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Biomedical subjects

G Durand

Publications and source records attributed to G Durand.

At least 199 records · Page 11Linked to original sources
PubMed1990

Respiratory cross-sectional area-flux measurements of the human chest wall.

A new device that utilizes the voltages induced in separate coils encircling the rib cage and abdomen by a magnetic field is described for measurement of cross-sectional areas of the human chest wall (rib cage and abdomen) and their variation during breathing. A uniform magnetic field (1.4 X 10(-7) Tesla at 100 kHz) is produced by generating an alternating current at 100 kHz in two square coils, 1.98 m on each side, parallel to the planes of the areas to be measured and placed symmetrically cephalad and caudad to these planes at a mean distance of 0.53 m. We demonstrated that the accuracy of the device on well-defined surfaces (squares, circles, rectangles, ellipses) was within 1% in all cases. Observed errors are due primarily to small inhomogeneities of the magnetic field and variation of the orientation of the coil relative to the field. Using a second magnetic field (80 kHz) perpendicular to the first, we measured the errors due to nonparallel orientation during quiet breathing and inspiratory capacity maneuvers. In 10 normal subjects, orientation effects were less than 2% for the rib cage and less than 0.7% for the abdomen. In five of these subjects, orientation effects at functional residual capacity in lateral and seated postures were generally less than or equal to 5%, but estimated tidal volume during spontaneous breathing was comparable to measurements in the supine posture. In five curarized patients, we assessed the linearity of volume-motion relationships of the rib cage and abdomen, comparing cross-sectional area and circumference measurements. Departures from linearity using cross-sectional areas were only one-third of those using circumferences. In seven normal subjects we compared cross-sectional area measurements with respiratory inductive plethysmography (RIP) and found comparable estimates of lung volume change over a wide range of relative rib cage contributions to tidal volume (-5 to 105%), with slightly higher standard deviations for the RIP (SD = 10% for RIP; SD = 4% for cross-sectional area).

Abdomen↗
PubMed1990

Control of brain fatty acids.

Saturated and monounsaturated fatty acids are mainly synthetized in the brain, but some of them could originate from the diet; in contrast polyunsaturated fatty acids are derived from dietary linoleic and linolenic acid. Saturated fatty acid biosynthesis occurs via three main pathways in mammalian cells. One is de novo synthesis of fatty acids from acetyl-CoA via malonyl-CoA; this system has been isolated in soluble form (the soluble system) from various animal tissues including brain. The second and third pathways involve elongation: in the mitochondrial system, acetyl CoA is the principal substrate in extracts from all organs, even brain; in the microsomal system, however, malonyl-CoA acts as donor of the 2 carbon fragments. In vivo studies in brain have shown that very long chain fatty acids are synthesized by elongation rather than by a than by a de novo mechanism. Feeding animals with oils that have a low n-3 acid content (linolenic series) results in all brain cells and organelles reduced amounts of 22:6 n-3 which is compensated for by an increase in 22:5 n-6. The speed of recuperation from these anomalies is extremely slow for brain cells, organelles and microvessels, in contrast with other organs. Essential fatty acids for the brain could be those with very long chains as shown with cell culture. They are probably synthesized in the liver from linolenic acid. They can also be supplied directly by food. During the period of cerebral development there is a linear relation between the n-3 acid content of the brain and that of food until linolenic acid represents approx. 200 mg per 100 g of food (for 1200 mg linoleic acid). A decrease in acids of the linolenic series in the membranes results in a 40% reduction of Na-K-ATPase in nerve terminals and a 20% reduction in 5'-nucleotidase in whole brain homogenate. A diet low in linolenic acid leads to anomalies in the electroretinogram which disappear partially with age, it seriously affects learning tasks. The presence of linolenic acid in the diet confers a greater resistance to certain neurotoxic agents.

Animals↗
PubMed1990

Polyclonal antibody-based enzyme-linked immunosorbent assay of alpha 1-acid glycoprotein.

