The effect of systemic decomplementation with cobra venom factor on corneal complement levels in guinea pigs.
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The authors examined the effect of systemic administration of cobra venom factor (CVF) on hemolytic complement levels in guinea pig sera and corneas. Guinea pigs received repeated intraperitoneal injections of CVF. Sera and corneas were obtained before and 1, 2, 5, 8, 10, 12, 16, and 20 d after the initial injection of CVF. Total hemolytic complement activity was measured by lysis of sheep erythrocytes sensitized with rabbit antibodies. There was a significant decrease in serum complement levels at days 1, 2, 5, 8, and 10 after the initial injection of CVF. After this, complement levels rose to levels that exceeded preinjection values. Complement levels in corneas also declined after CVF injections with a significant decrease at days 2, 5, 8, and 10 and a return to normal thereafter. Corneal complement depletion and restoration lagged behind serum. Moreover, the rate of complement depletion and restoration was greater for serum than cornea. Light microscopic examination of representative corneas at each time did not show local tissue changes during decomplementation. This is first study (to the authors' knowledge) to document corneal complement depletion by systemic administration of CVF. Low-to-absent corneal complement levels were present 2 d after the initial injection of CVF and persisted for 6 d. This model could be used to study the influence of complement on traumatic and immunologic injuries to the cornea. (+info)
A familial case of hereditary angioneurotic edema in Japan.
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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. (+info)
Functional role of the fast transient outward K+ current IA in pyramidal neurons in (rat) primary visual cortex.
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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. (+info)
Toxin(s), other than cholera toxin, produced by environmental non O1 non O139 Vibrio cholerae.
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A total of 39 Vibrio cholerae non O1 non O139 strains were isolated from surface waters of different parts of Dhaka City, Bangladesh. All these strains showed lack of ctx or zot gene, as demonstrated by the PCR analysis. Eighteen representative strains were tested for enterotoxin production using a rabbit ileal loop model, of which live cells of 8 strains and culture filtrates of 6 strains produced fluid accumulation in ileal loops. However, none of them produced heat stable toxin (ST), as detected by suckling mouse assay. On the other hand, 15% of isolates produced cytotoxin as detected by the Chinese Hamster Ovary (CHO) cell assay. Fifty times concentrated culture filtrates of the representative strains did not give any precipitin band against the anti-cholera toxin, suggesting the strains produced an enterotoxin, which is antigenically different from known cholera toxin (CT). Eighty percent of the total isolates were found to be positive for heat labile haemolysin detected by tube method, whereas, 39% were found positive by the Christie-Atkins-Munch-Petersen (CAMP) method. However, 87% of the isolates were positive for haemagglutinin/protease and all of the strains were positive for mannose-sensitive-haemagglutinin assay. (+info)
Immunoglobulins and complement factor C4 in adult rhinosinusitis.
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We assessed whether complement and its factor C4 or abnormal immunoglobulin levels are associated with chronic or recurrent rhinosinusitis. We used multiple patient and control groups to obtain clinically meaningful data. Adult chronic or recurrent rhinosinusitis and acute purulent rhinosinusitis patients were compared with unselected adults and controls without previous rhinosinusitis. Associated clinical factors were reviewed. Levels of immunoglobulins, plasma C3, C4 and classical pathway haemolytic activity were analysed. C4 immunophenotyping was used to detect C4A and C4B deficiencies as null alleles. Complement was up-regulated in rhinosinusitis. C4A nulls and low IgA, IgG, IgG1, IgG2, IgG3 and IgG4 levels were all more common in chronic or recurrent rhinosinusitis patients than in unselected and healthy controls. We searched for relevant differences between the patient groups. According to stepwise logistic regression analysis, nasal polyposis [odds ratio (OR) 10.64, 95% confidence interval (CI) 2.5-45.7, P = 0.001], bronchial asthma (OR 8.87, 95% CI 2.3-34.9, P = 0.002), C4A null alleles (OR 5.84, 95% CI 1.4-24.9, P = 0.017) and low levels of IgG4 together with either IgG1 or IgG2 (OR 15.25, 95% CI 1.4-166.8, P = 0.026) were more common in chronic or recurrent rhinosinusitis than in acute rhinosinusitis patients. Isolated low IgG subclasses had limited value in patient assessment. C4A null alleles are associated with chronic or recurrent rhinosinusitis, potentially through their effect on immune defence and inflammation control. Multiple clinical and immunological parameters may need to be evaluated when searching for prognostic variables. (+info)
Use of serum or buffer-changed EDTA-plasma in a rapid, inexpensive, and easy-to-perform hemolytic complement assay for differential diagnosis of systemic lupus erythematosus and monitoring of patients with the disease.
