Perinatal Methanol Exposure in the Rat II Behavioral Effects in Neonates and Adults

The use of methanol as a component of automobile fuel will increaseperinatal exposures in the general population. Few studies haveaddressed questions concerning neurotoxicity stemming from suchexposures. In the current study, four cohorts of pregnant Long-Evansrats, each cohort consisting of an exposure and a control group,were exposed to 4500 ppm methanol vapor in Rochester-type inhalationchambers for 6 hr daily beginning on Gestation Day 6. Exposurecontinued for both dams and pups through Postnatal Day 21 (PND21) to model gestational and neonatal toxicity in humans. Severalbehavioral procedures were used to assess exposure effects inthe offspring. Male-female littermates were studied wheneverpossible to examine sex differences, with one pair from a litterfor each procedure. Exposure to methanol did not affect sucklinglatency and nipple attachment on PND 5 or performance on anaversive olfactory conditioning procedure on PND 10. Exposureto methanol did alter performances in a motor activity procedure.Methanol-exposed neonates were less active on PND 18, but moreactive on PND 25 than the equivalent control group pups. Twooperant conditioning procedures, not used previously in thiscontext, assayed other littermates as adults. A fixed ratioschedule required the rat to rotate a running wheel a specifiednumber of revolutions to obtain food-pellet reinforcers. Whenthe fixed ratio requirement changed, number of responses (revolutions)per 1-hr session displayed a complex interaction with treatment.Changes in performance over the course of training differedbetween males and females depending on exposure to methanol.Compared to initial baseline performances, methanol-exposedmales showed decreases, and methanol-exposed females increases,in the rate of running. A stochastic spatial discriminationprocedure permitted subjects to respond on any three levers,with the probabilities of food-pellet delivery determined bythe location of the preceding response. A reinforcement matrixdefined the response sequence required to maximize reinforcements.When the matrix was changed, the methanol-exposed subjects respondedless efficiently at asymptotic levels of performance than controls.Across procedures, developmental exposure to 4500 ppm methanolvapor was associated with subtle behavioral changes in bothneonates and adults.     

Disposition of Bismuth in the Rat. I. Red Blood Cell and Plasma Protein Binding

The plasma protein and red blood cell binding profile of bismuth was investigated as a function of bismuth concentration. The binding of bismuth to human serum albumin, bovine serum albumin, and human plasma was also evaluated by ultrafiltration and the data analyzed by nonlinear regression techniques. The binding of bismuth to plasma proteins was nonlinear and decreased as a function of incubation concentration and appeared to be limited by the number of ionized 1-cysteine residues available for binding. In the concentration range studied, bismuth was associated primarily with the red blood cell fraction of whole blood obtained from male Sprague Dawley rats. The data indicated that binding to proteins was of moderate affinity, and in whole blood it was present primarily in the red blood cell compartment.     

Pharmacology of Cell Adhesion Molecules of the Nervous System

Cell adhesion molecules (CAMs) play a pivotal role in the development and maintenance of the nervous system under normal conditions. They also are involved in numerous pathological processes such as inflammation, degenerative disorders, and cancer, making them attractive targets for drug development. The majority of CAMs are signal transducing receptors. CAM-induced intracellular signalling is triggered via homophilic (CAM-CAM) and heterophilic (CAM - other counter-receptors) interactions, which both can be targeted pharmacologically. We here describe the progress in the CAM pharmacology focusing on cadherins and CAMs of the immunoglobulin (Ig) superfamily, such as NCAM and L1. Structural basis of CAM-mediated cell adhesion and CAM-induced signalling are outlined. Different pharmacological approaches to study functions of CAMs are presented including the use of specific antibodies, recombinant proteins, and synthetic peptides. We also discuss how unravelling of the 3D structure of CAMs provides novel pharmacological tools for dissection of CAM-induced signalling pathways and offers therapeutic opportunities for a range of neurological disorders.     

