Distribution and sea-to-air fluxes of nitrous oxide and methane from a seasonally hypoxic coastal zone in the southeastern Arabian Sea.

The seasonal variability, pathways, and sea-to-air fluxes of nitrous oxide (N2O) and methane (CH4) in the coastal environment, where coastal upwelling and mudbanks co-exist are presented based on the monthly time-series measurements from November 2021 to December 2022. Upwelling-driven hypoxic water's shoreward propagation and persistence were the major factors controlling the N2O concentrations, while the freshwater influx and sedimentary fluxes modulate CH4 concentrations. The N2O concentrations were high during the southwest monsoon (up to 35 nM; 19 ± 8 nM)), followed by spring inter-monsoon (up to 19 nM; 10 ± 5 nM), and lowest during the northeast monsoon (up to 13 nM; 8 ± 2 nM), whereas the CH4 levels were high during the spring inter-monsoon (8.4 to 65 nM), followed by southwest monsoon (6.8 to 53.1 nM) and relatively lower concentrations during the northeast monsoon (3.3 to 32.6 nM). The positive correlations of excess N2O with Apparent Oxygen Utilisation (AOU) and the sum of nitrate and nitrite (NOx) indicate that nitrification is the primary source of N2O in the mudbank regime. The negative correlation of CH4 concentrations with salinity indicates considerable input of CH4 through freshwater influx. CH4 exhibited a highly significant positive correlation with Chlorophyll-a throughout the study period. Furthermore, it displayed a statistically significant positive correlation with phosphate (PO43-) during the northeast monsoon while a strong negative correlation with PO43- during the spring inter-monsoon, pointing towards the role of aerobic CH4 production pathways in the mudbank regime. N2O and CH4 exhibited a contrasting seasonal pattern of sea-to-air fluxes, characterised by the highest N2O fluxes during the southwest monsoon (hypoxia) (13 ± 10 µM m-2 d-1), followed by spring inter-monsoon (12 ± 16 µM m-2 d-1), and the lowest during the northeast monsoon (0.6 ± 3 µM m-2 d-1). Conversely, the highest sea-to-air fluxes of CH4 were noticed during the spring inter-monsoon (74 ± 56 µM m-2 d-1), followed by the southwest monsoon (45 ± 35 µM m-2 d-1), and the lowest values during the northeast monsoon (19 ± 16 µM m-2d-1). Long-term time-series measurements will be invaluable in understanding the longer-term impacts of climate-driven variability on marine biogeochemical cycles in dynamic nearshore systems.

Alicyclic Ring Size Variation of 4-Phenyl-2-naphthoic Acid Derivatives as P2Y14 Receptor Antagonists.

P2Y14 receptor (P2Y14R) is activated by extracellular UDP-glucose, a damage-associated molecular pattern that promotes inflammation in the kidney, lung, fat tissue, and elsewhere. Thus, selective P2Y14R antagonists are potentially useful for inflammatory and metabolic diseases. The piperidine ring size of potent, competitive P2Y14R antagonist (4-phenyl-2-naphthoic acid derivative) PPTN 1 was varied from 4- to 8-membered rings, with bridging/functional substitution. Conformationally and sterically modified isosteres included N-containing spirocyclic (6-9), fused (11-13), and bridged (14, 15) or large (16-20) ring systems, either saturated or containing alkene or hydroxy/methoxy groups. The alicyclic amines displayed structural preference. An α-hydroxyl group increased the affinity of 4-(4-((1R,5S,6r)-6-hydroxy-3-azabicyclo[3.1.1]heptan-6-yl)phenyl)-7-(4-(trifluoromethyl)phenyl)-2-naphthoic acid 15 (MRS4833) compared to 14 by 89-fold. 15 but not its double prodrug 50 reduced airway eosinophilia in a protease-mediated asthma model, and orally administered 15 and prodrugs reversed chronic neuropathic pain (mouse CCI model). Thus, we identified novel drug leads having in vivo efficacy.

