Acute Immobilization Stress and Intraventricular Injection of CRF Suppress Naloxone-Induced LH Release in Ovariectomized Estrogen-Primed Rats

The present study was undertaken to evaluate the role and possible interaction of the endogenous opioid peptide (EOP) and corticotropin-releasing factor (CRF) in the acute stress-induced suppression of gonadotropin secretion in ovariectomized estrogen-primed rats. An intravenous (i.v.) injection of naloxone (10 or 20  mg/kg), an EOP antagonist, significantly elevated serum luteinizing hormone (LH) levels within 10  min in non-stressed animals. The naloxone-induced LH release was completely eliminated when tested 30  min after the onset of acute immobilization. In a subsequent study, it was found that suppression of the naloxone-induced LH release occurred as early as 5  min after the stress onset, and was still evident 60  min after the end of a 30-min period of immobilization. The effect of naloxone was restored 3  h after liberation of the animal from the 30-min immobilization. An intraventricular (i.c.v.) injection of CRF (1 or 5  μg) also significantly suppressed, in a dose-related manner, the effect of a subsequent i.v. injection of naloxone. However, an i.c.v. injection of α -helical CRF(9-41) (25 or 50  μg), a CRF antagonist, prior to immobilization, could not interfere with the suppressive effect of stress on naloxone-induced LH release. These results suggest that both acute immobilization stress and CRF can inhibit the LH secretory activity without mediation by EOP neurons. However, the stress-related suppression may involve non-CRF mechanism(s).     

固定化脂肪酶催化大豆油制备生物柴油

研究了脂肪酶固定化及其催化大豆油制备生物柴油的工艺。采用溶胶-凝胶法对脂肪酶进行了固定化,考察了固定化酶催化大豆油转酯化的生产工艺中酶用量、醇油比、含水量、反应温度、反应时间、溶剂等参数对转酯过程的影响。实验结果表明,当大豆油4.5 g时,最佳的反应条件为：固定化酶646 mg,醇油摩尔比4∶1,含水质量分数为6%,40℃,甲酯的最终转化率为96.33%。     

The effects of training, immobilization and remobilization on musculoskeletal tissue

Compared with the knowledge on immobilization, the effects of remobilization on musculoskeletal tissues have not been well established. What is sure is that remobilization and rehabilitation of any component of the musculoskeletal tissues require much more time than the time needed to cause the immobilization atrophy. With intensive rehabilitation, the functional properties of skeletal muscles can be improved significantly even years after the injury and following immobilization, but no study has shown whether full recovery is possible and whether these rehabilitated muscles are able to respond normally to further training. Experimental studies have given evidence that slow-twitch muscle fibres have better capacity for recovery than fast-twitch fibres, most likely due to better circulation and higher protein turnover. Also evidence has been given that fibre regeneration is possible through satellite cell activation and myotube formation. Very little is known, however, about the effects of age, gender or the level of preimmobilization muscle performance on the restoration capacity. Also the fate of the marked structural changes (for example, connective tissue accumulation) induced by immobilization is unknown. Tendon and ligament tissues are likely to respond appropriately to remobilization, resulting in acceleration of collagen synthesis and fibril neoformation. However, there is a strong suspicion that remobilized tendons and ligaments will not achieve all the biochemical and biomechanical properties of their healthy counterparts. Specifically, the amount of weak type III collagen has been shown to be overrepresented in these tissues instead of mature, strong type I collagen. It is not known whether this is an important risk factor for ruptures during later activity. The effects of remobilization on muscle-tendon junction and proprioceptive organs are not known. It would not be surprising if the serious structural changes induced by immobilization were unrestorable. In the literature dealing with immobilization and remobilization, cartilage degeneration is always a major concern, because not only too strenuous training or immobilization, but also unskilful remobilization may activate this process leading finally to osteoarthrosis. Bone may be one of the best components of musculoskeletal tissues to respond to remobilization, probably because the immobilization atrophy of bone is largely quantitative (osteoporosis) only. The prerequisites for bony recovery are that the follow-up time is long enough (months) and that immobilization has not exceeded about 6 months, the time limit between active and inactive (irreversible) osteoporosis. Prevention of the atrophying effects of immobilization can be very successful if performed properly. According to present knowledge, there are many methods for the purpose, including preimmobilization training early, controlled mobilization; optimal positioning of the immobilized joint; muscular training during immobilization; early weightbearing; exercise with the nonimmobilized extremity; and electrical stimulation. Lots of education and information will be needed, however, before these methods are deeply rooted in the daily routines of the attending physicians, physical therapists, athletic trainers and other persons involved in the treatment of musculoskeletal problems.     

Immobilization Related to Early Linear Growth

ABSTRACT. This study shows that children with late-diagnosed congenital dislocation of the hip (CDH) have close to normal height development during the initial 6.0 years of life. The treatment consisted of immobilization for 0.5 to 1.3 years starting between 0.2 and 0.7 years of age. The present work addresses one specific issue that is related to the age at onset of the childhood component of the ICP growth model. The onset normally appears between 0.5 and 1.0 year of age, and is recognized as an increase in length/height velocity. The onset is thus found during a period of increasing motor activity. The normal successive change from sitting to walking position may have some influence on the onset of this tempo change in early linear growth. The present documentation implies that there is no such influence. In all 14 children with CDH, the onset manifested during the period of immobilization, and the average age at onset was found to be Virtually equivalent with that of the controls. Our conclusion is that immobilization has no significant influence on the age at onset of the childhood phase of growth. The onset is accomplished independent of body position, be it lying down or normal for the age.     

