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Results for “Repeatability and Reproducibility”

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PubMed2001

The spectrum of circadian blood pressure changes in type I diabetic patients.

BACKGROUND: The objective of the present study was to characterize the spectrum of circadian blood pressure changes in type I diabetes at different stages of nephropathy by using two monitorings in each patient in order to avoid intra-individual variability. PATIENTS AND METHODS: A total of 80 type I diabetic subjects and the same number of age, sex and awake mean blood pressure (BP)-matched controls were included. According to urinary albumin excretion, there were 57 normoalbuminurics, 15 persistent microalbuminurics and eight proteinurics. Two 24 h ambulatory blood pressure monitorings were performed at the same urinary albumin excretion stage in absence of antihypertensive treatment for each diabetic subject and for their respective control. Blood pressure and heart rate averages during 24 h, awake, sleep, and day: night ratio were calculated. RESULTS: Seven of the eight proteinuric subjects were hypertensives, whereas hypertension was absent in the normoalbuminuric and microalbuminuric groups. The intraindividual reproducibility in diabetics showed repeatability coefficients for the 24 h systolic and diastolic pressure of 33 and 42%, respectively. This reproducibility for the day: night ratio was generally worse, 57% for systolic and 59% for diastolic. A progressive increment in the mean ambulatory BP was observed across the three groups of diabetics and the differences in BP observed were most evident during the night-time period. Though no differences in the 24 h circadian pattern were present between the normoalbuminurics and their controls, nocturnal differences were observed, not only in microalbuminurics for systolic BP (P < 0.05), but also in proteinurics for both systolic BP (P < 0.01) as well as diastolic BP (P < 0.05). No differences were observed in heart rate among the diabetic groups. The non-dipping pattern in the two monitorings was observed in 80, 58, 18 and 10% of the proteinurics, microalbuminurics, normoalbuminurics and control groups, respectively. CONCLUSIONS: Persistent abnormal circadian variability seems to be an early and frequent characteristic of type I diabetics with an increased urinary albumin excretion. Although present in some normalbuminuric subjects, the frequency of this abnormality increases as the incipient nephropathy progresses. By the time proteinuria is established, nearly all subjects present the abnormal pattern.

Adolescent↗

PubMed2002

[Multicenter evaluation of a newly developed microdilution test, brothMIC NTM to determine minimum inhibitory concentrations of antimicrobial agents for nontuberculous mycobacteria].

We developed a new broth microdilution susceptibility test for nontuberculous mycobacteria to determine minimum inhibitory concentrations(MICs). The test method utilized air-dried microplates containing serially diluted antimicrobial agents and the modified Middlebrook 7H9 broth. The nine agents tested were rifampicin, isoniazid, ethambutol, streptomycin, kanamycin, levofloxacin, clarithromycin, ethionamide and amikacin. The test plates were reconstituted by inoculation of 0.1 ml of cell suspensions prepared in distilled water by a 1:100 dilution of the 0.5 McFarland suspension. After inoculation, the isolates resulted in incubation at 36 degrees C with clarithromycin at pH 7.4, and with the remaining agents at pH 6.6. The growth endpoints were visually read after 7-day and 10-day incubations for slowly growing nontuberculous mycobacteria, and after 3-day and 5-day incubations for rapidly growing mycobacteria, respectively. The reproducibility was evaluated with the five ATCC reference strains of nontuberculous mycobacteria. Of the 1,287 repeated tests of the four ATCC slowly growing strains(M. avium, M. intracellulare, M. kansasii and M. gordonae), 1,200(93.2%) of the MICs read after 7-day incubation fell within 3 log 2 dilutions. Also, a strain of rapidly growing mycobacteria, M. fortuitum, was repeatedly tested, and the reproducibility was estimated to be 93.3% after 3-day incubation. A total of 728 clinical isolates of nontuberculous mycobacteria comprising 14 species were tested against nine agents. The MICs against nontuberculous mycobacteria distributed in a wide range, and the activities of rifampicin, levofloxacin, clarithromycin were more potent. These results demonstrate this newly developed test method to be a practical, rapid, quantitative means to determine MICs for nontuberculous mycobacteria in clinical laboratories.

Anti-Bacterial Agents↗

PubMed1981

[The reproducibility of the bronchospasmolytic effects of isoprenaline tests repeated after long intervals under ambulatory conditions].

