Combinatorial Applications Research Articles

Enhanced antibacterial potential of berberine via synergism with chitosan nanoparticles

From the last three decades nanoparticles have captivated tremendous attention in the field of biomedical research owing to their diverse pharmaceutical and therapeutic applications. Chitosan has gained significant attention in pharmaceutics and food industries due to its remarkable antimicrobial activities and biocompatibility. Furthermore, chitosan nanoparticles have been explored widely for increased antimicrobial activities against broad range of multi drug resistant bacterial strains. Antimicrobials derived from natural herbs have also been explored. Berberine, a plant alkaloid has also proven efficacy against a broad spectrum of microorganisms. Combinatorial employment of both berberine and chitosan nanoparticles could be employed to enhance their antibacterial action. Chitosan nanoparticles were developed by ionic gelation methods and physicochemically characterized. Chitosan nanoparticles and berberine alone have showed notable antibacterial activity against both Bacillus subtilis and Staphylococcus aureus. However, synergy has been observed to improve their inhibitory action. The time kill kinetics revealed that the synergy has augmented the antibacterial potential of chitosan nanoparticles and berberine. The synergy between berberine and chitosan nanoparticles demonstrates combinatorial application of compounds as an efficient, novel therapeutic agents against antibiotic resistant bacterial infections.

Towards a biotechnological platform for the production of human pro-angiogenic growth factors in the green alga Chlamydomonas reinhardtii.

The recent use of photosynthetic organisms such as Chlamydomonas reinhardtii in biomedical applications has demonstrated their potential for the treatment of acute and chronic tissue hypoxia. Moreover, transgenic microalgae have been suggested as an alternative in situ drug delivery system. In this study, we set out to identify the best available combination of strains and expression vectors to establish a robust platform for the expression of human pro-angiogenic growth factors, i.e., hVEGF-165, hPDGF-B, and hSDF-1, in biomedical settings. As a case study, combinations of two expression vectors (pOpt and pBC1) and two C. reinhardtii strains (UVM4 and UVM11) were compared with respect to hVEGF-165 transgene expression by determination of steady-state levels of transgenic transcripts and immunological detection of recombinant proteins produced and secreted by the generated strains. The results revealed the combination of the UVM11 strain with the pBC1 vector to be the most efficient one for high-level hVEGF-165 production. To assess the robustness of this finding, the selected combination was used to create hPDGF-B and hSDF-1 transgenic strains for optimized recombinant protein expression. Furthermore, biological activity and functionality of algal-produced recombinant pro-angiogenic growth factors were assessed by receptor phosphorylation and in vitro angiogenesis assays. The results obtained revealed a potentiating effect in the combinatorial application of transgenic strains expressing either of the three growth factors on endothelial cell tube formation ability, and thus support the idea of using transgenic algae expressing pro-angiogenic growth factors in wound healing approaches.

From Ramanujan graphs to Ramanujan complexes

Ramanujan graphs are graphs whose spectrum is bounded optimally. Such graphs have found numerous applications in combinatorics and computer science. In recent years, a high-dimensional theory has emerged. In this paper, these developments are surveyed. After explaining their connection to the Ramanujan conjecture, we will present some old and new results with an emphasis on random walks on these discrete objects and on the Euclidean spheres. The latter lead to ‘golden gates’ which are of importance in quantum computation. This article is part of a discussion meeting issue ‘Srinivasa Ramanujan: in celebration of the centenary of his election as FRS’.

Survival-Based Gene Expression Analysis of Chinese HCC Specimens Revealed Prognostic Biological Determinants Regulating Cancer Growth and Tumor Immunity

