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Biomedical subjects

G Marchal

Publications and source records attributed to G Marchal.

At least 433 records · Page 24Linked to original sources

Prolonged positive contrast enhancement with Gd-EOB-DTPA in experimental liver tumors: potential value in tissue characterization.

To evaluate the potential of the hepatobiliary magnetic resonance (MR) imaging contrast agent gadolinium EOB-DTPA (ethoxybenzyl diethylenetriaminepentaacetic acid) for the characterization of hepatic tumors, 79 primary and six implanted hepatomas in 38 rats were studied. MR imaging findings after administration of Gd-DTPA (0.3 mmol/kg) and Gd-EOB-DTPA (30 mumol/kg) were correlated with microangiographic and histologic findings. Gd-EOB-DTPA produced a strong liver enhancement, which caused prompt negative contrast enhancement (CE) in all implanted hepatomas and in 77 of 79 primary hepatomas. A positive CE that lasted up to 2 hours was found in two of 79 primary hepatomas, both of which were highly differentiated (grade I) hepatocellular carcinomas (HCCs). The rest were moderately differentiated to undifferentiated HCCs (grades II-IV). Rim enhancement, which corresponded histologically to peritumoral malignant infiltration sequestering normal hepatocytes, was seen around all implanted and some primary hepatomas. Positive tumor CE after administration of Gd-EOB-DTPA in this study is much less frequent but much more specific in comparison with the results of previous studies with manganese-DPDP (N,N'-dipyridoxylethylenediamine-N,N'-diacetate 5,5'-bis[phosphate]). These findings may help further discriminate hepatic tumors.

Animals↗

Haematological findings in type Ib glycogen storage disease before and after portacaval shunt.

Persistent neutropenia and repeated respiratory infections were documented in a girl with glycogen storage disease type Ib. A termino-lateral portacaval shunt resulted in normalisation of the granulocyte counts and disappearance of the recurrent infections. The platelet dysfunction that was apparent before surgery, was also corrected by the shunting procedure. A marked hypochromic anaemia, however, probably caused by a sequestration of iron in the spleen and resistant to therapy, remains a persistent feature in this patient.

Anemia, Hypochromic↗

Insulinoma with hypoglycemia and normal immunoreactive insulin but with an insulin-like activity restricted to the portal vein.

In a 46-year old Caucasian woman, the authors report a B-cell adenoma with plasma immunoreactive insulin (IRI) ranging from 10 to 32 microunits/ml, despite severe spontaneous hypoglycemia. In a peroperative sample withdrawn from the portal vein, normal IRI (40 micromicron/ml) in the presence of high insulin-like activity (290 microunits/ml) was observed by using a biological assay performed on rat epididymal fat tissue. Furthermore, this material did not cross-react with insulin antibodies and was undetectable in systemic venous samples. Although further identification by chromatographic extraction was not performed, the substance secreted by the tumor is probably identical to the non-suppressible insulin-like activity (NSILA) isolated by Froesch and responsible for hypoglycemia in a few cases of extrapancreatic tumors. The absence of this material in systemic samples indicates an immediate removal by a single passage through the liver.

Adenoma, Islet Cell↗

A review of the general aspects of radiofrequency ablation.

As an alternative to standard surgical resection for the treatment of malignant tumors, radiofrequency ablation (RFA) has rapidly evolved into the most popular minimally invasive therapy. To help readers gain the relevant background knowledge and to better understand the other reviews in this Feature Section on the clinical applications of RFA in different abdominal organs, the present report covers the general aspects of RFA. After an introduction, we present a simple definition of the energy applied during RFA, a brief historical review of its technical evolution, and an explanation of the mechanism of action of RFA. These basic discussions are substantiated with descriptions of RFA equipment including those commercially available and those under preclinical development. The size and geometry of induced lesions in relation to RFA efficacy and side effects are discussed. The unique pathophysiologic process of thermal tissue damage and the corresponding histomorphologic manifestations after RFA are detailed and cross-referenced with the findings in the current literature. The crucial role of imaging technology during and after RFA is also addressed, including some promising new developments. This report finishes with a summary of the key messages and a perspective on further technologic refinements and identifies some specific priorities.

Abdominal Neoplasms↗

Repositioning and leaving in situ the central venous catheter during percutaneous treatment of associated superior vena cava syndrome: a report of eight cases.