The functional results of 3 bronchospasmolytic tests using 4 puffs of an isoprenaline-spray repeated in large intervals were compared on 104 patients suffering from obstructive lung diseases. The correlation coefficients and the coefficients of determination of the differences of the forced expiration volume in one second before and after the tests showed no good correspondence of the spasmolytic effects. It is to be stated that the dimensions of an improvement of the functional results can not be prognosticated, not even on condition that the functional situation before the test, the inhalant and the dose would be the same on the repeated test. Therefore an actual test using a known effective drug for the control has to be demanded for the investigation of on bronchospasmolytic inhalant.

Forced Expiratory Volume↗

PubMed2005

Characterization of a 2D ion chamber array for the verification of radiotherapy treatments.

In this study we investigated the characteristics of a commercial ion chamber array and its performance in the verification of radiotherapy plans. The device was the 2D Array Seven29 model (PTW, Freiburg, Germany). This is a two-dimensional detector array with 729 ionization chambers uniformly arranged in a 27 x 27 matrix with an active area of 27 x 27 cm(2). The detector short-, medium- and long-term reproducibility have been tested through an extensive set of repeated measurements. Short-term reproducibility was well within 0.2%. Medium- and long-term reproducibility were within 1%, including set-up reproducibility errors and linac output fluctuations. Dose linearity was also assessed. The system response to dose was verified to be linear within the range 2-500 MU. Output factors matched very well pinpoint chamber measurements performed in the same experimental conditions with a maximum local percentage difference of 0.4%. Furthermore, the 2D Array sensitivity to millimetric collimator positional changes and to perturbation effect of irradiated area was tested. The comparison with ion chamber data carried out in water was very satisfying. Finally, measurements of wedge-modulated fields and IMRT beam sequence matched very well ion chamber dose profiles acquired in a water tank. The extensive tests performed in this investigation show that the 2D Array Seven29 is a reliable and accurate dosimeter and that it could be a useful tool for the quality assurance and the verification of radiotherapy plans.

Humans↗

PubMed2003

Automated generation of a four-dimensional model of the liver using warping and mutual information.

The use of mutual information (MI) based alignment to map changes in liver shape and position from exhale to inhale was investigated. Inhale and exhale CT scans were obtained with intravenous contrast for six patients. MI based alignment using thin-plate spine (TPS) warping was performed between each inhale and exhale image set. An expert radiation oncologist identified corresponding vessel bifurcations on the exhale and inhale CT image and the transformation for identified points was determined. This transformation was then used to determine the accuracy of the MI based alignment. The reproducibility of the vessel bifurcation identification was measured through repeat blinded vessel bifurcation identification. Reproducibility [standard deviation (SD)] in the L/R, A/P, and I/S directions was 0.11, 0.09, and 0.14 cm, respectively. The average absolute difference between the transformation obtained using MI based alignment and the vessel bifurcation in the L/R, A/P, and I/S directions was 0.13 cm (SD=0.10 cm), 0.15 cm (SD=0.12 cm), and 0.15 cm (SD-0.14 cm), respectively. These values are comparable to the reproducibility of bifurcation identification, indicating that MI based alignment using TPS warping is accurate to within measurement error and is a reliable tool to aid in describing deformation that the liver undergoes from the exhale to inhale state.

Algorithms↗

PubMed1977

Reliability of the PSE (ninth edition) used in a population study.

A random sample of 237 women in a south-east London area were seen by non-medical interviewers, trained to use a standard technique (the Present State Examination) to elicit and record psychiatric symptoms. Ninety-five were interviewed a second time by psychiatrists, who also rated audiotape recordings. The reproducibility of the techniques is adequate though not as high, in some respects, as that obtained from out-patient or in-patient samples. This is true at the level of symptom, syndrome, total score, and index of definition of psychiatric disorder. It is concluded that non-medical interviewers can obtain as high reproducibility as psychiatrists on most of the non-psychotic sections of the PSE if they have appropriate training. Repeatability is lower than reproducibility, partly due to fluctuations in clinical condition, partly to environmental changes between interviews, and partly to differential responses to medical and non-medical interviews. Over a short period of time, such as a week, repeatability is satisfactory.

Adolescent↗

PubMed2001

Population structure and genetic diversity of Botrychium pumicola (Ophioglossaceae) based on inter-simple sequence repeats (ISSR).

