Diesel engine exhaust exposure in underground mines: Comparison between different surrogates of particulate exposure

Exposure to diesel particulate matter (DPM) is frequently assessed by measuring indicators of carbon speciation, but these measurements may be affected by organic carbon (OC) interference. Furthermore, there are still questions regarding the reliability of direct-reading instruments (DRI) for measuring DPM, since these instruments are not specific and may be interfered by other aerosol sources. This study aimed to assess DPM exposure in 2 underground mines by filter-based methods and DRI and to assess the relationship between the measures of elemental carbon (EC) and the DRI to verify the association of these instruments to DPM. Filter-based methods of respirable combustible dust (RCD), EC, and total carbon (TC) were used to measure levels of personal and ambient DPM. For ambient measurements, DRI were used to monitor particle number concentration (PNC; PTrak), particle mass concentration (DustTrak DRX and DustTrak 8520), and the submicron fraction of EC (EC_1;Airtec). The association between ambient EC and the DRI was assessed by Spearman correlation. Geometric mean concentrations of RCD, respirable TC (TC_R) and respirable elemental EC (EC_R) were 170 µg/m³, 148 µg/m³, and 83 µg/m³ for personal samples, and 197 µg/m³, 151 µg/m³, and 100 µg/m³ for ambient samples. Personal measurements had higher TC_R:EC_R ratios compared to ambient samples (1.8 vs. 1.50) and weaker association between EC_R and TC_R. Among the DRI, the measures of EC₁ by the Airtec (ρ = 0.86; P < 0.001) and the respirable particles by the DustTrak 8520 (ρ = 0.74; P < 0.001) showed the strongest association with EC, while PNC showed a weak and non-significant association with EC. In conclusion, this study provided important information about the concentrations of DPM in underground mines by measuring several indicators using filter-based methods and DRI. Among the DRI, the Airtec proved to be a good tool for estimating EC concentrations and, although the DustTrak showed good association with EC, interferences from other aerosol sources should be considered when using this instrument to assess DPM.     

Antenatal presentation of biliary atresia

OBJECTIVES: To investigate the incidence, presence of associated anomalies, type of malformation, and natural history of children with biliary atresia (BA) who presented antenatally.Study design The database of 194 infants diagnosed with BA at our tertiary referral unit between 1991 and 2002 was reviewed for infants in whom routine antenatal ultrasound had revealed biliary cystic malformations (BCMs). A retrospective analysis of their medical records was undertaken. RESULTS: Nine infants (six girls) with BCM were identified (4.6% of total referred patients with BA); all were born after 37 weeks' gestational age and presented to us at a median age of 4 weeks (range, 1-14 weeks). The presence of the BCM was confirmed on postnatal ultrasonography. Median age at corrective surgery was 5 weeks (range, 2-16 weeks). At surgery, six patients had type III BA, including one with the biliary atresia-splenic malformation syndrome; two had type II BA; and one had type I BA. Postoperatively, the infants were followed for a median of 2 years (range, 6 months to 11 years). All infants successfully cleared their jaundice. CONCLUSIONS: Improved techniques in routine antenatal ultrasonography can allow early recognition of BCM. This study suggests that BCM noted antenatally may represent early presentation of both biliary atresia-splenic malformation and nonsyndromic BA.     

