Identification of neutrophil chemotactie factors in bronchoalveolar lavage fluid of asthmatic patients

Background Although neutrophils have been implicated in bronchial asthma, the mechanism(s) which bring these cells into the airways is poorly understood. Objective To investigate the presence and identity of neutrophil chemotactic factors in bronchoalveolar lavage (BAL) fluid from atopic asthmatic subjects. Method BAL fluid was obtained from 13 subjects (seven asthmatics and six normals). aged 19 to 60 yr, at bronchoscopy. Separation of neutrophil chemotactic activity (NCA) was achieved by FPLC cation exchange chromatography. Fractions were collected and assayed for chemotaxis multiwell micro-chemotaxes chambers using polycarbonate filters, for the complement peptide C5a/C5a des Arg by radioimmunoassay (RIA) and for interleukin-8 (IL-8) by ELISA. Results NCA was found in FPLC fractions of BAL samples in four out of seven asthmatics and each of these subjects had at least three similar peaks of NCA. The major peak of NCA was found to contain immunoreactive C5a/C5a des Arg and chemotaxis. In response to this NCA could be blocked by desensitization of the neutrophils with recombinant C5a. Purified serum derived C5a/C5a des Arg was found to have altered chromatographic properties when added to BAL fluid; this suggested that BAL fluid contained proteins which interacted with the C5a/C5a des Arg. Immunoreactive IL-8 (iIL-8) was also detected but its concentration or chemical form was insufficient to induce neutropbil chemotaxis. Conclusion This study demonstrates that bronchial asthmatic lavage fluid contains C5a/C5a des/Arg and iL-8, together with other as yet unidentified factors which may contribute to neutropbil recruitment in this disease.     

大白鼠游泳输出功测定仪的研制和疲劳方程Y＝A＋B／T的建立

研制了可以直接连续测量大鼠游泳输出功率的仪器，建立了一个理想的动物模型，通过分析对功率曲线进行函数拟合，得出了代表疲劳发生、作功能力下降的双曲线方程，通过分析衰竭时间和功、功率等参数的关系提出了衰竭阈概念。     

Genomic imprinting and its relevance to genetic diseases

Summary Genomic imprinting is a biological phenomenon determined by an evolutionally acquired, underlying system that may control harmonious development and growth in mammals. It is also relevant to some genetic disorders in man. In this article, lines of biological evidence of imprinting, characteristics of the mouse and human imprinted genes, and findings and mechanisms on the occurrence of several human imprinting disorders are reviewed.     

Expression of high- and low-affinity receptors for C3a on the human mast cell line,HMC-1

The proteolytic cleavage product of complement component 3, (C3a), like C4a and C5a, is a potent anaphylatoxin and induces the production of inflammatory mediators in phagocytes. Notably, mast cells respond to C3a with the release of vasoactive substances, including histamine. We have examined the function and receptor binding of C3a in a human leukemic mast cell line, HMC-1. Similar to chemoattractant agonists in leukocytes, C3a induced rapid cytosolic free calcium concentration increases in HMC-1 cells. EGTA did not diminish this response, indicating that mobilizable Ca²⁺ was from intracellular stores. Receptors for C3a in HMC-1 cells couple in part to Bordetella pertussis toxin-sensitive G-proteins and, therefore, appear to belong to the family of serpentine receptors that require G-proteins for signal transduction. HMC-1 cells express two types of C3a receptors, C3aR1 and C3aR2, that were shown to bind ¹²⁵I-C3a with high-(K_d1 = 2.1–4.8 nM) or low-affinity (K_d2 = 30–150 nM), and both receptors are expressed at high level: 3 × 10⁵–6 × 10⁵ C3aR1/cell and 5 × 10⁵–2.3 × 10⁶ C3aR2/cell. Results from cross-linking experiments with ¹²⁵I-C3a fully agree with the presence of two different classes of C3a receptors in HMC-1 cells. Two membrane proteins with apparent molecular masses of 54–61 kDa (p57) and 86–107 kDa (p97) could be covalently modified with ¹²⁵I-C3a, and this cross-linking was inhibited with an excess of unlabeled C3a. Many of the known agonists for leukocytes including 13 chemokines (IL-8, NAP-2, GROα, ENA-78, IP10, PF4, MCP-1, 2 and 3, RANTES, MIP-1α, MIP-1β and 1309), three neuropeptides (neuropeptide Y, somatostatin and calcitonin), as well as C5a, did not activate HMC-1 cells, indicating that C3a is one of a few protein ligands for which this cell line expresses specific receptors. The apparent selectivity for C3a and the abundant expression of C3a receptors make the HMC-1 cell line an excellent choice for the cloning of the receptor genes.     

