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Biomedical subjects

P Burtin

Publications and source records attributed to P Burtin.

At least 19 recordsLinked to original sources

[Infectious risk in day-nursery children].

High proximity in daycare centers is a well established risk factor for upper respiratory tract infections as well as Haemophilus influenza meningitis. Many studies have also reported the development of gastroenteritis as well as hepatitis A outbreaks in daycare centers; however, because of lack of controls, these studies do not provide enough information about the excess of risk attributable to daycare attendance. Main risk factors such as age, or seasons, are still very important in daycare centers and studies have also shown that a protection occurs rapidly after the beginning of attendance, may be in relation to the stimulation of the non-specific immunity. All these results do not provide enough data to implement a rational intervention project. More studies have to be carried out to assess the long term consequences (at school age for instance) of these infections. In order to make a rational decision regarding daycare attendance, it is important to have a global assessment of all the effects related to attendance (which are numerous and sometimes opposite); studies focusing on a single aspect of daycare attendance, or on its short term effect, may result in partial and misleading conclusions.

Child, Preschool

Visualization of the plasmin receptor on carcinoma cells.

In order to visualize the receptor for plasmin and plasminogen present on human carcinoma cells, SW1116 and MCF7-MF cells were incubated with biotinylated plasminogen or plasmin and fluoresceinated streptavidin, and counterstained with propidium iodide. It was first demonstrated that biotinylation did not alter the binding properties of plasminogen and plasmin, provided that the biotinylation rate was around 2. Specific staining of tumor cells was obtained using these reagents. Images with green fluorescence were clearly visible as grains or contours at the surface of tumor cells. The localization of fluorescent grains was analyzed more precisely using confocal microscopy. The percentage of stained cells varied from one experiment to another between 10 and 60%. In no experiment were all the cells observed to be positive. Mitotic cells were more frequently stained than non-mitotic cells, suggesting a relationship between the presence of plasmin receptors and cell proliferation. This was confirmed by the use of Ki67 monoclonal antibody (MAb), as B-Pg-binding tumor cells generally had their nucleus stained by this antibody. Other images indicated staining of the extracellular matrix. Finally, 2 rat tumor-cell sub-lines of colonic origin (DHD K12 Pro-b and Reg-b) were shown to bind human biotinylated plasminogen, confirming the strong interspecies reactivity of plasmin receptors.

Animals

Pharmacokinetics of midazolam during continuous infusion in critically ill neonates.

Midazolam is a water soluble benzodiazepine, with a short elimination half-life in adults and children. An IV bolus (0.2 mg.kg-1) immediately followed by continuous infusion of 0.06 mg.kg-1.h-1 was administered to 15 critically ill neonates at a gestational age of 32.8 weeks, who required sedation for mechanical ventilation. Heart rate and blood pressure were closely monitored. Hypotension occurred in 4 patients after the bolus dose or during the continuous infusion. Three of them had also been given fentanyl. Individual pharmacokinetic parameters were calculated: plasma clearance was 3.9 ml.min-1, elimination half-life was 12.0 h. Because of its short half-life compared to diazepam, midazolam may be used during the neonatal period to achieve rapid, brief sedation. However, it should be administered cautiously to neonates, particularly in premature infants, or if fentanyl is also given.

Blood Pressure

[Continuous venovenous hemofiltration after cardiac surgery. A retrospective study in 16 patients with multiple organ failure].

