A Rare Case of Pseudomonas putida Bacteremia in a Patient with Cirrhosis of Liver.

Pseudomonas putida (P. putida) is a rare pathogen that primarily causes nosocomial infection. It is usually seen in immune dysfunction or immunocompromised patients and patients with invasive medical devices. Here, we present a rare case of P. putida bacteremia in a patient with cirrhosis of the liver.

Multimodal Neurologic Monitoring in Patients Undergoing Extracorporeal Membrane Oxygenation.

Introduction Extracorporeal membrane oxygenation (ECMO) is associated with a high rate of neurologic complications. Multimodal neurologic monitoring (MNM) has the potential for early detection and intervention. We examined the safety and feasibility of noninvasive MNM during ECMO. We hypothesized that survivors and non-survivors would have meaningful differences in transcranial Doppler (TCD) sonography and electroencephalographic (EEG) characteristics, which we aimed to identify. We also investigated adverse neurologic events and attempted to identify differences in EEG and TCD characteristics among patients based on the type of ECMO and the occurrence of these events. Material and methods We performed an observational study on all patients undergoing ECMO at Baylor St. Luke's Medical Center's critical care unit in Houston, Texas, United States, from January 2017 to February 2019. All patients underwent a noninvasive MNM protocol. Results NM was completed in 75% of patients; all patients received at least one component of the monitoring protocol. No adverse events were noted, showing the feasibility and safety of the protocol. The 60.4% of patients who did not survive tended to be older, had lower ejection fractions, and had lower median right middle cerebral artery (MCA) pulsatility and resistivity indexes. Patients undergoing venoarterial (VA)-ECMO had lower median left and right MCA velocities and lower right Lindegaard ratios than patients who underwent venovenous-ECMO. In VA-ECMO patients, EEG less often showed sleep architecture, while other findings were similar between groups. Adverse neurologic events occurred in 24.7% of patients, all undergoing VA-ECMO. Acute ischemic stroke occurred in 22% of patients, intraparenchymal hemorrhage in 4.9%, hypoxic-ischemic encephalopathy in 3.7%, subarachnoid hemorrhage in 2.5%, and subdural hematoma in 1.2%. Conclusion Our results suggest that MNM is safe and feasible for patients undergoing ECMO. Certain EEG and TCD findings could aid in the early detection of neurologic deterioration. MNM may not just be used in monitoring patients undergoing ECMO but also in prognostication and aiding clinical decision-making.

Scrub typhus-related hepatotoxicity: The Indian scenario.

In Scrunb Typhus, hepatotoxicity is an important, yet understudied, manifestation. We reviewed studies on scrub typhus, published in the last five years (2014-2019), which evaluated its clinico-epidemiological factors in India, and concentrated on its hepatic involvement. Nine studies were found, and no Indian study exclusively evaluated hepatic dysfunction. Thus, comments from a few international studies were also included. We conclude that liver dysfunction in the form of elevated serum transaminase levels is a common manifestation of scrub typhus, which may herald progress to fulminant hepatic failure.

BLM helicase is activated in BCR/ABL leukemia cells to modulate responses to cisplatin.

Bloom protein (BLM) is a 3'-5' helicase, mutated in Bloom syndrome, which plays an important role in response to DNA double-strand breaks and stalled replication forks. Here, we show that BCR/ABL tyrosine kinase, which also modulates DNA repair capacity, is associated with elevated expression of BLM. Downregulation of BLM by antisense cDNA or dominant-negative mutant inhibits homologous recombination repair (HRR) and increases sensitivity to cisplatin in BCR/ABL-positive cells. Bone marrow cells from mice heterozygous for BLM mutation, BLM(Cin/+), transfected with BCR/ABL display increased sensitivity to cisplatin compared to those obtained from the wild-type littermates. BCR/ABL promotes interactions of BLM with RAD51, while simultaneous overexpression of BLM and RAD51 in normal cells increases drug resistance. These data suggest that BLM collaborates with RAD51 to facilitate HRR and promotes the resistance of BCR/ABL-positive leukemia cells to DNA-damaging agents.

