Molecular cloning of the zeta chain of the T cell antigen receptor

The T cell antigen receptor is a multi-subunit receptor complex present on the surface of all mature and many developing T cells. It consists of clonotypic heterodimers noncovalently linked to five invariant chains that are encoded by four genes and referred to as the CD3 complex. The CD3 gamma, delta, and epsilon chains have been molecularly characterized. In this report the molecular cloning of a complementary DNA encoding the zeta chain of the murine T cell antigen receptor is described. The predicted protein sequence of the zeta chain suggests a structure distinct from those of any of the previously described receptor subunits.

Activation-induced ubiquitination of the T cell antigen receptor

The zeta subunit of the T cell antigen receptor (TCR) exists primarily as a disulfide-linked homodimer. This receptor subunit is important in TCR-mediated signal transduction and is a substrate for a TCR-activated protein tyrosine kinase. The zeta chain was found to undergo ubiquitination in response to receptor engagement. This posttranslational modification occurred in normal T cells and tumor lines. Both nonphosphorylated and phosphorylated zeta molecules were modified, and at least one other TCR subunit, CD3 delta, was also ubiquitinated after activation of the receptor. These findings suggest an expanded role for ubiquitination in transmembrane receptor function.

Apoptosis caused by oxidized LDL is manganese superoxide dismutase and p53 dependent

Oxidized low density lipoprotein (oxLDL) induces apoptosis in human macrophages (Mphi), a significant feature in atherogenesis. We found that induction of apoptosis in Mphi by oxLDL, C2-ceramide, tumor necrosis factor alpha (TNF-alpha), and hydrogen peroxide (H2O2) was associated with enhanced expression of manganese superoxide dismutase (MnSOD) and p53. Treatment of cells with p53 or MnSOD antisense oligonucleotides prior to stimulation with oxLDL, C2-ceramide, TNF-alpha, or H2O2 caused an inhibition of the expression of the respective protein together with a marked reduction of apoptosis. Exposure to N-acetylcysteine before treatment with oxLDL, C2-ceramide, TNF-alpha, or H2O2 reversed a decrease in cellular glutathione concentrations as well as the enhanced production of p53 and MnSOD mRNA and protein. In apoptotic macrophages of human atherosclerotic plaques, colocalization of MnSOD and p53 immunoreactivity was found. These results indicate that in oxLDL-induced apoptosis, a concomitant induction of p53 and MnSOD is critical, and suggest that it is at least in part due to an enhancement of the sphingomyelin/ceramide pathway.

Synaptic development is controlled in the periactive zones of Drosophila synapses

A cell-adhesion molecule fasciclin 2 (FAS2), which is required for synaptic growth and still life (SIF), an activator of RAC, were found to localize in the surrounding region of the active zone, defining the periactive zone in Drosophila neuromuscular synapses. BetaPS integrin and discs large (DLG), both involved in synaptic development, also decorated the zone. However, shibire (SHI), the Drosophila dynamin that regulates endocytosis, was found in the distinct region. Mutant analyses showed that sif genetically interacted with Fas2 in synaptic growth and that the proper localization of SIF required FAS2, suggesting that they are components in related signaling pathways that locally function in the periactive zones. We propose that neurotransmission and synaptic growth are primarily regulated in segregated subcellular spaces, active zones and periactive zones, respectively.

Induction of mitochondrial manganese superoxide dismutase in macrophages by oxidized LDL: its relevance in atherosclerosis of humans and heritable hyperlipidemic rabbits

