Protamine-grafted carboxymethyl chitosan based hydrogel with adhesive and long-term antibacterial properties for hemostasis and skin wound healing

In this study, we developed a tissue-adhesive and long-term antibacterial hydrogel consisting of protamine (PRTM) grafted carboxymethyl chitosan (CMC) (PCMC), catechol groups modified CMC (DCMC), and oxidized hyaluronic acid (OHA), named DCMC-OHA-PCMC. According to the antibacterial experiments, the PCMC-treated groups showed obvious and long-lasting inhibition zones against E. coli (and S. aureus), and the corresponding diameters varied from 10.1 mm (and 15.3 mm) on day 1 to 9.8 mm (and 15.3 mm) on day 7. The DCMC-OHA-PCMC hydrogel treated groups also exhibited durable antibacterial ability against E. coli (and S. aureus), and the antibacterial rates changed from 99.3 ± 0.21 % (and 99.6 ± 0.36 %) on day 1 to 76.2 ± 1.74 % (and 84.2 ± 1.11 %) on day 5. Apart from good mechanical and tissue adhesion properties, the hydrogel had excellent hemostatic ability mainly because of the grafted positive-charged PRTM. As the animal assay results showed, the hydrogel was conducive to promoting the deposition of new collagen (0.84 ± 0.03), the regeneration of epidermis (98.91 ± 6.99 μm) and wound closure in the process of wound repairing. In conclusion, the presented outcomes underline the prospective potential of the multifunctional CMC-based hydrogel for applications in wound dressings.

"Rich arginine and strong positive charge" antimicrobial protein protamine: From its action on cell membranes to inhibition of bacterial vital functions

Protamine, an antimicrobial protein derived from salmon sperm with a molecular weight of approximately 5 kDa, is composed of 60-70 % arginine and is a highly charged protein. Here, we investigated the mechanism of antimicrobial action of protamine against Cutibacterium acnes (C. acnes) focusing on its rich arginine content and strong positive charge. Especially, we focused on the attribution of dual mechanisms of antimicrobial protein, including membrane disruption or interaction with intracellular components. We first determined the dose-dependent antibacterial activity of protamine against C. acnes. In order to explore the interaction between bacterial membrane and protamine, we analyzed cell morphology, zeta potential, membrane permeability, and the composition of membrane fatty acid. In addition, the localization of protamine in bacteria was observed using fluorescent-labeled protamine. For investigation of the intracellular targets of protamine, bacterial translation was examined using a cell-free translation system. Based on our results, the mechanism of the antimicrobial action of protamine against C. acnes is as follows: 1) electrostatic interactions with the bacterial cell membrane; 2) self-internalization into the bacterial cell by changing the composition of the bacterial membrane; and 3) inhibition of bacterial growth by blocking translation inside the bacteria. However, owing to its strong electric charge, protamine can also interact with DNA, RNA, and other proteins inside the bacteria, and may inhibit various bacterial life processes beyond the translation process.

Systemic delivery of proteins using novel peptides via the sublingual route

Therapeutic proteins often require needle-based injections, which compromise medication adherence especially for those with chronic diseases. Sublingual administration provides a simple and non-invasive alternative. Herein, two novel peptides (lipid-conjugated protamine and a protamine dimer) were synthesized to enable sublingual delivery of proteins through simple physical mixing with the payloads. It was found that the novel peptides promoted intracellular delivery of proteins via increased pore formation on the cell surface. Results from in vitro models of cell spheroids and human sublingual tissue substitute indicated that the novel peptides enhanced protein penetration through multiple cell layers compared to protamine. The novel peptides were mixed with insulin or semaglutide and sublingually delivered to mice for blood glucose (BG) control. The effects of these sublingual formulations were comparable to the subcutaneous preparations and superior to protamine. In addition to peptide drugs, the novel peptides were shown to enable sublingual absorption of larger proteins with molecular weights from 22 to 150 kDa in mice, including human recombinant growth hormone (rhGH), bovine serum albumin (BSA) and Immunoglobulin G (IgG). The novel peptides given sublingually did not induce any measurable toxicities in mice.

Polyphosphate coated nanoparticles: Enzyme-activated charge-reversal gene delivery systems

AIM

The current study aimed to develop enzyme-activated charge-reversal lipid nanoparticles (LNPs) as novel gene delivery systems.

METHODS

Palmitic acid was covalently bound to protamine being utilised as transfection promoter to anchor it on the surfaces of LNPs. Green fluorescent protein (GFP) encoding plasmid DNA (pDNA) was ion paired with various cationic counter ions to achieve high encapsulation in LNPs. Protamine-decorated LNPs were prepared by solvent injection method followed by coating with sodium tripolyphosphate (TPP) to generate a bio-inert anionic outer surface. Resulting LNPs were characterised regarding size, polydispersity, zeta potential and encapsulation efficiency. Enzyme-triggered charge-reversal of LNPs was investigated using isolated alkaline phosphatase (ALP) monitoring changes in zeta potential as well as monophosphate release. Furthermore, monophosphate release, cell viability and transfection efficiency were evaluated on a human alveolar epithelial (A549) cell line.

RESULTS

Protamine-decorated and TPP-coated (Prot-pDNA/DcChol-TPP) LNPs displayed a mean size of 298.8 ± 17.4 nm and a zeta potential of -13.70 ± 0.61 mV. High pDNA encapsulation was achieved with hydrophobic ion pairs of pDNA with 3ß-[N-(N',N'-dimethylaminoethane)-carbamoyl]cholesterol hydrochloride (DcChol). Zeta potential of Prot-pDNA/DcChol-TPP LNPs reversed to positive values with a total Δ26.8 mV shift upon incubation with ALP. Conformably, a notable amount of monophosphate was released upon incubation of Prot-pDNA/DcChol-TPP LNPs with isolated as well as cell-associated ALP. A549 cells well tolerated LNPs displaying more than 95 % viability. Compared with naked pDNA, unmodified LNPs and control LNPs, Prot-pDNA/DcChol-TPP LNPs showed a significantly increased transfection efficiency.

CONCLUSION

Prot-pDNA/DcChol-TPP LNPs can be regarded as promising gene delivery systems.

Safety of routine protamine in the reversal of heparin in percutaneous coronary intervention: A systematic review and meta-analysis

OBJECTIVES

To determine the safety and efficacy of protamine in the reversal of heparin in percutaneous coronary intervention (PCI).

BACKGROUND

Heparin is routinely used for anticoagulation in PCI. Protamine is not used routinely to reverse heparin's effects in PCI, partly due to the perceived risk of stent thrombosis.

METHODS

Relevant studies published in English were searched for in PubMed, Embase, and Cochrane databases from inception to April 26th, 2023. Our primary outcome of interest was stent thrombosis in patients receiving PCI for all indications. Secondary outcomes included mortality, major bleeding complications, and hospitalization length. Dichotomous outcomes were analyzed using a Mantel-Haenszel random-effects model and expressed as odds ratios (OR) with their 95% confidence intervals (CI), while continuous outcomes were analyzed using an inverse variance random-effects model expressed as mean differences (MD) with their 95% CI.

RESULTS

11 studies were included in our analysis. Protamine use was not associated with stent thrombosis: OR 0.58, 95% CI: 0.33, 1.01 (p = 0.05) nor with mortality (p = 0.89). Protamine administration was associated with a decreased incidence of major bleeding complications: OR 0.48; 95% CI: 0.25, 0.95 (p = 0.03) and decreased length of hospitalization (p < 0.0001).

CONCLUSIONS

In patients pre-treated with dual antiplatelet therapy (DAPT), protamine may be a safe and efficacious option to facilitate earlier sheath removal, reduce major bleeding complications, and reduce length of hospitalization without increased risk of stent thrombosis.

End-on PEGylation of heparin: Effect on anticoagulant activity and complexation with protamine

Heparin is the most common anticoagulant used in clinical practice but shows some downsides such as short half-life (for the high molecular weight heparin) and secondary effects. On the other hand, its low molecular weight analogue cannot be neutralized with protamine, and therefore cannot be used in some treatments. To address these issues, we conjugated polyethylene glycol (PEG) to heparin reducing end (end-on) via oxime ligation and studied the interactions of the conjugate (Hep-b-PEG) with antithrombin III (AT) and protamine. Isothermal titration calorimetry showed that Hep-b-PEG maintains the affinity to AT. Dynamic light scattering demonstrated that the Hep-b-PEG formed colloidal stable nanocomplexes with protamine instead of large multi-molecular aggregates, associated with heparin side effects. The in vitro (human plasma) and in vivo experiments (Sprague Dawley rats) evidenced an extended half-life and higher anticoagulant activity of the conjugate when compared to unmodified heparin.

