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This paper presents a lens-free imaging approach utilizing an array of light sources, capable of measuring the dielectric properties of many particles simultaneously. This method employs coplanar electrodes to induce velocity changes in flowing particles through dielectrophoretic forces, allowing the inference of individual particle properties from differential velocity changes. Both positive and negative forces are detectable. The light source utilized in this system is composed of LEDs with a wavelength of 470 nm, while detection is performed using a 256-element optical array detector. Measurements with 10 μm polystyrene beads demonstrate this method can resolve changes equivalent to a Clausius-Mossotti factor of 0.18. Simulations in this work, using values from the literature, predict that Clausius-Mossotti factor differences of 0.18 are sufficient to differentiate viable from nonviable cells and cancerous from multidrug-resistant cancerous cells. We demonstrate that for Chinese hamster ovary (CHO) cells, the method can collect a dielectric response spectrum for a large number of cells in several minutes. We demonstrate that for CHO cells, Clausius-Mossotti factor differences of 0.18 can be discriminated. Due to its simple detection apparatus and the utilization of high-throughput, wide, clog-resistant channels, this method holds promise for a wide range of applications.

In this paper, we present a microfluidic flow cytometer for simultaneous imaging and dielectric characterization of individual biological cells within a flow. Utilizing a combination of dielectrophoresis (DEP) and high-speed imaging, this system offers a dual-modality approach to analyze both cell morphology and dielectric properties, enhancing the ability to analyze, characterize, and discriminate cells in a heterogeneous population. A high-speed camera is used to capture images of and track multiple cells in real-time as they flow through a microfluidic channel. A wide channel is used, enabling analysis of many cells in parallel. A coplanar electrode array perpendicular to cell flow is incorporated at the bottom of the channel to perform dielectrophoresis-based dielectric characterization. A frequency-dependent voltage applied to the array produces a non-uniform electric field, translating cells to higher or lower velocity depending on their dielectric polarizability. In this paper, we demonstrate how cell size, obtained by optical imaging, and DEP response, obtained by particle tracking, can be used to discriminate viable and non-viable Chinese hamster ovary cells in a heterogeneous cell culture. Multiphysics electrostatic-fluid dynamics simulation is used to develop a relationship between cell incoming velocity, differential velocity, size, and the cell's polarizability, which can subsequently be used to evaluate its physiological state. Measurement of a mixture of polystyrene microspheres is used to evaluate the accuracy of the cytometer.

Background Pre-exposure prophylaxis (PrEP) use has been attributed to heightened rates of sexually transmitted infections (STIs), ostensibly due to increased condomless anal sex (CAS) and greater frequency of STI testing. Few qualitative studies have assessed how gay, bisexual and queer men (GBQM) who use PrEP perceive STIs and how these attitudes have evolved post-PrEP uptake. We investigated the perspectives of current and former PrEP users on STIs. Methods Annual, in-depth longitudinal interviews were conducted with 38 current and former PrEP users in Ontario (n =18) and British Columbia (n =20), Canada, as part of a mixed-methods implementation science study (2020-2022). Over 3years, 109 interviews were conducted. Data analysis included reflexive thematic coding and longitudinal recurrent cross-sectional analysis using NVivo 12. Results Four STI-related themes emerged: (1) lack of STI-related concerns due to treatment and prevention optimism, (2) stigma-related concerns, (3) perceived risk among other PrEP users due to increased CAS, and (4) inconsistent testing concerns among non-PrEP users. Over time, some STI-related anxieties decreased with increased knowledge and reduced stigma. However, concerns persisted for other participants due to perceived risky sexual behaviours among other PrEP users and non-PrEP users. Both current and former PrEP users who expressed STI-related apprehensions consistently indicated adopting risk-reduction strategies, including condom use and having fewer sexual partners throughout the study. Conclusions Findings show how varied STI perceptions and experiences among current and former PrEP users shaped sexual decision-making over time. Providers, public health experts, and policymakers should develop a more comprehensive strategy to address STI concerns among GBQM.