PURPOSE: To describe a combined procedure of repositioning and leaving in situ a central venous catheter followed by immediate percutaneous treatment of associated superior vena cava syndrome (SVCS). METHODS: Eight patients are presented who have central venous catheter-associated SVCS (n = 6 Hickman catheters, n = 2 Port-a-cath) caused by central vein stenosis (n = 4) or concomitant thrombosis (n = 4). With the use of a vascular snare introduced via the transcubital or transjugular approach, the tip of the central venous catheter could be engaged, and repositioned after deployment of a stent in the innominate or superior vena cava. RESULTS: In all patients it was technically feasible to reposition the central venous catheter and treat the SVCS at the same time. In one patient flipping of the Hickman catheter in its original position provoked dislocation of the released Palmaz stent, which could be positioned in the right common iliac vein. CONCLUSION: Repositioning of a central venous catheter just before and after stent deployment in SVCS is technically feasible and a better alternative than preprocedural removal of the vascular access.

Catheterization, Central Venous↗

Iatrogenic pseudoaneurysm in the upper arm: treatment by transcatheter embolization.

A 32-year-old woman presented with a pulsatile, painful mass in her left upper arm, originating several days after removal of an Ilizarov external fixation. The diagnosis of a pseudoaneurysm was made by medical history and by physical and ultrasonographic examination of the mass. Angiography confirmed the presence of the pseudoaneurysm, originating from a branch of the arteria profunda brachii, and definitive treatment was performed by transcatheter embolization. Clinical follow-up showed absence of pulsation and pain in the upper arm and a gradual volume decrease of the mass lesion.

Adult↗

The angiographic incidence of renal artery stenosis in the arteriosclerotic population.

The incidence of renal artery stenosis was evaluated with intra-arterial digital subtraction angiography in 100 consecutive patients referred for peripheral arteriopathy. Fifty-seven patients were normotensive, 43 were hypertensive. In the normotensive group, renal artery stenosis was found in ten patients (17.5%). In the hypertensive group renal artery stenosis was found in twelve patients (28%). It is concluded that the incidence of renal artery stenosis is high in an arteriosclerotic population both in normotensive and hypertensive patients.

Angiography, Digital Subtraction↗

Intravascular ultrasonography, a new alternative for the assessment of vascular lesions.

Intravascular ultrasonography (IVUS) was performed in ten patients undergoing a diagnostic or therapeutic angiography. The ultrasound probe was inserted in a 6 French catheter and introduced through a 7 or 8 French sheath. Exact information was yielded about the extent of arteriosclerosis, the stenotic process and the composition of the atheromatous plaque (soft plaque or presence of calcifications). In the patients undergoing a percutaneous transluminal angioplasty, the status after dilation was also assessed, and intimal tears and residual atheromatous plaques could well be evaluated.

Angioplasty, Balloon↗

Assay for quantitation of mature monocytes in murine haemopoietic tissues.

We propose a new assay which allows the extent of production of mature monocytes in murine haemopoietic tissues to be monitored with precision. To develop such a quantitative assay, we chose a T-cell function easily detectable in vivo, namely the ability of T lymphocytes to locally transfer a delayed-type hypersensitivity (DTH) reaction. T cells co-transferred with antigen into footpads of syngeneic mice are mediators of DTH through their ability to recruit phagocytes recently produced in haemopoietic tissues. Therefore, if recipients of DTH-mediating T cells (DTH-T cells) are depleted of phagocytes by lethal irradiation given 36 to 48 h before local transfer of these DTH-T cells mixed with antigen, they no longer respond by a DTH reaction, measured as an increase in footpad thickness, unless they receive i.v. bone marrow cells as a source of recruitable phagocytes. In such conditions, the footpad thickness increase is linearly related to the number of cells injected i.v. Pretreatment of bone marrow cells with the rat IgG2b F4/80 monoclonal antibody abolishes their ability to restore expression of DTH, indicating that monocytes (F4/80+ cells) are the phagocytes to be measured. This assay system thus provides a means of measuring levels of recruitable mature monocytes present in haemopoietic tissues. One illustration of the assay is given by the study of the recovery of recruitable phagocytes in bone marrow following a single treatment with cyclophosphamide.

Animals↗