Michaelis—Menten兼有一级消除动力学模型平均稳态时的一些特性

本文将Rowland等人的二房室模型中的消除过程扩展成米氏兼一级消除过程。据此,推导出达到稳态浓度的时间、血药浓度-时间曲线下面积和生物利用度的公式;进而得到平均清除率和剂量间的关系以及剂量与平均清除率和血浆浓度呈线性关系的结论。     

环孢素胶丸的药代动力学和相对生物利用度

采用高效液相色谱法进行环孢素胶丸的药代动力学和生物利用度研究，１０名健康志愿者随机交叉单剂量ｐｏ温州第二制药厂和瑞士Ｓａｎｄｏｚ公司的环孢胶丸（２００ｍｇ），其血药浓度－时间曲线均符合一级吸收的双室模型，温州产环孢素胶丸的主要药动学参数ｔ１／２Ｋｄ＝１．０９±０．４６ｈ，ｔ１／２α＝０．３４±０．１５ｈ，ｔ１／２β＝５．１３±１．４１ｈ，ｔｍａｘ＝１．１９±０．１９ｈ，Ｃｍａｘ＝８７８．２±１６７．２ｎｇ／ｍｌ，ＡＵＣ＝４１２７．７±８５４．１ｎｇ·ｈ·ｍｌ－１，其相对生物利用度为（１０４．２±１１．９）％     

医学生人格特征形成的相关性研究

目的分析影响医学生人格特征形成的相关因素，为发展大学生的人格特征探寻其理论依据。方法用EPQ量表对601名医学生进行团体测验，其数据在WJZ心理测验软件上预处理后转入电子表格，用SPSS11．0软件进行统计学分析。结果EPQ量表中E、N、P、L的均值、标准差与常模比较，其差异有统计学意义；E，P，L3个维度间有不同程度的相关性：当以EPQ为因变量，15个影响因素为自变量进行逐步回归分析时，进入回归方程的主要是人际关系、家庭、学校教养(育)方式、经济状况、身心伤害否及自我形象、才能、专业的满意度。结论医学生的人格特征还处于发展阶段，其形戍过程与上述因素密切相关。     

Diet salinity and vasopressin as reproduction modulators in the desert-dwelling golden spiny mouse (Acomys russatus)

The time for reproduction in mammals largely depends on the availability of water and food in their habitat. Therefore, in regions where rains are limited to definite seasons of the year, mammals presumably will restrict their breeding correspondingly. But while mammals living in predictable ecosystems would benefit by timing their season to an ultimate predictable cue, such as photoperiod, in unpredictable ecosystems (e.g., deserts) they will need to use a more proximate signal. We suggest a mechanism by which water shortage (low water content in plants) could act as a proximate cue for ending the reproductive season. The golden spiny mouse (Acomys russatus), a diurnal rodent living in extreme deserts, may face an increased dietary salt content as the summer progresses and the vegetation becomes dry. Under laboratory conditions, increased diet salinity lead to reproductive hiatus in females, notable in imperforated vagina, and a significant decrease in the ovaries, uteri, and body masses. In females treated with vasopressin (VP), a hormone expressed during water stress, the uteri and body masses have decreased significantly, and the ovaries exhibited an increased number of atretic follicles. VP has also led to a significant decrease in relative medullary thickness (RMT) of the kidney. It is thus suggested that VP could act as a modulator linking the reproductive system with water economy in desert rodents, possibly through its act on the energetic pathways.     

Voronoi Polyhedra Analysis of Optimized Arterial Tree Models

Topological and metric properties of Voronoi polyhedra (VP) generated by the distal end points of terminal segments in arterial tree models grown by the method of constrained constructive optimization (CCO) are analyzed with the aim to characterize the spatial distribution of their supply sites relative to randomly distributed points as a reference model. The distributions of the number N _f of Voronoi cell faces, cell volume V, surface area S, area A of individual cell faces, and asphericity parameter of the CCO models are all significantly different from the ones of random points, whereas the distributions of V, S, and are also significantly different among CCO models optimized for minimum intravascular volume and minimum segment length (p < 0.0001). The distributions of N _f , V, and S of the CCO models are reasonably well approximated by two-parameter gamma distributions. We study scaling of intravascular blood volume and arterial cross-sectional area with the volume of supplied tissue, the latter being represented by the VP of the respective terminal segments. We observe scaling exponents from 1.20 ± 0.007 to 1.08 ± 0.005 for intravascular blood volume and 0.77 ± 0.01 for arterial cross-sectional area. Setting terminal flows proportional to the associated VP volumes during tree construction yields a relative dispersion of terminal flows of 37% and a coefficient of skewness of 1.12. © 2003 Biomedical Engineering Society. PAC2003: 8719Uv, 8710+e, 4720Ky, 0260Pn, 0230Oz     

The development of goal-directed reaching in infants: hand trajectory formation and joint torque control

