Using a Novel, Subconjunctival, Sustained-Release Mitomycin C Formulation in a Rabbit Model of Filtration Surgery with Gel Stent Implantation

Purpose: To investigate gel stent implantation with and without intraoperative sustained-release mitomycin C (MMC SR) in a rabbit model for gel stent implantation, and to examine aqueous humor outflow (AHO) postimplantation. Methods: Four groups of rabbits were included. Group 1 was untreated (control). Groups 2, 3, and 4 received the gel stent without MMC, with MMC solution (subconjunctival injection), and with MMC SR (subconjunctival injection), respectively. Intraocular pressure (IOP) and AHO were assessed via tonometry and indocyanine green-based angiography, respectively. The main efficacy measure was change in IOP from baseline. Results: Following gel stent implantation, Groups 2, 3, and 4 maintained ≥20% IOP reduction (response) for a median duration of 1 week, 6.5 weeks, and 30 weeks, respectively. Angiography showed normal aqueous humor drainage (Group 1) beginning at the perilimbal trabecular plexus and continuing posteriorly to episcleral outflow vessels. Following implantation, drainage occurred preferentially and directly into the subconjunctival bleb. Conclusions: Gel stent implantation with MMC SR was most effective in achieving sustained, long-term IOP reduction in the rabbit model, compared with implantation with or without MMC solution. Bleb presence and the postimplantation aqueous angiography results indicated redirection of the AHO to the subconjunctival vasculature and presumed lymphatics, suggesting efficient glaucoma filtration to lower IOP in this model. This rabbit model and aqueous angiography may help refine understanding of the mechanism of action of minimally invasive glaucoma surgeries and ultimately translate to improved surgical devices and procedures for patients with glaucoma.

Exposure of Bladder Cancer Cells to Blue Light (λ = 453 nm) in the Presence of Riboflavin Synergistically Enhances the Cytotoxic Efficiency of Gemcitabine

Non-muscle invasive bladder cancer is a common tumour in men and women. In case of resistance to the standard therapeutic agents, gemcitabine can be used as off-label instillation therapy into the bladder. To reduce potential side effects, continuous efforts are made to optimise the therapeutic potential of drugs, thereby reducing the effective dose and consequently the pharmacological burden of the medication. We recently demonstrated that it is possible to significantly increase the therapeutic efficacy of mitomycin C against a bladder carcinoma cell line by exposure to non-toxic doses of blue light (453 nm). In the present study, we investigated whether the therapeutically supportive effect of blue light can be further enhanced by the additional use of the wavelength-specific photosensitiser riboflavin. We found that the gemcitabine-induced cytotoxicity of bladder cancer cell lines (BFTC-905, SW-1710, RT-112) was significantly enhanced by non-toxic doses of blue light in the presence of riboflavin. Enhanced cytotoxicity correlated with decreased levels of mitochondrial ATP synthesis and increased lipid peroxidation was most likely the result of increased oxidative stress. Due to these properties, blue light in combination with riboflavin could represent an effective therapy option with few side effects and increase the success of local treatment of bladder cancer, whereby the dose of the chemotherapeutic agent used and thus the chemical load could be significantly reduced with similar or improved therapeutic success.

Does Idiopathic Subglottic Stenosis Length and Location Change with Serial Endoscopic Interventions?

OBJECTIVES/HYPOTHESIS

The aim was to assess changes in physical parameters of subglottic stenosis (SGS) following serial endoscopic surgical intervention.

STUDY DESIGN

This was a retrospective chart review.

METHODS

A retrospective review of 52 idiopathic subglottic stenosis (iSGS) patients undergoing multiple endoscopic (excision/dilation) procedures between 2014 and 2022 was completed. Parameters including proximal stenosis distance from the vocal process and total stenosis length collected intraoperatively were compared over serial treatments. Differences between patient variables affecting distances from the vocal process and mean stenosis length were statistically analyzed utilizing nonparametric estimators including the Mann Whitney U, Fisher exact, and linear regression models.

RESULTS

For the cohort of iSGS patients (N = 52), the mean age was 55.1 (±15.1). The patients were predominantly female (96.2%) and Caucasian (84.6%). Patients underwent an average of 3.4 (±1.3) endoscopic procedures for long-term treatment of iSGS (range: 1 to 5 procedures). Patients undergoing a total of two (2) total procedures within the data collection window demonstrated a statistically significant decrease in mean stenosis length between the first and second procedures (p = 0.014). Changes in distance of the stenosis from the glottis was not found to be statistically significant (p = 0.833). There was a statistically significant decrease in mean length of stenosis from the 1st to the 2nd procedure by approximately 0.11 cm (p = 0.0003). No additional statistically significant differences in stenosis length or location were detected.

CONCLUSIONS

Serial endoscopic excision/dilation procedures (the mainstay of iSGS surgical management) do not appear to significantly lengthen intraluminal stenosis nor change the distance of the stenosis from the glottis.

LEVEL OF EVIDENCE

4 Laryngoscope, 134:1769-1772, 2024.

Cytogenetic findings in Polish patients with suspected Fanconi anemia

BACKGROUND

The high sensitivity of cells of Fanconi anemia (FA) patients to DNA cross-linking agents (clastogens), such as mitomycin C (MMC), was used as a screening tool in Polish children with clinical suspicion of FA.

OBJECTIVES

The aim of the study was to compare chromosome fragility between 3 groups, namely non-FA, possible mosaic FA and FA patients.

MATERIAL AND METHODS

The study included 100 children with hematological manifestations and/or congenital defects characteristic of FA, and 100 healthy controls. Blood samples obtained from participants were analyzed using an MMC-induced chromosomal breakage test.

RESULTS

Patients with clinical suspicion of FA were divided into 3 subgroups based on the MMC test results, namely FA, possible mosaic FA and non-FA. Thirteen out of 100 patients had a true FA cellular phenotype. The mean value of MMC-induced chromosome breaks/cell for FA patients was higher than for non-FA patients (6.67 ±3.92 compared to 0.23 ±0.18). In addition, the percentage of cells with spontaneous aberrations was more than 9 times higher in FA patients than in non-FA patients.

CONCLUSIONS

Our results confirmed that the MMC sensitivity test distinguishes between individuals affected by FA, those with possible somatic mosaicism, and patients with bone marrow failure for other reasons, who were classified as non-FA in the first diagnostic step. However, a definitive differential diagnosis requires follow-up mutation testing and chromosome breakage analysis of skin fibroblasts.

[New minimally invasive treatment options in benign and malignant otorhinolaryngological diseases using nanostructured drug delivery systems]

A fej-nyaki daganatok ma Magyarországon a 4. leggyakoribb daganatos betegségek. Az etiológiai faktorokat tekintve vezető tényező a dohányzás és az alkoholfogyasztás. Ezek hiányában a HPV-pozitivitás számít oki tényezőnek. Az eredményes kezelés egyénre szabottan ötvözi a sebészi, kemo-, sugár- és immunterápiát. Munkánkban a kemoterápiás szerek mellékhatásprofiljának szűkítését próbáltuk csökkenteni két ismert és széles körben használt kemoterapeutikumot, ciszplatint és mitomicin C-t tartalmazó, új nanotechnológiai gyógyszerbeviteli rendszer kialakításával. A poli(vinil-alkohol)-tartalmú szintetikus polimerből gyógyszerbeviteli rendszert alakítottunk ki, mely tartalmazza a ciszplatin vagy mitomicin C kemoterapeutikumot. A nanotechnológiai gyógyszerleadó rendszer a célterületre való bevitel után a hatóanyagot koncentrációfüggő mennyiségben, időkontrolláltan adja le a kívánt hatás eléréséhez. Vizsgált szintetikus polimerünk a mukoadhezív, biokompatibilis, biodegradábilis tulajdonságait kiaknázva a hatóanyag leadása után eliminálódik. Ez a korszerű nanotechnológiai gyógyszerbeviteli rendszer egy új lokális kemoterápia lehetőségét veti fel, mellyel nagy fokban csökkenthetjük a kemoterápiás szerek ismert, sok esetben a kemoterápiás kezelés felfüggesztését okozó, súlyos, életet veszélyeztető mellékhatásait. Orv Hetil. 2024; 165(10): 370–378.

Additive Manufacturing of Iron Carbide Incorporated Bioactive Glass Scaffolds for Bone Tissue Engineering and Drug Delivery Applications

In this study, we have synthesized a bioactive glass with composition 45SiO2-20Na2O-23CaO-6P2O5-2.5B2O3-1ZnO-2MgO-0.5CaF2 (wt %). Further, it has been incorporated with 0.4 wt % iron carbide nanoparticles to prepare magnetic bioactive glass (MBG) with good heat generation capability for potential applications in magnetic field-assisted hyperthermia. The MBG scaffolds have been fabricated using extrusion-based additive manufacturing by mixing MBG powder with 25% Pluronic F-127 solution as the binder. The saturation magnetization of iron carbide nanoparticles in the bioactive glass matrix has been found to be 80 emu/g. The morphological analysis (pore size distribution, porosity, open pore network modeling, tortuosity, and pore interconnectivity) was done using an in-house developed methodology that revealed the suitability of the scaffolds for bone tissue engineering. The compressive strength (14.3 ± 1.6 MPa) of the MBG scaffold was within the range of trabecular bone. The in vitro test using simulated body fluid (SBF) showed the formation of apatite indicating the bioactive nature of scaffolds. Further, the drug delivery behaviors of uncoated and polycaprolactone (PCL) coated MBG scaffolds have been evaluated by loading an anticancer drug (Mitomycin C) onto the scaffolds. While the uncoated scaffold demonstrated the drug's burst release for the initial 80 h, the PCL-coated scaffold showed the gradual release of the drug. These results demonstrate the potential of the proposed MBG for bone tissue engineering and drug delivery applications.

