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J L Dumas

Publications and source records attributed to J L Dumas.

At least 19 recordsLinked to original sources
PubMed2001

Study of the "sniffing position" by magnetic resonance imaging.

BACKGROUND: The "sniffing position" is widely considered essential to the performance of orotracheal intubation and has become the cornerstone of training in anesthesiology. However, the anatomic superiority of this patient head position has not been established. METHODS: Eight healthy young adult volunteers underwent magnetic resonance imaging scanning in three anatomic positions: head in neutral position, in simple extension, and in the "sniffing position" (neck flexed and head extended by means of a pillow). The following measurements were made on each scan: (1) the axis of the mouth (MA); (2) the pharyngeal axis (PA); (3) the laryngeal axis (LA); and (4) the line of vision. The various angles between these axes were defined: alpha angle between the MA and PA, beta angle between PA and LA, and delta angle between line of vision and LA. RESULTS: Both simple extension and sniffing positions significantly improved (P < 0.05) the delta angle associated with best laryngoscopic view. Our results show that the beta value increases significantly (P < 0.05) when the head position is shifted from the neutral position (beta = 7 +/- 6 degrees ) to the sniffing position (beta = 13 +/- 6 degrees ), and the alpha value slightly (but significantly) decreases (from 87 +/- 10 degrees to 63 +/- 11 degrees; P < 0.05). Anatomic alignment of the LA, PA, and MA axes is impossible to achieve in any of the three positions tested. There were no significant differences between angles observed in simple extension and sniffing positions. CONCLUSIONS: The sniffing position does not achieve alignment of the three important axes (MA, PA, and LA) in awake patients with normal airway anatomy.

Adult↗
PubMed2001

[Value of imaging in sarcoidosis].

Imaging plays an important role in identifying thoracic, abdominal and neurological localizations of sarcoidosis as well as ENT and bone localizations. It contributes to disease detection and is helpful for diagnostic, prognostic and therapeutic decision making and useful for therapeutic monitoring. The chest x-ray is particularly important in the initial work-up and to follow well-tolerated disease. Other investigations, depending on the localization, are helpful to follow the course of severe or chronic sarcoidosis.

Chronic Disease↗
PubMed2000

Central nervous system sarcoidosis: follow-up at MR imaging during steroid therapy.

PURPOSE: To document the changes observed at sequential magnetic resonance (MR) imaging of sarcoidosis lesions of the central nervous system (CNS) during treatment with corticosteroids. MATERIALS AND METHODS: The abnormalities detected in 24 patients (mean follow-up, 36 months) were compared before and after therapeutic periods (n = 75) that were divided into attack (high-dose), upkeep (decreased-dose), and minimal (low-dose) periods. Parenchymal lesions were classified as type 1 (enhanced with gadolinium), type 2 (demyelinating), or type 3 (lacunar) and were assessed as regressing, stable, or progressing. RESULTS: Seven of the 24 patients had several types of lesions. Isolated type 3 lesions (six patients) were the only lesions not associated with neurologic deficit. Type 1 lesions (13 patients) regressed in 22 of 22 attack periods and progressed in nine of 27 upkeep and minimal periods. MR imaging depicted relapses in patients with multifocal CNS involvement or long-standing CNS impairment or in those who had previously received steroid therapy. Type 2 (seven patients) and type 3 (13 patients) lesions remained stable in 68 of 68 therapeutic periods. Type 1 lesions appeared in three patients with type 2 and type 3 lesions during two upkeep and three minimal periods. Findings at follow-up MR imaging contributed to the reintroduction of high-dose corticosteroid therapy in eight patients. CONCLUSION: MR imaging can be used to differentiate between reversible and irreversible lesions in CNS sarcoidosis. MR imaging can be a useful tool for adjusting treatment to prevent irreversible CNS damage.

Adult↗
PubMed1999

Evaluation of trimethoprim and sulphamethoxazole as monotherapy or in combination in the management of toxoplasmosis in murine models.

