Protection of rats against perfluoroisobutene (PFIB)-induced pulmonary edema by curosurf and N-acetylcysteine

Airborne exposure to lung-toxic agents may damage the lung surfactant system and epithelial and endothelial cells, resulting in a life-threatening pulmonary edema that is known to be refractory to treatment. The aim of this study was to investigate in rats (1) the respiratory injury caused by nose-only exposure to perfluoroisobutene (PFIB), and (2) the therapeutic efficacy of a treatment at 4 and/or 8 h after exposure consisting of the natural surfactant Curosurf and/or the anti-inflammatory drug N-acetylcysteine (NAC). For that purpose, the following parameters were examined: respiratory frequency (RF), lung compliance (Cdyn), airway resistance (Raw), lung wet weight (LWW), airway histopathology; and in brochoalveolar lavage (BAL) fluid, total protein, total phospholipid, cell count and differentiation, and changes in the surface tension of the BAL fluid. The mean (+/- SEM) surface tension of BAL fluid derived from PFIB-exposed (C . t = 1100-1200 mg min(-1) m(-3), approximately 1LCt50; t = 20 min) animals at 24 h following exposure (11 +/- 3 mN/m) was higher than that of unexposed rats (0.8 +/- 0.4 mN/m), reflecting damage to the surfactant system and justifying treatment with exogenous surfactant. Curosurf treatment (62.5 mg/kg i.t.) decreased pulmonary edema caused by PFIB, reflected by a decreased LWW, and decreased the amount of protein in BAL fluid. NAC treatment (1000 mmol/kg ip) inhibited the interstitial pneumonia reflected by a decreased percentage of neutrophils in the alveolar space. It was concluded that a combined treatment of Curosurf + NAC improved respiration, that is, RF and Cdyn, whereby Curosurf predominantly decreased pulmonary edema and NAC predominantly reduced the inflammatory process. A combined treatment may therefore be considered a promising therapeutic approach in early-stage acute respiratory distress caused by PFIB, although the treatment regimes need further investigation.     

N-Acetylcysteine (NAC)-Induced Hyponatremia Caused by an Electronic Medical Record (EMR) Order Error

Introduction

Intravenous N-acetylcysteine (NAC) causes few adverse drug events, with mild anaphylactoid reactions being the most common. Hyponatremia as a complication of hypoosmolar NAC solution has been reported. We describe how a locally constructed electronic medical record (EMR) order set for IV NAC resulted in a seizure from hyponatremia due to excess free water administration.

Case Report

A 13-month-old female with no past medical history presented to a hospital after ingesting an unknown number of acetaminophen 500 mg tablets. The 4-h acetaminophen concentration was 343 mcg/mL, and she was started on IV NAC. 8.2 h into her 21-h IV NAC protocol, she developed a tonic-clonic seizure. Repeat serum sodium was 124 mEq/L, a decrease from 142 mEq/L at the time of admission. She was treated with hypertonic saline, lorazepam, and levetiracetam and had no further seizures. A brain MRI and EEG were both normal. After the seizure was stabilized, the providers noticed that the patient had receive a total of 900 mL of D5W (112.5 mL/kg) in the first 9 h of hospitalization. This was caused by a poorly constructed, restrictive, EMR order set that did not allow customization of the IV NAC preparation.

Discussion

Because the 21-h IV NAC administration involves preparation of 3 different doses infused over 3 different time intervals, an order set was developed to reduce ordering errors. However, error in its construction caused the pharmacist to prepare a solution containing too much free water, decreasing patient’s intravascular sodium and resulting in a seizure.

Conclusion

The purposes of our case report were to highlight the dangers of overreliance on EMR order sets and to recognize hyponatremic seizures as an adverse reaction of an inappropriately prepared IV NAC.     

