Do all stoneflies nymphs have respiratory proteins? Further data on the presence of hemocyanin in the larval stages of plecoptera species

Contrary to what was assumed regarding the presence of respiratory proteins in insects, a functional hemocyanin was recently found in larvae and adults of the stoneflies species Perla marginata , whereas in the close species Perla grandis , hemocyanin functionality was deduced from sequence data. In order to verify if the presence of this ancient trait is widespread within the order and to investigate why stoneflies have maintained it, we have extended the search for hemocyanin to species of other Plecoptera families. In particular, we assessed the presence of hemocyanin in the larval stage of nine Plecoptera species, belonging to six of the seven families of the European stonefly-fauna, and analyzed its potential functionality as deduced by sequence data. We cloned and sequenced the corresponding cDNAs and studied their expression with RT-PCR technique. Moreover, we performed homology studies using the deduced amino acid sequences. On the basis of our analysis, we hypothesized a functional role of the hemocyanin only for two species: Dinocras cephalotes and Isoperla grammatica (Perloidea). In all the investigated Nemouroidea and in Siphonoperla torrentium (Perloidea), this protein may have been lost. Larval size, life-cycle length, trophic role and environmental induction are discussed as possible explanations of these different physiological requirements.     

Inhalation exposure to ambient polycyclic aromatic hydrocarbons and lung cancer risk of Chinese population

An Euler atmospheric transport model (Canadian Model for Environmental Transport of Organochlorine Pesticides, CanMETOP) was applied and validated to estimate polycyclic aromatic hydrocarbon (PAH) ambient air concentrations at ground level in China based on a high-resolution emission inventory. The results were used to evaluate lung cancer risk for the Chinese population caused by inhalation exposure to PAHs. The uncertainties of the transport model, exposure, and risk analysis were assessed by using Monte Carlo simulation, taking into consideration the variation in PAH emission, aerosol and OH radical concentrations, dry deposition, respiration rate, and genetic susceptibility. The average benzo[a]pyrene equivalent concentration (B[a]P_eq) was 2.43 [≈1.29–4.50 as interquartile range (IR)] ng/m³. The population-weighted B[a]P_eq was 7.64 (IR, ≈4.05–14.1) ng/m³ because of the spatial overlap of the emissions and population density. It was estimated that 5.8% (IR, ≈2.0–11%) of China''s land area, where 30% (IR, ≈17–43%) of the population lives, exceeded the national ambient B[a]P_eq standard of 10 ng/m³. Taking into consideration the variation in exposure concentration, respiration rate, and susceptibility, the overall population attributable fraction (PAF) for lung cancer caused by inhalation exposure to PAHs was 1.6% (IR, ≈0.91–2.6%), corresponding to an excess annual lung cancer incidence rate of 0.65 × 10⁻⁵. Although the spatial variability was high, the lung cancer risk in eastern China was higher than in western China, and populations in major cities had a higher risk of lung cancer than rural areas. An extremely high PAF of >44% was estimated in isolated locations near small-scale coke oven operations.     

Disequilibrium Between Alveolar and End-Pulmonary-Capillary O<Subscript>2</Subscript> Tension in Altitude Hypoxia and Respiratory Disease: An Update of a Mathematical Model of Human Respiration at Altitude

We have previously formulated and validated a mathematical model specifically designed to describe human respiratory behavior at altitude. In that model, we assumed equality of alveolar and end-pulmonary-capillary oxygen tensions. However, this equality may not hold true during rapid and prolonged changes to high altitudes producing severe hypoxia as can occur in aircraft cabin decompressions and in some respiratory diseases. We currently investigate this possibility by modifying our previous model to include the dynamics of oxygen exchange across the pulmonary capillary. The updated model was validated against limited experimental data on ventilation and gas tensions in various altitude-decompression scenarios. The updated model predicts that during rapid and sustained decompressions to high altitudes the disequilibrium of gas tensions between alveolar gas and capillary blood could be 10 Torr, or larger. Neglecting this effect underestimates the severity of a decompression and its potential to produce unconsciousness and subsequent brain damage. In light of these results, we also examined the effect of this disequilibrium on the diminished oxygen diffusion capacity that can occur in some respiratory diseases. We found that decreases in diffusion capacity which would have minimal effects at sea level produced significant disequilibrium of gas tensions and a large fall in hemoglobin oxygen saturation at a cabin altitude of 4000–8000 ft. As demonstrated, this new model could serve as an important tool to examine the important physiological consequences of decompression scenarios in aircraft and the pathophysiological situations in which the equilibrium of gas tensions along the pulmonary capillary are particularly critical.     

