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- ArticleSağir M, Güven E, Eröz S, Uras C.Medicine (Baltimore). 2023 May 12;102(19):e33758.Direct-to-implant reconstruction is one of the breast repair techniques after mastectomy. Implant selection is critical in the short- and long-term success of direct-to-implant reconstruction after nipple-sparing mastectomy. In this study we developed a 10-step algorithm that we use before and during surgery. We aimed to obtain natural and stable breast reconstruction with this algorithm. In addition, we also aimed to evaluate which implants were selected using this algorithm and their short- and long-term outcomes. This retrospective study included 218 patients aged 27 to 60 years who underwent mastectomy and direct-to-implant reconstruction between November 2018 and December 2021. The patients were assigned into 4 groups according to amount of breast tissue removed. We developed a 10-step algorithm and these included: breast base, amount of breast tissue removed, evaluation of mastectomy skin flap, breast projection, ptosis, unilateral/bilateral reconstruction, chest wall deformity, patient's request, comorbid conditions and stabilization and arrangement of novel sulcus. The evaluation was made when the patient's photographs were taken at least 1 year after the surgery. The highest number of patients was recorded in group 3; in addition, mean age was also highest in group 3. The lowest number of patients was recorded in group 4. The body mass index showed a progressive increase from group 1 to group 4. Medium height moderate profile prosthesis was used in 81.7% while medium height moderate plus profile prosthesis was used in 18.3% of breasts included. We used larger prosthesis up to 58.1% when compared to the tissue removed in group 1 while we used smaller prosthesis by 25.6% in group 4. In the anterior view, the medial and lateral arch of the lower pole of the breast was obtained in all patients. Obvious asymmetry developed in 4 patients. In lateral and oblique views, upper and lower pole natural breast images were obtained in all patients, except for 5 patients. There was no sulcus inferior displacement in any patient. Implant extrusion did not occur in any patient. This algorithm is an easy to use and effective method to obtain a stable and natural breast image in the long-term.
- ArticleHansen K, Albert T, Quinonez J, Ruxmohan S.Cureus. 2023 Jan;15(1):e33758.The standard convention for diagnosing bone fractures is through radiography. However, radiography can miss fractures depending on the type of injury or if human error is present. This may be due to improper patient positioning leading to superimposing bones being captured in the image, obscuring pathology. As of late, ultrasound has been gaining traction in terms of its utilization for diagnosing fractures, which radiography can miss at times. Here we present a case of a 59-year-old female who was diagnosed using ultrasound with an acute fracture that was initially missed on X-ray. We present a case of a 59-year-old female with a past medical history significant for osteoporosis who presented to an outpatient clinic for evaluation of acute left forearm pain. She reported sustaining a mechanical fall forward to the ground three weeks before bracing herself with her forearms, immediately developing left upper extremity pain lateralized to the forearm. Upon initial evaluation, forearm radiographs were obtained and showed no evidence of acute fractures. She then underwent a diagnostic ultrasound that showed an obvious fracture of the proximal radius, distal to the radial head. Upon reviewing initial radiograph films, it was evident that the proximal ulna was superimposed over the radius fracture as a proper neutral anteroposterior view of the forearm was not taken. The patient then underwent a computed tomography (CT) scan of her left upper extremity, which confirmed the presence of a healing fracture. We present a case in which ultrasound is an excellent adjunct when a fracture cannot be identified on plain film radiography. Its utilization should be well-known and considered more often in the outpatient setting.
- ArticleDöppler H, Panayiotou R, Reid EM, Maimo W, Bastea L, Storz P.Sci Rep. 2016 09 21;6:33758.Increased expression of PRKD1 and its gene product protein kinase D1 (PKD1) are linked to oncogenic signaling in pancreatic ductal adenocarcinoma, but a direct functional relationship to oncogenic KRas has not been established so far. We here describe the PRKD1 gene promoter as a target for oncogenic KRas signaling. We demonstrate that KRas-induced activation of the canonical NF-κB pathway is one mechanism of how PRKD1 expression is increased and identify the binding sites for NF-κB in the PRKD1 promoter. Altogether, these results describe a novel mechanism governing PRKD1 gene expression in PDA and provide a functional link between oncogenic KRas, NF-κB and expression of PRKD1.
