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Biomedical subjects

P Clerc

Publications and source records attributed to P Clerc.

At least 37 records · Page 2Linked to original sources
PubMed1996

A 94 kb genomic sequence 3' to the murine Xist gene reveals an AT rich region containing a new testis specific gene Tsx.

X chromosome inactivation in both mouse and human requires the presence of a cis acting locus, the X inactivation centre. This locus is thought to be involved in the initiation and spreading of the inactivation signal in early development. In order to increase our understanding of the mouse X inactivation centre, a 94 kb region immediately distal to the Xist gene has been sequenced and analysed for the presence of transcription units and/or potential cis acting regulatory elements. We have identified a novel gene, Tsx, lying 40 kb 3' from Xist. Tsx is expressed specifically in the testis and shows no convincing homology to proteins currently in the databases. A rat homologue, also X linked, has been isolated. The mouse and rat Tsx sequences are highly divergent, suggesting that part of the X inactivation centre, including both Xist and Tsx are subject to relatively weak evolutionary constraints.

Animals↗
PubMed1995

Identification of a region of the N-terminal of the human CCKA receptor essential for the high affinity interaction with agonist CCK.

The discovery of an N-terminally truncated isoform of the cholecystokinin A subtype (CCKA) receptor exhibiting an atypical pharmacology led us to study the effects of N-terminal truncation on the pharmacology of the human CCKA receptor. We cloned the cDNA encoding the full CCKA receptor and constructed two truncated forms, one which lacked the first 37 amino acids (CCKAT38) and another which lacked the first 42 amino acids (CCKAT43). Expression of the receptors in COS-7 cells showed that the CCKAT38 receptor displayed a pharmacological profile identical to that of the full receptor. In contrast, the CCKAT43 receptor did not directly bind agonist CCK9; however, the agonist could compete for binding at low affinity sites. Binding of the partial agonist JMV180 and the antagonist JMV179 were unaffected. These results identify for the first time a part of the N-terminal, close to the membrane, of the human CCKA receptor that is essential for the high affinity interaction with CCK.

Amino Acid Sequence↗
PubMed1994

Stimulation of tyrosine phosphatase and inhibition of cell proliferation by somatostatin analogues: mediation by human somatostatin receptor subtypes SSTR1 and SSTR2.

The effects of somatostatin analogues RC-160 and SMS-201-995 on tyrosine phosphatase and cell proliferation were investigated in COS-7 and NIH 3T3 cells expressing human somatostatin receptor subtype 1 or 2 (SSTR1 or SSTR2). Binding experiments were performed on membranes from COS-7 cells expressing human SSTR1 or SSTR2 using 125I-labeled [Tyr11]S-14 or [Tyr3]SMS-201-995, respectively. The somatostatin analogues RC-160 and SMS-201-995 exhibited low affinity for SSTR1 (IC50 of 0.43 and 1.5 microM, respectively) and high affinity for SSTR2 (IC50 of 0.27 and 0.19 nM). Addition of these analogues to cells expressing either SSTR1 or SSTR2 did not result in an inhibition of adenylate cyclase activity. In SSTR2-expressing cells, both analogues induced a rapid stimulation of a tyrosine phosphatase activity (EC50: RC-160, 2 pM; SMS-201-995, 6 pM) and an inhibition of serum-stimulated proliferation (EC50: RC-160, 6.3 pM; SMS-201-995, 12 pM). In SSTR1-expressing cells, only RC-160 induced stimulation of a tyrosine phosphatase activity. Both analogues caused an inhibition of cell proliferation at a concentration higher than 10 nM in accordance with their affinities for the SSTR1 receptor subtype. A good correlation between the affinities of RC-160 and SMS-201-995 for each receptor subtype and their potencies to inhibit cell proliferation suggests the involvement of these receptors in cell growth regulation. Tyrosine phosphatase was stimulated by both these analogues in SSTR2 and by RC-160 in SSTR1 at affinities similar to their ability to inhibit growth and bind to receptors, implicating tyrosine phosphatase as a transducer of the growth inhibition signal. We also found that mRNAs of receptor subtypes were variably expressed in different pancreatic and colon cancer cell lines, indicating the necessity of a precise analysis of receptor subtypes in target tissues before therapy with analogues.

3T3 Cells↗
PubMed1994

Chromosomal localization of mouse and human neurotensin receptor genes.

Neurotensin is a tridecapeptide that plays several neurotransmitter or neuromodulatory roles both in the central nervous system and in the periphery. These actions are mediated by a high-affinity receptor (Ntsr). Both rat and human cDNAs encoding high-affinity receptors have been recently cloned. The availability of Ntsr probes allowed us to localize the corresponding genes on the mouse and human chromosomes. The present data demonstrate that the Ntsr gene is assigned to the H region of the mouse Chromosome (Chr) 2 and to the long arm of the human Chr 20.

Animals↗
PubMed1994

[Calcified constrictive pericarditis in an adolescent].

