Estrone Sulfate: Production Rate and Metabolism in Man

Since estrone sulfate (E(1)S) is present at high concentration in plasma, we have examined the parameters of the plasma estrone, estradiol, E(1)S system. The metabolic clearance rate of E(1)S was 157 liter/day (range 70-292) in men and women. Estimated plasma production rates of E(1)S were (mugrams per day): men, 77; women, early follicular phase, 95; women, early luteal phase, 182. The conversion of plasma estrone and estradiol to E(1)S was measured and from these data and the metabolic clearance rates of the estrogens, the transfer factors were rho(E) (1) (E) (1) (S) = 0.54 and rho(E) (2) (E) (1) (S) = 0.65. Using average production rates, all plasma E(1)S could be shown to be derived from plasma estrone and estradiol.The conversion of plasma E(1)S to plasma estrone and estradiol was studied. The calculated transfer factors were: rho(E) (1) (SE) (1) = 0.21, rho(E) (1) (SE) (2) = 0.014. Essentially, similar data were obtained when E(1)S was given by mouth to two subjects.WE CONCLUDE: (a) E(1)S is a major circulating plasma estrogen and has a long plasma half-life; (b) the large contributions of estrone and estradiol to plasma E(1)S are more than sufficient to account for all the circulating plasma E(1)S.     

轻型β-珠蛋白生成障碍性贫血患者β-珠蛋白基因( AC)n(AT)x Ty多态性分析

目的 探讨轻型β-珠蛋白生成障碍性贫血患者β-珠蛋白基因(AC)n(AT)xTy多态性与其基因突变的相关性.方法 选取2009年2月至2010年7月深圳市宝安区人民医院89例已知基因突变类型的轻型β-珠蛋白生成障碍性贫血患者和110名中国汉族人群健康对照者.抽取所有个体外周静脉血,抽提基因组DNA,通过聚合酶链反应扩增β-珠蛋白基因BP1蛋白结合区序列,经DNA测序确定(AC)n(AT)xTy序列的多态性,分析(AC)n(AT)xTy多态性与其基因突变的关系.轻型β-珠蛋白生成障碍性贫血患者和健康对照者间(AC)n(AT)xTy多态性单倍型频率的比较,以及同一单倍型患者的不同突变类型发生率间的比较采用x2检验.结果 在轻型β-珠蛋白生成障碍性贫血患者的β-珠蛋白基因BP1蛋白结合区存在9种(AC)n(AT)xTy多态性序列,分别是(AC)2(AT)7T7、(AC)2 (AT)8T5、(AC)3 (AT)7T5、(AC)2 (AT)9T5、(AC)2 (AT)8T9、(AC)3 (AT)8T5、(AC)2(AT)10T3、(AC)2(AT)7T5和(AC)2(AT) 11T3,其中(AC)2 (AT)7T7和(AC)2(AT)8T5是常见单倍型.轻型β-珠蛋白生成障碍性贫血患者的(AC)2(AT)7T7、(AC)3 (AT)7T5和(AC)2(AT)8T9单倍型频率分别为38.8％( 69/178)、11.8％( 21/178)、9.0％( 16/178),显著高于健康对照组的24.1％(53/220)、5.4％ (12/220)、3.2％ (7/220),差异有统计学意义(x2=9.966、4.371、6.093,P＜0.05);(AC)2 (AT)9T5单倍型频率为10.1％(18/178),显著低于健康对照组的33.2％ (73/220),差异有统计学意义(x2=29.691,P＜0.01);而(AC)2 (AT)8T5单倍型频率在患者组和健康对照组分别为25.3％ (45/178)和29.1％ (64/220),差异无统计学意义(x2 =0.718,P＞0.05).在(AC)2 (AT)7T7单倍型患者中,codon41/42(-TTCT)和IVS-II-654(C→T)的突变率分别为59％( 10/17)和29％(5/17),差异无统计学意义(x2=2.982,P＞0.05);在(AC)2( AT)8T5单倍型患者中,codon41/42(-TTCT)和IVS-Ⅱ-654(C→T)的突变率分别为29％(4/14)和57％ (8/14),差异无统计学意义(x2=2.333,P＞0.05).结论 β-珠蛋白基因BP1蛋白结合区的(AC)2 (AT) 7T7、(AC)3 (AT)7T5和(AC)2(AT)8T9单倍型与轻型β-珠蛋白生成障碍性贫血存在连锁不平衡.在轻型β-珠蛋白生成障碍性贫血患者中,携带( AC)2( AT)7T7单倍型和(AC)2(AT) 8T5单倍型患者的主要致病突变分别为codon41/42 (-TTCT)和IVS-II-654(C→T).     

