Minimal Dilation Research Articles

Minimal isometric dilations and operator models for the polydisc

For commuting contractions $T_1,\dots,T_n$ acting on a Hilbert space $\mathscr{H}$ with $T=\prod_{i=1}^n T_i$ , we find a necessary and sufficient condition such that $(T_1,\dots,T_n)$ dilates to a commuting tuple of isometries $(V_1,\dots,V_n)$ on the minimal isometric dilation space of T with $V=\prod_{i=1}^nV_i$ being the minimal isometric dilation of T. This isometric dilation provides a commutant lifting of $(T_1, \dots, T_n)$ on the minimal isometric dilation space of T. We construct both Schäffer and Sz. Nagy–Foias-type isometric dilations for $(T_1,\dots,T_n)$ on the minimal dilation spaces of T. Also, a different dilation is constructed when the product T is a $C._0$ contraction, that is, ${T^*}^n \rightarrow 0$ as $n \rightarrow \infty$ . As a consequence of these dilation theorems, we obtain different functional models for $(T_1,\dots,T_n)$ in terms of multiplication operators on vectorial Hardy spaces. One notable fact about our models is that the multipliers are all analytic functions in one variable. The dilation when T is a $C._0$ contraction leads to a conditional factorization of T. Several examples have been constructed.

Intact DNA repair in differentiated cardiomyocytes is essential for maintaining cardiac function in response to pressure overload in mice

Abstract Introduction DNA in every cell is continuously damaged and DNA repair mechanisms are essential for protection against DNA damage-induced aging-related diseases. For example, deficient repair of endogenously generated DNA damage in mice with cardiomyocyte-restricted inactivation of Xpg, is associated with progressive heart failure. Purpose Here we tested the hypothesis that unrepaired DNA damage in differentiated cardiomyocytes increases cardiac vulnerability in response to hemodynamic overload. Methods To increase the burden of spontaneous DNA damage, we generated mice with cardiomyocyte-restricted inactivation of DNA repair endonuclease XPG. At 8 weeks of age, αMHC-Xpgc/- and control (Ctrl) mice were subjected to pressure overload by transverse aortic constriction (TAC). Eight weeks after TAC, left ventricular (LV) function was assessed using echocardiography and hemodynamic measurements, followed by molecular and histological analyses. Results Cardiomyocyte-restricted inactivation of Xpg resulted in systolic as well as diastolic LV dysfunction (Table). TAC-induced LV hypertrophy is similar in both groups (Ctrl 38%; αMHC-Xpgc/- 34%). In Ctrl mice, LV hypertrophy was accompanied by minimal LV dilation and modest changes in systolic and diastolic LV function. Conversely, TAC in αMHC-Xpgc/- produced severe LV dysfunction and resulted in overt congestive heart failure, demonstrated by aggravation of LV dilation, and marked increases in LV end-diastolic pressure, left atrial weight and lung fluid weight, which was accompanied by further increases in the expression levels of the hypertrophic marker genes atrial natriuretic peptide and beta-myosin heavy chain (Table). Moreover, lectin staining revealed a decrease in capillary density and TUNEL staining revealed further elevated levels of myocardial apoptosis. In addition, a significant increase of myocardial collagen content was observed. Conclusion Cardiomyocyte-restricted loss of DNA repair protein XPG increases cardiac vulnerability to develop heart failure in response to pressure overload. These findings underscore the importance of genomic stability for maintenance of cardiac function, not only during basal conditions, but also in response to a pathological stimulus.

Distinguished varieties in a family of domains associated with spectral interpolation and operator theory