The authors report the case of an adolescent with no previous medical history with calcific pericarditis which rapidly progressed to constriction. The disease was diagnosed several months after an episode of chest pain very suggestive of acute viral pericarditis. Surgery was necessary and resulted in a complete cure of the constrictive pericarditis. The aetiologies of constrictive pericarditis are reviewed; previously, tuberculosis used to be the most common cause but it is being progressively supplanted by other pathologies.

Adolescent↗
PubMed1993

[Migration of an Antheor filter in the pulmonary artery. A case].

Migration of an Antheor caval filter into the pulmonary artery was observed in a 66-year old male patient referred for multifocal pulmonary embolism in a context of heparin-induced thrombocytopenia. The inferior vena cava was of small diameter (18 mm). The filter was removed under cardio-pulmonary bypass and total heparinization, despite the proven thrombocytopenia. The postoperative period was marked by tamponade which had to be drained. The long-term results were satisfactory. This seems to be the first documented case of Antheor caval filter migration into the cardiac cavities.

Aged↗
PubMed1993

[Technical modification of transaxillary resection of the first rib in surgery of thoraco-brachial outlet syndromes].

From April 1985 to September 1991, 88 patients were operated for a total of 100 thoracobrachial outlet syndromes. The patients were placed in the dorsal supine position, turned 30 degrees towards the contralateral side. The arm was suspended in slight abduction. The access obtained is identical to that obtained with the classical operation. No direct traction or compression is exerted on the pedicles during retraction and the operation requires a single assistant. The composition, indications and results of our series are similar to those reported in the recent literature. We did not observed any immediate or late neurological complications. We conclude that thoracobrachial outlet syndromes can be treated via an axillary approach using mechanical traction and a single assistant without increasing the risk of neurological complications.

Adult↗
PubMed1992

Decreased expression of transforming growth factor alpha during differentiation of human pancreatic cancer cells.

The relationship between cell differentiation and transforming growth factor alpha (TGF-alpha) expression in human pancreatic cancer cells was analyzed in Capan 1 cells. These cells differentiate either spontaneously or after butyrate treatment. During differentiation (spontaneous or butyrate induced), TGF-alpha messenger RNA (mRNA) levels decreased, whereas the TGF-beta 1 mRNA levels remained unchanged. TGF-alpha was present in cells as proTGF-alpha, which decreased after butyrate treatment. Secretion of TGF-alpha was not found. Under the two conditions of differentiation, the membrane-bound protein kinase C activity was also reduced. Conversely, long-term phorbol ester treatment increased both membrane-bound protein kinase C activity (260%) and TGF-alpha mRNA level (500%), a not significant increase of TGF-beta 1 mRNA was observed. However, phorbol 12-myristate-13-acetate did not induce TGF-alpha synthesis or secretion. These data suggest that expression of TGF-alpha can be reduced in cancer cells; they also suggest the existence of a relationship between TGF-alpha expression and cell differentiation. In addition, the protein kinase C-induced TGF-alpha mRNA level was not followed by the increase of TGF-alpha biosynthesis, suggesting a translational control. Finally, the expression of TGF-alpha and -beta 1 messengers appears to be differently regulated.

Butyrates↗
PubMed1992

[Cardiac compression by a large thymic cyst. Apropos of a case, review of the literature].

Thymic cysts are rare and almost always asymptomatic. The authors report the case of a 45 year old woman with a thymic cyst diagnosed after recurrent right sided heart failure resulting in signs suggestive of adiastole, regressing after "pleural" (mainly cystic) aspiration and diuretic therapy without any morphological or functional changes on Doppler echocardiography. This report concerns a rare tumour, with an exceptional volume (2 litres) extending down the cardiac borders and causing cardiac compression. It illustrates the diagnostic difficulty of a pathology with an unusual clinical presentation, despite complementary investigations including CT scan and MRI, very sensitive in this type of problem. A complete cure was obtained by total surgical ablation.

Adult↗
PubMed1991

Lipid-dependent proliferation of pancreatic cancer cell lines.

Capan 1, a human pancreatic cancer cell line, is routinely grown in 10% fetal calf serum (FCS). In order to characterize the factors needed for its proliferation, FCS was replaced by a synthetic serum (Ultroser G). For Capan 1 proliferation we found that Ultroser G was as efficient as FCS. A subfraction of Ultroser G containing insulin, transferrin, and lipids was found to be responsible for that response since a combination of these compounds reproduced the growth observed with 10% FCS. Lipids stimulated cell proliferation even in the absence of other factors. Other human (MIA PaCa 2, AsPC1, Panc 1) or rat (AR4-2J) pancreatic cancer cell lines tested proliferated in the reconstituted medium containing insulin (100 ng/ml), transferrin (100 micrograms/ml), fatty acid-free albumin (1 mg/ml), and bovine serum lipids (0.7%), as in 10% FCS. Furthermore, the growth of nonpancreatic cell lines (HT29, A431, CREF) was not enhanced by lipids. Lipoproteins were found to be involved in the mitogenic response of pancreatic cells to lipids, whereas phosphatidylcholine and fatty acids were either inefficient or inhibitors (MIA PaCa2 and AR4-2J). Alkaline phosphatase and amylase content, differentiation markers for Capan 1 and AR4-2J cells, respectively, were not modified by the reconstituted medium. These data suggest that lipids, insulin, and transferrin are the essential factors for the proliferation of pancreatic cancer cell lines, reproducing the growth effect of 10% FCS. Moreover, in the absence of most of the seric growth factors, pancreatic cells remained differentiated.

