J. Certaines - Academia.edu (original) (raw)
Papers by J. Certaines
Aviation, space, and environmental medicine, 1981
Modifications in brain functions after exposure to a constant magnetic field have been noted in a... more Modifications in brain functions after exposure to a constant magnetic field have been noted in animals. For some authors, the main factor is the action of magnetic fields on tissular water. The relaxation times obtained by proton nuclear magnetic resonance should therefore be modified. Mice were placed in a 0.6 T constant magnetic field for 2 h. Their brain relaxation times (spin-lattice T1 and spin-spin T2), were measured 1-5 d after exposure and do not seem compatible with an initial and important modification of the water structure.
The aim of the PACS-IMACS project was to evaluate the results of the introduction of PACS (Pictur... more The aim of the PACS-IMACS project was to evaluate the results of the introduction of PACS (Picture Archiving and Communication System) in the hospital environment and to guide its evolution towards an IMACS concept (Image Management and Communication Systems).
Anticancer research
The erythroleukaemic K562 cell line and its adriamycin resistant counterpart were used to study r... more The erythroleukaemic K562 cell line and its adriamycin resistant counterpart were used to study resistance, its reversion and their consequences on the levels and localisation of lipids detected in proton nuclear magnetic resonance (NMR) spectra. On whole cells, the mobile lipids giving rise to a NMR signal were significantly decreased in the resistant cells when compared to the sensitive ones; these lipids recovered partially in the reverting cells. According to the spinlattice relaxation times (T1), the lipids detected appeared to be in a similar environment in sensitive and reverting cells. In membrane-enriched fractions, mobile lipid levels were not significantly different in the sensitive and reverting cell lines but decreased in resistant ones. Moreover, lipid droplets stained with a fluorescent Nile red lipophilic probe showed the presence of highly fluorescent particles in the samples in which NMR detected high levels of mobile lipids. These results suggest the participation...
Journal of Magnetic Resonance Imaging, 2000
Quantitative measurement of mechanical properties of biologic tissues may have several applicatio... more Quantitative measurement of mechanical properties of biologic tissues may have several applications for diagnosis or biomechanic modeling in sports medicine, traumatology, or computer-guided surgery. The magnetic resonance imaging (MRI) methods previously tested for these applications all required synchronization between MRI acquisition pulses and the mechanical stimulation. A new unsynchronized method operating with no prior knowledge of intensity, direction, and frequency of the mechanical waves is proposed. A specifically modified SPAMM (SPAtial Modulation of Magnetization) sequence has been used, operating on a 0.2-T MRI system. The experimental results obtained on test objects fit well with theoretical calculations. The new proposed method is very fast (a less than 5-second acquisition time) for routine clinical use.
Bulletin de la Société médicale d'Afrique noire de langue française, 1974
Brain Oncology Biology, diagnosis and therapy, 1987
Stereotactic examinations with CT scan have previously demonstrated their performances but the sp... more Stereotactic examinations with CT scan have previously demonstrated their performances but the specific interest of MRI in the neurooncology field requires the transposition of a well established CT scan method into NMR technology (2,3,6). Main problems concern the material included in the stereotactic frame (without any ferromagnetic substances), the position of the patient in the imaging system and the visibility of constrast substances in MRI. Regarding these three demands, we have developed a convenient stereotactic frame for both MRI and CT scans. This frame is of very simple use according to the atraumatic fixation on the patient head and allows short time examination compatible with routine use of imaging.
Magnetic Resonance Imaging, 1984
Proton nuclear magnetic resonance (NMR) was used in a study of 40 patients with thyroid tumors fo... more Proton nuclear magnetic resonance (NMR) was used in a study of 40 patients with thyroid tumors following partial or total thyroidectomy. Three patient groups were considered: those with nodules showing increased uptake, those with solitary nodules with decreased uptake, and those with multinodular goiters. Spin-lattice and spin-spin relaxation times (T1 and T2) were measured on samples of nodular and extranodular tissue from each patient. Increased T1 and T2 were observed for benign cold nodules, an increase in T1 alone for nodules with increased uptake, and a wide fluctuation in T1 and T2 for multinodular goiters. The four cancers in the series did not show a distinctive proton NMR pattern in comparison with the other nodular structures studied. The results point to the feasibility of applying NMR techniques to the detection of thyroid disease.
