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Biomedical subjects

P Chevalier

Publications and source records attributed to P Chevalier.

At least 55 records · Page 3Linked to original sources
PubMed1997

Stimulatory effect of a specific substance P antagonist (RPR 100893) of the human NK1 receptor on the estradiol-induced LH and FSH surges in the ovariectomized cynomolgus monkey.

Utilizing a human NK1 receptor antagonist (RPR 100893), the present in vivo study was designed to test the hypothesis that endogenous substance P (SP) modulates the action of 17beta-estradiol in inducing luteinizing hormone (LH) and follicle stimulating hormone (FSH) surges in ovariectomized cynomolgus monkey. Plasma concentrations of LH and FSH as well as NK1 receptor antagonist and SP were measured during the development of the negative and positive feedback phases which follow a single administration of estradiol benzoate (50 microg/kg) to long-term ovariectomized monkeys. Daily administration by gastric intubation of 1 mg/kg or 10 mg/kg of the NK1 receptor antagonist (RPR 100893) leads to detectable levels of the antagonist in the blood of treated animals for at least 6 hr after its administration. These levels are in agreement with the experimentally determined IC50 value of the antagonist. The most striking finding of this study is that LH and FSH releases are enhanced during the descending arm of the estradiol benzoate-induced LH and FSH surges, which suggests that endogenous SP normally has an inhibitory role during this time. The enhancement of LH release is approximately 50%, regardless of the amount of the NK1 antagonist used. However, the enhanced FSH release is more important. Furthermore, blockade of the NK1 receptor with the smaller dose of the antagonist leads to a small, but significant, increase in plasma levels of SP, indicating that blockade of SP receptors leads to an increased release of SP. Collectively, these results further substantiate the link which exists between the ovarian steroid 17beta-estradiol and SP systems. Also, for the first time, these results demonstrate an inhibitory involvement of the human NK1 receptor in the 17beta-estradiol-induced pseudo-ovulatory gonadotropin surges in the ovariectomized monkey.

Animals↗
PubMed1997

Mechanical cardiac valve thrombosis in patients in critical hemodynamic compromise.

BACKGROUND: Valve obstruction is a life threatening complication of mechanical valve prosthesis. METHODS: From 1985 to 1993, 29 consecutive patients were hospitalized in our intensive care unit for mechanical prosthetic valve thrombosis (PVT). There were 12 men and 17 women aged 25-75 years (57 +/- 12). Prosthetic valve location was mitral in 14 patients, aortic in 6, aortic and mitral in 9. PVT occurred from 15 days to 174 months (67 +/- 52 months) after surgery. Delay from first symptoms to hospitalization ranged from 1 to 45 days (11 +/- 11). RESULTS: First clinical symptoms were progressive left heart failure in 17 patients, stroke in 6, and chest pain in 6. Furthermore, acute myocardial infarction was later documented in 3. Left heart failure NYHA III-IV was present in 26 patients (90%) on admission and 10 of those were in cardiogenic shock. Anticoagulation regimen was inadequate in 13 cases (45%). It has been recently stopped in 8 patients and incorrectly conducted in 5. Total hospital mortality was 41.3% (12). It was independent of type and position of the valve prosthesis. Diagnosis of PVT was only made at autopsy in 3 patients who died of recurrent myocardial infarction (2) or cardiogenic shock (1). Five further patients died before any surgery could be attempted (cardiac arrest: 2, cardiogenic shock: 3). Valve replacement could be done in 21 cases, 7 of whom were in cardiogenic shock and 9 had severe pulmonary edema. Four patients died after surgery, the operative mortality was 19%. CONCLUSION: PVT remains a serious complication of mechanical heart valve prostheses. Overall mortality rate is high, related to difficulty to diagnosis, delay to hospitalization and severe clinical condition at admission. In our study, operative risk remained acceptable even when the clinical presentation was severe.

Adult↗
PubMed1997

Hepatocellular adenomas in glycogen storage disease type I and III: a series of 43 patients and review of the literature.

