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Biomedical subjects

M Mathonnet

Publications and source records attributed to M Mathonnet.

At least 19 recordsLinked to original sources
PubMed2006

Neural stem cell separation from the embryonic avian olfactory epithelium by sedimentation field-flow fractionation.

The aim of the present study was to isolate neural stem cells from a complex tissue: the avian olfactory epithelium; by using sedimentation field flow fractionation (SdFFF). By using "Hyperlayer" elution mode, fraction collection and cell characterization methods, results shows that SdFFF could be a useful cell sorter to isolate an enriched, viable and sterile immature neural cell fraction from which the reconstitution of a complete epithelium was possible. In culture, SdFFF eluted cells first led to a "pseudoplacodal" epithelioid cell type from which derived "floating cells". These cells were then able to generate neurosphere-like structures which were composed of cell having many features of immature cells: undifferentiated, self-renewable and multipotentiality. Such a population might be used as a model to improve our understanding of the mechanisms of olfactory neoneurogenesis.

Animals↗
PubMed2006

[Role of preoperative ultrasonography in the management of thyroid nodules].

Ultrasonography is the evidence-based diagnostic method for thyroid nodules. The account has to specify the technical used, and has to exactly describe the echogenicity of the thyroid, the feature of the nodules (number, size, echostructure, echogenicity, edges), and the presence or absence of lymph nodes. The malignancy criteria of thyroid nodules are: (1) hypoechoic solid nodule, (2) presence of internal microcalicifications, (3) ill-defined-irregular edges or absence or breaking of the peripheral halo. The nodes' criteria of malignancy are: (1) diameter of 1 cm or more, (2) clear hypoechoic pattern or non-homogeneous pattern, with alternating hypoechoic and hyperechoic areas, (3) cystic appearance (4) presence of internal calcifications (5) rounded shape with increased anteroposterior diameter, (6) long/short diameter ratio higher than 0.7, (7) absence of hilum. When these criteria are present, a histological diagnosis has to be performed. They could change the operative procedure in the patients.

Biopsy↗
PubMed2005

[Lymph node dissection in non-medullary differentiated thyroid carcinoma].

Papillary and follicular thyroid carcinomas are the most common form of endocrine carcinomas. Lymph node involvement seems to be a low risk factor for death, but it increases the risk for loco-regional recurrences and distant metastasis. The limits and the key points of the cervical lymph node dissection are described. The sentinel lymph node is used to rarely, so it could limit the lymph dissection. Node-picking has to be avoided. Central lymph node resection is recommended for high-risk patients, as male, patients more than 45 or less than 21 years old, papillary carcinomas greater than 1 cm or follicular carcinoma more than 2 cm in diameter. Lateral lymph node resection is performed when the lymph nodes of the central compartment are involved, more than 3 cm in diameter, and bulked. Prophylactic lymphadenectomy is useless. When thyroid carcinoma is known postoperatively, re-operation depends of the cervical mass and of the results of the radioactive iodine treatment.

Adenocarcinoma, Follicular↗
PubMed2005

[Management of adrenal incidentaloma combined with high blood pressure].

Hypertension (HTA) is a very common disease but its origin is well known only in 1 to 5% of the cases. HTA is present in half of the patients who have an adrenal incidentaloma. Clinical data, hormonal sampling, computed tomography and adrenal scintigraphies are necessary to identify hyperfunctioning adrenal tumors. Adrenalectomy is indicated in case of potential malignant tumors and hyperfunctioning tumors. If HTA seems to be not in relation with the adrenal mass, it is recommended to recognize a congenital enzymatic block in order to ovoid an unnecessary adrenalectomy and to search for a preclinical Cushing's syndrome. The last one is associated with HTA in 91% of the cases, and with a morbid obesity, mellitus diabetes or dyslipidemia in 50% of the cases. The removal of the adrenal mass improves the HTA for half of the patients. If the adrenocortical tumor is nonfunctioning, patients have to be followed during a long time. HTA will be considered as "essential" after a new comprehensive analysis performed 3 years later.

Adrenal Gland Neoplasms↗
PubMed2005

Modulation of Fas-induced apoptosis by p75 neurotrophin receptor in a human neuroblastoma cell line.

Fas and p75 neurotrophin receptors (p75(NTR)) are death receptors that alone induce apoptosis of SH-SY5Y neuroblastoma cell line respectively by Fas ligand or brain-derived neurotrophic factor (BDNF, a p75(NTR) ligand). We report on the modulation of Fas-mediated apoptosis by concomitant p75(NTR) activation. The exposure to both ligands suppressed the apoptotic effect. A co-localisation of Fas and p75(NTR) receptors was evidenced by co-capping and immunoprecipitation assays. Moreover, a caspase-8 inhibitor suppressed the protective effect of the concomitant BDNF and Fas ligand stimulation, suggesting that p75(NTR) and Fas receptors could share common signalling pathways.

