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Biomedical subjects

J M Derlon

Publications and source records attributed to J M Derlon.

At least 19 recordsLinked to original sources
PubMed1992

Regional cerebral oxygen consumption, blood flow, and blood volume in healthy human aging.

Using high-resolution positron emission tomography and the oxygen 15 continuous inhalation method, we examined the changes in cerebral metabolic rate of oxygen, blood flow, blood volume, and oxygen extraction fraction as a function of age in 25 optimally healthy, unmedicated volunteers who ranged in age from 20 to 68 years. Subjects were strictly selected for absence of cerebrovascular risk factors, dementia, or mental disorders; they had neither biological nor clinical abnormalities, and no focal anomaly on computed tomographic scan. Regions of interest were determined according to the anatomical structures defined on corresponding computed tomographic scan cuts obtained using a stereotaxic head-positioning method. This same method was also used for positron emission tomographic imaging. There was no significant effect of aging on PaCO2 values, hematocrit, arterial blood pressure, cholesterol and triglyceride levels, and blood glucose levels. In most cerebral cortex gyri, the cerebral metabolic rate of oxygen significantly decreased with age according to a linear pattern, with the same magnitude (about -6% per decade) in all four lobes and on both sides. This effect of age on cortical cerebral metabolic rate of oxygen persisted when the possible influence of cortical atrophy, gender, and head size were partialled out. In contrast, the white matter, deep gray nuclei, thalamus, and cerebellum were not significantly affected. The cerebral blood volume declined with a similar pattern to cerebral metabolic rate of oxygen, while changes in cerebral blood flow were less significant, presumably because of larger variance of data across subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Phase II study of fotemustine in recurrent supratentorial malignant gliomas.

38 adults with recurrent supratentorial malignant gliomas, including glioblastoma multiforme (21), anaplastic astrocytomas (9), probably transformed low-grade astrocytomas (6), pinealoblastoma (1) and non-metastatic tumour of unknown histology (1), were treated with fotemustine 100 mg/m2 intravenously every week for 3 consecutive weeks followed by a 5-week rest period. Maintenance treatment consisted of one infusion every 3 weeks. Patients were divided into three groups according to treatment effect. 10 objective responses (26%) with a median time without progression of 32.7 weeks, 18 stabilisations (47%) and 10 failures (26%) were observed. Pathological findings of the initial primary tumour and neurological functional status were unequally distributed in these groups. Haematological and liver toxicities were mild, delayed, transient and reversible. Thrombocytopenia and leukopenia were more frequent (30%) in patients treated with prior chemotherapy. Fotemustine is a well tolerated active drug in recurrent malignant gliomas with an original and short treatment schedule.

Adolescent↗
PubMed1989

[11C]L-methionine uptake in gliomas.

Treatment of gliomas remains disappointing in spite of a great number of experimental biological data and of randomized therapeutic studies. This could be partly explained by the inefficiency of our conventional methods to assess the regional metabolism of these tumors. The use of positron emission tomography (PET) brings encouraging possibilities in this field. We report our preliminary experience of measuring regional cerebral methionine uptake with PET after intravenous injection of [11C]L-methionine. Twenty-two patients with histologically confirmed gliomas were studied. An ECAT II positron emission tomograph was used for scanning. The position of the plane was chosen to include a major section of the tumor in the reconstructed brain slice. The protocol required a two-step examination: 1) after injection of 15 to 25 mCi of [11C]L-methionine, 12 scans were performed over a period of 46 minutes; and 2) 18 hours later, regional cerebral blood volume was measured in the same slice after intravenous injection of 2 to 4 mCi of 68GaCl3. The tumoral region of interest was determined as being the area of maximum activity. For each patient we calculated the ratio, R, between the activity in this tumor region of interest and the activity in the contralateral healthy symmetric region of interest which was used as an "internal standard" for the same patient. We correlated the ratio R with the histological grading. In 22 patients, mean values of R were calculated for each tumor: Grade II (n = 5): R = 1.04 +/- 0.27; Grade III (n = 5): R = 1.68 +/- 0.22; and Grade IV (n = 12): R = 2.33 +/- 0.86.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

[Arteriovenous aneurysm of the corpus callosum with normal arteriography 9 years earlier].

Some arteriovenous malformations (A.V.M.s) visualized on a first angiography tend to enlarge gradually with time. Others A.V.M.s may decrease in size and even disappear. The authors report the case of a 18 year old woman admitted for a subarachnoid hemorrhage. A complete cerebral angiography was normal. Nine years later, an arteriovenous malformation of the corpus callosum was discovered. The reasons why angiography may fail to demonstrate an A.V.M., and the theories concerning the enlargement of A.V.M.S., are discussed.

Adolescent↗
PubMed1988

Local fibrinolytic therapy in ischemic carotid pathology.

