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Biomedical subjects

M Marchand

Publications and source records attributed to M Marchand.

At least 37 records · Page 2Linked to original sources
PubMed1997

[Treatment of congenital heart diseases with pulmonary artery cerclage. Immediate and medium term results in 51 patients].

The aim of this study was to assess the results of pulmonary artery banding in a retrospective study of 51 consecutive children treated from January 1980 to December 1993. The study population was 24 girls and 27 boys with an average age of 6.2 months, of average weight of 4.01 kg. The cardiac conditions treated were ventricular septal defects in 24 cases (isolated and associated with one or more cardiovascular malformations or multiple), complete atrioventricular canal in 12 cases (isolated or associated with several cardiovascular malformations), single ventricle in 7 cases, double outlet right ventricle in 3 cases, transposition of the great arteries with ventricular septal defect in 2 cases, tricuspid atresia in 2 cases, and a complex lesion with double discordance in one case. The average duration of banding was 2.35 years (n = 49). Hospital morality of banding was 1.9% (1/51). Late mortality was 14.8% (7/47). Twenty-one patients (42.8%) had complications of banding. The survival rates of children who underwent banding was 86.8% at 1 year and 80.6% at 11 years. The low hospital mortality leaves a role for pulmonary artery banding as a palliative procedure in congenital heart disease in which early correction is impossible or carries and unacceptable risk. Complications of banding justify attempts to improve the technique, by making adjustable bands.

Child↗
PubMed1997

[Intermediary results with the CarboMedics bileaflet valvular prosthesis].

From December 1988 to December 1995, 212 patients underwent valve replacement with a CarboMedics bileaflet valve in our institution (103 aortic valve replacements, 72 mitral valve replacements, and 37 double valve replacements). Fifty-five percent were male patients. Mean age was 53.8 +/- 12.7 years. Forty seven percent of patients were in NYHA clinical status III or IV. Operative mortality was 3.7% (8/212). All patients but eight were followed-up for an average of 2.9 years after their operation and total follow-up was 617 patient-years. At the time of the study, more than 90% of patients were in NYHA class I or II, 26% were in atrial fibrillation and 100% of patients received anticoagulation treatment. There were 15 late deaths. After 7 years, the actuarial survival rate was 84 +/- 7%. Three patients died of valve-related causes. Valve-related complications included 5 thromboembolic episodes (0.8% patient-year), 18 anticoagulant-related complications (2.9% patient-years), 3 endocarditis (0.5% patient-year), and 4 reoperations (0.6% patient-year). After 7 years, freedom from thrombo-embolic complication was 97 +/- 2%, from anticoagulant-related complications was 88 +/- 6%, from endocarditis was 96 +/- 4%, and from reoperation was 95 +/- 5%. We conclude that the 7-year results compare with other bileaflet valves. More follow-up and larger studies are mandated to give definite conclusions.

Actuarial Analysis↗
PubMed1997

[Echocardiographic Doppler study of left ventricular filling in the diagnosis of minimal or moderate rejection in cardiac transplantation].

The study of left ventricular filling by Doppler echocardiography may be a non-invasive diagnostic method of detection of acute rejection of cardiac transplants. The aim of this study was to assess the value of the method for diagnosis of minimal to moderate rejection (grades 1 to 3 of the Billingham classification). A total of 466 Doppler echocardiographic studies were performed in 23 cardiac transplantation patients (21 men, mean age 49.3 +/- 10 years) with endomyocardial biopsy as the reference method for the diagnosis of rejection. Over a follow-up period of 18.5 +/- 10 months, 22.7% of biopsies showed minimal or moderate rejection. The Doppler measurements of the isovolumic relaxation period and peak early diastolic (E) velocity with respect to the mitral velocity-time integral were no different in cases of acute rejection. The only difference observed was in the mitral half-pressure time which was much shorter in cases of rejection. However, after drawing a ROC graph, the accuracy of this parameter was insufficient for diagnosing rejection irrespective of the threshold of variation considered (23% sensitivity for a 20% shortening and 36% sensitivity for a 10% shortening). The authors conclude that Doppler echocardiographic study of left ventricular filling is of limited value for the diagnosis of acute minimal or moderate rejection in cardiac transplant patients. The half-pressure time may be a useful complement to endomyocardial biopsy or when biopsy investigations are performed less frequently.

Acute Disease↗
PubMed1996

Infrequent expression of the MAGE gene family in uveal melanomas.

