Biomedical subjects
C Clerc
Publications and source records attributed to C Clerc.
Percutaneous embolectomy: in vitro investigations of the self-expanding tulip sheath.
A self-expanding sheath with a tulip-shaped distal end was designed for performance of percutaneous embolectomy. Its ability to retrieve clots was tested in an in vitro flow model; results were compared with those obtained with a conventional 10-F sheath. Simulated embolectomy of clots weighing 0.1-1.5 g was performed with a 0.75-mL Fogarty balloon on a 4-F catheter. The clot material that embolized distally during the procedure was sampled and quantified. No effective embolectomy was performed via a conventional sheath. With the tulip sheath, however, complete clot removal was achieved unless the clot size exceeded the tulip volume. On the basis of results of in vitro testing, the tulip design is promising for use in several applications during percutaneous interventions.
Cutaneous interstitial fluid protein concentrations in the inflammatory syndrome: pharmacological consequences.
Concentrations of alpha 1 acid glycoprotein, albumin, transferrin, haptoglobin, immunoglobulins G, A, M and apolipoprotein B were measured in serum and suction blister fluid from a group of individuals presenting a biologically proven inflammatory syndrome, and from a control group. Protein values in suction blister fluid did not change from the 2nd to the 3rd h after the beginning of blister formation. The ratio of the concentration of proteins in blister fluid and serum did not differ significantly between the groups. However, a 25% decrease in blister fluid albumin and a 100% increase in blister fluid alpha 1 acid glycoprotein, recorded in the inflammatory group, were worth noting, since they possibly influence the tissular distribution of some protein-binding drugs. Finally, an inverse relationship was established between the blister fluid/serum concentration ratio and the respective molar mass of each protein.
Primary culture of adult rat hepatocytes after 48-hour preservation of the liver with cold UW solution.
Rat livers were perfused and stored for 48 hr in cold University of Wisconsin solution before dissociation by the two-step collagenase method. At that time, glycogen content was significantly reduced, but no obvious changes in albumin, beta-actin and aldolase B mRNAs and in glutathione levels were observed. Enzymatic perfusion yielded 280 +/- 30 x 10(6) viable hepatocytes vs. 520 +/- 40 x 10(6) viable hepatocytes from unstored organs. Cell viability determined by trypan blue exclusion was 74% and 90%, respectively. Hepatocytes from University of Wisconsin-preserved livers had a 29% reduced adenosine triphosphate content, but glutathione levels did not significantly differ from those found in unstored cells. When put into culture, hepatocytes formed typical monolayers of granular epithelial cells and did not exhibit alteration of their fine structure when compared with cells from unstored organs. After 24 and 48 hr, they showed variations in cytochrome P-450 content and ethoxyresorufin O-deethylase activity similar to those observed with unstored cells. By contrast, overall protein synthesis and albumin secretion rate were 40% and 30% lower, respectively. Hepatocytes from University of Wisconsin-preserved organs could be cryopreserved and further cultured as unstored cells. The University of Wisconsin solution was also used to preserve isolated hepatocytes. Viability of freshly isolated hepatocytes was decreased by only 10% after 48 hr of hypothermic liver storage when assayed by intracellular lactate dehydrogenase content. However, after 4 hr of storage, in contrast with hepatocytes preserved in L15 Leibovitz medium, the cells attached poorly to plastic and exhibited morphological alterations.(ABSTRACT TRUNCATED AT 250 WORDS)
Blood chemistry of human fetuses in the second and third trimesters.
Six biochemical parameters and four enzyme activities were determined from the serum of 76 healthy and 56 pathological human fetuses between the 20th and 38th week of pregnancy. In the normal fetuses studied within that period, creatinine, immunoglobulin M, lactate dehydrogenase, and gamma-glutamyltransferase increased; haemoglobin F and glucose progressively decreased; and alkaline phosphatase was at a peak around the 26th week; cholesterol and triglycerides were always low. The same parameters were also measured in some of the pathological fetuses and compared with their normal counterparts.
Effects of halothane on human and rat hepatocyte cultures.
The aim of this study was to investigate direct cytotoxicity to human and rat hepatocytes in primary culture from halothane and compare it with that of isoflurane, which is known to be minimally metabolized and less toxic in vivo. Both human and rat parenchymal cells were isolated by the two-step collagenase perfusion method and after attachment to plastic were incubated with either volatile anesthetic for 24 h. All the cultures were maintained in 20% O2 condition and were not induced prior to anesthetic treatment. Temperature, atmosphere conditions, and anesthetic concentrations were kept constant during the study period. Evaluation of cytotoxicity was based on morphologic, biologic (determination of both extracellular and intracellular lactate dehydrogenase activity), and metabolic (protein synthesis and secretion) end points. Protein synthesis and secretion rates were found to be the most sensitive parameters in hepatocyte cultures from both species. Protein synthesis was inhibited by 18% and protein secretion by 50% in the presence of 1 and 1.25 mM halothane, respectively, in human cell cultures (P less than 0.05). With 1.25 mM halothane intracellular lactate dehydrogenase was also decreased; lactate dehydrogenase leakage and morphologic alterations were detected only beyond 5 mM halothane. By contrast, in rat hepatocyte cultures protein secretion was inhibited by 26% and protein synthesis by 20% in the presence of 0.1 and 0.75 mM halothane, respectively, whereas morphologic alterations and a 37% lactate dehydrogenase leakage increase were observed with the concentration of 1 mM (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
Transitory deficit in high-density lipoproteins and apolipoprotein A-I.
