Dan Waisman

L-selectin expression on polymorphonuclear leukocytes and monocytes in premature infants: Reduced expression after dexamethasone treatment for bronchopulmonary dysplasia

We examined the effect of dexamethasone on the expression of the adhesion molecule L-selectin on circulating polymorphonuclear leukocytes (PMLs) and monocytes from premature infants with bronchopulmonary dysplasia (BPD). Nineteen infants who received dexamethasone (Dex group) and 28 who did not receive dexamethasone (no Dex group) were studied. L-selectin expression, measured as mean fluorescence intensity, was lower on circulating PMLs (5.7 +/- 0.6 vs 10.6 +/- 0.7, p < 0.001) and monocytes (7.9 +/- 0.9 vs 12.5 +/- 0.9, p < 0.02) isolated from those who had received dexamethasone. Because L-selectin is important for the recruitment of PMLs to inflammatory foci in the lungs, we speculate that one of the mechanisms by which dexamethasone reduces inflammation in BPD is by impairing the ability of leukocytes to migrate into the BPD lesions.

Dose-related effects of hyperoxia on the lung inflammatory response in septic rats.

ABSTRACT We evaluated the effects of hyperoxia on pulmonary inflammatory changes in sepsis induced by cecal ligation and puncture (CLP) in rats. Seven groups were studied: sham-operated rats breathing air for 20 or 48 h; CLP breathing air for 20 or 48 h; and CLP + 100% oxygen for 20 h, or 70% oxygen for 48 h, or 100% oxygen intermittently (6 h/d) for 48 h. Video microscopy was used to monitor lung macromolecular leak, microvascular flow velocity, and shear rates, and lung morphometry was used for leukocyte infiltration and solid tissue area. Cell counts, tumor necrosis factor &agr;, and nitrites were determined in peripheral blood and lung lavage fluid. Expression of adhesion molecules in blood leukocytes was evaluated by flow cytometry. Cecal ligation and puncture induced inflammation manifested in leukopenia, left shift, thrombocytopenia, increased expression of L selectin and CD11, increased serum and lavage fluid tumor necrosis factor &agr; and leukocytes, and increased lung tissue area, macromolecular leak, and sequestration of leukocytes. Inhalation of 100% oxygen for 20 h increased nitrites (P < 0.01) and decreased leukocyte count in lavage fluid (P < 0.05) and attenuated lung macromolecular leak and changes in solid tissue area (P < 0.01). Inhalation of 70% oxygen (48 h) attenuated expression of adhesion molecules (P < 0.001) but failed to attenuate markers of lung inflammation. In contrast, intermittent 100% oxygen exerted favorable effects on markers of inflammation, attenuated leukocyte expression of L selectin and CD11 (P < 0.01), decreased pulmonary sequestration of leukocytes (P < 0.001), and ameliorated changes in macromolecular leak (P < 0.01) and lung solid tissue area (P < 0.05). Our data support the beneficial effects of safe subtoxic regimens of normobaric hyperoxia on the systemic and pulmonary inflammatory response following CLP.

Paracetamol effectiveness, safety and blood level monitoring during patent ductus arteriosus closure: a case series

Abstract Paracetamol was reported to be effective for patent ductus arteriosus (PDA) closure. We present a case series of PDA closure by paracetamol in seven premature infants. During the treatment, paracetamol blood levels did not exceed the recommended levels for analgesia and hyperthermia in six tested infants. None of the patients demonstrated significant disturbances of liver function.

Effects of inhaled nitric oxide on lung injury after intestinal ischemia-reperfusion in rats.

