尿系列微量蛋白对糖尿病肾病的诊断价值

采用双抗体夹心酶标免疫法（ＥＬＩＳＡ）及分光光度法，对７０例糖尿病（ＤＭ）患者随意新鲜１０ｍｌ尿中视黄醇结合蛋白（ＲＢＰ）、白蛋白（ＡＬＢ）、免疫球蛋白Ｇ（ＩｇＧ）、Ｎ－乙酰－β氨基葡萄糖苷酶（ＮＡＧ）的排泄率联合检测。结果表明，早期糖尿病肾病（ＤＮ）尿ＲＢＰ、ＡＬＢ、ＩｇＧ、ＮＡＧ增高，ＤＮ早期肾损害并非局限于肾小球，同时伴有肾小管病变。病程、年龄与肾损害的发生、发展及严重程度有关，提示联合检测ＤＭ患者尿系列微量蛋白有助于早期、确切判断并发肾病时病变部位及损伤程度。     

高血压患者尿NAG,β2—微球蛋白及白蛋白的变化及卡托普利对其的影响

研究高血压患者尿蛋白排泄的情况及卡托普利对其改善作用。测定４３例正常人和９１例高血压病人２４ｈ尿Ｎ－乙酰－β－Ｄ氨基葡萄糖苷酶，β２－微球蛋白，白蛋白。患者上述指标均高于正常人，且与高血压程度有关，卡托普利治疗后患者血压降至正常，尿ＮＡＧ，β２－ＭＢ，ＡＬＢ均有不同程度下降。     

NIDDM患者早期肾血流动力学及尿6－keto－PGF_（1α）、TXB_2的变化

对血压正常、多次尿蛋白定性阴性、２４小时尿微白蛋白排泄（ＵＡＥ）＜６０μｇ／ｍｉｎ、无眼底病变的２９例早期ＮＩＤＤＭ患者，测定了肾小球滤过率（ＧＦＲ）、有效肾血浆流量（ＥＲＰＦ）、肾滤过分数（ＦＦ）、尿６－ｋｅｔｏ－ＰＧＦ１α及ＴＸＢ２的变化。发现早期ＮＩＤＤＭ患者ＧＦＲ、ＦＦ增高，同时尿６－ｋｅｔｏ－ＰＧＦ１α也明显增加，而ＥＲＰＦ、尿ＴＸＢ２无明显变化，提示ＮＩＤＤＭ早期肾血流动力学变化与肾前列腺素的代谢异常有关。     

硝苯地平对高血压患者血和尿β2—微球蛋白,白蛋白,及透明质酸的影响

目的：观察硝苯地平对轻中度高血压患者血、尿微球蛋白及肾功能的影响。　方法：测定 ２０ 例正常人和 ８０ 例轻中度高血压患者用药前后血压、血和尿 β２ ┐微球蛋白（β２ ┐ Ｍ Ｇ）、透明质酸（ Ｈ Ａ）、尿白蛋白（ Ａ Ｌ Ｂ）、尿素氮（ Ｂ Ｕ Ｎ）、肌酐（ Ｃｒ）等。　结果：患者前五项指标均高于正常人。用药后血压、血和尿 β２ ┐ Ｍ Ｇ、 Ｈ Ａ、尿 Ａ Ｌ Ｂ均明显下降。　结论：硝苯地平可有效控制血压，同时降低血和尿 β２ ┐ Ｍ Ｇ、 Ｈ Ａ、尿 Ａ Ｌ Ｂ，改善肾功能。     