- ArticleLiu J, Chen Y, Wang W, Hao C, Cai F, Teng L, Luo X.Heliyon. 2024 Jul 15;10(13):e33758.In order to study the influence of ventilation parameters on the ventilation of plateau highway construction tunnels, a highway tunnel construction section in Yunnan is taken as the research background, and Fluent software is used for simulation. The results of the study show that: under the conditions of press-in ventilation, the wind speed in the center of the vortex area in the wind flow field is smaller than the wind speed in the surrounding area, and with the diffusion of the flow field, the average wind speed in the tunnel section gradually decreases, and ultimately stabilizes at the level of 0.5 m/s. After blasting, the dust mass concentration on the return side of the tunnel is higher than that on the duct side. Dust with a particle size of 30 μm or more settled rapidly within 100 m from the boring face, while dust with a particle size of 30 μm or less gradually diffused outward under the action of the wind flow. In the vicinity of the tunnel boring face, reducing the distance from the air outlet to the boring face and increasing the air velocity can improve the dust removal effect. This conclusion can provide theoretical basis and certain guidance for the evolution of dust and dust prevention in the tunnel construction process in plateau area.
- ArticleBublitz F, Sahota NK, Oetomo A, Fadrique L, Morita PP.BMJ Open. 2020 10 31;10(10):e033758.INTRODUCTION: For the first time in human history, the number of older people will be higher than the number of children. The prevalence of chronic diseases, such as hypertension, cardiovascular disease, diabetes and mental disorders in older adults is high. Given that, it is essential to make usage of related technology to provide improved health conditions and reduce the costs for promoting ageing in place, and that is precisely the aim of Ambient Assisted Living technology. Considering that these systems provide significant benefit to a vast number of stakeholders, can be applied to the functional diversity of application domains and have high economic and social impacts, it is essential to create reusable and interoperable platforms and standards that are able to deal with the heterogeneity of applications and domains. In this sense, reference architectures have been proposed and evaluated. A comprehensive scoping review concerning the reference architectures must clarify specific aspects, such as what the main domains are and how the solutions effectively deal with them.
METHODS: This scoping review will follow the methodology framework defined in 'Scoping studies: advancing the methodology'. In this methodological framework, six stages are proposed for scoping review studies: identifying the research question; identifying relevant studies; study selection; charting the data; collating, summarising and reporting the results; and consultation. The research questions aim to investigate what are the motivations, stakeholders, benefits, domains, approaches, architectural components and governance aspects of the proposed reference architectures and models. The team will focus on the Scopus Document Search, PubMed (MEDLINE), IEEE Xplore Digital Library, ACM Digital Library and Science Direct electronic research databases. The search query is a combination of terms related to Ambient Assisted Living AND Reference Architecture.
ETHICS AND DISSEMINATION: This is a scoping review study and there is no requirement for ethical approval, as primary data will not be collected. The results from this scoping review will be published in a peer-reviewed journal and reported at scientific meetings. We intend to share the results with the International Standards and Conformity Assessment - SyC AAL from Canada to use the review as a basis for establishing an assessment model of reference architectures. - ArticleMinkov D, Angelov G, Nikolov D, Rusev R, Marquez E, Fernandez S.Opt Express. 2024 Sep 09;32(19):33758-33778.UV/Vis/NIR transmittance spectra T(λ) are often used for the characterization of thin films in both spectrophotometry and spectroscopic ellipsometry. T(λ) are inherently noisy due to noise generated by the measuring equipment and the environment. Nevertheless, film characterizations are usually performed either without denoising T(λ) or by smoothing it, which should limit the characterization accuracy. In this study is proposed a method, abbreviated as SMEDM, for denoising of UV/Vis/NIR T(λ). The input to SMEDM consists of several intrinsic mode functions (IMFs) obtained from the decomposition of T(λ) by the complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN). In essence, SMEDM uses smoothed median envelopes of IMFs containing apparent noise features and computes the noise of T(λ). Eight model spectra T(λ) of a thin film on a thick substrate and two measured spectra T(λ) of such samples are denoised by SMEDM and other methods most suitable for denoising of such spectra. It is demonstrated that, in all studied cases, the most accurate denoising of the model spectra is obtained by SMEDM utilizing CEEMDAN. Magnitude accuracy of the computed noise MACN > 70% is achieved even for model noises with a magnitude smaller than that of the two experimental spectra.
