Effects of profound hypothermia on the blood-brain barrier permeability in acute and chronically ethanol treated rats

This study examines the effects of profound hypothermia on the blood-brain barrier (BBB) permeability in ethanol administrated rats. Vascular permeability to intravenously injected Evans blue (EB) was quantitatively examined in the brain regions of rats. Rats were treated with ethanol acute and chronically. Rectal temperature of rats was dropped into 20+/-1 degrees C during profound hypothermia. Mean arterial blood pressure in both acute and chronic ethanol treatments plus hypothermia significantly dropped into low levels as well as in hypothermia alone (P<0.01). Hypothermia led to a significant increase in the content of EB dye in the brain regions of rats (P<0.05). Both acute and chronic ethanol treatments plus hypothermia did not lead to a significant increase in the BBB permeability against intravenously injected EB dye. We conclude that ethanol intake protects the BBB against the effects of hypothermia.     

Hyperuricemia in rats during acute carbon monoxide poisoning

The effect of carbon monoxide (CO) inhalation on plasma levels of uric acid and hypoxanthine in rats was investigated. Exposure to 3% CO caused respiratory arrest within about 2 minutes. The plasma uric acid level of CO-treated rats increased to 157% above that of ether-treated rats. When rats were exposed to 1% or 0.8% CO, the exposure periods until the onset of respiratory arrest were prolonged, and plasma uric acid levels at respiratory arrest were further elevated. Plasma uric acid levels at respiratory arrest increased with prolongation of the exposure periods. Under our experimental conditions, hypoxanthine or xanthine was not detected in plasma of CO-treated rats. These results are discussed in relation to the hyperuricemia in hemorrhagic shock or hypoxemia: CO-induced hyperuricemia can be attributed to the stimulated degradation of adenine nucleotides under tissue anoxia, and thus could be an excellent parameter of tissue anoxia.     

Dental amalgam and mercury levels in autopsy tissues: food for thought

Eighteen cadavers from routine autopsy casework were subject to a study of tissue levels of total mercury in brain, thyroid, and kidney samples by atomic absorption. On these same cadavers, all dental amalgam fillings (the most important source of inorganic mercury exposure in the general population, according to the World Health Organization (WHO) were charted. Total mercury levels were significantly higher in subjects with a greater number of occlusal amalgam surfaces (>12) compared with those with fewer occlusal amalgams (0-3) in all types of tissue (all P < or = 0.04). Mercury levels were significantly higher in brain tissues compared with thyroid and kidney tissues in subjects with more than 12 occlusal amalgam fillings (all P < or = 0.01) but not in subjects with 3 or less occlusal amalgams (all P > or = 0.07).     

Effect of toluene inhalation on astrocytes and neurotrophic factor in rat brain

Toluene, an abused substance in Japan, is a neurotoxic chemical that has been shown to have neurobehavioral and electrophysiological effects. In previous work, both acute and chronic effects of toluene on cells have been studied extensively. However, although glial cells are thought to play an important role in the survival of neurons in the brain, the effect of toluene on glial cell function has not yet been characterized. To elucidate this, the effect of toluene inhalation on astrocytes in rat brain was examined. Toluene exposure (1500 ppm for 4 h on 4-10 days) augmented glial fibrillary acidic protein (GFAP) immunoreactivity, particularly in the hippocampus and cerebellum. Quantitative analysis showed that toluene inhalation markedly enhanced GFAP expression in the hippocampus and cerebellum. In both regions, proliferating cell nuclear antigen (PCNA) showed no obvious changes, but glutamine synthetase (GS)-immunoreactive cells were markedly increased by toluene exposure. Thus, the elevation of GFAP expression was induced by astrocyte activation rather than by cell proliferation. If toluene exposure activates astrocytes, astrocytes may play a role in the neurophysiological changes observed in toluene intoxication. A neurotrophic factor, basic fibroblast growth factor (b-FGF) was observed immunohistochemically in the capillary vessel walls in the hippocampus and the cerebellum of toluene-intoxicated rats. Basic-FGF may have induced GFAP expression both in the hippocampus and the cerebellum. So, other neurotrophic factors may affect the difference of GFAP elevation between the hippocampus and the cerebellum. These differences may relate to neurobehavioral function of each brain part after toluene exposure.     

