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1.
目的:分析新生儿ABO溶血病的临床相关危险因素,提高对新生儿ABO溶血病的防治水平。方法:选择ABO血型不合的孕妇433例,根据以上产妇产前IgG抗A(B)效价、产妇妊娠次数和产妇年龄分别分组,分析各组产妇间发生新生儿溶血病(HDN)的差异及临床相关性。结果:产妇产前IgG抗A(B)效价、产妇妊娠次数和产妇年龄均与HDN发生率呈正相关性(P<0.05);IgG抗A(B)效价>256时,HDN发生率将显著提高(P<0.01);产妇妊娠次数和年龄增加后,HDN发生率将显著增加(P<0.01)。结论:夫妻血型不合的产妇进行产前保健时,应进行IgG抗A(B)效价检查,当IgG抗A(B)效价>64或IgG抗A(B)效价进行性增加时,应及早做好HDN的干预措施;通过减少意外妊娠及高龄产妇数量,可减少HDN的发生。 相似文献
2.
A french woman delivered a third full-term male baby who had a strongly positive direct antiglobulin test. During the pregnancy and after the delivery, the woman had a negative irregular antibody screening test using standard red blood cell panels. The compatibility testing between the mother's serum and the father's red blood cells was strongly positive and the antibody was identified as an anti-Wra. The baby developed a mild hyperbilirubinemia and recovered without treatment. This child was probably responsible for his mother's immunization since the two previous children were Wra negative and the mother had no history of blood transfusion or abortion. 相似文献
3.
Intervillous blood was collected from term placentae at delivery, and sera were tested for phospholipase A 2 under various experimental conditions. Enzyme activity was found to develop upon extended storage in the cold or at 37°C. The enzyme is reversibly inhibited by dithiothreitol, requires Ca ++ ions for activity, and tolerates various detergents. The apparent molecular weight is 42 kDa. In all these parameters the serum enzyme behaves similar to the 42 kDa phospholipase A 2 which we recently purified to homogeneity from thoroughly washed placental tissue. Serum phospholipase A 2 appears to be generated by proteolytic processing from a slightly larger inactive precursor which was detected immunochemically. Most likely this protein originates from fetal cells and may be released by membrane damage. We conclude that both placental serum and tissue harbour a novel type of phospholipase A 2 which is distinct from cytosolic and secretory phospholipases A 2. Preference for arachidonate containing substrate suggests a role in eicosanoid production within gestational tissues. 相似文献
4.
Four phospholipid conjugates containing the non-cytotoxic nucleosides cytidine and adenosine were prepared by condensation reactions, and their cytotoxic activity was tested in vitro against the human immortalized mammary epithelial cell H184 A 1N 4, the human mammary tumor cells MaTu and MCF7 and the B lymphoblast cell line Daudi. The synthesized compounds showed considerable activity towards H184 A 1N 4, MaTu and Daudi cells, but they were not effective against MCF7 cells. The phosphorus moiety—either monophosphate or monophosphonate—does not influence the effectiveness of the phospholipid derivatives in the case of the solid tumor cell lines and H184 A 1N 4. The leukemic Daudi cell line is strongly sensitive towards the different types of ester as well as to the type of the nucleoside component. Adenosine-5′-hexadecylphosphate proved to be the most potent compound among the substances prepared (IC 50: 9.0 μmol). 相似文献
5.
