Association between light exposure at night and manic symptoms in bipolar disorder: cross-sectional analysis of the APPLE cohort

ABSTRACT

Previous studies have found that keeping the room dark at night was associated with a decrease in manic symptoms for patients with bipolar disorder (BD). However, the association between light at night of real-life conditions and manic symptoms is unclear. We investigated the association between bedroom light exposure at night and manic symptoms in BD patients. One-hundred and eighty-four outpatients with BD participated in this cross-sectional study. The average light intensity at night during sleep was evaluated using a portable photometer for seven consecutive nights. Manic symptoms were assessed using the Young Mania Rating Scale (YMRS), and scores ≥5 were treated as a “hypomanic state.” The median (interquartile range) YMRS score was 2.0 (0–5.0), and 52 (28.2%) participants were in a hypomanic state. The prevalence of a hypomanic state was significantly higher in the participants with an average light intensity at night exposure of ≥3 lux than in those with <3 lux (36.7% versus 21.9%; P = .02). In multivariable logistic regression analysis adjusted for BD type, depressive symptoms, sleep duration, and daytime physical activity, the odds ratio (OR) for a hypomanic state was significantly higher for the participants with an average light intensity at night exposure of ≥3 lux than for those with <3 lux (OR: 2.15, 95% confidence interval: 1.09–4.22, P = .02). This association remained significant at the cutoff value of YMRS score ≥6 (OR: 2.51, 95% confidence interval: 1.15–5.46; P = .02). The findings of this study indicate bedroom light exposure at night is significantly associated with manic symptoms in BD patients. Although the results of this cross-sectional investigation do not necessarily imply causality, they may serve to inform beneficial nonpharmacological intervention and personalized treatment of BD patients.     

Protective Effect of External Ca2+ on Elongation and the Intracellular Concentration of K+ in Intact Mung Bean Roots under High NaCl Stress

The effects of Ca²⁺ in the external medium on intact mung beanroots under high NaCl stress were investigated. With increasingexternal concentrations of NaCl, mung bean roots showed suppressionof elongation and a decrease in the intracellular concentrationof K⁺. Addition of Ca²⁺ to the external medium alleviated theinhibition of root elongation under the high NaCl stress andmaintained a high intracellular concentration of K⁺ in the elongatingregion of the roots. This counter effect of Ca²⁺ against theNaCl stress on roots was correlated with the ratio of [Ca²⁺]/[Na⁺]²in the external medium. A value above 5.0 ? 10^–4 mM^–1resulted in almost complete recovery of root elongation undervarious high concentrations of NaCl. Root elongation for 24h under NaCl stress was correlated with the extent to whichthe intracellular concentration of K⁺ was in excess of 10 mM.Maintenance of an adequate concentration of K⁺ in root cellsis essential for root elongation under salt stress. These findingsindicate that Ca²⁺ prevents the leakage of intracellular K⁺and thereby supports the elongation of roots under salt stress. (Received November 13, 1989; Accepted June 5, 1990)     

Changes in Targeting Efficiencies of Proteins to Plant Microbodies Caused by Amino Acid Substitutions in the Carboxy-terminal Tripeptide

It has been demonstrated that the carboxyl terminus of microbodyenzymes functions as a targeting signal to microbodies in higherplants. We have examined an ability of 24 carboxy-terminal aminoacid sequences to facilitate the transport of a cytosolic passengerprotein, ß-glucuroni-dase, into microbodies in greencotyledonary cells of trans-genic Arabidopsis. Immunoelectronmicroscopic analysis revealed that carboxy-terminal tripeptidesequences of the form [C/A/S/P]-[K/R]-[I/L/M] function as amicrobody-targeting signal, although tripeptides with prolineat the first amino acid position and isoleucine at the carboxylterminus show weak targeting efficiencies. All known micro-bodyenzymes that are synthesized in a form similar in size to themature molecule, except catalase, contain one of these tripeptidesequences at their carboxyl terminus. (Received April 14, 1997; Accepted April 8, 1997)     

New peptide alkaloids from Hovenia dulcis and H. tomentella

From the root bark of Hovenia dulcis Thunb. and H. tommentella (Makino) Nakai (Rhamnaceae), three peptide alkaloids, frangulanine, hovenins-A and -B have been isolated. Hovenin-A has been shown to be des-N-methylfrangulanine (II).     

