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Talley EM, Lei Q, Sirois JE, Bayliss DA. TASK-1, a two-pore domain K+ channel, is modulated by multiple neurotransmitters in motoneurons. Neuron 2000; 25:399-410. [PMID: 10719894 DOI: 10.1016/s0896-6273(00)80903-4] [Citation(s) in RCA: 349] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Inhibition of "leak" potassium (K+) channels is a widespread CNS mechanism by which transmitters induce slow excitation. We show that TASK-1, a two pore domain K+ channel, provides a prominent leak K+ current and target for neurotransmitter modulation in hypoglossal motoneurons (HMs). TASK-1 mRNA is present at high levels in motoneurons, including HMs, which express a K+ current with pH- and voltage-dependent properties virtually identical to those of the cloned channel. This pH-sensitive K+ channel was fully inhibited by serotonin, norepinephrine, substance P, thyrotropin-releasing hormone, and 3,5-dihydroxyphenylglycine, a group I metabotropic glutamate receptor agonist. The neurotransmitter effect was entirely reconstituted in HEK 293 cells coexpressing TASK-1 and the TRH-R1 receptor. Given its expression patterns and the widespread prevalence of this neuromodulatory mechanism, TASK-1 also likely supports this action in other CNS neurons.
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Gaolathe T, Wirth KE, Holme MP, Makhema J, Moyo S, Chakalisa U, Yankinda EK, Lei Q, Mmalane M, Novitsky V, Okui L, van Widenfelt E, Powis KM, Khan N, Bennett K, Bussmann H, Dryden-Peterson S, Lebelonyane R, El-Halabi S, Mills LA, Marukutira T, Wang R, Tchetgen EJT, DeGruttola V, Essex M, Lockman S. Botswana's progress toward achieving the 2020 UNAIDS 90-90-90 antiretroviral therapy and virological suppression goals: a population-based survey. Lancet HIV 2016; 3:e221-30. [PMID: 27126489 PMCID: PMC5146754 DOI: 10.1016/s2352-3018(16)00037-0] [Citation(s) in RCA: 184] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Revised: 02/24/2016] [Accepted: 03/01/2016] [Indexed: 01/09/2023]
Abstract
BACKGROUND HIV programmes face challenges achieving high rates of HIV testing and treatment needed to optimise health and to reduce transmission. We used data from the Botswana Combination Prevention Project study survey to assess Botswana's progress toward achieving UNAIDS targets for 2020: 90% of all people living with HIV knowing their status, 90% of these receiving sustained antiretroviral therapy (ART), and 90% of those having virological suppression (90-90-90). METHODS A population-based sample of individuals was recruited and interviewed in 30 rural and periurban communities from Oct 30, 2013, to Nov 24, 2015, as part of a large, ongoing community-randomised trial designed to assess the effect of a combination prevention package on HIV incidence. A random sample of about 20% of households in each community was selected. Consenting household residents aged 16-64 years who were Botswana citizens or spouses of citizens responded to a questionnaire and had blood drawn for HIV testing in the absence of documentation of positive HIV status. Viral load testing was done in all HIV-infected participants, irrespective of treatment status. We used modified Poisson generalised estimating equations to obtain prevalence ratios, corresponding Huber robust SEs, and 95% Wald CIs to examine associations between individual sociodemographic factors and a binary outcome indicating achievement of the three individual and combined overall 90-90-90 targets. The study is registered at ClinicalTrials.gov, number NCT01965470. FINDINGS 81% of enumerated eligible household members took part in the survey (10% refused and 9% were absent). Among 12 610 participants surveyed, 3596 (29%) were infected with HIV, and 2995 (83·3%, 95% CI 81·4-85·2) of these individuals already knew their HIV status. Among those who knew their HIV status, 2617 (87·4%, 95% CI 85·8-89·0) were receiving ART (95% of those eligible by national guidelines, and 73% of all infected people). Of the 2609 individuals receiving ART with a viral load measurement, 2517 (96·5%, 95% CI 96·0-97·0) had viral load of 400 copies per mL or less. Overall, 70·2% (95% CI 67·5-73·0) of HIV-infected people had virological suppression, close to the UNAIDS target of 73%. INTERPRETATION UNAIDS 90-90-90 targets are achievable even in resource-constrained settings with high HIV burden. FUNDING US President's Emergency Plan for AIDS Relief through the Centers for Disease Control and Prevention.
