Multiple sclerosis health-related quality of life utility values from the UK MS register.

Background: New interventions for multiple sclerosis (MS) commonly require a demonstration of cost-effectiveness using health-related quality of life (HRQoL) utility values. The EQ-5D is the utility measure approved for use in the UK NHS funding decision-making. There are also MS-specific utility measures - e.g., MS Impact Scale Eight Dimensions (MSIS-8D) and MSIS-8D-Patient (MSIS-8D-P). Objectives: Provide EQ-5D, MSIS-8D and MSIS-8D-P utility values from a large UK MS cohort and investigate their association with demographic/clinical characteristics. Methods: UK MS Register data from 14,385 respondents (2011 to 2019) were analysed descriptively and using multivariable linear regression, with self-report Expanded Disability Status Scale (EDSS) scores. Results: The EQ-5D and MSIS-8D were both sensitive to differences in demographic/clinical characteristics. An inconsistency found in previous studies whereby mean EQ-5D values were higher for an EDSS score of 4 rather than 3 was not observed. Similar utility values were observed between MS types at each EDSS score. Regression showed EDSS score and age were associated with utility values from all three measures. Conclusions: This study provides generic and MS-specific utility values for a large UK MS sample, with the potential for use in cost-effectiveness analyses of treatments for MS.

Feasibility of tumour-focused adaptive radiotherapy for bladder cancer on the MR-linac.

Bladder tumour-focused magnetic resonance image-guided adaptive radiotherapy using a 1.5 Tesla MR-linac is feasible. A full online workflow adapting to anatomy at each fraction is achievable in approximately 30 min. Intra-fraction bladder filling did not compromise target coverage with the class solution employed.

Vestibular rehabilitation in multiple sclerosis: study protocol for a randomised controlled trial and cost-effectiveness analysis comparing customised with booklet based vestibular rehabilitation for vestibulopathy and a 12 month observational cohort study of the symptom reduction and recurrence rate following treatment for benign paroxysmal positional vertigo.

BACKGROUND: Symptoms arising from vestibular system dysfunction are observed in 49-59% of people with Multiple Sclerosis (MS). Symptoms may include vertigo, dizziness and/or imbalance. These impact on functional ability, contribute to falls and significant health and social care costs. In people with MS, vestibular dysfunction can be due to peripheral pathology that may include Benign Paroxysmal Positional Vertigo (BPPV), as well as central or combined pathology. Vestibular symptoms may be treated with vestibular rehabilitation (VR), and with repositioning manoeuvres in the case of BPPV. However, there is a paucity of evidence about the rate and degree of symptom recovery with VR for people with MS and vestibulopathy. In addition, given the multiplicity of symptoms and underpinning vestibular pathologies often seen in people with MS, a customised VR approach may be more clinically appropriate and cost effective than generic booklet-based approaches. Likewise, BPPV should be identified and treated appropriately. METHODS/ DESIGN: People with MS and symptoms of vertigo, dizziness and/or imbalance will be screened for central and/or peripheral vestibulopathy and/or BPPV. Following consent, people with BPPV will be treated with re-positioning manoeuvres over 1-3 sessions and followed up at 6 and 12 months to assess for any re-occurrence of BPPV. People with central and/or peripheral vestibulopathy will be entered into a randomised controlled trial (RCT). Trial participants will be randomly allocated (1:1) to either a 12-week generic booklet-based home programme with telephone support or a 12-week VR programme consisting of customised treatment including 12 face-to-face sessions and a home exercise programme. Customised or booklet-based interventions will start 2 weeks after randomisation and all trial participants will be followed up 14 and 26 weeks from randomisation. The primary clinical outcome is the Dizziness Handicap Inventory at 26 weeks and the primary economic endpoint is quality-adjusted life-years. A range of secondary outcomes associated with vestibular function will be used. DISCUSSION: If customised VR is demonstrated to be clinically and cost-effective compared to generic booklet-based VR this will inform practice guidelines and the development of training packages for therapists in the diagnosis and treatment of vestibulopathy in people with MS. TRIAL REGISTRATION: ISRCTN Number: 27374299 Date of Registration 24/09/2018 Protocol Version 15 25/09/2019.

Using the Fatigue Severity Scale to inform healthcare decision-making in multiple sclerosis: mapping to three quality-adjusted life-year measures (EQ-5D-3L, SF-6D, MSIS-8D).