Apoptosis↗
PubMed2003

Role of laparoscopy in blunt perforations of the small bowel.

BACKGROUND: The purpose of this study was to determine whether laparoscopy could improve our ability to diagnose and treat perforations of the small bowel. METHODS: From 1985 to 2001, among 250 patients admitted for a blunt abdominal trauma, 195 surgical explorations were performed, comprising 42 laparoscopies. On admission, 108 patients underwent an abdominal ultrasonography (US) and 104 a computed tomography (CT). Thirty-nine patients had a blunt small bowel trauma (BSBT) that was explored and/or treated by laparoscopy (n = 15) or celiotomy (n = 24). We compared the patients who underwent emergency surgery (23) and those who were operated on after a mean delay of 51 h. RESULTS: On admission, for detecting free intraperitoneal fluid with a BSBT, the sensitivity of CT was 93.3% and specificity was 13.6%. Regarding the 23 patients who underwent emergency surgery, 8/20 had positive US and 10/15 had positive CT, whereas the 15 celiotomies and 8 laparoscopies indicated BSBT. Regarding the 16 patients who underwent delayed surgery, 9 patients underwent a celiotomy and 7 a laparoscopy; all BSBTs were diagnosed. In searching for BSBT, the sensitivity and specificity of laparoscopy were both 100%, whereas the sensitivity of CT was 83.3% and specificity was 22.2%. Twenty of 23 patients undergoing emergency surgery had bowel suture repair compared to 3/16 after delayed surgery. In contrast, a resection was necessary in 10/12 patients treated after a delay compared to 2/17 operated in emergency. Five BSBTs were sutured by laparoscopy, whereas 10 required conversion. Laparoscopy avoided celiotomy in 15 cases. There were no deaths and no enterostomy. CONCLUSION: In hemodynamically stable patients with blunt abdominal trauma, laparoscopy safely and effectively identifies small bowel injuries. Early recognition of these injuries and timely surgical treatment offer the best prognosis.

Abdominal Injuries↗
PubMed2003

[Colon cancer in pregnancy].

Colon cancers arise only rarely in the course of a pregnancy. Yet colon obstruction, perforation and metastatic spread seem to occur more frequently in this setting than with the average colon cancer. Perhaps this is due to the immunotolerance which accompanies pregnancy. No case of epidermoid (squamous cell) cancer of the colon has been previously described in a pregnant woman. This conjunction has a catastrophic prognosis: the diagnosis of colon tumor is delayed since symptoms are masked by the pregnancy, and epidermoid colon cancer is a particularly aggressive lesion. A major sub-diaphragmatic surgical procedure can be performed with reasonable safety to mother and fetus. Radiotherapy is contraindicated. Neo-adjuvant chemotherapy can be administered although the risks to the fetus are not well known. During the first trimester, a therapeutic abortion can be proposed to optimise the treatment of the mother. During the second and third trimesters, treatment of the mother exposes the fetus to the risk of malformations or premature delivery; delay in maternal treatment in hopes of prolonging the pregnancy in order to obtain a viable neonate diminish the chances of maternal survival.

Adult↗
PubMed2002

[Spontaneous cholecystocutaneous fistula: natural history of biliary cholecystitis].

Spontaneous cholecystocutaneous fistula is a rare complication of gallbladder empyema without treatment. The incidence has further decreased with the advent of resuscitation and surgical treatment. These fistulas are like a cholecystostomy. The diagnostic is confirmed with a fistulogram which allows visualization of the fistula tract. Traditional treatment has consisted of broad-spectrum antibiotics administration, cholecystectomy and fistula drainage. One-stage treatment is the preferred option. Laparoscopic approach appears feasible even the conversion rate is high.

Acute Disease↗
PubMed2002

Differential responses of olfactory neurons to axotomy at embryonic and postnatal stages.

