Purification and properties of xylanase fromAureobasidium

Summary The yeast-like fungusAureobasidium is a promising source of xylanase (EC 3.2.1.8) with an exceptionally high specific activity. For enzyme production in volumes of several liters, xylose was the preferred carbon source and inducer. Xylanase in clarified cultures was concentrated by reversible adsorption to cation-exchange matrix to 5% of the initial volume, and recovered at nearly 2 million IU/1. Selective conditions permitted 97% recovery of xylanase with a 1.8-fold enrichment in specific activity, to 70% of purity. The predominant xylanase species (20 kDa) was subsequently purified to >99% of homogeneity by gel filtration chromatography. Purified enzyme exhibited an isoelectric point of 8.5, and specific activity of 2100 IU/mg under optimal conditions, determined to be pH 4.5 and 45°C. The activity of purified enzyme was specific for polymeric xylan.The mention of firm names or trade products does not imply that they are endorsed or recommended by the U.S. Dept. of Agirculture over other firms or similar products not mentioned.     

New Mechanism of Melanosomes Transport into Hair of Lambs of Different Breeds and Genotypes

By light microscopic investigation of skin and wool specimens of newborn lambs, we discovered a previously unknown mechanism for melanosomes transport in the process of dermal papilla melanocytes regular mitosis and migration into the hair shaft. This mechanism plays a great role in hair pigmentation especially in dominant (E^D/E^D) and recessive (A^a/A^a) black lambs of all investigated breeds. The rate of pigment cell mitosis, proliferation, and migration differs greatly in lambs of investigated color genotypes. In black genotypes the rate of melanocyte mitosis is very high and is approximately the same as in the hair bulb matrix cells, whereas in brown and red genotypes this rate is much lower. Melanocyte mitosis in the light red and tan groups was not found.     

经颅多普勒超声对80例偏头痛病人的检测分析

经颅多普勒超声波对８０例偏头痛病人与１１０例正常对照组血流速度进行检测．结果发现病例组血流速度异常为８７．５％。根据血流速度改变,本组分为血流速度增快型与血流速度减慢型,这有助于偏头痛的临床诊断。     

Chemical and Electron Microscopic Studies of Cattle (Bos taurus) With Four Types of Phenotypic Pigmentation

The biological behavior of the pigmentary phenotypes of four breeds of cattle has been analysed: the black pigmentation of Holstein Friesian; the red pigmentation of Limousin; the dilution in Charolais; and the postnatal disappearance of red pigmentation in Chianina. The analytic techniques included the characterization of melanins by high-performance liquid chromatography, the examination of follicular melanocytes by light microscopy, and the examination of melanosomes by electron microscopy. The black phenotype was very strongly eumelanogenic. The red phenotype in Limousin is polymorphic: individual follicular melanocytes contain both mature eumelanosomes and pheomelanosomes. Charolais and Chianina cattle exhibited a dramatic reduction in melanogenic activity, which was characterized by the almost exclusive presence of prephaoemelanosomes in Charolais and of immature premelanosomes in Chianina. In the dilute Charolais phenotype, the density of distribution of follicular melanocytes also seemed to be reduced. The genes that are responsible for these four phenotypes seem to act on the maturation, differentiation, and density of distribution of the melanosomes.     

泌尿系造影联合彩色多普勒对小儿先天性肾积水的诊断价值评估

摘要 目的：探讨泌尿系造影联合彩色多普勒对小儿先天性肾积水的诊断价值。方法：选取2018年11月～2021年11月在本院治疗的88例先天性肾积水患儿为研究对象,所有患儿均完善静脉肾盂造影及彩色多普勒超声检查,以病理诊断结果为金标准,对比两种检查方法对小儿先天性肾积水的诊断价值。结果：彩色多普勒超声检查结果显示,肾积水轻度、中度、重度患儿分别为10例、39例、39例,不同病情程度患儿比较,重度组收缩期峰值速度（PSV）、舒张期最小流速（EDV）均低于中度组和轻度组,重度组血流阻力指数（RI）高于中度组和轻度组（P<0.05）,但轻度组与中度组PSV、EDV、RI比较差异无统计学意义（P>0.05）。与病理学诊断检查结果对比,彩色多普勒超声对中度、重度先天性肾积水患儿具有较高的诊断效能,其准确度分别为90.91%、93.18%,与病理诊断kappa值分别为0.795、0.862,具有较高的一致性;但对轻度肾积水诊断效能较低,kappa值为0.629,一致性一般。静脉肾盂造影对轻度先天性肾积水患儿具有较高的诊断效能,准确度为96.59%,与病理诊断kappa值为0.824,具有较高的一致性;但对中度、重度肾积水诊断效能较低,kappa值分别为0.583、0.565,一致性一般。彩色多普勒超声联合静脉肾盂造影诊断准确率高达94.32%,明显高于两检查方法单独应用（P<0.05）。结论：不同病情程度的先天性肾积水患儿具有不同超声征象,彩色多普勒超声对中、重度肾积水患儿具有较好的诊断价值,而静脉肾盂造影诊断轻度肾积水患儿的效能较好,将二者联合可提高对先天性肾积水的诊断准确率。     

