Infusible platelet membrane microvesicles: a potential transfusion substitute for platelets

BACKGROUND: Several substitutes for intact, viable platelets have been used for transfusion, both to people and in animal models, with varied success. Infusible platelet membrane (IPM) is prepared from human platelets. IPM retains the glycoprotein (GP)lb receptor and has platelet factor 3 activity (procoagulant activity). However, factor V, serotonin, a cytoplasmic marker enzyme (purine nucleotide phosphorylase), GPIIb/IIIa complex, and HLA class I and II antigens are all absent in IPM. STUDY DESIGN AND METHODS: IPM is prepared from outdated platelets. The platelets were disrupted by freezing and thawing; they were washed and heated to inactivate possible viral contaminants, and then the sonicated membrane microvesicle fraction was separated and lyophilized. The hemostatic activity of IPM was measured by its ability to reduce the prolonged bleeding time in thrombocytopenic rabbits. RESULTS: Administration of IPM at a dose of 2 mg per kg results in a substantial reduction in the bleeding time. In a series of 23 experiments, a median preinjection bleeding time of 15 minutes was reduced to 6 minutes within 4 hours after IPM administration. Administration of IPM did show a mild enhancement in the thrombogenicity index, as measured in the Wessler rabbit model. This enhancement is, however, not significant, as a thrombogenicity index value of up to 0.6 is clinically acceptable. CONCLUSION: IPM may have clinical potential as a substitute for platelets in the treatment of bleeding due to thrombocytopenia.     

Functional MRI of sentence comprehension in children with dyslexia: beyond word recognition

Sentence comprehension (SC) studies in typical and impaired readers suggest that reading for meaning involves more extensive brain activation than reading isolated words. Thus far, no reading disability/dyslexia (RD) studies have directly controlled for the word recognition (WR) components of SC tasks, which is central for understanding comprehension processes beyond WR. This experiment compared SC to WR in 29, 9-14 year olds (15 typical and 14 impaired readers). The SC-WR contrast for each group showed activation in left inferior frontal and extrastriate regions, but the RD group showed significantly more activation than Controls in areas associated with linguistic processing (left middle/superior temporal gyri), and attention and response selection (bilateral insula, right cingulate gyrus, right superior frontal gyrus, and right parietal lobe). Further analyses revealed this overactivation was driven by the RD group's response to incongruous sentences. Correlations with out-of-scanner measures showed that better word- and text-level reading fluency was associated with greater left occipitotemporal activation, whereas worse performance on WR, fluency, and comprehension (reading and oral) were associated with greater right hemisphere activation in a variety of areas, including supramarginal and superior temporal gyri. Results provide initial foundations for understanding the neurobiological correlates of higher-level processes associated with reading comprehension.     

Adjuvant therapy for locally advanced renal cell cancer: A systematic review with meta-analysis

Background  

Many adjuvant trials have been undertaken in an attempt to reduce the risk of recurrence among patients who undergo surgical resection for locally advanced renal cancer. However, no clear benefit has been identified to date. This systematic review was conducted to examine the exact role of adjuvant therapy in renal cancer setting.     

Effects of L-histidine depletion and L-tyrosine/L-phenylalanine depletion on sensory and motor processes in healthy volunteers

Background and purpose:

Animal studies show that histamine plays a role in cognitive functioning and that histamine H₃-receptor antagonists, which increase histaminergic function through presynaptic receptors, improve cognitive performance in models of clinical cognitive deficits. In order to test such new drugs in humans, a model for cognitive impairments induced by low histaminergic functions would be useful. Studies with histamine H₁-receptor antagonists have shown limitations as a model. Here we evaluated whether depletion of L-histidine, the precursor of histamine, was effective in altering measures associated with histamine in humans and the behavioural and electrophysiological (event-related-potentials) effects.

Experimental approach:

Seventeen healthy volunteers completed a three-way, double-blind, crossover study with L-histidine depletion, L-tyrosine/L-phenylalanine depletion (active control) and placebo as treatments. Interactions with task manipulations in a choice reaction time task were studied. Task demands were increased using visual stimulus degradation and increased response complexity. In addition, subjective and objective measures of sedation and critical tracking task performance were assessed.