Blood Substitutes↗
PubMed1989

Experience of partial oesophagectomy in surgical treatment of lower and middle thoracic oesophageal cancer. From a follow-up of 366 cases.

Since carcinoma of the oesophagus is considered to be frequently multicentric, total oesophagectomy appears the only radical therapeutical approach. A follow-up of 366 patients who underwent partial oesophagectomy shows that this procedure can be curative as well as palliative and is sometimes the only procedure possible with a reasonable mortality. These patients had an oesophageal carcinoma located between the cardia and the level of the aortic arch (60.5% squamous, 37% adenocarcinoma). Of these, 22% were over 70 years of age. The surgical route was a left thoracotomy in 280 cases (with anastomosis below or above the aortic arch) or a laparotomy and right thoracotomy in 86 cases. The oesophagus was transected as high as possible and replaced by an isoperistaltic tube fashioned from the greater curvature of the stomach. Mediastinal tissues and the lesser curvature with their lymph nodes were removed. The overall operative mortality was 7% (4% in patients less than 70 and 15% over 70). Very few anastomotic fistulae were observed (6 cases) but they were always severe (6 deaths). The middle and long term results show acceptable functional sequelae and a good survival quality. The survival is 57% at 1 year, 30% at 3 years and 23% at 5 years (27% when the excision appeared curative). There was no significant difference in survival for patients whose cancer was in the mid-oesophagus compared to the lower oesophagus. There was no difference in survival in the cell type squamous or adenocarcinoma. Death was mainly due to metastatic lesions and mediastinal lymphatic recurrence.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma↗
PubMed1989

[Lung and heart-lung transplantation in respiratory tract diseases. Evaluation and development of the indications based on our first 15 cases].

Since January 1988, the Bordeaux group has performed 15 transplantations for lung disease: 9 heart-lung transplants, 1 heart + left lung, 1 double lung, 2 right lungs and 2 left lungs. The transplantations were performed for pulmonary emphysema (10 cases), pulmonary artery hypertension (2 cases), cystic fibrosis (1 case), pulmonary fibrosis (2 cases). Cardiopulmonary transplantation was not always performed because of associated heart failure but sometimes because of large intrahilar adenopathy or intractable bronchial infection. Pulmonary transplantation is recommended on the right side in cases of pulmonary fibrosis. One patient died postoperatively (ischaemia of the transplant). Four others died during the 2nd and 3rd months from poorly defined but probably infectious pulmonary syndromes. The tracheobronchial patency of the 10 survivors was 80% or 100% of the predicted value. The respiratory functional result was excellent in the short and intermediate term. Specific difficulties essentially consisted of pleural symphyses, hilar adenopathy, bronchial infection, steroid dependence of certain subjects, the difficulty of identifying the cause and treating lung opacities during the 2nd and 3rd months.

Anastomosis, Surgical↗
PubMed1989

[Treatment of esophagotracheal fistula following intensive care. An experience of 17 cases].

Oesophago-tracheal fistulae secondary to respiratory intensive care have become the commonest type of non-tumoural fistula in adults: 17/26 cases. They complicated a long period of difficult and septic intensive care, after a mean interval of 30 days. The diagnosis was confirmed by bronchoscopy which also provided good assessment of the site and extent of the fistula and the associated tracheal lesions. The severity of this complication is stressed by 5 deaths in the present series (1 toxi-infectious syndrome after 24 hours, 2 abandonments due to a hopeless resuscitation prognosis, 2 cases of oesophago-tracheal reflux which could have been prevented). One should not wait for spontaneous cure (although this did take place in 2 cases). Ideal direct suture (9 cases: 9 cures) requires local conditions favourable for healing and rapid respiratory autonomy. These conditions can be achieved by an active approach to protection against oesophago-tracheal reflux: at least lower oesophageal exclusion (4 cases) by ligation or anti-reflux operation. Oesophageal exclusion followed by oesophago-coloplasty is sometimes the only solution in cases of severe destruction of cervico-mediastinal tissues (2 cases: 1 cure). Five tracheal strictures required an associated resection-anastomosis (5 cures).

Adult↗
PubMed1989

[Value and current role of anterior mediastinotomy in the diagnosis of mediastinal diseases. Apropos of a series of 100 cases].

One hundred anterior mediastinotomies performed between 1981 and 1987 resulted in the diagnosis of 90 malignant mediastino-hilar or anterior mediastinal tumours, 4 benign lymph node diseases and 6 non-specific lesions. This easy to perform biopsy technique was followed by low morbidity (7%) and one death after 48 hours due to major mediastinal compression. Its sensitivity and specificity make it a valuable alternative and, according to the authors, preferable to mediastinoscopy in the diagnosis of tumours of lymph node diseases in the anterior, pulmonary hila, especially on the left side, and anterior mediastinal lymph node chains.

Adolescent↗