tRNA structural and functional changes induced by oxidative stress

Oxidatively damaged biomolecules impair cellular functions and contribute to the pathology of a variety of diseases. RNA is also attacked by reactive oxygen species, and oxidized RNA is increasingly recognized as an important contributor to neurodegenerative complications in humans. Recently, evidence has accumulated supporting the notion that tRNA is involved in cellular responses to various stress conditions. This review focuses on the intriguing consequences of oxidative modification of tRNA at the structural and functional level

Congenital Diaphragmatic hernia – a review

Congenital Diaphragmatic hernia (CDH) is a condition characterized by a defect in the diaphragm leading to protrusion of abdominal contents into the thoracic cavity interfering with normal development of the lungs. The defect may range from a small aperture in the posterior muscle rim to complete absence of diaphragm. The pathophysiology of CDH is a combination of lung hypoplasia and immaturity associated with persistent pulmonary hypertension of newborn (PPHN) and cardiac dysfunction. Prenatal assessment of lung to head ratio (LHR) and position of the liver by ultrasound are used to diagnose and predict outcomes. Delivery of infants with CDH is recommended close to term gestation. Immediate management at birth includes bowel decompression, avoidance of mask ventilation and endotracheal tube placement if required. The main focus of management includes gentle ventilation, hemodynamic monitoring and treatment of pulmonary hypertension followed by surgery. Although inhaled nitric oxide is not approved by FDA for the treatment of PPHN induced by CDH, it is commonly used. Extracorporeal membrane oxygenation (ECMO) is typically considered after failure of conventional medical management for infants ≥ 34 weeks’ gestation or with weight >2 kg with CDH and no associated major lethal anomalies. Multiple factors such as prematurity, associated abnormalities, severity of PPHN, type of repair and need for ECMO can affect the survival of an infant with CDH. With advances in the management of CDH, the overall survival has improved and has been reported to be 70-90% in non-ECMO infants and up to 50% in infants who undergo ECMO

Persistence of Pulmonary Hypertension by Echocardiography Predicts Short-Term Outcomes in Congenital Diaphragmatic Hernia

OBJECTIVES: To describe the natural history of pulmonary hypertension (PH) and the risk of death and pulmonary morbidity associated with the persistence of PH through the neonatal hospitalization for these infants. STUDY DESIGN: We performed a retrospective cohort study of infants with CDH cared for at UCSF (2002-12). Infants with other major anomalies or syndromes were excluded (n=43). Clinical echocardiograms were performed weekly for up to 6 weeks or until PH resolved off respiratory support or until hospital discharge. Echocardiograms were re-read by a blinded reviewer and categorized by severity of elevation in estimated pulmonary arterial pressure. PH was defined as ≥2/3 systemic blood pressure. Severity was determined by a hierarchy of ductus arteriosus level shunt, interventricular septal position, and tricuspid regurgitant jet velocity. RESULTS: Of 140 infants with ≥1 echo, 98 resolved their PH prior to death/discharge. Mean time to resolution was 18d (median 14d, IQR 8, 21d). Those with persistence of PH had a higher rate of ECMO (p<0.001) and death (p<0.001), and fewer ventilator-free days (p<0.001). Persistence of PH at 14d predicted mortality (AUC 0.87) and adverse respiratory outcomes (AUC 0.80-0.83). CONCLUSIONS: The majority of infants with congenital diaphragmatic hernia (CDH) resolve PH between 1 and 3 weeks of life. At 2 weeks of age, severity of PH by echocardiogram strongly predicts short-term pulmonary morbidity and death. Further evaluation of physiological alterations during that time may lead to novel therapies for severe CDH

Lentiviral-mediated over-expression of hyaluronan synthase-1 (HAS-1) decreases the cellular inflammatory response and results in regenerative wound repair

<p>Fetal wounds have been found to have increased levels of high-molecular-weight hyaluronan (HMW-HA) compared with those of adults. The primary enzyme responsible for producing HMW-HA is hyaluronic acid synthase-1 (HAS-1). We hypothesized that over-expression of HAS-1 in adult dermal wounds would decrease inflammation and promote regenerative healing. To test this hypothesis, the flanks of adult C57Bl/6 mice were treated with a lentiviral construct containing either HAS-1-GFP or GFP transgenes. After 48 h, a 4-mm excisional wound was made at the site of treatment. Wounds were harvested at days 3, 7, or 28 after wounding. Wound phenotype was assessed by histology to examine tissue architecture and immunohistochemistry for CD45. At 7 and 28 days, lenti-HAS-1-treated wounds demonstrated the restoration of the normal dermal elements and organized collagen fiber orientation. In contrast, the lenti-GFP-treated wounds lacked normal dermal architecture and demonstrated a disorganized collagen scar. At 3 and 7 days, wounds treated with lenti-HAS-1 exhibited a significant decrease in the number of inflammatory cells when compared with wounds treated with lenti-GFP. Thus, HAS-1 over-expression promotes dermal regeneration, in part by decreasing the inflammatory response and by recapitulation of fetal extracellular matrix HMW-HA content.</p>