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Biomedical subjects

M Leon

Publications and source records attributed to M Leon.

At least 73 records · Page 4Linked to original sources
PubMed1995

New insights into the pathophysiologic condition of venous ulceration with color-flow duplex imaging: implications for treatment?

PURPOSE: This study was conducted to investigate the distribution of reflux in the veins adjacent to or within the venous ulcer (local) and to correlate it with the pattern of disease of the axial veins (all veins away from the ulcer area) of the affected limb. METHODS: Forty-three ulcers in 34 legs of 33 patients were examined with color-flow duplex imaging. The veins in the area of the ulcer were scanned with a sterile technique. RESULTS: In 17 legs (50%) there was documented past deep venous thrombosis. All of the 34 limbs had reflux in the superficial or deep axial veins either alone or in combination. Fifteen of these limbs (44%) also had perforating vein incompetence, but none had perforator incompetence alone. Six ulcers showed no evidence of reflux in the local veins when scanned through the ulcer bed despite the presence of reflux in the axial veins of the limb. In 13 limbs with 17 ulcers, either the superficial axial veins alone or the deep axial veins alone were affected (with or without associated perforator incompetence). Examination of the local veins associated with these 17 ulcers revealed a similar pattern of reflux to that seen in the axial veins in 13 cases, with the remaining 4 ulcers showing no local venous abnormality. The pattern of reflux was less predictable at the local ulcer level in limbs where both superficial and deep venous incompetence coexisted in the axial veins. Only 7 of the 26 ulcers (27%) in these limbs had similar evidence of combined superficial and deep reflux in the local ulcer veins, whereas 10 ulcers (39%) were associated with local reflux in the superficial or deep veins alone. CONCLUSIONS: These data show that 86% (37/43) of the ulcers has some degree of reflux in the local area, the pattern of which may differ from the axial vein disease. Treatment of the local hemodynamic abnormalities may be an important factor in the healing of the ulcers and in the prevention of their recurrence.

Adolescent↗
PubMed1995

Colour flow duplex scanning in suspected acute deep vein thrombosis; experience with routine use.

OBJECTIVES: To determine the accuracy of colour flow Duplex scanning (CFDS) in the diagnosis of deep vein thrombosis (DVT) and subsequently to investigate its diagnostic value in patients who have normal deep veins despite symptoms. DESIGN: Prospective open clinical study. SETTING: Vascular laboratory and radiology departments of University Hospital. MATERIALS AND METHODS: In the first part 112 limbs in 103 patients, 94 with symptoms of acute DVT and nine with pulmonary embolism (PE) were examined prospectively with CFDS and venography. Subsequently, in the second part, 328 legs in 304 patients were examined by CFDS alone for acute symptoms of DVT or PE. MAIN RESULTS: DVT was detected in 55 limbs by venography: proximal DVT was seen in 23 limbs, distal DVT in 25 limbs and both proximal and distal in seven limbs. CFDS was 100% sensitive and 98.8% specific in detecting proximal DVT whereas its sensitivity and specificity was 87.5% and 98.7% for distal DVT. Positive and negative predictive values were over 95% for both limb segments. The overall accuracy for the proximal DVT was 99.4% and for the distal 93.1%. In the second part, CFDS alone detected DVT in 156 limbs (47.6%); DVT was in the proximal segment in 82, distal segment in 61 and both in 13. In 172 limbs other causes of symptoms were identified in 34 (20%). CONCLUSIONS: We have demonstrated that CFDS is as accurate as venography when used by experienced operators. The average time of examination is 15-20 minutes and compares favourably with venography. Other causes of leg symptoms can also be diagnosed by CFDS in around 20% of patients who are found to have normal veins.

Humans↗
PubMed1995

CLECOS_P: clinical evolution control system on Parkinsonian patients undergoing neural transplantation.

The CLECOS_P system was conceived for registering and automating the processing of clinical evaluations performed on patients with Parkinson's disease who undergo functional neurosurgery and/or neural transplant. CLECOS_P represents the first time a computerized system is able to offer--with high precision and considerable time-savings--an integral analysis of the evolutive behavior of the universe in integrated variables at the core assessment program for intracerebral transplantations (CAPIT). CAPIT is used internationally for the evaluation and follow-up of patients with this pathology who have undergone neural transplant. We used the so-called MEDSAC methodology for the preparation of this system. The methodology that was used for the design of an intelligent system aimed at medical decision-making was based on the quantitative analysis of the clinical evolution. At the present moment, there are 20 patients controlled by this system: 11 bilaterally transplanted, 9 unilaterally (registered in ranks of 3 months before operation up to 1, 2, 3, 6, 9, 12, 18, and 24 months after operation). The application of CLECOS_P to these patients permitted the evaluation of 400 clinical variables, where a better evolutive characterization of the patients was obtained, thus getting most favorable results with personalized therapeutic methods aimed at raising their quality of life. CLECOS_P is used in a multi-user environment on a local area network running Novell Netware version 3.11.