Splanchnic ischemia/reperfusion (I/R) induces a systemic inflammatory response with acute lung injury. Impaired production of endothelial nitric oxide (NO) plays a key role in this process. We evaluated the effects of early treatment with inhaled NO (iNO) on lung microcirculatory inflammatory changes during splanchnic I/R. I/R was induced in rats by occlusion of the superior mesenteric artery (SMA; 40 min) and reperfusion (90 min). Four groups were studied: Control, anesthesia only; Sham, all surgical procedures without I/R, ventilated with air; Air, SMA I/R, ventilation with air; and NO, SMA I/R, ventilation with NO (20 ppm) starting 10 min before reperfusion. Intravital video microscopy was used to monitor pulmonary macromolecular flux and capillary flow velocity (CFV). Leukocyte infiltration was determined by morphometry. SMA I/R decreased mean arterial blood pressure, capillary CFV (P < 0.01), and shear rate (P < 0.01), and increased pulmonary macromolecular leak by 138% ± 8% (P < 0.001). iNO markedly attenuated the increase in macromolecular leak (P < 0.01), blunted the decrease in capillary CFV (P < 0.05) and shear rate (P < 0.05), and prevented the increase in leukocyte infiltration of the lungs after SMA I/R (P < 0.05). The direct, real-time, in vivo data suggest that early institution of low-dose iNO therapy effectively ameliorates the acute remote pulmonary inflammatory response after splanchnic I/R.

Subpleural microvascular flow velocities and shear rates in normal and septic mechanically ventilated rats.

ABSTRACT Changes in pulmonary microhemodynamics are important variables in a large variety of pathological processes. We used in vivo fluorescent videomicroscopy of the subpleural microvasculature in mechanically ventilated rats to directly monitor microvascular flow velocity (FV) and shear rate in pulmonary arterioles, capillaries, and venules in healthy rats and in septic rats 20 h after cecal ligation and puncture (CLP). Observations were made through a small thoracotomy after injection of fluorescent microspheres (D = 1 &mgr;m) into the systemic circulation. The FVs were calculated off-line by frame-by-frame measurements of the distance covered by individual microspheres per unit of time. In healthy rats, inspiratory FV were 1322 ± 142 &mgr;m/s in subpleural arterioles and 599 ± 25 &mgr;m/s in capillaries. The highest FV was found in venules (1552 ± 132 &mgr;m/s). The calculated shear rates were 547 ± 62/s in arterioles and 619 ± 19/s in capillaries. The highest shear rates were detected in venules (677 ± 59/s). No significant changes in FV and shear rates were observed throughout the 1-h observation period in any of the microvascular compartments. Pulmonary microvascular FV and shear rates found in sham-operated rats in the CLP experiments were not significantly different from values of healthy rats. The CLP caused a significant increase in leukocyte sequestration in the lungs and a mean of 27% to 34% decrease in FV in all sections of the pulmonary microvasculature (P < 0.001 in capillaries and P < 0.05 in venules). Also, CLP caused a 23% decrease in capillary shear rate that reached only borderline statistical significance (P < 0.06) and a significant 35% decrease in mean shear rate in venules (P < 0.05). Fluorescent videomicroscopy is offered as a stable and reproducible method for in vivo determinations of pulmonary microhemodynamics in clinically relevant models of sepsis.

Nanostructure of the aqueous form of lung surfactant of different species visualized by cryo-transmission electron microscopy.

Cryogenic temperature transmission electron microscopy (cryo‐TEM) makes it possible to study the nanostructure of a wide range of fluid phases with a high degree of preservation. Most studies based on scanning electron microscopy or TEM employ specimen preparation techniques that give extraordinary results for tissues, but alter the native structure of complex fluid substances such as lung surfactant. In this paper, we evaluated direct‐imaging cryo‐TEM as a method to study the morphology of the aqueous form of lung surfactant. We compared the morphology of samples obtained from different species, and cryo‐TEM data to data obtained by staining‐and‐drying. We demonstrate that cryo‐TEM preserves and images much better sample morphology and fine details of the surfactant structures. We show that cryo‐TEM, a method based on physical fixation, which avoids chemical changes and aggregate rearrangement, is a most useful tool to further our understanding of lung surfactant and its function.

Equi-affine Invariant Geometry for Shape Analysis

Traditional models of bendable surfaces are based on the exact or approximate invariance to deformations that do not tear or stretch the shape, leaving intact an intrinsic geometry associated with it. These geometries are typically defined using either the shortest path length (geodesic distance), or properties of heat diffusion (diffusion distance) on the surface. Both measures are implicitly derived from the metric induced by the ambient Euclidean space. In this paper, we depart from this restrictive assumption by observing that a different choice of the metric results in a richer set of geometric invariants. We apply equi-affine geometry for analyzing arbitrary shapes with positive Gaussian curvature. The potential of the proposed framework is explored in a range of applications such as shape matching and retrieval, symmetry detection, and computation of Voroni tessellation. We show that in some shape analysis tasks, equi-affine-invariant intrinsic geometries often outperform their Euclidean-based counterparts. We further explore the potential of this metric in facial anthropometry of newborns. We show that intrinsic properties of this homogeneous group are better captured using the equi-affine metric.

