Single up-conversion nanocrystal as a local temperature probe of electrically heated silver nanowire.

Luminescence thermometry is a powerful technique for monitoring temperature in a sensitive, remote (through light), and minimally invasive manner. Up to now, many macroscopic and microscopic luminescence temperature probes exploiting different temperature sensing schemes have been investigated, with the majority of the studies using aggregates of nanothermometers. This work presents isolated single up-converting NaYF4:Er3+/Yb3+ nanocrystals as functional temperature indicators operating in a standard confocal microscopy configuration. More specifically, the nanocrystals were used to monitor the temperature of a single silver nanowire, whose temperature was controlled electrically via the Joule process. We demonstrate that individual nanocrystals placed near the nanowire can precisely determine the temperature distribution in its surroundings. These results, which combine nanoscopic heat generation with temperature readout using isolated nanocrystals, represent an essential step for the application of isolated single nanoprobes for luminescence thermometry at the nanoscale.

Microwave-assisted synthesis and characterization of novel chitosan-based biomaterials for pelvic organ prolapse treatment.

Pelvic organ disorders affect up to one in four women in the United States. The prevalence of pelvic organ prolapse (POP) is increasing with each year, particularly in the setting of prolonged life expectancy and an aging population. Current treatment approaches, including polypropylene monofilaments are associated with numerous painful and worrisome side-effects. Therefore, scientists are looking for new solutions. A promising alternative to the current treatment is tissue engineering, which can be utilized to re-create support to the vagina and pelvic organs. Tissue engineering requires the use of three-dimensional scaffolds, derived from biocompatible materials. Chitosan is a natural polymer, obtained from shellfish exoskeletons. It is known for its biodegradability, lack of cytotoxicity and non-pyrogenicity. Due to the presence of free hydroxyl and amino groups, it may undergo various modifications. In this paper, we describe a new type of chitosan-based biomaterials, which can be used as a new alternative scaffold that may provide support to prolapse organs. The chitosan scaffold was obtained under microwave radiation using multifunctional amino and organic acids. We discuss the scaffold's characteristics, with an emphasis on its chemical structure and morphology. Fourier transform infrared spectroscopy (FT-IR) analysis confirmed cross-linking processes with preservation of free amino groups. Moreover, mechanical durability, the stability and swelling ability of the scaffolds in a simulated body fluid were investigated. All of the prepared scaffolds demonstrated very good antioxidant activity and biodegradability. Importantly, the biocompatibility of chitosan scaffolds was examined on human vaginal VK2/E6E7 cell line. No evidence of toxicity was documented, and the cells maintained their presence on the studied materials. These results allude to the lack of toxicity of the scaffolds, and indicate that chitosan-based scaffold should be further investigated in in vivo studies as they may be a promising alternative treatment to pelvic organ prolapse.

Analysis of leucocyte antibodies, cytokines, lysophospholipids and cell microparticles in blood components implicated in post-transfusion reactions with dyspnoea.

BACKGROUND AND OBJECTIVES: Post-transfusion reactions with dyspnoea (PTR) are major causes of morbidity and death after blood transfusion. Transfusion-related acute lung injury (TRALI) and transfusion-associated circulatory overload (TACO) are most dangerous, while transfusion-associated dyspnoea (TAD) is a milder respiratory distress. We investigated blood components for immune and non-immune factors implicated in PTR. MATERIAL AND METHODS: We analysed 464 blood components (RBCs, PLTs, L-PLTs, FFP) transfused to 271 patients with PTR. Blood components were evaluated for 1/antileucocyte antibodies, 2/cytokines: IL-1ß, IL-6, IL-8, TNF-α, sCD40L, 3/lysophosphatidylcholines (LysoPCs), 4/microparticles (MPs) shed from plateletes (PMPs), erythrocytes (EMPs) and leucocytes (LMPs). RESULTS: Anti-HLA class I/II antibodies or granulocyte-reactive anti-HLA antibodies were detected in 18.2% of blood components (RBC and FFP) transfused to TRALI and in 0.5% of FFP transfused to TAD cases. Cytokines and LysoPCs concentrations in blood components transfused to PTR patients did not exceed those in blood components transfused to patients with no PTR. Only EMPs percentage in RBCs transfused to patients with TRALI was significantly higher (P < 0.05) than in RBCs transfused to patients with no PTR. CONCLUSION: Immune character of PTR was confirmed mainly in 1/5 TRALI cases. Among non-immune factors, only MPs released from stored RBCs are suggested as potential mediators of TRALI. Our results require further observations in a more numerous and better defined group of patients.