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Makhema J, Wirth KE, Pretorius Holme M, Gaolathe T, Mmalane M, Kadima E, Chakalisa U, Bennett K, Leidner J, Manyake K, Mbikiwa AM, Simon SV, Letlhogile R, Mukokomani K, van Widenfelt E, Moyo S, Lebelonyane R, Alwano MG, Powis KM, Dryden-Peterson SL, Kgathi C, Novitsky V, Moore J, Bachanas P, Abrams W, Block L, El-Halabi S, Marukutira T, Mills LA, Sexton C, Raizes E, Gaseitsiwe S, Bussmann H, Okui L, John O, Shapiro RL, Pals S, Michael H, Roland M, DeGruttola V, Lei Q, Wang R, Tchetgen Tchetgen E, Essex M, Lockman S. Universal Testing, Expanded Treatment, and Incidence of HIV Infection in Botswana. N Engl J Med 2019; 381:230-242. [PMID: 31314967 PMCID: PMC6800102 DOI: 10.1056/nejmoa1812281] [Citation(s) in RCA: 168] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
BACKGROUND The feasibility of reducing the population-level incidence of human immunodeficiency virus (HIV) infection by increasing community coverage of antiretroviral therapy (ART) and male circumcision is unknown. METHODS We conducted a pair-matched, community-randomized trial in 30 rural or periurban communities in Botswana from 2013 to 2018. Participants in 15 villages in the intervention group received HIV testing and counseling, linkage to care, ART (started at a higher CD4 count than in standard care), and increased access to male circumcision services. The standard-care group also consisted of 15 villages. Universal ART became available in both groups in mid-2016. We enrolled a random sample of participants from approximately 20% of households in each community and measured the incidence of HIV infection through testing performed approximately once per year. The prespecified primary analysis was a permutation test of HIV incidence ratios. Pair-stratified Cox models were used to calculate 95% confidence intervals. RESULTS Of 12,610 enrollees (81% of eligible household members), 29% were HIV-positive. Of the 8974 HIV-negative persons (4487 per group), 95% were retested for HIV infection over a median of 29 months. A total of 57 participants in the intervention group and 90 participants in the standard-care group acquired HIV infection (annualized HIV incidence, 0.59% and 0.92%, respectively). The unadjusted HIV incidence ratio in the intervention group as compared with the standard-care group was 0.69 (P = 0.09) by permutation test (95% confidence interval [CI], 0.46 to 0.90 by pair-stratified Cox model). An end-of-trial survey in six communities (three per group) showed a significantly greater increase in the percentage of HIV-positive participants with an HIV-1 RNA level of 400 copies per milliliter or less in the intervention group (18 percentage points, from 70% to 88%) than in the standard-care group (8 percentage points, from 75% to 83%) (relative risk, 1.12; 95% CI, 1.09 to 1.16). The percentage of men who underwent circumcision increased by 10 percentage points in the intervention group and 2 percentage points in the standard-care group (relative risk, 1.26; 95% CI, 1.17 to 1.35). CONCLUSIONS Expanded HIV testing, linkage to care, and ART coverage were associated with increased population viral suppression. (Funded by the President's Emergency Plan for AIDS Relief and others; Ya Tsie ClinicalTrials.gov number, NCT01965470.).
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Bayliss DA, Talley EM, Sirois JE, Lei Q. TASK-1 is a highly modulated pH-sensitive 'leak' K(+) channel expressed in brainstem respiratory neurons. RESPIRATION PHYSIOLOGY 2001; 129:159-74. [PMID: 11738652 DOI: 10.1016/s0034-5687(01)00288-2] [Citation(s) in RCA: 133] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Central respiratory chemoreceptors adjust respiratory drive in a homeostatic response to alterations in brain pH and/or P(CO(2)). Multiple brainstem sites are proposed as neural substrates for central chemoreception, but molecular substrates that underlie chemosensitivity in respiratory neurons have not been identified. In rat brainstem neurons expressing transcripts for TASK-1, a two-pore domain K(+) channel, we characterized K(+) currents with kinetic and voltage-dependent properties identical to cloned rat TASK-1 currents. Native currents were sensitive to acid and alkaline shifts in the same physiological pH range as TASK-1 (pK approximately 7.4), and native and cloned pH-sensitive currents were modulated similarly by neurotransmitters and inhalational anesthetics. This pH-sensitive TASK-1 channel is an attractive candidate to mediate chemoreception because it is functionally expressed in respiratory-related neurons, including airway motoneurons and putative chemoreceptor neurons of locus coeruleus (LC). Inhibition of TASK-1 channels by extracellular acidosis can depolarize and increase excitability in those cells, thereby contributing to chemoreceptor function in LC neurons and directly enhancing respiratory motoneuronal output.
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Review |
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Ke X, Lei Q, James SJ, Kelleher SL, Melnyk S, Jernigan S, Yu X, Wang L, Callaway CW, Gill G, Chan GM, Albertine KH, McKnight RA, Lane RH. Uteroplacental insufficiency affects epigenetic determinants of chromatin structure in brains of neonatal and juvenile IUGR rats. Physiol Genomics 2005; 25:16-28. [PMID: 16380407 DOI: 10.1152/physiolgenomics.00093.2005] [Citation(s) in RCA: 117] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Intrauterine growth retardation (IUGR) increases the risk of neuroendocrine reprogramming. In the rat, IUGR leads to persistent changes in cerebral mRNA levels. This suggests lasting alterations in IUGR cerebral transcriptional regulation, which may result from changes in chromatin structure. Candidate nutritional triggers for these changes include altered cerebral zinc and one-carbon metabolite levels. We hypothesized that IUGR affects cerebral chromatin structure in neonatal and postnatal rat brains. Rats were rendered IUGR by bilateral uterine artery ligation; controls (Con) underwent sham surgery. At day of life 0 (d0), we measured cerebral DNA methylation, histone acetylation, expression of chromatin-affecting enzymes, and cerebral levels of one-carbon metabolites and zinc. At day of life 21 (d21), we measured cerebral DNA methylation and histone acetylation, as well as the caloric content of Con and IUGR rat breast milk. At d0, IUGR significantly decreased genome-wide and CpG island methylation, as well as increased histone 3 lysine 9 (H3/K9) and histone 3 lysine 14 (H3/K14) acetylation in the hippocampus and periventricular white matter, respectively. IUGR also decreased expression of the chromatin-affecting enzymes DNA methyltransferase 1 (DNMT1), methyl-CpG binding protein 2 (MeCP2), and histone deacetylase (HDAC)1 in association with increased cerebral levels of zinc. In d21 female IUGR rats, cerebral CpG DNA methylation remained lower, whereas H3/K9 and H3/K14 hyperacetylation persisted in hippocampus and white matter, respectively. In d21 male rats, IUGR decreased acetylation of H3/K9 and H3/K14 in these respective regions compared with controls. Despite these differences, caloric, fat, and protein content were similar in breast milk from Con and IUGR dams. We conclude that IUGR results in postnatal changes in cerebral chromatin structure and that these changes are sex specific.