色觉异常的数学模型

色盲是一种遗传性疾病,由于色觉机理尚未研究清楚,一向不能矫治。为了解除色盲患者的苦脑,增加他们在升学、就业和职业选择中的权利,我们通过色觉过程的拓扑学研究,建立了色觉异常的突变模型;论证了色盲矫治机理;研制了色盲电脑诊断矫正检测仪。为色盲眼镜的批量生产和患者的配镜提供准确的矫正曲线。     

Necessary and sufficient conditions for Von Kries chromatic adaptation to give color constancy

Necessary and sufficient spectral conditions are presented for Von Kries chromatic adaptation to give color constancy. Von-Kries-invariant reflectance spectra are computed for illuminant spectral power distributions that are arbitrary linear combinations of the first three daylight phases. Experiments are suggested to test models of color constancy using computed spectra (either exact or approximate) within the illuminant-invariant framework.     

Application of noninvasive techniques to monitor reproductive function in a brown hyena(Hyena brunnea)

Estrus in a 10-yr-old brown hyena was described by monitoring urinary steroid metabolites. These studies were repeated the succeeding year and combined with ultrasonography, vaginal cytology, and laparoscopy to further aid in identifying natural and induced estrus. Collection of semen from a 14-yr-old male brown hyena was accomplished by electroejaculation. Use of frozen semen once during natural estrus and again during estrus induced with follicle stimulating hormone (FSH) did not result in pregnancy. Further studies with this animal indicate that stimulation with gonadotropin releasing hormone (GNRH), rather than FSH, may be the more appropriate treatment for stimulating ovulation in canids or related species. While this study did not result in conception, a significant step toward that end was realized by utilizing urinary estrogen to monitor the estrus cycle.     

甲状腺结节良恶性的彩色多普勒超声特征及其诊断价值分析

目的:研究甲状腺结节良恶性的彩色多普勒超声特征及其诊断价值。方法:选取从2016年3月~2019年2月于我院接受手术治疗的甲状腺疾病患者300例作为研究对象,均予以彩超检查,比较甲状腺良恶性结节的超声特征(主要包括直径、钙化情况、边界、回声、血流状况)。以病理活检结果为金标准,分析彩超诊断甲状腺结节良恶性的敏感性、特异性以及准确度。对比甲状腺良恶性结节的血流分型情况以及各项血流动力学参数。结果:恶性结节超声特征直径≥2 cm、有钙化、边界模糊、无回声/低回声、血流丰富人数占比均高于良性结节(均P<0.05)。以手术病理组织活检结果作为金标准,彩色多普勒超声诊断甲状腺结节的敏感性、特异性以及准确度分别为97.73%、86.11%、96.33%。甲状腺良性结节血流分型为Ⅰ型、Ⅱ型人数占比高于恶性结节,而Ⅲ型、Ⅳ型人数占比低于恶性结节(均P<0.05)。甲状腺良性结节的收缩期峰值血流速度(PSV)、阻力指数(RI)均低于恶性结节,而舒张末期血流速度(EDV)高于恶性结节(均P<0.05)。结论:彩色多普勒超声对甲状腺结节良恶性的鉴别价值较高,且具有较高的敏感性、特异性以及准确度,可为甲状腺良恶性结节的早期诊断、临床治疗提供重要的参考依据。     

彩色多普勒超声诊断不同病程老年2型糖尿病下肢血管病变的临床价值及与血清ET、NO的关系研究

摘要 目的：探讨彩色多普勒超声诊断不同病程老年2型糖尿病(T2DM)下肢血管病变(LEADDP)的临床价值及与血清内皮素(ET)、一氧化氮(NO)的关系。方法：选取我院于2019年5月~2020年4月期间收治的80例老年T2DM合并LEADDP患者为观察组,根据不同病程分为3组,<10年组30例,10~20年组33例,>20年组17例,另选取同时期我院收治的50名老年单纯T2DM患者为对照组,所有受检者均接受彩色多普勒超声检查,并检测血清ET、NO水平。对比观察组与对照组足背动脉狭窄发生率,对比不同病程患者LEADDP检出率,对比不同病程患者及对照组的动脉血管内径、动脉血流量及血清ET、NO水平,Pearson相关性分析动脉血管内径、动脉血流量与血清ET和NO水平的相关性。结果：观察组足背动脉狭窄发生率明显高于对照组(P<0.05);不同病程患者LEADDP检出率随着病程延长而增加(P<0.05);不同病程患者动脉血管内径、动脉血流量、NO水平随着病程的的延长而降低,ET水平随着病程的延长而升高(P<0.05);Pearson相关性分析显示,动脉血管内径、动脉血流量与血清ET水平呈负相关,与NO水平呈正相关(P<0.05)。结论：老年T2DM合并LEADDP患者存在明显的下肢动脉管径狭窄和血流量缓慢,病变程度随着病程延长而增加,与血清ET、NO水平有密切关系,彩色多普勒超声诊断可有效评价其病变程度。