Spinal EP receptors mediating prostaglandin E2-induced mechanical hyperalgesia, thermal hyperalgesia, and touch-evoked allodynia in rats.

Intrathecal administration of prostaglandin E(2) (PGE(2)) produces mechanical hyperalgesia, thermal hyperalgesia, and touch-evoked allodynia in rats. Experiments were conducted to examine the effects of intrathecal administration of relatively selective PGE(2) receptor (EP receptor) agonists to establish which spinal EP receptors mediate these behavioral effects of spinally administered PGE(2). Administration of either sulprostone (EP(3) receptor agonist) or PGE(1) alcohol (EP(4) receptor agonist) produced marked mechanical and thermal hyperalgesia and touch-evoked allodynia. Neither 17-phenyl trinor PGE(2) (EP(1) receptor agonist) nor butaprost (EP(2) receptor agonist) produced any significant changes in behavioral response thresholds to mechanical or thermal stimuli. However, 17-phenyl trinor PGE(2) (EP(1) receptor agonist) did produce marked touch-evoked allodynia. These data suggest that in rats activation of spinal EP(3) and EP(4) receptors by PGE(2) is important for development of both mechanical and thermal hyperalgesia as well as for touch-evoked allodynia. PGE(2)-induced allodynia also appears to involve activation of spinal EP(1) receptors.     

High frequency oscillatory ventilation for respiratory failure due to RSV bronchiolitis

OBJECTIVE: To describe the time course of high frequency oscillatory ventilation (HFOV) in respiratory syncytial virus (RSV) bronchiolitis. DESIGN: Retrospective charts review. SETTING: A tertiary paediatric intensive care unit. PATIENTS AND PARTICIPANTS: Infants with respiratory failure due to RSV infection. INTERVENTION: HFOV. MEASUREMENTS AND RESULTS: Pattern of lung disease, ventilatory settings, blood gases, infant's vital parameters, sedation and analgesia during the periods of conventional mechanical ventilation (CMV, 6 infants), after initiation of HFOV (HFOVi, 9 infants), in the middle of its course (HFOVm), at the end (HFOVe) and after extubation (Post-Extub) were compared. All infants showed a predominant overexpanded lung pattern. Mean airway pressure was raised from a mean (SD) 12.5 (2.0) during CMV to 18.9 (2.7) cmH(2)O during HFOVi (P < 0.05), then decreased to 11.1(1.3) at HFOVe (P < 0.05). Mean FiO(2) was reduced from 0.68 (0.18) (CMV) to 0.59 (0.14) (HFOVi) then to 0.29 (0.06) (P < 0.05) at HFOVe and mean peak to peak pressure from 44.9 (12.4) cmH(2)O (HFOVi) to 21.1 (7.7) P < 0.05 (HFOVe) while mean (SD) PaCO(2) showed a trend to decrease from 72 (22) (CMV) to 47 (8) mmHg (HFVOe) and mean infants respiratory rate a trend to increase from 20 (11) (HFOVi) to 34 (14) (HFOVe) breaths/min. With usual doses of sedatives and opiates, no infant was paralysed and all were extubated to CPAP or supplemental oxygen after a mean of 120 h. CONCLUSION: RSV induced respiratory failure with hypercapnia can be managed with HFOV using high mean airway pressure and large pressure swings while preserving spontaneous breathing.     

灵芝多糖对兔失血性休克再灌注血液流变学和脂质过氧化的影响

目的:探讨灵芝多糖对家兔失血性休克再灌注损伤时血液流变学和脂质过氧化的影响及可能机制.方法:将16只家兔复制成失血性休克模型后随机分为生理盐水再灌注组和灵芝多糖再灌注组,观察休克和再灌注前后血浆脂质过氧化产物丙二醛(MDA)含量、红细胞超氧化物歧化酶(SOD)活性、全血黏度、血浆黏度和红细胞变形能力的变化,以及灵芝多糖对上述指标的影响.结果:与休克前相比,休克时血浆MDA含量、全血黏度、血浆黏度明显升高(P均<0.05),红细胞SOD活性和变形能力则明显降低(P均<0.05).生理盐水再灌注时可明显降低休克时血浆黏度(P<0.05),但对全血黏度无影响(P>0.05);而红细胞SOD活性和变形能力与休克时比较则进一步降低(P<0.05),血浆MDA含量明显升高(P<0.05).灵芝多糖再灌注时全血黏度、血浆黏度与休克时相比均降低(P均<0.05),与生理盐水组比较,红细胞SOD活性和红细胞变形能力均升高(P均<0.05),血浆MDA含量明显降低(P<0.05),全血黏度降低(P<0.05).结论:灵芝多糖可明显改善失血性休克再灌注时的血液流变学特性,改善微循环,其效果优于生理盐水;而机制可能与灵芝多糖提高红细胞SOD活性、降低血浆MDA含量、抑制血液脂质过氧化增强有关.     

