Nickel-induced transcriptional memory in lung epithelial cells promotes interferon signaling upon nicotine exposure

Exposure to nickel, an environmental respiratory toxicant, is associated with lung diseases including asthma, pulmonary fibrosis, bronchitis and cancers. Our previous studies have shown that a majority of the nickel-induced transcriptional changes are persistent and do not reverse even after the termination of exposure. This suggested transcriptional memory, wherein the cell 'remembers' past nickel exposure. Transcriptional memory, due to which the cells respond more robustly to a previously encountered stimulus has been identified in a number of organisms. Therefore, transcriptional memory has been described as an adaptive mechanism. However, transcriptional memory caused by environmental toxicant exposures has not been well investigated. Moreover, how the transcriptional memory caused by an environmental toxicant might influence the outcome of exposure to a second toxicant has not been explored. In this study, we investigated whether nickel-induced transcriptional memory influences the outcome of the cell's response to a second respiratory toxicant, nicotine. Nicotine, an addictive compound in tobacco, is associated with the development of chronic lung diseases including chronic obstructive pulmonary disease (COPD) and pulmonary fibrosis. Our results show that nicotine exposure upregulated a subset of genes only in the cells previously exposed to nickel. Furthermore, our analyses indicate robust activation of interferon (IFN) signaling in these cells. IFN signaling is a driver of inflammation, which is associated with many chronic lung diseases. Therefore, our results suggest that nicotine exposure of lung cells that retain the transcriptional memory of previous nickel exposure could result in increased susceptibility to developing chronic inflammatory lung diseases.

Transcriptional repression of E-cadherin in nickel-exposed lung epithelial cells mediated by loss of Sp1 binding at the promoter

E-cadherin plays a central role in the stability of epithelial tissues by facilitating cell-cell adhesion. Loss of E-cadherin expression is a hallmark of epithelial-mesenchymal transition (EMT), a major event in the pathogenesis of several lung diseases. Our earlier studies showed that nickel, a ubiquitous environmental toxicant, induced EMT by persistently downregulating E-cadherin expression in human lung epithelial cells and that the EMT remained irreversible postexposure. However, the molecular basis of persistent E-cadherin downregulation by nickel exposure is not understood. Here, our studies show that the binding of transcription factor Sp1 to the promoter of E-cadherin encoding gene, CDH1, is essential for its expression. Nickel exposure caused a loss of Sp1 binding at the CDH1 promoter, resulting in its downregulation and EMT induction. Loss of Sp1 binding at the CDH1 promoter was associated with an increase in the binding of ZEB1 adjacent to the Sp1 binding site. ZEB1, an EMT master regulator persistently upregulated by nickel exposure, is a negative regulator of CDH1. CRISPR-Cas9-mediated knockout of ZEB1 restored Sp1 binding at the CDH1 promoter. Furthermore, ZEB1 knockout rescued E-cadherin expression and re-established the epithelial phenotype. Since EMT is associated with a number of nickel-exposure-associated chronic inflammatory lung diseases including asthma, fibrosis and cancer and metastasis, our findings provide new insights into the mechanisms associated with nickel pathogenesis.

Epithelial-mesenchymal transition: Insights into nickel-induced lung diseases

Nickel compounds are environmental toxicants, prevalent in the atmosphere due to their widespread use in several industrial processes, extensive consumption of nickel containing products, as well as burning of fossil fuels. Exposure to nickel is associated with a multitude of chronic inflammatory lung diseases including asthma, chronic obstructive pulmonary disease (COPD) and pulmonary fibrosis. In addition, nickel exposure is implicated in the development of nasal and lung cancers. Interestingly, a common pathogenic mechanism underlying the development of diseases associated with nickel exposure is epithelial-mesenchymal transition (EMT). EMT is a process by which the epithelial cells lose their junctions and polarity and acquire mesenchymal traits, including increased ability to migrate and invade. EMT is a normal and essential physiological process involved in differentiation, development and wound healing. However, EMT also contributes to a number of pathological conditions, including fibrosis, cancer and metastasis. Growing evidence suggest that EMT induction could be an important outcome of nickel exposure. In this review, we discuss the role of EMT in nickel-induced lung diseases and the mechanisms associated with EMT induction by nickel exposure.

