Effect of Fluoride Exposure on Serum Glycoprotein Pattern and Sialic Acid Level in Rabbits

This study describes the effects of fluoride exposure on the protein profile, glycoprotein pattern, and total sialic acid concentration of serum in rabbits. For this aim; 20 healthy New Zealand rabbits were used. The rabbits were divided into two equal groups each with ten animals according to their weighing: control group and experimental group. The rabbits in control group were given drinking tap water containing 0.29 mg/l sodium fluoride and experimental group received the same tap water to which was added 40 mg/l sodium fluoride for 70 days. Blood samples were taken from each rabbit on day 70. Serum fluoride concentrations were measured by a fluoride-specific ion electrode in serum. The fluoride levels in the serum were found as 18.4 (±1.58) μg/L in control and 301.3 (±52.18) μg/L in fluoride exposed rabbits. The sialic acid levels were found as 69.2 (±0.32) mg/dL in control and 43.4 (±0.13) mg/dL in fluoride exposed group. The electrophoretic patterns of serum proteins, glycoproteins, and total sialic acid concentration were determined. Fifteen different protein fractions with molecular weights ranging from 22 to 249 kDa were displayed in the serum protein electrophoretic gel of both groups. The raw concentrations of the protein fractions decreased in fluoride exposed rabbits as compared with the control rabbits. The serum glycoprotein pattern revealed seven major protein bands from 47 to 167 kDa in experimental and control groups. The slight decrease of raw concentration of the protein bands in glycoprotein pattern of serum was observed in fluoride toxication comparing to control. The results suggest that serum TSA determination and serum protein electrophoresis can be used to evaluate prognosis of fluoride exposure as a supplementary laboratory test in combination with clinical and other laboratory findings of fluorosis.     

Coronary Collateral Circulation in Patients of Coronary Ectasia with Significant Coronary Artery Disease

Objectives

Patients with coronary ectasia (CE) usually have coexisting coronary stenosis resulting in myoischemia. Coronary collateral plays an important role in protecting myocardium from ischemia and reducing cardiovascular events. However, limited studies investigate the role of CE in coronary collaterals development.

Methods

We evaluated 1020 consecutive patients undergoing coronary angiography and 552 patients with significant coronary artery disease (SCAD), defined as diameter stenosis more than 70%, were finally analyzed. CE is defined as the ectatic diameter 1.5 times larger than adjacent reference segment. Rentrop collateral score was used to classify patients into poor (grades 0 and 1) or good (grades 2 and 3) collateral group.

Results

73 patients (13.2%) had CE lesions which were most located in the right coronary artery (53.4%). Patients with CE had a lower incidence of diabetes (43.8% vs 30.1%, p = 0.03), higher body mass index (25.4±3.5 vs 26.7±4.6, p = 0.027) and poorer coronary collateral (58.2% vs 71.2%, p = 0.040). Patients with poor collateral (n = 331) had a higher incidence of CE (15.7% vs 9.5%, p = 0.040) and fewer diseased vessels numbers (1.96±0.84 vs 2.48±0.69, p<0.001). Multivariate analysis showed diabetes (odd ratio (OR) 0.630, p = 0.026), CE (OR = 0.544, p = 0.048), and number of diseased vessels (OR = 2.488, p<0.001) were significant predictors of coronary collaterals development.

Conclusion

The presence of CE was associated with poorer coronary collateral development in patients with SCAD.     

Correlation of Chronic Renal Dysfunction and Albuminuria with Severity of Coronary Artery Lesions in Patients with Coronary Artery Disease

This study was conducted to investigate the possible correlation of chronic renal dysfunction and albuminuria with the severity of coronary artery lesions in patients with coronary artery disease (CAD). Two-hundred and ninety-nine patients who had undergone coronary angiography for suspected CAD were stratified into three groups according to the glomerular filtration rate (GFR): group I included 144 patients with normal renal function GFR >90 ml/(min × 1.73 m²), group II included 97 patients with mild renal impairment GFR 60–89 ml/(min × 1.73 m²), and group III included 58 patients with moderate renal impairment GFR <60 ml/(min × 1.73 m²). Patients were then stratified into two groups according to the albuminuria level (0; minimal, 1+, 2+, 3+): the albuminuria negative group (negative = 0) included 171 patients and the albuminuria positive group (positive = minimal, 1+, 2+, 3+) included 128 patients. Clinical features and coronary lesion characteristics were compared among these groups. Patients with more severe renal dysfunction and positive albuminuria had a higher incidence of CAD (66.7 vs. 70.1 vs. 72.4 %, p = 0.025 and 64.2 vs. 75.0 %, p = 0.032), more multi-vessel disease (31.2 vs. 41.2 vs. 53.4 %, p = 0.004 and 33.3 vs. 46.1 %, p = 0.015), more left anterior descending branch lesions (50.7 vs. 56.7 vs. 60.3 %, p = 0.012 and 49.1 vs. 61.7 %, p = 0.009), and a higher Gensini score (42.3 ± 14.7 vs. 46.1 ± 19.9 vs. 52.8 ± 21.2, p = 0.026 and 44.0 ± 16.0 vs. 50.5 ± 20.2, p = 0.017). In conclusion, chronic renal dysfunction and albuminuria may be important factors determining the occurrence and the severity of CAD. Albuminuria was an especially significant indicator at the early stage of renal dysfunction.     

