Browsing by Subject "Mitomycin"

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    ItemOpen Access
    Atypical Fibroxanthoma of the Bulbar Conjunctiva.
    (Cornea, 2015-12) Shieh, Christine; Daluvoy, Melissa B; Ellington, Kenneth S; Proia, Alan D
    PURPOSE: To report a rare case of atypical fibroxanthoma (AFX) of the bulbar conjunctiva, and to compare it with previously published cases of conjunctival AFX. METHODS: A 37-year-old woman developed a growth on the bulbar conjunctiva of her left eye that increased in size and redness over 4 months and was associated with blurry vision in the left eye, occasional diplopia, irritation of the eye, and increasing tearing. The mass was surgically excised. RESULTS: Slit-lamp examination disclosed a highly vascularized conjunctival lesion with intact lustrous epithelium and a raised nodular edge encroaching on the nasal corneal limbus of the left eye. Pathological examination and immunohistochemistry were diagnostic of AFX. CONCLUSIONS: AFX of the conjunctiva is rare, with this being only the fifth example of this neoplasm reported at this site. Complete surgical excision is the most appropriate treatment option.
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    DNA adducts of decarbamoyl mitomycin C efficiently kill cells without wild-type p53 resulting from proteasome-mediated degradation of checkpoint protein 1.
    (Chem Res Toxicol, 2010-07-19) Boamah, Ernest K; Brekman, Angelika; Tomasz, Maria; Myeku, Natura; Figueiredo-Pereira, Maria; Hunter, Senyene; Meyer, Joel; Bhosle, Rahul C; Bargonetti, Jill
    The mitomycin derivative 10-decarbamoyl mitomycin C (DMC) more rapidly activates a p53-independent cell death pathway than mitomycin C (MC). We recently documented that an increased proportion of mitosene1-beta-adduct formation occurs in human cells treated with DMC in comparison to those treated with MC. Here, we compare the cellular and molecular response of human cancer cells treated with MC and DMC. We find the increase in mitosene 1-beta-adduct formation correlates with a condensed nuclear morphology and increased cytotoxicity in human cancer cells with or without p53. DMC caused more DNA damage than MC in the nuclear and mitochondrial genomes. Checkpoint 1 protein (Chk1) was depleted following DMC, and the depletion of Chk1 by DMC was achieved through the ubiquitin proteasome pathway since chemical inhibition of the proteasome protected against Chk1 depletion. Gene silencing of Chk1 by siRNA increased the cytotoxicity of MC. DMC treatment caused a decrease in the level of total ubiquitinated proteins without increasing proteasome activity, suggesting that DMC mediated DNA adducts facilitate signal transduction to a pathway targeting cellular proteins for proteolysis. Thus, the mitosene-1-beta stereoisomeric DNA adducts produced by the DMC signal for a p53-independent mode of cell death correlated with reduced nuclear size, persistent DNA damage, increased ubiquitin proteolysis and reduced Chk1 protein.
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    ItemOpen Access
    Heated Intravesical Chemotherapy: Biology and Clinical Utility.
    (The Urologic clinics of North America, 2020-02) Tan, Wei Phin; Longo, Thomas A; Inman, Brant A
    Non-muscle-invasive bladder cancer can be a challenging disease to manage. In recent years, hyperthermia therapy in conjunction with intravesical therapy has been gaining traction as a treatment option for bladder cancer, especially if Bacillus Calmette-Guerin might not be available. Trials of intravesical chemotherapy with heat are few and there has been considerable heterogeneity between studies. However, multiple new trials have accrued and high-quality data are forthcoming. In this review, we discuss the role of combined intravesical hyperthermia and chemotherapy as a novel approach for the treatment of bladder cancer.
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    Safety and efficacy of intravesical chemotherapy and hyperthermia in the bladder: results of a porcine study.
    (International journal of hyperthermia : the official journal of European Society for Hyperthermic Oncology, North American Hyperthermia Group, 2020-01) Tan, Wei Phin; Chang, Andrew; Brousell, Steven C; Grimberg, Dominic C; Fantony, Joseph J; Longo, Thomas A; Etienne, Wiguins; Spasojevic, Ivan; Maccarini, Paolo; Inman, Brant A

    Background

    Hyperthermia (heating to 43 °C) activates the innate immune system and improves bladder cancer chemosensitivity.

    Objective

    To evaluate the tissue penetration and safety of convective hyperthermia combined with intravesical mitomycin C (MMC) pharmacokinetics in live porcine bladder models using the Combat bladder recirculation system (BRS).

    Methods

    Forty 60 kg-female swine were anesthetized and catheterized with a 3-way, 16 F catheter. The Combat device was used to heat the bladders to a target temperature of 43 °C with recirculating intravesical MMC at doses of 40, 80, and 120 mg. Dwell-heat time varied from 30-180 min. Rapid necropsy with immediate flash freezing of tissues, blood and urine occurred. MMC concentrations were measured by liquid chromatography tandem-mass spectrometry.

    Results

    The Combat BRS system was able to achieve target range temperature (42-44 °C) in 12 mins, and this temperature was maintained as long as the device was running. Two factors increased tissue penetration of MMC in the bladder: drug concentration, and the presence of heat. In the hyperthermia arm, MMC penetration saturated at 80 mg, suggesting that with heating, drug absorption may saturate and not require higher doses to achieve the maximal biological effect. Convective hyperthermia did not increase the MMC concentration in the liver, heart, kidney, spleen, lung, and lymph node tissue even at the 120 mg dose.

    Conclusions

    Convective bladder hyperthermia using the Combat BRS device is safe and the temperature can be maintained at 43 °C. Hyperthermia therapy may increase MMC penetration into the bladder wall but does not result in an increase of MMC levels in other organs.