Determination of delay time in individual transfer function for central aortic pressure reconstruction

In previous research,time-delay(Δt)was a more important parameter than the reflection coefficient in the individual transfer function of central aortic pressure reconstruction.TheΔt can be obtained by electrocardiography(ECG)or phonocardiography(PCG).Because the pre-ejection period remains an uncertain factor,the present study used ECG and PCG to define the delay time and analyzed the accuracy of the reconstruction results.TheΔtpre is the actual delay time derived from the aorta to the carotid pressure wave,ΔtPCG is the time delay between the aortic valve component of the second heart sound and the dicrotic incisura of the carotid pressure wave,andΔtECG represents the delay from the interval of the ECG R-peak to the foot of the carotid pressure wave.Compared with the measured aortic pressure,the reconstruction result obtained byΔt=ΔtPCG slightly differed from the best result estimated byΔt=Δtpre.However,the differences between the result obtained byΔt=ΔtECG and the best result were significant in terms of the diastolic blood pressure,and pulse pressure,and especially in terms of the augmentation index and root-mean-square-error.Thus,theΔt should be determined by PCG for central aortic pressure reconstruction in practice.     

The Early Variation of Left Ventricular Strain after Aortic Valve Replacement by Three-Dimensional Echocardiography

Aortic stenosis (AS) and aortic incompetence (AI) are common aortic valve diseases. Both may deteriorate into irreversible myocardial dysfunction and will increase the risk of sudden death. In this study, we aimed to investigate the early variation trend of left ventricular function by three-dimensional speckle tracking echocardiography (3D-STE) in the patients who underwent cardiac surgeries for aortic valve disease. Twenty patients with severe aortic AS and 16 patients with severe AI were enrolled. All of them underwent the aortic valve replacement (AVR) procedures. The patients’ global longitudinal strain (GLS) and global circumferential strain (GCS) were evaluated by 3D-STE before surgery and at 1 week after surgery. In addition, GLS and GCS were followed at 1 month as well as 3 months after AVR. In AS patients, the GCS after AVR altered little both at 1 week (p = 0.562) and at 1 month (p = 0.953) compared with the data before the surgery. And it increased significantly at 3 months of follow-up observation compared to that before AVR (p<0.05). Meanwhile, GLS increased progressively after AVR and improved significantly at 3 months after surgery (p<0.05). For the AI patients, GLS as well as GCS decreased at 1 week after AVR compared to those data at baseline (p<0.05). However, these two parameters recovered at 1 month after AVR. Furthermore, GLS and GCS improved significantly at 3 months after the surgery (p<0.05). Therefore, both GLS and GCS were influenced by AVR and would be improved at 3 months after surgery both in AS patients or AI patients. GLS and GCS can be finely evaluated by 3D-STE, and they are helpful to determine the variation tendency of left ventricular function in patients with AVR.     

Characterization and stress-protective action of <Emphasis Type="Italic">Saccharomyces cerevisiae</Emphasis> extracellular peptide factors on propionic acid bacteria

Protective effect of Saccharomyces cerevisiae exometabolites (RF₁ and RF₂) on seven strains of propionic acid bacteria under exposure to bile salts and acid stress was studied. RF₂ had a stronger protective effect than RF₁. Comparison of the analytical profiles of RF₁ and RF₂, separated by RP-HPLC, showed that nearly 80% of RF₁ components were present in RF₂. Separation of S. cerevisiae RF₁ into individual components by means of semi-preparative RP-HPLC was used for structural characterization of the active component of the RF₁ fraction. It was found to contain two pentapeptides (<1 kDa) with identical amino acid sequences (¹Gly-Pro-Tre-Gly-Pro⁵), differing in one hexose residue. The RF₂ separation method based on three-stage liquid chromatography at low and high pressure was developed, which involved analytical high-pressure gel chromatography. The use of the latter method made it possible to separate high-molecular components and perform enrichment of low-molecular peptides. Peptide origin of the RF₂ active substances with molecular masses allegedly below 300 Da was confirmed.     

