Rationale:
Single-cell RNA sequencing (scRNA-seq) has provided an unbiased assessment of specific profiling of cell populations at the single-cell level. Conventional renal biopsy and bulk RNA-seq only average out the underlying differences, while the extent of chronic kidney transplant rejection (CKTR) and how it is shaped by cells and states in the kidney remain poorly characterized. Here, we analyzed cells from CKTR and matched healthy adult kidneys at single-cell resolution.
Methods:
High-quality transcriptomes were generated from three healthy human kidneys and two CKTR biopsies. Unsupervised clustering analysis of biopsy specimens was performed to identify fifteen distinct cell types, including major immune cells, renal cells and a few types of stromal cells. Single-sample gene set enrichment (ssGSEA) algorithm was utilized to explore functional differences between cell subpopulations and between CKTR and normal cells.
Results:
Natural killer T (NKT) cells formed five subclasses, representing CD4+ T cells, CD8+ T cells, cytotoxic T lymphocytes (CTLs), regulatory T cells (Tregs) and natural killer cells (NKs). Memory B cells were classified into two subtypes, representing reverse immune activation. Monocytes formed a classic CD14+ group and a nonclassical CD16+ group. We identified a novel subpopulation [myofibroblasts (MyoF)] in fibroblasts, which express collagen and extracellular matrix components. The CKTR group was characterized by increased numbers of immune cells and MyoF, leading to increased renal rejection and fibrosis.
Conclusions:
By assessing functional differences of subtype at single-cell resolution, we discovered different subtypes that correlated with distinct functions in CKTR. This resource provides deeper insights into CKTR biology that will be helpful in the diagnosis and treatment of CKTR.
There are many hydrogen-bearing components in shale, including kerogen, free oil, adsorbed oil, free water, adsorbed water, and structural water. Measuring the content and distribution of each component is important to understand the occurrence mechanism of shale oil. The nuclear magnetic resonance (NMR) T 1 −T 2 map can be used as a non-destructive technique to distinguish hydrogen-bearing components in shale. In this paper, we examine the relaxation characteristics of kerogen, shale, and clay minerals in continental shale under different oil or water conditions using high-resolution low-field NMR instruments (frequency is 21.36 MHz, and echo time is 0.07 ms). The NMR T 1 −T 2 map division method was established for each hydrogen-bearing component. The relaxation characteristics of each component are as follows: (1) Kerogen has the highest T 1 /T 2 ratio; oil exhibits a higher T 1 /T 2 ratio than that of water; and the mobility of water is greater than that of oil under saturated conditions. (2) The transverse relaxation time of the free state is greater than the adsorbed state for oil and water. (3) Intergranular pores of clay-rich continental shale shrink after saturation with water and result in the main peak of the T 2 value of free water at less than 1 ms, which differs from marine shale. (4) Kerogen and structural water account for a large proportion of NMR signals in continental shale. ( 5) The signals of some components in T 1 −T 2 maps overlap because of the resolution limitation of the NMR instrument. Organic matter abundance and oil saturation of shale, estimated by the NMR T 1 − T 2 map method, were in good agreement with the pyrolysis and distillation experiments, which demonstrates the reliability of the NMR T 1 −T 2 map division method for each hydrogen-bearing component in continental shale.
Intrathecal midazolam causes antinociception by combining with spinal cord benzodiazepine receptors. This effect is reversible with doses of naloxone, suggesting involvement of spinal kappa or delta but not mu opioid receptors. The antinociceptive effects of intrathecally administered drugs in the spinal cord were demonstrated by measurements of the electrical current threshold for avoidance behaviour in rats with chronically implanted lumbar intrathecal catheters. A comparison was made of suppression by two opioid selective antagonists (nor-binaltorphimine (kappa selective) and naltrindole (delta selective)) of spinal antinociception caused by equipotent doses of opioids selective for different receptor subtypes (U-50488H (kappa), DSLET and DSBULET (delta), fentanyl (mu)) and the benzodiazepine midazolam. Nor-binaltorphimine selectively suppressed the effects of U-50488H but not midazolam or fentanyl. However, the delta selective antagonist, naltrindole, caused dose-related suppression of antinociception produced by both delta opioid agonists and midazolam with the same ED50 (0.5 nmol). We conclude that intrathecal midazolam caused spinally mediated antinociception in rats by a mechanism involving delta opioid receptor activation.
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