To identify important druggable targets and immunological determinants associated with the overall survival (OS) of hepatocellular carcinoma (HCC) patients, we interrogated 279 Chinese HCC samples, mostly in early stage, with the NanoString platform assessing the expression of 1,173 genes involved in cell-growth signaling pathways, cellular machineries and tumor immunity. A prognostic model was constructed using 17 genes with bootstrap-corrected C-index of 0.81 for the OS. Among the genes associated with worse OS, cell-growth related druggable targets CHK1 and EZH2 were selected for in vitro and in vivo tumor growth studies. HCC cell line clonogenic assays and mice xenograft models demonstrated that the combinatorial application of CHK1 inhibitor and EZH2 inhibitor resulted in significant suppression of HCC tumor growth. On the tumor immunity front, we discovered that genes enriched in regulating CD8+ T cells and activating NK cells contributed to prolonged OS. Our findings provide potential rationale for investigating combinatorial targeted therapies and immunotherapies in specific subsets of early-stage HCC with distinct gene expression characteristics. Funding: This work was supported by National Natural Science Fund of China (Grant numbers: No.81672330; No. 81871916; No. 81472218), Talent Development Program of Zhongshan Hospital (2015ZSYXGG), and by Genentech Inc., a member of the Roche Group. Declaration of Interest: Chun Sun, Bonnie Liu, Kwame Okrah, Xu Cao, Jian-Jun Guo, Shi-Jing Fu, Su-Chun Li, Hang-jun Dai, Mark R. Lackner, Astrid Kiermaier, Shih-Min A. Huang and Gang Cheng are employees of F. Hoffmann-La Roche/Genentech Inc. All other authors declare no conflict of interest. Ethical Approval: This study was approved, and the collection of written informed consent forms was waived, by the institutional review board of SZH under the condition that all samples were anonymized in this study.

Combinatorial n-fold integer programming and applications

Many fundamental $$\mathsf {NP}$$ -hard problems can be formulated as integer linear programs (ILPs). A famous algorithm by Lenstra solves ILPs in time that is exponential only in the dimension of the program, and polynomial in the size of the ILP. That algorithm became a ubiquitous tool in the design of fixed-parameter algorithms for $$\mathsf {NP}$$ -hard problems, where one wishes to isolate the hardness of a problem by some parameter. However, in many cases using Lenstra’s algorithm has two drawbacks: First, the run time of the resulting algorithms is often double-exponential in the parameter, and second, an ILP formulation in small dimension cannot easily express problems involving many different costs. Inspired by the work of Hemmecke et al. (Math Program 137(1–2, Ser. A):325–341, 2013), we develop a single-exponential algorithm for so-called combinatorial n-fold integer programs, which are remarkably similar to prior ILP formulations for various problems, but unlike them, also allow variable dimension. We then apply our algorithm to many relevant problems problems like Closest String, Swap Bribery, Weighted Set Multicover, and several others, and obtain exponential speedups in the dependence on the respective parameters, the input size, or both. Unlike Lenstra’s algorithm, which is essentially a bounded search tree algorithm, our result uses the technique of augmenting steps. At its heart is a deep result stating that in combinatorial n-fold IPs, existence of an augmenting step implies existence of a “local” augmenting step, which can be found using dynamic programming. Our results provide an important insight into many problems by showing that they exhibit this phenomenon, and highlights the importance of augmentation techniques.

Combinatorial Anatomic and Functional Neural Tract Mapping for Stereotactic Radiosurgery Planning.

IntroductionStereotactic radiosurgery (SRS) is effective and safe for the treatment of the vast majority of brain metastases (BMs). SRS is increasingly used for the simultaneous treatment of multiple lesions, retreatment of recurrence, or subsequent treatment of new lesions. Although radiation injury is relatively uncommon, with the increased utilization of SRS, it is imperative to develop approaches to assess and mitigate radiation-induced neurologic toxicity. Multiple factors influence the development of radiation injury, including patient age, genomic variations, prior treatment, dose and volume treated, and anatomic location. Functional neural structure proximity to SRS targets is a critical factor in developing a systematic integrated risk assessment for SRS patients.MethodsWe developed an approach for risk assessment based on the combinatorial application of i) the anatomic localization of target lesions using a reference neuroanatomical/functional imaging atlas merged with patient-specific imaging and ii) validation with functional MRI (fMRI) and diffusion tensor imaging MRI (DTI-MRI) to identify neural tracts.ResultsIn the case of a thalamic/midbrain junction breast carcinoma metastasis, the reference image analysis revealed proximity to the corticospinal tract (CST), which was validated by functional DTI-MRI. Dose-volume exposure of the CST could be estimated and considered in the development of a final treatment plan.ConclusionMerging pretreatment MR imaging with neuroanatomical/functional reference MRIs and subsequent validation with fMRI or DTI-MRI may prove to be a valuable approach to screen for neural risks in individual SRS patients. Incorporating this approach in larger studies could further our understanding of dose tolerances in a broad range of neural structures.

