Dynamic Interfaces in Self-Healable Polymers.

It is well-established that interfaces play critical roles in biological and synthetic processes. Aside from significant practical applications, the most accessible and measurable quantity is interfacial tension, which represents a measure of the energy required to create or rejoin two surfaces. Owing to the fact that interfacial processes are critical in polymeric materials, this review outlines recent advances in dynamic interfacial processes involving physics and chemistry targeting self-healing. Entropic interfacial energies stored during damage participate in the recovery, and self-healing depends upon copolymer composition and monomer sequence, monomer molar ratios, molecular weight, and polymer dispersity. These properties ultimately impact chain flexibility, shape-memory recovery, and interfacial interactions. Self-healing is a localized process with global implications on mechanical and other properties. Selected examples driven by interfacial flow and shape memory effects are discussed in the context of covalent and supramolecular rebonding targeting self-healable materials development.

Fluorophilic Sigma(σ)-Lock Self-Healable Copolymers.

Although F-Containing molecules and macromolecules are often used in molecular biology to increase the binding with Lewis acidic groups by introducing favorable C-F dipoles, there is virtually no experimental evidence and limited understanding of the nature of these interactions, especially their role in synthetic polymeric materials. These studies elucidate the molecular origin of inter- and intra-Chain interactions responsible for self-healing of F-Containing copolymers composed of pentafluorostyrene and n-butyl acrylate units (p(PFS/nBA). Guided by dynamic surface oscillating force (SOF) and spectroscopic measurements supported by molecular dynamics (MD) simulations, these studies show that the reformation of σ-σ orbitals in -C-F of PFS and CH3CH2- of nBA units enables the recovery of entropic energy via fluorophilic-σ-lock van der Waals forces when PFS/nBA molar ratios are ~50/50. The strength of these interactions determined experimentally for self-healable PFS/nBA compositions is in the order ~0.3 kcal/mol which primarily comes from fluorophilic-σ-lock (~70 %) contributions. These interactions are significantly diminished for non-self-healable counterparts. Strongly polarized -C-F σ orbitals create lateral dipolar forces enhancing the affinity towards -C-H orbitals, facilitating energetically favorable interactions. Entropic recovery driven by non-Covalent bonding offers a valuable tool in designing materials with unique functionalities, particularly self-healable batteries and energy storage devices.

Ring-and-Lock Interactions in Self-Healable Styrenic Copolymers.

Commodity copolymers offer many useful applications, and their durability is critical in maintaining desired functions and retaining sustainability. These studies show that primarily alternating styrene/n-butyl acrylate [p(Sty/nBA)] copolymers self-heal without external intervention when monomer molar ratios are within the 45:55-53:47 range. This behavior is attributed to the favorable interchain interactions between aliphatic nBA side groups being sandwiched by aromatic rings forming ring-and-lock associations driven by pi-sigma-pi (π-σ-π) interactions. Guided by molecular dynamics (MD) simulations combined with spectroscopic and thermomechanical analysis, the ring-and-lock interchain van der Waals forces between π orbitals of aromatic rings and sigma components of aliphatic side groups are responsible for self-healing. Despite the frequent occurrence of these interactions in biological systems (proteins, nucleic acids, lipids, and polysaccharides), these largely unexplored weak and ubiquitous molecular forces between the soft acid aliphatic and soft base aromatic electrons may be valuable assets in the development of polymeric materials with sustainable properties.

Epinephrine autoinjector prescribing following anaphylaxis presentation to the emergency department.

