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Biomedical subjects

P Vaysse

Publications and source records attributed to P Vaysse.

At least 19 recordsLinked to original sources

Molecular biology and pharmacology of multiple NPY Y5 receptor species homologs.

NPY is a 36-amino acid peptide which exerts its physiological effects through the activation of a family of G-protein coupled receptors. In vivo and in vitro characterization of the recently cloned rat Y5 receptor suggests that it is a primary mediator of NPY-induced feeding (Gerald et al., Nature 1996;382:168-171). We now report the molecular cloning and pharmacological characterization of the human, dog and mouse homologs of the Y5 receptor. With the exception of a 21 amino acid repeat in the amino terminus of the mouse Y5 receptor, the sequence of the four species homologs appear to be highly conserved, with 88% to 97% amino acid identities between any two species. Similarly, the pharmacological profiles of the four species homologs as determined in porcine 125I-PYY binding assays show a great deal of conservation, with the following rank order of affinity: human or porcine NPY, PYY, [Leu31,Pro34]NPY, NPY(2-36), human PP > human [D-Trp32]NPY > rat PP, C2-NPY. Northern blot analysis reveals that the Y5 receptor is widely distributed in the human brain, with the strongest signals detected in the cortex, putamen and caudate nucleus. The chromosomal localization of the human Y5 receptor, previously shown to be overlapping and in the opposite orientation to the Y1 receptor, is determined to be 4q31, the same locus as previously demonstrated for the human Y1 receptor (Herzog et al., J Biol Chem 1993;268:6703-6707), suggesting that these receptors may be coregulated. These Y5 species homologs along with corresponding animal models may be useful in the search for novel therapeutics in the treatment of obesity and related feeding disorders.

Amino Acid Sequence

Microsurgical anatomy of the internal vertebral venous plexuses.

Few studies have been done about the venous vascularization of the spine since neuroradiologic studies in the 1960s and 70s. The aim of this study was to clarify the topography of the internal vertebral venous plexuses in relation to the posterior longitudinal ligament and the dura. The relationships of the vv. were studied at different levels of the spine. The internal vertebral venous system of seven cadavers was injected with a blue bicomponent silicon rubber. It consisted with an anterior and a posterior venous plexus. At the cervical level, the anterior longitudinal vv. are located in a dehiscence of the periosteal layer, in the lateral part of the spinal canal. At each level, they joined the contralateral one at the midline by a retrocorporeal v. located behind the posterior longitudinal ligament. No vv. were found in the epidural space. There was a major development of the retrocorporeal v. of the axis, but it did not receive any venous drainage from the vertebral body. At the thoracic and lumbar levels, the anterior venous plexuses remain within a dehiscence of the periosteal layer, which is thinner. The retrocorporeal vv. become pre-ligamentous. We did not find any posterior venous plexuses at the cervical level, but they were evident at the thoracic level and became more voluminous and sinusoidal in the lumbar region.

Adult

[Utilization of thermosettable compounds in anatomic research].

The authors described a method of vascular injection with a coloured silicon rubber. The injected material was a biocomponent silicon elastomer, with ambiant temperature room vulcanizing. It was supple, easily dissequable and diffuse well into all small caliber vessels. The soft pressure injection did not cause neither material collection by vessels rupture nor anatomic structure distortion. This material could constitute an excellent alternative to coloured latex injection.

Anatomy

A receptor subtype involved in neuropeptide-Y-induced food intake.

Neuropeptide Y (NPY) is a powerful stimulant of food intake and is proposed to activate a hypothalamic 'feeding' receptor distinct from previously cloned Y-type receptors. This receptor was first suggested to explain a feeding response to NPY and related peptides, including NPY2-36, that differed from their activities at the Y1 receptor. Here we report the expression cloning of a novel Y-type receptor from rat hypothalamus, which we name Y5. The complementary DNA encodes a 456-amino-acid protein with less than 35% overall identity to known Y-type receptors. The messenger RNA is found primarily in the central nervous system, including the paraventricular nucleus of the hypothalamus. The extent to which selected peptides can inhibit adenylate cyclase through the Y5 receptor and stimulate food intake in rats correspond well. Our data support the idea that the Y5 receptor is the postulated 'feeding' receptor, and may provide a new method for the study and treatment of obesity and eating disorders.