The combination of trimethoprim (TMP) and sulphamethoxazole (SMX) is commonly used for the prevention of cerebral toxoplasmosis although there is no firm experimental basis to support this regimen. We used strain RH tachyzoites for challenge in the acute murine model of toxoplasmosis and found that TMP administered as a single agent, failed to eradicate toxoplasma even at the highest dose (70 mg/kg per day). SMX alone at 600 mg/kg per day, protected ten out of ten mice, although inoculation of brain from surviving animals to naive mice resulted in the development of an encephalitis. When combined, TMP (60 mg/kg per day) and SMX (300 mg/kg per day) protected ten out of ten mice and gave a 'cure' in four out of four mice. In the chronic cystogenic murine models, the combination TMP plus SMX administered from day 5 for 15 days or from day 28 for 288 days, gave protection and even apparent toxoplasmal eradication ('cure') at the highest dosing (60/300 mg/kg per day). However, microscopic severe encephalitis was found in mice classified as 'cured' after reinoculation. This result makes the interpretation of 'cure' very difficult. In conclusion TMP and SMX act synergistically, SMX being the more active arm of the combination. The combination was efficient in preventing the lethal development of chronic toxoplasma encephalitis, but did not guarantee complete recovery.

Animals↗
PubMed1999

Central nervous system involvement in Sjögren's syndrome: evidence from neuropsychological testing and HMPAO-SPECT.

OBJECTIVE: To investigate the clinical, neuropsychological and imaging manifestations of Sjögren's syndrome (SS), a chronic auto-immune disease with peripheral and central nervous system (CNS) involvement. DESIGN/METHODS: Fourteen female patients suffering from confirmed SS underwent within 2 weeks: neurological examination, immunological staging, brain MRI, brain 99m Tc-HMPAO SPECT, psychological evaluation and in-depth neuropsychological testing. RESULTS: All patients showed neuropsychological abnormalities. The cognitive symptoms were of the same type in all patients, mostly frontal lobe syndrome and memory problems. The neuropsychological involvement was not associated with other kinds of CNS involvement or MRI abnormalities, but accurately reflected HMPAO imaging results. CONCLUSIONS: The results of this study indicate that cognitive evaluation is the most sensitive clinical test to diagnose CNS involvement in patients with SS, and that CNS involvement in SS seems to be more frequent when systematically assessed by neuropsychological tests.

Adult↗
PubMed1998

[Sarcoidosis of the central nervous system].

PURPOSE: Current knowledge on central nervous system sarcoidosis. CURRENT KNOWLEDGE AND KEY POINTS: Sarcoidosis is localized in the central nervous system in 5 to 16% of the cases. Various neurological manifestations are observed, including: seizures, cognitive or psychic manifestations, hypothalamic and pituitary involvement, local pseudotumors, and hydrocephalus very frequently associated with asymptomatic lymphocytic meningitis and with cranial nerve palsy, particularly palsy of the seventh nerve, occurring less regularly. CNS localization is most often an early manifestation of the disease, unmasking sarcoidosis. It is often part of primary or secondary systemic polyvisceral sarcoidosis. The diagnosis is mainly based on two arguments: confirmation of the existence of systemic sarcoidosis and clinical and paraclinical compatibility of neurological abnormalities (particularly at magnetic resonance imaging [MRI]). Neurological histopathology is rarely necessary to confirm the diagnosis. Corticotherapy is indicated in all symptomatic cases and most often leads to a more or less complete clinical response evidenced by regression of active lesions identified on MRI. The treatment must often be prolonged for several years, and clinical and MRI evolution help guide therapeutical choices for dosages and threshold doses. CNS involvement is potentially severe with mortality and morbidity rates that are not insignificant. Limiting of iatrogenic risks requires adequate follow-up. PERSPECTIVES AND PROJECTS: Multicenter studies are necessary to determine factors influencing the incidence and long-term prognosis of CNS sarcoidosis treated with corticotherapy. The efficacy of treatments other than corticotherapy must be evaluated.

Adrenal Cortex Hormones↗
PubMed1997

Parenchymal neurocysticercosis: follow-up and staging by MRI.

We describe the evolution of parenchymal cerebral cysticerci on MRI, to assess signs of early cyst degeneration. We studied 15 lesions in four treated and one untreated patient. MRI was performed before therapy and repeated in the 1st month after each course of anticysticercus drugs, every 4 months during the 1st year and then annually; the follow-up period was 8-48 months. Lesions were classified according to changes in four features: cyst content and capsule signal, gadolinium enhancement and oedema signal. We were able to recognise each of the pathological phases; five MRI stages were identified. Stage 1 showed oedema and/or nodular gadolinium enhancement in the tissue invasion phase; stage 2 was cerebrospinal fluid-like signal within a cyst in the vesicular phase; stage 3 showed a thick capsule with an impure liquid content signal and surrounding oedema, in the cystic phase; stage 4 showed the disappearance of the cyst fluid content signal in the degenerative phase; stage 5 showed a calcified lesion in the residual phase. Stage 1 lesions disappeared after therapy; the other progressed from one stage to another. Stage 4 indicated the end of viability of the parasite and determined the point after which treatment was useless. On T2-weighted images changes in the cyst content differed according to the history of the lesion; nodular low intensity followed the natural degeneration of the parasite and a mixed fluid signal with punctate low signal seemed to represent the specific result of therapy. MRI staging can help in the evaluation of indications for treatment and facilitate clinical therapeutic trials.

