Atrial tachycardia caused by a superior vena cava fibrillation with conduction block

AbstractAT caused by SVC fibrillationHere, we report a case of a 62-year-old man with a history of incessant atrial tachycardia (AT) for several years. An electrophysiological study revealed rapid and irregular activity in the superior vena cava (SVC), but the surface 12-lead electrocardiogram (ECG) exhibited a relatively regular AT (atrial cycle length=240ms). CARTO mapping of the right atrium (RA) demonstrated that the earliest atrial activation occurred at the posterior septum of the upper RA (the SVC–RA junction). Intravenous administration of 20mg adenosine triphosphate (ATP) led to an acceleration of the SVC–RA conduction up to 1:1 conduction, and the atrial cycle length decreased, consequently converting the AT to transient atrial fibrillation (AF). Application of single radiofrequency energy at the earliest atrial activation site during tachycardia terminated the AT and achieved isolation of the SVC from the RA, despite the continued presence of fibrillation in the SVC. We speculated that SVC fibrillation with spontaneous conduction block at the SVC–RA junction was the cause of this AT

Experimental determination and mathematical modeling of standard shapes of forming autophagosomes

オートファゴソーム標準形態の実験的決定と数理モデル --オートファジーを司る膜構造体の形の特徴を実験と理論で解明--. 京都大学プレスリリース. 2024-01-12.The formation of autophagosomes involves dynamic morphological changes of a phagophore from a flat membrane cisterna into a cup-shaped intermediate and a spherical autophagosome. However, the physical mechanism behind these morphological changes remains elusive. Here, we determine the average shapes of phagophores by statistically investigating three-dimensional electron micrographs of more than 100 phagophores. The results show that the cup-shaped structures adopt a characteristic morphology; they are longitudinally elongated, and the rim is catenoidal with an outwardly recurved shape. To understand these characteristic shapes, we establish a theoretical model of the shape of entire phagophores. The model quantitatively reproduces the average morphology and reveals that the characteristic shape of phagophores is primarily determined by the relative size of the open rim to the total surface area. These results suggest that the seemingly complex morphological changes during autophagosome formation follow a stable path determined by elastic bending energy minimization

Modeling membrane morphological change during autophagosome formation

Autophagy is an intracellular degradation process that is mediated by de novo formation of autophagosomes. Autophagosome formation involves dynamic morphological changes; a disk-shaped membrane cisterna grows, bends to become a cup-shaped structure, and finally develops into a spherical autophagosome. We have constructed a theoretical model that integrates the membrane morphological change and entropic partitioning of putative curvature generators, which we have used to investigate the autophagosome formation process quantitatively. We show that the membrane curvature and the distribution of the curvature generators stabilize disk- and cup-shaped intermediate structures during autophagosome formation, which is quantitatively consistent with in vivo observations. These results suggest that various autophagy proteins with membrane curvature-sensing properties control morphological change by stabilizing these intermediate structures. Our model provides a framework for understanding autophagosome formation.Comment: 33 pages, 8 figure

New route for synthesis of 3- and 5-caffeoylquinic acids via protected quinic acids

Caffeoylquinic acids (CQAs) are a group of the phenylpropanoids produced by certain plant species, which have various biological activities including antioxidant, antibacterial, anticancer, and others. Several synthetic routes have been developed using quinic acids (QAs) and caffeic acid derivatives as starting materials. In this study, alternative pathways of 3- and 5-CQAs preparation using protected quinic acids are described. Both CQAs were achieved by removal of the protecting groups of compound 9 and 18 with acid hydrolysis using dilute HCl solution. These compounds (9 and 18) are novel, resulted from esterification reaction of diacetyl caffeoyl chloride and protected quinic acids. The hydroxyl groups of quinic acid in this case were protected with 2,2-dimethoxy propane or tert-butyldimethylsilyl (TBS) chloride

Massive fields tend to form highly oscillating self-similarly expanding shells

The time evolution of self-interacting spherically symmetric scalar fields in Minkowski spacetime is investigated based on the use of Green's theorem. It is shown that a massive Klein-Gordon field can be characterized by the formation of certain expanding shell structures where all the shells are built up by very high frequency oscillations. This oscillation is found to be modulated by the product of a simple time decaying factor of the form $t^{-{3}/{2}}$ and of an essentially self-similar expansion. Apart from this self-similar expansion the developed shell structure is preserved by the evolution. In particular, the energy transported by each shell appears to be time independent.Comment: 10 pages, to appear in Phys. Rev.

