Comparison of blood toluene levels after inhalation and oral administration

The purpose of this investigation was to compare blood toluene levels in Sprague-Dawley rats after oral and inhalation administration. Groups of 30 rats were dosed by gavage with 86.7, 217, 433, or 867 mg toluene/kg body wt or exposed for up to 6 hr, 5 rats per exposure, to an atmosphere of either 200 or 1000 ppm toluene. Blood was sampled by cardiac puncture from 5 rats in each of the six dose groups at 0.5, 1.0, 2.0, 4.0, 6.0, and 24.0 hr after gavage dosing or the beginning of the inhalation exposure. Blood toluene levels were analyzed. A four-parameter model was fitted to the blood toluene levels of the orally dosed rats. The area under the curve generated by this model, representing total blood toluene concentration over 6 hr, was calculated and compared to the area under the blood toluene curve for the 6-hr inhalation exposure. Integrated areas from the two routes of exposure were used for direct comparison of oral and inhalation exposures. The data demonstrate that gavage dosing can be used to approximate inhalation exposure to toluene.     

Hygienic evaluation of the combined effect of portable water chloroform

The paper considers the significance of complex entrance of chloroform from portable water into the human body (enterally, inhalationally, and through the intact skin). It shows it necessary to toughen the maximum permissible concentration (MPC) of chloroform in the portable drinking, by taking into account of the multiplicity of routes of its action on the population. The authors present the results of their own investigations of the levels of chloroform in the air of bath and shower rooms before and after taking a shower and filling the bath with water, as well as in the airspace layer above the water of an indoor swimming pool, by using chromatographic mass-spectrometry.     

Neuroprotective effect of oral choline administration after global brain ischemia in rats

Abstract

Choline – now recognized as an essential nutrient – is the most common polar group found in the outer leaflet of the plasma membrane bilayer. Brain ischemia-reperfusion causes lipid peroxidation triggering multiple cell death pathways involving necrosis and apoptosis. Membrane breakdown is, therefore, a major pathophysiologic event in brain ischemia. The ability to achieve membrane repair is a critical step for survival of ischemic neurons following reperfusion injury. The availability of choline is a rate-limiting factor in phospholipid synthesis and, therefore, may be important for timely membrane repair and cell survival. This work aimed at verifying the effects of 7-day oral administration with different doses of choline on survival of CA1 hippocampal neurons following transient global forebrain ischemia in rats. The administration of 400 mg/kg/day divided into two daily doses for 7 consecutive days significantly improved CA1 pyramidal cell survival, indicating that the local availability of this essential nutrient may limit postischemic neuronal survival.     

沙美特罗替卡松吸入联合顺尔宁口服治疗儿童哮喘疗效分析

目的:探讨沙美特罗替卡松吸入联合孟鲁斯特纳(顺尔宁)口服治疗儿童哮喘的治疗效果。方法:将85例支气管哮喘患儿随机分为观察组和对照组,在常规治疗的基础上,观察组患者应用沙美特罗替卡松粉吸入剂及顺尔宁,对照组患者应用沙美特罗替卡松粉吸入剂,治疗周期均为3个月。比较两组患儿治疗前后哮喘症状评分的变化及治疗前后肺功能的变化。结果:治疗后,两组患者日间及夜间哮喘症状评分均显著改善,且观察组患者改善更加明显(P<0.05)。治疗后,观察组患者MVV、VC、FVC及FEV1改善均显著优于对照组(P<0.05)。治疗后2～7天,观察组患者PEF变异率均显著优于对照组(P<0.05)。结论:沙美特罗替卡松吸入联合顺尔宁口服治疗儿童哮喘能够明显改善患儿症状及肺功能,具有很高的应用价值。     

Absorption and excretion of the 8-hydroxydaidzein in rats after oral administration and its antioxidant effect

