363 research outputs found

    Synthesis and Anti-Mycobacterium tuberculosis Activity of Imidazo[2,1-b][1,3]oxazine Derivatives against Multidrug-Resistant Strains

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    The emergence of multidrug-resistant strains of M. tuberculosis has raised concerns due to the greater difficulties in patient treatment and higher mortality rates. Herein, we revisited the 2-nitro-6,7-dihydro-5H-imidazo[2,1-b][1,3]oxazine scaffold and identified potent new carbamate derivatives having MIC90 values of 0.18–1.63 μM against Mtb H37Rv. Compounds 47–49, 51–53, and 55 exhibited remarkable activity against a panel of clinical isolates, displaying MIC90 values below 0.5 μM. In Mtb-infected macrophages, several compounds demonstrated a 1-log greater reduction in mycobacterial burden than rifampicin and pretomanid. The compounds tested did not exhibit significant cytotoxicity against three cell lines or any toxicity to Galleria mellonella. Furthermore, the imidazo[2,1-b][1,3]oxazine derivatives did not show substantial activity against other bacteria or fungi. Finally, molecular docking studies revealed that the new compounds could interact with the deazaflavin-dependent nitroreductase (Ddn) in a similar manner to pretomanid. Collectively, our findings highlight the chemical universe of imidazo[2,1-b][1,3]oxazines and their promising potential against MDR-TB

    Changes in the Adhesive Properties of Spider Aggregate Glue During the Evolution of Cobwebs

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    We compare the prey capture glues produced by orb-weaving spiders (viscid glue) and their evolutionary descendents, the cobweb-weaving spiders (gumfoot glue). These glues are produced in homologous glands but exhibit contrasting structure, properties and response to changing humidity. Individual glue droplet stretching measurements indicate that the gumfoot glue behaves like a viscoelastic liquid in contrast to the viscid glue, which behaves like a viscoelastic solid. Moreover, the gumfoot glue is largely humidity-resistant – elasticity and adhesion are constant across variation in humidity and there is weak volume-dependence. Viscid glue, however, is highly humidity-sensitive. The glue expands an order of magnitude and demonstrates a monotonous reduction in elasticity under increased humidity, while glue adhesion optimizes at intermediate levels of humidity. We suggest that observed differences are due to different ‘tackifiers' used in these systems. These results shall inspire future efforts in fabricating stimuli-resistant and stimuli-sensitive materials

    Localization of AQP5 during development of the mouse submandibular salivary gland

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    Aquaporin 5 (AQP5) is known to be central for salivary fluid secretion. A study of the temporal-spatial distribution of AQP5 during submandibular gland (SMG) development and in adult tissues might offer further clues to its unknown role during development. In the present work, SMGs from embryonic day (E) 14.5–18.5 and postnatal days (P) 0, 2, 5, 25, and 60 were immunostained for AQP5 and analyzed using light microscopy. Additional confocal and transmission electron microscopy were performed on P60 glands. Our results show that AQP5 expression first occurs in a scattered pattern in the late canalicular stage and becomes more prominent and organized in the terminal tubuli/pro-acinar cells towards birth. Additional apical membrane staining in the entire intralobular duct is found just prior to birth. During postnatal development, AQP5 is expressed in both the luminal and lateral membrane of pro-acinar/acinar cells. AQP5 is also detected in the basal membrane of acinar cells at P25 and P60. In the intercalated ducts at P60, the male glands show apical staining in the entire segment, while only the proximal region is positive in the female glands. These results demonstrate an evolving distribution of AQP5 during pre- and postnatal development in the mouse SMGs

    Modeling flow cytometry data for cancer vaccine immune monitoring

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    Flow cytometry (FCM) is widely used in cancer research for diagnosis, detection of minimal residual disease, as well as immune monitoring and profiling following immunotherapy. In all these applications, the challenge is to detect extremely rare cell subsets while avoiding spurious positive events. To achieve this objective, it helps to be able to analyze FCM data using multiple markers simultaneously, since the additional information provided often helps to minimize the number of false positive and false negative events, hence increasing both sensitivity and specificity. However, with manual gating, at most two markers can be examined in a single dot plot, and a sequential strategy is often used. As the sequential strategy discards events that fall outside preceding gates at each stage, the effectiveness of the strategy is difficult to evaluate without laborious and painstaking back-gating. Model-based analysis is a promising computational technique that works using information from all marker dimensions simultaneously, and offers an alternative approach to flow analysis that can usefully complement manual gating in the design of optimal gating strategies. Results from model-based analysis will be illustrated with examples from FCM assays commonly used in cancer immunotherapy laboratories

    The levels of anti-HPV16/18 and anti-HPV31/33/35/45/52/58 antibodies among AS04-adjuvanted HPV16/18 vaccinated and non-vaccinated Ugandan girls aged 10–16 years

