Active-site-directed inactivators of the Zn2+-containing D-alanyl-D-alanine-cleaving carboxypeptidase of Streptomyces albus G.
Charlier, Paulette ; ; et al
in Biochemical Journal (1984), 219(3), 763-772
Several types of active-site-directed inactivators (inhibitors) of the Zn2+-containing D-alanyl-D-alanine-cleaving carboxypeptidase were tested. (i) Among the heavy-atom-containing compounds examined ... [more ▼]
Several types of active-site-directed inactivators (inhibitors) of the Zn2+-containing D-alanyl-D-alanine-cleaving carboxypeptidase were tested. (i) Among the heavy-atom-containing compounds examined, K2Pt(C2O4)2 inactivates the enzyme with a second-order rate constant of about 6 X 10(-2)M-1 X S-1 and has only one binding site located close to the Zn2+ cofactor within the enzyme active site. (ii) Several compounds possessing both a C-terminal carboxylate function and, at the other end of the molecule, a thiol, hydroxamate or carboxylate function were also examined. 3-Mercaptopropionate (racemic) and 3-mercaptoisobutyrate (L-isomer) inhibit the enzyme competitively with a Ki value of 5 X 10 X 10(-9)M. (iii) Classical beta-lactam compounds have a very weak inhibitory potency. Depending on the structure of the compounds, enzyme inhibition may be competitive (and binding occurs to the active site) or non-competitive (and binding causes disruption of the protein crystal lattice). (iv) 6-beta-Iodopenicillanate inactivates the enzyme in a complex way. At high beta-lactam concentrations, the pseudo-first-order rate constant of enzyme inactivation has a limit value of 7 X 10(-4)S-1 X 6-beta-Iodopenicillanate binds to the active site just in front of the Zn2+ cofactor and superimposes histidine-190, suggesting that permanent enzyme inactivation is by reaction with this latter residue. [less ▲]Detailed reference viewed: 18 (4 ULg)
A rare complication of ophtalmic zona: spreading cerebral arteritis
; ; Fillet, Georges et al
in Acta Clinica Belgica (1984), 39(3), 159-162Detailed reference viewed: 12 (3 ULg)
Large Scale Structural Optimization by Finite Elements
in Atrek, E.; Zienkiewicz, O. C.; Ragsdell, K. M. (Eds.) et al New Directions in Optimum Structural Design (1984)Detailed reference viewed: 8 (0 ULg)
Etude du mécanisme d'action du cis-dichlorodiammineplatine (II) aux niveaux moléculaire et cellulaire, libre ou lié à des transporteurs.
Doctoral thesis (1984)Detailed reference viewed: 9 (2 ULg)
Isolation of follicular dendritic cells from human tonsils and adenoids. I. Procedure and morphological characterization.
; ; Heinen, Ernst et al
in Journal of Immunological Methods (1984), 66(2), 235-44
Follicular dendritic cells have been isolated from human tonsils and adenoids and characterized at the ultrastructural level. Follicles were dissected and digested with different hydrolytic enzymes. The ... [more ▼]
Follicular dendritic cells have been isolated from human tonsils and adenoids and characterized at the ultrastructural level. Follicles were dissected and digested with different hydrolytic enzymes. The cells were separated by sedimentation at unit gravity. By this procedure we obtained follicular dendritic cells enveloping lymphocytes with their cytoplasmic extensions in a way analogous to that described for isolated thymic nurse cells. The ultrastructural features of isolated follicular dendritic cells are similar to those observed in situ. Prolonged enzymatic action caused loss of the enveloped lymphocytes. [less ▲]Detailed reference viewed: 39 (2 ULg)
Isolation of follicular dendritic cells from human tonsils and adenoids. II. Immunocytochemical characterization.