As intermittent haemodialysis in critically ill patients is often associated with circulatory instability and hypotension, pumped continuous veno-venous haemofiltration (CVVH) has been proposed as an alternative. This technique was used postoperatively in 16 cardiac surgery patients with cardiogenic shock (cardiac index < 2.2 l.min-1.m-2), anuria and multiple organ failure. A mean haemofiltration rate of 0.5 to 1 l.h-1 was used. Average length of treatment was 57 +/- 38 h. Two patients were improved and weaned from CVVH after 96 and 144 h respectively. The other fourteen died. A mean 200 +/- 50 ml of liquid were removed every hour. The technique was well tolerated by the cardiovascular system. The systolic arterial pressure, heart rate and cardiac index remained unchanged. Body weight had decreased by 3 +/- 1 kg after 48 h of use. Similarly, serum creatinine concentration was lowered from 337 +/- 32 mmol.l-1 to 252 +/- 27 mmol.l-1 (p < 0.001). At that time, urea and creatinine clearances were 18 +/- 2 ml.min-1, and 15 +/- 1 ml.min-1 respectively. After 24 h of CVVH, both serum sodium and potassium concentrations had been decreased, from 148 +/- 3 mmol.l-1 to 142 +/- 2 mmol.l-1 (p < 0.001), and from 5.7 +/- 0.3 to 4.2 +/- 0.15 mmol.l-1 (p < 0.001) respectively. In addition, pH increased significantly from 7.13 +/- 0.1 to 7.30 +/- 0.04 (p < 0.001). These results were comparable with these of other authors regarding safety and efficiency of CVVH. The low patient survival rate (12.5%) was due to the severity of cardiac impairment.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Kidney Injury

Plasminogen receptors on rat colon carcinoma cells.

Cells from rat carcinoma cell lines PROb (giving progressive tumours) and REGb (giving regressive tumours) have cell surface receptors which bind specifically rat plasminogen and plasmin. Affinity for Pg was found to be higher in PROb (Kd = 10(-7) M) than in REGb cells (Kd = 5.10(-7) M) but with a concomitant decrease in the number of binding sites, 0.9 x 10(6)/cell (range from 0.6 to 1.2 x 10(6)) in PROb vs 3.6 x 10(6)/cell (range 1.2 to 6 x 10(6)) in REGb cells. The number and the affinity of binding sites varied in an opposite way in PROb and REGb cells. The difference in affinity parameters was unrelated to the degree of invasiveness of tumour cells in syngenetic rats. Bound plasmin retained its enzymatic activity, which indicates that its binding does not involve the catalytic active site. In cell solubilisates plasminogen receptor appeared as one major band situated in the area of 50-60 kDa.

Animals

Penetration of ofloxacin into heart valves, myocardium, mediastinal fat, and sternal bone marrow in humans.

Ofloxacin penetration into heart tissue (valve and myocardium), mediastinal fat, and sternal bone marrow was the object of a prospective nonrandomized study. Thirty-six patients undergoing mitral and/or aortic valve replacement were included. Patients were divided into two groups of 18 patients each. Group 1 patients were administered a single 400-mg intravenous dose of ofloxacin over a 30-min period upon anesthesia (n = 6) or at 1 h (n = 6) or 6 h (n = 6) prior to surgery. Group 2 patients received a 200-mg oral dose of ofloxacin every 12 h during the 48 h preceding surgery. In this group, the final dose of ofloxacin was administered 3 h (n = 9) or 8 h (n = 9) before anesthesia. Plasma and tissue ofloxacin concentrations were assayed by high-pressure liquid chromatography. In group 1 patients, the peak level in plasma was 15.9 +/- 2.5 micrograms/ml. Peak ofloxacin levels in tissue were reached by hour 1 and were 8.89 +/- 2.16 micrograms/g in myocardium and 5 +/- 0.75 micrograms/g in heart valves. A significant decrease in ofloxacin levels in heart valve tissue and sternal bone marrow was observed after hour 3. Nevertheless, ofloxacin myocardial, heart valve, and sternal bone marrow levels remained higher than the MICs for the usually susceptible pathogens for at least 3 h. In group 2 patients, myocardial levels were long lasting (6.46 +/- 1.92 micrograms/g [4 to 8 h] and 5.92 +/- 0.95 micrograms/g [8 to 12 h]) and remained higher than those observed in the other tissues over the entire study period. A progressive but insignificant decrease in ofloxacin heart valve levels was observed (from 2.46 +/- 0.40 micrograms/g [4 to 8 h] to 1.57 +/- 0.22 micrograms/g [8 to 12 h]). In both groups, concentration in mediastinal fat were lower and tended to decrease with time. These were 1.83 +/- 0.61 micrograms/g with the first hour and 0.85 +/- 0.43 micrograms/g between hours 8 and 12 in group 1 and 1.74 +/- 0.52 micrograms/g between hours 4 and 8 and 0.67 +/- 0.11 micrograms/g between hours 8 and 12 in group 2. In conclusion, satisfactory diffusion of ofloxacin into heart tissue seems to favor use of the drug in the treatment of bacterial endocarditis due to susceptible pathogens. Furthermore, the progressively decreasing concentrations observed in heart valve and sternal bone marrow and the poor levels achieved in mediastinal fat suggest the need for renewing injection 3 h following initial infusion if the drug is used as an antibiotic prophylactic agent during cardiovascular surgery.