Background: HIV pre-exposure prophylaxis (PrEP) is a highly effective biomedical intervention used by HIV-negative people to prevent HIV acquisition. Despite increased use of PrEP worldwide, several barriers to PrEP implementation have resulted in insufficient uptake, inadequate adherence, and frequent discontinuation. Our objective was to interrogate the social, political, and economic conditions shaping PrEP implementation and delivery among gay, bisexual, queer and other men who have sex with men (GBQM) in Ontario, Canada., Methods: Six focus groups and three interviews with 20 stakeholders in Ontario (e.g., healthcare professionals, clinicians, community-based organization staff, and government staff) were conducted between July and October 2021. Participants were asked about the personal, workplace, and structural factors shaping PrEP delivery strategies for GBQM. Transcripts were analyzed using reflexive thematic analysis informed by the political economy of PrEP and employed a critique of neoliberalism., Results: Participants critiqued the problematic arrangements of the current healthcare system in Canada. Neoliberal governmentality and policies have resulted in inequitable PrEP care by establishing funding structures prioritizing profit and requiring patients and providers to function as individual entrepreneurs. Consequently, healthcare disparities are compounded for marginalized peoples who lack the resources and capacity to navigate existing healthcare systems. Participants identified several pathways to improve the implementation of PrEP, including greater institutional and governmental supports for PrEP and healthcare, leveraging communities and collaboration, and moving beyond risk-based health frameworks., Conclusion: Socio-political-economic changes reflecting post-neoliberal principles are needed to overcome existing barriers to PrEP care, and sexual and reproductive healthcare more broadly., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

The COVID-19 pandemic led to the widespread adoption of virtual care-the use of communication technologies to receive health care at home. We explored the differential impacts of the rapid transition to virtual care during the COVID-19 pandemic on health-care access and delivery for gay, bisexual and queer men (GBQM), a population that disproportionately experiences sexual and mental health disparities in Canada. Adopting a sociomaterial theoretical perspective, we analysed 93 semi-structured interviews with GBQM (n = 93) in Montreal, Toronto and Vancouver, Canada, conducted between November 2020 and February 2021 (n = 42) and June-October 2021 (n = 51). We focused on explicating how the dynamic relations of humans and non-humans in everyday virtual care practices have opened or foreclosed different care capacities for GBQM. Our analysis revealed that the rapid expansion and implementation of virtual care during the COVID-19 pandemic enacted disruptions and challenges while providing benefits to health-care access among some GBQM. Further, virtual care required participants to change their sociomaterial practices to receive health care effectively, including learning new ways of communicating with providers. Our sociomaterial analysis provides a framework that helps identify what works and what needs to be improved when delivering virtual care to meet the health needs of GBQM and other diverse populations., (© 2023 The Authors. Sociology of Health & Illness published by John Wiley & Sons Ltd on behalf of Foundation for the Sociology of Health & Illness.)

In efforts to prevent the spread of COVID-19, jurisdictions across the globe, including Canada, enacted containment measures that affected intimacy and sexual relations. This article examines how public health measures during COVID-19 impacted the sexual practices of sexual minority men- gay, bisexual, queer and other men who have sex with men-and how they adopted and modified guidelines to prevent the transmission of COVID-19, HIV and other sexually transmitted infections (STIs). We conducted 93 semi-structured interviews with men ( n  = 93) in Montreal, Toronto and Vancouver, Canada, between November 2020 to February 2021 ( n  = 42) and June to October 2021 ( n  = 51). Across jurisdictions, participants reported changes to sexual practices in response to public health measures and shifting pandemic contexts. Many men indicated that they applied their HIV/STI risk mitigation experiences and adapted COVID-19 prevention strategies to continue engaging in casual sexual behaviours and ensure sexual safety. 'Social bubbles' were changed to 'sex bubbles'. Masks were turned into 'safer' sex tools. 'Outdoor gathering' and 'physical distancing' were transformed into 'outdoor sex' and 'voyeuristic masturbation'. These strategies are examined in connection to the notion of 'reflexive mediation' to illustrate how sexual minority men are simultaneously self-responsibilising and resistant, self-monitoring and creative.

Objective: Epidemics impact individuals unevenly across race, gender, and sexuality. In addition to being more vulnerable to COVID-19 infection, evidence suggests racialized gender and sexual minorities experienced disproportionate levels of discrimination and stigma during the COVID-19 epidemic. Drawing on Critical Race Theory (CRT), we examined the experiences of gay, bisexual, queer, and other men who have sex with men (GBQM) of colour facing discrimination during COVID-19., Design: Engage-COVID-19 is a mixed methods study examining the impact of COVID-19 on GBQM living in Vancouver, Toronto, and Montréal, Canada. We conducted two rounds of qualitative interviews (November 2020 to February 2021, and June to October 2021) with 93 GBQM to explore the evolving impact of COVID-19 on their lives. Transcripts were coded using inductive thematic analysis. Data analysis was conducted using Nvivo software., Results: Fifty-nine participants identified as Black, Indigenous, and/or a Person of Colour (BIPOC). These GBQM of colour described multiple experiences of discrimination during COVID-19. Although participants did not report experiences of discrimination based on their sexual identity during COVID-19, we found that experiences of racism affected how they were treated within their sexual networks. Experiences of racism were most often reported by East Asian and Black GBQM. These participants faced racism in public and online spaces, primarily in the form of verbal harassment. Several participants were also harassed because they wore face masks. Verbal abuse against GBQM of colour was largely prompted by racist discourses related to COVID-19., Conclusion: Racism remains a pernicious threat to the well-being of GBQM of colour. CRT highlights the importance of assessing how sexualized and gendered discourses about race shape the experiences of GBQM of colour navigating multiple epidemics like COVID-19 and HIV. These pervasive discourses unevenly affect racial and sexual minorities across multiple epidemics, and negatively impact health outcomes for these populations., (© 2023. BioMed Central Ltd., part of Springer Nature.)

