Effects of antioxidant MnTBAP on angiogenesis in newborn mice with hyperoxic lung injury.

BACKGROUND: Oxygen toxicity mediated by reactive oxygen species (ROS) plays an essential role in the development of bronchopulmonary dysplasia in premature infants. By reducing oxidative stress, antioxidants protect the immature lung. We studied the effects of MnTBAP, a catalytic antioxidant on angiogenesis and alveolar growth following neonatal hyperoxia. METHODS: Newborn mouse litters randomized to room air (RA) or >95% O2 for 72 hours from day 4 (D4) to D7 to receive either MnTBAP (10 mg/kg/d) or saline intraperitoneally (every 24 h for three doses). Lungs harvested for angiogenic gene expression, protein expression, and histopathology post-hyperoxia exposure. Radial alveolar count (RAC), mean linear intercept (MLI) and vessel density assessed by histopathology. RESULTS: Angiogenic gene expression was significantly lower in the hyperoxia group compared to the RA group. The protein expression for VEGF and its receptor, VEGFR1, was significantly lower following treatment with MnTBAP compared to hyperoxia alone. Expression of VEGFR2, Angiopoietin-1 and TIE2, were substantially higher in the RA groups compared to hyperoxia groups with or without MnTBAP. Hyperoxia groups demonstrated alveolar simplification. MnTBAP reduced vessel density and failed to improve alveolar growth following hyperoxia. CONCLUSIONS: MnTBAP, a catalytic antioxidant, does not offer protection from hyperoxia-induced alveolar impairment. The lack of angiogenic upregulation by MnTBAP may contribute to alveolar simplification in newborn mice.

Stridor in infants with hypoxic-ischemic encephalopathy and whole body hypothermia: A case series.

BACKGROUND: Stridor is one of the rare side effects of neonatal hypothermia treatment for hypoxic-ischemic encephalopathy. We aimed to describe the clinical characteristics of the infants who underwent whole-body hypothermia and developed stridor. METHODS: We reviewed the medical records of 171 infants with moderate or severe hypoxic-ischemic encephalopathy who underwent hypothermia therapy. Demographics, as well as clinical characteristics, were documented. RESULTS: A total of 18 infants developed transient stridor out of 171 infants who underwent whole-body hypothermia (10.5%). The stridor was transient and resolved in all infants. All infants with stridor received treatment with one or more of the following: racemic epinephrine, dexamethasone, positive pressure ventilation and/or heliox. Two infants required otorhinolaryngologist (ENT) evaluation due to persistent and severe symptoms, of whom one was found to have left vocal cord paresis that improved with time. CONCLUSION: Stridor is a transient complication associated with hypoxic-ischemic encephalopathy and whole-body hypothermia in neonates. The exact mechanism is unclear and most likely multifactorial. ENT evaluation is recommended in the presence of prolonged symptoms or significant respiratory distress.

Early onset necrotizing enterocolitis (NEC) in premature twins.

Twin infants born at 34 week gestation had frank blood in stools on day three of life on mixed feeds of formula and maternal breast milk. Sepsis work up was negative in these relatively well appearing infants with pneumatosis in the colon on abdominal x-ray. Blood in stools recurred on reintroduction of breast milk in Twin A. Both infants recovered from episodes of bloody stools on amino-acid based formula and were thriving at discharge. Early necrotizing enterocolitis in both twins is rare and has not been reported. Cow's milk protein sensitivity, possibly from in-utero sensitization, could explain non-infectious colitis in these twins, precipitated by formula or breast milk after birth.

Retention of denture bases fabricated by three different processing techniques - An in vivo study.

AIM: Distortion due to Polymerization shrinkage compromises the retention. To evaluate the amount of retention of denture bases fabricated by conventional, anchorized, and injection molding polymerization techniques. MATERIALS AND METHODS: Ten completely edentulous patients were selected, impressions were made, and master cast obtained was duplicated to fabricate denture bases by three polymerization techniques. Loop was attached to the finished denture bases to estimate the force required to dislodge them by retention apparatus. Readings were subjected to nonparametric Friedman two-way analysis of variance followed by Bonferroni correction methods and Wilcoxon matched-pairs signed-ranks test. RESULTS: Denture bases fabricated by injection molding (3740 g), anchorized techniques (2913 g) recorded greater retention values than conventional technique (2468 g). Significant difference was seen between these techniques. CONCLUSIONS: Denture bases obtained by injection molding polymerization technique exhibited maximum retention, followed by anchorized technique, and least retention was seen in conventional molding technique.

