[Sleep disorders in patients with a neurocognitive disorder]. / Les troubles du sommeil chez les patients atteints d'un trouble neurocognitif.

INTRODUCTION: Sleep disorders are prevalent in patients with a neurocognitive disorder, and diagnosis and treatment in these patients remain challenging in clinical practice. METHODS: This narrative review offers a systematic approach to diagnose and treat sleep disorders in neurocognitive disorders. RESULTS: Alzheimer's disease is often associated with circadian rhythm disorders, chronic insomnia, and sleep apnea-hypopnea syndrome. Alpha-synucleinopathies (e.g., Parkinson's disease and Lewy body dementia) are often associated with a rapid eye movement sleep behavior disorder, restless legs syndrome, chronic insomnia, and sleep apnea-hypopnea syndrome. A focused history allows to diagnose most sleep disorders. Clinicians should ensure to gather the following information in all patients with a neurocognitive disorder: (1) the presence of difficulties falling asleep or staying asleep, (2) the impact of sleep disturbances on daily functioning (fatigue, sleepiness and other daytime consequences), and (3) abnormal movements in sleep. Sleep diaries and questionnaires can assist clinicians in screening for specific sleep disorders. Polysomnography is recommended if a rapid eye movement sleep behavior disorder or a sleep apnea-hypopnea syndrome are suspected. Sleep complaints should prompt clinicians to ensure that comorbidities interfering with sleep are properly managed. The main treatment for moderate to severe obstructive sleep apnea-hypopnea syndrome remains continuous positive airway pressure, as its efficacy has been demonstrated in patients with neurocognitive disorders. Medications should also be reviewed, and time of administration should be optimized (diuretics and stimulating medications in the morning, sedating medications in the evening). Importantly, cholinesterase inhibitors (especially donepezil) may trigger insomnia. Switching to morning dosing or to an alternative drug may help. Cognitive-behavioral therapy for insomnia is indicated to treat chronic insomnia in neurocognitive disorders. False beliefs regarding sleep should be addressed with the patient and their caregiver. The sleep environment should be optimized (decrease light exposure at night, minimize noise, avoid taking vital signs, etc.). Sleep restriction can be considered as patients with a neurocognitive disorder often spend too much time in bed. The need for naps should be assessed case by case as naps may contribute to insomnia in some patients but allow others to complete their diurnal activities. Trazodone (50mg) may also be used under certain circumstances in chronic insomnia. Recent evidence does not support a role for exogenous melatonin in patients with a neucognitive disorder and insomnia. Patients in long-term care facilities are often deprived of an adequate diurnal exposure to light. Increasing daytime exposure to light may improve sleep and mood. Patients with circadian rhythm disorders can also benefit from light therapy (morning bright light therapy in case of phase delay and evening bright light therapy in case of phase advance). Rapid eye movement sleep behavior disorder can lead to violent behaviors, and the sleeping environment should be secured (e.g., mattress on the floor, remove surrounding objects). Medication exacerbating this disorder should be stopped if possible. High dose melatonin (6 to 18mg) or low dose clonazepam (0.125-0.25mg) at bedtime may be used to reduce symptoms. Melatonin is preferred in first-line as it is generally well tolerated with few side effects. Patients with restless legs syndrome should be investigated for iron deficiency. Medication decreasing dopaminergic activity should be reduced or stopped if possible. Behavioral strategies such as exercise and leg massages may be beneficial. Low-dose dopamine agonists (such as pramipexole 0.125mg two hours before bedtime) can be used to treat the condition, but a prolonged treatment may paradoxically worsen the symptoms. Alpha-2-delta calcium channel ligands can also be used while monitoring for the risk of falls. CONCLUSION: Multiple and sustained nonpharmacological approaches are recommended for the treatment of sleep disturbances in patients with neurocognitive disorder. Pharmacological indications remain limited, and further randomized clinical trials integrating a multimodal approach are warranted to evaluate the treatment of sleep disorders in specific neurocognitive disorders.

Comparative effectiveness and safety of antipsychotic drugs in schizophrenia treatment: a real-world observational study.

