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PubMed1998

Molecular characterization of the SUMO-1 modification of RanGAP1 and its role in nuclear envelope association.

The mammalian guanosine triphosphate (GTP)ase-activating protein RanGAP1 is the first example of a protein covalently linked to the ubiquitin-related protein SUMO-1. Here we used peptide mapping, mass spectroscopy analysis, and mutagenesis to identify the nature of the link between RanGAP1 and SUMO-1. SUMO-1 is linked to RanGAP1 via glycine 97, indicating that the last 4 amino acids of this 101- amino acid protein are proteolytically removed before its attachment to RanGAP1. Recombinant SUMO-1 lacking the last four amino acids is efficiently used for modification of RanGAP1 in vitro and of multiple unknown proteins in vivo. In contrast to most ubiquitinated proteins, only a single lysine residue (K526) in RanGAP1 can serve as the acceptor site for modification by SUMO-1. Modification of RanGAP1 with SUMO-1 leads to association of RanGAP1 with the nuclear envelope (NE), where it was previously shown to be required for nuclear protein import. Sufficient information for modification and targeting resides in a 25-kD domain of RanGAP1. RanGAP1-SUMO-1 remains stably associated with the NE during many cycles of in vitro import. This indicates that removal of RanGAP1 from the NE is not a required element of nuclear protein import and suggests that the reversible modification of RanGAP1 may have a regulatory role.

Amino Acid Sequence↗

PubMed1999

Modification of cysteine residues in vitro and in vivo affects the immunogenicity and antigenicity of major histocompatibility complex class I-restricted viral determinants.

In studying the subdominant status of two cysteine-containing influenza virus nuclear protein (NP) determinants (NP39-47 and NP218-226) restricted by H-2Kd, we found that the antigenicity of synthetic peptides was enhanced 10-100-fold by treatment with reducing agents, despite the fact that the affinity for Kd was not enhanced. Reducing agents also markedly enhanced the immunogenicity of cysteine-containing peptides, as measured by propagation of long-term T cell lines in vitro. Similar enhancing effects were obtained by substituting cysteine with alanine or serine in the synthetic peptides, demonstrating that sulfhydryl modification of cysteine is responsible for the impaired antigenicity and immunogenicity of NP39-47 and NP218-226. We found similar effects for two widely studied, cysteine-containing peptides from lymphocytic choriomeningitis virus. The major modifications of cysteine-containing synthetic peptides are cysteinylation and dimerization occurring through cysteine residues. We demonstrate that both of these modifications occur in cells synthesizing a cytosolic NP218-226 minigene product and, further, that T cells specific for cysteinylated NP218-226 are induced by influenza virus infection in mice, demonstrating that this modification occurs in vivo. These findings demonstrate that posttranslational modifications affect the immunogenicity and antigenicity of cysteine-containing viral peptides and that this must be considered in studying the status of such peptides in immunodominance hierarchies.

Amino Acid Sequence↗

PubMed1988

Modification of a carboxyl group that appears to cross the permeability barrier in the red blood cell anion transporter.

A recently developed method for converting protein carboxyl groups to alcohols has been used to examine the functional role of carboxyl groups in the red blood cell inorganic anion-transport protein (band 3). A major goal of the work was to investigate the carboxyl group that is protonated during the proton-sulfate cotransport that takes place during net chloride-sulfate exchange. Three kinds of evidence indicate that the chemical modification (Woodward's reagent K followed by borohydride) converts this carboxyl to an alcohol. First, monovalent anion exchange is inhibited irreversibly. Second, the modification stimulates sulfate influx into chloride-loaded cells and nearly eliminates the extracellular pH dependence of the sulfate influx. (The stimulated sulfate influx in the modified cells is inhibitable by stilbenedisulfonate.) Third, the proton influx normally associated with chloride-sulfate exchange is inhibited by the modification. These results would all be expected if the titratable carboxyl group were converted into the untitratable, neutral alcohol. In addition to altering the extracellular pH dependence of sulfate influx, the chemical modification removes the intracellular pH dependence of sulfate efflux. The modification is performed under conditions in which the reagent does not cross the permeability barrier. The large effect on the intracellular pH dependence of sulfate transport suggests that a single carboxyl group can at different times be in contact with the aqueous medium on each side of the permeability barrier.

