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Biomedical subjects

J L Michaud

Publications and source records attributed to J L Michaud.

At least 37 records · Page 2Linked to original sources

[Surgical treatment of pulmonary metastases of colorectal cancers. 8-year survival and main prognostic factors].

OBJECTIVE: In order to achieve a better definition of the indications for surgical excision of pulmonary metastases in colorectal cancer (CCR), a retrospective study of the eight year survival of patients who had been operated on was carried out with reference to the principal prognostic factors. METHODS AND RESULTS: Between May 1986 and December 1997, 38 patients had an excision for pulmonary metastases for CCR. The mean delay between diagnosis of the metastases and surgical treatment of the CCR was 39 +/- 24 months (0-98). Thirty two patients (84%) had a single pulmonary metastasis. The mean diameter of the metastasis was 38 +/- 22 mm. Twenty metastases had a diameter < 30 mm. Five patients had a locoregional recurrence of their CCR before pulmonary surgery. Fourteen patients had an abnormally elevated level of carcinoembrionic antigen (ACE-CEA) before the pulmonary excision. Five pneumonectomies, 23 lobectomies, 1 bilobectomy and 11 atypical resections were carried out. A lymph node clearance was performed in 25 cases. Six patients (16%) had an associated excision of an hepatic metastasis. The in-hospital mortality was 2.6%. Chemotherapy was associated with a pulmonary excision in 17 patients (46%). The mean survival was 2.7 years (0.13-8.7 years). The survival at one year was 89 +/- 5.2% and at five years 35.2 +/- 10.1% and at eight years 18.8% +/- 10.3%. Age, sex, histological stage of the primary tumor, the size and the delay in appearance in the pulmonary metastases, the number of metastases, the preoperative CEA, the operative technique and the perioperative chemotherapy did not influence the levels of survival at five years. At the same time associated excision of an hepatic metastasis did not worsen the prognosis at five years. CONCLUSION: Complete excision of pulmonary metastases in a colorectal cancer allows for significantly longer survival. This study associated with a literature review may help in advancing towards better selection of surgical candidates.

Adult↗

Development of neuroendocrine lineages requires the bHLH-PAS transcription factor SIM1.

The bHLH-PAS transcription factor SIM1 is expressed during the development of the hypothalamic-pituitary axis in three hypothalamic nuclei: the paraventricular nucleus (PVN), the anterior periventricular nucleus (aPV), and the supraoptic nucleus (SON). To investigate Sim1 function in the hypothalamus, we produced mice carrying a null allele of Sim1 by gene targeting. Homozygous mutant mice die shortly after birth. Histological analysis shows that the PVN and the SON of these mice are hypocellular. At least five distinct types of secretory neurons, identified by the expression of oxytocin, vasopressin, thyrotropin-releasing hormone, corticotropin-releasing hormone, and somatostatin, are absent in the mutant PVN, aPV, and SON. Moreover, we show that SIM1 controls the development of these secretory neurons at the final stages of their differentiation. A subset of these neuronal lineages in the PVN/SON are also missing in mice bearing a mutation in the POU transcription factor BRN2. We provide evidence that, during development of the Sim1 mutant hypothalamus, the prospective PVN/SON region fails to express Brn2. Our results strongly indicate that SIM1 functions upstream to maintain Brn2 expression, which in turn directs the terminal differentiation of specific neuroendocrine lineages within the PVN/SON.

Amino Acid Sequence↗

[Surgical treatment of pulmonary metastasis of colorectal cancer. Prognostic survival factors].

SURVIVAL RATES: Less than 5% of patients with pulmonary metastasis from colorectal carcinoma will survive at 5 years, but 30% will survive at 5 years after surgical treatment. MAIN PROGNOSTIC FACTORS: The number of nodules, presence of regional lymph node metastases, disease-free interval between treatment of the primary tumor and development of metastasis as well as serum CEA level are the main prognostic discriminants. INDICATIONS FOR SURGERY: An aggressive operative approach is indicated even when there are pulmonary and extra-pulmonary localizations. Repeat thoracotomy is warranted for recurrent disease.

