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101.
102.
甘肃临夏盆地的晚中新世红粘土堆积中含有大量的三趾马动物群化石,其中犀科化石,特别是大唇犀最为丰富。通过对临夏盆地晚中新世具有代表性的大唇犀化石的年龄结构的分析,初步了解到化石群各年龄段个体的百分比和种群动态。大唇犀化石中成年个体的数量占优势,明显多于老年个体,与正常生活群中的年龄结构吻合,由此可初步断定是突发性事件引起了犀牛种群的灾害性死亡。再进一步对化石的风化、磨蚀、聚集状态及所受的水动力特征等进行分析,发现骨骼受到了弱水流的短距离搬运,说明化石埋藏地离动物死亡地不远。以上分析结果与沉积学特征相结合,说明临夏盆地晚中新世三趾马动物群的集群死亡可能与严重的干旱化事件有关。  相似文献   
103.
本研究旨在检测男性尿道炎患者中尿道多形核白细胞数量,并进行解脲脲原体(Uu)培养,以评价非淋病奈瑟菌性尿道炎的临床意义。将2284例男性性病患者的尿道分泌物涂片,亚甲蓝(美蓝)染色后镜检多形核白细胞,并体外培养尿道分泌物的Uu。结果显示,645例患者(28.2%)Uu培养阳性,其中158例(24.5%)≥5个多形核白细胞,157例(24.3%)1~4个多形核白细胞,330例(51.2%)无多形核白细胞。218例阳性患者(33.8%)无症状,614例阳性患者(95.2%)无体征。男性尿道多形核白细胞数量在Uu培养阳性和阴性患者中存在显著差异(P0.01)。结果提示临床诊断与实验室检查在证实男性非淋病奈瑟菌性尿道炎中具有重要意义。  相似文献   
104.
选用了21种野生真菌,分别以PBS(磷酸缓冲液)浸提,浸提液进行兔红血球血凝活性测定,结果显示:冬虫夏草(Cordyceps sinensis)、蜜环菌(Armillariella mellea)、翘鳞肉齿菌(Sarcodon imbricatus)等不能使兔红血球凝集,显阴性;其余真菌均能使兔红血球凝集,其中以棱柄白马鞍菌(Helvella crispa)和美味牛肝菌(Boletus edulis)效价最高26;盘状马鞍菌(Helvella pezizoids)次之25;其余的均为20~23.取PBS浸提效价较高的6种样品棱柄白马鞍菌、盘状马鞍菌、真姬离褶伞(Lyophyllum shimeji)、红菇腊伞(Hygrophorus russula)、美味牛肝菌、离褶伞(Lyophyllum)等分别用Tris、NaAcetate(乙酸钠)、Glycin(甘氨酸)等不同pH缓冲液浸提,浸提液进行兔红血球血凝活性测定,结果显示:显弱酸性或弱碱性的缓冲液浸提时,浸提液对兔红血球血凝活性效价高于中性缓冲液,浸提真菌样品时最好使用弱酸或弱碱性缓冲液.  相似文献   
105.
In the present study, we examined the ability of immature germinal vesicle (GV) and subjected to in vitro matured (MII) yak oocytes to survive after cryopreservation as well as their subsequent development following in vitro maturation and fertilization. Both GV and MII oocytes were cryopreserved by using two different vitrification solutions (VS); VS-I contained 10% ethylene glycol (EG) and 10% dimethylsulfoxide (DMSO) in TCM-199 + 20% (v/v) fetal calf serum (FCS) whereas VS-II contained 40% EG + 18% Ficoll + 0.5 M sucrose in TCM-199 + 20% FCS. The percentage of oocytes found to be morphologically normal was greater (P < 0.01) in VS-I group than in VS-II group. Rates of cleavage (30.6–42.2%) and blastocyst formation (2.9–8.9%) did not differ among groups, but were lower than in unfrozen control (55.7% and 25.4%, P < 0.01). These results show that a combination of EG and DMSO or EG, Ficoll and sucrose can be used to cryopreserve yak oocytes in French straws.  相似文献   
106.
