No abstract

Potent and simultaneous activation of the two redox systems strongly indicates a definite role of free radicals from XO in the overspill of the acute proinflammatory reaction of the shock syndrome, followed by a significant downregulation.

Abstract-Gestational hypertension during the third trimester reflects an exaggerated maternal inflammatory response to pregnancy. We hypothesized that oxidative stress present even in normal pregnancy becomes uncompensated in hypertensive patients. A glucose-6-phosphate dehydrogenase (G6PD) activity sufficient to meet the increased reductive equivalent need of the cells is indispensable for defense against oxidative stress. The erythrocyte glutathione redox system was studied, where G6PD is the only NADPH source. The glutathione (GSH) redox status was measured both in vivo and after an in vitro oxidative challenge in pregnant women with gestational hypertension (n ϭ 19) vs. normotensive pregnant subjects (n ϭ 18) and controls (n ϭ 20). An erythrocyte GSH depletion with an increase in the oxidized form (GSSG) resulted in an elevated ratio GSSG/GSH (0.305 Ϯ 0.057; mean Ϯ SD) in hypertensive pregnant women vs. normotensive pregnant or control subjects (0.154 Ϯ 0.025; 0.168 Ϯ 0.073; p Ͻ .001). In hypertensive pregnant patients, a "GSH stability" decrease after an in vitro oxidative challenge suggested a reduced GSH recycling capacity resulting from an insufficient NADPH supply. The erythrocyte GSSG/GSH ratio may serve as an early and sensitive parameter of the oxidative imbalance and a relevant target for future clinical trials to control the effects of antioxidant treatment in women at increased risk of the pre-eclampsia syndrome.

Objective: Determination of the surface tension (ST), the total glutathione (GL) content and the ratio of oxidized glutathione (GSSG) to reduced glutathione (GSH) in the tracheal aspirate (TA) of newborn infants with IRDS. Methods: The ST of the TA was determined by monitoring the fluid level pulsated in a capillary glass tube by means of a digitalized videocomputerized picture analysis program, a technique developed in our laboratory. The concentrations of GSSG and total GL in the TA were determined enzymatically with glutathione reductase. All results of laboratory tests were referred to the total phospholipid (PL) concentration. Patients, Experimental Material: TA samples were collected from 32 intubated premature and newborn infants admitted to the NICU with IRDS during the first 2 weeks of their lives. Control samples were obtained from 11 children prior to elective surgery. Results: The ST relative to the PL content (surface tension index, ST_I) was significantly lower in the newborns with IRDS than in the control group, and the concentration of GSH in the TA was also markedly decreased in all IRDS infants studied. The concentration of GSSG and the ratio of GSSG to GSH were significantly higher in the severe cases and in those with an unfavourable prognosis. Surfactant treatment had a protective effect against oxidative stress, it induced a decrease in both the GSSG concentration and in the GL redox ratio (GSSG/GSH) in the TA. There was a close correlation between the GSH content and the ST_I value of the samples studied. Conclusion: Oxidation and consequent depletion of GSH in the TA may be an aggravating factor in the development of the insufficient surface activity in intubated newborns with IRDS.

Acute, bilateral pneumothorax (PT) was produced in 14 newborn piglets. The clinical status of the operated and 14 control animals was monitored by measuring the arterial blood gases, acid-base balance and mean arterial blood pressure. Different brain regions were processed for electron microscopy and albumin immunohistochemistry; water and electrolyte contents were also determined at the end stage of experimental intervention. Electron microscopy showed more intense pinocytotic activity in the endothelium of brain capillaries from PT animals evaluated by morphometry. Statistically significant (p < 0.01) differences were found in the distribution of pinocytotic vesicles in different brain areas of PT animals. The blood-brain barrier seemed to be impermeable to albumin in all brain regions both in the controls and in the PT group. Parallel with the changes observed in pinocytosis, the water and sodium contents were also increased in the PT group in the parietal cortex (water content 85.18 ± SD 0.81% vs. 84.10 ± SD 0.52%, p < 0.01; sodium content in wet brain tissue 70.94 ± SD 8.44 mmol/kg vs. 65.09 ± SD 4.43 mmol/kg, p < 0.05, in dry brain tissue 481.70 ± 75.70 mmol/kg vs. 410.15 ± SD 35.45 mmol/kg, p < 0.05) and in the cerebellum (water content 83.95 ± SD 1.08% vs. 83.02 ± SD 0.89%, p < 0.05; sodium content in wet brain tissue 60.67 ± SD 3.16 mmol/kg vs. 55.90 ± 6.26 mmol/kg, p < 0.01). However, in other brain regions – especially in the water-shed area – there was no correlation between the changes of pinocytosis and water-electrolyte contents of the tissues. It is suggested that the type of edema developing in this severe cardiovascular/hypoxic collapse is cytotoxic of origin and this fact should be more seriously taken into account in the treatment of the disease.