Indirect detection of anti-acetylcholinesterase compounds in microcolumn liquid chromatography using packed bed reactor with immobilized human red blood cell acetylcholinesterase and choline oxidase

The inhibiting compounds were separated by micro-column liquid chromatography in the mobile phase containing the natural substrate acetylcholine. A home-made packed bed microbioreactor system containing immobilized enzyme acetylcholinesterase (ACHE) in human red blood cell membrane and choline oxidase (CHO) from alcaligenes was used for the post-column conversion of acetylcholine to hydrogen peroxide which was detected by an electrochemical detector. The inhibition effect of the solutes caused a decrease in the acetylcholinesterase activity, a decrease in the formation of hydrogen peroxide and also a decrease in the response corresponding to the concentration of the solutes. The rate of the enzyme regeneration was also recorded. The micro-system was compared with a conventional LC system comprising commercially prepared enzyme reactor. The stability of the enzymes is at least 3 weeks at ambient temperature. The limit of detection depends on biological activity of inhibition and for galanthamine was 1 pmol.     

ULTRASTRUCTURAL INVESTIGATION ON THE ARTICULAR CARTILAGE FROM RABBIT KNEE JOINT AFTER IMMOBILIZATION IN CAST

The articular cartilages from the left knee of 30 rabbits immobilized in casts in functional position were studied under transmission electron microscope. The pathological changes which begin at early stage of immobilization included both degeneration and repair of cartilage. The striking morphological features observed were: (1) most chondrocytes in various layers of cartilage underwent progresive degeneration; (2) the concomitant abnormal proliferation of some chondrocytes happened in a brief period. The changes in mechanical stress caused by immobilization affected the nutrition of cartilage and finally led to its reactive structural reformation.     

Effects of immobilization stress on hippocampal monoamine release: Modification by mivazerol, a new α2-adrenoceptor agonist

Mivazerol is a new and selective α₂-adrenoceptor agonist which has demonstrated anti-ischemic effects, both in animals and in patients with myocardial ischemia. In the present study, mivazerol was evaluated for its ability to inhibit the release of catecholamines and serotonin (5-HT) in the hippocampus of freely moving rats, and also was compared to clonidine. In vivo microdialysis in combination with high-performance liquid chromatography (HPLC) was employed. Intravenous administration of mivazerol (8.0 μg/kg) had no effect on basal outflow of norepinephrine (NE), dopamine (DA) and 3,4-dihydroxyphenylacetic acid (DOPAC). In contrast, clonidine (8.5 μg/kg, i.v.) attenuated the basal release of DOPAC, which has been proposed to reflect NE biosynthesis, suggesting that clonidine has an inhibitory effect on NE synthesis. In addition, both mivazerol and clonidine decreased the spontaneous release of 5-HT, which provided further evidence that α₂-adrenoceptors in the hippocampus modulate 5-HT. Sixty-min immobilization stress significantly increased the release of NE (177 ± 28%), DA (209 ± 46%) and DOPAC (337 ± 72%). Mivazerol (2.5, 8.0 and 25 μg/kg, i.v.) completely prevented the immobilization stress-induced enhancement of NE, DA and DOPAC, which was equi-effective to clonidine at a dose of 8.5 gmg/kg, i.v. These findings demonstrate that mivazerol has a profound modulatory effect on stress-induced neurotransmitter release in the hippocampus, at dose levels reported to protect against myocardial ischemia.     

离子交换树脂吸附法固定化脂肪酶的研究

以D311离子交换树脂为载体,通过离子交换吸附法对Lipolase100L脂肪酶进行了固定化。采用考马斯亮蓝法测定了酶蛋白在离子交换树脂上的吸附率,考察并得到了酶固定化的最佳条件：在pH10缓冲液下,加酶液量为每克预处理过的树脂加入1.5mL,吸附时间为10h,吸附温度为35℃。所得固定化酶用于催化合成月桂酸月桂醇酯,在反应物质的量比为1∶1时,水质量分数为8%,在50mL异辛烷有机溶剂中固定化酶用量为200mg,反应时间为210min,温度为55℃的最佳条件下,酯化率可达91.3%。     

人血管抑制因子的原核表达、纯化及活性研究

目的：利用大肠杆菌表达系统表达人血管抑制因子，并利用镍金属螯合层析法进行纯化，探讨其抑制血管内皮细胞增殖的活性。方法：采用RT-PCR技术从人肝脏组织中获取人血管抑制因子的cDNA，将其克隆至原核表达载体pQE30中进行IPTG诱导表达。表达产物经SDS-PAGE分析，并利用镍金属螯合层析法进行纯化。^3H-TdR法检测纯化的血管抑制因子对血管内皮细胞增殖的抑制作用。结果：利用pQE30表达载体表达的含6个组氨酸尾的vasostafin蛋白，在SDS-PAGE上表现出一条约2lkD的阳性条带，经镍金属螯合层析纯化后的蛋白经肽指纹图谱分析鉴定为目的蛋白，在体外可抑制人脐静脉血管内皮细胞的增殖。结论：人血管抑制因子可在大肠杆菌中以包涵体形式高水平表达，并具有抑制血管内皮细胞增殖的活性．