Observing and quantifying airflows in the infection control of aerosol- and airborne-transmitted diseases: an overview of approaches

With concerns about the potential for the aerosol and airborne transmission of infectious agents, particularly influenza, more attention is being focused on the effectiveness of infection control procedures to prevent hospital-acquired infections by this route. More recently a number of different techniques have been applied to examine the temporal-spatial information about the airflow patterns and the movement of related, suspended material within this air in a hospital setting. Closer collaboration with engineers has allowed clinical microbiologists, virologists and infection control teams to assess the effectiveness of hospital isolation and ventilation facilities. The characteristics of human respiratory activities have also been investigated using some familiar engineering techniques. Such studies aim to enhance the effectiveness of such preventive measures and have included experiments with human-like mannequins using various tracer gas/particle techniques, real human volunteers with real-time non-invasive Schlieren imaging, numerical modelling using computational fluid dynamics, and small scale physical analogues with water. This article outlines each of these techniques in a non-technical manner, suitable for a clinical readership without specialist airflow or engineering knowledge.

Does bladder urothelial cancer behave differently in young patients?

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Background: From 2000 to 2008, the incidence of bladder urothelial cancer in the young adults was diagnosed at an increasing trend at the Tongji Hospital, China. To investigate whether bladder urothelial cancer in patients under the age of 40 years behaves significantly differently from the bladder urothelial cancer in elder patients.

Methods: From 1994 to 2008, the records of 4,568 patients with pathological diagnosis of bladder urothelial cancer presented to the Tongji Hospital were retrospectively reviewed. 82 patients were younger than 40 at the time of diagnosis. The clinicopathologic parameters were compared between this group and a serial of 164 older patients during the same time period. The Kaplan-Meier and Cox regression analyses were performed for the survival analysis.

Results: 2.05% of patients with pathological diagnosis of bladder urothelial cancer presented to the Tongji Hospital were younger than 40 years (median age 32.93). Compared to the older group, young adults group had a lower sex ratio (male-to-female ratio, 3.4:1vs.6.5:1, p<0.05); much less likely with advanced stages (the percentage of invasive tumor, i.e., T1 or above, 28.1% vs. 52.4%, p<0.01); less with a high grade (the percentage of high grade tumor, 14.6% vs. 22.6%, p<0.05); lower recurrence rate (23.2% vs. 39.6%, p<0.05); less with big tumor size (the percent of tumor size greater than 3 cm, 18.3% vs. 22.0%, p<0.05); and less with multifocal (12.2% vs. 50.6%, p<0.01). Kaplan-Meier method and the log-rank test showed a significantly better cancer specific and overall survival for the group of young patients (p<0.01). The multivariate Cox regression analyses showed the following criteria were independent prognostic factors of overall survival: bladder tumor multiplicity, size greater than 3 cm, T2 or above stage, and high grade.

Conclusions: Despite an increasing trend of diagnosis, both the pathologic features and clinical outcomes were significantly better in the young patients with bladder urothelial cancer when compared to their elderly counterparts. These findings suggested that more consevertive management approaches may be warranted for this group of patients even under the circumstances of extensive bladder involvement.

No significant financial relationships to disclose.

Arterial stiffness and asymptomatic intracranial large arterial stenosis and calcification in hypertensive chinese

BACKGROUND

Intracranial large artery disease (ICLAD), such as stenosis and calcification, is common in Chinese patients with stroke. However, little is known about ICLAD and its association with large arterial stiffness in hypertensive patients.

METHODS

We recruited 270 (mean age 61.0 years, 45.6% male) untreated hypertensive patients without stroke from a community in Shanghai, China. ICLAD was detected by computerized tomographic angiography (CTA). Carotid-femoral pulse wave velocity (cf-PWV), office, and 24-h ambulatory pulse pressure (PP) as well as ambulatory arterial stiffness index (AASI) were determined as the measures of arterial stiffness.

