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1.
Cell ; 184(3): 810-826.e23, 2021 02 04.
Article in English | MEDLINE | ID: mdl-33406409

ABSTRACT

Development of the human intestine is not well understood. Here, we link single-cell RNA sequencing and spatial transcriptomics to characterize intestinal morphogenesis through time. We identify 101 cell states including epithelial and mesenchymal progenitor populations and programs linked to key morphogenetic milestones. We describe principles of crypt-villus axis formation; neural, vascular, mesenchymal morphogenesis, and immune population of the developing gut. We identify the differentiation hierarchies of developing fibroblast and myofibroblast subtypes and describe diverse functions for these including as vascular niche cells. We pinpoint the origins of Peyer's patches and gut-associated lymphoid tissue (GALT) and describe location-specific immune programs. We use our resource to present an unbiased analysis of morphogen gradients that direct sequential waves of cellular differentiation and define cells and locations linked to rare developmental intestinal disorders. We compile a publicly available online resource, spatio-temporal analysis resource of fetal intestinal development (STAR-FINDer), to facilitate further work.


Subject(s)
Intestines/cytology , Intestines/growth & development , Single-Cell Analysis , Endothelial Cells/cytology , Enteric Nervous System/cytology , Fetus/embryology , Fibroblasts/cytology , Humans , Immunity , Intestinal Diseases/congenital , Intestinal Diseases/pathology , Intestinal Mucosa/growth & development , Intestines/blood supply , Ligands , Mesoderm/cytology , Neovascularization, Physiologic , Pericytes/cytology , Stem Cells/cytology , Time Factors , Transcription Factors/metabolism
2.
Nature ; 630(8016): 335-339, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38811734

ABSTRACT

Traditionally, magnetic solids are divided into two main classes-ferromagnets and antiferromagnets with parallel and antiparallel spin orders, respectively. Although normally the antiferromagnets have zero magnetization, in some of them an additional antisymmetric spin-spin interaction arises owing to a strong spin-orbit coupling and results in canting of the spins, thereby producing net magnetization. The canted antiferromagnets combine antiferromagnetic order with phenomena typical of ferromagnets and hold great potential for spintronics and magnonics1-5. In this way, they can be identified as closely related to the recently proposed new class of magnetic materials called altermagnets6-9. Altermagnets are predicted to have strong magneto-optical effects, terahertz-frequency spin dynamics and degeneracy lifting for chiral spin waves10 (that is, all of the effects present in the canted antiferromagnets11,12). Here, by utilizing these unique phenomena, we demonstrate a new functionality of canted spin order for magnonics and show that it facilitates mechanisms converting a magnon at the centre of the Brillouin zone into propagating magnons using nonlinear magnon-magnon interactions activated by an ultrafast laser pulse. Our experimental findings supported by theoretical analysis show that the mechanism is enabled by the spin canting.

3.
Nature ; 629(8011): 307-310, 2024 May.
Article in English | MEDLINE | ID: mdl-38710931

ABSTRACT

Despite its Earth-like size and source material1,2, Venus is extremely dry3,4, indicating near-total water loss to space by means of hydrogen outflow from an ancient, steam-dominated atmosphere5,6. Such hydrodynamic escape likely removed most of an initial Earth-like 3-km global equivalent layer (GEL) of water but cannot deplete the atmosphere to the observed 3-cm GEL because it shuts down below about 10-100 m GEL5,7. To complete Venus water loss, and to produce the observed bulk atmospheric enrichment in deuterium of about 120 times Earth8,9, nonthermal H escape mechanisms still operating today are required10,11. Early studies identified these as resonant charge exchange12-14, hot oxygen impact15,16 and ion outflow17,18, establishing a consensus view of H escape10,19 that has since received only minimal updates20. Here we show that this consensus omits the most important present-day H loss process, HCO+ dissociative recombination. This process nearly doubles the Venus H escape rate and, consequently, doubles the amount of present-day volcanic water outgassing and/or impactor infall required to maintain a steady-state atmospheric water abundance. These higher loss rates resolve long-standing difficulties in simultaneously explaining the measured abundance and isotope ratio of Venusian water21,22 and would enable faster desiccation in the wake of speculative late ocean scenarios23. Design limitations prevented past Venus missions from measuring both HCO+ and the escaping hydrogen produced by its recombination; future spacecraft measurements are imperative.

