无界流场中单根纤维管膜外表面平均传质系数对流场的依赖性

影响透析器整体传质性能的关键表征参数是纤维管外表面对流传质系数,流场大小对表面传质系数的影响已经有研究报道,本文主要研究流场方向对表面传质系数的影响.以无界流场中单根纤维管传质过程为物理模型,计算不同流动方向下无界流场中单根纤维管表面的平均传质系数;考察了周围纤维管有界流场的影响.计算结果显示,流场垂直纤维管表面时平均传质系数最大,随着流动角度增加,平均传质系数逐渐下降.平行于纤维管轴向时平均传质系数最小,约为最大传质系数的1/3.因此,就纤维管表面传质系数而言,局部流场速度方向与大小的影响都不能忽略,即当用多孔介质模型简化和优化透析器结构时,所采用的局部表面传质系数依赖于局部流场大小和方向.     

聚醚砜中空纤维血液透析膜的制备与透析性能初步评价

采用干-湿相转化法制备聚醚砜(polyethersulfone,PES)中空纤维血液透析膜,讨论了制膜液中聚乙二醇(polyethylene glycols,PEG)添加剂含量、壁厚、内径对膜物理和机械性能的影响;并用牛血清白蛋白(bovine serumalbumin,BSA)、溶菌酶和尿素配制成模拟液代替血液进行血液透析实验,测试膜结构和操作条件对透析性能的影响。结果表明,制膜液PEG添加剂含量为27.6wt%时,制得的PES膜透析性能略低于PEG为24.1wt%时,但中空纤维丝可纺性和机械性能明显提高。使用PES膜面积为0.2 m2的透析器,通过减小膜的壁厚或减小中空纤维丝的内径,PES膜对较难去除的中分子毒素溶菌酶的清除率可以高达64.2%,对小分子尿素的清除率高达89.4%,同时成功截留98%以上的大分子蛋白质BSA。增大透析器内的膜面积、适当加快模拟液或透析液的流速可以提高透析效率。此外,与进口PS膜透析器的透析性能比较结果显示,PES膜具有更高的单位膜面积的透析效率,值得继续展开血液相容性等深入研究。     

费森尤斯4008型血液透析机漏血报警故障分析

0引言透析漏血传感器是费森尤斯4008型血液透析机的重要组成部分,在血液透析治疗过程中透析器破膜出现血液溢出或气泡时,它会立即报警,包括漏血真报警和漏血误报警。本文将对该型号血液透析机漏血报警常见故障进行分析以供同行参考。1漏血真报警1.1报警原因(1)透析器破膜:当静脉端堵塞发生后,血液透析管路部分静脉压、跨膜压会急剧升高,超过透析器膜压力后使透析器破膜;复用时消毒液浓度过大,透析膜损伤,使透析器破膜。(2)透析器质量不合格、透析器重复使用次数过多、复用时未做透析器破膜检测,导致使用时出现漏血报警。(3)透析液中有空气、除气不良、短时间内超滤量过大、漏血感应器被废液污染或发生故障时易出现误报警。     

JAK-1型人工肾的试制

作者研制一种可携带的小型化人工肾,其组成是:1)血液透析器;2)透析液供给装置;3)透析液再生用吸附剂;4)各种监视装置;5)电源等五部分。血液透析器是用扁平型中空纤维所制,透析液可一次供给二升,经吸附剂(活性炭及氧化铝)250克吸附以后再循环使用。监视装置可观测血流量、回路的正压、透析液的温度以及浓度等。血液透析器的外形大小为85毫米×210毫米×40毫米,重量470克(包括血液的驱动部分),透析膜的纤维为内径200微米,厚11微米的铜氨膜,其有效透析面积1米~2。     

脉动流实验装置研究

为了进一步研究脉动流的压力和流量分布规律,本文设计了一套可以产生脉动流,并可进行弹性管道内流体压力和流量测量的实验装置。首先参照工业用液压系统的原理,利用单片机89S51控制电磁阀的开关频率,得到入口流脉动频率;再利用LabVIEW编写采集程序,得到管道内流体压力及流量的测量数据。通过初步测试及数据结果分析得出压力与流量的不同分布特征,即入口流脉动频率增加时,流量增加,管壁受到的压力也增大;对于相同的入口脉动频率,随着与动力源距离的增加,压力减小,流量没有显著变化。本文测试结果将为进一步的临床实验提供有效实验依据。     