Hypoxemia increases renin secretion rate in anesthetized newborn lambs

The response of renin secretion rate (RSR) to acute systemic hypoxemia (mean arterial p0₂ 34±8 torr) was studied in mechanically ventilated, anesthetized newborn lambs 5–10 days of age (n=6). Ventilation of these lambs with room air (normoxemia) was followed by administration of low oxygen inhaled gas mixture (f_i0₂ 0.11) which was associated with no change in arterial pC0₂, pH, mean arterial pressure (MAP), renal blood flow (RBF, measured by electromagnetic flow probe), and calculated renal vascular resistance (RVR). Arterial plasma renin activity (PRA_A 4.28±1.73 to 6.46±3.00 ng AI/ml · hr), renal vein plasma renin activity (PRA_RV, 6.26±3.79 to 11.44±7.11 ng AI/ml · hr) and renin secretion rate (RSR, 19.86±21.70 to 51.32±48.54 units/min · KgBW) increased significantly (p<0.05) in response to hypoxemia. Restoration of normoxemia (arterial p0₂ 100±18 torr) was associated with significant decline in MAP (to 65±14 mmHg) and RBF (to 9.0±2.1 ml/min · KgBW) and further increases in PRA_A (to 8.98±3.40 ng AI/ml · hr), PRA_RV (to 19.04±10.62 ng AI/ml · hr) and RSR (to 88.6±77.6 units/min · KgBW). PRA_A correlated strongly with PRA_RV (r=0.84) and RSR (r=0.60) in these lambs. These results suggest that PRA_A, PRA_RV and RSR increase in response to hypoxemia in anesthetized lambs by a mechanism other than renal arterial baroreceptor stimulation, although this mechanism may be active during recovery from hypoxemia. Furthermore, PRA_A closely approximates RSR in newborn lambs under these conditions.     

Quantitative estimates of steric effects: Intramolecular strain energy effects on the activation energy for aquation of some trans-dichlorotetraaminecobalt(III) complexes

In an effort to quantitatively estimate steric contributions to the aquation rates of a series of structurally related cobalt(III) tetraamine complexes, strain energy minimization calculations have been performed on the reactant and some plausible transition state structures. Free energies of activation ΔG*_obs, are factored as: ΔG*_obs, = ΔG*_bb + ΔG*_strain + Δ_G*_CF + ΔG*_solvation + … where ΔG*_bb is the free energy change associated with bond breaking, ΔG*_solvation is the solvation free energy difference between the reactant and a proposed transition stare, ΔG*_CF is the difference in crystal field stabilization between the reactant and a proposed transition state, and ΔG*_strain is the strain energy difference between the reactant complex and a proposed transition state. The activation energy for the aquation of a hypothetical ‘strain free’ complex is defined as ΔG*_int and reflects the energy required for the bond breaking step with all other terms. For the cations trans-(RR,SS)-dichloro-1,8- diamino-3,6-diazaoctanecobalt(III)(trans [Co(2,2,2- tet)Cl₂]⁺), trans-(RR,SS)- or trans-(RS)-dichloro-1.9- diamino-3,7-diazanonanecobalt(III)(trans [Co(2,3,2- tet)Cl₂]⁺ and trans-(RS)-dichloro-1,10-diamino-4,7- diazadecanecobalt(III)(trans[Co(3,2,3-tet)Cl₂]⁺) ΔG*_int is found to be a constant 123 kJ/mol. For the trans-dichlorocobalt(III) complexes with the ligands 1,4,7,10-tetraazacyclotridecane([13]-ane-N₄), 1,4,8, 11-tetraazacyclotetradecane([14]-ane-N₄), 1,4,8,12- tetraazacyclopentadecane([15]-ane-N₄) and 1,5,9,13- tetraazacyclohexadecane([16]-ane-N₄), ΔG*_int lies in the range 133–139 kJ/mol.     

Atrial natriuretic peptide messenger RNA and peptide in rats with aortic valve insufficiency

To investigate ANP gene expression in diseased hearts of animals without genetic defects, immunoreactive ANP (IR-ANP) and ANP mRNA were measured in a rat with aortic valve insufficiency (AI), which was produced by puncturing one of the aortic valve leaflets with a plastic rod. Plasma IR-ANP concentration was higher in AI rats than in sham rats (p less than 0.05). Decreased atrial concentration of IR-ANP (p less than 0.05) and unchanged atrial ANP mRNA concentration were shown in AI rats. The ventricular concentrations of IR-ANP and ANP mRNA in AI rats were 5.4 and 2.4 times higher than those in sham rats (p less than 0.05, respectively). These results demonstrate that gene expression of ventricular ANP is markedly increased in AI rats while that of atrial ANP is not changed.     

