GKK1032B from endophytic Penicillium citrinum induces the apoptosis of human osteosarcoma MG63 cells through caspase pathway activation / 中国天然药物

Chemical investigation of the culture extract of an endophytic Penicillium citrinum from Dendrobium officinale, afforded nine citrinin derivatives (1-9) and one peptide-polyketide hybrid GKK1032B (10). The structures of these compounds were determined by spectroscopic methods. The absolute configurations of 1 and 2 were determined for the first time by calculation of electronic circular dichroism (ECD) data. Among them, GKK1032B (10) showed significant cytotoxicity against human osteosarcoma cell line MG63 with an IC50 value of 3.49 μmol·L-1, and a primary mechanistic study revealed that it induced the apoptosis of MG63 cellsvia caspase pathway activation.

Practice and exploration of the tuition-free medical students' in rural areas of Sichuan province / 中国卫生政策研究

Objective:This paper summarizes the practical problems encountered in the implementation of the tuition-free medical students' policyin rural areas of Sichuan Province, and provides a reference for the implementation of this policy across the province. Methods :Semi-structured interviews were conducted with the principals of the orientation management policies of the health administrative departments and county level and primary health care in-stitutionsin Sichuan, and the focus group interviews were used to understand the dynamics of directed students. Results :The survey results showed that there were limited channels for students to understand the policy ; students' barren understanding of the work of grass-roots doctors ; credit and integrity files played a relatively low role in retaining medical talent students;the willingness of orientation students is higher, but there is a contradiction between applying for graduate students and retaining grassroots in rural areas ; and the relevant departments lacked a rational and efficient management mode for students. Conclusions :In order to ameliorate the construction of rural health human resources,policy administrators should place their emphasis on cultivating the sense of honor and responsibility in the rural-oriented tuition-free medical students'policy, improve the reward and punishment mechanism in policies, optimize the management and assessment process, and promote the orientation of the work among the various policy-participating departments in a more harmonious and orderly manner.

Refined mapping of the loss of heterozygosity on chromosome 1q21 in gastric carcinoma / 南方医科大学学报

<p><b>OBJECTIVE</b>To obtain allelic loss mapping and define the minimal lost region on chromosome 1q21 in gastric carcinomas, and explore role of 1q21 loss of heterozygosity (LOH) in the development and progression of gastric carcinogenesis.</p><p><b>METHODS</b>Using 7 high-density microsatellite markers and PCR method, lq21 LOH was analyzed in 30 paired specimens of fresh gastric carcinoma, and the relation between 1q21 LOH and the clinicopathological features of the malignancy was tested.</p><p><b>RESULTS</b>The LOH frequency on chromosome 1q21 from these gastric carcinoma tissues reached 60% (18/30). The LOH frequencies of the microsatellite markers D1S514, D1S2696, D1S498, D1S305, D1S2624, D1S2635 and D1S2702 were 13.3%, 10%, 20%, 23.3%, 33.3%, 40% and 23.3%, respectively. The minimal lost region on 1q21 LOH in the gastric carcinoma tissues was located in the region between D1S2624 and D1S2707, in the vicinity of D1S2635. No significant relations of 1q21 LOH to the patients' age, gender, location of the primary foci, clinical staging, or the tumor differentiation were noted (P>0.05), but 1q21 LOH was correlated to lymph node metastases of the malignancy (P<0.05).</p><p><b>CONCLUSION</b>Higher frequency of 1q21 LOH occurs in gastric carcinoma cells, suggesting the presence of potential tumor suppressor genes closely associated with gastric carcinogenesis near the region of D1S2635.</p>

