Effects of Post-Anthesis High-Temperature Stress on Carbon Partitioning and Starch Biosynthesis in a Spring Wheat (Triticum aestivum L.) Adapted to Moderate Growth Temperatures.

This study investigates carbon partitioning in the developing endosperm of a European variety of spring wheat subjected to moderately elevated daytime temperatures (27°C/16°C d/night) from anthesis to grain maturity. Elevated daytime temperatures caused significant reductions in both fresh and dry weights and reduced the starch content of harvested grains compared to plants grown under a 20°C/16°C d/night regimen. Accelerated grain development caused by elevated temperatures was accounted for by representing plant development as thermal time (°C DPA). We examined the effects of high-temperature stress (HTS) on the uptake and partitioning of [U-14C]-sucrose supplied to isolated endosperms. HTS caused reduced sucrose uptake into developing endosperms from the second major grain-filling stage (approximately 260°C DPA) up to maturity. Enzymes involved in sucrose metabolism were unaffected by HTS, whereas key enzyme activities involved in endosperm starch deposition such as ADP-glucose pyrophosphorylase and soluble isoforms of starch synthase were sensitive to HTS throughout grain development. HTS caused a decrease in other major carbon sinks such as evolved CO2, ethanol-soluble material, cell walls and protein. Despite reductions in the labeling of carbon pools caused by HTS, the relative proportions of sucrose taken up by endosperm cells allocated to each cellular pool remain unchanged, except for evolved CO2, which increased under HTS and may reflect enhanced respiratory activity. The results of this study show that moderate temperature increases can cause significant yield reductions in some temperate wheat cultivars chiefly through three effects: reduced sucrose uptake by the endosperm, reduced starch synthesis and increased partitioning of carbon into evolved CO2.

A mathematical model for simulating the spread of a disease through a country divided into geographical regions with different population densities.

The SIR (susceptible-infectious-recovered) model is a well known method for predicting the number of people (or animals) in a population who become infected by and then recover from a disease. Modifications can include categories such people who have been exposed to the disease but are not yet infectious or those who die from the disease. However, the model has nearly always been applied to the entire population of a country or state but there is considerable observational evidence that diseases can spread at different rates in densely populated urban regions and sparsely populated rural areas. This work presents a new approach that applies a SIR type model to a country or state that has been divided into a number of geographical regions, and uses different infection rates in each region which depend on the population density in that region. Further, the model contains a simple matrix based method for simulating the movement of people between different regions. The model is applied to the spread of disease in the United Kingdom and the state of Rio Grande do Sul in Brazil.

Tuning the self-assembly of the bioactive dipeptide L-carnosine by incorporation of a bulky aromatic substituent.

The dipeptide L-carnosine has a number of important biological properties. Here, we explore the effect of attachment of a bulky hydrophobic aromatic unit, Fmoc [N-(fluorenyl-9-methoxycarbonyl)] on the self-assembly of Fmoc-L-carnosine, i.e., Fmoc-ß-alanine-histidine (Fmoc-ßAH). It is shown that Fmoc-ßAH forms well-defined amyloid fibrils containing ß sheets above a critical aggregation concentration, which is determined from pyrene and ThT fluorescence experiments. Twisted fibrils were imaged by cryogenic transmission electron microscopy. The zinc-binding properties of Fmoc-ßAH were investigated by FTIR and Raman spectroscopy since the formation of metal ion complexes with the histidine residue in carnosine is well-known, and important to its biological roles. Observed changes in the spectra may reflect differences in the packing of the Fmoc-dipeptides due to electrostatic interactions. Cryo-TEM shows that this leads to changes in the fibril morphology. Hydrogelation is also induced by addition of an appropriate concentration of zinc ions. Our work shows that the Fmoc motif can be employed to drive the self-assembly of carnosine into amyloid fibrils.

Degradation of lignified secondary cell walls of lucerne (Medicago sativa L.) by rumen fungi growing in methanogenic co-culture.

