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Significance: For therapeutic approaches for upper tract urothelial carcinomas, the absorption μ a and reduced scattering μ s ' coefficients of these tissues are essential parameters to quantitatively evaluate the distribution of light treatment effects., Aim: The μ a and μ s ' spectra of the human ureter, fatty tissue, ureteral and renal pelvic carcinomas, and porcine ureter and fatty tissue are measured over 400 to 700 nm to evaluate projected light penetration depths δ ., Approach: The optical properties were determined with a double integrating sphere optical system and inverse Monte Carlo methods. δ was calculated and compared between normal and cancerous human tissues as well as between normal human and porcine tissues., Results: μ a and μ s ' spectra of each tissue were determined. The δ of the normal human ureter was less than those of the ureteral and renal pelvic carcinomas, whereas that of the porcine ureter was similar to that of the human ureter over 400 to 600 nm and ∼ 0.2 times smaller above 600 nm., Conclusion: Optical properties of human and porcine upper urinary tracts provide insights into light distributions and the validity of ex vivo porcine models in preclinical evaluations of laser treatments., (© 2024 The Authors.)

Radiation and bacillus Calmette-Guérin (BCG) instillations are used clinically for treatment of urothelial carcinoma, but the precise mechanisms by which they activate an immune response remain elusive. The role of the cGAS-STING pathway has been implicated in both BCG and radiation-induced immune response; however, comparison of STING pathway molecules and the immune landscape following treatment in urothelial carcinoma has not been performed. We therefore comprehensively analyzed the local immune response in the bladder tumor microenvironment following radiotherapy and BCG instillations in a well-established spontaneous murine model of urothelial carcinoma to provide insight into activation of STING-mediated immune response. Mice were exposed to the oral carcinogen, BBN, for 12 weeks prior to treatment with a single 15 Gy dose of radiation or three intravesical instillations of BCG (1 × 10 8  CFU). At sacrifice, tumors were staged by a urologic pathologist and effects of therapy on the immune microenvironment were measured using the NanoString Myeloid Innate Immunity Panel and immunohistochemistry. Clinical relevance was established by measuring immune biomarker expression of cGAS and STING on a human tissue microarray consisting of BCG-treated non-muscle-invasive urothelial carcinomas. BCG instillations in the murine model elevated STING and downstream STING-induced interferon and pro-inflammatory molecules, intratumoral M1 macrophage and T-cell accumulation, and complete tumor eradication. In contrast, radiotherapy caused no changes in STING pathway or innate immune gene expression; rather, it induced M2 macrophage accumulation and elevated FoxP3 expression characteristic of immunosuppression. In human non-muscle-invasive bladder cancer, STING protein expression was elevated at baseline in patients who responded to BCG therapy and increased further after BCG therapy. Overall, these results show that STING pathway activation plays a key role in effective BCG-induced immune response and strongly indicate that the effects of BCG on the bladder cancer immune microenvironment are more beneficial than those induced by radiation. © 2021 The Pathological Society of Great Britain and Ireland., (© 2021 The Pathological Society of Great Britain and Ireland.)

Long term-side effects from cancer therapies are a growing health care concern as life expectancy among cancer survivors increases. Damage to the bladder is common in patients treated with radiation therapy for pelvic cancers and can result in radiation (hemorrhagic) cystitis (RC). The disease progression of RC consists of an acute and chronic phase, separated by a symptom-free period. Gaining insight in tissue changes associated with these phases is necessary to develop appropriate interventions. Using a mouse preclinical model, we have previously shown that fibrosis and vascular damage are the predominant pathological features of chronic RC. The goal of this study was to determine the pathological changes during acute RC. We identified that radiation treatment results in a temporary increase in micturition frequency and decrease in void volume 4-8 weeks after irradiation. Histologically, the micturition defect is associated with thinning of the urothelium, loss of urothelial cell-cell adhesion and tight junction proteins and decrease in uroplakin III expression. By 12 weeks, the urothelium had regenerated and micturition patterns were similar to littermate controls. No inflammation or fibrosis were detected in bladder tissues after irradiation. We conclude that functional bladder defects during acute RC are driven primarily by a urothelial defect., (© 2021. The Author(s).)

Purpose: In a previous study we have shown in a mouse model that administration of nuclear factor-kappa B (NF-κB) inhibitor thalidomide has promising therapeutic effects on early radiation cystitis (ERC) and late radiation sequelae (LRS) of the urinary bladder. The aim of this study was to evaluate in the same mice the effect of thalidomide on adherens junction (AJ) proteins in ERC and LRS., Methods: Urothelial expressions of E‑cadherin and β‑catenin were assessed by immunohistochemistry in formalin-fixed paraffin-embedded (FFPE) bladder specimens over 360 days post single-dose irradiation on day 0. First, the effect of irradiation on AJ expression and then effects of thalidomide on irradiation-induced AJ alterations were assessed using three different treatment times., Results: Irradiation provoked a biphasic upregulation of E‑cadherin and β‑catenin in the early phase. After a mild decrease of E‑cadherin and a pronounced decrease of β‑catenin at the end of the early phase, both increased again in the late phase. Early administration of thalidomide (day 1-15) resulted in a steeper rise in the first days, an extended and increased expression at the end of the early phase and a higher expression of β‑catenin alone at the beginning of the late phase., Conclusion: Upregulation of AJ proteins is an attempt to compensate irradiation-induced impairment of urothelial barrier function. Early administration of thalidomide improves these compensatory mechanisms by inhibiting NF-κB signaling and its interfering effects.

The therapeutic benefit of immune checkpoint inhibitor monotherapy is limited to a subset of patients in urothelial carcinoma (UC). Previous studies showed the immunogenicity of cisplatin and irradiation. Here, we investigated whether chemoradiotherapy (CRT), a combination of cisplatin and irradiation, could improve the efficacy of postirradiation anti-programmed cell death 1 (PD-1) treatment in UC. In our advanced UC patient cohort, patients with CRT showed a significantly better objective response rate (75%/22%) and overall survival (88%/30% at 12 months) following later pembrolizumab therapy compared to those without. Then, we created syngeneic UC mouse models by inoculating MB49 cells s.c. in C57BL/6J mice to examine the potential of CRT to enhance antitumor immunity in conjunction with postirradiation anti-PD-1 treatment. Nonirradiated tumors of the mice treated with CRT/postirradiation anti-PD-1 treatment had a significantly slower growth rate and a significantly higher expression of cytotoxic T cells compared to those of the mice treated with anti-PD-1 treatment alone. The mice treated with CRT/postirradiation anti-PD-1 treatment showed the best survival. Mechanistically, CRT provoked strong direct cytotoxicity and increased expressions of immunogenic cell death markers in MB49 cells. Therefore, the combination of cisplatin and irradiation induces immunogenic cell death and potentiates postirradiation anti-PD-1 treatment efficacy in UC.