Fungal endophytes alleviate drought-induced oxidative stress in mandarin (Citrus reticulata L.): Toward regulating the ascorbate–glutathione cycle

Fungal endophytes grow symbiotically inside a diverse array of plants, and improve viability of the hosts in various mutualistic manners. We investigated the effects of inoculating mandarin endophytic fungi, introduced formerly by our group, i.e. Penicillium citrinum, Aurobassium pullunts and Dothideomycetes sp., individually and in combination with each other on the reactive oxygen species (ROS) scavenging and antioxidant functions in plants under drought stress. To do so, mandarin (Citrus reticulata) scions grafted on Bakraii [Citrus reticulata × Citrus limetta] (Mandarin/Bakraii) were subjected to four irrigations interval including 2, 4, 6 and 8 days, in present/absent of the fungal endophytes. The results indicated that drought stress significantly reduced growth, chlorophyll, carotenoid content and chlorophyll fluorescence (Fv/Fm) of the plants lacking endophytes. Combinatory applications with three fungal endophytes (P. citrinum + A. pullunts + Dothideomycetes sp.) significantly improved the above-mentioned parameters under drought stress. H2O2, O2− and lipid peroxidation level were significantly reduced in the plants inoculated with fungal endophytes. Drought stress significantly increased activities of ascorbate peroxidase (APX), superoxide dismutase (SOD) and glutathione reductase (GR) and levels of ascorbate (ASA) and glutathione (GSH) and decreased activities of catalase (CAT), monodehydroascorbate reductase (MDHAR) and dehydroascorbate reductase (DHAR). Fungal endophytes inoculated drought stressed seedlings enhanced the above-mentioned indicators as compared to the drought-stressed plants without fungal endophytes, as well as in the ratios of reduced ascorbate/dehydroascorbic acid (AsA/DHA) and reduced glutathione/oxidized glutathione (GSH/GSSG). Overall, fungal endophyte inoculation improved drought tolerance and reduced the accumulation of ROS by increasing their scavenging via improving the redox state of ascorbate and glutathione and promotion of antioxidant enzymes activity.

Synergistic Activity of Fosfomycin, Ciprofloxacin, and Gentamicin Against Escherichia coli and Pseudomonas aeruginosa Biofilms.

Gram-negative (GN) rods cause about 10% periprosthetic joint infection (PJI) and represent an increasing challenge due to emergence of antimicrobial resistance. Escherichia coli and Pseudomonas aeruginosa are among the most common cause of GN-PJI and ciprofloxacin is the first-line antibiotic. Due to emergence of fluoroquinolone resistance, we evaluated in vitro the activity of fosfomycin, ciprofloxacin, and gentamicin, alone and in combinations, against E. coli and P. aeruginosa biofilms. Conventional microbiological tests and isothermal microcalorimetry were applied to investigate the anti-biofilm activity of the selected antibiotics against standard laboratory strains as well as clinical strains isolated from patients with prosthetic joint associated infections. The biofilm susceptibility to each antibiotic varied widely among strains, while fosfomycin presented a poor anti-biofilm activity against P. aeruginosa. Synergism of two-pair antibiotic combinations was observed against different clinical strains from both species. Highest synergism was found for the fosfomycin/gentamicin combination against the biofilm of E. coli strains (75%), including a gentamicin-resistant but fosfomycin-susceptible strain, whereas the gentamicin/ciprofloxacin combination presented synergism with higher frequency against the biofilm of P. aeruginosa strains (71.4%). A hypothetical bacteriolysis effect of gentamicin could explain why combinations with this antibiotic seem to be particularly effective. Still, the underlying mechanism of the synergistic effect on biofilms is unknown. In conclusion, combinatorial antibiotic application has shown to be more effective against biofilms compared to monotherapy. Further in vivo and clinical studies are essential to define the potential treatment regimen based on our results.

Free chlorine and phytic acid synergistically inactivated conidia of Aspergillus spp.