We find characterization for the distinguished varieties in the symmetrized polydisc $\mathbb G_n \; (n\geq 2)$ and thus generalize the work [\textit{J. Funct. Anal.}, 266 (2014), 5779 -- 5800] on $\mathbb G_2$ by the author and Shalit. We show that a distinguished variety $\Lambda$ in $\mathbb G_n$ is a part of an algebraic curve, which is a set-theoretic complete intersection, and that $\Lambda$ can be represented by the Taylor joint spectrum of $n-1$ commuting scalar matrices satisfying certain conditions. An $n$-tuple of commuting Hilbert space operators $(S_1, \dots ,S_{n-1},P)$ for which $\Gamma_n=\overline{\mathbb G_n}$ is a spectral set is called a $\Gamma_n$-contraction. To every $\Gamma_n$-contraction $(S_1, \dots ,S_{n-1},P)$ there is a unique operator tuple $(F_1, \dots , F_{n-1})$, called the $\mathcal F_O$-tuple of $(S_1, \dots ,S_{n-1},P)$, satisfying \[ S_i-S_{n-i}^*P=D_PF_iD_P \,,\quad i=1, \dots ,n-1. \] We produce concrete functional model for the pure isometric-operator tuples associated with $\Gamma_n$ and by an application of that model we establish that the $\Gamma_n$-contractions $(S_1, \dots ,S_{n-1},P)$ and $(S_1^*, \dots , S_{n-1}^*,P^*)$ admit normal $\partial \overline{ \Lambda}_{\Sigma}-$dilations for a unique distinguished variety $\Lambda_{\Sigma}$ in $\mathbb G_n$, when $\Lambda_{\Sigma}$ is determined by the $\mathcal F_O$-tuple of $(S_1, \dots ,S_{n-1}, P)$. Further, we show that the dilation of $(S_1^*, \dots ,S_{n-1}^*,P^*)$ is minimal and acts on the minimal unitary dilation space of $P^*$. Also, we show interplay between the distinguished varieties in $\mathbb G_2$ and $\mathbb G_{3}$.

Non-dilated obstructive nephropathy.

Obstructive nephropathy (ON) is a common and reversible cause of post-renal acute kidney injury (AKI) and may be caused by a variety of conditions. It occurs when both the upper urinary tracts are obstructed, or when one tract is obstructed in patients with a solitary kidney. ON is suspected whenever there is evidence of hydronephrosis at imaging. However, not all patients with obstruction develop hydronephrosis and significant obstruction can be present in the absence of hydronephrosis. This syndrome is called non-dilated obstructive uropathy (NDOU). It accounts for about 5% of cases of urinary obstruction and the diagnosis can be challenging. The current paper provides an overview of the literature aiming to identify the main causes of NDOU and its clinical presentation, in order to clarify when to suspect it among AKI cases. A narrative review was performed due to the overall low quality of the available evidence. Only patients with post-renal AKI and a non-dilated or minimal dilation of the intrarenal collecting system were included. As evidenced by our review, NDOU is most prevalent in the fifth and sixth decades of life and affects mainly the male gender. On hospital admission serum creatinine levels are usually very high. Among the most common clinical presentations are oliguria/anuria, abdominal pain, signs of retention such as oedema or pleural effusion, and nausea/vomiting. About three out of four cases of NDOU are due to an ab-extrinsic compression of the ureters caused by retroperitoneal fibrosis or malignant disease. An effective and minimally invasive urinary diversion is obtained with ureteric stenting or a percutaneous nephrostomy. A correct diagnosis of NDOU may be challenging but it is of paramount importance as it can lead to a prompt management with a potential complete resolution of both obstruction and acute renal failure.

Recurrence following percutaneous exclusion of giant coronary pseudoaneurysm: a case report

BackgroundEmergence of coronary giant pseudoaneurysm (PSA) after stent implantation is potentially catastrophic and may end up with life threatening complications if not managed promptly. There is scarcity of data in existing literature with respect to guidelines on the management of coronary PSA following stent implantation. We report the recurrence of coronary PSA following initial percutaneous management of a giant coronary PSA using multiple stent grafts.Case presentationA 38-year-old male who underwent primary angioplasty of the right coronary artery (RCA) about a month back, presented with dull aching precordial chest pain for the last 15 days. A repeat coronary angiography revealed giant coronary PSA in proximal to mid RCA. Considering the significantly large size of the coronary PSA with symptoms of impending rupture, the giant coronary PSA was successfully excluded by implanting three sequentially coronary stent grafts. However, after one and a half months, the patient again presented with a similar kind of dull aching chest pain. We found a recurrence of coronary PSA in a segment of the coronary artery distal to the portion excluded by stent grafts. This recurrent coronary PSA was once again successfully excluded by redeploying two more stent grafts with the help of a guide extension catheter.ConclusionsIn this case, vessel wall injury as a result of aggressive post dilatation using an oversized balloon during the index procedure was the contributor to the giant coronary PSA formation. It usually appears early after the index procedure (within 4 weeks). Though the usual strategy used to exclude coronary aneurysm is by using the minimal number of stent grafts (due to the inherent increased risk of restenosis/thrombosis in stent grafts) in post angioplasty traumatic aneurysm it is prudent to exclude the entire damaged artery by placing stent grafts to prevent recurrence in segments with even minimal dilatation on initial evaluation.