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Research Support, Non-U.S. Gov't |
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117 |
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Lei Q, Talley EM, Bayliss DA. Receptor-mediated inhibition of G protein-coupled inwardly rectifying potassium channels involves G(alpha)q family subunits, phospholipase C, and a readily diffusible messenger. J Biol Chem 2001; 276:16720-30. [PMID: 11279027 DOI: 10.1074/jbc.m100207200] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
G protein-coupled inwardly rectifying K+ (GIRK) channels can be activated or inhibited by distinct classes of receptor (G(alpha)i/o- and G(alpha)q-coupled), providing dynamic regulation of cellular excitability. Receptor-mediated activation involves direct effects of G(beta)gamma subunits on GIRK channels, but mechanisms involved in GIRK channel inhibition have not been fully elucidated. An HEK293 cell line that stably expresses GIRK1/4 channels was used to test G protein mechanisms that mediate GIRK channel inhibition. In cells transiently or stably cotransfected with 5-HT1A (G(alpha)i/o-coupled) and TRH-R1 (G(alpha)q-coupled) receptors, 5-HT (5-hydroxytryptamine; serotonin) enhanced GIRK channel currents, whereas thyrotropin-releasing hormone (TRH) inhibited both basal and 5-HT-activated GIRK channel currents. Inhibition of GIRK channel currents by TRH primarily involved signaling by G(alpha)q family subunits, rather than G(beta)gamma dimers: GIRK channel current inhibition was diminished by Pasteurella multocida toxin, mimicked by constitutively active members of the G(alpha)q family, and reduced by minigene constructs that disrupt G(alpha)q signaling, but was completely preserved in cells expressing constructs that interfere with signaling by G(beta)gamma subunits. Inhibition of GIRK channel currents by TRH and constitutively active G(alpha)q was reduced by, an inhibitor of phospholipase C (PLC). Moreover, TRH- R1-mediated GIRK channel inhibition was diminished by minigene constructs that reduce membrane levels of the PLC substrate phosphatidylinositol bisphosphate, further implicating PLC. However, we found no evidence for involvement of protein kinase C, inositol trisphosphate, or intracellular calcium. Although these downstream signaling intermediaries did not contribute to receptor-mediated GIRK channel inhibition, bath application of TRH decreased GIRK channel activity in cell-attached patches. Together, these data indicate that receptor-mediated inhibition of GIRK channels involves PLC activation by G(alpha) subunits of the G(alpha)q family and suggest that inhibition may be communicated at a distance to GIRK channels via unbinding and diffusion of phosphatidylinositol bisphosphate away from the channel.
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MESH Headings
- Bacterial Proteins
- Bacterial Toxins/pharmacology
- Cell Line
- Cell Membrane/physiology
- Dimerization
- Enzyme Inhibitors/pharmacology
- Estrenes/pharmacology
- G Protein-Coupled Inwardly-Rectifying Potassium Channels
- GTP-Binding Protein alpha Subunits, Gq-G11
- Heterotrimeric GTP-Binding Proteins/chemistry
- Heterotrimeric GTP-Binding Proteins/physiology
- Humans
- Indoles/pharmacology
- Inositol 1,4,5-Trisphosphate/metabolism
- Maleimides/pharmacology
- Membrane Potentials/drug effects
- Pasteurella multocida
- Phorbol Esters/pharmacology
- Potassium Channel Blockers
- Potassium Channels/physiology
- Potassium Channels, Inwardly Rectifying
- Protein Subunits
- Pyrrolidinones/pharmacology
- Receptors, Serotonin/drug effects
- Receptors, Serotonin/physiology
- Receptors, Serotonin, 5-HT1
- Receptors, Thyrotropin-Releasing Hormone/drug effects
- Receptors, Thyrotropin-Releasing Hormone/physiology
- Recombinant Proteins/metabolism
- Serotonin/pharmacology
- Thyrotropin-Releasing Hormone/pharmacology
- Transfection
- Type C Phospholipases/metabolism
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Rotnitzky A, Lei Q, Sued M, Robins JM. Improved double-robust estimation in missing data and causal inference models. Biometrika 2012; 99:439-456. [PMID: 23843666 DOI: 10.1093/biomet/ass013] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Recently proposed double-robust estimators for a population mean from incomplete data and for a finite number of counterfactual means can have much higher efficiency than the usual double-robust estimators under misspecification of the outcome model. In this paper, we derive a new class of double-robust estimators for the parameters of regression models with incomplete cross-sectional or longitudinal data, and of marginal structural mean models for cross-sectional data with similar efficiency properties. Unlike the recent proposals, our estimators solve outcome regression estimating equations. In a simulation study, the new estimator shows improvements in variance relative to the standard double-robust estimator that are in agreement with those suggested by asymptotic theory.