高血压病尿N－乙酰－β－D氨基葡萄糖苷酶活性、β_2－微球蛋白变化及其临床意义

采用放射免疫法测定了１６３例高血压病人的尿Ｎ－乙酰－β－Ｄ氨基葡萄糖苷酶（ＮＡＧ）活性和β２－微球蛋白（β２－ＭＧ）。结果表明：①高血压及老年高血压组的尿ＮＡＧ和β２－ＭＧ均高于对照组，临界高血压组与对照组比较无显著差异。②较之对照组，高血压组及老年高血压组之间的ＮＡＧ活性增高的人数比率（４４．４７％、８８．９３％）和β２－ＭＧ增高的人数比率（４６．５３％、６９．４５％）有显著差异，两组中各自的ＮＡＧ活性槽高的人数比率与尿β２－ＭＧ增高的人数比率之间的比较差异无显著意义。③经治疗血压降至正常，增高的尿ＮＡＧ活性逐渐下降，约１０周达到正常范围，但β２－ＭＧ在降压２１周后还没有显示下降趋势。以上结果提示：高血压Ⅰ期肾小管就可能受到损害；年龄增加，高血压病人的肾小管受损有增多趋势；尿ＮＡＧ活性与β２－ＭＧ在表现高血压肾小管早期损害方面有一致的临床意义，但降压后在显示肾小管的预后方面两者有着不同的意义。     

血、尿α_1－微球蛋白测定对NIDDM肾病变早期诊断的意义

对１１４例非胰岛素依赖型糖尿病（ＮＩＤＤＭ）患者血、尿α１－Ｍ、微球蛋白（α１－Ｍ）、β２－微球蛋白（β２－Ｍ）及２４小时尿微量白蛋白排泄率（ＵＡＥＲ）进行检测比较研究。结果显示：①血、尿α１－Ｍ与ＵＡＥＲ比较呈显著正相关（Ｐ＜０．０１）。②血、尿α１－Ｍ临床糖尿病肾病（ＤＮ）组、无ＤＮ组与早期ＤＮ组比较均有显著性差异（Ｐ＜０．０５～０．０１），提示可作为早期糖尿病肾病诊断的敏感指标。③血、尿β２－Ｍ对早期糖尿病肾病的诊断无价值。     

老年高血压患者血、尿β2微球蛋白、糖蛋白及尿白蛋白的测定分析

目的探讨老年高血压时肾脏受损情况。方法采用放射免疫分析法对７７例老年高血压患者进行血、尿β２微球蛋白（β２－ＭＧ）、糖蛋白（ＴＨＰ）及尿白蛋白（Ａｌｂ）的检测，并以３０例健康老人作为对照。结果患者血、尿β２－ＭＧ与尿Ａｌｂ含量均明显高于对照组（Ｐ＜０．０１）。随病程延长，β２－ＭＧ与Ａｌｂ增高愈明显。血、尿ＴＨＰ较正常组降低（Ｐ＜０．０５）。结论血、尿β２－ＭＧ、ＴＨＰ及尿Ａｌｂ的检测是用于判断肾脏功能早期病变的一项重要指标，对于判断肾小球或肾小管的损害程度、病变部位以及与高血压的关系具有重要意义     

血,尿α1—微球蛋白测定对NIDDM肾病变早期诊断的意义

对１１４例非胰岛素依赖型糖尿病（ＮＩＤＤＭ）患者血、尿α１－微球蛋白（α１－Ｍ）、β２－微球蛋白（β２－Ｍ）及２４小时尿微量白蛋白排泄率（ＵＡＥＲ）进行检测比较研究。结果显示：（１）血、尿α１－Ｍ与ＵＡＥ呈显著相前（Ｐ〈０．０１）。（２）血、尿α１－Ｍ临床糖尿病肾病（ＤＮ）组、无ＤＮＡ组与早期ＤＮ组比较均有显著性差异（Ｐ〈０．０５－０．０１），提示可作为早期糖尿病肾病诊断的敏感指标。（３）血、尿β     

早期糖尿病肾病的氨基酸治疗

早期糖尿病肾病的氨基酸治疗李蓬秋，吕月婵，陈平，林敏，张学军，陈树糖尿病肾病（ＤＮ）是糖尿病重要的慢性并发症之一，早期可表现尿微白蛋白（ＡＬＢ）、血、尿β２－微球蛋白（β２－ＭＧ）、尿免疫球蛋白（ＩｇＧ）增高，如能及时有效地治疗，可逆转肾脏损害，延缓...     