Annales d'endocrinologie, 1986
To date, T1 and T2 proton relaxation times in Nuclear Magnetic Resonance have not been widely stu... more To date, T1 and T2 proton relaxation times in Nuclear Magnetic Resonance have not been widely studied in thyroid disorders. In an earlier study, we compared 99mTc and histological data with T1 and T2 relaxation times. We found that nodules heterogeneity affect NMR results. This should therefore be taken into account when interpreting magnetic resonance images. The purpose of the present study was to compare T1 and T2 in thyroid tissues according to the diagnosis and the different histological components which had been quantitative defined by histomorphometric methods. 71 samples from 43 patients were examines: 35 euthyroid multiheteronodular goitres, 5 hot nodules, 2 papillary carcinomas, 1 Basedow's disease. The results show that image interpretation according to histology is difficult.
Cancer detection and prevention, 1981
Increased spin-lattice T1 and spin-spin T2 proton relaxation times of malignant tissues are by no... more Increased spin-lattice T1 and spin-spin T2 proton relaxation times of malignant tissues are by now well documented phenomena. A "systemic effect" of cancer, evidenced by NMR, has been demonstrated in different experimental models. The present study was undertaken to examine systemic effect in man by measuring serum relaxation times and related biochemical variables in 224 healthy control individuals and 311 patients with solid tumors at different stages of growth. The increase in T1 values is statistically significant in the advanced cancer group but not in the nonevolutive disease group, compared to healthy control group. Variations of T2 values are not significant in this study. There is no correlation of T1 increase with serum ions, total proteins or protein fractions.
Comptes rendus de l'Académie des sciences. Série III, Sciences de la vie, 1988
Proton magnetic resonance spectroscopy of plasma indicates an alteration of proteolipid methyl an... more Proton magnetic resonance spectroscopy of plasma indicates an alteration of proteolipid methyl and methylene resonances after heart transplantation. The intensity of these alterations is modulated by the transplant tolerance phenomena and allows the accurate detection of heart graft rejection. These results reinforce the analogy between the immunology of graft tolerance and the immunology of cancer or pregnancy where identical alterations have been identified.
Journal de Radiologie, 2005
Spectroscopy Letters, 1997
ABSTRACT A new tissue-equivalent substance for the MR dosimetry has been developed. It is compose... more ABSTRACT A new tissue-equivalent substance for the MR dosimetry has been developed. It is composed of water, bovine serum albumin, acrylamide with N,N′-methylene-bis-acrylamide, ammonium ferrous sulphate and sulphuric acid. The elemental composition, mass density, and electron density of the PIRA gel are closer to real tissue than those of dosimeter gels previously investigated. Irradiation causes the changes in the NMR properties of the gel. The dose dependence of NMR longitudinal relaxation rate, R1, is reproducible (less than 2% variation) and is linear up to about 30 Gy, with a slope of 0.023 sGy at 0.48 T. The gel, referred to as PIRA, can be used to obtain accurate radiation dose distribution with conventional magnetic resonance imaging devices.
Spectroscopy Letters, 2001
ABSTRACT The radiation-response of the Fricke-doped protein-polymer gel (PIRA) was studied by H N... more ABSTRACT The radiation-response of the Fricke-doped protein-polymer gel (PIRA) was studied by H NMR, as well as with spectrophotometric and fluorescence methods. In this gel, the ionizing radiation induces an increase in the NMR longitudinal relaxation rate, R1, of protons. It was observed that: I) the main mechanism responsible for the increase in R1 was the oxidation of ferrous to ferric ions; ii) the total amount of acrylamide with the same weight fraction (50%C) of the crosslinker N,N′-methylene-bis-acrylamide in the range 6%–12% by weight had no effect upon the R1 dose sensitivity; iii) the increase in the bovine serum albumin (BSA) concentration caused a drop in the R1 dose response sensitivity; iv) the R1 dose sensitivity was pH dependent. The four-site fast exchange model for R1 dose response was applied to calculate the ferric ions chemical yield G(Fe). The G(Fe) value obtained from the NMR data agreed with that determined independently from spectrophotometric measurements.
European Neurology, 1995
Stroke is the most common life-threatening neurological disease and the third most frequent cause... more Stroke is the most common life-threatening neurological disease and the third most frequent cause of death after heart disease and cancer [1]. Two major categories of stroke exist:(1) ischemic, in which inadequate blood flow to the brain causes an area of cerebral damage, ...
Dementia and Geriatric Cognitive Disorders, 1993
The stunning accumulation of data on the physiopathology of Alzheimer's disease i... more The stunning accumulation of data on the physiopathology of Alzheimer's disease is a real hinderance to pharmacologists who have to make decisions as to what molecules should be assessed first in man. Considering the cumbersomeness and cost of clinical trials in that field, a review of potential targets for drugs that are supposed to be active against the disease has become necessary, for a true definition of the rational justifications of trials to be envisaged.