AERENCHYMA DEVELOPMENT IN WATERLOGGED PLANTS

Aerenchyma development in waterlogged Helianthus annuus, Lycopersicon esculentum, and Salix fragilis was studied. More than half of the root cortical tissue sometimes became an air cavity in willow roots which developed in water. There was no cortical aerenchyma in the terminal portion, but more advanced aerenchyma developed towards the base of the sunflower roots formed in water. Waterlogged sunflower and tomato plants developed lysigenous aerenchyma in the cortex of waterlogged stems within two days.     

Characterization of Avian Paramyxoviruses Isolated from Feral Ducks in Northern Japan: The Presence of Three Distinct Viruses in Nature

Seventy-eight strains of avian paramyxoviruses (PMV) were isolated from cloacal and/or tracheal swabs taken from 1,342 feral ducks, comprised of spot-bill ducks, mallards, pintails, teals, falcated teals, wigeons and buffie-heads, in Wakuya-cho, Miyagi Prefecture, Japan, between 1976 and 1979. Five and a half percent of the ducks were positive for virus. Serological and structural characterization indicated that three different avian paramyxoviruses arc prevalent in the Japanese feral duck population. The first group of PMV was Newcastle disease virus (NDV), and in vivo pathogenecity tests in embryonated chicken eggs and 1-day-old chicks revealed that all the NDV strains isolated were avirulent. The second and most prevalent strain was closely related to PMV-4, duck/Hong Kong/D3/75 strain. The viruses of the third group were recovered only from pintails. They cross-reacted antigenically with PMV-3 when antisera to the PMV-3 reference strains, turkey/Wisconsin/68 and parakeet/Netherlands/449/75, were employed. However, no cross-reaction was observed when antiserum to pintail/ Wakuya/20/78, the prototype of this group, was used. The viruses of the third group also differed in viral polypeptide profile from the reference strains of PMV-3.     

Molecular cloning of a non-isopeptide-selective human endothelin receptor.

We isolated several complementary DNA (cDNA) clones encoding a non-isopeptide-selective human endothelin receptor (ETBR) from a human placenta cDNA library. The clones, different in the length of their 3'-untranslated regions, encoded the same 442-amino acid protein with a transmembrane topology similar to that of other G protein-coupled receptors. The rank order of the binding of ET isopeptides (ET-1, ET-2 and ET-3) to the receptor expressed in COS-7 cells was ET-1 = ET-2 = ET-3. Northern blot analysis identified three mRNA species, 4.3 kb, 2.7 kb and 1.7 kb in size, probably generated by their use of alternative polyadenylation sites. These mRNAs were expressed in a wide variety of human tissues, at the highest level in the brain and at a significant level in cultured endothelial cells.     

Induction and Secretion of Pathogenesis-Related Proteins by Salicylate or Plant Hormones in Tobacco Suspension Cultures

Pathogenesis-related proteins (PR proteins), that are inducedin tobacco leaves in hypersensitive response to infection withtobacco mosaic virus (TMV) or by treatment with chemicals, werefound to be also inducible in a dedifferentiated system, tobaccosuspension culture. Quantitative determination of these proteinsusing anti PR 1a IgG showed that their increase started at aboutthe end of cell growth period and that their production couldbe enhanced by the addition of potassium salicylate, Eosin Yellowishand plant hormones (GA3, IAA and 2,4-D). The production dependedon the concentration of the chemical inducer and the cell lineused. In BY-2 cell line, PR proteins amounted to 12 µgat day 5 and then increased exponentially with time, reaching280 µg or 70 µg per g fr wt of cells at day 9 withor without the addition of 25 µM potassium salicylate.More than 90% of the induced PR proteins was found in the mediumand less than 10% in the cells at day 9. Peroxidase activityin the medium was constant throughout the experiment althoughtotal activity in the flask increased with cell growth, indicatingthat PR proteins are actively secreted into the medium. (Received November 12, 1986; Accepted March 6, 1987)