ASSOCIATION OF THE C2-DEFICIENCY GENE (C2*QO) WITH THE C4A*4, C4B*2 GENES

C4 typing in thirteen homozygous C2-deficient patients and in a family with heterozygous C2 deficiency showed a strong association of the C2-deficiency gene (C2*QO) with the relatively rare C4A* C4B*2 haplotype.     

Aqueous polymerization of acrylic acid initiated by KMnO4 — H2C2O4 redox system

Polymerization of acrylic acid in aqueous solution initiated by permanganate-oxalic acid redox pair has been studied at 32 ± 0.2°C in nitrogen atmosphere. The rate of polymerization has been found to be nearly independent of oxalic acid concentration within the range 1.87 to 9.33 · 10^?3 mole/l. and decreases only at higher concentrations of the oxalic acid. The rate has also been found to vary with the first power of the monomer concentration (within the range 1.44 to 5.76 · 10^?2 mole/l.) and the first power of the catalyst concentration (8.0 to 28.0 · 10^?5 Mole/l.). It is, however, proportional to half power at relatively high catalyst concentration, at fixed concentrations of oxalic acid (1.03 · 10^?2 mole/l.) and the monomer (5.76 · 10^?2 mole/l.). At higher concentration of monomer the catalyst exponent has been found to be nearly unity for both the higher and lower concentrations of the catalyst. The initial rate of polymerization increases with increase in temperature. The overall energy of activation has been found to be 19.56 kcal/mole within the temperature range 30 – 45°C. Organic solvents and salts (KCI, Na₂SO₄, and Na₂C₂O₄) depress the rate but MnSO₄ 4H₂O has been found to increase the initial rate but depress the maximum conversion.     

The phylogeny and evolution of the thioester bond-containing proteins C3, C4 and α2–macroglobulin

Summary: The complement system is an effector of both the acquired and innate immune systems of the higher vertebrates. It has been traced back at least as far as the echinoderms and so predates the appearance of the antibodies, T-cell receptors and MHC molecules of adaptive immunity. Central to the function of complement is the reaction of the thioester bond located within the structure of complement components C3 and C4, The structural thioester first appeared in a protease inhibitor, α₂-macroglobulin, in which it is involved in the immobilisation and entrapment of proteases. An important development in the C3 molecule has been the acquisition of a catalytic His residue which greatly increases the rate of reaction of the thioester with hydroxyl groups and with water.     

C2_4_4 microheterogeneity and HLA Class I

The microheterogeneity of the tetranucleotide repeat locus C2_4_4 situated in the HLA class I region (6p21.3) was investigated by sequencing 50 alleles in an Austrian population sample of 240 unrelated Caucasoid individuals. Several different sequences were found in alleles of the same length. Analysis of the associations between the sequenced C2_4_4 alleles and HLA class I showed a strong linkage disequilibrium between the C2_4_4*9 sequence variants and two different HLA class I haplotypes, as well as between the most common *17 sequence and one HLA-ABC haplotype. No clear cut association could be observed in C2_4_4*16 and *18. The results of this study demonstrate that the exclusive use of microsatellite polymorphisms for the definition of HLA haplotypes is generally not possible.     

