Metal Cross-Linked Supramolecular Gel Noodles: Structural Insights and Antibacterial Assessment.

Achieving precise control over gelator alignment and morphology is crucial for crafting tailored materials and supramolecular structures with distinct properties. We successfully aligned the self-assembled micelles formed by a functionalized dipeptide 2NapFF into long 1-D "gel noodles" by cross-linking with divalent metal chlorides. We identify the most effective cross-linker for alignment, enhancing mechanical stability, and imparting functional properties. Our study shows that Group 2 metal ions are particularly suited for creating mechanically robust yet flexible gel noodles because of their ionic and nondirectional bonding with carboxylate groups. In contrast, the covalent nature and high directional bonds of d-block metal ions with carboxylates tend to disrupt the self-assembly of 2NapFF. Furthermore, the 2NapFF-Cu noodles demonstrated selective antibacterial activity, indicating that the potent antibacterial property of the copper(II) ion is preserved within the cross-linked system. By merging insights into molecular alignment, gel extrusion processing, and integrating specific functionalities, we illustrate how the versatility of dipeptide-based gels can be utilized in creating next-generation soft materials.

Trp-Trp acts as a multifunctional blocker for human bitter taste receptors, hTAS2R14, hTAS2R16, hTAS2R43, and hTAS2R46.

Many functional food ingredients activate human bitter taste receptors (hTAS2Rs). In this study, A novel inhibitor, Trp-Trp, for hTAS2R14 was identified by searching for the agonist peptide's analogs. Trp-Trp also inhibited hTAS2R16, hTAS2R43, and hTAS2R46, which share the same agonists with hTAS2R14. The multifunctional characteristic of Trp-Trp is advantageous for use as bitterness-masking agents in functional foods.

Synthesis and Penicillin-binding Protein Inhibitory Assessment of Dipeptidic 4-Phenyl-ß-lactams from α-Amino Acid-derived Imines.

Monocyclic ß-lactams revive the research field on antibiotics, which are threatened by the emergence of resistant bacteria. A six-step synthetic route was developed, providing easy access to new 3-amino-1-carboxymethyl-4-phenyl-ß-lactams, of which the penicillin-binding protein (PBP) inhibitory potency was demonstrated biochemically.

Design, synthesis, and functional assessment of Cmpd-15 derivatives as negative allosteric modulators for the ß2-adrenergic receptor.

The ß2-adrenergic receptor (ß2AR), a G protein-coupled receptor, is an important therapeutic target. We recently described Cmpd-15, the first small molecule negative allosteric modulator (NAM) for the ß2AR. Herein we report in details the design, synthesis and structure-activity relationships (SAR) of seven Cmpd-15 derivatives. Furthermore, we provide in a dose-response paradigm, the details of the effects of these derivatives in modulating agonist-induced ß2AR activities (G-protein-mediated cAMP production and ß-arrestin recruitment to the receptor) as well as the binding affinity of an orthosteric agonist in radio-ligand competition binding assay. Our results show that some modifications, including removal of the formamide group in the para-formamido phenylalanine region and bromine in the meta-bromobenzyl methylbenzamide region caused dramatic reduction in the functional activity of Cmpd-15. These SAR results provide valuable insights into the mechanism of action of the NAM Cmpd-15 as well as the basis for future development of more potent and selective modulators for the ß2AR based on the chemical scaffold of Cmpd-15.

Health-related quality-of-life implications of cardiovascular events in individuals with type 2 diabetes mellitus: A subanalysis from the Saxagliptin Assessment of Vascular Outcomes Recorded in Patients with Diabetes Mellitus (SAVOR)-TIMI 53 trial.