Intact DNA Repair in Differentiated Cardiomyocytes Is Essential for Maintaining Cardiac Function in Response to Pressure Overload in Mice

Introduction: DNA in every cell is continuously damaged and DNA repair mechanisms are essential for protection against DNA damage-induced aging-related diseases. For example, deficient repair of endogenously generated DNA damage in mice with cardiomyocyte-restricted inactivation of Xpg, is associated with progressive heart failure (de Boer et al. Aging Cell 2023). Here we tested the hypothesis that unrepaired DNA damage in differentiated cardiomyocytes increases cardiac vulnerability in response to hemodynamic overload. Methods: At 8 weeks of age, αMHC-Xpgc/- and control (Ctrl) mice were subjected to pressure overload by mild transverse aortic constriction (TAC). Eight weeks after TAC, left ventricular (LV) function was assessed using echocardiography and hemodynamic measurements, followed by histological and molecular analyses. Results: Cardiomyocyte-restricted inactivation of Xpg resulted in systolic as well as diastolic LV dysfunction. TAC-induced LV hypertrophy was similar in both groups (Ctrl 38%; αMHC-Xpgc/- 34%). In Ctrl mice, LV hypertrophy was accompanied by minimal LV dilation and only modest changes in systolic and diastolic LV function. Conversely, TAC in αMHC-Xpgc/- produced severe LV dilation and dysfunction and resulted in overt backward failure, demonstrated by marked increases in LV end-diastolic pressure, left atrial weight and lung fluid weight. These changes were accompanied by further increases in the expression levels of the hypertrophic marker genes atrial natriuretic peptide and beta-myosin heavy chain. Moreover, lectin staining revealed a decrease in capillary density and TUNEL staining revealed further elevated levels of myocardial apoptosis in αMHC-Xpgc/--TAC mice as compared to Ctrl-TAC mice. In addition, a significant increase of myocardial collagen content was observed in αMHC-Xpgc/--TAC but not in Ctrl-TAC mice. Conclusion: Cardiomyocyte-restricted loss of DNA repair protein Xpg increases cardiac vulnerability to develop heart failure in response to pressure-overload. These findings underscore the importance of genomic stability for maintenance of cardiac function, not only under basal conditions, but also during increased cardiac loading conditions. Supported by the Dutch Heart Foundation [Grants 2017B018-ARENA-PRIME; 2021B008-RECONNEXT]. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Variability in the Distinctive Features of Silica Sands in Central Europe

Quality quartz sand is globally utilized in construction due to its availability and economic factors, especially in the production of composite cements. Despite its positive properties, quartz sand also has several disadvantages. The dilation of quartz sand can be technologically significant for certain high-temperature applications. This dilation has a non-continuous character with sharp volume change caused by the phase transformation from β to α SiO2 at temperatures around 573 °C. The extent of dilation depends on various factors such as compaction, grain size, the quantity of sand, as well as the shape and character of the grain and chemical purity, particularly the SiO2 content. In this study, six types of quartz sand from different locations in Central Europe were examined, and the influence of chemical composition and grain shape was correlated with the final dilation of these samples. Evaluation methods included X-ray fluorescence spectroscopy (XRFS), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), differential thermal analysis (DTA), and linear thermal expansion analysis. It was found that angular grains, despite their chemical purity, may exhibit minimal dilation. Conversely, the least suitable combination in terms of dilation appears to be a high SiO2 content and high roundness of grains with a smooth surface.

