Impact of Pre-Existing Mitral Regurgitation Following Left Ventricular Assist Device Implant

OBJECTIVES

Optimal management of significant mitral regurgitation (SMR) during left ventricular assist device (LVAD) placement remains uncertain. This study evaluates the effect of untreated preop SMR on outcomes following LVAD implant.

METHODS

Adults undergoing primary LVAD placement from April 2004 to May 2017 were included. Most recent preop transthoracic echocardiogram (TTE) was used to divide patients into an SMR group with moderate or greater regurgitation, and a group without SMR. Patients underwent LVAD implant without correction of SMR. Primary endpoint was 3-year postoperative survival, with secondary endpoints of length of stay (LOS), resolution of SMR following LVAD on postdischarge (30 day) TTE, and 1-year TTE.

RESULTS

LVAD placement was performed in 270 patients, 172 (63.7%) without SMR and 98 (36.3%) with SMR. There were no differences in comorbidities including diabetes, hypertension, and renal disease. Preop ejection fraction was similar, but a higher pulmonary vascular resistance was recorded in the SMR group (3.6 vs 3.0 Wood Units, P = 0.048). There was no difference in 3-year mortality between the 2 cohorts (log-rank P = 0.0.803). The SMR group had decreased LOS (median 19.5 vs 22 days, P = 0.009). Of the 98 SMR patients, 91 (92.9%) had resolution of SMR to less than moderate at 30 days. At 1 year, 15% of those with preoperative SMR had recurrent SMR.

CONCLUSIONS

Patients undergoing LVAD placement with preop SMR experience no differences in mortality, and a majority experience resolution of MR after implant. Longer-term SMR recurrence and need for mitral intervention with LVAD implant warrant further investigation.

Acute Myeloid Leukemia Presenting as Effusive Constrictive Pericarditis

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AML infrequently causes tamponade and effusive constrictive pericarditis.

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Pericardial cytology has limited sensitivity for malignancy.

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Imaging identifies pericardial effusion and confirms tamponade and constriction.

A connectome of a learning and memory center in the adult Drosophila brain

Understanding memory formation, storage and retrieval requires knowledge of the underlying neuronal circuits. In Drosophila, the mushroom body (MB) is the major site of associative learning. We reconstructed the morphologies and synaptic connections of all 983 neurons within the three functional units, or compartments, that compose the adult MB’s α lobe, using a dataset of isotropic 8 nm voxels collected by focused ion-beam milling scanning electron microscopy. We found that Kenyon cells (KCs), whose sparse activity encodes sensory information, each make multiple en passant synapses to MB output neurons (MBONs) in each compartment. Some MBONs have inputs from all KCs, while others differentially sample sensory modalities. Only 6% of KC>MBON synapses receive a direct synapse from a dopaminergic neuron (DAN). We identified two unanticipated classes of synapses, KC>DAN and DAN>MBON. DAN activation produces a slow depolarization of the MBON in these DAN>MBON synapses and can weaken memory recall.

DOI:http://dx.doi.org/10.7554/eLife.26975.001

Reindarstellung und Charakterisierung des für die Lyse T2-infizierter Zellen verantwortlichen Enzyms

T2-infected cells of E. coli B synthesize an enzyme whose role it is eventually to lyse the cell from within, whereby the new crop of T2-phage is released from it. Procedures for isolating this enzyme in pure form are described. The enzyme is characterized as a lysozyme. It has a molecular weight of 15 200.

Vergleichende Untersuchungen an teilchengebundenem und freiem T2- Lysozym und Kristallisierung beider Enzyme

Serological comparison between particle-bound T 2 phage lysozyme and lysozyme from T 2 phage lysates showed purified preparations of both enzymes to be contaminated to a small extent with T 2 tail fiber protein.

The latter could be removed by gel filtration and does not possess enzymatic activity for its part.

Both lysozymes have been obtained in crystalline form and were studied physico-chemically. They can be assumed to be identical.

Reinigung und Charakterisierung des an T2-Phagen gebundenen Lysozyms

Procedures for the isolation, and some properties of the particle-bound T2 phage lysozyme are described. The enzyme appears to have a higher molecular weight (21 000) and a correspondingly lower specific activity than the homologous free lysozyme, which otherwise it resembles most closely.

