Comparison of the immunogenicity of recombinant VP2 and VP3 of infectious pancreatic necrosis virus and marine birnavirus

Recombinant proteins of truncated viral protein-2 (VP2) (aa 79-359) and VP3 of infectious pancreatic necrosis virus (IPNV) and marine birnavirus (MABV) were expressed in E. coli and their immunogenicities in fish were investigated. The recombinant proteins from IPNV were used to immunize rainbow trout and those from MABV to immunize flounder. The sera from the immunized fishes were assayed for antibody by ELISA and a neutralization test. Both the recombinant VP2 and VP3 produced antibodies in fish but the VP3 antibody titers were higher than that of the VP2 of IPNV and MABV. These results indicate that the recombinant VP3 is more immunogenic than the recombinant VP2.

Role of NADP+-dependent isocitrate dehydrogenase (NADP+-ICDH) on cellular defence against oxidative injury by gamma-rays

PURPOSE

To investigate the regulation of NADPH-producing isocitrate dehydrogenase (ICDH) in cytosol (IDPc) and mitochondria (IDPm) upon gamma-ray irradiation, and the roles of IDPc and IDPm in the protection against cellular damage induced by gamma-ray irradiation.

MATERIALS AND METHODS

Changes of IDPc and IDPm proteins upon gamma-ray irradiation to NIH3T3 cells were analysed by immunoblotting. To increase or decrease the expression of IDPc or IDPm, NIH3T3 cells were stably transfected with mouse IDPc or IDPm cDNA in either the sense or the antisense direction. The transfected cells with either increased or decreased IDPc or IDPm were exposed to gamma-rays, and the levels of reactive oxygen species generation, protein oxidation and lipid peroxidation were measured.

RESULTS

Both IDPc and IDPm activities were induced by gamma-ray in NIH3T3 cells. Cells with decreased expression of IDPc or IDPm had elevated reactive oxygen species generation, lipid peroxidation and protein oxidation. Conversely, overproduction of IDPc or IDPm protein partially protected the cells from oxidative damage induced by gamma-ray irradiation.

CONCLUSIONS

The protective role of IDPc and IDPm against gamma-ray-induced cellular damage can be attributed to elevated NADPH, reducing equivalents needed for recycling reduced glutathione in the cytosol and mitochondria. Thus, a primary biological function of the ICDHs may be production of NADPH, which is a prerequisite for some cellular defence systems against oxidative damage.

Haemocompatibility of polymer-coated stainless steel stents as compared to uncoated stents

Acute and subacute stent thrombosis still represent an unsolved problem in connection with endovascular stents. For this reason coatings are tested now with the intention to reduce thrombogenicity of stainless steel surfaces. This comparative study examined whether a polymeric stent coating affected the haemocompatibility of a stainless steel stent. For compatibility testing, coated and non-coated stents were implanted in a low-grade thrombogenic closed-loop system perfused with platelet rich plasma at shear rates far below the threshold value at which shear-rate-induced activation of thrombocytes occurs. After 21 circulations of the filling volume (exposure time: 6.2 min), the number of single circulating platelets in the perfusion system with uncoated stainless steel stents decreased almost twice as much as was the case with polymer-coated stents. This is thought to indicate that more thrombocytes had adhered to the uncoated stainless steel stent, or that the thrombocytes were clustered in circulating aggregates. Parallel to the platelet aggregation/adherence, a release reaction took place, as was evident from the TAT complexes indicating the generation of thrombin. In the case of the implantation of uncoated stainless steel stents, both the number of activated circulating thrombocytes and the level of platelet reactivity (number of thrombocytes circulating in the plasma as aggregates) were notably higher than in the system with polymer-coated stents. At the same time it should be noted that the activation or aggregation is almost wholly attributable to the exogenic surface of the implanted stent, since activation due to the tube system or to shear rate can be excluded (as shown by measurements of the system without a stent). In addition to activation of the thrombocytes, a notable increase in the number of receptors per platelet (significant only in the system with the uncoated stent) took place. This supports both the adherence of the thrombocytes and their readiness to aggregate, since more receptors (docking places for ligands) are available. The better haemocompatibility of the polymer-coated stents, as verified in the laboratory, was also evident under microscopic examination of the explanted stents following the perfusion tests.

