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Y Cottin

Publications and source records attributed to Y Cottin.

At least 91 records · Page 5Linked to original sources
PubMed1995

Magnetic resonance relaxation times in ventricular hypertrophy induced by myocardial infarction in the rat.

The purpose of this study was to evaluate changes in the proton nuclear magnetic resonance relaxation times (T1 and T2) after chronic infarction in the rat. Ligation of the left coronary artery was followed by various degrees of reduction in myocardial blood flow. The ligation induced infarction in the left ventricle and compensatory hypertrophy in the right ventricle, as evaluated by the ratio of right ventricle to body weight. The interventricular septum and the right ventricle did not become ischemic in this model and served as control areas. In the infarcted left ventricle our results showed an increase in the T1 and T2 relaxation times after 15 and 30 days of ligation and a slight decrease after 60 days. A similar change in the T1 values was observed in the right ventricle. In contrast, a persistent increase in the T2 relaxation times was observed in the right ventricle and correlated with the ratio of right ventricle to body weight (r = 0.54, p < 0.01). The observation that the magnetic resonance relaxation times in vitro are modified in the hypertrophic right ventricle after myocardial infarction could be important in interpreting magnetic resonance imaging in vivo. There was no relation between the changes in the relaxation times and the degree of myocardial ischemia.

Animals↗
PubMed1994

Early incidence of adriamycin treatment on cardiac parameters in the rat.

To evaluate the early effect of low doses of adriamycin (ADR) on cardiac parameters, male Wistar rats were injected with ADR (1 mg.kg-1.day-1) or saline for 10 days. Seven days later, T1 and T2 relaxation times were determined in left ventricular (LV) free wall, septum, and thigh muscle samples. In another experiment, performed on isolated working hearts of rats pretreated with ADR, LV performance was determined along with an index of myocardial lipid peroxidation in this tissue. Lipid peroxidation was enhanced (p < 0.05). This change was not associated with a reduced LV performance, since both aortic and cardiac flows measured in working heart preparations were similar between control and treated rats. However, the coronary flow was significantly reduced (control group, 21 +/- 1 mL.min-1.g-1, ADR group, 15 +/- 1 mL.min-1.g-1; p < 0.001). T1 increased in the LV free wall (665 +/- 3 to 696 +/- 5 ms, p < 0.001) and in the septum (657 +/- 3 to 696 +/- 5 ms, p < 0.01), while T2 increased only in the LV free wall (50.8 +/- 0.9 to 53.1 +/- 0.6 ms, p < 0.05). Myocardial water content was also significantly increased. No modification was observed in the thigh muscle samples. Thus, modifications of T1 and T2 relaxation times following ADR treatment are associated with biochemical changes implicating lipid peroxidation. These changes in relaxation times appeared earlier than hemodynamic deterioration and could provide a basis for the application of proton nuclear magnetic resonance imaging in the early detection of cardiac ADR toxicity.

Animals↗
PubMed1994

[Effect of rehabilitation after myocardial infarction on muscular metabolism. Contribution of phosphorus 31 NMR spectroscopy].

P 31 NMR spectroscopy is a recent technique which allows a non-invasive and direct analysis of oxidative metabolism and pH changes, an indicator of acidosis due to lactic acid accumulation in the skeletal muscles. The authors investigated oxidative muscular metabolism of the sural triceps in 10 patients after myocardial infarction by performing a study after the acute phase and repeating the study after a programme of physical training. At rest, there were no significant differences. On the other hand, for the same level of maximal effort, the depletion in phosphocreatinine (PCr) and the accumulation of inorganic phosphate (Pi) were significantly lower after physical training: the PCr/PCr + Pi increased from 0.467 +/- 0.179 to 0.538 +/- 0.20 (p < 0.02) and the Pi/PCr ratio decreased from 1.570 +/- 1.440 to 1.181 +/- 1.069 (p < 0.05). The pH at the same level of maximal exercise did not change significantly between the two periods: 6.85 +/- 0.16 vs 6.88 +/- 0.15 (NS). The peak oxygen consumption (VO2) measured during bicycle ergometry increased significantly from 23.4 +/- 10.5 to 28.3 +/- 12.14 ml/min/kg after exercise training (p < 0.01). In addition, a correlation was observed between the improvement of the peripheral parameters (PCr/PCr + Pi) and the increase in VO2 max (r = 0.757, p < 0.01). The authors results confirm the effects of physical training on oxidative metabolisms of the peripheral muscles and its influence on improvement of global performance of coronary patients.

Adult↗
PubMed1994

[Angiosarcoma of the pericardium. Apropos of a case].

