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Biomedical subjects

R Limet

Publications and source records attributed to R Limet.

At least 145 records · Page 8Linked to original sources
PubMed1997

Spinal ischaemia after surgery for abdominal infrarenal aortic aneurysm. Diagnosis with nuclear magnetic resonance.

A 76-year-old man underwent surgery for an infrarenal aortic aneurysm reaching 6 cm in maximal transverse diameter. The aorta was crossclamped below the level of the renal arteries. A tube graft was interposed and tend between the infrarenal aorta and the aortic bifurcation. Due to leakage on the suture line two consecutive episodes of crossclamping for a total duration of 40 min. were required. No hypotension was noted during or after the procedure. After operation, the patient complained of difficulties to move both legs and neurologic examination demonstrated paraparesis, with mild sensory deficit. Faecal and urinary incontinences were also noted and urodynamic testing demonstrated sphincterovesical palsy. Nuclear magnetic resonance imaging detected an ischaemic zone in the spinal cord at the level of T11. Faecal incontinence and motor deficit partially resolved but no bladder function recovery was observed. Spinal ischaemia is a rare complication after abdominal aortic surgery. Several risk factors have been suggested which include level and duration of the aortic crossclamping, possible interruption of the spinal cord blood supply via the greater medullary artery (the so-called artery of Adamkiewicz), presence of intra- or postoperative episodes of hypotension, atheromatous embolization, underlying occlusive arteriosclerosis of spinal arteries, and respect or not of the hypogastric circulation. In our case, the duration of the crossclamping and interruption of the blood flow in lumbar arteries probably supplying the distal spinal cord were likely contributive factors.

Aged↗
PubMed1997

[Mechanism of the growth and rupture of abdominal aortic aneurysm].

The relationship between atherosclerosis and abdominal aortic aneurysm development is well known. Atherosclerosis cannot explain the whole mechanism. Genetic characters of mechanisms leading to abdominal aortic development is obvious from this study and others. Our study evidences an increased metalloproteases activity in aortic wall proportionally to the size of the abdominal aortic aneurysm. A decrease of aortic wall elastin is evidenced proportionally to the AAA size. Extractable collagen is significantly increased in the aortic wall of patients operated on for aortic rupture.

Age Factors↗
PubMed1997

[Lymphatic, hepatic and osseous metastasis of a carotid chemodectoma. Apropos of a case].

A case of malignant carotid body tumor with nodal, hepatic and bone metastases is reported. Carotid body chemodectomas are slow-growing tumors which invade local structures. These tumors are usually benign but can occasionally produce local and distant metastases. Development of metastatic localizations is the only formal proof of malignancy as histology cannot distinguish between benign and malignant chemodectomas. Bilateral carotid arteriography gives the diagnosis. Surgery is the basis of treatment and should be performed early in the course to limit operative complications. Radiotherapy can be given as adjuvant treatment.

Angiography↗
PubMed1996

Acute diverticulitis in heart transplant recipients.

Immunosuppressed patients are susceptible to complicated diverticulitis, but reports of this complication are scarce in heart graft recipients. To estimate the prevalence of acute diverticulitis in heart graft recipients, we retrospectively reviewed the cases of diverticulitis in a series of 143 patients who underwent orthotopic heart transplantation in a period of 10 years. Six (4%) of these developed acute diverticulitis and required colectomy. All of them were male patients and were older than 50 years. Four patients underwent urgent laparotomy and colon resection with end colostomy (Hartmann procedure). The two other patients suffered from diverticulitis without generalized peritonitis and underwent laparoscopic sigmoidectomy with direct transanal end-to-end anastomosis. The postoperative outcomes of these six patients were satisfactory. As are other immunosuppressed patients, heart graft recipients are susceptible to diverticulitis. Early surgical management may be safe in well-compensated patients.

Abscess↗
PubMed1996

Activated forms of MMP2 and MMP9 in abdominal aortic aneurysms.

PURPOSE: This consistent observation of a reduction of the elastin concentration in abdominal aortic aneurysms (AAAs) has led us to investigate in AAA specimens two metalloproteinases that display elastase activity, MMP2 (gelatinase A/72kDa) and MMP9 (gelatinase B/92 kDa). METHODS: Samples of full-thickness aortic wall, adherent thrombus, and serum were collected in 10 patients with AAAs. Samples of normal aortic wall and serum were taken from 6 age-matched control patients. Quantitative gelatin-zymography and gelatinolytic soluble assays after acetyl-phenyl mercuric acid activation were performed on serum and tissue extracts, and the results were expressed in units on a comparative wet-weight basis. Histologic analysis was performed in parallel to score the inflammatory infiltrate. RESULTS: The luminal and parietal parts of the thrombus contained, respectively, 20- and 10-fold more gelantinolytic activity than the serum. The predominate form was MMP9. Although the total gelatinolytic activity was in the same range both in AAAs and in normal walls, a significantly higher proportion of MMP9 was found in the aneurysmal aortic walls. Furthermore, a significant proportion of MMP9 was under its processed active form, which was never observed in normal samples. A significantly higher proportion of MMP2 was also present as processed active form in AAA wall. This latter parameter positively correlated with the inflammatory score. CONCLUSIONS: The presence of activated MMP9 and MMP2 might contribute to the degradation of the extracellular matrix proteins that occurs during the development of aneurysms.

