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Linear polyethylenimine (L-PEI) has numerous applications, such as in pharmaceutical formulations, gene delivery, and water treatment. However, due to the presence of secondary amine groups, L-PEI shows a relatively high toxicity and low biocompatibility. Here, various organic anhydrides were used to modify L-PEI to reduce its toxicity and enhance its functionality. We selected methacrylic anhydride, crotonic anhydride, maleic anhydride, and succinic anhydride to modify L-PEI. The structure of the resulting derivatives was characterized using 1H NMR and FTIR spectroscopies, and their behavior in aqueous solutions was studied using turbidimetric and electrophoretic mobility measurements over a broad range of pHs. A fluorescence flow through method determined the mucoadhesive properties of the polymers to the bovine palpebral conjunctiva. Methacrylated L-PEI and crotonylated L-PEI showed strong mucoadhesive properties at pH 7.4, likely due to covalent bonding with mucin thiol groups. In contrast, maleylated and succinylated L-PEI were poorly mucoadhesive as the pH was above their isoelectric point, resulting in electrostatic repulsion between the polymers and mucin. The toxicity of these polymers was evaluated using in vivo assays with planaria and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) cell viability assay in human alveolar epithelial cells. Moreover, the irritancy of polymers was assessed using a slug mucosa irritation assay. The results demonstrated that anhydride modification mitigated the adverse toxicity effects seen for parent L-PEI.

Herein, we sequenced and assembled the genome of a Shigella sonneiisolate carrying several small plasmids using a hybrid approach that combined Oxford Nanopore Technologies and Illumina platforms.

: Carbapenemase-producing Enterobacterales (CPE) represent a public health concern. The limited antimicrobial options against CPE have led to the development of novel antimicrobial molecules. In the present study, we characterized the genetic determinants associated with the resistance to ceftazidime/avibactam (CAZ-AVI), meropenem/vaborbactam (MER-VAB), imipenem/relebactam (IMI-REL) and cefiderocol (CFD) in a carbapenemase-producing Klebsiella pneumoniaestrain isolated from a critically ill patient.

PARs (protease-activated receptors) are a family of four G-protein-coupled receptors for proteases from the circulation, inflammatory cells and epithelial tissues. This report focuses on PAR2, which plays an important role in inflammation and pain. Pancreatic (trypsin I and II) and extrapancreatic (trypsin IV) trypsins, mast cell tryptase and coagulation factors VIIa and Xa cleave and activate PAR2. Proteases cleave PAR2 to expose a tethered ligand that binds to the cleaved receptor. Despite this irreversible activation, PAR2 signalling is attenuated by β-arrestin-mediated desensitization and endocytosis, and by lysosomal targeting and degradation, which requires ubiquitination of PAR2. β-Arrestins also act as scaffolds for the assembly of multi-protein signalling complexes that determine the location and function of activated mitogen-activated protein kinases. Observations of PAR2-deficient mice support a role for PAR2 in inflammation, and many of the effects of PAR2 activators promote inflammation. Inflammation is mediated in part by activation of PAR2 in the peripheral nervous system, which results in neurogenic inflammation and hyperalgesia.

The trigeminovascular system is considered to play a role in the mechanism of migraine headache. Novel in vitro animal models that investigate the release of neuropeptides may be of help to understand the pathophysiology and pharmacology of trigeminal neurons. Here, we examined the release of the immunoreactivity (LI) of the sensory neuropeptides calcitonin gene-related peptide (CGRP) and substance P (SP) from slices of rat and guinea pig trigeminal ganglia with proximal nerve trunks attached. Electrical field stimulation (EFS, 10 Hz), high K+medium (50 mM) and capsaicin (1 μM) caused a significant increase in CGRP-LI outflow. SP-LI was also released after exposure to EFS, high K+and capsaicin. The increase in CGRP-LI outflow induced by EFS was markedly reduced in a Ca2+-free medium and by pretreatement with a high capsaicin concentration, tetrodotoxin, ω-conotoxin, dihydroergotamine and sumatriptan. Sensory neuropeptide release from slices of rat trigeminal ganglia with nerve trunks attached fulfills the criteria required to define it as a neurosecretory event. This is a novel method for studying trigeminal neuron pathophysiology and the action of antimigraine drugs.

