Liquid Chromatographic Determination of Fumonisins B1, B2, and B3 in Corn: AOAC–IUPAC Collaborative Study

A liquid chromatographic (LC) method for simultaneous determination of fumonisins B1 (FB1), B2 (FB2), and B3 (FB3) in corn was subjected to a collaborative study involving 12 participants from 10 countries, in which the accuracy and reproducibility characteristics of the method were established. Mean analyte recoveries from corn ranged from 81.1 to 84.2% for FB1 (at a spiking range of 500 to 8000 ng/g), from 75.9 to 81.9% for FB2 (at a spiking range of 200 to 3200 ng/g), and from 75.8 to 86.8% for FB3 (at a spiking range of 100 to 1600 ng/g). The valid data were statistically evaluated after exclusion of outliers. Relative standard deviations for within-laboratory repeatability ranged from 5.8 to 13.2% for FB1, from 7.2 to 17.5% for FB2, and from 8.0 to 17.2% for FB3. Relative standard deviations for between-laboratory reproducibility varied from 13.9 to 22.2% for FB1, from 15.8 to 26.7% for FB2, and from 19.5 to 24.9% for FB3. HORRAT ratios, calculated for the individual toxin analogues, ranged from 0.75 to 1.73. The LC method for determination of fumonisins B1, B2, and B3 in corn (at concentrations of 800–12800 ng total fumonisins/g) has been adopted by AOAC INTERNATIONAL.

One Health collaborations for zoonotic disease control in Ethiopia

Zoonotic diseases require a One Health approach for successful control and elimination due to the nature of their transmission between animals and humans. One Health recognises that the health of humans, animals, and the environment are all interconnected. Ethiopia has committed itself to controlling five prioritised zoonotic diseases (rabies, anthrax, brucellosis, leptospirosis and echinococcosis), using a One Health approach. The National One Health Steering Committee (NOHSC) provides a framework for national stakeholders to address gaps in multisectoral communication, coordination and collaboration. In addition, the NOHSC oversees the formation of several specialised disease-focused groups, referred to as 'Technical Working Groups' (TWGs). These TWGs are responsible for developing disease prevention and control strategies, as well as implementing disease-focused public health activities and providing recommendations to the NOHSC. Ethiopia's success using the One Health approach and its efficient control of zoonotic diseases will depend on the commitment of all member Ministries to support the NOHSC and TWGs, as well as to build capacity in Ethiopia's workforce and laboratories, a task supported by its many international partners.

Radionuclide Assessment of the Natural Heart Ejection Fraction before and after LVAD Implantation

Complete pressure unloading of the ventricles can preserve ischemically damaged myocardium. Most clinical left heart assist device (LVAD) systems used after ischemic injury of the heart apply atrial cannulation which does not ensure pressure unloading. In order to assess the effect of the implantation of an intracorporeal LVAD on the function of the natural heart, we determined the ejection fraction (EF) in four male Holstein calves (90–105 kg) before and after insertion of a Cleveland Clinic pneumatic LVAD. A gated blood pool scan was obtained with a gamma camera after injection of 40 mCi Tc-labelled albumin. The animals were restrained in a sling to avoid movement artifacts.

All animals showed a drop of 65 ± 12% to 42 ± 14% EF in the first postoperative (p.o.) week. Left ventricular output did not maintain sufficient blood pressure as assessed by pump-off tests. Systolic blood pressure dropped from 122 ±6.5 mm Hg to 81 ± 6 mm Hg without pump support on the morning of the first p.o. day.

Apical coring and possible restrained heart movement by the implanted LVAD may lead to impaired myocardial function that renders the individual LVAD dependent until adaptative corrections take place.

Implications of new legislation (US FSMA) and guidelines (EC) on the establishment of management systems for agricultural water

This report summarizes key messages related to agricultural water quality as discussed by an ad hoc panel at the 1st International Symposium of Food Safety in Santiago, Chile. Participating representatives of the academia, industry and government of diverse geographical backgrounds and the audience discussed topics such as (1) implications of the US Food Safety Modernization Act (FSMA: www.fda.gov/Food/GuidanceRegulation/FSMA/ucm277706.htm) on the Agricultural Water Quality, (2) comparisons between MPN and CFU in analyzing water quality, (3) alternatives to fecal indicator bacteria (FIB) to be used as indicators to evaluate water quality, and (4) vegetative buffers as an alternative to reduce pathogen loads in agricultural surface waters. Panelists identified the following key messages for each topic discussed that are related to agricultural water quality: (1) the FSMA regulation and the new guidance document elaborated by the EC are highly relevant as they provide a definition of agricultural water and specific criteria for different water uses and circumstances; (2) FSMA supports modification from MPN to CFU; (3) Growers require more alternatives for treatment of agricultural water; (4) Vegetative buffers are a potential practical and feasible alternative for agriculture producers to reduce the pathogen and fecal pollution loads of in their agricultural waters.

Comparison of human and southern sea otter (Enhydra lutris nereis) health risks for infection with protozoa in nearshore waters

Cryptosporidium and Giardia spp. are waterborne, fecally-transmitted pathogens that cause economic loss due to gastroenteritis and beach closures. We applied quantitative microbial risk assessment (QMRA) to determine the health risks for humans and sea otters due to waterborne exposure of Cryptosporidium and Giardia spp. when swimming in three types of surface waters: river, stormwater and wastewater effluent during the wet and dry seasons in the central coast of California. This is the first application of QMRA to estimate both the probability of infection in Southern sea otters and the probability of illness in humans, using microbial source tracking (MST) as a variable. Children swimming close to stormwater discharges had an estimated Cryptosporidium-associated illness probability that exceeded the accepted U.S. EPA criteria (32 illnesses/1000 swimmers or 3.2%). Based on the assumption that sea otters are as susceptible as humans to Cryptosporidium infection, the infection probabilities were close to 2% and 16% when sea otters were swimming at the end of points of rivers and stormwater discharges, respectively. In the case of Giardia, infection probabilities of 11% and 23% were estimated for sea otters swimming at the end of point of wastewater discharges, assuming that sea otters are as susceptible as gerbils and humans, respectively. The results of this QMRA suggest that 1) humans and sea otters are at risk when swimming at outflow sites for rivers, stormwater and treated wastewater effluent; 2) reduced loads of viable protozoan cysts and oocysts in recreational water can lessen the probability of infection of humans and sea otters; and 3) the risk of infection of humans and sea otters can be reduced with the treatment of wastewater to decrease oocyst and cyst viability before effluent is released into the sea.

