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P Petit

Publications and source records attributed to P Petit.

At least 19 recordsLinked to original sources
PubMed1998

De novo 7q36 deletion: breakpoint analysis and types of holoprosencephaly.

We report on a de novo 7q36 deletion in a 3-month-old girl with manifestations of the 7q terminal deletion syndrome. Only minimal findings of holoprosencephaly (HPE) were present since only a partial corpus callosum hypoplasia was seen on a magnetic resonance imaging scan of the brain. Extensive fluorescence in situ hybridization analysis showed that the HPE3 critical gene region, inclusive Sonic hedgehog (SHH), En2 (HOX1), and HTR5A, was deleted. A review of 33 other patients with a de novo terminal 7q deletion and the different types of HPE manifestations within these patients will be presented.

Brain↗
PubMed1998

Vanishing osteosclerotic lesion of the humeral head.

We report on the spontaneous disappearance of a dense round lesion from within the greater tuberosity of the humerus. The patient was treated with oral non-steroidal anti-inflammatory agents for symptoms of subacromial bursitis. Symptoms resolved in 10 days and the lesion had vanished when radiographed 3 months later. We surmise the lesion to represent intraosseous crystal deposition.

Calcinosis↗
PubMed1998

Postoperative follow-up of juvenile nasopharyngeal angiofibromas: assessment by CT scan and MR imaging.

The purpose of this study was to assess the radiological findings after surgical removal of juvenile nasopharyngeal angiofibromas (JNA). The postoperative CT and MRI scans of ten patients were reviewed. The cured group included six patients. The non-controlled group included six patients with eight recurrences. Two patients belonged to both groups as they were also followed and cured after surgery for relapse. Four recurrences were asymptomatic and diagnosed by imaging. The imaging patterns were matched to the patients clinical status and endoscopic findings. In the cured group, non-enhanced residual soft tissue masses were seen in all cases. In the non-controlled group, recurrence was always demonstrated on early postoperative CT or MR as a dramatically enhanced mass. The recurrence was located in the lateral or superior aspect of the nasopharynx (n = 3), deep to the fossa of Rosenmuller (n = 4) or out of the nasopharynx (n = 1). In two cases a remaining enhanced mass disappeared spontaneously on iterated examinations. Because of numerous asymptomatic relapses, a radiological workup is recommended four months after surgery, even in patients with normal endoscopy, to rule out posterolateral or extranasopharyngeal recurrences. Spontaneous evolution of residual masses must be appreciated on iterated imaging examinations.

Adolescent↗
PubMed1998

The hemodynamic effects of pneumoperitoneum during laparoscopic surgery in healthy infants: assessment by continuous esophageal aortic blood flow echo-Doppler.

UNLABELLED: Cardiovascular changes due to pneumoperitoneum during laparoscopic surgery are established in adult patients, but not known in infants. We investigated the hemodynamic effects of laparoscopy during general anesthesia in 12 ASA physical status I infants by using noninvasive continuous esophageal aortic blood flow (ABF) echo-Doppler monitoring. During the laparoscopic procedure, intraabdominal pressure was maintained automatically at 10 mm Hg by a CO2 insufflator, and minute ventilation was adjusted to avoid hypercapnia. Hemodynamic changes were continuously recorded on soft magnetic support and assessed at three time intervals: t0 (after the initiation of anesthesia), t1 (5 min after peritoneal insufflation), and t2 (5 min after exsufflation). The induction of pneumoperitoneum resulted in a significant decrease in ABF and stroke volume, and in a significant increase in systemic vascular resistance, compared with control values: 67% +/- 9% (P < 0.001), 68% +/- 10% (P < 0.001), and 162% +/- 34% (P < 0.001), respectively. These changes were completely reversed after peritoneal exsufflation. Pneumoperitoneum caused no significant changes in mean arterial pressure or in end-tidal CO2 pressure. These findings demonstrate that laparoscopy is associated with hemodynamic changes without clinically deleterious consequences in healthy infants during a short duration of pneumoperitoneum. IMPLICATIONS: The peritoneal insufflation achieved during laparoscopic surgery is associated with cardiovascular impairments (decrease in cardiac performance and increase in vascular resistance). We found that these changes had no clinically deleterious effects in healthy infants.

