Kindergarten children's representation and understanding of written number symbols

Two samples of kindergarten children's representation and understanding of written number symbols were examined in two time points in one academic year. About 85% of Chinese five year olds (mean = 5 years 10 months) were able to use conventional number symbols to represent the quantity of 30 or larger. At the end of the kindergarten year, 94% of Chinese six year olds (mean = 6 years 4 months) were able to use conventional number symbols to represent the quantity of 100 or larger. Some Chinese six year olds had problems in representing written addition and subtraction tasks. Children's ability to represent written number symbols, ability to represent written addition and subtraction formula and their performance on written addition and subtraction were closely related. The performance of children in a university-affiliated childcare center was better than that of the center serving working-class families in Time 1, but the performance reversed at the end of the kindergarten year.     

核磁共振法测定非离子表面活性剂 HLB 值的研究 2.几种混合体系 HLB 值的测定与计算

本文应用核磁共振法(NMR)测定了几种混合体系的 HLB 值与混合体系中各组分的 HLB 值。实验结果表明,混合体系中各组分在核磁共振图谱中的积分曲线高度也具有加和性。混合体系的 HLB 值是体系中各组分 HLB 值的加权平均值。因此,对混合体系的 HLB 值可以应用 NMR 法直接测定,也可应用 NMR 法测定各组分的 HLB值,通过计算求得,计算值与实测值完全一致。     

螺旋CT三期扫描对肝纤维化诊断价值研究

目的探讨螺旋CT三期扫描对肝纤维化的诊断价值。方法对66例经肝穿刺活检病理证实的慢性乙型肝炎肝纤维化患者组和42例正常对照组进行螺旋CT三期增强扫描。根据纤维化程度分期进行影像资料和相关指标的统计分析。结果肝左叶增大,肝表面形态及肝实质密度的改变,脾脏增大,门静脉增宽和侧枝循环的建立等影像学改变,随着肝纤维化严重程度的加重而有统计学差异。本研究显示57例肝纤维化患者螺旋CT三期扫描诊断肝纤维化52例,敏感性91.2%,特异性77.8%。各期肝纤维化分期准确28例,准确率49.1%;准确判断轻度纤维化(S1、S2)或重度纤维化(S3、S4)44例,准确率77.2%,诊断早期肝硬化16例,准确率84.2%。结论螺旋CT三期扫描能判断肝纤维化的程度,而且是动态观察肝纤维化的病程演进和临床随访的有效手段。     

Stimulation of Alpha-Adrenoceptors Facilitates the Release of Growth Hormone-Releasing Hormone from Rat Hypothalamus in vitro

While extensive evidence suggests that adrenoceptors play an important role in the control of growth hormone in the rat, there are few studies involving the direct measurement of growth hormone-releasing hormone (GHRH). We have therefore developed a radioimmunoassay for rat GHRH, and used it to investigate the modulation of GHRH release by noradrenaline from incubated rat hypothalamus in vitro. The GHRH radioimmunoassay had no significant cross-reactivity with other hypothalamic or GHRH-related peptides, and was sensitive to 4 pg/tube; intra- and interassay coefficients of variation were 6% and 12% respectively. Single incubated rat hypothalami produced a stable and readily measurable output of GHRH in successive 20 min incubations after an initial 60 min preincubation; the release of GHRH was increased in the presence of 56 mM KCI, but did not respond to KCI-depolarization when calcium was excluded from the medium. Stimulated GHRH release was identical to synthetic rat GHRH(1–43) on high-performance liquid chromatography and Sephadex G-75 chromatography.
Noradrenaline stimulated GHRH secretion in a dose-dependent manner in the concentration range 10⁻¹⁰— 10⁻⁶M, with a plateau in response at 10⁻⁷M. Stimulation with noradrenaline 10⁻⁷M was blocked by idazoxan 10⁻⁵M and attenuated by thymoxamine 10⁻⁵M, but was unaffected by timolol 10⁻⁵M. Both the α₂-adrenoceptor agonist guanfacine, and the α₁-adrenoceptor agonist methoxamine, specifically stimulated GHRH secretion.
It is concluded that noradrenaline stimulates the release of GHRH at both α₁ and α₂-adrenoceptors.     

