Determinations of erythrocyte enzyme scavengers of oxygen radicals (glutathione-peroxidase, superoxide-dismutase and catalase) and determinations of erythrocyte age-dependent glycolytic activities (glucose-6-phosphate-dehydrogenase, pyruvate-kinase and glucose-phosphate-isomerase) were carried out in cord blood and in the blood taken on the 4th day of life in 152 newborn infants with different peak bilirubin levels. The enzyme activities scavenging oxygen radicals, glutathione-peroxidase and superoxide-dismutase were significantly lower in infants with peak bilirubinemia higher than 214 mumol/l, compared to less-jaundiced neonates, both at birth and on the 4th day of life; their values correlated negatively with peak bilirubinemia at birth and on the 4th day of life. Glycolytic age-dependent enzyme activities were significantly higher in more jaundiced newborn infants only on the 4th day of life, when their values correlated positively with peak bilirubinemia. The results of this investigation suggest that a deficiency of factors protecting from oxygen toxicity, may play a role in the development of neonatal hemolysis and jaundice.
The hypothalamo-pituitary-adrenal (HPA) axis is modulated by sex hormones. Few data exist on the relation between acute estrogen deficit and HPA axis response to corticotropin-releasing hormone (CRH).The effects of a sudden drop in estradiol levels on basal and CRH-stimulated levels of ACTH, cortisol, testosterone, androstenedione and 17-hydroxyprogesterone (17-OHP) were assessed in nine premenopausal women (44-48 years of age), before and after ovariectomy. The CRH test was performed before and 8 days after ovariectomy.A significant reduction in ACTH and adrenal steroids but not in cortisol response to CRH was observed after ovariectomy.The ratio of Dmax androstenedione/17-OHP after CRH stimulation was substantially the same before and after ovariectomy, whereas Dmax 17-OHP/cortisol was significantly lower in ovariectomized women showing increased 21-and 11b-hydroxylase activity. The results show that the acute estrogen deficit induces changes in the HPA axis characterized by reduced stimulated secretion of ACTH and steroids but normal stimulated cortisol production.
ABSTRACT. In an attempt to clarify the mechanism by which the red cells (RBC) of newborn infants are protected against oxidative agents, electron spin resonance (ESR) assays were carried out using the nitroxide radical 4-maleimide-2,2,6,6-tetramethylpiperidinyl-1-01 (Mald), a sulfydryl-reacting agent. The ESR assays were performed in 24 samples of cord blood, 20 samples of blood from 4-day-old infants, and eight samples of &h-old infants. The analyses were carried out on whole blood and washed erythrocytes were resuspended in buffered saline. The same experiments were performed in 10 blood samples from healthy adults as controls. Whole blood, before and after removing the buffy coat, and cell-free plasma were also examined by ESR assay. Cell-free plasma and buffy coats proved not to be appreciably involved in the Ma14 behavior. The data of the ESR spectroscopy demonstrated a significantly slower reaction rate in the samples of cord blood and in blood of 8-h-old infants, compared to that of 4-day-old infants and adults. No significant differences in Mal-6 behavior could be detected between cord blood and 4-day-old infant blood in the results of ESR assays performed in washed red cells. Chemical determination of RBC-reacting sulfydryl groups and the assays of glutathione also demonstrated the absence of differences between cord blood and blood of 4-day-old infants. The results of our investigation suggest that the RBC-sulfydryl-reacting groups are less involved in the detoxification of oxidative agents during the first hours of life than in the following days. This peculiarity of RBC of younger infants appears to be due, to a considerable extent, to the modulation by plasma factors of the interactions between Mal-6 and RBCreacting sulfydryl groups. Therefore, the changes in plasma components occurring during the first hours of life appear to modify the interactions between the RBC and the oxidative agents. (Pediatr Res 24: 391-395, 1988) Abbreviations RBC, red blood cells ESR, electron spin resonance -SH, sulfydryl-reacting groups Mal-6,4-maleimide-2,2,6,6-tetramethylpiperidiny1-1-oxy1 Htc, hematocrit GSH, glutathione
::Children's Hospital U n i v e r s i t y o f Heidelberg, FRG This review focusses on a l t e r a t i o n s o f rheological properties o f bloo which might c o n t r i b u t e t o the development o f c i r c u l a r o t y d e t e r i o r a t i o l i n neonatal septicaemia. The f o l l o w i n g a1 t e r a t i o n s i n rheological properties have been shown i n septicaemia: 1. Decrease i n RBC deform a b i l i t y . RBC d e f o r m a b i l i t y i s determined by the shape and geometry ( i n p a r t i c u l a r , by the excess surface area) and by membrane and cytoplasma properties. W e have shown t h a t i n severe neonatal septicaemia RBC may l o s e membrane as we1 1 as c e l l water. This r e s u l t s i n decreased excess membrane surface and increased i n t e r n a l v i s c o s i t y . Moreover, endotoxin may markedly decrease RBC deformabili t y i n v i t r o and i n v ivo. This appears t o be due t o a l o s s i n membrane e l a s t i c i t y . A decrease i n RBC d e f o r m a b i l i t y may a l s o occur i n n e c r o t i z i n g e n t e r o c o l it i s as a r e s u l t o f e i t h e r endotoxin-mediated membrane destruction o r neuraminidase-induced l o s s o f membrane charge. 2. Increase i n RBC aggregation. RBC aggregation i s p r i n c i p a l l y caused by plasma macromolecules (e.g., f i b r i n o g e n ) . I n neonatal septicaemia, plasma f i b r inogen may increase. Moreover, i n neonates w i t h septicaemia RBC aggreg a t i o n i s more enhanced than expected from the r i s e i n plasma f i b r inogen. We have shown t h a t fibrin-monomer-f i b r i n o g e n complexes induce a marked r i s e i n RBC aggregation i n both neonatal and a d u l t blood. Since the complexes are formed as a r e s u l t o f endotoxinaemia, they might c o n t r i b u t e t o the increase i n RBC aggregation i n neonatal s e p t i -/ caenia . These data i n d i c a t e t h a t a1 tered rheological blood properties may c o n t r i b u t e t o c i r c u l a t o r y compromise i n septicaemia. RHEOLOGICAL PROPERTIES OF ERYTHROCYTES IN PATIENTS WITH286 CONGENITAL DYSERYTHROPOETIC ANEMIA 11.
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