血小板/淋巴细胞比值评估急性冠脉综合征冠脉病变严重程度的临床价值

目的:探讨血小板淋巴细胞比值(platelet-to-lymphocyte ratio,PLR)评估急性冠脉综合征(acute coronary syndrome,ACS)冠脉病变严重程度中的临床价值。方法:回顾性分析2015年3月至2017年3月在南京市第一医院心血管内科行冠脉造影的168例ACS患者的临床资料,其中不稳定型心绞痛(unstable angina,UA)52例,非ST段抬高型心肌梗死(non-ST-segment elevation myocardial infarction,NSTEMI)54例,ST段抬高型心肌梗死(ST-segment elevation myocardial infarction,STEMI)62例,根据冠脉造影结果进行Gensini评分,采用Spearman相关分析对PLR和Gensini评分进行相关性分析。结果:三组白细胞总数、淋巴细胞计数以及LDL比较差异均有统计学意义(P0.05),STEMI组白细胞总数、淋巴细胞计数明显高于UA组及NSTEMI组,LDL显著低于UA组及NSTEMI组,且NSTEMI组白细胞总数、淋巴细胞计数明显高于UA组,LDL显著低于UA组。此外,NSTEMI和STEMI组PLR和Gensini评分显著均高于UA组(P0.05)。Spearman相关性分析显示PLR与Gensini评分呈正相关(r=0.2205,P=0.0114)。多元逐步回归分析结果显示PLR和白细胞总数均是Gensini评分的影响因素。结论:PLR在评估ACS患者冠脉病变严重程度中具有一定的价值,其值越高,冠脉病变越重。     

Neutrophil/Lymphocyte Ratio Is Associated with Non-Calcified Plaque Burden in Patients with Coronary Artery Disease

Background

Elevations in soluble markers of inflammation and changes in leukocyte subset distribution are frequently reported in patients with coronary artery disease (CAD). Lately, the neutrophil/lymphocyte ratio has emerged as a potential marker of both CAD severity and cardiovascular prognosis.

Objectives

The aim of the study was to investigate whether neutrophil/lymphocyte ratio and other immune-inflammatory markers were related to plaque burden, as assessed by coronary computed tomography angiography (CCTA), in patients with CAD.

Methods

Twenty patients with non-ST-elevation acute coronary syndrome (NSTE-ACS) and 30 patients with stable angina (SA) underwent CCTA at two occasions, immediately prior to coronary angiography and after three months. Atherosclerotic plaques were classified as calcified, mixed and non-calcified. Blood samples were drawn at both occasions. Leukocyte subsets were analyzed by white blood cell differential counts and flow cytometry. Levels of C-reactive protein (CRP) and interleukin(IL)-6 were measured in plasma. Blood analyses were also performed in 37 healthy controls.

Results

Plaque variables did not change over 3 months, total plaque burden being similar in NSTE-ACS and SA. However, non-calcified/total plaque ratio was higher in NSTE-ACS, 0.25(0.09–0.44) vs 0.11(0.00–0.25), p<0.05. At admission, levels of monocytes, neutrophils, neutrophil/lymphocyte ratios, CD4+ T cells, CRP and IL-6 were significantly elevated, while levels of NK cells were reduced, in both patient groups as compared to controls. After 3 months, levels of monocytes, neutrophils, neutrophil/lymphocyte ratios and CD4+ T cells remained elevated in patients. Neutrophil/lymphocyte ratios and neutrophil counts correlated significantly with numbers of non-calcified plaques and also with non-calcified/total plaque ratio (r = 0.403, p = 0.010 and r = 0.382, p = 0.024, respectively), but not with total plaque burden.

Conclusions

Among immune-inflammatory markers in NSTE-ACS and SA patients, neutrophil counts and neutrophil/lymphocyte ratios were significantly correlated with non-calcified plaques. Data suggest that these easily measured biomarkers reflect the burden of vulnerable plaques in CAD.     

