Iodide Probe Research Articles

LiaSR two-component system modulates the oxidative stress response in Streptococcusmutans

Many commensal bacteria of the human oral microbiome can produce reactive oxygen species (ROS). ROS will inhibit the colonization of Streptococcusmutans (S.mutans), a major pathogenic bacteria in dental caries. The LiaSR two-component system in S.mutans can sense and respond to environmental oxidative stress. However, the molecular details of the LiaSR two-component system and oxidative stress response have been unclear. In this study, we aimed to elucidate the underlying mechanisms of the LiaSR two-component system and the mediated oxidative stress response in S.mutans. We performed the H2O2 killing assay, Confocal laser scanning microscopy, and 2,7-Dichlorofluoresce diacetate staining assay to evaluate the sensitivity of S.mutans to H2O2. The propidium iodide probe and TUNEL kit were used to detect the membrane permeability and DNA fragmentation. Quantitative real-time PCR was conducted to analyze the expression level of underlying regulated genes. The liaS and liaR deficient mutants were particularly sensitive to H2O2 compared to their wild strain S.mutans 593, which was previously isolated from a caries-active patient. The intracellular levels of ROS and membrane permeability increased in the mutants. The TUNEL assay showed that the rate of DNA fragmentation in the liaR mutant was higher compared to the wild strain and liaS mutant. Relative expression of the spxA2 gene in the mutants was lower than in the wild strain. The dpr and dinB genes were downregulated in the liaR mutant. These results indicated that the LiaSR two-component system mediated influence on spxA2 expression in S.mutans and contributed to membrane homeostasis, which was involved in the oxidative response process. S.mutans could also elevate the dpr and the dinB genes, which depend on the liaR component in the LiaSR system, may help reduce the DNA damage caused by ROS. This study provides valuable insights into the mechanisms of the LiaSR two-component system in the oxidative stress response of S.mutans.

Gum-based nanocapsules comprising naphthoquinones enhance the apoptotic and trypanocidal activity against Trypanosoma evansi

Nanoencapsulation is a promising approach to enhance the therapeutic potential of a drug. Herein, three selected naphthoquinone (NTQ) derivatives, based on the IC50 value against Trypanosoma evansi, were encapsulated using gum damar as biocompatible and biodegradable natural gum via nanoprecipitation method. Nanoformulation of NTQs (NNTQs) was less than 150 nm in size, was found to be stable and released the drug in a sustained manner. All the three NNTQs exhibited significant antitrypanosomal effect and morphological changes at approximately two to three times lesser drug concentrations. The nanoformulations exhibited enhanced production of reactive oxygen species (ROS) in the axenic culture of T. evansi and less cytotoxic effect on horse peripheral blood mononuclear cells relative to pure NTQs. As evidenced by flow cytometry, the NNTQs showed dose-dependent and time-dependent increased transition of live cells (AV-PI-) to early apoptotic cells (AV+PI−), late apoptotic cells (AV−PI+), and necrotic cells (AV+PI+) using annexin V/propidium iodide probe analysis. The results concluded that NNTQs induced more ROS, apoptosis and necrotic effects that exhibited more inhibitory effect on the growth of T. evansi with respect to respective NTQ by themselves.

Preparation and Antitumor Activity of Betulin Dipropionate and its Composites

Betulin dipropionate is a natural compound with high cytotoxicity toward many cancer cells. The one-step synthesis directly from the birch bark without a separate betulin isolation stage was developed to obtain betulin dipropionate. Due to its composition, betulin dipropionate is a promising drug for treating a wide range of diseases. However, the poor water solubility of this compound has limited its applications. We prepared the composites of betulin dipropionate using two methods: ball milling of the mixtures of betulin dipropionate with synthetic and natural polymers, such as polyvinylpyrrolidone polyethylene glycol, fumed silica, arabinogalactan, and preparation of thin films with arabinogalactan by evaporating the aqueous solutions. These composites showed higher water solubility and improved antitumor properties against ascites carcinoma cells and human lung adenocarcinoma cells compared with the initial substance. Furthermore, the cell viability studies based on Annexin V and Propidium iodide probes confirmed the high proapoptotic effect of betulin dipropionate against cancer cells.