Effect of desmopressin (DDAVP) on platelet membrane glycoprotein expression in patients with von Willebrand's disease

When patients with von Willebrand's disease were given a single injection of desmopressin (0.4 microg/kg body weight), there was a considerable increase in platelet reactivity (from 0.95 +/- 0.19 to 1.44 +/- 0.42; p = 0.0033). On flow cytometry, increased glycoprotein Ib/IX expression in the platelets was found after the desmopressin injection; when phycoerythrin-marked anti-CD62 antibodies were used, the mean fluorescence rose from 428.9 +/- 56.6 to 440.7 +/- 51.4 (p = 0.0056), and from 425.9 +/- 55.0 to 437.4 +/- 53.9 (p = 0.0018) when phycoerythrin-marked anti-thrombospondin antibodies were used. Apart from the rise in the von Willebrand factor, this could explain the increased platelet reactivity. However, the surface expression of CD62, CD63 and thrombospondin on platelets did not change following the desmopressin injection.

Analysis of heat-processed corn foods for fumonisins and bound fumonisins

Thirty retail samples of heat-processed corn foods, i.e. corn flakes, corn-based breakfast cereals, tortilla chips and corn chips, were analysed for fumonisins--fumonisin B1 (FB1), fumonisin B2 (FB2) and hydrolysed FB1 (HFB1)--as well as for protein- and total-bound FB1. Bound (hidden) fumonisins cannot be detected by conventional analysis. Improved methods for the determination of bound FB1 were developed. The protein-bound FB1 was extracted with 1% sodium dodecylsulfate (SDS) solution. The SDS, which interfered with high-performance liquid chromatography (HPLC) analysis, was then separated from protein-bound FB1 by complexing with methylene blue followed by solvent extraction and hydrolysis with 2 N KOH. To measure total-bound FB1, the sample itself was hydrolysed with KOH. In both cases, clean-up was accomplished on an OASIS polymeric solid-phase extraction column and the bound fumonisins were determined by HPLC measurement of HFB1. Fourteen of 15 samples of corn flakes and other corn-based breakfast cereals analysed contained detectable levels of FB1 with a mean in positive samples of 67ng g(-1) (13-237 ng g(-1)). Two samples also had detectable levels of FB2 (21-23ng g(-1)). Bound FB1 was found in all samples; the mean protein-bound FB1 measured was 58 ng g(-1) (22-176 ng g(-1)) and the mean total-bound FB1 measured was 106 ng g(-1) (28-418 ng g(-1)), reported as FB1 equivalents after correction for recoveries of HFB1. There was an average of about 1.3 times more FB1 in the bound form compared with extractable FB1, and this was about twice as much as protein-bound FB1. Seven of the 15 samples of alkali-processed corn-based foods, such as tortilla chips and corn chips, contained FB1 and three contained HFB1 with means in measurable positive samples of 78 (48-134) and 29 (13-47) ng g(-1), respectively. Five of these alkali-processed corn foods contained bound FB1; the mean measurable protein-bound FB1 was 42 ng g(-1) (39-46 ng g(-1)) and the mean measurable total-bound FB1 was 100 ng g(-1) (54-209 ng g(-1)). HFB1 derived from bound FB1 in selected samples was confirmed by HPLC with mass spectrometry (MS).

Sequence variation in the gene encoding the major capsid protein of Korean fish iridoviruses

Ten iridoviruses were isolated from cultured fish from various regions in Korea; 7 from rock bream, 1 from red sea bream, 1 from sea bass, and 1 from rockfish. The full open-reading frame (ORF) encoding the major capsid protein (MCP) (1362 bp) from ten iridoviruses were sequenced and the nucleotide sequences were phylogenetically analyzed. Phylogenetic analysis revealed that the ten Korean isolates were classified into one cluster. However, their sequences were not identical and, based on the nucleotide sequence variation, they could be further divided into two subgroups. While nine Korean isolates were similar to the Japanese isolate red sea bream iridovirus (RSIV), one isolate was distinct from other iridovirus isolates. These results suggest that a diversity of iridoviruses exist in Korea and that a new variant strain has emerged.