Protocol for Relative Hydrodynamic Assessment of Tri-leaflet Polymer Valves

Limitations of currently available prosthetic valves, xenografts, and homografts have prompted a recent resurgence of developments in the area of tri-leaflet polymer valve prostheses. However, identification of a protocol for initial assessment of polymer valve hydrodynamic functionality is paramount during the early stages of the design process. Traditional in vitro pulse duplicator systems are not configured to accommodate flexible tri-leaflet materials; in addition, assessment of polymer valve functionality needs to be made in a relative context to native and prosthetic heart valves under identical test conditions so that variability in measurements from different instruments can be avoided. Accordingly, we conducted hydrodynamic assessment of i) native (n = 4, mean diameter, D = 20 mm), ii) bi-leaflet mechanical (n= 2, D = 23 mm) and iii) polymer valves (n = 5, D = 22 mm) via the use of a commercially available pulse duplicator system (ViVitro Labs Inc, Victoria, BC) that was modified to accommodate tri-leaflet valve geometries. Tri-leaflet silicone valves developed at the University of Florida comprised the polymer valve group. A mixture in the ratio of 35:65 glycerin to water was used to mimic blood physical properties. Instantaneous flow rate was measured at the interface of the left ventricle and aortic units while pressure was recorded at the ventricular and aortic positions. Bi-leaflet and native valve data from the literature was used to validate flow and pressure readings. The following hydrodynamic metrics were reported: forward flow pressure drop, aortic root mean square forward flow rate, aortic closing, leakage and regurgitant volume, transaortic closing, leakage, and total energy losses. Representative results indicated that hydrodynamic metrics from the three valve groups could be successfully obtained by incorporating a custom-built assembly into a commercially available pulse duplicator system and subsequently, objectively compared to provide insights on functional aspects of polymer valve design.     

孕中晚期胎儿主动脉弓狭窄的超声诊断参数分析及其影响因素分析

摘要 目的：探究孕中晚期胎儿主动脉弓狭窄的超声诊断参数分析,并就超声诊断参数对孕中晚期胎儿主动脉弓狭窄的影响因素开展分析。方法：选择2020年7月至2021年7月于我院就诊后被确诊为孕中晚期主动脉弓狭窄的40例胎儿为狭窄组,另取同期体格检查正常的40例胎儿为对照组,以胎儿出生后超声心动图检测或尸检结果为金标准,比较两组胎儿超声指标Z-分数（AI Z-score）、升主动脉Z-分数（AO Z-score）、主动脉峡部/升主动脉（AI/AO）差异,分别绘制AI Z-score、AO Z-score以及AI/AO对孕中晚期胎儿主动脉弓狭窄的诊断ROC曲线,并计算其曲线下面积（AUC）,最后采用Logistic回归分析的方式计算孕中晚期胎儿主动脉弓狭窄影响因素。结果：（1）窄缩组胎儿的超声参数AI Z-score、AO Z-score以及AI/AO均明显低于对照组（P<0.05）;（2）AI/AO为孕中晚期胎儿主动脉弓狭窄的危险因素（P<0.05）;（3）AI Z-score、AO Z-score、AI/AO以及联合检测对胎儿主动脉弓狭窄的诊断AUC分别为0.801（95% CI=0.691-0.910,P<0.001）、0.835（95% CI=0.739-0.932,P<0.001）、0.843（95% CI=0.757-0.929,P<0.001）、0.920（95% CI=0.865-0.975,P<0.001）,截断值分别为-1.64、-1.47和0.535,诊断灵敏度和特异度分别为72.50%和72.50%、77.50%和77.50%、75.00%和80.00%、85.00%和82.50%。结论：超声诊断对孕中晚期胎儿主动脉弓狭窄具有较好的诊断价值,其指标AI Z-score、AO Z-score、AI/AO能够量化分析孕中晚期胎儿主动脉弓狭窄风险,可以考虑将其应用于临床中。     