Determination of protamine and heparin based on their effects on a glucose oxidase enzymatic reaction

This paper describes a sensitive method for determining protamine and heparin by utilizing a glucose oxidase enzymatic reaction. Polycationic protamine significantly promoted the enzymatic reaction rate with [Fe(CN)6]3-, so that the increase could be used to determine protamine. The promotion effect was stoichiometrically decreased by the addition of polyanionic heparin through the polyion complex formation with protamine, so that the enzymatic reaction also allowed for the determination of heparin. We thus applied the proposed method to blood plasma containing heparin and found that heparin did not stoichiometrically form a polyion complex with protamine, likely due to strong interactions between heparin and some components of the plasma. The proposed method allowed for the detection of free protamine (and/or weakly binding protamine with heparin) existing in the condition that protamine did not neutralize all of the heparin in the plasma. The method also permitted for the estimation of heparin concentrations using calibration curves. Thus, the proposed method would help reduce the risks of protamine overdose in heparin neutralization and would be a helpful tool in clinical practices that use heparin and protamine.

In house synthesized novel distyryl-BODIPY dye and polymer assembly as deep-red emitting probe for protamine detection

In this contribution, we designed and synthesized a deep-red emitting distyryl-BODIPY dye (dye 3) which is non-fluorescent in aqueous solution due to the formation of non-emissive aggregates. However, in presence of an amphiphilic polymer (polystyrene sulfonate, PSS), the aggregated dye molecules de-aggregate and form dye 3-PSS complex, which significantly modulates the optical features of the bound dye. Interestingly, the dye 3-PSS complex shows turn-on fluorescence response in deep-red region in presence of protamine (Pr) due to the formation of dye 3-PSS-Pr ternary complex. Such enhancement follows a linear trend in the dynamic range of 0-8.75 μM of Pr which has been utilized to determine Pr with limit of detection (LOD) of 15.04(±0.5) nM in phosphate buffer. Furthermore, excellent selectivity of the dye 3-PSS system towards Pr allows us to determine Pr even in complex biological matrix like 1% human serum. Thus, dye 3-PSS system can be applied as a very effective tool for the detection and quantification of Pr in deep-red region, overcoming several limitations encountered with the probes in the shorter wavelength region. This is the first report on BODIPY dye based supramolecular assembly for sensing and quantification of protamine.

Synergistically enhanced cancer immunotherapy by combining protamine-based nanovaccine with PD-L1 gene silence nanoparticle

Tumor vaccine has brought a new dawn for cancer immunotherapy, but disillusionary therapeutic outcomes have been achieved due to the inefficient in vivo vaccine delivery. Moreover, tumor cells customarily resort to various wily tricks to circumvent the recognition and sweeping of the immune system, the immune escape effect has badly aggravated the difficulty of cancer management. With respect to the foregoing, in this study, a promising combinational strategy which cooperated nanovaccine with immune escape inhibition was developed for synergistically enhancing the oncotherapy efficiency. On the one hand, natural polycationic macromolecule protamine (PRT) was utilized as the carrier to construct an antigen and adjuvant co-packaged nanovaccine for facilitating the ingestion in antigen-presenting cells, amplifying antigen cross-presentation and optimizing in vivo delivery. On the other hand, PD-L1 silence gene was selected and hitchhiked in a pH-responsive nanoparticle developed in our previous study. The therapeutic gene could be successfully delivered into the tumors to down-regulate PD-L1 expression and cripple tumor immune escape. The combination of nanovaccine with PD-L1 gene silence nanoparticle could synchronously stimulate antitumor immune responses and reduce immune escape, synergistically enhance the therapeutic efficiency. This study will furnish the prospective tactics for the research of cancer immunotherapy.

DOT1L promotes spermatid differentiation by regulating expression of genes required for histone-to-protamine replacement

Unique chromatin remodeling factors orchestrate dramatic changes in nuclear morphology during differentiation of the mature sperm head. A crucial step in this process is histone-to-protamine exchange, which must be executed correctly to avoid sperm DNA damage, embryonic lethality and male sterility. Here, we define an essential role for the histone methyltransferase DOT1L in the histone-to-protamine transition. We show that DOT1L is abundantly expressed in mouse meiotic and postmeiotic germ cells, and that methylation of histone H3 lysine 79 (H3K79), the modification catalyzed by DOT1L, is enriched in developing spermatids in the initial stages of histone replacement. Elongating spermatids lacking DOT1L fail to fully replace histones and exhibit aberrant protamine recruitment, resulting in deformed sperm heads and male sterility. Loss of DOT1L results in transcriptional dysregulation coinciding with the onset of histone replacement and affecting genes required for histone-to-protamine exchange. DOT1L also deposits H3K79me2 and promotes accumulation of elongating RNA Polymerase II at the testis-specific bromodomain gene Brdt. Together, our results indicate that DOT1L is an important mediator of transcription during spermatid differentiation and an indispensable regulator of male fertility.

Protamine-mediated efficient transcellular and transmucosal delivery of proteins

Proteins and peptides often require frequent needle-based administrations. Here, we report a non-parenteral delivery method for proteins through physical mixing with protamine, an FDA-approved peptide. Protamine was shown to promote tubulation and rearrangement of cellular actin, leading to enhanced intracellular delivery of proteins compared to poly(arginine)₈ (R8). While the R8-mediated delivery resulted in significant lysosomal accumulation of the cargo, protamine directed the proteins to the nuclei with little lysosomal uptake. Intranasal delivery of insulin mixed with protamine effectively reduced blood glucose levels in diabetic mice 0.5 h after administration and the effect lasted for ∼6 h, comparable to subcutaneously injected insulin at the same dose. In mice, protamine was shown to overcome mucosal and epithelial barriers and modulate adherens junctions, promoting insulin penetration to the lamina propria layer for systemic absorption.

Insulin Therapy in Small Animals, Part 1: General Principles

Understanding the pharmacology of insulin and how it relates to the pathophysiology of diabetes can lead to better clinical outcomes. No insulin formulation should be considered "best" by default. Insulin suspensions (NPH, NPH/regular mixes, lente, and PZI) as well as insulin glargine U100 and detemir are intermediate-acting formulations that are administered twice daily. For a formulation to be an effective and safe basal insulin, its action should be roughly the same every hour of the day. Currently, only insulin glargine U300 and insulin degludec meet this standard in dogs, whereas in cats, insulin glargine U300 is the closest option.

Durably antibacterial cotton fabrics coated by protamine via Schiff base linkages

The development of antibacterial cotton fabrics with an overall performance is critical but remains challenging. In this study, we propose a facile method to prepare durable antibacterial cotton fabric without significant sacrifices of wearing comfortability. Cotton fabric is firstly oxidated to obtain dialdehyde groups, then treated with PM molecules to establish a PM coating on the fiber surfaces via Schiff base linkages. The resultant cotton fabrics show durably antibacterial activity, realizing high bacterial reduction rates against both E. coli and S. aureus higher than 99.99 %, and offering remarkable durabilities tolerable 50 washing cycles and 500 rubbing times. These fabrics also show reliable safety for human skin that proofed by a series of cytotoxicity tests with positive results. This work demonstrates an example of versatile strategy to impart effective antibacterial function with durable activity to cotton textiles, showing great potential for practical applications in functional textile fields.

H1 and H2 antihistamines pretreatment for attenuation of protamine reactions after cardiopulmonary bypass: a randomized-controlled study

BACKGROUND

Protamine administration post-cardiopulmonary bypass (CPB) can potentially cause hemodynamic instability. Histamine released from mast cells is believed to be responsible for hypotension after protamine administration. The aim of this study was to examine the effects of pretreatment with H1 and H2 antihistamines on changes in systemic arterial pressure following protamine administration.

METHODS

This study was a randomized, triple-blinded, placebo-controlled study, conducted at a university hospital. Forty adult patients undergoing elective coronary artery bypass grafting (CABG) or single valve surgery were included. The patients were randomly allocated (20 patients in each group) to receive a single dose of combined chlorpheniramine 10 mg and ranitidine 50 mg or normal saline intravenously immediately after separation from CPB prior to protamine administration. Trajectory changes in systolic blood pressure (SBP), mean arterial pressure (MAP), and vasoactive-inotropic score (VIS) from baseline until 35 minutes following protamine administration (24-time points) were compared between the two groups. Serial serum tryptase levels were also obtained at baseline, 30 and 60 minutes after protamine was given.

