The distribution of Mas-related G protein-coupled receptor A in cerebrospinal fluid-contacting nucleus of normal rats and its up-regulation in neuropathic pain / 生理学报

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.

In vitro anti-oxidant property of protein-A of Staphylococcus aureus.

Protein-A (PA) is a cell-surface glycoprotein of S. aureus Cowan I with immunomodulatory and anti-tumor activities, and ability to ameliorate cyclophosphamide and carbontetrachloride (CCl4) induced toxicity in rodents. The likely mechanism of this effect appears to be the anti-oxidant property of PA, evidenced in the present study by inhibition of CCl4 and Fe2-ascorbate induced lipid peroxidation in rat liver homogenates and inhibition of deaminative-oxidative degradation of L-glutamate into 2-thiobarbituric acid reactive products in a constituted chemical system. The anti-oxidant property of PA seem to arise from its molecular characteristics and the ability to interact with a superoxide derived free-radical species without any affinity for superoxide anion, hydroxyl radical and singlet oxygen species.

Isolation of horse IgG with protein A

Horse immunoglobulins were obtained from normal defatted with dextran sulfate and precipitated with ammonium sulfate. Eight mg of this preparation was submitted to affinity chromatography with protein A-Sepharose CL-4B. Low temperature (4-C) and a starting buffer at pH 8.0 were conditions required for all IgG subclasses to bind to protein A, even those with low affinity. The IgGs bound to protein A were eluted with glycine buffer at pH 2.8. The yield was about 90%. Its suggested that isolated IgG, instead of whole Igs, be used in serum therapy, reducing the amount of Igs and diminishing serum-related reactions

Chronic myelogenous leukemia: alterations in red cell membrane band 3 and increased IgG binding.

Chronic myelogenous leukemia (CML) is a hematologic malignancy arising from an abnormal hemopoietic stem cell. Our earlier studies have identified defects in spectrin tetramer formation and organization of cytoskeletal proteins (Basu et al., Biochim. Biophys. Acta 1988, 121-126); and decreased ankyrin binding to ankyrin-depleted vesicles in CML patients. These may lead to clustering of band 3 and increased binding of autologous IgG. This has now been explored by studying the binding of 125I-protein A to normal and CML erythrocytes. There is increased binding of 125I-protein A in CML erythrocytes compared to normal erythrocytes. Since binding of autologous IgG is responsible for removal of erythrocytes from the circulation, the above findings suggest that CML erythrocytes are likely to be prematurely removed from the circulation, accounting for anemia.

Estudio sobre las condiciones de fijación de IgG a la proteína A de Staphylococcus aureus / The conditions of IGG fixation to the protein A of Staphylococcus aureus

Distintas cepas de Staphylococcus aureus tienen una proteína de membrana denominada "proteína A", la que fija IgG1, IgG2, e IgG4 humanas y la IgG de otras especies animales. La unión tiene lugar mediante el fragmento Fc. Debido a esta propiedad, el Staphylococcus aureus, que sintetiza proteína A, ha sido empleado para la adsorción específica de anticuerpos contra diferentes bacterias y utilizados para el diagnóstico microbiológico. Teniendo en cuenta las ventajas de este método, se estudian en este trabajo las condiciones físico-químicas que regulan la fijación de IgG a la proteína A de 33 cepas de Staphylococcus aureus coagulasa positivas. De acuerdo con estos resultados se propone un método adecuado para la unión de la IgG a la proteína A bacteriana