Silicon-Carbon bond cleavage reactions of Ansa tungstenocene compounds: the [Me2Si] bridge as a site for metallocene functionalization

[Me(2)Si(Cp(Me(2)))(2)]W(H)Cl is obtained via reaction of WCl(6) with a mixture of [Me(2)Si(Cp(Me(2)))(2)]Li(2) and NaBH(4), from which the dichloride [Me(2)Si(Cp(Me(2)))(2)]WCl(2) is obtained via treatment with CHCl(3). [Me(2)Si(Cp(Me(2)))(2)]WCl(2) provides a means to access other ansa tungstenocene compounds, such as [Me(2)Si(Cp(Me(2)))(2)]WH(2), [Me(2)Si(Cp(Me(2)))(2)]WMe(2), and [Me(2)Si(Cp(Me(2)))(2)]WCO. Of most interest, the reactions of [Me(2)Si(Cp(Me(2)))(2)]W(H)Cl with organolithium reagents do not yield simple ansa tungstenocene derivatives. Specifically, the reactions of [Me(2)Si(Cp(Me(2)))(2)]W(H)Cl with MeLi, Bu(n)Li, or PhLi result in the formation of mixed-ring tungstenocene compounds resulting from C-Si cleavage and functionalization of the ansa bridge, namely (Cp(Me(2)))(eta(5),kappa(1)-C(5)H(2)Me(2)SiMe(2)CH(2))WH, (Cp(Me(2)))[eta(5),kappa(1)-C(5)H(2)Me(2)Si(Me)(Bu(n))CH(2)]WH, and (Cp(Me(2)))[eta(5),kappa(1)-C(5)H(2)Me(2)SiMe(2)(C(6)H(4))]WH, respectively. In contrast to the C-Si cleavage achieved by MeLi, Bu(n)Li, and PhLi, the ansa bridge of [Me(2)Si(Cp(Me(2)))(2)]W(H)Cl is inert to Bu(t)Li and the product obtained is the fulvene ("tuck-in") complex [Me(2)Si(Cp(Me(2)))(eta(6)-C(5)MeH(2)CH(2))]WH derived from dehydrohalogenation.     

肝炎病毒感染的肾移植受者术后并发症

目的：了解ＨＢｓＡｇ或Ａｎｔｉ－ＨＣＶ阳性对肾移植受者术后并发肝外感染、急性排异及移植肾功能不全的影响。方法：回顾分析１０１例肾移植受者的临床资料。结果：在ＨＢｓＡｇ（＋）与Ａｎｔｉ－ＨＣＶ（＋）组间上述三大并发症发生率差异不显著（Ｐ＞０．０５）；ＨＢｓＡｇ（＋）组或Ａｎｔｉ－ＨＣＶ（＋）组移植肾急性排异及肾功能不全的发生率较高，尽管较阴性组无显著差异（Ｐ＞０．０５），但肝外感染的发生率明显升高（Ｐ＜０．０５）。结论：对ＨＢｓＡｇ（＋）或Ａｎｔｉ－ＨＣＶ（＋）的肾移植受者必须密切监测肝功能，环孢素Ａ（ＣｓＡ）浓度及机体免疫状态，以选择适当的免疫抑制剂方案及剂量     

Antagonistic effects of 24R,25-dihydroxyvitamin D3 and 25-hydroxyvitamin D3 on L-type Ca2+ channels and Na+/Ca2+ exchange in enterocytes from Atlantic cod (Gadus morhua)

There is mounting evidence that vitamin D and its metabolites play important roles in regulating plasma calcium concentrations in teleost fish as in other vertebrates. The aims of the present study were to elucidate the possible cellular target mechanisms for the rapid actions of 24R,25(OH)(2)D(3), 25(OH)D(3) and 1,25(OH)(2)D(3) in Atlantic cod enterocytes at physiological doses, and to establish the concentration and thus the physiological range of circulating 24R,25(OH)(2)D(3), 25(OH)D(3) and 1,25(OH)(2)D(3) in the Atlantic cod. The plasma concentrations of 25(OH)D(3), 1,25(OH)(2)D(3) and 24R,25(OH)(2)D(3) were 15.3 +/- 2.7nM, 125.1 +/- 12.3pM and 10.1 +/- 23.5nM respectively. Exposure of enterocytes to 10mM calcium (Ca(2+)) evoked an increase in intracellular Ca(2+) concentrations ([Ca(2+)](i)). This increase was suppressed by 24R,25(OH)(2)D(3) dose-dependently, with an EC(50) of 4.9nM and a maximal inhibition of 60%. 24R,25(OH)(2)D(3) (20nM) abolished an increase in [Ca(2+)](i) (approximately 252%) in the control enterocytes exposed to 10microM S(-)-BAYK-8644, suggesting that the hormone acts by inhibiting Ca(2+) entry through L-type voltage-gated Ca(2+) channels. Administration of 20nM 24R,25(OH)(2)D(3) to enterocytes in the absence of extracellular Ca(2+) increased [Ca(2+)](i) by approximately 20%, indicating a release of Ca(2+) from intracellular stores. Administration of 25(OH)D(3) (20nM) resulted in a biphasic change in the enterocyte [Ca(2+)](i): within 1--5s, it decreased to 87 +/- 12nM below its mean basal [Ca(2+)](i) (334 +/- 13nM), followed by a rapid recovery of [Ca(2+)](i) to a new level, 10% lower than the initial [Ca(2+)](i). The rapid decrease, the recovery rate and the final [Ca(2+)](i) were all affected dose-dependently by 25(OH)D(3), with EC(50) values of 8.5, 17.0 and 18.9nM respectively. Furthermore, the effects of 25(OH)D(3) were sensitive to sodium (Na(+)), bepridil (10microM) and nifedipine (5 microM), suggesting that 25(OH)D(3) regulates the activity of both basolateral membrane-associated Na(+)/Ca(2+) exchangers and brush border membrane-associated L-type Ca(2+) channels. Administration of 25(OH)D(3) (10nM) to enterocytes in the absence of extracellular Ca(2+) increased [Ca(2+)](i) by approximately 18%, indicating a release of Ca(2+) from intracellular stores. 1,25(OH)(2)D(3) also affected enterocyte [Ca(2+)](i) in a biphasic manner: the rapid decrease, the recovery rate, and the mean final [Ca(2+)](i) were all affected dose-dependently, with EC(50) values of 8.3, 24.5 and 7.7nM respectively. The high EC(50) values for 1,25(OH)(2)D(3) compared with circulating concentrations of 1,25(OH)(2)D(3) (130pM) suggest that this effect is pharmacological, rather than of physiological relevance in enterocyte Ca(2+) homeostasis of the Atlantic cod. It is concluded that 24R,25(OH)(2)D(3) has a physiological role in decreasing intestinal Ca(2+) uptake via inactivation of L-type Ca(2+) channels, whereas the physiological role of 25(OH)D(3) is to increase enterocyte Ca(2+) transport via activation of Na(+)/Ca(2+) exchangers, concurrent with activation of L-type Ca(2+) channels.     

