Functionalization of graphene nanostructures with inorganic nanoparticles and their use for the removal of pharmaceutical pollutants in water

Emerging pollutants such as pharmaceuticals are of special concern because despite their low environmental concentration, their biological activity can be intense, and they should be prevented to reach uncontrolledly to the environment. A graphene-based hybrid material decorated with Fe3O4 and TiO2 nanoparticles (NPs) has been prepared to effectively remove emerging pollutants as nonsteroidal anti-inflammatory drugs (NSAIDs) Ibuprofen and Diclofenac present in water at low environmental concentrations by a one-step functionalization process following a novel gentle and scalable surfactant depletion approach. Following this methodology, nanoparticles are progressively deprived of their original surfactant in the presence of graphene, leading to the formation of hybrid nanostructures composed of two different types of nanoparticles well dispersed over the graphene nanosheets. Ibuprofen and Diclofenac adsorption kinetics on the composites was investigated via UV-Vis spectroscopy. The as prepared hybrid material possesses high adsorption capacity, superparamagnetic properties, photocatalytic behavior, and good water dispersibility. Thanks to incorporating TiO2 nanoparticles as in situ catalysts, the adsorption performance of composites is restored after use, which could be a promising recycling pathway for the adsorbents in wastewater treatments.

Therapeutic efficacy of 166Holmium siloxane in microbrachytherapy of induced glioblastoma in minipig tumor model

Glioblastoma is considered the most common malignant primary tumor of central nervous system. In spite of the current standard and multimodal treatment, the prognosis of glioblastoma is poor. For this reason, new therapeutic approaches need to be developed to improve the survival time of the glioblastoma patient. In this study, we performed a preclinical experiment to evaluate therapeutic efficacy of 166Ho microparticle suspension administered by microbrachytherapy on a minipig glioblastoma model. Twelve minipigs were divided in 3 groups. Minipigs had injections into the tumor, containing microparticle suspensions of either 166Ho (group 1; n = 6) or 165Ho (group 2; n = 3) and control group (group 3; n = 3). The survival time from treatment to euthanasia was 66 days with a good state of health of all minipigs in group 1. The median survival time from treatment to tumor related death were 8.6 and 7.3 days in groups 2 and control, respectively. Statistically, the prolonged life of group 1 was significantly different from the two other groups (p < 0.01), and no significant difference was observed between group 2 and control (p=0.09). Our trial on the therapeutic effect of the 166Ho microparticle demonstrated an excellent efficacy in tumor control. The histological and immunohistochemical analysis showed that the efficacy was related to a severe 166Ho induced necrosis combined with an immune response due to the presence of the radioactive microparticles inside the tumors. The absence of reflux following the injections confirms the safety of the injection device.

P377 CHALLENGING RISK STRATIFICATION IN BRUGADA SYNDROME: A CASE OF VENTRICULAR TACHYCARDIA IN A LOW–RISK PATIENT

A 22–year–old healthy athlete was referred to our hospital for electrocardiographic findings consistent with intermittent type–1 Brugada pattern. A routine electrocardiogram (ECG) performed during a check–up showed sinus rhythm, normal PR interval and QRS duration, rSR’ with a coved type ST–segment elevation in V2 lead (Figure 1).The patients denied history of syncope or palpitations and his family history did not show sudden cardiac death or Brugada syndrome (BrS). Transthoracic echocardiography was normal and a 12–lead Holter monitoring revealed the intermittence of the type–1 Brugada pattern. The patient was hospitalized for further investigation. On admission, ECG showed a type–2 Brugada pattern; therefore, Ajmaline challenge test (1 mg/kg injection in 10 minutes) was performed and resulted positive. Subsequently, the patient underwent an electrophysiological study (EPS) which was negative for induction of sustained arrhythmias. The protocol adopted consisted of double extrastimuli programmed electrical stimulation until refractoriness (drive 600/220 ms and 400/210 ms), at double sites (right ventricle apex and right ventricular outflow tract). Furthermore a genetic test was performed using next–generation sequencing, showing a heterozygous mutation in the SCN5A gene, encoding for sodium channel alpha subunit (variant c.5363delA), not previously described in the literature. Since the low arrhythmic risk, the patient was implanted with a loop recorder (ILR, Medtronic Reveal LINQ), entering a program of home monitoring. After a 15–months follow–up, an episode of ventricular polymorphic tachycardia lasting 2 minutes and 11 seconds, associated with lightheadedness and palpitations, was detected by the remote monitoring (Figure 2). The patient was therefore hospitalized. During the in–hospital stay a cardiac magnetic resonance was performed to exclude other underlying diseases, identifying an enlarged right ventricle (EDVi 114 ml/m2) and abnormal free wall motion (Figure 3), thus reaching one major criteria of arrhythmogenic cardiomyopathy (however not sufficient for the diagnosis). The patient was then implanted with a subcutaneous implantable cardiac defibrillator (Boston Scientific EMBLEM MRI S–ICD). We presented a case of complex arrhythmic risk stratification in a possible overlap of an arrhythmogenic cardiomyopathy and a Brugada Syndrome in a young athlete who experienced a sustained ventricular tachycardia during loop–recorder monitoring.

