Search

Platelet transfusions are critical for severe thrombocytopenia but depend on blood donors. The shortage of donors and the potential of universal HLA-null platelet products have stimulated research on the ex vivo differentiation of human pluripotent stem cells (hPSCs) to platelets. We recently established expandable immortalized megakaryocyte cell lines (imMKCLs) from hPSCs by transducing MYC, BMI1, and BCL-XL (MBX). imMKCLs can act as cryopreservable master cells to supply platelet concentrates. However, the proliferation rates of the imMKCLs vary with the starting hPSC clone. In this study, we reveal from the gene expression profiles of several MKCL clones that the proliferation arrest is correlated with the expression levels of specific cyclin-dependent kinase inhibitors. Silencing CDKN1A and p53 with the overexpression of MBX was effective at stably inducing imMKCLs that generate functional platelets irrespective of the hPSC clone. Collectively, this improvement in generating imMKCLs should contribute to platelet industrialization and platelet biology., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Opioids are associated with wide inter-individual variability in the analgesic response and a narrow therapeutic index. This may be partly explained by the presence of single nucleotide polymorphisms (SNPs) in genes encoding molecular entities involved in opioid metabolism and receptor activation. This paper describes the investigation of SNPs in three genes that have a functional impact on the opioid response: OPRM1, which codes for the μ-opioid receptor; ABCB1 for the ATP-binding cassette B1 transporter enzyme; and the calcium channel complex subunit CACNA2D2. The genotyping was combined with an analysis of plasma levels of the opioid peptide β-endorphin in 80 well-defined patients with chronic low back pain scheduled for spinal fusion surgery, and with differential sensitivity to the opioid analgesic remifentanil. This patient group was compared with 56 healthy controls., Results: The plasma β-endorphin levels were significantly higher in controls than in pain patients.A higher incidence of opioid-related side effects and sex differences was found in patients with the minor allele of the ABCB1 gene. Further, a correlation between increased opioid sensitivity and the major CACNA2D2 allele was confirmed. A tendency of a relationship between opioid sensitivity and the minor allele of OPRM1 was also found., Conclusions: Although the sample cohort in this study was limited to 80 patients it appears that it was possible to observe significant correlations between polymorphism in relevant genes and various items related to pain sensitivity and opioid response. Of particular interest is the new finding of a correlation between increased opioid sensitivity and the major CACNA2D2 allele. These observations may open for improved strategies in the clinical treatment of chronic pain with opioids.

We estimated the actual error rate during ligase detection reaction (LDR), and confirmed that DNA sequences around 3' ends are greatly influenced on the specificity of LDR. Its specificity is increased about 1000 times by introducing a mismatch base near the 3' ends., (Copyright (c) 2009 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.)

The analysis of hepatitis B virus (HBV) mutations is important for understanding HBV progression and for deciding on appropriate clinical treatments. However, it is difficult to determine the quantitative abundance of various mutants in heterogeneous mixtures by conventional methods such as direct sequencing or the TaqMan assay. In this study, we investigated the possibility of using both allele-specific oligonucleotide hybridization (ASOH) and allele-specific oligonucleotide competitive hybridization (ASOCH) with the Handy Bio-Strand system for the quantitative identification of three well-defined HBV variants: the basal core promoter (BCP) mutations (nt1762 and nt1764), the pre-core (PC) mutation (nt1896), and variance at nt1858. Using standardized mixtures of wild-type and mutant DNA, optimal hybridization conditions for ASOH and ASOCH were determined. Next, the performance of these methods was evaluated using actual serum DNAs from HBV patients. Excellent reproducibility was obtained both in the analysis of internal positive controls and in the semi-quantitative categorization of heterogeneous viral mixtures into five abundance groups (0%, 25%, 50%, 75%, and 100% mutant virus). Combined with real-time PCR to determine the HBV viral load, this hybridization method offers a new tool with applications both in HBV clinical research and treatment., (2009 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.)