To Evaluate the Bone Mineral Density in Mandible of Edentulous Patients using Computed Tomography: An In Vivo Study.

BACKGROUND: To evaluate the bone mineral density in the mandible of edentulous patients at prospective intraoral implant sites. Pre-operative evaluation of bone density is essential to assist the clinician with the treatment planning of implant supported prosthesis. MATERIALS AND METHODS: A study group of 12 edentulous subjects comprising of six male and six female between the age group of 45-55 years seeking implant supported prosthesis were selected. A radiographic stent using auto polymerizing resins incorporating the gutta-percha cones were prepared for the computed tomography scan. The bone mineral density values were recorded in various sites (trabecular and cortical) of the mandibular jaws in Hounsfield units. The data thus obtained were tabulated and statistically analyzed using Mann-Whitney U-test and Kruskal-Wallis test. RESULTS: The bone mineral density in the buccal cortical region of mandible increases from incisors to molars and in the trabecular region it is more in the incisors and canines compared to the premolar and molar regions whereas in the lingual cortical region of mandible may lie on nearly the same level over the entire lingual cortex. The bone mineral density is little higher in males than females. CONCLUSION: There is variation in the bone mineral density in the buccal cortex and trabecular bone, but no significant variation in the lingual cortex when compared between male and female subjects.

Comparative Evaluation of Tensile Bond Strength between Silicon Soft Liners and Processed Denture Base Resin Conditioned by Three Modes of Surface Treatment: An Invitro Study.

Soft denture liners act as a cushion for the denture bearing mucosa through even distribution of functional load, avoiding local stress concentrations and improving retention of dentures there by providing comfort to the patient. The objective of the present study was to compare and evaluate the tensile bond strengths of silicone-based soft lining materials (Ufi Gel P and GC Reline soft) with different surface pre treatments of heat cure PMMA denture base acrylic resin. Stainless steel dies measuring 40 mm in length; 10 mm in width and 10 mm in height (40 × 10 × 10) were machined to prepare standardized for the polymethyl methacrylate resin blocks. Stainless steel dies (spacer for resilient liner) measuring 3 mm thick; 10 mm long and 10 mm wide were prepared as spacers to ensure uniformity of the soft liner being tested. Two types of Addition silicone-based soft lining materials (room temperature polymerised soft lining materials (RTPSLM): Ufi Gel P and GC Reline soft) were selected. Ufi Gel P (VOCO, Germany), GC Reline soft (GC America) are resilient, chairside vinyl polysiloxane denture reliners of two different manufacturers. A total of 80 test samples were prepared of which 40 specimens were prepared for Group A (Ufi Gel P) and 40 specimens for Group B (GC Reline soft). In these groups, based on Pre-treatment of acrylic resin specimens each group was subdivided into four sub groups of 10 samples each. Sub-group I-without any surface treatment. Sub-group II-sand blasted Sub-group III-treated with Methyl Methacrylate monomer Sub-group IV-treated with chemical etchant Acetone. The results were statistically analysed by Kruscal Wallis test, Mann-Whitney U test, and Independent t test. The specimens treated with MMA monomer wetting showed superior and significant bond strength than those obtained by other surface treatments. The samples belonging to subgroups of GC Reline soft exhibit superior tensile bond strength than subgroups of Ufi Gel P. The modes of failure of all specimens were mostly adhesive in nature. Surface pre treatments by chemical means improved the bond strength between the silicone liners and denture base.

Methemoglobin to cumulative nitric oxide ratio and response to inhaled nitric oxide in PPHN.