Current and future chemical treatments to fight biodeterioration of outdoor building materials and associated biofilms: Moving away from ecotoxic and towards efficient, sustainable solutions

All types of building materials are rapidly colonized by microorganisms, initially through an invisible and then later a visible biofilm that leads to their biodeterioration. Over centuries, this natural phenomenon has been managed using mechanical procedures, oils, or even wax. In modern history, many treatments such as high-pressure cleaners, biocides (mainly isothiazolinones and quaternary ammonium compounds) are commercially available, as well as preventive ones, such as the use of water-repellent coatings in the fabrication process. While all these cleaning techniques offer excellent cost-benefit ratios, their limitations are numerous. Indeed, building materials are often quickly recolonized after application, and microorganisms are increasingly reported as resistant to chemical treatments. Furthermore, many antifouling compounds are ecotoxic, harmful to human health and the environment, and new regulations tend to limit their use and constrain their commercialization. The current state-of-the-art highlights an urgent need to develop innovative antifouling strategies and the widespread use of safe and eco-friendly solutions to biodeterioration. Interestingly, innovative approaches and compounds have recently been identified, including the use of photocatalysts or natural compounds such as essential oils or quorum sensing inhibitors. Most of these solutions developed in laboratory settings appear very promising, although their efficiency and ecotoxicological features remain to be further tested before being widely marketed. This review highlights the complexity of choosing the adequate antifouling compounds when fighting biodeterioration and proposes developing case-to-case innovative strategies to raise this challenge, relying on integrative and multidisciplinary approaches.

In situ nanoremediation of soils and groundwaters from the nanoparticle's standpoint: A review

Anthropogenic pollution coming from industrial processes, agricultural practices and consumer products, results in the release of toxic substances into rural and urban environments. Once released, these chemicals migrate through the atmosphere and water, and find their way into matrices such as sediments and groundwaters, thus making large areas potentially uninhabitable. Common pollutants, including heavy metal(loid)s, radionuclides, aliphatic hydrocarbons and halogenated organics, are known to adversely affect physiological systems in animal species. Pollution can be cleaned up using techniques such as coagulation, reverse osmosis, oxidation and biological methods, among others. The use of nanoparticles (NPs) extends the range of available technologies and offers particular benefits, not only by degrading, transforming and immobilizing contaminants, but also by reaching inaccessible areas and promoting biotic degradation. The development of NPs is understandably heralded as an environmentally beneficial technology; however, it is only now that the ecological risks associated with their use are being evaluated. This review presents recent developments in the use of engineered NPs for the in situ remediation of two paramount environmental matrices: soils and groundwaters. Emphasis will be placed on (i) the successful applications of nano-objects for environmental cleanup, (ii) the potential safety implications caused by the challenging requirements of [high reactivity toward pollutants] vs. [none reactivity toward biota], with a thorough view on their transport and evolution in the matrix, and (iii) the perspectives on scientific and regulatory challenges. To this end, the most promising nanomaterials will be considered, including nanoscale zerovalent iron, nano-oxides and carbonaceous materials. The purpose of the present review is to give an overview of the development of nanoremediators since they appeared in the 2000s, from their chemical modifications, mechanism of action and environmental behavior to an understanding of the problematics (technical limitations, economic constraints and institutional precautionary approaches) that will drive their future full-scale applications.

Feasibility of intratumoral 165Holmium siloxane delivery to induced U87 glioblastoma in a large animal model, the Yucatan minipig

Glioblastoma is the most aggressive primary brain tumor leading to death in most of patients. It comprises almost 50-55% of all gliomas with an incidence rate of 2-3 per 100,000. Despite its rarity, overall mortality of glioblastoma is comparable to the most frequent tumors. The current standard treatment combines surgical resection, radiotherapy and chemotherapy with temozolomide. In spite of this aggressive multimodality protocol, prognosis of glioblastoma is poor and the median survival remains about 12-14.5 months. In this regard, new therapeutic approaches should be developed to improve the life quality and survival time of the patient after the initial diagnosis. Before switching to clinical trials in humans, all innovative therapeutic methods must be studied first on a relevant animal model in preclinical settings. In this regard, we validated the feasibility of intratumoral delivery of a holmium (Ho) microparticle suspension to an induced U87 glioblastoma model. Among the different radioactive beta emitters, 166Ho emits high-energy β(-) radiation and low-energy γ radiation. β(-) radiation is an effective means for tumor destruction and γ rays are well suited for imaging (SPECT) and consequent dosimetry. In addition, the paramagnetic Ho nucleus is a good asset to perform MRI imaging. In this study, five minipigs, implanted with our glioblastoma model were used to test the injectability of 165Ho (stable) using a bespoke injector and needle. The suspension was produced in the form of Ho microparticles and injected inside the tumor by a technique known as microbrachytherapy using a stereotactic system. At the end of this trial, it was found that the 165Ho suspension can be injected successfully inside the tumor with absence or minimal traces of Ho reflux after the injections. This injection technique and the use of the 165Ho suspension needs to be further assessed with radioactive 166Ho in future studies.

Self-crosslinked fibrous collagen/chitosan blends: Processing, properties evaluation and monitoring of degradation by bi-fluorescence imaging

Porous collagen/chitosan scaffolds with different Collagen:Chitosan (Coll:Ch) ratios were prepared by freeze-drying followed by self-crosslinking via dehydrothermal treatment (DHT) and characterized as biomaterials for tissue engineering. Cy7 and Cy5.5 fluorochromes were covalently grafted to collagen and chitosan, respectively. Thus, it was possible, using optical fluorescence imaging of the two fluorochromes, to simultaneously track their in vivo biodegradation, in a blend scaffold form. The fluorescence signal evolution, due to the bioresorption, corroborated with histological analysis. In vitro cytocompatibility of Coll:Ch blend scaffolds were evaluated with standardized tests. In addition, the scaffolds showed a highly interconnected porous structure. Extent of crosslinking was analyzed by convergent analysis using thermogravimetry, Fourier Transform Infrared Spectroscopy and PBS uptake. The variations observed with these techniques indicate strong interactions between collagen and chitosan (covalent and hydrogen bonds) promoted by the DHT. The mechanical properties were characterized to elucidate the impact of the different processing steps in the sample preparation (DHT, neutralization and sterilization by β-irradiation) and showed a robust processing scheme with low impact of Coll:Ch composition ratio.

