Renal prostaglandin E2 synthesis and degradation in the developing rat

Postnatal development of glomerular filtration rate (GFR) and renal blood flow is associated with a fall in renal vascular resistance that may be mediated by vasoactive substances. We examined differences in the regulation of one such substance, prostaglandin E2 (PGE2). The present studies examined renal cortical and medullary PGE2 synthesis and degradation in rats aged 20 days (30.7 g), 31 days (101 g), and 120 days (413 g). PGE2 synthesis in cortical microsomes was highest in 20-day-old rats compared to 31- and 120-day-old rats. In contrast, medullary PGE2 synthesis was lowest in 20-day-old rats compared to 31- and 120-day-old rats. Both cortical and medullary PGE2 degradation were highest in 20-day-old rats and decreased with age. Despite demonstrating significant age-dependent differences in cortical and medullary PGE2 synthesis, 11 days of aspirin given between age 20-31 days blocked PGE2 synthesis in cortex and medulla by 60 and 76%, respectively, but GFR was similar to control 31-day-old rats (0.78 +/- 0.04 ml/min/g kidney weight, aspirin-treated, versus 0.85 +/- 0.03 ml/min/g kidney weight, control), suggesting that observed age-dependent differences in renal PGE2 synthesis is not a major determinant of development of GFR. A more important determinant of GFR may be age- related differences in renal cortical prostaglandin turnover.     

Oxygen-related prostaglandin synthesis in ductus arteriosus and other vascular cells

We compared oxygen-related prostaglandin synthesis in fetal lamb ductus arteriosus (DA) pulmonary artery (PA) and aorta endothelial and smooth muscle cells. We measured basal synthesis of 6-keto-PGF1 alpha and PGE2, the response to calcium ionophore (A23187), a nonspecific stimulus of prostaglandin production, as well as the response to oxygen, a perinatal stimulus, monitoring both the effects of hyperoxia (95% O2) and hypoxia (2% O2). In addition, we established whether differences observed in fetal lamb PA cells related to oxygen tension were also observed in newborn central and microvessel PA cells. Our results indicate that DA endothelial cells increase 6-keto-PGF1 alpha in response to ionophore (p less than 0.05). With hyperoxia, DA endothelial cells increase PGE2 synthesis and DA smooth muscle cells increase 6-keto-PGF1 alpha (p less than 0.05 and 0.02, respectively). Aorta smooth muscle cells increase 6-keto-PGF1 alpha in response to ionophore and hyperoxia (p less than 0.003 and 0.05, respectively). PA endothelial and smooth muscle cells have higher levels of basal prostaglandin synthesis when compared with DA and aorta. In response to ionophore, increased 6-keto-PGF1 alpha is observed in both PA endothelial and smooth muscle cells (p less than 0.02 and 0.0004, respectively), and PGE2 is increased in PA smooth muscle cells (p less than 0.003). Hypoxia, however, decreases PA smooth muscle production of both 6-keto-PGF1 alpha and PGE2 (p less than 0.02 and 0.01, respectively). Similar observations were made in newborn lamb central and microvessel PA cells.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of rat atrial natriuretic factor on in vivo and in vitro aldosterone and corticosterone secretions in the rat during the perinatal period.

