三维能量多普勒超声鉴别宫颈过短孕妇先兆早产的作用研究

目的：使用三维能量多普勒超声比较先兆早产和无症状宫颈过短单胎孕妇的宫颈体积和血管指数。方法：预先扫描妊娠 24-34.6 周的300 例无症状健康孕妇的宫颈长度。将宫颈长度过短，小于孕周的10%的孕妇纳入无症状宫颈短组，测量该组孕妇宫 颈体积和血管指数（Ⅵ）、血管血流指数（VFI）和血流指数（FI）。先兆早产组患者入院的24 小时内测量同样的超声参数。记录孕妇 的体重指数、孕周、吸烟状况、经产状况、早产家族史、母亲为早产出生者以及之前的早产情况等数据。比较两组孕妇超声检查结 果和病史参数。结果：29 例无症状健康妇女（9.6%）宫颈较短。两组间的病史参数或宫颈长度无显著差异。先兆早产组的宫颈体积 较小（12.90 vs 17.168 cm3，P = 0.005）。无症状宫颈过短孕妇的VI 和VFI 均较低（VI：4.369% vs 15.939%，P<0.001；VFI：1.514 vs 4.878，P<0.001）。宫颈过短组的FI较高（33.581 vs 30.311，P=0.006）。结论：无症状宫颈过短组孕妇与先兆早产组孕妇之间的宫颈 长度类似，但两组间宫颈体积和血管指数存在差异。     

电针结合红外线照射对反复着床失败患者子宫内膜容受性、胚胎移植及妊娠情况的影响

目的:观察电针结合红外线照射对反复着床失败(RIF)患者子宫内膜容受性、胚胎移植及妊娠情况的影响。方法:选取102例于2015年5月-2018年5月在我院行复苏胚胎移植的RIF患者,按照随机数字表法将患者分为电针结合红外线照射治疗组(A组,38例)、安慰针刺组(B组,34例)及空白对照组(C组,30例)。比较三组治疗前后血清雌二醇、孕酮水平,于治疗前后检测子宫内膜容受性超声学指标,包括子宫内膜厚度、内膜容积、血管血流指数(VFI)、内膜血流指数(FI)、阻力指数(RI),比较三组胚胎移植及妊娠情况。结果:三组治疗前后血清雌二醇、孕酮水平比较无统计学差异(P0.05)。治疗后A组子宫内膜厚度、内膜容积大于治疗前及B组、C组,VFI、FI高于治疗前及B组、C组,RI低于治疗前及B组、C组(P0.05)。三组移植胚胎数、生化妊娠率、临床妊娠率比较无统计学差异(P0.05),A组胚胎着床率高于B组、C组(P0.05)。结论:电针结合红外线照射治疗RIF患者可以改善子宫内膜容受性,提高胚胎着床率。     

Role of endometrial blood flow assessment with color Doppler energy in predicting pregnancy outcome of IVF-ET cycles

This is a prospective study of 182 women (38 yrs or younger) undergoing IVF-ET. Endometrial thickness, echo pattern and blood flow on transvaginal ultrasonography were recorded eight hours prior to hCG administration. The patients were divided into three groups: A (n = 10) with undetectable endometrial blood flow; B (n = 82) with sub-endometrial blood flow; C (n = 90) with both endometrial and sub-endometrial blood flow. According to IVF-ET outcomes, all patients were re-divided into three groups: 1 non-pregnancy (n = 92); 2 intrauterine pregnancy with live fetus (n = 70); 3 others (n = 20 including biochemical pregnancy, embryonic diapause, ectopic pregnancy and miscarriage). Intrauterine pregnancy with live fetus in Group C (62.2%) was much higher than that in Group A and B (0% and 17.1%, p less than or equal to 0.001). The implantation rate (33.2%) was much higher than that in Group A and B (0% and 19.90%, p less than or equal to 0.001). The pulsatility index, resistance index, and S/D of endometrial spiral arteries were 0.1 +/- 0.2, 0.6 +/- 0.1 and 2.5 +/- 0.4 in Group 2, which were much lower than those in Group 1 and Group 3 (p1-2 less than 0.001, p2-3 less than 0.05). The patients with detectable endometrial blood flow had higher clinical pregnancy rates and implantation rates.     