Modeling digits. Digit patterning is controlled by a Bmp-Sox9-Wnt Turing network modulated by morphogen gradients

During limb development, digits emerge from the undifferentiated mesenchymal tissue that constitutes the limb bud. It has been proposed that this process is controlled by a self-organizing Turing mechanism, whereby diffusible molecules interact to produce a periodic pattern of digital and interdigital fates. However, the identities of the molecules remain unknown. By combining experiments and modeling, we reveal evidence that a Turing network implemented by Bmp, Sox9, and Wnt drives digit specification. We develop a realistic two-dimensional simulation of digit patterning and show that this network, when modulated by morphogen gradients, recapitulates the expression patterns of Sox9 in the wild type and in perturbation experiments. Our systems biology approach reveals how a combination of growth, morphogen gradients, and a self-organizing Turing network can achieve robust and reproducible pattern formation.

The antimicrobial effect of silicon nanowires decorated with silver and copper nanoparticles

The paper reports on the preparation and antibacterial activity of silicon nanowire (SiNW) substrates coated with Ag or Cu nanoparticles (NPs) against Escherichia coli (E. coli) bacteria. The substrates are easily prepared using the metal-assisted chemical etching of crystalline silicon in hydrofluoric acid/silver nitrate (HF/AgNO3) aqueous solution. Decoration of the SiNWs with metal NPs is achieved by simple immersion in HF aqueous solutions containing silver or copper salts. The SiNWs coated with Ag NPs are biocompatible with human lung adenocarcinoma epithelial cell line A549 while possessing strong antibacterial properties to E. coli. In contrast, the SiNWs decorated with Cu NPs showed higher cytotoxicity and slightly lower antibacterial activity. Moreover, it was also observed that leakage of sugars and proteins from the cell wall of E. coli in interaction with SiNWs decorated with Ag NPs is higher compared to SiNWs modified with Cu NPs.

Cell micropatterning on superhydrophobic diamond nanowires

Cell micropatterning was achieved in a spatially controlled manner based on heterogeneously wetted superhydrophilic/superhydrophobic diamond nanowire (NW) surfaces. Diamond NWs were synthesized on boron-doped diamond substrates using reactive ion etching and functionalized with octadecyltrichlorosilane to achieve superhydrophobicity. Superhydrophilic motifs of 400×400 μm(2) and 10×10 μm(2) single cell-sized motifs, surrounded by superhydrophobic regions, were then generated by selectively exposing the substrates to UV light. This design allowed successful patterning of single HeLa and MCF-10A cells within the superhydrophilic regions without additional surface modification. To add a further level of complexity, micropatterned co-cultures were obtained using bovine serum albumin to promote cell adhesion. This method is simple and does not require any complicated processing steps such as mask deposition or template removal. Potential applications are in the development of cell-based biological assays in well-controlled and biologically relevant environments.

Cell adhesion properties on chemically micropatterned boron-doped diamond surfaces

The adhesion properties of living cells were investigated on a range of chemically modified boron-doped diamond (BDD) surfaces. We studied the influence of oxidized, H-, amine- (NH(2)-), methyl- (CH(3)-), trifluoromethyl- (CF(3)-) and vinyl- (CH(2)═CH-) terminated BDD surfaces on human osteosarcoma U2OS and mouse fibroblast L929 cells behavior. Cell-surface interactions were analyzed by fluorescence microscopy in terms of cell attachment, spreading and proliferation. U2OS cells poorly adhered on hydrophobic surfaces and their growth was blocked. In contrast, L929 cells were mainly influenced by the presence of perfluoroalkyl chains in regard to their morphology. The results were subsequently applied to selectively micropattern U2OS cells on dual hydrophobic/hydrophilic surfaces prepared by a UV/ozone lithographic approach. U2OS cells colonized preferentially hydrophilic (oxide-terminated) motifs, forming confluent arrays with distinguishable edges separating the alkyl regions.

Functionalization of diamond nanoparticles using "click" chemistry

The paper reports on covalent linking of different alkyne-containing (decyne, ethynylferrocene, and N-propargyl-1-pyrenecarboxamide) compounds to azide-terminated nanodiamond (ND) particles. Azide-terminated particles (ND-N(3)) were obtained from amine-terminated nanodiamond particles (ND-NH(2)) through the reaction with 4-azidobenzoic acid in the presence of a carbodiimide coupling agent. Functionalized ND particles with long alkyl chain groups can be easily dispersed in various organic solvents without any apparent precipitation after several hours. The course of the reaction was followed using Fourier transform infrared (FT-IR) spectroscopy, UV/vis spectroscopy, fluorescence, cyclic voltammetry, thermogravimetric analysis (TGA), and particle size measurements. The surface loading of pyrene bearing a terminal acetylene group was found to be 0.54 mmol/g. Because of its gentle nature and specificity, the chemistry developed in this work can be used as a general platform for the preparation of functional nanoparticles for various applications.

