Evaluating Human Photoreceptoral Inputs from Night-Time Lights Using RGB Imaging Photometry

Night-time lights interact with human physiology through different pathways starting at the retinal layers of the eye; from the signals provided by the rods; the S-, L- and M-cones; and the intrinsically photosensitive retinal ganglion cells (ipRGC). These individual photic channels combine in complex ways to modulate important physiological processes, among them the daily entrainment of the neural master oscillator that regulates circadian rhythms. Evaluating the relative excitation of each type of photoreceptor generally requires full knowledge of the spectral power distribution of the incoming light, information that is not easily available in many practical applications. One such instance is wide area sensing of public outdoor lighting; present-day radiometers onboard Earth-orbiting platforms with sufficient nighttime sensitivity are generally panchromatic and lack the required spectral discrimination capacity. In this paper, we show that RGB imagery acquired with off-the-shelf digital single-lens reflex cameras (DSLR) can be a useful tool to evaluate, with reasonable accuracy and high angular resolution, the photoreceptoral inputs associated with a wide range of lamp technologies. The method is based on linear regressions of these inputs against optimum combinations of the associated R, G, and B signals, built for a large set of artificial light sources by means of synthetic photometry. Given the widespread use of RGB imaging devices, this approach is expected to facilitate the monitoring of the physiological effects of light pollution, from ground and space alike, using standard imaging technology.

Evaluating the Association between Artificial Light-at-Night Exposure and Breast and Prostate Cancer Risk in Spain (MCC-Spain Study)

BACKGROUND

Night shift work, exposure to light at night (ALAN) and circadian disruption may increase the risk of hormone-dependent cancers.

OBJECTIVES

We evaluated the association of exposure to ALAN during sleeping time with breast and prostate cancer in a population based multicase-control study (MCC-Spain), among subjects who had never worked at night. We evaluated chronotype, a characteristic that may relate to adaptation to light at night.

METHODS

We enrolled 1,219 breast cancer cases, 1,385 female controls, 623 prostate cancer cases, and 879 male controls from 11 Spanish regions in 2008-2013. Indoor ALAN information was obtained through questionnaires. Outdoor ALAN was analyzed using images from the International Space Station (ISS) available for Barcelona and Madrid for 2012-2013, including data of remotely sensed upward light intensity and blue light spectrum information for each geocoded longest residence of each MCC-Spain subject.

RESULTS

Among Barcelona and Madrid participants with information on both indoor and outdoor ALAN, exposure to outdoor ALAN in the blue light spectrum was associated with breast cancer [adjusted odds ratio (OR) for highest vs. lowest tertile, OR=1.47; 95% CI: 1.00, 2.17] and prostate cancer (OR=2.05; 95% CI: 1.38, 3.03). In contrast, those exposed to the highest versus lowest intensity of outdoor ALAN were more likely to be controls than cases, particularly for prostate cancer. Compared with those who reported sleeping in total darkness, men who slept in "quite illuminated" bedrooms had a higher risk of prostate cancer (OR=2.79; 95% CI: 1.55, 5.04), whereas women had a slightly lower risk of breast cancer (OR=0.77; 95% CI: 0.39, 1.51).

CONCLUSION

Both prostate and breast cancer were associated with high estimated exposure to outdoor ALAN in the blue-enriched light spectrum. https://doi.org/10.1289/EHP1837.

Physical behaviour of anthropogenic light propagation into the nocturnal environment

Propagation of artificial light at night (ALAN) in the environment is now known to have non negligible consequences on fauna, flora and human health. These consequences depend on light levels and their spectral power distributions, which in turn rely on the efficiency of various physical processes involved in the radiative transfer of this light into the atmosphere and its interactions with the built and natural environment. ALAN can affect the living organisms by direct lighting and indirect lighting (scattered by the sky and clouds and/or reflected by local surfaces). This paper mainly focuses on the behaviour of the indirect light scattered under clear sky conditions. Various interaction processes between anthropogenic light sources and the natural environment are discussed. This work mostly relies on a sensitivity analysis conducted with the light pollution radiative transfer model, Illumina (Aubé et al. 2005 Light pollution modelling and detection in a heterogeneous environment: toward a night-time aerosol optical depth retrieval method. In Proc. SPIE 2005, vol. 5890, San Diego, California, USA). More specifically, the impact of (i) the molecular and aerosol scattering and absorption, (ii) the second order of scattering, (iii) the topography and obstacle blocking, (iv) the ground reflectance and (v) the spectrum of light devices and their angular emission functions are examined. This analysis considers different behaviour as a function of the distance from the city centre, along with different zenith viewing angles in the principal plane.

