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Biomedical subjects

M Lefevre

Publications and source records attributed to M Lefevre.

At least 73 records · Page 4Linked to original sources
PubMed1983

The values of calcitonin and carcinoembryonic antigen in the treatment and management of nonfamilial medullary thyroid carcinoma.

Thirty-one patients were studied to evaluate the prognostic value of both calcitonin (CT) and CEA levels determined after the initial treatment in medullary thyroid carcinoma (MTC). Twenty-seven patients were evaluated three to nine months after initial treatment and four others afterwards. The CT and CEA levels were significantly higher and the survival rate lower in the eight patients with residual clinical disease as compared to the 19 patients in complete clinical remission. In patients in complete clinical remission, 11 had elevated CT level after treatment, and all had initial lymph node involvement. Five of these 11 relapsed and one died. None of the eight patients with normal CT levels after treatment relapsed. CEA levels were always abnormally high when patients relapsed. Fourteen patients in complete remission with high CT levels were followed for more than four years. Six had normal CEA levels and no relapse was observed. Eight of the 14 had pathological CEA levels and six of eight relapsed: five of these six patients presented CEA elevation from six to 36 months before the clinical relapse. In two of these six patients, a venous catheterization sampling method demonstrated infra clinical local recurrence. In two patients with liver metastases, the time course changes of CT and CEA levels were different and CEA appeared to be a more sensitive tumor marker than CT. These data are consistent with previous data concerning the values and limits of CT level for the management of MTC. Furthermore, this study demonstrates the prognostic significance of CEA determination in MTC. CEA appears to be a sensitive selective tumor marker capable of defining a high-risk subgroup.

Adult↗
PubMed1983

Medullary thyroid carcinoma: prognostic factors and treatment.

Seventy-five patients with medullary thyroid carcinoma (MTC) have been treated at Institut Gustave-Roussy from 1932 to 1979. Of these, 13 patients had distant metastases and received palliative treatment, their median survival was 3 years. Sixty-two patients with MTC limited to the neck received curative treatment; 6 had exclusive external radiotherapy for inoperable disease and 56 were surgically treated: 23 by total thyroidectomy and 33 by partial thyroidectomy. After surgery 29 patients received external radiotherapy for cervical lymph node involvement (25/29) and/or incomplete surgical resection (12/27). The survival rate was 69% at 5 years and 48% at 10 years. It was lower in patients with distant metastases at presentation (p less than 10(-5)), with tumoral infiltration of the posterior tissue planes (p less than 0.025) and in patients in whom surgical excision had not been satisfactory (p less than 0.01). It was not correlated with cervical lymph node involvement probably because those patients with lymph node involvement had been irradiated. The 29 patients who received post-operative cervical radiotherapy had initially more extensive local disease (p less than 0.05) than the 27 patients treated by surgery alone, nevertheless their survival was slightly higher. No difference in survival rate was observed between patients treated by total thyroidectomy or partial thyroidectomy, among whom only 4 local recurrences occurred. Three of the 6 patients treated with external radiotherapy alone experienced long survival (4, 7 and 10 years) and a fourth is still in clinical remission 4 years after treatment. The effectiveness of chemotherapy in patients with metastases was poor, only one patient out of 6 had a partial remission following a treatment by adriamycin. In the familial form and multiple endocrine neoplasia type II, total thyroidectomy appears to be indicated. In the sporadic cases, partial thyroidectomy is usually sufficient. External radiotherapy is effective in MTC and seems to be able to eradicate small foci of residual tumor; it is indicated when surgical excision is impossible or incomplete.

Adolescent↗
PubMed1982

Dietary cadmium, zinc and copper: effects on chick lung morphology and elastin cross-linking.