朱砂莲提取物(A_(1015))对D-氨基半乳糖胺肝损伤模型小鼠DNA合成作用的影响

目的　研究朱砂莲提取物 (A10 15)对D 氨基半乳糖胺(D Gl)肝损伤模型小鼠DNA合成作用的影响。方法　采用D Gl造模 ,3 H TdR参入法测定小鼠肝细胞DNA合成 ,并与肝细胞再生因子进行比较。观察了A10 15的剂量曲线和时间曲线。结果和结论　朱砂莲提取物 (A10 15)抵抗D Gl造成的肝组织坏死和促进肝脏细胞DNA合成作用的最适剂量为 2 5mg·kg-1体重。试验还提示A10 15的抗肝中毒作用2 0 0 1-12 -2 6收稿 ,2 0 0 2 -0 3 -0 6修回1 华西医科大学基础部药理学教研室 ,成都　 610 0 41作者简介 :刘碧崇 ,女 ,3 7岁 ,副研究员 ,博士。研究方向 :微生物药物与中药研究。Tel:0 2 8 43 780 40 ,Fax :0 2 8 43 3 3 2 18,E mail:huanggen @mail sc cninfo net;王浴生 ,男 ,81岁 ,教授 ,博士生导师。研究方向 :抗生素与中药药理不强于肝细胞再生因子     

Effect of nerve extract on number of acetylcholine receptors in denervated muscles of rats

We have shown elsewhere that injection of an extract of peripheral nerves reduces the atrophy of denervated muscle fibers in vivo. Denervated muscle fibers exhibit supersensitivity to acetylcholine owing to the production of extrajunctional acetylcholine receptors. We sought to determine whether or not injection of nerve extract can influence the numbers of acetylcholine receptors in normal, immobilized, or denervated extensor digitorum longus muscles of rats. The receptors were assayed by measuring the binding of ¹²⁵I-α-bungarotoxin. Normally innervated muscles injected with nerve extract exhibited slightly increased binding of the toxin, but this was due to the injections per se. Immobilization caused a small, transient increase in binding of α-bungarotoxin, whereas denervated muscles bound considerably more toxin than innervated controls. The nerve extract did not reduce or prevent the increase in acetylcholine receptors caused by denervation but instead caused an even greater increase. We concluded that the neurotrophic factor extracted from peripheral nerve that is responsible for the maintenance of the sizes of the fibers probably does not down-regulate extrajunctional acetylcholine receptors. The limitation of acetylcholine receptors to the end-plate regions is probably effected by a different mechanism which has yet to be elucidated.     

In vivo [14C]amino acid profiles in discrete hypothalamic regions during push-pull perfusion in the unrestrained rat.

In the unanesthetized rat, the differential release of [¹⁴C]amino acids into a perfusate from a push-pull cannula was analyzed for 20 circumscribed areas of the hypothalamus. To serve as an exogenous precursor for [¹⁴C]amino acid synthesis. [U-¹⁴C]glucose was injected in a vol of 0.5–1.0 μl into a discrete hypothalamic region 20 min prior to a push-pull perfusion. Then, at 15min intervals, the labeled site was perfused for 5 min with an artificial cerebrospinal fluid usually at a rate of 10μl per min. Each sample of perfusate was extracted and assayed by two-dimensional, thin-layer chromatography for the presence of eight amino acids and residual glucose.The pattern of recovery of ¹⁴C-labeled substances as well as the distribution of ¹⁴C between γ-aminobutyric acid, glutamate, aspartate, alanine, taurine and glycine depended solely upon the neuroanatomical region perfused. Near the lateral edge of the ventromedial nucleus, 67% of the amino acid activity was accounted for by [¹⁴C]GABA. Perfusion sites medial to or within this nucleus, or others near the anterior hypothalamus or paraventricular nucleus, yielded a recovery of labeled GABA that was equal to that of glutamate, together accounting for two-thirds of the total ¹⁴C recovery. Within many perfusion loci, small amounts of [¹⁴C]alanine and [¹⁴C]aspartate were detected, whereas within most sites the respective recovery of [¹⁴C]aspartate, [¹⁴C]alanine, [¹⁴C]taurine and [¹⁴C]glycine was negligible. Finally, the metabolism of [¹⁴C]amino acids in the rat's hypothalamus decreased exponentially over time with little identifiable content obtained 80 min following injection of the glucose precursor.These results demonstrate that putative amino acid transmitters can be recovered from the brain of a freely moving animal, and can be characterized in vivo within specific neuroanatomical regions.     