Next-generation multiparameter flow cytometry assay improves the assessment of oxidative stress in probiotics

Stability of probiotic products’ potency throughout shelf life is essential to ensure systematic delivery of the dosages required to provide clinically-proven health benefits. Due to the oxygen sensitivity of gut-derived microorganisms, methods for the rapid and accurate monitoring of oxidative stress in probiotics are greatly needed as they can be instrumental to both bioprocess optimization and quality control. This study introduces a next-generation flow cytometry method multiplexing the CellROX® Green and Propidium Iodide probes for the simultaneous measurement of free total reactive oxygen species (ROS) and membrane integrity, respectively. The multiparameter method was compared to the single-parameter assays, measuring either ROS or membrane integrity, for the ability to evaluate the fitness of Lactobacillus rhamnosus GG (LGG) after freeze drying, spray drying and H2O2-mediated oxidative stress. Each stand-alone assay detected only three cell populations, showing either differential membrane integrity (Syto 24+/PI-, Syto 24+/PI+, Syto 24-/PI+) or ROS levels (ROS-, low-ROS, high-ROS), and no correlation could be drawn between these groups. Conversely, the multiparameter method detected up to five physiologically distinct cell populations and allowed the integrated assessment of their membrane integrity and oxidative stress. It also revealed a much larger fitness heterogeneity in LGG as each group of low-ROS and high-ROS cells was found to be formed by a healthier population with an intact membrane (L-ROS/PI-, H-ROS/PI-) and a population with damaged membrane (L-ROS/PI+, H-ROS/PI+). As the CRG probe only detects free unreacted ROS, these populations are suggested to reflect the dynamic lifecycle of ROS formation, accumulation and reactive depletion leading to oxidative damage of macromolecules and consequent cell death. With the stand-alone CRG assay being unable to detect ROS lifecycle, the multiparameter method here presented delivers a superior profiling of the heterogeneity generated by oxidative stress in bacteria and enables a more correct interpretation of CRG fluorescence data. We provide recent examples from literature where the use of a single-parameter fluorescence approach may have led to misinterpret oxidative stress data and eventually draw erroneous conclusions.

A dendrimer consisting of a pyrene core and a 9-phenylcarbazole periphery as a multi-functional fluorescent probe for iodide, iron(III) and mercury(II).

A dendrimer (termed G2) containing pyrene as the core and 9-phenylcarbazole (PCZ) on the periphery is shown to be a multi-functional fluorescent probe for iodide, iron(III) and mercury(II). It serves as the fluorometric/colorimetric dual-channel probe for these ions. As a fluorometric probe, the fluorescence of G2 is quenched both by iodide and iron(III). After that, the fluorescence of G2 which has been added iodide will recover when added mercury(II); as a colorimetric probe, the color of G2 solution can turn to yellow only by iodide which will change from yellow to colorless again when adding mercury(II). The color change is sensitive and observed visually at 0.1mM for iodide. G2 also is an electroactive precursor for preparation of fluorescent films via electropolymerization. The resulting films can be used as the fluorescent films to sense the ions. This is attributed to the presence of a large specific surface, highly cross-linked microstructures and enhanced π conjugation. The electropolymerized film has blue fluorescence with excitation/emission maxima at 365/460nm. The limits of detection (LOD) of G2 for iodide, iron(III) and mercury(II) were calculated to be 9.3, 37.1 and 22.0nM in solution and 5.1, 12.0 and 6.1nM in films, respectively. The linear range is from 2 to 10μM for G2 electropolymerized films. The detection range is from 2 to 400μM for iron(III) and mercury(II). The detection range is from 2 to 130μM for iodide. For a third application, G2 displays compelling sensing performance in environmental systems and in living roundworms. Graphical abstractAs schematic presentation, after adding iodide, the fluorescence of G2 is quenched and the color changes to yellow. When adding Hg2+ to G2-iodide, the fluorescence and color of G2 recover. Iron(III) can also quench G2, but the color doesnot change.

Preliminary study on conjugation of formononetin with multiwalled carbon nanotubes for inducing apoptosis via ROS production in HeLa cells.

