树鼩血栓性脑缺血中心区及半暗区神经元PAF受体结合特性的研究

目的：观察血栓性局部脑缺血过程中缺血中心区及半暗区血小板活化因子（PAF）受体的消长变化,探讨PAF在脑缺血中心区及半暗区神经元继发性脑损伤中的分子机制。方法：建立光化学诱导树鼩血栓性局部脑缺血模型并提取树鼩脑细胞膜蛋白,用[³H]-PAF放射配体结合试验检测中枢神经细胞膜不同特性的PAF结合位点（受体）。结果：树鼩脑细胞膜上存在两种亲和性不同的PAF受体,即高亲和性和低亲和性受体,其亲和力（kD）分别为(3.61±0.72) nmol/L（kD₁）和17.04±2.41) nmol/L（kD₂）相应的最大结合容量（B_max）分别为(1 457.94±168.01) pmol/g蛋白和(5 017.40±742.16) pmol/g蛋白。脑缺血4、24及72 h中心区、半暗区及对侧区高、低亲和性受体的kD值、B_max值均显著低于假手术组（P<0.01）,中心区及半暗区尤为明显,其中以缺血后24 h的变化最为显著。结论：PAF受体在介导缺血性脑损伤过程中起着重要作用,缺血中心区及半暗区机能代谢的不同与PAF受体亲和特性及最大结合容量改变不同有关,亦是PAF介导继发性脑损伤的重要分子基础。     

树血栓性脑缺血中心区及半暗区神经元PAF受体结合特性的研究

目的 :观察血栓性局部脑缺血过程中缺血中心区及半暗区血小板活化因子 (PAF)受体的消长变化 ,探讨PAF在脑缺血中心区及半暗区神经元继发性脑损伤中的分子机制。方法 :建立光化学诱导树鼠句血栓性局部脑缺血模型并提取树鼠句脑细胞膜蛋白 ,用 [3H]-PAF放射配体结合试验检测中枢神经细胞膜不同特性的PAF结合位点 (受体 )。结果 :树鼠句脑细胞膜上存在两种亲和性不同的PAF受体 ,即高亲和性和低亲和性受体 ,其亲和力 (kD)分别为 ( 3 61± 0 72 )nmol/L(kD1)和 ( 17 0 4± 2 4 1)nmol/L(kD2 ) ,相应的最大结合容量 (Bmax)分别为 ( 14 5 7 94± 168 0 1)pmol/g蛋白和 ( 5 0 17 4 0± 74 2 16)pmol/g蛋白。脑缺血 4、2 4h及 72h中心区、半暗区及对侧区高、低亲和性受体的kD值、Bmax值均显著低于假手术组 (P <0 0 1) ,中心区及半暗区尤为明显 ,其中以缺血后 2 4h的变化最为显著。结论 :PAF受体在介导缺血性脑损伤过程中起着重要作用 ,缺血中心区及半暗区机能代谢的不同与PAF受体亲和特性及最大结合容量改变不同有关 ,亦是PAF介导继发性脑损伤的重要分子基础     

树鼩血栓性脑缺血时单胺氧化酶活性的变化及银杏内酯B作用机制探讨

目的 :揭示血栓性脑缺血时缺血区和血清单胺氧化酶 (MAO)活性变化及对血小板活化因子 (PAF)受体拮抗剂银杏内酯B(GB)作用机理的探讨。方法 :建立光化学诱导树鼠句血栓性脑缺血模型 ,用酶比色法测量缺血后4、2 4及 72h中心区、半暗区、对侧区及血清的MAO活性 ,并用双缩脲法测定上述各区的蛋白含量。结果 :脑缺血后不同时间缺血中心区MAO活性显著低于假手术组 [(15 4 1± 1 6 3)× 10 3 U/g蛋白 ]或对侧区 [(15 4 7± 1 6 8)× 10 3 U/g蛋白 ],以 72h最为明显 [(2 19± 1 96 )× 10 3 U/g蛋白 ,P <0 0 1];此时缺血半暗区和血清MAO活性 [分别为 (2 5 30± 2 0 1)× 10 3 U/g蛋白和 (2 10 0 4± 2 6 6 7)× 10 3 U/L]明显高于假手术组 (P <0 0 1)。光化学反应后 6h舌下静脉一次注射PAF受体拮抗剂GB(5mg·kg-1)后 2 4h时 ,半暗区MAO活性明显低于缺血组 ,而中心区则高于缺血组 (P <0 0 1)。MAO活性变化与相应区域蛋白含量改变一致 (r=0 81,P <0 0 5 )。结论 :脑缺血后中心区、半暗区MAO活性改变是相应区域单胺类递质消长变化的主要原因 ,MAO活性变化与神经元蛋白质合成能力的改变有关 ;GB的脑保护作用与其拮抗PAF受体和调节MAO活性而促进递质平衡有关。     