OBJECTIVE: The objective was to compare, in a real-world setting, the risk of mental and physical health events associated with different antipsychotic drugs (clozapine, olanzapine, risperidone, quetiapine and first-generation antipsychotics) in patients with SZ. METHODS: This is a retrospective cohort study using administrative data. Outcome measures included any mental health event (suicide, hospitalization or emergency visit for mental disorders) and physical health event (death other than suicide, hospitalization or emergency visit for physical disorders). Cox proportional hazard models were used to estimate the hazard ratios of the events associated with the use of the different antipsychotic drugs. RESULTS: The cohort included 18 869 adult patients living in the province of Quebec (Canada) with SZ and starting antipsychotic drugs between January 1998 and December 2005. Results show that quetiapine and not using any antipsychotics were associated with an increased risk of mental and physical health events as compared to other drugs. The second finding is the confirmation of better performance of clozapine. The results were robust across sensitivity analyses. CONCLUSION: Both findings call for an international public health and drug agencies surveillance of 'real-world' antipsychotic medication to ensure the optimal choices in treatment guidelines for SZ.

Using fiducial markers in the prostate bed in postprostatectomy external beam radiation therapy improves accuracy over surgical clips.

BACKGROUND AND PURPOSE: The purpose of this work was to assess the stability of fiducial markers in the prostate bed and compared their use to surgical clips. PATIENTS AND METHODS: In this study, 3-4 gold fiducial markers were transrectally implanted in the prostate bed of 14 patients. The stability of the fiducial markers position (fiducial markers fixity) over an EBRT course was assessed. Furthermore, the advantages of the fiducial markers compared to the surgical clips were assessed and the interobserver variation between the two technologies was compared. RESULTS: The mean fiducial marker migration during a course of EBRT was small with 1.2 mm (SD ± 0.8 mm). Compared to fiducial markers, the matches with surgical clips were mismatched ≥ 2 mm in 68% of treatments. This discrepancy of > 2 mm was on average 3.7 ± 1.3 mm. There was less interobserver variability for matching of fiducial markers (0.8 ± 0.7 mm) than for surgical clips (2.0 ± 1.6 mm). CONCLUSION: Fiducial markers showed less interobserver variability in matching and less variation in position than surgical clips. Fiducial markers could ultimately help in reducing treatment margins.

High mechanical strength fiber Bragg gratings made with infrared femtosecond pulses and a phase mask.

We report that by using 800 nm femtosecond pulses and the phase-mask technique, first-order fiber Bragg gratings with refractive index modulation in excess of 1×10(-3) can be written through both the acrylate and polyimide coatings of unloaded standard silica fibers without noticeable degradation of mechanical strength. We also demonstrate that the same experimental conditions can be applied for efficient FBG writing through the polyimide coating of pure silica core fibers, opening significant opportunities in the field of fiber sensors.

Sleep regulation and sex hormones exposure in men and women across adulthood.

This review aims to discuss how endogenous and exogenous testosterone exposures in men and estrogens/progesterone exposures in women interact with sleep regulation. In young men, testosterone secretion peaks during sleep and is linked to sleep architecture. Animal and human studies support the notion that sleep loss suppresses testosterone secretion. Testosterone levels decline slowly throughout the aging process, but relatively few studies investigate its impact on age-related sleep modifications. Results suggest that poorer sleep quality is associated with lower testosterone concentrations and that sleep loss may have a more prominent effect on testosterone levels in older individuals. In women, sex steroid levels are characterized by a marked monthly cycle and reproductive milestones such as pregnancy and menopause. Animal models indicate that estrogens and progesterone influence sleep. Most studies do not show any clear effects of the menstrual cycle on sleep, but sample sizes are too low, and research designs often inhibit definitive conclusions. The effects of hormonal contraceptives on sleep are currently unknown. Pregnancy and the postpartum period are associated with increased sleep disturbances, but their relation to the hormonal milieu still needs to be determined. Finally, studies suggest that menopausal transition and the hormonal changes associated with it are linked to lower subjective sleep quality, but results concerning objective sleep measures are less conclusive. More research is necessary to unravel the effects of vasomotor symptoms on sleep. Hormone therapy seems to induce positive effects on sleep, but key concerns are still unresolved, including the long-term effects and efficacy of different hormonal regimens.

EEG rhythmic and arrhythmic spectral components and functional connectivity at resting state may predict the development of synucleinopathies in idiopathic REM sleep behavior disorder.

