[Mitomycin C Treatment of Stromal Layers Enhances the Support of In Vitro Hematopoiesis in Co-Culture Systems]

A study was made of the effect that mitomycin C (MitC) treatment of stromal layers of NIH 3T3 cells expressing Jagged1, a ligand of the Notch receptor, exerts on the growth of hematopoietic Lin(-) mouse bone marrow cells in a co-culture system. MitC treatment of stromal cells significantly increased the number of hematopoietic cells and the frequency of colony-forming cells in stromal co-cultures. Transcriptome analysis of control and MitC-treated stromal cell samples was performed by differential RNA sequencing, and genes downregulated by MitC treatment were predominantly associated with the control of cell proliferation, the cell cycle, chromosome segregation, and DNA metabolism. Induction of key hematopoietic cytokines by MitC was not detected by the transcriptome analysis and was therefore not a main factor in the activation of hematopoiesis on the treated stroma. At the same time, the set of the genes most strongly upregulated by MitC treatment is enriched in the genes for cytokines, growth factors, and cell surface proteins, which presumably contribute to enhanced hematopoiesis support on the MitC-treated stroma. Products of some of these genes have been implicated in expansion of hematopoietic stem/progenitor cells in vitro or in vivo.

CSN7B defines a variant COP9 signalosome complex with distinct function in DNA damage response

Mammalian COP9 signalosome (CSN) exists as two variant complexes containing either CSN7A or CSN7B paralogs of unknown functional specialization. Constructing knockout cells, we found that CSN7A and CSN7B have overlapping functions in the deneddylation of cullin-RING ubiquitin ligases. Nevertheless, CSN^CSN7B has a unique function in DNA double-strand break (DSB) sensing, being selectively required for ataxia telangiectasia mutated (ATM)-dependent formation of NBS1^S343p and γH2AX as well as DNA-damage-induced apoptosis triggered by mitomycin C and ionizing radiation. Live-cell microscopy revealed rapid recruitment of CSN7B but not CSN7A to DSBs. Resistance of CSN7B knockout cells to DNA damage is explained by the failure to deneddylate an upstream DSB signaling component, causing a switch in DNA repair pathway choice with increased utilization of non-homologous end joining over homologous recombination. In mice, CSN7B knockout tumors are resistant to DNA-damage-inducing chemotherapy, thus providing an explanation for the poor prognosis of tumors with low CSN7B expression.

Post-Transurethral Resection of Bladder Tumor Bladder Perforation Resulting in Mitomycin C Extravasation, Pudendal Neuralgia, and Ureterohydronephrosis

Background: Mitomycin C (MMC) extravasation after transurethral resection of bladder tumor (TURBT) is a rare and highly morbid complication. Management of these cases may require a multidisciplinary approach with strategies ranging from conservative management to surgical intervention. Case Presentation: We present a 48-year-old woman who received a TURBT for a 5 mm bladder tumor. Procedure was uneventful and no bladder perforation was noticed. A single dose of instillation of MMC was performed after surgery resulting in extravasation, consequent ipsilateral pudendal neuralgia, and ureterohydronephrosis. Treatment included a second TURBT, Double-J stent placement, and multiple pain management schemes. After 8 months the patient had complete resolution of pain and ureterohydronephrosis. Conclusion: Perioperative chemotherapy is the standard of care in low-risk bladder cancer. Extravasation of MMC, although rare, can produce severe complications, sometimes irreversible. Other treatment options, such as gemcitabine, are less frequently used despite being less irritant and having similar efficacy. Further studies are needed to compare single-dose instillation regimens.

Comparison of the Efficacy and Safety of Trabeculectomy with Mitomycin C According to Concentration: A Prospective Randomized Clinical Trial

(1) Background: Mitomycin C (MMC) is commonly used during trabeculectomy. However, there is no consensus on which concentration should be used. We aimed to compare the efficacy and safety of 0.2 mg/mL and 0.4 mg/mL of MMC in eyes undergoing trabeculectomy. (2) Methods: Thirty-six eyes (36 glaucoma patients) were randomized to undergo a trabeculectomy with 0.2 mg/mL or 0.4 mg/mL of MMC. The success rate was evaluated according to three criteria: (A) intraocular pressure (IOP) ≤ 18 mmHg and IOP reduction ≥ 20%; (B) IOP ≤ 15 mmHg and IOP reduction ≥ 25%; (C) IOP ≤ 12 mmHg and IOP reduction ≥ 30%. Cox’s proportional hazard model was used to identify the predictive factors for failure. Immunohistochemical procedures for matrix metalloproteinase (MMP) were performed on Tenon’s tissue. Bleb morphology was evaluated. Safety was assessed based on the incidence of complications. (3) Results: Of the 36 eyes, 19 underwent trabeculectomy with 0.2 mg/mL of MMC and 17 with 0.4 mg/mL. The success rates were 75%, 67%, and 47% at 6 months for criteria A, B, and C, respectively. There were no significant differences between the two groups. High MMP-9 staining and low preoperative IOP were associated with failure (hazard ratio (HR), 5.556; p = 0.033, and HR, 0.936; p = 0.033). Complications included hypotony in two eyes (6%), hyphema in one eye (3%), and choroidal detachment in one eye (3%). (4) Conclusions: Trabeculectomy with 0.2 mg/mL and 0.4 mg/mL of MMC showed similar IOP-control effects to those recorded in previous studies, along with a low rate of complications. There was no significant difference in efficacy or safety between the 0.2 mg/mL and 0.4 mg/mL MMC groups.

