The importance of smooth muscle cells in the development of foam cells in the gastric mucosa

Summary Foam cells in lipid islands of the stomach can develop from both histiocytes and smooth muscle cells. With increasing storage of lipid vacuoles in smooth muscle cells, loosening of the myofilament arrangement and decrease of the dense areas subjacent to the plasma membrane occurs. Endoplasmic reticulum and the cisternae of the Golgi-apparatus dilate, the cell organelles increase initially and the basement membrane of the smooth muscle cells is fragmentarily formed. Only in incompletely formed foam cells can the origin from smooth muscle cells be recognised, in their final state their histiogenesis is seldom apparent.The authors are grateful to H. Gerdes for leaving the specimens and to R. Naumann and H. Staubitz for technical and photographic assistance.     

人成釉细胞瘤中端粒酶反转录酶启动子区的DNA甲基化

目的研究成釉细胞瘤（ameloblastoma，AB）中hTERT启动子区的DNA甲基化，并探讨其生物学意义。方法选取新鲜标本AB12例，同时用11例正常黏膜做对照观察，用甲基化特异PCR检测上述组织中人类端粒酶反转录酶（human telomerase reverse transcripase，hTERT）启动子区的DNA甲基化。结果AB、正常黏膜中hTERT启动子区的DNA非甲基化阳性分别为4例（4／12）和6例（6／11）。AB、正常黏膜中hTERT启动子区的DNA甲基化阳性分别为11例（11／12）和3例（3／11），其中4例AB和1例正常黏膜同时表现hTERT启动子区DNA的甲基化和非甲基化。结论AB的hTERT启动子区的DNA甲基化比正常黏膜常见且有意义；hTERT启动子的甲基化可能对hTERT基因起调节作用。     

Array-based DNA methylation profiling in acute myeloid leukaemia

Methylation in the promoter region of many genes is involved in regulating gene expression patterns. Using the Illumina GoldenGate^© methylation assay, we examined the methylation status of 1505 CpG‐sites from 807 genes in 32 samples from patients with acute myeloid leukaemia (AML) at diagnosis, nine at relapse and 15 normal controls and performed additional pyrosequencing and semiquantitative methylation specific polymerase chain reaction (MSP) of the GNMT promoter in 113 diagnostic AML samples. We found a gain of overall methylation in AML samples with a further increase at relapse. Regional hypermethylation as assessed by array analysis could be confirmed by both MSP and pyrosequencing. Additionally, large‐scale methylation analysis identified interesting candidate genes. Cluster analysis indicated that cytogenetic subgroups seemed to be characterized by additional distinct epigenetic modifications and that basic DNA methylation patterns remain at relapse. Therefore, promoter hypermethylation is a frequent event in AML and is accentuated at relapse. Array‐based methylation analysis determined distinct methylation profiles for non‐malignant controls and AML samples with specific chromosomal aberrations and can identify target genes for further evaluation.     

Polycomb eviction as a new distant enhancer function

Remote distal enhancers may be located tens or thousands of kilobases away from their promoters. How they control gene expression is still poorly understood. Here, we analyze the influence of a remote enhancer on the balance between repression (Polycomb-PcG) and activation (Trithorax-TrxG) of a developmentally regulated gene associated with a CpG island. We reveal its essential, nonredundant role in clearing the PcG complex and H3K27me3 from the CpG island. In the absence of the enhancer, the H3K27me3 demethylase (JMJD3) is not recruited to the CpG island. We propose a new role of long-range regulatory elements in removing repressive PcG complexes.     