Malignant primary cardio-pericardial tumours are rare and difficult to diagnose because of the diversity of their clinical expression. The authors report a case of pericardial angiosarcoma and review the literature, underlining the value of new non-invasive imaging techniques in the diagnosis and surgical approach to obtaining histological confirmation. Magnetic resonance imaging is a valuable tool in this context as it allows scanning of the tumoral extension in all spatial planes and the visualisation of the haemorrhagic signs of malignancy the pericardial effusion related to this pathology.

Heart Neoplasms↗
PubMed1994

[Lipomatous septal hypertrophy. Apropos of 3 cases].

Lipomatous hypertrophy of the inter-atrial septum is characterised by fatty accumulation in the inter-atrial septum. Long unrecognised, it has been discovered anew by virtue of the use of transesophageal echocardiography. The authors report three cases, including one presenting as acute ischemia of the right lower limb. After studying the contribution of imaging techniques to its diagnosis, the authors consider the principal differential diagnoses of this condition.

Aged↗
PubMed1994

[Uncommon cardiac manifestations disclosing pheochromocytoma. Apropos of 3 cases].

The diagnosis of pheochromocytoma is usually considered in the presence of permanent hypertension with exacerbations. However, pheochromocytoma may be responsible for a varied range of adrenergic symptomatology and hemodynamic equilibrium may be threatened by the spontaneous or induced massive release of pressor amines. Three cases form the basis of a description of unusual situations: acute pulmonary edema, acute circulatory failure and myocardial infarction with normal coronary vessels. The divercity and severity of these clinical situations are such that the possibility should always be suspected when confronted by any cardiomyopathy without obvious etiology, in particular in a hypertensive patient. The only treatment remains ablation of the tumour and diagnosis as an emergency is based, apart from history, on ultrasonography and/or abdominal CT scan and assay of urinary catecholamine derivative levels, which can be obtained within a few hours.

Adrenal Gland Neoplasms↗
PubMed1993

[Myocardial ischemia caused by the injection of dipyridamole followed by low level exertion on an exercise bicycle].

The purpose of this study was the feasibility, safety and analysis of the ischemic nature of the association of an injection of dipyridamole and an exercise test at low level exertion on an exercise bicycle for 4 minutes. The ischemic nature of this combination was assessed on the basis of three criteria: the onset of angina-type pain, electrical changes and scintigraphic abnormalities. The test could be carried out by all patients and the most common adverse events were headache (6.5%) and heartburn (3.5%). The 17 patients in this study who had one or more stenoses in excess of 70% presented with angina-type pain (3/17); electrical abnormalities (9/17) and scintigraphic abnormalities in all cases. Of the six patients who had lesions between 50 and 70%, 1 presented with angina symptoms, 2 with electrical abnormalities and 5 with scintigraphic abnormalities. Seven patients in this study showed no significant lesions when subjected to coronary artery angiography. However, angina-type pain and electrical signs were observed in 2 cases and one false positive result by scintigraphy. This study shows that it is possible to combine the injection of dipyridamole with an exercise test involving a low level of exertion on an exercise bicycle which gives a good diagnostic value to the CT scan. The frequency of clinical and electrical signs of ischemia makes it necessary to take the same precautions as for a peak exercise test.

Aged↗
PubMed1993

[Spontaneous coronary dissection. Apropos of 2 cases].

Spontaneous coronary dissection is a rare and still poorly understood pathological disease entity; the authors report two cases in which the diagnosis was reached in the context of incipient necrosis in young patients. A review of the literature reveals the main characteristics of this problem: the clinical aspect is generally that of acute coronary failure with the constitution of an infarction. The subjects are young with no risk factor but some cases of combination with a disease affecting the elastic tissue have been described. Female gender and the post-partum phase are promoting factors. Diagnosis was long established by means of autopsy but can now be based on coronary angiography. Histologically, the lesion is a hematoma which dissects the arterial wall between the internal two thirds and external third of the media. The main etiological hypothesis is acquired or congenital fragility of the media, which promotes the formation of a dissecting hematoma, however the triggering phenomenon remains poorly understood.

Adult↗
PubMedDate not supplied

Modulation of protein expression and activity by radiation: relevance to intracoronary radiation for the prevention of restenosis.

Restenosis is a common complication of percutaneous transluminal coronary angioplasty. Recent studies have demonstrated a striking reduction in the neointimal hyperplasia characteristic of restenosis following intracoronary radiation (IR), but the mechanisms by which radiation reduces neointima formation following balloon overstretch injury are not elucidated fully. In addition to direct antimitotic effects mediated via oxygen free radicals, ionizing radiation can induce the expression of numerous genes and thereby mediate indirect effects. Additionally, IR prevents restenosis at the cost of decreased healing and increased thrombosis, and we suggest that these adverse reactions can be modulated by adjunct pharmacology or gene-based strategies. This review discusses several genes and proteins modulated by radiation in the context of arterial injury, and their possible therapeutic relevance.