The effect of rat atrial natriuretic factor (rANF) on aldosterone and corticosterone secretion was investigated in vivo in 21-day-old rat fetuses injected intravenously through the umbilical vein and in vitro on isolated adrenal cells from 17-, 19- and 21-day-old fetuses and 1-, 2-, 3- and 4-week-old rats. In vivo, rANF (50 pmol/50 microliters/fetus) inhibited both basal levels and secretion of aldosterone stimulated by adrenocorticotropin hormone (ACTH(1-24), 0.25 pmol/50 microliters/fetus), but not corticosterone secretion. In vitro, the addition of graded concentrations of rANF (0.001, 0.01 and 10 nmol/l) to the incubation medium did not affect the basal aldosterone and corticosterone secretions of fetal and neonatal adrenal cells. ACTH(1-24) (0.1 nmol/l) stimulated productions of both corticosterone and aldosterone by the adrenal cells at all stages studied. The addition of graded concentrations of rANF to the incubation medium containing ACTH(1-24) (0.1 nmol/l) induced a dose-dependent inhibition of aldosterone secretion by the adrenal cells from 21-day-old fetuses and newborn rats. In contrast, no effect was observed on cells from 17- and 19-day-old fetuses. At all stages investigated, the three doses of rANF were unable to affect ACTH-induced corticosterone secretion in vitro. In isolated adrenal cells from 2-week-old rats, rANF (10 nmol/l) inhibited the secretion of aldosterone induced by ACTH(1-24) (0.1 nmol/l), and by different steroids of the aldosterone synthetic pathway (progesterone, 11-deoxycorticosterone, corticosterone, 1 mumol/l for each steroid). These results suggest that rANF is a specific inhibitor of aldosterone synthesis in the perinatal period of the rat and that the inhibitory effect of rANF occurs both during the early and late pathways of aldosteroidogenesis.     

Adrenal response in children receiving high doses of ketoconazole for systemic coccidioidomycosis

The effect of ketoconazole on adrenal cortical function was studied in 10 prepubertal children receiving long-term (3 to 52 months) high-dose (10 to 23 mg/kg/d) orally administered ketoconazole treatment because of systemic coccidioidomycosis. Four hours after the once daily morning dose of ketoconazole, the patients had significantly elevated baseline desoxycorticosterone (DOC) and precursor/product ratios, and blunted cortisol and aldosterone responses to ACTH stimulation. Twenty-four hours after ketoconazole ingestion, both DOC and DOC/corticosterone ratio were approaching normal; the cortisol response to ACTH was normal in all but two of the 10 study patients, and these two had significantly improved response compared with their own 4-hour values. There appeared to be no differential adrenal response related to either duration of treatment (greater than 12 vs less than 12 months) or dose of medication per kilogram (greater than 18 or less than 18 mg/kg/d). Our data suggest that ketoconazole impairs production of cortisol and aldosterone by imposing a partial and temporary block at the 11-beta-hydroxylase step of steroid hormone synthesis. None of the patients required adrenal steroid replacement therapy in times of acute illness or surgery, and none had clinical evidence of adrenal insufficiency.     

Long-term outcome of the fetal adrenal gland transplantation in rats.

Three experimental groups have been constructed to evaluate the long-term outcome of fetal adrenal transplantation in rats. In Group 1 (n = 10), rats underwent bilateral adrenalectomy. In Group 2 (n = 10), rats underwent a sham procedure which included flank incision and arterial canulization. In Group 3 (n = 20), a left adrenalectomy was performed followed immediately by transplantation of a fetal adrenal graft into the greater omentum and marked with a prolene suture (Stage 1). One year later, the right adrenal gland of the recipient was removed followed by a determination of the fetal adrenal graft function (Stage 2). Graft function was evaluated by measuring ACTH and corticosterone levels; and a histologic examination of the transplanted fetal adrenal gland was obtained at autopsy. In Group 1, all the rats died within first 8 hours, following bilateral adrenalectomy. In Group 2, and Group 3, all rats survived after Stage 1 operation. During the Stage 2 operation, it was observed that three rats (15%) had neither fetal adrenal transplant nor prolene suture, seven rats (35%) had a well vascularized and developed fetal adrenal graft and a prolene suture. There was no visible fetal adrenal graft but the prolene suture was present in the remaining rats (50%) in Group 3. After removal of the right adrenal gland (6 and 12 hours later), the mean plasma level of ACTH increased with a decline in mean serum corticosterone level in Group 3 compared to the sham-operated animals (p < 0.001). In spite of visible, and viable transplants, all rats died within 48 hours following Stage 2 operation. The mean weight of the fetal adrenal transplant showed a sixteen-fold increase compared to the initial weight (p < 0.001) and histologic examination showed all 3 zones of adrenal cortex, but there were no medullary cells noted. Although the transplanted fetal adrenal grafts survived, their hormonal function was not enough to maintain host viability. Based on these results it is concluded that, insufficiency of the transplanted fetal adrenal gland may be secondary to either graft rejection or suppression of the transplanted tissue by the functional recipient adrenal despite the fetal adrenal transplant survival.     