A preliminary evaluation into the performance of posterior resin bonded cast metal restorations (adhesive onlays)

Posterior resin bonded cast metal restorations (adhesive onlays) were used in a variety of clinical scenarios including: management of tooth wear and cracked tooth, as retainers for fixed bridge work, for correction of the occlusal plane and in providing cuspal coverage following endodontic treatment. The mean length in service for the examined onlays was 42 months, with a range of 9-75 months. Two restorations in two patients failed resulting in an overall success of 94%. Patient satisfaction was high at 95%. Such restorations seem to be a viable option for managing a number of clinical scenarios.

Surface properties of dental nanocomposites after finishing with rigid rotary instruments

This study evaluated the surface characteristics of three nanoparticle resin composites (Z350, Heritage 7 Nanohybrid, and Ice) using profilometry and scanning electronic microscopy (SEM) after subjecting them to sequential finishing procedures using rigid rotary instruments. Fifteen 8 mm × 8 mm × 2 mm specimens were fabricated for each tested composite and subjected to one of the following finishing regimens: finishing with green stones followed by white stones, finishing with 45-μm diamond followed by 15-μm diamond, finishing with a 12-fluted carbide followed by a 20-fluted carbide. After finishing, the surfaces were subjected to profilometric testing. Eight parallel tracings were used to scan the finished surface of each specimen. For each recorded profile, the average roughness (Ra) and extreme value descriptor (Rmax) were recorded. On completion of the profilometric testing, two specimens from each group were randomly selected for qualitative assessment by SEM. Profilometric data was analyzed using a one-way analysis of variance and post hoc Scheffe tests. The results demonstrated that the three control groups of the tested nanocomposites behaved as a coherent group with respect to surface roughness. With the exception of the nanohybrid Heritage 7 finished with the carbide instruments, all composites showed an increase in surface roughness. The Z350 and Ice finished with the carbide finishing instruments showed no statistically significant increase in Ra, but both of these composites showed significantly rougher surfaces when finished with diamonds compared with controls. The nanohybrids Ice and Heritage 7 demonstrated significantly higher roughness in terms of Rmax when finished with stones. The SEM correlated well with roughness measurements. The conclusion may be drawn that diamonds and stones produce unacceptable surfaces in terms of roughness on the tested nanocomposites whereas finishing carbides produce acceptable surfaces.

Effect of Reduced Exposure Times on the Microhardness of Nanocomposites Polymerized by QTH and Second-generation LED Curing Lights

Reduced polymerization times suggested with newer generation LED-curing lights may not be suitable to ensure sufficient conversion of all types of nanocomposites at depths of 2 mm.

Structural and IgE binding analyses of recombinant Der p 2 expressed from the hosts Escherichia coli and Pichia pastoris

BACKGROUND

The house dust mite allergen Der p 2 is one of the most important indoor allergens associated with allergic disease. Recombinant Der (rDer) p 2 with high IgE binding activity can be readily produced in Escherichia coli and Pichia pastoris, but the structure and IgE binding of the different methods of preparation have not been compared.

METHODS

Secondary structure was assessed by circular dichroism (CD). Intrinsic fluorescence and hydrophobic probe (1-anilinonaphthalene 8-sulphonic acid, ANS) were used to study the Der p 2 hydrophobic cavity. IgE binding was assessed by ELISA inhibition.

RESULTS

CD analysis showed the expected secondary structure for both nDer p 2 and refolded Der p 2 prepared from E. coli inclusion bodies but primarily random structure for Der p 2 secreted from P. pastoris. The secreted product, however, had disulphide bonding and could be refolded to a similar structure to natural Der (nDer) p 2 after precipitation with trichloro-acetic or ammonium sulphate. ANS binding and intrinsic Trp92 fluorescence showed that all recombinant proteins were different to nDer p 2 and that the allergen secreted from P. pastoris did not form a hydrophobic cavity. Despite the marked structural changes, all preparations of Der p 2 had similar IgE binding to nDer p 2.

CONCLUSION

Despite almost identical IgE binding, rDer p 2 prepared from both E. coli and P. pastoris showed structural differences to nDer p 2. Der p 2 secreted from P. pastoris lacked most of the natural structure, but refolding could induce the natural structure.

Transcranial magnetic stimulation in ALS: utility of central motor conduction tests

OBJECTIVE

To investigate transcranial magnetic stimulation (TMS) measures as clinical correlates and longitudinal markers of amyotrophic lateral sclerosis (ALS).

METHODS

We prospectively studied 60 patients with ALS subtypes (sporadic ALS, familial ALS, progressive muscular atrophy, and primary lateral sclerosis) using single pulse TMS, recording from abductor digiti minimi (ADM) and tibialis anterior (TA) muscles. We evaluated three measures: 1) TMS motor response threshold to the ADM, 2) central motor conduction time (CMCT), and 3) motor evoked potential amplitude (correcting for peripheral changes). Patients were evaluated at baseline, compared with controls, and followed every 3 months for up to six visits. Changes were analyzed using generalized estimation equations to test linear trends with time.

RESULTS

TMS threshold, CMCT, and TMS amplitude correlated (p < 0.05) with clinical upper motor neuron (UMN) signs at baseline and were different (p < 0.05) from normal controls in at least one response. Seventy-eight percent of patients with UMN (41/52) and 50% (4/8) of patients without clinical UMN signs had prolonged CMCT. All three measures revealed significant deterioration over time: TMS amplitude showed the greatest change, decreasing 8% per month; threshold increased 1.8% per month; and CMCT increased by 0.9% per month.

CONCLUSIONS

Transcranial magnetic stimulation (TMS) findings, particularly TMS amplitude, can objectively discriminate corticospinal tract involvement in amyotrophic lateral sclerosis (ALS) from controls and assess the progression of ALS. While central motor conduction time and response threshold worsen by less than 2% per month, TMS amplitude decrease averages 8% per month, and may be a useful objective marker of disease progression.

Facilitating and understanding the family's choice of injection device for growth hormone therapy by using conjoint analysis

BACKGROUND

Conjoint analysis involves the measurement of consumer preferences between choice alternatives.

