Rare Case of Tongue Ischemia Following Cardiopulmonary Bypass

Tongue ischemia is a devastatingly rare disease complication that is typically attributed to cranial arteritis, vasculitis, or prolonged oral intubation that manifests in a patient as a phenotypically black or discolored tongue. There have been less than 10 cases reported in the literature, however, documenting tongue ischemia secondary to shock states requiring high-dose vasopressor support. In these cases, the ischemia or necrosis has typically been limited to the tip of the tongue or has been associated with unilateral disease as bilateral tongue involvement is unlikely given the collateral blood supply of the tongue. To date, the use of imaging modalities to confirm lingual artery disease as the etiology for the presentation of tongue ischemia has been limited. We present a unique case of bilateral tongue ischemia following the use of cardiopulmonary bypass which was confirmed with radiographic evidence demonstrating bilateral lingual artery disease. The nature of case is presented, previous reports of similar cases are reviewed, and potential etiologies of this rare manifestation are discussed.

The Future of Cardiothoracic Surgical Critical Care Medicine as a Medical Science: A Call to Action

Cardiothoracic surgical critical care medicine (CT-CCM) is a medical discipline centered on the perioperative care of diverse groups of patients. With an aging demographic and an increase in burden of chronic diseases the utilization of cardiothoracic surgical critical care units is likely to escalate in the coming decades. Given these projections, it is important to assess the state of cardiothoracic surgical intensive care, to develop goals and objectives for the future, and to identify knowledge gaps in need of scientific inquiry. This two-part review concentrates on CT-CCM as its own subspeciality of critical care and cardiothoracic surgery and provides aspirational goals for its practitioners and scientists. In part one, a list of guiding principles and a call-to-action agenda geared towards growth and promotion of CT-CCM are offered. In part two, an evaluation of selected scientific data is performed, identifying gaps in CT-CCM knowledge, and recommending direction to future scientific endeavors.

A Brief History of Cardiothoracic Surgical Critical Care Medicine in the United States

Cardiothoracic surgical intensive care has developed in response to advances in cardiothoracic surgery. The invention of the cardiopulmonary bypass machine facilitated a motionless and bloodless surgical field and made operations of increasing complexity feasible. By the mid-1950s, the first successful procedures utilizing cardiopulmonary bypass took place. This was soon followed by the establishment of postoperative recovery units, the precursors to current cardiothoracic surgical intensive care units. These developments fostered the emergence of a new medical specialty: the discipline of critical care medicine. Together, surgeons and intensivists transformed the landscape of acute, in-hospital care. It is important to celebrate these achievements by remembering the individuals responsible for their conception. This article describes the early days of cardiothoracic surgery and cardiothoracic intensive care medicine.

Transfusion-Related Acute Lung Injury During Liver Transplantation: A Scoping Review

Liver transplantation is associated with significant blood loss, often requiring massive blood product transfusion. Transfusion-related acute lung injury (TRALI) is a devastating cause of transfusion-related deaths. While reports have investigated the general incidence of TRALI, the incidence of TRALI specifically following transfusion during liver transplant remains unclear. This scoping review summarizes existing literature regarding TRALI during the liver transplantation perioperative period. Databases were searched for all articles and abstracts reporting on TRALI after liver transplantation. Data collected included number of patients studied, patient characteristics, incidences of TRALI, TRALI characteristics, and patient outcomes. The primary outcome investigated was the incidence of TRALI in the setting of liver transplantation. Thirteen full-text citations were included in this review. The incidence of TRALI post-liver transplant was 0.68% (65 of 9,554). Based on reported transfusion data, patients diagnosed with TRALI received an average of 10.92 ± 10.81 units of packed red blood cells (pRBC), 20.05 ± 15.72 units of fresh frozen plasma, and 5.75 ± 10.00 units of platelets. Common interventions following TRALI diagnosis included mechanical ventilation with positive end-expiratory pressure, inhaled high-flow oxygen, inhaled pulmonary vasodilator, and pharmacologic treatment using pressors or inotropes, corticosteroids, or diuretics. Based on reported mortality data, 26.67% of patients (12 of 45) diagnosed with TRALI died during the postoperative period. This scoping review underscores the importance of better understanding the incidence and presentation of TRALI after liver transplant surgery. The clinical implications of these results warrant the development of identification and management strategies for liver transplant patients at increased risk for developing TRALI.