Dilations for operator-valued quantum measures

This paper concerns the dilations of Banach space operator-valued quantum measures. While the recently developed general dilation theory leads to a projection (idempotent) valued dilation for any quantum measure over the projection lattice of a von Neumann algebra that does not contain a Type I2 direct summand, such a dilation does not necessarily guarantee the preservation of countable additivity of the quantum measure. So it remains an open question whether every countably additive B(X)-valued quantum measure can be dilated to a countably additive projection-valued measure. The main purpose of this paper is to prove that such a dilation exists if one of the following two conditions is satisfied: (i) either the underlying Banach space X is ℓp for some 1<p<2 or X has the Schur property, (ii) the quantum measure has bounded p-variation (i.e., the total p-variation is finite) for some 1≤p<∞. These are achieved by establishing a non-commutative version of a minimal dilation theory on the elementary dilation space equipped with an appropriate dilation norm. In particular, we introduce a p-variation norm on the elementary dilation space and prove that every operator-valued quantum measure with bounded p-variation has a projection-valued quantum measure dilation that preserves the boundedness of the p-variation.

Generalized orthogonal measures on the space of unital completely positive maps

Abstract A classical result by Effros connects the barycentric decomposition of a state on a C*-algebra to the disintegration theory of the GNS representation of the state with respect to an orthogonal measure on the state space of the C*-algebra. In this note, we take this approach to the space of unital completely positive maps on a C*-algebra with values in B ⁢ ( H ) {B(H)} , connecting the barycentric decomposition of the unital completely positive map and the disintegration theory of the minimal Stinespring dilation of the same. This generalizes Effros’ work in the non-commutative setting. We do this by introducing a special class of barycentric measures which we call generalized orthogonal measures. We end this note by mentioning some examples of generalized orthogonal measures.

Specific dilation pattern in placental circulation and the NO/sGC role in preeclampsia placental vessels.

Endothelial functions in controlling blood flow in placental circulation are still unclear. The present study compares vascular dilations between placental circulation and other vessels, as well as between normal and preeclampsia placental vessels. Placental, umbilical, and other vessels (cerebral and mesenteric arteries) were collected from humans, sheep, and rats. Vasodilation was tested by JZ101 and DMT. Q-PCR, Western blot, and Elisa were used for molecular experiments. Endothelium-dependent/derived vasodilators, including acetylcholine, bradykinin, prostacyclin, and histamine, mediated no or minimal dilation in placental circulation, which was different from that in other vessels in sheep and rats. There were lower mRNA expressions of muscarinic receptors, histamine receptors, bradykinin receptor 2, endothelial nitric oxide synthesis (eNOS), and less nitric oxide (NO) in human umbilical vessels when compared with placental vessels. Exogenous NO donors (sodium nitroprusside, SNP) and soluble guanylate cyclase (sGC) activators (Bay41-2272) decreased the baseline of vessel tone in placental circulation in humans, sheep, and rats, but not in other arteries. The sGC inhibitor ODQ suppressed the reduced baseline caused by the SNP. The decreased baseline by SNP or Bay41-2272 was higher in placental vessels than in umbilical vessels, suggesting that the role of NO/sGC is more important in the placenta. NO concentrations in preeclampsia placental vessels were lower than those in control, while no significant change was found in umbilical plasma between the two groups. eNOS expression was similar between normal and preeclampsia placental vessels, but phosphorylated eNOS levels were significantly lower in preeclampsia. Following serotonin, SNP or Bay41-2272-mediated dilations were weaker in preeclampsia placental vessels. The decreased amplitude of SNP- or Bay41-2272 at baseline was smaller in preeclampsia. The decreased amplitudes of ODQ + SNP were comparable between the two groups. Despite higher beta sGC expression, sGC activity in the preeclampsia placenta was lower. This study demonstrated that receptor-mediated endothelium-dependent dilation in placental circulation was significantly weaker than other vessels in various species. The results, showed firstly, that exogenous NO played a role in regulating the baseline tone of placental circulation via sGC. Lower NO production and decreased NO/sGC could be one of the reasons for preeclampsia. The findings contribute to understanding specific features of placental circulation and provide information about preeclampsia in placental vessels.