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Journal Article |
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Lei Q, Jones MB, Talley EM, Schrier AD, McIntire WE, Garrison JC, Bayliss DA. Activation and inhibition of G protein-coupled inwardly rectifying potassium (Kir3) channels by G protein beta gamma subunits. Proc Natl Acad Sci U S A 2000; 97:9771-6. [PMID: 10944236 PMCID: PMC16940 DOI: 10.1073/pnas.97.17.9771] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
G protein-coupled inwardly rectifying potassium (GIRK) channels can be activated or inhibited by different classes of receptors, suggesting a role for G proteins in determining signaling specificity. Because G protein betagamma subunits containing either beta1 or beta2 with multiple Ggamma subunits activate GIRK channels, we hypothesized that specificity might be imparted by beta3, beta4, or beta5 subunits. We used a transfection assay in cell lines expressing GIRK channels to examine effects of dimers containing these Gbeta subunits. Inwardly rectifying K(+) currents were increased in cells expressing beta3 or beta4, with either gamma2 or gamma11. Purified, recombinant beta3gamma2 and beta4gamma2 bound directly to glutathione-S-transferase fusion proteins containing N- or C-terminal cytoplasmic domains of GIRK1 and GIRK4, indicating that beta3 and beta4, like beta1, form dimers that bind to and activate GIRK channels. By contrast, beta5-containing dimers inhibited GIRK channel currents. This inhibitory effect was obtained with either beta5gamma2 or beta5gamma11, was observed with either GIRK1,4 or GIRK1,2 channels, and was evident in the context of either basal or agonist-induced currents, both of which were mediated by endogenous Gbetagamma subunits. In cotransfection assays, beta5gamma2 suppressed beta1gamma2-activated GIRK currents in a dose-dependent manner consistent with competitive inhibition. Moreover, we found that beta5gamma2 could bind to the same GIRK channel cytoplasmic domains as other, activating Gbetagamma subunits. Thus, beta5-containing dimers inhibit Gbetagamma-stimulated GIRK channels, perhaps by directly binding to the channels. This suggests that beta5-containing dimers could act as competitive antagonists of other Gbetagamma dimers on GIRK channels.
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research-article |
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Novitsky V, Moyo S, Lei Q, DeGruttola V, Essex M. Impact of sampling density on the extent of HIV clustering. AIDS Res Hum Retroviruses 2014; 30:1226-35. [PMID: 25275430 PMCID: PMC4250956 DOI: 10.1089/aid.2014.0173] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Identifying and monitoring HIV clusters could be useful in tracking the leading edge of HIV transmission in epidemics. Currently, greater specificity in the definition of HIV clusters is needed to reduce confusion in the interpretation of HIV clustering results. We address sampling density as one of the key aspects of HIV cluster analysis. The proportion of viral sequences in clusters was estimated at sampling densities from 1.0% to 70%. A set of 1,248 HIV-1C env gp120 V1C5 sequences from a single community in Botswana was utilized in simulation studies. Matching numbers of HIV-1C V1C5 sequences from the LANL HIV Database were used as comparators. HIV clusters were identified by phylogenetic inference under bootstrapped maximum likelihood and pairwise distance cut-offs. Sampling density below 10% was associated with stochastic HIV clustering with broad confidence intervals. HIV clustering increased linearly at sampling density >10%, and was accompanied by narrowing confidence intervals. Patterns of HIV clustering were similar at bootstrap thresholds 0.7 to 1.0, but the extent of HIV clustering decreased with higher bootstrap thresholds. The origin of sampling (local concentrated vs. scattered global) had a substantial impact on HIV clustering at sampling densities ≥10%. Pairwise distances at 10% were estimated as a threshold for cluster analysis of HIV-1 V1C5 sequences. The node bootstrap support distribution provided additional evidence for 10% sampling density as the threshold for HIV cluster analysis. The detectability of HIV clusters is substantially affected by sampling density. A minimal genotyping density of 10% and sampling density of 50-70% are suggested for HIV-1 V1C5 cluster analysis.
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Research Support, N.I.H., Extramural |
11 |
56 |
10
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Zhang L, Li Y, Yang X, Wei J, Zhou S, Zhao Z, Cheng J, Duan H, Jia T, Lei Q, Huang J, Feng C. Characterization of Th17 and FoxP3(+) Treg Cells in Paediatric Psoriasis Patients. Scand J Immunol 2016; 83:174-80. [PMID: 26679087 DOI: 10.1111/sji.12404] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 12/03/2015] [Indexed: 12/01/2022]
Abstract
Psoriasis is one of the most common inflammatory skin conditions affecting both children and adults. Growing evidence indicates that T-helper 17 (Th17) cells and CD4(+) CD25(+) regulatory T (Treg) cells play an important role in the pathogenesis of psoriasis. However, the relationship between Th17 and Treg cells and their dynamic variations in paediatric psoriasis remain unclear. In this study, we found that both Th17 and FoxP3(+) Treg cells and the ratio of Th17 to Treg cell frequency in the peripheral circulation were increased in patients with paediatric psoriasis and were positively correlated with the disease severity. The function of Treg to suppress CD4(+) CD25(-) T cell proliferation and IFN-γ secretion was impaired during the onset of psoriasis. After disease remission, both the Th17 and Treg cell frequencies were decreased, and the suppressive function of the Treg cells was obviously restored. However, neither Treg cells from the disease onset nor those after remission can regulate IL-17 secretion by CD4(+) T cells. These findings will further our understanding of the associations between Th17 and Treg cells in paediatric psoriasis and their influence on disease severity.
