APOBEC signature mutation generates an oncogenic enhancer that drives LMO1 expression in T-ALL.

Oncogenic driver mutations are those that provide a proliferative or survival advantage to neoplastic cells, resulting in clonal selection. Although most cancer-causing mutations have been detected in the protein-coding regions of the cancer genome; driver mutations have recently also been discovered within noncoding genomic sequences. Thus, a current challenge is to gain precise understanding of how these unique genomic elements function in cancer pathogenesis, while clarifying mechanisms of gene regulation and identifying new targets for therapeutic intervention. Here we report a C-to-T single nucleotide transition that occurs as a somatic mutation in noncoding sequences 4 kb upstream of the transcriptional start site of the LMO1 oncogene in primary samples from patients with T-cell acute lymphoblastic leukaemia. This single nucleotide alteration conforms to an APOBEC-like cytidine deaminase mutational signature, and generates a new binding site for the MYB transcription factor, leading to the formation of an aberrant transcriptional enhancer complex that drives high levels of expression of the LMO1 oncogene. Since APOBEC-signature mutations are common in a broad spectrum of human cancers, we suggest that noncoding nucleotide transitions such as the one described here may activate potent oncogenic enhancers not only in T-lymphoid cells but in other cell lineages as well.

Compassion fatigue, burnout and compassion satisfaction in neonatologists in the US.

OBJECTIVE: Compassion fatigue (CF) is distress experienced by caregivers from ongoing contact with patients who are suffering. Burnout (BO) is occupational stress directly related to dissonance between job demands and available resources. Compassion satisfaction (CS) is professional fulfillment experienced through helping others. CF in physicians is not well studied. Neonatologists may be at particular risk for CF by virtue of recurrent exposure to distress in patients and their families. The objectives of this study were to determine the prevalence of CF, BO and CS, and to identify potential predictors for these phenomena in neonatologists. STUDY DESIGN: A modified Compassion Fatigue and Satisfaction Self-Test and a questionnaire of professional details and personal characteristics were distributed electronically to neonatologists nationally. Multivariable logistic and linear regression models for CF, BO and CS as a function of potential predictors were constructed. RESULTS: The survey response rate was 47%. The prevalence of CF, BO and CS was 15.7, 20.8 and 21.9%, respectively. Female gender, emotional depletion, distress from 'a clinical situation', 'co-workers', 'personal health issues' and 'not talking about distressing issues' were each significant determinants of CF. Emotional depletion, distress from the 'physical work environment' and 'co-workers', and 'not talking about distressing issues' were significant determinants of BO. Self-identification as Hispanic; 'not currently feeling distressed'; talking about distressing issues; and utilization of pediatric palliative care services were significant determinants of higher CS. CONCLUSIONS: CF and BO may impact emotional well-being and professional performance of neonatologists. Enhancement of CS is a potential target for intervention.

The spectrum of onset of acute kidney injury in premature infants less than 30 weeks gestation.

OBJECTIVE: To determine risk factors for acute kidney injury (AKI) in preterm infants as a function of time of onset. STUDY DESIGN: In this 5 1/2-year, single-center, retrospective study, incidence and timing of AKI was determined using modified Acute Kidney Injury Network criteria. Characteristics of newborns with and without AKI were compared by chi square and t-tests. Logistic regression was used to examine risk factors for AKI as a function of time of onset and potential confounders. RESULT: AKI occurred in 30.3% of 357 neonates; 72.2% was stage 1. Gestational ages (GA), initial Cr, maternal magnesium and volume resuscitation were associated with early AKI (days 0 to 1). Volume resuscitation, umbilical arterial line and receipt of non-steroidal anti-inflammatory drug (NSAID) for patent ductus arteriosus were associated with intermediate AKI (days 2 to 5). GA, steroids for early hypotension, necrotizing enterocolitis and sepsis were associated with late AKI (⩾day 6). CONCLUSION: Stage 1 AKI is a common morbidity in our population. Risk factors for AKI in our population differed with time of onset.

Relationship of maternal creatinine to first neonatal creatinine in infants <30 weeks gestation.

OBJECTIVE: To examine the relationship between maternal and neonatal creatinine (Cr) in preterm infants in the context of antenatal and intrapartum maternal and neonatal factors. STUDY DESIGN: In this 5½-year, single-center, retrospective study, paired maternal and neonatal Cr were compared by t-test. Linear regression for correlated outcomes employing generalized estimating equations was used to examine neonatal Cr as a function of antenatal maternal Cr and potential confounders. RESULT: A total of 157 neonates of 124 mothers met study criteria. Neonatal Cr values in the first 24 h of life were significantly higher than antenatal maternal values. Linear regression modeling showed that maternal Cr, neonatal lactate, hypoxic-ischemic villous changes on placental pathology and multiple gestation were each significant determinants of the first neonatal Cr. CONCLUSION: No neonatal Cr was less than its paired maternal value. Maternal Cr, neonatal lactate, hypoxic-ischemic villous changes in the placenta and multiple gestation were each significantly associated with neonatal Cr.