Aqueous polymerization of methacrylamide initiated by KMnO4/H2C2O4 redox system

The polymerization of methacrylamide initiated by potassium permanganate/oxalic acid redox system has been studied at 35 ± 0.2°C in a nitrogen atmosphere. The rate of polymerization is independent of the activator (oxalic acid) concentration within the range 5·10^?3 to 10·10^?3 mole·1^?1, except at very high (above 10·10^?3 mole·1^?1) or at very low (below 5·10^?3 mole·1^?1) concentrations of the activator. The rate varies linearly at low monomer concentration (up to 5.87·10^?2 mole·1^?1). The catalyst exponent decreases from nearly unity (0.91) to 0.66 with increase in concentration of the catalyst (KMnO₄) probably due to participation of primary radicals in the termination of the growing chain. The addition of strong acid (H₂SO₄) within the range 5 · 10^?4–15 · 10^?4 mole · l^?1, shows a constant pH of 2.7 resulting in no change in initial rate. With activator alone (H₂C₂O₄ · 2H₂O), within the pH range 2.7 to 2.9 an optimum is observed. The initial rate increases with increase in polymerization temperature. The overall energy of activation as calculated from the ARRHENIUS plot has been found to be 15.1 kcal · mole^?1 within the temperature range 30–50°C. Organic solvents (water miscible only) depress the initial rate and the maximum conversion. Small amounts of neutral salts (KCl and Na₂SO₄), however, show no appreciable effect on the polymerization rate, but small amounts of manganous salts (MnSO₄) can increase the initial rate to a considerable extent. High concentrations of MnSO₄ result in termination of the growing chain. A complexing agent, Na₂F₂, decreases the initial rate but increases the maximum conversion. Introduction of fresh catalyst at intermediate stages of polymerization increases both the rate of the reaction and the conversion.     

Response to pegylated interferon alfa‐2a and ribavirin in chronic hepatitis C genotype 4

The safety and efficacy of pegylated interferon (PEG‐IFN) alfa‐2a and ribavirin were studied among patients treated for genotype 4 chronic hepatitis C. Ninety‐five patients with chronic hepatitis C genotype 4 were treated with PEG‐IFN alfa‐2a (180 µg/week) plus ribavirin (≥11 mg/kg/day) for 48 weeks. The primary end point was sustained virological response, defined as non‐detectable levels of HCV RNA at the end of follow up (week 72). The proportion with sustained virological response was 58/95 = 61.1% (95% CI = 50.5–70.9%). Side effects were generally mild, well managed by dose reductions (in 62% of patients); in only two patients were side effects sufficiently severe to require treatment interruption. Ninety percent of patients adhered to treatment up to week 12, and their sustained virological response rate was higher compared to non‐adherent (65% vs. 22%, respectively, P = 0.012). None of the patients who failed to achieve 1 log reduction of viral load by week 8 (n = 15), or 2 log reduction by week 12 (n = 17), had a sustained virological response. In conclusion, sustained virological response in genotype 4 Egyptian patients treated with PEG‐IFN alfa‐2a and ribavirin was estimated around 60%, intermediate between sustained virological response observed in genotype 1 and genotype 2–3 patients in Western countries. The early virological response (week 4 or week 8) should be investigated as a criterion to decide whether the patient may benefit from a shorter duration of therapy. J. Med. Virol. 81:1576–1583, 2009. © 2009 Wiley‐Liss, Inc.     

Combined Heterozygous Deficiency of the Classical Complement Pathway Proteins C2 and C4

Genetic deficiencies of components of the classical pathway of complement activation are associated with an increased risk for the development of autoimmune and immune complex-mediated diseases. In the present study we report on the molecular and clinical features associated with combined heterozygous C4 and C2 deficiency in 15 individuals investigated within six families. Approximately 30% of the individuals manifested SLE or another autoimmune condition. Heterozygous C2 deficiency was related to a 28-bp deletion in the C2 gene (C2 deficiency type I), in most cases within the HLA-A25 B18 C2Q0 BfS C4A4B2 DR2 haplotype. Among 13 partial C4-deficient haplotypes transmitted, 8 carried C4A*Q0 alleles and 5 C4B*Q0 alleles. In seven cases the C4A*Q0 alleles were associated with a deletion of the C4A/CYP21P genes within the HLA-B8 C2C BfS C4AQ0B1 DR3 haplotype. In three cases, the C4B*Q0 allele was associated with a deletion of the C4B/CYP21P genes within the HLA-B18 C2C BfF1 C4A3BQ0 DR3 haplotype. In the other cases, C4A*Q0 or C4B*Q0 was dependent on as yet uncharacterized defects in the C4 gene or in C4 gene expression. In view of the relatively high frequency of heterozygous C4 deficiency in the normal Caucasian population, the expected frequency of the combined deficiency should approximate 0.001.     

