A neural model of 3D shape-from-texture: multiple-scale filtering, boundary grouping, and surface filling-in

A neural model is presented of how cortical areas V1, V2, and V4 interact to convert a textured 2D image into a representation of curved 3D shape. Two basic problems are solved to achieve this: (1) Patterns of spatially discrete 2D texture elements are transformed into a spatially smooth surface representation of 3D shape. (2) Changes in the statistical properties of texture elements across space induce the perceived 3D shape of this surface representation. This is achieved in the model through multiple-scale filtering of a 2D image, followed by a cooperative-competitive grouping network that coherently binds texture elements into boundary webs at the appropriate depths using a scale-to-depth map and a subsequent depth competition stage. These boundary webs then gate filling-in of surface lightness signals in order to form a smooth 3D surface percept. The model quantitatively simulates challenging psychophysical data about perception of prolate ellipsoids [Todd, J., & Akerstrom, R. (1987). Perception of three-dimensional form from patterns of optical texture. Journal of Experimental Psychology: Human Perception and Performance, 13(2), 242-255]. In particular, the model represents a high degree of 3D curvature for a certain class of images, all of whose texture elements have the same degree of optical compression, in accordance with percepts of human observers. Simulations of 3D percepts of an elliptical cylinder, a slanted plane, and a photo of a golf ball are also presented.     

Early pregnancy losses in in vitro fertilization and oocyte donation

Objective: To evaluate prospectively the incidence of early pregnancy losses (before menstruation occurs) in IVF and ovum donation cycles.

Design: Prospective case-control study.

Setting: Tertiary care, university-associated center.

Patient(s): One hundred forty-five patients undergoing IVF and 92 undergoing oocyte donation were recruited. The control group for IVF consisted of 15 ovum donors who had no ET and were instructed to avoid intercourse. The control group for oocyte donation included 10 women undergoing a mock cycle of steroid replacement.

Intervention(s): Starting on day 6 after ET, the women were instructed to collect the first urine sample of the day every 2 days. Each patient collected six different specimens of urine (days 6, 8, 10, 12, 14, and 16 after ET for cases or the same days without ET for controls.

Main Outcome Measure(s): β-HCG was measured with a standardized microparticle enzyme immunoassay, and IVF reproductive outcome was assessed.

Result(s): For IVF, positive implantation was registered in 88 of 145 cycles of embryo replacement (60.7%). Only 30 (20.7%) resulted in viable pregnancies, whereas the remaining 58 miscarried. Forty-two of these miscarriages (72.4%) were early pregnancy losses and 13 (22.4%) were classified as clinical abortions. In ovum donation, positive implantation was recorded in 64 of 92 cycles of ET (69.6%). A total of 30 (32.6%) ended in viable pregnancies, whereas the remaining 34 (37.0%) were miscarriages. Early pregnancy loss accounted for 70.6% of pregnancy losses, whereas biochemical pregnancies and clinical abortions accounted for 11.8% and 17.6%, respectively.

Conclusion(s): Our results demonstrate that patients undergoing assisted reproductive technology have an increased rate of early pregnancy loss compared with fertile patients. In addition, these data indicate that implantation is more frequently impaired in IVF than in oocyte donation cycles, resulting in a high incidence of early pregnancy loss. This suggests that implantation may be subjected to abnormal conditions in assisted reproduction.     

Acute and chronic presentation of ectopic pregnancy may be two clinical entities

OBJECTIVE: The diagnosis of ectopic pregnancy (EP) is often confirmed at presentation (acute), but often requires serial beta-hCG levels to confirm the diagnosis (chronic). The purpose of this study is to analyze whether these clinical presentations represent a spectrum of disease. DESIGN: The retrospective cohort study of 452 patients diagnosed with EP at the University of Pennsylvania in the years 1990-1999. SETTING: University of Pennsylvania, Philadelphia, Pennsylvania. PATIENT(S): Four hundred fifty-two patients diagnosed with EP. Patients diagnosed with EP were divided into two groups according to the time of diagnosis. MAIN OUTCOME MEASURE(S): A total of 37 parameters were examined including historic and demographic factors, findings at presentation, and treatment and outcome variables. RESULT(S): The two groups were similar in terms of historic EP risk factors. Multivariable analysis demonstrates that women with a chronic presentation were less likely to have received fertility medications (odds ratio [OR] 0.23; 95% confidence interval [CI] 0.06-0.84), less likely to present with pain (OR 0.29; 95% CI 0.12-0.71), have a lower beta-hCG level at presentation (9,849 mIU/mL +/- 16,726 vs. 1,787 mIU/mL +/- 4,717), lower chance of rupture (OR 0.19; 95% CI 0.05-0.73), and less frequently have blood type 0. CONCLUSION(S): Women diagnosed with ectopic pregnancy can be categorized into two groups, those with an acute presentation and those with a chronic presentation. Differences in risk factors, presentation, and outcome may reflect differences in trophoblast viability or invasive potential.     