Characterization of Ileal Vitamin B12 Binding Using Homogeneous Human and Hog Intrinsic Factors

Elucidation of the mechanism of intrinsic factor (IF)-mediated vitamin B(12) (B(12)) binding to ileal binding sites has been hampered by the use of crude or only partially purified preparations of IF in previous studies. We have used homogeneous human IF and hog IF isolated by affinity chromatography to study [(57)Co]B(12) binding to ileal mucosal homogenates. The following observations were made: (a) Human IF-B(12) and hog IF-B(12) were bound to human, monkey, hog, dog, rabbit, mouse, hamster, and guinea pig ileal, but not jejunal, homogenates in amounts significantly greater than free B(12) or B(12) bound to five other homogeneous B(12)-binding proteins; (b) only IF-mediated B(12) binding was localized to ileal homogenates and was inhibited by EDTA; (c) values for the association constant (K(a)) for the various ileal homogenates mentioned above and human IF-B(12) and hog IF-B(12) ranged from 0.3 x 10(9) M(-1) to 13.0 x 10(9) M(-1). Apparent differences in the K(a) for human IF-B(12) and hog IF-B(12) existed in most species; (d) the number of ileal IF-B(12) binding sites per gram (wet weight) of ileal mucosa ranged from 0.3 x 10(12) to 4.9 x 10(12). The same value was always obtained with human IF-B(12) and hog IF-B(12) for any given homogenate preparation; (c) 100-fold excesses of free B(12) or human IF and hog IF devoid of B(12) did not significantly inhibit human IF-B(12) and hog IF-B(12) binding to human and hog ileal homogenates.THESE EXPERIMENTS PERFORMED WITH HOMOGENEOUS IF INDICATE THAT: (a) gastric factors other than IF are not required for B(12) binding to ileal IF-B(12)-binding sites: (b) the mechanism of ileal IF-B(12) binding is different from that of free B(12) or of B(12) bound to non-IF-B(12)-binding proteins; (c) human IF and hog IF have different structures; (d) human IF-B(12) and hog IF-B(12) bind to the same ileal binding sites; and (c) human and hog ileal IF-B(12) binding sites bind free B(12) and human and hog IF devoid of B(12) poorly, if at all.     

Modified proteinase-activated receptor-1 and -2 derived peptides inhibit proteinase-activated receptor-2 activation by trypsin.

Trypsin activates proteinase-activated receptor-2 (PAR(2)) by a mechanism that involves the release of a tethered receptor-activating sequence. We have identified two peptides, FSLLRY-NH(2) (FSY-NH(2)) and LSIGRL-NH(2) (LS-NH(2)) that block the ability of trypsin to activate PAR(2) either in PAR(2)-expressing Kirsten virus-transformed kidney (KNRK) cell lines or in a rat aorta ring preparation. The reverse PAR(2) peptide, LRGILS-NH(2) (LRG-NH(2)) did not do so and FSY-NH(2) failed to block thrombin activation of PAR(1) in the aorta ring or in PAR(1)-expressing human embryonic kidney cells. Half-maximal inhibition (IC(50)) by FSY-NH(2) and LS-NH(2) of the activation of PAR(2) by trypsin in a PAR(2) KNRK calcium-signaling assay was observed at about 50 and 200 microM, respectively. In contrast, the activation of PAR(2) by the PAR(2)-activating peptide, SLIGRL-NH(2) (SL-NH(2)) was not inhibited by FSY-NH(2), LS-NH(2), or LRG-NH(2). In a casein proteolysis assay, neither FSY-NH(2) nor LS-NH(2) inhibited the proteolytic action of trypsin on its substrate. In addition, FSY-NH(2) and LS-NH(2) were unable to prevent trypsin from hydrolyzing a 20-amino acid peptide, GPNSKGR/SLIGRLDTPYGGC representing the trypsin cleavage/activation site of rat PAR(2). Similarly, FSY-NH(2) and LS-NH(2) failed to block the ability of trypsin to release the PAR(2) N-terminal epitope that is cleaved from the receptor upon proteolytic activation of receptor-expressing KNRK cells. We conclude that the peptides FSY-NH(2) and LS-NH(2) block the ability of trypsin to activate PAR(2) by a mechanism that does not involve a simple inhibition of trypsin proteolytic activity, but possibly by interacting with a tethered ligand receptor-docking site.     