Archives Of Physiology And Biochemistry, 1989
Metabolic impairment in skeletal muscle was suggested to be involved in the development of local ... more Metabolic impairment in skeletal muscle was suggested to be involved in the development of local mechanical fatigue but until now results have dealt with short activity periods whereas little data on exhaustive and prolonged exercises are available. Stimulations of rat leg muscle lasting 45 min were induced by tetanic trains delivered via sciatic nerve at five different rhythms. Energy metabolism of the stimulated gastrocnemius muscle was followed by 31P NMR spectroscopy using surface coil while mechanical function was recorded. Our data showed a decrease in the force level to very low values a few minutes after exercise onset. This mechanical impairment only induced a transient metabolic failure followed by rapid restoration of high phosphocreatine (PCr) values and intracellular pH, without mechanical recovery. In addition, at the end of exercise, the PCr content was proportional to the fatigue level. As these experiments could not have impaired neuromuscular junction, the data would indicate that fatigue was maintained by a mechanism which does not appear to depend directly on muscle cell energy stores.
Molecular and cellular biochemistry, 1999
Mitochondrial creatine kinase (Mi-CK) function in viable mitochondria from developing rat skeleta... more Mitochondrial creatine kinase (Mi-CK) function in viable mitochondria from developing rat skeletal muscle was assessed both by polarographic measurements of creatine-induced respiration and 31P NMR spectroscopy measurements of phosphocreatine (PCr) synthesis. Creatine-induced respiration was observed in very young rats and increased by 50% to 35 days of age. PCr synthesis was present in 7 day old animals and increased by 300% reaching levels measured in 35 day and adult muscle. Unlike reports showing Mi-CK enzymatic activities but no mitochondrial function in several situations, a concomitant progression of enzymatic activity and mitochondrial function was evidenced during the developmental stages of skeletal muscle Mi-CK in altricious animals. These results correlated with the progressive pattern of muscle differentiation during development of motricity in such animals. The observation that Mi-CK is functional in skeletal muscle mitochondria very early after birth, strongly favors ...
Annales de biologie clinique, 1982
Médecine et Maladies Infectieuses, 1982
ABSTRACT
Aviation, space, and environmental medicine, 1981
Modifications in brain functions after exposure to a constant magnetic field have been noted in a... more Modifications in brain functions after exposure to a constant magnetic field have been noted in animals. For some authors, the main factor is the action of magnetic fields on tissular water. The relaxation times obtained by proton nuclear magnetic resonance should therefore be modified. Mice were placed in a 0.6 T constant magnetic field for 2 h. Their brain relaxation times (spin-lattice T1 and spin-spin T2), were measured 1-5 d after exposure and do not seem compatible with an initial and important modification of the water structure.
The aim of the PACS-IMACS project was to evaluate the results of the introduction of PACS (Pictur... more The aim of the PACS-IMACS project was to evaluate the results of the introduction of PACS (Picture Archiving and Communication System) in the hospital environment and to guide its evolution towards an IMACS concept (Image Management and Communication Systems).
Anticancer research
The erythroleukaemic K562 cell line and its adriamycin resistant counterpart were used to study r... more The erythroleukaemic K562 cell line and its adriamycin resistant counterpart were used to study resistance, its reversion and their consequences on the levels and localisation of lipids detected in proton nuclear magnetic resonance (NMR) spectra. On whole cells, the mobile lipids giving rise to a NMR signal were significantly decreased in the resistant cells when compared to the sensitive ones; these lipids recovered partially in the reverting cells. According to the spinlattice relaxation times (T1), the lipids detected appeared to be in a similar environment in sensitive and reverting cells. In membrane-enriched fractions, mobile lipid levels were not significantly different in the sensitive and reverting cell lines but decreased in resistant ones. Moreover, lipid droplets stained with a fluorescent Nile red lipophilic probe showed the presence of highly fluorescent particles in the samples in which NMR detected high levels of mobile lipids. These results suggest the participation...
Journal of Magnetic Resonance Imaging, 2000
Quantitative measurement of mechanical properties of biologic tissues may have several applicatio... more Quantitative measurement of mechanical properties of biologic tissues may have several applications for diagnosis or biomechanic modeling in sports medicine, traumatology, or computer-guided surgery. The magnetic resonance imaging (MRI) methods previously tested for these applications all required synchronization between MRI acquisition pulses and the mechanical stimulation. A new unsynchronized method operating with no prior knowledge of intensity, direction, and frequency of the mechanical waves is proposed. A specifically modified SPAMM (SPAtial Modulation of Magnetization) sequence has been used, operating on a 0.2-T MRI system. The experimental results obtained on test objects fit well with theoretical calculations. The new proposed method is very fast (a less than 5-second acquisition time) for routine clinical use.
