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PubMed2003

European Consensus Lupus Activity Measurement is sensitive to change in disease activity in childhood-onset systemic lupus erythematosus.

OBJECTIVES: To evaluate the European Consensus Lupus Activity Measurement (ECLAM) for responsiveness to change in disease activity when used in childhood-onset systemic lupus erythematosus (cSLE). To confirm the construct validity and to characterize the measurement properties of the ECLAM by assessing its ability to predict damage and steroid requirements. METHODS: The disease courses of 66 newly diagnosed cSLE patients were reviewed. The ECLAM and Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) were scored for all clinic visits and hospitalizations. Damage was assessed at the end of the followup period using the Systemic Lupus International Collaboration Clinics/American College of Rheumatology Damage Index. Disease activity at the time of diagnosis, 6 months after diagnosis, at the time of first flare, and 6 months after first flare was used to estimate responsiveness of the measures. Responsiveness was measured by the effect size, the effect size index, the standardized response mean, and the relative efficiency index (REI). The measurement properties of the ECLAM and SLEDAI over time were examined by comparing the ability of both measures to predict damage and oral steroid requirement. RESULTS: The ECLAM and SLEDAI are both responsive to change in disease activity irrespective of the statistic used. The ECLAM is more sensitive than the SLEDAI using the REI (all >1.9). Cumulative disease activity as measured by the SLEDAI or the ECLAM are important predictors of damage. There are no statistically important differences between the 2 measures with regard to their ability to predict steroid requirements. CONCLUSIONS: The ECLAM has construct validity in cSLE and, like the SLEDAI, is highly sensitive to clinically important change in disease activity. The ECLAM may be more responsive. The quantitative properties of the 2 measures are very similar. The SLEDAI likely remains the preferable disease activity measure for cSLE given its overall measurement properties and ease of use.

Administration, Oral↗
PubMed2001

Contingency valuation and preferences of health states associated with side effects of antipsychotic medications in schizophrenia.

The purpose of this study was to investigate the construct validity and the test-retest reliability of the willingness to pay (WTP) method for estimating health state preferences associated with side effects of antipsychotic medication. Ninety-six schizophrenia patients on antipsychotics were asked (1) how much they would be willing to pay to get rid of side effects with 100 percent probability, (2) a standard gamble (SG) question measuring utilities of patient's health state associated with side effects, and (3) their WTP to get rid of side effects based on the utility found with SG. Patients were divided into three groups based on severity of side effects. There was a significant difference between side effect severity groups for (1) the utility associated with side effects (Kruskal-Wallis [K-W] chi-square = 8.48, p = 0.014), and (2) their WTP to get rid of side effects with either 100 percent probability (K-W chi-square = 14.32,p = 0.001) or based on the utility associated with side effects (K-W chi-square = 5.96, p = 0.051). There was a significant correlation between utility and the WTP based on utility (Spearman r = -0.42, p = 0.003). Because of a wide variation in side effects at the 1-month interval, we were unable to assess the test-retest reliability of SG and WTP. Our results suggest that WTP has some construct validity in valuating and measuring preferences of health states associated with side effects of antipsychotics in schizophrenia.

Adult↗
PubMed1998

The factor structure of the SF-36 Health Survey in 10 countries: results from the IQOLA Project. International Quality of Life Assessment.

Studies of the factor structure of the SF-36 Health Survey are an important step in its construct validation. Its structure is also the psychometric basis for scoring physical and mental health summary scales, which are proving useful in simplifying and interpreting statistical analyses. To test the generalizability of the SF-36 factor structure, product-moment correlations among the eight SF-36 Health Survey scales were estimated for representative samples of general populations in each of 10 countries. Matrices were independently factor analyzed using identical methods to test for hypothesized physical and mental health components, and results were compared with those published for the United States. Following simple orthogonal rotation of two principal components, they were easily interpreted as dimensions of physical and mental health in all countries. These components accounted for 76% to 85% of the reliable variance in scale scores across nine European countries, in comparison with 82% in the United States. Similar patterns of correlations between the eight scales and the components were observed across all countries and across age and gender subgroups within each country. Correlations with the physical component were highest (0.64 to 0.86) for the Physical Functioning, Role Physical, and Bodily Pain scales, whereas the Mental Health, Role Emotional, and Social Functioning scales correlated highest (0.62 to 0.91) with the mental component. Secondary correlations for both clusters of scales were much lower. Scales measuring General Health and Vitality correlated moderately with both physical and mental health components. These results support the construct validity of the SF-36 translations and the scoring of physical and mental health components in all countries studied.

