贵州产五步蛇蛇毒磷脂酶A2的抗凝血及抗血栓作用研究

目的研究贵州产五步蛇蛇毒磷脂酶Ａ２的抗凝血及抗血栓作用。方法对大鼠静脉注射不同剂量的ＰＬＡ２,测定大鼠的凝血时间、凝血酶原时间、抗凝效价和血栓抑制率。结果ＰＬＡ２浓度达到１．０ｍｇ／ｋｇ以上,能显著延长大鼠凝血时间及凝血酶原时间,其抗凝效价相当于肝素钠的２４．８％～３１．５％。ＰＬＡ２能显著抑制大鼠实验性动脉及静脉血栓的形成。结论贵州产五步蛇ＰＬＡ２具有较强的抗凝血和抗血栓作用。     

Reproductive biology of female blue shark <Emphasis Type="Italic">Prionace glauca</Emphasis> in the southeastern Pacific Ocean

Polyandry is extremely common across a wide range of organisms. In promiscuous mating systems, females are often sexually harassed by males, but at the same time obtain benefits from multiple mating. It remains unclear whether polyandry is exclusively imposed by males or is also promoted by females. Here, we investigated this question by recording the time spent by female guppies near a single male or a group of males with similar size and colour patterns over three consecutive days. We accounted for the effect of shoaling by using a control treatment where a group of females was used instead of a group of males. Results showed that females spent significantly more time near the group of males, but not with the group of females. In the presence of a group of males, total female mating preference time did not change over the course of the study, but rather shifted from spending more time near the single male at the beginning of the experiment to spending more time near the group of males. The consequence of this female preference for associating with a group of males in a non-experimental setup would be to promote multiple mating. Our result indicates that polyandry in guppies is at least partially encouraged by females, and not entirely a consequence of male sexual behaviour.     

Chimeric contribution of human extended pluripotent stem cells to monkey embryos ex vivo

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Parapapillary Atrophy: Histological Gamma Zone and Delta Zone

Background

To examine histomorphometrically the parapapillary region in human eyes.

Methodology/Principal Findings

The histomorphometric study included 65 human globes (axial length:21–37 mm). On anterior-posterior histological sections, we measured the distance Bruch''s membrane end (BME)-optic nerve margin (“Gamma zone”), BME-retinal pigment epithelium (RPE) (“Beta zone”), BME-beginning of non-occluded choriocapillaris, and BME-beginning of photoreceptor layer. “Delta zone” was defined as part of gamma zone in which blood vessels of at least 50 µm diameter were not present over a length of >300 µm. Beta zone (mean length:0.35±0.52 mm) was significantly (P = 0.01) larger in the glaucoma group than in the non-glaucomatous group. It was not significantly (P = 0.28) associated with axial length. Beta zone was significantly (P = 0.004) larger than the region with occluded choriocapillaris. Gamma zone (mean length:0.63±1.25 mm) was associated with axial length (P<0.001;r² = 0.73) with an increase starting at an axial length of 26.5 mm. It was not significantly (P = 0.24) associated with glaucomatous optic neuropathy. Delta zone (present only in eyes with axial length of ≥27 mm) was associated with axial length (P = 0.001) and scleral flange length (P<0.001) but not with glaucoma (P = 0.73).

Conclusions/Significance

Parapapillary gamma zone (peripapillary sclera without overlying choroid, Bruch''s membrane and deep retinal layers) was related with axial globe elongation and was independent of glaucoma. Delta zone (no blood vessels >50 µm diameter within gamma zone) was present only in highly axially elongated globes and was not related with glaucoma. Beta zone (Bruch''s membrane without RPE) was correlated with glaucoma but not with globe elongation. Since the region with occluded choriocapillaris was smaller than beta zone, complete loss of RPE may have occurred before complete choriocapillaris closure.     

Human Stn1 protects telomere integrity by promoting efficient lagging-strand synthesis at telomeres and mediating C-strand fill-in

Telomere maintenance is critical for genome stability. The newly-identified Ctc1/Stn1/Ten1 complex is important for telomere maintenance, though its precise role is unclear. We report here that depletion of hStn1 induces catastrophic telomere shortening, DNA damage response, and early senescence in human somatic cells. These phenotypes are likely due to the essential role of hStn1 in promoting efficient replication of lagging-strand telomeric DNA. Downregulation of hStn1 accumulates single-stranded G-rich DNA specifically at lagging-strand telomeres, increases telomere fragility, hinders telomere DNA synthesis, as well as delays and compromises telomeric C-strand synthesis. We further show that hStn1 deficiency leads to persistent and elevated association of DNA polymerase α (polα) to telomeres, suggesting that hStn1 may modulate the DNA synthesis activity of polα rather than controlling the loading of polα to telomeres. Additionally, our data suggest that hStn1 is unlikely to be part of the telomere capping complex. We propose that the hStn1 assists DNA polymerases to efficiently duplicate lagging-strand telomeres in order to achieve complete synthesis of telomeric DNA, therefore preventing rapid telomere loss.     

HSP90 mRNA在胃癌和大肠癌中表达的研究

目的为探讨胃癌和大肠癌细胞HSP90 mRNA表达的特点.方法利用核酸原位杂交技术,对79例胃肠癌组织进行检测.结果表明HSP90 mRNA在胃癌和大肠癌中的阳性率分别为55.56%(15/27)和69.23%(36/52).mRNA表达与病理类型、分化程度和有否淋巴结转移有相关性.结论 HSP90 mRNA在胃肠癌中有较高表达,检测HSP90 mRNA可以作为提示预后的重要临床指标.     

大蒜芥属一新变种

发表了大蒜芥属一新变种,无毛全叶大蒜芥(Sisymbrium luteum (Maxim.)O. E. Schulz var. glabrum F. Z. Li et Z. Y. Sun.)。