Sand bar opening in a coastal lagoon (Iquipari) in the northern region of Rio De Janeiro State: hydrological and hydrochemical changes.

The aim of this paper was to verify hydrological and hydrochemical changes in the Iquiparí Lagoon water column, during three months, as related to an artificial sand bar opening. A drastic reduction in water volume occurred 28 hours after the sand bar opening, exposing the bottom sediment. This was densely colonized by submerged aquatic plants, which were dominant in the ecosystem metabolism, specially near the sand bar. An increase in salinity values, and dissolved and total nutrient concentrations, was observed during the sand bar opening period. In contrast, chlorophyll a concentration decreased. These changes were associated with: 1) mix of remained brackish and marine waters; 2) nutrient release from sediments by physical processes; and 3) submerged plant death. After the sand bar closure, lagoon metabolism was completely regulated by a dense phytoplankton community. We observed that the sand bar opening resulted in an extensile replacement of the lagoon's water and a change in the community mainly responsible for the ecosystem metabolism.

Sand bar opening in a coastal lagoon (Iquipari) in the northern region of Rio de Janeiro State: hydrological and hydrochemical changes

The aim of this paper was to verify hydrological and hydrochemical changes in the Iquiparí Lagoon water column, during three months, as related to an artificial sand bar opening. A drastic reduction in water volume occurred 28 hours after the sand bar opening, exposing the bottom sediment. This was densely colonized by submerged aquatic plants, which were dominant in the ecosystem metabolism, specially near the sand bar. An increase in salinity values, and dissolved and total nutrient concentrations, was observed during the sand bar opening period. In contrast, chlorophyll a concentration decreased. These changes were associated with: 1) mix of remained brackish and marine waters; 2) nutrient release from sediments by physical processes; and 3) submerged plant death. After the sand bar closure, lagoon metabolism was completely regulated by a dense phytoplankton community. We observed that the sand bar opening resulted in an extensile replacement of the lagoon's water and a change in the community mainly responsible for the ecosystem metabolism

Coagulopathy following lethal and non-lethal envenoming of humans by the South American rattlesnake (Crotalus durissus) in Brazil.

The South American tropical rattlesnake (Crotalus durissus subspp) is responsible for approximately 10% of bites from venomous snakes in Brazil. We studied 24 victims of bites by this species over 3 years, in south-eastern Brazil, particularly investigating haemostatic alterations. Thirteen patients were defined as moderately envenomed and 11 as severe. There were two deaths, which were not attributed to venom-induced haemostatic disturbances. However, envenoming by C. durissus is frequently associated with haemostatic disorders, which are probably attributable mainly to the action of the thrombin-like enzyme, with possible additional effects secondary to the powerful myotoxic activity of the venom.

[Intracranial arachnoid cysts. Neuroendoscopic treatment]. / Cistos aracnóides intracranianos. Tratamento pela neuroendoscopia.

The author reports the techniques and results of seven patients with intracranial arachnoid cysts treated surgically, all of them through neuroendoscopic approach. Two carriers of supraselar cysts had undergone several shunt surgeries, and another carrier of a temporal cyst undergone external drainage to treat an associated subdural higroma. Only in this case the endoscopic approach has not resulted in control of the symptoms of the patient. The follow up period extended from one to nine years.

Platelet aggregation in patients bitten by the Brazilian snake Bothrops jararaca.

Patients bitten by the lancehead snake Bothrops jararaca usually develop systemic bleeding. Our aim was to evaluate platelet function in whole blood of 17 human patients bitten by this snake in São Paulo State, Brazil. Bleeding occurred in 71% of these patients, and thrombocytopenia in 53% of them. On admission, most of the patients presented with hypoaggregation to 50 microM ADP and 1.2 mg/ml ristocetin, and only 35% of them to 5 micrograms/ml collagen. Abnormal plasma levels of fibrinogen and fibrin(ogen) degradation products (FDP/fdp) were also observed. Twenty-four hours of finishing serumtherapy, bleeding had already ceased, fibrinogen and FDP/fdp levels returned to hemostatic levels, and values for platelet aggregation returned to the reference range of controls, except for ADP that still remained decreased. These findings evidence that disturbances of platelet function are also an important factor for the development of bleeding in Bothrops envenomation, as well as other known hemostatic disturbances that occur concomitantly.

Snakebite by the bushmaster (Lachesis muta) in Brazil: case report and review of the literature.

The bushmaster (Lachesis muta) of Central and South America, the world's longest pit viper, is capable of injecting a large dose of potent venom when it bites. A 28-year-old man, bitten by a 1.82 m long L. m. muta in Brazil, developed pain and oedema at the bite site, nausea, vomiting, diarrhoea and sweating. There was peripheral neutrophil leucocytosis and evidence of fibrinogen consumption with secondary activation of the fibrinolytic system. Two hours after the bite, eight ampoules of Instituto Butantan Lachesis antivenom was administered, and haemostasis was normal 24 hr later. A review of reports of 20 cases of bites in humans reliably attributed to this snake in Costa Rica, French Guiana, Brazil, Colombia and Venezuela confirms a syndrome of nausea, vomiting, abdominal colic, diarrhoea, sweating, hypotension, bradycardia and shock, possibly autopharmacological or autonomic in origin, not seen in victims of other American crotaline snakes. These, and other symptoms of bushmaster envenoming, are explained by haemorrhagic, coagulant and neurotoxic venom activities. The therapeutic efficacy of non-specific Bothrops/Crotalus polyvalent antivenoms in these cases has been unimpressive. For the treatment of bites by a snake which potentially injects a large dose (> 300 mg dry weight) of venom with a range of life-threatening activities, there is an urgent need to develop more potent specific antivenoms and to treat the dramatic and life-threatening cardiovascular symptoms.

