Validation of Large White Pig as an animal model for the study of cannabinoids metabolism: application to the study of THC distribution in tissues

This study presents a new animal model, the Large White Pig, which was tested for studying cannabinoids metabolism. The first step has focused on determination of plasma kinetics after injection of Delta(9)-tetrahydrocannabinol (THC) at different dosages. Seven pigs received THC by intravenous injections (50, 100 or 200 microg/kg). Plasma samples were collected during 48 h. Determination of cannabinoids concentrations were performed by gas chromatography/mass spectrometry. Results showed that plasma kinetics were comparable to those reported in humans. Terminal half-life of elimination was 10.6 h and a volume of distribution of 32 l/kg was calculated. In a second step, this model was used to determine the kinetic profile of cannabinoids distribution in tissues. Eight Large White male pigs received an injection of THC (200 microg/kg). Two pigs were sacrificed 30 min after injection, two others after 2, 6 and 24 h. Different tissues were sampled: liver, kidney, heart, lung, spleen, muscle, fat, bile, blood, vitreous humor and several brain areas. The fastest THC elimination was noted in liver tissue, where it was completely eliminated in 6 h. THC concentrations decreased in brain tissue slower than in blood. The slowest THC elimination was observed for fat tissue, where the molecule was still present at significant concentrations 24 h later. After 30 min, THC concentration in different brain areas was highest in the cerebellum and lowest in the medulla oblongata. THC elimination kinetics noted in kidney, heart, spleen, muscle and lung were comparable with those observed in blood. 11-Hydroxy-THC was only found at high levels in liver. THC-COOH was less than 5 ng/g in most tissues, except in bile, where it increased for 24 h following THC injection. This study confirms, even after a unique administration, the prolonged retention of THC in brain and particularly in fat, which could be at the origin of different phenomena observed for heavy users such as prolonged detection of THC-COOH in urine or cannabis-related flashbacks. Moreover, these results support the interest for this animal model, which could be used in further studies of distribution of cannabinoids in tissues.     

Determination of paraquat in raw and formalin-fixed tissues by electron spin resonance (ESR) spectroscopy

ESR method was applied to determine paraquat levels in fresh and formalin-fixed tissues. Paraquat was converted to paraquat radical by adding sodium dithionite to tissue homogenates and detected by ESR. Paraquat levels of more than 0.2 micrograms/ml homogenate could be quantified with 0.1 ml of the homogenate. The use of manganese ions for standardization of paraquat signal enabled much more accurate ESR measurements because this ion was quite stable and its signal did not overlap that of paraquat. Even with tissues fixed in formalin, tissues paraquat levels were measureable after removing formalin from the tissue extract. This fact was verified by studying two cases; the tissues were kept in formalin for 1.5 years in case 1 and for 6.5 years in case 2. In both cases, the paraquat contents in tissues were 0.02-0.08 micrograms/g. In this way ESR is one of the most suitable methods in determining low levels of paraquat in tissues even after they were preserved in formalin for a long time.     

Vaginal fluid zinc concentration as a marker for intercourse

Zinc is present in high concentration in semen, but in low concentration in vaginal fluid. We evaluated vaginal zinc levels as a marker for intercourse by measuring precoital (greater than 11 h after intercourse) or postcoital (less than 5 h after intercourse) zinc and acid phosphatase levels in 26 specimens of vaginal fluid from 18 women. The approximate 95% reference range for zinc in precoital vaginal fluid was 1.2 to 15 micrograms/mL (mean 4.5), and in postcoital vaginal fluid 4.0 to 135 micrograms/mL (mean 24). There is an overlap between the precoital and postcoital reference ranges. Provided that the vaginal fluid zinc level is less than approximately 4.0 micrograms/mL or greater than approximately 15 micrograms/mL, vaginal fluid zinc concentration may be useful as an indicator of intercourse.     

Distribution of lidocaine and disopyramide in human blood and tissue, a case report of death caused by spinal anesthesia

An 11-year-old girl was anesthetized with hyper-baric solution of lidocaine as spinal anesthesia for an appendectomy in a surgical clinic. Respiratory arrest which occurred soon after the injection, was not discovered for a period of time. Since spontaneous respiration recovered within 2 h of intensive resuscitation, the patient was transferred to a community hospital for intensive care. Ten hours after the spinal anesthesia, she died of cardiac failure. The concentration of lidocaine in the brain was 5-10 times more than that in other tissues. The relationship between the possibility of malpractice of spinal anesthesia and tissue distribution of the drug was discussed. In addition to lidocaine, a toxic amount of disopyramide, an antiarrhythmic drug, was detected in the body. The distribution of disopyramide was also estimated, and the pharmacokinetics of disopyramide in plasma and tissues were studied experimentally in rats.     

