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PubMed2006

Molecular dynamics comparative study of Lennard-Jones -6 and exponential -6 potentials: application to real simple fluids (viscosity and pressure).

In this work, using molecular dynamics simulation, the viscosity (dynamic property) and the pressure (static property) of spherical fluid particles interacting through Lennard-Jones -6 and exponential -6 potentials are computed. Simulations are performed for going from 10 to 20 for the Lennard-Jones potential and from 12 to 22 for the exponential one. Six different thermodynamic states are tested that cover a large range of conditions, from sub- to supercritical temperature and from low to high density. To compare in a consistent manner the results for the various potentials tested, the simulations are carried out for the same set of reduced thermodynamic conditions (using the critical point). It is found that a perfect corresponding-states formulation is not possible between these potentials. Then, these potentials are applied on real simple fluids (argon, oxygen, nitrogen, methane, ethane, and one mixture, air) and the calculated viscosity and pressure values are compared with reference values. It appears that, using the appropriate , both potential families lead to a good accuracy in pressure and viscosity using the same set of molecular parameters for both properties, the average absolute deviations being always lower than 5% for the studied states. In addition, it is shown that the exponential potential results do not outperform the Lennard-Jones ones. Furthermore, for all compounds except for methane, the best results are obtained for the Lennard-Jones 12-6 and the exponential 14-6 potentials. This result partly explains why, despite no theoretical background, the Lennard-Jones 12-6 potential is so widely used. Finally, it is shown that a van der Waals one-fluid model performs extremely well for the studied mixture (air).

Journal Article↗

PubMedDate not supplied

Prognostic factors in patients with advanced biliary tract cancer receiving chemotherapy.

BACKGROUND/AIMS: Prognostic factors in patients with advanced biliary tract cancer receiving chemotherapy have not been fully examined. This study investigated prognostic factors in patients with advanced biliary tract cancer receiving chemotherapy. METHODOLOGY: Sixty-five consecutive chemo-naive patients with advanced biliary tract cancer, who received chemotherapy, were analyzed retrospectively to investigate prognostic factors. RESULTS: Median survival time and overall survival rates at 1 and 2 years were 180 days, 21%, and 5%, respectively. By multivariate analysis using the Cox proportional hazards model, performance status of 0, 1, serum C-reactive protein level of < or = 1.0mg/dL, serum albumin level of > or = 3.5g/dL, serum lactate dehydrogenase level of < or = 500 U/L, and being female were independent favorable prognostic factors. A prognostic index based on the coefficients of these prognostic factors was used to classify patients into three groups with good, intermediate, and poor prognoses. The median survival times for these three groups were 246, 152, and 33 days, respectively. CONCLUSIONS: The results may be helpful for predicting life expectancy, determining treatment strategies, and designing future clinical trials in patients with advanced biliary tract cancer.

Adult↗

PubMed1994

Evidence for nonretinal feedback in combined version-vergence eye movements.

Recently, a quantitative model for the general of rapid eye movements in direction and depth was proposed. In this scheme, the saccadic and the vergence system share a common initiation system and are controlled by local feedback loops based on efference copy signals. We have used a remembered-target double-step paradigm to test the idea that both subsystems are guided by extraretinal signals. The subject was instructed to move the binocular point of fixation to the remembered positions indicated by a double-step movement of the target, in direction and depth. Since both binocular refixations were made in complete darkness, correct execution of this task requires information about both the stored visual coordinates of the final target and the coordinates of the first movement. Binocular eye movements from five subjects were compared with predictions from two feed-forward models and a feedback model. Analysis of the pooled direction data showed that the feedback model performed best and fitted well. Qualitatively the same result was obtained in the vergence component, but in this case the goodness of fit was considerably less. These results, confirmed in each individual subject, show that the saccadic and vergence subsystem can use nonretinal information about a prior movement in direction and depth. Further analysis showed that the gain of the direction response of the second movement was, on average, roughly correct. By contrast, the vergence component of these responses was only about 60% of the required amplitude. Since the fit procedure gave the same weighting factors to the second target and to the first movement, we propose that the low vergence gain reflects mechanisms operating after the calculation of the motor error signal, possibly at the execution stage. Finally, we discuss the possibility of a central control stage keeping track of the ongoing movement sequence, based on a comparison of desired and current eye position signals.

Adult↗

PubMed2007

Predicting physical activity and general health perception among patients with rheumatoid arthritis.

