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At least 217 records · Page 12Linked to original sources
PubMed1991

Polymorphisms of serum proteins in Japanese patients with vascular diseases. I. Factor XIIIB, plasminogen and complement types in primary varicose veins.

The polymorphisms of the B subunit of coagulation factor XIII (F13B), plasminogen (PLG), complement C6, C7, factor B (BF) and factor I (IF) were studied among 21 unrelated Japanese patients with primary varicose veins (PVV) by isoelectric focusing followed by immunoblotting. The allele frequencies for F13B*2 and IF*A in PVV patients were significantly higher (F13B*2, p = 0.0047; IF*A, p = 0.0006) than those in healthy controls (n = 60). Significant associations of F13B 2 allotype [p = 0.0220, relative risk (RR) = 13.9] and IF A allotype (p = 0.0006, RR = 10.0) with PVV were observed; however, no significant association of PLG, C6, C7 or BF allotype with the disease was found.

Adult↗
PubMed1988

C7 deficiency and persistent haematuria.

A 14-year-old boy had persistent haematuria along with complete C7 deficiency. No significant changes in glomeruli and tubules were found in a renal biopsy specimen by light microscopy and immunofluorescence gave negative results for immune deposits. Electron microscopic examination demonstrated an attenuation of the glomerular capillary basement membrane without lamination and a diagnosis of thin basement membrane disease was made. It would be difficult to conclude that patients with C7 deficiency were predisposed to develop glomerulonephritis caused by immunologic aberrations. A family study failed to provide evidence of an association of C7 deficiency and thin basement membrane disease.

Adolescent↗
PubMed1990

C7 reference typing and nomenclature recommendations.

The results of reference typing for C7 are presented and discussed. It appears that the present literature is using consistent nomenclature except that it was not possible to distinguish between the European C7-3 allele and Japanese C7-6. Oriental populations have both a higher frequency of variants and a greater variety of variants than Caucasian populations. Some samples with complex patterns defied classification, and it is speculated that these may be from persons with duplicated C7 genes. It is recommended that no change to the present system of nomenclature be made before a more detailed molecular understanding of the system is achieved.

Complement C7↗
PubMed1996

Increased levels of soluble complement receptor 1 in serum patients with liver diseases.

Complement receptor type 1 (CR1) is an integral membrane protein of many hematopoietic cells and is found in a soluble form in plasma. Preliminary data have indicated that soluble complement receptor 1 (sCR1) levels in serum were increased in patients with cirrhosis. In this study, sCR1 was measured in patients with various liver diseases with a newly established enzyme-linked immunosorbent assay (ELISA). sCR1 level was elevated in chronic active hepatitis C (24 patients, 62.6 +/- 31 ng/ML; 31 normal controls, 31.4 +/- 7.8 ng/mL, P < .001), and in cirrhosis (35 patients, 143.7 +/- 61 ng/mL, P < .001). The levels increased transiently in 3 patients who had amanita phalloides intoxication. In 25 patients with advanced cirrhosis (pretransplantation screening), there were significant inverse correlations between sCR1 and both the prothrombin index (rs = -.60, P < .002) and the aminopyrine breath test (rs = -.51, P < .01). Following liver transplantation, the levels dropped from 166 +/- 70 to 49 +/- 24 ng/mL (P < .0001), and serial measurements in the posttransplantation period showed a correlation with liver dysfunction, regardless of etiology. Since CR1 is not produced by hepatocytes, the most likely explanation for the increased level of sCR1 is reduced is reduced catabolism. Thus, sCR1 may be added to the short list of large glycoproteins that accumulate in liver disease.

Amanita↗
PubMed1989

The molecular architecture of human complement component C6.

