Michaelis—Menten兼有一级消除动力学模型平均稳态时的一些特性

本文将Rowland等人的二房室模型中的消除过程扩展成米氏兼一级消除过程。据此,推导出达到稳态浓度的时间、血药浓度-时间曲线下面积和生物利用度的公式;进而得到平均清除率和剂量间的关系以及剂量与平均清除率和血浆浓度呈线性关系的结论。     

无蒂型结膜乳头状瘤临床分析

目的分析和探讨无蒂型结膜乳头状瘤的临床和病理特征、治疗方法及其疗效。方法对23例(23眼)无蒂型结膜乳头状瘤患者的临床、病理资料及手术方法进行回顾性分析。结果23例患者均经病理证实为结膜乳头状瘤,其中3例还可见鳞状上皮细胞呈巢状或团块状浸润性生长,提示癌变。对23例患者均进行术后随访,时间为2～5年,平均随访时间为(4.6±1.6)年,无1例失访。在行羊膜移植的21例患者中,76.2%(16/21)在羊膜术后4周内吸收,14.3%(3/21)在第5周吸收,9.5%(2/21)在第6周吸收。术后矫正视力>1.0有7例,0.3～1.0有15例,<0.3有1例。随访期间所有患者均未复发。21.7%(5/23)的患者出现角膜周边混浊,主要因病变组织范围较大,从角巩缘长入角膜周边浅基质层间,组织修复后可见角膜周边混浊,但不影响视力。4.3%(1/23)的患者在外眦角附近出现轻度睑球粘连,系结膜缝线过早脱落所致,对眼球视功能、运动和外观无影响。所有患者均未出现严重并发症。结论无蒂型结膜乳头状瘤有癌变倾向,显微手术切除联合羊膜移植是有效的治疗方法。     

氧自由基与大鼠坐骨神经非冻结性冷损伤

目的:观察大鼠坐骨神经在非冻结性低温作用后,局部氧自由基的水平及脂质过氧化产物丙二醛(malonic dialdenhyde,MDA)的含量以及形态学改变,探讨氧自由基在周围神经冷损伤中的作用。方法:80只雄性wistar大鼠随机平均分成持续低温组与间断低温组。每只大鼠一侧坐骨神经给予低温作用,另一侧作为对照。持续低温组给予坐骨神经4℃,2h;间断低温组4℃,1h,恢复体温1h后,再次4℃,1h。于冷刺激结束后即刻、4小时、1天、3天测定坐骨神经氧自由基和MDA的含量。结果:1.坐骨神经冷损伤后,以大有髓纤维变性为主,且程度随时间延长而逐渐加重,间断低温组较持续低温组的变性更显著。2.受冷侧坐骨神经局部氧自由基含量与对照侧相比:持续低温组在冷刺激结束即刻无明显变化,而间断低温组在冷刺激结束即刻就开始增加,在随后的4h,1d,3d两组都有显著增加,氧自由基含量均于1d时达高峰。而且,在低温结束即刻和3d时,间断低温组产生的氧自由基明显多于持续低温组。3.与对照侧相比,低温后即刻,持续低温组与间断低温组MDA含量均无显著变化;4h,1d,3d两组都有显著增加,两组间无显著差异。结论:非冻结性低温可以造成坐骨神经有髓纤维变性,而这种变性程度与低温后产生的氧自由基含量增加的趋势相一致,提示氧自由基是坐骨神经非冻结性损伤的因素之一。     

超高效液相色谱-静电轨道阱质谱同时筛查测定猪肉中21种磺胺类药物残留

为保障居民饮食安全,加大水产品监管力度,提升检测效率,拟开发质谱高通量筛查水产品中药物残留的检测方法。

运用有机溶剂两步提取法提取水产品中的药物残留,采用C₁₈色谱柱分离、液相色谱-静电场轨道阱高分辨质谱筛查,并通过建立的质谱数据库定性。

建立195种兽药标准品质谱数据库和检测方法,开发了通过简单、快速提取水产品中兽药残留的前处理方法,检测方法灵敏度高、定性准确,80%以上化合物的加标回收率可达70%~110%。