OBJECTIVE: To describe changes over one year in physical activity, body functions, and disease activity in patients with rheumatoid arthritis (RA) and to identify predictors for physical activity and general health perception. METHODS: One hundred two patients with RA were recruited for the study (median age 57 yrs, range 19-84; median disease duration 15 mo, range 4-78; 76% women). Self-reported data on physical activity and health locus of control, tests of lower extremity function, grip force, joint range of motion, balance, and measures of disease activity, including pain, general health perception, Health Assessment Questionnaire (HAQ), and Disease Activity Score (DAS28), were collected on 2 occasions, one year apart. Each variable was dichotomized to fit logistic regression models, performed to identify which variables predicted physical activity and general health perception over one year. RESULTS: Physical activity was stable, while lower extremity function, grip force, and range of motion improved and DAS28 decreased significantly over one year. A high physical activity level at baseline was the only predictor of high physical activity (odds ratio 3.85, 95% confidence interval 1.67-9.09) one year later. Low pain (OR 8.47, 95% CI 2.97-24.39), high physical activity (OR 3.72, 95% CI 1.39-10.10), and good lower extremity function (OR 2.94, 95% CI 1.04-8.33) were identified as predictors of good general health perception. CONCLUSION: While pain is a well known predictor of general health perception, to our knowledge, this is the first study to identify predictive factors related to physical activity and lower extremity function as important for perceived health among patients with RA.

Adult↗

PubMed1992

Exploring time trends in cancer incidence.

We examined incidence time-trends for lung, stomach, intestinal, prostate, and breast cancer among Whites diagnosed in the United States between 1973 and 1987. For each sex and five-year age group, we modeled cancer incidence as a log-linear function of diagnosis-year to permit extrapolation over time and simple summarization of trends. Comparisons with nonparametric estimates show that, except for breast cancer, the model performs well. Plots of the annual percent change in incidence cf age illustrate the way in which time trends depend on age. Between 1973 and 1987, stomach cancer incidence decreased by about two percent per year. The annual change in lung cancer incidence progressed from a two to three percent decrease in persons under age 40 to an increase of two percent in men and eight percent in women by age 80. Intestinal cancer incidence decreased annually by as much as three percent in persons under age 50, remained constant in women aged 50 to 74, and otherwise increased about one percent per year. The annual increase in prostate cancer incidence declined from about six percent in men under age 40 to about two percent in men over age 80. After a surge in female breast-cancer diagnoses in 1974, the annual increase in incidence between 1980 and 1987 stabilized at four to six percent.

Adult↗

PubMedDate not supplied

[Probabilistic cost-effectiveness analysis of the treatment of sleep apnea].

OBJECTIVE: To describe the application of a probabilistic cost-effectiveness analysis to nasal continuous positive airway passage (nCPAP) treatment of obstructive sleep apnea syndrome (OSAS). MATERIAL AND METHODS: The probabilistic model was constructed from a discrete Markov model. This probabilistic approach is characterized by the introduction of variables as probability distributions. The model performed 2,000 Monte Carlo simulations, and incremental costs and effectiveness were calculated in each. The results were analyzed through the cost-effectiveness plane, the acceptability curve, the net benefit rule, and the expected value of perfect information (EVPI). RESULTS: The mean cost-effectiveness ratio for nCPAP treatment was 5,480 Euro/QALY (quality-adjusted life year). Using an acceptability threshold of 30,000 Euro/QALY, the probabilistic analysis showed that nCPAP was the optimal treatment in 98.5% of the simulations. The EVPI showed that the parameter causing greatest uncertainty in the final results was the quality of life gain through nCPAP treatment. CONCLUSIONS: The results of our probabilistic analysis are endorsed by previous deterministic studies confirming that nCPAP treatment of OSAS is the most cost-effective strategy. An additional advantage of probabilistic analysis is that it allows uncertainty to be quantified; in the present case the probability of making the wrong decision was below 5%. Furthermore, this study reveals that to reduce uncertainty, research should center on improving information on quality of life.

Continuous Positive Airway Pressure↗

PubMed2005

Incremental online learning in high dimensions.