树鼩血栓性脑缺血时单胺氧化酶活性的变化及银杏内酯B作用机制探讨

目的:揭示血栓性脑缺血时缺血区和血清单胺氧化酶(MAO)活性变化及对血小板活化因子(PAF)受体拮抗剂银杏内酯B(GB)作用机理的探讨。方法:建立光化学诱导树鼠句血栓性脑缺血模型,用酶比色法测量缺血后4、24及72h中心区、半暗区、对侧区及血清的MAO活性,并用双缩脲法测定上述各区的蛋白含量。结果:脑缺血后不同时间缺血中心区MAO活性显著低于假手术组或对侧区,以72h最为明显;此时缺血半暗区和血清MAO活性明显高于假手术组(P＜0.01)。光化学反应后6h舌下静脉一次注射PAF受体拮抗剂GB(5mg·kg^-1)后24h时,半暗区MAO活性明显低于缺血组,而中心区则高于缺血组(P＜0.01)。MAO活性变化与相应区域蛋白含量改变一致(r=0.81,P＜0.05)。结论:脑缺血后中心区、半暗区MAO活性改变是相应区域单胺类递质消长变化的主要原因,MAO活性变化与神经元蛋白质合成能力的改变有关;GB的脑保护作用与其拮抗PAF受体和调节MAO活性而促进递质平衡有关。     

输精管结扎对兔前列腺睾酮受体的影响

14只日本大耳白雄兔,7只为假手术组(SOG),7只为输精管结扎组(VG)。16个月后,检测前列腺睾酮受体和血清睾酮的变化。结果是VG和SOG胞液受体的kd值分别为10.21nM和3.42nM,最大结合容量分别为33.68fmol/mgpro.和10.42fmol/mg pro;胞核受体的kd值分别为9.36nM和4.81nM,最大结合容量分别为440.90fmol/mg DNA和203.66fmol/mg DNA。单点分析的结果是VG和SOG胞液受体浓度分别为26.13±5.64和8.40±1.66fmol/mg pro,VG明显高于SOG(P<0.01);胞核受体浓度分别为239.95±66.37和204.89±65.12fmol/mg DNA,两组比较无差异(P>0.05)。血清睾酮两组比较无统计学意义,并与胞液、胞核受体浓度无相关关系。     

DHAQ对HL-60细胞糖皮质激素受体含量及亲和力的影响

DHAQ是一种新型广谱高效抗癌药。本文采用放射配体结合法观察DHAQ对体外培养的HL-60细胞(人早幼粒白血病细胞)糖皮质激素受体(GCR)含量及亲和力的影响。一、Scarchard作图分析求得HL-60细胞R_0为93.3±8.56fmol/10~6细胞,kd为42.4±8.5nM。细胞经10~(-8)M DHAQ处理12小时,R_0降至40.8±3.67fmol/10~8细胞,Kd增至1.111±8.2nM。统计处理,差别显著。     

银杏内酯B对光化学诱导树鼩脑缺血时神经PAF受体结合特性的影响

目的 :观察光化学反应后 2 4ｈ中心区、半暗区ＰＡＦ受体结合特性 ,探讨血小板活化因子 (ＰＡＦ)受体拮抗剂 -银杏内酯Ｂ(ｇｉｎｋｇｏｌｉｄｅ ,ＧＢ)对脑缺血时神经元的保护机制。方法 :应用光化学诱导树鼠句局部脑缺血模型 ,于光化学反应后 6ｈ ,给药组舌下静脉一次注射ＧＢ 5ｍｇ/ｋｇ(ＧＢ组 ) ,对照组同时注射等量溶剂(溶剂组 )。检测ＧＢ组缺血中心区及半暗区的ＰＡＦ受体结合特性的变化。结果 :ＧＢ组半暗区两种ＰＡＦ受体亲和力 (ｋｄ分别为 3 0 9± 0 0 8ｎＭ(高亲和性受体 ,ｋｄ1 )及 1 1 34± 0 78ｎＭ(低亲和性受体 ,ｋｄ2 …     