TGF superfamily and MMP2, MMP9, TIMP1 genes expression in the endometrium of women with impaired reproduction

During the putative "implantation window", a period of maximal endometrial receptivity that spans 7-9 days after ovulation, a series of changes on the structural and molecular level occur that render the endometrium susceptible to implantation for the human embryo. Many members of the TGFbetas are expressed by human endometrium at different stages of menstrual cycle. Also studies regarding the MMP2 gene expression and activity of MMP2 in the implantation window have shown a higher expression and activity of MMP2 in women with impaired fertility. We have examined by RT-PCR the expression of TGFbeta2 and MMP2, MMP9 and TIMP1 in 28 patients with idiopathic infertility, 16 patients with unexplained recurrent miscarriage and 16 control women were enrolled in this study. Seven to nine days after ovulation endometrial biopsy by Pipelle or hysteroscopy was performed to assess the expression of TGFbeta2 , MMP2, MMP9 and TIMP1. We found that in endometria from women with idiopathic infertility TGFbeta2 expression was 2.8 fold higher than in endometria from control group and 2.1 fold higher in endometrial samples from women with unexplained recurrent miscarriage compared to the control group. The MMP2, MMP9 and TIMP1 expression in endometrial samples revealed no significant differences between the study groups and control group. There was a statistically significant negative correlation between TGFbeta2 and MMP9 expression in endometria from women in control group. The present investigations suggest that dysregulated TGFbeta2, MMP2, MMP9 and TIMP1 expression are associated with infertility and early pregnancy loss. However the exact mechanism of how overexpression of endometrial TGFbetaand MMPs interferes with implantation may be more complex.     

三维能量多普勒超声联合血清HE4、TK1、YKL-40对绝经后出血患者子宫内膜癌的预测价值

摘要 目的：研究三维能量多普勒超声联合血清人附睾蛋白4（HE4）、胸苷激酶1（TK1）、甲壳质酶蛋白40（YKL-40）对绝经后出血患者子宫内膜癌的预测价值。方法：选择我院2019年10月～2022年10月收治的150例绝经后出血患者。将其按照病理检查结果的差异分为子宫内膜癌组31例与子宫内膜良性增生组119例。对所有患者均开展三维能量多普勒超声检查,并检测血清HE4、TK1、YKL-40水平。以受试者工作特征曲线（ROC）分析三维能量多普勒超声联合血清HE4、TK1、YKL-40水平预测绝经后出血患者子宫内膜癌的效能。结果：子宫内膜癌组血流指数（FI）、血管形成指数（VI）、血管形成-血流指数（VFI）以及由该三参数构建的综合指数I相较于子宫内膜良性增生组均更高（均P＜0.05）。子宫内膜癌组血清HE4、TK1、YKL-40水平相较于子宫内膜良性增生组均更高（均P＜0.05）。经ROC曲线分析发现：三维能量多普勒超声联合血清HE4、TK1、YKL-40水平预测绝经后出血患者子宫内膜癌的曲线下面积（AUC）、灵敏度、特异度以及约登指数均高于上述四项单独预测。结论：三维能量多普勒超声联合血清HE4、TK1、YKL-40水平预测绝经后出血患者子宫内膜癌的效能较佳。     

Pericyte deficiencies lead to aberrant tumor vascularizaton in the brain of the NG2 null mouse

Tightly regulated crosstalk between endothelial cells and pericytes is required for formation and maintenance of functional blood vessels. When the NG2 proteoglycan is absent from pericyte surfaces, vascularization of syngeneic tumors growing in the C57Bl/6 mouse brain is aberrant in several respects, resulting in retardation of tumor progression. In the NG2 null mouse brain, pericyte investment of the tumor vascular endothelium is reduced, causing deficiencies in both pericyte and endothelial cell maturation, as well as reduced basal lamina assembly. While part of this deficit may be due to the previously-identified role of NG2 in β1 integrin-dependent periyte/endothelial cell crosstalk, the ablation of NG2 also appears responsible for loss of collagen VI anchorage, in turn leading to reduced collagen IV deposition. Poor functionality of tumor vessels in NG2 null brain is reflected by reduced vessel patency and increased vessel leakiness, resulting in large increases in tumor hypoxia. These findings demonstrate the importance of NG2-dependent pericyte/endothelial cell interaction in the development and maturation of tumor blood vessels, identifying NG2 as a potential target for anti-angiogenic cancer therapy.     