经鼻双水平气道内正压通气对重叠综合征患者血浆内皮素1的影响

目的探讨经鼻双水平气道内正压通气（nBiPAP）对重叠综合征（OS）患者血浆内皮素-1（ET-1）含量的影响。方法实验分为两组：慢性阻塞性肺疾病（COPD）组20例；重叠综合征组25例，用放免法测定COPD组及重叠综合征患者BiPAP治疗前后血浆ET-1浓度变化。分析其与睡眠期血氧饱和度的相关性。结果（1）BiPAP治疗前重叠综合征患者血浆ET-1浓度明显高于COPD组；（2）BiPAP治疗后重叠综合征患者血浆ET-1浓度较治疗前下降，差异有统计学意义；（3）血浆ET-1浓度与睡眠期平均血氧饱和度呈负相关（r=0．4979，P〈0．05）。结论经鼻双水平气道内正压通气为治疗重叠综合征的有效方法，其发挥作用可通过增加血氧饱和度，降低ET-1水平。     

比例辅助通气、压力支持通气对健康和急性肺损伤犬心肺功能影响的比较

目的 比较比例辅助通气(PAV)和压力支持通气(PSV)模式对健康和急性肺损伤(ALI)犬心肺功能的影响.方法 对10例健康和急性肺损伤犬先用间歇正压通气(IPPV)模式通气,同时计算弹性阻力(Ers)和粘性阻力(Rrs),然后将模式改为PAV,设置辅助比例60%,稳定后记录呼吸力学、血气和血流动力学参数的变化.再将模式改为PSV,设置支持压力分别使得气道峰压(Ppeak)和潮气量与PAV时相似.稳定后记录各项参数.结果 对于健康犬,PSV与PAV60%潮气量相同时其平均气道压(mPaw)、呼吸机呼吸功(WOBv)较PAV60%时高,差异有统计学意义,余各指标间差异无统计学意义.PSV和PAV比较,对血流动力学影响差异无统计学意义.对于ALI犬,PSV潮气量与PAV60%相同时,其Ppeak和mPaw较PAV60%高,差异有统计学意义,余指标差异无统计学意义.对血流动力学的影响,PSV潮气量与PAV60%相同时,其肺毛细血管楔压(PCWP)较PAV60%增高,差异有统计学意义.结论 PAV与PSV相比,其气道压力低,对血流动力学影响较小.     

呼吸控制和人工胸水在肝癌HIFU治疗中的应用

目的观察呼吸控制和人工胸水在43例肝癌病人的HIFU治疗中的应用。方法43例肝肿瘤患者在气管插管全麻下，右侧胸腔注入生理盐水形成人工胸水。监测HIFU治疗前后的血气分析，HIFU治疗时持续监测ECG、MAP、HR、SpO2、PETCO2；治疗后3—7d内胸部X片观察胸水转归。结果所有患者在人工胸水和呼吸控制下进行HIFU治疗期间血气和血液动力学各指标均保持稳定，人工胸水在7d内各例患者均完全吸收。结论人工胸水及呼吸控制是一种安全的方法，有助于提高HIFU治疗的有效率，并拓宽HIFU治疗的适应范围。     

氯胺酮的抗惊厥作用及对兔呼吸、血压的影响

目的观察氯胺酮在治疗士的宁惊厥时对兔呼吸、循环的影响。方法健康成年家兔50只,雌雄不拘,随机分成K1.25、K2.5、K5.0、NS和PB5.0组,每组10只。清醒状态局部麻醉作用下行股动脉插管、剑突穿线,测定兔股动脉血压和呼吸频率。兔耳缘静脉注射士的宁0.25 mg/kg制作惊厥模型,强直惊厥出现后立即静脉注射治疗药物。观察各组兔的死亡数、强直持续时间、呼吸频率和股动脉血压情况。结果氯胺酮大、中、小3个剂量组与NS组和PB5.0组相比,兔强直持续期明显缩短（P〈0.01）,且呈剂量依赖性（r=-0.8696,P〈0.05）。K2.5、K5.0和PB5.0组死亡均为零。氯胺酮各剂量组呼吸频率在注药后2-5 min内比基础值提高（P〈0.01）。氯胺酮各剂量组股动脉血压在注药后2、5 min时高于PB5.0组（P〈0.05）,在5、10 min时高于NS组（P〈0.05）。结论氯胺酮能对抗士的宁诱发的惊厥,明显改善惊厥兔的呼吸、循环。     