医学数字化影像与PACS系统

随着医学影像技术的迅速发展,出现了各种医学成像设备,许多全新的数字化影像技术已用于临床,丰富了形态医学诊断的信息和层次.它主要表现在如下几个方面:1、透视与摄影的数字X线设备相继产生,如DR、CR、DF、DSA,并成为放射诊断学科的一个重要突破.因此,传统的X线设备正逐步为数字化设备所取代.2、新的成像方法不断地发展,工作站的强大的后处理功能使得这些方法得以实现.3、目前PACS成为医学影像技术的新课题,在放射科得到了广泛的应用.PACS不仅是一个产品,而且是一个系统工程.在PC的硬件软件环境下发展起来的PACS成为它的一个发展趋势.     

JAK2激酶抑制剂AG490对结肠癌HT-29细胞侵袭性的影响

目的观察JAK2激酶抑制剂AG490对结肠癌HT-29细胞侵袭以及对基质金属蛋白酶-2（MMP-2）表达的影响，探讨STAT3信号转导通路在结肠癌侵袭转移调控中的作用。方法应用JAK2激酶抑制剂AG490处理结肠癌HT-29细胞，Matrigel肿瘤体外侵袭模型检测肿瘤细胞侵袭；Western blot检测STAT3蛋白表达；逆转录-聚合酶链反应（RT—PCR）检测MMP2mRNA表达。结果AG490可抑制JAK2／STAT3信号转导通路活化及结肠癌HT-29细胞侵袭，在此过程中AG490在mRNA水平抑制MMP-2表达。结论STAT3信号转导通路参与结肠癌细胞侵袭调控，阻断STAT3通路活化可抑制结肠癌细胞侵袭，这一作用可能是通过抑制MMP-2表达实现的。     

头皮电烧伤骨外露带毛发皮瓣修复

目的：探讨头皮电烧伤骨外露用头皮扩张皮瓣移植修复的临床效果。方法：采用早期扩创,保留部分坏死骨质,用邻近头皮扩张使带毛发的头皮面积扩大后移植覆盖创面,电性失活骨质在血循环良好的皮瓣覆盖下,为周边及基底健康骨质生长起到支架作用,皮瓣扩张到一定面积后移植到裸露骨质上,使其得以修复。结果：在治疗的9例中,除1例皮瓣边缘在1．5cm×1．5cm坏死外,其余皮瓣全部成活,未发生感染坏死,创面均一次性封闭。结论：头皮电烧伤骨外露扩张后皮瓣带毛发修复,可缩短创面愈合时间,外形较好,易掌握,效果较为满意。     

腹腔镜胆囊切除术360例Calot三角解剖与临床

目的 通过腹腔镜胆囊切除术(Laparoscopic Cholecystec-tomy，LC)，探讨Calot三角的解剖关系。方法 从Calot三角分离出胆囊动脉、胆囊管，辨认胆总管和肝总管的走向。结果 我们1998年9月～2004年6月共完成360例LC术进行分析。结论 解剖Calot三角是胆囊切除术中重要的步骤，也是预防医源性损伤的关键。     

济川煎加味治疗老年糖尿病合并便秘24例

便秘是老年糖尿病患者的常见合并症之一.笔者自2006年6月～2007年6月以济川煎为基础方加味治疗老年糖尿病患者合并便秘24例,现报道如下. 　　……     

全腹膜外补片植入术中补片不固定的实验研究

目的评价全腹膜外补片植入术中补片不固定的安全性和有效性。方法将50只SD大鼠建立疝缺损(3cm2)模型,按随机数字表分为2组,使用聚丙烯补片(12 cm2)采用腹膜外补片植入术进行修复。甲组为补片固定组,乙组为补片不固定组。大鼠于术后不同时间分批处死,记录补片的挛缩度、腹壁抗张强度以及组织细胞学变化。结果所有大鼠术后腹腔均无粘连。2组大鼠在术后7 d、14 d、30 d、60 d和90 d补片的挛缩度分别为6.7%±1.3%vs 7.3%±1.5%、12.3%±1.3%vs 12.4%±1.6%、14.0%±2.0%vs 14.5%±1.3%、17.4%±2.1%vs 18.4%±1.5%和18.9%±2.2%vs19.5%±2.6%(P>0.05);2组大鼠的腹壁抗张强度分别为(288.4±8.4)mm Hg vs(286.6±10.2)mm Hg、(300.4±11.2)mm Hg vs(298.8±11.4)mm Hg、(305.0±11.7)mm Hg vs(303.3±16.1)mm Hg、(309.0±10.8)mm Hg vs(307.6±8.9)mm Hg和(311.8±9.8)mm Hg vs(310.0±8.6)mm Hg(P>0.05);2组大鼠的组织细胞学变化一致。结论当补片面积是大鼠疝缺损的4倍以上时,不固定的腹膜外补片植入术是安全有效的。