Fatal combined anileridine-pethidine poisoning. A gas chromatography,thin layer chromatography and mass spectrometry investigation

Summary Anileridine and pethidine were established by gas and thin layer chromatography and mass spectroscopy. In the mass spectrum the main peak of anileridine is found at m/e 246 and that of pethidine at m/e 71. The determination was made by gas chromatography from the blood, urine, liver, muscle and stomach contents.

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Zusammenfassung Anileridin und Pethidin wurden mittels Gas- und Dünnschicht-chromatographie sowie massenspektroskopisch festgestellt. Im Massenspektrum liegen die Hauptspitze von Anileridin bei m/e 246 und diejenige von Pethidin bei m/e 71. Die Bestimmung erfolgte gaschromatographisch aus Blut, Harn, Leber, Muskel und Mageninhalt.

     

Evaluation of dopamine metabolism in rat striatum by a gas chromatographic technique

Dopamine metabolism in rat striatum was evaluated by gas chromatographic quantitation of 3,4-dihydroxy-phenylacetic acid (DOPAC) and homovanillic acid (HVA). The level of DOPAC (5.21 nmoles/g ± 0.40 S.E.M., N = 12) exceeded that of HVA (3.63 nmoles/g ± 0.25 S.E.M., N = 12). 2 hr following administration of probenecid (200 mg/kg i.p.) the level of striatal HVA was approximately doubled whereas the level of DOPAC was not significantly elevated. Parggline (75 mg/kg i.p.) produced a rapid depletion of DOPAC and HVA. The rate of disappearance of DOPAC (t^1/2 = 10 min) exceeded that of HVA (t^1/2 = 18 min). Rates of metabolite formation were computed assuming steady state kinetics. The rate of formation of DOPAC (20.5 nmoles/g/hr) was much greater than that of HVA (10.1 nmoles/g/hr). We conclude that DOPAC is the major dopamine metabolite in rat striatum and that its measurement may provide the best index of functional of neuronal activity in this species.     

Metabolism and pharmacokinetics of vinyl acetate

The hydrolysis of vinyl acetate (formation of acetic acid) has been studied in vitro with rat liver and lung microsomes, rat and human plasma and purified esterases (such as acetylcholine esterase, butyrylcholine esterase, carboxyl esterase). Characterization of the kinetic parameters revealed that rat liver microsomes and purified carboxyl esterase (from porcine liver) displayed the highest activity.In order to establish the rate of metabolism of vinyl acetate in vivo, rats were exposed in closed desiccator jar chambers, and gas uptake kinetics were studied. The decay of vinyl acetate was dose-dependent, indicating possible saturation of metabolic pathway(s). The maximal clearance (at lower concentrations) of vinyl acetate from the system (30 000 ml/h per kg body weight) was similar to the maximal ventilation rate in this species. This indicated that under conditions when metabolic enzymes are not saturated the metabolic rate is mainly determined by pulmonary uptake.The exposure of rats to vinyl acetate resulted in a transient exhalation of significant amounts of acetaldehyde into the closed exposure system. This indicates the presence of this metabolic intermediate of vinyl acetate in the organism in vivo.     

Development of a novel polyimide hollow-fiber oxygenator

We have developed a membrane oxygenator using a novel asymmetric polyimide hollow fiber. The hollow fibers are prepared using a dry/wet phase-inversion process. The gas transfer rates of O(2) and CO(2) through the hollow fibers are investigated in gas-gas and gas-liquid systems. The polyimide hollow fiber has an asymmetric structure characterized by the presence of macrovoids, and the outer diameter of the hollow fiber is 330 microm. It is found that the polyimide hollow-fiber oxygenator can enhance the gas transfer rates of O(2) and CO(2), and that the hollow fiber provides excellent blood compatibility in vitro and in vivo.     

Increased urinary F(2)-isoprostanes levels in the patients with Alzheimer's disease

Isoprostanes, novel markers of oxidative injury, are generated by the free radical-mediated peroxidation of arachidonic acid (AA). They are thought to be important in the pathogenesis of neurodegenerative diseases such as Alzheimer's disease (AD). Using gas chromatography-mass spectrometry (GC-MS), we investigated the alteration of urinary F(2)-isoprostanes in AD patients compared to that of healthy subjects. Our results show that the levels of urinary F(2)-isoprostanes, sum of the prostaglandin F(2 alpha) isomer; prostaglandin F(2 alpha) (PGF(2 alpha)), prostaglandin F(2 beta) (PGF(2 beta)), and 8-isoprostaglandin F(2 alpha) (8-isoPGF(2 alpha)), significantly increased in AD patients (P < 0.05). The concentration of urinary 8-isoPGF(2 alpha), one of the biomarkers of oxidative stress, was not significantly different between 34 AD patients and 20 age-matched controls (P > 0.05). The PGF(2 alpha), formed by endoperoxide reductase from PGH(2), was significantly increased in AD patients, when compared with the levels of the normal controls (P < 0.05). The PGF(2 alpha), an enzymatic product of arachidonic acid, may affect the pathogenesis of AD. In addition, urinary F(2)-isoprostanes can play an important role as a biomarker in AD.     

