Horseradish Peroxidase Complex Research Articles

The recent research progress in neurobiological characteristics and pain regulation of the cerebrospinal fluid-contacting nucleus

AbstractThe ependymal epithelium forms the cerebrospinal fluid barrier, separating the brain and spinal cord from the cerebrospinal fluid. However, in specific regions of the central nervous system, there are neurons that directly interface with the cerebrospinal fluid, including neuronal bodies, dendrites, or axons, This constitutes what is referred to as the "cerebrospinal fluid contacting neurons system (CSF-CNS)". The research team led by Professor Zhang has successfully utilized cholera toxin subunit B coupled horseradish peroxidase complex (CB-HRP) to selectively label the specialized neuron system that interfaces with cerebrospinal fluid, pioneeringly designating it as the "cerebrospinal fluid-contacting nucleus", commonly referred to as the "CSF-contacting nucleus". For the first time, the discovery of the CSF-contacting nucleus provides compelling morphological evidence for the existence of a distinct neural structure within the brain parenchyma that establishes a connection with the cerebrospinal fluid, thereby suggesting its potential significance in facilitating material and information exchange between the brain parenchyma and cerebrospinal fluid. After conducting a comprehensive series of studies on the morphological structure, material expression, gene analysis and functional aspects of the CSF-contacting nucleus in rodents and non-human primates, it has been revealed that there are fibrous connections between the CSF-contacting nucleus and the cerebral cortex and subcortical nuclei being involved in the regulatory mechanisms of pain, cognition, learning and memory, emotion, addiction, stress and anxiety responses, visceral activity, olfaction, vision processing and perception, auditory processing, perception, motor control and coordination, homeostasis regulation including maintenance of body energy and fluid balance, as well as the control of sleep–wake cycles and synchronization of biological rhythms. Current experiments have confirmed that the CSF-contacting nucleus is related to pain, morphine dependence and withdrawal, learning and memory, as well as stress. This present article offers a comprehensive review of the neurobiological characteristics and recent advancements in pain regulation of the CSF-contacting nucleus. The aim is to provide novel insights into the investigation of pain regulation within bidirectional regulatory pathway between the brain and cerebrospinal fluid, with a specific focus on elucidating the role of the CSF-contacting nucleus as a bridge structure. Additionally, the objective of this research is to propose innovative strategies for pain management and associated disorders in the future.

Dopamine as a polymerizable reagent for enzyme-linked immunosorbent assay using horseradish peroxidase

We demonstrate that dopamine can be used as a reagent for colorimetric enzyme-linked immunosorbent assay (ELISA) using horseradish peroxidase (HRP). Dopamine was able to be polymerized in the presence of HRP and H2O2, and black polydopamine was obtained after the enzymatic reaction. Because of the black color, the absorbance was significantly changed in the whole range of the visible light region. Here, an indirect competitive ELISA based on the polymerization of dopamine was performed to detect a fluoroquinolone antibiotic, enrofloxacin. The antibiotic is commonly used in livestock farming. The anti-antibiotics antibody was produced from egg yolk from chicken hens. In the visible range, sufficient absorbance changes of ∼0.4∼0.5 and a low background level for the ELISA response were obtained, and the 50 % inhibitory concentration value at 450 nm was determined to be 26 ppb. The performance of the indirect competitive ELISA based on the polymerization of dopamine was compared to that based on the oxidation of catechol because dopamine has a catechol skeleton. By the complex of HRP and H2O2, catechol can be oxidized to o-benzoquinone having a maximum absorption wavelength of 420 nm. It was shown that the absorbance change in the case of polydopamine was about 2.5 times higher than that of catechol, where the background levels were similar. This confirms that the polymerization of dopamine significantly enhanced the photosignal.

Differences in the distribution of CD20, CD3, CD34 and CD45RO in nasal mucosa and polyps from patients with chronic rhinosinusitis.