Heinen, Ernst ; Lilet, Chantal ; et al
in European Journal of Immunology (1984), 14(3), 267-73
Follicular dendritic cells (FDC) are specialized cells found only within lymphoid follicles. They bind immune complexes and play a role in the presentation of antigen to follicular B cells and in the ... [more ▼]
Follicular dendritic cells (FDC) are specialized cells found only within lymphoid follicles. They bind immune complexes and play a role in the presentation of antigen to follicular B cells and in the generation of B cell memory. In the present report the isolation of FDC from human tonsils and adenoids is described. These isolated cells have an unusual spherical arrangement and enclose lymphocytes within extensions of their membranes. Their ultrastructural features are similar to those observed in situ. The reactivity of isolated FDC with a number of monoclonal antibodies was analyzed by immunofluorescence and by immunostaining (at the electron microscopic level) with colloidal gold. In keeping with the results of previous investigations on tissue sections IgM, IgG and IgA (but not IgD) can be detected on the surface of isolated FDC, as can C3b receptors and the FDC-associated antigen detected by monoclonal antibody R4/23. The immunoglobulins associated with FDC are mostly embedded in an electron-dense material. The majority of the lymphoid cells enclosed within the membrane extensions of FDC are of B cell type. These results suggest that isolated FDC may be suitable for further in vitro investigation of their role in the humoral immune response. [less ▲]Detailed reference viewed: 26 (0 ULg)
L’édition et le livre populaires : apparition, contenu, avatars.
Conference given outside the academic context (1984)Detailed reference viewed: 10 (2 ULg)
Testosterone metabolism and testosterone-dependent characteristics in Japanese quail.
; ; et al
in Physiology & Behavior (1984), 33(5), 817-23
In 2 independent experiments, we measured and correlated in maturing male Japanese quail the individual variations in sexual and aggressive behavior, cloacal gland size, testes weight, plasma testosterone ... [more ▼]
In 2 independent experiments, we measured and correlated in maturing male Japanese quail the individual variations in sexual and aggressive behavior, cloacal gland size, testes weight, plasma testosterone concentrations and intracellular testosterone metabolism by hypothalamus and cloacal gland. Cloacal gland area was only weakly related to plasma testosterone levels but was positively correlated with the production of active androgenic metabolites and negatively related to the production of 5 beta-reduced androgens (inactive) in the glandular tissue. Several measures of behavior were correlated with aspects of the testosterone metabolism in the anterior hypothalamus. In both experiments, the behavior of the birds was also strongly correlated with their testes weight and their cloacal gland area but weakly or not at all with their plasma testosterone levels. These studies suggest that testosterone metabolism is involved in the control of hormone action in maturing animals. [less ▲]Detailed reference viewed: 13 (0 ULg)
Shape optimal-design using B-splines
; Fleury, Claude
in Computer Methods in Applied Mechanics & Engineering (1984), 44(3), 247-267
Shape optimal design of an elastic structure is formulated using a design element technique. It is shown that Bezier and B-spline curves, typical of the CAD philosophy, are well suited to the definition ... [more ▼]
Shape optimal design of an elastic structure is formulated using a design element technique. It is shown that Bezier and B-spline curves, typical of the CAD philosophy, are well suited to the definition of design elements. Complex geometries can be described in a very compact way by a small set of design variables and a few design elements. Because of the B-splines flexibility, it is no longer necessary to piece design elements together in order to agree with the shape complexity, nor to restrict the shape variations. Moreover, the additional optimization constraints that are most often needed to avoid unrealistic designs when the shape variables are the nodal coordinates of a finite element mesh, are automatically taken into account in the new formulation. An analytical derivation of the sensitivity analysis will be established, giving rise to numerical efficiency. It will be seen that the resulting optimization problem does not involve highly nonlinear functions with respect to the shape variables, so that simple mathematical programming algorithms can be applied to solve it. Some numerical examples are offered to demonstrate the power and generality of the new approach presented in this paper. [less ▲]Detailed reference viewed: 70 (1 ULg)
Precise localization of antigens on follicular dendritic cells.
; Heinen, Ernst ; et al
in Cell & Tissue Research (1984), 235(2), 267-74
Horse-spleen ferritin or bovine serum albumin conjugated to colloidal gold (BSA-gold) were injected subcutaneously in preimmunized mice. In draining lymph nodes both antigens were located in macrophages ... [more ▼]
Horse-spleen ferritin or bovine serum albumin conjugated to colloidal gold (BSA-gold) were injected subcutaneously in preimmunized mice. In draining lymph nodes both antigens were located in macrophages or between the cytoplasmic processes of follicular dendritic cells (FDC). Some of the antigens remained trapped on FDC until day 31 after injection. Simultaneous injection of both antigens showed that they were located between the infoldings of the same FDC. These cells are thus able to retain at least two different antigens on their surface. The peculiar arrangement of ferritin between the cytoplasmic infoldings suggests that this antigen is fixed on both cell membranes by specific antibodies. The trapped immune complexes could thus stabilize the FDC membrane system. The antigen retention requires the presence of specific antibodies since BSA-gold or ferritin injected without preimmunization were not found between FDC processes. Nonantigenic materials, such as colloidal gold or carbon particles, are not trapped by FDC, except when injected in large amounts. The antigens were trapped on the surface of FDC, however unfrequently in close contact with lymphocytes. FDC might protect lymphocytes against an excess of immune complexes and act as regulators of contacts between lymphocytes and immune complexes. [less ▲]Detailed reference viewed: 8 (0 ULg)
Le statut anthropologique du Nègre dans le Dictionnaire d’Histoire Naturelle de Valmont de Bomare.