Di-(2-ethylhexyl)-phthalate as plasticizer in PVC respiratory tubing systems: indications of hazardous effects on pulmonary function in mechanically ventilated,preterm infants

Several PVC medical devices contain the plasticizer Di-(2-ethylhexyl)-phthalate (DEHP) in high concentration. Taken systemically DEHP only has minor toxic effects in the human organism. In three preterm infants artifically ventilated with PVC respiratory tubes unusual lung disorders resembling those observed in hyaline membrane disease, verified both clinically and radiologically, were observed during the fourth week of life. It was assumed that these lung disorders were causally related to the exposure to high doses of DEHP, which was released from the walls of the respiratory tubes. DEHP was found in the lung tissue of one patient who died of pneumothorax soon after birth after being artifically ventilated. It is strongly recommended that for disposable PVC respiratory devices the plasticizer DEHP should be used with more restrictions.Abbreviations PVC polyvinylchloride - DEHP di-(ethylhexyl)-phthalate - MEHP mono-(ethylhexyl)-phthalate - GCMS gas chromatography — mass spectrometry     

Inspiratory augmenting bulbospinal neurons express both glutamatergic and enkephalinergic phenotypes

Many of the inspiratory augmenting (I-AUG) neurons of the rostral ventral respiratory group (rVRG) are premotor neurons that excite phrenic motor neurons during inspiration, probably by releasing glutamate. In the present study, we demonstrate that these neurons are indeed glutamatergic, in that their cell bodies contain vesicular glutamate transporter-2 (VGLUT2) mRNA and spinal terminals from neurons in the region of the rVRG contain VGLUT2 protein. We also demonstrate by using parallel in situ hybridization and immunocytochemical evidence that most rVRG inspiratory premotor neurons are enkephalinergic. After iontophoretic deposits of biotinylated dextran amine (BDA) in the area of the rVRG, many BDA-labeled terminals in the ventral horn of cervical spinal cord (C4-C5) were immunoreactive for enkephalin and VGLUT2. Injections of Fluoro-Gold amidst phrenic motor neurons in C4-C5 labeled neurons in the area of the rVRG that contained both VGLUT2 mRNA and preproenkephalin (PPE) mRNA as revealed by double in situ hybridization. Thirty-eight bulbospinal I-AUG neurons were recorded in the rVRG and filled with biotinamide by using the juxtacellular labeling technique. Every biotinamide-filled cell tested was positively labeled for VGLUT2 mRNA (n = 14), and most of the cells tested in a separate population exhibited PPE mRNA (16/18). We conclude that most of the phrenic inspiratory premotor neurons of the rVRG are glutamatergic neurons that may also release enkephalins.     

A group of glutamatergic interneurons expressing high levels of both neurokinin-1 receptors and somatostatin identifies the region of the pre-Bötzinger complex

The pre-B?tzinger complex (pre-B?tC) is a physiologically defined group of ventrolateral medullary neurons that plays a central role in respiratory rhythm generation. These cells are located in a portion of the rostral ventrolateral medulla (RVLM) that is difficult to identify precisely for lack of a specific marker. We sought to determine whether somatostatin (SST) might be a marker for this region. The rat pre-B?tC area was defined as a 500-microm-long segment of ventrolateral medulla coextensive with the ventral respiratory group. This region was identified by juxtacellular labeling of neurons with respiratory-related activity and by its location rostral to the phrenic premotor neurons. It contained most of the SST-ir neuronal somata of the RVLM. These cells were small (107 microm(2)) and expressed high levels of preprosomatostatin mRNA. They were strongly neurokinin 1 receptor (NK1R)-ir and were selectively destroyed by saporin conjugated with an NK1R agonist (SSP-SAP). Most SST-ir neurons (>90%) contained vesicular glutamate transporter 2 (VGLUT2) mRNA, and terminals immunoreactive for SST and VGLUT2 protein were found in their midst. Few SST-ir neurons contained GAD-67 mRNA (<1%) or preproenkephalin mRNA (6%). Retrograde labeling experiments demonstrated that over 75% of the SST-ir neurons project to the contralateral pre-B?tC area, but none projects to the spinal cord. In conclusion, the RVLM contains many neurons that express preprosomatostatin mRNA. A subgroup of these cells contains high levels of SST and NK1R immunoreactivity in their somata. These glutamatergic interneurons identify a narrow region of the RVLM that appears to be coextensive with the pre-B?tC of adult rats.