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Immunological characterization of rice tungro spherical virus coat proteins and differentiation of isolates from the Philippines and India

Druka A, Burns T, Zhang S, Hull R

J Gen Virol, 1996 Aug;77 ( Pt 8):1975-83.
PMID: 8760450

Rice tungro spherical virus (RTSV) has an RNA genome of more than 12 kb with various features which classify it as a plant picornavirus. The capsid comprises three coat protein (CP) species, CP1, CP2 and CP3, with predicted molecular masses of 22.5, 22.0 and 33 kDa, respectively, which are cleaved from a polyprotein. In order to obtain information on the properties of these proteins, each was expressed in E. coli, purified as a fusion to the maltose-binding protein and used for raising a polyclonal antiserum. CP1, CP2 and CP3 with the expected molecular masses were detected specifically in virus preparations. CP3 is probably the major antigenic determinant on the surface of RTSV particles, as was shown by ELISA, Western blotting and immunogold electron microscopy using antisera obtained against whole virus particles and to each CP separately. In some cases, especially in crude extracts, CP3 antiserum detected several other proteins (40-42 kDa), which could be products of CP3 post-translational modification. No serological differences were detected between the three CPs from isolates from the Philippines, Thailand, Malaysia and India. The CP3-related 40-42 kDa proteins of the Indian RTSV isolate have a slightly higher electrophoretic mobility (42-44 kDa) and a different response to cellulolytic enzyme preparations, which allows them to be differentiated from south-east Asian isolates.
Variation in coat protein genes among five geographically different isolates of rice tungro spherical virus

Zhang S, Lee G, Davies JW, Hull R

Arch Virol, 1997;142(9):1873-9.
PMID: 9672645

The variation in the sequence of the coat protein genes of four isolates of rice tungro spherical virus from different countries, Malaysia, Thailand, India and Bangladesh, was compared with an isolate from the Philippines. The evidence from RT-PCR, Southern blot hybridization and sequences of the coat protein genes indicated that the isolates appeared to fall into two groups. One comprised the Philippine and Malaysian isolates (about 95% sequence similarity) and the other the Bangladeshi and Indian isolates, the sequences of which differed by about 15% from that of the Philippine isolate. The Thai isolate seemed to be a mixture of these two subgroups.
Sequences of the three coat protein genes of a Malaysian isolate of rice tungro spherical virus reveal a close relationship to the Philippine isolate

Zhang S, Davies JW, Hull R

Virus Genes, 1997;15(1):61-4.
PMID: 9354271

Coat protein genes CP1, CP2 and CP3 of an isolate (MaP1) of rice tungro spherical virus (RTSV) from Malaysia were isolated, cloned and sequenced. Comparative analysis indicated that MaP1 isolate is closely related to the Philippine isolate.
The concentration of selected minerals and phytate in Malaysian Brachiaria decumbens

Noordin MM, Zhang SS, Rahman SO, Haron J

Vet Hum Toxicol, 2000 Oct;42(5):276-9.
PMID: 11003117

Samples of Brachiaria decumbens collected from 5 farms representing the Peninsular Malaysia were subjected to selected trace mineral and phytate analyses to explain the pathogenesis of B decumbens intoxication. Concentrations of Cu, Zn, Fe and Mo were comparable to other grasses while that of phytate was low. The molar ratios of Cu:Zn, Cu:Mo, and Cu:Fe warrant that Cu deficiency is involved in the toxicity of B decumbens. This might aggravate the development of photosensitization of unpigmented or lightly pigmented areas of affected animals. The Zn:phytate ratio could predispose to Zn deficiency during intoxication.
Effects of copper overload on hepatic lipid peroxidation and antioxidant defense in rats

