Pearls and Pitfalls of Pulsed Field Ablation

Stefan Hartl,Nico Reinsch,Anna Füting,Kars Neven 대한심장학회 2023 Korean Circulation Journal Vol.53 No.5

Pulsed field ablation (PFA) was recently rediscovered as an emerging treatment modality for the ablation of cardiac arrhythmias. Ultra-short high voltage pulses are leading to irreversible electroporation of cardiac cells subsequently resulting in cell death. Current literature of PFA for pulmonary vein isolation (PVI) consistently reported excellent acute and long-term efficacy along with a very low adverse event rate. The undeniable benefit of the novel ablation technique is that cardiac cells are more susceptible to electrical fields whereas surrounding structures such as the pulmonary veins, the phrenic nerve or the esophagus are not, or if at all, minimally affected, which results in a favorable safety profile that is expected to be superior to the current standard of care without compromising efficacy. Nevertheless, the exact mechanisms of electroporation are not yet entirely understood on a cellular basis and pulsed electrical field protocols of different manufactures are not comparable among one another and require their own validation for each indication. Importantly, randomized controlled trials and comparative data to current standard of care modalities, such as radiofrequency- or cryoballoon ablation, are still missing. This review focuses on the “pearls” and “pitfalls” of PFA, a technology that has the potential to become the future leading energy source for PVI and beyond.

In-situ Observations of Lubricant Film Thickness Distribution in Mixed EHD Point Contacts

M. HARTL,I. K?UPKA,M. LI?KA 한국트라이볼로지학회 2002 한국트라이볼로지학회 학술대회 Vol.2002 No.10

This paper presents an experimental study of the effect of rolling speed and surface roughness on the mixed elastohydrodynamic (EHD) lubrication characteristics for point contact formed between a real, random, rough surface, steel ball and smooth glass disc. The Thin Film Colorimetic Interferometry measurement technique has been extended to give detailed information about in-contact deformation of the micro geometry. It has enabled to derive the amplitude reduction curve that shows progressive recovering of ball roughness features with increasing speed.

Dosage Effect of Transposable Element

Kim, Jong Bong,Hartl, Daniel L 한국유전학회 1989 Genes & Genomics Vol.11 No.4

Transposable element mariner는 D. mauritiana, D. simulans 등에 분포하여 생식세포 혹은 체세포 돌연변이를 일으킨다. 즉 이는 X 염색체의 white gene삽입하면 눈의 색을 살구빛으로 변화시키는 Wpch인자로 작용하며 이에 더하여 Mos 인자로 작용하면 생식세포 혹은 발생과정의 체세포에서 WPch 인자를 절단하므로서 원래의 붉은 눈 혹은 모자�揚�눈 색을 나타내게 한다. 그러나 D. simulans에서 Wpch와 Mos 인자를 둘다 가지고 있으나 표현형은 살구빛 눈색의 초파리들을 발견, 분석한 결과 이는 transposable element mariner의 수와 위 치 이동에 따른 dosage effect에 의한 것으로 생각되었다.

Role of breast regression protein 39 (BRP-39)/chitinase 3-like-1 in Th2 and IL-13–induced tissue responses and apoptosis

Lee, Chun Geun,Hartl, Dominik,Lee, Gap Ryol,Koller, Barbara,Matsuura, Hiroshi,Da Silva, Carla A.,Sohn, Myung Hyun,Cohn, Lauren,Homer, Robert J.,Kozhich, Alexander A.,Humbles, Alison,Kearley, Jennifer The Rockefeller University Press 2009 The Journal of experimental medicine Vol.206 No.5

<P>Mouse breast regression protein 39 (BRP-39; Chi3l1) and its human homologue YKL-40 are chitinase-like proteins that lack chitinase activity. Although YKL-40 is expressed in exaggerated quantities and correlates with disease activity in asthma and many other disorders, the biological properties of BRP-39/YKL-40 have only been rudimentarily defined. We describe the generation and characterization of BRP-39<SUP>−/−</SUP> mice, YKL-40 transgenic mice, and mice that lack BRP-39 and produce YKL-40 only in their pulmonary epithelium. Studies of these mice demonstrated that BRP-39<SUP>−/−</SUP> animals have markedly diminished antigen-induced Th2 responses and that epithelial YKL-40 rescues the Th2 responses in these animals. The ability of interleukin13 to induce tissue inflammation and fibrosis was also markedly diminished in the absence of BRP-39. Mechanistic investigations demonstrated that BRP-39 and YKL-40 play an essential role in antigen sensitization and immunoglobulin E induction, stimulate dendritic cell accumulation and activation, and induce alternative macrophage activation. These proteins also inhibit inflammatory cell apoptosis/cell death while inhibiting Fas expression, activating protein kinase B/AKT, and inducing Faim 3. These studies establish novel regulatory roles for BRP-39/YKL-40 in the initiation and effector phases of Th2 inflammation and remodeling and suggest that these proteins are therapeutic targets in Th2- and macrophage-mediated disorders.</P>

Dynamic Pose Tracking Accuracy Improvement via Fusing HTC Vive Trackers and Inertia Measurement Units

Mitchell Weber,Roman Hartl,Michael F. Zäh,Jihyun Lee 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.24 No.9

Virtual reality tracking devices are being investigated for application to motion tracking of robots, human bodies, indoor drones, mobile systems, etc., but most studies so far have been limited to performance analysis of commercialized tracking devices in static conditions. This paper investigated methods for improving the measurement accuracy of dynamic positioning and orientation of the HTC tracker. The signals from the photodiodes in the tracker were extracted and fused together, as well as with external Inertial Measurement Units (IMUs) signals using the Extended Kalman Filter (EKF) and the Unscented Kalman Filter (UKF). Multiple base stations, trackers and IMUs were applied to evaluate the measurement accuracy. Multiple paths were used to test different dynamic operating conditions. The results show that the proposed tracking system can improve accuracy by up to several mm by using the UKF as opposed to the EKF algorithm, increasing the number of base stations, increasing the number of trackers and fusing IMUs.