Background: Our objective was to understand what gay, bisexual, and queer men (GBQM) who had experience using pre-exposure prophylaxis (PrEP) thought about the 'Undetectable equals Untransmittable' (U=U) message and how it informed their sexual decision-making over time., Methods: We conducted annual longitudinal qualitative interviews (2020-22) with 17 current or former PrEP users as part of a mixed-methods implementation science study examining barriers and facilitators to PrEP awareness, access, and adherence. Over 3years, 47 interviews were conducted with GBQM in Ontario, Canada. Interviews were transcribed verbatim and coded in NVivo following reflexive thematic analysis., Results: Participants' sexual health decision-making was informed by their confidence in biomedical HIV prevention and the person taking medication (i.e. themselves using PrEP versus a real/imagined person living with HIV (PLHIV)). Longitudinal narratives of U=U clustered around four overarching themes: (1) U=U confidence (i.e. increasing trust in U=U irrespective of their PrEP use); (2) PrEP confidence (i.e. accounts of self-reliance and PrEP as sufficient HIV protection); (3) combination confidence (i.e. trusting U=U and PrEP as a package); and (4) partner confidence (i.e. potential 'distrust' of U=U due to uncertainties about partners' medication adherence). Overall, men described increased sex with PLHIV over time, including some participants who, during earlier interviews, said they would 'never be comfortable' with serodifferent sexual partners., Conclusions: GBQM's use of PrEP shaped how they thought about U=U and sex with PLHIV. Although many GBQM embraced treatment as prevention/U=U as significant to their sexual lives, longitudinal analysis revealed its varied and uneven adoption across participants and time.

One hope surrounding long-acting HIV pre-exposure prophylaxis (PrEP) is reaching new users who could most benefit, as well as improving the experiences of oral PrEP users who may desire to switch modalities. Gay, bisexual, queer, and other men who have sex with men (GBQM) continue to make up over half of new HIV diagnoses in Canada, and oral PrEP uptake has plateaued among this population. Approval of injectable PrEP is anticipated, but there is a paucity of research to inform health promotion and implementation. Between June and October 2021, we conducted 22 in-depth interviews with GBQM oral PrEP users and non-PrEP users living in Ontario, Canada. We also conducted small focus groups or individual interviews with 20 key stakeholders (health care providers, public health officials, community-based organization staff). Interviews were audio recorded, transcribed verbatim, and analyzed in NVivo using thematic analysis. Only about one-third of GBQM had heard of injectable PrEP. Many PrEP users perceived greater convenience, adherence, and confidentiality with injectable PrEP. Some PrEP users did not anticipate switching because of needle discomfort or feeling more "in control" with oral PrEP. None of the non-PrEP users said that injectable PrEP would make them start PrEP. Injectable PrEP may offer additional convenience for GBQM; however, it did not appear to affect participants' PrEP decision-making significantly. Stakeholders noted that injectable PrEP may improve access, support adherence, and benefit marginalized groups. Some clinicians expressed concerns about the time/personnel required to make injectable PrEP available. System-level challenges in implementing injectable PrEP, including cost, must also be addressed.

There are many reasons why individuals engage in prosocial behavior; communal sexual altruism is based on the notion that some practice safer sex in the interest of promoting the well-being of their community/in-group. Given that definitions of what constitutes "safer sex" have changed with advances in human immunodeficiency virus (HIV) prevention, we investigated the importance of communal sexual altruism (herein "altruism") among urban gay, bisexual, and other sexual minority men (GBM) in the contemporary context. Using a sample of 2449 GBM we examined the association of both safer-sex-related attitudes (e.g., HIV treatment optimism-skepticism) and behaviors (e.g., condomless anal sex [CAS]) with altruism scores. Higher altruism scores were associated with a lower likelihood of CAS and a greater frequency of discussing HIV status with new partners. These findings demonstrate that many GBM are motivated to engage in several kinds of behaviors that improve the well-being of their in-group (i.e., the GBM community)., (© 2022 Wiley Periodicals LLC.)