BACKGROUND: The impact of cardiovascular complications on health-related quality-of-life (HRQoL) in type 2 diabetes mellitus has not been clearly established. Using EQ5D utility data from SAVOR-TIMI 53, a large phase IV trial of saxagliptin versus placebo, we quantified the impact of cardiovascular and other major events on HRQoL. METHODS: EQ5D utilities were recorded annually and following myocardial infarction (MI) or stroke. Utilities among patients experiencing major cardiovascular events were analyzed using linear mixed-effects regression, adjusting for baseline characteristics (including EQ5D utility), and compared to those not experiencing major cardiovascular events. Mean utility decrements with standard errors (SE) were estimated as the difference in utility before and after the event. FINDINGS: The mean EQ5D utility of the sample was 0.776 at all time points, and did not differ by treatment. However, mean baseline and month 12 utilities among those with a major cardiovascular event were 0.751 and 0.714. Mean utilities were 0.691 within 3months of, 0.691 3-6months after, and 0.714 6-12months after, a major cardiovascular event. Cardiovascular event-specific utility decrements were 0.05 (0.007) for major cardiovascular events over the same time periods. Decrements of 0.051 (0.012; myocardial infarction), 0.111 (0.022; stroke), 0.065 (0.014; hospitalization for heart failure) 0.019 (0.024; hospitalization for hypoglycemia) were estimated; all coefficients were statistically significant. INTERPRETATION: Consistent with clinical outcomes reported elsewhere, saxagliptin did not improve HRQoL. Cardiovascular complications were associated with significantly decreased HRQoL, most substantial earlier after the event. FUNDING: BMS/AZ.

Effects of a caspase and a calpain inhibitor on resting energy expenditures in normal and hypermetabolic rats: a pilot study.

Several diseases induce hypermetabolism, which is characterized by increases in resting energy expenditures (REE) and whole body protein loss. Exaggerated protein degradation is thought to be the driving force underlying this response. The effects of caspase and calpain inhibitors on REE in physiological and hypermetabolic conditions, however, are unknown. Thus, we studied whether MDL28170 (calpain inhibitor) or z-VAD-fmk (caspase inhibitor) affect REE under physiological conditions and during hypermetabolism post-burn. Rats were treated five times weekly and observed for 6 weeks. Treatment was started 2 h (early) or 48 h (late) after burn. In normal rats, MDL28170 transiently increased REE to 130 % of normal during week 2-4. z-VAD-fmk reduced REE by 20-25 % throughout the observation period. Within 14 days after burns, REE increased to 130+/-5 %. Whereas MDL28170/early treatment did not affect REE, MDL28170/late transiently increased REE to 180+/-10 % of normal by week 4 post-burn. In contrast, with z-VAD-fmk/early REE remained between 90-110 % of normal post-burn. z-VAD-fmk/late did not affect burn-induced increases in REE. These data suggest that caspase cascades contribute to the development of hypermetabolism and that burn-induced hypermetabolism can be pharmacologically modulated. Our data point towards caspase cascades as possible therapeutic targets to attenuate hypermetabolism after burns, and possibly in other catabolic disease processes.

An in vivo and in vitro assessment of the anti-inflammatory, antinociceptive, and immunomodulatory activities of Clematis terniflora DC. extract, participation of aurantiamide acetate.