ATF4重组慢病毒抑制C2C12细胞增殖并促凋亡

目的 构建人活性转录因子4(ATF4)慢病毒,探讨C2C12细胞成骨分化过程中ATF4基因慢病毒修饰对其增殖和凋亡的影响.方法 构建ATF4重组慢病毒载体质粒,然后与2个包装质粒共转入293T细胞中包装成ATF4慢病毒(LV-ATF4);用病毒感染C2C12细胞,并用流式细胞仪(FCM)检测BMP2诱导C2C12细胞分化时对其增殖凋亡的影响,免疫印迹法检测凋亡相关蛋白的表达,电子显微镜观察凋亡细胞的形态学结构变化.结果 成功构建和包装了ATF4重组慢病毒.FCM检测结果表明,BMP2+ LV-ATF4处理组S期细胞(14.89％)低于BMP2+ LV-GFP组(30.64％) (P ＜0.05);BMP2+ LV-ATF4处理组细胞凋亡率(31.06％)高于BMP2+ LV-GFP组(11.39％)(P＜0.05);凋亡相关蛋白的表达与FCM结果一致.结论 在BMP2诱导C2C12细胞成骨分化时,LV-ATT4慢病毒可促进C2C12细胞的凋亡,抑制其增殖.     

Depletion of C2 and C4 in Sera from Hamsters Bearing Herpes Simplex Type 2-Induced Tumors

Total hemolytic complement activity (CH₅₀) was compared in sera from normal and tumor-bearing hamsters. CH₅₀ ranged from 160 to 216 in normal animals and from 82 to 152 in tumor-bearing animals. Preliminary screening assays indicated that of 9 complement components assayed, only C2 and C4 showed differences in titer in both normal and tumor-bearer sera. In an expanded study, examination of sera from 12 normal and 14 tumor-bearing hamsters showed that the mean C4 and C2 levels were approximately 88 and 70% below those seen in normal sera, respectively.     

Revised nomenclature for human complement component C4*2

This note describes the recommended designations for allotypes of human complement component C4, which were approved by the Nomenclature Committee of the International Union of Immunological Societies (IUIS).     

Effects of Cocatalysts on Propene Polymerization with [t‐BuNSiMe2(C5Me4)]TiMe2

Propene polymerization was conducted using [t‐BuNSiMe₂(C₅Me₄)]TiMe₂ combined with various cocatalysts at 0°C, and kinetic profiles were investigated under atmospheric pressure of propene in a semibatch system. Dried methylaluminoxane (MAO), which was free of Me₃Al, was found to be more active than the standard MAO system, resulting in a steady polymerization rate and giving higher molecular‐weight polypropenes. Sampling experiments during the polymerization showed an almost linear relationship between the number‐average molecular weight, M̄_n, and polymerization time while retaining a narrow molecular‐weight distribution, whereas the results of batch polymerization with different monomer concentrations and post‐polymerization indicated that chain transfer reactions occurred to a minor degree under these polymerization conditions. Additive effects of trialkylaluminium on the dried MAO system showed that the polymer yield was increased by the addition of i‐Bu₃Al and Oct₃Al and decreased by Me₃Al and Et₃Al. All of the trialkylaluminium compounds increased the number of polymer chains (N), and the Et₃Al system showed the highest N value with the lowest M̄_n value.     

Increase in GFAP‐positive astrocytes in histone demethylase GASC1/KDM4C/JMJD2C hypomorphic mutant mice

GASC1, also known as KDM4C/JMJD2C, is a histone demethylase for histone H3 lysine 9 (H3K9) and H3K36. In this study, we observed an increase of GFAP‐positive astrocytes in the brain of Gasc1 hypomorphic mutant mice at 2–3 months of age, but not at postnatal day 14 and day 30 by immunohistochemistry. Increases of GFAP‐positive astrocytes were widely observed in the forebrain and prominent in such regions as cerebral cortex, caudate putamen, amygdala and diencephalon, but not obvious in hippocampus. Taken together with our observations to be published elsewhere that Gasc1 hypomorphic mutant mice exhibit abnormal behaviors including hyperactivity, persistence and many types of learning and memory deficits and abnormal synaptic functions such as prolonged long‐term potentiation, the increase in GFAP‐positive astrocytes may help understand their phenotypes, because astrocytes are known to affect synaptic plasticity.     

