Influence of environmental factors on the response of a natural population of Daphnia magna (Crustacea: Cladocera) to spinosad and Bacillus thuringiensis israelensis in Mediterranean coastal wetlands.

The present study was undertaken to assess the impact of a candidate mosquito larvicide, spinosad (8, 17 and 33 microg L(-1)) on a field population of Daphnia magna under natural variations of water temperature and salinity, using Bti (0.16 and 0.50 microL L(-1)) as the reference larvicide. Microcosms (125 L) were placed in a shallow temporary marsh where D. magna was naturally present. The peak of salinity observed during the 21-day observation period may have been partly responsible for the decrease of daphnid population density in all the microcosms. It is also probably responsible for the absence of recovery in the microcosms treated with spinosad which caused a sharp decrease of D. magna abundance within the first two days following treatment whereas Bti had no effect. These results suggest that it may be difficult for a field population of daphnids to cope simultaneously with natural (water salinity and temperature) and anthropogenic (larvicides) stressors.

Effects of spinosad and Bacillus thuringiensis israelensis on a natural population of Daphnia pulex in field microcosms.

Spinosad, a candidate biological larvicide for mosquito control, was evaluated for its effects on a field population of Daphnia pulex, using Bacillus thuringiensis serovar israelensis (Bti) as a reference larvicide. Microcosms (125L enclosures) were placed in a shallow temporary oligohaline marsh where D. pulex was present. Three concentrations of spinosad (8, 17 and 33 microg L(-1)) and two concentrations of Bti (0.16 and 0.50 microL L(-1)) were applied (5 replicates per concentration, including the controls). Effects of larvicides on D. pulex were evaluated after 2, 4, 7, 14 and 21d of exposure, through measurements of abundance and individual size. Dissipation of spinosad from the water phase was rapid. Four days after treatment, residue concentration represented 11.8%, 3.9% and 12.7% of the initial exposure level for the nominal concentrations of 8, 17 and 33 microg L(-1), respectively. Spinosyns A and D dissipated at similar rates. Analysis of abundance and size structure of the D. pulex population showed an impact of spinosad. Both survival and size structure were affected. However, at the lowest concentration (8 microg L(-1)), population recovered after the first week. In microcosms treated with Bti, the abundance of D. pulex was not affected but the size structure of the population changed after 21d. As compared to laboratory tests, the use of in situ microcosms improved the environmental risk assessment of larvicides, taking into account the influence of environmental factors (e.g., temperature, light, salinity) and intrinsic capacity of recovery of D. pulex under field conditions.

[Asystolias in the acute phase of brain stroke. Report of a case]. / Asistolias en la fase aguda del infarto cerebral. A propósito de un caso.

Brain areas involved in heart autonomic control are not well characterized. Insulae have been proposed as control centers. A lesion in these areas may induce a cardiac autonomic dysfunction (arrhythmias, atrioventricular conduction abnormalities). Asystolia has not been previously reported. A 65-year-old man suffered an acute ischemia of the right middle cerebral artery (MCA) territory. NIHSS score was 19 points. Brain CT scan was normal. Transcranial Doppler (TCD) showed occlusion of the right MCA. Fibrinolysis was initiated 135 minutes after stroke onset with TCD monitoring. Twenty minutes later he suffered cardiac arrest with asystolia trace in the ECG monitor. Fibrinolysis was stopped during resuscitation. Four minutes later, he recovered with the same NIHSS score. Aggressive resuscitation maneuvers were not necessary. A repeated brain CT scan showed infarct signs in the whole MCA territory and a new TCD did not show any change. Serial blood analyses including cardiac nzymes were normal. The patient experienced four brief cardiac arrests in the next nine hours, so a temporary cardiac pacemaker was placed for four days. He was treated with aspirin and was discharged 14 days after admission. He has not experienced recurrences during a 6-month follow-up. We could not diagnose the etiology of the cardiac arrests. All the episodes occurred in the acute stroke stage and arrhythmia, atrioventricular block, myocardial ischemia or structural lesions were not found in the cardiac study. We propose that ischemia in the right insula induced sudden and transitory interruptions of the sympathetic cardiac tone.

[Intra-arterial fibrinolysis in vertebrobasilar system]. / Fibrinólisis intrarterial en el territorio vertebrobasilar.

INTRODUCTION: The acute vertebrobasilar occlussion is usually a life-treatening disease leading to death or major disability. The treatment with heparin and the selective fibrinolysis no show good results, for this reason the local intra-arterial fibrinolysis appear as the choice treatment in patients with stroke and a agiography with basilar artery occlussion or intracranial vertebral artery occlusion. This tecnique has been proved to be effective treatment for selected patients with acute thromboembolic occlusion of the middle cerebral artery, ophthalmic artery and vertebrobasilar system, reducing the mortality in the vertebrobasilar system from 90% to 40%. CLINICAL CASE: We present a 63 years-old man with a vertebrobasilar thrombosis of a probable cardioembolic origen. He was treated with r-TPA local intra-arterial fibrinolysis, to get a recanalization of vertebrobasilar system. In the control TC we see a haemorragic sufusion in the brain stem. The follow-up see a patient with tetraparesis and palsy of the low cranial nerves and normal superior cerebral functions. CONCLUSIONS: The local intra-arterial fibrinolysis is the choise treatment in the vertebrobasilar thrombosis because the high morbimortality of this patology and the inefficacy of the others therapeutics. The result depend of many factors as the thrombo location, the neurologic state, the evolution time, the start of treatment, the colateral circulation, the nervous tissue reserve, etc, that have dificult predict the result, but it is best of the natural history of the disease. Is necesary, change the concept of emergency and the attitude front the isquemic cerebral disease at the sanitary leaders, the doctors, and the general population, for dispose of more means to cofront this pathology, which permit diminish the morbimortality and reduce the grade of incapacity.