α-[11C] methyl-L tryptophan-PET as a surrogate for interictal cerebral serotonin synthesis in migraine without aura

Background

Alteration in central serotonin biology has been implicated in migraine, and serotonin (5-HT) agonists have been available for more than a decade in the treatment of that condition.

Objectives

To test this hypothesis, we studied in vivo using positron-emission tomography (PET) and α-[11C] methyl-L-tryptophan (α-[11C]MTrp) as a surrogate marker of cerebral 5-HT synthetic rate before and after administration of eletriptan in migraine and control subjects.

Methods

Six nonmenopausal female migraine subjects with migraine without aura (MoA) and six nonmenopausal age-matched female control subjects were scanned at baseline and after oral administration of 40 mg of eletriptan. Migraine subjects at the time of PET had to have been headache free for a minimum of three days. Images of (α-[11C]MTrp) brain trapping were colocalized with individual MRI images in three dimensions and analyzed.

Results

There was no difference in baseline cerebral global 5-HT synthesis between migraine and control subjects. After administration of eletriptan, there was a striking global reduction in cerebral 5-HT synthesis (K*) in the migraine group and in 22 regions of interest (ROIs). In control subjects, no significant changes were found in global cerebral 5-HT synthesis (K*) or in any of the ROIs.

Conclusions

These findings suggest in migraine an interictal alteration in the regulation mechanisms of cerebral 5-HT synthesis.

Evaluating potential spectral impacts of various artificial lights on melatonin suppression, photosynthesis, and star visibility

Artificial light at night can be harmful to the environment, and interferes with fauna and flora, star visibility, and human health. To estimate the relative impact of a lighting device, its radiant power, angular photometry and detailed spectral power distribution have to be considered. In this paper we focus on the spectral power distribution. While specific spectral characteristics can be considered harmful during the night, they can be considered advantageous during the day. As an example, while blue-rich Metal Halide lamps can be problematic for human health, star visibility and vegetation photosynthesis during the night, they can be highly appropriate during the day for plant growth and light therapy. In this paper we propose three new indices to characterize lamp spectra. These indices have been designed to allow a quick estimation of the potential impact of a lamp spectrum on melatonin suppression, photosynthesis, and star visibility. We used these new indices to compare various lighting technologies objectively. We also considered the transformation of such indices according to the propagation of light into the atmosphere as a function of distance to the observer. Among other results, we found that low pressure sodium, phosphor-converted amber light emitting diodes (LED) and LED 2700 K lamps filtered with the new Ledtech’s Equilib filter showed a lower or equivalent potential impact on melatonin suppression and star visibility in comparison to high pressure sodium lamps. Low pressure sodium, LED 5000 K-filtered and LED 2700 K-filtered lamps had a lower impact on photosynthesis than did high pressure sodium lamps. Finally, we propose these indices as new standards for the lighting industry to be used in characterizing their lighting technologies. We hope that their use will favor the design of new environmentally and health-friendly lighting technologies.

[The daily public health nursing practice: the Montreal infectious diseases unit as an example]

The health of urban populations depends on multiple factors, among them access to health and social services. The Montreal Public Health Department (PHD) is part of such services, where a number of nurses are working within a multidisciplinary team. It is through the description of the work accomplished by the team for infectious diseases control and prevention, and the vignettes of real life events related to the follow-up of syphilis, tuberculosis and hepatitis A cases, as well as quarantined individual exposed to SARS that the authors want to illustrate the work of the urban public health nurses. The examples are preceded by a description of the socio-demographic characteristics of the city of Montreal, that influence health problems, and therefore nurses' work.

