Thick methacrylate sections devoid of lost caps simplify stereological quantifications based on the optical fractionator design.

In neuroscience, the optical fractionator technique is frequently used for unbiased cell number estimations. Although unbiased in theory, the practical application of the technique is often biased by the necessity of introducing a guard zone at one side of the disector to counter lost caps and/or optical limitations. Restricting the disector within the section thickness potentially introduces bias in two ways.

Associations between xerostomia, histopathological alterations, and autonomic innervation of labial salivary glands in men in late midlife.

Objective: One aim of the present study was to investigate whether symptoms of oral dryness (xerostomia) during daytime, assessed in a study group of middle-aged male positive and negative outliers in cognition scores, were associated with age-related degenerative changes in human labial salivary glands and with quantitative measures of the glandular autonomic innervation. Another aim was to study the relation between the autonomic innervation and loss of secretory acinar cells in these glands.

Methods: Labial salivary gland biopsies were taken from the lower lip from 190 men, born in 1953 and members of the Danish Metropolit birth cohort, who were examined for age-related changes in cognitive function and dental health as part of the Copenhagen University Center for Healthy Aging clinical neuroscience project.

Concentration-dependent neurotoxicity of articaine: an electrophysiological and stereological study of the rat sciatic nerve.

Background: We performed this study to quantify the detrimental effect of intraneural injection of 50 μL of saline, articaine 2%, or articaine 4% in the rat sciatic nerve.

Methods: Lumbar-evoked electrospinograms from stimulation of the sciatic nerve were recorded before and immediately after injection and again after 3 weeks. Test substance was injected into the right sciatic nerve, and the untreated left sciatic nerve served as control.

Lower strength of the human posterior patellar tendon seems unrelated to mature collagen cross-linking and fibril morphology.

The human patellar tendon is frequently affected by tendinopathy, but the etiology of the condition is not established, although differential loading of the anterior and posterior tendon may be associated with the condition. We hypothesized that changes in fibril morphology and collagen cross-linking would parallel differences in material strength between the anterior and posterior tendon. Tendon fascicles were obtained from elective ACL surgery patients and tested micromechanically.

Vitamin C deficiency in early postnatal life impairs spatial memory and reduces the number of hippocampal neurons in guinea pigs.

Background: The neonatal brain is particularly vulnerable to imbalances in redox homeostasis because of rapid growth and immature antioxidant systems. Vitamin C has been shown to have a key function in the brain, and during states of deficiency it is able to retain higher concentrations of vitamin C than other organs. However, because neurons maintain one of the highest intracellular concentrations of vitamin C in the organism, the brain may still be more sensitive to deficiency despite these preventive measures.