Photochemical immobilization of proteins and peptides on benzophenone-terminated boron-doped diamond surfaces

The successful covalent linking of green fluorescence protein and streptavidin to patterned benzophenone-modified boron-doped diamond (BDD) electrodes is demonstrated. Photoreactive benzophenone moieties were covalently grafted to oxidized diamond surfaces via an esterification reaction. Patterned BDD surfaces were obtained using a UV/ozone lithographic approach either on hydrogen-terminated BDD or on poly(ethylene)-glycol-modified BDD surfaces. UV light (lambda = 365 nm) irradiation of the patterned BDD surfaces in the presence of green fluorescence protein (GFP) or streptavidin resulted in the covalent immobilization of the proteins. The presence of poly(ethylene) glycol chains reduces significantly the nonspecific adsorption of the proteins. The success of the photoimmobilization of streptavidin was evidenced through biomolecular interaction with avidin. The preservation of the biological activity was furthermore underlined by photoimmobilization of peptides directly onto benzophenone modified BDD using a photomask.

'On-the-fly' optical encoding of combinatorial peptide libraries for profiling of protease specificity

Large solid-phase combinatorial libraries currently play an important role in areas such as infectious disease biomarker discovery, profiling of protease specificity and anticancer drug discovery. Because compounds on solid support beads are not positionally-encoded as they are in microarrays, innovative methods of encoding are required. There are many advantages associated with optical encoding and several strategies have been described in the literature to combine fluorescence encoding methods with solid-phase library synthesis. We have previously introduced an alternative fluorescence-based encoding method ("colloidal barcoding"), which involves encoding 10-20 mum support beads during a split-and-mix synthesis with smaller 0.6-0.8 mum silica colloids that contain specific and identifiable combinations of fluorescent dye. The power of this 'on-the-fly' encoding approach lies in the efficient use of a small number of fluorescent dyes to encode millions of compounds. Described herein, for the first time, is the use of a colloid-barcoded library in a biological assay (i.e., protease profiling) combined with the use of confocal microscopy to decode the colloidal barcode. In this proof-of-concept demonstration, a small focussed peptide library was optically-encoded during a combinatorial synthesis, incubated with a protease (trypsin), analysed by flow cytometry and decoded via confocal microscopy. During assay development, a range of parameters were investigated and optimised, including substrate (or probe) loading, barcode stability, characteristics of the peptide-tagging fluorophore, and spacer group configuration. Through successful decoding of the colloidal barcodes, it was confirmed that specific peptide sequences presenting one or two cleavage sites were recognised by trypsin while peptide sequences not cleavable by trypsin remained intact.

Flow cytometric detection of proteolysis in peptide libraries synthesised on optically encoded supports

The concept of optically encoding particles for solid phase organic synthesis has existed in the literature for several years. However, there remains a significant challenge to producing particles that are capable of withstanding harsh solvents and reagents whilst maintaining the integrity and range of the optical encoding. In this study, a new generation of fluorescently encoded support particles was used for both solid phase peptide synthesis and on-particle analysis of proteolysis in a multiplexed, flow cytometric assay. The success of the assay was demonstrated through the use of a model protease, trypsin. Our results show that the use of solid supports with high peptide yield, high swellability in water and high penetration of the enzyme into the interior of the particle is not absolutely necessary for proteolysis assays.

Electrical detection of human immunoglobulins G from human serum using a microbiosensor

A biosensor for the electrical detection of human antibodies from serum has been fabricated and experimentally demonstrated. The device is based on the immobilization of proteins used as probes between a set of microelectrodes. Incubation with diluted human serum was followed by incubation with anti-human secondary antibodies labeled with gold nanoparticles (GNPs) and then precipitation of silver on the nanoparticles. The output of the device was defined as the percentage of short-circuited microelectrodes after silver deposition independently of the gap conductance. Two model probes were studied: protein A and goat antibodies. The effects of the microgap spacing (5, 10, 15 or 20 microm) and the duration of the silver treatment were examined. The data obtained showed that a large spacing (20 microm) led to poor sensitivity. Alternately, 5 microm gaps led to high sensitivity and saturation of the signal. Interestingly, 10-15 microm gaps enabled a non-saturated and distinct signal for both probes that was correlated with the GNP density between the microgaps as determined by atomic force microscopy. Different capture efficiencies could be easily distinguished. The biosensor described here is easy to use and thus can be applied to real detection experiments.

Fluidics of a nanogap

We have determined the filling properties of nanogaps with chemically heterogeneous walls. The quantitative criteria we present allow the prediction of the liquid loading of the nanostructure. They can easily be applied in combination with contact-angle measurements on planar substrates of the nanogap materials. We present an application of the theory to a recently developed nanogap biosensor. Chemical force microscopy (CFM) is employed to characterize the initial silanol properties of the gap. The functionality of the complex surface chemistry of the biosensor is demonstrated by the observation of functionalized nanoparticles in the gap with its resulting characteristic current-voltage relationship.

