Impact of birth weight to placental weight ratio and other perinatal risk factors on left ventricular dimensions in newborns: a prospective cohort analysis

OBJECTIVES

To investigate the association between birth weight to placental weight (BW/PW) ratio, and echocardiographic left ventricle (LV) morphology at birth, while accounting for other relevant perinatal factors.

METHODS

A prospective cohort study was conducted on neonates at NewYork-Presbyterian Brooklyn Methodist Hospital from 2014 to 2018, categorized by their BW/PW percentile. Missing data were imputed with principal component analysis. Chi-squared and one-way analysis of variance were used to compare BW/PW groups and the best regression model was selected using a genetic and backward stepwise algorithm.

RESULTS

We analyzed 827 neonates in three BW/PW groups: small (n=16), normal (n=488), and large (n=323). Placental thickness and smallest diameter were positively correlated with several LV parameters, including inter-ventricular septal thickness during diastole (IVSd) (p=0.002, p<0.001) and systole (IVSs) (p=0.001, p<0.001), LV posterior wall thickness at end of diastole (LVPWd) (p=0.003, p<0.001) and systole (LVPWs) (p<0.001, p<0.001), LV mass (p=0.017, p<0.001), and LV mass/volume (p=0.011, p<0.001). The BW/PW ratio correlated with an increased shortening fraction (estimate=0.29, 95 % CI 0.03-0.55, p=0.027). PW correlated with IVSs (p=0.019), while the longest placental diameter was linked to a decrease in LV internal dimension during diastole (LVIDd) (estimate=-0.07, p=0.039), LV mass (estimate=-0.11, p=0.024), and LV mass/volume (estimate=-0.55, p=0.005).

CONCLUSIONS

This study found that several placental factors, including the BW/PW ratio, can independently affect LV dimension and morphology, highlighting the importance of fetal growth and placental health in the physiological adaptation of the fetal heart. More research is needed to establish causation and inform newborn prevention strategies.

Perinatal factors impacting echocardiographic left ventricular measurement in small for gestational age infants: a prospective cohort study

INTRODUCTION

Infants born small for gestational age (SGA) have an increased risk of developing various cardiovascular complications. While many influencing factors can be adjusted or adapt over time, congenital factors also have a significant role. This study, therefore, seeks to explore the effect of perinatal factors on the left ventricular (LV) parameters in SGA infants, as assessed immediately after birth.

METHODS AND MATERIALS

This single-center prospective cohort study, conducted between 2014 and 2018, involved healthy SGA newborns born > 35 weeks' gestation, delivered at New York-Presbyterian Brooklyn Methodist Hospital, and a gestational age (GA)-matched control group of appropriate for gestational age (AGA) infants. Data analysis was performed using multivariate linear regression in STATA.

RESULTS

The study enrolled 528 neonates, 114 SGA and 414 AGA. SGA infants exhibited a mean GA of 38.05 weeks (vs. 38.54), higher male representation (69.3% vs. 51.5%), lower birth weight (BW) (2318g vs 3381g), lower Apgar scores at birth, and a higher rate of neonatal intensive care unit admission compared to AGA infants (41.2% vs.18.9%; p<0.001). Furthermore, SGA infants were more likely to be born to nulliparous women (63.16% vs. 38.16%; p<0.001), with lower body mass index (BMI) (29.8 vs. 31.7; p=0.004), a lower prevalence of gestational maternal diabetes (GDM) (14.9 % vs. 35.5%; p<0.001), and a higher prevalence of preeclampsia (18.4 % vs. 6.52%; p<0.001). BW was identified as the most significant predictor affecting most LV parameters in this study (p<0.001), except shortening fraction, asymmetric interventricular septal hypertrophy and Inter-ventricular septal thickness/LV posterior wall ratio (IVS/LVPW). Lower GA (coefficient = -0.09, p=0.002), insulin use in GDM (coefficient = 0.39, p=0.014), and low APGAR scores at 1 minute (coefficient = -0.07, p<0.001) were significant predictors of IVS during diastole (R-squared [R2]=0.24). High maternal BMI is marginally associated with LVPW during systole (R2=0.27, coefficient = 0.01, p=0.050), while male sex was a significant predictor of LV internal dimension during diastole (R2=0.29, p=0.033).

CONCLUSION

This study highlights the significant influence of perinatal factors on LV parameters in SGA infants, with BW being the most influential factor. Although LV morphology alone may not predict future cardiovascular risk in the SGA population, further research is needed to develop effective strategies for long-term cardiovascular health management in this population.

