Evaluation of the effect of ozone disinfection on forensic identification of blood, saliva, and semen stains

Good laboratory practice minimizes the biological hazard posed by potentially infectious casework samples. In certain scenarios, when the casework sample is contaminated with highly contagious pathogens, additional safety procedures such as disinfection might be advised. It was previously proven that ozone gas treatment does not hamper STR analysis, but there is no data on how the disinfection affects other steps of the forensic analysis. In this study, we aimed to assess the interference of ozone disinfection with forensic tests used to identify biological stains. A dilution series of blood, saliva, and semen samples were pipetted onto cotton fabric and let completely dry. Half of the samples were subjected to ozone treatment, while the rest served as controls. All the samples were tested with specific lateral flow immunochromatographic assays and for specific RNA markers with quantitative real-time PCR. Additionally, luminol test was carried out on blood spots, Phadebas® Amylase Test on saliva stains, and semen stains were examined with STK Lab kit and light microscope following Christmas Tree or Hematoxylin-Eosin staining. Ozone treatment had no detrimental effect on the microscopic identification of sperm cells. Undiluted blood samples were detected with luminol and immunoassay, but at higher dilution, the sensitivity of the test decreased after disinfection. The same decrease in sensitivity was observed in the detection of semen stains using STK Lab kit from STK® Sperm Tracker, and in the case of the immunoassay specific for prostate-specific antigen (PSA). Ozone treatment almost completely inhibited the enzymatic activity of amylase. The sensitivity of antibody-based detection of amylase was also greatly reduced. RNA markers showed degradation but remained detectable in blood and semen samples after incubation in the presence of ozone. In saliva, the higher Ct values of the mRNA markers were close to the detection limit, even before ozone treatment.

Mimicking Horseradish Peroxidase and NADH Peroxidase by Heterogeneous Cu2+-Modified Graphene Oxide Nanoparticles

Cu²⁺-ion-modified graphene oxide nanoparticles, Cu²⁺-GO NPs, act as a heterogeneous catalyst mimicking functions of horseradish peroxidase, HRP, and of NADH peroxidase. The Cu²⁺-GO NPs catalyze the oxidation of dopamine to aminochrome by H₂O₂ and catalyze the generation of chemiluminescence in the presence of luminol and H₂O₂. The Cu²⁺-GO NPs provide an active material for the chemiluminescence detection of H₂O₂ and allow the probing of the activity of H₂O₂-generating oxidases and the detection of their substrates. This is exemplified with detecting glucose by the aerobic oxidation of glucose by glucose oxidase and the Cu²⁺-GO NP-stimulated chemiluminescence intensity generated by the H₂O₂ product. Similarly, the Cu²⁺-GO NPs catalyze the H₂O₂ oxidation of NADH to the biologically active NAD⁺ cofactor. This catalytic system allows its conjugation to biocatalytic transformations involving NAD⁺-dependent enzyme, as exemplified for the alcohol dehydrogenase-catalyzed oxidation of benzyl alcohol to benzoic acid through the Cu²⁺-GO NPs-catalyzed regeneration of NAD⁺.

Enhanced competitive chemiluminescent enzyme immunoassay for the trace detection of insecticide triazophos

A direct competitive chemiluminescent enzyme immunoassay (CLEIA) for triazophos was developed, which was based on the anti-THHe IgG monoclonal antibody and a heterogeneous enzyme tracer (THHu-HRP). Several components of chemiluminescent enhanced solution (CES) were optimized. The results showed that 1 mM of p-iodo-phenol, 0.625 mM of luminol, and 4 mM of H(2)O(2) had the best performance. Based on the study of CES, the influence of several factors (assay buffer, blocking substance, and solvent) on the immunoassay was investigated. The sensitivity for detection, IC(50) value was 0.87 ng/mL at a practical working concentration range between 0.04 ng/mL and 5 ng/mL and the limit of detection for triazophos was 0.063 ng/mL. The average recovery of triazophos added to lettuce, carrot, apple, water, and soil were 78.71%, 67.52%, 118.3%, 117.2%, and 122.0%, respectively. Finally, comparison between the methods of CLEIA and high-performance liquid chromatography-tandem mass spectrum (HPLC-MS/MS) was performed. The results obtained from CLEIA were in agreement with those of HPLC-MS/MS.

