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Biomedical subjects

P Deprez

Publications and source records attributed to P Deprez.

At least 109 records · Page 6Linked to original sources
PubMed1986

The influence of the administration of sow's milk on the post-weaning excretion of hemolytic E. coli in the pig.

The postweaning excretion rate of hemolytic E. coli was determined in piglets from herds affected with edema disease and on control farms. No distinct difference in rate of excretion was observed. A split litter trial was set up to evaluate the importance of sow's milk in the postweaning rise of fecal hemolytic E. coli. 525 ml of sow's milk a day, mixed with the feed, completely inhibited that postweaning rise, even after oral challenge with a pathogenic strain.

Animals↗
PubMed1984

Potassium concentration in equine red blood cells: normal values and correlation with potassium levels in plasma.

The concentration of potassium in plasma and in red blood cells was determined in 948 horses. The coefficient of correlation between the two parameters was low. In 436 of these horses, which were clinically healthy, the red blood cell potassium (RBCK+) levels did not fit within a normal distribution curve, but a bimodal distribution was observed with a section point at 90 mmol/litre. In 90 per cent of these normal horses, mean RBCK+ content was 97.5 mmol/litre. In the remaining 10 per cent, mean RBCK+ concentration was 93.8 mmol/litre. A subdivision into a 'low potassium group' and a 'high potassium group' was made. In 10 out of 15 horses in the 'low potassium group', bimonthly sampling over a period of one year showed that RBCK+ content remained low. In the remaining five horses an increase was observed.

Animals↗
PubMed1984

Determination of red blood cell potassium content in horses with diarrhoea: a practical approach for therapy.

The concentration of potassium in the red blood cells in 15 horses with severe diarrhoea was determined. The red blood cell potassium content (RBCK+) was low compared with levels obtained in normal horses. The decrease in the RBCK+ was used to evaluate the total body potassium deficit. This calculated amount was administered orally, following each RBCK+ determination. In those horses which recovered, RBCK+ content returned to normal levels. During treatment, refilling of the red blood cells with potassium occurred only gradually as long as the diarrhoea persisted. In each case, oral loading with the calculated dose resulted in an improvement of the general condition and no side effects were observed. The importance of using RBCK+ levels as a diagnostic and therapeutic parameter is discussed.

Animals↗
PubMed1980

Esterification of cholesterol and lipid-soluble vitamins by human pancreatic carboxyl ester hydrolase.

Human pancreatic carboxyl ester hydrolase is shown to catalyse the esterification of cholesterol and lipid-soluble vitamins A, E and D3 with oleic acid. The acitivity requires the presence of bile salts, and the trihydroxylated or the 3 alpha, 7 alpha dihydroxylated bile salts are better activators than the 3 alpha, 12 alpha dihydroxylated bile salts. The hydrolyzing and synthetizing activities of human pancreatic carboxyl ester hydrolase are separated by a large pH range since the synthesis of cholesterol esters is optimal at pH 5.25 and the hydrolysis of cholesterol and vitamin E esters is optimal at pH 8.0. From the comparison of the catalytic constants determined for the hydrolyzing and synthetizing activities and from the pH dependence of the two activities, it appears that human carboxyl ester hydrolase plays an important part in the intestinal lumen. The role of the enzyme in the esterification of cholesterol and lipid-soluble vitamins is questionable.

Bile Acids and Salts↗
PubMed1978

The two human trypsinogens: catalytic properties of the corresponding trypsins.

The catalytic properties of the two human trypsins obtained from purified trypsinogens have been studied. The catalytic rate constant kcat and the pK of the ionisable residue implicated in the active site have been determined with Bz-Arg-OEt. The hydrolysis of Tos-Arg-OMe by human trypsins does not follow the simple Michaelis-Menten scheme and indicates a difference in the conformational flexibility of the active site-regions of the two enzymes. Both enzyme are readily autolyzed and calcium ion plays a fundamental role in stabilizing trypsin activity. However trypsin 2 self-digests more rapidly than trypsin 1. These results are a prerequisite to the elucidation of the fate of pancreatic enzymes in human digestive tract.

Animals↗
PubMed1978

[Chédiak-Higashi disease (report on a new case) (author's transl)].

A typical case of Chédiak-Higashi disease is reported in a French four years old boy (no parents consanguinity). The clinical aspect of oculo-cutaneous and pilar hypopigmentation, associated with recurrent infections led to the diagnosis of C. H. disease which was confirmed by the presence of giant leukocytes granulations in the blood and giant melanosomes in epidermal melanocytes; these giant pigmented granules, are made of a limiting unique membrane with granular matrix and periodic filamentous structures, which correspond to stade I, II and III melanosomes. In keratinocytes, melanosomes are rare, never isolated and scattered in cytoplasm, but grouped in giant melanosomes complexes. No specific immunity deficiency is found in this patient but the chemotaxis of neutrophil polymorphonuclear leukocytes was decreased but restored by levamisole treatment. Concanavaline A Cap formation by polymorphonuclear leukocytes was abnormally increased, but returned at a normal level after cyclic GMP incubation and levamisole treatment. Unfortuntely, the patient died soon after accelerated phase had begun, in an anatomo-clinical picture of pseudo-lymphoma. A pathogenic discussion of CH disease is presented with the help of a study of 102 cases of literature.