The molecular architecture of human complement component C6 was elucidated at several levels of structural organization. The entire primary structure of C6 was determined by sequencing C6 cDNA that was cloned from a human liver lambda gt11 library. The polypeptide chain of C6 contains 913 amino acids. The protein is homologous with the other terminal components of complement, C7-C9. Specifically, C6 has 29% of its residues identical with C7, and 55 of the 56 cysteines found in C7 match those in C6. The C6 polypeptide chain is cross-linked by 32 disulfide bonds, and most of the cysteines are located in short (34-77 amino acids) discrete segments that exhibit homology with a wide variety of other proteins such as thrombospondin, the low density lipoprotein receptor, epidermal growth factor, and complement factors H and I. C6 is a glycoprotein, and it has two oligosaccharide groups attached to asparagines located near the amino and the carboxyl termini of the molecule. The organization of secondary structural elements in C6 was elucidated using circular dichroism spectroscopy and an empirical method based on sequence analysis. C6 has an estimated 12% alpha-helix, but is comparatively richer in beta-sheet (29%) and beta-turns (21%). Most of the predicted alpha-helical structure resides in a portion of the polypeptide chain that is free of cysteine and which shares homology with C9 and perforin. The tertiary structure of the C6 molecule was visualized by transmission electron microscopy; it has a sickle shape with dimensions of 144 x 66 A. The combined results are discussed and comparisons made with the other late acting components of complement and perforin.

Amino Acid Sequence↗
PubMed1978

Combined genetic deficiency of C6 and C7 in man.

By routine screening of sera, a subject was discovered who showed a sub-total deficiency of C6 and C7. No clinical disease was associated with this deficiency which was transmitted through the subject's family as a single genetic characteristic, the C6 deficiency being associated with a silent allele at the structural locus. The propositus was found to have low quantities of an abnormal C6 which was both antigenically deficient and smaller in size than normal C6 (110,000 daltons compared with 140,000 daltons) and small quantities of apparently normal C7. It is concluded that the most likely explanation for this defect is that the subject has a structural mutation in his C6 gene which produces hyopsynthesis not only of C6 but also of the closely linked gene for C7. These findings suggest the possibility that C6 and C7 may function as a single genetic unit and that the primary transcript copied from the genome includes information for both proteins.

Aged↗
PubMedDate not supplied

Double replica electroblotting for the simultaneous phenotyping of C6 and C7, and its application to the examination of bloodstains.

A new reliable and reproducible technique for the simultaneous determination of C6 and C7 types is presented, which employs double replica electroblotting after isoelectric focusing. It permitted clear discrimination of both C6 and C7 components, and the patterns were nearly comparable to those demonstrated separately. The population data obtained by this new technique fitted the genetic hypothesis. The present double replica electroblotting method was successfully applied to the combined phenotyping of C6 and C7 from bloodstains which were stored at room temperature for up to 4 weeks. The method is quite suitable for medicolegal examination of bloodstains particularly for the saving in the amount of sample.

Blood Stains↗
PubMed1977

The SC5b-7 complex: formation, isolation, properties, and subunit composition.

Activation of C in C8-depleted serum results in the formation of a soluble complex containing C5, C6, and C7. The complex has an electrophoretic mobility of an alpha-globulin, an s-rate of 18.5S, and a m.w. of 668,000 daltons. This complex was isolated and upon SDS polyacrylamide gel electrophoresis it was found to contain, in addition to C5b, C6 and C7, an 88,000 dalton glycoprotein. The protein was identified as the band V protein of the soluble C5b-9 complex. It is referred to as SIIIs-protein, or S-protein. Since the S-protein does not bind to C5b-6, it is concluded that it is incorporated during the fusion of C5b-6 with C7. The SC5b-7 complex exhibits the same neoantigen as the SC5b-9 complex, but compared to the C5b-6 complex it appears to contain an additionally qualitatively distinct neoantigen.

Animals↗
PubMed1994

Complement deficiency predisposes for meningitis due to nongroupable meningococci and Neisseria-related bacteria.

Nongroupable meningococci or bacteria related to the genus Neisseria rarely cause meningitis. Complement deficiency has been identified as a major predisposing factor for meningococcal disease. To assess whether patients with meningitis due to such strains have a complement deficiency, we studied 12 persons. Six patients had meningitis due to nongroupable strains of meningococci, and six patients had meningitis due to Moraxella species or Acinetobacter species. Inherited complement component C7 or C8 deficiency was found in two persons who had had meningitis due to nongroupable meningococci, and one C8-deficient person had had meningitis caused by Moraxella osloensis. Hypocomplementemia resulting from CSF drain-associated shunt nephritis was found in one person with meningitis due to Moraxella nonliquefaciens and in one person with meningitis due to Acinetobacter lwoffi. This rather high frequency of inherited or acquired complement deficiencies among patients with meningitis due to nongroupable meningococci, Moraxella species, and Acinetobacter species justifies the recommendation that such patients must be studied for complement deficiency.