Noninvasive assessment of localized inflammatory responses

Inflammatory diseases are associated with the accumulation of activated inflammatory cells, particularly polymorphonuclear neutrophils (PMNs), which release reactive oxygen species (ROS) to eradicate foreign bodies and microorganisms. To assess the location and extent of localized inflammatory responses, L-012, a highly sensitive chemiluminescent probe, was employed to noninvasively monitor the production of ROS. We found that L-012-associated chemiluminescence imaging can be used to identify and to quantify the extent of inflammatory responses. Furthermore, regardless of differences among animal models, there is a good linear relationship between chemiluminescence intensity and PMN numbers surrounding inflamed tissue. Depletion of PMNs substantially diminished L-012-associated chemiluminescence in vivo. Finally, L-012-associated chemiluminescence imaging was found to be a powerful tool for assessing implant-mediated inflammatory responses by measuring chemiluminescence intensity at the implantation sites. These results support the use of L-012 for monitoring the kinetics of inflammatory responses in vivo via the detection and quantification of ROS production.

On-capillary Chemiluminescence Detection for Capillary Electrophoresis with a Single Capillary

On-capillary chemiluminescence detection for capillary electrophoresis with a single capillary was reported. A hole (about 30 microm diameter) was made on the capillary wall at about 50.5 cm from the inlet end. Hydrogen peroxide solution could enter the capillary from the hole, and mixed with luminol and copper(II) to produce chemiluminescence. The chemiluminescence was detected by a PMT under the hole. Several factors that influenced chemiluminescence intensity were investigated. The detection limits for luminol and N-(4-aminolbutyl)-N-ethylisoluminol (ABEI) were 1 x 10(-11) and 2 x 10(-10) mol L(-1), respectively. The method features simple construction and no dead volume.

Electrogenerated chemiluminescence of luminol in neutral and alkaline aqueous solutions on a silver nanoparticle self-assembled gold electrode

The electrochemiluminescence (ECL) behaviour of luminol on a silver nanoparticle self-assembled gold electrode in neutral and alkaline solutions was investigated using conventional cyclic voltammetry (CV). The silver nanoparticle self-assembled gold electrode exhibited excellent ECL properties for the luminol ECL system. In neutral solutions, four ECL peaks (ECL-1-ECL-4) were observed at 0.73, 1.15, -0.46 and -1.35 V (vs. SCE), respectively. The intensities of these peaks were enhanced significantly compared with those on a bulk gold electrode and a gold nanoparticle self-assembled gold electrode. It was found that ECL-1 and ECL-2 on a silver nanoparticle-modified electrode were about 1000 and 1770 times stronger than those on a bare Au electrode and were about 17 and 15 times stronger than those on a gold nanoparticle-modified electrode, respectively. In alkaline solutions, four ECL peaks were also observed that were much stronger than those in neutral solutions, and ECL-1 and ECL-2 were enhanced by about three orders and one order of magnitude compared with those on a bare Au electrode and on a gold nanoparticle self-assembled electrode, respectively. Moreover, the silver nanoparticle-modified electrode exhibited good stability and reproducibility for luminol ECL. These peaks were found to depend on a number of factors, including silver nanoparticles on the surface of the modified electrode, potential scan direction, scan rate, scan range, the presence of O2 or N2, pH values, the concentrations of NaBr and luminol, and buffer solutions. The emitter of the ECL was confirmed as 3-aminophthalate by analysing the CL spectra. The surface state of the silver nanoparticle self-assembled electrode was characterized by scanning electron microscopy (SEM) and the interface property of the electrode was studied by electrochemical impedance spectroscopy (EIS). A mechanism for the formation of these ECL peaks is proposed. The results demonstrate that luminol has excellent ECL properties, such as strong ECL intensity and good reproducibility on a silver nanoparticle-modified gold electrode, in both neutral and alkaline solutions, which is of great potential in analytical applications.

