滴灌次数对冬小麦根系生长及时空分布的影响

以新冬18号为材料,利用双管分根管栽法,模拟田间试验研究了拔节期后不同滴灌次数W₁（6次）、W₂（7次）、W₃（9次）、W₄（11次）（每次内、外管分别滴30 mm）对0～100 cm土层含水量,0～100 cm土层初、次生根干重和长度、根系活性分布及产量的影响。结果表明,随滴灌次数及总滴灌量的增加,0～40 cm土层的含水量增加,并延缓该土层的初生根干重和根长的衰减、促进次生根干重和根长增长,增加孕穗期至花后20 d初、次生根干重密度、根长密度及根系活性,而对40～100 cm土层根系的生长影响较小。小麦产量和水分利用效率均以W₄最高,分别为25.5 g·管^-1和1.36 kg·m^-3 。当滴灌量少、湿润土层浅时,小麦深层初、次生根生长易受严重抑制,且根系分布浅,初生根提前衰老,导致千粒重降低而减产。     

头帽-J钩与微种植钉压低上颌切牙的疗效比较

目的比较头帽-J钩与微种植钉压低上颌切牙时的临床疗效。方法选择上颌前部牙槽骨发育过度的成年患者21例,分J钩组9例,种植组12例,分别使用头帽-J钩和微种植钉压低切牙,比较2组压入术前后头颅定位侧位片相关指标及矫治时间。结果 2组U1-PP均明显减少(P<0.01),种植组减少量大于头帽-J钩组(P<0.01);U1-Sv种植组增大(P<0.01),头帽-J钩组减少(P<0.01);U1/PP角种植组增大(P<0.01),头帽-J钩组变化不明显(P>0.05);U6-PP2组变化均无统计学差异(P>0.05);U6-Sv种植组增大(P<0.01),J钩组变化无统计学差异(P>0.05);压低时间种植组小于头帽-J钩组(P<0.01)。结论微种植螺钉和头帽-J钩均可以很好的压低切牙,微种植螺钉压入效果优于头帽-J钩,并用时少,但会引起切牙唇倾加重后牙支抗负担。     

Epidermal growth factor receptor in corneal damage: update and new insights from recent reports

Agonist and antagonist drugs acting on epidermal growth factor receptor (EGFR) signaling are emerging as a new possibility for pharmaceutical study and clinical manipulation of some skin and corneal disorders. EGFR activation appears to be effective in reducing the time of reepithelialization after corneal wound healing, with potential uses in penetrating keratoplasty, refractive surgery, alkali burns, diabetic keratopathy, keratopathy following chemotherapy, cornea transplantation, and dry eye. Most of the studies show therapeutic advantages of human recombinant epidermal growth factor (hrEGF) eye drops without showing adverse effects. In contrast, EGFR inhibition delays epithelial cell proliferation and stratification during corneal regeneration.The aim of this review is to summarize the most seminal discoveries and recent advances so as to clarify the role of the EGFR system in corneal physiology and pharmacology. Epidermal growth factor eye drops could be a first-choice treatment for promoting regeneration in numerous epithelial defects in the medium to long term.     

Nasal and pulmonary drug delivery systems

The respiratory route of administration has long been the medically desired drug delivery portal for the administration of topical anti-inflammatory drugs. These drugs are administered either to the lung, i.e., the lower respiratory system to treat asthma, or to the nasal cavity, i.e., the upper respiratory system to treat allergic rhinitis. This therapeutic focus dominates the drug delivery applications for the respiratory system. More recently, the respiratory system has provided a non-invasive method for the administration of biotherapeutics. And finally, formulation and device advancements have led to the consideration of the respiratory route for a number of other therapeutic applications where systemic delivery is desirable. All of these factors have resulted in the therapeutic patents that are discussed in this review.     

Gentamicin and leucine inhalable powder: What about antipseudomonal activity and permeation through cystic fibrosis mucus?

