Contribution of Genetic Background to the Radiation Risk for Cancer and Non-Cancer Diseases in Ptch1+/- Mice.

Experimental mouse studies are important to gain a comprehensive, quantitative and mechanistic understanding of the biological factors that modify individual risk of radiation-induced health effects, including age at exposure, dose, dose rate, organ/tissue specificity and genetic factors. In this study, neonatal Ptch1+/- mice bred on CD1 and C57Bl/6 background received whole-body irradiation at postnatal day 2. This time point represents a critical phase in the development of the eye lens, cerebellum and dentate gyrus (DG), when they are also particularly susceptible to radiation effects. Irradiation was performed with γ rays (60Co) at doses of 0.5, 1 and 2 Gy, delivered at 0.3 Gy/min or 0.063 Gy/min. Wild-type and mutant mice were monitored for survival, lens opacity, medulloblastoma (MB) and neurogenesis defects. We identified an inverse genetic background-driven relationship between the radiosensitivity to induction of lens opacity and MB and that to neurogenesis deficit in Ptch1+/- mutants. In fact, high incidence of radiation-induced cataract and MB were observed in Ptch1+/-/CD1 mutants that instead showed no consequence of radiation exposure on neurogenesis. On the contrary, no induction of radiogenic cataract and MB was reported in Ptch1+/-/C57Bl/6 mice that were instead susceptible to induction of neurogenesis defects. Compared to Ptch1+/-/CD1, the cerebellum of Ptch1+/-/C57Bl/6 mice showed increased radiosensitivity to apoptosis, suggesting that differences in processing radiation-induced DNA damage may underlie the opposite strain-related radiosensitivity to cancer and non-cancer pathologies. Altogether, our results showed lack of dose-rate-related effects and marked influence of genetic background on the radiosensitivity of Ptch1+/-mice, supporting a major contribution of individual sensitivity to radiation risk in the population.

miRNA-Signature of Irradiated Ptch1+/- Mouse Lens is Dependent on Genetic Background.

One harmful long-term effect of ionizing radiation is cataract development. Recent studies have been focused on elucidating the mechanistic pathways involved in this pathogenesis. Since accumulating evidence has established a role of microRNAs in ocular diseases, including cataract, the goal of this work was to determine the microRNA signature of the mouse lens, at short time periods postirradiation, to understand the mechanisms related to radio-induced cataractogenesis. To evaluate the differences in the microRNA profiles, 10-week-old Patched1 heterozygous (Ptch1+/-) mice, bred onto two different genetic backgrounds (CD1 and C57Bl/6J), received whole-body 2 Gy γ-ray irradiation, and 24 h later lenses were collected. Next-generation sequencing and bioinformatics analysis revealed that genetic background markedly influenced the list of the deregulated microRNAs and the mainly predicted perturbed biological functions of 2 Gy irradiated Ptch1+/- mouse lenses. We identified a subset of microRNAs with a contra-regulated expression between strains, with a key role in regulating Toll-like receptor (TLR)-signaling pathways. Furthermore, a detailed analysis of miRNome data showed a completely different DNA damage response in mouse lenses 24 h postirradiation, mainly mediated by a marked upregulation of p53 signaling in Ptch1+/-/C57Bl/6J lenses that was not detected on a CD1 background. We propose a strict interplay between p53 and TLR signaling in Ptch1+/-/C57Bl/6J lenses shortly after irradiation that could explain both the resistance of this strain to developing lens opacities and the susceptibility of CD1 background to radiation-induced cataractogenesis through activation of epithelial-mesenchymal transition.

Cancer risk from low dose radiation in Ptch1+/- mice with inactive DNA repair systems: Therapeutic implications for medulloblastoma.