BACKGROUND: Fatigue has a major influence on the quality of life of people with multiple sclerosis. The Fatigue Severity Scale is a frequently used patient-reported measure of fatigue impact, but does not generate the health state utility values required to inform cost-effectiveness analysis, limiting its applicability within decision-making contexts. The objective of this study was to use statistical mapping methods to convert Fatigue Severity Scale scores to health state utility values from three preference-based measures: the EQ-5D-3L, SF-6D and Multiple Sclerosis Impact Scale-8D. METHODS: The relationships between the measures were estimated through regression analysis using cohort data from 1056 people with multiple sclerosis in South West England. Estimation errors were assessed and predictive performance of the best models as tested in a separate sample (n = 352). RESULTS: For the EQ-5D and the Multiple Sclerosis Impact Scale-8D, the best performing models used a censored least absolute deviation specification, with Fatigue Severity Scale total score, age and gender as predictors. For the SF-6D, the best performing model used an ordinary least squares specification, with Fatigue Severity Scale total score as the only predictor. CONCLUSIONS: Here we present algorithms to convert Fatigue Severity Scales scores to health state utility values based on three preference-based measures. These values may be used to estimate quality-adjusted life-years for use in cost-effectiveness analyses and to consider the health-related quality of life of people with multiple sclerosis, thereby informing health policy decisions.

Increased carrier mobility and lifetime in CdSe quantum dot thin films through surface trap passivation and doping.

Passivating surface defects and controlling the carrier concentration and mobility in quantum dot (QD) thin films is prerequisite to designing electronic and optoelectronic devices. We investigate the effect of introducing indium in CdSe QD thin films on the dark mobility and the photogenerated carrier mobility and lifetime using field-effect transistor (FET) and time-resolved microwave conductivity (TRMC) measurements. We evaporate indium films ranging from 1 to 11 nm in thickness on top of approximately 40 nm thick thiocyanate-capped CdSe QD thin films and anneal the QD films at 300 °C to densify and drive diffusion of indium through the films. As the amount of indium increases, the FET and TRMC mobilities and the TRMC lifetime increase. The increase in mobility and lifetime is consistent with increased indium passivating midgap and band-tail trap states and doping the films, shifting the Fermi energy closer to and into the conduction band.

A cumulative dose, safety and tolerability study of arformoterol in pediatric subjects with stable asthma.

PURPOSE: Short-acting ß(2) -agonists (SABAs) are recommended for treating acute pediatric asthma. The long-acting ß(2) -agonist (LABA) arformoterol is approved for the maintenance treatment of chronic obstructive pulmonary disease (COPD). Arformoterol acts rapidly, is delivered via nebulization, and, as such, raises concerns from the FDA over possible off-label use in acute asthma in children. As a step to investigate this issue, this study evaluated the safety and tolerability of three consecutive doses of arformoterol administered over 1 hr in children with stable asthma. METHODS: This study consisted of a double-blind, crossover period in which subjects (ages 2-11 years) with stable asthma were randomized to three consecutive nebulized doses of arformoterol (7.5 µg/dose) or levalbuterol (0.63 mg/dose) administered over 1-hr (0, 30, and 60 min) followed by an open-label period with three consecutive doses of arformoterol (15 µg/dose) administered over 1 hr. Endpoints were change in heart rate, blood pressure, and serum potassium and glucose levels. Other endpoints included adverse events and pulmonary function. RESULTS: There were no clinically important mean changes from pre-dose in heart rate, blood pressure, or serum glucose levels, across treatment groups. Substantial declines in serum potassium levels were observed both 2 and 6 hr post-dosing. Two subjects had declines to 2.8 mEq/L and 2.9 mEq/L 2-hr post-dosing. Adverse events were infrequent and differences in forced expiratory volume in 1 sec and peak expiratory flow across treatment groups were not clinically meaningful. CONCLUSION: In this study, in children with stable asthma, three consecutive doses of arformoterol (7.5 and 15 µg) and levalbuterol were overall well tolerated. Nonetheless, serum potassium levels demonstrated substantial mean declines after dosing. These findings do not address or support the safety and tolerability of arformoterol use in acute exacerbations of asthma in children.

Effects of arformoterol twice daily, tiotropium once daily, and their combination in patients with COPD.