Background: Guidelines recommend patients with anaphylaxis are prescribed epinephrine autoinjectors (EAI), carry the EAI with them, and are referred to an allergist. There also are barriers to EAI administration, such as acquiring the medication, having it available, recognizing when to use it, and administering it appropriately. Objective: The objective was to describe how often patients with anaphylaxis discharged from the emergency department (ED) receive an EAI prescription and allergist referral; also, to assess the frequency of EAI pick-up by the patient from the outpatient pharmacy, out-of-pocket cost, change in EAI device during dispensing, and if patient training on EAI use and allergist follow-up occurred. Patient-specific factors associated with the occurrence of these variables were investigated. Methods: This was a retrospective, observational study of adult and pediatric ED patients who presented with anaphylaxis between July and December 2020. Data were collected from medical records and telephone calls to outpatient pharmacies and included patient demographics; ED treatment; EAI prescribing, EAI pick-up from the outpatient pharmacy, and cost; device changes; EAI training; and allergist referral and follow-up. Data are presented descriptively, and bivariate analyses were used for comparisons between patient-specific factors and incidence of EAI prescribing, patient pick-up, and allergist referral. Results: A total of 102 patients were included; mean age ± standard deviation 34 ± 7 years, 52% were < 18 years of age; and 54% had a history of allergy and/or anaphylaxis. EAI prescribing occurred in 79% of the patients. Of these, 71% picked up the EAI from the outpatient pharmacy, the median cost to the patient was $5 (range, $0-$379), 18% had an EAI device change at dispensing, and 23% received EAI training. Allergist referral occurred in 22%, and 28% followed up with an allergist within 60 days. Presenting symptoms of mucosal edema and respiratory stridor were associated with the occurrence of EAI prescribing. Presenting symptoms of respiratory wheezing, hoarseness, throat itching, skin flushing and allergist referral from the ED were associated with the occurrence of EAI pick-up from the outpatient pharmacy. Conclusion: Overall, 79% of ED patients with anaphylaxis had an EAI prescribed and 22% had an allergist referral; 71% picked up the EAI from the outpatient pharmacy, EAI dispensing changes occurred, and training was infrequent. Collaboration between emergency medicine clinicians, allergists, and pharmacists is needed to streamline treatment and follow-up.

Raman Spectroscopy as a Potential Adjunct of Thyroid Nodule Evaluation: A Systematic Review.

The incidence of thyroid nodules (TNs) is estimated at 36.5% and 23% in females and males, respectively. A single thyroid nodule is usually detected during ultrasound assessment in patients with symptoms of thyroid dysfunction or neck mass. TNs are classified as benign tumours (non-malignant hyperplasia), benign neoplasms (e.g., adenoma, a non-invasive follicular tumour with papillary nuclear features) or malignant carcinomas (follicular cell-derived or C-cell derived). The differential diagnosis is based on fine-needle aspiration biopsies and cytological assessment (which is burdened with the bias of subjectivity). Raman spectroscopy (RS) is a laser-based, semiquantitative technique which shows for oscillations of many chemical groups in one label-free measurement. RS, through the assessment of chemical content, gives insight into tissue state which, in turn, allows for the differentiation of disease on the basis of spectral characteristics. The purpose of this study was to report if RS could be useful in the differential diagnosis of TN. The Web of Science, PubMed, and Scopus were searched from the beginning of the databases up to the end of June 2023. Two investigators independently screened key data using the terms "Raman spectroscopy" and "thyroid". From the 4046 records found initially, we identified 19 studies addressing the differential diagnosis of TNs applying the RS technique. The lasers used included 532, 633, 785, 830, and 1064 nm lines. The thyroid RS investigations were performed at the cellular and/or tissue level, as well as in serum samples. The accuracy of papillary thyroid carcinoma detection is approx. 90%. Furthermore, medullary, and follicular thyroid carcinoma can be detected with up to 100% accuracy. These results might be biased with low numbers of cases in some research and overfitting of models as well as the reference method. The main biochemical changes one can observe in malignancies are as follows: increase of protein, amino acids (like phenylalanine, tyrosine, and tryptophan), and nucleic acid content in comparison with non-malignant TNs. Herein, we present a review of the literature on the application of RS in the differential diagnosis of TNs. This technique seems to have powerful application potential in thyroid tumour diagnosis.

An Oncoplastic Approach to Primary Pediatric Pterygomaxillary Osteosarcoma.

Osteosarcomas arising within the pterygomaxillary/infratemporal fossa region are rare among the pediatric population. Survival rates are most influenced by tumor resection with negative margins, which can be dependent on surgical accessibility of the tumor site. The pterygomaxillary/infratemporal fossa location poses several challenges to safe and adequate tumor resection, including proximity of the facial nerve and great vessels and scarring associated with traditional transfacial approaches. In this article, we present the case of a 6-year-old boy with an osteosarcoma of the left pterygomaxillary/infratemporal fossa region successfully managed with an "oncoplastic" approach, incorporating the use of CAD/CAM and mixed reality technologies.

Electrically Accelerated Self-Healable Polyionic Liquid Copolymers.