Sixteen patients underwent local fibrinolytic therapy for thrombosis or embolism of the main trunk or intracranial branches of the internal carotid artery. There were eight cases of complete thrombosis of the internal carotid artery, five proximal stenoses of the internal carotid artery with extensive thrombus, one thrombus of the carotid siphon and two middle cerebral artery emboli. Indications for treatment included transient ischemic attacks in 11 cases, cerebral ischemia after carotid arteriography in two cases, and after surgery for atheromatous lesions of the carotid bifurcation in three cases. The fibrinolytic therapy was initiated during carotid surgery in three cases, where extended thrombosis of the internal carotid artery was discovered, which was inaccessible to a Fogarty catheter. The other 13 cases were treated during arteriography procedures. Lysis of the clot was always obtained. One patient died of hematoma of the frontal lobe. All other patients survived and showed neurologic improvement. The neurologic outcome was dependent on the duration and the degree of initial ischemia. Fibrinolytic therapy appears to be beneficial therapy for certain cases of cerebral ischemia.

Acute Disease↗
PubMed1988

Interhemispheric subdural haematomas: seven cases and review of the literature.

Interhemispheric subdural haematoma (ISH) is a rare complication of head injury with only 19 cases reported since 1940, but it may also occur spontaneously (three cases). In both circumstances, clotting disorders are frequent (six cases). We have recorded seven cases (five traumatic, two spontaneous). Classically ISH is due to tearing of bridging veins or cortical contusions. In one of our cases, it was due to arterial bleeding from a pericallosal branch. CT scan shows that ISH may extend above the tentorium and on the hemispheric convexity. Mortality is high (35%). The best operative procedure is parasagittal craniotomy. Chronic interhemispheric subdural haematomas also occur.

Adult↗
PubMed1987

[Hemodynamic study of obstructive lesions of the internal carotid artery: value of coupled measurement of regional cerebral blood flow and volume].

A study of 130 patients having presented either a transient ischemic attack or a completed stroke, or admitted for an asymptomatic carotid stenosis, allowed the following investigations: CT-scan, doppler, angiography, measurement of the regional cerebral blood flow (rCBF) by the study of 133Xe clearance (Novocerebrograph (R)), and measurement of the regional cerebral blood volume (rCBV) made by gamma emission tomography after autotransfusion of 99m Tc-labeled erythrocytes with an Elscint Apex 415 ECT (R) camera. Our aim was to look in which case a rCBF and/or a rCBV interhemispheric asymmetry was observed, by comparing the previous hemodynamic parameters with clinical, CT-scan and angiographic data. Although a rCBF and/or a rCBV asymmetry appeared more often among patients presenting with infarction than among those of the asymptomatic category, this does not seem specific for any clinical grade. The same statement applies to the comparison between hemodynamic parameters and CT data. The arterial lesions were classified in 4 groups: no stenosis (12 cases), uni or bilateral moderate carotid stenosis (40 cases), unilateral severe carotid stenosis or occlusion (65 cases), bilateral carotid severe stenosis or occlusion (13 cases). We observed a rCBF asymmetry among some patients in the 4 groups, although this was more frequent among the two latter groups. Nevertheless no case of a rCBV asymmetry was observed in the 2 first groups. Such an asymmetry was present in 31 percent of the patients belonging to the two latter groups. In patients of the third group the asymmetry was always due to a relative increase of rCBV beyond the carotid lesion.(ABSTRACT TRUNCATED AT 250 WORDS)

Arterial Occlusive Diseases↗
PubMed1986

Brain tumor protein synthesis and histological grades: a study by positron emission tomography (PET) with C11-L-Methionine.

Brain protein synthesis may be evaluated in vivo by a PET three compartment methionine model. 14 human brain tumor patients were studied. Protein synthesis rate (PSR) was increased in any glial tumor even in low grades, but this increase was statistically more important in anaplastic tumor. Radiotherapy action was evaluated in two patients. Local tumoral PSR was reduced to normal brain PSR after treatment. No difference was seen in normal cortex contralateral to the lesion between pre and post radiotherapy examination. 11 C-L-Methionine incorporation measured by PET looks as a very sensitive method for studying tumor metabolism and treatment effects.

Adult↗
PubMed1986

Hemodynamic study of internal carotid artery stenosis and occlusion: value of combined isotopic measurements of regional cerebral blood flow and blood volume.

