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Biomedical subjects

G Marchal

Publications and source records attributed to G Marchal.

At least 271 records · Page 15Linked to original sources
PubMed1990

Metastatic calcification within bone. The main cause of osteosclerosis in hypervitaminosis D3. Radiologic-pathologic correlation.

Because the pathogenesis of osteosclerosis in hypervitaminosis D is still not well elucidated, the authors experimentally studied hypervitaminosis D3 in 66 rabbits by injecting different doses of vitamin D3. Contact radiographs of bone specimens showed various signs of osteosclerosis, including dense epiphyses and metaphyses, thickened bony articular surfaces, dense metaphyseal bands, modeling defects at the metaphysis, and dense and thickened cortical bone. The corresponding pathologic sections showed that conspicuous metastatic calcification coated the trabeculae and filled bone marrow cavity and caverns in the original but porotic cortical and periosteal new bone. Rather than being resorbed, the metastatic calcifications were embedded in a thick layer of newly formed bone 6 to 14 weeks after vitamin D3 withdrawal. This study suggests that in hypervitaminosis D3, the osteoblasts and bone marrow undergo degeneration, leading to necrosis and calcification. After vitamin D3 withdrawal, osteoblasts reappear and become overactive, leading to overossification.

Animals↗
PubMed1990

Percutaneous transhepatic cholecystostomy for acute complicated cholecystitis in elderly patients.

We report our experience with percutaneous transhepatic cholecystostomy in 10 elderly patients with acute cholecystitis, complicated by empyema formation. Most of these patients has severe underlying disease, rendering them at high risk for surgical intervention. In all patients, the percutaneous procedure was followed by a rapid regression of clinical symptoms and of radiologic abnormalities. Six were considered inoperable. Three of these remain free of biliary symptoms, respectively 22, 10, and 7 months after percutaneous cholecystostomy. Three others died of nonbiliary disease 1-4 months after cholecystostomy. Three patients underwent successful elective cholecystostomy 1-5 wk after percutaneous cholecystostomy. In one patient, cholecystectomy had to be performed because of recurrence of hydrops, 1 wk after catheter removal. In our opinion, percutaneous transhepatic cholecystostomy is a safe and effective procedure in the treatment of elderly patients with acute complicated cholecystitis. It can be followed by elective cholecystectomy in good surgical candidates, or by an expectant conservative management in high surgical risk patients.

Acute Disease↗
PubMed1990

MRI of intraparenchymal hematoma: responsible mechanisms.

The MRI appearance and evolution of hemorrhage remains a difficult entity. A typical example of the MR visualization of an intracerebral bleeding in the basal ganglia and the internal capsule at 1.5 T is presented. The sequential biochemical and physical changes in an hemorrhage are described.

Adult↗
PubMed1990

Duplex Doppler evaluation of renal allograft dysfunction: Doppler signal quantitation and pathologic correlation.

The value of quantitative duplex Doppler sonography in discriminating the different possible causes of renal transplant dysfunction was prospectively studied in 60 patients during 65 episodes of renal function impairment. Final diagnosis at histology was acute rejection (n: 30), acute tubular necrosis (n: 4), cyclosporin nephrotoxicity (n: 16) and chronic rejection (n: 15). Duplex sonography was done the day a percutaneous biopsy was taken and before any therapy was started. Arterial Doppler signals obtained from the segmental, interlobar and arcuate arteries were both morphologically and quantitatively analysed. For quantitative analysis we used the resistive index as proposed by Pourcelot on the one hand, and introduced a variant resistive index on the other hand. Morphological analysis yielded no discriminative value. Comparing both quantitative methods--the resistive index of Pourcelot and the variant resistive index--clearly higher specificities--71% using the variant resistive index, 28% using the resistive index of Pourcelot--for excluding acute rejection from the other possible causes of renal function impairment could be achieved. A nephrectomy was done on 7 patients with severe transplant dysfunction. Microangiographies performed on these nephrectomy specimens were correlated with previous Doppler studies and with histology.

Graft Rejection↗
PubMed1990

Magnetic resonance imaging in central pontine myelinolysis.

The MRI findings at 1.5 Tesla of central pontine myelinolysis in 2 alcoholic patients are reported. The lesion was confined to the pons in both cases, with strong hyperintensity on T2-weighted and hypointensity on T1-weighted images. In both cases MRI revealed typical symmetrical sparing of the ventrolateral tracts in the pons.

Adult↗
PubMed1990

[High-field magnetic resonance imaging of the liver compared to x-ray computed tomography. Preliminary study apropos of 39 cases].

Thirty nine patients with one or more focal hepatic lesions were examined by contrast enhanced computed tomography (CE-CT) and magnetic resonance imaging (MRI). A variety of pulse sequences--spin echo (SE), gradient echo (GE) and inversion recovery (IR)--have been reported in the literature on MRI concerning the detection and characterization of liver tumors. Multiple studies have compared MRI at different field strengths to CT. As controversy still exists concerning the optimal pulse sequence on MRI, CE-CT has been compared to T2 weighted SE sequence in this study. CT, as well as MRI, identified abnormalities in liver parenchyma in all patients. As far as detection of hepatic lesions is concerned, MRI and CE-CT were equal in 35 cases and MRI was superior in the other four cases. However, CT remains the examination of choice for detection of focal lesions, due to the short examination time, the low cost and the superiority in detection of extrahepatic pathology.

Adolescent↗
PubMed1990

[Moyamoya. Diagnosis using MRI and NMR angiography].

A case of Moya-Moya disease confirmed by cerebral angiography in a 10-year-old girl is reported. Hypertrophic collateral circulation is easily visualized by MRI. MR angiography very accurately demonstrated the vascular obstruction and the collateral circulation. As MR angiography is not invasive, it promises to become a valuable alternative to conventional angiography in the diagnosis of Moya-Moya.

Arterial Occlusive Diseases↗
PubMed1990

CT and MRI in spinal meningeal cyst. Report of a case.

A case of meningeal cyst of the spinal canal in the lumbosacral region is described. A CT scan showed a soft tissue mass associated with bone erosion. Myelography and computerised tomographic myelography revealed a cyst filling with contrast and thus CSF containing. The diagnosis of meningeal cyst was confirmed in a non-invasive way by MRI showing a mass with the same signal intensities as CSF on both T1 and T2 weighted images. Final characterisation of meningeal cysts in one of the three categories comprising spinal extradural meningeal cyst without spinal nerve root fibers (type I), spinal extradural meningeal cyst with spinal nerve root fibers (type II) and intradural meningeal cyst (type III) is impossible without operative inspection and histological examination.

Aged↗
PubMed1989

Generalized cortical dysplasia manifested by diffusely thick cerebral cortex.

Unilateral or bilateral rolandic macrogyria has been described as a cause of epilepsy and, in some cases, retardation. Tissue from the periphery of these lesions shows the changes of focal cortical dysplasia. Evidence reported herein suggests that cortical dysplasia may also be generalized. Two patients with intractable epilepsy and mental retardation had diffusely abnormal, thick cortex, shallow gyri, and poor demarcation of gray and white matter. One patient had an anterior callosotomy that led to considerable improvement of the epilepsy. Cortical layers 5 and 6 could not be differentiated on biopsy material. The white matter was poorly myelinated and contained clusters of heterotopic neurons. This syndrome, a congenital disorder of neuronal migration, with prolonged survival, represents a mild form of lissencephaly. It can be diagnosed during life by computed tomography or magnetic resonance scanning.

Adolescent↗