Pharmacological profile of histaprodifens at four recombinant histamine H1 receptor species isoforms

There are differences in the pharmacological properties of phenylhistamines and histaprodifens between guinea pig histamine H(1) receptor (gpH(1)R) and human histamine H(1) receptor (hH(1)R). The aim of this study was to analyze species differences in more detail, focusing on histaprodifen derivatives and including the bovine histamine H(1) receptor (bH(1)R) and rat histamine H(1) receptor (rH(1)R). H(1)R species isoforms were coexpressed with the regulator of G protein signaling RGS4 in Sf9 insect cells. We performed [(3)H]mepyramine binding assays and steady-state GTPase assays. For a novel class of histaprodifens, the chiral histaprodifens, unique species differences between hH(1)R, bH(1)R, rH(1)R, and gpH(1)R were observed. The chiral histaprodifens 8R and 8S were both partial agonists at gpH(1)R, but only 8R was a partial agonist at the other H(1)R species isoforms. An additional phenyl group in chiral histaprodifens 10R and 10S, respectively, resulted in a switch from agonism at gpH(1)Rto antagonism at hH(1)R, bH(1)R, and rH(1)R. In general, histaprodifens showed the order of potency hH(1)R < bH(1)R < rH(1)R < gpH(1)R. An active-state model of gpH(1)R was generated with molecular dynamics simulations. Dimeric histaprodifen was docked into the binding pocket of gpH(1)R. Hydrogen bonds and electrostatic interactions were detected between dimeric histaprodifen and Asp-116, Ser-120, Lys-187, Glu-190, and Tyr-432. We conclude the following: 1) chiral histaprodifens interact differentially with H(1)R species isoforms; 2) gpH(1)R and rH(1)R, on one hand, and hH(1)R and bH(1)R, on the other hand, resemble each other structurally and pharmacologically; and 3) histaprodifens interact with H(1)R at multiple sites.     

Probing ligand-specific histamine H1- and H2-receptor conformations with NG-acylated Imidazolylpropylguanidines

Impromidine (IMP) and arpromidine (ARP)-derived guanidines are more potent and efficacious guinea pig (gp) histamine H(2)-receptor (gpH(2)R) than human (h) H(2)R agonists and histamine H(1)-receptor (H(1)R) antagonists with preference for hH(1)R relative to gpH(1)R. We examined N(G)-acylated imidazolylpropylguanidines (AIPGs), which are less basic than guanidines, at hH(2)R, gpH(2)R, rat H(2)R (rH(2)R), hH(1)R, and gpH(1)R expressed in Sf9 cells as probes for ligand-specific receptor conformations. AIPGs were similarly potent H(2)R agonists as the corresponding guanidines IMP and ARP, respectively. Exchange of pyridyl in ARP against phenyl increased AIPG potency 10-fold, yielding the most potent agonists at the hH(2)R-G(salpha) fusion protein and gpH(2)R-G(salpha) identified so far. Some AIPGs were similarly potent and efficacious at hH(2)R-G(salpha) and gpH(2)R-G(salpha). AIPGs stabilized the ternary complex in hH(2)R-G(salpha) and gpH(2)R-G(salpha) differently than the corresponding guanidines. Guanidines, AIPGs, and small H(2)R agonists exhibited distinct agonist properties at hH(2)R, gpH(2)R, and rH(2)R measuring adenylyl cyclase activity. In contrast to ARP and IMP, AIPGs were partial H(1)R agonists exhibiting higher efficacies at hH(1)R than at gpH(1)R. This is remarkable because, so far, all bulky H(1)R agonists exhibited higher efficacies at gpH(1)R than at hH(1)R. Collectively, our data suggest that AIPGs stabilize different active conformations in hH(2)R, gpH(2)R, and rH(2)R than guanidines and that, in contrast to guanidines, AIPGs are capable of stabilizing a partially active state of hH(1)R.     