Evaluating the Impact of Pulmonary Artery Obstruction After Lung Transplant Surgery: A Systematic Review and Meta-analysis

BACKGROUND

Pulmonary artery obstruction is an uncommon but significant complication after lung transplantation. Although numerous reports have documented its occurrence, the hemodynamic parameters associated with its presentation and diagnostic considerations remain ill-defined. This systematic review summarizes evidence in the literature surrounding pulmonary artery obstruction after lung transplantation surgery.

METHODS

Databases were searched for all articles and abstracts reporting on pulmonary artery obstruction. Data collected included the number of patients studied, patient characteristics, incidences of pulmonary artery obstruction, and timing and imaging modality used for diagnosis.

RESULTS

Thirty-four full-text citations were included in this review. The point prevalence of pulmonary artery obstruction was 3.66%. The peak pulmonary artery velocity associated with obstruction was found to be 2.60 ± 0.58 m/s. The diameter of the obstructed pulmonary artery predictive of poor outcomes was noted to be 0.78 ± 0.40 cm. The majority of diagnoses were made in the late postoperative period using pulmonary angiogram and transesophageal echocardiography. Overall, 76% of patients (47 of 62) required emergent procedural reintervention, and 23% of patients (14 of 62) diagnosed with pulmonary artery obstruction died during their hospital stay.

CONCLUSIONS

This systematic review underscores the importance of identifying pulmonary artery obstruction immediately after lung transplant surgery. The clinical implications of these results warrant the development of identification and management strategies for early detection of irregularities in pulmonary artery anastomosis in lung transplant patients.

New or Worsened Mitral Regurgitation After Surgical Aortic Valve Replacement: A Systematic Review

BACKGROUND

New or worsened mitral regurgitation (MR) is an uncommon yet serious complication after surgical aortic valve replacement (SAVR). While there have been numerous reports of its occurrence, there is little consensus regarding its presentation and management. This systematic review summarizes the evidence in the current literature surrounding new or worsened MR after SAVR and analyzes its potential implications.

METHODS

Databases were examined for all articles and abstracts reporting on new or worsened MR after SAVR. Data collected included number of patients studied; patient characteristics; incidences of new or worsened MR; timing of diagnosis; and treatment.

RESULTS

Thirty-six full-text citations were included in this review. The prevalence of new or worsened MR after SAVR was 8.4%. Sixteen percent of new MR occurrences were from an organic etiology, and 83% of new MR occurrences were that of a functional etiology. Most diagnoses were made in the late or unspecified postoperative period using echocardiography (range: 0 minutes to 18 years postoperatively). While no patients died from this complication, 7.7% of patients (16 out of 207) required emergent procedural re-intervention.

CONCLUSIONS

This systematic review underscores the importance of identifying new or worsened MR following SAVR and accurate scoring of MR severity to guide treatment. It also outlines the associated clinical measures commonly documented following this complication, and the usefulness of transesophageal echocardiography for the detection of significant MR. These results reflect the current, limited state of the literature on this topic and warrant further investigation into MR detection and management strategies in SAVR patients.

Dermal tattooing following intravenous methylene blue for refractory hypotension after coronary artery bypass grafting

The authors present an image of a middle-aged male after coronary artery bypass grafting who received intravenous methylene blue for refractory hypotension that resulted in dermal tattooing/staining of the venous vasculature of his left shoulder and left upper chest. Republished with permission from: Bhatt AM, Tripathi RS, Moran KR, Papadimos TJ. Dermal tattooing following intravenous methylene blue for refractory hypotension after coronary artery bypass grafting. OPUS 12 Scientist 2012;6(1):11.

