直接法与统计法测试松质骨孔隙率的比较研究

目的 探讨松质骨孔隙率的测试方法。方法 对15根猪胫骨分别采用“直接法”与“统计法”测试松质骨孔隙率或其表观密度和材料密度。结果 （1）孔隙率与表观密度呈非常显著负相关,而与材料密度相关不显著;（2）孔隙率沿轴向靠近密质量骨逐渐减小,而沿横向基本不变;（3）统计法可测出松质骨各个层面的孔隙率大小。结论 直接法和统计法均能检测松质骨孔隙率,但统计法较直接法更能反映孔隙率的分布与变化规律。     

Simultaneous Construct Surface Microstructural and Internal Network-Like Conductive Pathways of Poly(l-lactic acid)/Carbon Nanomaterials Composite Foams

The poly(l -lactic acid) (PLLA)/carbon nanomaterials composite foams with hierarchical surface microstructural and internal conductive pathways are successfully prepared by a simple crystallization-assisted rapid phase separation (CARPS). The dimension and morphology of carbon nanomaterials can induce different crystallization forms to construct the hierarchical surface microstructure, and they are distributed on the phase interface of solvent and non-solvent to form conductive pathways. It is found that the heterogeneous nucleation of nanomaterials promotes a significant increase in crystallinity, and a stacked granular structure formed on the surface promotes the increase of the water contact angle to 148.7°. Foams with interconnecting pore structures contribute to the formation of 85.3% porosity and 12.33 g g⁻¹ oil absorption. Carbon nanomaterials are distributed on the pore walls of the porous foam, which converts the foam from an insulating material to a conducting polymer. Furthermore, the uniform distribution of nanomaterials significantly affects the thermal stability of the PLLA. In belief, the multifunctional biodegradable foam, prepared by a CARPS method, makes it promising for industrial production and has potential applications in electrical conductivity, oil-water separation, and many other fields.     

Nondomain biopolymers: Flexible molecular strategies to acquire biological functions

A long-standing assumption in molecular biology posits that the conservation of protein and nucleic acid sequences emphasizes the functional significance of biomolecules. These conserved sequences fold into distinct secondary and tertiary structures, enable highly specific molecular interactions, and regulate complex yet organized molecular processes within living cells. However, recent evidence suggests that biomolecules can also function through primary sequence regions that lack conservation across species or gene families. These regions typically do not form rigid structures, and their inherent flexibility is critical for their functional roles. This review examines the emerging roles and molecular mechanisms of “nondomain biomolecules,” whose functions are not easily predicted due to the absence of conserved functional domains. We propose the hypothesis that both domain- and nondomain-type molecules work together to enable flexible and efficient molecular processes within the highly crowded intracellular environment.     

列车乘务员SCL—90评定结果分析

采用ＳＣＬ—９０症状自评量表对某铁路分局４６７名列车乘务员的心理卫生状况进行了分析。结果显示总均分、阳性症状均分、阳性项目数、九组症候群因子分、达到或超过中等严重程度的发生频数均显著高于对照组。经多元逐步回归分析,仅细菌总数和二氧化碳对列车乘务员心理卫生状况有一定影响,其原因多与工作环境的不良因素和工作性质有关。     

鼻咽癌中与已知基因同源的差异表达cDNA序列

采用新近发展的ｃＤＮＡ代表性差异分析法筛选鼻咽癌中不表达的或表达降低的ｃＤＮＡ序列。结果显示：有９个与已知基因高度同源的ｃＤＮＡ序列。通过对这些已知基因的结构和功能分析,发现有与细胞骨架成分相关的基因：αａｃｔｉｎｉｎ,ｅｚｒｉｎ和细胞角蛋白１３;直接与瘤基因和抑瘤基因相互作用的基因：鲨烯合成酶和ＴＲＩＰ１基因;直接参与ＤＮＡ合成以及调控基因转录和翻译的基因：ＴＡＦⅡ６８和组蛋白Ｈ１０;另外还有人类补体因子Ｂ及类转运ＲＮＡ合成酶的基因。这些基因大多具有相当于抑瘤基因的功能。从而进一步说明鼻咽癌的发生是多基因相互作用的结果。     

n-Hexane neuropathy caused by addictive inhalation: clinical and electrophysiological features

To assess the clinical and electrophysiological features of n-hexane neuropathy caused by addictive inhalation, 4 patients were studied in the progressive phase. The neurological manifestations were characterized by subacute predominantly motor polyneuropathy and disease progression despite discontinuance of the chemicals, which were similar to those reported in industrial exposure, although with a severer degree associated with anorexia and body weight loss. Electrophysiological studies showed that all showed multifocal conduction block and profound conduction slowing, as well as features of axonal degeneration. Sural nerve biopsy showed axonal loss, axonal swelling, and thin myelin probably due to retraction by axonal swelling. n-Hexane abuse causes severe subacute polyneuropathy. The mixed axonal and demyelinating electrophysiological features were consistent with peculiar pathological findings. Conduction block, probably due to paranodal myelin retraction or ongoing wallerian degeneration, is very frequent and could be responsible for the clinical deficits, especially in the early phase of illness.     