Inhibition of interleukin-6 synthesis in an animal model of septic shock by anti-C5a monoclonal antibodies

The complement activation fragment C5a was recently shown to induce interleukin (IL)-6 synthesis by peripheral blood mononuclear cells. To understand better the role of C5a in cytokine regulation in vivo, we investigated the effects of complement depletion by cobra venom factor (CVF) or of anti-C5a monoclonal antibodies (mAb) on IL-6 generation in an animal model of septic shock. Complement-depleted pigs which were subsequently challenged with Escherichia coli generated significantly (p < 0.05) less IL-6 during the 6-h observation period than complement-sufficient controls. To address specifically the role of C5a in IL-6 regulation, we produced a C5a(57–74) peptide-specific mAb (T13/9) which neutralizes the bioactivity of porcine C5a. The mAb T13/9 does not crossreact with the precursor protein C5. The pretreatment of pigs with anti-C5a mAb T13/9 prior to the induction of sepsis resulted in a decrease of over 75 % in serum IL-6 bioactivity compared to control animals (p < 0.0001). These results indicate a role for C5a in the modulation of IL-6 synthesis in Gram-negative bacteremia.     

Marden-Walker syndrome: case report, literature review and nosologic discussion

Schrander-Stumpel C, de Die-Smulders C, de Krom M, Schyns-Fleuren S, Hamel B, Jaeken D, Fryns J-P. Marden-Walker syndrome: case report, literature review and nosologic discussion.
Clin Genet 1993: 43: 303–308. © Munksgaard, 1993
The Marden-Walker syndrome is characterized by psychomotor retardation, a mask-like face with blepharophimosis, micrognathia and a high-arched or cleft palate, low-set ears, kyphoscoliosis and joint contractures. We report on a male patient with the clinical features of the syndrome. In addition, he had a Dandy-Walker malformation with hydrocephalus and vertebral abnormalities. During pregnancy, there were feeble fetal movements and polyhydramnios. We propose that Marden-Walker syndrome is one of the etiologic possibilities in children with the heterogeneous fetal a(hypo)kinesia deformation sequence (FADS). Differential diagnosis is discussed. The etiology is probably heterogeneous.     

Analysis of the mechanism of lipoprotein(a) assembly

We have assessed the ability of a battery of purified recombinant apolipoprotein(a) (r-apo(a)) derivatives to bind to immobilized low-density lipoprotein (LDL) by ELISA. Removal of the apo(a) kringle IV type 8 and type 9 sequences dramatically reduced apo(a) binding to LDL. The binding of apo(a) to LDL was effectively inhibited by arginine, lysine, the lysine analogue ε-aminocaproic acid and proline; comparable inhibition was observed using the 17K and KIV_5–8 r-apo(a) derivatives, suggesting a direct role for sequences contained in the latter species in mediating the initial non-covalent interactions which precede specific disulfide bond formation. We also determined that r-apo(a) binds directly to a synthetic apoB peptide spanning amino acid residues 3732–3745; this interaction appeared to be mediated by sequences present in apo(a) kringle IV types 8 and 9, and could be inhibited by arginine, lysine and proline. The results of this study indicate that the efficiency of Lp(a) assembly is a direct function of the initial non-covalent interactions between apo(a) and LDL; in addition, these studies suggest that Cys3734 in apoB mediates covalent linkage with apo(a) by virtue of the ability of the apoB sequences surrounding this residue to directly interact with apo(a) KIV type 9.