AIM: Clematis terniflora DC. has been widely used as a traditional Chinese medicine for the treatment of tonsillitis, rheumatoid arthritis, and prostatitis. Despite its widespread use in China, there are currently no studies systematically examined its therapeutic effects and mechanism of action. As such, the present study was conducted to evaluate the anti-inflammatory, antinociceptive, and immunomodulatory effects of C. terniflora DC. using rodent and cellular models. METHODS: The anti-inflammatory properties of the 70% ethanol eluted fraction of the 70% ethanol extract of C. terniflora DC. (EECTD) were evaluated using the xylene-induced ear swelling test, the carrageenan-induced edema model, and the cotton pellet granuloma method. Its antinociceptive activities were determined using both the acetic acid-induced writhing test and the hot plate assay. In parallel, we conducted an in vitro assay in LPS-induced RAW264.7 cells to examine the anti-inflammatory effects of EECTD and its purified form, aurantiamide acetate (AA) on inhibition of nitric oxide (NO) and prostaglandin E2 (PGE2) release. RESULTS: EECTD (300mg/kg) significantly reduced the number of writhing, extended the pain response latency, and suppressed xylene-induced ear swelling. Each EECTD treatment group also had significant inhibition of cotton granulation formation in addition to reduced carrageenan-induced paw edema. EECTD was also shown to alleviate signs of inflammation in histopathological paw sections. However, it had a less noticeable effect on mouse ear swelling in the delayed type hypersensitivity test. A purified compound was isolated from EECTD and its structure was identified as AA. In vitro experimental results showed that both EECTD and AA were able to significantly inhibit the release of pro-inflammatory cytokines NO and PGE2 on LPS-induced RAW264.7 cells. CONCLUSION: These results suggest that EECTD has significant anti-inflammatory and antinociceptive activities, partially related to one of the active substances identified as AA. We hypothesize that these effects are related to its ability to inhibit the production of cytokines NO and PGE2. However, further work will be needed to determine its exact mechanism of action.

Population pharmacokinetic-pharmacodynamic modelling and simulation of neutropenia induced by TP300, a novel topoisomerase I inhibitor.

OBJECTIVES: TP300 is a novel topoisomerase I inhibitor with neutropenia as a significant toxicity. We developed and evaluated a pharmacokinetic-pharmacodynamic (PK-PD) model, using data from Phase I and II trials to predict neutrophil decrease in patients treated with TP300. METHODS: Plasma drug concentrations of TP300, its active form TP3076 and active metabolite TP3011 and absolute neutrophil counts (ANCs) from a Phase I trial were analysed as a training dataset. A two-plus-two-compartment model was applied to the pharmacokinetics of TP3076 and TP3011. A semi-mechanistic model was used to describe the PK-PD relationship between the plasma concentration of TP3076 and TP3011, and changes in ANC. KEY FINDINGS: The model fitted well to plasma concentrations of TP3076 and TP3011. Model appropriateness was confirmed in a Phase II trial validation dataset. Body weight and liver biochemistry values were identified as covariates. A semi-mechanistic PK-PD model was applied and the longitudinal decrease in ANC was simulated. Neutrophil counts reached their nadir approximately 2 weeks after administration of TP300, and the proportion of subjects affected increased with dose. CONCLUSIONS: This PK-PD model to predict neutropenia following treatment with TP300 fitted well the decrease in ANC with total concentration of TP3076 and TP3011.

Central synapses release a resource-efficient amount of glutamate.

Why synapses release a certain amount of neurotransmitter is poorly understood. We combined patch-clamp electrophysiology with computer simulations to estimate how much glutamate is discharged at two distinct central synapses of the rat. We found that, regardless of some uncertainty over synaptic microenvironment, synapses generate the maximal current per released glutamate molecule while maximizing signal information content. Our result suggests that synapses operate on a principle of resource optimization.

New ketomethylene inhibitor analogues: synthesis and assessment of structural determinants for N-domain selective inhibition of angiotensin-converting enzyme.

Angiotensin-converting enzyme (ACE) is a zinc metallopeptidase containing two homologous domains. While the C-domain plays a major role in blood pressure regulation, the N-domain hydrolyzes the antifibrotic agent N-acetyl-Ser-Asp-Lys-Pro. Thus, N-domain selective (N-selective) inhibitors could be useful in the treatment of conditions relating to excessive tissue fibrosis. New keto-ACE analogues were designed that contained functionalities considered important for N-selective inhibitor RXP407 binding, namely, a P(2) Asp, N-acetyl group, and C-terminal amide. Such functionalities were incorporated to assess the structural determinants for N-selective binding in a novel inhibitor template. Inhibitors containing a C-terminal amide and modified P(2)' group were poor inhibitors of the N-domain, with several of these displaying improved inhibition of the C-domain. Molecules with both a C-terminal amide and P(2) Asp were also poor inhibitors and not N-selective. Compounds containing a free C-terminus, a P(2) Asp and protecting group displayed a change of more than 1000-fold N-selectivity compared with the parent molecule. Molecular docking models revealed interaction of these P(2) groups with S(2) residues Tyr369 and Arg381. This study emphasizes the importance of P(2) functionalities in allowing for improved N-selective binding and provides further rationale for the design of N-selective inhibitors, which could be useful in treating tissue fibrosis.