Zn/Ga−DFO iron–chelating complex attenuates the inflammatory process in a mouse model of asthma

Background Redox-active iron, a catalyst in the production of hydroxyl radicals via the Fenton reaction, is one of the key participants in ROS-induced tissue injury and general inflammation. According to our recent findings, an excess of tissue iron is involved in several airway-related pathologies such as nasal polyposis and asthma. Objective To examine the anti-inflammatory properties of a newly developed specific iron–chelating complex, Zn/Ga−DFO, in a mouse model of asthma. Materials and methods Asthma was induced in BALBc mice by ovalbumin, using aluminum hydroxide as an adjuvant. Mice were divided into four groups: (i) control, (ii) asthmatic and sham-treated, (iii) asthmatic treated with Zn/Ga−DFO [intra-peritoneally (i/p) and intra-nasally (i/n)], and (iv) asthmatic treated with Zn/Ga−DFO, i/n only. Lung histology and cytology were examined. Biochemical analysis of pulmonary levels of ferritin and iron-saturated ferritin was conducted. Results The amount of neutrophils and eosinophils in bronchoalveolar lavage fluid, goblet cell hyperplasia, mucus secretion, and peri-bronchial edema, showed markedly better values in both asthmatic-treated groups compared to the asthmatic non-treated group. The non-treated asthmatic group showed elevated ferritin levels, while in the two treated groups it returned to baseline levels. Interestingly, i/n-treatment demonstrated a more profound effect alone than in a combination with i/p injections. Conclusion In this mouse model of allergic asthma, Zn/Ga−DFO attenuated allergic airway inflammation. The beneficial effects of treatment were in accord with iron overload abatement in asthmatic lungs by Zn/Ga−DFO. The findings in both cellular and tissue levels supported the existence of a significant anti-inflammatory effect of Zn/Ga−DFO.

Prophylactic treatment of asthma by an ozone scavenger in a mouse model

Our hypothesis that inflammation in asthma involves production of ozone by white blood cells and that ozone could be an inflammatory mediator suggests that scavengers of reactive oxygen species (ROS), for example, electron-rich olefins, could serve for prophylactic treatment of asthma. Olefins could provide chemical protection against either exogenous or endogenous ozone and other ROS. BALB/c mice pretreated by inhalation of d-limonene before an ovalbumin challenge exhibited significant attenuation of the allergic asthma symptoms. Diminution of the inflammatory process was evident by reduced levels of aldehydes, reduced counts of neutrophils in the BAL fluid and by histological tests. A surprising systemic effect was observed by decreased levels of aldehydes in the spleen, suggesting that the examination of tissues and organs that are remote from the inflammation foci could provide valuable information on the distribution of the oxidative stress and may serve as guide for targeted treatment.

Does Haptoglobin Phenotype Influence Postnatal Morbidity in Preterm Neonates

BACKGROUND Haptoglobin (Hp) is an acute phase protein with antioxidant, bacteriostatic, and anti-inflammatory activities. Hp proteins associated with the three major phenotypes differ in their proinflammatory and anti-inflammatory action. Inflammation and oxidative stress are both involved in most pathophysiological processes in premature infants. The objective of this study was to determine whether Hp phenotype influences clinical manifestations and sepsis incidence in the premature infants. OBJECTIVE Infants born before 35 weeks gestational age were prospectively evaluated for Hp phenotype and clinical events, including sepsis, necrotizing enterocolitis, bronchopulmonary dysplasia, intraventricular hemorrhage, and retinopathy of prematurity. The participants were observed until discharge. METHODS A total of 122 preterm infants were enrolled in the study. Clinical events were not affected by the Hp phenotype. The expression of Hp protein was extremely low in the study population. More septic episodes were found in infants with a birth weight greater than 1,500 g, although, the difference was not statistically significant. RESULTS Extremely low expression of Hp may explain the lack of a correlation between Hp phenotype and sepsis in preterm infants. Further research involving a larger neonatal population is required to better understand the role of the Hp phenotype in morbidity of premature infants.