MMP-2和MMP-9与脑损伤及其法医学意义

基质金属蛋白酶2和9（MMP-2、MMP-9）是基质金属蛋白酶（matrix metalloproteinases，MMPs）家族中的两个成员，可降解Ⅳ型胶原、层粘连蛋白等基质成分，从而使血脑屏障结构破坏，通透性增加，导致血管源性脑水肿，在脑血管疾病和脑损伤形成过程中起着重要的作用。在损伤后不同时段，MMP-2和MMPO含量及分布均呈现一定的波动性，探讨这些问题对脑损伤的治疗及在法医学中推断脑损伤时间有十分重要的意义。本文就这些问题的相关研究作一概述。     

灌服毒鼠强诱导大鼠细胞DNA的损伤研究

目的研究毒鼠强体内染毒后,毒鼠强对大鼠脑细胞、心肌细胞、淋巴细胞DNA的损伤作用。方法选择健康Sprague-Dawley大白鼠20只,分成5组,每组4只,采用灌胃方法使大鼠毒鼠强体内染毒,按0.2,0.1,0.05,0.01mg·kg-1制作大鼠毒鼠强中毒模型,并以灌服生理盐水的健康大鼠为对照,分离实验大鼠的淋巴细胞、心肌细胞和脑细胞,用彗星电泳的方法测定不同浓度毒鼠强中毒后的细胞DNA损伤。结果0.2,0.1,0.05,0.01mg·kg-1剂量组的毒鼠强均可引起大鼠的淋巴细胞、心肌细胞和脑细胞DNA损伤,均与对照组差异有显著性(P<0.01)。结论毒鼠强诱导体内细胞DNA损伤可能是毒鼠强毒性作用机制之一。     

Alcohol intoxication may exacerbate the effects of blunt cranial trauma through changes in brain free magnesium levels

Moderate to high levels of alcohol decrease brain intracellular free magnesium concentration, a factor known to be critical in brain injury. Phosphorus magnetic resonance spectroscopy was used to examine changes to brain free magnesium concentration after blunt cranial trauma in alcohol-intoxicated rats. Rats exposed acutely or chronically to alcohol sufficient to increase blood alcohol levels to between 150 and 350 mg/dL demonstrated a brain free magnesium level that was 20-50% less than in nonintoxicated animals (p < 0.01). After injury, brain free magnesium levels declined more rapidly and to a greater extent in alcohol-affected animals than in nonintoxicated control animals (p < 0.001). As both preinjury depletion of magnesium and degree of magnesium decline after brain injury have been associated with poor recovery, these findings suggest that moderate to severe alcohol intoxication may predispose the brain to a worse outcome by reducing brain free magnesium levels, both before and after injury.     

海洛因诱导大脑神经元凋亡的研究

目的观察海洛因有无直接诱导培养大脑神经元凋亡的作用。方法神经元培养取自SD大鼠妊娠的胎鼠大脑皮质,培养7d后分别用不同浓度的海洛因(纯度80%)处理大脑神经元24h。用FDA法分析细胞存活率,Hoechst 33258荧光染色后观察凋亡的形态学改变,再用DNA琼脂糖凝胶电泳分析凋亡的生化特征。结果海洛因可剂量依赖性地降低神经元的存活率;荧光显微镜可见细胞核染为高亮蓝色的典型凋亡小体,其细胞核明显固缩、凝聚和断裂,且随海洛因剂量的增加,出现凋亡小体的细胞明显增多;不同浓度的海洛因处理大脑神经元,电泳图谱显示清晰的DNA梯带。结论海洛因可直接诱导大鼠大脑皮质神经元凋亡。     