Congenital Mesoblastic Nephroma in a Newborn: Case Report

Background: Congenital mesoblastic nephroma (CMN) is a rare mesenchymal renal tumor of the newborn. The objective of this study was to review the clinical particularities, paraclinical and therapeutic characteristics of this tumor. It is about a case report of pediatric patient admitted to a Pediatric Neonatal Reanimation, A. Harouchi Hospital, Ibn Rochd university Hospital centre, Casablanca. Results: We report the observation of a 4-day premature newborn who was hospitalized for exploration of an abdominal mass occupying the right flank since birth. Abdominal ultrasonography revealed a predominantly fleshy right solidocystic renal mass, a site of calcifications laminating the cortex, measuring 57x33x58, with minimal pyelocaliceal dilatation and diffuse infiltration of perrenal fat. The CT scan revealed a kidney increased in size, seat of a voluminous mass rather well limited, of tissue density, heterogeneous, seat of necrosis, realizing a sign of the spur, measuring 40x47x58mm. The diagnosis was confirmed by a kidney biopsy. Conclusion: Mesoblastic nephroma is considered a benign tumor. The diagnosis is discussed on the basis of clinical data, ultrasound and CT scan. Surgery is the primary treatment for NMC and is based on extended nephrectomy. Most patients with NMC have a favorable outcome, the overall prognosis is very good.

Naimark dilations of qubit POVMs and joint measurements

Measurement incompatibility is one of the cornerstones of quantum theory. This phenomenon appears in many forms, of which the concept of non-joint measurability has received considerable attention in the recent years. In order to characterise this non-classical phenomenon, various analytical and numerical methods have been developed. The analytical approaches have mostly concentrated on the qubit case, as well as to scenarios involving sets of measurements with symmetries, such as position and momentum or sets of mutually unbiased bases. The numerical methods can, in principle, decide any finite-dimensional and discrete joint measurability problem, but they naturally have practical limitations in terms of computational power. These methods exclusively start from a given set of measurements and ask whether the set possesses incompatibility. Here, we take a complementary approach by asking which measurements are compatible with a given measurement. It turns out, that this question can be answered in full generality through a minimal Naimark dilation of the given measurement: the set of interest is exactly those measurements that have a block-diagonal representation in such dilation. We demonstrate the use of the technique through various qubit examples, leading to an alternative characterisation of all compatible pairs of binary qubit measurements, which retrieves the celebrated Busch criterion. We further apply the technique to special examples of trinary and continuous qubit measurements.

A Product Formula for Homogeneous Characteristic Functions

A bounded linear operator T on a Hilbert space is said to be homogeneous if $$\varphi (T)$$ is unitarily equivalent to T for all $$\varphi $$ in the group Möb of bi-holomorphic automorphisms of the unit disc. A projective unitary representation $$\sigma $$ of Möb is said to be associated with an operator T if $$\varphi (T)= \sigma (\varphi )^* T \sigma (\varphi )$$ for all $$\varphi $$ in Möb. In this paper, we develop a Möbius equivariant version of the Sz.-Nagy–Foias model theory for completely non-unitary (cnu) contractions. As an application, we prove that if T is a cnu contraction with associated (projective unitary) representation $$\sigma $$ , then there is a unique projective unitary representation $${\hat{\sigma }}$$ , extending $$\sigma $$ , associated with the minimal unitary dilation of T. The representation $${\hat{\sigma }}$$ is given in terms of $$\sigma $$ by the formula $$\begin{aligned} {\hat{\sigma }} = (\pi \otimes D_1^+) \oplus \sigma \oplus (\pi _*\otimes D_1^-), \end{aligned}$$ where $$D_1^\pm $$ are two unitary representations (one holomorphic and the other anti-holomorphic) living on the Hardy space $$H^2({\mathbb {D}})$$ , and $$\pi , \pi _*$$ are representations of Möb living on the two defect spaces of T defined explicitly in terms of $$\sigma $$ . Moreover, a cnu contraction T has an associated representation if and only if its Sz.-Nagy–Foias characteristic function $$\theta _T$$ has the product form $$\theta _T(z) = \pi _*(\varphi _z)^* \theta _T(0) \pi (\varphi _z),$$ $$z\in {\mathbb {D}}$$ , where $$\varphi _z$$ is the involution in Möb mapping z to 0. We obtain a concrete realization of this product formula for a large subclass of homogeneous cnu contractions from the Cowen–Douglas class.