于2015—2017年小麦生长季在山东省泰安市农业科学研究院肥城试验基地进行田间试验,供试材料为‘泰山28',在150(A 1)、300(A 2)、450(A 3)、600 m 3·hm -2(A 4)4个灌水量和90(B 1)、135(B 2)、180(B 3)、225 kg·hm -2(B 4)4个施氮水平下,研究水氮组合对小麦生长发育过程中干物质积累、氮素积累、水分消耗利用、光合特性、籽粒产量等的影响。结果表明: A 3B 3条件下各生育阶段的干物质积累量和氮素积累量,成熟期籽粒干物质和氮素积累量均为最大,花前花后营养器官生产储藏干物质及氮素向籽粒的运输量最高,且与其他水氮组合处理差异显著。各氮素处理下,60~200 cm土层土壤耗水量均为A 3>A 4>A 2>A 1;A 3B 3处理下的水分利用效率和氮素利用效率高于A 3B 4、A 4B 3和A 4B 4。A 3B 3处理显著提高了开花后7~28 d的旗叶净光合速率、气孔导度和蒸腾速率,有利于小麦进行光合作用合成碳水化合物。水氮组合效应显著影响籽粒产量和产量构成,且A 3B 3处理下小麦产量最高,达到9400 kg·hm -2。综上,450 m 3·hm -2和180 kg·hm -2的水氮组合处理可以显著提高小麦干物质和氮素积累量,并促进干物质和氮素向籽粒运输,与高水肥处理相比,可以有效提高水分利用效率和氮素利用效率,有利于增强小麦旗叶的光合能力,产生更多的碳水化合物,增加籽粒产量。 相似文献
6.
为了探究秸秆还田滴灌灌水下限和秸秆还田量对温室番茄产量、品质和水分利用效率的影响,在温室内进行裂区试验。秸秆还田时间分别为1年(2018年)、2年(2017年)和3年(2016年),设置4个秸秆还田量(0、1.5×10 4、3×10 4、4.5×10 4 kg·hm -2)和4个灌水下限(50% θf、60% θf、70% θf、80% θf, θf为田间持水量),对土壤含水率、番茄产量和品质进行监测。采用方差分析、熵权法和TOPSIS法对番茄产量、品质和水分利用效率进行分析。结果表明: 番茄产量随灌水下限增大而增大,在灌水下限为80% θf时产量最大,秸秆还田第1、2和3年,最大平均产量分别为93.55、87.23和99.34 t·hm -2。水分利用效率和品质指标均随灌水下限的升高而降低。在秸秆还田第1年时,秸秆还田量为1.5×10 4 kg·hm -2时番茄平均产量达到最大值,为99.60 t·hm -2;在秸秆还田第2、3年时,秸秆还田量为4.5×10 4 kg·hm -2时番茄平均产量最大,分别为92.50和107.75 t·hm -2。番茄水分利用效率在秸秆还田第1、2年,秸秆还田量为1.5×10 4 kg·hm -2时达到最大;在秸秆还田第3年时,秸秆还田量为4.5×10 4 kg·hm -2达到最大。番茄的品质指标随秸秆还田年限和秸秆还田量增加表现出不同趋势。 相似文献
7.
Phospholipase A 2 selectively hydrolyses the ester linkage at the sn-2 position of phospholipids forming lysocompounds. This bioconversion has importance in biotechnology since lysophospholipids are strong bioemulsifiers. The aim of the present work was to study the kinetic behaviour and properties of immobilized phospholipase A 2 from bee venom adsorbed into an ion exchange support. The enzyme had high affinity for CM-Sephadex ® support and the non-covalent interaction was optimum at pH 8. The activity of immobilized phospholipase A 2 was comparatively evaluated with the soluble enzyme using a phospholipid/Triton X-100 mixed micelle as assay system. The immobilized enzyme showed high retention activity and excellent stability under storage. The activity of the immobilized system remained almost constant after several cycles of hydrolysis. Immobilized phospholipase A 2 was less sensitive to pH changes compared to soluble form. The kinetic parameters obtained ( Vmax 883.4 μmol mg −1 min −1 and a Km 12.9 mM for soluble form and Vmax = 306 μmol mg −1 min −1 and a Km = 3.9 for immobilized phospholipase A 2) were in agreement with the immobilization effect. The results obtained with CM-Sephadex ®-phospholipase A 2 system give a good framework for the development of a continuous phospholipid bioconversion process. 相似文献
8.