肾功能联检与高血压病早期肾损害关系的研究

采用放射免疫分析法（ＲＩＡ）对５０例轻、中重度高血压患者进行了肾功能联检〔血、尿β２－ＭＧ、尿白蛋白（ＡＬＢ）、尿球蛋白〕，并以健康人２５例作为对照组。结果表明，轻、中重度高血压及正常人三组间均存在显著性差异（Ｐ〈０．０５），高血压病程〈５年及〉５年者有显著性差异（Ｐ〈０．０５）。认为肾功能联检可早期发现高血压患者亚临床肾脏受损，并能指导治疗及判断预后。     

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.     

Hydrogen peroxide in the Burkitt's lymphoma cell line Raji provides protection against arsenic trioxide-induced apoptosis via the phosphoinositide-3 kinase signalling pathway

Many anticarcinogenic drugs kill tumour cells by inducing apoptosis. We examined the effects of hydrogen peroxide (H(2)O(2)) on arsenic trioxide (As(2)O(3))-induced cell killing. Low concentrations of H(2)O(2) (200 micromol/l) inhibited the ability of As(2)O(3) to induce apoptosis in the Burkitt's lymphoma cell line Raji. H(2)O(2) altered the form of cell death from apoptosis to pyknosis/necrosis and also lowered the degree of cell killing by As(2)O(3). H(2)O(2) was capable of preventing caspase-3 activation induced by As(2)O(3) in Raji cells. Incubation of cells with a phosphoinositide-3 kinase (PI-3K) inhibitor, wortmannin (100 nmol/l), blocked the effects of H(2)O(2) on As(2)O(3)-induced caspase-3 activation. In addition, the PI-3K inhibitor partially blocked the effects of H(2)O(2) on up-regulation of Bcl-2 and Bcl-X(L) protein expression, down-regulation of Bax protein expression, and phosphorylation of Bcl-2 and IkappaBalpha. This investigation demonstrated for the first time that low concentrations of H(2)O(2) provide protection against the in vivo of As(2)O(3)-induced apoptosis. PI-3K plays a crucial role in enhancing cell survival during H(2)O(2), inhibiting As(2)O(3)-induced apoptosis in the Burkitt's lymphoma cells. As(2)O(3)-induced cancer cell apoptosis may be enhanced by certain antioxidants in the treatment protocol.     

A multistep kinase-based sertoli cell autocrine-amplifying loop regulates prostaglandins, their receptors, and cytokines

In Sertoli epithelial cells, the IL-1beta induces prostaglandins (PG) PGE(2), PGF(2alpha) and PGI(2) (7-, 11-, and 2-fold, respectively), but not PGD(2), production. Cyclohexamide pretreatment inhibiting protein synthesis prevents IL-1beta increases in PG levels, indicating that induction requires de novo protein synthesis. IL-1beta-regulated PGE(2) and PGF(2alpha) production and cytokine expression require activation of cyclooxygenase-2 (COX-2) and c-Jun NH(2)-terminal kinase, as shown using specific enzyme inhibition. PGE(2) and PGF(2alpha) stimulate expression of IL-1alpha, -1beta, and -6, findings consistent with PG involvement in IL signaling within the seminiferous tubule. PGE(2) and PGF(2alpha) reverse COX-2-mediated inhibition of IL-1beta induction of cytokine expression and PG production. Sertoli PG receptor expression was determined; four known E-prostanoid receptor (EP) subtypes (1-4) and the F-prostanoid and prostacyclin prostanoid receptors were demonstrated using RNA and protein analyses. Pharmacological characterization of Sertoli PG receptors associated with cytokine regulation was ascertained by quantitative real-time RT-PCR analyses. IL-1beta regulates both EP(2) mRNA and protein levels, data consistent with a regulatory feedback loop. Butaprost (EP(2) agonist) and 11-deoxy PGE(1) (EP(2) and EP(4) agonist) treatments show that EP(2) receptor activation stimulates Sertoli cytokine expression. Consistent with EP(2)-cAMP signaling, protein kinase A inhibition blocks both IL-1beta- and PGE(2)-induced cytokines. Together, the data indicate an autocrine-amplifying loop involving IL-1beta-regulated Sertoli function mediated by COX-2-induced PGE(2) and PGF(2alpha) production. PGE(2) activates EP(2) and/or EP(4) receptor(s) and the protein kinase A-cAMP pathway; PGF(2alpha) activates F-prostanoid receptor-protein kinase C signaling. Further identification of the molecular mechanisms subserving these mediators may offer new insights into physiological events as well as proinflammatory-mediated pathogenesis in the testis.     