Mitomycin C induces pulmonary vascular endothelial-to-mesenchymal transition and pulmonary veno-occlusive disease via Smad3-dependent pathway in rats

BACKGROUND AND PURPOSE

Pulmonary veno-occlusive disease (PVOD) is a rare disease characterized by the obstruction of small pulmonary veins leading to pulmonary hypertension. However, the mechanisms underlying pulmonary vessel occlusion remain largely unclear.

EXPERIMENTAL APPROACH

A mitomycin C (MMC)-induced PVOD rat model was used as in vivo animal model, and primarily cultured rat pulmonary microvascular endothelial cells (PMVECs) were used as in vitro cell model.

KEY RESULTS

Our data suggested an endothelial-to-mesenchymal transition (EndoMT) may be present in the pulmonary microvessels isolated from either PVOD patients or MMC-induced PVOD rats. In comparison to the control vessels, vessels from both PVOD patients and PVOD rats had co-localized staining of specific endothelial marker von Willebrand factor (vWF) and mesenchymal marker α-smooth muscle actin (α-SMA), suggesting the presence of cells that co-express endothelial and mesenchymal markers. In both the lung tissues of MMC-induced PVOD rats and MMC-treated rat PMVECs there were decreased levels of endothelial markers (e.g. VE-cadherin and CD31) and increased mesenchymal markers (e.g. vimentin, fibronectin and α-SMA) were detected indicating EndoMT. Moreover, MMC-induced activation of the TGFβ/Smad3/Snail axis, while blocking this pathway with either selective Smad3 inhibitor (SIS3) or small interfering RNA (siRNA) against Smad3, dramatically abolished the MMC-induced EndoMT. Notably, treatment with SIS3 remarkably prevented the pathogenesis of MMC-induced PVOD in rats.

CONCLUSIONS AND IMPLICATIONS

Our data indicated that targeted inhibition of Smad3 leads to a potential, novel strategy for PVOD therapy, likely by inhibiting the EndoMT in pulmonary microvasculature.

Clinical effect of mitomycin C combined with operation in the treatment of hyperplastic scar of auricle

OBJECTIVES

To observe the clinical effect and recurrence rate of mitomycin C combined with operation in the treatment of hyperplastic scar of auricle with different diameters.

METHODS

A total of 53 patients (67 ears) collected from January 2011 to June 2019 were randomly divided into a combined treatment group (31 ears) and a control group (36 ears). The recurrence rate was observed from one year to three years after operation.

RESULTS

The recurrence rate was 52.8% in the control group and 16.1% in the combined treatment group, respectively. For the hyperplastic scar of auricle with diameter from >1.0 cm to 3.0 cm, the recurrence rate was significantly lower in the combined treatment group than that in the control group (χ²=10.804, P<0.05). But there was no significant difference for the hyperplastic scar of auricle with diameter less than 1.0 cm or more than 3.0 cm (both P>0.05).

CONCLUSIONS

Mitomycin C combined with surgery can significantly reduce or delay the recurrence rate of middle diameter of hyperplastic scar of auricle, but it does not affect the hyperplastic scar of auricle with too large or too small diameter.

Intraocular mitomycin C use in the treatment and prophylaxis of proliferative vitreoretinopathy in severe traumatic retinal detachments

PURPOSE

To evaluate the anatomic and visual outcomes of a new intraocular mitomycin c (MMC) application technique in the treatment of severe traumatic retinal detachment (RD) with advance proliferative vitreoretinopathy (PVR).

METHODS

The records of 15 eyes of 14 patients who underwent vitreoretinal surgery and intraoperative MMC application were reviewed retrospectively.

SURGICAL TECHNIQUE

After performing complicated vitreoretinal surgical procedures (Pars plana vitrectomy, PVR membrane stripping, large retinotomy/retinectomies and intraocular foreign body removal if found etc. . .) retina was attached with perfluorocarbon liquid (PFCL) and partial fluid-air exchange. Endolaser was performed. PFCL was removed to the posterior borders of retinochoroidal wounds, breaks or retinectomy sites. The remaining PFCL was enough to cover and prevent MMC contact with the posterior vital structures including optic disc, macula and underlying RPE and major vascular arcades. Ciliary epithelium and other anterior segment structures were protected from MMC contact with the use of air in the rest of the eye. Then, a 10 µg/mL concentrated MMC solution was carefully injected above the PFCL bubble until it covered PVR or potential areas of PVR development and removed after 60 s. Finally, the remaining PFCL was removed and all eyes were filled with silicone oil. The patients were followed at least 6 months after silicone oil removal. Visual and anatomic outcomes were determined during follow-up period.

