Assessment of the mutagenicity of dichloroacetic acid in lacI transgenic B6C3F1 mouse liver

Dichloroacetic acid (DCA) is a chlorination byproduct found in finished drinking water. When administered in drinking water this chemical has been shown to produce hepatocellular adenomas and carcinomas in B6C3F1 mice over the animal's lifetime. In this study, we investigated whether mutant frequencies were increased in mouse liver using treatment protocols that yielded significant tumor induction. DCA was administered continuously at either 1.0 or 3.5 g/l in drinking water to male transgenic B6C3F1 mice harboring the bacterial lacI gene. Groups of five or six animals were killed at 4, 10 or 60 weeks and livers removed. At both 4 and 10 weeks of treatment, there was no significant difference in mutant frequency between the treated and control animals at either dose level. At 60 weeks, mice treated with 1.0 g/l DCA showed a 1.3-fold increase in mutant frequency over concurrent controls (P = 0.05). Mice treated with 3.5 g/l DCA for 60 weeks had a 2.3-fold increase in mutant frequency over the concurrent controls (P = 0.002). The mutation spectrum recovered from mice treated with 3.5 g/l DCA for 60 weeks contained G:C-->A:T transitions (32.79%) and G:C-->T:A transversions (21.31%). In contrast, G:C-->A:T transitions comprised 53.19% of the recovered mutants among control animals. Although only 19.15% of mutations among the controls were at T:A sites, 32.79% of the mutations from DCA-treated animals were at T:A sites. This is consistent with the previous observation that the proportion of mutations at T:A sites in codon 61 of the H-ras gene was increased in DCA-induced liver tumors in B6C3F1 mice. The present study demonstrates DCA-associated mutagenicity in the mouse liver under conditions in which DCA produces hepatic tumors.      

Fatty acid balance studies in term infants fed formula milk containing long-chain polyunsaturated fatty acids

Long-chain polyunsaturated fatty acids (LCP) are thought to be required for optimal nervous system development in the newborn. A commercial milk formula containing LCP (Aptamil-LCP) with a fatty acid profile closely resembling breast milk, has recently been introduced for term infants. The absorption of fatty acids in term infants was examined in a double-blind randomized controlled trial comparing Aptamil-LCP ( n = 20) and standard Aptamil ( n = 20). Formula-fed newborn infants were studied from birth for 14 d. Fat balances (3 d) were performed from d 10. A 3-d stool collection was performed from d 10 in a parallel breastfed group ( n = 21). Plasma samples were taken on d 6. Median fat excretion (mg kg⁻¹) was 897.1, 615.0 and 355.2 with Aptamil, Aptamil-LCP and breastfeeding, respectively. The median total fat absorption coefficient in Aptamil-LCP-fed infants was higher than in those fed standard Aptamil ( p < 0:01). These findings were accounted for by differences in the excretion and absorption of long-chain saturated fatty acids (C14:0, C16:0 and C18:0). Higher fat excretion was associated with bulkier and firmer stools. Only trace amounts of LCP were detected in the stools of all groups. This accounted for less than 4% of dietary intake in Aptamil-LCP-fed infants. No differences in the utilization of LCP from Aptamil-LCP and breast milk feeding were apparent. Plasma phospholipid fatty acid composition data reflected differences in dietary LCP intake. Thus, PL LCP levels were highest in the breastfed infants and lowest in the Aptamil-fed infants, with values for the Aptamil-LCP-fed group falling in between.     