BackgroundThe present work was conducted to prepare and evaluate multiwalled carbon nanotube–formononetin (MWCNT-FMN) composite for sustained delivery and inducing apop-tosis via reactive oxygen species (ROS) production in HeLa cells.MethodsThe composite was prepared by solution mixing with short carboxylic group-functionalized multiwalled carbon nanotubes (MWCNT-COOH). Then the composite was characterized by laser particle size analysis, Fourier transform infrared spectrometry, X-ray diffractometry, differential scanning calorimetry, and scanning electron microscopy. Drug release rates in vitro were determined by dialysis method. The in vitro cytotoxicity study was performed using water soluble tetrazolium assay. The cellular apoptosis assay, ROS, and mitochondrial membrane potential (MMP) of HeLa cells were investigated by acridine orange and ethidium bromide double dye, 2′,7′-dichlorodihydrofluorescein diacetate, and 5,5′,6,6′-tetrachloro-1,1′,3,3′-tetraethyl-imidacarbocyanine iodide probe, respectively.ResultsThe entrapment efficiency was 28.77%±0.15%, and the loading capacity was 12.05%±0.20%. The release of MWCNT-FMN was sustained, and the cumulative release rate of formononetin (FMN) from MWCNT-COOH was higher at pH 7.4 than at pH 5.3. The in vitro cytotoxicity assay demonstrated that FMN, MWCNT-COOH, and MWCNT-FMN had no significant effects on the proliferation and viability of mouse fibroblast 3T3 cells over 48 hours, while the cell growth inhibition of the three samples showed concentration-dependent for HeLa cells. Biological assay suggested FMN and MWCNT-FMN could induce apoptosis in HeLa cells, meanwhile the cells exhibited stronger ROS signal and more depolarized MMP than that of the control group.ConclusionThese results preliminarily demonstrated that MWCNT-FMN exerted anticancer efficacy through cellular apoptosis induced by ROS-mediated mitochondrial dysfunctions in HeLa cells.

Early Activation of Apoptosis and Caspase-independent Cell Death Plays an Important Role in Mediating the Cytotoxic and Genotoxic Effects of WP 631 in Ovarian Cancer Cells.

The purpose of this study was to provide a detailed explanation of the mechanism of bisanthracycline,?WP 631 in comparison to doxorubicin (DOX), a first generation anthracycline, currently the most widely used pharmaceutical in clinical oncology. Experiments were performed in SKOV-3 ovarian cancer cells which are otherwise resistant to standard drugs such as cis-platinum and adriamycin. As attention was focused on the ability of WP 631 to induce apoptosis, this was examined using a double staining method with Annexin V and propidium iodide probes, with measurement of the level of intracellular calcium ions and cytosolic cytochrome c. The western blotting technique was performed to confirm PARP cleavage. We also investigated the involvement of caspase activation and DNA degradation (comet assay and immunocytochemical detection of phosphorylated H2AX histones) in the development of apoptotic events. WP 631 demonstrated significantly higher effectiveness as a pro-apoptotic drug than DOX. This was evident in the higher levels of markers of apoptosis, such as the externalization of phosphatidylserine and the elevated level of cytochrome c. An extension of incubation time led to an increase in intracellular calcium levels after treatment with DOX. Lower changes in the calcium content were associated with the influence of WP 631. DOX led to the activation of all tested caspases, 8, 9 and 3, whereas WP 631 only induced an increase in caspase 8 activity after 24h of treatment and consequently led to the cleavage of PARP. The lack of active caspase 3 had no outcome on the single and double-stranded DNA breaks. The obtained results show that WP 631 was considerably more genotoxic towards the investigated cell line than DOX. This effect was especially visible after longer times of incubation. The above detailed studies indicate that WP 631 generates early apoptosis and cell death independent of caspase-3, detected at relatively late time points. The observed differences in the mechanisms of the action of WP631 and DOX suggest that this bisanthracycline can be an effective alternative in ovarian cancer treatment.

A mercuric ensemble based on a cycloruthenated complex as a visual probe for iodide in aqueous solution

A new water-soluble cycloruthenated complex Ru(bthiq)(dcbpy)2+ (1, Hbthiq=1-(2-benzo[b]thiophenyl)isoquinoline, dcbpy=4,4′-dicarboxylate-2,2′-bipyridine) was designed and synthesized to form its mercuric ensemble (1-Hg2+) to achieve visual detection of iodide anions. The binding constant of 1-Hg2+ is calculated to be 2.40×104M−1, which is lower than that of HgI2. Therefore, the addition of I− to the aqueous solution of 1-Hg2+lead to significant color changes from yellow to deep-red by the release of 1. The results showed that iodide anions could be easily detected by the naked eyes. The detection limit of iodide anion is calculated as 0.77μM. In addition, an easily-prepared test strip of 1-Hg2+ was obtained successfully to detect iodide anions.

