Biology subjects

Gaur, P.

Publications and source records attributed to Gaur, P..

23 records · Page 2Linked to original sources

bioRxiv2020

Protein stability and functional activity during nebulization: A comparative study of three nebulizer!

Delivery of therapeutics protein to the lung offers effective treatments of lungs disease. Efficacy of delivered therapeutics molecules depends on integrity and stability of protein during nebulization. In this study, we compared three nebulizers: compressed air nebulizer (CAN), ultrasonic nebulizer (USN) and mesh nebulizer (MAN) to deliver aerosol dose, stability and functional activity of a model protein lysozyme. Lysozyme/BSA delivered dose assessed by indirect and direct method. It was shown CAN deliver 0.142{+/-}0.027 to 0.632{+/-} 0.09 ml of protein, USN deliver 0.511{+/-}0.119 to 1.688{+/-}0.173 ml and MAN deliver 0.238{+/-}0.006 to 0.731{+/-}0.013 ml of protein in the same time. Integrity of nebulized proteins were assessed by gel electrophoresis and circular diochorism. It was found integrity of lysozyme compromised in all three nebulizer maximum in CAN and minimum with MAN. The functional activity of protein was assessed after nebulization by turbidometry assay. The functional activity was compromised by all three nebulizer upto some extent. In conclusion, nebulization compromise protein stability: this impact depend on nebulization techniques as well as nature of protein. The CAN deliver protein more precisely in small amount in comparison to the other nebulizer. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=122 SRC="FIGDIR/small/085720v1_ufig1.gif" ALT="Figure 1"> View larger version (30K): org.highwire.dtl.DTLVardef@5b230forg.highwire.dtl.DTLVardef@15ac79corg.highwire.dtl.DTLVardef@e7130forg.highwire.dtl.DTLVardef@94684e_HPS_FORMAT_FIGEXP M_FIG Graphical Abstract C_FIG

bioengineering↗

bioRxiv2019

Histologic safety of transcranial focused ultrasound neuromodulation and magnetic resonance acoustic radiation force imaging in rhesus macaques and sheep

BackgroundNeuromodulation by transcranial focused ultrasound (FUS) offers the potential to non-invasively treat specific brain regions, with treatment location verified by magnetic resonance acoustic radiation force imaging (MR-ARFI).\n\nObjectiveTo investigate the safety of these methods prior to widespread clinical use, we report histologic findings in two large animal models following FUS neuromodulation and MR-ARFI.\n\nMethodsTwo rhesus macaques and thirteen Dorset sheep were studied. FUS neuromodulation was targeted to the primary visual cortex in rhesus macaques and to subcortical locations, verified by MR-ARFI, in eleven sheep. Both rhesus macaques and five sheep received a single FUS session, whereas six sheep received repeated sessions three to six days apart. The remaining two control sheep did not receive ultrasound but otherwise underwent the same anesthetic and MRI procedures as the eleven experimental sheep. Hematoxylin and eosin-stained sections of brain tissue (harvested zero to eleven days following FUS) were evaluated for tissue damage at FUS and control locations as well as tissue within the path of the FUS beam. TUNEL staining was used to evaluate for the presence of apoptosis in sheep receiving high dose FUS.\n\nResultsNo FUS-related pre-mortem histologic findings were observed in the rhesus macaques or in any of the examined sheep. Extravascular red blood cells (RBCs) were present within the meninges of all sheep, regardless of treatment group. Similarly, small aggregates of perivascular RBCs were rarely noted in non-target regions of neural parenchyma of FUS-treated (8/11) and untreated (2/2) sheep. However, no concurrent histologic abnormalities were observed, consistent with RBC extravasation occurring as post-mortem artifact following brain extraction. Sheep within the high dose FUS group were TUNEL-negative at the targeted site of FUS.\n\nConclusionsThe absence of FUS-related histologic findings suggests that the neuromodulation and MR-ARFI protocols evaluated do not cause tissue damage.

bioengineering↗

bioRxiv2018

Early detection of impending cryostorage tank failure using a weight-based monitoring system