Inhibition of Protein Glycation by Extracts of Culinary Herbs and Spices

Rebecca P. Dearlove,Phillip Greenspan,Diane K. Hartle,Ruthann B. Swanson,James L. Hargrove 한국식품영양과학회 2008 Journal of medicinal food Vol.11 No.2

We tested whether polyphenolic substances in extracts of commercial culinary herbs and spices would inhibitfructose-mediated protein glycation. Extracts of 24 herbs and spices from a local supermarket were tested for the ability toinhibit glycation of albumin. Dry samples were ground and extracted with 10 volumes of 50% ethanol, and total phenoliccontent and ferric reducing antioxidant potential (FRAP) were measured. Aliquots were incubated in triplicate at pH 7.4 with0.25 M fructose and 10 mg/mL fatty acid-free bovine albumin. Fluorescence at 370 nm/440 nm was used as an index of al-bumin glycation. In general, spice extracts inhibited glycation more than herb extracts, but inhibition was correlated with to-tal phenolic content (R2 . 0.89). The most potent inhibitors included extracts of cloves, ground Jamaican allspice, and cin-namon. Potent herbs tested included sage, marjoram, tarragon, and rosemary. Total phenolics were highly correlated withFRAP values (R2 . 0.93). The concentration of phenolics that inhibited glycation by 50% was typically 412 .g/mL. Rela-tive to total phenolic concentration, extracts of powdered ginger and bay leaf were less effective than expected, and blackpepper was more effective. Prevention of protein glycation is an example of the antidiabetic potential for bioactive compoundsin culinary herbs and spices.

Control Elements and Factors in Eukaryotic DNA Replication

( E . Fanning,W . Traut,M . Hartl,P . Alliger,I . Dornreiter,E . Carstens,I . Moarefi ) 한국유전학회 1988 Genes & Genomics Vol.10 No.4

Replication of simian virus 40 (SV40) DNA is controlled by a 64 base-pair viral DNA sequence which serves as the origin of DNA replication, the viral protein T-antigen, which binds to the origin DNA and is required for initiation of each round of replication, and by so far unknown protein(s) provided by the primate host cell. We have recently identified and purified a monkey cell factor (MCF) that binds specifically to DNA sequences in the SV40 origin of replication. MCF also binds to single-stranded DNA and associates with the cellular DNA polymerase alpha. Binding activity of MCF on mutant origin templates is correlated with replication activity of the mutant origins in vivo. The role of MCF in SV40 DNA replication in vitro, binding of MCF to putative cellular origins of replication, and the nature of putative cellular termination sequences are under investigation.

Twenty-Four Hour Urinary C-peptide and Fasting Plasma C-peptide as Indicators of Metabolic Control in 83 Insulin Dependent Diabetic Patients

Hyung Joon Yoo,S. G. Hartling,C. Binder 대한내과학회 1987 The Korean Journal of Internal Medicine Vol.2 No.2

Inhibition of Aromatase and α-Amylase by Flavonoids and Proanthocyanidins from Sorghum bicolor Bran Extracts

James L. Hargrove,Phillip Greenspan,Diane K. Hartle,Christopher Dowd 한국식품영양과학회 2011 Journal of medicinal food Vol.14 No.7

We compared the ability of simple flavonoids and proanthocyanidins in Sorghum bicolor bran extracts to inhibit enzymes in vitro. In particular, aromatase is a target for breast cancer therapy, and inhibition of α-amylase can reduce the glycemic effect of dietary starches. Proanthocyanidin-rich sumac sorghum bran extract inhibited α-amylase at a lower concentration (50% inhibitory concentration [IC50]=1.4 μg/mL) than did proanthocyanidin-free black sorghum bran extract (IC50=11.4 μg/mL). Sumac sorghum bran extract inhibited aromatase activity more strongly than black sorghum bran extract (IC50=12.1 μg/mL vs. 18.8 μg/mL, respectively). Bovine serum albumin (BSA), which binds proanthocyanidins, reduced inhibition by sumac but not black sorghum bran extract. When separated on Sephadex LH-20, sumac sorghum proanthocyanidins inhibited both enzymes but showed reduced inhibition with BSA. Flavonoids from either cultivar had higher IC50 values than proanthocyanidins, and BSA had little effect on their inhibition. Proanthocyanidins and simple flavonoids in LH-20 fractions both inhibited aromatase with mixed kinetics and affected Km and Vmax. The results show that potential health benefits of sorghum bran may include actions of monomeric flavanoids as well as proanthocyanidins.

EMPIRICAL DISTRIBUTIONS OF FOREIGN EXCHANGE RATES UNDER THE FLOATING EXCHANGE RATE SYSTEM

Mohammed F Khayum,Jong C Rhim,Robert J Hartl People&Global Business Association 1996 Global Business and Finance Review Vol.1 No.1

The shape of foreign exchange probability distributions is important in practical applications of theoretical models of international finance. This paper extends previous analyses of the shape of exchange rate distributions by considering a wider range of candidate processes. The results indicate that the logistic distribution provides the best representation of currency returns for four major currencies (the German mark, Japanese yen, Canadian dollar and British pound) against the U. S. dollar between January 1973 and July 1995. These results are significant because they show that in spite of the apparent increase in exchange rate variability during the 1980s and 1990s there has been a stable underlying distribution for major currencies.