Evaluation of the self-expanding effect of carotid stents in the early postoperative period.

To evaluate the expansion effect of self-expandable stents during the first week after carotid artery stenting (CAS) procedure and to examine the variation of the effect according to the carotid plaque type. Seventy stenotic carotid arteries of 69 patients were stented by using self-expanding Wallstents with diameters of 7 and 9mm, after detection of stenosis and plaque type by Doppler ultrasonography. Post-stent aggressive ballooning was avoided and residual stenosis rates were measured with digital subtraction angiography. After the stenting procedure, the caudal, narrowest, and cranial diameters of stents were measured with ultrasonography at 30min, first day and first week. Stent diameter increase and change according to plaque type were evaluated. Two-way repeated measure ANOVA test was used for statistical analysis. A significant increase was observed in the mean stent diameter in the three stent regions (caudal, narrow, and cranial) from the 30th minute to the first and seventh days (p < 0.001). The most prominent stent expansion occurred in the cranial and narrow segments within the first day. In the narrow stent region; Stent diameter increase between 30th minute-first day, 30th minute-first week, and first day-first week were all significant (p < 0.001). At 30min, first day, and first week, no significant difference was detected between plaque type and stent expansion in caudal, narrow, and cranial regions (p = 0.286). We think that keeping the lumen patency limited to 30% residual stenosis after CAS procedure by applying minimal post-stenting balloon dilatation and leaving the remaining lumen expansion to the self-expanding feature of the Wallstent might be a sensible approach in order to avoid embolic events and excessive carotid sinus reactions (CSR).

Search of Fractal Space-Filling Curves with Minimal Dilation

We introduce an algorithm for a search of extremal fractal curves in large curve classes. It heavily uses SAT-solvers—heuristic algorithms that find models for CNF boolean formulas. Our algorithm was implemented and applied to the search of fractal surjective curves \(\gamma :[0,1]\rightarrow [0,1]^d\) with minimal dilation $$\begin{aligned} \sup _{t_1<t_2}\frac{\Vert \gamma (t_2)-\gamma (t_1)\Vert ^d}{t_2-t_1}. \end{aligned}$$We report new results of that search in the case of Euclidean norm. We have found a new curve that we call “YE”, a self-similar (monofractal) plane curve of genus \(5\times 5\) with dilation \(5+{43}/{73}=5.5890\ldots \) In dimension 3 we have found facet-gated bifractals (which we call “Spring”) of genus \(2\times 2\times 2\) with dilation \(<17\). In dimension 4 we obtained that there is a curve with dilation \(<62\). Some lower bounds on the dilation for wider classes of cubically decomposable curves are proven.

Dilation, functional model and a complete unitary invariant for C.0Γn-contractions

A commuting tuple of operators [Formula: see text], defined on a Hilbert space [Formula: see text], for which the closed symmetrized polydisc [Formula: see text] is a spectral set, is called a [Formula: see text]-contraction. A [Formula: see text]-contraction is said to be pure or [Formula: see text] if [Formula: see text] is [Formula: see text], that is, if [Formula: see text] strongly as [Formula: see text]. We show that for any [Formula: see text]-contraction [Formula: see text], there is a unique operator tuple [Formula: see text] that satisfies the operator identities [Formula: see text] This unique tuple is called the fundamental operator tuple or [Formula: see text]-tuple of [Formula: see text]. With the help of the [Formula: see text]-tuple, we construct an operator model for a [Formula: see text] [Formula: see text]-contraction and show that there exist [Formula: see text] operators [Formula: see text] such that each [Formula: see text] can be represented as [Formula: see text]. We find an explicit minimal dilation for a class of [Formula: see text] [Formula: see text]-contractions whose [Formula: see text]-tuples satisfy a certain condition. Also, we establish that the [Formula: see text]-tuple of [Formula: see text] together with the characteristic function of [Formula: see text] constitutes a complete unitary invariant for the [Formula: see text] [Formula: see text]-contractions. The entire program is an analog of the Sz.-Nagy–Foias theory for [Formula: see text] contractions.