Effects of soluble CD4 on simian immunodeficiency virus infection of CD4-positive and CD4-negative cells

A soluble form of the CD4 receptor (sCD4) can either enhance or inhibit the infection of cells by simian immunodeficiency virus (SIV) and human immunodeficiency virus. We investigated the basis for these varying effects by studying the entry of three SIV isolates into CD4-positive and CD4-negative cells expressing different chemokine receptors. Infection of CD4-negative cells depended upon the viral envelope glycoproteins and upon the chemokine receptor, with CCR5 and gpr15 being more efficient than STRL33. Likewise, enhancement of infection by sCD4 was observed when CCR5- and gpr15-expressing target cells were used but not when those expressing STRL33 were used. The sCD4-mediated enhancement of virus infection of CD4-negative, CCR5-positive cells was related to the sCD4-induced increase in binding of the viral gp120 envelope glycoprotein to CCR5. Inhibitory effects of sCD4 could largely be explained by competition for virus attachment to cellular CD4 rather than other detrimental effects on virus infectivity (e.g., disruption of the envelope glycoprotein spike). Consistent with this, the sCD4-activated SIV envelope glycoprotein intermediate on the virus was long-lived. Thus, the net effect of sCD4 on SIV infectivity appears to depend upon the degree of enhancement of chemokine receptor binding and upon the efficiency of competition for cellular CD4.

The envelope glycoprotein ectodomains determine the efficiency of CD4+ T lymphocyte depletion in simian-human immunodeficiency virus-infected macaques

CD4+ T lymphocyte depletion in human immunodeficiency virus type 1 (HIV-1)-infected humans underlies the development of acquired immune deficiency syndrome. Using a model in which rhesus macaques were infected with chimeric simian-human immunodeficiency viruses (SHIVs), we show that both the level of viremia and the structure of the HIV-1 envelope glycoprotein ectodomains individually contributed to the efficiency with which CD4(+) T lymphocytes were depleted. The envelope glycoproteins of recombinant SHIVs that efficiently caused loss of CD4(+) T lymphocytes exhibited increased chemokine receptor binding and membrane-fusing capacity compared with those of less pathogenic viruses. These studies identify the HIV-1 envelope glycoprotein ectodomains as determinants of CD4(+) T lymphocyte loss in vivo and provide a foundation for studying pathogenic mechanisms.

The orphan seven-transmembrane receptor apj supports the entry of primary T-cell-line-tropic and dualtropic human immunodeficiency virus type 1

Human immunodeficiency virus type 1 (HIV-1) enters target cells by sequential binding to CD4 and specific seven-transmembrane-segment (7TMS) coreceptors. Viruses use the chemokine receptor CCR5 as a coreceptor in the early, asymptomatic stages of HIV-1 infection but can adapt to the use of other receptors such as CXCR4 and CCR3 as the infection proceeds. Here we identify one such coreceptor, Apj, which supported the efficient entry of several primary T-cell-line tropic (T-tropic) and dualtropic HIV-1 isolates and the simian immunodeficiency virus SIVmac316. Another 7TMS protein, CCR9, supported the less efficient entry of one primary T-tropic isolate. mRNAs for both receptors were present in phytohemagglutinin- and interleukin-2-activated peripheral blood mononuclear cells. Apj and CCR9 share with other coreceptors for HIV-1 and SIV an N-terminal region rich in aromatic and acidic residues. These results highlight properties common to 7TMS proteins that can function as HIV-1 coreceptors, and they may contribute to an understanding of viral evolution in infected individuals.

CD4-independent binding of SIV gp120 to rhesus CCR5

CCR5 and CD4 are coreceptors for immunodeficiency virus entry into target cells. The gp120 envelope glycoprotein from human immunodeficiency virus strain HIV-1(YU2) bound human CCR5 (CCR5hu) or rhesus macaque CCR5 (CCR5rh) only in the presence of CD4. The gp120 from simian immunodeficiency virus strain SIVmac239 bound CCR5rh without CD4, but CCR5hu remained CD4-dependent. The CD4-independent binding of SIVmac239 gp120 depended on a single amino acid, Asp13, in the CCR5rh amino-terminus. Thus, CCR5-binding moieties on the immunodeficiency virus envelope glycoprotein can be generated by interaction with CD4 or by direct interaction with the CCR5 amino-terminus. These results may have implications for the evolution of receptor use among lentiviruses as well as utility in the development of effective intervention.

Two orphan seven-transmembrane segment receptors which are expressed in CD4-positive cells support simian immunodeficiency virus infection

Clinical isolates of primate immunodeficiency viruses, including human immunodeficiency virus type 1 (HIV-1), enter target cells by sequential binding to CD4 and the chemokine receptor CCR5, a member of the seven-transmembrane receptor family. HIV-1 variants which use additional chemokine receptors are present in the central nervous system or emerge during the course of infection. Simian immunodeficiency viruses (SIV) have been shown to use CCR5 as a coreceptor, but no other receptors for these viruses have been identified. Here we show that two orphan seven-transmembrane segment receptors, gpr1 and gpr15, serve as coreceptors for SIV, and are expressed in human alveolar macrophages. The more efficient of these, gpr15, is also expressed in human CD4(+) T lymphocytes and activated rhesus macaque peripheral blood mononuclear cells. The gpr15 and gpr1 proteins lack several hallmarks of chemokine receptors, but share with CCR5 an amino-terminal motif rich in tyrosine residues. These results underscore the potential diversity of seven-transmembrane segment receptors used as entry cofactors by primate immunodeficiency viruses, and may contribute to an understanding of viral variation and pathogenesis.