Complicated Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) Syndrome History in a 14-Year-Old

BACKGROUND Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome is a drug-induced hypersensitivity reaction that can result in a severe cutaneous adverse drug reaction (SCAR). It is a rare and potentially life-threatening condition that occurs after exposure to sulfonamides, antibiotics, or antiepileptics. Its incidence in children is not established; however, the mortality rate is documented at approximately 10%. DRESS syndrome is believed to result from an interaction between multiple factors, including genetics, abnormalities of metabolism, and reactivation of certain herpes family viruses including EBV and HHV-6. The classic presentation includes fever, rash, and lymphadenopathy. Symptoms begin approximately 3 to 8 weeks after exposure to the offending agent. CASE REPORT We present a unique case of DRESS syndrome in a 14-year-old girl occurring after the ingestion of minocycline and amoxicillin-clavulanic acid (amoxicillin). Identification of the offending agent was complicated by the patient having been on multiple antibiotics within a short timeframe of the initial presentation of symptoms. In addition to swelling and pruritus, the patient experienced vision problems due to papilledema with bilateral hemorrhage. The treatment course was further complicated by a decrease in kidney function, requiring the patient's medication regimen to be adjusted accordingly. CONCLUSIONS This is a unique case of DRESS syndrome demonstrating the potential influence of certain viruses on the severity of its presentation. This case also highlights the need to adjust the steroid regimen to reduce the potentially harmful effects on various organ systems.

Femur Fracture in a Premature Infant: An Unusual Association of Sickle Cell Disease with Osteogenesis Imperfecta

Patient: Female, 1-year-old

Final Diagnosis: Sickle cell anaemia

Symptoms: Fracture

Medication: —

Clinical Procedure: —

Specialty: Hematology • Pediatrics and Neonatology

A Possible Case of Vertical Transmission of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in a Newborn With Positive Placental In Situ Hybridization of SARS-CoV-2 RNA

Little is known about the effects of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the coronavirus disease 2019 (COVID-19) on pregnant mothers and their infants. Moreover, there is no definitive evidence that SARS CoV- 2 can be vertically transmitted from an infected mother to the unborn fetus.

Implementation of Electronic Medical Record Template Improves Screening for Complications in Children with Type 1 Diabetes Mellitus

Objective

Health professionals and patients should follow comprehensive screening guidelines to recognize early signs of long-term complications for insulin-dependent type 1 diabetes mellitus (T1DM). The aim of this study is to demonstrate that utilization of electronic medical record (EMR) templates for diabetes management improves adherence to International Society for Pediatric and Adolescent Diabetes (ISPAD) screening guidelines.

Methods

All patients with T1DM who were seen in the outpatient pediatric endocrine clinic (age 0–22 years old) at an urban community-based community hospital during the 2014 calendar year were enrolled in the study (n=49). A retrospective chart review was performed and audited against ISPAD guidelines. An EMR template and order set was then created based on ISPAD screening guidelines with the aim of improving compliance. The templates were implemented in 2015 (initial phase) and 2016 (maintenance phase) and these data were compared to baseline data. A chi-squared test was performed to analyze the differences between the data using SAS version 9.4 (SAS Institute, Inc). A p-value less than 0.05 was considered significant.

Results

Significant improvements (p< 0.05) in screening guideline adherence from baseline to maintenance phase data were found for annual retinopathy (0% to 45%) and neuropathic foot (0% to 64%) exams, screening for microalbuminuria (49% to 79%), celiac disease (6% to 81%), lipids (63% to 86%), and basic metabolic panel (69% to 88%). Of note, thyroid function testing was also increased, but was not statistically significant between the years.

Conclusion

The utilization of EMR templates and order sets for T1DM are valuable tools to aid medical providers in adhering to ISPAD screening guideline.

Colloidal Silver Ingestion Associated with Leukocytoclastic Vasculitis in an Adolescent Female

Patient: Female, 19

Final Diagnosis: Leukocytoclastic vasculitis

Symptoms: Fatigue • joint • pain • muscle • pain • pruritis • rash

Medication: —

Clinical Procedure: —

Specialty: Dermatology

Diagnosis of Tuberculosis in an Asymptomatic Child, Sibling, and Symptomatic Pregnant Mother in New York City by Tuberculin Skin Testing and the Importance of Screening High-Risk Urban Populations for Tuberculosis

BACKGROUND In 2017, in New York City (NYC), 86% of the cases of tuberculosis (TB) occurred in patients who were born outside the United States (US). This case report illustrates the importance of the use of the tuberculin skin test (TST), and other tests for TB infection (TTBI), in screening high-risk groups, the challenges of diagnosing TB in young children, and highlights the importance of preventing a delay in the diagnosis of TB in family members. CASE REPORT Following a routine TST in an asymptomatic 10-year-old girl, a diagnosis of TB was made, which was confirmed on chest X-ray (CXR) and by the presence of acid-fast bacilli (AFB) in the sputum. Her family had emigrated from China to NYC ten years previously. All the family was screened using the TST, which was positive in her 2-year-old sister and her 37-year-old pregnant mother, and pulmonary TB was confirmed on CXR and by AFBs in the sputum. All three family members and the newborn baby were treated according to current guidelines, with a good clinical outcome. CONCLUSIONS This case report raises awareness about the lack of symptoms in childhood TB and the importance of screening high-risk patients in an urban immigrant population. In children under 5 years of age, a diagnosis of TB can indicate a sentinel event, suggesting a potential undiagnosed or untreated source case, which is usually an adult family member. This report highlights the challenges of diagnosing TB in children, who may be asymptomatic with negative laboratory findings.