Electrically accelerated self-healable poly(ionic liquids) copolymers that exhibit resistor-capacitor (RC) circuit properties are developed. At low alternating current (AC) frequencies these materials behave as a resistor (R), whereas at higher frequencies as a capacitor (C). These properties are attributed to a combination of dipolar and electrostatic interactions in (1-[(2-methacryloyloxy)ethyl]-3-butylimidazolium bis(trifluoromethyl-sulfonyl)imide) copolymerized with methyl methacrylate (MMA) monomers to form p(MEBIm-TSFI/MMA)] copolymers. When the monomer molar ratio (MEBIm-TSFI:MMA) is 40/60, these copolymers are capable of undergoing multiple damage-repair cycles and self-healing is accelerated by the application of alternating 1.0-4.0 V electric field (EF). Self-healing in the absence of EFs is facilitated by van der Waals (vdW) interactions, but the application of AC EF induces back and forth movement of charges against the opposing force that result in dithering of electrostatic dipoles giving rise to interchain physical crosslinks. Electrostatic inter- and intrachain interactions facilitated by copolymerization of ionic liquid monomers with typically dielectric acrylic-based monomers result in enhanced cohesive energy densities that accelerate the recovery of vdW forces facilitating self-healing. Incorporating ionic liquids into commodity polymers offers promising uses as green conducting solid polyelectrolytes in self-healable energy storage, energy-harvesting devices, and many other applications.

Heart Rate Variability After Sprint Interval Training in Cyclists and Implications for Assessing Physical Fatigue.

ABSTRACT: Hebisz, RG, Hebisz, P, and Zaton, MW. Heart rate variability after sprint interval training in cyclists and implications for assessing physical fatigue. J Strength Cond Res 36(2): 558-564, 2022-This study evaluated the time- and frequency-domain indexes of heart rate variability (HRV) during sprint interval exercise test (SIXT) and identify the onset of fatigue by HRV concurrent with changes in average (Pavg) and peak (Ppeak) power output, total oxygen uptake (V̇o2tou), and blood hydrogen (H+) and lactate (La-) concentrations. Twenty-seven cyclists performed 4 sets of SIXT in which each set consisted of four 30-second maximal sprints interspersed with 90 seconds of low-intensity cycling. Each set was separated by 25-40 minutes of recovery. Before beginning each set, HRV was analyzed by time (mean normal-to-normal RR intervals [RRNN], SD of normal-to-normal RR intervals [SDNN], and square root of the mean squared difference between successive normal-to-normal RR intervals [RMSSD]) and frequency (total spectral power [T] and very low- [VLF], low- [LF], and high-frequency [HF] spectral power) domain methods. Pavg, Ppeak, and V̇o2tou were recorded in each set, and H+ and La- were measured after each set. RRNN, SDNN, and VLF decreased in the second set, whereas all time and frequency indexes of HRV decreased in the third and fourth set. Pavg and H+ decreased, while V̇o2tou increased in the fourth set. Ppeak decreased in the second, third, and fourth set. Correlations were found between the changes in the time and frequency indexes of HRV with H+, La-, and V̇o2tou. The results indicate that HRV does not reflect the onset of physical fatigue in SIXT as was observed in Pavg and no correlation was found between the changes in HRV with Pavg and Ppeak.

Recent Advances in Stimuli-Responsive Commodity Polymers.

Known for their adaptability to surroundings, capability of transport control of molecules, or the ability of converting one type of energy to another as a result of external or internal stimuli, responsive polymers play a significant role in advancing scientific discoveries that may lead to an array of diverge applications. This review outlines recent advances in the developments of selected commodity polymers equipped with stimuli-responsiveness to temperature, pH, ionic strength, enzyme or glucose levels, carbon dioxide, water, redox agents, electromagnetic radiation, or electric and magnetic fields. Utilized diverse applications ranging from drug delivery to biosensing, dynamic structural components to color-changing coatings, this review focuses on commodity acrylics, epoxies, esters, carbonates, urethanes, and siloxane-based polymers containing responsive elements built into their architecture. In the context of stimuli-responsive chemistries, current technological advances as well as a critical outline of future opportunities and applications are also tackled.

Directional Atherectomy of the Common Femoral Artery: Complications and Outcomes.