安徽省2007～2008年志贺氏菌流行株菌型分布及脉冲场分子分型

目的了解安徽省志贺氏菌的流行菌型,并建立脉冲场凝胶电泳（PFGE）分子分型方法,为菌痢防控提供理论基础。方法对22株志贺氏菌进行血清分型、药物敏感试验和PFGE试验。结果22株志贺氏菌血清分型：B群19株,占总数86.5%;C群1株,占总数的4.5%;D群2株,占总数的9.0%。成功建立了菌痢的PFGE分子分型方法,并将我省22株流行株分为若干带型。试验结果进一步作聚类分析。结论安徽省菌痢流行株以福氏为主;安徽省PFGE分子分型方法和初步带型数据库对提高细菌检测水平有一定意义。     

Thrombocytopoietic properties of oncostatin M

Oncostatin M (OM) is a 28-kD glycoprotein that exhibits a panoply of biologic effects. Based on histologic observations of increased splenic megakaryocytes in nude mice implanted with an OM-secreting cell line, the thrombocytopoietic properties of OM in mice were investigated in culture and in vivo. Alone, OM did not induce megakaryocytic colony formation, but in combination with murine interleukin-3 (IL-3), OM markedly enhanced colony formation. The effects of OM on colony formation were similar to those of IL-6. OM alone augmented acetylcholinesterase in short-term marrow cultures. In normal mice, the administration of OM augmented platelet counts without increasing other circulating blood cell counts. The increment in counts exceeded that observed with IL-6. The kinetics of the OM response suggested that maximal increases in platelets occurred 3 days after the cessation of OM administration, irrespective of the duration of administration. In irradiated mice, OM administration accelerated platelet recovery and prevented the decrease in red blood cells observed in irradiated control animals. The data show that OM behaves as a megakaryocytic maturation factor in vitro and augments platelet production in vivo. Based on these animal data, OM may have potential clinical utility as a thrombocytopoietic agent.     

Development of spinal cord ischemia after clamping of noncritical segmental arteries in the pig.

BACKGROUND: Blood flow to the thoracolumbar spinal cord is thought to be critically dependent on the arteria radicularis magna. We investigated whether spinal cord blood supply becomes dependent on other, noncritical, segmental arteries if spinal cord perfusion pressure (SCPP) is decreased. The SCPP is equal to the mean arterial pressure (MAP) minus the cerebrospinal fluid (CSF) pressure (SCCP = MAP - CSF). METHODS: The thoracoabdominal aorta was exposed in 10 pigs. Functional integrity of spinal cord motor pathways was assessed with myogenic motor-evoked potentials after transcranial electrical stimulation (tc-MEPs). Using this technique, a group of segmental arteries not critical for spinal cord blood supply was identified. Before, during, and after clamping of the noncritical segmental arteries, spinal cord ischemia was produced by decreasing SCPP by means of increasing CSF pressure, and the SCPP threshold at which tc-MEPs showed evidence of spinal cord ischemia was determined. Ischemic SCPP thresholds, obtained during and after clamping of the noncritical segmental arteries, were compared with the ischemic threshold obtained before clamping (control value). RESULTS: Before noncritical segmental arteries were clamped, ischemic tc-MEP changes occurred when the SCPP was below 15 +/- 5 (SD) mm Hg. With a total of 9 +/- 3 (SD) segmental arteries clamped, the ischemic SCPP threshold was 48 +/- 14 mm Hg (p < 0.01). After the release of all clamps, ischemia occurred at a SCPP of 15 +/- 5 (SD) mm Hg. CONCLUSIONS: In this porcine experiment, clamping of originally noncritical segmental arteries significantly reduced the tolerance of the spinal cord to a decrease in SCPP.     