Nickel-induced transcriptional changes persist post exposure through epigenetic reprogramming

Background

Nickel is an occupational and environmental toxicant associated with a number of diseases in humans including pulmonary fibrosis, bronchitis and lung and nasal cancers. Our earlier studies showed that the nickel-exposure-induced genome-wide transcriptional changes, which persist even after the termination of exposure may underlie nickel pathogenesis. However, the mechanisms that drive nickel-induced persistent changes to the transcriptome remain elusive.

Results

To elucidate the mechanisms that underlie nickel-induced long-term transcriptional changes, in this study, we examined the transcriptome and the epigenome of human lung epithelial cells during nickel exposure and after the termination of exposure. We identified two categories of persistently differentially expressed genes: (i) the genes that were differentially expressed during nickel exposure; and (ii) the genes that were differentially expressed only after the termination of exposure. Interestingly, > 85% of the nickel-induced gene expression changes occurred only after the termination of exposure. We also found extensive genome-wide alterations to the activating histone modification, H3K4me3, after the termination of nickel exposure, which coincided with the post-exposure gene expression changes. In addition, we found significant post-exposure alterations to the repressive histone modification, H3K27me3.

Conclusion

Our results suggest that while modest first wave of transcriptional changes occurred during nickel exposure, extensive transcriptional changes occurred during a second wave of transcription for which removal of nickel ions was essential. By uncovering a new category of transcriptional and epigenetic changes, which occur only after the termination of exposure, this study provides a novel understanding of the long-term deleterious consequences of nickel exposure on human health.

Cadmium exposure upregulates SNAIL through miR-30 repression in human lung epithelial cells

Cadmium (Cd) is a known human lung carcinogen. In addition, Cd exposure is associated with several lung diseases including emphysema, chronic obstructive pulmonary disease (COPD), asthma and fibrosis. Although earlier studies have identified several processes dysregulated by Cd exposure, the underlying mechanisms remain unclear. Here, we examined the transcriptome of lung epithelial cells exposed to Cd to understand the molecular basis of Cd-induced diseases. Computational analysis of the transcriptome predicted a significant number of Cd-upregulated genes to be targets of miR-30 family miRNAs. Experimental validation showed downregulation of all the miR-30 family members in Cd exposed cells. We found SNAIL, an EMT master regulator, to be the most upregulated among the miR-30 targets. Furthermore, we found decrease in the levels of epithelial marker E- cadherin (CDH1) and increase in the levels of mesenchymal markers, ZEB1 and vimentin. This suggested induction of EMT in Cd exposed cells. Luciferase reporter assays showed that miR-30 repressed SNAIL by directly targeting its 3' UTR. Over expression of miR-30e and transfection of miR-30e mimics reduced Cd-induced SNAIL upregulation. Our results suggest that miR-30 negatively regulates SNAIL in lung epithelial cells and that Cd-induced downregulation of miR-30 relieves this repression, resulting in SNAIL upregulation and EMT induction. EMT plays a major role in many diseases associated with Cd exposure including fibrosis, COPD, and cancer and metastasis. Therefore, our identification of miR-30 downregulation in Cd exposed cells and the consequent activation of SNAIL provides important mechanistic insights into lung diseases associated with Cd exposure.