AIMS AND OBJECTIVES

To investigate the use of conjoint analysis in facilitating and understanding choice of growth hormone injection devices.

METHOD AND SUBJECTS

56 patients and their parents participated in an electronic, computer-based interview. The interview took a median time of 18 min (range 12-30) and allowed an immediate matching of injection devices to the family's preferences.

RESULTS

Amongst the key drivers of choice, lack of bruising was rated highest and designated an index of 100. Compared to this, the remaining attributes in order of desirability were: auto-injector (98), lack of pain (93), lightweight (88), silent (82), ready-mixed (77), ease of holding (69), telephone helpline (66), needle-free (62), small size (60), nurse support (47), hidden needle (45), stored in fridge (13) and home delivery (6). Out of the 17 families who had already chosen a device previously by discussion with the clinic nurse, the computer model placed their device either as first or second out of seven devices tested.

CONCLUSION

Adaptive or interactive conjoint analysis applied at the patient level can facilitate the choice-making process whilst providing an insight into the relative importance of the key features that influence choice.

Studies of self-incompatibility in wild tomatoes: I. S-allele diversity in Solanum chilense (Dun.) Reiche [corrected] (Solanaceae)

We characterized the molecular allelic variation of RNases at the self-incompatibility (SI) locus of Solanum chilense Dun. We recovered 30 S-RNase allele sequences from 34 plants representing a broad geographic sample. This yielded a species-wide estimate of 35 (95% likelihood interval 31-40) S-alleles. We performed crosses to confirm the association with SI function of 10 of the putative S-RNase allele sequences. Results in all cases were consistent with the expectation that these sequences represent functional alleles under single-locus gametophytic SI. We used the allele sequences to conduct an analysis of selection, as measured by the excess of nonsynonymous changes per site, and found evidence for adaptive changes both within the traditionally defined hypervariable regions and downstream, near the 3'-end of the molecule.

Social marketing: an overview of approach and effects

This paper reviews the applicability of commercial and social marketing to teen driving safety. It draws on a wide range of information, including evaluation studies of specific programs as well as standards of practice within these two professions. Social marketing has been widely applied for more than three decades in the fields of public health, environmental protection, and political marketing with significant success. The paper attempts to distinguish between the practice of commercial marketing, whose goal is profit, and the practice of social marketing, whose goal is societal benefit. Issues of sustainability, segmentation, differences in behavioral characteristics, and cultural competence are discussed with specific examples drawn from the transportation safety literature. The paper suggests that social marketing represents a viable companion to control and education approaches to behavior change to promote teen driving safety.

Collected nondimensional performance of rotary dynamic blood pumps

"Nonpulsatile" or "continuous flow" blood pumps are a relatively new application of the rotary dynamic blood pumping principle. They fall outside the normal envelop of pumps, considering their small size, viscosity of the fluid pumped, need for particularly good internal flow patterns, and desire for high efficiency. This article establishes the state of the art in the field of blood pump performance. Trends in efficiency, shut off pressure coefficient, and nondimensional power behavior as a function of nondimensional flow are identified. Blood pumps show agreement with the published effects of low Reynolds numbers in conventional pumps.

Short exposure time sensitivity of white cells to shear stress

White cells are a critical functional element circulating in blood. This study sheared fresh whole bovine blood in stainless steel and polymeric capillary tubes of various lengths and diameters. Flow rate was constant, resulting in a range of exposure times and shear stresses. White cell count, cell integrity (trypan blue exclusion), and phagocytic index (latex bead ingestion) were assayed. It was found that cell function declined at lower stresses than cell count. White cell count was maintained at higher stress levels at the short exposure times used here compared with the published results at longer times. This study suggests that function, not count, is the critical parameter when studying shear effects on white cells, and that, like red cells, there may be an exposure time effect and that white cell function is impacted at stresses lower than are required for hemolysis.

Dissimilatory reduction of Cr(VI), Fe(III), and U(VI) by Cellulomonas isolates

The reduction of Cr(VI), Fe(III), and U(VI) was studied using three recently isolated environmental Cellulomonas sp. (WS01, WS18, and ES5) and a known Cellulomonas strain ( Cellulomonas flavigena ATCC 482) under anaerobic, non-growth conditions. In all cases, these cultures were observed to reduce Cr(VI), Fe(III), and U(VI). In 100 h, with lactate as electron donor, the Cellulomonas isolates (500 mg/l total cell protein) reduced nitrilotriacetic acid chelated Fe(III) [Fe(III)-NTA] from 5 mM to less than 2.2 mM, Cr(VI) from 0.2 mM to less than 0.001 mM, and U(VI) from 0.2 mM to less than 0.12 mM. All Cellulomonas isolates also reduced Cr(VI), Fe(III), and U(VI) in the absence of lactate, while no metal reduction was observed in either the cell-free or heat-killed cell controls. This is the first report of Cellulomonas sp. reducing Fe(III) and U(VI). Further, this is the first report of Cellulomonas spp. coupling the oxidation of lactate, or other unknown electron donors in the absence of lactate, to the reduction of Cr(VI), Fe(III), and U(VI).

Stability of the fusarium mycotoxins nivalenol, deoxynivalenol and zearalenone in ground maize under typical cooking environments

The effects of moisture, pH and heat on the stability of nivalenol (NIV), deoxtnivalenol (DON) and zearalenone (ZEN) present as natural contaminants of ground maize were measured for different periods. Standard solution tests were also performed to measure pH, salt and temperature effects on NIV and DON. The solution tests showed NIV and DON to be relatively stable in buffer solutions over the pH range 1-10. Quite harsh conditions (pH 12, high salt concentration, 80 degrees C, prolonged exposure) were needed to give substantial breakdown. In the ground maize substrate, these toxins were further stabilized relative to the solution tests. NIV and DON were both reduced (range 60-100%) by treatment with aqueous bicarbonate solution at 10, 20 or 50% of the ground maize dry weight, and subsequent heating at 80 or 110 degrees C for 2 and 12 days. There was no measurable reduction at lower test temperatures (20, 40 degrees C). NIV (but not DON) also showed some reduction following addition of water and heating at 80 or 110 degrees C for 12 days. ZEN content was not reduced even by 12 days of heating at 110 degrees C after treatment with a sodium bicarbonate solution.

