Dark Rearing Promotes the Recovery of Visual Cortical Responses but Not the Morphology of Geniculocortical Axons in Amblyopic Cat

Monocular deprivation (MD) of vision during early postnatal life induces amblyopia, and most neurons in the primary visual cortex lose their responses to the closed eye. Anatomically, the somata of neurons in the closed-eye recipient layer of the lateral geniculate nucleus (LGN) shrink and their axons projecting to the visual cortex retract. Although it has been difficult to restore visual acuity after maturation, recent studies in rodents and cats showed that a period of exposure to complete darkness could promote recovery from amblyopia induced by prior MD. However, in cats, which have an organization of central visual pathways similar to humans, the effect of dark rearing only improves monocular vision and does not restore binocular depth perception. To determine whether dark rearing can completely restore the visual pathway, we examined its effect on the three major concomitants of MD in individual visual neurons, eye preference of visual cortical neurons and soma size and axon morphology of LGN neurons. Dark rearing improved the recovery of visual cortical responses to the closed eye compared with the recovery under binocular conditions. However, geniculocortical axons serving the closed eye remained retracted after dark rearing, whereas reopening the closed eye restored the soma size of LGN neurons. These results indicate that dark rearing incompletely restores the visual pathway, and thus exerts a limited restorative effect on visual function

Abnormal localized [¹⁸F]FDG accumulation in a Hoffman 3D brain phantom caused by Pseudomonas aeruginosa and Stenotrophomonas maltophilia

The version of record of this article, first published in European Journal of Nuclear Medicine and Molecular Imaging, is available online at Publisher’s website: https://doi.org/10.1007/s00259-024-06816-5.Hoffman 3D brain phantom was scanned to standardize the image quality in a clinical trial. Dynamic [¹⁸F]fluorodeoxyglucose positron emission tomography ([¹⁸F]FDG PET), which started 15 min after being filled with [¹⁸F]FDG (25 MBq), revealed an abnormally increasing accumulation of [¹⁸F]FDG in the left occipital cortex region at one hour. This abnormal accumulation showed an increasing trend (Fig. 1A, B). The presence of bacteria was suggested by the culture of scrabbed samples taken from the corresponding region in the phantom, later confirmed to be Pseudomonas aeruginosa and Stenotrophomonas maltophilia (Fig. 1C). Pseudomonas aeruginosa is an aerobic Gram-negative rod with a single flagellum at one end. It is a facultative anaerobic bacterium that generates ATP (adenosine triphosphate) necessary for growth by aerobic respiration and grows by oxidative degradation of glucose in the presence of oxygen [1]. Stenotrophomonas maltophilia is a non-fermentative Gram-negative bacterium that consumes proteins and peptides rather than sugars and carbohydrates as carbon and nutrient sources [2]. There have been several reports on the uptakes of [¹⁸F]FDG [3, 4]. We concluded that the abnormal accumulation was caused by FDG-avid bacterium, Pseudomonas aeruginosa and Stenotrophomonas maltophilia.It is preferable to use degassed tap water rather than purified or distilled water to prevent the growth of bacteria. Hoffman 3D brain phantom should be disassembled and completely dried after the scan, especially for multicenter clinical trials

Cognitive dysfunction and amyloid β accumulation are ameliorated by the ingestion of green soybean extract in aged mice

AbstractThe effects of soybean extracts were investigated in senescence-accelerated (SAMP10) mice, a mouse model of brain senescence with cognitive dysfunction. Mature soybeans are usually yellow. However, the green soybean retains green color after being ripened. Cognitive functions were significantly better-preserved in aged mice fed green soybean than age-matched control mice with or without yellow soybean feeding. Molecular mechanisms of the beneficial effect of green soybean on brain functions were examined through transcriptome analysis of SAMP10 hippocampus. The high expression of Ptgds was significantly associated with green soybean diet, which encodes lipocalin-type prostaglandin D2 synthase, a putative endogenous amyloid β(Αβ)-chaperone. In consonance, Aplp1 expression was significantly reduced, a member of amyloid precursor proteins. Furthermore, the amount of Aβ 40 and 42 was reduced in the insoluble fraction of cerebral cortex. These results suggest that the intake of green soybean ameliorates cognitive dysfunction of aged mice through the reduction of Aβ accumulation