It has previously been reported that MAGE-1, -2, -3 and -4 genes are expressed in human cancers including cutaneous melanoma. MAGE-1 and MAGE-3 represent targets for specific immunotherapy because they encode peptide antigens which are recognised by cytotoxic T lymphocytes (CTL) when presented by HLA class I molecules, and pilot clinical trials with these peptides are currently in progress. It is likely that other members of the MAGE gene family may also encode antigens recognised by CTL. Uveal melanomas, like cutaneous melanomas, arise from melanocytes that are derived from the neural crest. To determine if uveal melanoma patients would be suitable for MAGE-peptide immunotherapy, the expression of MAGE-1, -2, -3 and -4 genes was assessed by reverse transcription followed by polymerase chain reaction (RT-PCR) amplification and ethidium bromide staining. Expression of MAGE genes was not detected in any of 27 primary tumours. Either MAGE-1 or MAGE-4 was expressed in only 2 of 26 metastatic samples, but expression of MAGE-2 or -3 was not detected. Our data suggest that, unlike cutaneous melanomas, uveal melanomas may not be suitable candidates for MAGE-peptide immunotherapy.

Antigens, Neoplasm↗
PubMed1996

Computerized single-breath nitrogen washout: predicted values in a rural French community.

Comparative manual and computer measurements of the alveolar N2 slope and closing volumes have indicated systematic differences. When a computerized system is used in field surveys, predicted values are to be obtained under the same conditions. Therefore, we measured the alveolar nitrogen slope (phase III, PIII), closing volume (CV), and closing capacity (CC) from single-breath N2 washout maneuvers in 158 healthy subjects (68 females), ages 21 to 64 years, from a rural community living in a nonpolluted area of northeast France. PIII, the CV to vital capacity ratio (CV:VC, %), and the CC to the total lung capacity ratio (CC:TLC, %) were regressed against age, height, weight, and the body mass index (BMI, kg/m2) and prediction equations with 95% confidence intervals were computed. PIII increased with age in both sexes and tended to decrease with height in males (r = -0.19, p = .08). The CV:VC and CC:TLC ratios depended on age and, in males, increased with the BMI. Despite accepting a 15% difference between the test VC and the spirometric VC, only 46.3% of asymptomatic nonsmokers produced a valid single-breath nitrogen washout (SBN2) test. This high failure rate limits the usefulness of the test for epidemiologic purposes when older populations "naive" to pulmonary function testing are studied under field-survey conditions.

Adolescent↗
PubMed1996

Pericardial valves in small aortic annuli: ten years' results.

OBJECTIVE: The first generation of pericardial valves was withdrawn from the market because of too high a rate of premature failure. With an original design, the Carpentier-Edwards pericardial valve promised improved results, especially in small sizes. METHODS: Ninety patients who underwent an isolated aortic valve replacement with a 19 mm Carpentier-Edwards pericardial bioprosthesis in our institution between July 1984 and December 1993 were followed up. The mean age was 72.2 +/- 10.1 years. Fifty percent of the patients were in NYHA clinical status III or IV. The operative mortality rate was 3.7% (3/90). All patients were followed up for an average of 4.45 years after their operation and the total follow-up was 398 patient-years. RESULTS: At this time of the study, over 80% of the patients are in NYHA class I or II. There were nine late deaths. After 10 years the actuarial survival rate was 80 +/- 12%. Three patients died of valve-related causes (1 endocarditis, 1 structural failure and 1 sudden death). The actuarial rate of freedom from valve-related death was 93 +/- 6% at 10 years. Valve-related complications included two thromboembolic episodes (0.5% patient-year), one endocarditis (0.3% patient-year), one reoperation (0.3% patient-year) and one structural valve failure with calcification and stenosis (0.3% patient-year). After 10 years, freedom from reoperation was 99 +/- 1%, from valve failure 98 +/- 2%, from thromboembolic episodes 95 +/- 4% and from endocarditis 98 +/- 2%. The mean gradient was 18.8 mmHg and mean effective orifice area 1.1 cm2. CONCLUSIONS: With a low rate of valve-related events at 10 years and a low rate of structural deterioration with no leaflet tear, this prosthesis is a reliable alternative for small aortic annuli.

Adult↗
PubMed1996

The majority of autologous cytolytic T-lymphocyte clones derived from peripheral blood lymphocytes of a melanoma patient recognize an antigenic peptide derived from gene Pmel17/gp100.

