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Biomedical subjects

P Gras

Publications and source records attributed to P Gras.

At least 19 recordsLinked to original sources
PubMed2006

[Finnish amyloid polyneuropathy in a French patient].

INTRODUCTION: Finnish amyloid variety is a rare familial amiloidosis polyneuropathy essentially observed in Finland. It concerns about six hundred people in the world in which five hundred reside in Finland. OBSERVATION: We report a case of a 58-year-old French woman with a 10-year history of lattice cornea dystrophy. She consulted in January 2004 for impaired swallowing, facial paralysis principally of the right superior territory and symptoms of arthritis which had developed a few months earlier. Observation revealed facial cutis laxa, tongue amyotrophy and some fasciculation. Electroneuromyography showed chronic neurogenic involvement of the facial muscles. Limbs and the sympathetic neuronal system were free of involvement. Pathological examination revealed areas of peri vascular amiloid deposits. Molecular biology confirmed the diagnosis of Finnish amiloidosis: substitution of aspartic acid by tyrosine in the 187 codon in the 9th chromosome (gelsoline gene). This mutation has been previously found in Denmark and the Czech Republic. CONCLUSION: Finnish amiloidosis is a familial polyneuropathy characterized by an association of cornea lattice dystrophy, cutis laxa and a chronic neurogenic involvement of the cranial nerves. Two mutations are known. Life expectancy is not affected, but quality of life is altered.

Amyloid Neuropathies, Familial↗
PubMed2002

Model based prediction of the clogging of an anaerobic fixed bed reactor.

This paper presents the use of nonlinear constrained optimization techniques in order to detect and evaluate the degree of clogging in an anaerobic fixed bed reactor. First, experimental results show that the validity of a mass balance model can degrade over the time. Using the available model of the process and nonlinear constrained optimization tools, it is established that these changes can be due to the decrease of the liquid volume into the reactor while the mean values of biomass concentrations increase, leading to the clogging of the reactor. These theoretical results are confirmed experimentally in evaluating the hydraulic retention time of the reactor using a tracer.

Anaerobiosis↗
PubMed2002

Evaluation of a four year experience with a fully instrumented anaerobic digestion process.

For several years, a 1 m3 fixed bed anaerobic digestion process has been operated for the treatment of distillery vinasses. This reactor has been fully instrumented with the following variables available on-line: pH, temperature, liquid and gas flow rates, gas composition (i.e., CH4, CO2 and H2), concentration of bicarbonate, chemical oxygen demand, total organic carbon, volatile fatty acids and partial and total alkalinity, these last four variables being measured twice by different techniques (i.e., using a TOC analyzer, a titrimetric sensor and an infrared spectrometer). The purpose of this paper is to compare the respective benefits of advanced instrumentation for the monitoring of wastewater treatment processes in general, and for anaerobic digestion in particular. It will also provide some statistical analysis of the time required to operate a fully instrumented wastewater treatment process. It is indeed well admitted in the literature that instrumentation is usually the main limitation step for using closed-loop control. However, it is our opinion that, in the near future, this situation will change. This point is discussed based on our four years practical experience.

Anaerobiosis↗
PubMed2002

On-line measurements of COD, TOC, VFA, total and partial alkalinity in anaerobic digestion processes using infra-red ectrometry.

This paper describes the use of a Fourier Transform Infra-Red (FT-IR) spectrometer as an on-line sensor to measure Chemical Oxygen Demand (COD), Total Organic Carbon (TOC), Volatile Fatty Acids (VFA), and Partial and Total Alkalinity (PA and TA) in anaerobic digestion processes for the treatment of industrial wastewaters. Comparison with manual off-line analysis and with an on-line industrial TOC analyser and an on-line titrimetric sensor (for the measurements of VFA, TA and PA) are provided to demonstrate the interest of spectral analysis in the mid infra-red domain for the monitoring of anaerobic digestion processes. In order to further illustrate the advantages of using such a technique, on-line measurements recorded during an accident of the pH regulation in the input (pH in the reactor went above 11 and biomass activity stopped) are shown. They demonstrate that, if carefully performed, the calibration can be extended outside its range while being still compatible with requirements of wastewater treatment processes.

Bacteria, Anaerobic↗
PubMed1998

Spatial features of angular drawing movements in Parkinson's disease patients.

The present study shows that drawings from Parkinson's disease (PD) patients display specific spatial features when compared to those produced by age-matched controls. Their drawings are globally smaller, or more precisely, the larger the requested size, the greater the size reduction. PD subjects have also more difficulties in producing obtuse than acute angles: angles of obtuse patterns are shrinking and their segment lengths are shortened. This could be due to the fact that an obtuse angle brings the effector joints close to the limits of their functional ranges of motion, which may be reduced in PD patients. Results related to segment direction show that PD patients are globally more imprecise than controls in the production of movement directions, but perform nevertheless relatively well for horizontals and verticals drawn in preferred directions. These results are referred to two contradictory models relating movement direction to the type of movement coordination involved.