Bridged Piperidine Analogues of a High Affinity Naphthalene-Based P2Y14R Antagonist.

High affinity phenyl-piperidine P2Y14R antagonist 1 (PPTN) was modified with piperidine bridging moieties to probe receptor affinity and hydrophobicity. Various 2-azanorbornane, nortropane, isonortropane, isoquinuclidine, and ring-opened cyclopentylamino derivatives preserved human P2Y14R affinity (fluorescence binding assay), and their pharmacophoric overlay was compared. Enantiomeric 2-azabicyclo[2.2.1]hept-5-en-3-one precursors assured stereochemically unambiguous, diverse products. Pure (S,S,S) 2-azanorbornane enantiomer 15 (MRS4738) displayed higher affinity than 1 (3-fold higher affinity than enantiomer 16) and in vivo antihyperallodynic and antiasthmatic activity. Its double prodrug 143 (MRS4815) dramatically reduced lung inflammation in a mouse asthma model. Related lactams 21-24 and dicarboxylate 42 displayed intermediate affinity and enhanced aqueous solubility. Isoquinuclidine 34 (IC50 15.6 nM) and isonortropanol 30 (IC50 21.3 nM) had lower lipophilicity than 1. In general, rigidified piperidine derivatives did not lower lipophilicity dramatically, except those rings with multiple polar groups. P2Y14R molecular modeling based on a P2Y12R structure showed stable and persistent key interactions for compound 15.

Structure-Activity Relationship of Heterocyclic P2Y14 Receptor Antagonists: Removal of the Zwitterionic Character with Piperidine Bioisosteres.

A known zwitterionic, heterocyclic P2Y14R antagonist 3a was substituted with diverse groups on the central phenyl and terminal piperidine moieties, following a computational selection process. The most potent analogues contained an uncharged piperidine bioisostere, prescreened in silico, while an aza-scan (central phenyl ring) reduced P2Y14R affinity. Piperidine amide 11, 3-aminopropynyl 19, and 5-(hydroxymethyl)isoxazol-3-yl) 29 congeners in the triazole series maintained moderate receptor affinity. Adaption of 5-(hydroxymethyl)isoxazol-3-yl gave the most potent naphthalene-containing (32; MRS4654; IC50, 15 nM) and less active phenylamide-containing (33) scaffolds. Thus, a zwitterion was nonessential for receptor binding, and molecular docking and dynamics probed the hydroxymethylisoxazole interaction with extracellular loops. Also, amidomethyl ester prodrugs were explored to reversibly block the conserved carboxylate group to provide neutral analogues, which were cleavable by liver esterase, and in vivo efficacy demonstrated. We have, in stages, converted zwitterionic antagonists into neutral molecules designed to produce potent P2Y14R antagonists for in vivo application.

Maxillomandibular advancement is a successful treatment for obstructive sleep apnoea: a systematic review and meta-analysis.

The primary objective of this review was to establish the effectiveness of maxillomandibular advancement (MMA) as a successful treatment modality in improving airway patency in patients with obstructive sleep apnoea (OSA). A systematic and detailed search was performed using PubMed Central, covering the period January 2000 to December 2015, with well-defined selection criteria. The authors independently conducted the study selection, data extraction, and assessed the risk of bias of the included studies. Twenty studies met the inclusion criteria. The outcome measures studied were the apnoea-hypopnoea index (AHI), respiratory disturbance index (RDI), Epworth Sleepiness Scale (ESS), lowest oxygen saturation (LSAT), and body mass index (BMI). The random-effects model was adopted for meta-analysis as moderate heterogeneity was identified. The analysis revealed significant changes in the outcome measures after the intervention. The results showed that the preoperative severity of OSA based on AHI and RDI significantly influences the outcome of MMA intervention, with a strong positive correlation between the pre MMA AHI values and the percentage change post intervention. The surgical success of MMA in patients with OSA was found to be 100% with respect to AHI and RDI scores. It is concluded that MMA is a successful treatment for OSA.

Two-stage opening of the Dover Strait and the origin of island Britain.