p53基因在亚砷酸钠致人胚胎肺成纤维细胞凋亡中的作用

目的 探讨p53、Bax、bcl-2基因在亚砷酸钠(NaAs02)致人胚胎肺成纤维细胞(HELF)凋亡中的作用.方法 分别取转染了p53质粒HELF细胞(p53组)、转染了PC质粒的HELF细胞(PC组)、常规培养的HELF细胞(正常组),在6孔板中培养48 h后,分别加入0、3、9、15 mmoL/L NaAsO2溶液,培养24 h后,用real-time PCR法检测p53、Bax、bcl-2 mRNA基因表达水平,采用免疫组织化学SABC法检测p53、Bax、bcl-2基因蛋白表达水平;用流式细胞仪检测细胞凋亡情况.结果 p53组细胞p53基因mRNA表达水平(0.51±0.29)低于PC组及正常组[(1.32±0.26),(1.00±0.20),P均<0.05],p53组p53基因蛋白表达水平[(4.10±1.20)%]低于PC组和正常组[(8.00±1.63)%、(7.90±1.79)%,P均<0.05];p53组、PC组、正常组在染砷0、3、9、15 mmol/L时,细胞凋亡率[(0.57±0.28)%、(22.91±4.86)%、(40.05±3.93)%、(44.87±3.58)%,(0.65±0.24)%、(14.09±3.49)%、(20.31±3.66)%、(32.42±3.63)%,(0.56±0.25)%、(12.14±3.70)%、(19.61±3.63)%、(30.43±2.83)%]、Bax mRNA表达水平[(12.73±3.96)、(25.12±6.42)、(104.96±26.77)、(154.04±3052),(14.63±3.57)、(36.75±3.67)、(272.26±66.11)、(846.12±243.36),(14.75±5.65)、(37.22±11.27)、(278.51±37.42)、(861.67±369.29)]、Bax蛋白表达水平[(15.07±0.83)%、(23.79±3.99)%、(3851±158)%、(53.86±124)%,(15.43±1.45)%、(36.11±1.37)%、(56.86±1.97)%、(76.09±2.01)%,(15.20±1.03)%、(35.25±1.09)%、(55.56±2.17)%、(74.48±2.85)%]均随着染毒剂量的增加而增高(P均<0.05),而bcl-2 mRNA表达水平[(443.00±244.47)、(156.79±53.18)、(62.13±13.66)、(23.10±6.44),(420.55±110.77)、(48.15±10.02)、(14.91±6.53)、(7.54±2.62),(577.75±123.22)、(49.68±10.11)、(12.41±1.28)、(7.22±1.89)]、bcl-2蛋白表达水平[(47.20±3.77)%、(41.80±2.94)%、(36.00±2.36)%、(29.00±2.91)%,(45.90±4.15)%、(35.70±2.77)%、(29.80±2.78)%、(24.80±2.66)%,(46.70±3.47)%、(36.20±2.90)%、(30.10±3.21)%、(25.10±2.28)%]均随着染毒剂量的增加而降低(P均<0.05);在染砷3、9、15 mmol/L时,p53组的细胞凋亡率、bcl-2 mRNA表达水平、bcl-2蛋白表达水平均高于同一染砷剂量的正常组和PC组(P均<0.05),而Bax mRNA表达水平、Bax基因蛋白表达水平均低于同一染砷剂量的正常组和PC组(P均<0.05).结论 p53基因减少了NaAsO2致HELF的凋亡,可能是通过改变部分凋亡途径实现.     