The biochemical nature of the feline AB blood group system was characterized by analysing red blood cells from homozygous (genotype A/A) and heterozygous (A/B) type A, type B (B/B), and type AB cats. High performance thin layer chromatography (HPTLC) of red cell gly-colipids revealed that specific neuraminic acids (NA) on gangliosides, containing ceramide dihexoside (CDH) as a backbone, correlated with the feline AB blood group antigens. Although disialogangliosides predominated, mono- and trisialogangliosides were also isolated. B cats expressed solely N-acetyl-NA (NeuNAc) on these gangliosides. In addition to expressing N-glycolyl-NA (NeuNGc) containing gangliosides, A red cells have gangliosides with only NeuNAc or mixtures of both NA. HPTLC profiles of disialogangliosides from homozygous and heterozygous A cats differed slightly in the quantity of disialogangliosides. Equal amounts of NeuNAc and NeuNGc containing disialogangliosides, as well as two intermediary forms, were recovered from AB erythrocytes. Analysing disialogangliosides from red cells belonging to 17 genetically related cats, we consistently obtained the expected disialoganglio-side profile, based on blood typing and pedigree information. SDS-PAGE of red cell membrane proteins and blotting with Triticum vulgaris, a lectin recognizing NeuNAc, revealed glycoproteins of approximately 51, 53, and 80 kD in B and AB cats but only a faint band of approximately 53 kD in A cats. By haemagglutination, Triticum vulgaris could also distinguish different blood types by specifically binding to B and AB cells. Flow cytometry showed that more anti-B bound to B cells than anti-A bound to A cells. Although AB cells had a broad range of fluorescence when compared to the profiles seen with A and B cells, the mean fluorescence with AB cells was half of that seen with A or B. These results further characterize the antigens determining the feline AB blood group system illustrating differences between A, B and AB cats, and between homozygous and heterozygous A cats. 相似文献
9.
A study of the Fe(II) complexes of P-3A (1) and (−)-desacetamido P-3A (2) abilities to cleave duplex DNA was conducted through examination of single-strand and double-strand cleavage of supercoiled φX174 RFI DNA (Form I) in the presence of O 2 to produce relaxed (Form II) and linear (Form III) DNA, respectively. Like Fe(II)-bleomycin A 2 and deglycobleomycin A 2, Fe(II)-1 and 2 effectively produced both single- and double-strand cleavage of supercoiled φX174 DNA. Unlike Fe(II)-bleomycin A 2 or deglycobleomycin A 2, Fe(II)-1 and 2 were found to cleave duplex w794 DNA with no discemible sequence selectively suggesting that the polynucleotide recognition of the C-terminus tetrapeptide S subunit of the bleomycins including the bithiazole may dominate the bleomycin A 2 DNA cleavage selectivity. 相似文献
10.
Neuromuscular transmission is decreased in aged subject. Since endogenous adenosine is a potent neuromodulator at motor nerve endings, either inhibiting via A 1 receptors or facilitating via A 2A receptors acetylcholine release, we now investigated if the tonic effect of endogenous adenosine was modified at phrenic nerve endings of aged rats. The A 2A receptor antagonist (ZM241385, 50 nM) inhibited (77 ± 9%) and the A 1 receptor antagonist (DPCPX, 50 nM) facilitated (74 ± 13%) acetylcholine release from young adult (6 weeks old) rat preparations, indicating a simultaneous tonic activation of A 2A and A 1 receptors. Tonic modulation by adenosine was unaltered in aged (24 months old) rats, since ZM241385 (50 nM) inhibited (73 ± 8%) and DPCPX (50 nM) facilitated (91 ± 20%) acetylcholine release in aged animals similarly to young rats. This indicates that, in contrast to the central nervous system where adenosine neuromodulation is modified in aged animals, the control by adenosine of phrenic nerve function is preserved in aged animals 相似文献
11.