Video didactic at the point of care impacts hand hygiene compliance in the neonatal intensive care unit (NICU)

OBJECTIVE

To increase the hand-washing (HW) duration of staff and visitors in the NICU to a minimum of 20 seconds as recommended by the CDC.

METHODS

Intervention included video didactic triggered by motion sensor to play above wash basin. Video enacted Centers for Disease Control and Prevention (CDC) HW technique in real time and displayed timer of 20 seconds. HW was reviewed from surveillance video. Swabs of hands plated and observed for qualitative growth (QG) of bacterial colonies.

RESULTS

In visitors, the mean HW duration at baseline was 16.3 seconds and increased to 23.4 seconds at the 2-week interval (p = .003) and 22.9 seconds at the 9-month interval (p < .0005). In staff, the mean HW duration at baseline was 18.4 seconds and increased to 29.0 seconds at 2-week interval (p = .001) and 25.7 seconds at the 9-month interval (p < .0005). In visitors, HW compliance at baseline was 33% and increased to 52% at the 2-week interval (p = .076) and 69% at the 9-month interval (p = .001). In staff, HW compliance at baseline was 42% and increased to 64% at the 2-week interval (p = .025) and 72% at the 9-month interval (p = .001). Increasing HW was significantly associated with linear decrease in bacterial QG.

CONCLUSIONS

The intervention significantly increased mean HW time, compliance with a 20-econd wash time and decreased bacterial QG of hands and these results were sustained over a 9-month period.

Perspectives and attitudes of pediatricians concerning post-discharge care practice of premature infants

OBJECTIVE

Survival rates of premature infants are at a historical high and increasingly more pediatricians are caring for former premature infants. The goal of this study was to describe the perspectives and attitudes of pediatricians, as well as, the challenges of rendering post-neonatal intensive care unit (NICU) discharge care for premature infants.

METHODS

An anonymous 22-question web-based survey was emailed to pediatricians who are current members of the American Academy of Pediatrics (AAP) and practicing in Kings County, New York.

RESULTS

There were 148 completed surveys with 79% being general pediatricians. Of all respondents, 63% believed that premature infants should have a neonatal high risk follow-up visit within days after discharge and 64% were satisfied with the NICU discharge summary acquisition. While 74% of pediatricians felt comfortable following up with former extremely premature infants, 65% referred to specialists, most often to child development, neurology, and physical and/or occupational therapy. The majority (85%) were more likely to refer premature infants to early intervention. Participating pediatricians varied in their knowledge of immunization and breastfeeding guidelines. Finally, 88% of respondents acknowledged that caregivers of premature infants experience increased stress, with 53% stating that the stress should be addressed.

CONCLUSIONS

Understanding the perceptions and challenges of pediatricians who care for premature infants may help improve post NICU quality of care. Transition to the outpatient setting is a crucial step in the management of premature infants and a focus on improved hand-off procedures between hospital and physicians may prove beneficial. Also, pediatricians must stay abreast of current recommendations for breastfeeding and vaccinations. Furthermore, emphasis should be given to stress reduction and management for caregivers of former premature infants.

The association between placental histopathology and autism spectrum disorder

INTRODUCTION

Research suggests that autism spectrum disorder (ASD) has its origins in utero. This study examines the association between evidence of placental histopathology and ASD.

METHODS

Administrative claims data and medical records data were used to identify ASD cases (N = 55) and matched controls (N = 199) born at New York Methodist Hospital between 2007 and 2014 and subsequently seen in affiliated pediatrics clinics. Placentas from all births during this time period were reviewed as part of routine care. Data were analyzed using conditional logistic regression to account for the matched (gender, gestational age, and birth weight) design.

RESULTS

Acute placental inflammation, regardless of type was associated with an increased risk of ASD (odds ratio [OR] = 3.14, 95% CI = 1.39, 6.95). Chronic uteroplacental vasculitis (OR = 7.13; 95% CI = 1.17, 43.38), the fetal inflammatory response in the chorionic plate vessels (OR = 5.12; 95% CI = 2.02, 12.96), and maternal vascular malperfusion pathology (OR = 12.29; 95% CI = 1.37, 110.69) were associated with an increased risk of ASD. Placental villous edema was associated with a decreased risk of ASD (OR = 0.05; 95% CI = 0.0005, 0.42). In subanalyses among male placentas acute inflammation overall, fetal inflammatory response in the chorionic plate vessels, and maternal vascular malperfusion pathology remained significantly associated with an increased risk of ASD whereas placental villous edema remained associated with a decreased risk of ASD.