Chlorination has been widely used to disinfect various microbials in the environment, but its fungicidal activity is known to be limited. Here, we demonstrate that a combinatorial treatment with free chlorine and phytic acid exerted high fungicidal activities against selected species of Aspergillus. Treatment with either chlorine (7 mg/l) or phytic acid (∼400 mg/l) without pH adjustment caused marginal inactivation of Aspergillus niger conidia within 5 min. However, the combinatorial treatment with free chlorine and phytic acid inactivated 98% of A. niger conidia within 5min ($$\overline {\rm{C}} {\rm{T}} = 25.7\;{\rm{mg/}}l \cdot \min $$). Overall fungicidal efficiency of combinatorial application was higher (∼256%) than the sum of inactivation levels by individual treatment, suggesting a synergistic effect between free chlorine and phytic acid. Transmission electron microscopy observation showed that free chlorine primarily disrupted nucleo-cytosolic organs, whereas phytic acid preferentially disintegrated the cell wall and plasma membrane. The combination of both agents demolished the conidial structure of A. niger. The effects of these chemicals on the cell membrane were verified with propidium iodide staining, lipid peroxidation, and extracellular ATP secretion. Fungicidal activities of chlorine and phytic acid were further confirmed against A. parasiticus and A. flavus. Our data suggest that the mixture of free chlorine and phytic acid without any additional preparation may efficiently disinfect Aspergillus spp. through the synergistic activities of individual components.

Characterization of polyclonal antibodies to Herpes Simplex Virus types 1 and 2

ABSTRACTInfections with herpes simplex virus (HSV) types 1 and 2 have been linked to oral, facial, genital lesions, as well as some visceral organ changes in patients under immunosuppressed conditions. Immunohistochemistry (IHC) with HSV antibodies is used for identification of the viruses in tissue samples. In this study, two polyclonal antibodies, prepared separately with HSV-1 and HSV-2 immunogens, were characterized in comparison to a monoclonal antibody to HSV-1 (10A3). The polyclonal anti-HSV-1 and monoclonal antibody 10A3 were shown to be reactive to viral proteins of both HSV-1 and HSV-2 on Western blots, while the polyclonal anti-HSV-2 was reactive to HSV-2 proteins, but not to those of HSV-1. Cross-reactivity was not observed to proteins of six other frequently encountered herpes viruses. IHC characterization was performed on 29 cases of HSV-infected tissue samples, 61 samples infected with other herpes viruses and 35 samples without known infection. By IHC, the polyclonal anti-HSV-1 and a monoclonal antibody 10A3 exhibited a signal, mainly in a nuclear pattern, in all of the HSV-infected samples and not in other tissue types. A positive signal, mainly in the cytoplasm, was identified with the polyclonal anti-HSV-2 in 21 of the 29 HSV-infected samples. Genotyping analysis was successful in 14 of the HSV-infected samples, with IHC HSV-2 positivity correlative to the HSV-2 genotype. The results demonstrate that these antibodies are useful tools for identification of HSV-1 and HSV-2, and their combinatorial application may help to distinguish between these two types of infection.

Vincular patterns in inversion sequences

Inversion sequences have intriguing applications in combinatorics, computer sciences and polyhedral geometry. Ascent sequences, as one of the most important subsets of inversion sequences, were introduced by Bousquet-Mélou, Claesson, Dukes and Kitaev to encode the (2+2)-free posets. Pattern avoidance in ascent sequences was first studied by Ducan and Steingrímsson in 2011, while the systematic study of patterns in inversion sequences was initiated only recently by Corteel–Martinez–Savage–Weselcouch and Mansour–Shattuck. In this paper, we investigate systematically the enumeration of inversion or ascent sequences avoiding vincular patterns of length 3, where two of the three letters are required to be adjacent. Our results connect restricted inversion sequences and ascent sequences to a number of well-known combinatorial sequences including Bell numbers, Fishburn numbers, Powered Catalan numbers, Semi-Baxter numbers and the number of 3-noncrossing partitions. A variety of combinatorial bijections, known or newly constructed, are applied to achieve these interesting connections.

The behavior of Tutte polynomials of graphs under five graph operations and its applications

The Tutte polynomial of a graph has many important applications in combinatorics, physics, and biology. Graph operations, such as triangulation and subdivision, have been widely used in building complex network models. In this paper, we show how the Tutte polynomial changes with five graph operations. Firstly, we study the connections between graph G and its operation graphs: the triangulation graph R(G), the diamond graph Z(G), the quadrilateral graph Q(G), the 2-triangulation graph R2(G), and the Wheatstone bridge graph W(G), in the respect of spanning subgraphs. Secondly, using these relations, we investigate the structure of the set of spanning subgraphs of each operation graph, and find that it is constituted by 2|E(G)| disjoint subsets. Then, we derive the contribution of each subset by an indirect method. Finally, we gain the Tutte polynomials of these five operation graphs. Moreover, we consider the Tutte polynomials of the pseudofractal scale-free network and a classic diamond hierarchical lattice as an application. Our technique can be applied to study other graph polynomials.