Adolescent↗
PubMed1996

The abdominal linea alba: an anatomo-radiologic and biomechanical study.

Traditionally, the linea alba represents the principal route of approach in abdominal surgery and in consequence it is the commonest site of incisional hernia. The aim of this study was to review its morphology and to study its mechanical parameters of resistance, deformation and elasticity in order to compare these with the prosthetic materials most often used in the treatment of incisional hernia. Forty fresh cadavers were dissected and tests with a dynamometer and "bursting strength tester" were performed on samples taken from the linea alba at three levels: supra-umbilical, subumbilical and umbilical. Forty abdomino-pelvic scans were analysed. The morphologic results allowed definition of diastasis of the rectus mm. in terms of subject age: below 45 years of age diastasis was considered as a separation of the two rectus mm. exceeding 10 mm above the umbilicus, 27 mm at the umbilical ring and 9 mm below the umbilicus; above 45 years of age the corresponding values were 15 mm, 27 mm and 14 mm respectively. In the biomechanical study the subumbilical region exhibited a coefficient of elasticity greater than that of the supra-umbilical portion, but no significant difference in resistance was found between the different parts studied. The biomechanical results are compared with the corresponding data for prosthetic materials.

Abdominal Muscles↗
PubMed1996

Magnetic resonance angiographic analysis of atlanto-axial rotation: anatomic bases of compression of the vertebral arteries.

The aim of this study was to identify the functional anatomic factors involved in the maintenance or disturbance of flow in the vertebral aa. during atlanto-axial rotation. Fourteen healthy volunteers were studied by magnetic resonance angiography (MRA) by a three-dimensional sequence in phase contrast centered on the vertebral aa. at the level of the cranio-cervical junction before and after left rotation of the head. A decrease in the signal intensity of the arterial flow was sought for. The results were compared to the posterolateral development of the loop of the vertebral a. in its atlanto-axial segment in neutral position, and to the measurement of the angular opening between the atlas and axis in dynamic position. Seven subjects also had a three-dimensional CT study (3D CT) of the bony relations of C1 and C2 after rotation. In 4 subjects a disturbance of flow in the right vertebral a. was observed in the transverse foramen of C2. This occurred when two factors were combined: an under-developed atlanto-axial arterial loop and a C1-C2 angle exceeding 35 degrees in maximal rotation. In the other subjects a well-developed arterial loop and/or a C1-C2 angle of less than 35 degrees in maximal rotation were factors preserving the arterial flow. The risk factor associated with the C1-C2 angle seemed correlated in 3D CT with loss of the usual asymmetric character of rotation. A clinical application is reported with a case combining chronic rotational dysfunction of the cranio-cervical junction as shown by 3D CT and complete compression of the vertebral a. in MRA, confirmed by conventional angiography. A knowledge of this physiopathologic mechanism allows clinical detection and evaluation of the risk of any effect of pathology of the cranio-cervical junction on the vertebral a.

Adolescent↗
PubMed1996

[Postvaccination myelitis. Aspect and course followed by MRI].

We report the assessment by MRI of a case of radiculomyelitis after vaccination against tetanus-poliomyelitis. In the acute stage the appearance was an isolated myelitis of the conus medullaris with contrast enhancement. The upper thoracic cord presented central areas of high signal intensity on T2 weighted images. Rapid clinical recovery was correlated with resolution of abnormal enhancement. Follow-up MR at 5 months showed persistence of slight T2 prolongation in the conus medullaris and syringohydromyela of the thoracic cord. A single lesion of the spinal cord is a rare presentation of acute disseminated encephalomyelitis, the course of such lesions, to date not previously displayed by MR, is unknown. Proper diagnosis should help prevent administration of further vaccine doses.

Adult↗
PubMed1994

Three-dimensional CT analysis of atlantoaxial rotation: results in the normal subject.