参麦注射液对慢性间歇性缺氧大鼠胸骨舌骨肌收缩性能的影响

目的探讨参麦注射液(SMI)对慢性间歇性缺氧大鼠胸骨舌骨肌收缩性能的影响。方法健康雄性SD大鼠30只,单纯随机抽样分为正常对照组(A组)、慢性间歇性缺氧组(B组)和参麦药物干预组(C组),对B、C组大鼠间歇缺氧(8h/d,5周)以模拟阻塞性睡眠呼吸暂停低通气综合征(OSAHS)患者慢性间歇性缺氧的特征。采用电刺激法测定等长收缩胸骨舌骨肌肌条在不同刺激频率下收缩性能的变化。结果(1)B组大鼠胸骨舌骨肌在10～100Hz的电刺激频率下的肌张力分别为(19.5±4.7)、(23.8±4.7)、(33.0±5.1)、(45.1±5.9)、(54.2±7.0)、(66.1±9.1)、(74.2±9.1)、(79.7±9.0)、(82.0±8.4)、(80.7±11.8)g/cm2,与A组比较差异均无统计学意义[A组肌张力分别为(23.2±5.6)、(26.2±5.0)、(35.1±5.4)、(46.0±8.5)、(57.0±9.9)、(69.9±9.7)、(79.2±9.5)、(85.7±7.6)、(87.9±7.9)、(86.6±12.4)g/cm2,P均>0.05];与C组比较差异均有统计学意义[(30.5±2.3)、(40.0±5.4)、(56.2±7.6)、(72.2±6.4)、(82.0±5.5)、(92.4±4.6)、(98.1±4.0)、(99.2±7.4)、(101.8±3.9)、(102.2±4.0)g/cm2,P均<0.05]。(2)在诱导疲劳试验中,B组大鼠胸骨舌骨肌1～5min张力百分比分别为(75.6±8.5)%、(41.6±7.3)%、(29.0±2.7)%、(20.4±2.9)%、(18.5±2.5)%,与A组同时间点比较差异均有统计学意义[(87.9±5.7)%、(72.1±11.5)%、(55.6±9.6)%、(39.7±10.7)%、(33.2±10.2)%,P均<0.05],与C组比较差异均有统计学意义[(87.9±4.4)%、(67.9±14.1)%、(48.4±9.9)%、(38.2±7.0)%、(33.8±9.3)%,P均<0.05]。结论慢性间歇性缺氧能够增加上气道肌的疲劳,SMI具有显著增强上气道肌收缩力和抵抗疲劳的作用。     

Inositol hexakisphosphate is a physiological signal regulating the K+-inward rectifying conductance in guard cells

(RS)-2-cis, 4-trans-abscisic acid (ABA), a naturally occurring plant stress hormone, elicited rapid agonist-specific changes in myo-inositol hexakisphosphate (InsP(6)) measured in intact guard cells of Solanum tuberosum (n = 5); these changes were not reproduced by (RS)-2-trans, 4-trans-abscisic acid, an inactive stereoisomer of ABA (n = 4). The electrophysiological effects of InsP(6) were assessed on both S. tuberosum (n = 14) and Vicia faba (n = 6) guard cell protoplasts. In both species, submicromolar concentrations of InsP(6), delivered through the patch electrode, mimicked the inhibitory effects of ABA and internal calcium (Ca(i)(2+)) on the inward rectifying K(+) current, I(K,in), in a dose-dependent manner. Steady state block of I(K,in) by InsP(6) was reached much more quickly in Vicia (3 min at approximately 1 microM) than Solanum (20-30 min). The effects of InsP(6) on I(K,in) were specific to the myo-inositol isomer and were not elicited by other conformers of InsP(6) (e.g., scyllo- or neo-). Chelation of Ca(2+) by inclusion of 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid or EGTA in the patch pipette together with InsP(6) prevented the inhibition of I(K,in), suggesting that the effect is Ca(2+) dependent. InsP(6) was approximately 100-fold more potent than Ins(1,4,5)P(3) in modulating I(K,in). Thus ABA increases InsP(6) in guard cells, and InsP(6) is a potent Ca(2+)-dependent inhibitor of I(K,in). Taken together, these results suggest that InsP(6) may play a major role in the physiological response of guard cells to ABA.     

Effects of hyperoxia on ventilatory limitation during exercise in advanced chronic obstructive pulmonary disease