Acidemia potentiates the plasma catecholamine response to hypoxemia in fetal sheep

Though hypoxemia has been shown to stimulate adrenal medullary catecholamine (CA) release and raise plasma CA concentrations, the extent to which concomitant acidosis influences the magnitude of this response is unclear. Eleven chronically catheterized late gestation (0.8 term) fetal lambs in utero were investigated during a baseline control period and following the onset of umbilical cord constriction-induced hypoxemia (PO2 = 5-15 Torr). Plasma CA rose in response to hypoxemia in all animals but was potentiated by the development of acidemia. Baseline norepinephrine (NE = 487 +/- 113 pg/cm3 and increased to 1,386 +/- 127 pg/cm3 (p less than 0.001) in response to hypoxemia. Hypoxemia combined with acidemia promoted an even greater rise in NE to 6,726 +/- 1,289 pg/cm3 (p less than 0.05). Plasma epinephrine (E) = 99 +/- 36 pg/cm3 during baseline observations and increased to 512 +/- 81 pg/cm3 (p less than 0.001) in response to hypoxemia. However, an additional 9-fold increase (p less than 0.05) was noted when hypoxemia was combined with acidemia (E = 4,311 +/- 1,449 pg/cm3). Thus, acidosis significantly potentiates the magnitude of the plasma CA response to hypoxemia in the late gestation fetus.     

Prostaglandin E2 attenuates hyperoxia-induced injury in cultured rabbit tracheal epithelial cells.

We assessed the kinetics of hyperoxia-induced prostaglandin E2 (PGE2) production by cultured rabbit tracheal epithelial (TE) cells with different inherent capacities to generate PGE2 and the role of endogenous PGE2 production in protecting these cells from hyperoxic injury. Rabbit TE cells grown to confluence with or without lipid supplements [0.1% Excyte III (Miles-Pentex) and 1 microM arachidonic acid] were exposed for 2 h to control (5% CO2/air) or hyperoxic (5% CO2/90% O2) atmospheres at a gas-fluid interface. Serial cell culture effluents collected during exposure were analyzed for PGE2 by enzyme-linked immunoassay. Basal PGE2 production by lipid-supplemented cells was approximately 3-fold greater than that by unsupplemented cultures (p less than 0.01). In lipid-supplemented cells, PGE2 production doubled after 15 min of hyperoxic exposure (p less than 0.05) and then declined to approximately 50% of initial levels, whereas exposure to 5% CO2/air did not significantly change PGE2 production. In unsupplemented cells, neither control nor hyperoxic exposure altered PGE2 production. Hyperoxia-exposed TE cells had decreased ability to convert 10 microM exogenous arachidonic acid to PGE2, suggesting hyperoxia-induced inhibition of the enzymes involved in PGE2 synthesis. Lipid-supplemented cells were less susceptible to hyperoxic injury than unsupplemented monolayers, as evidenced by increased viability (trypan blue exclusion) and decreased generation of lipid peroxides (thiobarbituric acid reactive substances). Addition of exogenous PGE2 to unsupplemented cultures at concentrations that were produced by lipid-supplemented cells (2 ng/mL every 15 min) during hyperoxic exposure eliminated these differences in hyperoxia-induced lipid peroxidation and cytotoxicity.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of prostaglandin E2 on adenylate cyclase activity in isolated glomeruli and tubules during postnatal maturation of rat renal cortex

