Effects of antioxidants and haemoglobin status on the t-butyl hydroperoxide-induced oxygen uptake by red blood cells

Oxygen uptake by erythrocytes exposed to t-butyl hydroperoxide (t-BHP) exhibited an induction period. The rate of oxygen consumption can be reduced by antioxidants and blood plasma. The induction time was not appreciably modified by the antioxidants tested, however, plasma increased it by a factor of two. The in vivo pretreatment with diethyl maleate (0.6 g kg-1) produced increased rates of oxygen uptake without changes in the induction period, while vitamin E (12.5 mg kg-1) elicited lower oxygen consumption rates and longer induction times, compared to those observed in cells from control rats upon addition of the hydroperoxide. These results suggest that the antioxidants tested on the t-BHP lipid peroxidation in erythrocyte suspensions act as inhibitors and/or retarders of the process. Furthermore, lipid peroxidation induced in these conditions seems to depend upon the haemoglobin status of the cells as oxygen uptake, malondialdehyde production and chemiluminescence were significantly higher in methaemoglobin-containing cells than in those containing oxyhaemoglobin.

Superoxide radical generation, NADPH oxidase activity, and cytochrome P-450 content of rat liver microsomal fractions in an experimental hyperthyroid state: relation to lipid peroxidation

The effect of thyroid hormone treatment on hepatic microsomal functions related to NADPH-dependent electron transfer reactions was studied in rats given 0.1 mg T3/kg BW for 1, 2, 3, and 7 consecutive days. This treatment resulted in increased rates of O2-. generation by microsomal fractions, concomitantly with an enhancement in NADPH oxidase activity and decreased cytochrome P-450 content, in livers exhibiting increased respiration. Subsequent studies showed elevated levels of malondialdehyde in microsomal fractions and liver homogenates, as well as augmented chemiluminescent response in the latter system. These results indicate that the calorigenic effect of T3 on the liver tissue is accompanied by a stimulation of microsomal functions involving univalent reduction of oxygen. This cellular response might lead to a greater lipid peroxidative rate and cytochrome P-450 loss as secondary events of thyroid hormone action.

Differential lipid peroxidative response of rat liver and lung tissues to glutathione depletion induced in vivo by diethyl maleate: effect of the antioxidant flavonoid (+)-cyanidanol-3

The administration of a single dose of diethyl maleate (DEM) to fed rats elicited a drastic decrease in the content of reduced glutathione (GSH) both in liver and lung tissues after 6 h of treatment. Cellular GSH depletion induced by DEM was accompanied by a marked increase in pulmonary lipid peroxidation which was completely abolished by (+)-cyanidanol-3, without changes in the liver. Superoxide dismutase (SOD) activity remained unchanged in both tissues in this situation. Hepatic and pulmonary GSH depletion induced by a second dose of DEM given 24 h later produced a further increase in lung lipid peroxidation and a diminution of pulmonary SOD activity. In this condition, hepatic lipid peroxidation and SOD activity were not altered. These results indicate that lung and liver tissues exhibit a different lipid peroxidative response to chemically-induced GSH depletion.

Time course study of the changes in blood glutathione induced by acute ethanol intoxication in the rat

Acute ethanol treatment of rats (5 g/kg) has a biphasic effect on the glutathione content of the erythrocyte. After 3 h of intoxication there is a diminution in total GSH equivalents, followed by a recovery to basal values 6 h after treatment. The decrease of total GSH equivalents is mainly due to a diminution of the oxidized form of the tripeptide. Concomitantly a marked increase in the plasma level of glutathione was found at 3 h, followed by a diminution to values obtained at time zero.

Observations on the early mechanisms of severed nerve regeneration after compressive tubulation repair

A moderately compressive tubulation procedure has been devised to improve regeneration that follows fascicular neurorrhaphy. The early phases of the regenerative process were analyzed to identify the underlying cellular mechanisms. Adult Sprague-Dawley rats were subjected to bilateral fascicular neurorrhaphy involving tubulation on one side with a dura mater sheet closely apposed to the suture site. One to 16 days postoperatively the nerves were processed for histological analysis. Compared with nontubulated nerves, the cuffed side displayed a longer extent of retrograde myelin and axonal degeneration, a faster rate of orthograde remyelination, axonal invasion of the suture plane at about the same period (fifth postoperative day), larger contingent of regenerating fibers invading the distal stump, more longitudinally oriented fibers at the repair level, no escape of regenerating fibers into the extraneural tissue through the repair borders, and less intraneural edema. These findings have implications for the potentially beneficial effects of mechanically restricting post-traumatic intraneural edema buildup during nerve regeneration.

