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Dexamethasone Administration (dexamethasone + administration)
Selected AbstractsEffects of Dexamethasone on the Expression of Transforming Growth Factor-, in the Mouse Model of Allergic RhinitisTHE LARYNGOSCOPE, Issue 8 2007Seung-Sin Lee MD Abstract Objectives/Hypothesis: This study aimed to evaluate the effect of dexamethasone on the expression of transforming growth factor (TGF)-, in the mouse model of allergic rhinitis. Study Design: Female BALB/c mice were randomly assigned to four groups, including two control groups and two treatment groups. Methods: General sensitization and local challenge were performed with ovalbumin (OVA). In the treatment groups, dexamethasone was injected intraperitoneally 3 hours before general sensitization or local challenge. Symptom score, eosinophil infiltration, and immunostaining for TGF-,1 and CD4 in nasal mucosa, and TGF-,1 and OVA-specific immunoglobulin E (IgE) in sera were analyzed. Results: Dexamethasone administration before general sensitization reduced the symptom score, OVA-specific IgE, and eosinophil infiltration and increased the serum level of TGF-,1 significantly. Dexamethasone administration before local challenge reduced only the eosinophil infiltration significantly. Immunoreactivity of TGF-,1 and CD4 was lower in both treatment groups. Conclusion: These results suggest that dexamethasone may play an important role in the regulation of allergic reactions by at least two mechanisms; one by suppressing allergic sensitization through decrease of CD4+ T cells and increase of TGF-,, and the other by suppressing late allergic reactions through the inhibition of proliferation and chemotaxis of inflammatory cells such as eosinophils. [source] Dexamethasone administration inhibits skeletal muscle expression of the androgen receptor and IGF-1 , implications for steroid-induced myopathyCLINICAL ENDOCRINOLOGY, Issue 1 2010Warrick J. Inder Summary Context, Glucocorticoids are a well-recognized cause of muscle weakness. The early effects of glucocorticoids on skeletal muscle (SkM) androgen and IGF-1 pathways have not been previously investigated in human subjects. Objective, To determine if administration of the potent glucocorticoid dexamethasone down-regulates SkM androgen receptor and the IGF-1 signalling pathway. Methods and subjects, Twenty-four subjects (12 men and 12 women), including 12 with type 2 diabetes and 12 nondiabetics were enrolled. Venous blood sampling and biopsy of vastus lateralis were performed before and after administration of oral dexamethasone 4 mg/day for 4 days. Main outcome measures, Changes in plasma testosterone and IGF-1, SkM androgen receptor mRNA, SkM IGF-1mRNA and SkM IGF-1 receptor mRNA by quantitative RT-PCR after dexamethasone. Results, Relative expression of SkM androgen receptor was similar in male (1·63 ± 0·37) vs. female (1·57 ± 0·30) subjects, despite the significant difference in plasma testosterone levels. Plasma IGF-1 and SkM expression of IGF-1 and IGF-1 receptor were also similar between males and females. Following dexamethasone, there was a significant down-regulation of SkM androgen receptor (1·60 ± 0·23 vs. 1·11 ± 0·16, P < 0·05) and IGF-1 (1·72 ± 0·29 vs. 1·06 ± 0·14, P < 0·05) mRNA, but no change in expression of the IGF-1 receptor. Plasma testosterone fell significantly in both sexes (male: 15·0 ± 1·3 vs. 11·3 ± 1·2 nmol/l, P < 0·01, female: 1·8 ± 0·5 vs. 0·5 ± 0·1 nmol/l, P < 0·05). Conclusions, Exogenous steroid excess results in relative androgen deficiency at two levels, reduced circulating testosterone and SkM androgen receptor mRNA, along with reduced SkM IGF-1 mRNA. These defects may contribute to the development of steroid-induced myopathy. [source] Theophylline does not potentiate the effects of a low dose of dexamethasone in horses with recurrent airway obstructionEQUINE VETERINARY JOURNAL, Issue 6 2006C. CESARINI Summary Reasons for performing study: Theophylline has been shown to have corticosteroid-sparing effects for the treatment of human asthma. A similar effect, if present in horses, would allow diminishing the dose of corticosteroids administered to equine patients with inflammatory airway diseases. Objectives: To evaluate whether theophylline potentiates the effects of a low dose of dexamethasone when treating horses with recurrent airway obstruction (RAO). Hypothesis: Theophylline has steroid-sparing effects in horses with RAO. Methods: Ten mature mixed breed horses in clinical exacerbation of RAO were studied. Using an incomplete crossover design and 3 experimental periods of 7 