Carcinoembryonic Antigen↗

Mitral valve replacement with the St. Jude Medical prosthesis: a 15-year follow-up.

BACKGROUND: A retrospective study was conducted to analyze the results of St. Jude Medical mitral valve replacement. METHODS: From January 1979 to December 1989, 870 patients (54% women, 46% men; mean age, 55.8 +/- 6.2 years) underwent mitral valve replacement with the St. Jude Medical prosthesis. Of these operations 616 were isolated mitral valve replacements and 254 were double valve replacements. Coronary artery bypass grafting was performed concomitantly in 55 patients (6.3%). RESULTS: Overall, early mortality was 5.05%, with 4.2% for the isolated mitral valve procedure and 7.08% for the double valve replacement. Follow-up at 15 years was complete in 859 patients (98.74%). Mean follow-up time was 93.5 months, for a total of 6,436 years. Actuarial survival at 15 years was 59.5% +/- 5%, 60.5% +/- 6%, and 56.9% +/- 9%, for the entire group, the isolated mitral valve and double valve procedures, respectively. Multivariate analysis identified age, sex, hospital stay, and preoperative mitral regurgitation as independent prognosis factors for overall mortality. Of 606 patients alive at the latest follow-up, the New York Heart Association class improved significantly (from 67% class III/IV before the operation to 88% class I/II after the operation). All patients received warfarin to maintain an international normalized ratio between 3.5 and 4. The linearized rates (% per patient-year) of thrombosis, thromboembolism, and major hemorrhage were, respectively, 0.21, 0.75, and 0.94 for the entire group; 0.18, 0.67, and 0.88 for the isolated mitral valve operation; and 0.15, 0.92, and 1.08 for the double valve replacement. For the entire group the freedom from thrombosis and thromboembolism at 15 years was 98.1% +/- 1% and 88% +/- 4%, respectively. No case of structural dysfunction occurred. The freedom from paravalvular leak and endocarditis at 15 years was 95.3% +/- 2% and 97.3% +/- 2.4%, respectively. The probability of remaining free from reoperation at 15 years was therefore 95.6% +/- 2.5%. CONCLUSIONS: These results confirm that the St. Jude Medical valve is a reliable prosthesis with very low thrombosis and thromboembolism rates, allowing the use of a low dose of anticoagulation with an international normalized ratio of about 3.

Aged↗

Aggressive surgical management in localized pulmonary mycotic and nonmycotic infections for neutropenic patients with acute leukemia: report of eighteen cases.

OBJECTIVE: To prevent hemoptysis and relapse during subsequent chemotherapy-induced neutropenia in patients with localized forms of invasive pulmonary aspergillosis, we adopted an aggressive surgical approach. METHODS: From 1988 to 1996, 18 patients with hematologic diseases were referred with the diagnosis of localized invasive pulmonary aspergillosis. The diagnosis was based on clinical features, failure to respond to antibiotic therapy, an air crescent sign suggestive of aspergillosis on the computed tomographic scan (39%), and retrieval of fungi by bronchoalveolar lavage (44%). RESULTS: The following procedures were done: one pneumonectomy, four bilobectomies, seven lobectomies, six wedge resections, and one lobectomy with wedge resection (one patient had two procedures). No perioperative deaths or complications occurred. The histologic examination confirmed the diagnosis of invasive pulmonary aspergillosis in 12 patients. The six other diagnoses were as follows: one case of classic aspergilloma, one case of pneumonia, and four cases of pulmonary abscess. According to univariate analysis, thoracic pain was less common in the group with noninvasive pulmonary aspergillosis (1/6) than in the group with invasive pulmonary aspergillosis (8/12) (p < 0.05). Sixteen patients required subsequent hematologic treatments. Sixty-six percent of the patients are alive with a mean follow-up of 29.1 +/- 27.8 months (range 2 to 103 months), with no statistically significant difference between the invasive and the noninvasive pulmonary aspergillosis groups. Five patients died of a recurrence of their malignant disease at a mean of 17.2 +/- 12.5 months (range 2 to 30 months), and one had a cerebral recurrence of Aspergillus infection during a bone marrow transplantation 3 months later. CONCLUSION: Aggressive surgical management radically improves the prognosis of invasive pulmonary aspergillosis, even if the surgical indications include some nonmycotic infections because of the difficulty in establishing the clinical diagnosis.