Zhang SS, Noordin MM, Rahman SO, Haron J

Vet Hum Toxicol, 2000 Oct;42(5):261-4.
PMID: 11003114

The influence of copper (Cu) overload on hepatic lipid peroxidation and antioxidation defense capacity was studied by overloading rats with copper sulphate orally (500 mg Cu/kg bw) 5 d/w for 8 w. Malondialdehyde (MDA), Cu-Zn superoxide dismutase (SOD), and Se-glutathione peroxidase (GSH-Px) were measured in serum and liver homogenate at 2, 4 and 8 w of dosing. Liver Cu concentration and alanine aminotransferase (ALT) activity were also determined. As Cu loading progressed, there were multiparameter changes with significant ALT elevation, increased MDA concentrations in serum and liver homogenate, and dramatic declines of SOD and GSH-Px activities in erythrocytes and whole blood respectively, along with marked elevation of hepatic Cu in the Cu-dosed group. Excessive Cu accumulation in the liver depressed SOD and GSH-Px activities and resulted in high MDA in serum and liver homogenate due to the lipid peroxidation induced by the Cu overload.
The effect of zinc supplementation on antioxidant and lipid peroxidation status during Brachiaria decumbens intoxication in sheep

Zhang SS, Noordin MM, Rahman SO, Haron MJ

Vet Hum Toxicol, 2001 Apr;43(2):83-7.
PMID: 11308125

An attempt was made to clarify the association between zinc (Zn) and antioxidants due to Zn supplementation on lipid peroxidation occurring during Brachiaria decumbens intoxication. The concentration of Zn, copper, malondialdehyde (MDA), superoxide dismutase (SOD), and gluthathione peroxidase (GSH-Px) were determined in tissues. There was a gradual increment in the concentration of Zn and MDA in serum and hepatocytic SOD in groups given Zn + B decumbens. A decline in erythrocytic GSH-Px and SOD, and lower concentration of reduced glutathione in hepatocyte cytosols were also detected in these sheep. It is highly suggestive that Zn supplementation may depress antioxidant status and enhance lipid peroxidation during B decumbens intoxication.
Genetic diversity and molecular identification of mosquito species in the Anopheles maculatus group using the ITS2 region of rDNA

Walton C, Somboon P, O'Loughlin SM, Zhang S, Harbach RE, Linton YM, et al.

Infect Genet Evol, 2007 Jan;7(1):93-102.
PMID: 16782411

The species diversity and genetic structure of mosquitoes belonging to the Anopheles maculatus group in Southeast Asia were investigated using the internal transcribed spacer 2 (ITS2) of ribosomal DNA (rDNA). A molecular phylogeny indicates the presence of at least one hitherto unrecognised species. Mosquitoes of chromosomal form K from eastern Thailand have a unique ITS2 sequence that is 3.7% divergent from the next most closely related taxon (An. sawadwongporni) in the group. In the context of negligible intraspecific variation at ITS2, this suggests that chromosomal form K is most probably a distinct species. Although An. maculatus sensu stricto from northern Thailand and southern Thailand/peninsular Malaysia differ from each other in chromosomal banding pattern and vectorial capacity, no intraspecific variation was observed in the ITS2 sequences of this species over this entire geographic area despite an extensive survey. A PCR-based identification method was developed to distinguish five species of the group (An. maculatus, An. dravidicus, An. pseudowillmori, An. sawadwongporni and chromosomal form K) to assist field-based studies in northwestern Thailand. Sequences from 187 mosquitoes (mostly An. maculatus and An. sawadwongporni) revealed no intraspecific variation in specimens from Thailand, Cambodia, mainland China, Malaysia, Taiwan and Vietnam, suggesting that this identification method will be widely applicable in Southeast Asia. The lack of detectable genetic structure also suggests that populations of these species are either connected by gene flow and/or share a recent common history.
Reducing risk through real options in systems design: the case of architecting a maritime domain protection system

Buurman J, Zhang S, Babovic V

Risk Anal, 2009 Mar;29(3):366-79.
PMID: 19076327 DOI: 10.1111/j.1539-6924.2008.01160.x