Locally weighted projection regression (LWPR) is a new algorithm for incremental nonlinear function approximation in high-dimensional spaces with redundant and irrelevant input dimensions. At its core, it employs nonparametric regression with locally linear models. In order to stay computationally efficient and numerically robust, each local model performs the regression analysis with a small number of univariate regressions in selected directions in input space in the spirit of partial least squares regression. We discuss when and how local learning techniques can successfully work in high-dimensional spaces and review the various techniques for local dimensionality reduction before finally deriving the LWPR algorithm. The properties of LWPR are that it (1) learns rapidly with second-order learning methods based on incremental training, (2) uses statistically sound stochastic leave-one-out cross validation for learning without the need to memorize training data, (3) adjusts its weighting kernels based on only local information in order to minimize the danger of negative interference of incremental learning, (4) has a computational complexity that is linear in the number of inputs, and (5) can deal with a large number of-possibly redundant-inputs, as shown in various empirical evaluations with up to 90 dimensional data sets. For a probabilistic interpretation, predictive variance and confidence intervals are derived. To our knowledge, LWPR is the first truly incremental spatially localized learning method that can successfully and efficiently operate in very high-dimensional spaces.

Algorithms↗

PubMed2025

Predicting host tropism in influenza a viruses: insights from multi-segment nucleotide signatures.

BACKGROUND: Influenza A virus (IAV) poses a significant public health threat due to its cross-species transmission and complex host adaptation mechanisms. This study integrated whole-genome data from avian, human, swine, and bovine IAV strains, using machine learning to predict viral host tropism based on nucleotide site features and to identify key sites driving host adaptation along with their synergistic effects. METHODS: A total of 64,000 IAV sequences from avian, human, swine, and bovine hosts were analyzed to build host-prediction models. A four-class classification framework (avian, human, swine, bovine) was constructed using nucleotide site features from all eight genomic segments (PB2, PB1, PA, HA, NP, NA, MP, NS). Eight machine learning algorithms (logistic regression, decision tree, random forest, SVM, KNN, gradient boosting, XGBoost, LightGBM) were benchmarked via 10-fold stratified cross-validation. Model performance was evaluated using accuracy, precision, recall, F1-score, AUPRC, and AUC. SHAP (SHapley Additive exPlanations) analysis prioritized critical nucleotide sites, while bivariate association tests identified synergistic/antagonistic interactions between sites. Nucleotide composition profiles were compared across host groups using hierarchical clustering and heatmap visualization. RESULTS: The XGBoost algorithm demonstrated the best and most stable performance, achieving an AUC value of over 0.95 in distinguishing human-derived sequences from non-human ones. SHAP analysis identified the top 20 critical nucleotide sites for each gene segment, such as sites 46 and 698 in the NS segment. Nucleotide composition analysis revealed high similarity between human and swine sequences in the HA and PB2 segments, and between avian and bovine sequences. The HA segment was particularly challenging in differentiating human from swine strains. Bivariate site association analysis uncovered significant synergistic or antagonistic effects between key sites within gene segments, forming complex networks. For instance, in the NS segment, a positive prediction contribution was observed when sites 371, 698, and 419 were all G. CONCLUSIONS: This study advances our mechanistic understanding of IAV host adaptation, identifies molecular determinants for zoonotic risk stratification, and establishes a scalable machine learning framework for predicting viral host tropism through nucleotide signature analysis, thereby enhancing surveillance strategies and informing preventive measures against emerging viral threats.

Influenza A virus↗

PubMed1998

The tissue effects of ultrasound-assisted lipoplasty.