AIMS: To compare the abilities of the monocentric rumen fungi Neocallimastix frontalis, Piromyces communis and Caecomyces communis, growing in coculture with Methanobrevibacter smithii, to colonize and degrade lignified secondary cell walls of lucerne (alfalfa) hay. METHODS AND RESULTS: The cell walls of xylem cylinders isolated from stems of lucerne contained mostly xylans, cellulose and lignin together with a small proportion of pectic polysaccharides. All of these major components were removed during incubation with the three fungi, and differing cell wall polysaccharides were degraded to different extents. The greatest dry weight loss was found with N. frontalis and least with C. communis, and scanning electron microscopy revealed that these extensively colonized different cell types. C. communis specifically colonized secondary xylem fibres and showed much less degradation than N. frontalis and P. communis. CONCLUSIONS: Neocallimastix frontalis and P. communis were efficient degraders of the cell walls of lucerne xylem cylinders. Degradation occurred of pectic polysaccharides, xylan and cellulose. Loss of lignin from the xylem cylinders probably resulted from the cleavage of xylan releasing xylan-lignin complexes. SIGNIFICANCE AND IMPACT OF THE STUDY: Unlike rumen bacteria, the rumen fungi N. frontalis, P. communis and C. communis are able to degrade lignified secondary walls in lucerne stems. These fungi could improve forage utilization by ruminants and may have potential in the degradation of lignocellulosic biomass in the production of biofuels.

Influence of the solvent on the self-assembly of a modified amyloid beta peptide fragment. I. Morphological investigation.

The solvent-induced transition between self-assembled structures formed by the peptide AAKLVFF is studied via electron microscopy, light scattering, and spectroscopic techniques. The peptide is based on a core fragment of the amyloid beta-peptide, KLVFF, extended by two alanine residues. AAKLVFF exhibits distinct structures of twisted fibrils in water or nanotubes in methanol. For intermediate water/methanol compositions, these structures are disrupted and replaced by wide filamentous tapes that appear to be lateral aggregates of thin protofilaments. The orientation of the beta-strands in the twisted tapes or nanotubes can be deduced from X-ray diffraction on aligned stalks, as well as FT-IR experiments in transmission compared to attenuated total reflection. Strands are aligned perpendicular to the axis of the twisted fibrils or the nanotubes. The results are interpreted in light of recent results on the effect of competitive hydrogen bonding upon self-assembly in soft materials in water/methanol mixtures.

A Burton-Miller inverse boundary element method for near-field acoustic holography.

An inverse boundary element method based on the Burton-Miller integral equation is proposed for reconstructing the Neumann boundary data from pressure values on a conformal surface in the near-field of an arbitrary radiating object. The accuracy of the reconstruction is compared with that of a method based on the more commonly used Helmholtz integral equation. In particular, the behavior at characteristic frequencies, which are known to be problematic in the Helmholtz integral equation for the forward problem, is examined. The effect of regularization is considered, including the L-curve parameter selection method. Numerical computations are given for noisy data generated from an internal point source.

Degradation of forage chicory by ruminal fibrolytic bacteria.

AIMS: Determine the susceptibility of forage chicory (Cichorium intybus L.) to degradation by ruminal fibrolytic bacteria and measure the effects on cell-wall pectic polysaccharides. METHODS AND RESULTS: Large segments of fresh forage chicory were degraded in vitro by Lachnospira multiparus and Fibrobacter succinogenes, but not by Ruminococcus flavefaciens or Butyrivibrio hungatei. Cell-wall pectins were degraded extensively (95%) and rapidly by L. multiparus with a simultaneous release of uronic acids and the pectin-derived neutral monosaccharides arabinose, galactose and rhamnose. Fibrobacter succinogenes also degraded cell-wall pectins extensively, but at a slower rate than L. multiparus. Immunofluorescence microscopy using monoclonal antibodies revealed that, after incubation, homogalacturonans with both low and high degrees of methyl esterification were almost completely lost from walls of all cell types and from the middle lamella between cells. CONCLUSIONS: Only two of the four ruminal bacteria with pectinolytic activity degraded fresh chicory leaves, and each showed a different pattern of pectin breakdown. Degradation was greatest for F. succinogenes which also had cellulolytic activity. SIGNIFICANCE AND IMPACT OF THE STUDY: The finding of extensive removal of pectic polysaccharides from the middle lamella and the consequent decrease in particle size may explain the decreased rumination and the increased intake observed in ruminants grazing forage chicory.

Lack of late toxicity in patients treated with cisplatin-containing combination chemotherapy for metastatic testicular cancer.