Impact of renal function and protein intake on blood urea nitrogen in preterm infants in the first 3 weeks of life.

OBJECTIVE: To examine the relationship between blood urea nitrogen (BUN) during the first 3 weeks of life and protein intake and creatinine (Cr) and to quantify the effect of protein intake on postnatal growth in preterm infants. STUDY DESIGN: This is a 4-year, single-center, retrospective cohort study. We used multivariable linear regression models to examine the relationships between mean weekly BUN and protein intake adjusted for mean weekly Cr and potential confounders. We used additional regression models to examine the effect of protein intake on growth during this period. RESULT: Overall, 249 infants met study criteria. As protein intake increased over the first 3 weeks of life, both BUN and Cr decreased significantly. Linear regression models showed protein intake and Cr were each significantly associated with mean BUN for each study week. CONCLUSION: Protein intake and Cr were each significantly associated with BUN. Significant amelioration of growth failure was seen with higher protein intake.

Antenatal antibiotic exposure in preterm infants with necrotizing enterocolitis.

OBJECTIVE: To determine whether an association exists between antenatal antibiotic exposure and incidence of necrotizing enterocolitis (NEC) in low birth weight infants. STUDY DESIGN: A retrospective case-control study was performed on all infants with a diagnosis of NEC born at our institition between 1988 and 2006. Medical histories of all infants with a diagnosis of NEC ≥Bell's stage IIA and matched controls without NEC were reviewed. Maternal and neonatal characteristics were compared using the Mantel-Haenszel chi-square procedure, and logistic regression models were constructed to account for confounding. RESULT: Clinical data for 97 matched pairs were analyzed. The adjusted odds ratio (OR) for antenatal exposure to ampicillin was significantly greater for infants who developed NEC (OR 2.3, 95% confidence interval 1.1, 4.8, P=0.003) than for control infants. CONCLUSION: Infants who developed NEC were more likely to have a history of in utero exposure to ampicillin in the immediate antepartum period than infants who did not develop NEC.

Osteopontin deficiency in rat vascular smooth muscle cells is associated with an inability to adhere to collagen and increased apoptosis.

Osteopontin (OPN) is an extracellular matrix protein that has been implicated in vascular smooth muscle cell (VSMC) adhesion. We have previously described the generation of OPN-deficient VSMC that displayed altered adhesion to collagen. We have examined further the causes and consequences of this altered adhesion. OPN-deficiency was associated with a significant reduction in surface expression of alpha1 and beta1 integrins (mean fluorescence intensity alpha1: OPN-deficient 0.135+/-0.04 vs. control 0.313+/-0.05, p < 0.0001; beta1: OPN-deficient 0.398+/-0.09 vs. control 0.570+/-0.05, p < 0.004). Treatment of normal VSMC with antibody to alpha1 recapitulated the adhesion defect. OPN-deficient cells without collagen exposure had an apoptotic fraction of 1.9%, which increased to 95.7% after 24 hours exposure to collagen. Exogenous OPN added to cultures within 15 minutes of plating restored normal cell adhesion, but did not prevent cells from undergoing apoptosis. Normal VSMC had no detectable apoptosis after 24 hours incubation in suspension, whereas OPN-deficient cells had an apoptotic fraction of 37.5% when incubated in suspension under the same conditions. The data suggest that OPN-deficient VSMC have two distinct abnormalities: an alpha1beta1-mediated inability to adhere normally to collagen and an increased propensity for apoptosis.

Neonatal care of infants with head and neck anomalies.

This article reviews the most common serious head and neck congenital anomalies and traumatic injuries that present at or around the time of birth from the perspective of neonatal caregivers. The focus is on the steps necessary to manage these infants in the delivery room and during the first days of life. An organized multidisciplinary team approach is critical to success.

Gestational age-dependent extravillous cytotrophoblast osteopontin immunolocalization differentiates between normal and preeclamptic pregnancies.

