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Candidate polyanion microbicides inhibit HIV-1 infection and dissemination pathways in human cervical explants.
BACKGROUND: Heterosexual intercourse remains the major route of HIV-1 transmission worldwide, with almost 5 million new infections occurring each year. Women increasingly bear a disproportionate burden of the pandemic, thus there is an urgent need to develop new strategies to reduce HIV-1 transmission that could be controlled by women themselves. The potential of topical microbicides to reduce HIV transmission across mucosal surfaces has been clearly identified, and some agents are currently under evaluation in clinical trials. Many of these "first generation" microbicides consist of polyanionic compounds designed to interfere with viral attachment. Here we have evaluated two candidate polyanion compounds in clinical trials, PRO 2000 and dextrin sulphate (DxS) to determine their safety and efficacy against in vitro HIV-1 and HSV-2 infection using cellular and tissue explant models.
RESULTS: PRO 2000 and DxS potently inhibited infection by HIV-1 X4 and R5 isolates when present during viral exposure. However PRO 2000 required 10-fold and DxS 2000-fold more compound to block infection with R5 virus than X4. While both compounds were virucidal for X4 HIV-1, neither was virucidal for R5 virus. PRO 2000 efficiently inhibited infection of cervical explants and dissemination of virus by migratory DC. DxS was less active, able to completely inhibit cervical explant infection, but providing only partial reduction of virus dissemination by DC. PRO 2000, but not DxS, also inhibited HIV-1 binding to DC-SIGN+ cells and trans infection of co-cultured target cells. The inflammatory potential of both compounds was screened by measurement of cytokine production from cervical explants, and statistically significant increases were only observed for IL-1beta and RANTES following treatment with PRO 2000. Both compounds also demonstrated potent activity against HSV-2 infection of cervical epithelial cells.
CONCLUSION: Our results demonstrate that PRO 2000 is a potent inhibitor of R5 HIV-1 infection and dissemination pathways in human cervical explants. DxS, while demonstrating significant inhibition of R5 infection, was less active against DC mediated dissemination pathways. PRO 2000 has now entered human phase III efficacy trials
Molecular astronomy of cool stars and sub-stellar objects
The optical and infrared spectra of a wide variety of `cool' astronomical
objects including the Sun, sunspots, K-, M- and S-type stars, carbon stars,
brown dwarfs and extrasolar planets are reviewed. The review provides the
necessary astronomical background for chemical physicists to understand and
appreciate the unique molecular environments found in astronomy. The
calculation of molecular opacities needed to simulate the observed spectral
energy distributions is discussed
The role of microbes in rumen lipolysis and biohydrogenation and their manipulation
Despite the fact that the ruminant diet is rich in polyunsaturated fatty acids (PUFA), ruminant products - meat, milk and dairy - contain mainly saturated fatty acids (SFA) because of bacterial lipolysis and subsequent biohydrogenation of ingested PUFA in the rumen. The link between SFA consumption by man and coronary heart disease is well established. In contrast, ruminant products also contain fatty acids that are known to be beneficial to human health, namely conjugated linoleic acids (CLAs). The aims of research in this field have been to understand the microbial ecology of lipolysis and biohydrogenation and to find ways of manipulating ruminal microbes to increase the flow of PUFA and CLA from the rumen into meat and milk. This review describes our present understanding of the microbial ecology of ruminal lipid metabolism, including some apparently anomalous and paradoxical observations, and the status of how the metabolism may be manipulated and the possible consequential effects on other aspects of ruminal digestion. Intuitively, it may appear that inhibiting the ruminal lipase would cause more dietary PUFA to reach the mammary gland. However, lipolysis releases the non-esterified fatty acids that form the substrates for biohydrogenation, but which can, if they accumulate, inhibit the whole process. Thus, increasing lipase activity could be beneficial if the increased release of non-esterified PUFA inhibited the metabolism of CLA. Rumen ciliate protozoa do not carry out biohydrogenation, yet protozoal lipids are much more highly enriched in CLA than bacterial lipids. How could this happen if protozoa do not metabolise PUFA? The answer seems to lie in the ingestion of plant organelles, particularly chloroplasts, and the partial metabolism of the fatty acids by contaminating bacteria. Bacteria related to Butyrivibrio fibrisolvens are by far the most active and numerous biohydrogenating bacteria isolated from the rumen. But do we misunderstand the role of different bacterial species in biohydrogenation because there are uncultivated species that we need to understand and include in the analysis? Manipulation methods include dietary vegetable and fish oils and plant-derived chemicals. Their usefulness, efficacy and possible effects on fatty acid metabolism and on ruminal microorganisms and other areas of their metabolism are described, and areas of opportunity identified
“Free Will and Affirmation: Assessing Honderich’s Third Way”
In the third and final part of his A Theory of Determinism (TD) Ted Honderich addresses the fundamental question concerning “the consequences of determinism.” The critical question he aims to answer is what follows if determinism is true? This question is, of course, intimately bound up with the problem of free will and, in particular, with the question of whether or not the truth of determinism is compatible or incompatible with the sort of freedom required for moral responsibility. It is Honderich’s aim to provide a solution to “the problem of the consequences of determinism” and a key element of this is his articulation and defence of an alternative response to the implications of determinism that collapses the familiar Compatibilist/Incompatibilist dichotomy. Honderich offers us a third way – the response of “Affirmation” (HFY 125-6). Although his account of Affirmation has application and relevance to issues and features beyond freedom and responsibility, my primary concern in this essay will be to examine Honderich’s theory of “Affirmation” as it concerns the free will problem
Biohydrogenation of 22:6n-3 by Butyrivibrio proteoclasticus P18
Background: Rumen microbes metabolize 22:6n-3. However, pathways of 22:6n-3 biohydrogenation and ruminal microbes involved in this process are not known. In this study, we examine the ability of the well-known rumen biohydrogenating bacteria, Butyrivibrio fibrisolvens D1 and Butyrivibrio proteoclasticus P18, to hydrogenate 22:6n-3.