冠状动脉CTA联合血清HCY、Cys-C、ApoB/ApoA1比值对2型糖尿病患者合并冠状动脉病变的诊断价值

摘要 目的：探究冠状动脉CT血管造影（CTA）联合血清同型半胱氨酸（HCY）、胱抑素C（Cys-C）、载脂蛋白B/载脂蛋白A1（ApoB/ApoA1）比值对2型糖尿病（T2DM）患者合并冠状动脉病变的诊断价值。方法：回顾性选取2018年8月到2021年8月间我院收治的358例T2DM患者,均行常规生化指标、CTA检查、冠状动脉造影（CAG）检查,根据CAG检查结果为金标准将T2DM患者分为未合并冠脉病变组（190例）和合并冠脉病变组（168例）,比较两组血清HCY、Cys-C、ApoB/ApoA1比值,分析CTA与CAG诊断冠脉狭窄结果的一致性,应用受试者工作特征（ROC）曲线评估冠状动脉CTA联合血清HCY、Cys-C、ApoB/ApoA1比值对T2DM合并冠状动脉病变的诊断价值。结果：与未合并冠脉病变组比较,合并冠脉病变组血清HCY、Cys-C、ApoB、ApoB/ApoA1比值水平明显更高（P＜0.05）,ApoA1明显更低（P＜0.05）。以CAG为金标准,CTA诊断冠脉狭窄程度与CAG一致性较高（Kappa值0.748）。ROC曲线评估冠状动脉CTA诊断T2DM合并冠脉病变的AUC、灵敏度、特异度、准确度依次为0.802、74.40%、83.71%、79.11%。三项血清指标联合AUC、准确度显著优于单一指标（P＜0.05）。冠状动脉CTA联合血清HCY、Cys-C、ApoB/ApoA1比值诊断T2DM合并冠脉病变的价值显著优于各项指标单一诊断或三项血清指标联合诊断（P＜0.05）。结论：冠状动脉CTA联合血清HCY、Cys-C、ApoB/ApoA1比值诊断T2DM患者合并冠状动脉病变的价值较高,相较各项指标单一应用而言更具优势。     

Association of Serum Uric Acid and Coronary Artery Disease in Premenopausal Women

Objective

To date, no study in the published literature has investigated the role of various serum uric acid (SUA) concentrations in the development of angiographically-proven coronary artery disease (CAD) in premenopausal women. Therefore, the aim of this study was to investigate the role SUA levels may play in the prevalence, severity, and prognosis of CAD in premenopausal women.

Methods

This cross-sectional retrospective study included 607 premenopausal women who had undergone coronary angiography. The CAD diagnosis was based upon stenosis affecting ≥50% of the luminal diameter. Association of the SUA levels with CAD prevalence, severity, and clinical outcomes were assessed by statistical analysis.

Results

In total, 369 (60.8%) of the patients were diagnosed with CAD. The CAD patients had significantly higher SUA levels than those without CAD (5.3±1.9 vs. 4.8±1.7 mg/dL, P = 0.001). The SUA levels were found to be significantly associated with CAD prevalence (P = 0.013). Patients with higher levels of SUA also showed increased rates of multivessel disease and composite end-points, such as major adverse cardiac events. Furthermore, multivariate analysis identified abnormally high levels of uric acid (hyperuricemia) as an independent risk factor for CAD (OR 1.51 (1.11–2.53), P<0.05).

Conclusions

The SUA levels are significantly associated with the prevalence of CAD. The SUA levels may be a predictor for incidence of major cardiovascular events in premenopausal women.     

HDL/LDL 比值、LP（a）及s-CRP 与冠脉病变程度相关性分析

目的:研究高密度脂蛋白/低密度脂蛋白比值(HDL/LDL比值)、脂蛋白a(LP(a))及超敏C反应蛋白(s-CRP)与冠脉病变程度之间的关系。方法:对120名初发急性STEMI行急诊冠脉造影术并支架植入术患者(<12小时),并于次日晨检测空腹生化血脂分析,测得HDL/LDL比值、LP(a)及s-CRP等相关指标,冠脉造影结果根据Gensini积分系统分轻、中、重度三组,比较三组之间上述三项指标有无差异,并选取冠脉造影正常20例为对照组,比较各组间有无差异。结果:与正常组相比,心梗组HDL/LDL比值明显降低(P<0.05),各组间HDL/LDL比值亦存在差异(P<0.05),LP(a)及s-CRP在不同冠脉分级上亦存在着差异(P<0.05),以上差异均有统计学意义。结论:上述三项指标对冠脉病变严重程度有一定的预测价值。     

