[The success rate of His-Purkinje system pacing in patients with various sites of atrioventricular block].

Objective: To evaluate the success rate of His-Purkinje system pacing (HPSP) in patients with various sites of atrioventricular block (AVB) and provide clinical evidence for the selection of HPSP in patients with AVB. Methods: This is a retrospective case analysis. 637 patients with AVB who underwent permanent cardiac pacemaker implantation and requiring high proportion of ventricular pacing from March 2016 to September 2021 in the Department of Cardiology, General Hospital of Northern Theater Command were enrolled. The site of AVB was determined by electrophysiological examination. His bundle pacing (HBP) was performed in the first 130 patients (20.4%) who were classified as the HBP group and HPSP included HBP and/or left bundle branch pacing (LBBP) was performed in later 507 patients (79.6%) and these patients were classified as the HPSP group. The basic clinical information such as age and sex of the two groups was compared, and the success rates of HBP or HPSP in patients with different sites of AVB and QRS intervals were analyzed. Results: The age of HBP group was (66.4±15.9) years with 75 males (57.7%). The age of HPSP group was (66.8±13.6) years with 288 (56.8%) males. Among 637 patients, 63.0% (401/637) had atrioventricular node block; 22.9% (146/637) had intra-His block; 14.1% (90/637) had distal or inferior His bundle block. Totally, the success rate of HPSP was higher than that of HBP [93.9% (476/507) vs. 86.9% (113/130), P<0.05]. In each group of patients with various AVB sites, the success rate of HPSP was higher than that of HBP respectively and both success rates of HBP and HPSP showed a declining trend with the distant AVB site. The success rate of HBP in patients with atrioventricular node block and intra-His block was higher than that in patients with distal or inferior His bundle block [95.2% (79/83) vs. 47.1% (8/17), P<0.001; 86.7% (26/30) vs. 47.1% (8/17), P=0.010]. The success rate of HPSP was higher than that of HBP in patients with distal or inferior His bundle block [87.7% (64/73) vs 47.1% (8/17), P=0.001]. In patients with QRS<120 ms, 94.9% (520/548) of AVB sites were in atrioventricular node or intra-His, and HBP had a similar high success rate with HPSP [95.6% (109/114) vs. 96.3% (418/434), P=0.943] in these patients. In patients with QRS ≥ 120 ms, 69.7% (62/89) of AVB sites were at distal or inferior His bundle, and the success rate of HBP was only 25.0% (4/16), while the success rate of HPSP was as high as 79.5% (58/73), P<0.001. Conclusions: In patients with QRS<120 ms and atrioventricular node block or intra-His block, success rates of HBP and HPSP are similarly high and HBP might be considered as the first choice. In patients with QRS ≥ 120 ms and AVB site at distal or inferior His bundle, the success rate of HPSP is higher than that of HBP, suggesting LBBP should be considered as the first-line treatment option.

[Correlation analysis of cervical spine dysfunction, pain and muscle strength in office workers].

Objective: To expore the correlation between neck disability, neck pain and muscle strength in cervical pondylosis of office worker, and to provide scientific basis for the prevention and treatment of cervical spondylosis. Methods: In April 2021 ,234 patients with cervical spondylotic myelopathy treated in the Subsidiary Rehabilitation Hospital of Fujian University of Traditional Chinese Medicine from April 2015 to April 2017 were selected, the correlation between Neck Disability Index (NDI) score, neck pain and muscle strength was analyzed using the Spearman rank correlation method. Mann-Whitney U test was used to compare the difference of maximum muscle strength of isometric contraction. Results: NDI score was negatively correlated with neck flexion, extension, and muscle strength in the left and right flexion directions (r(s)=-0.164, -0.169, -0.222, -0.176, P=0.012, 0.010, 0.001 , 0.007). In mild and moderate functional disorder patients, the muscle strength in flexion, extension and left and right flexion direction was greater, the difference was statistically significant (P <0.01). Conclusion: There is a negative correlation between cervical functional disorder and cervical muscle strength in office workers, suggesting that strengthening cervical muscle strength may be a way to improve cervical spine function.