HIV-1 Tat increases cell survival in response to cisplatin by stimulating Rad51 gene expression.

Tat is an early regulatory protein of human immunodeficiency virus type 1, which plays a central role in the pathogenesis of AIDS by stimulating transcription of the viral genome and impairing several important cellular pathways during the progression of the disease. Here, we investigated the effect of Tat on cell response to DNA damage. Our results indicate that Tat production causes a noticeable increase in the survival rate of PC12 cells upon their treatment with genotoxic agents. Single-cell gel electrophoresis studies revealed reduced DNA breakage in PC12-Tat cells upon cisplatin treatment relative to the control cells. Furthermore, cytogenetic data exhibited less chromosomal damage in Tat-producing cells after recovery from cisplatin treatment, corroborating electrophoretic data. Examination of several proteins involved in the control of DNA repair showed elevated levels of Rad51, a key regulator of homologous recombination in cells expressing Tat. On the other hand, the level of Ku70, one of the components of the nonhomologous end-joining repair pathway, was slightly decreased in cells expressing Tat. Using a fluorescence-based assay, we demonstrated that repair of DNA double-strand breaks via homologous recombination is increased in Tat-producing cells. The results from in vitro nonhomologous end-joining assay revealed a reduced ability of protein extract from PC12-Tat cells compared to PC12 cells in rejoining linearized DNA. These observations ascribe a new role for Tat in host genomic integrity, perhaps by affecting the expression of genes involved in DNA repair.

Role of JC virus agnoprotein in DNA repair.

The late region of human neurotropic JC virus encodes a small 71-amino-acid agnoprotein that is also found in the polyomaviruses simian virus 40 and BK virus. Several functions of agnoprotein have been identified, including roles in regulating viral transcription and virion maturation. Earlier studies showed that agnoprotein expressed alone induced p21/WAF-1 expression and caused cells to accumulate in the G(2)/M stage of the cell cycle. Here we report that agnoprotein expression sensitized cells to the cytotoxic effects of the DNA-damaging agent cisplatin. Agnoprotein reduced the viability of cisplatin-treated cells and increased chromosome fragmentation and micronucleus formation. Whereas cisplatin-treated control cells accumulated in S phase, cells expressing agnoprotein did not, instead becoming aneuploid. Agnoprotein expression correlated with impaired double-strand-break repair activity in cellular extracts and reduced expression of the Ku70 and Ku80 DNA repair proteins. After agnoprotein expression, much of the Ku70 protein was located in the perinuclear space, where agnoprotein was also found. Results from binding studies showed an interaction of agnoprotein with Ku70 which was mediated by the N terminus. The ability of agnoprotein to inhibit double-strand break repair activity when it was added to cellular extracts was also mediated by the N terminus. We conclude that agnoprotein inhibits DNA repair after DNA damage and interferes with DNA damage-induced cell cycle regulation. Since Ku70 is a subunit of the DNA-dependent protein kinase that is responsible both for double-strand break repair and for signaling damage-induced cell cycle arrest, the modulation of Ku70 and/or Ku80 by agnoprotein may represent an important event in the polyomavirus life cycle and in cell transformation.

Cell-type-specific gene delivery into neuronal cells in vitro and in vivo.

The avian retroviruses reticuloendotheliosis virus strain A (REV-A) and spleen necrosis virus (SNV) are not naturally infectious in human cells. However, REV-A-derived viral vectors efficiently infect human cells when they are pseudotyped with envelope proteins displaying targeting ligands specific for human cell-surface receptors. Here we report that vectors containing the gag region of REV-A and pol of SNV can be pseudotyped with the envelope protein of vesicular stomatitis virus (VSV) and the glycoproteins of different rabies virus (RV) strains. Vectors pseudotyped with the envelope protein of the highly neurotropic RV strain CVS-N2c facilitated cell type-specific gene delivery into mouse and human neurons, but did not infect other human cell types. Moreover, when such vector particles were injected into the brain of newborn mice, only neuronal cells were infected in vivo. Cell-type-specific gene delivery into neurons may present quite specific gene therapy approaches for many degenerative diseases of the brain.