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M Marchand

Publications and source records attributed to M Marchand.

At least 109 records · Page 6Linked to original sources
PubMed1983

Immunogenic variants obtained by mutagenesis of mouse mastocytoma P815. VI. Occasional escape from host rejection due to antigen-loss secondary variants.

After mutagenesis of mouse mastocytoma P815, it is possible to obtain variant (tum-) clones that are almost always rejected by syngeneic DBA/2 mice. Most tum- clones express new variant-specific antigens that can be detected by cytolytic T cells (CTL). Occasionally, mice injected with tum- variants eventually develop progressive tumors. Cells from these tumors were analyzed for antigen expression with variant-specific and P815-specific CTL clones. Out of 13 tumors examined, 11 were composed of cells that had clearly lost a variant-specific antigenic determinant. These results indicate that tum- variants induce a specific host rejection response which usually results in complete elimination of the variant cells, but that occasional antigen-loss constitutes an important mechanism of escape. The loss of a variant-specific antigenic determinant from one tum- clone that had escaped rejection allowed the detection of a residual variant-specific determinant. This was demonstrated by isolating a new CTL clone that lysed both the original tum- clone and its antigen-loss variant, but not other P815 targets. Thus, some complex transplantation antigens can be separated into independent determinants by using antigen-loss variants.

Animals↗
PubMed1983

Increased frequency of immunogenic variants obtained by repeated mutagen treatment of mouse mastocytoma P815.

A previous report from this laboratory demonstrated that treatment of mouse mastocytoma P815 with the mutagen N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) produces tumor cell variants that are unable to form tumors in syngeneic animals. We examined whether repeated mutagen treatment could increase the frequency of tum- variants above that obtained after a single treatment. This was found to occur with frequencies increasing from a few percent after 1 treatment to more than 90% after 8 treatments. Moreover, uncloned survivor populations obtained after 8 or more MNNG cycles that contained such a high proportion of tum- variants had a markedly decreased tumorigenicity for syngeneic mice. As reported for tum- variants obtained after 1 mutagen treatment, several tum- variants obtained after repeated treatments carried new variant-specific antigens that elicited a specific cytolytic T cell response. Some of these tum- antigens were found to consist of multiple determinants that could be lost independently. We observed that the resistance of the mutagenized populations to MNNG increased gradually with the number of mutagen treatments. In addition, some tum- variants obtained after 8 mutagen treatments showed a reduced sensitivity to mitomycin C.

Animals↗
PubMed1983

[Surgical treatment of congenital aortic valve constriction with associated obstructive cardiomyopathy. Perioperative left intraventricular gradient treated with beta blockers. Apropos of a case].

The authors report a case of congenital valvular aortic stenosis associated with echocardiographic and angiographic appearances of hypertrophic obstructive cardiomyopathy. After valvular replacement and partial myotomy a high intraventricular pressure gradient (125 mmHg) with low intra aortic pressure was recorded. High dose intravenous propranolol (25 mg in 2 hours) reduced this gradient to 50 mmHg allowing cardiopulmonary bypass to be discontinued. This clinical combination is associated with a risk of aggravation of the intra-ventricular obstructive phenomenon when the obstacle to left ventricular ejection is relieved: surgical myotomy was performed in similar, previously published cases. High doses betablocker therapy can be performed in similar, previously published cases. High dose betablocker therapy can be useful in this association and it may also be instituted when right intraventricular pressure gradient increase after relief of pulmonary valvular stenosis.

Adolescent↗
PubMed1983

Tricuspid atresia. Results of treatment in 115 children.

We present our experience in the management of tricuspid atresia in 115 children. The anatomic data are categorized as follows: type I, 83.5%, type II, 16.5%. Type IB is the most frequent, representing 63.5% of all the cases. Each patient was operated upon one to four times. The age at first operation ranged from 10 days to 20 years. The first operation was a shunt in 94 children, a Fontan operation in four, and banding of the pulmonary artery in 17. Hospital mortality for the first operation was 12.2%, significantly higher in children under 6 months and in those having Waterston shunts. Potts and Blalock-Taussig operations give low long-term mortality; although few (six) have been done, Potts shunts also seem to give good long-term palliation in this series. The Glenn anastomosis is a good operation when performed after a systemic-pulmonary arterial shunt. The Fontan operation was performed in 24 children (hospital mortality 16.6%). There have been no late deaths after the third month postoperatively. Mean follow-up for this operation is only 2 years, but 88% of the survivors lead a normal life, two thirds of them receiving no treatment. There has been one reoperation for stenosis of a Dacron conduit with a good result. Late arrhythmias are well tolerated. In conclusion, the Fontan procedure is a good operation, but palliative procedures still allow good long-term survival.

Actuarial Analysis↗
PubMed1982

[Results of the repair of isolated coarctation of the aorta during the 1st 6 months of life, Apropos of 46 cases].