To date, the prevalence and nature of the late toxicity of cisplatin-based combination chemotherapy for advanced testicular cancer has been poorly documented. Thirty men with a median age of 35 years (range, 23 to 63), who had undergone such treatment were assessed with detailed investigation to determine the type and frequency of chronic toxicity. The median follow-up from the time of commencement of chemotherapy was 75 months (range, 48 to 126). The most common late toxic effects were high tone hearing loss in 23 men (77%) and electrophysiological evidence of peripheral nerve damage in 15 (50%). Both the hearing and nerve abnormalities were predominantly asymptomatic. In addition, elevation of serum cholesterol, noted in 20 patients (67%), was significant (P = .014) when compared with a control population. Hyperuricemia was present in nine patients (30%). Only one patient, with other risk factors (smoking, family history), had evidence of ischaemic heart disease while 20% (all with a smoking history) had a diminished single breath diffusing capacity for carbon monoxide (DLCO). Cisplatin-based chemotherapy is relatively free of major long-term side effects and should not be withheld for fear of late toxicity.

The QRS scoring system for estimating myocardial infarct size: clinical, angiographic and prognostic correlations.

The relation between a QRS score derived from the routine electrocardiogram and left ventricular function was investigated in 181 patients after myocardial infarction. Patients with left ventricular hypertrophy and conduction defects were excluded. The QRS score correlated closely with the severity of wall motion abnormalities and left ventricular ejection fraction. The more severe the dyssynergy, the higher the QRS score (hypokinesia = 3.0; akinesia = 5.4; dyskinesia = 9.1). The left ventricular ejection fraction (percent) = 66 - (3.3 x QRS score) (correlation coefficient [r] = -0.81, probability [p] less than 0.001). With use of this regression equation, the QRS score predicted angiographic left ventricular ejection fraction to within 12% of the angiographic ejection fraction in 29 of 30 additional patients studied prospectively. The QRS score was also related to clinical functional class. The worse the clinical manifestation of left ventricular dysfunction, the higher the QRS score (Killip class I = 3.5; class II = 6.5; class III = 7.1). A QRS score greater than or equal to 7 had a specificity of 97% and a sensitivity of 59% for predicting an ejection fraction of less than 45%. Patients with a QRS score of 7 or greater had severe wall motion abnormalities, higher peak serum creatine kinase levels, higher prevalence of multivessel coronary disease, poor clinical functional class and an unfavorable outcome. The QRS score provides an inexpensive, clinically useful estimate of left ventricular function after myocardial infarction and can identify patients at high risk.

Patterns of left ventricular dilation during the six months after myocardial infarction.

Changes in left ventricular volume after a first myocardial infarction were studied in 50 patients. Serial radionuclide angiograms were obtained 48 h, 10 days and 1 and 6 months after infarction and left ventricular volume measured by a nongeometric method. Left ventricular dilation (greater than or equal to 20% increase in end-diastolic volume) occurred within 10 days of infarction in 11 patients, who had a mean volume increase of 34 +/- 15% (p = 0.002 versus 48 h) at 10 days and 61 +/- 43% (p = 0.01 versus 10 days) at 6 months. Ten other patients manifested left ventricular dilation between 10 days and 6 months with a lesser volume increase of 42 +/- 18% by 6 months. Among the 21 patients with ventricular dilation, progressive dilation (serial volume increases greater than or equal to 20% on two or more occasions) occurred in 8 patients, who all had a large anterior infarct. Mean volume increases at 10 days and 1 and 6 months were 27 +/- 20%, 49 +/- 40% (p = 0.03 versus 10 days) and 79 +/- 37% (p = 0.006 versus 1 month), respectively, in this group. In patients with progressive dilation, left ventricular ejection fraction decreased from 35 +/- 6% at 48 h to 24 +/- 10% at 1 month (p less than 0.001) and 27 +/- 10% (p = 0.006) at 6 months. Between 1 month and 2 years after infarction six patients died, of whom four had progressive dilation.(ABSTRACT TRUNCATED AT 250 WORDS)

Infarct artery perfusion and changes in left ventricular volume in the month after acute myocardial infarction.

The relation between perfusion of the infarct-related artery and changes in left ventricular volume and function during the month after a first myocardial infarction was examined in 40 patients who did not receive thrombolytic therapy. Infarct artery perfusion was documented at predischarge coronary angiography, and left ventricular volume was measured by nongeometric analysis of radionuclide angiograms performed within 48 hours of infarction and at 1 month. Left ventricular dilation (greater than or equal to 20% increase in volume) developed in 16 patients, whereas 5 patients had a decrease in left ventricular volume of greater than or equal to 20% by 1 month. Left ventricular dilation occurred in all 14 patients without perfusion of the infarct-related artery, compared with only 2 of 26 patients with perfusion of this artery due to subtotal occlusion or collateral vessels. All five patients whose left ventricular volume decreased by greater than or equal to 20% had a perfused infarct artery. Multiple linear regression analysis confirmed that the degree of perfusion of the infarct artery (partial r = 0.58, p = 0.001) was a more important predictor of volume change than was infarct size measured by peak creatine kinase (partial r = 0.30, p = 0.009) or QRS score (partial r = 0.20, p = 0.087). Left ventricular ejection fraction decreased from 0.38 +/- 0.10 to 0.30 +/- 0.16 (p = 0.05) in 11 patients with an anterior infarct and ventricular dilation; it increased from 0.45 +/- 0.10 to 0.62 +/- 0.07 (p = 0.02) in the 5 patients with a greater than or equal to 20% decrease in volume.(ABSTRACT TRUNCATED AT 250 WORDS)