The role of the amino acids contained in the sequence of HOE 140 (H-DArg-Arg-Pro-Hyp-Gly-Thi-Ser-DTic-Oic-Arg-OH), a potent and selective bradykinin B 2 receptor peptide antagonist, has been investigated by the replacement of each original residue (one by one) with Ala. The resulting set of decapeptides has been tested for the B 2 antagonist activity as well as for competition with the binding of [ 3 H]BK to plasma membranes of the human umbilical vein (hUV). Positive correlations have been established between data obtained with the bioassay and with the binding in the hUV (same species, same tissue) and also between the two bioassays, the guinea-pig ileum (GPI) and the hUV (different species, different tissue). The structure-activity study has shown that the replacement of any of the residues that constitute HOE 140 with Ala is accompanied by a decrease of potency of at least 1 log unit. The analogues can be divided into three groups, with Ala and Ala showing affinities lower than HOE 140 by a factor of 10, Ala and Ala by a factor of 100 and Ala, Ala, Ala, Ala and Ala by a factor higher than 100 (100-1000). To verify the effect of chirality, the DAla and DSer analogues were synthesized and it was found that the substitution with a D-residue in position 5 is not tolerated while that in position 7 is favourable. The DSer derivative is the most potent analogue found in this study: it shows potency as high as that of HOE 140 in the bioassays.

The tachykinin, neurokinin A (NKA), contracts guinea‐pig airways both in vitroand in vivo, preferentially activating smooth muscle NK2receptors, although smooth muscle NK1receptors may also contribute. In vitroevidence suggests that NKA activates epithelial NK1receptors, inducing the release of nitric oxide (NO) and subsequent smooth muscle relaxation. A number of selective NK1receptor agonists have been reported to activate both smooth muscle and epithelial NK1receptors, however septide appears only to activate smooth muscle NK1receptors.The aim of the present study was to investigate whether NKA‐induced bronchoconstriction in guinea‐pigs in vivomay be limited by NO release viaNK1receptor activation, and whether selective NK1receptor agonists may activate this mechanism differently.Aerosolized NKA caused an increase in total pulmonary resistance (RL) that was markedly reduced by the NK2receptor antagonist, SR 48968, and abolished by the combination of SR 48968 and the NK1receptor antagonist, CP‐99,994. The increase in RL evoked by NKA was potentiated by pretreatment with the NO synthase (NOs) inhibitor, L‐NAME, but not by the inactive enantiomer D‐NAME. Potentiation by L‐NAME of NKA‐induced increase in RL was reversed by L‐Arginine, but not by D‐Arginine.Pretreatment with L‐NAME did not affect the increase in RL induced by the selective NK2receptor agonist, [β‐Ala8]NKA(4‐10), and by the selective NK1receptor agonist, septide, whereas it markedly potentiated the increase in RL caused by a different NK1selective agonist, [Sar9,Met(O2)11]SP. Dose‐response curves showed that septide was a more potent bronchoconstrictor than [Sar9,Met(O2)11]SP to cause bronchoconstriction.Pretreatment with the NK1receptor antagonist, CP‐96,994, abolished the ability of L‐NAME to increase bronchoconstriction to aerosolized NKA. Bronchoconstriction to aerosolized NKA was increased by L‐NAME, after pretreatment with the NK3receptor antagonist, SR 142801.The present study shows that in vivobronchoconstriction in response to the aerosolized naturally occurring tachykinin, NKA, is limited by its own ability to release relaxant NO viaNK1receptor activation. This receptor is apparently insensitive to septide, thus justifying, at least in part, the high potency of septide to cause bronchoconstriction in guinea‐pigs.

Motor responses to des‐Arg9‐bradykinin and bradykinin were studied in the isolated mouse trachea (precontracted with carbachol, 10 μM) and the urinary bladder of either Swiss, C57Bl/6J or bradykinin B2receptor knockout (Bk2r−/−) mice after 1–6 h in vitro. The expression of mRNA for the mouse B1receptor in tracheal and urinary bladder tissues was also studied by using Northern blot analysis.In isolated tracheae, des‐Arg9‐bradykinin produced a relaxant response that increased over time: no response was observed after 1 h of incubation, whereas after 6 h the maximum response (1 μM) was 68–84% of the relaxation produced by isoproterenol (1 μM) in the three mouse strains. The relaxant response to bradykinin (1 μM) observed at 1 h (38–51% of isoproterenol) was increased (62–65% of isoproterenol) after 6 h in Swiss and C57Bl/6J mice, but was absent in Bk2r−/−mice. In the presence of cycloheximide, des‐Arg9‐bradykinin did not cause any response at 6 h.Similar findings were obtained in the urinary bladder: at 1 h des‐Arg9‐bradykinin (1 μM) did not cause any motor effect, whereas at 6 h it caused a contraction that was 28–59% of that produced by carbachol (1 μM) in the three mouse strains. Cycloheximide blocked the response to des‐Arg9‐bradykinin. Bradykinin (1 μM) contracted urinary bladders at 1 h (34–35% of carbachol), as well as at 6 h (66–77% of carbachol) in Swiss and C57Bl/6J strains, but was without effect in Bk2r−/−mice.Northern blot hybridization with a specific cDNA probe against mouse B1receptor mRNA using total RNA extracted from tracheae and urinary bladders freshly removed from Swiss and Bk2r−/−mice revealed minimal expression. However, marked hybridization was detected 150 min after in vitroexposure in both tissues.Evidence is provided that in vitroexposure of mouse trachea and urinary bladder causes a time‐dependent induction of B1receptors that cause relaxation and contraction, respectively.