Epigenetic modifiers of the histone deacetylase (HDAC) family contribute to autoimmunity, cancer, HIV infection, inflammation, and neurodegeneration. Hence, histone deacetylase inhibitors (HDACi), which alter protein acetylation, gene expression patterns, and cell fate decisions, represent promising new drugs for the therapy of these diseases. Whereas pan-HDACi inhibit all 11 Zn 2+ -dependent histone deacetylases (HDACs) and cause a broad spectrum of side effects, specific inhibitors of histone deacetylase 6 (HDAC6i) are supposed to have less side effects. We present the synthesis and biological evaluation of Marbostats, novel HDAC6i that contain the hydroxamic acid moiety linked to tetrahydro-β-carboline derivatives. Our lead compound Marbostat-100 is a more potent and more selective HDAC6i than previously established well-characterized compounds in vitro as well as in cells. Moreover, Marbostat-100 is well tolerated by mice and effective against collagen type II induced arthritis. Thus, Marbostat-100 represents a most selective known HDAC6i and the possibility for clinical evaluation of a HDAC isoform-specific drug.

Legionella pneumophila is an intracellularly surviving pathogen that releases about 270 different proteins into the host cell during infection. A set of secreted proteins takes control of the vesicular trafficking regulator Rab1. Legionella LepB inactivates Rab1 by acting as a GTPase-activating protein (GAP). We present the crystal structure of the Rab1b:LepB complex together with a thorough biochemical analysis and show that the GAP domain of LepB consists of an unusual fold. LepB acts by an atypical RabGAP mechanism that is reminiscent of classical GAPs and therefore sets the protein apart from mammalian TBC-like GAPs. Surprisingly, LepB can function as a GAP for Rab3, Rab8, Rab13 and Rab35, too, suggesting that it has a broader cellular role than previously thought.

Pathological processing of tau protein during the formation and maturation of neurofibrillary tangles (NFTs) includes abnormal phosphorylation, conformational changes and truncation of the C-terminus at aspartic-acid(421) (apoptotic product) and glutamic-acid(391) residues. Abnormal phosphorylation and misfolding may serve as recognition signals for ubiquitin-targeting and proteosomal processing. For this reason, we sought to determine whether ubiquitin-targeting of tau is associated with particular tau modifications that herald specific stages of NFTs maturation in the hippocampus of Alzheimer's disease cases. Using multiple tau antibodies, we found that 30% of the total load of NFTs is ubiquitin-associated. As reported previously ubiquitin immunoreactivity was associated with markers of phosphorylated tau in certain NFTs; however, a strong association was also found between ubiquitin and the earliest known truncation event at aspartic-acid(421) . These findings indicate that tau protein in the NFTs may be dually subjected to both apoptotic and proteosomal processing. By contrast ubiquitin immunoreactivity was poorly associated with truncation of tau at glutamic-acid(391) , suggesting that this proteolytic event may be independent of proteosomal activity. It would appear, therefore, that ubiquitin targeting of tau protein occurs at NFTs in the early and intermediate stages of the maturation., (© 2011 The Authors. Brain Pathology © 2011 International Society of Neuropathology.)

Several members of the quinazoline class of known tyrosine kinase inhibitors are approved anticancer agents, often showing selectivity for receptors of the HER/ErbB-family. Combining structural elements of this class with the bisindolylmethanone-structure led to a series of novel compounds. These compounds inhibited EGFR in the nanomolar range. Moreover, inhibition of EGFR autophosphorylation in intact A431 cells was shown, with IC(50) values ranging form 0.3-1μM for compound 42, and 0.1-0.3μM for 45. In a panel of 42 human tumor cell lines the sensitivity profile of the novel compounds was shown to be similar to that of the quinazoline class of tyrosine kinase inhibitors lapatinib and erlotinib (Tarceva®)., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Reversible lysine-specific acetylation has been described as an important posttranslational modification, regulating chromatin structure and transcriptional activity in the case of core histone proteins. Histone deacetylases (HDAC) are considered as a promising target for anticancer drug development, with 2a as pan-HDAC inhibitor approved for cutanous T-cell lymphoma therapy and several other HDAC inhibitors currently in preclinical and clinical development. Protein kinases are a well-established target for cancer therapy with the EGFR/HER2 inhibitor 5 approved for treatment of advanced, HER2 positive breast cancer as a prominent example. In the present report, we present a novel strategy for cancer drug development by combination of EGFR/HER2 kinase and HDAC inhibitory activity in one molecule. By combining the structural features of 5 with an (E)-3-(aryl)-N-hydroxyacrylamide motif known from HDAC inhibitors like 1 or 3, we obtained selective inhibitors for both targets with potent cellular activity (target inhibition and cytotoxicity) of selected compounds 6a and 6c. By combining two distinct pharmacologically properties in one molecule, we postulate a broader activity spectrum and less likelihood of drug resistance in cancer patients.