Acinetobacter Infections↗
PubMed1975

A study of complement components C3, C5, C6, C7, C8 and C9 in chronic membranoproliferative glomerulonephritis, systemic lupus erythematosus, poststreptococcal nephritis, idiopathic nephrotic syndrome and anaphylactoid purpura.

In a comparative study the hemolytic activity of C3, C5, C6, C7, C8, C9 and the C3 proactivator (C3PA) were measured in sera of 22 patients with chronic membrano-proliferative glomerulonephritis (CMPGN), 15 patients with idiopathic nephrotic syndrome, 10 patients with systemic lupus erythematosus, 7 patients with anaphylactoid purpura and 10 patients with acute poststreptococcal nephritis. In CMPGN, C3, C5, C6, C7 and C8 were low in the majority of the patients, whereas C9 and C3PA were depressed only in 21% and 11% of the patients, respectively. By contrast, C3PA and C8 showed striking depressions in the idiopathic nephrotic syndrome. In lupus erythematosus, all the C factors, including C3PA were found to be low with the exception of C9, which was normal in 80% of the patients studied. C3, C5, C6 and C7 were found to be depressed in acute glomerulonephritis; C8 and C9 titers were normal. In all patients studied with anaphylactoid purpura, CH50 and C3 titers were elevated markedly.

Adolescent↗
PubMed1996

Molecular bases of combined subtotal deficiencies of C6 and C7: their effects in combination with other C6 and C7 deficiencies.

Combined subtotal deficiency of C6 and C7, in which both proteins are expressed at very low levels, has been observed in homozygous form in two families. A defect at the 5' splice donor site of intron 15 of the C6 gene explains the low molecular weight of the C6 protein and is probably responsible for its low expressed concentration. The C7 defect is more enigmatic: the protein is of normal molecular weight, low circulating concentration, and altered isoelectric point. An Arg > Ser codon substitution in exon 11 is the only molecular alteration within the mature C7 protein. These defects are associated with a characteristic set of polymorphic DNA markers in the C6/C7 region, forming a distinct haplotype. The haplotype has been found in combination with a number of other haplotypes containing defective genes that lead either to C6 or C7 deficiency, but with different consequences. Where it is combined with a C6-deficient gene, the serum C7 levels can be surprisingly high, possibly because there is no C6 generating C56 to consume the C7. In contrast, where the C7 genes are both defective (but still partially functional), there may be a profound deficit of circulating C7 because there is ample C6 to produce C56 and consume the already small amount of C7. Each molecular defect has also been found in isolation and has the expected effect.

Amino Acid Sequence↗
PubMed1989

Recurrent pyogenic meningitis--a retrospective study.

Records of 17 patients who had two or more attacks of pyogenic meningitis were collected from eight centres in the United Kingdom for retrospective analysis. Thirteen patients had intracranial abnormality; of seven with head injury five produced cerebrospinal fluid rhinorrhoea. The first of the 28 attacks seen in these occurred between a few weeks and 12 years of the head injury. Pneumococci were identified in 25 episodes in cerebrospinal fluid. Of six patients without a history of head injury, one had 'spontaneous cerebrospinal fluid rhinorrhoea' and five had pathological changes of the ear. Various organisms were found in the cerebrospinal fluid during the 12 attacks in these five. Four of the 17 patients had primary complement deficiency (C7, C5, C4 and C3b inhibitor); 10 (possibly 11) of 16 attacks in these cases were due to Neisseria meningitidis. Routine radiological investigations including computerized tomography did not always identify the abnormality; radioactive cisternography can help to establish cerebrospinal fluid leak. All 58 episodes of pyogenic meningitis in these 17 patients with different underlying disease responded to conventional treatment with antibiotics without mortality and without undue morbidity. Surgical procedures in intracranial disease had variable success. Correction of complement deficiency is not practical at present. In some patients prophylaxis with antimicrobial drugs is the only method of preventing future attacks.

Adolescent↗
PubMed1992

Distribution of ORM1, C6, C7 and APO C-II allele frequencies in populations from mainland Italy and Sardinia.

