This study was aimed to observe the distribution of Mas-related G protein-coupled receptor A (MrgA) in cerebrospinal fluid (CSF)-contacting nucleus of normal rats and its expression in neuropathic pain, and to provide morphological evidence for CSF-contacting nucleus to participate in neuropathic pain. The model of neuropathic pain with chronic constriction injury (CCI) of the sciatic nerve was made in Sprague-Dawley rats. The thermal withdrawal latency (TWL) and mechanical withdrawal threshold (MWT) were measured. The expressions of MrgA in the CSF-contacting nucleus were examined by double labeling with immunofluorescent staining. The results showed that on the 5th, 7th, 10th and 14th days, the values of MWT and TWL in CCI group were all lower than those in sham group (P < 0.05). MrgA was found to be distributed in CSF-contacting nucleus of normal rats; and the expression was markedly up-regulated in rats at the peak of neuropathic pain. Our data suggest that CSF-contacting nucleus may participate in neuropathic pain through the MrgA-mediated signaling pathway.
Animals ; Neuralgia ; Rats ; Rats, Sprague-Dawley ; Receptors, G-Protein-Coupled/metabolism* ; Staphylococcal Protein A/metabolism* ; Up-Regulation

Background: Triiodothyronine(T3) is a hormone secreted from thyroid gland which exerts a stimulating effect on metabolism. The disorder of thyroid system brings about several serious diseases like hypothymidism or hyperthyroidism. Therefore, the determination of T in blood is very important on monitoring thyroid function. Methods: Rabbit anti-T3 antibody was generated by immunization of T-BSA as an immunogen and purified hom antisera using Affi-gel protein A kit. The titer and specificity of purified antibody were characterized. To detect T3, competitive ELISA was performed using anti-T3 antibody and T3-HRP conjugate which was synthesized by glutaraldehyde method. The sensitivity and precision assay wer~e deterrnined and compared with that of RIA. Results: The titer of purified anti-T3 antibody was about 1:100 and the optimal dilution of T3- HRP conjugate was 1:1000. When the standard curve was constructed by ELISA, its sensitivity was about 0.5ng/ml. The eoefficient variations of intra- and inter-assay were 4.9~9.3% and 7.5~13.8%, respectively. The results obtained by ELISA and RIA correlated well with each other(n =50, r= 0.97), The linear regression equation was y= 1.09*0.08(P<0.01). Conclusion: We successfully developed a method for the measurement of T3 on ELISA which was based on competitive reaction between antigen(T3) and enzyme labeled antigen(T3-HRP). These results demonstrated that competitive ELISA is a convenient, fast, reproducible and aecurate method for the determinstion of T in serum and can be used as practical alternative to RIA.
Enzyme-Linked Immunosorbent Assay ; Glutaral ; Hyperthyroidism ; Immune Sera ; Immunization ; Linear Models ; Metabolism ; Methods ; Sensitivity and Specificity ; Staphylococcal Protein A ; Thyroid Gland ; Triiodothyronine

Pulmonary surfactant prevents alveolar collapse by reducing alveolar surface tension and aids gaseous exchange in the lung. Since inadequate production of pulmonary surfactant is a key etiological process in ARDS, surfactant may play an important role in pathogenesis of ARDS. To provide a clue for establishing pathological mechanism of post-traumatic or neurogenic ARDS, we studied the influence of the vagal innervation on pulmonary surfactant metabolism. A total of 20 S-D rats (about 230 gm wt. each) were divided into two conditions: normal control and vagotomized groups. The vagotomized rats were subdivided into 3 hours, 8 hours and 24 hours groups. To preserve the superior cervical cardiac branches, both vagus nerves were cut at the lowest part of the carotid triangle. Cannula for adequate respiration and suction was fitted into the trachea. The lung tissue were processed for H&E, Masson's trichrome, Immunohistochemistry using anti-surfactant protein A (SP-A) and .anti-prosurfactant protein C (ProSP-C). The results were as follows; 1. The lungs of the vagotomized rats showed alveolar edema, fibrosis with infiltration of inflammatory cells and hyaline membrane formation. 2. In the lungs of the vagotomized rats, SP-A and ProSP-C immunoreactivity was decreased in proportion to postoperation time. Consequently, it can be postulated that autonomic disturbances caused by vagal interruption may induce ARDS-like pulmonary damage by modulating alveolar surfactant protein metabolism and by evoking the secondary inflammatory processes.
Animals ; Catheters ; Edema ; Fibrosis ; Hyalin ; Immunohistochemistry ; Lung ; Membranes ; Metabolism ; Protein C ; Pulmonary Surfactants ; Rats ; Respiration ; Staphylococcal Protein A ; Suction ; Surface Tension ; Trachea ; Vagotomy* ; Vagus Nerve