New composites of betulin esters with arabinogalactan as highly potent anti-cancer agents

Betulin and its esters are the natural compounds with high in vitro cytotoxicity toward many cancer cells. However, the poor water solubility of these compounds has limited their applications. We prepared new composites of betulin esters using two methods, namely ball-milling of the mixtures of betulin esters with arabinogalactan and preparation of thin films of these mixtures by evaporating the aqueous solutions. These composites revealed higher water solubility as compared with the initial substances without losing the structural integrity and functionality. As a result, the new composites have shown much higher inhibitory effects against different cancer cell lines such as Ehrlich ascites carcinoma cells and lung carcinoma cells (A549) in comparison with the initial substances. The cell viability studies based on Annexin V and Propidium iodide probes have confirmed the high proapoptotic effect of betulin ester derivatives against cancer cells.

Investigation of antimalarial activity, cytotoxicity and action mechanism of piperazine derivatives of betulinic acid.

To semisynthesise piperazine derivatives of betulinic acid to evaluate antimalarial activity, cytotoxicity and action mechanism. The new derivatives were evaluated against the CQ-sensitive Plasmodium falciparum 3D7 strain by flow cytometry (FC) using YOYO-1 as stain. Cytotoxicity of 4a and 4b was performed with HEK293T cells for 24 and 48 h by MTT assay. The capability of compound 4a to modulate Ca(2+) in the trophozoite stage was investigated. The trophozoites were stained with Fluo4-AM and analysed by spectrofluorimetry. Effect on mitochondrial membrane potential (ΔΨm) was tested for 4a by FC with DiOC6 (3) as stain. For β-haematin assay, 4a was incubated for 24 h with reagents such as haemin, and the fluorescence was measured by FlexStation at an absorbance of 405 nm. Antimalarial activity of 4a and 4b was IC50 = 1 and 4 μm, respectively. Compound 4a displayed cytotoxicity with IC50 = 69 and 29 μm for 24 and 48 h, respectively, and 4b was not cytotoxic at the tested concentrations. Addition of 4a leads to an increase in cytosolic Ca(2+) . We have measured ΔΨm after treating parasites with the compound. Data on Figure 4a show that mitochondria were not affected. The action mechanism for 4a, inhibition of β-haematin formation (17%), was lower than CQ treatment (83%; IC50 = 3 mm). Compound 4a showed excellent antimalarial activity, and its action mechanism is involved in Ca(2+) pathway(s).

Galacto-oligosaccharides and lactulose as protectants against desiccation of Lactobacillus delbrueckii subsp. bulcaricus.

Lactobacillus delbrueckii subsp. bulgaricus CIDCA 333 was dehydrated on desiccators containing silica gel in the presence of 20% w/w of two types of galacto-oligosaccharides (GOS Biotempo and GOS Cup Oligo H-70®) and lactulose, until no changes in water desorption were detected. After rehydration, bacterial growth was monitored at 37°C by determining: (a) the absorbance at 600 nm and (b) the near infrared spectra (NIR). Principal component analysis (PCA) was then performed on the NIR spectra of samples dehydrated in all conditions. A multiparametric flow cytometry assay was carried out using carboxyfluorescein diacetate and propidium iodide probes to determine the relative composition of damaged, viable, and dead bacteria throughout the growth kinetics. The absorbance at 600 nm and the position of the second derivative band at ∼1370 nm were plotted against the time of incubation. The efficiency of the protectants was GOS Biotempo > GOS Cup Oligo H-70® > lactulose. The better protectant capacity of GOS Biotempo was explained on the basis of the lower contribution of damaged cells immediately after rehydration (t = 0). PCA showed three groups along PC1, corresponding to the lag, exponential and stationary phases of growth, which explained 99% of the total variance. Along PC2, two groups were observed, corresponding to damaged or viable cells. The results obtained support the use of NIR to monitor the recovery of desiccated microorganisms in real time and without the need of chemical reagents. The use of GOS and lactulose as protectants in dehydration/rehydration processes was also supported.