抗吡虫啉棉蚜种群对吡蚜酮等药剂的交互抗性及施药对其生物学特性的影响

为了明确吡蚜酮对抗吡虫啉棉蚜Aphis gossypii种群的防治效果,提出抗吡虫啉棉蚜的治理策略,利用抗吡虫啉棉蚜种群(RF₂₇)、敏感种群(SS)和夏津田间种群(XJ),分别采用浸渍法、微量点滴法、生化测定法和系统观察法研究了棉蚜无翅成蚜对吡蚜酮等药剂的交互抗性及施药对其生物学特性的影响。结果表明: 吡蚜酮对RF₂₇,XJ和SS的LD₅₀分别为1.213×10^-5,8.506×10^-5和5.140×10^-5 μg/头,RF₂₇对吡蚜酮表现出明显的负交互抗性现象。RF₂₇对啶虫脒、烯啶虫胺和噻嗪酮分别产生2.35,2.98和1.71倍的抗性。RF₂₇的羧酸酯酶和谷胱甘肽-S-转移酶的比活力较SS分别高2.73和1.57倍,说明羧酸酯酶和谷胱甘肽-S-转移酶比活力的提高是引起棉蚜对吡虫啉产生抗性的重要原因之一。吡蚜酮分别处理RF₂₇,XJ和SS,其羧酸酯酶和谷胱甘肽-S-转移酶均受到显著抑制。吡蚜酮以低剂量处理RF₂₇成蚜,对其生长发育有显著的不利影响,表现为若蚜存活率降低(64.60%),净生殖率降低（10.39）,内禀增长率和周限增长率显著降低(分别为0.21和1.23),世代历期延长（10.87 d）,相对适合度较小（仅为0.70）。这些结果表明吡蚜酮在棉蚜防治中具有很高的应用价值。     

The Estimation of Aortic Insufficiency

Thirty patients were investigated to determine the degree of aortic insufficiency present in them, using the test of Braunwald and Morrow in which indicator dye is injected at descending levels in the aorta and regurgitant dye is recorded by oximetry at the right ear. In the presence of aortic insufficiency regurgitant dye was demonstrated from as low as the second lumbar level, while in normal subjects none was demonstrated on injection distal to the fifth thoracic level. In the older patients the level was more proximal than in the younger for similar regurgitant flows. In most patients the test correlated well with the clinical impression of the severity of the lesion. However, tachycardia, bradycardia a reduced forward flow secondary to failure, aortic stenosis, or mitral stenosis or insufficiency will modify the level from which regurgitation occurs. Estimation of forward flow would permit estimation of the percentage regurgitation and allow a more accurate assessment of aortic insufficiency. Preoperative and postoperative estimation permitted objective assessment of successful corrective surgery.     

Pulsatile shear stress increased mitochondrial membrane potential: Implication of Mn-SOD

Mitochondrial dysfunction is intimately involved in cardiovascular diseases. Mitochondrial membrane potential (ΔΨ_m) is coupled with oxidative phosphorylation to drive ATP synthesis. In this study, we examined the effect of physiological pulsatile shear stress (PSS) on ΔΨ_m and the role of Mn-SOD expression on ΔΨ_m. Confluent human aortic endothelial cells (HAEC) were exposed to PSS, and ΔΨ_m was monitored using tetramethylrhodamine methyl ester (TMRM⁺), a mitochondrial membrane potential probe. PSS significantly increased ΔΨ_m and the change in ΔΨ_m was a dynamic process. ΔΨ_m returned to baseline level after PSS for 2 h followed by static state for 4 h. Mitochondrial Mn-SOD expression and activities were also significantly up-regulated in response to PSS. Silencing Mn-SOD attenuated PSS-mediated ΔΨ_m increase while adding Mn-SOD mimetic, MnTMPyP, increased ΔΨ_m to the similar extent as induced by PSS. Our findings suggest that PSS-increased mitochondrial ΔΨ_m, in part, via Mn-SOD up-regulation.     