Alterations of mitochondrial DNA (mtDNA) have been associated with the risk of a number of human cancers; however, the relationship between mtDNA copy number in peripheral blood leukocytes (PBLs) and the risk of prostate cancer (PCa) has not been investigated. In a case-control study of 196 PCa patients and 196 age-paired healthy controls in a Chinese Han population, the association between mtDNA copy number in PBLs and PCa risk was evaluated. The relative mtDNA copy number was measured using quantitative real-time PCR; samples from three cases and two controls could not be assayed, leaving 193 cases and 194 controls for analysis. PCa patients had significantly higher mtDNA copy numbers than controls (medians 0.91 and 0.82, respectively; P<0.001). Dichotomized at the median value of mtDNA copy number in the controls, high mtDNA copy number was significantly associated with an increased risk of PCa (adjusted odds ratio  = 1.85, 95% confidence interval: 1.21–2.83). A significant dose-response relationship was observed between mtDNA copy number and risk of PCa in quartile analysis (Ptrend = 0.011). Clinicopathological analysis showed that high mtDNA copy numbers in PCa patients were significantly associated with high Gleason score and advanced tumor stage, but not serum prostate-specific antigen level (P = 0.002, 0.012 and 0.544, respectively). These findings of the present study indicate that increased mtDNA copy number in PBLs is significantly associated with an increased risk of PCa and may be a reflection of tumor burden.  相似文献   
107.
Many patients with pancreatic cancer have metastases to distant organs at the time of initial presentation. Recent studies examining the evolution of pancreatic cancer at the genetic level have shown that clonal complexity of metastatic pancreatic cancer is already initiated within primary tumors, and organ-specific metastases are derived from different subclones. However, we do not yet understand to what extent the evolution of pancreatic cancer contributes to proteomic and signaling alterations. We hypothesized that genetic heterogeneity of metastatic pancreatic cancer results in heterogeneity at the proteome level. To address this, we employed a model system in which cells isolated from three sites of metastasis (liver, lung, and peritoneum) from a single patient were compared. We used a SILAC-based accurate quantitative proteomic strategy combined with high-resolution mass spectrometry to analyze the total proteome and tyrosine phosphoproteome of each of the distal metastases. Our data revealed distinct patterns of both overall proteome expression and tyrosine kinase activities across the three different metastatic lesions. This heterogeneity was significant because it led to differential sensitivity of the neoplastic cells to small molecule inhibitors targeting various kinases and other pathways. For example, R428, a tyrosine kinase inhibitor that targets Axl receptor tyrosine kinase, was able to inhibit cells derived from lung and liver metastases much more effectively than cells from the peritoneal metastasis. Finally, we confirmed that administration of R428 in mice bearing xenografts of cells derived from the three different metastatic sites significantly diminished tumors formed from liver- and lung-metastasis-derived cell lines as compared with tumors derived from the peritoneal metastasis cell line. Overall, our data provide proof-of-principle support that personalized therapy of multiple organ metastases in a single patient should involve the administration of a combination of agents, with each agent targeted to the features of different subclones.Approximately half of the patients with pancreatic cancer are initially diagnosed with metastases to distal sites, with the commonest sites being the liver, lung, and peritoneum (1). Therapeutic strategies against metastases could help reduce the high mortality rates associated with this cancer (2). Understanding the nature of metastatic pancreatic cancer at a systems level can enable the discovery of potential targets for the development of targeted therapies.Pancreatic cancer has been shown to be a genetically evolving and heterogeneous disease (35). Clonal diversity and evolution of cancer genomes have also been demonstrated based on the isolation of distinct clonal populations purified directly from patient biopsies by means of flow cytometry followed by genomic characterization (6). A number of reports have documented the adoption of a proteomic approach for the discovery of potential biomarkers in pancreatic cancer (7, 8). However, these studies generally assume pancreatic cancers to be homogeneous, and the emphasis is placed on identifying molecules that are common across a broad array of tumors. There is a lack of studies systematically examining the proteomic changes or signaling pathways across pancreatic cancers to dissect the nature of the heterogeneity of each clone. An excellent setting in which the heterogeneity of tumors can be studied systematically is in a patient harboring metastases to several distant sites. To this end, we chose cells isolated from three metastatic pancreatic lesions of a single patient. The exomes of each tumor site were previously sequenced to study the progression of pancreatic cancer, and the results showed that all cell lines were identical for the genetic status of driver mutations (e.g. KRAS, TP53, and SMAD4) (9). Our hypothesis was that a better understanding of the proteomic consequences of the heterogeneity derived from genetic changes, and possibly other types of alterations, might provide additional opportunities to identify therapeutic targets.In order to precisely quantify differences across the proteomes of multiple metastatic pancreatic cancer lesions, we employed a SILAC-based1 quantitative proteomics strategy combined with high-resolution mass spectrometry (10, 11). Based on changes observed at the whole-proteome level, we found that a class of cell surface receptors showed significant enrichment with the highest alteration of their expression among the three metastatic pancreatic cancer cell lines examined (i.e. peritoneum, lung, and liver). Because the total protein levels provide information about the static levels of proteins and not their activity per se, we decided to examine the activation of phosphorylation-driven pathways, many of which are activated by cell surface receptors. To globally examine tyrosine phosphorylation-based signaling pathways, we carried out mass spectrometric analysis of purified tyrosine phosphorylated peptides enriched using anti-phosphotyrosine antibodies. As a result, we observed differential activation of tyrosine kinases in the three different sites of metastases. For example, Axl receptor tyrosine kinase was found to be hyperphosphorylated in lung and liver metastases relative to peritoneal metastasis. Expression of Axl receptor tyrosine kinase in primary and matched pancreatic cancers on tissue microarrays was validated by immunohistochemistry. Given such unique patterns of activation of pathways, it was possible that tumors derived from different sites could show differences in their sensitivity to pathway inhibitors. To test this, we performed experiments in which we screened cell lines derived from each metastatic site against a panel of small molecule inhibitors. We observed that the three metastatic pancreatic cancers had differential sensitivities to different inhibitors. For example, cells derived from the peritoneal metastasis were highly sensitive to lapatinib, whereas greater sensitivity to the Axl inhibitor R428 was observed in the lung metastasis cell line. Finally, we showed that treatment of mice bearing xenografts from these different pancreatic cancer cell lines with R428, an inhibitor of Axl receptor tyrosine kinase, led to reduction of tumors with evidence of activation of Axl.  相似文献   
108.
