首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 63 毫秒
1.
Ro (SSA) and La (SSB) antibodies   总被引:2,自引:0,他引:2  
Summary This review traces the historical development of information regarding the Ro (SSA) and La (SSB) autoantibody systems over the past twenty years. Clinical and serologic findings are integrated with fundamental observations in this rapidly expanding area of research. Retrospective analysis of the physicochemical properties of the antigens and the cellular staining characteristics of antibodies to these antigens suggest that SjD and Ro and SSA, as well as SjT and La, SSB, and Ha antigens probably are similar macromolecules. The immunologic identity of Ro with SSA and La with SSB and Ha has been established previously. Antibodies to these antigens are directed against macromolecules containing small RNA nucleotides.Antibodies to the Ro (SSA)-La(SSB) antigen system commonly are detected in the sera of patients with systemic lupus erythematosus and Sjögren's syndrome and appear to be of diagnostic significance. These antibodies occur in up to one quarter of patients with systemic lupus erythematosus (SLE) without the sicca complex, but also in patients with ANA negative SLE who have a prominent photosensitive dermatitis and may have serious renal disease, subacute cutaneous SLE, and in infants and mothers of infants with neonatal SLE. Thus, these antibody systems form a serologic link between many unusual connective tissue diseases and systemic SLE.Antibodies to Ro (SSA)-La(SSB) are associated not only with Sjögren's syndrome occurring alone, but also with Sjögren's syndrome occurring in the setting of other connective tissue diseases including SLE and rheumatoid arthritis. Anemia, leukopenia, and thrombocytopenia, as well as hyperglobulinemia and the presence of rheumatoid factor, cryoglobulins, and antibodies to nuclear antigens are associated significantly with Ro positivity in Sjögren's syndrome patients. There is a striking association of vasculitis in the clinical setting of Sjögren's syndrome with the presence of antibodies to Ro (SSA). In addition to peripheral nerve involvement, unusual central nervous system manifestations as well as myositis occur in these Ro(SSA) positive Sjögren's syndrome patients. Deposition of immunoglobulin and complement within vessel walls of kidney and muscle from Ro positive patients with Sjögren's syndrome suggests a possible role for immune complex deposition in the pathogenesis of the vasculitis.Supported by National Institutes of Health grant 5ROI-AM-25650-03 and Research Career Development Award 5-KO-4-AM-00524-02  相似文献   

2.
3.
4.
Pendant-type poly(4-vinylpyridine) (PVP)-Cr(III) complexes ( 1 ) and -Co(III) complexes ( 2 ) with various degrees of coordination (x) were prepared, and the structures and properties of the polymer complexes are discussed. The magnetic susceptibility of 1 showed that 1 is paramagnetic and that the Cr(III) ions do not interact with each other, although they were coordinated along the PVP chain at high concentration. The far-infrared absorption bands, assigned to the stretching of the coordinative bond between Co and the pyridine-unit of PVP shifted to lower wave numbers in 2 , as compared with the corresponding pyridine complex 4 . It is thus considered that the coordinative bond in 2 is weaker than in the monomeric pyridine complex 4 , owing to the steric hindrance of PVP; the Co(III) chelates coordinated at high concentration. This consideration is supported by the ESR parameters of 1 . The dissociation temperature of the coordinative bond between Co and PVP increased with x. It is presumed that the PVP complex 2 has a rigid structure such that more energy is required to break the coordinative bond.  相似文献   

5.
Joubert syndrome (JS) and related disorders are characterized by the 'molar tooth sign' (cerebellar vermis hypoplasia and brainstem anomalies) on MRI, hypotonia, developmental delay, ataxia, irregular breathing pattern and abnormal eye movements. Combinations of additional features such as polydactyly, ocular coloboma, retinal dystrophy, renal disease, hepatic fibrosis, encephalocele, and other brain malformations define clinical sub-types. Recent identification of the NPHP1, AHI1, and CEP290 genes has started to reveal the molecular basis of JS, which may implicate the primary cilium in these disorders. Additional genes remain to be identified.  相似文献   

6.
Tumor necrosis factor (TNF-alpha) and lymphotoxin (TNF-beta).   总被引:4,自引:0,他引:4  
  相似文献   

7.
8.
Loo JS  Ooi CP  Boey FY 《Biomaterials》2005,26(12):1359-1367
This paper seeks to examine the effects of electron beam (e-beam) radiation on biodegradable polymers (PLGA and PLLA), and to understand their radiation-induced degradation mechanisms. PLGA (80:20) and PLLA polymer films were e-beam irradiated at doses from 2.5 to 50 Mrad and the degradation of these films were studied by measuring the changes in their molecular weights, FTIR spectra, thermal and morphological properties. The dominant effect of e-beam irradiation on both PLGA and PLLA is chain scission. Chain scission occurs first through scission of the polymer main chain, followed by hydrogen abstraction. Chain scission, though responsible for the reduction in the average molecular weight, Tc, Tg and Tm of both polymers, encourages crystallization in PLGA. PLLA also undergoes chain scission upon irradiation but to a lesser degree compared to PLGA. The higher crystallinity of PLLA is the key factor in its greater stability to e-beam radiation compared to PLGA. A linear relationship is also established between the decrease in molecular weight with respect to radiation dose.  相似文献   