High degree of sensitivity of the simian immunodeficiency virus (SIVmac) envelope glycoprotein subunit association to amino acid changes in the glycoprotein 41 ectodomain

The infection of macaques by simian immunodeficiency virus (SIVmac) represents an attractive model to study the pathogenic determinants of primate and human immunodeficiency viruses. The utility of this model would be enhanced if genetic changes in human immunodeficiency virus (HIV-1) associated with interesting in vitro properties would, when introduced into SIVmac, result in similar phenotypes. In this study, we introduced amino acid changes into the SIVmac239 envelope glycoproteins that, in the context of the HIV-1 envelope glycoproteins, disproportionately attenuated in vitro cytopathic effects compared with the viral replication rate. Amino acid changes in the SIVmac239 gp41 ectodomain altered the noncovalent association of the gp120 and gp41 glycoproteins significantly more than did analogous changes in the HIV-1 envelope glycoproteins. Decreases in the affinity of the gp120-gp41 interaction were observed and were associated with a dramatic attenuation of virus replication not seen in the HIV-1 studies. The increased sensitivity of the SIVmac gp120-gp41 interaction to amino acid changes presents an obstacle to the direct extension of results obtained with the HIV-1 envelope glycoproteins to the SIVmacaque model.

Utilization of C-C chemokine receptor 5 by the envelope glycoproteins of a pathogenic simian immunodeficiency virus, SIVmac239

We examined chemokine receptors for the ability to facilitate the infection of CD4-expressing cells by viruses containing the envelope glycoproteins of a pathogenic simian immunodeficiency virus, SIVmac239. Expression of either human or simian C-C chemokine receptor CCR5 allowed the SIVmac239 envelope glycoproteins to mediate virus entry and cell-to-cell fusion. Thus, distantly related immunodeficiency viruses such as SIV and the primary human immunodeficiency virus type 1 isolates can utilize CCR5 as an entry cofactor.

gp120-independent fusion mediated by the human immunodeficiency virus type 1 gp41 envelope glycoprotein: a reassessment

In a natural context, membrane fusion mediated by the human immunodeficiency virus type 1 (HIV-1) envelope glycoproteins involves both the exterior envelope glycoprotein (gp120) and the transmembrane glycoprotein (gp41). Perez et al. (J. Virol. 66:4134-4143, 1992) reported that a mutant HIV-1 envelope glycoprotein containing only the signal peptide and carboxyl terminus of the gp120 exterior glycoprotein fused to the complete gp41 glycoprotein was properly cleaved and that the resultant gp41 glycoprotein was able to induce the fusion of even CD4-negative cells. In the studies reported herein, mutant proteins identical or similar to those studied by Perez et al. lacked detectable cell fusion activity. The proteolytic processing of these proteins was very inefficient, and one processed product identified by Perez et al. as the authentic gp41 glycoprotein was shown to contain carboxyl-terminal gp120 sequences. Furthermore, no fusion activity was observed for gp41 glycoproteins exposed after shedding of the gp120 glycoprotein by soluble CD4. Thus, evidence supporting a gp120-independent cell fusion activity for the HIV-1 gp41 glycoprotein is currently lacking.

Dispensable role of the human immunodeficiency virus type 2 Vpx protein in viral replication

Human immunodeficiency virus type 2 (HIV-2) is similar in genetic organization to HIV-1 but contains a unique gene (vpx) that encodes a 16-kDa protein. A replication-competent molecular clone of HIV-2 (HIV-2sbl/isy) that infects human primary cells in vitro and rhesus monkeys was used to generate three mutations in the vpx gene. In the first mutant, the vpx open reading frame was truncated at amino acid 20; the second mutant was tailored to eliminate the proline-rich carboxyl terminus of the protein; and the third mutant was obtained by addition of four amino acids (KDEL) to the carboxyl terminus of the protein to provide a retention signal in the endoplasmic reticulum. The viral infection kinetics of the three mutant viruses and isogeneic HIV-2sbl/isy in the SupT1 cell line were similar. Slight impairment in the early phases of viral replication was observed during infection of primary human peripheral blood mononuclear cells with the vpx mutant viruses. All of the vpx mutant viruses readily infected macrophages, indicating that vpx expression is dispensable for HIV-2 infection and replication in human macrophages.

The human immunodeficiency virus type 2 vpr gene is essential for productive infection of human macrophages

The human immunodeficiency virus (HIV) genetic determinant(s) responsible for tropism in human T cells or macrophages are not well defined. We studied the role of the HIV type 2 (HIV-2) nef and vpr genes in viral tropism. HIV-2 mutants, lacking either vpr or nef genes, or both vpr and nef, were obtained by site-specific mutagenesis of a biologically active HIV-2 proviral clone (HIV-2sbl/isy), which is infectious in both human T cells and macrophages. Viral progeny carrying mutations of nef, vpr, or of both nef and vpr genes replicated more efficiently than the parental virus in primary human peripheral blood cells and in the human Hut 78 T-cell line. In contrast, the HIV-2 nef- mutant infected human macrophages as efficiently as the parental virus, whereas viruses lacking the vpr gene either alone or in conjunction with the lack of the nef gene did not replicate in macrophages. Thus, some lack of nef in HIV-2 enhances viral replication in T cells and does not interfere with viral replication in primary macrophages, whereas vpr is essential for replication of HIV-2 in human macrophages. Because the parental HIV-2sbl/isy cloned virus also infects rhesus macaques, the use in animal studies of these HIV-2 mutants with differences in cell tropism and rates of replication will be highly useful in understanding the mechanism of viral infectivity and possibly pathogenicity in vivo.