DISCUSSION

Histologic evidence of placental inflammation and maternal vascular malperfusion pathology are associated with ASD.

Effectiveness of Early Antiviral Therapy in Disseminated Neonatal Herpes Simplex Virus 2 (HSV-2) with Fulminant Hepatic Failure

Patient: Male, 11-day-old

Final Diagnosis: Disseminated neonatal herpes simplex virus-2

Symptoms: Feeding problems • lethargy • rash

Medication: —

Clinical Procedure: —

Specialty: Pediatrics and Neonatology

Physician Transition of Care: Benefits of I-PASS and an Electronic Handoff System in a Community Pediatric Residency Program

BACKGROUND

Miscommunication is a leading cause of adverse events in hospitals. Optimizing the handoff process improves communication and patient safety. We sought to assess how the components of I-PASS (a mnemonic for illness severity, patient summary, action list, situational awareness with contingency planning, and synthesis by the receiver), a standardized handoff bundle, improved the quality of handoffs in a pediatric residency program based in a community hospital.

METHODS

Pediatric residents in a university-affiliated community teaching hospital were observed on the pediatric inpatient floor and in the newborn nursery. One hundred resident handoffs per setting were analyzed in 3 phases, with a total of 600 handoffs assessed. Phase 1 comprised preintervention handoffs before I-PASS; phase 2, initiating I-PASS mnemonic and educational session; and phase 3, implementing a handoff tool, electronic physician handoff (EPH), into the electronic medical record. One attending physician at each setting assessed the handoff process using an 11-item survey. A resident satisfaction survey assessed the resident's experience after phase 3.

RESULTS

Comparing phase 1 with phase 2, there was improved situational awareness with contingency planning (nursery: 12% to 83%, P = .001; floor: 21% to 84%, P = .001). Incidence of tangential conversation decreased in both settings (nursery: 100% to 23%, P = .001; floor: 84% to 11%, P = .001). Comparing phase 2 with phase 3, there was improvement in identification of illness severity (nursery: 62% to 99%, P = .001; floor: 41% to 64%, P = .001) and fewer omissions of important information (nursery: 14% to 0%, P = .001; floor: 33% to 17%, P = .007). A total of 93% of residents found the new EPH system to be beneficial.

CONCLUSIONS

Specific components of a standardized handoff system, including a mnemonic, an educational intervention, and an EPH, improved the clarity and organization of key information in handoff.

Prominent Eustachian Valve in Newborns: A Report of Four Cases

The Eustachian valve (EV) is an embryological remnant of the inferior vena cava that during fetal life helps divert oxygenated blood from the IVC toward the foramen ovale to escape the pulmonary circulation. This remnant usually regresses after birth and is considered a benign finding in the majority of cases. However, EV can lead to complications in the neonatal period or later in life. In this short case series, we present four newborn infants with prominent EV who were symptomatic after birth and required admission to the neonatal intensive care unit.

Increasing maternal body mass index during pregnancy increases neonatal intensive care unit admission in near and full-term infants

BACKGROUND

Obesity is becoming an increasingly commonplace health problem. Obesity during pregnancy is important because the condition adversely affects not only the mother, but also the developing fetus and the newborn.

OBJECTIVE

The primary objective of this study was to evaluate the association between maternal body mass index (mBMI) at the time of delivery and neonatal intensive care unit (NICU) admission of offspring and to analyze the role of possible confounding variables that are often associated with obesity. Comorbidities, such as gestational diabetes mellitus (DM), hypertension (HT) and/or pre-eclampsia (PEC), are more common in more obese mothers, as is a higher association of obesity among non-Caucasian patients.

METHODS

Using a retrospective cohort design, 1736 mothers and their singleton live-born at  ≥35 weeks' gestation were analyzed for mBMI, maternal conditions of DM, HT and/or PEC, and whether NICU care was required and the reason for NICU admission.

RESULTS

NICU admission rate was significantly associated with maternal obesity. In comparing women with mBMI  < 30 versus mBMI ≥ 30, OR was 1.39 (p = 0.045); OR increased to 1.76 (p = 0.006) in comparing patients with mBMI  ≥ 35. mBMI was significantly associated with an increased rate of maternal DM, HT and PEC (p < 0.05 each); however, NICU admission rate was not correlated with DM, HT or PEC. The relationship between NICU admission and mBMI was significant in Caucasian mothers versus a borderline significance in African-American mothers (p = 0.035 versus p = 0.05). After controlling for neonatal hypoglycemia (NH) as the reason for admission to the NICU, no mBMI-NICU association persisted. The rate of infants with NH increased in higher mBMI groups, independent of maternal DM diagnosis.

