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Biomedical subjects

P Petit

Publications and source records attributed to P Petit.

At least 55 records · Page 3Linked to original sources
PubMed2001

[Role of ultrasound in children with emergency gastrointestinal diseases].

Over the last twenty years, ultrasound has progressively become the primary modality used to assess the acute pediatric abdomen. The lack of radiation exposure and the high diagnostic efficacy of US have contributed to broaden the use of US. During his career, any radiologist may be involved in the evaluation of an acute abdomen in a child. He has to be familiar with the sonographic findings and the age-related symptoms which allow diagnosis of intussusception, hypertrophic pyloric stenosis, midgut volvulus, and appendicitis. He also has to be familiar with the findings which help to exclude these diseases. For experienced radiologists the accuracy in detecting appendicitis and intussusception are respectively close to 95% and 100%. In this chapter, we will also discuss the differential diagnoses of the most frequent causes of acute pediatric abdomen and the technical limitations of US. The learning objectives will be

Abdomen, Acute↗
PubMed2001

The ICF syndrome: new case and update.

The ICF syndrome: New case and update: We report the clinical progress in a 5-year-old boy with the < > (ICF) syndrome. Early diagnosis and intervention has led to a good outcome. DNMT3B mutation analysis was negative, supporting genetic heterogeneity in this condition.

Agammaglobulinemia↗
PubMed2000

4-Hydroxyisoleucine: effects of synthetic and natural analogues on insulin secretion.

4-Hydroxyisoleucine, a peculiar amino acid extracted from fenugreek seeds and never found in mammalian tissues, exhibits interesting insulinotropic activity. To investigate the structural requirements for this stimulating effect, the insulinotropic activity of the major isomer (2S,3R,4S) of 4-hydroxyisoleucine, in the presence of 8. 3 mM glucose, was compared to that of (1) its minor isomer (2R,3R, 4S) (2) its lactone form, (3) classical structurally related amino acids, and (4) synthetic monomethylated analogues. In the isolated, ex vivo, perfused rat pancreas, only the major isomer of 4-hydroxyisoleucine (200 microM) potentiated insulin release. On incubated isolated rat islets, the threshold concentration for a significant increase (P<0.05) in insulin release was 200 microM for (2S,3R,4S) 4-hydroxyisoleucine, 500 microM for (2S,4R) and (2S,4S) gamma-hydroxynorvalines as well as (2S,3S) and (2S,3R) gamma-hydroxyvalines, and 1 mM or more for other congeners. In conclusion, the insulinotropic properties of 4-hydroxyisoleucine, in the micromolar range, are seen only in the presence of the linear major isoform; they also require carbon alpha in S-configuration, full methylation and carbon gamma-hydroxylation.

Animals↗
PubMed2000

Time course of oxidative stress after major burns.

OBJECTIVE: To evaluate oxidative stress resulting from major burns in humans. DESIGN: Prospective clinical study with control group. SETTING: Mechanically ventilated adult patients admitted with more than 30% total burn surface area. PATIENTS AND PARTICIPANTS: 20 patients with a mean body surface burned area of 54%. MEASUREMENTS AND RESULTS: The oxidative stress evaluation was based on measurements of trace elements, vitamins, antioxidant enzymatic activity and end-products of lipid peroxidation. During the first 5 days after injury burn patients exhibit a decrease in selenium and antioxidant vitamins (C, beta-carotene, lycopene) and an increase in lipid peroxidation products (TBARS). CONCLUSION: Our results suggest that major burn is associated with oxidative stress during the 5 days after the initial injury, as demonstrated by a simultaneous decrease in antioxidant vitamins and a large increase in TBARS.

Adult↗
PubMed2000

Inhibition of glucose-induced insulin secretion by a peripheral-type benzodiazepine receptor ligand (PK11195).