The present study focused on the assessment of the inflammatory infiltrate that characterizes nasal polyps in patients with chronic rhinosinusitis and nasal polyposis. Inflammatory cell type was determined using specific markers. This evaluation was made possible by determining the expression of the following markers: CD20, a marker of B lymphocytes [using activated T cells (ATC) armed with CD20 antibody]; CD3, a marker of T lymphocytes (using ATC armed with anti-CD3 antibody); CD45, the leukocyte common antigen (using ATC armed with anti-CD45 antibody; and CD34, for the microvasculature of the nasal polyp (using anti-CD34 antibody). The diagnosis of chronic rhinosinusitis with nasal polyps (CRSwNP) was made according to current EPOS guidelines based on patient history, clinical examination and nasal endoscopy. We examined surgically resected nasal polyps from 127 patients diagnosed with CRSwNP, who benefited from surgical procedures at the Department of Otorhinolaryngology of our institution. The polyps were analyzed at the Department of Pathology of our institution utilizing histopathological and immunohistochemical methods as follows: Firstly, the tissues were paraffin-impregnated, sectioned and stained with hematoxylin and eosin. We then examined the expression of CD3, CD20, CD34 and CD45RO by immunohistochemistry with soluble labeled streptavidin biotin (LSAB)/horseradish peroxidase (HRP) complexes. We observed the following histopathological changes: The structure of the epithelium was evidenced by collagenous subjacent stroma with mixed areas, sometimes associated with hyaline zones. In all types of polyps, we also observed a diffuse underlayer or periglandular lymphoplasmacytic in filtrate composed predominantly from T lymphocytes and eosinophils. The histopathological changes suggest the chronic inflammation of the sinus mucosa, which was diffusely distributed in allergic polyps and with nodular distribution in fibro-inflammatory polyps. The number of B lymphocytes was greater in the fibro-inflammatory polyps. On the whole, the findings of this study indicate that the inflammatory infiltrate in nasal polyps from patients with CRSwNP is mainly composed of T cells and eosinophils in all types of polyposis. In addition, a diffuse distribution of allergic polyps and the nodular distribution of fibro-inflammatory polyps, and the hyperplasia of the seromucous glands was observed. The determination of CD20, CD3, CD34 and CD45RO could be used to assess the inflammatory infiltrate of the nasal poplyps in these patients.

91 Expression Pattern of Neuron-Specific Red Fluorescence Protein in Nervous System of Transgenic Dog with Human Synapsin I Promoter

Neurodegenerative disorders, such as Alzheimer’s disease, affect neurons in large areas within the central nervous system. The selective expression of disease-causing and therapeutic genes in susceptible regions and cell types is critical to the generation of animal models. In our previous studies, we reported production of a transgenic dog by nuclear transfer using donor cells that had been stably transfected by vector containing the red fluorescence protein (RFP) and human synapsin I (SynI) promoter, a neuron-specific promoter. Here, we evaluated whether RFP expression in transgenic dog with SynI (SynI dog) had high neuronal specificity and strong transcriptional activity. For confirmation of neuron-specific RFP expression, tissue samples were obtained from a killed 4-year-old SynI dog. Quantification of RFP in heart, kidney, liver, lung, spleen, cerebrum, cerebrum, cerebellum, midbrain, hippocampus, peripheral nerves, skin, and spinal cord of SynI dog was analysed using ELISA (Cell Biolabs, San Diego, CA, USA). Moreover, the distribution of RFP activity in neural system of the SynI dog was determined by immunohistochemistry. The first antibody, rabbit polyclonal RFP antibody (1:200, ab62341, Abcam, Cambridge, MA, USA) was applied, and antibody labelling was visualised by incubation with avidin-biotinylated horseradish peroxidase complex (1:1,000; ABC Elite, Vector Laboratories, Burlingame, CA, USA). In the 4-year-old SynI dog, RFP was observed only in neuronal tissues including brain, spinal cord, and peripheral nerves, but was not detected in non-neuronal tissue such as heart, kidney, and skin. In addition, robust RFP expression was observed in the neurons of the peripheral nerve, spinal cord, and prefrontal cortex. In the hippocampus and cerebellum, the RFP-expressing cells appeared heterogeneous in hippocampus neurons and purkinje cells. In conclusion, we report that human SynI promoter is functional in neural cells of dogs. A neural specific-transgene expressed dog could be applied as a research tool in the study of neurodegenerative disorders. This research was supported by RDA (#PJ010928032017), Korea IPET (#316002-05-2-SB010), NRF (#2016R1D1A1B03932198), and Research Institute for Veterinary Science, the BK21 plus program.