Aorta↗
PubMed1998

Reimplantation of growth plate chondrocyte cultures in central growth plate defects: Part II. Surgical experimentation in rabbits.

An original and reliable technique to culture growth plate chondrocytes was developed to obtain an abundant amount of mature and functional chondrocytes. Growth plates were provided from the epiphysis of 3-week-old rabbits. Isolation of the chondrocytes was optimized by the use of trypsin and collagenase. The culture was realized according to the following conditions: seeding at 20,000 or 30,000/cm2 on type I collagen substrate and in Ham F-12 medium without a supplementation of glucose or growth factors. After 7 days of culture, the implantation was to be carried out. Different implantation substrates were evaluated in vivo. Agar turned out to be the only substrate to provide strong and healthy chondrocytes 21 days after the grafting. Then implantation was tested on large iliac resections in rabbits to check whether an enchondral ossification occurred with the culture. Poor results were obtained because of an early disappearance of the cultured chondrocytes. In an other experimentation, the culture was implanted into surgically created defects in the growth plate area. In this case, the culture did produce an epiphysiodesis. However, the 6-week postoperative histological examination showed that the implant remained viable, continued to maintain a proteoglycanrich matrix, and began to organize in ordered columns of mature chondrocytes.

Animals↗
PubMed1998

Myocardial effects of isoflurane in healthy infants and small children. Assessment by continuous oesophageal aortic blood flow echo-Doppler.

BACKGROUND: In paediatric healthy patients and in real peroperative conditions, the cardiovascular effects of isoflurane have been poorly described. METHODS: We have evaluated the myocardial effects of 1% end-expired concentration (EEC) of isoflurane in 25 healthy infants or small children undergoing superficial surgical therapy for small burns with a continuous aortic blood flow echo-Doppler device. Aortic blood flow (ABF) was measured with a small oesophageal probe specially designed for infants. The aortic flowmeter was connected with satellite devices to visualize the haemodynamic profile variations during the isoflurane inhalation period. RESULTS: Isoflurane significantly decreased ABF and increased pre-ejection period/left ventricular ejection time (PEP/LVET), when compared with control values previously recorded 5 min after induction with halothane-fentanyl and atracurium (respectively, 80 +/- 7%, mean +/- SD; P < 0.001 and 111 +/- 11%; P = 0.017, 5 min after EEC of isoflurane reached 1%, then respectively, 75 +/- 12%; P < 0.001 and 119 +/- 16%; P < 0.001, at the end of the isoflurane inhalation period). These variations reversed to a great extent when isoflurane was switched off (97 +/- 17% for ABF; P = 0.08 and 105 +/- 12% for PEP/LVET; P = 0.75). Among the usual parameters, 1% EEC of isoflurane caused no significant changes in heart rate, moderately decreased mean arterial pressure (successively, 88 +/- 12%; P = 0.045 and 87 +/- 19%; P = 0.049), but belatedly decreased end-tidal CO2 pressure (87 +/- 11% at the end of the inhalation period (P < 0.001) which persisted 5 min after isoflurane was turned off (90 +/- 11%; P < 0.001)). CONCLUSIONS: These findings suggest that isoflurane can transiently depress cardiac function in healthy infants.

Anesthetics, Inhalation↗
PubMed1998

4-Hydroxyisoleucine: a novel amino acid potentiator of insulin secretion.