- ArticleWei C, Chi H, Jiang S, Zheng L, Zhang H, Liu Y.Opt Express. 2020 Oct 26;28(22):33758-33766.In this paper, we fabricate the bulk-like multilayer platinum diselenide (PtSe2) and employ it as saturable absorber (SA) for a passively Q-switched fiber laser operating at 2865 nm for the first time, to the best of our knowledge. The nonlinear optical measurements of the bulk-like multilayer PtSe2 reveal efficient saturable absorption property at around 3 µm showing a modulation depth of 8.54% and a saturation intensity of 0.074 GW/cm2. By introducing the bulk-like PtSe2-SA into the Ho3+/Pr3+ co-doped ZBLAN fiber laser, stable Q-switched pulses with a duration as short as 620 ns are achieved at the pulse repetition rate of 238.1 kHz. The maximum average power is 93 mW, corresponding to a peak power of 0.63 W. The excellent long-term stability of the PtSe2-SA was also verified utilizing the same experimental setup after 40 days of ambient storage of the PtSe2 sample. The results not only validate the excellent nonlinear optical performance of PtSe2, but also indicate that the bulk-like PtSe2 is a promising long-term stable SA material under ambient conditions for nanosecond pulse generation in the 3-µm mid-infrared spectral region.
- ArticleRen J, Datta R, Shioya H, Li Y, Oki E, Biedermann V, Bharti A, Kufe D.J Biol Chem. 2002 Sep 13;277(37):33758-65.Protein kinase C (PKC) delta is cleaved by caspase-3 to a kinase-active catalytic fragment (PKCdeltaCF) in the apoptotic response of cells to DNA damage. Expression of PKCdeltaCF contributes to the induction of apoptosis by mechanisms that are presently unknown. Here we demonstrate that PKCdeltaCF associates with p73beta, a structural and functional homologue of the p53 tumor suppressor. The results show that PKCdeltaCF phosphorylates the p73beta transactivation and DNA-binding domains. One PKCdeltaCF-phosphorylation site has been mapped to Ser-289 in the p73beta DNA-binding domain. PKCdeltaCF-mediated phosphorylation of p73beta is associated with accumulation of p73beta and induction of p73beta-mediated transactivation. By contrast, PKCdeltaCF-induced activation of p73beta is attenuated by mutating Ser-289 to Ala (S289A). The results also demonstrate that PKCdeltaCF stimulates p73beta-mediated apoptosis and that this response is attenuated with the p73beta(S289A) mutant. These findings demonstrate that cleavage of PKCdelta to PKCdeltaCF induces apoptosis by a mechanism in part dependent on PKCdeltaCF-mediated phosphorylation of the p73beta Ser-289 site.
- ArticleKindermans PJ, Verstraeten D, Schrauwen B.PLoS One. 2012;7(4):e33758.This work introduces a novel classifier for a P300-based speller, which, contrary to common methods, can be trained entirely unsupervisedly using an Expectation Maximization approach, eliminating the need for costly dataset collection or tedious calibration sessions. We use publicly available datasets for validation of our method and show that our unsupervised classifier performs competitively with supervised state-of-the-art spellers. Finally, we demonstrate the added value of our method in different experimental settings which reflect realistic usage situations of increasing difficulty and which would be difficult or impossible to tackle with existing supervised or adaptive methods.