Combination intravesical chemotherapy for non-muscle invasive bladder cancer (NMIBC) as first-line or rescue therapy: where do we stand now?

INTRODUCTION

The combination of intravesical gemcitabine (Gem) with docetaxel (Doce) or with mitomycin C (MMC) has been used in the primary setting as an alternative to Bacillus Calmette-Guerin (BCG) to treat high-risk (HR) and intermediate-risk (IR) non-muscle invasive bladder cancer (NMIBC), as well in the rescue setting for patients in whom BCG has failed.

AREA COVERED

Efficacy and safety of Gem/Doce and Gem/MMC to treat NMIBC in BCG-naive and failure settings.

EXPERT OPINION

In the BCG-naive setting, Gem/Doce was the primary alternative combination therapy reported, with a weighted mean of 12- and 24-month recurrence-free survival (RFS) of 79% and 77% for HR disease and 84% and 76% for IR disease, respectively. In the HR BCG-failure setting, the weighted mean of 12- and 24-month RFS was 60% and 42% for Gem/Doce and 63% and 40% for Gem/MMC. While patients without BCG exposure and papillary disease only benefit the most from Gem/Doce, there is also reasonable efficacy in BCG refractory disease and CIS. Combination therapy is well tolerated, with grade III toxicity reported in less than 1% of patients. Unlike single-agent chemotherapy, intravesical Gem/Doce is considered effective and safe regardless of risk-stratification.

Seasonal trends in lysogeny in an Appalachian oak-hickory forest soil

Since 1989, investigations into viral ecology have revealed how bacteriophages can influence microbial dynamics within ecosystems at global scales. Most of the information we know about temperate phages, which can integrate themselves into the host genome and remain dormant via a process called lysogeny, has come from research in aquatic ecosystems. Soil environments remain under-studied, and more research is necessary to fully understand the range of impacts phage infections have on the soil bacteria they infect. The aims of this study were to compare the efficacy of different prophage-inducing agents and to elucidate potential temporal trends in lysogeny within a soil bacterial community. In addition to mitomycin C and acyl-homoserine lactones, our results indicated that halosulfuron methyl herbicides may also be potent inducing agents. In optimizing chemical induction assays, we determined that taking steps to reduce background virus particles and starve cells was critical in obtaining consistent results. A clear seasonal trend in inducible lysogeny was observed in an Appalachian oak-hickory forest soil. The average monthly air temperature was negatively correlated with inducible fraction and burst size, supporting the idea that lysogeny provides a mechanism for phage persistence when temperatures are low and host metabolism is slower. Furthermore, the inducible fraction was negatively correlated with both soil bacterial and soil viral abundance, supporting the idea that lysogeny provides a mechanism for temperate phage persistence when host density is lower. The present study is the first of its kind to reveal clear seasonal trends in inducible lysogeny in any soil.IMPORTANCELysogeny is a relationship in which certain viruses that infect bacteria (phages) may exist within their bacterial host cell as a segment of nucleic acid. In this state, the phage genome is protected from environmental damage and retains the potential to generate progeny particles in the future. It is thought that lysogeny provides a mechanism for long-term persistence for phages when host density is low or hosts are starved-two conditions likely to be found in soils. In the present study, we provide the first known evidence for a seasonal trend in lysogeny in a forest soil. Based on clear relationships observed between lysogeny, temperature, and soil microbial abundance, we find support for previous hypotheses regarding the factors governing lysogeny.

Critical Stenosis Because of Vocal Cord Synechiae in a Child

Stridor is a clinical sign of an underlying disease and a common reason for pediatric emergency department (PED) consultation. Patients presenting with stridor must be evaluated to determine the origin of this abnormality. We present the case of a 7-year-old female patient who presented to our Pediatric Emergency Department with a history of recurrent episodes of stridor with increasing frequency over the previous 4 years, for this reason she was previously admitted to the pediatric intensive care unit. Findings from the otorhinolaryngologic assessment with flexible fiber-optic endoscopy led to a diagnosis of congenital synechia of the vocal cords. The cervical CT scan evidenced critical stenosis of the airway. An initial cordectomy and placement of a silicone device for fixation were performed. Subsequently, the patient required 6 additional interventions for progressive dilation of the glottic space at the level of the vocal cords and injections of mitomycin C injections (an antineoplastic that inhibits collagen proliferation). This case highlights the importance of additional studies (especially examination of the upper airway) when atypical or recurrent findings are revealed by the clinical history, physical examination, or disease course in patients with croup to prioritize cases severe enough to require pediatric intensive care unit admission.

Intravesical mitomycin C efficacy in acidic and alkaline urinary pH: impact on recurrence-free survival rate after TURBT

Background

Urinary bladder tumor recurrence following transurethral resection of bladder tumor (TURBT) is a common issue. This study aims to determine how urine alkalinization affects bladder tumor recurrence after surgery.

Materials and methods

Sixty patients receiving mitomycin C (MMC) therapy after TURBT were divided into two groups based on mean pH values. Twenty-six patients were in group A, whose urine pH was below 5.5. However, there were 34 patients in group B, and their urine pH was higher than 5.5. Both groups of patients were given intravesical MMC once weekly for 6 weeks following TURBT. A cystoscopy was performed as a follow-up at 3, 6, and 12 months. Urine pH and the recurrence-free survival rate were compared using Kaplan-Meier survival analysis and the COX proportional hazard model.

Results

The mean time to tumor recurrence in group A (intravesical MMC in acidic urine) and group B (intravesical MMC in alkaline urine) was 12.48 versus 16.84 months, respectively. Alkaline urine pH was identified as an independent predictor of preventing the recurrence of superficial bladder tumors by univariate COX regression analysis. Age, sex, and mean tumor size did not affect the likelihood of tumor recurrence. However, smoking had an association with increased tumor recurrence.

Conclusion

Tumor recurrence post-TURBT is delayed in patients with alkaline urine pH. Smoking is an independent risk factor for bladder tumors.

Evaluation of the Effect of an Intraperitoneal Cytostatic-Loaded Supramolecular Hydrogel on Intestinal Anastomotic Healing in an Animal Model

The prognosis of colorectal cancer patients with peritoneal metastases is very poor. Intraperitoneal drug delivery systems, like supramolecular hydrogels, are being developed to improve local delivery and intraperitoneal residence time of a cytostatic such as mitomycin C (MMC). In this study, we evaluate the effect of intraperitoneal hydrogel administration on anastomotic healing. Forty-two healthy Wistar rats received a colonic end-to-end anastomosis, after which 6 animals received an intraperitoneal injection with saline, 18 with unloaded hydrogel and 18 with MMC-loaded hydrogel. After 7 days, animals were euthanized, and the anastomotic adhesion and leakage score were measured as primary outcome. Secondary outcomes were bursting pressure, histological anastomosis evaluation and body weight changes. Twenty-two rats completed the follow-up period (saline: n = 6, unloaded hydrogel: n = 10, MMC-loaded hydrogel: n = 6) and were included in the analysis. A trend towards significance was found for anastomotic leakage score between the rats receiving saline and unloaded hydrogel after multiple-comparison correction (p = 0.020, α = 0.0167). No significant differences were found for all other outcomes. The main reason for drop-out in this study was intestinal blood loss. Although the preliminary results suggest that MMC-loaded or unloaded hydrogel does not influence anastomotic healing, the intestinal blood loss observed in a considerable number of animals receiving unloaded and MMC-loaded hydrogel implies that the injection of the hydrogel under the studied conditions is not safe in the current rodent model and warrants further optimalisation of the hydrogel.

Intravesical Therapy for Upper Urinary Tract Urothelial Carcinoma: A Comprehensive Review

Upper tract urothelial carcinoma (UTUC) poses unique challenges in diagnosis and treatment. This comprehensive review focuses on prophylactic intravesical therapy for UTUC, summarizing key aspects of intravesical therapy in various clinical scenarios, including concurrent with or following radical nephroureterectomy, kidney-sparing surgery, ureteroscopy-guided biopsy. The incidence of intravesical recurrence in UTUC after surgical treatment is significant, necessitating effective preventive measures. Intravesical therapy plays a vital role in reducing the risk of bladder recurrence following UTUC surgery. Tailoring timing, drug selection, dosage, and frequency is vital in optimizing treatment outcomes and reducing intravesical recurrence risk in UTUC. This review provides a comprehensive summary of the history, clinical trials, guideline recommendations, and clinical applications of intravesical therapy for UTUC. It also discusses the future directions based on current clinical needs and ongoing trials. Future directions entail optimizing dosage, treatment duration, and drug selection, as well as exploring novel agents and combination therapies. Intravesical therapy holds tremendous potential in improving outcomes for UTUC patients and reducing the risk of bladder recurrence. Although advancements have been made in UTUC treatment research, further refinements are necessary to enhance efficacy and safety.