DSBs are harmful lesions produced through endogenous metabolism or by exogenous agents such as ionizing radiation, that can trigger genomic rearrangements. We have recently shown that exposure to 2 Gy of X-rays has opposite effects on the induction of Shh-dependent MB in NHEJ- and HR-deficient Ptch1+/- mice. In the current study we provide a comprehensive link on the role of HR/NHEJ at low doses (0.042 and 0.25 Gy) from the early molecular changes through DNA damage processing, up to the late consequences of their inactivation on tumorigenesis. Our data indicate a prominent role for HR in genome stability, by preventing spontaneous and radiation-induced oncogenic damage in neural precursors of the cerebellum, the cell of origin of MB. Instead, loss of DNA-PKcs function increased DSBs and apoptosis in neural precursors of the developing cerebellum, leading to killing of tumor initiating cells, and suppression of MB tumorigenesis in DNA-PKcs-/-/Ptch1+/- mice. Pathway analysis demonstrates that DNA-PKcs genetic inactivation confers a remarkable radiation hypersensitivity, as even extremely low radiation doses may deregulate many DDR genes, also triggering p53 pathway activation and cell cycle arrest. Finally, by showing that DNA-PKcs inhibition by NU7441 radiosensitizes human MB cells, our in vitro findings suggest the inclusion of MB in the list of tumors beneficiating from the combination of radiotherapy and DNA-PKcs targeting, holding promise for clinical translation.

BIOINFORMATIC ANALYSIS OF DOSE- AND TIME-DEPENDENT miRNome RESPONSES.

The advent of new 'omics' techniques determined a massive boost in the measurement of the whole spectra of molecules within cells, favoring promising new radiobiological studies at low doses. The main aim of this work was to assess the radiation-induced perturbations of miRNA profiles and their temporal dynamics. Human Umbilical Vein Endothelial Cells were irradiated with low doses of γ-rays. At different time points post-irradiation, cells were harvested and miRNAs isolated. A full mapping of the miRNA sequences via Next-Generation-Sequencing analysis was performed followed by bioinformatic analyses. Pathway enrichment analyses on the differentially expressed miRNAs focused both on the averaged effects of different doses over the 24-h experiment and on the altered temporal dynamics of the miRNA profiles. These complementary analyses provided a picture of the dose- and time-dependent miRNAs responses, allowing to better explore the candidate biomarkers linked to radiation exposures and their corresponding pathways and functions.

Alcohol consumption and site-specific cancer risk: a comprehensive dose-response meta-analysis.

BACKGROUND: Alcohol is a risk factor for cancer of the oral cavity, pharynx, oesophagus, colorectum, liver, larynx and female breast, whereas its impact on other cancers remains controversial. METHODS: We investigated the effect of alcohol on 23 cancer types through a meta-analytic approach. We used dose-response meta-regression models and investigated potential sources of heterogeneity. RESULTS: A total of 572 studies, including 486 538 cancer cases, were identified. Relative risks (RRs) for heavy drinkers compared with nondrinkers and occasional drinkers were 5.13 for oral and pharyngeal cancer, 4.95 for oesophageal squamous cell carcinoma, 1.44 for colorectal, 2.65 for laryngeal and 1.61 for breast cancer; for those neoplasms there was a clear dose-risk relationship. Heavy drinkers also had a significantly higher risk of cancer of the stomach (RR 1.21), liver (2.07), gallbladder (2.64), pancreas (1.19) and lung (1.15). There was indication of a positive association between alcohol consumption and risk of melanoma and prostate cancer. Alcohol consumption and risk of Hodgkin's and Non-Hodgkin's lymphomas were inversely associated. CONCLUSIONS: Alcohol increases risk of cancer of oral cavity and pharynx, oesophagus, colorectum, liver, larynx and female breast. There is accumulating evidence that alcohol drinking is associated with some other cancers such as pancreas and prostate cancer and melanoma.

Alcohol drinking and cutaneous melanoma risk: a systematic review and dose-risk meta-analysis.

It has been suggested that alcohol intake increases sunburn severity, a major risk factor for cutaneous melanoma (CM). Several epidemiological studies have investigated the relationship between alcohol consumption and CM, but the evidence is inconsistent. Therefore, we aimed to quantify this relationship better, using a meta-analytical approach. The dose-risk relationship was also modelled through a class of flexible nonlinear meta-regression random effects models. The present meta-analysis included 16 studies (14 case-control and two cohort investigations) with a total of 6251 cases of CM. The pooled relative risk (RR) for any alcohol drinking compared with no/occasional drinking was 1·20 [95% confidence interval (CI) 1·06-1·37]. The risk estimate was similar in case-control (RR 1·20, 95% CI 1·01-1·44) and cohort studies (RR 1·26, 95% CI 1·19-1·35). The pooled RR was 1·10 (95% CI 0·96-1·26) for light alcohol drinking (≤ 1 drink per day) and 1·18 (95% CI 1·01-1·40) for moderate-to-heavy drinking. The pooled RR from 10 studies adjusting for sun exposure was 1·15 (95% CI 0·94-1·41), while the RR from six unadjusted studies was 1·27 (95% CI 1·20-1·35). No evidence of publication bias was detected. This meta-analysis of published data reveals that alcohol consumption is positively associated with the risk of CM. However, caution in interpreting these results is required, as residual confounding by sun exposure cannot be ruled out.