RESULTS

The mean follow-up time was 19.6 ± 6 months (range 12-27 months). About 100% retinal attachment was achieved with one vitreoretinal surgery during the follow-up period. PVR was not detected around the retinal breaks or retinotomy sites in any eye. Limited macular epiretinal membrane was detected in two eyes and subsequently peeled during silicone oil removal. Preoperative visual acuities were hand motions in seven eyes and light perception in eight eyes. Nine of 15 eyes had a visual acuity of ⩾0.1 during the follow-up period. The mean preoperative visual acuity was logMAR 2.16 ± 0.15 and postoperative visual acuity was 0.80 ± 0.50 (p = 0.001). There were no additional complications related to intraoperative MMC use during follow-up period.

CONCLUSION

Temporary intraocular MMC use in vitreoretinal surgery yielded good anatomic and visual outcomes after the treatment of traumatic RDs with PVR or those with high risk of PVR development. Furthermore, MMC application appeared to prevent further PVR development after vitreoretinal surgery.

Repeated phototherapeutic keratectomy (PTK) followed by PTK with photorefractive keratectomy for anterior granular corneal dystrophy

Two preteen siblings with the anterior-stromal variant of granular corneal dystrophy type 1 underwent multiple phototherapeutic keratectomies (PTK) (due to recurrences of the dystrophy) with progressively increasing hyperopia after each procedure. The last procedure performed was an additional photorefractive keratectomy along with the PTK which led to a decrease in the hyperopia with better refractive outcomes. The addition of mitomycin C may have led to a delay in the recurrence of the dystrophy.

Outcomes and complications of Hyperthermic IntraVesical Chemotherapy using mitomycin C or epirubicin for patients with non-muscle invasive bladder cancer after bacillus Calmette-Guérin treatment failure

Introduction

Chemohyperthermia is a feasible option in BCG (bacillus Calmette-Guérin) failure patients who desire bladder preservation. We aimed to assess outcomes and complications of chemohyperthermia using mitomycin C (MMC) or epirubicin (EPI).

Material and methods

From March 2017 to February 2020, 103 BCG failure or intolerance patients with high-risk NMIBC (non-muscle invasive bladder cancer) underwent a hyperthermic intravesical chemotherapy (HIVEC) regimen. Five patients did not complete at least 5 instillations and were excluded from analysis. MMC was used in 72 out of 98 patients (Group A) while EPI was used in 26 patients (Group B). Response to HIVEC, predictive factors for treatment outcome and the disease-free survival (DFS) were defined as primary endpoints. The complications of chemohyperthermia were assessed as a secondary endpoint.

Results

No significant differences were found in recurrence and progression after induction course between Groups A and B. Kaplan-Meier disease-free survival was 22.61 months in Group A and 21.93 in Group B. The log-rank test showed no statistically significant difference between the two curves (p = .627). In the multivariate analysis, patients with tumor size ≥3 cm (p = .029), recurrence rate >1/year (p = .034), concomitant carcinoma in situ (CIS) during transurethral resection of bladder (TURB) (p = .039) and BCG-unresponsive status (p = .048) were associated with a worse response to chemohyperthermia. The use of MMC or EPI did not influence the response to treatment (p = .157). A slightly significant higher rate of overall complications (p = .0488) was observed in Group B. A significantly higher rate of Grade 3 frequency/urgency (p = .0064) contributed to this difference. The use of EPI was the only independent factor associated with severe urinary frequency/urgency (p = .017). No patients experienced Grade 4/5 adverse events.

Conclusions

HIVEC can be considered a feasible option in BCG failure/intolerant NMIBC patients, avoiding or postponing radical cystectomy in some particular subclasses of patients.

Genetic Variants in DNA Repair Pathways as Potential Biomarkers in Predicting Treatment Outcome of Intraperitoneal Chemotherapy in Patients With Colorectal Peritoneal Metastasis: A Systematic Review

Background

The introduction of cytoreductive surgery (CRS) followed by hyperthermic intraperitoneal chemotherapy (HIPEC) with either oxaliplatin or mitomycin C for patients with colorectal peritoneal metastasis (CPM) has resulted in a major increase in overall survival. Nonetheless, despite critical patient selection, the majority of patients will develop recurrent disease within one year following CRS + HIPEC. Therefore, improvement of patient and treatment selection is needed and may be achieved by the incorporation of genetic biomarkers. This systematic review aims to provide an overview of genetic biomarkers in the DNA repair pathway that are potentially predictive for treatment outcome of patients with colorectal peritoneal metastases treated with CRS + HIPEC with oxaliplatin or mitomycin C.