The objective of our study was to investigate the effects of ultrasonic energy on tissues, using a porcine model, performed under various instrumental and procedural parameters. Domestic pigs were anesthetized and prepared for surgery. An incision was made on the side of the hip randomly assigned to the right or left side. Tumescence solution was infiltrated via a blunt tip, small diameter cannula, followed by performance of standard liposuction. On the contralateral side, a similar incision was made. For ultrasonic liposuction experiments without the sheath, a percutaneous introducer was inserted into the incision, which was protected at the entry site from contact with the cannula. Tumescence solution was infiltrated via a blunt tip, small diameter cannula, and then the site was treated with ultrasonic energy at maximum output from the machine with liposuction concurrent through the hollow cannula. The experiments with the sheath did not require a pretreatment with tumescence solution but consisted of tumescence solution pumped through the sheath at a low infusion rate, with concurrent treatment utilizing ultrasonically assisted liposuction through the central lumen of the cannula. In all cases, the lipoaspirate was preserved for biochemical analysis. After treatment, the pigs were euthanized, and samples for histopathology were taken. The pigs were then perfused with a radio-opaque solution through the left ventricle following preperfusion with saline. The groups were ultrasound-assisted liposuction with sheath (n = 3), ultrasound-assisted without sheath (n = 4), and tumescence alone (n = 1), with standard liposuction performed on the contralateral side for all ultrasound-assisted liposuction animals. The lipoaspirates from the ultrasonically assisted liposuction with the sheath showed significantly less blood loss (measured as hemoglobin in the aspirate) than standard liposuction (p = 0.012) at comparable levels of fat (measured as triglycerides in the aspirate). The lipoaspirates from ultrasound-assisted liposuction without the sheath showed blood loss comparable to that experienced with standard liposuction. The ratio of hemoglobin to triglyceride was lowest in the ultrasound-assisted group with (p = 0.01) and without (p = 0.06) the sheath when compared to traditional liposuction. In both of these treated groups, the radiograms of the perfused areas showed significantly less vascular disruption when compared with suction-assisted liposuction. Histopathologic examination of specimens taken from various treated areas showed substantial tissue damage comparable in ultrasound- and suction-assisted liposuction treated groups. This preliminary experimental study showed that ultrasound-assisted lipoplasty is comparable to traditional suction-assisted lipoplasty. Treatment with ultrasound provided more significant hemoglobin/triglyceride ratios, indicative of more lipid aspirated per hemoglobin lost, and better preservation of vascular tissues as demonstrated by our perfusion studies. Treatment with the sheath showed a significantly lower hemoglobin release with a diminished volume infused into the subcutaneous space during the procedure.

Acetylcholinesterase↗

PubMed2000

The potential clinical and economic benefits of silver alloy urinary catheters in preventing urinary tract infection.

BACKGROUND: Catheter-associated urinary tract infection (UTI) is associated with increased morbidity, mortality, and costs. A recent meta-analysis concluded that silver alloy catheters reduce the incidence of UTI by 3-fold; however, clinicians must decide whether the efficacy of such catheters is worth the extra per unit cost of $5.30. OBJECTIVE: To assess the clinical and economic impact of using silver alloy urinary catheters in hospitalized patients. METHODS: The decision model, performed from the health care payer's perspective, evaluated a simulated cohort of 1000 hospitalized patients on general medical, surgical, urologic, and intensive care services requiring short-term urethral catheterization (2-10 days). We compared 2 catheterization strategies: silver alloy catheters and standard (noncoated) urinary catheters. Outcomes included the incidence of symptomatic UTI and bacteremia and direct medical costs. RESULTS: In the base-case analysis, use of silver-coated catheters led to a 47% relative decrease in the incidence of symptomatic UTI from 30 to 16 cases per 1000 patients (number needed to treat = 74) and a 44% relative decrease in the incidence of bacteremia from 4.5 to 2.5 cases per 1000 patients (number needed to treat = 500) compared with standard catheters. Use of silver alloy catheters resulted in estimated cost savings of $4.09 per patient compared with standard catheter use ($20.87 vs $16.78). In a multivariate sensitivity analysis using Monte Carlo simulation, silver-coated catheters provided clinical benefits over standard catheters in all cases and cost savings in 84% of cases. CONCLUSIONS: Using silver alloy catheters in hospitalized patients requiring short-term urinary catheterization reduces the incidence of symptomatic UTI and bacteremia, and is likely to produce cost savings compared with standard catheters.

Alloys↗

PubMedDate not supplied

A new Simplified Acute Physiology Score (SAPS II) based on a European/North American multicenter study.

OBJECTIVE: To develop and validate a new Simplified Acute Physiology Score, the SAPS II, from a large sample of surgical and medical patients, and to provide a method to convert the score to a probability of hospital mortality. DESIGN AND SETTING: The SAPS II and the probability of hospital mortality were developed and validated using data from consecutive admissions to 137 adult medical and/or surgical intensive care units in 12 countries. PATIENTS: The 13,152 patients were randomly divided into developmental (65%) and validation (35%) samples. Patients younger than 18 years, burn patients, coronary care patients, and cardiac surgery patients were excluded. OUTCOME MEASURE: Vital status at hospital discharge. RESULTS: The SAPS II includes only 17 variables: 12 physiology variables, age, type of admission (scheduled surgical, unscheduled surgical, or medical), and three underlying disease variables (acquired immunodeficiency syndrome, metastatic cancer, and hematologic malignancy). Goodness-of-fit tests indicated that the model performed well in the developmental sample and validated well in an independent sample of patients (P = .883 and P = .104 in the developmental and validation samples, respectively). The area under the receiver operating characteristic curve was 0.88 in the developmental sample and 0.86 in the validation sample. CONCLUSION: The SAPS II, based on a large international sample of patients, provides an estimate of the risk of death without having to specify a primary diagnosis. This is a starting point for future evaluation of the efficiency of intensive care units.

