Changes of Unit Discharge of the Medullary Respiratory Neurons during Apnea

Changes of the neuronal discharge of 128 medullary respiratory unitswere recorded and studied during the period of expiratory apnea induced reflexlyby intracarotid sinus injection of sodium citrate in rabbits.Generally,theneuronal discharge of inspiratory units began,stopped and recovered at the sametime with those of the phrenic nerve.But,about 5% the phase-spanninginspiratory units near the obex showed a different time course with the dischargeof the phrenic nerve.They fired continuously in a low frequency while thephrenic nerve was quiet.When increasing progressively and approaching to acertain level,the firing rate increased abruptly and at the same time phrenic nervebegan to fire.So it seemed that they acted as the pacemaker of inspiration.Comparison of the cycle-triggered histograms(CTH)of these inspiratory unitswith those of phrenic nerve showed clearly the above mentioned phasicrelationship.They started firing before the phrenic nerve,but they reached theirmaximal rate and then declined and stopped quite in accordance with the phrenicnerve.It is,therefore,reasonable to assume that the central mechanism of theswitch from expiratory apnea to inspiration may originate from this kind ofneurons.Most of the expiratory units show tonic discharges during the period of apneawith a higher discharge rate than normal and then the rate decreases just beforerecovery of phrenic firing.In addition,small portion of the expiratory units weredepressed as the phrenic discharge ceased.The function of these two differentkinds of neurons in the mechanism of development of respiratory rhythm is,apparently,different.     

恒定分压CO2对羟基磷灰石溶解度的影响

[目的]应用固体滴定技术监测羟基磷灰石(Hydroxyaptite,HA)的溶解平衡过程,观察组织液生理浓度CO2对羟基磷灰石溶解度的影响.[方法]在恒温水浴系统中以HA为固体滴定物.测试液为KCl溶液(0.1 mol/L),并引入恒定分压的CO2(占空气体积比为3.5%±0.1%).半导体二极管激光为发射光源,散射光源探测器用于监测HA的溶解平衡过程并判断超越溶解平衡点所出现的沉淀(合共17次滴定终点).固体滴定总量用于代表溶解度等温线上的数据点.[结果]引入恒定分压CO2后测定的HA在KCl溶液中的溶解度高于其在KCl溶液中所得50倍以上.[结论]固体滴定技术利于监测HA的溶解平衡过程.溶液体系中CO2增加HA的溶解度.推测该现象与CO2-3形成的复合物密切相关.     

hTERT启动子调控hNIS基因介导肺癌细胞碘摄取和131I治疗的实验研究

目的 构建含人端粒酶反转录酶(hTERT)核心启动子调控的人钠/碘同向转运体(hNIS)基因重组腺病毒,并靶向转染至肺癌A549细胞中特异性表达.探讨hTERT启动子调控的hNIS基因介导放射性碘治疗肿瘤的可能性.方法 应用AdEasy系统构建重组腺病毒Ad-hTERT-hNIS,同时构建巨细胞病毒(CMV)启动子调控的hNIS重组腺病毒Ad-CMV.hNIS作为阳性对照,不含hNIS的重组腺病毒Ad-CMV作为阴性对照.应用反转录.聚合酶链反应(RT-PCR)方法验证hTERT在转染肿瘤细胞中的转录活性,摄碘实验检测表达的hNIS蛋白功能,细胞克隆形成实验评价131I对转染肿瘤细胞的毒性作用.结果 成功构建重组腺病毒Ad-hTERT-hNIS、Ad-CMV-hNIS及Ad-CMV,并经PCR验证正确.RT-PCR证实hNIS cDNA能从Ad-hTERT-hNIS转染的细胞中扩增出来.Ad-hTERT-hNIS和Ad-CMV-hNIS转染的肺癌A549细胞摄碘能力比阴性对照组Ad-CMV转染的细胞分别提高了23和31倍,且摄碘能力可以被NaClO4抑制.Ad-hTERT-hNIS和Ad-CMV-hNIS转染的肺癌A549细胞均可被131I杀死,2组细胞成活率分别为(31.2±1.45)%和(23.6±4.08)%,而阴性对照组和未转染病毒组分别为(89.0 ±2.99)%和(91.2 ±4.63)%.结论 hTERT启动子调控的hNIS重组腺病毒转染肿瘤细胞后,应用131I治疗有望成为一种新的基因靶向治疗手段.     

