Time-course response

Fig. 1. Relative F-actin time-course response of human neutrophils exposed to 10- MFMLP at 37°C.

Fig. 3. Relative F-actin time-course responses of neutrophils sequentially exposed to 10 M LTB4 for 5 min and 10 M FMLP for 5 min ( ) are compared with the response of neutrophils exposed to 10 M FMLP alone (O). The arrow indicates when 10 M FMLP was added to the cell suspensions.

Time-Course Response. The chronological effect of BR is characteristic. As shown in Figure 3, BR also shows a biphasic response pattern similar to that of IAA (32). The first phase is presumably ascribed to acid growth. The unique pattern of BR-induced response is that the second phase lags behind that of the IAA-induced second phase by 6 h. This may indicate that the action of BR is not immediate as far as elongation is concerned. 

Figure 3. Time-course responses of hypocotyl sections to brassinolide and IAA.

The MCQ can be administered using paper and pencil forms or using a computerized version. Advantages to the paper and pencil method are that it requires no equipment other than the form, a pencil, and perhaps a clipboard however, it will have to be scored by hand, which introduces the possibility of human error. A computerized version presents the MCQ items one at a time, and participants respond using the mouse or keyboard to move a cursor to indicate their response. Repeated administration of the MCQ should continue for sufficient time to observe a complete time course. Responses to tobacco imagery cues have been shown to remain at peak levels for at least 15 min (8). 

Transient, or time-resolved, techniques measure tire response of a substance after a rapid perturbation. A swift kick can be provided by any means tliat suddenly moves tire system away from equilibrium—a change in reactant concentration, for instance, or tire photodissociation of a chemical bond. Kinetic properties such as rate constants and amplitudes of chemical reactions or transfonnations of physical state taking place in a material are tlien detennined by measuring tire time course of relaxation to some, possibly new, equilibrium state. Detennining how tire kinetic rate constants vary witli temperature can further yield infonnation about tire tliennodynamic properties (activation entlialpies and entropies) of transition states, tire exceedingly ephemeral species tliat he between reactants, intennediates and products in a chemical reaction. 

FIGURE 5.15 Different modes of response measurement, (a) Real time shows the time course of the production of response such as the agonist-stimulated formation of a second messenger in the cytosol, (b) The stop-time mode measures the area under the curve shown in panel A. The reaction is stopped at a designated time (indicated by the dotted lines joining the panels) and the amount of reaction product is measured. It can be seen that in the early stages of the reaction, before a steady state has been attained (i.e., a plateau has not yet been reached in panel A), the area under the curve is curvilinear. Once the rate of product formation has attained a steady state, the stop-time mode takes on a linear character. 

FIGURE 5.16 The effect of desensitization on stop-time mode measurements. Bottom panels show the time course of response production for a system with no desensitization, and one in which the rate of response production fades with time. The top dose response curves indicate the area under the curve for the responses shown. It can be seen that whereas an accurate reflection of response production is observed when there is no desensitization the system with fading response yields an extremely truncated dose-response curve. 

Fig. 3. Time course of cellular responses to turgor perturbation. Biophysical...

Hauser AE, Debes GF, Arce S et al (2002) Chemotactic responsiveness toward hgands for CXCR3 and CXCR4 is regulated on plasma blasts during the time course of a memory immune response. J Immunol 169 1277-1282... 

Kudo FA, Warycha B, Juran PJ, Asada H, Teso D, Aziz F (2005) Differential responsiveness of early- and late-passage endothehal cells to shear stress. Am J Surg 190(5) 763-769 Lee RH, Efron D, Tantry U, Barbul A (2001) Nitric oxide in the healing wound a time-course study. J Surg Res 101(1) 104-108... 

In our patch clamp studies in excised membrane patches in which we attempted to characterize the Cl we have noted that Cl did not only inhibit the probability of the ICOR channel being open but we also found that the input conductance of the patch was reduced at the same time and with the same time course [72]. We have followed up on this observation and we were able to show that this reduction in input conductance is caused by an inhibition of small ( lOpS) Cl -channels. Hence, we postulate that the same patches containing ICOR channels also contain small (unresolved, cf. section 2.4) Cl -channels which are inhibited reversibly by CL It cannot be excluded at this stage that these small Cl -channels are responsible for the defect in CF. 