Cross-Cultural Comparison↗
PubMed1998

Comparison of the MOS short form-12 (SF12) health status questionnaire with the SF36 in patients with rheumatoid arthritis.

OBJECTIVE: To compare the performance of the MOS SF12 health survey (SF12) with the SF36 in a sample of 233 patients with rheumatoid arthritis (RA) stratified by functional class. METHODS: The SF12 and SF36 physical and mental component summary scales (PCS and MCS) were compared for test retest reliability [intra-class correlation coefficient (RC) and repeatability], construct validity and responsiveness [standardized response mean (SRM)] to self-reported change in health. RESULTS: Overall, despite its brevity, the SF12 is comparable to the SF36 with only some loss of performance. The SF12-PCS is slightly less reliable (RC = 0.75) and responsive to improvements in health (SRM = 0.52) than the SF36-PCS (RC = 0.81; SRM = 0.61). The SF12-PCS correlates strongly with the SF36-PCS (R = 0.94), SF36 physical function subscale (R = 0.77) and modified Stanford Health Assessment Questionnaire (MHAQ) (R = 0.71), but only weakly with the SF36 mental health subscale (R = 0.22). SF12-PCS discriminated well between Steinbrocker functional classes; patients in functional classes 1-4, respectively, have SF12-PCS scores 1sigma, 2sigma, 2.4sigma and 2.7sigma below the population norm (ANOVA, F = 35.8, P < 0.000). The SF12-MCS is relatively unresponsive to reported improvement in RA (SRM = 0.31), but is reliable (RC = 0.71) and correlates well with the SF36-MCS (R = 0.71). SF12-MCS correlates more closely than the SF36-MCS with the SF36 mental health subscale (R = 0.86) and Hospital Anxiety and Depression (HAD) scale (R = 0.76). In ANOVA models, only the HAD (R2 = 57%) score contributes significantly to variance in SF12-MCS (F = 254.8; P < 0.000), but both the HAD (R2 = 24%) and MHAQ (R2 = 10%) scores contribute to variance in the SF36-MCS (F = 50.9; P < 0.000). Thus, the SF12-MCS has better construct validity for mental health than SF36-MCS in RA subjects. Missing responses to items were high amongst patients in functional class 4 (34%). CONCLUSION: The SF12 is a reliable, valid and responsive measure of health status in the majority of RA patients, and meets standards required for comparing groups of patients. Its application in the most severely disabled subjects is uncertain.

Adult↗
PubMed1999

Picrotoxin in the medial prefrontal cortex impairs sensorimotor gating in rats: reversal by haloperidol.

RATIONALE: Neuropathological data indicate a GABAergic dysfunction in the prefrontal cortex and hippocampus of schizophrenics. On this basis, the construct validity of an animal model of schizophrenia was tested. OBJECTIVE: This study assessed prepulse inhibition (PPI) of startle in rats after injections of the GABA antagonist picrotoxin into the prefrontal cortex and the ventral hippocampus. It was also tested if reductions in PPI are reversed by the dopamine antagonist haloperidol. PPI is a measure of sensorimotor gating and is impaired in schizophrenia patients. The hypothesis underlying this study was that blockade of prefrontocortical and hippocampal GABA receptors disrupts PPI in a dopamine-dependent way. This hypothesis was based on neuropathological data from schizophrenics indicating a loss of GABAergic neurons in the prefrontal cortex and hippocampus and on the observation that PPI is reduced in schizophrenics. METHODS: Picrotoxin (0, 5, 10 ng/0.5 microl) was infused through chronically indwelling cannulae into the medial prefrontal cortex (mPFC), into the lateral prefrontal cortex and into the ventral hippocampus. The effect on PPI was measured directly after picrotoxin infusion. The neuroleptic compound haloperidol (0.1 mg/kg) was administered intraperitoneally 30 min before testing. RESULTS: Picrotoxin in the mPFC dose-dependently reduced PPI and this effect was antagonized by systemic pretreatment with the dopamine antagonist haloperidol. No significant effects on PPI were observed after picrotoxin infusions into the lateral prefrontal cortex or into the ventral hippocampus. CONCLUSIONS: These findings indicate that acute blockade of GABA receptors in the mPFC impairs sensorimotor gating in a dopamine-dependent manner. Since PPI in rats has been shown to possess face, predictive, and construct validity as an animal model for some psychotic symptoms, we discuss the potential relevance of our findings for the pathophysiology of schizophrenia.