Bulletin de la Société médicale d'Afrique noire de langue française, 1974
Brain Oncology Biology, diagnosis and therapy, 1987
Stereotactic examinations with CT scan have previously demonstrated their performances but the sp... more Stereotactic examinations with CT scan have previously demonstrated their performances but the specific interest of MRI in the neurooncology field requires the transposition of a well established CT scan method into NMR technology (2,3,6). Main problems concern the material included in the stereotactic frame (without any ferromagnetic substances), the position of the patient in the imaging system and the visibility of constrast substances in MRI. Regarding these three demands, we have developed a convenient stereotactic frame for both MRI and CT scans. This frame is of very simple use according to the atraumatic fixation on the patient head and allows short time examination compatible with routine use of imaging.
Magnetic Resonance Imaging, 1984
Proton nuclear magnetic resonance (NMR) was used in a study of 40 patients with thyroid tumors fo... more Proton nuclear magnetic resonance (NMR) was used in a study of 40 patients with thyroid tumors following partial or total thyroidectomy. Three patient groups were considered: those with nodules showing increased uptake, those with solitary nodules with decreased uptake, and those with multinodular goiters. Spin-lattice and spin-spin relaxation times (T1 and T2) were measured on samples of nodular and extranodular tissue from each patient. Increased T1 and T2 were observed for benign cold nodules, an increase in T1 alone for nodules with increased uptake, and a wide fluctuation in T1 and T2 for multinodular goiters. The four cancers in the series did not show a distinctive proton NMR pattern in comparison with the other nodular structures studied. The results point to the feasibility of applying NMR techniques to the detection of thyroid disease.
Annales d'endocrinologie, 1986
To date, T1 and T2 proton relaxation times in Nuclear Magnetic Resonance have not been widely stu... more To date, T1 and T2 proton relaxation times in Nuclear Magnetic Resonance have not been widely studied in thyroid disorders. In an earlier study, we compared 99mTc and histological data with T1 and T2 relaxation times. We found that nodules heterogeneity affect NMR results. This should therefore be taken into account when interpreting magnetic resonance images. The purpose of the present study was to compare T1 and T2 in thyroid tissues according to the diagnosis and the different histological components which had been quantitative defined by histomorphometric methods. 71 samples from 43 patients were examines: 35 euthyroid multiheteronodular goitres, 5 hot nodules, 2 papillary carcinomas, 1 Basedow's disease. The results show that image interpretation according to histology is difficult.
Cancer detection and prevention, 1981
Increased spin-lattice T1 and spin-spin T2 proton relaxation times of malignant tissues are by no... more Increased spin-lattice T1 and spin-spin T2 proton relaxation times of malignant tissues are by now well documented phenomena. A "systemic effect" of cancer, evidenced by NMR, has been demonstrated in different experimental models. The present study was undertaken to examine systemic effect in man by measuring serum relaxation times and related biochemical variables in 224 healthy control individuals and 311 patients with solid tumors at different stages of growth. The increase in T1 values is statistically significant in the advanced cancer group but not in the nonevolutive disease group, compared to healthy control group. Variations of T2 values are not significant in this study. There is no correlation of T1 increase with serum ions, total proteins or protein fractions.
Comptes rendus de l'Académie des sciences. Série III, Sciences de la vie, 1988
Proton magnetic resonance spectroscopy of plasma indicates an alteration of proteolipid methyl an... more Proton magnetic resonance spectroscopy of plasma indicates an alteration of proteolipid methyl and methylene resonances after heart transplantation. The intensity of these alterations is modulated by the transplant tolerance phenomena and allows the accurate detection of heart graft rejection. These results reinforce the analogy between the immunology of graft tolerance and the immunology of cancer or pregnancy where identical alterations have been identified.