Brain Tissue Transplantation↗
PubMed1994

Inter-series differences in the restenosis rate of Palmaz-Schatz coronary stent placement: differences in demographics and post-procedure lumen diameter.

Restenosis rates following Palmaz-Schatz stenting vary between 13 and 36%. To determine whether the nearly three-fold interseries difference in restenosis rates reflects systematic factors (demographic and procedural variables such as post-treatment lumen diameter) rather than random variation, we pooled 486 lesions treated with the Palmaz-Schatz coronary stent in the U.S. Multicenter Registry (n = 259) with the single-center Beth Israel Hospital experience (n = 227) and analyzed the combined series using a continuous geometric model of restenosis. A greater proportion of lesions (66 vs. 50%; P < 0.001) in the Multicenter cohort represented restenosis after a prior intervention. The Multicenter experience also showed a smaller minimum lumen diameter following stent placement (2.61 vs. 3.43 mm; P < 0.001), higher post-stent percent stenosis (16 vs. -2%; P < 0.001), and less acute gain (1.79 vs. 2.67 mm; P < 0.001) than lesions treated in the Beth Israel cohort. At 6-month follow-up, the angiographic restenosis rate (> or = 50% diameter stenosis) was significantly higher in the Multicenter group (35 vs. 27%; P = 0.05), despite the development of less absolute late loss (0.96 vs. 1.32 mm; P < 0.001). Multivariable modeling, however, showed that the only independent predictors of restenosis were a post-procedure lumen diameter < 2.80 mm (odds ratio = 1.57; P = 0.04), diabetes mellitus (odds ratio = 3.55; P < 0.001), and prior restenosis (odds ratio = 1.84; P = 0.008).(ABSTRACT TRUNCATED AT 250 WORDS)

Cohort Studies↗
PubMed1994

Evidence of an oxidative challenge in the Alzheimer's brain.

Alzheimer's disease may arise from or produce oxidative damage in the brain. To assess the responses of the Alzheimer's brain to possible oxidative challenges, we assayed for glutathione, glucose-6-phosphate dehydrogenase, catalase and superoxide dismutase in twelve regions of Alzheimer's disease and aged control brains. In addition, we determined levels of malondialdehyde to evaluate lipid peroxidation in these brain regions. Most brain regions showed evidence of a response to an oxidative challenge, but the cellular response to this challenge differed among brain regions. These data suggest that the entire Alzheimer's brain may be subject to an oxidative challenge, but that some brain areas may be more vulnerable than others to the consequent neural damage that characterizes the disease.

Aged↗
PubMed1994

Percutaneous excimer laser coronary angioplasty: results in the first consecutive 3,000 patients. The ELCA Investigators.

OBJECTIVES: We report the comprehensive results of the first consecutive 3,000 patients treated in an excimer laser coronary angioplasty registry. BACKGROUND: Excimer laser coronary angioplasty involves the use of a pulsed, 308-nm ultraviolet laser transmitted by optical fibers to reduce coronary stenoses. Preliminary reports have described safety and efficacy profiles in small numbers of patients. METHODS: Patients were enrolled in a prospective, nonrandomized manner. The catheters used were 1.3, 1.6, 2.0, 2.2 and 2.4 mm in diameter, at energy densities up to 70 mJ/mm2. Procedures were performed by standard angioplasty technique with conventional guide catheters. RESULTS: Seventy-five percent of patients were male, 68% were in Canadian Cardiovascular Society functional class III or IV and the cohort included 3,592 lesions. Procedural success (final stenosis < or = 50% without in-hospital Q wave myocardial infarction, coronary artery bypass surgery or death) was 90% and did not differ between the first 2,000 and the last 1,000 patients treated. There was no significant difference in success or complication rates with respect to lesion length, nor were there differences between selected complex and simple lesions. Complications included in-hospital bypass surgery (3.8%), Q wave myocardial infarction (2.1%) and death (0.5%). Coronary artery perforation occurred in 1.2% of patients (1% of lesions) but significantly decreased to 0.4% in the last 1,000 patients (0.3% of lesions). Angiographic dissection occurred in 13% of lesions, transient occlusion in 3.4% and sustained occlusion in 3.1%. Comprehensive lesion morphologic data collected in the latter portion of the study showed the procedure predominantly limited to American College of Cardiology-American Heart Association type B2 and C lesions, with no significant difference in short-term outcome between groups. CONCLUSIONS: Excimer laser angioplasty can be safely and effectively applied, even in a variety of complex lesions not well suited for percutaneous transluminal coronary angioplasty. These types may include aorto-ostial, long lesions, total occlusions crossable with a wire, diffuse disease and vein grafts. Most recent data show a trend for the selection of predominantly complex lesions and a reduction in the incidence of perforation. This procedure may broaden the therapeutic window for the interventional treatment of selected complex coronary artery disease.