Assessment of Offspring Development and Behavior Following Gestational Exposure to Inhaled Methanol in the Rat

The prospect of widespread human exposure associated with itsuse as an alternative fuel has sparked concern about the toxicpotential of inhaled methanol (MeOH). Previous studies haverevealed congenital malformations in rats following inhaledMeOH (Nelson et al. (1985). Fundam. Appl. Toxicol. 5,727–736)but these studies did not include postnatal behavioral assessment.In the present study, pregnant Long–Evans rats were placedin exposure chambers containing 15,000 ppm MeOH or air for 7hr/day on Gestational Days (GD) 7–19. The total alveolardose of methanol was estimated at about 6.1 g/kg/day, for atotal dose of about 42.7 g/kg for the entire study. Maternalbody weights were recorded daily and blood methanol concentrationswere determined at the end of exposure on GD 7, 10, 14, and18. Following birth (Postnatal Day 0 [PND 0]), a number of testswere performed at various points in development, including:offspring mortality and body wt (PND 1, 3), motor activity (PND13–21, 30, 60), olfactory learning (PND 18), behavioralthermoregulation (PND 20–21), T-maze learning (PND 23–24),acoustic startle response (PND 24, 60), reflex modfficationaudiometry (PND 60), pubertal landmarks (PND 31–56), passiveavoidance (PND 72), and visual-evoked potentials (PND 160).Maternal blood MeOH levels, measured from samples taken within15 mm after removal from the exposure chamber, declined fromabout 3.8 mg/ml on the first day of exposure to 3.1 mg/ml onthe 12th day of exposure. MeOH transiently reduced maternalbody wt (4–7%) on GD 8–10, and offspring BW (5%)on PND 1. No other test revealed significant effects of MeOH.Prenatal exposure to high levels of inhaled MeOH appears tohave little effect on this broad battery of tests beyond PND1 in the rat.     

Effect of Perinatal Lead Exposure on Rat Behaviour in Open-Field and Two-Wky Avoidance Tasks

Abstract: In view of conflicting results in literature concerning lead exposure associated with behavioural alterations, this study investigated behaviour in the open-field and shuttle avoidance, for as well as tissue lead burdens of pre- and post-natally lead-exposed rats. Rats were exposed to the metal from conception to weaning by giving the dams 0.5, 2.0 or 4.0 mM lead acetate in drinking water. This regimen did not affect body weight gain of dams or offspring development and had no effect on cerebral weights nor on haematological parameters of 23-day-old rats. In 1-day-old rats, lead accumulated in the blood but not in the brain, whereas both in 23-day-old rats and in dams lead accumulated in blood, kidney and cerebral cortex. In the open-field, lead-exposed groups showed higher locomotor activity in the test session as compared to controls and did not show any decrease in rearing responses in the test, indicating less habituation. Lead-treated rats subjected to a shuttle avoidance task showed no significant increase in avoidance responses between sessions as compared to control, indicating less retention. Moreover, only the control group presented a significant reduction of the footshock escape latency along testing session, suggesting a lead effect on footshock escape acquisition. In the shuttle box, intertrial crossing responses were not affected by lead treatment. The behavioural alterations occurred in animals with blood lead levels in the range 11-50.6 μg/dl.     

不稳定型心绞痛病人血浆氧化低密度脂蛋白与细胞粘附分子表达的变化

目的 探讨不稳定型心绞痛(UA)病人血浆氧化低密度脂蛋白(OX-LDL)和白细胞CD_(18)表达及血清可溶性细胞间粘附分子-1(sICAM-1)浓度的变化。方法 采用酶联免疫吸附法(ELISA),分别检测了46例健康人和56例UA病人心绞痛发作期和缓解后24h的血浆 OX-LDL浓度、白细胞 CD_(18)表达和sICAM-1浓度。结果 UA病人心绞痛发作期和缓解后24h血浆0X-LDL浓度、白细胞CD_(18)表达及sICAM-1浓度明显增高,与对照组比较差异有显著性(P<0.001,P<0.01)。心绞痛发作时血浆OX-LDL、白细胞 CD_(18)表达和sICAM-1浓度均明显高于心绞痛缓解后24h(P<0.001),且发作时和缓解后24h血浆OX-LDL与白细胞CD_(18)表达、sICAM-1之间呈正相关(P<0.001)。自发型心绞痛病人各指标增高较心肌梗死后型和劳力型心绞痛更明显(P<0.01)。结论 血浆OX-LDL和白细胞CD_(18)表达及sICAM-1浓度增高可能与UA的发病和病情变化有密切关系。     

