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International Journal For Parasitology.... May 2024Plasmodium falciparum aminoacyl tRNA synthetases (PfaaRSs) are potent antimalarial targets essential for proteome fidelity and overall parasite survival in every stage...
Plasmodium falciparum aminoacyl tRNA synthetases (PfaaRSs) are potent antimalarial targets essential for proteome fidelity and overall parasite survival in every stage of the parasite's life cycle. So far, some of these proteins have been singly targeted yielding inhibitor compounds that have been limited by incidences of resistance which can be overcome via pan-inhibition strategies. Hence, herein, for the first time, we report the identification and in vitro antiplasmodial validation of Mitomycin (MMC) as a probable pan-inhibitor of class 1a (arginyl(A)-, cysteinyl(C), isoleucyl(I)-, leucyl(L), methionyl(M), and valyl(V)-) PfaaRSs which hypothetically may underlie its previously reported activity on the ribosomal RNA to inhibit protein translation and biosynthesis. We combined multiple in silico structure-based discovery strategies that first helped identify functional and druggable sites that were preferentially targeted by the compound in each of the plasmodial proteins: Ins1-Ins2 domain in Pf-ARS; anticodon binding domain in Pf-CRS; CP1-editing domain in Pf-IRS and Pf-MRS; C-terminal domain in Pf-LRS; and CP-core region in Pf-VRS. Molecular dynamics studies further revealed that MMC allosterically induced changes in the global structures of each protein. Likewise, prominent structural perturbations were caused by the compound across the functional domains of the proteins. More so, MMC induced systematic alterations in the binding of the catalytic nucleotide and amino acid substrates which culminated in the loss of key interactions with key active site residues and ultimate reduction in the nucleotide-binding affinities across all proteins, as deduced from the binding energy calculations. These altogether confirmed that MMC uniformly disrupted the structure of the target proteins and essential substrates. Further, MMC demonstrated IC < 5 μM against the Dd2 and 3D7 strains of parasite making it a good starting point for malarial drug development. We believe that findings from our study will be important in the current search for highly effective multi-stage antimalarial drugs.
PubMed: 38805932
DOI: 10.1016/j.ijpddr.2024.100548 -
Cureus Apr 2024We present the case of a 27-year-old male who presented to our ophthalmology outpatient clinic with a pigmented lesion on the conjunctiva of his right eye. There was no...
We present the case of a 27-year-old male who presented to our ophthalmology outpatient clinic with a pigmented lesion on the conjunctiva of his right eye. There was no history of ocular trauma or familial ocular complaints, and a thorough evaluation revealed the patient's seropositive status for HIV for the past eight years. The presentation resembled a conjunctival pigmentary lesion, with typical features of ocular surface squamous neoplasia (OSSN) being absent and a demographic incongruent with typical OSSN cases as OSSN typically affects the elderly population. Given the patient's HIV status and the lesion's recent increase in size, a more aggressive treatment approach was warranted. Mass excisional biopsy surgery confirmed conjunctival intraepithelial neoplasia with one positive margin. Adjuvant treatment with mitomycin eye drops (0.04%) resulted in no lesion recurrence at the one-month follow-up. Conjunctival intraepithelial neoplasia can mimic pigmentary lesions in young HIV-positive patients with obvious signs of OSSN being absent. In such cases, the history of seropositivity should be sufficient to suspect it as OSSN and aggressive management measures should be adopted to get best possible outcomes.
PubMed: 38800191
DOI: 10.7759/cureus.58953 -
Journal of Personalized Medicine May 2024Chronic tympanic membrane perforation represents a prevalent otological condition, necessitating a reliable animal model for the validation and safety assessment of...