Nickel exposure induces persistent mesenchymal phenotype in human lung epithelial cells through epigenetic activation of ZEB1

Nickel (Ni) is an environmental and occupational carcinogen, and exposure to Ni is associated with lung and nasal cancers in humans. Furthermore, Ni exposure is implicated in several lung diseases including chronic inflammatory airway diseases, asthma, and fibrosis. However, the mutagenic potential of Ni is low and does not correlate with its potent toxicity and carcinogenicity. Therefore, mechanisms underlying Ni exposure-associated diseases remain poorly understood. Since the health risks of environmental exposures often continue post exposure, understanding the exposure effects that persist after the termination of exposure could provide mechanistic insights into diseases. By examining the persistent effects of Ni exposure, we report that Ni induces epithelial-mesenchymal transition (EMT) and that the mesenchymal phenotype remains irreversible even after the termination of exposure. Ni-induced EMT was dependent on the irreversible upregulation of ZEB1, an EMT master regulator, via resolution of its promoter bivalency. ZEB1, upon activation, downregulated its repressors as well as the cell-cell adhesion molecule, E-cadherin, resulting in the cells undergoing EMT and switching to persistent mesenchymal status. ZEB1 depletion in cells exposed to Ni attenuated Ni-induced EMT. Moreover, Ni exposure did not induce EMT in ZEB1-depleted cells. Activation of EMT, during which the epithelial cells lose cell-cell adhesion and become migratory and invasive, plays a major role in asthma, fibrosis, and cancer and metastasis, lung diseases associated with Ni exposure. Therefore, our finding of irreversible epigenetic activation of ZEB1 by Ni exposure and the acquisition of persistent mesenchymal phenotype would have important implications in understanding Ni-induced diseases.

Identification of a unique gene expression signature in mercury and 2,3,7,8-tetrachlorodibenzo-p-dioxin co-exposed cells

Mercury (Hg) and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) are major environmental contaminants that commonly co-occur in the environment. Both Hg and TCDD are associated with a number of human diseases including cancers. While the individual toxicological effects of Hg and TCDD have been extensively investigated, studies on co-exposure are limited to a few genes and pathways. Therefore, a significant knowledge gap exists in the understanding of the deleterious effects of co-exposure to Hg and TCDD. Due to the prevalence of Hg and TCDD co-contamination in the environment and the major human health hazards they pose, it is important to obtain a fuller understanding of genome-wide effects of Hg and TCDD co-exposure. In this study, by performing a comprehensive transcriptomic analysis of human bronchial epithelial cells (BEAS-2B) exposed to Hg and TCDD individually and in combination, we have uncovered a subset of genes with altered expression only in the co-exposed cells. We also identified the additive as well as antagonistic effects of Hg and TCDD on gene expression. Moreover, we found that co-exposure impacted several biological and disease processes not affected by Hg or TCDD individually. Our studies show that the consequences of Hg and TCDD co-exposure on the transcriptional program and biological processes could be substantially different from single exposures, thus providing new insights into the co-exposure-specific pathogenic processes.

Nuclear Factor κB1/RelA Mediates Inflammation in Human Lung Epithelial Cells at Atmospheric Oxygen Levels

Oxygen levels range from 2% to 9% in vivo. Atmospheric O2 levels (21%) are known to induce cell proliferation defects and cellular senescence in primary cell cultures. However, the mechanistic basis of the deleterious effects of higher O2 levels is not fully understood. On the other hand, immortalized cells including cancer cell lines, which evade cellular senescence are normally cultured at 21% O2 and the effects of higher O2 on these cells are understudied. Here, we addressed this problem by culturing immortalized human bronchial epithelial (BEAS-2B) cells at ambient atmospheric, 21% O2 and lower, 10% O2. Our results show increased inflammatory response at 21% O2 but not at 10% O2. We found higher RelA binding at the NF-κB1/RelA target gene promoters as well as upregulation of several pro-inflammatory cytokines in cells cultured at 21% O2. RelA knockdown prevented the upregulation of the pro-inflammatory cytokines at 21% O2, suggesting NF-κB1/RelA as a major mediator of inflammatory response in cells cultured at 21% O2. Interestingly, unlike the 21% O2 cultured cells, exposure of 10% O2 cultured cells to H2O2 did not elicit inflammatory response, suggesting increased ability to tolerate oxidative stress in cells cultured at lower O2 levels.