The early revascularization of membranous bone

The experimental finding that membranous onlay bone grafts maintain volume and viability to a greater extent than do endochondral grafts may be related to the more rapid vascularization of membranous bone. Microangiographic techniques were used to study the rates of vascularization of membranous and endochondral bone grafts in adult white New Zealand rabbits at 1, 3, 7, 14, and 21 days after bone grafting. Vascularization patterns were quantified microscopically using a modified point-counting technique. At 3 days, membranous bone grafts demonstrated vessel ingrowth from both soft tissue and host bone. Little ingrowth was seen in endochondral grafts. By day 7, 2.5 vessels per square were identified entering membranous grafts, while an average of 0.6 vessels per square were counted for endochondral bone grafts. At day 14, there was an average of greater than 20 vessels per square for membranous grafts versus 1.8 for their endochondral counterparts. At 21 days, the endochondral grafts demonstrated persistent avascular central areas not seen in membranous grafts. Membranous onlay bone grafts in the rabbit are more rapidly vascularized than endochondral grafts. This factor may affect the greater volume maintenance seen in experimental membranous grafts.     

Evaluation of etiology and pregnancy outcome in recurrent miscarriage patients

The purpose of this study was to evaluate etiology and pregnancy outcome of recurrent miscarriage women. The enrolled patients (280) were evaluated for Triiodothyronine, Thyroxine, Thyroid stimulating hormone, prolactin, chromosomal analysis, Haemoglobin A1C, blood sugar, Magnetic resonance imaging, 3D-ultrasound, auto-antibodies profile (antiphospholipid antibodies, anticardiolipin antibodies, lupus anticoagulant, antinuclear antibodies, anti-thyroid antibodies and β2 glycoprotein1), torch profile (Toxoplasmo gondii, rubella, cytomegalo virus and herpes simplex virus), blood vitamin D3 levels, psychological factors, Body mass index and thrombotic factors (protein S and C deficiency, Prothrombin G20210A mutation, anti-thrombin III, Factor V Leiden and Methylenetetrahydrofolate reductase mutation), uterosalpingography (hysteronsalpingography) and hysteroscopy. The therapeutic regimens either singly or combined were employed for the treatment of recurrent miscarriage patients on the basis of etiology (single or multiple) and include intravenous immunoglobulin, low molecular weight heparin, low dose aspirin, levothyroxine, progesterone, folic acid, human chorionic gonadotrophin, vitamin D3, psychotherapy, genetic counselling. However, patients with idiopathic recurrent miscarriage were treated with progesterone supplementation, anticoagulation and/or immune modulatory agents. The incidence of primary recurrent miscarriage was highest and most of the women experienced recurrent miscarriage during first trimester. Endocrinological disorders (39%) were found as the major pathological factor for recurrent miscarriage. Other factors include uterine abnormalities (5.7%), vitamin D3 deficiency (3.5%), psychological factors (3.2%) infection (3.6%), autoimmune abnormalities (1.8%) and protein S deficiency (1.8%). However, 40% cases were idiopathic. The overall live birth rate achieved after the management of recurrent miscarriage patients was 75.7%. Enocrinopathy was the major cause of recurrent miscarriage. The overall live birth rate achieved was 75.7% with highest pregnancy outcome in secondary recurrent miscarriage patients after the management.     

Common definition for categories of clinical research: a prerequisite for a survey on regulatory requirements by the European Clinical Research Infrastructures Network (ECRIN)

Background

Idiopathic recurrent miscarriage is defined as 3 consecutive pregnancy losses with no contributing features found on investigations. At present there are no treatments of proven efficacy for idiopathic recurrent miscarriage. Uterine natural killer (uNK) cells, the most predominant leucocyte in the endometrium are adjacent to foetal trophoblast cells and thought to be involved in implantation. The exact mechanisms of how uNK cells affect implantation are not clear but are probably through the regulation of angiogenesis. Multiple studies have shown an association between high density of uterine natural killer cells and recurrent miscarriage. We have shown that prednisolone reduces the number of uNK cells in the endometrium. The question remains as to whether reducing the number of uNK cells improves pregnancy outcome.