RESULTS

Forty patients were included in the analysis. Demographic and baseline blood pressure were similar between the two groups. At 30 minutes after protamine administration, there were no significant differences in both crude SBP [mean difference: -7.1 mmHg, 95% confidence interval (CI), -1.1 to 15.3 mmHg, P=0.09] and SBP after adjustment for the European System for Cardiac Operative Risk Evaluation (EuroSCORE II), CPB time, and VIS (mean difference: -3.9 mmHg, 95% CI, -11.9 to 4.0 mmHg, P=0.33). There were also no significant differences in crude MAP (mean difference: -2.1 mmHg, 95% CI, -6.9 to 2.7 mmHg, P=0.39) and adjusted MAP (mean difference: -0.7 mmHg, -5.9 to 4.4 mmHg, P=0.78) between the two groups. None of the patients in both groups had a significant increase in serum tryptase from baseline. No differences in median serum tryptase levels at baseline, 30 and 60 minutes were demonstrated between the two groups.

CONCLUSIONS

Pretreatment with H1 and H2 antihistamines does not attenuate blood pressure responses to protamine administration in patients after CPB. Mechanisms other than histamine release from mast cells might be responsible for protamine-induced cardiovascular changes.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03583567.

Somatic Cell Nuclear Transfer Using Freeze-Dried Protaminized Donor Nuclei

Somatic cell nuclear transfer (SCNT) is the only nuclear reprogramming method that allows rewinding an adult nucleus into a totipotent state. As such, it offers excellent opportunities for the multiplication of elite genotypes or endangered animals, whose number have shrunk to below the threshold of safe existence. Disappointingly, SCNT efficiency is still low. Hence, it would be wise to store somatic cells from threatened animals in biobanks. We were the first to show that freeze-dried cells allow generating blastocysts upon SCNT. Only a few papers have been published on the topic since then, and viable offspring have not been produced. On the other hand, lyophilization of mammalian spermatozoa has made considerable progress, partially due to the physical stability that protamines provide to the genome. In our previous work, we have demonstrated that a somatic cell could be made more amenable to the oocyte reprogramming by the exogenous expression of human Protamine 1. Given that the protamine also provides natural protection against dehydration stress, we have combined the cell protaminization and lyophilization protocols. This chapter comprehensively describes the protocol for somatic cell protaminization, lyophilization, and its application in SCNT. We are confident that our protocol will be relevant for establishing somatic cells stocks amenable to reprogramming at low cost.

Nanoarchitectonics of Layer-by-Layer (LbL) coated nanostructured lipid carriers (NLCs) for Enzyme-Triggered charge reversal

HYPOTHESIS

Combined usage of Layer-by-Layer (LbL) coating and alkaline phosphatase (ALP) - responsive charge reversal strategies can improve the cellular internalisation of the colloidal drug delivery systems by also decreasing their cytotoxic effects.

EXPERIMENTS

Anionic core NLCs were formed by combining the melt emulsification method and ultrasonication. The resulting core NLCs were coated sequentially first with protamine (Prot NLCs) and then with sodium tripolyphosphate (TPP) or sodium polyphosphate (Graham's salt, PP) generating TPP or PP NLCs, respectively. The developed NLCs were characterised regarding their size and zeta potential. Enzyme-induced charge reversal of the TPP and PP NLCs was evaluated by zeta potential measurements upon their incubation with alkaline phosphatase (ALP). In parallel, time-dependent phosphate release was monitored in the presence of isolated as well as cell-associated ALP. Morphological evaluations were performed by scanning electron microscopy (SEM) studies. Moreover, cell viability and cellular uptake studies were carried out in vitro on Caco-2 cells.

FINDINGS

The core NLCs were obtained with a mean size of 272.27 ± 5.23 nm and a zeta potential of -25.70 ± 0.26 mV. Upon coating with protamine, the zeta potential raised to positive values with a total change up to Δ29.3 mV also displaying an increase in particle size. The second layer coating with TPP and PP provided a negative surface charge. Subsequent to ALP treatment, the zeta potential of the TPP and PP NLCs reversed from negative to positive values with total changes of Δ8.56 and Δ7.47 mV, respectively. Conformably, significant amounts of phosphate were released from both formulations. Compared with core NLCs, improved cellular viability as well as increased cellular uptake were observed in case of Prot, TPP and PP NLCs.

Altered DNA methylation in estrogen-responsive repetitive sequences of spermatozoa of infertile men with shortened anogenital distance

BACKGROUND

It has been suggested that antenatal exposure to environmental endocrine disruptors is responsible for adverse trends in male reproductive health, including male infertility, impaired semen quality, cryptorchidism and testicular cancer, a condition known as testicular dysgenesis syndrome. Anogenital distance (AGD) is an anthropomorphic measure of antenatal exposure to endocrine disruptors, with higher exposure levels leading to shortened AGD. We hypothesized that exposure to endocrine disruptors could lead to changes in DNA methylation during early embryonic development, which could then persist in the sperm of infertile men with shortened AGD.

RESULTS

Using fluorescence activated cell sorting based on staining with either YO-PRO-1 (YOPRO) or chromomycin-3 (CMA3), we isolated four sperm fractions from eleven infertile men with short AGD and ten healthy semen donors. We examined DNA methylation in these sorted spermatozoa using reduced representation bisulfite sequencing. We found that fractions of spermatozoa from infertile men stained with CMA3 or YOPRO were more likely to contain transposable elements harboring an estrogen receptor response element (ERE). Abnormal sperm (as judged by high CMA3 or YOPRO staining) from infertile men shows substantial hypomethylation in estrogenic Alu sequences. Conversely, normal sperm fractions (as judged by low CMA3 or YO-PRO-1 staining) of either healthy donors or infertile patients were more likely to contain hypermethylated Alu sequences with ERE.

CONCLUSIONS

Shortened AGD, as related to previous exposure to endocrine disruptors, and male infertility are accompanied by increased presence of hormonal response elements in the differentially methylated regulatory sequences of the genome of sperm fractions characterized by chromatin decondensation and apoptosis.

Protamine gold nanoclusters - based fluorescence turn-on sensor for rapid determination of Trinitrotoluene (TNT)

Determination of trace residues of 2,4,6-trinitrotoluene (TNT) is an analytical challenge as it is widely used in military, mining industry, civilian and counter-terrorism purposes. In this study, a gold nanocluster - based turn-on fluorescence sensor was developed for TNT determination. A one-pot approach was used to synthesize the fluorescent protamine - stabilized gold nanoclusters (PRT-AuNC). The proposed turn-on fluorometric sensor relies on the aggregation-induced emission enhancement mechanism. As a result of the donor-acceptor interaction between the non-fluorescent Meisenheimer anion formed from TNT and the amino groups of weakly fluorescent protamine, the PRT-AuNCs aggregate and an accompanying enhancement in fluorescence intensity is observed with a large Stokes shift (λ_ex = 300 nm, λ_em = 600 nm). The fluorescence enhancement increased linearly with TNT with an LOD of 12.44 µg/L. Similar energetic materials, common soil ions and explosive camouflage materials did not affect the proposed fluorometric sensing method. TNT in artificially contaminated soil was determined, and the results were comparable to those obtained by the HPLC-DAD system. The proposed turn-on sensor is an important tool for simple, fast, rapid and sensitive TNT determination, and has a potential to be converted to a kit format.

Determination of chlorothalonil levels through inhibitory effect on papain activity at protein-decorated liquid crystal interfaces

A liquid crystal (LC)-based assay was developed to detect chlorothalonil (CHL). The detection principle is based on (i) the electrostatic interaction between the positively charged protein protamine (PRO) with the negatively charged phospholipid dioleoyl-sn-glycero-3-phospho-rac-(1-glycerol) sodium salt (DOPG) and (ii) the CHL-mediated inhibition of papain (PAP) activity. The aqueous/LC interface was decorated with a monolayer of DOPG and PRO that self-assembled via electrostatic interactions. PAP can hydrolyze PRO, resulting in the realignment of an LC by DOPG, inducing a shift in the LC response from bright to dark. The addition of CHL can inhibit the activity of PAP, leading to the attraction of PRO to DOPG and the consequent disruption of the LC orientation. The orientation change of the LC in the presence or absence of CHL can be observed from the changes in its optical appearance using a polarized light microscope. Under optimal conditions, the developed assay achieved a detection limit of 0.196 pg mL⁻¹ within a range of determination of 0.65–200 pg mL⁻¹. The selectivity of the assay was verified in the presence of carbendazim and imidacloprid. The practical application of the proposed assay was demonstrated by its use to determine the levels of CHL in food extracts and environmental samples, which yielded recoveries and relative standard deviations (RSD) in the ranges of 87.39–99.663% and 1.03–6.32%, respectively.

