Search results

1

Role of iron in pathogenesis of Parkinson disease

100%

Gałązka-Friedman J., Friedman A.

BioTechnologia

|

2011

|

issue 2

2

Controversies about iron in parkinsonian and control substantia nigra

100%

Galazka-Friedman J., Friedman A.

Acta Neurobiologiae Experimentalis

|

1997

|

vol. 57

|

issue 3

217-225

EN

According to the oxidative stress theory iron may play an important role in the pathogenesis of neurodegenerative diseases, as e.g. Parkinson's disease (PD). This review presents the results of studies, obtained by various methods, of iron in substantia nigra (SN) - a cerebral structure which degenerates in PD - and shows controversies concerning the amount of iron, its redox state, and the iron binding compounds. Taking into account all published experimental results, the increase in the concentration of iron in parkinsonian SN vs. control may be estimated as (3 + - 5)%. The presence of large amounts of divalent iron in post mortem SN can be unequivocally negated. It is, however, still possible that iron is involved in the pathogenesis of PD, as even minor changes in the amount and form of iron may initiate processes leading to cells death.

3

Role of iron in pathogenesis of Parkinson disease

100%

Galazka-Friedman J., Friedman A.

Biotechnologia

|

2011

|

issue 2

153-158

EN

Parkinson's disease is one of the most frequent human neurodegenerations. Motor symptoms of Parkinson's disease are the consequence of the destruction of nervous cells in the substantia nigra (SN), a small (about 500 mg) structure located deep in human brain. The concentration of iron in SN is comparable to that in liver and is equal to about 180 ? 60 ng/mg of wet tissue and the iron in SN is mostly bound to ferritin. For many years it has been believed that the degeneration of nervous cells in SN in Parkinson's disease is related to an important increase in the concentration of iron. Our own studies based on M?ssbauer spectroscopy and other studies conducted with the use of various techniques have not confirmed this finding. The ratio of the concentration of iron in PD vs. control SN evaluated by Mossbauer spectroscopy was found to be equal 1.00?0.13. We also confirmed that most of iron in SN is located within ferritin. ELISA studies demonstrated a significant decrease in L ferritin in parkinsonian SN compared to the control group. As L-ferritin is related to safe keeping of iron within the ferritin shell, its decrease may lead to an efflux of iron and increase in the concentration of labile iron. Indeed our studies did show a difference in the concentration of labile iron between PD and control SN (135 +- 10 ng/g vs. 76 +- 5 ng/g). This labile iron, which may initiate Fenton reaction, may be the cause of the oxidative stress leading to the death of nervous cells in PD.

4

Generation of Intense Free-Electron Laser Radiation in the Terahertz Regime

81%

Pinhasi Y., Lurie Y., Pinhasi G., Friedman A.

Acta Physica Polonica A

|

2015

|

vol. 128

|

issue 3

315-318

EN

Free-electron lasers are high power radiation sources that utilize a distributed interaction between an accelerated electron beam and the electromagnetic field. In these devices, the electron beam serves as the amplification medium generating electromagnetic radiation, while propagating in a periodic magnetic structure called "wiggler" or "undulator". When electrons pass in the wiggler, they oscillate and act as a moving dipole emitting a wave packet of undulator synchrotron radiation. Incoherent summation of the wave packets results in a spontaneous emission. When the electrons are bunched into a short pulse, they all emit their wave packets in the same phase. The radiation wave packets combine coherently, resulting in super-radiance (where the energy radiated is proportional to the square of the electric charge). Such short bunches can be generated by an RF linear accelerator, driven by a photocathode injector. The radiation wavelength is determined by the velocity of the electrons and the spatial period of the undulator. The super-radiance mechanism enables the generation of intense radiation in frequency bands, whereas conventional sources fail to produce a powerful coherent radiation. In this article, we describe the design and analysis of ultrashort pulse free-electron laser operating at the sub-millimeter and terahertz regimes. The free-electron laser is based on a magnetostatic planar wiggler, in which super-radiant emission is emanated by accelerated electron bunches. A three-dimensional, space-frequency theory is developed in order to study radiation excitation in the wiggler. The total electromagnetic field (radiation and space-charge waves) is presented in the frequency domain as an expansion in terms of transverse eigenmodes of the (cold) cavity, in which the field is excited and propagates. The mutual interaction between the electron beam and the electromagnetic field is fully described by coupled equations, expressing the evolution of mode amplitudes and electron beam dynamics. The approach is applied in a numerical particle code WB3D, simulating wide-band interaction of a free-electron laser operating in the linear and non-linear regimes. The model is utilized to study spontaneous and super-radiant emissions radiated by an electron bunch at the sub-millimeter regime, taking into account three-dimensional space-charge effects emerging in such ultrashort bunches.