In the nervous system, apoptosis is a major process during embryonic and postnatal stages. In chick, experimental cell death can be obtained by axotomy. We have compared the responses of olfactory neurons to axotomy at embryonic stage E17 and postnatal stages.Forty-three chicken embryos and 32 young chickens less than 3 weeks old were used. We combined optic microscopy, electronic microscopy, terminal (TdT)-mediated dUTP-nick end labeling (TUNEL) method and gel electrophoresis of genomic DNA to analyze cell death. Cells in synthetic phase were labeled by bromodeoxyuridine injected i.p. and detected by immunohistochemistry. Apoptotic index and 5-bromo-2'-deoxyuridine (BrdU) labeling index were calculated for each stage. The Wilcoxon test was used for statistical analysis. A P value <0.05 was considered significant. Within 3 days following axotomy in E17 chicken embryos, there was no significant increase of apoptosis on the lesion side analyzed 3, 6, 12, 18, 24, 48 or 56 h later. A slight increase of bromodeoxyuridine incorporation appeared at 3 h, was weakly significant at 24 h (P=0.045) and the return to basal rate took place at 48 h. In postnatal stages, an apoptotic wave appeared 12 h after axotomy, reached a maximum at 24 h, and then decreased between 48 h and 72 h. A significant elevation of bromodeoxyuridine incorporation occurred on 48 h with a 24 h delay after the peak of apoptotic death. This differential response to axotomy in embryos and postnatal chickens might be due to a less complete maturation and higher plasticity of embryonic olfactory neurons corresponding to different requirement for survival and differentiation factors. Thus the embryonic or immature neurons would depend more on local epithelial environment and mature or postnatal neurons would require target-derived survival factors and die from apoptosis after their shortage resulting from axotomy.

Aging↗
PubMed2001

Insulin-like growth factor I induced survival of axotomized olfactory neurons in the chick.

Insulin-like growth factor 1 (IGF1) receptor is expressed in avian olfactory neurons and IGF1 in the bulb. To explore the function of IGF1 in olfactory system in the chick, we infused IGF1 at the lesion site 0 and 12 h after olfactory axotomy. The animals were killed 1-3 days later. TdT mediated dUTP nick end labeling method and bromodeoxyuridine incorporation allowed the evaluation of programmed cell death and mitotic activity respectively in the olfactory epithelia of IGF1 treated or untreated lesioned animals and controls. IGF1 treatment suppressed the apoptotic wave, stimulated mitosis which peaked within 24 h (instead of 48 h), to return promptly to normal, and transiently maintained the number of calmodulin related kinase II expressing neurons at normal levels. It reveals a long lasting effect of IGF1 on the survival of lesioned olfactory neurons and transient effects on maintenance of differentiation and mitosis stimulation.

Animals↗
PubMed2001

[The avian peripheral olfactory system: model for study of apoptosis and cellular regeneration].

UNLABELLED: A reliable model, usable in vitro and in vivo, is necessary for analysis of processes engaged during cell death, regeneration and differentiation. The peripheral olfactory system is an attractive model for studying these processes through its dynamic neurogenesis that occurs continually throughout the lifetime. STUDY AIM: The aim of this study was the analysis of these processes on an animal model. MATERIAL AND METHODS: We performed axotomy of the nerve olfactory on young animals and chicken embryos E17. Then we infused IGF-I (insulin-like growth factor-I) in the lesioned site. Death, regeneration and differentiation of cells were studied by immunocytology. RESULTS: After hatching, the section of the olfactory nerve induced a rapid neuronal apoptosis at the 24th hour followed by a wave of mitosis 24 hours later. In prenatal stages, the response to the axotomy was rather similar to a dedifferentiation. In postnatal stages, the IGF-I infusion at the lesioned site had a triple function: survival of mature neurons, maintenance of differentiation and stimulation of mitosis. The neoneurogenesis, which occurred from neuronal stem cells would depend on the maturation and environment of the olfactory neurons protected from apoptosis by IGF-I. CONCLUSION: The avian olfactory epithelium is a good model for analysis of cell death, regeneration and differentiation. The capacity of these neuronal stem cells to dedifferentiate makes then more primitive than the pluripotent cells, closer to totipotent embryonic stem cells.

Animals↗
PubMed2000

[Prosthetic treatment of bilateral inguinal hernias via laparoscopic approach or Stoppa procedure].

AIM OF THE STUDY: The aim of this prospective non-randomized study was to compare Stoppa's technique to laparoscopic approach in totally extraperitoneal repair of bilateral inguinal hernia. PATIENTS AND METHOD: From December 1996 to December 1998, 117 consecutive patients with 234 hernias underwent either Stoppa's technique (74 patients) or a totally extraperitoneal laparoscopic approach (43 patients). Patients were randomized in two groups according to the surgeon to whom they were referred. All patients were reviewed in December 1999. RESULTS: There was no mortality. Complications occurred in 3% of patients after Stoppa's technique (group S) and in 4% of patients in the laparoscopic group (group L). The conversion rate was 7% (3 cases). Postoperative analgesia use, hospital stay, and duration of disability were significantly shorter in group L, the cost was lower, but the operating time was significantly longer than in group S. Recurrence rates were similar in the two groups: 2% in group S, 1.1% in group L. CONCLUSION: The laparoscopic approach appears to be preferable to Stoppa's technique in the treatment of bilateral inguinal hernia.

