Effect of concussive head injury on central catecholamine levels and synthesis rates in rat brain regions.

—Unanesthetized male Sprague-Dawley rats were subjected to head injury using a unique acceleration-deceleration model designed to mimic the most prevalent form of clinical head injury. Endogenous tyrosine, dopamine and norepinephrine were determined fluorometrically and catecholamine synthesis rates were determined by a radioisotopic method. These values were determined in four brain regions: cortex-striatum, midbrain-hypothalamus, medulla-pons, and cerebellum, and were performed at 5 min, 15 min, 1 h, and 2h post-trauma. Dopamine levels were elevated in the medulla pons region at 5 min after trauma and in the midbrain-hypothalamus at the 15 min and 1 h time periods. This increase in dopamine levels may reflect disruption of dopamine beta hydroxylase activity. Norepinephrine synthesis rate in the cerebellum was elevated at 2 h after trauma. Changes in the other parameters were observed but appeared to be related to stress, and the effect of stress in this model is discussed.     

Physiological control of brain norepinephrine synthesis by brain tyrosine concentration

The intraperitoneal administration of tyrosine to rats causes proportional increases in brain tyrosine levels and in the accumulation of the norepinephrine metabolite 3-methoxy-4-hydroxy-phenylethyleneglycol-sulfate (MOPEG-SO₄) after probenecid. Brain tyrosine level after tyrosine administration or after the consumption of a single meal is also positively correlated with brain MOPEG-SO₄ accumulation in rats that do not receive probenecid but are subjected to cold stress. These observations extend our earlier finding that brain tyrosine level can affect the rates at which catecholaminergic neurons synthesize and turn over their transmitters.     

Physiological effects of broccoli consumption

Epidemiological studies suggest that broccoli can decrease risk for cancer. Broccoli contains many bioactives, including vitamins C and E, quercetin and kaempferol glycosides and, like other members of the Brassicaceae, several glucosinolates, including glucobrassicin (3-indolylmethyl glucosinolate) and glucoraphanin (4-methylsulphinylbutyl glucosinolate). A key bioactive component responsible for much of this activity may be sulforaphane (1-isothiocyanato-4-methylsulfinylbutane), a hydrolysis product of glucoraphanin. Sulforaphane not only upregulates a number of phase II detoxification enzymes involved in clearance of chemical carcinogens and reactive oxygen species, but has anti-tumorigenic properties, causing cell cycle arrest and apoptosis of cancer cells. The bioequivalency of sulforaphane and whole broccoli have not been fully evaluated, leaving it unclear whether whole broccoli provides a similar effect to purified sulforaphane, or whether the presence of other components in broccoli, such as indole-3-carbinol from glucobrassicin, is an added health benefit. Dietary indole-3-carbinol is known to alter estrogen metabolism, to cause cell cycle arrest and apoptosis of cancer cells and, in animals, to decrease risk for breast cancer. Recent research suggests that both dietary broccoli and the individual components sulforaphane and indole-3-carbinol may offer protection from a far broader array of diseases than cancer, including cardiovascular and neurodegenerative diseases. A common link between these oxidative degenerative diseases and cancer may be aggravation by inflammation. A small body of literature is forming suggesting that both indole-3-carbinol and sulforaphane may protect against inflammation, inhibiting cytokine production. It remains to be seen whether cancer, cardiovascular disease, dementia and other diseases of aging can all benefit from a diet rich in broccoli and other crucifers.     

Vitamin E reduces amyloidosis and improves cognitive function in Tg2576 mice following repetitive concussive brain injury

Traumatic brain injury is a well-recognized environmental risk factor for developing Alzheimer's disease. Repetitive concussive brain injury (RCBI) exacerbates brain lipid peroxidation, accelerates amyloid (Abeta) formation and deposition, as well as cognitive impairments in Tg2576 mice. This study evaluated the effects of vitamin E on these four parameters in Tg2576 mice following RCBI. Eleven-month-old mice were randomized to receive either regular chow or chow-supplemented with vitamin E for 4 weeks, and subjected to RCBI (two injuries, 24 h apart) using a modified controlled cortical impact model of closed head injury. The same dietary regimens were maintained up to 8 weeks post-injury, when the animals were killed for biochemical and immunohistochemical analyses after behavioral evaluation. Vitamin E-treated animals showed a significant increase in brain vitamin E levels and a significant decrease in brain lipid peroxidation levels. After RBCI, compared with the group on regular chow, animals receiving vitamin E did not show the increase in Abeta peptides, and had a significant attenuation of learning deficits. This study suggests that the exacerbation of brain oxidative stress following RCBI plays a mechanistic role in accelerating Alphabeta accumulation and behavioral impairments in the Tg2576 mice.     