RESULTS

Among all participants, 26 (9.6%) had concurrent intracranial arterial stenosis and calcification, 11 (4.1%) stenosis only, and 71 (26.3%) calcifications only. After adjustment for age, mean arterial pressure, and other covariables, there was significant difference in cf-PWV (13.1 vs. 13.7 vs. 15.0 m/s; P = 0.0015) and 24-h PP (46.7 vs. 48.8 vs. 55.7 mm Hg; P = 0.0007) between patients with normal vessels (n = 162), with stenosis or calcification (n = 82), and with both lesions (n = 26). Multiple ordinal logistic regression analyses showed that both cf-PWV and 24-h PP were independently associated with ICLAD. Odds ratios (95% confidence interval (CI)) of ICLAD after multivariable and mutually adjustment were 1.51 (1.09-2.10) and 1.46 (1.06-2.01) for 1-s.d. increase in cf-PWV and 24-h PP, respectively. No significant association (P ≥ 0.10) with AASI or office PP was observed in multivariable analysis.

CONCLUSION

Increased arterial stiffness was independently associated with ICLAD. cf-PWV and 24-h PP might be useful in identifying those more likely to have ICLAD among hypertensive patients.

The farther from town the lower the blood pressure: report from rural Yunnan province

BACKGROUND

Hypertension (HTN) is a major cause of death in Chinese farmers. Remoteness from population centers may independently affect HTN prevalence and severity.

METHODS

We used random cluster sampling to select 27 villages in Yunnan province, China. Within each village, we randomly selected 50-80 men and women between the ages of 50 and 70 years. A total of 1,177 participants underwent interviews and blood pressure (BP) measurement. We evaluated the relationship between BP and distance of the participants' village from the town and county centers with and without adjustment for covariates.

RESULTS

There was a significant (P < 0.001) inverse relationship between BP and distance from populations centers. For every 10 km from the town center, the mean systolic BP (SBP) in the village decreased by 1.2 mm Hg and the mean diastolic by 0.5 mm Hg. After adjustment for age, gender, ethnicity, body mass index, smoking, and drinking, we found that SBP decreased by 1.8 mm Hg (P = 0.03) and diastolic BP by 1.0 mm Hg (P = 0.02) for every 10 km distance from the town center.

CONCLUSIONS

HTN prevalence and severity are significantly linked to distance from population centers in rural Chinese farmers. The farther a farmer's village is from larger population centers, the greater is the probability that his/her BP will be normal. This relationship is independent of age, gender, ethnicity, body mass index, smoking, and alcohol use. Strategies in addressing HTN in rural regions should take account of this geographic dependence on distance from population centers.

DAB389 EGF for the treatment of superficial urothelial cancer

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Background: Intravesical BCG has remained the standard treatment for superficial bladder cancer for decades, despite frequent recurrences after its use. Toxic fusion proteins are a novel class of agents containing both a targeting and a treatment component; correspondingly, DAB389EGF contains an EGF and a diphtheria element, thereby targeting any cell expressing EGFR. Notably, the normal urothelium has little or no luminal EGFR expression in contrast to urothelial cancers, which frequently overexpress EGFR.

Methods: DAB389EGF was tested in vitro to determine the effect of DAB389EGF on cell viability in culture. Tests of clonogenicity were performed by treating plated cells for 2 hours and following colony counts over 14 days. DAB389EGF was tested in an orthotopic murine model of bladder cancer with implanted HTB9 cells modified to express luciferase. DAB389EGF was administered intravesically via catheterization of the murine bladder and held in place for 2 hours with a temporary suture to close the urethra. Treatments were continued twice weekly for 2 weeks, with DT-GMCSF used as a control.