The objective of the study was to analyze the intracellular antioxidative response of macrophages (Mphi) exposed to increased levels of low density lipoprotein (LDL). We studied manganese superoxide dismutase (MnSOD) and, in part, GSH in cultured human and rabbit Mphi, and in atheromatous arterial tissue of humans and heritable hyperlipidemic (HHL) rabbits. Incubation of human Mphi with oxidized-LDL (ox-LDL) resulted in an induction of MnSOD mRNA production as shown by RT-PCR. MnSOD immunoreactivity (IR) was found to be located in the mitochondria of Mphi. In HHL rabbits, MnSOD activity and GSH concentration were significantly increased in atherosclerotic intima compared to the media of the aorta, but significantly decreased (P<0.01) in larger plaques compared with smaller ones, resulting in a significant inverse correlation of MnSOD activity (r=-0.67, P<0.001) and GSH concentration (r=-0.57, P<0.01) with plaque size. Immunohistology of the atherosclerotic intima revealed MnSOD-IR in Mac-1 (CD 11b/CD 18)-immunoreactive (ir) Mphi of human arteries and, similarly, in RAM-11-ir Mphi of rabbit ones. The relation of MnSOD-ir Mphi decreased with plaque advancement, which is consistent with biochemical findings. Most MnSOD-ir Mphi in atherosclerotic plaques revealed TUNEL-positive nuclei, indicating DNA strand breaks, and p53-IR. We conclude that mitochondrial antioxidants such as MnSOD are induced in Mphi in vitro and in atherosclerotic arteries as a reply to increased mitochondrial oxidation. As normal consequences of an increased oxidative stress due to the exposure to ox-LDL nuclear DNA strand breaks occur, which are suggested to be a signal to increase p53 protein levels. Reactive oxygen species-mediated mitochondrial-dependent pathways are suggested as major contributing pathomechanisms to nuclear damage, which eventually may result in apoptosis. A common response to increased oxidative stress due to modified LDL is presumed in rabbit and human atherosclerotic plaques.

Synthesis and receptor affinities of some conformationally restricted analogues of the dopamine D1 selective ligand (5R)-8-chloro-2,3,4,5-tetrahydro-3-methyl-5-phenyl- 1H-3-benzazepin-7-ol

The synthesis of a structurally novel series of 6,6a,7,8,9,13b-hexahydro-5H-benzo[d]naphtho[2,1-b]azepines (2), conformationally restricted analogues of the dopamine D1 antagonist (5R)-8-chloro-2,3,4,5-tetrahydro-3-methyl-5-phenyl-1H-3-benzazepin -7-ol (SCH 23390, 1c), is described. Affinity for D1 receptors was determined by competition for rat striatal binding sites labeled by [3H]SCH 23390; affinity for D2 receptors was similarly determined by competition experiments using [3H]spiperone. Compounds in this series having the B/C-trans ring junction (2b and related analogues), where the D ring is unequivocally fixed in an equatorial orientation, possess considerably more D1 receptor affinity and selectivity vs the D2 receptor than the conformationally mobile cis stereoisomers (2a), thus leading to the conclusion that axial substituents at the 4- or 5-positions of the benzazepine nucleus are detrimental to D1 receptor affinity. Resolution and X-ray analysis demonstrated that D1 receptor affinity was preferentially associated with the (-)-6aS,13bR enantiomer of 2b.

Vaginal birth after cesarean section in twin gestation

OBJECTIVE

We report a 10-year experience with vaginal birth after cesarean section in women with twins.

STUDY DESIGN

Data were gathered from labor and delivery records and maternal and neonatal hospital charts. Women with a vertical uterine scar, a previous uterine rupture, an unrepaired dehiscence, or obstetric contraindications to labor were excluded from a trial of labor. Full-thickness uterine defects requiring intervention were classified as ruptures; all others were classified as dehiscences.

RESULTS

Between Jan. 1, 1985, and Dec. 31, 1994, at Los Angeles County/University of Southern California Women's Hospital, 210 women with previous cesarean births were delivered of twins. One hundred eighteen (56%) underwent repeat cesarean delivery without a trial of labor. Ninety-two (44%) undertook a trial of labor with no uterine ruptures and no increase in maternal or perinatal morbidity or mortality.

CONCLUSIONS

In women with twins a trial of labor after a previous cesarean section is a safe and effective alternative to routine repeat cesarean delivery.