Echocardiographic assessment for ventricular assist device placement

While many factors depend on successful implantation and outcome of left ventricular assist devices (LVAD), echocardiography remains an integral part and is vital to the success of this process. Transesophageal echocardiography (TEE) allows interrogation of all the cardiac structures and great vessels. The pre-implantation TEE exam establishes a baseline and may identify potential problems that need palliation. Among these, most significant are aortic insufficiency (AI), intracardiac thrombi, poor right ventricular (RV) function, and intracardiac shunts. The post-implantation exam allows for adequate de-airing of the heart and successful LVAD initiation. The position and flow profiles of the inflow and outflow cannulas of the LVAD may be assessed. Finally, it assists in the astute management and vigilant identification and correction of a number of complications in the immediate post-implantation period. TEE will continue to remain vital to the successful outcomes LVAD patients.

Characterization of the three Arabidopsis thaliana RAD21 cohesins reveals differential responses to ionizing radiation

The RAD21/REC8 gene family has been implicated in sister chromatid cohesion and DNA repair in several organisms. Unlike most eukaryotes, Arabidopsis thaliana has three RAD21 gene homologues, and their cloning and characterization are reported here. All three genes, AtRAD21.1, AtRAD21.2, and AtRAD21.3, are expressed in tissues rich in cells undergoing cell division, and AtRAD21.3 shows the highest relative level of expression. An increase in steady-state levels of AtRAD21.1 transcript was also observed, specifically after the induction of DNA damage. Phenotypic analysis of the atrad21.1 and atrad21.3 mutants revealed that neither of the single mutants was lethal, probably due to the redundancy in function of the AtRAD21 genes. However, AtRAD21.1 plays a critical role in recovery from DNA damage during seed imbibition, prior to germination, as atrad21.1 mutant seeds are hypersensitive to radiation damage.

Plant meiosis: the means to 1N

Meiosis is pivotal in the life history of plants. In addition to providing an opportunity for genetic reassortment, it marks the transition from diploid sporophyte to haploid gametophyte. Recent molecular data suggest that, like animals, plants possess a common set of genes (also conserved in eukaryotic microorganisms) responsible for meiotic recombination and chromosome segregation. However, unlike animals, plant meiocytes do not differentiate from a pool of primordial germ cells, but rather arise de novo from a germline formed from sub-epidermal cells in the anthers and ovules. Mutants defective in the specification of these reproductive cell lines and disrupted in different aspects of the meiotic process are beginning to reveal many features unique to plant meiosis.

The DIF1 gene of Arabidopsis is required for meiotic chromosome segregation and belongs to the REC8/RAD21 cohesin gene family

Cohesins are a group of conserved proteins responsible for cohesion between replicated sister chromatids during mitosis and meiosis and which are implicated in double-strand break repair and meiotic recombination. We describe here the identification and characterisation of an Arabidopsis gene - DETERMINATE, INFERTILE1 (DIF1), which is a homolog of the Schizosaccharomyces pombe REC8/RAD21 cohesin genes, and is essential for meiotic chromosome segregation. Five independent alleles of the DIF1 gene were isolated by transposon mutagenesis, and the mutants show complete male and female sterility. Pollen mother cells (PMCs) of dif1 mutants show multiple meiotic defects which are represented by univalent chromosomes and chromosome fragmentation at metaphase I, and acentric fragments and chromatin bridges in meiosis I and II. Consequently, chromosome segregation is strongly affected, resulting in meiotic products of uneven size, shape and of variable ploidy. The similarities in phenotype, and the sequence homology between DIF1 and the REC8/RAD21 cohesins suggests that cohesin function is largely conserved between eukaryotes and highlights the essential role cohesins play in plant meiosis.