Laser technology has long been a standard treatment for many diseases. In particular, laser treatment is considered the standard of care in various urological diseases. While originally primarily restricted to stone treatment, lasers have since evolved to play an important role even in the treatment of malignant diseases. In this review, we take a closer look at the history of lasers in urology and some implications for treatments today.

Background: While radical nephroureterectomy is the treatment of choice for localized or regional urothelial carcinoma of the upper urinary tract (UTUC), the role of adjuvant radiotherapy is unclear, with conflicting data from various small studies., Patients and Methods: We sought to study the impact of adjuvant radiotherapy on UTUC by utilizing the Survelliance, Epidemiolgy, and End Results (SEER) 9 database from 1998-2011., Results: Of 2,572 identified cases, 113 patients (4.4%) received adjuvant radiotherapy, with a median age of 74 years (range=22-100 years). In univariate analysis, patients treated with adjuvant radiation therapy seemed to have a lower survival time than those without radiation therapy (19 months versus 31 months, p<0.05). However, after adjusting for covariates, including age at diagnosis, gender, race, year of diagnosis, stage, histological grade and surgery, radiation therapy did not seem to influence survival (hazard ratio=0.68; 95% confidence interval=0.68-1.06, p=0.85)., Conclusion: This hypothesis-generating, population-based analysis shows that adjuvant radiotherapy may not influence survival among patients with locoregional UTUC., (Copyright© 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.)

Objective: To determine the role of cyclooxygenase (COX) expression in the urothelium of the urinary bladder during radiation injury caused by pelvic radiotherapy for cancer therapy., Study Design: Twenty-four male Swiss Albino mice were separated into 4 groups. The first group was the control group (Group 1) and the second, third, and fourth groups were euthanized after 24 hours (Group 2), 48 hours (Group 3), and 7 days (Group 4), respectively. A single-fractioned 10 Gy of ionizing radiation was applied to all mice's pelvic zone with Co-60. Bladders were removed completely from the pelvic region. Histochemical analysis using hematoxylin and eosin and immunohistochemical analysis using anti-COX-1 and COX-2 antibodies were performed on tissue samples. The immunoreactivities of the urinary bladder were quantified using H-score measurement, and statistical comparison was performed., Results: In the immunohistochemical examination the COX-1 immunoreactivities were found to be higher in the urothelium of the bladder in the radiation exposed groups than in the normal control group (group 1) (p < 0.005). Additionally, high immunoreactivity of COX-2 molecule was established in groups 2, 3, and 4 of radiation groups as compared to group 1 (p < 0.005) in examination of the urothelium. COX-1 and COX-2 immunoreactivities in the submucosa were detected higher in group 4 than in the other groups (p < 0.005)., Conclusion: COX-1 and COX-2 expressions in the urothelium and subepithelium of the urinary bladder were investigated in mice during the acute radiation response. The expression of COX-1 and COX-2 in the urothelium seems to prevent bladder damage from radiation, supplying differentiation and restoration of the urothelium.

Urothelial defects may manifest as various types of signs of symptoms such as frequency and urgency, haematuria and pain. Both prevention and treatment of urothelial damage is fundamental. Many currently adopted treatments lack robust clinical data and are associated with variability in management strategies. Glycosoaminoglycan (GAG) therapy is one of the most promising therapies in treatment of chemotherapy and radiotherapy-induced urothelium defects, and has been investigated in both animal models and clinical studies.

The management of patients with cystitis-related symptoms due to urinary tract infection, bladder pain syndrome (BPS) or radio/chemo-induced cystitis remains challenging. A component in the pathophysiology of these symptoms relates to the fact that the urothelium is a highly metabolically active structure and that alterations in this structure can give rise to a variety of symptoms.

Purpose: We primarily determined whether the small animal radiation research platform could create a rat radiation cystitis model via targeted bladder irradiation (phase I). The response to treating early phase radiation cystitis in rats with transurethral catheter instillation of liposomal tacrolimus was also examined (phase II)., Materials and Methods: In phase I 16 adult female Sprague Dawley® rats were used. Metabolic urination patterns were analyzed before and after exposure to 20, 30 or 40 Gy radiation. In phase II irradiated rats were randomly assigned to receive a single instillation of saline or liposomal tacrolimus., Results: The 40 Gy radiation dose induced statistically significant reductions in the intermicturition interval compared to the lower radiation doses. By approximately 20 minutes 40 Gy radiation caused a significant decrease in the mean intermicturition interval (p < 0.0001). Histological analysis revealed degenerative epithelial changes and urothelial swelling with evidence of pseudocarcinomatous epithelial hyperplasia. Therefore, 40 Gy were chosen for the phase II efficacy study. There was no measurable change in total voided urine volume after irradiation, or after liposomal tacrolimus or saline instillation. Liposomal tacrolimus significantly increased the post-irradiation intermicturition interval by approximately 30 minutes back to baseline (p < 0.001)., Conclusions: The radiation cystitis rat model showed a dose dependent decrease in the intermicturition interval without inducing short-term skin or gastrointestinal damage. This study demonstrates that liposomal tacrolimus may be a promising new intravesical therapy for the rare, serious condition of radiation cystitis., (Copyright © 2015 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.)

The differentiation of urothelial cells results in normal terminally differentiated cells or by alternative pathways in low-grade or high-grade urothelial carcinomas. Treatments with traditional surgical and chemotherapeutical approaches are still inadequate and expensive, as bladder tumours are generally highly recurrent. In such situations, alternative approaches, using irradiation of the cells and nanoparticles, are promising. The ways in which urothelial cells, at different differentiation levels, respond to UV-irradiation (photolytic treatment) or to the combination of UV-irradiation and nanoparticles (photocatalytic treatment), are unknown. Here we tested cytotoxicity of UV-irradiation on (i) normal porcine urothelial cells (NPU), (ii) human low-grade urothelial cancer cells (RT4), and (iii) human high-grade urothelial cancer cells (T24). The results have shown that 1 minute of UV-irradiation is enough to kill 90% of the cells in NPU and RT4 cultures, as determined by the live/dead viability assay. On the other hand, the majority of T24 cells survived 1 minute of UV-irradiation. Moreover, even a prolonged UV-irradiation for 30 minutes killed <50% of T24 cells. When T24 cells were pre-supplemented with mesoporous TiO2 microbeads and then UV-irradiated, the viability of these high-grade urothelial cancer cells was reduced to <10%, which points to the highly efficient cytotoxic effects of TiO2 photocatalysis. Using electron microscopy, we confirmed that the mesoporous TiO2 microbeads were internalized into T24 cells, and that the cell's ultrastructure was heavily compromised after UV-irradiation. In conclusion, our results show major differences in the sensitivity to UV-irradiation among the urothelial cells with respect to cell differentiation. To achieve an increased cytotoxicity of urothelial cancer cells, the photocatalytic approach is recommended.