[Application and efficacy of the adjustment on left ventricular electrical delay and the distance between right and left ventricular pacing polar in optimizing the left ventricular pacing polar].

Objective: To investigate the application and efficacy of left ventricular (LV) electrical delay (LVED) and the distance of right ventricular(RV) pacing polar to LV(DRLV) in optimizing LV pacing polar. Methods: Heart failure (HF) patients who implanted cardiac resynchronization therapy (CRT) device with a LV quadripolar lead from January 2014 to January 2018 at General Hospital of Northern Theater Command were enrolled in the study. Measurements of LVED and DRLV of each polar of the lead were performed in patients with HF who underwent CRT with LV quadripolar lead. The principle in turn for polar selecting used for clinical LV pacing was the pacing polar: (1)without phrenic nerve stimulation(PNS); (2)with appropriate capture threshold; (3)not located in apical; (4)with maximal LVED; (5)with maximal DRLV. The LV pacing polar was selected for CRT according to the procedure. The distribution of target veins implanted with LV quadripolar lead were calculated. The percentage of biventricular pacing at 6-month follow-up was recorded. The following indexes were compared before and 6-month after surgery, including QRS duration, LV end-systolic volume(LVESV), LV ejection fraction(LVEF), LV end-diastolic dimension(LVEDD), 6 minute walking distance(6MWD), New York Heart Association(NYHA) class. The efficacy and echocardiographic efficacy of CRT was evaluated. Results: There were twenty-nine HF patients enrolled. The mean age of enrolled patients was(61.7±7.6)years old, nineteen (66%)of them were male. There were seventeen(59%) patients diagnosed as dilated cardiomyopathy and twelve(41%) patients as ischemic cardiomyopathy. All patients were successfully implanted with LV quadripolar lead into target veins, and all four pacing sites were also in target veins. Target veins were located in lateral veins in 15 patients (52%), anterior veins in 2 patients (7%), posterior veins in 11 patients (38%), and lateral branches of great cardiac veins in 1 patient (3%). After 6-month of follow-up, the percentage of biventricular pacing was greater than 95%.There were nineteen(66%) patients optimized LV pacing polar by the largest LVED and four (14%) patients by the DRLV. Of the 29 patients, 5(17%) patients used D1 as the pacing polar, 5(17%) patients used M2 as the pacing polar, 7(24%) patients used M3 as the pacing polar, and 12(41%) patients used P4 as the pacing polar. The pacing polars (D1, M2) of traditional bipolar lead were used in 10(34%) patients, and the LV quadripolar lead specific pacing polars (M3, P4) were used in 19(66%) patients.Compared to a LV quadripolar lead, the LV pacing polar (M3, P4) selected in 19(66%) patients were not achievable with the traditional LV bipolar lead (D1, M2). Preoperative QRS duration, LVESV, LVEF, LVEDD, 6MWD and NYHA class were (171±24)ms, (231±79)ml, (28±5)%, (74±11)mm, (294±103)m, (3.2±1.0)class and the postoperative 6-month were (130±12)ms, (158±73)ml, (36±10)%, (66±12)mm, (371±86)m, (1.9±0.5)class. These indexes were significantly improved after 6 months operation(P<0.001). 97% and 83% patients were responders of CRT as assessed by 6-month efficacy and echocardiographic efficacy. Conclusion: The maximal LVED and DRLV can be used to select LV pacing polar with a high rate of CRT response rate.

[Heart rate control in chronic heart failure patients received cardiovascular implantable electronic device therapy: effects of optimized medication].