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    BACKGROUND: Data on Human Papilloma virus (HPV) vaccine immune response in sub-Saharan Africa is still sparse yet such knowledge is critical for optimal implementation and monitoring of HPV vaccines. Our primary objective was to evaluate levels of anti-HPV-16/18 antibodies and six other ‘high risk’ HPV (hrHPV) types among the vaccinated and unvaccinated Ugandan girls. METHODS: We conducted a cross sectional study among AS04-adjuvanted HPV-16/18 vaccinated and unvaccinated school girls aged 10–16 years in Western Uganda using purposive sampling. The vaccinated girls were at 18 months post vaccination. After consenting and assenting, data was collected using interviewer administered questionnaires for demographics and sexual history. Blood was drawn from which serum samples were analysed by the multiplex HPV serology technology to determine anti-HPV antibody levels to HPV-16/18 and six other hrHPV types (31, 33, 35, 45, 52 and 58). The antibody levels were expressed as Median Fluorescent Intensity (MFI). A total of 207 vaccinated [mean age 13.1 years (SD 1.5); range 10-16 years] and 197 unvaccinated girls [mean age 13.6 years (SD 1.3); range 10-16 years] participated in the study. Sexual activity was self reported among 14/207 (6.8%) vaccinated and 5/197 (2.5%) unvaccinated girls. The MFI levels for HPV-16 and HPV-18 were 15 and 20 times higher respectively in the vaccinated girls than in the unvaccinated girls. HPV-16 mean MFI level was 4691(SD 1812; 95% CI: 4438-4958) among the vaccinated compared to 218 (SD 685; 95% CI: 190-252) among the unvaccinated girls. For HPV-18 the mean MFI level was 1615 (SD 1326; 95% CI: 1470-1776) among the vaccinated compared to MFI 103 (SD 506; 95% CI: 88 -121) among unvaccinated girls. In addition antibody levels to non vaccine hrHPV types (31, 33, 35, 45, 52 and 58) were all significantly higher in the vaccinated group than in the unvaccinated group (p<0.01). CONCLUSION: The AS04-Adjuvanted HPV-16/18 vaccinated girls showed a higher level of antibodies to HPV-16/18 and other non-vaccine hrHPV types compared to the unvaccinated girls. This may translate into protection against HPV-16/18 and other hrHPV types

    Clinical Ethics in Gabon: The Spectrum of Clinical Ethical Issues Based on Findings from In-Depth Interviews at Three Public Hospitals

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    Introduction Unlike issues in biomedical research ethics, ethical challenges arising in daily clinical care in Sub-Saharan African countries have not yet been studied in a systematic manner. However this has to be seen as a distinct entity as we argue in this paper. Our aim was to give an overview of the spectrum of clinical ethical issues and to understand what influences clinical ethics in the Sub-Saharan country of Gabon. Materials and Methods In-depth interviews with 18 health care professionals were conducted at three hospital sites in Gabon. Interview transcripts were analyzed using a grounded theory approach (open and axial coding),giving a qualitative spectrum of categories for clinical ethical issues. Validity was checked at a meeting with study participants and other health care experts in Gabon after analysis of the data. Results Twelve main categories (with 28 further-specified subcategories) for clinical ethical issues were identified and grouped under three core categories: A) micro level: "confidentiality and information","interpersonal, relational and behavioral issues","psychological strain of individuals",and "scarce resources";B) meso level: "structural issues of medical institutions","issues with private clinics","challenges connected to the family",and "issues of education, training and competence";and C) macro level: "influence of society, culture, religion and superstition","applicability of western medicine","structural issues on the political level",and "legal issues". Discussion Interviewees reported a broad spectrum of clinical ethical issues that go beyond challenges related to scarce financial and human resources. Specific socio-cultural, historical and educational backgrounds also played an important role. In fact these influences are central to an understanding of clinical ethics in the studied local context. Further research in the region is necessary to put our study into perspective. As many participants reported a lack of awareness of ethical issues amongst other health care professionals in daily clinical practice, we suggest that international organizations and national medical schools should consider infrastructure and tools to improve context-sensitive capacity building in clinical ethics for Sub-Saharan African countries like Gabon

    Cheating the locals: invasive mussels steal and benefit from the cooling effect of indigenous mussels