5

T1 and T2 Relaxation Times from Substantia Nigra in Parkinson's Disease and Control

81%

Kuliński R., Szlachta K., Gałązka-Friedman J., Friedman A.

|

vol. 125

|

issue 4

869-871

EN

The diagnosis of Parkinson's disease, and also other neurodegenerative disorders, is based on clinical examination. Many attempts are undertaken to find a test that could confirm this clinical diagnosis. Many hopes were attributed to magnetic resonance imaging but its importance remains obscure. The aim of this study was to compare T1 and T2 relaxation times from substantia nigra of patients with clinical diagnosis of Parkinson's disease and age-matched controls. A decrease of T2 (54.5 ± 1.4 ms vs. 58.0 ± 1.5 ms) in Parkinson's disease vs. control was found with confidence level of 5%. T1 did not differ significantly between Parkinson's disease and control (624 ± 17 ms vs. 614 ± 21 ms).

6

Different Signals of Magnetic Resonance Imaging and Ultrasound from Substantia Nigra in Parkinson's Disease and Control - Is Iron the Cause?

71%

Szlachta K., Sadowski K., Kuliński R., Gałązka-Friedman J., Friedman A.

Acta Physica Polonica A

|

2012

|

vol. 121

|

issue 2

454-456

EN

Motor symptoms of Parkinson's disease are caused by a progressive degeneration of substantia nigra, a small structure located deep in the brain. The cause of this process is unknown but may be related to iron mediated oxidative stress. The aim of this study was to understand the mechanism of the change of magnetic resonance and ultrasound signals found in patients with Parkinson's disease, which were attributed by several authors to an important increase of the concentration of iron in substantia nigra. USG and MRI measurements were performed on phantoms simulating human brain to which high amounts of iron were introduced. The USG signal was unaffected by insertion of iron-loaded ferritin, while it was by insertion of glial tissue. Injections of iron-loaded ferritin and iron ions to the phantoms decreased T_2 relaxation time. Our results suggest that the observed change of the signal from Parkinsonian brains is probably due to a proliferation of glia and not to an increase of the concentration of iron.

7

Mössbauer Studies of Pathological Brain Tissues Affected by PSP Disease

61%

Gałązka-Friedman J., Bauminger E., Szlachta K., Schweitzer K., Wszolek Z., Dickson D., Friedman A.

Acta Physica Polonica A

|

2009

|

vol. 115

|

issue 2

545-547

EN

Progressive supranuclear palsy (PSP) is a neurological disease leading to the damage of two brain structures: globus pallidus and substantia nigra. The pathomechanism of this disease is still unknown. One of the hypotheses is oxidative stress. Oxidative stress is an overproduction of free radicals in which iron may be involved. To verify the hypothesis that iron may play a role in PSP we performed the Mössbauer comparative studies of pathological and control tissues. Ten samples of PSP globus pallidus, ten samples of PSP substantia nigra, twelve control samples of globus pallidus and nine control samples of substantia nigra were measured in a conventional Mössbauer spectrometer at 90 K. The Mössbauer spectra obtained for all samples showed well resolved doublets with an isomer shift of 0.46±0.01 mm/s and a quadruple splitting of 0.70±0.02 mm/s. The main difference in these preliminary studies was in the concentration of iron. The concentration in PSP samples in globus pallidus was found to be 257±19 ng/mg tissue, compared to 183±22 ng/mg in control samples and 301±26 ng/mg in substantia nigra compared to 188±22 ng/mg in control samples. Taking into consideration that we did not notice any substantial increase in iron concentration in Parkinsonian substantia nigra compared to control substantia nigra, but a substantial increase in both substantia nigra and globus pallidus in PSP, may suggest that iron plays a different role in the pathomechanisms of PSP and of Parkinson's disease.