Introduction: The incidence, treatment, and outcome of urethral recurrence (UR) after radical cystectomy (RC) for muscle-invasive bladder cancer with orthotopic neobladder in women have rarely been addressed in the literature., Patients and Methods: A total of 12 patients (median age at recurrence: 60 years) who experienced UR after RC with an orthotopic neobladder were selected for this study from a cohort of 456 women from participating institutions. The primary clinical and pathological characteristics at RC, including the manifestation of the UR and its treatment and outcome, were reviewed., Results: The primary bladder tumors in the 12 patients were urothelial carcinoma in 8 patients, squamous cell carcinoma and adenocarcinoma in 1 patient each, and mixed histology in 2 patients. Three patients (25%) had lymph node-positive disease at RC. The median time from RC to the detection of UR was 8 months (range 4-55). Eight recurrences manifested with clinical symptoms and 4 were detected during follow-up or during a diagnostic work-up for clinical symptoms caused by distant metastases. Treatment modalities were surgery, chemotherapy, radiotherapy, and bacillus Calmette-Guérin urethral instillations. Nine patients died of cancer. The median survival after the diagnosis of UR was 6 months., Conclusions: UR after RC with an orthotopic neobladder in females is rare. Solitary, noninvasive recurrences have a favorable prognosis when detected early. Invasive recurrences are often associated with local and distant metastases and have a poor prognosis., (© 2014 S. Karger AG, Basel.)

We review the morphology and differential diagnoses of pseudocarcinomatous hyperplasia of the bladder, using a study case to illustrate the discussion. Pseudocarcinomatous hyperplasia is a rare, reactive response to an ischemic insult, classically to radiation therapy, and consists of proliferative, pseudoinfiltrative urothelial nests within the stroma. The presence of background radiation therapy-related changes, such as numerous dilated thrombosed vessels, reactive-appearing endothelial and stromal cells, edema, and hemorrhage, can provide clues to the diagnosis. The main differential diagnoses include invasive urothelial carcinoma and the nested variant of urothelial carcinoma; morphologic features, such as the presence or absence of background therapy-related changes and the architecture and the cytologic atypia of the nests, can help distinguish between pseudocarcinomatous hyperplasia and urothelial carcinoma.

Purpose: Technological developments provide a lot of conveniences to our lives. This issue is one of the risks that arise along with these conveniences. In our study we tried to understand the impact of electromagnetic waves from mobile phones on bladder tissue., Materials and Methods: Twenty-one adult male albino rats were divided into three equal groups. Group 1 was exposed to electromagnetic wave for 8 hours per day for 20 days and then their bladders were taken off immediately. Group 2 was firstly exposed to electromagnetic wave for 8 hours per day for 20 days then secondly another for 20 days without exposition to electromagnetic wave and then their bladders were taken off. Group 3 was the control group and they were not exposed to electromagnetic wave., Results: Under microscopic examination of bladder tissue, in the first group severe inflammatory cell infiltration was seen in lamina propria and muscle layer in contrast to intact urothelium. In the second group mild inflammatory cell infiltration was seen in lamina propria and muscle layer. The mean scores for the three groups were 5.5 ± 2.5, 0.8 ± 1.3 and 1.2 ± 1.5 respectively. Mean score of group 1 was statistically higher than others (p = 0.001)., Conclusion: Intensive use of mobile phones has negative impact on bladder tissue as well as the other organs. Keeping a minimum level of mobile phone use makes it easy to be kept under control of diseases in which inflammation is an etiologic factor.

Irradiation of rats with γ-quanta at relatively low doses induces a sustainable dose-independent increase in the occurrence of lethal cytoplasmic disorders in the renal tubules epithelium together with sustainable and as well dose-independent subcelluar compensation and restorative processes. Over the period of research (6 months) these processes led to no population recovery. The detected alterations are referred to the category of non-targeted non-mutagenic effects and they are of interest because they address the issue of the sensitivity of low renewable tissues to radiation.

Introduction: Advanced urothelial carcinoma is associated with a poor prognosis. In the metastatic setting, the response rate to first-line, cisplatin-containing chemotherapy is high, but survival is poor. Second-line treatment options are limited. Advanced age at diagnosis and the presence of comorbidities often preclude treatment with cisplatin-containing regimens., Areas Covered: This review addresses the current therapy of urothelial carcinoma, the unmet needs in treatment and the status of drug development in this disease. The molecular targets identified and efforts to incorporate targeted agents into therapy will be addressed., Expert Opinion: There have been no major advances in the treatment of urothelial carcinoma in three decades. Despite high response rates in the first-line setting, survival is limited. Major impediments to improved outcomes include poor durability of response to first-line chemotherapy and lack of second-line treatments. Better understanding in tumor biology has identified multiple targets in urothelial carcinoma; however, such discoveries have yet to lead to the incorporation of targeted agents into the routine treatment of urothelial carcinoma. Multiple ongoing clinical trials are investigating the use of targeted agents in urothelial carcinoma. Continued efforts are underway to better understand the molecular drivers of disease and such efforts are likely to identify additional therapeutic targets.

Human DNA polymerase iota (pol ι) possesses high error-prone DNA replication features and performs translesion DNA synthesis. It may be specialized and strictly regulated in normal mammalian cells. Dysregulation of pol ι may contribute to the acquisition of a mutator phenotype. However, there are few reports describing the transcription regulatory mechanism of pol ι, and there is controversy regarding its role in carcinogenesis. In this study, we performed the deletion and point-mutation experiment, EMSA, ChIP, RNA interference and western blot assay to prove that c-Jun activated by c-Jun N-terminal kinase (JNK) regulates the transcription of pol ι in normal and cancer cells. Xeroderma pigmentosum group C protein (XPC) and ataxia-telangiectasia mutated related protein (ATR) promote early JNK activation in response to DNA damage and consequently enhance the expression of pol ι, indicating that the novel role of JNK signal pathway is involved in DNA damage response. Furthermore, associated with elevated c-Jun activity, the overexpression of pol ι is positively correlated with the clinical tumor grade in 97 bladder cancer samples and may contribute to the hypermutagenesis. The overexpressed pol ι-involved mutagenesis is dependent on JNK/c-Jun pathway in bladder cancer cells identifying by the special mutation spectra. Our results support the conclusion that dysregulation of pol ι by JNK/c-Jun is involved in carcinogenesis and offer a novel understanding of the role of pol ι or c-Jun in mutagenesis.

