Effect of a high-intensity exercise training on the metabolism and function of macrophages and lymphocytes of walker 256 tumor bearing rats.

Epidemiologic studies suggest that moderately intense training promotes augmented immune function, whereas strenuous exercise can cause immunosupression. Because the combat of cancer requires high immune function, high-intensity exercise could negatively affect the host organism; however, despite the epidemiologic data, there is a lack of experimental evidence to show that high-intensity training is harmful to the immune system. Therefore, we tested the influence of high-intensity treadmill training (10 weeks, 5 days/week, 30 mins/day, 85% VO(2)max) on immune system function and tumor development in Walker 256 tumor-bearing Wistar rats.

Expression of connexins 36, 43, and 45 during postnatal development of the mouse retina.

Gap junction channels formed by connexins (Cx) may play essential roles in some processes that occur during retinal development, such as apoptosis and calcium wave spread. The present study was undertaken to determine the distribution pattern of Cx36, Cx43, and Cx45 by immunofluorescence, as well as their gene expression levels by quantitative PCR during postnatal development of the mouse retina. Our results showed an increased expression of neuronal Cx36 from P1 until P10, when this Cx reached adult levels, and it was mainly distributed in the outer and inner plexiform layers.

Light-Induced photoreceptor degeneration in the mouse involves activation of the small GTPase Rac1.

Purpose: Rho GTPases play a central role in actin-based cytoskeleton reorganization, and they participate in signaling pathways that regulate gene transcription, cell cycle entry, and cell survival. This study verifies the role of Rac1 during light-induced retinal degeneration.

Methods: BALB/c mice were exposed to degenerative light stimulus, and their eyes were enucleated immediately or after the mice were kept in the dark for 6, 24, and 48 hours.

Small GTP-binding protein RhoB is expressed in glial Müller cells in the vertebrate retina.

Among several small Rho GTPases observed in the chick retina, RhoB was transiently expressed during development and mainly present in glial Müller cells in the adult. The aim of this study was to compare the distribution of RhoB in the chick and mouse adult retinas and to study its potential role in the maintenance of cell morphology. The distribution of RhoB was studied in situ and pure Müller cell cultures were submitted to Clostridium difficile toxin A and lysophosphatidic acid (LPA) treatment in order to inactivate and activate Rho proteins, respectively.

Rat myocellular and perimysial intramuscular triacylglycerol: a histological approach.

Purpose: There is controversy as to the use of intramuscular triacylglycerol (IMTAG) during exercise and to whether endurance training increases its utilization, despite the various methodologies used to address these questions. We used a histological-morphometrical approach to study the relative contribution of the two compartments of IMTAG storage, intramyocellular, and perimysial adipocytes, during exercise in sedentary and endurance-trained rats.

Methods: After osmium impregnation, the soleus (SOL) and gastrocnemius (GAS) were studied under light and electron microscopy.