranolol and phentolamine and by proceeding to bilateral adrenalectomy.

[Assay for detection of ciguatoxin using an immunoenzyme technic].

The ELISA method has been used to detect possible anticiguatoxin antibodies in the tissues of toxic fishes. Thin lamellae of toxic fish muscles have been brought into contact on the one hand with antibodies obtained after immunization of the rabbit and the mouse by a human serumalbumine ciguatoxin conjugate and on the other hand with human sera of ciguatera convalescent. These various antibodies have been recognized by peroxydase labelled anti-rabbit, -mouse and -human antibodies.

Clinical observations on 3,009 cases of ciguatera (fish poisoning) in the South Pacific.

Clinical observations on ciguatera were collected between 1964 and 1977 on 3,009 patients from several South Pacific island groups. Patients generally presented with neurologic symptoms such as parasthesia, vertigo, and ataxia, in addition to gastrointestinal symptoms such as diarrhea, abdominal pain, nausea, and vomiting. Patients with this illness usually became symptomatic less than 24 hours after ingestion of the fish and most patients (76.

[Ciguatera fish poisoning in New Caledonia. Clinical and epidemiological aspects (author's transl)].

The author studies the incidence of ciguatera fish poisoning on the public health in New Caledonia. He gives the results of a large scaled inquiry on the clinical and epidemiological aspects of the disease. The geographical distribution and the toxic species are discussed.

[A new pathophysiological explanation of ciguaterra (author's transl)].

After pointing out clinical, biochemical and biological similarities between paralytic shellfish poisoning and ciguaterra fish poisoning, the authors describe their recent discoveries in regard to ciguaterra origin. The causal agent searched without results since many years, might be a dinoflagellate, of the genus Diplopsalis.

[Significance of the various toxins present on dead coral substrata in the origin of ciguatera].

The authors look directly on the coral reefs the toxins carried by poisonous fish. Pointing out two major toxic substances, they discuss their respective role in ciguatera physiopathology and suggest a new hypothesis for the origin of the phenomenon.

[Toxic complex from parrotfish].

Clinical and epidemiological observations suggested that a complex toxic molecule is involved in the parrotfish flesh (Scarus gibbus) poisoning from Gambier Islands. The fat soluble extract obtained from the muscles upon ciguatoxin preparation showed two toxic substances after fractionation by DEAE cellulose column chromatography. The major toxin is different from ciguatoxin judging by its chromatographic behaviour.

[Neurologic complications of ciguatera].

The authors report a case of severe two phases fish poisoning, treated at hospital and ruled by a complex neurological picture with both central and peripheric manifestations. The detailed data, they have got about the disease, are an opportunity to discuss the various pathogenic procedures of human ciguatera.

[Fractionation of ciguatoxic lipid extracts in alkaline medium].

A modification of the extraction procedure for obtaining ciguatoxic substances from the tissues of various poisonous reef fish has been developed. Rapid alkali treatment of the residue obtained at an early stage is efficient in separating the ciguatoxic fraction from toxic impurities which interfere with pharmacological tests. It is thus possibles to carry out a more precise dosage of the material separated in this way.

[Comparative immunological study of protein extracts of poisonous and non-poisonous fishes (author's transl)].

Suggesting an immunologic participation in the pathogeny of the ciguateric syndroms, the authors have prepared a proteic antigen from the flesh of poisonous and edible fish of the same species. They have shown that there is a total common antigenicity between toxic and non toxic extracts. They suggest a new immunologic approach, in the matter of intoxication by ciguateric fish.