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1.
Dominique Toussaint-Demylle Jean-Marie Scheiff Stanislas Haumont 《Cell and tissue research》1990,262(1):115-123
Summary Thymic nurse cells (TNC), which are multicellular complexes composed of epithelial cells and thymocytes, were obtained from C3H-mice thymuses. They were described by means of light and electron microscopy. The morphology of epithelial cells forming isolated TNC compared to that of small tissue fragments obtained by enzymatic digestion revealed that TNC could be derived from all parts of the thymus: cortex, corticomedullary junction and medulla, the cortex being their principal source. This variety of origin, the presence of several epithelial cells inside a single TNC, the presence of non-lymphoid cells, and the various locations of eleaved desmosomes confirmed that their aspect in vitro as round and sealed structures can be considered to be an artifact due to the isolation technique used. Indeed, during this procedure, they are formed by a process of wrapping of the epithelial cytoplasm around the tightly associated thymocytes. All three epithelial cell types: cortical reticular cells, medullary reticular cells, and medullary globular cells can form TNC.A portion of this work was presented at the first Thymus Workshop. Rolduc, Netherlands, April, 1988 相似文献
2.
Monique Berthelon Catherine Caillaud Françoise Rey Philippe Labrune Dominique Melle Josué Feingold Jean Frézal Marie-Louise Briard Jean-Pierre Farriaux Pierre Guibaud Hubert Journel Bernard Le Marec Nicole Maurin Jean-Louis Nivelon Henri Plauchu Jean-Marie Saudubray Philippe Tron Jean Rey Arnold Münnich Stanislas Lyonnet 《Human genetics》1991,86(4):355-358
Summary A total of 252 chromosomes from 126 patients with phenylalanine hydroxylase (PAH) deficiencies were analyzed for both mutant genotypes and restriction fragment length polymorphism (RFLP) haplotypes at the PAH locus. The mutant genes studied originated either from Western Europe (116 alleles) or from Mediterranean countries (136 alleles). Only 27% of all mutant alleles were found to carry identified mutations, particularly mutations at codon 252 (2.3%), 261 (7.5%), 280 (6.3%), 408 (3.5%) and at the splice donor site of intron 12 (6.3%). The mutant genotypes were associated with RFLP haplotypes 7, 1, 38, 2 and 3 at the PAH locus respectively. Except for the splice mutation of intron 12, these associations were preferential, but not exclusive, since the other four mutations were found on the background of at least two RFLP haplotypes. These results, together with the observation that 85% of PAH deficient patients are heterozygotes for their mutant genotypes, emphasize the great heterogeneity of PAH deficiencies in Mediterranean countries and hamper systematic DNA testing for carrier status in this population. 相似文献
3.
Clinical and molecular heterogeneity of phenylalanine hydroxylase deficiencies in France 总被引:20,自引:10,他引:10 下载免费PDF全文
Franoise Rey Monique Berthelon Catherine Caillaud Stanislas Lyonnet Vronique Abadie Flicienne Blandin-Savoja Josu Feingold Jean-Marie Saudubray Jean Frzal Arnold Munnich Jean Rey 《American journal of human genetics》1988,43(6):914-921
RFLPs of 68 normal and 74 mutant alleles at the phenylalanine hydroxylase (PAH) locus were determined in 37 French kindreds. A total of 23 haplotypes, including 18 normal and 16 mutant alleles, were observed. Two-thirds of all mutant alleles were confined within only four haplotypes, while the last third was accounted for by 12 haplotypes, including eight haplotypes absent from Caucasian pedigrees reported thus far. Several mutant haplotypes were present in typical phenylketonuria only, others were present in variants only, and some were present in both. In addition, a particular mutant haplotype (haplotype 2) was found to harbor different mutations in our series, resulting in either typical phenylketonuria or in mild hyperphenylalaninemias. The diploid combination of so many mutant haplotypes in PAH-deficient patients and of compound heterozygosity at the PAH locus in southern Europe might account for the broad spectrum of individual phenotypes observed in France. 相似文献
4.
The reaction of protected 1,2-anhydro-α-d-gluco- and β-d-manno-pyranoses with alkyl and phenyl organocuprates afforded the corresponding C-glycosyl compounds in acceptable to high yield. Complete stereocontrol was obtained, leading respectively to the β-d or the α-d anomer. With the perbenzylated manno derivative, deoxygenation at C-2 was achieved in high yield, affording 2-deoxy-α-d-C-glycosyl compounds. 相似文献
5.
Cardiovascular and biological effects of K+ channel openers, a class of drugs with vasorelaxant and cardioprotective properties 总被引:3,自引:0,他引:3
Several new chemical entities (RP 52891, cromakalim and its derivatives) are potent and specific openers of vascular K+ channels. This mechanism is also shared, at least partially, by drugs such as minoxidil, diazoxide, pinacidil and nicorandil. The opening of plasmalemma K+ channels produces loss of cytosolic K+. This effect results in cellular hyperpolarization and functional vasorelaxation. In normotensive or hypertensive rats, K+ channel activators decrease aortic blood pressure (by producing a directly mediated fall in systemic vascular resistance) and reflexly increase heart rate. The former effect is not modified by specific blockers of classical vascular receptors but it is completely antagonized by the hypoglycemic sulphonylurea, glibenclamide, an established blocker of ATP-regulated K+ channels. K+ channel openers produce selective coronary vasodilatation and afford functional and biochemical protection to the ischemic myocardium. This salutary effect is mediated via cardiac K+ channel modulation and may result from an improved myocardial oxygen balance in the ischemic region. K+ channel openers increase plasma renin activity in animals as well as in man. However, only diazoxide, but not cromakalim or RP 52891, lowers plasma insulin concentration. The dose of glibenclamide entirely blocking the latter effect is over 50-fold smaller than that antagonizing the hypotensive and hyper-reninemic responses to diazoxide. In conclusion, K+ channel activators are potent vasorelaxant and cardioprotective agents possessing an original mechanism of action which is the opening of plasmalemma ATP-regulated K+ channels. Their clinical use as antihypertensive agents may be accompanied by undesirable effects (characteristic of peripheral vasodilators) which are likely to be attenuated or avoided by controlled release formulations. However, inasmuch as low doses of K+ channel openers may be sufficient to produce selective coronary artery dilatation and cardioprotection, these compounds could be of particular value in treating patients with coronary artery disease efficaciously and possibly without adverse cardiovascular effects. 相似文献
6.