Animals↗
PubMed2002

The physical activity scale for individuals with physical disabilities: development and evaluation.

OBJECTIVE: To evaluate the construct validity of a new 13-item physical activity survey designed to assess physical activity in individuals with physical disabilities. DESIGN: Mail survey requesting information on physical activity, basic demographic characteristics, self-rated health, and self-rated physical activity. SETTING: In February 2000, surveys were sent to 1176 individuals who had used rehabilitative services at a major midwestern university between 1950 and 1999. PARTICIPANTS: Two hundred twenty-seven men and 145 women with disabilities responded to the mail survey (80%, spinal cord or other locomotor injuries; 13%, visual and auditory injuries; 7%, other; 92%, white; mean age +/- standard deviation, 49.8 +/- 12.9y; mean length of disability, 36.9 +/- 14.9y). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Physical activity was assessed with the Physical Activity Scale for Individuals with Physical Disabilities (PASIPD). The PASIPD requests the number of days a week and hours daily (categories) of participation in recreational, household, and occupational activities over the past 7 days. Total scores were calculated as the average hours daily times a metabolic equivalent value and summed over items. RESULTS: Pearson correlations between each survey item and the total PASIPD score were all statistically significant (P < .05) and >or= .20 (range, .20- .67). Factor analysis with principal component extraction and varimax orthogonal rotations revealed 5 latent factors (eigenvalues >or= 1, factor loadings >or= .40): home repair and lawn and garden, housework, vigorous sport and recreation, light sport and recreation, and occupation and transportation. These 5 factors accounted for 63% of the total variance. Cronbach alpha coefficients ranged from.37 to.65, indicating low-to-moderate internal consistency within factors. Those who reported being "active/highly active" had higher total and subcategory scores compared with those "not active at all." Those in "excellent" health had higher total, vigorous sport and recreation, and occupation and transportation subcategory scores compared with those who rated their health "fair/poor" (all P < .05). CONCLUSION: These results provide preliminary support for the construct validity of the PASIPD. Additional validation studies using an external criterion and in more generalizable samples are warranted.

Activities of Daily Living↗
PubMed1998

Assessing the value of a new pharmaceutical. A feasibility study of contingent valuation in managed care.

OBJECTIVES: The authors assessed the feasibility and construct validity of the contingent valuation method for measuring the monetary value to healthy enrollees in a health maintenance organization of a new drug, filgrastim, as prophylaxis against febrile neutropenia after chemotherapy treatment for cancer. METHODS: A random sample of 220 enrollees from a closed-panel staff-model health maintenance organization who did not have cancer were interviewed. Chemotherapy, febrile neutropenia and filgrastim were described by video and decision board. Questions were asked in two different scenarios: (1) User-based: Assuming they were at the point of consumption and about to receive chemotherapy, what is the maximum they would be willing to pay to receive filgrastim? and (2) Insurance-based: Given they were at risk of cancer in the future, what is the maximum they would be willing to pay in additional monthly insurance premiums to add filgrastim to the plan? In a second insurance scenario where respondents were told that filgrastim was covered, what is the minimum reduction in premium that persons were willing to accept to relinquish coverage of the drug? A 2 x 2 factorial design was used to contrast two bidding algorithms to test for starting point bias and two 5-yearly prior risks of cancer, 1/200 versus 1/100. Main effects were tested by ANCOVA controlling for age, sex, health, and income. RESULTS: Demographics of experimental cells were similar. No evidence was found of significant starting point bias. For user-based questions, as expected, willingness-to-pay increases with febrile neutropenia risk reduction, but at a declining marginal rate. Despite careful presentation of information to respondents, willingness-to-pay for insurance was higher in the lower prior risk group. Consistent with previous contingent valuation studies, the authors of the present study found evidence that willingness-to-accept exceeds willingness-to-pay for coverage of the same benefit. CONCLUSIONS: An insurance-based contingent valuation study is feasible in a health maintenance organization. Construct validation evidence was encouraging, with the exception of the test for prior risk of cancer; however, this was a between-person contrast and may have been confounded by other factors.