S1871 A Case of Ketamine-Induced Cholangiopathy: A Novel Diagnosis Associated With Chronic Recreational Ketamine Use

Introduction: Ketamine, an analgesic commonly used for procedural sedation, has become a popular agent for recreational use among young adults. The diagnosis of ketamine-induced cholangiopathy is uncommon. We report a case of a young adult with clinical and radiological features consistent with cholangiopathy induced by chronic ketamine use. Case Description/Methods: A 19-year-old female with past medical history of peptic ulcer disease presented to emergency department (ED) with one year history of severe epigastric abdominal pain. On further questioning, patient reported chronic recreational ketamine use. Physical exam revealed mild epigastric and RUQ tenderness. Liver function test demonstrated elevated alkaline phosphatase of 174 U/L, AST of 237 U/L and ALT of 224 U/L. All other hematology and chemistry results were within normal limits. RUQ ultrasound showed minimally dilated common bile duct (CBD). An MRCP was obtained, showing mild-to-moderate dilatation of intra-/extra-hepatic bile ducts and dilated cystic duct (CD) without obvious intraductal calculi (Figure A). Endoscopic ultrasonography (EUS) was performed showing dilatation of CBD, minimal dilatation of common hepatic duct, and minimal dilatation of CD, once again without obvious calculi (Figure B). These imaging findings are compatible with ketamine-induced cholangiopathy. After being admitted for 6 days, the patient demonstrated significant improvement in her abdominal pain, with gradually improving liver test values. She was discharged with the recommendation to abstain from ketamine use and outpatient gastroenterology follow-up. Discussion: Chronic exposure to ketamine has been known to cause urologic injury, referred to as ketamine-induced ulcerative cystitis. In comparison to the urologic complications of chronic ketamine use, its effects on the biliary system have been less commonly reported. Existing reports have mostly come from regions of Asia where recreational ketamine use is more prevalent. The nonspecific gastrointestinal symptoms that are typically reported by patients with ketamine-induced cholangiopathy may make the diagnosis more challenging to recognize. Due to increasing recreational ketamine use among young adults in recent years, cases of ketamine-induced cholangiopathy are likely to rise. Therefore, a better understanding of the clinical and radiological features of this condition are needed to allow for prompt recognition of ketamine-induced cholangiopathy.Figure 1.: A. MRCP image showing mild-to-moderate dilatation of the intrahepatic and extrahepatic bile ducts and dilatation of the cystic duct. There are no visible stones or evidence of other etiology for the dilatation. B. EUS image displaying CBD dilatation measuring up to 10.6 mm in the head region, with smooth tapering to the ampulla where it measured 2.7 mm.

S3001 Fighting the Odds: A 31-Year-Old Long-Term Survivor of a Kasai Procedure With a Native Liver

Introduction: Congenital biliary atresia is a leading cause of neonatal cholestasis and is a common indication for liver transplantation world wide. The Kasai is a surgical procedure (hepatoportoenterostomy) involving radical excision of the biliary ducts and helps reestablish bile flow and attempts to prevent biliary cirrhosis. Surgical correction can prolong life but almost 80% of patients will require a liver transplant and almost half require surgery before the age of 2. The 20 year survival rate with native liver is less than 45%. We present a unique case of a 31 year old male with biliary atresia who underwent the Kasai Procedure and has still not required a liver transplant despite his age. Case Description/Methods: This is a 31 year old male with a known history of having biliary atresia status post Kasai procedure performed at (5 weeks old) presented for evaluation of abdominal pain. On the physical exam, he had jaundice and abdominal distention. His labs were pertinent for a total bilirubin of 3.1, alkaline phosphatase 187, AST 50, ALT 84, platelets 88, INR of 1.07 and albumin 4.2. An MRCP was performed to rule out cholangitis which showed postoperative changes of Kasai procedure, minimal intrahepatic duct dilation with marked left lobe atrophy and sequelae of hypertension. He was treated with a course of intravenous antibiotic therapy and was diagnosed with cholangitis secondary to biliary stasis from his previous Kasai procedure. He was later followed by a Hepatologist who performed a fibroscan and diagnosed the patient with F4 fibrosis with Steatosis of S1 consistent with cirrhosis. His MELD score was noted to be 10 and he was placed on ursodiol. A screening EGD was performed which showed grade 2 esophageal varices. The patient’s plan is to eventually undergo a liver transplant in the near future. (figure) Discussion: Common complications of patients with a prior Kasai include recurrent cholangitis, portal hypertension, and synthetic liver dysfunction which was seen in our patient. Prior case reports have shown that very few patients have survived longer than 20 years without a liver transplant. It is important for gastroenterologists to know the long term side effects and complications that can be seen in these patients as they transition to adulthood. Our case highlights a rare case of a 31 year old male who survived against all odds and still has not required a liver transplant. To our knowledge and after an extensive literature review, this is the longest survivor to date in the US.Figure 1.: MRCP showing evidence of Kasai Procedure.