Effect of inhaled N-acetylcysteine on hydrogen peroxide exhalation in healthy subjects

N-acetylcysteine (NAC) has antioxidant properties and its oral administration decreased H(2)O(2) exhalation in patients with chronic obstructive pulmonary disease. In this study we tested whether inhaled NAC could suppress H(2)O(2) levels in exhaled breath condensate (EBC) of eight healthy subjects that have never smoked (never-smokers). Original NAC solution (ACC vial, 300 mg NAC in 3 ml solvent), NAC-placebo (vehicle), sterile 0.9% NaCl or distilled water were nebulized via the pneumatic De Vilbiss nebulizer once daily every 7 days and H(2)O(2) and thiols exhalation was measured just before, 30 min and 3 h after the end of drug administration. Additional in vitro experiments were performed to evaluate NAC stability during nebulization, reactivity with H(2)O(2) and possible H(2)O(2) generation in aqueous NAC solutions. NAC almost completely abolished H(2)O(2) exhalation 30 min after inhalation (0.02+/-0.04 vs. 0.21+/-0.09 microM, p<0.001). However, 3 h later the H(2)O(2) levels raised 1.8-fold from baseline (p<0.01). Other inhaled solutions did not affect H(2)O(2) levels. Mean thiol concentration in EBC rose (p<0.05) after treatment with NAC and reached 1.03+/-0.48 microM at 3 h. Although, 25 and 50 mM NAC completely inhibited H(2)O(2)-peroxidase-luminol-dependent chemiluminescence, detectable amounts of H(2)O(2) were generated in NAC solutions. It was accompanied by moderate loss of -SH groups. Catalase and ascorbic acid prevented H(2)O(2) formation in NAC solutions. In conclusion inhaled NAC revealed biphasic effect on H(2)O(2) exhalation in healthy subjects, which depends on direct H(2)O(2) scavenging and H(2)O(2) generation related to drug oxidation. The net result of these processes may determine anti- or pro-oxidant action of inhaled NAC.     

Evidence for P(2)-purinoceptors contribution in H(2)O(2)-induced contraction of rat aorta in the absence of endothelium