days duration, horses were distributed randomly in 5 treatment groups; and administered dexamethasone s.i.d., at either 0.05 mg/kg bwt i.v. or per os, or 0.02 mg/kg bwt alone or combined with theophylline at 5 mg/kg bwt per os b.i.d. A fifth group was treated with theophylline alone at the above dosage. Lung function was evaluated prior to drug administration and then 3 and 7 days later. Results: Oral administration of dexamethasone alone or combined with theophylline failed to improve lung function significantly in RAO affected horses. Theophylline alone also failed to improve lung function in all treated horses. Conversely, dexamethasone administration at 0.05 mg/kg bwt i.v. resulted in a significant improvement in lung function starting on Day 3. Conclusions and potential relevance: Oral theophylline for 7 days did not improve the effects of a low dose of dexamethasone for the treatment of horses with RAO. [source] Effects of maternal dexamethasone administration on fetal Doppler flow velocity waveformsBJOG : AN INTERNATIONAL JOURNAL OF OBSTETRICS & GYNAECOLOGY, Issue 4 2000Yvon Chitrit Consultant Objective To investigate the effects of maternal dexamethasone administration on umbilical and fetal cerebral artery flow velocity waveforms. Design Cross-sectional study. Setting Department of Obstetrics and Gynaecology, Robert Ballanger Hospital, Aulnay-sous-Bois, France. Sample Twenty-six pregnant women with singleton pregnancies considered at risk for preterm delivery. At baseline, all pregnancies had normal fetoplacental vascular resistance. Methods These women were given weekly six intravenous doses of 4 mg of dexamethasone eight hours apart. Main outcome measures Doppler studies were performed from both umbilical artery (UA) and fetal middle cerebral artery (MCA) before (day 0), during (day 2), immediately after (day 4) and shortly after (day 7) every steroid course. Results No significant variation was noted in both umbilical artery pulsatility index (PI) and fetal heart rate through dexamethasone therapy. Compared with mean initial values, we found on day 4 a significant decrease in MCA PI of 0.28 (F = 7.17, P < 0.001) and a significant increase in UA:MCA PI ratio of 0.08 (F = 3.85, P= 0.013); in contrast no significant change was documented on days 2 and 7 in both MCA pulsatility index and UA:MCA PI ratio. After multiple regression analysis, only the decrease in fetal middle cerebral artery pulsatility index on day 4 remained significant (F=5.84, P= 0.001). Conclusions The current study finds in healthy fetuses a transient, significant and unexplained decrease in fetal middle cerebral artery impedance on the fourth day following maternal dexamethasone administration. Further basic research and clinical studies including larger sample sizes or pregnancies with fetoplacental dysfunction are needed. [source] Early dexamethasone decreases expression of activation markers on neutrophils and monocytes in preterm infantsACTA PAEDIATRICA, Issue 11 2002I Nupponen Aim: To investigate the effects of early dexamethasone administration on activation of circulating neutrophils and monocytes in preterm infants with respiratory distress syndrome requiring treatment with surfactant. Methods: Neonates (n= 30) with respiratory distress were randomized to receive dexamethasone (DEX group, 29.1 ± 1.2 wk, 1223 ± 156 g, n= 15) from the first postnatal day, or to serve as controls (control group, 29.2 ± 1.4 wk, 1250 ± 148 g, n= 15). Dexamethasone was given as a 4 d course (0.5 mg kg,1 on postnatal days 1 and 2, and 0.25 mg kg,1 on days 3 and 4). Polymorphonuclear leucocyte (PMN) and monocyte surface expression of CD11b, L-selectin and CD14 was quantified with flow cytometry, and plasma macrophage-inflammatory protein-1, (MIP-1,) with an enzyme-linked immunosorbent assay. Blood samples were collected on days 1, 2,3 and 5,7. Results: In the DEX group 1/15, and in the control group 7/15 developed bronchopulmonary dysplasia (p < 0.04). PMN CD11b (median 100, range 70-190 vs 154, 96,213, p= 0.01), monocyte CD14 (235, 102,433 vs 355, 219,533, p= 0.01) and plasma MIP-1, (20 ng 1,1, 20,32 vs 37 ng 1,1, 20,70, p= 0.005) were lower in the DEX group at days 2,3. All adhesion molecule expression and plasma MIP-1, levels were comparable at days 5,7, with the exception of monocyte L-selectin expression levels, which remained lower in the DEX group. Conclusion: In preterm infants with respiratory distress syndrome, early dexamethasone causes downregulation of PMN and monocyte activation. This may attenuate pulmonary inflammation and improve pulmonary outcome. [source] | ||||||||||