血清脂联素、载脂蛋白B/A1比值与颈总动脉内——中膜厚度和冠脉病变的相关性研究

目的:探讨血清脂联素、栽脂蛋白B/我脂蛋白A1比值与颈动脉内中膜厚度(IMT)的相关性,为冠心病的早期诊断提供简便、客观的指标.方法:入选经冠状动脉造影证实的冠心痛患者81例,其中单支病变组21例,多支病变组60例,另选冠状动脉造影正常者17例为对照组.采用高频超声探测双侧颈总动脉内中膜厚度(IMT),以及测定血清脂联素、载脂蛋白B/载脂蛋白A1水平,分析三者之间的相关性以及和冠心病的关系.结果:血清脂联素与颈动脉内中膜厚度呈负相关,载脂蛋白B/栽脂蛋白A1比值与颈动脉内中膜厚度呈正相关.与正常对照组相比,冠状动脉单支或多支病变组血清脂联素水平降低,而栽脂蛋白B/载脂蛋白A1比值、颈动脉内中膜厚度明显增高.结论:血清脂联素、载脂蛋白B/载脂蛋白A1比值与颈动脉内中膜厚度对于冠心痛的诊断有重要的预测价值.     

血清ApoB/ApoA1比值、TG/HDL-C比值、LDH及ALP水平与冠心病患者冠状动脉病变严重程度的关系及其预测价值分析

摘要 目的：探讨血清载脂蛋白B（ApoB）/载脂蛋白A1（ApoA1）比值、三酰甘油（TG）/高密度脂蛋白胆固醇（HDL-C）比值、乳酸脱氢酶（LDH）及碱性磷酸酶（ALP）水平与冠心病（CHD）患者冠状动脉病变严重程度的关系及其预测价值。方法：选取2019年1月-2021年12月因胸痛来我院检查并收治的185例患者,根据检查结果是否为CHD分为CHD组（120例）和对照组（65例）,根据Gensini评分将CHD组分为轻度狭窄亚组36例、中度狭窄亚组55例、重度狭窄亚组29例。入院后检测血清ApoB/ApoA1比值、TG/HDL-C比值、LDH及ALP水平。采用Spearman相关系数分析CHD患者血清ApoB/ApoA1比值、TG/HDL-C比值、LDH、ALP水平与Gensini评分的相关性,采用多因素Logistic回归分析CHD的影响因素;受试者工作特征（ROC）曲线分析血清ApoB/ApoA1比值、TG/HDL-C比值、LDH及ALP水平对CHD的预测价值。结果：与对照组比较,CHD组吸烟、饮酒、高血压、糖尿病比例和血清总胆固醇（TC）、TG、低密度脂蛋白胆固醇（LDL-C）、ApoB、ApoB/ApoA1比值、TG/HDL-C比值、LDH、ALP水平升高,HDL-C、ApoA1水平降低（P＜0.05）。轻度、中度、重度狭窄亚组血清ApoB/ApoA1比值、TG/HDL-C比值、LDH及ALP水平依次升高（P＜0.05）。CHD患者血清ApoB/ApoA1比值、TG/HDL-C比值、LDH、ALP水平与Gensini评分呈正相关（P均＜0.001）。多因素Logistic回归分析显示,高血压、血清ApoB/ApoA1比值、TG/HDL-C比值、LDH、ALP水平升高为CHD的独立危险因素（P＜0.05）。ROC曲线分析显示,血清ApoB/ApoA1比值、TG/HDL-C比值、LDH及ALP水平联合预测CHD的曲线下面积大于单独预测（P＜0.05）。结论：血清ApoB/ApoA1比值、TG/HDL-C比值、LDH、ALP水平与CHD患者冠状动脉病变严重程度有关,且联合预测CHD的价值较高。     

Sialylation and Muscle Performance: Sialic Acid Is a Marker of Muscle Ageing

Sialic acids (Sia) are widely expressed as terminal monosaccharides on eukaryotic glycoconjugates. They are involved in many cellular functions, such as cell–cell interaction and signal recognition. The key enzyme of sialic acid biosynthesis is the bifunctional UDP-N-acetylglucosamine-2-epimerase/N-acetylmannosamine kinase (GNE), which catalyses the first two steps of Sia biosynthesis in the cytosol. In this study we analysed sialylation of muscles in wild type (C57Bl/6 GNE ^+/+) and heterozygous GNE-deficient (C57Bl/6 GNE ^+/−) mice. We measured a significantly lower performance in the initial weeks of a treadmill exercise in C57Bl/6 GNE ^+/− mice compared to wild type C57Bl/6 GNE ^+/+animals. Membrane bound Sia of C57Bl/6 GNE ^+/− mice were reduced by 33–53% at week 24 and by 12–15% at week 80 in comparison to C57Bl/6 GNE ^+/+mice. Interestingly, membrane bound Sia concentration increased with age of the mice by 16–46% in C57Bl/6 GNE ^+/+, but by 87–207% in C57Bl/6 GNE ^+/−. Furthermore we could identify specific morphological changes in aged muscles. Here we propose that increased Sia concentrations in muscles are a characteristic feature of ageing and could be used as a marker for age-related changes in muscle.     