PURPOSE: Current guidelines support using in combination more than one class of long-acting bronchodilator for COPD patients whose symptoms are not controlled by mono-therapy. This 2-week, multi-center (34 sites), randomized, modified-blind, parallel group study evaluated the efficacy and safety of concomitant treatment with nebulized arformoterol (the formoterol(R,R)-isomer) BID and tiotropium DPI QD. METHODS: COPD patients (mean FEV(1) 1.37L, 45.4% predicted) were randomized to receive mono-therapy (either arformoterol 15microg BID [n=76] or tiotropium 18microg QD [n=80]), or combined therapy (sequential dosing of arformoterol 15microg BID and tiotropium 18microg QD [n=78]). Changes in pulmonary function, dyspnea, and rescue levalbuterol use were evaluated, as were safety outcomes. RESULTS: Mean FEV(1)AUC(0-24) (the primary endpoint) improved similarly from baseline for arformoterol (0.10L) and tiotropium (0.08L) treatment groups and greater for the combined therapy group (0.22L; all p-values <0.005). Peak FEV(1), peak FVC, 24-h trough FEV(1), and inspiratory capacity also improved similarly for the mono-therapies and greatest for the combined therapy. Dyspnea (mean transition dyspnea index) improved similarly for arformoterol (+2.3) and tiotropium (+1.8) and greatest with combined therapy (+3.1; p-values <0.05). Levalbuterol use decreased for all treatment groups (range -1.8 to -2.5 actuations/day). All treatments had similar frequency of adverse events. CONCLUSION: In this study, the combination of nebulized arformoterol 15microg BID plus tiotropium 18microg DPI QD was the most effective in improving pulmonary function and disease symptoms. Mono-therapy improvement with arformoterol or tiotropium was similar. All three treatments were well tolerated.

DNA-PKcs and ATM influence generation of ionizing radiation-induced bystander signals.

The phenomenon by which irradiated cells influence non-irradiated neighboring cells, referred to as the bystander effect (BSE), is not well understood in terms of the underlying pathways involved. We sought to enlighten connections between DNA damage repair and the BSE. Utilizing sister chromatid exchange (SCE) frequencies as a marker of the BSE, we performed cell transfer strategies that enabled us to distinguish between generation versus reception of a bystander signal. We find that DNA-dependent Protein Kinase catalytic subunit (DNA-PKcs) and Ataxia Telangectasia Mutated (ATM) are necessary for the generation of such a bystander signal in normal human cells following gamma (gamma)-ray exposure, but are not required for its reception. Importantly, we also show that directly irradiated human cells do not respond to receipt of a bystander signal, helping to explain why the BSE is a low-dose phenomenon. These studies provide the first evidence for a role of the DNA damage response proteins DNA-PKcs and ATM specifically in the generation of a bystander signal and intercellular signaling.

Arformoterol and salmeterol in the treatment of chronic obstructive pulmonary disease: a one year evaluation of safety and tolerance.

INTRODUCTION: Concerns have been raised regarding the safety of extended use of long-acting beta2-agonists (LABAs). The safety of arformoterol (50 microg QD), and salmeterol (42 microg BID), was assessed over 12 months in subjects with COPD. The study also examined the occurrence of tolerance with these agents, i.e. whether improvement in airway function diminished or frequency of exacerbations increased with 12-months of use. METHODS: Subjects with COPD (mean FEV1 1.2 L, ~41% predicted) were enrolled in the study and randomized to receive nebulized arformoterol 50 microg QD (n = 528) or salmeterol 42 microg BID (MDI; n = 265) in a prospective, multicenter, open-label, 12-month trial. The frequency of adverse events, COPD exacerbations, and use of short-acting bronchodilator agents were assessed throughout the study period. Pulmonary function was also examined. RESULTS: Among treated subjects, the frequency of adverse events was similar for those taking arformoterol (90.5%) and salmeterol (88.3%). Tremor was more frequent among subjects treated with arformoterol (13.4%) than those treated with salmeterol (1.1%). The frequency of COPD exacerbations did not increase over 12 months for arformoterol and salmeterol (weeks 0-13: 15.7% and 11.7%, respectively; weeks 39-52: 10.0% and 9.4%, respectively). Supplemental ipratropium bromide and rescue racemic albuterol use decreased for both groups by 0.8 to 1.5 actuations/day, decreases that remained stable throughout the 52-week study. Mean predose (trough) FEV1 improved for arformoterol and salmeterol at week 13 (7.1% +/- 17.0 and 7.6% +/- 17.8, respectively) and the improvement continued at week 52 (5.9% and 6.2%, respectively). Mean peak percent predicted postdose FEV1 over the course of the 52-week study declined by about 2% for both treatments, but throughout was higher for arformoterol than for salmeterol. CONCLUSION: In this trial, both arformoterol 50 microg QD and salmeterol 42 microg BID were well tolerated in patients with COPD. Both LABAs produced effective bronchodilation and their use was not associated with the development of clinically meaningful tolerance over a 1-year treatment period.