Three dimensional visualisation and morphometry of bone samples studied in microcomputed tomography (micro-CT).

This article highlights the utility of micro-computed tomography (micro-CT) for characterisingmicroscale bone morphology. For this purpose we tested selected samplesof the human bones (Wormian bone, rib, lumbar vertebra) to reconstruct externaland internal morphological features. Selected bony samples were investigatedusing a micro-CT scanner (Skyscan 1172, N.V., Aartselaar, Belgium). The imageresolution of scans varied from 5 to 27 µm/pixel depending on the bone sample.We used CTvox software (by Skyscan) to perform volume rendering of the samples.Further, 3-dimensional geometrical models were reconstructed using theCTvol application. Such models enabled graphical distinction between osseouscomponents of various morphology and were used to visualise the Haversian canalsystem inside the compact bone of the rib. Applying a modified transfer functionfor volume rendering we presented the overall morphology of the Wormian boneand small vascular channels penetrating its interior. As an example of quantitativeanalysis based on micro-CT scans we compared the trabecular structure of thelumbar vertebrae with CTAn software. Significant differences in percent bonevolume (BV/TV) were determined. Micro-CT was found to be a very accurate andhelpful method to study small anatomical structures of the bones in micro scale.

Micro-computed tomography study of the abnormal osseous extensions of sella turcica.

The paper presents anatomical considerations on the abnormal ossification, which occurred around the dorsum of the sella turcica in the human skull of the female individual. Probably the morphological alterations of the sellar region were associated with extensive heterotopic ossification of the dura mater attached to the dorsum of the sella turcica and the posterior clinoid processes. The analysis of gray values of the voxels representing the areas of abnormal ossification indicated on variation in bone density in the entire sample. We have established that the highest mineralisation of bony tissue occurred in the marginal parts of the osseous extensions deriving from the posterior clinoid processes. The ossified parts of dura mater attached to the posterior clinoid processes showed significantly higher content of the hydroxyapatite (1.9 g/cm3) than the dorsum of the sella turcica (1.0 g/cm3).

Hexachlorobenzene and pentachlorobenzene accumulation, metabolism and effect on steroid secretion and on CYP11A1 and CYP19 expression in cultured human placental tissue.

Hexachlorobenzene and pentachlorobenzene accumulation and the effect on CYP1A1, SULT1A, COMT and steroid secretion in term placental tissue were determined. Explants of placental tissue were exposed to between 0.02 and 2 ng/ml HCBz or PeCBz for 6-72 h. Accumulation was measured by capillary gas chromatography and quadrupole mass spectrometry. CYP1A1, SULT1A, COMT activity and progesterone secretion were analysed by EIA. Protein expression was quantified by Western blot; 6% HCBz and 7% PeCBz were detected in the tissue. Fast induction of CYP1A1 activity and protein expression in the presence of HCBz were observed. HCBz increased, while PeCBz decreased COMT protein expression. The stimulatory effect of HCBz, and the inhibitory of PeCBz on progesterone secretion and CYP11A1 protein expression were noted. Later activation of CYP1A1, inhibition of COMT protein expression and progesterone secretion by PeCBz suggest greater exposure to PeCBz and pointing at PeCBz as the main factor responsible for the disruption of placental function.

Nuclear estrogen receptors co-activation mechanisms.

Estrogens play very important role in opening the transcription event, which is a final step of activation of the first order mediators as receptors or channels in the cell wall by information coming from the outside of the cell. For the long time the exact step by step mechanism of cellular transfer of information to the cell nuclei was not known. Currently many new informations are available. Very important seems the step of phosphorylation and therefore desensitization of the target proteins. All peptide kinases, especially serine and threonine, like protein kinases A and C, RAS and MAP kinases, cycline kinases are potential or confirmed biological targets. Except them elements of the transcription complexes like p160.SRC-1, histon acetyltransferase and histon deacetylase, CBP/p300, TRAP/DRIP, NSD1, PPARγ/PGC-1, NCOR1, SMRT, REA were also found useful. Finally estrogens are able to activate other receptors, namely aryl hydrocarbon receptors (AhR) and estrogen receptor related proteins (ERR). It is well known that many types of cancer are related to the direct or indirect excessive activation of nuclear estrogen receptors, therefore their inhibition could be crucial in many estrogen-related cancers. Understanding the interactions in such complexes would help in developing new and better multi-target cures and finding new ligands with better pharmacological and pharmacokinetic properties.