CONCLUSION

This study demonstrated a significant association between higher mBMI groups and NICU admissions independent of diagnosis of maternal comorbidities. However, accounting for NH eliminating this association suggests a pre-clinical diabetic pathology in obese women that affects newborn outcome. Despite increased percentage of nonwhite mothers in higher mBMI groups, African-American race does not seem to be a significant contributing factor in the increased rate of NICU admission in our population.

Abrin poisoning in an 18-month-old child

Patient: Male, 1

Final Diagnosis: Abrin poisoning

Symptoms: Abdominal pain • diarrhea • vomiting

Medication: —

Clinical Procedure: —

Specialty: Pediatrics and Neonatology

Histologic chorioamnionitis as a consideration in the management of newborns of febrile mothers

INTRODUCTION

Chorioamnionitis (CA) presents a risk for neonatal sepsis, but its diagnosis remains a challenge. Maternal fever is often used as a clinical predictor of infection, but may be affected by other factors. There is no consensus among neonatologists regarding the length of treatment of babies born to febrile mothers with negative blood culture, but whose placentas are positive for the presence of histologic CA (HCA).

OBJECTIVES

A prospective observational cohort study was conducted on term infants to determine the association of HCA with C-reactive protein (CRP) and elevated immature/total neutrophil (I/T) ratio and other perinatal factors.

METHODS

I/T ratio, CRP, blood culture and placental pathology were performed on 100 infants born to mothers with temperature ≥ 100.4 °F. Placental pathology performed on 100 control infants born to afebrile mothers.

RESULTS

There was a significant association between HCA and maternal fever (MF). The presence of elevated CRP was associated with HCA. There was no significant association between HCA and anesthesia, mode of delivery, nor elevated I/T ratio.

CONCLUSIONS

Maternal fever is associated with HCA. The HCA in conjunction with an elevated CRP can guide the duration of antimicrobial therapy in infants born to febrile mothers.

Chorea and developmental regression associated with human herpes virus-6 encephalitis

We report a 14-month old child with multiple episodes of febrile status epilepticus, followed by chorea and developmental regression, caused by human herpes virus-6 encephalitis. Chorea has been described as a complication of relapsing herpes simplex virus I infection, but not as a manifestation of human herpes virus-6 infection. It is uncertain whether the chorea was an autoimmune phenomenon or a direct effect of the virus. The child was treated with levetiracetam, intravenous immunoglobulin, and foscarnet. The seizures and chorea resolved with treatment, but developmental regression, with loss of language skills, persisted 6 months after the illness. This child illustrates a new clinical presentation of human herpes virus-6 encephalitis, adds to the spectrum of disorders caused by this virus, and strengthens the case for routine identification of specific viral agents in all cases of childhood viral infections with central nervous system symptoms to determine optimal treatment and prognosis.

Suppression of nuclear factor-kappa B activity by nitric oxide and hyperoxia in oxygen-resistant cells

Inhaled nitric oxide (iNO) is used clinically to treat pulmonary hypertension in newborns, often in conjunction with hyperoxia (NO/O2). Prolonged exposure to NO/O2 causes synergistic lung injury and death of lung epithelial cells. To explore the mechanisms involved, oxygen-resistant HeLa-80 cells were exposed to NO +/- O2. Exposure to NO and O2 induced a synergistic cytotoxicity, accompanied with apoptotic characteristics, including elevated caspase-3-like activity, Annexin V incorporation, and nuclear condensation. This apoptosis was associated with a synergistic suppression of NF-kappaB activity. Cells lacking functional NF-kappaB p65 subunit were more sensitive to NO/O2 than their wild type counterparts. This injury was partially rescued by transfection with a p65 expression construct, suggesting an inverse relationship between NF-kappaB and susceptibility to the cytotoxicity of NO/O2. Despite the reduced NF-kappaB activity in cells exposed to NO +/- O2, IkappaBalpha was degraded, suggesting that pathways regulating the steady-state levels of IkappaB were not involved. However, exposure to NO/O2 caused a marked reduction in nuclear localization and an increase in protein carbonyl formation of NF-kappaB p65 subunit. These results suggest that NO/O2-induced apoptosis occurs by suppressing NF-kappaB activity.

Issues in neonatal and pediatric oxygen therapy

This article reviews the complex physiology of oxygen transport in the fetus and neonate, and how it differs from the older pediatric patient and adult. The common causes of respiratory distress unique to the neonatal and pediatric populations are reviewed in detail, including a brief discussion regarding the different modes of mechanical ventilation used in neonates. The increased susceptibility of infants to the toxic effects of oxygen is reviewed.