CDll7在白血病细胞上的表达分析

目的 探讨细胞表面分化抗原CD117在各型白血病细胞上的表达规律及其意义。方法 采用CD45／SSC双参数散点图设门方法进行三色流式细胞术细胞表面分化抗原分析。结果急性髓系白血病(AML)患CD117表达率为68％，慢性粒细胞白血病急变期(CML-BC)患CD117表达率为80％，而在急性淋巴细胞白血病中表达率极低，仅为2％。在慢性淋巴细胞白血病、CML慢性期中阴性。在AML中CD117主要表达在M0／M1(72％)、M2(88％)、M4(50％)、M5b(75％)、M6(100％)，但在M3和M5b中表达率较低(分别为39％和29％)，在从中CD1l7的表达率高于CD54及HLA—DR。CD117与CD14在AML中的表达呈负相关。结论 CD117有助于淋巴系与髓系白血病的鉴别，并有助于白血病克隆与正常细胞的区分。     

Similar apparent constitutive activity of human histamine H(2)-receptor fused to long and short splice variants of G(salpha).

Fusion proteins allow for the analysis of receptor/G protein coupling under defined conditions. The beta(2)-adrenoceptor (beta(2)AR) fused to the long splice variant of G(salpha) (G(salphaL)) exhibits a higher apparent constitutive activity than the beta(2)-adrenoceptor fused to the short splice variant of G(salpha) (G(salphaS)). Experimentally, this results in higher efficacy and potency of partial agonists and in higher efficacy of inverse agonists at the beta(2)AR fused to G(salphaL) relative to the beta(2)AR fused to G(salphaS), indicating that the agonist-free beta(2)AR and the beta(2)AR occupied by partial agonists promote GDP dissociation from G(salphaL) more efficiently than from G(salphaS). In fact, the GDP affinity of G(salphaS) fused to the beta(2)AR is higher than the GDP affinity of G(salphaL) fused to the beta(2)AR. We asked the question whether the histamine H(2)-receptor (H(2)R) exhibits similar coupling to G(salpha) splice variants as the beta(2)AR. To address this question, we studied H(2)R-G(salpha) fusion proteins expressed in Sf9 cells. In contrast to beta(2)AR-G(salpha) fusion proteins, the potencies and efficacies of partial agonists and the efficacies of inverse agonists were similar at the H(2)R fused to G(salphaL) and G(salphaS) as assessed by guanosine-5'-O-(3-thio)triphosphate binding and/or steady-state GTPase activity. However, the time course analysis of guanosine-5'-O-(3-thio)triphosphate binding indicated that G(salphaS) fused to the H(2)R possesses a higher GDP-affinity than G(salphaL) fused to the H(2)R. Our data show that the H(2)R fused to G(salphaL) and G(salphaS) possesses similar constitutive activity and is insensitive to differences in GDP affinity of G(salpha) splice variants. Thus, GDP affinity of G proteins does not generally determine constitutive activity of receptors.     

Cofactor Role of Iodide in Peroxidase Antimicrobial Action Against Escherichia coli

The mechanism of antimicrobial activity of the peroxidase-hydrogen peroxide (H(2)O(2))-iodide (I(-)) system was investigated. Inhibition of respiration and loss of viability of Escherichia coli were used as measures of antimicrobial activity. Because the bacteria destroyed H(2)O(2), peroxidase antimicrobial action depended on the competition for H(2)O(2) between the bacteria and the peroxidase. Utilization of H(2)O(2) by the peroxidase was favored by (i) increasing either the peroxidase or the I(-) concentration, so as to increase the rate of oxidation of I(-), (ii) lowering the temperature to lower the rate of destruction of H(2)O(2) by the bacteria, and (iii) adding H(2)O(2) in small increments so as to avoid a large excess of H(2)O(2) relative to I(-). When utilization of H(2)O(2) by the peroxidase system was favored, the peroxidase system and iodine (I(2)) were equivalent. That is, antimicrobial action per mole of H(2)O(2) equaled that per mole of I(2). Also, identical antimicrobial action was obtained either by incubating the bacteria directly with the peroxidase system or by preincubating the peroxidase system so as to form I(2) and then adding the bacteria. On the other hand, peroxidase antimicrobial action could be obtained at low I(-) concentrations. These I(-) concentrations were lower than the concentration of I(2) that was required for antimicrobial action. It is proposed that peroxidase-catalyzed oxidation of I(-) yields I(2), which reacts with bacterial components to yield the oxidized components and I(-). The I(-) that is released can be reoxidized and participate again in the oxidation of bacterial components. In this way, I(-) acts as a cofactor in the peroxidase-catalyzed oxidation of bacterial components.     