We have recently shown that benzodiazepines with high affinity for peripheral-type receptors such as 4'-chlordiazepam inhibit insulin secretion in vitro. PK 11195 [1-(2-chlorophenyl)-N-methyl-N-(1-methylpropyl)-3-isoquinoline-carboxami de], a potent and selective ligand for peripheral benzodiazepine binding sites, was also shown to inhibit insulin release from rat pancreatic islets. Both substances have been reported to interact with mitochondrial binding sites. Hence, the present study was performed to investigate the effects of PK 11195 on insulin secretion induced by either a metabolic or a non-metabolic stimulus. In the rat isolated pancreas perfused at a constant pressure with a Krebs-bicarbonate buffer containing a slightly stimulating glucose concentration (8.3 mM), PK 11195 (10(-7)-10(-5) M) induced a progressive and concentration-dependent decrease in insulin secretion. Simultaneously, we recorded the effects on the pancreatic flow rate; in contrast to 4'-chlordiazepam, previously shown to induce vasodilation in the same preparation, PK 11195 was ineffective. The differential effects of these two substances on vascular resistance and insulin secretion may suggest the existence of different subtypes of peripheral benzodiazepine receptors on pancreatic beta-cells and vessels. A metabolic stimulation of insulin secretion was induced by a glucose increment from 4.2 mM to 8.4 mM or by 2 mM alpha-ketoisocaproic acid (KIC), which is directly metabolized in the mitochondria; these stimulations could be reduced by 10(-5) M PK 11195 (P<0.05). In contrast, the drug was ineffective on the insulin secretion induced by 5 mM or 10 mM KCl in the presence of a nonstimulating glucose concentration (4.2 mM). These results suggest that PK 11195 inhibits insulin secretion by interfering with mitochondrial oxidative metabolism.

Animals↗
PubMed2000

Hepatic regenerating nodules: a mimic of recurrent cancer in children.

BACKGROUND: Pseudometastatic lesions of the liver may be discovered incidentally in children previously treated for malignant tumour. OBJECTIVE: To describe the radiological pattern of these lesions and to analyse their pathogenesis. MATERIALS AND METHODS: Nine children, 2-12 years' old at the time of diagnosis, are described in this retrospective multicentre report. The primary tumours were: nephroblastoma (n = 2), neuroblastoma (n = 2), Ewing's tumour/PNET (n = 2), non-Hodgkin's lymphoma (n = 1), and osteosarcoma (n = 2), treated by surgery (8/9), chemotherapy (9/9), intensive chemotherapy and bone-marrow transplantation (5/9), and radiotherapy (7/9). Three children suffered veno-occlusive disease (VOD) during treatment. The hepatic assessment was performed by sonography (8/9), Doppler (7/9), multiphase spiral CT (8/9) and MRI (7/9). RESULTS: Lesions were discovered 15 months to 16 years after completing treatment. CT was the most sensitive modality for diagnosis. Lesions were multiple in eight cases, measured 2-50 mm, and appeared hypervascular on the arterial phase of CT and/or MRI in every case. Metastases were excluded on the basis of histological verification (n = 2) and clinical and radiological follow-up. CONCLUSION: Pseudometastatic hypervascular hepatic nodules can appear after treatment of a malignant tumour in children. The hypothesis of benign regenerative lesions secondary to treatment and/or VOD is considered.

Child↗
PubMed2000

Iatrogenic dissection of the portal vein during TIPS procedure.

Dissection of the portal vein is a rare entity which has been rarely described during transjugular intrahepatic portosystemic shunt (TIPS) procedure. We report three cases of dissection during this procedure and their complications. One dissection was immediately treated with coaxial stents. The two others were complicated either by a thrombus or by a false aneurysm. In the first case a second parallel stent was used to treat this complication. The patient with the portal vein false aneurysm was transplanted 4 days after this diagnosis. Portal vein dissection in TIPS procedure appeared to be less rare than has been reported and must be considered as a potential cause of TIPS dysfunction.

Adult↗
PubMed2000

Radiological follow-up of inverted papilloma.