Non-obstructive hydrocephalus associated with intracranial schwannomas: hyperproteinorrhachia as an etiopathological factor?

BACKGROUND

This series illustrates the association of communicating hydrocephalus with intracranial non-obstructive schwannomas. This association has commonly been observed, however it has only been reported once previously. Moreover, in all the patients we present, hyperproteinorrhachia was a common denominator. This finding may therefore be the underlying mechanism for hydrocephalus.

METHOD AND FINDINGS

Seven patients presenting with intracranial schwannomas along with non-obstructive hydrocephalus and hyperproteinorrhachia are reported. Six had a vestibular schwannoma and presented with a unilateral deafness and various degrees of gait disturbance, urinary incontinence and neuropsychological impairment. Due to their advanced ages, these patients underwent a ventriculo-peritoneal shunt, and their symptoms related to hydrocephalus resolved. One patient that suffered from hemifacial dysesthesia and memory deficits presented with a non-obstructive trigeminal schwannoma. In this case the tumour was removed and the hydrocephalus was consequently reversed, and the CSF protein content normalized.

INTERPRETATION

The constant finding of hyperproteinorrhachia in all these patients suggests that a high CSF protein content may be the underlying cause of hydrocephalus through a speculative mechanism of decreased CSF resorption.

Evaluation of a modified sanitary napkin as a sample self-collection device for the detection of genital chlamydial infection in women

A modified sanitary napkin was compared with endocervical swab and urine specimens for the detection of urogenital Chlamydia trachomatis infection. Endocervical swabs and/or first-catch urine were collected from 510 women at medical or community settings in Quebec City. Participants were also asked to wear a modified sanitary napkin (Ezy-Detek) during 4 consecutive hours and to bring it back to the clinic or mail it to the laboratory. Endocervical and urine specimens were tested using the Cobas Amplicor CT/NG assay (Roche Diagnostic Systems) according to the manufacturer's instructions, as were specimens collected with the napkin after adequate preparation. If the PCR test result was positive on the endocervical sample or on any two samples, a woman was considered to be infected. PCR testing results on paired samples were identical for 493 (96.6%) of 510 women. According to the definition given above, 58 (11.3%; 95% confidence interval [CI], 8.7 to 14.5%) women were infected with C. trachomatis. The sensitivity and specificity of PCR testing on modified sanitary napkin specimens were, respectively, 93.1% (54 of 58; 95% CI, 83.3 to 98.1%) and 98.9% (447 of 452; 95% CI, 97.4 to 99.6%) compared to 81.0% (47 of 58; 95% CI, 68.6 to 90.1%) and 100% (451 of 451; 95% CI, 99.2 to 100%) for urine specimens. The positive and negative predictive values were, respectively, 91.5% (54 of 59) and 99.1% (447 of 451) for the sanitary napkin specimens compared to 100% (47 of 47) and 97.6% (451 of 462) for urine samples. These results suggest that a modified sanitary napkin represents an effective noninvasive device for self-collection of specimens to detect urogenital C. trachomatis infection.

Decreased expression of the decoy interleukin-1 receptor type II in human endometriosis

Many of the biological changes occurring in the endometrium during the menstrual cycle bear a striking resemblance to those associated with inflammatory and reparative processes. Hence, it would not be surprising to find that cytokines known for their pro-inflammatory properties, such as interleukin-1 (IL-1), could play a key role in the physiology of this tissue and that their action would be tightly controlled by local mechanisms. In the present study, immunohistochemical and Western blot analyses show that in normal women (n = 39), the endometrial tissue expresses, in a cycle-dependent manner, the IL-1 receptor type II (IL-1RII), a molecule of which the only biological property known to date is that of capturing IL-1, inhibiting thereby its binding to the functional type I IL-1 receptor. IL-RII immunostaining was particularly intense within the lumen of the glands and at the apical side of surface epithelium. Interestingly, the intensity of staining was markedly less pronounced in the endometrium of women with endometriosis (n = 54), a disease believed to arise from the abnormal development of endometrial tissue outside the uterus, especially in the early stages of the disease (stages I and II). This study is the first to show the local expression in endometrial tissue of IL-1RII, a potent and specific down-regulator of IL-1 action and its decreased expression in women suffering from endometriosis.

