In a recent series of studies, we demonstrated that stress in parallel with granulocytosis after birth. It is speculated that tissue damages are induced by free radicals and superoxides, in humans and animals, with resultant sympathetic nerve strain, induces severe granulocytosis, because granulocytes which are mainly produced by granulocytes at that time. [4][5][6][7] Such signs in humans and mice include the elevation of carry adrenergic receptors on the surface. Because activated granulocytes produce free radicals and superoxides, they transaminases, termination of hematopoiesis in the liver, and the formation of fatty liver. sometimes induce tissue damage if the stress is too strong or continuous. Human neonates are also known to show high
We postulated that neonatal granulocytosis is a transient phenomenon following birth and does not appear before levels of granulocytes in the peripheral blood. In this study, we investigated whether such neonatal granulocytosis are a birth. The present study was designed to test our hypothesis, i.e., to determine whether or not the commonly observed stress-associated response at birth. Both human and mouse materials, before and after birth, were used. The number of granulocytosis is, in fact, related to the birth process, and if so, to elucidate possible mechanisms underlying birth-related leukocytes in the blood, as well as some other factors in the serum, were measured. Although levels of granulocytes were granulocytosis. All data from the present study suggest that neonatal granulocytosis is quite similar to stress-associated found to be low in fetal humans and mice, they increased sharply after birth. In parallel with this postpartal granulocy-responses. For example, a transient elevation in serum levels of catecholamines at birth in mice may induce granulocyto-tosis, transaminases in sera increased transiently. In reference to results of a transient elevation in the levels of catecholsis, which carries adrenergic receptors on the surface. If our amines at birth in mice, all these phenomena resemble stresshypothesis is validated, the results may explain why fetal associated responses. Indeed, fatty liver and hematopoietic hematopoiesis suddenly ceases in the liver after birth and destruction in the liver were also observed in mice and huwhy neonates consistently experience jaundice. mans. At this time, the production of inducible nitric oxide synthase (iNOS) by granulocytes in the liver was evident.
MATERIALS AND METHODS
These results suggest that neonatal granulocytosis is a post-
Human Materials. Leukocytes of healthy neonates were obtained partum event which results from various stresses (e.g., oxygen from the cord blood at birth or from the peripheral blood on poststress) at birth. This event may be responsible for such wellpartum days 1, 3, and 7. The number of total leukocytes was first known neonatal phenomena as the termination of fetal hemaenumerated, after which the proportion of granulocytes and lymtopoiesis in the liver and as neonatal jaundice. (HEPATOLOGY phocytes was determined from cell smears stained by the May-1997;26:1567-1572.)
Gru Β¨wald-Giemsa method. Informed consent was obtained from the parents of the babies.
Severe but transient granulocytosis (15 to 20 1 10 3 /mm 3 ) Mouse Materials. Neonatal or fetal BALB/c mice were euthanized is always seen in neonates, and a return to normal granuloby ether anesthesia. Leukocytes were obtained from various organs cyte levels occurs within 3 days. 1-3 However, it is not known at fetal (day 19 of gestation), neonatal (postpartum day 1), and adult (8 week) ages. Non-parenchymal cells in the liver, mainly whether or not this condition exists before birth. In our hematopoietic cells, were obtained by Percoll (35% Percoll conlaboratory, incidental observations in mice led us to suspect taining 100 U/mL of heparin) gradient centrifugation. 8 Briefly, fetal that the granulocytosis seen in neonates may result from liver was pressed through 200-gauge stainless steel mesh and sussome stresses, with the liver suffering the greatest tissue depended in 30 mL of RPMI1640 medium supplemented with 2% struction. In support of this idea, it was found that many newborn calf serum. After being washed once, the suspension was signs of tissue destruction, especially in the liver, are seen overlapped onto the Percoll cushion. The resulting cell pellets con- tained non-parenchymal cells.
Lung leukocytes were obtained by cutting the lung into small pieces and by incubating them in RPMI1640 medium; 0.05% colla-Abbreviations: iNOS, inducible nitric oxide synthase; mRNA, messenger RNA.