Comparative analysis of the bacterial community compositions of the shrimp intestine, surrounding water and sediment

AIMS

To reveal the relationship of the bacterial communities in shrimp intestine and surrounding environments.

METHODS AND RESULTS

We examined bacterial communities in the intestine of pacific white shrimp, Litopenaeus vannamei, the surrounding water and sediment by high-throughput sequencing analysis. Sequences were clustered into operational taxonomic units (OTUs) at 97% similarity levels, which ranged from 4956 to 5976 in each sample. All OTUs were affiliated with at least 64 phyla. The 10 most abundant phyla were Proteobacteria, Cyanobacteria, Bacteroidetes, Chloroflexi, Firmicutes, Acidobacteria, Actinobacteria, Planctomycetes, Gemmatimonadetes and Verrucomicrobia. The relationship of bacterial communities in the intestine and the surroundings was also investigated. A total of 1395 OTUs shared in the three habitats, accounting for 80, 65 and 77% in the intestine, the surrounding water and sediment respectively. There were 352, 891, 833 unique OTUs in intestine, surrounding water and sediment. Welch's t-test analysis showed that the abundances of some taxa were significantly different between the shrimp intestine and surroundings. Unweighted pair-group method with arithmetic mean analysis revealed that there was a generally similar bacterial community composition in three environments.

CONCLUSIONS

These results showed that the bacterial compositions are mostly the same in shrimp intestine, water and sediment, but with different relative abundances of the bacterial communities.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study provided valuable findings on the relationship of the bacterial communities in shrimp intestine, the surrounding water and sediment, which can expand our knowledge of the broad trend on bacterial community in shrimp cultural ecosystems.

Longitudinal spin Seebeck effect free from the proximity Nernst effect

This Letter provides evidence for intrinsic longitudinal spin Seebeck effects (LSSEs) that are free from the anomalous Nernst effect (ANE) caused by an extrinsic proximity effect. We report the observation of LSSEs in Au/Y(3)Fe(5)O(12) (YIG) and Pt/Cu/YIG systems, showing that the LSSE appears even when the mechanism of the proximity ANE is clearly removed. In the conventional Pt/YIG structure, furthermore, we separate the LSSE from the ANE by comparing the voltages in different magnetization and temperature-gradient configurations; the ANE contamination was found to be negligibly small even in the Pt/YIG structure.

Cardiac function and cytotoxic aldehyde production in a murine model of chronic iron-overload

OBJECTIVES

To determine the relationship between the total chronic dose of iron administered, ex-vivo cardiac function and the concentrations of cytotoxic aldehydes in heart tissue of a murine model.

METHODS

In the first experiment, 34 male B6D2F1 mice were randomized to receive intraperitoneal injections of 5, 10 or 20 mg of iron dextran for three weeks, or a placebo control. The mice were subsequently randomized to undergo ex-vivo assessment of cardiac function. In the second experiment, free radical generation, quantified by the presence of 20 separate cytotoxic aldehydes, was assessed in heart tissue of 40 mice that were randomized to receive chronic treatment with various concentrations of iron dextran (100 mg to 300 mg total chronic dose administered), placebo treatment with saline, or no treatment at all (baseline).

RESULTS

Iron-loaded groups displayed dose-dependent depressions of heart rate, systolic pressure, developed pressure, coronary pressure, -dP/dt and +dP/dt, and increases in diastolic pressure. Monotonic dose-dependent increases in total heart aldehydes were observed in the iron-treated groups (r-0.97, p < 0.0001), whereas no significant differences were observed between baseline or time-placebo control groups.

CONCLUSIONS

While no single mechanism is likely to account for the complex pathophysiology of iron-induced heart failure, our findings show that chronic iron-loading in a murine model results in dose-dependent alterations to cardiac function; and results in free radical mediated damage to the heart, as measured by excess concentrations of cytotoxic aldehyde-derived peroxidation products. This is the first description of the effects of excess iron on cardiac function assessed by an ex-vivo Langendorff technique in a murine model of chronic iron-overload.