Fluoride Exposure Aggravates the Testicular Damage and Sperm Quality in Diabetic Mice: Protective Role of Ginseng and Banaba

The current study was conducted to investigate the effects of dietary zinc oxide (ZnO) on the antioxidant capacity, small intestine development, and jejunal gene expression in weaned piglets. Ninety-six 21-day-old piglets were randomly assigned to three dietary treatments. Each treatment had eight replicates with four piglets per replicate. The piglets were fed either control diet (control) or control diet supplemented with in-feed antibiotics (300 mg/kg chlortetracycline and 60 mg/kg colistin sulfate) or pharmacological doses of ZnO (3000 mg/kg). The experiment lasted 4 weeks. Blood samples were collected at days 14 and 28, while intestinal samples were harvested at day 28 of the experiment. Dietary high doses of ZnO supplementation significantly increased the body weight (BW) at day 14 and average daily gain (ADG) of days 1 to 14 in weaned piglets, when compared to control group (P < 0.05). The incidence of diarrhea of piglets fed ZnO-supplemented diets, at either days 1 to 14, days 14 to 28, or the overall experimental period, was significantly decreased in comparison with those in other groups (P < 0.05). Supplementation with ZnO increased the villus height of the duodenum and ileum in weaned piglets and decreased the crypt depth of the duodenum, when compared to the other groups (P < 0.05). Dietary ZnO supplementation decreased the malondialdehyde (MDA) concentration at either day 14 or day 28, but increased total superoxide dismutase (T-SOD) at day 14, when compared to that in the control (P < 0.05). ZnO supplementation upregulated the messenger RNA (mRNA) expression of zonula occludens-1 (ZO-1) and occludin in the jejunum mucosa of weaned piglets, compared to those in the control (P < 0.05). The pro-inflammatory cytokine interleukin-lβ (IL-1β) mRNA expression in the jejunum mucosa was downregulated in the ZnO-supplemented group, compared with the control (P < 0.05). Both in-feed antibiotics and ZnO supplementation decreased the mRNA expression of interferon-γ (IFN-γ), but increased the mRNA expression of transforming growth factor-β (TGF-β), in the jejunum mucosa of piglets, when compared to those in the control (P < 0.05). In summary, supplemental ZnO was effective on the prevention of post-weaning diarrhea (PWD) in weaned piglets and showed comparative growth-promoting effect on in-feed antibiotics, probably by the mechanism of improvement of the antioxidant capacity, restoration of intestinal barrier function and development, and modulation of immune functions.     

A Novel Red Clover Hydroxycinnamoyl Transferase Has Enzymatic Activities Consistent with a Role in Phaselic Acid Biosynthesis