Computer-aided detection of kidney tumor on abdominal computed tomography scans

PURPOSE

To implement a computer-aided detection system for kidney segmentation and kidney tumor detection on abdominal computed tomography (CT) scans.

MATERIAL AND METHODS

Abdominal CT images were digitized with a film digitizer, and a gray-level threshold method was used to segment the kidney. Based on texture analysis performed on sample images of kidney tumors, a portion of the kidney tumor was selected as seed region for start point of the region-growing process. The average and standard deviations were used to detect the kidney tumor. Starting at the detected seed region, the region-growing method was used to segment the kidney tumor with intensity values used as an acceptance criterion for a homogeneous test. This test was performed to merge the neighboring region as kidney tumor boundary. These methods were applied on 156 transverse images of 12 cases of kidney tumors scanned using a G.E. Hispeed CT scanner and digitized with a Lumisys LS-40 film digitizer.

RESULTS

The computer-aided detection system resulted in a kidney tumor detection sensitivity of 85% and no false-positive findings.

CONCLUSION

This computer-aided detection scheme was useful for kidney tumor detection and gave the characteristics of detected kidney tumors.

Functional and genetic assessment of IFN-gamma receptor in patients with clinical tuberculosis

OBJECTIVE

The molecular basis of the genetic vulnerability underlying the most common form of clinical tuberculosis (TB) remains largely unknown. We speculated that mild genetic defects in the interferon-gamma (IFN-gamma) signalling pathway caused a subtle functional impairment of IFN-gamma which would explain susceptibility to Mycobacterium tuberculosis in clinical TB.

DESIGN

A case-control study.

RESULTS

We evaluated functional responsiveness to IFN-gamma in monocytes from patients with clinical TB (n = 10), and analysed the genetic sequences of the IFN-gamma receptor 1 (IFN-gammaR1) and STAT1 genes in patients with disseminated TB (n = 18). IFN-gamma stimulated an increase in the expression of HLA-DR and CD64 on monocytes of both controls and patients; the rate of increase in expression was the same in both groups. Treatment with IFN-gamma before lipopolysaccharide (LPS) stimulation further increased tumour necrosis factor-alpha (TNF-alpha) production as compared to TNF-alpha production with LPS stimulation alone; the rate of increase in TNF-alpha production was the same in both groups. The known mutations in the coding sequences of the IFN-gammaR1 and STAT1 genes were not found in the patients with disseminated tuberculosis.

CONCLUSION

These results suggest that impairment of the IFN-gamma signalling pathway did not account for cases of clinical TB in this study.

Robust Motor Speed Control under Time Varying Loads in Moving Actuator Type artificial Heart (AnyHeart)

The Moving Actuator type artificial heart(AnyHeart) as well as many other artificial hearts uses a motor as its power source. For controllability of control parameters such as pump rate, pump output, blood pressure profile and flow form, the precise motor speed control is important. However, because the implantable device has limited carrying capacity of hardware components in size and number, applying diverse motor control methods are not possible. In addition, the existing PI (Proportional-Integral) motor controller does not show satisfactory performance.

A new controller that is sufficiently robust for the changes of load and physical system parameters has been designed and tested. The robust speed controller is based on the sliding mode control method that is applicable to a system of which the ranges of uncertainty in physical parameters are known.

In a mock circulation system test, the actual speed showed good tracking characteristics in respect to the reference speed. Fast follow-up characteristics were also observed under high afterload and speed conditions. The speed error, current and power consumption were reduced by about 40%. The proposed control technique overcomes the limitations of the PI controller, and makes important improvements in both performance and stability.