Interpretation of methylation rate measurements can be complex because of the need to understand the time course of methylation/demethylation, and the dose-response to different levels of spiking, which can have a profoimd effect on the... 

FIG. 14 Time course of the (O) EMF and ( ) SHG responses of 1,2-dichloroethane containing no TDDMA-SCN upon a concentration step from 0 to 10 M KSCN. (From Ref. 16.)... 

FIG. 6 Time-course changes of potential response for silicone-rubber-membrane Na+-selective electrodes based on neutral carriers (5), (2), and bis(12-crown-4) on changing Na concentration from 1 X 10 to 3 X 10 M. (From Ref. 22.)... 

Pierce NF, Fedson DS, Brigham KL, et al. The ventilatory response to acute base deficit in humans. Time course during development and correction of metabolic acidosis. Ann Intern Med 1970 72 633-640. 

Cytotoxic chemotherapy is eventually required in most patients with metastatic breast cancer. Patients with hormone-receptor-negative tumors require chemotherapy as initial therapy of symptomatic metastases. Patients who respond initially to hormonal manipulations eventually cease to respond and go on to require chemotherapy. The median duration of response is 5 to 12 months, but some patients will have an excellent response to an initial course of chemotherapy and may live 5 to 10 years or longer without evidence of disease. In general, median survival of patients after treatment with commonly used drug combinations for metastatic breast cancer is 14 to 33 months. The median time to response has ranged from 2 to 3 months in most studies, but this period depends in large part on the site of measurable disease. The median time to appearance of response is between 3 and 6 weeks in patients whose disease is primarily in the skin and lymph nodes, 6 to 9 weeks in patients with metastatic lung involvement, 15 weeks in patients with hepatic involvement, and nearly 18 weeks in patients with bone involvement. Thus it is often the case that an immediate response to therapy is not... 

Drug therapy is a dynamic process. When a drug product is administered, absorption usually proceeds over a finite time interval, and distribution, metabolism, and excretion (ADME) of the drug and its metabolites proceed continuously at various rates. The relative rates of these ADME processes determine the time course of the drug in the body, most importantly at the receptor sites that are responsible for the pharmacological action of the drug. 

The processes of both seed formation and fibril extension are dependent on temperature and on peptide concentration, with 37°C being required for establishing equilibrium within 24 h with 30 pM Pi 4o- A full description of the assay system may be found elsewhere [97,117], A 4 h reaction time is typically within the linear portion of the time course. This nucleus-dependent assay detects mainly inhibitors that are substoichiometric with the monomeric peptide, which is present at high concentration. It is relatively insensitive to inhibitors that target the monomeric peptide. Whether the inhibitors interact with the growing end of a seed or with a low abundance conformational form of the p peptide that is competent to add to the seed is difficult to determine at this time. Similar dose-response curves are obtained for Congo Red as an inhibitor with either thioflavin T (ThT) fluorescence or filtration of radioiodinated peptide readouts (Fig. 4) Caveats in the interpretation of both the ThT and radiometric filtration assays for the evaluation of putative inhibitors are discussed elsewhere [97]. 

Changes in the occupancy of the open-channel state of the receptor as a function of time (pA2R (t)) in response to a perturbation of the receptor equilibrium can be used to obtain information about the rates of channel gating and the interaction of dmgs with ion-channel receptors. The system is said to relax towards a new equilibrium. The time course of the relaxation is used to measure rates from the average behavior of many ion channels in a recording, while noise analysis uses the frequency of the moment-to-moment fluctuations in occupancy of the open-channel state at equilibrium to provide information about the rates in the receptor mechanism. 

FIGURE 7.14 Time-course of G-protein-mediated activation of GIRK potassium channels in rabbit sinoatrial node cells, (a). Outward current evoked by a 33-msec, 50-nA iontophoretic pulse of acetylcholine (between arrows), (b). Response of the unclamped cell to an iontophoretic pulse of acetylcholine (ACh). (Record (a) is adapted with permission from Trautwein et al., in Drug Receptors and Their Effectors, Birdsall, N. J. M., Ed., Macmillan, New York, 1980, pp. 5-22 record (b) is adapted with permission from Noma, in Electrophysiology of Single Cardiac Cells, Noble, D. and Powell, T., Eds., Academic Press, San Diego, CA, 1987, pp. 223-246.)... 

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