Using models of airway diseases, our understanding of the role of tachykinins and kinins in airway pathophysiology has been greatly enhanced by the recent development of a large series of peptide, peptoid and non-peptide antagonists for tachykinin and kinin receptors. This article reviews the experimental findings of the contribution of kinins and tachykinins and their respective receptors, in models of airway inflammation in response to agents known to trigger or worsen asthma attacks, such as antigen and cold air. Some new antagonists, mostly of a non-peptide nature, exhibit excellent pharmacodynamic and pharmacokinetic profiles; a brief account of early clinical studies in which they have been used is also given.

Abstract. FR 190997, a new kinin B₂ receptor agonist of non-peptide nature, has been studied in three isolated vessels: the human umbilical vein (hUV), the rabbit jugular vein (rbJV), and the pig coronary artery (pCA). Bradykinin (BK) contracts the hUV and rbJV through smooth muscle B₂ receptors, while it relaxes the pCA through endothelial receptors of the B₂ type. Contractions of the hUV and rbJV in response to FR 190997 show slow onset and are not reproducible compared to the rapid and reproducible effect of BK. They reach only 70% and 30% of the BK-induced maximal contractions in the hUV and rbJV, respectively. The effects of FR 190997 are antagonised by HOE 140 and this antagonist shows similar pK_B values against BK and FR 190997, indicating that the non-peptide agent interacts with the kinin B₂ receptor. FR 190997 is inactive as relaxant of the pCA; in this tissue, it acts as a pure and competitive antagonist, with a pK_B value of 7.6, while HOE 140 acts as an insurmountable antagonist (pK_B 9.3). When tested as an antagonist, FR 190997 inhibits also the contractile effects of BK in the hUV (pK_B 7.8) and in the rbJV (pK_B 7.6). FR 190997 is selective for the B₂ receptor since it does not interact with the B₁, and is specific since it does not affect the contraction evoked by 5-hydroxytryptamine, endotelin-1, and noradrenaline in the hUV, or the relaxation induced by substance P in the pCA. FR 190997 shows therefore different pharmacological profiles in various preparations, acting as a partial agonist in the hUV and especially in the rbJV and as a pure antagonist in the pCA. This new compound could be of interest in understanding how non-peptide agonists may activate receptors for peptides.

Abstract: The coronary artery and renal vein of the adult pig are sensitive and reliable monoreceptor systems for studying kinin receptors. The pig coronary artery with intact endothelium is highly sensitive to bradykinin (BK, pEC50 8.6), while being insensitive to the B1 receptor agonist, LysdesArg9BK. The tissue responds to BK with concentration-dependent relaxation, which is prevented by B2 receptor antagonists, particularly dArg[Hyp3, Thi5, dTic7, Oic8]BK (HOE 140, pKB 9.3), (E)-3-(6-acetoamido-3-pyridyl)-N-(N-{2, 4-dichloro-3-[(2-methyl-8-quinolinyl)oxy-methyl]phenyl}-N-methylaminocarbonylmethyl)acrylamide (FR 173657), a new non peptide compound (pK B 9.3), while B1 receptor antagonists (e.g. Lys[Leu8]desArg9BK) are inactive. The order of potency of kinin-related peptides in this vessel is: LysBK ≥ BK > [Hyp3]BK>[Aib7]BK, a sequence typical of a B2 receptor system. Antagonists such as HOE 140 and FR 173657, at high concentrations reduce the maximum effect of BK and thus behave as noncompetitive antagonists. The kinin B1 receptor was studied in the pig renal vein without endothelium and incubated for several hours in order to allow for the de novo formation of this functional site. After 7–8 h in vitro incubation, the vessel shows high sensitivity to LysdesArg9BK (pEC50 8.3) and is insensitive to BK. The pig renal vein responds to B1 receptor agonists with concentration-dependent contraction which maintains a stable plateau and is prevented by selective B1 receptor antagonists such as Lys[Leu8]desArg9BK (pKB 6.7). The most active antagonist has been found to be desArg9HOE 140 (pA2 7.6) which acts as competitive antagonist in this preparation. Some B2 antagonists (e.g. HOE 140) show weak (pK B 6.1) anti-B1 receptor activity while the non-peptide compound FR 173657 is inactive on the B1 receptor and therefore acts as a potent and selective kinin B2 receptor antagonist in the pig. The data obtained in this study allow us to compare the porcine B2 and B1 receptors with those of other species including man, and underline some interesting features that are unique to the porcine functional sites.

