异落新妇甙的结构研究

从百合科菝葵属植物土茯苓(Smilaxg labra Roxb.)根茎的乙醇提取物中分得一个新的天然化合物(I),命名为异落新妇甙(isoastilbin)。根据元素分析,UV,IR,¹H-NMR,¹³C-NMR,2DNMR及FAB-MS,确定化合物I的结构为5,7,3',5'-四羟基二氢黄酮醇-3-O-α-L-鼠李糖甙。     

Interaction of B and T lymphocyte subsets with high endothelial venules in the rat: binding in vitro does not reflect homing in vivo

Lymphocytes continuously migrate through the body, and their efficient extravasation from the blood via high endothelial venules (HEV) is essential for initiating an appropriate immune response. Most investigations have focused on the lymphocyte/HEV interaction in vitro. However, to what extent such systems reflect the situation in vivo is not known. It is also unclear whether lymphocyte subsets immigrate into the HEV in proportion to their presence in the blood, and whether import capacity is limited by the HEV. When rat mesenteric lymph node lymphocytes were incubated in vitro on cryostat sections, the well-known preferential binding of B lymphocytes to HEV of Peyer's patches (PP) and T cells to HEV of axillary lymph nodes (axLN) was observed (axLN vs. PP: B lymphocytes 21.2 ± 5.0% vs. 40.6 ± 11.0%, T lymphocytes 84.6 ± 6.3% vs. 56.5 ± 12.9%). However, when labeled mesenteric lymph node lymphocytes were injected and their location within the HEV was analyzed 15 min later, no preferential interaction was seen. After injection of labeled thoracic duct lymphocytes, the percentage of labeled cells among B and T lymphocytes in the blood was significantly different (4.4 ± 0.9% vs. 8.9 ± 3.6%), whereas that in HEV of axLN (19.0 ± 6.4% vs. 16.6 ± 6.0%) and PP (30.6 ± 6.1% vs. 33.9 ± 4.4%) was comparable. Although the number of injected lymphocytes was similar in magnitude to the total blood lymphocyte pool, after injection there was no increase in lymphocyte numbers in the HEV. Thus, the adhesion assay in vitro does not completely reflect immigration into HEV in vivo. In addition, our data suggest that both the availability of lymphocyte subsets in small venules and the immigration rate into HEV are actively regulated in vivo.     

Autotransplantation of splenic tissue

Autotransplantation of splenic fragments has already been carried out in humans. The optimal size of the particles and amount of tissue required for this procedure has yet to be found. In normal young pigs and miniature piglets, autologous splenic tissue was transplanted into the greater omentum. The regenerated splenic mass, splenic blood flow, and histology were studied six months later. Implanting small splenic particles produced comparable results to implanting thin slices of splenic tissue. The mass of regenerated splenic tissue was only 3.1 g after implanting the whole spleen and 4.5 g after transplanting half of the spleen, which means 5.3% and 7.8% respectively of the weight of control spleens. The blood flow per gram in the regenerated splenic tissue was much lower than in the normal spleen. The blood flow in the whole of the splenic tissue is important for the clearance function of the spleen. Six months after transplanting the whole or half of the spleen, the blood flow to the regenerated splenic tissue was only 1% of that in the control minipigs. When half of the spleen was left in situ, as a model for a partial splenectomy, and the other half transplanted, the regenerated mass was only 3.4% of all splenic tissue and the blood flow 1.5% of the total splenic blood flow. In this model the regenerated splenic mass was independent of the size of the implants and the mass of implanted tissue. The extremely low blood flow indicates an inadequate clearance function and thus the protective function would probably be negligible.     

Effects of microbial stimulation on the number, size and activity of bronchus-associated lymphoid tissue (BALT) structures in the pig.

The development of bronchus-associated lymphoid tissue (BALT) was investigated in the pig, which is a species in which BALT is not found constantly. Different routes of contact with a specifically lung-pathogen bacterium Actinobacillus (Haemophilus) pleuropneumoniae were tested. Pigs, selected by bacteriological screening methods and the number of granulocytes in the bronchoalveolar lavage (BAL), were infected by aerosol. They were compared to previously enterally immunized pigs using active and inactivated bacteria. The development of BALT after the infection was compared to that in pigs with a single enteral, or no, contact with the bacterium. BALT was less frequent in these groups than in the infected pigs. Previously immunized pigs developed the highest number and the largest BALT with the most prominent morphological signs of activation. Immunization with living or inactivated bacteria did not cause histological differences. BALT was preferentially located around bronchioli and small bronchi. Additional BALT predominantly occurred in the walls of larger bronchi. Definite compartments of T and B lymphocytes were not found in immunohistological studies of BALT. It was concluded that the development of BALT can be induced by different modes of microbial stimulation.     