This is a noncompetitive enzyme-linked immunosorbent assay for measuring low concentrations (2 to 100 micrograms/L) of human alpha 1-acid glycoprotein (AGP; orosomucoid). The method is based on a simple "sandwich" technique involving polyclonal rabbit antisera against AGP. Mean within-run and total (between-run) CVs were 6.2% and 9.7%, respectively. Analytical recovery, tested in various biological fluids, averaged 101%. The technique has been successfully applied to diluted biological fluids such as bronchoalveolar lavage, cerebrospinal and amniotic fluids, and hepatocyte-culture supernates. Because of its analytical validity and the commercial availability of the reagents, this assay is suitable for large-scale determinations of AGP concentrations in those biological fluids in which its concentration is relatively low.

Amniotic Fluid↗
PubMed1990

[Preliminary results of a mass screening program for colorectal cancer].

The Digestive Tumours Registry of Burgundy set up a study to assess acceptability and results of colorectal cancers screening using the Hemoccult test. A total of 95,000 people, aged 45 to 74, were included, 55,000 in 1988 and 40,000 in 1989. The aim of this paper is to report the results of the first screening process in the population tested from January to July 1988, i.e. 27,421 subjects. Information on colorectal cancer was mailed to all homes in the screening areas and a news campaign was organized. During the first 4 months, the general practitioners (GPs) either prescribed the test which was then reimbursed (Autun area), or gave it free to their patients (other areas). After that phase, the test was mailed to all subjects who had not consulted their GP, and a second letter was sent 1 month later when the test had not been sent back. A total of 14,603 subjects performed the Hemoccult test (53.3 percent). Acceptability was higher in those areas there the test was initially given free by the GPs (57.3 percent) than in those where it was prescribed (40.0 percent). Acceptability was higher in women (55.8 percent) than in men (50.6 percent). A total of 57.8 percent of the performed tests were done during the medical offer phase, 29.1 percent after mailing and 13.1 percent after the recall letter. There was a positive test in 340 subjects (2.3 percent) and 288 (84.7 percent) had colonic investigations, a colonoscopy in 99 percent of the cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenoma↗
PubMed1990

[Evaluation of the inflammatory process in hepatic disorders: immunochemistry of C alpha-reactive protein and of alpha 1-acid glycoprotein].

C-reactive protein (CRP) and alpha 1-acid glycoprotein (alpha 1-GPA) two acute phase reactants, have both been monitored in patients suffering from hepatocellular diseases, compared with healthy subjects. Immunochemical findings, in hepatic amebiasis, revealed a higher incidence of increased alpha 1-GPA levels (86% of patients, as compared to 46% for CRP), whereas during liver primitive cancer and cirrhosis inverse pattern occurs. In viral chronic hepatitis, lesser perturbations were observed. In contrast, a simultaneous increase of both proteins is strong supporting evidence for the severity of disease with an unfavourable prognostic.

Adolescent↗
PubMed1990

[Contribution of high resolution x-ray computed tomography to the diagnosis of pulmonary histiocytosis X. Apropos of 12 cases].

The authors studied the value of high resolution computed tomography in twelve patients with pulmonary histiocytosis X. The aim of this study was to define the CT signs. More or less thin-walled air-filled cysts were observed in all but one case, although the subsequent follow-up of this case revealed the development of such cysts 6 months later. Nodules were also present in all but two cases. They sometimes consisted of excavated nodules. Reticulations, "frosted glass" appearance and irregularities of interface--all signs of a classical interstitial syndrome--were observed less frequently. The lesions were always diffuse, cortical and medullary. The predominance for the upper lobes was only observed in 50% of cases. The case examined on 2 occasions during the course of the disease at an interval of 6 months suggested the progression of small solid nodules towards larger, excavated nodules, finally resulting in thin-walled cysts which may eventually coalesce to force a "lacework" appearance. The pathophysiology of this progression of the lesions and therefore of the pulmonary eosinophilic granuloma is discussed by the authors.