9.
10.
Loh XJ  Colin Sng KB  Li J 《Biomaterials》2008,29(22):3185-3194
Thermo-responsive multiblock poly(ester urethane)s comprising poly(epsilon-caprolactone) (PCL), poly(ethylene glycol) (PEG), and poly(propylene glycol) (PPG) segments were synthesized. The copolymers were characterized by GPC, NMR, FTIR, XRD, DSC and TGA. Water-swelling analysis carried out at different temperatures revealed that the bulk hydrophilicity of the copolymers could be controlled either by adjusting the composition of the copolymer or by changing the temperature of the environment. These thermo-responsive copolymer films formed highly swollen hydrogel-like materials when soaked in cold water and shrank when soaked in warm water. The changes are reversible. The mechanical properties of the copolymer films were assessed by tensile strength measurement. These copolymers were ductile when compared to PCL homopolymers. Young's modulus and the stress at break increased with increasing PCL content, whereas the strain at break increased with increasing PEG content. The results of the cytotoxicity tests based on the ISO 10993-5 protocol demonstrated that the copolymers were non-cytotoxic and could be potentially used in biomedical applications.  相似文献   

11.
Summary Eggshell formation in Caryophyllaeus laticeps and Caryophyllaeides fennica (Cestoidea: Caryophyllaeidea), as shown by histochemical tests for proteins, phenols, and polyphenol oxidase, is similar to that of D. latum, Ligula sp., and Schistocephalus sp.Maturation of vitelline cells is characterized by (1) an increase in size of two or three times, (2) vacuolation of the nucleus with the nucleolus and a small amount of nucleoplasm and dispersed chromatin displaced to one side, and in the cytoplasm, (3) synthesis of shell globules that are later released in the uterus to form the shell.Tests for glycogen (PAS) and nucleic acids show that maturing and mature cells have glycogen in the nuclear vacuole and cytoplasm and that there is a decrease in DNA in the nucleus and an increase in RNA in the cytoplasm as protein synthesis is initiated.Glycogenesis and protein synthesis appear to be largely completed before the cell is released from the follicle.
Zusammenfassung Die Eischalenbildung bei Caryophyllaeus laticeps und Caryophyllaeides fennica (Cestoidea: Caryophyllaeidea) ist — wie die histochemischen Untersuchungen auf Proteine, Phenol und Polyphenoloxidase zeigen — ähnlich der bei D. latum, Ligula spec. und Schistocephalus spec. Die Reifung der Dotterzellen ist charakterisiert 1. durch eine Vergrößerung auf das Zwei- bis Dreifache, 2. eine Vakuolisation des Zellkerns mit Nukleolus und einer kleinen Menge von Nukleoplasma und fein verteiltem Chromatin, das sich auf eine Seite verlagert, und im Cytoplasma, 3. Synthese der Schalenkügelchen, die später in den Uterus zur Schalenbildung freigesetzt werden.Die Teste auf Glykogen (PAS) und Nukleinsäuren zeigen, daß die reifenden und die reifen Zellen in den Kernvakuolen und Zytoplasma Glykogen enthalten, und daß eine Verminderung der DNS im Nukleus und eine Vermehrung der RNS im Zytoplasma auftritt, wenn die Proteinsynthese beginnt.Die Glykogenese und die Proteinsynthese erscheint im wesentlichen abgeschlossen zu sein, bevor die Zelle aus dem Follikel entlassen wird.


This investigation was started at Neuchâtel and finished at Albany.