4.
Nature ; 628(8009): 741-745, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38658686

ABSTRACT

Extensive efforts have been undertaken to combine superconductivity and the quantum Hall effect so that Cooper-pair transport between superconducting electrodes in Josephson junctions is mediated by one-dimensional edge states1-6. This interest has been motivated by prospects of finding new physics, including topologically protected quasiparticles7-9, but also extends into metrology and device applications10-13. So far it has proven challenging to achieve detectable supercurrents through quantum Hall conductors2,3,6. Here we show that domain walls in minimally twisted bilayer graphene14-18 support exceptionally robust proximity superconductivity in the quantum Hall regime, allowing Josephson junctions to operate in fields close to the upper critical field of superconducting electrodes. The critical current is found to be non-oscillatory and practically unchanging over the entire range of quantizing fields, with its value being limited by the quantum conductance of ballistic, strictly one-dimensional, electronic channels residing within the domain walls. The system described is unique in its ability to support Andreev bound states at quantizing fields and offers many interesting directions for further exploration.

5.
Cell ; 148(1-2): 99-111, 2012 Jan 20.
Article in English | MEDLINE | ID: mdl-22265405

ABSTRACT

The replication of eukaryotic chromosomes is organized temporally and spatially within the nucleus through epigenetic regulation of replication origin function. The characteristic initiation timing of specific origins is thought to reflect their chromatin environment or sub-nuclear positioning, however the mechanism remains obscure. Here we show that the yeast Forkhead transcription factors, Fkh1 and Fkh2, are global determinants of replication origin timing. Forkhead regulation of origin timing is independent of local levels or changes of transcription. Instead, we show that Fkh1 and Fkh2 are required for the clustering of early origins and their association with the key initiation factor Cdc45 in G1 phase, suggesting that Fkh1 and Fkh2 selectively recruit origins to emergent replication factories. Fkh1 and Fkh2 bind Fkh-activated origins, and interact physically with ORC, providing a plausible mechanism to cluster origins. These findings add a new dimension to our understanding of the epigenetic basis for differential origin regulation and its connection to chromosomal domain organization.


Subject(s)
Cell Cycle Proteins/metabolism , Forkhead Transcription Factors/metabolism , Replication Origin , Saccharomyces cerevisiae Proteins/metabolism , Saccharomyces cerevisiae/metabolism , DNA-Binding Proteins/metabolism , G1 Phase , Nuclear Proteins/metabolism , Saccharomyces cerevisiae/cytology , Saccharomyces cerevisiae/genetics , Transcription, Genetic
6.
Proc Natl Acad Sci U S A ; 121(39): e2411428121, 2024 Sep 24.
Article in English | MEDLINE | ID: mdl-39284068

ABSTRACT

Long COVID occurs in a small but important minority of patients following COVID-19, reducing quality of life and contributing to healthcare burden. Although research into underlying mechanisms is evolving, immunity is understudied. SARS-CoV-2-specific T cell responses are of key importance for viral clearance and COVID-19 recovery. However, in long COVID, the establishment and persistence of SARS-CoV-2-specific T cells are far from clear, especially beyond 12 mo postinfection and postvaccination. We defined ex vivo antigen-specific B cell and T cell responses and their T cell receptors (TCR) repertoires across 2 y postinfection in people with long COVID. Using 13 SARS-CoV-2 peptide-HLA tetramers, spanning 11 HLA allotypes, as well as spike and nucleocapsid probes, we tracked SARS-CoV-2-specific CD8+ and CD4+ T cells and B-cells in individuals from their first SARS-CoV-2 infection through primary vaccination over 24 mo. The frequencies of ORF1a- and nucleocapsid-specific T cells and B cells remained stable over 24 mo. Spike-specific CD8+ and CD4+ T cells and B cells were boosted by SARS-CoV-2 vaccination, indicating immunization, in fully recovered and people with long COVID, altered the immunodominance hierarchy of SARS-CoV-2 T cell epitopes. Meanwhile, influenza-specific CD8+ T cells were stable across 24 mo, suggesting no bystander-activation. Compared to total T cell populations, SARS-CoV-2-specific T cells were enriched for central memory phenotype, although the proportion of central memory T cells decreased following acute illness. Importantly, TCR repertoire composition was maintained throughout long COVID, including postvaccination, to 2 y postinfection. Overall, we defined ex vivo SARS-CoV-2-specific B cells and T cells to understand primary and recall responses, providing key insights into antigen-specific responses in people with long COVID.