Using a simple hemagglutination assay to determine A and B blood types, we surveyed 1,072 domestic short- and longhair (DSH/DLH) cats and 1,100 purebred cats in the United States. Data from 234 matings with 552 offspring were consistent with the hypothesis that feline blood types A and B are due to the action of two different alleles at the same gene locus and that A is completely dominant over B. Neither an AB nor an O type cat was encountered. No type B cats were found in the Siamese and related breeds or in American Shorthair and Norwegian Forest cats. Among the breeds with type B blood, the proportion was lowest in DSH/DLH cats (0.0028) and variably higher in Abyssinian, Birman, British Shorthair, Devon Rex, Himalayan, Persian, Scottish Fold, and Somali, ranging from 0.15 to 0.59. Since all type B cats have strong, naturally occurring anti-A alloantibodies, fatal neonatal isoerythrolyses occur in type A offspring of type B mothers bred to type A males. The gene frequency of the B allele and the proportion of mating at risk of neonatal isoerythrolysis were estimated in a number of breeds. In most breeds, the frequency of the B allele was less than 0.5. Since the kittens at risk for neonatal isoerythrolysis always have the genotype AB, there is constant natural selection against heterozygotes. Heterozygote disadvantage in the cat AB system represents an unusual form of negative selection, similar to that in Rh blood group incompatibility in humans. 相似文献
12.
A 1 adenosine receptors in coated vesicles have been characterized by radioligand binding and photoaffinity labelling. Saturation experiments with the antagonist 8-cyclopentyl-1,3-[ 3H]dipropyl-xanthine ([ 3H]DPCPX) gave a Kd value of 0.7 nM and a Bmax value of 82 ± 13 fmol/mg protein. For the highly A 1-selective agonist 2-chloro- N6-[ 3H]cyclopentyladenosine ([ 3H]CCPA) a Kd value of 1.7 nM and a Bmax value of 72 ± 29 fmol/mg protein was estimated. Competition of agonists for [ 3H]DPCPX binding gave a pharmacological profile with R- N6-phenylisopropyladenosine (R-PIA) > CCPA > S-PIA > 5′- N-ethylcarboxamido-adenosine (NECA), which is identical to brain membranes. The competition curves were best fitted according to a two-site model, suggesting the existence of two affinity states. GTP shifted the competition curve for CCPA to the right and only one affinity state similar to the low affinity state in the absence of GTP was detected. The photoreactive agonist 2-azido- N6- 125I-p-hydroxyphenylisopropyladenosine ([ 125I]AHPIA) specifically labelled a single protein with an apparent molecular weight of 35,000 in coated vesicles, which is identical to A 1 receptors labelled in brain membranes. Therefore, coated vesicles contain A 1 adenosine receptors with similar binding characteristics as membrane-bound receptors, including GTP-sensitive high-affinity agonist binding. Photoaffinity labelling data suggest that A 1 receptors in these vesicles are not a processed receptor form. These results confirm that A 1 receptors in coated vesicles are coupled to a G-protein, and it appears that the A 1 receptor systems in coated vesicles and in plasma membranes are identical. 相似文献
13.
植物在自然状态下释放负离子的能力很弱,施加脉冲电场可激发其释放能力。在密闭的玻璃箱中,研究紫背竹芋(Stromanthe sanguinea)、绒叶肖竹芋(Calathea zebrina)和朱顶红(Hippeastrum rutilum)在常态、脉冲电场和光照刺激下释放负离子的浓度,并观察叶片气孔特征,结果表明:(1)不同参数脉冲电场对植物释放负离子的能力影响不同,每种植物均具有高效释放负离子的最佳脉冲电场,紫背竹芋为A3B3C3(A3,U=1.5×104 V;B3,T=1.5 s;C3,?=65 ms);绒叶肖竹芋为A3B4C1(A3,U=1.5×104 V;B4,T=2.0 s;C1,?=5 ms);朱顶红为A4B4C1(A4,U=2.0×104 V;B4,T=2.0 s;C1,?=5 ms)。(2)植物体上所储存的电压越大,其释放负离子的能力越强。(3)脉冲电场作用时,植物释放负离子的能力与光照度呈正相关;无电场刺激时两者差异不显著(P0.05)。(4)植物释放负离子的能力与叶片气孔特征关系密切,脉冲电场作用下叶片气孔的开合度和气孔密度越大,其释放能力越强。 相似文献
14.