Use of selective inhibitors and chromogenic substrates to differentiate bacteria based on toluene oxygenase activity

In whole-cell studies, two alkynes, 1-pentyne and phenylacetylene, were selective, irreversible inhibitors of monooxygenase enzymes in catabolic pathways that permit growth of bacteria on toluene. 1-Pentyne selectively inhibited growth of Burkholderia cepacia G4 (toluene 2-monooxygenase [T2MO] pathway) and B. pickettii PKO1 (toluene 3-monooxygenase [T3MO] pathway) on toluene, but did not inhibit growth of bacteria expressing other pathways. In further studies with strain G4, chromogenic transformation of alpha,alpha,alpha-Trifluoro-m-cresol (TFC) was irreversibly inhibited by 1-pentyne, but the presence of phenol prevented this inhibition. Transformation of catechol by G4 was unaffected by 1-pentyne. With respect to the various pathways and bacteria tested, phenylacetylene selectively inhibited growth of Pseudomonas mendocina KR1 (toluene 4-monooxygenase [T4MO] pathway) on toluene, but not on p-cresol. An Escherichia coli transformant expressing T4MO transformed indole or naphthalene in chromogenic reactions, but not after exposure to phenylacetylene. The naphthalene reaction remained diminished in phenylacetylene-treated cells relative to untreated cells after phenylacetylene was removed, indicating irreversible inhibition.These techniques were used to differentiate toluene-degrading isolates from an aquifer. Based on data generated with these indicators and inhibitors, along with results from Biolog analysis for sole carbon source oxidation, the groundwater isolates were assigned to eight separate groups, some of which apparently differ in their mode of toluene catabolism.

Effect of chemopreventive agents on DNA adduction induced by the potent mammary carcinogen dibenzo[a,l]pyrene in the human breast cells MCF-7

Over 1500 structurally diverse chemicals have been identified which have potential cancer chemopreventive properties. The efficacy and mechanisms of this growing list of chemoprotective agents may be studied using short-term bioassays that employ relevant end-points of the carcinogenic process. In this study, we have examined the effects of eight potential chemopreventive agents, N-acetylcysteine (NAC), benzylisocyanate (BIC), chlorophyllin, curcumin, 1,2-dithiole-3-thione (D3T), ellagic acid, genistein, and oltipraz, on DNA adduction of the potent mammary carcinogen dibenzo[a,l]pyrene (DBP) using the human breast cell line MCF-7. Bioactivation of DBP by MCF-7 cells resulted in the formation of one predominant (55%) dA-derived and several other dA- or dG-derived DNA adducts. Three test agents, oltipraz, D3T, and chlorophyllin substantially (>65%) inhibited DBP-DNA adduction at the highest dose tested (30 microM). These agents also significantly inhibited DBP adduct levels at a lower dose of 15 microM, while oltipraz was effective even at the lowest dose of 5 microM. Two other agents, genistein and ellagic acid were moderate (45%) DBP-DNA adduct inhibitors at the highest dose tested, while NAC, curcumin, and BIC were ineffective. These studies indicate that the MCF-7 cell line is an applicable model to study the efficacy of cancer chemopreventive agents in a human setting. Moreover, this model may also provide information regarding the effect of the test agents on carcinogen bioactivation and detoxification enzymes.

Allergens of wild house dust mites: environmental Der p 1 and Der p 2 sequence polymorphisms

BACKGROUND

Sequence diversity is a common feature of mite allergens. Previous studies, using predominantly commercial mite clones, have described several polymorphic residues for Der p 1 and Der p 2.

OBJECTIVE

This study aimed at determining the occurrence of sequence diversity in environmental mite isolates.

METHODS

Mites were isolated from houses in Perth and Sydney, Australia. Total RNA was extracted from 1 to 30 Perth mites, and cDNA was synthesized by reverse transcriptase PCR. Der p 1 and Der p 2 cDNAs were PCR amplified and sequenced. Genomic Der p 1 DNA was amplified from whole Sydney mites directly by PCR and then sequenced.

RESULTS

Twelve Der p 1 and 9 Der p 2 cDNA clones and 3 Der p 1 genomic DNA were analyzed and showed a high frequency of amino acid polymorphisms. Der p 2 displayed a clear pattern of divergence toward 2 alleles that differed by 4 amino acids and had characteristic silent nucleotide changes. The pattern for Der p 1 was different and unusual, with almost no silent nucleotide substitutions but frequent sporadic missense changes. Proliferative responses of peripheral blood mononuclear cells to peptides containing polymorphic residues of Der p 1 were detected in 8 of 19 subjects, with stimulation being found only for either one of the variant forms of the peptides. However, the responses to variants of whole recombinant allergens were similar, as shown for 4 variants of Der p 2.

CONCLUSION

Two clones for each of the allergens were identified as containing sequences that were largely representative of environmental isolates. A small-scale reverse transcriptase PCR used to produce cDNA from individual mites isolated from house dust will have wide application for studies on mite genetics and the production of recombinant mite allergens. Differences in T-cell responses to peptides representing variant epitopes were found, but responses to variants of whole recombinant allergens were similar. The GenBank and Swiss Prot database entries for Der p 1 (U11695) and Der p 2 (P49278) have been updated with the inclusion of the sequence polymorphisms described in this study.

The molecular basis of antigenic cross-reactivity between the group 2 mite allergens

BACKGROUND

Mite group 2 allergens Der p 2, Der f 2, and Eur m 2 are 14-kDa proteins of unknown function that share 83% to 85% amino acid sequence identity. Isoforms of the allergens within each genus have been identified which differ by 3 or 4 amino acids, but little is known of the influence of group 2 polymorphisms on human IgE antibody binding.

OBJECTIVE

The purpose of this study was to investigate the importance of interspecies and isoform substitutions on murine mAb and IgE antibody binding and on the molecular structure of the group 2 allergens.

METHODS

Site-directed mutagenesis was used to incorporate the isoform amino acid substitutions onto the Der p 2.0101 sequence. Recombinant allergens were expressed and purified from Escherichia coli and used to evaluate antibody binding by enzyme-linked immunosorbent assay (ELISA). Molecular modeling of the tertiary structure was used to analyze structural differences between the various group 2 allergens.