- ArticleWang B, Wang Z, Dou B, Ma Y, Liang Y.RSC Adv. 2021 Oct 08;11(53):33744-33758.A thermochemical energy storage (TCES) system can adjust problems of unstable energy supply for solar concentrating power plants. Mn2O3/Mn3O4 system is a promising TCES system, but it has the problem of a difficult reoxidation process. In this paper, TiO2 was doped into the manganese oxide TCES system to solve this problem and the factors which influence the performance of this method were analyzed. The different performances between commercial Mn2O3 (Mn) and Mn2O3 synthesized by the Pechini method (PCMn), and different scales of doping agents (25Ti, 100Ti) were compared. Because of the formation of the Mn2TiO4, adding TiO2 into the manganese oxide TCES system could improve its reoxidation process obviously. During single complete redox process, PCMn had better performance than Mn whether doped with TiO2 or not, but Mn had a higher optimum oxidation temperature and a narrow temperature range of the redox reactions after adding TiO2. Adding 25Ti could bring higher energy storage density than adding 100Ti, and the optimal doping ratio was 0.05. As the doping ratio of 25Ti was increased, the activation energy (E a) was increased and then decreased. The E a of the samples doped with 25Ti was higher than that doped with 100Ti. Moreover, the E a of the 25Mn0.05 was decreased firstly and then was increased in the later stage of the reaction. The doped Mn samples exhibited better performance and lower attenuation than the doped PCMn samples after 30 cycles. During cyclic tests, the Mn2TiO4 was initially formed at the boundary between Mn2O3 and TiO2, and it was generated continuously with the extension of operating time. Therefore, the operating temperature, morphology of the Mn2O3, the doping agents, the doping ratio, and the phase change with the operating time should be all considered when doping TiO2 into the Mn2O3/Mn3O4 TCES system to improve its performance. Moreover, the results obtained from Mn-Ti systems would make a lot sense when other similar systems are considered, such as Mn-Fe, Mn-Si, Mn-Cr, etc.
- ArticleZheng L, Price WE, Nghiem LD.Environ Sci Pollut Res Int. 2019 Nov;26(33):33758-33769.In this study, forward osmosis (FO) membranes and fouling solutions were systematically characterized to elucidate the effects of organic fouling on the rejection of two pharmaceutically active compounds, namely, sulfamethoxazole and carbamazepine. Municipal wastewater resulted in a more severe flux decline compared to humic acid and sodium alginate fouling solutions. This result is consistent with the molecular weight distribution of these foulant solutions. Liquid chromatography with organic carbon detection analysis shows that municipal wastewater consists of mostly low molecular weight acids and neutrals, which produce a more compact cake layer on the membrane surface. By contrast, humic acid and sodium alginate consist of large molecular weight humic substances and biopolymers, respectively. The results also show that membrane fouling can significantly alter the membrane surface charge and hydrophobicity as well as the reverse salt flux. In particular, the reverse salt flux of a fouled membrane was significantly higher than that under clean conditions. Although the rejection of sulfamethoxazole and carbamazepine by FO membrane was high, a discernible impact of fouling on their rejection could still be observed. The results show that size exclusion is a major rejection mechanism of both sulfamethoxazole and carbamazepine. However, they respond to membrane fouling differently. Membrane fouling results in an increase in sulfamethoxazole rejection while carbamazepine rejection decreases due to membrane fouling.
- ArticleZhang W, Zhang F, Xu B, Li Y, Wang L, Zhang B, Guo Y, Gardner JM, Sun L, Kloo L.ACS Appl Mater Interfaces. 2020 Jul 29;12(30):33751-33758.Despite the ubiquity and importance of organic hole-transport materials in photovoltaic devices, their intrinsic low conductivity remains a drawback. Thus, chemical doping is an indispensable solution to this drawback and is essentially always required. The most widely used p-type dopant, FK209, is a cobalt coordination complex. By reducing Co(III) to Co(II), Spiro-OMeTAD becomes partially oxidized, and the film conductivity is initially increased. In order to further increase the conductivity, the hygroscopic co-dopant LiTFSI is typically needed. However, lithium salts are normally quite hygroscopic, and thus, water absorption has been suggested as a significant reason for perovskite degradation and therefore limited device stability. In this work, we report a LiTFSI-free doping process by applying organic salts in relatively high amounts. The film conductivity and morphology have been studied at different doping amounts. The resulting solar cell devices show comparable power conversion efficiencies to those based on conventional LiTFSI-doped Spiro-OMeTAD but show considerably better long-term device stability in an ambient atmosphere.