In animals, visual pigments are essential for photoreceptor function and survival. These G-protein-coupled receptors consist of a protein moiety (opsin) and a covalently bound 11-cis-retinylidene chromophore. The chromophore is derived from dietary carotenoids by oxidative cleavage and trans-to-cis isomerization of double bonds. In vertebrates, the necessary chemical transformations are catalyzed by two distinct but structurally related enzymes, the carotenoid oxygenase beta-carotenoid-15,15'-monooxygenase and the retinoid isomerase RPE65 (retinal pigment epithelium protein of 65 kDa). Recently, we provided biochemical evidence that these reactions in insects are catalyzed by a single enzyme family member named NinaB. Here we show that in the fly pathway, carotenoids are mandatory precursors of the chromophore. After chromophore formation, the retinoid-binding protein Pinta acts downstream of NinaB and is required to supply photoreceptors with chromophore. Like ninaE encoding the opsin, ninaB expression is eye-dependent and is activated as a downstream target of the eyeless/pax6 and sine oculis master control genes for eye development. The requirement for coordinated synthesis of chromophore and opsin is evidenced by analysis of ninaE mutants. Retinal degeneration in opsin-deficient photoreceptors is caused by the chromophore and can be prevented by restricting its supply as seen in an opsin and chromophore-deficient double mutant. Thus, our study identifies NinaB as a key component for visual pigment production and provides evidence that chromophore in opsin-deficient photoreceptors can elicit retinal degeneration.

Inhibitors of histone deacetylases are a new class of cancer therapeutics with possibly broad applicability. Combinations of HDAC inhibitors with the kinase inhibitor 1 (Imatinib) in recent studies showed additive and synergistic effects. Here we present a new concept by combining inhibition of protein kinases and HDACs, two independent pharmacological activities, in one synthetic small molecule. In general, the HDAC inhibition profile, the potencies, and the probable binding modes to HDAC1 and HDAC6 were similar as for 6 (SAHA). Inhibition of Abl kinase in biochemical assays was maintained for most compounds, but in general the kinase selectivity profile differed from that of 1 with nearly equipotent inhibition of the wild-type and the Imatinib resistant Abl T(315)I mutant. A potent cellular inhibition of PDGFR and cytotoxicity toward EOL-1 cells, a model for idiopathic hypereosinophilic syndrome (HES), are restored or enhanced for selected analogues (12b, 14b, and 18b). Cytotoxicity was evaluated by using a broad panel of tumor cell lines, with selected analogues displaying mean IC(50) values between 3.6 and 7.1 muM.

Investigations of alterations in brain asymmetry often focus on the planum temporale of patients with schizophrenia. Data also suggest changes in laterality of demented patients associated with a more marked impairment of the left hemisphere. Our study was performed on autoptic brain tissue of 84 patients, out of which there were 25 non-demented non-psychotic controls, 50 demented patients (34 Alzheimer disease, 9 multi - infarct dementia and 7 mixed-type dementia patients) and 9 people with schizophrenia. The plana temporalia were evaluated via a new volumetric method using dental resin matter. Areas, cortical thickness and volumes of the right and left planum temporale were evaluated without normalization to brain weight in 60 patients and with normalization in 24 people. In controls, a mild right/left laterality of areas, cortical thickness and volumes was found. Moreover, in control women the areas of the left planum temporale were smaller than those observed in control men. The shifts to left/right laterality of areas and volumes were found in all demented groups. In the more numerous Alzheimer group, the change in laterality of an area was associated with a mild decrease on the right and a mild increase on the left side. In contrast, marked but only bilateral area shrinkage as well as reduced cortical thickness and brain volumes were observed in schizophrenic patients.

The aim of the study was to discuss the case of Krukenberg tumor in a patient, eight years after the diagnosis and surgical treatment of gastric carcinoma. We have concluded that there was no safe period after which distant metastases may be excluded. In case of gastric carcinoma diagnosed in women, a regular gynecological examination is necessary due to a high propability of metastases into ovaries, even if the clinical stage of gastric carcinoma is low.

