scholarly journals The population dynamics of antimicrobial chemotherapy.

1997 ◽  
Vol 41 (2) ◽  
pp. 363-373 ◽  
Author(s):  
M Lipsitch ◽  
B R Levin
Keyword(s):  
Population Dynamics ◽  
Treatment Efficacy ◽  
Experimental Studies ◽  
Resistant Mutant ◽  
Resistant Bacteria ◽  
Multiple Drug ◽  
Antibiotic Exposure ◽  
Treatment Protocols ◽  
Emergence Of Resistance ◽  
The Relationship

We present and analyze a series of mathematical models for the emergence of resistance during antibiotic treatment of an infected host. The models consider the population dynamics of antibiotic-sensitive and -resistant bacteria during the course of treatment and addresses the following problems: (i) the probability of obtaining a resistant mutant during the course of treatment as a function of antibiotic exposure; (ii) the conditions under which high, infrequent doses of an antibiotic are predicted to succeed in preventing the emergence of resistance; (iii) the conditions for the success of multiple drug treatment in suppressing the emergence of resistance and the relationship between antibiotic synergism and suppression of resistance; and (iv) the conditions under which nonadherence to the prescribed treatment regimen is predicted to result in treatment failure due to resistance. We analyze the predictions of the model for interpreting and extrapolating existing experimental studies of treatment efficacy and for optimizing treatment protocols to prevent the emergence of resistance.

scholarly journals Antimicrobial Resistance within Host: A Population Dynamics View

2014 ◽  
Vol 2014 ◽  
pp. 1-5
Author(s):  
Chunji Huang ◽  
Aijun Fan
Keyword(s):  
Population Dynamics ◽  
Antimicrobial Resistance ◽  
Mathematical Analysis ◽  
Resistant Strain ◽  
High Strength ◽  
Susceptible Strain ◽  
Antibiotic Exposure ◽  
Treatment And Prevention ◽  
The Relationship

To study the relationship between antimicrobial resistance and the concentration of antibiotics, a competitive population dynamical model is proposed between the susceptible strain and the resistant strain with antibiotic exposure. The strict mathematical analysis is performed, and the results indicate that long-term high strength antibiotic treatment and prevention can induce the extinction of susceptible strain. Thus, the prescribed dose of antibiotics must be strictly controlled during the treatment and prevention of the infections in clinics.

scholarly journals Antibiotic Resistance in the Intensive Care Unit: A Primer in Bacteriology

2005 ◽  
Vol 33 (2) ◽  
pp. 188-195
Author(s):  
J. Iredell ◽  
J. Lipman
Keyword(s):  
Intensive Care ◽  
Selective Decontamination ◽  
Resistant Bacteria ◽  
Care Community ◽  
Development Of Resistance ◽  
Management Approaches ◽  
Antibiotic Cycling ◽  
Relationship Of ◽  
Emergence Of Resistance ◽  
The Relationship

The clinical use of potent, well-tolerated, broad-spectrum antibiotics has been paralleled by the development of resistance in bacteria, and the prevalence of highly resistant bacteria in some intensive care units is despairingly commonplace. The intensive care community faces the realistic prospect of untreatable nosocomial infections and should be searching for new approaches to diagnose and manage resistant bacteria. In this review, we discuss some of the relevant underlying biology, with a particular focus on genetic transfer vehicles and the relationship of selection pressure to their movements. It is an attempt to demystify the relevant language and concepts for the anaesthetist and intensivist, to explain some of the reasons for the emergence of resistance in bacteria, and to provide a contextual basis for discussion of management approaches such as selective decontamination and antibiotic cycling.

scholarly journals Population Dynamics of Antibiotic Treatment: a Mathematical Model and Hypotheses for Time-Kill and Continuous-Culture Experiments

2010 ◽  
Vol 54 (8) ◽  
pp. 3414-3426 ◽  
Author(s):  
Bruce R. Levin ◽  
Klas I. Udekwu
Keyword(s):  
Mathematical Model ◽  
Population Dynamics ◽  
Continuous Culture ◽  
Antibiotic Treatment ◽  
Target Population ◽  
Treatment Protocols ◽  
Model Combining ◽  
Time Kill ◽  
The Mathematical Model ◽  
The Relationship