Ultra-violet light induced changes in DNA dynamics may enhance TT-dimer recognition.

Short-wave ultra-violet light promotes the formation of DNA dimers between adjacent thymine bases, and if unrepaired these dimers may induce skin cancer. Living cells have a very robust repair system capable of repairing hundreds of lesions every day. Although many of the details of the dimer repair mechanism are known, it is still a mystery how the dimers are recognized. Because the dimers are hidden from repair proteins diffusing in the cell nucleus, it has been surmised that dimer recognition is indirect. In this paper, a new recognition signal is suggested by a theory of the dimer-induced large amplitude, prolonged oscillations in the motion of the two strands in double-stranded DNA molecules. These large amplitude oscillations of the two DNA strands, localized around the dimer will unveil the dimer allowing the repair proteins to bind to the dimer site. The temperature dependence of the recognition rate is correlated with the inter-strand fluctuations and must decrease with decreasing temperature according to the findings in this paper. Moreover the probability for finding a large opening is localized to the dimer neighbourhood and these large openings may play an important role in dimer-repair protein biochemistry.

Testosterone replacement therapy improves insulin resistance, glycaemic control, visceral adiposity and hypercholesterolaemia in hypogonadal men with type 2 diabetes.

OBJECTIVE: Low levels of testosterone in men have been shown to be associated with type 2 diabetes, visceral adiposity, dyslipidaemia and metabolic syndrome. We investigated the effect of testosterone treatment on insulin resistance and glycaemic control in hypogonadal men with type 2 diabetes. DESIGN: This was a double-blind placebo-controlled crossover study in 24 hypogonadal men (10 treated with insulin) over the age of 30 years with type 2 diabetes. METHODS: Patients were treated with i.m. testosterone 200 mg every 2 weeks or placebo for 3 months in random order, followed by a washout period of 1 month before the alternate treatment phase. The primary outcomes were changes in fasting insulin sensitivity (as measured by homeostatic model index (HOMA) in those not on insulin), fasting blood glucose and glycated haemoglobin. The secondary outcomes were changes in body composition, fasting lipids and blood pressure. Statistical analysis was performed on the delta values, with the treatment effect of placebo compared against the treatment effect of testosterone. RESULTS: Testosterone therapy reduced the HOMA index (-1.73 +/- 0.67, P = 0.02, n = 14), indicating an improved fasting insulin sensitivity. Glycated haemoglobin was also reduced (-0.37 +/- 0.17%, P = 0.03), as was the fasting blood glucose (-1.58 +/- 0.68 mmol/l, P = 0.03). Testosterone treatment resulted in a reduction in visceral adiposity as assessed by waist circumference (-1.63 +/- 0.71 cm, P = 0.03) and waist/hip ratio (-0.03 +/- 0.01, P = 0.01). Total cholesterol decreased with testosterone therapy (-0.4 +/- 0.17 mmol/l, P = 0.03) but no effect on blood pressure was observed. CONCLUSIONS: Testosterone replacement therapy reduces insulin resistance and improves glycaemic control in hypogonadal men with type 2 diabetes. Improvements in glycaemic control, insulin resistance, cholesterol and visceral adiposity together represent an overall reduction in cardiovascular risk.

Strand-specific fluorescence in situ hybridization: the CO-FISH family.