可卡因对性成熟期雄性大鼠生殖功能的损害

目的探讨可卡因对性成熟期雄性大鼠生殖功能的影响及其作用机制。方法选用性成熟期健康雄性SD大鼠30只，随机分为实验组和对照组，每组15只。实验组大鼠以15mg／kg剂量每天皮下注射可卡因28d。观察动物体质量、睾丸质量改变，检测血液中激素含量的变化．利用原位缺口末端标记（TUNEL）法检测睾丸细胞的凋亡，免疫组化方法检测睾丸Fas基因的表达。结果（1）实验组大鼠体质量、睾丸质量明显低于对照组（P〈0．05）；（2）实验组与对照组相比，睾酮含量明显降低（P〈O．05）：（3）实验组睾丸细胞凋亡较对照组明显增多（P〈0．05），Fas基因表达明显增加（P〈0．05）．且Fas基因阳性表达与睾丸细胞的凋亡指数呈正相关（r=0．9012，P〈O．05）。结论可卡因可致大鼠生殖器官发育和生殖内分泌功能损害．造成生精细胞凋亡．增殖能力下降．可能与Fas介导的睾丸生精细胞凋亡机制有关。     

Human serum paraoxonase (PON1) activity in acute organophosphorous insecticide poisoning

Human serum paraoxonase (PON1) and perhaps other mammalian paraoxonases catalyzes the hydrolysis of certain organophosphorus (OP) insecticides and nerve gases and so may alter significantly an individual's susceptibility to the toxicity of these chemicals. Serum PON1 exhibits a substrate dependent polymorphism and this polymorphism shows great interethnic variability. This study focused on the investigation of PON1, arylesterase and cholinesterase activities in 28 acute OP insecticide poisoning cases. Insecticide analysis were performed by GC-NPD and activities of enzymes were measured by using spectrophotometer. The activity levels for salt stimulated PON1, basal PON1 and arylesterase were found as 78.83 (35.39-186.13), 39.97 (2.49-80.43) micromol/min/l and 126.26 (36.34-288.24) mmol/min/l respectively. On the other hand the activity levels for butyrylcholinesterase (BTC) and acetylcholinesterase (AchE) were found as 797.23 (106.3-3823)U/l and 4.65 (0.21-30.29)U/ml. There was a correlation between percent stimulation of PON1 and BTC activities (r=0.446, P<0.05), but this correlation was lower than in cases who exposed to OP insecticides chronically. As a conclusion, in chronic and acute OP exposure, both PON1 level and phenotype must be taken into consideration.     

Dermal absorption of kerosene components in rats and the influence of its amount and area of exposure

The influences of amount and area of dermal exposure to kerosene upon the levels of kerosene components in biological samples were examined in vivo and in vitro. Thirty-two rats were randomly divided into four groups and exposed to kerosene through the abdominal skin for 2h. The amounts (soaked in cotton) and area of kerosene exposed were 1 ml/4 cm(2) in Group I, 4 ml/4 cm(2) in Group II, 4 ml/16 cm(2) in Group III and 16 ml/64 cm(2) in Group IV. Before, then 5, 10, 20, 30, 45, 60, 90 and 120 min after exposure, 0.5 ml of blood was collected. Solid tissue samples, including the exposed skin area, were harvested at 120 min. Kerosene components were analyzed by gas chromatography/mass spectrometry. Trimethylbenzens (TMBs) that are easily absorbed kerosene components, appeared at 5-20 min. The time course changes in TMB levels in blood were significantly different between Groups I and II or Groups I and III, and almost identical between Groups II and III. Similar trends were observed in tissue samples at 120 min. High concentrations of aliphatic hydrocarbons (AHCs) were detected in the exposed skin and the AHC levels were dependent on the amount of kerosene exposed per unit area. These results suggest that (1) dermal absorption of kerosene occurs soon after dermal exposure started, (2) absorption of TMBs is influenced by the total amount of kerosene rather than area of exposure, and (3) AHCs remaining in the skin at significant levels are influenced by the amount of kerosene per unit area exposed.     