A rapid and visual turn-off sensor for detecting copper (II) ion based on DNAzyme coupled with HCR-based HRP concatemers

To solve the requirement of on-site, rapid, and visual detection of copper (II) (Cu2+) in aqueous solution, a turn-off sensor for detecting copper (II) ion was developed based on Cu2+-dependent DNAzyme as the recognition element and hybridization chain reaction (HCR)-based horseradish peroxidase (HRP) concatemers as the signal amplifier and the signal report element. The detection unit, which was composed of the immobilized Cu2+-dependent DNAzyme coupled with HCR-based HRP concatemers via Waston-Crick base pairing, could catalyze hydrogen peroxide (H2O2) via TMB, generating obvious green color and turning yellow after sulfuric acid termination with optical absorption at 450 nm. Upon Cu2+ addition, the substrate strand of the Cu2+-dependent DNAzyme concatenated with the HCR-based HRP complex was irreversibly cleaved, efficiently causing dramatic reduction of the detection signal. Under optimal conditions, the detection signal decreased with the concentration of Cu2+ in 5 min, exhibiting a linear calibration from 0.05 to 3 μM with a detection limit of 8 nM. The sensor also displayed a high selectivity for Cu2+ given the specificity and anti-interference of the detection unit, and this system was applicable for monitoring Cu2+ in real water samples. Generally speaking, the proposed sensor exhibits good potential in environment surveys.

Downregulation of glutathione transferase π sensitizes lymphoma/leukaemia cells to platinum‐based chemotherapy

Downregulation of glutathione transferase π sensitizes lymphoma/leukaemia cells to platinum‐based chemotherapy

Comparison of monomeric and polymeric horseradish peroxidase as labels in competitive ELISA for small molecule detection

We have developed a simple and sensitive com- petitive enzyme-linked immunosorbent assay (ELISA) to determine aflatoxin B1 (as a model small analyte) and using streptavidin-polymeric horseradish peroxidase complex (SApolyHRP) as a label for signal amplification. The per- formance of the assay was evaluated by comparing it with the classical indirect competitive ELISA using HRP labeled anti-mouse IgG as the tracer antibody. The results indicate that the SApolyHRP-based competitive ELISA exhibits a typically 2.4-fold steeper slope of the linear working range of the calibration curve compared to the monomeric HRP based classical ELISA, i.e., the sensitivity was increased. The SApolyHRP conjugate causes a typically 19-fold stron- ger signal generation in comparison to the traditional HRP labeled anti-mouse IgG at the same concentration (25 ng mL �1 ). Moreover, the SApolyHRP-based assay has a much wider linear range and a 3.8-fold better signal-to- noise ratio. Considering its simplicity, sensitivity and ease of operation, this competitive ELISA is considered to be a promising tool for small molecule immunodetection.

Immunolocalization of Progesterone Receptors in the Canine Oviduct around Ovulation

