| 1. |
|
|
| 2. |
- Abbas, Abdul-Karim, 1959, et al.
(författare)
-
Bicarbonate-sensitive cysteine induced elevation of extracellular aspartate and glutamate in rat hippocampus in vitro
- 1997
-
Ingår i: Neurochemistry International. - 0197-0186. ; 30:3, s. 253-259
-
Tidskriftsartikel (refereegranskat)abstract
- The effect of different concentrations of cysteine (0.125, 0.25, 0.5 and 1 mM) on the net efflux of endogenous amino acids was studied by the incubation of rat hippocampal slices. Addition of cysteine (1 mM) in bicarbonate containing low K+ medium (5 min) selectively increased the basal net efflux of glutamate and aspartate by 370% and 396%, respectively. High K+ media (50 mM) containing cysteine (1 mM) evoked the net efflux of glutamate and aspartate by 1454% and 1019%, respectively. The corresponding effects in control slices without cysteine were 669% and 404%, respectively. No changes were observed on the concentrations of GABA, glutamine and taurine. The cysteine oxidation products, cysteine sulfinate (0.5 μM) and cystine (0.25 mM) were without effects. The effect of cysteine (0.5 mM) was dramatically reduced in media with no added bicarbonate/CO2. Thus, cysteine in a bicarbonate-sensitive manner selectively increases the extracellular concentration of excitotoxic amino acids in adult rat brain in vitro, possibly by interfering with the carrier-mediated glutamate uptake/ release
|
|
| 3. |
- Abbas, Abdul-Karim, 1959, et al.
(författare)
-
Bicarbonate-sensitive cysteine induced elevation of extracellular aspartate and glutamate in rat hippocampus in vitro
- 1997
-
Ingår i: Neurochemistry International. - 0197-0186. ; 30:3, s. 253-259
-
Tidskriftsartikel (refereegranskat)abstract
- The effect of different concentrations of cysteine (0.125, 0.25, 0.5 and 1 mM) on the net efflux of endogenous amino acids was studied by the incubation of rat hippocampal slices. Addition of cysteine (1 mM) in bicarbonate containing low K+ medium (5 min) selectively increased the basal net efflux of glutamate and aspartate by 370% and 396%, respectively. High K+ media (50 mM) containing cysteine (1 mM) evoked the net efflux of glutamate and aspartate by 1 454% and 1 019%, respectively. The corresponding effects in control slices without cysteine were 669% and 404%, respectively. No changes were observed on the concentrations of GABA, glutamine and taurine. The cysteine oxidation products, cysteine sulfinate (0.5 μM) and cystine (0.25 mM) were without effects. The effect of cysteine (0.5 mM) was dramatically reduced in media with no added bicarbonate/CO2. Thus, cysteine in a bicarbonate-sensitive manner selectively increases the extracellular concentration of excitotoxic amino acids in adult rat brain in vitro, possibly by interfering with the carrier-mediated glutamate uptake/ release
|
|
| 4. |
|
|
| 5. |
- Abbas, Abdul-Karim, 1959, et al.
(författare)
-
Emetine treatment masks initial LTP without affecting long-term stability.
- 2011
-
Ingår i: Brain research. - : Elsevier BV. - 1872-6240 .- 0006-8993. ; 1426, s. 18-29
-
Tidskriftsartikel (refereegranskat)abstract
- Applying emetine, a protein synthesis inhibitor, at 20-40μM for 90-120min prior to LTP induction in hippocampal slices from young rats (2-3weeks) and washing it out afterwards revealed a slowly developing potentiation that reached maximum after 20-30min, distinct from the LTP observed under normal conditions. Nevertheless, the later phase of this potentiation was similar to standard LTP as judged by experiments lasting up to 8h after induction. Emetine preapplication for 3h without subsequent washout resulted in a substantial decay of evoked responses. By comparison between test and control pathways, LTP could still be assessed in these experiments for up to 4-6h after induction and was found not to differ from normal, except for the slow onset. The NMDA-R blocker AP5 fully blocked LTP; however, with emetine pretreatment there was an initial depression of responses with a gradual recovery during 20-30min. This depression involved not only the field EPSP but also the presynaptic fiber volley. However, when using the protein synthesis inhibitors cycloheximide and anisomycin there was essentially no such depression. In conclusion, the present results support the idea that preexisting proteins are sufficient for inducing stable LTP. Moreover, emetine but not anisomycin or cycloheximide impairs presynaptic action potentials, leading to an apparent slow onset of LTP. The emetine-dependent effect could be due to a characteristic blocking spectrum of the drug, preferred targeting of presynaptic compartments or effects unrelated to protein synthesis.