Adult↗
PubMed1989

Microheterogeneity of the carbohydrate moiety of human alpha 1-acid glycoprotein in two benign liver diseases: alcoholic cirrhosis and acute hepatitis.

To determine whether alterations of the carbohydrate moiety of human alpha 1-acid glycoprotein constitute a marker of hepatic damage we studied purified alpha 1-acid glycoprotein from healthy individuals and two groups of patients with benign liver diseases: alcoholic cirrhosis and acute viral hepatitis. The results indicate: (1) increased concanavalin A-non reactive forms in cirrhosis and hepatitis, (2) a markedly increased proportion of fucosyl residues in all cirrhotic and some hepatitis patients. Although hyperfucosylation is generally considered to be a tumor marker, the observation here in the two benign liver diseases indicates that an increased fucosyl content should be considered as a more general expression of pathological glycoconjugate metabolism.

Acute Disease↗
PubMed1989

Variations in the rate of secretion of different glycosylated forms of rat alpha 1-acid glycoprotein.

Various studies have shown that oligosaccharides play an important role in the intracellular transport and secretion of glycoproteins. We show here a difference in the rate of secretion of two mature glycoforms of a single protein, alpha 1-acid glycoprotein. This indicates the existence of kinetically different pathways for these two forms for transport from the medial Golgi to the extracellular medium.

Albumins↗
PubMed1989

Con A affinity of rat alpha 1-acid glycoprotein (rAGP): changes during inflammation, dexamethasone or phenobarbital treatment as detected by crossed affino immunoelectrophoresis (CAIE) are not only a reflection of biantennary glycan content.

Using crossed affino immunoelectrophoresis (CAIE), the secretion of the Con A most reactive form (CAIE-3) of rat alpha 1-acid glycoprotein (rAGP) has been shown to be increased in sera of Wistar and Sprague Dawley rats during inflammation and treatment with dexamethasone or phenobarbital. Primary hepatocyte cultures prepared from experimentally treated Wistar rats reflect these in vivo findings, since rAGP as present in corresponding secretion media shows similar changes in Con A reactivity. In this study, the relation of this increase towards the amount of biantennary glycans was investigated for both differently treated rat strains. For this purpose, metabolically labelled rAGP, secreted by isolated hepatocytes under the various conditions, was separated on Con A-Sepharose into four fractions. For each fraction of rAGP its behaviour in CAIE was established, revealing a positive correlation for Con A reactivity between the two methods. However, the enormous increase in Con A reactivity of rAGP in CAIE during inflammation and other conditions (increase in CAIE-3), could not be shown using Con A-Sepharose chromatography. Glycopeptides of each fraction were prepared and the amount of biantennary glycans was assessed. Contrary to expectations, an increase of the total amount of biantennary glycans of rAGP, secreted during conditions associated with an increase in CAIE-3 was not found. The independency of the results with regard to rat strain and procedures used underlined the generality of these findings. Consequently, not only the biantennary glycan content is responsible for the separation of rAGP in CAIE. The importance of other differences in glycosylation, e.g. sialylation, for the increase of rAGP CAIE-3 during various experimental conditions is discussed.

Acute-Phase Proteins↗
PubMed1989

Decreased number of asialoglycoprotein receptors in diabetic BB Wistar rat.

The binding of asialoglycoproteins by hepatic binding protein was studied in freshly isolated hepatocytes from genetically diabetic BB Wistar rats. The number of cell surface asialoglycoprotein receptors was dramatically decreased (58,000 +/- 38,000 for diabetic rats compared to 267,000 +/- 70,000 for normal rats), while the association equilibrium constant was not changed. These results parallel those obtained with streptozotocin-diabetic rats and support the hypothesis that insulin deprivation is responsible for the decrease in the receptor number.