A Degradable Sustained-Release Drug Delivery System for Bleb-Forming Glaucoma Surgery

Fibrosis of the filtering bleb is one of the main causes of failure after bleb-forming glaucoma surgery. Intraoperative application of mitomycin C (MMC) is the current gold standard to reduce the fibrotic response. However, MMC is cytotoxic and one-time application is often insufficient. A sustained-release drug delivery system (DDS), loaded with MMC, may be less cytotoxic and equally or more effective. Two degradable (polycaprolactone (PCL) and polylactic-co-glycolic acid (PLGA)) MMC-loaded DDSs are developed. Release kinetics are first assessed in vitro followed by rabbit implants in conjunction with the PRESERFLO MicroShunt. As a control, the MicroShunt is implanted with adjunctive use of a MMC solution. Rabbits are euthanized at postoperative day (POD) 28 and 90. The PLGA and PCL DDSs release (on average) 99% and 75% of MMC, respectively. All groups show functioning blebs until POD 90. Rabbits implanted with a DDS show more inflammation with avascular thin-walled blebs when compared to the control. However, collagen is more loosely arranged. The PLGA DDS shows less inflammation, less foreign body response (FBR), and more complete degradation at POD 90 when compared to the PCL DDS. Further optimization with regard to dosage is required to reduce side effects to the conjunctiva.

Morphological features of regenerative processes after dacryocystorinostomy with the use of mitomycin C

PURPOSE

To study the morphological features of regenerative processes in dynamics after dacryocystorinostomy (DCR) with the use of Mitomycin C (MMC).

METHODS

The study includes 31 cases. All patients underwent endonasal endoscopic DCR. Group 1 included 16 cases who received MMC injections. Group 2 included 15 cases who were treated with MMC on collagen sponge into the area of formed anastomosis. Biopsies for histological examination were taken on the 2nd, 5th, 7th, 14th, 21st, 28th and 60th days after the surgery. The samples were subjected to histological examination.

RESULTS

Activated fibroblasts were detected in patients of group 2 on the 5th day after the surgery which became the main cellular elements by the 14th day, and incomplete fibroblast mitoses were observed in group 1 by the 14th day. On the 28th day after the surgery, the transformation of the extracellular matrix into loose connective tissue was determined in patients of group 2, while single cellular elements represented by fibroblasts were preserved in biopsies obtained from patients of group 1. By the 60th day after the surgery, the restoration of a full-fledged epithelial lining was observed in all specimens.

CONCLUSION

With the injection of MMC, inhibition of collagenogenesis by depression of extracellular collagen matrix formation, production of abortive mitoses in cells and inhibition of maturation and transformation of fibroblasts occur. The regeneration process takes place after MMC injection under a relative decrease in fibroblast impact.

Prognostic indicators for colorectal peritoneal metastases are different for patients with complete versus incomplete cytoreductive surgery

BACKGROUND

In the management of peritoneal metastases in patients with colorectal cancer, the completeness of cytoreduction has consistently been the most prominent prognostic indicator. Other clinical and histologic features have been described that may also have an impact on survival.

METHODS

The colorectal peritoneal metastases patients treated by cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy were divided into two groups. One group had complete CRS and the second group had an incomplete CRS. The prognostic variables in these two groups of patients were statistically analyzed for their impact on survival.

RESULTS

In the complete CRS group of 124 patients lymph node positivity, poorly differentiated histopathology, asymptomatic status following treatment with systemic chemotherapy, incomplete response to systemic chemotherapy, and moderate to high peritoneal cancer index showed a significantly reduced survival. All five of these prognostic variables ceased to show statistical significance in the group of 82 patients with incomplete cytoreduction.

CONCLUSION

The cause for significance of five prognostic indicators identified in patients with complete cytoreduction versus loss of significance of these indicators in patients with incomplete cytoreduction has not been determined. An absence of residual disease in complete CRS patients and a widely variable extent of residual disease in incomplete CRS patients may be important. Prognostic indicators in patients with colorectal peritoneal metastases find their greatest usefulness in patients who have had a complete cytoreduction.

Visual outcomes and recurrence rate of macular corneal dystrophy following phototherapeutic keratectomy in Saudi Arabia

PURPOSE

The purpose of the study was to evaluate the visual outcomes and recurrence rate of patients with macular corneal dystrophy (MCD) who have undergone phototherapeutic keratectomy (PTK).

METHODS

This retrospective, single-centered study enrolled patients from King Khaled Eye Specialist Hospital who had undergone PTK for MCD between 2000 and 2020. Pre-, intra-, and post-operative data were collected, and the primary outcome measures included uncorrected visual acuity, best-corrected visual acuity (BCVA), spherical equivalent, central keratometry, keratometric astigmatism, recurrence rate, and necessity of subsequent surgery.

RESULTS

This study evaluated 42 eyes of 29 patients. BCVA improved from 0.41 (±0.17) preoperatively to 0.30 (±0.16) postoperatively. Sixteen out of 42 eyes (38%) had the recurrence of macular dystrophy deposits within the stroma; the average time from PTK to recurrence was 37 months (range: 5.5-115.4 months). The overall success rate of PTK at 2 years was 44.8%. Eleven eyes (26%) required subsequent surgery following PTK at an average of 43 months postoperatively. Deeper ablation and longer application of mitomycin C (MMC) were both found to be statistically significant factors associated with visual improvement and lower recurrence rate following PTK.

CONCLUSION

PTK can be considered a treatment modality for younger patients to defer keratoplasty to a later stage. Deeper ablation is associated with improved postoperative visual acuity, and longer application of MMC is associated with lower recurrence rates of MCD.

Toxic anterior segment syndrome following trabeculectomy with mitomycin C

Objective

Toxic anterior segment (TASS) is a rare acute sterile anterior segment inflammation that typically develops within 12 to 24 hours after an anterior segment surgery. The purpose of this case report is to alert surgeons to the possibility of this complication following any anterior segment surgery, including trabeculectomy, and to highlight the possible etiologies and measures to prevent it.

Patient and method

A 58-year-old male glaucoma patient was initially managed medically for primary open angle glaucoma with antiglaucoma medications. There was rapidly progressive glaucomatous optic nerve damage in his left eye within the following year, despite the use of antiglaucoma medications, hence the need for trabeculectomy.

Result

The post-operative condition of the patient's eye was stormy with diffuse limbus-to-limbus corneal edema and profound Descemet's membrane folds, among other features of TASS, with associated deteriorating visual acuity.

Conclusion

Although there is no documented report of TASS following trabeculectomy with mitomycin C, surgeons should be alerted to this possibility. Preventive measures include extreme care to avoid errors while preparing and administering diluted solutions, especially medications that are administered into the intracameral space.

Effects of cyclophosphamide and mitomycin C on radiation-induced transcriptional biomarkers in human lymphoblastoid cells

PURPOSE

Ionizing radiation (IR)-induced transcriptional changes are considered a potential biodosimetry for dose evaluation and health risk monitoring of acute or chronic radiation exposure. It is crucial to understand the impact of confounding factors on the radiation-responsive gene expressions for accurate and reproducible dose assessment. This study aims to explore the potential influence of exposures to chemotherapeutic agents such as cyclophosphamide (CP) and mitomycin C (MMC) on IR-induced transcriptional biomarkers.

METHODS

The human B lymphoblastoid cells (AHH-1) were exposed to 0, 20, 50, 100, 200 and 500 μg/ml CP or 0, 0.025, 0.05, 0.1 and 1 μg/ml MMC, respectively. The appropriate concentrations of CP and MMC were added for 1 h before irradiation with 0, 2, 4 and 6 Gy of 60Co γ-rays at a dose rate of 1 Gy/min. Cell viability was evaluated by CCK-8 assay. The gene expression responses of 18 radiation-induced transcriptional biomarkers were examined at 24 h after exposures to CP and MMC, respectively. The expression levels of five crucial DNA interstrand crosslinks (ICLs) repair genes were also evaluated. The biodosimetry models were established based on the specific radiation-responsive gene combinations.

RESULTS

The baseline transcriptional levels of the 18 selected genes were slightly affected by CP treatment in the absence of IR, while the transcript responses to IR could be inhibited as the concentration of CP up to 50 μg/ml. MMC treatment up-regulated the background levels in most radiation-responsive gene expressions. Of 18 genes, only the relative mRNA expression levels of CDKN1A and BBC3 were repressed after treatment with IR and MMC in combination. The relative mRNA level of RAD51 was significantly up-regulated after exposure to CP, while the expression of FANCD2, RAD51 and BLM showed an overall increase in response to MMC treatment. After irradiation, the relative mRNA expression levels of FANCD2, BRCA2 and RAD51 exhibited dose-dependent increases in IR alone and MMC treatment groups. In addition, the biodosimetry models were established using 2-4 radiation-responsive genes based on different radiation exposure scenarios.

CONCLUSION

Our findings suggested that IR-induced gene expression changes were slightly affected after exposure to a relatively low concentration of CP and MMC. Gene expression combinations might improve the broad applicability of transcriptional biodosimetry across diverse radiation exposures.

Posterior scleral application of a mitomycin C-soaked sponge during trabeculectomy

AIM

To evaluate the safety and efficacy of posterior scleral application (a modified technique) of an antimetabolite mitomycin C-soaked sponge in trabeculectomy for patients with glaucoma.