Species of Botrychium reproduce by spores that form subterranean gametophytes and a few, like B. pumicola, also reproduce asexually with subterranean sporophytic gemmae. The goal of this study was to examine the genetic diversity of B. pumicola populations and to better understand the role of gemmae. Ninety-nine individuals from three monitored populations were sampled. The technique of inter-simple sequence repeats (ISSR) produced 15 polymorphic loci and identified 71 ISSR genotypes. Sixteen of the ISSR genotypes were shared by more that one individual in a population, representing potential clones. Ten of the 16 shared genotypes were not limited to clusters of plants (groups of plants growing from the same point). The ten potential clones were disjunct (separated by other genotypes) and not in patches as might be expected for an underground propagule. There is a high probability that these shared genotypes arose from independent sexual events suggesting they were not clones. These results suggest that the long-distance dispersal of gemmae is at best a rare event.

Journal Article↗

PubMed1999

Quantitative changes in cytological molecular markers during primary medical treatment of breast cancer: a pilot study.

AIM: To quantify the changes in biological molecular markers during primary medical treatment in patients with operable breast cancer and to assess their possible relationship with response to treatment. METHODS: The treatment group consisted of 31 patients with operable breast carcinomas, median age 57 years (range 41-67), treated with four 3-weekly cycles of chemotherapy with Mitoxantrone, methotrexate (+/- mitomycin C), and tamoxifen before surgery. Fine needle aspiration (FNA) was used to obtain samples from patients prior to and at 10 or 21 days post-treatment. The following molecular markers were assessed: estrogen receptor (ER), progesterone receptor (PgR), p53, Bcl-2, and Ki67 measured by immunocytochemistry, and ploidy and S-phase fraction (SPF) by flow cytometry. To evaluate the reproducibility of the technique, repeat FNA was performed in a separate non-treatment control group of 20 patients and the same molecular markers assessed, two weeks after the first sample with no intervening treatment. RESULTS: The non-treatment control group showed a high reproducibility for the measurement of molecular markers from repeat FNA. In the treatment group there was a non-significant reduction in SPF and a significant reduction (p = 0.005) in Ki67. Patients who responded to neoadjuvant therapy were more likely to have a reduction in these two markers than those who failed to respond. Similarly, a reduction in ER scores was observed between the first and second samples (p = 0.04). For PgR, the change between the first and second samples was not significant although there was a significant difference between responders and non-responders (p = 0.03). All nine patients with an increase in PgR were responders. No significant changes in p53 or Bcl-2 were observed during treatment. CONCLUSION: Molecular markers can be adequately measured from FNA samples prior to and during neoadjuvant therapy. Changes in cellular proliferation and hormone receptors have been shown that may be related to tumour response. These relationships should be assessed in a larger cohort of patients.

Adult↗

PubMed1988

Subacute administration of a TRH analogue (RX77368) in motorneuron disease: an open study.

Sixteen patients with motor neuron disease received RX77368, a TRH analogue, IV, repeatedly over 1-12 weeks (median 2 weeks). Slight to moderate improvement in bulbar function, particularly speech, was reproduced or persisted with repeated infusions in 8 of 12 responders over a median of 18 days (range 14-90) during the period of study. Cramps (5/9) and spasticity (5/8) improved for a median of 14 days (range 7-35) and 7 days (range 2-14) respectively. The highest benefit/side effect ratio was seen with 0.2 mg/kg (0.15 mg/kg in those with severe bulbar palsy) every 3-4 days. Long term studies with this analogue in MND are indicated.

Activities of Daily Living↗

PubMed2001

Instability of a (CGG)98 repeat in the Fmr1 promoter.

Fragile X syndrome is one of 14 trinucleotide repeat diseases. It arises due to expansion of a CGG repeat which is present in the 5'-untranslated region of the FMR1 gene, disruption of which leads to mental retardation. The mechanisms involved in trinucleotide repeat expansion are poorly understood and to date, transgenic mouse models containing transgenic expanded CGG repeats have failed to reproduce the instability seen in humans. As both cis-acting factors and the genomic context of the CGG repeat are thought to play a role in expansion, we have now generated a knock-in mouse Fmr1 gene in which the murine (CGG)8 repeat has been exchanged with a human (CGG)98 repeat. Unlike other CGG transgenic models, this model shows moderate CGG repeat instability upon both in maternal and paternal transmission. This model will now enable us to study the timing and the mechanism of repeat expansion in mice.