Regional distribution of cardiac output at rest and during exercise in patients with exertional angina pectoris before and after nifedipine therapy.

The short-term effects of sublingual nifedipine (20 mg) on cardiac output and its distribution at rest and during exercise were evaluated by measurement of iliofemoral blood flow and cardiac output in 10 men with stable angina pectoris controlled by metoprolol. At rest, nifedipine significantly decreased iliofemoral vascular resistance from 294 +/- 36 to 165 +/- 29 dynes.s.cm-5.10(2) (p less than 0.01) and significantly increased iliofemoral blood flow from 0.34 +/- 0.04 to 0.57 +/- 0.11 liters/min (p less than 0.05). Systemic vascular resistance was reduced from 19 +/- 1 to 13 +/- 1 dynes.s.cm-5.10(2) (p less than 0.001) and cardiac output increased significantly from 4.7 +/- 0.3 to 5.8 +/- 0.5 liters/min (p less than 0.05). Mean arterial pressure decreased significantly and heart rate increased significantly. During maximal upright bicycle exercise during nifedipine therapy, iliofemoral vascular resistance and leg blood flow were unchanged compared with control (23 +/- 2 versus 21 +/- 3 dynes.s.cm-5.10(2) and 4.7 +/- 0.5 versus 4.4 +/- 0.6 liters/min), cardiac output remained significantly increased (12.8 +/- 0.8 to 15.2 +/- 1.2 liters/min, p less than 0.05) and systemic vascular resistance remained significantly reduced (8 +/- 1 to 5 +/- 1 dynes.s.cm-5.10(2); p less than 0.001). The proportion of cardiac output distributed to the working lower limbs was significantly reduced at all exercise levels. In summary, nifedipine caused a redistribution of cardiac output by vasodilating nonexercising vascular beds without altering the locally mediated vasodilation in exercising muscle. In patients with coronary artery disease given nifedipine therapy, an increase in exercise tolerance is due to relief of myocardial ischemia rather than to increased peripheral oxygen delivery.

Noninvasive assessment of acute effects of nifedipine on rest and exercise hemodynamics and cardiac function in patients with aortic regurgitation.

The acute effects of nifedipine (20 mg sublingually) on hemodynamics and cardiac function were studied at rest and during supine bicycle exercise in 20 patients with aortic regurgitation. At rest, heart rate increased by 13%, systemic vascular resistance decreased by 34% and regurgitant index decreased by 17%. The change in systemic vascular resistance was related to its initial rest level (r = 0.82, p less than 0.001) and to the changes in forward cardiac output (r = 0.58, p less than 0.01) and regurgitant index (r = 0.60, p less than 0.01). Left ventricular end-diastolic and end-systolic volumes, stroke volume and ejection fraction were unchanged, whereas right ventricular ejection fraction increased. During exercise, nifedipine administration further increased heart rate by 8% and decreased systemic vascular resistance by 19%. Both forward stroke volume and forward cardiac output increased, but total left ventricular stroke volume was unchanged, resulting in a significant decrease in regurgitant index. Although left ventricular end-diastolic volume was slightly decreased, end-systolic volume did not increase; thus, ejection fraction was higher than that during control exercise (p less than 0.01). Right ventricular ejection fraction increased further. In aortic regurgitation, the acute administration of nifedipine improved cardiac performance and reduced regurgitation at rest and during exercise as a result of afterload reduction and increased heart rate. Whether these beneficial effects will occur during long-term therapy requires further investigation.

Prognostic significance of a predischarge exercise test in risk stratification after unstable angina pectoris.