Chediak-Higashi Syndrome↗
PubMedDate not supplied

Src homology-2 domain binding assays by scintillation proximity and surface plasmon resonance.

Various SH2 competitive binding assays, based on different techniques, have been described in the literature to identify and characterize SH2 ligands. The consideration that most reported methods show experimental limitations associated with assay parameters has prompted us to base our Src-SH2 inhibitor discovery program on the use of two different assays. In this study, two conceptually different biochemical methods designed to discover Src-SH2 inhibitors, respectively scintillation proximity assay (SPA) and surface plasmon resonance (SPR), have been evaluated and compared. For its high sensitivity and adaptability to automation SPA was chosen for high capacity screening (primary screen), whereas SPR was used for hits confirmation (secondary screening). However with the drastic improvement of inhibitor affinities, the limit of sensitivity was rapidly reached for the SPR assay based on the canonical pYEEI ligand. The substitution of the natural, monophosphorylated peptide ligand with a triphosphorylated peptide has allowed us to remarkably increase its sensitivity, so that molecules with nanomolar affinities could be easily differentiated in terms of IC(50) ranking. Such a new, improved SPR assay can be of great interest for the study of high affinity ligands of different SH2-based drug targets.

Binding, Competitive↗
PubMedDate not supplied

Effect of inhaled nitric oxide on the hypoxic pulmonary vasoconstrictor response in anaesthetised calves.

The effect of inhaling nitric oxide in the hypoxic pulmonary vascular response was measured in five calves anaesthetised with a combination of guaiacol, ketamine and xylazine. Alveolar hypoxia was induced by means of the inhalation of a gas mixture with an inspiratory oxygen fraction of 14-18 per cent. This alveolar hypoxia resulted in a pronounced pulmonary hypertension (mean pulmonary artery pressure in hypoxic animals: 30.2 mmHg). Inhalation of 20 and 40 ppm of nitric oxide significantly attenuated the hypoxia induced pulmonary hypertension. The effect ceased once nitric oxide administration was stopped. A concentration of 40 ppm of nitric oxide fully abolished the hypoxia induced pulmonary hypertension (mean pulmonary artery pressure during inhalation of 40 ppm nitric oxide: 22.8 mmHg). Inhalation of nitric oxide had no effect on systemic arterial blood pressure nor on systemic vascular resistance. It was concluded that inhalation of 20 or 40 ppm of nitric oxide prevented a selective pulmonary vasoconstriction during alveolar hypoxia in calves, which may be helpful in the treatment of acute respiratory disorders in calves.

Administration, Inhalation↗
PubMedDate not supplied

Dual-chamber pacemaker implantation via the cephalic vein in healthy equids.

The purpose of the present study was to develop a feasible and safe technique for dual-chamber pacemaker implantation in healthy horses. Implantation was performed in a standing, tranquilized horse and in ponies. Atrial and ventricular leads were transvenously inserted through the cephalic vein, and a subcutaneous pacemaker pocket was created between the lateral pectoral groove and the manubrium sterni in 6 equids. Positioning of each lead was guided by echocardiography and by measuring the electrical characteristics of the lead. The implantation procedure lasted about 4 hours in each animal and was well tolerated. In all animals, dual-chamber pacemaker function was obtained, and these results remained good throughout the follow-up period. At the time of implantation, atrial and ventricular sensing were between 2.1 and 7.2 mV and 7.8 and 16.8 mV, respectively, and atrial and ventricular pacing thresholds at 0.5 millisecond varied from 0.5 to 0.7 V and from 0.3 to 1.0 V, respectively. Six months after the implantation, sensing values varied from 2 to 10 mV for the atrial lead and from 2 to 16 mV for the ventricular lead, while pacing thresholds at 0.5 millisecond varied from less than 0.5 to 2.5 V for the right atrium and from less than 0.5 to 5.0 V for the right ventricle. Atrial lead dislodgment occurred in 2 animals, requiring insertion of a new lead. Ventricular lead dislodgment was not observed.

Animals↗
PubMedDate not supplied

Approach of suspected common bile duct stones: endoscopic ultrasonography.