Synergistic cytotoxicity from nitric oxide and hyperoxia in cultured lung cells

Exogenous nitric oxide (NO) is being tested clinically for the treatment of pulmonary hypertension in infants and children. In most cases, these patients receive simultaneous oxygen (O2) therapy. However, little is known about the combined toxicity of NO + hyperoxia. To test this potential toxicity, human alveolar epithelial cells (A549 cells) and human lung microvascular endothelial lung cells were cultured in room air (control), hyperoxia (95% O2), NO (derived from chemical donors), or combined hyperoxia + NO. Control cells grew normally over a 6-day study period. In contrast, cell death from hyperoxia was evident after 4-5 days, whereas cells neither died nor divided in NO alone. However, cells exposed to both NO and hyperoxia began to die on day 2 and died rapidly thereafter. This cytotoxic effect was clearly synergistic, and cell death did not occur via apoptosis. As an indicator of peroxynitrite formation, nitrotyrosine-containing proteins were assayed using anti-nitrotyrosine antibodies. Two protein bands, at molecular masses of 25 and 35 kDa, were found to be increased in A549 cells exposed to NO or NO + hyperoxia. These results indicate that combined NO + hyperoxia has a synergistic cytotoxic effect on alveolar epithelial and lung vascular endothelial cells in culture.

Recombinant human superoxide dismutase reduces lung injury caused by inhaled nitric oxide and hyperoxia

We previously demonstrated that 48 h of 100 ppm inhaled nitric oxide (NO) and 90% O2 causes surfactant dysfunction and pulmonary inflammation in mechanically ventilated newborn piglets. Because peroxynitrite (the product of NO and superoxide) is thought to play a major role in the injury process, recombinant human superoxide dismutase (rhSOD, a scavenger of superoxide) might minimize this insult. Four groups of newborn piglets (1-3 days of age) were ventilated with 100 ppm NO and 90% O2 for 48 h. Piglets received no drug, 5 mg/kg rhSOD intratracheally at time 0, 5 mg/kg rhSOD intratracheally at 0 and 24 h, or 10 mg/kg rhSOD by nebulization at time 0. At 48 h, bronchoalveolar lavage (BAL) was performed, and lung tissue was analyzed for markers of inflammation, oxidative injury, acute lung injury, and surfactant function. There were significant differences between rhSOD-treated piglets and untreated controls with respect to BAL neutrophil chemotactic activity, cell counts, and protein concentration as well as lung tissue malondialdehyde concentrations. Minimum surface tension of BAL surfactant from all groups studied was increased, with no differences found among groups. These data suggest that rhSOD, at the doses used, mitigated the inflammatory changes, oxidative damage, and acute lung injury from exposure to 100 ppm NO and 90% O2 but did not appear to improve surfactant function. This has important clinical implications for infants treated with hyperoxia and NO for neonatal lung disorders.

alpha,beta-Dehydro-amino acid residues in the design of peptide structures: synthesis, crystal structure, and molecular conformation of two homologous peptides-N-Ac-dehydro-Phe-L-Leu-OCH3 and N-Ac-dehydro-Phe-NorVal-OCH3

The dehydro-residue containing peptides N-Ac-dehydro-Phe-L-Leu-OCH3 (I) and N-Ac-dehydro-Phe-NorVal-OCH3 (II) were synthesized by the usual workup procedures. The peptides crystallize from their solutions in methanol in space group P6(5): (I) a = b = 12.528(2) A, c = 21.653(5) A; (II) a = b = 12.532(2) A, c = 21.695(4) A. The structures were determined by direct methods. Both peptides adopt similar conformations with phi,psi of dehydro-Phe as follows: (I) -57.0(5) degrees and -37.0(5) degrees; (II) -56.0(5), degrees, and -37.5(5) degrees. The observed data on dehydro-Phe when placed at the (i + 1) position show that the phi,psi values of dehydro-Phe are either -60 degrees, 140 degrees or -60 degrees, -30 degrees. The conformation of -60 degrees, 140 degrees can be accommodated only with a flexible residue at the (i + 2) position while the phi,psi values of -60 degrees, -30 degrees are obtained with a bulky residue at the (i + 2) position as in the present structures. The molecules are packed in a helical way along the c axis. These are held by two strong intermolecular hydrogen bonds involving both NH as donors and acetyl group and dehydro-Phe oxygen atoms as acceptors.