Estimation of the daily exposure of Koreans to aflatoxin B1 through food consumption

A survey for aflatoxin B(1) (AFB(1)) was conducted on 88 food-grade rice samples randomly collected during July and August 2002 in Seoul, Korea. The presence of AFB(1) was determined by enzyme-linked immunosorbent assay, and the positive samples from enzyme-linked immunosorbent assay were confirmed using high-performance liquid chromatography. Besides this, from the surveying data from the literature published since 1997, the intake of AFB(1) from food in Korea was calculated and compared with the provisional maximum tolerable daily intakes. Naturally occurring AFB(1) was found in 5/88 (6%) samples of rice with an average of 4.8 ng g(-1). A calculated probable daily intake of AFB(1) for Koreans fell into the range 1.19-5.79 ng kg(-1) bw day(-1), hence exceeding the estimated provisional maximum tolerable daily intakes. In conclusion, the exposure of Koreans to AFB(1) could bring about health concerns. This is the first report discovering that rice is the major contributor to the dietary intake of AFB(1) in Korea.

Qualitative und quantitative Beschreibung von myokardialen Ischämien mittels Magnetokardiographie / Qualitative and Quantitative Description of Myocardial Ischemia by means of Magnetocardiography

In the framework of this study quantitative parameters are presented which, derived from magnetocardiographic maps, aid in making a conclusion about ischemia in the myocardium. The analysis is based on the examination of 86 patients with unstable angina, of which 53 exhibited myocardial ischemia with high probability (Group I: angiographically proven stenosis of at least 50% in a coronary artery of first or second order and positive troponin), while in the 33 other patients myocardial ischemia could be ruled out with high probability (Group II: angiographically clean coronary bed and normal troponin values). The negative predictive value (the probability that there is no myocardial ischemia when the magnetocardiogram (MCG) is negative) is 96.2%; the positive predictive value (the probability that there is actually coronary heart disease when the magnetocardiogram is positive) is 91.2%. A 12-lead ECG taken at the same time as the MCG achieved a positive predictive value of 92.8%, but a negative predictive value of 53.4%. Consequently, the boundary values of the parameters selected lead to a markedly distinct separation between patients with myocardial ischemia from those without. For ruling out coronary heart disease in patients with unstable angina the MCG is superior to 12-lead ECG.

Sildenafil improves cutaneous microcirculation in patients with coronary artery disease: a monocentric, prospective, double-blind, placebo-controlled, randomized cross-over study

Endothelial dysfunction of precapillary arterioles impairs nutritional microcirculation at rest as well as during post-ischemic reactive hyperemia. In this monocentric, prospective, double-blind, placebo-controlled, randomized cross-over study we investigated the acute effect of 50 mg sildenafil, a selective PDE-5 inhibitor, on resting and post-ischemic capillary circulation in twenty patients with angiographically confirmed coronary artery disease not taking nitrates or NO-donors. Mean erythrocyte velocity in digital nail-fold capillaries was determined before and after sildenafil and placebo, both baseline and after a three-minutes supra-systolic occlusion of the upper arm. Primary efficacy parameter was the drug effect on peak velocity during reactive hyperemia (peak velocity: V(max)). Post ischemic maximal capillary erythrocyte velocity V(max) significantly increased by 47% one hour after 50 mg sildenafil (mean value+/-standard deviation: 0.85+/-0.42 mm/s vs. 0.58+/-0.18 mm/s at baseline, p=0.0023), whereas placebo had no effect (p=0.5248). The difference between sildenafil and placebo was significant (p=0.0129) and sildenafil's effect can be regarded as biometrically highly relevant with standardized difference according to Cohen of 0.81. In spite a small decrease of both systolic and diastolic blood pressure after sildenafil, sildenafil significantly increased capillary erythrocyte velocity at rest.

CONCLUSION

A single oral dose of sildenafil significantly increased resting and post-ischemic cutaneous capillary circulation in patients with coronary artery disease. Future studies should assess whether sildenafil also improves nutritional capillary blood flow in other organs and in other diseases with impaired endothelial function and microcirculation, for example in diabetic microangiopathy.