The aim of this study was to describe cross-sectional imaging features of recurrent papilloma of the nasal fossa and paranasal sinuses and to evaluate the role of MR and CT in the postoperative follow-up of this lesion. Magnetic resonance imaging and CT of ten patients who presented recurrence of inverted papilloma were reviewed and correlated to initial imaging, endoscopy, and surgical reports. Imaging patterns of recurrent inverted papilloma are identical to those of initial tumors and recurrence location is closely related to the site of the former lesion. Magnetic resonance is more efficient than CT for the diagnosis and evaluation of extensions. Magnetic resonance supplies the deficiencies of endoscopy in case of extensions to the frontal sinus or the lateral recess of the antrum, especially if mucosal hyperplasia or sinusitis is associated. Magnetic resonance imaging is the first imaging modality to perform in the follow-up after removal of inverted papilloma.

Adult↗
PubMed2000

Insulinotropic effect of Citrullus colocynthis fruit extracts.

Infusions of Citrullus colocynthis Schrad. (Cucurbitaceae) fruits are traditionally used as antidiabetic medication in Mediterranean countries, but to our knowledge no studies have been undertaken so far to determine the possible mechanisms involved in the antidiabetic properties of the fruit. The present study was designed to investigate whether these fruits possess insulinotropic effects. For this purpose, different extracts of Citrullus colocynthis seed components were obtained: RN II (crude extract), RN VI (hydro-alcoholic extract), RN X (purified extract) and RN XVII (beta-pyrazol-1-ylalanine), the major free amino acid present in the seeds. The insulin secretory effects of these different extracts were evaluated in vitro in the isolated rat pancreas and isolated rat islets in the presence of 8.3 mM glucose. All tested extracts, when perfused for 20 min at 0.1 mg/ml, immediately and significantly stimulated insulin secretion. This effect was transient. In addition, the purified extract (RN X) provoked a clear dose-dependent increase in insulin release from isolated islets. Moreover, a significant and persistant increase in pancreatic flow rate appeared during RN VI, RN X and RN XVII perfusions. In conclusion, our results show that different Citrullus colocynthis seed extracts have an insulinotropic effect which could at least partially account for the antidiabetic activities of these fruits.

Amino Acids↗
PubMed2000

Widely meshed autograft associated with cultured autologous epithelium for the treatment of major burns in children: report of 12 cases.

This is a retrospective study of the combination of widely meshed autograft and autologous cultured keratinocytes. We used this method faced with the lack of allogenic skin, as an alternate to the Cuono method. Twelve children suffering extensive burn injury (deep burns of 60%+/-16 of the total body surface) underwent this grafting procedure. The surgical treatment consisted of an early surgical excision, with an immediate coverage by autografts as much as possible. When cultured epithelium was available, a large mesh autograft was applied and covered with cultured epidermis sheets during the same operative procedure. The rate of take was of 84% (+/- 12). No secondary graft loss was observed. This means of coverage appeared reliable and resistant. On average, this method allowed the epidermization of 30% (+/-9) of the total body surface of the children. The average hospital stay of the children was 64+/-20 days. All the children recovered to lead a normal life. The school delay after rehabilitation is one year. This technique is an alternative to Cuono's method when allografts are missing. The combination of autograft and autologous cultured epidermis sheets appeared more effective than one of these techniques applied alone, as if the suggested coupling induced a synergy.

Adolescent↗
PubMed2000

Severe heart failure secondary to 5-fluorouracil and low-doses of folinic acid: usefulness of an intra-aortic balloon pump.

OBJECTIVES: To report 5-fluorouracil in combination with folinic acid as a cause of severe nonischemic heart failure and to demonstrate the potential usefulness of an intra-aortic balloon pump. DESIGN: Case report. SETTING: An adult, 19-bed medical/surgical intensive care unit of a university hospital. PATIENTS: A patient, who developed severe heart failure secondary to 5-fluorouracil infusion with low-dose folinic acid, which was introduced to treat a rectal cancer, was transferred from a cancer institute to our intensive care unit 4 days after the treatment was initiated. INTERVENTIONS: Electrocardiography, determination of level of cardiac enzymes, echocardiography, radial arterial catheterization, mechanical ventilatory support, continuous venovenous hemodialysis, vasopressors, and secondary intra-aortic balloon pump. MEASUREMENT AND MAIN RESULTS: During shock, the patient's systolic blood pressure progressively decreased to 70 mm Hg, despite inotropic agents and vasopressors. Transesophageal echocardiography showed a calculated left ventricular ejection fraction within 20% with global hypokinesia. Electrocardiography showed sinus tachycardia with only nonspecific ST-T changes. Results of serial determination of levels of cardiac enzymes were not significant for myocardial infarction. Treatment with an intraaortic balloon pump was initiated and resulted in a dramatical improvement within 48 hrs. The patient was gradually weaned from vasopressors and the intra-aortic balloon pump. By the tenth day, echocardiography showed a septoapical hypokinesia with a 50% left ventricular ejection fraction. On the 30th day, the echocardiography was considered normal. CONCLUSION: Intravenous 5-fluorouracil in combination with low doses of folinic acid can induce severe nonischemic heart failure. In such a case, an intra-aortic balloon pump could be useful by providing left ventricular function support when inotropic agents and vasopressors fail to restore normal hemodynamics.

