Massive Spontaneous Hemothorax as a Complication of Apixaban Treatment

INTRODUCTION

Hemothorax is usually related to chest or iatrogenic trauma from procedures such as central lines and thoracentesis. Spontaneous hemothorax is defined as pleural fluid hematocrit greater than 50% of serum hematocrit in absence of natural or iatrogenic trauma affecting the lung or pleural space. Coagulopathy secondary to anticoagulant use has been associated with spontaneous hemothorax. We present a case of spontaneous hemothorax in a patient taking apixaban for venous thromboembolism disease. To our knowledge, this is the first case report of apixaban as a cause of spontaneous hemothorax.

CASE PRESENTATION

A 56-year-old woman with end-stage renal disease (ESRD) was diagnosed with upper extremity deep vein thrombosis (DVT) one month prior to presentation and was started on apixaban presented with dyspnea and left-sided pleuritic chest pain for two weeks. She was found to have left-sided large pleural effusion which was diagnosed as hemothorax. Other etiologies for spontaneous hemothorax were excluded and drainage by 12-French pigtail catheter achieved total resolution of hemothorax in three days.

DISCUSSION

Apixaban is a DOAC used to prevent stroke or thromboembolic events in patients with nonvalvular atrial fibrillation and to prevent recurrent venous thromboembolic disease. Events such as gastrointestinal, intracranial, and soft tissue bleeding have been well-documented. However, bleeding manifestation as hemothorax is seldom reported. Our patient presented with isolated left-sided large pleural effusion which was diagnosed as spontaneous hemothorax. 12-Fr pigtail catheter drainage was effective in the management of our patient and provided total resolution in three days.

CONCLUSION

Spontaneous hemothorax is a rare complication of anticoagulant therapy and might not exhibit the usual radiological signs of traumatic hemothorax. Health care providers should have high index of suspicion for spontaneous hemothorax when evaluating new pleural effusion in patients receiving DOACs therapy. Drainage by small bore pigtail catheter might be as effective as larger chest tubes.

Outcomes in juvenile onset lupus: single center cohort from a developing country

Introduction

About 10–20% of systemic lupus erythematosus (SLE) patients have onset in childhood and have more severe organ involvement. Survival of juvenile SLE patients is improving worldwide. Long-term data of childhood onset SLE from developing countries is scarce.

Methods

Clinical and laboratory data at initial presentation and follow-up visits were retrieved from clinic files, hospital information system and personal interviews. Treatment received, complications, flares, outcomes and death were recorded. Survival was calculated using Kaplan–Meier survival curves and regression analysis was done for predictors of mortality.

Results

Children with SLE ( n = 273, 250 girls) had a median age at onset of 14 years and duration of illness prior to diagnosis at our hospital of 1 year. Fever and arthritis were the most common presenting manifestations. Renal disease was seen in 60.5% and central nervous system (CNS) disease in 29%. The median follow-up period in 248 patients was 3.5 years. Fourteen children died, and 10 of these had active disease at the time of death. The mean actuarial survival was 24.5 years and survival rates at 1, 5 and 10 years were 97.9%, 95% and 89% respectively. Fever, CNS disease, anti-dsDNA levels and serious infections predicted death on univariate and multivariate analysis. Infections were seen in 72 children (26.3%), and 38 of these infections were serious. One-third of the patients had damage on the last follow-up. Flares were seen in 120 children, the majority being major flares.

Conclusion

Outcomes of pediatric SLE in North Indian children are similar to those seen in developed countries. Infections pose a major challenge in these patients.

Mutant Variants of the Substrate-Binding Protein DppA from Escherichia coli Enhance Growth on Nonstandard γ-Glutamyl Amide-Containing Peptides

The import of nonnatural molecules is a recurring problem in fundamental and applied aspects of microbiology. The dipeptide permease (Dpp) of Escherichia coli is an ABC-type multicomponent transporter system located in the cytoplasmic membrane, which is capable of transporting a wide range of di- and tripeptides with structurally and chemically diverse amino acid side chains into the cell. Given this low degree of specificity, Dpp was previously used as an entry gate to deliver natural and nonnatural cargo molecules into the cell by attaching them to amino acid side chains of peptides, in particular, the γ-carboxyl group of glutamate residues. However, the binding affinity of the substrate-binding protein dipeptide permease A (DppA), which is responsible for the initial binding of peptides in the periplasmic space, is significantly higher for peptides consisting of standard amino acids than for peptides containing side-chain modifications. Here, we used adaptive laboratory evolution to identify strains that utilize dipeptides containing γ-substituted glutamate residues more efficiently and linked this phenotype to different mutations in DppA. In vitro characterization of these mutants by thermal denaturation midpoint shift assays and isothermal titration calorimetry revealed significantly higher binding affinities of these variants toward peptides containing γ-glutamyl amides, presumably resulting in improved uptake and therefore faster growth in media supplemented with these nonstandard peptides.IMPORTANCE Fundamental and synthetic biology frequently suffer from insufficient delivery of unnatural building blocks or substrates for metabolic pathways into bacterial cells. The use of peptide-based transport vectors represents an established strategy to enable the uptake of such molecules as a cargo. We expand the scope of peptide-based uptake and characterize in detail the obtained DppA mutant variants. Furthermore, we highlight the potential of adaptive laboratory evolution to identify beneficial insertion mutations that are unlikely to be identified with existing directed evolution strategies.