We report the characterization of a new insulinotropic compound, 4-hydroxyisoleucine. This amino acid has been extracted and purified from fenugreek seeds, which are known in traditional medicine for their antidiabetic properties. 4-Hydroxyisoleucine increases glucose-induced insulin release, in the concentration range of 100 micromol/l to 1 mmol/l, through a direct effect on isolated islets of Langerhans from both rats and humans. The stimulating effect of 4-hydroxyisoleucine was strictly glucose dependent; indeed, ineffective at low (3 mmol/l) or basal (5 mmol/l) glucose concentrations, the amino acid potentiated the insulin secretion induced by supranormal (6.6-16.7 mmol/l) concentrations of glucose. In addition, in the isolated perfused rat pancreas, we could show 1) that the pattern of insulin secretion induced by 4-hydroxyisoleucine was biphasic, 2) that this effect occurred in the absence of any change in pancreatic alpha- and delta-cell activity, and 3) that the more glucose concentration was increased, the more insulin response was amplified. Moreover, 4-hydroxyisoleucine did not interact with other agonists of insulin secretion (leucine, arginine, tolbutamide, glyceraldehyde). Therefore, we conclude that 4-hydroxyisoleucine insulinotropic activity might, at least in part, account for fenugreek seeds' antidiabetic properties. This secretagogue may be considered as a novel drug with potential interest for the treatment of NIDDM.

Animals↗
PubMed1998

Unusual de novo t(13;15)(q12.1;p13) translocation leading to complex mosaicism including jumping translocation.

We report on a patient with neurosensory deafness, cataract and moderate mental retardation showing a constitutional mosaicism with the predominant cell line consisting of a 45,XY,-13,-15,+t(13;15) translocation of the Robertsonian type. By means of fluorescence in situ hybridization (FISH) using a panel of acrocentric pericentromeric probes and various banding techniques, the breakpoints in the translocation were determined at 13q12.1 and 15p13 respectively. Five other cell lines were present, at low percentage, one of them showing a t(13;15) tandem translocation. Interstitial telomeric sequences could be detected at the translocation fusion sites in both the Robertsonian and tandem translocations. The mosaicism appears therefore to be a consequence of chromosomal instability involving the t(13;15) fusion region of the predominant cell line, and related to the presence of interstitial telomeric sequences. The present observation suggests that in the pericentromeric 13q12 region, a gene involved in neurosensory deafness may be located.

Cataract↗
PubMed1997

Continuous oesophageal aortic blood flow echo-Doppler measurement during general anaesthesia in infants.

PURPOSE: Invasive haemodynamic monitoring during general anaesthesia in infants is usually limited to very high risk operations, such as cardiac surgery. Nevertheless, different surgical procedures and/or anaesthetic techniques justify additional monitoring for children, as for adults. The aim of this preliminary study was to evaluate the feasibility of using a new echo-Doppler device (Dynemo 3000) capable of measuring continuous aortic blood flow during general anaesthesia in infants. METHODS: Aortic blood flow (ABF) was measured with a small oesophageal probe designed for newborns and infants. The aortic flowmeter was connected with satellite devices to visualise the haemodynamic profile which included ABF, pre-ejection period (PEPi), left ventricular ejection time (LVETi), mean arterial pressure, heart rate, stroke volume and systemic vascular resistance. Twelve infants, aged 8-26 mo, undergoing surgery under general anaesthesia were successively included in the evaluation of this device. Isoflurane (1% end-expired concentration) was introduced to maintain anaesthesia after induction with halothane, midazolam, fentanyl and atracurium. RESULTS: Correct positioning of the probe was easily obtained in all cases and the recording quality was excellent, whatever the operative position. Recordings of haemodynamic data showed some myocardial depression from isoflurane: decreased ABF (indexed to body surface area) and lengthened PEP/LVET (2.24 +/- 0.53 L.min-1.m-2 and 0.32 +/- 0.05 respectively, before introduction of isoflurane and 1.71 +/ 0.53 L.min-1.m-2 (P = 0.027) and 0.39 +/- 0.06 (P = 0.007) with isoflurane). CONCLUSION: These preliminary results suggest that this continuous ABF echo-Doppler device may be valuable for peri anaesthetic monitoring in infants.

Anesthesia, General↗
PubMed1997

Imaging of vascularized fibular grafts in large bone reconstruction in skeletally immature patients.