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Research Support, Non-U.S. Gov't |
9 |
54 |
11
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Wang R, DeGruttola V, Lei Q, Mayer KH, Redline S, Hazra A, Mora S, Willett WC, Ganmaa D, Manson JE. The vitamin D for COVID-19 (VIVID) trial: A pragmatic cluster-randomized design. Contemp Clin Trials 2021; 100:106176. [PMID: 33045402 PMCID: PMC7547023 DOI: 10.1016/j.cct.2020.106176] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 10/03/2020] [Accepted: 10/06/2020] [Indexed: 12/27/2022]
Abstract
OBJECTIVES To determine the effect of vitamin D supplementation on disease progression and post-exposure prophylaxis for COVID-19 infection. We hypothesize that high-dose vitamin D3 supplementation will reduce risk of hospitalization/death among those with recently diagnosed COVID-19 infection and will reduce risk of COVID-19 infection among their close household contacts. METHODS We report the rationale and design of a planned pragmatic, cluster randomized, double-blinded trial (N = 2700 in total nationwide), with 1500 newly diagnosed individuals with COVID-19 infection, together with up to one close household contact each (~1200 contacts), randomized to either vitamin D3 (loading dose, then 3200 IU/day) or placebo in a 1:1 ratio and a household cluster design. The study duration is 4 weeks. The primary outcome for newly diagnosed individuals is the occurrence of hospitalization and/or mortality. Key secondary outcomes include symptom severity scores among cases and changes in the infection (seroconversion) status for their close household contacts. Changes in vitamin D 25(OH)D levels will be assessed and their relation to study outcomes will be explored. CONCLUSIONS The proposed pragmatic trial will allow parallel testing of vitamin D3 supplementation for early treatment and post-exposure prophylaxis of COVID-19. The household cluster design provides a cost-efficient approach to testing an intervention for reducing rates of hospitalization and/or mortality in newly diagnosed cases and preventing infection among their close household contacts.
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Clinical Trial Protocol |
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48 |
12
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Castles F, Isakov D, Lui A, Lei Q, Dancer CEJ, Wang Y, Janurudin JM, Speller SC, Grovenor CRM, Grant PS. Microwave dielectric characterisation of 3D-printed BaTiO3/ABS polymer composites. Sci Rep 2016; 6:22714. [PMID: 26940381 PMCID: PMC4778131 DOI: 10.1038/srep22714] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 02/22/2016] [Indexed: 11/17/2022] Open
Abstract
3D printing is used extensively in product prototyping and continues to emerge as a viable option for the direct manufacture of final parts. It is known that dielectric materials with relatively high real permittivity—which are required in important technology sectors such as electronics and communications—may be 3D printed using a variety of techniques. Among these, the fused deposition of polymer composites is particularly straightforward but the range of dielectric permittivities available through commercial feedstock materials is limited. Here we report on the fabrication of a series of composites composed of various loadings of BaTiO3 microparticles in the polymer acrylonitrile butadiene styrene (ABS), which may be used with a commercial desktop 3D printer to produce printed parts containing user-defined regions with high permittivity. The microwave dielectric properties of printed parts with BaTiO3 loadings up to 70 wt% were characterised using a 15 GHz split post dielectric resonator and had real relative permittivities in the range 2.6–8.7 and loss tangents in the range 0.005–0.027. Permittivities were reproducible over the entire process, and matched those of bulk unprinted materials, to within ~1%, suggesting that the technique may be employed as a viable manufacturing process for dielectric composites.
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Research Support, Non-U.S. Gov't |
9 |
44 |
13
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Boatright WL, Lei Q. Compounds Contributing to the “Beany” Odor of Aqueous Solutions of Soy Protein Isolates. J Food Sci 2006. [DOI: 10.1111/j.1365-2621.1999.tb15107.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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33 |
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Blake BL, Wing MR, Zhou JY, Lei Q, Hillmann JR, Behe CI, Morris RA, Harden TK, Bayliss DA, Miller RJ, Siderovski DP. G beta association and effector interaction selectivities of the divergent G gamma subunit G gamma(13). J Biol Chem 2001; 276:49267-74. [PMID: 11675383 DOI: 10.1074/jbc.m106565200] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
G gamma(13) is a divergent member of the G gamma subunit family considered to be a component of the gustducin G-protein heterotrimer involved in bitter and sweet taste reception in taste bud cells. G gamma(13) contains a C-terminal asparagine-proline-tryptophan (NPW) tripeptide, a hallmark of RGS protein G gamma-like (GGL) domains which dimerize exclusively with G beta(5) subunits. In this study, we investigated the functional range of G gamma(13) assembly with G beta subunits using multiple assays of G beta association and G beta gamma effector modulation. G gamma(13) was observed to associate with all five G beta subunits (G beta(1-5)) upon co-translation in vitro, as well as function with all five G beta subunits in the modulation of Kir3.1/3.4 (GIRK1/4) potassium and N-type (alpha(1B)) calcium channels. Multiple G beta/G gamma(13) pairings were also functional in cellular assays of phospholipase C (PLC) beta 2 activation and inhibition of G alpha(q)-stimulated PLC beta 1 activity. However, upon cellular co-expression of G gamma(13) with different G beta subunits, only G beta(1)/G gamma(13), G beta(3)/G gamma(13), and G beta(4)/G gamma(13) pairings were found to form stable dimers detectable by co-immunoprecipitation under high-detergent cell lysis conditions. Collectively, these data indicate that G gamma(13) forms functional G beta gamma dimers with a range of G beta subunits. Coupled with our detection of G gamma(13) mRNA in mouse and human brain and retina, these results imply that this divergent G gamma subunit can act in signal transduction pathways other than that dedicated to taste reception in sensory lingual tissue.
