Measurement of complement hemolytic activity, generation of complement-depleted sera, and production of hemolytic intermediates.
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Animals↗
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Hepatitis C-associated complement cold activation.
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Adolescent↗
Functional role of the fast transient outward K+ current IA in pyramidal neurons in (rat) primary visual cortex.
A molecular genetic approach was exploited to directly test the hypothesis that voltage-gated K+ (Kv) channel pore-forming (alpha) subunits of the Kv4 subfamily encode the fast transient outward K+ current (IA) in cortical pyramidal neurons and to explore the functional role of IA in shaping action potential waveforms and in controlling repetitive firing in these cells. Using the biolistic gene gun, cDNAs encoding a mutant Kv4.2 alpha subunit (Kv4.2W362F), which functions as a dominant negative (Kv4.2DN), and enhanced green fluorescent protein (EGFP) were introduced in vitro into neurons isolated from postnatal rat primary visual cortex. Whole-cell voltage-clamp recordings obtained from EGFP-positive pyramidal neurons revealed that IA is selectively eliminated in cells expressing Kv4.2DN. The densities and properties of the other Kv currents are unaffected. In neurons expressing Kv4.2DN, input resistances are increased and the (current) thresholds for action potential generation are decreased. In addition, action potential durations are prolonged, the amplitudes of afterhyperpolarizations are reduced, and the responses to prolonged depolarizing inputs are altered markedly in cells expressing Kv 4.2DN. At low stimulus intensities, firing rates are increased in Kv4.2DN-expressing cells, whereas at high stimulus intensities, Kv4.2DN-expressing cells adapt strongly. Together, these results demonstrate that Kv4alpha subunits encode IA channels and that IA plays a pivotal role in shaping the waveforms of individual action potentials and in controlling repetitive firing in visual cortical pyramidal neurons.
Action Potentials↗
[Serological investigation of influenza type A and B in university students, Brazil].
Wide serological prevalence of influenza A and B was verified by the serological survey covering 200 students of the University of S. Paulo during the 1984-1985 period. The humoral antibodies were detected by the single radial haemolysis technique, whose arithmetic titres averages were greater for both subtypes, (H1N1) and (H3N2) of the influenza A virus strains recently isolated from the population. However, the situation of this type B virus was not the same as that of type A seeing that the B/Engl/847/73, although an older strain, showed better reactogenicity than the other strains evaluated. It is possible that is was responsible for the primo infection of most of the components of the group surveyed, as the phenomenon of the "Original Antigenic Sin" explains. The antibody responses to subtypes of influenza A and B in this survey demonstrated levels with low SRH titres (2.5 to 3.5 mm) and high SRH titres (> or = 4.0 mm) related to the lowest and highest levels of suggest protection against infection. Individual immunity and persistence of antibody are related to frequency and recent occurrence of exposition to influenza. As concerns the formulation of influenza vaccine it was established that this preserves the antigen selection of the new strains isolated from the population, mainly due to the behavior of the influenza A virus.
Adult↗
Entamoeba histolytica: antigenic characterization of axenic strains from Brazil.
Trophozoites from cultures of Entamoeba histolytica strains isolated and grown axenically in Brazil (ICB-CSP, ICB-462 and ICB-32) were used for immune sera production and for characterization of their antigens by using electrophoretic and glycoproteic profiles, in parallel with a standard strain isolated and kept under axenic conditions in USA (HK-9). Hyperimmune sera, presenting high antibody titers with homologous and heterologous antigens, were obtained. The four strains in study revealed similar and complex electrophoretic and glycoproteic profiles showing polypeptides with molecular weights ranging from 200 to less than 29 kDa. No significant differences were detected between the pathogenic and non-pathogenic strains.
Animals↗
Trypanosoma cruzi: course of infection in platelets-depleted mice.
The effect of platelet depletion on the course of Trypanosoma cruzi infection in BALB/c mice was investigated. Thrombocytopenia was achieved by inoculation of rabbit anti-platelet IgG during the parasitemic phase of the infection. The number of parasites in the blood of anti-platelet IgG treated was significantly higher than that of non-treated control mice, during the phase of high parasitemia. Cumulative mortality of platelet-depleted mice was consistently but not significantly higher than that of control mice up to the 32nd day of infection; from the 33rd day on they were equivalent, no mortalities occurring from then on, until observations were discontinued on the 60th day. These results suggest that platelets participate of the mechanisms of parasites removal from the bloodstream, but do not have an effective role in the mechanisms of defence against T. cruzi, during the acute phase of infection.
Animals↗
Prostaglandin E1 reduces the glomerular mRNA expression of monocyte-chemoattractant protein 1 in anti-thymocyte antibody-induced glomerular injury.