We studied interrelationships between exercise endurance, ventilatory demand, operational lung volumes, and dyspnea during acute hyperoxia in ventilatory-limited patients with advanced chronic obstructive pulmonary disease (COPD). Eleven patients with COPD (FEV(1.0) = 31 +/- 3% predicted, mean +/- SEM) and chronic respiratory failure (Pa(O(2)) 52 +/- 2 mm Hg, Pa(CO(2 ))48 +/- 2 mm Hg) breathed room air (RA) or 60% O(2) during two cycle exercise tests at 50% of their maximal exercise capacity, in randomized order. Endurance time (T(lim)), dyspnea intensity (Borg Scale), ventilation (V E), breathing pattern, dynamic inspiratory capacity (IC(dyn)), and gas exchange were compared. Pa(O(2)) at end-exercise was 46 +/- 3 and 245 +/- 10 mm Hg during RA and O(2), respectively. During O(2), T(lim) increased 4.7 +/- 1.4 min (p < 0.001); slopes of Borg, V E, V CO(2), and lactate over time fell (p < 0.05); slopes of Borg-V E, V E-V CO(2), V E-lactate were unchanged. At a standardized time near end-exercise, O(2) reduced dyspnea 2.0 +/- 0.5 Borg units, V CO(2) 0.06 +/- 0.03 L/min, V E 2.8 +/- 1.0 L/min, and breathing frequency 4.4 +/- 1.1 breaths/min (p < 0.05 each). IC(dyn) and inspiratory reserve volume (IRV) increased throughout exercise with O(2) (p < 0.05). Increased IC(dyn) was explained by the combination of increased resting IRV and decreased exercise breathing frequency (r(2) = 0.83, p < 0.0005). In conclusion, improved exercise endurance during hyperoxia was explained, in part, by a combination of reduced ventilatory demand, improved operational lung volumes, and dyspnea alleviation.     

Aminoacyl-transferases and the N-end rule pathway of prokaryotic/eukaryotic specificity in a human pathogen

The N-end rule relates the in vivo half-life of a protein to the identity of its N-terminal residue. Primary destabilizing N-terminal residues (Nd(p)) are recognized directly by the targeting machinery. The recognition of secondary destabilizing N-terminal residues (Nd(s)) is preceded by conjugation of an Nd(p) residue to Nd(s) of a polypeptide substrate. In eukaryotes, ATE1-encoded arginyl-transferases (R(D,E,C*)-transferases) conjugate Arg (R), an Nd(p) residue, to Nd(s) residues Asp (D), Glu (E), or oxidized Cys residue (C*). Ubiquitin ligases recognize the N-terminal Arg of a substrate and target the (ubiquitylated) substrate to the proteasome. In prokaryotes such as Escherichia coli, Nd(p) residues Leu (L) or Phe (F) are conjugated, by the aat-encoded Leu/Phe-transferase (L/F(K,R)-transferase), to N-terminal Arg or Lys, which are Nd(s) in prokaryotes but Nd(p) in eukaryotes. In prokaryotes, substrates bearing the Nd(p) residues Leu, Phe, Trp, or Tyr are degraded by the proteasome-like ClpAP protease. Despite enzymological similarities between eukaryotic R(D,E,C*)-transferases and prokaryotic L/F(K,R)-transferases, there is no significant sequelogy (sequence similarity) between them. We identified an aminoacyl-transferase, termed Bpt, in the human pathogen Vibrio vulnificus. Although it is a sequelog of eukaryotic R(D,E,C*)-transferases, this prokaryotic transferase exhibits a "hybrid" specificity, conjugating Nd(p) Leu to Nd(s) Asp or Glu. Another aminoacyl-transferase, termed ATEL1, of the eukaryotic pathogen Plasmodium falciparum, is a sequelog of prokaryotic L/F(K,R)-transferases (Aat), but has the specificity of eukaryotic R(D,E,C*)-transferases (ATE1). Phylogenetic analysis suggests that the substrate specificity of R-transferases arose by two distinct routes during the evolution of eukaryotes.     

Effect of airway inflation pressure on forced expiratory maneuvers from raised lung volume in infants.

The raised lung volume technique is increasingly used to measure forced expiratory maneuvers in infants. However, there is no consensus regarding the optimal airway inflation pressure (P(inf)) required for such maneuvers, or the influence of small changes in P(inf) within and between infants. The aim of this study was to assess the effect of small differences (0.2-0.3 kPa) in P(inf) on forced vital capacity (FVC), forced expired volume in 0.5 sec (FEV(0.5)), and forced expired flow at 75% of vital capacity (FEF(75)), all derived from the raised volume rapid thoraco-abdominal compression (RVRTC) technique. Randomized paired forced expiratory maneuvers were obtained in 32 healthy infants ( 3.9-39.3 weeks old, 3.8-9.9 kg) with the safety pressure relief valve for P(inf) set to 2.7 kPa or 3.0 kPa (27 or 30 cm H(2)0). When mean (SD) P(inf) was increased by 8.4 (2.8)%, there was a significant (P < 0.01) increase in mean (SD) FVC, FEV(0.5), and FEF(75) by 5.8 (5.7)%, 6.1 (6)%, and 8.3 (16.2)%, respectively. In conclusion, relatively small differences in P(inf) will result in significant differences in FVC, FEV(0.5), and FEF(75) by RVRTC technique. Precision in setting and reporting the applied P(inf) is therefore essential, particularly if data are to be compared between centers.     

The nature of analogue-based free thyroxine estimates.