Resveratrol Improves Ischemia/Reperfusion-Induced Oxidative Renal Injury in Rats

BACKGROUND

The present study was designed to examine whether resveratrol, a potent antioxidant, protects against renal ischemia-reperfusion (I/R) injury.

METHODS

Wistar albino rats were unilaterally nephrectomized and subjected to 45 min of renal pedicle occlusion followed by 6 h of reperfusion. Resveratrol (RVT, 30 mg/kg, i.p.) or vehicle was administered twice, at 30 min prior to ischemia and immediately before the reperfusion period. At the end of the reperfusion period, rats were decapitated and kidney samples were taken for histological examination or determination of levels of renal malondialdehyde (MDA), an end product of lipid peroxidation; glutathione (GSH), a key antioxidant; and myeloperoxidase (MPO) activity, an index of tissue neutrophil infiltration. Formation of reactive oxygen species in hepatic tissue samples was monitored by using chemiluminescence (CL) technique with luminol and lucigenin probes. Renal tissue collagen content as a fibrosis marker was also determined, while serum creatinine and urea concentrations were measured for the evaluation of renal function. Tumor necrosis factor-alpha (TNF-alpha ) and lactate dehydrogenase (LDH) were also assayed in serum samples.

RESULTS

Ischemia/reperfusion caused a significant decrease in tissue GSH level, which was accompanied by significant increases in the renal luminol and lucigenin CL values, MDA level, MPO activity and collagen content. Similarly, serum creatinine and BUN levels, as well as LDH and TNF-alpha, were elevated in the I/R group as compared to control group. On the other hand, resveratrol treatment reversed all these biochemical indices, as well as histopathological alterations that were induced by I/R.

CONCLUSIONS

Findings of the present study suggest that resveratrol exerts renoprotective effects via its radical scavenging and antioxidant activities, which appear to involve the inhibition of tissue neutrophil infiltration.

Applications of the luminol chemiluminescent reaction in analytical chemistry

This critical review discusses the results published between 2000 and 2005 on the development of analytical systems based on the luminol chemiluminescent and electrochemiluminescent reactions. An increasing number of non-specific detection systems based on the enhancing, inhibiting or catalysing effect of a large range of compounds have been published. Possible detected compounds and their concomitant presence in samples are discussed. Chemiluminescent and electrochemiluminescent reactions were also found to merge in biochip and microarray development as a possible substitute to the well-established but hardly quantitative fluorescent detections.

Determination of thyroxine in pharmaceuticals using flow injection with luminol chemiluminescence inhibition detection

A simple flow injection method is reported for the determination of thyroxine, based on its inhibition effect on luminol-iron(II) chemiluminescence in alkaline medium in the presence of molecular oxygen. The detection limits (2s) for d- and l-thyroxine are 0.08 and 0.1 mg/L, respectively, with a sample throughput of 100/h. The calibration data for d- and l-thyroxine over the range 0.2-1.0 mg/L gives correlation coefficients (r(2)) of 0.9915 and 0.984 with relative standard deviations (RSD; n = 4) in the range 1.2-2.8%. The effects of some organic compounds was studied on luminol-iron(II) CL system for thyroxine determination. The method was applied to pharmaceutical thyroxine tablets and the results obtained (in the range 50.5 +/- 2.0-51.6 +/- 1.2 microg l-thyroxine/tablet) were in reasonable agreement with the value quoted.

