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.     

Conformation of NAD+ bound to allosteric L-lactate dehydrogenase activated by chemical modification

On modification of arginine residues with 2,3-butanedione, the Thermus caldophilus L-lactate dehydrogenase is converted to an activated form that is independent of an allosteric effector, fructose 1,6-bisphosphate (Fru-1,6-P2). The conformation of NAD+ bound to the modified enzyme in the absence of Fru-1,6-P2 was investigated by means of proton NMR, analyzing the time dependence of the transferred nuclear Overhauser effect (TRNOE) and TRNOE action spectra. The inter-proton distances determined on TRNOE analysis indicated that both the nicotinamide riboside moiety and the adenosine moiety of NAD+ were in the anti conformation, the ribose rings being in the C3'-endo form. This conformation was almost the same as that of NAD+ bound to the native enzyme-Fru-1,6-P2 complex, rather than that of NAD+ bound to the free native enzyme. These results suggest that the C3'-endo-anti form of the enzyme-bound NAD+ is essential for the activation of the T. caldophilus L-lactate dehydrogenase.     

Characterization of revertants derived from a mouse DNA temperature-sensitive mutant strain, tsFT20, which contains heat-labile DNA polymerase alpha activity

One spontaneous and four N-methyl-N'-nitro-N-nitrosoguanidine-induced revertants of a mouse FM3A mutant, tsTF20, which has heat-labile DNA polymerase alpha activity and cannot grow at 39 degrees C, were isolated and characterized with respect to the thermolability of their DNA polymerase alpha activity, the intracellular level of enzyme activity, growth rate, cell cycle progression, and frequency of initiation of DNA replication at the origin of replicons. DNA polymerase alpha activity in the extracts from the revertant cells showed partial recovery of heat stability. The intracellular level of enzyme activity of the revertant cells was lower than that of wild-type cells even at 33 degrees C. The level of enzyme activity in the revertant cells decreased considerably after a temperature upshift to 39 degrees C, but the DNA synthesizing ability of these cells did not decrease as much as the level of enzyme activity. The growth rates of the wild-type and revertant lines were almost the same at 33 degrees C. At 39 degrees C, the rate for the wild-type increased considerably compared to that at 33 degrees C, while little difference in the growth rates of the revertant lines was observed at the two temperatures. Therefore, the doubling times of the revertant cells were relatively increased compared to those of wild-type cells cultured at the restrictive temperature. Flow microfluorometric analysis and cell cycle analysis to measure labeled mitosis revealed that the increase in the doubling time was due mainly to the increase in the duration of the S phase. Analysis of the center-to-center distance between replicons by DNA fiber autoradiography indicated that the frequency of replicon initiation per unit length DNA at a given time was reduced in the revertant cells growing at 39 degrees C.     

Freeze-fracture study of the lateral-line canal organ of the Japanese sea eel,Lincozymba nystromi

Summary Specializations of apical surfaces of hair cells, supporting cells and marginal cells in the lateral-line canal organ of Japanese sea eel, Lincozymba nystromi, were examined with a freeze-fracture technique. Apical surfaces of hair cells have a lower density of intramembrane particles (IMP) than those of the surrounding supporting cells. Density of IMP on the streocilia is almost the same as that on the apical surface of hair cells. Junctions between hair and supporting cells were tighter than those between two supporting cells; those between supporting and marginal cells were tighter than those between hair and supporting cells, and those between two marginal cells were the tightest in the lateral-line canal organ.     

Antibody-dependent cell-mediated cytotoxicity using a murine monoclonal antibody against human colorectal cancer in cancer patients

Summary Antibody-dependent cell-mediated cytotoxicity (ADCC) mediated by a murine monoclonal antibody against human colerectal carcinoma, antibody 19–9, with human effector cells was tested in 33 patients with various carcinomas, 16 patients with benign lesions, and 13 normal controls, using a 12-h ⁵¹Cr release assay using human colorectal cancer cells as targets. Peripheral blood mononuclear cells (PBM) from these groups of patients and normal controls achieved moderate levels of target cell lysis in the presence of the monoclonal antibody at the high effector to target cell ratio of 200:1. The ADCC activity of PBM in cancer patients was significantly higher than that in either normal persons or patients with benign lesions. Since the ADCC was shown to be mainly mediated by adherent monocytes in the PBM, ADCC activity of monocytes from cancer patients was compared to those from control groups at an effector to target cell ratio of 30:1. The results also showed that the lytic capacity of monocytes was significantly higher in cancer patients than that in the control populations.     

Effect of UV-B (290–320 nm) irradiation on growth and metabolism of cucumber cotyledons

Cucumber ( Cucumis sativus L. cv. Natsusairaku 3) seedlings were grown in a growth cabinet under UV-B (290–320 nm) irradiation (equivalent to the UV-B radiation normally incident at Tokyo, 36°N latitude, during clear sky conditions in mid-april on a weighted daily fluence basis) and a UV-B-free control condition. UV-B irradiation inhibited the growth of the cotyledons, i.e. the increase in area, and increase in fresh and dry weights of the cotyledons. The greatest inhibition rate was observed in the increase in area, causing a significant increase in specific leaf weight (the ratio of weight to area). UV-B irradiation had no significant effect on DNA and RNA contents in the cotyledons, but decreased protein content slightly. In contrast, the irradiation reduced the amounts of organic acids and soluble sugars, indicating that primary carbon metabolism was very sensitive to UV-B radiation. UV-B irradiation lowered the photosynthetic activity in the cotyledons without any effect on chlorophyll content and respiratory activity. These results indicate that UV-B radiation at the ambient level may act as a physiological stress in some UV-sensitive plants.     

Effect of histamine H1-receptor antagonist on the regulation of carbohydrate and lipid metabolism in rat liver

In order to elucidate the role of histamine in the liver, we studied the effect of a histamine H1-receptor antagonist on the carbohydrate and lipid metabolism in the rat liver. The administration of the H1-receptor antagonist decreased significantly the contents of glycogen and malonyl-CoA in the liver. However, it did not affect the levels of serum glucose and free fatty acid. These results suggest that histamine may play a part in the regulation of metabolism of carbohydrates and lipids in the liver.