Clinical laboratories often use analogue-based immunoassays to estimate serum free thyroxine (FT(4)) concentrations. These assays yield FT(4) estimates that correlate closely with thyroxine (T(4)) binding protein concentrations. This correlation implies that either T(4) binding proteins or protein bound T(4) contribute to analogue-based FT(4) values. To study the contributions made by T(4) binding proteins to these FT(4) estimates further, four analogue-based FT(4) assays were applied to: (1) FT(4) solutions without T(4) binding proteins, (2) to T(4) binding protein solutions without T(4), and (3) to total T(4) solutions containing T(4) binding protein, FT(4), and protein-bound T(4). The FT(4) estimates obtained with these solutions ranged from 0.2-8.6 ng/dL, when FT(4) concentrations ranged from less than 0.2-12,000 ng/dL. In the FT(4) solutions, gravimetrically determined FT(4) concentrations were 500-12,000 ng/dL (0.5-12.0 microg/dL) without protein-bound T(4), and the FT(4) estimates obtained were 0.3-6.9 ng/dL. In the total T(4) solutions, dialyzable FT(4) concentrations were less than 0.2-59 ng/dL, retained T(4) concentrations were 499.8-11,441 ng/dL, and the analogue-based FT(4) estimates obtained were 0.2-8.6 ng/dL. Similar FT(4) estimates (0.2-8.6 ng/dL and 0.3-6.9 ng/dL) were obtained with similar concentrations of either protein-bound T(4) or FT(4). Similar test results were associated with similar total T(4) concentrations, not similar FT(4) concentrations. Protein-bound T(4) and T(4) binding protein contributed variably to test results. T(4) quantifications included large analytical losses that are unaccounted for. These assays passed tests of correlation with FT(4) concentrations, but they failed tests of specificity for FT(4) and accuracy in T(4) quantification.     

2008—2018年广州市结核病患者就诊延迟影响因素分析

目的 分析2008—2018年广州市结核病患者就诊延迟变化趋势及影响因素,为制定防治措施提供依据。 方法 通过《中国疾病预防控制信息系统》的子系统《结核病管理信息系统》,收集2008—2018年广州市登记治疗的125201例结核病患者的信息,包括户籍、性别、年龄、民族、职业、患者来源、患者分类及并发症发生情况,采用单因素和多因素logistic回归模型分析结核病患者就诊延迟的影响因素。 结果 2008—2018年广州市结核病患者从出现症状至就诊的天数中位数(四分位数)为13(2,38)d,就诊延迟率为49.25%(61656/125201)。单因素分析结果显示,女性、年龄≥65岁、少数民族、职业为儿童、患者来源为追踪、患者分类为肺外结核、存在并发症者的就诊延迟率分别为49.98%(19951/39919)、53.60%(8323/15528)、52.05%(1128/2167)、64.66%(161/249)、53.06%(5347/10078)、56.27%(3465/6158)、63.80%(1202/1884),明显高于男性(48.90%,41705/85282)、年龄<25岁(43.99%,11493/26129)、汉族(49.20%,60528/123034)、教师/医务人员/干部(46.49%,1848/3975)、患者来源为健康检查(23.94%,643/2686)、患者分类为肺结核(48.88%,58191/119043)、无并发症者(49.02%,60454/123317),差异均有统计学意义(χ²值分别为12.60、664.34、6.96、878.51、940.21、127.79、162.12,P值分别为<0.001、<0.001、0.008、<0.001、<0.001、<0.001、<0.001)。多因素logistic回归分析结果显示,以下特征的结核病患者更容易出现就诊延迟:女性[以男性为参照,OR(95%CI)=1.11(1.08~1.13)],年龄组为25~、45~、≥65岁[以<25岁年龄组为参照,OR(95%CI)值分别为1.13(1.09~1.16)、1.37(1.32~1.42)、1.40(1.33~1.47)],少数民族[以汉族为参照,OR(95%CI)=1.22(1.12~1.33)];职业为儿童、工人/民工、农民、其他[以教师/医务人员/干部为参照,OR(95%CI)值分别为2.38(1.80~3.15)、1.17(1.10~1.26)、1.38(1.28~1.48)、1.17(1.10~1.25)],患者来源为因症就诊、因症推荐、转诊、追踪[以健康检查来源为参照,OR(95%CI)值分别为3.06(2.79~3.35)、3.27(2.83~3.77)、2.78(2.54~3.05)、3.35(3.04~3.70)],肺外结核[以肺结核为参照,OR(95%CI)=1.41(1.33~1.49)],有并发症[以无并发症为参照,OR(95%CI)=1.62(1.47~1.78)]。 结论 2008—2018年广州市结核病患者就诊延迟现象较为普遍,对上述各类就诊延迟的高危因素,需要重点加强关注。     

不同胃黏膜病变的细胞增殖变化规律及其意义

目的 研究胃黏膜不同病变时细胞增殖的变化规律及其意义,寻找有效的生物学指标来预测和早期诊断胃癌。方法 采用免疫组织化学SP法检测了30例慢性浅表性胃炎(CSG)、26例慢性萎缩性胃炎(CAG)、40例肠上皮化生(IM)、22例异型增生(DYS)、22例早期胃癌(EGC)和26例进展期胃癌(AGC)的增殖细胞核抗原(PCNA)、表皮生长因子受体(EGFR)、转化生长因子β受体(TGFβR)Ⅰ和TGFβR Ⅱ的表达。所得数据采用秩和检验及Spearman等级相关分析。结果 相应于CSG、CAG、IM、DYS、EGC和AGC不同的胃黏膜病变,PCNA和EGFR的表达递增(P<0.0001),TGFβR Ⅰ(P=0.007)和TGFβR Ⅱ(P<0.0001)的表达递减。PCNA标记指数在DYS时高于CSG、CAG和IM,低于EGC和AGC,其差异有显著性(P<0.0001);EGFR在IM和DYS时比CSG和CAG明显升高,差异有显著性(P<0.0001);TGFβR Ⅰ在EGC和AGC时明显下降,与CSG相比差异有显著性(P=0.007);TGFβRⅡ在AGC时明显下降,与CSG、CAG、IM、DYS及EGC相比差异有显著性(P<0.13001)。EGFR表达与PCNA的表达呈正相关,TGFβR Ⅰ和TGFβR Ⅱ与PCNA分别呈负相关,TGFβR Ⅰ和TGFβRⅡ呈正相关。结论 不同的胃黏膜病变中,DYS是细胞增殖水平发生变化的关键环节;EGFR的升高和TGFβR的下降可能通过对细胞增生水平的调节促进胃癌的发生。     

