Sialic acids attached to N- and O-glycans within the Nav1.4 D1S5-S6 linker contribute to channel gating.

Background: Voltage-gated Na+ channels (Nav) are responsible for the initiation and conduction of neuronal and muscle action potentials. Nav gating can be altered by sialic acids attached to channel N-glycans, typically through isoform-specific electrostatic mechanisms.

Methods: Using two sets of Chinese Hamster Ovary cell lines with varying abilities to glycosylate glycoproteins, we show for the first time that sialic acids attached to O-glycans and N-glycans within the Nav1.

Regulated and aberrant glycosylation modulate cardiac electrical signaling.

Millions afflicted with Chagas disease and other disorders of aberrant glycosylation suffer symptoms consistent with altered electrical signaling such as arrhythmias, decreased neuronal conduction velocity, and hyporeflexia. Cardiac, neuronal, and muscle electrical signaling is controlled and modulated by changes in voltage-gated ion channel activity that occur through physiological and pathological processes such as development, epilepsy, and cardiomyopathy. Glycans attached to ion channels alter channel activity through isoform-specific mechanisms.

Voltage-gated Na+ channels confer invasive properties on human prostate cancer cells.

Prostate cancer is the second leading cause of cancer deaths in American males, resulting in an estimated 37,000 deaths annually, typically the result of metastatic disease. A consequence of the unsuccessful androgen ablation therapy used initially to treat metastatic disease is the emergence of androgen-insensitive prostate cancer, for which there is currently no prescribed therapy. Here, three related human prostate cancer cell lines that serve as a model for this dominant form of prostate cancer metastasis were studied to determine the correlation between voltage-gated sodium channel expression/function and prostate cancer metastatic (invasive) potential: the non-metastatic, androgen-dependent LNCaP LC cell line and two increasingly tumorogenic, androgen-independent daughter cell lines, C4 and C4-2.

Age-related variations in hematologic and plasma biochemical test results in Beagles and Labrador Retrievers.

Objective: To investigate age-related variations in results of hematologic and plasma biochemical tests performed on dogs of 2 common breeds.

Design: Prospective cohort study.

Animals: 34 Beagles and 44 Labrador Retrievers.

Aging does not influence feeding behavior in cats.

The aim of this investigation was to see whether aging influences feeding behavior in cats. Two studies were carried out. In the first study, a standard canned cat food was fed to six young adult and six senior cats for 10 d on an ad libitum basis.

Role of dietary antioxidants to protect against DNA damage in adult dogs.

We studied the effects of feeding an antioxidant blend of vitamins, minerals and carotenoids to a mixed adult dog population (n = 40, mean 4.4 +/- 1.85 y) for a 16-wk period.

Supplemental vitamin C appears to slow racing greyhounds.

During strenuous exercise, markers of oxidation increase and antioxidant capacity decreases. Antioxidants such as vitamin C may combat this oxidation stress. The benefits of vitamin C to greyhounds undertaking intense sprint exercise has not been investigated.

Application of single-cell gel electrophoresis (comet) assay for assessing levels of DNA damage in canine and feline leukocytes.

Increasing evidence suggests involvement of free-radical species in the development of oxidative DNA damage, the consequences of which have been implicated in a number of degenerative disorders associated with the aging process. Here we report the application of a single-cell gel electrophoresis (comet) assay for assessing levels of DNA damage in canine and feline leukocytes. Leukocytes were collected from 24 healthy adult cats and dogs and subjected to DNA damage ex vivo by exposure to a range of hydrogen peroxide (H(2)O(2)) concentrations (0-250 micromol/L).

Living fast, dying when? The link between aging and energetics.

The idea that aging should be linked to energy expenditure has a long history that can be traced to the late 1800s and the industrial revolution. Machines that are run fast wear out more quickly, so the notion was born that humans and animals might experience similar fates: the faster they live (expressed as greater energy expenditure), the sooner they die. Evidence supporting the "rate-of-living" theory was gleaned from the scaling of resting metabolism and life span as functions of body mass.