|
|
| 6. |
- Abbas, Abdul-Karim, 1959
(författare)
-
Evidence based medicine: a critical inquiry. Seminar Lecture
- 2010
-
Ingår i: The 5th Annual Meeting of International Iraqi Medical Association, April 1-3, 2010, Sharjah, UAE.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Evidence-based medicine and practice (EBM/EBP) have since their inception in the early 1990s had widespread impact on the teaching and practice of medicine and health care. While the western societies are becoming more postmodernist, the medical system remains increasingly modernist in its outlook, this may make it increasingly irrelevant to the needs of a changing society. However, criticism is essentially a changing process of our realities. Hence, the prominence given to EBM can not be seen as a solely attempt to reassert modernism within the field, but as an improved paradigm reviewing itself in lights of challenges it faces. Relevant to my topic here is that the debate, which took sometimes, unfortunately, metaphorical and aggressive directions, has contributing effect on both the EBM and its critics moderating both methodologies and epistemes especially the introducing of other kinds of researches, than randomized controlled trails (RCT), systematic reviews or meta-analysis of RCTs, like user-led research and qualitative researches which focus on personal experience of both the patient and clinician. In the developing countries there are many challenges, whether technical, social or epistemological, facing practicing and using them. Although few Arab countries have recently developed either centers or associations for EBM, Iraq still lacks such kind of practice. Presenting an outlook of EMB from within the current intellectual debate and examining the environment and essential aspects of this debate between the EMB and its postmodernist critics might be helpful in not a merely dogmatic promotion of its practice nor a blind call for adopting and applying its guidelines and techniques but in enforcing the discussion and dialogue between the current disputable paradigms in the one hand and improve the possibilities and resources to use it as the “best” paradigm in medical practices and education. A conclusion has drawn on here that EBM paradigm does not only improve the decision-making in health services and provides a serious attempt to invent a new language that might reunite the Babel of doctors and patients, managers and consumers, but also it understands medical care in both the closed and open systems. Epistemological, methodological, ethical and social questions about the patient/subject are addressed here aiming to encourage the health and educational authorities in Iraq to take this paradigm seriously and introduce it in their future programs.
|
|
| 7. |
- Abbas, Abdul-Karim, 1959
(författare)
-
Evidence for constitutive protein synthesis in hippocampal LTP stabilization
- 2013
-
Ingår i: Neuroscience. - : Elsevier BV. - 0306-4522. ; 246, s. 301-311
-
Tidskriftsartikel (refereegranskat)abstract
- The notion that blockade of constitutive protein synthesis underlies the effect of protein synthesis inhibitors (PSIs) on long-term potentiation (LTP) stabilization was examined using the rat hippocampal CA3-CA1 synapse. Using a biochemical assay we found protein synthesis rate largely recovered 1h after wash-out of cycloheximide (CHX). Nonetheless, a 4-h CHX application followed by wash-out 1h prior to LTP resulted in a significant decrement of LTP stabilization. Wash-out initiated just prior to LTP, thus extending protein synthesis inhibition well into the post-LTP period, resulted in no further effect on LTP. However, short pre- and continuous post-tetanization application of PSIs failed to influence LTP persistence for up to 7h. Addition of hydrogen peroxide (H2O2) 5-25min following LTP induction resulted in parallel depression of potentiated and non-potentiated inputs, leaving LTP seemingly unaltered. However, in the presence of cyxloheximide the H2O2 application resulted in a significant reduction of LTP. In conclusion: LTP stabilization was impaired by pre-LTP application of protein synthesis inhibition but not by post-LTP application unless the slices were exposed to oxidative stress. We submit that these results favor the notion that constitutive rather than triggered protein synthesis is important for LTP stabilization.
|
|
| 8. |
|
|
| 9. |
- Abbas, Abdul-Karim, 1959
(författare)
-
Kainic Acid, NMDA and Bicuculline Induce Elevation in Concentrations of Glutathione and Amino Acids in Vivo: Biomarkers for Seizure Predisposition?
- 2015
-
Ingår i: Journal of Behavioral and Brain Science. - : Scientific Research Publishing, Inc.. - 2160-5866 .- 2160-5874. ; 5:5, s. 163-172
-
Tidskriftsartikel (refereegranskat)abstract
- The present study was carried out to investigate the effect of NMDA, bicuculline and kainic acid (KA) on the extracellular concentration of glutathione, phosphoethanolamine (PEA) and taurine in rat hippocampus in vivo. Rats were implanted with intrahippocampal microelectrodes perfused with free-glucose Krebs-Ringer solution and allowed to recover for about 2 h. After assaying baseline concentrations of amino acids, NMDA or bicuculline was administered intrahippocampally, whereas KA was given systemically. Either treatment resulted in significant high extracellular concentrations of glutathione, but only NMDA or KA resulted in high concentrations of PEA and taurine. Interestingly, the increase in glutathione concentration due to KA was followed by a delayed increase of glutamate and PEA. Our results demonstrated that increased efflux of glutathione, a common consequence of different neuroexcitotoxic agents, occurs in vivo. Given that the agents used in the present study were also convulsunts, the implication of the findings on seizure predisposition was also considered.
|
|
| 10. |
|
|