Hypoxia and reoxygenation increase H2O2 production in rats

To test the effect of transition from sustained hypoxia to normoxia on production of reactive oxygen species (ROS) in lungs, the authors measured hydrogen peroxide (H(2)O(2)) output in the expired air of rats breathing hypoxic, normoxic, and hyperoxic gas mixtures at the end of exposure to 72 hours of hypoxia. Twenty-one male Wistar rats (200 to 280 g) were randomly assigned to 1 of 3 groups. First two groups (experimental) were kept for 3 days in normobaric hypoxic chamber (F(1)O(2) 0.1), rats of the third group (controls) breathed air. The rats were then anesthetized, intubated, placed in the plethysmograph, and their ventilation measured. Two periods of exhaled breath condensate (EBC) collection, each lasting 1 hour, were then performed to assay H(2)O(2) output. The controls breathed during both samplings air, the first experimental group breathed during first sampling period hypoxic mixture (F(1)O(2) 0.1; SH-H measurement) and then, during second period, air (SH-H-A measurement), the second experimental group breathed first air (SH-A measurement) and then hyperoxic mixture (F(1)O(2) 1.0; SH-A-O(2) measurement). Concentration of H(2)O(2) in the EBC was assayed by chemiluminescence. H(2)O(2) production in the control group was low and similar in both measurements (20+/-10 and 13+/-5 pmol/h, mean+/-SEM). Exposure to 72 hours of hypoxia increased the H(2)O(2) production to 105+/-18 pmol/h (SH-H). Transition from hypoxia to normoxia resulted in an increase in the H(2)O(2) production (SH-A 421+/-24 pmol/h, and SH-H-A 366+/-19 pmol/h). Following transition from air breathing to hyperoxia did not affect the H(2)O(2) production (SH-A-O(2) 373+/-25 pmol/h). The results showed that sustained hypoxia and transition from sustained hypoxia to normoxia increased H(2)O(2) formation in the lungs.     

Poor clinical performance of the Wessex porcine heart valve bioprosthesis at nine years' follow up.

OBJECTIVE: To assess the long term performance of the Wessex porcine bioprostheses implanted in a consecutive series of patients. DESIGN: A retrospective case series. PATIENTS: Between January 1985 and July 1991, 184 Wessex bioprostheses (78 mitral, 102 aortic, and 4 tricuspid) were implanted in 150 patients. The patients were 55% (83/150) male and 45% (67/150) female; mean age was 60 (SD 10) years. RESULTS: Hospital mortality was 9.3% (14/150). Total follow up was 696 patient-years (mean 4.7 years per patient). Linearised rates (events per 100 patient-years (SEM) for postoperative complications for patients with isolated mitral valve replacement, isolated aortic valve replacement, and multiple valve replacement were, respectively: late mortality: 4.7 (1.6), 3.3 (0.9), and 4.9 (1.9); thromboembolism: 5.8 (1.8), 3.0 (0.9), and 2.8 (1.4); valve thrombosis: 1.0 (0.7), 0.3 (0.3), and 0.7 (0.7); structural failure: 5.8 (1.7), 1.9 (0.7), and 7.1 (2.2). Actuarial freedom from complications at nine years (70% confidence interval) was: late mortality: 61 (9)%, 57 (13)%, and 59 (12)%; thromboembolism and valve thrombosis: 71 (9)%, 79 (6)%, and 81 (8)%; structural failure: 33 (14)%, 50 (16)%, and 12 (14)%; all valve related morbidity/mortality: 31 (10)%, 21 (11)%, and 7 (9)%. Stent fractures appeared in 11 of 17 explanted prostheses; actuarial freedom from stent fracture at nine years was 66 (12)%. CONCLUSIONS: The Wessex bioprosthesis is associated with high thrombogenicity, early structural dysfunction, and a high valve related morbidity/mortality which justifies very close follow up of patients fitted with them.     

