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91.
Using the whole-cell configuration of the patch clamp technique, calcium-activated potassium currents (IK,Ca) were investigated in ramified murine brain macrophages. In order to induce IK,Ca the intracellular concentration of nominal free Ca2+ was adjusted to 1μM. The Ca2+-activated K+ current of brain macrophages did not show any voltage dependence at test potentials between –120 and +30mV. A tenfold change
in extracellular K+ concentration shifted the reversal potential of IK,Ca by 51mV. The bee venom toxin apamin applied at concentrations of up to 1μM did not affect IK,Ca. Ca2+-activated K+ currents of ramified brain macrophages were highly sensitive to extracellularly applied charybdotoxin (CTX). The half-maximal
effective concentration of CTX was calculated to be 4.3nM. In contrast to CTX, the scorpion toxin kaliotoxin did not inhibit
IK,Ca at concentrations between 1 and 50nM. Tetraethylammonium (TEA) blocked 8.0% of IK,Ca at a concentration of 1mM, whereas 31.4% of current was blocked by 10mM TEA. Several inorganic polyvalent cations were tested
at a concentration of 2mM for their ability to block IK,Ca. La3+ reduced IK,Ca by 72.8%, whereas Cd2+ decreased IK,Ca by 17.4%; in contrast, Ni2+ did not have any effect on IK,Ca. Ba2+ applied at a concentration of 1mM reduced IK,Ca voltage-dependently at hyperpolarizing potentials.
Received: 17 January / Accepted: 5 May 1997 相似文献
92.
近3年来,用制备的胎骨充填良性骨肿瘤及病样病变术后骨缺损,经观察10例效果良好。胎骨因其自身组织学和生理学特点,具有抗原性小、诱导成骨活性高,利于“爬行各代”等优点。而且来源丰富、采制简单、储存容易、费用低度,是一种良好的植骨材料,特别适于儿童及年老体弱患者自身取骨困难的骨缺损植骨需要。但其为异体骨,有一定免疫原性,抗支撑强度略差,应注意严格无菌操作、消除免疫原性、配合使用内、外固定等措施。 相似文献
93.
18例慢性肾衰继发性甲旁亢病人发现有锁骨骨吸收。发病部位包括锁骨内端、外端、外1/3下缘及内段下缘4个部位。其中锁骨内、外端骨吸收属软骨下骨吸收,内、外段下缘骨吸收属韧带下骨吸收。作者对锁骨骨吸收的X线表现及发病机制作了讨论。认为锁骨骨吸收是继发性甲旁亢的重要X线征象,对诊断肾性骨病具有重要的意义。 相似文献
94.
Alpha2-HS glycoprotein phenotypes and quantitative hormone and bone measures in postmenopausal women
June E. Eichner Christopher A. Friedrich Jane A. Cauley Mohammad I. Kamboh James P. Gutai Lewis H. Kuller Robert E. Ferrell 《Calcified tissue international》1990,47(6):345-349
Summary It has been suggested that inherited traits play a role in the development of osteoporosis by providing a background for the
modulation of gene expression. In this study, we examine the influence of the different alleles of alpha2-HS glycoprotein (AHSG), a protein of the bone matrix, on quantitative estrogens, estrone and estradiol, and bone measures,
bone area and density. Estrogens provide a protective effect against fractures in older women and were thus included in the
analyses. Isoelectric focusing of AHSG from sera followed by immunoblotting was used to type 163 white post-menopausal women
participating in a clinical trial of the effects of walking on bone loss. Plasma hormones were measured by a combination of
extraction, column chromatography, and radioimmunoassay; bone measures on the dominant radius were determined with computerized
tomography. Analysis of variance was done on estrogen and bone measures after controlling for the effects of age and body
mass index. The two major alleles of AHSG result in three phenotypes, designated AHSG 1-1, AHSG 2-1, and AHSG 2-2. The AHSG
1-1 homozygote showed a decreased concentration of estradiol, the AHSG 2-2 homozygote showed an increased concentration, and
the AHSG 2-1 heterozygote was intermediate (P=0.001). Estrone demonstrated a similar pattern in residual analysis although it did not reach statistical significance. 相似文献
95.
96.
97.
为探讨无名异接骨冲剂加速骨折愈合的作用机理,选用55只新西兰大白兔,随机选择5只作为正常组;另50只在无菌条件下造成双桡骨标准骨折模型。将50只骨折兔随机平均分为实验组和对照组,实验组用无名异接骨冲剂每天4g/kg溶于20ml蒸馏水中分早晚两次灌胃;对照组用20ml蒸馏水灌胃。于骨折后第1,2,3,4及5周用断颈法每次每组处死5只兔,取骨痂进行抗骨形态发生蛋白(BMP)单克隆抗体免疫组化染色,并用CMIAS型图像分析仪对BMP含量进行定量分析。结果发现:实验组骨折局部BMP含量明显高于正常组(P<0.01);第1,2周实验组明显高于对照组(P<0.01);实验组BMP高峰出现在第2周,而对照组出现在第3周。认为,无名异接骨冲剂能促进成骨细胞合成BMP,使BMP峰值提前,从而加速骨折愈合。 相似文献
98.
Masatoshi Chiba Takashi Shigihara Seishi Echigo Teiichi Teshima 《Journal of bone and mineral metabolism》1990,8(3):24-29
Summary In this study, we examined histologically the effect of a bone morphogenetic protein (BMP) derived from bovine tooth on the
periosteum. Supraperiosteal injection of crude BMP into femurs of Wistar rats (28 day old) resulted in periosteal cell proliferation
with subsequent bone and cartilage formation. Moreover, proliferating periosteal cells migrated into injected BMP, and formed
both cartilage and bone. These observations show that exogenous BMP stimulates mesenchymal cells of the periosteum to proliferate
and differentiate into osteoblasts, and therefore BMP may be one of factors which are involved in differentiation of osteoblasts
in the periosteum. 相似文献
99.
Summary A study of the association between the rate of proliferation of marrow fibroblast-like stromal cells (in vitro) and the rate of endosteal bone mineralization (EsMR) (in vivo) was undertaken in an osteopenic rat model. We report than 200 g male rats treated with cortisone acetate (5 mg/day for 7
days) exhibit decreases in marrow fibroblast colony-forming units (FCFU) and tetracycline-based measurements of EsMR at the
level of the femoral midshaft. In cortisone-treated rats recovering for 1–3 weeks, the FCFU census and EsMR normalized during
the first posttreatment week, remained at control levels after 2–3 weeks, and exhibited a relapse in the third week which
signified only partial recovery. These changes were unrelated to patterns of body weight gain. The data indicate that the
FCFU census can serve to index endosteal osteoblast vigor. 相似文献
100.
Summary It is generally accepted that osteoclasts are responsible for the breakdown and removal of bone matrix constituents. However,
very little is known about the fate of osteocytes during bone resorption. In the present study we have examined sites of bone
destruction in calvaria of young rats aged 4–9 days in the hope of obtaining information on the fate of osteocytes. Decalcified
glutaraldehyde-formaldehyde-fixed specimens were prepared for ultrathin section electron microscopy. When sequentially arranged,
the images obtained suggest that osteoclasts engulf and destroy osteocytes during bone degradation. We propose that the following
sequence of events takes place when a lacuna is opened up by an osteoclast: (1) When the osteoclast comes in contact with
an osteocyte, the villi of the ruffled border become flat and broad. (2) Long osteoclastic extensions surround the osteocyte.
(3) The osteocyte is subsequently internalized with apparent degradation. 相似文献