冰片对川芎嗪血药浓度和在脑中分布的影响

目的：探讨冰片对川芎嗪血药浓度和在脑中分布的影响。方法：经股静脉单用或复合冰片给予大鼠川芎嗪10mg／kg，采用高效液相色谱法测定不同时间的血浆和脑组织中川芎嗪药物浓度。结果：川芎嗪复合冰片后，血浆药物浓度发生明显变化，在所观察的时间里，血浆药物浓度比单用川芎嗪低；但川芎嗪复合冰片后能提高川芎嗪在脑组织中的含量。结论：冰片可促进川芎嗪在脑中的分布，川芎嗪复合冰片治疗脑血管疾病时临床显效可能更快。     

Toxicokinetics of Intravenous Methanol in the Female Rat

The toxicokinetics of intravenously administered methanol wereexamined in female Sprague-Dawley rats. Animals received a singleadministration of 100, 500, or 2500 mg methanol/kg; the twolower doses were administered as a bolus, while the high dosewas administered over 1.5 min. A small (approximately 3%) butstatistically insignificant (p>0.1) degree of transpulmonarymethanol extraction, expressed as the fractional arterial-venousdifference in concentration, was observed after administrationof 250 mg methanol/kg. The elimination of methanol from thesystemic circulation was markedly nonlinear, suggestive of asignificant capacity-limited route of elimination. A singleset of kinetic parameters (apparent distributional volume ofthe central compartment [V_c], intercompartmental transfer rateconstants [k₁₂ and k₂₁], and V_max and K_m for elimination) describedthe blood methanol concentration-time data from rats receivingthe 100 and 500 mg/kg doses. Blood methanol concentrations declinedmuch more rapidly in animals receiving the 2500 mg/kg dose thanwould be predicted from the kinetic parameters derived fromthe other two experimental groups. The data from the 2500 mg/kggroup could be described adequately by a kinetic model incorporatingparallel first-order and saturable elimination processes. Aportion of this apparent linear elimination pathway was dueto renal excretion of the unchanged alcohol. The presence ofboth linear and nonlinear elimination pathways for methanolmay have implications regarding high-dose to low-dose toxicologicextrapolations.     

Blood Polyamines in the Rat

The physiological concentrations of polyamines in plasma, serum and red blood cells were determined in male Wistar rats, using HPLC with fluorometric detection. The analysis of the metabolic ratio between polyamines and the frontal cortex/plasma relationship for putrescine, spermidine and spermine, suggest the existence of common mechanisms in the regulation of spermidine in blood and brain.     

Comparative Toxicokinetics of Methanol in the Female Mouse and Rat

The toxicokinetics of methanol in female CD-1 mice and Sprague-Dawleyrats were examined to explore the possibility of species differencesin the disposition of the compound. Mice received a single doseof 2.5 g/kg methanol either po (by gavage) or iv (as a 1-mminfusion). Rats received a single oral dose of 2.5 g/kg methanol.As expected, the disposition of methanol was nonlinear in bothspecies. Data obtained after iv administration of methanol tomice were well described by a one-compartment model with Michaelis-Mentenelimination. Blood methanol concentration-time data after oraladministration could be described by a one compartment (mice)or two-compartment (rats) model with Michaelis-Menten eliminationfrom the central compartment and biphasic absorption from thegastrointestinal tract Kinetic parameters (V_max for elimination,apparent volume of the central compartment [V_e first-order rateconstants for intercompartmental transfer [k₁₂ and k₂₁ and first-orderabsorption rate constants for fast [k_AF] and slow [k_AS] absorptionprocesses) were compared between species. When normalized forbody weight, mice evidenced a higher maximal elimination ratethan rats (V_max=117±3 mg/hr/kg vs 60.7±1.4 mg/hr/kgfor rats). The contribution of the fast absorption process tooverall methanol absorption also was larger in the mouse thanin the rat.     