STUDY OBJECTIVES: Idiopathic/isolated REM-sleep behavior disorder (iRBD) often precedes the onset of synucleinopathies. Here, we investigated whether baseline resting-state EEG advanced spectral power and functional connectivity differ between iRBD patients who converted towards a synucleinopathy at follow-up and those who did not. METHODS: Eighty-one participants with iRBD (66.89±6.91 years) underwent a baseline resting-state EEG recording, a neuropsychological assessment and a neurological examination. We estimated EEG power spectral density using standard analyses and derived spectral estimates of rhythmic and arrhythmic components. Global and pairwise EEG functional connectivity analyses were computed using the weighted phase-lag index (wPLI). Pixel-based permutation tests were used to compare groups. RESULTS: After a mean follow-up of 5.01±2.76 years, 34 patients were diagnosed with a synucleinopathy (67.81±7.34 years) and 47 remained disease-free (65.53±7.09 years). Among patients who converted, 22 were diagnosed with Parkinson's disease and 12 with dementia with Lewy bodies. As compared to patients who did not convert, patients who converted exhibited at baseline higher relative theta standard power, steeper slopes of the arrhythmic component and higher theta rhythmic power mostly in occipital regions. Furthermore, patients who converted showed higher beta global wPLI but lower alpha wPLI between left temporal and occipital regions. CONCLUSION: Analyses of resting-state EEG rhythmic and arrhythmic components and functional connectivity suggest an imbalanced excitatory-to-inhibitory activity within large-scale networks, which is associated with later development of a synucleinopathy in iRBD patients.

Graphene-based plasmonic switches at near infrared frequencies.

The concept, analysis, and design of series switches for graphene-strip plasmonic waveguides at near infrared frequencies are presented. Switching is achieved by using graphene's field effect to selectively enable or forbid propagation on a section of the graphene strip waveguide, thereby allowing good transmission or high isolation, respectively. The electromagnetic modeling of the proposed structure is performed using full-wave simulations and a transmission line model combined with a matrix-transfer approach, which takes into account the characteristics of the plasmons supported by the different graphene-strip waveguide sections of the device. The performance of the switch is evaluated versus different parameters of the structure, including surrounding dielectric media, electrostatic gating and waveguide dimensions.

Plane wave excitation-detection of non-resonant plasmons along finite-width graphene strips.

An approach to couple free-space waves and non-resonant plasmons propagating along graphene strips is proposed based on the periodic modulation of the graphene strip width. The solution is technologically very simple, scalable in frequency, and provides customized coupling angle and intensity. Moreover, the coupling properties can be dynamically controlled at a fixed frequency via the graphene electrical field effect, enabling advanced and flexible plasmon excitation-detection strategies. We combine a previously derived scaling law for graphene strips with leaky-wave theory borrowed from microwaves to achieve rigorous and efficient modeling and design of the structure. In particular we analytically derive its dispersion, predict its coupling efficiency and radiated field structure, and design strip configurations able to fulfill specific coupling requirements. The proposed approach and developed methods are essential to the recent and fundamental problem of the excitation-detection of non-resonant plasmons propagating along a continuous graphene strip, and could pave the way to smart all-graphene sensors and transceivers.

Focal HDR brachytherapy boost to stereotactic radiotherapy (fBTsRT) for prostate cancer: a phase II randomized controlled trial.

BACKGROUND: For patients with a higher burden of localized prostate cancer, radiation dose escalation with brachytherapy boosts have improved cancer control outcomes at the cost of urinary toxicity. We hypothesize that a focal approach to brachytherapy boosts targeting only grossly visualized tumor volumes (GTV) combined with stereotactic radiotherapy will improve quality of life (QoL) outcomes without compromising cancer control. METHODS: 150 patients with intermediate or high-risk prostate cancer will be enrolled and randomized 1:1 in a cohort multiple randomized clinical trial phase 2 design. Patients are eligible if planned for standard-of-care (SOC) high dose rate (HDR) brachytherapy boost to radiotherapy (RT) with GTVs encompassing < 50% of the prostate gland. Those randomly selected will be offered the experimental treatment, consisting of focal HDR brachytherapy boost (fBT) of 13-15 Gy in 1 fraction followed by stereotactic radiotherapy (sRT) 36.25-40 Gy in 5 fractions to the prostate (+/- 25 Gy to the elective pelvis) delivered every other day. The primary endpoint is to determine if fBTsRT is superior to SOC by having fewer patients experience a minimally important decline (MID) in urinary function as measured by EPIC-26 at 1 and 2 years. Secondary endpoints include rates of toxicity measured by Common Terminology Criteria for Adverse Events (CTCAE), and failure-free survival outcomes. DISCUSSION: This study will determine whether a novel approach for the treatment of localized prostate cancer, fBTsRT, improves QoL and merits further evaluation. Trial registration This trial was prospectively registered in ClinicalTrials.gov as NCT04100174 as a companion to registry NCT03378856 on September 24, 2019.