Anion Exchange Protein 1, Erythrocyte↗

PubMed1997

Suggested modifications to the Duke criteria for the clinical diagnosis of native valve and prosthetic valve endocarditis: analysis of 118 pathologically proven cases.

We analyzed 118 consecutive cases of pathologically proven infective endocarditis (100 cases of native valve endocarditis [NVE] and 18 cases of prosthetic valve endocarditis [PVE]) with use of the Beth Israel criteria, the Duke criteria, and our suggested modifications of the Duke criteria; we found improved diagnostic sensitivity with our modifications. These modifications included the following additional minor criteria: the presence of newly diagnosed clubbing, splenomegaly, splinter hemorrhages, and petechiae; a high erythrocyte sedimentation rate; a high C-reactive protein level; and the presence of central nonfeeding lines, peripheral lines, and microscopic hematuria. Analysis of the pathologically proven cases of NVE showed that 64% were probable by the Beth Israel criteria, 83% were definite by the Duke criteria, and 94% were definite by our modified Duke criteria. For the pathologically proven cases of PVE, 50% were probable by the Beth Israel criteria, 50% were definite by the Duke criteria, and 89% were definite by our modified Duke criteria. All cases of NVE and PVE rejected by the Duke criteria remained rejected by our modifications. Therefore, our modifications improved diagnostic sensitivity while retaining specificity.

Adult↗

PubMed2002

Effects on RNA interference in gene expression (RNAi) in cultured mammalian cells of mismatches and the introduction of chemical modifications at the 3'-ends of siRNAs.

The highly specific posttranscriptional silencing of gene expression induced by double-stranded RNA (dsRNA) is known as RNA interference (RNAi) and has been demonstrated in plants, nematodes, Drosophila, and protozoa, as well as in mammalian cells. The suppression of expression of specific genes by chemically synthesized 21-nucleotide (21-nt) RNA duplexes has been achieved in various lines of mammalian cells, and this technique might prove to be a valuable tool in efforts to analyze biologic functions of genes in mammalian cells. In order to investigate the utility of potential modifications that can be introduced into small interfering RNAs (siRNAs) and also to study their functional anatomy, we synthesized different types of siRNA targeted to mRNA of Jun dimerization protein 2 (JDP2). Our detailed analysis demonstrated that siRNAs with only one mismatch, relative to the target, on the antisense strand had reduced RNAi effect, whereas the corresponding mutation on the sense strand did not interfere with the RNAi. Moreover, one 2-hydroxyethylphosphate (hp) substitution at the 3'-end of the antisense strand but not of the sense strand also prevented RNAi, whereas a related modification at the 3'-end of either strand, using 2'-O,4'-C-ethylene thymidine (eT), which is a component of ethylene-bridge nucleic acids (ENA), completely abolished RNAi. These results support the hypothesis that the two strands have different functions in RNAi in cultured mammalian cells and indicate that their chemical modification of siRNAs at the 3'-end of the sense strand exclusively is possible, without loss of RNAi activity, depending on the type of modification. Because modification at the 3'-end of the antisense strand by hp or eT abolished the RNAi effect, it appears possible that the 3'-end is recognized by the RNA-induced silencing complex (RISC).

Animals↗

PubMed2026

Dogme: a nextflow pipeline for reprocessing nanopore RNA and DNA modifications.

MOTIVATION: Oxford Nanopore (ONT) sequencing allows for the direct detection of RNA and DNA modifications from unamplified nucleic acids, which is a significant advantage over other platforms. However, the rapid updates to ONT basecalling models and the evolving landscape of computational tools for modification detection bring about challenges for reproducible and standardized analyses. To address these challenges, we developed Dogme to automate basecalling, alignment, modification detection, and transcript quantification. Dogme automates the reprocessing of ONT POD5 files by integrating basecalling using Dorado, read mapping using minimap2 and subsequent analysis steps such as running modkit. The pipeline supports three major types of sequencing data-direct RNA (dRNA), complementary DNA (cDNA), and genomic DNA (gDNA). Dogme facilitates detection of diverse RNA modifications supported by Dorado such as N6-methyladenosine (m6A), 5-methylcytosine (m5C), inosine, pseudouridine, 2'-O-methylation (Nm) and DNA methylation, while concurrently quantifying full-length transcript isoforms LR-Kallisto for transcript quantification for dRNA and cDNA. RESULTS: We applied Dogme to three separate mouse C2C12 myoblast replicates using direct RNA sequencing on MinION flow cells. We detected 96 603 m6A, 43 476 m5C, 8829 inosine, 10 055 pseudouridine, and 30 320 Nm sites in three biological replicates. The pipeline produced reproducible modification profiles and transcript expression levels across replicates, demonstrating its utility for integrative long-read transcriptomic and epigenomic analyses. AVAILABILITY AND IMPLEMENTATION: Dogme is implemented in Nextflow and is freely available under the MIT license at https://github.com/mortazavilab/dogme, with documentation provided for installation and usage.