Objective: To investigate the heart rate control situation of chronic heart failure (CHF) patients who received cardiovascular implantable electronic device (CIED) therapy, and to assess the heart rate control efficacy by optimized medication adjustment. Methods: We performed a perspective study in heart failure with reduced left ventricular ejection fraction (HFrEF) patients who received CIED according to guideline recommendations, patients were enrolled from January 2012 to January 2017. Resting heart rate (RHR) recorded by electrocardiogram after 10 minutes' rest and medication usage within 1 month were recorded at baseline. RHR less than 70 beats per minute (bpm) was regarded as well controlled. ß-receptor blockers and (or) ivabradine would be added in patients whose RHR were over 70 bpm. RHR after optimized medication adjustment was recorded during follow-up period. Results: One hundred and fifty patients were included in this study with average RHR (80.6±11.9) bpm. RHR was<70 bpm in 27.3% (41/150) patients at baseline and ß-receptor blockers was underused in 80.7% patients (88/109) whose RHR was>70 bpm. The overall RHR decreased to (73.1±10.4) bpm and percent of patients with RHR<70 bpm increased to 70.0% (105/150) after up-titration of ß-receptor blockers compared to baseline (χ2=52.958, P<0.001). Ivabradine was added in the rest 45 patients and RHR was<70 bpm in 43 out of 45 patients after ivabradine use. The overall RHR decreased to (67.1±2.7) bpm and percent of RHR<70 bpm significantly increased to 98.7% (148/150) (χ2=44.504, P<0.001 vs. up-titration of ß-receptor blockers only). Conclusion: RHR in CHF patients who received CIED therapy is not ideally controlled in this patient cohort, individual up-titration ofß-receptor blockers and ivabradine use may help to optimize RHR in these patients.

A novel surface modification scheme for ITO nanocrystals by acetylene: a combined experimental and DFT study.

Many applications of Sn-doped indium oxide (ITO) films in organic electronics require appropriate surface modifications of ITO nanocrystals with small organic molecules, such as silanes, phosophonic acids and carboxylic acids, to improve interfacial contacts and charge transfer. Here, we propose a new surface modification strategy via adsorption of acetylene molecules on an oxygen-terminated ITO(100) surface using a slab crystalline model to represent the nanocrystal surface. The adsorption was first studied using density functional theory. It was found that the chemisorption of C2H2 on two types of surface oxygen dimers is highly exothermic with the calculated adsorption energies of 3.80 eV and 5.19 eV, respectively. Electron population analysis reveals the origin of the strong interaction between the adsorbate and the ITO(100) surface. Experimental studies on the synthesized ITO nanocrystals using X-ray photoelectron spectroscopy and diffuse reflectance infrared Fourier transform spectroscopy confirm the predicted strong adsorption of C2H2 on ITO surfaces.

Amperometric nitric oxide sensor based on nanoporous platinum phthalocyanine modified electrodes.

This article describes the fabrication of electropolymerized Metallo 4', 4″, 4‴, 4'''' tetra-amine phthalocyanine (poly-MTAPc) modified electrodes for the detection of nitric oxide (NO) in phosphate-buffered saline (PBS) at pH 7.4. A two-step synthetic protocol using a laboratory microwave reactor was adopted to provide three MTAPc complexes bearing different metal centers (M = Cu(2+): CuTAPc, M = Zn(2+): ZnTAPc, and M = Pt(2+): PtTAPc). The MTAPc complexes and the intermediates were characterized by MALDI-TOF mass spectrometry, UV-vis spectroscopy, (1)H NMR spectroscopy, and elemental analysis. The MTAPc products were separately electropolymerized either onto a glassy carbon (GC) electrode as a thin-film or within the pores of Anodisc nanoporous alumina membrane as a densely packed array of poly-MTAPc nanotubes to produce two electrode systems. In the latter system, the surface area enhancement provided by the nanotube-arrayed morphology of the poly-MTAPc enabled a high faradaic (signal) to capacitative (background) current during NO electro-oxidation. Amperometric detection of NO using these two electrode systems shows that the sensitivity and linear ranges were insensitive to the metal centers (M = Cu(2+), Zn(2+), and Pt(2+)) of the poly-MTAPc material.

Healing of nanocracks by disclinations.