The prognostic significance of exercise testing was compared with clinical and electrocardiographic (ECG) variables in a prospective study of 107 patients with unstable angina discharged from the hospital on medical therapy. During a follow-up period of 12.8 +/- 1.4 months, 10 patients (9%) had a nonfatal myocardial infarction (n = 8) or died (n = 2) and 22 (20%) were readmitted with recurrent unstable angina. The relation between 20 clinical, ECG and exercise test variables and the risk of adverse outcome (death, nonfatal myocardial infarction or recurrent unstable angina) was analyzed using both univariate and multivariate (logistic regression) analysis. Univariate predictors of adverse outcome included diabetes mellitus, evolutionary T wave changes, T wave changes on the preexercise ECG and low maximal rate-pressure product during exercise. Independent predictors of adverse outcome in multivariate analysis included diabetes mellitus, evolutionary T wave changes after admission, rest pain during hospitalization, ST depression during exercise and low maximal rate-pressure product. A predictive model constructed using the regression equation and all independent predictors stratified patients into high and low risk groups (41% and 5% risk of adverse outcome, respectively). The result of a predischarge exercise test adds independent prognostic information to clinical and ECG data in medically treated patients with unstable angina and could be used in combination with clinical and ECG data to identify patients at risk of adverse events.

Hemodynamic and metabolic basis of impaired exercise tolerance in patients with severe left ventricular dysfunction.

Hemodynamic and metabolic changes were measured at rest and during exercise in 23 patients with chronic heart failure and in 6 control subjects. Exercise was limited by leg fatigue in both groups and capacity was 40% lower in the patients with failure. At rest, comparing patients with control subjects, heart rate and right atrial and pulmonary wedge pressure were higher; cardiac output, stroke volume and work indexes and ejection fraction were lower; mean arterial and right atrial pressure and systemic resistance were similar. During all phases of exercise in patients with heart failure, pulmonary wedge pressure and systemic vascular resistance were higher and pulmonary vascular resistance remained markedly elevated compared with values in control subjects. Cardiac output was lower in the patients with failure, but appeared to have the same physiologic distribution in both groups during exercise. Although arterial-femoral venous oxygen content difference was higher in patients with heart failure, this increase did not compensate for the reduced blood flow. Even though the maximal oxygen consumption was significantly reduced, femoral venous lactate and pH values were higher than values in control subjects, but femoral venous pH was similar in both groups at their respective levels of maximal exercise. Ejection fraction was lower in those with heart failure at rest and did not increase with exercise. Ventilation in relation to oxygen consumption was higher in patients with failure than in control subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of nifedipine on arterial oxygenation at rest and during exercise in patients with stable angina.

The effects of nifedipine on arterial oxygenation and hemodynamics were studied at rest and during bicycle exercise in 12 men (mean age 55 years, range 41 to 67) with stable exertional angina. The study was conducted double-blind on 2 days, 1 week apart, using a placebo-controlled crossover design. On each day, measurements at rest were made before and 20 minutes after 20 mg sublingual nifedipine or placebo and were followed by measurements made during exercise. Compared with placebo, nifedipine reduced mean arterial pressure, systemic vascular resistance and pulmonary vascular resistance, and increased heart rate and cardiac output at rest and during exercise. It did not alter mean pulmonary artery or pulmonary artery wedge pressures at rest, but decreased them during exercise. Nifedipine decreased arterial oxygen tension (PaO2) from 96 +/- 10 to 90 +/- 13 mm Hg (p less than 0.05) at rest and from 99 +/- 11 to 92 +/- 12 mm Hg (p less than 0.005) at submaximal exercise (33 +/- 21 W), but did not alter it (100 +/- 12 versus 100 +/- 16 mm Hg, p = NS) at maximal exercise (68 +/- 30 W). The reduction in PaO2 was not due to alveolar hypoventilation, because nifedipine did not alter arterial carbon dioxide tension, or to changes in mixed venous oxygen tension, which nifedipine increased at rest (39 +/- 2 versus 43 +/- 3 mm Hg, p less than 0.001) and during submaximal exercise (31 +/- 4 versus 33 +/- 4 mm Hg, p less than 0.03) and maximal exercise (27 +/- 3 versus 31 +/- 3 mm Hg, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Prognostic value of ventricular arrhythmias associated with treadmill exercise testing in patients studied with cardiac catheterization for suspected ischemic heart disease.

