[Progress in preserved ratio impaired spirometry]

Preserved ratio impaired spirometry (PRISm) refers to the mode of a decrease in forced expiratory volume in 1 second (FEV₁) while the FEV₁/forced vital capacity (FVC) remains constant. PRISm was prevalent in the study population, but it is underreported in the current research. The cohort studies in European-American have found that the PRISm has a higher risk of developing chronic obstructive pulmonary disease (COPD), cardiovascular-related deaths and all-causes death than the normal lung function. PRISm may be one of the pre-COPD population, so early detection and prevention are crucial. In this review, we summarized the recent advances in the research of PRISm with the aim to increase understanding of PRISm, and to provide comprehensive evaluation and management for PRISm population.

[Analysis of pathogens and clinical characteristics of bloodstream infection in neutropenic children with hematological malignancies from 2014 to 2018]

目的

探讨儿童血液病患者在中性粒细胞缺乏（粒缺）期发生血流感染时的病原学分布、耐药情况，为该类患者合理使用抗菌药物提供数据支持。

方法

回顾性分析2014年1月至2018年12月中国医学科学院血液病医院收治的儿童血液病患者粒缺期发生血流感染时的临床特征、病原菌分布和药物敏感性数据。

结果

427例儿童血液病患者在粒缺期共发生537次血流感染，30 d全因死亡率为3.7%。其中44.7%例次血流感染的临床特征仅表现为发热，其病原菌以肠杆菌科细菌为主。血流感染常伴口腔黏膜、呼吸道及消化道症状，比例分别为20.7%、20.5%和14.3%。伴不同症状的血流感染病原菌分布不同（χ²=40.561，P=0.001）。共分离出550株病原菌，位于前5位的细菌分别为草绿色链球菌（109株，19.8%）、大肠埃希菌（99株, 18.0%）、表皮葡萄球菌（75株，13.6%）、肺炎克雷伯菌（67株，12.2%）和金黄色葡萄球菌（32株，5.8%）。耐药方面，肠肝菌科细菌及铜绿假单胞菌对于哌拉西林/他唑巴坦、碳青霉烯类药物的耐药率<5%。金黄色葡萄球菌中耐甲氧西林金黄色葡萄球菌（MRSA）的比例为9.7%。

结论

儿童恶性血液病患者粒缺期发生血流感染病原菌革兰阳性球菌与阴性杆菌比例大致相同，提示经验性抗菌药物使用应具有广谱性，常见分离菌耐药性仍处于较低水平，常用的碳青霉烯类、糖肽类、酶抑制剂复合物类药物如哌拉西林/他唑巴坦等仍具有较好效果。

Series of new β-cyclodextrin-cored starlike carriers for gene delivery

The development of safe and effective β-cyclodextrin (β-CD)-cored cationic star gene carriers has attracted considerable attention. In this work, a series of star-shaped hemocompatible CD-PGPP, CD-PGAEPP, and CD-PGAPP vectors composed of β-CD cores and piperazine (PP)-, N-(aminoethyl)piperazine (AEPP)-, or N-(3-aminopropyl)-2-pyrrolidinone (APP)-functionalized poly(glycidyl methacrylate) arms were successfully proposed and compared for highly efficient gene delivery. Such star carriers possess plentiful secondary amine, tertiary amine, and nonionic hydroxyl groups. CD-PGPP, CD-PGAEPP, and CD-PGAPP were effective in condensing plasmid DNA into nanoparticles, whose sizes were 100-200 nm and positive ζ potentials were 25-40 mV at nitrogen/phosphate (N/P) ratios of 10 and above. CD-PGPP, CD-PGAEPP, and CD-PGAPP showed significantly lower cytotoxicity than control poly(ethylenimine) (PEI; ∼25 kDa). At most N/P ratios, CD-PGAPP exhibited better gene transfection performance than CD-PGPP and CD-PGAEPP particularly in HepG2 cells. More importantly, in comparison with PEI, all of the CD-PGPP, CD-PGAEPP, and CD-PGAPP vectors did not cause undesirable hemolysis.

Different types of degradable vectors from low-molecular-weight polycation-functionalized poly(aspartic acid) for efficient gene delivery

Poly(aspartic acid) (PAsp) has been employed as the potential backbone for the preparation of efficient gene carriers, due to its low cytotoxicity, good biodegradability and excellent biocompatibility. In this work, the degradable linear or star-shaped PBLA was first prepared via ring-opining polymerization of β-benzyl-L-aspartate N-carboxy anhydride (BLA-NCA) initiated by ethylenediamine (ED) or ED-functionalized cyclodextrin cores. Then, PBLA was functionalized via aminolysis reaction with low-molecular-weight poly(2-(dimethylamino)ethyl methacrylate) with one terminal primary amine group (PDMAEMA-NH2), followed by addition of excess ED or ethanolamine (EA) to complete the aminolysis process. The obtained different types of cationic PAsp-based vectors including linear or star PAsp-PDM-NH2 and PAsp-PDM-OH exhibited good condensation capability and degradability, benefiting gene delivery process. In comparison with gold standard polyethylenimine (PEI, ∼ 25 kDa), the cationic PAsp-based vectors, particularly star-shaped ones, exhibited much better transfection performances.

Relationships between biochemical and physiological changes induced by exercise in postmyocardial infarction patients

AIM

AIM of the study was to examine the relationships between biochemical and physiological changes induced by exercise in postmyocardial infarction patients (PMIP) during the early stages of cardiac rehabilitation.

METHODS

Forty-nine male non-blockade recent PMIP, aged 63.8 ± 4.7 years, performed a graded exercise test on a motorised treadmill until volitional cessation or reaching any of the American College of Sports Medicine criteria. Blood pressure and rate-pressure product (RPP) were recorded every three minutes. A 12-lead electrocardiogram was monitored continuously and heart rate (HR) was taken from this. Blood samples were obtained by two methods; those used for testing blood lactate (BL) were taken from an already warmed finger tip before and during exercise, and the others used for enzymatic analysis based on lactate dehydrogenase (LDH), lactate dehydrogenase isoenzyme 1 (LDH-1), creatine kinase (CK) and creatine kinase polypeptide sub-unit MB (CK-MB) were collected by venipuncture from the antecubital vein pre and immediate post exercise test.

RESULTS

Highly significant correlations existed between exercise-induced changes in HR, RPP, BL and ST segment level with increased enzymes activity in serum, and 73.1% to 90.1% of the variance in percentage increase of the enzyme activity could be predicted from the variance in percentage increase of HR during exercise. However, the mechanism of these relationships may differ.

CONCLUSION

Since the rise in serum enzymes during submaximal exercise is primarily attributed to changes in membrane permeability in fatigued muscle, these relationships provide useful guidance to health professionals obtaining biochemical information about muscle fatigue.