Complex engineering systems are usually designed to last for many years. Such systems will face many uncertainties in the future. Hence the design and deployment of these systems should not be based on a single scenario, but should incorporate flexibility. Flexibility can be incorporated in system architectures in the form of options that can be exercised in the future when new information is available. Incorporating flexibility comes, however, at a cost. To evaluate if this cost is worth the investment a real options analysis can be carried out. This approach is demonstrated through analysis of a case study of a previously developed static system-of-systems for maritime domain protection in the Straits of Malacca. This article presents a framework for dynamic strategic planning of engineering systems using real options analysis and demonstrates that flexibility adds considerable value over a static design. In addition to this it is shown that Monte Carlo analysis and genetic algorithms can be successfully combined to find solutions in a case with a very large number of possible futures and system designs.
First Report of Damping-Off on Basella rubra Caused by Rhizoctonia solani Anastomosis Group 4 in Florida

Liao X, Fu Y, Zhang S, Duan YP

Plant Dis, 2012 Feb;96(2):288.
PMID: 30731824 DOI: 10.1094/PDIS-08-11-0639

Indian spinach (Basella rubra L.) is a red stem species of Basella that is cultivated worldwide as an ornamental and the aerial parts are also consumed as a vegetable. In May of 2011, symptoms of damping-off were observed on approximately 10% of the plants at the stem base around the soil line of seedlings in a greenhouse in Homestead, FL. Lesions were initially water soaked, grayish to dark brown, irregular in shape, and sunken in appearance on large plants, causing the infected seedlings to collapse and eventually die. Symptomatic stem tissue was surface sterilized with 0.6% sodium hypochlorite, rinsed in sterile distilled water, air dried, and plated on potato dextrose agar (PDA). Plates were incubated at 25°C in darkness for 3 to 5 days. A fungus was isolated in all six isolations from symptomatic tissues on PDA. Fungal colonies on PDA were light gray to brown with abundant growth of mycelia, and the hyphae tended to branch at right angles when examined under a microscope. A septum was always present in the branch of hyphae near the originating point and a slight constriction at the branch was observed. Neither conidia nor conidiophores were found from the cultures on PDA. The characteristics of hyphae, especially the right angle branching of mycelia, indicate close similarity to those of Rhizoctonia solani (2,3). The internal transcribed spacer (ITS) region of rDNA was amplified with the primers ITS1/ITS4 and sequenced (GenBank Accession No. JN545836). Subsequent database searches by the BLASTN program indicated that the resulting sequence had a 100% identity over 472 bp with the corresponding gene sequence of R. solani anastomosis group (AG) 4 (GenBank Accession No. JF701752.1), a fungal pathogen reported to cause damping-off on many crops. Pathogenicity was confirmed through inoculation of healthy India spinach plants with the hyphae of isolates. Four 4-week-old plants were inoculated with the isolates by placing a 5-mm PDA plug of mycelia at the stem base and covering with a thin layer of the soil. Another four plants treated with sterile PDA served as a control. After inoculation, the plants were covered with plastic bags for 24 h and maintained in a greenhouse with ambient conditions. Four days after inoculation, water-soaked, brown lesions, identical to the symptoms described above, were observed on the stem base of all inoculated plants, whereas no symptoms developed on the control plants. The fungus was isolated from affected stem samples, and the identity was confirmed by microscopic appearance of the hyphae and sequencing the ITS1/ITS4 intergenic spacer region, fulfilling Koch's postulates. This pathogenicity test was conducted twice. R. solani has been reported to cause damping-off of B. rubra in Ghana (1) and Malaysia (4). To our knowledge, this is the first report of damping-off caused by R. solani AG-4 on Indian spinach in Florida and the United States. With the increased interest in producing Asian vegetables for food and ornamental purposes, the occurrence of damping-off on Indian spinach needs to be taken into account when designing programs for disease management in Florida. References: (1) H. A. Dade. XXIX. Bull. Misc. Inform. 6:205, 1940. (2) J. R. Parmeter et al. Phytopathology 57:218, 1967. (3) B. Sneh et al. Identification of Rhizoctonia species. The American Phytopathological Society, St Paul, MN, 1991. (4) T. H. Williams and P. S. W. Liu. Phytopathol. Pap. 19:1, 1976.
Proteomic profile of edible bird's nest proteins

Liu X, Lai X, Zhang S, Huang X, Lan Q, Li Y, et al.

