Effect of 1,2-dimethylhydrazine on the level of specific binding and ligand affinity to the estradiol receptor in the cytosol of uterine tissue in CBA mice

1,2-dimethylhydrazine (DMH) inducing uterine sarcomas in CBA mice was studied for its prolonged effect on the level of specific binding and affinity to the estradiol receptors in cytosol fraction of CBA mice uterine tissue. It is shown that the dissociation constant 3H-estradiol-17 beta with a receptor protein in the cytosol of uterine tissue of DMH treated mice was slightly higher than in control mice. The theoretical number of the ligand binding sites with receptor protein and the level of free binding sites of estrogen receptors were higher in DMH-treated animals than in control mice during the whole period of observation.     

Downregulation of estrogen receptor alpha and beta expression in carcinogen-induced mammary gland tumors of rats

AIM AND METHODS: The recent discovery of a new isoform of estrogen receptor (ER), ER beta, has promoted the investigation of its expression on mammary gland. This study was carried out to examine the expression of ER alpha, ER beta and proliferating cell nuclear antigen (PCNA) in the carcinogen-induced mammary tumors induced by N-methyl-N-nitrosourea (MNU) or 7,12-dimethylbenz[a]anthracene (DMBA), and to compare these expression with those of age-matched normal mammary glands. RESULTS: There was significant decrease of expression of ER alpha and ER beta in the mammary gland tumors compared with age-matched normal mammary glands (p < 0.05). In mammary gland tumors, ER alpha expression was mainly located in epithelial cells, showing intranuclear staining pattern. The decrease of ER beta expression was so distant that some tumor cells did not show any expression. There was a complete loss of ER beta expression in 50% (7/14) of MNU-induced mammary gland tumors, and 68.2% (15/22) of DMBA-induced mammary gland tumors. However, there was no difference in PCNA expression between mammary gland tumors and normal mammary glands. CONCLUSION: This study represents that the decrease of expression of ER alpha and ER beta is associated with mammary carcinogenesis, and suggests that modulation of ER alpha and ER beta may be the target for the treatment of mammary gland tumors.     

尿素通道蛋白B敲除引起小鼠大脑皮质毛细血管形态改变的体视学研究

目的：研究尿素通道蛋白B（Ureatransporter B,UT—B）敲除对小鼠大脑皮质毛细血管形态结构的影响及出现抑郁样行为的病理机制。方法采用强迫游泳实验观察野生型和UT—B基因敲除小鼠的抑郁样行为,免疫组化技术和体视学方法定量检测两型小鼠大脑皮质毛细血管总长度、总体积、总表面积、平均直径等形态学指标。结果强迫游泳实验中,野生型和UT—B基因敲除小鼠的不动时间分别为（123±19s）和（86±13s）,P=0．0012〈0．05,差异具有显著性。两型小鼠大脑皮质的体积皱缩率分别为0．53±0．04、0．51±0．07（P〉0．05）,无显著性差异。野生型小鼠和uT—B基因敲除小鼠大脑皮质毛细血管的总长度为（29．20±1．20）m和（24．00±2．45）m（P=0．093〉0．05）,总体积为（1．159±0．095）mm3和（0．855±0．060）mm3（P=0．035〈0．05）,总表面积为（6．143±0．377）cm2和（4．616±0．455）cm2（P=0．042〈0．05）,平均直径为（6．506±0．161）um和（5．564±0．118）um（P=0．016〈0．05）。结论：UT—B敲除可能导致小鼠大脑皮质毛细血管总表面积、总体积和平均直径显著下降,造成大脑血灌注量不足而引发小鼠的抑郁样行为。     

Pharmacological analysis of the contractile role of M2 and M3 muscarinic receptors in smooth muscle