人工肾血液透析过程中反渗透现象及其临界尺度的研究

建立了一个能够初步描述人工肾血液—透析器流场的数学模型。用数值计算的方法模拟了透析器中的流体流动 ,并在实际的流动参数和物性参数范围内 ,对可能出现的反渗透现象作了研究和分析。计算结果表明 ,反渗透出现在血液流动的后期 ,且反渗透出现的临界尺度和流场的流动参数以及膜的物性参数之间存在着一定的关系。此外 ,还研究了反渗透对血液浓度的影响。     

颈动脉血液动力学的数值模拟

背景:由于颈动脉个体差异的多样性,血流量的不同等,因此建立人体真实动脉模型有其自身的局限性。目的:分析不同颈总动脉脉动入口波形和内外颈动脉出口流量分配比对颈动脉血液动力学的影响。方法:建立标准性颈动脉音叉式分叉TH-AHCB三维模型。采用不同脉动入口条件和出口流量分配比,利用ANSYS流体分析软件数值模拟颈动脉分叉管内流场,计算血液动力学参数,包括速度、壁面剪切力(WSS)等,结合数值计算结果,不同角度分析其与动脉粥样硬化的关系。结果与结论:内外颈动脉的出口流量分配比的差异对分叉管内的流场影响很大;颈总动脉入口脉动波形的变化不仅改变血液动力学参数(速度、压力、壁面切应力等)的差值,同时还会导致力学机制作用的范围改变。     

一氧化氮抑制剂对腹膜透析大鼠腹膜形态及表面层的影响

目的:探讨高糖透析液对大鼠腹膜巨噬细胞一氧化氮(NO)的产生、诱导型一氧化氮合酶(iNOS)的表达和腹膜透析通透性的影响以及NO抑制剂的保护作用。方法: 培养生理盐水、1.5％和4.25％葡萄糖透析液透析下的大鼠腹腔内的巨噬细胞, 检测细胞培养上清液NO的浓度和巨噬细胞iNOS的表达, 并观察1.5％及4.25％葡萄糖透析液和NO抑制剂透析下大鼠的液体超滤量和腹膜形态的变化。结果:大鼠腹腔内巨噬细胞NO的产生随透析液中葡萄糖含量增加而增加;腹腔巨噬细胞iNOS的表达, 葡萄糖透析组明显高于生理盐水组;NO抑制剂对光镜下腹膜形态无影响, 但明显减轻4.25%葡萄糖透析液对超滤量和腹膜表面层的减少作用。结论:一氧化氮抑制剂可明显改善高糖透析大鼠的腹膜通透性, 并减轻高糖对腹膜表面层的损伤。     

实体肿瘤中淋巴分布对流体流动的影响

实体肿瘤结构复杂,内部血管和淋巴分布均有明显的不均匀性.本文考虑毛细血管滤出作用和淋巴吸收作用,建立球对称实体肿瘤内流体动力学模型,考察肿瘤内流体的流动.根据Starling定律建立跨毛细血管壁输运模型,间质中流动由Darcy定律决定,由此得到离体肿瘤内部压强和速度分布的基本方程组.对跨淋巴管壁输运的不同假设,引入幂函数、三次多项式、反正切等形式的毛细血管密度分布和淋巴管密度分布,反映肿瘤内血管和淋巴的不均匀分布,讨论它们对流体流动的影响.结果表明淋巴的存在将降低肿瘤内部压强,并有可能在局部提高对流,但并不能从本质上改善肿瘤内部的高压强和低压强梯度引起的低对流.这可以为揭示淋巴对肿瘤的化学药物治疗的影响给出提示.     

动脉粥样硬化斑块失稳破裂简化模型的高阶动力学研究

研究了动脉粥样硬化斑块失稳破裂模型的高阶简化形式,证明了纤维帽运动过程中存在着临界频率,当动脉内脉动压力频率低于该临界值时,纤维帽将可能发生参数共振;数值模拟结果表明,纤维帽内外压力差脉动频率的微小变化有可能导致纤维帽运动形式产生质的改变;研究了不同心血管参数变化与斑块破裂间的联系.     