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Sloutskin E, Sapir Z, Bain CD, Lei Q, Wilkinson KM, Tamam L, Deutsch M, Ocko BM. Wetting, mixing, and phase transitions in Langmuir-Gibbs films. PHYSICAL REVIEW LETTERS 2007; 99:136102. [PMID: 17930612 DOI: 10.1103/physrevlett.99.136102] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2007] [Indexed: 05/25/2023]
Abstract
Millimolar bulk concentrations of the surfactant cetyltrimethylammonium bromide (CTAB) induce spreading of alkanes, H(CH(2))(n)H (denoted C(n)) 12< or =n< or =21, on the water surface, which is not otherwise wet by these alkanes. The novel Langmuir-Gibbs film (LGF) formed is a liquidlike monolayer comprising both alkanes and CTAB tails. Upon cooling, an ordering transition occurs, yielding a hexagonally packed, quasi-2D crystal. For 11< or =n< or =17 this surface-frozen LGF is a crystalline monolayer. For 18< or =n< or =21 the LGF is a bilayer with a crystalline, pure-alkane, upper monolayer, and a liquidlike lower monolayer. The phase diagram and film structure were determined by x-ray, ellipsometry, and surface tension measurements. A thermodynamic theory accounts quantitatively for the observations.
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Abstract
Outdoor air ventilation rates vary considerably between and within buildings, and may be too low in some spaces. The purpose of this study was to evaluate the potential work performance benefits of increased ventilation. We analyzed the literature relating work performance with ventilation rate and employed statistical analyses with weighting factors to combine the results of different studies. The studies included in the review assessed performance of various tasks in laboratory experiments and measured performance at work in real buildings. Almost all studies found increases in performance with higher ventilation rates. The studies indicated typically a 1-3% improvement in average performance per 10 l/s-person increase in outdoor air ventilation rate. The performance increase per unit increase in ventilation was bigger with ventilation rates below 20 l/s-person and almost negligible with ventilation rates over 45 l/s-person. The performance increase was statistically significant with increased ventilation rates up to 15 l/s-person with 95% CI and up to 17 l/s-person with 90% CI. Practical Implications We have demonstrated a quantitative relationship between work performance and ventilation within a wide range of ventilation rates. The model shows a continuous increase in performance per unit increase in ventilation rate from 6.5 l/s-person to 65 l/s-person. The increase is statistically significant up to 15 l/s-person. This relationship has a high level of uncertainty; however, use of this relationship in ventilation design and feasibility studies may be preferable to the current practice, which ignores the relationship between ventilation and productivity.
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Boatright W, Lei Q. Headspace Evaluation of Methanethiol and Dimethyl Trisulfide in Aqueous Solutions of Soy-protein Isolates. J Food Sci 2000. [DOI: 10.1111/j.1365-2621.2000.tb13593.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Novitsky V, Bussmann H, Logan A, Moyo S, van Widenfelt E, Okui L, Mmalane M, Baca J, Buck L, Phillips E, Tim D, McLane MF, Lei Q, Wang R, Makhema J, Lockman S, DeGruttola V, Essex M. Phylogenetic relatedness of circulating HIV-1C variants in Mochudi, Botswana. PLoS One 2013; 8:e80589. [PMID: 24349005 PMCID: PMC3859477 DOI: 10.1371/journal.pone.0080589] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Accepted: 10/04/2013] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Determining patterns of HIV transmission is increasingly important for the most efficient use of modern prevention interventions. HIV phylogeny can provide a better understanding of the mechanisms underlying HIV transmission networks in communities. METHODS To reconstruct the structure and dynamics of a local HIV/AIDS epidemic, the phylogenetic relatedness of HIV-1 subtype C env sequences obtained from 785 HIV-infected community residents in the northeastern sector of Mochudi, Botswana, during 2010-2013 was estimated. The genotyping coverage was estimated at 44%. Clusters were defined based on relatedness of HIV-1C env sequences and bootstrap support of splits. RESULTS The overall proportion of clustered HIV-1C env sequences was 19.1% (95% CI 17.5% to 20.8%). The proportion of clustered sequences from Mochudi was significantly higher than the proportion of non-Mochudi sequences that clustered, 27.0% vs. 14.7% (p = 5.8E-12; Fisher exact test). The majority of clustered Mochudi sequences (90.1%; 95% CI 85.1% to 93.6%) were found in the Mochudi-unique clusters. None of the sequences from Mochudi clustered with any of the 1,244 non-Botswana HIV-1C sequences. At least 83 distinct HIV-1C variants, or chains of HIV transmission, in Mochudi were enumerated, and their sequence signatures were reconstructed. Seven of 20 genotyped seroconverters were found in 7 distinct clusters. CONCLUSIONS The study provides essential characteristics of the HIV transmission network in a community in Botswana, suggests the importance of high sampling coverage, and highlights the need for broad HIV genotyping to determine the spread of community-unique and community-mixed viral variants circulating in local epidemics. The proposed methodology of cluster analysis enumerates circulating HIV variants and can work well for surveillance of HIV transmission networks. HIV genotyping at the community level can help to optimize and balance HIV prevention strategies in trials and combined intervention packages.