Muscarinic receptors expressed on smooth muscle cells are primarily of the M(2) and M(3) subtypes. The M(3) subtype triggers contraction through an interaction with G(q) proteins to stimulate phosphoinositide hydrolysis and mobilize Ca(2+). In contrast, activation of M(2) receptors modulates contraction by preventing relaxation or by potentiating M(3) receptor-mediated contractions, which enhances heterologous desensitization. These effects can be explained by the coupling of M(2) receptors to G(i) proteins that mediate an inhibition of adenylyl cyclase and calcium-activated potassium channels. The pharmacological antagonism of a response mediated through an interaction between M(2) and M(3) receptors has been shown to resemble the profile of the directly acting receptor (M(3)), primarily, and not that of the conditional receptor (M(2)). Evidence for a contractile role of the M(2) receptor has been obtained by inactivating its signaling pathway with pertussis toxin or by measuring contractile effects of muscarinic agonists after M(3) receptors have been covalently inactivated. Under these conditions, M(2) receptors have been shown to mediate an inhibition of the relaxant effects of agents, like isoproterenol, on the contractile effects of nonmuscarinic spasmogens. Muscarinic M(2) and M(3) receptor knockout mice are useful tools for exploring interactions between these receptors in smooth muscle.     

Lack of sumatriptan-induced aortic contraction or relaxation: 5-HT1B receptor protein detected in endothelium and smooth muscle of vasa vasorum but not aorta

Since 5-HT1B receptor mRNA was reported in rat aorta, and 5-HT1B receptor activation has been linked to vascular contraction, we explored sumatriptan-induced contractility and immunohistochemical density of 5-HT1B receptor protein in rat aorta. Sumatriptan (up to 10(-4) M), a 5-HT1B/1D receptor agonist, did not contract the endothelial intact or denuded rat aorta, even in the presence of L-NAME or after induction of modest tone with PGF2 alpha (10(-6) M). Sumatriptan also did not relax aortic preparations precontract with PGF2 alpha (3 x 10(-6) M) or phenylephrine (3 x 10(-7) M). Using a polyclonal antibody directed against the 5-HT1B receptor, minimal 5-HT1B receptor protein was detected in either the endothelium or smooth muscle of the rat aorta. However, dense 5-HT1B receptor protein was found in the vascular smooth muscle of the vasa vasorum supplying the aorta. Thus, the 5-HT1B receptor mRNA detected in tissue extracts of the rat aorta most likely reflects 5-HT1B receptor expression in the arterioles of the vasa vasorum. These studies support the link between the 5-HT1B receptor and vascular contraction in that the aorta with low density of 5-HT1B receptors lacked responses to sumatriptan, an agonist thought to contract blood vessels via 5-HT1B/1D receptors. Furthermore, caution must be observed when using 5-HT1B receptor mRNA to suggest receptor protein in tissues since this RT-PCR product may be derived predominantly from small blood vessels.     

Beta 2-adrenergic receptor endocytic pathway is controlled by a saturable mechanism distinct from that of transferrin receptor.

Agonist-dependent internalization is an important phase of beta 2-adrenergic receptor (beta 2AR) regulation. Recent reports have indicated that early steps of beta 2AR endocytosis may involve mechanisms different from those which regulate the internalization of constitutively recycling receptors, such as transferrin receptor (TfR). In the present study, we addressed this issue by comparing, in the same cells, the endocytic pathway of beta 2AR with that of the TfR. Upon incubation at 15 degrees C, activated beta 2ARs accumulated in peripheral endosomes of HEK-293 cells while they were targeted to perinuclear organelles at 37 degrees C. The temperature block was not specific to beta 2ARs, since both peripheral and perinuclear beta 2AR-containing endosomes comigrated on sucrose gradients with those containing transferrin receptors and were loaded with horseradish peroxidase-coupled transferrin. Endocytosis of beta 2ARs was saturable in HEK-293 cells and did not increase upon overexpression of beta-arrestin 1. TfR endocytosis was unaffected by the simultaneous internalization of overexpressed beta 2AR, indicating that the limiting components which regulate endocytosis of these two receptors are different. In conclusion, ligand activated beta 2AR and constitutively recycling receptors, such as TfR, enter the endocytic pathway via distinct saturable mechanisms but converge in the same endosomal compartments. Our results also indicate that a still unidentified component(s) controls beta 2AR endocytosis.     