Studien zur humoralen Regulation des erythropoetischen Proliferationsspeichers beim Menschen

Zusammenfassung Die Beeinflussung der Erythroblasten-Proliferation durch das Mikromilieu wurde in vitro mittels Auswertung durch Differential- und Mitosezählungen und Signifikanzberechnung vieler Versuchsreihen auch unter verschiedenen pathologischen Bedingungen getestet.Sowohl die Mitosehäufigkeit wie die Ausreifung waren positiv mit dem Erythropoetingehalt des Medium korreliert. Der Effekt wurde durch Folsäure, Ätiocholanolon und cAMP verstärkt. Cobalt stimulierte ebenso wie Testosteron und Methenolon in vitro unabhängig von der Erythropoetinkonzentration im Medium die Erythroblastenproliferation. Ein vermindertes Eisenangebot störte die endgültige Ausreifung der Erythroblasten zu Retikulozyten und bewirkte dadurch eine Ineffektivität der Erythorpoese. Anhaltspunkte für ein Erythrozyten-Chalon oder einen Erythropoetinhemmkörper ließen sich aus unserem Versuchsansatz nicht gewinnen, weil er die Transformation der pluripotenten in die erythropoetin-sensible Stammzelle nicht einschließt. Als Nebenbefund ergab sich eine Stimulation des granulozytopoetischen Proliferationsspeichers durch Serumzusatz zum Medium von Patienten nach akutem Blutverlust und bei Polycythämia vera.Unterstützt durch die Deutsche Forschungsgemeinschaft     

HLA study in Amerindian Bolivia La Paz Aymaras

Aymara people has been a relatively homogeneous group since Spanish Conquest by 1,532 CE, even if previously represented a group of various cultural defined populations who gave rise to them. They were and are established in Andean Altiplano around Titikaka Lake (Bolivia, Peru), Argentina and Chile neighborhood, speak Aymara language and have been maintained after Europeans arrival at a lower social status than Quechua (Inca) speaking people. However, both Aymara and Quechua populations acknowledge Titikaka Lake as center of their origins; both languages are also related. Specific high frequencies of HLA-A*02, -A*24 and -A*68, HLA-B*35, -B*39 and -B*48, HLA-DRB1*08:02, -DRB1*09:01, and -DRB1*14:02, and HLA-DQB1*04:02, -DQB1*03:02 and -DQB1*03:01 alleles are found in Aymaras and HLA class II haplotypes common to Andean Amerindians (DRB1*08:02-DQB1*04:02 and DRB1*04:03-DQB1*03:02), like Quechua, Aymara, Uros, Lamas and Mapuche are also found in Easter and other Pacific Islands. Giant human head stone statues at Tiwanaku (Titikaka Lake, Bolivia) are also found at Easter Island. Thus, it is possible a gene and cultural flow between Andean Amerindians and Easter and other Pacific Islands, as it was demonstrated by Thor Heyerdahl in his Kon-Tiki expedition which reached Pacific Islands sailing from El Callao Harbour (Lima, Peru).     

Lipid composition of metacestodes of Taenia taeniaeformis and lipid changes during growth

A lipid analysis was performed on developing metacestodes of Taenia taeniaeformis removed from the livers of rats at times varying from 3 to 35 weeks post infection. Lipid accounted for 7–21% of the dry weight of the parasites. The highest proportions were found at the earlier stages. The distribution was as follows; neutral lipid 27–45%; glycolipid 5–11%; and phospholipid 50–61%. The major neutral lipid was cholesterol, and minor neutral lipids were sterol esters, triglycerides, diglycerides and monoglycerides. Hydrocarbons were present throughout development, but in the highest amounts at the earlier stages. Five different glycolipids were found, all of which were identified as glycosphingolipids. An increase in the proportion of more complex glycolipids was noted as parasites grew older. Ten different phospholipids were identified, with the major components being phosphatidylcholine, phosphatidylethanolamine, and phosphatidylserine. Other phospholipids were: lysophosphatides, phosphatidylinositol, phosphatidic acid, diphosphatidylglycerol, sphingomyelin, and an unknown phospholipid component. Changes in the relative amounts of the two major phospholipids were found when the early and late stages were compared. Two lipids found throughout development were identified as glycosylated dolichol phosphates, and they comprised between 1 and 3% of the total phospholipid fraction. Nineteen fatty acids were detected, and the fatty acid distribution for each lipid class at each stage was determined. Seven major fatty acids were common to each. These were: hexadecanoic, octadecanoic, oleic, linoleic, arachidonic, docosanoic, and docosahexaenoic.     

