ABSTRACT
Neuropathic pain induced by sciatic nerve injury not only causes peripheral dysfunctions but also affects the cortical and subcortical regions of the brain. It is still unknown whether neuropathic pain could relate to behavioral and neurochemical alterations in the central nervous system. This paper deals with the effect of peripheral neuropathic pain on mechanical allodynia, neuropeptide levels, neuropeptide-degrading enzyme activities, and microglial cells in the brain regions of rats by applying chronic constriction injury, a partial sciatic nerve injury. We examined the possible protection effect on the allodynia and changes in levels of neuropeptides and microglial activation in chronic constriction injury of the rat brain by memantine. On 4 days after chronic constriction injury, the induction of mechanical allodynia was suppressed by memantine treatment. Reductions in the substance P in the hypothalamus and somatostatin in the periaqueductal gray of chronic constriction injury rat brain were reversed by memantine. This suggests the role of these neuropeptides in pain information processing in the brain. Immunohistochemical experiments revealed that the expression of CD11b, a marker protein of microglia, was increased in the hypothalamus and periaqueductal gray in the chronic constriction injury rat brain as compared with the controls, and memantine treatment could suppress the activation of microglia, suggesting the involvement of microglia in pain mechanism. The present behavioral, biochemical, and immunohistochemical studies demonstrated that peripheral neuropathic pain affects the neuropeptide levels and microglial activation in the brain regions, and these events described above may play an important role in neuropathic pain pathogenesis.
Subject(s)
Brain/drug effects , Memantine/pharmacology , Microglia/drug effects , Neuralgia/drug therapy , Neuropeptides/drug effects , Peripheral Nervous System Diseases/drug therapy , Analgesics/pharmacology , Analgesics/therapeutic use , Animals , Brain/metabolism , Brain/physiopathology , CD11 Antigens/metabolism , Disease Models, Animal , Excitatory Amino Acid Antagonists/pharmacology , Excitatory Amino Acid Antagonists/therapeutic use , Hyperalgesia/drug therapy , Hyperalgesia/metabolism , Hyperalgesia/physiopathology , Hypothalamus/drug effects , Hypothalamus/metabolism , Hypothalamus/physiopathology , Male , Memantine/therapeutic use , Microglia/metabolism , Neuralgia/metabolism , Neuralgia/physiopathology , Neuropeptides/metabolism , Periaqueductal Gray/drug effects , Periaqueductal Gray/metabolism , Periaqueductal Gray/physiopathology , Peripheral Nervous System Diseases/metabolism , Peripheral Nervous System Diseases/physiopathology , Rats , Rats, Wistar , Sciatic Neuropathy/drug therapy , Sciatic Neuropathy/metabolism , Sciatic Neuropathy/physiopathology , Somatostatin/metabolism , Substance P/metabolismABSTRACT
A new sensitive and automated chemiluminescent assay was developed for the quantitative determination of hepatitis C virus (HCV) core antigen (Ag) in human sera or plasma: the Abbott ARCHITECT HCV Ag test. The assay sensitivity was determined by testing 10 commercial HCV seroconversion panels. Without exception, a positive result for HCV core Ag was observed before anti-HCV detection, resulting in an average reduction in the period between exposure and detection of 35.8 days. Both HCV core Ag and HCV RNA were detected in the panels at the same time, indicating equivalent sensitivity and detectability. A total of 197 HCV specimens comprising genotypes 1a, 1b, 2a, 2b, 3a, 3k, 4a, 5a and 6a were evaluated. Among these, 196 (99.5%), 191 (97%) and 193 (98%) were reactive using the HCV Ag, the immunoradiometric HCV Ag and the Amplicor HCV Monitor 2 assays, respectively. A comparison with the Amplicor HCV Monitor 2 showed a correlation coefficient (r) of 0.74. The specificity of the assay was established at 99.8% by testing 5403 specimens from US volunteer blood donors, hospitalized patients and individuals with medical conditions unrelated to HCV infection, in addition to specimens containing potentially interfering substances.
Subject(s)
Antigens, Viral/blood , Automation/methods , Hepacivirus/immunology , Luminescent Measurements/methods , Microspheres , Viral Core Proteins/blood , Humans , Immunoassay/methods , Plasma/chemistry , RNA, Viral/blood , Sensitivity and Specificity , Serum/chemistryABSTRACT
BACKGROUND/AIMS: Although serum assays for pro-gastrin-releasing peptide (ProGRP) assays have been commercially available in Japan for several years, the stability of ProGRP in serum and plasma has not been well documented. We investigated the stability of ProGRP in serum and plasma with fresh and stored (frozen) specimens, as well as the cause of the observed instability in serum. METHODS/RESULTS: ProGRP concentrations in fresh serum were decreased by 6-28% after room temperature storage for 2 h and by 8-32% after 2-8 degrees C storage for 24 h. The average change in ProGRP concentrations in fresh plasma was within +/-10% of baseline for more than 4 h at room temperature and for more than 24 h at 2-8 degrees C. The incubation of a serine protease, thrombin (activated blood coagulation factor II), in a buffer solution containing ProGRP caused decreases in ProGRP concentrations. Following the addition of phenylmethylsulfonyl fluoride, a serine protease inhibitor, to serum, the serum stability for ProGRP was similar to that in plasma. ProGRP is significantly more stable in plasma than in serum. We speculate that thrombin in serum is one of the factors that inactivate ProGRP in serum by proteolysis of the ProGRP antigen. CONCLUSION: The use of plasma samples for ProGRP may improve the clinical reliability of this marker by minimizing preanalytical changes in ProGRP concentrations.
