Analytical assay validation for acute myeloid leukemia measurable residual disease assessment by multiparametric flow cytometry

Background: Measurable residual disease (MRD) assessed by multiparametric flow cytometry (MFC) has gained importance in clinical decision-making for acute myeloid leukemia (AML) patients. However, complying with the recent In Vitro Diagnostic Regulations (IVDR) in Europe and Food and Drug Administration (FDA) guidance in the United States requires rigorous validation prior to their use in investigational clinical trials and diagnostics. Validating AML MRD-MFC assays poses challenges due to the unique underlying disease biology and paucity of patient specimens. In this study, we describe an experimental framework for validation that meets regulatory expectations. Methods: Our validation efforts focused on evaluating assay accuracy, analytical specificity, analytical and functional sensitivity (limit of blank (LoB), detection (LLoD) and quantitation (LLoQ)), precision, linearity, sample/reagent stability and establishing the assay background frequencies. Results: Correlation between different MFC methods was highly significant (r = 0.99 for %blasts and r = 0.93 for %LAIPs). The analysis of LAIP specificity accurately discriminated from negative control cells. The assay demonstrated a LoB of 0.03, LLoD of 0.04, and LLoQ of 0.1%. Precision experiments yielded highly reproducible results (Coefficient of Variation &lt;20%). Stability experiments demonstrated reliable measurement of samples up to 96 h from collection. Furthermore, the reference range of LAIP frequencies in non-AML patients was below 0.1%, ranging from 0.0% to 0.04%.Conclusion: In this manuscript, we present the validation of an AML MFC-MRD assay using BM/PB patient specimens, adhering to best practices. Our approach is expected to assist other laboratories in expediting their validation activities to fulfill recent health authority guidelines.</p

Genetic Diversity Patterns and Heterosis Prediction Based on SSRs and SNPs in Hybrid Parents of Pearl Millet

The present investigation was performed to assess genetic divergence and heterosis prediction in hybrid parents of pearl millet [Pennisetum glaucum (L.) R Br.] using simple sequence repeat (SSR) and single nucleotide polymorphism (SNP) markers. Using 56 SSR loci, 412 alleles were detected in 147 lines with an average of 7.36 alleles per locus, and 75,007 SNP loci were detected in 117 lines. Both SSR- and SNP-based clustering and structure analysis partitioned all maintainer (B) and restorer (R) lines into two clear-cut separate groups, indicating the existence of two diverse gene pools, each representing the seed and restorer parents in pearl millet. Results of analysis of molecular variance and principal coordinate analysis also showed significant diversity between B and R lines. The correlation between parental genetic distances estimated based on SSRs and SNPs was high and significant (r = 0.58, p < .01). Similar clustering pattern of hybrid parents was observed with both marker systems, although the cost of genotyping was 41% less with SNPs than with SSRs, and the ratio of loci detected with SNPs was much higher (1:364 SSR/SNP), hence the use of SNPs is indicated over SSRs for germplasm characterization. A set of 136 hybrids (including all B × B, R × R, and B × R crosses) generated crossing 17 hybrid parents (nine B lines and eight R lines) in half diallel (without reciprocal) fashion, and evaluation at two locations revealed that the correlation between genetic distance and better parent heterosis for grain yield was moderate, positive, and significant (with SSR, 0.33, p < .01; with SNP, 0.35, p < .01), hence both SSRs and SNPs were found comparable in results for heterosis prediction

Central pancreatectomy without anastomosis

<p>Abstract</p> <p>Background</p> <p>Central pancreatectomy has a unique application for lesions in the neck of the pancreas. It preserves the distal pancreas and its endocrine functions. It also preserves the spleen.</p> <p>Methods</p> <p>This is a retrospective review of 10 patients who underwent central pancreatectomy without pancreatico-enteric anastomosis between October 2005 and May 2009. The surgical indications, operative outcomes, and pathologic findings were analyzed.</p> <p>Results</p> <p>All 10 lesions were in the neck of the pancreas and included: 2 branch intraductal papillary mucinous neoplasms (IPMNs), a mucinous cyst, a lymphoid cyst, 5 neuroendocrine tumors, and a clear cell adenoma.</p> <p>Conclusion</p> <p>Central pancreatectomy without pancreatico-enteric anastomosis for lesions in the neck and proximal pancreas is a safe and effective procedure. Morbidity is low because there is no anastomosis. Long term endocrine and exocrine function has been maintained.</p

A critical review of experimental results on low temperature charge transport in carbon nanotubes based composites

Owing to their low density, high aspect ratio and excellent charge transport properties, Carbon nanotubes (CNTs) are proven to be one of the best reinforcing materials in the fabrication of composite materials. CNTs dispersed in a non-conducting matrix is an interesting system for condensed matter physicists and materials scientists; CNT based composites offer an opportunity to physicists to design different experiments for fundamental studies while these composites are suitable for several technological applications that are of interest to materials scientists. In this review article, we summarize interesting experimental results on low temperature charge transport properties of composites based on multi-wall carbon nanotubes (MWCNTs) that have been reported in the past decade. In particular, we critically review different conduction mechanisms that have been identified through detailed investigations of charge transport characteristics as functions of MWCNT loading in the composites, temperature, and magnetic field. Keywords: Carbon nanotubes, Percolation threshold, Variable range hopping and fluctuation induced tunneling conductio

Neoadjuvant Pembrolizumab and High-Dose IFNα-2b in Resectable Regionally Advanced Melanoma

PurposeNeoadjuvant immunotherapy may improve the clinical outcome of regionally advanced operable melanoma and allows for rapid clinical and pathologic assessment of response. We examined neoadjuvant pembrolizumab and high-dose IFNα-2b (HDI) therapy in patients with resectable advanced melanoma.Patients and methodsPatients with resectable stage III/IV melanoma were treated with concurrent pembrolizumab 200 mg i.v. every 3 weeks and HDI 20 MU/m2/day i.v., 5 days per week for 4 weeks, then 10 MU/m2/day subcutaneously 3 days per week for 2 weeks. Definitive surgery followed, as did adjuvant combination immunotherapy, completing a year of treatment. Primary endpoint was safety of the combination. Secondary endpoints included overall response rate (ORR), pathologic complete response (pCR), recurrence-free survival (RFS), and overall survival (OS). Blood samples for correlative studies were collected throughout. Tumor tissue was assessed by IHC and flow cytometry at baseline and at surgery.ResultsA total of 31 patients were enrolled, and 30 were evaluable. At data cutoff (October 2, 2019), median follow-up for OS was 37.87 months (range, 33.2-43.47). Median OS and RFS were not reached. Radiographic ORR was 73.3% [95% confidence interval (CI): 55.5-85.8], with a 43% (95% CI: 27.3-60.1) pCR rate. None of the patients with a pCR have had a recurrence. HDI and pembrolizumab were discontinued in 73% and 43% of patients, respectively. Correlative analyses suggested that intratumoral PD-1/PD-L1 interaction and HLA-DR expression are associated with pCR (P = 0.002 and P = 0.008, respectively).ConclusionsNeoadjuvant concurrent HDI and pembrolizumab demonstrated promising clinical activity despite high rates of treatment discontinuation. pCR is a prognostic indicator.See related commentary by Menzies et al., p. 4133