Effects of topical epinephrine on aqueous humor dynamics in the cat

The purpose of this study was to investigate, in cats, the effects of topical epinephrine on aqueous humor dynamics as measured by the non-invasive method of fluorophotometry and by other methods. Measurements were carried out on 12 cats before and after one week of twice daily treatment with 2% epinephrine hydrochloride to one eye. Aqueous flow and outflow facility were determined using fluorophotometry. Uveoscleral outflow was calculated from these results and was evaluated with anterior chamber perfusion of FITC-dextran. Outflow facility also was measured by tonography. Epinephrine-treated eyes, compared with their baseline values, showed a 31% reduction in intraocular pressure (P<0.001), a 23% reduction in aqueous flow (P<0.05), a 60% increase in fluorophotometric outflow facility (P<0.05), and a 43% increase in tonographic outflow facility (P<0.05). Treated eyes, compared with contralateral control eyes, showed a 27% reduction in IOP (P<0.005), a 25% reduction in aqueous flow (P<0.005), a 38% increase in fluorophotometric outflow facility (P<0.05), and a 34% increase in tonographic outflow facility. When evaluated by both fluorophotometry and FITC-dextran tracer methods, epinephrine had no significant effect on uveoscleral outflow. It was concluded that, in cats treated with topical epinephrine twice daily for a week, a reduction in intraocular pressure is induced by an increase in outflow facility and decrease in aqueous flow.     

诱发型一氧化氮合酶在人类鼻黏膜上皮细胞中的表达

目的　探讨人类鼻黏膜上皮细胞应答炎性刺激因子白细胞介素 1 β(interleukin 1 β ,IL 1 β)和肿瘤坏死因子 (tumornecrosisfactor α ,TNF α) ,合成诱发型一氧化氮合酶 (induciblenitricoxidesynthase ,iNOS)的能力及其机制 ,以及类固醇药物对上皮细胞的影响。方法　将人类鼻黏膜上皮细胞(包括鼻息肉上皮细胞 ,下鼻甲上皮细胞 )进行无血清原代细胞培养 ,分别加入各种不同浓度的炎性刺激因子 (IL 1 β和TNF α)以及地塞米松 ,采用原位杂交的方法检测不同条件下iNOSmRNA的水平。结果　①不论用IL 1 β或是TNF α刺激 ,iNOSmRNA水平均随浓度的增加 ,时间的延长而增加 ,尤以鼻息肉上皮细胞明显。但当浓度到一定水平后 ,iNOSmRNA水平不再继续升高 ;②用IL 1 β +TNF α共同刺激 ,iNOSmRNA水平要高于单纯用其中的一种 (P <0 .0 1 ) ,同样鼻息肉上皮细胞iNOSmRNA水平要高于下鼻甲上皮细胞 ;③加入地塞米松后 ,被炎性因子诱发的iNOSmRNA升高的水平下降。当地塞米松浓度为 4 0ng/ml以上时 ,iNOSmRNA水平不再继续下降。 结论　①IL 1 β和TNF α上调人类鼻黏膜上皮细胞合成的iNOSmRNA水平 ,鼻息肉上皮细胞更为活跃。它的机制可能是通过核因子 κB途径 ;②地塞米松降低这种上调作用 ,它的机制可能是通过阻断核     

The effect of megestrol acetate on growth of HepG2 cells in vitro and in vivo.

PURPOSE: Hepatocellular carcinoma (HCC) is generally considered as a sex hormone-dependent tumor, and hormonal therapy has been proposed as a strategy for the treatment of HCC. The aim of the study is to investigate the effect of megestrol acetate, a synthetic progesteronal agent, on growth of HepG2 cells in vitro and in vivo. EXPERIMENTAL DESIGN: Cell growth in vitro was assessed by a colormetric method, and cell growth in vivo was assessed by tumor volumetrics. RESULTS: Megestrol acetate was shown to inhibit the growth of HepG2 cells in vitro in dose- and time-dependent manners with an IC (50) of 260 microm (24-h incubation). The growth of HepG2 cell-transplanted tumors in nude mice was also inhibited by i.p. injection of megestrol acetate (10 mg/kg/day). The tumor volumes of the megestrol acetate-treated group regressed to 59% of controls by week 6 and to 41% of controls by week 13. Apoptosis following G(1) arrest was observed in megestrol acetate-treated cells and may be a mechanism through which megestrol acetate inhibits HepG2 cells. Megestrol acetate was also demonstrated to have a beneficial effect on the weight gain of tumor-bearing nude mice, and the mean weight of the megestrol acetate-treated animals was higher than that of controls from week 4 of the treatment period, and the differences were statistically significant in week 5 and 6 (P < 0.05, compared with controls). No significant survival advantage was, however, demonstrated in the treatment group. CONCLUSIONS: This study showed that megestrol acetate inhibited the growth of HepG2 cells grown in vitro and in vivo. These data provide useful information for clinical study of megestrol acetate for the treatment of HCC.