Light alcohol drinking and cancer: a meta-analysis.

BACKGROUND: There is convincing evidence that alcohol consumption increases the risk of cancer of the colorectum, breast, larynx, liver, esophagus, oral cavity and pharynx. Most of the data derive from studies that focused on the effect of moderate/high alcohol intakes, while little is known about light alcohol drinking (up to 1 drink/day). PATIENTS AND METHODS: We evaluated the association between light drinking and cancer of the colorectum, breast, larynx, liver, esophagus, oral cavity and pharynx, through a meta-analytic approach. We searched epidemiological studies using PubMed, ISI Web of Science and EMBASE, published before December 2010. RESULTS: We included 222 articles comprising ∼92 000 light drinkers and 60 000 non-drinkers with cancer. Light drinking was associated with the risk of oropharyngeal cancer [relative risk, RR = 1.17; 95% confidence interval (CI) 1.06-1.29], esophageal squamous cell carcinoma (SCC) (RR = 1.30; 95% CI 1.09-1.56) and female breast cancer (RR = 1.05; 95% CI 1.02-1.08). We estimated that ∼5000 deaths from oropharyngeal cancer, 24 000 from esophageal SCC and 5000 from breast cancer were attributable to light drinking in 2004 worldwide. No association was found for colorectum, liver and larynx tumors. CONCLUSIONS: Light drinking increases the risk of cancer of oral cavity and pharynx, esophagus and female breast.

The radiation bystander effect and its potential implications for human health.

A long-held dogma in radiation biology has been that the biological effects of exposure to ionizing radiation occur as a result of damage in directly irradiated cells and that no effect would occur in neighboring unirradiated cells. This paradigm has been frequently challenged by reports of radiation effects in unirradiated or 'bystander' cells receiving signals from directly irradiated cells, an issue that may have substantial impact on radiation risk assessment and development of radiation-based therapies. Radiation-induced bystander effects have been shown in single-cell systems in vitro for an array of cancer relevant endpoints, and may trigger damage in more complex 3-D tissue systems. They may be mediated by soluble factors released by irradiated cells into the extracellular environment and/or by the passage of mediator molecules through gap-junction intercellular communication. To date, evidence that radiation-associated bystander or abscopal responses are effectual in vivo has been limited, but new data suggest that they may significantly affect tumor development in susceptible mouse models. Further understanding of how the signal/s is transmitted to unirradiated cells and tissues and how it provokes long-range and significant responses is crucial. By summarizing the existing evidence of radiation induced bystander-like effects in various systems with emphasis on in vivo findings, we will discuss the potential mechanisms involved in these observations and how effects in bystander cells contribute to uncertainties in assessing cancer risks associated with radiation exposure.

Alcohol drinking and risk of renal cell carcinoma: results of a meta-analysis.

BACKGROUND: The role of alcohol consumption in relation with renal cell carcinoma is still unclear; a few studies have reported a beneficial effect of moderate levels of alcohol consumption, whereas it remains still under debate whether there is a dose-response association. MATERIALS AND METHODS: Twenty observational studies (4 cohort, 1 pooled and 15 case-control) reporting results on at least three levels of alcohol consumption were selected through a combined search with PubMed and EMBASE of articles published before November 2010. Overall relative risks (RRs) and 95% confidence intervals (CIs) were estimated using random-effects models, and both second-order fractional polynomials and random effect meta-regression models were implemented for the study of dose-risk relation. RESULTS: The estimated RRs were 0.85 (95% CI: 0.80-0.92) for any alcohol drinking, 0.90 (95% CI: 0.83-0.97) for light drinking (0.01-12.49 g/day), 0.79 (95% CI: 0.71-0.88) for moderate drinking (12.5-49.9 g/day) and 0.89 (95% CI: 0.58-1.39) for heavy drinking (≥50 g/day), respectively. CONCLUSION: Our meta-analysis supports the hypothesis of a negative effect of moderate alcohol consumption on the risk of renal cell cancer.

