The N-methyl-d-aspartate (NMDA) type of glutamate receptor (NMDAR) plays central roles in normal and pathological neuronal functioning. We have examined the regulation of the NR1 subunit of the NMDAR ...in response to excessive activation of this receptor in in vitro and in vivo models of excitotoxicity. NR1 protein expression in cultured cortical neurons was specifically reduced by stimulation with 100 μm NMDA or glutamate. NMDA decreased NR1 protein amounts by 71% after 8 h. Low NMDA concentrations (≤ 10 μm) had no effect. NR1 down-regulation was inhibited by the general NMDAR antagonist DL-AP5 and also by ifenprodil, which specifically antagonizes NMDARs containing NR2B subunits. Arrest of NMDAR signaling with DL-AP5 after brief exposure to NMDA did not prevent subsequent NR1 decrease. Down-regulation of NR1 did not involve calpain cleavage but resulted from a decrease in de novo synthesis consequence of reduced mRNA amounts. In contrast, NMDA did not alter the expression of NR2A mRNA or newly synthesized protein. In neurons transiently transfected with an NR1 promoter/luciferase reporter construct, promoter activity was reduced by 68% after 2 h of stimulation with NMDA, and its inhibition required extracellular calcium. A similar mechanism of autoregulation of the receptor probably operates during cerebral ischemia, because NR1 mRNA and protein were strongly decreased at early stages of blood reperfusion in the infarcted brains of rats subjected to occlusion of the middle cerebral artery. Because NR1 is the obligatory subunit of NMDARs, this regulatory mechanism will be fundamental to NMDAR functioning.
The effects of the hydration mechanism on continental crust recycling are analyzed through a 2‐D finite element thermomechanical model. Oceanic slab dehydration and consequent mantle wedge hydration ...are implemented using a dynamic method. Hydration is accomplished by lawsonite and serpentine breakdown; topography is treated as a free surface. Subduction rates of 1, 3, 5, 7.5, and 10 cm/yr; slab angles of 30°, 45°, and 60°; and a mantle rheology represented by dry dunite and dry olivine flow laws have been taken into account during successive numerical experiments. Model predictions pointed out that a direct relationship exists between mantle rheology and the amount of recycled crustal material: the larger the viscosity contrast between hydrated and dry mantle, the larger the percentage of recycled material into the mantle wedge. Slab dip variation has a moderate impact on the recycling. Metamorphic evolution of recycled material is influenced by subduction style. TPmax, generally representative of eclogite facies conditions, is sensitive to changes in slab dip. A direct relationship between subduction rate and exhumation rate results for different slab dips; this relationship does not depend on the used mantle flow law. Thermal regimes predicted by different numerical models are compared to PT paths followed by continental crustal slices involved in ancient and recent subduction zones, making ablative subduction a suitable precollisional mechanism for burial and exhumation of continental crust.
To gain information on laboratory hygiene in contained-use laboratories, a method was developed to study the presence of microorganisms on laboratory equipment. Focusing detection on genetically ...modified organisms (GMOs) containing the universal M13 primer binding sites enabled the detection of a broad range of GMOs using a single PCR. Swabbing surfaces in three different contained-use laboratories led to detection of M13-containing PCR products in 26 out of 34 swabs. Most sequences (up to five per sample) were detected in swabs from the centrifuge and sink, followed by swabs taken from the bin and incubator (up to four sequences per sample). The obtained sequences varied in length from 171 nucleotides (nt) to 878 nt. In most cases, sequences were only partially similar to sequences published in GenBank. The lengths of the regions with high similarity varied from 94 nt to 795 nt, and these similarities ranged from 81% to 100%. Similarities with more than one sequence were commonly found, complicating the identification of detected sequences. Nonetheless, 84% of the detected sequences were actually handled in the laboratory at the time of sampling. This demonstrates that the method may be used as a quality control tool to assess the efficacy of decontamination and cleaning of commonly used surfaces, such as laboratory benches, freezer doors, and centrifuge rotors, without prior knowledge of the identity or characteristics of the GMOs.