Anti-melanoma cytolytic T-lymphocyte (CTL) clones were derived from peripheral blood lymphocytes of HLA-A2 melanoma patient LB265 after stimulation with the autologous tumor cell line LB265-MEL, which showed high expression of melanocyte-lineage specific genes. Of 55 CTL clones, 46 recognized HLA-A2-restricted antigens. These 46 CTL clones were studied for their ability to specifically release tumor necrosis factor in the presence of COS cells cotransfected with the HLA-A2 gene and the cDNA of either tyrosinase, Melan-A/MART1, Pmel17/gpl00, gp75/TRP1, or MSH receptor. Six CTL clones recognized the Melan-A/MART1 antigen, whereas the remaining 40 CTL clones recognized a Pmel17/gp100 antigen. These 40 anti-PmelI7/gpl00 CTL clones were all able to lyse T2 cells pulsed with the antigenic peptide YLEPGPVTA, as previously reported. The T-cell receptor beta chain hypervariable region was sequenced and found to be identical in the 15 CTL clones analyzed. Taken together, these data show a high frequency of Pmell7/gp100-specific T cells in autologous antitumor CTL clones derived from peripheral blood of a melanoma patient.

Amino Acid Sequence↗
PubMed1996

[Aortic valve replacement with pericardial bioprosthesis in patients under 60 years of age. Experience over 10 years].

Between July 1984 and December 1993. 110 patients, younger than 60 years, underwent aortic valve replacement with a Carpentier-Edwards pericardial valve. 75.5% were male, with a mean age of 49.6 years (range: 16 to 59 years). Mean clinical status was 2.25. Operative mortality was 0%. All patients but 3 were followed up with a total follow-up of 454 patient-years and an average of 4.8 years. The 10-year actuarial survival is 91 +/- 6%. We observed 8 valve-related complications (1.7% patient-years): 3 cases of endocarditis, 3 structural failures, 1 thromboembolic event, and 1 perivalvular leak. 1 patient died from a valve-related cause, and 2 reoperations were necessary. The 8-year actuarial probability of absence of valve-related death is 99 +/- 1%, thromboembolism 98 +/- 2%, endocarditis 96 +/- 4%; reoperations 96 +/- 4%, and valve failure 97 +/- 3%. The 10-year valve-related complication rate is satisfactory, but the durability of the prosthesis in this group of young patients remains unknown. A longer follow-up is mandatory to draw definitive conclusions.

Actuarial Analysis↗
PubMed1995

[Surgery of valve replacement with pericardial prosthesis].

The ideal artificial heart valve still does not exist among the various cardiac valves available to the clinician. Morbidity and mortality are directly related to the valve itself. Despite the promising hemodynamic results obtained in the 70s with pericardial prosthesis, these valves were progressively abandoned due to their poor long-term resistance. Based on an analysis of the causes of failures, modifications were made in the manufacturing method and current results with pericardial valves has greatly improved, inciting new interest in their clinical use. Today, the pericardium is recognized as a valid substitution material for bioprostheses. Results of long-term series should confirm current studies. Research is under way to determine how to improve pericardium longevity since tissue deterioration remains the limiting factor.

Bioprosthesis↗
PubMed1995

Expression of MAGE genes in transitional-cell carcinomas of the urinary bladder.

Human genes MAGE-1 and MAGE-3 code for distinct antigens, which are recognized on melanoma cells by autologous cytolytic T lymphocytes (CTL). These antigens may constitute useful targets for anti-cancer immunotherapy, since no expression of MAGE genes has been observed in normal tissues other than testis. Out of 57 samples of primary transitional-cell carcinomas of the bladder, 12 (21%) expressed MAGE-1 and 20 (35%) expressed MAGE-3. All but one of the tumors expressing MAGE-1 also expressed MAGE-3. Genes MAGE-2 and MAGE-4, which are closely related to MAGE-1 and MAGE-3, were expressed by 30% and 33% of the tumors respectively. MAGE expression was more frequent in advanced tumor stages: 61% of the invasive tumors (stage > or = T2) were positive for expression of at least one of the four genes, whereas only 28% of the superficial tumors (stages Ta and T1) expressed these genes.

Antigens, Neoplasm↗
PubMed1995

Differences in the antigens recognized by cytolytic T cells on two successive metastases of a melanoma patient are consistent with immune selection.

We have studied the patterns of antigens recognized by autologous cytolytic T lymphocytes (CTL) on two melanoma cell lines derived from metastases that were removed from patient LB33 at several years distance. Cell line LB33-MEL.A was obtained after surgery in 1988. A large number of CTL clones directed against LB33-MEL.A was obtained with blood lymphocytes collected from the patient in 1990. In vitro selection of melanoma cells that were resistant to these CTL clones indicated that at least five different antigens were recognized on LB33-MEL.A by autologous CTL. Four of these antigens were found to be presented by HLA-A28, B13, B44 and Cw6, respectively. The patient remained disease-free until 1993 when a metastasis was detected and was used to obtain cell line LB33-MEL.B. This cell line proved resistant to lysis by all the CTL clones directed against the LB33-MEL.A cells and showed no expression of HLA class I molecules except for HLA-A24. Using LB33-MEL.B cells to stimulate blood lymphocytes collected from the patient in 1994 we derived CTL clones that lysed these cells. All these CTL clones recognized a new antigen presented by HLA-A24. These results suggest that in patient LB33 the melanoma cells may have lost the expression of several HLA molecules under the selective pressure of an anti-tumor CTL response.

