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Biomedical subjects

V Nicolas

Publications and source records attributed to V Nicolas.

At least 19 recordsLinked to original sources
PubMed1999

Nonsurgical reconstruction of thoracic aortic dissection by stent-graft placement.

BACKGROUND: The treatment of thoracic aortic dissection is guided by prognostic and anatomical information. Proximal dissection requires surgery, but the appropriate treatment of distal thoracic aortic dissection has not been determined, because surgery has failed to improve the prognosis. METHODS: We prospectively evaluated the safety and efficacy of elective transluminal endovascular stent-graft insertion in 12 consecutive patients with descending (type B) aortic dissection and compared the results with surgery in 12 matched controls. In all 24 patients, aortic dissection was diagnosed by magnetic resonance angiography. In each group, the dissection involved the aortic arch in 3 patients and the descending thoracic aorta in all 12 patients. With the patient under general anesthesia, either surgical resection was undertaken or a custom-designed endovascular stent-graft was placed by unilateral arteriotomy. RESULTS: Stent-graft placement resulted in no morbidity or mortality, whereas surgery for type B dissection was associated with four deaths (33 percent, P=0.09) and five serious adverse events (42 percent, P=0.04) within 12 months. Transluminal placement of the stent-graft prosthesis was successful in all patients, with no leakage; full expansion of the stents was ensured by balloon inflation at 2 to 3 atm. Sealing of the entry tear was monitored during the procedure by transesophageal ultrasonography and angiography, and thrombosis of the false lumen was confirmed in all 12 patients after a mean of three months by magnetic resonance imaging. There were no deaths or instances of paraplegia, stroke, embolization, side-branch occlusion, or infection in the stent-graft group; nine patients had postimplantation syndrome, with transient elevation of C-reactive protein levels and body temperature plus mild leukocytosis. All the patients who received stent-grafts recovered, as did seven patients who underwent surgery for type B dissection (58 percent) (P=0.04). CONCLUSIONS: These preliminary observations suggest that elective, nonsurgical insertion of an endovascular stent-graft is safe and efficacious in selected patients who have thoracic aortic dissection and for whom surgery is indicated. Endoluminal repair may be useful for interventional reconstruction of thoracic aortic dissection.

Adult↗
PubMed1999

Systemic effects and side effects of interstitial techniques used in liver tissue.

BACKGROUND: Percutaneous ethanol injection (PEI) and cryosurgery are increasingly used for the treatment of liver malignancies. To create a safety margin and to destroy completely diffusely growing tumors, the precise destruction of healthy liver tissue is necessary. Little is known about the effects of operating on this type of tissue. This study evaluated the effects and side effects of PEI and cryosurgery when applied to normal parenchyma of the liver. STUDY DESIGN: Two groups of six minipigs each were treated with either PEI or cryosurgery to create necrosis in the liver. During and after the procedures, vital signs were monitored and necrotic areas were observed by ultrasonography. Standard and immunohistochemistry stains were made from samples of the necrosis, the liver, and the lung. RESULTS: In the PEI group, thromboembolic complications occurred in all animals (fatality rate 50%). Hematogenous spread of hepatocytes was demonstrated by immunohistochemistry and was a cause of pulmonary embolism. In the cryosurgery group, neither specific complications nor signs of cell spillage occurred. Because of an isolating effect of blood perfusion, hepatocytes close to the portal triads were less damaged, vital cells were present in the periphery, and the necroses were smaller than the induced lesions. CONCLUSIONS: The effect of PEI in healthy liver tissue is unpredictable. This makes the creation of a safety margin or the treatment of a diffusely infiltrating tumor impossible. PEI always introduces the risk of hematogenous cell spread. Effects of cryosurgery are less dependent on tissue qualities. In both techniques, the real extent of complete tissue destruction cannot be visualized by ultrasonography.

Animals↗
PubMed1999

Preformulation: effect of moisture content on microcrystalline cellulose (Avicel PH-302) and its consequences on packing performances.