Effect of LDL apheresis on oxygen tension in skeletal muscle in patients with cardiac allograft vasculopathy and severe lipid disorder

In this study, the extent to which intramuscular pO2 is influenced by a single HELP-apheresis (Heparin-induced Extracorporeal LDL Precipitation) was investigated in 10 patients with cardiac allograft vasculopathy (CAV) and severe lipid disorder. For this purpose, a sterile flexible pO2 microcatheter was inserted into the anterior tibial muscle and pO2 monitoring was begun 10 minutes before starting apheresis treatment. The intramuscular pO2 values were recorded continuously until the end of apheresis treatment and a subsequent 30-minute further observation phase. The patients with CAV and severe lipid disorder presented with 11.6+/-3.8 mmHg significantly and pathologically reduced intramuscular pO2 (p<0.001). LDL apheresis resulted in a significant increase in pO2 in the anterior tibial muscle. Thirty minutes after the end of HELP-apheresis, intramuscular partial oxygen pressure had increased by 162% and showed values at this point, 30.3+/-9.8 mmHg, similar to those found in healthy subjects.

Estimation of coupled assist flows in a moving-actuator bi-ventricular assist device using interventricular pressure

An assist flow estimation scheme for a moving-actuator biventricular assist device (MA-BVAD) using interventricular pressure (IVP) has been developed. The scheme uses a waveform feature parameter of IVP, peak IVP time (PIT), for estimation of the filling volumes of both left and right blood sacs simultaneously. In a regression analysis on data from an in vivo test in an 85 Kg male calf for 20 days, the PIT was found to have high correlation with the blood sac filling volume (R=0.883: left filling volume, R=0.967: right filling volume). A conceptual equation hypothesizing this correlation between PIT and filling volume was established based on the observation and the unknown parameters were identified using least squares parameter optimization. The estimation equation identified proved highly accurate (R=0.916 for left flow, R=0.970 for right flow). The accuracy of the estimation scheme promises very good practical applicability.

Microscopic origin of surface-plasmon radiation in plasmonic band-gap nanostructures

We report spatial domain measurements of the damping of surface-plasmon excitations in metal films with periodic nanohole arrays. The measurements reveal a short coherent propagation length of a few microm inside nanohole arrays, consistent with delays of about 10 fs in ultrafast transmission experiments. This implies that the transmission spectra of the entire plasmonic band-gap structure are homogeneously broadened by radiative damping of surface-plasmon excitations. We show that a Rayleigh-like scattering of surface plasmons by the periodic hole array is the microscopic origin of this damping, allowing the reradiation rate to be controlled.

AnyHeart: a single-piece heart-saving implantable artificial heart (BVAD)--monitoring and estimation

AnyHeart is a single-piece, implantable biventricular assist device. This electromechanical BVAD has a moving-actuator mechanism. To monitor the status of AnyHeart from anywhere at any time, a portable personal digital assistant (PDA) monitor and web-based remote monitoring system were developed. The PDA local monitoring system has replaced bulky personal computer monitoring systems. The web-based remote monitoring system has several functions such as data collecting, storing, and posting through the internet. Basically, interventricular pressure (IVP) is a parameter indicating the filling level of the blood chambers of AnyHeart. The pump output can be estimated using IVP, which is acquired noninvasively from AnyHeart. With the proposed method, we can estimate the pump output with a small margin of error.

Natural co-occurrence of aflatoxin B1, fumonisin B1 and ochratoxin A in barley and corn foods from Korea