Radiotherapy is often used to treat prostate tumors, but the normal bladder is usually adversely affected. Using an animal model of pelvic radiation, we investigated whether glutamine nutritional supplementation can prevent radiation-induced damage to the bladder, especially in its more superficial layers. Male rats aged 3-4 months were divided into groups of 8 animals each: controls, which consisted intact animals; radiated-only rats, which were sacrificed 7 (R7) or 15 (R15) days after a radiation session (10Gy aimed at the pelvico-abdominal region); and radiated rats receiving l-glutamine supplementation (0.65g/kg body weight/day), which were sacrificed 7 (RG7) or 15 (RG15) days after the radiation session. Cells and blood vessels in the vesical lamina propria, as well as the urothelium, were then measured using histological methods. The effects of radiation were evaluated by comparing controls vs. either R7 or R15, while a protective effect of glutamine was assessed by comparing R7 vs. RG7 and R15 vs. RG15. The results showed that, in R7, epithelial thickness, epithelial cell density, and cell density in the lamina propria were not significantly affected. However, density of blood vessels in R7 was reduced by 48% (p<0.05) and this alteration was mostly prevented by glutamine (p<0.02). In R15, density of blood vessels in the lamina propria was not significantly modified. However, epithelial thickness was reduced by 25% (p<0.05) in R15, and this effect was prevented by glutamine (p<0.01). In R15, epithelial cell density was increased by 35% (p<0.02), but glutamine did not protect against this radiation-induced increase. Cell density in the lamina propria was likewise unaffected in R15. Density of mast cells in the lamina propria was markedly reduced in R7 and R15. The density was still reduced in RG7, but a higher density in RG15 suggested a glutamine-mediated recovery. Alpha-actin positive cells in the lamina propria formed a suburothelial layer and were identified as myofibroblasts. Thickness of this layer was increased in R7, but was similar to controls in RG7, while changes in R15 and RG15 were less evident. In conclusion, pelvic radiation leads to significant acute and post-acute alterations in the composition and structural features of the vesical lamina propria and epithelium. Most of these changes, however, can be prevented by glutamine nutritional supplementation. These results emphasize, therefore, the potential use of this aminoacid as a radioprotective drug., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Curative radiotherapy, with or without concurrent chemotherapy, is recognized as a standard treatment option for muscle-invasive bladder cancer. It is commonly used for two distinct groups of patients: either for those medically unfit for surgery, or as part of a 'bladder preserving' management plan incorporating the possibility of salvage cystectomy. However, in both situations, the approach to radiotherapy varies widely around the world. The Australian and New Zealand Faculty of Radiation Oncology Genito-Urinary Group recognised a need to develop consistent, evidence-based guidelines for patient selection and radiotherapy technique in the delivery of curative radiotherapy. Following a workshop convened in May 2009, a working party collated opinions and conducted a wide literature appraisal linking each recommendation with the best available evidence. This process was subject to ongoing re-presentation to the Faculty of Radiation Oncology Genito-Urinary Group members prior to final endorsement. These Guidelines include patient selection, radiation target delineation, dose and fractionation schedules, normal tissue constraints and investigational techniques. Particular emphasis is given to the rationale for the target volumes described. These Guidelines provide a consensus-based framework for the delivery of curative radiotherapy for muscle-invasive bladder cancer. Widespread input from radiation oncologists treating bladder cancer ensures that these techniques are feasible in practice. We recommend these Guidelines be adopted widely in order to encourage a uniformly high standard of radiotherapy in this setting, and to allow for better comparison of outcomes., (© 2012 The Authors. Journal of Medical Imaging and Radiation Oncology © 2012 The Royal Australian and New Zealand College of Radiologists.)

The therapy for non-bacterial cysitides is often based on purely symptom-oriented measures which in many cases relieve the patient's symptoms but cannot stop the chronic progression of the disease. The present article summarises the most common forms of non-bacterial cystitis (interstitial, radiogenic, chemotherapy-induced) with their common pathophysiology and then introduces the most common therapeutic procedures. With regard to radiogenic and chemotherapy-induced cystitis it must be considered that optimal preventative measures can often markedly delay or even prevent the development of the inflammatory processes. The preventative therapeutic measures mentioned in this article should thus constitute a fixed part of the accompanying therapy within the framework of tumour-related treatment. As alternatives or supplements to symptomatic therapy, causal therapy options show good response rates. Besides successful hyperbaric oxygen therapy, this also holds for hyalurane that is instilled with the aim of repairing the damaged glycosamine layer in the endothelium of the urinary bladder and so opens new curative options in cases that were previously considered as therapy resistant. A prior potassium-sensitivity test is recommended as this allows the putative success of the therapy to be predicted with a high probability. However. It is equally important, especially in cases of interstitial cystitis, that the diagnosis is made as early as possible which was often not done in the past., (© Georg Thieme Verlag KG Stuttgart ˙ New York.)

This study was designed to determine changes in cell numbers, proliferation (using Ki-67) and EGFR expression in mouse bladder urothelium during the early and late radiation response. Groups of mice were irradiated with a single dose of 20 Gy and assayed 0-360 days later. Urothelial cells were counted. After immunohistochemistry, the absolute and relative numbers of Ki-67(+) and EGFR(+) cells were analyzed. Radiation exposure resulted in a decrease in total urothelial cell numbers to 49% by day 31, with restoration of cellularity by day 180. In contrast, at day 360, an increase in total cell number (143%) was seen. Slightly increased Ki-67 expression was found at days 120 and 180 after treatment, followed by a pronounced elevation at days 240 and 360. Compared to controls, higher EGFR expression was detected up to day 360 after irradiation. A positive correlation was found between total urothelial cells numbers and Ki-67 as well as EGFR expression. Radiation exposure results in an increased urothelial expression of EGFR that precedes urothelial restoration, indicating a contribution of the EGF/EGFR system to urothelial proliferation and differentiation. Further studies are needed to evaluate the impact of EGFR inhibition on radiation effects in the urinary bladder.

Urinary bladder urothelium as well as cells in the microenvironment of lamina propria (endothelial elements, fibroblasts and lymphocytes) demonstrate a number of responses to chronic persistent long-term, low-dose ionizing radiation (IR). Thus, oxidative stress occurs, accompanied by up-regulation of at least two signaling pathways (p38 mitogen-activated protein kinase and nuclear factor-kappaB cascades) and activation of growth factor receptors, in the bladder urothelium of people living in Cesium 137-contaminated areas of Ukraine, resulting in chronic inflammation and the development of proliferative atypical cystitis, so-called Chernobyl cystitis, which is considered a possible pre-neoplastic condition in humans. Furthermore, significant alterations in regulation of cell cycle transitions are associated with increased cell proliferation, along with up-regulated ubiquitination and sumoylation processes as well as inefficient DNA repair (base and nucleotide excision repair pathways) in the affected urothelium. The microenvironmental changes induced by chronic long-term, low-dose IR also appear to promote angiogenesis and remodeling of the extracellular matrix that could facilitate invasion as well as progression of pre-existing initiated cells to malignancy. Based on the available findings, new strategies have been developed for predicting and treatment of Chernobyl cystitis-a first step in urinary bladder carcinogenesis in humans.