Ghrelin against alendronate-induced gastric damage in rats

Alendronate sodium, a primary amino bisphosphonate, is widely used in the treatment of various diseases that are associated with bone resorption, such as postmenopausal osteoporosis and Paget's disease of bone. Although the adverse effects of biphosphonates on the gastrointestinal system have been demonstrated in experimental and clinical studies, the exact mechanisms underlying this damage are not clear yet. Ghrelin, a 28 amino acid peptide produced predominantly by the stomach, was shown to exert a potent protective action on the stomach of rats exposed to ethanol or stress. Our objective was to evaluate the possible anti-oxidant and anti-inflammatory effects of ghrelin against alendronate-induced gastric damage. Wistar albino rats were administered alendronate (20 mg/kg) by gavage for 4 days, along with either ghrelin (10 ng/kg per day) or saline given i.p. After decapitation, stomach tissues were removed for the determination of malondialdehyde (MDA) and glutathione (GSH) levels, myeloperoxidase (MPO) activity and tissue collagen content, while the extent of tissue damage was analyzed microscopically. Formation of reactive oxygen species was determined by chemiluminesence using a luminol probe in fresh gastric tissues. Serum tumor necrosis factor (TNF-alpha) and lactate dehydrogenase levels were assessed in trunk blood. Oral administration of alendronate-induced significant gastric damage, accompanied by increased MPO activity, collagen content, MDA and luminol levels (P < 0.01-P < 0.001), while tissue GSH was decreased (P < 0.01). On the other hand, ghrelin treatment reversed these alterations (P < 0.05-P < 0.001) as well as elevating serum TNF-alpha levels significantly (P < 0.001). The findings of the present study suggest that alendronate induces oxidative gastric damage by a local irritant effect, and ghrelin ameliorates this damage by its possible antioxidant and anti-inflammatory properties.

Assessment of the antioxidant activities of Brazilian extracts of propolis alone and in topical pharmaceutical formulations

The antioxidant activity of extracts of propolis and of formulations added with these extracts were measured by scavenging different radicals in different systems. For the ethanolic extract of propolis (EEP) and the glycolic extract of propolis (GEP) the IC50 observed were respectively of 0.024 and 0.035 microL/mL in scavenging hydroxyl radical, 0.016 and 0.012 microL/mL in inhibiting lipid peroxidation, 0.22 and 0.24 microL/mL in inhibiting chemiluminescence produced in the H2O2/luminol/horseradish peroxide (HRP) system and about 0.005 microL/mL for both extracts in inhibiting chemiluminescence produced in the xanthine/luminol/xanthine oxidase (XOD) system. The antioxidant activity of extracts of propolis in the formulations was not able to be assessed neither using the deoxyribose assay, since the formulation components interfered in the assay measurements, nor using chemiluminescence in the H2O2/luminol/HRP system, since this method did not show to be sensitive for the extract of propolis evaluation. However, the antioxidant activity of extracts of propolis could be successfully evaluated in the formulations using both lipid peroxidation and chemiluminescence generated in the xanthine/luminol/XOD system inhibitions.

The enhanced electrochemiluminescence of luminol on the nickel phthalocyanine modified electrode

A glassy carbon electrode (GCE) modified with nickel(II) tetrasulfophthalocyanine (NiTSPc) and Nafion was used for the investigation of the catalytic oxidation of luminol. The modified electrode was found to much more effectively improve the emission of electrochemiluminescence(ECL) of luminol in a solution containing hydrogen peroxide. The enhanced ECL signal corresponded to the catalytic oxidation of both luminol and H(2)O(2) by NiTSPc. Attached Ni(II) on GCE was oxidised to Ni(III) and then used as the catalyst for the chemiluminescence of luminol. The enhanced stability of the ECL signal with Nafion would mainly result from the prevention of the dissolution of NiTSPc and the adsorption of the oxidation product of luminol on the electrode surface. The proposed method enables a detection limit for luminal of 6.0 x 10(-8) mol L(-1) to be achieved in the presence of H(2)O(2) in the neutral solution. The enhanced ECL intensity had a linear relationship with the concentration of luminol in the range of 1.0 x 10(-7)-8.0 x 10(-6) mol L(-1).

Chemiluminescence determination of amikacin based on the inhibition of the luminol reaction catalyzed by copper

A simple and sensitive method has been proposed for the amikacin sulphate determination. It is based on the inhibition of the chemiluminescence (CL) emission generated from the oxidation of luminol in alkaline medium by H2O2 catalyzed by Cu(II), due to the interaction caused by amikacin, which forms a robust complex with the catalyst. The optimization of the experimental and instrumental variables affecting this CL inhibition effect has been carried out using statistical models, based on the application of two-level full factorial and Box-Behnken designs. The performance characteristics of the proposed method have been established, showing that the method is efficient to determine amikacin sulphate in the linear range of 9.89-20 mg/L with a detection limit of 2.97 mg/L. It has been successfully applied to the amikacin sulphate determination in pharmaceutical formulations.