Association of common variants in/near six genes (ATP2B1, CSK, MTHFR, CYP17A1, STK39 and FGF5) with blood pressure/hypertension risk in Chinese children

Recent genome-wide association studies have identified several single-nucleotide polymorphisms (SNPs) that are associated with blood pressure (BP)/hypertension. In this study, we aimed to examine the established associations amongst Chinese children. We genotyped six SNPs (ATP2B1 rs17249754, CSK rs1378942, MTHFR rs1801133, CYP17A1 rs1004467, STK39 rs3754777 and FGF5 rs16998073) in Chinese children (N=3077, age range, 6-18 years). Based on the Chinese age- and sex-specific BP standards, 619 hypertensive cases and 2458 controls with normal BP were identified. Of the six SNPs, only ATP2B1 rs17249754 SNP was significantly associated with the risk of hypertension (allelic odds ratio (OR)=1.25, 95% confidence interval (CI): 1.08-1.44, P=0.003). Although all other SNPs showed a trend towards increasing the BP values and risk of hypertension, there was no statistically significant association after false discovery rate analysis. We calculated the weighted risk score using six SNPs, for systolic BP (SBP), diastolic BP (DBP) and hypertension. Each additional weighted risk score was associated with SBP by 1.18 mm Hg (95% CI=0.62-1.73, P<0.001), but not with the DBP (β=0.28, 95% CI=(-0.15)-0.74), and overall increased the risk of hypertension by 1.19-fold (95% CI=1.04-1.35, P=0.01). The present study confirmed the significant association of ATP2B1 rs17249754 with risk of hypertension among Chinese children, but failed to replicate the association of CSK rs1378942, MTHFR rs1801133, CYP17A1 rs1004467, STK39 rs3754777 and FGF5 rs16998073 with BP/risk of hypertension.

High-precision distribution of highly stable optical pulse trains with 8.8 × 10⁻¹⁹ instability

The high-precision distribution of optical pulse trains via fibre links has had a considerable impact in many fields. In most published work, the accuracy is still fundamentally limited by unavoidable noise sources, such as thermal and shot noise from conventional photodiodes and thermal noise from mixers. Here, we demonstrate a new high-precision timing distribution system that uses a highly precise phase detector to obviously reduce the effect of these limitations. Instead of using photodiodes and microwave mixers, we use several fibre Sagnac-loop-based optical-microwave phase detectors (OM-PDs) to achieve optical-electrical conversion and phase measurements, thereby suppressing the sources of noise and achieving ultra-high accuracy. The results of a distribution experiment using a 10-km fibre link indicate that our system exhibits a residual instability of 2.0 × 10⁻¹⁵ at1 s and8.8 × 10⁻¹⁹ at 40,000 s and an integrated timing jitter as low as 3.8 fs in a bandwidth of 1 Hz to 100 kHz. This low instability and timing jitter make it possible for our system to be used in the distribution of optical-clock signals or in applications that require extremely accurate frequency/time synchronisation.

Intrapericardial paclitaxel delivery inhibits neointimal proliferation and promotes arterial enlargement after porcine coronary overstretch

BACKGROUND

Catheter-based intrapericardial (IPC) delivery of therapeutic agents has recently been demonstrated. Paclitaxel is known to inhibit vascular smooth muscle cell proliferation. This study examined the effect of IPC instillation of paclitaxel on neointimal proliferation after balloon overstretch of porcine coronary arteries.

