抗血管生成因子Angiostatin与Endostatin作用下肿瘤血管生成的二维数值模拟

目的数值模拟抗血管生成因子Angiostatin和Endostatin对肿瘤血管生成的影响。方法建立肿瘤内外血管生成的二维离散数学模型。模型耦合两种抗血管生成因子Angiostatin和Endostatin的抑制效应,数值模拟在促血管生成因子诱导下肿瘤微血管网生成,讨论血管生成抑制因子的影响。结果抗血管生成因子Angiostatin对肿瘤内外血管网络生成的速度和成熟度有抑制作用。抗血管生成因子Angiostatin和Endostatin耦合作用时,在肿瘤血管生成的早期有明显的抑制效应;在肿瘤血管生成的中后期,它们可以降低肿瘤血管化程度。结论本文模型能够较好的模拟抗血管生成因子Angiostatin和Endostatin对内皮细胞迁移和增殖的抑制作用。     

Indocyanine green video angiographies help to identify burns requiring operation

The key decision in the treatment of thermal injuries is the determination of the depth of the burn wound and the resultant decision on treatment options. The trend in the treatment of deep dermal and full thickness burns is toward very early excision and grafting to reduce the risk of infection, decrease scar formation, shorten hospital stay, and thereby reducing costs. Traditionally, this has involved serial clinical examinations, which involves primarily subjective judgment. Various objective examination techniques, supplementing the clinical diagnosis, have been suggested, but none has yet achieved widespread clinical acceptance. It has frequently been postulated that the blood flow in injured tissue indicates the extent of tissue damage. In this study, the clinical and scientific impact of indocyanine green (ICG) video angiography was tested in 20 patients. A wide range of depth of injury and etiology was included and analyzed. In all cases considered, video angiography was possible. The measurements and observations correlated well with the actual burn depth, which was assessed clinically (pre- and intraoperative assessment) and histologically (biopsies). In conclusion, ICG video angiography seems to be a practical method to describe vascular patency in a burn wound. The results indicate that ICG fluorescence angiography is a practical, accurate, and effective adjunct to clinical methods for estimating burn wound depth and thereby to assist in the rational assessment of treatment options. Furthermore, it allows an objective, qualitative and quantitative observation of the dynamic changes in burn wound depth, which are observed during the acute post-burn period, thereby indicating optimal timing of the first operation.     

Thrombosis at venous insertion sites after inferior vena caval filter placement

Color Doppler flow imaging or compression ultrasound (US) was used to prospectively determine frequency of thrombosis at 54 venous insertion sites (47 in common femoral veins, seven in right internal jugular veins) after percutaneous placement of Greenfield filters for interruption of the inferior vena cava. Fifty-one filters were successfully placed in 51 patients with a dilator set or a balloon angioplasty catheter. Nine focal thrombi were detected in the common femoral vein (19%) and one in the right internal jugular vein (14%). Use of dilators induced eight thrombi (24%), compared with two (10%) from balloon catheters. The left common femoral vein had a high frequency of thrombosis, regardless of dilation technique (five of nine). Of nine patients with acute common femoral vein thrombosis, four became symptomatic within 10 days after the procedure. Patients may remain asymptomatic or have delayed symptoms; thus, US is valuable for determining patients at risk of thrombosis of the common femoral vein.     

The iliac angle: a sonographic marker of trisomy 21 during the midtrimester: dependency of fetal lying?

The aim of this study was to evaluate the efficiency of the fetal iliac wing angle measurements in the detection of trisomy 21 during the second trimester and the impact of the fetal position on this measurement. During a 43-month period, the iliac wing angle was prospectively measured in 695 fetuses at genetic ultrasonography performed before amniocentesis. The iliac wing angle measurements were performed in a true axial section of the fetal pelvis and the relative position of the fetal spine was recorded (decubitus, lateral). Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and likelihood ratio (LR) were computed for multiple cutoff angles. The prevalence of trisomy 21 was 1.4%; 447 fetuses were in lateral position, 240 fetuses were in decubitus position, including, respectively, 2 and 8 fetuses with trisomy 21 (8 fetuses with other chromosomal anomalies were excluded). In euploid fetuses, the mean iliac wing angle was 83.7° in decubitus and 68.7° in lateral position; in fetuses with trisomy 21 the respective mean angles were 104.9° and 102.5°. A receiver operating characteristics (ROC) curve provided an absolute cutoff angle of 90°, predicting trisomy 21 with a sensitivity of 100%, a specificity of 72.4%, an NPV of 100%, a PPV value of 11.1%, and an LR of 3.6. The measurement of iliac wing angles in an axial section of the fetal pelvis is dependent on spine orientation and provides an efficient cutoff angle for the exclusion of trisomy 21 in patients at risk.     

Selective increase of dark phase water intake in neuropeptide-Y Y2 and Y4 receptor knockout mice

Neuropeptide-Y (NPY) is involved in the regulation of ingestive behaviour and energy homeostasis. Since deletion of the NPY Y2 and Y4 receptor gene increases and decreases food intake, respectively, we examined whether water intake during the light and dark phases is altered in Y2 and Y4 receptor knockout mice. The water consumption of mice staying in their home cages was measured by weighing the water bottles at the beginning and end of the light phase during 4 consecutive days. Control, Y2 and Y4 receptor knockout mice did not differ in their water intake during the light phase. However, during the dark phase Y2 and Y4 receptor knockout mice drank significantly more (46-63%, P<0.05) water than the control mice. The total daily water intake over 24 h was also enhanced. The enhanced water intake during the dark phase was not altered by the beta-adrenoceptor antagonist propranolol or the angiotensin AT1 receptor antagonist telmisartan (each injected intraperitoneally at 10 mg/kg). These data indicate that NPY acting via Y2 and Y4 receptors plays a distinctive role in the regulation of nocturnal water consumption. While beta-adrenoceptors and angiotensin AT1 receptors do not seem to be involved, water intake in Y2 and Y4 receptor knockout mice may be enhanced because presynaptic autoinhibition of NPY release and inhibition of orexin neurons in the central nervous system are prevented.