甲状旁腺激素对人牙乳头间充质细胞DNA合成、细胞周期和超微结构的影响

目的：观察和分析体外培养的人牙乳头间充质细胞经甲状旁腺激素（ｐａｒａｔｈｙｒｏｉｄ ｈｏｒｍｏｎｅ,ＰＴＨ） 作用后,ＤＮＡ合成、细胞周期和超微结构的变化情况,探讨ＰＴＨ 对人牙乳头间充质细胞生长和分化的生物学特性的影响。方法：流式细胞仪（ＦＣＭ） 分析、３Ｈ－ ＴｄＲ 掺入试验和透射电镜（ＴＥＭ） 观察。结果：ＰＴＨ 不影响体外培养的人牙乳头间充质细胞ＤＮＡ合成和细胞增殖;ＰＴＨ 能促进人牙乳头间充质细胞向分化成熟、功能活跃的方向发展,且有浓度依赖性。结论：ＰＴＨ 可能不影响体外培养的人牙乳头间充质细胞增殖,而仅促进细胞的分化和功能活跃。     

甲状旁腺激素对培养的人牙乳头间充质细胞环磷酸腺苷含量的影响

目的：观察甲状旁腺激素（Ｐａｒｃｉｔｈｙｒｏｉｄ ｈｏｒｍｏｎｅ,ＰＴＨ） 对人牙乳头间充质细胞内外碱性磷酸酶活性的影响。方法：酶动力学方法。结果：在观察期间（３ ～７ｄ） ,ＰＴＨ 使人牙乳头间充质细胞内ＡＬＰ活性降低,而使细胞外ＡＬＰ活性增加,且有浓度依赖性。ＤＢｃＡＭＰ组可模拟ＰＴＨ 组的结果;ＰＴＨ＋ ＩＢＭＸ 组ＡＬＰ活性的变化大于单纯的ＰＴＨ 组,提示：ＰＴＨ 的作用通过细胞内ｃＡＭＰ介导。结论：ＰＴＨ 可能是成牙本质细胞分化的重要介质。     

Ethnopharmacological study of plants from Pondoland used against diarrhoea

Ethnopharmacological relevance

Waterborne diseases such as diarrhoea are common world wide, including in Bizana, South Africa where the majority of rural dwellers depend largely on water from unprotected sources. The people from Bizana use medicinal plants as their first line of health care to cure and prevent diarrhoea.

Aim of the study

To record and document plants used for the treatment of diarrhoea in Bizana, to evaluate antibacterial and anti-inflammatory activities of selected plant extracts as well as to perform genotoxicity testing of evaluated plants.

Materials and methods

An ethnobotanical approach was used to select plants used for treating diarrhoea in Bizana for pharmacological assays using questionnaires. Nine plants were selected for bioassays based on their frequency index and the fact that they have never been evaluated against diarrhoea causing-microorganisms. The petroleum ether (PE), dichloromethane (DCM), 70% ethanol (EtOH), and water extracts were evaluated for antibacterial (Gram-positive Staphylococcus aureus, Gram-negative Escherichia coli and Shigella flexneri) activity using the microdilution technique, their ability to inhibit COX-1 and COX-2 enzymes. Genotoxicity was evaluated using the Salmonella microsome assay.

Results

This study revealed that 34 plant species belonging to 27 families are used for the treatment of diarrhoea in Bizana. The extracts showed good inhibitory activity with MIC values ranging from 0.39 to 12.5 mg/ml. The best activity was exhibited by DCM extracts of Rapanea melanophloeos, and EtOH extracts of Ficus craterostoma and Maesa lanceolata with MIC values of 0.098 mg/ml. The inhibitory activity against COX-1 enzyme was higher than COX-2, with 19 plant extracts for the former and 7 for the latter. All the tested plant extracts were not mutagenic at all concentrations tested against all tester strains of bacteria.

Conclusion

In view of the fact that the plants were selected based on their ethnobotanical usage for treating diarrhoea, the activities reported here goes a long way in validating the plants for traditional use.