Stanislas Tomavo Jean-Francois Dubremetz Ralph T. Schwarz 《Biology of the cell / under the auspices of the European Cell Biology Organization》1993,78(3):155-162
In this study we describe the biochemical features of the Toxoplasma gondii tachyzoite surface glycoprotein, gp23, demonstrating that it is attached to the parasite membrane by a glycosyl-phosphatidyl inositol anchor. Gp23 was metabolically labeled with tritiated palmitate, myristate, ethanolamine, inositol, glucosamine, mannose and galactose, as expected for a GPI-anchor structure. Gp23 was released from the surface of living parasites after treatment with phosphatidyl inositol-specific phospholipase C (PI-PLC) and the resulting water-soluble protein was immunoprecipitated with a monoclonal antibody specific for gp23. The GPIcore glycan was generated after aqueous-HF dephosphorylation followed by nitrous acid deamination and its carbohydrate structure was analyzed using selective exo- and endoglycosidase treatments. Finally, the phosphatidylinositol moiety of gp23 was characterized using PI-PLC and phospholipase A2 (PLA2) digestions. Our cumulative data suggest that gp23 of T gondii tachyzoites contains a modified GPI-backbone similar to the mammalian Thy-1 anchor, consisting of a conserved core structure (ethanolaminePO4-6-Manαl-2-Manαl-6-Manαl-4-GIcNαl-6-PI) bearing β-linked N-acetylgalactosamine residue(s). 相似文献
7.
A microanalytic study of particles transport across the alveoli: role of blood platelets 总被引:5,自引:0,他引:5
J P Berry B Arnoux G Stanislas P Galle J Chretien 《Biomedicine / [publiée pour l'A.A.I.C.I.G.]》1977,27(9-10):354-357
Following intratracheal injection of particles of colloidal gold (30 nm) in the rat, particles in the blood platelets of the alveolar capillaries can rapidly be observed. The presence of the gold is confirmed by microanalysis. The role of this phenomenon in pulmonary clearance is discussed. 相似文献
8.
9.
Lamberts RR Van Rijen MH Sipkema P Fransen P Sys SU Westerhof N 《American journal of physiology. Heart and circulatory physiology》2002,283(4):H1515-H1522
An increase in coronary perfusion, transversal stretch of the myocardium, increases developed force (F(dev)) (Gregg effect) through activation of stretch-activated ion channels (SACs). Lengthening of the muscle, longitudinal stretch of the myocardium, causes an immediate increase in F(dev) followed by a slow F(dev) increase (Anrep effect). In isometrically contracting perfused papillary muscles of Wistar rats, we investigated whether both effects were based on similar stretch-induced mechanisms by measuring F(dev) and intracellular Ca(2+) concentration ([Ca(2+)](i)) after a muscle length increase from 85% to 95% L(max) (length at which maximal isometric force develops) at low and high coronary perfusion before and after inhibition of SACs with gadolinium (10 micromol/l Gd(3+)). The increase of F(dev) and peak [Ca(2+)](i) by the Gregg effect was of similar magnitude as the Anrep effect (from 3.5 +/- 0.8 to 3.9 +/- 1.2 mN/mm(2) and from 3.0 +/- 0.7% to 3.8 +/- 0.9% normalized [Ca(2+)](i), means +/- SE). SAC blockade completely blunted the increase of F(dev) and peak [Ca(2+)](i) by the Gregg effect; however, it did not affect the Anrep effect. The slow force response, but not the calcium response, was augmented by an increase in coronary perfusion. Therefore, increased coronary perfusion, transversal stretch of the myocardium, and muscle lengthening, longitudinal stretch of the myocardium, increase myocardial contraction in the rat through different stretch-triggered mechanisms. 相似文献
10.
Morris MT Coppin A Tomavo S Carruthers VB 《The Journal of biological chemistry》2002,277(47):45259-45266
We have characterized a Kazal family serine protease inhibitor, Toxoplasma gondii protease inhibitor 1 (TgPI-1), in the obligate intracellular parasite Toxoplasma gondii. TgPI-1 contains four inhibitor domains predicted to inhibit trypsin, chymotrypsin, and elastase. Antibodies against recombinant TgPI-1 detect two polypeptides, of 43 and 41 kDa, designated TgPI-1(43) and TgPI-1(41), in tachyzoites, bradyzoites, and sporozoites. TgPI-1(43) and TgPI-1(41) are secreted constitutively from dense granules into the excreted/secreted antigen fraction as well as the parasitophorous vacuole that T. gondii occupies during intracellular replication. Recombinant TgPI-1 inhibits trypsin, chymotrypsin, pancreatic elastase, and neutrophil elastase. Immunoprecipitation studies with anti-rTgPI-1 antibodies reveal that recombinant TgPI-1 forms a complex with trypsin that is dependent on interactions with the active site of the protease. TgPI-1 is the first anti-trypsin/chymotrypsin inhibitor to be identified in bradyzoites and sporozoites, stages of the parasite that would be exposed to proteolytic enzymes in the digestive tract of the host. 相似文献