Role of angiotensin II type 2 receptors and kinins in the cardioprotective effect of angiotensin II type 1 receptor antagonists in rats with heart failure

OBJECTIVES: We studied the role of angiotensin II type 2 (AT(2)) receptors and kinins in the cardioprotective effect of angiotensin II type 1 antagonists (AT(1)-ant) in rats with heart failure (HF) after myocardial infarction. BACKGROUND: The AT(1)-ant is as effective as angiotensin-converting enzyme inhibitors in treating HF, but the mechanisms whereby AT(1)-ant exert their benefits on HF in vivo are more complex than previously understood. METHODS: Brown Norway Katholiek rats (BNK), which are deficient in kinins because of a mutation in the kininogen gene, and their wild-type control (Brown Norway [BN]) underwent myocardial infarction. Two months later, they were treated for two months with: 1) vehicle; 2) AT(1)-ant (L158809, Merck, Rahway, New Jersey); 3) AT(1)-ant + AT(2)-ant (PD-123319, Parke Davis, Ann Arbor, Michigan); or 4) AT(1)-ant + kinin B(2) receptor antagonist (B(2)-ant) (icatibant) (only BN). We measured left ventricular weight (LVW) gravimetrically, myocyte cross-sectional area (MCSA) and interstitial collagen fraction (ICF) histologically, and ejection fraction by ventriculography. RESULTS: Development of HF was comparable in BN and BNK rats. The AT(1)-ant reduced LVW and MCSA and the AT(2)-ant blocked these effects in BN rats, but the B(2)-ant did not. The AT(1)-ant reduced LVW and MCSA in BNK rats, and this effect was reversed by the AT(2)-ant. In BN rats, ICF was reduced and LVEF increased by AT(1)-ant, and both AT(2)-ant and B(2)-ant reversed these effects. In BNK rats, the AT(1)-ant failed to reduce ICF, and its therapeutic effect on LVEF was significantly blunted. CONCLUSIONS: In HF, the AT(2) receptor plays an important role in the therapeutic effects of AT(1)-ant, and this effect may be mediated partly through kinins; however, kinins appear to play a lesser role in the antihypertrophic effect of AT(1)-ant.     

Relaxation of vascular smooth muscle by cicletanine in aged wistar aorta under stress conditions: importance of nitric oxide

The vascular mechanism of action of cicletanine, an antihypertensive agent, was studied on isolated Wistar rat aortas (24-months-old) in presence and in absence of endothelium in two different stress conditions, normoxic and hypoxic, in presence of norepinephrine (NE). Under normoxic conditions, in presence of endothelium, cicletanine (10(-9)-10(-5)M) induced a concentration-dependent relaxation, whereas in absence of endothelium, cicletanine (10(-9)-10(-5)M) was ineffective although it relaxed the smooth muscle at higher concentrations (10(-4)M). At pharmacologic concentrations (below or equal 10(-5)M), relaxation induced by cicletanine, in presence of endothelium, was prevented by N(omega)-nitro-L-arginine (L-NNA) (P <.005) and relaxation induced by the highest concentration (10(-4)M) was reversed by BaCl2 (P <.005). Under hypoxic conditions, in presence of NE and endothelium, the aorta displayed an increased developed tension that was significantly (P <.05) attenuated by cicletanine (10(-5)M) and insensitive to indomethacine (10(-7)M). When the two compounds were added together, the relaxation induced by cicletanine was significantly improved (P <.005). These results indicated that cicletanine, under stress conditions, relaxes vascular smooth muscle through an endothelium-dependent action mediated by the nitric oxide (NO) synthase pathway. We proposed that the observed vascular effects could be associated with the counter-regulation mechanisms linked to the antihypertensive action of cicletanine.     

Configurationally homogeneous diastereomers of a linear hexa(tertiary phosphine): enantioselective self-assembly of a double-stranded parallel helicate of the type (P)-[Cu(3)(hexaphos)(2)](PF(6))(3)

Three configurationally homogeneous diastereomers of the linear hexa(tertiary phosphine) Ph(2)PCH(2)CH(2)P(Ph)CH(2)CH(2)P(Ph)CH(2)CH(2)P(Ph)CH(2)CH(2)P(Ph)CH(2)CH(2)PPh(2) (hexaphos) have been isolated in enantiomerically pure form, namely (R,S,S,R)-, (R,S,S,S)-, and (S,S,S,S)-hexaphos. The strongly helicating (R,S,S,R)-(-) form of the ligand combines with copper(I) ions to generate by stereoselective self-assembly the P enantiomer of a parallel helicate of the type [Cu(3)(hexaphos)(2)](PF(6))(3), which has been characterized by x-ray crystallography. Theoretical modeling of the cation indicates that it is the relationship between the helicities of the two 10-membered rings containing the three copper ions, each of which has the twist-boat-chair-boat conformation, and the configurations of the three chiral, tetrahedral copper stereocenters of P configuration that determines the stereochemistry of the parallel and double alpha-helix conformers of the double-stranded trinuclear metal helicate.     

Estradiol supplementation modulates growth hormone (GH) secretory-burst waveform and recombinant human insulin-like growth factor-I-enforced suppression of endogenously driven GH release in postmenopausal women