Methods

A systematic review was conducted according to the PRISMA guidelines. Given the limited number of genetic association studies of intraperitoneal mitomycin C and oxaliplatin in patients with CPM, we expanded the review and extrapolated the data from biomarker studies conducted in colorectal cancer patients treated with systemic mitomycin C– and oxaliplatin-based chemotherapy.

Results

In total, 43 papers were included in this review. No study reported potential pharmacogenomic biomarkers in patients with colorectal cancer undergoing mitomycin C–based chemotherapy. For oxaliplatin-based chemotherapy, a total of 26 genetic biomarkers within 14 genes were identified that were significantly associated with treatment outcome. The most promising genetic biomarkers were ERCC1 rs11615, XPC rs1043953, XPD rs13181, XPG rs17655, MNAT rs3783819/rs973063/rs4151330, MMR status, ATM protein expression, HIC1 tandem repeat D17S5, and PIN1 rs2233678.

Conclusion

Several genetic biomarkers have proven predictive value for the treatment outcome of systemically administered oxaliplatin. By extrapolation, these genetic biomarkers may also be predictive for the efficacy of intraperitoneal oxaliplatin. This should be the subject of further investigation.

[Lamellar keratoplasty in the management of recurrent pterygium]

As it is known, the main problem of surgical treatment of pterygium is associated with high risk of recurrence. Quite a number of surgical techniques now exist, all aimed at pterygium removal and only differing in the method of conjunctival closure following the excision. Due to relatively low recurrence rates, conjunctival or conjunctival-limbal autografts are currently the 'gold standard' of pterygium surgery. The frequency of recurrence is also insignificant in peripheral anterior lamellar keratoplasty, which is rarely performed due to its complexity and the need for donor cornea. However, it is considered to be the method of choice in cases of repeated recurrence as well as in patients with high pterygium activity. This article describes a clinical case of a massive recurrent pterygium (grade IV, activity level 3). The patient has had three previous surgeries (including conjunctival autotransplantation) that yielded no success. By performing large-diameter peripheral anterior lamellar keratoplasty in combination with adjuvant therapy (intraoperative mitomycin C and subconjunctival postoperative aflibercept injections), structural integrity of the cornea was finally restored without further recurrences and visual acuity was increased.

Injected Versus Sponge-Applied Mitomycin C (MMC) During Modified Trabeculectomy in New Zealand White Rabbit Model

Purpose

Mitomycin C is routinely applied during trabeculectomy surgeries to enhance bleb survival after glaucoma filtration surgery. The current approach involves placing cellulose sponges soaked in mitomycin C at a standard concentration onto bare sclera for a predetermined duration, which varies among surgeons. The purpose of this study was to compare the effects of sponge-applied versus intra-Tenon injection of mitomycin C during modified trabeculectomy.

Methods

Two groups of five New Zealand White rabbits underwent glaucoma filtration surgery with either preoperative intra-Tenon injection of mitomycin C or intraoperative application of mitomycin C using a cellulose sponge. Postoperative intraocular pressure was recorded weekly, and eyes were enucleated and sent for pathological examination and histological analysis.

Results

An intra-Tenon injection of mitomycin C resulted in decreased intraocular pressure measurements and bleb vascularity compared to the controls but increased levels compared to the sponge-applied group. Collagen deposition and cellularity were reduced and the goblet cell population was increased in the intra-Tenon injection group.

Conclusions

This study shows that an intra-Tenon injection can be an effective method for administering mitomycin C compared to the standard-of-care approach of mitomycin C being sponge applied onto bare sclera. Mitomycin C injection led to a greater reduction in intraocular pressure and inhibition of fibroblasts. The associated goblet cell population that can lead to increased mitomycin C toxicity-related morbidity was minimized with the intra-Tenon injection compared to the sponge-applied MMC treatment. Therefore, patients with ocular surface disease may benefit from an intra-Tenon injection.

Translational Relevance

This project provides a direct, qualitative assessment in an animal model of common techniques within glaucoma filtration surgery for drug delivery to improve surgical success.

Retrospective evaluation of two-year results with a filtering trabeculotomy in comparison to conventional trabeculectomy by exact matching

Background: To compare two-year results of a filtering trabeculotomy (FTO) to conventional trabeculectomy (TE) in open-angle glaucoma by exact matching.

Methods: 110 patients received an FTO and 86 a TE. FTO avoided the need for an iridectomy due to a preserved trabeculo-descemet window anterior to the scleral flap. TE employed a trabecular block excision and iridectomy. Mitomycin C was used in both. FTO and TE were exact matched by baseline intraocular pressure (IOP) and the number of glaucoma medications. Complete and qualified success (IOP ≤18 mmHg and IOP reduction ≥ 30%, with or without medication) were primary endpoints. IOP, visual acuity (BCVA), complications and intervention were secondary endpoints.