Carbazole and triazole-containing conjugated polymer as a visual and fluorometric probe for iodide and mercury

A new conjugated polymer containing carbazole and triazole moieties (P1) was successfully synthesized by Suzuki coupling reaction. The UV–vis and fluorescence spectra of the P1 showed significant changes via addition of I− and Hg2+. A colorless P1 solution turned yellow in the presence of iodide salts, which subsequently became colorless again on the addition of Hg2+ salts that could be easily detected visually by the bare eyes. P1 allowed a highly sensitive determination of iodide via significant FL intensity quenching, and fluorescence recovery was observed following the addition of Hg2+. The Stern–Volmer constant (Ksv) value obtained for the detection of iodide was 2.25×107M−1, confirming very high sensitivity of P1 for iodide salts. The detection of both iodide and mercury was also possible in solid state by a P1-based test strip, which showed the capability to detect and respond to both iodide and mercury salts. The results indicated that P1 can act as a dual-channel, high selective, immediacy and sensitive optical probe for I− and Hg2+.

Fluorescence sensing of iodide and bromide in aqueous solution: anion ligand exchanging and metal ion removing

A new rhodamine-based fluorescent probe RSP was facilely synthesized. Interestingly, the RSP-Hg-ClO4 ensemble can serve as a selective fluorescent probe for iodide and bromide based on metal ion removal and anion ligand exchanging, which is a novel rhodamine-based fluorescence sensing mechanism. Moreover, RSP can recognise Hg2+ selectively in 99% aqueous solution.

A simple coumarin-based colorimetric and ratiometric chemosensor for acetate and a selective fluorescence turn-on probe for iodide

A novel colorimetric and ratiometric anion chemosensor bearing phenylhydrazone- coumarin moieties as recognition sites was rationally designed and synthesized. Upon addition of a series of anions to receptor R1 in 1:1 CH 3CN/H 2O, only the appearance of the solution of receptor R1 with acetate showed a color change from pale yellow to purple (bathochromic shift from 411 to 573 nm) which can be detected by the naked eye at parts per million. The probe R1 developed herein represents the rational design of a fluorescence turn-on probe for iodide, which is a notorious fluorescence quencher due to the heavy atom effect. The probe developed herein represents the fluorescence amplified probe for iodide.

Comparison of Dosimetry and Gamma Camera Methods for Evaluation of Biodistribution Prior to Administration of the Therapeutic Dose of Tositumomab and Iodine I 131 Tositumomab (Bexxar Therapeutic Regimen)