BACKGROUND: Hepatocellular adenomas may develop in patients with glycogen storage disease types I and III, and the malignant degeneration of adenomas in hepatocellular carcinoma has been reported in ten cases. The aim of this work was to study the characteristics of hepatic adenomas in a large series of 43 patients with glycogen storage disease types I and III and to determine the optimal means of follow-up. METHODS: The charts of 43 patients with glycogen storage disease type I and III were studied. In all these patients, abdominal ultrasonography and the determination of serum alpha-fetoprotein had been performed yearly and serum concentrations of several proteins were determined once. RESULTS: 51.8% of patients with type I and 25% of patients with type III glycogen storage disease had hepatic adenomas at the time of the study. The male to female ratio was 2 to 1 in type I, and no female had adenomas in type III. No evidence of malignant transformation was observed during the follow-up period. Serum concentrations of several proteins were significantly higher in patients with hepatic adenomas than in patients without such lesions. CONCLUSIONS: In patients with glycogen storage disease type I and III, the determination of alpha-fetoprotein serum concentration has to be combined with yearly hepatic ultrasound examinations. Other investigations such as CT scan should be considered when the size of any adenoma increases. The malignant transformation of hepatocellular adenoma into hepatocellular carcinoma remains a rare event.

Adenoma, Liver Cell↗
PubMed1997

Clear cell sarcoma: an extremely rare cause of pleural disease.

We present the case of a 36 yr old woman with a persisting complaints of left chest pain. A chest radiograph revealed multiple left pleural thickenings. Classical exploration was negative. Thoracic surgery allowed the subtotal removal of a huge pleural tumour. The histological examination revealed a clear cell sarcoma. The literature on this extremely rare tumour is reviewed.

Adult↗
PubMed1997

Cardiac troponin I does not increase after cardioversion.

BACKGROUND: Serum total creatine kinase (total CK) level increases in the patients following electrical cardioversion. The same has been observed with CK-MB, an isoenzyme of the total CK with some cardiospecificity. Cardiac troponin I (cTnI), a new specific cardiac biological marker, is highly effective to discriminate myocardial and muscular injuries after noncardiac surgery. METHODS: To assess cardiac damage after cardioversion, we measured serum cTnI, myoglobin, total CK, CK-MB mass, 1, 2, 3, 4, 8, 12, and 24 h after elective cardioversion of supraventricular tachycardia in 28 patients (eight women, 20 men; mean age, 64 +/- 10 years). Cumulative energy was below 370 J in 17 patients, between 370 and 900 J in eight patients, and 1,020 J in three patients. Serum cTnI was measured using a sandwich immunoenzymologic assay. The detection limit of the assay was 0.35 microgram/L and normal values range from 0.35 to 1.3 micrograms/L. RESULTS: In all but three patients, cTnI remained below 0.35 microgram/L. In these three patients, cTnI ranged between 0.35 and 0.9 microgram/L. There was no correlation between cTnI and the number or the energy of cardioversion. Myoglobin and total CK increased to abnormal concentrations in 11 patients (myoglobin, 630 +/- 190 micrograms/L, and total CK, 2,584 +/- 780 U/L) and reached myocardial infarction-like values in five patients. Modest increases of CK-MB were then also observed. A strong correlation was observed between the total energy of direct current cardioversion and the increase of either myoglobin (r = 0.87; p < 001) or total CK (r = 0.81; p < 001). CONCLUSION: Cardioversion in a clinical setting does not induce elevation of cTnI. Increase in total CK, CK-MB, and myoglobin may be due solely to muscular lesions and is closely related to the cumulative energy delivered.

Aged↗
PubMed1997

Defibrillation threshold and electrode configurations: an experimental study testing three configurations in twelve pigs.