Alpha(4)beta(7)/alpha(4)beta(1) dual integrin antagonists block alpha(4)beta(7)-dependent adhesion under shear flow

The alpha(4) integrin, alpha(4)beta(7), plays an important role in recruiting circulating lymphocytes to the gastrointestinal tract, where its ligand mucosal addressin cell adhesion molecule-1 (MAdCAM-1) is preferentially expressed on high endothelial venules (HEVs). Dual antagonists of alpha(4)beta(1) and alpha(4)beta(7), N-(2,6-dichlorobenzoyl)-(L)-4-(2',6'-bis-methoxyphenyl)phenylalanine (TR14035) and N-(N-[(3,5-dichlorobenzene)sulfonyl]-2-(R)-methylpropyl)-(D)-phenylalanine (compound 1), were tested for their ability to block the binding of alpha(4)beta(7)-expressing cells to soluble ligand in suspension and under in vitro and in vivo shear flow. Compound 1 and TR14035 blocked the binding of human alpha(4)beta(7) to an (125)I-MAdCAM-Ig fusion protein with IC(50) values of 2.93 and 0.75 nM, respectively. Both compounds inhibited binding of soluble ligands to alpha(4)beta(1) or alpha(4)beta(7) on cells of human or rodent origin with similar potency. Under shear flow in vitro, TR14035 and compound 1 blocked binding of human alpha(4)beta(7)-expressing RPMI-8866 cells or murine mesenteric lymph node lymphocytes to MAdCAM-Ig with IC(50) values of 0.1 and 1 microM, respectively. Intravital microscopy was used to quantitate alpha(4)-dependent adhesion of fluorescent murine lymphocytes in Peyer's patch HEVs. When cells were prestimulated with 2 mM Mn(2+) to activate alpha(4)beta(7) binding to ligand, anti-alpha(4) monoclonal antibody (mAb) [10 mg/kg (mpk) i.v.] blocked adhesion by 95%, and anti-beta(1) mAb did not block adhesion, demonstrating that this interaction was dependent on alpha(4)beta(7). TR14035 blocked adhesion to HEVs [ED(50) of 0.01-0.1 mpk i.v.], and compound 1 blocked adhesion by 47% at 10 mpk i.v. Thus, alpha(4)beta(7)/alpha(4)beta(1) antagonists blocked alpha(4)beta(7)-dependent adhesion of lymphocytes to HEVs under both in vitro and in vivo shear flow.     

Involvement of epinephrine in the presynaptic beta adrenoceptor mechanism of norepinephrine release from rat hypothalamic slices

Using high-performance liquid chromatography with electro-chemical detector, we measured field impulse (5 or 2 Hz)- and high K+ (20 mM)-evoked release of endogenous norepinephrine from rat hypothalamic slices. Release by impulses at 5 Hz was tetrodotoxin-sensitive and both types of release were Ca++-dependent. Isoproterenol (10(-10) to 10(-8) M) dose-dependently facilitated impulse-evoked release and l-propranolol (10(-8) M) shifted dose-effect curve of isoproterenol to the right. Atenolol (10(-8) to 10(-6) M) or butoxamine (10(-9) to 10(-8) M), beta-1 and beta-2-antagonist, respectively, dose-dependently antagonized the facilitatory effect of isoproterenol (10(-8) M). Tazolol (10(-8) to 10(-7) M), beta-1-agonist, and salbutamol (10(-10) to 10(-8) M), beta-2-agonist, dose-dependently increased impulse-evoked release. Epinephrine (10(-9) M) also facilitated impulse-evoked release and the action was antagonized by l-propranolol (10(-8) M). Isoproterenol (10(-8) M) also facilitated high K+-evoked release in the presence of tetrodotoxin (3 X 10(-7) M) to exclude possible involvement of axonal conduction or neuronal loops. This facilitatory effect was antagonized by l-propranolol (10(-8) M). l-Propranolol (3 X 10(-7) M) alone decreased release by impulses at 2 Hz, but the d-isomer produced no effect. When rats were pretreated with 2,3-dichloro-alpha-methylbenzylamine, an inhibitor of phenylethanolamine N-methyltransferase, the enzyme catalyzing the formation of epinephrine from norepinephrine, 80 mg/kg i.p. before decapitation, the l-propranolol-induced decrease was abolished completely.(ABSTRACT TRUNCATED AT 250 WORDS)     

In irradiation chimeras, K or D regions of the chimeric host, not of the donor lymphocytes, determine immune responsiveness of antiviral cytotoxic T cells