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Dibenedetto LM, Lei Q, Gilroy AM, Hermey DC, Marks SC, Page DW. Variations in the inferior pelvic pathway of the lateral femoral cutaneous nerve: implications for laparoscopic hernia repair. Clin Anat 1996; 9:232-6. [PMID: 8793216 DOI: 10.1002/(sici)1098-2353(1996)9:4<232::aid-ca3>3.0.co;2-g] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Laparoscopic repair of inguinal hernias is gaining acceptance in the repertoire of the general surgeon. However, nerve entrapment sequelae have been reported and appear to be higher with the laparoscopic approach. Contributing factors include pelvic variations in nerve pathways and the use of staples. We examined the pelvic relations of the lateral femoral cutaneous nerve (LFCN) to the anterior superior iliac spine (ASIS) and the iliopubic tract (IPT) because of the high morbidity of entrapment of this nerve, despite its low incidence. The LFCN, ASIS, and IPT were identified and their relationships measured in 48 male and 24 female cadavers ranging in age from 61 to 96 yr. The LFCN was located 1.7 (+/- 1.2) cm medial to the ASIS along the IPT and 1.4 (+/- 0.7) cm posterior (deep) to the IPT at this point, with no significant sex differences. The intrapelvic pathway of the LFCN, including its branches, varied widely so that in 18% of these specimens the LFCN was in either the vertical plane of the ASIS (13%) or in the plane of the IPT (5%). In 11% this nerve was within 1 cm of the ASIS. These data indicate that exclusive use of the ASIS as a guide for staple placement may result in entrapment of this nerve or its branches.
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Lefevre JA, Lei Q, Smith-Chant BL, Mullins DB. Multiplication by eye and by ear for Chinese-speaking and English-speaking adults. CANADIAN JOURNAL OF EXPERIMENTAL PSYCHOLOGY = REVUE CANADIENNE DE PSYCHOLOGIE EXPERIMENTALE 2001; 55:277-84. [PMID: 11768852 DOI: 10.1037/h0087374] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
English-speaking (n = 32) and Chinese-speaking adults (n = 32) solved single-digit multiplication problems. In one condition, problems were presented as visual digits (e.g., 8 x 9). In the other condition, problems were presented as auditory number words in the participant's first language (e.g., /eit/ /taimz/ /nain/). Chinese-speaking adults made proportionately more operand-intrusion errors (e.g., 4 x 8 = 24) than English-speaking adults. Both groups made more operand-intrusion errors with auditory than with visual presentation. These findings are similar to those found when participants solve problems presented as visual number words (e.g., eight x nine), suggesting that in both cases the activation of phonological codes interferes with processing.
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Wang R, Goyal R, Lei Q, Essex M, De Gruttola V. Sample size considerations in the design of cluster randomized trials of combination HIV prevention. Clin Trials 2014; 11:309-318. [PMID: 24651566 PMCID: PMC4169770 DOI: 10.1177/1740774514523351] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Background Cluster randomized trials have been utilized to evaluate the effectiveness of HIV prevention strategies on reducing incidence. Design of such studies must take into account possible correlation of outcomes within randomized units. Purpose To discuss power and sample size considerations for cluster randomized trials of combination HIV prevention, using an HIV prevention study in Botswana as an illustration. Methods We introduce a new agent-based model to simulate the community-level impact of a combination prevention strategy and investigate how correlation structure within a community affects the coefficient of variation - an essential parameter in designing a cluster randomized trial. Results We construct collections of sexual networks and then propagate HIV on them to simulate the disease epidemic. Increasing level of sexual mixing between intervention and standard-of-care (SOC) communities reduces the difference in cumulative incidence in the two sets of communities. Fifteen clusters per arm and 500 incidence cohort members per community provide 95% power to detect the projected difference in cumulative HIV incidence between SOC and intervention communities (3.93% and 2.34%) at the end of the third study year, using a coefficient of variation 0.25. Although available formulas for calculating sample size for cluster randomized trials can be derived by assuming an exchangeable correlation structure within clusters, we show that deviations from this assumption do not generally affect the validity of such formulas. Limitations We construct sexual networks based on data from Likoma Island, Malawi, and base disease progression on longitudinal estimates from an incidence cohort in Botswana and in Durban as well as a household survey in Mochudi, Botswana. Network data from Botswana and larger sample sizes to estimate rates of disease progression would be useful in assessing the robustness of our model results. Conclusion Epidemic modeling plays a critical role in planning and evaluating interventions for prevention. Simulation studies allow us to take into consideration available information on sexual network characteristics, such as mixing within and between communities as well as coverage levels for different prevention modalities in the combination prevention package.
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Novitsky V, Moyo S, Lei Q, DeGruttola V, Essex M. Importance of Viral Sequence Length and Number of Variable and Informative Sites in Analysis of HIV Clustering. AIDS Res Hum Retroviruses 2015; 31:531-42. [PMID: 25560745 DOI: 10.1089/aid.2014.0211] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
To improve the methodology of HIV cluster analysis, we addressed how analysis of HIV clustering is associated with parameters that can affect the outcome of viral clustering. The extent of HIV clustering and tree certainty was compared between 401 HIV-1C near full-length genome sequences and subgenomic regions retrieved from the LANL HIV Database. Sliding window analysis was based on 99 windows of 1,000 bp and 45 windows of 2,000 bp. Potential associations between the extent of HIV clustering and sequence length and the number of variable and informative sites were evaluated. The near full-length genome HIV sequences showed the highest extent of HIV clustering and the highest tree certainty. At the bootstrap threshold of 0.80 in maximum likelihood (ML) analysis, 58.9% of near full-length HIV-1C sequences but only 15.5% of partial pol sequences (ViroSeq) were found in clusters. Among HIV-1 structural genes, pol showed the highest extent of clustering (38.9% at a bootstrap threshold of 0.80), although it was significantly lower than in the near full-length genome sequences. The extent of HIV clustering was significantly higher for sliding windows of 2,000 bp than 1,000 bp. We found a strong association between the sequence length and proportion of HIV sequences in clusters, and a moderate association between the number of variable and informative sites and the proportion of HIV sequences in clusters. In HIV cluster analysis, the extent of detectable HIV clustering is directly associated with the length of viral sequences used, as well as the number of variable and informative sites. Near full-length genome sequences could provide the most informative HIV cluster analysis. Selected subgenomic regions with a high extent of HIV clustering and high tree certainty could also be considered as a second choice.