树鼩脑局部血栓性缺血的扩布性抑制机制探讨

目的:观察树鼩血栓性脑缺血时,对侧神经元血小板活化因子(PAF)受体活化和神经元线粒体呼吸功能改变,探讨皮层扩布性抑制的可能机制。方法:采用光化学法诱导脑血栓形成,分别观察脑缺血对侧神经元超微结构、脑细胞膜PAF受体、单胺氧化酶(MAO)活性、单胺类递质含量以及神经元线粒体呼吸功能。结果:树鼩脑缺血时对侧皮层淤血,神经元线粒体肿胀;脑缺血4h对侧神经元PAF受体亲和量降低,其变化以24 h最为显著(P<0.01);缺血区线粒体Ⅲ态呼吸速率、呼吸控制率(RCR)及氧化磷酸化效率(P/O)均明显降低;缺血对侧皮层的P/O降低(P<0.05),Ⅲ态呼吸速率明显抑制(P<0.01);伴随着对侧脑组织MAO活性的升高(P<0.01),对侧皮层的去甲肾上腺素(NA)和5-羟色胺(5-HT)含量降低而5-羟吲哚乙酸(5-HIAA)含量明显升高(P<0.01)。结论:树鼩脑缺血时对侧皮层神经元PAF受体的活化以及MAO活性的增强可能在扩布性抑制的发生中具有重要作用。     

银杏内酯B对树鼩血栓性脑缺血后GFAP表达的影响及机制探讨

目的:观察树鼠句血栓性脑缺血形成后不同部位星形胶质细胞表达胶质纤维酸性蛋白(GFAP)的时间消长改变,以及血小板活化因子(PAF)受体拮抗剂银杏内酯B(GB)对GFAP表达的影响,并探讨其可能机制。方法:建立光化学诱导树鼠句血栓性脑缺血模型,用免疫组化法检测缺血后4、2 4、72hGFAP表达,最后用图像分析系统测定其平均灰度。结果:脑缺血后半暗区GFAP表达增多,以2 4h最为显著,其平均灰度值为6 0 .33±3 .0 9(P <0 . 0 1) ,72h表达仍高,其平均灰度值为6 0. 88±2 . 6 2 (P <0 . 0 1) ,此时对侧及远隔区GFAP表达增强。光化学反应后6h于舌下静脉注射GB(5mg/kg) ,发现缺血后2. 4h半暗区星形胶质细胞GFAP表达明显下调,与对照组相比有显著差异(P <0 . 0 5 )。结论:缺血性脑损伤后星形胶质细胞表达GFAP增多与神经元受损有关;GB通过拮抗血小板活化因子(PAF)对神经元的损伤作用使星形胶质细胞表达GFAP减少。     

缺血后适应对树鼩海马CA1区脑血流及星形胶质细胞活化的影响及可能机制

目的：研究缺血后适应（PC）对树鼩局部脑缺血海马CA1区脑血流（rCBF）与星形胶质细胞（AS）活化的影响，探讨缺血PC影响AS表达胶质纤维酸蛋白（GFAP)的可能机制。方法：建立树鼩血栓性局部脑缺血及缺血PC模型，通过激光多普勒（LD）血流计测量脑缺血后4 h、8 h、12 h、24 h及72 h海马CA1区rCBF的改变；用免疫组化法测定脑缺血上述时间海马GFAP的表达，并用图像分析系统测定其平均灰度值。于脑缺血后4 h重复3次夹闭缺血侧颈总动脉实施缺血PC，并观察其对海马CA1区rCBF和AS活化以及GFAP表达的影响。结果：树鼩脑缺血后4h海马CA1区GFAP阳性细胞数增多，AS表达GFAP增强，24h可见AS胀亡；72h海马CA1区AS表达GFAP达高峰（120.0±2.1，P＜0.01）。脑缺血时海马CA1区rCBF逐渐降低，以24 h的改变最显著,为(2.55±0.28) PU，P＜0.01；72 h时海马CA1区rCBF略有增加，为(9.84±1.22) PU。实施缺血PC后，海马CA1区rCBF逐渐增加，72 h最显著,为(18.74±1.60) PU，P＜0.01；此时海马GFAP表达进一步增强（111.0±1.3),P＜0.01。但AS胀亡的病理改变基本消失。结论：多次短暂的闭塞动物的颈动脉可延长树鼩脑缺血治疗的“时间窗”；缺血PC的脑保护机制可能与增加海马rCBF、调控AS活化及改善海马微环境有关。     

Changes in the edentate mandible in the elderly

Resorption of alveolar bone is the best recognized feature of mandibular aging in the edentate subject. The other consequences of the loss of teeth in the elderly are less well known. An anthropometric study of the mandible by antero-posterior and lateral radiographs of subjects older than 70 years both dentate and edentate but without any maxillo-mandibular dysmorphosis has been done to demonstrate the differences, which exist between the dentate and edentate mandible. The edentate mandibles showed a diminution in the height of the symphysis and increase in the height of the mandibular incisure. A diminution in the height of the body and an increase in the gonial angle in the significant manner. No significant difference was seen for the height of the ramus and the length of the mandible, the minimum width of the ramus and the bigonial width. The diminution in the height of the mandibular symphysis and of the body is explained by the resorption of the alveoli part of the mandible. The increase in the mandibular angle and the diminution in the height of the mandibular incisure may be explained by disequilibrium between the elevator and depressor muscles of the mandible, as a function of the elevator muscles or by the absence of the molar buttress.     