Background and Objectives: Photodynamic therapy (PDT) of superficial bladder cancer may cause damages to the normal surrounding bladder wall. Prevention of these is important for bladder healing. We studied the influence of photosensitizer concentration, irradiation parameters, and production of reactive oxygen species (ROS) on the photodynamically induced damage in the porcine urothelium invitro. The aim was to determine the threshold conditions for the cell survival., Methods: Living porcine bladder mucosae were incubated with solution of hexylester of 5-aminolevulinic acid (HAL). The mucosae were irradiated with increasing doses and cell alterations were evaluated by scanning electron microscopy and by Sytox green fluorescence. The urothelial survival score was correlated with Protoporphyrin IX (PpIX) photobleaching and intracellular fluorescence of Rhodamine 123 reflecting the ROS production., Results: The mortality ratio was dependent on PpIX concentration. After 3 hours of incubation, the threshold radiant exposures for blue light were 0.15 and 0.75 J/cm(2) (irradiance 30 and 75 mW/cm(2), respectively) and for white light 0.55 J/cm(2) (irradiance 30 mW/cm(2)). Photobleaching rate increased with decreasing irradiance. Interestingly, the DHR123/R123 reporter system correlated well with the threshold exposures under all conditions used., Conclusions: We have determined radiant exposures sparing half of normal urothelial cells. We propose that the use of low irradiance combined with systems reporting the ROS production in the irradiated tissue could improve the in vivo dosimetry and optimize the PDT., ((c) 2006 Wiley-Liss, Inc.)

Background: Nuclear texture analysis measures phenotypic changes in chromatin distribution within a cell nucleus, while the alkaline Comet assay is a sensitive method for measuring the extent of DNA breakage in individual cells. The authors aim to use both methods to provide information about the sensitivity of cells to ionizing radiation., Methods: The alkaline Comet assay was performed on six human bladder carcinoma cell lines and one human urothelial cell line exposed to gamma-radiation doses from 0 to 10 Gy. Nuclear chromatin texture analysis of 40 features was then performed in the same cell lines exposed to 0, 2, and 6 Gy to explore if nuclear phenotype was related to radiation sensitivity., Results: Comet assay results demonstrated that the cell lines exhibited different levels of radiosensitivity and could be divided into a radiosensitive and a radioresistant group at >6 Gy. Using stepwise discriminant analysis, a subset of important nuclear texture features that best discriminated between sensitive and resistant cell lines were identified A classification function, defined using these features, correctly classified 81.75% of all cells into their radiosensitive or radioresistant groups based on their pretreatment chromatin phenotype. Posttreatment chromatin changes also varied between cell lines, with sensitive cell lines showing a relaxed chromatin conformation following radiation, whereas resistant cell lines exhibited chromatin condensation., Conclusions: The authors conclude that the alkaline Comet assay and nuclear texture methodologies may prove to be valuable aids in predicting the response of tumor cells to radiotherapy.

Purpose: To determine changes of the urothelial barrier during the early as well as late radiation response in mouse urinary bladder., Materials and Methods: Groups of mice were irradiated with a single dose of 20Gy and sacrificed between days 0 and 360. Urothelial cell numbers were counted, and the fraction of urothelium with a positive immunohistochemical signal for uroplakin-III (UP-III) on the luminal surface of the bladder was defined. Also, cytoplasmic UP-III staining signal in urothelium was quantified using an arbitrary score (0-3)., Results: Irradiation resulted in a significant decrease in the number of superficial umbrella cells during the early response phase (days 0-31) as well as during the initial late radiation reaction (days 90, 120). Progressive loss of the UP-III layer on the bladder luminal surface correlated with the decrease in the number of umbrella cells (p=0.002). Also, increased cytoplasmic staining of UP-III in the urothelium was seen after irradiation, correlating negatively with the reduction of the superficial UP-III layer (p<0.0001)., Conclusion: Irradiation of the urinary bladder results in morphological impairment of the urothelial barrier that is associated with a loss of superficial umbrella cells during the early as well as initial late radiation response phase.

A ureter primary explant technique, using porcine tissue sections was developed to study bystander effects under in vivo like conditions where dividing and differentiated cells are present. Targeted irradiations of ureter tissue fragments were performed with the Gray Cancer Institute charged particle microbeam at a single location (2 microm precision) with 10 3He2+ particles (5 MeV; LET 70 keV/microm). After irradiation the ureter tissue section was incubated for 7 days allowing explant outgrowth to be formed. Differentiation was estimated using antibodies to Uroplakin III, a specific marker of terminal urothelial differentiation. Even although only a single region of the tissue section was targeted, thousands of additional cells were found to undergo bystander-induced differentiation in the explant outgrowth. This resulted in an overall increase in the fraction of differentiated cells from 63.5+/-5.4% to 76.6+/-5.6%. These changes are much greater than that observed for the induction of damage in this model. One interpretation of these results is that in the tissue environment, differentiation is a much more significant response to targeted irradiation and potentially a protective mechanism.

The work is devoted to studying a possibility to use, for cytological diagnostics of urogenital neoplasms, of macrosystemic approaches, aimed to estimate cell systemic reactions during blasttransformation and treatment (exemplified by 95 urinary bladder cancer patients). Changes in size of nuclear and cytoplasmic areas were studied, in addition to the average activity of synthetic processes or functional activity of cell structures, and to the level of heterogeneity of functional tension in the cell space.

Topical and systemic therapeutic agents and treatment modalities, such as thiotepa and mitomycin C, cyclophosphamide, bacillus Calmette-Guerin, radiation therapy, photodynamic and laser therapy, and gene therapy, produce a host of changes in the bladder, some of them mimicking cancer. Pathologists must be aware that following these types of treatment, the clinical utility of urinary cytology is reduced.