Percutaneous implantation of the CoreValve aortic valve prosthesis in patients at high risk or rejected for surgical valve replacement: Clinical evaluation and feasibility of the procedure in the first 30 patients in the AMC-UvA

Objective. To report the feasibility, safety and efficacy of percutaneous aortic valve implantation (PAVI) with the CoreValve self-expanding aortic valve bioprosthesis in elderly patients with aortic valve stenosis who are rejected for surgery or have a high surgical risk.Methods. PAVI using the CoreValve ReValving System was performed under general anaesthesia in 30 high-risk (surgical) patients with a symptomatic severe aortic valve stenosis.Results. The patients had a mean age of 80.5±7.7 years, a mean aortic valve area of 0.71±0.19 cm², a peak transvalvular aortic gradient of 79±25 mmHg, as measured with echo Doppler, a logistic EuroSCORE of 15±10% and a Society of Thoracic Surgeons (STS) score of 5.2±2.9%. Device success was achieved in all patients and acute procedural success in 27 patients (90%). In the surviving patients, there was in a reduction of the peak aortic pressure gradient from 76±24 mmHg to 22±7 mmHg (n=24, p<0.00001) 30 days after successful device implantation. At 30 days, major adverse cardiovascular and cerebral events had occurred in seven patients (23%). This included mortality in six patients (20%), of which one death was cardiovascular. The other five non-cardiovascular deaths involved two patients who died of an exacerbation of severe pre-existent pulmonary disease and three of infectious complications.Conclusions. Percutaneous aortic valve implantation was successfully performed in our centre in highrisk patients, with a 30-day mortality of 20%. When successful, marked haemodynamic improvement and relief of symptoms was achieved. (Neth Heart J 2010;18:18-24.)     

Genome-wide association studies for sperm traits in Assaf sheep breed

Sperm quality traits routinely collected by artificial insemination (AI) center for rams progeny test are related with the capacity to produce sperm doses for AI and, in more or less grade, with males' fertility. Low-quality ejaculates are unuseful to perform AI sperm doses, which suppose high economic loses for the AI center. Moreover, sperm quality traits have low heritability values which make traditional genetic selection little efficient to its improvement. In this work, a genome-wide association study (GWAS) was conducted by using sperm quality traits data and 50 K Affymetrix custom chip genotypes of 429 rams of Assaf breed from OVIGEN AI centre. Furthermore, 47 of these rams were also genotyped with the Illumina HD Ovine BeadChip, and therefore HD genotypes were imputed for all rams with phenotype data. Previous to the GWAS, a linear regression model was fitted including sperm traits as dependent variables; the flock of origin, date of sperm collection, and jump number as fixed effects; rams age at collection in months as covariate; and ram permanent effect as random. Pseudo-phenotypes obtained from this model were used as input for GWAS. Associations at the chromosome-wise level (FDR 10%) of 76 single-nucleotide polymorphisms (SNPs) in 4 chromosomes for ejaculate concentration (CON), 20 SNPs in 3 chromosomes for ejaculate volume (VOL), 32 SNPs in 1 chromosome for ejaculate number of spermatozoa (SPZ), and 23 SNPs for spermatozoa mass motility (MOT) in 17 chromosomes were found. Only SNPs associated with MOT overcame the genome-wide significance level. Some candidate genes for sperm traits variability were SLC9C1 (OAR1), TSN (OAR2), and FUT10 (OAR26) for MOT;. DOCK2, CPLANE1, SPEF2, and RAI14 (OAR16) for CON; SCAPER and PSMA4 (OAR18) for VOL; and PARM1 and LOC101110593 (OAR6) for SPZ. SNPs associated with sperm traits were not found to be correlated with milk production genetic variation; however, the high frequencies of some SNPs with negative effect over sperm traits found in animals at the top milk yield estimated breeding values (EBVs) ranking would allow to exert some selective presure to improve rams sperm performances. Effects and frequencies of some of the SNPs detected over sperm quality traits make these variants good candidates to be used in marker-assisted selection to improve sperm characteristics of Assaf rams and AI center efficiency to produce sperm doses.     

Recommended Criteria for Cardiac Catheterization in Patients with Aortic Valve Disease

Criteria for selection of patients with aortic valve disease for cardiac catheterization are described, based on a study of 81 cases. Children with aortic stenosis warrant catheterization at the time when the clinical diagnosis is made, but in adults this examination may be deferred until symptoms appear or left ventricular hypertrophy is recognized. In patients with pure aortic insufficiency catheterization may be deferred until symptoms appear. When severe stenosis and insufficiency co-exist, the valve is usually heavily calcified. Thirty-seven per cent of patients with aortic valve disease have co-existing mitral lesions and these patients are usually women, are fibrillating and, as a rule, have atrial enlargement in contrast to those with aortic valve disease only. On rare occasions, patients with mitral valve disease have clinically silent but angiographically demonstrable aortic insufficiency; therefore, aortography should precede open-heart correction of a mitral lesion so as to detect minor degrees of aortic insufficiency.     