Monte Carlo study of LDR seed dosimetry with an application in a clinical brachytherapy breast implant.

A Monte Carlo (MC) study was carried out to evaluate the effects of the interseed attenuation and the tissue composition for two models of 125I low dose rate (LDR) brachytherapy seeds (Medi-Physics 6711, IBt InterSource) in a permanent breast implant. The effect of the tissue composition was investigated because the breast localization presents heterogeneities such as glandular and adipose tissue surrounded by air, lungs, and ribs. The absolute MC dose calculations were benchmarked by comparison to the absolute dose obtained from experimental results. Before modeling a clinical case of an implant in heterogeneous breast, the effects of the tissue composition and the interseed attenuation were studied in homogeneous phantoms. To investigate the tissue composition effect, the dose along the transverse axis of the two seed models were calculated and compared in different materials. For each seed model, three seeds sharing the same transverse axis were simulated to evaluate the interseed effect in water as a function of the distance from the seed. A clinical study of a permanent breast 125I implant for a single patient was carried out using four dose calculation techniques: (1) A TG-43 based calculation, (2) a full MC simulation with realistic tissues and seed models, (3) a MC simulation in water and modeled seeds, and (4) a MC simulation without modeling the seed geometry but with realistic tissues. In the latter, a phase space file corresponding to the particles emitted from the external surface of the seed is used at each seed location. The results were compared by calculating the relevant clinical metrics V85, V100, and V200 for this kind of treatment in the target. D90 and D50 were also determined to evaluate the differences in dose and compare the results to the studies published for permanent prostate seed implants in literature. The experimental results are in agreement with the MC absolute doses (within 5% for EBT Gafchromic film and within 7% for TLD-100). Important differences between the dose along the transverse axis of the seed in water and in adipose tissue are obtained (10% at 3.5 cm). The comparisons between the full MC and the TG-43 calculations show that there are no significant differences for V85 and V100. For V200, 8.4% difference is found coming mainly from the tissue composition effect. Larger differences (about 10.5% for the model 6711 seed and about 13% for the InterSource125) are determined for D90 and D50. These differences depend on the composition of the breast tissue modeled in the simulation. A variation in percentage by mass of the mammary gland and adipose tissue can cause important differences in the clinical dose metrics V200, D90, and D50. Even if the authors can conclude that clinically, the differences in V85, V100, and V200 are acceptable in comparison to the large variation in dose in the treated volume, this work demonstrates that the development of a MC treatment planning system for LDR brachytherapy will improve the dose determination in the treated region and consequently the dose-outcome relationship, especially for the skin toxicity.

Decrease of Johne's disease prevalence and incidence in six Minnesota, USA, dairy cattle herds on a long-term management program.

The objective of this prospective longitudinal field study was to describe changes in prevalence of seroconversion and fecal shedding and changes in incidence rate of seroconversion, fecal shedding and culling of milk cows for clinical signs of Johne's disease (JD) in six Minnesota (USA) herds participating to the JD Demonstration Herd Project (JDDHP) from 2000 to December 2005. Changes in prevalence and incidence rate were evaluated in light of the owner's compliance to the JDDHP using a risk assessment (RA) score. Adult cows were tested regularly using serum ELISA and bacterial fecal culture to evaluate progress made throughout the control program. Logistic regression was used to evaluate the association between the risk for a cow to test positive and the year on the program. After 5 years of follow-up, the proportion of cows that tested positive to serum ELISA and fecal culture (all positive cultures as well as moderate to heavy shedders only) decreased significantly from the first to the last year (8-3.1%, 10.4-5.6% and 3.1-1.5%, respectively). Cox proportional hazards regression was used to evaluate change of incidence rate across birth cohorts. Birth cohorts were defined by birth date of the animals with the reference cohort or oldest cohort being already 12-24 months of age at the onset of the long-term management program. All cohorts were censored at 45 months of age. Compared to cows from the reference cohort, cows from cohorts that could have benefitted from the JDDHP in their young age (less than 12 months of age at the start of the program or born later) were significantly less at risk of seroconversion and fecal shedding (hazard ratios for seroconversion, any fecal shedding and heavy shedding less than 0.63, 0.67 and 0.62, respectively). For the three herds achieving good management changes with a risk assessment score under 30 at their last year of the study, the cohorts that were born after the program was instituted did better than those born before the start of the program, implying that the program could have helped around birth as well for those herds. This study suggests that reduction of environmental contamination of heifers up to a year of age may have had some impact on the success of the program. The JDDHP appears more beneficial for herds achieving a better reduction of their RA score with a decrease risk for infection in very young calves.

