Six compounds were isolated from the dried leaves and tender branches of Rabdosia ma-crocalyx (Dunn ) Hara. Their structures were identified as excisanin A, excisanin B, rabdol-oxin B, ursolic acid, ?-sitosterol and palmitic acid.

Objective To investigate the chondrogenic feasibility of the human umbilical cord derived mesenchymal stem cells (hUCMSCs)as cartilage tissue engineering seed cells ,type Ⅱ collagen composite glycosaminoglycan scaffold as the cellular carrier and cell‐scaffold complex .Methods The type Ⅱ collagen composite glycosaminoglycan scaffolds was prepared .The pore diameter , porosity and hydrophilia of scaffold materials were observed and measured by electronic microscope .The corresponding histological analysis on the scaffold materials was performed .hUCMSCs of P3 generation were cultured and identified .The hUCMSCs suspen‐sion was inoculated in the type Ⅱ collagen composite glycosaminoglycan scaffold for conducting culture without adding inducer .The samples were taken out after 3 weeks and performed the toluidine blue and safranin O staining ,type Ⅱ collagen immunohistochemi‐cal staining and SEM scanning .Results hUCMSCs of P3 generation highly expressed the mesenchymal cell marker CD29 and CD105 ,while hardly expressed endothelial cells of CD34 and hematopoietic cell markers .The type Ⅱ collagen composite glycosami‐noglycan scaffold presented white porous foam like ,the porosity was (91 .8 ± 2 .17)% ,the average pore diameter was 110‐230 μm , which was homogeneously distributed and had interpenetration .The scaffold showed good hydrophilicity with the water absorption expansion rate of (213 .71 ± 1 .31)% .The scaffold staining of toluidine blue ,safranin O and type Ⅱ collagen was positive .The car‐tilage‐like tissues were observed ,and gradually increased in the surface of cell‐scaffold complex along with culture ,which were posi‐tive in Toluidine blue ,safranin O and type Ⅱ collagen staining ,the electronic microscopic observation displayed that the cells were actively proliferated in the scaffold ,closely adhered with the materials ,the cartilage‐like cells and a large number of peripheral colla‐gen fibers with zigzag connection could be seen .Conclusion Compositing hUCMSCs and type Ⅱ collagen composite glycosamin‐oglycan scaffold could construct tissue‐engineering cartilage in vitro without induction ,which lays a certain experimental foundation for the repair of cartilage damage .

OBJECTIVETo investigate the protection effect of nerve implantation to the neurons after sciatic nerve injury to adult rats.

METHODSThirty male Sprague-Dawley rats weighing 180 - 220 g (8 - 9 weeks of age) were randomly divided into four groups. Group A consisted of normal rats without operation. In group B, the sciatic nerve of rats was transected, with the proximal stump of the sciatic nerve ligated to inhibit nerve regeneration. In group C, a sciatic nerve crushed model was set up. In group D, a sciatic nerve implantation model was established. The rats were sacrificed on postoperative days 7, 14 and 28 respectively. The L(4)-L(6) segments of the spinal cord were harvested. TUNEL technique was used to detect apoptotic motor neurons. HE and Toluidine Blue staining was used for counting motor neurons.

RESULTSThe apoptotic neurons detected on the 28th postoperative day were significantly fewer in the implantation group than in the other groups (P < 0.05). The number of motor neurons was significantly higher in the implantation group than in other two control groups (P < 0.05).

CONCLUSIONSNerve implantation exerts protective effect on neurons after nerve injury.

Animals ; Apoptosis ; Male ; Motor Neurons ; pathology ; Nerve Transfer ; Peripheral Nerve Injuries ; Peripheral Nerves ; pathology ; Rats ; Rats, Sprague-Dawley

Our recent investigation in the protist Trichomonas vaginalis suggested a DNA sequence periodicity with a unit length of 120.9 nt, which represents a sequence signature for nucleosome positioning. We now extended our observation in higher eukaryotes and identified a similar periodicity of 175 nt in length in Caenorhabditis elegans. In the process of defining the sequence compositional characteristics, we found that the 10.5-nt periodicity, the sequence signature of DNA double helix, may not be sufficient for cross-nucleosome positioning but provides essential guiding rails to facilitate positioning. We further dissected nucleosome-protected sequences and identified a strong positive purine (AG) gradient from the 5'-end to the 3'-end, and also learnt that the nucleosome-enriched regions are GC-rich as compared to the nucleosome-free sequences as purine content is positively correlated with GC content. Sequence characterization allowed us to develop a hidden Markov model (HMM) algorithm for decoding nucleosome positioning computationally, and based on a set of training data from the fifth chromosome of C. Elegans, our algorithm predicted 60%-70% of the well-positioned nucleosomes, which is 15%-20% higher than random positioning. We concluded that nucleosomes are not randomly positioned on DNA sequences and yet bind to different genome regions with variable stability, well-positioned nucleosomes leave sequence signatures on DNA, and statistical positioning of nucleosomes across genome can be decoded computationally based on these sequence signatures.