Key results:

Measures of sedation and critical tracking task performance were not affected by treatment. L-histidine depletion was effective and enlarged the effect of response complexity as measured with the response-locked lateralized readiness potential onset latency.

Conclusions and implications:

L-histidine depletion affected response- but not stimulus-related processes, in contrast to the effects of H₁-receptor antagonists which were previously found to affect primarily stimulus-related processes. L-histidine depletion is promising as a model for histamine-based cognitive impairment. However, these effects need to be confirmed by further studies.     

To Study the Flow Property of Seven Commercially Available Zinc Oxide Eugenol Impression Material at Various Time Intervals After Mixing

Aims and objective of the study was to evaluate the flow property of seven commercially available zinc oxide eugenol impression materials at various time intervals, after mixing 49 samples (seven groups) were fabricated for flow property of the material. The sample were fabricated as equal length of base and accelerator paste of the test materials was taken on the glass slab and mixed with a rigid stainless steel spatula as per manufacturers recommendation till the homogenous mix was obtained. The mix material was loaded in glass syringe and 0.5 ml material was injected on a cellophane sheet placed on marked glass plate. A cellophane sheet and glass plate 70 and 500 g weight was carefully placed on freshly dispensed zinc oxide eugenol impression paste sequentially. The diameter of the mix was noted after 30 s and 1 min of load application and also after the final set of material. The diameter gives the flow of material. The samples were stored at the room temperature. The data of the flow property was analyzed with analysis of variance, Post hoc test and t test. The flow of the zinc oxide eugenol impression paste after 30 s, 1 min and final set of load application for Group A to Group G was noted. Maximum flow was seen for Group G zinc oxide eugenol impression material followed by Group F, D, E, B, C and A in descending order respectively after 30 s, where as the flow property changed after 1 min in the sequence of maximum for Group G followed by Group E, D, B, A, C, and F. Lastly after final set of the impression material the flow maximum for Group G followed by Group E, D, C, F, A and B in descending order. Based on statistical analysis of the results and within in the limitations of this in-vitro study, the following conclusions were drawn that; the flow of zinc oxide eugenol impression material after 30 s, 1 min and that after the final set was maximum for P.S.P. (Group G) and the flow for PYREX (Group A) was minimum.     

Complete nucleotide sequence of a begomovirus associated with satellites molecules infecting a new host Tagetes patula in India

In the year 2012 leaf curl disease was observed on Marigold (Tagetes patula) in Lakshmangrh, Sikar province of India. Affected plants were severely stunted with apical leaf curl and crinkled leaves, symptoms typical of begomovirus infection. This is the first report of complete nucleotide sequence of a begomovirus associated with satellites molecules infecting a new host Tagetes patula in India.     

Clinical Performance Characteristics of the Swift Normalase Amplicon Panel for Sensitive Recovery of Severe Acute Respiratory Syndrome Coronavirus 2 Genomes

Amplicon-based sequencing methods are central in characterizing the diversity, transmission, and evolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), but need to be rigorously assessed for clinical utility. Herein, we validated the Swift Biosciences'' SARS-CoV-2 Swift Normalase Amplicon Panels using remnant clinical specimens. High-quality genomes meeting our established library and sequence quality criteria were recovered from positive specimens, with 95% limit of detection of 40.08 SARS-CoV-2 copies/PCR. Breadth of genome recovery was evaluated across a range of C_T values (11.3 to 36.7; median, 21.6). Of 428 positive samples, 413 (96.5%) generated genomes with <10% unknown bases, with a mean genome coverage of 13,545× ± SD 8382×. No genomes were recovered from PCR-negative specimens (n = 30) or from specimens positive for non–SARS-CoV-2 respiratory viruses (n = 20). Compared with whole-genome shotgun metagenomic sequencing (n = 14) or Sanger sequencing for the spike gene (n = 11), pairwise identity between consensus sequences was 100% in all cases, with highly concordant allele frequencies (R² = 0.99) between Swift and shotgun libraries. When samples from different clades were mixed at varying ratios, expected variants were detected even in 1:99 mixtures. When deployed as a clinical test, 268 tests were performed in the first 23 weeks, with a median turnaround time of 11 days, ordered primarily for outbreak investigations and infection control.