Results: 44 FTO were exact matched to 44 TE. The IOP baseline in both groups was 22.5±4.7 mmHg on 3±0.9 medications. At 24 months, complete success was reached by 59% in FTO and 66% in TE, and qualified success by 59% in FTO and 71% in TE. In FTO, IOP was reduced to 12.4±4.3 mmHg at 12 months and 13.1±4.1 mmHg at 24 months. In TE, IOP was 11.3±2.2 mmHg at 12 months and 12.0±3.5 mmHg at 24 months. Medications could be reduced at 24 months to 0.6±1.3 in FTO and 0.2±0.5 in TE. There were no significant differences between the two groups in IOP, medications, complications or interventions at any point.

Conclusion: Modifying aqueous flow through a limited trabeculotomy in FTO yielded clinical outcomes similar to traditional TE but allowed to avoid an iridectomy.

Characteristics and Long-term Outcomes of Pulmonary Venoocclusive Disease Induced by Mitomycin C

BACKGROUND

Pulmonary venoocclusive disease (PVOD) is an uncommon form of pulmonary hypertension (PH) predominantly characterized by pulmonary vein and capillary involvement. An association between chemotherapy, in particular mitomycin C (MMC), and PVOD has been reported.

RESEARCH QUESTION

What are the characteristics of MMC-induced PVOD, and what is the prognosis for patients with MMC-induced PVOD?

STUDY DESIGN AND METHODS

We report the clinical, functional, radiologic, and hemodynamic characteristics at diagnosis and outcomes of patients with PVOD from the French PH Registry after exposure to MMC. The results are expressed as the median (minimum-maximum).

RESULTS

From June 2011 to December 2018, 17 incident cases of MMC-induced PVOD were identified. At diagnosis, these patients had severe clinical and functional impairment, with 12 patients having a New York Heart Association (NYHA) functional class of III or IV and a 6-min walk distance of 220 (0-465) m. Right heart catheterization confirmed severe precapillary PH with a mean pulmonary artery pressure of 38 (30-52) mm Hg, a cardiac index of 2.2 (1.5-4) L/(min × m²), and pulmonary vascular resistance of 8.3 (5.1-14.5) Wood units. The diffusing capacity of the lungs for carbon monoxide was markedly decreased at 31% (20%-51%) of the theoretical values associated with severe hypoxemia. MMC was withdrawn for all patients, and 14 patients received specific pulmonary arterial hypertension (PAH) therapies. Among these patients, mild but statistically insignificant improvements were observed in NYHA functional class (P = .10), 6-min walk distance (P = .09), and pulmonary vascular resistance (-4.7 Wood units; P = .052) at reassessment (median delay of 4.8 months). Three patients experienced pulmonary edema requiring the cessation or reduction of PAH treatment. The median overall survival was 20 months, and the 6-, 12-, and 24-month survival rates were 76%, 58%, and 18%, respectively.

INTERPRETATION

PVOD after MMC treatment is a rare but life-threatening complication associated with a poor prognosis despite MMC withdrawal and PAH-specific therapy.

Randomized Study of Postoperative Single Intravesical Instillation With Pirarubicin and Mitomycin C for Low-risk Bladder Cancer

BACKGROUND

To assess the prophylactic efficacy of postoperative single intravesical instillation with pirarubicin (THP) and mitomycin C (MMC) for low-risk non-muscle-invasive bladder cancer (NMBC).

PATIENTS AND METHODS

A total of 103 clinically low-risk NMBC patients were preoperatively randomized into either THP (n=49) or MMC (n=54) groups. The primary endpoint was recurrence-free survival.

RESULTS

The median follow-up periods of the THP and MMC groups were 955 and 1008 days, respectively (p=0.76). Twelve patients (24.5%) in the THP group and 7 (13%) in the MMC group had bladder cancer recurrences. The two-year recurrence-free survival of the THP group and the MMC group was 77.8% and 86.4%, respectively (p=0.20). Neither groups had severe toxicity.

CONCLUSION

In low-risk NMBC, the prophylactic effect against postoperative single intravesical instillation with THP was not superior to that with MMC.

Can postoperative dexamethasone nanoparticle eye drops replace mitomycin C in trabeculectomy?

PURPOSE

Compare (a) nonmitomycin C (MMC) trabeculectomy and 1.5% dexamethasone nanoparticle (DexNP) eye drops postoperatively with (b) trabeculectomy with MMC and Maxidex^® eye drops postoperatively.

