Changes in the activity of plasma beta-endorphin-like-immunoreactivity induced by transcutaneous stimulation of the brain

A newly devised technique of electrical transcutaneous brain stimulation has been applied to a population of cephalalgic patients in order to assess its proficiency in pain relieving and in increasing the concentration of serum endorphins. A significant pain relief associated with an increase in serum endorphins has been obtained only in those patients in which clinical and instrumental evaluations had identified the headache as one of "organic" origin. By contrast both in "non organic" and in control subjects the technique has proved to be effectiveless. Our results suggest that transcutaneous electrical brain stimulation can affect the release of endogenous opioids relieving pain at least in selected patients.     

Longitudinal impact of physical activity on lipid profiles in middle-aged adults: the Atherosclerosis Risk in Communities Study

Evidence exists that increased levels of physical activity decrease the population burden of cardiovascular disease (CVD). Although risk factors for CVD, including plasma lipids and lipoproteins, have been associated with physical activity, studies including a sizeable number of minority participants are lacking. Our purpose was to interrogate the longitudinal effect of physical activity on plasma lipids and lipoproteins in the African American and white participants of the Atherosclerosis Risk in Communities (ARIC) Study. Nine years of follow-up data on 8,764 individuals aged 45–64 years at baseline were used in linear mixed-effects models to estimate the association between increases in baseline physical activity on mean change in HDL, LDL, total cholesterol, and triglyceride levels. Increases in the level of activity were associated with increases in HDL in all strata and decreases in triglycerides among white participants. Physical activity was associated with LDL in all women, while the association with total cholesterol was limited to African American women. This study is one of the few to investigate the effect of physical activity on lipids and lipoproteins in a race- and sex-specific manner. Overall our results highlight the importance of physical activity on plasma lipid profiles and provide evidence for novel differential associations.     

Nitric oxide reduces the thermogenic changes induced by lateral hypothalamic lesion

The experiment described here tests the effect of intracerebroventricular (icv) injection of nitric oxide (NO) precursors, such as L-arginine (L-arg) and nitroprusside (NP), on the thermogenic changes induced by lesion of the lateral hypothalamus (LH). The firing rate of the nerves innervating interscapular brown adipose tissue (IBAT), along with IBAT and colonic temperatures (T_IBAT and T_C) were monitored in urethane-anesthetized male Sprague-Dowley rats lesioned in the LH. These variables were measured before and after and icv injection of 4 μmol L-arg or 400 nmol NP. The same variables were also monitored in: a) lesioned rats with icv administration of saline; b) sham-lesioned animals with icv injection of L-arg or NP; c) sham-lesioned rats with icv injection of saline. The results show that L-arg or NP injection reduces the increases in firing rate, T_IBAT, and T_C induced by LH lesion. These findings suggest that NO plays a key role in the thermogenic changes following LH lesion.     

Performance evaluation of a high-speed inertial exercise trainer

A high-speed, low-resistance inertial exercise trainer (IET, Impulse Training Systems, Newnan, Ga) is increasingly employed in rehabilitative and athletic performance settings. Repetitions on an IET are done through a large range of motion because multijoint movements occur over more than one plane of motion, with no limitation on velocities or accelerations attained. The current study purpose is to assess data reproducibility from an instrumented IET through multiple test-retest measures. Data collection methods required the IET left and right halves to be fitted with a TLL-2K force transducer (Transducer Techniques, Temecula, Calif) on one of its pulleys, and an infrared position sensor (Model CX3-AP-1A, automationdirect.com) located midway on the underside of each track. Signals passed through DI-158U signal conditioners (DATAQ Instruments, Akron, Ohio) and were measured with a four-channel analog data acquisition card at 4000 Hz. To assess data reproducibility, college-age subjects (n = 45) performed four IET workouts that were spaced 1 week apart. Workouts entailed two 60-second sets of repetitive knee- and hip-extensor muscle actions as subjects were instructed to exert maximal voluntary effort. Results from multiple test-retest measures show that the IET elicited reproducible intra- and interworkout data despite the unique challenge of multiplanar and multijoint exercise done over a large range of motion. We conclude that future studies in which IET performance measurement is required may choose to instrument the device with current methodology. Current practical applications include making IET data easier to comprehend for the coaches, athletes, and health care providers who use the device.     

Stand structure and regeneration of <Emphasis Type="Italic">Populus euphratica</Emphasis> forest in the lower reaches of the Heihe River,NW China

Populus euphratica Oliv. is a main tree species that forms natural riparian forests in arid and semi-arid areas from Morocco to the Ordos Plateau. This study is designed to clarify the forest structure and dynamics of P. euphratica and to elucidate the ecological mechanisms sustaining riparian forests under unreliable environmental conditions. This study was conducted in a P. euphratica forest of the Ejina Oasis in Inner Mongolia, China, which is a hyperarid area. According to their tree size distribution, P. euphratica forests can be grouped into juvenile, mature, and overmatured stages. Almost all large P. euphratica showed dieback. The regeneration density on the forest floor shows a relation with the degree of height decrease due to dieback damage, as evaluated using the ratio of actual height to the maximum height estimated from the D–H relation. Therefore, after the mature stage, individual trees continue to grow while controlling their canopy size to adjust to changing environmental conditions in the overmatured stage. Our results suggest that P. euphratica growing under large fluctuations in groundwater levels exhibit a sophisticated regeneration system with canopy degradation.     

Partial cloning and expression of mRNA coding choline acetyltransferase in the spinal cord of the goldfish, Carassius auratus

Choline acetyltransferase (ChAT, EC 2.3.1.6) synthesizes a neurotransmitter, acetylcholine in cholinergic neurons. ChAT is considered to be the most specific marker for cholinergic neurons. To obtain a better marker of the neurons, as the first step, we isolated a partial ChAT cDNA from the goldfish (Carassius auratus) brain by RT-PCR methods. The partial cDNA of the goldfish ChAT was composed of 718 nucleotides. The amino acid sequence of the goldfish ChAT is approximately 70% identical to those of mammalian and chicken ChAT. Northern blot analysis demonstrated that ChAT mRNA was expressed in the brain and the spinal cord of the goldfish, and much abundant in the spinal cord. In the spinal cord of the goldfish, ChAT-positive neurons were detected mainly in the ventral horn by in situ hybridization. In addition, fluorescence in situ hybridization combined with a retrograde labeling by using True Blue demonstrated ChAT mRNA positive neurons were exactly motoneurons. In the cord, putative presynaptic sympathetic neurons were also labeled.