To examine the effect of prostaglandins on adenylate cyclase during the postnatal maturation of kidney, the prostaglandin E2 (PGE2) responsiveness of adenylate cyclase in the absence and presence of exogenous GTP was investigated in glomeruli and tubules isolated from renal cortex of 14-, 21- and 30-day-old rats. In the absence of GTP, the adenylate cyclase response to PGE2 in glomeruli of 14-day-old rats was about fourfold higher than that in 21- and 30-day-old rats. In the tubules there was an about 30-35% decrease in the enzyme response to the prostaglandin between 14 and 21 days as well as between 21 and 30 days. When GTP was present, the PGE2 responsiveness of adenylate cyclase was of the same order of magnitude in glomeruli at 14 and 21 days and lower at 30 days. Under the same conditions, no significant changes were observed in the cortical tubules throughout the period studied. Thus association of PGE2 plus GTP suggests that during the postnatal maturation of rat kidney, the response of adenylate cyclase to PGE2 remains unchanged in cortical tubules and slightly decreases in glomeruli.     

The sensitivity of the fetal rat adrenal gland to adrenocorticotropic hormone in vivo and in vitro

Rat fetuses were treated with 1 IU ACTH on day 16 or 17 of gestation and autopsied on the next day. Other fetuses of the same litter were treated with saline alone. The adrenal glands of ACTH-treated fetuses were significantly heavier than those of saline-treated fetuses and of intact controls in every experimental period. These changes in the weight of fetal adrenal glands reflect histologically on changes in the size of adrenocortical cells which were enlarged in response to injected ACTH. Adrenal glands from rat fetuses of different ages were explanted to organ cultures for 2 days, in medium with or without ACTH added. The 13-day adrenal glands were not able to respond to ACTH, but the response appeared abruptly in the 14-day adrenal glands, judging from the increased cell size in histological sections. The overall results suggest that the fetal adrenal gland begins to respond to ACTH from day 14 of gestation.     

Modulation of glucocorticoid secretion by growth hormone

We measured the cortisol and corticosterone responses to insulin-induced hypoglycemia in 13 growth hormone (GH)-deficient children and 30 short children without GH deficiency. Although there was no difference between the two groups in degree of hypoglycemia attained, baseline cortisol, baseline corticosterone, or cortisol 40 min after insulin injection, GH-deficient children had a significantly greater corticosterone response to this stress (3.6 +/- 0.4 versus 1.9 +/- 0.2 micrograms/dl). (All data are presented as mean +/- SEM.) In order to explore the effect of GH on corticosterone secretion, we measured cortisol and corticosterone responses to synthetic (1-24) ACTH before and after 3 days of exogenous GH (0.2 unit/kg/day). In 13 GH-deficient children, GH treatment caused a significant decrease in the corticosterone response to ACTH (2.2 +/- 0.2 micrograms/dl before GH to 1.6 +/- 0.2 micrograms/dl; t = 5.22, p less than 0.001; paired t test) despite the fact that there was no significant change in the cortisol response to ACTH (18 +/- 2 micrograms/dl before and 16 +/- 2 micrograms/dl after). When seven short children who were not GH deficient underwent a similar 3-day course of GH, the decrease in their corticosterone response was much less although still statistically significant (2.0 +/- 0.5 to 1.8 +/- 0.5 micrograms/dl; paired t test, p less than 0.05). Again, the stimulated levels of cortisol were not affected by GH treatment (19 +/- 4 versus 18 +/- 3 micrograms/dl) These results indicate that GH modulates the adrenal response to ACTH by suppressing corticosterone secretion without affecting cortisol secretion. In summary, this study presents two new findings.(ABSTRACT TRUNCATED AT 250 WORDS)     

Role of hypothalamic-pituitary axis in EGF action on maturation of adrenal gland in fetal rhesus monkey in vivo