Enhancing Lentiviral and Alpharetroviral Transduction of Human Hematopoietic Stem Cells for Clinical Application

Ex vivo retroviral gene transfer into CD34+ hematopoietic stem and progenitor cells (HSPCs) has demonstrated remarkable clinical success in gene therapy for monogenic hematopoietic disorders. However, little attention has been paid to enhancement of culture and transduction conditions to achieve reliable effects across patient and disease contexts and to maximize potential vector usage and reduce treatment cost. We systematically tested three HSPC culture media manufactured to cGMP and eight previously described transduction enhancers (TEs) to develop a state-of-the-art clinically applicable protocol. Six TEs enhanced lentiviral (LV) and five TEs facilitated alpharetroviral (ARV) CD34+ HSPC transduction when used alone. Combinatorial TE application tested with LV vectors yielded more potent effects, with up to a 5.6-fold increase in total expression of a reporter gene and up to a 3.8-fold increase in VCN. Application of one of the most promising combinations, the poloxamer LentiBOOST and protamine sulfate, for GMP-compliant manufacturing of a clinical-grade advanced therapy medicinal product (ATMP) increased total VCN by over 6-fold, with no major changes in global gene expression profiles or inadvertent loss of CD34+CD90+ HSPC populations. Application of these defined culture and transduction conditions is likely to significantly improve ex vivo gene therapy manufacturing protocols for HSPCs and downstream clinical efficacy.

Main Provisions Of The Concept Of Technology Of Diamond Cutting And Drilling Of Building Structures

The main provisions of the concept of technology of diamond cutting and drilling of building structures are considered. The innovativeness of the technology, its main possibilities and advantages are presented. Carrying out works with the help of this technology in underwater conditions expands its use when constructing and reconstructing hydraulic structure. The use of diamond drilling equipment with motors equipped with an internal combustion engine is considered. Drilling holes with a variable diameter during the reconstruction of the runways of airfields makes it possible to combine the landing mats into a single structure. The ability to cut inside the concrete mass, parallel to the front surface, has no analogues among the methods of concrete treatment. The use of this technology for producing blind openings in the body of concrete without weakening the structure is also unique. Work with precision quality in cutting and diamond drilling of concrete and reinforced concrete was noted by architects and began to be implemented in the manufacture of inter-room and inter-floor openings. Non-destructive approach to the fragmentation of building structures allows them to be reused. The technology of diamond cutting and drilling is located at the junction of new construction, repair, reconstruction of buildings and structures, and dismantling of structures. Attention is paid to the complexity and combinatorial application of diamond technology. Economic efficiency and ecological safety of diamond technology are presented. The main directions of further research for the development of technology are indicated.

Application of the combinatorial approaches of medicinal and aromatic plants with nanotechnology and its impacts on healthcare.

Medicinal and aromatic plants are natural raw materials. Since ancient times these herbal materials are being commonly used as herbal drugs, food products, and cosmetics. The phytomolecules isolated from the medicinal and aromatic plants (MAPs) are in high demand specifically in drug industries. However, these phytomolecules have certain limitations of low absorption, high toxicity, and other side effects, bioavailability and efficacy. These limitations may be overcome by using nanotechnological tools. The plant extract or essential oil of MAPs are also useful in the synthesis of nanoparticles. In future this combinatorial application of MAPs and nanotechnology would be advantageous in thehealthcare area. Literature search was performed using databases like Pubmed, Scopus and Google Scholar with the keywords "nanoparticles," "phytomolecules," "medicinal and aromatic plants" and "green synthesis of nanoparticles" in the text. Phytomolecules of medicinal and aromatic plants like curcumin, camptothecin, thymol, and eugenol have certain limitations of bioavailability, efficacy, and solubility. It limits its biological activity and therefore application in the biomedical area. The increment in the biological activity and sustained delivery was observed after the encapsulation of these potent phytomolecules encapsulated in the nanocarriers. Besides,MAPs and/or their molecules/oils mediate the synthesis of metal nanocarriers with less toxicity. This review highlights the impact of the combination of the MAPs with the nanotechnology along with the challenges. It would be an effective technique for the efficient delivery of different phytomolecules and also in the synthesis of novel nano-materials, which escalates the opportunity of exploration of potential molecules of MAPs. Graphical abstract Graphical representation of the combinatorial approach of MAPs and nanotechnology.