We present a new mechanism--discovered using molecular dynamics simulations--that leads to complete healing of nanocracks. This mechanism relies on the generation of crystal defects known as disclinations by migrating grain boundaries. Crack healing by disclinations does not require any compressive loads applied normal to the crack faces and even occurs under monotonic tensile loading. By closing small cracks and suppressing the propagation of others, this mechanism may provide a novel way of mitigating internal damage that influences ductility in nanocrystalline metals.

Gene expression profile in the liver tissue of geese after overfeeding.

Geese form a fatty liver after feeding on a carbohydrate-rich diet, possibly as an evolutionary adaptation to accumulate reserves for migration. To gain insight into the gene-regulation processes of hepatic steatosis in geese, we examined the profile of transcriptional expression in goose fatty liver and control liver by suppression subtractive hybridization and measured the levels of serum biochemical variables. We found 107 genes whose expression was different between the treatment and control groups. The main functions of these genes are metabolic processes, including the metabolism of carbohydrates, amino acids, and lipids. Twenty-four genes were classified using the Kyoto Encyclopaedia of Genes and Genomes pathways. Twelve genes that related to metabolic and cellular processes were confirmed by quantitative RT-PCR. A specific positive effect of feeding was observed on the expression of genes involved mainly in unsaturated fatty acids and triglyceride synthesis, and a negative effect was observed on genes involved in ß-oxidation, cholesterol metabolism, and glycolysis. The results could serve as an important reference for the development of goose breeding for fatty liver production and human liver disease research.

Propranolol inhibits the proliferation, migration and tube formation of hemangioma cells through HIF-1α dependent mechanisms.

The aim of this study was to investigate the mechanism of propranolol on the regression of hemangiomas. Propranolol-treated hemangioma tissues were collected and the expression of hypoxia inducible factor-1α (HIF-1α) was examined. We also established HIF-1α overexpression and knockdown hemangioma cells, and determined the effects of HIF-1α on the hemangioma cells proliferation, apoptosis, migration and tube formation. Significantly increased HIF-1α level was found in the hemangioma tissues compared to that in normal vascular tissues, whereas propranolol treatment decreased the HIF-1α level in hemangioma tissues in a time- and dose-dependent manner. Moreover, propranolol treatment significantly decreased cell proliferation, migration and tube formation as well as promoted cell apoptosis in HIF-1α overexpression and knockdown hemangioma cells. Propranolol suppressed the cells proliferation, migration and tube formation of hemangioma cells through HIF-1α dependent mechanisms. HIF-1α could serve as a novel target in the treatment of hemangiomas.

High-pitch spiral CT with 3D reformation: an alternative choice for imaging vascular anomalies with affluent blood flow in the head and neck of infants and children.

OBJECTIVE: To evaluate the feasibility of high-pitch spiral CT in imaging vascular anomalies (VAs) with affluent blood flow in the head and neck of infants and children. METHODS: For patients with suspected VAs and affluent blood flow pre-detected by ultrasound, CT was performed with high-pitch mode, individualized low-dose scan protocol and three-dimensional (3D) reformation. A five-point scale was used for image quality evaluation. Diagnostic accuracy was calculated with clinical diagnosis with/without pathological results as the reference standard. Radiation exposure and single-phase scan time were recorded. Treatment strategies were formulated based on CT images and results and were monitored through follow-up results. RESULTS: 20 lesions were identified in 15 patients (median age of 11 months). The mean score of image quality was 4.13 ± 0.74. 7 patients (7/15, 46.67%) were diagnosed with haemangiomas, 6 patients (6/15, 40%) were diagnosed with venous malformations and 2 patients (2/15, 13.33%) were diagnosed with arteriovenous malformations. The average effective radiation doses of a single phase and of the total procedure were 0.27 ± 0.08 and 0.86 ± 0.21 mSv. The average scanning time of a single phase was 0.46 ± 0.09 s. After treatment, 13 patients (13/15, 86.67%) achieved excellent results, and 2 patients (2/15, 13.33%) showed good results in follow-up visits. CONCLUSION: High-pitch spiral CT with an individualized low-dose scan protocol and 3D reformation is an effective modality for imaging VAs with affluent blood flow in the head and neck of infants and children when vascular details are needed and ultrasound and MRI could not provide the complete information. ADVANCES IN KNOWLEDGE: This study proposes an alternative modality for imaging VAs with affluent blood flow.