OBJECTIVE: H(2)O(2) can contract many arteries, however the underlying mechanisms are not fully understood. This study aims to test whether H(2)O(2)-induced vasoconstriction could be functionally attributed to the activation of P(2)-purinoceptors in rat aorta and to explore its possible signaling mechanisms. METHODS: Isometric tension recording of H(2)O(2) and ATP-induced contractions of rat aortic rings were compared in the absence or presence of various pharmacological tools to identify their possible common signaling pathways. RESULTS: Both H(2)O(2) and ATP induced transient phasic contractions in a concentration-dependent manner (1-1000 microM). Removal of endothelium potentiated the contractile responses to H(2)O(2) and to ATP. H(2)O(2) (30 microM)-induced phasic contraction could be abolished by catalase (800 U/ml), but not affected by SOD (150 U/ml), DMSO (5 mM) and apyrase (5 U/ml), suggesting no involvement of O(2)(-), hydroxyl free radicals and ATP release. Also, several receptor antagonists including phentolamine, atropine, methysergide and chlorpheniramine (each 3 microM) were without effect on H(2)O(2) (30 microM)-induced phasic contraction, suggesting no involvement of typical neurotransmitter release. However, both H(2)O(2) (30 microM) and ATP (1 mM)-induced phasic contractions not only presented homologous desensitization, but also showed heterogeneous desensitization. Furthermore, the phasic contractions in response to H(2)O(2) (30 microM) or ATP (100 microM) could be inhibited or abolished in a concentration dependent manner by RB-2 and suramin (10-100 microM), two widely used P(2)-purinoceptor antagonists, with only partial inhibition by Evans blue (300 microM), a moderately selective P(2x) receptor blocker, or by alpha-beta-methylene-ATP (100 microM), a selective P(2x) receptor desensitizer. On the other hand, both H(2)O(2) (30 microM) and ATP (100 microM)-induced phasic contractions were also attenuated, to different degree, by inhibitors of several enzymes including PLC, PKC, PLA(2) and cyclooxygenase. Lastly, removal of extracellular Ca(2+) or pretreatment with procaine (10 mM) and dantrolene (30 microM), two putative intracellular Ca(2+) release blockers, or with Ni(2+) (100 microM) and tetrandrine (5 microM), two Ca(2+) channel blockers, all significantly inhibited H(2)O(2) and ATP-induced contractions. However, nifedipine (1 microM), a voltage-dependent L-type Ca(2+) channel blocker, was without effect. CONCLUSIONS: Our results demonstrate that H(2)O(2)-induced phasic contraction of rat aorta involves, at least in part, the activation of P(2)-purinoceptors in the aortic smooth muscle cells     

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.     

Significance of valine/leucine247 polymorphism of beta2-glycoprotein I in antiphospholipid syndrome: increased reactivity of anti-beta2-glycoprotein I autoantibodies to the valine247 beta2-glycoprotein I variant

OBJECTIVE: To clarify the consequences of the valine/leucine polymorphism at position 247 of the beta(2)-glycoprotein I (beta(2)GPI) gene in patients with antiphospholipid syndrome (APS), by investigating the correlation between genotypes and the presence of anti-beta(2)GPI antibody. The reactivity of anti-beta(2)GPI antibodies was characterized using recombinant Val(247) and Leu(247) beta(2)GPI. METHODS: Sixty-five Japanese patients with APS and/or systemic lupus erythematosus who were positive for antiphospholipid antibodies and 61 controls were analyzed for the presence of the Val/Leu(247) polymorphism of beta(2)GPI. Polymorphism assignment was determined by polymerase chain reaction followed by restriction enzyme digestion. Recombinant Val(247) and Leu(247) beta(2)GPI were established to compare the reactivity of anti-beta(2)GPI antibodies to beta(2)GPI between these variants. The variants were prepared on polyoxygenated plates or cardiolipin-coated plates, and the reactivity of a series of anti-beta(2)GPI antibodies (immunized anti-human beta(2)GPI monoclonal antibodies [Cof-19-21] and autoimmune anti-beta(2)GPI monoclonal antibodies [EY1C8, EY2C9, and TM1G2]) and IgGs purified from patient sera was investigated. RESULTS: A positive correlation between the Val(247) allele and the presence of anti-beta(2)GPI antibodies was observed in the patient group. Human monoclonal/polyclonal anti-beta(2)GPI autoantibodies showed higher binding to recombinant Val(247) beta(2)GPI than to Leu(247) beta(2)GPI, although no difference in the reactivity of the immunized anti-beta(2)GPI between these variants was observed. Conformational optimization showed that the replacement of Leu(247) by Val(247) led to a significant alteration in the tertiary structure of domain V and/or the domain IV-V interaction. CONCLUSION: The Val(247) beta(2)GPI allele was associated with both a high frequency of anti-beta(2)GPI antibodies and stronger reactivity with anti-beta(2)GPI antibodies compared with the Leu(247) beta(2)GPI allele, suggesting that the Val(247) beta(2)GPI allele may be one of the genetic risk factors for development of APS.     