RNA↗

PubMed1987

The binding efficiency of polyclonal and monoclonal antibodies to DNA modified with benzo[a]pyrene diol epoxide is dependent on the level of modification. Implications for quantitation of benzo[a]pyrene-DNA adducts in vivo.

A number of polyclonal antibodies specific for DNA modified with (+/-)trans-7,8-dihydroxy-anti-9,10-epoxy-7,8,9,10-tetrahydrobenzo[a]pyre ne (BPDE) were obtained from the sera of New Zealand white rabbits immunized with BPDE-DNA, complexed with methylated bovine serum albumin (mBSA). Monoclonal antibodies were developed by fusion of mouse myeloma cells with spleen cells isolated from BALB/c mice immunized with the same complex of BPDE-DNA and mBSA. These antibodies have been characterized for specificity in a highly sensitive, enzyme-linked immunosorbent assay (ELISA). All antibodies showed a very high affinity for single-stranded BPDE-DNA, but had lower affinity towards native BPDE-DNA. The affinity for the free mononucleoside BPDE-dG was at least 100-fold lower than that for BPDE-DNA, and no affinity was detected for BP tetrols or DNA modified with N-acetoxy-N-acetyl-2-aminofluorene. A high cross reactivity was observed with DNA modified with (+/-)-trans-1,2-dihydroxy-anti-3,4-epoxy-1,2,3,4-tetrahydrochrysene++ +. Using five different antibodies, monoclonal or polyclonal, we observed that the antibody affinity for BPDE-DNA was dependent on the level of modification; in the competitive ELISA as little as 4 fmol BPDE-DNA (50 pmol/micrograms) was sufficient for 50% inhibition with our best antisera, but 17 fmol of the adduct was required when [3H]BPDE-DNA of low modification (1-10 fmol/micrograms) was used as inhibitor. When samples of [3H]BP-DNA isolated from the livers of mice, treated i.p. with different doses of [3H]BP were examined by competitive ELISA and calibrated with [3H]BPDE-DNA of low modification (1-10 fmol/micrograms), binding values calculated from the immunoassay were in good agreement with those obtained from radioactivity measurements. In contrast, when this DNA was quantitated in competitive ELISA using highly modified BPDE-DNA as standards, values by ELISA were 20-40% of those obtained by radioactivity. These results indicate that the use of serially diluted BPDE-DNA of high modification as standard competitor in the ELISA will lead to erroneous results in the measurement of adducts in DNAs modified to a low extent (biological samples). The property of antisera specific for BP-DNA, recognizing highly modified DNA more efficiently than DNA modified to a low extent, may be common to all antisera elicited against highly modified DNA immunogens. Therefore we conclude that antibody affinity must be tested also with DNA samples of low modification, obtained either in vitro or in vivo.

2-Acetylaminofluorene↗

PubMed1998

Modifications of U2 snRNA are required for snRNP assembly and pre-mRNA splicing.

Among the spliceosomal snRNAs, U2 has the most extensive modifications, including a 5' trimethyl guanosine (TMG) cap, ten 2'-O-methylated residues and 13 pseudouridines. At short times after injection, cellularly derived (modified) U2 but not synthetic (unmodified) U2 rescues splicing in Xenopus oocytes depleted of endogenous U2 by RNase H targeting. After prolonged reconstitution, synthetic U2 regenerates splicing activity; a correlation between the extent of U2 modification and U2 function in splicing is observed. Moreover, 5-fluorouridine-containing U2 RNA, a potent inhibitor of U2 pseudouridylation, specifically abolishes rescue by synthetic U2, while rescue by cellularly derived U2 is not affected. By creating chimeric U2 molecules in which some sequences are from cellularly derived U2 and others are from in vitro transcribed U2, we demonstrate that the functionally important modifications reside within the 27 nucleotides at the 5' end of U2. We further show that 2'-O-methylation and pseudouridylation activities reside in the nucleus and that the 5' TMG cap is not necessary for internal modification but is crucial for splicing activity. Native gel analysis reveals that unmodified U2 is not incorporated into the spliceosome. Examination of the U2 protein profile and glycerol-gradient analysis argue that U2 modifications directly contribute to conversion of the 12S to the 17S U2 snRNP particle, which is essential for spliceosome assembly.