Adult↗
PubMed2004

Effects of olanzapine alone and olanzapine/fluoxetine combination on health-related quality of life in patients with bipolar depression: secondary analyses of a double-blind, placebo-controlled, randomized clinical trial.

BACKGROUND: Improving patients' health-related quality of life (HRQOL) could be a treatment goal for bipolar depression. OBJECTIVES: The objectives of these secondary analyses of a previous report were to determine the benefits of olanzapine alone and olanzapine-fluoxetine combination (OFC) for improving HRQOL in patients with bipolar depression using both a generic and a depression-specific HRQOL instrument, and to examine the association between the 2 HRQOL instruments and the construct validity of the depression-specific HRQOL instrument. METHODS: This was a double-blind, placebo-controlled, 83-site, international, randomized trial. Adults with bipolar I disorder, most recent episode depressed (according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition), were randomly assigned to receive olanzapine (6-20 mg/d), OFC (6/25, 12/25, or 12/50 mg/d), or placebo for 8 weeks. HRQOL improvement was calculated as last-observation-carried-forward changes in dimension and component summary scores on Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) and total score on the Quality of Life in Depression Scale (QLDS). RESULTS: Patients were assigned to receive olanzapine (n = 370), [corrected] OFC (n = 86), or placebo (n = 377) [corrected] for 8 weeks. Of 833 enrolled patients, 454 discontinued (olanzapine, 191/370 [51.6%] [corrected]OFC, 31/86 [36.0%]; and placebo, 232/377 [61.6%]) [corrected] Compared with placebo, olanzapine-treated patients exhibited greater improvements on SF-36 mental component summary (MCS) score ( P=0.002) and 3 of 8 SF-36 dimension scores (mental health [P=0.015], role-emotional [P=0.046], and social functioning [P=0.006). OFC-treated patients exhibited greater improvements on MCS score ( P<0.001) vs both placebo and olanzapine), 5 SF-36 dimension scores (general health perception (P<0.001) vs placebo; (P<0.001) vs olanzapinel, mental health [ P=0.001] vs both placebo and olanzapine], role-emotional [ P<0.001] vs placebo; [P=0.007] vs olanzapine], social functioning [ P=0.001] vs placebo; [P=0.032] vs olanzapine], and vitality [P=0.002] vs placebo; [P=0.011] vs olanzapine]), and QLDS total score ( P<0.001] vs both placebo and olanzapine). Changes in SF-36 scores of mental health, social functioning, role-emotional, and vitality were highly correlated to changes in the QLDS total score (all p < -0.5). CONCLUSIONS: Based on these analyses, patients with bipolar depression receiving olanzapine or OFC for 8 weeks had greater improvement in HRQOL than those receiving placebo. OFC treatment was associated with greater improvement in HRQOL than olanzapine alone. The correlation results support the construct validity of the QLDS.

Adult↗
PubMed1985

Development of a random response scale for the child abuse potential inventory.

The present research employed a total of 479 subjects in three studies to develop and initially validate a random response scale for the Child Abuse Potential Inventory. Preliminary norm and reliability estimates are reported (Study One). Cross-validation (Study Two) and construct validity (Study Three) data are provided that indicate that the random response scale is stable across groups and can discriminate normal responders from those instructed to respond in a random, haphazard manner.

Child Abuse↗
PubMed2004

Construction and validation of a microprocessor controlled extracorporal circuit in rats for the optimization of isolated limb perfusion.

Although a few experimental approaches to isolated limb perfusion (ILP) are described in the literature, none of these animal models mimics the clinical perfusion techniques adequately to improve the technique of ILP on the basis of valid preclinical data. Therefore, we developed an ILP setup in rats allowing online monitoring of essential perfusion parameters such as temperature (in perfusate, various tissues, and rectum), pH (perfusate), perfusion pressure, and O(2) concentration (in perfusate, tissue), by a tailor-made data acquisition system. This setup permits close supervision of vital parameters during ILP. Various interdependencies, concerning the flow rate and the pressure of perfusate as well as tissue oxygenation were registered. For the measurement of pO(2) values in the perfusate and in different regions of the perfused hind limb, a novel type of microoptode based on quenching of a fluorescent dye was devised. Stable normothermic (37 degrees C) perfusion conditions were maintained at a constant perfusion pressure in the range of 40-60 mm Hg by administration of the spasmo lytic moxaverine (0.5 mg/mL of perfusate as initial dose) at a perfusate flow rate of 0.5 mL/min for 60 min. At the end of an ILP, there were no signs of tissue damage, neither concerning laboratory data (K(+), myoglobin, creatine kinase, lactic dehydrogenase) nor histopathological criteria. The reported ILP model is not only well suited to investigate the effects of hyperthermia but also to assess the efficacy of new antineoplastic approaches, when nude rats, bearing human tumours in the hind limbs, are used.