OBJECTIVE: To describe the imaging findings of vascularized fibular grafts (VFG) in large bone reconstruction in children and teenagers. DESIGN AND PATIENTS: Fifteen patients aged from 4 to 19 years underwent VFG for bone reconstruction for primary tumors involving bone in 13 cases and for chronic osteomyelitis in 2 cases. Lesions were located in the femur (6 cases), the tibia (6 cases), the humerus, the distal fibula and the ilium. Radiographic follow-up was performed in all patients, radionuclide studies in 12 patients and MRI in 8. RESULTS: Plain films showed a lamellated periosteal reaction on the VFG within 3 weeks following the procedure in all cases. Fusion of VFG and host bone occurred during the first 3 months. Radionuclide uptake of the VFG was seen in all cases but one. MRI showed cortical thickening and conservation of the high signal intensity of fatty marrow on T1-weighted sequences, and periosteal enhancement on dynamic post-contrast studies in all but one of the patients. CONCLUSION: Radionuclide studies and MRI show the periosteal enhancement and assess the viability of the VFG satisfactorily. However, we feel that plain films may be sufficient to ascertain this viability.

Adolescent↗
PubMed1997

Interstitial telomeric sequences at the junction site of a jumping translocation.

The mechanism(s) for the origin of jumping translocations (JTs) are unknown. To assess the possible involvement of telomeric sequences in the jumping process, metaphases of a patient with hydrops fetalis having a JT were analyzed for the presence of interstitial telomeres. Telomere DNA sequences were detected at the junction sites of the donor and the recipient chromosomes. Interstitial telomeric sequences have so far only been detected in JTs involving chromosome 15q in patients with Prader-Willi syndrome. Our finding of interstitial telomeric sequences in a JT with a chromosome different from chromosome arm 15q in a patient without Prader-Willi syndrome implies that telomere sequences may be common to all telomeric JTs. The possible role of telomeric sequences as a cause of the observed chromosomal mosaicism is discussed.

Chromosomes, Human, Pair 4↗
PubMed1997

In the early stage of major burns, is there a correlation between survival, interleukin-6 levels and oxygen delivery and consumption?

The correlation between haemodynamic and oxymetric parameters, and circulating cytokines has been little studied for the early phase of extensive burns. The aim of this prospective study was to evaluate survival, looking at variations in cardiac index (CI), oxygen delivery (DO2I) and consumption (VO2I) indexed to the body surface area (BSA), and circulating interleukin-6 (IL6) levels in the acute stage of major burns. Over a 12-month period, all patients admitted within 6 h of extensive thermal injury with total burn surface area (TBSA) of over 60 per cent, necessitating standardized resuscitation and mechanical ventilation, were included. Routine intensive care monitoring, including pulmonary and femoral artery catheters, was set up. During the first 3 days post-injury haemodynamic and oxymetric profiles were recorded every 6 h. Circulating IL6 samples were taken within 6 h of admission, then daily (at 24, 48 and 72 h). A comparison of the results in survivors (S) and non-survivors (NS) at those previously determined times was made. Ten consecutive patients were studied. Six patients survived (Age = 33 +/- 10 years; TBSA = 76 +/- 11 per cent) and four died (Age = 40 +/- 14 years; TBSA = 77 +/- 13 per cent). Similar initial hypovolemic profiles were found in both groups. From 24 h, a hyperdynamic status was observed which increased until 72 h. This hyperkinetic evolution was more marked in the survivors (CI: 4.6 +/- 2.0 for NS and 6.9 +/- 1.51 min-1 m-2 for S; SVRI: 2125 +/- 1288 for NS and 918 +/- 232 dyne s cm-5 m2 for S at 72 h). DO2I and VO2I were always higher in the survivors. DO2I and VO2I increased from admission to 72 h in the survivors whereas a significant drop in DO2I and VO2I occurred in the non-survivors at 48 h (DO2I:536 +/- 222 for NS and 1228 +/- 268 ml min-1 m-2 for S; VO2I:120 +/- 50 for NS and 251 +/- 56 ml min-1 m-2 for S (P < 0.01)). Plasma IL6 revealed abnormal values with consistent peaks at 24-48 h in the survivors (respectively 17,411 +/- 24,542 and 10,746 +/- 11,802 pg ml-1) and only moderate peaks in the non-survivors (865 +/- 652 and 912 +/- 485 pg ml-1). Finally, CI, DO2I, VO2I and circulating IL6 were always higher, and SVRI lower, in the survivors than in the non-survivors. The ability to increase DO2 and to optimize VO2 during the 'turning point' of 48 h seems to improve the prognosis of critically burned patients: the role of IL6 in this systemic inflammatory response is discussed.