BACKGROUND: The use of directional atherectomy (DA) with or without drug-coated balloon (DCB) may be considered for the management of common femoral artery (CFA) occlusive disease because of its minimally invasive nature with early mobilization, reduced incision complications, and infection rates. However, it has recognized complications, which may be related to the learning curve. We present our initial experience using DA and suggest changes that may, based on our practice, improve outcomes. METHODS: Retrospective analysis with a prospective data collection from 2 centers to analyze outcomes in all consecutive patients treated during 1 year (n = 25). Patients who underwent CFA DA with/without DCB for CFA >70% stenosis. Primary end points include technical success, primary patency of the CFA, morbidity, and mortality. Secondary end points include change in Rutherford-Becker class, length of stay, and target lesion revascularization rate. RESULTS: Between July 2017 and December 2018, 25 patients underwent CFA DA. Two had an occluded CFA, and 23 had >70% CFA stenosis as determined by ultrasound scan (USS) and/or computed tomography angiogram (CTA) preoperatively. There were no deaths within 30 days. Procedure-related complications included 2 cases of CFA pseudoaneurysm (one of them repaired by open surgery) and 1 CFA perforation (repaired with covered stent). No distal embolization or limb loss occurred. Mean length of stay was 1.9 days. Primary and secondary patency at 3 and 6 months was 100%. At 12 months, it was 96%. CONCLUSIONS: Early results suggest that CFA DA with/without DCB is safe and effective. Previous CTA, focused USS, and/or intravascular USS may be useful to minimize the risk of pseudoaneurysm or perforation by excessive thinning of the media. Experience is required to prevent localized dilatation over time.

Breast cancer risk (un)awareness among women suffering from neurofibromatosis type 1 in Poland.

The main goal of this study was to draw the attention of physicians to commonly undisclosed risk of breast cancer (BrCa) in women suffering from neurofibromatosis type 1 (NF-1), which is 5-fold higher than in the general population. NF-1 related BrCa arises earlier (< 50 years) and is more advanced, with an increased mortality. NF-1 is one of the most frequent monogenic diseases worldwide and a tumor predisposition syndrome. The Nf1 gene is an important negative regulator of the Ras oncogene and belongs to the family of the 12 the most important BrCa predisposition genes. Planning introduction of BrCa screening guidelines for NF-1 women in Poland we started with assessment of BrCa risk awareness and current preventive practices in this population by a survey published in an open access internet profile dedicated exclusively to patients with NF-1 in Poland, with 1928 participants. As a result, we revealed that the awareness of this specific risk was declared by only 30% out of 138 responders, and only 21% of them received this information from medical professionals. In all 4 (2.89%) women suffering from BrCa the cancer was diagnosed before the 50th year of age. It exceeds significantly the expected prevalence of BrCa in the general population of Polish women. We conclude that the limited awareness of NF-1 related BrCa risk in Polish patients warrants the educational effort directed both to the NF-1 patients by professional counseling and to the medical community, in order to increase the efficacy of preventive measures and decrease BrCa mortality.

Optical properties of cubic blue phase liquid crystal in photonic microstructures.

In this work, optical properties of a cubic blue phase liquid crystal (BPLC) in photonic microstructures were investigated. The experiments were carried out in microcapillaries with different inner diameters and in a photonic crystal fiber (PCF). For the first time, white-light beam propagation through a BPLC (BP II) in a microcapillary with a 60-µm inner diameter at a distance of 26 mm was demonstrated. Furthermore, it was conclusively shown that the cylindrical geometry and the size of its inner diameter influence BP domains orientation, which can lead to a uniform texture of the BPLC with a dominant Bragg wavelength. This study also proves that a BPLC-filled PCF provides very attractive tunable properties. It was presented that by applying an external electric field, a control of the transmitted light intensity for particular wavelengths can be achieved, depending on the input polarization. Moreover, a range of the wavelengths corresponding to low transmission appeared to be tunable, whereas for x- and y-polarized light, respectively, both narrowing (from 16 nm to 9 nm) as well widening (from 13 nm to 22 nm) of the bandgaps were observed. Finally, the obtained experimental results were found qualitatively consistent.

A Technique of "Chimney Nellix" for the Management of Type 1a Endoleak After EVAR.