Protein A and protein G are two well-defined immunoglobulin (Ig)-binding proteins (IBPs), which show affinity for specific sites on Ig of mammalian hosts. Protein A and protein G contained several highly homologous IgG-binding domains which had been demonstrated to have function to bind to IgG. Whether combinations of Ig-binding domains of various IBPs could produce useful novel binding properties remains interesting. We constructed a combinatorial phage library which displayed randomly-rearranged A, B, C, D and E domains of protein A, B2 and B3 domains of protein G. Four rounds molecular evolution of this library directed by all four human IgG subclasses respectively generated a common arrangement of D-C respectively which didn't exist in SpA. The dynamic loss of control phages and increase of the phages displaying two or more binding domains, especially the selective enrichment of D-C and strict selection of its linking peptides demonstrated the efficient molecular evolutions and the significance of the selected D-C arrangement. The phage binding assays confirmed that D-C possessed a binding advantage with four human IgG subclasses compared to SpA. In this work, a novel combination of Ig-binding domains, D-C, was obtained and presented the novel Ig binding properties which provided a novel candidate molecule for the purification, production and detection of IgG antibodies and a new approach for the further study of structures and functions of IBPs.
Amino Acid Sequence ; Antibody Specificity ; Bacterial Proteins ; immunology ; metabolism ; Binding Sites ; Binding, Competitive ; Evolution, Molecular ; Immunoglobulin G ; immunology ; metabolism ; Molecular Sequence Data ; Peptide Library ; Sequence Alignment ; Staphylococcal Protein A ; immunology ; metabolism

To screen an efficient recombinant Staphylococcus aureus protein A (SpA) for preparing matrix for affinity purification of immunoglobulin G (IgG), a genetic engineering approach was used to obtain monomer, two, three, four and five tandem repeats genes of the Z domain of SpA, then the genes were cloned into expression vector pET-22b and subsequently expressed in Escherichia coli BL21 (DE3). After induction with lactose, the target proteins were purified by Ni2+ affinity chromatography. The proteins with two, three, four and five tandem repeats of the Z domain were then coupled to CNBr-activated Sepharose 4B as an affinity chromatography matrix for affinity purification of human IgG. Furthermore, the differences in protein yield and IgG-binding capacity at different recombinant proteins were analyzed. The target proteins with monomer and tandem repeats of the Z domain had an effective expression in the genetic engineering bacteria. IgG could be specifically absorbed from human plasma by affinity chromatography. The protein yield and amount of IgG absorption of per mole protein could be improved by increasing the tandem repeats number of the Z domain. Compared with other tandem repeats, four tandem repeats of the Z domain exhibited more protein yield (160 mg/10 g wet cells) and higher level of IgG absorption (34.4 mg human IgG/mL gel). Therefore, four tandem repeats of the Z domain is more suitable for preparing matrix for affinity purification of IgG.
Adsorption ; Bacterial Proteins ; biosynthesis ; genetics ; Chromatography, Affinity ; methods ; Cloning, Molecular ; Escherichia coli ; genetics ; metabolism ; Humans ; Immunoglobulin G ; isolation & purification ; metabolism ; Recombinant Proteins ; biosynthesis ; genetics ; metabolism ; Staphylococcal Protein A ; biosynthesis ; genetics ; Tandem Repeat Sequences

BACKGROUNDSensitized recipients have a high risk of immunological graft loss due to hyperacute rejection and/or accelerated acute rejection. The presence of major histocompatibility complex class I-related chain A (MICA) antibodies has also been described associated with an increased rate of kidney-allograft rejection. The aim of this study was to describe the expression of MICA antibodies in sensitized recipients of renal transplantation and evaluate its influence on the kidney transplantation recipients.

METHODSA total of 29 sensitized recipients were included in this study. All patients received the MICA antibodies detection before and after protein A immunoadsorption. Panel reactive antibody (PRA), HLA-matches, acute rejection and postoperative one to four-week serum creatinine level were also collected and analyzed, respectively. No prisoners were used in this study.

RESULTSEight patients (27.6%) in all 29 sensitized recipients expressed the MICA antibodies but did not show higher acute rejection rate than the non-expressed patients (3/8, 37.5% vs. 8/21, 38.1%; P = 1.000). Recipients with PRA > 40% showed higher expression levels of MICA antibodies than the recipients with PRA < 40% (7/16, 43.8% vs. 1/13, 8.3%; P = 0.044). HLA mismatch did not have any effect on the expression of MICA antibodies (P = 1.000). MICA antibodies positive group had higher serum creatinine level than the control in postoperative one week ((135.4 ± 21.4) µmol/L vs. (108.6 ± 31.6) µmol/L, P = 0.036), but no significant difference in postoperative four weeks ((89.0 ± 17.1) µmol/L vs. (77.1 ± 15.9) µmol/L, P = 0.089). MICA antibodies decreased significantly after protein A immunoadsorption.

