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排序方式: 共有124条查询结果,搜索用时 15 毫秒
21.
Retinopathy of prematurity (ROP) is a vasoproliferative disorder that occurs in premature infants and may lead to permanent visual impairment. We investigated both the possible protective role of N-acetyl cysteine (NAC) for preventing ROP and the role of IGF-1 in the disorder. Forty-five newborn rats were divided into three groups. Group 1 was raised in room air as controls. Group 2 was exposed to 60% oxygen for 14 days after birth, then transferred to room air. Group 3 was exposed to the same conditions as group 2, but received intraperitoneal injections of NAC on postnatal days 7–17. After 35 days, both eyes of all rats were processed for histology. Some sections were stained with hematoxylin and eosin to assess structural changes and other sections were immunostained to determine the location of IGF-1. Frozen sections also were prepared and stained for adenosine triphosphatase to detect retinal blood vessels. Compared to the controls, more blood vessels, many of which were abnormal, and increased IGF-1 expression were observed in group 2. In group 3, abnormal blood vessels and IGF-1 expression were less evident. NAC appeared to be an effective vascular-protective agent for ROP by decreasing IGF-1 expression. 相似文献
22.
Teng YK Verburg RJ Verpoort KN Diepenhorst GM Bajema IM van Tol MJ Jol-van der Zijde EC Toes RE Huizinga TW van Laar JM 《Arthritis research & therapy》2007,9(5):R106
In order to identify pathogenic correlates of refractory rheumatoid arthritis (RA), antibodies against anti-cyclic citrullinated
protein (ACPAs) were investigated in RA patients in whom the dysregulated immune system had been ablated by high-dose chemotherapy
(HDC) and autologous haematopoietic stem cell transplantation (HSCT). Six patients with refractory RA were extensively characterized
in terms of levels of total immunoglobulins, RA-specific autoantibodies (ACPAs and rheumatoid factor) and antibodies against
rubella, tetanus toxoid (TT) and phosphorylcholine before and after HDC plus HSCT. Additionally, the avidity of ACPAs was
measured before and after treatment and compared with the avidity of TT antibodies following repeated immunizations. Synovial
biopsies were obtained by arthroscopy before HDC plus HSCT, and analyzed by immunohistochemistry. In the three patients with
clinically long-lasting responses to HDC plus HSCT (median 423 days), significant reductions in ACPA-IgG levels after therapy
were observed (median level dropped from 215 to 34 arbitrary units/ml; P = 0.05). In contrast, stable ACPA-IgG levels were observed in three patients who relapsed shortly after HDC plus HSCT (median
of 67 days). Clinical responders had ACPA-IgG of lower avidity (r = 0.75; P = 0.08) and higher degree of inflammation histologically (r = 0.73; P = 0.09). Relapse (after 38 to 530 days) in all patients was preceded by rising levels of low avidity ACPA-IgG (after 30 to
388 days), in contrast to the stable titres of high avidity TT antibodies. In conclusion, humoral autoimmune responses were
differentially modulated by immunoablative therapy in patients with synovial inflammation and low avidity ACPA-IgG autoantibodies
as compared with patients with high levels of high avidity ACPA-IgG. The distinct clinical disease course after immunoablative
therapy based on levels and avidity of ACPA-IgG indicates that refractory RA is not a single disease entity. 相似文献
23.