Wavelength-dependent modulation of brain responses to a working memory task by daytime light exposure.

In addition to classical visual effects, light elicits nonvisual brain responses, which profoundly influence physiology and behavior. These effects are mediated in part by melanopsin-expressing light-sensitive ganglion cells that, in contrast to the classical photopic system that is maximally sensitive to green light (550 nm), is very sensitive to blue light (470-480 nm). At present, there is no evidence that blue light exposure is effective in modulating nonvisual brain activity related to complex cognitive tasks. Using functional magnetic resonance imaging, we show that, while participants perform an auditory working memory task, a short (18 min) daytime exposure to blue (470 nm) or green (550 nm) monochromatic light (3 x 10(13) photons/cm2/s) differentially modulates regional brain responses. Blue light typically enhanced brain responses or at least prevented the decline otherwise observed following green light exposure in frontal and parietal cortices implicated in working memory, and in the thalamus involved in the modulation of cognition by arousal. Our results imply that monochromatic light can affect cognitive functions almost instantaneously and suggest that these effects are mediated by a melanopsin-based photoreceptor system.

Endogenous pain modulation during the formalin test in estrogen receptor beta knockout mice.

The involvement of estrogen in pain has been investigated in many ways. However the specific role played by estrogen receptors remains elusive. Estrogen receptors alpha and beta mediate different physiological functions. For example, estrogen receptor beta is more closely related to non-reproductive effects than the alpha subtype is. To verify the involvement of estrogen receptor beta on acute and persistent pain as well as on endogenous pain inhibitory mechanisms, hotplate and formalin tests were carried out in wild type (WT) and estrogen receptor beta knockout (ERbeta KO) mice of both sexes. Ovariectomies followed by estrogen and progesterone replacement were performed in female groups to insure comparable sex hormone levels. We found that nociceptive responses are lower in ERbeta KO female than in WT female mice during the interphase and early tonic phase II of the formalin test but not during acute and late tonic phases. Moreover, behavioral and spinal (c-Fos) differences were only observed in females. ERbeta KO females had lower c-Fos expression in laminae I-II and IV-V of the spinal cord than WT females. These results suggest that estrogen, through its actions on ERbeta, dampens the efficacy of endogenous pain modulation mechanisms during the interphase and/or inflammation process in the early phase II, triggering an increase in spinal nociceptive neuronal activity. This confirms our previous observations that estrogen specifically influences nociceptive responses during the interphase of the formalin test and demonstrates a role for ERbeta on endogenous pain modulation systems.

The effect of gender on autonomic and respiratory responses during sleep among both young and middle-aged subjects.

BACKGROUND AND OBJECTIVES: Sleep affects the control of circulation and respiratory function. Gender and age are also known to have a profound impact on the neural control of circulation. We investigated whether gender affects sleep-related cardiovascular and respiratory responses and whether these vary according to healthy subjects being young or middle-aged. METHODS: We studied 32 subjects: 8 women and 8 men aged 20-30 years (young), and 8 women and 8 men aged 50-60 years (middle-aged). Young women were under oral contraceptive therapy and middle-aged women were postmenopausal and not receiving hormonal replacement therapy. One-night polysomnography was used to assess RR variability during non-rapid eye movement (NREM) (stage 2) and rapid eye movement (REM) sleep. Low-frequency (LF) and high-frequency (HF) components, in normalized units (LFnu and HFnu) and LF/HF ratio were calculated on five-minute segments selected across the night and averaged for each sleep stage. The respiration frequency in NREM and REM sleep was also measured. Interaction between gender, age and sleep on autonomic and respiration variables was assessed by 2 x 2 x 2 analysis of variance (ANOVA). RESULTS: Compared to men, women had a greater NREM-to-REM increment in LFnu (gender-by-state interaction, p<0.01), a greater decrement in HFnu (interaction, p<0.01) and a greater increment in LF/HF (interaction, p<0.05). Women also showed a more pronounced increase in respiratory frequency during REM sleep compared to men in both groups of age (gender-by-state interaction, F=7.1, p<0.05). No gender-by-age-by-state interaction was observed to affect autonomic and respiration variables. CONCLUSION: NREM-to-REM excitatory cardiac and respiratory responses are more marked among women compared to men, regardless of their hormonal status and whether they are young or middle-aged.

