Role of bilevel positive airway pressure in the management of preterm newborns who have received surfactant

Aim: Surfactant given during brief intubation followed by immediate extubation on nasal continuous positive airway pressure [Intubation‐Surfactant‐Extubation (InSurE) approach] is used to treat respiratory distress syndrome in newborns. Our aim was to evaluate whether bilevel positive airway pressure (BiPAP) after InSurE failure is able to prevent the need for mechanical ventilation (MV). Methods: Chart data of infants with a birth weight <1500 gr or GA <32 weeks undergoing InSurE in the period 2002–2008 in an Italian Tertiary Neonatal Intensive Care Unit were reviewed retrospectively. InSurE failure was defined as follows: FiO₂ >0.4, respiratory acidosis or intractable apnoea within 1 week. After InSurE failure, newborns born before the implementation of BiPAP (historical control group) received MV, whereas those born after BiPAP implementation (BiPAP group) received BiPAP and underwent MV only if failure criteria persisted. The two groups were compared to evaluate whether BiPAP reduced the need for MV in the 7 days after InSurE failure. Results: Six of twenty‐two (27%) and 14 of the 38 (37%) infants failed InSurE in the two groups, respectively (p > 0.05). Need for MV was 27% in the historical control group versus 0% in the BiPAP group (risk estimate, 3.38; 95% CI, 2.24, 5.09; p = 0.001). Conclusions: BiPAP reduced the need for MV after InSurE failure.     

Determination of the venous output function from MR signal phase: Feasibility for quantitative DCE‐MRI in human brain

For dynamic contrast‐enhanced MRI studies in the human brain, it is useful to measure the venous output function (VOF). The purpose of this work was to explore the feasibility of measuring the VOF using the MR signal phase (in absolute units of gadolinium concentration) in the superior sagittal sinus. Phantom experiments were performed to validate the technique for different superior sagittal sinus angles (θ = 0–48° relative to the main magnetic field), different curvatures (straight or radius = 45 mm), and different spatial resolutions (2.2–5.5 mm, to study partial‐volume effects). Additionally, the technique was tested on three patients. The phantom experimental results (echo time = 5.5 ms, θ ≤ 21°) agreed with theoretical predictions to within 10%. For the patient studies, the measured VOFs had reasonable amplitude and shape characteristics and the patients' superior sagittal sinus angles (<15°) and curvatures (radii ≈ 40 mm) were within the range explored with phantoms. Our results suggest that partial‐volume contributions to the VOF will be <5% and that the VOF can be evaluated in vivo to within 10% error. In conclusion, it is highly feasible to use MR signal phase to measure the VOF in the superior sagittal sinus for human dynamic contrast‐enhanced MRI. Magn Reson Med 63:772–781, 2010. © 2010 Wiley‐Liss, Inc.     

2型糖尿病患者肾动态显像的研究

目的通过肾动态显像探讨不同阶段2型糖尿病(DM)患者肾脏血流动力学的变化及肾功能受损情况。方法 69例2型DM患者根据尿白蛋白排泄率(UAER)分为DM1组、DM2组、DM3组,进行SPECT肾动态显像观察,并与30例正常对照(Nc)组比较。结果 DM1组肾小球滤过率(GFR)及肾有效血浆流量(ERPF)明显高于Nc组。DM2组GFR、ERPF与Nc组相比无显著性差异,但其肾功能曲线半排时间(t1/2)延长,20 m in残留率(C20)增高。DM3组GFR、ERPF明显下降,肾功能曲线峰时(tp)后延,t1/2明显延缓,C20显著增高。结论核素肾动态显像可早期了解2型DM各时相肾脏血流动力学的变化及肾功能受损程度,为临床DM治疗和随访提供可靠依据。     

Pilot study of oxygen transport rate of banked red blood cells

Background and Objectives  Dynamic oximetry provides a new way to assess the effect of blood storage on the oxygen transport rate (OTR).
Materials and Methods  In dynamic oximetry, the rate at which oxyhemoglobin becomes deoxyhemoglobin is measured optically, thereby, indirectly measuring the rate at which oxygen leaves the red blood cell (RBC) making it available for transfer to tissues. Extending the physiologic diffusion time in an in vitro apparatus, consisting of a diffusion system and gas exchanger capable of controlling the surface area and the time of exposure for oxygenation and deoxygenation, makes OTR measurement feasible. Eight normal blood donor units, collected in adenine, dextrose, sorbitol, sodium chloride and mannitol , were stored for 8 weeks under standard conditions and serially sampled for OTR.
Results  We report that the OTR at the time of blood bank donation appears to be singular for each donor, that the interdonor differences are maintained over time, and that the individual OTR increased 1·72-fold (95% CI 1·51, 1·95) over 8 weeks, adjusting for sex, age and plasma cholesterol level.
Conclusion  Oxygen transport rate increases during storage; blood units with similar haemoglobin content may have significant differences in OTR. Studies examining blood parameters at the time of donation and blood storage on patient outcomes should consider measuring OTR, as it may contribute to differences in observed efficacy of tissue oxygenation.     

