家庭雾化吸入治疗反复喘息患儿疗效观察

目的探讨家庭雾化吸入治疗反复喘息患儿的疗效。方法前瞻性分析2012-2013年住院治疗的反复喘息患儿316例,按照是否进行家庭雾化规范治疗分为家庭雾化吸入组和非家庭雾化吸入组。观察家庭雾化吸入治疗反复喘息患儿,能否降低再次住院率、应用全身糖皮质激素及抗生素使用率。结果家庭雾化吸入组198例,随访1年当中其再次住院率为20.2%,门急诊就诊率为66.6%,应用全身糖皮质激素16.6%,应用抗生素65.6%,有症状天数14±5.2天,明显低于非家庭雾化吸入组,差异有统计学意义(P0.05),而两组间一年的医疗费用无统计学差异(P0.05)。结论家庭雾化吸入治疗,可降低反复喘息患儿再次住院率、门急诊就诊率、有症状天数及应用全身糖皮质激素、抗生素治疗次数而一年的医疗费用无增加。     

Modulation of α1β3γ2 GABAA receptors expressed in X. laevis oocytes using a propofol photoswitch tethered to the transmembrane helix

Tethered photoswitches are molecules with two photo-dependent isomeric forms, each with different actions on their biological targets. They include reactive chemical groups capable of covalently binding to their target. Our aim was to develop a β-subunit-tethered propofol photoswitch (MAP20), as a tool to better study the mechanism of anesthesia through the GABA_A α1β3γ2 receptor. We used short spacers between the tether (methanethiosulfonate), the photosensitive moiety (azobenzene), and the ligand (propofol), to allow a precise tethering adjacent to the putative propofol binding site at the β⁺α⁻ interface of the receptor transmembrane helices (TMs). First, we used molecular modeling to identify possible tethering sites in β3TM3 and α1TM1, and then introduced cysteines in the candidate positions. Two mutant subunits [β3(M283C) and α1(V227C)] showed photomodulation of GABA responses after incubation with MAP20 and illumination with lights at specific wavelengths. The α1β3(M283C)γ2 receptor showed the greatest photomodulation, which decreased as GABA concentration increased. The location of the mutations that produced photomodulation confirmed that the propofol binding site is located in the β⁺α⁻ interface close to the extracellular side of the transmembrane helices. Tethering the photoswitch to cysteines introduced in the positions homologous to β3M283 in two other subunits (α1W288 and γ2L298) also produced photomodulation, which was not entirely reversible, probably reflecting the different nature of each interface. The results are in agreement with a binding site in the β⁺α⁻ interface for the anesthetic propofol.