We determined the route of action of epidermal growth factor (EGF) [intraperitoneal (IP) versus intraamniotic administration] on adrenal development and whether its effects are mediated via the fetal hypothalamic-pituitary axis in the fetal rhesus monkey in vivo. EGF (40 microg) was administered IP (n = 9) or intraamniotic (n = 6) at 121, 123, 125, and 127 d gestation (term, approximately 165 +/- 10 d gestation). In addition, a competitive corticotropin-releasing factor antagonist ([D-phenylalanine(12), Norleucine(21,38)] corticotropin-releasing factor(12-41) to block fetal pituitary ACTH secretion; 400 microg IP) and metyrapone (11beta-hydroxylase inhibitor to block adrenal cortisol synthesis; 15 mg IP and 15 mg intraamniotic) were administered, in combination with EGF (EGF+BLOCK; 40 microg IP; n = 4 fetuses). Control fetuses (n = 6) received saline injections in an equivalent volume. On gestational d 128, a hysterotomy was performed, and fetal adrenals were collected for morphometric analyses and immunocytochemical localization of 3beta -hydroxysteroid dehydrogenase (3betaHSD) and cytochrome P-450 11beta -hydroxylase/aldosynthase. Definitive zone (DZ) width and cortical width of 3betaHSD staining were significantly greater (p < 0.05) in the EGF IP-treated fetuses compared with controls and EGF+BLOCK. With EGF IP, 3betaHSD was increased in the DZ and induced extensively in the transitional zone of the fetal adrenal cortex, and cytochrome P-450 11beta-hydroxylase/aldosynthase immunoreactivity was induced to detectable levels in the DZ. The administration of EGF+BLOCK inhibited the expression of 3betaHSD in the transitional zone, but 3betaHSD expression was still increased in the DZ and cytochrome P-450 11beta-hydroxylase/aldosynthase immunoreactivity was induced in the DZ. EGF intraamniotic administration had no significant effect on the width of the DZ or cortical width of 3betaHSD staining compared with controls. These data suggest that EGF acts via the hypothalamic-pituitary axis to modulate adrenal cortical growth and functional maturation of the transitional zone (the putative zona fasciculata), whereas EGF can act independently of the hypothalamic-pituitary axis to stimulate functional maturation of the DZ (the putative zona glomerulosa).     

生长激素缺乏症患儿重组人生长激素治疗前、后肾上腺皮质功能的变化

目的观察生长激素缺乏症(GHD)患儿重组人生长激素(rh GH)治疗前、后肾上腺皮质功能的变化。方法选取72例确诊GHD并接受rh GH治疗6个月以上的患儿,其中32例伴促肾上腺皮质激素(ACTH)缺乏,回顾性分析其在接受rh GH治疗前及治疗后3、6个月时清晨空腹血皮质醇(COR)、ACTH水平的变化。结果 32例伴ACTH缺乏患儿通过外源性补充氢化可的松(HC)使COR达正常水平后,再开始rh GH治疗,治疗前COR水平和使COR达正常下限时的HC剂量呈显著负相关(r=-0.899,P0.01)。单纯HC治疗1个月后COR水平较治疗前明显增高,ACTH水平明显下降,差异均有统计学意义(P0.001);经rh GH和HC替代治疗后3、6个月后COR及ACTH水平与单纯HC治疗1个月差异无统计学意义(P0.05)。40例无ACTH缺乏患儿在rh GH治疗后COR水平显著降低,与治疗前比较差异有统计学意义(P0.01),其中10例MRI显示下丘脑-垂体异常患儿表现为COR水平低下。结论 GHD患儿在rh GH治疗过程中可出现肾上腺皮质功能减低,特别是MRI显示垂体异常的患儿,应注意监测肾上腺皮质功能,及早干预。     

The relationship between ovarian structure and hyperandrogenism in premature pubarche