In the bitch, oocyte maturation, sperm storage, fertilization and early embryo development take place within the oviducts under high and increasing circulating progesterone concentrations. To investigate the potential effects of progesterone on the canine oviduct, nuclear progesterone receptors (PR) were localized. Oviducts were collected by ovariectomy from adult Beagle bitches during anestrus, after the onset of proestrus but prior to the Luteinizing Hormone (LH) peak (Pre-LH), after the LH peak but before ovulation (Pre-ov) and on Days 1, 4 and 7 after ovulation (n = 3 bitches per stage). The cellular distribution of PR was studied by immunohistochemistry (IHC) in the ampulla, isthmus and tubal part of the utero-tubal junction (UTJ). Plasma progesterone and 17β-oestradiol were assayed on the day of surgery. PR were specifically expressed in the nuclei of epithelial, stromal and muscular cells in the ampulla, isthmus and UTJ. The IHC scores did not vary from one oviductal region to another. However, the epithelium displayed higher scores than the stroma at anestrus, Pre-ov, Days 4 and 7, and also higher scores than muscle at Days 4 and 7 (p < 0.05). Immunohistochemistry scores in the stroma and muscle decreased at Days 4 and 7 compared with previous stages (p < 0.05). Furthermore, muscular IHC scores were positively correlated with circulating 17β-oestradiol concentrations and negatively correlated with circulating progesterone concentrations (p < 0.05). In conclusion, PR were identified in the canine oviduct, with differences in expression between tissues and times around ovulation, suggesting that progesterone may regulate tubal functions and reproductive events in this species.

Deficiency of Growth Factor Midkine Exacerbates Necrotizing Glomerular Injuries in Progressive Glomerulonephritis

Inflammatory cell infiltration and fibrin deposition play important roles in the development of crescentic glomerulonephritis (GN). In particular, activation of coagulation is an indispensable factor in crescent formation. However, the mechanisms underlying the pathogenesis of crescent formation have not been completely elucidated. We identified the growth factor midkine (MK) as a novel key molecule in the progression of crescentic GN induced by anti-glomerular basement membrane antibody. Despite the lack of significant differences in autologous and heterologous reactions, MK-deficient (Mdk(-/-)) mice unexpectedly showed a greater number of necrotizing glomerular injuries than wild-type (Mdk(+/+)) mice. Likewise, more tubulointerstitial damage was observed in Mdk(-/-) mice, and this damage positively correlated with glomerular injury. Plasminogen activator inhibitor (PAI)-1 was strongly induced in the injured glomerulus of Mdk(-/-) mice, particularly in crescents and endothelial cells. This enhanced PAI-1 production was associated with an increase in inflammatory cell infiltration and matrix deposition in the glomerulus and the interstitium of Mdk(-/-) mice. In line with these invivo data, primary cultured endothelial cells derived from Mdk(-/-) mice exhibited higher PAI-1 mRNA expression on fibrin challenge and less fibrinolysis than Mdk(+/+) mice. In contrast, the expression of plasminogen activators was not affected. Our combined data suggest that MK leads to a blockade of PAI-1, which is closely associated with the suppression of crescentic GN.

Neurogliaform cells of amygdala: a source of slow phasic inhibition in the basolateral complex

Synaptic inhibition in the amygdala actively participates in processing emotional information. To improve the understanding of interneurons in amygdala networks it is necessary to characterize the GABAergic cell types, their connectivity and physiological roles. We used a mouse line expressing a green fluorescent protein (GFP) under the neuropeptide Y (NPY) promoter. Paired recordings between presynaptic NPY-GFP-expressing (+) cells and postsynaptic principal neurons (PNs) of the basolateral amygdala (BLA) were performed. The NPY-GFP+ neurons displayed small somata and short dendrites embedded in a cloud of highly arborized axon, suggesting a neurogliaform cell (NGFC) type. We discovered that a NPY-GFP+ cell evoked a GABA(A) receptor-mediated slow inhibitory postsynaptic current (IPSC) in a PN and an autaptic IPSC. The slow kinetics of these IPSCs was likely caused by the low concentration and spillover of extracellular GABA. We also report that NGFCs of the BLA fired action potentials phase-locked to hippocampal theta oscillations in anaesthetized rats. When this firing was re-played in NPY+-NGFCs in vitro, it evoked a transient depression of the IPSCs. Presynaptic GABA(B) receptors and functional depletion of synaptic vesicles determined this short-term plasticity. Synaptic contacts made by recorded NGFCs showed close appositions, and rarely identifiable classical synaptic structures. Thus, we report here a novel interneuron type of the amygdala that generates volume transmission of GABA. The peculiar functional mode of NGFCs makes them unique amongst all GABAergic cell types of the amygdala identified so far.