Today, in vitro culturing of autologous cells is an established method in the field of tissue reconstruction. It can be applied to urothelial cells and could have many clinical implications in urological reconstructive surgery. This development calls for quality controls concerning cells used for clinical treatment when cells are autotransplanted back to the patient. We have studied cultured cells in order to detect whether genetic or morphologic changes occur. Urothelial cells isolated from bladder lavage were cultured according to different protocols based on the presence or absence of feeder cells. Genetic studies were performed by means of karyotyping with standard G-banding and interphase fluorescent in situ hybridization (FISH) analyses. The morphology of these epithelial cells was judged as well as immunostaining for epithelial cell markers. In addition, to minimize the risk of feeder cell contamination, proliferation studies were performed on cultures including feeder cells that had been pretreated with different doses of mitomycin or radiation. In initial studies, when using feeder cells in each passage according to standard protocols, urothelial cells proliferated unfavourably after the fourth passage with increasing numbers of mouse cells as well as urothelial tetraploid cells. We could also show that urothelial cells from bladder lavage need feeder cells in order to establish primary cultures. Further propagation up to 14 passages was performed without feeder cells and the urothelial cells retained normal karyotypes. We also found that mitomycin treatment had its main effect on feeder cells during the first 2 h. When feeder cells were irradiated, 20 Gy was effective and no feeder cell contamination was seen. In conclusion, we found that a high standard of quality in urothelial cell culturing can be achieved with a careful culturing technique., (Copyright (c) 2005 S. Karger AG, Basel.)

Radiation adaptive response in terms of induced radioresistance or hyperradiosensitivity, has been studied in HCV29 (human bladder epithelium) and RT4 (human bladder carcinoma) cell lines. After pre-irradiation doses of 0.05 Gy or 0.1 Gy, HCV29 cells showed induced radioresistance, whereas after pre-irradiation doses of 0.05 Gy, 0.1 Gy, 0.2 Gy, and 0.5 Gy, the RT4 cells clearly showed hyperradiosensitivity. On the basis of these results, an approach has been developed that may lead to a concept for a new radiotherapeutic regimen of bladder cancer that includes protection of normal cells, on the one hand, and the potential of tumor cell damage, on the other hand. These findings need to be confirmed in further studies for the benefit of the patients.

The existence of mitochondrial nitric oxide (NO) synthase (mtNOS) has been controversial since it was first reported in 1995. We have addressed this issue by making direct microsensor measurements of NO production in the mitochondria isolated from mouse hearts. Mitochondrial NO production was stimulated by Ca2+ and inhibited by blocking electrogenic Ca2+ uptake or by using NOS antagonists. Cardiac mtNOS was identified as the neuronal isoform by the absence of NO production in the mitochondria of mice lacking the neuronal but not the endothelial or inducible isoforms. In cardiomyocytes from dystrophin-deficient (mdx) mice, elevated intracellular Ca2+, increased mitochondrial NO production, slower oxidative phosphorylation, and decreased ATP production were detected. Inhibition of mtNOS increased contractility in mdx but not in wild-type cardiomyocytes, indicating that mtNOS may protect the cells from overcontracting. mtNOS was also implicated in radiation-induced cell damage. In irradiated rat/mouse urinary bladders, we have evidence that mitochondrially produced NO damages the urothelial "umbrella" cells that line the bladder lumen. This damage disrupts the permeability barrier thereby creating the potential to develop radiation cystitis. RT-PCR and Southern blot analyses indicate that mtNOS is restricted to the umbrella cells, which scanning electron micrographs show are selectively damaged by radiation. Simultaneous microsensor measurements demonstrate that radiation increases NO and peroxynitrite (ONOO-) production in these cells, which can be prevented by transfection with manganese superoxide dismutase (MnSOD) or instillation of NOS antagonists during irradiation or irradiation of bladders devoid of mtNOS. These studies demonstrate that mtNOS is in the cardiomyocytes and urothelial cells, that it is derived from the neuronal isoform, and that it can be either protective or detrimental.

Purpose: To assess the effect of single-dose irradiation on intercellular adhesion molecule 1 (ICAM-1) expression in the urothelium of mouse urinary bladder and to correlate ICAM-1 variations with fluctuations in storage capacity during the early and late radiation response., Materials and Methods: Groups of female C3H mice were subjected to irradiation with either 20 or 0 Gy. The intensity of immunohistochemical ICAM-1 staining in the urothelium was assessed in a semiquantitative way applying an arbitrary score (0-5). Changes in bladder storage function were assessed by transurethral cystometry., Results: For the early radiation response phase, a reduction in bladder capacity by >50%, i.e. a positive functional radiation response, was seen in 40% of the irradiated animals between days 0 and 15, and in 64% of animals during days 16-30. During the late response phase, 71% of the animals sacrificed after day 180 developed a positive functional response. Urothelial cells were found to express ICAM-1 constitutively. Irradiation resulted in an early rise in staining signal by day 2, with a maximum on day 4 and a return to control values on day 13. A permanent increase in ICAM-1 staining signal was observed in the late phase, from day 90 to 360 after irradiation. The expression of ICAM-1 in animals with a positive late response was 4.2+/-1.2 (mean+/-standard deviation), compared with 2.6+/-1.0 in non-responders (p=0.0009)., Conclusion: Irradiation induces significant acute and chronic changes in urothelial ICAM-1 expression indicating that the urothelium contributes to the pathogenesis of both acute and late radiation effects in the urinary bladder.

Purpose: We determined whether base and nucleotide excision repair is activated in bladder urothelium by chronic persistent low doses of ionizing radiation in male patients with benign prostate hyperplasia and females with chronic cystitis living more than 15 years in Cs contaminated areas after the Chernobyl accident in Ukraine., Materials and Methods: Bladder urothelial biopsies from 204 patients were subjected to histological examination and biopsies from 35 were subjected to immunohistochemical study of 8-hydroxy-2'deoxyguanosine, 8-oxoguanine-DNA-glycosylase, apurinic/apyrimidinic endonuclease and xeroderma pigmentosum A endonuclease., Results: Chronic proliferative atypical cystitis with multiple foci of dysplasia and carcinoma in situ were observed in 139 (89%) and in 91 (58%) of 156 group 1 patients from radio contaminated areas, respectively, as well as 10 small transitional cell carcinomas. Chronic cystitis with areas of dysplasia was detected in 9 of 48 patients (19%) in control group 2 from clean (without radio contamination) areas of Ukraine. Greatly elevated levels of 8-hydroxy-2'deoxyguanosine, 8-oxoguanine-DNA-glycosylase, apurinic/apyrimidinic endonuclease and xeroderma pigmentosum A were evident in the urothelium in group 1, accompanied by increased Cs in the urine., Conclusions: These findings support the hypothesis that significant activation of DNA damage repair (base and nucleotide excision repair) is induced by the oxidative stress generated by long-term low doses of ionizing radiation. The levels of DNA oxidative adducts pointing to mutagenic and carcinogenic potential were in line with the histopathologically diagnosed urothelial lesions.

