Ketamine administration causes cognitive impairment by destroying the circulation function of the glymphatic system.

BACKGROUND: Ketamine, as a non-competitive antagonist of N-methyl-D-aspartate (NMDA) receptors, was originally used in general anesthesia. Epidemiological data show that ketamine has become one of the most commonly abused drugs in China. Ketamine administration might cause cognitive impairment; however, its molecular mechanism remains unclear. The glymphatic system is a lymphoid system that plays a key role in metabolic waste removal and cognitive regulation in the central nervous system. METHODS: Focusing on the glymphatic system, this study evaluated the behavioral performance and circulatory function of the glymphatic system by building a short-term ketamine administration model in mice, and detected the expression levels of the 5-HT2c receptor, ΔFosb, Pten, Akt, and Aqp4 in the hippocampus. Primary astrocytes were cultured to verify the regulatory relationships among related indexes using a 5-HT2c receptor antagonist, a 5-HT2c receptor short interfering RNA (siRNA), and a ΔFosb siRNA. RESULTS: Ketamine administration induced ΔFosb accumulation by increasing 5-HT2c receptor expression in mouse hippocampal astrocytes and primary astrocytes. ΔFosb acted as a transcription factor to recognize the AATGATTAAT bases in the 5' regulatory region of the Aqp4 gene (-1096 bp to -1087 bp), which inhibited Aqp4 expression, thus causing the circulatory dysfunction of the glymphatic system, leading to cognitive impairment. CONCLUSIONS: Although this regulatory mechanism does not involve the Pten/Akt pathway, this study revealed a new mechanism of ketamine-induced cognitive impairment in non-neuronal systems, and provided a theoretical basis for the safety of clinical treatment and the effectiveness of withdrawal.

Molecular and computational analysis of 45 samples with a serologic weak D phenotype detected among 132,479 blood donors in northeast China.

BACKGROUND: RH1 is one of the most clinically important blood group antigens in the field of transfusion and in the prevention of fetal incompatibility. The molecular analysis and characterization of serologic weak D phenotypes is essential to ensuring transfusion safety. METHODS: Blood samples from a northeastern Chinese population were randomly screened for a serologic weak D phenotype. The nucleotide sequences of all 10 exons, adjacent flanking intronic regions, and partial 5' and 3' untranslated regions (UTRs) were detected for RHD genes. Predicted deleterious structural changes in missense mutations of serologicl weak D phenotypes were analyzed using SIFT, PROVEAN and PolyPhen2 software. The protein structure of serologic weak D phenotypes was predicted using Swiss-PdbViewer 4.0.1. RESULTS: A serologic weak D phenotype was found in 45 individuals (0.03%) among 132,479 blood donors. Seventeen distinct RHD mutation alleles were detected, with 11 weak D, four partial D and two DEL alleles. Further analyses resulted in the identification of two novel alleles (RHD weak D 1102A and 399C). The prediction of a three-dimensional structure showed that the protein conformation was disrupted in 16 serologic weak D phenotypes. CONCLUSIONS: Two novel and 15 rare RHD alleles were identified. Weak D type 15, DVI Type 3, and RHD1227A were the most prevalent D variant alleles in a northeastern Chinese population. Although the frequencies of the D variant alleles presented herein were low, their phenotypic and genotypic descriptions add to the repertoire of reported RHD alleles. Bioinformatics analysis on RhD protein can give us more interpretation of missense variants of RHD gene.

Robust Object Tracking via Local Sparse Appearance Model.

In this paper, we propose a novel local sparse representation-based tracking framework for visual tracking. To deeply mine the appearance characteristics of different local patches, the proposed method divides all local patches of a candidate target into three categories, which are stable patches, valid patches, and invalid patches. All these patches are assigned different weights to consider the different importance of the local patches. For stable patches, we introduce a local sparse score to identify them, and discriminative local sparse coding is developed to decrease the weights of background patches among the stable patches. For valid patches and invalid patches, we adopt local linear regression to distinguish the former from the latter. Furthermore, we propose a weight shrinkage method to determine weights for different valid patches to make our patch weight computation more reasonable. Experimental results on public tracking benchmarks with challenging sequences demonstrate that the proposed method performs favorably against other state-of-the-art tracking methods.