ABSTRACT The objectives of the study were to develop a quantitative framework for generating hypotheses for and interpreting the results of time-kill and continuous-culture experiments designed to evaluate the efficacy of antibiotics and to relate the results of these experiments to MIC data. A mathematical model combining the pharmacodynamics (PD) of antibiotics with the population dynamics of bacteria exposed to these drugs in batch and continuous cultures was developed, and its properties were analyzed numerically (using computer simulations). These models incorporate details of (i) the functional form of the relationship between the concentrations of the antibiotics and rates of kill, (ii) the density of the target population of bacteria, (iii) the growth rate of the bacteria, (iv) byproduct resources generated from dead bacteria, (v) antibiotic-refractory subpopulations, persistence, and wall growth (biofilms), and (vi) density-independent and -dependent decay in antibiotic concentrations. Each of the factors noted above can profoundly affect the efficacy of antibiotics. Consequently, if the traditional (CLSI) MICs represent the sole pharmacodynamic parameter, PK/PD indices can fail to predict the efficacy of antibiotic treatment protocols. More comprehensive pharmacodynamic data obtained with time-kill and continuous-culture experiments would improve the predictive value of these indices. The mathematical model developed here can facilitate the design and interpretation of these experiments. The validity of the assumptions behind the construction of these models and the predictions (hypotheses) generated from the analysis of their properties can be tested experimentally. These hypotheses are presented, suggestions are made about how they can be tested, and the existing statuses of these tests are briefly discussed.

scholarly journals Correlation between Fecal Concentrations of Ciprofloxacin and Fecal Counts of Resistant Enterobacteriaceae in Piglets Treated with Ciprofloxacin: toward New Means To Control the Spread of Resistance?

2012 ◽  
Vol 56 (9) ◽  
pp. 4973-4975 ◽  
Author(s):  
Thu Thuy Nguyen ◽  
Elisabeth Chachaty ◽  
Clarisse Huy ◽  
Carole Cambier ◽  
Jean de Gunzburg ◽  
...  
Keyword(s):  
Body Weight ◽  
Resistant Bacteria ◽  
Fecal Flora ◽  
Content Type ◽  
Emergence Of Resistance ◽  
The Relationship

ABSTRACTWe assessed in a piglet model the relationship between fecal ciprofloxacin concentrations and ciprofloxacin-resistantEnterobacteriaceaecounts. Twenty-nine piglets were orally treated with placebo or with 1.5 or 15 mg ciprofloxacin/kg of body weight/day from day 1 (D1) to D5. Areas under the curve (AUC) of concentrations increased sharply with dose and correlated positively with AUC of resistant bacteria log counts between D1 and D9. Removing residual colonic quinolones could help to control the emergence of resistance in fecal flora.

Establishing a Group Educational Session for Hyperacusis Patients

2019 ◽  
Vol 28 (2) ◽  
pp. 245-250
Author(s):  
Ann E. Perreau ◽  
Richard S. Tyler ◽  
Patricia C. Mancini ◽  
Shelley Witt ◽  
Mohamed Salah Elgandy
Keyword(s):  
Therapeutic Process ◽  
Treatment Options ◽  
Clinical Group ◽  
Education Session ◽  
Group Approach ◽  
Treatment Protocols ◽  
Educational Session ◽  
Evidence Based Treatment ◽  
Relationship Of ◽  
The Relationship

Purpose Audiologists should be treating hyperacusis patients. However, it can be difficult to know where to begin because treatment protocols and evidence-based treatment studies are lacking. A good place to start in any tinnitus and hyperacusis clinic is to incorporate a group educational session. Method Here, we outline our approach to establishing a hyperacusis group educational session that includes specific aspects of getting to know each patient to best meet their needs, understanding the problems associated with hyperacusis, explaining the auditory system and the relationship of hyperacusis to hearing loss and tinnitus, describing the influence of hyperacusis on daily life, and introducing treatment options. Subjective responses from 11 adults with hyperacusis, who participated in a recent clinical group education session, were discussed to illustrate examples from actual patients. Conclusions Due to the devastating nature of hyperacusis, patients need to be reassured that they are not alone and that they can rely on audiologists to provide support and guidance. A group approach can facilitate the therapeutic process by connecting patients with others who are also affected by hyperacusis, and by educating patients and significant others on hyperacusis and its treatment options. Supplemental Material https://doi.org/10.23641/asha.8121197

Potential Role of Inflammation in Associations between Particulate Matter and Heart Failure

2018 ◽  
Vol 24 (3) ◽  
pp. 341-358 ◽  
Author(s):  
Xiaotong Ji ◽  
Yingying Zhang ◽  
Guangke Li ◽  
Nan Sang
Keyword(s):  
Heart Failure ◽  
Particulate Matter ◽  
Inflammatory Response ◽  
Heart Diseases ◽  
Experimental Studies ◽  
Epidemiological Studies ◽  
Inflammatory Mechanism ◽  
High Concentrations ◽  
Future Work ◽  
The Relationship