- ArticleLi GF, Divinagracia M, Labata MF, Ocon JD, Abel Chuang PY.ACS Appl Mater Interfaces. 2019 Sep 18;11(37):33748-33758.Traditional understanding of electrocatalytic reactions generally focuses on either covalent interactions between adsorbates and the reaction interface (i.e., electrical double layer, EDL) or electrostatic interactions between electrolyte ions. Here, our work provides valuable insights into interfacial structure and ionic interactions during alkaline oxygen evolution reaction (OER). The importance of inner-sphere OH- adsorption is demonstrated as the IrOx activity in 4.0 M KOH is 6.5 times higher than that in 0.1 M KOH. Adding NaNO3 as a supporting electrolyte, which is found to be inert for long-term stability, complicates the electrocatalytic reaction in a half cell. The nonspecially adsorbed Na+ in the outer compact interfacial layer is suggested to form a stronger noncovalent interaction with OH- through hydrogen bond than adsorbed K+, leading to the decrease of interfacial OH- mobility. This hypothesis highlights the importance of outer-sphere adsorption for the OER, which is generally recognized as a pure inner-sphere process. Meanwhile, based on our experimental observations, the pseudocapacitive behavior of solid-state redox might be more reliable in quantifying active sites for OER than that measured from the conventional EDL charging capacitive process. The interfacial oxygen transport is observed to improve with increasing electrolyte conductivity, ascribing to the increased accessible active sites. The durability results in a liquid alkaline electrolyzer which shows that adding NaNO3 into KOH solution leads to additional degradation of OER activity and long-term stability. These findings provide an improved understanding of the mechanistic details and structural motifs required for efficient and robust electrocatalysis.
- ArticleZhao J, Xu X, Zhou W, Blakey I, Liu S, Zhu Z.ACS Appl Mater Interfaces. 2017 Oct 04;9(39):33758-33765.Performance degradation caused by carbon deposition substantially restricts the development of direct methane solid oxide fuel cells (SOFCs). Here, an internal reforming layer composed of Ni supported on proton conducting La-doped ceria, such as La2Ce2O7 (LDC) and La1.95Sm0.05Ce2O7 (LSDC) is applied over conventional Ni-Ce0.8Sm0.2O2-x (SDC) anodes for direct methane SOFCs. The proton conducting layer can adsorb water for internal reforming thus significantly improving the performance of the direct methane SOFCs. In situ Raman and FTIR results confirm the water adsorption capacity of LDC and LSDC. They also exhibit excellent phase stability in wet CO2 at 650 °C for 10 h, which ensures that the additional catalyst layer maintains structure stability during the internal reforming. In wet methane at 650 °C, the peak power density of the conventional cell is only 580 ± 20 mW cm-2, and increases to 699 ± 20 and 639 ± 20 mW cm-2 with the addition of Ni-LDC and -LSDC layers, respectively. For the stability test in wet methane at 650 °C and 0.2 A cm-2, the voltage of the conventional cell starts to drop dramatically in 10 h, while the Ni-LDC and -LSDC catalyst layers operate stably in 26 h under the identical conditions. These catalyst layers even show comparable stability in dry and wet methane in 26 h, but for longer operation, the wet methane is still preferred for maintaining the stability of the cell.
