This tutorial reviews the principles of the concentration — effect relationship for the usual case when drug effects are delayed relative to changes in circulating concentrations. The key processes determining delay are distribution from the circulation to the receptor, binding to the receptor to produce a stimulus and translation of the receptor stimulus into an effect through turnover of physiological mediators. Some clinical outcomes are dependent on the accumulation of drug action which is predictable in terms of basic pharmacokinetic and pharmacodynamic concepts.
Dose-Response Relationship, Drug ; Models, Biological

OBJECTIVETo investigate the effect of the photodynamic therapy (PDT) with the new water-soluble metalloporphyrin compound on human prostate cancer PC-3 cells in vitro and the anticancer mechanism of PDT.

METHODSThe new water-soluble manganese, 5,10,15, 20-tetra (N-methyl4-pyridyl) porphinato (2-) tetraiodide salt, was synthesized. The PC-3 cells were treated with the compound of serial concentrations(0, 0.1, 1, 1.0 micromol/L) followed by irradiation of different dosages of visible light. The techniques of MTT and Annexin-V/propidium iodide double-labeled flow cytometry (FCM) were applied to measuring the inhibitory effect of the compound on the growth activity and apoptosis of the cells.

RESULTSWhen the metalloporphyrin compound concentration was within 10 micromol/L and the irradiation time was within 30 min, the water-soluble metalloporphyrin compound had a significant inhibitory effect on the proliferation of PC-3 cells and induced PC-3 cell apoptosis, and the effects depended greatly on metalloporphyrin concentration and illumination dosages. Higher concentrations and dosages induced the death of the majority of PC-3 cells.

CONCLUSIONThe PDT of the water-soluble metalloporphyrin compound followed by light irradiation has a distinctive killing effect on PC-3 cells in vitro, and the rates of proliferation inhibition and cell apoptosis are correlated with metalloporphyrin concentration and the dosages of light irradiation. The results suggest that the mechanism of metalloporphyrin PDT may be involved with the induction of apoptosis in human prostate cancer cells.

Apoptosis ; drug effects ; radiation effects ; Cell Line, Tumor ; Dose-Response Relationship, Drug ; Dose-Response Relationship, Radiation ; Humans ; Male ; Metalloporphyrins ; pharmacology ; Photochemotherapy ; Prostatic Neoplasms ; pathology

Therapeutic drug monitoring (TDM) is the clinical practice of measuring specific drugs at designated intervals to maintain a constant concentration in a patient's bloodstream, thereby optimizing individual dosage regimens. It is unnecessary to employ TDM for the majority of medications, and it is used mainly for monitoring drugs with narrow therapeutic ranges, drugs with marked pharmacokinetic variability, medications for which target concentrations are difficult to monitor, and drugs known to cause therapeutic and adverse effects. The process of TDM is predicated on the assumption that there is a definable relationship between dose and plasma or blood drug concentration, and between concentration and therapeutic effects. TDM begins when the drug is first prescribed, and involves determining an initial dosage regimen appropriate for the clinical condition and such patient characteristics as age, weight, organ function, and concomitant drug therapy. When interpreting concentration measurements, factors that need to be considered include the sampling time in relation to drug dose, dosage history, patient response, and the desired medicinal targets. The goal of TDM is to use appropriate concentrations of difficult-to-manage medications to optimize clinical outcomes in patients in various clinical situations.
Algorithms ; Dose-Response Relationship, Drug ; Drug Monitoring/*methods/trends ; Forecasting ; Humans ; Patient Compliance ; Pharmacokinetics

House dust mite sensitized asthmatics are advised to practice allergen avoidance. Charcoal pillows are used in Korea with unsubstantiated claims regarding their efficacy in alleviating asthma symptoms. We tested the effects of activated charcoal on breeding of house dust mites in culture. Twenty live adult house dust mites (Dermatophagoides pteronyssinus) were inoculated, 10 replicates, on culture media containing 0%, 1%, 3%, 5%, 10%, and 20% activated charcoal and incubated at 25 degrees C and a relative humidity of 75%. After four weeks, the mean numbers of live house dust mites were 286, 176, 46, 16, 7, and 0 for the 0%, 1%, 3%, 5%, 10%, and 20% charcoal-containing culture media, respectively. Thus, activated charcoal suppresses breeding of house dust mites and offers a new promising method for house dust mite control.
Pyroglyphidae/*drug effects/*growth & development ; *Pesticides ; Dose-Response Relationship, Drug ; Charcoal/*administration & dosage ; Breeding ; Animals

Child ; Dose-Response Relationship, Drug ; Drug Dosage Calculations ; Humans ; Precision Medicine

OBJECTIVETo investigate the effects of the metabolite produced by Trichomonas vaginalis on human sperm motility in vitro.

METHODSTrichomonas vaginalis having been cultured, the culture solution containing metabolite was obtained by removing the protozoa, then diluted into 3 kinds of concentration. Sperm was obtained from 10 healthy fertile men by masturbation and prepared by swim-up technique to produce a spermatozoon solution of high motility. Every sperm sample was divided into 4 groups (A, B, C, D). Unused culture solution was added to Group A as control, and the other 3 groups (B, C, D) were respectively incubated with the above used culture solution at 3 kinds of concentration (1.2 x 10(9)/L, 6 x 10(8)/L, 1.2 x 10(8)/L). Measurements were carried out at 30 s, 1 h, 2 h, 4 h, 6 h by CASA.