Results: Butyrivibrio fibrisolvens D1 failed to hydrogenate 22:6n-3 (0.5 to 32 mu g/mL) in growth medium containing autoclaved ruminal fluid that either had or had not been centrifuged. Growth of B. fibrisolvens was delayed at the higher 22:6n-3 concentrations; however, total volatile fatty acid production was not affected. Butyrivibrio proteoclasticus P18 hydrogenated 22:6n-3 in growth medium containing autoclaved ruminal fluid that either had or had not been centrifuged. Biohydrogenation only started when volatile fatty acid production or growth of B. proteoclasticus P18 had been initiated, which might suggest that growth or metabolic activity is a prerequisite for the metabolism of 22:6n-3. The amount of 22:6n-3 hydrogenated was quantitatively recovered in several intermediate products eluting on the gas chromatogram between 22:6n-3 and 22:0. Formation of neither 22:0 nor 22:6 conjugated fatty acids was observed during 22:6n-3 metabolism. Extensive metabolism was observed at lower initial concentrations of 22:6n-3 (5, 10 and 20 mu g/mL) whereas increasing concentrations of 22:6n-3 (40 and 80 mu g/mL) inhibited its metabolism. Stearic acid formation (18:0) from 18:2n-6 by B. proteoclasticus P18 was retarded, but not completely inhibited, in the presence of 22:6n-3 and this effect was dependent on 22:6n-3 concentration.
Conclusions: For the first time, our study identified ruminal bacteria with the ability to hydrogenate 22:6n-3. The gradual appearance of intermediates indicates that biohydrogenation of 22:6n-3 by B. proteoclasticus P18 occurs by pathways of isomerization and hydrogenation resulting in a variety of unsaturated 22 carbon fatty acids. During the simultaneous presence of 18:2n-6 and 22:6n-3, B. proteoclasticus P18 initiated 22:6n-3 metabolism before converting 18:1 isomers into 18:0
Serial Search Based Code Acquisition in the Cooperative MIMO Aided DS-CDMA Downlink
Full text of this paper is not available in UHRAFocal blockade of postsynaptic acetylcholine receptors (AChRs) in a small region of the neuromuscular junction may cause long-term synapse elimination at that site. Blockade of the whole junction does not cause synapse loss, indicating that it is the contrast in postsynaptic activity between the blocked and unblocked regions which causes withdrawal of the synaptic terminals. This phenomenon can be explained by the dual role of calcium, both in controlling AChR gene transcription and influencing AChR aggregation. A computational model is provided and the stability of the solutions is confirmed by theoretical analysis and computer simulation
Interaction of sexual dimorphism and gene dosage imbalance in skeletal deficits associated with Down syndrome
All individuals with Down syndrome (DS), which results from trisomy of human chromosome 21 (Ts21), present with skeletal abnormalities typified by craniofacial features, short stature and low bone mineral density (BMD). Differences in skeletal deficits between males and females with DS suggest a sexual dimorphism in how trisomy affects bone. Dp1Tyb mice contain three copies of all of the genes on mouse chromosome 16 that are homologous to human chromosome 21, males and females are fertile, and therefore are an excellent model to test the hypothesis that gene dosage influences the sexual dimorphism of bone abnormalities in DS. Dp1Tyb as compared to control littermate mice at time points associated with bone accrual (6 weeks) and skeletal maturity (16 weeks) showed deficits in BMD and trabecular architecture that occur largely through interactions between sex and genotype and resulted in lower percent bone volume in all female and Dp1Tyb male mice. Cortical bone in Dp1Tyb as compared to control mice exhibited different changes over time influenced by sex × genotype interactions including reduced cortical area in both male and female Dp1Tyb mice. Mechanical testing analyses suggested deficits in whole bone properties such as bone mass and geometry, but improved material properties in female and Dp1Tyb mice. Sexual dimorphisms and the influence of trisomic gene dosage differentially altered cellular properties of male and female Dp1Tyb bone. These data establish sex, gene dosage, skeletal site and age as important factors in skeletal development of DS model mice, paving the way for identification of the causal dosage-sensitive genes. Skeletal differences in developing male and female Dp1Tyb DS model mice replicated differences in less-studied adolescents with DS and established a foundation to understand the etiology of trisomic bone deficits
The post-ICU presentation screen (PICUPS) and rehabilitation prescription (RP) for intensive care survivors part I: Development and preliminary clinimetric evaluation