Animals↗
PubMedDate not supplied

Differential remodeling after balloon overstretch injury and either beta- or gamma-intracoronary radiation of porcine coronary arteries.

BACKGROUND: Restenosis is a consequence of both neointimal hyperplasia and vessel remodeling. Prior studies have shown that intracoronary radiation (IR) prevents neointima accumulation, but its contribution to vessel remodeling is unknown. The purpose of this study was to evaluate the effect of IR on differential vascular remodeling after balloon angioplasty in porcine coronary arteries. METHODS: A total of 20 juvenile swine (30 coronary arteries) were subjected to overstretch balloon injury (BI) followed by IR with either beta- or gamma-radiation ((90)Y or (192)Ir). After 2 weeks following treatment, serial tissue sections were perfusion fixed and stained by hematoxylin and eosin (H&E), Verhoeff von Giesson (VVG), or Masson Trichrome. Adventitial area (AA), lumen area (LA), vessel area (VA), intimal area (IA), and IA corrected for medial fracture length (IA/FL) were quantified by digital image analysis. The vessel circumference was divided into two regions containing (1) the undisrupted region (UReg) with the undisrupted arc of media and internal elastic lamina (IEL) and (2) the disrupted region (DReg) with the disrupted arc between the medial tears. Quantitative regional analysis was performed by (1) measuring the IEL to define the UReg, (2) calculating the area of the UReg with the perimeter value derived from measurement of the IEL, and (3) calculating the DReg as follows: LA+IA-UReg. Immunohistochemical smooth muscle cell alpha-actin and Masson Trichrome were quantified by digital image analysis. RESULTS: The IA/FL was significantly smaller following treatment with (90)Y or (192)Ir vs. control (P<.01). A smaller AA was obtained following IR with both beta- and gamma-sources vs. control (P<.01). The UReg calculation was smaller in the irradiated arteries as compared to control (beta: 2.3+/-0.4 mm(2), gamma: 2.1+/-0.5 mm(2), P<.01 vs. control; control: 3.6+/-0.7 mm(2)). In contrast, the DReg was increased following IR, as demonstrated by the FL and the calculated area of the injured segment (control: 2.7+/-0.5 mm(2); beta: 5.5+/-1.1 mm(2), gamma: 5.5+/-1.1 mm(2), P<.01 vs. control). Adventitial alpha-actin positive cell density (CD) was decreased after IR; however, the collagen density was similar. In contrast, the neointimal collagen density in the injured segment was significantly decreased following IR. CONCLUSION: We consider that the global arterial remodeling after IR is a heterogeneous process that includes the absence of retraction in an UReg and a positive remodeling in the DReg as shown in the porcine coronary model. These changes in adventitia and neointima appear to contribute to differential vascular remodeling caused by IR in injured vessels.

Angioplasty, Balloon, Coronary↗
PubMedDate not supplied

Intravascular radiation accelerates atherosclerotic lesion formation of hypercholesteremic rabbits.

OBJECTIVES: The purpose of the present study is to evaluate the effect of intravascular radiation (IR) on the arterial wall of uninjured vessels in the hypercholesteremic rabbit model. METHODS: Aortas of 24 New Zealand white rabbits were treated with either intravascular 192-Ir gamma-radiation (15 Gy at 2 mm from the center of the source) or were exposed to the source catheter without radiation (sham controls). Following the radiation treatment, the animals were fed a 2% cholesterol diet until euthanasia at 2 (n=8) or 6 (n=16) weeks. Arteries were analyzed using light and scanning electron microscopy (SEM); transforming growth factor beta (TGF-beta) 1, a promoter of connective tissue deposition, was also monitored. RESULTS: At 2 weeks, SEM analysis showed well-aligned endothelial cells in nonradiated segments, whereas irradiated arteries consistently contained adherent and subendothelial macrophages with focal areas of endothelial disruption. Further radiated segments at 2 weeks showed a 7-fold increase in active TGF beta-1 over nonradiated segments. At 6 weeks, there was a significant increase in plaque and vessel wall area relative to control arteries, however, no differences were noted in the density of actin-positive smooth muscle cells (SMCs) or macrophages. Similarly, no differences were noted in cell proliferation between groups as evidenced by the marker bromodeoxyuridine (BrdU). In contrast, nonirradiated segments frequently contained cellular areas with extracellular lipid. CONCLUSION: Exposure of previously uninjured vessels to IR and hypercholesterolemia is associated with increased plaque burden and leads to more advanced plaque types. Special care should be taken to minimize radiation exposure in normal vascular segments in hypercholesterolemic patients undergoing radiation therapy.

