No abstract

The features of Ca 2+ fluxes, the importance of the Ca 2+ pump-mediated H + /Ca 2+ exchanges at plasmalemma level, and the possible involvement of Ca 2+ -ATPase activity in ABA-induced changes of H + fluxes were studied in Egeria densa leaves. The results presented show that, while in basal conditions no net Ca 2+ flux was evident, a conspicuous Ca 2+ influx (about 1.1 µmol g -1 FW h -1 ) occurred. The concomitant efflux of Ca 2+ was markedly reduced by treatment with 5 µM eosin Y (EY), a specific inhibitor of the Ca 2+ -ATPase, that completely blocked the transport of Ca 2+ after the first 20 -30 min. The decrease in Ca 2+ efflux induced by EY was associated with a significant increase in net H + extrusion (-∆H + ) and a small but significant cytoplasmic alkalinization. The shift of external [Ca 2+ ] from 0.3 to 0.2 mM (reducing Ca 2+ uptake by about 30 %) and the hindrance of Ca 2+ influx by La 3+ were accompanied by progressively higher -∆H + increases, in agreement with a gradual decrease in the activity of a mechanism counteracting the Ca 2+ influx by an nH + /Ca 2+ exchange. The ABA-induced decreases in -∆H + and pH cyt were accompanied by a significant increase in Ca 2+ efflux, all these effects being almost completely suppressed by EY, in line with the view that the ABA effects on H + fluxes are due to activation of the plasmalemma Ca 2+ -ATPase. These results substantially stress the high sensitivity and efficacy of the plasmalemma Ca 2+ pump in removing from the cytoplasm the Ca 2+ taken up, and the importance of the contribution of Ca 2+ pump-mediated H + /Ca 2+ fluxes in bringing about global changes of H + fluxes at plasmalemma level.

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Orthostatic hypotension is a frequent non-motor symptom of Parkinson's disease, with negative prognostic role on cognitive functions. Here we measured the acute effects of orthostatic hypotension on executive functions in Parkinson's disease patients devoid of hypertension, carotid artery stenosis, and significant chronic cerebrovascular pathology. Measurements were carried out during regular visits in outpatient setting. Twenty-eight Parkinson's disease patients were recruited and studied along scheduled outpatient visits. They were divided into two groups (n = 14 each) based on the presence or lack of orthostatic hypotension. This was diagnosed according to international guidelines. All patients were submitted to the Stroop's test and to the phonological and semantic verbal fluency test after 10-min resting in supine position and immediately upon standing in upright position. Testing lasted less than 5 min in either position. In upright position, subjects with orthostatic hypotension displayed significantly worse performances at the Stroop's test word reading time (22.1 ± 4.1 vs. 14.9 ± 4.0 s), interference time (56.1 ± 12.3 vs. 41.4 ± 11.8 s), and number of errors at the interference section (5.8 ± 3.2 vs. 1.3 ± 2.1) as compared to those without orthostatic hypotension. These results demonstrate that worsening of attentive function upon standing can be measured in Parkinson's disease patients with orthostatic hypotension during routine outpatient visits. These findings suggest that clinically asymptomatic orthostatic hypotension in Parkinson's disease patients may acutely worsen neuropsychological performances with possible negative impact on daily functioning.

No abstract

Wearing-off refers to the predictable worsening of motor and sometimes non-motor symptoms of Parkinson's disease occurring at the end of levodopa dose that improves with the next drug dose. Here, we investigated the efficacy of rasagiline on executive functions at the end of levodopa dose in patients displaying symptoms of wearing-off. Rasagiline was well-tolerated and produced a significant improvement at the Frontal Assessment Battery, together with improvement of motor symptoms at the end of levodopa dose. These results suggest that treatment of motor symptoms of wearing-off with rasagiline may be accompanied by improvement of executive functions, and further support the need for optimizing dopamine replacement therapy in fluctuating Parkinson's disease patients.

The regulation of cerebral blood flow (CBF) is a complex and tightly controlled function ensuring delivery of oxygen and nutrients and removal of metabolic wastes from brain tissue. Cerebral vasoreactivity (CVR) refers to the ability of the nervous system to regulate CBF according to metabolic demands or changes in the microenvironment. This can be assessed through a variety of nuclear medicine and imaging techniques and protocols. Several studies have investigated the association of CVR with physiological and pathological conditions, with particular reference to the relationship with cognitive impairment and cerebrovascular disorders (CVD). A better understanding of the interaction between CVR and cognitive dysfunction in chronic and particularly acute CVD could help improving treatment and rehabilitation strategies in these patients. In this paper, we reviewed current knowledge on CVR alterations in the context of acute and chronic CVD and cognitive dysfunction. Alterations in CVR and hemodynamics have been described in patients with both neurodegenerative and vascular cognitive impairment, and the severity of these alterations seems to correlate with CVR derailment. Furthermore, an increased risk of cognitive impairment progression has been associated with alterations in CVR parameters and hemodynamics. Few studies have investigated these associations in acute cerebrovascular disorders and the results are inconsistent; thus, further research on this topic is encouraged.

Lake Nemi was subjected to organic pollution in the 1970s due to domestic wastes, which led to a severe eutrophication process. Local authorities consequently planned a gradual waste diversion programme completed in 1990. Comparison between data on plant-associated invertebrates in the period of maximum eutrophication (1981/82) and twenty years after the total waste diversion (2001/02) was carried out with the aim of demonstrating the performance of this littoral community for the purpose of lake recovery assessment. Following the water clarity improvement characterizing the 2001/02 period, the macrophyte community displayed an amelioration in plant diversification, an enlargement of the colonized area, and an appearance of Charales, important bioindicators of oligotrophic conditions. In complete agreement with this new situation, the invertebrate fauna extended its colonization, and the species composition and quantitative structure changed completely. A considerable increase in species richness and diversity, and significant modifications of percentages and densities of bioindicator taxa (cladocerans, gastropods and acari) showed a very appreciable recovery, which can be defined as a phase of “oligotrophication”. This trophic state is closely related to nutrient reduction in the water and enhanced by a drift of organic materials from littoral to profundal bottoms. This was due to the remarkable water level reduction of about five meters which occurred in the lake in recent times.