The prognostic information provided by ventricular arrhythmias associated with treadmill exercise testing was evaluated in 1,293 consecutive nonsurgically treated patients undergoing an exercise test within 6 weeks of cardiac catheterization. The 236 patients with simple ventricular arrhythmias (at least one premature ventricular complex, but without paired complexes or ventricular tachycardia) had a higher prevalence of significant coronary artery disease (57 versus 44%), three vessel disease (31 versus 17%) and abnormal left ventricular function (43 versus 24%) than did patients without ventricular arrhythmias. Patients with paired complexes or ventricular tachycardia had an even higher prevalence of significant coronary artery disease (75%), three vessel disease (39%) and abnormal left ventricular function (54%). In the 620 patients with significant coronary artery disease, patients with paired complexes or ventricular tachycardia had a lower 3 year survival rate (75%) than did patients with simple ventricular arrhythmias (83%) and patients with no ventricular arrhythmias (90%). Ventricular arrhythmias were found to add independent prognostic information to the noninvasive evaluation, including history, physical examination, chest roentgenogram, electrocardiogram and other exercise test variables (p = 0.03). Ventricular arrhythmias made no independent contribution once the cardiac catheterization data were known. In patients without significant coronary artery disease, no relation between ventricular arrhythmias and survival was found.

Solid-State 13C Nuclear Magnetic Resonance Characterization of Cellulose in the Cell Walls of Arabidopsis thaliana Leaves.

Solid-state 13C nuclear magnetic resonance was used to characterize the molecular ordering of cellulose in a cell-wall preparation containing mostly primary walls obtained from the leaves of Arabidopsis thaliana. Proton and 13C spin relaxation time constants showed that the cellulose was in a crystalline rather than a paracrystalline state or amorphous state. Cellulose chains were distributed between the interiors (40%) and surfaces (60%) of crystallites, which is consistent with crystallite cross-sectional dimensions of about 3 nm. Digital resolution enhancement revealed signals indicative of triclinic and monoclinic crystalline forms of cellulose mixed in similar proportions. Of the five nuclear spin relaxation processes used, proton rotating-frame relaxation provided the clearest distinction between cellulose and other cell-wall components for purposes of editing solid-state 13C nuclear magnetic resonance spectra.

The effect of alternate substrates and substrate concentration on the antibody-mediated inhibition of horseradish peroxidase.

Inhibition of the catalytic activity of horseradish peroxidase by rabbit antisera was measured using alternate enzyme substrates. The same general inhibition curve patterns were obtained regardless of the electron donor or hydroperoxide used. In all cases typical biphasic inhibition patterns were found and complete inhibition of enzyme activity was never observed. Measurement of the degree of inhibition as a function of substrate concn revealed a dependence of anticatalytic activity on hydroperoxide concn. As the concn of hydrogen peroxide in the assay mixture increased, there was a corresponding increase in the inhibition observed. On the other hand, the degree of inhibition was not dependent on the concn of electron donor (dianisidine) in the assay mixture. Spectrophotometric experiments with an electron donor analogue demonstrated that antibodies do not inhibit peroxidase activity by excluding electron donor molecules from enzyme binding sites. The results have suggested possible mechanisms for the antibody-mediated inhibition of peroxidase activity.

Severe hepatic dysfunction is associated with venous thromboembolic events in phase 1 clinical trials.

INTRODUCTION: Venous thromboembolic events (VTEs) are a significant cause of death in patients with cancer. The incidence of VTE is not well characterized in early phase clinical trials of novel antineoplastic agents, or in hepatic dysfunction studies designed for patients with varying degrees of liver test abnormalities. We compared the incidences of VTE in phase 1 clinical trials (P1CTs) and hepatic dysfunction trials (HDCTs) sponsored by the Cancer Therapy Evaluation Program of the National Cancer Institute (NCI) of the United States. MATERIALS & METHODS: We reviewed individual patient records of 1841 subjects for symptomatic VTE diagnosed while on study: 1328 subjects on 42 P1CTs, and 513 subjects on 9 HDCTs. The NCI's Organ Dysfunction Working Group definitions were used to categorize patients. The incidences of VTEs between patients were compared by the Chi square test. Confounders were evaluated with the Cochran-Mantel-Haenszel method. RESULTS & CONCLUSIONS: There were 43 VTEs identified among all subjects (2.3%). There were significantly more VTE observed in the subjects on P1CTs (n=38, 2.9%) than in the subjects on HDCTs (n=5, 1.0%; RR 0.341, 95% 0.13-0.86, p=0.015). For patients on HDCTs, those with severe dysfunction had a high incidence of VTE (RR 10.5 (1.12-93.6), p=0.021) that remained significant in a multivariate model. VTEs were observed less frequently in patients who were enrolled in HDCT than those who were enrolled in P1CT; however, patients with severe hepatic dysfunction were more likely to experience VTE. Severe liver test abnormalities may not be protective against VTE in patients with malignancies receiving chemotherapy.