Cervicofacial angioma and the Kasabach-Merritt syndrome

We present a neonate with a cervicofacial haemangioma complicated by the Kasabach-Merritt syndrome, respiratory distress due to airway compression and high-output heart failure. This haemangioma and intravascular disseminated coagulation, treated initially by aspirin, ticlopidine and corticosteroids, required more invasive treatment with superselective embolisation and interferon alpha-2a. The clinical outcome was good.

Migraine in pregnancy

Migraine does not increase the risk for complications of pregnancy for the mother or for the fetus: the incidences of toxemia, miscarriages, abnormal labour, congenital anomalies, and stillbirths are comparable to those of the general population. Several retrospective studies have shown a tendency for migraine to improve with pregnancy. Between 60 and 70% of women either go into remission or improve significantly, mainly during the second and third trimesters. Women with migraine onset at menarche and those with perimenstrual migraine are more likely to go into remission during pregnancy. The migraine type does not seem to be a significant prognostic factor for improvement. However, in the small number of women (4-8%) whose migraines worsen with pregnancy, migraine with aura appears to be overrepresented. In a small number of cases (1.3-16.5%), migraine appears to start with pregnancy, often in the first trimester; these headaches involve a higher proportion of migraine with aura. Management of migraine during pregnancy should first focus on avoiding potential triggers. Consideration should also be given to nonpharmacologic therapies. If pharmacologic treatment becomes necessary, acetaminophen and codeine can be used safely as abortive agents; ASA and NSAIDs (ibuprofen, naproxen) can be used as a second choice, but not for long periods of time, and they should be avoided during the last trimester. For treatment of severe attacks of migraine, chlorpromazine, dimenhydrinate, and diphenhydramine can be used; metoclopramide should be restricted to the third trimester. According to the United States FDA risk categories, meperidine and morphine show no evidence of risk in humans but should not be used at the end of the third trimester. In some refractory cases, dexamethasone or prednisone can be considered. Should prophylactic treatment become indicated, the beta-adrenergic receptor antagonists (e.g., propranolol) can be used.

MR of nonhemorrhagic postpartum pituitary apoplexy

A 30-year-old woman had uterine bleeding and hypotension after delivery. Hyponatremic seizures and a mild headache prompted early neuroimaging, which disclosed an enlarged nonhemorrhagic pituitary gland with subsequent involution consistent with pituitary apoplexy (Sheehan syndrome). Endocrinologic investigation confirmed a partial pituitary insufficiency with subsequent improvement to almost normal status.

Migraine with vasospasm and delayed intracerebral hemorrhage

Three women with well-documented migraine associated with intracerebral hemorrhage are described. In each case, migraine headaches began during adulthood. Unusually severe and protracted headache heralded the onset of fixed neurological deficits associated with lobar intracerebral hemorrhage. Striking carotid artery tenderness was characteristic. Except for a history of migraine, no cause for intracerebral hemorrhage could be established. In each case arteriography showed extensive spasm of the appropriate extracranial or intracranial artery. Surgical pathology following evacuation of two hematomata demonstrated signs of vessel wall necrosis associated with subacute inflammatory changes. Vasospasm associated with severe migraine attacks may result in ischemia of intracranial vessel walls, leading to necrosis and subsequent vessel rupture when perfusion pressure is restored.

Human cysticercosis: a probable case of cerebral cysticercosis with generalized subcutaneous nodular lesions

A case is reported in Montreal of human cysticercosis in a 44-year-old man who emigrated from Italy in 1956. Numerous subcutaneous nodules were found throughout his body. X-ray of his thighs and chest showed oblong calcific densities measuring 1 x 0.5 cm in size. Examination of an excised nodule from the right biceps revealed a cysticercus larva morphologically similar to Cysticercus cellulosae although the scolex lacked hooks. On the basis of the intensity of infection, focal and generalized epileptic seizures, changes in the CSF, and well demarcated lucencies observed in brain scan, cerebral cysticercosis was considered the most likely diagnosis.