Methods

We propose a randomised, double-blind, placebo controlled trial of prednisolone with a pilot phase to assess feasibility of recruitment, integrity of trial procedures, and to generate data to base future power calculations. The primary aim is to investigate whether prednisolone therapy during the first trimester of pregnancy is able to improve live birth rates in patients with idiopathic recurrent miscarriage and raised uNK cells in the endometrium. Secondary outcomes include conception rate, karyotype of miscarriage, miscarriages (first and second trimester), stillbirths, pregnancy complications, gestational age at delivery, congenital abnormality and side effects of steroids. The trial has 2 stages: i) screening of non-pregnant women and ii) randomisation of the pregnant cohort. All patients who fit the inclusion criteria (<40 years old, ≥3 consecutive miscarriages with no cause found and no contraindications to prednisolone therapy) will be asked to consent to an endometrial biopsy in the mid-luteal phase to assess their levels of uNK cells. Women with high levels of uNK cells (≥5%), will be randomised to either prednisolone or placebo when a pregnancy is confirmed. Follow-up includes 2 weekly ultrasound scans in the first trimester, an anomaly scan at 20 weeks gestation, growth scans at 28 and 34 weeks gestation and a postnatal follow-up at 6 weeks.

Trial Registration

Current Controlled Trials ISRCTN28090716     

Blockade of adhesion molecule CD146 causes pregnancy failure in mice

Unexplained pregnancy loss and recurrent miscarriage seriously impair human fecundity. However, the underlying molecular mechanisms remain elusive. Recent studies suggest that the adhesion molecule CD146 may be involved in unexplained recurrent miscarriage. Here, we investigate the effect of CD146 on early pregnancy. Using in situ hybridization and immunohistochemistry, we found that CD146 was specifically expressed in the receptive maternal uteri and invasive embryonic trophoblasts during the early stages of pregnancy, but it was completely absent in the non-pregnant uterus. Our in vitro studies demonstrated that blocking CD146 with a function-perturbation antibody AA98 significantly inhibited the attachment of blastocysts onto the receptive uterine luminal epithelial monolayer, the trophoblastic outgrowth of blastocysts and ectoplacental cones, and the secretion of matrix metalloproteinases. Animal experiments showed that applying this antibody before embryo implantation caused pregnancy failure in mice. Our data present direct evidence for the role of CD146 in mediating embryonic attachment and trophoblastic invasion, and provide new insight into the molecular mechanism underlying unexplained pregnancy loss and recurrent miscarriage.     

EphB4 controls blood vascular morphogenesis during postnatal angiogenesis

Guidance molecules have attracted interest by demonstration that they regulate patterning of the blood vascular system during development. However, their significance during postnatal angiogenesis has remained unknown. Here, we demonstrate that endothelial cells of human malignant brain tumors also express guidance molecules, such as EphB4 and its ligand ephrinB2. To study their function, EphB4 variants were overexpressed in blood vessels of tumor xenografts. Our studies revealed that EphB4 acts as a negative regulator of blood vessel branching and vascular network formation, switching the vascularization program from sprouting angiogenesis to circumferential vessel growth. In parallel, EphB4 reduces the permeability of the tumor vascular system via activation of the angiopoietin-1/Tie2 system at the endothelium/pericyte interface. Furthermore, overexpression of EphB4 variants in blood vessels during (i) vascularization of non-neoplastic cell grafts and (ii) retinal vascularization revealed that these functions of EphB4 apply to postnatal, non-neoplastic angiogenesis in general. This implies that both neoplastic and non-neoplastic vascularization is driven not only by a vascular initiation program but also by a vascular patterning program mediated by guidance molecules.     

Quantitative histochemical and stereological study of alkaline phosphatase in the rat thyroid gland

Summary The histochemical alkaline phosphatase reaction in thyroid vascular endothelium was estimated spectrophotometrically and stereologically. Thus two main characteristics of the reaction were obtained: 1. the average enzyme activity, reflecting the level of transport processes in the capillary-thyrocyte system; 2. the relative volume of functioning vessels. An index of thyroid vascularity is proposed that is equal to the product of these two characteristics. The changes of the primary characteristics as well as of the vascularity index, caused by experimental hypo- and hyperplasia of the gland, are discussed.     

