Denervation of neuromuscular junctions in the extensor digitorum longus of aging mice

How does the connection morphology of motor neuron axons and muscle fiber endplates change with age? Chai et al recently published some results addressing, in part, this question. Their study compared young 3 month and geriatric 29 month old mice, which, as the authors note, correspond to roughly 20 and 80 years in humans, respectively. [...]

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Proteins differentially expressed in the aging hippocampus

In their review of the “neuroproteome” associated with aging and cognitive decline, VanGuilder and Freeman discuss some of the technical approaches and findings in the field. This illustrative figure shows some of the major cellular players involved and lists some example proteins involved in four important pathways: As you can see, many proteins have been implicated, [...]

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Synaptic pruning in the mediodorsal thalamus

More neurons are born than necessary, and synaptic pruning is the process by which neurons that have not made as many functional synaptic connections with other neurons are preferentially degraded. Abitz et al counted cells in the medial thalamus of newborn and adult brains using a optical fractionator and Giemsa staining which binds to phosphate [...]

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Changes in myelinated axons following juggling in diffusion tensor imaging

Scholz et al performed diffusion tensor imaging on 48 adults randomly placed in either a juggling or control group. By the end of the 6-week training each of the adults in the juggling group could perform 2 cycles of the 3 ball cascade, which is somewhat but not overly impressive. As compared to their pre-scanning [...]

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Decline in hippocampal plasticity mediated by deficits in D-serine

Most naturally occuring amino acids in animals are of the L stereoisomerism, but D-serine is an amino acid that does have biological activity. It is known to activate NMDA receptors and induce NDMA receptor-dependent synaptic plasticity. And, there is evidence that deficiencies in D-serine are involved in the decline in hippocampus-dependent memory that occurs during [...]

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Beta amyloid precursor promotes synaptogenesis

Amyloid precursor protein (APP) is heavily implicated in the progression of Alzheimer’s disease. When proteolytically processed they yield 40 and 42 amino acid amyloid peptides which form the beta amyloid plaques one often hears about.  APP/APLP2double knock-out mice have reduced protein expression at the neuromuscular synapse and have generally defective synapses. Wang et al have [...]

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Tau protein as cerebrospinal fluid markers in Alzheimer’s Disease

Buckhave et al have some interesting results from a longitudinal study of 119 patients with AD. At baseline, CSF levels of the microtubule-associated tau protein was significantly higher in both AD cohorts (693±301 nanograms per liter and 663±308 ng/l) than in the control group (412±232 ng/l). Additionally, baseline CSF levels of beta amyloid were lower [...]

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Variability to apoptotic response mediated by functional protein levels

When aptosis is induced in cell populations with tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), there is a surprising amount of variation in both how long it takes for cells to die and whether or not they will ever do so. For example, when exposed to 50 nanograms of TRAIL and cycloheximide, some mammary gland cells [...]

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Genetic correlates of long age

There have been sparce tests of genome-wide associations between gene expression and longevity in humans, but more are coming up the pipeline. Kerber et al (2009) used a dataset of Utah grandmothers to test 2151 always expressed genes in a proportional hazards model. The predicted mortality from their six gene model was able to account [...]

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Stress and culture

It is interesting to compare how measures of psychological stress differ across cultures. The Whitehall study, a longitudinal study to determine the social correlates of health, has been going since 1967. Since it evaluates civil servants with the same access to healthcare in the same general living circumstances, it has been able to control for [...]

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