Protection Against Acetaminophen Hepatotoxicity by Ribose-Cysteine (RibCys)

Abstract: 2(RS)-D-ribo-(1′, 2′, 3′, 4′-Tetrahydroxybutyl)thiazolidine-4(R)-carboxylic acid (Ribose-Cysteine, RibCys), a latent form of L-cysteine, releases the sulfhydryl amino acid in vivo by non-enzymatic ring opening and solvolysis. The liberated L-cysteine then stimulates hepatic glutathione biosynthesis. In the present studies, the efficacy of hepatoprotection by RibCys was evaluated to explore its potential utility as an acetaminophen (APAP) antidote. Protection was evaluated in the Swiss-Webster mouse model both by survival data as well as by quantitative histological criteria of hepatic damage. A dose-response study showed increased protection with increased intraperitoneal doses of RibCys ranging from 0.5 to 8.0 mmol/kg. RibCys administration 30 min. prior to and up to four hours after the APAP dose showed varying degrees of protection; however, the best protection was seen when RibCys was given shortly after APAP administration. A single RibCys dose given by the intraperitoneal or intravenous route gave better protection than when administered orally; however, RibCys given in three doses, one hour apart, regardless of the mode of administration, offered the best protection after an LD₉₀ dose of APAP. Overall, RibCys continues to exhibit promising protective capabilities against APAP hepatotoxicity, which may be capitalized upon in clinical overdose situations.     

N-乙酰半胱氨酸对慢性饮酒大鼠肺纤维化的干预作用的研究

目的：探讨N-乙酰半胱氨酸(NAC)对慢性饮酒大鼠肺组织的病理形态及肺组织超氧化物歧化酶(SOD)、丙二醛(MDA)含量的影响。方法：健康雄性大鼠随机分成乙醇组、乙醇+NAC组、对照组各10只,乙醇组和乙醇+NAC组每日给予乙醇液体饲料,乙醇+NAC组给予NAC 300 mg/（kg?d）。8周后处死,观察肺组织病理改变,检测肺组织中的SOD、MDA的含量。结果：乙醇组肺组织可见不同程度的肺泡壁Ⅱ型上皮细胞增生及肺泡间隔炎性细胞浸润,肺泡间隔中胶原纤维沉积增多;乙醇+NAC组胶原纤维沉积和炎性细胞浸润程度比乙醇组轻。乙醇+NAC组肺泡炎、纤维化评分低于乙醇组（P＜0.05或P＜0.01）。乙醇+NAC组肺组织匀浆SOD活力高于乙醇组,MDA含量低于乙醇组（P＜0.05）。结论：NAC提高慢性饮酒大鼠肺组织SOD的活力,降低MDA的含量,减轻肺组织的纤维化程度,对慢性饮酒大鼠肺纤维化有预防作用。     

阿魏酸乙酯对急性肺水肿模型大鼠的保护作用研究

目的:研究阿魏酸乙酯(EF)对大鼠急性肺水肿的保护作用。方法:将SD大鼠36只,随机分为6组,即空白对照组、模型组、地高辛组和EF不同剂量(25、50、100mg·kg-1)组,各组分别连续灌胃给予相应药物7d后,除空白对照组外,其余各组给予盐酸肾上腺素建立急性肺水肿模型,记录大鼠存活时间、肺动脉压(1、3、5min)及肺含水量等指标,同时进行病理学检查。结果:与模型组比较,EF各剂量组大鼠存活时间延长、肺动脉压及肺含水量降低(P<0·05),肺组织损伤减轻。结论:EF对急性肺水肿模型大鼠具有显著的保护作用。     

Effects of Salicylate on 3,4-Methylenedioxymethamphetamine (MDMA)-Induced Neurotoxicity in Rats

The drug 3,4-methylenedioxymethamphetamine (MDMA) is a serotonergic neurotoxicant that causes hyperthermia and depletion of serotonin (5-HT) and 5-hydroxy-indole-3-acetic acid (5-HIAA) in the central nervous system. Formation of neurotoxic metabolites of MDMA, e.g., 2,4,5-trihydroxy-methamphetamine and 2,4,5-trihydroxyamphetamine, involves hydroxyl and/or superoxide free radicals. The present study was designed to determine whether the hydroxyl free-radical-trapping agent salicylate could provide protection against MDMA neurotoxicity in rats. In the acute studies, sodium salicylate (12.5–400 mg/kg, calculated as free acid) was injected interperitoneally (IP) 1 h before subscutaneous (SC) injections of MDMA (20 mg/kg as base). In the chronic studies, sodium salicylate (3.1–100 mg/kg) was injected IP 1 h before repeated SC injections of MDMA (10 mg/kg as base, twice daily, at 0830 and 1730 h for 4 consecutive days). Repeated MDMA administration depleted contents of 5-HT and 5-HIAA in the frontal cortex, hippocampus and striatum. Coadministration of salicylate plus MDMA did not significantly alter MDMA-induced depletion of 5-HT and 5-HIAA in these tissues. Thus, salicylate, a hydroxyl free-radical-trapping agent, does not protect against MDMA-induced hyperthermia and depletion of 5-HT and 5-HIAA. These observations suggest that MDMA-induced neurotoxicity may occur mainly through the production of superoxide or other radicals rather than hydroxyl free radicals. Salicylate actually potentiated MDMA-induced hyperthermia and lethality, findings that might be of clinical relevance. Published by Elsevier Science Inc.     