The present study tests the mechanistic postulate that estrogen confers resistance to negative feedback by systemic IGF-I. To this end, eight postmenopausal women received a constant iv infusion of recombinant human (rh)IGF-I (10 micro g/kg.h x 6 h) and saline in randomized order on the 10th day of supplementation with oral estradiol (E(2)) and placebo (Pl). GH secretion was quantitated by 10-min blood sampling, immunochemiluminometry assay, and deconvolution analysis. Administration of E(2) compared with Pl followed by saline infusion: 1) stimulated pulsatile GH secretion ( micro g/liter.6 h), viz., 12 +/- 3.3 (Pl) and 18 +/- 4.6 (E(2)) (mean +/- SEM, paired comparison, P < 0.05); 2) halved the time latency (min) to achieve peak GH secretion after GHRH injection, 24 +/- 2.2 (Pl) and 12 +/- 2.1 (E(2)) (P < 0.01); and 3) did not alter the mass of GH secreted ( micro g/liter) in response to a maximally effective dose of GHRH, 30 +/- 7.2 (Pl) and 37 +/- 11 (E(2)). Exposure to E(2) compared with Pl followed by rhIGF-I infusion: 1) accelerated the rate of decline of GH concentrations by 3.3-fold, viz., absolute slope ( micro g/liter.1000 min), 3.8 (range, 2.5-5.0) (Pl) and 12 (range, 10-14) (E(2)) (P < 0.001); 2) augmented the algebraic decrement in GH concentrations ( micro g/liter) enforced by rhIGF-I infusion, 0.73 +/- 0.21 (Pl) and 1.6 +/- 0.25 (E(2)) (P < 0.01); 3) halved the time delay (min) to peak GHRH-induced GH secretion, 20 +/- 1.2 (Pl) vs. 10 +/- 1.3 (E(2)) min (P < 0.01). In contradistinction, E(2) did not alter: 1) the capability of rhIGF-I to suppress GHRH-stimulated GH secretory burst mass significantly, viz., by 50 +/- 8% (Pl) and 52 +/- 14% (E(2)) (P < 0.05 each vs. saline); 2) the hourly rate of rise of infused (total) IGF-I concentrations; and 3) total and ultrafiltratably free IGF-I concentrations ( micro g/liter) attained at the end of the two rhIGF-I infusions. In summary, compared with Pl, E(2) supplementation in postmenopausal women: 1) amplifies endogenously driven GH secretory-burst mass; 2) initiates rapid onset of GHRH-stimulated GH release; and 3) potentiates IGF-I-dependent suppression of unstimulated GH concentrations. Based upon companion modeling data, we postulate that E(2) facilitates the upstroke and IGF-I enforces the downstroke of high-amplitude GH secretory bursts in estrogen-replete individuals.     

The heart in dermatomyositis and polymyositis

We studied eleven consecutive patients: eight with Dermatomyositis (DM) and three with Polymyositis (PM) from the cardiological point of view through non invasive methods. Nine patients (82%) had some kind of cardiopulmonary complications as shown by any of the used methods. Symptoms: eight (73%) referred some kind of cardiopulmonary symptoms, mainly dyspnea; Physical examination; in seven (64%) was abnormal, detecting increased second pulmonary sound in four (36%), findings of mitral valve prolapse (MVP) in two (18%) and in two (18%) S3 gallop; Electrocardiogram: in seven (64%) was abnormal; six (55%) had some kind of heart enlargement corresponding four (36%) to right atrial or ventricular hypertrophy (RAH & RVH) and two (18%) to left ventricular hypertrophy (LVH), three (27%) had incomplete or complete right bundle branch block, one (9%) had bifascicular block and one (9%) left anterior hemiblock. Two (18%) had sinus tachycardia and two (18%) atrial premature contractions; d) chest ray: six (55%) were abnormal, among them, three (27%) had pulmonary fibrosis, three (27%) had RAH and/or RVH, two (18%) had LVH and one (9%) pericardial effusion; e) Echocardiogram: was abnormal in eight (73%), corresponding three (27%) to RVH, three to MVP which has been considered rare, in two (18%) congestive cardiomyopathy, in two (18%) pericardial effusion and in one (9%) type "A" paradoxical septal movement.     

Three distinct types of Ca(2+) waves in Langendorff-perfused rat heart revealed by real-time confocal microscopy

Although Ca(2+) waves in cardiac myocytes are regarded as arrhythmogenic substrates, their properties in the heart in situ are poorly understood. On the hypothesis that Ca(2+) waves in the heart behave diversely and some of them influence the cardiac function, we analyzed their incidence, propagation velocity, and intercellular propagation at the subepicardial myocardium of fluo 3-loaded rat whole hearts using real-time laser scanning confocal microscopy. We classified Ca(2+) waves into 3 types. In intact regions showing homogeneous Ca(2+) transients under sinus rhythm (2 mmol/L [Ca(2+)](o)), Ca(2+) waves did not occur. Under quiescence, the waves occurred sporadically (3.8 waves. min(-1) x cell(-1)), with a velocity of 84 microm/s, a decline half-time (t(1/2)) of 0.16 seconds, and rare intercellular propagation (propagation ratio <0.06) (sporadic wave). In contrast, in presumably Ca(2+)-overloaded regions showing higher fluorescent intensity (113% versus the intact regions), Ca(2+) waves occurred at 28 waves x min(-1) x cell(-1) under quiescence with a higher velocity (116 microm/s), longer decline time (t(1/2) = 0.41 second), and occasional intercellular propagation (propagation ratio = 0.23) (Ca(2+)-overloaded wave). In regions with much higher fluorescent intensity (124% versus the intact region), Ca(2+) waves occurred with a high incidence (133 waves x min(-1) x cell(-1)) and little intercellular propagation (agonal wave). We conclude that the spatiotemporal properties of Ca(2+) waves in the heart are diverse and modulated by the Ca(2+)-loading state. The sporadic waves would not affect cardiac function, but prevalent Ca(2+)-overloaded and agonal waves may induce contractile failure and arrhythmias.