Topography and morphometry of the subarcuate canal.

The current study shows in a close-up view anatomical relationship between the subarcuate canal and the osseous labyrinth. For this purpose we used micro-computed tomography which allowed performing three-dimensional reconstruction of the subarcuate canal and gave adequate data for estimation its diameter across its course. The diameter of the middle part (the most uniform) of the subarcuate canal varied from 0.28 mm to 0.46 mm. Hence, we calculated the centre of mass for each cross-section of the separated subarcuate canal. This procedure helped us to visualise trajectory of the subarcuate canal and its spatial orientation within the petrous bone. From our data we concluded that subarcuate canals revealed not well defined trajectories and their spatial orientation varied across the studied temporal bones.

Hydroxylated estrogens (2-OH-E2 AND 4-OH-E2) do not activate cAMP/PKA and ERK1/2 pathways activation in a breast cancer MCF-7 cell line.

OBJECTIVE: The current study was undertaken to determine the involvement of cAMP/PKA and MAPK-mediated signalling pathways in the regulation of cell proliferation by hydroxylated metabolites of 17ß-estradiol (E2). METHODS: MCF-7, human breast cancer cells, were cultured in phenol red-free DMEM and treated with 1 nM 2-OH-E2 or 4-OH-E2. E2 was used as a positive control. Cell proliferation was measured using the BrdU incorporation assay. Cellular levels of cAMP and PKA were determined using ELISA kits. ERK1/2 protein expression was evaluated by Western Blot analysis. To determine the involvement of different intracellular pathways in the regulation of cell proliferation appropriate activators or inhibitors were used. RESULTS: Hydroxylated estrogens, as E2, exhibited no influence on cAMP accumulation and PKA activation. In concomitant treatments with forskolin, cell proliferation decreased to the amount noted under the influence of forskolin alone. A PKA inhibitor (PKI) had no statistically significant effect on proliferation stimulated by E2 and its hydroxylated metabolites. Phospho-ERK1/2 protein expression in cells stimulated with E2, 2-OH-E2 and 4-OH-E2 was not significantly different from the control. However, co-treatment with both PD98059 and E2 or its hydroxylated metabolites reversed the effect of tested compounds on cell proliferation. CONCLUSIONS: We have shown that E2 hydroxylated metabolites do not activate cAMP/PKA in breast cancer cells and confirm previously published data, which showed a lack of ERK1/2 activation in a breast cancer cell line. The observed reversible action of PD98059 on cell proliferation can be explained by the fact that hydroxylated estrogens, as E2, stimulate secretion of a number of growth factors, which affect MAPK activity, suggested by Lobenhofer et al. (2000).

The relevance of HPA-15 antigen expression for anti-HPA-15 antibody detection.

INTRODUCTION: The HPA-15 antigen system is characterized by a low antigen expression on platelets. The antibodies against this antigen are implied in fetal/neonatal alloimmune thrombocytopenia (F/NAIT), post-transfusion purpura, and refractoriness to platelet transfusions. Detection of these antibodies appears to be related to the level of HPA-15 expression on the platelets used in the monoclonal antibody-specific immobilization of platelet antigen (MAIPA) assay. METHODS: We performed genotyping of 300 healthy blood donors for HPA-15 by TaqMan real-time PCR technology, and the HPA-15 antigen expression was investigated in 13 HPA-15aa and 19 HPA-15bb individuals. We also investigated the relevance of HPA-15 antigen expression on donor platelets used in MAIPA for antibody detection in 223 multitransfused hematological patients and 271 women with suspected F/NAIT. RESULTS: In Polish donors, the HPA-15a allele frequencies were lower than the HPA-15b (0.480 vs. 0.515). We identified three HPA-15 expression groups: high (36.7 ± 8.36 MFI - eight cases), medium (19.5 ± 6.2 MFI - 21 cases), and low (6.5 ± 5.9 MFI - three cases). The HPA-15 expression was stable over time. The HPA-15aa and HPA-15bb platelets with high antigen expression were used for anti-HPA-15 antibody detection; anti-HPA-15 antibodies were detected in 4/223 (1.8%) patients receiving multiple transfusions but in none of the 271 women with suspected F/NAIT. Further examination of the four sera by MAIPA with various platelets revealed the optical density in the assay to be closely related to the level of HPA-15 antigen expression. CONCLUSION: Anti-HPA-15 antibody detection should be based on carefully selected platelets with high HPA-15 expression level.