Protective Role of Curcumin against N-Nitrosodiethylamine (NDEA)-Induced Toxicity in Rats

The present investigation was aimed at studying the possible role of curcumin against N-nitrosodiethylamine (NDEA)-induced toxicity in albino rats. Administration of NDEA to rats at a concentration of 0.1 mg/ml in drinking water ad libitum for 21 days produced toxicity in them, which was evident from histopathological changes in the rat livers, and increased levels of blood serum enzyme markers, i.e. aspartate transaminase, alanine transaminase, alkaline phosphatase, and lactate dehydrogenase. In addition, the levels of oxidative stress markers like lipid peroxidation (LPO), protein carbonyl (PCC), and glutathione-S-transferase (GST) activity were elevated and the total glutathione (GSH) content was reduced in the livers. The administration of curcumin to rats at concentrations of 10, 20, and 40 mg/ml in drinking water along with 0.1 mg/ml of NDEA for 21 days effectively suppressed NDEA-induced toxicity and also resulted in a dose-dependent reduction in the levels of blood serum enzyme markers (AST, ALT, ALP, and LDH). Moreover, LPO, PCC, and GST activity were reduced and the GSH level was increased upon the administration of curcumin along with NDEA. The results obtained for the comet assay in rat hepatocytes and blood lymphocytes showed a significant dose-dependent decrease in the mean tail length. The micronucleus assay performed on rat hepatocytes also showed a dose-dependent reduction in the frequency of micronucleated cells along with curcumin administration. These results suggest that curcumin has a protective role against NDEA-induced toxicity in albino rats.     

Antioxidant Activity of Guaiazulene and Protection Against Paracetamol Hepatotoxicity in Rats

The effect of guaiazulene, a lipophilic azulene derivative widely found in nature, on radical-mediated processes is examined. The ability of guaiazulene to inhibit rat hepatic microsomal membrane lipid peroxidation and to scavenge hydroxyl radicals, as well as to interact with 1,1-diphenyl-2-picrylhydrazyl radical (DPPH), was estimated. It was found that guaiazulene can inhibit lipid peroxidation very significantly, having an IC50 value of 9.8 μm . It can also scavenge hydroxyl radicals and interact with DPPH. The protection afforded by guaiazulene to rats with paracetamol-induced liver injury was also investigated. Paracetamol hepatotoxicity is caused by the reactive metabolite N-acetyl-p-benzoquinone imine (NAPQI), which causes oxidative stress and glutathione (GSH) depletion. Hepatic cytosolic protein, GSH, glutathione transferase and glutathione reductase levels are determined as indices of hepatic injury with or without the administration of guaiazulene. It was found that all parameters affected by paracetamol are restored to normal by guaiazulene treatment, while the administration of guaiazulene alone has no effect on the performed tests compared with the control values. It was concluded that the significant protection against paracetamol-induced GSH depletion and hepatic damage afforded by guaiazulene is probably connected with its antioxidant activity. A molecular mechanism of action of guaiazulene is suggested.     

Protection by Hydrogen Against Gamma Ray‐Induced Testicular Damage in Rats

The aim of this study was to investigate the possible protective role of hydrogen‐rich saline solution (HRSS) and WR‐2721 on the testicular damage induced by irradiation. Sprague‐Dawley rats were randomly divided into four groups. Group I served as control group. Rats in group II were exposed to the irradiation. The animals in group III and IV were injected intraperitoneally with HRSS (5 ml/kg) and WR‐2721 (200 mg/kg), respectively, 15 min. before the start of gamma irradiation. Testis weight, testis dimensions, sperm count, sperm motility, apoptosis index and biochemical assays were assessed after a 4‐day initiation of irradiation. Testis weight, testis dimensions, sperm count, sperm motility in group II were significantly lower compared with those in the control group, whereas they were higher in the HRSS and WR‐2721 group. Apoptosis index was significantly increased in group II. Treatment of rats with HRSS and WR‐2721 significantly reduced the apoptosis index. On the other hand, irradiation markedly decreased activities of SOD. Activities of SOD were significantly improved when treated with HRSS and WR‐2721. Significant increase in the MDA level was observed in group II. MDA levels of group III and IV were significantly lowered when compared with group II. HRSS also played a significant role in the recovery of serum testosterone levels. The results from this experimental study suggest that hydrogen has a possible protective effect against radiation‐induced testicular damage.     

