Differential expression and regulation of the cAMP-selective phosphodiesterase type 4A splice variants in rat brain by chronic antidepressant administration

Chronic antidepressant treatment up-regulates the cAMP cascade in limbic brain regions, suggesting that activation of this pathway contributes to the therapeutic efficacy of antidepressants. A role for cAMP signaling is supported by the finding that rolipram, a selective inhibitor of cAMP-specific phosphodiesterases type 4 (PDE4), has antidepressant efficacy in behavioral models of depression and in clinical trials. To elucidate further the role of PDE4 isozymes, we characterized the expression and regulation of PDE4A splice variants (i.e. PDE4A1, PDE4A5, PDE4A8 and PDE4A10) in rat brain by chronic antidepressant treatment. Initial in situ hybridization studies (ISH) revealed high levels of PDE4A1 mRNA in medial septum, diagonal band, olfactory system, hippocampus and cerebellum. PDE4A5 mRNA expression was restricted to the olfactory nuclei, deep cortical layers, dentate and CA1 pyramidal layers. PDE4A10 mRNA was localized in the dentate gyrus and CA1 pyramidal layers. PDE4A8 mRNA was absent in rat brain. We determined the influence of chronic fluoxetine or electroconvulsive seizure (ECS) treatments on PDE4A splice variants expression in various brain regions. ISH analysis indicated that chronic fluoxetine or ECS treatments significantly increased PDE4A1, but not PDE4A5 or PDE4A10, mRNA levels in frontal and parietal cortices. ECS increased PDE4A5 levels in the anterior cingulate and frontoparietal cortices, CA1 and dentate gyrus, whereas chronic fluoxetine or ECS treatment increased PDE4A10 levels in the hippocampus. The differential up-regulation of PDE4A splice variants suggests compensatory region-specific responses to the antidepressant-induced increase in cAMP signaling and suggests that these splice variants may be relevant as targets for antidepressant intervention.     

Effects of erythropoietin on hyperoxic lung injury in neonatal rats

Pulmonary oxygen toxicity is believed to play a prominent role in the lung injury that leads to the development of bronchopulmonary dysplasia (BPD). To determine whether human recombinant erythropoietin (rhEPO) treatment reduces the risk of developing BPD, we investigated the effect of rhEPO treatment on the histopathologic changes seen in hyperoxia-induced lung injury of BPD. Twenty-five rat pups were divided into four groups: air-exposed control group (n = 5), hyperoxia-exposed placebo group (n = 7), hyperoxia-exposed rhEPO-treated group (n = 6), and air-exposed rhEPO-treated group (n = 7). Measurement of alveolar surface area, quantification of secondary crest formation, microvessel count, evaluation of alveolar septal fibrosis, and smooth muscle actin immunostaining were performed to assess hyperoxia-induced changes in lung morphology. Treatment of hyperoxia-exposed animals with rhEPO resulted in a significant increase in the mean alveolar area, number of secondary crests formed, and the microvessel count in comparison with hyperoxia-exposed placebo-treated animals. There was significantly less fibrosis in rhEPO-treated animals. However, treatment of hyperoxia-exposed animals with rhEPO did not result in a significant change in smooth muscle content compared with hyperoxia-exposed placebo treated animals. Our results suggest treatment with rhEPO during hyperoxia exposure is associated with improved alveolar structure, enhanced vascularity, and decreased fibrosis. Therefore, we conclude that treatment of preterm infants with EPO might reduce the risk of developing BPD.     

Disseminated intravascular coagulation in pediatric patients: clinical and laboratory features and prognostic factors influencing the survival

Although disseminated intravascular coagulation (DIC) has been a well-known disorder for many years, there is lack of sufficient number of clinical trials about incidence, frequency of underlying disorders, and prognosis of DIC in children. The aim of this study was to evaluate the frequency, etiologic factors, and clinical and laboratory findings of DIC and to determine the prognostic factors influencing the mortality in hospitalized pediatric patients. Medical records of 5535 children who were hospitalized were investigated. Sixty-two patients who were diagnosed as acute DIC were enrolled. The frequency of DIC was 1.12%. The underlying etiologic factors were infection in 59 patients (95.2%) and major trauma in 3 patients (4.8%). The frequency of bleeding and thrombosis was 48.8 and 4.8%. Respiratory, cardiovascular, hepatic, renal, neurologic, and gastrointestinal dysfunction was present in 71, 67.7, 35.5, 16.1, 16.1 and 11.3% of patients, respectively. Respiratory and cardiovascular dysfunctions were significantly associated with mortality. Multiorgan dysfunction syndrome (MODS) was present in 85.5% of the patients, and 54.8% of the patients had developed acute respiratory distress syndrome (ARDS). Mortality rate was significantly high in patients with MODS and ARDS. In multivariete logistic regression analysis, only ARDS and cardiovascular dysfunction had predictive and prognostic value on mortality. None of the diagnostic laboratory tests had predictive or prognostic value and the degree of abnormality of these tests did not show any correlation with mortality. In conclusion, DIC is not a rare disorder in hospitalized children, especially in patients with sepsis, and MODS, ARDS, and respiratory and cardiovascular system dysfunctions are poor prognostic factors.     

