Search PubMed⌕ Search

Biomedical subjects

N Grenier

Publications and source records attributed to N Grenier.

At least 91 records · Page 5Linked to original sources
PubMed1990

Modifications of the sinusoidal barrier in a model of postsinusoidal hypertension in the rat. An ultrastructural study of endothelial cells.

Sinusoids and sinusoidal cells were examined by light and electron microscopy, using a rat model of postsinusoidal hypertension. One month after partial ligation of the vena cava (PLVC) above the hepatic veins, subcapsular hemorrhagic areas were visible with proliferation of hepatic veins; in non hemorrhagic areas, sinusoidal congestion was found. Postsinusoidal hypertension led to a significant increase in sinusoidal volume and to major abnormalities of the endothelium such as endothelial processes and pouches with numerous diaphragmed fenestrae; some red blood cells could be seen in these pouches. Endothelial cells sent out processes in between hepatocytes. Complete and incomplete pseudo-neolumens were found near sinusoids. Numerous Kupffer cells were located either in the sinusoidal barrier or infiltrating the Disse space close to extravasated red blood cells and perisinusoidal cell processes. 18 months after PLVC, lesions were much the same except for the presence of red blood cells in the Disse space.

Animals↗
PubMed1989

The neurocentral vertebral cartilage: anatomy, physiology and physiopathology.

The neurocentral cartilage (NCC) described by Schmorl was an intermediate cartilage has aroused discussion among numerous authors as to its role, its age of closure and its possible involvment in the genesis of scoliosis. The authors have attempted to define these problems on the basis of a histologic study of 20 vertebral specimens of different ages and a scanographic study of 25 children. The NCC remains open until adolescence and even beyond, but its maximal activity is probably around 5-6 years. Part of its function is to ensure growth of the posterior arch. Finally, the scanograms of scoliosis show the NCC to be more widely open on the concave side, as if this remained active for a longer period.

Adolescent↗
PubMed1989

Isthmic spondylolysis of the lumbar spine: MR imaging at 1.5 T.

The appearance on magnetic resonance (MR) images of the normal pars interarticularis in 13 patients was reviewed and contrasted with that of the pars in eight patients with spondylolysis. The pars defect usually had an intermediate signal intensity with all pulse sequences; however, this intensity was somewhat variable depending on the exact ratio of cartilage, fat, and fluid within each bone defect. The pars defect was best seen with spin-echo 600/20 (repetition time msec/echo time msec) images. In three cases, out-of-phase images showed the spondylolysis best, because of extension of fat to the borders of the defect. The sagittal view allowed one to separate spondylolysis from the joint space of posterior facets since the orientation of the defects is perpendicular to the facets; thus, a common pitfall encountered with cross-sectional axial imaging techniques is avoided. MR imaging poorly delineated bone fragments around the defect, which may produce nerve root impingement, but revealed other numerous complications that occur with spondylolysis, including spondylolisthesis and herniation of the disk above.

Adult↗
PubMed1989

Normal and disrupted lumbar longitudinal ligaments: correlative MR and anatomic study.

The posterior and anterior longitudinal ligaments of the lumbar spine appear on magnetic resonance (MR) images as thin lines of very low signal intensity in all spin-echo sequences. They cover the periphery of the outer fibers of the anulus fibrosus on sagittal images. The lumbar spine of 17 patients with 19 disk herniations was prospectively evaluated with MR imaging, and these findings were correlated with surgical findings. At surgery the posterior ligament was found to be disrupted in eight cases and intact in 11. Absence of a low-signal peripheral line around the herniated nucleus pulposus (HNP) was the most reliable sign of ligament rupture (no false-negative or false-positive findings). The peripheral line appeared to be interrupted in four cases, two of which were falsely positive. The two false-positive cases were related to a chemical shift artifact between epidural fat and the HNP. Presence of a normal and continuous peripheral line outlining the HNP excluded ligament disruption. The overall sensitivity for detecting disruption was 100%, and the specificity was 78%.

Adult↗
PubMed1989

[Oncocytic tumors of the kidney. 11 cases (1978-1987)].

Analysis of this series of cases reveals the following points: complementary investigations (computed tomography, magnetic resonance imaging) sometimes suggest the diagnosis, the oncocytic nature is often a surprise pathological finding, it is difficult to determine whether the lesion is a pure oncocytoma and the exact grade cannot be determined on frozen section, the choice between radical surgery and conservative surgery is made even more difficult, the study of the course of the disease raises the question of whether the term of oncocytoma should not be reserved to low grade tumours.

Adenoma↗
PubMed1989

[Angiography of hepatic angiomatosis in Rendu-Osler disease. Apropos of 3 cases].