Red clover (Trifolium pratense) leaves accumulate several μmol g⁻¹ fresh weight of phaselic acid [2-O-(caffeoyl)-l-malate]. Postharvest oxidation of such o-diphenols to o-quinones by endogenous polyphenol oxidases prevents breakdown of forage protein during storage. Forage crops like alfalfa (Medicago sativa) lack both polyphenol oxidase and o-diphenols, and breakdown of their protein upon harvest and storage results in economic losses and release of excess nitrogen into the environment. Understanding how red clover synthesizes o-diphenols such as phaselic acid will help in the development of forage crops utilizing this natural system of protein protection. A possible pathway for phaselic acid biosynthesis predicts a hydroxycinnamoyl transferase (HCT) capable of forming caffeoyl and/or p-coumaroyl esters with malate. Genes encoding two distinct HCTs were identified in red clover. HCT1 shares more than 75% amino acid identity with a number of well-characterized shikimate O-HCTs implicated in monolignol biosynthesis. HCT2 shares only 34% amino acid sequence identity with HCT1 and has limited sequence identity to any previously identified HCT. Expression analyses indicate that HCT1 mRNA accumulates to 4-fold higher levels in stems than in leaves, whereas HCT2 mRNA accumulates to 10-fold higher levels in leaves than in stems. Activity assays of HCT1 and HCT2 proteins expressed in Escherichia coli indicate that HCT1 transfers caffeoyl or p-coumaroyl moieties from a coenzyme A-thiolester to shikimate but not malate, whereas HCT2 transfers caffeoyl or p-coumaroyl moieties from a coenzyme A-thiolester to malate but not shikimate. Together, these results indicate that HCT1 is involved in monolignol biosynthesis and HCT2 is a novel transferase likely involved in phaselic acid biosynthesis.In contrast to many other forage legumes (e.g. alfalfa [Medicago sativa]; Jones et al., 1995), red clover (Trifolium pratense) accumulates relatively high levels of the phenylpropanoid o-diphenol phaselic acid [2-O-(caffeoyl)-l-malic acid; hereafter referred to as caffeoyl-malate or phaselic acid] in its leaves (Hatfield and Muck, 1999; Winters et al., 2008). In red clover, upon cellular disruption, phaselic acid and other o-diphenols are readily oxidized by a soluble polyphenol oxidase (PPO) to produce their corresponding o-quinones (Hatfield and Muck, 1999; Sullivan et al., 2004). The formation of such o-quinones by PPO, and the subsequent secondary reactions of these quinones, are most often associated with browning of fresh fruits and vegetables (Steffens et al., 1994), which has a negative impact on perceived quality. When preserved by ensiling, however, oxidation of o-diphenols by PPO in red clover prevents degradation of protein during storage (Sullivan et al., 2004; Sullivan and Hatfield, 2006). Although alfalfa lacks significant levels of both PPO activity and o-diphenol compounds in its leaves, red clover''s natural system of protein protection has been transferred to this forage legume by expressing a red clover PPO transgene in alfalfa and exogenously adding o-diphenol PPO substrates to the resulting tissues or tissue extracts (Sullivan et al., 2004; Sullivan and Hatfield, 2006). Because ruminant animals poorly utilize degraded protein, adaptation of the PPO system to alfalfa and other forage crops would have substantial positive economic and environmental impacts (Sullivan and Hatfield, 2006). Unfortunately, lack of system components in these forage crops, especially the o-diphenol PPO substrates, presents a challenge to practical adaptation of this natural system of protein preservation. Consequently, understanding how red clover is able to accumulate o-diphenols such as phaselic acid will be a key step to adapt the PPO/o-diphenol system to a wide range of economically important forage crops.The biosynthetic pathways whereby red clover synthesizes and accumulates phaselic acid and other o-diphenols have not been defined. However, in the Brassicaceae, hydroxycinnamoyl esters with malic acid can be made via the action of sinapoyl-Glc:malate sinapoyltransferase (SMT; EC 2.3.1), which is capable of transferring a hydroxycinnamoyl moiety from a hydroxycinnamoyl-Glc ester to a malic acid acceptor. In Arabidopsis (Arabidopsis thaliana), SNG1 (for sinapoylglucose accumulator 1), which encodes the enzyme, has been shown to be responsible for the accumulation of sinapoylmalate in seeds and leaves (Lehfeldt et al., 2000). An SMT from radish (Raphanus sativus), presumably the homolog of the Arabidopsis SNG1 gene product, has been purified to apparent homogeneity and characterized (Grawe et al., 1992). The purified enzyme is capable of utilizing sinapoyl-, feruloyl-, caffeoyl-, and to a lesser extent p-coumaroyl-Glc esters to form the corresponding malic acid esters, suggesting that it is responsible for the accumulation of these esters in vivo. In contrast, in many plants, formation of certain hydroxycinnamoyl esters is often mediated by a member of the BAHD transferase family (D''Auria, 2006) that utilize a CoA thiolester hydroxycinnamoyl donor. Some of the best characterized of these hydroxycinnamoyl transferases (HCTs) are those associated with the biosynthesis of monolignols (Hoffmann et al., 2003, 2004; Shadle et al., 2007). These are capable of transferring p-coumaroyl or caffeoyl moieties from the respective CoA thiolesters to form 5-O-esters with shikimic acid or, to a lesser extent, 3-O-esters with quinic acid. Separable enzymatic activities capable of transferring a p-coumaroyl moiety to either shikimate/quinate or to 4′-hydroxyphenyllactate in basil (Ocimum basilicum) peltate gland extracts have been identified, although genes encoding these activities have not been cloned (Gang et al., 2002). Niggeweg et al. (2004) used gene-silencing experiments to definitively demonstrate that a hydroxycinnamoyl-CoA:quinate hydroxycinnamoyl transferase (HQT) is responsible for chlorogenic acid accumulation in the Solanaceae. Although phaselic acid biosynthesis in red clover could be via a pathway utilizing SMT, lack of an apparent SNG1 homolog in a collection of red clover EST sequences derived from leaves and young plants suggests otherwise (see “Discussion”). Therefore, pathways in red clover for the biosynthesis of phaselic acid utilizing one or more BAHD family transferase (Fig. 1) should be considered. In these proposed pathways, Phe would be converted to p-coumaroyl-CoA by the sequential action of Phe ammonia lyase (PAL), cinnamate-4-hydroxylase (C4H), and 4-coumarate:CoA ligase (4CL). The action of one or more specific HCTs and one or more p-coumarate 3′-hydroxylases (C3Hs) would then result in the formation of phaselic acid.Open in a separate windowFigure 1.Possible pathways for phaselic acid biosynthesis in red clover. Proposed pathway enzymes for the production of phaselic acid include PAL, 4CL, hydroxycinnamoyl:shikimate transferase (HCT-S), hydroxycinnamoyl:malate transferase (HCT-M), and C3H. The branch point at p-coumaroyl-CoA represents two alternative pathways. For simplicity, not all reactants and products are shown.Existing literature suggests that C3H enzymes, which are cytochrome P450 enzymes (CYP98A subfamily), do not directly hydroxylate p-coumaric acid to caffeic acid but rather act on p-coumaroyl ester derivatives. For example, the enzyme from Arabidopsis hydroxylates shikimic and quinic acid esters of p-coumaric acid but only poorly or not at all p-coumaric acid or its Glc or CoA esters (Schoch et al., 2001; Franke et al., 2002). Thus, one model of phaselic acid biosynthesis is the formation of 2-O-(p-coumaroyl)-l-malic acid (hereafter referred to as p-coumaroyl-malate) by a HCT and its subsequent hydroxylation by a C3H enzyme capable of utilizing the malic acid ester as a substrate (Fig. 1, bottom, red pathway). An alternative model would require at least two HCT activities for phaselic acid biosynthesis (Fig. 1, top, blue pathway). The first activity would form a substrate suitable for hydroxylation (e.g. p-coumaroyl-shikimate, since several characterized C3H enzymes appear to favor this substrate [Schoch et al., 2001; Franke et al., 2002; Gang et al., 2002; Morant et al., 2007]). Following hydroxylation to the caffeoyl derivative by a C3H, the first HCT activity could synthesize caffeoyl-CoA via its reverse reaction (Hoffmann et al., 2003; Niggeweg et al., 2004). A second HCT activity would then transfer the caffeoyl moiety to malic acid to form phaselic acid. Both pathways predict a transferase capable of transferring a hydroxycinnamoyl moiety (either p-coumaroyl or caffeoyl) to malic acid. Also, these pathways are consistent with the observation that, at least in vitro, several characterized HCT enzymes are capable of transfer reactions utilizing either p-coumaroyl- or caffeoyl-CoA (Hoffmann et al., 2003; Niggeweg et al., 2004). The identification and characterization of two distinct HCTs from red clover, one of which has properties consistent with a role in phaselic acid biosynthesis, are reported here.     