Aged↗
PubMed1996

Reversal of acute renal failure by kidney revascularisation.

OBJECTIVES: To assess whether acute renal failure, due to total or subtotal renal artery occlusion, can be reversed by kidney revascularisation. DESIGN: A retrospective review of surgery for kidney salvage in anuric patients at a University Hospital. METHODS: From 1983 to 1993, eight patients were operated on for occlusive renal artery disease as a cause of acute renal failure, requiring preoperative haemodialysis. On admission the mean serum creatinine was 40 mg/l (354 mumol/dl). The oligoanuria lasted from 12 h to 3 weeks. Renal length of 8 cm or more and visualisation of a patent distal renal artery branches on aortography were arguments that return of renal function could be expected after revascularisation of these non-functioning kidneys. RESULTS: Revascularisation restored immediate urine flow in six cases, with no further need for dialysis in four. Two patients remained oliguric despite successful reperfusion. One of them could be weaned from dialysis after 1 month. Two patients died postoperatively. Five of the eight patients left the hospital with restored renal function. CONCLUSIONS: Patients with acute renal function deterioration due to ischemia of a single or both kidneys can benefit from prompt revascularisation, with significant recovery of renal function in most of them.

Acute Kidney Injury↗
PubMed1996

Type II to type I transformation of chronically stimulated goat latissimus dorsi muscle: a histoenzymological, biochemical, bioenergetic, and functional study.

Five goat latissimus dorsi muscles (LDM) were submitted to a progressive chronic electrostimulation program to reach an integrated understanding of the fast-to-slow transformation process in large mammals. LDM were regularly sampled and followed during a period of 8 months. Each sample was simultaneously assessed for histoenzymological study, myosin and LDH isoforms and bioenergetic capacities [NADH dehydrogenase cytochrome c oxidoreductase (NADH Cyt c OR), succinate dehydrogenase cytochrome c oxidoreductase (Succ Cyt c OR), cytochrome c oxidase (Cyt c Ox) and LDH]. Such muscles were also tested with and without completion of II to I transformation for their mechanical properties in isometric and isotonic strain gauge testing. The conversion of fast-to-slow myosin monitored by heavy chain (HC I) and light chain slow component (LC2s) began a few days after stimulation and was almost 100% after 100 days. The H-LDH isoforms evolved similarly but did not reach 100% conversion after 200 days. The activity of respiratory chain oxidases increased within 36 h but to a variable extent and peaked after 32 days, corresponding to a 75% transformation of myosin compared to initial levels. NADH Cyt c OR, Succ Cyt c OR, and Cyt c Ox, respectively increased 10-, 5- and 5-fold. These activities then significantly decreased before the completion of the myofibrillar transformation and reached a plateau with stable activities that remained 2- to 3-fold higher than the unstimulated LDM. LDH activity sharply decreased until day 62 (5-fold) and then plateaued. Functionally, muscle showed a reduced speed of contraction and moderate reduction in power output but had become fatigue-resistant. This study documents the transformation process in large mammals and suggests the dynamic relation between workload, aerobic-anaerobic metabolism and the contractile myofibrillar system.

Animals↗
PubMed1996

Evaluation of the solitary pulmonary nodule by positron emission tomography imaging.

Current noninvasive imaging methods are not sufficiently reliable for accurate detection of malignancy in most solitary pulmonary nodules (SPNs). Positron emission tomography (PET) using 18-fluorodeoxyglucose (FDG), showing increased FDG uptake and retention in malignant cells, has proved useful to differentiate malignant from benign tissue and could, therefore, contribute to the evaluation of the SPN. We performed a prospective study of 50 patients referred to the Pneumology Department with unclear diagnoses of SPN after conventional radiological screening. PET study was performed on each subject before an invasive procedure was proposed. Thirty three patients had a malignant nodule and 17 had a benign nodule. The mean size of malignant nodule was 3 cm (range 1.5-4.5 cm). All showed a marked increase in 18-FDG uptake. The mean size of benign nodule was 1.8 cm (range 0.5-3.5 cm). PET imaging showed the absence of 18-FDG uptake and correctly identified 15 of 17 benign nodules. There was two false-positive cases with a moderate increase in 18-FDG uptake (1 postprimary tuberculosis; and 1 anthracosilicotic nodule with nonspecific inflammation). At present, the sensitivity and specificity of the method are 100 and 88%, respectively. The positive and negative predictive values of PET imaging for SPNs are 94 and 100%, respectively. Our preliminary results demonstrate that PET-FDG imaging is a noninvasive technique, which appears highly accurate in differentiating malignant SPN from benign SPN.