Simple Serological Assays for Detecting Rice Tungro Viruses

An attempt was made to produce sensitive and specific polyclonal antisera against the viruses causing rice tungro disease, and to assess their potential for use in simple diagnostic tests. Using a multiple, sequential injection procedure, seven batches of polyclonal antisera against rice tungro bacilliform virus (RTBV) and rice tungro spherical virus (RTSV) were produced. These were characterized for their sensitivity and specificity using ring-interface precipitin test and double antibody sandwich (DAS) ELISA. Thirty-one weeks after the first immunization, antiserum batch B6b for RTBV showed the highest ring interface titer (DEP = 1:1920). For RTSV, batches S3, S4b and S5b all had similar titres (DEP = 1:640). In DAS-ELISA, however, significant differences among purified antisera (IgG) batches were observed only at IgG dilution of 10^-3. At that dilution, IgGB4b showed the greatest sensitivity, while IgGS3 showed greatest sensitivity for RTSV. When all IgG batches were tested against 11 tungro field isolates (dual RTBV-RTSV infections) at sample dilution of 1:10, IgGB4b and IgGB6b for RTBV and IgGS3 and IgGS6b for RTSV performed equally well. However, after cross adsorption with healthy plant extracts in a specially prepared healthy plant-Sepharose affinity column, only IgGB6b could be used specifically to detect RTBV in a simple tissue-print assay.     

Is it worthy to take full-course immunotherapy for allergic rhinitis? About efficacy biomarker of allergen immunotherapy

Nowadays, people pay more attention to biomarkers that can predict clinical efficacy of immunotherapy for allergic rhinitis. As the only recognized aetiological treatment, the efficacy of allergen immunotherapy (AIT) has been proved by many studies. However, treatment success depends on compliance and persistence greatly, which can be impaired by the lengthy duration of AIT and socioeconomic status of patients. Besides, ineffectiveness is another factor that accounts for non-adherence. If the clinical efficacy can be predicted in the early stage of immunotherapy, it can help patients choose appropriate treatment plans, increase patient compliance and optimize the allocation of medical resources. This paper mainly focuses on five candidate biomarkers, the sIgE/tIgE ratio before treatment, serum inhibitory activity for IgE, decreased basophil activation, upregulation of Tregs and tolerogenic DCs, reviews the time when potential biomarkers can predict or monitor the efficacy of AIT, discusses the reason why these indicators could serve as efficacy biomarkers and interactions among potential biomarkers.     

Neurotransmitter signaling pathways required for normal development in Xenopus laevis embryos: a pharmacological survey screen

Neurotransmitters are not only involved in brain function but are also important signaling molecules for many diverse cell types. Neurotransmitters are widely conserved, from evolutionarily ancient organisms lacking nervous systems through man. Here, results are reported from a loss‐ and gain‐of‐function survey, using pharmacological modulators of several neurotransmitter pathways to examine possible roles for these pathways in normal embryogenesis. Applying reagents targeting the glutamatergic, adrenergic and dopaminergic pathways to embryos of Xenopus laevis from gastrulation to organogenesis stages, we observed and quantified numerous malformations, including craniofacial defects, hyperpigmentation, muscle mispatterning and miscoiling of the gut. These data implicate several key neurotransmitters in new embryonic patterning roles, reveal novel earlier stages for processes involved in eye development, suggest new targets for subsequent molecular‐genetic investigation, and highlight the necessity for in‐depth toxicology studies of psychoactive compounds to which human embryos might be exposed during pregnancy.     