The ureter primary explant technique was developed to study bystander effects under in vivo like conditions where stem and differentiated cells are present. Irradiation was performed with a 3He2+ charged particle microbeam available at the Gray Cancer Institute, with high (approximately 2 microns) precision. Tissue sections from porcine ureters were pre-irradiated with the microbeam at a single location with 10 3He2+ particles (5 MeV; LET 70 keV.micron-1). After irradiation, the tissue section was incubated for 7 days, thus allowing the explant outgrowth to form. Total cellular damage (total fraction of micronucleated and apoptotic cells) was measured according to morphological criteria. Apoptosis was also assessed using a 3'-OH DNA end-labelling technique. Premature differentiation was estimated using antibodies to uroplakin III, a specific marker of terminal urothelial differentiation. Results of our experiments demonstrated a significant bystander-induced differentiation and a less significant increase in apoptotic and micronucleated cells. A hypothesis based on the protective nature of the bystander effect is proposed.

The existence of a bystander effect following both alpha and gamma irradiation of many cell lines is not now in dispute. The significance of this effect for cancer risk assessment and radiotherapy treatment planning requires demonstration of its relevance in vivo. The problem in demonstrating the existence of the effect in vivo is that other systemic effects may mask or confound the effect being investigated and it is practically impossible to attribute an effect in a particular cell to a signal produced in another irradiated cell. To approach this problem, we have developed an assay where fragments of human tissue can be irradiated ex vivo and the media harvested and added to unirradiated, allogenic explants or to a clonogenic cell line which has a well characterized and stable response to the bystander signal. The variation in production of the signal from patient to patient can thus be assessed using molecular and cellular endpoints. A study using tissue from over 100 patients and from mouse strains with well characterized responses to low level radiation exposure shows that there is variation in the effect of the signal produced by irradiated tissue from different patients. Gender, smoking status and the existence of a bladder malignancy influence the expression of the signal by normal urothelium. The effects of exposure to medium containing the signal are transmitted to distant progeny of the exposed cell population. The results may be important not only for understanding radiation risk mechanisms for protection but also for radiotherapy treatment planning where they may open new avenues for development of drugs for combined therapy.

Loss of p53 function is a feature of many types of malignancy, including transitional-cell carcinoma (TCC), where it is associated with high-grade lesions and the development of muscle-invasive disease. Genotoxic agents used as part of the treatment strategy may contribute to tumour progression by inducing further non-lethal DNA damage in surviving cells. To determine the role of p53 in cellular responses to genotoxic agents, we used cultured normal human urothelial (NHU) cells and NHU cells with disabled p53 function. Mitomycin C and gamma-radiation caused normal cells to undergo an extended period of cell-cycle arrest, followed by complete recovery of proliferative potential. In contrast, cells with disabled p53 function, whether karyotypically normal (HU-E6 cells) or post-crisis with karyotypic abnormalities (HU-E6P cells), underwent extensive apoptosis. Overall survival was dose-dependent, and surviving HU-E6 cells from low-dose treatments showed clonal karyotypic abnormalities. These findings demonstrate that p53 status is a crucial factor in determining the ability of urothelial cells to survive DNA damage and suggest caution in the use of genotoxic treatments for low-grade tumours as our data imply that malignancies that have not yet lost p53 function will show the same "repair-and-recovery" response as normal cells., (Copyright 2001 Wiley-Liss, Inc.)

Pattern and cellular changes attributable to neoadjuvant hormonal therapy (NHT) might cause the unwary pathologist to overgrade or fail to recognize a treated prostatic cancer. Overdiagnosis and overgrading of surgical resections and biopsies can be avoided if an appropriate history of therapy is conveyed with the surgical specimen and if the pathologist is aware of the altered morphology of prostatic cancer treated by NHT alone or NHT plus radiation. Study of three prostatectomy specimens with post-NHT predominance of neuroendocrine cells showed positive staining for prostate specific antigen (PSA) and prostatic acid phosphatase (PAP), as well as staining for chromogranin and synaptophysin in Paneth-like and small neuroendocrine cells. Difficult-to-interpret needle biopsies and transurethral resection (TUR) biopsies of prostate, where the urologic pathologist's suspicion of a radiation effect was confirmed by additional history, showed absence of the basal cell layer with 34 beta E12 keratin immunostaining in prostatic cancer glands, while basal cells were present in the nonneoplastic glands with radiation-induced atypia. Postradiation salvage prostatectomy specimens showed greater apoptosis after combined NHT and radiation than after radiation without NHT. Changes attributable to radiation and radiation plus NHT are illustrated.

In an attempt to assess genetic variation underlying the variation in human responses to radiation exposure, measurements of apoptosis, necrosis and induction of key proteins were made in primary explant cultures of human normal urothelium and correlated with growth post- exposure to a range of doses of (60)Co. These data were validated by similar experiments using CBA/H and C57/BL6 mouse strains, known to exhibit genetically determined differences in response to radiation. The data for human tissues show a wide variation in response with three broad categories being identifiable. The commonest had a hypersensitive response involving considerable apoptosis in the low dose region, followed by 'induction' of a survival response at higher doses involving the persistence of abnormal cells. The pattern of gene expression was consistent with suppression of apoptosis. The second category showed no induction of survival and considerable necrosis was seen in the progeny. The rarest category showed an extremely hypersensitive low dose response and despite induction of a survival response, the sensitivity to higher doses was very severe. Considerable apoptosis and necrosis were seen in these cultures. In the mouse experiments, strain CBA/H (mice known to exhibit genetic instability post-irradiation) had lower levels of delayed cell death and apoptosis than C57/BL6 mice (which exhibit significantly less instability). It is concluded that there is a variation in response to radiation between human patient cultures which is detectable in this system and which is consistent with a pattern of radiation- induced delayed death/apoptosis correlating with long-term genomic stability. The mouse experiments demonstrate the importance of genetic factors in determining these responses.

Purpose: The present review summarizes experimental studies of the pathogenesis of acute radiation-induced changes in urinary bladder function., Material and Methods: Transurethral cystometry was used for longitudinal assessment of bladder function in mice. With this technique, radiation-induced changes in storage capacity can be quantified. In histological studies, changes in urothelial cell density and in urothelial protein expression during the acute radiation response were determined. Acetylsalicylic acid (ASA) was used for the treatment of acute functional changes., Results: The histological studies did not reveal any systematic fluctuations in urothelial cell density during the time of the acute radiation response. However, characteristic changes in the expression of proteins associated with urothelial cell function, differentiation and cell contact were observed, which correlated with the functional impairment. By local or systematical application of ASA, a significant restoration of bladder function compared to placebo treatment could be achieved., Conclusion: Acute functional radiation effects in the urinary bladder are not based on urothelial denudation. However, changes in protein expression indicate an impairment of the urothelial barrier function. The results of ASA treatment demonstrate that prostaglandins are involved in the response. Alterations in urothelial or endothelial prostaglandin metabolism may be primarily radiation-induced or secondary because of the impaired urothelial barrier.