Recently, numerous studies have found that particulate matter (PM) exposure is correlated with increased hospitalization and mortality from heart failure (HF). In addition to problems with circulation, HF patients often display high expression of cytokines in the failing heart. Thus, as a recurring heart problem, HF is thought to be a disorder characterized in part by the inflammatory response. In this review, we intend to discuss the relationship between PM exposure and HF that is based on inflammatory mechanism and to provide a comprehensive, updated evaluation of the related studies. Epidemiological studies on PM-induced heart diseases are focused on high concentrations of PM, high pollutant load exposure in winter, or susceptible groups with heart diseases, etc. Furthermore, it appears that the relationship between fine or ultrafine PM and HF is stronger than that between HF and coarse PM. However, fewer studies paid attention to PM components. As for experimental studies, it is worth noting that coarse PM may indirectly promote the inflammatory response in the heart through systematic circulation of cytokines produced primarily in the lungs, while ultrafine PM and its components can enter circulation and further induce inflammation directly in the heart. In terms of PM exposure and enhanced inflammation during the pathogenesis of HF, this article reviews the following mechanisms: hemodynamics, oxidative stress, Toll-like receptors (TLRs) and epigenetic regulation. However, many problems are still unsolved, and future work will be needed to clarify the complex biologic mechanisms and to identify the specific components of PM responsible for adverse effects on heart health.

scholarly journals Experimental studies on the transformation from firn to ice in the wet-snow zone of temperate glaciers

1997 ◽  
Vol 24 ◽  
pp. 181-185 ◽  
Author(s):  
Katsuhisa Kawashima ◽  
Tomomi Yamada
Keyword(s):  
Experimental Studies ◽  
Ice Formation ◽  
Compression Tests ◽  
Densification Rate ◽  
Overburden Pressure ◽  
Proportionality Constant ◽  
Wet Snow ◽  
Water Saturated ◽  
The Relationship ◽  
Good Agreement

The densification of water-saturated firn, which had formed just above the firn-ice transition in the wet-snow zone of temperate glaciers, was investigated by compression tests under pressures ranging from 0.036 to 0.173 MPa, with special reference to the relationship between densification rate, time and pressure. At each test, the logarithm of the densification rate was proportional to the logarithm of the time, and its proportionality constant increased exponentially with increasing pressure. The time necessary for ice formation in the firn aquifer was calculated using the empirical formula obtained from the tests. Consequently, the necessary time decreased exponentially as the pressure increased, which shows that the transformation from firn in ice can be completed within the period when the firn aquifer exists, if the overburden pressure acting on the water-saturated firn is above 0.12–0.14 MPa. This critical value of pressure was in good agreement with the overburden pressure obtained from depth–density curves of temperate glaciers. It was concluded that the depth of firn–ice transition was self-balanced by the overburden pressure to result in the concentration between 20 and 30 m.

scholarly journals Application of intelligent orienteering based on Internet of things

2020 ◽  
Vol 2020 (1) ◽  
Author(s):  
Donghui Zhang ◽  
Ruijie Liu
Keyword(s):  
Internet Of Things ◽  
Network Architecture ◽  
Emergency Services ◽  
Simulation Experiment ◽  
Experimental Studies ◽  
Signal Stability ◽  
Anchor Nodes ◽  
Set Up ◽  
The Relationship ◽  
The Internet Of Things

Abstract Orienteering has gradually changed from a professional sport to a civilian sport. Especially in recent years, orienteering has been widely popularized. Many colleges and universities in China have also set up this course. With the improvement of people’s living conditions, orienteering has really become a leisure sport in modern people’s life. The reduced difficulty of sports enables more people to participate, but it also exposes a series of problems. As the existing positioning technology is relatively backward, the progress in personnel tracking, emergency services, and other aspects is slow. To solve these problems, a new intelligent orienteering application system is developed based on the Internet of things. ZigBee network architecture is adopted in the system. ZigBee is the mainstream scheme in the current wireless sensor network technology, which has many advantages such as convenient carrying, low power consumption, and signal stability. Due to the complex communication environment in mobile signal, the collected information is processed by signal amplification and signal anti-interference technology. By adding anti-interference devices, video isolators and other devices, the signal is guaranteed to the maximum extent. In order to verify the actual effect of this system, through a number of experimental studies including the relationship between error and traffic radius and the relationship between coverage and the number of anchor nodes, the data shows that the scheme studied in this paper has a greater improvement in comprehensive performance than the traditional scheme, significantly improving the accuracy and coverage. Especially the coverage is close to 100% in the simulation experiment. This research has achieved good results and can be widely used in orienteering training and competition.

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