Chemiluminescent assay for detection of viable microorganisms

The redox reaction between quinone and viable microorganisms produces active oxygen species. In this study, the production rates of active oxygen species were determined by a luminol chemiluminescent assay, and the luminescence intensity was found to be proportional to the viable cell number. The high sensitivity of the luminol chemiluminescent assay was achieved with Mo-ethylenediaminetetraacetate complex and menadione or coenzyme Q1. The detectable cell densities of bacteria and yeasts were found to be approximately several thousand colony-forming units (CFU/ml) when assays were performed with a 96-well microplate luminometer. The chemiluminescent assay requires 10 min for incubation of quinone and microorganisms and 2s for photon counting. Single Escherichia coli was detected after 4h of cultivation and centrifugation (5 min x 2). This simple chemiluminescent assay is expected to be useful for the rapid detection of viable bacteria and yeast.

Automated enzymatic assays in a renewable fashion using the multisyringe flow injection scheme with soluble enzymes

In this paper, a novel flowing stream scheme based upon the multisyringe flow injection (MSFI) technique is presented as a powerful tool to perform automated enzymatic assays. The exploitation of enzymes in homogeneous phase circumvents typical drawbacks associated with the commonly used packed-bead or open tubular permanent columns, namely, malfunctions of the reactor, carryover effects, flow resistance, loss of binding sites, large reagent consumption, and use of harmful organic solvents during immobilization procedures. The proposed MSFI system is able to handle minute volumes of soluble enzymes and accommodate reactions with divergent kinetic and pH demands, as demonstrated via the indirect chemiluminescence determination of trace levels of glucose. The procedure is based on the on-line glucose oxidase-catalyzed oxidation of beta-glucose in homogeneous phase to beta-glucono-delta-lactone and hydrogen peroxide. Subsequently, the generated oxidant merges downstream with an alkaline slug of 3-aminopthalhydrazide and a metal-catalyst zone (viz., Co(II)) at a total flow rate as high as 72 mL/min aiming to warrant maximum light collection from the fast CL reaction. Under optimum conditions for both sequentially occurring reactions, a glucose concentration as low as 90 microg/L may be easily detected at a 1000-fold photomultiplier gain. A second-order polynomial regression equation of light emission versus substrate concentration is found over the range 90 microg/L-2.7 mg/L glucose, although a maximum concentration of 180 mg/L may be determined by suitable gain selection without requiring manifold reconfiguration. An injection throughput of 20 h(-1), a repeatability better than 2.5% at the 1 mg/L level, and a 3sigma detection limit of 72 microg/L are the analytical features of the designed analyzer. The proposed approach was applied to the analysis of ultralow glucose content soft drinks as well as fruit juices suitable for diabetic consumers. The accuracy was assessed using the spectrophotometric batch glucose-Trinder method as an external reference methodology for the determination of the target species in parenteral solutions.

Flow injection determination of isoniazid using N-bromosuccinimide- and N-chlorosuccinimide-luminol chemiluminescence systems

A chemiluminescent method for the determination of isoniazid is described. Method is based on the chemiluminescence (CL) generated during the oxidation of luminol by N-bromosuccinimide (NBS) and N-chlorosuccinimide (NCS) in alkaline medium. It was found that the isoniazid could greatly enhance this CL intensity when present in the luminol solution. Based on this observation, a new flow-injection CL method for the determination of isoniazid is proposed in this paper. The detection limits were 4 and 3 ng ml(-1) isoniazid for the NBS- and NCS-luminol CL systems, respectively. The relative CL intensity was linear with the isoniazid concentration in the range of 8-600 and 600-5000 ng ml(-1) for the NBS-luminol CL system, and 6-200 and 200-2000 ng ml(-1) for the NCS-luminol CL system. The results obtained for the assay of pharmaceutical preparations compared well with those obtained by the official method and demonstrated good accuracy and precision.