The hepatic changes in hereditary hemorrhagic telangiectasia (Rendu Osler's disease) involve the extra- and intrahepatic vessels (enlarged hepatic artery, arteriovenous fistulas and inhomogeneous perfusion) and the hepatic parenchyma (fibrosis, telangiectasic cirrhosis). From three observations with liver involvement and imaged with angiography and dynamic CT, the authors emphasize on the role of the latter for detection of these changes, mostly arteriovenous fistulas.

Adult↗
PubMed1989

[Radiologic change of cartilage of the pelvis and the upper end of the femur during growth. Application to the surveillance of scolioses].

We retrospectively studied the radiographic documents of seventy girls with bony age varying from nine to eighteen years old and divided in nine equal groups and seventy boys with bony age from ten to nineteen years old. We analyzed the AP pelvic X ray of each child focusing on cartilages and ossification centers of both pelvic bone and upper femoral extremity. The purpose of this study was to assess the dates of apparition and ossification of these ossification centers and the dates of fusion of cartilages. The iliac ossification center (epiphysaris nucleus ilii) appears lately at bony age of thirteen years and half for girls and fourteen years and half for boys. The triradiate cartilage closes the earliest from its medial to its lateral portion before the apparition of the iliac ossification center. This closing date corresponds to the beginning of growth acceleration. Therefore, the period of growth acceleration can be identified by an accurate analyse of the triradiate cartilage closure on a single AP pelvic X ray.

Adolescent↗
PubMed1989

[Intrarenal kinetics of Gd-DOTA in sequential MRI in rabbits. Reproducibility study].

Ten normal rabbits and seven rabbits with experimental acute renal failure by tubular necrosis were studied with dynamic MR to evaluate the reproducibility of intrarenal kinetics of Gd-DOTA. Sequential spin-echo sequences with short TR (200 msec)/TE (26 msec) were used yielding a 29 sec acquisition time. A usual semi-quantitative analysis of intrarenal contrast demonstrated the reproducibility of some phases of the dynamic sequence in particular a drop in the signal within inner medulla between the third and the fourth minute after infusion. This effect, related to a high concentration of Gd-DOTA within the tubules was observed in 9 over 10 normal rabbits and in none of the rabbits with acute renal failure. The quantitative analysis calculation was based on relative signal intensity and contrast-to-noise ratio from the absolute signal intensity measure on regions-of-interest (ROI) on the cortex, outer medulla and inner medulla. No reproducibility of the variations with time of these parameters could be assessed. A great number of factors of variations or error, mainly during the measurements of signal intensity with ROI, could explain this lack of reproducibility. At the present, dynamic MR is therefore not able to quantitatively evaluate the renal function. Only a semi-quantitative estimation of tubular concentration can be deduced.

Acute Kidney Injury↗
PubMed1988

CT-diskography in the evaluation of the postoperative lumbar spine. Preliminary results.

Thirty-three patients with recurrent sciatica after lumbar-disk surgery were studied for recurrent herniated nucleus pulposus (HNP) by CT alone and CT-diskography (CTD). Twenty-six patients underwent surgical reexploration allowing correlation with CTD. CTD made a correct diagnosis of recurrent HNP in twenty-one patients showing an extravasation of the contrast medium from the disk space into the medullary canal. In two cases CTD was positive for recurrent HNP but surgery showed only fibrosis. The amount of contrast leak was very small in these two cases along the posterior common longitudinal ligament, and the junction with the disk was very narrow. Because of their clinical presentation three patients with negative studies were operated upon. One showed only fibrosis and the two others showed an associated disk fragment. Among the twenty-one true-positive cases, seven showed a combination of recurrent HNP and scarring. Contamination of CSF by the contrast medium through the dura was observed in two patients. Although a prospective comparative study between CTD and IV-contrast-enhanced CT is necessary, CTD appears to be a useful diagnostic procedure for recurrent HNP after surgery of the lumbar spine.

Adult↗
PubMed1988

[Diagnostic and therapeutic strategy in injuries of the kidney. Apropos of a series of 248 cases].

The analysis of a series of 248 cases led to the following conclusions: intravenous pyelography, together with nephrotomography and ultrasonography represent, the pillars of emergency assessment; computed tomography, performed systematically since 1985, is the most appropriate examination for the precise assessment of the lesions in a functioning kidney; arteriography is still essential in cases of urographically silent kidneys. The choice of therapeutic approach essentially depends on the type of the lesion: severe parenchymal lesions (type III) (58 cases) and certain cases of type II trauma (25 cases) underwent a deferred emergency operation which was as conservative as possible; pedicle lesions (type IV) and serious haemorrhagic lesions required emergency surgery (11 cases); type I or type II lesions with moderate hematomas were usually treated by simple observation (145 cases); cases of trauma seen at the stage of sequelae (8 cases) sometimes required a surgical solution (arteriovenous fistula, segmental ischaemia of the parenchyma with hypertension, encysted urinoma).