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We previously described a simplified quantitative hemolytic assay for classical pathway (CP) hemolytic function in serum that has been shown to correlate with the 50% hemolytic complement (CH50) assay. In the present study, we used this assay to compare CP functions; plasma levels of C3, C4, and C3dg; and ratios of C3dg to C3 in healthy individuals and patients with systemic lupus erythematosus (SLE) or rheumatoid arthritis (RA) with different degrees of complement activation. A significant depression in CP function and levels of C4 and C3 and increased C3dg levels and C3dg/C3 ratios were observed in the SLE patients. In patients with RA, CP function was normal, whereas C3, C4, and C3dg levels and the C3dg/C3 ratio were elevated. The SLE results are compatible with systemic complement consumption, whereas the RA data suggest an acute-phase reaction with a normal C3 catabolic rate. To facilitate the handling of patient samples, we also developed a method to restore the hemolytic function of EDTA-plasma by transferring it to Veronal-buffered saline containing the thrombin inhibitor lepirudin. This process inhibits coagulation and enables complement activation, allowing a longer time lag between sample harvesting and testing. These results, combined with previous correlation studies, suggest that the CP hemolytic assay can effectively replace the CH50 assay for routine SLE differential diagnosis and monitoring of disease activity. (+info)
The effects of complement depletion on corneal inflammation in rats.
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There are indications that complement activation may be involved in inflammatory processes of the cornea. To investigate the role of the complement system in experimental keratitis, rats were depleted of their plasma complement by treatment with cobra venom factor (CVF). intraperitoneal injection of CVF resulted in undetectable complement serum activity for 6 days when measured by a hemolytic assay. The corneal inflammatory response, induced by a single intracorneal injection of heterologous serum into nonsensitized CVF-treated rats, was suppressed significantly. The onset of the clinical symptoms of keratitis was delayed, and the severity was reduced. In addition, analysis of the serum antibody titers showed impaired antibody synthesis in the CVF-treated group. When keratitis was induced by an intracorneal antigen challenge in sensitized rats, no difference was observed when comparing the clinical signs of keratitis of CVF-treated animals with sham-treated animals. In addition, CVF treatment did not alter the course of lipopolysaccharide (LPS)-induced corneal inflammation. These findings suggest that the role of plasma complement activation in antigen- and LPS-induced keratitis appears to be limited. The implications for the immunopathologic mechanisms underlying keratitis are discussed. (+info)
Serum complement 3 (C3) and complement 4 (C4) level in febrile neutropenia patients at Dr. Kariadi Hospital, Semarang and Dr. Moewardi Hospital, Surakarta.
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AIM: to identify the serum complement 3 (C3) and complement 4 (C4) level in febrile neutropenia and non-febrile neutropenia patients. METHODS: this is a cross-sectional prospective study. Samples were collected from patients with febrile neutropenia as sample group and patients with neutropenia but without fever as control. Both groups were tested for serum complement 3 and complement 4 level, and the data were analyzed using student T-test. RESULTS: from 37 neutropenia patients, 23 were classified as febrile neutropenia group and 14 in non-febrile neutropenia as control group. Total mean neutrophil count was 653.22/ml serum in sample group and 594.36/ml serum in control group (p=0.575). Mean C3 level was 95.74 ug/dl in sample group and 130.00 ug/dl in control group, showing significant difference with p=0.031. The mean serum C4 level was 34.13 ug/ml in sample group and 34.00 ug/dl in control group, the difference is not significant with p=0.98. When sample C3 and C4 data were combined, the total level was 125.61 ug/ml, which was significantly lower than the total C3 and C4 in control group 184.07 ug/dl. (p=0.04). CONCLUSION: in febrile neutropenia there is significant decrease of serum C3 level compared to non-febrile neutropenia. Serum C4 level in febrile neutropenia group is lower than the non-febrile neutropenia group, but the difference is not significant. (+info)