Development of novel high-sensitivity chemiluminescence assay for luminol using thiourea derivatives

We have screened about 100 thiourea derivatives in order to develop a sensitive chemiluminescence detection for luminol derivatives. Among these derivatives, we found a new compound, 2-(3-methylthioureido) thiazole, that could be used to measure luminol in the presence of hydrogen peroxide (H(2)O(2)). The detection limits of luminol and N-(4-aminobutyl)-N-ethylisoluminol (ABEI) were 10 fmol and 100 fmol, respectively. The mechanism of proposed chemiluminescence reaction was studied by electron spin resonance (ESR) with and without superoxide dismutase (SOD) and the addition of ethanol. The results showed that 2-(3-methylthioureido) thiazole has the ability to generate hydroxyl radical from H(2)O(2), and produces intense chemiluminescence in the presence of luminol. The proposed novel chemiluminescence reaction for luminol and luminol derivatives was applied to a high performance liquid chromatography (HPLC) assay for amino compounds.

Analysis of prostaglandin G/H synthase-2 inhibition using peroxidase-induced luminol luminescence

The inducible form of the heme-protein prostaglandin G/H synthase (PGHS-2 or COX-2) has been established as a pivotal enzyme in the cascade of events leading to inflammation, hyperalgesia, and pyresis and represents a major therapeutic target in inflammatory disease. Accordingly, we have exploited the heme-catalyzed hydroperoxidase activity of recombinant hCOX-2 to generate luminescence in the presence of luminol, or a cyclic naphthalene hydrazide, and the substrate arachidonic acid. Arachidonate-induced luminescence was shown to be an index of real-time catalytic activity and demonstrated the turnover inactivation of the enzyme. Luminol luminescence was proportional to hCOX-2 concentration and gave accurate Km determinations for arachidonate. Inhibition of hCOX-2 activity, measured by luminescence, by a variety of selective (for COX-2) and nonselective inhibitors showed rank orders of potency similar to those observed with other in vitro and whole cell methods using the recombinant protein. The sensitivity of the luminescence assay also allowed determination of inhibitor potency at substrate concentrations below Km, distinguishing competitive inhibitors such as ibuprofen from time-dependent inhibitors such as DuP-697. Finally the use of higher quantum-yielding luminol analogues allowed measurement of cyclooxygenase activity at extremely low substrate and protein concentrations, enabling a variety of novel assay formats.

Early detection of peritonitis in continuous ambulatory peritoneal dialysis patients by use of chemiluminescence: evaluation of diagnostic accuracy by receiver-operating characteristic curve analysis

Continuous ambulatory peritoneal dialysis (CAPD) is now a widely accepted treatment for end-stage renal disease. However, the high incidence of peritonitis is a major complication of CAPD. Polymorphonuclear leukocytes (PMNs) play a major role in antimicrobial response of the host. During phagocytosis, the PMNs undergo a striking increase in oxidative metabolism, known as the respiratory burst, and emit light as chemiluminescence (CL). CL is thus a sensitive measure of PMN oxidative potential and correlates well with antimicrobial activity. In view of the observation of increased susceptibility to infection in CAPD patients, we have studied lucigenin- and luminol-enhanced CL in peritoneal fluids of these patients and assessed the diagnostic accuracy of these tests by ROC curve analysis. ROC curves showed diagnostic accuracies for both tests that were superior to counts of PMNs in the dialysis fluid (P <0.001). At selected cutoff values of 150000 cpm/vial for lucigenin CL and 600000 cpm/vial for luminol CL, sensitivities were 100%. Specificities for lucigenin and luminol CL were 89% and 80%, respectively. Our results suggest that CL measurements can be used as an early marker for the presence of infection in CAPD patients.

Luminol-chemiluminescence in free peritoneal cells in hemorrhagic shock in rats treated with PAF-receptor-antagonist BN 52021

The activity of rat peritoneal cells were assessed by the phorbol mirystinian acetate (PMA)-induced luminol chemiluminescence (LCL). Results in control groups (0 - no manipulation, and I - carotid artery cannulation) were compared with those in the untreated hemorrhagic shock (group II), in the shock treated with the standard polyelectrolyte solution (PES) (group III), and in shock treated with PAF receptor-antagonist BN 52021 + PES (group IV). The maximal and the most rapid LCL was observed in the group treated with BN 52021 (group IV), while chemiluminescent response in the the untreated shock (group II) and in shock treated with PES was minimally expressed and late. The findings indicate for a rapid activation of peritoneal cells during ca 1 hour of hemorrhagic shock. This leads to exhausting their ability to the superoxide anion generation 15 minutes later. Peritoneal cells obtained from the group treated with the BN 52021 revealed a preserved ability to the respiratory burst. It can be concluded that BN 52021 effectively inhibits activation of the PC during hemorrhagic shock.