Animals↗
PubMed1989

One-step purification of rat plasma alpha 1-acid glycoprotein by antibody affinity chromatography: application to normal and inflamed rat sera.

Most purification procedures used previously to isolate alpha 1-acid glycoprotein (AGP) from plasma can lead to some alterations in its carbohydrate moiety. An immunoaffinity chromatographic method is proposed for purifying in one step rat plasma AGP without any detectable modification of its glycan moiety. Crossed immunoaffinoelectrophoresis with concanavalin A before and after purification showed identical patterns, suggesting no glycan selection during the purification. In the same way no desialylation occurred during the purification step. This immunoaffinity chromatographic procedure provided evidence of a decreased level of fucosyl residues in turpentine oil rat plasma AGP compared with normal rat plasma AGP.

Animals↗
PubMed1989

Endocytosis of alpha 1-acid glycoprotein variants and of neoglycoproteins containing mannose derivatives by a mouse hybridoma cell line (2C11-12). Comparison with mouse peritoneal macrophages.

Macrophages from various origins are known to express membrane lectins that mediate the endocytosis of mannose-bearing glycoconjugates. Most macrophage tumor cell-lines lack such receptors. In this paper we show by flow cytometry analysis that a newly generated macrophage hybridoma (2C11-12), which displays several macrophage characteristics, also expresses mannose membrane lectins, resulting in the internalization of fluoresceinylated neoglycoproteins into acidic compartments. Thioglycolate elicited mouse peritoneal macrophages and the 2C11-12 hybridomas were compared by flow cytometry with regard to the binding and endocytosis of alpha 1-acid glycoprotein (AGP) variants separated by affinity chromatography on immobilized concanavalin A. AGP C eluted specifically with methyl alpha-mannopyranoside, which contains two bi-antennary oligosaccharides, was endocytosed as mannosylated serum albumin (Man-BSA). In both types of macrophages, the fluoresceinylated ligands were internalized in acidic compartments as demonstrated by the fluorescence intensity increase upon monensin post-incubation. However the behaviour of the internalized ligands was found to be quite different. AGP C and Man-BSA were rapidly degraded by thioglycolate elicited peritoneal macrophages and excreted in the medium as small peptide fragments; conversely they remained a longer time in the 2C11-12 hybridoma.

Animals↗
PubMed1989

Brain cell and tissue recovery in rats made deficient in n-3 fatty acids by alteration of dietary fat.

Rats were fed a purified diet containing either 1.5% sunflower oil [940 mg linoleic acid [18:2(n-6)]/100 g diet; 6 mg alpha-linolenic acid [18:3(n-3)]/300 g diet] or 1.9% soybean oil [940 mg 18:2(n-6)/100 g diet; 130 mg 18:3(n-3)/100 g diet]. In all cases and tissues examined 22:6(n-3) was lower and 22:5(n-6) was higher in rats fed sunflower oil than in rats fed soybean oil. Levels of 22:4(n-6) and 20:4(n-6) were largely unaffected. Expressed as a percentage of that in soybean oil-fed rats, 22:6(n-3) in sunflower oil-fed rats was as follows: neurons, 49; astrocytes, 47; oligodendrocytes, 10; lung, 27; testes, 32; retina, 36; liver, 35 and kidneys, 45. Ten wk after the change in diet of 60-d-old rats from one containing sunflower oil to one containing soybean oil, the fatty acid composition of the brain cells had not reached control values, e.g., that obtained in animals continuously fed soybean oil; 22:6(n-3) was 77, 65 and 80% of control levels for astrocytes, oligodendrocytes and neurons, respectively. In contrast, the recovery measured by the decay of 22:5(n-6) was complete within 10 wk. For 22:6(n-3), it took approximately 2 wk for liver and kidney to recover to the control value, 3 wk for lung, 6 wk for retina and 10 wk for testes. The decrease of 22:5(n-6) was rapid: the control values were reached within 2 wk for kidney, liver and lung and within 6 wk for retina.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