A survey for aflatoxin B1 (AFB1), fumonisin B1 and ochratoxin A (OTA) was conducted on 127 samples that included 30 food-grade barley, 32 barley foods, 18 food-grade corn and 47 corn foods, randomly collected during 1998-99 in Seoul, Korea. The presence of mycotoxins was analysed by direct competitive enzyme-linked immunosorbent assay (ELISA), and most of the positive samples from ELISA were confirmed using high-performance liquid chromatography (HPLC). Recoveries of AFB1 and OTA spiked at 10 ng g(-1) and FB1 spiked at 50 ng g(-1) were 106, 87 and 105% by ELISA, whereas those by HPLC were 80, 79 and 84%, respectively. Detection limits by ELISA for AFB1, FB1 and OTA were 1, 5 and 5 ng g(-1), and those by HPLC were 0.6, 35 and 1 ng g(-1). Naturally occurring AFB1, FB1 and OTA were found in 4/32 (12%), 2/32(6%) and 4/32 (12%) samples of barley foods with an average of 26, 16 and 9 ng g(-1), respectively. AFB1 and FB1 in corn foods were detected in 4/47 (8%) and 9/47 (19%) samples with the average being 20 and 74 ng g(-1), while no OTA was found in any corn foods samples. No AFB1, FB1 or OTA was detected in any of food-grade barley and corn samples. This is the first report on the natural co-occurrence of AFB1 and FB1 in barley and corn foods as well as on surveillance of OTA in Korea.

Pharmacokinetics of pravastatin in heart-transplant patients taking cyclosporin A

BACKGROUND

Heart transplantation is an established tool for the treatment of terminal heart failure. Hyperlipidemia is a common problem following heart transplantation and has been implicated as an additional risk factor in the development of transplant coronary artery disease (TxCAD). Therefore, heart recipients are commonly treated with inhibitors of cholesterol synthesis (HMG-CoA reductase inhibitors). However, these patients have an increased risk of developing rhabdomyolysis due to elevated concentrations of HMG-CoA reductase inhibitors under co-administration with the immunosuppressive cyclosporin A (CsA).

AIM OF THE STUDY

Aim of our study was to obtain pharmacokinetic data on pravastatin whilst monitoring the safety and efficiency of the lipid lowering therapy in heart-transplant recipients under immunosuppression with CsA and to compare these data to those of a healthy control group.

SUBJECTS, MATERIALS AND METHODS

Eleven patients (30.2 +/- 12.3 months after transplantation) receiving immunosuppressive therapy consisting of cyclosporin A, prednisone and azathioprine with LDL cholesterol (LDL-C) concentrations exceeding 3.9 mmol/l and 8 control subjects were included into the study. In addition to the immunosuppressive therapy, the patients received a daily dose of 40 mg/day pravastatin for the first 8 days which was then reduced to 10 mg/day administered until Day 29. Blood was sampled for pharmacokinetic profiling (maximum concentration of the drug (Cmax), time to reach Cmax (tmax), area under the concentration vs. time curve (AUC(0-24h)), elimination half-life time (tcl)) and measurement of the parameters of clinical chemistry on Days 1, 8 and 29. The control group received a single dose of 60 mg pravastatin and the values of Cmax and AUC(0-24h) were normalized for a dose of 10 mg.

RESULTS

Pravastatin 40 mg/day for 1 week in the patient group caused a significant reduction in total cholesterol (C) and LDL-C from 8.11 +/- 1.20 mmol/l and 5.88 +/- 1.15 mmol/l to 6.91 +/- 1.01 mmol/l and 4.72 +/- 1.05 mmol/l, respectively (p = 0.005 and p = 0.003). Triglycerides and HDL cholesterol (HDL-C) concentrations did not change significantly. Mean values for Cmax of pravastatin were 384.2 ng/ml, 392.0 ng/ml and 115.1 ng/ml in patients on Days 1, 8 and 29, respectively. After normalization for a dose of 10 mg, the corresponding values of C(max-DN10mg) and Cmax were 96.0 ng/ml, 98.0 ng/ml and 115.1 ng/ml on study Days 1, 8 and 29. These values were 7-8 times higher than the normalized value of C(max-DN10mg) for the control group (13.7 ng/ml). The corresponding values of AUC(0-24h) were 1228.2 ng/ml x h, 1214.1 ng/ml x h and 345.9 ng/ml x h in the patient group on study Days 1, 8 and 29 as well as 157.5 ng/ml x h in the control group prior to normalization. After normalization for a dose of 10 mg, the values of AUC(0-24h-DN10mg) in the patient group were approximately 12 times higher than those of the control group. However, no significant differences between the 2 groups were observed in tmax and tcl. Within the patient group, no significant increase in Cmax or AUC was found on Day 1 to Day 8. The results of creatine kinase (CK), lactate dehydrogenase (LDH), aspartate aminotransferase (ASAT) and alanine aminotransferase (ALAT) showed also no significant increase during the observation period.