The ability of hydroxylated estrogens (2-OH-E2 and 4-OH-E2) to increase of SHBG gene, protein expression and intracellular levels in MCF-7 cells line.

OBJECTIVE: Sex Hormone-Binding Globulin (SHBG) - specific carrier for sex steroids - regulates hormone bioavailable fraction and estrogen signaling system in breast cancer cells. This study was conducted to elucidate the effects of hydroxylated estrogen (E2) metabolites (2-OH-E2 and 4-OH-E2) on sex hormone binding globulin (SHBG) mRNA and protein expression as well as on intracellular and extracellular SHBG levels. METHODS: MCF-7 human breast cancer cells were cultured with 2-OH-E2 or 4-OH-E2 in concentration of 1, 10 and 100 nM for 24 h, 17ß-estradiol being used as a positive control. SHBG levels were measured in medium and cells by ELISA, SHBG mRNA expression was evaluated by real-time-PCR and protein expression by Western blot analysis. RESULTS: 4-OH-E2 in high doses and 2-OH-E2 in the highest dose, while 17ß-estradiol in all doses used increased intracellular but not extracellular SHBG levels. Both metabolites increased SHBG mRNA expression, the rank order of potency being E2 > 4-OH-E2 > 2-OH-E2. Both E2 and its metabolites increased SHBG protein expression. CONCLUSION: Although the metabolites showed a lower potency than 17ß-estradiol, further studies are needed to clarify whether hydroxylated metabolites of E2 are potent ligands for SHBG.

The involvement of NMDA and AMPA receptors in the mechanism of antidepressant-like action of zinc in the forced swim test.

Antidepressant-like activity of zinc in the forced swim test (FST) was demonstrated previously. Enhancement of such activity by joint administration of zinc and antidepressants was also shown. However, mechanisms involved in this activity have not yet been established. The present study examined the involvement of the NMDA and AMPA receptors in zinc activity in the FST in mice and rats. Additionally, the influence of zinc on both glutamate and aspartate release in the rat brain was also determined. Zinc-induced antidepressant-like activity in the FST in both mice and rats was antagonized by N-methyl-D-aspartic acid (NMDA, 75 mg/kg, i.p.) administration. Moreover, low and ineffective doses of NMDA antagonists (CGP 37849, L-701,324, D-cycloserine, and MK-801) administered together with ineffective doses of zinc exhibit a significant reduction of immobility time in the FST. Additionally, we have demonstrated the reduction of immobility time by AMPA receptor potentiator, CX 614. The antidepressant-like activity of both CX 614 and zinc in the FST was abolished by NBQX (an antagonist of AMPA receptor, 10 mg/kg, i.p.), while the combined treatment of sub-effective doses of zinc and CX 614 significantly reduces the immobility time in the FST. The present study also demonstrated that zinc administration potentiated a veratridine-evoked glutamate and aspartate release in the rat's prefrontal cortex and hippocampus. The present study further suggests the antidepressant properties of zinc and indicates the involvement of the NMDA and AMPA glutamatergic receptors in this activity.

Towards electrophysiological correlates of auditory perception of temporal order.

Recent studies have postulated that the temporal order (TO) of two successive events can be correctly identified if they are separated by an inter-stimulus interval (ISI) of at least 30 ms duration. Using Auditory Evoked Potentials, we tested 21 students for the cortical activation associated with TO detection of two successively presented tones in either 'easy' (ISI=60 ms) or 'difficult' (ISI=10 ms) conditions. The amplitude of P2 component was related to difficulty of TO perception and was significantly higher in 'difficult' than 'easy' condition. Moreover, in 'difficult' condition the correlation analyses revealed a negative association at both Fz and Cz electrodes between P2 amplitudes and the correctness level. Correct responses in this condition were accompanied by lower P2 amplitudes than the incorrect ones.