The appearance of ESR signals from Photosystem I (PS I) electron acceptors A 1 and A 0 in water or deuterium oxide suspension was followed using a low-temperature photoaccumulation technique. In deuterated samples the A 1 signal was narrowed by a factor of 0.66 compared with the control. This effect was fully reversible upon resuspension of treated samples in H 2O. The narrow ESR signal from deuterated A 1 had similar power saturation characteristics to the normal signal; however, a signal from a second component resolved by deuteration was saturated at higher microwave powers than the control. The power saturation behaviour of A −1 in un-modified reaction centres indicated that it is an anionic semiquinone in a ‘protic’ environment. Deuteration reversibly modified the relative extents of reduction of iron sulphur electron acceptors A and B such that centre B became the more stable electron acceptor. The g-value and line-width of iron sulphur centre X was not modified by deuteration although it appeared to become more efficiently reduced. These results are discussed in the light of current evidence from optical, electron spin polarisation and extraction experiments that suggest that A 1 is a quinone, probably vitamin K-1. 相似文献
15.
N 6-Substituted adenosine analogues containing cyclic hydrazines or chiral hydroxy (ar)alkyl groups, designed to interact with the S2 and S3 receptor subregions, have been synthesized and their binding to the adenosine A 1 and A 2A receptors have been investigated. Examples of both types of compounds were found to exhibit highly selective binding (K i in low nM range) to the rat A 1 receptor. 相似文献
16.
Estrogenic potency of six triterpene glycosides, Holothurin A, Holotoxin A 1, Frondoside A, Cucumarioside A 2-2 and Cauloside C, that are natural products and semi-synthesized Ginsenoside-Rh 2, were examined with yeast two-hybrid system, including expressed genes of human estrogen receptor, hER, the co-activator TIF2 and lacZ as a reporter gene. Only Ginsenoside-Rh 2 exhibited significant moderate estrogenic activity in the concentration range of 10 −7 to 10 −6 M. Its effect was approximately 30% of the activity of 17β-estradiol applied at half-effective concentration. This indicates Ginsenosides-Rh 2 is a weak phytoestrogen. The sea cucumber triterpene glycosides, Holothurin A, Holotoxin A 1, Cucumarioside A 2-2 and Frondoside A, and plant glycoside Cauloside C had no appreciable estrogenic activity. Data obtained by yeast two-hybrid assay reflect structure–activity relationship between tested compounds and 17β-estradiol. Only Ginsenoside-Rh 2 has some similarity in chemical structure with 17β-estradiol that might explain affinity of this glycoside to the hER receptor. 相似文献
17.
We have studied the evolution of acetylcholinesterase molecular forms during the embryonic development of Torpedo marmorata, in the electric organs and in the electric lobes of the central nervous system. In the early stages of development (35 mm embryos, ‘myogenic phase’ of electric organ development), globular forms of acetylcholinesterase (G 4 and G 2) are abundant in both tissues and the collagen-tailed form A 12 is already present. In the electric organs, this form accumulates rapidly after the 55–60 mm stage (‘electrogenic phase’), when synapse formation first commences. Although the molecular characteristics of the collagen-tailed forms, and particularly their aggregation properties, do not appear to change during development, their solubilization requires higher concentrations of MgCl 2, as the electrocytes mature, suggesting that they become more tightly integrated in a better organized basal lamina. The smaller collagen-tailed form A 8 shows a transient increase which coincides approximately with the maximal accumulation of A 12, suggesting that it is an intermediate in its synthesis. The accumulation of the hydrophobic G 2, which eventually becomes predominent in the adult electric organs, lags behind that of A 12. The functional significance of this important fraction of acetylcholinesterase is therefore not that of a pool of precursor for the synthesis of A 12. In the electric lobes, the tetrameric form (G 4) is abundant during development, as well as G 2 and G 1 at certain stages, but the A 12 form is predominant in the adult. 相似文献
18.