Serum Uric Acid and Chronic Kidney Disease: The Role of Hypertension

Background

There are inconsistent findings on the role of hyperuricemia as an independent risk factor for chronic kidney disease (CKD). Hypertension has been implicated as a factor influencing the association between serum uric acid and CKD. In this population-based study we investigated the association between serum uric acid and decline in renal function and tested whether hypertension moderates this association.

Methods

We included 2601 subjects aged 55 years and over from the Rotterdam Study. Serum uric acid and estimated glomerular filtration rate (eGFR) were assessed at baseline. After average 6.5 years of follow-up, second eGFR was assessed. CKD was defined as eGFR<60 ml/min/1.73 m². All associations were corrected for socio-demographic and cardiovascular factors.

Results

Each unit (mg/dL) increase in serum uric acid was associated with 0.19 ml/min per 1.73 m² faster annual decline in eGFR. While the association between serum uric acid and incidence of CKD was not significant in our study population (Hazard Ratio: 1.12, 95% confidence interval [CI]: 0.98–1.28), incorporating our results in a meta-analysis with eleven published studies revealed a significant association (Relative Risk: 1.18, 95%CI: 1.15–1.22). In the stratified analyses, we observed that the associations of serum uric acid with eGFR decline and incident CKD were stronger in hypertensive subjects (P for interaction = 0.046 and 0.024, respectively).

Conclusions

Our findings suggest that hyperuricemia is independently associated with a decline in renal function. Stronger association in hypertensive individuals may indicate that hypertension mediates the association between serum uric acid and CKD.     