CONCLUSIONSMICA antibodies increase in the sensitized recipients, which have significant effects on the function of allograft in early postoperative period. Protein A immunoadsorption can decrease MICA antibodies effectively in sensitized recipients.

Adult ; Antibodies ; immunology ; metabolism ; Antilymphocyte Serum ; therapeutic use ; Cell Line ; Female ; Histocompatibility Antigens Class I ; immunology ; Humans ; Immunosorbents ; chemistry ; Immunosuppressive Agents ; therapeutic use ; Kidney Transplantation ; immunology ; Male ; Staphylococcal Protein A ; chemistry

OBJECTIVETo investigate the effects of extracellular signal-regulated kinase (ERKs) inhibition by AG126 on tissue tumor necrosis factor-alpha (TNF-alpha) expression and multiple organ dysfunction in rats with postburn Staphylococcus aureus sepsis and its potential signal regulating mechanism.

METHODSTo reproduce postburn sepsis model, male Wistar rats were inflicated with 20% total body surface area third-degree scald followed by Staphylococcus aureus challenge. 34 rats were randomly divided into four groups as follows: normal control group (n = 6), scald control group (n = 6), postburn sepsis group (n = 12), and AG126 treatment group (n = 10). Tissue samples from the liver, kidneys and lungs were collected to determine phosphorylated ERKs by Western blot analysis, and TNF-alpha mRNA expression as well as its protein levels.

RESULTSIt was revealed that phosphorylated ERKs in the liver, lungs, and kidneys from postburn septic animals were up-regulated rapidly at 0.5 - 2.0 hours, being 1.94-fold (P < 0.05), 2.86-fold (P < 0.01), and 1.41-fold at 2.0 hours compared to normal controls, respectively. Treatment with AG126 could significantly reduce phosphorylated ERKs in lung tissue by 70.6% (P < 0.01) at 2.0 hours postburn sepsis, and almost completely inhibited ERKs activation in the liver and kidneys at various time points. Meanwhile, both TNF-alpha mRNA and protein expressions in the liver, lungs, and kidneys were significantly decreased in AG126-treated group following septic challenge (P < 0.05 or 0.01). In addition, 2.0 hours after Staphylococcus aureus infection, treatment with AG126 markedly improved hepatic and renal function parameters, including serum ALT, AST, Cr, as well as BUN levels (P < 0.05 or 0.01), together with significant decrease in pulmonary myeloperoxidase activity, compared to those without AG126 treatment.

CONCLUSIONThese data suggested that ERKs signal transduction might be involved in the pathogenesis of systemic inflammatory response and multiple organ dysfunction in postburn gram-positive bacterial sepsis. Early treatment with AG126 could significantly down-regulate TNF-alpha mRNA expression as well as protein levels in vital organs and attenuate multiple organ dysfunction induced by scald injury combined with Staphylococcus aureus challenge.

Animals ; Blotting, Western ; Burns ; complications ; Enzyme Inhibitors ; pharmacology ; Gene Expression ; drug effects ; Kidney ; metabolism ; physiopathology ; Liver ; metabolism ; physiopathology ; Lung ; metabolism ; physiopathology ; Male ; Mitogen-Activated Protein Kinases ; antagonists & inhibitors ; metabolism ; Multiple Organ Failure ; metabolism ; physiopathology ; RNA, Messenger ; genetics ; metabolism ; Random Allocation ; Rats ; Rats, Wistar ; Staphylococcal Infections ; etiology ; physiopathology ; Tumor Necrosis Factor-alpha ; genetics ; metabolism ; Tyrphostins ; pharmacology

Base Sequence ; Binding Sites, Antibody ; Biochemistry ; methods ; Electrophoresis, Polyacrylamide Gel ; Enzyme-Linked Immunosorbent Assay ; Escherichia coli ; genetics ; Genetic Vectors ; Immunoglobulin Fc Fragments ; genetics ; metabolism ; Immunoglobulin G ; genetics ; metabolism ; Ligands ; Molecular Sequence Data ; Plasmids ; Protein Binding ; Recombinant Fusion Proteins ; genetics ; isolation & purification ; Staphylococcal Protein A ; genetics ; metabolism