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Lei Q, Lv LJ, Zhang BY, Wen JY, Liu GC, Lin XH, Niu JM. Ante-partum and post-partum markers of metabolic syndrome in pre-eclampsia. J Hum Hypertens 2010; 25:11-7. [DOI: 10.1038/jhh.2010.29] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Wirth KE, Gaolathe T, Pretorius Holme M, Mmalane M, Kadima E, Chakalisa U, Manyake K, Matildah Mbikiwa A, Simon SV, Letlhogile R, Mukokomani K, van Widenfelt E, Moyo S, Bennett K, Leidner J, Powis KM, Lebelonyane R, Alwano MG, Jarvis J, Dryden-Peterson SL, Kgathi C, Moore J, Bachanas P, Raizes E, Abrams W, Block L, Sento B, Novitsky V, El-Halabi S, Marukutira T, Mills LA, Sexton C, Pals S, Shapiro RL, Wang R, Lei Q, DeGruttola V, Makhema J, Essex M, Lockman S, Tchetgen Tchetgen EJ. Population uptake of HIV testing, treatment, viral suppression, and male circumcision following a community-based intervention in Botswana (Ya Tsie/BCPP): a cluster-randomised trial. Lancet HIV 2020; 7:e422-e433. [PMID: 32504575 PMCID: PMC7864245 DOI: 10.1016/s2352-3018(20)30103-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 03/20/2020] [Accepted: 03/20/2020] [Indexed: 01/10/2023]
Abstract
BACKGROUND In settings with high HIV prevalence and treatment coverage, such as Botswana, it is unknown whether uptake of HIV prevention and treatment interventions can be increased further. We sought to determine whether a community-based intervention to identify and rapidly treat people living with HIV, and support male circumcision could increase population levels of HIV diagnosis, treatment, viral suppression, and male circumcision in Botswana. METHODS The Ya Tsie Botswana Combination Prevention Project study was a pair-matched cluster-randomised trial done in 30 communities across Botswana done from Oct 30, 2013, to June 30, 2018. 15 communities were randomly assigned to receive HIV prevention and treatment interventions, including enhanced HIV testing, earlier antiretroviral therapy (ART), and strengthened male circumcision services, and 15 received standard of care. The first primary endpoint of HIV incidence has already been reported. In this Article, we report findings for the second primary endpoint of population uptake of HIV prevention services, as measured by proportion of people known to be HIV-positive or tested HIV-negative in the preceding 12 months; proportion of people living with HIV diagnosed and on ART; proportion of people living with HIV on ART with viral suppression; and proportion of HIV-negative men circumcised. A longitudinal cohort of residents aged 16-64 years from a random, approximately 20% sample of households across the 15 communities was enrolled to assess baseline uptake of study outcomes; we also administered an end-of-study survey to all residents not previously enrolled in the longitudinal cohort to provide study end coverage estimates. Differences in intervention uptake over time by randomisation group were tested via paired Student's t test. The study has been completed and is registered with ClinicalTrials.gov (NCT01965470). FINDINGS In the six communities participating in the end-of-study survey, 2625 residents (n=1304 from standard-of-care communities, n=1321 from intervention communities) were enrolled into the 20% longitudinal cohort at baseline from Oct 30, 2013, to Nov 24, 2015. In the same communities, 10 791 (86%) of 12 489 eligible enumerated residents not previously enrolled in the longitudinal cohort participated in the end-of-study survey from March 30, 2017, to Feb 25, 2018 (5896 in intervention and 4895 in standard-of-care communities). At study end, in intervention communities, 1228 people living with HIV (91% of 1353) were on ART; 1166 people living with HIV (88% of 1321 with available viral load) were virally suppressed, and 673 HIV-negative men (40% of 1673) were circumcised in intervention communities. After accounting for baseline differences, at study end the proportion of people living with HIV who were diagnosed was significantly higher in intervention communities (absolute increase of 9% to 93%) compared with standard-of-care communities (absolute increase of 2% to 88%; prevalence ratio [PR] 1·08 [95% CI 1·02-1·14], p=0·032). Population levels of ART, viral suppression, and male circumcision increased from baseline in both groups, with greater increases in intervention communities (ART PR 1·12 [95% CI 1·07-1·17], p=0·018; viral suppression 1·13 [1·09-1·17], p=0·017; male circumcision 1·26 [1·17-1·35], p=0·029). INTERPRETATION It is possible to achieve very high population levels of HIV testing and treatment in a high-prevalence setting. Maintaining these coverage levels over the next decade could substantially reduce HIV transmission and potentially eliminate the epidemic in these areas. FUNDING US President's Emergency Plan for AIDS Relief through the Centers for Disease Control and Prevention.
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