Novel monoclonal antibody therapeutics for metastatic castration resistant prostate cancer.

e14222 Background: Therapeutic potential of innate immunity comprising Natural killer cell based targets are beginning to unravel the complexity of immune responses. NK cells recognize and induce cytotoxicity of wide range of target cells, such as, tumor cells without prior antigen sensitization. In this study, we have studied Lectin-like transcript 1 (LLT1), a member of the C-type lectin super family, is expressed on target cells and various immune cells. LLT1 isoform 1, is known to interact with CD161, a critical receptor on NK cells. CD161 is expressed on most of human NK cells, NK-T cells, γδ T cells and so on. Tumors exploit the CD161- LLT1 interaction to evade host defense mechanism (“DO NOT KILL” signal); indicating LLT1 as an attractive immunotherapeutic strategy. Methods: Prostate cancer cell lines and other tumor cell lines were used to evaluate novel anti LLT1 antibodies for therapeutic potential - IFNγ production assays and tumor cell death assays were carried out. In vivo efficacy of these antibodies were established using PC3 xenograft in humanized mouse model (HuNOG-EXL). Results: Human androgen independent prostate cancer cell line, PC3 was studied for LLT1 expression and interactions with immune cells, to understand role of LLT1 in metastatic castration resistant prostate cancer (mCRPC). Overexpression of LLT1 on tumor cells was influenced by cytokines and various TLRs. Inhibition of CD161-LLT1 interaction with novel anti LLT1 antibodies leads to IFNγ production and consequent NK cell mediated cytotoxicity – hall mark of anti-tumor responses. Disruption of LLT1 - CD161 innate immunity axis with anti LLT1 antibody releases the break on NK cell cytotoxicity and hence, established a new therapeutic option. PC3 xenograft on HuNOG mouse revealed in vivo efficacy of LLT1 antibody. Significant tumor growth reduction was observed with specific anti LLT1 antibodies alone and in combination with check point antibodies. Thus, synergistic tumor growth reduction was established by combinatorial application of anti LLT1 antibody and PD1/PDL1 axis inhibitors. Conclusions: PC3 xenograft study and other results point to therapeutic opportunities in metastatic castration resistant prostate cancer, a disease condition which needs improved patient outcomes. The ligation of CD161/LLT1 will serve as a new immuno-oncology pair regulating innate and adaptive immune responses; novel human antibodies against LLT1 described here will bring therapeutic benefit to patients in need.

Several new classes of self-dual bent functions derived from involutions

Bent functions are a kind of Boolean functions which have the maximum Hamming distance to linear and affine functions, they have some interesting applications in combinatorics, coding theory, cryptography and sequences. However, generally speaking, how to find new bent functions is a hard work and is a hot research project during the past decades. A subclass of bent functions that has received attention since Dillon’s seminal thesis (1974) is the subclass of those Boolean functions that are equal to their dual (or Fourier transform in Dillon’s terminology): the so-called self dual bent functions. In this paper, we propose a construction of involutions from linear translators, and provide two methods for constructing new involutions by utilizing some given involutions. With the involutions presented in this paper, several new classes of self-dual bent functions are produced.

Normal and keloid fibroblasts are differentially influenced by IFN-γ and triamcinolone as well as by their combination.

