头孢克洛在健康人体内的药物动力学研究

采用ＨＰＬＣ测定健康志愿者血浆中头孢克洛的浓度。方法简便快速，结果准确。平均回收率为１０２．１８±４．０１％，日间及日内ＲＳＤ均小于６％。血药浓度－时间曲线符合一室模型。     

Human balance and posture control during standing and walking

The common denominator in the assessment of human balance and posture is the inverted pendulum model. If we focus on appropriate versions of the model we can use it to identify the gravitational and acceleration perturbations and pinpoint the motor mechanisms that can defend against any perturbation.

We saw that in quiet standing an ankle strategy applies only in the A/P direction and that a separate hip load/unload strategy by the hip abd/adductors is the totally dominant defence in the M/L direction when standing with feet side by side. In other standing positions (tandem, or intermediate) the two mechanisms still work separately, but their roles reverse. In the tandem position M/L balance is an ankle mechanism (invertors/evertors) while in the A/P direction a hip load/unloading mechanism dominates.

During initiation and termination of gait these two separate mechanisms control the trajectory of the COP to ensure the desired acceleration and deceleration of the COM. During initiation the initial acceleration of the COM forward towards the stance limb is achieved by a posterior and lateral movement of the COP towards the swing limb. After this release phase there is a sudden loading of the stance limb which shifts the COP to the stance limb. The COM is now accelerated forward and laterally towards the future position of the swinging foot. Also M/L shifts of the COP were controlled by the hip abductors/adductors and all A/P shifts were under the control of the ankle plantar/dorsiflexors. During termination the trajectory of both COM and COP reverse. As the final weight-bearing on the stance foot takes place the COM is passing forward along the medial border of that foot. Hyperactivity of that foot's plantarflexors takes the COP forward and when the final foot begins to bear weight the COP moves rapidly across and suddenly stops at a position ahead of the future position of the COM. Then the plantarflexors of both feet release and allow the COP to move posteriorly and approach the COM and meet it as quiet stance is achieved. The inverted pendulum model permitted us to understand the separate roles of the two mechanisms during these critical unbalancing and rebalancing periods.

During walking the inverted pendulum model explained the dynamics of the balance of HAT in both the A/P and M/L directions. Here the model includes the couple due to the acceleration of the weight-bearing hip as well as gravitational perturbations. The exclusive control of A/P balance and posture are the hip extensors and flexors, while in the M/L direction the dominant control is with the hip abductors with very minor adductor involvement. At the ankle the inverted pendulum model sees the COM passing forward along the medial border to the weight-bearing foot. The model predicts that during single support the body is falling forward and being accelerated medially towards the future position of the swing foot. The model predicts an insignificant role of the ankle invertors/evertors in the M/L control. Rather, the future position of the swing foot is the critical variable or more specifically the lateral displacement from the COM at the start of single support. The position is actually under the control of the hip abd/adductors during the previous early swing phase.

The critical importance of the hip abductors/adductors in balance during all phases of standing and walking is now evident. This separate mechanism is important from a neural control perspective and clinically it focuses major attention on therapy and potential problems with some surgical procedures. On the other hand the minuscule role of the ankle invertors/evertors is important to note. Except for the tandem standing position these muscles have negligible involvement in balance control.     

Shared care: a review of the literature

This review examines broad issues of concern regarding the primary/secondarycare interface. The main purpose was to identify areas of goodpractice which could be adapted for more general use. One ofthe most fundamental aspects identified was communication, whichis discussed in some detail. Also covered are shared prescribingand disease management. The data suggest that the most effectivesystem(s) of shared care has yet to be established. Furtherqualitative and economic evaluations are required, taking intoaccount patient preferences. Although the literature does describecertain practice exemplars, it is clear that inter- and intra-professionalcommunication continues to be a problem. Whilst informationtechnology may provide some of the solutions, it is concludedthat a culture change, which compels health professionals tomake sharing of patient information a much higher priority,is reauired. Keywords. Shared care, seamless care, hospital, general practice, family practice.