Comparison of the Therapeutic Efficacy of 4-Methylpyrazole and N-Acetylcysteine on Acetaminophen (Paracetamol) Hepatotoxicity in Rats

Summary

Obtaining effective analgesia with a minimal erosive effect on gastric mucosal tissue has increased the consumption of acetaminophen (paracetamol), especially among the elderly. However, the hepatotoxic effects of acetaminophen have also increased. We aimed to compare the effects of 4-methylpyrazole (4-MP), N-acetylcysteine (NAC) and their combined use on the hepatotoxicity of acetaminophen in a rat model. Male Wistar Albino rats were divided into six groups. Groups 1–5 received 2000?mg/kg acetaminophen by gavage while the control group was group 6. Group 2 animals were given NAC (loading dose 140?mg/kg followed by seven doses at 4?h intervals); group 3 received 50?mg/kg 4-MP; group 4 received 200?mg/kg 4-MP; and group 5 received NAC as in group 2 plus 200?mg/kg 4-MP. Blood samples were taken for measurements of serum AST and ALT levels. The livers of the rats were removed for microscopic examination and grading of hepatic necrosis. AST and ALT levels in groups 2–5 were lower than that of group 1 (p?<?0.001), although no significant difference was noted between groups 2–5 (p?>?0.05). Higher levels of ALT were found in group 5 than in group 2 (p?<?0.05), and higher levels of AST were found in group 5 than in group 3 (p?<?0.01). Median necrosis scores were 3.36 for rats receiving acetaminophen alone (p?<?0.001, compared with groups 2–6), 1.45–1.81 for groups 2–5 (p?>?0.05, compared with each other), and 0.18 for control rats (p?<?0.001, compared with groups 1–5). In conclusion, the administration of 4-MP and/or NAC after 4?h of administering toxic dose of acetaminophen, inhibits hepatotoxicity in rats. There was no difference between the 4-MP and NAC-treated groups as reflected by comparable levels of serum transaminases and the degree of hepatic necrosis. Combining of 4-MP and NAC offers no benefit.     

舍曲林和氟西汀对慢性肺动脉高压模型大鼠的保护作用研究

目的:研究选择性5-羟色胺重吸收抑制剂(SSRI)舍曲林和氟西汀对野百合碱(MCT)诱导的慢性肺动脉高压(PAH)大鼠的保护作用。方法:40只大鼠随机分为对照组、MCT组、MCT+舍曲林(MCT+Ser)组和MCT+氟西汀(MCT+Flu)组,后3组大鼠腹腔注射MCT造模。MCT+Ser组和MCT+Flu组大鼠每天分别给予Ser和Flu,MCT组和对照组大鼠给予相应溶剂。各组大鼠常规饲养3周后检测肺动脉压、右心指数;HE染色法测定并计算非肌型动脉、部分肌型动脉及肌型动脉所占比例,比较各组肺动脉肌化程度;逆转录-聚合酶链反应法测定5-羟色胺转运体(SERT)mRNA表达变化。结果:与对照组比较,MCT组肺动脉压、右心指数、动脉肌化程度及SERTmRNA表达升高;与MCT组比较,MCT+Ser组和MCT+Flu组上述各指标均降低(P<0.05或P<0.01)。结论:Ser和Flu对MCT诱导的PAH具有抑制作用,作用机制可能与抑制SERTmRNA表达有关。     