Results: Treatment with DAB389EGF yielded IC50's ranging from 0.5 to 15.7 ng/ml in 8 tested bladder cancer cell lines, but the IC50 was > 500ng/ml in the EGFR- negative H520 control cell line. A single 2-hour exposure to DAB389EGF (50ng/ml) decreased colony formation in all of the bladder cancer cell lines, with complete suppression in HT1376 and T24 cells. In the animal model, luciferase activity was lost in 5 of 6 mice treated with DAB389EGF, versus 1 of 6 mice treated with control. After the 2 week treatment period, histological assessment of the treated mice was undertaken and was consistent with the luciferase findings. FISH was used to detect human or murine-originated cells in order to confirm the presence or absence of xenograft tissue histologically.

Conclusions: Targeted-toxin fusion proteins represent a novel treatment approach for superficial bladder cancer. By capitalizing on the differential expression of EGFR between cancerous and normal urothelium, DAB389EGF selectively targets bladder cancer cells. Preliminary animal studies support the efficacy and tolerability of this approach with additionally animal work currently underway.

No significant financial relationships to disclose.

An Investigation of Buried Layer Formation by 40keV Oxygen Implantation Into Silicon

Device grade single crystal <100> silicon wafers have been implanted with 40keV oxygen ions over a dose range of 2×1017 to 8×1017/cm2 at a temperature of 5507±10°C. The specimens have been analyzed, both before and after high-temperature annealing at 1320°C for six hours, using SIMS, RBS, and TEM. During implantation a continuous buried SiO2 layer forms when the dose after which the buried SiO2 layer grows primarily toward the surface. After annealing samples implanted with the doses of both 2×1017 and 3×1017/cm2 it was observed that a defective SIMOX like structure was formed. Implanting with a dose of 4×1017/cm2 results in pit formation in the silicon overlayer. For the sample implanted with a higher dose of 5×1017/cm2, a non-continuous poly-crystalline silicon “overlayer” was formed. It would thus appear that when a single step implantation route is chosen, there is a dose (or layer thickness) limit for the production of a thin film SIMOX structure.

Recent Advances in Solid Hydrogen Storage Systems

Hydrogen energy offers great promise as an energy alternative. Hydrogen technologies can reduce and eliminate the release of carbon dioxide from fossil-fuel combustion, the main cause of global warming. One of the main challenges is hydrogen storage. Storing hydrogen in the solid-state hydride form holds a volumetric advantage over compressed and liquid hydrogen states. Solid hydrogen storage systems also have features of low-pressure operation, compactness, safety, tailorable delivery pressure, excellent absorption /desorption kinetics, modular design for easy scalability, and long cycle life.

In this paper, solid hydrogen storage systems (such as portable power canisters, lightweight fiber wrapped vessels, and aluminum tubular vessels, developed by Texaco Ovonic Hydrogen Systems LLC) will be discussed. A system of four canisters each storing approximately 80 grams of reversible hydrogen is shown to run a 1 kW PEM fuel cell for more than 247 minutes at full power. Canisters show no plastic deformation after more than 500 charge/discharge cycles. The measured strain on canister surfaces indicates that DOT stress limits are not exceeded. The canisters are in the early commercialization stage for uninterrupted power supply (UPS) and auxiliary power unit (APU) applications.

A lightweight fiber-wrapped vessel engineered with metal hydride and internal heat exchanger is being developed for onboard applications. At the system level, the vessel has a volumetric energy density of 50 grams of hydrogen per liter and a gravimetric density of 1.6 wt.%. The vessel is capable of storing 3 kg of hydrogen with a fast refueling capability. Ninety percent of the storable hydrogen can be refueled in 10 minutes at 1500 psig. The vessel can easily release the hydrogen at a rate of 350 slpm at 70°C.

Aluminum tubular vessels are being designed and tested for bulk storage and infrastructure applications including stationary power, hydrogen shipment and hydrogen service stations. The tubular vessel dimensions may be designed for specific applications. For example, a tubular vessel 6 inches in diameter and 62 inches in length can store up to 1 kg of hydrogen.