Regional hypoxia elicits regional changes in chorioallantoic membrane vascular density in alligator but not chicken embryos

Hypoxic incubation increases vascularization in the chick chorioallantoic membrane (CAM). The effect of regional hypoxia on the vascular density of American alligator (Alligator mississippiensis) and chicken (Gallus gallus) CAMs was studied to determine if hypoxic proliferation of blood vessels is localized or global across the CAM. Eggs were incubated under normoxic conditions with a portion of the eggshell covered with non-toxic beeswax to induce external regional hypoxia. CAMs were examined under a microscope with a 'bulls eye' coverslip and a vascular density index (VDI) was determined. The hypoxic portions of the alligator CAMs were more vascular than the normoxic portions (VDI = 200.9 versus 157. 8, respectively). Presumably this response is maladaptive by causing increased blood flow to the poorly oxygenated portions, i.e. increased 'shunt'. Thus, we hypothesize increased vascularity due to hypoxic incubation is due to local release and subsequent rapid local breakdown or uptake of angiogenic factors. In contrast, the hypoxic and normoxic portions of the chick CAMs exhibited virtually no difference in VDI (VDI= 211.5 versus 217.9, respectively). We suggest the air cell and air space of the chicken eggs allows for circulation of gas in ovo, eliminating the possibility of regional internal hypoxia.     

Differential expression of the vascular endothelial growth factor-receptor system in the gravid uterus of yorkshire and Meishan pigs

Litter size in the pig is limited by uterine capacity, which is dependent on uterine size, placental size, and vascularity. Placentae of U.S. pig breeds, such as the Yorkshire, exhibit marked growth from mid to late gestation, increasing their surface area of endometrial attachment. In contrast, placentae of the prolific Chinese Meishan pig exhibit little growth from mid to late gestation; instead, they exhibit a marked and progressive increase in the density of placental blood vessels. Vascular endothelial growth factor (VEGF) is a potent angiogenic and permeability-enhancing factor that is produced and secreted by placentae of several species, including the pig. The activity of VEGF is mediated through two specific receptors (VEGF-R1 and VEGF-R2), both of which are expressed by placental and endometrial tissues in pigs and are thought to play a role in mediating increased vascularization and/or permeability at the fetal-maternal interface. The objectives of the present study were to determine concentrations of VEGF in fetal blood and placental fluids as well as placental and adjacent endometrial mRNA expression of VEGF, VEGF-R1, and VEGF-R2 on Days 30, 50, 70, 90, and 110 of gestation in Yorkshire and Meishan pigs. Day 90 Meishan conceptuses exhibited marked increases (P < 0.05) in placental VEGF mRNA expression as well as fetal blood and allantoic fluid concentrations of VEGF, which remained elevated through Day 110. In contrast, Yorkshire conceptuses failed to exhibit increases in placental VEGF mRNA expression or concentrations of VEGF in fetal blood or allantoic fluid until Day 110. Receptor mRNA expression patterns differed between Meishan and Yorkshire conceptuses, but no difference was found in their expression levels. Placental efficiency (fetal weight/placental weight) was higher (P < 0.05) on Days 90 and 110 in Meishan than in Yorkshire conceptuses. The earlier increase in VEGF protein and mRNA expression in the Meishan versus the Yorkshire conceptus may explain the previously reported increased vascularity and increased placental efficiency of this breed compared the Yorkshire breed.     

No correlation between pinopode formation and LIF and MMP2 expression in endometrium during implantation window

Implantation depends on two factors - embryo and endometrium. The period of maximal endometrial receptivity is a poorly understood phenomenon. We decided to look at three possible markers of implantation: pinopodes, leukemia inhibitory factor, and matrix metalloproteinase 2 and their correlations. We included in the study 23 idiopathic infertility patients and 21 patients with recurrent spontaneous abortions of unknown etiology. Twenty one fertile patients were also recruited. A biopsy was used for endometrial dating according to the Noyes and Hertig criteria, and assessed for the presence of pinopodes via a scanning electron microscope. Endometria were examined in Real Time-Polymerase Chain Reaction cycles for the mRNA expression of leukemia inhibitory factor (LIF) and matrix metalloproteinase 2 (MMP2). No difference was found in the stage of pinopodes development, nor in the coverage of endometrial surface between the studied groups. The expression level for LIF mRNA was lower in control patients compared to idiopathic infertility and recurrent miscarriage patients. No difference was detected in the expression of MMP2 between all studied groups. No correlation was found between pinopodes development stage and LIF and MMP2 expressions in endometrium. Of the studied factors, LIF and pinopodes show the most promise as potential markers of endometrial receptivity. However, the results achieved suggest that these markers are independent of each other.     