Flower-like ZIF-8 enhance the peroxidase-like activity of nanoenzymes at neutral pH for detection of heparin and protamine

The peroxide-like catalytic activity of gold nanoclusters (Au-NCs) is very low under physiological conditions (pH 7.4), which greatly limits its biological detection applications. A new nanoenzyme platform was constructed by self-assembly of Au-NCs and ZIF-8/CQDs. It was found that heparin can significantly promote the peroxidase-like activity of Au-NCs on the nanoenzyme platform at pH 7.4. In the presence of H₂O₂, the catalytic activity of Au-NCs on the nanoenzyme platform for TMB increased nearly 50 times. Based on this phenomenon, a colorimetric method was developed to determine heparin in the range of 0.0185-9.25 U/mL, with a detection limit of 0.0027 U/mL. When protamine is introduced, heparin and protamine take the lead in specific binding due to antagonism, which makes heparin unable to adsorb on the surface of ZIF-8/CQDS, thus inhibiting the enhancement of the catalytic activity of Au-NCs. Based on this phenomenon, a colorimetric method was developed to determine protamine in the range of 0.01-0.5 μg/mL, with a detection limit of 0.003 μg/mL. Therefore, this method provides a new idea for the visual detection of heparin and protamine under physiological conditions.

Safety and efficacy of immediate heparin reversal with protamine after complex percutaneous coronary intervention

Background

Compared to simple percutaneous coronary intervention (PCI), complex PCI is associated with higher bleeding and thrombotic risk. No previous study has evaluated the use of protamine after PCI with contemporary technologies. This study aimed to evaluate the safety and efficacy of manual compression with and without protamine after transfemoral complex PCI.

Methods

We retrospectively analyzed 160 patients (protamine group, n = 92; non-protamine group, n = 68) who underwent complex PCI via the femoral artery. The primary outcome was a composite of in-hospital death, myocardial infarction, stent thrombosis, stroke/systemic embolism, bleeding requiring blood transfusion, and vascular access complications.

Results

The primary outcome was significantly lower in the protamine group than in the non-protamine group (4.3% vs. 17.6%; p = 0.006). This was driven mainly by the lower incidences of hematoma in the protamine group (3.3% vs. 13.2%, p = 0.020). Furthermore, the protamine group had a significantly shorter hospital stay than the non-protamine group (4.8 ± 3.7 days vs. 8.4 ± 8.3 days, p = 0.001). While > 90% of the patients had acute coronary syndrome, there were no incidences of myocardial infarction or stent thrombosis in either group.

Conclusions

Among patients who underwent complex PCI via transfemoral access, immediate protamine administration was associated with a significantly lower rate of vascular access complications, especially hematoma, and shorter hospital stay than no protamine administration.

The Association of Certain Seminal Phthalate Metabolites on Spermatozoa Apoptosis: An Exploratory Mediation Analysis via Sperm Protamine

Earlier studies have suggested that exposure to phthalates (PAEs) may induce spermatozoa apoptosis. Sperm protamine as a molecular biomarker during spermatozoa apoptotic processes may mediate the association between PAE exposure and spermatozoa apoptosis. This study aimed to explore whether sperm protamine mediates the association of PAE exposure with spermatozoa apoptosis. We determined sperm protamine levels, 8 PAE metabolite concentrations in seminal plasma, and 3 spermatozoa apoptosis parameters among 111 men from an infertility clinic. The associations of PAEs as individual chemicals and mixtures with sperm protamine were determined. The mediating roles of protamine in the associations between PAEs and spermatozoa apoptosis parameters were examined by mediation analysis. After adjusting for confounders, we observed positive correlations between seminal plasma concentrations of mono(2-ethylhexyl) phthalate (MEHP) and sperm protamine-1 and protamine ratio. Estimates comparing highest vs. lowest quartiles of MEHP concentration were 4.65% (95% CI: 1.47%, 7.82%) for protamine-1 and 25.86% (95% CI: 3.05%, 53.73%) for protamine ratio. The quantile g-computation models showed that the adjusted protamine-1 per quartile increase in PAE mixture was 9.42% (95% CI: 1.00, 20.92) with MEHP being the major contributor. Although the joint association between PAE mixture and protamine ratio was negligible, MEHP was still identified as the main contributor. Furthermore, we found that protamine-2 and protamine ratio levels in the highest quartiles exhibited a decrease of 43.45% (95% CI: 60.54%, -19.75%) and an increase of 122.55% (95% CI: 60.00%, 209.57%) in Annexin V⁺/PI^- spermatozoa relative to the lowest quartiles, respectively. Mediation analysis revealed that protamine ratio significantly mediated 55.6% of the association between MEHP and Annexin V⁺/PI^- spermatozoa elevation (5.13%; 95% CI: 0.04%, 10.52%). Our findings provided evidence that human exposure to PAEs was associated with increased protamine levels which may mediate the process of spermatozoa apoptosis.

Anaphylaxis to Excipients in Current Clinical Practice: Evaluation and Management

Excipients are the inactive ingredients in a drug or product that help to stabilize, preserve, or enhance the pharmacokinetics and bioavailability of the active ingredients. Excipient allergy is rare and hence often missed or misdiagnosed due to lack of awareness of the need to carefully review all drug ingredients. For the patient, excipient allergy can be frightening and potentially disruptive to health care delivery. This narrative review provides a clinically oriented, international, collaborative perspective on excipient allergy testing, management of future health care safety, limitations in our testing modalities, and barriers to optimal care.

Cooperating minimalist nanovaccine with PD-1 blockade for effective and feasible cancer immunotherapy

•

Facile antigen/adjuvant co-loaded nanovaccine made by convenient green preparation.

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The immunological activity of the antigen and adjuvant was maximally preserved.

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The minimalist nanovaccine had excellent stability and antitumor immune activation.

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Nanovaccine combined with PD-1 antibody synergistically enhanced therapy outcome.

•

Good practicability for expanding clinical translation and personalized therapy.

Introduction

Tumor vaccine has been a research boom for cancer immunotherapy, while its therapeutic outcome is severely depressed by the vulnerable in vivo delivery efficiency. Moreover, tumor immune escape is also another intractable issue, which has badly whittled down the therapeutic efficiency.

Objectives

Our study aims to solve the above dilemmas by cooperating minimalist nanovaccine with PD-1 blockade for effective and feasible cancer immunotherapy.

Methods

The minimalist antigen and adjuvant co-delivery nanovaccine was developed by employing natural polycationic protamine (PRT) to carry the electronegative ovalbumin (OVA) antigen and unmethylated Cytosine-phosphorothioate-Guanine (CpG) adjuvant via convenient chemical bench-free “green” preparation without chemical-synthesis and no organic solvent was required, which could preserve the immunological activities of the antigens and adjuvants. On that basis, PD-1 antibody (aPD-1) was utilized to block the tumor immune escape and cooperate with the nanovaccine by maintaining the tumoricidal-activity of the vaccine-induced T cells.

Results

Benefited from the polycationic PRT, the facile PRT/CpG/OVA nanovaccine displayed satisfactory delivery performance, involving enhanced cellular uptake in dendritic cells (DCs), realizable endosomal escape and promoted stimulation for DCs’ maturation. These features would be helpful for the antitumor immunotherapeutic efficiency of the nanovaccine. Furthermore, the cooperation of the nanovaccine with aPD-1 synergistically improved the immunotherapy outcome, profiting by the cooperation of the “T cell induction” competency of the nanovaccine and the “T cell maintenance” function of the aPD-1.

Conclusion

This study will provide new concepts for the design and construction of facile nanovaccines, and contribute valuable scientific basis for cancer immunotherapy.

Protamine-Induced Coronary Graft Thrombosis: A Review

Perioperative myocardial infarction is a serious complication affecting a significant portion of patients undergoing coronary artery bypass graft surgery. This may arise due to coronary graft thrombosis, a rare but potentially fatal phenomenon associated with both congenital and acquired risk factors. Multiple case reports implicate the role of protamine in the development of such thromboses. The role of protamine in facilitating the regulation of hemostasis by reversing the anticoagulant effects of heparin in patients undergoing cardiopulmonary bypass is well-recognized. However, discussion of its potential contribution to coronary graft thrombosis and mechanisms by which this may occur is lacking. Furthermore, its narrow therapeutic index and side effect profile are such that its appropriateness as a universal reversal agent to heparin requires reconsideration. This article reviews the current body of evidence regarding the use of protamine in cardiac surgery and the limited case reports pertaining to its potential role in the pathophysiology of coronary graft thrombosis.