Animals↗

PubMed2002

Transcription factor Sp3 is silenced through SUMO modification by PIAS1.

Sp3 is a ubiquitous transcription factor closely related to Sp1. Here we show that Sp3 is a target for SUMO modification in vivo and in vitro. SUMO modification of Sp3 occurs at a single lysine located between the second glutamine-rich activation domain and the DNA-binding domain. Mutational analyses identified the sequence IKXE as essential for SUMO conjugation to Sp3. We identified the protein inhibitor of activated STAT1 (PIAS1) as an interaction partner of Sp3 and Ubc9. Moreover, PIAS1 strongly stimulated SUMO conjugation to Sp3, thus acting as an E3 ligase for SUMO conjugation to Sp3. All mutations that prevented SUMO modification in vitro strongly enhanced the transcriptional activity of Sp3, showing that SUMO modification silences Sp3 activity. SUMO-modified Sp3 bound to DNA with similar specificity and affinity as unmodified Sp3. However, DNA-bound Sp3 did not act as a substrate for SUMO modification.

Animals↗

PubMed2005

Using remote assessment to provide home modification services to underserved elders.

PURPOSE: Although remote home assessment would enable specialists to prescribe home modifications for anyone, anywhere, the strategy is dependent on the ability to provide specialists with the same information as an in-home assessment. The purpose of this paper is to document that remote assessment is feasible and concurs largely with traditional in-home assessment based on expert judgment. DESIGN AND METHODS: We compared two new remote assessments, a "zero-tech" paper-and-pencil protocol and a "high-tech" televideo protocol, to traditional in-home assessments to determine the equivalence of the remote and in-home assessments. We determined equivalence by comparing each of the remote assessments to a traditional in-home assessment in the same home. In-home assessments were conducted by home-modification specialists in all homes. Data collection for the remote protocols was conducted by individuals inexperienced in home modification. Assessment data from the remote protocols were analyzed by specialists to diagnose problems and prescribe solutions. RESULTS: The overall rates of correct problem identification (i.e., Sensitivity + Specificity) were significant (p =.000) for both the remote paper-and-pencil (96.4%) and remote televideo (87.1%) protocols. Similarly, rates of agreement in recommendations of solutions were significant (p =.000) for both remote assessments (78.8% and 77.4%, respectively). IMPLICATIONS: The need for home-modification services, particularly in rural areas, far exceeds the capacity of specialists to provide them. Our findings suggest that remote assessments can potentially be used to identify mobility and safety problems in the home as well as to recommend solutions to those problems. As a result, remote home assessment has the potential to provide underserved elders with access to home-modification services that have heretofore eluded them.

Aged↗

PubMed1984

Modification of telomeric DNA in Trypanosoma brucei; a role in antigenic variation?

Expression of surface antigen genes in Trypanosoma brucei occurs at expression sites located near telomeres. Since only one antigen is produced at a time, a mechanism must exist to prevent the simultaneous activity of multiple expression sites. Here we report that PstI and PvuII restriction sites in silent telomeric antigen genes are partially uncleavable , presumably as a consequence of DNA modification. The modification, which is absent in transcribed genes but returns after gene inactivation, may be specific for telomeric DNA because (1) it is not detected in non-telomeric genes; (2) modification is highest close to the telomere; (3) the level of modification in a telomeric gene is influenced by the size of the telomeric DNA segment downstream. Whether telomere modification is cause or consequence of antigen gene switch-off remains to be determined.

Animals↗

PubMed1985

Nucleotide sequence of the BsuRI restriction-modification system.

The genes of the 5'-GGCC specific BsuRI restriction-modification system of Bacillus subtilis have been cloned and expressed in E. coli and their nucleotide sequence has been determined. The restriction and modification genes code for polypeptides with calculated molecular weights of 66,314 and 49,642, respectively. Both enzymes are coded by the same DNA strand. The restriction gene is upstream of the methylase gene and the coding regions are separated by 780 bp. Analysis of the RNA transcripts by S1-nuclease mapping indicates that the restriction and modification genes are transcribed from different promoters. Comparison of the amino acid sequences revealed no homology between the BsuRI restriction and modification enzymes. There are, however, regions of homology between the BsuRI methylase and two other GGCC specific modification enzymes, the BspRI and SPR methylases.