Morphine levels in urine subsequent to poppy seed consumption

Urine morphine levels after the consumption of poppy seeds were measured in two separate trials. Maximum levels of approximately 18 micrograms/ml were found using RIA, EMIT-ST and GC methodologies. Positive immunoassay results were seen up to 60 h post-ingestion. Several different lots of seeds from various sources were assayed for morphine and found to range from 4-200 mg/kg. Differentiation of poppy seed eaters from opiate users was not possible via the identification of minor alkaloid constituents of poppy seeds. It is, however, possible to analyse opiate urines with respect to 6-O-acetylmorphine. Below the level of approximately 5 micrograms/ml total opiates, GC/MS is the method of choice for this analysis.     

A fatal case of oral ingestion of toluene

A 51-year-old male ingested orally a large quantity of toluene and died about 30 min later. The presence of toluene in body fluids and tissues was confirmed by gas chromatography and gas chromatography/mass spectrometry. Tissue distribution of toluene showed that the liver detected the highest content of toluene (433.5 micrograms/g), except for the stomach contents, followed by pancreas (88.2 micrograms/g), brain (85.3 micrograms/g), heart (62.6 micrograms/g), blood (27.6 micrograms/g), fat (12.2 micrograms/g) and finally cerebrospinal fluid (11.1 micrograms/g).     

Correlation between 'on admission' blood toluene concentrations and the presence or absence of signs and symptoms in solvent abusers

For 1 year, from June 1987 to June 1988, toluene concentrations in blood samples of patients admitted to a psychiatric hospital after inhaling solvent vapor, collected on admission and 4 h later, were analyzed by gas chromatograph. Toluene levels in the first urine samples collected after admission were also analyzed and case histories were kept listing age, sex and physical and psychiatric effects. In all, 51 cases were studied--34 males and 17 females. (1) The average age of the males was 21.4 years and of the female 16.2 years. (2) The toluene concentrations in the blood collected on admission ranged from 0.3 to 22.8 micrograms/g. (3) Physical signs were observed in 9 patients with an "on admission" blood toluene concentrations of more than 3.0 micrograms/g; twice as many subjects (18), however, with blood toluene concentration greater than 3.0 micrograms/g were without physical signs. (4) The blood toluene concentrations of three cases in the condition known as twilight state were more than 10.0 micrograms/g. (5) In 24 cases with blood toluene concentrations below 3.0 micrograms/g, there were no physical signs. (6) Five subjects with blood toluene concentrations in the 0.8-5.2 micrograms/g range showed neuropsychiatric effects; however, 23 subjects in the same blood toluene concentration range did not exhibit psychiatric effects, and none of the subjects with blood toluene concentrations greater than 5.2 micrograms/g, 15 in all, had such effects.     

Detection of thiopental and pentobarbital in head and pubic hair in a case of drug-facilitated sexual assault

The quali-quantitative determination of two barbiturates, thiopental and its metabolite pentobarbital, in head and pubic hair samples of a woman who had been sexually assaulted during hospitalisation, is reported. Hair was analysed by means of solid-phase microextraction (SPME) and gas chromatography-multiple mass spectrometry (GC-MS-MS), in chemical ionisation conditions. Thiopental and pentobarbital were found in three proximal head hair segments (sample 1A: 0.30 and 0.40 ng/mg; sample 1B: 0.20 and 0.20 ng/mg; sample 3: 0.15 and 0.20 ng/mg) and pubic hair sample. Two distal head hair segments were negative for both barbiturates. Despite the lack of collection and toxicological analysis of blood or urine samples within the hospital setting, analytical findings from hair revealed the use of the anaesthetic agent thiopental to sedate the victim quickly and deeply and commit sexual assault.     