Molecular genetics of ulcerative colitis-associated colon cancer in the interleukin 2- and beta(2)-microglobulin-deficient mouse.

Mice deficient in beta(2)-microglobulin and interleukin 2 (beta(2)m(null) x IL-2(null)) spontaneously develop colon cancer in the setting of chronic ulcerative colitis (UC). We investigated mutations of the Apc and p53 genes and microsatellite instability in colonic adenocarcinomas arising in this model. Mutations of the Apc and p53 genes in the regions corresponding to mutation hot spots in human colorectal cancer were determined by sequencing in 11 colonic adenocarcinomas. Microsatellite instability was determined in matched normal and neoplastic DNA at five loci. All 11 adenocarcinomas harbored Apc mutations. Of these 11 tumors, 5 harbored truncating mutations. A total of 67 Apc mutations were found in these 11 tumors; 59 were missense mutations, whereas 8 were frameshift or nonsense mutations. Six of the 11 adenocarcinomas harbored p53 mutations. A total of seven p53 mutations were found in these 11 tumors; all mutations were transitions, 4 of which were C:G-->T:A transitions occurring in codon 229 at cytosine-guanine dinucleotides. Nine adenocarcinomas exhibited microsatellite instability in at least one of the five loci examined; 1 tumor had microsatellite instability in two loci. Molecular genetics, as well as clinical features, of colon cancer in the beta(2)m(null) x IL-2(null) mice are similar to those of human UC-associated colorectal cancer. As such, this model appears to be an excellent animal model to study UC-associated colorectal carcinogenesis.

Light-sensitive brain pathways and aging.

Notwithstanding its effects on the classical visual system allowing image formation, light acts upon several non-image-forming (NIF) functions including body temperature, hormonal secretions, sleep-wake cycle, alertness, and cognitive performance. Studies have shown that NIF functions are maximally sensitive to blue wavelengths (460-480 nm), in comparison to longer light wavelengths. Higher blue light sensitivity has been reported for melatonin suppression, pupillary constriction, vigilance, and performance improvement but also for modulation of cognitive brain functions. Studies investigating acute stimulating effects of light on brain activity during the execution of cognitive tasks have suggested that brain activations progress from subcortical regions involved in alertness, such as the thalamus, the hypothalamus, and the brainstem, before reaching cortical regions associated with the ongoing task. In the course of aging, lower blue light sensitivity of some NIF functions has been reported. Here, we first describe neural pathways underlying effects of light on NIF functions and we discuss eye and cerebral mechanisms associated with aging which may affect NIF light sensitivity. Thereafter, we report results of investigations on pupillary constriction and cognitive brain sensitivity to light in the course of aging. Whereas the impact of light on cognitive brain responses appears to decrease substantially, pupillary constriction seems to remain more intact over the lifespan. Altogether, these results demonstrate that aging research should take into account the diversity of the pathways underlying the effects of light on specific NIF functions which may explain their differences in light sensitivity.

Integrin α1ß1 expression is controlled by c-MYC in colorectal cancer cells.

The α1ß1 collagen receptor is only present in a few epithelial cell types. In the intestine, it is specifically expressed in proliferating crypt cells. This integrin has been reported to be involved in various cancers where it mediates the downstream activation of the Ras/ERK proliferative pathway. We have recently shown that integrin α1ß1 is present in two-thirds of colon adenocarcinomas, but the mechanism by which ITGA1 expression is regulated is not known. DNA methylation, involved in ITGA1 repression during megakaryocyte differentiation, is not the mechanism of ITGA1 regulation in colorectal cancer cells. Our in silico analysis of the ITGA1 promoter revealed two response elements for MYC, an oncogenic factor known to regulate cancer cell proliferation, invasion and migration. In situ, the expressions of both MYC and ITGA1 are localized in the lower crypt of the normal colon and correlate in 72% of the 65 analyzed colorectal cancers. MYC pharmacological inhibition or downregulation of expression with short hairpin RNA in HT29, T84 and SW480 cells resulted in reduced ITGA1 expression at both the transcript and protein levels. Chromatin immunoprecipitation assays revealed that MYC was bound to the chromatin region of the ITGA1 proximal promoter, whereas MYC overexpression enhanced ITGA1 promoter activity that was reduced with MAD co-transfection or by the disruption of the response elements. We concluded that MYC is a key regulating factor for the control of ITGA1 expression.