- BookSounds Wild and Broken : Sonic Marvels, Evolution's Creativity, and the Crisis of Sensory ExtinctionDavid George Haskell.Summary: "A rich exploration of how the evolution of both natural and manmade sounds have shaped us and the world, and how the world's acoustic diversity is currently in grave danger of being destroyed. We live on a planet that is wrapped in the diverse acoustic marvels of song and speech. Yet never has this diversity been so threatened as it is now. Braiding his experience as a listener and an ecologist with the latest scientific discoveries, David Haskell explores the acoustic wonders of our planet. Starting in deep time with the origins of animal song and traversing the whole arc of Earth's history, he illuminates and celebrates the creative processes that have produced the varied sounds of our world. From the powers of animal sexuality and environmental change, to the unpredictable, improvisational whims of genetic evolution and cultural change, sounds on Earth are the products of and catalysts for vibrant ecosystems. Four interconnected sensory crises are currently diminishing the vitality of our sonic world. Deforestation is erasing the most complex communities of sounds the world has ever known. In the oceans, machine noise has created a living hell for the most acoustically sensitive animals on the planet. In cities, noise has resulted in dire sonic inequities among people, the result of racism, sexism, and power asymmetries. Last, in forgetting or being barred from hearing the voices of the living Earth, we lose both the experience of joyful connection and the foundation for ethics and action. As wild sounds disappear forever and human noise smothers other voices, the Earth becomes flatter, blander. According to Haskell, this decline is not a mere loss of sensory ornament. Sound is a generative force, and so the erasure of sonic diversity makes the world less creative. His book is an invitation to listen, wonder, belong, and act."-- Provided by publisher.
Contents:
Origins. Primal sound and the ancient roots of hearing
Unity and diversity
Sensory bargains and biases
The flourishing of animal sounds. Predators, silence, wings
Flowers oceans, milk
Evolution's creative powers. Air, water, wood
In the clamor
Sexuality and beauty
Vocal learning and culture
The imprints of deep time
Human music and belonging. Bone, ivory, breath
Resonant spaces
Music, forest, body
Diminishment, crisis, and injustice. Forests
Oceans
Cities
Listening. In community
In the deep past and future.Digital Access 2022Limited to 1 simultaneous user - ArticleSchieb H, Kratzin H, Jahn O, Möbius W, Rabe S, Staufenbiel M, Wiltfang J, Klafki HW.J Biol Chem. 2011 Sep 30;286(39):33747-58.In this study, we report a detailed analysis of the different variants of amyloid-β (Aβ) peptides in the brains and the cerebrospinal fluid from APP23 transgenic mice, expressing amyloid precursor protein with the Swedish familial Alzheimer disease mutation, at different ages. Using one- and two-dimensional gel electrophoresis, immunoblotting, and mass spectrometry, we identified the Aβ peptides Aβ(1-40), -(1-42), -(1-39), -(1-38), -(1-37), -(2-40), and -(3-40) as well as minor amounts of pyroglutamate-modified Aβ (Aβ(N3pE)) and endogenous murine Aβ in brains from 24-month-old mice. Chemical modifications of the N-terminal amino group of Aβ were identified that had clearly been introduced during standard experimental procedures. To address this issue, we additionally applied amyloid extraction in ultrapure water. Clear differences between APP23 mice and Alzheimer disease (AD) brain samples were observed in terms of the relative abundance of specific variants of Aβ peptides, such as Aβ(N3pE), Aβ(1-42), and N-terminally truncated Aβ(2/3-42). These differences to human AD amyloid were also noticed in a related mouse line transgenic for human wild type amyloid precursor protein. Taken together, our findings suggest different underlying molecular mechanisms driving the amyloid deposition in transgenic mice and AD patients.
- ArticleSinclair JF, O'Brien AD.J Biol Chem. 2004 Aug 06;279(32):33751-8.The outer membrane adhesins of enteropathogenic Escherichia coli, Citrobacter rodentium, and enterohemorrhagic E. coli (EHEC) O157:H7 that mediate attach and efface intestinal lesions are classified as intimin alpha, beta, and gamma, respectively. Each of these intimin types binds to its cognate, bacterially encoded receptor (called Tir for translocated intimin receptor) to promote tight adherence of the organism to the host-cell plasma membrane. We previously reported that gamma intimin of EHEC O157:H7 also bound to a eucaryotic receptor that we determined was nucleolin. The objective of this study was to investigate in vitro and in vivo the interactions of intimins alpha, beta, and gamma with nucleolin in the presence of Tir from EHEC O157:H7. Protein binding experiments demonstrated that intimin of types alpha, beta, and gamma bound nucleolin with similar affinity. Moreover, all three intimin types co-localized with regions of nucleolin expressed on the surface of HEp-2 cells. When intimin alpha, beta, or gamma bound to Tir in vitro, the intimin interaction with nucleolin was blocked. Both Tir and nucleolin accumulated beneath intimin-presenting bacteria that had attached to the surface of HEp-2 cells. Taken together, these findings suggest that nucleolin is involved in bacterial adherence promoted by all intimin types and that Tir and nucleolin compete for intimin during adherence.