上海地区210名12周岁儿童CYP3A活性分布

目的:了解上海地区12岁儿童CYP3A酶活性的分布。方法:采用HPLC法测定尿液中氢化可的松和6β-羟基氢化可的松的浓度,以6β-羟基氢化可的松/氢化可的松的浓度比来表示CYP3A酶的活性。结果:210名受检者CYP3A酶的活性为(5.0±2.3),其中男性为(4.7±2.3),女性为(5.4±2.4)。结论:12岁儿童CYP3A酶活性无性别差异,正常值范围为0.96~26.55。     

抗蛋白酶3抗体检测及影响因素的研究

目的研究血清样本稀释度、封闭液、孵育条件、洗涤条件及酶标板包被后保存时间对血清抗蛋白酶3(PR3)抗体检测结果的影响。方法采用酶联免疫吸附试验(ELISA)对159份血清进行抗PR3抗体检测,并用受试者工作特征曲线(ROC曲线)分析确定阳性界限(cut-off)值。结果血清样本最佳稀释度为1∶50;5%脱脂奶粉封闭酶标板能有效地降低本底值;孵育缓冲液中加入牛血清白蛋白及脱脂奶粉比单用磷酸盐缓冲液(PBS)对测定值有明显影响。经ROC曲线分析实验的阳性临界值为正常阴性对照吸光度(A)值的2.5倍,灵敏度和特异性分别为84.62%和98.46%。结论血清抗PR3检测结果受血清样品稀释、封闭液、孵育条件及阳性临界值的选择等多因素的影响。     

Inhibition of homodimerization of Toll-like receptor 4 by curcumin

Toll-like receptors play a key role in sensing microbial components and inducing innate immune responses. Ligand-induced dimerization of TLR4 is required for the activation of downstream signaling pathways. Thus, the receptor dimerization may be one of the first lines of regulation in activating TLR-mediated signaling pathways and induction of subsequent immune responses. LPS induces the activation of NF-kappaB and IRF3 through MyD88- or TRIF-dependent pathways. Curcumin, a polyphenol found in the plant Curcuma longa, has been shown to suppress the activation of NF-kappaB induced by various pro-inflammatory stimuli by inhibiting IKKbeta kinase activity in MyD88-dependent pathway. Curcumin also inhibited LPS-induced IRF3 activation. These results imply that curcumin inhibits both MyD88- and TRIF-dependent pathways in LPS-induced TLR4 signaling. However, in TRIF-dependent pathway, curcumin did not inhibit IRF3 activation induced by overexpression of TRIF in 293T cells. These results suggest that TLR4 receptor complex is the molecular target of curcumin in addition to IKKbeta. Here, we report biochemical evidence that phytochemicals (curcumin and sesquiterpene lactone) inhibit both ligand-induced and ligand-independent dimerization of TLR4. Furthermore, these results demonstrate that small molecules with non-microbial origin can directly inhibit TLRs-mediated signaling pathways at the receptor level. These results imply that the activation of TLRs and subsequent immune/inflammatory responses induced by endogenous molecules or chronic infection can be modulated by certain dietary phytochemicals we consume daily.     

榄香烯对人喉鳞癌细胞生长抑制与凋亡诱导作用

目的探讨榄香烯对人喉鳞癌细胞株HEp2细胞的生长抑制作用,以及对半胱天冬氨酸蛋白酶3(Caspase3)活性的影响。方法采用四氮甲基唑蓝(MTT)法和流式细胞分析技术(FCM),研究榄香烯诱导人喉鳞癌细胞株HEp2细胞凋亡的作用;用比色法观察榄香烯诱导人喉鳞癌细胞株HEp2细胞凋亡时Caspase3活性的变化。结果榄香烯抑制HEp2细胞生长呈时间剂量依赖性,24hIC50值为69.297mg·L-1;榄香烯(60mg·L-1)和顺铂(3mg·L-1)联合用药可加强抑制作用;Caspase3活性在榄香烯作用12h达到最高,并随药物作用时间的延长而下降。结论榄香烯可诱导HEp2细胞凋亡,同时可引起Caspase3活性的改变。