Phosphorylation of the 5-hydroxytryptamine3 (5-HT3) receptor expressed in HEK293 cells

The 5-hydroxytrptamine3 (5-HT3) receptor is a pentameric complex belonging to the family of ligand-gated ion channels. A variety of studies have suggested that phosphorylation regulates the rate of desensitisation and the size of amplitude of the receptor current. In this study we have examined the phosphorylation of the myc-tagged wild-type 5-HT3A receptor subunits from guinea-pig expressed in HEK293 cells (human embryonic kidney). Stably transfected cells were metabolically labelled with 32P-phosphoric acid. The results of immunoprecipitation and autoradiography demonstrate that both splicc variants of the 5-HT3A receptor subunit are phosphorylated in HEK293 cells. Site-specific mutagenesis revealed that phosphorylation occurs at serine 409, a potential target of protein kinase A. Thus the 5-HT3 receptor might be modulated by intracellular pathways, that allow variable 5-hydroxytryptamine action as responses to different extracellular stimuli.     

Monospecific antibodies as probes for the stoichiometry of recombinant GABA(A) receptors

GABA(A) receptors composed of alpha1beta3 gamma2 and alpha1beta3 subunits were expressed in insect Sf9 cells and solubilized in 1% Triton X100. In sucrose density gradients, [3H]-Ro15-1788 binding activity, in the case of alpha1beta3 gamma2, and [3H]-muscimol binding activity, in the case of alpha1beta3 containing receptors sedimented as a single sharp peak suggesting the formation of receptors containing a defined number of subunits. When alpha1beta3gamma2 -containing receptors were incubated with an alpha-subunit specific antibody (bd24), a single class of antibody receptor complex was formed irrespective of the receptor-antibody ratio. This is consistent with two alpha subunits cross-linked within the receptor by the antibody. Similar results were obtained using a beta-subunit specific antibody (bd17). Several classes of antibody-receptor complex were formed when receptors were pre-incubated with a gamma specific antibody (anti gamma(2) 1-15 Cys). This profile is consistent with the presence of a single gamma subunit in each complex. Experiments with alpha1beta3 subunit containing receptors and antibody bd24 produced a profile similar to that seen with alpha1beta3 gamma2 receptors, consistent with two alpha subunits per receptor complex. In this case, the anti-beta subunit antibody, bd17, produced a unique and complex profile consistent with three beta subunits per receptor. This method permits the rapid determination of subunit stoichiometries of homogeneous receptor populations     

Crystal structure of the low-temperature phase of beta Cu1.75Se analysed by electron diffraction

The beta phase of Cu1.75Se has an anti-fluorite structure, where one in eight tetrahedral copper sites are vacant. Powder X-ray diffraction measurements on Cu1.75Se showed that the beta phase transformed to a two-phase mixture of (alpha + beta) at approximately 250 K, and then the beta phase changed to a new phase at approximately 180 K. Powder X-ray and electron diffraction measurements revealed that the low-temperature phase of the beta phase has a superstructure of (2alpha(fcc) x 2alpha(fcc) x 2alpha(fcc)) type, where alpha(fcc) is the lattice parameter of the original beta phase. The superstructure was interpreted to originate from the ordering copper vacancies. The new phase was referred to as the beta' phase.     

Evidence for voltage-gated potassium channel beta-subunits with oxidoreductase motifs in human and rodent pancreatic beta cells