8

Nonverbal deficits in explicit and implicit memory of Parkinson's disease patients

61%

Gawrys L., Szatkowska I., Jamrozik Z., Janik P., Friedman A., Kaczmarek L.

Acta Neurobiologiae Experimentalis

|

2008

|

vol. 68

|

issue 1

58-72

EN

This study examined verbal and nonverbal aspects of explicit and implicit memory in a sample of 19 Parkinson's disease (PD) patients and 21 control subjects. For implicit memory evaluation, we used a Mirror Reading (MR) task employing verbal material as well as a nonverbal Serial Reaction Time (SRT) task. For explicit memory measurement we applied a word pairs task (verbal) and pairs of a Japanese ideograms task (nonverbal). The PD patients displayed impairments in the nonverbal tasks only, namely, in the SRT task and the pairs of Japanese ideograms task. No correlation between Wisconsin Card Sorting Test (WCST) scores and the results of tasks in which PD patients displayed deficits (SRT and pairs of Japanese ideograms) were discovered. Interestingly, such a correlation was found in the case of MR and words pairs tasks, which did not distinguish PD patients from control group.

9

Iron in Alzheimer's and Control Hippocampi - Mössbauer, Atomic Absorption and ELISA Studies

52%

Gałązka-Friedman J., Bauminger E., Szlachta K., Koziorowski D., Tomasiuk R., Jaklewicz A., Wszołek Z., Dickson D., Kaplińska K., Friedman A.

Acta Physica Polonica A

|

2011

|

vol. 119

|

issue 1

81-83

EN

Alzheimer disease is a neurodegenerative process of unknown mechanism taking place in a part of the brain - hippocampus. Oxidative stress and the role of iron in it is one of the suggested mechanisms of cells death. In this study several methods were used to assess iron and iron binding compounds in human hippocampus tissues. Mössbauer spectroscopy was used for identification of the iron binding compound and determination of total iron concentration in 12 control and one Alzheimer disease sample of hippocampus. Mössbauer parameters obtained for all samples suggest that most of the iron is ferritin-like iron. The average concentration of iron determined by Mössbauer spectroscopy in control hippocampus was 45±10 ng/mg wet tissue. The average concentration of iron in 10 Alzheimer disease samples determined by atomic absorption was 66±13 ng/mg wet tissue. The concentration of H and L chains of ferritin in 20 control and 10 AD hippocampi was assessed with enzyme-linked immuno-absorbent assay. The concentration of H and L ferritin was higher in Alzheimer disease compared to control (19.36±1.51 vs. 5.84±0.55 ng/μg protein for H, and 1.39±0.25 vs. 0.55±0.10 for L). This 3-fold increase of the concentration of ferritin is accompanied by a small increase of the total iron concentration.

Refine search results

Role of iron in pathogenesis of Parkinson disease

Controversies about iron in parkinsonian and control substantia nigra

Role of iron in pathogenesis of Parkinson disease

Generation of Intense Free-Electron Laser Radiation in the Terahertz Regime

T1 and T2 Relaxation Times from Substantia Nigra in Parkinson's Disease and Control

Different Signals of Magnetic Resonance Imaging and Ultrasound from Substantia Nigra in Parkinson's Disease and Control - Is Iron the Cause?

Mössbauer Studies of Pathological Brain Tissues Affected by PSP Disease

Nonverbal deficits in explicit and implicit memory of Parkinson's disease patients

Iron in Alzheimer's and Control Hippocampi - Mössbauer, Atomic Absorption and ELISA Studies