Sherwin J. Abraham Tomoyoshi Kobayashi R. John Solaro Vadim Gaponenko 《Journal of biomolecular NMR》2009,43(4):239-246
Reductive methylation of lysine residues in proteins offers a way to introduce 13C methyl groups into otherwise unlabeled molecules. The 13C methyl groups on lysines possess favorable relaxation properties that allow highly sensitive NMR signal detection. One of
the major limitations in the use of reductive methylation in NMR is the signal overlap of 13C methyl groups in NMR spectra. Here we show that the uniform influence of the solvent on chemical shifts of exposed lysine
methyl groups could be overcome by adjusting the pH of the buffering solution closer to the pKa of lysine side chains. Under
these conditions, due to variable pKa values of individual lysine side chains in the protein of interest different levels
of lysine protonation are observed. These differences are reflected in the chemical shift differences of methyl groups in
reductively methylated lysines. We show that this approach is successful in four different proteins including Ca2+-bound Calmodulin, Lysozyme, Ca2+-bound Troponin C, and Glutathione S-Transferase. In all cases significant improvement in NMR spectral resolution of methyl
signals in reductively methylated proteins was obtained. The increased spectral resolution helps with more precise characterization
of protein structural rearrangements caused by ligand binding as shown by studying binding of Calmodulin antagonist trifluoperazine
to Calmodulin. Thus, this approach may be used to increase resolution in NMR spectra of 13C methyl groups on lysine residues in reductively methylated proteins that enhances the accuracy of protein structural assessment.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
24.
EM Tazi I Lalya MF Tazi Y Ahellal H M'rabti H Errihani 《World journal of surgical oncology》2010,8(1):1-3
Goblet cell carcinoid of the large intestine is a rare neoplasm, usually located in ascending colon and rectum. A 60-year-old male patient underwent surgery after the diagnosis of acute abdomen. Exploratory laparotomy revealed perforation with a diameter of 1 cm at the site of the previously performed gastroenterostomy and dilatation of the right colic flexure, secondary to a solid obstructive mass located in the mid-portion of transverse colon. Histopathological investigation of the biopsies, taken from the gastroenterostomy site and the tumor, revealed mixed carcinoid-adenocarcinoma with carcinoid component, predominantly composed of goblet cells. Three cycles of FOLFOX-4 protocol was administered. Following respiratory distress secondary to pulmonary metastasis, the patient's condition deteriorated and subsequently died in the fourth postoperative month. Our aim with this paper is to point out that more cases should be reported for more effective diagnosis, histopathological study, clinical investigation, treatment and prognosis of this specific neoplasm. 相似文献
25.
Irene EM Bultink 《Arthritis research & therapy》2010,12(1):107
Cardiovascular disease (CVD) has been identified as a major contributor to morbidity and mortality in patients with systemic
lupus erythematosus (SLE). The etiology of premature CVD in SLE is supposed to have many factors, including traditional coronary
artery disease (CAD) risk factors, antiphospholipid antibodies, and metabolic and inflammatory factors. Despite the overwhelming
interest in CVD in SLE research, prospective studies evaluating risk factors for hard endpoints (that is, cardiovascular events)
are relatively scarce. The article by Gustafsson and colleagues suggests that prothrombotic factors play an important role
in SLE-related CVD and that the influence of traditional CAD risk factors might be limited. 相似文献
26.
Polygalacturonase inhibiting protein (PGIP) is localized in plant cell walls and plays an important role both in pectic substance metabolism and in prevention of the penetration of phytopathogenic microorganisms. Apparently, PGIP is responsible for the specificity of cell--cell interactions during pollination or inoculation by fungi nonpathogenic for the particular plant. PGIPs from different plants share a basic common structure. They are rather thermostable glycoproteins enriched with leucine and contain about 20% carbohydrates; the molecular weight varies between 37-54 kD. The synthesis of PGIP is encoded by one gene, and its expression is stimulated by injury and fungal infection. The resistance of plant tissues to infection frequently correlates with PGIP expression and with inhibiting action on fungal PG. Thus, PGIP is believed to be useful for gene engineering to obtain transgenic plants resistant to fungal infection or retaining commercial value during storage. 相似文献
27.
First-egg date fluctuations for the Pied Flycatcher Ficedula hypoleuca in the woodlands of mid-Wales in the twentieth century 总被引:1,自引:1,他引:0
EM. SLATER 《Ibis》1999,141(3):497-499
28.