Validity and reliability of three commercially available breath-by-breath respiratory systems

Information concerning the validity and reliability of commercial on-line gas analysis systems is limited. The aim of this study was to provide a comparison of the validity and reliability of three on-line systems (Oxycon Alpha, Oxycon Pro and Pulmolab EX670) with that of Douglas bags. Two separate studies were conducted. In study 1, the three gas analysis systems were compared with Douglas bags using a metabolic simulator over four increases in ventilation. In study 2, ten subjects were split into equal groups exercising at 100 W or 150 W for 85 min on three separate occasions. Each system was used twice per visit. Study 1 demonstrated that the Oxycon Alpha and Douglas bags produced similar respiratory values over all levels of ventilation. The Oxycon Pro tended to slightly overestimate mean expiratory flow ( ), oxygen uptake ( ), carbon dioxide production ( ) and respiratory exchange ratio (RER) at the higher ventilations. The Pulmolab produced large overestimations at all ventilations for and RER (up to 26.3% away from expectations), whilst values for , and were slightly underestimated at higher ventilations (up to 7.5% from expectations). The results of study 2 support the findings of study 1, with the Oxycon Pro and Oxycon Alpha producing similar results compared to Douglas bags for , and RER. The coefficients of variation for and measured using Douglas bags, Oxycon Pro and Oxycon Alpha were 3.3–5.1%, 4.7–7.0% and 4.5–6.3%, respectively, whilst that for the Pulmolab was highly variable (26.8–45.8%). The exercise study showed the Oxycon Pro and Oxycon Alpha to be both valid and reliable on-line systems for the measurement of parameters of respiration, at least at workloads up to 150 W. Electronic Publication     

A benign cause of surgical emphysema

Surgical emphysema affecting a limb is rare. A case is reported of subcutaneous emphysema involving the upper limb resulting from a trivial laceration 2 cm in size on the third interdigital space on the dorsum of the right hand. Gas can form in soft tissues from a wound infection with a gas-forming organism or from a variety of non-infectious causes. One mechanism involves the skin wound acting as a flap valve leading to air being trapped in soft tissues.Institute of origin, Whipps Cross University Hospital.     

Involvement of Gas7 in nerve growth factor-independent and dependent cell processes in PC12 cells

Gas7, a growth arrest-specific gene originally isolated from serum-starved mouse fibroblast cells, is expressed in vivo predominantly in the brain and is required for neurite formation in cultured mouse cerebellar neurons (Ju et al. [1998] Proc. Natl. Acad. Sci. USA 95: 11423-11428). Here we report that Gas7 plays a key role in the morphological differentiation of PC12 preneuronal rat pheochromocytoma cells (PC12 cells). We found that overexpression of murine Gas7 in PC12 cells leads to an expanded cell morphology and promotes spike-like cell processes that resemble the early stages of neurite formation. These processes undergo elongation upon addition of nerve growth factor (NGF). We also found that the addition of NGF induces the production of endogenous rat-Gas7 (rGas7), which is transiently elevated prior to the appearance of NGF-promoted neurite outgrowths. Furthermore, inhibition of endogenous rGas7 production by antisense nucleotides complimentary to the translation initiation region of a rGas7 cDNA (AJ131902) reduces the NGF-promoted neurite outgrowths. Our results demonstrate that Gas7 by itself influences early cell morphological development and likely functions as an early-stage intermediary in NGF-induced neuronal differentiation of PC12 culture cells.     

气相色谱法测定复方牙痛酊中乙酸龙脑酯和樟脑的含量

目的采用毛细管气相色谱法同时测定复方牙痛酊中樟脑和乙酸龙脑酯的含量,建立复方牙痛酊质量控制体系。方法以水杨酸甲酯为内标,石英毛细管柱OV-1701(30 m×0.32 mm,0.25μm)为固定相,氮气为载气,FID检测器。结果在该色谱条件下,乙酸龙脑酯和樟脑分别在0.0295~0.295 mg.ml-1,0.012 72~0.127 2 mg.ml-1的浓度范围内线性关系良好(r>0.999 5);平均回收率分别为97.2%,98.1%,RSD分别为2.35%,2.14%(n=6)。结论该方法简单、灵敏、快速、回收率和重现性好,可以作为复方牙痛酊的质量控制标准。     

塑料成品及其稳定剂中三甲基氯化锡的气相色谱-质谱联用测定法

目的　建立塑料稳定剂及塑料成品中三甲基氯化锡的测定方法。方法　按照有关检测方法的研制规范的要求,研究了色谱条件的选择、样品的处理方法、回收率试验、萃取效率试验、方法的线性范围及检出限、方法的精密度等指标。结果　采用HP -5MS弹性毛细管石英柱(3 0m×0 .3 2mm×0 .2 5 μm)能将三甲基氯化锡和其他可能共存的有机锡完全分离。三甲基氯化锡含量在0 .0 5～2 40mg/kg范围内呈线性关系,相关系数为0 .9987,方法的最低检出浓度为0 .0 5mg/kg。对浓度为0 .4、4.0、40 .0 μg/ml配制样,方法的相对标准偏差(RSD )为4.0 %～8.2 %。方法的回收率为90 .5 %～97.5 %。塑料成品的萃取效率可达到90 %以上,样品在密封容器内至少可保存14d。结论　该方法各项指标均达到有关检测方法的研制规范的要求,适用于塑料稳定剂及塑料成品中三甲基氯化锡的检测