N-乙酰半胱氨酸对体外循环致大鼠脑损伤的保护作用

目的:探讨N-乙酰半胱氨酸(NAC)对体外循环(CPB)致大鼠脑损伤的保护作用.方法:将24只成年雄性SD大鼠随机分为假手术组(S组)、CPB组(C组)、CPB+NAC组(N组),每组8只.N组在CPB预充液中加入NAC 100mg/kg,然后以20 mg/(kg·h)速度输注直到停转流,C组输注等量生理盐水.停CPB后2h,测定血浆神经元特异性烯醇化酶(NSE)、S-100β蛋白、肿瘤坏死因子-α(TNF-α)和白细胞介素-6(IL-6)水平,检测脑组织丙二醛(MDA)、谷胱甘肽过氧化物酶(GSH-px)含量,透射电镜下观察海马区神经元细胞超微结构的变化.结果:与S组比较,C组血浆NSE,C组和N组血浆S-100β蛋白、TNF-α和IL-6水平及脑组织MDA、GSH-px含量均发生一定程度的改变;且N组血浆NSE、S-100β蛋白、TNF-α和IL-6水平,脑组织MDA和GSH-px含量均显著优于C组.与S组比较,C组和N组海马区神经元细胞超微结构均有一定程度的病理学改变,且N组的损伤程度较C组明显减轻.结论:NAC可减轻CPB致大鼠脑损伤,其机制可能与抗氧化、抗炎作用有关.     

百里醌对胆管结扎大鼠氧化应激和肝损伤的保护作用研究

目的 研究百里醌对总胆管结扎大鼠氧化应激和肝损伤的保护和治疗作用. 方法 32只SD大鼠随机分为4组,分别为正常对照组、模型对照组、百里醌低剂量和高剂量组,每组8只. 在胆管结扎术前3 d起灌胃给予百里醌,低剂量组为25 mg.kg^-1,高剂量组为50 mg.kg^-1,连续2周. 处死大鼠,检测肝组织匀浆中羟脯氨酸(HP)含量和丙二醛(MDA)、超氧化物歧化酶(SOD)和谷胱甘肽过氧化物酶(GPx)的活性. 苏木精-伊红(HE)染色检测肝组织病理学改变. 结果 百里醌可显著降低胆总管结扎引起的肝脏组织内HP和MDA的含量,升高SOD和GPx含量(P<0.05). 百里醌治疗组肝脏坏死面积较模型对照组显著降低,炎性浸润程度明显降低. 结论 百里醌可以提高抗氧化损伤能力,减少肝脏氧化应激破坏,有望在胆汁淤积症患者中用于肝功能的保护.     

The Nature of 3, 4-Methylenedioxymethamphetamine (MDMA)-Induced Serotonergic Dysfunction: Evidence for and Against the Neurodegeneration Hypothesis

High doses of the recreational drug 3,4-methylenedioxymethamphetamine (MDMA, "Ecstasy") have been well-documented to reduce the expression of serotonergic markers in several forebrain regions of rats and nonhuman primates. Neuroimaging studies further suggest that at least one of these markers, the plasma membrane serotonin transporter (SERT), may also be reduced in heavy Ecstasy users. Such effects, particularly when observed in experimental animal models, have generally been interpreted as reflecting a loss of serotonergic fibers and terminals following MDMA exposure. This view has been challenged, however, based on the finding that MDMA usually does not elicit glial cell reactions known to occur in response to central nervous system (CNS) damage. The aim of this review is to address both sides of the MDMA-neurotoxicity controversy, including recent findings from our laboratory regarding the potential of MDMA to induce serotonergic damage in a rat binge model. Our data add to the growing literature implicating neuroregulatory mechanisms underlying MDMA-induced serotonergic dysfunction and questioning the need to invoke a degenerative response to explain such dysfunction.     

Mechanisms of Pulmonary Edema Induced by an Organophosphorus Compound in Anesthetized Dogs