METHODS

This retrospective study included 101 patients (115 eyes) with glaucoma (aged 12-83y) who underwent trabeculectomy using a modified mitomycin C-soaked sponge placement method. A piece of 3.5×10 mm2 sponge was placed vertically and posteriorly with the long side perpendicular to the limbus. The mitomycin C concentration and exposure time were 0.2-0.5 mg/mL and 1-5min, respectively. Intraocular pressure, best-corrected visual acuity, and hypotensive medications were recorded at baseline and at the final visit. Complications, interventions required, and bleb morphology were recorded postoperatively. The primary outcome was trabeculectomy safety, including complications and bleb morphology; the secondary outcome was the trabeculectomy success rate.

RESULTS

At the final follow-up [median 28mo, range 7-67mo and interquartile range (IQR) 13mo], the qualified (cumulative) success rate was 93.0% and the complete success rate was 60.0%. No bleb-related complications were observed. The mean height, extent, and vascularity grades were 0.6±0.9, 1.1±0.4, and 2.4±0.9, respectively. All Seidel tests were negative. The mean posteriority grade was 0.8±0.4.

CONCLUSION

Trabeculectomy with the long side of a mitomycin C-soaked sponge placed perpendicular to the corneal limbus is safe and effective.

Codelivery of TRAIL and Mitomycin C via Liposomes Shows Improved Antitumor Effect on TRAIL-Resistant Tumors

Although tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) constitutes a promising antitumor drug, tumor resistance to TRAIL has become a major obstacle in its clinical application. Mitomycin C (MMC) is an effective TRAIL-resistant tumor sensitizer, which indicates a potential utility of combination therapy. However, the efficacy of this combination therapy is limited owing to its short half-life and the cumulative toxicity of MMC. To address these issues, we successfully developed a multifunctional liposome (MTLPs) with human TRAIL protein on the surface and MMC encapsulated in the internal aqueous phase to codeliver TRAIL and MMC. MTLPs are uniform spherical particles that exhibit efficient cellular uptake by HT-29 TRAIL-resistant tumor cells, thereby inducing a stronger killing effect compared with control groups. In vivo assays revealed that MTLPs efficiently accumulated in tumors and safely achieved 97.8% tumor suppression via the synergistic effect of TRAIL and MMC in an HT-29 tumor xenograft model while ensuring biosafety. These results suggest that the liposomal codelivery of TRAIL and MMC provides a novel approach to overcome TRAIL-resistant tumors.

One-Year Outcomes of PreserfloTM MicroShunt Implantation versus Trabeculectomy for Pseudoexfoliation Glaucoma

This retrospective, single-center study evaluates the safety and efficacy of Preserflo^TM MicroShunt (MicroShunt) implantations compared to trabeculectomies (TETs) in patients diagnosed with pseudoexfoliation glaucoma (PEXG). A total of 31 eyes from 28 patients received a MicroShunt implantation, and 29 eyes from 26 patients received a TET. Surgical success was defined as an intraocular pressure (IOP) between 5 mmHg and 17 mmHg at the end of the follow-up period, no need for surgical revisions or secondary glaucoma surgery, and no loss of light perception. In the MicroShunt group, the mean IOP dropped from 20.8 ± 5.9 mmHg at baseline to 12.4 ± 2.8 mmHg (p < 0.0001) after one year. In the TET group, the mean IOP dropped from 22.3 ± 6.5 mmHg to 11.1 ± 3.7 mmHg (p < 0.0001) after 12 months. In both of the groups, the mean number of medications was reduced significantly (MicroShunt from 2.7 ± 1.2 to 0.2 ± 0.7; p < 0.0001 vs. TET from 2.9 ± 1.2 to 0.3 ± 0.9; p < 0.0001). Considering the success rates, 83.9% of the MicroShunt eyes achieved complete success, and 90.3% qualified for success at the end of the follow-up period. In the TET group, the rates were 82.8% and 93.1%, respectively. The postoperative complications were comparable between both groups. In conclusion, the MicroShunt implantation demonstrated non-inferiority regarding its efficacy and safety profile compared to TET in PEXG at a follow-up of one year.

Phytochemical Analysis and Genotoxicological Evaluation of Prickly Pear Peel Extracts

This study investigated the beneficial properties of prickly pear peel (PPP) extracts from Opuntia ficus-indica (L.) Mill. Extracts were obtained via the Soxhlet extraction method using methanol (P1), ethanol (P2) and ethanol-water (P3) as extraction solvents. Their total phenolic and flavonoid content (TPC and TFC, respectively) and their antioxidant activity (AA) were determined. The PPP extracts were characterized in detail using mass spectrometry techniques. Their cyto-genotoxic effect and antigenotoxic potential against mitomycin C were evaluated via the cytokinesis block micronucleus (CBMN) assay on human lymphocytes. Enhanced TPC, TFC and AA values were recorded for all the extracts. Moreover, P1 and P2 were cytotoxic only at the highest concentrations, whereas P3 was found to be cytotoxic in all cases. No significant micronucleus induction was observed in the tested extracts. The PPP extracts contain bioactive compounds such as flavonoids, carboxylic acids, alkaloids, fatty acids and minerals (mainly K, Si, Mg, Ca, P and Zn). The results showed that all three extracts exerted high antigenotoxic activity. Our findings confirm the beneficial and genoprotective properties of PPP extracts and further studies on the bioactive compounds of Opuntia ficus-indica (L.) Mill. are recommended, as it constitutes a promising plant in pharmaceutical applications.

Role of Extracellular DNA in Bacterial Response to SOS-Inducing Drugs

The SOS response is a conserved stress response pathway that is triggered by DNA damage in the bacterial cell. Activation of this pathway can, in turn, cause the rapid appearance of new mutations, sometimes called hypermutation. We compared the ability of various SOS-inducing drugs to trigger the expression of RecA, cause hypermutation, and produce elongation of bacteria. During this study, we discovered that these SOS phenotypes were accompanied by the release of large amounts of DNA into the extracellular medium. The release of DNA was accompanied by a form of bacterial aggregation in which the bacteria became tightly enmeshed in DNA. We hypothesize that DNA release triggered by SOS-inducing drugs could promote the horizontal transfer of antibiotic resistance genes by transformation or by conjugation.

Thiolated Mesoporous Silica Nanoparticles as an Immunoadjuvant to Enhance Efficacy of Intravesical Chemotherapy for Bladder Cancer

The characteristics of global prevalence and high recurrence of bladder cancer has led numerous efforts to develop new treatments. The spontaneous voiding and degradation of the chemodrug hamper the efficacy and effectiveness of intravesical chemotherapy following tumor resection. Herein, the externally thiolated hollow mesoporous silica nanoparticles (MSN-SH(E)) is fabricated to serve as a platform for improved bladder intravesical therapy. Enhanced mucoadhesive effect of the thiolated nanovector is confirmed with porcine bladder. The permeation-enhancing effect is also verified, and a fragmented distribution pattern of a tight junction protein, claudin-4, indicates the opening of tight junction. Moreover, MSN-SH(E)-associated reprogramming of M2 macrophages to M1-like phenotype is observed in vitro. The antitumor activity of the mitomycin C (MMC)-loaded nanovector (MMC@MSN-SH(E)) is more effective than that of MMC alone in both in vitro and in vivo. In addition, IHC staining is used to analyze IFN-γ, TGF-β1, and TNF-α. These observations substantiated the significance of MMC@MSN-SH(E) in promoting anticancer activity, holding the great potential for being used in intravesical therapy for non-muscle invasive bladder cancer (NMIBC) due to its mucoadhesivity, enhanced permeation, immunomodulation, and prolonged and very efficient drug exposure.

The Controlled Release and Prevention of Abdominal Adhesion of Tannic Acid and Mitomycin C-Loaded Thermosensitive Gel

Postoperative abdominal adhesion is one of the most common complications after abdominal surgery. A single drug or physical barrier treatment does not achieve the ideal anti-adhesion effect. We developed a thermosensitive hydrogel (PPH hydrogel) consisting of poloxamer 407 (P407), poloxamer (P188), and hydroxypropyl methylcellulose (HPMC) co-blended. An injectable thermosensitive TA/MMC-PPH hydrogel was obtained by loading tannic acid (TA) with an anti-inflammatory effect and mitomycin C (MMC), which inhibits fibroblast migration or proliferation. The optimal prescriptions of PPH hydrogels with a suitable gelling time (63 s) at 37 °C was 20% (w/v) P407, 18% (w/v) P188, and 0.5% (w/v) HPMC. The scanning electron microscopy (SEM) revealed that the PPH hydrogel had a three-dimensional mesh structure, which was favorable for drug encapsulation. The PPH hydrogel had a suitable gelation temperature of 33 °C, a high gel strength, and complicated viscosity at 37 °C, according to the rheological analysis. In vitro release studies have shown that the PPH hydrogel could delay the release of TA and MMC and conform to the first-order release rate. Anti-adhesion tests performed on rats in vivo revealed that TA/MMC-PPH hydrogel significantly reduced the risk of postoperative adhesion. In conclusion, the TA/MMC-PPH hydrogel prepared in this study showed an excellent performance in both controlled drug release and anti-adhesive effects. It can be used as a protocol to prevent or reduce postoperative abdominal adhesion.