Benzene, a tobacco constituent, is a leukemogen in humans and a carcinogen in rodents. Several benzene metabolites generate superoxide anion (O(2)(.-)) and induce nitric oxide synthase in the bone marrow of mice. We hypothesized that the reaction of nitric oxide (*NO) with O(2)(.-) leads to the formation of peroxynitrite as an intermediate during benzene metabolism. This hypothesis was supported by demonstrating that the exposure of mice to benzene produced nitrated metabolites and enhanced the levels of protein-bound 3-nitrotyrosine in the bone marrow of mice in vivo. In the current study, we investigated the influence of nitric oxide, generated from sodium 1-(N,N-diethylamino)diazen-1-ium-1,2-diolate, on DNA strand breaks induced by each single or binary benzene metabolite at different doses and compared the levels of the DNA damage induced by each benzene metabolite in the presence of nitric oxide with the levels of DNA strand breaks induced by peroxynitrite at similar doses in vitro. We found that among benzene metabolites only 1,2,4-trihydroxybenzene (BT) can induce significant DNA damage in the absence of nitric oxide. While 1,4-dihydroxybenzene (HQ), 1,4-benzoquinone (BQ) and 1,2-dihydroxybenzene (CAT) require .NO to induce DNA strand breaks, hydroquinone was the most potent DNA-damaging benzene metabolite in the presence of *NO. The order of DNA breaks by benzene metabolites in the presence of *NO is: Peroxynitrite = HQ > BT > BQ > CAT. The *NO and O(2)(.-) scavengers inhibited DNA damage induced by [HQ+*NO]. Benzene, trans,trans-muconaldehyde, and phenol, do not induce DNA strand breaks either in the absence or presence of *NO. However, adding phenol to [HQ+*NO] leads to greater DNA damage than [HQ+*NO] alone. Collectively, these results suggest that nitric oxide is an important factor in DNA damage induced by certain benzene metabolites, probably via the formation of the peroxynitrite intermediate. Phenol, the major benzene metabolite that does not induce DNA damage alone and is inactive in vivo, synergistically enhances DNA damage induced by potent benzene metabolite in the presence of nitric oxide.

Compounds containing 3-bromo-2,5-dihydro-1H-2,5-pyrroledione and indole substructures were found to have antibacterial activity against resistant strains of Staphylococcus aureus and some other Gram positive bacteria. The investigated compounds exhibit minimal inhibition concentrations (MICs) lower than those of common antibiotics like vancomycin or ciprofloxacin. Activity against multiresistant strains suggests a mechanism of action different from common antibiotics. This might be important in circumventing existing resistance mechanisms. Here we report about the antibacterial activity in an extended structure-activity relationship study.

Objective: The multifunctional mitochondrial enzyme 17beta-hydroxysteroid dehydrogenase type 10 could play a role in the development of Alzheimer disease via its high-affinity binding to amyloid-beta peptides and its overexpression., Methods: We evaluated the specificity of alterations in mRNA/enzyme expression levels in human right and left hippocampi., Results: We observed a trend towards right/left laterality in nondemented nonpsychotic controls; however, the degree of asymmetry was higher for mRNA when compared to enzyme expression levels. In Alzheimer disease and schizophrenia, significant shifts to left/right asymmetry were found and the changes were associated with more marked increases in mRNA/enzyme expression in the left hemisphere. On the other hand, no alterations were observed in people with multi-infarct dementia., Conclusion: Our results support studies reporting an impairment of mitochondria in Alzheimer disease or schizophrenia and a higher vulnerability of the dominant hemisphere to pathological processes. Overexpression of the enzyme could be used to distinguish Alzheimer disease from multi-infarct dementia., (Copyright 2008 S. Karger AG, Basel.)

A series of bis(benzo[b]furan-2-yl)methanones was synthesized and tested for inhibition of FLT3 and PDGFR autophosphorylation. Mostly, C-5 substitution leads to PDGFR selectivity, which was strongest in the case of the 5,5'-dimethoxy derivative. The 5,5'-diamino and the 6,6'-dihydroxy compounds are more active at FLT3. At both kinases, the potency of the best inhibitors approaches IC50 values of ca. 0.5 microM. Molecular modeling studies suggest that the bisbenzofuranylmethanones are able to fit into the same binding site as their indolyl analogues which have been suggested to form a bidentate hydrogen bridge with the backbone in the hinge regions. The loss of one H bond by the NH-O exchange might be partially compensated by, for example, the weak interaction of one furanyl oxygen with FLT3 Cys-828.

Synthesis and cytotoxic activity in the submicromolar range of a series of [4-(imidazol-1-yl)thiazol-2-yl]phenylamines are described. Cell cycle dependent cytotoxicity on RKO human colon carcinoma cells with inducible expression of p27(kip1) and the influence on microtubule formation were investigated. Considering the significant correlation between the IC(50) values of tubulin polymerization inhibition, [(3)H]colchicine competition, and cytotoxicity of the investigated compounds, tubulin is the main cellular target. The inhibition of microtubule formation was shown to be mediated by interference with the colchicine binding site of tubulin. In depth analysis of the investigated compounds allowed the identification of modifications that altered the pharmacological profile of the compounds from a mitosis-inducing phenotype to a G1 cell cycle arresting phenotype.