Role of vascular endothelial growth factor in protection of intrahepatic cholangiocytes mediated by hypoxic preconditioning after liver transplantation in rats

OBJECTIVE

To investigate the effect on intrahepatic cholangiocytes mediated by hypoxic preconditioning (HP) after liver transplantation and the role of vascular endothelial growth factor (VEGF).

MATERIALS AND METHODS

This experiment was based on a model of rat orthotopic liver autotransplantation. Sprague-Dawley rats were randomly divided into 3 groups: normal control, autotransplantation (AT), and HP. The HP group was subjected to 8% oxygen atmosphere for 90 minutes before surgery. At 6, 12, 24, and 48 hours after autotransplantation, the rats were killed for testing .Serum total bilirubin, direct bilirubin, and alkaline phosphatase concentrations were determined. The microstructure of cholangiocytes and the ultramicrostructure of cholangioles were determined. Immunohistochemistry was used to detect the expression of VEGF and the proliferation rate of cholangiocytes.

RESULTS

Total bilirubin, direct bilirubin, and alkaline phosphatase concentrations in the AT group increased considerably more than in the HP group during the entire interval (P < .05). Light microscopy demonstrated that the microstructure of cholangiocytes in the AT group was damaged more seriously than in the HP group. At transmission electron microscopy, the ultramicrostructure of cholangioles was changed more obviously than in the HP group. The expression of VEGF on cholangiocytes and the proliferation rate of cholangiocytes were higher in the HP group than in the AT group over the entire experiment (P < .05).

CONCLUSION

Hypoxic preconditioning has a protective effect on cholangiocytes after liver autotransplantation. The mechanism may be related to HP-induced overexpression of VEGF on cholangiocytes.

Clinical analysis of living related renal transplantation with donors older than 50 years in China

OBJECTIVE

The objective of this study was to investigate whether kidney grafts from living related donors older than 50 years were safe for the donors and recipients in the long term.

METHODS

One hundred seven living related donor kidney transplantations were performed in our center from April 1994 to December 2007. No prisoners or organs from prisoners were used in the collection of these data. Donors were divided into 2 groups: >50 years of age (range, 51-78 years), designated as the study group, and ≤50 years of age (range, 21-50 years), designated as the control groups. The mean time of follow-up was 49 months (range, 12-180 months). Clinical data were compared, including donor serum creatinine (Scr) levels, glomerular filtration rates (GFR) before and after the procedures operative complications, and postoperative short-term and long-term recovery of renal function in recipients as well as their complications and recipient and kidney survivals.

RESULTS

All operations were successfully performed. Before the operation, the mean Scr and GFR were 82.16 ± 10.86 umol/L and 85.82 ± 6.26 mL/min, respectively, in the study group versus 78.66 ± 10.41 umol/L and 88.74 ± 9.44 mL/min, respectively, in the control group. There were no significant differences in mean Scr or GFR values between the groups at various preoperative or postoperative times (P > .05). No severe perioperative complications occurred, and no subsequent renal function failure was observed upon long-term follow-up of donors in the 2 groups. Comparisons of recipient age, gender ratio, duration on dialysis, HLA matches, cold/warm ischemia times, and immunosuppression therapy showed a correlations between the 2 groups. Mean Scr levels of recipients, which were compared from 1 week to 3 years following surgery, were slightly higher among the control than the study group, but the difference was not significant (P > .05). There were no significant differences between the study and control groups in 1-,3-,5-, and 8-year recipient/graft survival rates (P > .05).

CONCLUSIONS

Long-term follow-up showed that transplantations using grafts from donors older than 50 years of age yielded similar results to those with younger donors.

