Distribution of voltage-gated potassium and hyperpolarization-activated channels in sensory afferent fibers in the rat carotid body

The chemosensory glomus cells of the carotid body (CB) detect changes in O2 tension. Carotid sinus nerve fibers, which originate from peripheral sensory neurons located within the petrosal ganglion, innervate the CB. Release of transmitter from glomus cells activates the sensory afferent fibers to transmit information to the nucleus of the solitary tract in the brainstem. The ion channels expressed within the sensory nerve terminals play an essential role in the ability of the terminal to initiate action potentials in response to transmitter-evoked depolarization. However, with a few exceptions, the identity of ion channels expressed in these peripheral nerve fibers is unknown. This study addresses the expression of voltage-gated channels in the sensory fibers with a focus on channels that set the resting membrane potential and regulate discharge patterns. By using immunohistochemistry and fluorescence confocal microscopy, potassium channel subunits and HCN (hyperpolarization-activated) family members were localized both in petrosal neurons that expressed tyrosine hydroxylase and in the CSN axons within the carotid body. Channels contributing to resting membrane potential, including HCN2 responsible in part for I(h) current and the KCNQ2 and KCNQ5 subunits thought to underlie the neuronal "M current," were identified in the sensory neurons and their axons innervating the carotid body. In addition, the results presented here demonstrate expression of several potassium channels that shape the action potential and the frequency of discharge, including Kv1.4, Kv1.5, Kv4.3, and K(Ca) (BK). The role of these channels should be considered in interpretation of the fiber discharge in response to perturbation of the carotid body environment.     

老年病筛查与预防

世界正在步人老龄化社会,2000年≥60岁的人口占总人口的10%;预计2050年这个数字将升至2l%.因此老年人群的预防保健需求日益凸显出来,但预防医学研究很少涵盖≥65岁人群.本文对引起死亡的疾病和影响因素,老年病筛查和预防进行了详细的论述.     

Atopic dermatitis in older patients: particular points

We review the particular characteristics of atopic dermatitis (AD) in adult life, and compare findings with those of AD in childhood. AD affects 1–3% of adults world‐wide, and can present as adult‐onset AD, or as infantile/childhood AD that persists, or recurs after many years. Eczema in adults usually exists for years, compromising quality of life, sex life and occupational choices. The flexural areas, shoulders, head‐and‐neck, and hands are typically affected. In elderly adults, eczematous erythroderma is common. The intrinsic (non‐IgE‐allergic) eczema subtype affects 5–15% of cases. Classical food allergy has a low importance, although non‐IgE‐mediated and pseudoallergic reactions can cause eczema. Sensitivity to aeroallergens, especially dust mite, is demonstrated in the majority of adult AD patients, including elderly adults, by immunoglobulin E‐mediated tests and/or atopy patch tests. Occupational allergic and irritant contact dermatitis is increased. In adults, as in children, Staphylococcus aureus colonization is very high, whereas adult skin is more heavily colonized with Malassezia yeasts. Immediate and delayed sensitization to Malassezia sympodialis is specific for intrinsic and extrinsic AD, occurring especially in head‐and‐neck eczema. Concerning therapy, older patients are prone to certain adverse drug effects. In conclusion, differences exist between childhood and adult disease. As we should be seeing more adults with AD in the future, there is a need for more clinical and immunological studies in older patients.     

A human cadaveric workshop: One solution to competence in the face of rarity

Competent performance of cricothyroidotomy, lateral canthotomy and resuscitative thoracostomy is an expected standard for Australasian emergency physicians, but infrequent exposure to these procedures could impair physician confidence, reducing the likelihood of their execution in a critical timeframe. Training to perform these procedures is a recognised challenge for non‐surgeons, and cadaver‐based training is one method of addressing this need. We describe a 1 day cadaver‐based workshop for emergency medicine doctors and briefly report on its impact on physician confidence. This workshop appeared effective in increasing the confidence of emergency medicine physicians to carry out rarely performed life and sight‐saving procedures and also provides an opportunity for senior clinicians to increase compliance with continuing profession development schemes.     

Increased cerebral vascular reactivity in the tau expressing rTg4510 mouse: evidence against the role of tau pathology to impair vascular health in Alzheimer's disease

Vascular abnormalities are a key feature of Alzheimer''s disease (AD). Imaging of cerebral vascular reactivity (CVR) is a powerful tool to investigate vascular health in clinical populations although the cause of reduced CVR in AD patients is not fully understood. We investigated the specific role of tau pathology in CVR derangement in AD using the rTg4510 mouse model. We observed an increase in CVR in cortical regions with tau pathology. These data suggest that tau pathology alone does not produce the clinically observed decreases in CVR and implicates amyloid pathology as the dominant etiology of impaired CVR in AD patients.