丝兰属植物提取物降低鸡舍氨气浓度的效果试验

通过在21日龄的肉用仔鸡饲料中添加丝兰属植物提取物(其有效成分为丝兰皂角苷)，研究丝兰属植物提取物对降低鸡舍中氨气浓度和提高肉仔鸡生产性能的效果。试验结果表明，试验组鸡舍内氨气平均浓度为4．75mg／L，对照组鸡舍内氨气平均浓度为13．80mgl／L，试验组比对照组鸡舍内氨气平均浓度降低了9．05mg／L，经t检验，两鸡舍内氨气平均浓度差异显著(P＜0．05)，并且试验组比对照组饲料报酬提高了8.92％。     

波尔山羊与关中奶山羊发情行为对比观察

本文通过对两个引进品种——波尔山羊与关中奶山羊发情行为比较观察,结果发现,波尔山羊发情期三个阶段,发情初期、发情末期,尤其在发情盛期的行为没有关中奶山羊的明显,发情持续时间为26.00±8.98hr,短于关中奶山羊的40.93±8.39hr(P<0.0.1)。公羊试情结合阴道检查是准确鉴定波尔山羊发情的主要方法。本研究还提出在培育、引进或利用波尔山羊品种时,应兼顾繁殖性能的建议。     

不同培养基对杏鲍菇菌丝生长的影响

比较了杏鲍菇一级种和二级种培养基配方 ,试验表明杏鲍菇一级种培养基以配方三最好 ,菌丝干重是配方七 (对照 )的 3 5倍 ,差异极显著 ;杏鲍菇二级种培养基以配方四最好 ,菌丝生长势最强 ,与供试各培养基配方相比较 ,差异均为极显著     

Upregulation of neurokinin A levels by nerve growth factor in the experimental asthmatic guinea pig

AIM: To explore the regulatory mechanism of nerve growth factor (NGF) on neurokinin A in the experimental asthmatic guinea pig. METHODS: Radioimmunoassay was used to determine the alteration of neurokinin A levels in the lower respiratory tract and visceral sensory afferent sites while NGF was absent (inhalation of NGF antibody through nasal cavity) in the asthmatic guinea pig. RESULTS: The contents of neurokinin A in the trachea, bronchus, lung, C₇-T₅ spinal ganglia and the correspondent spinal dorsal horn, nodose ganglia and solitary nucleus area in the experimental asthmatic guinea pig with the absent of NGF in the respiratory tract were much lower than those in the asthmatic and control groups (P＜0.01). CONCLUSION: NGF upregulated the contents of neurokinin A in the lower respiratory tract and visceral sensory sites of the experimental asthmatic guinea pig, and both might be involved in the pathogenesis of asthma.     

Inhibition of K562 cell growth by antisense drug targeting with VEGF mRNA in vitro

AIM: To investigate inhibition of K562 cell growth by antisense drug targeted VEGF mRNA. METHODS: X7, 20-mer antisense sequences were selected, synthesized and modified with phosphorothioate. The drug was transfected into K562 cells in the present of lipofection. Cell growth was assayed by trypan blue dye exclusion assay and MTT. The level of VEGF protein in the media was determined by ELISA. The morphology of apoptotic cells were observed by Giemsa staining, and the propotion of apoptotic cells was detected by flow cytometry. RESULTS: The antisense drug inhibited growth of K562 and downregulated expression of VEGF protein significantly, compared with Scrambed control group and showed dose-dependent relation. Signs of apoptosis of K562 cells were not observed. CONCLUSION: Inhibition of K562 cell proliferation, but not cells apoptosis induction is the mechanism of inhibing growth of K562 cells by antisense drug targeted VEGF mRNA. At same time, VEGF has function of promoting K562 cell proliferation, and VEGF mRNA may be a new target attached by drugs.     