Journal de Radiologie, 2005
Spectroscopy Letters, 1997
ABSTRACT A new tissue-equivalent substance for the MR dosimetry has been developed. It is compose... more ABSTRACT A new tissue-equivalent substance for the MR dosimetry has been developed. It is composed of water, bovine serum albumin, acrylamide with N,N′-methylene-bis-acrylamide, ammonium ferrous sulphate and sulphuric acid. The elemental composition, mass density, and electron density of the PIRA gel are closer to real tissue than those of dosimeter gels previously investigated. Irradiation causes the changes in the NMR properties of the gel. The dose dependence of NMR longitudinal relaxation rate, R1, is reproducible (less than 2% variation) and is linear up to about 30 Gy, with a slope of 0.023 sGy at 0.48 T. The gel, referred to as PIRA, can be used to obtain accurate radiation dose distribution with conventional magnetic resonance imaging devices.
Spectroscopy Letters, 2001
ABSTRACT The radiation-response of the Fricke-doped protein-polymer gel (PIRA) was studied by H N... more ABSTRACT The radiation-response of the Fricke-doped protein-polymer gel (PIRA) was studied by H NMR, as well as with spectrophotometric and fluorescence methods. In this gel, the ionizing radiation induces an increase in the NMR longitudinal relaxation rate, R1, of protons. It was observed that: I) the main mechanism responsible for the increase in R1 was the oxidation of ferrous to ferric ions; ii) the total amount of acrylamide with the same weight fraction (50%C) of the crosslinker N,N′-methylene-bis-acrylamide in the range 6%–12% by weight had no effect upon the R1 dose sensitivity; iii) the increase in the bovine serum albumin (BSA) concentration caused a drop in the R1 dose response sensitivity; iv) the R1 dose sensitivity was pH dependent. The four-site fast exchange model for R1 dose response was applied to calculate the ferric ions chemical yield G(Fe). The G(Fe) value obtained from the NMR data agreed with that determined independently from spectrophotometric measurements.
European Neurology, 1995
Stroke is the most common life-threatening neurological disease and the third most frequent cause... more Stroke is the most common life-threatening neurological disease and the third most frequent cause of death after heart disease and cancer [1]. Two major categories of stroke exist:(1) ischemic, in which inadequate blood flow to the brain causes an area of cerebral damage, ...
Dementia and Geriatric Cognitive Disorders, 1993
The stunning accumulation of data on the physiopathology of Alzheimer's disease i... more The stunning accumulation of data on the physiopathology of Alzheimer's disease is a real hinderance to pharmacologists who have to make decisions as to what molecules should be assessed first in man. Considering the cumbersomeness and cost of clinical trials in that field, a review of potential targets for drugs that are supposed to be active against the disease has become necessary, for a true definition of the rational justifications of trials to be envisaged.
Archives Of Physiology And Biochemistry, 1989
Metabolic impairment in skeletal muscle was suggested to be involved in the development of local ... more Metabolic impairment in skeletal muscle was suggested to be involved in the development of local mechanical fatigue but until now results have dealt with short activity periods whereas little data on exhaustive and prolonged exercises are available. Stimulations of rat leg muscle lasting 45 min were induced by tetanic trains delivered via sciatic nerve at five different rhythms. Energy metabolism of the stimulated gastrocnemius muscle was followed by 31P NMR spectroscopy using surface coil while mechanical function was recorded. Our data showed a decrease in the force level to very low values a few minutes after exercise onset. This mechanical impairment only induced a transient metabolic failure followed by rapid restoration of high phosphocreatine (PCr) values and intracellular pH, without mechanical recovery. In addition, at the end of exercise, the PCr content was proportional to the fatigue level. As these experiments could not have impaired neuromuscular junction, the data would indicate that fatigue was maintained by a mechanism which does not appear to depend directly on muscle cell energy stores.
Molecular and cellular biochemistry, 1999
Mitochondrial creatine kinase (Mi-CK) function in viable mitochondria from developing rat skeleta... more Mitochondrial creatine kinase (Mi-CK) function in viable mitochondria from developing rat skeletal muscle was assessed both by polarographic measurements of creatine-induced respiration and 31P NMR spectroscopy measurements of phosphocreatine (PCr) synthesis. Creatine-induced respiration was observed in very young rats and increased by 50% to 35 days of age. PCr synthesis was present in 7 day old animals and increased by 300% reaching levels measured in 35 day and adult muscle. Unlike reports showing Mi-CK enzymatic activities but no mitochondrial function in several situations, a concomitant progression of enzymatic activity and mitochondrial function was evidenced during the developmental stages of skeletal muscle Mi-CK in altricious animals. These results correlated with the progressive pattern of muscle differentiation during development of motricity in such animals. The observation that Mi-CK is functional in skeletal muscle mitochondria very early after birth, strongly favors ...
Annales de biologie clinique, 1982
Médecine et Maladies Infectieuses, 1982
ABSTRACT