C44 VENTRICULAR TACHYCARDIA IN PATIENT WITH PSEUDOISCHEMIC VENTRICULAR SCAR

Abstract We describe a case of 76 years old men. He was referred to emergency room for chest pain and short of breath. The medical history escluded pre–existent miocardial infarction, no history of fever and chest pain has been declared,.The electrocardiogram (ECG) showed a 200 pbm tachycardia with right bundle branch and right axial deviation. The transition was in V4 (Fig. 1). The tachycardia was not tolerated and after ineffective administration of amiodarone, the tachycardia was terminated by DC shock (200 J synchronized). We performed an echocardiogram with evidence of minimal ventricular dilatation, the inferior–posterior–lateral akinesia, inferior–posterior scar and severe reduction of ejection fraction (about 30%). For better characterization of the scar, we performed cardio magnetic resonanc imaging with evidence of significative thinning of the left ventricle free wall and trasmural LGE of the of left ventricle free wall suggest ischemic myocardial injury (Fig. 2 a,b,c,d,e). The coronary arteriography was performed without evidence of critical coronary stenosis.We decide to implant a single lead ICD. After one month, because of recurrence of tachycardia, we performed the electrophysiological study. We induced clinical ventricular tachycardia and the electroanatomical mapping highlighted an area of anomalous potentials extended in the infero–posterior and lower–basal region more at the epicardial level. In these areas, at the epicardial level, late potentials were highlighted and the ablation performed making the tachycardia no longer inducible. Despite of evidence of pseudo–ischemic scar localized at the basal portion of ventricle at the cardiac MRI, no critical coronary stenosis has been demonstrated and the arrhythmogenic substrate was exclusively epicardic. The preliminary hypothesis was a MINOCA, not of recent onset considering the negativity of myocardial enzymes at the admission and the absence of acute ischemic changes on post cardioversion ECG.We have therefore also considered forms of previous extensive myocarditis however with the limited longitudinal extension. From what has been described in the literature, the MRI images could also be attributable to a form of left ventricle arrhythmogenic dysplasia even in the absence of involvement of the apical portions. Forms of infiltrative cardiomyopathies such as sarcoidosis should be excluded due to the lack of involvement of the interventricular septum.

Relating Symmetrizations of Convex Bodies: Once More the Golden Ratio

Similar to the arithmetic-harmonic mean inequality for numbers, the harmonic mean of two convex sets K and C is always contained in their arithmetic mean. The harmonic and arithmetic means of C and – C define two different symmetrizations of C, each keeping some useful properties of the original set. We investigate the relations of such symmetrizations, involving a suitable measure of asymmetry—the Minkowski asymmetry, which, besides other advantages, is polynomial time computable for (reasonably given) polytopes. The Minkowski asymmetry measures the minimal dilatation factor needed to cover a set C by a translate of its negative. Its values range between 1 and the dimension of C, attaining 1 if and only if C is symmetric and if and only if C is a simplex. Restricting to planar compact, convex sets, positioned so that the translation in the definition of the Minkowski asymmetry is 0, we show that if the asymmetry of C is greater than the golden ratio , then the harmonic mean of C and – C is a subset of a dilatate of their arithmetic mean with a dilatation factor strictly less than 1; and for any asymmetry less than the golden ratio, there exists a set C with the given asymmetry value, such that the considered dilatation factor cannot be less than 1.