METHODS AND RESULTS

Overstretch injury of coronary arteries was followed by IPC administration of micellar paclitaxel at low dose (LD, 10 mg; n=6) or high dose (HD, 50 mg; n=7) or of control micelles (50 mg, n=5). Animals were euthanized 28 days after balloon dilation. Arterial injury indices were no different among the groups. The neointimal area, maximal intimal thickness, and adventitial thickness were significantly reduced in both LD (0.47+/-0.04 mm(2), 0.43+/-0.03 mm, and 0.35+/-0.02 mm, respectively) and HD (0.51+/-0.06 mm(2), 0.42+/-0.03 mm, and 0. 38+/-0.03 mm, respectively) paclitaxel groups compared with the control group (0.79+/-0.07 mm(2), 0.56+/-0.02 mm, and 0.47+/-0.02 mm, respectively; P:<0.001). Meanwhile, the vessel circumference measured at the external elastic lamina of paclitaxel-treated vessels was significantly larger than the control circumference. Apoptotic cells were found in the neointima. The apoptotic cell percentage was not different between the control (1.72%) and LD (2. 31%) groups but was higher in the HD group (7.07%, P:<0.0001 versus control and LD groups). Immunostaining for matrix metalloproteinase-2 revealed concurrent reduction in the HD group compared with the control and LD groups.

CONCLUSIONS

IPC space delivery of a single dose of paclitaxel significantly reduces vessel narrowing in this balloon-overstretch model. This effect is mediated by reduction of neointimal mass as well as positive vascular remodeling.

A biochemical, histochemical, and electron microscopic study on the effects of iron-loading on the hearts of mice

Acute iron poisoning and chronic iron overload are well-known causes of myocardial failure. Although the exact mechanism is not known, excess iron-catalyzed free radical generation is conjectured to play a role in damaging the myocardium and altering cardiac function. We report here on the effects of acute and chronic iron-loading on the total iron concentration, glutathione peroxidase activity, and cytotoxic aldehyde production in the heart of a murine model (n = 35). Light microscopic examination for the presence of ferrous and ferric iron was undertaken following histochemical staining for these species. In addition, examination of representative samples by transmission electron microscopy was performed. Our findings show that iron-loading can result in significant increases in total iron concentrations, alterations to glutathione peroxidase activity, and increases in cytotoxic aldehyde concentrations in the hearts of mice. Furthermore, we observe that iron-loading can significantly alter and damage various cellular constituents (e.g., mitochondria, lysosomes, sarcoplasmic reticulum) and this may have bearing on the mechanism of iron-induced heart failure.

Characterization of apoptotic macrophages in atheromatous tissue of humans and heritable hyperlipidemic rabbits

Apoptotic macrophages are regularly found in atherosclerotic plaques indicating programmed cell death as one of their regulatory controls. The objective of this study was to characterize in more detail apoptotic macrophages in atherosclerotic lesions of humans and heritable hyperlipidemic (HHL) rabbits. Macrophages were immunohistochemically analyzed using antibodies directed against alphaMbeta2-integrins (CD11b/CD18), CD44, major histocompatibility complex (MHC) class I and II, inducible nitric oxide synthase (iNOS), manganese superoxide dismutase (MnSOD), tumor necrosis factor alpha (TNFalpha), p53, c-jun/AP-1 and rabbit macrophages (RAM-11) and the TUNEL (TdT-mediated dUTP nick end labeling) technique. Colocalization studies of human atherosclerotic carotid and aortic tissue showed apoptotic plaque macrophages also being MnSOD-, alphaMbeta2-integrin-, CD44-, MHC class I- and II-, iNOS-, TNFalpha- and p53-immunoreactive. Similar results occurred in atherosclerotic aortas of HHL rabbits. Computer-assisted morphometric analyses revealed a positive correlation of the area density of MnSOD-immunoreactive macrophages with those of alphaMbeta2-integrin- and CD44-immunoreactive ones, but not with those of MHC class I- and II- as well as of RAM-11-immunoreactive macrophages. We conclude that apoptotic macrophages located in atherosclerotic vessel wall are activated, antigen-presenting, integrin-expressing and oxidatively stressed cells. Since all these processes have been demonstrated to cause apoptosis of macrophages in vitro, we propose their potency accelerates the susceptibility of the macrophages to programmed cell death in atherosclerotic lesions.