The aim of this study was to describe the ovarian structure (OS) and its relationship with hyperandrogenism in girls with premature pubarche (PP). A pelvic ultrasound was carried out in 23 girls with PP and in 57 prepubertal age-matched controls (C), and the OS was subdivided into five classes (c): 1-homogeneous; 2-microcystic, 3-multicystic, 4-polycystic and 5-follicular. In the girls with PP, an ACTH test was performed, and the presence of hormonal levels >3 SD of postpubertal normal levels and not compatible with late-onset congenital adrenal hyperplasia were considered an exaggerated response. The fasting levels of glucose (G) and insulin (I) were measured and the fasting I to G ratio (FIGR) was calculated. FIGR >22 was suggestive of I resistance (IR). The microcystic structure (c2) was more frequently found in the PP than in the C group (63% vs 35%, p=0.03). In the PP group, we observed the following OS: cl (n=6), c2 (n=15), c3 (n=1) and c4 (n=1). 11-Deoxycortisol--both basal and after ACTH--was greater in the PPc2 group than in PPc1 (p=0.04, p=0.0008, respectively). We also observed an exaggerated response to ACTH in 87% of the girls with PP, greater in the PPc2 group than in PPc1 (p=0.04). The FIGR showed IR in 44% of girls with PP, but I levels and FIGR were similar between PPc1 and PPc2. These findings suggest generalized adrenocortical hyperresponsiveness in girls with PP, which is more accentuated in PPc2. Long-term follow-up of girls with PP into adulthood is warranted to ascertain whether microcystic ovarian structure precedes functional ovarian hyperandrogenism.     

Plasma adrenocorticotropin, cortisol, and dehydroepiandrosterone response to corticotropin-releasing factor in normal children during pubertal development

The adrenocorticotropin (ACTH), cortisol, and dehydroepiandrosterone responses to synthetic human corticotropin-releasing factor (CRF) were studied in 28 endocrinologically healthy children (age 1-16 yr) and in six adult volunteers (age 24-42 yr). CRF was given as an intravenous bolus (1 microgram/kg body weight) between 0900 and 1000 hr. Significant increments in ACTH and cortisol levels after CRF were observed in all subjects, with an ACTH peak value of 48.2 +/- 3.4 pg/ml at 10 min (p less than 0.001). The ACTH and cortisol response patterns after CRF did not change with age or pubertal maturation and did not differ in children and in adults. In contrast, the dehydroepiandrosterone response to CRF clearly was related to the stage of pubertal development. The peak value after CRF significantly increased from puberty stage 1 to puberty stage 5 (164 +/- 18 versus 779 +/- 86 ng/100 ml, p less than 0.001). In adults, the mean dehydroepiandrosterone peak value after CRF did not differ from that of P5 children. These results show that CRF can be given safely to children. The absence of age-dependent ACTH and cortisol responses and a dehydroepiandrosterone response changing with pubertal maturation points to the existence of factors involved in the control of adrenal androgen production other than ACTH.     

促肾上腺皮质激素刺激对脓毒症及脓毒性休克患儿肾上腺功能评估的意义

目的 探讨小剂量(1μg/1.73 m2)促肾上腺皮质激素(ACTH)刺激实验评估儿童脓毒症和脓毒性休克肾上腺功能状态的价值.方法 患儿入院24h内完成基础皮质醇(T0)测定,静脉注射1μg/1.73m2 ACTH,30 min后测定血液皮质醇(T1),根据T0和皮质醇增值(△max=T1-T0)判断肾上腺功能,以△max≤90μg/L为肾上腺功能障碍(AI)指标.结果 62例中,脓毒症53例,脓毒性休克9例,病死率为27.4%(17/62).肾上腺功能障碍(adrenal insufficiency,AI)发生率40.3%(25/62),其中脓毒症和脓毒性休克患儿AI发生率分别是39.6%和44.4%,差异无显著统计学意义(P>0.05).两组脓毒症和脓毒性休克平均T0和T1分别是(318.6±230.4)μg/L、(452.3±230.7)μg/L和(454.7±212.7)μg/L、(579.3±231.9)μg/L,差异无统计学意义(P>0.05).存活组和死亡组患儿T0、T1分别是(320.5±223.9)μg/L、(462.3±212.0)μg/L和(384.3±258.3)μg/L、(500.7±470.6)μg/L,两组AI发生率分别是37.8%和47.1%,差异无统计学意义(P>0.05).T0和T1水平与儿童危重病例评分(PCIS)有关(P<0.05),AI发生率与PCIS、PRISMⅢ和器官功能障碍数目无关(P>0.05).结论 儿童脓毒症和脓毒性休克患儿AI发生率较高.小剂量ACTH刺激实验可以判断严重感染患者肾上腺功能,可为激素治疗提供依据.     