K-ras gene point mutations and p21ras immunostaining in human ovarian tumors.

It is well recognized that genetic alterations within oncogenes, tumor suppressor genes, DNA mismatch repair and excision repair genes contribute to tumorigenesis within the human ovary. This study was undertaken to screen for the existence of K-ras gene point mutations in paraffin-embedded slides randomly selected from benign and malignant ovarian tumors applying the PCR-RFLP technique. Expression of p21ras was also assessed in 30 primary ovarian adenocarcinomas immunohistochemically. K-ras codon 12 point mutations occurred in nine of 40 (22.5%) cases. They were not identified in two benign mucinous cystadenomas, but in one out of two (50%) mucinous tumors of LMP (low malignant potential), in five out of 30 (17%) ovarian adenocarcinomas, and in one case of adenocarcinoma metastatic to the ovary. K-ras activation was also detected in one out of four (25%) sex cord-stromal cell tumors (folliculoma), and in one dysgerminoma. None of these tumors exhibited K-ras codon 13 point mutations. Gene alterations were more frequently found in mucinous than in non-mucinous (30% vs 10%) tumors, although the difference did not reach significance (p > 0.05). The frequency of K-ras point mutations was correlated neither with clinical nor with pathological variables of cancer. Cytoplasmic p21ras was expressed in all adenocarcinomas negative for K-ras point mutations, whereas one of five (20%) K-ras-positive tumors exhibited lack of immunoreactivity. In conclusion, these findings confirm the role of K-ras activation in mucinous ovarian tumors. p21ras expression is not necessarily associated with K-ras gene alterations in human ovarian adenocarcinomas.

Electron paramagnetic resonance study of erythrocyte membrane fluidity in renal transplant recipients.

Renal transplantation (KTx) patients receiving calcineurin inhibitors-cyclosporine (CsA) or tacrolimus (TAC)-are known to be at risk for the development of posttransplant hemolytic uremic syndrome. The syndrome has been reported to occur more often with CsA than TAC treatment. It has also been noted that CsA affects erythrocyte membrane fluidity. The aim of this study was to investigate whether the impairment of erythrocyte membrane fluidity is similar among patients under treatment with different calcineurin inhibitors (CsA or TAC). Venous blood was collected from 29 KTx patients and from nine healthy volunteers. To investigate the fluidity of intact erythrocyte membranes spin label electron paramagnetic resonance spectroscopy was applied. Comparison of values for controls versus CsA-treated patients demonstrated a significant decrease in membrane viscosity in the hydrophobic region of the lipid bilayer among CsA-treated patients, whereas there was no significant difference between control and patients treated with TAC. There was no significant difference in the molecular order close to the polar heads of lipid molecules among all groups. The observed changes in erythrocyte membrane fluidity among CsA-treated patients and the lack of this phenomenon in the TAC group may correlate with more frequent prevalence of hemolytic anemia among CsA than TAC-treated patients.

Effect of repeated treatment with mirtazapine on the central alpha1-adrenergic receptors.

Mirtazapine (MIR) is an antidepressant which enhances noradrenergic and serotonergic 5-HT1A neurotransmission via antagomism of central alpha2-adrenergic autoreceptors and heteroreceptors. The drugs does not inhibit noradrenaline and serotonin reuptake but blocks the 5-HT, and 5-HT3 receptors and has high affinity only for central and peripheral histamine H1 receptors. The present study was aimed at determining whether repeated MIR treatment induced adaptive changes in the alpha1-adrenergic receptors, similar to those reported by us early for tricyclic antidepressants, The experiments were carried out on male mice and rats. MIR was administered at a dose of 10 mg/kg once or repeatedly (twice daily for 14 days). The obtained results showed that MIR administrated repeatedly potentiated the methoxamine- induced exploratory hyperactivity in rats and clonidine-induced aggressiveness in mice, those effects being mediated by alpha1-adrenergic receptors. MIR given repeatedly (but not acutely) increased the binding (Bmax ) of [3H]prazosin to alpha1-adrenergic receptors in cerebral cortex, however, the ability of the alpha1-adrenoceptor agonist phenylephrine to compete for the these sites was not significantly changed. The above results indicate that repeated MIR administration increases the responsiveness of alpha1-adrenergic system (behavioural and biochemical changes), as tricyclics do. However, the question whether the increased functional responsiveness found in the present study is important for the clinical antidepressant efficacy, remains open.