本方法的建立能够实现水产品中兽药残留的高通量筛查,为食品安全风险监测和监管供技术支持,应对逐年增加的水产品需求和养殖量的检测需要,并且为后续的质谱高通量检测方法开发提供理论基础。

     

Stable carbon isotopic characterization of rice vinegar protein as an intrinsic reference for discriminating the authenticity of brewed rice vinegar

Rice vinegar plays an important role in daily life. However, some unscrupulous manufacturers may deliberately add synthetic acetic acid in vinegar products to reduce fermentation time and save production costs. To protect the rights and health of consumers, vinegar authenticity must be controlled. The rice vinegar protein was used as an intrinsic reference and its stable carbon isotope ratio (δ¹³C_protein) was analyzed by elemental analyzer-isotope ratio mass spectrometry. The stable carbon isotope ratio difference between the acetic acid and the rice vinegar protein (Δδ¹³C_{acetic acid-protein}) was calculated to evaluate vinegar authenticity. Sixteen rice vinegar samples were analyzed and a stable carbon isotopic pattern of rice vinegar was established by the 95% confidence interval for Δδ¹³C_{acetic acid-protein} (0.27‰–2.10‰). An acetic acid adulteration curve of Δδ¹³C_{acetic acid-protein} was also assumed according to the data from rice vinegar samples, and its validity was confirmed by rice vinegar deliberately blended with acetic acid at different ratios (25, 50, and 75%). The Δδ¹³C_{acetic acid-protein} values of the adulterated vinegars decreased with increasing amounts blended acetic acid, but the δ¹³C_protein values did not, showing that rice vinegar protein could be used as an intrinsic reference for identifying the adulterated rice vinegar. The rice vinegar adulterated with acetic acid at higher than approximately 10% could be detected.     

Collaborative Group of the Americas on Inherited Gastrointestinal Cancer Position statement on multigene panel testing for patients with colorectal cancer and/or polyposis

Familial Cancer - Multigene panel tests for hereditary cancer syndromes are increasingly utilized in the care of colorectal cancer (CRC) and polyposis patients. However, widespread availability of...     

Cytogenetic and molecular landscape and its potential clinical significance in Hispanic CMML patients from Puerto Rico

Chronic myelomonocytic leukemia (CMML) is a clonal hematopoietic neoplasm that exhibits myelodysplastic and myeloproliferative characteristics with heterogeneous clinical and pathological features. There are limited publications on the ethnic and racial disparity of cytogenetics and genomics in CMML patients. This study aims to define the cytogenetic and molecular landscape in Hispanic CMML patients from Puerto Rico and explore its possible clinical significance. One hundred and eleven (111) Hispanic CMML patients from Puerto Rico were diagnosed in our institute from 2009 to 2018. Karyotypes were available in one hundred and seven (107) patients. Seventeen (17) patients had abnormal karyotypes (17/107, 16%). Compared to previously published data, Hispanic CMML patients in this study had significantly lower rates of overall cytogenetic abnormalities (16% vs 27–28%, p < 0.05) and trisomy 8 (2% vs 7%, p < 0.05). Among one hundred and eleven (111) Hispanic CMML patients, 40-gene myeloid molecular profile tests were performed in fifty-six (56) CMML patients. Gene mutations were identified in fifty-four (54) patients (96%). The most frequent mutated genes were: TET2, SRSF2, ASXL1, ZRSR2, DNMT3A, NRAS, CBL, and RUNX1. Twenty-nine (29) out of fifty-six (56) patients (29/56, 52%) had mutated TET2/wild type ASXL1 (muTET2/wtASXL1). Previous studies indicated that mutated ASXL1, DNMT3A, NRAS, RUNX1, and SETBP1 may associate with an unfavorable prognosis and muTET2/wtASXL1 may associate with a favorable prognosis in CMML patients. Compared to previously published data, Hispanic CMML patients from Puerto Rico in this study had significantly lower mutation rates in ASXL1 and SETBP1, and a higher rate of muTET2/wtASXL1. The findings raise the possibility of a favorable prognosis in Hispanic CMML patients.