Acute Disease↗

[Mycotic aneurysm in acute bacterial mitral valve endocarditis. Apropos of a case].

A 24 year old man presented with acute endocarditis of the mitral valve. Rupture of a mycotic cerebral aneurysm on the 20th day was successfully treated by interventional catheterisation. Several days later, he underwent mitral valvuloplasty under good conditions. The postoperative period was uncomplicated but emergency surgery was required for a mycotic aneurysm of the superior mesenteric artery. The patient was discharged from hospital without severe neurological sequellae and with a continent mitral valve.

Adult↗

[Thymic and bronchial neuroendocrine tumors in multiple endocrine neoplasia type 1. GENEM1].

OBJECTIVES: Multiple endocrine neoplasia type 1 (MEN 1) mainly affects parathyroid glands, pancreatic islets and pituitary gland. The aim of this study in 95 MEN 1 patients was to examine less frequent localizations thymic and bronchic neuroendocrine tumors (NET). PATIENTS AND METHODS: Two cases of bronchic NET were observed, both in women, and 4 cases of thymic NET, all in men, giving a prevalence of 7.3%. These NET were often asymptomatic. A metastatic diffusion was observed in 3 cases. Elevated plasma levels of glycoprotein hormone alpha subunit (SU) and FSH were observed in 3 and 1 cases respectively. Immunohistochemistry indicated the tumor cells to be frequently positively stained for HCG alpha and FSH. DISCUSSION: We conclude that all patients with MEN 1 should undergo screening for thoracic NET, especially in high risk familial subgroups and in case of elevated plasma alpha SU or FSH.

Adult↗

The dorsoventral polarity of the presumptive limb is determined by signals produced by the somites and by the lateral somatopleure.

When it first appears at stage HH16, the wing bud is already polarized along the dorsoventral axis. To study the mechanisms leading to the establishment of its dorsoventral polarity, we decided to focus our attention on an earlier stage (HH13). Using the quail-chick chimera system, we first show that the presumptive wing mesoderm occupies the medial half of the somatopleure at the level of somites 15-20. The corresponding ectodermal area, however, will only give rise to the apical ectodermal ridge. The rest of the limb bud ectoderm originates from the ectoderm overlying the paraxial and the intermediate mesoderms for its dorsal aspect and the lateral somatopleural mesoderm for its ventral aspect. We next used five experimental paradigms to show that the dorsoventral polarity of the presumptive limb is determined by its environment. Thus, presumptive limb regions flanked on two sides by rows of somites give rise to bidorsal limb buds, indicating that the somites produce a dorsalizing factor. In addition, insertion of filters laterally to the presumptive limb region also results in bidorsal limb buds, suggesting that the lateral somatopleure produces a ventralizing factor. We propose a model in which the polarizing activity of these two signals is mediated by the morphogenetic movements of the presumptive dorsal and ventral ectoderms, which carry the dorsoventral information over the limb bud mesenchyme.

Animals↗

[Heart-lung transplantation and cystic fibrosis. Indications and results].