RESULTSSperm motility decreased in both Group B and C markedly, and the effects displayed a concentration- and time-dependent manner.

CONCLUSIONThe metabolite of Trichomonas vaginalis can reduce human sperm motility in vitro, and may be one of the causes of infertility.

Animals ; Dose-Response Relationship, Drug ; Humans ; Male ; Sperm Motility ; drug effects ; Time Factors ; Trichomonas vaginalis ; metabolism

Glutamate (Glu) is the major afferent excitatory neurotransmitter in the auditory system, and excessive Glu may play an important role in cochlear dysfunction. It is unclear how excessive Glu plays roles in cochlear dysfunction in cochlear organotypic cultures. In this study neonatal rat cochlear organotypic cultures were prepared, and then the cochlear tissues were incubated with a new medium containing specific concentrations of Glu (0.1, 0.5, 1, 10 or 20 mmol/L) for 24 h, or incubated with the medium containing a concentration of 20 mmol/L Glu for 6, 12, 24 or 72 h, respectively. It was found that when the cochlear tissues were cultured for 24 h, the inner hair cells (IHCs) were damaged at the concentration of 0.5 mmol/L Glu, and with the increases of the concentrations, the injury was gradually aggravated, and 20 mmol/L Glu resulted in the significant loss of IHCs. In the 20 mmol/L Glu groups, the stereocilia bundles were missing or disarrayed on a few IHCs after culture for 6 h and the damage effect was time-dependent. The missing of IHCs was more significant in the basal turn of the cochlea than in the middle turn of the cochlea under the same concentration of Glu exposure. These results suggest that excessive exogenous Glu affects the morphology of IHCs, but not affects the outer hair cells (OHCs) in cochlear organotypic cultures, and the excitotoxic effects are different on IHCs of different parts of the cochlea under the same concentration of Glu exposure.
Animals ; Cochlea ; drug effects ; Dose-Response Relationship, Drug ; Glutamic Acid ; toxicity ; Rats ; Rats, Sprague-Dawley

Dose-effect relationship is an important topic as well as difficulties in clinical studies on Chinese herbal compounds. The relevant concepts of the dose-effect relationship, its features, its backgrounds, directions and roles of clinical studies on the dose-effect relationship of Chinese herbal compounds were discussed in this essay. The current state of clinical studies was introduced. The confronting challenges of clinical studies were also analyzed, thus providing references for the establishment of appropriate clinical research methods in line with Chinese medicine features.
Dose-Response Relationship, Drug ; Drug Combinations ; Drugs, Chinese Herbal ; administration & dosage ; pharmacology ; Humans ; Phytotherapy

The objective was to observe the influence of previously activated psoralens on the proliferation of K562 cells, and to provide laboratory data for its clinical usage. K562 cells were treated separately with previously and late activated psoralens, then their trypan blue exclusion inhibited rates (TBIR), cell proliferation inhibited rates (CPIR) and colony forming inhibited rates (CFIR) after culture were compared. The results showed that previously activated psoralens displayed an inhibiting effect on the proliferation of K562 cells with a dose-effect relationship. There was no obvious difference between previously and late activated psoralens on TBIR, CPIR and CFIR. In order to exert the inhibitive effect of previously activated psoralens, the time of ultraviolet ray exposure should be 10 minutes at least, and longer than 12 hours for inhibiting K562. The inhibitive effect of previously activated psoratens decreased as the time interval from activation to its use was prolonged. The inhibiting effect of previously activated psoralens was strongest within 6 hours after activation. In conclusion, both previously and late activated psoralens show inhibiting effects on the proliferation of K562, which may be able to use an antineoplastic drug in clinic.
Cell Proliferation ; drug effects ; Dose-Response Relationship, Drug ; Furocoumarins ; pharmacology ; Humans ; K562 Cells ; Time Factors

OBJECTIVE: To observe the anticancer mechanism of allicin by observing the inhibitory effect of allicin on human salivary gland carcinoma cell line MEC-1. METHOD: Cell proliferation were measured by MTT assay at different doses and different hours. In the meantime, cell cycle was detected via flow cytometry after different dose incubation with different hours. RESULT: MTT results showed that the inhibitory rates of MEC-1 proliferations were increased in a concentration-and time-dependent manner. Flow cytometry analysis showed percent-age of MEC-1 cells decreased in G0/G1 phase and increased in G2/M. But there was no evident change in S phase. The cells were mainly blocked in M phase, and the inhibitory effect of the allicin on MEC-1 cells increased with the increasing of concentration and time. CONCLUSION Allicin can inhibit the growth of MEC-1 cells in vitro dramatically.
Cell Cycle ; drug effects ; Cell Line, Tumor ; Dose-Response Relationship, Drug ; Humans ; Sulfinic Acids ; pharmacology