Late Quaternary separation of Britain from mainland Europe is considered to be a consequence of spillover of a large proglacial lake in the Southern North Sea basin. Lake spillover is inferred to have caused breaching of a rock ridge at the Dover Strait, although this hypothesis remains untested. Here we show that opening of the Strait involved at least two major episodes of erosion. Sub-bottom records reveal a remarkable set of sediment-infilled depressions that are deeply incised into bedrock that we interpret as giant plunge pools. These support a model of initial erosion of the Dover Strait by lake overspill, plunge pool erosion by waterfalls and subsequent dam breaching. Cross-cutting of these landforms by a prominent bedrock-eroded valley that is characterized by features associated with catastrophic flooding indicates final breaching of the Strait by high-magnitude flows. These events set-up conditions for island Britain during sea-level highstands and caused large-scale re-routing of NW European drainage.

Open-label phase 1b pilot study to assess the antiviral efficacy of simvastatin combined with sertraline in chronic hepatitis C patients.

BACKGROUND: 3-Hydroxy-3-methyl-glutaryl coenzyme A reductase inhibitors inhibit HCV replication in vitro. The combination of sertraline and simvastatin has synergistic antiviral activity in vitro, but there are no prior in vivo studies. Our aims were to prospectively assess the antiviral efficacy and safety of this drug combination in chronic hepatitis C (CHC) patients. METHODS: A total of 15 CHC adults (including 1 control subject) that were treatment-naive or prior partial responders/relapsers to standard-of-care therapy were enrolled at four centres (2 in Singapore and 2 in the US). Patients received simvastatin 40 mg once daily and sertraline 50 mg once daily for 7 days, and then 80 mg once daily and 100 mg once daily, respectively, for another 21 days with a 14-day follow-up. RESULTS: Of the 15 CHC patients, 13 completed the study. Subjects were mostly Caucasian (8/15), mean age 49.1 ±9 years and the genotype distribution was 1=10, 2=2 and 3=3. No subject discontinued dosing due to adverse events. Mean HCV RNA change from baseline was from -0.005 to -0.236 log(10) IU/ml across study intervals. Three subjects had transient >1 log(10) HCV RNA declines. No subject achieved >2 log(10) HCV RNA decline. CONCLUSIONS: The combination of sertraline and simvastatin is well-tolerated over the short-term, but has no significant antiviral or anti-inflammatory response in CHC patients. This may reflect in vivo differences in synergy between statin and/or selective serotonin reuptake inhibitors and incomplete inhibition of membrane protein prenylation with statin therapy.

A multi-variant, viral dynamic model of genotype 1 HCV to assess the in vivo evolution of protease-inhibitor resistant variants.

Variants resistant to compounds specifically targeting HCV are observed in clinical trials. A multi-variant viral dynamic model was developed to quantify the evolution and in vivo fitness of variants in subjects dosed with monotherapy of an HCV protease inhibitor, telaprevir. Variant fitness was estimated using a model in which variants were selected by competition for shared limited replication space. Fitness was represented in the absence of telaprevir by different variant production rate constants and in the presence of telaprevir by additional antiviral blockage by telaprevir. Model parameters, including rate constants for viral production, clearance, and effective telaprevir concentration, were estimated from 1) plasma HCV RNA levels of subjects before, during, and after dosing, 2) post-dosing prevalence of plasma variants from subjects, and 3) sensitivity of variants to telaprevir in the HCV replicon. The model provided a good fit to plasma HCV RNA levels observed both during and after telaprevir dosing, as well as to variant prevalence observed after telaprevir dosing. After an initial sharp decline in HCV RNA levels during dosing with telaprevir, HCV RNA levels increased in some subjects. The model predicted this increase to be caused by pre-existing variants with sufficient fitness to expand once available replication space increased due to rapid clearance of wild-type (WT) virus. The average replicative fitness estimates in the absence of telaprevir ranged from 1% to 68% of WT fitness. Compared to the relative fitness method, the in vivo estimates from the viral dynamic model corresponded more closely to in vitro replicon data, as well as to qualitative behaviors observed in both on-dosing and long-term post-dosing clinical data. The modeling fitness estimates were robust in sensitivity analyses in which the restoration dynamics of replication space and assumptions of HCV mutation rates were varied.