大鼠死后心肌和肺脏微管蛋白降解规律的初探研究

目的探讨大鼠死后心肌和肺脏微管蛋白（tubulin）的降解规律与死亡时间（PMI）的关系。方法大鼠经切断股动脉致失血性休克处死后，置于RXZ智能型人工气候箱内，实验条件设定为：20℃恒温，湿度50％。分别于大鼠死后0、1、2、3、5和7d时剖取心肌和肺脏组织，应用Western-Blot法检测心肌和肺脏tubulin的含量，并对所得数据进行统计学分析。结果Tubulin在正常大鼠心肌和肺内高表达，死后1d时其含量已开始下降，至死后7d时仍可检测到微管蛋白的存在，但tubulin在肺脏内的降解速度快于心肌。两种组织内tubulin含量随PMI变化的回归方程及相关系数分别为：心肌Y=-1726．Ix＋14083，r=0．9684；肺脏Y=-1439．89x＋12041，r=0．9808。结论大鼠死后心肌和肺脏tubulin的含量逐渐减少，与PMI具有相关性。     

The influence of storage temperature and chemical preservation on the stability of succinylcholine in canine tissue

Succinylcholine (SCh) has been detected six months postmortem in liver, kidney, and injection site muscle of rats given 10 to 200 mg/kg by intramuscular injection. SCh stability was studied in canine tissue to evaluate three storage temperatures and two chemical preservatives at three time periods after injection. Nine mongrel dogs weighing 17.2 to 28 kg were divided equally into three groups and administered either 0.5, 1.0, or 5.0 mg SCh/kg intravenously into the cephalic vein. Liver, kidney, and gastrocnemius muscle were removed 90 min post-injection and divided into twelve portions. Each portion was treated with embalming fluid, physostigmine, the combination (50/50), or nothing. Chemically treated tissues and nontreated tissues were then stored at either 27, 5, or -20 degrees C for a period of up to forty days. Tissue portions were analyzed using ion-pair extraction, chemical demethylation, and gas chromatography with nitrogen phosphorous detection. Stability of SCh was greatest for samples stored at -20 degrees C and preserved with the combination of embalming fluid plus physostigmine. Kidney concentrations of SCh were significantly higher than those in liver or muscle at all doses. SCh was detected 24 h post-injection in all cases. By 40 days, only trace amounts of SCh, if any, could be detected in samples stored at room temperature with no chemical preservatives.     

乌头碱在家兔体内的代谢动力学初步研究

本文应用甲醇-0.05mol/L碳酸铵水溶液-二氯甲烷(90:10:2)作流动相,在YWGC_(18)H_(37)反相键合相色谱柱上分离乌头碱和内标,用紫外分光检测器在235nm外定量,改进了动物组织内痕量乌头碱的HPLC检测法。运用该法检测家兔静脉注射乌头碱后的血毒物浓度,初步研究了乌头碱在家兔体内的代谢动力学过程,表明其体内过程符合开放二室模型,T_(1/2α)=1.4682min,T_(1/2β)=34.1379min。体内乌头碱可以原形由尿和胆汁中排出,但以前6h尿排泄为主。     

Analysis of methylbenactyzium bromide in human urine by thin-layer chromatography and pyrolysis gas chromatography.

A rapid and simple method of utilizing thin-layer chromatography (TLC) and pyrolysis gas chromatography (PyGC) for the identification and determination of methylbenactyzium bromide in human urine was studied in this report. Methylbenactyzium bromide was extracted from urine with ODS-cartridge (Sep-Pak C18), then spotted onto a silica gel 60 F254 TLC plate. After development, the separated spot of methylbenactyzium bromide was scraped and wrapped with a ferromagnetic foil without extraction by any organic solvents. The sample was applied into PyGC analysis. The optimum temperature for pyrolysis was 590 degrees C. The main degradation product of methylbenactyzium bromide was identified as diphenylmethane in this procedure by gas chromatography/mass spectrometry (GC/MS). A calibration graph prepared by absolute calibration method showed a good linearity over the concentration range of 1-75 micrograms/spot for methylbenactyzium bromide. The coefficient of variation obtained for eleven replicate analyses of the 3 micrograms/spot of standard methylbenactyzium bromide was 3.8%. The detection limit of this compound by this procedure was 0.1 micrograms/spot.     