Galantamine, currently used in Alzheimer's patients, has shown neuroprotection in hippocampal slices subjected to oxygenglucose deprivation. Here, we present an in vivo study to evaluate the ...potential neuroprotective effects of galantamine in a transient global cerebral ischemia model in gerbils. Three treatment protocols were used. In the pretreatment protocol, gerbils were treated before ischemia and for 3 consecutive days thereafter. Eight groups of animals were included: sham operation plus placebo, 10 mg/kg mecamylamine and 10 mg/kg galantamine, respectively; and ischemia plus placebo, 10 mg/kg mecamylamine, 1 mg/kg galantamine, and 10 mg/kg galantamine and 10 mg/kg mecamylamine plus galantamine, respectively. Postischemia protocols included three groups of animals: sham operation, ischemia plus placebo, and ischemia plus 10 mg/kg galantamine; substances were administered 3 or 6 h after ischemia and for 2 consecutive days thereafter. Pyramidal neurons surviving in the cornus ammonis 1 region of the hippocampus were evaluated 72 h after reperfusion, terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) histochemistry, caspase-3 and superoxide dismutase (SOD)-2 immunohistochemistries, and Western blottings were performed, and object placement tests were carried out. Galantamine significantly increased the number of living pyramidal neurons after ischemia-reperfusion injury. Galantamine significantly reduced TUNEL, active caspase-3, and SOD-2 immunoreactivity. The nicotinic antagonist mecamylamine blocked the protective effects of galantamine. The neuroprotective effects of galantamine were preserved even when first administered at 3 h postischemia. These results correlated with the performance in the object placement test. This study shows that galantamine provides in vivo neuroprotection and memory recovery against global cerebral ischemia, even when administration begins 3 h postischemia.
In 2009, four bathing sites in The Netherlands were monitored for potentially human pathogenic
Vibrio species to observe possible associations with environmental conditions and health complaints. ...Three slightly different enrichment procedures were used to isolate
Vibrio species with different growth requirements. Waters were generally positive for
Vibrio from May until October; median
Vibrio concentrations ranged from 4 to 383 MPN per litre (maximum 10
5 MPN per litre). Isolated
Vibrio species included
V. alginolyticus (50.6%) and
V. parahaemolyticus (8.5%) from bathing sites with salinities ranging between 2.8 and 3.5% and
V. cholerae non-O1/O139 (6.9%) from sites with salinities ranging between 0.007 and 0.08%. Although more samples were positive for
Vibrio at elevated water temperatures, a quantitative relation between
Vibrio numbers in water samples and the water temperature was not observed which may be explained by maximum water temperatures of 21
°C. Active surveillance yielded one case of a recreational water related
Vibrio infection.
V. cholerae non-O1/O139 was cultured from the patient's wound and the implicated recreational water; PFGE profiles of the water and patient isolates were not identical. The number of patients that contract a
Vibrio infection through exposure to Dutch recreational waters seems low, but may be underestimated. The common occurrence of
Vibrio species in these waters stresses the need for providing information on
Vibrio to risk groups to prevent infections.
In fish spas, clients may submerge their hands, feet or whole body in basins with Garra rufa fish, for dead skin removal. Skin infections may result from using these spas, transmitted from fish to ...clients, through either fish or water, or from client to client. The microbiological water quality was determined in 24 fish spas in 16 companies in the Netherlands through analysis of a single water sample per fish spa. Water samples were tested for the presence of Aeromonas spp., Vibrio spp.,Pseudomonas aeruginosa, nontuberculous mycobacteria,and faecal indicator bacteria by using standard culture methods. The majority of the examined fish spas contained Aeromonas spp. (n = 24), P. aeruginosa(n = 18), Vibrio spp. (n = 16) including V. cholerae non-O1/O139 and V. vulnificus, and several rapid growing Mycobacterium spp. (n = 23) including M. fortuitum, M.conceptionense, M. abscessus and M. chelonae. Faecal contamination of the fish spa water was low. Based on the detected concentrations of Aeromonas spp., Vibriospp., and P. aeruginosa, the detected Mycobacteriumspp., and the health implications of these bacteria, the health risk from using fish spas is considered limited for healthy people with an intact skin and no underlying disease.