Amino Acid Sequence

[3H]5-hydroxytryptamine labels the agonist high affinity state of the cloned rat 5-HT4 receptor.

We have used the cloned rat 5-HT4 receptor, and determined that the single protein product produced is able to bind both [3H]5-HT and [3H]GR113808 ([1-[(2-methyl sulphonyl) amino] ethyl-4-piperidinyl] methyl-1-methyl-1H-indole-3-carboxylate) with high affinity. The affinities of agonists for the [3H]5-HT (agonist)-labelled receptor were significantly higher than for the [3H]GR113808 (antagonist)-labelled receptor. Furthermore, [3H]5-HT binding was reduced by addition of guanyl nucleotides. These results strongly support the hypothesis that the 5-HT4 receptor displays two interconvertible affinity states (high and low) for agonists, characteristic of many G protein coupled receptors. [3H]5-HT, at the concentration employed, therefore labels the agonist high affinity state of the 5-HT4 receptor in systems in which high densities of this receptor are found.

Affinity Labels

Abdominal cystic lymphangioma in children: benign lesions that can have a proliferative course.

Twenty-one pediatric cases of abdominal cystic lymphangioma (CL) treated in the past 20 years are reviewed. To date, this is the largest reported series. CL is a rare congenital malformation that presents either with chronic abdominal distension (and is detected by palpation of a cystic mass) or acutely with bowel obstruction or signs of peritonitis. It is more common among boys and most often occurs in children under 5 years of age. Abdominal ultrasonography is the procedure of choice for establishing the diagnosis. Acute cases with intracystic hemorrhage are more difficult to diagnose. Computed tomography and celioscopy may be useful. With these techniques, a correct diagnosis should be achieved in nearly every case. Enucleation (when feasible) or segmental intestinal resection (when the cyst is intimate to the bowel) is effective treatment. In a few cases the malformation is diffuse, and extensive bowel resection is necessary, with the risk of short bowel syndrome.

Abdominal Neoplasms

[Retro-iliac ureter. Report of a case lumbosacral agenesis].

The authors report a case of retro-iliac ureter associated with a lumbo-sacral agenesis. Retro-iliac ureter seems in relation with abnormal constitution of aortic division and/or ilio-cava confluence when the metanephros migrates. Lumbosacral agenesis is the most severe state of sacral agenesis and is a part of the syndrome of caudal regression. The association of the two malformations have never been described and could be fortuitous. Nevertheless, the vertebral malformation could induce a perturbation in the formation of vascular structures and so an abnormal migration of the metanephros.

Adult

Contribution to the study of the tributaries and the termination of the external jugular vein.

The dissection of 100 external jugular veins in 50 cadavers was the object of this anatomic study. A certain number of notions concerning the afferent veins, the mode of termination and the valvular system of this vessel were defined. 1) Afferent veins. Along its pathway toward the deep venous system, the external jugular vein successively received: the transverse cervical vein in 88 cases (88%), usually opposite the intersection of the external jugular vein with the dorsal border of the sterno- cleidomastoid muscle; the suprascapular vein in 47 cases (47%); the anterior jugular vein in 46 cases (46%); the cervical vein or anastomosis with the latter in 13 cases (13%). 2) Mode of termination. Forty-three subjects presented a symmetric mechanism. 100 anastomoses can be classed into three types: in 60 cases (60%), the external jugular vein flowed into the jugulo-subclavian venous confluence; in 36 cases (36%), in to the subclavian vein at a distance from its junction with the internal jugular vein; in 4 cases (4%) in to the trunk of the internal jugular vein. 3) Study of the valves. There were studied in 25 subjects (50 external jugular veins). The valves were found in the ostial and paraostial position in 49 out of 50 veins.

Humans

Laparoscopy and impalpable testis--a prospective multicentric study (232 cases). GECI. Groupe d'Etude en Coeliochirurgie Infantile.