Population-based cohort study of variation in the use of emergency cholecystectomy for benign gallbladder diseases

Background

The aims of this prospective population-based cohort study were to identify the patient and hospital characteristics associated with emergency cholecystectomy, and the influences of these in determining variations between hospitals.

Methods

Data were collected for consecutive patients undergoing cholecystectomy in acute UK and Irish hospitals between 1 March and 1 May 2014. Potential explanatory variables influencing the performance of emergency cholecystectomy were analysed by means of multilevel, multivariable logistic regression modelling using a two-level hierarchical structure with patients (level 1) nested within hospitals (level 2).

Results

Data were collected on 4744 cholecystectomies from 165 hospitals. Increasing age, lower ASA fitness grade, biliary colic, the need for further imaging (magnetic retrograde cholangiopancreatography), endoscopic interventions (endoscopic retrograde cholangiopancreatography) and admission to a non-biliary centre significantly reduced the likelihood of an emergency cholecystectomy being performed. The multilevel model was used to calculate the probability of receiving an emergency cholecystectomy for a woman aged 40 years or over with an ASA grade of I or II and a BMI of at least 25·0 kg/m2, who presented with acute cholecystitis with an ultrasound scan showing a thick-walled gallbladder and a normal common bile duct. The mean predicted probability of receiving an emergency cholecystectomy was 0·52 (95 per cent c.i. 0·45 to 0·57). The predicted probabilities ranged from 0·02 to 0·95 across the 165 hospitals, demonstrating significant variation between hospitals.

Conclusion

Patients with similar characteristics presenting to different hospitals with acute gallbladder pathology do not receive comparable care.

Timing jitter characterization of mode-locked lasers with <1 zs/√Hz resolution using a simple optical heterodyne technique

Timing jitter characterization of free-running mode-locked lasers with an unprecedented resolution is demonstrated using an optical heterodyne technique. A highly sensitive timing jitter phase-discrimination signal with low-parasitic-amplitude sensitivity is achieved. Analytical and numerical methods are used to analyze the properties of the discrimination signal. For an experimental demonstration, we measure the timing jitter between two loosely synchronized mode-locked Er:Yb:glass lasers with 500-MHz fundamental repetition rates. The timing jitter-detection noise floor for a single mode-locked laser reaches 2.8×10(-13)  fs(2)/Hz (∼530  ys/√Hz), and the integrated timing jitter is 16.3 as from 10 kHz to the Nyquist frequency (250 MHz). These results show that this approach can be a simpler alternative to the well-established balanced optical cross-correlation technique.

The Pirh2-keratin 8/18 interaction modulates the cellular distribution of mitochondria and UV-induced apoptosis

Intermediate filaments (IFs) provide crucial structural support in higher eukaryotic cells. Accumulating evidences show that IFs also participate in various cellular activities including stress responses, cell growth, cell death and cell migration through dynamic interactions with various non-structure proteins. Here we report the identification of Pirh2, a RING-H2-type ubiquitin E3 ligase, as a novel binding partner of the cytoplasmic IF proteins keratin 8/18 (K8/18). Phosphorylation of either Pirh2 or K8/18 affects their association. Although Pirh2 was not found to influence the stability of K8/18, it displayed an unexpected role in regulating the organization of the network of K8/18 keratin filaments. Disruption of Pirh2-K8/K18 interaction by either UV irradiation or knockdown with Pirh2 or K18 led to the aggregation of K8/18 keratin filaments. It further induced mitochondrial redistribution, and this process is likely through a microtubule-mediated pathway. The abnormal localization of mitochondria in Pirh2-knockdown cells may partially account for its increased cell sensitivity to UV-induced apoptosis, probably through enhancing the release of pro-apoptotic proteins, such as cytochrome c and Smac/DIABLO to the cytosol. Overall, our data reveal the novel role of the Pirh2-K8/18 complex in governing the distribution of mitochondria.