Refined mapping of the Escherichia coli F4ab/F4ac receptor gene(s) on pig chromosome 13

Enterotoxigenic Escherichia coli expressing F4 fimbriae is the major cause of diarrhoea in neonatal and post-weaning piglets. Previous studies have revealed that the loci controlling the F4ab/F4ac receptors are located on SSC13q41, between markers SW207 and S0283. In this study, we refined their positions in a two generation population containing 366 piglets of three breeds (Large White, Landrace, and Songliao Black). Nine microsatellite markers within this region were selected from the MARC (U.S. Meat Animal Research Center) porcine linkage map, and the pedigree disequilibrium test was employed for fine-mapping. The F4abR gene was located in the interval between S0283 and SW1833, a 4.8-cM region, and the F4acR gene was located in the interval between S0283 and SW1876, a 1.6-cM region. Our results also suggest that the F4ab/F4ac receptors might be controlled by two different but closely linked loci. The results of microsatellite-based haplotype analysis in the corresponding region show that some specific haplotypes were overwhelmingly present in the adhesive or non-adhesive animals, indicating that there are mutations within the identified regions that are strongly associated with the F4ab/ac phenotypes.

Photoluminescence and Sims Studies of Hydrogen Passivation of Mg-Doped P-Type Gallium Nitride

The effects of hydrogen passivation in MOCVD grown Mg doped p-type GaN were studied using low temperature (5K) photoluminescence (PL) and secondary-ion-mass spectroscopy (SIMS). GaN films with different Mg doping level were annealed at 700° C in N2 ambient with different annealing times. The SIMS results indicate that the hydrogen concentration increases with increasing Mg doping level in the as-grown Mg:GaN film. After 20 minutes of annealing, most of the hydrogen escapes from the film. The 3.455 eV PL peak before annealing and the 3.446 eV peak after annealing found in the Mg doped samples were attributed to the exciton bound to the Mg-H complex and to the Mg acceptor, respectively. The shift of the bound exciton peak to higher energy (3.465 eV) in the lightly doped sample is due to an effective n-type compensation associated with an annealing-induced increase in the nitrogen vacancies. In heavily doped Mg:GaN, the decreases in the integrated PL intensity after 700° C annealing may be associated with the hydrogen depassivation of nonradiative recombination centers in the film. The increase of PL intensity in the lightly doped sample after annealing is attributed to the reduction of defects by the annealing process.

HEF1, a novel target of Wnt signaling, promotes colonic cell migration and cancer progression

Misregulation of the canonical Wnt/β-catenin pathway and aberrant activation of Wnt signaling target genes are common in colorectal cancer (CRC) and contribute to cancer progression. Altered expression of human enhancer of filamentation 1 (HEF1; also known as NEDD9 or Cas-L) has been implicated in progression of melanoma, breast, and CRC. However, the regulation of HEF1 and the role of HEF1 in CRC tumorigenesis are not fully understood. We here identify HEF1 as a novel Wnt signaling target. The expression of HEF1 was upregulated by Wnt-3a, β-catenin, and Dvl2 in a dose-dependent manner, and was suppressed following β-catenin downregulation by shRNA. In addition, elevated HEF1 mRNA and protein levels were observed in CRC cell lines and primary tumor tissues, as well as in the colon and adenoma polyps of Apc(Min/+) mice. Moreover, HEF1 levels in human colorectal tumor tissues increased with the tumor grade. Chromatin immunoprecipitation (ChIP) assays and promoter analyses revealed three functional T-cell factor (TCF)-binding sites in the promoter of HEF1 responsible for HEF1 induction by Wnt signaling. Ectopic expression of HEF1 increased cell proliferation and colony formation, while downregulation of HEF1 in SW480 cells by shRNA had the opposite effects and inhibited the xenograft tumor growth. Furthermore, overexpression of HEF1 in SW480 cells promoted cell migration and invasion. Together, our results determined a novel role of HEF1 as a mediator of the canonical Wnt/β-catenin signaling pathway for cell proliferation, migration, and tumorigenesis, as well as an important player in colorectal tumorigenesis and progression. HEF1 may represent an attractive candidate for drug targeting in CRC.