Biotinylated magnetic nanoparticles were constructed by displaying biotin acceptor peptide (BAP) or biotin carboxyl carrier protein (BCCP) on the surface of bacterial magnetic particles (BacMPs) synthesized by Magnetospirillum magneticum AMB-1. BAP-displaying BacMPs (BAP-BacMPs) were extracted from bacterial cells and incubated with biotin and Escherichia coli biotin ligase. Then the in vitro biotinylation of BAP-BacMPs was confirmed using alkaline phosphatase-labeled antibiotin antibody. In contrast, BacMPs displaying the intact 149 residues of AMB-1 BCCP (BCCP-BacMPs) and displaying the COOH-terminal 78 residues of BCCP (BCCP78-BacMPs) were biotinylated in AMB-1 cells. The in vivo biotinylation of BCCP-BacMPs and BCCP78-BacMPs was thought to be performed by endogenous AMB-1 biotin ligase. Streptavidin was introduced onto biotinylated BacMPs by simple mixing. In an analysis using tetramethyl rhodamine isocyanate-labeled streptavidin, approximately 15 streptavidin molecules were shown to be immobilized on a single BCCP-BacMP. Furthermore, gold nanoparticle-BacMP composites were constructed via the biotin-streptavidin interaction. The conjugation system developed in this work provides a simple, low-cost method for producing biotin- or streptavidin-labeled magnetic nanoparticles. Various functional materials can be site selectively immobilized on these specially designed BacMPs. By combining the site-selective biotinylation technology and the protein display technology, more innovative and attractive magnetic nanomaterials can be constructed.

A single-nucleotide-polymorphism-typing method using a novel three-dimensional DNA microarray, Bio-Strand, is promising because it is rapid, inexpensive and easily automated. It has been developed with the intent to overcome the drawbacks of conventional DNA microarrays, which use flat surfaces and impermeable materials such as glass slides; Bio-Strand as a novel DNA microarray, with its permeability, has a significantly improved stability compared with conventional DNA microarrays that use impermeable materials. In this study, we have developed a simple method of pretreating a polyamide monofilament to increase its surface area and to make it permeable, which makes Bio-Strand more sensitive and stable, allowing it to be adapted for clinical diagnostic applications. The fluorescence signal obtained with a nylon 6 monofilament pretreated under optimal conditions (hydrolysis by 5 M HCl/ethanol followed by washing with 50% ethanol and 100% ethanol) was significantly stronger than that obtained with an untreated monofilament.

Transcripts of alpha-(1,3)-fucosyltransferases in human epithelial cancer and leukemia cell lines were analyzed by Northern blotting and reverse transcriptase mediated-polymerase chain reaction using specific probes and primers which can discriminate between the transcripts derived from the four alpha-(1,3)-fucosyltransferase genes Fuc-TIII, IV, V, and VI. Flow cytometric analysis of the sialyl Le(x) and sialyl Le(a) antigens was also performed on the same cell lines. The sialyl Le(x) antigen was expressed on 14 of 15 epithelial cancer cell lines, and the sialyl Le(a) antigen was detected on 8 of them. The message of Fuc-TIII was detected in most of the epithelial cancer cell lines (14 of 15), which correlated with the surface expression of these carbohydrate determinants. In addition, the messages of Fuc-TIV and Fuc-TVI were detected in most epithelial cancer cell lines, while the message of Fuc-TV was undetectable in most of them. On the other hand, all leukemia cell lines were positively stained for sialyl Le(x), but none of them was stained for sialyl Le(a) in flow cytometry. The messages of Fuc-TIV++ were detected in all leukemia cell lines tested. Small quantities of Fuc-TIII, V, and/or VI messages were also detected in some leukemia cell lines in reverse transcriptase mediated-polymerase chain reaction analysis. These studies indicate that alpha-(1,3)-fucosyltransferase activities in epithelial cancer and leukemia cell lines are mixtures of multiple molecular species of alpha-(1,3)-fucosyltransferases. It is natural that epithelial cancer cells contain a significant amount of Fuc-TIII mRNA and leukemia cell lines contain Fuc-TIV mRNA, since their normal counterparts, normal epithelial cells and leukocytes, respectively, are known to contain these fucosyltransferases. The unexpectedly frequent occurrence of Fuc-TIV mRNA in epithelial cancer cell lines may be related to their retro-differentiation associated with tumorigenesis. Another unexpected finding was a weak but significant expression of the alpha-(1,3)-fucosyltransferases Fuc-TIII, V, and/or VI in leukemia cell lines detected by reverse transcriptase mediated-polymerase chain reaction analysis. Since these enzymes are known to be capable of synthesizing the sialyl Le(x) determinant, this finding implies a possibility that some of them may be involved in the synthesis of sialyl Le(x) in leukemia cells.