This study evaluates the influence of moisture content on the packing performances of a new grade of microcrystalline cellulose (MCC) (Avicel PH-302) either by classical method or by an unconventional compression technique (constant volume reduction of powder bed). An increase in moisture content decreases the apparent density of the powder bed, resulting from interparticulate friction enhancement. This modification of apparent density seems to be the main effect caused by the presence of humidity, which explains the variations of compression properties, like an increase of powder plasticity generally observed in the experimental conditions.

Cellulose↗
PubMed1998

[Intramural hemorrhage of the thoracic aorta].

PURPOSE: Intramural hemorrhage (IMH) of the aorta is considered to be a possible preliminary stage to dissection. We report on our experience with MRI, CT, and TEE in the diagnosis as well as in the correct evaluation of the extent of an IMH. METHOD: Between 1983 and 1997 a total of 26 patients were examined using MRI (n = 13) and/or contrast enhanced CT (n = 18) or TEE. The validation was effected in 17 cases through intraoperative or postmortem inspection and in the remaining cases either through continuous clinical or radiological monitoring (n = 6) or through the depiction of the results in 2 different imaging procedures (n = 3). RESULTS: The correct diagnosis of an IMH was made on all examined patients with all imaging modalities. In all cases, MRI enabled the correct identification of the affected aortic segments. Using CT the affected descending aorta was overlooked in one out of 15 cases; TEE failed in one out of two cases of intramural hemorrhage in the aortic arch. A false positive diagnosis was made with CT in one out of 9 cases in the ascending aorta, and using sonography, this occurred in two out of 3 cases in the area of the aortic arch. CONCLUSION: According to our experience, magnetic resonance imaging is the most accurate method for the diagnosis of an IMH.

Adult↗
PubMed1998

[Value of MRI, CT and findings in staging of gynecologic malignancies].

PURPOSE: The present study was designed to compare the value of MRI, CT and clinical examination in local tumor staging of gynaecologic malignancies. PATIENTS AND METHODS: 99 patients with clinically suspected carcinoma of the cervix uteri, ovarian carcinoma or tumor recurrence after gynaecologic cancer underwent all three staging modalities. Furthermore CT and MRI were compared in detecting lymph node metastasis and peritoneal implants. RESULTS: MRI was superior to CT and clinical staging in local tumor staging with an accuracy of 77% for cervical carcinoma and of 88% for recurrent tumors, whereas CT achieved an accuracy of 65% and 55% and clinical staging 60% and 63% accuracy for carcinoma of the cervix and recurrent cancer. Especially for local staging of these two tumor entities MRI is very useful. MRI and CT reached comparable results in the detection of ovarian tumors with an accuracy of 73% for MRI and 69% for CI. Both imaging modalities also showed equal results in the detection of lymph node metastasis, so that primary the cost saving use of CT tumor staging for ovarian lesions and lymph node metastasis should be favoured.

Female↗
PubMed1997

[Femoral arteriovenous fistula and transplant malfunction after allogeneic kidney transplantation. A case report].

This case report deals with the clinical history of a 52-year-old woman who suffered from delayed graft function and ischaemic pain after a technically successful renal transplantation. The past history of the patient revealed that coronary catheters had repeatedly been used for investigation and treatment of myocardial infarctions. The clinical investigation reported here revealed a typical auscultatory result with an arteriovenous (AV) fistula in the right upper limb. After performing a digital arterial angiography, an AV fistula between the femoral artery and vein was demonstrated. Operative occlusion of the fistula increased the perfusion of the kidney graft and the right limb. The patient recovered without wound infection and could leave the hospital with the transplanted kidney functioning well. This case report demonstrates that persistence of AV fistulas after angiographic investigations is rare. Operative occlusion of these lesions should be performed before kidney transplantation to avoid steal phenomena and disturbed would healing.

Angiography, Digital Subtraction↗
PubMed1997

Hilar traumatic neuroma after liver transplantation.

