Biomedical subjects
Publications and source records attributed to H Dupont.
Pulmonary artery perforation by a Swan-Ganz catheter is an uncommon but severe complication with high mortality. We report a case of perforation and discuss mechanisms and predisposing factors associated with this accident.
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The enzyme-linked immunofiltration assay (ELIFA) has been used for the rapid detection of electrophoresed proteins transferred from gels to immobilizing matrices. By controlled filtration, ELIFA permits the saturation of nylon or nitrocellulose membranes and the immunodetection of blotted antigens to be carried out in 15 min. The method is simple, can be automated and requires no handling of membranes. It complements the well standardized steps of gel electrophoresis and semi-dry horizontal electroblotting which can themselves be carried out in less than an hour. The sensitivity is at least 1-5 ng. The same process can be extended to the accelerated characterization of glycoproteins using appropriate ligands, or to the identification of antigens in a variety of biological fluids.
The enzyme-linked immunosorbent assay (ELISA) and enzyme-linked immunofiltration assay (ELIFA) sandwich methods have been compared for their ability to detect staphylococcal enterotoxin B (SEB) in biological samples. Using the avidin-biotin amplification system in the ELISA, high sensitivity was observed and staphylococcal protein A interference was completely prevented. In contrast, ELIFA was less sensitive than ELISA, but very easy to perform, fast and simple to read routinely.
Enzyme-linked immunofiltration assay (ELIFA) for labeling transferred proteins is an interesting and powerful technique for the rapid specific detection (15 min) of proteins immobilized on nitrocellulose or nylon membranes (0.20 and 0.45 micron). ELIFA does not require fastidious handling of the membranes. Saturation, specific labeling and washing procedures are achieved by filtration, controlled by a monitoring unit which regulates the flow rate and ensures excellent specificity, repetition and reproducibility. The recycling by closed circuit or by repetitive inversion of the flow direction offers the advantage of reducing the volumes of expensive reagents while simultaneously increasing the sensitivity of the technique. The detection limit is at least as low as 1-5 ng using directly or indirectly enzymatically labelled probes. ELIFA may be extended to the identification of glycoproteins using specific ligands such as lectins or to the immunocapture of an antigen using specific antibodies immobilized on an activated membrane. ELIFA complements fast separation, by e.g., isoelectric focusing, polyacrylamide gel electrophoresis, or sodium dodecyl sulfate-polyacrylamide gel electrophoresis and accelerated electrotransfer to membranes with rapid detection reducing the total time for separation transfer and detection to less than 2 h.
Previous investigations of the liver estrogen-specific binding in the newt, Pleurodeles waltl, have identified in the cytosol fraction, only from normal males, a new middle-affinity estrogen-binding component (MEBC) displaying the properties of type II sites reported in various tissues of vertebrates. The present work demonstrates that MEBC sites are not unique to the male but are also present in the nuclei of female animals. However, comparative study between males and females of liver nuclear sites under various extraction conditions shows sex-linked differences in the subnuclear localization. The relationships between the association states of MEBC in the nuclear compartment according to sex and their presence or absence in the cytosol fraction are discussed.
The effects of hormonal changes on the male-specific, middle-affinity, estrogen-binding component (MEBC) were investigated in the Pleurodele. Induction of MEBC was shown to be under androgen control, similar to that observed for the cytoplasmic middle-affinity estrogen-binding sites in rat liver and human hepatoma cells. But, in contrast to the male-specific middle-affinity estrogen-binding sites identified in the rat, the administration of estrogen to male Pleurodeles did not lead to the disappearance of MEBC but raised levels significantly. The MEBC displays the properties of type II middle-affinity estrogen-binding sites, which are characterized by an oestrogen-dependent rise, a sensitivity to reducing agents, a specificity for diethylstilbestrol, and a binding capacity enhanced by increasing dilutions of cytosol. In female Pleurodeles, MEBC can be induced by treatment with androgens. This induction appears to be modulated by the estrogen/androgen ratio. The induction of MEBC and the estrogen-dependent increase in the male were not found to be correlated with hepatocyte proliferation.