Animals↗
PubMedDate not supplied

Relationship between increased peak oxygen uptake and modifications in skeletal muscle metabolism following rehabilitation after myocardial infarction.

PURPOSE: Rehabilitation after myocardial infarction produces an increased peak oxygen uptake (VO2peak). This study investigates the relationship between the modifications in skeletal muscle metabolism and the modification in VO2peak induced by a standard program of physical training following a myocardial infarction. METHODS: Seventeen patients (14 male, 3 female) were studied by phosphorus 31(31P) magnetic resonance spectroscopy after the acute phase of a myocardial infarction and after 2 months of rehabilitation. Changes in calf muscle pH, phosphocreatine, and inorganic phosphates were measured at rest and during a plantar flexion-type incremental workload protocol. Calf muscle pH, phosphocreatine/(phosphocreatine + inorganic phosphates), and inorganic phosphates/phosphocreatine ratios were compared at the highest identical workload attained in both studies. The VO2peak (mL/kg/min) was determined during a cycle stress test. RESULTS: At the highest identical workload attained in both tests, the ratio phosphocreatine/(phosphocreatine + inorganic phosphates) was significantly higher (0.48 +/- 0.15 to 0.57 +/- 0.18: P < .001), and the ratio inorganic phosphates/phosphocreatine was lower (1.38 +/- 1.14 to 0.99 +/- 0.87: P < .01). After rehabilitation, no difference was observed for the pH at stress (6.83 +/- 0.16 to 6.91 +/- 0.14: not significant [NS]). The increase in the VO2peak was significant after rehabilitation (24 +/- 9 to 29 +/- 11 mL/kg/min: P < .001). The VO2peak improvement induced by the physical training was correlated with the increase in the phosphocreatine/(phosphocreatine + inorganic phosphates) (r = 0.818, P < .001). CONCLUSIONS: The reduction in phosphocreatine depletion indicated that the oxidative capacity of the skeletal muscle was improved during the rehabilitation. The good correlation between the indexes of skeletal muscle metabolism and VO2peak suggests the peripheral effect of training.

Adaptation, Physiological↗
PubMedDate not supplied

Muscle metabolism assessed by phosphorus-31 nuclear magnetic resonance spectroscopy after myocardial infarction in rehabilitated patients: a 1-year follow-up.

BACKGROUND: The most common effect of postmyocardial infarction (post MI) rehabilitation is an increase of peak maximal oxygen consumption correlated with changes in calf muscle metabolism, but there are few data on follow-up after rehabilitation on skeletal muscle and maximal oxygen consumption. The purpose of this study was to investigate the respective modifications in skeletal muscle metabolism and peak oxygen consumption (VO2) occurring during a supervised rehabilitation program and 1 year after MI in patients free of heart failure. METHODS: Fifteen outpatients were studied prospectively after the acute phase of the MI, at the end of the rehabilitation program (2 months after the MI), and 1 year after. The rehabilitation comprised 20 sessions with three sessions per week. The program consisted of exercise training with bicycle, arm ergometer, and treadmill. The program also included respiratory exercises, psychological support, and counseling for secondary prevention of cardiovascular diseases. At each visit, a stress test on a bicycle ergometer was performed and the peak VO2 was measured. Phosphorus magnetic resonance spectroscopy of the gastrocnemius muscle was performed at rest and during a plantar flexion-type exercise against an adjustable load. Data were analyzed using analysis of variance and post-hoc test when appropriate. RESULTS: The mechanical power output measured during the bicycle exercise increased from 111 +/- 28 watts at the post MI test to 136 +/- 40 watts after rehabilitation (post rehab) and decreased to 125 +/- 36 watts at 1 year. The peak VO2 increased significantly (P < 0.05) from 22 +/- 7 ml/kg-1/min-1 (post MI) to 27 +/- 9 ml/kg-1/min-1 (post rehab), and decreased significantly to 24 +/- 8 ml/kg-1/min-1 (1 year). The mechanical power output measured in the magnet during the stress test increased from 2.22 +/- 0.13 watts (post MI) to 2.85 +/- 1.24 (post rehab), and stabilized at 2.78 +/- 1.10 watts at 1 year. At the highest workload attained in the three successive tests, the phosphocreatine/(phosphocreatine + inorganic phosphate) ratio rose significantly (P < 0.05) from 0.46 +/- 0.13 (post MI) to 0.51 +/- 0.13 (post rehab) and remained at 0.51 +/- 0.13 at 1 year. CONCLUSION: The improvement of the peak VO2 after training post MI is not maintained 1 year later. This decline is not accompanied by muscular metabolic abnormalities. This suggests that the muscle metabolism after MI remains normal, and that the long-term decrease of the peak VO2 reflects a global deconditioning that should be avoided by maintaining a long-term phase III rehabilitation program.

Adult↗