The transport of viruses in unsaturated porous media has been a subject of great interest in recent years because of the enhanced removal of these microorganisms compared with saturated conditions. ...We studied the transport of bacteriophages MS2 and φX174, used as surrogate pathogenic viruses, at various water contents and solution chemistries in terms of pH and ionic strength (IS). The objective was to explore the interaction of viruses with the solid-water interfaces (SWI) and air-water interfaces (AWI) for a range of conditions. The experimental data were fitted with a transport model to determine the adsorption (attachment and detachment rate) parameters. Our results show that the retention of viruses in the soil column increases as water saturation decreases when the chemical conditions are favorable for adsorption (pH 7 and relatively high IS). Our analysis indicates that the enhanced retention of φX174 viruses at lower water contents is caused by increased attachment to the SWI and that retention by the AWI is not significant. Results obtained from a first series of experiments (pH 9 and low IS) showed insignificant attachment of MS2 viruses to both the SWI and the AWI. The MS2 breakthrough data for a second series of experiments (pH 7 and high IS) did not allow us to separate out the role of the AWI. Although attachment of MS2 viruses to the AWI cannot be ruled out in our experiments, we suspect that the increased retention of this phage under unsaturated condition was also due to enhanced attachment to the SWI. Increased attachment to the SWI under unsaturated conditions is attributed to increased mass transfer of viruses to the SWI due to a reduced diffusion length at lower water contents. Our results demonstrate that if there is any attachment to the AWI, it is reversible. When unfavorable conditions occur for attachment to the SWI, the attached viruses may be detached by moving solid-water-air contact lines (SWA).
Cerebral ischemia triggers a multitude of pathophysiological and biochemical events that separately affect the evolution of focal ischemia and, therefore, stroke treatment should logically employ all ...known neuroprotective agents. We hypothesized that a treatment combining nimodipine and citicoline might have a potential neuroprotective effect. To assess this idea, Sprague-Dawley rats underwent transient bilateral common carotid artery ligation with simultaneous middle cerebral artery occlusion for 60 min. Four treatment groups were established. Animals received either: a) saline (control group); b) intracarotid nimodipine infusion during 30 min in the ischemia-reperfusion (nimodipine group); c) i.p. postischemic citicoline injections once daily for 7 days (citicoline group); or d) intracarotid nimodipine bolus during ischemia-reperfusion plus i.p. postichemic citicoline injections (combination group). They were killed after either 7 or 3 days after reperfusion. In the first case, the volume of the infarcted tissue was studied by a stereological procedure and in the second case, in situ end-labeling of nuclear DNA fragmentation (TUNEL) and Bcl-2 expression were employed to determine the level of apoptosis. The infarct volume was significantly reduced in both the nimodipine and the citicoline treatment groups after 7 days of reperfusion; combination of both drugs produced an additive effect. After 3 days of reperfusion, the number of Bcl-2-positive neurons was significantly increased while that of TUNEL-positive cells significantly decreased at the infarct border in the combined-treatment animals. Our findings demonstrate a neuroprotective effect from an acute single dose of nimodipine during ischemia-reperfusion and prolonged post-ischemic treatment with citicoline in a model of focal cerebral ischemia. These results suggest that a possible mechanism of neuroprotective action would be mediated by increased Bcl-2 expression and decreased apoptosis within the boundary zone of the infarct together with neutralization of the ischemia-reperfusion injury.
Objectives:
This retrospective case review was performed to determine the facial function outcome of an end-to-side interposed donor grafting technique in patients who had a nonresponsive and ...partially injured facial nerve during a translabyrinthine approach for vestibular schwannoma resection.
Methods:
The study included patients with silent electrophysiological tests after partial injury of the facial nerve during translabyrinthine schwannoma resection surgery in a tertiary referral hospital. The patients underwent end-to-side interposed donor grafting as a facial nerve reinforcement technique, and we evaluated their facial function after 1 year of follow-up.
Results:
Four cases with intact preoperative facial function were included (3 men and 1 woman). All patients had a lack of electrical response from the facial nerve and partial anatomic injury after a translabyrinthine approach. An end-to-side interposed donor grafting technique was performed. The donor grafts used were the sural nerve (2 patients), superior vestibular nerve (1 patient), and greater auricular nerve (1 patient). All patients achieved a good House-Brackmann grade. Ocular adjuvant procedures were performed in all patients.
Conclusions:
Immediate repair of the facial nerve with an interposed donor graft may provide better facial function in patients who have no electrical response from a partially injured facial nerve after vestibular schwannoma surgery.
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