METHODS

Randomized prospective single masked clinical trial with 20 patients with primary open-angle glaucoma undergoing primary trabeculectomy. The study group consisted of 10 patients without MMC intraoperatively and postoperative DexNP eye drops, and the control group consisted of 10 patients treated with MMC intraoperatively and postoperative Maxidex^® . The drops were tapered out over 8 weeks. The main outcome measures were as follows: rates of complete success, that is intraocular pressure (IOP) within target pressures at different time-points without IOP-lowering medication, or reoperation. Secondary outcome measures included the following: relative success rate (with IOP-lowering medications), number of glaucoma medications and reoperations. Patients were followed for 36 months.

RESULTS

Both groups showed similar postoperative course and IOP reduction. Intraocular pressures (IOPs) in the DexNP group and in the control group were 25.6 and 24.4 mmHg, respectively, at baseline. Intraocular pressures (IOPs) were reduced to 13.2 and 14.5 mmHg at 12 months, 11.7 and 12.6 mmHg at 24 months and 11.7 and 12.1 mmHg at 36 months, respectively. There were no statistically significant differences between the groups in absolute (p = 0.36) or relative (p = 1.0) success rates, number of medications (p = 0.71) or reoperations (p = 1.0) between the groups at any time-point.

CONCLUSIONS

DexNP eye drops are effective postoperative treatment following trabeculectomy. The potent anti-inflammatory and antifibrotic effect of DexNP may offer an alternative to mitomycin C in glaucoma surgery.

Electro-mediated drug administration of mitomycin C in preventing non-muscle-invasive bladder cancer recurrence and progression after transurethral resection of the bladder tumour in intermediate- and high-risk patients

Objective

To evaluate the effectiveness of electro-mediated drug administration of mitomycin C (EMDA/MMC) after transurethral resection of the bladder tumour (TURBT) in preventing non-muscle-invasive bladder cancer (NMIBC) recurrence and progression and to explore clinical and demographic factors associated with treatment response.

Patients and methods

Between April 2016 and August 2019, 112 patients diagnosed with intermediate- or high-risk NMIBC underwent a TURBT followed by an EMDA/MMC treatment. The percentage of treatment responders and progression-free survivors at 3 and 6 months were evaluated.

Results

Follow-up data were available for 101 patients (90%) at 3 months and 92 (82%) at 6 months. Response rates to EMDA/MMC treatment were 85% at 3 months and 75% at 6 months, and progression-free rates were 94% and 90%, respectively. No statistically significant differences were seen between intermediate- and high-risk patients. A higher risk of tumour recurrence and progression was associated with previous Bacillus Calmette–Guérin (BCG) failure. According to the Clavien–Dindo classification, only low-grade complications were observed.

Conclusions

EMDA/MMC after TURBT was associated with high response and progression-free rates at 3 and 6 months, with only low-grade adverse events. These results confirm the efficacy and safety of EMDA/MMC as a therapeutic option for both intermediate- and high-risk patients. However, patients with BCG failure responded poorly to EMDA/MMC.

Abbreviations: ACCI: age-adjusted Charlson Comorbidity Index; CHT: chemohyperthermia; CIS: carcinoma in situ; EMDA: electro-mediated drug administration; EORTC: European Organisation for Research and Treatment of Cancer; IQR: interquartile range; (N)MIBC: (non-)muscle-invasive bladder cancer; MMC: mitomycin C; OR, odds ratio; TURBT: transurethral resection of the bladder tumour

Suppression of non-homologous end joining does not rescue DNA repair defects in Fanconi anemia patient cells

Severe cellular sensitivity and aberrant chromosomal rearrangements in response to DNA interstrand crosslink (ICL) inducing agents are hallmarks of Fanconi anemia (FA) deficient cells. These phenotypes have previously been ascribed to inappropriate activity of non-homologous end joining (NHEJ) rather than a direct consequence of DNA ICL repair defects. Here we used chemical inhibitors, RNAi, and Clustered Regularly Interspaced Short Palindromic Repeat (CRISPR)-Cas9 to inactivate various components of NHEJ in cells from FA patients. We show that suppression of DNA-PKcs, DNA Ligase IV, and 53BP1 is not capable of rescuing ICL-induced proliferation defects and only 53BP1 knockout partially suppresses the chromosomal abnormalities of FA patient cells.

Impact of Viral Lysis on the Composition of Bacterial Communities and Dissolved Organic Matter in Deep-Sea Sediments

Viral lysis is a main mortality factor for bacteria in deep-sea sediments, leading to changing microbial community structures and the release of cellular components to the environment. Nature and fate of these compounds and the role of viruses for microbial diversity is largely unknown. We investigated the effect of viruses on the composition of bacterial communities and the pool of dissolved organic matter (DOM) by setting up virus-induction experiments using mitomycin C with sediments from the seafloor of the Bering Sea. At the sediment surface, no substantial prophage induction was detected, while incubations from 20 cm below seafloor showed a doubling of the virus-to-cell ratio. Ultra-high resolution mass spectrometry revealed an imprint of cell lysis on the molecular composition of DOM, showing an increase of molecular formulas typical for common biomolecules. More than 50% of these compounds were removed or transformed during incubation. The remaining material potentially contributed to the pool of refractory DOM. Next generation sequencing of the bacterial communities from the induction experiment showed a stable composition over time. In contrast, in the non-treated controls the abundance of dominant taxa (e.g., Gammaproteobacteria) increased at the expense of less abundant phyla. Thus, we conclude that viral lysis was an important driver in sustaining bacterial diversity, consistent with the "killing the winner" model.