NIH Postdoctoral fellow.  相似文献   

12.
The translocation of synaptic Zn(2+) from nerve terminals into selectively vulnerable neurons may contribute to the death of these neurons after global ischemia. We hypothesized that cellular Zn(2+) overload might be lethal for reasons similar to cellular Ca(2+) overload and tested the hypothesis that Zn(2+) neurotoxicity might be mediated by the activation of nitric oxide synthase. Although Zn(2+) (30-300microM) altered nitric oxide synthase activity in cerebellar extracts in solution, it did not affect nitric oxide synthase activity in cultured murine neocortical neurons. Cultured neurons exposed to 300-500microM Zn(2+) for 5min under depolarizing conditions developed widespread degeneration over the next 24h that was unaffected by the concurrent addition of the nitric oxide synthase inhibitor N(G)-nitro-L-arginine. Furthermore, Zn(2+) neurotoxicity was attenuated when nitric oxide synthase activity in the cultures was induced by exposure to cytokines, exogenous nitric oxide was added or nitric oxide production was pharmacologically enhanced. The unexpected protective effect of nitric oxide against Zn(2+) toxicity may be explained, at least in part, by reduction of toxic Zn(2+) entry. Exposure to nitric oxide donors reduced Ba(2+) current through high-voltage activated calcium channels, as well as K(+)-stimulated neuronal uptake of 45Ca(2+) or 65Zn(2+). The oxidizing agents thimerosal and 2,2'-dithiodipyridine also reduced K(+)-stimulated cellular 45Ca(2+) uptake, while akylation of thiols by pretreatment with N-ethylmaleimide blocked the reduction of 45Ca(2+) uptake by a nitric oxide donor.The results suggest that Zn(2+)-induced neuronal death is not mediated by the activation of nitric oxide synthase; rather, available nitric oxide may attenuate Zn(2+) neurotoxicity by reducing Zn(2+) entry through voltage-gated Ca(2+) channels, perhaps by oxidizing key thiol groups.  相似文献   

13.
The radical copolymerization of styrene with Zn(II), Co(II), Ni(II) and Cu(II) acrylates in methanol at 60°C was studied and that of styrene with Cu(II) acrylate also in acetonitrile at 80°C. In a given period of time an increase of conversion was observed with increasing concentration of the first three metal acrylates in mixtures with styrene. With Cu(II) acrylate, however, a decrease of conversion was found. The monomer reactivity ratios were determined as follows: rSt = 1,10, r = 0,90; rSt = 1,74, r = 0,56; rSt = 1,83, r = 0,53; rSt = 5,94, r = 0,12 (in acetonitrile). The products of the reactivity ratios, almost equal to one, reflect an “ideal” copolymerization and therefore a very little alternating tendency in propagation reactions. The Alfrey-Price Q-e parameters for the metal acrylates were calculated and discussed.  相似文献   

14.
15.
A method suitable for transfer of poly(epsilon-caprolactone) and poly(L-lactide) microspheres (synthesized by pseudoanionic dispersion polymerization of epsilon-caprolactone and L-lactide in heptane-1,4-dioxane mixed solvent) from heptane to water was developed. This method consists of treating the microspheres with KOH-ethanol in the presence of surfactants (nonionic Triton X-405, anionic sodium dodecyl sulfate (SDS), and zwitterionic ammonium sulfobetaine-2 (ASB)). Partial hydrolysis of polyesters results in the formation of hydroxyl and carboxyl groups in the surface layer of microspheres and enhances their stability in water-based media. Minimal concentrations of surfactants, needed to obtain stable suspensions of particles, were equal to 3 x 10(-2) and 6 x 10(-2), and 3 x 10(-2) mol l(-1) for Triton X-405. SDS, and ASB, respectively. In the case of poly(epsilon-caprolactone) microspheres, suspensions in water were stable for all three surfactants for pH values ranging from 3 to 11. Suspensions of poly(L-lactide) were stable in the same range of pH values only for ASB. Surface charge density determined by electrophoretic mobility varied for poly(epsilon-caprolactone) microspheres from 2.6 x 10(-7) to 8.9 x 10(-7) mol m(-2), for particles stabilized with Triton X-405 and ASB. respectively. In the case of poly(L-lactide) microspheres, surface charge density varied from 3.9 x 10(-7) (stabilizer: Triton X-405) to 7.4 x 10(-7) mol m(-2) (stabilizer: ASB). Carboxyl groups located in the surface layer of poly(L-lactide) microspheres were used for covalent immobilization of 6-aminoquinoline, a fluorophore with an amino group. Maximum surface concentration of immobilized 6-aminoquinoline was equal to 1.9 x 10(-6) mol m(-2). Poly(epsilon-caprolactone) microspheres transferred into water were loaded with ethyl salicylate. Loading up to 38% (w/w) was obtained.  相似文献   

16.
Cr(VI) is a human and animal carcinogen. Cr(VI) does not interact directly with DNA and thus its genotoxicity is attributed to its intracellular reduction to Cr(III) via reactive intermediates. The resulting types of DNA damage can be grouped into two categories: (1) oxidative DNA damage and (2) Cr(III)-DNA interactions. This study examines the molecular mechanism of Cr(VI) and Cr(III) genotoxicity in an intact cell. A system screening for DNA deletions (DEL assay) was used to compare induction of chromosomal rearrangements in the yeast Saccharomyces cerevisiae following Cr(VI) and Cr(III) exposure. Both forms of chromium induced DNA deletions albeit with different dose-response curves. N-acetylcysteine had a protective effect against Cr(VI) genotoxicity at high exposure doses but had no protective effect at lower doses or against Cr(III). An oxidative DNA damage repair mutant was hypersensitive to Cr(VI) only at high exposure and the mutant was not hypersensitive to Cr(III) exposure. These data imply that oxidative stress is involved in Cr(VI) genotoxicity at high exposure concentrations and not so in Cr(III). The Cr(III)-DNA interaction appears to be an important genotoxic lesion following Cr(VI) exposure at low-exposure concentrations. The CAN forward mutation assay revealed that within the concentration ranges used for this study, Cr(III) does not cause point mutations and Cr(VI) causes a mild but statistically significant increase in point mutation only at the highest concentration tested. This study reveals that DNA deletions occurring as a result of intrachromosomal homologous recombination are a useful endpoint for studying chromium genotoxicity.  相似文献   