Functional differences between protamine preparations for the transfection of mRNA

Protamine is a natural cationic peptide mixture used as a drug for the neutralization of heparin and in formulations of slow-release insulin. In addition, Protamine can be used for the stabilization and delivery of nucleic acids (antisense, small interfering RNA (siRNA), immunostimulatory nucleic acids, plasmid DNA, or messenger RNA) and is therefore included in several compositions that are in clinical development. Notably, when mixed with RNA, protamine spontaneously generates particles in the size range of 20-1000 nm depending on the formulation conditions (concentration of the reagents, ratio, and presence of salts). These particles are being used for vaccination and immuno-stimulation. Several grades of protamine are available, and we compared them in the context of complex formation with messenger RNA (mRNA). We found that the different available protamine preparations largely vary in their composition and capacity to transfect mRNA. Our data point to the source of protamine as an important parameter for the production of therapeutic protamine-based complexes.

A guanidinium-rich polymer as a new universal bioreceptor for multiplex detection of bacteria from environmental samples

Protamine, a guanidinium rich polymer, is proposed as a universal bioreceptor for bacteria, towards rapid and handheld bacteria detection from complex environmental water samples without the need for specific antibodies or primers. Escherichia coli K12, Salmonella Typhimurium, and Staphylococcus aureus (MSSA) were assayed, representing gram-negative, gram-positive, rod- and round-shaped bacteria. Samples and the protamine conjugated fluorescent particles were sequentially loaded to the paper microfluidic chips and flowed through the channels spontaneously via capillary action. The particles were aggregated via protamine-bacteria membrane interactions and unbound particles were rinsed via capillary action. A low-cost smartphone fluorescence microscope was designed, fabricated, and imaged the paper channels. A unique image processing algorithm isolated only the aggregated particles to detect all three bacteria (p < 0.05) with a detection limit of 10¹-10² CFU/mL. Protamine did not induce any particle aggregation with a model protein, algae, and virus. Successful bacteria detection was also demonstrated with environmental field water samples. Total assay time was < 10 min with neither extraction nor enrichment steps. In summary, a guanidinium-rich polymer showed a promise as a universal bioreceptor for bacteria and can be used on a paper microfluidic chip and smartphone quantification towards rapid and handheld detection.

PROTAMINE TEST DOSE: IMPACT ON ACTIVATED CLOTTING TIME AND CIRCUIT INTEGRITY

BACKGROUND

Recurrent observation of clot in the cardiopulmonary bypass circuit following the administration of a Protamine Test Dose (PTD) prompted concern into the effects of PTDs on patient activated clotting times (ACT).

METHODS

Data was prospectively collected on 120 cardiopulmonary bypass patients undergoing a variety of cardiac surgeries from July to October, 2018. ACTs were documented prior to cardiopulmonary bypass termination, post PTD, and post protamine full dose. Statistical analysis was completed using a paired t-test.

RESULTS

The average PTD was calculated to be 36+21 mg or 11+7% of the full protamine dose of 367+153 mg. This "test" dose ranged from 1% to 67% of full dose depending upon the anesthetist. Post PTD ACTs were widely variable. On average, there was a 40+25% drop from last ACT on cardiopulmonary bypass (650+155 sec) to the ACT post PTD (376+153 sec) p<0.0001. In fact, 81+5% of the patient's post PTD ACTs fell below our institutional ACT standard of 480 seconds for safe cardiopulmonary bypass initiation.

CONCLUSIONS

Regardless of the protamine test dosage, there is no reliable way to predict how a patient's ACT will respond to a protamine test dose. Clot formation and circuit integrity is at risk when pump suction devices are continuously in use during PTD administration. Therefore, we strongly recommend that the direct recovery of mediastinal shed blood into the pump circuit be discontinued before any amount of protamine is administered to the patient.

Importin-9 regulates chromosome segregation and packaging in Drosophila germ cells

Germ cells undergo distinct nuclear processes as they differentiate into gametes. Although these events must be coordinated to ensure proper maturation, the stage-specific transport of proteins in and out of germ cell nuclei remains incompletely understood. Our efforts to genetically characterize Drosophila genes that exhibit enriched expression in germ cells led to the finding that loss of the highly conserved Importin β/karyopherin family member Importin-9 (Ipo9, herein referring to Ranbp9) results in female and male sterility. Immunofluorescence and fluorescent in situ hybridization revealed that Ipo9KO mutants display chromosome condensation and segregation defects during meiosis. In addition, Ipo9KO mutant males form abnormally structured sperm and fail to properly exchange histones for protamines. Ipo9 physically interacts with proteasome proteins, and Ipo9 mutant males exhibit disruption of the nuclear localization of several proteasome components. Thus, Ipo9 coordinates the nuclear import of functionally related factors necessary for the completion of gametogenesis. This article has an associated First Person interview with the first author of the paper.

The Treatment Effect of Protamine on Severe Coagulopathy in Epstein-Barr Virus-Associated Hemophagocytic Lymphohistiocytosis: Case Reports and Literature Review

Hemophagocytic lymphohistiocytosis (HLH) is a rare and life-threatening disease, which is characterized by severe systemic inflammation with cytokine storm as well as histologic evidence of hemophagocytosis. Besides, coagulopathy and hemorrhages are two common severe complications in HLH patients. Recent literatures indicate that Epstein-Barr virus (EBV) infection is one of the important triggers for the disease. In the study, we present three cases of EBV related HLH (EBV-HLH) with coagulopathy in patients with distinct backgrounds. Case 1 is a 45-year-old female diagnosed with EBV associated NK/T cell lymphoproliferative disorder (EBV-T/NK-LPD) and EBV-HLH. Case 2 is a 17-year-old male with a diagnosis of EBV-T-LPD and EBV-HLH. Case 3 is a 51-year-old male and also diagnosed with EBV-T-LPD and EBV-HLH. All cases were given with treatment with HLH-94 protocol, and the symptoms of the three patients improved. Furthermore, during the treatment, protamine, which has not been reported in the literature previously, was given to the three cases with EBV-HLH, and our results showed that after treatment with protamine, the coagulopathy and bleedings in these patients were improved rapidly. Unfortunately, the three patients relapsed soon and died despite intensive treatment. However, these cases suggest that protamine may serve as a potential treatment option for coagulation associated with EBV-HLH. Besides, the study helps us improve the understanding of the EBV-HLH related coagulation disorders, and provide a potential strategy for future treatment of the disease.

Ulinastatin attenuates protamine-induced cardiotoxicity in rats by inhibiting tumor necrosis factor alpha

Protamine causes cardiac depression, which may be mediated by tumor necrosis factor alpha (TNF-α). Ulinastatin, a human urinary protease inhibitor, inhibits TNF-α. Here, we aimed to investigate whether ulinastatin prevented protamine-induced myocardial depression by inhibiting TNF-α. Rat hearts were perfused using a Langendorff system, and three protocols were followed. Protocol 1: The hearts were divided into saline, ulinastatin-low, and ulinastatin-high groups. Protamine was administered to each group, and myocardial contractility was the primary outcome. Protocol 2: The hearts were allotted to saline or ulinastatin group. Protamine was administered to each group. TNF-α expression in the coronary effluent and myocardial tissue was measured. Protocol 3: The hearts were allotted to saline and ulinastatin groups. Recombinant rat-TNF-α was administered to each group. Protamine alone reduced the maximum left ventricular pressure derivative (LV dP/dt max) by 45 ± 4%. In contrast, the reduction in LV dP/dt max was 4 ± 3% in the ulinastatin-high group. Compared with that in the saline group, the increase in TNF-α in the coronary effluent was attenuated in the ulinastatin group. Recombinant TNF-α alone reduced LV dP/dt max (- 21 ± 14%). In contrast, when TNF-α was added in the presence of ulinastatin, the decrease in LV dP/dt max was prevented significantly (- 3 ± 8%). We showed, for the first time, that ulinastatin protected against protamine-induced myocardial damage, both by inhibiting TNF-α synthesis and by directly preventing the cardiodepressant action of TNF-α.

Sperm chromatin protamination influences embryo development in unsexed and sexed bull semen

Sex selection through sperm sorting offers advantages in regards selection pressure in high-producing livestock. However, the sex-sorting process results in sperm membrane and DNA damage that ultimately decrease fertility. We hypothesized that given the role of protamines in DNA packaging, protamine deficiency could account, at least partially, for the DNA damage observed following sperm sex sorting. To test this, we compared protamine status between unsexed and sexed spermatozoa from two bulls using the fluorochrome chromomycin A3 (CMA3) and flow cytometry. Then, we assessed embryo development following in vitro fertilization (IVF) using the same sperm treatments. Overall, sperm protamination was not different between sexed and unsexed semen. However, one of the two bulls displayed higher rates of protamine deficiency for both unsexed and sexed semen (P < 0.05). Moreover, unsexed semen from this bull yielded lower blastocyst (P < 0.05) and blastocyst hatching rates than unsexed sperm from the other bull. CMA3-positive staining was negatively correlated with cleavage (R2 85.1, P = 0.003) and blastocyst hatching (R2 87.6, P = 0.006) rates in unsexed semen. In conclusion, while the sex-sorting process had no effect on sperm protamine content, we observed a bull effect for sperm protamination, which correlated to embryo development rates following IVF.