Gender-related differences in the pharmacokinetics of opiates

Previous studies have documented gender-related differences in a number of aspects of the pharmacology of opiates, including their analgesic activity, stimulative properties and generation of physical dependence. The current experiments were carried out with the aim to examine whether male–female differences exist in the blood and brain levels of opiates attained after their intraperitoneal injection to male and female Wistar rats. The tests were performed 5, 15, 45 and 120 min after the animal treatment with seized heroin. Gas chromatography–mass spectrometry (GC–MS) method was developed to quantitatively determine opiate alkaloids in blood and brain regions (known for their high concentration of μ-opiate receptors): cortex, brainstem, amygdala and basal ganglia. Maximal contents of opiates in blood of animals of both genders were found in the second measurement time (15 min), the values measured in the males being significantly higher, which suggests a faster passage of the opiates from blood to brain tissue in female animals. The highest content of opiates in the brain tissue of female animals was measured 15 min and with male animals 45 min after the treatment, which also indicates faster distribution of opiates from blood to brain in the female compared to male rats. The highest proportion of opiates was found in the basal ganglia of the animals of both genders. The obtained results offer the possibility of selecting this part of the brain tissue of both males and females as a representative sample for identifying and assessing contents of opiates.     

实验性大鼠脑震荡后Bcl-2的表达

目的观察实验性大鼠脑震荡后Bcl-2表达的变化规律。方法应用免疫组织化学方法检测大鼠脑震荡后不同时间大脑皮层、脑干和小脑等脑区内Bcl-2表达的变化规律进行研究。结果对照组大鼠未见Bcl-2蛋白的表达。脑震荡组损伤后1h组可在神经细胞内观察到少量Bcl-2蛋白的表达,4d达到高峰,8d和16d,Bcl-2蛋白表达随后逐渐下降。结论Bcl-2的检测可能成为脑震荡的诊断和脑损伤时间推断的一个敏感指标。     

The Forensic Implications of Amphetamine Intoxication in Cases of Inflicted Blunt Craniocerebral Trauma

The effects of D‐amphetamine on outcome after blunt craniocerebral trauma are characterized and the potential legal implications discussed. Traumatic brain injury (TBI) was induced under general anesthesia in adult, male Sprague Dawley rats using the impact acceleration model. At 10 min prior to injury, D‐amphetamine (5 mg/kg) or saline vehicle was administered subcutaneously; animals were subsequently assessed over a 7‐day period post‐trauma for motor outcome using a rotarod device. D‐amphetamine treated animals performed significantly better (p < 0.001; ANOVA) than vehicle treated controls on their motor assessment, suggesting that D‐amphetamine exposure prior to injury either is neuroprotective or enhances motor performance. It is possible, therefore, that an individual who has taken amphetamines may function at a better motor level after head trauma than one who has not been exposed to the drug. Future interpretations of the potential effects of amphetamines on TBI should include this possibility.     

The effect of time of death on extravascular tissue/blood secobarbital concentration ratios in the rat

Extravascular liver/blood and brain/blood ratios were found to be an average of 6% and 1% higher, respectively, in all experiments than total liver/blood and brain/blood ratios. This difference may be informative in establishing true tissue levels. There was a significant time effect (P less than 0.05) with the extravascular liver/blood ratios but not with the extravscular brain/blood ratios. Extravascular liver/blood ratios were slightly higher in phenobarbital-pretreated animals than in non-pretreated animals. Tissue secobarbital levels in pretreated and non-pretreated animals are not different at 1/4 or 1 h, even though pretreated animals received higher doses than non-pretreated animals. Tissue levels are significantly higher (P less than 0.01) in pretreated animals than in non-pretreated animals at 4 h. It is possible that, at this time period, the barbiturate-metabolizing enzymes have become saturated or exhausted.     