Aged↗
PubMed1998

Nuclear magnetic resonance evidence of different muscular adaptations after resistance training.

OBJECTIVE: To evaluate muscle bioenergetics, muscle cross-sectional area (CSA), and soreness when the gastrocnemius was subjected to concentric and concentric/eccentric resistance training modes. DESIGN: Prospective study, before and after training. The subjects served as their own controls. SETTING: Rehabilitation center and nuclear magnetic resonance spectroscopy unit of a university hospital. PARTICIPANTS: Sixteen healthy young volunteers from the local physiotherapist school. INTERVENTION: Two distinct resistive training programs were evaluated on the gastrocnemius: a protocol consisting of concentric contractions only and a mixed concentric/eccentric program. MAIN OUTCOME MEASURES: Maximal isometric resistance was measured after each training session. Before and after training, muscle CSA was appreciated using magnetic resonance imaging, whereas changes in muscle pH, phosphorus metabolite ratios, maximal oxidative power (Pmax), and oxidative phosphorylation were studied using 31P nuclear magnetic resonance spectroscopy at rest and during an incremental exercise protocol. RESULTS: Magnetic resonance imaging revealed a significant increase (7.1%) in the gastrocnemius CSA in the concentric-eccentric group only. The PCr/Pi (8.3 +/- 0.9 vs 10.4 +/- 1.7) and PCr/ATP (3.68 +/- .36 vs 4.07 +/- .27) resting ratios increased significantly (p = .008) after concentric-eccentric resistance training. Pmax was significantly improved in the concentric-eccentric group (7.0 +/- 2.1W vs 8.4 +/- 1.8W: p < .02). This mixed protocol also reduced the incidence of muscular soreness. CONCLUSION: The data suggest that the improved oxidative mechanical power output could be due mainly to a greater muscle cross-section in the concentric-eccentric group, with circumstantial evidence suggesting a relatively higher type IIa fiber activity.

Adult↗
PubMed1997

Transformation of wheat with high molecular weight subunit genes results in improved functional properties.

The high molecular weight (HMW) subunits of wheat glutenin are major determinants of the elastic properties of gluten that allow the use of wheat doughs to make bread, pasta, and a range of other foods. There are both quantitative and qualitative effects of HMW subunits on the quality of the grain, the former being related to differences in the number of expressed HMW subunit genes. We have transformed bread wheat in order to increase the proportions of the HMW subunits and improve the functional properties of the flour. A range of transgene expression levels was obtained with some of the novel subunits present at considerably higher levels than the endogenous subunits. Analysis of T2 seeds expressing transgenes for one or two additional HMW subunits showed stepwise increases in dough elasticity, demonstrating the improvement of the functional properties of wheat by genetic engineering.

Glutens↗
PubMed1994

[Cortico-basal degeneration: a new entity].

Cortico-basal degeneration is a progressive disease comprisong characteristic features concerning both cortical and basal ganglionic dysfunction. Manifestations include akineto-rigid syndrome and apraxia strictly limited at disease onset to one hemibody, especially the left. Myoclonus, chorea a alien limb syndrome can begin within the clinicalcome. Functional exploration of the brain shows an asymmetric hypometabolism affecting both cortical and basal structures. Neuropathologic studies show pathological features including neuronal loss, gliosis and neuronal achromasia affecting the cortex (frontal and parietal), basal ganglia and locus niger. Further evaluation of this disease is needed to understand its links with the other neurological degenerative diseases especially progressive aphasia and Pick's disease.

Atrophy↗
PubMed1994

Homolateral ataxia and crural paresis: a crossed cerebral-cerebellar diaschisis.

A patient developed weakness of the right leg and homolateral ataxia of the arm, caused by a subcortical infarct in the area supplied by the anterior cerebral artery in the left paracentral region, demonstrated by CT and MRI. Cerebral blood flow studied by technetium-labelled hexamethyl-propylene-amine oxime using single photon emission computed tomography showed decreased blood flow in the left lateral frontal cortex and in the right cerebellar hemisphere ("crossed cerebral-cerebellar diaschisis"). The homolateral ataxia of the arm may be caused by decreased function of the right cerebellar hemisphere, because of a lesion of the corticopontine-cerebellar tracts, whereas crural hemiparesis is caused by a lesion of the upper part of the corona radiata.

Aged↗
PubMed1994

[Medical and technical compensation of disabilities].