(S)-1-((S)-2-{[1-(4-amino-3-chloro-phenyl)-methanoyl]-amino}-3,3-dimethyl-butanoyl)-pyrrolidine-2-carboxylic acid ((2R,3S)-2-ethoxy-5-oxo-tetrahydro-furan-3-yl)-amide (VX-765), an orally available selective interleukin (IL)-converting enzyme/caspase-1 inhibitor, exhibits potent anti-inflammatory activities by inhibiting the release of IL-1beta and IL-18.

(S)-1-((S)-2-{[1-(4-amino-3-chloro-phenyl)-methanoyl]-amino}-3,3-dimethyl-butanoyl)-pyrrolidine-2-carboxylic acid ((2R,3S)-2-ethoxy-5-oxo-tetrahydro-furan-3-yl)-amide (VX-765) is an orally absorbed prodrug of (S)-3-({1-[(S)-1-((S)-2-{[1-(4-amino-3-chlorophenyl)-methanoyl]-amino}-3,3-dimethyl-butanoyl)-pyrrolidin-2yl]-methanoyl}-amino)-4-oxo-butyric acid (VRT-043198), a potent and selective inhibitor of interleukin-converting enzyme/caspase-1 subfamily caspases. VRT-043198 exhibits 100- to 10,000-fold selectivity against other caspase-3 and -6 to -9. The therapeutic potential of VX-765 was assessed by determining the effects of VRT-043198 on cytokine release by monocytes in vitro and of orally administered VX-765 in several animal models in vivo. In cultures of peripheral blood mononuclear cells and whole blood from healthy subjects stimulated with bacterial products, VRT-043198 inhibited the release of interleukin (IL)-1beta and IL-18, but it had little effect on the release of several other cytokines, including IL-1alpha, tumor necrosis factor-alpha, IL-6 and IL-8. In contrast, VRT-043198 had little or no demonstrable activity in cellular models of apoptosis, and it did not affect the proliferation of activated primary T cells or T-cell lines. VX-765 was efficiently converted to VRT-043198 when administered orally to mice, and it inhibited lipopolysaccharide-induced cytokine secretion. In addition, VX-765 reduced disease severity and the expression of inflammatory mediators in models of rheumatoid arthritis and skin inflammation. These data suggest that VX-765 is a novel cytokine inhibitor useful for treatment of inflammatory diseases.

Inactivation of caspase-1 in rodent brain: a novel anticonvulsive strategy.

PURPOSE: Cytokines and related inflammatory mediators are rapidly synthesized in the brain during seizures. We previously found that intracerebral administration of interleukin-1 (IL-1)-beta has proconvulsant effects, whereas its endogenous receptor antagonist (IL-1Ra) mediates potent anticonvulsant actions in various models of limbic seizures. In this study, we investigated whether seizures can be effectively inhibited by blocking the brain production of IL-1beta, by using selective inhibitors of interleukin-converting enzyme (ICE/caspase-1) or through caspase-1 gene deletion. METHODS: Caspase-1 was selectively blocked by using pralnacasan or VX-765. IL-1beta release was induced in mouse organotypic hippocampal slice cultures by proinflammatory stimuli [lipopolysaccharide (LPS) + adenosine triphosphate (ATP)] and measured with enzyme-linked immunosorbent assay (ELISA). IL-1beta production during seizures was measured in the rat hippocampus by Western blot. Seizures were induced in freely moving mice and rats by intrahippocampal injection of kainic acid and recorded by EEG analysis. RESULTS: Caspase-1 inhibition reduced the release of IL-1beta in organotypic slices exposed to LPS+ATP. Administration of pralnacasan (intracerebroventricular, 50 microg) or VX-765 (intraperitoneal, 25-200 mg/kg) to rats blocked seizure-induced production of IL-1beta in the hippocampus, and resulted in a twofold delay in seizure onset and 50% reduction in seizure duration. Mice with caspase-1 gene deletion showed a 70% reduction in seizures and an approximate fourfold delay in their onset. CONCLUSIONS: Inhibition of caspase-1 represents an effective and novel anticonvulsive strategy, which acts by selectively reducing the brain availability of IL-1beta.