Subject(s)
CD8-Positive T-Lymphocytes , COVID-19 , Receptors, Antigen, T-Cell , SARS-CoV-2 , Humans , CD8-Positive T-Lymphocytes/immunology , SARS-CoV-2/immunology , COVID-19/immunology , Receptors, Antigen, T-Cell/immunology , Receptors, Antigen, T-Cell/metabolism , Epitopes, T-Lymphocyte/immunology , Spike Glycoprotein, Coronavirus/immunology , Middle Aged , Male , Female , Post-Acute COVID-19 Syndrome , Phenotype , B-Lymphocytes/immunology , Immunologic Memory/immunology , Coronavirus Nucleocapsid Proteins/immunology , Aged
7.
J Biol Chem ; 300(1): 105583, 2024 Jan.
Article in English | MEDLINE | ID: mdl-38141770

ABSTRACT

Membrane polyphosphoinositides (PPIs) are lipid-signaling molecules that undergo metabolic turnover and influence a diverse range of cellular functions. PPIs regulate the activity and/or spatial localization of a number of actin-binding proteins (ABPs) through direct interactions; however, it is much less clear whether ABPs could also be an integral part in regulating PPI signaling. In this study, we show that ABP profilin1 (Pfn1) is an important molecular determinant of the cellular content of PI(4,5)P2 (the most abundant PPI in cells). In growth factor (EGF) stimulation setting, Pfn1 depletion does not impact PI(4,5)P2 hydrolysis but enhances plasma membrane (PM) enrichment of PPIs that are produced downstream of activated PI3-kinase, including PI(3,4,5)P3 and PI(3,4)P2, the latter consistent with increased PM recruitment of SH2-containing inositol 5' phosphatase (SHIP2) (a key enzyme for PI(3,4)P2 biosynthesis). Although Pfn1 binds to PPIs in vitro, our data suggest that Pfn1's affinity to PPIs and PM presence in actual cells, if at all, is negligible, suggesting that Pfn1 is unlikely to directly compete with SHIP2 for binding to PM PPIs. Additionally, we provide evidence for Pfn1's interaction with SHIP2 in cells and modulation of this interaction upon EGF stimulation, raising an alternative possibility of Pfn1 binding as a potential restrictive mechanism for PM recruitment of SHIP2. In conclusion, our findings challenge the dogma of Pfn1's binding to PM by PPI interaction, uncover a previously unrecognized role of Pfn1 in PI(4,5)P2 homeostasis and provide a new mechanistic avenue of how an ABP could potentially impact PI3K signaling byproducts in cells through lipid phosphatase control.


Subject(s)
Phosphatidylinositols , Profilins , Epidermal Growth Factor/metabolism , Phosphatidylinositol 3-Kinases/metabolism , Phosphatidylinositol-3,4,5-Trisphosphate 5-Phosphatases/metabolism , Phosphatidylinositols/metabolism , Humans , HEK293 Cells , Profilins/metabolism
8.
J Cell Sci ; 136(16)2023 08 15.
Article in English | MEDLINE | ID: mdl-37534432

ABSTRACT

The lipid molecule phosphatidylinositol (4,5)-bisphosphate [PI(4,5)P2] controls all aspects of plasma membrane (PM) function in animal cells, from its selective permeability to the attachment of the cytoskeleton. Although disruption of PI(4,5)P2 is associated with a wide range of diseases, it remains unclear how cells sense and maintain PI(4,5)P2 levels to support various cell functions. Here, we show that the PIP4K family of enzymes, which synthesize PI(4,5)P2 via a minor pathway, also function as sensors of tonic PI(4,5)P2 levels. PIP4Ks are recruited to the PM by elevated PI(4,5)P2 levels, where they inhibit the major PI(4,5)P2-synthesizing PIP5Ks. Perturbation of this simple homeostatic mechanism reveals differential sensitivity of PI(4,5)P2-dependent signaling to elevated PI(4,5)P2 levels. These findings reveal that a subset of PI(4,5)P2-driven functions might drive disease associated with disrupted PI(4,5)P2 homeostasis.


Subject(s)
Phosphatidylinositol 4,5-Diphosphate , Signal Transduction , Animals , Phosphatidylinositol 4,5-Diphosphate/metabolism , Signal Transduction/physiology , Cell Membrane/metabolism , Phosphatidylinositols/metabolism , Homeostasis
9.
PLoS Biol ; 20(4): e3001602, 2022 04.
Article in English | MEDLINE | ID: mdl-35389984

ABSTRACT

Gene expression in endosperm-a seed tissue that mediates transfer of maternal resources to offspring-is under complex epigenetic control. We show here that plant-specific RNA polymerase IV (Pol IV) mediates parental control of endosperm gene expression. Pol IV is required for the production of small interfering RNAs that typically direct DNA methylation. We compared small RNAs (sRNAs), DNA methylation, and mRNAs in Arabidopsis thaliana endosperm from heterozygotes produced by reciprocally crossing wild-type (WT) plants to Pol IV mutants. We find that maternally and paternally acting Pol IV induce distinct effects on endosperm. Loss of maternal or paternal Pol IV impacts sRNAs and DNA methylation at different genomic sites. Strikingly, maternally and paternally acting Pol IV have antagonistic impacts on gene expression at some loci, divergently promoting or repressing endosperm gene expression. Antagonistic parent-of-origin effects have only rarely been described and are consistent with a gene regulatory system evolving under parental conflict.