Immunomodulatory properties and toxicity of interleukin 2 in patients with cancer

We performed a phase Ia/Ib study of interleukin 2 (IL2) in patients with cancer. Single doses of IL2 from 10(3) units/m2 to 10(7) units/m2 were well tolerated but failed to induce significant immunological changes. Chronic IL2 treatment for 5 days out of 7 for 3 weeks was well tolerated at doses below 10(7) units/m2 and was accompanied by significant immunological changes. Following chronic treatment with intramuscular injections of IL2 at 1 x 10(6) units/m2, we observed augmentation of peripheral blood natural killer activity and induction of peripheral blood LAK activity. Induction of LAK activity was most evident when IL2 was included in the cytotoxicity assay. There was a marked increase in the number of peripheral blood mononuclear cells bearing the Leu-19 marker in association with the observed increases in natural killer and LAK activity. A small percentage of Leu-19+ cells coexpressed CD3. There was heterogeneous expression of the low affinity Fc receptor (CD16). In vivo induced Leu-19+ cells could be divided into two populations, dim and bright, based on the intensity of fluorescent staining with antibodies to Leu-19. The majority of Leu-19 bright cells were CD16- while the majority of Leu-19 dim cells were CD16+. In addition, the intensity of CD16 staining was higher for Leu-19 dim cells than for Leu-19 bright cells. Increases in the amounts of CD38 and CD8 antigens were also observed. Significant increases in serum levels of the soluble IL2 receptor were observed during treatment. One partial remission was noted in a woman with non-Hodgkin's lymphoma.

In vivo T cell preactivation in chronic uremic hemodialyzed and non-hemodialyzed patients

The production and targeting of a major T cell derived lymphokine, Interleukin 2 (IL-2), were studied in 23 uremic patients undergoing regular hemodialysis treatment and 20 uremic patients prior to the onset of renal replacement therapy. In hemodialyzed patients, abnormally increased proportions of circulating T cells spontaneously expressing high affinity IL-2 receptors (IL-2 Rec) were detected: they bound a monoclonal antibody specifically directed to the IL-2 Rec 55 kDa chain (Tac antigen) (mean +/- SEM: 7.12 +/- 0.81% in patients vs. 2.15 +/- 0.39% in normal controls, P less than 0.0001) and significantly proliferated in presence of human recombinant IL-2 alone (mean +/- SEM: 5438 +/- 729 cpm in patients vs. 1647 +/- 244 cpm in normal controls). Hemodialyzed patients also exhibited significantly increased serum levels of soluble IL-2 receptor (mean +/- SEM: 4036 +/- 947 U/ml in patients vs. 253 +/- 29 U/ml in normal controls. P less than 0.001). Moreover, a significantly decreased IL-2 activity was detected in the supernatants of stimulated T cells from hemodialyzed patients (mean +/- SEM: 0.93 +/- 0.12 U/ml in patients vs. 2.49 +/- 0.22 U/ml in normal controls, P less than 0.0001). In nine hemodialyzed patients who were analyzed before and immediately after the hemodialysis session no acute modifications of the various parameters analyzed were detected. Although less profound, a similar pattern of T cell abnormalities was observed in the uremic non-hemodialyzed patients studied.(ABSTRACT TRUNCATED AT 250 WORDS)

Elevated serum levels of soluble Tac peptide in adult T-cell leukemia: correlation with clinical status during chemotherapy

Adult T-cell leukemia associated with human T-cell leukemia virus type I (HTLV-I) is characterized by a clonal expansion of a CD4-positive subset of T lymphocytes that constitutively express high numbers of interleukin-2 receptors and that frequently infiltrate the skin; osteolytic bone lesions, and hypercalcemia. Using an enzyme-linked immunosorbent assay (ELISA) test, we measured the level of soluble Tac peptide, one chain of the human interleukin-2 receptor, in the serum of 50 patients with adult T-cell leukemia (38 Japanese and 12 American patients), 8 patients with other hematologic malignancies, 8 asymptomatic HTLV-I-antibody-positive carriers, and 17 normal controls. The serum level of soluble Tac peptide (geometric mean U/mL, 95% CI) was elevated at presentation in all patients with adult T-cell leukemia (16,461; 819 to 330,896) when compared with normal controls (238; 112 to 502), patients with other hematologic malignancies (1302; 475 to 3569), and healthy HTLV-I antibody-positive carriers (490; 115 to 2086). The highest levels were seen in patients (n = 33) with acute (32,154; 2587 to 399,598) compared with chronic (5464; 661 to 45,156) disease (n = 14). Serum levels of Tac peptide also tended to be more elevated in patients with adult T-cell leukemia with hypercalcemia (32,072; 2461 to 417,908) compared with normocalcemic patients (13,885; 496 to 388,436). Serial measurements of soluble Tac peptide levels in serum were done in four patients with adult T-cell leukemia during chemotherapy and the levels reflected disease activity. These observations suggest that the measurement of soluble Tac peptide levels in patients with adult T-cell leukemia is useful as a noninvasive measure of tumor burden and will help in the diagnosis of the disease and management of these patients.

Soluble Tac peptide is present in the urine of normal individuals and at elevated levels in patients with adult T cell leukaemia (ATL)

The T lymphocyte-derived lymphokine interleukin 2 and the cell-associated receptor for this molecule play major roles in the activation and regulation of the human immune response. An enzyme-linked immunosorbent assay has been developed to measure quantitatively a soluble form of one component of the human interleukin 2 receptor, namely the Tac peptide. In the present studies, soluble Tac peptide was measured in the urine of normal individuals (mean = 92 U/ml), a level not significantly different (0.01 less than P less than 0.05) from the corresponding serum concentrations (mean = 175). The urinary Tac peptide had a molecular weight of 40-45 kD by sodium dodecyl sulphate-polyacrylamide gel electrophoresis analysis and specifically bound interleukin 2. Elevated levels of urinary Tac peptide were found in four patients with adult T cell leukaemia who also had elevated serum levels of Tac peptide. Thus, urine may represent a valuable source of lymphokine-binding proteins that may serve as important markers of immunological activation.