The ability to prepare single-stranded chromosomal target DNA allows innovative uses of FISH technology for studies of chromosome organization. Standard FISH methodologies require functionally single-stranded DNAs in order to facilitate hybridization between the probe and the complementary chromosomal target sequence. This usually involves denaturation of double-stranded probes to induce temporary separation of the DNA strands. Strand-specific FISH (CO-FISH; Chromosome Orientation-FISH) involves selective removal of newly replicated strands from DNA of metaphase chromosomes which results in single-stranded target DNA. When single-stranded probes are then hybridized to such targets, the resulting strand-specific hybridization is capable of revealing a level of information previously unattainable at the cytogenetic level. Mammalian telomeric DNA consists of tandem repeats of the (TTAGGG) sequence, oriented 5'-->3' towards the termini of all vertebrate chromosomes. Based on this conserved structural organization, CO-FISH with a telomere probe reveals the absolute 5'-->3' orientation of DNA sequences with respect to the pter-->qter direction of chromosomes. Development and various applications of CO-FISH will be discussed: detection of cryptic inversions, discrimination between telomeres produced by leading- versus lagging-strand synthesis, and replication timing of mammalian telomeres.

DNA and telomeres: beginnings and endings.

How a cell deals with its DNA ends is a question that returns us to the very beginnings of modern telomere biology. It is also a question we are still asking today because it is absolutely essential that a cell correctly distinguishes between natural chromosomal DNA ends and broken DNA ends, then processes each appropriately - preserving the one, rejoining the other. Effective end-capping of mammalian telomeres has a seemingly paradoxical requirement for proteins more commonly associated with DNA double strand break (DSB) repair. Ku70, Ku80, DNA-PKcs (the catalytic subunit of DNA-dependent protein kinase), Xrcc4 and Artemis all participate in DSB repair through nonhomologous end-joining (NHEJ). Somewhat surprisingly, mutations in any of these genes cause spontaneous chromosomal end-to-end fusions that maintain large blocks of telomeric sequence at the points of fusion, suggesting loss or failure of a critical terminal structure, rather than telomere shortening, is at fault. Nascent telomeres produced via leading-strand DNA synthesis are especially susceptible to these end-to-end fusions, suggesting a crucial difference in the postreplicative processing of telomeres that is linked to their mode of replication. Here we will examine the dual roles played by DNA repair proteins. Our review of this rapidly advancing field primarily will focus on mammalian cells, and cannot include even all of this. Despite these limitations, we hope the review will serve as a useful gateway to the literature, and will help to frame the major issues in this exciting and rapidly progressing field. Our apologies to those whose work we are unable to include.

Caenorhabditis elegans MES-3 is a target of GLD-1 and functions epigenetically in germline development.

The maternal-effect sterile (MES) proteins are maternally supplied regulators of germline development in Caenorhabditis elegans. In the hermaphrodite progeny from mes mutant mothers, the germline dies during larval development. On the basis of the similarities of MES-2 and MES-6 to known transcriptional regulators and on the basis of the effects of mes mutations on transgene expression in the germline, the MES proteins are predicted to be transcriptional repressors. One of the MES proteins, MES-3, is a novel protein with no recognizable motifs. In this article we show that MES-3 is localized in the nuclei of embryos and germ cells, consistent with its predicted role in transcriptional regulation. Its distribution in the germline and in early embryos does not depend on the wild-type functions of the other MES proteins. However, its nuclear localization in midstage embryos and its persistence in the primordial germ cells depend on wild-type MES-2 and MES-6. These results are consistent with biochemical data showing that MES-2, MES-3, and MES-6 associate in a complex in embryos. The distribution of MES-3 in the adult germline is regulated by the translational repressor GLD-1: MES-3 is absent from the region of the germline where GLD-1 is known to be present, MES-3 is overexpressed in the germline of gld-1 mutants, and GLD-1 specifically binds the mes-3 3' untranslated region (3' UTR). Analysis of temperature-shifted mes-3(bn21ts) worms and embryos indicates that MES-3 function is required in the mother's germline and during embryogenesis to ensure subsequent normal germline development. We propose that MES-3 acts epigenetically to induce a germline state that is inherited through both meiosis and mitosis and that is essential for survival of the germline.

RNA-Regulated TRA-1 nuclear export controls sexual fate.

TRA-1, a member of the GLI family of transcription factors, is required for C. elegans female development. We find that TRA-1 has a sex-specific distribution consistent with its role in female development: nuclear TRA-1 is higher in hermaphrodite intestines and in specific germline regions than in males. TRA-1 patterns rely on nuclear export since treatment with leptomycin B, a CRM1-dependent export inhibitor, increases nuclearTRA-1 in males. TRA-1 export requires TRA-1 binding to the tra-2 3' untranslated region (3' UTR), as disruption of binding increases nuclear TRA-1 and female development. Our data are consistent with coexport of a TRA-1/tra-2 mRNA complex reducing TRA-1 nuclear activity, and identify an interesting RNA-based mechanism for controlling transcriptional activity and cell fate determination.