OBJECTIVE: The choice between epicardial or subcutaneous patches remains unclear and depends essentially on the team's habits. This study tested how much an additional patch can decrease defibrillation threshold (DFT), and compared a Subcutaneous Array and an epicardial patch. Today most implantable automatic defibrillators have a transvenous endocardial configuration alone but when the DFT remains high an additional patch is necessary. EXPERIMENTAL DESIGN: Three different configurations were tested with biphasic shocks in 12 pigs: Endovenous lead (Endo), Endovenous lead + subcutaneous patch (Endo + SQ) and Endovenous lead + epicardial patch (Endo + Epi). For each animal DFTs were determined in a balanced random order for the 3 configurations. Ventricular fibrillation was induced by pacing (30 Hz, 8 V, for 5 seconds). DFT was accurately measured with the up/down procedure until 3 reversal of defibrillation success or failure occurred. DFTs (mean +/- SD) were extracted and compared using paired t test and analysis of variance. RESULTS: DFTs were 14.6 +/- 11.0 J for Endo and significantly decreased (p < 0.01) when an additional SQ (9.4 +/- 7.2 J) or epicardial patch (8.9 +/- 6.5 J) was added to endovenous lead, without significant difference between Endo + SC and Endo + Epi configurations. CONCLUSIONS: Regarding this important decrease of DFT (respectively -35% for Endo + SC and -39% for Endo + Epi), additional patches should be more often recommended in patients with low safety margin of DFT. In those cases subcutaneous patches should be preferred instead of epicardial patches. Moreover, an additional reason to recommend this attitude could be the possible generator batteries saving.

Animals↗
PubMed1997

[Acute dissection of the thoracic aorta. Symptoms and complications].

Acute dissection of the aorta is an increasingly recognised pathology, the diagnosis of which is sometimes delayed despite the fact that advances in medical imaging provide almost perfect diagnostic accuracy. Some of the symptoms are particularly suggestive. Chest pain is the key symptom, and the greater the intensity, usually described as a migratory intrathoracic tearing sensation irradiating towards the lumbar region. The other symptoms become meaningful in association with this pain: paraplegia, acute peripheral ischaemia, hemiplegia. Clinical examination is capital when a diastolic murmur of aortic regurgitation is heard or when a distal pulse is absent, the blood pressure is asymmetric or a pericardial rub is detected. The frighteningly poor initial prognosis of acute dissection of the aorta has been transformed by surgery, providing, that it is performed early. Optimal therapeutic results can only be obtained by and early diagnosis.

Acute Disease↗
PubMed1996

[Pregnancy after organ transplantation].

In the past twenty years, the increased number of organ transplant recipients and better immunosuppressive regims have enhanced transplant survival, and several transplant recipients may conceive pregnancy or paternity after the graft. There is no French registry of posttransplant pregnancies, but analysis of the international literature reports 2300 pregnancies after kidney transplantation, 100 pregnancies after heart and 3 after heart-lung transplantation, 90 pregnancies after liver transplantation. Paternity after the graft may occur with no increased incidence of malformations, nor teratogenic and immunosuppressive effects due to the therapeutic regimen. All pregnancies after transplantation have to be considered at high risk, underlying the need for simultaneous follow-up by the gyneco-obstetrical team for the baby and the pregnancy and by the transplant team for the graft and the mother. Outcome is generally excellent for the mother and the baby. However, transplant recipients with either high blood pressure, diabetes, serum creatinine above 160 mumol/l or within less than 1 year after the graft should be considered at too high risk to conceive a pregnancy with no deleterious effect on the mother and/or on the foetus.

Embryonic and Fetal Development↗
PubMed1996

[Brucella pancarditis with fatal outcome].