The transposition frequency of Tag1 elements is increased in transgenic Arabidopsis lines

Tag1 was identified as a highly active endogenous transposable element in transgenic Arabidopsis thaliana Landsberg erecta plants carrying the maize transposable element Activator (Ac). Here, we describe experiments designed to determine the basis for the high activity of Tag1. The frequency of transposition of Tag1 elements was compared in lines containing or lacking Ac transposase to assess the effect of Ac transposase on Tag1 activity. Three populations of nontransgenic plants, including nontransformed regenerants, were also analyzed. The high level of activity of Tag1 did not correlate with the presence or absence of Ac transposase but was significantly higher in transgenic lines. This result was maintained through at least six generations after transformation. These data suggest that Tag1 transposition is stimulated by processes that occur during the Agrobacterium transformation and that thereafter remain active. Two Tag1 elements are tightly linked in the Landsberg erecta genome and map to the lower arm of chromosome 1. Tag1 elements were found in only a few A. thaliana ecotypes but were present in four other Arabidopsis species.

Use of Ac as an insertional mutagen in Arabidopsis

A pilot-scale transposon mutagenesis experiment using a modified autonomous Activator (Ac) element, Ac delta Nael, was carried out in Arabidopsis thaliana. Four different transformants carrying Ac elements in different and defined genomic locations were used to generate 1000 plants carrying approximately 500 independent germinal transposition events. These plants were then selfed and the 1000 families screened in tissue culture and soil for phenotypic mutants. Fifty different families segregated mutations in their progeny. Preliminary Southern blot analysis of 29 families which segregated mutant progeny, showed that 28 had a transposed Ac. Six of the families were further tested for linkage between the transposed Ac and the mutant phenotype, and instability of the putatively tagged locus. Two of the mutants were shown to be tagged as they were tightly linked to a transposed Ac, and somatic and germinal reversion was associated with loss of Ac. One other mutant locus was shown to be closely linked to a transposed Ac, and therefore was likely to be tagged. The remaining three mutations were not tagged as they were not linked to a transposed Ac. In two of the tagged mutants Ac had transposed to closely linked sites, while in a third mutant the co-segregating Ac had transposed to a site which was not tightly linked to the donor T-DNA. Multiple insertions into the DIF1 locus were found, due to the preferential transposition of Ac to a linked site.

Development of an efficient two-element transposon tagging system in Arabidopsis thaliana

Modified Ac and Ds elements, in combination with dominant markers (to facilitate monitoring of excision, reinsertion and segregation of the elements) were introduced into Arabidopsis thaliana ecotype Landsberg erecta. The frequencies of somatic and germinal transactivation of the Ds elements were monitored using a streptomycin resistance assay. Transactivation was significantly higher from a stable Ac (sAc) carrying a 537 bp deletion of the CpG-rich 5' untranslated leader of the transposase mRNA than from a wild-type sAc. However, substitution of the central 1.77 kb of the transposase open reading frame (ORF) with a hygromycin resistance marker did not alter the excision frequency of a Ds element. beta-Glucuronidase (GUS) or iaaH markers were linked to the transposase source to allow the identification of plants in which the transposase source had segregated away from the transposed Ds element, eliminating the possibility of somatic or germinal re-activation. Segregation of the excision marker, Ds and sAc was monitored in the progeny of plants showing germinal excision of Ds. 29% of the plants inheriting the excision marker carried a transposed Ds element.

Tissue distribution and change in potato starch phosphorylase mRNA levels in wounded tissue and sprouting tubers

Starch phosphorylase has been cloned from a lambda gt10 cDNA library of potato tuber mRNA. Selected recombinants have been used to demonstrate that phosphorylase mRNA is most abundant in tubers but is also detectable in stolon, root, stem and leaf tissue. The level of phosphorylase mRNA was greatly reduced in wounded stem and tuber tissue. The wounding-induced decrease in phosphorylase mRNA levels is not reversed in the presence of sucrose or mannitol. Regional differences are described in the levels of phosphorylase and patatin mRNA in different parts of the tuber and in the shoot of sprouting potatoes.