一些保肝药物对原代培养大鼠肝细胞糖原合成功能的影响

本文参照PO Seglen的方法并加以修改,建立了原代培养大鼠肝细胞糖原合成功能的测定体系。观察到联苯双酯既能使正常肝细胞合成糖原增加88%,又能保护肝细胞完全拮抗四氯化碳对其功能的损伤;银耳多糖能使四氯化碳对肝细胞糖原合成功能的损伤减轻57%;去甲斑蝥素10μg/ml能增加肝细胞糖原合成,浓度增加到100μg/ml时,此作用减弱,1000μg/ml则明显抑制糖原的合成,而且在10～100μg/ml浓度时,即能加强四氯化碳的损伤作用;100μg/ml CL₁₅₀₀和熊果酸二钠单独应用可增加肝细胞糖原合成,但与四氯化碳同时应用,反而加重对糖原合成的抑制作用。     

Gross anatomy: An outdated subject or an essential part of a modern medical curriculum? Results of a questionnaire circulated to final-year medical students

Final-year undergraduate medical students were given a questionnaire on the gross anatomy curriculum they had experienced in their first year at medical school 5 years earlier. They were asked to evaluate the relevance of the dissection course, lectures and seminars in gross anatomy for clinical courses, clerkships, and everyday practical work on the ward. About two-thirds of the students found the time spent on 10 different regions in anatomy to be adequate, and a considerable number of students would have liked even more details. The vast majority expressed a wish to repeat topographical anatomy during their clinical teaching. Furthermore, ～75% of the students showed interest in short, specialized dissection courses during the clinical curriculum. Medical students just before graduation ranked gross anatomy with the dissection course and integrated clinical topics as a keystone for their clinical courses. The results of such surveys should be taken into consideration when discussing modification to teaching gross anatomy or arguing about a balanced dissection course. © 1993 Wiley-Liss, Inc.     

Numbers and phenotype of lymphocytes emigrating from sheep bone marrow after in situ labelling with fluorescein isothiocyanate

In normal young lambs the bone marrow was selectively labelled with fluorescein isothiocyanate by a temporary perfusion of one hind-leg. One day later, the incidence of bone marrow emigrants in different lymph nodes, spleen, Peyer's patches, thymus, non-perfused bone marrow and blood was determined. The emigrants were also phenotyped by the use of monoclonal antibodies and classified into monocytes or lymphocyte subsets. Large numbers of lymphocytes left the bone marrow of the perfused leg during 1 day. Considerable numbers of cells migrated to other bone marrow compartments. Varying numbers of mononuclear emigrants were found in peripheral lymphoid organs, with labelling indices ranging from 1.06% in the blood to 0.004% in the thymus. In the spleen, comparable numbers of B- and T-lymphocyte emigrants from the bone marrow were found, whereas in the blood, lymph nodes and jejunal Peyer's patches many more emigrants were T lymphocytes than B lymphocytes. In the prescapular lymph nodes, for instance, 90.4% of emigrants were T cells but only 9.6% were B cells. Based on the large numbers of lymphocytes emigrating from the bone marrow, their phenotypes and their entry into other bone marrow compartments, it it can be concluded that the bone marrow of young lambs is an integral part of the migratory route of lymphocytes.     

Postnatal development and lymphocyte production of jejunal and ileal Peyer's patches in normal and gnotobiotic pigs.

The development of the number, size, structure and proliferative capacity of Peyer's patches (PP) in the jejunum and ileum has been studied during the early postnatal period of conventional and germ-free pigs. A mean of 15 discrete PP in the jejunum and upper ileum (jejPP) were counted at birth, and the number increased only gradually. A continuous PP is located in the terminal ileum (ileal PP). The length of both jejPP and ileal PP increased with age due to the increase in follicle size and in the number of follicles in the ileal PP. In older pigs, only the ileal PP regressed to small scattered follicles. In germ-free piglets at 39 and 59 days of age, longer PP were found than in normal new-born piglets, but they were significantly shorter than in age-matched controls. Lymphocyte production was studied by the metaphase-arrest technique using vincristine. Lymphocyte production in follicles increased dramatically with age, while in other compartments, such as the inter-follicular and dome area, a low age-independent production of lymphocytes was found. There were no differences in lymphocytopoiesis between jejPP and ileal PP. The present data show major differences in the development, structure and function of PP in pigs in comparison to other species. These species-specific aspects are important for future studies on the immunological function of PP.     

Secretion of vascular endothelial growth factor/vascular permeability factor from human luteinized granulosa cells is human chorionic gonadotrophin dependent

Vascularization is a prominent event during corpus luteum formation, providing low density lipoproteins for steroid biosynthesis and enabling transport of secreted steroids. The process of vascularization is controlled by specific regulators. Vascular endothelial growth factor (VEGF), otherwise named vascular permeability factor (VPF), induces endothelial cell proliferation as well as angiogenesis in vivo and increases capillary permeability. Here we report the expression of VEGF/VPF mRNA by cultured human luteinized granulosa cells (GC) for at least 10 days. Without HCG VEGF/VPF expression declined after day 4 and by day 10 was reduced to approximately 30% of the value at day 4. However, after culture in the presence of 1 U/ml human chorionic gonadotrophin (HCG), expression of VEGF/VPF mRNA by GC was four times greater than control experiments by day 10, and increased 100% from day 4 to day 10. Simultaneously, HCG supplementation increased VEGF/VPF secretion by GC. Medium VEGF/VPF on day 3 was 13 pM without and 11 pM with HCG. Medium VEGF/VPF on day 10 was 6 pM without HCG and 29 pM with HCG. These results suggest that vascularization of the corpus luteum is induced by HCG-mediated effects of VEGF/VPF.