AbstractAbstract 4916 Introduction:The Bexxar® Therapeutic Regimen for relapsed/refractory follicular lymphoma (FL) is administered in 2 steps: a dosimetric dose and a therapeutic dose. Radioactive counts, obtained from sequential gamma camera scans of the whole body at several time points after the dosimetric dose, determine the patient (pt)-specific clearance (total body residence time, TBRT) and, along with pt body size, allow determination of the prescribed activity (PA) of the therapeutic dose. Pts do not receive the therapeutic dose if TBRT is outside 50 to 150 hrs and/or gamma camera images show altered biodistribution. TBRT is used to calculate the mCi of I-131 (PA) required to deliver the appropriate therapeutic dose of 65 or 75 cGy to the total body, depending on platelet count. Our aims were 1) to evaluate an alternative, inexpensive sodium iodide probe (probe) detector-based method of measuring radioactive counts for determination of TBRT and 2) to evaluate the clinical benefit of visually assessing gamma camera images for altered biodistribution. Methods:We retrospectively compared probe and gamma camera methods from a phase II study (RIT-II-001) and evaluated altered biodistribution assessed by gamma camera images from a post-marketing observational study. Forty-one of 47 FL pts enrolled in RIT-II-001 from December 1995 to November 1996 were included in the retrospective analysis of TBRT and PA. Pts received a median of 5 prior chemotherapies (range 2–13). Thirty of 41 (73%) pts had low-grade B-NHL, 90% had stage III or IV disease, 51% had bone marrow involvement, 88% had an International Prognostic Index score ≥ 2, and 16 of 34 (47%) pts had bulky disease >500 g. Dosimetry analysis was performed at 3 time points (Day 0; Day 2, 3, or 4; and Day 6 or 7) after dosimetric dose, as currently required for determining PA. The PAs of the therapeutic dose using TBRTs derived from probe and gamma camera counts were compared. Also, we retrospectively evaluated cases of altered biodistribution in an observational post-marketing study (BEX114606) of 2,649 pts who received a dosimetric dose from June 2003 to February 2010. Dosimetry and gamma camera images were independently reviewed from reported cases of altered biodistribution to evaluate the clinical benefit of visually assessing gamma camera images. Results:The mean TBRTs from the clinical study were 94.5 and 95.0 hrs from the probe and gamma camera methods, respectively, and individual TBRTs were highly correlated (r = 0.98). The mean PAs of the therapeutic dose, derived from probe and gamma camera TBRTs, were 85.8 mCi and 85.3 mCi, respectively. The point estimate for the ratio of the PA was 0.995 and the 90% CI (0.984, 1.006) was well within the typical range of 0.80 to 1.25 for demonstrating bioequivalence. The observational study found that only 5 of 2,649 (0.2%) pts did not receive the therapeutic dose due to suspected altered biodistribution. Dosimetry data and gamma camera images were available for 3 pts. Independent review confirmed that all 3 pts had accurately determined TBRTs, but only 1 pt had confirmed altered biodistribution by visual assessment of gamma camera images and TBRTs. Conclusion:TBRTs derived from probe and gamma camera counts were highly comparable. Thus, the probe and gamma camera methods to determine TBRT and calculate the PA of the therapeutic dose of Bexxar appear equivalent. Altered biodistribution prevented only 5 of 2,649 (0.2%) pts from receiving the therapeutic dose of Bexxar. Only 1 pt (0.04%) was independently confirmed to have altered biodistribution by visual assessment of gamma camera images, consistent with the TBRT. Therefore, visual assessment of gamma camera images added no benefit beyond TBRT in determining whether to administer the therapeutic dose of Bexxar. These data indicate that either sequential probe or gamma camera-based dosimetry is sufficient for determining whether to administer the therapeutic dose, and that visual assessment of gamma camera images does not appear to be necessary to detect the rare instance of an altered biodistribution.Study RIT-II-001 (N=41 pts)ProbeCameraMeanPoint estimate of ratio (90% CI)TBRT (hrs)94.595.0PA (mCi)85.885.30.995 (0.984, 1.006)Study BEX114606No (%) ptsReceived dosimetric dose2649 (100)No therapeutic dose due to suspected altered biodistribution5 (0.2)Images available for review3 (0.11)Abnormal TBRT only2 (0.08)Abnormal TBRT and images1 (0.04)Abnormal images only0 (0) Disclosures:Horner: GlaxoSmithKline: Employment. Off Label Use: The BEXXAR therapeutic regimen (Tositumomab and Iodine I 131 Tositumomab) is indicated for the treatment of patients with CD20 antigen-expressing relapsed or refractory, low grade, follicular, or transformed non-Hodgkin's lymphoma, including patients with Rituximab-refractory non-Hodgkin's lymphoma. Siegel: GlaxoSmithKline: Consultancy. Jewell: GlaxoSmithKline: Employment. Lunger: GE Healthcare: Employment. Young: GlaxoSmithKline: Employment. Wynne: GlaxoSmithKline: Employment. Williams: GlaxoSmithKline: Employment. Lin: GlaxoSmithKline: Employment. Kaminski: GlaxoSmithKline: Patents & Royalties, Research Funding. Wahl: GlaxoSmithKline: Consultancy, Patents & Royalties; Nihon Medi Physics: Consultancy; Spectrum Pharmaceuticals: Consultancy; Naviscan PET systems: Consultancy; Threshold Pharmaceuticals: Equity Ownership. Vleisides: GlaxoSmithKline: Employment.

A fluorescence turn-on probe for iodide based on the redox reaction between cupric and iodide

We have successfully introduced a novel strategy for the rational design of a fluorescence turn-on probe for iodide, which is a notorious fluorescence quencher due to the heavy atom effect. The strategy is based on the redox reaction between Cu 2+ and iodide. The probe exhibited a 20-fold fluorescence enhancement in the presence of 4 equiv. of iodide. The probe developed herein represents the first fluorescence amplified probe for iodide. We believe that it will find interesting use in environment.

Cu(II) complex of a flexible tripodal receptor as a highly selective fluorescent probe for iodide

A Cu(II) complex of a tripodal receptor bearing an anthracene moiety on one pod as a fluorophore was synthesized. The anion recognition behavior of the Cu(II) complex was evaluated in CH 3CN/H 2O (95:5, v/v), resulting in an extremely high selectivity for iodide over other anions such as F −, Cl −, Br −, NO 3 - , CH 3COO −, and H 2 PO 2 - . The Cu(II) complex acts as a selective probe for estimating iodide even in the presence of other anions without any interference.