RESULTS

The substitution of asparagine for aspartic acid at position 114 restored mAb binding of rDer p 2.0101; the other Der p 2 isoforms and the 3 rDer f 2 isoforms also reacted in the 2-site ELISA. The correlation of IgE binding to the Der p 2 isoforms was excellent and tended to be higher in the isoforms with the asparagine 114 substitution (r (2) = 0.87 vs r (2) = 0.95). rEur m 2.0101 bound to all mAb except 7A1; when compared with rDer p 2 for IgE binding, rEur m 2.0101 gave a correlation coefficient of r (2) = 0.68. Molecular modeling revealed that Eur m 2 and the storage mite homologs Lep d 2 and Tyr p 2 retain the tertiary fold of Der p 2. Eur m 2 has a conserved surface, whereas Lep d 2 and Tyr p 2 present most of the amino acid substitutions on this surface. Lep d 2 and Tyr p 2 did not react with mAb or with sera from patients with IgE to Dermatophagoides species.

CONCLUSION

The isoform substitutions of rDer p 2 can be distinguished by mAb. The allergenic cross-reactivity between Der p 2, Der f 2, and Eur m 2 is a direct result of the conserved antigenic surface, whereas the lack of cross-reactivity with Lep d 2 and Tyr p 2 is a result of the multiple substitutions across this surface.

Identification and characterization of a novel benzo[a]pyrene-derived DNA adduct

The aim of this study was to generate and identify a novel benzo[a]pyrene (BP)-derived DNA adduct found both in vitro and in vivo. To date, the majority of studies have focused on N(2)-[10 beta(7 beta,8a,9a-trihydroxy-7,8,9,10-tetrahydrobenzo[a]pyrene)yl]-deoxyguanosine (anti-BPDE-dG), the major adduct generated following bioactivation of BP. However, a second adduct is also formed following bioactivation of BP which has been speculated to result from further metabolism of 9-OH-BP. In order to identify this second reaction pathway, the ultimate DNA binding species, and the DNA base involved, we have synthesized and characterized a dG-derived DNA adduct arising from further bioactivation of 9-OH-BP in the presence of rat liver microsomes. Analysis of the adducted nucleotides was conducted using both the (32)P-postlabeling assay and capillary electrophoresis-mass spectrometry (CE-MS).

Sequence polymorphisms and antibody binding to the group 2 dust mite allergens

BACKGROUND

The group 2 allergens Der p 2, Der f 2 and Eur m 2 are 14-kD proteins with > 80% sequence identity. Isoforms within each genus have been identified which differ by 3-4 amino acids. The aim of this study was to investigate the importance of these substitutions to antibody binding.

METHODS

Recombinant allergens were expressed and purified from Escherichia coli. ELISA and skin testing were used to evaluate antibody binding. Molecular modeling of the tertiary structure was preformed to examine the location of substitutions.

RESULTS

The three Der f 2 isoforms and two of three of the Der p 2 isoforms reacted with all monoclonal antibodies (mAb). Der p 2.0101, the isoform with aspartate at position 114, bound all mAb except 1D8. Substitution of asparagine for aspartate restored binding of rDer p 2.0101 to mAb 1D8 and increased the correlation coefficient for IgE binding from 0.72 to 0.77. The three Der p 2 isoforms showed comparable skin test reactivity to nDer p 2 and commercial extract. rEur m 2.0101 bound to all mAb except 7A1 and when compared with rDer p 2 for IgE binding, r(2) = of 0.58 (n = 72). Lep d 2 did not react with mAb or with Dermatophagoides spp. allergic sera. Modeling revealed that Eur m 2, Lep d 2 and Tyr p 2 retain the tertiary fold of Der p 2 and the substitutions are on the surface.

CONCLUSIONS

mAb could distinguish isoform substitutions. IgE binding showed a good correlation among all isoforms, thus the recombinant allergens are useful for diagnosis.

1,2-dithiole-3-thione and its structural analogue oltipraz are potent inhibitors of dibenz

Dithiolethiones are currently one of the most promising classes of cancer chemopreventive agents that exhibit antitumorigenic properties at numerous organ sites against several classes of carcinogens. In the current study, we examined the effects of 2 dithiolethiones, 1,2-dithiole-3-thione (D3T) and its structural analogue oltipraz, on DNA adduction induced by the potent mammary carcinogen dibenzo-[a,l]pyrene (DBP) in vivo. Female Sprague-Dawley rats were provided dietary D3T and oltipraz (500 ppm each) for I week followed by a single intragastric dose of DBP (8 micromol/kg body weight) and killed 5 days later. D3T inhibited DBP-DNA adduction from 78% to 82% in all tissues examined, while oltipraz was equally effective in the lung and liver but less effective in the mammary glands, inhibiting DBP-DNA adduction by nearly 60%. These data coupled with their broad anti-tumor specificity support the use of D3T and oltipraz as cancer-preventive agents in clinical trials.

Dynamic regulation of prothoracic gland ecdysteroidogenesis: Manduca sexta recombinant prothoracicotropic hormone and brain extracts have identical effects

Multiple assays were conducted in order to determine if the recently available recombinant prothoracicotropic hormone (rPTTH) from Manduca sexta is identical, or similar, to the natural hormone and if results from its use in a variety of assays confirm, or are inconsistent with, previous studies over the past 20years on PTTH action using brain extract. Brain extracts and rPTTH showed similar, if not identical, effects on the cell biology of Manduca prothoracic gland cells with the following results: increased levels of cAMP (adenosine 3':5' cyclic monophosphate) synthesis; requirement for extracellular Ca(2+) in in vitro studies; ecdysteroidogenesis stimulation in vitro; stimulation of general and specific protein synthesis; immunocytochemical identification of the two lateral cells in each brain hemisphere as the source of PTTH (the prothoracicotropes); the ability of antibodies to rPTTH to inhibit ecdysteroidogenesis stimulation in vitro; and the multiple phosphorylation of the ribosomal protein S6. The data revealed that brain extract and rPTTH show equivalent effects in all of the assays, indicating that this rPTTH is the natural PTTH of Manduca and that the data generated with brain extracts over the past two decades are indeed relevant.