Animals↗
PubMed1996

[Construction and validation of an indicator for alcohol problems in the Swiss Health Survey].

A proposed scale for alcohol problems which consisted of five items, was psychometrically examined and validated. Latent class analysis was used in addition to classic psychometric measures. The use of this scale in health surveys of the general population seems to be justified, as it offers a reliable and very economic method to measure alcohol induced problems. It is therefore proposed that this scale should continue to be used in future rounds of the Swiss Health Survey. The context of the questioning has to be taken into account when interpreting the summary score, as items showed different patterns of response in personal vs interview questionnaires.

Alcoholism↗
PubMed2006

Validation of the German prostate-specific module.

Theoretically, all patients newly diagnosed with prostate cancer are faced with a choice of treatment options: radical prostatectomy or radio therapy. Although these different treatments may have no differences in terms of survival, they may have very different consequences on the subsequent quality of life (QoL). Prerequisite to analyze QoL is a reliable and valid instrument to assess these differences not only in terms of general QoL (EORTC QLQ-C30) but prostate specific symptoms with a prostate specific module as well. Therefore, the aim of this study was a psychometric evaluation (validation) of the prostate-specific module (PSM). Five historical cohort studies were put together for an empirical meta-analysis. The main objective was to analyze the module's psychometric properties. The total sample consisted of 1,185 patients, of whom 950 completed the QoL questionnaires (EORTC QLQ-C30 and a prostate specific module developed by Kuechler et al.). First step of analysis was a principal component analysis that revealed the following scales: urinary problems, incontinence, erectile dysfunction, sexual problems, problems with partner, pain, heat, nutrition, and psychic strain. The module showed good reliability and concurrent validity and very good construct validity, since the module is able to discriminate between different treatment regimes, tumor stages and age. The German PSM is a reliable, valid and applicable tool for QoL in patients with prostate cancer.

Adaptation, Psychological↗
PubMed1983

Facet theory applied to the construction and validation of the Aachen Aphasia Test.

The linguistic performance of 120 aphasic patients of the four standard syndromes assessed by the Aachen Aphasia Test (AAT) is analyzed by a nonmetric (ordinal) multidimensional scaling procedure (Smallest Space Analysis, SSA1). The linguistic structure of the test items is characterized within the framework of L. Guttman's facet theory. Three systematic components (facets) are discerned: linguistic modality, unit, and regularity. Properties of the facets as well as their relations are assessed and tested empirically by analyzing the interrelations among different items or sets of items. The spatial configurations obtained by the scaling procedure fit only partially the expectations derived from the facet-theory model. The modality facet was found to have a strong overriding influence on the aphasic test performance. The facets unit and regularity were only found for the most rigorously designed subtests. Written Language and Comprehension. The results suggest the introduction of a new combined facet linguistic complexity which reflects the dependency of the facets regularity and unit.

Adult↗
PubMed2006

Animal models of behavioral dysfunctions: basic concepts and classifications, and an evaluation strategy.

In behavioral neurosciences, such as neurobiology and biopsychology, animal models make it possible to investigate brain-behavior relations, with the aim of gaining insight into normal and abnormal human behavior and its underlying neuronal and neuroendocrinological processes. Different types of animal models of behavioral dysfunctions are reviewed in this article. In order to determine the precise criteria that an animal model should fulfill, experts from different fields must define the desired characteristics of that model at the neuropathologic and behavioral level. The list of characteristics depends on the purpose of the model. The phenotype-abnormal behavior or behavioral dysfunctions-has to be translated into testable measures in animal experiments. It is essential to standardize rearing, housing, and testing conditions, and to evaluate the reliability, validity (primarily predictive and construct validity), and biological or clinical relevance of putative animal models of human behavioral dysfunctions. This evaluation, guided by a systematic strategy, is central to the development of a model. The necessity of animal models and the responsible use of animals in research are discussed briefly.

Animals↗
PubMed2003

Construction and validation of a Sinorhizobium meliloti whole genome DNA microarray: genome-wide profiling of osmoadaptive gene expression.