Day-old White Leghorn cockerels were divided into seven dietary groups and fed one of the following diets: 1) a casein-based basal diet; 2) a casein-based diet supplemented with 10 mg/kg cadmium, 3) 100 mg/kg cadmium, 4) or 800 mg/kg zinc; 5) a casein-based diet pair-fed to the 100 mg/kg Cd group; 6) a spray-dried nonfat milk-based diet with no added copper, or 7) a spray-dried nonfat milk-based diet supplemented with 5 mg/kg copper. At termination (5 weeks), the birds were killed, and the effects of the diets on selected features of lung composition and morphology were assessed. Body weights were reduced in the 100 mg/kg Cd, pair-fed, and Cu-deficient groups when compared to their controls (casein-based or milk-based copper-supplemented diets). There were no differences in lung weights (expressed relative to metabolic body size) among the groups, although copper deficiency did result in a slight decrease in the dry to wet weight ratio of lung. Lung elastin content and the desmosine content in elastin were significantly lower in the Cu-deficient group and tended to be lower in the group fed 800 ppm Zn. Significant alterations (enlargement of the tertiary bronchial lumen) in morphology were also observed in lungs from both the 100 mg/kg Cd and Cu-deficient groups. Alteration in lung morphology observed in the 100 mg/kg Cd group could not be explained by changes in the elastin content of lung.

Animals↗
PubMed1982

[Complications of myocardial infarction between the 2d and 4th week].

The complications of myocardial infarction after transfer from the Coronary Care Unit on the 6th day were analysed bu a retrospective study of 3,460 computerised case reports (1973-1980). The mortality rate was 6% (1/3 of hospital deaths) in the period from the 7th day to discharge from hospital (14th to 30th day). Cardiac arrest as not uncommon (20% of all cardiac arrests) but the prognosis was better thn during the initial phase (p less than 0.05) as the mechanism was more commonly ventricular fibrillation or tachycardia (p less than 0.05). This series was compared with a similar population from 1970-1973; an improvement was observed in global hospital mortality (27% previously compared to 17%, in the study series, p less than 0.001). As the population were comparable, this phenomenon seems to be related to better treatment of shock and cardiac failure and the advances in cardiac surgery during the initial phase of infarction. Thd commonest mechanical complication was ventricular aneurysm; its occurrence does not influence the vital prognosis during this period. The incidence of cardiac arrest and death due to cardiac failure is not negligible after the first week of myocardial infarction. Therefore, we do not believe that the hospital period should be reduced after myocardial infarction. Special training of the nursing staff is essential for the successful treatment of these complications. The global prognosis could be improved by the rehabilitation of digitalis therapy and the introduction of new sympathomimetic amines in the acute phase of myocardial infarction.

Adult↗
PubMed1981

[Demonstration in a thyroid cancer of vesicular structures similar to ultimobranchial-type vesicles described in mice].

An immunohistochemical and electron microscopy study has allowed us to find in a human thyroid cancer, follicle differentiation associating in a characteristic architectural pattern C cells, ciliated cells and follicular cells. Ultrastructural features were similar to those described in the normal adult Mouse thyroid by Wetzel and Wollman [1] and interpreted by them as a second type of thyroid follicle of ultimobranchial origin. The discovery of these structures within metastatic lymph nodes excludes normal thyroid follicle contamination. The presence of these neoplastic structures lead us to make the hypothesis of a stem cell of ultimobranchial and endodermal origin common to all the cells described.

Animals↗
PubMed1980

Aorta elastin turnover in normal and hypercholesterolemic Japanese quail.

The turnover and degradation of mature elastin from the aortae of Japanese quail were estimated following injection with L-[U-14C]lysine by measuring the changes in specific activity of L-[U-14C]lysine and 14C-labelled desmosine and isodesmosine (crosslinking amino acids derived from lysyl residues) in elastin over a 39-week period. Only 5% of the variation in radioactivity could be attributed to changes in time. Therefore, it was concluded that the best estimates of mature elastin turnover are only quantifiable in years. Dietary cholesterol in amounts sufficient to induce plaque formatioin and fragmentation of the elastic lamina in the aorta did not significantly influence turnover time. It would appear that once the total pool of elastin in aorta is stabilized as mature fibers it is not subject to proteolysis or resynthesis of sufficient magnitude to result in measurable turnover.

Animals↗
PubMed1980

[Mid-systolic click syndrome, coronary spasm and sudden death. General review apropos of a tracing from terminal Prinzmetal's angina, recorded by the Holter method].