System analysis of the flow/pressure response of rotodynamic blood pumps

Design of a rotodynamic blood pumping system to have a suitable, controllable output is a key configuration issue. This study evaluates the benefits of selecting the impeller running specific speed, motor speed-torque line, and pump operating logic to jointly combine into a suitable characteristic. In this study, a "constant" flow for a given choice of control parameter value was the selected objective. The operating condition selected for analysis was chosen to be typical of an implanted, chronic support pump. Open-loop operation, fixed torque, fixed power, and fixed power/rpm2 ratio were combined with choices of impeller diameter and speed and motor speed-torque line. It was found that setting the running specific speed at a higher value than that associated with the best efficiency point resulted in a much more controllable pump. Overall efficiency was only slightly penalized for the model impeller chosen. Power/rpm2 control followed by torque control were most effective. With these control modes, motor characteristics were not critical.

DNA adduct formation and persistence in rat tissues following exposure to the mammary carcinogen dibenzo[a,l]pyrene

Dibenzo[a,l]pyrene (DBP), an environmentally significant polycyclic aromatic hydrocarbon (PAH), is one of the most potent carcinogens with greater carcinogenicity in rodent mammary glands and skin than 7,12-dimethylbenz[a]anthracene or benzo[a]pyrene, respectively. In this study, we have examined the formation and persistence of stable DNA adducts in rats administered a carcinogenic intramammillary (i.m.) dose of DBP (0.25 micromol/gland). 32P-post-labeling analysis of mammary epithelial DNA 6 h, and 2, 5 and 14 days post-treatment produced one major (approximately 30%) and at least six minor adducts. Non-target tissue DNA (lung, heart, bladder and pancreas) also showed essentially the same adduct pattern as did mammary DNA, except liver which resulted in four additional adduct spots. The mammary DNA was most adducted (2640 +/- 532 adducts/10(9) nucleotides) on day 5 while the other tissue DNAs had 10- to 65-fold lower adduct levels (lung > liver > heart > bladder > pancreas). Adduct levels continued to increase at all time points examined for all tissues, except mammary tissue which showed a decline ( approximately 40%) on day 14. Chromatographic comparison with adducts formed in vitro by reaction of syn- and anti-DBP-11, 12-diol-13,14-epoxides (DBPDEs) with DNA and individual nucleotides indicated that the in vivo adducts were deoxyadenosine- and deoxyguanosine-derived, formed by interaction with both the anti- and syn-isomers; the adenine-derived adducts comprised 60-75% of the total adducts. However, the liver-specific DNA adducts (nos 8-11) were not derived from any of the DBPDE isomers. Our data show: (i) significantly higher DBP-DNA adduction in mammary tissue as compared with non-target tissues, which is consistent with its mammary carcinogenicity; (ii) adenine is highly reactive towards DBP metabolites as has been observed for many other PAHs; and (iii) the peak binding of DBP with DNA was shifted beyond 14 days for the non-target tissues by i.m. route of exposure.

Determining efficacy of cancer chemopreventive agents using a cell-free system concomitant with DNA adduction

The large (>2000) and expanding number of natural and synthetic agents with potential cancer chemopreventive properties renders it economically and physically impossible to test each of these agents for their efficacy in the widely accepted 2-year animal bioassay and clinical trials. Therefore, there is a growing need for relevant short-term screening tests to study these compounds such that only the most efficacious ones undergo extensive long-term studies. We have previously reported in a pilot study that the use of a microsome-mediated test system concomitant with DNA adduction is a pertinent and relevant model for rapidly studying the efficacy and mechanisms of cancer chemopreventive agents. We have extended this study to investigate 26 additional agents for their potential chemopreventive abilities by studying their effects on microsome-mediated benzo[a]pyrene (BP)-DNA adduction. These agents had differential effects on the two major adducts of BP-DNA, i.e., BP-7,8-diol-9,10-epoxide (BPDE)-deoxyguanosine (dG) and 9-OH-BP-dG-derived adducts. These agents were therefore categorized into five classes. Three test agents (ellagic acid, genistein and oltipraz) were strong inhibitors of both adducts. These agents diminished BP-DNA adduction by 65-95% and were categorized as Class I agents. Six other agents (benzyl isocyanate, R(+)-1-phenylethyl isocyanate, linoleic acid ethyl ester, (+)-biotin, indole-3-carboxylic acid and beta-carotene) moderately inhibited both BP-DNA adducts (25-64%); these compounds were identified as Class II agents. Six additional test agents inhibited only one adduct selectively and nine others were ineffective; these agents were categorized as Class III and Class IV, respectively. Interestingly, seven test agents enhanced BPDE-dG or 9-OH-BP-dG or both adducts and were categorized as Class V agents. Four of these Class V agents concomitantly inhibited BPDE-dG while enhancing 9-OH-BP-dG. This emphasizes the importance of studying individual DNA adducts in contrast to total DNA binding. In conclusion, Class I and Class II agents may be good candidates for further chemoprevention studies.

Numeric flow simulation for an innovative ventricular assist system secondary impeller

The secondary impeller of the Cleveland Clinic Foundation Innovative Ventricular Assist System heart pump is designed to pump the blood from the journal bearing through the annulus back to the discharge to rejoin the main flow. It is crucial, however, that the amount of hemolysis and potential for thrombus formation is minimized. Based on our earlier computational fluid analysis of the initial design, an improved secondary impeller has been proposed. The objective of this work was to analyze the flow with the new impeller configuration by computational fluid dynamics and to find out where in the geometry hemolysis becomes high, as well as where the potential for thrombosis exists. The present work includes: 1) visualizing the 3-dimensional flow pattern in the secondary impeller cavity, 2) investigating the tip clearance effect, and 3) estimating the shear stress distribution as a measure for blood damage caused in the secondary impeller cavity.

Numeric modeling of the cardiovascular system with a left ventricular assist device

A numeric model consisting of a lump-parameter cardiovascular system (CVS) model and a model for the Cleveland Clinic Implantable Ventricular Assist System (IVAS), a nonpulsatile rotary pump designed to augment the failing left ventricle, are described in this paper. The purposes of this study were to 1) observe the hemodynamic interactions between CVS and IVAS under various physiologic and pathophysiologic conditions running at different speeds; and 2) allow testing and optimization of various IVAS control algorithms. An existing numeric model of CVS (24 coupled differential equations, representing all cardiac chambers and systemic and pulmonary vasculature) was modified to add the IVAS pump as an auxiliary chamber between the left ventricle and aorta with pressure-flow-speed characteristics derived from in vitro testing. Simulations were conducted for ventricles with normal and abnormal systolic and diastolic dysfunction at different exercise levels with the pump running at various speeds. Computer simulations show that 1) numeric modeling is useful for predicting hemodynamic response of CVS to IVAS in various circumstances; 2) IVAS results in normalization of cardiac output, especially in failing hearts, although with reduced pulse pressure; and 3) various control algorithms allowing adaptation of IVAS to physiologic demands of CVS could be developed based on the simulation study.