Construction of hu-PBL/SCID chimeras and development of EBV-related lymphomas / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To construct hu-PBL/SCID chimeras and to investigate the development of lymphoma and oncogenicity of the Epstein-Barr virus (EBV).</p><p><b>METHODS</b>Human peripheral blood lymphocytes (PBLs) were isolated from healthy adult donors and transplanted intraperitoneally into severe combined immunodeficient (SCID) mice. Mice with hu-PBL engraftment from healthy EBV seronegative donors were injected intraperitoneally with EBV-containing supernatant from suspension culture of B95-8 cell line (active infection), whereas mice receiving lymphocytes from healthy EBV seropositive donors were not re-infected with B95-8 derived EBV (latent infection). Pathological examination and molecular analysis were performed on experimental animals and induced neoplasms.</p><p><b>RESULTS</b>In the early stage of this experiment, 12 mice died of acute graft-versus-host disease, mortality was 34.3% (12/35 mice) with an average life span of 17.5 days. In 19 survival hu-PBL/SCID chimeric recipients from 12 healthy donors, tumor incidence was 84.2% (16/19 mice). The average survival time of tumor-bearing mice was 65.5 days. EBV-related neoplasms in SCID mice were nodular tumors with aggressive and fatal features. Histological morphology of tumors exhibited diffuse large cell lymphomas. Immunohistochemistry revealed that LCA (CD45) and L26 (CD20) were positive, but both PS1 (CD3) and UCHL-1 (CD45RO) were negative, and EBV products ZEBRA, LMP1, and EBNA2 were expressed in a small number of tumor cells. EB virus particles were seen in the nuclei of some tumor cells by electron microscopy, and EBV DNA could be amplified in the tumor tissues by PCR. In situ hybridization indicated that the nuclei of tumor cells contained human-specific Alu sequence.</p><p><b>CONCLUSIONS</b>EBV-induced tumors were human B-cell malignant lymphomas. We obtained direct causative evidence dealing with EBV-associated tumor deriving from normal human cells.</p>

Study of the relative factors of the biological behavior of pleomorphic adenoma in parotid / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To study the growth way of parotid pleomorphic adenoma and the relative factors.</p><p><b>METHODS</b>The histological slides of 97 cases of the primary parotid pleomorphic adenoma were examined for the state of intra-capsule infiltration and extra-infiltration. The relative relationships between the infiltration state and the histological type, relative amount of various components, size and course of the tumor were analysed to investigate the growth way and relative factors.</p><p><b>RESULTS</b>1. There were more chances to develop infiltration of tumor in which the major content was epithelium. The tumor was severer with the increasing of epithelium, and decreasing of mucous content and elongation of course of the disease. 2. The limitation of the extra-envelop infiltration and budding was 0.085 - 0.210 mm, so, the boundary of partial parotidectomy should be away from the 1 cm envelop.</p><p><b>CONCLUSION</b>The growth way of parotid pleomorphic adenoma is related to the histological types and characters, relative amount of various components and the course of the tumor.</p>

Heterotopic chondrogenesis of human adipose tissue-derived stromal cells loading on alginate gel / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To isolate and chondro-inductive culture of human adipose tissue-derived stromal cells and to study their heterotopic chondrogenesis by loading them on alginate gel.</p><p><b>METHODS</b>Liposuction human adipose tissues were minced and digested with collagenase type I. The obtained stromal cells were primarily cultured in BGJb medium for ten days. Secondary harvested cells were cultured in DMEM-F12 medium supplemented with 10%FBS, 6.25 mg/L insulin, 10 mg/L TGF-beta1, 50 mg/L of freshly prepared L-ascorbate for 14 days. After in vitro assay of chondrogenic phenotypes, the cells at density of 10(10)/L were mixed with 1.2% alginate sodium and 102 mmol/L CaCl(2). The cross-linking cell-alginate gel were injected into four BALB/C athymic mice subcutaneously (1 ml for each mouse). Meanwhile, the auto-controls were set by injecting equal dose of simple alginate gel and pure cells in two opposite buttocks of the same mouse subcutaneously. Two mice were sacrificed at fourth and eighth week postoperatively and all samples were removed, fixed, embedded in paraffin and cut into sections of 5 micro m thick. HE staining, Alcian blue and modified Masson's trichrome staining were employed to observe chondrogenesis histologically.</p><p><b>RESULTS</b>Alcian blue and immunocytochemical staining revealed chondroitin sulfate and collagen II in cell matrix after having been chondro-inductive cultured for 14 days. At intervals of fourth and eighth week, heterotopic chondrogenesis is (cartilage formed) within cell-alginate injected sites were found in all mice but negatively in auto-controls. Histologically the hypertrophic chondrocytes were among cartilage matrix in different staining. All alginate gel and solitory cells absorbed within two to three weeks postoperatively in auto-controls.</p><p><b>CONCLUSION</b>It seems that stromal cells derived from human adipose tissue presents a potential for chondrogenic differentiation.</p>