Based on the complete Sinorhizobium meliloti genome sequence we established DNA microarrays as a comprehensive tool for systematic genome-wide gene expression analysis in S. meliloti 1021. For these PCR fragment-based microarrays, called Sm6kPCR, a collection of probes for the 6207 predicted protein-coding genes consisting of 6046 gene-specific PCR fragments and 161 70 mer oligonucleotides was arrayed in high density on glass slides. To obtain these PCR fragments primer pairs were designed to amplify internal gene-specific DNA fragments of 80-350 bp. Additionally, these primers were characterized by a 5' extension that allowed for reamplification using standard primers after the first amplification employing the specific primers. In order to ascertain the quality of the Sm6kPCR microarrays and to validate gene expression studies in S. meliloti parallel hybridizations based on RNA samples obtained from cells cultured under identical conditions were performed. In addition, gene expression in S. meliloti in response to an osmotic upshift imposed by the addition of 0.38 M NaCl was monitored. 137 genes were identified showing significant changes in gene expression resulting from the osmotic upshift. From these genes 52 were induced and 85 genes were repressed. Among the genes displaying different RNA levels some functional groups could be identified that are particularly remarkable. Repression was observed for 8 genes related to motility and chemotaxis, 7 genes encoding amino acid biosynthesis enzymes and 15 genes involved in iron uptake whereas 14 genes involved in transport of small molecules and 4 genes related to polysaccharide biosynthesis were induced.

Chromosome Mapping↗
PubMed2005

A motor function measure for neuromuscular diseases. Construction and validation study.

A new scale for motor function measurement has been developed for neuromuscular diseases. The validation study included 303 patients, aged 6-62 years. Seventy-two patients had Duchenne muscular dystrophy, 32 Becker muscular dystrophy, 30 limb-girdle muscular dystrophy, 39 facio-scapulo-humeral dystrophy, 29 myotonic dystrophy, 21 congenital myopathy, 10 congenital muscular dystrophy, 35 spinal muscular atrophy and 35 hereditary neuropathy. The scale comprised 32 items, in three dimensions: standing position and transfers, axial and proximal motor function, distal motor function. Agreement coefficients for inter-rater reliability were excellent (kappa=0.81-0.94) for nine items, good (kappa=0.61-0.80) for 20 items and moderate (kappa=0.51-0.60) for three items. High correlations were found between the total score and other scores: Vignos (r=0.91) and Brooke (r=0.85) grades, Functional Independence Measure (r=0.91), the global severity of disability evaluated with visual analog scales by physicians (r=0.88) and physiotherapists (r=0.91). This scale is reliable, does not require any special equipment and is well-accepted by patients. Its sensitivity to change is being assessed to permit its use in clinical trials of neuromuscular diseases.

Adolescent↗
PubMed2006

Respirometric 13C flux analysis, Part I: design, construction and validation of a novel multiple reactor system using on-line membrane inlet mass spectrometry.

A novel method for (13)C flux analysis based on on-line CO(2) labeling measurements is presented. This so-called respirometric (13)C flux analysis requires multiple parallel (13)C labeling experiments using differently labeled tracer substrates. In Part I of the work, a membrane-inlet mass spectrometry-based measurement system with 6 parallel reactors with each 12 ml liquid volume and associated experimental and computational methods for the respirometric (13)C data acquisition and evaluation are described. Signal dynamics after switching between membrane probes follow exactly first-order allowing extrapolation to steady state. Each measurement cycle involving 3 reactors takes about 2 min. After development of a dynamic calibration method, the suitability and reliability of the analysis was examined with a lysine-producing mutant of Corynebacterium glutamicum using [1-(13)C(1)], [6-(13)C(1)], [1,6-(13)C(2)] glucose. Specific rates of oxygen uptake and CO(2) production were estimated with an error less than +/-0.3 mmol g(-1) h(-1) and had +/-3% to +/-10% deviations between parallel reactors which is primarily caused by inaccuracies in initial biomass concentration. The respiratory quotient could be determined with an uncertainty less than +/-0.02 and varied only +/-3% between reactors. Fractional labeling of CO(2) was estimated with much higher precision of about +/-0.001 to +/-0.005. The detailed statistical analysis suggested that these data should be of sufficient quality to allow physiological interpretation and metabolic flux estimation. The obtained data were applied for the respirometric (13)C metabolic flux analysis in Part II.

Bioreactors↗