We report our first case of symptomatic traumatic neuroma in the liver hilum after orthotopic liver transplantation. Compression of the hepatic artery caused extraluminal obstruction and resulted in perfusion damage to the graft. Moreover, intimal hyperplasia of the hepatic artery was present. Retransplantation was necessary because the hepatic artery was not salvageable. Potential pathophysiological mechanisms for these findings are discussed.

Adult↗
PubMed1997

[CT and supplementary HR-CT of Kaposi's sarcoma of the pulmonary parenchyma--the morphology of the findings and the diagnostic value].

AIM OF THE STUDY: was an analysis of the CT appearances of Kaposi's sarcoma (KS) in the lung and to determine the diagnostic value of CT and supplementary high resolution CT. MATERIALS AND METHOD: 38 AIDS patients with cutaneous and/or mucocutaneous KS were examined by conventional radiography and CT of the chest during a prospective study. RESULTS: Evaluation of the CT appearances in 16 patients with proven pulmonary KS showed a typical pattern consisting of patchy and flame-shaped infiltrates in relation to the bronchovascular bundle these may be combined with non-necrotic confluent shadows surrounded by areas of ground glass opacity, thickened interlobular septa and round foci. In 12 patients the CT appearances were regarded as characteristic and in four as suggestive but not diagnostic. CONCLUSION: Combination of these features in patients with cutaneous or mucocutaneous manifestations but otherwise negative findings of pulmonary infection allows one to make a diagnosis of pulmonary KS with a high degree of certainty and helps to avoid invasive diagnostic procedures.

Adult↗
PubMed1997

[The significance of the arterial vascular supply of segment IV in living liver donation].

PURPOSE: Postoperative CT's in living liver donors were analysed retrospectively to examine whether atrophies of segment IV occur after procurement depending on arterial vascular supply. PATIENTS AND METHODS: Postoperative CT's from 19 living donors were retrospectively analysed. DSA of the upper abdomen had been performed on all donors prior to donation. RESULTS: The pre-operative DSA images demonstrated an arterial vascular supply of segment IV from the right hepatic artery in 10/19 cases, from the left hepatic artery in 7/19 cases and from both, left and right hepatic artery, in 2/19 cases. Atrophies were seen in 3/7 patients in which segment IV was perfused via left hepatic artery, in further two patients with perfusion from the right hepatic artery or from both sides respectively. Clinically only one patient presented with an abscess. CONCLUSIONS: The patterns of vascular supply to segment IV seen in our patients differ from those published by Couinaud. Since only 3/7 patients with an arterial supply from the left hepatic artery developed a segmental atrophy, we conclude that there must be additional, radiologically not identifiable portal venous branches or collaterals from the right portal vein that maintain perfusion of segment IV.

Adult↗
PubMed1997

Prospective randomized study of drainage and resection on non-occlusive segmental portal hypertension in chronic pancreatitis.

BACKGROUND: In chronic pancreatitis, compression of the splenic vein and superior mesenteric vein (SMV) by an inflammatory mass may cause segmental portal hypertension. Drainage and resection are the principles of surgery for chronic pancreatitis. This study was devised to evaluate the effect of drainage and resection on venous splanchnic blood flow in patients with non-occlusive segmental portal hypertension. METHODS: In 14 of 30 patients with chronic pancreatitis predominantly involving the pancreatic head, segmental portal hypertension due to compression of the splenic vein and SMV was detected by means of indirect splenomesentericoportography and Doppler ultrasonography. None of these 14 patients had symptomatic gastric fundic varices. They were allocated randomly to surgical drainage or resection. Median follow-up was 30 (range 12-48) months. RESULTS: In the resection group, mean(s.d.) splenic vein blood flow increased from 316(46) ml/min before operation to 396(57) ml/min at follow-up (P < 0.01). In the drainage group, preoperative splenic vein blood flow (318(37) ml/min) was not increased after operation (322(37) ml/min). Mean(s.d.) SMV flow increased from 292(42) ml/min before operation to 436(64) ml/min at follow-up (P < 0.01) in the resection group. In the drainage group mean(s.d.) SMV blood flow was 296(32) ml/min before operation and 314(34) ml/min at follow-up. No patient developed fundic gastric varices during follow-up. CONCLUSION: In non-occlusive segmental portal hypertension due to chronic pancreatitis, resection, but not drainage, restores normal venous splanchnic blood flow.