Determination of melting temperature and temperature melting range for DNA with multi-peak differential melting curves

Many factors that change the temperature position and interval of the DNA helix–coil transition often also alter the shape of multi-peak differential melting curves (DMCs). For DNAs with a multi-peak DMC, there is no agreement on the most useful definition for the melting temperature, T_m, and temperature melting width, ΔT, of the entire DNA transition. Changes in T_m and ΔT can reflect unstable variation of the shape of the DMC as well as alterations in DNA thermal stability and heterogeneity. Here, experiments and computer modeling for DNA multi-peak DMCs varying under different factors allowed testing of several methods of defining T_m and ΔT. Indeed, some of the methods give unreasonable “jagged” T_m and ΔT dependences on varying relative concentration of DNA chemical modifications (r_b), [Na⁺], and GC content. At the same time, T_m determined as the helix–coil transition average temperature, and ΔT, which is proportional to the average absolute temperature deviation from this temperature, are suitable to characterize multi-peak DMCs. They give smoothly varying theoretical and experimental dependences of T_m and ΔT on r_b, [Na⁺], and GC content. For multi-peak DMCs, T_m value determined in this way is the closest to the thermodynamic melting temperature (the helix–coil transition enthalpy/entropy ratio).     

Prevalence of Valvular Heart Disease in A Cohort of Patients Taking Cabergoline for Management of Hyperprolactinemia

ObjectiveTo determine the prevalence of valvular heart disease in a cohort of patients taking cabergoline for the management of hyperprolactinemia.MethodsA retrospective review of medical records identified patients with hyperprolactinemia who underwent evaluation at Vanderbilt University Medical Center between January and June 2007. The medical records of those patients who were prescribed cabergoline and who underwent elective echocardiography were reviewed for details pertaining to cardiac valvular abnormalities and cabergoline use.ResultsForty-five patients (mean age, 41 ± 10 years [SD]) taking 0.91 ± 0.96 mg of cabergoline per week for a mean duration of 39 ± 29 months underwent echocardiography. Abnormalities of the cardiac valves were present in 3 patients (7%): 1 patient exhibited mild mitral regurgitation, 1 patient had focal aortic valve thickening, and 1 patient demonstrated mitral valve thickening. We found no significant difference in either the cumulative dose of cabergoline (P = .800) or the duration of cabergoline therapy (P = .745) between those patients with and those without these echocardiographic abnormalities.ConclusionWe found echocardiographic valve abnormalities in 3 of 45 patients (7 %) who had been prescribed cabergoline for the management of hyperprolactinemia. This prevalence of valvular heart disease after approximately 3 years of cabergoline treatment is no different from that previously reported in normal populations as determined by echocardiography. (Endocr Pract. 2008;14:672-677)     

Relationship of respiration to body weight in the tilapia Oreochromis niloticus under resting and normoxic conditions

• 1.1. The relationships of oxygen consumption (V_o2, ml/min/fish), ventilation volume (V_g, ml/min/fish), stroke volume (V_s, ml/stroke/fish), respiration frequency (RF, stroke/min) and oxygen utilization (U, %) to body weight (W, g) in the tilapia under resting and normoxic conditions were V_o2 = 0.002835W^0.754193, V_g = 0.688965W^0.722786, V_s = 0.002790W^1.017188, RF = 248.58210W^−0.296139, U = 0.000935W + 87.394288, respectively.

     

Comparison of mtDNA Variants Among Mediterranean and New World Introductions of the Mediterranean Fruit Fly Ceratitis capitata (Wied.)

Restriction enzyme cleavage sites of mitochondrial DNA (mtDNA) from the Mediterranean fruit fly (Ceratitis capitata) were found to vary among Mediterranean and New World populations. A restriction map for six populations (one from Greece and five from the New World) is constructed for the Mediterranean fruit fly. Six diagnostic restriction enzymes (EcoRI, EcoRV, HaeIII, HindIII, SstI, XbaI) are assigned three geographically distinct main types, CI, CII, and CIII.