Interleukin-1alpha, interleukin-1beta, and interleukin-1Ra polymorphisms in febrile seizures

Febrile seizures are the most common form of childhood seizures. The exact mechanism promoting convulsions during a common febrile illness remains unknown, but it is accepted that genetic influences are likely to account for at least some of the cases. Previous studies reported high interleukin-1beta levels in the cerebrospinal fluid of patients with febrile seizures. Recently, an association between a regulatory polymorphism in the genes encoding interleukin-1beta and interleukin-1Ra and febrile seizures was reported. In this study, we attempted to confirm these findings. We analyzed the cytokine gene polymorphisms of interleukin-1beta, interleukin-1alpha, and interleukin-1Ra of 73 children with febrile seizure and 152 healthy controls. The distribution of interleukin-1beta -511, interleukin-1alpha -889, and interleukin-1Ra genotypes and alleles did not differ significantly between cases and controls. Our data suggest that the studied gene polymorphisms of interleukin-1beta, interleukin-1alpha, and interleukin-1Ra do not have a significant role in the pathogenesis of febrile seizures.     

Hypoglycemia after albuterol overdose in a pediatric patient

Albuterol overdose can lead to tachycardia, hypotension, tremor, hypokalemia, and hyperglycemia in children. Hypoglycemia had been previously reported in only one child. We describe a 3-year-old boy who ingested high-dose albuterol in this report. On arrival to the emergency department, the child was agitated and had noticeable restlessness, sinus tachycardia, mild hypokalemia (3.2 mEq/L), and hyperglycemia (187 mg/dL). Activated charcoal and intravenous hydration were given, and electrocardiogram monitoring was performed. Sinus tachycardia resolved within 4 to 6 hours. Hypoglycemia (45 mg/dL) was identified 4 hours after admission. The child recovered uneventfully within 24 hours with glucose replacement. This case suggests that hypoglycemia could be a late complication of acute albuterol overdose; thus, the period of observation should be extended in these cases.     

Effect of radioiodine therapy on thyroid nodule size and function in patients with toxic adenomas

BACKGROUND: Autonomously functioning toxic adenomas are a common cause of hyperthyroidism. Although 131I seems to be a good therapeutic option with little postablative hypothyroidism for these patients, only a small number of recent studies have objectively evaluated changes in nodule size by ultrasonography following radioiodine therapy. METHODS: We prospectively followed 39 patients with a mean age of 51.2 (35-75) years for 12 months and the patients who remained toxic thereafter, until euthyroidism was provided. Thyroid function tests, sonographic volumes were determined initially and 3, 6 and 12 months after treatment. Radioiodine doses of 3.7 MBq.g(-1) thyroid tissue corrected to a 100% 24 h 131I uptake were given. Thirty patients received a single dose, two required two doses and three required three to five doses of 131I due to persistent thyrotoxicosis. Sonographic volumes of the diffuse parts of the glands decreased significantly by 18% from a mean+/-SD value of 50+/-27.6 ml to 41+/-27.4 ml by the end of the 12 months. A significant decrease (8.3%, P=0.002) was achieved in the first three months. Toxic adenomas decreased in size more efficiently (54%) from a mean of 26+/-24 ml to 12+/-10 ml during 12 months, but also most significantly (28.8%, P=0.003) in the first 3 months of the follow-up. Thirty of the patients (76.9%) became euthyroid at the end of 12 months of follow-up. Four patients (10.3%) became overtly hypothyroid during the follow-up. CONCLUSION: Single or multiple doses of radioiodine can successfully treat toxic adenomas with a low rate of hypothyroidism and considerable nodule-volume reduction.