Fibromyalgia syndrome

Fibromyalgia syndrome (FMS) is a more common a condition than previously estimated. The most recent estimates are that 3 to 6 million patients have been diagnosed with FMS. The ACR criteria, established in 1990, provide the primary care provider with definitive subjective and objective findings that have shown to be 88% accurate in their ability to diagnose patients with the syndrome. There is no cure for FMS. It is a chronic condition, but patients quality of life can be improved when fatigue and pain are reduced. The institution of a plan that is developed collaboratively by the patient and the provider is the essence of successful symptom management. The hallmarks of the management plan include: improving the quality of sleep through the judicious use of medications that boost the body's level of serotonin (therefore reducing fatigue), and reducing pain through complimentary modalities such as exercise, physical therapy, relaxation techniques, massage, and biofeedback.

High efficiency magnetic bearing for a rotary blood pump

Mohawk Innovative Technology, Inc. (MiTi; Albany, NY) and the Cleveland Clinic Foundation (Cleveland, OH) have been engaged in a joint project to develop a new, high efficiency magnetic bearing for use in a rotary blood pump. Such a bearing would have some advantages with respect to permitting large, low shear clearances and avoiding crevice-like pivot interfaces and surface wear related issues. While magnetically suspended blood pumps have been demonstrated, other prototypes reported in the literature consume 5-15 W of power to energize the bearing. The MiTi bearing has been prototyped and tested. The design is a hybrid configuration, radially passive and axially active. The rotor-and-bearing system has been run in air and in blood analog solution, in all orientations. Measurements show a bearing power consumption below 0.5 W. Vibration peaked at 0.2 g in blood analog solution; frequency analysis indicated that this was primarily related to motor design features. Measured displacements from the equilibrium position were less than 0.005 cm. Based on this highly successful bearing prototype, an integrated pump/bearing system is now being developed.

Stable blood lubricated hydrodynamic journal bearing with magnetic loading

The Cleveland Clinic Foundation's Innovative Ventricular Assist System (IVAS) is distinguished by the use of a special hydrodynamic journal bearing to support the rotating assembly of the blood pump. In a permanently implanted blood pump, this bearing's characteristics of long life and high reliability are of paramount importance. In addition, this bearing's inherent self-pumping flow and the axial through flow caused by an imposed end-to-end pressure difference provides good washing, thus guarding against deposition. The basic computer analysis and preliminary testing results of this bearing were previously presented. This article reports the ongoing studies (both analytic and in vitro tests) on this innovative bearing as a component of the IVAS in general, with particular emphasis on its stable operating characteristics and reliability. The absence of vibration attributable to hydrodynamic instabilities related to the thick fluid film are both calculated and demonstrated during testing. A stable operating center of the rotor is shown to be inherent under magnetic side loads and resulting hydrodynamic bearing forces. A low shear as a result of large fluid-film thicknesses has been calculated, and low hemolysis has been shown by in vitro testing. Several unique design features of the bearing are believed to be responsible for this high level of performance.

Reactivity to recombinant house-dust-mite allergens in asthma and rhinitis in a tropical environment

BACKGROUND

House-dust mites contain components that are allergenic in mite-sensitive patients, and a number of these have been produced in recombinant form.

METHODS

In the present study, we evaluated by skin prick testing the positivity to native Der p 2 and recombinant Der p 2, Der p 5, and Der p 7 allergens of Dermatophagoides pteronyssinus in patients with rhinitis, asthma, or a combination of these diseases, who were positive to whole-mite extract.

RESULTS

In all patients, the positivity to both native and recombinant Der p 2 was high. In patients with either rhinitis or asthma, the reactivity to Der p 5 and 7 was significantly lower than to Der p 2. However, in patients with combined disease, the positivity to the minor allergens was almost as high as that to Der p 2.

CONCLUSIONS

These results raise the question of whether patients with combined allergic rhinitis and asthma, when compared to those with either of these diseases alone, are predisposed to react to a wider range of mite allergens, or, inversely, whether patients who respond to the minor allergens are more susceptible to suffering the combined disease.

Effect of cancer chemopreventive agents on microsome-mediated DNA adduction of the breast carcinogen dibenzo[a,l]pyrene

Due to the large and expanding number of potential cancer chemopreventive agents, there is an increasing need for short term tests to study the efficacy and mechanisms of these agents. In this study, we have employed a microsome-mediated test system to study the effect of several suspected chemopreventive agents on the DNA adduct formation capacity of the potent mammary carcinogen, dibenzo[a,l]pyrene (DBP). Bioactivation of DBP by Aroclor 1254-induced rat liver microsomes in the presence of calf thymus DNA (300 microg/ml) resulted in the formation of one major and six other prominent DNA adducts (324 adducts/10(7) nucleotides). These adducts were previously determined to be deoxyadenosine (dA) and deoxyanosine (dG)-derivatives of both anti- and syn-DBP-11,12-diol-13,14-epoxides (DBPDE). Intervention with ellagic acid, chlorophyllin, benzyl isocyanate (BIC), oltipraz or genistein (150 microM) strongly diminished DBP-DNA adduction by > or = 75%. Linoleic acid, curcumin and butylated hydroxytoluene (BHT) also significantly inhibited DBP DNA adduction (26-46%) while N-acetylcysteine (NAC) had no effect. Moreover, nonenzymatic studies with anti- and syn-DBPDE isomers revealed that chlorophyllin, ellagic acid, BIC and BHT may be inhibiting DBP-DNA adduction in an enzymatic-independent manner since these agents diminished DBPDE-DNA adduction by 30-75%. Genistein, oltipraz and curcumin did not diminish DBPDE-DNA adduction and therefore most likely require the presence of the microsomal subcellular fraction to inhibit DBP-DNA adduction.