PROBLEM: Normal placentation requires modulation of proliferative cytotrophoblast to an invasive phenotype. Preeclampsia is characterized by failed cytotrophoblast invasion and arterial remodeling. Osteopontin (OPN) is an extracellular matrix protein implicated in cell adhesion, spreading, and invasion. METHOD OF STUDY: To investigate gestational age-related OPN expression, placental immunostaining was performed. To investigate the role of OPN in uteroplacental vascular pathology, placental immunostaining from pregnancies with preeclampsia (n = 12), fetal growth retardation (FGR) (n = 8), or both (n = 4) was compared with gestational age-matched controls (n = 24). RESULTS: In non-preeclamptic pregnancies, OPN immunolocalized to basal plate and intervillous cytotrophoblasts from 24-30 weeks (n = 13). In preeclampsia, OPN immunoreactivity was detected from 24-40 weeks. Cytotrophoblasts from FGR placentas were OPN-positive until 30 weeks, unless preeclampsia accompanied the FGR. In this case, cytotrophoblasts were OPN-positive from 24-40 weeks. CONCLUSIONS: The data suggest a role for OPN in cytotrophoblast invasion of the maternal vasculature/extracellular matrix during non-preeclamptic placentation, and OPN may serve as a marker for placental bed remodeling.

Autocrine secretion of osteopontin by vascular smooth muscle cells regulates their adhesion to collagen gels.

Osteopontin (OPN) is a secreted protein postulated to facilitate vascular smooth muscle cell (VSMC) adhesion and migration. Rat aortic VSMC lines were isolated after infection with recombinant retroviruses harboring OPN sense and antisense constructs. All lines grew normally in monolayer culture. On three-dimensional collagen gels, normal VSMCs and lines containing sense constructs (n=15) or empty vector (n=10) attached to gel and invaded the matrix. Four of five antisense clones did not adhere or invade. Antisense clones had lower OPN levels after stimulation with angiotensin II than sense clones or clones containing the empty vector (antisense, 257+/-102 ng/ml; sense, 473+/-104; vector, 434+/-66). Non-adhering antisense clones had lower mean OPN levels after angiotensin II stimulation (161+/-47 ng/ml) than sense or antisense lines with normal adhesion (486+/-63 ng/ml). The ability to adhere correlated with OPN levels >250 ng/ml. Adhesion and invasion were fully restored with addition of 100 to 200 ng/ml of exogenous OPN and were inhibited in normal VSMCs by incubation with 1 microgram/ml anti-OPN antibody. The autocrine secretion of OPN appears to play an important role in VSMC adhesion, spreading, and invasion.

Identification of lysyl oxidase and other platelet-derived growth factor-inducible genes in vascular smooth muscle cells by differential screening.

BACKGROUND: Atherosclerosis and arterial injury are characterized by vascular smooth muscle cell (VSMC) migration and growth and an increase in synthesis of extracellular matrix. Platelet-derived growth factor (PDGF) has been implicated in these processes. This study was designed to identify additional PDGF-regulated genes in VSMC. EXPERIMENTAL DESIGN: A cDNA library prepared from PDGF-stimulated rat aortic VSMC was screened by differential hybridization to identify clones representing PDGF-inducible genes. The time course of growth factor-induced changes in gene expression was examined by RNA blot hybridization. Assays of protein activity were also performed for selected gene products. RESULTS: Four PDGF-regulated cDNA clones were identified by DNA sequencing. These encoded the extracellular matrix proteins lysyl oxidase (LO), thrombospondin, and osteopontin and the intracellular enzyme lactate dehydrogenase (LDH). Levels of mRNA corresponding to all four genes were low in quiescent VSMC and were markedly induced by PDGF, angiotensin II, and 10% calf serum. The regulation of LO and LDH mRNA by these agonists in VSMC has not been previously reported. LO enzymatic activity in the culture media was increased by approximately equals to 700% after exposure to PDGF. In contrast, LDH activity was not increased by PDGF treatment. CONCLUSIONS: The induction of LO mRNA and its secretion by VSMC is an early event accompanying growth factor stimulation and may contribute to organization of the extracellular matrix.

Prostaglandin E2 induces receptive behaviors in female Xenopus laevis.

The object of this study was to examine the effects of exogenous and endogenous prostaglandin E2 (PGE2) on the sexual behavior of female South African clawed frogs, Xenopus laevis. Ticking and leg extension, which communicate sexual unreceptivity to males, were studied in intact, ovariectomized, and ovariectomized-oviductectomized females. The onset of the PGE2 behavioral effect occurs within 30 sec to 3 min of injection for intact and ovariectomized females; for ovariectomized-oviductectomized females, the latency period for the effect ranges from 10-20 min. PGE2 induced receptivity in doses as low as 0.03 microgram/frog. Injection of the prostaglandin synthesis inhibitors, indomethacin and flurbiprofen (FBP), blocked chorionic gonadotropin- (HCG-) induced behavioral receptivity, suggesting that endogenous prostaglandin synthesis may have a role in regulating female sexual behavior. Flurbiprofen blockade of HCG-induced receptivity was reversed by PGE2 administration, suggesting that FBP's effects are PG synthesis-specific.