Streptococcus pyogenes Φ1207.3 Is a Temperate Bacteriophage Carrying the Macrolide Resistance Gene Pair mef(A)-msr(D) and Capable of Lysogenizing Different Streptococci

Streptococcus pyogenes prophage Φ1207.3 (formerly Tn1207.3) carries the mef(A)-msr(D) resistance genes, responsible for type M macrolide resistance. To investigate if Φ1207.3 is a functional bacteriophage, we transferred the element from the original S. pyogenes host in a prophage-free and competence-deficient S. pneumoniae strain. Pneumococcal cultures of the Φ1207.3-carrying lysogen were treated with mitomycin C to assess if Φ1207.3 enters the lytic cycle. Mitomycin C induced a limited phage burst and a growth impairment, resulting in early entrance into the stationary phase. To determine if Φ1207.3 is able to produce mature phage particles, we prepared concentrated supernatants recovered from a mitomycin C-induced pneumococcal culture by sequential centrifugation and ultracentrifugation steps. Negative-staining transmission electron microscopy (TEM) of supernatants revealed the presence of phage particles with an icosahedral, electron-dense capsid and a long, noncontractile tail, typical of a siphovirus. Quantification of Φ1207.3 was performed by quantitative PCR (qPCR) and semiquantitatively by TEM. PCR quantified 3.34 × 104 and 6.06 × 104 excised forms of phage genome per milliliter of supernatant obtained from the untreated and mitomycin C-treated cultures, respectively. By TEM, we estimated 3.02 × 103 and 7.68 × 103 phage particles per milliliter of supernatant. The phage preparations of Φ1207.3 infected and lysogenized pneumococcal recipient strains at a frequency of 7.5 × 10-6 lysogens/recipient but did not show sufficient lytic activity to form plaques. Phage lysogenization efficiently occurred after 30 min of contact of the phages with the recipient cells and required a minimum of 103 phage particles. IMPORTANCE Bacteriophages play an important role in bacterial physiology and genome evolution. The widespread use of genome sequencing revealed that bacterial genomes can contain several different integrated temperate bacteriophages, which can constitute up to 20% of the genome. Most of these bacteriophages are only predicted in silico and are never shown to be functional. In fact, it is often difficult to induce the lytic cycle of temperate bacteriophages. In this work, we show that Φ1207.3, a peculiar bacteriophage originally from Streptococcus pyogenes, which can lysogenize different streptococci and carries the macrolide resistance mef(A)-msr(D) gene pair, is capable of producing mature virions, but only at a low level, while not being able to produce plaques. This temperate phage is probably a partially functional phage, which seems to have lost lytic characteristics to specialize in lysogenization. While we are not used to conceiving phages separately from lysis, this behavior could actually be more frequent than expected.

Total abdominal colectomy to facilitate complete cytoreduction in 56 patients with mucinous appendiceal neoplasms with peritoneal metastases

BACKGROUND

Cytoreductive surgery (CRS) and perioperative intraperitoneal chemotherapy are currently the standard of care for management of appendiceal mucinous neoplasms with peritoneal metastases. The goal of the CRS is complete removal of all visible disease through the use of peritonectomy procedures and visceral resections. One of the major resections that may be required is total abdominal colectomy (TAC).

METHODS

From a database and secured files of patients having a complete CRS, all patients who had TAC were identified. The clinical and histologic variables associated with these patients were identified and assessed for their impact on overall survival.

RESULTS

The 450 complete CRS with low-grade appendiceal mucinous neoplasms had 26 TAC (5.8%) with a 16.0-year median survival. The mucinous adenocarcinoma (MACA)-Intermediate (MACA-Int) group consisted of 37 patients with 8 patients (21.6%) having TAC that resulted in a median survival of 11.5 years. The 159 complete CRS with MACA had 22 TAC (13.8%) with a median survival of 7.5 years. There was a single mortality with a class 4 adverse event in 5 patients (10.7%). With a class 4 adverse event, survival decreased significantly (p = 0.0006, hazard ratio: 6.2).

CONCLUSION

Complete CRS required TAC in 56 of 646 patients (8.7%) with appendiceal mucinous neoplasms. With TAC, median survival was 12.0 years. A class 4 adverse event markedly reduced survival.

Outcomes of bleb needling in primary glaucoma: A prospective interventional study in a South Indian population

Purpose

This study was conducted to assess the outcomes of bleb needling for the treatment of failure of filtration surgeries in primary glaucoma with a follow-up of six months.

Methods

This prospective interventional study included patients with primary glaucoma who underwent trabeculectomy or combined glaucoma and cataract surgery with failed or failing bleb after six weeks of surgery and less than two years. A comprehensive examination including best-corrected visual acuity (BCVA), intraocular pressure (IOP) measurement, gonioscopy, slit-lamp examination, and bleb morphology grading was done. Selected patients underwent a subconjunctival bleb needling with mitomycin C (MMC) (dose 0.2 mg/ml). Postoperatively, patients were followed up on the first, third, and sixth months and were assessed with respect to IOP, need for antiglaucoma medication (AGM), and complications.

Results

Sixty eyes of 59 patients were included. Preoperatively, 33.3% of patients were on one AGM, whereas postoperatively at the third month 51.7% and at the sixth month 50% of patients were on no AGM. There was a statistically significant decrease in IOP (P < 0.001) from preoperative (mean: 23.8 ± 7.86 mmHg) to postoperative first month (mean: 19.8 ± 9.08 mmHg), third month (mean: 17.4 ± 5.4 mmHg) and sixth month (mean 16.6 ± 4.39). According to the defined criteria in the current study, we achieved 22 (37.9%) successes, 31 qualified successes (53.4%), and 5 (8.6%) failures. Univariate regression analysis showed a higher failure rate among younger age groups. Gender, laterality, and intraoperative complications were not significant statistically.

Conclusion

Bleb needling is a safe and effective procedure for the treatment of failed filtration surgeries.

Comparative evaluation of outcomes of novel approach of subconjunctival Mitomycin C (MMC) injection at the end of trabeculectomy versus intraTenon injection of MMC prior to the initial conjunctival incision - A pilot study

Purpose

To describe a novel approach of subconjunctival injection of mitomycin C (MMC) at the end of trabeculectomy and compare it with intraTenon MMC injection.

Methods

This pilot study included 40 eyes of 40 patients with uncontrolled primary and secondary glaucoma. Patients below18 years and failed trabeculectomy were excluded. Patients were randomly allocated into groups A and B (20 patients each). Group A patients received subconjunctival MMC injection in the superonasal quadrant at the end of standard trabeculectomy. Group B received an intraTenon MMC injection before the initial conjunctival incision. Outcome measures included intra-ocular pressure (IOP) reduction, bleb morphology, and complication rates. The complete success was defined as an IOP of ≤21 mmHg without antiglaucoma drugs.

Results

The mean preoperative IOP of 46.00 ± 11.2 mmHg in group A and 43.05 ± 10.3 mmHg in group B reduced to 12.00 ± 2.41 mmHg (P ≤ 0.001) in group A and 13.65 ± 2.76 mmHg in group B (P ≤ 0.001) at last follow-up. Complete success was 95% and 75% in groups A and B, respectively, 19 months after surgery. Avascular microcystic blebs (70% of group A and 45% of group B) were more common than avascular white blebs (15% in group A and 35% in group B). No intraoperative complications were seen. Postoperative wound leak, hypotony, choroidal detachment, or endophthalmitis were not encountered in any group.

Conclusion

A novel approach of subconjunctival MMC application during trabeculectomy is reported. Both approaches appear to be highly effective in reducing IOP in primary and secondary glaucoma with similar safety profiles and bleb morphology. Subconjunctival MMC yielded a greater success rate (95%) compared to the intraTenon MMC group (75%).

Novel NRF2-activated cancer treatments utilizing synthetic lethality

The KEAP1-NRF2 pathway regulates the main inducible cellular response to oxidative and electrophilic stresses. Activating mutations in the KEAP1-NRF2 pathway occur commonly in human cancer, where they contribute to the formation of aggressive tumours that are associated with a poor prognosis for patients. An important clinical feature of these tumours is their defiance to all current anti-cancer treatment regimens, highlighting the need for the development of new therapeutic strategies to target NRF2-activated cancers. In this review, we discuss the mechanisms through which acquired NRF2 hyperactivation can result in resistance of tumours to immune checkpoint inhibitor therapies in addition to classical chemotherapeutics, and propose with examples that using a synthetic lethal strategy mediated by NRF2-target gene-dependent bioactivation of prodrugs represents a promising strategy to specifically enhance toxicity to heretofore untreatable NRF2-hyperactivated human tumours.

Short-term surgical outcomes of twin-site combined phaco-emulsification and mitomycin-C augmented trabeculectomy in pseudo-exfoliation glaucoma versus primary open-angle glaucoma

Purpose

To compare the short-term outcomes of combined phaco-emulsification with posterior chamber intra-ocular lens and mitomycin augmented trabeculectomy in patients with pseudo-exfoliation glaucoma (PXFG) versus primary open-angle glaucoma (POAG).