Mechanisms of Pulmonary Edema Induced by an OrganophosphorusCompound in Anesthetized Dogs. LAINEE, P., ROBINEAU, P., GUNTIN,P., COQ, H., AND BENCHETRIT, G. (1991). Fundam. Appl. Toxtcol.17, 177-185. To determine the mechanism governing pulmonaryedema induced by an organophosphorus compound, 5-{2-diisopropylaminoethyl)-O-ethvlmethylphos-phonothiolate (VX), lung lymph flow and lymph-to-plasmaprotein concentration ratio were measured in six anesthetized,open-chest, mechanically ventilated beagle dogs before and afterintravenous injection of 6µg/kg of VX. Systemic and pulmonaryhemodynamic data (heart rate, aortic blood flow, and left atrial,systemic arterial, pulmonary arterial, and pulmonary capillarypressures) were continuously recorded. Arterial blood gasesand pH were measured every 30 min. Histological examinationsand lung water content measurements were also carried out. FollowingVX injection, lung lymph flow increased (from 109 ± 38to 179 ± 66 jil/min, p < 0.05) while lymph-to-plasmaprotein concentration ratio remained unchanged (from 0.64 ±0.14 to 0.62 ± 0.12, N.S.). Neither systemic nor pulmonaryhemodynamics were changed. Lung water content expressed as blood-freewet-to-dry weight ratio increased from 4.31 ± 0.23 to5.35 ± 0.26 (p < 0.05). Histological examinationsrevealed in many cases diffUse congestion of lungs and interstitialedema. These results suggest that VX injection induces an increasein pulmonary capillary permeability which may lead to a high-permeabilityedema.     

基因重组小肠三叶因子预防和治疗大鼠胃溃疡的研究

实验制备重组人小肠三叶因子（ｒｈＩＴＦ），用乙醇诱发大鼠胃溃疡模型研究该蛋白在体内的预防和治疗效果。先用９０％的乙醇１ｍｌ诱发溃疡，然后分不同的时间和不同的剂量尾静脉注射ｒｈＩＴＦ，以牛血清白蛋白作对照。结果发现在胃溃疡发生１ｈ前注射０．２～１ｍｇ的ｒｈＩＴＦ有明显的预防保护作用；而溃疡发生后０．５～５ｈ，静脉注射０．２～１ｍｇ的ｒｈＩＴＦ的较好的治疗作用。     

The Multifaceted Therapeutic Role of N-Acetylcysteine (NAC) in Disorders Characterized by Oxidative Stress

Oxidative stress, which results in the damage of diverse biological molecules, is a ubiquitous cellular process implicated in the etiology of many illnesses. The sulfhydryl-containing tripeptide glutathione (GSH), which is synthesized and maintained at high concentrations in all cells, is one of the mechanisms by which cells protect themselves from oxidative stress. N-acetylcysteine (NAC), a synthetic derivative of the endogenous amino acid L-cysteine and a precursor of GSH, has been used for several decades as a mucolytic and as an antidote to acetaminophen (paracetamol) poisoning. As a mucolytic, NAC breaks the disulfide bonds of heavily cross-linked mucins, thereby reducing mucus viscosity. In vitro, NAC has antifibrotic effects on lung fibroblasts. As an antidote to acetaminophen poisoning, NAC restores the hepatic GSH pool depleted in the drug detoxification process. More recently, improved knowledge of the mechanisms by which NAC acts has expanded its clinical applications. In particular, the discovery that NAC can modulate the homeostasis of glutamate has prompted studies of NAC in neuropsychiatric diseases characterized by impaired glutamate homeostasis. This narrative review provides an overview of the most relevant and recent evidence on the clinical application of NAC, with a focus on respiratory diseases, acetaminophen poisoning, disorders of the central nervous system (chronic neuropathic pain, depression, schizophrenia, bipolar disorder, and addiction), cardiovascular disease, contrast-induced nephropathy, and ophthalmology (retinitis pigmentosa).     

Improvement of the Pulmonary Absorption of (Asu1,7)-Eel Calcitonin by Various Protease Inhibitors in Rats

The effects of protease inhibitors, Na-glycocholate, bacitracin, bestatin, nafamostat mesilate and soybean trypsin inhibitor (STI) on the pulmonary absorption of (Asu^1,7)-eel calcitonin (ECT, molecular weight 3363) were investigated in rats. The pulmonary absorption of ECT was estimated by measuring its hypocalcemic effect. When ECT alone was administered into the lung, the pharmacological availability of ECT was 2.7%. Co-administration with STI or bestatin did not change the pharmacological effect of ECT. However, Na-glycocholate, bacitracin and nafamostat mesilate caused a significant hypocalcemic effect following the pulmonary absorption of ECT and a maximal effect was noted in the presence of 20 mM bacitracin, approaching the effect after intravenous administration of ECT. Bacitracin and Na-glycocholate reduced the degradation of ¹¹¹In-ECT in rat lung homogenate. Therefore, protease inhibitors effectively improved the pulmonary absorption of ECT.