Integration of fluorescent polydopamine nanoparticles on protamine for simple and sensitive trypsin assay

As an important protease, trypsin (TRY) has been identified as a key indicator of various diseases. A simple and sensitive strategy for TRY detection by using an environment-friendly biosafe probe is significant. Herein, we introduced negatively charged fluorescent polydopamine nanoparticles (PDNPs) with 4.8 nm diameter obtained through a controllable method as an effective probe for TRY. PDNPs exhibited excellent fluorescence property but integrated with protamine (Pro) to form an aggregation-caused quenching system via a static quenching mechanism. The quenching mechanism of Pro to PDNPs revealed the significant effect of the surface charge, functional groups, and appropriate size of PDNPs on quenching process. Given the specific hydrolysis of Pro by TRY, PDNPs were released from the quenching integration of PDNPs and Pro (PDNPs-Pro) and recovered their fluorescence. Thus, a fluorescence sensor for TRY with a linear range of 0.01 and 0.1 μg/mL and a detection limit of 6.7 ng/mL was developed without the disturbing from other proteases. Compared with other TRY assays, the biosensor based on PDNPs-Pro has the advantages of simple operation, environmental friendliness, and high sensitivity. This specific controlled-synthesis PDNPs would open up a new window for the extended application of fluorescent nanomaterials in biomedicine based on fluorescence changes induced by biological interaction.

Label-free exonuclease I-assisted signal amplification colorimetric sensor for highly sensitive detection of kanamycin

A label-free colorimetric method based on exonuclease I (Exo I)-assisted signal amplification with protamine as a medium was developed for analysis of kanamycin. In this study, a double-stranded DNA (dsDNA) probe was tailored by manipulating an aptamer and its complementary DNA (cDNA) ensuring detection of target with high selectivity and excellent sensitivity. Herein, protamine could not only combine with negatively charged gold nanoparticles but also interaction with polyanion DNA. Upon addition of target kanamycin, the target-aptamer complex was formed and the cDNA was released. Thus, both aptamer and cDNA could be digested by Exo I, and the captured kanamycin was liberated for triggering target recycling and signal amplification. Under optimized conditions, the proposed colorimetric method realized a low detection limit of 2.8 × 10^-14 M along with a wide linear range plus excellent selectivity. Our strategy exhibited enormous potentials for fabricate various kinds of biosensors based on target-induced aptamer configuration changes.

Vitamin E can promote spermatogenesis by regulating the expression of proteins associated with the plasma membranes and protamine biosynthesis

Vitamin E is generally believed to promote the production of ovine sperm mainly through its antioxidant effect. Our previous studies have shown that some non-antioxidant genes may also be key in mediating this process. The objective of this study was to identify key candidate proteins that were differentially expressed in response to a treatment with Vitamin E. Prepubertal ovine testicular cells were isolated and divided into two groups. They were either treated with 800 μM Vitamin E (based on our previous results) or used as a non-treated control. After 24 h, all the cells were harvested for proteomic analysis. We found 115 differentially expressed proteins, 4 of which were up-regulated and 111 were down-regulated. A GO term enrichment analysis identified 127 Biological Process, 63 Cell Component and 26 Molecular Function terms that were enriched. Within those terms, 13, 11 and 26 terms were significantly enriched, respectively. Terms related to membrane and enzyme activity including the inner acrosomal membrane, signal peptidase complex, cysteine-type endopeptidase activity, etc., were also markedly enriched, while none of the KEGG pathways were enriched. We found that many of the differentially expressed proteins, such as CD46 (membrane cofactor protein), FLNA (Filamin A), DYSF (Dysferlin), IFT20 (Intraflagellar transport 20), SPCS1 (Signal peptidase complex subunit 1) and SPCS3 (Signal peptidase complex subunit 3) were related to the acrosomal and plasma membranes. A parallel reaction monitoring (PRM) analysis verified that Vitamin E improved spermatogenesis by regulating the expression of FLNA, SPCS3, YBX3 and RARS, proteins that are associated with the plasma membranes and protamine biosynthesis of the spermatozoa.

Paternal epigenetics: Mammalian sperm provide much more than DNA at fertilization

The spermatozoon is a highly differentiated cell with unique characteristics: it is mobile, thanks to its flagellum, and is very compact. The sperm cytoplasm is extremely reduced, containing no ribosomes, and therefore does not allow translation, and its nucleus contains very closed chromatin, preventing transcription. This DNA compaction is linked to the loss of nucleosomes and the replacement of histones by protamines. Based on these characteristics, sperm was considered to simply deliver paternal DNA to the oocyte. However, some parts of the sperm DNA remain organized in a nucleosomal format, and bear epigenetic information. In addition, the nucleus and the cytoplasm contain a multitude of RNAs of different types, including non-coding RNAs (ncRNAs) which also carry epigenetic information. For a long time, these RNAs were considered residues of spermatogenesis. After briefly describing the mechanisms of compaction of sperm DNA, we focus this review on the origin and function of the different ncRNAs. We present studies demonstrating the importance of these RNAs in embryonic development and transgenerational adaptation to stress. We also look at other epigenetic marks, such as DNA methylation or post-translational modifications of histones, and show that they are sensitive to environmental stress and transmissible to offspring. The post-fertilization role of certain sperm-borne proteins is also discussed.

The study investigating the determination of protamine in seminal plasma from azoospermic donors: Suggestion of new methods to diagnose obstructive azoospermia, and to capture childbearing sperm for testicular sperm extraction (TESE) and insemination sperm injection (ICSI)

We analyzed seminal plasma of 88 normozoospermic, 40 oligozoospermic and 32 azoospermic donors. During this study, we focus to record the protamine concentration in the seminal plasma of azoospermic donors. The seminal protamine concentrations were found to be 19.6-62.8 IU/ml in normozoospermic donors; 25.4-100.8 IU/ml in oligozoospermic donors; and, most notably, 23.7-219.4 IU/ml in azoospermic donors. These results indicate that, based on seminal plasma protamine concentrations, even azoospermic donors were able to produce as much sperm as normo- and/or oligozoospermic donors. Using statistical analyses, significant differences were found between azoospermic and normozoospermic donors (p = 0.0018). Protamine content was found to be a direct marker for the presence of sperm. The data from this study provided evidence for a new therapeutic approach for testicular varicose veins, which are found in obstructive or non-obstructive azoospermia. High seminal protamine concentrations indicated the future possibility of acquiring childbearing sperm for insemination sperm injection (ICSI) and testicular sperm extraction (TESE), even with azoospermic donors. Given these results, we also suggest a new cut-off value for acquisition of childbearing sperm in selection for ICSI.

Fluorescence detection of protamine, heparin and heparinase II based on a novel AIE molecule with four carboxyl

In this research, a new DSA (Distyryl-anthracene) derivative with four carboxyl groups was designed and synthesized. This molecule exhibits aggregation-induced emission property (AIE). With the AIE character, a convenient and sensitive fluorescent probe for the detection of protamine, heparin and heparinase has been developed. The protamine can directly induce the aggregation of probe, which caused by electrostatic attraction. In this way, the turn-on detection of protamine is achieved, and the detection limit is as low as 30 ng mL^-1. When heparin appears, the probes will be redisperse in solution, which causes a decrease in fluorescence intensity. Besides, this method also shows good selectivity and sensitivity, and the linear range of heparin is from 0.08 to 8 μg mL^-1 with detection limit of 37 ng mL^-1. After hydrolyzing heparin by heparinase, the probes rebind with protamine and the fluorescence enhance. The fluorescence enhancement was linearly related to the concentration of heparinase in the range of 0.02-2.0 μg mL^-1 and detection limit as low as 143.7 ng mL^-1. In addition, the results exhibited that the recovery percentage of heparinase in bovine samples reached to 96-101%.

An anionic polyelectrolyte induced aggregate assembly of Thioflavin-T: A prospective platform for Protamine sensing

Protamine, a polycation, is biologically and medically relevant protein. Protamine exhibits a wide array of functions in biological processes like gene transfer, tissue and organogenesis, cell reproduction, etc. Medically, Protamine is the only clinically approved antidote for Heparin and is routinely used in various surgical interventions, and hence controlling Protamine dosing in patients is very crucial. Taking into account the medical significance of Protamine, designing simple, reliable and sensitive fluorescence sensors is highly desirable. In this work, we propose one such sensitive and reliable fluorescent sensor which is based on a template of dye-polyelectrolyte assembly constituting a molecular rotor dye, Thioflavin-T and an anionic synthetic polyelectrolyte, polystyrene sulfonate. The addition of Protamine, prompts drastic modulations in spectral features of dye-polyelectrolyte assembly which enables sensitive detection of Protamine in aqueous solution. Apart from sensitive detection, our sensing platform aids in highly selective sensing of Protamine compared to other proteins. Moreover, our sensor system is constructed on label-free, inexpensive, commercially available molecules posing as an advantage over other sensor systems which involve laborious synthesis protocols. Most importantly, our sensor template is able to sense Protamine in diluted serum sample, indicating the potential practical utility of our sensor system.