大鼠急性脑干损伤神经细胞凋亡和轴突的变化

目的研究急性脑干损伤早期的病理变化,探讨其在急性脑干损伤中的法医学意义。方法采用自由落体造成大鼠急性脑干损伤模型,HE染色常规观察各部位脑组织的显微形态改变之后,用TUNEL末端标记检测神经细胞凋亡,用LSAB染色显示神经丝蛋白(NF)。结果实验动物模型能够较好的模拟法医案例;脑干损伤的大鼠脑组织淤血、水肿、环状出血,脑皮质内神经凋亡细胞数目明显增多(P<0.01);脑干部位神经轴突排列紊乱、肿胀、断裂。结论上述多种病理变化对急性脑干损伤的死后诊断具有一定的意义。     

Liver damage in rats during acute carbon monoxide poisoning

Plasma leucine aminopeptidase (LAP) levels and respiration rates of isolated liver mitochondria were studied in carbon monoxide (CO)-poisoned rats sampled at respiratory arrest. An increase in LAP levels paralleled a decrease in the respiratory control ratio and the $\text{ADP}\text{O}$ ratio. The results suggest that the damage to mitochondria closely correlates with the liver damage in rats during acute CO poisoning.     

Distribution of tetracaine and its metabolite in rabbits after high versus normal spinal anesthesia.

High spinal anesthesia is one cause of sudden death associated with the spinal anesthesia. We did animal experiments to verify high spinal anesthesia by analyzing tetracaine and its metabolite, p-butylaminobenzoic acid in tissue samples. Tetracaine (0.25% in 10% glucose solution) 0.21-0.28 mg/kg was administered to two groups of rabbits to induce high and normal spinal anesthesia. Tetracaine and the metabolite in rabbit tissues were analyzed by gas chromatography-mass spectrometry, as a free base for tetracaine and as tert-butyldimethylsilyl derivative for the metabolite. In the group given high spinal anesthesia, levels of the metabolite in the brain stem were higher than in the cerebrum, cerebellum and whole blood. On the other hand, in the group given normal spinal anesthesia, the opposite results were obtained. Therefore, high spinal anesthesia induced by tetracaine can be diagnosed by comparing the concentrations of metabolite in whole blood, cerebrum, cerebellum and brain stem.     

Distribution of drugs of abuse within specific regions of the human brain

Since concentration of drugs of abuse found in the brain better reflect drug concentration at their site of action, brain specimens are useful in the determination of the role of drugs of abuse in the cause of death. In order to allow for the routine use of brain specimens in this field, a comprehensive database with reliable reference values is needed and should include both post-mortem data for cases where drugs have been taken in therapeutic doses as well as for cases of overdose. In this study, a semi-automated extraction procedure, in combination with gas chromatography/mass spectrometry (GC–MS) using stable isotope internal standards was applied to yield reproducible, quantitative results which could be used to investigate the distribution patterns of drugs of abuse within specific regions of the brain, by analyzing several segments of both medulla oblongata and cerebellum. A homogenous distribution of unconjugated morphine, dihydrocodeine, and benzoylecgonine within the investigated segments of medulla oblongata or cerebellum could be found. However, when these two brain regions from the same case were compared to each other, significantly higher concentrations of unconjugated morphine, dihydrocodeine, and benzoylecgonine were found in the cerebellum than in the medulla oblongata.     

Sulfide concentrations in postmortem mammalian tissues

Postmortem changes in sulfide concentrations in body tissues were examined in autopsied rats exposed to hydrogen sulfide concentrations of 550 to 650 ppm, and in nonexposed rats and humans. Analyses were made by gas chromatography, following an extractive alkylation. Sulfide concentrations in the blood, liver, and kidneys of rats increased in both the exposed and nonexposed groups, depending on the lapse of time after death. On the other hand, the lung, brain, and muscle showed little or no change in sulfide concentration with elapse of time after death. The data obtained from human tissues were almost the same as those for rats, except data for blood, in which no or little increase of sulfide was observed.