Propene polymerization with δ-TiCl3/AlCl(C2H5)2 and δ-TiCl3/Al(C2H5)3 catalyst systems, 1. Effect of external donors

The effect of ethyl benzoate (EB), diisobutyl phthalate (DIBP), dibutyl ether (DBE) and triethoxy(phenyl)silane (EPS) as third components on the propene polymerization with the catalyst systems δ-TiCl₃/AlCl(C₂H₅)₂ and δ-TiCl₃/Al(C₂H₅)₃ was investigated. The influence of external donors on the isotacticity, catalyst activity and average molecular weight (M _v) was tested. If external donors are employed, M _v decreases, the insoluble fraction in boiling isooctane increases and the catalyst activity is strongly influenced by the mole ratio external donor/TiCl₃. The results indicate that all external donors employed have the same qualitative effect on catalytic active centers.     

Association of complement allotype C4B2 with anterior uveitis

We have studied allotypes of the fourth component of complement (C4) in 44 patients with inflammatory eye disease in order to define genetic susceptibility factors further. Twenty-six patients had uveitis (18 had anterior uveitis) and 18 patients had retinal vasculitis. There was an increased incidence of the C4B2 allotype in patients with anterior uveitis (p_c < 0.002), especially in HLA B27 positive males. In contrast, there was no increased incidence of specific allotypes in patients with posterior uveitis or retinal vasculitis. This genetic association may form part of a disease susceptibility supratype in patients with anterior uveitis.     

Effect of radiographic contrast media on complement components C3 and C4: generation of C3b-like C3 and C4b-like C4

Various water soluble iodinated radiographic contrast media (RCM) have been studied for their effect on complement components C3 and C4, purified and in serum. Hepatotropic RCM, and at higher concentration also some nephrotropic RCM, were found to exert a direct effect on purified C3 and C4. RCM treated human C3 and C4 are characterized by (a) loss of haemolytic function, (b) retention of activity in the formation of fluid phase C3 convertases and (c) an antigenic relationship to activated C3 and C4 (C3b and C4b, respectively). This direct alteration of C3 and C4 can probably also occur in serum since loss of haemolytic function is observed at similar RCM concentrations after incubation of serum and of purified components. It is concluded that RCM treated C3 and C4 represent altered forms of these components that resemble C4b and C3b in activity and conformation (C3b-like C3 and C4b-like C4). The alteration is probably caused by binding of RCM, exerting a mild denaturing effect. C3b-like C3 is a potential activator of the alternative pathway, and both C3b-like C3 and C4b-like C4 are known to be cleaved by serum inactivators. A possible pathological significance of the generation of C3b-like C3, C4b-like C4 and their split products remains to be evaluated.     

人类补体C4表型与C4A：C4B比值关系初探

用激光薄层密度扫描仪对171份血清补体 C4的电泳色带进行扫描,并求取其 C4A:C4B 比值(R 值)。结果发现含 C4A·QO 基因者的 R 值范围0.068～0.429,平均0.228,而含 C4B·QO 基因者的 R 值范围2.197～9.334,平均3.973;在所检出的7例具有 C4B·座位重复基因的样本中.其 R 值均很小(0.120～0.625),且其中含有 C4A·QO 者与不含 C4A·QO 者的 R 值有明显差异.结果表明根据 R 值大小来指定C4·QO 基因和重复基因是有一定道理的.在最常见的 C4表型3,3/1,1中,其 R 值呈常态分布,但表型3,3/2,1、3,3/2,2和3,2/1,1的 R 值多大于1.0,而表型4,4/2,2和4,4/2,1的 R 值多小于1.0。两组表型的 R 值之间的两两比较有显著性差异(P<0.01)。