布氏田鼠摄食量、累积摄食量与日龄的关系   总被引:2,自引:3,他引:2  
布氏田鼠 (Microtusbrandti)是内蒙古典型草原区的主要害鼠 ,其危害方式主要表现之一为与牲畜争夺牧草资源[1,4 ,11,12 ] 。准确地测定其日食量(DFC)与累积摄食量 (CFC) ,对于定量地衡量该鼠的危害程度 ,进一步推算鼠害防治的经济阈值有着重要的意义。一些学者着手有关该鼠食性与食量 ,以及非取食性牧草消耗量的研究工作[3 ,7~ 9] 。但由于受实验手段的限制 ,一直未能解决布氏田鼠日食量、累积摄食量与田鼠年龄的关系等难题。本文以测定典型草原区布氏田鼠日食量与体重的关系 ,结合布氏田鼠体重与年龄的数学关系方程 …  相似文献   
109.
This paper presents a fully enclosed duck‐shaped triboelectric nanogenerator (TENG) for effectively scavenging energy from random and low‐frequency water waves. The design of the TENG incorporates the freestanding rolling mode and the pitch motion of a duck‐shaped structure generated by incident waves. By investigating the material and structural features, a unit of the TENG device is successfully designed. Furthermore, a hybrid system is constructed using three units of the TENG device. The hybrid system achieves an instantaneous peak current of 65.5 µA with an instantaneous output power density of up to 1.366 W m?2. Following the design, a fluid–solid interaction analysis is carried out on one duck‐shaped TENG to understand the dynamic behavior, mechanical efficiency, and stability of the device under various water wave conditions. In addition, the hybrid system is experimentally tested to enable a commercial wireless temperature sensor node. In summary, the unique duck‐shaped TENG shows a simple, cost‐effective, environmentally friendly, light‐weight, and highly stable system. The newly designed TENG is promising for building a network of generators to harvest existing blue energy in oceans, lakes, and rivers.  相似文献   
110.
The oral microbiota influences health and disease states. Some gram‐negative anaerobic bacteria play important roles in tissue destruction associated with periodontal disease. Lactoferrin (LF) and lactoperoxidase (LPO) are antimicrobial proteins found in saliva; however, their influence on the whole oral microbiota currently remains unknown. In this randomized, double‐blinded, placebo‐controlled study, the effects of long‐term ingestion of LF and LPO‐containing tablets on the microbiota of supragingival plaque and tongue coating were assessed. Forty‐six older individuals ingested placebo or test tablets after every meal for 8 weeks. The relative abundance of bacterial species was assessed by 16S rRNA gene high‐throughput sequencing. Most of the bacterial species in supragingival plaque and tongue coating that exhibited significant decreases in the test group were gram‐negative bacteria, including periodontal pathogens. Decreases in the total relative abundance of gram‐negative organisms in supragingival plaque and tongue coating correlated with improvements in assessed variables related to oral health, such as oral malodor and plaque accumulation. Furthermore, there was significantly less microbiota diversity in supragingival plaque at 8 weeks in the test group than in the placebo group and low microbiota diversity correlated with improvements in assessed variables related to oral health. These results suggest that LF and LPO‐containing tablets promote a shift from a highly diverse and gram‐negative‐dominated to a gram‐positive‐dominated community in the microbiota of supragingival plaque and tongue coating. This microbial shift may contribute to improvements in oral health, including oral malodor and state of the gingiva.
  相似文献   
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