Identification of the antibiotic ionomycin as an unexpected peroxisome proliferator-activated receptor γ (PPARγ) ligand with a unique binding mode and effective glucose-lowering activity in a mouse model of diabetes

AIMS/HYPOTHESIS

Existing thiazolidinedione (TZD) drugs for diabetes have severe side effects. The aim of this study is to develop alternative peroxisome proliferator-activated receptor γ (PPARγ) ligands that retain the benefits in improving insulin resistance but with reduced side effects.

METHODS

We used AlphaScreen assay to screen for new PPARγ ligands from compound libraries. In vitro biochemical binding affinity assay and in vivo cell-based reporter assay were used to validate ionomycin as a partial ligand of PPARγ. A mouse model of diabetes was used to assess the effects of ionomycin in improving insulin sensitivity. Crystal structure of PPARγ complexed with ionomycin revealed the unique binding mode of ionomycin, which elucidated the molecular mechanisms allowing the discrimination of ionomycin from TZDs.

RESULTS

We found that the antibiotic ionomycin is a novel modulating ligand for PPARγ. Both the transactivation and binding activity of PPARγ by ionomycin can be blocked by PPARγ specific antagonist GW9662. Ionomycin interacts with the PPARγ ligand-binding domain in a unique binding mode with properties and epitopes distinct from those of TZD drugs. Ionomycin treatment effectively improved hyperglycaemia and insulin resistance, but had reduced side effects compared with TZDs in the mouse model of diabetes. In addition, ionomycin effectively blocked the phosphorylation of PPARγ at Ser273 by cyclin-dependent kinase 5 both in vitro and in vivo.

CONCLUSIONS/INTERPRETATION

Our studies suggest that ionomycin may represent a unique template for designing novel PPARγ ligands with advantages over current TZD drugs.

Left Ventricular Energy Loss Assessed by Vector Flow Mapping in Patients with Prediabetes and Type 2 Diabetes Mellitus

The aim of this study was to assess left ventricular (LV) energy loss (EL) using vector flow mapping in patients with prediabetes (pre-DM) and type 2 diabetes mellitus (DM). Thirty pre-DM patients, 51 DM patients, and 38 controls were studied by transthoracic echocardiography. EL-total, EL-base, EL-mid and EL-apex climaxed at different phases. Compared with controls, pre-DM and DM patients showed increased EL-total during slow ejection, isovolumic relaxation, rapid filling and slow filling (p < 0.05). Similarly, EL-base, EL-mid and EL-apex increased during certain phases. Stepwise multiple regression analysis revealed that the early transmitral valve blood flow velocity E, the late transmitral valve blood flow velocity A, the ratio of E/A, LV peak torsion, diastolic untwisting velocity, vortex circulation and area were independently associated with EL during different phases (all p < 0.05). Our study suggests that LV EL is increased during diastole and certain phases of systole in DM patients compared with controls. The changes in LV vortex and deformation mechanics were correlated with EL.

Highly stable wideband microwave extraction by synchronizing widely tunable optoelectronic oscillator with optical frequency comb

Optical frequency combs (OFCs), based on mode-locked lasers (MLLs), have attracted considerable attention in many fields over recent years. Among the applications of OFCs, one of the most challenging works is the extraction of a highly stable microwave with low phase noise. Many synchronisation schemes have been exploited to synchronise an electronic oscillator with the pulse train from a MLL, helping to extract an ultra-stable microwave. Here, we demonstrate novel wideband microwave extraction from a stable OFC by synchronising a single widely tunable optoelectronic oscillator (OEO) with an OFC at different harmonic frequencies, using an optical phase detection technique. The tunable range of the proposed microwave extraction extends from 2 GHz to 4 GHz, and in a long-term synchronisation experiment over 12 hours, the proposed synchronisation scheme provided a rms timing drift of 18 fs and frequency instabilities at 1.2 × 10⁻¹⁵/1 s and 2.2 × 10⁻¹⁸/10000 s.