Factors influencing activated clotting time following heparin administration for the initiation of cardiopulmonary bypass

OBJECTIVES

Initiation of cardiopulmonary bypass (CPB) for open-heart surgery requires that heparin be administered and reach an adequate value of activated clotting time (ACT). We previously introduced a new heparin formula that considered the preoperative ACT. In this study, we determined other factors affecting ACT.

METHODS

Adult patients who underwent cardiac surgery using CPB were divided into two groups according to their ACT value after the initial administration of heparin during surgery. ACT above 450 s was defined as "Reach", and this group was compared to the "Short" group with ACT below 450 s.

RESULTS

The Reach and Short groups included 334 (64.7%) and 182 (35.3%) cases, respectively. Univariate analysis indicated that preoperative heparin use, age ≥ 80 years, New York Heart Association classification 4, white blood cell counts above the higher limit, hematocrit below the lower limit, platelet cell counts below the lower limit, low albumin levels, moderate renal dysfunction, high C-reactive protein levels, high brain natriuretic peptide levels, and moderate deterioration of left ventricular ejection fraction were associated with the effects of heparin. Multivariate analysis revealed that age ≥ 80 years (odds ratio [OR] 2.53, 95% confidence interval [95%CI] 1.41-5.24), New York Heart Association classification 4 (OR = 4.44, 95%CI 1.59-15.35), and platelet count below the lower limit (OR 0.37, 95%CI 0.31-0.85) were associated with the effects of heparin.

CONCLUSION

Old age, heart failure, and lower platelet counts affected heparin activity. The dose of heparin should be considered in those patients to reach the target ACT.

Protamine use in transfemoral carotid artery stenting is not associated with an increased risk of thromboembolic events

BACKGROUND

Protamine use in carotid endarterectomy has been shown to be associated with fewer perioperative bleeding complications without higher rates of thromboembolic events. However, the effect of protamine use on complications after transfemoral carotid artery stenting (CAS) is unclear, and concerns remain about thromboembolic events.

METHODS

A retrospective review was performed for patients undergoing transfemoral CAS in the Vascular Quality Initiative from March 2005 to December 2018. We assessed in-hospital outcomes using propensity score-matched cohorts of patients who did and did not receive protamine. The primary outcome was in-hospital stroke or death. Secondary outcomes included bleeding complications, stroke, death, transient ischemic attack, myocardial infarction, and congestive heart failure exacerbation. Bleeding complications were categorized as bleeding resulting in intervention or blood transfusions.

RESULTS

Of the 17,429 patients undergoing transfemoral CAS, 2697 (15%) patients received protamine. We created 2300 propensity score-matched pairs of patients who did and did not receive protamine. There were no statistically significant differences in stroke or death between the two cohorts (protamine, 2.5%; no protamine, 2.9%; relative risk [RR], 0.85; 95% confidence interval [CI], 0.60-1.21; P = .37). Protamine use was not associated with statistically significant differences in perioperative bleeding complications resulting in interventional treatment (0.9% vs 0.5%; RR, 2.10; 95% CI, 0.99-4.46; P = .05) or blood transfusion (1.2% vs 1.2%; RR, 0.92; 95% CI, 0.53-1.61; P = .78). There were also no statistically significant differences for the individual outcomes of stroke (1.8% vs 2.3%; RR, 0.78; 95% CI, 0.52-1.16; P = .22), death (0.9% vs 0.8%; RR, 1.17; 95% CI, 0.62-2.19; P = .63), transient ischemic attack (1.4% vs 1.3%; RR, 1.10; 95% CI, 0.67-1.82; P = .70), myocardial infarction (0.5% vs 0.4%; RR, 1.20; 95% CI, 0.52-2.78; P = .67), or heart failure exacerbation (1.0% vs 0.9%; RR, 1.05; 95% CI, 0.58-1.90; P = .88). Protamine use in patients presenting with symptomatic carotid stenosis was associated with lower risk of stroke or death (3.0% vs 4.3%; RR, 0.69; 95% CI, 0.47-0.998; P = .048), whereas there were no statistically significant differences in stroke or death with protamine use in asymptomatic patients (1.6% vs 1.0%; RR, 1.63; 95% CI, 0.67-3.92; P = .28).

CONCLUSIONS

Heparin reversal with protamine after transfemoral CAS is not associated with an increased risk of thromboembolic events, and its use in symptomatic carotid disease is associated with a lower risk of stroke or death.

Protamine sulfate use during tibial bypass does not appear to increase thrombotic events or affect short-term graft patency

OBJECTIVES

While the use of protamine sulfate as a heparin reversal agent has been extensively reviewed in patients undergoing carotid endarterectomy and coronary artery bypass grafting, there is a lack of literature on protamine's effects on lower extremity bypasses. The purpose of this study was to determine the risk of protamine sulfate dosing after tibial bypass on thrombotic or bleeding events, including early bypass failure.

METHODS

We performed a retrospective review of our institutional database for patients undergoing primary distal peripheral bypass from January 2009 through December 2015 (contralateral bypass was considered to be a new primary bypass). Primary endpoints include composite thrombotic events (myocardial infarction, stroke, amputation at 30 days and patency less than 30 days) and composite bleeding events (bleeding or transfusion).

RESULTS

A total of 152 tibial or peroneal bypasses in 136 patients with critical limb ischemia were identified. Of these, 78 (57.4%) patients received protamine sulfate intraoperatively and 58 (42.6%) did not. There were no differences in composite thrombotic or hemorrhagic outcomes. Protamine use had no effect on the rates of perioperative MI (9.0% versus 3.5%, p = 0.20), stroke (1.3% versus 1.7%, p = 0.83), or perioperative mortality (5.1% versus 3.5%, p = 0.64). There was no significant difference in composite post-operative bleeding events (20.7% versus 14.1%, p = 0.31) or composite thrombotic events (17.2% versus 18.0%, p = 0.91). Patients who received protamine undergoing bypass with non-autogenous conduit had significantly higher-recorded median operative blood loss (250 mL versus 150 mL, p = 0.0097) and median procedure lengths (265 min versus 201 min, p = 0.0229). No difference in 30-day amputation-free survival was noted (91.0% versus 91.4%, p = 0.94). Follow-up Kaplan-Meier estimation did not demonstrate a difference in 30-day patency (91.7% versus 88.5%, p = 0.52).

CONCLUSIONS

Heparin reversal with protamine sulfate after tibial or peroneal bypass grafting is not associated with higher cardiovascular morbidity, bypass thrombosis, amputation, or mortality. Additionally, there was no statistically significant difference in post-operative bleeding or thrombosis complications for patients who did not receive protamine, although the findings are suggestive of a potential difference in a more adequately powered study. Our results suggest that protamine sulfate is safe for intraoperative use without increased risk of thrombotic complications or early tibial bypass graft failure.

Determination of antimicrobial effect of protamine by transmission electron microscopy and SDS PAGE on Pseudomonas aeruginosa isolates from diabetic foot infection

Objective(s):

Diabetic foot infection is one of the major complications of diabetes leading to lower limb amputations. Isolation and identification of bacteria causing diabetic foot infection, determination of antibiotic resistance, antimicrobial potential of protamine by electron microscopy and SDS-PAGE analysis, arethe aims of this study.

Materials and Methods:

285 pus samples from diabetic foot infection patients were collected from different hospitals of Karachi and Capital Health Hospital, Halifax, Canada. Clinical history of each patient was recorded. Bacterial isolates were cultured on appropriate media; identification was done by morphology, cultural and biochemical tests. Effect of protamine against multi drug resistant strains of Pseudomona aeruginosa was checked by minimum inhibitory concentration in 96 well micro-titer plates. The isolates were grown in bactericidal concentration of protamine on plates to isolate mutants. Effect of protamine on protein expression was checked by SDS- PAGE and ultra-structural morphological changes by transmission electron microscopy.