Chronic tympanic membrane perforation represents a prevalent otological condition, necessitating a reliable animal model for the validation and safety assessment of surgical techniques and materials employed in myringoplasty. This prospective study involved the establishment of chronic tympanic membrane perforation animal models in 16 chinchillas. A thermic myringotomy was conducted on the right ear (study group), followed by cold instrument myringotomy, coupled with the topical application of mitomycin C and dexamethasone solution on the left ear (control group). Results revealed that tympanic membrane perforations in the study group persisted for a minimum of 4 weeks in 93.7% of cases and extended to 12 weeks in 62.5% of the cases. In contrast, all tympanic membrane perforations in the control group were present at 4 weeks, with only 37.5% persisting after 12 weeks, although statistical tests did not find significant differences between the two groups (chi-square: -value = 0.157, Kruskal-Wallis: -value = 0.093, Mann-Whitney: -value = 0.121). The thermic myringotomy employed to induce chronic tympanic membrane perforation in animals demonstrated efficiency and sustainability. This model, characterized by stability and reproducibility, holds promise for future experimental applications in the field.
PubMed: 38793095
DOI: 10.3390/jpm14050513 -
Cancers May 2024Repeated transurethral bladder resections (TURBs) and instillation treatments in non-muscle invasive bladder cancer (NMIBC) might influence bladder function and,...
Repeated transurethral bladder resections (TURBs) and instillation treatments in non-muscle invasive bladder cancer (NMIBC) might influence bladder function and, therefore, quality of life. Bladder-related medication is a surrogate marker of compromised bladder function. The objective was to investigate whether TURBs and adjuvant instillation therapy are associated with the use of anticholinergics, β3-agonists, and cystitis-relevant antibiotics. We divided all Danish patients diagnosed with primary NMIBC during 2002-2017 registered in the Danish National Patient Registry (DNPR) based on TURB-load within the first five years from diagnosis (1 TURB, 2-4 TURBs, ≥5 TURBs). Instillation therapy with either mitomycin C (MMC) or bacillus Calmette-Guerin vaccine (BCG) was independent exposure (yes or no). We included 17,774 patients; 76% men, median age: 70 years (IQR: 63, 77). Patients exposed to ≥5 TURBs had a higher risk of using bladder-relaxing medication than patients exposed to 1 TURB, HR = 4.01 [3.33; 4.83], and higher risk of cystitis, HR = 2.27 [2.05; 2.51]. BCG-exposed patients had a higher risk of bladder-relaxing medication use compared to non-exposed, HR = 1.92 [1.69; 2.18], and a higher risk of cystitis, HR = 1.39 [1.31; 1.48]. Repeated TURBs have the highest impact on bladder function. Adjuvant instillation therapy is also associated with the use of bladder-related medication.
PubMed: 38792014
DOI: 10.3390/cancers16101936 -
Cancers May 2024Nephron sparing surgery (NSS) is considered for selected cases of upper tract urothelial carcinoma (UTUC) as it maintains renal function and avoids morbidity associated... (Review)
Review
Nephron sparing surgery (NSS) is considered for selected cases of upper tract urothelial carcinoma (UTUC) as it maintains renal function and avoids morbidity associated with radical nephroureterectomy (RNU). The appropriate selection of patients suitable for NSS without compromising oncological outcomes can sometimes be difficult, given the limitations of diagnostic modalities. Recurrence rates for UTUC can be as high as 36 to 54% after NSS. Intraluminal adjuvant therapy can be attempted following NSS to reduce recurrence, but delivery to the upper tract is more challenging than into the bladder. Bacillus Calmette-Guerin (BCG) and chemotherapy such as Mitomycin (MMC) have been administered via nephrostomy or ureteric catheter, which requires invasive/repeated instrumentation of the upper urinary tract. Drug delivery by reflux from bladder instillation along indwelling stents has also been tried but can potentially be unreliable. Recently, a gel formulation of mitomycin has been developed for the controlled exposure of the upper urinary tract to treatment over a number of hours. Drug-eluting stents to deliver chemotherapy to the upper urinary tract have been developed but have not yet entered clinical practice. Endoluminal phototherapy utilising an intravenous photosensitising agent is another novel approach that has recently been described. Intraluminal therapies may be beneficial in decreasing recurrence rates in UTUC, but currently have some limitations in their usage.