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    The indigenous South African mussel Perna perna gapes during periods of aerial exposure to maintain aerobic respiration. This behaviour has no effect on the body temperatures of isolated individuals, but when surrounded by conspecifics, beneficial cooling effects of gaping emerge. It is uncertain, however, whether the presence of the invasive mussel Mytilus galloprovincialis limits the ability of P. perna for collective thermoregulation. We investigated whether varying densities of P. perna and M. galloprovincialis influences the thermal properties of both natural and artificial mussel beds during periods of emersion. Using infrared thermography, body temperatures of P. perna within mixed artificial beds were shown to increase faster and reach higher temperatures than individuals in conspecific beds, indicating that the presence of M. galloprovincialis limits the group cooling effects of gaping. In contrast, body temperatures of M. galloprovincialis within mixed artificial mussel beds increased slower and exhibited lower temperatures than for individuals in beds comprised entirely of M. galloprovincialis. Interestingly, differences in bed temperatures and heating rates were largely dependent on the size of mussels, with beds comprised of larger individuals experiencing less thermal stress irrespective of species composition. The small-scale patterns of thermal stress detected within manipulated beds were not observed within naturally occurring mixed mussel beds. We propose that small-scale differences in topography, size-structure, mussel bed size and the presence of organisms encrusting the mussel shells mask the effects of gaping behaviour within natural mussel beds. Nevertheless, the results from our manipulative experiment indicate that the invasive species M. galloprovincialis steals thermal properties as well as resources from the indigenous mussel P. perna. This may have significant implications for predicting how the co-existence of these two species may change as global temperatures continue to rise

    Changes in smoking prevalence among U.S. adults by state and region: Estimates from the Tobacco Use Supplement to the Current Population Survey, 1992-2007

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    <p>Abstract</p> <p>Background</p> <p>Tobacco control policies at the state level have been a critical impetus for reduction in smoking prevalence. We examine the association between recent changes in smoking prevalence and state-specific tobacco control policies and activities in the entire U.S.</p> <p>Methods</p> <p>We analyzed the 1992-93, 1998-99, and 2006-07 Tobacco Use Supplement to the Current Population Survey (TUS-CPS) by state and two indices of state tobacco control policies or activities [initial outcome index (IOI) and the strength of tobacco control (SOTC) index] measured in 1998-1999. The IOI reflects cigarette excise taxes and indoor air legislation, whereas the SOTC reflects tobacco control program resources and capacity. Pearson Correlation coefficient between the proportionate change in smoking prevalence from 1992-93 to 2006-07 and indices of tobacco control activities or programs was the main outcome measure.</p> <p>Results</p> <p>Smoking prevalence decreased from 1992-93 to 2006-07 in both men and women in all states except Wyoming, where no reduction was observed among men, and only a 6.9% relative reduction among women. The percentage reductions in smoking in men and women respectively were the largest in the West (average decrease of 28.5% and 33.3%) and the smallest in the Midwest (18.6% and 20.3%), although there were notable exceptions to this pattern. The decline in smoking prevalence by state was correlated with the state's IOI in both women and men (r = -0.49, p < 0.001; r = -0.31, p = 0.03; respectively) and with state's SOTC index in women(r = -0.30, p = 0.03 0), but not men (r = -0.21, p = 0.14).</p> <p>Conclusion</p> <p>State level policies on cigarette excise taxes and indoor air legislation correlate strongly with reductions in smoking prevalence since 1992. Strengthening and systematically implementing these policies could greatly accelerate further reductions in smoking.</p

    Acyl-Protein Thioesterase 2 Catalizes the Deacylation of Peripheral Membrane-Associated GAP-43

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    An acylation/deacylation cycle is necessary to maintain the steady-state subcellular distribution and biological activity of S-acylated peripheral proteins. Despite the progress that has been made in identifying and characterizing palmitoyltransferases (PATs), much less is known about the thioesterases involved in protein deacylation. In this work, we investigated the deacylation of growth-associated protein-43 (GAP-43), a dually acylated protein at cysteine residues 3 and 4. Using fluorescent fusion constructs, we measured in vivo the rate of deacylation of GAP-43 and its single acylated mutants in Chinese hamster ovary (CHO)-K1 and human HeLa cells. Biochemical and live cell imaging experiments demonstrated that single acylated mutants were completely deacylated with similar kinetic in both cell types. By RT-PCR we observed that acyl-protein thioesterase 1 (APT-1), the only bona fide thioesterase shown to mediate deacylation in vivo, is expressed in HeLa cells, but not in CHO-K1 cells. However, APT-1 overexpression neither increased the deacylation rate of single acylated GAP-43 nor affected the steady-state subcellular distribution of dually acylated GAP-43 both in CHO-K1 and HeLa cells, indicating that GAP-43 deacylation is not mediated by APT-1. Accordingly, we performed a bioinformatic search to identify putative candidates with acyl-protein thioesterase activity. Among several candidates, we found that APT-2 is expressed both in CHO-K1 and HeLa cells and its overexpression increased the deacylation rate of single acylated GAP-43 and affected the steady-state localization of diacylated GAP-43 and H-Ras. Thus, the results demonstrate that APT-2 is the protein thioesterase involved in the acylation/deacylation cycle operating in GAP-43 subcellular distribution
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