Decrease in 2,2,6,6-tetramethyl-piperidine-1-oxyl (TEMPO) EPR signal in peroxynitrite-treated erythrocyte membranes.

The treatment of erythrocyte membranes with peroxynitrite (ONOO-), a cytotoxic species formed in vivo by the almost completely diffusion controlled reaction of nitric oxide (NO*) and the superoxide anion (O2*-), led to the loss of the EPR signal of the nitroxide radical 2,2,6,6-tetramethyl-piperidine-1-oxyl (TEMPO). The decrease in the TEMPO EPR signal was peroxynitrite concentration dependent in the studied peroxynitrite concentration range (100-1000 microM). The absence of such a phenomenon in the control membranes (not treated with peroxynitrite) and in a buffer treated with peroxynitrite indicates that the effect must be caused by nitroxide radicals reacting with the products of peroxynitrite reactions with membrane components. To find out which membrane components are responsible for the decrease in EPR signal, this effect was studied in simple model systems (protein and lipid suspensions). The same phenomenon was observed in both lipid and protein systems treated with peroxynitrite, but in protein solutions the effect was greater and occurred for lower peroxynitrite concentrations. A clear effect of the loss of the EPR signal was observed for both erythrocyte membranes and bovine serum albumin (BSA) solution for a peroxynitrite concentration of 100 microM, while in the case of linolenic acid suspension, a significant difference between control and peroxynitrite-treated samples was achieved for a peroxynitrite concentration of 1000 microM. A comparison of the results obtained for the lipid and protein systems suggests that the reaction of nitroxide radicals with protein derived species plays the main role in the observed decrease in the TEMPO EPR signal in peroxynitrite treated erythrocyte membranes.

The spatial substructure of visual receptive fields in the cat's superior colliculus.

Although the direction selective properties of the superficial layer cells of the cat's superior colliculus have been extensively studied, the mechanisms underlying this property remain controversial. With the aim to understand the mechanism(s) underlying directional selectivity of collicular neurons we examined the substructure of their visual receptive fields. 1. The strength of cell responses and the direction selectivity indices varied in relation to the location of the tested region within the receptive field and the amplitude of stimulus movement. 2. Decrease of the amplitude of motion resulted in a decrease of direction selectivity index both in the group of direction-selective cells and in the group of cells classified as direction nonselective but with a directional bias. 3. The decrease of direction selectivity for small amplitude movement resulted mainly from increase in the magnitude of response in the nonpreferred direction of movement. 4. These results suggest that the receptive fields of most collicular cells are composed of subregions with different response profiles and indicate that inhibitory mechanisms dictate direction selectivity of collicular cells.

Identification of principal components in cortical evoked potentials by brief surface cooling.

OBJECTIVES: The evoked potential recorded by a single electrode in rat's barrel cortex after whisker stimulation was shown to be composed of two main principal components shifted in time by about 3 ms. The purpose of this study was to verify the hypothesis that these components represent activity of supra- and infragranular pyramidal cell classes. RESULTS: Our results show that a brief cooling pulse applied to the cortical surface abolishes the shorter latency component, which may therefore be attributed to the response of supragranular pyramidal cells. CONCLUSIONS: The longer latency principal component, which disappears only with strong cooling pulses, is proposed to represent postsynaptic activity of infragranular pyramidal neurons.

Monitoring of MRP-like activity in human erythrocytes: inhibitory effect of isoflavones.

A method to fluorometrically monitor efflux of 2',7'-bis-(carboxypropyl)-5(6)-carboxyfluorescein (BCPCF) from human erythrocytes was developed. Genistein, daidzein, sophoraisoflavone A, and licoisoflavone A induced 50% inhibition (IC(50)) of BCPCF efflux at 15-70 microM. The IC(50) value of the most efficient isoflavone, licoisoflavone A (15-25 microM), was comparable to that of indomethacin (approximately 10 microM) and markedly lower than for probenecid (100-200 microM), both known MRP1 inhibitors. Our results indicate that the human erythrocyte is a useful cell model in screening potential MRP inhibitors, that BCPCF is a good substrate for MRP, and that some isoflavones at low concentrations inhibit MRP-mediated efflux.