磷酸钙水泥填充固定桡骨远端骨折的抗旋转生物力学研究

目的对磷酸钙水泥(CPC)填充固定桡骨远端骨折的抗旋转应力进行评价,并与传统的克氏针固定方法进行比较。方法18根人桡骨标本制备桡骨远端骨折伴骨缺损模型,随机分为三组:克氏针固定组、CPC固定组和CPC 克氏针联合固定组。设定扭转速度为5°／min,最大扭转角度为10°时停止。记录扭转刚度、10°内的最大扭矩及所对应的最大扭角。结果在10°的扭转范围内,CPC固定组、CPC 克氏针联合固定组的扭转刚度、最大扭矩均比克氏针固定组大,差异有统计学意义(P< 0．01);最大扭转角度分别为4．3°和5．0°,均比克氏针组(9．6°)小,差异有统计学意义(P<0．01)。CPC固定组与CPC 克氏针联合固定组之间的扭转刚度、最大扭矩及最大扭角差异无统计学意义(P> 0．05)。结论在旋转角度小于4°范围内,CPC的抗旋转固定强度要比克氏针大,超过这个范围,骨水泥就会发生断裂,CPC的有效固定范围比克氏针要小。     

复合干细胞生物陶瓷在裸鼠异位成骨中的评价

目的 研究h-BMP-2基因转染骨髓间充质干细胞(BMSCs)在复合煅烧骨、β-TCP或直接植入裸鼠股部后的成骨能力。方法 通过影像学、组织学和形态计量学等方法,观察未经诱导、OS液诱导和h-BMP-2基因转染BMSCs在复合煅烧骨,或多孔β-TCP后植入裸鼠皮下,或直接制成细胞悬液注入,在4、8、12周诱导成骨和材料降解情况。结果 在裸鼠皮下,单纯生物陶瓷不能诱导成骨,而复合了未诱导、OS液诱导和h-BMP-2基因转染BMSCs的生物陶瓷均能成骨,成骨量为h-BMP-2基因转染组>OS液诱导组>未经诱导组(P<0.05),B-TCP可随骨长入而降解;注入裸鼠肌肉的OS液诱导的和h-BMP-2转染的BMSCs均能诱导成骨,而未经诱导MSCs则不能成骨。结论 复合人BMP基因转染BMSCs的β-TCP是一种理想的骨修复材料。     

自固化磷酸钙人工骨修复骨缺损的临床应用

目的:探讨自固化磷酸钙人工骨(CPC)填充修复骨缺损的临床效果。方法:骨缺损94例,男59例,女35例;年龄11~72岁,平均39.4岁。骨缺损部位:胸腰椎38例,跟骨25例,胫骨15例,股骨7例,肱骨近端3例,桡骨远端5例,近节指骨1例。骨缺损原因:骨折塌陷复位后骨缺损63例,骨髓炎20例,骨囊肿6例,骨纤维异常增殖症4例,内生软骨瘤1例。骨缺损范围为1cm×1cm~4cm×20cm,用CPC填充修复,CPC充填量为3~42g,其中单纯CPC填充修复74例(胸腰椎骨折行椎体成形38例,骨折复位后空腔充填25例,良性骨肿瘤病灶刮除后充填11例),载药CPC填充修复骨髓炎20例。结果:所有患者均获随访,随访时间14~48个月,平均29.6个月。全部患者术后未见过敏或毒性反应,无皮疹或高热,血钙、磷、碱性磷酸酶均正常,切口无瘙痒感。随访时X线片显示,植入CPC与宿主骨接触紧密,界面处未见间隙存在,骨缺损处的解剖形状完全或大部分恢复,未见脱落现象,随访时部分患者CPC部分降解成骨。9例发生术后伤口渗出,为淡黄色清亮稀薄分泌物,细菌培养阴性,经换药后伤口愈合良好。结论:CPC填充修复骨缺损安全有效,并发症少,是理想的骨替代品,载药CPC是治疗骨髓炎的理想方法。     