- ArticlePagano A, Ruegg D, Litschig S, Stoehr N, Stierlin C, Heinrich M, Floersheim P, Prezèau L, Carroll F, Pin JP, Cambria A, Vranesic I, Flor PJ, Gasparini F, Kuhn R.J Biol Chem. 2000 Oct 27;275(43):33750-8.We have investigated the mechanism of inhibition and site of action of the novel human metabotropic glutamate receptor 5 (hmGluR5) antagonist 2-methyl-6-(phenylethynyl)pyridine (MPEP), which is structurally unrelated to classical metabotropic glutamate receptor (mGluR) ligands. Schild analysis indicated that MPEP acts in a non-competitive manner. MPEP also inhibited to a large extent constitutive receptor activity in cells transiently overexpressing rat mGluR5, suggesting that MPEP acts as an inverse agonist. To investigate the molecular determinants that govern selective ligand binding, a mutagenesis study was performed using chimeras and single amino acid substitutions of hmGluR1 and hmGluR5. The mutants were tested for binding of the novel mGluR5 radioligand [(3)H]2-methyl-6-(3-methoxyphenyl)ethynyl pyridine (M-MPEP), a close analog of MPEP. Replacement of Ala-810 in transmembrane (TM) VII or Pro-655 and Ser-658 in TMIII with the homologous residues of hmGluR1 abolished radioligand binding. In contrast, the reciprocal hmGluR1 mutant bearing these three residues of hmGluR5 showed high affinity for [(3)H]M-MPEP. Radioligand binding to these mutants was also inhibited by 7-hydroxyiminocyclopropan[b]chromen-1a-carboxylic acid ethyl ester (CPCCOEt), a structurally unrelated non-competitive mGluR1 antagonist previously shown to interact with residues Thr-815 and Ala-818 in TMVII of hmGluR1. These results indicate that MPEP and CPCCOEt bind to overlapping binding pockets in the TM region of group I mGluRs but interact with different non-conserved residues.
- ArticleKim Y, Ratziu V, Choi SG, Lalazar A, Theiss G, Dang Q, Kim SJ, Friedman SL.J Biol Chem. 1998 Dec 11;273(50):33750-8.We have explored the regulation of transforming growth factor beta (TGF-beta) activity in tissue repair by examining the interactions of Zf9/core promoter-binding protein, a Kruppel-like zinc finger transcription factor induced early in hepatic stellate cell (HSC) activation, with promoters for TGF-beta1 and TGF-beta receptors, types I and II. Nuclear extracts from culture-activated HSCs bound avidly by electrophoretic mobility shift assay to two tandem GC boxes within the TGF-beta1 promoter but minimally to a single GC box; these results correlated with transactivation by Zf9 of TGF-beta1 promoter-reporters. Zf9 transactivated the full-length TGF-beta1 promoter in either primary HSCs, HSC-T6 cells (an SV40-immortalized rat HSC line), Hep G2 cells, or Drosophila Schneider (S2) cells. Recombinant Zf9-GST also bound to GC box sequences within the promoters for the types I and II TGF-beta receptors. Both type I and type II TGF-beta receptor promoters were also transactivated by Zf9 in mammalian cells but not in S2 cells. In contrast, Sp1 significantly transactivated both receptor promoters in S2 cells. These results suggest that (a) Zf9/core promoter-binding protein may enhance TGF-beta activity through transactivation of both the TGF-beta1 gene and its key signaling receptors, and (b) transactivating potential of Zf9 and Sp1 toward promoters for TGF-beta1 and its receptors are not identical and depend on the cellular context.