BACKGROUND: One-third of infants with persistent pulmonary hypertension of the newborn (PPHN) do not respond to inhaled nitric oxide (iNO). If iNO is not delivered to the pulmonary vasculature because of parenchymal lung disease, it cannot interact with hemoglobin to form methemoglobin (MHb). OBJECTIVE: To study the correlation between oxygenation response to iNO in infants with PPHN secondary to parenchymal lung disease and initial MHb% to cumulative NO exposure (ppm x hours) ratio (MHb/SigmaNO). STUDY DESIGN: Retrospective chart review of neonates with PPHN secondary to parenchymal lung disease treated with iNO comparing non-responders (PaO(2)/FiO(2) ratio<10 change with iNO) with responders (>or=10 change). RESULT: Non-responders (n=16) had a PaO(2)/F(iO2) of 83+/-48 (mean+/-s.d.) and decreased to 74+/-44 after iNO. PaO(2)/FiO(2) increased from 70+/-48 to 151+/-63 with iNO among responders (n=36). The MHb/SigmaNO ratio was low (0.024+/-0.012) among non-responders compared with responders (0.07+/-0.053, P<0.005). CONCLUSION: Inadequate oxygenation response to iNO is associated with lower MHb/SigmaNO, suggesting suboptimal delivery of iNO to the pulmonary vasculature.

Characteristics of pulmonary hypertension in preterm neonates.

OBJECTIVE: Characteristics of preterm infants who develop pulmonary hypertension (PHT) and their response to inhaled nitric oxide (iNO) are not well described. Our objective was to identify risk factors for PHT in infants <37 weeks gestational age (GA) and to evaluate their response to iNO. STUDY DESIGN: A retrospective chart review was conducted in infants <37 weeks GA born from July/2000 to October/2005 who had an echocardiographic diagnosis of PHT in the first 4 weeks of life. A comparison non-PHT group was generated matched for GA and birth date. Data on prenatal and postnatal characteristics, response to iNO and mortality were collected. RESULTS: Low Apgar scores, preterm premature rupture of membranes, oligohydramnios, pulmonary hypoplasia and sepsis were independently predictive of PHT. Mortality was significantly higher in the PHT group (26.2% versus 4.1%; P<0.0001) compared to the control group. Low birth weight, severe intraventricular hemorrhage and male sex were significantly associated with death in infants with PHT. Thirty-seven percent (23/61) of infants with PHT were treated with inhaled NO. Infants < 29-week GA had poor response to iNO and the response to iNO increased with GA (P<0.02). CONCLUSIONS: Low Apgar scores, oligohydramnios and pulmonary hypoplasia are associated with the development of PHT in premature infants. The percentage of infants responding to iNO increases with advancing GA.

White blood cell left shift in a neonate: a case of mistaken identity.

We present a full-term male infant who presented with tachypnea and an increased band count on his complete blood count (CBC) with an immature to total neutrophil (I:T) ratio of 0.6 raising suspicion of early onset sepsis. A blood culture was drawn and he was started on appropriate antibiotics. The patient's clinical condition rapidly improved; however, the white cell count 'left shift' persisted. When a detailed family history was obtained, it was discovered that the father, paternal uncle and the grandfather had been diagnosed with Pelger-Huet anomaly (PHA). As the urine, blood and CSF cultures were all negative in this now well-appearing infant, the left shift on the CBC was believed to be due to inheritance of the PHA. We present this case to emphasize that even in this age of sophisticated laboratory evaluation, a good clinical history, including family history, and clinical evaluation, are essential for accurate diagnosis.

Effects of salmeterol on secretion of phosphatidylcholine by alveolar type II cells.

Beta-adrenergic agents enhance secretion of phosphatidylcholine (PC) by adult and fetal type II cells. We have previously shown that terbutaline stimulates secretion of PC by fetal type II cells, but the response wanes after 30 minutes. We studied the effects of salmeterol, a highly selective, long-acting beta2-adrenergic agonist that does not cause receptor desensitization, on PC secretion by adult type II alveolar cells in primary culture. Release of lactate-dehydrogenase was < 4% and did not vary with the concentration of salmeterol. Salmeterol stimulated PC secretion in a concentration-dependent manner. The maximum effective-concentration tested was 50 nM and the EC50 was 11.40 +/- 1.14 nM. Propranolol inhibited the effect of salmeterol on release of PC, confirming that the effects of salmeterol are mediated by beta-receptors. OT50, the time for onset of action, was 32.0 +/- 1.6 minutes. RT50, the time to achieve 50% recovery from maximal stimulation was, 393.0 +/- 20.2 minutes. We conclude that salmeterol stimulates PC secretion by type II cells through activation of beta-adrenergic receptors and has a longer duration of action (>6 hours) compared to other beta2-agonists. Salmeterol may be a useful drug with which to study the role of receptor desensitization in the developmental changes in PC secretion.