J Agric Food Chem, 2012 Dec 26;60(51):12477-81.
PMID: 23214475 DOI: 10.1021/jf303533p

Edible bird's nest (EBN) is made of the swiftlets' saliva, which has attracted rather more attention owing to its nutritious and medical properties. Although protein constitutes the main composition and plays an important role in EBN, few studies have focused on the proteomic profile of EBN. The purpose of this study was to produce a proteomic map and clarify common EBN proteins. Liquid-phase isoelectric focusing (LIEF) was combined with two-dimensional electrophoresis (2-DE) for comprehensive analysis of EBN proteins. From 20 to 100 protein spots were detected on 2-DE maps of EBN samples from 15 different sources. The proteins were mainly distributed in four taxa (A, B, C, and D) according to their molecular mass. Taxa A and D both contained common proteins and proteins that may be considered another characteristic of EBN. Taxon A was identified using MALDI-TOF-TOF/MS and found to be homologous to acidic mammalian chitinase-like ( Meleagris gallopavo ), which is in glycosyl hydrolase family 18.
Fulltext The impact of SLCO1B1 genetic polymorphisms on neonatal hyperbilirubinemia: a systematic review with meta-analysis

Liu J, Long J, Zhang S, Fang X, Luo Y

J Pediatr (Rio J), 2013 07 11;89(5):434-43.
PMID: 23850112 DOI: 10.1016/j.jped.2013.01.008

OBJECTIVE: To determine whether three variants (388 G>A, 521 T>C, and 463 C>A) of the solute carrier organic anion transporter family member 1B1 (SLCO1B1) are associated with neonatal hyperbilirubinemia.
DATA SOURCE: The China National Knowledge Infrastructure and MEDLINE databases were searched. The systematic review with meta-analysis included genetic studies which assessed the association between neonatal hyperbilirubinemia and 388 G>A, 521 T>C, and 463 C>A variants of SLCO1B1 between January of 1980 and December of 2012. Data selection and extraction were performed independently by two reviewers.
SUMMARY OF THE FINDINGS: Ten articles were included in the study. The results revealed that SLCO1B1 388 G>A is associated with an increased risk of neonatal hyperbilirubinemia (OR, 1.39; 95% CI, 1.07-1.82) in Chinese neonates, but not in white, Thai, Latin American, or Malaysian neonates. The SLCO1B1 521 T>C mutation showed a low risk of neonatal hyperbilirubinemia in Chinese neonates, while no significant associations were found in Brazilian, white, Asian, Thai, and Malaysian neonates. There were no significant differences in SLCO1B1 463 C>A between the hyperbilirubinemia and the control group.
CONCLUSION: This study demonstrated that the 388 G>A mutation of the SLCO1B1 gene is a risk factor for developing neonatal hyperbilirubinemia in Chinese neonates, but not in white, Thai, Brazilian, or Malaysian populations; the SLCO1B1 521 T>C mutation provides protection for neonatal hyperbilirubinemia in Chinese neonates, but not in white, Thai, Brazilian, or Malaysian populations.
Fulltext Asian Sudden Cardiac Death in Heart Failure (ASIAN-HF) registry

Lam CS, Anand I, Zhang S, Shimizu W, Narasimhan C, Park SW, et al.