BANCKGROUND: Patients who have had prolonged stays in intensive care have ongoing rehabilitation needs. This is especially true of COVID-19 ICU patients, who can suffer diverse long-term ill effects. Currently there is no systematic data collection to guide the needs for therapy input for either of these groups nor to inform planning and development of rehabilitation services. These issues could be resolved in part by the systematic use of a clinical tool to support decision-making as patients progress from the Intensive Care Unit (ICU), through acute hospital care and onwards into rehabilitation. We describe (i) the development of such a tool (the Post-ICU Presentation Screen (PICUPS)) and (ii) the subsequent preparation of a person-centred Rehabilitation Prescription (RP) to travel with the patient as they continue down the care pathway. METHODS: PICUPS development was led by a core group of experienced clinicians representing the various disciplines involved in post-ICU rehabilitation. Key constructs and item-level descriptors were identified by group consensus. Piloting was performed as part of wider clinical engagement in 26 acute hospitals across England. Development and validation of such a tool requires clinimetric analysis, and this was based on classical test theory. Teams also provided feedback about the feasibility and utility of the tool. RESULTS: Initial PICUPS design yielded a 24-item tool. In piloting, a total of 552 records were collated from 314 patients, of which 121 (38.5%) had COVID-19. No obvious floor or ceiling effects were apparent. Exploratory factor analysis provided evidence of uni-dimensionality with strong loading on the first principal component accounting for 51% of the variance and Cronbach’s alpha for the full-scale score 0.95 – although a 3-factor solution accounted for a further 21%. The PICUPS was responsive to change both at full scale- and item-level. In general, positive responses were seen regarding the tool’s ability to describe the patients during their clinical course, engage and flag the relevant professionals needed, and to inform what should be included in an RP. CONCLUSIONS: The PICUPS tool has robust scaling properties as a clinical measure and is potentially useful as a tool for identifying rehabilitation needs as patients step down from ICU and acute hospital care
Re-engage: A novel nurse-led program for survivors of childhood cancer who are disengaged from cancer-related care
Background: Survivors of childhood cancer often experience treatmentrelated chronic health conditions. Survivorship care improves survivors' physical and mental health, yet many are disengaged from care. Innovative models of care are necessary to overcome patient-reported barriers to accessing survivorship care and to maximize survivors' health. Methods:We piloted a novel survivorship program, called "Reengage,"a distance-delivered, nurse-led intervention aiming to engage, educate, and empower survivors not receiving any cancerrelated care. Re-engage involves a nurse-led consultation delivered via telephone/online to establish survivors' medical history and needs. Participants completed questionnaires at baseline, 1 month postintervention, and 6-month follow-up. Results: A total of 27 survivors who had not accessed survivorship care in the last 2 years participated (median age, 31 years; interquartile range [IQR], 27-39 years); of which, 82% were at high-risk for treatment-related complications. Participation in Re-engage was high (75%) and there was no attrition once survivors enrolled. At 1 month postintervention, 92% of survivors reported that Re-engage was "beneficial,"which all survivors reported at 6-month follow-up. Survivors' overall satisfaction with their care increased from 52% before Re-engage to 84% at 1 month postintervention. Survivors' mean self-efficacy scores remained similar from baseline to 1 month postintervention (b520.33, 95% CI, 21.31 to 0.65), but increased significantly from baseline to 6-month follow-up (b 5 1.64, 95% CI, 0.28-3.00). At 6-month follow-up, 73% of survivors showed an increase in health-related self-efficacy compared with baseline. Conclusions: Re-engage is a highly acceptable and feasible intervention and promotes health-related self-efficacy, which is integral to survivors being advocates for their own health. Further empirical work is needed to evaluate the long-term efficacy of Re-engage. Trial registration: ACTRN12618000194268
Fission yeast 26S proteasome mutants are multi-drug resistant due to stabilization of the pap1 transcription factor
Here we report the result of a genetic screen for mutants resistant to the microtubule poison methyl benzimidazol-2-yl carbamate (MBC) that were also temperature sensitive for growth. In total the isolated mutants were distributed in ten complementation groups. Cloning experiments revealed that most of the mutants were in essential genes encoding various 26S proteasome subunits. We found that the proteasome mutants are multi-drug resistant due to stabilization of the stress-activated transcription factor Pap1. We show that the ubiquitylation and ultimately the degradation of Pap1 depend on the Rhp6/Ubc2 E2 ubiquitin conjugating enzyme and the Ubr1 E3 ubiquitin-protein ligase. Accordingly, mutants lacking Rhp6 or Ubr1 display drug-resistant phenotypes
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