Voltage-gated K(+) channel alpha subunits (K(V) alpha) have been previously identified in pancreatic islet beta-cells where it has been suggested they have a role in membrane repolarization and insulin secretion. Here we report the cloning of the three mammalian K(V) beta subunits, including splice variants of these subunits, from both human and rat pancreatic islets and from the rat insulinoma cell line INS-1. Two of the splice variants, K(V) beta1a and K(V) beta3, previously reported to be neuronal tissue specific, are expressed in islets and INS-1 cells. In addition, a splice variant of K(V) beta2 that lacks two potential protein kinase C phosphorylation sites at the amino terminus is present. Immunoblot analysis suggests a high level of K(V) beta2 subunit protein in rat pancreatic islets and immunoprecipitation with anti-K(V) beta2 antibody pulls down a protein from INS-1 cells that reacts with anti-aldose reductase antibody. The K(V) beta subunits, which are attached to the cytoplasmic face of the alpha subunits and are members of the aldose reductase superfamily of NADPH oxidoreductases, may have an as yet undetermined role in the regulation of insulin secretion by the intracellular redox potential. Finally, we suggest that a systematic nomenclature for K(V) beta subunits first proposed by McCormack et al. be adopted for this family of potassium channel subunits as it corresponds with the nomenclature used for their cognate K(V) alpha subunits.     

TPA enhancement of the mutagenic and transforming action of bovine adenovirus type 3 on cultured mouse cells

The cultured 10TI/2C3H mouse cells were infected with bovine adenovirus 3(BAV-3) and treated by TPA. This combined treatment induced ouabain-resistant mutants 19 to 26 times more often than action of only BAV-3. BAV-3- and TPA-treated cells were implanted to syngenic mice. The tumours appeared 10 times more often than in the mice after implantation of only adenovirus treated cells.     

The bradykinin B2 receptor couples less efficiently than the angiotensin AT1 receptor to the G protein Gq in transiently transfected COS-7 cells

The purpose of this study was to compare the efficiency of two different Gq protein-coupled receptors (AT1 receptor for angiotensin II and B2 receptor for bradykinin) to activate phospholipase C (PLC). When the receptors were expressed at a similar level of 0.5 pmol/mg of protein, inositol trisphosphate (IP) accumulation elicited by AT1 receptor was four times higher than that elicited by B2 receptor. Genistein and pertussis toxin did not modify AT1 receptor- or B2 receptor-induced IP accumulation. These results indicate that in COS-7 cells, the two receptors activate PLC beta through G proteins of the Gq family. AT1 or B2 receptors were co-expressed with the alpha subunit of either Gq or G11. Both alpha subunits potentiated to the same extent AT1 receptor-induced IP accumulation. alpha 11 was also as efficient as alpha q to potentiate B2 receptor-induced response. Interestingly, however, the potentiating effect of alpha q and alpha 11 was more important (by 5-fold) on AT1 receptor-mediated response than on B2 receptor-mediated response. These results demonstrate that the extent of activation of PLC beta by different Gq-coupled receptors depends on the level of expression of these receptors and on their coupling efficiency. These are important parameters that determine the relative contribution of specific hormones to different biological processes.     

高导电性BaRuO_3薄膜及其脉冲激光沉积

钌酸盐是典型的ＡＢＯ３型过渡金属氧化物，具有金属导电性，其薄膜可作为电极材料用于集成铁电等器件中。分析了ＢａＲｕＯ３的钙钛矿晶体结构和导电机制，并利用ＡｒＦ准分子脉冲激光沉积（ＰＬＤ）技术，结合后续退火处理，在Ｓｉ（１００）衬底上生长出具有（１１０）取向、室温电阻率约１０－２～１０－３Ω·ｃｍ的ＢａＲｕＯ３高导电性薄膜，俄歇能谱（ＡＥＳ）和Ｒｕｔｈｅｒｆｏｒｄ背散射谱（ＲＢＳ）分析表明：薄膜ＢａＲｕＯ３的纯度高、成分均匀性好，ＢａＲｕＯ３／Ｓｉ界面存在扩散过渡层。     

A Bayes sensitivity analysis when using the beta distribution as aprior

Results that illustrate the determination of the parameters of a beta prior distribution when either the mean and one percentile or two percentiles are given are presented. Further results show how sensitive the parameters of the beta prior are to errors in the given values. The sensitivity of the probability distribution of the reliability of a system to errors in either the given mean and percentile or the given percentiles of the component beta priors is studied. Included in the study are several systems, ranging from simple ones that occur as subsystems of real systems up to a real type of system consisting of 74 components     