柠檬酸对分化型甲状腺癌患者首次131I治疗后唾液腺功能的保护作用

目的：探讨柠檬酸对术后首次行¹³¹I治疗（简称清甲治疗）的分化型甲状腺癌（DTC）患者唾液腺功能的影响,阐明柠檬酸对¹³¹I治疗的甲状腺癌患者唾液腺功能的保护作用。方法：经患者知情同意,随机选择准备首次行¹³¹I治疗的68例甲状腺乳头状癌患者,随机分为对照组和柠檬酸组,每组34例。对照组患者无特殊准备,柠檬酸组患者于¹³¹I治疗前1周及治疗后3周内每天含柠檬酸1 min（0.2 g/次）后吐出。2组患者分别于¹³¹I治疗前24 h及¹³¹I治疗后3个月行2次^99mTcO^4-唾液腺显像检查,计算第15分钟摄取指数（15 min UI）和排泌分数（SR）,评估唾液腺功能。结果：与¹³¹I治疗前比较,对照组患者¹³¹I治疗后右侧腮腺和双侧颌下腺15 min UI差异无统计学意义（P>0.05）,左侧腮腺15 min UI降低（P<0.05）;与¹³¹I治疗前比较,柠檬酸组患者¹³¹I治疗后双侧腮腺及双侧颌下腺15 min UI差异无统计学意义（P>0.05）;与对照组比较,柠檬酸组患者¹³¹I治疗前后双侧腮腺和双侧颌下腺15 min UI差异均无统计学意义（P>0.05）。与¹³¹I治疗前比较,对照组患者双侧腮腺治疗后SR降低（P<0.05）,双侧颌下腺SR差异无统计学意义（P>0.05）,柠檬酸组患者双侧腮腺和双侧颌下腺治疗后SR差异无统计学意义（P>0.05）;与对照组¹³¹I治疗后比较,柠檬酸组患者双侧腮腺SR升高（P<0.05）,双侧颌下腺SR差异无统计学意义（P>0.05）。结论：DTC患者术后首次¹³¹I治疗后唾液腺排泌功能可能受损,短期口含柠檬酸对唾液腺具有保护作用,可以减轻唾液腺的放射性损伤。     

游离黏膜组织重建尿道治疗复杂性尿道狭窄的临床研究

目的 探讨利用游离黏膜一期尿道成形治疗复杂性尿道狭窄或闭锁的疗效。方法 2000年8月至2004年7月采用2种游离黏膜一期尿道成形术治疗73例复杂性尿道狭窄。术前42例已行耻骨上膀胱造瘘，余31例最大尿流率1．2～6．5ml／s。用游离结肠黏膜(n=22)重建尿道长10～18cm，平均13cm；用口腔黏膜(n=51)重建尿道长3～11cm，平均5cm。术后随访分别行逆行尿道造影及尿流率，部分患者行尿道镜检查。结果随访2～48个月，平均19个月。术后排尿通畅67例(91．8％)。发生再次狭窄4例，其中结肠黏膜重建者1例，口腔黏膜重建者3例；排尿欠畅2例，定期行尿道扩张；尿道皮肤瘘2例；结肠腹壁瘘1例。1例结肠黏膜重建尿道者术后47个月移植物活检示结肠黏膜的组织形态学基本无变化。结论口腔与结肠黏膜均可作为较理想的尿道替代物，口腔黏膜较适合狭窄段不长的尿道修复，结肠黏膜较适合复杂性超长段尿道狭窄或缺损的治疗。     

超声对甲状腺术后瘢痕组织的诊断应用

甲状腺术后瘢痕组织是甲状腺局部分切除术后由于手术方式及缝线填充而形成的组织,甲状腺术后瘢痕组织形成及其发生发展过程同一般的组织损伤修复病理过程一样,为渐进老化阶段的结缔组织,其内小血管稀少,胶原纤维增多[1]。由于甲状腺术后瘢痕组织其质地较硬,活动性差,超声声像图上表现缺乏典型特征,与癌灶极其相似,因此鉴别较困难。本文将介绍超声对于甲状腺术后的随诊应用,分析甲状腺术后瘢痕组织的超声检查特点并着重介绍超声动态观察甲状腺术后瘢痕组织的应用及其发展前景。     

吡柔比星(THP)膀胱灌注预防腺性膀胱炎术后复发的疗效观察

目的 评价吡柔比星(THP)膀胱灌注预防腺性膀胱炎术后复发的疗效。方法 对30例腺性膀胱炎患者行经尿道汽化电切术,术后定期应用THP(40mg/50ml)膀胱内灌注化疗。结果 30例患者随访5～20个月,平均14.5个月,3例复发(10％)。未见有全身性药物不良反应,仅2例血白细胞降至3000个/ml。结论THP膀胱灌注预防腺性膀胱炎术后复发疗效满意,病人耐受性好,副作用小。