SERUM FREE 1,25-DIHYDROXYVITAMIN D AND THE FREE 1,25-DIHYDROXYVITAMIN D INDEX DURING A LONGITUDINAL STUDY OF HUMAN PREGNANCY AND LACTATION

The changes in three different indices of 1,25-dihydroxyvitamin D (1,25(OH)2D) biological activity were studied longitudinally in 35 women during late pregnancy and lactation and in 26 control women. Measurements were made of maternal serum total 1,25(OH)2D and free 1,25(OH)2D concentration (by centrifugal ultrafiltration) and the free 1,25(OH)2D index (the molar ratio of total 1,25(OH)2D and vitamin D binding protein (DBP]. During late pregnancy total 1,25(OH)2D concentrations were significantly elevated when compared to controls, as were free 1,25(OH)2D and DBP concentrations and the free 1,25(OH)2D index. Serum total 1,25(OH)2D, free 1,25(OH)2D and DBP concentrations all fell dramatically during the first 2 weeks of lactation with total 1,25(OH)2D and free 1,25(OH)2D concentrations falling to levels below those of controls. During the course of lactation both total 1,25(OH)2D and free 1,25(OH)2D levels rose significantly although they were not different from controls at 18 weeks of lactation. In contrast, the free 1,25(OH)2D index fell during the first 2 weeks of lactation, but remained at this level, significantly lower than controls. Neither urinary calcium excretion nor dietary calcium intake correlated with total or free 1,25(OH)2D, DBP, or the free 1,25(OH)2D index. The disagreement in the results of free 1,25(OH)2D concentration and free 1,25(OH)2D index demonstrates that these two approaches to measuring biologically active 1,25(OH)2D are not equivalent. In attempting to account for the increased calcium requirements of human reproduction we conclude that in pregnancy any of the 1,25(OH)2D measurements may be appropriate. In lactation, however, either 1,25(OH)2D is not a major factor or 1,25(OH)2D biological activity is inadequately represented by any of the currently available methods.     

Hydrogen peroxide differentially modulates cardiac myocyte nitric oxide synthesis

Nitric oxide (NO) and hydrogen peroxide (H(2)O(2)) are synthesized within cardiac myocytes and play key roles in modulating cardiovascular signaling. Cardiac myocytes contain both the endothelial (eNOS) and neuronal (nNOS) NO synthases, but the differential roles of these NOS isoforms and the interplay of reactive oxygen species and reactive nitrogen species in cardiac signaling pathways are poorly understood. Using a recently developed NO chemical sensor [Cu(2)(FL2E)] to study adult cardiac myocytes from wild-type, eNOS(null), and nNOS(null) mice, we discovered that physiological concentrations of H(2)O(2) activate eNOS but not nNOS. H(2)O(2)-stimulated eNOS activation depends on phosphorylation of both the AMP-activated protein kinase and kinase Akt, and leads to the robust phosphorylation of eNOS. Cardiac myocytes isolated from mice infected with lentivirus expressing the recently developed H(2)O(2) biosensor HyPer2 show marked H(2)O(2) synthesis when stimulated by angiotensin II, but not following β-adrenergic receptor activation. We discovered that the angiotensin-II-promoted increase in cardiac myocyte contractility is dependent on H(2)O(2), whereas β-adrenergic contractile responses occur independently of H(2)O(2) signaling. These studies establish differential roles for H(2)O(2) in control of cardiac contractility and receptor-dependent NOS activation in the heart, and they identify new points for modulation of NO signaling responses by oxidant stress.