Subject(s)
Arabidopsis Proteins , Arabidopsis , Arabidopsis/genetics , Arabidopsis/metabolism , Arabidopsis Proteins/genetics , Arabidopsis Proteins/metabolism , DNA Methylation/genetics , DNA-Directed RNA Polymerases/genetics , DNA-Directed RNA Polymerases/metabolism , Endosperm/genetics , Endosperm/metabolism , Gene Expression Regulation, Plant , Genomic Imprinting , Plants/genetics , RNA, Plant/metabolism , RNA, Small Interfering/metabolism
10.
Nature ; 569(7756): 383-387, 2019 05.
Article in English | MEDLINE | ID: mdl-31092937

ABSTRACT

Future information technology demands ever-faster, low-loss quantum control. Intense light fields have facilitated milestones along this way, including the induction of novel states of matter1-3, ballistic acceleration of electrons4-7 and coherent flipping of the valley pseudospin8. These dynamics leave unique 'fingerprints', such as characteristic bandgaps or high-order harmonic radiation. The fastest and least dissipative way of switching the technologically most important quantum attribute-the spin-between two states separated by a potential barrier is to trigger an all-coherent precession. Experimental and theoretical studies with picosecond electric and magnetic fields have suggested this possibility9-11, yet observing the actual spin dynamics has remained out of reach. Here we show that terahertz electromagnetic pulses allow coherent steering of spins over a potential barrier, and we report the corresponding temporal and spectral fingerprints. This goal is achieved by coupling spins in antiferromagnetic TmFeO3 (thulium orthoferrite) with the locally enhanced terahertz electric field of custom-tailored antennas. Within their duration of one picosecond, the intense terahertz pulses abruptly change the magnetic anisotropy and trigger a large-amplitude ballistic spin motion. A characteristic phase flip, an asymmetric splitting of the collective spin resonance and a long-lived offset of the Faraday signal are hallmarks of coherent spin switching into adjacent potential minima, in agreement with numerical simulations. The switchable states can be selected by an external magnetic bias. The low dissipation and the antenna's subwavelength spatial definition could facilitate scalable spin devices operating at terahertz rates.

11.
Mol Cell ; 67(2): 348-354.e4, 2017 Jul 20.
Article in English | MEDLINE | ID: mdl-28732207

ABSTRACT

We have combined a machine-learning approach with other strategies to optimize knockout efficiency with the CRISPR/Cas9 system. In addition, we have developed a multiplexed sgRNA expression strategy that promotes the functional ablation of single genes and allows for combinatorial targeting. These strategies have been combined to design and construct a genome-wide, sequence-verified, arrayed CRISPR library. This resource allows single-target or combinatorial genetic screens to be carried out at scale in a multiplexed or arrayed format. By conducting parallel loss-of-function screens, we compare our approach to existing sgRNA design and expression strategies.


Subject(s)
CRISPR-Associated Proteins/genetics , CRISPR-Cas Systems , Endonucleases/genetics , Gene Silencing , Gene Targeting/methods , RNA, Guide, Kinetoplastida/genetics , Algorithms , CRISPR-Associated Proteins/metabolism , Endonucleases/metabolism , Gene Library , High-Throughput Nucleotide Sequencing , Humans , K562 Cells , Machine Learning , RNA, Guide, Kinetoplastida/metabolism , Transfection
12.
Proc Natl Acad Sci U S A ; 119(12): e2100670119, 2022 03 22.
Article in English | MEDLINE | ID: mdl-35286200