Alleles↗

PubMed1997

A self-administered questionnaire for assessment of symptoms and function of the shoulder.

A self-administered questionnaire was designed to assess the severity of symptoms related to and the functional status of the shoulder. It includes domains of global assessment, pain, daily activities, recreational and athletic activities, work, satisfaction, and areas for improvement. Each domain is graded separately and is weighted to arrive at the total score. The over-all scale and each domain were prospectively tested for validity, reliability, and responsiveness to clinical change. One hundred patients who were seen for evaluation of the shoulder were enrolled in the study. The validity of the scale was demonstrated by moderate-to-high correlation of the domains and individual questions of the Shoulder Rating Questionnaire with those of the Arthritis Impact Measurement Scales 2. Validity was supported further by significant correlation of the scores in each domain with the level of satisfaction in that domain and by significantly lower scores in domains that patients selected as areas important for improvement. The over-all scale and each domain were internally consistent (Cronbach alpha, 0.71 to 0.90). Reproducibility was evaluated by repeated administration of the questionnaire after a mean of three days to forty patients whose condition was clinically stable. Reproducibility of the over-all questionnaire and individual domains was excellent (Spearman-Brown index, 0.94 to 0.98). Individual questions were reproducible, with a weighted kappa value of more than 0.7 for each. Responsiveness was evaluated by comparison of the preoperative and postoperative scores of thirty patients who had a satisfactory result one year after an operation on the shoulder. The over-all Shoulder Rating Questionnaire and each domain were responsive to clinical change as demonstrated by favorable standardized response means (range, 1.1 to 1.9) and indices of responsiveness (range, 1.1 to 2.0). Similar analysis performed for individual diagnostic groups supported the validity, reliability, and responsiveness of the questionnaire in each group. The self-administered shoulder questionnaire was found to be valid, reliable, and responsive to clinical change. These qualities should make it a useful instrument for the prospective assessment of the outcome of treatment of disorders related to the shoulder.

Activities of Daily Living↗

PubMed1999

A low-cost, portable system for the assessment of the postural response of wheelchair users to perturbations.

Maintaining seated postural stability presents a serious challenge to wheelchair users in vehicles, even during normal driving conditions. The purpose of this research was to develop a system for the study of seated postural control in response to perturbations similar to those that might be experienced during vehicle turning and braking. A servo-controlled tilt platform was constructed to provide a low-cost, small, and easily transportable device for generating precise and repeatable perturbations. Tilt platform operation was examined for accuracy and reproducibility of a desired perturbation. Repeatability was high with a mean signal-to-noise ratio (SNR) of 45.4 for a given perturbation measured across 11 subjects. An initial comparison of stability results obtained on the tilt platform and in a vehicle showed a correspondence, although differences were apparent. The tilt platform has been used successfully to assess balance in spinal cord-injured subjects and to test wheelchair securement systems.

Acceleration↗

PubMed2005

Assessment of atrial regional and global electromechanical function by tissue velocity echocardiography: a feasibility study on healthy individuals.

BACKGROUND: The appropriate evaluation of atrial electrical function is only possible by means of invasive electrophysiology techniques, which are expensive and therefore not suitable for widespread use. Mechanical atrial function is mainly determined from atrial volumes and volume-derived indices that are load-dependent, time-consuming and difficult to reproduce because they are observer-dependent. AIMS: To assess the feasibility of tissue velocity echocardiography (TVE) to evaluate atrial electromechanical function in young, healthy volunteers. SUBJECTS AND METHODS: We studied 37 healthy individuals: 28 men and nine women with a mean age of 29 years (range 20-47). Standard two-dimensional (2-D) and Doppler echocardiograms with superimposed TVE images were performed. Standard echocardiographic images were digitized during three consecutive cardiac cycles in cine-loop format for off-line analysis. Several indices of regional atrial electrical and mechanical function were derived from both 2-D and TVE modalities. RESULTS: Some TVE-derived variables indirectly reflected the atrial electrical activation that follows the known activation process as revealed by invasive electrophysiology. Regionally, the atrium shows an upward movement of its walls at the region near the atrio-ventricular ring with a reduction of this movement towards the upper levels of the atrial walls. The atrial mechanical function as assessed by several TVE-derived indices was quite similar in all left atrium (LA) walls. However, all such indices were higher in the right (RA) than the LA. There were no correlations between the 2-D- and TVE-derived variables expressing atrial mechanical function. Values of measurement error and repeatability were good for atrial mechanical function, but only acceptable for atrial electrical function. CONCLUSION: TVE may provide a simple, easy to obtain, reproducible, repeatable and potentially clinically useful tool for quantifying atrial electromechanical function.