Adult↗

PubMed1998

Effect of different starches on Escherichia coli (S1) beta-glucuronidase expression.

Studies with pure cultures growing in laboratory media indicated that beta-glucuronidase expression of Escherichia coli S1 was considerably affected by starch added to the medium as the only carbon source. This result, which may be an aspecific modulation of enzyme expression, was independent of the starch molecular structure and effects were analogous for maize, rice, wheat or potato starches. It was observed that enzyme expression was little affected by the growth rate. The beta-glucuronidase activities of starch-grown bacteria found in the present study agree with those observed in animal and human models performed for in vivo evaluation of effects of dietary starch effects on gut microbial ecosystems.

Culture Media↗

PubMed2004

Measuring systemic lupus erythematosus activity during pregnancy: validation of the lupus activity index in pregnancy scale.

OBJECTIVE: To validate the Lupus Activity Index in Pregnancy (LAI-P) scale as a diagnostic tool for lupus flares during pregnancy and the puerperium. METHODS: The LAI-P is a modified activity scale specific for pregnancy. Thirty-eight pregnant women with systemic lupus erythematosus (SLE) were prospectively followed in 3 clinics specific for lupus in pregnancy. On each visit, LAI-P was calculated. A modified physician global assessment (m-PGA) scale was used as gold standard (0 = no activity, 1 = mild-moderate activity, 2 = severe activity). A change > or = 0.25 in LAI-P was predefined as a flare according to previous studies in nonpregnant patients. For the purposes of the study, each visit was considered as an independent case. RESULTS: During the study period, 158 visits took place for a total 621 patient-weeks. Sensitivity to change was high (standardized response mean for LAI-P = 1.6). We found a significant association between LAI-P and m-PGA (P < 0.002 in all regression models performed). Sensitivity, specificity, and positive and negative predictive values were 0.93, 0.98, 0.88, and 0.99. Positive and negative likelihood ratios were 49 and 0.07, respectively. CONCLUSIONS: LAI-P has a high sensitivity to changes in lupus activity, a significant correlation with m-PGA, and high sensitivity, specificity, predictive values, and likelihood ratios for diagnosing SLE flares during pregnancy and the puerperium.

Adult↗

PubMed2005

Guanine and plasmid DNA binding of mono- and trinuclear fac-[Re(CO)3]+ complexes with amino acid ligands.

We have synthesized and fully characterized four new complexes comprising the fac-[Re(CO)3]+ moiety and the ligands NH3, L-proline (Pro), or N,N-dimethylglycine (dmGly). The reaction of [Re(H2O)3(CO)3]+ with the two amino acids gives trinuclear complexes of general formula [Re(L)(CO)3]3 (where L = amino acid). We have studied the in vitro behavior of these compounds with guanine and DNA in order to understand whether the cytotoxicity exhibited by certain rhenium complexes based on the fac-[Re(CO)3]+ core is due to the formation of nucleobase complexes and inter- or intrastrand links between DNA bases. We have performed model studies with guanine and studied the structural effects induced by different rhenium(I) tricarbonyl complexes on PhiX174 plasmid DNA by electrophoretic methods. Our results show that rhenium complexes with two available coordination sites interact with plasmid DNA to form a stable adduct that is likely to involve two bases.

Amino Acids↗

PubMed2006

Who refuses the diagnostic assessment for dementia in primary care?