While photoswitches have been a popular topic in numerous reviews (1), their application in research is still very rare. Photoswitches are freely diffusible molecules containing a photosensitive moiety which can alternate between two isomeric forms depending on light irradiation at specific wavelengths. These isomeric forms of the photoswitch possess different affinities or efficacies toward their biological target, such that their pharmacological activity can be turned on or off depending on the light wavelength used, thus providing temporal and spatial control. When photoswitches covalently tether to a native or engineered residue at the specific biological target, the resulting conformation would determine the corresponding pharmacological activity. One way the tethered photoswitch can be activated is by positioning the tether in such a way that the ligand moiety can reach its binding site in only one of the photoswitch conformations. Additional major advantages of the tethered photoswitches are high local concentration (the residue cannot diffuse away) and spatial restriction within the biological target. The ligand groups of photoswitches can possess diverse pharmacological activities, acting as agonists, inverse agonists, or antagonists at specific binding sites.The GABA_A receptor is formed by five subunits (usually two α, two β, and one γ or δ) arranged in pseudosymmetry around a central channel, in the following order (counterclockwise, viewed from the extracellular side): γ-β-α-β-α (2). Each interface is named after the subunits that form it, with “+” and “−” designated following the counterclockwise order (a model of the α1β3γ2 GABA_A receptor can be found in SI Appendix, Fig. S1). Each subunit consists of an extracellular domain, attached to a sequence of four transmembrane helices (TMs), with a large intracellular loop inserted between TM3 and TM4. Multiple anesthetic drugs that act through this receptor possess relatively low binding affinities; therefore, precise identification and characterization of their binding sites require the use of techniques like mutagenesis, substituted cysteine modification protection (SCAMP), and photolabeling with photoreactive anesthetic analogs (3). Structures of the GABA_A receptor with bound anesthetic drugs have recently been made available (4), but one unexplored way of obtaining valuable, functional information would be by using appropriately designed tethered photoswitches. In previous studies of GABA_A receptors, the photoswitches used have included diffusible propofol photoswitches (5, 6) and a tethered propofol photoswitch with a very long spacer between the tethering cysteine (located in the extracellular domain) and the propofol moiety (6). Though all three positively modulated GABA_A receptors, none could be used to define the propofol binding site.Multiple studies point to propofol binding cavities being located in the TM interfaces between GABA_A receptor subunits. The observation that specific mutations in TM2 or TM3 of GABA_A β subunits could dramatically decrease propofol potentiation of GABA responses, and even direct activation of the receptor (7–9) led to the development of the β3(N265M) knockin mouse, which showed either a greatly decreased or absent hypnotic effect of propofol, depending on the test used (10). More recent studies have focused on a more complete characterization of binding sites for propofol as well as other intravenous anesthetics. A photoreactive propofol analog labeled three amino acids in the β⁺α⁻ interface (β3M286, α1M236, and α1I239) and one in the α⁺β⁻ interface (β3M227) in α1β3 receptors. Using etomidate and R-mTFD-MPAB [R-5-allyl-1-methyl-5-(m-trifluoromethyldiazirinylphenyl)barbituric acid] to inhibit photolabeling established that propofol also binds to the β⁺β⁻ interface, suggesting that propofol shows little selectivity for either interface (11). Another study mutated photolabeled residues (α1M236, β3M227, and their homologs, all located in TM1) to tryptophan (causing steric occupancy of the pocket) and cysteine (to test propofol protection against cysteine-specific labeling) (12). SCAMP studies confirmed that propofol binds to the β⁺α⁻ and α⁺β⁻ interfaces, and also to the γ⁺β⁻ interface; there was no evidence of binding to the α⁺γ⁻ interface. A more recent study has expanded the analysis of residues at the β⁺α⁻ interface that line a putative propofol binding site (13) (SI Appendix, Fig. S1). And cryoelectron microscopy (cryo-EM) structures of α1β2γ2 GABA_A receptors bound to intravenous anesthetics and benzodiazepines have recently been published (4), consolidating the evidence toward a propofol binding site at the β⁺α⁻ interfaces.Our aim was to develop a β-subunit-tethered propofol photoswitch, as a tool to better study the mechanism of anesthesia through the GABA_A α1β3ɣ2 receptor, merging both structural and functional approaches. This tethered photoswitch (Fig. 1A) consists of propofol as the ligand group, linked to an azobenzene group (which is photosensitive and can change between cis and trans isomeric forms, Fig. 1B), and finally a tethering group (methanethiosulfonate, that spontaneously forms a covalent bond with the thiolate group of cysteines located in water-filled cavities). This photoswitch was abbreviated as MAP20 (methanethiosulfonate azobenzene propofol 2020). These three basic components of this tethered photoswitch are connected by short spacers, decreasing the range between tethering and target residues. We used β3 subunits in our study because the immobilizing and hypnotic effects of propofol are mostly mediated by β3-containing receptors (10).Open in a separate windowFig. 1.Tethered photoswitch. (A) Methanethiosulfonate azobenzene propofol 2020 (MAP20) consists of propofol (ligand group), an azobenzene moiety (photosensitive), and a tether (methanethiosulfonate). (B) The azobenzene moiety can change between cis and trans isomeric forms depending on the wavelength of the light irradiated.     

Reflux-related symptoms reflect poor asthma control and the presence of airway neuronal dysfunction

BackgroundGastroesophageal reflux may be associated with the worsening of asthma by increasing cough reflex sensitivity. Hull Airway Reflux Questionnaire (HARQ) consists of 14 prevalent reflux-related symptoms. It may be useful in predicting the presence of cough reflex hypersensitivity in asthma.MethodsFrom August 2018 to July 2020, 266 asthmatic patients completed the HARQ. They underwent blood analysis, spirometry, fraction of exhaled nitric oxide (FeNO) measurement, and the capsaicin cough challenge test. Patients were considered to have reflux-related symptoms if their HARQ scores were 13 points or higher. We evaluated the association between reflux-related symptoms and clinical asthma outcomes. Finally, we performed a multivariate analysis to determine the clinical significance of the HARQ for asthma. This study was registered in the University Hospital Medical Information Network (UMIN000040732).ResultsThe mean HARQ scores were 13.1 (standard deviation 12.0). Patients in the high HARQ scores group (HARQ ≥13, n = 105) showed a lower prevalence of atopic predisposition, lower levels of FeNO, heightened capsaicin cough reflex sensitivity, poorer asthma control, and more frequent admissions due to asthma than those in the low HARQ groups (all p values < 0.05). The HARQ was useful in selecting patients with poor controlled asthma and those with severe cough when the cut-off value was set at 13. Multivariate analysis revealed that heightened capsaicin cough reflex sensitivity affected reflux-related symptoms, as well as lower levels of FeNO and younger age.ConclusionsHigher HARQ scores (≥13) may be useful in predicting not only poor asthma condition but also the presence of airway neuronal dysfunction in patients with asthma to some extent.     