ABSTRACT

Squamous cell carcinoma of the head and neck (SCCHN) is a devastating disease that continues to have low cure rates despite the recent advances in therapies. Cisplatin is the most used chemotherapy agent, and treatment failure is largely driven by resistance to this drug. Amplification of chromosomal band 11q13 occurs in ∼30% of SCCHN tumors. This region harbors the ANO1 gene that encodes the TMEM16A ion channel, which is responsible for calcium-activated chloride transport in epithelial tissues. TMEM16A overexpression is associated with cisplatin resistance, and high TMEM16A levels correlate with decreased survival. However, the mechanistic underpinning of this effect remains unknown. Lysosomal biogenesis and exocytosis have been implicated in cancer because of their roles in the clearance of damaged organelles and exocytosis of chemotherapeutic drugs and toxins. Here, we show that TMEM16A overexpression promotes lysosomal biogenesis and exocytosis, which is consistent with the expulsion of intracellular cisplatin. Using a combination of genetic and pharmacologic approaches, we find that TMEM16A promotes lysosomal flux in a manner that requires reactive oxygen species, TRPML1, and the activation of the ß-catenin­melanocyte-inducing transcription factor pathway. The lysosomal inhibitor hydroxychloroquine (HCQ) synergizes with cisplatin in killing SCCHN cells in vitro. Using a murine model of SCCHN, we show that HCQ and cisplatin retard the growth of cisplatin-resistant patient-derived xenografts in vivo. We propose that TMEM16A enables cell survival by the up-regulation of lysosomal sequestration and exocytosis of the cytotoxic drugs. These results uncover a model of treatment for resistance in cancer, its reversal, and a role for TMEM16A.


Subject(s)
Anoctamin-1 , Antineoplastic Agents , Cisplatin , Head and Neck Neoplasms , Neoplasm Proteins , Anoctamin-1/genetics , Anoctamin-1/metabolism , Antineoplastic Agents/pharmacology , Cell Line, Tumor , Chloride Channels , Cisplatin/pharmacology , Humans , Lysosomes/metabolism , Neoplasm Proteins/metabolism
13.
Diabetologia ; 67(3): 528-546, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38127123

ABSTRACT

AIMS/HYPOTHESIS: Diabetes mellitus is associated with impaired insulin secretion, often aggravated by oversecretion of glucagon. Therapeutic interventions should ideally correct both defects. Glucagon-like peptide 1 (GLP-1) has this capability but exactly how it exerts its glucagonostatic effect remains obscure. Following its release GLP-1 is rapidly degraded from GLP-1(7-36) to GLP-1(9-36). We hypothesised that the metabolite GLP-1(9-36) (previously believed to be biologically inactive) exerts a direct inhibitory effect on glucagon secretion and that this mechanism becomes impaired in diabetes. METHODS: We used a combination of glucagon secretion measurements in mouse and human islets (including islets from donors with type 2 diabetes), total internal reflection fluorescence microscopy imaging of secretory granule dynamics, recordings of cytoplasmic Ca2+ and measurements of protein kinase A activity, immunocytochemistry, in vivo physiology and GTP-binding protein dissociation studies to explore how GLP-1 exerts its inhibitory effect on glucagon secretion and the role of the metabolite GLP-1(9-36). RESULTS: GLP-1(7-36) inhibited glucagon secretion in isolated islets with an IC50 of 2.5 pmol/l. The effect was particularly strong at low glucose concentrations. The degradation product GLP-1(9-36) shared this capacity. GLP-1(9-36) retained its glucagonostatic effects after genetic/pharmacological inactivation of the GLP-1 receptor. GLP-1(9-36) also potently inhibited glucagon secretion evoked by ß-adrenergic stimulation, amino acids and membrane depolarisation. In islet alpha cells, GLP-1(9-36) led to inhibition of Ca2+ entry via voltage-gated Ca2+ channels sensitive to ω-agatoxin, with consequential pertussis-toxin-sensitive depletion of the docked pool of secretory granules, effects that were prevented by the glucagon receptor antagonists REMD2.59 and L-168049. The capacity of GLP-1(9-36) to inhibit glucagon secretion and reduce the number of docked granules was lost in alpha cells from human donors with type 2 diabetes. In vivo, high exogenous concentrations of GLP-1(9-36) (>100 pmol/l) resulted in a small (30%) lowering of circulating glucagon during insulin-induced hypoglycaemia. This effect was abolished by REMD2.59, which promptly increased circulating glucagon by >225% (adjusted for the change in plasma glucose) without affecting pancreatic glucagon content. CONCLUSIONS/INTERPRETATION: We conclude that the GLP-1 metabolite GLP-1(9-36) is a systemic inhibitor of glucagon secretion. We propose that the increase in circulating glucagon observed following genetic/pharmacological inactivation of glucagon signalling in mice and in people with type 2 diabetes reflects the removal of GLP-1(9-36)'s glucagonostatic action.