Brucella endocarditis was diagnosed in a 21-year-old itinerant farm worker hospitalized for acute pulmonary edema. History taking revealed cough, fever and sweating one month earlier which had been treated with antibiotics. At admission, echography showed lesions on the aortic valve and hemocultures identified Brucella meltensis. On day 7 of specific treatment with doxycycline (200 mg/day) and rifamycine (1200 mg/day), and despite digitalics and diuretics, left ventricular failure rapidly worsened, leading to cardiac arrest and death before emergency surgery could be performed. Autopsy showed occlusive vegetations on the aortic valves facing the right coronary ostium, deep ulceration of the valsava sinus with abscess formation and fibrino-hemorragic pericarditis involving both the anterior and posterior walls of the epicardium. Gram negative germs were evidenced in the abscess alone. This case emphasizes the potentially rapid destructive effect of Brucella melitensis and confirms that surgery is the safest therapeutic alternative for aortic valve localizations. Surgery should be performed without delay.

Adult↗
PubMed1996

Stratification of time-frequency abnormalities in the signal-averaged high-resolution ECG in postinfarction patients with and without ventricular tachycardia and congenital long QT syndrome.

Having developed sound mathematical techniques that allow precise mapping of cardiac signals in the time-frequency (TF) and time-scale planes, the next important issue is to extract from these representations information that best reflects the electrophysiologic and anatomic derangement unique to patients at risk of arrhythmias and other cardiac diseases. In this study, the authors present a new method that stratifies the magnitude of the TF transforms of abnormal cardiac signals into distinguishing features by comparing the means of the coefficients of the TF transforms of any study population to the corresponding means of a control population using a standard ANOVA technique. This results in a three-dimensional mapping of the high-resolution ECG into time, frequency, and P value components. Significant energy increases are given positive P values and depressed energies are given negative P values: these are ranked according to a color scale. The method was tested on two study populations: postmyocardial infarction patients with documented ventricular tachycardia (MI+VT, n = 23) and without (MI-VT, n = 40) and patients with congenital long QT syndrome (LQTS, n = 19). Two groups of healthy control subjects (n = 31 and n = 40) were used as a reference group matched for sex. The study results were based on the Morlet analyzing wavelets, with frequencies ranging from 40 to 250 Hz in 10 logarithmically progressing scales, and computed millisecond per millisecond over a 350-ms analyzing time window, starting from 100 ms before the onset of the QRS. The patients with MI+VT displayed significantly increased high-frequency components in the 40-250-Hz frequency range, corresponding to prolonged QRS duration and late potentials in the area from 80 to 150 ms after QRS onset. Significantly depressed energy (P < 10(-4)) was also observed for the 40-106-Hz frequency range in the first 50 ms of the QRS complex, mainly in lead Y and in the magnitude vector. In patients with LQTS, significant modifications (P < 10(-2)) were observed in the first half of the QRS and in the ST-segment, in all leads, revealing anomalies in the genesis of the ventricular depolarization and repolarization processes. In conclusion, the authors propose a new method for the stratification of abnormal TF components occurring in the signal-averaged high-resolution electrocardiogram of patients at risk of VT and fibrillation under different pathologic conditions.

Adult↗
PubMed1996

Symptomatic pericardial disease associated with patch electrodes of the automatic implantable cardioverter defibrillator: an underestimated complication?

Constrictive pericarditis can be associated with ICD patch electrodes. During a mean follow-up of 24 months, in a population of 35 patients who received ICDs with a patch electrodes configuration, we identified three patients with clinical and hemodynamic signs compatible with this event. Patient 1, a 35-year-old male, underwent implantation of an ICD because of a primary electrical disease complicated by cardiac arrest. Fourteen months later he complained of exertional dyspnea without any signs of heart failure. Right heart catheterization showed high filling pressures and diastolic dip and plateau in pressure curves. Thoracotomy and pericardial exploration were performed. Three months after removal of the patches and insertion of an endocardial lead system, the patient had normal respiration. Patients 2 and 3, who suffered from coronary heart disease without heart failure, exhibited a hemodynamic profile suggestive of constrictive pericarditis: in one patient, 10 months after ICD implantation, associated with right heart failure; and in the other, 18 months after ICD implantation with left heart failure. Patch electrodes were removed in these two patients and replaced by endocardial lead electrodes with subsequent clinical improvement. It is concluded that constrictive pericarditis related to epicardial patch is not an uncommon occurrence during ICD therapy and should be considered in patients who show clinical signs of cardiac decompensation.