Associations of obesity susceptibility loci with hypertension in Chinese children

CONTEXT

Recent genome-wide association studies have identified several single-nucleotide polymorphisms (SNPs) that are associated with body mass index (BMI)/obesity.

OBJECTIVE

As obesity is an independent risk factor for hypertension, the objective of the study was to investigate the associations of obesity susceptibility loci with blood pressure (BP)/hypertension in a population of Chinese children.

DESIGN, SETTING AND PARTICIPANTS

This was a genotype-phenotype association study. Participants included 3077 Chinese children, aged 6-18 years. Based on the Chinese age- and sex-specific BP standards, 619 hypertensive cases and 2458 controls with normal BP were identified.

MAIN OUTCOME MEASURES

BP was measured by auscultation using a standard clinical sphygmomanometer.

RESULTS

Of the 11 SNPs, only FTO rs9939609 was significantly associated with systolic BP (SBP; P=0.034) and three SNPs were significantly associated with diastolic BP (DBP; GNPDA2 rs10938397: P=0.026; FAIM2 rs7138803: P=0.015; NPC1 rs1805081: P=0.031) after adjustment for age, sex and hypertension status. In addition, three SNPs were significantly associated with hypertension risk after adjustment for age and sex (FTO rs9939609: odds ratio (OR)=1.35, 95% confidence interval (CI) 1.12-1.62, P=0.001; MC4R rs17782313: OR=1.22, 95% CI 1.06-1.42, P=0.007; GNPDA2 rs10938397: OR=1.17, 95% CI 1.02-1.34, P=0.021). After additional adjustment for BMI, none remained significant. The genetic risk score (GRS), based on three significant SNPs (FTO rs9939609, MC4R rs17782313, GNPDA2 rs10938397), showed a positive association with SBP (P=5.17 × 10(-4)) and risk of hypertension (OR=1.22, 95% CI 1.12-1.33, P=6.07 × 10(-6)). Further adjustment for BMI abolished the positive associations (SBP: P=0.220; DBP: P=0.305; hypertension: P=0.052). Only FTO rs9939609 and GRS were statistically associated with hypertension risk in the age- and sex-adjusted model after correction for multiple testing.

CONCLUSIONS

The present study demonstrated that FTO rs9939609 and combined SNPs were significantly associated with risk of hypertension, which seems to be dependent on BMI.

Early Detection of Left Atrial Energy Loss and Mechanics Abnormalities in Diabetic Patients with Normal Left Atrial Size: A Study Combining Vector Flow Mapping and Tissue Tracking Echocardiography

Background

Whether left atrial (LA) functional abnormalities already exist when the LA is of normal size is unknown. The aim of this study was to explore LA energy loss and mechanics changes using vector flow mapping (VFM) and two-dimensional tissue tracking (2DTT) echocardiography in patients with diabetes and normal LA size.

Material/Methods

This study included 47 normotensive patients with diabetes and 45 controls. The following indexes were measured: LA energy loss during systole (LAELs), early diastole (LAELed), and atrial contraction (LAELac); atrial longitudinal strain during systole (SLAs), early diastole (SLAed) and late diastole (SLAac); and peak LA strain rate during systole (SRLAs), early diastole (SRLAed), and atrial contraction (SRLAac).

Results

The LAELs and LAELed decreased in diabetic patients compared with controls (P=0.002, P<0.01, respectively), whereas the LAELac increased in diabetic patients (P<0.001). The SLAs, SLAed, SRLAs, and SRLAed (all P<0.01) were all lower in diabetic patients than in controls. However, there was no difference in the SLAac and SRLAac between the two groups. Multivariate regression analysis showed that the LAELs, LAELac, and SRLAs were independently associated with HbA_1c in the whole study population.

Conclusions

LA energy loss and deformation mechanics are already impaired in diabetic patients with normal LA size and the long-term parameter of glycemic control was correlated with them. VFM combined with 2DTT might be a promising tool for the early detection of LA dysfunction caused by impaired glucose metabolism.