Impaired wound healing as well as imbalanced cell proliferation and extracellular matrix synthesis and degeneration can cause aberrant scarring. The most severe impacts of such scarring on patients' lives are stigmatization and physical restriction. Although, a broad variety of combinatorial approaches with, e.g., glucocorticoids, chemotherapeutics, and immunomodulators are used, there is still a high recurrence rate of keloids. The aim of this study was to investigate which influence interferon γ (IFN-γ, 1.000-10.000 IU/mL) and/or triamcinolone acetonide (TA, 1 μg/mL) have on proliferation, cell viability, collagen type I synthesis, and cytokine secretion in healthy and keloid fibroblasts. It was shown that mono-treatment with IFN-γ or TA for 2 days induced a severe reduction of the proliferative potential in both cell species. The combinatory treatment (IFN-γ plus TA) of keloid fibroblasts enhanced the anti-proliferative effect of the mono-treatments, whereas no additional anti-proliferative effect was observed in normal fibroblasts. Furthermore, we observed that the combinatory treatment regimen reduced the expression of α-smooth muscle actin (α-SMA), an actin isotype contributing to cell-generated mechanical tension, in keloid fibroblasts. In normal fibroblasts, α-SMA was reduced by the mono-treatment with IFN-γ as well as by the combinatory treatment. The analysis of collagen-type I synthesis revealed that TA did not reduce collagen type I synthesis in normal fibroblasts but in keloid fibroblasts. IFN-γ reduced in both cell species the collagen type I synthesis. The combination of TA and IFN-γ intensified the previously observed collagen type I synthesis reduction in keloid fibroblasts. The herein presented data suggest the combinatory application of IFN-γ and TA as a promising therapy concept for keloids.

Gastric toxicity of Alendronate and Methotrexate in Walker 256 carcinosarcoma jaw model

Introduction: experimental animal models represent a key tool used to elucidate the mechanisms of action and toxicity of anticancer drugs. Objective: the purpose was to establish a correlation of neoplastic growth with the combinatorial therapeutic application of sodium alendronate (ALD) and methotrexate (MTX), and to evaluate the gastrointestinal toxicity of these drugs, in the rat Walker 256 carcinosarcoma inoculation model. Methods: female rats were selected and randomly distributed into 5 groups (n=10): negative control (NC), positive control (PC), MTX-treated group, ALD-treated group, and MTX-ALD-treated group (MTX/ALD). Tumor cells were inoculated as a suspension of 1x106cells/mL into the alveolar cavities produced by exodontia procedures. The following parameters were evaluated: body weight, tumor volume and percentage of tumor inhibition, and gastrointestinal toxicity. Results: the body weight variation was statistically significant between NC animals and PC animals, and between NC animals and ALD-treated group (p<0.01). Tumor volume variation was statistically significant between PC animals, MTX-treated group and MTX/ALD-co-treated group (p<0.05). Analysis of gastric toxicity of MTX-treated group reveled slight reduction of chief (Ch) and parietal (Pr) cellular populations; ALD-treated group exhibited gastric mucosa without histological alterations of Ch cells but intense reduction of Pr cellular population; and MTX/ALD-co-treated group presented reduction of Ch and Pr cellular populations. Conclusions: ALD does not elicit significant antitumor effects on Walker 256 carcinosarcoma cells and decreases antitumor effects of MTX due to toxicity on the gastric epithelium, which is intensified with MTX association.

Clustering without replication in combinatorial circuits

The modern integrated circuit is one of the most complex products engineered to date. It continues to grow in complexity as years progress. As a result, very large-scale integrated (VLSI) circuit design now involves massive design teams employing state-of-the-art computer-aided design (CAD) tools. One of the oldest, yet most important CAD problems for VLSI circuits is physical design automation, where one needs to compute the best physical layout of millions to billions of circuit components on a tiny silicon surface (Lim in Practical problems in VLSI physical design automation, Springer, Dordrecht, 2008). The process of mapping an electronic design to a chip involves several physical design stages, one of which is clustering. Even for combinatorial circuits, there exists several models for the clustering problem. In particular, we consider the problem of clustering in combinatorial circuits for delay minimization, without permitting logic replication (CN). The problem of clustering for delay minimization when logic replication is allowed (CA) has been well-studied and is known to be solvable in polynomial time (Lawler et al. in IEEE Trans Comput 18(1):47–57, 1969; Rajaraman and Wong, in: 30th ACM/IEEE design automation conference, pp 309–314, 1993). However, unbounded logic replication can be quite expensive. It follows that CN is an important problem. We show that selected variants of CN are NP-hard. We also obtain approximability and inapproximability results for some of these problems. A preliminary version of this paper appears in Donovan et al. (in: 9th International conference on combinatorial optimization and applications, COCOA 2015, Proceedings, pp 334–347, 2015).