Measurement of the parity-violating longitudinal single-spin asymmetry for W± boson production in polarized proton-proton collisions at sqrt[s] = 500 GeV

We report the first measurement of the parity-violating single-spin asymmetries for midrapidity decay positrons and electrons from W+ and W- boson production in longitudinally polarized proton-proton collisions at sqrt[s] = 500 GeV by the STAR experiment at RHIC. The measured asymmetries, A(L)(W+) = -0.27 ± 0.10(stat.) ± 0.02(syst.) ± 0.03(norm.) and A(L)(W-) = 0.14 ± 0.19(stat.) ± 0.02(syst.) ± 0.01(norm.), are consistent with theory predictions, which are large and of opposite sign. These predictions are based on polarized quark and antiquark distribution functions constrained by polarized deep-inelastic scattering measurements.

GaN-Based MSM uv Photodetectors

Results obtained from interdigital metal-semiconductor-metal (MSM) type of GaN based UV photodetectors are presented. MSM devices were fabricated using two types of GaN; high-resistive GaN and Mg doped GaN. For the high-resistive GaN detector, the lowest dark current is ∼0.1 nA and the UV responsivity of the device was about 460 AAV at a DC bias of 30 V. The Mg doped GaN exhibited large gains, 1150 A/W at 2.0 V, but at much higher dark currents, 400 nA. The high gain in this device is not well understood but was attributed to an ‘avalanche’ effect and is under investigation. It was found that the surface plasma treatment plays an important role in the device performance. After an appropriate plasma treatment the detectors showed higher responsivity with lower dark current.

Development of High-Efficiency Zn2SiO4:Mn Thin Films for Flat Panel Cathodoluminescent Displays

Zn2SiO4:Mn thin films were deposited and studied as thin film phosphors for flat panel cathodoluminescent displays. Crystallized films with improved electrical conductivity were obtained after conventional and rapid thermal annealings in a N2 environment at 850Xy11100 °C for 0.25 to 60 minutes. A maximum cathodoluminescent efficiency of 1.3 Lm/W was achieved under dc excitation at 1500 volts. The luminescent emission from these thin films was peaked around 525 nm. The decay time of these films was controlled in the range of 2 to 10 ms by varying the deposition and annealing parameters. The fast response time of these thin films overcomes the long decay limitation of the Zn2SiO4:Mn powder phosphor in practical display applications.

Approach to high-frequency, cavity-enhanced Faraday rotation in fluids

Recent work demonstrating detection of nuclear spin magnetization via Faraday rotation in transparent fluids promises novel opportunities for magnetic resonance imaging and spectroscopy. Unfortunately, low sensitivity is a serious concern. With this motivation in mind, we explore the use of an optical cavity to augment the Faraday rotation experienced by a linearly polarized beam traversing a sample fluid. Relying on a setup that affords reduced sample size and high-frequency modulation, we demonstrate amplification of regular (i.e., nonnuclear) Faraday rotation of order 20. Extensions of the present methodology that take into account the geometric constraints imposed by a high-field magnet may open the way to high-sensitivity, optically-detected magnetic resonance in the liquid state.

Technological Development for Commercialization of Amorphous Silicon Based Multijunction Modules

Some of the significant steps in technological development for large-scale commercialization of amorphous silicon (a-Si:H) based multijunction photovoltaic modules are presented. These developments are establishing a high quality baseline process for manufacturing large-area ( ˜ 8 ft2) a-Si:H/a-SiGe:H tandem junction modules with improved stabilized conversion efficiency, throughput, yield, and reduced materials usage.

Mechanism of Cu removal during CMP in H2O2-glycine based slurries

Hydroxyl radical generation has been observed during Cu CMP using hydrogen peroxide-glycine based slurries. While the Cu dissolution/polish rates increased with increasing glycine concentration, the copper dissolution rate decreased with increasing peroxide concentration indicating the occurrence of both dissolution and passive film formation during CMP. This is further confirmed by both in situ and ex situ electrochemical experiments.