Relationship between placental vascular endothelial growth factor expression and placental/endometrial vascularity in the pig

We investigated the temporal association between placental vascular endothelial growth factor (VEGF), a potent stimulator of angiogenesis and vascular permeability, and changes in placental/endometrial vascularity on selected days throughout gestation in the pig. Placental and endometrial tissues were collected from sows on Days 25 (n = 4), 36 (n =6), 44 (n = 6), 70 (n =5), 90 (n =5 ), and 112 (n = 7) of gestation. Cross sections of the placental/endometrial interface of each conceptus were used to estimate the number of blood vessels per unit area via image analysis and the intensity of VEGF staining via immunohistochemistry. Placental tissues were also collected on these days to evaluate VEGF mRNA expression. Placental VEGF mRNA expression and the numbers of blood vessels per unit area of placental and adjacent endometrial tissue were low and decreasing from Day 25 to Day 44, before increasing (P < 0.05) markedly and progressively through Day 112. These data are consistent with the marked increase in VEGF immunostaining in the chorionic and uterine luminal epithelium from early to late gestation. Further, these increases in placental VEGF mRNA were positively correlated with fetal weight (r = 0.73; P < 0.0001) and placental efficiency (fetal weight/placental weight ratio; r = 0.66, P < 0.0001). These data are consistent with a role for VEGF in increasing the number of blood vessels at the placental endometrial interface, resulting in an increased capacity for nutrient transfer from the maternal to the fetal compartment.     

Evidence of a bi-phasic effect of thrombospondin-1 on angiogenesis

Contradictory results have been reported regarding the association between vascularity (used as an index of angiogenesis) and thrombospondin-1 (TSP-1) in human tumours. In previous studies, the reported association was based on the estimated average TSP-1 value per tumour, with a sufficient number of specimens collectively analysed per tumour type. Given the extent of intra-tumour heterogeneity, we determined the association between TSP-1 and vascularity within individual specimens, based on the average values of TSP-1 and vascularity in 10–20 pre-selected areas per tumour. Cells expressing TSP-1 mRNA were visualised by in situ hybridisation and quantified by point counting. Vascularity was quantified by point counting and vessel density of von Willebrand Factor-positive vessels. In 10 ductal breast carcinomas, a direct correlation between TSP-1 and vascularity was found in 4 tumours, no correlation in 3 and an inverse correlation in 3. The effect of TSP-1 on endothelial cell migration in vitro was assessed in the Boyden chamber assay. TSP-1 stimulated cell migration at low concentrations (0.1–10g/ml) and was inhibitory at high concentrations (25–100g/ml). These results suggest that TSP-1 may elicit a concentration-dependent, bi-phasic, effect on angiogenesis.     

Vessel destruction by tumor-targeting Salmonella typhimurium A1-R is enhanced by high tumor vascularity

Our laboratory has previously developed a tumor-targeting double-auxotrophic mutant of Salmonella typhimurium termed A1-R. The present report demonstrates that S. typhimurium A1-R destroys tumor blood vessels and this is enhanced in tumors with high vascularity. Red fluorescent protein (RFP)-expressing Lewis lung cancer cells (LLC-RFP) were transplanted subcutaneously in the ear, back skin, and footpad of nestin-driven green fluorescent protein (ND-GFP) transgenic nude mice, which selectively express GFP in nascent blood vessels. Color-coded in vivo imaging demonstrated that the LLC-RFP ear tumor had the highest cell density and the footpad tumor had the least with the ear tumor having more abundant blood vessels than that on the back or footpad. The tumor-bearing mice were treated with A1-R bacteria via tail-vein injection. Tumors in the ear were the earliest responders to bacterial therapy and hemorrhaged severely the day after A1-R administration. Tumors growing in the back were the second fastest responders to bacterial treatment and appeared necrotic 3 days after A1-R administration. Tumors growing in the footpad had the least vascularity and were the last responders to A1-R. Therefore, tumor vascularity correlated positively with tumor efficacy of A1-R. The present study suggests that bacteria efficacy on tumors involved vessel destruction which depends on the extent of vascularity of the tumor.