RKTG overexpression inhibits proliferation and induces apoptosis of human leukemia cells via suppression of the ERK and PI3K/AKT signaling pathways.

Raf kinase trapping to Golgi (RKTG) is reported to be a tumor suppressor in a number of solid tumors due to its negative modulation of the Ras/Raf/mitogen-activated protein kinase kinase/extracellular signal-regulated kinase (ERK) pathways. However, the role of RKTG in the progression of leukemia remains unknown. In the present study, a human leukemia U937 cell line overexpressing RKTG was established, and the effect of RKTG on proliferation, cell cycle and apoptosis of human leukemia cells was analyzed. The results of the present study demonstrated that exogenous overexpression of RKTG significantly inhibited cell proliferation, which was accompanied by cell cycle arrest. Apoptosis assay and Hoechst staining demonstrated that the percentage of apoptotic cells in RKTG overexpressing cells was markedly increased. Furthermore, western blotting showed that RKTG overexpression significantly increased the level of cleaved caspase 3, B-cell lymphoma 2 (Bcl2)-associated X apoptosis regulator and reduced the level of Bcl-2. In addition, the activation of ERK and phosphoinositide 3-kinase (PI3K)/AKT serine/threonine kinase 1 signaling pathways in human leukemia cells was also suppressed by RKTG overexpression. In conclusion, the present study demonstrated the tumor-suppressive effect of RKTG on human leukemia cells, which seem to be partially dependent on the suppression of ERK and PI3K/AKT signaling. Overexpression of RKTG may be a potential therapeutic target for the treatment of leukemia.

[Indentification and Sequence Analysis of A Individual with B305 Blood Group Gene Subtypes of ABO Variant].

OBJECTIVE: To investigate and identify the molecular and biological characteristics of B305 blood group gene subtypes of a ABO variant. METHODS: The individual was confirmed by standard serological techniques. The genotyping and sequencing were performed by using polymerase chain reaction-sequence specific primer (PCR-SSP), direct sequencing and gene cloning for Exon 6 and exon 7 of ABO locus respectively. RESULTS: B antigen was detected on red blood cells of the proband and there was anti-A antibody in the serum. The PCR-SSP result showed BO1 phenotype. DNA sequencing showed 261delG, 297A/G, 425T/C, 526C/G, 657C/T, 703A/G, 796C/A, 803G/C and 930G/A heterozygote in exon 6 to exon 7. After cloning and sequencing, 2 alleles B305 and O01 were obtained. The sequence of B305 allele had one nucleotide mutation (T to C) at position 425 compared with that of B101 allele, resulting in an amino acid substitution (M142T). CONCLUSION: T>C at nt425 of α-1,3 galactosyltransferase gene can result in B305 blood group gene subtypes, which reduce the expression of B antigen.

[Molecular genetic analysis of two individuals with Bw subtypes of ABO variant].

OBJECTIVE: To investigate the molecular characteristics of Bw subgroup of ABO variant. METHODS: Two individuals with Bw phenotypes were confirmed by standard serological assays. ABO genotype was analyzed with polymerase chain reaction-sequence specific primer (PCR-SSP) method. Exons 6-7 of B genes were amplified by specific PCR, and the PCR product was subjected to direct sequencing. RESULTS: The probands were identified as Bw phenotype by serological assays. As detected by PCR-SSP, the genotypes of the two probands were both B/O2. Compared with the wild-type B101, the B allele in one individual has harbored a missense mutation (C721T) in exon 7, which resulted in an amino acid substitutions (R241S). In the second individual, the B allele has harbored a missense mutation (C278T) in exon 6, which also resulted in an amino acid substitution (P93L). CONCLUSION: A Bw03 allele and a Bw12 allele were identified, which resulted in varied intensity of B antigen expression.