Physiological effects of an ultra-marathon run

Autonomic functions of the body and gas exchange have been studied in one athlete (master of sports in skiing, aged 27 years, with a maximal oxygen consumption of 67 mL/(min kg)); during a 6-h indoor ultra-marathon race; at an average speed of 2.7 m/s. Continuous monitoring of the heart rate was carried out using a Polar RS 800 heart rate monitor. Gas analysis of the exhaled air and recording of the parameters of external respiration were carried out during the first hour with subsequent repetitions during 20?C30 minutes each hour, using a Metamax mobile device (Germany) mounted on the subject throughout the race. Before and after the subject passed the intervals of a distance when these parameters were measured, the blood lactate content was measured. Our data demonstrate a number of features that accompany fatigue at the final stage of the race, such as a decrease in efficiency of body functions, which is expressed by an increased heart rate and oxygen usage, an activation of anaerobic glycolysis path of energy production, and intensification of the external respiration. In addition, the methods of correlation and regression analysis revealed the changes (increase and decrease) of the relationship between the functions depending on whether muscular performance is at the stage of warming up, sustainably high performance, or in at a stage of extreme fatigue. These findings suggest interference of the effects of the central and tissue mechanisms of fatigue on the organization of oxygen transportation in the body. Apparently, in the instance of an ultra-marathon run, i.e., a prolonged performance of moderate power, autonomic functions, rather than the energy resources of the body, play the role of the main limiting factor.     

Physiological and developmental effects of colchicine

Colchicine has been a very useful diagnostic tool to determineif a particular developmental process requires cell divisionor microtubules; however, it produces certain side effects whichmay limit its usefulness. Low concentrations depolarize cellenlargement and higher concentrations actually inhibit cellenlargement; the threshold concentration varies depending onthe tissue. 0.2% (w/w) inhibits solute uptake and respirationin corn seedling roots. Higher concentrations also inhibit DNAand ethylene synthesis. Although ethylene and colchicine cause a similar swelling inthe elongation zone of roots, colchicine does not promote ediylenesynthesis and may even inhibit. In addition, the ethylene antagonist,CO₂, does not prevent the depolarization of cell enlargementin corn roots. Thus colchicine induction of swelling in cornroots is not mediated by ethylene. (Received July 3, 1971; )     

Physiological genomic analysis of the brain renin-angiotensin system

The brain renin-angiotensin system (RAS) has long been considered pivotal in cardiovascular regulation and important in the pathogenesis of hypertension and heart failure. However, despite more than 30 years of study, the brain RAS continues to defy explanation. Our lack of understanding of how the brain RAS is organized at the cellular and regional levels has made it difficult to resolve long-sought questions of how ANG II is produced in the brain and the precise mechanisms by which it exerts its actions. A major reason for this is the difficulty in experimentally dissecting the brain RAS at the regional, cellular, and whole organism levels. Recently, we and others developed a series of molecular tools for selective manipulation of the murine brain RAS, in parallel with technologies for integrative analysis of cardiovascular and volume homeostasis in the conscious mouse. This review, based in part on a lecture given in conjunction with the American Physiological Society Young Investigator Award in Regulatory and Integrative Physiology (Water and Electrolyte Homeostasis Section), outlines the physiological genomics strategy that we have taken in an effort to unravel some of the complexities of this system. It also summarizes the principles, progress, and prospects for a better understanding of the brain RAS in health and disease.     

Calcium-activated neutral protease activities in brain trauma

This paper investigates the level of cytosolic and synaptosomal forms of calcium activated neutral protease activities in the normal brain and their changes following a freezing lesion in the rabbit. From 1 to 24 hours post lesion we observe a progressive disappearing of the enzyme activities from the cytosolic compartment and concurrently their increase in the membranal fraction. These changes are likely to be due to a rise in intracellular calcium concentration, a well documented consequence of many cellular insults. The specific role of the activation of calpain activities in the pathophysiology of trauma is discussed, an enhancement of excitotoxic mechanisms is proposed.     

Evaluation of the protective capacity of baseball helmets for concussive impacts

The purpose of this research was to examine how four different types of baseball helmets perform for baseball impacts when performance was measured using variables associated with concussion. A helmeted Hybrid III headform was impacted by a baseball, and linear and rotational acceleration as well as maximum principal strain were measured for each impact condition. The method was successful in distinguishing differences in design characteristics between the baseball helmets. The results indicated that there is a high risk of concussive injury from being hit by a ball regardless of helmet worn.     

Physiological effects of different types of beta-glucan

Background: Numerous types of glucans have been isolated from almost every species of yeast, grain, and fungi. These products have been extensively studied for their immunological and pharmacological effects. Aim: In this paper we evaluated the possibility whether individual glucans will be similarly active against each of the tested biological properties or if each glucan will affect different reactions. Methods: Immunological effects of glucans were measured by evaluation of phagocytosis of HEMA particles by peripheral blood leukocytes and production of IL-2 by mouse splenocytes. Next we measured the effects of long-term treatment with glucan on levels of blood glucose and blood cholesterol. Four different glucans differing in origin (yeast, grain and mushroom) were used. Results: Our results showed that the same glucan, yeast-derived insoluble #300 glucan, stimulated phagocytosis of peripheral blood leukocytes, production of IL-2 by mouse splenocytes, lowered the cholesterol levels in mice with experimentally-induced cholesterolemia and lowered the level of blood sugar after induced hyperglycaemie. The remainder of tested glucans were only marginally active. Conclusion: Taken together, our study showed that with respect to natural glucans, there is a yes-or-no effect suggesting that highly purified and highly active glucans will have pleiotropic impact, whereas poorly isolated and/or less active glucans will have only mediocre biological properties.