The H-2 haplotype of the chimeric host determines the responder phenotype of maturing T cells. Spleen cells of chimeric mice formed when (K(k) nonresponder to D(b) × K(b) responder to D(b) plus vaccinia)F(1) bone marrow cells were used to reconstitute K(b)D(b) (C57BL/6 D(b) responder) irradiated recipients generated high levels of D(b) plus vaccinia virus-specific cytotoxic T cells. The same stem cells used to reconstitute K(k)D(b) (B10.A (2R) D(b) nonresponder) irradiated recipients resulted in spleen cells that responded well to K plus vaccinia, but responsiveness to D(b) was low. A generally low response to D(k) plus vaccinia, which seems to be regulated by D(k), was confirmed in chimeras. Thus, K(d)D(d) (D(d) plus vaccinia responder) stem cells differentiating in a K(d)D(k) chimeric host failed to generate a measurable response to D(k) plus vaccinia. In contrast, stem cells from K(d)D(k) (D(k) plus vaccinia low responders) differentiating in a K(d)D(d) (K(d) and D(d) high responders to vaccinia) host do generate responsiveness to D(d) plus vaccinia. These results indicate that in chimeras, the Ir phenotype is independent of the donor T cell’s Ir genotype, and that thymic selection of a T cell’s restriction specificity for a particular H-2 allele of the chimeric host also defines that T cell’s/r phenotype.     

Radioiodination of human intrinsic factor

Human intrinsic factor (IF) saturated with (60)Co-labeled cyanocobalamin ((60)CoB(12)) was purified and then iodinated with (125)I to yield (125)I-labeled IF-(60)CoB(12) preparations of high specific activity. Sephadex G200 and DEAE-cellulose chromatography of the iodinated IF-(60)CoB(12) complex showed coincidence of the major (125)I and the (60)Co radioactivity peaks. During starch-gel electrophoresis (60)Co radioactivity from noniodinated and iodinated complexes migrated to the same extent while (125)I radioactivity from the iodinated complex migrated slightly further anodally than did the (60)Co radioactivity. After the iodinated complex was mixed with antibody to the IF-B(12) complex (antibody II) the (125)I and (60)Co radioactivity were: (a) precipitated in similar amounts by antiglobulin serum. (b) eluted coincidentally in the 19S region on Sephadex G200, and (c) excluded to the same extent from starch gel during electrophoresis. After equilibrium exchange of IF "blocking" antibody (antibody I) for (60)Co-vitamin B(12) on (125)I-labeled IF. (125)I radioactivity from the IF-antibody I complex: (a) was precipitated by antiglobulin serum, (b) was eluated in the 19S region on Sephadex G200 gel filtration, and (c) migrated slowly towards the anode on starch-gel electrophoresis. Urinary excretion of (60)Co radioactivity in pernicious anemia patients after oral administration of (60)Co-vitamin B(12) bound to freshly prepared (125)I-labeled IF was similar to that obtained with noniodinated intrinsic factor.These results show that iodination of IF-(60)CoB(12) complex does not markedly alter the chromatographic, electrophoretic, antigenic, or absorption-promoting properties of IF.     

Angiotensin II-induced relaxation of anococcygeus smooth muscle via desensitization of AT1 receptor, and activation of AT2 receptor associated with nitric-oxide synthase pathway

We evaluated the role of receptor desensitization, activation of AT(2) receptors, and enzymatic degradation of angiotensin II (Ang II) by amino/neutral endopeptidases in rat anococcygeus smooth muscle (ASM) relaxation. Ang II (0.3 nM to 10 microM) produced contractions (E(max) = 21.50 +/- 5.73%) followed by passive relaxations (E(max) reduced to 9.08 +/- 2.55%). Contractions were inhibited (E(max) = 13.67 +/- 2.03%) by losartan (0.1 microM; AT(1) antagonist) but not by PD123,319 [S-(+)-1-([4-(dimethylamino)-3-methylphenyl]methyl)-5-(diphenylacetyl)-4,5,6,7-tetrahydro-1H-imidazo(4,5-c)pyridine-6-carboxylic acid] (0.1 microM; AT(2) antagonist). Conversely, the passive relaxation was inhibited (E(max) = 18.00 +/- 3.45%) by PD123,319 but not by losartan. Ang II (0.3 microM to 100 microM) produced initial contractions (E(max) = 11.49 +/- 9.39%) followed by active relaxations [I(max) (maximum inhibition elicited by the agonist) = 47.85 +/- 4.23%] on strips precontracted by bethanechol (100 microM). A second administration of Ang II on the background of bethanechol (1 h later) resulted in stronger relaxations (I(max) = 64.03 +/- 5.47%) without the initial contractions. N(G)-Nitro-l-arginine methyl ester [nitric-oxide synthase (NOS) inhibitor], ODQ (1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one; guanylate cyclase inhibitor), PD123,319, and tetrodotoxin (neurotoxin) inhibited the relaxations. The presence of AT(1) and AT(2) receptors was confirmed by Western blot. Experiments with amastatin (1 microM) and thiorphan (1 microM), aminopeptidase, and neutral endopeptidase inhibitors, respectively, excluded the involvement of enzymatic degradation in Ang II-induced relaxation of ASM. In conclusion, the rat ASM relaxation by Ang II is the result of active and passive relaxations. The passive relaxation depends on desensitization of excitatory AT(1) receptors, and the active relaxation is mediated by stimulation of AT(2) receptors and activation of the neuronal NOS/soluble guanylate cyclase pathway.     