To study whether prostaglandins (PG) can regulate the mRNA expression of monocyte-chemoattractant protein 1 (MCP-1) in glomerular immune injury, MCP-1 mRNA levels were evaluated in anti-thymocyte antibody (ATS) -induced glomerular injury by Northern blotting and reverse transcription-polymerase chain reaction. Immune injury was induced in vivo by the intravenous application of ATS to male Wistar rats and in vitro by the perfusion of isolated rat kidneys with ATS and rat serum. In vivo 3 h and 5 days after antibody application, glomerular mRNA expression of MCP-1 was markedly enhanced compared with controls. In the isolated perfused kidney, antibody and complement also induced an increase in MCP-1 expression at 10 min and 60 min after antibody perfusion. When the rats were treated with PGE (250 micrograms, twice daily), the increase in MCP-1 expression was reduced. This was associated with a reduction of intraglomerular recruitment of monocytes/macrophages. In the isolated perfused kidneys, PGE1 (1 mg/L) prevented the antibody- and rat serum-stimulated increase in glomerular MCP-1 mRNA expression. These data demonstrate that PGE1 reduces glomerular MCP-1 mRNA expression in glomerulonephritis and in the isolated perfused rat kidney after induction of immune injury with antibody and complement. The data suggest that prostaglandins might mediate MCP-1 effects in glomerular immune injuries.
Alprostadil↗
Total hemolytic complement (CH50) and its fractions (C3 and C4) in the sera of diabetic patients with periodontitis.
The total hemolytic complement activity (CH50) and its fractions C3 and C4 were determined in 50 patients with Type II or non-insulin dependent diabetes mellitus (NIDDM) and 50 nondiabetic patients with periodontitis. The values were compared with those of 50 age and sex matched controls. An elevation of CH50 was observed in both the diabetic and nondiabetic patients, compared to controls. The diabetic patients with periodontitis showed a significantly higher complement activity compared to nondiabetic patients with periodontitis. The C3 and C4 values were significantly elevated in both diabetic and nondiabetic patients when compared with the control group. The elevation being more pronounced in diabetic groups.
Adult↗
A familial case of hereditary angioneurotic edema in Japan.
A 53-year-old man was admitted with impairment of breathing following laryngeal edema. Serum levels of CH50 (22 U/ml), C4 (3 mg/dl), C1-INH protein (10.6 mg/dl) and C1-INH activity (LT 25%) were low. Complement study of the patient's family members revealed that he was one of 5 patients in 3 generations with hereditary angioneurotic edema (HANE). Administration of the androgen derivatives Danazol (600 mg/day) and Oxymetholone (30 mg/day) effectively increased serum levels of C1-INH activity and C4. Though eruption and hepatic dysfunction attributable to administration of the drugs appeared, these side effects improved after withdrawal of the drugs. Subsequently, the treatment with Danazol at a low dose (100 mg/day) was resumed, and the patient has had no episodes of edema for the past 3 years. Regarding the familial cases of HANE, fewer than 20 have been reported in Japan.
Angioedema↗
Allergic granulomatous angiitis and peripheral nerve lesion.
We examined 8 cases of allergic granulomatous angiitis (AGA). All cases showed peripheral nerve lesion, comprising damage of all myelinated fibers, which was more severe in larger ones. Immunofluorescent deposits of IgE were detected in the peripheral myelin. There was lymphocyte infiltration both around the endoneural capillaries and in the endoneurium, and an increase of endothelial cells. Nerve ischemia due to obstruction of the vasa nervorum, circulation insufficiency of the small vessels, or immunological abnormality through IgE may play a pathogenetic role in the peripheral neuropathy of AGA.
Child↗
Four-site intradermal postexposure boosters in previously rabies vaccinated subjects.
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Complement Hemolytic Activity Assay↗
Clinical features of patients with mild systemic lupus erythematosus.
Clinical features of 16 patients with mild systemic lupus erythematosus (SLE) were compared with those of 21 control patients with moderate or severe disease. Age at the time of diagnosis of SLE was higher in mild disease group. The incidence of the coexistence of Sjögren's syndrome (SS) at the time of diagnosis of SLE was higher in patients who later developed mild disease. Anti-Sm antibody and decreased levels of C3, C4, and CH50 occurred less frequently in patients with mild disease. SLE patients with the coexistence of SS at the time of diagnosis of SLE may represent a subset with a benign prognosis.
Adolescent↗
Levamisole as an immunopotentiator for T cell deficiency.
Levamisole, a widely used antihelminthic drug has been shown to restore cutaneous delayed hypersensitivity in anergic patients with cancer and to amplify the activation of T lymphocytes by in vitro mitogens. Levamisole has been approved for the treatment of colon cancer in combination with 5 Fluorouracil. Herein we report a case of a 5 1/2 y.o. male who presented with a fulminant, disseminated mycobacterial infection of his joints secondary to a deficiency in his cellular mediated immunity in association with chemotherapy for a T cell leukemia. The patient was treated with Levamisole resulting in restoration of his T cell functions and resolution of his mycobacterial infection.