Adult↗
PubMed2000

Multicentre study of thyroid nodules in patients with Graves' disease.

BACKGROUND: The association of Graves' disease with thyroid nodules and thyroid carcinoma is rarely reported. The incidence seems to be increasing according to recent literature. The aim of this multicentre study was to review patients who had surgery for Graves' disease associated with thyroid nodules, and to evaluate the risk of thyroid carcinoma. METHODS: A retrospective study was made of 557 consecutive patients who underwent operation for Graves' disease between 1991 and 1997 in five endocrine surgery departments. Each patient underwent clinical, biochemical, ultrasonographic and scintigraphic evaluation. None of the patients had had previous radioactive iodine therapy or external irradiation. Surgery consisted of either a subtotal or total thyroidectomy. RESULTS: Nodules were observed before operation in 140 patients (25.1 per cent). Thyroid carcinoma was diagnosed in 21 patients (15.0 per cent), always inside a nodule. The incidence of thyroid carcinoma associated with Graves' disease was 3.8 per cent (21 of 557 patients): 20 papillary and one follicular carcinoma. The carcinoma was multifocal in two patients. Tumour diameter ranged from 2 to 25 mm. A nodule was palpable in four patients. CONCLUSION: This multicentre study of patients having thyroidectomy for Graves' disease showed that 3.8 per cent had a carcinoma; the rate of carcinoma in cold nodules was 15.0 per cent. Surgery should be advised in any patient with Graves' disease and a thyroid nodule; the operation should be total thyroidectomy.

Adolescent↗
PubMed1998

[Postoperative incisional hernias: intra- or extraperitoneal prosthesis implantation?].

STUDY AIM: The aim of this retrospective study concerning the repair of postoperative incisional hernia using Dacron mesh was to compare results according to the extra- or intraperitoneal mesh position in order to assess the respective indications of each option. MATERIALS AND METHODS: From January 1985 to December 1996, 172 patients (mean age: 61.3 years) were operated on using Dacron mesh extraperitoneally (n = 99) or intraperitoneally located (n = 73). For statistical analysis, both groups were compared using Chi square test or Fisher's test. RESULTS: There were no postoperative deaths in the group with extraperitoneal mesh and two postoperative deaths in the group with intraperitoneal mesh. There were no significant differences when results comparing parietal complications (sepsis: 2% vs 2.7%, pain: 9.1% vs 16.9%), secondary intestinal disorders (2% vs 4.2%) and recurrence rate (4% vs 5.6%) were assessed between extraperitoneal and intraperitoneal mesh. Recurrences were related to pareital infection treated by partial removal of the mesh (n = 2) or to the lateral detachment of the mesh (n = 6). CONCLUSIONS: In the group of patients receiving extraperitoneal mesh there were no postoperative deaths and morbidity was low (this technique is generally used in the treatment of large incisional hernia). In the group of patients receiving intraperitoneal mesh, similar parietal and general complications were observed. But the risk of serious complications and postoperative death is higher; this technique must be limited to the most serious incisional hernia and to high risk patients.

Adult↗
PubMedDate not supplied

Cyclo-oxygenase 2 tissue distribution and developmental pattern of expression in the chicken.

1. Cyclo-oxygenase 2 (COX-2) is implicated in multiple physiopathological processes. We have studied its physiological expression during chicken embryogenesis. 2. An original procedure was set to prepare a COX-2 probe from red blood cells. In situ hybridization, reverse transcription-polymerase chain reaction and northern blots, were performed on chick embryos from embryonic day (E) 3 to postnatal day 15. 3. In the mesonephros, the signal detected in mesonephric tubules presented a slow increase from E5 to E9, a plateau up to E12 and then a decrease, while the signal increased in the metanephros and then decreased after hatching. Transient expression of COX-2 mRNA in endothelial cells of the infundibulum of the aorta was also detected between E12 and E17. 4. This enzyme may have important roles in kidney morphogenesis during early embryonic stages and in tubular functions during development and in adult life. In the cardiovascular system, its vasodilatory effect could modulate the vasoconstrictor effect of the systolic pressure between E12 and E17 and contribute to a normal morphogenesis of the arterial tree and heart.

Animals↗