OBJECTIVE: Early screening and detection of dementia in primary care remains controversial. At least half of the patients identified as cognitively impaired by screening instruments do not meet criteria for dementia and some patients refuse further evaluation following a positive screen. The aim of this study was to identify the characteristics of patients who refuse a clinical diagnostic assessment for dementia after screening. DESIGN: Cross sectional study. SETTING: Seven primary care practice centers in Indianapolis. PARTICIPANTS: Four hundred and thirty-four individuals aged 65 and older who screened positive for dementia with a mean age of 74.6, 67% women, and 68% African-American. MAIN OUTCOME MEASURE: Patients' acceptance of undergoing a dementia diagnostic assessment that included neuropsychological testing, caregiver interview, and medical chart review. RESULTS: Among patients with positive screening results for dementia, approximately half (47.7%) refused further assessment to confirm their screening results. In a bivariate analysis, possible factors associated with a higher probability of refusing dementia assessment were older age and better screening score. In a multiple logistic regression model, performing well on the temporal orientation of the screening instrument was associated with a higher probability of refusing diagnostic assessment for dementia (OR = 1.37; p = 0.001). Also, African-American patients aged 80 and older were more likely to refuse the diagnostic assessment than African-Americans less than 80 years of age (OR = 3.1, p < 0.001), while there was no significant age association for white patients (OR = 0.9, p = 0.728). CONCLUSIONS: Older primary care patients who perceived themselves as having no cognitive symptoms refused dementia diagnostic assessment despite their positive screening results. We must improve our understanding of the decision-making process driving patients' beliefs and behaviors about the benefits and risks of dementia screening and diagnosis before implementing any broad-based screening initiatives for dementia.

Black or African American↗

PubMed2025

Integration of Genetic Information to Improve Brain Age Gap Estimation Models in the UK Biobank.

Neurodegeneration occurs when the body's central nervous system becomes impaired as a person ages, which can happen at an accelerated pace. Neurodegeneration impairs quality of life, affecting essential functions, including memory and the ability to self-care. Genetics play an important role in neurodegeneration and longevity. Brain age gap estimation (BrainAGE) is a biomarker that quantifies the difference between a machine learning model-predicted biological age of the brain and the true chronological age for healthy subjects; however, a large portion of the variance remains unaccounted for in these models, attributed to individual differences. This study focuses on predicting the BrainAGE more accurately, aided by genetic information associated with neurodegeneration. To achieve this, a BrainAGE model was developed based on MRI measures, and then the associated genes were determined with a Genome-Wide Association Study. Subsequently, genetic information was incorporated into the models. The incorporation of genetic information yielded improvements in the model performances by 7% to 12%, showing that the incorporation of genetic information can notably reduce unexplained variance. This work helps to define new ways of determining persons susceptible to neurological aging decline and reveals genes for targeted precision medicine therapies.

Humans↗

PubMed2005

MDSIMAID: automatic parameter optimization in fast electrostatic algorithms.

MDSIMAID is a recommender system that optimizes parallel Particle Mesh Ewald (PME) and both sequential and parallel multigrid (MG) summation fast electrostatic solvers. MDSIMAID optimizes the running time or parallel scalability of these methods within a given error tolerance. MDSIMAID performs a run time constrained search on the parameter space of each method starting from semiempirical performance models. Recommended parameters are presented to the user. MDSIMAID's optimization of MG leads to configurations that are up to 14 times faster or 17 times more accurate than published recommendations. Optimization of PME can improve its parallel scalability, making it run twice as fast in parallel in our tests. MDSIMAID and its Python source code are accessible through a Web portal located at http://mdsimaid.cse.nd.edu.

Journal Article↗

PubMed2005

Structural elucidation and analysis of thermal degradation products of the Fusarium mycotoxin nivalenol.

The major class of mycotoxins produced by Fusarium moulds are trichothecenes, a large group of sesquiterpenes sharing the same basic chemical structure, a 12,13-epoxytrichothec-9-ene ring system. Their toxic effects range from causing diarrhoea, vomiting and gastro-intestinal inflammation to noncompetitive inhibition of the biosynthesis of proteins in eukaryotic cells. Trichothecenes in general are relatively stable compounds, their degradation is observed only at high temperatures and prolonged heating time. In order to investigate the stability of the trichothecene nivalenol (NIV) under food processing conditions such as cooking or baking, we performed model heating experiments and screened the residue for degradation products using gas chromatography-mass spectrometry (GC-MS). Heating of nivalenol, especially under mild alkaline conditions, gave a mixture of four compounds (norNIV A, norNIV B, norNIV C, and NIV lactone), which where isolated and identified by nuclear magnetic resonance (NMR) and MS experiments. Although their formation was also demonstrated in heating experiments with spiked flour samples, only norNIV B was detectable in a screening of several commercially available samples, possibly due to the very low contamination with nivalenol. Furthermore, cell culture experiments using immortalized human kidney epithelial (IHKE) cells showed that the four compounds are less cytotoxic (formazan dye cytotoxicity assay) compared to nivalenol. Whereas nivalenol revealed an EC50 at 0.9 micromol, all other compounds did not show any significant effect up to 100 micromol.

Cell Line, Transformed↗