8-Hydroxydaidzein (8-OHD), which is produced during the processing of fermented soybean products, has a potent antioxidant activity in vitro. There is no information regarding the absorption and excretion of this isoflavone, including its antioxidant effect in vivo. In this study, rats were administered a single oral dose of 8-OHD (20 mg/kg body weight), and the blood, liver, kidney and urine were collected at specific intervals up to 18 h after dosing. Free 8-OHD in each tissue was directly determined by using HPLC with electrochemical detection, while its conjugates were detected after the treatment with beta-glucuronidase and sulfatase. The total 8-OHD in liver reached a high level (9.4 nmol/g) at 1 h after dosing, and maintained the relatively high concentration up to 10 h. Most of the 8-OHD was present in free form in liver, while the majority of 8-OHD in plasma was conjugated. This suggests that free 8-OHD in liver is successively converted to glucuronide and/or sulfate and the conjugated 8-OHD is released into the blood. The maximum level of total 8-OHD in plasma or kidney was observed within the first 2 h after the oral administration. The level of 8-OHD in these tissues gradually decreased within the further experiments. Excretion of the 8-OHD in urine began to rise at 1-2 h interval. The mean urinary excretion rate of 8-OHD showed a higher level at 2-4 h and 4-6 h intervals, while the 8-OHD levels at these intervals in plasma or kidney more rapidly decreased. The cumulative recovery of 8-OHD in the urine over the 0-18 h interval was about 36% of the dose. In addition, the liver homogenate from rats killed at 1 h and 2 h after dosing, which contained a higher level of free 8-OHD, showed a significantly lower susceptibility to lipid peroxidation induced by AAPH or Cu2+ than that at 0 h (pre-administered rats). These results suggest that 8-OHD was relatively easily absorbed into rats and might exert its biological activities in vivo, including the antioxidant effect.     

Hygienic evaluation of the effect of petroleum hydrocarbons on the soils of megapolises

The paper gives the results of studying the quantity of petroleum hydrocarbons in the Moscow soil, as well as the latter's hygienic evaluation by the changes in acidity (pH) and redox potential and by the sanitary state (the levels of Escherichia coli and viable helminthic eggs). The study has ascertained that the petroleum-polluted soils show changes in medium pH and redox conditions that determine the biological activity of the substances and the trend in their disintegration processes and revealed a relationship of thy sanitary state of Moscow soils to their level of petroleum hydrocarbons.     

Plasma levels of d-norgestrel after oral administration

Peripheral plasma levels of d-norgestrel were determined by radioimmunoassay in five women after oral administration of 30, 250 and 1000 μg d-norgestrel. Peak levels of d-norgestrel in plasma were mostly seen within 2 hours after intake of the pills. The peak concentrations found were 0.9–2.0 ng/ml, 3.3–5.1 ng/ml and 14.0–23 ng/ml, respectively, for the three doses administered. The plasma concentrations of d-norgestrel 24 hours after ingestion of the pills were 0.05–0.14 ng/ml, 0.3–0.7 ng/ml and 1.8–5.2 ng/ml, respectively.The plasma half-life of d-norgestrel for the period 8–24 hours following the tablet intake was around 13 hours but varied considerably among the participants. For the period 24–72 hours the corresponding half-life was around 21 hours.During 3 weeks treatment with combined oral contraceptives containing d-norgestrel and ethinyl estradiol, increasing d-norgestrel levels in plasma were found in most of the subjects. Patients on low dose gestagen pills (30 μg d-norgestrel) showed constant plasma levels of d-norgestrel throughout a treatment period of 3 weeks.The results obtained in this study suggest that the gradual increase of the d-norgestrel levels found in plasma when d-norgestrel is given in combination with ethinyl estradiol might be due to increased levels of sex hormone binding globulin, the carrier protein for d-norgestrel, rather than to accumulation caused by a long biological half-life.     

Hygienic evaluation of the combined effect of electromagnetic fields and pesticides in experimental conditions

The paper deals with the evaluation of combined effects of some natural and anthropogenic factors that are typical of the Kursk magnetic anomaly region by means of dispersion analysis in the experiments on albino rats and mice. The resultant signs were the indices of animal deaths, nonspecific protective factors, immune responses, changes in body weight, etc. A higher geomagnetic field can modify the biological effects of exposure to agricultural chemicals. The combined effects of a static electromagnetic field with induction of 300 microT to 0.3 T and of chlorpyrifos at various concentrations (0.1, 1, 50, and 100 mg/kg) were found to potentiate the toxic properties of the pesticide. The proportion of the potentiation effects increased as the intensity of the studied factors rose. The dispersion analysis established a predominant role of chlorpyrifos in the combined effects of the factors on the death of animals, serum complementary activity, antibody- and rosette-forming cells of the spleen and other lymphoid organs. The role of a static electromagnetic field is prevalent in the formation of effects of the intensity and completeness of phagocytosis.     

护理干预对预防脑卒中后口腔感染的效果评价

目的探讨早期护理干预对预防脑卒中后口腔感染的效果。方法选择2009年10月-2010年3月笔者所在科脑卒中患者104例,随机分为对照组和观察组,各52例,对照组不给于口腔护理,观察组实施口腔护理,有针对性的给予早期护理干预。比较两组口腔感染的情况。结果观察组的口腔感染发生率明显低于对照组。结论通过早期有针对性的护理干预,可以有效预防脑卒中患者LI腔感染。