Subject(s)
Diabetes Mellitus, Type 2 , Hypoglycemia , Islets of Langerhans , Peptide Fragments , Humans , Glucagon/metabolism , Diabetes Mellitus, Type 2/metabolism , Glucagon-Like Peptide 1/metabolism , Islets of Langerhans/metabolism , Hypoglycemia/metabolism , Insulin/metabolism
14.
Clin Infect Dis ; 2024 Oct 01.
Article in English | MEDLINE | ID: mdl-39352692

ABSTRACT

BACKGROUND: Our study addresses the sepsis research gap in lower middle-income countries, notably India. Here, we investigate community-acquired sepsis comprehensively and explore the impact of tropical microbiology on aetiology and outcomes. METHODS: MARS-India was a prospective observational study from Dec-2018 to Sep-2022 in a tertiary-care hospital in South India. Adult patients within 24hrs of ICU admission meeting the Sepsis 3.0 definition were enrolled, with 6-months follow-up (http://clinicaltrials.gov number NCT03727243). RESULTS: Over 4000 patients were screened on ICU admission, with 1000 unique patients meeting the inclusion criteria. Median age was 55 years (IQR: 44-65) with a male preponderance (66%). Almost half the cohort resided in villages (46.5%) and 74.6% worked in the primary sector. Mortality in-hospital was 24.1%. Overall, ∼54% had confirmed microbiological diagnosis. Over 18% had a viral cause of sepsis. Surprisingly, we identified leptospirosis (10.6%), scrub typhus (4.1%), dengue (3.7%) and Kyasanur forest disease (1.6%) as notables causes of sepsis. All these infections showed seasonal variation around the monsoon. In community-acquired infections we observed substantial resistance to 3rd generation cephalosporins and carbapenems. CONCLUSIONS: In India, sepsis disproportionally affects a younger and lower socio-economic demographic, yielding high mortality. Tropical and viral sepsis carry a significant burden. Analyzing local data, we pinpoint priorities for public health and resources, offering valuable insights for global sepsis research.

15.
Ann Oncol ; 35(8): 739-746, 2024 Aug.
Article in English | MEDLINE | ID: mdl-38754780

ABSTRACT

BACKGROUND: Neoadjuvant dabrafenib plus trametinib has a high pathological response rate and impressive short-term survival in patients with resectable stage III melanoma. We report 5-year outcomes from the phase II NeoCombi trial. PATIENTS AND METHODS: NeoCombi (NCT01972347) was a single-arm, open-label, single-centre, phase II trial. Eligible patients were adults (aged ≥18 years) with histologically confirmed, resectable, RECIST-measurable, American Joint Committee on Cancer seventh edition clinical stage IIIB-C BRAF V600E/K-mutant melanoma and Eastern Cooperative Oncology Group performance status ≤1. Patients received 52 weeks of treatment with dabrafenib 150 mg (orally twice per day) plus trametinib 2 mg (orally once per day), with complete resection of the pre-therapy tumour bed at week 12. RESULTS: Between 20 August 2014 and 19 April 2017, 35 patients were enrolled. At data cut-off (17 August 2021), the median follow-up was 60 months [95% confidence interval (CI) 56-72 months]. Overall, 21 of 35 (60%) patients recurred, including 12 (57%) with first recurrence in locoregional sites (followed by later distant recurrence in 6) and 9 (43%) with first recurrence in distant sites, including 3 in the brain. Most recurrences occurred within 2 years, with no recurrences beyond 3 years. At 5 years, recurrence-free survival (RFS) was 40% (95% CI 27% to 60%), distant metastasis-free survival (DMFS) was 57% (95% CI 42% to 76%), and overall survival was 80% (95% CI 67% to 94%). Five-year survival outcomes were stratified by pathological response: RFS was 53% with pathological complete response (pCR) versus 28% with non-pCR (P = 0.087), DMFS was 59% versus 55% (P = 0.647), and overall survival was 88% versus 71% (P = 0.205), respectively. CONCLUSIONS: Neoadjuvant dabrafenib plus trametinib has high pathological response rates in clinical stage III melanoma, but low rates of RFS, similar to those achieved with adjuvant targeted therapy alone. Patients with a pCR to dabrafenib plus trametinib still had a high risk of recurrence, unlike that seen with immunotherapy where recurrences are rare.


Subject(s)
Antineoplastic Combined Chemotherapy Protocols , Imidazoles , Melanoma , Neoadjuvant Therapy , Neoplasm Staging , Oximes , Pyridones , Pyrimidinones , Humans , Oximes/administration & dosage , Melanoma/drug therapy , Melanoma/pathology , Melanoma/mortality , Pyrimidinones/administration & dosage , Pyridones/administration & dosage , Imidazoles/administration & dosage , Female , Male , Middle Aged , Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Aged , Adult , Skin Neoplasms/drug therapy , Skin Neoplasms/pathology , Skin Neoplasms/mortality , Follow-Up Studies
16.
BMC Biotechnol ; 24(1): 32, 2024 May 15.
Article in English | MEDLINE | ID: mdl-38750469