CONCLUSION

Heart-transplant recipients treated with the HMG-CoA reductase inhibitor pravastatin generally show higher plasma concentrations of this drug than control subjects. However, our data suggest that the HMG-CoA reductase inhibitor pravastatin can be used effectively in these patients receiving the immunosuppressive cyclosporin A. The pharmacokinetic data obtained indicate that there is no significant cumulation of the drug following multiple dosages in spite of increased drug concentrations after a single oral dosage.

Der p 2 isoallergens have different allergenicity, and quantification with 2-site ELISA using monoclonal antibodies is influenced by the isoallergens

BACKGROUND

Der p 2 isoallergens have been reported and the possibility of different allergenicity has also been suggested. In addition, the quantification with 2-site ELISA may be affected by the isoallergens.

OBJECTIVES

Two different recombinant Der p 2 (rDer p 2) isoallergens were compared in terms of human IgE responses and the reliability of quantification of them with two-site ELISA kits which use monoclonal antibodies (mAbs) as capture and detection of Der p 2.

METHODS

Seven different Der p 2 cDNA from the cultured Dermatophagoides pteronyssinus (DP) were cloned and polymorphism in nine amino acid residues was found. Two different recombinant isoallergens (rDer p 2A and rDer p 2B) were expressed and compared to their human IgE immune responses by ELISA and the ELISA inhibition test with 23 sera of DP-allergic patients. The reliability of quantification of two different available 2-site ELISA kits, which used mAbs for capture and detection of Der p 2, was evaluated.

RESULTS

The ELISA optical density of rDer p 2B-specific IgE (sIgE) was higher than that of rDer p 2A (P < 0.001). The ELISA inhibition curve of rDer p 2B sIgE in pool I sera (n = 5; high sIgE both to rDer p 2A and rDer p 2B) did not show any differences in the 50% inhibition concentration and maximum inhibitory percentage of rDer p 2A and rDer p 2B sIgE. However, with pool II sera (n = 5; markedly higher sIgE to rDer p 2B than rDer p 2A), the 50% inhibitory concentrations (10 microg/mL vs. 40 ng/mL) and maximum inhibitory percentage (61% vs. 99%) of rDer p 2B sIgE with the two recombinant isoallergens were quite different. rDer p 2B could be quantified with two different 2-site ELISA kits, but rDer p 2A was detected by only one kit.

CONCLUSION

We conclude that isoallergens of Der p 2 may have different IgE immune responses. Quantification of Der p 2 with 2-site ELISA kits that adopted mAbs, might be affected by the prevalent form of the isoallergens in reservoir dust.

Occurrence of zearalenone in Korean barley and corn foods

The presence of zearalenone (ZEN) in Korean foods such as barley, barley-based foods, corn, corn-based foods, fruits and vegetables was investigated by direct competitive enzyme-linked immunosorbent assay (dcELISA) and the liquid chromatography (LC) method. A total of 164 samples was collected from Seoul, Korea, in 1998 and 1999 including 30 barley, 32 barley-based foods, 18 corn, 47 corn-based foods, 19 dried red pepper, nine dried jujube, and nine dried persimmon. Average recoveries of ZEN from barley and corn by dcELISA were 138 and 145%, and by LC were 91 and 83% respectively at spiking levels of 5-500 ngg(-1). The detection limit for ZEN was 3 ng g(-1) by dcELISA and 4 ngg(-1) by LC. From 164 samples analysed, ZEN was found by dcELISA in 35 samples (21%) with a mean level of 30 ng g(-1). Barley-based foods had the highest incidence of ZEN (38%) followed by barley (33%), corn-based foods (26%) and corn (22%). No ZEN was detected in any red pepper, jujube or persimmon samples. A high degree of correlation (r2 = 0.86) was observed between the 35 positive samples detected by dcELISA and 31 samples by LC.