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Interference of macro-creatine kinase in determination of CK-MB in serum with the Kodak Ektachem.
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Level of plasma fibronectin in patients with breast cancer.
Plasma fibronectin was determined by laser nephelometric immunoassay in two populations: healthy individuals and patients with metastatic or non-metastatic breast cancer. The results showed that the fibronectin concentration was higher in the patient group than in the healthy controls of similar age, with a significant difference (p less than 0.05). The patients who had metastatic breast cancer tended to show higher levels than those with no detectable metastasis, but such a difference was not statistically significant. Since fibronectin is sensitive to clinical events unrelated to the malignancy status, it does not seem suitable as a tumor marker.
[Use of monoclonal antibodies for the immunoenzymological determination of alpha-fetoprotein in amniotic fluid].
A two site immunoenzymatic assay using monoclonal antibodies for alpha-fetoprotein in amniotic fluid has been evaluated. Results obtained with monoclonal antibodies correlated well with those obtained by electroimmunodiffusion assay. The evaluation of this method has shown rapidity, accuracy and a better sensitivity than electroimmunodiffusion assay. Further more the measurements of both maternal serum and amniotic fluid alpha-fetoprotein can be associated.
[Use of monoclonal antibodies for the immunoenzyme determination of creatine kinase-isoenzyme MB].
An enzyme immunoassay using monoclonal antibodies for creatine kinase-MB in human serum is described. The specificity and the linearity have been studied. The coefficient of within assay ranges from 6% to 22.5% according to the concentrations. The coefficient of between-assay ranges from 8% to 16.6%. Compared to electrophoresis, the results obtained with the enzyme immunoassay are a better sign of the physical state of the patients.
[Prenatal diagnosis of abnormalities of the neuroectodermal tube. Limitations of the assay of amniotic alpha fetoprotein and acetylcholinesterase and value of the qualitative study of cholinesterases. Apropos of 6 cases of anencephaly].
Measurement of amniotic fluid alpha-foetoprotein and acetylcholinesterase for the detection of neural tube defects has been used in 285 normal or neural tube defects affected pregnancies: 18 false positive results (with non neural tube defects fetal malformations) have been reported. A qualitative polyacrylamide gel electrophoresis technique has been used to identify the acetylcholinesterase isoenzyme derived from foetal cerebrospinal fluid. Results illustrate the value of amniotic fluid acetylcholinesterase electrophoresis. Amniotic cholinesterase presence may serve as a valuable marker for the detection of neural tube defects.
[Amniotic fibronectin in normal pregnancy and pregnancy with fetal anencephaly].
Fibronectin, which is an important protein in plasma and in surface cells was calculated in amniotic fluid using a laser ray nephelemetric technique. In normal pregnancies (in 72 samples studied) this protein which rises towards the 18th week of amenorrhoea (mean +/- S.D.: 60.8 +/- 16.0 mg/l), decreases steadily to term (mean 14.8 +/- 8.9 mg/l). In fetal anencephaly (10 samples tested) high levels were also found but the difference as compared with normal levels was not significant. This measurement does not therefore constitute an extra way of screening for closure of the neural tube.
[Value of the demonstration of amniotic phosphatidylglycerol in pregnancy in diabetic women].
Correlation was made between phosphatidylglycerol (PG), L/S ratio results and respiratory distress syndrome (RDS). PG determination is an accurate predictor of fetal lung maturity in diabetic pregnancies: when it is present in amniotic fluid there is never risk of RDS for the infant.
[Otospongiosis and Lobstein's disease. Clinical, histological and histochemical comparison].
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Neointima formation following arterial placement of self-expanding stents of different radial force: experimental results.
PURPOSE: Radial force delivered by self-expanding stents has been discussed as a factor affecting thickness of neointima formation. METHODS: Two types of Wallstents were studied experimentally in vitro and in vivo. Due to an altered braiding angle of the stent filaments, one stent type (LS type) delivers half the radial force to the vascular wall than the conventional type. The radial force was evaluated in a compression-expansion test which related changes in stent length to the compressing force. Fourteen LS and 16 conventional stents were implanted into 15 femoropopliteal arteries of 10 dogs. Autopsy was performed after 4 weeks (14 stents) or 6 months (16 stents). RESULTS: All stents remained patent over the follow-up period with no evidence of stenosis. Neointimal overgrowth was complete and smooth in all. Medial atrophy was a constant finding after placement of both types. Neointimal thickness did not exceed 100 microns after 4 weeks and 6 months and did not significantly differ between LS stents and conventional stents. CONCLUSION: It is concluded that in normal dogs self-expanding stents of the Wallstent type do not induce neointimal buildup that exceeds 100 microns in the femoropopliteal artery. A reduced radial force was not found to result in reduced neointima formation.
[Cytoprotection (6). Models for studying hepatic cytoprotection].
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