The role of mitomycin C and porcine extracellular matrix in phacotrabeculectomy

PURPOSE

To compare between mitomycin C alone, porcine extracellular matrix alone, and combined low dose mitomycin C with porcine extracellular matrix in term of efficacy and safety in phaco-trabeculectomy surgery.

STUDY DESIGN

Prospective comparative.

METHODS

Sixty eyes of 60 patients complaining of primary open angle glaucoma and cataract, undergoing phaco-trabeculectomy, were distributed into three groups: group I: surgery was augmented with mitomycin C, group II with porcine extracellular matrix, and group III with porcine extracellular matrix combined with low dose mitomycin C. Intraocular pressure was evaluated, postoperatively, at day 1, week 1, and 1, 3, 6, 9, and 12 months. Bleb vascularity, pre- and post-operative intraocular pressure lowering medications, success of IOP control and complications were also evaluated.

RESULTS

After 12 months, the mean preoperative intraocular pressure (mm Hg) improved from 30.85 ± 4.7, 33.8 ± 4.2, and 31.05 ± 5.4 mm Hg, in groups I, II, and III respectively, to 13.8 ± 4.7 (55.2%), 15.2 ± 4.8 (55%), and 13 ± 4.9 (58.1%) (p > 0.05). Success of IOP control, postoperative IOP lowering medications and complications were comparable (p > 0.05). Bleb vascularity was significantly different (p < 0.05).

CONCLUSION

Mitomycin C, porcine extracellular matrix and their combination are equally effective in phacotrabeculectomy.

Low Host Abundance and High Temperature Determine Switching from Lytic to Lysogenic Cycles in Planktonic Microbial Communities in a Tropical Sea (Red Sea)

The lytic and lysogenic life cycles of marine phages are influenced by environmental conditions such as solar radiation, temperature, and host abundance. Temperature can regulate phage infection, but its role is difficult to discern in oligotrophic waters where there is typically low host abundance and high temperatures. Here, we study the temporal variability of viral dynamics and the occurrence of lysogeny using mitomycin C in a eutrophic coastal lagoon in the oligotrophic Red Sea, which showed strong seasonality in terms of temperature (22.1–33.3 °C) and large phytoplankton blooms. Viral abundances ranged from 2.2 × 10⁶ to 1.5 × 10⁷ viruses mL⁻¹ and were closely related to chlorophyll a (chl a) concentration. Observed high virus-to-bacterium ratio (VBR) (4–79; 16 ± 4 (SE)) suggests that phages exerted a tight control of their hosts as indicated by the significant decrease in bacterial abundance with increasing virus concentration. Heterotrophic bacterial abundance also showed a significant decrease with increasing temperature. However, viral abundance was not related to temperature changes and the interaction of water temperature, suggesting an indirect effect of temperature on decreased host abundance, which was observed at the end of the summertime. From the estimated burst size (BS), we observed lysogeny (undetectable to 29.1%) at low percentages of 5.0% ± 1.2 (SE) in half of the incubations with mitomycin C, while it increased to 23.9% ± 2.8 (SE) when the host abundance decreased. The results suggest that lytic phages predominate, switching to a moderate proportion of temperate phages when the host abundance reduces.

Cosmetic Pterygium Surgery: Techniques and Long-Term Outcomes

Background

To demonstrate the long-term results of enhanced cosmetic pterygium surgery with extensive Tenonectomy, adjunctive fibrin-glued amniotic membrane transplantation (AMT), and mitomycin C (MMC).

Methods

Retrospective chart review of patients who had pterygium surgery with AMT and MMC between January 2001 to July 2017 and had completed at least 6 months of follow-up. Early and long-term postoperative cosmetic outcomes, recurrence rate, and complications were analyzed. Cosmetic outcomes were evaluated based on patient and surgeon reported outcome measures.

Results

The study was conducted on a total of 603 eyes of 578 patients (316 males, 262 females) with an average age of 52.9 ± 15.1 years. At post-op day 1, patients reported no discomfort and could not tell which eye had surgery based on patient reported subjective grading scales. Over an average follow-up period of 23.1 ± 35 months (range: 6–216 months), there was one pterygium recurrence (0.2%), eighteen granulomas (2.9%), one self-resolving scleral melt (0.2%), one correctable restricted ocular motility (0.2%), one pupil abnormality (0.2%), one dellen (0.2%) and one correctable upper lid abnormality (0.2%). Planned laser vision correction was used for residual corneal scar in eleven eyes (1.8%) as a staged refractive approach.