BACKGROUND: Heart lung transplantation for++ cystic fibrosis is now performed in patients with severe lung disease but the experience is still scarce with the exception of some specialized centers. PATIENTS AND METHODS: Twenty-one patients underwent heart-lung transplantation between September 1989 and November 1994 in our institution, with a high standard of reliability in tracheal anastomosis and with a low incidence of hospital mortality (5%). RESULTS: The actuarial patient survival is 90.2% (95% confidence interval, 70 to 97%) at 1 year and 75.7% (95% confidence interval, 51 to 90%) at 3 and 4 years. The mean forced expiratory volume in 1 second (FEV1) increases from 20.1% predicted preoperatively to 76.1%. CONCLUSION: Despite the presence of airway pathogens, these results confirm that heart-lung transplantation for cystic fibrosis leads to a pronounced improvement in lung function and good rehabilitation after surgery. The two main obstacles are the shortage of donor organs and the possibility of late deterioration in lung function with a progressive airflow obstruction.

Adolescent↗

Natural history of Alström syndrome in early childhood: onset with dilated cardiomyopathy.

Alström syndrome is an autosomal recessive disorder characterized by cone-rod dystrophy, obesity, hearing impairment, and diabetes caused by insulin resistance. By reviewing the charts of eight patients followed for periods of 2 to 22 years, we established the natural history of this syndrome during childhood. Five patients, in four families, were seen between the ages of 3 weeks and 4 months with a dilated cardiomyopathy, a previously unrecognized feature of the syndrome. Photophobia and nystagmus were first documented in the eight patients between the ages of 5 months and 15 months. In all patients, electroretinography initially showed a severe cone impairment with mild (2/8) or no (6/8) rod involvement. Electroretinograms, obtained again at ages 9 to 22 years for four patients, revealed extinguished rod-and-cone responses. Obesity developed during childhood in seven patients, in at least three of them before age 2 years. Hearing impairment (5/8) and diabetes/glucose intolerance (4/8) were diagnosed at the end of the first decade or during the second decade. This constellation of features should facilitate early diagnosis of the syndrome.

Adolescent↗

Surgical resection of pulmonary metastases from colorectal carcinoma. Five-year survival and main prognostic factors.

Between 1986 and 1994, 19 patients underwent pulmonary resection for metastatic colorectal carcinoma. The mean interval between colon resection and appearance of pulmonary metastasis was 41 +/- 21 months. All the patients had no more than two metastases. Wedge resection alone or associated with lobectomy was performed in four patients, lobectomy in ten, and pneumonectomy in five. One patient died within the month after surgery. Mean follow-up was 35 +/- 26 months. The 5-year survival rate was 38.7%. Repeat thoracotomy for recurrent metastases was performed in one patient. The disease-free interval, the size of metastases, the type of pulmonary resection, and the location and the stage of primary cancer had no apparent influence on survival, but the survival rate at 4 years was 25% for patients with high carcinoembryonic antigen (CEA) level versus 80% for those with low CEA level. We conclude that, at least when the number of metastases is less than two, resection of colorectal lung metastasis is safe and effective.

Aged↗

[Constrictive pericarditis after cardiac surgery].

Constrictive pericarditis is a rare complication of cardiac surgery. Among 7851 patients who underwent cardiac surgery at Nantes University Hospital, postoperative constrictive pericarditis was diagnosed in 5 patients: 0.63%. All patients were men aged 49 to 77 years (mean 62.5) Four patients underwent coronary artery bypass graft surgery and one patient required mitral and aortic valve replacement. The mean time to onset of symptoms after the first operation was 21 months. The main clinical symptom was right ventricular failure. In all patients, the diagnosis was established by right catheterization which showed diastolic dip-plateau. A radical pericardectomy was performed in all but one of the patients, who was treated medically. Clinical signs resolved in all five patients. The diagnosis of constriction after cardiac-surgery is not easy, as the symptoms are non-specific. A symptomatic patient believed to have myocardial failure after cardiac-surgery could therefore actually instead have occult constriction.

Aged↗

Complete myocardial revascularization through a right thoracotomy.

We report the case of a 57-year-old woman who benefited from a complete revascularization of the heart, including a circumflex marginal coronary bypass grafting, through a right thoracotomy. This approach avoids sternal wound complications that can occur after high-dose mediastinal radiotherapy and omental flap reconstruction on the sternum.