Adrenal axis function after high-dose steroid therapy for childhood acute lymphoblastic leukemia

Background A 4‐week course of high‐dose glucocorticoids may cause prolonged adrenal suppression even after a 9‐day tapering phase. In this study, adrenal function and signs and symptoms of adrenal insufficiency were prospectively assessed in children with acute lymphoblastic leukemia (ALL) after induction treatment including high‐dose prednisone (PDN) or dexamethasone (DXM). Procedures Sixty‐four children with ALL, treated according to the AIEOP ALL 2000 Study protocol, underwent low dose ACTH (LD‐ACTH) stimulation 24 hr after the last tapered steroid dose. In those with impaired cortisol response, additional LD ACTH tests were performed every 1–2 weeks until cortisol levels normalized. Signs and symptoms of adrenal insufficiency were recorded during the observation period. Results All patients had normal basal cortisol values at diagnosis. Twenty‐four hours after last glucocorticoid dose, morning cortisol was reduced in 40/64 (62.5%) patients. LD‐ACTH testing showed adrenal suppression in 52/64 (81.5%) patients. At the following ACTH test 7–14 days later, morning cortisol values were reduced in 8/52 (15.4%) patients and response to the test was impaired in 12/52 (23%). Adrenal function completely recovered in all patients within 10 weeks. No difference was found between patients treated with PDN or DXM. Almost 35% of children with impaired cortisol values at the first test developed signs or symptoms of adrenal insufficiency. One child developed a severe adrenal crisis during adrenal suppression. Conclusions High‐dose glucocorticoid therapy in ALL children may cause prolonged adrenal suppression and related clinical symptoms. Laboratory monitoring of cortisol levels and steroid coverage during stress episodes may be indicated. Pediatr Blood Cancer 2008;50:537–541. © 2007 Wiley‐Liss, Inc.     

Expression of Apoptosis-related Antigens, Fas, bcl-2, and p53, and Mib-1 Proliferation Index in the Hypoplastic Thymus of DiGeorge Syndrome

Apoptosis, along with cellular proliferation, plays a major role in normal developmental processes and tissue homeostasis. We hypothesized that altered apoptosis-related pathways and/or reduced cell proliferation might play a role in the thymic hypoplasia or aplasia in DiGeorge syndrome (DG). We used immunohistochemistry to evaluate the apoptosis-related antigens Fas (CD95), bcl-2, and p53, as well as Mib-1 proliferation index in the thymuses from six patients with DG. The results were compared with those from the thymuses from six patients with non-DG congenital heart disease. All DG patients (age 32 weeks GA to 4 months) had hypoplastic thymuses ranging from microscopic foci to 2.7 g in weight (expected for age, 4.7 ± 3.6 g to 10 ± 6 g). The thymic weights from the patients with non-DG congenital heart disease (age 37 weeks GA to 1 month) ranged from 3 to 5.6 g and were at the lower range of expected weight by age (expected for age, 8.4 ± 5.6 g to 12 ± 7 g). All thymuses showed histologic features of stress-induced involution. In both groups, a - 50% Mib-1 proliferation index was found in the cortical thymocytes, whereas <5% Mib-1 labeling was seen in the medullary thymocytes; Fas stained medullary epithelial cells (3+) and cortical epithelial cells (1+); bcl-2 stained medullary thymocytes (3+) and cortical thymocytes (1+); p53 stained less than 1% of nuclei in all sections. No significantly altered Mib-1 proliferation index or expression of Fas, bcl-2, and p53 was observed in the hypoplastic thymuses in DG, compared to these same measures in non-DG. These results suggest that thymic hypoplasia in DG may be mediated by mechanisms other than reduced cellular proliferation and/or altered Fas, bcl-2, and p53 apoptotic pathways.     