A model of neocortical histogenesis based on Cajal's principles of homotropism and neurocladism

Generation and regeneration of the Nervous System are considered essentially similar processes since the pioneering studies of Cajal (15). The present paper is a hypothetical attempt to explain the puzzling internal-to-external histogenetic pattern of the mammalian neocortex(4), largely on the basis of various observations made by Cajal on the developing and regenerating Central and Peripheral Nervous System. Fundamental to our model are the principles of excitatory neurocladism and of reciprocal homotropism as described by Cajal. By assuming that both latter principles are valid for the early stages of neocortical development, an explanation can be given for most of the main events of neocortical histogenesis that is consistent with known facts. Our main conclusion is that neocortical neurogenesis differs from that of any other area of the neural tube due to the interposition of the corticipetal fiber system in between the cortical matrix layer and the cortical plate. The mechanical obstacle thus posed to neuroblast migration by this fiber system appears responsible - by activating the operation of the aforementioned principles of Cajal - for both the cellular and topographical neurogenetic sequences of neocortical development, as well as the growth predominantly in width, all features that are unique to the neocortex as compared to the rest of the neural tube.

Visuo-limbic interactions. Evidence for a pathway from the pulvinar to the cingulate cortex

Synaptic-terminal degeneration was analyzed in 18 specimens of Octodon degus after stereotaxic lesions in the pulvinar nucleus. Aside from the cortical targets of the pulvinar (Kuljis et al. 1979), a conspicuous projection towards the nucleus lateralis dorsalis of the thalamus (LD) was observed. The LD is known to receive fibers from the fornix (Valenstein and Nauta 1959), and to project heavily over the cingulate cortex (Locke et al. 1964; Ajmone Marsan 1965; Graybiel 1974); we have confirmed the latter projection in 3 operated specimens of Octodon degus. The possibility is discussed, in the light of these findings, that the pulvino-LD pathway may be important for the purposes of visuo-limbic interactions.

Artificial induction of twinning in cattle by means of supplemental embryo transfer

The induction of twins by surgical and nonsurgical transfer was performed 6 - 8 days after Artificial Insemination (A.I.) in a total of 142 cows. Of the 47 heifers, which received surgically transferred embryos, 32 (68%) became pregnant. Of the 95 cows, which received nonsurgically transferred embryos, 58 (61,6%) became pregnant. A total of 90 (63.5%) of the recipient animals became pregnant. Up to date 64 recipients have calved; twins have resulted in 40 and 48,2% resp, from surgical and nonsurgical inductions. Out of a total of 64 calvings 29 (45,3%) were twins, and of these 38% were males, 27% were females, and 34% were mixed births. Female - calves resulted in freemartinism. There was no increase in the incidence of either retained placenta or dystocia. The induction of twinning by means of embryo transfer can be regarded as a useful method for the increase in the reproductive performance cattle.

Effect of acute and chronic ethanol ingestion on the content of reduced glutathione of various tissues of the rat

The effect of acute ethanol ingestion (5 g/kg) by fasted rats, or chronic treatment in fed animals, revealed a significant decrease in the content of reduced glutathione of the liver and kidney. No changes were observed in reduced glutathione levels of the pancreas, stomach or spleen in the acute model. In this condition, the time course study of the decrease in reduced glutathione levels showed a progressive effect in the liver and a rapid and constant effect in the kidney.

Effect of (+)-cyanidanol-3 on the changes in liver glutathione content and lipoperoxidation induced by acute ethanol administration in the rat

Acute ethanol administration to rats fasted overnight resulted in a significant decrease in the content of glutathione (GSH) of the liver concomitantly with a partial increase in oxidized glutathione levels, representing a net 38% decrease in total GSH equivalents. In these conditions, liver lipoperoxidation is significantly enhanced. Treatment with (+)-cyanidanol-3 prior to ethanol ingestion was able to reduce by 80% the ethanol-induced depletion in total GSH equivalents and to completely abolish lipoperoxidation. These results indicate that (+)-cyanidanol-3 has a protective effect on the changes in liver GSH levels and lipoperoxidation induced by ethanol, probably related to its scavenging action exerted on free radicals.

Autoradiographic study of the development of the neostriatum in the rabbit

Autoradiographic labelling has been employed to analyze the morphogenesis of the neostriatum. Pregnant rabbits received a single intraperitoneal injection of tritiated thymidine at different stages of gestation. Careful microscopical observation of the autoradiographs shows that cellular components of the neostriatum originate between days 15 and 18 of the intrauterine life from a layer of proliferating matrix cells that lies on the floor of the anterior part of the lateral ventrical (ganglionic eminence). From this proliferating layer, precursor cells migrate outwards to reach the developing neostriatum in a sequential fashion according to two gradients of histogenesis. Thus, it was found that neurons formed at early stages occupy a ventromedial position in the neostriatum, while those formed at later stages occupy a dorsolateral position (ventromedial to dorsolateral gradient). Furthermore, the present study indicates that the rostral regions of the neostriatum arise somewhat later than the caudal ones, demonstrating the existence of a caudocephalic gradient of cytogenesis.