Chronic Marijuana Smoke Exposure in the Rhesus Monkey I. Plasma Cannabinoid and Blood Carboxyhemoglobin Concentrations and Clinical Chemistry Parameters

Chronic Marijuana Smoke Exposure in the Rhesus Monkey I. PlasmaCannabinoid and Blood Carbxyhemoglobin Concentrations and ClinicalChemistry Parameters SLIKKER, W., JR., PAULE, M. G., ALI, S.F., SCALLET, A. C., AND BAILEY, J. R (1991). Fundam. Appl Toxicol17, 321–334. This report is the first in a series abouta large multidisciplinary study designed to determine whetherchronic marijuana (MJ) smoke exposure results in residual behavioraland/or neuropathological alterations in the rhesus monkey. Priorto the initiation of a year of chronic MJ smoke exposure, 64periadolescent male rhesus monkeys were trained for 1 year toperform five operant behavioral tasks and then divided, accordingto their performance in these tasks, into four exposure groups(n=15–16/group): (1) a high dose (HI) group, exposed 7days/week to the smoke of one standard MJ cigarette; (2) a lowd m (LO) group, exposed on weekend days only to the smoke ofa standard MJ cigarate; (3) an extracted MJ cigarette (EX) group,exposed 7 days/week to the smoke of one ethanol-extracted MJcigarette; and (4) a sham group (SH), exposed 7 days/week tosham exposure conditions. Daily exposures for 1 year were accomplishedusing a mask that covered the subjects' nose and mouth. Averagebody weights (initially 3.7?0.5 kg, mean?SD) and rates of weightgain (approximately 0.1 kg/month) were the same for all groupsthroughout the entire experiment. During the first week of expsure,plasma concentrations of -9-tetrahydrocannabinol and 11-nor-9-carboxy-THCin the HI group were 59?7 (mean?SE) and 5.5?1.5 ng/ml, respectively,45 min after MJ smoke administration and did not change significantlyat similar times after exposure throughout the remainder ofthe year. Whole blood carboxyhemoglobin levels increased toapproximately 13% 1 min after expsure to smoke in either theMJ or the EX groups. Comparison of blood chemistry and hematologyvalues before, during, and after exposure indicated no differencesfor most parameters. During exposure, lymphocytes, alkalinephosphatase and -glutamyl transferase were depressed in theHI group compared to in the SH group. During exposure, aspartateaminotransferase was elevatd for both the HI and EX groups,suggesting a general effect of smoke exposure. Because theseeffects were transient and remained within the range of reportednormal values, these data indicate that long-term, experimentalexperimental exposure to MJ smoke is feasible and does not compromisethe general health of the rhesus monkey.     

成年大鼠嗅球神经干细胞的培养和鉴定

目的建立成年大鼠嗅球神经干细胞分离培养和鉴定方法,探索新的成年神经干细胞种子来源。方法用无血清方法分离培养成年大鼠嗅球来源的神经干细胞;用克隆培养、BrdU整合的方法检验培养细胞的干细胞特性;用免疫荧光细胞化学的方法检测BrdU、神经干细胞标记物Nestin和SOX2,分化的细胞标记物Tuj1、GFAP、NG2的表达。结果从成年大鼠嗅球能够分离、培养出具有自我更新、增殖的神经球,构成神经球的细胞呈Nestin和SOX2阳性,它们分化后产生Tuj1阳性的神经元、GFAP阳性的星形胶质细胞、NG2阳性的少突胶质细胞。结论成年大鼠嗅球存在神经干细胞,能够在体外进行培养、增殖、分化,是神经干细胞的新的种子来源。     

The Effects of Perinatal/Juvenile Methoxychlor Exposure on Adult Rat Nervous, Immune, and Reproductive System Function