Loss of cardiolipin in palmitate‐treated GL15 glioblastoma cells favors cytochrome c release from mitochondria leading to apoptosis

Unlike oleate and linoleate, palmitate induced mitochondrial apoptosis in GL15 glioblastoma cells. Decrease in membrane potential in a subpopulation of mitochondria of palmitate-treated cells was revealed using the 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolylcarbocyanine iodide probe. The diminished ability to reduce a tetrazolium salt indicated an impairment of mitochondrial function. Up to 50% cytochrome c (cyt c) was detached from the inner mitochondrial membrane and released outside mitochondria in palmitate-treated cells, whereas no release was detected after oleate and linoleate treatments. Cyt c release into the cytosol was followed by caspase 3 activation. Released cyt c and caspase 3 activity were not affected by neutral and acid sphingomyelinase inhibitors and by the inhibitor of serine palmitoyltransferase cycloserine, indicating that apoptosis was independent of the ceramide pathway, nor the mitochondrial pro-apoptotic AIF or Bcl-2/Bax factors appeared to be involved in the effect. Utilization of palmitate by GL15 cells altered phospholipid composition. Cardiolipin (CL), the lipid involved in cyt c interaction with the inner mitochondrial membrane, was decreased and highly saturated. This produced an imbalance in hydrophilic/hydrophobic interactions underlying the anchorage of cyt c, by weakening the hydrophobic component and facilitating detachment of the protein and activation of downstream processes. The primary role of CL was explored by supplying GL15 with exogenous CL through a fusion process of CL liposomes with cell plasma membrane. Fused CL moved to mitochondria, as detected by nonylacridine orange probe. Enrichment of mitochondrial membranes with CL prior to palmitate treatment of cells caused decreased cyt c release and caspase 3 activity.

Intraoperative localization of colorectal cancers using radiolabelled monoclonal antibodies

Radiation detectors may allow the intraoperative localization of small cancer deposits following administration of radiolabelled tumour-associated antibodies. This technique was evaluated in 16 patients with colorectal tumours (14 cancers, one adenoma, one lipoma) with the 111In-labelled monoclonal antibody (MAb) ICR2 which recognizes the tumour-associated epithelial membrane antigen (EMA). At operation counting was carried out (3 x 20 s per site) using a hand-held radiation probe over the primary lesions and any palpable lymph nodes in the mesocolon. The tumour to normal colon (T/NC) ratio of counts recorded at operation was more than 1.5:1 in eight of the 14 patients with cancer (mean(s.d.), 1.54(0.41):1) and 0.91:1 and 1.06:1 respectively in the two patients with benign tumours. Node to normal colon ratios were higher in lymph nodes containing metastases. The uptake of radiolabelled antibody (T/NC ratio) was higher in EMA-expressing cancers than in those not expressing the target antigen (mean(s.d.), 2.45(0.65):1 versus 1.40(0.20):1, P = 0.019). An abdominal tumour model was also developed. Radioactively filled containers of 0.5-10 ml representing tumour deposits were suspended in a tank of 111In solution representing the background activity found in normal tissues. The ratio of radioactivity in the 'tumour' to that of background varied from 2:1 to 8:1. The 'tumour' was considered to be detectable if the mean counts recorded over the 'tumour' exceeded the mean of counts recorded over background by three standard deviations. At a ratio of 2:1 only 'tumours' greater than 5 ml could be detected with a sodium iodide probe and those over 10 ml could be detected with a cadmium telluride (CdTe) probe. At a ratio of 8:1, 'tumours' of 0.5 ml could be detected with either probe. At all ratios and counting periods the NaI probe was more sensitive than the CdTe.

Preparation of Hydrogenated Surfactant/SC CO2 Micelles and Their Micropolarity Determination

Abstract The influence of CO2-philicity and -phobicity of hydrogenated surfactants on preparation of reverse micelles in SC CO2 have been investigated for the first time. To this end, we used polyethylene glycol mono n-alkyl ether surfactants of different polar head groups and alkyl tails. Micelles prepared were characterized by dissolving 1-ethyl-4-methoxycarbonyl pyridinium iodide probe and recording its charge-transfer band in UV absorption region. From the transition energy of charge transfer band the polarity of the aqueous core of micelles was determined in terms of solvent polarity scale ET (30) values.