[Study on modulation effect of qi regulating and blood activating drugs on mechanism of immunity and hemorrheology in stressed rats].

OBJECTIVE: To explore the modulation effect of Chinese herbal medicines for Qi regulating and blood activating (QRBA) on mechanism of immunity and hemorrheology in stressed rats. METHODS: The influence of QRBA on plasma noradrenaline (NA), proliferation of splenic cells and hemorrheologic properties were observed in stressed rats. RESULTS: The Chinese herbal medicines for soothing Liver to regulate Qi, activating blood circulation to remove stasis and QRBA drugs could antagonize in various degrees the changes caused by stress. Among them QRBA drugs was the best, it could reduce the level of plasma NA (P < 0.01), modulate the blood hyperviscosity induced by exogenous NA (P < 0.05) and enhance proliferation of splenic cells (P < 0.01) in rats. CONCLUSION: QRBA drugs strengthen immune function and restore hemorrheologic properties by reducing NA content in organism.

[Modulation of tonic herbs on the immune cell inhibition in stressed model animal and its possible mechanism].

OBJECTIVE: To observe the effect of tonic herbs on the immune cell proliferation in stressed mice. METHODS: A model of stressed mice was built to observe the effect of such tonic herbs as Tusizi, Chuanduan; Nüzhenzi, Gouqizi on the calcium concentration in cytoplasm in the process of immune cell reproduction, as well as on the membrane fluidity of splenetic lymphocytes, IL-2, IL-2R and cell period. RESULTS: The tonic herbs could improve the proliferation ability of spleen lymphocyte in the stressed mice, reduce the calcium concentration, and recover the fluidity of cell membrane. They could also improve the activity of IL-2 and increase the amount of IL-2R cell(P < 0.01). The combination of the four tonic herbs proved more effective, facilitating the cell into DNA synthetic period and reducing the retention period in G0/G1 (P < 0.01). CONCLUSION: Tonic herbs can modulate the reproductive function of the spleen lymphocyte and relieve the unfavorable response of the stress on the organism.

Fibrillin containing elastic microfibrils support platelet adhesion under dynamic shear conditions.

The vascular subendothelium contains macromolecular structures called microfibrils. Type VI collagen is one protein found in microfibrils that supports platelet adhesion and aggregation and we have previously evaluated the roles of platelet receptors and vWf involved in these processes under physiological shear conditions. Here we investigate the ability of fibrillin containing elastic microfibrils to support mural thrombus formation. Our results show that elastic microfibril surfaces support platelet adhesion under low shear conditions at a level similar to collagen VI tetramers. However, the degree of aggregation on the elastic microfibril surface is much higher. Both adhesion and aggregation were shown to be mediated by the GPIIb-IIIa platelet receptor. Elastic microfibrils do not support the formation of mural thrombi under high shear conditions. These results suggest roles for both collagen VI and fibrillin containing elastic microfibrils in modulating the platelet response to blood vessel injury.

Alignment of fibrillin molecules in elastic microfibrils is defined by transglutaminase-derived cross-links.

Microfibrils were extracted from human amnion in the form of a beaded filament and analyzed for the presence of transglutaminase-derived cross-links using acrylonitrile derivatization. The cross-link structure was isolated from protease hydrolysates of beaded filaments and identified as a phenylthiocarbamyl amino acid derivative by comparison to a standard. Acid hydrolysis of the isolated cross-link gave the expected lysine and glutamic acid in a 1:1 ratio. The beaded filaments were also treated with trypsin to produce a fraction that contained the bead structure and a fraction containing fragments of the interbead filaments. Cross-links were detected in the interbead filaments but not in the beads. A large tryptic peptide that contained a cross-link was isolated and sequenced. The two amino acid sequences obtained identified both of the cross-linked molecules as fibrillin-1 and enabled the approximate localization of the cross-link sites within the molecule. The locations of cross-link sites on two adjacent molecules fixed the relative positions of fibrillin monomers within the microfibrils, providing insight into the spatial organization of fibrillin within the elastic microfibrils.

Calcium binding, hydroxylation, and glycosylation of the precursor epidermal growth factor-like domains of fibrillin-1, the Marfan gene protein.

The extracellular matrix protein fibrillin-1 is a major component of elastic microfibrils, which are complex assemblies of several proteins and are found in most connective tissues, frequently associated with elastin. Fibrillin-1 contains 43 precursor epidermal growth factor-like (pEGF) domains that have a consensus sequence for calcium binding. The calcium binding potential of a fibrillin-1 pepsin fragment (PF2) was quantitatively analyzed using microvolume equilibrium dialysis. Peptide sequence data and pepsin fragment size determination indicate that PF2 contains seven pEGF domains, each with the calcium binding consensus sequence. Scatchard plot analysis of the calcium binding data shows that PF2 has six to seven high affinity binding sites with a Kd = 250 microM at pH 7.5. There is a second overlapping consensus sequence in the pEGF domains for beta-hydroxylation of a specific Asp/Asn residue. Five partially hydroxylated Asn residues have been identified by protein sequence analysis of fibrillin-1 fragments. This is the first demonstration of this modification in a connective tissue protein. The calcium binding consensus sequence also contains a conserved Ser residue with an apparently novel modification, which causes the Ser residue to behave like an Asp residue during protein sequencing. Marfan syndrome, a heritable disorder of connective tissue, is known to be associated with mutations in the FBN1 gene. Most of these mutations have been found in pEGF domains, frequently substituting Cys for another amino acid, destroying the pEGF motif secondary structure along with its calcium binding potential. Other mutations cause the substitution of single amino acids in the calcium binding consensus sequence, which could affect calcium binding but also the hydroxylation of Asp/Asn residues or the modification of Ser residues.

Amino acid sequence of the N-terminal aggregation and cross-linking region (7S domain) of the alpha 1 (IV) chain of human basement membrane collagen.

The amino acid sequence of the 216-residue-long N-terminal aggregation and cross-linking 7S domain of the alpha 1 (IV) chain of human placental basement membrane collagen is presented. The N terminus of the alpha 1 (IV) chain starts with a non-triple-helical region, which is at least 15 residues long and contains four cysteine and two lysine residues as putative cross-linking sites. This segment is followed by a 120-residue-long triple helical region, which contains the unusual occurrence of a cysteine residue in the Xaa position of a Gly-Xaa-Yaa triplet. Since individual molecules in the 7S domain are associated in an antiparallel manner, this cysteine probably aligns with one of the four cysteines in the amino-terminal end of an adjacent molecule, forming an intermolecular disulfide bridge. The length of the overlap of two adjacent molecules is estimated to be about 110 residues. The triple helix adjacent to the overlap zone is interrupted by a 10-residue-long non-helical area, which is probably responsible for the flexible region of the molecules in the neighbourhood of the overlap zone observed in the electron microscope. The mode of aggregation of the 7S domain, the formation of intermolecular cross-links as well as the relatively high stability of this region against proteolytic attack are discussed in the light of the elucidated amino acid sequence.