Adipose Tissue

[Management of a focal hepatic mass: propositions of a workshop].

Focal hepatic masses are a common problem, due to the expansion of ultrasound. Individuals engaged in the four disciplines involved (hepatogastroenterology, digestive surgery, radiology and pathology) met to summarize the information available, to compare their experience and to make synthetic proposals. The method consisted of an expert report, discussion of the clinical cases, workshop discussion for each discipline around synthetic proposals, reporting of these proposals in full session and discussion. The results, i.e. the synthetic and consensual proposals concerned diagnosis, treatment and monitoring of focal hepatic masses are presented for each discipline.

Biopsy

[Lymphoproliferative syndromes after cardiac transplantation and treatment with cyclosporine. Report of 4 cases].

Immunosuppressive therapies may induce neoplasia. The administration of cyclosporine is associated with an increased frequency of lymphoproliferative disorders when compared with conventional therapies. This risk is related to the type of organ transplanted and immunosuppression modalities (type and intensity). In heart transplantation, the incidence of non-Hodgkin's lymphoma varies between 11.9 and 1.5% with onset usually about 6 months after transplantation. Four case reports are presented; 3 lymphomas and 1 multiple myeloma that developed, in heart transplant recipients receiving triple-drug immunosuppression: azathioprine, cyclosporine and prednisolone. Clinical and immunohistological characteristics of posttransplant lymphomas are described and etiopathological mechanisms, especially the role of cyclosporine, in the development of these lymphoproliferative disorders, are discussed.

Adult

[Predictive factors of response to chemotherapy in epidermoid cancer of the esophagus. Study apropos of 60 patients and evaluation of a response score].

The aim of this study was to select predictive factors for response to chemotherapy in esophageal squamous cell carcinoma. Sixty patients, aged between 39 and 77 years (mean 61.5) received two initial chemotherapy sessions of 5 FU (1 mg/m2/24 h) and cisplatinum (20 mg/m2/24 h) during four days. Sixteen clinical, endoscopic, biological, and histological factors were collected. The response to chemotherapy was evaluated one month after completion of the second session by means of endoscopic and computed tomographic data. Thirty-two percent (CI: 20-44 percent) of patients had an objective response to chemotherapy (according to WHO criteria). Univariate analysis showed two predictive factors: obstructing pattern of tumor (P less than 0.01) and albuminemia less than 35 g/l (P less than 0.01). A response score was calculated with a stepwise regression model. The score correctly predicted a satisfactory response to chemotherapy with a sensitivity and specificity of 84.2 and 73 percent, respectively. Overall survival of these patients was statistically higher (P less than 0.001) compared with patients without any response. A satisfactory response to chemotherapy in patients with esophageal squamous cell carcinoma can be expected according to certain pretreatment factors.

Aged

A receptor for plasminogen and plasmin on human and rat carcinoma cells. Evidence for strong interspecific reactivity.

We have previously demonstrated the existence of a receptor for plasmin and plasminogen on carcinoma cells, either from human or rat origin. We show here that these receptors have a strong interspecific reactivity. This conclusion is based on binding assay of 125I labelled plasminogens and fluorescence experiments using biotinylated human plasminogen. In all these experiments cells from one species could bind plasminogen from the other species and interspecific inhibition was observed as well.

Animals