Dynamic white lighting to aid sleep and vision for persons living with dementia using off-the-shelf LED strips.

Alzheimer disease and related dementias affect 15-20% of elderly people, and 60-70% of these suffer from sleep disturbances. Studies suggest that lighting can improve sleep. The key challenge is how to deliver light effectively. We have designed a lighting system that adjusts spectrum and irradiance on a 24-hour timetable to provide spatially uniform, shadow-free white light with CRI>85 and up to 1000 Lux for day vision and amber light for night vision. To aid sleep, melanopic illuminance varies over 3 orders of magnitude to enable strong suppression of melatonin in the morning/early afternoon, moderate suppression in the evening, and no suppression at night.

The role of luminal factors in the recovery of gastric function and behavioral changes after chronic Helicobacter pylori infection.

The role of chronic infections, such as Helicobacter pylori (Hp), to produce sustained changes in host physiology remains controversial. In this study, we investigate whether the antigenic or bacterial content of the gut, after Hp eradication, influences the changes in gut function induced by chronic Hp infection. Mice were infected with Hp for 4 mo and then treated with antibiotics or placebo for 2 wk. Gastric emptying was measured using videofluoroscopy, feeding behavior using a 24-h feeding system, and intestinal permeability using an isolated jejunal segment arterially perfused with an artificial oxygen carrier, hemoglobin vesicles. Immune responses were assessed by CD3(+) cell counts and anti-Hp antibodies using ELISA. To determine the role of luminal factors in host physiology posteradication, groups of mice received the probiotics containing Lactobacillus rhamnosus R0011 and L. helveticus R0052 or placebo for 2 wk or crude Hp antigen weekly for 2 mo. Chronic Hp infection was associated with delayed gastric emptying, increased intestinal permeability, and increased gastric CD3(+) cell counts. Hp-induced altered feeding patterns did not reverse after eradication. Probiotics accelerated the recovery of paracellular permeability and delayed gastric emptying, improved the CD3(+) cell counts, and normalized altered feeding patterns posteradication. Hp antigen resulted in increased anti-Hp antibodies and increased CD3(+) cell counts in the stomach and delayed recovery of gastric function. Our results suggest that the bacterial content of the gut, as well as the presence of relevant antigens, influences the rate of recovery of host pathophysiology induced by chronic Hp infection. These changes do not seem to occur in association with modulation of intestinal permeability.

Visceral pain perception is determined by the duration of colitis and associated neuropeptide expression in the mouse.

BACKGROUND: Even though inflammation is a traditional tool for the induction of hyperalgesia in many tissues, recent observations suggest that not all inflammatory processes produce this change. Tolerance to colorectal distension (CRD) is reduced in patients with acute ulcerative colitis but is increased in patients with chronic inflammatory bowel disease. This suggests that the nature of the inflammatory infiltrate influences visceral perception. AIM: To test this hypothesis by assessing responses to CRD in mice with mild, acute or chronic colitis. METHODS: CRD responses were measured in mice with mild non-specific colitis, and dextran sodium sulphate (DSS)-induced acute and chronic colitis. Responses were compared with tissue infiltrate and damage, interleukin (IL)1beta and myeloperoxidase (MPO) activity and substance P, beta-endorphin and micro opioid receptor (MOR) expression. RESULTS: Mild and acute colitis were associated with increased responsiveness to CRD. In contrast, CRD responses were not increased in mice with chronic colitis and this difference was not due to altered colonic wall compliance. MPO and IL1beta levels were greater in acute than in chronic colitis. Larger increases in tissue substance P were seen in acute than in chronic DSS, whereas CD4 T cells, beta-endorphin and MOR expression were evident only in chronic colitis. An inverse correlation was seen between substance P and MOR in these tissues. CONCLUSIONS: Acute colitis increased responsiveness to CRD and is accompanied by an acute inflammatory infiltrate and increased tissue substance P. Chronic DSS is accompanied by an increase in beta-endorphin and MOR expression, and CD4 T cells, but no change in compliance or CRD responses. We conclude that acute inflammation generates hyperalgesia, whereas chronic inflammation involves infiltration by lymphocytes accompanied by MOR and beta-endorphin up regulation, and this provides an antinociceptive input that restores normal visceral perception.

The effects of pulse configuration on magnetic stimulation.

A study is presented in which the authors have examined the effects of pulse configuration, stimulation intensity, and coil current direction during magnetic stimulation. Using figure-8 and circular coils, the median nerve was stimulated at the cubital fossa and at the wrist of 10 healthy volunteers, and the response amplitude and site of stimulation were determined. The key findings of this study are in agreement with other researchers' findings and confirm that biphasic stimulating pulses produce significantly higher M-wave amplitudes than monophasic stimulating pulses for the same stimulus intensity. Mean response amplitudes for biphasic stimuli applied by both coils at the elbow and wrist are consistently higher for the normal current direction. Mean response amplitudes for monophasic pulses are almost always higher for reversed currents. The site for effective stimulation (the position of the virtual cathode) cannot be defined within a fixed distance from the center of the coil (3 to 4 cm), as has been suggested by other researchers, but was found to vary depending on the coil current amplitude and direction as well as the degree of inhomogeneity of the tissues surrounding the nerve. There is a statistically significant relationship between virtual cathode shift and stimulus intensity for biphasic and monophasic pulses. Reversing the coil current direction has no statistically significant effect on the virtual cathode position. Virtual cathode shifts can be measured for biphasic and monophasic stimulations using a figure-8 coil at the wrist and the elbow. However, such a shift is difficult to determine with a circular coil.