This report presents 3 procedures with visceral "chimney stenting" in conjunction with an endovascular aneurysm sealing (EVAS) device, known as chEVAS, for treatment of type 1a endoleak. It includes the first published chEVAS in a patient with previous fenestrated endovascular aneurysm repair (FEVAR). Cases include an 80-year-old man 8 years after FEVAR for a juxtarenal abdominal aortic aneurysm (AAA); an 85-year-old woman 9 months after endovascular aneurysm repair (EVAR) for a ruptured infrarenal AAA; and an 84-year-old woman 3 months after EVAR for a symptomatic infrarenal AAA. Technical success was achieved in all cases, with 1 postoperative death. The remaining 2 patients had no residual type 1a endoleak at 10 and 14 months respectively.

Platelet microaggregation in sepsis examined by quartz crystal microbalance with dissipation technology.

Antiplatelet therapies remain an area of potential interest for the treatment of sepsis; however, studies of platelet aggregation in sepsis have yielded conflicting results. We examined platelet aggregation patterns in patients with septic shock using quartz crystal microbalance with dissipation technology, a microfluidic device capable of measuring platelet microaggregate formation under flow conditions. Platelet aggregation was increased in the washed platelet samples of septic patients. Conversely, these same platelets aggregated less than healthy controls when examined in their plasma.

Stimuli-Responsive Polymeric Nanoparticles.

There is increasing evidence that stimuli-responsive nanomaterials have become significantly critical components of modern materials design and technological developments. Recent advances in synthesis and fabrication of stimuli-responsive polymeric nanoparticles with built-in stimuli-responsive components (Part A) and surface modifications of functional nanoparticles that facilitate responsiveness (Part B) are outlined here. The synthesis and construction of stimuli-responsive spherical, core-shell, concentric, hollow, Janus, gibbous/inverse gibbous, and cocklebur morphologies are discussed in Part A, with the focus on shape, color, or size changes resulting from external stimuli. Although inorganic/metallic nanoparticles exhibit many useful properties, including thermal or electrical conductivity, catalytic activity, or magnetic properties, their assemblies and formation of higher order constructs are often enhanced by surface modifications. Section B focuses on selected surface reactions that lead to responsiveness achieved by decorating nanoparticles with stimuli-responsive polymers. Although grafting-to and grafting-from dominate these synthetic efforts, there are opportunities for developing novel synthetic approaches facilitating controllable recognition, signaling, or sequential responses. Many nanotechnologies utilize a combination of organic and inorganic phases to produce ceramic or metallic nanoparticles. One can envision the development of new properties by combining inorganic (metals, metal oxides) and organic (polymer) phases into one nanoparticle designated as "ceramers" (inorganics) and "metamers" (metallic).

Instantaneous Directional Growth of Block Copolymer Nanowires During Heterogeneous Radical Polymerization (HRP).

Polymeric nanowires that consist of ultrahigh molecular weight block copolymers were instantaneously prepared via one-step surfactant-free heterogeneous radical polymerization (HRP). Under heterogeneous reaction and initiator-starvation conditions, the sequential copolymerization of hydrophilic and hydrophobic monomers facilitates the formation of amphiphilic ultrahigh molecular weight block copolymers, which instantaneously assemble to polymeric nanowires. As polymerization progresses, initially formed nanoparticles exhibit the directional growth due to localized repulsive forces of hydrophilic blocks and confinement of the hydrophobic blocks that adopt favorable high aspect ratio nanowire morphologies. Using one-step synthetic approach that requires only four ingredients (water as a solvent, two polymerizable monomers (one hydrophilic and one hydrophobic), and water-soluble initiator), block copolymer nanowires ∼70 nm in diameter and hundreds of microns in length are instantaneously grown. For example, when 2-(N,N-dimethylamino)ethyl methacrylate (DMAEMA) and styrene (St) were copolymerized, high aspect ratio nanowires consist of ultrahigh (>10(6) g/mol) molecular weight pDMAEMA-b-St block copolymers and the presence of temperature responsive pDMAEMA blocks facilitates nanowire diameter changes as a function of temperature. These morphologies may serve as structural components of the higher order biological constructs at micro and larger length scales, ranging from single strand nanowires to engineered biomolecular networks capable of responding to diverse and transient environmental signals, and capable of dimensional changes triggered by external stimuli.

Chromatin reprogramming during the somatic-to-reproductive cell fate transition in plants.