Effect of insulin on the secretion of VEGF and its receptor in serum-free cultured bovine thoracic aortic endothelial cells

AIM: This study was designed to investigate the secretion of VEGF and its receptor (flt-1 or flk-1/KDR) protein by cultured bovine thoracic aortic endothelial cells treated with various insulin concentrations. METHODS: Endothelial cells was isolated from bovine thoracic aorta, and cultured in serum-free medium, then incubated with different insulin concentrations (30 mU/L, 300 mU/L, 3 000 mU/L). The level of VEGF and its receptor (flt-1 or flk-1/KDR) protein were detected by immunohistochemical staining. RESULTS: As compared with no insulin group, the expression of VEGF protein in low insulin concentration (30 mU/L and 300 mU/L) groups were significantly increased (P＜0.01). The expression of VEGF protein in high insulin concentration (3 000 mU/L) group was significantly decreased (P＜0.05). Howerer, no difference of the expression of VEGF receptor (flt-1 or flk-1/KDR) protein among all groups (P＞0.05) was observed. CONCLUSION: Low concentration insulin up-regulates the VEGF protein expression while high concentration insulin down-regulates the VEGF protein expression in bovine thoracic aortic endothelial cells, but insulin had no directly effect on the VEGF receptor (flt-1 or flk-1/KDR) protein expression in bovine thoracic aortic endothelial cells.     

Expression of vascular endothelial growth factor in chronic inflammatory mucosa of lacrimal sac

AIM: To study the expression of vascular endothelial growth factor (VEGF) in inflammatory mucosa of lacrimal sac. METHODS: Immunohistochemical S-P method was used to examine the expression of VEGF in the mocusa from 12 patients with chronic dacryocystitis and 8 volunteers. RESULTS: The positive rates of VEGF expression in different parts of the mocusa were: basal lamina: 44.3%±7.6％; surface epithelium: 16.9%±4.6％; connective tissue: 15.2%±4.9％, all normal mocusa of 8 cases were negative. There was a significant difference between the two groups (P<0.01), a significant difference among each part of the chronic inflammatory mocusa of lacrimal sac. CONCLUSION: VEGF may play an important role in hyperplasia of inflammatory mucosa of lacrimal sac.     

Bone marrow mesenchymal stem cells are induced to differentiate into cardiomyocytes by hepatocyte growth factor in vitro

AIM: To explore a new method of hepatocyte growth factor (HGF) inducing bone marrow mesenchymal stem cells (MSC) to differentiate into cardiomyocytes. METHODS: Bone marrow MSC was cultured with DMEM media (10% fetal calf serum) 4-6 passages, and induced by HGF (10 μg/L) for 30 d. Automatical beating of the differentiated cells was observed daily with transverse microscopy, or under condition of 0.1% isoproterenol or cal-cium-deprived incubation. Specific cardiac myosin in the cells was indentified by immunochemistry. RESULTS: At 14-20 d of differentiation, bone marrow mesenchymal stem cells formed clones, in 10%-50% of which spontaneous beating cell-mass had come to continuously exist. Isoproterenol increased the beating rate and calcium-deprived media inhibited the beating. The cells were identified to be cardiomyocytes by expression of cardiac myosin heavy chain. CONCLUSION: HGF may induce bone marrow mesenchymal stem cells into cardiomyocytes with high efficiency, but the differentiating pathway of stem cells remains to be further studied.     

The role of adrenomedullin in diabetic nephropathy

AIM: To investigate the role of adrenomedullin (AM) in diabetic nephropathy. METHODS: We observed the changes in the expression and secretion of AM, TGF-β₁ in the cultured human mesangial cells under high glucose condition and the contents of the laminin and type IV collagen in the supernatants. The effect of intervention with AM was also observed. RESULTS: High glucose condition resulted in increase in the expression and secretion of AM、 TGF-β₁、 laminin and type IV collagen. AM reversed the influence of high glucose on the cultured human mesangial cells. CONCLUSION: These results showed that high glucose condition is one of stimulating factors of AM and the renal protective action of AM may be associated with suppression of TGF-β₁ and reducing excessive accumulat ion of laminin and type IV collagen.