Adult↗
PubMed1995

The autologous tissue cardiac valve: a new paradigm for heart valve replacement.

This is a report of early clinical experience with an autologous tissue cardiac valve, which demonstrates the feasibility of making a bioprosthesis in the operating room in 10 minutes at the time of the valve replacement operation. There were 30 implant patients (18 men, 12 women), with ages ranging from 32 to 83 years. Diagnoses included calcified aortic stenosis (n = 16), pure aortic insufficiency (n = 9), and mixed aortic stenosis and insufficiency (n = 5). Associated diagnoses have included chronic renal failure treated with dialysis (n = 1), coronary artery disease requiring concomitant coronary bypass (n = 1), ascending aortic aneurysm requiring resection (n = 3), and mitral insufficiency requiring concomitant mitral valvuloplasty (n = 2). All of the valve replacements were in the aortic position. These implanted patients are being followed up carefully according to the protocol that requires examination every 6 months for the first year and every 12 months subsequently. No patient has been lost to follow-up. Twenty-seven patients are alive and well from 1 to 22 months postoperatively. There were three deaths: two perioperative deaths (one perivalvular leak and one hemorrhage) and one infective endocarditis 1.3 years after valve replacement. All surviving patients were followed up by echocardiographic examination (mean gradient, 15.5 +/- 6.8 mm Hg at 1 year). In conclusion, the feasibility of this method and concept has been demonstrated with implants in 30 patients. The validity of the technique will be judged by clinical results and experiences in children.

Adult↗
PubMed1995

Induction of Plasmodium falciparum sporozoite-neutralizing antibodies upon vaccination with recombinant Pfs16 vaccinia virus and/or recombinant Pfs16 protein produced in yeast.

Pfs16 is a sexual stage/sporozoite-specific antigen of Plasmodium falciparum and is a potential candidate for a sporozoite-neutralizing vaccine. To obtain more information on the function of Pfs16 and to investigate its role during transmission and hepatocyte invasion, immunization experiments were performed with both a Pfs16-specific recombinant vaccinia virus and virus-like particles produced in yeast composed of the hepatitis B surface antigen (HBsAg) and antigen Pfs16 fused to HBsAg. Upon transformation of yeast cells, harbouring a genomic copy of the HBsAg gene, with a plasmid carrying the fusion gene Pfs16-HBsAg (Pfs16-S) virus-like hybrid particles composed of HBsAg and Pfs16-S were formed of a size similar to those present in human sera after infection with the hepatitis B virus. Cells infected with recombinant Pfs16 vaccinia virus synthesized a polypeptide of approx. 16 kDa that reacted with a Pfs16-specific polyclonal antibody. Animals vaccinated with the yeast hybrid particles and/or recombinant vaccinia virus both produced Pfs16-specific antibodies. These antibodies showed no transmission-blocking activity, but they efficiently diminished or abolished in vitro invasion of sporozoites into human hepatoma cells (HepG2-A16) and primary human hepatocytes.

Amino Acid Sequence↗
PubMed1995

Analysis of low-frequency lung impedance in rabbits with nonlinear models.

Lung mechanics was studied in six paralyzed tracheotomized rabbits ventilated with a specially devised computer-controlled ventilator. The target flow waveform contained noninteger multiple frequencies ranging from 0.83 to 6-10 Hz and met a neither-sum-nor-difference criterion to minimize the effects of nonlinearity (B. Suki and K. Lutchen. IEEE Trans. Biomed. Eng. 39: 1142-1151, 1992). The actual flow, however, contained harmonics of the two lowest frequencies. Measurements were performed at mean airway pressure (Paw) levels of 8 and 12 hPa and during histamine-induced bronchoconstriction. Smooth impedance curves were observed in unchallenged rabbits at low mean Paw levels. In contrast, unrealistic impedance fluctuations, suggestive of cross talk from the unwanted frequency components in the flow input, were seen at high mean Paw levels and during acute bronchoconstriction. Model analysis was performed by using the actual flow signal as an input to various nonlinear models. The impedance fluctuations observed at high mean Paw levels were well simulated by a model featuring a volume-dependent elastance, and those observed after histamine were almost perfectly reproduced by a model where resistance increased with the reciprocal of lung volume. We conclude that impedance data biased by cross talk may provide useful information on the presence and nature of respiratory system nonlinearities.

Airway Resistance↗