Results:

Results indicated prevalence of foot infection as 92% in diabetic patients. Major bacterial isolates were Staphylococcus aureus 65 (23%), P. aeruginosa 80 (28.1%), Klebsiella spp. 37 (13%), Proteus mirabilis 79 (27.7%), and Escherichia coli 24 (12%). These isolates were highly resistant to different antibiotics. MIC value of protamine was 500 µg/ml against P. aeruginosa. SDS-PAGE analysis revealed that protamine can suppress expression of various virulence proteins and electron micrographs indicated condensation of cytoplasm and accumulation of protamine in cytoplasm without damaging the cell membrane.

Conclusion:

P. aeruginosa and S. aureus were the major isolates expressing multi-drug resistance and protamine sulfate represented good antimicrobial potential.

Entropy based analysis of vertebrate sperm protamines sequences: evidence of potential dityrosine and cysteine-tyrosine cross-linking in sperm protamines

BACKGROUND

Spermatogenesis is the process by which germ cells develop into spermatozoa in the testis. Sperm protamines are small, arginine-rich nuclear proteins which replace somatic histones during spermatogenesis, allowing a hypercondensed DNA state that leads to a smaller nucleus and facilitating sperm head formation. In eutherian mammals, the protamine-DNA complex is achieved through a combination of intra- and intermolecular cysteine cross-linking and possibly histidine-cysteine zinc ion binding. Most metatherian sperm protamines lack cysteine but perform the same function. This lack of dicysteine cross-linking has made the mechanism behind metatherian protamines folding unclear.

RESULTS

Protamine sequences from UniProt's databases were pulled down and sorted into homologous groups. Multiple sequence alignments were then generated and a gap weighted relative entropy score calculated for each position. For the eutherian alignments, the cysteine containing positions were the most highly conserved. For the metatherian alignment, the tyrosine containing positions were the most highly conserved and corresponded to the cysteine positions in the eutherian alignment.

CONCLUSIONS

High conservation indicates likely functionally/structurally important residues at these positions in the metatherian protamines and the correspondence with cysteine positions within the eutherian alignment implies a similarity in function. One possible explanation is that the metatherian protamine structure relies upon dityrosine cross-linking between these highly conserved tyrosines. Also, the human protamine P1 sequence has a tyrosine substitution in a position expecting eutherian dicysteine cross-linking. Similarly, some members of the metatherian Planigales genus contain cysteine substitutions in positions expecting plausible metatherian dityrosine cross-linking. Rare cysteine-tyrosine cross-linking could explain both observations.

A heparin-modified palladium nanozyme for photometric determination of protamine

Heparin was employed as the stabilizing agent in the synthesis of peroxidase-mimicking Pd nanoparticles. The heparin-capped Pd nanozyme can act as both the signal amplifier and the selective binder of protamine. The most efficient nanozyme with the mean size of 3.5 nm consists of 70.8% metallic Pd⁰ and 29.2% Pd²⁺ species. Enzyme kinetic studies show that the K_m values are 0.036 mM for 3,3',5,5'-tetramethylbenzidine and 78 mM for H₂O₂. Protamine shows strong affinity to the heparin-capped Pd nanozyme, and induces an apparent aggregation of the nanoparticles. This results in a significant inhibition of the peroxidase-mimicking activities. Hence, the oxidation of TMB by H₂O₂ to a blue product with a maximum absorption at 652 nm is suppressed. Based on this finding, a photometric assay is developed for the determination of protamine. The linear response is in the concentration range 0.02 ~ 0.8 μg mL^-1, and the limit of detection is 0.014 μg mL^-1. This assay presents high selectivity toward other biological substances. Graphical abstract Highly active and selective Pd nanozyme was synthesized through adopting heparin as the capping agent for quantitative determination of protamine.

The investigation of synergistic activity of protamine with conventional antimicrobial agents against oral bacteria

In this study, we applied protamine, which is an antimicrobial peptide, to oral healthcare in combination with conventional antimicrobial agents. First, we explored the antimicrobial activity of protamine, with or without other antimicrobial agents, against Streptococcus mutans (S. mutans). Co-treatment with protamine and 3-methyl-4-isopropylphenol (IPMP) decreased the viability of S. mutans synergistically within 10 min. Interestingly, sodium fluoride (NaF) did not exhibit synergistic activity with protamine. Next, S. mutans and Streptococcus gordonii (S. gordonii) were co-treated with protamine and IPMP for 5 min to simulate tooth brushing. As a result, this co-treatment killed S. mutans faster than S. gordonii. Therefore, co-treatment with protamine and IPMP could be incorporated into oral healthcare products to prevent dental caries.

Determination of Colistin Resistance by Simple Disk Diffusion Test Using Modified Mueller-Hinton Agar

Background

Colistin has become a last-resort antibiotic for the management of multidrug-resistant gram-negative bacteria. The disk diffusion test is cheap and easy to perform but may be unreliable for colistin susceptibility testing due to poor diffusion of the large colistin molecule. An improved agar diffusion test would increase the reliability of colistin susceptibility testing. This study aimed to modify Muller-Hinton agar (MHA) to improve colistin diffusion in agar.

Methods

MHA was modified by reducing the agar concentration from 100% to 30% and supplementing with protamine. We tested 60 gram-negative clinical isolates of Pseudomonas aeruginosa (N=27) and Acinetobacter calcoaceticus-baumannii complex (N=33). Disk diffusion test results were interpreted based on minimum inhibitory concentrations determined by broth microdilution.

Results

The modified MHA yielded the best performance metrics, including 94.7% sensitivity, 100% specificity, and an area under the curve of 0.995 (95% confidence interval, 0.982–1.000), P<0.001, at a cut-off point of 13 mm.

Conclusions

A reduction of the agar concentration from 100% to 30% and the addition of protamine improved colistin diffusion in agar and allowed routine colistin susceptibility testing in a clinical microbiology laboratory, but should be handled with caution.

Novel Liposome Aggregate Platform (LAP) system for sustained retention of drugs in the posterior ocular segment following intravitreal injection

A novel Liposome Aggregate Platform (LAP) system for prolonged retention of drugs in the posterior eye segment after intravitreal injection (IVT) was developed and evaluated. Calcein, FITC-dextran-4000 (FD4) and Flurbiprofen (FLB), were encapsulated in negatively charged liposomes, and mixed with protamine to produce the LAP. The lipid/protamine ratio was fixed, in order to have a convenient aggregation rate permitting IVT injection and also a sustained release of liposome-entrapped molecules (in vitro) from LAP. In vitro release studies confirmed the potential of LAP system consisted of HPC/DPPG/Chol liposomes and protamine (at 1:1 w/w to lipid), to delay calcein, FD4 and FLB release, compared to free liposomes. In vivo studies demonstrated increased vitreous retention of liposomes and LAP for all molecules, compared to the corresponding solutions; however the retention of FD4 is similar for non-aggregated liposomes and LAP, and calcein retention is only slightly increased by LAP compared to liposomes. The later result may be connected with the visible ocular inflammation caused by both dyes; interestingly inflammation was moderately reduced when dyes were entrapped in liposomes and even more when in LAP. No visible inflammation was demonstrated for FLB, and the LAP system significantly increased the retention of FLB in the ocular tissues (compared to non-aggregated liposomes). Taking into account the capability of the novel LAP system to decrease inflammatory reactions towards calcein and FD4, and prolong the retention of FLB in ocular tissues, it is concluded that such systems, after further optimization, may be considered as promising effective and safe approaches for treatment of posterior segment ocular pathologies.

Influence of the age of the individual on the stability of boar sperm genetic material

Routine evaluation of the sperm of livestock animals involves detection of morphological abnormalities. However, most sperm defects that reduce fertilizing capacity are a result of anomalies in spermatogenesis. The aim of the study was to evaluate the effect of a boar's age on the stability of the genetic material of its sperm. The age of the boar was found to have a significant effect on sperm DNA stability and chromatin structure. The highest percentage of spermatozoa with DNA fragmentation was found in the oldest group of boars (0,61%), while the highest proportion of spermatozoa with abnormal histone retention (8,01%) and protamination (9,78%) was found in the youngest group of boars. Aniline blue (AB), chromomycin A3 (CMA3) and acridine orange (AO) staining should be routinely used in individuals used for artificial insemination especially young animals at the start of their exploitation for breeding, as well as older individuals with an age-related decrease in the stability of genetic material. Earlier diagnosis based on additional tests would allow for stricter selection and elimination of males with fertility disorders from breeding, to be replaced by breeders of full value. It was also demonstrated that all three staining methods mentioned above can be used in classical morphological analysis, because they clearly distinguish the sperm head from the background of the slide. Chromomycin staining clearly reveals the midpiece and thus can be used as a specific staining method for its evaluation. Staining with aniline blue is a fast and simple test whose result can be analysed under a light microscope. This staining technique can be recommended for use at insemination stations.