Eur J Heart Fail, 2013 Aug;15(8):928-36.
PMID: 23568645 DOI: 10.1093/eurjhf/hft045

Our aim is to determine mortality and morbidity in Asian patients under clinical management for heart failure (HF). Specifically, we will define the incidence of, and risk factors for, sudden cardiac death, as well as the socio-cultural factors influencing therapeutic choices in these patients. Methods This is a prospective observational multinational Asian registry of 5000 patients with symptomatic HF (stage C) and LV systolic dysfunction (EF ≤ 40%) involving 44 centres across 11 Asian regions (China, Hong Kong, India, Indonesia, Japan, Korea, Malaysia, Philippines, Singapore, Taiwan and Thailand). Data collection includes demographic variables, clinical symptoms, functional status, date of HF diagnosis and prior cardiovascular investigations, clinical risk factors, lifestyle factors, socio-economic status, and survey of cultural beliefs, health practices, and attitudes towards device therapy. Centre-level characteristics (case load, referral pattern, specialization, and infrastructure) are also obtained. Patients uniformly undergo standard 12-lead ECG and transthoracic echocardiography at baseline, and are followed over 3 years for outcomes of death or hospitalization. The mode of death and cause of hospitalization are adjudicated by a central event adjudication committee using pre-specified criteria. Perspective By providing prospective data regarding the demographics, risk factors, and outcomes of Asian patients under treatment for HF, the ASIAN-HF registry is expected to advance fundamental understanding of the burden and predictors of death and hospitalization among these patients. The knowledge gained will be important for guiding resource allocation and planning preventive strategies to address the unmet and growing clinical needs of patients with cardiovascular disease in Asia. Trial registration NCT01633398.
[Genetic variation of the hemagglutinin and neuraminidase of influenza B viruses isolated in Ningbo during 2010-2012]

Hu FJ, Li YD, Jiao SL, Zhang S

Zhonghua Yu Fang Yi Xue Za Zhi, 2013 Dec;47(12):1100-4.
PMID: 24529267

To investigate the epidemiological characteristics of influenza B viruses and explore the genetic evolution characteristics of the hemagglutinin(HA) and neuraminidase(NA) genes of local isolated strains in Ningbo, Southeast China, during 2010 to 2012.
Fulltext Molecular epidemiology of coxsackievirus A16: intratype and prevalent intertype recombination identified

Chen X, Tan X, Li J, Jin Y, Gong L, Hong M, et al.

PLoS One, 2013;8(12):e82861.
PMID: 24340064 DOI: 10.1371/journal.pone.0082861

Coxsackievirus A16 (CVA16) is responsible for nearly 50% of all the conﬁrmed hand, foot, and mouth disease (HFMD) cases in mainland China, sometimes it could also cause severe complications, and even death. To clarify the genetic characteristics and the epidemic patterns of CVA16 in mainland China, comprehensive bioinfomatics analyses were performed by using 35 CVA16 whole genome sequences from 1998 to 2011, 593 complete CVA16 VP1 sequences from 1981 to 2011, and prototype strains of human enterovirus species A (EV-A). Analysis on complete VP1 sequences revealed that subgenotypes B1a and B1b were prevalent strains and have been co-circulating in many Asian countries since 2000, especially in mainland China for at least 13 years. While the prevalence of subgenotype B1c (totally 20 strains) was much limited, only found in Malaysia from 2005 to 2007 and in France in 2010. Genotype B2 only caused epidemic in Japan and Malaysia from 1981 to 2000. Both subgenotypes B1a and B1b were potential recombinant viruses containing sequences from other EV-A donors in the 5'-untranslated region and P2, P3 non-structural protein encoding regions.
Fulltext 5' isomiR variation is of functional and evolutionary importance

Tan GC, Chan E, Molnar A, Sarkar R, Alexieva D, Isa IM, et al.