Preparative isolation and purification of lutein from the microalga chlorella vulgaris by high-speed counter-current chromatography.

High-speed counter-current chromatography (HSCCC) was applied to the isolation and purification of lutein from microalgae. Analytical HSCCC was used for the preliminary selection of a suitable solvent system composed of n-hexane-ethanol-water (4:3:1, v/v). Using the above solvent system, preparative HSCCC was successfully performed yielding lutein at 98% purity from 200 mg of the crude extract in a one-step separation.

Characterization and third-order optical nonlinearities of uniform surface-modified CdS nanoparticles.

Size-controlled uniform surface-capped CdS nanoparticles were readily prepared by an improved inverse microemulsion technique using hexanethiol as co-surfactant. The third-order optical nonlinearities were studied for the first time by newly-developed Z-scan technique, from which the enhanced nonlinear optical responses were observed after heat-treatment.

[Study on prolonged action cefotoxime].

A prolonged action cephalosporin was prepared by the reaction of cefotaxime sodium (CTX) with N,N-dibenzylethylene diamine acetate. It is reasonable to consider the resultant as benzathine cefotaxime (BCTX) by means of elemental analysis, DSC, UV spectra, IR spectra, NMR spectra and mass spectra. In contrast to CTX, BCTX appeared to be almost insoluble in water and its intrinsic dissolution rate was 0.183 micrograms/ml.min. The stability revealed that the degradation of BCTX suspension in water followed zero-order kinetics and the rate of degradation at room temperature was found to be 1.67 X 10(-7) mg/ml.s. An in vivo test by using 12 rabbits given BCTX suspension and CTX solution intramuscularly was conducted. The results showed that the former was longer in maintaining serum drug level than the latter.

Rooting depth and leaf hydraulic conductance in the xeric tree Haloxyolon ammodendron growing at sites of contrasting soil texture.

An experiment was conducted on Haloxylon ammodendron C.A. Mey, a small xeric tree. Soil water content, soil evaporation, leaf water potential, leaf transpiration rate and stomatal conductance were measured at the two sites that contrast in soil texture: sandy and heavy textured, 8 km apart on the southern periphery of Gurbantonggut Desert, Central Asia, during the 2005 and 2006 growing seasons. Leaf specific hydraulic conductance was calculated from the measurements, and root distributions of plants grown at the two sites were quantified by whole-root system excavation. In general, plants grown in sandy soil experienced better water status than in heavy textured soil. Low soil evaporation loss is not the main reason for this better plant water status at sandy site. Plants in sandy soil developed much deeper root systems, larger root surface areas and higher root: leaf surface area ratio than in heavy textured soil, which facilitated plants acquiring more water and surviving the prolonged drought period. Plants growing at light textured sites should have an advantage in acclimatising to the changed water conditions of the future. Plants at the more sandy sites have a larger buffering capacity to excessive variation in ambient conditions.

Molecular anchor Cu-S formed on a thiophene mediated Si(111)-(7x7) surface.

Thiophene molecule selectively binds to the adjacent adatom-rest atom pair on the Si(111)-(7x7) surface through its alpha-carbon atoms, leading to the covalent attachment of a C-S-C linkage and remaining C=C (beta-carbon) bond onto the surface. Photoemission studies show that Cu atom readily adsorbs onto the S atom of the functional group to form the Cu-S molecular anchor in two forms: one points away from the thiophene C=C group; the other points toward the C=C group.

Synthesis of a troponin C cDNA and expression of wild-type and mutant proteins in Escherichia coli.