Adenocarcinoma↗

[Heart transplantation, cardiomyoplasty or artificial heart?].

This is a difficult question and the answer is uncertain. The authors review the state of the art of the three methods in 1993. Cardiac transplantation seems to have attained its maturity. The annual number of transplant operations is stagnant and the results progress little. Functional rehabilitation is excellent, the essential immunosuppression which has not changed in principle over the last 12 years, remains prejudicial. Cardiomyoplasty is an attractive concept with difficult surgical indications (Stage III, moderately dilated cardiomyopathy with good right ventricular function without arrhythmias, pulmonary hypertension or mitral regurgitation), a delayed efficacy, a hospital mortality comparable with that of transplantation and a similar survival rate. The objective results are not as good as the more subjective functional improvement. This limited experience (about 500 patients in 50 centers throughout the world, 70% of whom are European) should be continued and evaluated in the centers which initiated it. The artificial heart is only a temporary though essential therapeutic option in certain extremely urgent situations. It is a form of circulatory assistance, ranging from the simple univentricular accessory pump to the univentricular (Novacor) or biventricular (Jarvik) heart, in a rapidly evolving technology with problems of energy sources, marketing, cost and also clinical management which is often difficult especially with respect to coagulation. What do the next ten years hold in store for us? A nex immunosuppressor or the xenograft? A more efficient cardiomyoplasty with more precise medications? A totally implantable autonomous artificial heart? Can economic considerations accompany this development? This is undoubtedly the deepest source of concern for the future.

Adolescent↗

Right ventricular function early after total or standard orthotopic heart transplantation.

Right ventricular failure after orthotopic heart transplantation (OHT) is classically related to preoperative pulmonary hypertension. However, the role of the enlarged atria in right ventricular dysfunction after OHT remains unclear. For that purpose, the right ventricular function in the first 2 days after OHT was compared in two groups of transplant recipients: 11 patients who underwent standard OHT (group I) and 9 patients who underwent total OHT, which consisted of total excision of both the left and right atria and OHT of an intact donor heart with its atria as well as its ventricle (group II). Right ventricular ejection fraction, cardiac index, and right-sided pressures were recorded at baseline and 4, 8, 12, 24, and 48 hours after OHT using a Swan-Ganz catheter with a rapid-response thermistor. Right ventricular function parameters did not differ between groups; they were characterized by a decrease in right ventricular ejection fraction and an increase in right ventricular end-diastolic volume index whereas cardiac index and right-sided pressures remained normal or slightly increased. Ischemic time (177 +/- 41 minutes in group I versus 178 +/- 39 minutes in group II) and preoperative pulmonary vascular resistance (1.9 +/- 0.7 Wood units in group I versus 3.0 +/- 1.5 Wood units in group II) were not different between groups. These results suggest that the anatomic and physiologic advantages offered by the modified technique of OHT had no clinical relevance in this group of patients with low preoperative pulmonary vascular resistances when compared with a group of patients who underwent transplantation with the standard technique.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

[Use of the omentum in the treatment of chronic thoracic empyema].

Thoracic empyema (development of suppuration in the thoracic cavity, usually after pneumonectomy) remains a serious complication which is difficult to treat. Failure of classical procedures (lavage-drainage) in the treatment of certain forms of pleural empyema (post-pulmonary resections), with or without associated fistula, led the authors to use the pedicled omental flaps filling material for the chronic empyema cavity. They report their experience (6 cases over a period of 4 years) and define the indications. Omentoplasty has a real place, next to myoplasty, in the therapeutic arsenal for chronic empyema due to its detersion capacity, particularly useful in a "septic" context and because of its volume which is usually sufficient in retracted cavities. The existence of an associated bronchial fistula, history of radiotherapy, posterolateral thoracostomy (sectioned latissimus dorsi) are additional reasons to prefer omentoplasty over myoplasty.

Adult↗