Secretome of Differentiated PC12 Cells Restores the Monocrotophos-Induced Damages in Human Mesenchymal Stem Cells and SHSY-5Y Cells: Role of Autophagy and Mitochondrial Dynamics

A perturbed cellular homeostasis is a key factor associated with xenobiotic exposure resulting in various ailments. The local cellular microenvironment enriched with secretory components aids in cell-cell communication that restores this homeostasis. Deciphering the underlying mechanism behind this restorative potential of secretome could serve as a possible solution to many health hazards. We, therefore, explored the protective efficacy of the secretome of differentiated PC12 cells with emphasis on induction of autophagy and mitochondrial biogenesis. Monocrotophos (MCP), a widely used neurotoxic organophosphate, was used as the test compound at sublethal concentration. The conditioned medium (CM) of differentiated PC12 cells comprising of their secretome restored the cell viability, oxidative stress and apoptotic cell death in MCP-challenged human mesenchymal stem cells and SHSY-5Y, a human neuroblastoma cell line. Delving further to identify the underlying mechanism of this restorative effect we observed a marked increase in the expression of autophagy markers LC3, Beclin-1, Atg5 and Atg7. Exposure to autophagy inhibitor, 3-methyladenine, led to a reduced expression of these markers with a concomitant increase in the expression of pro-apoptotic caspase-3. Besides that, the increased mitochondrial fission in MCP-exposed cells was balanced with increased fusion in the presence of CM facilitated by AMPK/SIRT1/PGC-1α signaling cascade. Mitochondrial dysfunctions are strongly associated with autophagy activation and as per our findings, cellular secretome too induces autophagy. Therefore, connecting these three potential apices can be a major breakthrough in repair and rescue of xenobiotic-damaged tissues and cells.

Synthesis and antiviral evaluation of cyclopentyl nucleoside phosphonates

The synthesis of both 2'-hydroxy-3'-deoxy and 2'-deoxy-3'-hydroxy cyclopentyl nucleoside phosphonates with the natural nucleobases adenine, thymine, cytosine and guanine from a single precursor has been performed. The guanine containing analogues showed antiviral activity. Especially the 3'-deoxy congener 23 was active, displaying an EC₅₀ of 5.35 μM against TK⁺ VZV strain and an EC₅₀ of 8.83 μM against TK^- VZV strain, besides lacking cytotoxicity. However, the application of phosphonodiamidate prodrug strategy did not lead to a boost in antiviral activity.

Effect of immobilisation on production of rapamycin by Streptomyces hygroscopicus

Numerous antibiotics as secondary metabolites have been isolated from microbes specifically Streptomyces sp. Rapamycin is one of these, which exhibits many roles as immunosuppressant, antifungal antibiotic, anti-tumour etc. Constant thrust has been put by many researchers to improve the production of rapamycin by Streptomyces hygroscopicus. Past research show that whole cell immobilisation is a useful strategy for antibiotic production with economical advantage. This study is another attempt in this direction which involves immobilisation of producer organism on various supports such as polyutherane foam, sintered beads, glass beads and foam peanuts. These support materials have been selected based on their availability and were pre-treated chemically to improve their adsorption capacity. Comparative profiles have been studied to identify the most suited support for the growth of Streptomyces sp. Variation of biomass immobilisation on various support materials with respect to time in batch culture was studied. Cell release study for the carriers was carried out in production medium to evaluate the performance of beads. Also, scanning electron microscopy (SEM) has been employed for visualisation and analysis of immobilised biomass and measurement of pore size. This study aims to determine a suitable support for immobilisation of Streptomyces hygroscopicus which could be used for rapamycin production in batch and continuous mode.

A novel heterozygous missense mutation in uromodulin gene in an Indian family with familial juvenile hyperuricemic nephropathy

Familial juvenile hyperuricemic nephropathy (FJHN), characterized by early-onset hyperuricemia, reduced fractional excretion of uric acid, and chronic renal failure is caused due to mutation in uromodulin (UMOD) gene. We identified a novel mutation in a family with multiple members affected with FJHN. Ten coding exons of UMOD gene in three family members with clinical and biochemical features of FJHN and one unaffected family member were sequenced, and sequence variants were analyzed for the pathogenicity by bioinformatics studies. A heterozygous novel missense mutation (c. 949 T >G) in exon 5 leading to the replacement of cysteine by glycine at position 317 was identified in all three affected family members. This mutation has not been reported earlier in Human Gene Mutation Database, Human Genome Variation, Clinvar, and 1000 Genome. The mutation lies in the cysteine-rich 2 domain of the protein, and the affected residue is evolutionary conserved in other species. To our knowledge, this is the first report of the identification of UMOD mutation in an Indian family.

Incorporation of Amino Acids with Long-Chain Terminal Olefins into Proteins

The increasing need for site-specific protein decorations that mimic natural posttranslational modifications requires access to a variety of noncanonical amino acids with moieties enabling bioorthogonal conjugation chemistry. Here we present the incorporation of long-chain olefinic amino acids into model proteins with rational variants of pyrrolysyl-tRNA synthetase (PylRS). Nε-heptenoyl lysine was incorporated for the first time using the known promiscuous variant PylRS(Y306A/Y384F), and Nε-pentenoyl lysine was incorporated in significant yields with the novel variant PylRS(C348A/Y384F). This is the only example of rational modification at position C348 to enlarge the enzyme's binding pocket. Furthermore, we demonstrate the feasibility of our chosen amino acids in the thiol-ene conjugation reaction with a thiolated polysaccharide.