内源性TGF—β1、TNF—α在三氧化二砷诱导HL—60细胞凋亡中作用的研究

目的探讨内源性TGF-β     

Effects of magnesium sulphate on placental expression of endothelin 1 and its receptors in preeclampsia

OBJECTIVES: To investigate the effects of magnesium sulphate (MgSO(4)) on placental expression of endothelin 1 (ET-1) and its receptors in preeclampsia (PE). DESIGN AND METHODS: Placentas were obtained from 10 normotensive (NT group) and 18 moderate preeclamptic (PE group) women. Among the PE group, 10 patients were treated with 0.9% NaCl solution (PES) and 8 women received MgSO(4) (PEMgSO(4)). Placental mRNAs of ET-1, ET-1(A) receptor (ET-1(A)R) and ET-1(B) receptor (ET-1(B)R) were evaluated by Northern blot and quantified using densitometry. RESULTS: Placental ET-1(B)R expression was lower (P<0.05) in the PES group without significant changes in the mRNAs of ET-1 and ET-1(A)R when compared with the NT group. MgSO(4) treatment was associated with decreased ET-1 and increased ET-1(B)R (P<0.05) expression, without significant changes in ET-1(A)R. CONCLUSIONS: The results of the present study showed that moderate PE is associated with low placental expression of ET-1(B)R, and MgSO(4) treatment resulted in placental expression changes of the ET-1/receptors system.     

Pharmacologic and radioligand binding analysis of the actions of 1,4-dihydropyridine activator-antagonist pairs in smooth muscle

The actions of the enantiomers of Bay K 8644 and 202-791 were studied in rat tail artery and guinea pig ileal longitudinal smooth muscle using pharmacologic and radioligand binding assays. (-)-(S)-Bay K 8644 (below 10(-7) M in rat tail artery and 3 X 10(-7) M in guinea pig ileum) and (+)-(S)-202-791 (below 10(-6) M) induced contractions and potentiated the responses to KCl depolarization in both smooth muscle preparations. In contrast, (+)-(R)-Bay K 8644 and (-)-(R)-202-791 inhibited the responses to KCl-induced depolarization. At higher concentrations, (-)-(S)-Bay K 8644 (10(-7) to 10(-6) M) and (+)-(S)-202-791 (10(-6) to 3 X 10(-5) M) in rat tail artery, and (-)-(S)-Bay K 8644 (3 X 10(-7) to 3 X 10(-6) M) in guinea pig ileal smooth muscle relaxed the tissues contracted maximally at lower concentrations of the same drug. Cross antagonism between 1,4-dihydropyridine activators was observed when (-)-(S)-Bay K 8644 (10(-7) to 10(-6) M) relaxed the maximum contraction in response to (+)-(S)-202-791. [3H]Nitrendipine bound in a tail arterial microsomal preparation to a single class of site, with KD of 3.63 X 10(-10) M and maximum binding of 552.7 fmol mg-1 protein. In both rat tail artery and guinea pig ileal smooth muscle, (-)-(S)-Bay K 8644, (+)-(R)-Bay K 8644, (+)-(S)-202-791 and (-)-(R)-202-791 inhibited specific [3H]nitrendipine binding competitively; the Kl values correlate well to the pharmacologic EC50 (for activators) or IC50 (for antagonists, measured against 80 mM KCl depolarization) values. The biphasic response to (-)-(S)-Bay K 8644 and (+)-(S)-202-791 suggests that the properties of Ca++ channel activation and antagonism may reside within a single 1,4-dihydropyridine molecule.