Recent studies have shown that endoscopic ultrasonography (EUS) is the most sensitive method for diagnosing choledocholithiasis. High sensitivities of more than 95% have been reported by several authors. Imaging the extrahepatic bile ducts and the gallbladder and searching for biliary stones are easy tasks for EUS. EUS has the advantages over ERCP to be less invasive (complication rate similar to diagnostic upper GI endoscopy) and to be able to detect small stones and sludge that can easily be masked by contrast medium during ERCP. In comparison with magnetic resonance imaging (MRI), EUS has the advantage to be close to the investigated areas and to allow the detection of very small stones or sludge, even in non dilated bile ducts. Technical limitations of biliary imaging by EUS are few: upper GI stenosis, previous gastrectomy or Billroth II resection. Imaging can be obscured by the presence of air (previous sphincterotomy or surgical bypass), surgical clips calcifying pancreatitis or a duodenal diverticulum. Main indications of EUS include the detection of choledocholithiasis in patients with a low and intermediate probability of presence of stones, in idiopathic acute pancreatitis, in mild and moderate pancreatitis after normal transabdominal ultrasonography, in pregnant women, in intensive care patients, in the diagnosis of gallbladder lithiasis or sludge, and also when MRI is contraindicated (claustrophobia and metallic implants) or fails to provide a diagnosis or is not available. Screening of choledocholithiasis with EUS has also been proposed in patients scheduled for laparoscopic cholecystectomy, but this is not common practice in Belgium.

Endosonography↗
PubMedDate not supplied

Endoscopic ultrasound guided fine needle aspiration in biliary and pancreatic diseases: pitfalls and performances.

Endoscopic ultrasound guided fine needle aspiration (EUSFNA) has become the most accurate modality for characterization of pancreatic cystic and solid lesions, for differential diagnosis of indeterminate pancreatic masses and for locoregional staging of pancreatic and extrahepatic biliary tumours. EUS-FNA should also be performed in distant lymph nodes, ascites, liver, adrenal and mediastinal metastatic locations. Experienced groups reach a sensitivity over 85% with a 90-100% specificity, a positive predictive value of 98-100%, a negative predictive value of 44-80%, and an accuracy of 75-84% in evaluation of pancreatic masses. Morbidity rate (acute pancreatitis, infection, haemorrhage, perforation) is very low being around 1-2% and risk of peritoneal seeding was shown to be significantly lower than percutaneous CT guided FNA. The performance of this technique is dependent on the endoscopist and cytopathologist experience, the location, size and consistency of the tumour and the number of passes in the lesion. The type of echoendoscope or needle used does not influence the results, whereas it remains debated if presence of the cytopathologist on site might improve FNA performances. These last years, a new liquid-based cytology technique has been developed to process the specimen. Different methods exist to prepare this type of material and all these techniques improve EUS-FNA performance by decreasing the number of inadequate specimens and by increasing the possibility to obtain cell blocks allowing for ancillary techniques such as immunohistochemistry and molecular biology.

Biliary Tract Diseases↗
PubMedDate not supplied

[Mechanisms in hypergastrinemia in autoimmune atrophic gastritis and Helicobacter pylori infection].

The authors review recent progresses made in the understanding of the disturbed gastrin homeostasis in Helicobacter pylori infection and in pernicious anaemia. Regulation of gastrin release in a complex mechanism involving inhibition by a low gastric pH and several peptides including somatostatin, and stimulation by different factors, mainly alimentary peptides and amino-acids. The hypergastrinaemia observed in patients with Helicobacter pylori infection occurs despite a normal intraluminal pH. This may be through alkalinisation of the gastric mucus layer due to the production of ammonia by the bacterial urease or through local release of inflammatory mediators. In pernicious anaemia a factor present in the antacid gastric juice could explain the important hypergastrinaemia observed. The gastrin releasing activity of the gastric juice itself was demonstrated by a decrease of the patients' plasma gastrin concentration during a neutral gastric lavage and by a rise of the gastrin levels in rats whose stomachs were perfused with gastric juice from pernicious anaemia patients. A better understanding of the relation between gastric pH and gastrin release is important not only for these pathological states but also for treatments which suppress acid secretion.

Anemia, Pernicious↗
PubMedDate not supplied

Intraductal papillary-mucinous tumours of the pancreas. Clinical and radiological aspects.

Intraductal papillary-mucinous tumours are rare epithelial tumours with all intermediate types occurring from papillary to mucin-hypersecreting forms. They affects generally old men and recurring pancreatitis is the main clinical feature. Endoscopic Retrograde Pancreatography is the best diagnostic method, showing large dilatation of the ducts and filling defects due to mucin's plugs or papillary tumour. IPMT are slow-growing and have low malignant potential; as to far, surgical resection is considered mandatory, however, better distinction between benign and malignant evolution will probably select cases in which conservative follow-up may be proposed.

Adenocarcinoma, Mucinous↗