Arthritis, Infectious↗
Whole complement hemolytic activity (CH50) following infusion of stroma-free and polyhemoglobin solutions in rats.
We developed a method to determine whole complement hemolytic activity (CH50) in rat plasma using a modification of the method of Mayer(1). Plasma CH50 level in 30 male Sprague Dawley rats was 1000 +/- 200 units. Following infusions with human and rat stroma-free hemoglobin or polyhemoglobin solutions, CH50 did not change significantly in rats when compared to albumin infused rats. On the other hand, CH50 significantly decreased in the group receiving membrane stroma and bacterial endotoxins.
Animals↗
Isolation, characterization, and cloning of porcine complement component C7.
Activation of the complement system through the classical, alternative, or lectin pathway results in the formation of the terminal complement complex. C7 plays an integral role in the assembly of this complex with target cell membranes. To date, only human C7 has been cloned and characterized; thus, in this study, we characterized the porcine complement component C7. Porcine C7 was isolated by affinity chromatography as a single glycoprotein with an approximate molecular mass of 90 kDa and 100 kDa under reducing and nonreducing conditions, respectively. The full-length porcine C7 cDNA was isolated, and the predicted amino acid sequence exhibited 80% identity with human C7 with conservation of the cysteine backbone and two putative N-linked glycosylation sites. Porcine C7 mRNA expression was detected in all tissues investigated, except polymorphonuclear and mononuclear leukocytes. Addition of purified porcine C7 restored the hemolytic activity of C7-depleted human sera in a dose-dependent manner. A functionally inhibitory mAb against porcine C7 attenuated the hemolytic activity of human, rabbit, or rat sera, suggesting an important conserved C7 epitope among species. These data demonstrate that porcine and human C7 are highly conserved, sharing structural and functional characteristics.
Amino Acid Sequence↗
Diversity in intrinsic strengths of the human complement system: serum C4 protein concentrations correlate with C4 gene size and polygenic variations, hemolytic activities, and body mass index.
Among the genes and proteins of the human immune system, complement component C4 is extraordinary in its frequent germline variation in the size and number of genes. Definitive genotypic and phenotypic analyses were performed on a central European population to determine the C4 polygenic and gene size variations and their relationships with serum C4A and C4B protein concentrations and hemolytic activities. In a study population of 128 healthy subjects, the number of C4 genes present in a diploid genome varied between two to five, and 77.4% of the C4 genes belonged to the long form that contains the endogenous retrovirus HERV-K(C4). Intriguingly, higher C4 serum protein levels and higher C4 hemolytic activities were often detected in subjects with short C4 genes than those with long genes only, suggesting a negative epistatic effect of HERV-K(C4) on the expression of C4 proteins. Also, the body mass index appeared to affect the C4 serum levels, particularly in the individuals with medium or high C4 gene dosages, a phenomenon that was dissimilar in several aspects from the established correlation between body mass index and serum C3. As expected, there were strong, positive correlations between total C4 gene dosage and serum C4 protein concentrations, and between serum C4 protein concentrations and C4 hemolytic activities. There were also good correlations between the number of long genes with serum levels of C4A, and the number of short genes with serum levels of C4B. Thus, the polygenic and gene size variations of C4A and C4B contribute to the quantitative traits of C4 with a wide range of serum protein levels and hemolytic activities, and consequently the power of the innate defense system.
Adult↗
Regulator of complement activation (RCA) locus in chicken: identification of chicken RCA gene cluster and functional RCA proteins.
A 150-kb DNA fragment, which contains the gene of the chicken complement regulatory protein CREM (formerly named Cremp), was isolated from a microchromosome by screening bacterial artificial chromosome library. Within 100 kb of the cloned region, three complete genes encoding short consensus repeats (SCRs, motifs with tandemly arranged 60 aa) were identified by exon-trap method and 3'- or 5'-RACE. A chicken orthologue of the human gene 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 2, which exists in close proximity to the regulator of complement activation genes in humans and mice, was located near this chicken SCR gene cluster. Moreover, additional genes encoding SCR proteins appeared to be present in this region. Three distinct transcripts were detected in RNA samples from a variety of chicken organs and cell lines. Two novel genes named complement regulatory secretory protein of chicken (CRES) and complement regulatory GPI-anchored protein of chicken (CREG) besides CREM were identified by cloning corresponding cDNA. Based on the predicted primary structures and properties of the expressed molecules, CRES is a secretory protein, whereas CREG is a GPI-anchored membrane protein. CREG and CREM were protected host cells from chicken complement-mediated cytolysis. Likewise, a membrane-bound form of CRES, which was artificially generated, also protected host cells from chicken complement. Taken together, the chicken possesses an regulator of complement activation locus similar to those of the mammals, and the gene products function as complement regulators.
Amino Acid Sequence↗
Semisynthetic hygromycin A analogs: synthesis and anti-bacterial activity of derivatives lacking the furanose moiety.
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Animals↗