Biomedical subjects

S Giraudo

Publications and source records attributed to S Giraudo.

8 recordsLinked to original sources

PubMed2003

Proteome analysis of mesencephalic tissues: evidence for Parkinson's disease.

Proteome analysis is a powerful methodology to investigate protein expression in tissues involved in diseases not linked to particular genetic defects. To date, this technique has a limited number of applications in the field of neurodegenerative disorders. We decided therefore to investigate by this approach autoptic mesencephalic tissues of patients with idiopathic Parkinson's disease as well as control specimens from healthy subjects.

Blotting, Western↗

PubMed2002

Magnetic investigations of human mesencephalic neuromelanin.

Pigmentation of neurons in substantia nigra is due to neuromelanin, a pigment that stores large amounts of iron. Human mesencephalic neuromelanin has been investigated by means of magnetic susceptibility measurements as a function of temperature. Magnetic measurements provide a physico-chemical characterization of the iron cluster buried in the organic melanin matrix and support the view that iron is not simply chelated, but rather is organized in a three-dimensional network. The paramagnetism of isolated iron ions is observed, in agreement with electron paramagnetic resonance spectroscopy. Furthermore, antiferromagnetic grains with a large size distribution function are present. These grains contain N spins coupled antiferromagnetically; however, N(1/2) spins are decoupled from the grain bulk and parallelly aligned. The latter subgrains are superparamagnetic with a blocking temperature ranging between 5 K and room temperature. This behavior has not been observed in synthetic melanin, where the paramagnetic contribution is strongly enhanced. Preliminary results on pigment isolated from patients affected by Parkinson's disease, a neurodegenerative pathology involving primarily pigmented neurons in substantia nigra pars compacta, show a lower total magnetization compared to control neuromelanin. The temperature behavior of zero field cooling and field cooling magnetizations is similar for both. The significant depletion of iron content in Parkinson's disease neuromelanin could indicate a progressive Fe migration from its storage environment to the cytosol.

Ferric Compounds↗

PubMed2001

[Aid tool for the assessment of health measures performance: the example of the program for alcoholism prevention in Lorraine].

From "alcohol primary prevention program in Lorraine", the authors developed a tool for an evaluation of performance: a card index to assess each action of the program. This tool can be applied to various programs, in particular health regional ones. Before presenting the tool, the authors specify conceptual frameworks to which they refer and present the evaluation of performance step which is declined in "evaluation of the results" and "evaluation of the processes". This assessment combine an understanding and a data based approaches. They show how those two kinds of assessment meet different and complementary aims. The tool presented includes 9 cards. The first 8 cards joined together in a booklet make possible a description and evaluation of each contributive action to the program. A ninth card gives a synthesis view to follow and assess the entire program in comparison with the starting reference frame. The publication of this perfectible tool is a call to practices exchanges between professionals in load of health programs.

Alcoholism↗

PubMed2000

Q-band EPR investigations of neuromelanin in control and Parkinson's disease patients.

New insights into the understanding of the changes induced in the iron domain of neuromelanin (NM) upon development of Parkinson's disease (PD) have been gained by electron paramagnetic spectroscopy (EPR). The results of this study are compared with a previously reported variable temperature analysis of X-band EPR spectra of a NM specimen obtained from control brain tissues. The availability of high sensitivity instruments operating in the Q-band (34.4 GHz) allows us to deal with the low amounts of NM available from PD brains. The organization of iron in NM is in the form of polynuclear superparamagnetic/antiferromagnetic aggregates, but the lack of one or more signals in the EPR spectra of NM from PD suggests that the development of the pathology causes NM to decrease its ability to bind iron. Furthermore, the detection of the Mn(II) signal in the Q-band spectra is exploited as an additional internal probe to assess minor structural differences in iron domains of PD and control NM specimens.

Aged↗

PubMed2000

Isolation and 13C-NMR characterization of an insoluble proteinaceous fraction from substantia nigra of patients with Parkinson's disease.

