Journal of Investigative Medicine 

About: Journal of Investigative Medicine is an academic journal published by BMJ. The journal publishes majorly in the area(s): Medicine & Internal medicine. It has an ISSN identifier of 1081-5589. Over the lifetime, 2629 publications have been published receiving 44086 citations.

Vitamin D and the immune system.

Abstract: It is now clear that vitamin D has important roles in addition to its classic effects on calcium and bone homeostasis. As the vitamin D receptor is expressed on immune cells (B cells, T cells, and antigen-presenting cells), and these immunologic cells are all capable of synthesizing the active vitamin D metabolite, vitamin D has the capability of acting in an autocrine manner in a local immunologic milieu. Vitamin D can modulate the innate and adaptive immune responses. Deficiency in vitamin D is associated with increased autoimmunity and an increased susceptibility to infection. As immune cells in autoimmune diseases are responsive to the ameliorative effects of vitamin D, the beneficial effects of supplementing vitamin D-deficient individuals with autoimmune disease may extend beyond the effects on bone and calcium homeostasis.

Acylation targets endothelial nitric oxide synthase to plasmalemmal caveolae

Abstract: Endothelial nitric-oxide synthase (eNOS) generates the key signaling molecule nitric oxide in response to intralumenal hormonal and mechanical stimuli We designed studies to determine whether eNOS is localized to plasmalemmal microdomains implicated in signal transduction called caveolae Using immunoblot analysis, eNOS protein was detected in caveolar membrane fractions isolated from endothelial cell plasma membranes by a newly developed detergent-free method; eNOS protein was not found in noneaveolar plasma membrane Similarly, NOS enzymatic activity was 94-fold enriched in caveolar membrane versus whole plasma membrane, whereas it was undetectable in non-caveolar plasma membrane 51-86% of total NOS activity in postnuclear supernatant was recovered in plasma membrane, and 57-100% of activity in plasma membrane was recovered in caveolae Immunoelectron microscopy showed that eNOS heavily decorated endothelial caveolae, whereas coated pits and smooth plasma membrane were devoid of gold particles Furthermore, eNOS was targeted to caveolae in COS-7 cells transfected with wild-type eNOS cDNA Studies with eNOS mutants revealed that both myristoylation and palmitoylation are required to target the enzyme to caveolae and that each acylation process enhances targeting by 10-fold Thus, acylation targets eNOS to plasmalemmal caveolae Localization to this microdomain is likely to optimize eNOS activation and the extracellular release of nitric oxide

Relationship of endogenous circadian melatonin and temperature rhythms to self-reported preference for morning or evening activity in young and older people.

Abstract: BACKGROUND: Morningness-eveningness refers to interindividual differences in preferred timing of behavior (i.e., bed and wake times). Older people have earlier wake times and rate themselves as more morning-like than young adults. It has been reported that the phase of circadian rhythms is earlier in morning-types than in evening types, and that older people have earlier phases than young adults. These changes in phase have been considered to be the chronobiological basis of differences in preferred bed and wake times and age-related changes therein. Whether such differences in phase are associated with changes in the phase relationship between endogenous circadian rhythms and the sleep-wake cycle has not been investigated previously. METHODS: We investigated the association between circadian phase, the phase relationship between the sleep-wake cycle and circadian rhythms, and morningness-eveningness, and their interaction with aging. In this circadian rhythm study, 68 young and 40 older subjects participated. RESULTS: Among the young subjects, the phase of the melatonin and core temperature rhythms occurred earlier in morning than in evening types and the interval between circadian phase and usual wake time was longer in morning types. Thus, while evening types woke at a later clock hour than morning types, morning types actually woke at a later circadian phase. Comparing young and older morning types we found that older morning types had an earlier circadian phase and a shorter phase-wake time interval. The shorter phase-waketime interval in older "morning types" is opposite to the change associated with morningness in young people, and is more similar to young evening types. CONCLUSIONS: These findings demonstrate an association between circadian phase, the relationship between the sleep-wake cycle and circadian phase, and morningness-eveningness in young adults. Furthermore, they demonstrate that age-related changes in phase angle cannot be attributed fully to an age-related shift toward morningness. These findings have important implications for understanding individual preferences in sleep-wake timing and age-related changes in the timing of sleep.

Advanced body composition assessment: from body mass index to body composition profiling

Abstract: This paper gives a brief overview of common non-invasive techniques for body composition analysis and a more in-depth review of a body composition assessment method based on fat-referenced quantitative MRI. Earlier published studies of this method are summarized, and a previously unpublished validation study, based on 4753 subjects from the UK Biobank imaging cohort, comparing the quantitative MRI method with dual-energy X-ray absorptiometry (DXA) is presented. For whole-body measurements of adipose tissue (AT) or fat and lean tissue (LT), DXA and quantitative MRIs show excellent agreement with linear correlation of 0.99 and 0.97, and coefficient of variation (CV) of 4.5 and 4.6 per cent for fat (computed from AT) and LT, respectively, but the agreement was found significantly lower for visceral adipose tissue, with a CV of >20 per cent. The additional ability of MRI to also measure muscle volumes, muscle AT infiltration and ectopic fat, in combination with rapid scanning protocols and efficient image analysis tools, makes quantitative MRI a powerful tool for advanced body composition assessment.