基于移动智能终端的便携式眼底图像检测仪

提出了一种便携式眼底图像检测系统,连接在移动智能设备上对眼底图像进行拍摄、存储、显示和解析。采用紧凑精密的光路结构开发了基于Android的图像处理与解析软件,并通过智能终端自带的远程消息发送软件,可将眼底图像远程传送给专业医生进行临床诊断。仿真结果表明,照明均匀性超过85%,杂散光在2%内。实验结果表明,该检测仪光学系统的视场为45°、工作距离为30 mm、总长度＜180 mm,可实现眼光焦度补偿范围为-10～+5 m-1,成像清晰,畸变＜6%。实现了对眼底检查的远程移动医疗。     

Natural killer activity of splenocytes of C3HA mice in the early period after transplantation of hepatoma 22a cells

It is shown that during 10 days after transplantation of syngenic 22a hepatoma cells to C3HA mice, wave-like fluctuations of the natural killer cell (NK) activity of splenocytes take place. Xenogenic (K-562) and allogenic (AC-1) cells are used as target cells in the 18th hour 3H-uridine cytotoxic test. A significant increase in the NK-activity on the 2nd-3rd and 7-9th days after tumour cells transplantation is observed. Elimination of adherent cells from suspension of splenocytes lead to an increase in the NK-activity especially on the 7th-9th days.     

The extinction ratio in optical two-guide-coupler Delta beta switches with asymmetric detuning

Two-guide asymmetrically detuned Delta beta optical coupler switches with two equal-length sections that operate as on-off switches are examined by means of the exact eigenmodes of a slab waveguide model of the coupler. Two input/output configurations are analyzed, namely (1) where a single output guide is connected to the same guide of the coupler as the input guide, and (2) where a single output guide is connected to the coupled guide. For both cases, ideal switching, i.e. complete extinction in the off state, can be obtained in the two-section Delta beta coupler over a wide range of coupler lengths. The results differ from those of conventional coupled-mode theory in that when the two sections of the coupler are antisymmetrically detuned, i.e. delta = delta /sub 1/=- delta /sub 2/, complete extinction can be obtained only in a few special cases.<>     

Immunocytochemical study of alpha 1 and beta 2/3 subunits of GABAA receptors in freehand isolated vestibular Deiters' neurons

Vestibular Deiters' neurons have been isolated from bovine brain by the Hydén's freehand dissection technique and challenged with monoclonal antibodies directed toward the alpha 1 and beta 2/3 subunits of the GABAA receptors. Subsequent challenge with fluorescent secondary antibodies and confocal microscopy allowed the study of the cellular distribution of such subunits. In Deiters' neurons the beta 2/3 subunit displayed a clear presence all along the cell body profile and the initial parts of the dendrites. The alpha 1 subunit was found highly present all over the cell interior except the nuclear profiles. The strong presence inside the cells possibly masked its presence on the plasma membrane. However, in part of the cells studied a distinct presence on the plasma membrane was evident. This subunit was visualized also all along the long dendrites of these neurons. The approach we describe here, involving freehand isolated mature neurons from adult animals, may allow a better characterization of the tridimensional distribution of different types of neuronal GABAA receptors in the respect of the approach with brain slices.     

Evolutionary feature synthesis for object recognition

Features represent the characteristics of objects and selecting or synthesizing effective composite features are the key to the performance of object recognition. In this paper, we propose a coevolutionary genetic programming (CGP) approach to learn composite features for object recognition. The knowledge about the problem domain is incorporated in primitive features that are used in the synthesis of composite features by CGP using domain-independent primitive operators. The motivation for using CGP is to overcome the limitations of human experts who consider only a small number of conventional combinations of primitive features during synthesis. CGP, on the other hand, can try a very large number of unconventional combinations and these unconventional combinations yield exceptionally good results in some cases. Our experimental results with real synthetic aperture radar (SAR) images show that CGP can discover good composite features to distinguish objects from clutter and to distinguish among objects belonging to several classes. The comparison with other classical classification algorithms is favorable to the CGP-based approach proposed in this paper.