We have previously shown that primary explant cultures of human urothelium exposed to low doses of gamma-radiation subsequently accumulate a high level of stable p53 but it was not clear from those studies whether this protein stabilization occurred through an event in another gene involved in p53 protein control or possibly an epigenetic event. In these experiments, primary urothelial cultures from five different patients were exposed to either 0.5 or 5 Gy gamma-radiation from a 60 Cobalt source and allowed to grow for 7-10 division cycles to allow development of any radiation-induced, non-lethal changes in the cells. C-myc, Bcl-2 and stable p53 proteins were found to be elevated in cultures following both radiation doses. PCR-SSCPE analysis of the p53 gene was performed on cultures in order to determine whether genetic mutations could be the underlying basis for persistent increased stable p53 expression. Following 0.5 Gy exposure, the cultures also developed multiple distinct 'foci' of rapidly dividing cells which strongly overexpressed p53. These grew on a background of morphologically normal cells. When such foci were selectively analysed for their p53 mutation status by PCR-SSCPE, there was evidence that they contained cells which had developed changes to the p53 gene post-irradiation. These changes appeared to occur more frequently in focal cells than in cells of normal morphological appearance in the same culture. These results may have mechanistic importance given the controversy regarding low-dose radiation effects and p53-related genomic instability.

Explant cultures of normal human uroepithelium were established, exposed to a range of 60Co gamma-ray doses from 0.1-5 Gy and grown for 14 days. Expression of Myc, p53 and Bc12 proteins in the epithelial cells which grew from irradiated explants was measured in situ using immunocytochemistry. The results show that overexpression of Bc12 with low Myc expression correlated with resistance to radiation as shown by the extent of growth detected on day 14. Strong staining for Myc coupled with low or absent Bc12 expression generally correlated with radiosensitivity, although the level of p53 of the culture was critical in these cases. None of the proteins on their own correlated with radiation response. What appeared to be critical was the balance of cells expressing Bc12 and Myc proteins. Building on the results presented in a previous paper which showed a division of cultures from patients into those showing monotonic and nonmonotonic responses, this study presents results for explant cultures from a greater number of patients and attempts to characterize the profile of expression of the above proteins in the uroepithelium of these patients. It shows that high Bc12/Myc ratios were found in cultures which showed a non-monotonic and resistant dose response. Where Myc was the dominant protein in the culture postirradiation, a radiosensitive and monotonic response tended to occur. Since the proteins are being detected in the distant progeny of irradiated cells, it is likely that changes induced by radiation in the cell population are stable. The measurement of these two proteins can be made in cultured biopsy material and may therefore have predictive value in radiotherapy and radiation protection. Both normal and tumor biopsies from bladder mucosa showed similar correlations between Bc12/Myc ratios and growth postirradiation.

It has proved difficult to develop suitable models to study radiation-induced carcinogenesis by using human epithelial cells. However, immortalised human epithelial cell lines have proved useful. Unirradiated cells from the human keratinocyte cell line (HPV-G) and the human embryonic lung cell line (L132) were found to be tumourigenic in T-cell-deficient mice; thus, they are not suitable for transformation studies. Human urothelial cell lines (SV-HUC-1, NT11, BC16) and the human thyroid epithelial cell line (HTori-3) were nontumourigenic. The urothelial cell lines were refractory to radiation-induced carcinogenesis, and only one small tumour was observed in 57 mice that received irradiated cells. Whereas tumours were not produced following irradiation of these urothelial cells, changes in anchorage-independent growth were observed after a single dose of 8 Gy gamma-irradiation but not after 2 or 4 Gy. Irradiation of the human thyroid epithelial cell line (HTori-3) in vitro resulted in tumour formation. Passaging of the cells in vitro before injection did not seem to be critical. Some of the cell lines derived from the primary thyroid tumours exhibited p53 mutations in exons 5, 6, 7, and 8, as detected by single-stranded conformational polymorphism (SSCP) analysis. Thus, the human thyroid epithelial cell line (HTori-3) looks promising as a model for investigating the molecular events in radiation-induced carcinogenesis.

In this paper, an attempt is made to identify endpoints that might be of potential use in the quantification of radiation effects in human tissues. Irradiated cultures of cells that are not selected for clonogenic survival but are left in situ to grow after irradiation show a wide variety of morphological and biochemical abnormalities. These include nuclear fragmentation and other evidence of programmed cell death, but they also include a considerable amount of lysis, necrosis, and persistent abnormal growth and function, which are expressed in the progeny of irradiated cells. Induction of proteins associated with stress or shock responses, growth and cell cycle control, and control of apoptosis are also seen and may persist. The dose dependence of these various responses is documented, because it probably determines to a large extent the outcome of radiation exposure in terms of whether a cell dies, divides normally, or develops genomic instability, mutation, and ultimate carcinogenic progression of the progeny. Clearly, a cell that dies presents no further threat to the organism, nor does a fully repaired cell. Therefore, a major challenge facing radiation protection research is to define the population at risk of surviving with damage. The results show that there is a variation in response to radiation between different patient cultures that is detectable in an explant culture system of primary normal human urothelium. The growth pattern and protein expression postirradiation is consistent with apoptosis being a major determinant of low dose response to radiation. This form of death appears to be suppressed at higher doses and, in the majority of subjects, results in the presence of a highly abnormal population of cells, even though the population size is the same whether their progenitors were irradiated or not.

Purpose: Reports that the incorporation of exogenous oncogenes confer radioresistance have excited interest and controversy. We investigate whether human cell lines transformed to a malignant phenotype by gamma-rays or by chemicals became radioresistant., Materials and Methods: Rodent intestinal epithelial cells immortalized by the HPV virus, human immortalized bronchoepithelial cells and their malignant counterparts transformed by alpha-particles, uroepithelial cells and their malignant counterparts transformed either by alpha-particles or methylcholanthrine-4, and osteosarcoma cells and their nonmalignant counterparts into which the Rb gene had been introduced were used. Dose response curves for all of these cell lines were obtained by exposure to cesium 137 gamma-rays at a dose-rate of 1.18 Gy/min., Results: There was a dramatic increase in resistance to gamma-rays when H-ras was transfected into rodent intestinal epithelial cells. By contrast, in the case of the three human cell lines used, no consistent or significant change of radiosensitivity occurred when normal cells were transformed to a malignant state by alpha-particles or by a chemical carcinogen., Conclusions: Experiments involving the introduction of foreign oncogenes to cause tumorigenicity and accompanying radioresistance do not have direct relevance in human tumors. In a number of different instances, the conversion to malignancy by means that more closely reflect what happens in practice (i.e., by radiation or a chemical carcinogen) is not necessarily accompanied by an increased radioresistance to low doses of radiation.