PubMed: 38792009
DOI: 10.3390/cancers16101931 -
Bioengineering (Basel, Switzerland) Apr 2024Excessive fibrosis and resultant poor control of intraocular pressure (IOP) reduce the efficacy of glaucoma surgeries. Historically, corticosteroids and anti-fibrotic... (Review)
Review
Excessive fibrosis and resultant poor control of intraocular pressure (IOP) reduce the efficacy of glaucoma surgeries. Historically, corticosteroids and anti-fibrotic agents, such as mitomycin C (MMC) and 5-fluorouracil (5-FU), have been used to mitigate post-surgical fibrosis, but these have unpredictable outcomes. Therefore, there is a need to develop novel treatments which provide increased effectiveness and specificity. This review aims to provide insight into the pathophysiology behind wound healing in glaucoma surgery, as well as the current and promising future wound healing agents that are less toxic and may provide better IOP control.
PubMed: 38790314
DOI: 10.3390/bioengineering11050446 -
Antibiotics (Basel, Switzerland) Apr 2024is a recently described staphylococcal species that is related to but lacks the staphyloxanthin operon. It is able to acquire both resistance markers such as the SCC...
is a recently described staphylococcal species that is related to but lacks the staphyloxanthin operon. It is able to acquire both resistance markers such as the SCC elements and mobile genetic elements carrying virulence-associated genes from . This includes those encoding the Panton-Valentine leukocidin (PVL), which is associated mainly with severe and/or recurrent staphylococcal skin and soft tissue infections. Here, we describe the genome sequences of two PVL-positive, -negative sequence type (ST) 2250 isolates from the United Arab Emirates in detail. The isolates were found in a dental clinic in the United Arab Emirates (UAE). Both were sequenced using Oxford Nanopore Technology (ONT). This demonstrated the presence of temperate bacteriophages in the staphylococcal genomes, including a PVL prophage. It was essentially identical to the published sequence of phiSa2wa_st78 (GenBank NC_055048), a PVL phage from an Australian clonal complex (CC) 88 isolate. Besides the PVL prophage, one isolate carried another prophage and the second isolate carried two additional prophages, whereby the region between these two prophages was inverted. This "flipped" region comprised about 1,083,000 bp, or more than a third of the strain's genome, and it included the PVL prophage. Prophages were induced by Mitomycin C treatment and subjected to transmission electron microscopy (TEM). This yielded, in accordance to the sequencing results, one or, respectively, two distinct populations of icosahedral phages. It also showed prolate phages which presumptively might be identified as the PVL phage. This observation highlights the significance bacteriophages have as agents of horizontal gene transfer as well as the need for monitoring emerging staphylococcal strains, especially in cosmopolitan settings such as the UAE.
PubMed: 38786130
DOI: 10.3390/antibiotics13050401 -
Ear, Nose, & Throat Journal May 2024Laryngeal keel insertion, mucosal suture, application of mitomycin-C (MMC), and staged operations are approaches to prevent the anterior glottic web, but there are...
Laryngeal keel insertion, mucosal suture, application of mitomycin-C (MMC), and staged operations are approaches to prevent the anterior glottic web, but there are limitations. Our study suggests a modified approach to prevent the formation of an anterior glottic web. This retrospective single-institution tertiary center study (N = 23) involved the simultaneous removal of bilateral vocal fold lesions with topical MMC application. If exudate was identified after 4 to 6 weeks, second laryngomicroscopic surgery (LMS) was performed to remove it with topical MMC application. Extent of anterior glottic web was measured as a percentage of the total length of the membranous vocal fold. After the initial surgery, 18 patients recovered without anterior web or fibrin exudate. Thick exudate was observed in 5 patients. After the second LMS, all patients showed improvement and did not develop anterior web. This modified method has been developed to prevent the anterior glottic web without complications.
PubMed: 38770943
DOI: 10.1177/01455613241255790 -
International Journal of Ophthalmology 2024To study the effect of mitomycin C (MMC) applied during transepithelial photorefractive keratectomy (TPRK) on the corneal endothelium one week (W1) and three months (M3)...