Adult↗
PubMed1997

Effects of homocysteine on acetylcholine- and adenosine-induced vasodilatation of pancreatic vascular bed in rats.

1. Epidemiological and experimental data have shown that homocysteine may provoke vascular lesions and that moderate homocysteinaemia may constitute an independent risk factor for vascular disease. It is now documented that homocysteine damages human endothelial cells in culture, possibly by producing hydrogen peroxide in an oxygen-dependent reaction. 2. In this study, we have examined the direct effect of this sulphur amino acid on pancreatic vascular resistance. Experiments were performed on the vascular bed of the rat isolated pancreas perfused at constant pressure; thus, any change in pancreatic vascular resistance resulted in a change in the flow rate. D,L-Homocysteine perfused for one hour at three different concentrations (200 microM, 2 mM, 20 mM) did not induce any significant change in the flow rate per se. Homocysteine infusion for 30 min at a concentration of 200 microM or 2 mM abolished the endothelium-dependent vasodilatation induced by acetylcholine (0.05 microM), but did not modify adenosine (1.5 microM)-induced vasodilatation. 3. The effect of D,L-homocysteine (200 microM or 2 mM) cannot be ascribed to a direct antimuscarinic effect since 30 min pretreatment of rat ileum with these concentrations did not significantly change the contractile effect of increasing concentrations of acetylcholine (0.015-15 microM). 4. Preincubation of human umbilical vein endothelial cells with D,L-homocysteine (0.2-5.0 mM) had no significant effect on overall cell number or viability during 18 h of incubation; the endothelial cells exposed to concentrations up to 5 mM exhibited a spindle-shaped, whirled pattern. This pattern was reversed 48 h after the removal of homocysteine. A cytotoxic effect was seen after 18 h incubation in 10 mM D,L-homocysteine. 5. In conclusion, an acute infusion of homocysteine altered acetylcholine endothelium-induced vasodilation, whereas the adenosine vasodilatator effect was insensitive to the deleterious action of homocysteine in vitro.

Acetylcholine↗
PubMed1997

The IL-9 receptor gene, located in the Xq/Yq pseudoautosomal region, has an autosomal origin, escapes X inactivation and is expressed from the Y.

All human X-linked genes known so far, except for the Xp/Yp pseudoautosomal genes, are conserved as a single linkage group on the murine X chromosome. We show that the interleukin-9 (IL-9) receptor gene (IL9R), which is located within the human Xq/Yq homology region, maps to the murine chromosome 11. The Xq/Yq pseudoautosomal region (Xq PAR) thus represents a second region on the human X chromosome which is not X linked in mice. Furthermore, we show that IL9R is absent on the Y of great apes. IL9R is thus exceptional among X/Y genes in that it is X linked in some mammals, but autosomal or pseudoautosomal in others. Genes located on the X and the Y generally escape X inactivation. An exception to this rule is SYBL1, a gene located in Xq PAR. SYBL1 is X inactivated and is inactive on the Y chromosome. In contrast, we show that IL9R expression does occur from the Y, the active and the inactive X chromosomes. This finding raises the question of how the transcriptional regulation of genes within Xq PAR occurs and how the X inactivation status of IL9R has evolved following the autosome to X and the X to X/Y translocation. The evolutionary analysis of the IL9R gene, which is located at 10 kb from the telomere, and its pseudogenes at several telomeres, also provides insight into the evolution of these loci and of subtelomeric regions in general.