Peroxidase activity in traumatic skin lesions

Peroxidase activity was determined in experimental compression-excoriation lesions and incision wounds of rat skin after different periods of vital time. The peroxidase enzyme was extracted from the tissues by homogenization in 0.5% cetyltrimethylammoniumbromide, and the enzyme activity was measured from the supernatant by o-dianisidine-H2O2 assay. In the blood of the rats a mean activity of approx. 5.26 +/- 1.11 U/g dry weight was observed. In the control specimens of the skin the activity was very low and generally below the detection limit of the methods used. In 30-min-old compression-excoriation lesions the mean peroxidase activity was 0.38 +/- 0.21 U/g dry weight. In lesions older than 30 min the activity started to increase rapidly. In 4-h-old compression-excoriation lesions it was 10 times higher than the 30-min level and was 40 times higher in 12-h-old lesions and 70-100 times higher in 1-3-day-old compression-excoriation lesions, respectively. In 30-min-old incision wounds the mean peroxidase activity was 0.65 +/- 0.37 U/g dry weight. The increase of the activity compared with the 30-min level was even faster in the incision wounds: in 4-h-old wounds the mean activity was 50 times higher, in 12-h-old wounds 200 times higher and in those of 1-5 days it was several hundreds of times higher. Compression-excoriation lesions made after death showed activity similar to the control specimens. Postmortem autolysis at +22 degrees C resulted in a loss of the enzyme activity in 1-day-old compression-excoriation lesions so that after 3 days approx. 80% remained, and after 5 and 7 days approx. 40% was present. After 3 days of autolysis at +4 degrees C, nearly 100% of the activity remained and approx. 90% was present after 5 and 7 days of autolysis. Increased peroxidase activity was also detectable in human vital excoriations in the specimens which were taken in autopsies several days postmortem.     

HPLC-MS/MS法检测血液中甲卡西酮及其代谢物

目的 建立同时检测血液中新精神活性物质甲卡西酮及其代谢物卡西酮、麻黄碱和伪麻黄碱含量的高效液相色谱-串联质谱方法 ,验证甲卡西酮在大鼠体内的代谢物.方法 血液样品中加入内标物甲卡西酮-D3,经甲醇提取后采用InfinityLab Poroshell 120 Chiral-V型色谱柱分离,以甲醇和乙腈混合流动相恒比洗脱,...     

直接进样气相色谱法测定全血中乙醇的含量

目的建立一种直接进样气相色谱法检测全血中的乙醇。方法全血经硫酸铝钾沉淀蛋白,加入内标异丙醇后,用直接进样气相色谱法进行检测,FID为检测器,用保留时间定性,内标标准曲线法定量。结果该方法线性范围为0.2-1.4mg/m L,相关系数R=0.999 3,总分析时间不超过5min,最低检测限为0.01mg/m L,相对标准偏差（RSD）〈5%,平均回收率为92.3%;所建立的方法与顶空气相色谱（HS-GC）法比较相对偏差（RD）〈10%。结论该方法可用于全血中乙醇的检测。     

大鼠实验性肺脂肪栓塞的病理学研究

取大鼠皮下脂肪乳化后作自身静脉注射,观察自身脂肪栓子对肺血管的光镜和电镜变化。结果表明,注射后1天肺小动脉及毛细血管内充满大量脂滴。4天时达高峰并伴有肺水肿、灶性出血以及单核细胞吞噬脂滴,中性、嗜酸性白细胞的浸润。7天后脂滴逐渐消失、未见其他脏器栓塞。     

Postmortem redistribution of digoxin in rats

Adult male Wistar rats were treated with either 0.1 or 3 mg/kg body weight X day of digoxin for five days, then killed and stored at 4 degrees C for 12 h in an attempt to mimic the normal preautopsy procedures in our hospital. In rats treated with 0.1 mg/kg body weight X day, the antemortem serum digoxin concentrations (SDC) were 1.1 +/- 0.4 ng/mL while the 12-h postmortem concentration was markedly increased (16.3 +/- 5.9 ng/mL) (P less than 0.01). In rats treated with 3 mg/kg body weight X day, SDC was not changed significantly (11.2 +/- 4.8 ng/mL antemortem and 13.3 +/- 6 ng/mL postmortem). Postmortem redistribution of digoxin was assessed by injection of 125I-labelled digoxin with or without pretreatment with the unlabelled drug. The results indicate that after death passive redistribution of digoxin may take place. When the SDC are within the therapeutic or low toxic range, digoxin may reenter the blood. High antemortem serum concentrations of digoxin may prevent such passive redistribution. Therefore, antemortem digoxin intoxication cannot be reliably inferred on the basis of high postmortem levels of the drug. Digoxin intoxication can be ruled out when postmortem SDC remain within the therapeutic range. The above changes cast doubt on some of the forensic and cardiologic literature, which has in the past been based on incorrect assumptions concerning postmortem behavior of digoxin.     