The value of laparoscopy in managing the impalpable testis remains controversial. Several reports have been published on this topic but series are usually short and rather heterogeneous in their presentation, so that critical analysis is not easy to perform. Therefore, the Groupe d'Etude en Coeliochirurgie Infantile started a multicentric prospective study in May 1991 with two objectives: what are the laparoscopic findings and what are the correlations between laparoscopy and surgery? In addition, this study tried to estimate the therapeutic implications. Two hundred and one boys underwent laparoscopy accounting for two hundred and thirty-two impalpable testis. Laparoscopic findings were mainly of three types: intra-abdominal testis (36%), abdominal blind ending cord structures (14%) and cord structures entering the deep inguinal ring (49%); rarely, there was absence of testis and cord structures (1%). Crossed testicular ectopia was not found in this series. One hundred and eighty-seven impalpable testis were operated on to control laparoscopic findings and correlations laparoscopy-surgery were excellent provided that laparoscopic exploration could be entirely performed in good conditions. Moreover, it could be evaluated that forty-seven per cent of impalpable testes could take advantage of laparoscopy.

Adolescent

Cloning of a novel human serotonin receptor (5-HT7) positively linked to adenylate cyclase.

An intron-containing gene encoding a novel human serotonin (5-HT) receptor was isolated from human genomic and cDNA libraries with probes directed to transmembrane regions of the adenylate cyclase stimulatory Drosophila serotonin receptor gene, 5-HTdrol. Membranes harvested from transiently transfected Cos-7 cells displayed high affinity (Kd = 8.5 nM), saturable (Bmax = 6.6 pmol/mg protein) [3H]5-HT binding. The rank order of potencies for serotonergic ligands to displace specific [3H]5-HT binding was: 5-carboxamido-tryptamine > methiothepin > metergoline > 5-HT > 8-hydroxy-2-(di-n-propylamino)tetralin > sumatriptan > ketanserin > zacopride. 5-HT produced a dose-dependent (EC50 = 992 nM) stimulation (approximately 20-fold) of cAMP accumulation in transiently transfected cells, and this response was antagonized by the nonselective 5-HT antagonist methiothepin. RNA for this gene was predominantly detected in the human brain and a subset of peripheral tissues including coronary artery and several tissues of the gastrointestinal tract. The molecular biological and pharmacological properties of this receptor suggest that it is the first member of a new serotonin receptor subfamily (5-HT7). The second messenger coupling, and tissue distribution indicate a possible identity to 5-HT receptors that mediate relaxant responses in certain isolated blood vessels.

Adenylyl Cyclases

[Malignant neonatal tumors].

Malignant neonatal tumors are rare (2% of childhood cancers, 1-2 cases/30,000 births). However, specificities in diagnosis and therapy must be underlined at this period of life; furthermore, the possibilities of antenatal sonographic diagnosis are improving and it may contribute to increase their incidence. Topographic analysis allows etiologic investigations since these tumors have the same diagnostic features as compared with older children, except Pepper's syndrome and leukemias. Therapeutic management depends on a rather good prognosis and fragility of such newborn. Indeed, surgical excision is the main step of treatment. Radiotherapy must be avoided whenever possible. Chemotherapy may be indicated (metastatic or unresectable tumors, omission or delay of irradiation in brain tumors) and has to be elaborated cautiously, according to the peculiar physiology of the neonate. Whatever the therapeutic strategy is, neonatal homeostasis must be well balanced, which implies a multidisciplinary specialized team. Respecting these conditions will help to cure more than the present 50% and better for future well being of such children.

Abdominal Neoplasms

Anatomic basis for use of a gracilis muscle flap.

