Growth hormone resistance in uremia

Growth retardation is a major complication in children with uremia. Protein restriction, calorie deficit, metabolic acidosis, renal osteodystrophy, and endocrinologic disturbances contribute to the growth failure. The effect of these factors on growth retardation can be attenuated in part by therapy with vitamin D metabolites, adequate nutrition, alkalization, and dialysis. Linear growth in children with uremia is markedly retarded despite normal or increased levels of circulating serum growth hormone. An increased growth hormone level in children with uremia is due to normal growth hormone secretion from the pituitary gland and impaired growth hormone clearance in the kidney. However, the elevated growth hormone level does not lead to a commensurate rise in serum insulin-like growth factor I (IGF-I); the serum IGF-I level is decreased or normal in relation to the degree of renal failure. This discrepancy suggests growth hormone resistance in the liver in uremia. Recent molecular techniques open a new era in studying the gene expression for growth hormone or IGF-I. There is no doubt today that growth hormone treatment has the beneficial effect of growth promotion in children with uremia, which also suggests endogenous growth hormone resistance in target organs or target cells in uremia.     

Joint capsule matrix turnover in a rabbit model of chronic joint contractures: Correlation with human contractures.

To evaluate changes in matrix molecules of the joint capsule, the right knees of 24 skeletally mature female NZW rabbits were immobilized while the contralateral limb served as an unoperated control. The immobilization was discontinued at 8 weeks and the rabbits were divided among four groups (n = 6) based on the number of weeks the right knees were remobilized: 0, 8, 16, or 32. Three rabbits (six knees) that did not have operations provided normal control joint capsules. The mRNA levels for collagen types I, II, and III, and MMP-1 and -13 were significantly increased in the joint capsules of the contracture knees in all groups when compared to normal and contralateral limb joint capsules. In contrast, the mRNA levels for TIMP-1, -2, and -3 were decreased in the joint capsules of the contracture knees in all groups when compared to normal and contralateral limb joint capsules. The mRNA levels for lumican and decorin were increased in the joint capsules of the contracture knees in all groups when compared to normal capsules. Many of the changes observed in this animal model are similar to those observed in human joint capsules from posttraumatic elbow contractures, supporting the value of this rabbit model.     

热应激对血管内皮细胞增殖的影响及其机制初探

目的　探讨热应激条件下对血管内皮细胞增殖的影响 ,进一步从DNA损伤后P5 3mRNA、P2 1mRNA表达改变角度探讨增殖调控的机理。方法　以建立的血管内皮细胞热应激 (4 3℃ ,2小时 )为实验模型 ,应用流式细胞仪观察热应激后血管内皮细胞株ECV30 4的细胞周期变化 ,单细胞凝胶电泳方法观察热应激对血管内皮细胞DNA的损伤 ,RT PCR检测P5 3mRNA、P2 1mRNA表达改变情况。结果　热应激可使血管内皮细胞DNA产生显著损伤 (P <0 .0 5 ) ,继而P5 3mRNA表达增高 ,并促进P2 1mRNA的上调表达 ,最终使细胞产生G1期阻滞。结论　热应激可损伤血管内皮细胞DNA ,并通过P5 3、P2 1通路抑制细胞增殖     

Developmental patterns of intermediate filament gene expression in the normal hamster brain

We have examined the patterns of expression of the major intermediate filament (IF) protein mRNAs during development of the hamster brain. Quantitative northern blotting was used to examine changes in the levels of mRNAs for the low, middle and high molecular weight neurofilament proteins (NF-L, NF-M, NF-H) as well as peripherin, vimentin and glial fibrillary acidic protein (GFAP). Total RNA was isolated from hamster brains at embryonic (E) days 12 and 14 and postnatal (P) days 1, 3, 5, 7, 9, 11, 13, 15, 20, 28 and 60-90 (adult), and probed with specific IF cDNAs. Northern blotting revealed that NF-L and NF-M mRNAs were present at very low levels in embryonic brain and that significant expression of these genes only occurred postnatally when the levels increased dramatically until P28 and then declined again in the adult. Increases in NF-H mRNA levels were somewhat delayed relative to those of NF-L and NF-M. NF-H mRNA was not seen at embryonic stages and was expressed at very low levels prior to P9; after that time the levels increased rapidly until P28 and then declined in the adult. Two of the type III IF genes, peripherin and vimentin, followed a pattern of expression opposite that of the NF genes. Both peripherin and vimentin mRNAs were present in embryonic brain and were expressed at higher levels during early postnatal stages than at later times. The magnitude and rate of reduction in vimentin gene expression in the postnatal interval was much greater than that of peripherin. GFAP mRNA levels were extremely low prior to P9 after which a robust increase occurred, followed by a decline in the adult. We discuss the implication of the dramatic changes in IF isotype expression in brain to the pathways of both neuronal and glial development in vivo.     

The cloning of Na+/Ca2+exchaanger Gene and its expression in brain ischemia

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Efficient RT-PCR on platelet mRNA after long-term storage

We have developed a procedure permitting RT-PCR from mRNA even after a long-term storage (1 year) of platelet samples in ethanol (EtOH-platelets) at −80°C. To validate our method, we have analysed the human platelet alloantigen system (HPA-1) which is coded by β₃ mRNA. We have also demonstrated the efficiency of amplification of part of the coding region for (i) α_IIb subunit mRNA, (ii) α_v subunit mRNA, and (iii) the seven transmembrane domain thrombin receptor mRNA.     

Eosinophil cationic protein is stored in, but not produced by, peripheral blood neutrophils

BACKGROUND: Eosinophil cationic protein (ECP) is an eosinophil-derived protein, which has been shown to be present in circulating neutrophils. OBJECTIVE: To establish whether ECP is produced or internalized by peripheral blood neutrophils. METHODS: This was done using microscopy, flow cytometry, fractionation of cells and RT-PCR techniques. RESULTS: No ECP mRNA was detected after extensive cell purification to eliminate all traces of contaminating eosinophils. Examination of immunostained neutrophils by light, confocal, electron microscopy together with cell fraction experiments, established that ECP is present intracellularly and is mostly associated to cell granules. Uptake studies by flow cytometry and by using both cold and radiolabelled ECP showed that it is internalized by neutrophils and stored in some proportion in their primary granules. Upon stimulation with serum-treated Sephadex particles, the internalized ECP was partially released from cells. CONCLUSION: ECP is not produced but can be internalized by circulating neutrophils, which take it from the environment and partially store it in their primary granules.     

外周炎症时大鼠背根神经节细胞μ-和κ-阿片受体mRNA的表达

目的观察外周炎症时大鼠背根神经节(dorsalrootganglion,DRG)细胞μ-和κ-阿片受体mRNA表达的变化。方法用角叉菜胶(carrageenan,CAR)在大鼠右后足皮下注射产生外周炎症,分别于正常和炎症后6、12、24和72h取右L4~5DRG。用原位杂交的方法观察正常及炎症期间DRG细胞μ-和κ-阿片受体mRNA表达的变化。结果正常大鼠的部分DRG细胞内可见μ-和κ-阿片受体mRNA表达。外周炎症后6h,表达μ-和κ-阿片受体mRNA的DRG细胞的数和μ-和κ-阿片受体mRNA表达量增加,24h表达量最高,72h下降至正常。结论外周炎症能使大鼠DRG细胞μ-和κ-阿片受体mRNA表达增加。提示外周炎症时大鼠DRG细胞μ-和κ-阿片受体合成增加。为阿片类物质应用于外周镇痛提供理论依据。