The authors review the literature on arrhythmias and ST changes, the principal causes of sudden death in the mid systolic click-late systolic murmur (SC-SM) syndrome, having recorded the ECG during sudden death of a patient with this syndrome by Holter monitoring. This would also appear to be the first reported case of sudden death recorded by this technique. It showed that death was caused by ventricular fibrillation which was preceded by a clinical and electrical episode of Prinzmetal angina. Hypotheses explaining the abnormalities of ventricular repolarisation and rhythm in so-called "idiopathic" SC-SM syndrome are reviewed. Special attention is paid to studies suggesting the participation of coronary spasm and autonomic nervous system disturbances. In conclusion, the authors underline: - the value of ambulatory electrocardiography in patients with the SC-SM syndrome and especially in a defined high risk group; - the value of testing for coronary spasm when coronary angiography is envisaged; - the need for better management with antiarrhythmic therapy. The indications of betablockade are discussed as these drugs are thought to favourise coronary spasm.

Angina Pectoris↗
PubMed1979

Partial characterization of a tropoelastin precursor isolated from chick aorta.

Evidence is presented that indicates tropoelastin is derived from a soluble elastin with a molecular weight of 95000. Tropoelastin and its proposed precursor were isolated from the aortas of copper-deficient chicks. Although it is doubtful that the proposed precursor is an initial product of elastin translation, i.e., a proelastin, it is proposed to be at least a truncated form of proelastin that is converted to tropoelastin. The key to its isolation was the presence of alpha 1-antitrypsin at each step in the purification procedure. The first 11 amino acid residues at the NH2 terminal of the proposed tropoelastin precursor (GGVPGVAVPGGV) are the same as those for tropoelastin. Its amino acid composition is similar to that of tropoelastin, except for higher amounts of acidic amino acid residues. Further, the proposed precursor contains a limited number of aldehydic functions, presumably in the form of peptidyl allysine. This was taken as an indication that the proposed precursor serves as a substract for lysyl oxidase. Under the conditions used for the isolation, the precursor appeared to be in higher concentrations than tropoelastin in aorta extracts from copper-deficient chicks.

Amino Acid Sequence↗
PubMed1979

Cytogenetic investigation on leukocytes of workers exposed to metallic mercury.

A cytogenetic analysis was performed in 28 mercury-exposed subjects as well as eight control subjects from the same chloralkali plant and in 12 healthy controls from the "general population." No chromosomal effects could be demonstrated in the mercury-exposed population in comparison with both control groups. Also no effect of smoking was observed. From the study it seems obvious that mercury, although it is capable of producing chromosomal damage even at low exposure levels, will not be harmful in this respect when adequate protection measures are taken.

Adult↗
PubMed1978

Inhibition of elastolysis by proteinase inhibitors from chick plasma and aorta.

Chick plasma contains inhibitor(s) against trypsin and elastase which also appear to retard the degradation of tropoelastin by arterial tissue extracts. Chick aorta extracts also contain similar inhibitors against elastase and trypsin. Both levels of the plasma inhibitor(s) and inhibitor(s) extracted from thoracic aorta increase during early stages of growth and maturation. There is a three- to four-fold increase in the levels of the inhibitor(s) in chick plasma and aorta between one to four weeks after hatching. Of particular interest are the observations that the presence of the inhibitor(s) retards the conversion of soluble elastin (tropoelastin) to smaller elastin peptides. Subsequently, it is speculated that in addition to other vital roles, such proteinase inhibitors may also act in regulating elastogenesis and elastin fiber formation.

Animals↗
PubMed1977

[Study of the association between aortic coarctation and congenital mitral insufficiency (excluding atrioventricular canals)].

Coarctation of the aorta is accompanied by congenital mitral incompetence in 3% of cases, and this combination worsens the prognosis. A series of 23 cases is reported, and the treatment analysed. In 6 cases only medical treatment was used, either because death was rapid or, on the contrary, satisfactory progress made it possible to wait for the normal age for resection and suture of the coarctation. In one case the severity of the mitral incompetence required early valvular replacement, while the minimal coarctation was ignored. Usually (16 cases) a Crafoord operation is carried out as a first stage, and of the 13 children still alive, 8 had their mitral incompetence improved or stabilised; but in 5 it became worse, requiring mitral valve surgery from 1 to 7 years later. Post mortem study showed the multiplicity of mitral lesions present, and explains the difficulty of mitral 'plasty' operations, which are the best solution in children.

Adolescent↗