ObjectTo study the ability of custom-built, web-enabled scales to monitor liquid nitrogen (LN2) levels in cryostorage dewars.\n\nDesignLaboratory study\n\nSettingA large academic fertility center in New York City.\n\nInterventionsCryostorage dewars were placed on top of the custom-engineered scales with continuous real-time monitoring, and weight and temperature data were recorded in the setting of slow, medium, and fast rate-loss of LN2 designed to mimic models of tank failures.\n\nMain Outcome MeasuresWeights were continuously monitored and recorded, with a calculated alarm trigger set at 10% weight loss. Temperature within the tanks was simultaneously monitored with probes placed near the top of the tanks, with calculated alarms using a -185 {degrees}C as the threshold. For the \"slow rate-loss\" simulations, tanks were left intact and closed in usual operating conditions, and LN2 was allowed to evaporate at the normal rate. For the \"medium rate-loss\" simulation, the foam core of the tank neck was removed and the insulating vacuum was eliminated by making a 1/16 inch hole in the outer tank wall. For the \"fast rate-loss\" simulation, a 1/16\" hole was made through the outer tank wall and LN2 was released at a rate of 0.15 L/second. All simulations were performed in duplicate.\n\nResultsWith an intact and normally functioning tank, a 10% loss in LN2 occurred in 4.2-4.9 days. Warming to -185 {degrees}C occurred in 37.8 - 43.7 days, over 30 days after the weight-based alarm was triggered. Full evaporation of LN2required 36.8 days. For the medium rate-loss simulation, a 10% loss in LN2 occurred in 0.8 h. Warming to -185 {degrees}C occurred in 3.7 - 4.8 hours, approximately 3 hours after the weight-based alarm was triggered. For the fast rate-loss simulation, a 10% weight loss occurred within 15 seconds and tanks were completely depleted in under 3 minutes. Tank temperatures began to rise immediately and at a relatively constant rate of 43.9 {degrees}C/hour and 51.6 {degrees}C/hour. Temperature alarms would have sounded within 0.37 and 0.06 hours after the breech.\n\nConclusionsThis study demonstrates that a weight-based, automated alarm system can detect tank failures prior to a temperature-based alarm system, in some cases over a month in advance. In combination with existing safety mechanisms such as temperature probes, a weight-based monitoring system could serve as a redundant safety mechanism for added protection of cryopreserved reproductive tissues.

developmental biology↗

bioRxiv2018

Rapid preimplantation genetic screening (PGS) using a handheld, nanopore-based, DNA sequencer

ObjectiveTo determine if a handheld, nanopore-based DNA sequencer can be used for rapid preimplantation genetic screening (PGS).\n\nDesignRetrospective study.\n\nSettingAcademic medical center.\n\nPatient(s)Amplified genomic DNA from euploid and aneuploid trophectoderm biopsy samples (n=9) that was also tested using traditional next generation sequencing (NGS).\n\nIntervention(s)Short-read DNA library preparation and nanopore-based sequencing using a hand-held MinION sequencer.\n\nMain outcome measure(s)Comparison of cytogenetic testing result from NGS and nanopore-based sequencing and the time required for library preparation and sequencing.\n\nResult(s)Multiplexed short-read DNA library preparation was completed in 45 minutes. Sequencing times varied from 1 to 2 hours. These times compare favorably with NGS library preparation (>3.5 hours) and sequencing (>12 hours) times. Whole-chromosome aneuploidy screening results obtained from nanopore-based sequencing were identical to those obtained using NGS.\n\nConclusion(s)Methods for PGS of embryos have evolved from FISH to microarrays and most recently to NGS. Here we report the first application of nanopore-based sequencing for PGS on trophecoderm biopsy samples using a rapid multiplex short-read nanopore sequencing library preparation. Aneuploidy screening could be performed on 5 samples in one nanopore flowcell with 1 to 2 hour sequencing times. Overall, nanopore sequencing is a promising tool to perform rapid PGS assay onsite with a rapid turnover time, enabling same day testing and embryo transfer thus obviating the need for complex, large and expensive DNA sequencers or frozen embryos.

genetics↗

bioRxiv2017

The immunomodulatory CEA cell adhesion molecule 6 (CEACAM6/CD66c) is a candidate receptor for the influenza A virus

To establish a productive infection in host cells, viruses often use one or multiple host membrane glycoprotein as their receptors. For Influenza A virus (IAV) such a glycoprotein receptor has not been described, to date. Here we show that IAV is using the host membrane glycoprotein CD66c as a receptor for entry into human epithelial lung cells. Neuraminidase (NA), a viral spike protein binds to CD66c on the cell surface during IAV entry into the host cells. Lung cells overexpressing CD66c showed an increase in virus binding and subsequent entry into the cell. Upon comparison, CD66c demonstrated higher binding capacity than other membrane glycoproteins (EGFR and DC-SIGN) reported earlier to facilitate IAV entry into host cells. siRNA mediated knockdown of CD66c from lung cells inhibited virus binding on cell surface and entry into cells. Blocking CD66c by antibody on the cell surface resulted in decreased virus entry. We found CD66c is a specific glycoprotein receptor for influenza A virus that did not affect entry of non-IAV RNA virus (Hepatitis C virus). Finally, IAV pre-incubated with recombinant CD66c protein when administered intranasally in mice showed decreased cytopathic effects in mice lungs. This publication is the first to report CD66c (CEACAM6) as a glycoprotein receptor for Influenza A virus.\n\nSignificance StatementCells are enclosed by a semipermeable membrane that allows selective exchange of biomolecules between cells and their surroundings. A set of specialized proteins in this semipermeable membrane, work like gatekeepers to the cell and regulate entry of these biomolecules. One class of such surface proteins is termed as receptors. Viruses bind to one or more of these receptors and manipulate gatekeepers for their own successful entry into host-cells. A membrane protein that influenza A virus (Flu virus) uses for entry into the cells was not discovered till date. This study reports for the first time, a receptor for influenza A virus, that was sought after by researchers for decades. The viral receptor is a promising target that can be used to inhibit virus entry into host cells.

microbiology↗