Nucleic Acids Res, 2014 Aug;42(14):9424-35.
PMID: 25056318 DOI: 10.1093/nar/gku656

We have sequenced miRNA libraries from human embryonic, neural and foetal mesenchymal stem cells. We report that the majority of miRNA genes encode mature isomers that vary in size by one or more bases at the 3' and/or 5' end of the miRNA. Northern blotting for individual miRNAs showed that the proportions of isomiRs expressed by a single miRNA gene often differ between cell and tissue types. IsomiRs were readily co-immunoprecipitated with Argonaute proteins in vivo and were active in luciferase assays, indicating that they are functional. Bioinformatics analysis predicts substantial differences in targeting between miRNAs with minor 5' differences and in support of this we report that a 5' isomiR-9-1 gained the ability to inhibit the expression of DNMT3B and NCAM2 but lost the ability to inhibit CDH1 in vitro. This result was confirmed by the use of isomiR-specific sponges. Our analysis of the miRGator database indicates that a small percentage of human miRNA genes express isomiRs as the dominant transcript in certain cell types and analysis of miRBase shows that 5' isomiRs have replaced canonical miRNAs many times during evolution. This strongly indicates that isomiRs are of functional importance and have contributed to the evolution of miRNA genes.
Fulltext Cardiovascular risk and events in 17 low-, middle-, and high-income countries

Yusuf S, Rangarajan S, Teo K, Islam S, Li W, Liu L, et al.

N Engl J Med, 2014 08 28;371(9):818-27.
PMID: 25162888 DOI: 10.1056/NEJMoa1311890

BACKGROUND: More than 80% of deaths from cardiovascular disease are estimated to occur in low-income and middle-income countries, but the reasons are unknown.
METHODS: We enrolled 156,424 persons from 628 urban and rural communities in 17 countries (3 high-income, 10 middle-income, and 4 low-income countries) and assessed their cardiovascular risk using the INTERHEART Risk Score, a validated score for quantifying risk-factor burden without the use of laboratory testing (with higher scores indicating greater risk-factor burden). Participants were followed for incident cardiovascular disease and death for a mean of 4.1 years.
RESULTS: The mean INTERHEART Risk Score was highest in high-income countries, intermediate in middle-income countries, and lowest in low-income countries (P<0.001). However, the rates of major cardiovascular events (death from cardiovascular causes, myocardial infarction, stroke, or heart failure) were lower in high-income countries than in middle- and low-income countries (3.99 events per 1000 person-years vs. 5.38 and 6.43 events per 1000 person-years, respectively; P<0.001). Case fatality rates were also lowest in high-income countries (6.5%, 15.9%, and 17.3% in high-, middle-, and low-income countries, respectively; P=0.01). Urban communities had a higher risk-factor burden than rural communities but lower rates of cardiovascular events (4.83 vs. 6.25 events per 1000 person-years, P<0.001) and case fatality rates (13.52% vs. 17.25%, P<0.001). The use of preventive medications and revascularization procedures was significantly more common in high-income countries than in middle- or low-income countries (P<0.001).
CONCLUSIONS: Although the risk-factor burden was lowest in low-income countries, the rates of major cardiovascular disease and death were substantially higher in low-income countries than in high-income countries. The high burden of risk factors in high-income countries may have been mitigated by better control of risk factors and more frequent use of proven pharmacologic therapies and revascularization. (Funded by the Population Health Research Institute and others.).
Note: Malaysia is a study site (Author: Yusoff K)
Fulltext The rationale and design of the Micra Transcatheter Pacing Study: safety and efficacy of a novel miniaturized pacemaker

Ritter P, Duray GZ, Zhang S, Narasimhan C, Soejima K, Omar R, et al.