Adult↗
PubMed1997

[Computerized tomography of retroperitoneal liposarcoma].

Besides the malignant fibrous histiocytoma, liposarcoma is one of the most common soft-tissue sarcomas seen in adults. They are most often localized in the lower extremity, followed by sarcomas in the retroperitoneal space which differ from the former in clinical appearance, epidemiology, and prognosis. The prognosis is especially dependent on tumor histology which is mainly classified into four subtypes. The aim of the study was to investigate whether there are specific CT-features for each histologic subgroup, by analyzing the examination of 20 patients. The highest percentage in fat and the biggest tumors were seen with well-differentiated liposarcomas (n = 4), whereas myxoid ones (n = 6) showed the sharpest margins. Round-cell (n = 2) and pleomorphic (n = 5) and pleomorphic (n = 5) types showed mainly soft-tissue attenuation and could not be differentiated, either from each other or from other soft-tissue tumors. A clear identification of the histologic subgroup does not seem to be possible.

Adult↗
PubMed1997

Antiproliferative effect of Pygeum africanum extract on rat prostatic fibroblasts.

The effect of a Pygeum africanum extract (Tadenan) (Pa), used in the treatment of micturition disorders associated with BPH, has been examined on the proliferation of rat prostatic stromal cells stimulated by different growth factors. EGF, bFGF, and IGF-I but not KGF are mitogenic for prostatic fibroblasts in culture. Pygeum africanum inhibits both basal and stimulated growth with IC50 values of 4.5, 7.7 and 12.6 micrograms./ml. for EGF, IGF-I and bFGF, respectively, compared to 14.4 micrograms./ml. for untreated cells, the inhibition being stronger towards EGF. Pygeum africanum inhibited the proliferation induced by TPA or PDBu in a concentration-dependent manner with IC50 values of 12.4 and 8.1 micrograms./ml. respectively. The antiproliferative effects of Pa were not ascribed to cytotoxicity. These results show that Pygeum africanum is a potent inhibitor of rat prostatic fibroblast proliferation in response to direct activators of protein kinase C, the defined growth factors bFGF, EGF and IGF-I, and the complex mixture of mitogens in serum depending on the concentration used. PKC activation appears to be an important growth factor-mediated signal transduction for this agent. These data suggest that therapeutic effect of Pygeum africanum may be due at least in part to the inhibition of growth factors responsible for the prostatic overgrowth in man.

Animals↗
PubMed1996

[Comparison of CT arterioportography and spiral CT arterioportography in malignant lesions of the liver].

PURPOSE: To determine the value of spiral CT during arterial portography (SCTAP) in detecting and localising focal liver lesions we compared the SCTAP findings to those gained by conventional CT during arterial portography (CTAP). MATERIAL AND METHODS: We evaluated a total of CT scans of 128 patients with 162 malignant lesions of the liver. 45 patients underwent SCTAP and 83 patients CTAP. Results of radiological studies were compared with surgical and pathological findings. RESULTS: The overall sensitivity of SCTAP was 93% with a sensitivity of 80% for lesions of less than 1 cm diameter. For CTAP the overall sensitivity was 88%, but the sensitivity for lesions smaller than 1 cm was only 53%. Although with SCTAP examination of hepatic vasculature and liver parenchyma was continuous, we found no advantage in the localisation of lesions to the liver segments compared to CTAP, and the sensitivity of localisation did not correlate with the size of lesions. CONCLUSION: In our study SCTAP turned out to be a reliable radiological method in the preoperative detection of focal liver lesions, with a high overall sensitivity. SCTAP showed improved sensitivity in the detection of small malignant lesions (< 1 cm) in comparison to CTAP.

Adult↗