Selection and evaluation of blood- and tribologically compatible journal bearing materials

A critical issue in the Cleveland Clinic Foundation (CCF) Innovative Ventricular Assist System (IVAS) blood pump is the selection of materials for the blood-lubricated journal bearing. Under normal operating conditions, the journal bearing geometry creates a thick blood film that separates the rotating and stationary surfaces. However, since start-up and certain transients could cause temporary contact, the material pair selected for these surfaces must be both tribologically and blood compatible. Combinations of two biocompatible alloys were tested: a titanium-zirconium-niobium alloy (Ti-13Zr-13Nb) and a zirconium-niobium alloy (Zr-2.5Nb). A standard pin-on-disk tester was used, with the contact surfaces lubricated by glycerol/saline mixtures simulating the viscosity range of blood. One test series evaluated start-up conditions; the other modeled a high-speed rub that might occur if the fluid film broke down. Results showed that the preoxidized Zr-2.5Nb pin/Ti-13Zr-13Nb disk combination was superior at all sliding velocities; a self-mated Zr-2.5Nb pair also showed promise. The oxide film on a self-mated Ti-13Zr-13Nb pair, and a Ti-13Zr-13Nb pin and Zr-2.5Nb disk combination did not show adequate wear life. More work remains to explain distinct performance differences of certain combinations, with more data needed on mechanical properties of thin, hard coatings on softer metal substrates.

Blood flow analysis for the secondary impeller of an IVAS heart pump

The rotodynamic heart pump (IVAS), designed by the Cleveland Clinic Foundation, includes a secondary flow path along the journal bearing, through a secondary impeller, and over the rotor outer surface. The flow behaviors of the blood through the journal bearing and the secondary impeller are investigated by a computational fluid dynamics method that solves the 3-dimensional Navier-Stokes equations using a new solution algorithm. Results of the analyses include: 1) the blood flow patterns within the journal bearing, 2) the effect of the non-uniform bearing clearance on the flow patterns of the impeller cavity, 3) the flow patterns around a secondary impeller blade that include effects of tip clearance and the gap between the blade and the inner or outer side wall, 4) effects of the blade angles on the secondary impeller performance, and 5) the shear stress distribution.

The analysis, design, and testing of a blood lubricated hydrodynamic journal bearing

The Cleveland Clinic Foundation's Innovative Ventricular Assist System (IVAS) uses a hydrodynamic journal bearing to support the rotating assembly of the blood pump. Bearing dimensions are chosen so that a stable film of lubricant develops and separates stationary and rotating pump surfaces during operation. This bearing type provides several advantages for a permanently implanted device, including essentially no wear for very long life and very high reliability, as well as a self pumping action that generates circumferential wash flow and thus lowers the risk of bearing associated deposition. However, these advantages are accompanied by design issues not encountered with typical journal bearing, such as low shear stress, bearing ends that are not at atmospheric pressure, and low radial bearing loads. To address these issues, several concepts for a hydrodynamic blood bearing were designed and analyzed using a special computer code to perform parametric studies. This design analysis code was developed to define optimum bearing performance under selected load and speed ranges and within practical tolerances. Results showed the range of dimensions and conditions over which an effective, reliable, blood lubricated journal bearing can be designed. Subsequent bench testing has validated the theoretical conclusions and shown this bearing type to be very robust in a blood pump application.

Development of a 6 x 18 inch rheology tunnel for experimental fluid dynamics investigation

The Ohio State University (OSU) and the Cleveland Clinic Foundation (CCF) developed a 6 x 18 inch low velocity Rheologic Research Tunnel to do flow visualization and other experimental fluid studies, particularly on scaled-up models of cardiovascular devices, such as the CCF's Innovative Ventricular Assist System. The large test section (TS) permits detailed data to be obtained that would be inaccessible with a smaller test prototype. A particular feature of the OSU-CCF program is the use of a non-Newtonian blood analog (NNBA), so the effect of the shear-thinning behavior of blood on the local development of separation, stagnation, and flow patterns can be studied. The TS can simulate a pressure driven slit flow of 6 x 18 in., or the external flow around a vane or blade having an aspect ratio of 1. Maximum pressure is 8.5 psig, while the maximum velocity is 21.7 in/sec. The fluid supply tank has a capacity of 500 gal of NNBA and, with its associated filtration and circulation systems, can be adapted to studies of large transparent models better studied outside the TS. Using 2 pumps, flow rates of 98-610 gal/min can be provided. Instrumentation includes thermistors, a 48 port pressure scanner with pressure transducers, a data acquisition system, and a digital video camera. Dye and hydrogen bubble systems have been developed. Development of such a facility presents problems not encountered in more typical water tables or wind tunnels. These include fundamental issues such as providing a uniform flowfield; practical issues with respect to priming, operating, and obtaining data from the system; and safety considerations. For the very large volume of NNBA, a xanthan gum solution is used, whose shear-thinning behavior depends not only on concentration, but also on age and prior shear history. The lessons learned are presented, permitting others to efficiently develop systems suitable to their testing needs.

Flow analysis of the Cleveland Clinic centrifugal pump

An implantable ventricular assist blood pump is being developed by the Cleveland Clinic Foundation in cooperation with the NASA Lewis Research Center. At the nominal design condition, the pump provides blood flow at the rate of 5 L/min at a pressure rise of 100 mmHg and a rotation speed of 3000 RPM. Bench testing of the centrifugal pump in a water/glycerin mixture has provided flow and pressure data at several rotative speeds. A one-dimensional empirically based pump flow analysis computer code developed at NASA Lewis Research Center has been used in the design process to simulate the flow in the primary radial pump stage. The computer model was used to size key impeller and volute geometric parameters that influence pressure rise and flow. Input requirements to the computer model include a simple representation of the pump geometry. The model estimates the flow conditions under design and off-design operating conditions at the impeller leading and trailing edges, and the volute inlet and exit. Output from the computer model is compared to flow and pressure data obtained from bench testing.

Design of a DSP controller for an innovative ventricular assist system

The design and development of the digital signal processor controller for an innovative ventricular assist system is presented. A DSP56005 is used as the central processor, with other peripheral components. System hardware and software were developed through the advanced development system, and stand alone operation of the system was also accomplished. Two different control modes--current control mode and speed control mode--were developed and investigated. Performance of efficiency and dynamic response were examined through experimental testing.