FLT3 receptor tyrosine kinase is aberrantly active in many cases of acute myeloid leukemia (AML). Recently, bis(1H-indol-2-yl)methanones were found to inhibit FLT3 and PDGFR kinases. To optimize FLT3 activity and selectivity, 35 novel derivatives were synthesized and tested for inhibition of FLT3 and PDGFR autophosphorylation. The most potent FLT3 inhibitors 98 and 102 show IC50 values of 0.06 and 0.04 microM, respectively, and 1 order of magnitude lower PDGFR inhibiting activity. The derivatives 76 and 82 are 20- to 40-fold PDGFR selective. Docking at the recent FLT3 structure suggests a bidentate binding mode with the backbone of Cys-694. Activity and selectivity can be related to interactions of one indole moiety with a hydrophobic pocket including Phe-691, the only different binding site residue (PDGFR Thr-681). Compound 102 inhibited the proliferation of 32D cells expressing wildtype FLT3 or FLT3-ITD similarly as FLT3 autophosphorylation, and induced apoptosis in primary AML patient blasts.

A number of new compounds containing 3-bromo-2,5-dihydro-1H-2,5-pyrroledione and indole substructures were found to have antibacterial activity against resistant strains of Staphylococcus aureus, Mycobacterium smegmatis and some other Gram positive bacteria. The investigated compounds exhibit minimal inhibition concentrations (MIC's) lower than those of ciprofloxacin, vancomycin and doxycycline resp. A different spectrum of activity, suggests a mechanism of action different to vancomycin and doxycycline. This might be important in circumventing existing resistance mechanisms. Here we report about the synthesis and on the antibacterial activity in a structure activity relationship study.

Repetitive elements represent a large portion of the human genome and contain much of the CpG methylation found in normal human postnatal somatic tissues. Loss of DNA methylation in these sequences might account for most of the global hypomethylation that characterizes a large percentage of human cancers that have been studied. There is widespread interest in correlating the genomic 5-methylcytosine content with clinical outcome, dietary history, lifestyle, etc. However, a high-throughput, accurate and easily accessible technique that can be applied even to paraffin-embedded tissue DNA is not yet available. Here, we report the development of quantitative MethyLight assays to determine the levels of methylated and unmethylated repeats, namely, Alu and LINE-1 sequences and the centromeric satellite alpha (Satalpha) and juxtacentromeric satellite 2 (Sat2) DNA sequences. Methylation levels of Alu, Sat2 and LINE-1 repeats were significantly associated with global DNA methylation, as measured by high performance liquid chromatography, and the combined measurements of Alu and Sat2 methylation were highly correlative with global DNA methylation measurements. These MethyLight assays rely only on real-time PCR and provide surrogate markers for global DNA methylation analysis. We also describe a novel design strategy for the development of methylation-independent MethyLight control reactions based on Alu sequences depleted of CpG dinucleotides by evolutionary deamination on one strand. We show that one such Alu-based reaction provides a greatly improved detection of DNA for normalization in MethyLight applications and is less susceptible to normalization errors caused by cancer-associated aneuploidy and copy number changes.

The BAGE (B melanoma antigens) sequence family contains 15 nearly identical sequences that are in the juxtacentromeric regions of chromosomes 9, 13, 18, and 21. BAGE loci are expressed in male germ tissue and in a high percentage of cancers and cancer cell lines. We analyzed the DNA methylation state of the sequences in or near the promoters of the BAGE loci by a quantitative bisulfite and PCR-based assay (multiplex COBRA) using MboI and HphI in 18 somatic tissue samples, 4 testis and 4 sperm samples, and 48 tumors and tumor cell lines. In 94% of the control somatic tissue samples, DNA was highly methylated in the analyzed regions. In contrast, 98% of tumor DNA samples displayed hypomethylation. Also, DNA from testes and sperm was hypomethylated in at least one of the BAGE loci. BAGE transcripts were observed in only 47% of the analyzed tumor samples. Consequently, we propose BAGE hypomethylation as a new, highly informative epigenetic biomarker for the diagnosis of cancer, whose hypomethylation in cancer may be causally related to that of juxtacentromeric satellite DNA., (Copyright 2005 Wiley-Liss, Inc.)

Synthesis and cytotoxic activity of a series of 2-acyl-1H-indole-4,7-diones on human cancer cell lines are described. Due to close structural relationship to 2-acylindoles, potent inhibitors of tubulin polymerization, the mode of action of these novel compounds has been investigated. Cytotoxicity, the influence on tubulin polymerization, and cell cycle dependent cytotoxicity on colon carcinoma cells by investigation of RKO exo p27 versus RKO p27(kip1) cells are described. IC50 values of arrested versus proliferating cells differ only in a range of two to fourfold and therefore cellular targets, predominantly relevant for mitotic progression, are excluded. As shown by the significant difference in the IC90 values on different tumor cell lines, the investigated compounds seem to act selectively on mammary and renal cancer cells.