Atrial Function↗

PubMed2005

Mechanical properties of the human patellar tendon, in vivo.

BACKGROUND: Mechanical properties of the human patellar tendon are largely based on cadaver studies, which may not necessarily be applicable to the human patellar tendon, in vivo. While ultrasonography is an attractive non-invasive method for studying human, in vivo, muscle-tendon behaviour, it has mostly been used to examine Achilles tendon properties. We examine the accuracy of human patellar tendon elongation, in vivo, and its within-day and between-day reproducibility. METHODS: Subjects performed four maximal 10-s ramp isometric knee extension trials to examine within-day reproducibility, and the procedure was repeated on a separate day to assess between-day reproducibility. Continuous and simultaneous ultrasonography based measurement of both tibial and patellar movement together with patellar tendon force yielded mechanical estimates. RESULTS: Longitudinal tibial displacement corresponded to 45 (SEM 8) % of the overall tibia-patella displacement. For within-day reproducibility there was no difference between trials for stiffness [trial a, 4334 (SEM 562) N/mm; trial b, 4273 (SEM 533) N/mm], strain [trial a, 6.9 (SEM 0.6) %; trial b, 6.8 (SEM 0.7) %] or elastic modulus [trial a, 1.09 (SEM 0.12) GPa; trial b, 1.09 (SEM 0.10) GPa]. The within day correlation coefficient and typical error were 0.95 and 9.9% for stiffness, 0.97 and 5.5% for strain, and 0.94 and 9.4% for elastic modulus. The corresponding values for between days were 0.94 and 8.7% for stiffness, 0.98 and 3.7% for strain, and 0.86 and 9.6% for elastic modulus. INTERPRETATION: The present methodology of assessing human patellar tendon elongation, strain and stiffness, in vivo, is accurate and reproducible which permits its use in future investigations of patellar tendon biomechanics and the potential effects of various interventions.

Adult↗

PubMed2005

Coronary calcium measurements: effect of CT scanner type and calcium measure on rescan reproducibility--MESA study.

PURPOSE: To evaluate the effect of scanner type and calcium measure on the reproducibility of calcium measurements. MATERIALS AND METHODS: This investigation was approved by the institutional review boards of each study site and by the Institutional Review Board of the Los Angeles Biomedical Research Institute. Informed consent for scanning and participation was obtained from all participants. The study was Health Insurance Portability and Accountability Act compliant. The Multi-Ethnic Study of Atherosclerosis (MESA) is a multicenter observational study of 6814 participants undergoing demographic, risk factor, and subclinical disease evaluations. Coronary artery calcium was measured by using duplicate CT scans. Three study centers used electron-beam computed tomography (CT), and three used multi-detector row CT. Coronary artery calcium was detected in 3355 participants. Three calcium measurement methods-Agatston score, calcium volume, and interpolated volume score-were evaluated. Mean absolute differences between calcium measures on scans 1 and 2, excluding cases for which both scans had a measure of zero, was modeled by using linear regression to compare reproducibility between scanner types. A repeated measures analysis of variance test was used to compare reproducibility across calcium measures, with mean percentage absolute difference as the outcome measure. Rescan reproducibility in relation to misregistrations, noise, and motion artifacts was also examined. Variables were log transformed to create a more normal distribution. RESULTS: Concordance for presence of calcium between duplicate scans was high and similar for both electron-beam and multi-detector row CT (96%, kappa = 0.92). Mean absolute difference between calcium scores for the two scans was 15.8 for electron-beam and 16.9 for multi-detector row CT scanners (P = .06). Mean relative differences were 20.1 for Agatston score, 18.3 for calcium volume, and 18.3 for interpolated volume score (P < .01). Reproducibility was lower for scans with versus those without image misregistrations or motion artifacts (P < .01 for both). CONCLUSION: Electron-beam and multi-detector row CT scanners have equivalent reproducibility for measuring coronary artery calcium. Calcium volumes and interpolated volume scores are slightly more reproducible than Agatston scores. Reproducibility is lower for scans with misregistrations or motion artifacts.