Cardiac troponin I(129-149) binds to the calcium saturated cardiac troponin C/troponin I(1-80) complex at two distinct sites. Binding of the first equivalent of troponin I(129-149) was found to primarily affect amide proton chemical shifts in the regulatory domain, while the second equivalent perturbed amide proton chemical shifts within the D/E linker region. Nitrogen-15 transverse relaxation rates showed that binding the first equivalent of inhibitory peptide to the regulatory domain decreased conformational exchange in defunct calcium binding site I and that addition of the second equivalent of inhibitory peptide decreased flexibility in the D/E linker region. No interactions between the inhibitory peptide and the C-domain of cardiac troponin C were detected by these methods demonstrating that the inhibitory peptide cannot displace cTnI(1-80) from the C-domain. 相似文献
29.
Gaponenko V Howarth JW Columbus L Gasmi-Seabrook G Yuan J Hubbell WL Rosevear PR 《Protein science : a publication of the Protein Society》2000,9(2):302-309
We describe a simple experimental approach for the rapid determination of protein global folds. This strategy utilizes site-directed spin labeling (SDSL) in combination with isotope enrichment to determine long-range distance restraints between amide protons and the unpaired electron of a nitroxide spin label using the paramagnetic effect on relaxation rates. The precision and accuracy of calculating a protein global fold from only paramagnetic effects have been demonstrated on barnase, a well-characterized protein. Two monocysteine derivatives of barnase, (H102C) and (H102A/Q15C), were 15N enriched, and the paramagnetic nitroxide spin label, MTSSL, attached to the single Cys residue of each. Measurement of amide 1H longitudinal relaxation times, in both the oxidized and reduced states, allowed the determination of the paramagnetic contribution to the relaxation processes. Correlation times were obtained from the frequency dependence of these relaxation processes at 800, 600, and 500 MHz. Distances in the range of 8 to 35 A were calculated from the magnitude of the paramagnetic contribution to the relaxation processes and individual amide 1H correlation times. Distance restraints from the nitroxide spin to amide protons were used as restraints in structure calculations. Using nitroxide to amide 1H distances as long-range restraints and known secondary structure restraints, barnase global folds were calculated having backbone RMSDs <3 A from the crystal structure. This approach makes it possible to rapidly obtain the overall topology of a protein using a limited number of paramagnetic distance restraints. 相似文献
30.
Antibodies to citrullinated proteins and differences in clinical progression of rheumatoid arthritis
van der Helm-van Mil AH Verpoort KN Breedveld FC Toes RE Huizinga TW 《Arthritis research & therapy》2005,7(5):R949-R958
Antibodies to citrullinated proteins (anti-cyclic-citrullinated peptide [anti-CCP] antibodies) are highly specific for rheumatoid
arthritis (RA) and precede the onset of disease symptoms, indicating a pathogenetic role for these antibodies in RA. We recently
showed that distinct genetic risk factors are associated with either anti-CCP-positive disease or anti-CCP-negative disease.
These data are important as they indicate that distinct pathogenic mechanisms are underlying anti-CCP-positive disease or
anti-CCP-negative disease. Likewise, these observations raise the question of whether anti-CCP-positive RA and anti-CCP-negative
RA are clinically different disease entities. We therefore investigated whether RA patients with anti-CCP antibodies have
a different clinical presentation and disease course compared with patients without these autoantibodies. In a cohort of 454
incident patients with RA, 228 patients were anti-CCP-positive and 226 patients were anti-CCP-negative. The early symptoms,
tender and swollen joint count, and C-reactive protein level at inclusion, as well as the swollen joint count and radiological
destruction during 4 years of follow-up, were compared for the two groups. There were no differences in morning stiffness,
type, location and distribution of early symptoms, patients' rated disease activity and C-reactive protein at inclusion between
RA patients with and without anti-CCP antibodies. The mean tender and swollen joint count for the different joints at inclusion
was similar. At follow-up, patients with anti-CCP antibodies had more swollen joints and more severe radiological destruction.
Nevertheless, the distribution of affected joints, for swelling, bone erosions and joint space narrowing, was similar. In
conclusion, the phenotype of RA patients with or without anti-CCP antibodies is similar with respect to clinical presentation
but differs with respect to disease course. 相似文献