Medical gases

Understanding the complex process of production, storage and delivery of medical gases is vitally important to ensure safe and efficient practice by anaesthetists. This article discusses the medical gases commonly used in anaesthesia and intensive care and details the journey of the commonly used medical gases from production to patient delivery. It includes core knowledge for the FRCA.     

Carbon plate shows even distribution of stress,decreases screw loosening,and increases recovery of preoperative daily feed intake amount in a rabbit model of mandibular continuity defects

IntroductionThe aim of this study was to compare a carbon plate (CP) and a titanium mandibular reconstruction plate (TMRP) in finite element analysis and an animal model.Materials and methodsTwelve rabbits were used for this experiment. After a mandible continuity defect was created, either a CP or a TMRP was used for mandibular reconstruction. Postoperatively, daily feed intake amount (DFIA) was measured for 4 weeks. Radiographic images were also acquired to evaluate screw loosening. For the analysis of the stress distribution, a simple continuity defect model was used, and finite element analysis was performed.ResultsThe CP group had 0.80 ± 0.45 lost screws in an animal during the 4 weeks postoperative observation; however, the TMRP group had 1.86 ± 0.69 lost screws (p = 0.014). Overall, the 5 out of 5 of rabbits in the CP group and 3 out of 7 in the TMRP group exhibited preoperative levels of DFIA during the 4 week observation (p = 0.038). The finite element analysis showed that the stress was more evenly distributed in the CP than in the TMRP model.ConclusionsThe CP group showed decreased screw loosening and increased recovery of preoperative DFIA compared to the TMRP group in a rabbit model of mandibular continuity defects. Perfect adaptation of CP during the operation could not be achieved in spite of reshaping to the mandibular curvature. This disadvantage of the CP system can be overcome by the prefabricated technique using a prototype model.     

Interstitial lung diseases in children

Interstitial lung disease (ILD) in children (chILD) is a heterogeneous group of rare respiratory disorders that are mostly chronic and associated with high morbidity and mortality. The pathogenesis of the various chILD is complex and the diseases share common features of inflammatory and fibrotic changes of the lung parenchyma that impair gas exchanges. The etiologies of chILD are numerous. In this review, we chose to classify them as ILD related to exposure/environment insults, ILD related to systemic and immunological diseases, ILD related to primary lung parenchyma dysfunctions and ILD specific to infancy. A growing part of the etiologic spectrum of chILD is being attributed to molecular defects. Currently, the main genetic mutations associated with chILD are identified in the surfactant genes SFTPA1, SFTPA2, SFTPB, SFTPC, ABCA3 and NKX2-1. Other genetic contributors include mutations in MARS, CSF2RA and CSF2RB in pulmonary alveolar proteinosis, and mutations in TMEM173 and COPA in specific auto-inflammatory forms of chILD. However, only few genotype-phenotype correlations could be identified so far. Herein, information is provided about the clinical presentation and the diagnosis approach of chILD. Despite improvements in patient management, the therapeutic strategies are still relying mostly on corticosteroids although specific therapies are emerging. Larger longitudinal cohorts of patients are being gathered through ongoing international collaborations to improve disease knowledge and targeted therapies. Thus, it is expected that children with ILD will be able to reach the adulthood transition in a better condition.     

Nanotubes in the human respiratory tract – Deposition modeling

Deposition of inhaled single-wall carbon nanotubes (SWCNT) and multi-wall carbon nanotubes (MWCNT) in the respiratory tract was theoretically investigated for various age groups (infants, children, adolescents, and adults). Additionally, possible effects of the inhalative flow rate on nanotube deposition were simulated for adult lungs. Theoretical computations were based on the aerodynamic diameter concept and the assumption of particles being randomly transported through a stochastic (close-to-realistic) lung structure. Deposition of nanotubes was calculated by application of well validated empirical deposition formulae, thereby considering Browian motion, inertial impaction, interception, and sedimentation as main deposition mechanisms acting on the particles. Results of the simulations clearly show that for a given inhalation scenario (sitting breathing) total, bronchial, and acinar nanotube deposition increase with subject's age, whereas extrathoracic deposition is characterized by a decrease from younger to older subjects. According to the data provided by the model, MWCNT, whose aerodynamic diameters exceed those of SWCNT by one order of magnitude, are deposited in specific respiratory compartments to a lower extent than SWCNT. A change of the physical state from sitting to heavy work results in a common decline of bronchial and extrathoracic deposition of nanotubes. Total deposition is slightly increased for SWCNT and moderately decreased for MWCNT, whereas acinar deposition is significantly increased for SWCNT and decreased for MWCNT. Based on the results of this contribution it may be concluded that SWCNT bear a higher potential as health hazards than MWCNT, because they are accumulated in sensitive lung regions with higher doses than MWCNT.     

平阳霉素治疗跖疣的疗效观察

目的 评价平阳霉素治疗跖疣的临床疗效和安全性.方法 120例跖疣患者随机分为A组、B组和C组各40例,A组患者采用局部注射平阳霉素,每月1次,连续1～2次；B组患者采用CO2激光治疗,每月1次,连续1～2次；C组患者采用液氮冷冻,每月1次,连续1～2次.结果 A组患者治疗后基愈率为75.00％、显效率为17.50％、进步率为7.50％、无效率为0％,总有效率为92.50％；B组患者治疗后基愈率为52.50％、显效率为22.50％、进步率为17.50％、无效率为7.50％,总有效率为75.00％;C组患者治疗后基愈率为50.00％、显效率为22.50％、进步率为22.50％、无效率为5.00％,总有效率为72.50％.A组与B、C组疗效比较差异均有显著的统计学意义(Uc=5.3750,P=0.0204；Uc=6.4645,P=0.0110);B与C组疗效比较差异无显著的统计学意义(Uc=0.0355,P=0.8506).三组患者均无明显不良反应.结论 平阳霉素治疗跖疣是安全的、有效的.     