Conference (1984)Detailed reference viewed: 11 (0 ULg)
Intérêt de la mesure de la fonction du récepteur Fc des monocytes circulants et des macrophages spléniques dans les néphropathies glomérulaires de l'enfant
; ; Malaise, Michel et al
in Revue Médicale de Liège (1984), 39(8), 332-334Detailed reference viewed: 8 (3 ULg)
Analyse des classes de lipides et des acides gras de Leptomysis lingura (Sars) crustacé mysidacé. Influence des condition snutritionnelles.
Hecq, Jean-Henri ; Goffart, Anne
in Bulletin de la Société Royale des Sciences de Liège (1984), 1
See pdf file in attachmentDetailed reference viewed: 18 (4 ULg)
Interim results on the clinical effects of i.v. administered thymopentin in active rheumatoid arthritis
Malaise, Michel ; ; Hauwaert, Christian et al
in International Journal of Clinical Pharmacology, Therapy and Toxicology (1984), 4(6), 451-457
Forty-one patients with active rheumatoid arthritis entered a controlled, double-blind, randomized study; 21 received prolonged i.v. injections (10 min) of thymopentin 50 mg 3 times a week for 3 ... [more ▼]
Forty-one patients with active rheumatoid arthritis entered a controlled, double-blind, randomized study; 21 received prolonged i.v. injections (10 min) of thymopentin 50 mg 3 times a week for 3 consecutive weeks; the other 20 received placebo under the same conditions. The groups were comparable at the start of the study. Statistical tests of changes within the treatment groups after 3 weeks showed that the improvement achieved in the thymopentin group was significant (p less than 0.05 or p less than 0.01) for each clinical parameter, except for left-hand grip strength. On the other hand, no significant improvement was observed for any parameter except morning stiffness in the patients on placebo. The intergroup comparison showed significant differences, favouring thymopentin over placebo treatment, in the Ritchie index, scores for swollen joints, assessment of severity of pain and scores for changes in the activity of the disease. Only minor side-effects were experienced in the two treatment groups. The present placebo-controlled double-blind study confirms the previous positive results achieved in open studies, i.e., the beneficial therapeutic effect of prolonged i.v. injections of thymopentin in patients with severe rheumatoid arthritis observed after 3 weeks of therapy. The drug appears to be safe at the dose regimen used. [less ▲]Detailed reference viewed: 6 (0 ULg)
Fetal calf serum-mediated inhibition of neurite growth from ciliary ganglion neurons in vitro
; ; et al
in Journal of Neuroscience Research (1984), 12(1), 29-39Detailed reference viewed: 11 (0 ULg)
High-Yield Synthesis of a (3H)Ethylenediamine Ditetrodotoxin Derivative
; ; Grandfils, Christian et al
in Analytical Biochemistry (1984), 139Detailed reference viewed: 10 (3 ULg)
Estradiol contributes to the postnatal demasculinization of female Japanese quail (Coturnix coturnix japonica).
Balthazart, Jacques ;
in Hormones and Behavior (1984), 18(3), 287-97
Two experiments were performed to characterize the process of postnatal demasculinization in Japanese quail. In the first experiment, it was shown that estradiol (E2) can complete female demasculinization ... [more ▼]
Two experiments were performed to characterize the process of postnatal demasculinization in Japanese quail. In the first experiment, it was shown that estradiol (E2) can complete female demasculinization during the first 4 weeks of life. By contrast, E2 did not demasculinize sexual behavior and cloacal gland in neonatally castrated males. Neonatally gonadectomized females preferentially performed mount attempts when tested in their home cage by comparison to a test arena. In Experiment 2, E2 Silastic implants (40-mm) maintained full copulatory behavior in castrated males but not in females. This large dose of E2 did not demasculinize adult sexually active birds (males or females) even if treatment lasted for 1 month. It is concluded that E2 can demasculinize sexual behavior only in females and only if treatment is performed in very young birds. [less ▲]Detailed reference viewed: 16 (1 ULg)