The role of RamA on the development of ciprofloxacin resistance in Salmonella enterica serovar Typhimurium.

Active efflux pump is a primary fluoroquinolone resistant mechanism of clinical isolates of Salmonella enterica serovar Typhimurium. RamA is an essential element in producing multidrug resistant (MDR) S. enterica serovar Typhimurium. The aim of the present study was to elucidate the roles of RamA on the development of ciprofloxacin, the first choice for the treatment of salmonellosis, resistance in S. enterica serovar Typhimurium. Spontaneous mutants were selected via several passages of S. enterica serovar Typhimurium CVCC541 susceptible strain (ST) on M-H agar with increasing concentrations of ciprofloxacin (CIP). Accumulation of ciprofloxacin was tested by the modified fluorometric method. The expression levels of MDR efflux pumps were determined by real time RT-PCR. In ST and its spontaneous mutants, the ramA gene was inactivated by insertion of the kan gene and compensated on a recombinant plasmid pGEXΦ(gst-ramA). The mutant prevention concentration (MPC) and mutant frequencies of ciprofloxacin against ST and a spontaneous mutant in the presence, absence and overexpression of RamA were tested. Four spontaneous mutants (SI1-SI4) were obtained. The SI1 (CIP MICs, 0.1 mg/L) without any target site mutation in its quinolone resistant determining regions (QRDRs) and SI3 (CIP MICs, 16 mg/L) harboring the Ser83→Phe mutation in its QRDR of GyrA strains exhibited reduced susceptibility and resistance to multidrugs, respectively. In SI1, RamA was the main factor that controlled the susceptibility to ciprofloxacin by activating MdtK as well as increasing the expression level of acrAB. In SI3, RamA played predominant role in ciprofloxacin resistance via increasing the expression level of acrAB. Likewise, the deficiency of RamA decreased the MPCs and mutant frequencies of ST and SI2 to ciprofloxacin. In conclusion, the expression of RamA promoted the development of ciprofloxacin resistant mutants of S. enterica serovar Typhimurium. The inhibition of RamA could decrease the appearance of the ciprofloxacin resistant mutants.

Human bitter taste receptors hTAS2R8 and hTAS2R39 with differential functions to recognize bitter peptides.

The strong bitter peptide, Phe-Phe-Pro-Arg, activated cultured cells expressing either of the known human bitter taste receptors, hTAS2R8 and hTAS2R39. The partial structure of Pro-Arg activated hTAS2R39, but did not activate hTAS2R8. These receptors may not indiscriminately recognize bitter peptides, but have a differential function in their recognition.

Calcitonin gene-related peptide receptor antagonists for the treatment of migraine: a patent review.

BACKGROUND: Migraine is a debilitating headache disorder which affects approximately 12% of the general population and is the cause of significant loss of productivity (i.e., lost time from work or school) for those afflicted. The current standard of care, the 5-HT(1B/1D) agonists known as triptans, is contraindicated in patients with cardiovascular disease due to their inherent vasoconstrictive activity; thus, there is a need to develop an alternative therapy for the treatment of the disorder. OBJECTIVE: This article reviews patent publications related to the use of small molecule calcitonin gene-related peptide (CGRP) receptor antagonists for the treatment of migraine that have appeared in the literature within the past decade. The commentary is supplemented by information presented in journal articles and focuses on the activity of several major pharmaceutical companies in the field. CONCLUSION: Two small molecule CGRP receptor antagonists, olcegepant and telcagepant, have been shown to be clinically efficacious in the treatment of migraine, and thus provide validation of this novel therapeutic mechanism.

pH-Dependent inhibition of the human bitter taste receptor hTAS2R16 by a variety of acidic substances.