The inhibition of cytochrome P-450 dependent hydroxylations of bufuralol (BH) and antipyrine, and O-deethylation of 7-ethoxycoumarin (7-ECOD) by several monoamine oxidase inhibitors (MAOIs) was investigated in rat liver microsomes. According to their IC50 values, clorgyline was the most potent inhibitor while toloxatone, the only reversible MAOI in this study, was the least potent. A great variability of inhibitory potencies was found, even in the same chemical class of MAOIs. Irreversible inhibition of BH and 7-ECOD has been studied. Rapid irreversible inhibition occurred in some cases, and this could be responsible for in vivo inhibition after repeated dosing of these MAOIs.
Rabbits given a hypercholesterolemic diet (500 mg/day) for 6 months and then maintained for another 6 months on a normal diet were found to have developed fibrous lipidic lesions in the aorta. Although circulating platelet levels in these animals were normal there was a reduction in mean megakaryocyte ploidy. The high concentrations of megakaryoblasts in all the sedimentation fractions collected by the 'STAPUT' system suggested an increase in megakaryocyte turnover with activation of committed stem cells. In addition, other defects in maturation of megakaryocytes were observed, such as abnormalities in the demarcation membrane system and granule number. These data reveal that defects in megakaryocyte maturation and turnover may occur during the process of reparative fibrosis of the arterial tree following a period of moderate hypercholesterolemic diet in the rabbit.
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Saturation analysis over a wide range of [3H]estradiol-17 beta concentrations (1-40 nM) in cytosols prepared from liver of the newt Pleurodeles waltl of both sexes revealed a sex-linked heterogeneity of the estradiol-17 beta binding sites. In females, one type of binding site has been identified as a classical receptor. It exhibited a high affinity for estradiol-17 beta (Kd = 9 X 10(-9) M), had a high specificity for estrogenic compounds and was stabilized by monothioglycerol. In males, in addition to the receptor found in females, a second estrogen binding component was detected, not observed in female cytosols. It exhibited a Kd of 4.8 X 10(-8) M for estradiol 17 beta, higher capacity and displayed the same highly specific estrogen binding as does the estrogen receptor. It was affected by monothioglycerol and its binding was found to be significantly increased on cytosol dilution, as well as by estrogen-treatment.
Separation by velocity sedimentation at unit gravity according to the STAPUT system of Miller and Phillips was applied to a population of rabbit megakaryocytes previously enriched by density gradient centrifugation. By this means, 80,000 to 100,000 megakaryocytes with 100% purity were collected in eight fractions according to size for a sedimentation velocity of 52 to 30 mm/hr. DNA-Feulgen cytophotometric measurements show significant correlation between megakaryocyte size and ploidy. The study of the eight purified fractions is of particular interest because it reflects megakaryopoiesis evolution. The different stages of megakaryocyte maturation of each fraction were analysed by transmission and scanning electron microscopy and were correlated to ploidy level. Thrombopoietic megakaryocytes with grape-like appearance were found in ploidy fractions 8n to 128n. Cytophotometric determinations of nucleohistones revealed several populations.
Barlow and Vosa's (1970) quinacrine coloration procedure was performed on human seminal smears from normal volunteers and on subjects who were selected from those couples who were consulting us for sterility. This analysis proves the specificity of the quinacrine coloration test, and reveals a significant decrease in the numbers of Y-spermatozoa in oligospermic patients with teratospermia and asthenospermia. The role of structural modifications of the chromatin in producing this effect is postulated. Particulars are given of how to perform the coloration technique on specially fixed slides and a table is given showing the frequency of spermatozoa with the Y chromosome in relationship to the parameters of the semen analysis. Furthermore the figures given in the literature by other authors are compared with those of this study and this altogether proves the reliability of the technique developed.
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A new lethal disorder affecting two brothers is described. The features were curvature of the long bones, multiple fractures, dysmorphic facies, syndactyly and absence of ossification in the cranial vault. The condition could be inherited as an autosomal recessive or sex linked condition.
343 children with acute diarrhea were studied from january 1976 to september 1977. Rotavirus was the agent most frequently isolated (18 per cent) followed by Shigella (12 per cent) and Salmonella (10 per cent). Enterotoxigenic E. coli was identified in 8 per cent and invasive E. coli only in two cases. 80 per cent of isolated rotavirus fell in the neonate group and 25 per cent in the infant group. Diarrhea caused by rotavirus had a short duration, fever was negligible and abundant liquid stools were present without leukocytes in the fecal mucus and with a high percentage (48 per cent) of transient lactose intolerance. Polymorphonuclear leukocytes were found in fecal mucus in 75 per cent of cases caused by Shigella and only in 40 per cent of cases where the causal agent was Salmonella.