Calcinosis↗

PubMed2005

An in-vitro and in-vivo methodology study of alveolar bone measurement using extra-oral radiographic alignment apparatus, Image Pro-Plus software and a subtraction programme.

OBJECTIVES: (a) To validate a method for acquiring reproducible radiographic images and repeatable measurements of digital images. (b) To investigate the clinical and radiographic changes following periodontal surgery and in a periodontally healthy control group. METHODS: In-vitro study. Sixteen dried human skulls had replicate intra-oral radiographs taken using an extra-oral alignment apparatus under simulated clinical conditions, and measurements were made on the images using Image Pro-Plus analysis software. In-vivo study. Seven subjects, aged 38-63 years with chronic periodontitis, were treated using replaced flap surgery. Nine patients with healthy periodontal tissues were recruited as a control group. Clinical measurements and radiographs were taken pre-surgery and 6 months afterwards, and at the same interval for untreated healthy controls using the alignment apparatus. Radiographs were analysed using Image Pro-Plus and subtraction radiography. RESULTS: Radiographs had a high degree of reliability (ICC 0.98-0.99) for the in-vitro study and intra-operator repeatability of measurements was high (ICC 0.65-0.99) for the in-vivo study. Over this interval there were both significant clinical improvements and in bone gain within infra-bony defects on radiographs. Subtracted images showed that out of 17 surgically treated sites, 13 showed evidence of bone gain, one showed no change, two showed bone loss and one could not be interpreted due to poor alignment. Overall there were no significant clinical or radiographic changes in the control group. CONCLUSIONS: Radiographic images were highly reproducible. Measurements had a high degree of repeatability. The methods used allowed accurate quantitative and qualitative measurement of change in alveolar bone. This technique would allow accurate measurement of any changes in alveolar bone levels in patients with periodontal disease.

Adult↗

PubMed1992

Frequency versus time domain analysis of signal-averaged electrocardiograms. I. Reproducibility of the results.

Three repeated signal-averaged electrocardiographic (ECG) recordings were made in 40 subjects (15 healthy volunteers, 10 patients with ventricular tachycardia without apparent heart disease and 15 patients with ventricular tachycardia after myocardial infarction). In each subject, the three recordings were made within 25 min. The recordings were subsequently analyzed by 1) the conventional time domain method of signal-averaged ECG analysis with use of filter settings of 25 to 250 Hz and 40 to 250 Hz, 2) a spectral analysis method computing the energy area within the spectral boundaries of 40 to 140 Hz and the ratio between the energies of areas within the boundaries 40 to 140 Hz and 0 to 40 Hz, and 3) spectral temporal mapping computing the "normality factor." The study compared the reproducibility of these three approaches to the analysis of signal-averaged ECGs. First, the reproducibility of the diagnostic conclusions (that is, of the diagnosis of late potentials) was compared for the time domain method and for spectral temporal mapping. Second, the reproducibility of the numeric values of individual indexes provided by different methods was compared for all methods by computing the ratios between standard deviations of measurements in individual patients and standard deviation of all measurements. The reproducibility of diagnostic conclusions was significantly higher for the time domain method than for spectral temporal mapping (p less than 0.05, sign test). The numeric reproducibility of the normality factors produced by spectral temporal mapping was significantly lower than the numeric reproducibility of the values of all indexes provided by time domain, spectral area and spectral area ratio methods (p less than 0.05 to 0.00005, Wilcoxon tests). Spectral temporal mapping was the least reproducible method for the analysis of signal-averaged ECGs.

Adult↗

PubMed2006

A reduced mathematical model of the acute inflammatory response II. Capturing scenarios of repeated endotoxin administration.

Bacterial lipopolysaccharide (LPS; endotoxin) is a potent immunostimulant that can induce an acute inflammatory response comparable to a bacterial infection. Experimental observations demonstrate that this biological response can be either blunted (tolerance) or augmented (potentiation) with repeated administration of endotoxin. Both phenomena are of clinical relevance. We show that a four-dimensional differential equation model of this response reproduces many scenarios involving repeated endotoxin administration. In particular, the model can display both tolerance and potentiation from a single parameter set, under different administration scenarios. The key determinants of the outcome of our simulations are the relative time-scales of model components. These findings support the hypothesis that endotoxin tolerance and other related phenomena can be considered as dynamic manifestations of a unified acute inflammatory response, and offer specific predictions related to the dynamics of this response to endotoxin.

Acute Disease↗