Surgery alone or surgery with a combination radiation or chemoradiation for management of patients with bulky-stage IB2 cervical carcinoma.

The management of stage IB2 cervical carcinoma remains controversial. This retrospective review evaluates 47 IB2 cervical carcinoma patients treated with surgery alone (S), surgery plus postoperative radiotherapy (SR), or surgery plus postoperative chemoradiation (SRC). Median progression-free interval (PFI) was 70.3 months for the SR group (n= 21), 73.3 months for the SRC group (n= 15), and 33.5 months for the S group (n= 11). The survival rate was 76% for the SR group, 87% for the SRC group, and 55% for the S group. Overall 5-year survival rate for the three groups was 75%. Median follow-up for the patient population was 61.3 months. The number of the patient and the nonrandomized nature of this study preclude any definitive conclusions, but interestingly, the SRC and SR groups exhibited a substantially better PFI and overall survival compared to the S group. Selection bias does not appear to be a factor since patients in SR or SRC group were at greater risk for recurrence (eg, higher incidence of deep stromal invasion, parametrial involvement) than patients in the S group; yet, they still experienced superior PFI and overall survival. Further studies comparing postoperative irradiation and chemoradiation with these patients in a randomized phase 3 trial may be warranted.

IL-converting enzyme/caspase-1 inhibitor VX-765 blocks the hypersensitive response to an inflammatory stimulus in monocytes from familial cold autoinflammatory syndrome patients.

Familial cold autoinflammatory syndrome (FCAS) and the related autoinflammatory disorders, Muckle-Wells syndrome and neonatal onset multisystem inflammatory disease, are characterized by mutations in the CIAS1 gene that encodes cryopyrin, an adaptor protein involved in activation of IL-converting enzyme/caspase-1. Mutations in cryopyrin are hypothesized to result in abnormal secretion of caspase-1-dependent proinflammatory cytokines, IL-1beta and IL-18. In this study, we examined cytokine secretion in PBMCs from FCAS patients and found a marked hyperresponsiveness of both IL-1beta and IL-18 secretion to LPS stimulation, but no evidence of increased basal secretion of these cytokines, or alterations in basal or stimulated pro-IL-1beta levels. VX-765, an orally active IL-converting enzyme/caspase-1 inhibitor, blocked IL-1beta secretion with equal potency in LPS-stimulated cells from FCAS and control subjects. These results further link mutations in cryopyrin with abnormal caspase-1 activation, and support the clinical testing of caspase-1 inhibitors such as VX-765 in autoinflammatory disorders.

The α1,α2, and α3 Subunits of GABAA Receptors: Comparison in Seizure-Prone and -Resistant Mice and during Development.

Gamma-aminobutyric acid (GABA), the major inhibitory neurotransmitter in brain, opens chloride channels through actions on GABAA receptors. We now report base and amino acid sequences of the α1, α2, and α3 subunits from GABAA receptors of audiogenic seizure-prone (DBA/2J) and -resistant (C57BL/6J) inbred strains of mice. Inbreeding had fixed different alleles of the α1 subunit in the two strains, giving five base differences in the cDNAs. None of these affected amino acid sequence, but one did create a NsiI restriction site potentially useful in mapping genomic DNA. No base or amino acid sequence differences between the strains were detected for the other two subunits. Northern blots revealed no apparent strain differences in message levels for these three subunits in whole brains of the mice at 3 weeks of age, the peak of seizure susceptibility in DBA/2J, but did reveal distinct regional and developmental patterns of expression among the subunits in mouse brain.