Human milk--derived oligosaccharides and plant-derived oligosaccharides stimulate cytokine production of cord blood T-cells in vitro

Human milk contains large amounts of free oligosaccharides (HMOs). HMOs have been shown to exert antiinflammatory properties, and evidence for their immunomodulatory effects is increasing. The purpose of this study was to evaluate influences of two human breast milk-derived oligosaccharide samples (neutral and acidic oligosaccharides), and of a low-molecular-weight fucoidan on cytokine production and activation of cord blood mononuclear cells. Cord blood mononuclear cells from randomly chosen healthy newborns were co-cultured with the oligosaccharide samples. By means of flow cytometry, intracellular cytokine production (d 20) and surface marker expression of T cells (d 5) were measured. In vitro-induced Ig levels were quantified nephelometrically (total IgG1) and by ELISA (total IgE) in the supernatant of cell cultures. The acidic oligosaccharide fraction increased the percentage of interferon-gamma producing CD3+CD4+ and CD3+CD8+ cells (p < 0.05) and the IL-13 production in CD3+CD8+ cells (p < 0.05). In acidic oligosaccharide cultures, CD25+ expression on CD3+CD4+ cells was significantly elevated (p < 0.05). Low-molecular-weight fucoidan induced IL-4 production in CD3+CD4+ T cells (p < 0.05) and IL-13 production in CD3+CD8+ T cells (p < 0.05), whereas interferon-gamma production remained unaffected in both T-cell populations. Ig production (total IgE and total IgG1) remained unaffected. Human milk-derived oligosaccharides and plant-derived oligosaccharides affect the cytokine production and activation of cord blood derived T cells in vitro. Therefore, oligosaccharides and, in particular, acidic oligosaccharides may influence lymphocyte maturation in breast-fed newborns.     

Inotropic effects of prostaglandin D2 and E1 on the newborn rabbit heart

This study determines the inotropic effects of prostaglandin D2 (PGD2) and prostaglandin E1 (PGE1) in the isolated, arterial perfused newborn (NB) and adult (A) rabbit heart. Significant positive inotropism of PGD2 was observed at all concentrations studied (1 X 10(-17) to 1 X 10(-7) M) in the two age groups; the effect in the NB was significantly greater (p less than 0.05) than that in the A at PGD2 concentrations higher than 1 X 10(-17) M. Significant positive inotropism of PGE1 was observed at PGE1 concentrations higher than 1 X 10(-8) M in the NB, and only at 1 X 10(-6) M in the A. In the NB, the relaxation parameters [1/2 RT and the ratio of +dT/dt (max) to -dT/dt (max)] decreased to 80% of control after PGE1 infusion, but not after PGD2 infusion. In contrast, relaxation parameters in the A were not different from control. Propranolol (1 X 10(-6) M) did not alter the positive inotropic action of PGD2 and PGE1 in the NB. These data indicate that: 1) the positive inotropic effects of PGD2 and PGE1 in NB are greater than that in the A, 2) PGE1 and not PGD2, enhances myocardial relaxation only in the NB, 3) the contractile effects of PGD2 and PGE1 are not mediated by beta-receptors.     

Adrenalectomy and pentagastrin effects on gastrointestinal cholinergic enzyme activities

The present study examined the effects of pentagastrin and adrenalectomy on choline acetyltransferase (ChAT) and acetylcholine esterase (AChE), enzymes which synthesize and degrade acetylcholine in the rat gastrointestinal tract. Adrenalectomized and non-adrenalectomized rats, 14 and 21 days old, were treated with either pentagastrin (250 micrograms/kg i.p.) or saline for 7 days. Rats were sacrificed at 21 and 28 days of age. Adrenalectomy- and pentagastrin-treated 21-day-old rats had greater ChAT activities than those treated with pentagastrin alone, while AChE activities were higher in the pentagastrin-treated group. Adrenalectomy- and pentagastrin-treated 28-day-old rats had lower levels of activity as compared to pentagastrin-treated rats. The adrenal gland does appear to influence the response of cholinergic enzyme activities to pentagastrin.