Role of connexin43 and ATP in long-range bystander radiation damage and oncogenesis in vivo.

Ionizing radiation is a genotoxic agent and human carcinogen. Recent work has questioned long-held dogmas by showing that cancer-associated genetic alterations occur in cells and tissues not directly exposed to radiation, questioning the robustness of the current system of radiation risk assessment. In vitro, diverse mechanisms involving secreted soluble factors, gap junction intercellular communication (GJIC) and oxidative metabolism are proposed to mediate these indirect effects. In vivo, the mechanisms behind long-range 'bystander' responses remain largely unknown. Here, we investigate the role of GJIC in propagating radiation stress signals in vivo, and in mediating radiation-associated bystander tumorigenesis in mouse central nervous system using a mouse model in which intercellular communication is downregulated by targeted deletion of the connexin43 (Cx43) gene. We show that GJIC is critical for transmission of oncogenic radiation damage to the non-targeted cerebellum, and that a mechanism involving adenosine triphosphate release and upregulation of Cx43, the major GJIC constituent, regulates transduction of oncogenic damage to unirradiated tissues in vivo. Our data provide a novel hypothesis for transduction of distant bystander effects and suggest that the highly branched nervous system, similar to the vascular network, has an important role.

Opposite modifying effects of HR and NHEJ deficiency on cancer risk in Ptc1 heterozygous mouse cerebellum.

Heterozygous Patched1 (Ptc1(+/-)) mice are prone to medulloblastoma (MB), and exposure of newborn mice to ionizing radiation dramatically increases the frequency and shortens the latency of MB. In Ptc1(+/-) mice, MB is characterized by loss of the normal remaining Ptc1 allele, suggesting that genome rearrangements may be key events in MB development. Recent evidence indicates that brain tumors may be linked to defects in DNA-damage repair processes, as various combinations of targeted deletions in genes controlling cell-cycle checkpoints, apoptosis and DNA repair result in MB in mice. Non-homologous end joining (NHEJ) and homologous recombination (HR) contribute to genome stability, and deficiencies in either pathway predispose to genome rearrangements. To test the role of defective HR or NHEJ in tumorigenesis, control and irradiated Ptc1(+/-) mice with two, one or no functional Rad54 or DNA-protein kinase catalytic subunit (DNA-PKcs) alleles were monitored for MB development. We also examined the effect of Rad54 or DNA-PKcs deletion on the processing of endogenous and radiation-induced double-strand breaks (DSBs) in neural precursors of the developing cerebellum, the cells of origin of MB. We found that, although HR and NHEJ collaborate in protecting cells from DNA damage and apoptosis, they have opposite roles in MB tumorigenesis. In fact, although Rad54 deficiency increased both spontaneous and radiation-induced MB development, DNA-PKcs disruption suppressed MB tumorigenesis. Together, our data provide the first evidence that Rad54-mediated HR in vivo is important for suppressing tumorigenesis by maintaining genomic stability.

Modulation of basal and squamous cell carcinoma by endogenous estrogen in mouse models of skin cancer.

Patched1 heterozygous mice (Ptch1(+/-)) are useful for basal cell carcinoma (BCC) studies, being remarkably susceptible to BCC induction by ultraviolet or ionizing radiation. Analogously, skin carcinogenesis-susceptible (Car-S) mice are elective for studies of papilloma and squamous cell carcinoma (SCC) induction. We previously reported a striking effect of gender on BCC induction in Ptch1(+/-) mice, with total resistance of females; likewise, Car-S females show increased skin tumor resistance relative to males. Here, we investigated the protective role of endogenous estrogen in skin keratinocyte tumorigenesis. Control (CN) and ovariectomized Ptch1(+/-) or Car-S females were irradiated for BCC induction or topically treated with chemical carcinogens for SCC induction. Susceptibility to BCC or SCC was dramatically increased in ovariectomized Ptch1(+/-) and Car-S females and restored to levels observed in males. Remarkably, progression of initially benign papillomas to malignant SCC occurred only in ovariectomized Car-S females. We explored the mechanisms underlying tumor progression and report overexpression of estrogen receptor (ER)-alpha, downregulation of ERbeta and upregulation of cyclin D1 in papillomas from ovariectomized Car-S relative to papillomas from CN females. Thus, an imbalanced ERalpha/ERbeta expression may be associated with estrogen-mediated modulation of non-melanoma skin carcinogenesis, with a key role played by cyclin D1. Our findings underscore a highly protective role of endogenous estrogen against skin tumorigenesis by diverse agents in two independent mouse models of skin cancer.