Microtubule plus-end tracking by CLIP-170 requires EB1

Microtubules are polarized polymers that exhibit dynamic instability, with alternating phases of elongation and shortening, particularly at the more dynamic plus-end. Microtubule plus-end tracking proteins (+TIPs) localize to and track with growing microtubule plus-ends in the cell. +TIPs regulate microtubule dynamics and mediate interactions with other cellular components. The molecular mechanisms responsible for the +TIP tracking activity are not well understood, however. We reconstituted the +TIP tracking of mammalian proteins EB1 and CLIP-170 in vitro at single-molecule resolution using time-lapse total internal reflection fluorescence microscopy. We found that EB1 is capable of dynamically tracking growing microtubule plus-ends. Our single-molecule studies demonstrate that EB1 exchanges rapidly at microtubule plus-ends with a dwell time of <1 s, indicating that single EB1 molecules go through multiple rounds of binding and dissociation during microtubule polymerization. CLIP-170 exhibits lattice diffusion and fails to selectively track microtubule ends in the absence of EB1; the addition of EB1 is both necessary and sufficient to mediate plus-end tracking by CLIP-170. Single-molecule analysis of the CLIP-170–EB1 complex also indicates a short dwell time at growing plus-ends, an observation inconsistent with the copolymerization of this complex with tubulin for plus-end-specific localization. GTP hydrolysis is required for +TIP tracking, because end-specificity is lost when tubulin is polymerized in the presence of guanosine 5′-[α,β-methylene]triphosphate (GMPCPP). Together, our data provide insight into the mechanisms driving plus-end tracking by mammalian +TIPs and suggest that EB1 specifically recognizes the distinct lattice structure at the growing microtubule end.     

Cyrene™ as an Alternative Sustainable Solvent for the Preparation of Poly(lactic-co-glycolic acid) Nanoparticles

Toxic and environmental harmful organic solvents are widely applied to prepare poly(lactic-co-glycolic acid) (PLGA)-based nanoparticles (NP) in standard preparation methods. Alternative non-toxic solvents suffer from disadvantages like high viscosity and plasticizing effects. To overcome these hurdles, Cyrene? as a new sustainable, non-toxic and low viscous solvent was used to formulate PLGA NPs. A new preparation method was developed and optimized. Small sized blank NPs around 220 nm with a narrow size distribution and highly negative charge (<?23 mV) were obtained. To test the application for drug delivery, the lipophilic model drug atorvastatin was encapsulated in high drug loads with comparable physicochemical characteristics as the blank NPs, and a total drug release within 24 h. No changes of the crystallinity or plasticizing effects could be observed. Highly purified NPs were obtained with a residual Cyrene? content <2.5%. Finally, the biocompatibility of Cyrene? itself and of the NPs formed in the presence of Cyrene? was demonstrated in a hen's egg test. Conclusively, the use of Cyrene? as solvent offers a simple, fast and non-toxic procedure for preparation of PLGA NPs as drug delivery systems circumventing the downsides of standard methods.     

Immunological characteristics and management considerations in obese patients with asthma

Obesity is associated with severe, poorly controlled asthma that does not respond as well to therapy as asthma in leaner asthmatics. Important insights gained from animal models of obesity and asthma suggests that different forms of obesity may lead to different manifestations of airway disease: obesity is associated with both innate increased airway reactivity and altered responses to aeroallergen and pollutant challenges. In humans, at least two broad groups of obese asthmatics have been recognized: one that is likely unique to obesity and another that is likely lean allergic asthma much complicated by obesity. This article will discuss what we have learned about the immunological and pathophysiological basis of asthma in obesity from animal and human studies, and how this might guide therapy.     

经鼻持续呼吸道正压通气、利多卡因雾化救治百日咳综合征憋气患者疗效观察

目的探讨经鼻持续呼吸道正压通气(NCPAP)、利多卡因雾化救治百日咳综合征憋气的疗效。方法选择伴有憋气的百日咳综合征患儿53例,随机分为两组,对照组27例予常规治疗和鼻导管给氧,观察组26例在常规治疗基础上配合NCPAP及利多卡因雾化吸入治疗。结果观察组在憋气Apgar评分改善1个级别天数、憋气消失天数、痉咳消失天数、喷嚏危象出现率、肺部并发症出现率等指标明显优于对照组,差异有统计学意义。结论经鼻持续呼吸道正压通气、利多卡因雾化在百日咳综合征憋气的急救中,可迅速控制病情,防止恶化,缩短病程。     

Percutaneous tracheostomy and cricothyrotomy techniques

Percutaneous tracheostomy is currently accepted as a standard technique for longer-term airway care in the critically ill patients in many intensive care units (ICUs). Early tracheostomy has not shown any survival benefit compared to late tracheostomy following prolonged tracheal intubation in ICU patients. The main indications for tracheostomy in the ICU setting include weaning from artificial ventilation or airway protection. Nevertheless, many questions about choice of techniques, post-tracheostomy care and decannulation remain unanswered. This review gives an overview of current techniques.