Self‐Assembled Complexes of Horseradish Peroxidase with Magnetic Nanoparticles Showing Enhanced Peroxidase Activity

AbstractBio‐nanocatalysts (BNCs) consisting of horseradish peroxidase (HRP) self‐assembled with magnetic nanoparticles (MNPs) enhance enzymatic activity due to the faster turnover and lower inhibition of the enzyme. The size and magnetization of the MNPs affect the formation of the BNCs, and ultimately control the activity of the bound enzymes. Smaller MNPs form small clusters with a low affinity for the HRP. While the turnover for the bound fraction is drastically increased, there is no difference in the H2O2 inhibitory concentration. Larger MNPs with a higher magnetization aggregate in larger clusters and have a higher affinity for the enzyme and a lower substrate inhibition. All of the BNCs are more active than the free enzyme or the MNPs (BNCs &gt; HRP ≫ MNPs). Since the BNCs show surprising resilience in various reaction conditions, they may pave the way towards new hybrid biocatalysts with increased activities and unique catalytic properties for magnetosensitive enzymatic reactions.

Acidic Fibroblast Growth Factor (FGF) Potentiates Glial-mediated Neurotoxicity by Activating FGFR2 IIIb Protein

Previous studies indicate that astrocytes are the brain cells that express acidic fibroblast growth factor (aFGF) and that the expression is increased upon activation. However, there has been no study investigating the significance of this phenomenon. Here we report that aFGF treatment of IFNγ-stimulated human astrocytes, and LPS/IFNγ-stimulated human microglia, enhances their secretion of inflammatory cytokines and other materials toxic to human neuroblastoma SH-SY5Y cells. The mechanism of aFGF enhancement involves stimulation of the receptor FGFR2 IIIb. We show by RT-PCR that this receptor, but not other FGF receptors, is robustly expressed by astrocytes and microglia. We establish by Western blotting, and immunohistochemistry on postmortem human brain tissue that the FGFR2 IIIb protein is expressed by both of these glial cell types. We blocked the inflammatory stimulant action of aFGF by transfecting microglia and astrocytes with a small inhibitory RNA (siRNA) to FGFR2 IIIb as well as by removal of aFGF using an anti-aFGF antibody. Treatment with bFGF in combination with the stimulants was without effect, but together with aFGF, it partially counteracted the action of aFGF, indicating that it may be a weak antagonist of FGFR2 IIIb. The inflammatory effect was also attenuated by treatment with inhibitors of protein kinase C, Src tyrosine kinase, and MEK-1/2 indicating the involvement of these intracellular pathways. Our data suggest that inhibition of expression or release of aFGF could have therapeutic potential by inhibiting inflammation in neurodegenerative diseases such as Alzheimer disease where many neuroinflammatory molecules are prominently expressed.

ApoA-I deficiency in mice is associated with redistribution of apoA-II and aggravated AApoAII amyloidosis

Apolipoprotein A-II (apoA-II) is the second major apolipoprotein following apolipoprotein A-I (apoA-I) in HDL. ApoA-II has multiple physiological functions and can form senile amyloid fibrils (AApoAII) in mice. Most circulating apoA-II is present in lipoprotein A-I/A-II. To study the influence of apoA-I on apoA-II and AApoAII amyloidosis, apoA-I-deficient (C57BL/6J.Apoa1⁻/⁻) mice were used. Apoa1⁻/⁻ mice showed the expected significant reduction in total cholesterol (TC), HDL cholesterol (HDL-C), and triglyceride (TG) plasma levels. Unexpectedly, we found that apoA-I deficiency led to redistribution of apoA-II in HDL and an age-related increase in apoA-II levels, accompanied by larger HDL particle size and an age-related increase in TC, HDL-C, and TG. Aggravated AApoAII amyloidosis was induced in Apoa1⁻/⁻ mice systemically, especially in the heart. These results indicate that apoA-I plays key roles in maintaining apoA-II distribution and HDL particle size. Furthermore, apoA-II redistribution may be the main reason for aggravated AApoAII amyloidosis in Apoa1⁻/⁻ mice. These results may shed new light on the relationship between apoA-I and apoA-II as well as provide new information concerning amyloidosis mechanism and therapy.

