Community structure and regeneration types of Betula dahurica forest in Badaling forest center of Beijing

Using plant community analysis methods, we analyzed the floristic characteristics, species composition, community structure, population structure, and spatial distribution patterns of a Betula dahurica forest on the ＂1238＂ mountain of Badaling in Beijing, China. The results show that： 1） There are 33 plant species in the B. dahurica community, including 18 woody plant species. The B. dahurica forest is a monodominant community with 75.9% dominance. 2） Based on diameter at breast height （DBH） size class distribution, the population structure of B. dahurica and Acer mono--two heliophyllous and pioneer tree species-is cascade-type, with both in an increasing stage. The population structure of Ella mandshurica and T. mongolica, two shade-tolerant tree species, is inverse-J type, and they have more young seedling individuals and regenerate more stably. They are associated species of the pioneer tree species. The population structure of Quercus mongolica, as the associated species of climax species in the community, is sporadic, and its regeneration is fluctuating and random. Fraxinus rhynchophylla is a shade-tolerant tree species which has a unibar population structure and climax characteristics of pioneer tree species. The relative frequency of young seedlings reached 0.4. 3） The dominant species B. dahurica is still in an increasing stage, and the regeneration of other species is steady or partly influences the community, putting the community in the pioneer species stage. From the population structure and distribution frequency ofF. rhynchophylla, the B. dahurica forest will approach to a climax state in the future.

Significance of regenerating islet-derived type Ⅳ gene expression in gastroenterological cancers

The regenerating islet-derived members （Reg）, a group of small secretory proteins, which are involved in cell proliferation or differentiation in digestive organs, are upregulated in several gastrointestinal cancers, functioning as trophic or antiapoptotic factors. Regenerat- ing islet-derived type Ⅳ （RegⅣ）, a member of the Reg gene family, has been reported to be overexpressed in gastroenterological cancers. RegIV overexpression in tumor cells has been associated with carcinogen- esis, cell growth, survival and resistance to apoptosis. Cancer tissue expressing RegIV is generally associated with more malignant characteristics than that with- out such expression, and RegⅣ is considered a novel prognostic factor as well as diagnostic marker in some gastroenterological cancers. We previously investigated the expression levels of RegⅣ mRNA of 202 surgical colorectal cancer specimens with quantitative real-time reverse-transcriptase polymerase chain reaction and reported that a higher level of RegⅣ gene expression was a significant independent predictor of colorec- tal cancer. The biologic functions of RegⅣ protein in cancer tissue, associated with carcinogenesis, anti- apoptosis and invasiveness, are being elucidated by molecular investigations using transfection techniques or neutralizing antibodies of RegIV, and the feasibility of antibody therapy targeting RegIV is being assessed. These studies may lead to novel therapeutic strate- gies for gastroenterological cancers expressing RegⅣ. This review article summarizes the current information related to biological functions as well as clinical impor- tance of RegⅣ gene to clarify the significance of Reg~ expression in gastroenterological cancers.

Verapamil inhibits scar formation after peripheral nerve repair in vivo

The calcium channel blocker,verapamil,has been shown to reduce scar formation by inhibiting fibroblast adhesion and proliferation in vitro.It was not clear whether topical application of verapamil after surgical repair of the nerve in vivo could inhibit the formation of excessive scar tissue.In this study,the right sciatic nerve of adult Sprague-Dawley rats was transected and sutured with No.10-0 suture.The stoma was wrapped with gelfoam soaked with verapamil solution for 4 weeks.Compared with the control group（stoma wrapped with gelfoam soaked with physiological saline）,the verapamil application inhibited the secretion of extracellular matrix from fibroblasts in vivo,suppressed type I and III collagen secretion and increased the total number of axons and the number of myelinated axons.These findings suggest that verapamil could reduce the formation of scar tissue and promote axon growth after peripheral nerve repair.