Bisulfite genomic sequencing to uncover variability in DNA methylation: Optimized protocol applied to human T cell differentiation genes

DNA methylation, which most commonly occurs at the C5 position of cytosines within CpG dinucleotides, is one of several epigenetic mechanisms that cells use to control gene expression. The importance of DNA methylation in a variety of biological processes (i.e., embryonic development, cellular proliferation and differentiation, chromosome stability) has led to a demand for a precise and efficient method to determine the exact DNA methylation status. Bisulfite genomic sequencing is regarded as a gold-standard technology for detection of DNA methylation as it provides a qualitative, quantitative and efficient approach to identify 5-methylcytosine at single base-pair resolution. To optimize the final results of the bisulfite genomic sequencing protocol, numerous modifications have been explored and have significantly improved the sensitivity and accuracy of this procedure. The aim of this methodological report is to give an overview of the bisulfite genomic sequencing protocol, discussing the critical methodological aspects. Since we are interested in studying the methylation status of specific genes involved in T cell development, we applied the bisulfite genomic sequencing to the study of the CD8A T cell co-receptor gene to determine whether the CGIs of this gene were subjected to methylation in different types of tissues. The results show that CD8A gene is differentially methylated depending on the tissue. In conclusion, we described a bisulfite genomic sequencing protocol that can be successfully used for the quantitative analysis of CpG island methylation of specific genes.     

The cholinergic system in the basal forebrain of the Atlantic white‐sided dolphin (Lagenorhynchus acutus)

The basal forebrain (BFB) cholinergic neurotransmitter system is important in a number of brain functions including attention, memory, and the sleep‐wake cycle. The size of this region has been linked to the increase in encephalization of the brain in a number of species. Cetaceans, particularly those belonging to the family Delphinidae, have a relatively large brain compared to its body size and it is expected that the cholinergic BFB in the dolphin would be a prominent feature. However, this has not yet been explored in detail. This study examines and maps the neuroanatomy and cholinergic chemoarchitecture of the BFB in the Atlantic white‐sided dolphin (Lagenorhynchus acutus). As in some other mammals, the BFB in this species is a prominent structure along the medioventral surface of the brain. The parcellation and distribution of cholinergic neural elements of the dolphin BFB was comparable to that observed in other mammals in that it has a medial septal nucleus, a nucleus of the vertical limb of the diagonal band of Broca, a nucleus of the horizontal limb of the diagonal band of Broca, and a nucleus basalis of Meynert. The observed BFB cholinergic system of this dolphin is consistent with evolutionarily conserved and important functions for survival.     

Could n-gram analysis contribute to genomic island determination?

There are two approaches to identifying genomic and pathogenesis islands (GI/PAIs) in bacterial genomes: the compositional and the functional, based on DNA or protein level composition and gene function, respectively. We applied n-gram analysis in addition to other compositional features, combined them by union and intersection and defined two measures for evaluating the results—recall and precision. Using the best criteria (by training on the Escherichia coli O157:H7 EDL933 genome), we predicted GIs for 14 Enterobacteriaceae family members and for 21 randomly selected bacterial genomes. These predictions were compared with results obtained from HGT DB (based on the compositional approach) and PAI DB (based on the combined approach). The results obtained show that intersecting n-grams with other compositional features improves relative precision by up to 10% in case of HGT DB and up to 60% in case of PAI DB. In addition, it was demonstrated that the union of all compositional features results in maximum recall (up to 37%). Thus, the application of n-gram analysis alongside existing or newly developed methods may improve the prediction of GI/PAIs.     

大鼠脊髓胰高血糖素受体的初步实验研究——放射配体结合分析

本实验采用放射配体结合分析研究了脊髓内有无胰高血糖素受体。结果显示,在大鼠脊髓内含有较丰富的~(125)Ⅱ-胰高血糖素的特异性结合位点;且胸、腰段脊髓内特异性位点的结合量无明显差别;比较脊髓前、后部特异性位点的结合量,发现脊髓后半部”~(125)Ⅱ-胰高血糖素的特异性结合量明显较前半部为高;且非标记胰高血糖素可竞争性地与~(125)Ⅱ-胰高血糖素的特异性结合位点结合,其50%抑制剂量(IC_(50))约为0.5 nmol/L。