Angioplasty, Balloon, Coronary↗
PubMed1994

Venous reflux in patients with previous deep venous thrombosis: correlation with ulceration and other symptoms.

PURPOSE: Deep vein thrombosis (DVT) in many cases leads to chronic symptoms in the damaged leg, even though the affected veins have recanalized. The major hemodynamic defect in such recanalized veins is reflux. The incidence and extent of reflux has been studied in patients with proven DVT and correlated with concurrent symptoms. METHODS: Two hundred seventeen limbs in 183 patients were examined by duplex scanning from January 1989 to October 1992. All limbs had previous DVT diagnosed by venography. Sites and extent (proximal, distal, or both) of reflux were identified by meticulous duplex scanning of the whole venous system and correlated with presenting symptoms. RESULTS: The patients were classified into nine groups on the basis of the classification of the system involved (superficial, deep, or superficial and deep) and whether the reflux was found proximal or distal to the knee or both. Eight-one limbs belong to chronic venous insufficiency class 1, 92 belong to class 2, and 38 belong to class 3. Reflux was confined to the deep venous system in 84 limbs (38.7%), to the superficial system in 31 (14.3%) limbs, and to both systems in 102 (47%) limbs. It was confined to proximal veins only in 48 (22.1%) limbs, distal only in 56 (25.8%) limbs and throughout the limb in 113 (52.1%) limbs. The incidence of swelling was increased by distal or a combination of proximal and distal reflux regardless of which system was involved. In limbs with superficial venous insufficiency (SVI) or deep venous insufficiency (DVI) only, the incidence of skin changes was not affected by the extent of reflux. However, in limbs with combined SVI and DVI, it was increased in the presence of reflux throughout the limb. Absence of distal reflux was associated with a low incidence of skin changes even in the presence of DVI. Ulceration increased with an increased extent of reflux in the presence of SVI. Absence of superficial reflux was associated with a low incidence, even in the presence of DVI. CONCLUSIONS: The data suggest that as far as the skin changes and ulceration are concerned, distal reflux and reflux in the superficial veins are more harmful than reflux confined to the deep veins, even when such reflux extends throughout the deep venous system.

Adolescent↗
PubMed1994

Superficial venous insufficiency: correlation of anatomic extent of reflux with clinical symptoms and signs.

PURPOSE: The aim of this study was to assess the distribution and extent of valvular incompetence in patients with reflux confined to the superficial venous system and correlate the extent of such reflux with clinical symptoms and signs. METHODS: Two hundred fifty-five limbs of 217 patients with superficial venous insufficiency and normal perforating and deep veins were examined with color-flow duplex imaging. One hundred twenty-three limbs (48.2%) of 102 patients had reflux confined to the long saphenous system, 83 limbs (32.6%) of 72 patients had reflux confined to the the short saphenous system, and 49 limbs (19.2%) of 43 patients had reflux in both long and short saphenous systems. RESULTS: In the long saphenous system the commonest pattern of reflux was that which extended throughout the length of long saphenous vein (LSV) (47%). Ache, swelling, and skin changes were common in the presence of below knee reflux irrespective whether the thigh segment was involved. Ulceration (8%) was found only in limbs with reflux extending throughout the length of LSV. In the short saphenous system the most common pattern of reflux extended throughout the length of short saphenous vein (SSV) (57%) without involvement of Giacomini or gastrocnemial veins. Ache and swelling were present in 62% and 72% of the limbs, but this incidence was not related to the extent of reflux. Swelling, skin changes, and ulceration occurred only when the whole of the SSV was involved. In the limbs with reflux in both the long and short saphenous systems, the most common pattern of reflux extended throughout the length of both systems (45%). In these limbs the incidence of swelling was 80%. The incidence of skin changes went from 44% when the below-knee segment of the LSV was involved to 73% when reflux occurred throughout the LSV and SSV. Ulceration (14%) was found only in the latter situation. Variable patterns of saphenogastrocnemial termination were seen. In 57.8% of the limbs SSV joined the popliteal vein just above the popliteal crease, whereas the SSV terminated in the thigh in 26.6%. CONCLUSIONS: We conclude that ache, ankle edema, and skin changes in limbs with reflux confined to the superficial venous system are predominantly associated with reflux in the below-knee veins. Ulceration is found only when the whole of the LSV is involved (8%) or when reflux is extensive in both LSV and SSV (14%).