Genetic screen in Drosophila muscle identifies autophagy-mediated T-tubule remodeling and a Rab2 role in autophagy.

Transverse (T)-tubules make-up a specialized network of tubulated muscle cell membranes involved in excitation-contraction coupling for power of contraction. Little is known about how T-tubules maintain highly organized structures and contacts throughout the contractile system despite the ongoing muscle remodeling that occurs with muscle atrophy, damage and aging. We uncovered an essential role for autophagy in T-tubule remodeling with genetic screens of a developmentally regulated remodeling program in Drosophila abdominal muscles. Here, we show that autophagy is both upregulated with and required for progression through T-tubule disassembly stages. Along with known mediators of autophagosome-lysosome fusion, our screens uncovered an unexpected shared role for Rab2 with a broadly conserved function in autophagic clearance. Rab2 localizes to autophagosomes and binds to HOPS complex members, suggesting a direct role in autophagosome tethering/fusion. Together, the high membrane flux with muscle remodeling permits unprecedented analysis both of T-tubule dynamics and fundamental trafficking mechanisms

Vulvar microinvasive squamous cell carcinoma arising in vulvar intraepithelial neoplasia 3 complicated by genital warts and systemic lupus erythematosus: a case report

A patient suffering from long-term systemic lupus erythematosus attended with a complaint of recurrent genital warts. Perineal white-colored skin and a peri-anal papillary protrusion adjacent to the genital warts were biopsied and determined to be vulvar intraepithelial neoplasia (VIN) 3 and microinvasive squamous cell carcinoma (SCC), respectively. These lesions were locally excised. Human papillomavirus (HPV)-6 was detected in these lesions, including in the genital warts, while HPV-56 was detected only in the perineal VIN3 and peri-anal microinvasive SCC.

Acute intraabdominal hemorrhage from an aneurysm on uterine artery

A 36-year-old woman was underwent emergency laparotomy for acute intraabdominal hemorrhage, but bleeding points were not found. Abdominal pains continued after the laparotomy, and rupture of aneurysm on uterine artery was found in angiography. An transcatheter arterial embolization was done for the uterine artery, and the aneurysm was found to disappear in 4-day-after the angiography. Rupture of an aneurysm on uterine artery should be considered for the causes of acute intraabdominal hemorrhage

Production of Neutrinos and Secondary Electrons in Cosmic Sources

We study the individual contribution to secondary lepton production in hadronic interactions of cosmic rays (CRs) including resonances and heavier secondaries. For this purpose we use the same ethodology discussed earlier \cite{Huang07}, namely the Monte Carlo particle collision code DPMJET3.04 to determine the multiplicity spectra of various secondary particles with leptons as the final decay states, that result from inelastic collisions of cosmic-ray protons and Helium nuclei with the interstellar medium of standard composition. By combining the simulation results with parametric models for secondary particle (with resonances included) for incident cosmic-ray energies below a few GeV, where DPMJET appears unreliable, we thus derive production matrices for all stable secondary particles in cosmic-ray interactions with energies up to about 10 PeV. We apply the production matrices to calculate the radio synchrotron radiation of secondary electrons in a young shell-type SNR, RX J1713.7-3946, which is a measure of the age, the spectral index of hadronic cosmic rays, and most importantly the magnetic field strength. We find that the multi-mG fields recently invoked to explain the X-ray flux variations are unlikely to extend over a large fraction of the radio-emitting region, otherwise the spectrum of hadronic cosmic rays in the energy window 0.1-100 GeV must be unusually hard. We also use the production matrices to calculate the muon event rate in an IceCube-like detector that are induced by muon neutrinos from high-energy $\gamma$-ray sources such as RX J1713.7-3946, Vela Jr. and MGRO J2019+37. At muon energies of a few TeV, or in other word, about 10 TeV neutrino energy, an accumulation of data over about five to ten years would allow testing the hadronic origin of TeV $\gamma$-rays.Comment: 21 Pages; 3 Figures; 1 Table; Astroparticle Physics Minor Revise