Synthesis of diazoluminomelanin (DALM) in HL-60 cells for possible use as a cellular-level microwave dosimeter

Chemical and bacterial synthesis of a thermochemiluminescent polymer known as diazoluminomelanin (DALM) has been previously reported. This paper focuses on the intracellular synthesis of aminomelanin (AM) in mammalian cell lines and subsequent DALM synthesis from this core molecule. B16 melanoma cells, HL-60 myeloid leukemia cells, and RAW 264.7 macrophages show AM and DALM production. Macroscopic image analysis of HL-60 cell lysates containing DALM using the Quantitative Luminescence Imaging System (QLIS) showed increased chemiluminescence (CL) with increased microwave power input and increased temperature. This work represents a first step toward the goal of microscopic radiofrequency dosimetry of individual DALM-loaded cells using image analysis.

Phagocytosis associated chemiluminescence of hemocytes in Mytilus edulis (Bivalvia)

The respiratory burst associated with phagocytosis by Mytilus edulis hemocytes was investigated by measurement of luminol-dependent chemiluminescence (LDCL). After experimental parameters (number of cells, quantity of stimulus) were determined, the biochemical mechanisms involved in the chemiluminescent process were investigated using inhibitors of oxygen radicals and enzymes. In particular, catechol-like phenols suggested the involvement of NADPH-oxidase and peroxidase in oxidative metabolism of mussel hemocytes. The variability of LDCL response observed among individuals and separated hemocyte subpopulations strongly suggests a variable immunocapacity depending on hemogram composition. Using a specific monoclonal antibody to discriminate different hemocyte types, the eosinophilic granulocytes appeared to exhibit the highest LDCL activity.

A chemiluminescent assay for measuring avermectin binding sites

Avermectins are potent, broad spectrum anthelmintics. We describe the synthesis of a biologically active chemiluminescent compound, 22,23-dihydroavermectin B1a, 4"-[4-[[4-[ethyl(1,2,3,4-tetrahydro-1,4-dioxo-6- phthalazinyl)amino]butyl]amino]-4-oxobutanoate] (ivermectin-luminol). This compound retains its anthelmintic properties and provides an extremely sensitive nonradioactive probe to study avermectin binding sites.

A comparison of non-radioisotopic hybridization assay methods using fluorescent, chemiluminescent and enzyme labeled synthetic oligodeoxyribonucleotide probes

N4-[N-(6-trifluoroacetylamidocaproyl)-2-aminoethyl]-5'-O-dimethoxy trityl -5-methyl-2'-deoxycytidine-3'-N,N-diisopropyl-methylphosphoramidite++ + has been synthesized. This N4-alkylamino deoxycytidine derivative has been incorporated into oligonucleotide probes during chemical DNA synthesis. Subsequent to deprotection and purification, fluorescent (fluorescein, Texas Red and rhodamine), chemiluminescent (isoluminol), and enzyme (horseradish peroxidase, alkaline phosphatase) labels have been specifically incorporated. Detection limits of the labels and labeled probes were assessed. Also, the detection limits and nonspecific binding of the labeled probes in sandwich hybridization assays were determined. The enzyme modified oligonucleotides were found to be significantly better labeling materials than the fluorescent or chemiluminescent derivatives, providing sensitivities comparable to 32P-labeled probes.