Adolescent↗
PubMed1994

Bone density and turnover in Addison's disease: effect of glucocorticoid treatment.

Osteoporosis is a well-known side-effect of chronic treatment with glucocorticoids. We have studied vertebral bone mineral density (BMD) and biochemical markers of bone metabolism in 30 patients diagnosed of Addison's disease (AD) to determine the effect of long-term replacement treatment with hydrocortisone (30 mg/day) or prednisone (7.5 mg/day). Lumbar bone mineral density was measured with dual energy X-ray absorptiometry in L-1-4 in two occasions, separated by 12 months. BMD in premenopausal women and men with AD was similar to healthy controls and postmenopausal women had slightly lower results. Rate of change of bone density followed up over a period of 12 months was -0.82%. Bone loss was not influenced by duration or type of steroid treatment. Biochemical parameters, serum calcium, alkaline phosphatase, osteocalcin, procollagen type I, PTH and 25(OH)vitamin D were within normal limits. Our results show that in patients with AD, after replacement with low doses of glucocorticoids there is no significative trabecular bone loss neither modifications in bone formation markers.

Absorptiometry, Photon↗
PubMed1994

Absence of high anion gap metabolic acidosis in severe ethylene glycol poisoning: a potential effect of simultaneous lithium carbonate ingestion.

Ethylene glycol poisoning is accompanied by a high anion gap metabolic acidosis. We describe a case of severe ethylene glycol poisoning in which severe acidosis was not present. This appears to be due to a beneficial effect exerted by simultaneous ingestion of 80 lithium carbonate tablets, each containing approximately 4 mEq carbonate, with a potential bicarbonate load of 320 mEq. We postulate a protective effect of lithium carbonate due to the bicarbonate generated by this substance.

Acid-Base Equilibrium↗
PubMed1994

The effect of hydroxyethylrutosides on capillary filtration in moderate venous hypertension: a double blind study.

The aim of this study was to evaluate the effect of hydroxyethylrutosides on capillary filtration in subjects with mild to moderate venous incompetence--superficial varicose veins and/or deep venous disease and ankle oedema--using the vacuum suction chamber (VSC) device applied to the internal perimalleolar region and the wheal vanishing (WV) time. Subjects entered in to the study were randomised to receive either hydroxyethylrutosides (1 g twice daily for 4 weeks) or placebo for four weeks. The two groups entering and completing the study were comparable. Microcirculatory parameters (laser-Doppler resting flux, the venoarteriolar response, transcutaneous PO2 and PCO2) remained constant during the four week study in both groups. The WV time, which was comparable in the two groups at the beginning of the study decreased significantly [from a median 55 min (interquartile 955 min), to a median 45 minutes (interquartile 65-40 min) in the treated group, p < 0.01]. No change was observed in the WV time in the placebo group. Subjective symptoms measured with an analogue scale improved following treatment with hydroxyethylrutosides [foot oedema (p < 0.005), ankle oedema (p < 0.001), and paraesthesia (p < 0.01)]; only night cramps were reported less in patients receiving the placebo (p < 0.05). In conclusion, the WV time can be used to assess the beneficial effect of therapy on capillary filtration in subjects with mild-moderate venous hypertension, even after a short period of treatment, and before other microcirculatory parameters change. Furthermore, the changes observed in WV time correlate well with an improvement in patients symptoms.

Ankle↗
PubMed1994

Acute and long-term effect of elastic stockings in patients with varicose veins.

The acute and long-term effect of elastic stockings has been evaluated in 20 patients (20 limbs) with grade 2 venous disease. The sites of venous reflux were determined with colour flow duplex scanning. Air Plethysmography was used to measure the amount of venous reflux and the ejecting capacity of the calf muscle pump. The patients were classified in to two different groups, A and B. Both groups of patients wore elastic stockings for four weeks. In group A (no. = 9) the measurements were done before, during and one day after the removal of the stockings, whereas in group B (no. = 11) the last measurements were done immediately after the removal of the stockings. Patients that showed improvement in their haemodynamics were re-examined a week later. Elastic compression appeared to be beneficial in both groups. The application of the elastic stockings improved reflux and the residual volume fraction in both groups and the ejecting capacity of the calf muscle pump in group B. Immediately after the removal of the stockings (Group B) all the measurements regressed to the initial values with the exemption of the residual volume fraction. However, one week later, the latter also regressed to the original value. It is concluded that the beneficial effect of elastic stockings on the venous haemodynamics is present mainly when the stockings are worn. It is completely abolished within a day after their removal.