The assessment of the intracranial hemodynamic consequences of obstructive lesions of the carotid artery by measuring resting rCBF is inadequate because cerebral blood flow may remain constant in spite of significant drops in the intraluminal pressure due to autoregulation. Moreover, flow may be permanently decreased following cerebral infarction, even if the arterial anatomical conditions have resumed their normal state because of the decreased metabolic demand of an infarcted area. Measurement of the regional cerebral blood volume (rCBV) helps with the hemodynamic assessment of these conditions, since there is a linear and inverse relationship between intraarterial pressure and intracranial blood volume. In 24 patients exhibiting various carotid and ischemic brain lesions we studied both rCBF and rCBV. The latter is a comparative measure between hemispheres obtained by single photon emission tomography after autotransfusion of 99m Technetium labeled erythrocytes. There was no correlation between rCBF and clinical status, CT scan or arterial lesions. There was no correlation between rCBV and clinical status or CT scan. There was, however, an interesting correlation between rCBV and the severity of the arterial lesion. The rCBV was symmetrical in all patients with normal or moderately stenotic carotid arteries before and after operation. In some patients with severe unilateral stenosis or occlusion, there was a significant relative increase of rCBV in the hemisphere downstream from the lesion, which disappeared after surgery (endarterectomy or extra-intracranial bypass). In some patients with severe and bilateral carotid lesions, we noted an asymmetry in rCBV that disappeared after a unilateral operation. Other patients with similar lesions develop asymmetry only after an operation that resulted in a relative increase in rCBV in the hemisphere supplied by the non-operated artery. In conclusion analysis of these results suggests that in this series of patients, rCBV modifications were the consequence of cerebral autoregulation distal to the arterial lesions and provided satisfactory assessment of hemodynamic improvement after surgical repair.

Adult↗
PubMed1986

[Percutaneous transluminal angioplasty in atheromatous stenosis of the proximal supra-aortic trunks: the brachiocephalic trunk and the subclavian artery].

The authors are reporting their experience about percutaneous transluminal angioplasty (PTA) in atheromatous stenosis of proximal supra-aortic arteries. In this series of 17 patients, with a 6-month follow-up, vertigos were the main clinical symptoms (8 cases), and it must be pointed out that 5 of these 8 patients also underwent a proximal angioplasty of one or the two of their vertebral arteries at the same time. Three subclavian steal-syndromes, one arterial insufficiency of an upper limb, one transient cerebral ischaemia, and four asymptomatic cases were also treated by the same procedure. For diagnosis as well as for follow-up, the authors are emphasizing the value of hemodynamic results of Doppler recording. As for the technics itself, it mainly derives from the PTA of the lower limbs arteries. The results in this series appear to be good from an hemodynamic point of view, with neither morbidity nor mortality.

Adult↗
PubMed1985

Transcutaneous angioplasty of vertebral artery atheromatous ostial stricture.

The authors report experience of intravascular angioplasty of atheromatous ostial strictures of the vertebral artery in 24 patients. After reviewing the technique, they outline the indications provided through Doppler velocimetric data. The results seem to be encouraging as symptoms disappeared completely in 21 patients.

Adult↗
PubMed1985

[Regional hemodynamic and metabolic consequences of temporo-sylvian anastomosis. Study of 15 patients by positron emission tomography].

Cerebral Blood Flow (CBF), Oxygen Extraction Fraction, and Oxygen utilization (CMRO2) have been studied in 15 patients before and After Extra-Intracranial Arterial bypass (EIAB), using PET and 150 steady-State Inhalation technique. Fourteen patients had carotid artery obstructive lesions and the last one a middle cerebral artery occlusion. In the whole group of patients, both CBF and CMRO2 increased significantly on both cerebral hemispheres after the EIAB. This effect was more marked in patients with extensive occlusive disease of neck vessels. This metabolic improvement afforded by EIAB in our patients suggests that long-standing hemodynamic failure may induce a metabolic depression that's still potentially reversible by surgical revascularization. On the other hand, improvement of focal CBF abnormalities depends, in our patients, upon the preoperative coupling of CBF-CMRO2 (mainly misery perfusion syndrome) as reported earlier.

Adult↗
PubMed1979

[Associated vertebral angioma and epidural cavernoma (author's transl)].

A 27 year old man developed a pyramidal syndrome with hypoesthesia up to the level of D8, over a period of two months. Radiographic examination revealed the presence of an angioma of D8. Selective angiography demonstrated that there was epidural invasion as well as an angioma of the vertebral body, and enabled embolization of the 2 pedicles of the lesion to be performed. This produced only a partial, temporary improvement, and a posterior epidural tumor was found and removed by operation. The histological appearance of the tumor was that of a cavernoma, and rapid and permanent recovery of normal neurological function was obtained after the operation. The authors discuss the pathogenicity of the neurological disorders associated with single bone angiomas, and the problems raised by their treatment.

Adult↗
PubMed1978

Angiography of the spinal cord after vertebral trauma.

Angiography of the spinal cord after trauma to the spine is reported in 14 new cases with neurological signs. Three types of angiographic signs are demonstrated: (1) arterial interruption of the anterior spinal artery, the ascending branch of the radiculomedullary arteries or the extravertebral arteries; (2) displacement of the anterior spinal artery without interruption; (3) hyperemia. The mechanism and significance of these signs are discussed.

Adolescent↗