Insulin resistance and low urinary citrate excretion in calcium stone formers.

Epidemiological data suggest an association between kidney stones and some features of metabolic syndrome such as an overweight condition, arterial hypertension or glucose intolerance. However, mechanisms remain to be elucidated. This study aimed to evaluate insulin resistance, as assessed by homeostasis model assessment (HOMA-IR), and urine composition analysis in patients affected by calcium nephrolithiasis. A cohort of 61 (38 male, 29-57 years of age) non-diabetic calcium stone formers was studied. Data about body mass index, arterial blood pressure, serum biochemistry including parathyroid hormone and calcitriol were recorded in all the patients; fasting glucose and insulin were determined to calculate HOMA-IR value and accordingly the patients were grouped into tertiles. Urine pH and urinary excretion of calcium, citrate, phosphate, oxalate, uric acid, urea and creatinine were measured on 24h urine samples. Patients of the highest HOMA-IR tertile showed lower urine citrate levels than patients of the lowest HOMA-IR tertile (475+/-243 vs. 630+/-187 mg/24h, p<0.05), whereas no difference was detected as far as urinary oxalate, calcium, uric acid, phosphate, and urine pH and urine volume output were concerned. HOMA-IR values were positively related to uric acid serum levels (r=0.31, p<0.05) and negatively to urinary citrate excretion (r=-0.26, p<0.05). Hypocitraturic patients showed higher levels of HOMA-IR than normocitraturic ones (3.03+/-0.92 vs. 2.25+/-1.19, p<0.05). This study shows that a higher level of insulin resistance is associated with lower urinary citrate excretion, and that hypocitraturic patients show a greater insulin resistance than normocitraturic calcium stone formers. This may be related to changes in citrate, Na(+)-K(+) and H(+) renal tubule transports, which have been described in insulin resistance. In conclusion, insulin resistance may contribute to an increased risk of calcium stone formation by lowering urinary citrate excretion. This finding suggests the need for a careful metabolic assessment in patients known to form calcium stones in order to ensure stone recurrence prevention and cardiovascular protection.

Two-hit model for progression of medulloblastoma preneoplasia in Patched heterozygous mice.

Inactivation of one Ptc1 allele predisposes humans and mice to spontaneous medulloblastoma development, and irradiation of newborn Ptc1 heterozygous mice results in dramatic increase of medulloblastoma incidence. While a role for loss of wild-type (wt) Ptc1 (LOH) in radiation-induced medulloblastomas from Ptc1(neo67/+) mice is well established, the importance of this event in spontaneous medulloblastomas is still unclear. Here, we demonstrate that biallelic Ptc1 loss plays a crucial role in spontaneous medulloblastomas, as shown by high rate of wt Ptc1 loss in spontaneous tumors. In addition, remarkable differences in chromosomal events involving the Ptc1 locus in spontaneous and radiation-induced medulloblastomas suggest distinct mechanisms for Ptc1 loss. To assess when, during tumorigenesis, Ptc1 loss occurs, we characterized cerebellar abnormalities that precede tumor appearance in Ptc1(neo67/+) mice. We show that inactivation of only one copy of Ptc1 is sufficient to give rise to abnormal cerebellar proliferations with different degree of altered cell morphology, but lacking potential to progress to neoplasia. Furthermore, we identify biallelic Ptc1 loss as the event causally related to the transition from the preneoplastic stage to full blown medulloblastoma. These results underscore the utility of the Ptc1(neo67/+) mouse model for studies on the mechanisms of medulloblastoma and for development of new therapeutic strategies.

Three dimensional (3D) analysis of the morphological changes induced by 50 Hz magnetic field exposure on human lymphoblastoid cells (Raji).