Animals↗
PubMed1997

Comparative effects of adenosine-5'-triphosphate and related analogues on insulin secretion from the rat pancreas.

Adenosine tri- and diphosphate (ATP and ADP) and their structural analogues stimulate insulin secretion from the isolated perfused rat pancreas, an effect mediated by P2Y-purinoceptor activation. Concerning the base moiety of the nucleotide, it was previously shown that purine but not pyrimidine nucleoside triphosphates were active and that substitution on purine C2 with the 2-methylthio group greatly enhanced the potency. In this study, we further analyze the consequences of ribose and polyphosphate chain modifications. Modifications in 2' and 3' position on the ribose led to a decrease in insulin response when bulky substitutions were made: indeed, 2'-deoxy ATP was similar in activity to ATP, whereas arylazido-aminopropionyl ATP (ANAPP3) was weakly effective and trinitrophenyl ATP (TNP-ATP) was inactive. Substitution on the gamma phosphorus of the triphosphate chain led to a decrease (gamma-anilide ATP) or no change (gamma-azido ATP) in potency; the replacement of the bridging oxygen between beta and gamma phosphorus by a peroxide group did not significantly change the activity, whereas substitution by a methylene group completely abolished stimulation of insulin secretion. As for the phosphorothioate analogues, adenosine-5'-O-(3-thiotriphosphate) (ATP gamma S) induced an insulin response similar to that produced by ATP, whereas adenosine-5'-O-(2-thiodiphosphate) (ADP beta S) was about 100-fold more potent than ATP, as previously shown. In conclusion, two structural features seem to have a strategic importance for increasing the insulin secretory activity of ATP analogues: substitution at the C2 position on the adenine ring of ATP and modifications of the polyphosphate chain at the level of the beta phosphorus.

Adenosine Diphosphate↗
PubMed1997

Trisomy 15 rescue with jumping translocation of distal 15q in Prader-Willi syndrome.

We report a patient with Prader-Willi syndrome (PWS) and mosaicism for a de novo jumping translocation of distal chromosome 15q, resulting in partial trisomy for 15q24-qter. A maternal uniparental heterodisomy for chromosome 15 was present in all cells, defining the molecular basis for the PWS in this patient. The translocated distal 15q fragment was of paternal origin and was present as a jumping translocation, involving three different translocation partners, chromosomes 14q, 4q, and 16p. The recipient chromosomes appeared cytogenetically intact and interstitial telomere DNA sequences were present at the breakpoint junctions. This strongly suggests that the initial event leading to the translocation of distal 15q was a non-reciprocal translocation, with fusion between the 15q24 break-point and the telomeres of the recipient chromosomes. These observations are best explained by a partial zygotic trisomy rescue and comprise a previously undescribed mechanism leading to partial trisomy.

Adult↗
PubMed1997

The treatment of sexually dysfunctional men without partners: a controlled study of three behavioural group approaches.

BACKGROUND: Models of sex therapy for sexual dysfunction in single men are available, but their value is not well established. This controlled study compared three approaches to the treatment of sexually dysfunctional single men. METHOD: Sixty-nine single men diagnosed as sexually dysfunctional were randomly assigned to treatments focusing on either their sexual dysfunction, their interpersonal problems, a combination of both or a waiting list; 51 completed treatment and 50 the one-year follow-up. Treatment was administered in small groups in 15 weekly sessions and four six-weekly sessions during the first six months of a year-long follow-up. RESULTS: No clinically meaningful change was observed during the waiting period. In contrast, a significant and equivalent improvement was observed in all treatment groups by the end of treatment. However, differences between them were in evidence at 6 and 12 months' follow-up. CONCLUSIONS: Both treatments paying attention to the patients' interpersonal difficulties resulted in significantly better outcomes overall than the approach that concentrated on problems in sexual functioning alone.

Adult↗