QT interval prolongation in end-stage liver disease cannot be explained by nonhepatic factors

INTRODUCTION

QT interval prolongation in patients with end-stage liver disease (ESLD) is common. However, electrolyte abnormalities, renal insufficiency, treatment with QT-prolonging drugs, and other factors known to prolong QT interval independently of liver disease occur frequently in ESLD. Moreover, elevated heart rate may be present in ESLD and result in spurious QTc prolongation if the Bazett formula is used for rate correction. It thus remains unclear whether QT prolongation in ESLD is directly caused by liver failure, or indirectly by these confounding factors.

METHODS

Medical records of all patients (n = 437) who received orthotopic liver transplantation (OLTx) at our institution between 2008 and 2011 were reviewed. Data from 51 patients with available pre-OLTx dobutamine stress echo (DSE), post-OLTx ECG and without nonhepatic factors affecting QT interval duration were analyzed. For each patient, QT versus RR regression line was calculated from ECG tracings obtained during DSE. The QT interval on post-OLTx ECG was compared with the pre-OLTx QT predicted by the regression line for the same RR interval.

RESULTS

QT interval shortened significantly post-OLTx (from 394 ± 47 to 364 ± 45 ms at RR interval 750 ± 144 ms; P < 0.002) when compared using the regression method. Corrected QT intervals calculated by Bazett and Fridericia formulas also shortened. Patients with prolonged QT pre-OLTx had significantly higher INR and lower serum albumin.

CONCLUSION

ESLD impairs ventricular repolarization even in the absence of other known factors affecting repolarization. QT prolongation in ESLD is associated with impaired synthetic liver function.

Reduction in the Effective Barrier Height in Ptsi-P-Si Schottky Diodes by Using Low Energy Ion Implantation

A reduction in the effective barrier height in a PtSi-p-Si Schottky diode was achieved using low energy ion implantation to introduce a shallow p+ layer on a p-Si substrate. After the Schottky diode had been implanted with 3 keV 11B+ ions to a dose of 4 × 1012 ions cm−2, the barrier height was observed to decrease from 0.26 to 0.16eV. The reduction in barrier height correlated well with the boronconcentration found at or near the PtSi-Si interface.

The management of a completely edentulous patient with tardive dyskinesia

Tardive dyskinesia (TD) is an involuntary movement disorder of neurologic origin caused by the use of neuroleptic drugs known as dopamine receptor antagonists. The condition may adversely affect prosthodontic interventions and their possible merits. In this case history description, the rigor of scrupulous history-taking and clinical evaluation of patients with TD or neurologic disorders is emphasized. The successful prosthodontic management of a 74-year-old completely edentulous TD patient is presented, with the conclusion that a prosthodontic intervention may aid symptom reduction and contribute to improvement in a TD patient's quality of life.

Feasibility of myxomatous mitral valve repair using direct leaflet and chordal radiofrequency ablation

OBJECTIVE

Minimally invasive repair of mitral valve prolapse (MVP) causing severe mitral regurgitation (MR) should reduce MR and have chronic durability. Our ex vivo, acute in vivo, and chronic in vivo studies suggest that direct application of radiofrequency ablation (RFA) to mitral leaflets and chordae can effect these repair goals to decrease MR.

METHODS

A total of seven canines were studied to assess the effects of RFA on mitral valve structure and function. RFA was applied ex vivo (n = 1), acutely in vivo using a right lateral thoracotomy and cardiopulmonary bypass (n = 3), and chronically in vivo using percutaneous access to the heart (n = 3). RFA was applied to the mitral valve and its associated chordae. Mitral valve structure and function (in vivo preparations) were then assessed.

RESULTS

Ex vivo application of RFA resulted in qualitative reduction in mitral leaflet surface area and chordal length. Acute in vivo application of RFA to canines found to have MVP causing severe MR demonstrated a 43.7-60.7% statistically significant (P = 0.039) reduction in postablation MR. Chronic, in vivo, percutaneous application of RFA was found to be feasible and the engendered alterations durable.

CONCLUSION

These data suggest that myxomatous mitral valve repair using radiofrequency energy delivered via catheter is feasible.

The Importance of Increased Interatrial Septal Thickness in Patients with Atrial Fibrillation: A Transesophageal Echocardiographic Study

BACKGROUND

Histological studies in animal models have showed that extensive atrial fibrosis or fatty deposition as a result of loss of atrial cardiomyocytes increases the propensity to develop atrial fibrillation (AF). Although several reports have suggested that AF in humans may be a consequence of these mechanisms, no study has correlated the presence of AF with interatrial septal thickness (IAST).