The aim of this study was to evaluate the permeation properties of gentamicin (G) in a novel dry powder form for inhalation through an artificial mucus model. Moreover, since respiratory infections sustained by Pseudomonas are a major cause of sickness and death in CF patients, the susceptibility of P. aeruginosa to engineered G powders was investigated.     

小分子糖负载血小板+冻干保护剂混合悬液的相变点测定与屏蔽实验研究

目的测定冻干血小板长期保存预冻程序和所依据的制品相变点温度并摸索相应屏蔽相变点的最佳冷冻曲线。方法研制出小分子糖负载血小板+冻干保护剂混合悬液,使用速率程序降温仪分析测定该混合悬液样品的相变点温度;根据测得的相变点温度,设计屏蔽相变点的预冻程序,根据温度变化曲线,判断相变点屏蔽结果。结论该混合悬液样品的相变点温度为(-13.56±2.05)℃;据此相变点温度所设计的3种相应的屏蔽相变点的预冻程序中,程序3为最佳冷冻曲线。结果获得了小分子糖负载血小板+冻干保护剂混合悬液的相变点温度及相应的屏蔽相变点的最佳预冻程序。     

A new respirable form of rifampicin

The aim of this research was to investigate a novel dry powder formulation of rifampicin (RF) that presents an improved lung deposition profile by means of a polymorphic transformation into a flake-like crystal hydrate. Rifampicin dihydrate (RFDH) was prepared by recrystallization of RF in anhydrous ethanol. A control formulation, amorphous RF (RFAM) was prepared by spray drying. The physicochemical properties of the RFDH and the RFAM were characterized. Aerosol performances of RFDH and RFAM were studied with two dry powder inhalers (DPIs), an Aerolizer® and a Handihaler®, using a Next Generation Impactor (NGI). The RFDH powder was successfully prepared using simple recrystallization process and had a MMAD of 2.2 μm. The RFDH powders were characterized as having a very thin flaky structure; this unique morphology provided improved aerosolization properties with a decreased device dependency upon aerosolization. The flaky morphology of RFDH resulted in a reduced agglomeration tendency than that of spherical RFAM particles. The maximum fine particle fraction (FPF_TD) of 68% for the RFDH was achieved with the Aerolizer® device. Significant chemical degradation was not observed from the RFDH, while the RFAM showed significant chemical degradation at 9 months. The excipient-free formulation of the RFDH offers the benefit of delivering a maximum potency formulation, of the antibiotic, directly to the site of infection, the lung.     

Stable dry powder inhaler formulation of tranilast attenuated antigen-evoked airway inflammation in rats

Tranilast (TL) has been clinically used for the treatment of airway inflammatory diseases, although the clinical use of TL is limited because of its poor solubility and systemic side effects. To overcome these drawbacks, a novel respirable powder of TL (CSD/TL-RP) for inhalation therapy was developed using nanocrystal solid dispersion of TL (CSD/TL). Stability study on CSD/TL-RP was carried out with a focus on inhalation performance. Even after 6 months of storage at room temperature, there were no significant morphological changes in micronized particles on the surface of carrier particles as compared with that before storage. Cascade impactor analyses on CSD/TL-RP demonstrated high inhalation performance with emitted dose and fine particle fraction (FPF) of ca. 98% and 60%, respectively. Long-term storage of CSD/TL-RP resulted in only a slight decrease in FPF value (ca. 54%). Inhaled CSD/TL-RP could attenuate antigen-induced inflammatory events in rats, as evidenced by marked reduction of granulocytes in bronchoalveolar lavage fluid and inflammatory biomarkers such as eosinophil peroxidase, myeloperoxidase, and lactate dehydrogenase. These findings were consistent with decreased expression levels of mRNAs for nuclear factor-kappa B and cyclooxygenase-2, typical inflammatory mediators. Given these findings, inhalable TL formulation might be an interesting alternative to oral therapy for the treatment of asthma and other airway inflammatory diseases with sufficient dispersing stability.