Stimulus specificity in the habituation of the startle response in the rat

A series of experiments evaluated whether the habituation of the startle response of the rat to tactile and auditory cues is stimulus specific. Experiment 1 showed stimulus specificity of a short-term habituation effect, whereby the startle to the second of a pair of stimuli was significantly less when the initial stimulus involved the same rather than the different modality. Experiments 2 and 3 focused on the more persistent decrement in startle that is a result of repeated stimulation, and demonstrated that such long-term habituation to the tactile and auditory stimuli contained a stimulus specific component in addition to a generalized component. The generalized habituation observed between the tactile and auditory stimuli in the three experiments may be due to an auditory accompaniment of the tactile stimulus employed. Discussion emphasized the utility of investigating habituation in a preparation with robust specificity.     

Spatio-temporal changes in the metabolic processes in the blood-tissue system in the terminal states of the organism

The role of synergism in diffusion of oxygen from erythrocyte into interstitial liquid and water filtration through the capillary wall was studied on the model using the following parameters: hydrostatic pressure on arterial and venous ends of the capillary (Pa and Pb), oncotic blood and tissue pressure (Pob and Pot), pore radius in the capillary (r), the number of pores in the capillary (n) per m2, amount of the liquid released from the capillary (q(x)), gas diffusion coefficient (D), time of erythrocyte movement in the capillary (T), speed of oxygen consumption (V), maximal distance with adequate V (Xmax), characteristic time of diffusion (Topt). It is shown that diffuse and convective components of the metabolic process have their own contribution and in changed conditions they redistribute. In increased number and diameter of hydravlic pores the greatest role in tissue saturation with oxygen belongs to convective metabolism, but in this situation tissues contain areas lacking oxygen.     

Challenges in the Management of Asthma in the Elderly

Recent literature has emphasized the clinical and socio-epidemiological significance of asthma in the elderly. However, why the disease burden remains high in this group is unclear. Elderly subjects usually have multiple chronic illnesses, and the role played by comorbidities in the context of asthma has been underappreciated. This review aims to summarize the literature associations between comorbidities and asthma in elderly patients. In addition, we discuss patient management issues.     

Changes in the testes following vasectomy in the rat

Six months and more after unilateral vasectomy in the rat, ipsilateral (same side) and bilateral testicular atrophy are common; this paper investigates their etiology. Ipsilateral atrophy is associated with the presence of a sperm granuloma in the head of the corresponding epididymis and appears to be pressure-mediated. That sperm granulomas at the epididymal head fail to relieve intraluminal pressure in the epididymal duct of the rat was supported by a study of the effects of ligation of that region. No histological evidence was found to indicate that bilateral atrophy was the result of an immune response. A radiological study does not support the idea that compression or displacement of testicular blood vessels by sperm granulomas is responsible for bilateral atrophy. © 1996 Wiley-Liss, Inc.     

Life in the Future Versus Life in the Present

Roemer and Orsillo have provided an integrative perspective for developing more effective therapies for generalized anxiety disorder, based on existing knowledge about the disorder, cognitive behavioral approaches to its treatment, and conceptualizations and treatment methods from the acceptance/mindfulness tradition. The present commentary expands upon the notion of the adaptive value of focused attention on present-moment experience and cognitive perspectives that can facilitate that process.     

Circulation in the lungs and microcirculation in the alveoli

Human lungs weighing ca 600 g permit the passage of 5–6 l of blood per minute. The blood capacity of the human lungs is about 0.5 l. Consequently, each 0.5 l of blood is during 5 s. The questions arise of how such a large mass of blood passes through such a small mass of lungs and what the reasons are for such a high rate of blood oxygenation. Since the structure of lungs in mammals is almost the same, we tried to solve these issues studying the rats, in which 20–22 ml of blood pass through the lungs of 1.5–2.0 g mass. A great blood flow appeared to be associated with a large diameter of the lung arterioles and a high rate of the blood flow in them. The high rate of oxygenation is accounted for by a special structure of alveoli and special conditions of the blood flow, which create ideal conditions for oxygen diffusion.