Adolescent↗
PubMed1988

[Cisplatin-based chemotherapy in the treatment of advanced-stage tumors of the bladder].

Since October 1984, 39 patients have been treated with cisplatin based chemotherapy for advanced bladder tumour of for pelvic recurrence or metastasis after total cystectomy. Cisplatin-methotrexate protocol (23 cases): 2 cases died during the first two cycles and 21 were evaluated after three cycles: only 39% of objective responses (2 CR-5 PR-2 MR) were observed with a mean survival not exceeding 12.6 months (7 deaths, 2 patients alive at the present time). All of the non-responders died within 4 to 16 months following the start of treatment (mean survival: 8.7 months). These particularly disappointing results led to the suspension of this protocol. Cisplatin-methotrexate-vinblastine protocol: 16 cases since September 1986. Eleven patients have been evaluated after three cycles: 3 CR-3 PR-5 PROG. The C.M.V. protocol appears to have a superior efficacy, principally on bladder, lymph node or lung lesions, at the cost of a higher but acceptable toxicity. Hepatic and central nervous system metastases were observed secondarily in this case.

Adult↗
PubMed1988

[Apparently isolated tumors of the adrenal gland. Apropos of 12 cases surgically treated].

12 patients with an adrenal tumour were observed in the absence of any known history of neoplasm at the stage of dissemination. In 9 cases the tumour was discovered accidentally. On the basis of the conclusions of the histological analysis following surgical exploration, the authors define the respective advantages of various examinations: laboratory assays, ultrasonography, CT scan, NMR and discuss the management of chance discovery of an adrenal mass.

Adenoma↗
PubMed1987

Degenerative lumbar disk disease: pitfalls and usefulness of MR imaging in detection of vacuum phenomenon.

Magnetic resonance (MR) images of the lumbar spine from 150 patients were retrospectively reviewed. In 14 of these patients, at 18 disk levels, a vacuum phenomenon (VP) had been identified on plain radiographs and/or computed tomographic scans. The MR imaging appearance of these gas collections in 17 disks was an area without signal, best seen on spin-echo sequences with short repetition time and echo time in the sagittal view. MR imaging precisely located the VP in the anulus fibrosus, the nucleus pulposus, and Schmorl nodes. In all but one case, degeneration of the disk was complete and associated with adjacent changes in vertebral bone. Pitfalls of MR imaging detection of VP included chemical shift artifact, calcifications, and tears without gas in the disk.

Gases↗
PubMed1987

Normal and degenerative posterior spinal structures: MR imaging.

A retrospective study of the magnetic resonance (MR) images of the lumbar spines of 13 healthy subjects and 30 patients with degenerative changes was done. In the healthy subjects, the vertebral facets, thickness of the cartilage and ligamentum flavum, signal characteristics of the bone marrow, and size of the spinal canal were studied. In the patients with degenerative changes in one of these structures, MR images in the sagittal plane were useful in demonstrating hypertrophy of the ligamentum flavum or the vertebral facets, in grading the degree of foraminal stenosis, and in measuring the sagittal diameter of the spinal cord. MR images in the axial plane facilitated detailed analysis of the facet joint and more accurate measurements of the thickness of the ligamentum flavum and spinal canal diameter. MR images were compared with computed tomography scans in 12 patients.

Adult↗
PubMed1987

[Left adrenal pseudomass. Apropos of a case of splenorenal anastomosis by the vein of the left pillar of the diaphragm].

A case of hepatocarcinoma on cirrhosis with portal hypertension is described. The anatomy of splenorenal anastomoses and their ultrasound and CT scan imaging characteristics are reviewed, and the interest of differential diagnosis from adrenal masses emphasized. Its importance is enhanced by the fact that the portal hypertension may be unrecognized as in the present case. Diagnostic effectiveness of ultrasound and CT scan imaging is discussed.

Adrenal Gland Neoplasms↗
PubMed1987

[The lesser omentum. Normal aspect and tumor pathology in ultrasonography and x-ray computed tomography].

The lesser omentum is a peritoneal partition that can be divided into two portions: superior or gastrohepatic ligament and inferior or duodenohepatic ligament, although differentiation is sometimes difficult. Ultrasound and CT scan imaging allowed perfect definition of vascular and glandular elements contained in the omentum, and normal morphology is described. Masses developing between the two leaves of which it is constituted usually project in front of adjacent vascular structures and/or prolonged into the liver hilum, and a fatty layer separates them from large prevertebral vessels. These different guidelines allow them to be distinguished from retroperitoneal celiomesenteric adenopathies. These expansive processes are almost always of glandular origin secondary to primary digestive, retroperitoneal, pelvic and even bronchial tumors. In contrast, primary tumors are rare in this region.

Humans↗