Adenocarcinoma↗
PubMed2000

[Atypical sonographic findings of bacterial colitis].

We report three pediatric cases of infectious colitis that were misinterpreted on US examination as Crohn's disease. These colitis were limited to the left colon and presented with transmural hypoechoic thickening of the wall and homogenous hyperechoic appearance of the surrounding fat.

Abdominal Pain↗
PubMed2000

[CT imaging of pelvic injuries in polytrauma patients].

CT has become a major tool in the management of multiple trauma. Concerning pelvic trauma, visceral and bone injuries can be detected. We review here the different pelvic injuries focusing on CT diagnostic approach.

Fractures, Bone↗
PubMed2000

[Legionella pneumophila: unusual lung and hepatic manifestations].

We report an uncommon presentation of Legionella pneumophila infection following a placentalblood transplantation in an immunodeficient child. The patient presented with lung nodules and liver abscesses. We discuss how a digestive contamination can be suspected.

Autopsy↗
PubMed2000

2-Thioether-5'-O-(1-thiotriphosphate)-adenosine derivatives: new insulin secretagogues acting through P2Y-receptors.

P2-receptors (P2-Rs) represent significant targets for novel drug development. P2-Rs were identified also on pancreatic B cells and are involved in insulin secretion. The aim of our study was to synthesize and evaluate pharmacologically the novel P2Y-R ligands, 2-thioether-5'-O-phosphorothioate adenosine derivatives, as potential insulin secretagogues. An efficient synthesis of these nucleosides and a facile method for separation of the chiral products is described. The enzymatic stability of the compounds towards pig-pancreas NTPDase was evaluated. The rate of hydrolysis of 2-hexylthio-5'-O-(1-thiotriphosphate)-adenosine (2-hexylthio-ATP-alpha-S) isomers by NTPDase was 28% that of ATP. The apparent affinity of the compounds to P2Y1-R was determined by measurement of P2Y-receptor-promoted phospholipase C activity in turkey erythrocyte membranes. 2-RS-ATP-alpha-S derivatives were agonists, stimulating the production of inositol phosphates with K0.5 values in the nM range. 2-RS-AMP-S derivatives were full agonists although 2 orders of magnitude less potent. All the compounds were more potent than ATP. The effect on insulin secretion and pancreatic flow rate was evaluated on isolated and perfused rat pancreas. A high increase, up to 500%, in glucose-induced insulin secretion was due to addition of 2-hexylthio-ATP-alpha-S in the nM concentration range, which represents 100-fold enhancement of activity relative to ATP. 2-Hexylthio-AMP-S was 2.5 orders of magnitude less effective. A high chemical hydrolytic stability was observed for 2-hexylthio-ATP-alpha-S. Hydrolysis of the phosphoester bond, which was the only detectable degrading reaction under the investigation conditions (pH 7.4, 37 degrees C), was slow, with a half-life of 264 hours. Moreover, even at gastric juice conditions (pH 1.4, 37 degrees C), hydrolysis of the terminal phosphate was the only detectable reaction, with a half-life of 17.5 hours. 2-Hexylthio-ATP-alpha-S isomers are enzymatically and chemically stable. These isomers are highly potent and effective insulin secretagogues, increasing, however, pancreatic vascular resistance.

Acid Anhydride Hydrolases↗