Mitochondrial toxicity of aluminium nanoparticles in comparison to its ionic form on isolated rat brain mitochondria.

OBJECTIVES: The aim of this study was to evaluate the toxic effect of AlNPs on rat brain mitochondria and compare it with that of aluminium's ionic form. METHODS: Mitochondria were isolated from rat brain. Isolated mitochondria were treated with normal saline (Control) and different concentrations of aluminium ions (AlIs) and AlNPs (50, 100 and 200 µM). Then, the effect of AlNPs on electron transport chain complexes as well as various endpoints such as mitochondrial oxidative damage (reactive oxygen species, lipid peroxidation, glutathione, and protein carbonyl) and mitochondrial function were assessed. Also, apoptosis was evaluated by cytochrome c release, mitochondrial membrane potential and swelling. RESULTS: When compared to the control group, the exposure to AlNPs showed a marked elevation in oxidative stress markers and inhibition of complex III which was accompanied by disturbance in mitochondrial function. Also, AlNPs induced a significant collapse of mitochondrial membrane potential, mitochondrial swelling, and cytochrome c release. CONCLUSIONS: The comparison of mitochondrial toxicity markers between both forms of aluminium revealed that the toxic effect of AlNPs on isolated brain mitochondria was substantially greater than that that caused by AlIs, which can probably be ascribed to its higher reactivity (Tab. 1, Fig. 8, Ref. 45).

Effects of enriched environment on alterations in the prefrontal cortex GFAP- and S100B-immunopositive astrocytes and behavioral deficits in MK-801-treated rats.

A plethora of studies have indicated that enriched environment (EE) paradigm provokes plastic and morphological changes in astrocytes with accompanying increments of their density and positively affects the behavior of rodents. We also previously documented that EE could be employed to preclude several behavioral abnormalities, mainly cognitive deficits, attributed to postnatal N-methyl-d-aspartate (NMDA) receptor antagonist (MK-801) treatment, as a rodent model of schizophrenia (SCH) aspects. Given this, the current study quantitatively investigated the number of cells, presumed to be astrocytes, expressing two astroglia-associated proteins (S100B and glial fibrillary acidic protein (GFAP)) by immunohistochemistry in the prefrontal cortex (PFC), along with anxiety and passive avoidance (PA) learning behaviors by utilizing elevated plus maze (EPM) and shuttle-box tests, in MK-801-treated male wistar rats submitted to EE and non-EE rats. Following a treatment regime of sub-chronic MK-801 (1.0mg/kg i.p. daily for five consecutive days from postnatal day (P) 6), S-100B-positive cells and anxiety level were markedly increased, while the GFAP-positive cells and PA learning were notably attenuated. The trend of diminished GFAP-immunopositive cells and elevated S100B-immunostained cells in the PFC was reversed in the SCH-like rats by exposure of animals to EE, commencing from birth up to the time of experiments on P28-85. Additionally, EE exhibited an ameliorating effect on the behavioral abnormalities evoked by MK-801. Overall, present findings support that improper astrocyte functioning and behavioral changes, reminiscent of the many facets of SCH, occur consequential to repetitive administration of MK-801 and that raising rat pups in an EE mitigates these alterations.

Sex-specific restoration of MK-801-induced sensorimotor gating deficit by environmental enrichment.

Despite ample evidence of N-methyl-D-aspartate (NMDA) receptor dysfunction in schizophrenia, no study has addressed the effects of enriched environment (EE) on sensorimotor gating deficits induced by postnatal NMDA receptor blockade. We evaluated the effect of EE on sensorimotor gating (measured by prepulse inhibition, PPI), or on sensorimotor gating deficit induced by the NMDA receptor antagonist (+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine maleate (MK-801) in both sexes of Wistar rats. Rats were injected with MK-801 (1 mg/kg) on postnatal days (P) 6-10. EE was provided from birth up to the time of experiments on P28-30 or P58-60. PPI data were collected at three prepulse intensities and then averaged to yield global PPI. MK-801 treatment reduced PPI significantly in both sexes. While EE per se had no significant effect on PPI, it restored MK-801-induced PPI deficit only in male rats. An extended period of EE did not influence PPI deficit in female rats. Our results indicate that postnatal exposure to MK-801 may exert long-lasting effects on neuronal circuits underlying sensorimotor gating. Sex-specific modulation of such effects by EE suggests sexually dimorphic mechanisms are involved.

Knowledge and practices of health care workers and medical students towards universal precautions in hospitals in Mazandaran Province.

This study investigated knowledge of and practices towards universal precautions among 540 health care workers and medical students in 2 university hospitals in Mazandaran Province, Islamic Republic of Iran. Only 65.8% and 90.0% staff in the 2 hospitals and 53.5% of medical students had heard about universal precautions. Overall, there was a low understanding of precautions, except concerning disposal of sharps, contact with vaginal fluid, use of mask and gown or cleaning spilled blood. Health workers had difficulty distinguishing between deep body fluids and body secretions that are not considered infectious. Good practices were reported regarding hand-washing, disposal of needles, and glove, mask and gown usage.

Knowledge and practices of health care workers and medical students towards universal precautions in hospitals in Mazandaran Province

This study investigated knowledge of and practices towards universal precautions among 540 health care workers and medical students in 2 university hospitals in Mazandaran Province, Islamic Republic of Iran. Only 65.8% and 90.0% staff in the 2 hospitals and 53.5% of medical students had heard about universal precautions. Overall, there was a low understanding of precautions, except concerning disposal of sharps, contact with vaginal fluid, use of mask and gown or cleaning spilled blood. Health workers had difficulty distinguishing between deep body fluids and body secretions that are not considered infectious. Good practices were reported regarding hand- washing, disposal of needles, and glove, mask and gown usage