Bacillus subtilis↗

PubMed1988

Theoretical analysis of 'addressed' chemical modification of DNA.

Chemical "addressed" modification of DNA involves treatment of single-stranded DNA with oligonucleotides complementary to certain target sequences in this DNA and bearing a groupings reactive towards DNA bases. The binding of oligonucleotides can occur both at completely (specific) and incompletely (nonspecific) complementary sites. We analyse the modification of a fragment that is flanked by two target sequences complementary to a given oligonucleotide address, contains no more such targets and has some randomly distributed sites for nonspecific binding. Conditions for the maximum ratio between specific and non-specific modification are determined. We find the probability of both target termini being specifically modified without any non-specific modification occurring within the fragment up to a given moment in time. Quantitative analysis is based on the use of known features of the specific and non-specific binding of an oligonucleotide to DNA sites. This analysis shows the possibility of specific cutting of DNA based on addressed modification.

Base Composition↗

PubMed1993

Endonuclease-sensitive DNA modifications induced by acetone and acetophenone as photosensitizers.

Repair endonucleases, viz. endonuclease III, formamidopyrimidine-DNA glycosylase (FPG protein), endonuclease IV, exonuclease III and UV endonuclease, were used to analyse the modifications induced in bacteriophage PM2 DNA by 333 nm laser irradiation in the presence of acetone or acetophenone. In addition to pyrimidine dimers sensitive to UV endonuclease, 5,6-dihydropyrimidines (sensitive to endonuclease III) and base modifications sensitive to FPG protein were generated. The level of the last in the case of acetone was 50% and in the case of acetophenone 9% of the level of pyrimidine dimers. HPLC analysis of the bases excised by FPG protein revealed that least some of them were 8-hydroxyguanine (7,8-dihydro-8-oxoguanine). In the damage induced by direct excitation of DNA at 254 nm, which was analysed for comparison, the number of FPG protein-sensitive base modifications was only 0.6% of that of the pyrimidine dimers. Mechanistic studies demonstrated that the formation of FPG protein-sensitive modifications did not involve singlet oxygen, as the damage was not increased in D2O as solvent. Hydroxyl radicals, superoxide and H2O2 were also not involved, since the relative number of single strand breaks and of sites of base loss (AP sites) was much lower than in the case of DNA damage induced by hydroxyl radicals and since the presence of SOD or catalase had no effect on the extent of the damage. However, the mechanism did involve an intermediate that was much more efficiently quenched by azide ions than the triplet excited carbonyl compounds and which was possibly a purine radical. Together, the data indicate that excited triplet carbonyl compounds react with DNA not only by triplet-triplet energy transfer yielding pyrimidine dimers, but also by electron transfer yielding preferentially base modifications sensitive to FPG protein, which include 8-hydroxyguanine.

Acetone↗

PubMed1999

Search for differences in post-transcriptional modification patterns of mitochondrial DNA-encoded wild-type and mutant human tRNALys and tRNALeu(UUR).

Post-transcriptional modifications are characteristic features of tRNAs and have been shown in a number of cases to influence both their structural and functional properties, including structure stabilization, amino-acylation and codon recognition. We have developed an approach which allows the investigation of the post-transcriptional modification patterns of human mitochondrial wild-type and mutant tRNAs at both the qualitative and the quantitative levels. Specific tRNA species are long-term labeled in vivo with [32P]orthophosphate, isolated in a highly selective way, enzymatically digested to mononucleotides and then subjected to two-dimensional thin layer chromatographic analysis. The wild-type tRNALysand the corresponding tRNALyscarrying the A8344G mutation associated with the MERRF (Myoclonic Epilepsy with Ragged Red Fibers) syndrome exhibit the same modified nucleotides at the same molar concentrations. By contrast, a quantitatively different modification pattern was observed between the wild-type tRNALeu(UUR)and its counterpart carrying the A3243G mutation associated with the MELAS (Mitochondrial Myopathy, Encephalopathy with Lactic Acidosis and Stroke-like episodes) syndrome, the latter exhibiting a 50% decrease in m2G content. Complementary sequencing of tRNALeu(UUR)has allowed the localization of this modification at position 10 within the D-stem of the tRNA. The decreased level of this modification may have important implications for understanding the molecular mechanism underlying the MELAS-associated mitochondrial dysfunction.