Since the deposition of the first severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) whole genome sequence (NC_045512.1) in January 2020, >4 million SARS-CoV-2 genomes have been deposited to public data repositories, far exceeding any other human pathogen.^1,2 Such a feat has been made possible because of advances in next-generation sequencing (NGS) technologies that enable near real-time genomic surveillance.3, 4, 5, 6, 7, 8, 9 Viral whole-genome sequencing (WGS) of laboratory-confirmed SARS-CoV-2 isolates is frequently used in outbreak investigations, deployment of public health interventions, development of vaccines and therapeutics, and evaluation of vaccine and antiviral effectiveness against emerging variants.4, 5, 6^,10, 11, 12, 13, 14, 15 Specific SARS-CoV-2 variants have been associated with higher viral loads, lower vaccine effectiveness, and worse outcomes, such as mortality.16, 17, 18, 19, 20, 21, 22, 23 Notably, B.1.1.7 has been associated with increased disease severity, prolonged hospitalization, and higher mortality risk.^16,18,19,21, 22, 23, 24 In addition, recent studies have shown poorer outcomes for patients infected with variants B.1.351 and P.1.^23,25 In a clinical setting, identification of specific viral mutations can aid in the selection of monoclonal therapies,26, 27, 28, 29 and viral sequencing can be used to monitor the accumulation of mutations during long-term viral replication in immunocompromised individuals.³⁰ As treatment regimens expand, validated WGS assays are needed not only for genomic surveillance but also for high-quality, clinically actionable data with rapid turnaround times.Multiplexed amplicon sequencing methods have proven to be faster, more sensitive, and more cost-effective than shotgun and capture-based approaches, enabling genome recovery across a wide range of viral loads.^31,32 We previously tested one such panel from Swift Biosciences and demonstrated genome recovery up to a C_T of 36 across a broad range of isolates.³³ Designed against the SARS-CoV-2 Wuhan–Hu-1 complete genome (https://www.ncbi.nlm.nih.gov/nuccore, accession number {type:entrez-nucleotide,attrs:{text:NC_045512.2,term_id:1798174254,term_text:NC_045512.2}}NC_045512.2, last accessed July 12, 2022), the Swift Normalase Amplicon Panel (SNAP) primer set amplifies 345 amplicons ranging from 116 to 255 bp (average, 150 bp) in a single tube to cover the approximately 30-kb SARS-CoV-2 genome. This assay can generate libraries in <3 hours using an input concentration of only 10 to 100+ viral copies for single-strand cDNA or double-strand cDNA synthesis. This can be followed by either manual normalization or Swift Biosciences'' proprietary enzymatic normalization of multiplexed libraries for equimolar pools.For clinical use, sequencing assays need to be rigorously validated, documented, and performed in Clinical Laboratory Improvement Amendments–accredited laboratories. However, no specific guidelines currently exist for the development and validation of WGS assays for SARS-CoV-2. We validated the Swift Biosciences'' one-tube SARS-CoV-2 SNAP Version 2.0—the first clinical validation of an NGS-based assay for WGS of SARS-CoV-2 to our knowledge—according to US Food and Drug Administration’s “Considerations for Design, Development, and Analytical Validation of Next Generation Sequencing-Based in Vitro Diagnostics Intended to Aid in the Diagnosis of Suspected Germline Diseases” (https://www.fda.gov/media/99208/download, last accessed January 4, 2021) and US Food and Drug Administration''s “Submitting Next Generation Sequencing Data to the Division of Antiviral Products Guidance for Industry” Technical Specifications Document (https://www.fda.gov/regulatory-information/search-fda-guidance-documents/submitting-next-generation-sequencing-data-division-antiviral-products-guidance-industry-technical, last accessed August 19, 2021). Using clinical specimens, the analytical sensitivity, analytical specificity, limit of detection, accuracy, and precision (reproducibility and repeatability) of the assay were evaluated, establishing acceptance criteria for sequencing libraries and output genomes. This assay is now available as a clinically orderable test, with results returned to physicians to aid in disease management and treatment. It has been used in multiple vaccine trials, research studies, validation of other NGS-based assays, and sequencing SARS-CoV-2 for public health surveillance and outbreak investigation.^4,6,10,34, 35, 36, 37, 38