In order to address data gaps identified by the NAS report Pesticidesin the Diets of Infants and Children, a study was performedusing methoxychlor (MXC). Female rats were gavaged with MIXCat 0, 5, 50, or 150 mg/kg/day for the week before and the weekafter birth, whereupon the pups were directly dosed with MXCfrom postnatal day (pnd) 7. Some dams were killed pnd7 and milkand plasma were assayed for MXC and metabolites. For one cohortof juveniles, treatment stopped at pnd2l; a modified functionalobservational battery was used to assess neurobehavioral changes.Other cohorts of juveniles were dosed until pnd42 and evaluatedfor changes to the immune system and for reproductive toxicity.Dose-dependent amounts of MXC and metabolites were present inmilk and plasma of dams and pups. The high dose of MXC reducedlitter size by 17%. Ano-genital distance was unchanged, althoughvaginal opening was accelerated in all treated groups, and maleprepuce separation was delayed at the middle and high dosesby 8 and 34 days, respectively. In the neurobehavioral evaluation,high-dose males were more excitable, but other changes wereinconsistent and insubstantial. A decrease in the antibody plaque-formingcell response was seen in males only. Adult estrous cycicitywas disrupted at 50 and 150MXC, doses which also showed reducedrates of pregnancy and delivery. Uterine weights (correctedfor pregnancy) were reduced in all treated pregnant females.High-dose males impregnated fewer untreated females; epididymalsperm count and testis weight were reduced at the high, or toptwo, doses, respectively. All groups of treated females showeduterine dysplasias and less mammary alveolar development; estrouslevels of follicle stimulating hormone were lower in all treatedgroups, and estrus progesterone levels were lower at 50 and150 MXC, attributed to fewer corpora lutea secondary to ovulationdefects. These data collectively show that the primary adulteffects of early exposure to MXC are reproductive, show that5 mg/kg/day is not a NO(A)EL in rats with this exposure paradigm(based on changes in day of vaginal opening, pubertal ovaryweights, adult uterine and seminal vesicle weights, and femalehormone data) and imply that the sites of action are both centraland peripheral.     

Controlled Cell Death by Magnetic Hyperthermia: Effects of Exposure Time,Field Amplitude,and Nanoparticle Concentration

Purpose  

To investigate the effects of alternating magnetic fields (AMF) on the death rate of dendritic cells (DCs) loaded with magnetic nanoparticles (MNPs) as heating agents. AMF exposure time and amplitude as well as the MNPs concentration were screened to assess the best conditions for a controlled field-induced cell death.     

Opioid Disposition and Effects During Chronic Exposure in the Perinatal Period in Man

The effects of opioids on the human reproductive system and on prenatal and postnatal development are very difficult to assess in studies in aniamals and in man for several major reasons. A specific problem encountered when animal models are used to delineate opioid effects in the perinatal period is that the phamacokinetic properties of most opioids are profoundly different in animals than in man. Ethical constraints usually preclude the administration of any narcotic to humans solely for research purposes and clearly, opioids may not be administered on a chronic basis for purposes of clinical investigation. Thus, there are limited human models for study of the effects of opioids on reproductive function and in the perinatal period. Any study carried out on a population of heroin addicts is confounded by the fact that the amounts and frequency of heroin self-administration remain obscure, and extent of polydrug an dalcohol abuse unkown. Although methadone-maintained patients provide a more controlled group of potential subjects for research, like the street heroin addict (and the general population), 20-50% fo these patients use or abuse other drugs or alcohol in excess. Only limited number of alternations in normatl physiology have been documented in infants who have been exposed to methadone in utero without, and in some cases even with, significant concomitant exposure to other drugs or alcohol. Of the perinatal effects, the most commonly described problem is the syndrome of neonatal narcotic withdrawal, which usualy has its onset between the 24th and 48th hours after birth. A more subtle, but possibly very common, problem is that of relative fetal abstinence in utero, which is probably characterized by hypoxia, hyperactivity and, in some cases, results in fetal death. A few specific effects of chronic methadone exposure in the perinatal period have been delineated; one of these, the observed effects on respiratory physiology, may be direct narcotic effect; another one, thrombocytosis, may be due to indirect effects or due to effects of narcotic withdrawal. Many other more subtle physiological, biochemical, psychological and developmental perturbations due to chronic methadone wxposure or exposure to other long-acting or short-acting narcotics, or endogenous opioids which are present in elevated levels in the perinatal period may be documented in the future, as a result of more precise and detailed observations made as part of carefully controlled prospective studies, in both narcotic dependent and otherwise healthy unmedicated pregnant human females. The development of more appropriate animal models than are currently available, which could be used to delineate the mechanisms of any alterations observed in teh perinatal period in man, would also greatly facilitate the expansion of knowledge in this important area.     