A three-dimensional analysis of atlantoaxial rotation was made by computed tomography in ten healthy subjects. The method described allowed study of spatial relations between C1 and C2 interspace under both static and dynamic conditions, using a projection in a fixed transverse plane. The results demonstrated an axis of rotation for C2 slightly anterior to that for C1. Asymmetric rotation was observed, the separation between the transverse foramina of C1 and C2 being less marked on the side opposite to the direction of rotation of the head. This use of CT and these anatomic findings may be useful in the study of disorders of atlantoaxial rotation and their effect on the vertebral arteries.

Adult↗
PubMed1994

Radioanatomic study of the gastrocolic venous trunk.

The mode of formation, measurements and frequency of occurrence of the gastrocolic venous trunk were studied by the injection-corrosion technique in a series of 54 anatomic specimens and by the analysis of 50 CT studies in patients without hepatic or pancreatic disease. The gastrocolic trunk was found in 51 of the 54 anatomic specimens and in 27 of the 50 CT studies. The great variability in its formation, whether bipodal, tripodal or quadripodal, was noted. With a mean diameter of 4.9 mm, it opened into the anterior, right or antero-left aspects of the superior mesenteric v. at a mean distance of 15 mm below the inferior border of the spleno-mesenteric confluence. The value of preliminary CT assessment before an operation for portal hypertension or a pancreatic tumor or in the diagnosis of a splenic thrombosis is emphasised.

Aged↗
PubMed1994

Evaluation of the efficacy of prolonged administration of azithromycin in a murine model of chronic toxoplasmosis.

The efficacy of prolonged administration of azithromycin was evaluated in a murine model of lethal chronic toxoplasmosis. Mice were challenged intraperitoneally with cysts of a moderately virulent strain of Toxoplasma gondii, observed for 4 weeks and then allocated to the treatment or control group. All 26 animals given azithromycin 100 mg/kg/day for 100 days were protected compared with 19 of 25 control animals which died (P < 0.001). Nineteen of the 20 mice in the treatment group survived for an additional month while receiving the same azithromycin regimen but viable cysts were identified in the brain tissue of these animals when they were killed. Although there was no significant difference between the groups in terms of the number of cysts in the brain, the administration of azithromycin was associated with a reduction in brain inflammation. The concentrations of azithromycin in the brains of five animals ranged from 0.7 to 2.3 micrograms/g; there was no evidence of accumulation even after 100 doses. Azithromycin merits further evaluation as primary or secondary prophylaxis against toxoplasma encephalitis in individuals at risk of developing this complication.

Animals↗
PubMed1994

Pseudotumoral lymphocytic hypophysitis successfully treated by corticosteroid alone: first case report.

We report the first case of pseudotumoral lymphocytic hypophysitis successfully treated by corticosteroids without surgery. A 27-year-old woman had been monitored for chronic headache 13 months after giving birth, associated with amenorrhea and galactorrhea. Cranial magnetic resonance imaging revealed a markedly enlarged pituitary gland with a suprasellar extension; the only biochemical abnormality was a mild hyperprolactinemia. Because of a putative diagnosis of prolactinoma, bromocriptine was prescribed at a dose of 5 mg daily, soon followed by the transitory appearance of menstruation. Two years later, panhypopituitarism was present and was revealed by acute adrenal insufficiency. Magnetic resonance imaging revealed that the pituitary mass was the same as previously described, but hormonal investigation showed evidence of complete hypopituitarism and no hyperprolactinemia. Nuclear antibodies were negative as well as other autoantibodies. Human leukocyte antigen serological Class II typing was DR3/DR4. Lymphocytic hypophysitis was then suspected; in the absence of visual complication and because this patient refused surgery, corticosteroids were attempted at a daily dose of 60 mg of prednisone for 3 months, progressively decreased for the next 6 months. Under this treatment, a gradual recovery of all pituitary hormones was observed and magnetic resonance imaging showed a reduction of two-thirds in pituitary mass. Five months after the end of corticoid treatment, our patient relapsed with panhypopituitarism and an increase of pituitary volume. She underwent steroid treatment, and a biopsy was performed and confirmed the diagnosis of autoimmune hypophysitis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

[Imaging of pulmonary sarcoidosis].

Imaging plays a fundamental role in every step of the management of thoracic sarcoidosis. It contributes to the positive and differential diagnosis and assessment of the prognosis. It is able to distinguish between inflammatory lesions and fibrosis. It allows follow-up of the course of the disease with or without treatment and detection of any complications. Computed tomography provides very useful complementary information at each of these steps.

Humans↗