Bandages↗
PubMed1994

Risk factors associated with recurrent carotid stenosis.

The incidence of restenosis following carotid endarterectomy reported with duplex scanning has ranged from 6-19%. The aim of this study was to determine the importance of risk factors in the development of carotid stenosis following carotid endarterectomy. Two hundred-thirty patients who underwent carotid endarterectomy (nineteen bilateral carotid endarterectomies) and had complete follow-up with duplex scanning for at least one year have been studied between February 1983 and April 1989. Forty six patients developed restenosis (18.5% of carotid endarterectomies) whereas 184 patients did not restenose. All patients were studied for the following risk factors: age, sex, ischemic heart disease, smoking habit, family history of cardiovascular disease diabetes mellitus, hyperlipidemia and peripheral vascular disease. The incidence of ischemic heart disease, a positive family history of cardiovascular disease, hyperlipidemia and diabetes mellitus was significantly increased (p < 0.05) in patients with recurrent carotid stenosis (80.4%, 71.7%, 58.7%, 32.6% respectively) as compared to patients without a recurrent stenosis (55.7%, 33.5%, 31%, 10.5%). None of the above significant risk factors was strongly associated with early (< 2 years) carotid restenosis. There is an increased prevalence of clinical atherosclerotic risk factors such as family history of cardiovascular disease, diabetes mellitus, ischemic heart disease and hyperlipidemia in patients who develop carotid restenosis.

Aged↗
PubMed1994

Feasibility of on-line transesophageal echocardiography during balloon mitral valvulotomy: experience with 93 patients.

Percutaneous balloon mitral valvulotomy (PBMV) has become an established method of treating symptomatic patients with rheumatic mitral stenosis. PBMV is performed with fluoroscopic guidance alone in most centres. However, even experienced operators can be misled by radiographic anatomic landmarks. Transesophageal echocardiography (TEE) provides high-quality images of the atrial septum, left atrium, mitral valve, and surrounding structures and has a number of unique advantages that make it a useful adjunct to fluoroscopy for guidance and monitoring of patients during PBMV. The aim of this study was to demonstrate the feasibility, safety, and utility of on-line TEE during PBMV on awake patients. TEE was performed on 93 consciously sedated, awake patients in the cardiac catheterisation laboratory during PBMV. Ninety five patients were successfully intubated in the supine position. Two patients were excluded from PBMV based on mobile thrombi near the mouth of the left atrial appendage. The TEE was well-tolerated in the 93 patients who underwent PBMV, and no complications of TEE were detected. Major complications of PBMV were detected in 7 patients (severe MR, n = 3; tamponade, n = 1; large ASD, n = 3). We conclude that on-line TEE during PBMV is feasible, safe, and well tolerated. TEE-guidance facilitates transseptal catheterization and proper positioning of balloon catheters across the mitral orifice. TEE can help monitor the adequacy of PBMV and help decide whether or not subsequent dilatations are necessary. TEE can rapidly detect complications and thereby guide appropriate management of these complications.

Adolescent↗
PubMed1994

Bone loss and turnover in patients with liver transplantation.

We have studied bone turnover markers and bone mineral density (BMD) in 82 patients (26 females and 56 males) that underwent orthotopic liver transplantation in our center. Follow-up was for a median of 19.2 months (range 1-60 months). During this period they were treated with prednisone, azathioprine and cyclosporine in accordance with protocols. Spinal bone loss was measured with a dual energy X-ray densitometer (precision 1.3%), and, depending on Z score and BMD values, two groups were distinguished: A) Without osteoporosis: 47 patients, Z = -0.98 +/- 0.09 and BMD 0.899 +/- 0.098 g/cm2, and B) With osteoporosis: 35 patients, Z = -2.71 +/- 0.55 and BMD 0.739 +/- 0.080 g/cm2 (X +/- SD). Serum bone markers such as osteocalcin (BGP) 10.0 +/- 0.8 ng/ml and procollagen-I (pColl-I) 268.1 +/- 32.1 micrograms/ml, were found to be increased. Serum PTH was within the normal range. No significant differences were found between the etiologic subgroups studied with respect to bone loss. Also, no correlation was found between bone loss and duration of follow-up or other factors, such as immunosuppressant drugs or acute rejection. Our study confirms an increased prevalence of bone loss in patients with liver transplantation, which is associated with a high bone turnover, indicating that earlier diagnosis and treatment is necessary to improve survival and quality of life in these patients.

Absorptiometry, Photon↗