Oolong tea increases energy metabolism in Japanese females

Oolong tea is a traditional Chinese tea that has long been believed to be beneficial to health such as decreasing body fat. We were interested in this assertion and tried to evaluate the effect of oolong tea on energy expenditure (EE) in comparison with green tea. The subjects were eleven healthy Japanese females (age 20±1 y body mass index(BMI) 21.2±2.5kg/m2)who each consumed of three treatments in a crossover design : 1) water, 2) oolong tea, 3) green tea. Resting energy expenditure (REE) and EE after the consumption of the test beverage for 120 min were measured using an indirect calorimeter. The cumulative increases of EE for 120 min were significantly increased 10% and 4% after the consumption of oolong tea and green tea, respectively. EE at 60 and 90 min were significantly higher after the consumption of oolong tea than that of water (Plt0.05). In comparison with green tea, oolong tea contained approximately half the caffeine and epigallocatechin galate, while polymerized polyphenols were double. These results suggest that oolong tea increases EE by its polymerized polyphenols

Circadian protection against bacterial skin infection by epidermal CXCL14-mediated innate immunity

体内時計は夜間に自然免疫を発動 --皮膚ケモカインによる自然免疫機構--. 京都大学プレスリリース. 2022-06-16.Biological clocks set for skin immunity. 京都大学プレスリリース. 2022-06-21.The epidermis is the outermost layer of the skin and the body’s primary barrier to external pathogens; however, the early epidermal immune response remains to be mechanistically understood. We show that the chemokine CXCL14, produced by epidermal keratinocytes, exhibits robust circadian fluctuations and initiates innate immunity. Clearance of the skin pathogen Staphylococcus aureus in nocturnal mice was associated with CXCL14 expression, which was high during subjective daytime and low at night. In contrast, in marmosets, a diurnal primate, circadian CXCL14 expression was reversed. Rhythmically expressed CXCL14 binds to S. aureus DNA and induces inflammatory cytokine production by activating Toll-like receptor (TLR)9-dependent innate pathways in dendritic cells and macrophages underneath the epidermis. CXCL14 also promoted phagocytosis by macrophages in a TLR9-independent manner. These data indicate that circadian production of the epidermal chemokine CXCL14 rhythmically suppresses skin bacterial proliferation in mammals by activating the innate immune system

Crystal structure of glutamine receptor protein from Sulfolobus tokodaii strain 7 in complex with its effector l-glutamine: implications of effector binding in molecular association and DNA binding

Genome analyses have revealed that members of the Lrp/AsnC family of transcriptional regulators are widely distributed among prokaryotes, including both bacteria and archaea. These regulatory proteins are involved in cellular metabolism in both global and specific manners, depending on the availability of the exogenous amino acid effectors. Here we report the first crystal structure of glutamine receptor protein (Grp) from Sulfolobus tokodaii strain 7, in the ligand-free and glutamine-bound (Grp-Gln) forms. Although the overall structures of both molecules are similar, a significant conformational change was observed at the ligand [l-glutamine (Gln)] binding site in the effector domain, which may be essential for further stabilization of the octameric structure, and in turn for facilitating DNA binding. In addition, we predicted promoter for the grp gene, and these analyses suggested the importance of cooperative binding to the protein. To gain insights into the ligand-induced conformational changes, we mutated all of the ligand-binding residues in Grp, and revealed the importance of Gln binding by biochemical and structural analyses. Further structural analyses showed that Y77 is crucial for ligand binding, and that the residues T132 and T134, which are highly conserved among the Lrp family of proteins, fluctuates between the active and inactive conformations, thus affecting protein oligomerization for DNA binding