The potential value of a 750-ml spacer for the administration of inhaled corticosteroids to children

An open, cross-over trial was conducted on 25 asthmatic children, aged 6-13 years, who required inhaled steroids. They inhaled Budesonide 200 micrograms twice daily, either directly from the metered dose inhaler or via the pear spacer (PS), for 2 months on each, in randomized order. The effects of the treatment were monitored with diary cards recording peak expiratory flow rates twice daily, symptoms and treatment taken, and with monthly clinical assessments including more sensitive lung function studies (flow-volume loops and single breath nitrogen wash-out tests). There was no specifically PS-related improvement in symptoms or in the majority of tests, but the results showed improvement with time when using either method. The improvement was more distinct in some tests reflecting proximal airway calibre (i.e., PEFR) than in tests thought to reflect predominantly peripheral airway calibre (i.e., F50, RV). The bronchodilator responsiveness, as shown by the increase in lung function tests after a beta-agonist was given, was significantly greater for FVC during the periods when the PS was used, although there was no significant improvement in FEV2 or PEFR. The improvement in tests reflecting proximal airways may have been due to optimization of the inhalation technique, greater understanding of asthma, or better compliance with medication associated with regular attendance for the study. The greater bronchodilator response whilst children were inhaling budesonide by the PS may have been due to increased deposition or better distribution of the steroid but was probably related to a difference between the two groups in initial baseline function tests.     

Pulmonary function over 2 years in diabetic patients treated with prandial inhaled Technosphere Insulin or usual antidiabetes treatment: a randomized trial

Aims: Development of inhaled insulin has increased the need to understand its pulmonary safety. This study evaluated pulmonary function changes in diabetes patients receiving inhaled Technosphere Insulin (TI) or usual antidiabetes treatment (usual care). Methods: This randomized, open‐label study was conducted at 220 sites (25 July 2005 to 29 August 2008). Pulmonary function tests [forced expiratory volume in 1 s (FEV₁), forced vital capacity (FVC), total lung capacity (TLC) and lung diffusion capacity for carbon monoxide (DL_CO)] were prospectively followed over 2 years in patients with type 1 or type 2 diabetes receiving TI (n = 730) or usual care (n = 824), along with a cohort without diabetes not receiving any specific therapy (n = 145). Results: Baseline demographics and pulmonary function were similar between diabetes treatment groups. Lung function declined from baseline in all groups. TI was non‐inferior to usual care for mean change in FEV₁ from baseline to month 24 [mean (s.e.m.) 0.037 (0.0119) l; 95% CI 0.014 to 0.060] using mixed‐model repeated‐measure with a pre‐specified non‐inferiority margin of 50 ml/year. After a greater initial decline at month 3 with TI, rate of change (slope) in FEV₁, FVC and DL_CO (months 3–24) was not statistically different between treatment groups. TI was well tolerated; no serious safety concerns emerged. The most common respiratory event associated with TI was mild, transient cough, occurring within minutes of inhalation. Conclusions: Observed changes in lung function with TI were small, occurred early after therapy initiation, remained non‐progressive over 2 years and were unlikely to be clinically meaningful.     

Asthma management and inhalation techniques among community pharmacists in 2009: a comparison with the 1999 survey

Objective: In a 1999 survey, community pharmacists from the Alsace region of France had a reasonably good knowledge of asthma treatment and prevention, but their skill in the use of asthma inhalation devices left room for improvement. Since then, health authorities have encouraged the involvement of community pharmacists in patient care and education in order to improve asthma control. The aim of this study was to assess the change in the knowledge of asthma management and inhaler technique skills of community pharmacists in the same geographic area after a 10-year interval. Methods: In 2009, 86 randomly selected community pharmacists from the Alsace region answered a standardized questionnaire about their theoretical knowledge of and practical attitude toward asthma management and inhaled delivery systems, following which their skills in the use of four inhalation devices (pressurized metered-dose inhaler (pMDI) with/without a spacer, breath-actuated pMDI and dry powder inhaler (DPI)) were evaluated. Results: Very few pharmacists were required to manage an acute asthma exacerbation at the pharmacy, but all responded well by administering a short-acting inhaled β2-agonist. Theoretical knowledge of asthma management (criteria of severity of asthma exacerbation, guidelines and drugs triggering asthma exacerbations) was still average. Compared with 1999, they were twice as confident in demonstrating inhaler use, and their skills in using the pMDI, breath-actuated pMDI and DPI had improved significantly (p?Conclusions: Since 1999, pharmacists’ skill in the use of inhalers has improved, but theoretical knowledge of asthma management is still average, pointing to the importance of continuing pharmaceutical education.