ABSTRACT

ß-TCP ceramics are versatile bone substitute materials and show many interactions with cells of the monocyte-macrophage-lineage. The possibility of monocytes entering microporous ß-TCP ceramics has however not yet been researched. In this study, we used a model approach to investigate whether monocytes might enter ß-TCP, providing a possible explanation for the origin of CD68-positive osteoclast-like giant cells found in earlier works.We used flow chambers to unidirectionally load BC, PRP, or PPP into slice models of either 2 mm or 6 mm ß-TCP. Immunofluorescence for CD68 and live/dead staining was performed after the loading process.Our results show that monocytes were present in a relevant number of PRP and BC slices representing the inside of our 2 mm slice model and also present on the actual inside of our 6 mm model. For PPP, monocytes were not found beyond the surface in either model.Our results indicate the possibility of a new and so far neglected constituent in ß-TCP degradation, perhaps causing the process of ceramic degradation also starting from inside the ceramics as opposed to the current understanding. We also demonstrated flow chambers as a possible new in vitro model for interactions between blood and ß-TCP.


Subject(s)
Calcium Phosphates , Ceramics , Monocytes , Monocytes/cytology , Ceramics/chemistry , Calcium Phosphates/chemistry , Humans , Bone Substitutes/chemistry , Antigens, CD/metabolism , Antigens, Differentiation, Myelomonocytic/metabolism , Porosity
17.
Small ; 20(3): e2304547, 2024 Jan.
Article in English | MEDLINE | ID: mdl-37621039

ABSTRACT

The electrogeneration of hydrogen peroxide (H2 O2 ) via the oxygen reduction reaction is a crucial process for advanced water treatment technologies. While significant effort is being devoted to developing highly reactive materials, gas provision systems used in these processes are receiving less attention. Here, using oxygen nanobubbles to improve the gas efficiency of the electrogeneration of H2 O2 is proposed. Aeration with nanobubbles is compared to aeration with macrobubbles under an identical experimental set-up, with nanobubbles showing a much higher gas-liquid volumetric mass transfer coefficient (KL a) of 2.6 × 10-2 min-1 compared to 2.7 × 10-4 min-1 for macrobubbles. Consequently, nanobubbles exhibit a much higher gas efficiency using 60% of O2 delivered to the system compared to 0.19% for macrobubbles. Further, it is observed that the electrogeneration of H2 O2 using carbon felt electrodes is enhanced using nanobubbles. Under the same dissolved oxygen levels, nanobubbles boost the reaction yield to 84%, while macrobubbles yield only 53.8%. To the authors' knowledge, this is the first study to investigate the use of nanobubbles in electrochemical reactions and demonstrate their ability to enhance gas efficiency and electrocatalytic response. These findings have important implications for developing more efficient chemical and electrochemical processes operating under gas-starving systems.

18.
J Antimicrob Chemother ; 79(7): 1547-1554, 2024 07 01.
Article in English | MEDLINE | ID: mdl-38727613

ABSTRACT

INTRODUCTION: Post-kala-azar dermal leishmaniasis (PKDL) arises as a dermal complication following a visceral leishmaniasis (VL) infection. Current treatment options for PKDL are unsatisfactory, and there is a knowledge gap regarding the distribution of antileishmanial compounds within human skin. The present study investigated the skin distribution of miltefosine in PKDL patients, with the aim to improve the understanding of the pharmacokinetics at the skin target site in PKDL. METHODS: Fifty-two PKDL patients underwent treatment with liposomal amphotericin B (20 mg/kg) plus miltefosine (allometric dosing) for 21 days. Plasma concentrations of miltefosine were measured on study days 8, 15, 22 and 30, while a punch skin biopsy was taken on day 22. A physiologically based pharmacokinetic (PBPK) model was developed to evaluate the distribution of miltefosine into the skin. RESULTS: Following the allometric weight-based dosing regimen, median miltefosine concentrations on day 22 were 43.73 µg/g (IQR: 21.94-60.65 µg/g) in skin and 33.29 µg/mL (IQR: 25.9-42.58 µg/mL) in plasma. The median individual concentration ratio of skin to plasma was 1.19 (IQR: 0.79-1.9). In 87% (45/52) of patients, skin exposure was above the suggested EC90 PK target of 10.6 mg/L associated with in vitro susceptibility. Simulations indicated that the residence time of miltefosine in the skin would be more than 2-fold longer than in plasma, estimated by a mean residence time of 604 versus 266 hours, respectively. CONCLUSION: This study provides the first accurate measurements of miltefosine penetration into the skin, demonstrating substantial exposure and prolonged retention of miltefosine within the skin. These findings support the use of miltefosine in cutaneous manifestations of leishmaniasis. In combination with parasitological and clinical data, these results are critical for the future optimization of combination therapies with miltefosine in the treatment of PKDL.