Connective Tissue Growth Factor (CTGF/CCN2) enhances lactogenic differentiation of mammary epithelial cells via integrin-mediated cell adhesion

Background

Connective Tissue Growth Factor (CTGF/CCN2), a known matrix-associated protein, is required for the lactogenic differentiation of mouse mammary epithelial cells. An HC11 mammary epithelial cell line expressing CTGF/CCN2 was constructed to dissect the cellular responses to CTGF/CCN2 that contribute to this differentiation program.

Results

Tetracycline-regulated expression of CTGF/CCN2 in HC11 cells enhanced multiple markers of lactogenic differentiation including β-casein transcription and mammosphere formation. In a separate measure of mammary differentiation the addition of CTGF/CCN2 to cultures of MCF10A cells increased the development of acini in vitro. In HC11 cells the elevated levels of CTGF/CCN2 diminished the requirement for extracellular matrix proteins in the activation of β-casein transcription, indicating that CTGF/CCN2 contributed to lactogenic differentiation through the regulation of matrix dependent cell adhesion. CTGF/CCN2 expression in HC11 cells increased expression of extracellular matrix proteins and integrins, enhanced the formation of focal adhesion complexes, and increased survival signaling. In addition, HC11 cells adhered to immobilized CTGF/CCN2 and this was inhibited by function-blocking antibodies to the integrins α6 and β1, and to a lesser degree by antibody to β3 integrin.

Conclusions

CTGF/CCN2 expression in HC11 cells led to an increase in multiple markers of lactogenic differentiation. The mechanisms by which CTGF/CCN2 contributed to lactogenic differentiation include direct binding of CTGF/CCN2 to integrin complexes and CTGF/CCN2-induced matrix protein expression resulting in elevated integrin functionality.

Glucocorticoid induced expression of connective tissue growth factor contributes to lactogenic differentiation of mouse mammary epithelial cells

The response of mammary epithelial cells to basement membrane and stroma induced signals contributes to the degree of differentiation in this tissue. The studies reported here indicate that connective tissue growth factor (CTGF) is highly elevated during lactogenic differentiation of the HC11 mouse mammary epithelial cell line. In addition, CTGF is expressed in the mouse mammary gland during pregnancy and lactation and it is expressed in primary mammary epithelial cell cultures established from pregnant mice. In HC11 cells CTGF is transcriptionally regulated by dexamethasone, but not by estrogen or progesterone, and CTGF expression is not dependent on TGFbeta. CTGF contributes to and is required for lactogenic differentiation of HC11 cells, as demonstrated by increased differentiation following expression of plasmid-encoded CTGF and decreased differentiation following depletion of endogenous CTGF with siRNA. Moreover, HC11 mouse mammary epithelial cells infected with an adenoviral vector encoding CTGF exhibit increased lactogenic differentiation. Plasmid vector-induced elevation of CTGF levels also increased the level of beta1 integrin in HC11 cells. Because the production of stromal factors is an important component of differentiation in mammary epithelial cells, the regulation of CTGF by glucocorticoids may play a critical role in this aspect of the control of differentiation. The studies reported here provide important information on the role of CTGF in mammary epithelial cell differentiation.

EGF-induced activation of Akt results in mTOR-dependent p70S6 kinase phosphorylation and inhibition of HC11 cell lactogenic differentiation

BACKGROUND

HC11 mouse mammary epithelial cells differentiate in response to lactogenic hormone resulting in expression of milk proteins including beta-casein. Previous studies have shown that epidermal growth factor (EGF) blocks differentiation not only through activation of the Ras/Mek/Erk pathway but also implicated phosphatidylinositol-3-kinase (PI-3-kinase) signaling. The current study analyzes the mechanism of the PI-3-kinase pathway in an EGF-induced block of HC11 lactogenic differentiation.