不同病因的慢性肾病患者血清氨基酸谱存在显著差异

慢性肾病(chronic kidney disease, CKD)患者血清氨基酸谱发生了显著性变化,但目前并无不同病因的CKD患者血清氨基酸谱的比较研究。本研究主要探究不同病因CKD患者血清氨基酸谱的差异,以及差异氨基酸与肾疾病发生发展的相互关系。选取79例确诊慢性肾病的成年患者,根据其病因,分糖尿病肾病组、高血压肾病组及慢性肾小球肾炎组。另选取25例性别年龄匹配的健康成年人为正常对照组。收集及处理清晨空腹血清标本,采用反相高效液相色谱法（reverse-phase high-performance liquid chromatography, RP-HPLC）测定血清中22种游离氨基酸的水平。结果显示,与正常对照组相比,3组CKD患者血清赖氨酸、丝氨酸、甘氨酸、伽马氨基丁酸(GABA)、色氨酸、亮氨酸以及酪氨酸水平均显著下降（P<0.05）,而血氨水平显著升高（P<0.05）。糖尿病肾病组患者血清苏氨酸水平明显高于其余3组（P<0.05）,而血清天冬氨酸水平显著低于其余3组（P<0.05）。慢性肾小球肾炎患者血清异亮氨酸水平显著低于糖尿病肾病及高血压肾病患者（P<0.05）。上述结果证实,慢性肾病患者血清氨基酸谱较正常对照发生显著变化,且不同病因CKD患者部分血清氨基酸水平存在显著差异。其中,色氨酸水平的差异可能是不同病因CKD患者肾功能恶化速度不一致的原因之一。     

Interferon-Gamma Increases the Ratio of Matrix Metalloproteinase-9/Tissue Inhibitor of Metalloproteinase-1 in Peripheral Monocytes from Patients with Coronary Artery Disease

Acute coronary syndromes (ACS) may be triggered by acute infections. Systemic production of interferon gamma (IFN-γ) is induced during infection and regulates the production of matrix metalloproteinases (MMPs) and their inhibitors (TIMPs), both important in plaque stability. This study evaluates the effect of IFN-γ on the MMPs/TIMP-1 ratio in cultured monocytes from 30 patients with stable coronary artery disease (CAD), 30 with unstable angina (UA) or non-ST-segment elevation myocardial infarction (NSTEMI), and 30 healthy blood donors. Supernatant concentrations of MMP-1, -2, -9, and TIMP-1 were measured by enzyme-linked immunoassays. Basal concentration of MMP-1 and TIMP-1 was similar between groups, while MMP-2 was higher in healthy individuals and MMP-9 in patients with UA/NSTEMI. Upon IFN-γ stimulation, MMP-9 secretion increased in all groups, while TIMP-1 decreased only in patients with CAD, which in turn result in a strikingly elevation in their mean MMP-9/TIMP-1 ratio. MMP-1/TIMP-1 and MMP-2/TIMP-1 ratios were <1.0 in basal conditions and after stimulation in all groups. Our results suggest that nonstimulated monocytes from patients with stable CAD show a similar behavior than those from healthy individuals. However, stimulation with IFN-γ induces an increase on the MMP-9/TIMP-1 ratio as high as that found in patients with ACS. Thus, it may bring biological plausibility to the association between acute infections and the development of ACS.     

Polynucleotide Phosphorylase Has a Role in Growth of Escherichia coli

Mutants having low levels of polynucleotide phosphorylase activity grow poorly at 45 C. All revertants isolated for their ability to grow better at that temperature also regained higher levels of polynucleotide phosphorylase and the ability to be induced for tryptophanase. Thus, a physiological role is implied for the enzyme polynculeotide phosphorylase.     

Chronic Lead Exposure Decreases the Vascular Reactivity of Rat Aortas: The Role of Hydrogen Peroxide

We investigated whether exposure to small concentrations of lead alters blood pressure and vascular reactivity. Male Wistar rats were sorted randomly into the following two groups: control (Ct) and treatment with 100 ppm of lead (Pb), which was added to drinking water, for 30 days. Systolic blood pressure (BP) was measured weekly. Following treatment, aortic ring vascular reactivity was assessed. Tissue samples were properly stored for further biochemical investigation. The lead concentration in the blood reached approximately 8 μg/dL. Treatment increased blood pressure and decreased the contractile responses of the aortic rings to phenylephrine (1 nM–100 mM). Following N-nitro-L arginine methyl ester (L-NAME) administration, contractile responses increased in both groups but did not differ significantly between them. Lead effects on R_max were decreased compared to control subjects following superoxide dismutase (SOD) administration. Catalase, diethyldithiocarbamic acid (DETCA), and apocynin increased the vasoconstrictor response induced by phenylephrine in the aortas of lead-treated rats but did not increase the vasoconstrictor response in the aortas of untreated rats. Tetraethylammonium (TEA) potentiated the vasoconstrictor response induced by phenylephrine in aortic segments in both groups, but these effects were greater in lead-treated rats. The co-incubation of TEA and catalase abolished the vasodilatory effect noted in the lead group. The present study is the first to demonstrate that blood lead concentrations well below the values established by international legislation increased blood pressure and decreased phenylephrine-induced vascular reactivity. The latter effect was associated with oxidative stress, specifically oxidative stress induced via increases in hydrogen peroxide levels and the subsequent effects of hydrogen peroxide on potassium channels.