Subject(s)
Amphotericin B , Antiprotozoal Agents , Leishmaniasis, Cutaneous , Leishmaniasis, Visceral , Phosphorylcholine , Skin , Humans , Phosphorylcholine/analogs & derivatives , Phosphorylcholine/pharmacokinetics , Phosphorylcholine/administration & dosage , Phosphorylcholine/therapeutic use , Antiprotozoal Agents/pharmacokinetics , Antiprotozoal Agents/administration & dosage , Antiprotozoal Agents/therapeutic use , Male , Adult , Leishmaniasis, Cutaneous/drug therapy , Leishmaniasis, Cutaneous/parasitology , Female , Skin/parasitology , Leishmaniasis, Visceral/drug therapy , Middle Aged , Young Adult , Amphotericin B/pharmacokinetics , Amphotericin B/therapeutic use , Amphotericin B/administration & dosage , Adolescent , Asia, Southern
19.
Nat Mater ; 22(4): 459-465, 2023 Apr.
Article in English | MEDLINE | ID: mdl-36658327

ABSTRACT

Spin-valley locking is ubiquitous among transition metal dichalcogenides with local or global inversion asymmetry, in turn stabilizing properties such as Ising superconductivity, and opening routes towards 'valleytronics'. The underlying valley-spin splitting is set by spin-orbit coupling but can be tuned via the application of external magnetic fields or through proximity coupling. However, only modest changes have been realized to date. Here, we investigate the electronic structure of the V-intercalated transition metal dichalcogenide V1/3NbS2 using microscopic-area spatially resolved and angle-resolved photoemission spectroscopy. Our measurements and corresponding density functional theory calculations reveal that the bulk magnetic order induces a giant valley-selective Ising coupling exceeding 50 meV in the surface NbS2 layer, equivalent to application of a ~250 T magnetic field. This energy scale is of comparable magnitude to the intrinsic spin-orbit splittings, and indicates how coupling of local magnetic moments to itinerant states of a transition metal dichalcogenide monolayer provides a powerful route to controlling their valley-spin splittings.

20.
Ophthalmology ; 2024 May 23.
Article in English | MEDLINE | ID: mdl-38795976

ABSTRACT

PURPOSE: The International Classification of Retinopathy of Prematurity, Third Edition (ICROP3), acknowledged that plus-like retinopathy of prematurity (ROP) vascular changes occurs along a spectrum. Historically, clinician-experts demonstrate variable agreement for plus diagnosis. We developed a 9-photograph reference image set for grading plus-like changes and compared intergrader agreement of the set with standard grading with no plus, preplus, and plus disease. DESIGN: Retinal photographic grading and expert consensus opinion. PARTICIPANTS: The development set included 34 international ICROP3 committee members. The validation set included 30 ophthalmologists with ROP expertise (15 ICROP3 committee members and 15 non-ICROP3 members) METHODS: Nine ROP fundus images (P1 through P9) representing increasing degrees of zone I vascular tortuosity and dilation, based on the 34 ICROP3 committee members' gradings and consensus image reviews, were used to establish standard photographs for the plus (P) score. Study participants graded 150 fundus photographs 2 ways, separated by a 1-week washout period: (1) no plus, preplus, or plus disease and (2) choosing the closest P score image. MAIN OUTCOME MEASURES: Intergrader agreement measured by intraclass correlation coefficient. RESULTS: Intergrader agreement was higher using the P score (intraclass correlation coefficient, 0.75; 95% confidence interval, 0.71-0.79) than no plus, preplus, or plus disease (intraclass correlation coefficient, 0.67; 95% confidence interval, 0.62-0.72). Mean ± standard deviation P scores for images with mode gradings of no plus, preplus, and plus disease were 2.5 ± 0.7, 4.8 ± 0.8, and 7.4 ± 0.8, respectively. CONCLUSIONS: Intergrader agreement of plus-like vascular change in ROP using the P score is high. We now incorporate this 9-image reference set into ICROP3 for use in clinician daily practice alongside zone, stage, and plus assessment. P score is not yet meant to replace plus diagnosis for treatment decisions, but its use at our institutions has permitted better comparison between examinations for progression and regression, communication between examiners, and documentation of vascular change without fundus imaging. P score also could provide more detailed ROP classification for clinical trials, consistent with the spectrum of plus-like change that is now formally part of the International Classification of Retinopathy of Prematurity. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

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