The life cycle of flowering plants is marked by several post-embryonic developmental transitions during which novel cell fates are established. Notably, the reproductive lineages are first formed during flower development. The differentiation of spore mother cells, which are destined for meiosis, marks the somatic-to-reproductive fate transition. Meiosis entails the formation of the haploid multicellular gametophytes, from which the gametes are derived, and during which epigenetic reprogramming takes place. Here we show that in the Arabidopsis female megaspore mother cell (MMC), cell fate transition is accompanied by large-scale chromatin reprogramming that is likely to establish an epigenetic and transcriptional status distinct from that of the surrounding somatic niche. Reprogramming is characterized by chromatin decondensation, reduction in heterochromatin, depletion of linker histones, changes in core histone variants and in histone modification landscapes. From the analysis of mutants in which the gametophyte fate is either expressed ectopically or compromised, we infer that chromatin reprogramming in the MMC is likely to contribute to establishing postmeiotic competence to the development of the pluripotent gametophyte. Thus, as in primordial germ cells of animals, the somatic-to-reproductive cell fate transition in plants entails large-scale epigenetic reprogramming.

Pharmacokinetics and bio-distribution of novel super paramagnetic iron oxide nanoparticles (SPIONs) in the anaesthetized pig.

Manufactured nanomaterials have a variety of medical applications, including diagnosis and targeted treatment of cancer. A series of experiments were conducted to determine the pharmacokinetic, biodistribution and biocompatibility of two novel magnetic nanoparticles (MNPs) in the anaesthetized pig. Dimercaptosuccinic acid (DMSA) coated superparamagnetic iron oxide nanoparticles (MF66-labelled 12 nm, core nominal diameter and OD15 15 nm); at 0.5, or 2.0 mg/kg) were injected intravenously. Particles induced a dose-dependent decrease in blood pressure following administration which recovered to control levels several minutes after injection. Blood samples were collected for a 5-h period and stored for determination of particle concentration using particle electron paramagnetic resonance (pEPR). Organs were harvested post-mortem for magnetic resonance imaging (MRI at 1.5 T field strength) and histology. OD15 (2.0 mg/kg) MNP had a plasma half-life of approximately 15 min. Both doses of the MF66 (0.5 and 2.0 mg/kg) MNP were below detection limits. MNP accumulation was observed primarily in the liver and spleen with MRI scans which was confirmed by histology. MRI also showed that both MNPs were present in the lungs. The results show that further modifications may be required to improve the biocompatibility of these particles for use as diagnostic and therapeutic agents.

Effects of extreme natural events on the provision of ecosystem services in a mountain environment: The importance of trail design in delivering system resilience and ecosystem service co-benefits.

A continued supply of ecosystem services (ES) from a system depends on the resilience of that system to withstand shocks and perturbations. In many parts of the world, climate change is leading to an increased frequency of extreme weather events, potentially influencing ES provision. Our study of the effects of an intense rainfall event in Gorce National Park, Poland, shows: (1) the intense rainfall event impacted heavily on the supply of ES by limiting potential recreation opportunities and reducing erosion prevention; (2) these negative impacts were not only restricted to the period of the extreme event but persisted for up to several years, depending on the pre-event trail conditions and post-event management activities; (3) to restore the pre-event supply of ES, economic investments were required in the form of active repairs to trails, which, in Gorce National Park, were an order of magnitude higher than the costs of normal trail maintenance; and (4) when recreational trails were left to natural restoration, loss of biodiversity was observed, and recovery rates of ES (recreation opportunities and soil erosion prevention) were reduced in comparison to their pre-event state. We conclude that proper trail design and construction provides a good solution to avoid some of the negative impacts of extreme events on recreation, as well as offering co-benefits in terms of protecting biodiversity and enhancing the supply of regulating services such as erosion prevention.

Nitric oxide-matrix metaloproteinase-9 interactions: biological and pharmacological significance--NO and MMP-9 interactions.

Nitric oxide (NO) and matrix metalloproteinase 9 (MMP-9) levels are found to increase in inflammation states and in cancer, and their levels may be reciprocally modulated. Understanding interactions between NO and MMP-9 is of biological and pharmacological relevance and may prove crucial in designing new therapeutics. The reciprocal interaction between NO and MMP-9 have been studied for nearly twenty years but to our knowledge, are yet to be the subject of a review. This review provides a summary of published data regarding the complex and sometimes contradictory effects of NO on MMP-9. We also analyse molecular mechanisms modulating and mediating NO-MMP-9 interactions. Finally, a potential therapeutic relevance of these interactions is presented.