Nine young infants were followed longitudinally from 4 to 15 months of age. We recorded early spontaneous movements and reaching movements to a stationary target. Time-position data of the hand (endpoint), shoulder, and elbow were collected using an optoelectronic measurement system (ELITE). We analyzed the endpoint kinematics and the intersegmental dynamics of the shoulder and elbow joint to investigate how changes in proximal torque control determined the development of hand trajectory formation. Two developmental phases of hand trajectory formation were identified: a first phase of rapid improvements between 16 and 24 weeks of age, the time of reaching onset for all infants. During that time period the number of movement units per reach and movement time decreased dramatically. In a second phase (28–64 weeks), a period of fine-tuning of the sensorimotor system, we saw slower, more gradual changes in the endpoint kinematics. The analysis of the underlying intersegmental joint torques revealed the following results: first, the range of muscular and motiondependent torques (relative to body weight) did not change significantly with age. That is, early reaching was not confined by limitations in producing task-adequate levels of muscular torque. Second, improvements in the endpoint kinematics were not accomplished by minimizing amplitude of muscle and reactive torques. Third, the relative timing of muscular and motion-dependent torque peaks showed a systematic development toward an adult timing profile with increasing age. In conclusion, the development toward invariant characteristics of the hand trajectory is mirrored by concurrent changes in the control of joint forces. The acquisition of stable patterns of intersegmental coordination is not achieved by simply regulating force amplitude, but more so by modulating the correct timing of joint force production and by the system's use of reactive forces. Our findings support the view that development of reaching is a process of unsupervised learning with no external or innate teacher prescribing the desired kinematics or kinetics of the movement.     

Relative growth of adenomatous polyps of the colon

Summary The volume of the adenomatous mucosa (V), the area of the surface epithelium (Ss), the area of the glandular epithelium (Sg), and theSg:Ss ratio were calculated in a series of 14 adenomatous polyps (APs) of a case of multiple polyposis of the colon. The equation of simple allometry was used to study the relative growth of the four series of values.Ss grew isometrically with size;Sg overgrewSs and accounted for most of the increase inV. TheSg:Ss ratio increased withSg andV.     

精神分裂症恢复期患者及家属家庭干预的对照研究

目的：以康复期出院精神分裂症患者和家属为对象，定期复诊进行家庭干预并对照研究。方法：干预组68例，对照组52例，采用BPRS评定；干预组家属74人，对照组家属65人，采用SCL－90评定。结果：6个月后干预组患者BPRS和入组时对照比较均有显著性差异（P＜0．01），说明干预组患者的精神症状，不良情绪及社会功能明显好转，入组时两组家属SCL－90评定与常模对照比较，均有明显差异（P＜0．05或0．01），经干预后干预组与全国常规比较无显著性差异（P＞0．05），说明患者家属普遍存在心理障碍，经干预后家属心理状况明显改善。结论：对康复期病人及家属进行门诊家庭干预，是有效的康复方法，值得推广应用。     

Delayed responses to electrical stimuli reflect C-fiber responsiveness in human microneurography

The slowing of impulse conduction during the relative refractory period has often been used to assess activation of C-fibers, in particular, in human microneurography. This study aimed to evaluate the sensitivity of this method and the factors affecting it. Thirty cutaneous C-fibers were recorded from the peroneal nerves of healthy human subjects. Intracutaneous electrical stimulation in the receptive field at 4 s intervals, after some minutes of adaptation, induced spike discharges at constant latency. One or more conditioning stimulus pulses were interpolated at different intervals and the increase in latency after the subsequent regular pulse was assessed. The latency shift was found to depend on the number of interposed pulses, on the time interval between conditioning and conditioned stimulus, and on the conduction velocity of the C-unit. The increase in latency was larger with greater distance between stimulating and recording electrodes, indicating a contribution of the conductile membrane over its whole length. On the other hand, slowing was more pronounced, on average, in slower conducting C-units and conduction velocities were slower when recordings were performed more distally. These findings indicate that the slower terminal nerve branches contribute most to the latency increases. Even a single additional spike in between two regular pulses caused a reliable latency shift of 1.2±0.2 ms (mean ±SEM) and additional pulses lead to an approximately linear latency increase (2 pulses: 2.3±0.3 ms; 4 pulses: 5.9±0.7 ms). In contrast to the number of interposed stimuli, different intervals between interposed and regular stimuli had only a minor impact on the latency shifts. It is concluded that latency shifts are reliable indicators of C-fiber activation, being sensitive enough to detect even single spike responses. Furthermore, latency increases may be used as a relative measure of C-fiber activation, e.g., when comparing responses to stimuli of different strength.     

Bioavailability of oestradiol and oestriol administered orally to oophorectomized women

A bioavailability study was performed on ten oophorectomized women in a randomized cross-over design. The absorption of tablets containing 2 mg of micronized oestradiol and 1 mg of micronized oestriol (Estrofem®) was compared to the absorption of the same micronized hormones administered in an aqueous suspension. Serum concentration values of oestradiol, oestriol and oestrone were measured by radioimmunoassay. The data obtained were analyzed both by univariate and multivariate analyses, and neither the serum concentrations at the various sample times, the maximum concentrations, the times for the maximum concentrations, nor the areas under the serum concentration curves disclosed any significant differences between the tablet and suspension administrations at the 5% level. The serum concentration values achieved by giving 2 mg of oestradiol and 1 mg of oestriol were of the same magnitude or higher than those of the normal menstrual cycle.