An avian fast striated muscle troponin C cDNA was designed and synthesized from six oligonucleotides using the overlap-fill in method and overproduced in Escherichia coli for the purpose of developing recombinant DNA approaches to study structure-function relationships in this calcium-binding regulatory protein. The recombinant protein isolated from E. coli functions as a bona fide troponin C in all properties that were assayed: calcium binding, calcium-dependent conformational change, calcium-dependent interaction with troponin I, and formation of a functional ternary complex with troponin I and troponin T that can confer calcium sensitivity on the actomyosin MgATPase. The initiating methionine was removed by E. coli leaving alanine as the first amino acid, as in the muscle troponin C. The first amino acid was not acetylated, but this difference from the muscle protein has no apparent effect on the function. The presence of Glu at position 99, as in turkey, versus Ala in chicken resulted in no detectable difference in comparing recombinant with chicken troponin C. A mutant in which residues 91-93 (Lys-Gly-Lys) in the D/E helical linker were deleted differs in function from wild-type troponin C in the conformational change that takes place upon calcium binding and its interaction with troponin I. Also, the mutant troponin C is impaired in its ability to form a functional complex with troponin I and troponin T that will confer calcium sensitivity on the actomyosin MgATPase.

The cooperative behavior of yeast D-glyceraldehyde-3-phosphate. Dehydrogenase as studied by the formation of the fluorescent NAD derivative.

The ultraviolet irradiation of the yeast D-glyceraldehyde-3-phosphate dehydrogenase carboxymethylated at the active site Cys residues, as with the rabbit muscle enzyme, led to the formation of a fluorescent NAD derivative with an emission maximum at 410 nm. Similar results were obtained with the enzyme selectively carboxymethylated at only 2 of its 4 active site Cys residues. The binding of NAD+ to both the carboxymethylated enzymes is non-cooperative or only weakly negatively cooperative when determined by NAD+ quenching of the intrinsic protein fluorescence. However, determinations of the amount of fluorescent NAD derivative formed under different NAD+ concentrations show that both the carboxymethylated enzymes appeared to bind NAD+ with positive cooperativity as in the case of the binding of NAD+ to the native apoenzyme. This seems to suggest that the spatial positioning of the nicotinamide moiety at the active site of the irradiated enzyme resembles more closely that of the nicotinamide ring in the native holoenzyme as compared to the carboxymethylated enzymes.

Modified calcium-dependent regulatory function of troponin C central helix mutants.

Mutations have been made in the exposed region of the avian troponin C central helix, the D/E linker, which change its length and the orientation of the Ca2(+)-binding domains relative to each other. The region 87Glu-Asp-Ala-Lys-Gly-Lys-Ser-Glu-Glu-Glu97 has been altered in five deletion (d) mutants: dEDA, dKG, dKGK, dSEEE, and dKEDAKGK. The recombinant troponin Cs were expressed in Escherichia coli, purified, and assayed for function. All mutants retained basic troponin C function. They all bound Ca2+ to the low and high affinity sites, and they all were able to confer Ca2+ sensitivity on the regulated actomyosin ATPase. However, the regulatory function of all mutants except dSEEE was defective in one part of the Ca2+ switch or the other. In certain conditions dKGK and dKEDAKGK failed to inhibit fully whereas dEDA and dKG failed to activate the regulated actomyosin ATPase fully. The following general conclusions have been made. (a) The length of the D/E linker per se (assuming the linker is helical) and the orientation of the two Ca2(+)-binding domains relative to each other are not crucial for regulation. (b) The conserved charge cluster 95Glu-Glu-Glu97, in a region of troponin C known to bind to troponin I and postulated to be required for regulation, appears to be unimportant for function. (c) Deletion of 88Glu-Asp-Ala90 resulted in a troponin C that could not activate the actomyosin (or S1) ATPase over the level of actomyosin alone, thus defining a role for troponin C in this aspect of thin filament regulation. The results have been interpreted in terms of the crystallographic structure of troponin C and related to results with analogous calmodulin mutants.