RESULTS

HC11 and HC11-luci cells, which contain luciferase gene under the control of a beta-casein promotor, were treated with specific chemical inhibitors of signal transduction pathways or transiently infected/transfected with vectors encoding dominant negative-Akt (DN-Akt) or conditionally active-Akt (CA-Akt). The expression of CA-Akt inhibited lactogenic differentiation of HC11 cells, and the infection with DN-Akt adenovirus enhanced beta-casein transcription and rescued beta-casein promotor-regulated luciferase activity in the presence of EGF. Treatment of cells with Rapamycin, an inhibitor of mTOR, blocked the effects of EGF on beta-casein promotor driven luciferase activity as effectively as PI-3-kinase inhibitors. While expression of CA-Akt caused a constitutive activation of p70S6 kinase (p70S6K) in HC11 cells, the inhibition of either PI-3-kinase or mTOR abolished the activation of p70S6K by EGF. The activation of p70S6K by insulin or EGF resulted in the phosphorylation of ribosomal protein S6 (RPS6), elongation initiation factor 4E (elF4E) and 4E binding protein1 (4E-BP1). But lower levels of PI-3-K and mTOR inhibitors were required to block insulin-induced phosphorylation of RPS6 than EGF-induced phosphorylation, and insulin-induced phosphorylation of elF4E and 4E-BP1 was not completely mTOR dependent suggesting some diversity of signaling for EGF and insulin. In HC11 cells undergoing lactogenic differentiation the phosphorylation of p70S6K completely diminished by 12 hours, and this was partly attributable to dexamethasone, a component of lactogenic hormone mix. However, p70S6K phosphorylation persisted in the presence of lactogenic hormone and EGF, but the activation could be blocked by a PI-3-kinase inhibitor.

CONCLUSION

PI-3-kinase signaling contributes to the EGF block of lactogenic differentiation via Akt and p70S6K. The EGF-induced activation of PI-3-kinase-Akt-mTOR regulates phosphorylation of molecules including ribosomal protein S6, eIF4E and 4E-BP1 that influence translational control in HC11 cells undergoing lactogenic differentiation.

Hypofractionated radiotherapy for patients with carcinoma of the bladder

In order to develop a low toxicity regimen of bladder radiotherapy for the palliation of patients with poor performance status we carried out a Phase II study of weekly 6 Gy fractions to a maximum dose of 30-36 Gy in 65 patients with T(2)-T(4) bladder cancer (median age 81 years). A complete response was obtained in 23/37 (62%) assessable patients at cystoscopy. Local control was achieved in 16/65 (25%) patients. The median survival of all 65 patients was 35 weeks, and the 2-year actuarial survival 21%. The main acute toxicity was urinary frequency as often as hourly at the peak of the reaction (Radiation Therapy Oncology Group (RTOG) grade 3) in seven patients, and urinary obstruction (RTOG grade 4) in one. The reactions may have been compounded by the effects of locally advanced tumour. Late bladder toxicity amongst the 16 patients who were evaluable after 1 year included four patients with persisting frequency, one with severe haematuria (RTOG grade), and one with a bladder capacity <100 ml (RTOG grade 4). One patient experienced RTOG grade 4 late bowel and bladder morbidity. Weekly 6 Gy fractions to a total dose of 30-36 Gy is a satisfactory palliative regimen for patients with advanced bladder cancer who cannot tolerate standard radical radiotherapy, but it may produce significant late bladder morbidity.