Aged↗
PubMed1996

Staging of the mediastinum: value of positron emission tomography imaging in non-small cell lung cancer.

Recent studies have shown limitations of morphological imaging in staging mediastinal lymph node involvement in lung cancer. In contrast to computed tomography (CT), which depends primarily on anatomical imaging features, positron emission tomography (PET) with 18-fluorodeoxyglucose (FDG) depends mainly on the metabolic characteristics of a tissue for the diagnosis of disease. We have performed a prospective study comparing FDG-PET and CT of the thorax in the presurgical assessment of the mediastinum in 50 patients with newly diagnosed non-small cell lung cancer (NSCLC). CT and PET scans were interpreted separately, and results were compared to pathological staging obtained during thoracotomy. Hilar or mediastinal lymph node involvement was present in 58%. In staging for lymph node involvement, CT had a sensitivity of 72% and specificity of 81%, whereas PET had a sensitivity and specificity of 90% and 86%, respectively. When the PET study was compared to histological results, there were four cases showing more advanced mediastinal involvement with PET and four cases showing less involvement with PET. From our preliminary results, we conclude that positron emission tomography with 18-fluorodeoxyglucose is significantly more accurate than computed tomography in the mediastinal staging of non-small cell lung cancer.

Aged↗
PubMed1996

Kinking of the internal carotid artery: clinical significance and surgical management.

The authors report on 62 surgical corrections for kinking of the internal carotid artery during a 13-year period (1980-1993). This represents 2.8% of all carotid operative procedures (n = 2188) in the same period. It always concerned a significant (< 60 degrees) angulation of a redundant internal carotid artery, that in all but 3 cases was associated with atherosclerotic involvement of the carotid bifurcation. The indication to surgery included transient hemispheric or ocular ischaemia in 25.5% of cases, a regressive neurologic deficit in 8%, a minor stroke in 3%, a stroke in evolution in 11%, and non-lateralized cerebral ischaemia in 21%. In 19 patients (31%) it concerned an asymptomatic high degree stenosis. The surgical technique consisted in carotid transposition-reimplantation after eversion endarterectomy in 37 cases, in posterior transverse plication with patch angioplasty in 20 cases, and in segmental excision with venous interposition graft in 5 cases. There was one postoperative death. The morbidity include one ipsilateral non-fatal stroke and 3 transient ischaemic attacks. A complete long-term follow-up (mean duration 3.4 years) is available for 57 patients. The late incidence of stroke is 1.5% per year. The 5-year survival attains 67%. These long-term results are comparable to the outcome of standard endarterectomy in the same institution. The authors discuss the indication, techniques, and outcome of surgical correction of kinked internal carotid artery. They recommend a shortening procedure, often associated with endarterectomy for severely kinked vessels (angulation 60 degrees or less), symptomatic or not.

Aged↗
PubMed1996

Laparoscopic-assisted colectomy in heart transplant recipients.

Reports of laparoscopy in heart graft recipients are scarce and, to our knowledge, laparoscopic colectomy has not yet been reported in heart transplant patients. The magnitude and the tolerance of the hemodynamic changes induced by pneumoperitoneum are unknown in heart graft recipients, who have a denervated heart and are "preload-dependent". The authors report the clinical courses of 2 heart graft recipients who developed acute diverticulitis without perforation or peritonitis and who underwent laparoscopic-assisted colectomy without complications.

Abscess↗
PubMed1996

Carotid surgery in octogenarians: is it worthwhile?

Controversy surrounds the role of carotid endarterectomy in octogenarians. Although the prognosis of severe degree carotid stenosis is more ominous in the elderly, operative risk seems more important in the aged. To evaluate the presumed detrimental effect of advanced age on the mortality-morbidity of carotid endarterectomy, the authors reviewed their common experience with carotid surgery in patients aged 80 years or more. From 1980 to 1994, 129 octogenarians were operated on for occlusive carotid artery disease in two university hospitals. The data for these patients, 80 years of age and older (group 1) are compared to these for a large middle age group (less than 80 years) (group 2) operated by the same surgeons during that period. The baseline characteristics of both groups were similar, except for smoking, diabetes and previous myocardial revascularization, more prevalent in the younger age group. In the elderly group prophylactic surgery for asymptomatic stenosis was done in 36%, versus 40% of the middle aged patients, and for stroke in evolution in 8% versus 4% (p < 0.05). The perioperative stroke rate was 0.8% in the group older than 80 years, compared to 1.2% for non octogenarians (NS). The operative mortality was similar for both age groups (2.3 and 1.5 respectively). The long-term results gave a similar outlook for both age groups. The 5-year stroke-free rate reached 89% for group 1 versus 91% for group 2. The 5-year survival rate, however, was less for the elderly patients (47% versus 77%, mean follow-up periods of 30 and 49 months). These results suggest that carotid endarterectomy can be safely done in elderly patients, with a similar risk/benefit ratio as for the younger patients. Advanced age, by itself, is not to be considered as contraindication to carotid surgery.

Adult↗