Uncombable Hair (cheveux incoiffables, pili trianguli et canaliculi) Syndrome: Brief Review and Role of Scanning Electron Microscopy in Diagnosis

Uncombable hair syndrome was first described some 3 decades ago as "cheveux incoiffables" and is also known as spun-glass hair and pili trianguli et canaliculi. Both inherited (autosomal dominant and recessive with variable levels of penetrance) and sporadic forms of uncombable hair syndrome have been described, both being characterized by scalp hair that is impossible to comb due to the haphazard arrangement of the hair bundles. A characteristic morphologic feature of hair in this syndrome is a triangular to reniform to heart shape on cross-sections, and a groove, canal or flattening along the entire length of the hair in at least 50%of hairs examined by scanning electron microscopy. Most individuals are affected early in childhood and the hair takeson a spun-glassappearance with the hair becoming dry, curly, glossy, lighter in color, and progressively uncombable. Only the scalp hair is affected. Several conditions are associated with uncombable hair, such as ectodermal dysplasia, retinal dysplasia/ pigmentary dystrophy, juvenile cataract, digit abnormalities, tooth enamel anomalies, oligodontia, and phalangoepiphyseal dysplasia. Other syndromes with hair abnormalities may also mimic uncombable hair syndrome clinically and these include, Rapp-Hodgkin ectodermal dysplasia; loose anagen hair syndrome; ectodermal dysplasia, ectrodatyly, cleft lip/ palate (EEC) syndrome; and familial tricho-odonto-onchyial ectodermal dysplasia with syndactyly. Unlike other conditions with an uncombable hair component, uncombable hair syndrome alone (cheveux incoiffables, pili trianguli etcanaliculi) is not associated with physical, neurologic, or mental abnormalities. In most cases of uncombable hair syndrome, the hair is grossly abnormal in infancy and early childhood, but may have improved manageability later in life. Scanning electron microscopy of hair samples provides definitive evidence for diagnosis of clinically suspected uncombable hair syndrome and eliminates other hair abnormalities from the differential diagnosis.     

A comparative study of cholinergic systems of the neocortex and hippocampus in rats with low and high resistance to hypoxia

Synaptic structures in the neocortex and hippocampus of the intact brain were compared between rats with low and high resistance to hypobaric hypoxia. Activities of choline acetyltransferase, acetylcholinesterase, Na,K-ATPase, and the portion of protein in the light and heavy synaptosome fractions and subfractions were measured. A discrepancy in cholinergic metabolism molecular mechanisms between high and low resistance animals have been found in the heavy somatosoma fraction from the neocortex. Activities of choline acetyltransferase, acetylcholinesterase, and Na,K-ATPase in the synaptolemmal subfraction of low resistant rats were much lower than in high resistant rats. This implies a less effective synaptic transmission in proper cholinergic neurons in the low resistance animals and, therefore, specifically changed neuron functioning in the circulation control. No differences in the cholinergic components of either neocortical light synaptosome fraction or hippocampal light and heavy synaptosome fractions were found between low and high resistance rats. Translated fromByulleten' Eksperimental'noi Biologii I Meditsiny, Vol. 125, No. 5, pp. 521–525, May, 1998     

BSACI guideline for the diagnosis and management of cow's milk allergy

This guideline advises on the management of patients with cow's milk allergy. Cow's milk allergy presents in the first year of life with estimated population prevalence between 2% and 3%. The clinical manifestations of cow's milk allergy are very variable in type and severity making it the most difficult food allergy to diagnose. A careful age‐ and disease‐specific history with relevant allergy tests including detection of milk‐specific IgE (by skin prick test or serum assay), diagnostic elimination diet, and oral challenge will aid in diagnosis in most cases. Treatment is advice on cow's milk avoidance and suitable substitute milks. Cow's milk allergy often resolves. Reintroduction can be achieved by the graded exposure, either at home or supervised in hospital depending on severity, using a milk ladder. Where cow's milk allergy persists, novel treatment options may include oral tolerance induction, although most authors do not currently recommend it for routine clinical practice. Cow's milk allergy must be distinguished from primary lactose intolerance. This guideline was prepared by the Standards of Care Committee (SOCC) of the British Society for Allergy and Clinical Immunology (BSACI) and is intended for clinicians in secondary and tertiary care. The recommendations are evidence based, but where evidence is lacking the panel of experts in the committee reached consensus. Grades of recommendation are shown throughout. The document encompasses epidemiology, natural history, clinical presentations, diagnosis, and treatment.