17.
Fatalities from immunotherapy (IT) and skin testing (ST)   总被引:12,自引:1,他引:11  
The Committee on Allergen Standardization of the American Academy of Allergy and Immunology obtained information about 46 fatalities that had occurred during immunotherapy (IT) or skin testing (ST) since 1945. Sufficient information for complete analysis was provided for 30 patients (six for ST and 24 for IT). Of the 30 fatalities, there were 15 male and 15 female fatalities ranging in age from 7 to 70 years (x = 33 years). Known errors of administration accounted for three and possibly an additional three fatalities. Ten fatalities occurred during seasonal exacerbation of the patient's disease, four in patients who had been symptomatic at the time of the injection, two of whom had been receiving beta-adrenergic blockers. Of the 24 fatalities associated with IT, four had experienced previous reactions, 11 manifested a high degree of sensitivity, and four had been injected with newly prepared extracts. Fifteen of the 30 fatalities had received pollen extracts as part of the fatal injection. Of the six fatalities associated with ST, five were due to intradermal testing without prior puncture testing. The signs and symptoms were variable and did not indicate that death was imminent nor predict the cause of death. The time to onset of the reaction was less than 30 minutes in 22/30, more than 30 minutes in 3/30, and not reported in 5/30. The cause of death in 14/16 patients with asthma was respiratory. Epinephrine had been administered to 18, not administered to three, and was either not recorded or unknown in the remaining nine patients. Since seven to 10 million allergen injections are administered yearly, the risk of a fatal reaction is low and may be lessened even further as additional precautions are taken in the selection and treatment of allergic patients and in improved treatment of the anaphylactic reactions.  相似文献   

18.
19.
In order to study the repertoire of poly(Tyr,Glu)-poly(DLAla)--poly(Lys) [(T,G)-A--L] specific antibodies, monoclonal antibodies were prepared by fusing myeloma cells with spleen cells from C3H.SW mice immunized with (T,G)-A--L and boosted with (Tyr-Tyr-Glu-Glu)-poly(DLAla)--poly(Lys)](T-T-G-G)-A--L]. Eleven clones which secreted homogeneous antibodies were obtained. In general, two families of monoclonal antibodies were detected: those which bind exclusively (T-T-G-G)-A--L and those which bind both (T-T-G-G)-A--L and (T,G)-A--L. Analysis for idiotypic expression revealed that only two antibodies (clones no. 103 and 160), which were found to be similar in their fine specificity, cross-reacted with antibodies against the major idiotypes of (T,G)A--L specific antibodies. Guinea-pig antibodies against clone no. 160 reacted with the polyclonal (T,G)-A--L specific antibodies, whereas antibodies against 103 monoclonal antibodies did not react with C3H.SW anti-(T,G)-A--L antibodies, but did cross-react with four other monoclonal antibodies. It appears that the idiotypic determinants expressed on polyclonal (T,G)-A--L specific antibodies are heterogeneous, and consist of at least two serologically different idiotypes detected by clones no. 103 and 160.  相似文献   

20.
目的:合成一种新型的带有反应活性基团的聚(乳酸-赖氨酸)共聚物,以改善聚乳酸的细胞亲和性。方法:以N^ε-苄氧羰基-L-赖氨酸和溴乙酰溴为起始原料,合成了单体3S-[4-(苄氧羰基氨基)丁基]-吗啉-2,5-二酮,再以辛酸亚锡为催化剂,通过3S-[4-(苄氧羰基氨基)丁基]-吗啉-2,5-二酮与D,L-丙交酯共聚,制备了聚(羟基乙酸-N^ε-苄氧羰基-L-赖氨酸-乳酸),并用FT-IR,^1H-NMR,^13C-NMR对反应产物进行了表征。结果:FT-IR,^1H-NMR,^13C-NMR谱图表明各步反应产物的生成,根据^1H-NMR谱图中质子峰的积分面积之比得到共聚物中各单体的摩尔分数。结论:N^ε-苄氧羰基-L-赖氨酸被成功引入到聚乳酸主链中,且共聚物中各组分的含量可通过投料比的不同在较大范围内进行调节。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号