Distribution profile of 2,5-dimethoxy-4-bromoamphetamine (DOB) in rats after oral and subcutaneous doses

2,5-Dimethoxy-4-bromoamphetamine (DOB) is one of the potent hallucinogenic phenylalkylamines, whose ingestion has already caused several deaths reported all over the world. However, there is unsufficient information on DOB properties based on controlled pharmacokinetic studies available. The aim of this study was to clarify the distribution profile of DOB and its phenolic metabolite 2-methoxy-5-hydroxy-4-bromoamphetamine (2M5H4BA) in blood and biological tissues of experimental rats. The rats were administered a 20 mg/kg dose of DOB·HCl by oral ingestion or subcutaneous injection. Plasma and brain, liver and lung tissues were collected at 0.5, 1, 2, 4, 8, 16, and 32 h after dosing (three animals per time point). The samples were prepared by a liquid–liquid extraction procedure and the extracts were assayed by GC–MS. After per oral application, DOB peak plasma level of 320 ng/mL was reached after one-hour post dosing as well as 2M5H4BA peak concentration of 203 ng/mL. A rapid phase of DOB absorption, 2M5H4BA formation and their tissue distribution during the first two hours after application were followed by a slow decrease rate of the elimination process until 32 h. After subcutaneous application, high plasma levels of the unchanged parent drug and relatively reduced formation of its metabolite 2M5H4BA were observed. DOB maximum plasma concentration of 1143 ng/mL was reached after one-hour post application, whereas its metabolite peak level after 8 h was 213 ng/mL. The concentration profiles of both compounds in plasma after per oral and subcutaneous administration revealed the existence of significant first pass effect after per oral administration that significantly affected DOB bioavailability. DOB tissue concentrations exceeded plasma and the highest values were found in the lungs, where drug accumulation occurred with prolonged retention till 32 h after subcutaneous dose. Although the plasma/tissue transfer was more effective for the lipophilic parent drug than for its hydroxylated metabolite 2M5H4BA, the metabolite tissue levels were significant. The hallucinogenic potential of 2M5H4BA appearing in brain remains unclear as nothing is known about its pharmacological activity at present.     

Lung embolism with liquid silicone

A lung embolism was reported in a case involving death following repeated injections of liquid silicone for aesthetic reasons. The liquid extracted from the sites of injection was identified as methylsilicone using infrared spectrophotometry, and the presence of silicone in vacuoles in the lung was verified by scanning electron microscopy with energy dispersive X-ray analysis (EDXA). A study has been carried out with rats after intravenous and subcutaneous injections of methylsilicone.     

Determination of paraquat in tissue using ion-pair chromatography in conjunction with spectrophotometry

Homogenized tissue was deproteinized with sulfuric acid. Paraquat in the supernatant was quantificated directly with the dithionite reagent (step 1) or concentrated by the XAD-2 column chromatographic technique before paraquat determination (step 2). Tissue paraquat levels in the range of 0.01-75 mg/kg could be quantificated by second-derivative or zero-order spectroscopy using 2.5 g of tissues. The sensitivity could be increased tenfold by using 25 g of tissue samples. The coefficients of variation of within-run and day-to-day precisions of spiked paraquat in tissue homogenates were below 5% at concentrations of 10.0, 1.0 and 0.1 mg/kg, respectively. The recoveries of the spiked paraquat in tissues ranging from 0.1-10 mg/kg were 91% by step 1 and 74% by step 2. Using these simple methods, steps 1 and 2, the paraquat concentrations in the psoas muscle, liver, lung and kidneys of a swine dosed with 0.16 g/kg of paraquat were investigated. The results were in close agreement with those of the TCA deproteinization method followed by cation-resin column chromatography. The proposed method offers the advantages of simplicity, rapidity, reasonable sensitivity and a wide range of concentrations.