Autoradiography↗

PubMed2002

The high binding affinity of phosphorothioate-modified oligomers for Ff gene 5 protein is moderated by the addition of C-5 propyne or 2'-O-methyl modifications.

One of the problems that hamper the use of antisense DNAs as effective drugs is the non-specific binding of chemically-modified oligonucleotides to cellular proteins. We previously showed that the affinity of a model ssDNA-binding protein, the Ff gene 5 protein (g5p), was >300-fold higher for phosphorothioate-modified DNA (S-DNA) than for unmodified dA(36), consistent with the propensity of S-DNA to bind indiscriminately to proteins. The current work shows that g5p binding is also sensitive to sugar and pyrimidine modifications used in antisense oligomers. Binding affinities of g5p for 10 36mer oligomers were quantitated using solution circular dichroism measurements. The oligomers contained C-5-propyne (prC), 2'-O-methyl (2'-O-Me) or 2'-OH (RNA) groups, alone or combined with the phosphorothioate modification. In agreement with reported increases in antisense activity, the addition of prC or 2'-O-Me modifications substantially reduced the affinity of oligomers for g5p by approximately 2-fold compared with the same DNA oligomer sequences containing only phosphorothioate linkages. That is, such modifications moderated the propensity of the phosphorothioate group to bind tightly to the g5p. The Ff g5p could be a useful model protein for assessing non-specific binding effects of antisense oligomer modifications.

Circular Dichroism↗

PubMed2001

Promotion of triplex formation by N3'-->P5' phosphoramidate modification: thermodynamic and kinetic studies.

I examined the effect of N3'-->P5' phosphoramidate (PN) backbone modification of triplex-forming oligonucleotide (TFO) on the pyrimidine motif triplex formation at neutral pH, a condition where pyrimidine motif triplexes are unstable. Both thermodynamic and kinetic analyses have indicated that the PN modification of TFO increased the binding constant of the pyrimidine motif triplex formation at pH 6.8 by nearly 2 orders of magnitude. Kinetic data have also demonstrated that the observed increase in the binding constant at neutral pH by the PN modification resulted mainly from the considerable decrease in the dissociation rate constant rather than the increase in the association rate constant. The present results certainly support the idea that the PN modification of TFO could be a key modification and may eventually lead to progress in therapeutic applications of the antigene strategy in vivo.

Amides↗

PubMed1997

A prospective, randomized comparison of temperature-controlled vs manually delivered radiofrequency catheter ablation in patients undergoing atrioventricular nodal modification or accessory pathway ablation.

AIMS: In a prospective, randomized study, the effect of temperature control on radiofrequency catheter ablation was compared in 69 patients undergoing atrioventricular nodal modification (n = 32) or ablation of an accessory pathway (n = 37). METHODS AND RESULTS: Thirty-five patients were randomized to temperature control, 34 to manually delivered radiofrequency ablation. The success rate was 92.5% for accessory pathway ablation and 100% for atrioventricular nodal modification. Mapping duration was significantly reduced only in patients undergoing atrioventricular nodal modification. The number of applications was higher for manually delivered ablation in patients undergoing atrioventricular nodal modification (5.6 +/- 1.1 vs 1.9 +/- 0.4, P = 0.004) as was the cumulative energy delivered (5034 +/- 1008 vs 2054 +/- 517 W, P = 0.013) whereas the mean power per application was higher with temperature control (41.4 +/- 1.8 vs 34.1 +/- 1.1 W, P = 0.002). No significant differences in these parameters were found in patients undergoing accessory pathway ablation. Coagulum formation on the catheter tip was observed more often with manually delivered ablation 5.3% vs 0.9%, P = 0.026). The success rate with the initially randomized application mode was higher for temperature control (94.3 vs 61.8%, P = 0.003). CONCLUSIONS: Temperature control during radiofrequency current ablation significantly reduces mapping duration, necessary applications and cumulative energy in atrioventricular nodal modification, but not accessory pathway ablation. Coagulum formation on the catheter tip still occurs but is significantly reduced compared to manually delivered radiofrequency current.

Atrioventricular Node↗