Neuromelanin is a dark brown pigment suspected of being involved in the pathogenesis of Parkinson's disease. This pigment can be isolated from normal human substantia nigra by a procedure that includes an extensive proteolytic treatment. In this study we used such a procedure to extract the neuromelanin pigment from a pool of substantia nigra from patients affected by Parkinson's disease. 13C Cross polarization magic angle spinning nuclear magnetic resonance spectroscopy and electron paramagnetic resonance spectroscopy were used to characterize the solid residue obtained from the extraction procedure. We found that the pigment extracted from the substantia nigra of parkinsonian patients was mainly composed of highly cross-linked, protease-resistant, lipo-proteic material, whereas the neuromelanin macromolecule appears to be only a minor component of this extract. A synthetic model of melanoprotein has been prepared by enzymatic oxidation of dopamine in the presence of albumin. Once it has undergone the same proteolytic treatment, this model system yields a 13C-NMR spectrum which is similar to that observed for the parkinsonian midbrain extract. These results are consistent with the view that oxidative stress has a relevant role in the pathogenesis of Parkinson's disease.

Aged↗

PubMed2000

Nuclear magnetic relaxation dispersion profiles of substantia nigra pars compacta in Parkinson's disease patients are consistent with protein aggregation.

Nuclear Magnetic Relaxation field-cycling relaxometry is a technique, able to report on water mobility in tissues. By means of this technique, post-mortem specimens from both controls and idiopathic Parkinson's disease patients have been investigated. Results show different relaxometric behavior between the groups, which is consistent with protein aggregation in Parkinson's disease specimens.

Adult↗

PubMed1999

A novel 19F-NMR method for the investigation of the antioxidant capacity of biomolecules and biofluids.

A new assay for the measurement of the antioxidant capacity of biomolecules by high resolution 19F-NMR spectroscopy is presented here. This method is based on the use of trifluoroacetanilidic detectors, namely trifluoroacetanilide, N-(4-hydroxyphenyl)-trifluoroacetamide and 2-hydroxy-4-trifluoroacetamidobenzoic acid. Upon hydroxyl radical attack, such fluorinated detectors yield trifluoroacetamide and trifluoroacetic acid that can be quantitatively determined by 19F-NMR spectroscopy. Trifluoroacetamide was found to be a reliable reporter of hydroxyl radical attack on the fluorinated detectors, whereas N-(4-hydroxyphenyl)-trifluoroacetamide was found to be the most sensitive detector amongst the ones considered. Therefore, N-(4-hydroxyphenyl)-trifluoroacetamide has been used in competition experiments to assess the antioxidant capacity of a number of low and high molecular weight antioxidants. The antioxidant capacity of a given compound has been scaled in terms of an adimensional parameter, kF, that represents the ratio between the scavenger abilities of the fluorinated detector and the competitor. kF values obtained for low-molecular-mass compounds fall in the range 0.17 < kF < 1.5 and are in good agreement with second order rate constants (k2OH) for the reaction of the antioxidant with hydroxyl radicals. The kF value for serum albumin is much larger (46.9) than that predicted from the reported k2OH value. This finding supports the view that the protein can very effectively scavenge hydroxyl radicals as well as secondary radicals. Human blood serum showed that its antioxidant capacity is even higher than that shown by aqueous solutions of albumin at physiologic concentration suggesting a further contribution from other macromolecular serum components.

Antioxidants↗

PubMed1999

Cervical positional effects on snoring and apneas.

We examined the effects of cervical position on the Obstructive Sleep Apnea Syndrome (OSAS) through the use of a custom-designed cervical pillow which promoted neck extension. Twelve subjects with OSAS were recruited from a tertiary sleep disorder clinic population. Of the twelve subjects, three had mild cases of OSAS, four had moderate cases, and the remaining five had severe cases. The subjects used their usual pillows during two consecutive recorded baseline nights in our laboratory. The subjects then used the cervical pillow for five days at home, and returned for two consecutive recorded nights at our laboratory while using the cervical pillow. During the nights in our laboratory, the subjects completed questionnaires, were videotaped to record head and body position, and had their breathing parameters recorded during sleep. Subjects with mild OSAS cases had a non-significant improvement in the severity of their snoring and a significant improvement in their respiratory disturbance index with the cervical pillow, while subjects with moderate OSAS cases showed no improvement in these parameters. Subjects with severe OSAS cases showed slight improvement in some measures of their abnormal respiratory events during the experimental period.

Adult↗