Adult↗
PubMed1996

Improved appraisal of the quality of life in patients with automatic implantable cardioverter defibrillator: a psychometric study.

BACKGROUND: Patients with an implanted cardioverter defibrillator (ICD) may experience a certain degree of suffering. A sample of 32 patients was surveyed to determine the psychological benefit resulting from this treatment. METHODS: Hamilton Anxiety Scale, Beck Depression Inventory and a shortened version of the Minnesota Multiphasic Personality Inventory were used. A 10-item scale and a global index of quality of life were especially designed to assess cardioverter defibrillator tolerance and the effect of its implantation on patients' current well-being. RESULTS: Both quality of life index scores were negatively correlated with anxiety and depression. Occurrence of shocks had no influence on psychological well-being. CONCLUSIONS: The questionnaires provided a simple and reliable measure of quality of life in ICD patients. Prior to implantation, technical explanations should be accompanied by stress management techniques adapted to the patients' psychological background.

Adaptation, Psychological↗
PubMed1996

Extensive brain calcifications, leukodystrophy, and formation of parenchymal cysts: a new progressive disorder due to diffuse cerebral microangiopathy.

A new cerebral disorder, described in three unrelated children, has recognizable clinical, radiologic, and neuropathologic findings. The onset occurs from early infancy to adolescence with slowing of cognitive performance, rare convulsive seizures, and a mixture of extrapyramidal, cerebellar, and pyramidal signs. CT shows progressive calcifications in the basal and cerebellar gray nuclei and the central white matter. MRI reveals diffuse abnormal signals of the white matter on T2-weighted sequences. A special feature is the development of parenchymal cysts in the cerebellum and the supratentorial compartment, leading to compressive complications and surgical considerations. Neuropathologic examination of surgically removed pericystic samples reveals angiomatous-like rearrangements of the microvessels, together with degenerative secondary changes of other cellular elements. Both the anatomic findings and the course of the disease suggest a constitutional, diffuse cerebral microangiopathy resulting in microcystic, then macrocystic, parenchymal degeneration.

Brain Diseases↗
PubMed1996

[Aneurysms of the left ventricle without atheromatous coronary artery disease. Apropos of 2 cases].

Left ventricular aneurysms are usually secondary to myocardial infarction with atheromatous coronary artery disease. The authors report two rare cases of non-atheromatous left ventricular apical aneurysms. The first case was clearly post-traumatic but the diagnosis in the second case was more difficult. The authors discuss the aetiological diagnosis of these rare non-atheromatous aneurysms in adults and the therapeutic management with respect to these two cases and a review of the literature.

Coronary Angiography↗
PubMed1996

[Predictive factors of induction of ventricular arrhythmia under amiodarone].

A good result of electrophysiological investigations under amiodarone therapy distinguishes a low risk group of patients with malignant ventricular arrhythmias. The authors set out to determine the factors predictive of this response in order to identify patients better protected by amiodarone at an earlier stage. Fourty-five patients with an average age of 56 years, were referred for evaluation of severe ventricular arrhythmias, monomorphic ventricular tachycardia being inducible during electrophysiological investigation in all cases before treatment. Amiodarone was prescribed orally at degressive doses. A control electrophysiological study was performed 4 to 6 weeks later. Eighteen patients (40%) were considered to be responders (absence of inducible ventricular arrhythmia or inducible non-sustained tachycardia or tachycardia with a cycle length increased by over 100 ms with respect to the base-line study). The other 27 patients were considered to be non-responders. No clinical or paraclinical parameter was found to distinguish responders from non-responders. The authors conclude that the data obtained before control electrophysiological investigation under amiodarone does not allow prediction of the response to this drug. The search for early prognosis of the efficacy of amiodarone in preventing ventricular arrhythmias therefore requires electrophysiological investigation after impregnation.

Adult↗