Gold complex research in medical science. Difficulties with experimental design

Despite the use of gold complexes in modern medicine for over 100 years and the use of gold complexes in the management of rheumatoid disease for more than 60 years, the definitive mechanisms of action for efficacy and for toxicity have not been established. Gold is a group 1b metal in the periodic table with several oxidation states but it is only Au(I) which is active in the biological milieu. Gold sodium thiomalate is not only a polymeric structure, but also has the chiral ligand, thiomalic acid. Gold sodium thiomalate thus can exist in several different physical states which may have different biological activity. In addition the pharmacokinetic profile of gold complexes has been of little value in the understanding of either the mechanism of action, efficacy or toxicity for both the injectable and the oral gold complexes. Many authors have misinterpreted research data on the activities of gold complexes because they compared gold complexes of different structures, and gold complexes which exist at different pH. Experimental work in our laboratory has identified that gold sodium thiomalate is a mixture and can exist as either a yellow or a colourless solution. These have some similar but several different biological activities. Many factors contribute to the lack of understanding of the action of gold complexes. Some of these factors are related to the wide variation in physical structure and biological activities exhibited by these compounds.     

4－甲氧基－2－巯基－N－氧化吡啶钠的抗肿瘤及免疫抑制作用

４－个甲氧基－２－巯基－Ｎ－氧化吡啶钠（４－甲氧基巯氧吡啶钠，ＳｏｄｉｕｍＭｅｔｈｏｘｙｐｙｒｉｄｉｎｅｔｈｉｏｎｅ，ＳＭＰＴ）在试管内０．０１ｍｇ·Ｌ－１可抑制多种传代人癌细胞林，抑制细胞有丝分裂和损害细胞膜相结构，单用对动物移植性肿瘤无效，但明显增强氟脲嘧啶对小鼠Ｓ１８０的抑癌作用。使胸腺和脾脏重量明显减轻，抑制ＳＲＢＣ诱导的小鼠血清溶血素反应，抑制ＤＮＣＢ诱导的豚鼠皮肤迟发型超敏反应，抑制ＰＨＡ诱导的大鼠３Ｈ－ＴｄＲ参入的淋巴细胞转化。与２－巯基－Ｎ－氧化吡啶钠（巯氧吡啶钠，ＳｏｄｉｕｍＰｙｒｉｄｉｎｅｔｈｉｏｎｅ．ＳＰＴ）比较，小鼠ＬＤ５０（ｉｐ）增大，而试管内抑瘤的ＩＣ５０相近。     

亚硒酸钠诱导白内障的机理研究

在pH8.0-8.5条件下,谷胱甘肽、氧或过氧化氢过量时,微量的10~(-4)mol·L~(-1)亚硒酸钠能使鲁米诺产生稳定的化学发光。发光强度依赖于酸度、谷胱甘肽浓度、氧及过氧化氢的浓度。超氧化物歧化酶(SOD)对鲁米诺发光有明显的抑制作用。SeO_3~(2-)在眼内催化产生活性氧可能是产生白内障的原因。     

BIOCHEMICAL CORRECTION IN THE SYNDROME OF HYPERTENSION AND HYPERKALAEMIA BY SEVERE DIETARY SALT RESTRICTION SUGGESTS RENIN-ALDOSTERONE SUPPRESSION CRITICAL IN PATHOPHYSIOLOGY

1. Plasma potassium and chloride concentrations were raised and plasma renin activity, aldosterone, bicarbonate and arterial pH were reduced in two brothers with the syndrome of hypertension and hyperkalaemia with normal glomerular filtration rate (Gordon's syndrome), on unrestricted or moderately restricted sodium diets. 2. These abnormalities were corrected in both patients within 10 days of severe sodium restriction. 3. Pressor sensitivity to cold and angiotensin II decreased on low sodium diet, associated with a fall in blood pressure. 4. Increasing distal tubular sodium delivery by infusion of normal saline increased fractional excretion of potassium when aldosterone had been stimulated by severely restricted sodium diet, but not when aldosterone levels were low on unrestricted sodium diet. 5. These findings are consistent with excessive sodium reabsorption as the primary renal lesion in Gordon's syndrome, leading to volume expansion and suppression of renin and aldosterone. Severe dietary sodium restriction leading to volume contraction, by stimulating renin and aldosterone and promoting kaliuresis, corrects the abnormalities.