共查询到20条相似文献,搜索用时 15 毫秒
1.
Chronic inflammation induced by Helicobacter pylori infection is a critical factor in the development of peptic ulcer disease and gastric cancer. Central to this inflammation is the initiation of pro‐inflammatory signaling cascades within epithelial cells, in particular those mediated by two sensors of bacterial cell wall components, nucleotide‐binding oligomerization domain‐containing protein 1 (NOD1) and alpha‐protein kinase 1 (ALPK1). H pylori is, however, also highly adept at mitigating inflammation in the host, thereby restricting tissue damage and favoring bacterial persistence. H pylori modulates host immune responses by altering cytokine signaling in epithelial and myeloid cells, which results in increased proliferation of regulatory T cells and downregulation of effector T‐cell responses. H pylori vacuolating cytotoxin A (VacA) has been shown to play an important role in the dampening of immune responses and induction of immune tolerance capable of protecting against asthma. It is also possible to generate protective immune responses by immunization with various H pylori antigens or their epitopes, in combination with an adjuvant, though this for now has only been shown in mouse models. Novel non‐toxic adjuvants, consisting of modified bacterial enterotoxins or nanoparticles, have recently been developed that may not only enhance vaccine efficacy, but also help translate candidate vaccines to the clinic. This review will summarize the main discoveries in the past year regarding host immune responses to H pylori infection, as well as the design of new vaccine approaches against this infection. 相似文献
2.
A. Peter Castro 《American anthropologist》2003,105(1):187-189
Indians, Markets, and Rainforests: Theory, Methods, and Analysis. Ricardo A. Godoy. New York: Columbia University Press, 2001. 274 pp. 相似文献
3.
4.
5.
Loren A. Zech 《Mathematical biosciences》1984,72(2):407-414
Mones Berman's untimely death on 12 August 1982 put an end to his work in the development of theoretical biology. Arguments are examined, and it is concluded that a formal theory of lipoprotein metabolism flourished and expanded under the guidance of Dr. Berman. Not many scientists in the field of biology spend a major portion of their energies on theoretical work xxx was outstanding because of his early decision to follow the theoretical path. 相似文献
6.
Pericytes: developmental, physiological, and pathological perspectives, problems, and promises 总被引:3,自引:0,他引:3
Pericytes, the mural cells of blood microvessels, have recently come into focus as regulators of vascular morphogenesis and function during development, cardiovascular homeostasis, and disease. Pericytes are implicated in the development of diabetic retinopathy and tissue fibrosis, and they are potential stromal targets for cancer therapy. Some pericytes are probably mesenchymal stem or progenitor cells, which give rise to adipocytes, cartilage, bone, and muscle. However, there is still confusion about the identity, ontogeny, and progeny of pericytes. Here, we review the history of these investigations, indicate emerging concepts, and point out problems and promise in the field of pericyte biology. 相似文献
7.
Paul M. Peterson Konstantin Romaschenko Yolanda Herrera Arrieta Maria S. Vorontsova 《植物分类学报:英文版》2022,60(3):630-639
To investigate the evolutionary relationships among species of Afrotrichloris, Apochiton, Coelachyrum, Dinebra, Eleusine, Leptochloa, and Schoenefeldia of subtribe Eleusininae, a phylogeny based on DNA sequences from nine gene regions (ITS, rps16-trnK, rps3, rps16, rpoC2, rpl32-trnL, ndhF, ndhA, ccsA) is presented. Previous molecular phylogenies indicated that Coelachyrum was polyphyletic and Schoenefeldia was paraphyletic, with Afrotrichloris embedded within it. Apochiton burttii was embedded in the Coelachyrum clade paired with C. longiglume, Coelachyrumpoiflorum was placed outside of Coelachyrum and sister to Eleusine, and Schoenefeldia is paraphyletic, with its two species forming a grade sister to Afrotrichoris. Our molecular phylogeny supports recognition of a new genus, Schoenefeldiella, and a new combination, Schoenfeldiella transiens. In addition, we provide generic emendations for Coelachyrum, which now includes five species including a new combination proposed here, Coelachyrum burttii, and Eleusine, which now includes 11 species. 相似文献
8.