Thanks to technological advances handicaps can be treated in a better way by physicians. This real Metrology of Handicap constitutes a preliminary stage to medical decision. Functional repercussions of a lesion can thus be accurately assessed before the well adapted compensatory means are conceived, prescribed and applied. A better understanding of physiopathological mechanisms involving lesion, deficit and handicap and of compensatory procedures used by disabled people depends from this assessment. Some examples will be reported such as energy expenditure, 3-dimensional biomechanical analysis of daily activities and the correlation between both approaches. Likewise, efficiency of therapeutics can be assessed such as the analysis of gait with appliances with different types of prosthetic feet or effects on muscle of various training programs. Besides, sophisticated orthesis, prosthesis and living aids can be developed with the help of data processing, robotics and electrostimulation. This new type of devices will be added to the range of standard devices developed at little cost by occupational therapists. As for the future, caution is imperative. "Repaired" man turning "robotised" is an image provided by media that might bring disillusions. On one hand, numerous social, economic and personal factors intervene in the determination of the plan for life by the individual and his family. Thereby, all the possibilities offered by technological advances might not be studied in the choice of plan of life. On the other hand, priorities in aims of an increasingly demanding individual economy will be dictated by collective economy focused on cost management. However, the concept of increase in life expectancy without disability will be relevant in the determination of health policy and the role of rehabilitation physicians will be all the more important because they are the only one to be able to coordinate a team qualified to choose and apply the best therapeutics. Times are over when below-knee amputees were directly referred to the orthoprosthetist after segmentation, At the present time, psychologists cannot decide alone on the re-orientation of patients with brain trauma and, Domoticians will never organize the life place of tetraplegic subjects.

Adolescent↗
PubMed1993

Plasma lipoproteins in cortical infarction versus transient ischaemic attacks: a case control study.

The authors investigated the relationship between plasma lipids and the risk for cortical infarction (61 cases) and transient ischaemic attacks (TIA) (35 cases) compared with matched controls. They observed a maximal increase of total cholesterol, of very low-density lipoprotein and low-density lipoprotein (LDL), triglycerides, total apolipoprotein (Apo), B,LDL-Apo B and Apo-A1, and small size high-density lipoprotein (HDL) and large size HDL whose separation was not possible. In contrast they observed a decrease of HDL-ApoE, a distribution of LDL in a single fraction and the presence of LDL of low weight in the group with cortical infarction with or without cardiac arrhythmias. For the first time, we describe a decrease of the HDL-ApoE/total ApoE ratio. TIA differed from the former group by a low level of HDL and the lack of abnormalities of Apo-A1, distribution of small and large size HDL, and in the distribution and the weight of LDL. These data suggest that previously demonstrated differences in LDL-cholesterol and HDL-cholesterol levels between patients with ischaemic stroke and control subjects may apply to patients with cortical infarction, and that in TIA there are changes in the distribution and the weight of LDL.

Aged↗
PubMed1993

So-called generalized epilepsy in children leading to frontal epilepsy with a frontal syndrome in adulthood: a clinical, EEG and radiological study of 10 cases.

The authors report 10 cases of epileptic patients with the onset in childhood of the clinical and EEG features of cryptogenic generalized epilepsy which evolved into frontal epilepsy, confirmed by the clinical and EEG features and was associated with a frontal syndrome. CT-scan and MRI showed mild atrophy in the frontal area, while SPECT showed a decrease in the frontal blood flow in 70% of the cases. The authors consider that frontal epilepsy may mimic generalized epilepsy.

Adolescent↗
PubMed1993

[Transient neurologic deficit preceding intracerebral hemorrhage. Physiopathological hypotheses].

Seventeen out of 238 cases (7%) of intracerebral hemorrhage were preceded by transient neurological deficit. In two cases, intracerebral hemorrhage and transient neurological deficit were thought to be due to amyloid angiopathy, this diagnosis was confirmed at autopsy in one case. In one case, intracerebral hemorrhage and transient neurological deficit were due to a cavernoma. In the other 14 cases, hypertension was the major risk factor. In 3 of them, CT-scans made after the transient neurological deficit but before the intracerebral hemorrhage showed deep small hypodensities suggestive of lacunas. The mechanisms of transient neurological deficit preceding intracerebral hemorrhage are reviewed.

Aged↗
PubMed1993

[Agenesis of the corpus callosum and epilepsy. 26 cases].

Agenesis of the corpus callosum is a cerebral malformation diagnosed by CT scan. Beside mental retardation, the most frequent clinical manifestation is epilepsy. In a personal study of 26 cases, the authors analysed the clinical features of epileptic seizures observed with this malformation. They put the stress on the paradoxical presence of generalized seizures.

Abnormalities, Multiple↗
PubMed1993

[Functional hemispheric arousal and egocentric reference. An experimental study in 20 normal subjects].

The aim of this study was to evaluate the influence of each hemispheric functional arousal (right or left) on the designation of a subjective egocentric reference. The subjective designation of a egocentric reference was measured and compared in 20 right-handers healthy volunteers in cognitive tasks concerning either the right or the left hemisphere. The location of the egocentric reference was different during right or left hemispheric arousal. The hemispheric arousal induce a displacement of the egocentric reference to the contralateral space. These results are compared with clinical and neurophysiological studies and suggest new explorations to the mechanisms of heminegligence.

Adult↗