Serum soluble IL-2 receptor as a tumor marker in patients with hairy cell leukemia

Activated T cells synthesize and express a cell membrane-bound receptor for interleukin-2 (IL-2) and have recently been shown to secrete a soluble form of the same receptor. Hairy cell leukemia is a chronic disorder caused by expansion of a clonal population of an unusual mononuclear cell of B cell origin. These cells have previously been shown to express an IL-2 receptor on the cell membrane. The sera of 26 patients with hairy cell leukemia were examined for the presence of a soluble IL-2 receptor before and during therapy with either recombinant interferon alpha-2a or 2'-deoxycoformycin. Before therapy, all patients had markedly elevated levels of this soluble IL-2 receptor ranging from five to 60 times the highest level observed in normal control sera. In individual patients changes in the level during therapy correlated well with clinical assessments of tumor response; levels fell to near the normal range in patients responding to therapy. Patients not responding to interferon alpha had no significant change in the soluble IL-2 receptor level. These results suggest that hairy cells secrete a soluble IL-2 receptor and that serial measurements of the level of this receptor in the serum can be used as a noninvasive means to assess disease response to therapy.

Elevated concentrations of soluble interleukin-2 receptors in serum samples and bronchoalveolar lavage fluids in active sarcoidosis

Sarcoidosis is a granulomatous disorder of unknown cause characterized by activation of T-lymphocytes. We here report the use of an enzyme-linked immunosorbent assay for the soluble interleukin-2 receptor (IL-2R) as a measure of T-cell activation in serum samples and bronchoalveolar lavage fluids in 15 patients with active sarcoidosis. The geometric mean (x divided by SEM) value for soluble IL-2R in serum samples from patients with sarcoidosis was 1,110 (x divided by 1.17) versus 224 (x divided by 1.08) U/ml for normal control subjects (p less than 0.001). Detectable levels of soluble IL-2R were present in bronchoalveolar lavage fluids from 10 of 15 patients with sarcoidosis versus only 2 of 36 normal control subjects (p less than 0.001). Levels of soluble IL-2R in serum samples from untreated patients with sarcoidosis correlated with 67gallium lung scanning scores (p less than 0.05) but not with serum angiotensin-converting enzyme concentrations or constituents of bronchoalveolar lavage. In 5 patients, the level of soluble IL-2R in serum samples fell from 1,499 (x divided by 1.20) to 476 (x divided by 1.58) U/ml (p less than 0.05) after 6 wk of successful treatment with corticosteroids, whereas the changes in soluble IL-2R in bronchoalveolar lavage fluids were more variable. These observations suggest that measurements of soluble IL-2R, particularly in serum samples, may reflect disease activity and be clinically useful in the management of patients with sarcoidosis.

A competitive enzyme-linked immunoassay (ELISA) for the measurement of soluble human interleukin-2 receptors (IL-2R, Tac protein)

A solid-phase, competition enzyme-linked immunosorbent assay (ELISA) was established for the quantitative measurement of soluble (human) interleukin-2 receptors (IL-2R). The ladder of reagents from the solid phase up consisted of: (1) recombinant DNA-derived, purified IL-2R, (2) sample-containing soluble IL-2R and fluorescein isothiocyanate (FITC)-conjugated monoclonal antibody, 7G7/B6, directed against the IL-2R, (3) alkaline phosphatase-conjugated rabbit anti-FITC, and (4) substrate. This ELISA was compared with a 'sandwich' ELISA for soluble IL-2R. The competitive ELISA was less sensitive than the 'sandwich' assay, being capable of measuring 5000 versus 31 U/ml, respectively. While both anti-Tac and 7G7/B6 in the IL-2R-containing sample inhibited the 'sandwich' assay, only 7G7/B6 inhibited the competition assay. Anti-mouse immunoglobulin enhanced the 'sandwich' assay and inhibited the competitive assay; both effects could be overcome by the addition of normal mouse immunoglobulin in the sample buffer. Studies of a patient's serum receiving anti-Tac as therapy for the adult T cell leukemia demonstrated that rises in the level of IL-2R occurring with anti-Tac therapy, as measured with the competition assay, were masked in the 'sandwich' assay. This competition ELISA will be useful for measuring soluble IL-2R levels in patients receiving anti-Tac as therapy for various immunologic disorders.

Projections from the reticular formation of the medulla, the spinal trigeminal and lateral reticular nuclei to the inferior olive

Injections of tritiated L-leucine were placed in the reticular formation of the medulla, the spinal trigeminal and lateral reticular nuclei of cats and silver grain accumulations in the inferior olivary nucleus were demonstrated by autoradiography. Cells of the reticular formation located at the junction of nuclei reticularis magnocellularis and reticularis parvocellularis in the rostral medulla and within nucleus reticularis ventralis in the caudal medulla contribute four distinct projections to the olive. Three projections are distributed ipsilaterally in the caudal part of the medial accessory olive, at mid-level of the dorsal accessory olive and in the ventrolateral bend of the principal olive, at rostral levels. There is also a small controlateral projection to the caudal part of the medial accessory olive. the spinal trigeminal nucleus sends crossed projections to the rostral part of the dorsal accessory olive and adjacent ventral lamella as well as to the caudal part of the medial accessory olive. The lateral reticular nucleus sends an extensive ipsilateral projection to the caudal part of the medial accessory olive and provides a small contribution to the same subdivision, contralaterally. All these projections converge with other known afferents to the olive.