The genetic variation of the human plasma proteins ORM1, C6, C7 and APO C-II was investigated by isoelectric focusing followed by immunoblotting in populations from mainland Italy and Sardinia. The frequencies of ORM1*1 were 0.621 and 0.564, while those of C6*A were 0.657 and 0.706 on mainland Italy and in Sardinia, respectively. In the Roman sample, 8 heterozygotes with C6 variant alleles were encountered, while none were observed in Sardinians. For C7 and APO C-II a number of heterozygotes with the rare alleles C7*2 and APO C-II*2 were found, but their frequency did not reach polymorphic levels in either population. The two populations showed a significant difference in the gene frequencies distribution for ORM1.

Alleles↗
PubMed1997

Molecular bases of C7 deficiency: three different defects.

The molecular basis of C7 deficiency has been investigated in two Irish families and a number of Israeli families of Moroccan Sephardic Jewish origin. Exon PCR and sequencing revealed a heterozygous point mutation at the 3' splice acceptor site of intron 1 in one Irish family. In the other Irish family, exons 7 and 8 failed to amplify and they were shown to be deleted. Marker haplotype studies of the C6 and C7 gene region and Southern blots show that the Irish family with the splice defect also segregate for the deletion, which is not easily detected in heterozygotes. The Israeli C7-deficient cases all share a C7 haplotype and are homozygous for a mis-sense mutation in exon 9. However, one individual is heterozygous for markers at adjacent C6 loci, showing that there has been an intergenic recombination and suggesting that the deficiency mutation is of appreciable antiquity.

Amino Acid Sequence↗
PubMed1982

Transmembrane channel formation by complement: functional analysis of the number of C5b6, C7, C8, and C9 molecules required for a single channel.

Earlier studies have shown that sequential treatment of resealed erythrocyte ghosts with C5b6, C7, C8, and C9 leads to insertion of hydrophobic peptides from these complement proteins into the membrane and assembly of transmembrane channels. The number of molecules of each of the proteins required for assembly of the membrane-associated channel structure was evaluated by measuring the quantitative relationship between the doses of the individual proteins and the release of two trapped markers, sucrose and inulin, from ghosts after channel formation. The incubation period was sufficient to attain equilibrium of marker distribution between the ghosts and the extracellular fluid. Two markers of different size (sucrose and inulin, 0.9 and 3 nm molecular diameter, respectively) were used in order to develop information on the molecular composition of small and large channels, respectively. We found that participation of C5b6, C7, and C8 in channel formation displayed one-hit characteristics, regardless of marker size. By contrast, the participation of C9 was one-hit with respect to the sucrose marker, whereas with respect to the inulin marker the C9 reaction was multi-hit. Our results are compatible with the view that these markers are released through a channel structure in the membrane that is a monomer of C5b--9 of the composition C5b61 C71C81C9n, in which n = 1 for channels permitting passage of sucrose and n = 2 for channels allowing transit of inulin.

Animals↗
PubMed1998

Galanin receptor-mediated inhibition of glutamate release in the arcuate nucleus of the hypothalamus.

It is thought that galanin, a 29 amino acid neuropeptide, is involved in various neuronal functions, including the regulation of food intake and hormone release. Consistent with this idea, galanin receptors have been demonstrated throughout the brain, with high levels being observed in the hypothalamus. However, little is known about the mechanisms by which galanin elicits its actions in the brain. Therefore, we studied the effects of galanin and its analogs on synaptic transmission using an in vitro slice preparation of rat hypothalamus. In arcuate nucleus neurons, application of galanin resulted in an inhibition of evoked glutamatergic EPSCs and a decrease in paired-pulse depression, indicating a presynaptic action. The fragments galanin 1-16 and 1-15 produced a robust depression of synaptic transmission, whereas the fragment 3-29 produced a lesser degree of depression. The chimeric peptides C7, M15, M32, and M40, which have been reported to antagonize some actions of galanin, all produced varying degrees of depression of evoked EPSCs. In a minority of cases, C7, M15, and M40 antagonized the actions of galanin. Analysis of mEPSCs in the presence of TTX and Cd2+, or after application of alpha-latrotoxin, indicated a site of action for galanin downstream of Ca2+ entry. Thus, our data suggest that galanin acts via several subtypes of presynaptic receptors to depress synaptic transmission in the rat arcuate nucleus.

Animals↗