9.
10.
11.
Allophycocyanin: trimers,monomers, subunits,and homodimers 总被引:1,自引:0,他引:1
Allophycocyanin is a photosynthetic light-harvesting pigment-protein complex located in the phycobilisomes of cyanobacteria and red algae. Using dynamic light scattering and circular dichroism, solutions of purified allophycocyanin were shown to consist of homogeneous trimers (alpha3beta3) with a nonspherical shape over a very wide range of protein concentrations at pH 6.0 and 20 degrees C. Deconvolutions of the visible circular dichroism spectrum of the trimer were carried out for the first determination of the individual spectra of all six-component chromophores. The chromophores were shown to be in different microenvironments that helped determine the spectrum of the trimer. Monomers (alpha beta) that were formed in either the presence of 0.50M NaSCN or at 45 degrees C were shown to be completely reversible to trimers. However, subunits (alpha and beta) that were formed in either the presence of 8M urea or at 60 degrees C, using spectroscopy and gel-filtration column chromatography, were observed to only partially reconstitute trimers. Homodimers (alpha2 and/or beta2) formed during the regeneration of trimers. The homodimer, which was detected for the first time when both subunits were present, was shown to be in equilibrium with its subunits. Unlike the trimer situation, subunits were found to fully reconstitute monomers in the presence of 0.50M NaSCN. These results suggest a route to trimer assembly from subunits with monomers serving as intermediaries and the homodimers forming in a nonproductive step that did not interfere with the overall assembly scheme. 相似文献
12.
Seán Ó. Nualláin 《Biosemiotics》2008,1(2):239-251
Over the past half-century, the Freeman laboratory has accumulated a large volume of data and a correspondingly extensive
interpretive framework centered around an alternative perspective on brain function, that of dynamical systems. The purpose
of this paper is first briefly to summarise this work, and bring it into dialogue with other perspectives. The contents of
consciousness are seen as an inevitably sparse sample of events in the perception–action cycle. The paper proceeds to an attempt
to elucidate the contents of this sparse sample. A critical concept is that of selfhood, and how it presents itself phenomenologically.
It is argued that our experience of selfhood is an artifact of the necessity of preservation of subject/object relations.
As this part of metaphysics has been badly misunderstood, we scrutinise it at some length in quantum mechanics, biology, and
cognition. It is argued that Pattee's approach, while valuable, tends to premature closure on these issues. The paper then
proceeds to outline a view on how selfhood is best considered wrt the immune response. This is interrelated with phenomenology,
and some data are adduced to support this central hypothesis. Finally, consequences for the social sciences in general are
hinted at. 相似文献
13.
14.
15.
MicroRNAs: genomics, biogenesis, mechanism, and function 总被引:463,自引:0,他引:463
MicroRNAs (miRNAs) are endogenous approximately 22 nt RNAs that can play important regulatory roles in animals and plants by targeting mRNAs for cleavage or translational repression. Although they escaped notice until relatively recently, miRNAs comprise one of the more abundant classes of gene regulatory molecules in multicellular organisms and likely influence the output of many protein-coding genes. 相似文献
16.
Smeeth L 《BMJ (Clinical research ed.)》2000,320(7246):1384
17.
18.
The basic data on hyperprolactinemia (i.e. an excess of PRL above a reference laboratory's upper limits), the most common endocrine disorder of the hypothalamic-pituitary axis are given in this review. The following issues are discussed: regulation of prolactin (Prl) secretion, definition of hyperprolactinemia, its etiology and pathogenesis as well as its symptoms, diagnosis, and treatment (including medical and surgical therapy). It should be stressed that finding of elevated PRL serum concentrations constitute the beginning of diagnostic procedure and, after exclusion of physiologic, pharmacologic, and other organic causes of increased PRL levels, should be followed by detailed diagnosis including MRI. In patients in whom hyperprolactinemia has been confirmed the treatment with dopamine agonists (with prevalence of cabergoline, followed by quinagoline) is currently considered first-choice therapy. Surgery should be performed only in the patients resistant or intolerant to these agents, or in patients who refuse long-term therapy. 相似文献
19.
20.