[Determination of the phagocytosis of granulocytes by the measurement of chemiluminescence]

During two successive years the phagocytic capacity of the granulocytes of 800 children from areas with environmental pollution and with clean air was examined and compared. To this end, the luminol chemiluminescence during phagocytosis of opsonized zymosan was measured in whole blood. In all areas the phagocytic activity of the granulocytes of boys was higher than that of girls. In area with environmental pollution it was higher than in clean-air areas. The cells disposition towards phagocytosis was lower in clean-air areas than in areas with an environmental burden. Boys showed a more rapid increase in phagocytosis than girls. Between both years of examination distinct differences were observed in the level of chemiluminescence. The phagocytic defense systems of children who grew up in areas rated as having an environmental burden, showed a distinct change in activity as opposed to that of children from so-called clean-air areas. It could be proved that the phagocytic defense system of clinically healthy children reacts to environmental irritants with a change of its activity state.

Dependence on antibody for induction of chemiluminescence in polymorphonuclear leukocytes by herpes simplex virus

The induction of luminol-dependent chemiluminescence in rabbit polymorphonuclear leukocytes (PMN) by a stromal keratitis causing strain (RE) of herpes simplex virus type 1 (HSV-1) was examined. Virus alone and virus infected rabbit corneal cells were unable to stimulate chemiluminescence. However, when the virus or virus infected cells were incubated in the presence of HSV-1 specific immune serum or purified IgG, a gradual chemiluminescent response was observed. Virus and virus infected cells incubated with normal rabbit serum or IgG produced little or no activity. No impairment of chemiluminescent response was observed in experiments in which rabbit PMN were exposed to HSV prior to the addition of opsonized zymosan or HSV-antibody complexes. Results suggest PMN exert antiviral activity in the presence of specific antibody and may be important factors in the inflammatory process resulting from ocular HSV infection.

Synthesis and evaluation of luminescent tracers and hapten-protein conjugates for use in luminescence immunoassays with immobilised antibodies and antigens. A critical study of macro solid phases for use in immunoassay systems, Part II

This article describes the synthesis of labels and hapten-protein conjugates for use in bio- and chemiluminescent immunoassay systems, together with the problems encountered. The effects of maleimide upon acetate-, adenylate- and pyruvate kinase activity have been studied, as well as upon the luciferin-luciferase monitoring system. Maleimide inhibited both acetate and adenylate kinase but showed no inhibition of pyruvate kinase and the monitoring reagent. Four heterobifunctional reagents were tested for their capability in forming pyruvate kinase-donkey-anti-rabbit IgG conjugates which retained enzyme and antibody activity. The best results were obtained with succinimidyl-4-(N-maleimidomethyl)-cyclohexane-1-carboxylate and succinimidyl-6-(p-maleimidophenyl)-hexanoate. The relationship between the amounts of succinimidyl-4-(N-maleimidomethyl)-cyclohexane-1-carboxylate and IgG was studied with respect to enzymic activity of the conjugate. The Michaelis-Menten constants for both conjugated and non-conjugated pyruvate kinase were calculated and compared. It was found that the maximal velocity (Vmax) of the conjugated enzyme was lower than that of the non-conjugated enzyme although the "apparent" Km value was the same for both conjugated and non-conjugated pyruvate kinase. The pyruvate kinase-anti rabbit IgG conjugate was tested for its ability to bind to rabbit-IgG coated polystyrene balls. In addition to bioluminescent labels, the synthesis of chemiluminescent markers was undertaken and optimised. The three substances used for labelling were diazoluminol, diazoisoluminol and N-(4-aminobutyl)-N-ethylisoluminol hemisuccinamide the latter being used as an N-hydroxysuccinamide "active" ester. The ratio of label to IgG was studied for diazoluminol and N-(4-aminobutyl)-N-ethylisoluminol hemisuccinamide active ester after it had been discovered that diazoisoluminol was not suitable for coupling to antibodies. The optimal molar ratios label: IgG were for diazoluminol 40:1 and for N-(4-aminobutyl)-N-ethylisoluminol hemisuccinamide active ester 60:1. Increasing the substitution rate led to a lessening of the dynamic range, shown by an increase in the ratio between unspecific binding (noise) to maximal binding (signal) in an assay. The synthesis of hapten-protein conjugates for covalent coupling to polystyrene balls was undertaken as this formed part of the preparation for the assays described in Part III. The optimal production of gentamicin-bovine serum albumin and thyroxine-transferrin conjugates has been described in detail.