Molecular design of peptides. Synthesis, molecular structure and beta-turn II' formation of N-Boc-L-Phe-dehydro-Abu-NH-CH3 in crystals

The peptide N-Boc-L-Phe-dehydro-Abu-NH-CH3 was synthesized by the usual workup procedure. The crystals grown from methanol at 4 degrees C belong to the space group P2(1)2(1)2(1) with a = 7.589(2), b = 13.690(4), c = 21.897(6) A, Z = 4 and dc = 1.149(5) g cm-3 for C19H29N3O5.CH3OH. The peptide crystals were highly sensitive to radiation. The final agreement factor R was 0.055 for 1109 observed reflections (I > or = 2 sigma) with data extending to a 2 theta value of 103 degrees. The methanol oxygen atom is split into two occupancies. Both sites are involved in identical hydrogen bonding. As a result of substitution of a dehydro-Abu residue at the (i + 2) position the peptide adopts an ideal beta-turn II' conformation with torsion angles of corner residues as phi 1 = 63(1) degrees, psi 1 = -127(1) degrees, phi 2 = -66(1) degrees and psi 2 = -10(1) degrees, and an intramolecular hydrogen bond N-H...O of length 3.01(1) A. This shows that the conformational constraints produced by dehydro-Abu are similar in nature to but different in magnitude than those produced by dehydro-Phe and dehydro-Leu. The methanol-peptide interactions show characteristic features of multiple hydrogen-bond formations involving polar sites of participating peptide and methanol molecules. The packing of the molecules in the unit cell is stabilized by interactions through methanol molecules with the help of several hydrogen bonds.

Fluid transport across cultured bovine corneal endothelial cell monolayers

The mammalian corneal endothelium is known to transport fluid from the stromal compartment to the aqueous humor, thereby maintaining corneal transparency. Corneal endothelial cells have been cultured for some years now, but whether they preserve their in vivo ability to actively transport fluid is not known. We have now grown bovine corneal endothelial cell monolayers (BCECM) on permeable substrates (Transwell) and report that, just like their counterparts in vivo, these cultured cells pump fluid from the basal to the apical compartment and display measurable electrical resistance and potential difference across the monolayer. BCECM were grown on collagen-treated permeable supports using Dulbecco's modified Eagle's medium (DMEM)/20% fetal bovine serum with antibiotics. Cells grew to confluence in 5-7 days and displayed polygonal shape. Only cells from passages 1-3 were utilized. Inserts were fitted directly into Lucite chambers specially built. The rate of fluid pumping by BCECM was 3.96 +/- 0.49 (SE) microliter.h-1.cm-2 (n = 13) and could be measured continuously for several hours; fluid pumping was inhibited by 0.2 mM amiloride. The specific electrical resistance of the monolayers was 180 +/- 22 omega.cm2 (n = 11). A mean electrical potential difference of 63.8 +/- 3.7 microV (n = 15, range 40-100 microV, apical side negative) was recorded across the monolayers in DMEM. The availability of the commercial inserts makes this procedure practical; as a consequence, the rate of fluid transport by cultured corneal endothelium has been quantitated for the first time. This method can now be extended to other cultured layers.(ABSTRACT TRUNCATED AT 250 WORDS)

Synthesis, crystal structure, and molecular conformation of N-Ac-dehydro-Phe-L-Val-L-Val-OCH3

The peptide N-Ac-dehydro-Phe-L-Val-L-Val-OCH3 (C22H31N3O5) was synthesized by the usual workup procedure and finally by coupling the N-Ac-dehydro-Phe-L-Val-OH to valine methyl ester. It was crystallized from its solution in acetonitrile-water mixture at 4 degrees C. The crystals belong to the space group P1 with a = 8.900(3) A, b = 11.135(2) A, c = 12.918(2) A, alpha = 90.36(1) degrees, beta = 110.14(3) 14(3) degrees, V = 1207.7(6) A, 3Z = 2, dm = 1.156(5) Mgm-3, dc = 1.148(5) Mgm-3. The structure was determined by direct methods using SHELXS86. The structure was refined by full-matrix least-squares procedure to an R value of 0.077 for 3916 observed reflections. The molecular dimensions and conformations of the two crystallographically independent molecules are in good agreement. In the dehydro residues, the average C alpha-C beta distance is 1.31(2) A whereas the bond angle C alpha-C beta-C gamma is 132(1) degrees. The average backbone torsion angles are omega 0 = 169(1) degrees, phi 1 = -40(1) degree, psi 1 = -50(1) degree, omega 1 = -177(1) degree, phi 2 = 54(1) degree, psi 2 = 46(1) degree, omega 2 = -174(1) degree, phi 3 = 103(1) degree, psi T3 = -139(1) degree, and theta T3 = -176(1) degree. The acetyl group is in the trans conformation, while the backbone adopts a right-handed and left-handed helical conformation alternatingly.(ABSTRACT TRUNCATED AT 250 WORDS)

Impact of pediatricians' attire on children and parents

To evaluate perceptions of a pediatrician's attire, 50 children and parents in an outpatient facility were shown five photographs of a female or a male physician dressed differently (formal to informal). A list of positive and negative attributes was presented to the parents and children who were to match each picture to the attributes. Parents had a strong positive preference for the formally dressed female (short white coat and skirt), and the formally dressed male (short white coat and tie). More than 50% of the parents least preferred the most informal attire. Children had no clear preferences for males and preferred the female in the blouse and skirt. Children assigned negative attributes to informal attire but not to the same degree as did their parents. This study demonstrates that parents have stronger preferences than do their children. Although children had no strong positive preferences, they may feel negatively about informal attire.