Set-up variation of patients treated with radiotherapy to the prostate measured with an electronic portal imaging device

The set-up variation of 11 patients treated supine with radical radiotherapy for carcinoma of the prostate was measured with an electronic portal imaging device to determine the adequacy of set-up techniques and current margins, as well as the need for immobilization. During the treatments 172 images of the anterior fields and 159 images of the left-lateral fields were taken and the errors in treatment placement were measured by template matching. The variation in the superior-inferior direction was small, 1.4-1.6 mm (1 SD), while the medio-lateral variation was 2.8 mm (1 SD). The anterior-posterior variation was largest, 4.6 mm (1 SD) with an offset of 3.3 mm anterior. This anterior offset and large anterior-posterior variation suggests that set-up techniques were not optimal for this direction. The 1 cm margin used was adequate for set-up variation except in a small number of cases, which was mainly due to the anterior trend. Random (treatment-to-treatment) variations were small (1.1-2.3 mm; 1 SD), indicating that immobilization would result in only modest improvement in reproducibility for these supine patients.

Comparison of two methods for anterior-posterior isocenter localization in pelvic radiotherapy using electronic portal imaging

PURPOSE

The two setup methods commonly used to determine the anterior-posterior isocenter location in pelvic radiotherapy are to align lateral localization lasers with lateral skin tattoos on the patient, or to set the couch height so that the isocenter is at a fixed height (determined during simulation or treatment planning) above the couch top. This study was implemented to determine which technique gives more accurate patient treatment by comparison of the anterior-posterior setup variation measured with electronic portal imaging.

METHODS AND MATERIALS

Eleven supine prostate patients were treated with tattoo localization and 159 left-lateral portal images were taken during the treatments. The field displacements were then determined by template matching. These patients were compared to nine patients (205 images) set up to a fixed isocenter height. Similarly, eight prone rectal patients (136 right-lateral images) set up to tattoos were compared to six patients (108 images) set up to a fixed height. The patients were not immobilized and were all treated with three field techniques on a hard couch top. The overall mean treatment position deviation and the standard deviation of the displacements (total setup variation) were calculated for each patient group along with the systematic (simulator-to-treatment) and the random (treatment-to-treatment) setup variation.

RESULTS

The mean treatment position deviations were 3.3 mm anterior and 5.2 mm posterior with the tattoo method for the prostate and rectal patients, respectively. These mean position deviations were 0.4/0.1 mm anterior with the fixed height technique. The total setup variations were 4.6/5.2 mm (1 SD) with tattoo localization and 1.7/1.5 mm (1 SD) with the fixed height method. Similarly, random variation was 2.3/3.3 mm (1 SD) with the tattoo method compared to 1.3/1.2 mm (1 SD) with the fixed height method. Systematic variation was 3.7/4.5 mm (1 SD) compared to 1.2/1.1 mm (1 SD).

CONCLUSION

The fixed height technique gives much more accurate localization of the anterior-posterior isocenter in pelvic radiotherapy than lateral skin tattoos.

Craniopharyngioma--a long-term results following limited surgery and radiotherapy

Between 1950 and 1986 173 patients with craniopharyngioma were treated at the Royal Marsden Hospital with external beam radiotherapy either alone or following surgery. Four patients had complete tumour excision, 21 subtotal and 78 partial resection, 14 had biopsy alone, 34 aspiration alone and 22 had no surgery directed at tumour eradication. Seventy-seven (45%) were children (aged < 16 years). The 10 and 20 year progression-free survival (PFS) rates were 83% and 79%. There were no independent prognostic factors for PFS. The 10 and 20 year survival rates were 77% and 66% at a median follow-up of 12 years. After adjustment for mortality in the normal population, age and technique of radiotherapy (which corresponded with era of treatment) were significant independent prognostic factors for survival. The risk of death (corrected for mortality from natural causes and controlling for radiotherapy technique) for age groups 16-39 and > or = 40 was 0.58 and 0.40 respectively, relative to a risk of 1.0 for the age group < 16 years. Survival and PFS were not influenced by the extent of surgical excision. Visual field defect improved after radiotherapy in 36% of patients (38/106) and visual acuity in 30% (27/91). No patient developed radiation optic neuropathy. We conclude that limited surgery and radiotherapy achieve excellent long-term tumour control and survival with low morbidity.