Some acidic peptides are known to reduce bitterness, but the detailed mechanism underlying this effect remains to be elucidated. In this study, we analyzed the effects of acidic dipeptides on the inhibition of the human bitter taste receptor hTAS2R16. Calcium imaging analysis of HEK293T cells expressing hTAS2R16 revealed that their response to the bitter tastant salicin was reduced in the presence of acidic dipeptides. A similar inhibitory effect was observed in a variety of other acids. The inhibition depended on the pH values resulting from the addition of acids but not on their concentrations. Our results suggest that the inhibition of the bitter taste receptors can be attributed to the bitterness-masking effect of the acidic dipeptides and that acidic pH may be one of the critical factors responsible for this sensory event.

Electric fields due to synaptic currents sharpen excitatory transmission.

The synaptic response waveform, which determines signal integration properties in the brain, depends on the spatiotemporal profile of neurotransmitter in the synaptic cleft. Here, we show that electrophoretic interactions between AMPA receptor-mediated excitatory currents and negatively charged glutamate molecules accelerate the clearance of glutamate from the synaptic cleft, speeding up synaptic responses. This phenomenon is reversed upon depolarization and diminished when intracleft electric fields are weakened through a decrease in the AMPA receptor density. In contrast, the kinetics of receptor-mediated currents evoked by direct application of glutamate are voltage-independent, as are synaptic currents mediated by the electrically neutral neurotransmitter GABA. Voltage-dependent temporal tuning of excitatory synaptic responses may thus contribute to signal integration in neural circuits.

Reduction of Abeta levels in the Sprague Dawley rat after oral administration of the functional gamma-secretase inhibitor, DAPT: a novel non-transgenic model for Abeta production inhibitors.

Considerable effort has been made to develop drugs that delay or prevent neurodegeneration. These include inhibitors of Abeta-generating proteases for the treatment of Alzheimer's disease. Testing the amyloid hypothesis in vivo requires molecules that are capable of entering the CNS and that produce a substantial reduction in brain Abeta levels. Plaque-developing APP transgenic mice are currently widely used as an in vivo model of choice as these animals produce readily measurable amounts of human Abeta. They are very useful in the testing of a variety of amyloid-lowering approaches but their use for compound screening is often limited by their cost. Transgenic animals also require extensive, time-consuming breeding programs and can show high inter-animal differences in the expression level of the transgene. Hence, we considered it important to develop and characterize a new and simple non-transgenic animal model for testing Abeta modulation. For this purpose, Wild-type adult Sprague Dawley rats were treated with DAPT, a functional gamma-secretase inhibitor, and the Abeta40 and Abeta42 levels in brain-tissue and body fluids were assessed. We showed that DAPT, given orally, significantly lowered Abeta40 and Abeta42 peptide levels in brain extract, CSF, and the plasma dose- and time-dependently. We can conclude that our data establish the usefulness of the wild-type rat model for testing small-molecule inhibitors of Abeta production.

Resistance pattern and assessment of phenicol agents' minimum inhibitory concentration in multiple drug resistant Chryseobacterium isolates from fish and aquatic habitats.