Ultrasensitive electrochemical strategy for NT-proBNP detection with gold nanochains and horseradish peroxidase complex amplification

A novel electrochemical immunosensor for sensitive detection of cardiac biomarker N-terminal pro-B-type natriuretic peptide (NT-proBNP) is fabricated based on the nanostructural gold and carbon nanotubes composite as desirable platform for the capture antibodies immobilization and gold nanochains (AuNCs) and horseradish peroxidase (HRP) complex labeled secondary antibodies (AuNCs-HRP-Ab 2) for signal amplification. The gold nanochains were prepared by the employment of l-ascorbic acid (AA) as a mediator and template. With the surface area enhancement by nanostructural gold functionalized carbon nanotubes composite, the amount of immobilized primary antibodies (Ab 1) can be enhanced. More importantly, enhanced sensitivity can be achieved by introducing the multibioconjugates of AuNCs-HRP-Ab 2 onto the electrode surface through “sandwich” immunoreactions. The linear range extended from 0.02 to 100 ng/mL with a correlation coefficient of R = 0.997 and a limit of detection reaching 6 pg/mL at a signal-to-noise ratio of 3:1, which is well below the commonly accepted concentration threshold (0.1 ng/mL) used in clinical diagnosis. The specificity, regeneration and stability test demonstrated the feasibility of the developed immunoassay, which gives the attractive characteristics to be a candidate for the detection of NT-proBNP and other proteins of interest in both fundamental and applied research.

Choline Acetyltransferase Staining in Brain Sections

INTRODUCTIONThis protocol describes the use of immunocytochemical methods to stain for choline acetyltransferase (ChAT). The avidin-biotin horseradish peroxidase complex (ABC) triple-labeling method used here takes advantage of the extraordinary affinity between avidin and biotin. Horseradish peroxidase attached to biotin in the complex is developed using diaminobenzidine (DAB).

Direct electrochemistry and electrocatalysis of complex of horseradish peroxidase and La(III) at nano-gold colloid/cysteine/gold electrode

In this paper, the measurement results of sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE), matrix-assisted laser desorption/ionization time-of-flight mass (MALDI–TOF/MS) spectroscopy and inductively coupled plasma mass spectrometry (ICP-MS) demonstrated that the complex of horseradish peroxidase (HRP) and La(III) (La–HRP) can be formed in horseradish in vivo after horseradish is treated with 80 μM La(III). The electrochemical measurements further demonstrated that the direct electrochemical performance and the bioelectrocatalytic activity of the La–HRP complex are worse than that of HRP. This means that when HRP is treated with the high concentration of La(III), the natural function of HRP is inhibited due to the change in the structure of HRP. Thus, it would be harmful for horseradish and other organisms. This result would provide some references for better understanding the toxicity mechanism of rare earth elements and heavy metals in the organisms.

A sandwich enzyme-linked immunosorbent assay for adducts of polycyclic aromatic hydrocarbons with human serum albumin

Adducts of benzo[ a]pyrene-diolepoxide (BPDE) with blood nucleophiles have been used as biomarkers of exposure to polycyclic aromatic hydrocarbons (PAHs). The most popular such assay is a competitive enzyme-linked immunosorbent assay (ELISA) that employs monoclonal antibody 8E11 to detect benzo[ a]pyrene tetrols following hydrolysis of BPDE adducts from lymphocyte DNA or human serum albumin (HSA). Here we used 8E11 as the capture antibody in a sandwich ELISA to detect BPDE–HSA adducts directly in 1-mg samples of HSA or 20 μl of serum/plasma. The assay employs an anti-HSA antibody for detection, and this is amplified by an avidin/biotinylated horseradish peroxidase complex. The sandwich ELISA has advantages of specificity and simplicity and is approximately 10 times more sensitive than the competitive ELISA. To validate the assay, HSA samples were assayed from three populations with known high PAH exposures (coke oven workers), medium PAH exposures (steel factory control workers), and low PAH exposures (volunteer subjects) ( n = 30). The respective geometric mean levels of BPDE–HSA adducts—67.8, 14.7, and 1.93 ng/mg HSA (1010, 220, and 28.9 fmol BPDE equiv/mg HSA)—were significantly different ( P < 0.05). The sandwich ELISA will be useful for screening PAH exposures in large epidemiologic studies and can be extended to other adducts for which capture antibodies are available.