Hypomethylation of some portions of the genome and hypermethylation of others are very frequent attributes of human cancer. We previously showed that cancer-associated DNA hypomethylation often involves satellite 2 (Sat2), the main DNA component of the large juxtacentromeric (centromere-adjacent) heterochromatin of chromosome 1. In this study, we compared methylation of Sat2 and centromeric satellite DNA (Satalpha) as well as overall genomic methylation in 41 breast adenocarcinomas of known tumor grade and stage, 16 non-neoplastic breast tissues (mostly fibroadenomas), and a variety of normal somatic tissue controls. The cancers were significantly hypomethylated at Sat2 relative to the fibroadenomas or normal somatic tissues and at Satalpha relative to the normal somatic tissues. However, unlike Sat2, Satalpha did not display significant differences in methylation between the cancers and the non-neoplastic breast tissues. Therefore, hypomethylation at Sat2 is a much better marker of breast cancer than is Satalpha hypomethylation. There was a significant association of Sat2 hypomethylation with global DNA hypomethylation in the cancers but not with tumor grade, stage, axillary lymph node involvement, or hormone receptor status. Extensive cancer-associated hypomethylation of juxtacentromeric satellite DNA and global DNA hypomethylation were common even in grade-1 or stage-1 carcinomas, which suggests that demethylation of the genome is an early event in breast carcinogenesis.

We quantitatively analysed hypermethylation at CpG islands in the 5' ends of 12 genes and one non-CpG island 5' region (MTHFR) in 31 Wilms tumors. We also determined their global genomic 5-methylcytosine content. Compared with various normal postnatal tissues, approximately 40-90% of these pediatric kidney cancers were hypermethylated in four of the genes, MCJ, RASSF1A, TNFRSF12 and CALCA as determined by a quantitative bisulfite-based assay (MethyLight). Interestingly, the non-CpG island 5' region of MTHFR was less methylated in most tumors relative to the normal tissues. By chromatographic analysis of DNA digested to deoxynucleosides, about 60% of the Wilms tumors were found to be deficient in their overall levels of DNA methylation. We also analysed expression of the three known functional DNA methyltransferase genes. No relationship was observed between global genomic 5-methylcytosine levels and relative amounts of RNA for DNA methyltransferases DNMT1, DNMT3A, and DNMT3B. Importantly, no association was seen between CpG island hypermethylation and global DNA hypomethylation in these cancers. Therefore, the overall genomic hypomethylation frequently observed in cancers is probably not just a response or a prelude to hypermethylation elsewhere in the genome. This suggests that the DNA hypomethylation contributes independently to oncogenesis or tumor progression.

Carotenoids are currently being intensely investigated regarding their potential to lower the risk of chronic disease and vitamin A deficiency. Invertebrate models in which vitamin A deficiency is not lethal allow the isolation of blind but viable mutants affected in the pathway leading from dietary carotenoids to vitamin A. Using a mutant in one of these model systems, Drosophila, the vitamin A-forming enzyme has recently been molecularly identified. We now show that the molecular basis for the blindness of a different Drosophila mutant, ninaD, is a defect in the cellular uptake of carotenoids. The ninaD gene encodes a class B scavenger receptor essential for the formation of the visual chromophore. A loss of this function results in a carotenoid-free and thus vitamin A-deficient phenotype. Our investigations provide molecular insight into how carotenoids may be distributed into cells of target tissues in animals and indicate a crucial role of class B scavenger receptors rendering dietary carotenoids available for subsequent cell metabolism, as needed for their various physiological functions.

Redox and ligand exchange reactions of the oxygenation catalyst (N,N '-bis(salicylidene)ethylenediaminato)cobalt(II), Co(salen), and its one-electron oxidation product, Co(salen)(+), are investigated in DMF, pyridine, and mixtures of these solvents. Electron transfers and solvent exchange reactions involving three neutral Co(II) and three cationic Co(III) complexes with different axially bound solvent molecules (two DMF, one DMF and one pyridine, or two pyridine molecules) form a three-rung ladder scheme. All formal potentials E(0) and equilibrium constants K in this scheme are determined from electrochemical or spectrophotometric experiments or the construction of thermodynamic cycles. The latter are also used to prove consistency of the results. Values for the E(0) and K are discussed in terms of the Co coordination geometry, solvent effects on the potentials, the thermodynamics of cross reactions, and the distribution of Co(II) and Co(III) species as a function of the solvent composition. Some peculiarities found in the oxygenation of flavonols and indoles are explained.