Human Raji B lymphoid cells after exposure for 64 h to a 1 mT (rms) 50 Hz sinusoidal magnetic field showed a reorganization of membrane and cytoskeletal components. Atomic force microscopy in air revealed several modifications in 80% of the exposed cells, such as loss of microvilli-like structures followed by progressive appearance of membrane introflections. This change in plasma membrane morphology was also accompanied by a different actin distribution, as detected by phalloidin fluorescence. These observations support our previous hypothesis that electric and magnetic fields may modify the plasma membrane structure.

The impact of premature menopause on women's experience of self.

Surgically or chemically induced premature menopause may have an impact on women's sense of self: the physical, psychological, social, and spiritual sense of self. This ethnographic research study explores the major factors that assaulted prematurely menopausal women's concept of self and the ways in which they attempted to readjust that concept. A unifying domain, evolution of self, and three constitutive themes emerged: change/loss, connectedness/disconnectedness, and transcendence/transformation. A holistic nurse-client relationship that transcends the hospital experience and extends into the community may help prematurely menopausal women to move toward a more synthesized sense of self and a greater degree of self-actualization.

Effect of extremely low frequency (ELF) magnetic field exposure on morphological and biophysical properties of human lymphoid cell line (Raji).

Human B lymphoid cells (Raji) were exposed for 72 h to a 50 Hz sinusoidal magnetic field at a density of 2 milliTesla (rms). The results of exposure showed a decrease in membrane fluidity as detected by Laurdan emission spectroscopy and DPH fluorescence polarization. Field exposure also resulted in a reorganization of cytoskeletal components. Scanning electron microscopy (SEM) revealed a loss of microvilli in the exposed cells. This change in plasma membrane morphology was accompanied by a different actin distribution, as detected by phalloidin fluorescence. We also present evidence that EMF exposure of Raji cells can interfere with protein phosphorylation. Our observations confirm the hypothesis that electric and magnetic fields may modify the plasma membrane structure and interfere with the initiation of the signal cascade pathways.

Exposure to a 50 Hz electromagnetic field induces activation of the Epstein-Barr virus genome in latently infected human lymphoid cells.

The EBV genome in latently infected lymphoid cells offers an opportunity to follow effects on the transcriptional and translational product clearly distinguishable from those of the host cell genome. Exposure of Akata cells, a human lymphoid cell line latently infected by the EBV genome, to a 50 Hz EMF resulted in an increased number of cells expressing the virus early antigens. This finding provides additional evidence that DNA can be modulated by a magnetic field.

Cell-cycle kinetics of Friend erythroleukemia cells in a magnetically shielded room and in a low-frequency/low-intensity magnetic field.

This work was undertaken to compare the behavior of Friend erythroleukemia cells in a solenoid, where the magnetic field was 70 microT at 50 Hz (plus 45 microT DC of Earth) with that of the same cells in a magnetically shielded room, where the magnetic field was attenuated to 20 nT DC and 2.5 pT AC. The control laboratory magnetic field corresponded to 45 microT DC and a stray 50 Hz field below 0.2 microT. The culture growth cycle of cells maintained inside the solenoid was slightly accelerated compared with that of cells maintained outside the solenoid (P < .05). This stimulation probably depended on sensitivity of cell cycle to a magnetic field, because, inside the solenoid, the percentage of G1 cells slightly increased during the culture growth cycle, whereas that of S cells slightly decreased. Acceleration of growth was detected soon after exposure of the cultures to the solenoid field, and growth did not change further if the action of this field continued for a long time, accounting for adaptation. The solenoid field also caused a small increase of cell survival without influencing cell volume. By contrast, the culture growth cycle of cells maintained inside the magnetically shielded room was slightly decelerated compared with that of cells maintained outside the room (P < .05). The essential absence of any field inside the magnetically shielded room also caused a small increase of cell volume, whereas, during the culture growth cycle, the percentage of G1 cells decreased, and that of S cells increased. The majority of these events did not change in cells induced to differentiate hemoglobin through dimethylsulfoxide.

Scanning eye movements made when viewing film: preliminary observations.

Eye movements were recorded in 10 adult subjects during the viewing of fiction and nonfiction films. Individual differences in scan paths for fiction films were found to be relatively small. Generally, eyes concentrated on the screen center when looking at characters and objects in rapid motion. Scan paths through the screen were observed in special cases, for example, in the case of a dialogue between two characters. No differences emerged in scan paths for the same clip presented in black-and-white and color versions. Results are relevant for both filmmaking and research on perceptual and cognitive strategies involved in processing motion pictures.