AIM
To study the effect of mitomycin C (MMC) applied during transepithelial photorefractive keratectomy (TPRK) on the corneal endothelium one week (W1) and three months (M3) after surgery and its determinants.
METHODS
In this two-armed cohort study conducted in 2022, eyes treated with MMC during TPRK (group 1) were compared with eyes not treated with MMC (group 2). The corneal endothelial cell (EC) count, EC density (ECD; cells/mm), average (µm), standard deviation (µm), coefficient of variation (CV%), EC, EC, and EC percentage of hexagonality were estimated at W1 and M3. The postoperative changes in the EC count in the two groups were compared and correlated with the other independent variables.
RESULTS
Group 1 had 26 eyes, and group 2 had 78 eyes. All TPRK indices were significantly higher for the eyes in group 1 than for those in group 2. The MMC usage was not a significant predictor of the change in ECD (=0.644), change in CV (=0.374), and change in the percentage of hexagonality of EC (=0.164) at W1. However, the use of MMC was a significant predictor of changes in CV (=0.014) and the change in the percentage of hexagonality of EC (=0.039) at M3. The duration of laser exposure and the size of the optical zone influenced the correlation of MMC use with the changes in EC indices, postoperatively.
CONCLUSION
The use of MMC doesn't affect ECD, CV, and percentage of hexagonality at W1 if other surgical indices are considered. At M3 after operating myopic eyes by TPRK, MMC significantly influence the CV and percentage of hexagonality. The duration of the laser application and the size of the optical zone should be considered when determining the effect of MMC on the EC indices.
PubMed: 38766343
DOI: 10.18240/ijo.2024.05.16 -
MBio May 2024A recent demonstration of synergy between a temperate phage and the antibiotic ciprofloxacin suggested a scalable approach to exploiting temperate phages in therapy,...
A recent demonstration of synergy between a temperate phage and the antibiotic ciprofloxacin suggested a scalable approach to exploiting temperate phages in therapy, termed temperate phage-antibiotic synergy, which specifically interacted with the lysis-lysogeny decision. To determine whether this would hold true across antibiotics, we challenged with the phage HK97 and a set of 13 antibiotics spanning seven classes. As expected, given the conserved induction pathway, we observed synergy with classes of drugs known to induce an SOS response: a sulfa drug, other quinolones, and mitomycin C. While some β-lactams exhibited synergy, this appeared to be traditional phage-antibiotic synergy, with no effect on the lysis-lysogeny decision. Curiously, we observed a potent synergy with antibiotics not known to induce the SOS response: protein synthesis inhibitors gentamicin, kanamycin, tetracycline, and azithromycin. The synergy results in an eightfold reduction in the effective minimum inhibitory concentration of gentamicin, complete eradication of the bacteria, and, when administered at sub-optimal doses, drastically decreases the frequency of lysogens emerging from the combined challenge. However, lysogens exhibit no increased sensitivity to the antibiotic; synergy was maintained in the absence of RecA; and the antibiotic reduced the initial frequency of lysogeny rather than selecting against formed lysogens. Our results confirm that SOS-inducing antibiotics broadly result in temperate-phage-specific synergy, but that other antibiotics can interact with temperate phages specifically and result in synergy. This is the first report of a means of chemically blocking entry into lysogeny, providing a new means for manipulating the key lysis-lysogeny decision.IMPORTANCEThe lysis-lysogeny decision is made by most bacterial viruses (bacteriophages, phages), determining whether to kill their host or go dormant within it. With over half of the bacteria containing phages waiting to wake, this is one of the most important behaviors in all of biology. These phages are also considered unusable for therapy because of this behavior. In this paper, we show that many antibiotics bias this behavior to "wake" the dormant phages, forcing them to kill their host, but some also prevent dormancy in the first place. These will be important tools to study this critical decision point and may enable the therapeutic use of these phages.
PubMed: 38757974
DOI: 10.1128/mbio.00504-24