纳米石墨碳对人L-02细胞系生长状况的影响

目的研究纳米石墨碳对人正常肝细胞系L-02生长状况的影响。方法电子显微镜观察纳米石墨碳颗粒的形态,激光粒度分析仪测定其粒径及Zeta电位;流式细胞术检测纳米石墨碳作用24 h对L-02肝细胞生长周期的影响;电镜观察细胞剖面,用以考察纳米石墨碳颗粒对L-02肝细胞亚显微结构的影响。结果电镜下纳米石墨碳颗粒呈微小球形,粒径在20～50 nm,表面带负电荷,电位值为-14.8 mV;流式细胞检测结果示实验组L-02肝细胞G0/G1细胞百分数低于对照组,G2/M细胞百分数高于对照组,S期细胞百分数高于对照组;电镜观察纳米石墨碳在细胞质和细胞核内均有分布,实验组肝细胞内的线粒体与对照组无明显差异,胞膜核膜均完整。结论纳米石墨碳颗粒促进了L-02肝细胞的增殖,纳米石墨碳颗粒可以很好地进入到L-02肝细胞内部,未见其对细胞亚显微结构造成损伤。     

Life-threatening pulmonary embolism that occurred immediately after acute carbon monoxide poisoning in the emergency department

The risk of thromboembolism is higher in those with carbon monoxide (CO) poisoning than in the general population. Pulmonary embolisms (PE) usually develop during admission for acute CO poisoning. We report the first case of a life-threatening PE that occurred immediately after acute CO poisoning and was treated with a thrombolytic agent. A 38-year-old woman presented at the emergency department with a stuporous mental status immediately after acute CO poisoning. She was started on hyperbaric oxygen therapy (HBOT), which maintained her hemodynamic stability. After completing the first HBOT session, profound shock occurred. The results of focused cardiac ultrasound performed by an emergency physician were completely different from those of the ultrasound conducted before HBOT; hyperdynamic left ventricle systolic function and right ventricle enlargement with dysfunction were detected. We administered a thrombolytic agent as she was suspected with acute PE based on ultrasound findings; computed tomography could not be performed because of impending arrest. She recovered after the treatment. We should consider that PE is also an important differential cause in patients with hypotension. In these patients, bedside ultrasound performed by emergency physicians can act as the only diagnostic examination.     

Expression of muscarinic acetylcholine receptors in hepatocytes from rat fibrotic liver

The pathological changes of parasympathetic nerve are considered as an independent prognostic factor of the survival rate of patients with chronic liver disease. The non-selective muscarinic acetylcholine receptors (mAchR) agonists and antagonists can affect the proliferation of hepatocytes and hepatic stellate cells, but the subtypes of mAchR expressions in HCs are still uncertain. Here, we investigate the expression of mAchR in hepatic fibrosis on rats. 3 ml/kg 40% carbon tetrachloride (CCL4) was given to induce hepatic fibrosis on rats and the hepatocytes were isolated. Compared to the normal state, the expression levels of m1, 3, 5 in fibrotic liver tissues or hepatocytes were obviously increased, while m2, 4 decreased. 10 μM pilocarpine or 10 μM acetylcholine could increase the alanine aminotransferase (ALT), hydroxyproline (Hyp), collagen I, III in the hepatocytes, and decreased albumin (ALB). They also changed the expressions of mAchR similarly as the fibrotic hepatocytes and livers. However, atropine could ameliorate the state of fibrotic hepatocytes. These data indicate that mAchR played an important role in the regulation of hepatic fibrosis process. Targeting mAchR would have therapeutic potential for hepatic fibrosis.     

Effect of BSA on carbon nanotube dispersion for in vivo and in vitro studies

Carbon nanotubes (CNT) are one of the most promising nanomaterials because of their intrinsic properties. So, it becomes urgent to assess their toxicity. However, CNT are insoluble in aqueous media required for toxicological studies. Thus, we propose a simple method to disperse CNT for toxicological studies using a biomolecule: The albumin. To evaluate this method, several nanotubes were suspended in saline solution (NaCl 0.9%) without or with albumin at a concentration of 0.5 mg/ml or equal as CNT concentration. These suspensions were visually compared to suspensions obtained with classical dispersing methods using Tween 80 or serum. Homogeneity of the suspensions with or without BSA and CNT structure were analyzed by TEM, agglomerates quantification and total carbon dosage. The effect of coupled albumin-CNT was then tested on A549 and U937 cells in vitro and on rats in vivo. Total carbon dosage, agglomerates quantification and TEM revealed that, in the presence of albumin, the tested nanotubes were better dispersed without any modification of their structure. The CNT suspension was tested in vitro and in vivo in rats. Albumin solution alone induced no modification of the biological responses studied (i.e., cell viability in vitro and inflammatory response and histopathology in vivo) compared to the saline. CNT in NaCl or BSA altered cellular viability in vitro in a similar way but results obtained with CNT suspension in the presence of albumin showed a better reproducibility that can be explained by the better homogeneity of the suspensions. CNT in BSA but not in NaCl significantly increased the cell number in BAL and also the number of apparent CNT-containing cells. Taken together, these results highlight the potential importance of CNT dispersion (and thus of the vehicle) for the toxicological studies.