Adsorption of plasma proteins to DMAA hydrogels obtained by ionizing radiation and its relationship with blood compatibility.

The interaction of plasma proteins such as albumin, gamma-globulin, and fibrinogen with the surface of graft copolymers DMAA-G-PTFE, DMAA-G-PETFE, and DMAA-G-PE obtained by radiation graft polymerization was studied. The adsorption of serum proteins was affected by the hydrophilicity of the graft copolymers. Increased albumin adsorption and decreased fibrinogen and gamma-globulin adsorption with increasing grafting levels was shown. A certain range of degrees of grafting showed an improved blood compatibility of the polymeric surfaces due to the existence of a hydrophilic/hydrophobic balance on the polymers. The results suggest that the DMAA-G-PTFE, DMAA-G-PETFE, and DMAA-G-PE graft copolymers can be used as biomaterials for long-term use in cardiovascular systems.

A randomized 'blinded' comparison of two doses of antivenom in the treatment of Bothrops envenoming in São Paulo, Brazil.

An earlier study in São Paulo state suggested that the dose for patients with mild or moderate envenoming by Bothrops snakes (mainly Bothrops jararaca) could be effectively decreased to 4 ampoules (40 mL) of Brazilian Brothrops polyspecific antivenom. The present 'blinded' study examined the lowest dose studied in the first trial (equivalent to 4 x 10 mL ampoules) and half that dose of antivenom (equivalent to 2 x 10 mL ampoules) in 2 similar groups of 170 patients who were comparable in all respects before treatment. The majority of patients showed rapid clinical improvement after treatment with either dose regimen and rapid restoration of blood coagulability and cessation of bleeding. There was no apparent difference between the 2 groups of patients in any respect. The study confirmed that, in such patients, the dose of antivenom can be decreased from 4 ampoules to 2 ampoules without reduction of therapeutic efficacy, and it is highly likely that this reduction will result in a decrease of early anaphylactic reactions caused by the antivenom.

Reliability of the simple 20 minute whole blood clotting test (WBCT20) as an indicator of low plasma fibrinogen concentration in patients envenomed by Bothrops snakes. Butantan Institute Antivenom Study Group.

Reliability of the simple 20 minute whole blood clotting test (WBCT20) as an indicator of low plasma fibrinogen concentration in patients envenomed by Bothrops snakes. Toxicon 32, 1045-1050, 1994.--A simple whole blood clotting test (WBCT20) was assessed for its efficacy in determination of severe defibrinogenation in patients envenomed by Bothrops snakes in Brazil. There was a close relationship between the results of the WBCT20 and plasma fibrinogen levels in 69 moderately envenomed patients. The advantage of the WBCT20 over estimation of plasma fibrinogen concentrations in patients is that it is a simpler, faster and more reliable test. It is also of use in assessing the effectiveness of antivenom therapy in relation to the restoration of blood coagulability.

[Cerebrovascular disorders in Uberlandia: I. Mortality]. / Doenças cerebrovasculares em Uberlândia: I. Mortalidade.

We have analyzed 1361 death certificates, during the year of 1982 in Uberlandia (Brazil), all deaths of residents and not deathbirths. In 47% the deaths were assisted by a physician and the cause of death proved. The first basic cause of death found was cardiovascular diseases (23.3%). The second, infectious diseases particularly Chagas' disease (14.9%) and the third traumatic lesions and poisonings (14.4%). Cerebrovascular diseases were the seventh basic cause of death (6.5%) but the third most related disease at the death certificates (12.7%). It is important to stress that the mortality index change considerably if we consider the disease as a basic cause of death or in more than one position in the death certificate. For instance in Uberlandia the index for CVD was 30 and 63/100.000 inab/year, respectively. The carriers of arterial hypertension presented CVD related at death certificate 10 times more than in the not carriers of hypertension.

[Cerebrovascular disorders in Uberlandia: II. Epidemiology and clinic medicine]. / Doenças cerebrovasculares em Uberlândia: II. Epidemiologia e clínica.

We have studied prospectively 157 patients with stroke admitted at University Hospital and Hospital Santa Genoveva in Uberlandia, Brazil at the point of view of clinics and epidemiology. Incidence was 0.8/1000 peoples/year and early letality of stroke victims was 40%, only 30% had returned to work. Complete infarct account for 36.3% of the cases and was predominant in white man among stroke population. Hypertension (in 55% of the cases), Chagas' disease (26.1%), transient isquemic attack (22.7%) and hypercolesterolemia were the main risk factors for stroke in this region.