The aim of this study was to specify certain anatomic features of the gracilis m. with a view to the use of muscular or myocutaneous flaps. It was based on dissection of 84 gracilis muscles in 42 subjects as well as selective injection of the main pedicle of 20 muscles. This established the following points: 1) The arterial supply is abundant, consisting of several pedicles reaching the muscle on its deep aspect. The main neurovascular pedicle arises from the deep vessels of the thigh, via either the a. of the adductors (73%), the medial circumflex a. (19.2%) or as a double supply from both arteries (7.7%); 2) The cutaneous vascularisation over the gracilis m., derived from the solitary main pedicle, is inconstant. In 20 injections, it was satisfactory in 11 cases, poor in 5 and absent in 4; 3) The distal tendon of the gracilis m. is closely related to the posterior branch of the saphenous n. to the leg, which it crosses in an elongated X; 4) A simple method of calculation based on the distance between the upper border of the pubis and the medial femoral epicondyle allows quite precise determination of the point of entry of the main pedicle into the gracilis m. 5) Complete dissection of the main pedicle adds to the available length of the muscle flap.

Humans

Increase in testicular temperature in case of cryptorchidism in boys.

Temperature of the undescended testis, measured in its cryptorchid location during surgical procedure for orchidopexy in 46 boys, 13- to 180-months-old, was significantly higher (34.4 +/- 0.9 degrees C) than that of the contralateral normally descended testicle (33.2 +/- 1.2 degrees C; P < 0.001). Temperature significantly declined from the Bogros' space (35.3 +/- 0.5 degrees C) to the inguinal canal (34.7 +/- 0.7 degrees C) and from the latter to the empty scrotal cavity (31.1 +/- 1.8 degrees C). The physiological descent of the testicle is associated with a marked cooling of its thermal environment. When this process is interrupted for any reason, temperature of the cryptorchid testis is significantly increased. This rise in temperature could be either a concomitant or a main factor for the impairement of testicular functions associated with cryptorchidism.

Body Temperature

[Gracilis muscle in man].

This study is based upon the dissection of 84 gracilis muscles in 42 cadavers. It allowed to emphasize the following features: 1-The proximal insertion of the muscle is a strong tendinous lamina arising from the anterior aspect of the pubis and from the ischio-pubic branch; the distal insertion to the tibia is common to both the gracilis and the semi-tendinous muscles. 2-The distal tendon of the gracilis is tightly connected to the posterior branch of the internal saphenous nerve which crosses the muscle behind the medial femoral condyle. 3-The arterial supply (52 dissections) appears to be very rich, consisting in various pedicles entering the muscle by is lateral side. The main neurovascular bundle is issued from the profound vessels of the thigh, coming either from the adductors artery (73%), either from the medial circumflex artery (19.2%), either from both networks (7.7%). The site of penetration of the vessels in the muscle is remarkably constant. The remaining pedicles (2 to 4, one of which is quite constant at the musculotendinous junction) arise from the muscular branches of the femoral artery. 4-There is a good correlation between the measured length of the muscle and the distance between the superior aspect of the pubic arch and the medial epicondyle. A 0.37 corrective factor applied to this latter distance allows to determine the exact sit of penetration of the main neurovascular bundle in the muscle.

Arteries

Pyloric obstruction with complicated pancreatic heterotopia.

A case of pyloric obstruction associated with pancreatic heterotopia is described in an 18-day old child. The association of several pathologic processes like acute pancreatitis and abscess formation in the heterotopic mass and the long-term follow-up are the main points of interest in this report.

Choristoma

[Non-palpable testes. Apropos of 161 cases].

A series of 161 boys with 178 impalpable testes is reviewed. Extended inguinal exploration was the main form of investigation and treatment. Hormone injections and studies were performed in bilateral cases. Sonography was unhelpful. Laparoscopy was not used. Impalpables testes account for 7% of all boys with an anomaly of testicular descent and 8.5% of operated boys. One hundred and twenty six testes were found, 58 in the abdomen, 68 in the inguinal canal. Thirty one nodular vestige were found and all 25 with histopathology were spermatic duct residue. In 21 boys no trace of testes or spermatic duct remnant were found. Ninety five testes were successfully brought to the scrotum with one (85) or two (10) stage procedure. Anomalies of the upper urinary tract in 13 of 21 cases without testes or spermatic duct remnant were very rare. In bilateral cases it looks better to search a testes whatever the biological responses to gonadotropin stimulation.

Abdomen