Delayed expression of NADPH-diaphorase in rat brain after administration of the cholinotoxin AF64A

Administration of cholinotoxin etylcholine aziridinium (AF64A) into the brain selectively induces nonrever-sible cholinergic deficit. Wistar rats were injected intracerebroventricularly bilaterally with AF64A at doses of 1–3 nmol/ventricle. 28 days later the number of neurons survived was counted in dorsolateral, intermediate and medial groups of cells of the medial septum. AF64A induced a decrease in neuronal density and expression of cholineacetyl transferase at all doses used as well as in all regions studied. Brain sections were also stained for NADPH-diaphorase representing neuronal NO-synthase. Effects of AF64A on NADPH-diaphorase expression depended on the region studied. The number of NADPH-diaphorase-positive cells increased in the medial cellular group where more cholineacetly transferase-positive cells survived. In contrast, decrease in NADPH-diaphorase expression in the dorsolateral group of cells coincided with low level of cholineacetyltransferase-po-sitive neurons. The data presented suggest that in the AF64A-dependent model of neurodegeneration NO may play a neuroprotective function.     

Disturbance of systemic antioxidant profile in nonsmall cell lung carcinoma.

The present study aimed to determine the alterations of antioxidant activities in erythrocytes from patients with nonsmall cell lung carcinoma (NSCLC). A comparative study of the systemic antioxidant activities in red blood cell lysate from subjects with NSCLC and healthy control subjects was conducted. The antioxidants catalase, superoxide dismutase (SOD) and glutathione peroxidase (GPx) were measured using chemical kinetic reactions under spectrophotometry. In total, 189 cases of mostly advanced-stage IIIB or stage IV NSCLC and 202 healthy controls were studied. In subjects with lung cancer, there was similar catalase activity, lower SOD activity (median (interquartile range) 13.4 (9.0-27.2) versus 48.7 (27.0-64.3) U x (ghaemoglobulin(Hb)(-1)), and higher GPx activity (175.2 (126.6-288.3) versus 49.2 (39.5-59.2) mU x (gHb)(-1)) compared with controls. The antioxidant activities in lung cancer subjects were not associated with age, sex, smoking status, or tumour cell types. However, more advanced disease (stage IV compared with stage IIIB) was associated with lower SOD activity. Using multivariable analysis, the presence of lung cancer independently predicted SOD and GPx activities. In conclusion, nonsmall cell lung carcinoma in Chinese subjects is associated with alterations in systemic antioxidant activities, which may play an important role in carcinogenesis.     

Age-dependent Responses to Thermal Hyperalgesia and Mechanical Allodynia in a Rat Model of Acute Postoperative Pain

Background: Developmental differences in short- and long-term responses to pain, especially surgical pain, have received minimal attention. The purpose of the present study was to examine postoperative responses in rats of developmental ages paralleling the infant to young adult human.

Methods: The withdrawal threshold to von Frey filament testing and withdrawal latency to hind-paw radiant heating were determined before and for various times after hind-paw incision in rats 2, 4, and 16 weeks of age. Control rats of these ages were observed serially without surgery.

Results: In control animals, younger rats were more sensitive to mechanical stimulation and less sensitive to thermal stimulation. Paw incision resulted in similar changes to both types of stimulation in all age groups, peaking 4 h after surgery. However, the return to normal sensitivity to mechanical stimulation, as measured by return of threshold to 80% of normal, occurred more quickly in 2-week-old than in 4- and 16-week-old animals. In contrast, there was no age difference for time to return to normal sensitivity to thermal stimulation after surgery.     

On the road to automatic: dynamic aspects in the development of expertise.

One of the important steps on the road to becoming expert in a motor skill occurs when the individual can perform the movements in a seemingly effortless and automatic fashion. The authors review two lines of investigations, namely, fMRI and mathematically guided studies of the dynamics of skill acquisition, that suggest that this road to automatic involves two steps: (1) an increasing reliance on the self-regulatory aspects of the motor task, and (2) a minimization of the role of mechanisms based on intentionally directed corrective movements. The interplay between these two mechanisms implies that, at a given skill level, performance decreases whenever intention intervenes. The observation that psychological factors may be as important as mechanical repetition for the development of expertise has important implications for the design of neurorehabilitative strategies.