METHODS

Accordingly, we conducted a prospective analysis in 150 consecutive patients referred for transesophageal echocardiography (TEE) for numerous medical reasons. A total of 105 patients (mean age 62 +/- 14 years) who met inclusion and exclusion criteria were included for analysis. Pertinent demographics, echocardiographic chamber dimensions, left ventricular ejection fraction (LVEF), color flow, and spectral Doppler analysis, as well as IAST measured in both systole (S) and diastole (D) were obtained.

RESULTS

When patients with a documented history of AF were compared to patients without documented AF, no statistical difference was noted in terms of patients' height, weight, IVS thickness, or LVEF. Patients with AF had a significantly larger left and right atrial dimensions (P < 0.001), lower left atrial appendage emptying velocities (P < 0.002), and pulmonary vein systolic Doppler signal (P < 0.01). The IAST in systole in patients with AF was 0.75 +/- 0.27 cm versus 0.60 +/- 0.16 cm in patients without AF (P < 0.006) while the IAST in diastole was 0.61 +/- 0.22 cm versus 0.49 +/- 0.12 cm, respectively (P < 0.009). However, no statistical difference was noted between IAST in either systole (P < 0.8) or diastole (P < 0.8) among patients with AF based on the duration of this arrhythmia.

CONCLUSIONS

The results of this prospective TEE study show a statistically significant increase in IAST with the presence of AF independent of patient's age, height, weight, and the degree of IVS thickness. In addition, since no significant valvular abnormalities or compromise in left ventricular systolic function were present, the increase in IAST in patients with AF then suggest possible changes in the material properties of the atrial wall, easily identified by TEE on the interatrial septum, either as a cause or as a result of AF. Since no correlation was found between the degree of IAST and the duration of AF, the presence of IAST not only might identify patients with a higher propensity to have or develop this atrial arrhythmia; but also be a surrogate marker of changes within the components of the atrial wall in AF.

The lived experiences of male on male rape: a review article

The phenomenon of sexual assault upon males has been largely overlooked by society. Opsomming Seksuele geweld van mans teenoor mans is ‘n fenomeen wat grootliks deur die samelewing misken word. *Please note: This is a reduced version of the abstract. Please refer to PDF for full text.

Successful planned pregnancy following endometrial ablation with the YAG laser

In selected patients who previously have undergone YAG laser ablation of the endometrium and who have demonstrated normal intrauterine architecture, pregnancy as a planned event may be a reasonable and safe option.

Cerebral brain metabolism in adult dyslexic subjects assessed with positron emission tomography during performance of an auditory task

Ten dyslexic adults (aged 33.5 +/- 7.3 years, nine men, one woman) and 10 age-, sex- and handedness-matched control subjects (aged 33.6 +/- 5.8 years) performed an auditory syllable discrimination task during 18-fluoro-2-deoxyglucose uptake, and then underwent positron emission tomographic scans. A second normal control group performed an analogous visual discrimination task. Dyslexic subjects experienced greater difficulty and made significantly more errors in performing the auditory task. There were no differences in brain metabolic rates in lateral cortical areas (frontal, parietal, temporal, and occipital lobes). A significant difference emerged in the medial temporal lobe, with dyslexic subjects having significantly higher absolute and relative brain metabolism along an anterior-posterior gradient than normal adults. These data support the hypothesis of altered cerebral processing of auditory stimuli in patients with dyslexia.

Regulation of tubulin levels and microtubule assembly in Saccharomyces cerevisiae: consequences of altered tubulin gene copy number

Microtubule organization in the cytoplasm is in part a function of the number and length of the assembled polymers. The intracellular concentration of tubulin could specify those parameters. Saccharomyces cerevisiae strains constructed with moderately decreased or increased copy numbers of tubulin genes provide an opportunity to study the cellular response to a steady-state change in tubulin concentration. We found no evidence of a mechanism for adjusting tubulin concentrations upward from a deficit, nor did we find a need for such a mechanism: cells with no more than 50% of the wild-type tubulin level were normal with respect to a series of microtubule-dependent properties. Strains with increased copies of both alpha- and beta-tubulin genes, or of alpha-tubulin genes alone, apparently did down regulate their tubulin levels. As a result, they contained greater than normal concentrations of tubulin but much less than predicted from the increase in gene number. Some of this down regulation occurred at the level of protein. These strains were also phenotypically normal. Cells could contain excess alpha-tubulin protein without detectable consequences, but perturbations resulting in excess beta-tubulin genes may have affected microtubule-dependent functions. All of the observed regulation of levels of tubulin can be explained as a response to toxicity associated with excess tubulin proteins, especially if beta-tubulin is much more toxic than alpha-tubulin.