Expressions of BAFF/BAFF receptors and their correlation with disease activity in Chinese SLE patients

B-cell activating factor belonging to tumour necrosis factor family (BAFF) is essential for B-cell survival and function through interaction with its receptors BAFF receptor 3 (BR3), B-cell maturation antigen (BCMA) and/or transmembrane activator and calcium modulator and cyclophilin ligand interactor (TACI), though BCMA and/or TACI can also bind to a proliferation-inducing ligand (APRIL). We evaluate the correlation of the expressions of these ligands/receptors with different clinical manifestations of systemic lupus erythematosus (SLE). Levels of BAFF and APRIL in plasma from 73 SLE patients were determined by enzyme-linked immunosorbent assay. Expressions of BR3, TACI and BCMA on CD19+ B cells were detected by flow cytometry. Clinical data were collected and disease activity was evaluated using SLEDAI-2000. SLE patients had elevated BAFF and APRIL levels in their plasma. BAFF levels correlated positively with SLEDAI while negatively with the BR3 protein expression on CD19+ B cells (p < .05). The detected BR3 protein expression in SLE patients was reduced on CD19+IgD+CD27-, CD19+IgD+CD27+ as well as CD19+IgD-CD27+ B cells compared to the counterparts of healthy controls (p < .001), whereas SLE patients did not differ from healthy controls in BR3 mRNA levels. In untreated new-onset patients, the expression rate of BR3 on CD19+ B cells correlated negatively with SLEDAI (p < .05). Elevation of BAFF and reduction of BR3 on CD19+ B cells were more obvious in those with lupus nephritis (LN, p < .05). TACI expression on CD19+ B cells was up-regulated only in those subjects with LN (p < .05). Elevated plasma BAFF and reduced BR3 protein expression on peripheral B cells could act as biomarkers for active disease in SLE patients. High expression of TACI may indicate the occurrence of LN.

Rapid 5-fluorouracil plasma quantification by immunoassay: Validation with FOLFOX6 clinical samples

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Background: 5-fluorouracil (5-FU) is one of the most widely used chemotherapy agents in the treatment of colorectal cancer. Studies over the last 30 years have demonstrated wide pharmacokinetic variability of 5-FU which can lead to undue toxicity and suboptimal treatment. Recent clinical studies have demonstrated that managing plasma 5-FU levels and adjusting doses to target steady state concentrations effectively minimizes toxicity and improves outcome.

Methods: An existing immunoassay using a novel antibody to 5-FU was modified to directly quantify 5-FU in patient plasma samples without any sample pretreatment. The assay was adapted to Beckman Coulter AU analyzers and to Roche COBAS c 111 analyzer. Method comparison to LC-MS/MS, limit of detection (LoD), lower limit of quantitation (LLoQ), precision, and linearity of the assay were evaluated. The assay was also validated by testing samples of patients being treated by modified FOLFOX6 from an on-going clinical trial ( NCT00943137 ).

Results: The modified immunoassay was confirmed to have a linear reportable range from 85 to 18,000ng/mL and a LoD of 52ng/mL. The immunoassay was established to have good precision (CV<6%) around the medical decision points for FOLFOX and FOLFIRI regimens. Method comparison of the immunoassay obtained by testing 58 clinical samples from patients under 5-FU treatment provides excellent correlation to LC- MS/MS: Deming slope 1 ± 0.05, R > 0.98. Another 82 samples of patients on modified FOLFOX6 regimen from clinical trial (( NCT00943137 ) were tested using the immunoassay and range of these sample were reported to be from 95 to 2,970 ng/mL.

Conclusions: The assay provided the performance required to rapidly quantify 5-FU plasma concentrations. It was fast (time to 1st result < 10 minutes), precise, correlated well to a physical method, required only 100uL sample on the analyzer and 7ul for actual testing per assay, and was easily adapted to a variety of clinical analyzers. Clinical and pharmacokinetic laboratories could use this assay to introduce an evidence-based approach to optimize 5-FU dosing that would have higher throughput, simpler methodology, and require less labor, space or expense than the physical methods.

[Table: see text]