NADP-dependent enzymes are involved in response to salt and hypoosmotic stress in cucumber plants.

Salt stress is one of the most damaging plant stressors, whereas hypoosmotic stress is not considered to be a dangerous type of stress in plants and has been less extensively studied. This study was performed to compare the metabolism of cucumber plants grown in soil with plants transferred to distilled water and to a 100 mM NaCl solution. Even though hypoosmotic stress caused by distilled water did not cause such significant changes in the relative water content, Na+/K+ ratio and Rubisco content as those caused by salt stress, it was accompanied by more pronounced changes in the specific activities of NADP-dependent enzymes. After 3 days, the specific activities of NADP-isocitrate dehydrogenase, glucose-6-phosphate dehydrogenase, NADP-malic enzyme and non-phosphorylating glyceraldehyde-3-phosphate dehydrogenase in leaves were highest under hypoosmotic stress, and lowest in plants grown in soil. In roots, salt stress caused a decrease in the specific activities of major NADP-enzymes. However, at the beginning of salt stress, NADP-galactose-1-dehydrogenase and ribose-1-dehydrogenase were involved in a plant defense response in both roots and leaves. Therefore, the enhanced demands of NADPH in stress can be replenished by a wide range of NADP-dependent enzymes.

A protocol based on hypotension probability indicator vs. standard care to prevent intraoperative hypotension during supratentorial brain surgery: a prospective randomized pilot trial.

BACKGROUND: To test the hypothesis that Hypotension probability indicator (HPI) driven hemodynamic protocol use may decrease the exposition to hypotension (mean arterial pressure below 65 mmHg) during supratentorial intracranial procedures. METHODS: Patients undergoing supratentorial tumor resection under general anesthesia (ASA 1-3) were included into this randomized single center-controlled pilot trial. Patients in the control group (COV, N.=20) were managed based on the institutional standard to avoid hypotension. Patients in the intervention (INT, N.=20) group were managed using a protocol triggered by the HPI above 85 based on the stroke volume variation, dynamic elastance, and cardiac index parameters. The number of patients experiencing hypotension (mean arterial pressure below 65 mmHg) during the whole procedure and anesthesia maintenance phase was the primary outcome variable. The number of hypotensive periods, time spent in hypotension, and hypotension dose served as secondary outcome variables. Other clinically relevant parameters and postsurgical outcomes were screened. RESULTS: The number of patients who never experienced hypotension was significantly lower in the INT group during the anesthesia maintenance phase (10 (50%) vs. 16 (80%); P=0.049). In several other hemodynamic outcomes, a distinct numerical, but statistically non-significant trend towards lower hypotension exposition was observed. There were no significant differences in clinically relevant parameters. CONCLUSIONS: In this pilot trial, the HPI-based protocol decreased the incidence of hypotension during the anesthesia maintenance but non-significant trends among secondary outcomes were also documented. Larger trials are needed to confirm our findings.

[The impact of neuroprotection on brain metabolism during carotid endarterectomy]. / Vliv neuroprotekce na mozkové metabolické parametry pri karotické endarterektomii.

BACKGROUND: The primary objective of this study was to evaluate the impact of neuroprotection, administered during carotid endarterectomy, on brain metabolism. The secondary objective was to assess the impact on clinical outcome of the resulting changes to brain metabolism. METHODS: A total of 35 patients underwent carotid endarterectomy with prophylactic combined neuroprotection (Sendai cocktail: Manitol, Phenhydan, Solumedrol, Tokoferol; Cerebrolysin; fraction of inspired oxygen (FiO2) = 1, middle arterial pressure (MAP) = 100 mm Hg, total intravenous anaesthesia--TIVA). The influence of neuroprotection on brain metabolism (S100B, glycaemia, lactate, pH, jugular vein bulb oxygen saturation--SvjO2) was evaluated. Metabolic parameters were acquired from the jugular bulb during surgery, just before unclamping of the vessel. The clinical outcome was evaluated by NIHSS (National Institutes of Health Stroke Scale). There were 35 patients in the control group who where operated on without any neuroprotection. The results from both groups of patients were compared and statistically analyzed. RESULTS: Postoperative NIHSS did not change in any patients in either group. An intraoperative shunt was not inserted in any patients in either group. In the group with neuroprotection there were significantly higher levels of S100B (median 0.117 vs. 0.088; p < 0.0182), lactate (median 1.92 vs. 1.020; p < 0.0006), glycaemia (median 9.5 vs. 8.2; p < 0.0243), and SvjO2 (median 0.79 vs. 0.65; p < 0.0001). There were no postoperative changes to NIHSS in either group. CONCLUSIONS: Neuroprotection administered before carotid endarterectomy influences some parameters of brain metabolism both positively and negatively, but with no impact on clinical outcome.

Mineralogical and geochemical controls of arsenic speciation and mobility under different redox conditions in soil, sediment and water at the Mokrsko-West gold deposit, Czech Republic.

Naturally contaminated soil, sediment and water at the Mokrsko-West gold deposit, Central Bohemia, have been studied in order to determine the processes that lead to release of As into water and to control its speciation under various redox conditions. In soils, As is bonded mainly to secondary arseniosiderite, pharmacosiderite and Fe oxyhydroxides and, rarely, to scorodite; in sediments, As is bonded mainly to Fe oxyhydroxides and rarely to arsenate minerals. The highest concentrations of dissolved As were found in groundwater (up to 1141 microg L(-1)), which mostly represented a redox transition zone where neither sulphide minerals nor Fe oxyhydroxide are stable. The main processes releasing dissolved As in this zone are attributed to the reductive dissolution of Fe oxyhydroxides and arsenate minerals, resulting in a substantial decrease in their amounts below the groundwater level. Some shallow subsurface environments with high organic matter contents were characterized by reducing conditions that indicated a relatively high amount of S(-2,0) in the solid phase and a lower dissolved As concentration (70-80 microg L(-1)) in the pore water. These findings are attributed to the formation of Fe(II) sulphides with the sorbed As. Under oxidizing conditions, surface waters were undersaturated with respect to arsenate minerals and this promoted the dissolution of secondary arsenates and increased the As concentrations in the water to characteristic values from 300 to 450 microg L(-1) in the stream and fishpond waters. The levels of dissolved As(III) often predominate over As(V) levels, both in groundwaters and in surface waters. The As(III)/As(V) ratio is closely related to the DOC concentration and this could support the assumption of a key role of microbial processes in transformations of aqueous As species as well as in the mobility of As.