Isolation and characterization of the human UGT2B15 gene, localized within a cluster of UGT2B genes and pseudogenes on chromosome 4.

Glucuronidation is a major pathway of androgen metabolism and is catalyzed by UDP-glucuronosyltransferase (UGT) enzymes. UGT2B15 and UGT2B17 are 95% identical in primary structure, and are expressed in steroid target tissues where they conjugate C19 steroids. Despite the similarities, their regulation of expression are different; however, the promoter region and genomic structure of only the UGT2B17 gene have been characterizedX to date. To isolate the UGT2B15 gene and other novel steroid-conjugating UGT2B genes, eight P-1-derived artificial chromosomes (PAC) clones varying in length from 30 kb to 165 kb were isolated. The entire UGT2B15 gene was isolated and characterized from the PAC clone 21598 of 165 kb. The UGT2B15 and UGT2B17 genes are highly conserved, are both composed of six exons spanning approximately 25 kb, have identical exon sizes and have identical exon-intron boundaries. The homology between the two genes extend into the 5'-flanking region, and contain several conserved putative cis-acting elements including Pbx-1, C/EBP, AP-1, Oct-1 and NF/kappaB. However, transfection studies revealed differences in basal promoter activity between the two genes, which correspond to regions containing non-conserved potential elements. The high degree of homology in the 5'-flanking region between the two genes is lost upstream of -1662 in UGT2B15, and suggests a site of genetic recombination involved in duplication of UGT2B genes. Fluorescence in situ hybridization mapped the UGT2B15 gene to chromosome 4q13.3-21.1. The other PAC clones isolated contain exons from the UGT2B4, UGT2B11 and UGT2B17 genes. Five novel exons, which are highly homologous to the exon 1 of known UGT2B genes, were also identified; however, these exons contain premature stop codons and represent the first recognized pseudogenes of the UGT2B family. The localization of highly homologous UGT2B genes and pseudogenes as a cluster on chromosome 4q13 reveals the complex nature of this gene locus, and other novel homologous UGT2B genes encoding steroid conjugating enzymes are likely to be found in this region of the genome.

Estimating the endogenous circadian temperature rhythm without keeping people awake.

This study was concerned with estimating endogenous temperature rhythms without imposing sleep deprivation. The aim of Experiment 1 was to quantify the masking effect on the circadian temperature rhythm in a group of 18 healthy young subjects (8 women and 10 men, ages 19-29 years). Temperature data collected under a 36-h wakeful bed rest protocol were used as a marker of the endogenous component of the rhythm ("unmasked rhythm"), and temperature data collected under 24 h of a normal nycthemeral routine (immediately before the bed rest protocol) were used as the "masked" rhythm. An algorithm to "demask" the temperature data collected under the nycthemeral condition was then developed, based on the differences observed between the temperature data collected under wakeful bed rest and nycthemeral conditions. The consistency of the demasking technique was tested in Experiment 2, using the same parameters on a group of 19 healthy elderly subjects (8 women and 11 men, ages 78-88 years) who also had experienced both nycthemeral and wakeful bed rest conditions. The demasking technique was evaluated both by comparing nycthemeral, demasked, and unmasked temperature rhythms themselves and by comparing individual estimates of circadian phase and amplitude that had been gleaned from them. In comparison to the unmasked condition, the nycthemeral condition showed lower mean nighttime temperature, earlier mean phase estimates, and higher mean amplitude estimates in both young and elderly subjects. Following application of the demasking procedure to the nycthemeral temperature data, mean demasked temperature curves were closely comparable to mean unmasked temperature curves in both young and elderly subjects. Phase and amplitude estimates derived from the demasked temperature data also were highly comparable to those in the unmasked conditions. Thus, this demasking procedure appears to be a useful tool in estimating the endogenous temperature rhythm and appears to work equally well for young and elderly subjects.