Methods

A total of 144 eyes of 144 patients were enrolled in this prospective interventional comparative study, 72 each of which had PXFG and POAG, respectively. All patients underwent twin-site combined phaco-trabeculectomy at a tertiary eye center in India between December 2017 and December 2018 and were followed up for a period of 12 months. The main outcome measures were intra-ocular pressure (IOP), best corrected visual acuity (BCVA), total surgical time, rate of intra-operative and post-operative complications, and the number of ocular hypotensive medications needed. Success rates were determined via Kaplan-Meier survival analysis.

Results

The mean age was 63.9 ± 7.9 years in the POAG group and 66.4 ± 6.8 years in the PXFG group (P - 0.04). The baseline BCVA, IOP, and cup-disc ratio were comparable between two groups. Intra-operative complications and post-operative outcomes were comparable between the two groups. There was a significant drop in anti-glaucoma medications in both groups. Six patients, three (4.2%) in each group, were lost to follow-up after 6 months. Three patients (4.2%) in PXFG needed additional glaucoma intervention for controlling IOP, one patient needed a non-valved glaucoma drainage device, and two patients required diode cyclo-photocoagulation within the follow-up period.

Conclusion

Patients with PXFG had a longer surgical time than POAG. Similar success and complication rates were observed following combined twin-site phaco-trabeculectomy in both POAG and PXFG at 1 year. Combined glaucoma surgery resulted in good IOP control, improvement in BCVA, and lower requirement of ocular hypotensives in both the groups.

Effect of Prophylactic Mitomycin C on Corneal Endothelium Following Transepithelial Photorefractive Keratectomy in Myopic Patients

Purpose

This study investigated the effect of prophylactic mitomycin C (MMC) on corneal endothelium to inhibit corneal haze formation post transepithelial photorefractive keratectomy (T-PRK).

Methods

A total of 120 eyes of 60 patients with low, moderate, and high myopia were subjected to T-PRK with intraoperative application of MMC (0.02%) for 30-50s. Patients' files were categorized into three groups according to ablation depths (if ≥100 µm) during T-PRK as follows: (1) Group A - low myopia without MMC, (2) Group B - low myopia with MMC, and (3) Group C - moderate/high myopia with MMC. Preoperative/surgical parameters and refractive outcomes were documented. Cell density (CD), number of cells (NUM), coefficient of variation, central corneal thickness (CCT), hexagonality (HEX/6A), average cell area (AVG), and its standard deviation (SD) were evaluated using specular microscopy preoperatively and postoperatively.

Results

Overall, 119 out of 120 eyes showed significant prevention of corneal haze. Groups A and C showed no significant changes in endothelial CD and NUM. Group B showed a non-significant reduction in CD. However, all three groups showed significant variations in HEX/6A, CCT, AVG, and SD.

Conclusion

The MMC application did not significantly affect corneal endothelial density or number and can be used safely and effectively to prevent corneal haze following T-PRK in myopia.

RecA and RecB: probing complexes of DNA repair proteins with mitomycin C in live Escherichia coli with single-molecule sensitivity

The RecA protein and RecBCD complex are key bacterial components for the maintenance and repair of DNA. RecBCD is a helicase-nuclease that uses homologous recombination to resolve double-stranded DNA breaks. It also facilitates coating of single-stranded DNA with RecA to form RecA filaments, a vital step in the double-stranded break DNA repair pathway. However, questions remain about the mechanistic roles of RecA and RecBCD in live cells. Here, we use millisecond super-resolved fluorescence microscopy to pinpoint the spatial localization of fluorescent reporters of RecA or RecB at physiological levels of expression in individual live Escherichia coli cells. By introducing the DNA cross-linker mitomycin C, we induce DNA damage and quantify the resulting steady state changes in stoichiometry, cellular protein copy number and molecular mobilities of RecA and RecB. We find that both proteins accumulate in molecular hotspots to effect repair, resulting in RecA stoichiometries equivalent to several hundred molecules that assemble largely in dimeric subunits before DNA damage, but form periodic subunits of approximately 3-4 molecules within mature filaments of several thousand molecules. Unexpectedly, we find that the physiologically predominant forms of RecB are not only rapidly diffusing monomers, but slowly diffusing dimers.

Anterior Segment-Optical Coherence Tomography Bleb Morphology Comparison in Minimally Invasive Glaucoma Surgery: XEN Gel Stent vs. PreserFlo MicroShunt

Background: The purpose of this study is to compare the morphology of six-month follow-up blebs created by a subconjunctival glaucoma surgical device (XEN45) to those created by a PreserFlo MicroShunt with a sub-Tenon insertion, utilizing AS-OCT. Methods: A retrospective study of 29 eyes who underwent XEN45 implantation and 29 eyes who underwent PreserFlo MicroShunt implantation. The patients were analyzed at 24 h, 1 week, 1 month, 3 months and 6 months. At each visit, the maturation and morphological alterations of the blebs were observed, as well as connections with the IOP. Results: In both groups, IOP showed significant reduction at all follow ups (p < 0.0001). In XEN group, the most common bleb morphology in the immediate postoperative was the subconjuntival separation type (42%) followed by the uniform type (34%), with a trend inversion at 6 month follow up (51% of uniform type). On the contrary, the most common morphology after PreserFlo was the multiple internal layer (55%), which showed a tendency to reduce over time and was substituted by the microcystic multiform, whose percentage increased over time (17% at day 1 vs. 44% at month 6). Uniform appearance was associated by the posterior episcleral fluid (PEF) lake presence. Both horizontal and vertical diameters significantly increased over time. Conclusion: XEN and PreserFlo implantation resulted in the production of diffuse blebs with different characteristics, which may influence IOP lowering capacity and bleb revisions necessity over time.

[Transcription of DNA-Methyltransferases in Endothelial Cells Exposed to Mitomycin C]

DNA-methyltransferases catalyze DNA methylation in the CpG sites, which play an important role in the maintenance of genome stability. The association between DNA methylation and genotoxic stress resulting in the action of various clastogens has been shown. Genotoxic stress is one of the triggers of endothelial dysfunction. In this study, the transcription of DNMT1, DNMT3A and DNMT3B genes in coronary (HCAEC) and internal thoracic (HITAEC) artery endothelial cells exposed to alkylating mutagen mitomycin C was studied using quantitative polymerase chain reaction. In HCAEC exposed to mitomycin C, DNMT1 transcription is 1.7-fold higher compared to the unexposed control. After elimination of the mutagen from the cultures followed by 24-hours of cultivation, a 2-fold increase of transcription of DNMT3B in HCAEC exposed to mitomycin C compared to the control was observed. At the same time, no changes in transcription of the studied DNA-methyltransferases were found in HITAEC exposed to the mutagen. Thus, increased transcription of DNA-methyltransferase may be a possible molecular mechanism underlying endothelial dysfunction in response to mutagenic load in an in vitro experiment.

BRCA2 C-Terminal RAD51-Binding Domain Confers Resistance to DNA-Damaging Agents

Breast cancer type 2 susceptibility (BRCA2) protein is crucial for initiating DNA damage repair after chemotherapy with DNA interstrand crosslinking agents or X-ray irradiation, which induces DNA double-strand breaks. BRCA2 contains a C-terminal RAD51-binding domain (CTRBD) that interacts with RAD51 oligomer-containing nucleofilaments. In this study, we investigated CTRBD expression in cells exposed to X-ray irradiation and mitomycin C treatment. Surprisingly, BRCA2 CTRBD expression in HeLa cells increased their resistance to X-ray irradiation and mitomycin C. Under endogenous BRCA2 depletion using shRNA, the sensitivities of the BRCA2-depleted cells with and without the CTRBD did not significantly differ. Thus, the resistance to X-ray irradiation conferred by an exogenous CTRBD required endogenous BRCA2 expression. BRCA2 CTRBD-expressing cells demonstrated effective RAD51 foci formation and increased homologous recombination efficiency, but not nonhomologous end-joining efficiency. To the best of our knowledge, our study is the first to report the ability of the BRCA2 functional domain to confer resistance to X-ray irradiation and mitomycin C treatment by increased homologous recombination efficiency. Thus, this peptide may be useful for protecting cells against X-ray irradiation or chemotherapeutic agents.

Anterior-segment optical coherence tomography of filtering blebs in the early postoperative period of ab externo SIBS microshunt implantation with mitomycin C: Morphological analysis and correlation with intraocular pressure reduction

PURPOSE

To analyse the morphological evolution of filtering blebs with anterior-segment OCT (AS-OCT) and its correlation with intraocular pressure after ab externo SIBS microshunt implantation with mitomycin C (MMC) during a 3-month follow-up period.

METHODS

Twenty-eight filtering blebs of 28 patients with open-angle glaucoma were measured horizontally and vertically in the sub-Tenon space with AS-OCT after ab externo SIBS microshunt implantation with MMC. The intraocular pressure (IOP) was monitored simultaneously at each visit. Maturation of and morphological changes in the blebs and correlations with the IOP were recorded.

RESULTS

The average median preoperative IOP of 20.7 (range, 12-30) mmHg decreased to 8.5 (range, 4-17), 8.9 (range, 5-17), 10.4 (range, 8-16) and 10.9 (range, 9-15) mmHg at 24 hr, 1 week, 1 month and 3 months, respectively (p < 0.001). A multiform morphology on AS-OCT prevailed at all time points, with a 3.5% rate of a uniform bleb morphology at the first week. The horizontal and vertical diameters of the blebs increased from baseline to the third month. The horizontal expansion (406 ± 127 μm on day 7, p = 0.04, 712 ± 211 μm on day 30, p = 0.02 and 952 ± 218 μm on day 90, p < 0.001) was greater than the vertical expansion (16 ± 18 μm, p = 0.3 on day 1, 63 ± 27 μm, p = 0.02 on day 30 and 137 ± 34 μm, p < 0.001 on day 90) without correlation with the IOP (r = -0.3, p = 0.2).