Alpha,beta-dehydro residues in the design of peptide and protein structures

The results of X-ray studies on 19 structures containing dehydro residues have been analysed. The observed average C alpha = C beta distance in the dehydro residues is 1.331 (2) A. The average values of the C alpha = C beta - C gamma bond angle in dehydro-Phe and dehydro-Leu are 131.2 (2) and 127.3 (1) degrees, respectively. The dehydro residue is essentially planar. A beta-turn of type II is formed if the dehydro residue is placed either at the (i + 1) or at the (i + 2) corner position of the beta-turn. If the dehydro residues occur consecutively in an amino-acid sequence, the backbone folds into an alternating right- and left-handed alpha-helix. The peptide bond is planar in all these structures. The beta-turn is stabilized by an intramolecular hydrogen bond between CO of the ith and NH of the (i + 3)th residue.

Synthesis, crystal structure, and molecular conformation of N-Boc-L-Phe-dehydro-Leu-L-Val-OCH3

The peptide N-Boc-L-Phe-dehydro-Leu-L-Val-OCH3 was synthesized by the usual workup procedure and finally by coupling the N-Boc-L-Phe-dehydro-Leu-OH to valine methyl ester. It was crystallized from its solution in methanol-water mixture at 4 degrees C. The crystals belong to the triclinic space group P1 with a = 5.972(5) A, b = 9.455(6) A, c = 13.101(6) A, alpha = 103.00(4) degrees, beta = 97.14(5) degrees, gamma = 102.86(5) degrees, V = 690.8(8) A, Z = 1, dm = 1.179(5) Mg m-3 and dc = 1.177(5) Mg m-3. The structure was determined by direct methods using SHELXS86. It was refined by block-diagonal least-squares procedure to an R value of 0.060 for 1674 observed reflections. The C alpha 2-C beta 2 distance of 1.323(9) A in dehydro-Leu is an appropriate double bond length. The bond angle C alpha-C beta-C gamma in the dehydro-Leu residue is 129.4(8) degrees. The peptide backbone torsion angles are theta 1 = -168.6(6) degrees, omega 0 = 170.0(6) degrees, phi 1 = -44.5(9) degrees, psi 1 = 134.5(6) degrees, omega 1 = 177.3(6) degrees, phi 2 = 54.5(9) degrees, psi 2 = 31.1(10) degrees, omega 2 = 171.7(6) degrees, phi 3 = 51.9(8) degrees, psi T3 = 139.0(6) degrees, theta T = -175.7(6) degrees. These values show that the backbone adopts a beta-turn II conformation. As a result of beta-turn, an intramolecular hydrogen bond is formed between the oxygen of the ith residue and NH of the (i + 3)th residue at a distance of 3.134(6) A.(ABSTRACT TRUNCATED AT 250 WORDS)

Crystal structure and molecular conformation of the peptide N-Boc-L-Gly-dehydro-Phe-NHCH3

The peptide N-Boc-L-Gly-dehydro-Phe-NHCH3 was synthesized by the combination of N-Boc-L-Gly-dehydro-Phe azlactone and methylamine. The peptide crystallizes in orthorhombic space group P2(1)2(1)2(1) with a = 5.679(2) A, b = 16.423(9) A, c = 19.198(10) A, V = 1791(2) A3, Z = 4, dm = 1.212(5) Mg m-3, dc = 1.237(1) Mg m-3. The structure was determined by direct methods using SHELXS 86. The structure was refined by full-matrix least squares procedure to an R value of 0.049 for 1509 observed reflections. The molecular dimensions are, in general, in good agreement with the standard values. The bond angle C alpha-C beta-C gamma in the dehydro-Phe residue is 133.6(5) degrees. The peptide backbone torsion angles are theta 1 = -171.4(4) degrees, omega 0 = 178.2(4) degrees, phi 1 = -57.2(6) degrees, psi 1 = 141.2(4) degrees, omega 1 = -174.4(4) degrees, phi 2 = 71.5(6) degrees, psi 2 = 7.2(6) degrees, and omega 2 = -179.8(5) degrees. These values show that the backbone adopts the beta-bend type II conformation. The Boc group has a trans-trans conformation. The side-chain torsion angles in dehydro-Phe are chi 2 = 1.6(9) degrees, chi 2(2, 1) = 0.5(9) degrees, and chi 2(2, 2) = 179.8(6) degrees. The plane of C2 alpha-C2 beta-C2 gamma is rotated with respect to the plane of the phenyl ring at 0.5(6) degrees, which indicates that the atoms of the side chain of the dehydro-Phe residue are essentially coplanar.(ABSTRACT TRUNCATED AT 250 WORDS)