AIMS: To assess the susceptibility of Chryseobacterium isolates of fish and aquatic habitats to antimicrobial compounds. Special attention was paid to the resistance to chloramphenicol and florfenicol, a phenicol derivative recently licensed for use in veterinary medicine and fish farming. METHODS AND RESULTS: Sixty-seven Chryseobacterium spp. isolates and reference strains, originating mainly from different aquatic habitats, were tested using the disk-diffusion method. In addition, agar dilution was used for assessing minimum inhibitory concentration of chloramphenicol and florfenicol. In spite of (i) conditions that hampered properly standardized experiments and (ii) the heterogeneity of the isolates resulting in some aberrant values in diffusion, correlation between the two methods was confirmed. Most of the isolates exhibited considerable multiresistance to most antimicrobial drug families, and many were clearly resistant to phenicols. Molecular investigations conducted on 10 strains selected for high resistance to florfenicol did not establish the existence of floR or cmlA genes currently reported in the literature as responsible for florfenicol resistance. Nevertheless, when an efflux pump inhibitor, phenyl-arginin-beta-naphthylamide, was combined with diffusion tests, drug susceptibility to florfenicol was restored, suggesting that Chryseobacterium's resistance to this molecule is under the control of efflux mechanisms. CONCLUSIONS: Constitutive multiresistance to antibiotics is common in chryseobacteria isolated from the aquatic environment. Although no gene related to the floR family could be detected, efflux mechanisms could partly support the resistance to phenicols. SIGNIFICANCE AND IMPACT OF THE STUDY: These results explain the difficulty of treatment and clearly reflect the properties previously reported in Chryseobacterium isolates of human origin. Because several species have been involved in opportunistic infections in humans, the possible role of aquatic organisms as a source of infection should be considered.

Assessment of substitution in the second pharmacophore of Dmt-Tic analogues.

The Dmt-Tic pharmacophore exhibits potent delta-opioid receptor antagonism. Analogues with substitutions in the second pharmacophore with (1, 1') or without a COOH function (2-9) were synthesized: several had high delta affinity (1', 2, 7, and 9), but exhibited low to non-selectivity toward mu receptors similar to H-Dmt-Tic-amide and H-Dmt-Tic-ol. Functional bioactivity indicated high delta antagonism (pA2 7.4-7.9) (1', 2, and 9) and modest mu agonism, pEC50 (6.1-6.3) (1', 2, 8, and 9), but with Emax values analogous to dermorphin. These Dmt-Tic analogues with mixed delta antagonist/mu agonist properties would appear to be better candidates as analgesics than pure mu agonists.

Glutamine peptide-supplemented long-term total parenteral nutrition: effects on intracellular and extracellular amino acid patterns, nitrogen economy, and tissue morphology in growing rats.

Glutamine (GLN) is a nonessential amino acid that is not included in current regimens for parenteral nutrition because of its chemical instability. This study tested the hypothesis that GLN supplementation during long-term total parenteral nutrition (TPN) (3 weeks) would enhance GLN availability, thereby improving nitrogen economy and growth in a growing rat model: Standard TPN delivering 300 kcal/kg per day (lipid:carbohydrate = 1.1) including 2.1 g of nitrogen per kilogram per day in an all-in-one solution was compared with an isonitrogenous, isocaloric, and isovolemic TPN regimen with 0.29 g of nitrogen per kilogram per day substituted by GLN derived from the dipeptides glycyl-GLN and alanyl-GLN (TPN GLN). Enterally fed controls were included. Analysis was confined to nonbacteremic animals with negative blood culture, in which extracellular and intracellular amino acid concentrations including GLN, nitrogen balance, serum protein concentrations, growth, and histologic sections of liver and small-bowel mucosa (light and scanning electron microscopy) were evaluated. Hepatic intracellular GLN concentrations were significantly lower, in animals receiving GLN-free TPN (11.7 +/- 1.6 nmol/mg fat-free dry and solid tissue mass, n = 9) compared with both GLN-supplemented TPN (16.0 +/- 3.0, n = 7) and enteral feeding (18.2 +/- 1.8, n = 6) (p < .001). Corresponding results were found for intracellular GLN concentrations in skeletal muscle (TPN standard 12.5 +/- 3.1, TPN GLN 14.7 +/- 3.1, enteral control 17.3 +/- 2.3, p < .05), intestinal mucosa, and spleen as well as for plasma concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)