2-Chloro-5′- N-methylcarboxamidoadenosine analogues containing the (N)-methanocarba (bicyclo[3.1.0]hexane) ring system as a ribose substitute display increased selectivity as agonists of the human A 3 adenosine receptor (AR). However, the selectivity in mouse was greatly reduced due to an increased tolerance of this ring system at the mouse A 1AR. Therefore, we varied substituents at the N6 and C2 positions in search of compounds that have improved A 3AR selectivity and are species independent. An N6-methyl analogue was balanced in affinity at mouse A 1/A 3ARs, with high selectivity in comparison to the A 2AAR. Substitution of the 2-chloro atom with larger and more hydrophobic substituents, such as iodo and alkynyl groups, tended to increase the A 3AR selectivity (up to 430-fold) in mouse and preserve it in human. Extended and chemically functionalized alkynyl chains attached at the C2 position of the purine moiety preserved A 3AR selectivity more effectively than similar chains attached at the 3-position of the N6-benzyl group. 相似文献
19.
The role of protein kinase C (PKC) and calcium in the stimulation of prostaglandin D 2 (PGD 2) synthesis was investigated in primary rat astroglial cultures using the phorbol esters phorbol 12-myristate, 13-acetate (PMA), phorbol 12,13-dibutyrate (PDB) and the calcium ionophore A 23187. Both phorbol esters and the ionophore were able to stimulate PGD 2 synthesis in a concentration dependent manner. The inactive stereoisomers of PMA and PDB had no significant effect. Combinations of subthreshold concentrations of phorbol esters (10 nM PMA or 10 nM PBD) potentiated PG formation induced by 100 nM A 23187. An even more pronounced effect was observed when phorbol ester concentrations were increased to 100nM. The contribution of extra- and intracellular calcium in phorbol ester or A 23187 stimulated PGD 2 synthesis was evaluated by carrying out experiments with calcium-free media plus EGTA or with the intracellular calcium-chelating agent TMB-8. Ionophore stimulated PGD 2 release was shut down to basal values upon removal of extracellular calcium, whereas phorbol ester stimulated PGD 2 formation persisted at a reduced level. It was unabated also upon further addition of EGTA. In the presence of TMB-8, however, phorbol ester stimulated PGD 2 synthesis was completely suppressed. These data strongly suggest that PKC has an additional effect on the activation of phospholipase A 2 and subsequent prostanoid synthesis, which is independent from extracellular calcium and, thus, support the concept of more than one metabolic pathway in astrocytes that synergistically regulate phospholipase A 2 activity. 相似文献
20.
Phospholipase A 2 and acyltransferase were assayed and characterized in pure axoplasm and neural tissues of squid. Intracellular phospholipase A 2 activity was highest in giant fiber lobe and axoplasm, followed by homogenates from retinal fibers, optic lobe and fin nerve. In most preparations, exogenous calcium (5 mM) caused a slight stimulation of activity. EGTA (2 mM) was somewhat inhibitory, indicating that low levels of endogenous calcium may be required for optimum activity. Phospholipase A 2 was inhibited by 0.1 mM p-bromophenacylbromide, and was completely inactivated following heating. The level of acylCoA: lysophosphatidylcholine acyltransferase activity was higher in axoplasm and giant fiber lobe than in other neural tissues of the squid. Km (apparent) and Vmax (apparent) for oleoyl-CoA and lysophosphatidylcholine were quite similar for axoplasm and giant fiber lobe enzyme preparations. Acyltransferase activity was inactivated by heat treatment, and greatly inhibited by 0.2 mM p-chloromercuribenzoate, and to a lesser extent by 20 mM N-ethylmaleimide. Phospholipase A2 activity was present in fractions enriched in axolemmal membranes (separated from squid retinal fibers and garfish olfactory nerve) from both tissues, and it was also highly concentrated in vesicles derived from squid axoplasm. In all three preparations, phospholipase A2 activity was stimulated by Ca++ (5 mM) and inhibited by EGTA (2 mM). In addition, axoplasmic cytosol (114,000 g supernatant) retained a substantial portion of a Ca++-independent phospholipase A2, active in the presence of 2 mM EGTA. Acyltransferase activity was present at high content in both axolemma membrane rich fractions, and among subaxoplasmic fractions and axoplasmic vesicles. 相似文献
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