CONCLUSION

Anterior-segment OCT (AS-OCT) of the filtering blebs formed after ab externo SIBS microshunt implantation showed progressive horizontal and vertical expansion of the blebs in the sub-Tenon space, with a significant peak at the first month not significantly correlated with the decrease in the IOP.

Revised prognostic indicators for treatment of lymph node positive colorectal peritoneal metastases

BACKGROUND

Peritoneal metastases from colon and rectal cancer presents a new target for a regional approach to treatment. Proper patient selection requires an understanding of the natural history of the disease progression.

METHODS

Data from colorectal cancer patients treated for peritoneal metastases by cytoreductive surgery (CRS) plus hyperthermic intraperitoneal chemotherapy and early postoperative intraperitoneal chemotherapy and the records from the primary colon or rectal cancer surgery were analyzed to assess their impact on survival. Data regarding the anatomic sites of colorectal peritoneal metastases was gathered at the time of a complete CRS.

RESULTS

A cohort of 73 patients with peritoneal metastases and lymph node metastases but no liver metastases provided the information. All patients had a complete cytoreduction. Left-sided primary cancer and a complete or near complete response to neoadjuvant chemotherapy (NAC) indicated improved survival. Tumor progression within the abdominal incision, carcinoembryonic antigen (CEA) >10, peritoneal cancer index >9 and peritoneal metastases present in the abdominopelvic regions 6 and 11 carried an especially guarded prognosis.

CONCLUSIONS

Reduced survival occurred with a right-sided or rectal primary cancer, a CEA >10, tumor cell entrapment, and involvement of abdominopelvic regions 6 and 11. Effective NAC showed a favorable outcome.

Combined photorefractive keratectomy and corneal collagen cross-linking for treatment of keratoconus: a 2-year follow-up study

Background:

Corneal collagen cross-linking (CXL) is considered an effective procedure for slowing down or eliminating the progression of keratoconus. New techniques, in combination with CXL, have been proposed to stop the evolution of keratoconus and improve the visual function.

Objective:

To evaluate the effectiveness of combined photorefractive keratectomy (PRK) with mitomycin-C (MMC) application and CXL in the management of grade 1–2 keratoconus over a 2-year follow-up.

Methods:

Fifteen eyes underwent topography-guided PRK with 0.02% MMC application immediately followed by standard CXL.

Results:

Best corrected visual acuity improved from 0.15 ± 0.11 logMAR to 0.08 ± 0.09 logMAR at 24 months (p < 0.0001) in treated eyes. Mean steepest meridian keratometry reduced from 48.79 ± 3.22 D at baseline to 46.16 ± 3.11 D at 24 months (p < 0.0001). Mean flattest meridian keratometry reduced from 45.18 ± 2.17 D preoperatively to 44.35 ± 2.19 D at 24 months (p < 0.0001).

Conclusion:

Simultaneous topography-guided PRK with MMC 0.02% application and standard CXL is a safe, promising and effective procedure in the treatment of mild and moderate keratoconus.

[Pharmacological modulation of wound healing in glaucoma surgery]

Despite the well-known effectiveness of pharmacological glaucoma therapy, surgical approach remains one of the main treatment options for some forms and stages of the disease. The long-term success of glaucoma surgery depends on the intensity of local wound healing processes at the surgical site. The most common way to influence healing processes in surgical treatment of glaucoma is the use of antimetabolites. However, given the high risk of serious complications associated with their use, the search for new drugs devoid of these disadvantages continues. The aim of this review is to describe the efficacy and safety of both currently used and upcoming pharmacological ways to influence the wound healing process after glaucoma surgery in order to improve the stability of hypotensive effect.

Long Term Outcomes of Surgical Excision of Giant Papillae with Mitomycin C and Amniotic Membrane Transplantation in the Treatment of Refractory Palpebral Vernal Keratoconjunctivitis

Background and Objectives: To report the long-term outcomes of patients with refractory Vernal Keratoconjunctivitis (VKC) who underwent surgical excision of giant papillae (GP) with mitomycin C (MMC) 0.02% and amniotic membrane transplantation (AMT). Materials and Methods: This is a retrospective interventional single-center case series including five eyes of four patients who had refractory, symptomatic VKC with GP, along with corneal shield ulcers and/or punctate epithelial erosions. They underwent surgical excision of GP with MMC 0.02% alone (1 eye) or with MMC 0.02% and AMT (4 eyes). Their long-term visual and surgical outcomes were studied. Results: All subjects were male with bilateral involvement and mean age of presentation 9.8 years. The surgery was uneventful in all cases. Amongst the four eyes which underwent MMC with AMT, only one eye demonstrated papillary regrowth requiring repeat surgery. Postoperative follow-up ranged from 59 to 77 months (median 66 months). Four patients had the best corrected visual acuity (BCVA) >/= 6/9.5. One patient had BCVA 6/15 at the final follow-up due to the presence of anterior corneal stromal scar and poor ocular surface. Conclusions: Surgical excision of GP in combination with MMC and AMT, in refractory VKC, is a good treatment option with better clinical outcomes over a longer follow-up.

Use of Amniotic Membrane in MMC-Augmented Trabeculectomy: A Retrospective Comparative Study

Purpose

Amniotic membrane transplantation (AMT) has shown promising results as an antifibrotic agent in trabeculectomy. We aimed to evaluate the additional effect of AMT in MMC-augmented trabeculectomy.

Patients and Methods

This retrospective study analyzed the results of the first 12 postoperative months of glaucomatous eyes submitted to Moorfields Safer Surgery Trabeculectomy with MMC alone (non-AMT group) compared to MMC and AMT (AMT group). Both groups were compared in terms of intraocular pressure (IOP), number of antihypertensive medications and need for surgical reinterventions. Absolute and relative success rates 12 months after surgery were defined as IOP <18 mmHg, without and with the use of antihypertensive medications, respectively.

Results

The analysis included 51 eyes of 45 glaucoma patients (29 eyes in the non-AMT group and 22 in the AMT group). Mean IOP decreased from 24.72±5.11 mmHg and 26.86±10.62 mmHg preoperatively in non-AMT and AMT groups to 12.86±4.22 mmHg and 12.60±4.43 mmHg, respectively, at 12 months (p = 0.84). Postoperative number of medications decreased significantly in both groups. Absolute success was seen in 71% of non-AMT eyes and 55% of AMT eyes (p = 0.46), whereas relative success was obtained in 14% and 30%, respectively (p = 0.55). Reinterventions were needed in 28% of the eyes (11 bleb injection/needling and 4 Ahmed tube implantation) in the non-AMT group and in 27% of the AMT group (10 bleb injection/needling and 1 Ahmed tube implantation) (p = 0.89).

Conclusion

Trabeculectomy combined with MMC and AMT did not show better results than trabeculectomy with MMC alone.

Systemic allergic dermatitis (systemic contact dermatitis) from pharmaceutical drugs: A review

The literature on systemic allergic dermatitis (SAD; also known as systemic contact dermatitis) is reviewed. Both topical drugs (from absorption through mucosae or skin) and systemic drugs (oral, parenteral, rectal) may be responsible for the disorder. The topical route appears to be rare with 41 culprit topical drugs found to cause SAD in 95 patients. Most reactions are caused by budesonide (especially from inhalation), bufexamac, and dibucaine. SAD from systemic drugs is infrequent with 95 culprit drugs found to cause SAD in 240 patients. The drugs most frequently implicated are mitomycin C, methylprednisolone (salt, ester), and hydrocortisone (salt). The largest group of culprit drugs consisted of corticosteroids (19%), being responsible for >30% of the reactions, of which nearly 40% were not caused by therapeutic drugs, but by drug provocation tests. The most frequent manifestations of SAD from drugs are eczematous eruptions (scattered, widespread, generalized, worsening, reactivation), maculopapular eruptions, symmetrical drug-related intertriginous and flexural exanthema (SDRIFE [baboon syndrome]) and widespread erythema or erythroderma. Therapeutic systemic drugs hardly ever cause reactivation of previously positive patch tests and infrequently of previous allergic contact dermatitis. The pathophysiology of SAD has received very little attention. Explanations for the rarity of SAD are suggested.

A SPIDR homozygous nonsense pathogenic variant in isolated primary ovarian insufficiency with chromosomal instability

Primary ovarian insufficiency (POI), affecting 1% of women under 40 years is a public health problem. Genes involved in meiosis/DNA repair were recently shown to be the leading family of associated causal genes, some of them also cause tumors/cancers. Here, using targeted next-generation sequencing in an Indian POI patient with primary amenorrhea and streak ovaries, we identified a novel homozygous nonsense variant in exon 7 of SPIDR (KIAA0146) c.814C > T, R272*, predicted to lead a nonsense-mediated mRNA decay. SPIDR was recently identified by in vitro assays as an auxiliary protein interacting with RAD51 and BLM, two major proteins involved in genome stability. Consistent with alteration of the RAD51 pathway, we observed a strong increase in mitomycin C-induced DNA breaks and aberrant metaphases in the patient's cells compared to a control. However, sister chromatid exchanges were normal in contrast to the sharp increase characteristic of the BLM pathway. This is the first evidence of chromosomal instability associated with a SPIDR molecular defect, which supports the role of SPIDR in double-stranded DNA damage repair in vivo in humans and its causal role in POI. Our study increases knowledge on the SPIDR function and has broad implications in the management of such patients.