全血细胞分析中不同浓度的EDTA-K_3对红细胞体积的影响

为研究全血细胞分析中不同浓度的乙二胺四乙酸三钾 (EDTA-K3)对红细胞体积的影响 ,抽取健康受检者静脉血分别注入不同浓度的 EDTA-K3 溶液 6组各组小管中 ,每小管 10 0 ul,使各小管中 EDTA-K3 的浓度分别为 1.6、1.8、2 .0、2 .2、2 .4、2 .6 mg/ml。测定未凝血组小管中的平均红细胞体积 (MCV)和红细胞压积 (Hct) ,并对其数据进行 t检验。结果显示 ,1.8～ 2 .0 mg/ml的 EDTA-K3用于全血细胞分析对红细胞体积影响最小     

反相高效液相色谱法测定红细胞中6—巯嘌呤代谢产物的浓度

目的 :研究急淋白血病患儿红细胞内 6 -MP 3种代谢产物的含量情况。方法 :应用反相高效液相色谱技术 ,采用外标法 ,样品经乙酸苯汞加合物提取 ,色谱柱为DupondC18(10 μm ,4 6mm× 2 5 0mm) ,柱温 15℃～ 2 0℃ ,流动相为甲醇 -水 (5∶95 ) ,流速 0 9mL·min-1,检测波长 330和 30 0nm。结果 :红细胞内 6 -TGN、 6 -TIMP、 6 -MeMP的浓度在 5～ 2 0 0 0ng/ 8× 10 8红细胞范围内线性关系良好 ,rs=0 885 5～ 0 9871,天内RSD为0 2 %～ 1 2 % ,天间RSD为 1 1%～ 2 1%。结论 :本方法简便、快速、准确 ,适用于 6 -MP细胞内药理学研究     

HSCT患儿血浆中白消安的浓度测定及暴露量研究

目的:建立测定造血干细胞移植(HSCT)患儿体内白消安(BU)血药浓度的液相色谱-串联质谱(LC-MS/MS)法,并进一步估算非清髓预处理(RIC)方案下患儿体内BU暴露情况.方法:以白消安D8(BU-D8)为内标,乙腈蛋白沉淀,色谱柱为Waters ACQUITY UPLC BEHC18(50 mm×2.1 mm,1.7μm);柱温:40℃;流动相以含0.1％甲酸的乙腈为有机相,以含10 mmol·L-1甲酸铵和0.1％甲酸的水溶液为水相,梯度洗脱;流速:0.4 mL·min-1;进样量:2μL.采用电喷雾离子源(ESI)和多反应监测(MRM)模式检测,BU和BU-D8离子通道分别为m/z 264.10→150.90和m/z 272.10→159.10.使用NextDose贝叶斯回归模型分别计算患儿体内BU暴露量,以药-时曲线下面积(AUC)表示.结果:BU在0.1～10.0μg·mL-1范围内具有良好的线性关系,定量下限为0.1μg·mL-1.定量下限以及低、中、高浓度质控品的批内和批间精密度分别为4.3％～5.1％和3.2％～6.9％,平均提取回收率为(111.2±11.8)％,经内标归一化的基质效应均<15％.21例患儿经模型估算的BU AUC中位值为1191.23(775～2511.57)μmol·min·L-1),个体间差异较大.结论:该方法灵敏度、准确度高,操作简便快速,适用于临床开展BU血药浓度监测.RIC方案下患儿体内BU暴露存在个体差异性,有待进一步开展相关研究.