In situ characterization of the foam cells in early human atherosclerotic lesions.

Erythrocytes (E) sensitized with IgG antibodies bound to the fatty streaks in cryostat sections of early human atherosclerotic lesions. E sensitized with IgA or IgM antibodies of F(ab') 2 fragments of IgG did not bind. The binding was inhibited by intact IgG and by Fc fragments but not by F (ab')2 fragments or by albumin, indicating the presence of receptors for the Fc part of IgG (FcR). E sensitized with IgM antibodies and human complement did not bind. The FcR were also studied using soluble immune complexes of horseradish peroxidase (HRP) and rabbit IgG antibodies to HRP. The peroxidase activity was detected histochemically. The bound complexes were localized to most of the lipid cells (foam cells) in the lesions. The cytoplasm of the FcR positive foam cells stained diffusely for acid alpha- naphthyl acetate esterase. Most of the foam cells were stained with monoclonal antibodies against HLA-DR antigens. The data indicate that most foam cells in early atherosclerotic lesions are derived from monocytes.

Activation of mTORC1 Signaling Pathway in AIDS-Related Lymphomas

Using immunohistochemistry with antibodies against the phosphoserine residues in both S6rp and 4E binding protein 1, we identified the activation of the mammalian target of rapamycin (mTORC)1 pathway in 29 cases of AIDS-related lymphoma. These cases represented a diverse spectrum of histological types of non-Hodgkin lymphoma (24 cases) and classic Hodgkin lymphoma (five cases). mTORC1 was also activated in the hyperplastic but not involuted follicles of HIV-associated lymphadenopathy in eight cases, supporting the notion that mTORC1 activation is a common feature of transformed lymphocytes irrespective of either their reactive or malignant phenotype. We also found that in B-cell lines that represent diffuse large B-cell lymphoma, Burkitt lymphoma, Epstein-Barr virus-infected lymphocytes, and human herpesvirus 8-positive primary effusion lymphoma, inhibitors of Syk, MEK, and, seemingly, phosphoinositide 3 kinases suppressed mTORC1 activation, in particular when these inhibitors were used in combination. These findings indicate that AIDS-related lymphoma and other histologically similar types of lymphomas that are derived from transformed B lymphocytes may display clinical responses to inhibitors that directly target mTORC1 or, possibly, upstream activators of the mTORC1 pathway.

Direct electrochemistry and spectroelectrochemistry of osmium substituted horseradish peroxidase

In this contribution the substitution of the central protoporphyrin IX iron complex of horseradish peroxidase by the respective osmium porphyrin complex is described. The direct electrochemical reduction of the Os containing horseradish peroxidase (OsHRP) was achieved at ITO and modified glassy carbon electrodes and in combination with spectroscopy revealed the three redox couples Os IIIHRP/Os IVHRP, Os IVHRP/Os VHRP and Os VHRP/Os VIHRP. The midpoint potentials differ dependent on the electrode material used with E 1/2 (Os III/IV) of − 0.4 V (ITO) and − 0.25 V (GC), E 1/2 (Os IV/ V) of − 0.16 V (ITO) and + 0.10 V (GC), and E 1/2 (Os V/VI)of + 0.18 V (ITO), respectively. Moreover, with immobilised OsHRP the direct electrocatalytic reduction of hydrogen peroxide and tert-butyl hydroperoxide was observed. In comparison to electrodes modified with native HRP the sensitivity of the OsHRP-electrode for tert-butyl hydroperoxide is higher.