Induced senescence in HeLa cervical carcinoma cells containing elevated telomerase activity and extended telomeres.

Proliferation of normal somatic human cells in culture is limited by replicative senescence, a growth-arrested state that appears to be triggered by the erosion of telomeres. Tumor cells such as HeLa cervical carcinoma cells, which contain short telomeres, can be induced to undergo senescence by various manipulations including oncogene withdrawal. Repression of the human papillomavirus (HPV) type 18 E6/E7 genes in HeLa cells by the bovine papillomavirus E2 transcriptional regulatory protein results in reactivation of the dormant p53 and p105(Rb) tumor suppressor pathways in these cells, repression of telomerase, and profound growth arrest. Strikingly, the growth-arrested cells rapidly and synchronously acquired numerous characteristics of primary cells undergoing replicative senescence. To explore the role of telomerase and telomere length in induced senescence, we expressed an exogenous hTERT gene, which encodes the catalytic subunit of telomerase, to generate stable HeLa cell clones with elevated telomerase activity and extended telomeres. Expression of the E2 protein in these cells repressed HPV E6/E7 expression, activated tumor suppressor pathways, and induced senescence as assessed by growth arrest, morphological changes, senescence-associated beta-galactosidase expression, and increased autofluorescence. Cells carrying the hTERT gene and control cells displayed identical responses to E2 expression. Therefore, HeLa cell senescence induced by HPV repression is not triggered by short telomeres or low levels of telomerase activity.

Strand-specific postreplicative processing of mammalian telomeres.

Telomeres are specialized nucleoprotein structures that stabilize the ends of linear eukaryotic chromosomes. In mammalian cells, abrogation of telomeric repeat binding factor TRF2 or DNA-dependent protein kinase (DNA-PK) activity causes end-to-end chromosomal fusion, thus establishing an essential role for these proteins in telomere function. Here we show that TRF2-mediated end-capping occurs after telomere replication. The postreplicative requirement for TRF2 and DNA-PKcs, the catalytic subunit of DNA-PK, is confined to only half of the telomeres, namely, those that were produced by leading-strand DNA synthesis. These results demonstrate a crucial difference in postreplicative processing of telomeres that is linked to their mode of replication.

Translational repression: not just a Puf of smoke.

Proteins containing Puf domains interact with cofactors to form complexes that bind RNAs and control diverse developmental events. Recent studies have shed light on how the Puf family of proteins regulates mRNA activity.

Repression of human papillomavirus oncogenes in HeLa cervical carcinoma cells causes the orderly reactivation of dormant tumor suppressor pathways.

Most cervical carcinomas express high-risk human papillomaviruses (HPVs) E6 and E7 proteins, which neutralize cellular tumor suppressor function. To determine the consequences of removing the E6 and E7 proteins from cervical cancer cells, we infected HeLa cells, a cervical carcinoma cell line that contains HPV18 DNA, with a recombinant virus that expresses the bovine papillomavirus E2 protein. Expression of the E2 protein resulted in rapid repression of HPV E6 and E7 expression, followed approximately 12 h later by profound inhibition of cellular DNA synthesis. Shortly after E6/E7 repression, there was dramatic posttranscriptional induction of p53. Two p53-responsive genes, mdm2 and p21, were induced with slightly slower kinetics than p53 and appeared to be functional, as assessed by inhibition of cyclin-dependent kinase activity and p53 destabilization. There was also dramatic posttranscriptional induction of p105(Rb) and p107 after E6/E7 repression, followed shortly thereafter by induction of p130. By 24 h after infection, only hypophosphorylated p105(Rb) was detectable and transcription of several Rb/E2F-regulated genes was dramatically repressed. Constitutive expression of the HPV16 E6/E7 genes alleviated E2-induced growth inhibition and impaired activation of the Rb pathway and repression of E2F-responsive genes. This dynamic response strongly suggests that the p53 and Rb tumor suppressor pathways are intact in HeLa cells and that repression of HPV E6 and E7 mobilizes these pathways in an orderly fashion to deliver growth inhibitory signals to the cells. Strikingly, the major alterations in the cell cycle machinery underlying cervical carcinogenesis can be reversed by repression of the endogenous HPV oncogenes.