Purpose:Smooth muscle reactivity is one of the factors involved in the pathogenesis of varicose veins. We investigated the myotropic effects of the 3 main vasoconstrictor agents—norepinephrine (NE), angiotensin II (Ang II), and endothelin-1 (ET-1)—in isolated human saphenous veins. Methods:Human saphenous veins were collected from 23 patients with primary chronic venous insufficiency who underwent elective varicose vein resections and who were stratified into the following 3 groups: group 1, 7 patients in clinical class 2; group 2, 9 patients in clinical classes 3 and 4; and group 3, 7 patients in clinical classes 5 and 6. Moreover, 6 patients who underwent arterial bypass grafting procedures represented the control group. The tissues were suspended in organ baths that contained Krebs solution, and their mechanical responses were measured isometrically. The cumulative concentration–response curves to Ang II, NE, and ET-1 were performed at 90-minute intervals in each tissue. Results:In the control tissues, NE, Ang II, and ET-1 induced concentration-dependent contractions with apparent affinities (pEC50, the negative logarithm to base 10 of the molar concentration of the agonist, which produces the 50% of the maximal effect) and maximal effects (maximum effect, g of contraction) that were equal to 7.06 ± 0.23, 8.53 ± 0.34, 7.63 ± 0.10, and 2.21 ± 0.33, 1.65 ± 0.31, 2.60 ± 0.77, respectively. Two main findings were evident in comparison of varicose veins with control tissues. First, the maximum effect that was evoked by all of the stimulants was reduced progressively with the increasing severity of the disease, which raised the third group to statistical significance for both NE and Ang II (P< .05). Second, a marked reduction of Ang II apparent affinity was already evident in tissues that were taken from patients in an early stage of the disease (P< .05). Conclusion:The demonstration of a significant reduction in Ang II and NE contractile activities and the important reduction of that of ET-1 in the diseased veins as compared with the control tissues extends the previous observations regarding the impairment of smooth muscle contractility in primary chronic venous insufficiency. Moreover, the dramatic reduction of Ang II affinity, which appears in an early stage of the disease, supports the hypothesis that such abnormality within the venous wall could play a role in the pathogenesis of primary varicose vein disease. (J Vasc Surg 1998;28:855-61.)

We propose a rigorous procedure to obtain the distribution function of a macroscopic system of microstates in contact with a thermal bath, namely the Gibbs canonical distribution, supposing the validity of the microcanonical distribution for the whole system.

Within the classical statistical physics, we suggest a possible use of the first-order Bessel functions with complex argument to investigate the behaviour of a two-component particle system in thermodynamic equilibrium.

A holographic method for detecting detached regions between the priming layers and the underlying wood support in panel paintings is described. Experimental results obtained by the application of the method both on laboratory models and on an ancient Italian panel painting are presented. The great advantages that this technique can offer to the conservation and restoration of works of art are emphasized.

An automatic densitometer for measuring density of films used in photographic personal dosimetry has been designed and set up. Its main features are: (1) high sensitivity, i.e. the minimum detectable difference in density is small, (2) a wide range of blackening and (3) good long-term stability. Film reading, printing out and reloading operations are fully automatic. The photosensitive part is a photoresistor.

This work aims to measure the neutron spectrum from a RaD-Be source with the nuclear emulsion technique. This technique allows spectrum measurements of fast neutrons with a good energy resolution and can be used also for wide and uncollimated sources, such as in the case of «in core» neutron fluxes. The plate chosen is a 200 µm thick Ilford K2, on a glass mount. The method is basedo n the determination of the track lengths of recoil protons from elastic scattering of neutrons on hydrogen nuclei of the emulsion. The differential spectrum obtained has 0.2 MeV channel width. Statistical errors are not larger than 7% for 85% of the channels taken into account in this case.