Asmaa ALALI - Academia.edu (original) (raw)
Uploads
Papers by Asmaa ALALI
PLoS ONE, 2010
Background: Associative high-frequency electrical stimulation (HFS) of the supraorbital nerve in ... more Background: Associative high-frequency electrical stimulation (HFS) of the supraorbital nerve in five healthy individuals induced long-term potentiation (LTP)-like or depression (LTD)-like changes in the human blink reflex circuit according to the rules of spike timing-dependent plasticity (Mao and Evinger, 2001). HFS given at the onset of the R2 component of the blink reflex (HFS LTP) produced a lasting facilitation of the R2, whereas HFS given shortly before R2 (HFS LTD) caused a lasting suppression of the R2. In patients with benign essential blepharospasm (BEB), a focal dystonia affecting the orbicularis oculi muscles, HFS LTP induced excessive LTP-like associative plasticity relative to healthy controls, which was normalized after botulinum toxin (BTX) injections (Quartarone et al, 2006). Methodology/Principal Findings: We used HFS conditioning of the supraorbital nerve to study homeostatic metaplasticity of the blink reflex circuit in healthy subjects and dystonic patients. On separate days, we tested the conditioning effects on the R2 response and paired-pulse R2 inhibition after (i) HFS LTP , (ii) HFS LTP followed by HFS LTP , and (iii) HFS LTP followed by HFS LTD. Controls also received (iv) HFS LTD alone and (v) a non-intervention protocol. In BEB patients, HFS LTP followed by HFS LTD was given before and after BTX treatment. We were not able to replicate the bidirectional timing-dependent effects of HFS LTP and HFS LTD alone. All HFS protocols produced a non-specific reduction of the R2 response and a relative decrease in paired-pulse inhibition. These R2 changes also occurred in controls when no HFS was applied. There was also no trace of a homeostatic response pattern in BEB patients before or after BTX treatment. Conclusion/Significance: Our data challenge the efficacy of associative HFS to produce bidirectional plasticity in the human blink reflex circuit. The non-specific decrease of the R2 response might indicate habituation of the blink reflex following repeated electrical supraorbital stimulation. The increase of inhibition after paired pulse stimulation might reflect homeostatic behaviour to prevent further down regulation of the R2 response to preserve the protection of this adverseeffects reflex.
A number of organo-selenium compounds have been planned and synthesized for pharmacological prope... more A number of organo-selenium compounds have been planned and synthesized for pharmacological properties. A novel selena-diazole derivative compound[ 4', 4"(4, 5, 6, 7Tetrahydro[1, 2, 3-] Selenadiazolo [4, 5e] Pyridine-4, 6-Diyl) Bis (Benzene-1, 3-Diol)] (SeD) was previously synthesized, identified.The main objective of the current study is the study of some of its pharmacological effects; include hematological profile, T and B lymphocytes count, effects on prothrombin time; also, SeD activity on thyroid hormone. Two groups of Wister female Rats, Control group (NS) and the second Test (SeD) group received a daily dose of 50 mg/Kg BW for one month. Complete Blood cell count; Deferential Lymphocytes count; Serum Thyroid hormones were evaluated; also, vitro Prothrombin Time (PT) international normalized ratio (INR) and activated partial thromboplastin time (a PTT) were estimated. The results indicate that a significantly increase in WBC and Lymphocytes%. While Granulocytes and b...
PLoS ONE, 2010
Background: Associative high-frequency electrical stimulation (HFS) of the supraorbital nerve in ... more Background: Associative high-frequency electrical stimulation (HFS) of the supraorbital nerve in five healthy individuals induced long-term potentiation (LTP)-like or depression (LTD)-like changes in the human blink reflex circuit according to the rules of spike timing-dependent plasticity (Mao and Evinger, 2001). HFS given at the onset of the R2 component of the blink reflex (HFS LTP) produced a lasting facilitation of the R2, whereas HFS given shortly before R2 (HFS LTD) caused a lasting suppression of the R2. In patients with benign essential blepharospasm (BEB), a focal dystonia affecting the orbicularis oculi muscles, HFS LTP induced excessive LTP-like associative plasticity relative to healthy controls, which was normalized after botulinum toxin (BTX) injections (Quartarone et al, 2006). Methodology/Principal Findings: We used HFS conditioning of the supraorbital nerve to study homeostatic metaplasticity of the blink reflex circuit in healthy subjects and dystonic patients. On separate days, we tested the conditioning effects on the R2 response and paired-pulse R2 inhibition after (i) HFS LTP , (ii) HFS LTP followed by HFS LTP , and (iii) HFS LTP followed by HFS LTD. Controls also received (iv) HFS LTD alone and (v) a non-intervention protocol. In BEB patients, HFS LTP followed by HFS LTD was given before and after BTX treatment. We were not able to replicate the bidirectional timing-dependent effects of HFS LTP and HFS LTD alone. All HFS protocols produced a non-specific reduction of the R2 response and a relative decrease in paired-pulse inhibition. These R2 changes also occurred in controls when no HFS was applied. There was also no trace of a homeostatic response pattern in BEB patients before or after BTX treatment. Conclusion/Significance: Our data challenge the efficacy of associative HFS to produce bidirectional plasticity in the human blink reflex circuit. The non-specific decrease of the R2 response might indicate habituation of the blink reflex following repeated electrical supraorbital stimulation. The increase of inhibition after paired pulse stimulation might reflect homeostatic behaviour to prevent further down regulation of the R2 response to preserve the protection of this adverseeffects reflex.
A number of organo-selenium compounds have been planned and synthesized for pharmacological prope... more A number of organo-selenium compounds have been planned and synthesized for pharmacological properties. A novel selena-diazole derivative compound[ 4', 4"(4, 5, 6, 7Tetrahydro[1, 2, 3-] Selenadiazolo [4, 5e] Pyridine-4, 6-Diyl) Bis (Benzene-1, 3-Diol)] (SeD) was previously synthesized, identified.The main objective of the current study is the study of some of its pharmacological effects; include hematological profile, T and B lymphocytes count, effects on prothrombin time; also, SeD activity on thyroid hormone. Two groups of Wister female Rats, Control group (NS) and the second Test (SeD) group received a daily dose of 50 mg/Kg BW for one month. Complete Blood cell count; Deferential Lymphocytes count; Serum Thyroid hormones were evaluated; also, vitro Prothrombin Time (PT) international normalized ratio (INR) and activated partial thromboplastin time (a PTT) were estimated. The results indicate that a significantly increase in WBC and Lymphocytes%. While Granulocytes and b...