Between 1972 and 1978, forty-six infants under six months of age underwent surgery for isolated coarctation of the aorta. These forty-six patients represent 32% of the total number of infants aged less than six months who had surgery for coarctation of the aorta during the same period. At the time of operation, 41% were aged less than one month and the youngest was five days old. The main cause for surgery was heart failure in infants under one month (14/19) and severe systemic hypertension (150 to 300 mm Hg) in the one to six month age group (18/27). Overall mortality rate in our series was 17%. Six of the eight infants who died were under one month of age. Recoarctation occurred in 31,5% of infants; in eight cases the first surgical procedure had been done before one month of age. A second procedure was necessary in four cases. Early surgical repair of severe coarctation diagnosed during the first six months of life leads to functional improvement and avoids residual hypertension. After repair, the main risk is recoarctation.

Aortic Coarctation↗
PubMed1982

[Right coronary artery arising from the pulmonary artery. Surgical treatment].

The authors report the case of an anomalous right coronary artery arising from the pulmonary artery. The patient was an active 18 years old boy who had a continuous murmur with diastolic accentuation, the cause of which was determined at angiography. There were electrical and echocardiographic signs of moderate left ventricular dilatation and thallium scintigraphy showed a myocardial perfusion defect. These were the only detectable consequences of this rare malformation. Normal coronary circulation was reestablished surgically, the indication being the risk of sudden death which has been previously reported rather than acute myocardial ischemia.

Adolescent↗
PubMed1982

[Results of surgical treatment of aortic coarctations in the 1st 6 months of life. Apropos of 142 cases].

142 infants under 6 months of age were operated on for coarctation of the aorta from 1972 to 1978. Coarctation was isolated in 46 (32.4%) and associated with another heart defect in 96. Surgery was decided upon because of congestive heart failure sometimes associated with arterial hypertension refractory to medical treatment: 9 patients died during surgery. 89 underwent Crafoord's operation and in 44 ligature of the subclavian artery or aortoplasty using the subclavia were carried out. Early postoperative death rate was 30.9% and 13 patients (13.2%) died later. Recoarctations occurred in 25 patients (27%); more than half of these patients were less than 1 month-old at the time of surgery. Recoarctation was more frequent (46.4%) in cases with than in cases without (18.7%) aortic hypoplasia and it was more severe (5 out of 7 deaths) when there was an associated cerclage resulting in a double obstacle to right and left ventricles ejection.

Aortic Coarctation↗
PubMed1981

[Recurrent neurological accidents due to pulmonary arteriovenous fistulae (author's transl)].

The authors report a case of recurrent cerebral embolism in a 43-year-old patient with a familial form of Rendu-Osler-Weber disease and review their experience of 19 cases of pulmonary arteriovenous fistula. Neurological complications were rare but considerably aggravated the disease. They were due to a significant right/left shunt but remained unpredictable, being unrelated to peripheral arterial saturation. The pathophysiological mechanisms and therapeutic possibilities are discussed.

Adult↗
PubMed1981

[Clamping of the thoracic aorta in a hypertensive patient with coronary disease. An indication of sodium nitroprusside (author's transl)].

In patients with cardiac failure, coronary disease or arterial hypertension, clamping of the aorta results in increased filling pressure of the left ventricle which may produce or increase subendocardial ischaemia with consequent aggravation of the ventricular insufficiency. And the higher the clamping the greater the risk. This vicious circle can be broken by sodium nitroprusside, which has potent and reversible vasodilator properties. The drug is indicated whenever the left ventricular filling pressure rises above 5 mmHg. These considerations are illustrated by the descriptions of a case where sodium nitroprusside ensured blood circulation in the lower limbs and intra-abdominal organs after clamping of the aorta above the coeliac artery in a high risk cardiac patient.

Aorta, Thoracic↗
PubMed1981

Surgical treatment of anomalous origin of the left coronary artery in infancy and childhood. Early and late results in 20 consecutive cases.

From 1972 to September, 1979, 20 patients underwent transplantation of the anomalous left coronary artery to the aorta, either directly or via a graft. Correction of ischemia-induced mitral insufficiency was associated in eight patients and a postinfarction left ventricular scar was excised in 12. Operative mortality was high among patients under 1 year of age (4/5). Among older children it was 15%. There were not late deaths among patients surviving the operation (mean follow-up 3 years). All but one had marked clinical improvement and reduction of cardiomegaly. Eleven patients underwent angiographic control, with a patent graft or anastomosis demonstrated in every case. Operation is advocated for patients over 1 year of age. The best treatment of symptomatic infants remains controversial.

Aorta↗
PubMed1981

Modified technique for correction of tricuspid atresia.

This study presents a new technique for correction of tricuspid atresia. All 13 patients operated upon had the same form of the anomaly, with the great arteries normally related. The principle is to conserve the pulmonary valve and anulus of the patient in its anatomic position and to exclude the hypoplastic right ventricle. Because there is no need for closing the ventricular septal defect, the risk of heart block and residual left-to-right shunts is avoided. Deaths are related to questionable indications for two patients and to a bilateral pneumothorax for the third one. The long-term follow-up (5 years for the first patient) shows good results for the 10 survivors. Six of them are in Class 1 of the New York Heart Association and four are in Class II.

Adolescent↗