Europace, 2015 May;17(5):807-13.
PMID: 25855677 DOI: 10.1093/europace/euv026

Recent advances in miniaturization technologies and battery chemistries have made it possible to develop a pacemaker small enough to implant within the heart while still aiming to provide similar battery longevity to conventional pacemakers. The Micra Transcatheter Pacing System is a miniaturized single-chamber pacemaker system that is delivered via catheter through the femoral vein. The pacemaker is implanted directly inside the right ventricle of the heart, eliminating the need for a device pocket and insertion of a pacing lead, thereby potentially avoiding some of the complications associated with traditional pacing systems.
Fulltext Early performance of a miniaturized leadless cardiac pacemaker: the Micra Transcatheter Pacing Study

Ritter P, Duray GZ, Steinwender C, Soejima K, Omar R, Mont L, et al.

Eur Heart J, 2015 Oct 1;36(37):2510-9.
PMID: 26045305 DOI: 10.1093/eurheartj/ehv214

Permanent cardiac pacing is the only effective treatment for symptomatic bradycardia, but complications associated with conventional transvenous pacing systems are commonly related to the pacing lead and pocket. We describe the early performance of a novel self-contained miniaturized pacemaker.
Fulltext Improve the prevention of sudden cardiac arrest in emerging countries: the Improve SCA clinical study design

Zhang S, Singh B, Rodriguez DA, Chasnoits AR, Hussin A, Ching CK, et al.

Europace, 2015 Nov;17(11):1720-6.
PMID: 26037794 DOI: 10.1093/europace/euv103

This study aims to demonstrate that primary prevention (PP) patients with one or more additional risk factors are at a similar risk of life-threatening ventricular arrhythmias when compared with secondary prevention (SP) patients, and would receive similar benefit from an implantable cardioverter defibrillator (ICD), or cardiac resynchronization therapy-defibrillator (CRT-D) implant. The study evaluates the benefits of therapy for high-risk patients in countries where defibrillation therapy for PP of SCA is underutilized.
Fulltext A leadless intracardiac transcatheter pacing system

Reynolds D, Duray GZ, Omar R, Soejima K, Neuzil P, Zhang S, et al.

N Engl J Med, 2016 Feb 11;374(6):533-41.
PMID: 26551877 DOI: 10.1056/NEJMoa1511643

BACKGROUND: A leadless intracardiac transcatheter pacing system has been designed to avoid the need for a pacemaker pocket and transvenous lead.
METHODS: In a prospective multicenter study without controls, a transcatheter pacemaker was implanted in patients who had guideline-based indications for ventricular pacing. The analysis of the primary end points began when 300 patients reached 6 months of follow-up. The primary safety end point was freedom from system-related or procedure-related major complications. The primary efficacy end point was the percentage of patients with low and stable pacing capture thresholds at 6 months (≤2.0 V at a pulse width of 0.24 msec and an increase of ≤1.5 V from the time of implantation). The safety and efficacy end points were evaluated against performance goals (based on historical data) of 83% and 80%, respectively. We also performed a post hoc analysis in which the rates of major complications were compared with those in a control cohort of 2667 patients with transvenous pacemakers from six previously published studies.
RESULTS: The device was successfully implanted in 719 of 725 patients (99.2%). The Kaplan-Meier estimate of the rate of the primary safety end point was 96.0% (95% confidence interval [CI], 93.9 to 97.3; P<0.001 for the comparison with the safety performance goal of 83%); there were 28 major complications in 25 of 725 patients, and no dislodgements. The rate of the primary efficacy end point was 98.3% (95% CI, 96.1 to 99.5; P<0.001 for the comparison with the efficacy performance goal of 80%) among 292 of 297 patients with paired 6-month data. Although there were 28 major complications in 25 patients, patients with transcatheter pacemakers had significantly fewer major complications than did the control patients (hazard ratio, 0.49; 95% CI, 0.33 to 0.75; P=0.001).
CONCLUSIONS: In this historical comparison study, the transcatheter pacemaker met the prespecified safety and efficacy goals; it had a safety profile similar to that of a transvenous system while providing low and stable pacing thresholds. (Funded by Medtronic; Micra Transcatheter Pacing Study ClinicalTrials.gov number, NCT02004873.).

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