Conclusion

This study highlights an improved technique of an old concept of pterygium surgery that not only reduces the recurrence but also enhances cosmetic excellence and improves the quality of vision.

Management of Recurrent Pterygium with Severe Symblepharon Using Mitomycin C, Double Amniotic Membrane Transplantation, Cryopreserved Limbal Allograft, and a Conjunctival Flap

Purpose

The aim of this study was to evaluate the clinical outcomes of management of recurrent pterygium with severe symblepharon using mitomycin C, double amniotic membrane transplantation, cryopreserved limbal allograft, and a conjunctival flap.

Patients and Methods

This retrospective case series included 10 eyes of 10 patients with recurrent pterygium with severe symblepharon. Eight patients have diplopia in primary gaze. All patients underwent pterygium excision, application of mitomycin C (MMC), double amniotic membrane transplantation (AMT), cryopreserved limbal allograft (CLA) transplantation, and placement of a conjunctival flap. Outcome measures were visual acuity, astigmatism, and recurrence. Recurrence was defined as the presence of fibrovascular proliferative tissue crossing the limbus.

Results

The patients’ mean age was 73.8 years. The mean follow-up period was 3.0 years. The mean preoperative and postoperative best-corrected visual acuities (logMAR conversion) were 0.43 and 0.30, respectively. The mean preoperative and postoperative astigmatism were –3.89 diopters and –1.54 diopters, respectively, and there was a significant difference. No recurrence occurred in any of the eyes. Symblepharon was released in all eyes. Diplopia in primary gaze was resolved in all eyes.

Conclusion

Management of recurrent pterygium with severe symblepharon using MMC, double AMT, CLA, and a conjunctival flap was an effective treatment.

Topical chemotherapy with mitomycin C in a feline corneal squamous cell carcinoma

Case summary

A 9-year-old cat was presented with a right globe lesion of 6 months’ duration. A large pink elevated mass covering two-thirds of the right cornea was detected. The corneal mass was surgically removed by superficial keratectomy and diagnosed by histopathology as a squamous cell carcinoma (SCC). The surgical procedure led to a relatively transparent cornea, but recurrence was likely. To avoid relapse, 1 month after surgery three cycles of mitomycin C 0.04% eye drops were applied q8h for 15 days on/15 days off. No local or systemic side effects were seen, and no recurrence was detected after 1 year of follow-up. Topical mitomycin C was successfully used as adjuvant local chemotherapy agent and prevented relapses owing to its cytostatic effect.

Relevance and novel information

SCCs are relatively common in feline patients, especially in the non-pigmented extremities of the nose, ears and eyelids, but with the cornea being a rare location. They rarely metastasise and they seldom relapse locally after surgical excision. Surgical-free margins of 2 cm are advisable to prevent relapses. Corneal tumours are rare, as the cornea is avascular; corneal transparency is essential to assure clear vision. In corneal SCC this margin is impossible to achieve without enucleation. In the present report, surgical removal of the neoplasm was combined with topical administration of the anticancer drug mitomycin C and a good prognosis was obtained. This combined treatment may be an appropriate therapeutic option for feline corneal SCC.

Learning from the past: Mitomycin C use in trabeculectomy and its application in bleb-forming minimally invasive glaucoma surgery

Trabeculectomy has been performed since the mid-1960s and remains the gold standard for glaucoma surgery. Newer surgical options have evolved, collectively referred to as minimally invasive glaucoma surgeries. Despite producing large intraocular pressure decreases, full-thickness procedures into the subconjunctival space may be limited by fibrosis. Mitomycin C (MMC) and 5-fluorouracil have been in use with trabeculectomy with good evidence of significantly increased success at the cost, however, of an increased risk of complications. Off-label MMC application can be found in almost all clinical trials, including in combination with minimally invasive glaucoma surgeries. We explore current evidence for MMC use in trabeculectomy and how this may differ for minimally invasive glaucoma surgery devices and analyze the range of agents and doses that are used. Although we found that most studies could not show any correlation between MMC dosage and the surgical outcome, the success rates with the Xen® microshunt seemed to be higher when using 20 mcg of MMC than when using 10 mcg. Certain important methodological considerations make this hard to confirm definitively, and other factors such as placement of the device may play a more substantial role. For the PreserFlo® microshunt, preliminary data suggest higher success rates with higher MMC dosage at the cost of higher device-related adverse events and reoperations. Although the ideal dose still needs to be established, it seems very likely that MMC provides significant improvement in outcomes in bleb-forming minimally invasive glaucoma procedures.