Increased MR signal intensity in skeletal muscle adjacent to malignant tumors: pathologic correlation and clinical relevance

Increased signal on T2-weighted magnetic resonance (MR) images has been demonstrated in skeletal muscle adjacent to neoplasms. Clinical significance of this sign was evaluated by reviewing MR images of 50 patients with musculoskeletal disorders. Increased signal in adjacent muscle was present in 22 patients, including 13 of 25 with primary or secondary malignancies of the musculoskeletal system. Biopsy specimens from the affected area in 11 of these 13 patients revealed edema (n = 8) more often than tumor invasion (n = 3). Nine of 25 patients with nonneoplastic processes had increased signal intensity in skeletal muscle because of infection, myositis, or hematoma. In patients who have not undergone previous surgery or radiation therapy and are without an inflammatory mass, increased signal intensity may be a useful indicator of malignancy.

Development of a differentiated microtubule structure: formation of the chicken erythrocyte marginal band in vivo

The microtubules of mature nucleated erythrocytes are organized into a marginal band that is confined to a single plane at the periphery and that contains essentially the same number of microtubule profiles in each individual cell. Developing erythrocytes can be isolated in homogeneous and synchronously developing populations from chicken embryos. For these reasons, these cells offer a particularly accessible system for study of the pathway leading to a specific microtubule structure in a normal, terminally differentiated animal cell. Along this developmental course, striking changes occur in the properties of the microtubules. Between the postmitotic cell and the formation of the band, a novel arrangement is found: bundles of laterally associated microtubules in each cell, coursing through the cytoplasm but not confined to the periphery. The microtubule organizing centers evident at early stages disappear by the time the band forms. The microtubules in early cells are readily depolymerized by drugs, but that drug sensitivity is lost in the mature cells. The microtubule arrangement of mature cells is faithfully recapitulated after reversible depolymerization, while that of the immature cells is not. Finally, as the band forms, the microtubules and microfilaments increasingly become coaligned. In sum, the microtubules of immature cells have many properties in common with those of cultured cells, but during maturation those properties change. The results suggest that lateral interactions become increasingly important in stabilizing and organizing the microtubules. The properties of marginal band microtubules, and comparable properties of axonal microtubules, may reflect differences between the requirements for cytoskeletal structures of cycling cells and terminally differentiated cells.

Primary thrombosis of the axillary/subclavian vein

We have reported a case of primary thrombosis of the axillary/subclavian vein, also known as the Paget-Schroetter syndrome, complicated by pulmonary embolus. It was successfully treated, along with the pulmonary embolus, with streptokinase infusion.

Purification and properties of a cell-bound bacteriocin from a Bacteroides fragilis strain

A cell-bound bacteriocin was extracted from a Bacteroides fragilis BF-11 strain by treating the cells with a low-molarity buffer (0.01 M Tris-hydrochloride, pH 8.0). Sucrose osmotic shock experiments and ultrasonic lysis of whole cells indicated that the majority of the bacteriocin was located at the cell surface. Culture supernatants contained no significant bacteriocin activity. The bacteriocin was purified by DEAE-cellulose and Sephacryl S200 chromatography and had an apparent molecular weight of approximately 7,000. It was relatively heat stable and was inactivated by proteases. There was a delay of approximately 3.5 h before DNA, RNA, and protein synthesis were inhibited by the bacteriocin. Inhibition of macromolecular synthesis coincided with lysis of the susceptible indicator strain.

The preparation of pyrogen-free foetal calf serum for use in cell and tissue cultured

A method is described for the preparation of foetal calf serum from blood drawn by heart puncture from calf foetuses obtained from a local municipal abattoir. This method differs from that previously described in that the Seitz Supra EK filter pads used in preliminary purification steps have been abandoned. These pads contain significant amounts of pyrogenic bacterial lipopolysaccharides and attempts to depyrogenate them with sodium hypochlorite, hydrogen peroxide and 1% foetal calf serum were unsuccessful. The modified method uses pyrogen-free glass fibre and cellulose fibre filters and provides an entirely satisfactory serum as proved by negative Limulus amoebocyte lysate tests and the excellent growth of cells.

Squamous cell carcinoma of the urachus

The third documented case of primary squamous cell carcinoma of the urachus in the English literature is reported. The interesting coincidental occurrence of the dermoid cyst of the right ovary and a complete longitudinal septum of the vagina and uterine cervix is described.