Radiotherapy for the treatment of recurrent craniopharyngioma

Twenty-five patients with craniopharyngioma received radiotherapy at the time of recurrence. The 10-year progression free survival and survival from the time of recurrence were 72% and 77% respectively. Nineteen patients underwent surgery prior to radiotherapy (6 partial excision, 4 decompression and 9 cyst aspiration). The extent of resection at the time of recurrence did not influence the outcome. Apart from pituitary failure there was no serious morbidity associated with this approach. The results of radiotherapy at recurrence are similar to those of conservative surgery and radiotherapy at the time of presentation. It suggests that radiotherapy remains an effective treatment modality at the time of recurrence of craniopharyngioma and it may therefore be delayed in situations where immediate radiation is not advisable. However, the high recurrence rate in incompletely excised craniopharyngioma, together with the potential risk of additional morbidity and mortality from undiagnosed progressive tumour and salvage surgery, would argue for a policy of radiotherapy as part of the initial treatment of incompletely excised craniopharyngioma.

Primary small intestinal lymphoma

Gastro-intestinal tract is the most common site of extranodal presentation in non-Hodgkin's lymphoma. Among the subsites the small intestine predominates. This paper presents a review of 21 cases of primary gastro-intestinal lymphoma seen at the Department of Radiation Oncology, Christian Medical College, Vellore, during the period 1979-1986. All patients had laparotomy, and biopsy from the primary site. Histopathological subtypes were done in the International Working Formulation. Stage groupings were done applying the Crowther and Blackledge staging system. Post-laparotomy treatment decision was made depending on the patient's general condition, completeness of surgery and histological subtype. The overall survival rate was 31.5% at 5 years. Early stage disease and high-grade lymphomas have a better prognosis if treated adequately.

Hyperfractionation in advanced carcinoma of the uterine cervix: a preliminary report

Experience with twice-a-day radiation therapy program for carcinoma of the uterine cervix (FIGO Stages IIB, IIIA & IIIB) is presented. The program consists of delivering 120 cGy per fraction, two fractions a day with 6 hours between fractions. A total of 6000 cGy was delivered in 50 fractions over 5 weeks. A control group was given conventional fractionation 5000 cGy in 25 fractions, 200 cGy per fraction over 5 weeks. This feasibility study enrolled 30 patients, 15 in each group. Normal tissue reactions in skin, mucosa and bowel were recorded. The acute normal tissue reactions were enhanced in the hyperfractionation group. This was significant with regard to the bowel complications. The tumor control rate did not show any significant difference between the two groups. A short follow-up period has revealed complete healing of all acute normal tissue reactions. This study shows that further dose escalation is feasible and a study with large sample size and longer follow-up is required to reach definite conclusions.

Ovarian and testicular damage by cytotoxic drugs

The use of cytotoxic drugs has improved the survival figures in malignancies. These drugs exert harmful effects on the tumour cell and normal cells as well. The detrimental effects on gonads were studied in 36 patients who had cytotoxic chemotherapy for various malignancies. In Group I (20 adults in clinical remission after chemotherapy), sterility was noted in 93.7% of men and hundred percent of women experienced irregularly mensus during treatment, 50% of them subsequently developing persistent amenorrhoea. In Group II, (16 adults undergoing chemotherapy) 100% of men had oligospermia, with 75% of them developing azoospermia after 2-3 cycles of treatment. Women also showed similar effect, but were less vulnerable than men.

Pulmonary metastases from ameloblastoma of the mandible treated with cisplatin, adriamycin, and cyclophosphamide

A case of delayed pulmonary metastases from an ameloblastoma of the mandible, which occurred 20 years after surgical resection of the primary tumor but with no recurrence at the primary site, is reported. Combination chemotherapy using cisplatin, adriamycin, and cyclophosphamide has produced a very good clinical and radiologically documented response in this case.