Development of Mitomycin C-Loaded Nanoparticles Prepared Using the Micellar Assembly Driven by the Combined Effect of Hydrogen Bonding and π-π Stacking and Its Therapeutic Application in Bladder Cancer

Micelle is mainly used for drug delivery and is prepared from amphiphilic block copolymers. It can be formed into an obvious core-shell structure that can incorporate liposoluble drugs. However, micelles are not suitable for the encapsulation of water-soluble drugs, and it is also difficult to maintain stability in the systemic circulation. To solve these problems, a type of polymer material, Fmoc-Lys-PEG and Fmoc-Lys-PEG-RGD, was designed and synthesized. These copolymers could self-assemble into micelles driven by π-π stacking and the hydrophobic interaction of 9-fluorenylmethoxycarbony (Fmoc) and, at the same time, form a framework for a hydrogen-bonding environment in the core. Mitomycin C (MMC), as a water-soluble drug, can be encapsulated into micelles by hydrogen-bonding interactions. The interaction force between MMC and the polymers was analyzed by molecular docking simulation and Fourier transform infrared (FTIR). It was concluded that the optimal binding conformation can be obtained, and that the main force between the MMC and polymers is hydrogen bonding. Different types of MMC nanoparticles (NPs) were prepared and the physicochemical properties of them were systematically evaluated. The pharmacodynamics of the MMC NPs in vitro and in vivo were also studied. The results show that MMC NPs had a high uptake efficiency, could promote cell apoptosis, and had a strong inhibitory effect on cell proliferation. More importantly, the as-prepared NPs could effectively induce tumor cell apoptosis and inhibit tumor growth and metastasis in vivo.

Comparison of bleb morphology by anterior segment optical coherence tomography and clinical outcome after phacotrabeculectomy with mitomycin C or Ologen implant

Purpose:

To compare the bleb morphology by Anterior Segment Optical Coherence Tomography (ASOCT) and clinical outcome after Phacotrabeculectomy with either mitomycin C or Ologen implant.

Methods:

In a prospective interventional active controlled study, 93 patients aged 18 years and above underwent phacotrabeculectomy with either mitomycin C (53 eyes) or ologen implant (40 eyes), followed up for 12 months. The primary outcome measure was to note the evolution of bleb morphology by ASOCT in the two groups over 12 months. Secondary outcome measures were mean IOP, reduction in the need for anti-glaucoma medications, and complications seen in the two groups.

Results:

All parameters in the two groups were comparable preoperatively (P>0.05). Best corrected visual acuity at 12 months was 0.38±0.27 in mitomycin group and 0.31±0.23 in ologen group (P=0.151). Post-operative IOP at 12 months was 14.09±3.1mmHg (95%CI 13.22-14.97) in mitomycin group, and 13.25±2.5 mmHg (95%CI 12.40-14.30) in ologen group (P=0.254).The mean number of medications was 0.36±0.68 in mitomycin group and 0.38+/-0.70 in ologen group at 12 months (P=0.91). Overall success was achieved in 98.1 % of patients in mitomycin group and 90 % of patients in ologen group at 12 months. No major sight-threatening complications were noted in any group. AS-OCT imaging at 12 months showed multiform reflectivity with multiple large cystic spaces in both groups, with good IOP control.

Conclusion:

Phacotrabeculectomy using Mitomycin C and Ologen implant resulted in similar morphologic and functioning blebs at one year with comparable efficacy in controlling intraocular pressure.

Aberrometric, Keratometric, and Visual Outcomes After Trans-Epithelial Topography-Guided Phototherapeutic Keratectomy for the Treatment of Irregular Corneas

Purpose

To assess the safety, aberrometric and keratometric changes, and stability of trans-epithelial topography-guided phototherapeutic keratectomy (TE-TG-PTK) with mitomycin C (MMC) using the ALLEGRO Topolyzer platform for the treatment of irregular astigmatism.

Methods

This is a retrospective case series including 57 eyes that underwent TE-TG-PTK + MMC using the ALLEGRO Topolyzer platform for the treatment of irregular astigmatism. CDVA, manifest refraction (MR), keratometry readings, and aberrometry readings were analyzed at 1, 3, 6, and 12 months.

Results

Causes of corneal irregularity included non-infectious leucoma (n=23), infectious leucoma (n=7), adenoviral keratitis (n=20), corneal haze (n=2), post-penetrant keratoplasty (PKP) (n=1), and others (n=4). Overall, 76% of the eyes (n=40) gained lines of vision; patients gained 1, and 2 or more lines of vision in 76%, and 38% of cases, respectively. Only 1 patient (2%) lost 5 lines of vision. Mean preoperative CDVA (LogMAR) was 0.37 ±0.31 and improved to 0.14 ±0.18 (p<0.001) at final follow-up (12 months). CDVA remained unchanged in 10 eyes (21%). No significant changes were observed in mean keratometry (Kmean) and keratometric astigmatism readings. Regarding aberrometry, only changes in coma proved to be significant 6 months after surgery (P<0.01). No intraoperative/postoperative complications were reported.

Conclusion

At final follow-up, significant improvements were observed in CDVA and coma. TE-TG-PTK + MMC proved to be an effective and safe procedure for the treatment of corneal irregular astigmatism due to several causes.

Mitomycin C for the prevention of corneal haze in photorefractive keratectomy: a meta-analysis and trial sequential analysis

PURPOSE

To evaluate the anti-haze effect and visual outcome after intraoperative mitomycin C (MMC) use during photorefractive keratectomy (PRK) in myopia or myopic astigmatism patients.

METHODS

We searched in PubMed, EMBASE, Cochrane Library and Google Scholar comprehensively to obtain studies comparing the clinical effects after PRK with and without MMC published until February 2020. Meta-analysis of primary outcome (corneal haze rate) and secondary outcomes [predictability, efficacy, safety and corneal endothelial cell density (ECD)] were conducted. We used trial sequential analysis (TSA) in an effort to collect firm evidence supporting our conclusion.

RESULTS

Of the included 11 randomized controlled trials, five cohort and one case-control studies, 3536 eyes (2232 and 1304 in the MMC and control groups, respectively) were enrolled for meta-analysis. The TSA disclosed strong evidence of decline in corneal haze rate in the MMC group compared with that of the control group. In the subgroup analysis of duration, MMC seemed to reduce corneal haze rate in early-onset and late-onset haze. Predictability of refraction and visual acuity were greater in the MMC groups, not significantly though. The proportion of patients losing at least two lines of best corrected visual acuity postoperatively in the MMC groups was lower than that in the control groups. The corneal postoperative ECD showed no significant difference between the MMC and control groups.

CONCLUSION

Our meta-analysis revealed that MMC is an important anti-haze agent in PRK for reducing both early- and late-onset haze and can also help improving predictability of refraction and subjective postoperative visual acuity.

Long-term outcomes of blebs repaired with scleral patch graft and conjunctival advancement in late-onset leak post-trabeculectomy

Purpose:

To report long-term outcomes in eyes that developed late-onset bleb leak post trabeculectomy, with or without hypotony and/or maculopathy, due to a scleral melt/fistula and who required a scleral patch graft and conjunctival advancement for repair.

Methods:

Retrospective, non-comparative, interventional case series over a decade (2010–2019), presenting with late bleb leak post-filtration-surgery. All cases required a scleral patch graft and conjunctival advancement for management via a standard technique, performed by an experienced glaucoma surgeon.

Results:

A total of 18 eyes were included. Mean age was 51.5 ± 10.2 years (95% CI [46.4–56.7]) and were followed up after repair for 52.4 ± 26.9 months, 95%CI [39.1–65.8]. 66.7% eyes (n = 12) had IOP ≦6 mmHg and also had hypotony maculopathy. None of the eyes presented with blebitis. 44.5% (n = 8) eyes underwent phacoemulsification as significant cataract was present. LogMAR best-corrected visual acuity (BCVA) was 0.8 ± 0.7 (95% CI [0.4–1.1]) prior to intervention and improved to 0.4 ± 0.6 (95% CI[0.1–0.6], P = 0.004). 22.3% (n = 4) eyes had persistent choroidal folds but BCVA was improved. Mean pre-intervention intraocular pressure (IOP) was 6.3 ± 3.8 mmHg (95% CI 4.4–8.2]) which increased to 12.1 ± 2.9 mmHg (95%CI[10.6–13.5], (P < 0.001). 27.8% (n = 5) eyes needed laser suture lysis post repair to control IOP; two needed further surgical intervention. Number of anti-glaucoma medications at last follow-up was 0.4 ± 0.9 (95% CI [−0.1–0.8], P = 0.09). No serious complications were encountered.

Conclusion:

Scleral patch graft and conjunctival advancement is a useful technique for repair of a scleral fistula post-filtering surgery, and this is recommended not only for the restoration of anatomy for prevention of infection and control of IOP, but also for visual rehabilitation.